Band 10, Heft 1

Microwave-absorbing materials with good microwave absorption performance are of great interest for military applications and human health, which is threatened by electromagnetic radiation pollution. Herein, the design and synthesis of multi-componential metal-hybridized graphene composites via freeze drying and pyrolysis of ferrocene hydrazone complex precursor are reported. Various magnetic nanoparticles are loaded on reduced graphene oxide (rGO) via controlling their pyrolysis temperature. The complex electromagnetic parameters of these hybrids are therefore regulated by the hybrid components. Among them, rGO hybridized by the sea-island-like Fe 2 O 3 /Fe 3 O 4 /FeNi 3 multi-componential metals shows a good balance of dielectric and magnetic constants. Thus, the improved impedance matching with free space brings about a superior electromagnetic wave absorption performance, especially on the effective absorption bandwidth. The minimum reflection loss (RL) of the hybrids is as low as −40.3 dB at 11 GHz with the RL bandwidth of −10 dB being 4.55 GHz (from 9.25 to 13.8 GHz).

Successful repair of long-distance peripheral nerve injuries remains a challenge in the clinic. Rapid axon growth is a key to accelerate nerve regeneration. Herein, a pure silk fibroin (SF) hydrogel with a combination of high-strength and aligned microgrooved topographic structure is reported. The hydrogels exhibit excellent mechanical properties with high strength. Good biocompatibility also allows the hydrogels to support cell survival. Significantly, the hydrogel with aligned microgrooved structures enables the aligned growth of Schwann cells. Moreover, the hydrogel holds a strong capacity for promoting axon growth and guiding neurite sprouting. Thus, this micropatterned SF hydrogel would have great potential for peripheral nerve regeneration.

Fast charge transfer and lithium-ion transport in the electrodes are necessary for high performance Li–S batteries. Herein, a N-doped carbon-coated intercalated-bentonite (Bent@C) with interlamellar ion path and 3D conductive network architecture is designed to improve the performance of Li–S batteries by expediting ion/electron transport in the cathode. The interlamellar ion pathways are constructed through inorganic/organic intercalation of bentonite. The 3D conductive networks consist of N-doped carbon, both in the interlayer and on the surface of the modified bentonite. Benefiting from the unique structure of the Bent@C, the S/Bent@C cathode exhibits a high initial capacity of 1,361 mA h g −1 at 0.2C and achieves a high reversible capacity of 618.1 m Ah g −1 at 2C after 500 cycles with a sulfur loading of 2 mg cm −2 . Moreover, with a higher sulfur loading of 3.0 mg cm −2 , the cathode still delivers a reversible capacity of 560.2 mA h g −1 at 0.1C after 100 cycles.

Peripheral nerve injury has seriously affected patient’s health and life. Schwann cells play an important role in peripheral nerve regeneration. However, the effect of the current tissue engineered scaffolds for promoting Schwann cells growth is still not as good as that of autologous graft. In this study, new developed three-dimensional gellan gum/starch (GG/ST) scaffolds with various printing gap for Schwann cells growth were prepared by 3D printing technology. Various physiochemical characterizations of the printed scaffolds were performed including morphology, rheological behavior, swelling ratio, and degradation behavior. The cytotoxicity and biocompatibility of the scaffolds were evaluated using L929 fibroblasts and RSC96 Schwann cells, respectively. The results displayed that the GG/ST scaffold exhibited a porous network structure. The cross-sectional pore density of the hydrogel had a tendency to increase with the ascending printing gap. The swelling rate and degradation rate of the hydrogel gradually increased and eventually reached an equilibrium state. The rheological test results showed that the scaffolds had good printability. MTT cytotoxicity test and CCK-8 cell proliferation test displayed that the scaffold was nontoxic, and Schwann cells could grow well on the scaffold after 5 days of culture, whereas the number of cells on the scaffold with the printing gap of 3 mm was the largest. These results indicated that the GG/ST scaffold prepared by 3D printing technology may have a potential application in peripheral nerve regeneration.

Although Cu–Al 2 O 3 composites have good comprehensive performance, higher mechanical properties and arc erosion resistance are still required to meet heavy-duty applications such as electromagnetic railguns. In this work, a novel hybrid SiC w /Cu–Al 2 O 3 composite was successfully prepared by combining powder metallurgy and internal oxidation. The microstructure and mechanical behavior of the SiC w /Cu–Al 2 O 3 composite were studied. The results show that nano-Al 2 O 3 particles and micro-SiC w are introduced into the copper matrix simultaneously. Well-bonded interfaces between copper matrix and Al 2 O 3 particles or SiC w are obtained with improved mechanical and arc erosion resistance of SiC w /Cu–Al 2 O 3 composite. The ultimate tensile strength of the SiC w /Cu–Al 2 O 3 composite is 508.9 MPa, which is 7.9 and 56.1% higher than that of the Cu–Al 2 O 3 composite and SiC w /Cu composite, respectively. The strengthening mechanism calculation shows that Orowan strengthening is the main strengthening mechanism of the SiC w /Cu–Al 2 O 3 composite. Compared with Cu–Al 2 O 3 composite, the hybrid SiC w /Cu–Al 2 O 3 composite has lower arc time and energy and better arc stability. Graphical abstract Copper matrix composites reinforced with nano-Al 2 O 3 particles and micro-SiC whiskers were prepared. Nano-Al 2 O 3 particles are uniformly dispersed in the copper matrix (Figure a), and there is an obvious amorphous transition layer at the interface between the copper matrix and SiC w (Figure d). Nano-Al 2 O 3 particles and micro-SiC whiskers reinforcing phase synergistically strengthen the SiC w /Cu–Al 2 O 3 composite.

Conventional engineering stress–strain curve could not accurately describe the local deformability of the tensile necking part because the strain is calculated by assuming that the tensile specimen was deformed uniformly. In this study, we used 3D optical measuring digital image correlation to systematically measure the full strain field and actual flow stress in the necking region of ultrafine-grained (UFG) Al. The post-necking elongation and strain hardening exponent of the UFG Al were measured as 80% and 0.10, slightly smaller than those of the coarse-grained Al (117% and 0.28), suggesting the high plastic deformability of the UFG Al under complex stress state. Microstructural studies revealed the shear and ductile fracture, numerous micro-shear bands, and elongated UFG grains in the UFG Al, which are controlled by cooperative grain boundary sliding and multiple dislocation slips.

In this paper, the mechanical behavior of gradient nano-grained copper under uniaxial deformation was investigated using molecular dynamics simulations. The stress response was found to be different in the regions with different grain sizes, which was attributed to the different dislocation activities due to the dislocation-grain boundary synergies. The phenomenon of grain rotation was observed and a program was developed to accurately evaluate the grain rotation and explore its dependence on the grain size and the initial crystal orientation. It is found that all grains tend to rotate to the 30° orientation, consistent with the activation theory of the slip systems under the uniaxial deformation. The rotation magnitude is larger for larger grains, but the rotation rate is more diversely distributed for smaller grains, indicating more disturbance from grain boundary mechanisms such as the grain boundary sliding and the grain boundary diffusion for smaller grains. The effect of temperature on the grain rotation is also investigated, showing an increase of the dispersion of grain rotation distribution with the increase of temperature. This paper aims at providing insights into the synergistic deformation mechanisms from dislocations and grain boundaries accounting for the exceptional ductility of the gradient nano-grained metals.

Because of its priority to remove anions, nano-layered double hydroxide (LDH) was incorporated to improve the sulfate attack corrosion resistance of cement-based materials. Herein, the synthesis of high-efficiency LDH for removal of SO 4 2 − {\text{SO}}_{4}^{2-} is necessary. In this study, LDH with different Mg/Al ratios was synthesized under different dual solvent systems (water and ethylene glycol/ethanol/tetrapropylammonium hydroxide). Based on the adsorption experimental results, the LDH synthesized with n (Mg:Al) = 2:1 under water and ethanol solvent systems (ET2.0) exhibits the best adsorption capacity. The d (003) of LDH synthesized with n (Mg:Al) = 2:1 under different dual solvent systems are 0.7844, 0.7830, and 0.7946 nm, respectively. Three LDH belong to LDH- NO 3 − {\text{NO}}_{3}^{-} . The results indicated that their surface charges show obvious difference synthesized under different dual solvent systems, which leads to differences in adsorption performance. The adsorption experimental results show that ET2.0 followed pseudo second-order kinetics and Langmuir model. The ET2.0 removed SO 4 2 − {\text{SO}}_{4}^{2-} through anion substitution and electrostatic interaction and exhibited excellent adsorption rate with the maximum adsorption capacity of 95.639 mg/g. The effects of pore solution anion (OH − , Cl − , and CO 3 2 − {\text{CO}}_{3}^{2-} ) on the removal of SO 4 2 − {\text{SO}}_{4}^{2-} by the ET2.0 are limited.

Titanium dioxide (TiO 2 ) is the most effective photocatalysts for low-cost degradation of organic pollutant; however, the wide band gap and the high recombination rate of the charge carriers are drawbacks that hinders it practical application. In this study, TiO 2 and titanium mixed metal oxides ternary (V/Ag/TiO 2 ) nanocatalyst was synthesized through a microwave-assisted sol–gel route using Ti(C 4 H 9 O) 4 , NH 4 VO 3 , and AgNO 3 as precursors. The XRD analysis of the synthesized TiO 2 and V/Ag/TiO 2 depicts lattice fringes for rutile and anatase crystalline phases. Raman spectra indicate the formation of a mesoporous multiphase sample mixture of rutile and anatase phases. The spectrum shift to the visible light region was demonstrated by the UV-visible spectroscopy analysis. Diffuse reflectance spectroscopy (DRS) reveals a reduced band gap of 2.9 eV for TiO 2 and 2.65 eV for V/Ag/TiO 2 . Brunauer–Emmett–Teller (BET) indicates a large surface area of 92.8 and 84.8 m 2  g −1 for TiO 2 and V/Ag/TiO 2 , respectively. Nitrogen adsorption–desorption isotherm exhibits type IV isotherm, signifying the presence of the mesoporous structure. SEM portrays a cluster of rod-like aggregate particles, while the HRTEM analysis illustrates nanoparticles of rod-like cylindrical shape with a homogeneous size diameter. The synthesized nanocatalyst demonstrated a significant photocatalytic ability in the degradation of methyl orange (MO) and methylene blue (MB). V/Ag/TiO 2 shows higher activity in the visible region. Thus, the present report suggests efficient, suitable, and economical microwave-assisted sol–gel techniques to yield V/Ag/TiO 2 nanocatalysts with harnessed photocatalytic performance for the degradation of toxic organic pollutants in the presence of visible light irradiation. Graphical abstract

Basalt fiber (BF), because of having high strength-to-cost ratio, could be suitable for industrial applications replacing the carbon and glass fibers. However, the lack of surface functionality restricts its potential interfacial interactions with the reinforced matrix. Various surface modification approaches are used to tailor the surface properties of BFs such as coating nanomaterials and attaching chemical moieties. In this study, a successful deposition of graphene on basalt fabric was done using eco-friendly and simple electrophoretic deposition method. The confirmation of attached graphene oxide and graphene was done through the scanning electron microscope, Raman spectroscopy, and X-ray photoelectroscopy. Later, the effect of graphene coating on the thermal properties of BF was studied through thermogravimetric analysis and differential scanning calorimetry. Results show that the graphene was successfully coated on BF, and in the presence of graphene coating, the crystallization of BF delayed from 697 to 716°C because of the formation of a protective layer of graphene. Graphene-coated BF could be used further in fiber-reinforced composites to improve the interfacial interaction between the matrix and fiber.

When using a wrench, the nut is easily damaged due to improper operation or impact. Although coating a polymer layer on the surface of the wrench can effectively solve the above problem, the layer is easy to be deboned due to the lack of adhesion between the polymer and the surface of the wrench. Herein, we implemented an anodizing treatment strategy on the surface of the wrench to obtain a porous oxide film. Interestingly, during the anodization process, micro-nanopores with a specific diameter can be obtained by adjusting the voltage, temperature, and electrolyte concentration. Furthermore, the ammonium fluoride/ethylene glycol electrolyte was used to etch the formed large hole to form the large hole sleeve small hole structure. In order to inject polyphenylene sulfide (PPS) molecules into multiscale holes to form a pinning effect, we also used nano molding technology to inject PPS into the metal surface. The results showed that the adhesion between PPS and the wrench was greatly improved compared with the commonly used dip coating method.

Sintered carbon nanotube (CNT) blocks and porous CNT sponges were prepared, and their thermoelectric properties were measured. The maximum dimensionless thermoelectric figure-of-merit, ZT , at room temperature of the sintered single-walled carbon nanotube (SWCNT) block is 9.34 × 10 −5 , which is twice higher than that of the sintered multi-walled carbon nanotube (MWCNT) block in this work and also higher than that of other sintered MWCNT blocks reported previously. In addition, the porous MWCNT sponge showed an ultra-low thermal conductivity of 0.021 W/(m K) and significantly enhanced ZT value of 5.72 × 10 −4 at room temperature and 1 atm. This ZT value is higher than that of other 3D macroscopic pure CNT materials reported. The pronounced enhancement of the ZT in the porous MWCNT sponge is attributed to the ultra-low density, ultra-high porosity, and interconnected structure of the material, which lead to a fairly low thermal conductivity and better Seebeck coefficient. The finding of this work provides an understanding for exploring potential enhancement mechanisms and improving the thermoelectric properties of CNT-based thermoelectric composites.

A comprehensive study of the multiscale homogenized thermal conductivities and thermomechanical properties is conducted towards the filament groups of European Advanced Superconductors (EAS) strand via the recently proposed Multiphysics Locally Exact Homogenization Theory (LEHT). The filament groups have a distinctive two-level hierarchical microstructure with a repeating pattern perpendicular to the axial direction of Nb 3 Sn filament. The Nb 3 Sn filaments are processed in a very high temperature between 600 and 700°C, while its operation temperature is extremely low, −269°C. Meanwhile, Nb 3 Sn may experience high heat flux due to low resistivity of Nb 3 Sn in the normal state. The intrinsic hierarchical microstructure of Nb 3 Sn filament groups and Multiphysics loading conditions make LEHT an ideal candidate to conduct the homogenized thermal conductivities and thermomechanical analysis. First, a comparison with a finite element analysis is conducted to validate effectiveness of Multiphysics LEHT and good agreement is obtained for the homogenized thermal conductivities and mechanical and thermal expansion properties. Then, the Multiphysics LEHT is applied to systematically investigate the effects of volume fraction and temperature on homogenized thermal conductivities and thermomechanical properties of Nb 3 Sn filaments at the microscale and mesoscale. Those homogenized properties provide a full picture for researchers or engineers to understand the Nb 3 Sn homogenized properties and will further facilitate the material design and application.

In this study, similar aluminum alloys AA5052 with additional carbon fiber-reinforced polymer composite (CFRP) interlayer were selected to investigate the effect of welding parameters (rotational speed and dwell time) on the mechanical properties, joint efficiency, and microstructure of friction stir spot weld joint. The maximum tensile shear load was 1779.6 N with joint efficiency of 14.6% obtained at rotational speed of 2,000 rpm and 2 s dwell time, which is 39.5% higher than the value at low rotational speed 850 rpm and 2 s dwell time. Meanwhile, the maximum microhardness 58 HV was attained in the keyhole region at rotational speed of 2,000 rpm and dwell time of 5 s, which is 22.4% higher compared to low rotational speed. The SEM-EDS results reveal the presence of intermetallic compounds (Al–Mg–C), which enhance the intermetallic bonding between elements. Graphical abstract

The high-nickel cathode material of LiNi 0.8 Co 0.15 Al 0.05 O 2 (LNCA) has a prospective application for lithium-ion batteries due to the high capacity and low cost. However, the side reaction between the electrolyte and the electrode seriously affects the cycling stability of lithium-ion batteries. In this work, Ni 2+ preoxidation and the optimization of calcination temperature were carried out to reduce the cation mixing of LNCA, and solid-phase Al-doping improved the uniformity of element distribution and the orderliness of the layered structure. In addition, the surface of LNCA was homogeneously modified with ZnO coating by a facile wet-chemical route. Compared to the pristine LNCA, the optimized ZnO-coated LNCA showed excellent electrochemical performance with the first discharge-specific capacity of 187.5 mA h g −1 , and the capacity retention of 91.3% at 0.2C after 100 cycles. The experiment demonstrated that the improved electrochemical performance of ZnO-coated LNCA is assigned to the surface coating of ZnO which protects LNCA from being corroded by the electrolyte during cycling. Graphical abstract

Based on the thermal theory of Newtonian mechanics, the pressure difference in the macro channels will drive the gas flow until the pressure difference inside is zero. However, the 12-year vacuum packaging experiments in our laboratory showed that when the macroscopic channel is reduced to a critical size and reaches the nanometer level, the gas flow inside the channel is hindered, that is, the differential pressure cannot become zero. To explain this paradoxical phenomenon, this study analyzes the flow of air molecules in the channel by using the De Broglie’s matter waves and Heisenberg’s uncertainty principle. Based on the law of quantum mechanics, when the diameter of the nanochannel is reduced to a certain size, it has a localized high pressure in the channel, which impedes the gas flow. This article introduces quantum mechanics into nanochannel’s gas fluid dynamics for the first time, expanding the new direction of fluid mechanics. Graphical abstract

Nano molding technology (NMT) has shown great potential in the preparation of metal/resin composites, which can integrate resin and metal into a lightweight, high-strength metal matrix composite. However, due to the poor interfacial bonding strength between metal and polymer, the application of the metal/polymer composites is limited. In this paper, we proposed a novel method to improve the bonding strength between Fe–Co–Ni alloy and epoxy resin by Nano Perfusion Technology (NPT), featuring in situ growth of carbon nanotubes (CNTs) in the pores on anodized Fe–Co–Ni alloy porous surface, followed by a perfusion of epoxy resin throughout the pores that had been in situ grown CNTs. Due to the “anchor effect” of CNTs, the bonding strength between the epoxy and the alloy matrix is improved. The results showed that the interfacial bonding between the in situ CNTs-modified alloy and the resin was significantly improved compared to the metal-resin composites surface treated with T-treatment in traditional method of NMT. The maximum interfacial bonding force of the alloy-CNTs/epoxy composite reached up to 691.80 N, which was 460, 315, and 267% higher than those by mechanical treatment, without CNTs and T-treatment, respectively. This work provides a new approach to protect metals or alloys from environmental corrosion, impact damage, and so on.

As the use time of concrete structures increases, defects such as concrete cracks, corrosion and exposure of steel bars gradually appear, resulting in additional repair of concrete structures to increase their durability and life. In this article, the effects of nano-modified polymer cement-based materials as repair material on the bending behavior of repaired concrete beams were studied. Based on the moment, deflection, strain, surface quality and cracking development monitor of repaired concrete beams, the bending behavior of repaired beams with polymer, nano-modified polymer and fibers was compared and the failure mechanism of the beams was analyzed. The results showed that the nano-modified polymer cement-based materials are helpful in improving the performance of repaired beams, manifested by the increase in the ultimate bending moment and the significant improvement in the quality of the interface between repair and matrix concrete. Compared with polymer cement-based materials, nano-modified polymer cement-based materials result in a 27% increase in ultimate bending moment of the repaired beam and a 58% increase in cracking moment, while reducing the total number of cracks by 23% and the average width of cracks by 17% in the repaired beam. This article demonstrated the availability of nanomaterials for improving the loading behavior of structural components with polymer-modified cement-based materials.

Using nanomaterials to enhance concrete performance is of particular interest to meet the safety and functionality requirements of engineering structures. However, there are few comprehensive comparisons of the effects of different nanomaterials on the properties of ultra-high performance concretes (UHPCs) with a compressive strength of more than 150 MPa. The aim of the present study was to assess the coupling effects of nanomaterials and steel fibres on the workability and compressive performance of UHPC. Three types of nanomaterials, nano-SiO 2 (NS), nano-calcium carbonate (NC), and carbon nanofibre (CNF), were each added into UHPC mixes by quantity substitution of the binder; two types of steel fibres were investigated; and two mixing methods were used for casting the UHPC. In addition, the effect of curing age (7 or 28 days) on the compressive performance of the mixtures was considered. Comprehensive studies were conducted on the effects of these test variables on the fluidity, compressive strength, failure mode, and microstructure. The results show that the combination of these nanomaterials and steel fibres can provide good synergetic effects on the compressive performance of UHPC and that the addition of CNF results in a greater enhancement than the addition of NS or NC. The addition of NS, not CNF or NC, has a considerable negative influence on the fluidity of the UHPC paste. It is suggested that reducing the agglomeration of the nanomaterials would further improve the performance of the resulting UHPC. Graphical abstract

High stable nickel nanoparticles (NiNPs) have been successfully synthesized from nickel chloride as the precursor through a simple one-pot solvothermal process. A systematic investigation of the reaction parameters, namely, effects of reaction temperature, pH of precursor solution, the concentration of reactants, and reaction time on the formation of NiNPs, was carried out to obtain the optimal values for the synthesis. The optimum reaction temperature, pH, NiCl 2 ·6H 2 O concentration, and reaction time are 190°C, pH 9, 0.1 M, and 24 h. The characteristic peaks of NiNPs have been confirmed by the Fourier transformer infra-red and surface plasmon resonance, with the presence of –OH stretching bands at 3,593 and 603 cm −1 (interaction with Ni and NiO) and λ max 265 nm, respectively. The X-ray diffraction and transmission electron microscope demonstrated the particle size of about 24 nm (by Scherrer) and 49 nm (Image-J), respectively, with the face center cubic phase. The synthesized NiNPs showed good stability, where the degradation of NiNPs was completed at 800°C with more than 97% residue as depicted by the thermogravimetry analysis. The synthesized NiNPs can be used as fillers to enhance the thermal, mechanical, and electrical properties of polymeric materials. Graphical abstract

Filling and nucleation are the mechanisms of modifying cement paste with nanomaterials, as investigated by previous studies, and are difficult to reflect the different effects of nanomaterials, especially on the changes of cement clinker and hydration products in the cement hydration process. In this study, the mechanisms of modifying cement paste with nano-calcium carbonate (NC), nano-graphene oxide (NG), nano-silica (NS), and nano-titanium dioxide (NT) were investigated by determining the mechanical properties of cement paste treated with nanomaterials and analysing the changes in the cement clinker (tricalcium silicate and dicalcium silicate), hydration products (portlandite and ettringite), and microstructure through many micro-test methods. The results indicate that the incorporation of nanomaterials could improve the early strength of cement paste specimens due to more consumption of cement clinker. Meanwhile, different nanomaterials promote the formation of different hydration products at early ages. C–A–S–H gel, flower-like ettringite, and C–S–H seeds are widely distributed in the cement paste with the incorporation of NC, NG, and NS, respectively. NT exhibits insignificant nucleation effect and has inhibitory effect on portlandite precipitation. This study provides key insights into the mechanism of nanomaterials from the perspective of cement hydration, which may promote the further research and application of nanomaterials in the cement and concrete industries. Graphical abstract

The graphene oxide (GO)-doped nano-CeO 2 was introduced into Cu30Cr10W electrical contact composites by ball milling dispersion, freeze-drying, and spark plasma sintering, resulting in excellent mechanical strength and high arc erosion resistance. The effects of GO and CeO 2 on the microstructure and properties of the composites were investigated. The arc erosion behavior was investigated by the JF04C electrical contact testing apparatus. Consequently, the uniform distribution of CeO 2 nanoparticles hinders the movement of dislocations, GO transformed into reduced graphene oxide (rGO) during high-temperature sintering, and the in situ formation of Cr 3 C 2 between trace carbon atoms and chromium particles at the C–Cu interface, which enhanced the interface combination. Compared with Cu30Cr10W composites, the tensile strength of the two composites was increased by 47 and 36% by importing GO and nano-CeO 2 , respectively. Finally, electrode material migrated from the cathode to the anode, and the rGO delayed the formation of pits and sharp bumps on the contact surface of the electrode and inhibited diffusion of molten metal; when compared with Cu30Cr10W, the GO/CeO 2 –Cu30Cr10W composites have better welding force. Graphical abstract

The present study focused on two dissimilar metal alloys: AA7075-T651 and Ti-6Al-4V alloys with additional carbon fiber-reinforced polymer (CFRP) as an interlayer were welded together by friction stir spot welding (FSSW). The effect of welding parameters (rotational speed and dwell time) and carbon fiber-reinforced polymer on mechanical and microstructural properties of a weld joint was investigated. The obtained results explore the parametric effects on mechanical properties of the weld joint. The maximum tensile shear load 2597.8 N was achieved at the rotational speed of 2,000 rpm and dwell time of 10 s. While at the same rotational speed, 54.7% reduction in the tensile shear load was attained at shorter dwell time of 5 s. Therefore, dwell time plays an important role in the tensile shear load of a weld joint. The scanning electron microscope (SEM-EDS) results show the formation of intermetallic compound of Ti 3 Al and Ti-Al-C that significantly affect the mechanical and microstructural properties of the weld joint. Moreover, the effect of the rotational speed on micro-hardness was found at significant than dwell time. The micro-hardness of the weld joint increase by 18.90% in the keyhole rather than the stir zone and the thermomechanical affected zone, which might be due to the presence of ternary (Ti-Al-C) intermetallic compound. Graphical abstract

The sandwich structures are three- or multilayered structures such that their mechanical properties are better than each single layer. In the current research, a three-layered cylindrical shell including a functionally graded porous core and two reinforced nanocomposite face sheets resting on the Pasternak foundation is used as model to provide a comprehensive understanding of vibrational behavior of such structures. The core is made of limestone, while the epoxy is utilized as the top and bottom layers’ matrix phase and also it is reinforced by the graphene nanoplatelets (GNPs). The pattern of the GNPs dispersion and the pores distribution play a crucial role at the continuous change of the layers’ properties. The sinusoidal shear deformation shells theory and the Hamilton’s principle are employed to derive the equations of motion for the mentioned cylindrical sandwich shell. Ultimately, the impacts of the model’s geometry, foundation moduli, mode number, and deviatory radius on the vibrational behavior are investigated and discussed. It is revealed that the natural frequency and rotation angle of the sandwich shell are directly related. Moreover, mid-radius to thickness ratio enhancement results in the natural frequency reduction. The results of this study can be helpful for the future investigations in such a broad context. Furthermore, for the pipe factories current study can be effective at their designing procedure.

The disposal of non-biodegradable synthetic plastic wastes is linked with air, land, and marine pollutions. Incineration of plastic wastes released toxic substances into the air while recycled plastics end up accumulated in landfill and dumped into the ocean. In this study, novel sugar palm starch reinforced with sugar palm crystalline nanocellulose was blended with poly(lactic acid) (PLA) with various formulations to develop alternative materials potentially substituting conventional plastics. X-ray diffraction analysis demonstrated broad amorphous scattering background with minor diffraction peaks at 2 θ of 19.4° and 22° associated with V H -type and B-type crystal structure for all blend bionanocomposites samples. Higher solubility rates were observed for PLA20TPS80 (96.34%) and PLA40TPS60 (77.66%) associated with higher concentration of plasticizers providing extra space in the polymer chains to be penetrated by water molecules. Increasing PLA content was not necessarily enhancing the water vapor permeability rate. Dynamic mechanical analysis presented a significant increment in storage modulus ( E ′) for PLA60TPS40 (53.2%) compared to the trivial changes of PLA70TPS30 (10%) and PLA80TPS20 (0.6%). However, significant improvement in impact strength occurred only at PLA40TPS60 (33.13%), and further addition showed minor improvement between 12 and 20%. Overall, it is noted that PLA60TPS40 demonstrated adequate functional properties to be used in food packaging application. Graphical abstract

Four methods are applied to calculate the acousto-optic (AO) coupling in one-dimensional (1D) phoxonic crystal (PXC) cavity: transfer matrix method (TMM), finite element method (FEM), perturbation theory, and Born approximation. Two types of mechanisms, the photoelastic effect (PE) and the moving interface effect (MI), are investigated. Whether the AO coupling belongs to linear or quadratic, the results obtained by the perturbation theory are in good agreement with the numerical results. We show that the combination method of FEM and perturbation theory has some advantages over Born approximation. The dependence of linear and quadratic couplings on the symmetry of acoustic and optical modes has been discussed in detail. The linear coupling will vanish if the defect acoustic mode is even symmetry, but the quadratic effect may be enhanced. Based on second-order perturbation theory, the contribution of each optical eigenfrequency to quadratic coupling is clarified. Finally, the quadratic coupling is greatly enhanced by tuning the thickness of the defect layer, which is an order of magnitude larger than that of normal defect thickness. The enhancement mechanism of quadratic coupling is illustrated. The symmetry of the acoustic defect mode is transformed from odd to even, and two optical defect modes are modulated to be quasi-degenerated modes. This study opens up a possibility to achieve tunable phoxonic crystals on the basis of nonlinear AO effects. Graphical abstract

The peripapillary retinal pigment epithelium-basement membrane (ppRPE/BM) layer angle was recently proposed as a potential index for estimating intracranial pressure noninvasively. However, the ppRPE/BM layer angle, measured from the optical coherence tomography (OCT) scans, varied across the radial directions of the optic disc. This made the ppRPE/BM layer angle difficult to be utilized in its full potential. In this study, we developed a mathematical model to quantify the ppRPE/BM layer angles across radial scans in relation to the ppRPE/BM 3D morphology in terms of its 3D angle and scanning tilt angles. Results showed that the variations of the ppRPE/BM layer angle across radial scans were well explained by its 3D angle and scanning tilt angles. The ppRPE/BM layer 3D angle was reversely fitted from the measured ppRPE/BM layer angles across radial directions with application to six eyes from four patients, who underwent medically necessary lumbar puncture. The fitted curve from our mathematical model matched well with the experimental measurements ( R 2 > 0.9 in most cases). This further validated our mathematical model. The proposed model in this study has elucidated the variations of ppRPE/BM layer angle across 2D radial scans from the perspective of the ppRPE/BM layer 3D morphology. It is expected that the ppRPE/BM layer 3D angle developed in this study could be further exploited as a new biomarker for the optic disc. Graphical abstract

White light-emitting diodes (WLEDs) hold great promise in lighting, display, and visible light communication devices, and single-component white emission carbon quantum dots (SCWE-CQDs) as the key component of WLEDs have many outstanding advantages. However, rapid and efficient synthesis of SCWE-CQDs with high photoluminescence quantum yield (PLQY) and stability remains challenging. Here, we report a novel solvent engineering strategy to obtain highly photoluminescent SCWE-CQDs by controlling the dilution ratios between N,N -dimethylformamide (DMF) and pristine red carbon quantum dots (RCQDs) solution. By optimizing synthesis conditions, the relative PLQY of the SCWE-CQDs solution reached 53%. Morphological, structural, and optical property characterizations indicate that the combined action of the hydrogen bond (HB) effect and the size effect leads to the blue shift of RCQDs, but the HB effect is more dominant than the particle size in causing large spectral shifts. In addition, the WLEDs with high color rendering index of 89 and remarkable reliability were obtained based on the highly photoluminescent SCWE-CQDs. This facile solvent engineering approach for synthesizing tunable emission CQDs will promote the progress of carbon-based luminescent materials for applications in optoelectronic devices.

With the emerging of sustainability, the fabrication of effective and eco-friendly agents for rubber industry has attracted extensive attention. In this study, a novel and nontoxic titanium dioxide-based vulcanization accelerator (xanthate-modified nanotitanium dioxide (TDSX)) with excellent antibacterial performance, for the first time, was synthesized under the catalyst of ceric ammonium nitrate. Notably, the thermal stability of xanthate was greatly enhanced after being grafted on titanium dioxide (TiO 2 ) nanoparticles, in which the activation energy was increased from 6.4 to 92.5 kJ/mol, enabling the obtained TDSX with multiple functions, mainly consisting of fabulous vulcanization-promoting effects, reinforcing effects, antibacterial properties, and anti-ultraviolet aging effects for natural rubber (NR). Simultaneously, the TDSX can be effectively and uniformly dispersed in the rubber matrix along with the developed interface interaction between TDSX particles and rubber matrix. Compared to the traditional accelerators 2-mercaptobenzothiazole (M) system, the tensile strength and the tearing strength of NR/TDSX was improved by 26.3 and 40.4%, respectively. Potentially, our work for preparing green vulcanization accelerator can provide a new design strategy for multifunctional high performance elastomer materials. Graphical abstract

Impact drop weight tests, rapid chloride migration coefficient tests, single-sided freeze–thaw tests, and mechanical property tests were performed to investigate the effect of the steel fiber (SF) content on the impact resistance and durability of concrete containing nano-SiO 2 (NS). A fixed NS content of 3% and six SF contents in a range of 0–2.5% by volume were used. The impact resistance was measured based on the number of blows (N1, N2) and the impact energy. The durability of concrete includes its freeze–thaw resistance and chloride ion penetration resistance, which were appraised by the chloride ion diffusion coefficient (CDC) and relative dynamic elastic modulus (RDM), respectively. The ductility ratio was used to predict the impact resistance of concrete containing NS with different SF contents, and a linear relation between this ratio and the impact energy ( R 2 = 0.853) was found. The experimental results indicated that SF could greatly improve the impact resistance of concrete. The addition of 2.0% SF increased N1 and N2 by 106 and 169%, respectively. In addition, an appropriate SF content significantly improved the durability of the concrete, including its frost resistance (especially in the middle and late freezing–thawing cycles) and chloride ion penetration resistance. An SF content of 1.5% was the optimum, decreasing the CDC of nano-concrete by 17.1% and minimizing the RDM loss. Moreover, the 1.5% SF content increased the compressive strength of concrete containing NS by 18.5%, whereas an SF content of 2.0% increased the splitting tensile strength and flexural strength by 77 and 20%, respectively. Furthermore, when the SF content exceeded a certain value, the improvement effect on these properties began to decrease and even became negative.

In this study, ultrasonically driven biosynthesis of zinc oxide nanoparticles (ZnO NPs) using Swietenia macrophylla seed ethyl acetate fraction (SMEAF) has been reported. X-ray powder diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) analyses confirmed the presence of a pure hexagonal wurtzite structure of ZnO. Field emission scanning electron microscope images revealed the formation of uniquely identifiable uniform rice-shaped biologically synthesized ZnO SMEAF particles. The particle sizes of the biosynthesized NPs ranged from 262 to 311 nm. The underlying mechanisms for the biosynthesis of ZnO SMEAF under ultrasound have been proposed based on FTIR and XRD results. The anticancer activity of the as-prepared ZnO SMEAF was investigated against HCT-116 human colon cancer cell lines via methyl thiazolyl tetrazolium assay. ZnO SMEAF exhibited significant anticancer activity against colon cancer cells with higher potency than ZnO particles prepared using the chemical method and SMEAF alone. Exposure of HCT-116 colon cancer cells to ZnO SMEAF promoted a remarkable reduction in cell viability in all the tested concentrations. This study suggests that green sonochemically induced ZnO NPs using medicinal plant extract could be a potential anticancer agent for biomedical applications.

Hardness is one of the important mechanical properties of high-temperature structural ceramics and their composites. In spite of the extensive use of the materials in high-temperature applications, there are few theoretical models for analyzing their temperature-dependent hardness. To fill this gap in the available literature, this work is focused on developing novel theoretical models for the temperature dependence of the hardness of the ceramics and their composites. The proposed model is just expressed in terms of some basic material parameters including Young’s modulus, melting points, and critical damage size corresponding to plastic deformation, which has no fitting parameters, thereby being simple for materials scientists and engineers to use in the material design. The model predictions for the temperature dependence of hardness of some oxide ceramics, non-oxide ceramics, ceramic–ceramic composites, diamond–ceramic composites, and ceramic-based cermet are presented, and excellent agreements with the experimental measurements are shown. Compared with the experimental measurements, the developed model can effectively save the cost when applied in the material design, which could be used to predict at any targeted temperature. Furthermore, the models could be used to determine the underlying control mechanisms of the temperature dependence of the hardness of the materials.

Based on the results of the previous experiment, this article studied the acoustic emission (AE) signals released during the crystallization of salicylic acid to establish the relationship between the AE signal and the particle size. A tremendous amount of acoustic data was analyzed using time–frequency domain analysis methods in order to extract the valuable contents. Based on the diffusion theory, the vibratory model between the AE signal and the crystal particle size was established. This article mainly studies the process of small particles diffusing to the growth point by impact, adding to the lattice, and the crystal releases energy. The impact of the growth unit on particle aggregate is equivalent to a linear elastic vibration system with one end fixed and the other end free. The vibration frequency is 200–355 kHz when the particle size is between 600 and 1,100 µm. The calculated vibration frequency is in good agreement with the measured frequency. Graphical abstract

Helical carbon nanotubes (HCNTs) are a kind of potential microwave absorption (MA) material due to their chiral and dielectric properties. However, the inert surface property makes HCNTs with poor polarization loss ability and impedance matching characteristic, which impedes its ability in attenuating microwaves. Herein, the HCNTs were modified with defects and functional groups on the surface to optimize their electromagnetic response characteristics and achieve an enhanced MA performance. The experimental results show that the modified HCNTs (F-HCNTs) exhibit a significant enhancement in MA performance when compared with HCNTs. The minimum reflection (RL min ) loss of F-HCNTs reaches −45.4 dB at 17.5 GHz at a thickness of 2.4 mm and the bandwidth of RL < −10 dB is 3.6 GHz (from 14.4 to 18.0 GHz). Further analysis demonstrates that proper modification of HCNTs leads to enhanced dielectric loss ability and optimized impedance matching characteristics, both of which are beneficial to the MA performance of HCNTs. Graphical abstract

The mechanical properties of basalt fiber-reinforced epoxy composites (BFRPs) are significantly dependent on the interfacial adhesion between basalt fibers (BFs) and the epoxy matrix. In this study, we proposed a simple and efficient method for deep and stable penetration of BFs into the epoxy matrix through dry-ozone treatments. To confirm the efficiency of the proposed method, BFRPs were fabricated using two types of composites: untreated BFs and dry-ozonized BFs in varying amounts, and the optimum amount of BFs for all the composites fabricated in this work was 60 wt%. With the addition of this amount of dry-ozonized BFs, the interlaminar shear strength and fracture toughness of the composites were enhanced by 21.2 and 23.2%, respectively, as compared with untreated BFs. The related reinforcing mechanisms were also analyzed, and the enhanced interfacial adhesion was mainly attributed to the mechanical interlocking effect. This approach shows that the dry-ozone treatment of BFs is a simple and efficient method for the preparation of BFRPs with excellent interfacial adhesion, which can be a potential application in the auto parts industry.

This contribution investigates chlorine (Cl) interaction with the Fe(100) surface, with a focus on governing adsorption energies and geometrical features at the nanoscale using the density functional theory (DFT) approach. The Cl/Fe(100) system can be considered as a building block to create nanosystems with specific and desired electronic, material, mechanical, or environmental properties. We report adsorption energies, surface relaxations. and buckling distances for Cl adsorbed as a function of Cl coverage. The computational DFT framework employs a vdW-DF functional with coverages varying from 0.25 to 1 ML. Adsorption at a bridge site with coverage of 0.5 ML appears to be the most preferred site, with an adsorption energy of −4.44 eV. For all coverages, Cl adsorption at the bridge and hollow sites incurs slightly higher adsorption energies than adsorption at the top (T) site. The potential energy surface (PES) for the dissociation of a Cl molecule over the Fe(100) surface was calculated. Dissociative adsorption of the Cl molecule on Fe(100) ensues via a modest activation barrier of only 0.58 eV in a noticeably exothermic reaction of 2.94 eV. In agreement with experimental observations, the work function decreases upon Cl addition in reference to the clean iron surface. The electronic interaction between Cl and the Fe(100) surface was examined by calculating the differential charge density distribution of the most stable structure (B-0.5 ML). The vdW-DF interactions increase the adsorption energies and reduce the equilibrium distances when compared with the corresponding results from plain DFT.

In this paper, we use a simple and cheap approach for the synthesis of herceptin-conjugated graphene biosensor to detect the HER2-positive breast cancer cells. The bifunctional graphene-herceptin nanosheets are prepared from graphite by a simple ultrasonic-mediated technique. The prepared protein-mediated graphene is fully characterized. The results show the exfoliation of graphene layers in herceptin solution. Moreover, herceptin is effectively conjugated into the surface of graphene nanosheets. The synthesized herceptin-conjugated graphene is applied for breast cancer detection. The linear range of this biosensor is 1–80 cells, which is significant. The biosensor shows an excellent selectivity performance for detection of HER2-positive cancer cells. Likewise, the stability and functionality of the biosensor is about 40 days. Based on the results, this device is a promising candidate for rapid and selective detection of cancer cells.

Ultrahigh-performance concrete (UHPC) has been increasingly employed for infrastructure and building structure, thanks to its excellent durability and exceptional mechanical properties; however, improving its relatively low flexural strength remains a challenging issue. This study presents an experimental investigation on improving the compressive strength and flexural strength of UHPC by employing sustainably synthesized graphene oxide (GO). The content of micro steel fibers (MSFs) for the UHPC ranges from 0.5 to 1.5% by volume of concrete. For each level of MSFs addition, the dosage of GO added is from 0.00 to 0.03% by mass of cement. The results indicate that the electrochemical (EC) method to synthesize GO is greener, safer, and lower in cost for construction industry. And the compressive strength of UHPC is slightly improved, while its flexural strength is significantly increased from 33 to 65%, demonstrating that the incorporation of GO can be an effective measure to enhance the flexural strength of UHPC under standard curing and steam curing. This can be associated with the improvement in bond strength between the MSFs and the matrix contributed by the improved interfacial microstructure, the higher friction increase, and the mechanical interlock at the interface between the MSFs and the bulk matrix, thanks to the addition of GO. Graphical abstract

Graphene (G) and graphene oxide (GO) have been shown to significantly improve the mechanical properties of cement-based materials. In this study, the effect of the G/GO on cement hydration was investigated. First, the zeta potential of G/GO in simulated solutions was tested, and the interaction between G/GO’s surface and Ca 2+ was explored. Subsequently, scanning electron microscopy was used to observe the morphology of C–S–H nucleation and growth on the cement surface in the cement paste containing G/GO. Furthermore, XRD and TGA analyses were carried out on the hydration products of the sample. At last, isothermal calorimetry was applied to investigate the influence of G/GO on the early hydration of cement. The results showed that the addition of G/GO significantly accelerates C–S–H nucleation and growth on the cement surface. It is indicated that the high mobility ions derived by G/GO in the cement paste dominate the reason for the accelerated hydration of cement. The presence of G, especially GO, facilitates the mobility of ions, especially Ca 2+ , thus enhances the interaction between the cement surface and the ions. This strong interaction promotes the C–S–H nucleation and growth, and therefore, the hydration of the cement. Graphical abstract (1) GO has a strong interaction with Ca 2+ . (2) G/GO accelerates C–S–H growth. (3) High mobility ions derived by G/GO facilitate hydration.

The present study focused on the preparation of microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC) from pineapple ( Ananas comosus L.) leaves using chemical treatments followed by acid hydrolysis. Pineapple leaves could be used in medical applications such as drug delivery carriers. Advanced spectroscopy techniques such as Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze the physical, chemical, and morphological features of the isolated MCC and NCC; the results indicated the needle-shaped form of nanostructures with good purity and high crystallinity index of 75.00 and 76.38%, respectively. In addition, inhibition of the treated MRC-5 cells with all the samples revealed that the percentage of cell viability was less than 30%, which is an interesting finding given their role in the cytotoxicity effect of MCC and NCC. It appears that MCC and NCC derived from pineapple leaves have lower toxicity. As a result, the developed MCC and NCC can be used in pharmaceutical applications as a novel drug delivery system. Molecular docking was performed to understand the non-bonding interaction of cellulose with human acid-beta-glucosidase (β-Glc) (PDB: 1OGS). The docking result shows that cellulose unit docked within the active pocket of the enzyme by forming hydrogen bonds against ASN19, THR21, and VAL17 with distances of 2.18, 1.93, and 2.92 Å, respectively, with binding energy (−5.0 kcal/mol) resulting in close interaction of cellulose unit with the receptor.

Calcium silicate hydrate (C–S–H) is the main product of cement hydration, which forms the microstructure of cement via the stacking of basic nanocrystals or gel units, and has a substantial influence on the mechanical performance of cement. Tetrahedron chains of silicon oxide form the main nanoscale structure of basic C–S–H units. Evaluation on the nanostructure of these tetrahedron chains facilitates to understand the source of cement strength. This article first introduced the atomic force microscopy-infrared spectroscopy (AFM-IR) technique into evaluating the nanostructure of C–S–H. The nano infrared spectroscopy of stacking C–S–H nanograins and tetrahedron spatial distribution mapping was obtained. The results demonstrate that the relative quantity of tobermorite-like and jennite-like units in C–S–H nanograins can be analyzed by AFM-IR. The stacking between C–S–H particles is facilitated to a large extent by silicate ( SiO 4 2 − {\text{SiO}}_{4}^{2-} ) tetrahedron chains formed of three tetrahedrons bridged by two oxygen atoms ( i.e. , Q 2 chains), and there are Q 2 chains acting as bridges between C–S–H particles. The proportions of different types of Q 2 chains available for facilitating C–S–H particle stacking vary at the nanoscale. AFM-IR spatial mapping demonstrate that the orientations of these Q 2 chains are not evenly distributed. These findings provide experimental information of the stacking C–S–H gaps. Graphical abstract

Recycled aggregate concrete (RAC) is an environmentally friendly material. However, owing to inherent characteristics of the recycled aggregate (RA), it is difficult to promote and apply it in structural engineering. Silica fume (SF) and nano-silica (NS) have different characteristics as additives for RAC. It has been proven that adding SF only enhances the strength of RAC at a later stage, and NS can improve the early strength of RAC owing to its high pozzolanic activity. In this study, to further improve the properties of RAC, two types of additives were combined into RAC, which was named SF-NS-modified RAC (SSRAC). Compression and split tensile tests were conducted to analyze the mechanical properties of SSRAC at different curing ages. The results indicated that the combined addition of NS and SF improved the performance of RAC at early and later curing ages. Scanning electron microscopy and X-ray diffraction analyses were performed to explore the NS and SF mechanism. The results indicated that SF and NS in SSRAC had a good pozzolanic effect and underwent a secondary hydration reaction with calcium hydroxide to increase the production of calcium silicate hydrate, resulting in an increase in the properties of the interface transition zone. Finally, 6% SF and 2 or 3% NS are recommended as supplementary cementitious materials for RAC. Graphical abstract

To evaluate the safety of stent malapposition of corrodible nitride iron stent as biodegradable cardiovascular implants, a total of 108 stents were implanted into the abdominal aortas, iliac arteries, and iliac artery bifurcations of 36 New Zealand white rabbits separately. Each rabbit was implanted with three stents. After a follow-up period of 3 months, no thrombus and embolism were found in local and downstream vessels. And no other adverse events occurred either. Stent strut covered by endothelial layer started to show signs of degradation, while struts exposed to bifurcated blood flow covered by a layer of tissue and no rust particle was found on the surface. Also, there were no traces of thrombosis and traces of excess inflammation. The authors conclude that the risk brought by stent malapposition in less than 9 months is acceptable.

The hazard-free treatment of Cr( vi ) ions is critical in modern industry. Photocatalytic reduction and detoxification are high-potential strategies. Photocatalysts with high efficiency, low cost, environmental friendliness, and easy mass products are required. In this study, we report a facile strategy using triethanolamine (TEOA) as a capping ligand to modify the surface of ZnO nanospheres. The experimental and theoretical results reveal that the presence of TEOA on the surface was beneficial for electron enrichment on Zn and hole transfer to TEOA and can photocatalytically reduce Cr( vi ) by almost 100% in 5 min. The photocatalytic property of TEOA-modified ZnO could be renewed by the reabsorption of TEOA in solution. The great sedimental properties benefit photocatalyst recycling and renewal, which also provides high potential for water pollution and environmental emergency responses applications.

Digital microfluidics (DMF) is a versatile fluid handling tool that is widely used in the biochemical field. There are very high requirements for the volume of single droplet in many biochemical applications. Droplet dispensing and splitting are two main operations to generate a single droplet in DMF. Therefore, the generation of droplets with high volume precision and accuracy in the two droplet operations is one of the keys to the efficient application of DMF in biochemical analysis. We have developed a novel droplet dispensing and splitting scheme where electrode geometry is optimized. The liquid column can contract in a regular shape, which keep the neck shape uniform and stable, and the position of pinch-off point was fixed; meanwhile, the liquid tail is eliminated before pinching off, so that the precision and accuracy of droplet volume were greatly improved. The increase in the radius of the cutting electrodes elongated the droplet neck and increased the neck curvature at the pinch-off point, which further effectively improved the precision and accuracy of droplet volume. The optimized droplet splitting scheme can also be applied to the droplet splitting with unequal volume effectively.

As biodegradable orthopedic implant materials, magnesium alloys have been attracted enough attentions recently. However, too fast degradation in vivo , limited biocompatibilities, and insufficient antibacterial properties are three main challenges at present. In order to solve these problems, a multifunctional composite coating of Chi(Zn/BMP2)/HA was constructed on AZ31B magnesium alloy surface, successively by the alkali heating treatment, self-assembly of 16-phosphonyl-hexadecanoic acid, in situ immobilization of Chi(Zn/BMP2) (chitosan, zinc ions, and bone morphogenetic protein 2), and the deposition of HA (hydroxyapatite). The results of ATR-FTIR (attenuated total reflection Fourier transform infrared spectrum) spectra and elemental compositions confirmed that 16-phosphonyl-hexadecanoic acid, Chi(Zn/BMP2), and HA were successfully immobilized on the surface. Compared with Mg, Mg-OH, Mg-16, and Mg-Chi(Zn/BMP2), Mg-Chi(Zn/BMP2)/HA with the concave–convex structure surface significantly enhanced the hydrophilicity and corrosion resistance. On the other hand, Mg-Chi(Zn/BMP2)/HA coating also showed excellent biocompatibilities, which not only significantly promoted the osteoblast adhesion and proliferation, but also upregulated ALP and OCN expression of osteoblasts. Furthermore, due to the synergistic antibacterial effect of zinc ions and chitosan, Mg-Chi(Zn/BMP2)/HA showed a good antibacterial property against Escherichia coli ( E. coli ). Therefore, it can be said that the method used in this work has a good application prospect in improving the corrosion resistance, biocompatibility of magnesium alloys, and inhibiting infections against E. coli .

This study focused on experimental and numerical investigations into the low-velocity impact behavior of epoxy resin matrix syntactic composites with embedded hollow glass microspheres (HGMs) and multiwalled carbon nanotubes (MWCNTs). The synergistic effects of HGMs and MWCNTs on the mechanical properties of epoxy resin composites were improved by applying amine and acid treatments to HGMs and MWCNTs, respectively. The influence of the MWCNT content and the applied impact energy on the impact responses and compression strength after the impact of these syntactic foam panel samples were discussed. The results indicated that modifying HGMs and MWCNTs contributed to improving the energy absorption and the strength retention factor (SRF) of these panels and the SRF increased with increased MWCNT content. Moreover, multiscale finite-element (FE) models were developed to simulate panel impact behavior, and modeling results were compared with experimental data. Then, the verified FE model was used to analyze the influence of CNT types (helical CNTs vs MWCNTs) and the diameter-to-thickness ratios of HGMs. This study provided a theoretical basis and design reference for a novel lightweight composite material subjected to low-velocity impact, which could be applied as a core material for sandwich structures in aerospace, marine engineering, transportation, and civil infrastructures. Graphical abstract

On the basis of the finite element theory, in this study, a theoretical design and simulation practice to carry out steady-state static analysis, structural dynamics analysis, and electromagnetic interferencecharacteristics analysis on smart light poles, is combined. On this basis, a design of modular weight reduction and cost reduction was proposed, which realized the multi-objective parameter optimization of the smart light pole. The simulation results show that the mass of the optimized light pole can be reduced by 14.2%, and the material cost can be reduced by 14.7%. At the same time, the comprehensive performance of the optimized smart light pole can still meet the design requirements of the industry standards. The research results provide a reference for the lightweight design and the comprehensive analysis of the smart light pole in the future.

In this article, the flower-like, urchin-like, and rod-like ZnOs were synthesized by a convenient atmospheric hydrothermal method. The crystalline structures, morphologies, exposed crystal faces, and specific surface areas of the as-prepared ZnO samples were analyzed. Rhodamine B (RhB) was used as the simulated pollutant to evaluate the photocatalytic performance of the ZnO nanostructures. The flower-like ZnO prepared by controlled hydrothermal method at room temperature for 2 h displayed highest specific surface area and exposed more high active { 2 1 ¯ 1 ¯ 0 } \{2\bar{1}\bar{1}0\} facets compared to the other two morphologies of ZnO. In addition, within 2 h of the photocatalytic reaction, the flower-like ZnO results in 99.3% degradation of RhB and produces the most hydroxyl radicals (˙OH) 47.83 μmol/g and superoxide anions (˙ O 2 − {\text{O}}_{2}^{-} ) 102.78 μmol/g. Due to the existence of oxygen vacancies on the surface of { 2 1 ¯ 1 ¯ 0 } \{2\bar{1}\bar{1}0\} facets, the flower-like ZnO can efficiently catalyze the production of active oxygen, leading to the improvement in the photocatalytic efficiency.

Poly(vinylidene fluoride) (PVDF) and its copolymers exhibit excellent piezoelectric properties and are potential materials for high efficiency energy harvesting devices. In this study, poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) films are prepared by the solution casting method. The prepared film is then subjected to mechanical stretching and poling process. By adjusting the temperature of the poling process and the elongation ratio of the mechanical stretching process, the relative content of β-phase F (β) increases significantly, leading to high piezoelectric performance. The maximum output voltage of the PVDF-HFP films poled at 40°C reaches 3.67 V, 71% higher than that of the films poled at room temperature. Fourier transform infrared spectroscopy analysis (FTIR), XRD (X-ray diffraction), and differential scanning calorimetry are used to investigate the influences of mechanical stretching and poling process on the crystal structure to discover the enhancement mechanism. This work provides a straightforward and low-cost route to prepare high piezoelectric PVDF-HFP-based materials.

In this work, in situ magnesium-based composite composed of nanoscale magnesium oxide (MgO), prepared by spark plasma sintering, shows significant plasticity and high strain hardening. During the strain-hardening stage, the incremental work-hardening exponent shows drastic fluctuations due to the pile-up and release of dislocations. The dislocation pile-up at the interface makes it possible to form dislocation cells. Mixed dislocations can be generated within the cells surrounding the MgO particles, which can interact with the stress field and effectively hinder the movement of dislocations, leading to an increase in dislocation density. What is more, grain boundaries have higher elastic modulus and hardness, which may lead to the appearance of microcracks and eventually intergranular fractures. Our results may shed some light on understanding the role of MgO particles in influencing the mechanical properties of Mg alloys and Mg-based composites, especially in work hardening. Graphical abstract

Early diagnosis of cancer has become one of the effective ways to prevent and treat cancer. At present, magnetic resonance imaging (MRI) diagnosis based on nanosized iron oxide with no toxicity and excellent biocompatibility has attracted much attention. But the poor stability of magnetic fluid (MF) is becoming more and more prominent. In view of the poor stability of MF, the dodecanethiol-poly(methacrylic acid) (DDT-PMAA) as an outer shell was prepared for the MFs (Fe 3 O 4 @DDT-PMAA MF) to improve the stability. We also compared the amount of reactants, the ratio of reactants, and the reaction temperature, and finally screened out the best reaction conditions, so as to get more stable products. The stability of the system was studied by visual observation, stability index ( I ), and magnetic weight change. The results demonstrated that Fe 3 O 4 @DDT-PMAA can be stable for more than 60 days. The T 1 mapping image showed that the longitudinal relaxivity ( r 1 ) value was 6.9 mM −1  s −1 (1.5 T, room temperature), which was higher than the commercial contrast agent SHU-555 ( r 1 = 2.9 mM −1  s −1 ), but the transverse relaxivity ( r 2 ) value accounted for 64.48% of the commercial contrast agent Feridex ( r 2 = 67.8 mM −1  s −1 , 1.5 T, room temperature) because the outermost layer was encapsulated by a polymer. In addition, the imaging effect was more vivid and there was almost no background interference of T 1 - and T 2 -weighted images in vivo , which indicated that the Fe 3 O 4 @DDT-PMAA MF exhibited excellent potential in MRI applications.

The biogenic synthesis of zinc oxide nanoparticles (ZnO NPs) with pinecone extract (PCE) as a reducing agent and antibacterial agent was explored. The current study aims to investigate the biosynthesis of ZnO NPs and their effect on photocatalytic dye degradation and antimicrobial properties. The physical, chemical, and morphological properties of biogenic ZnO NPs synthesized using PCE were investigated using advanced spectroscopy techniques such as Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy, transmission electron microscopy (TEM) analysis, selected area electron diffraction (SAED), and X-ray diffraction (XRD) techniques. The photocatalytic degradation of methylene blue was measured spectrophotometrically using biogenic ZnO NPs as nanocatalysts, and decolonization of solution indicates dye degradation gradually as exposure duration increases. The antimicrobial properties of ZnONPs against the tested pathogenic strains were demonstrated using the disc diffusion method. The antimicrobial efficacy of ZnONPs was further explained using molecular docking analysis. Confirmation of the lowest binding energy was used to predict receptor binding site with NPs in order to understand the mechanistic approach. ZnONPs are likely to interact with pathogens via mechanical enfolding, which could be one of the major toxicity actions of ZnONPs against strains. Furthermore, the nontoxicity and biocompatibility of ZnO NPs were studied, revealing impressive hemocompatibility with red blood cells (RBCs) and no significant toxicity to Brine shrimps at lower ZnONP concentrations.

Due to the need for structures with refined properties to bear against different loading conditions, recently, carbon nanotubes (CNTs) have been used widely to reinforce them. The extremely high stiffness of CNTs makes them significant as one of the best reinforcements to improve the mechanical behaviors of structures. This work focuses on microbeam buckling response with an initial curvature that includes three layers. The mid-layer that is known as the core is constituted of functionally graded porous (FGP) materials and two CNT-reinforced composite skins are bonded to the core to integrate it. The whole structure is affected by the hygrothermal environment and springs and shear layers are put below it. For the first time, for such a structure, a refined shear deformation theory (RSDT) as a higher-order theory that considers thickness stretching effect in polar coordinates is used that presents more accurate results, especially for deeply curved beams. Modified couple stress theory (MCST) in combination with the virtual displacement principle is utilized to establish the governing equations. The obtained results demonstrate the significance of porosity percentage and CNTs’ addition to the skins on the critical nanotubes buckling load. Also, the different behaviors of the microstructure at various temperatures are analyzed and discussed in detail.

In order to clarify the effect of thermal aging on the nano-stabilized modified asphalt binder, TINUVIN 770 (T770) hindered amine light stabilizer of nanoscale was selected as aging modifying agent to prepare modified asphalt. The impact of thermal aging on the rheological properties of T770-modified asphalt was investigated using dynamic shear rheological test of frequency sweep and multiple stress creep recovery test. The surface roughness variation of T770-modified asphalt was characterized by using atomic force microscope throughout the thermal aging process. Furthermore, the typical morphology and parameter features of T770-modified asphalt were identified. The results showed that with the extension of thermal aging time, the high temperature rutting resistance of T770-modified asphalt was improved, while the unrecoverable creep compliance was degraded. When the thermal aging time exceeded 6 h, the bee structure appeared on the surface of T770-modified asphalt. Meanwhile, with the increase in thermal aging time, the special structure formed on the surface of asphalt gradually became smaller. The surface fluctuation difference of T770-modified asphalt reflected the better thermal aging resistance property of T770-modified asphalt than 70# asphalt.

Particles have been demonstrated to toughen epoxy resins, especially for fiber-reinforced epoxy composites, and core/shell particles are one of them. It is known that not all particles toughen the same but most evaluations are through experimentation, and few studies have been conducted to accurately predict the particles’ toughening effect or guide the design of effective particles. In this study, efforts were made to find the control factors of core/shell particles, primarily interfacial compatibility and degree of dispersion, and how to predict them. Nanocomposites were fabricated by incorporating core/shell nanoparticles having various shell polymer compositions, especially their polarities. Their compatibility was estimated using a novel quantitative approach via adopting the theory of Hansen solubility parameters (HSP), in which the HSP of core/shell nanoparticles and the epoxy matrix were experimentally determined and compared. It was found that the HSP distance was a good predictor for particle dispersion and interfacial interaction. Particles having a small HSP distance ( R a ) to the epoxy resin, represented by the polybutylacrylate core/polymethyl methacrylate shell particle having the smallest R a of 0.50, indicated a uniform dispersion and strong interfacial bonding with the matrix and yielded outstanding toughening performance. In contrast, polybutylacrylate core/polyacrylonitrile shell particle having the largest HSP distance (6.56) formed aggregates and exhibited low interfacial interaction, leading to poor toughness. It was also demonstrated that HSP can provide an effective strategy to facilitate the design of effective core/shell nanoparticles for epoxy toughening. Graphical abstract

In this article, the structural and nanoscale strain field of the α/β phase interface layer in Ti80 alloy were studied by using high-resolution transmission electron microscopy (HRTEM) and geometric phase analysis (GPA). The α/β interface layer was observed in forged and different annealed Ti80 alloys, which is mainly composed of lamellar face-centered cubic (FCC) phase region and α′ + β region. The FCC phases between α and β phases show a twin relationship, and the twinning plane is ( 1 1 ¯ 1 ) (1\bar{1}1) . The orientation relationship of the β phase, the α phase, and the FCC phase is (110) β //(0001) α // ( 1 1 ¯ 1 ) (1\bar{1}1) FCC and [ 1 ¯ 11 \bar{1}11 ] β //[ 2 1 ¯ 1 ¯ 0 2\bar{1}\bar{1}0 ] α //[011] FCC . The nanoscale strain field of FCC + α and β + α′ regions was analyzed by using the GPA technology. The FCC + α region shows more significant strain gradient than the α′ + β region, and ε FCC > ε α , ε α′ > ε β . The influence of element addition on the formation mechanism of the FCC phase was discussed. The addition of Zr promotes the formation of the FCC phase by inducing lattice distortion and reducing the stacking fault energy of the α phase. In addition, the Al element forms an obvious concentration gradient around the interface layer during the cooling process of the alloy, which provides a driving force for the formation of the FCC phase. Graphical abstract

Corrosion and icing are common problems in aerospace and wind power fields. In order to improve the thermal and hydrophobic properties of epoxy-based anticorrosive coatings and expand the application in various working environments, the modified graphene oxide (GO) was introduced into the epoxy-based anticorrosive coatings to prepare GO/polyvinyl butyral/epoxy resin nanocomposite coatings. The preparation process of nanocomposite coating was optimized by response surface method. Through heat transfer experiment and contact angle experiment, the fitting model of influence factors and response values were established, and the response surface was optimized with heating rate and contact angle as response value. It is reported that the heating rate of the optimum parameter is 0.218°C/s, and the contact angle is 85.757°. The maximum error of the optimized response values verified by the coating experiment is 8.58%, which indicates that the reliability of the RSM optimization result is high. The optimization results of the preparation process parameters can meet the requirements of the nanocomposite coatings with high thermal and hydrophobic properties. Graphical abstract

To solve the problem of the pavement being aged due to the influence of temperature, light and other environmental factors are brought in service. Nano-CaCO 3 surface was activated by 6% KH-550, and nano-ZnO surface was activated by 6% aluminate. Nano-CaCO 3 /nano-ZnO/SBR composite-modified asphalt was prepared. The optimum proportion of composite-modified asphalt was determined by orthogonal test. The influence of modifiers on asphalt pavement performance was comprehensively studied. The microstructure of composite-modified asphalt was characterized by scanning electron microscopy and infrared spectroscopy. The mechanism of composite-modified asphalt was analyzed. The results show that the optimum combination of composite-modified asphalt is 4% nano-CaCO 3 + 5% nano-ZnO + 4% SBR, the aging performance of the composite-modified asphalt is reduced by 6.9%, and the viscosity is increased by 14.6–23.1%. The complex shear modulus is increased by 24.1% at 82°C, the stiffness modulus is decreased, on average, by 21.1%. and the creep curve slope is increased by 9% on average. In the meantime, during the preparation process of composite-modified asphalt, it mainly occurred due to chemical reaction with surface-modified nanomaterials and physical change with SBR polymer materials.

Three novel three-dimensional orthorhombic carbon phases are proposed based on first-principles calculations in this work. These phases possess dynamic stability and mechanical stability and are theoretically more favorable in energy compared to most other carbon allotropes. The hardness levels of o P-C 16 , o P-C 20 , and o P-C 24 are 47.5, 49.6, and 55.3 GPa, respectively, which are greater than those of T10, T18, and O12 carbon. In addition, although o P-C 16 , o P-C 20 , and o P-C 24 are metals, their ideal shear strengths are also greater than those of common metals such as Cu, Fe, and Al. Due to p y electrons crossing the Fermi level, o P-C 16 , o P-C 20 , and o P-C 24 show metallicity, and their charge densities of the band decomposition suggest that all the conductive directions of o P-C 16 , o P-C 20 , and o P-C 24 are exhibited along the a - and b -axis, similar to C 5 . Graphical abstract The crystal structures of o P-C 16 , o P-C 20 , and o P-C 24 .

This study investigated the emulsifying properties of a protein–polysaccharide hybrid nanoconjugate system comprising cellulose nanocrystals (CNC, 1% w/v) and soy protein isolate at various concentrations (SPI, 1–3% w/v). The average particle size of the nanoconjugate increased, and the zeta potential decreased when 3% (w/v) of SPI was used. The contact angle and thermal stability of CNC improved with the conjugation of SPI. Upon Pickering emulsification, 0.5% (w/v) of CNC–SPI nanoconjugate as particle stabilizer was sufficient to obtain stable emulsions. The CNC–SPI1 formulation (CNC to SPI, 1:1) provided the emulsion with the smallest droplet size and higher emulsifying activity. Intriguingly, ultrasound (US) pre-treatment on nanoconjugates before emulsification significantly reduced the size of the emulsion. The rheological assessment demonstrated that the CNC–SPI-stabilized emulsions exhibit shear thinning behavior at a lower shear rate and shear thickening behavior at a higher shear rate, indicating the interruption of existing attractive interactions between the CNC particles. All emulsions exhibited higher elastic modulus ( G ′) than viscous modulus ( G ″), suggesting high viscoelastic properties of the emulsions. This study demonstrates that CNC–SPI nanoconjugate with optimum protein to polysaccharide ratio has great potential as a natural particle stabilizer in food and nutraceutical emulsion applications. Graphical abstract

This paper takes nano-SiCp/Al–7Si matrix composites prepared by powder metallurgy as the research object. With the help of advanced microstructure characterization techniques and performance analysis methods, the effect of nano-SiCp volume fraction on the microstructure and properties of composites is systematically studied. Based on optimizing the volume fraction of nano-SiCp, the thermal deformation behavior of the composites is investigated. It was found that with an increase of nano-SiCp content, the distribution uniformity of nano-SiCp decreases gradually. And because the surface of nano-SiCp is easy to adsorb gas and the aggregated distribution of nano-SiCp is not conducive to the sintering process, the density of the composites shows a gradually decreasing trend. The hardness of the composites tends increasing gradually, and the increase in amplitude gradually decreases. Due to the addition of nano-SiCp, there are many interfaces between SiCp and Al matrix, and cracks are prone to initiation and expansion at the interface. Therefore, as the volume fraction of nano-SiCp increases, the elongation of nano-SiCp/Al–7Si composites gradually decreases. When the volume fraction of nano-SiCp is 2%, the strength of the composites reaches the maximum value of 217 MPa. Compared with the Al–Si alloy without adding nano-SiCp, the results increased by 37.3%. In addition, with the decrease of strain rate and the increase of deformation temperature, the dislocation density in the composites gradually decreases, and the dynamic softening progresses more fully. The dynamic recrystallization nucleation mechanism mainly includes the subcrystal merging mechanism and the grain boundary bowing mechanism.

To meet the requirements of automatic production, a new type of green BAl88Si cored solder was developed. The lap brazing experiments were carried out with copper and aluminum as brazing substrates. The microstructure, phase composition, and corrosion behavior of solder joint interface were studied by field emission scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, electron backscattering diffraction, tensile testing machine, and electrochemical workstation. The results show that the brazing joint of Cu/BAl88Si/Al is metallurgical bonding, and the brazing joint of Cu/BAl88Si/Al is composed of Cu 9 Al 4 , CuAl 2 , a-Al, (CuAl 2 + a-Al + Si) ternary eutectic. In addition, there is no obvious preference for each grain in the brazing joint, and there are S texture {123}<634>, Copper texture {112}<111>, and Brass texture {110}<112>. The interface of Cu 9 Al 4 /CuAl 2 is a non-coherent crystal plane and does not have good lattice matching. The average particle size of CuAl 2 is 11.95 µm and that of Al is 28.3 µm. However, the kernel average misorientation (KAM) value at the brazed joint interface is obviously higher than that at the brazed joint interface copper, so the defect density at the brazed joint interface aluminum is higher than that at the brazed joint interface copper. At the same time, due to poor corrosion resistance at the interface on the aluminum side of the brazed joint, serious corrosion spots and corrosion cracks occur at the same time, which leads to the shear performance of the brazed joint decreasing by about 75% after salt spray test for 240 h.

The application of a specific rheological polishing slurry is proposed first for high-efficiency machining of steel materials to achieve high-quality ultraprecision finished surfaces. The rheology of the polishing slurry was explored to show that the non-Newtonian medium with certain parameters of content components exhibits shear-thickening behavior. Then the new high-efficiency nano polishing approach is applied to process spherical surfaces of bearing steel. Several controllable parameters such as shear rheology, abrasive data, rotational speed, and processing time are experimentally investigated in this polishing process. A special finding is that the surface roughness and material removal rate can increase simultaneously when a small abrasive size is applied due to the thickening mechanism during the shearing flow of slurries. Excessive abrasives can decrease surface quality due to the uneven agglomeration of particles scratching the surface. Under optimized conditions, a high-accuracy spherical bearing steel surface with a roughness of 12.6 nm and roundness of 5.3 μm was achieved after a processing time of 2.5 h. Thus, a potential ultraprecision machining method for target materials is obtained in this study.

This study examines the rheological properties of shear thickening fluid (STF) enhanced by additives such as multi-walled carbon nanotubes (MWCNTs), polyvinylpyrrolidone (PVP), and nano-silica (SiO 2 ) at different mass fraction ratios. The rheological properties of the liquid (MWCNTs–PVP/SiO 2 –STF) and the effect of the rheological properties of the STF under different plate spacing of the rheometer were investigated. The optimal mass fraction mixing ratio was also studied. The MWCNTs–PVP/SiO 2 –STF system with different PVP mass fractions was fabricated using ultrasonic technology and the mechanical stirring method. Then, the steady-state rheological test of the MWCNTs–PVP/SiO 2 –STF system was carried out with the aid of the rheometer facility. Dynamic rheological and temperature sensitivity tests on the MWCNTs–PVP/SiO 2 –STF system with 0.1 and 0.15% PVP mass fractions were performed. The rheological test results show that the MWCNTs–PVP/SiO 2 –STF system has a significant shear thickening effect when the PVP mass fraction is increased from 0 to 0.15%. When the PVP mass fraction is 0.1% and the plate spacing is 1 mm, the system exhibits the best shear thickening performance. This is based on the following facts: the viscosity can be achieved as 216.75 Pa s; the maximum energy storage and energy consumption capabilities can be observed. As a result, PVP can significantly enhance the shear thickening performance of the MWCNTs/SiO 2 –STF system.

ZnO nanomaterials with the stereochemical structure were becoming a research focus in the scope of photocatalytic materials, but the ZnO was sensitive to UV light rather than the solar light source, which considerably prohibited its extended application. ZnO nanomaterials coupled with other nanomaterials could generate the alternative composite heterojunction nanomaterials to promote the photocatalytic activity. Herein, we reported two facile and feasible synthesis methods to fabricate TiO 2 /ZnO cube nanocomposites and Ag/ZnO hollow spheres by hydrothermal reaction and chemical deposition, respectively. In this regard, these composited nanomaterials have been successfully fabricated with high purities, good morphology, and crystal structure. Noticeably, in contrast with TiO 2 /ZnO and Ag/ZnO bulk nanocomposites, the Ag/ZnO hollow spheres could offer the higher activity for RhB degradation under the visible light. Moreover, the photocatalytic performance of Ag/ZnO for RhB degradation could be improved synergistically, and the effect of RhB degradation was highest when the Ag mass ratio was modulated at 10% in the sample. Furthermore, it remained a high photocatalytic efficiency even after four cycles. This protocol provided an approvable approach to fabricate efficient photocatalysts with persistent photostability in the wastewater treatment process. Graphical abstract

Repair of critical bone defects is a challenge in the orthopedic clinic. 3D printing is an advanced personalized manufacturing technology that can accurately shape internal structures and external contours. In this study, the composite scaffolds of polylactic acid (PLA) and nano-hydroxyapatite (n-HA) were manufactured by the fused deposition modeling (FDM) technique. Equal mass PLA and n-HA were uniformly mixed to simulate the organic and inorganic phases of natural bone. The suitability of the composite scaffolds was evaluated by material characterization, mechanical property, and in vitro biocompatibility, and the osteogenesis induction in vitro was further tested. Finally, the printed scaffold was implanted into the rabbit femoral defect model to evaluate the osteogenic ability in vivo . The results showed that the composite scaffold had sufficient mechanical strength, appropriate pore size, and biocompatibility. Most importantly, the osteogenic induction performance of the composite scaffold was significantly better than that of the pure PLA scaffold. In conclusion, the PLA/n-HA scaffold is a promising composite biomaterial for bone defect repair and has excellent clinical transformation potential.

Nano calcium silicate hydrate (nano-C–S–H) has become a novel additive for advanced cement-based materials. In this paper, the effect of nano-C–S–H on the early-age performance of cement paste has been studied, and some micro-characterization methods were used to measure the microstructure of nano-C–S–H-modified cement-based material. The results showed that the initial fluidity of cement paste was improved after addition of nano-C–S–H, but the fluidity gradual loss increased with the dosage of nano-C–S–H. The autogenous shrinkage of cement paste can be reduced by up to 42% maximum at an appropriate addition of nano-C–S–H. The mechanical property of cement paste was enhanced noticeably after adding nano-C–S–H, namely, the compressive strengths were improved by 52% and 47.74% at age of 1 day and 7 days, respectively. More hydration products were observed and pore diameter of cement matrix was refined after adding nano-C–S–H, indicating that the early hydration process of cement was accelerated by nano-C–S–H. This was mainly attributed to seed effect of nano-C–S–H. The detailed relationship between microstructure and early-age performance was also discussed.

The interfacial bonding between the fiber and matrix plays a pivotal role in deciding the mechanical performance of fiber-reinforced composites. Basalt fibers, due to the absence of surface functional groups, do not interact potentially with the matrix and hence it leads to insufficient load-carrying capacity of the composite. Incorporating nanomaterials in the matrix and surface treatment of the reinforced fiber can improve the fiber–matrix interface. However, poor dispersion of nanomaterials and the complexity of surface treatment methods restrict their industrial applications. Coating nanomaterials directly onto the fiber surface has the potential to distribute the nanomaterials uniformly, along with strengthening the interfacial bonding between the fiber and matrix. In this study, graphene oxide was coated on the basalt fabric through electrophoretic deposition (EPD), and was further reinforced into the epoxy matrix. The aim of this study is to examine the effects of graphene oxide-coated basalt fiber using EPD on the mechanical and tribological performance of the composite. For comparison, epoxy/basalt composites and graphene oxide-coated epoxy/basalt composites were also prepared. Results showed that due to the improved fiber–matrix bonding and uniform distribution of graphene oxide, the coated basalt-reinforced composites showed better tensile strength and less wear loss.

Nano-silica (NS) is one of the most important nanomaterials in recent years. It is used as a new cement-based composite reinforcement in building materials because of its high volcanic ash activity. In order to achieve the goal of carbon peaking and carbon neutralization, combined with the research idea of cementitious materials-reducing admixture for concrete, under the condition of reducing the amount of cement in concrete by 20%, the influence of different dosages of NS on the setting time and mechanical properties of concrete was analyzed. In addition, the shrinkage performance, impermeability, and resistance to chloride-ion permeability of concrete were also studied. The results show that under the same curing conditions and ages, when the NS dosage is 2.5%, the compressive strength and splitting tensile strength of the specimen after 28 days of curing are the highest, reaching 40.87 and 3.8 MPa, which show an increase by 6.6 and 15.15%. The shrinkage performance of concrete increases with the increase in NS dosage. In addition, when the NS dosage is 2.0%, the durability of concrete has also been greatly improved. The impermeability of concrete increased by 18.7% and the resistance to chloride-ion permeability increased by 14.7%. Through microscopic analysis it was found that NS can promote the hydration reaction, generate more hydration products such as calcium silicate hydrate (C–S–H), enhance the interfacial adhesion between the matrix and the aggregate, and form a closer interfacial transition zone. Moreover, the addition of NS also reduces the cumulative pore volume in concrete, refines the pore size, and makes the internal structure of concrete denser.

In this study, the cellular microstructural features in a subgrain size of carbon nanotube (CNT)-reinforced aluminum matrix nanocomposites produced by laser powder bed fusion (LPBF) (a size range between 0.5–1 μm) were quantitatively extracted and calculated from scanning electron microscopy images by applying a cell segmentation method and various image analysis techniques. Over 80 geometric features for each cellular cell were extracted and statistically analyzed using machine learning techniques to explore the structure–property linkages of carbon nanotube reinforced AlSi10Mg nanocomposites. Predictive models for hardness and relative mass density were established using these subgrain cellular microstructural features. Data dimension reduction using principal component analysis was conducted to reduce the feature number to 3. The results showed that even AlSi10Mg nanocomposite specimens produced using different laser parameters exhibited similar Al–Si eutectic microstructures, displaying a large difference in their mechanical properties including hardness and relative mass density due to cellular structure variance. For hardness prediction, the Extra Tress regression models showed a relative error of 2.47% for prediction accuracies. For the relative mass density prediction, the Decision Tress regression models showed a relative error of 1.42% for prediction accuracies. The results demonstrate that the developed models deliver satisfactory performance for hardness and relative mass density prediction of AlSi10Mg nanocomposites. The framework established in this study can be applied to the LPBF process optimization and mechanical properties manipulation of AlSi10Mg-based alloys and other additive manufacturing newly designed alloys or composites.

This study aimed to prepare and characterise polylactic acid (PLA) reinforced with cellulose nanofibre (CNF) from a Pennisetum purpureum -based composite scaffold and determine its structural and mechanical properties. Porous scaffolds with CNF compositions of 5‒20 wt% in the PLA matrix were developed using solvent casting and particulate leaching of its porogen at 90 wt% of loadings. Morphology studies using field emission scanning electron microscopy revealed that the scaffolds had well-interconnected pores with an average pore size range of 67‒137 µm and porosity >76%. X-ray diffraction confirmed the interconnectivity and homogeneity of the pores and the fibrous structure of the scaffolds. The compressive strength of the fabricated scaffolds varied between 2.34 and 6.66 MPa, while their compressive modulus was between 1.95 and 6.04 MPa for various CNF contents. Furthermore, water absorption and thermal degradation studies showed that the scaffold had good hydrophilicity and improved thermal stability. These findings highlight the need to modify the pore structure and mechanical performance simultaneously for tissue engineering. Thus, this study concludes that the developed PLA scaffolds reinforced with CNF from Pennisetum purpureum are potential candidates for cell attachment and extracellular matrix generation. Graphical abstract

In this study, a hydrothermal technique was used to synthesize lead sulfide (PbS) and silver (Ag)-doped PbS nanoparticles (NPs) at different concentrations of 20, 40, and 60% of Ag. The small lattice phase changes appeared due to the shifting of diffraction angle peaks toward higher 2 θ for samples doped with PbS with increasing Ag content. The analysis of average crystallite size, phase structure, and lattice constant was observed under X-ray diffraction. The value of crystallite size, volume of the unit cell, and porosity (%) were found to increase with the increasing concentration of Ag NPs in PbS. The pure PbS crystallite size is small compared to Ag-doped PbS. The optical characteristics including absorption spectra of the prepared samples were investigated and confirmed by using scanning electron microscope and UV-Vis spectroscopy. The observation of the composition showed that higher doping concentrations of Ag lead to an increase in particle size. Absorption peaks in the UV-Vis spectra corresponding to pure and 20, 40, and 60% of Ag/PbS were observed at different wavelengths of 368, 369, 371, and 372 nm, respectively. Fourier transformation infrared spectroscopy peaks were found in the vibration mode of the ions due to the increment in Ag doping concentrations. These results indicate the possibility of tuning the optical structural properties of Ag-doped PbS through doping various concentrations of Ag NPs. Ag-doped PbS is considered promising future semiconductor nanomaterial, which will enhance the efficiency of photovoltaic device applications. Graphical abstract

The clean production and washing resistance of nano-coating have always been common issues in nano-functional polyester textiles because of the dense structure and chemically inert surface. Here, we developed a clean treatment strategy for preparing washable silver nanoparticle (AgNP)-coated polyester fibers through high-temperature, high-pressure hydrothermal self-assembly of AgNPs in polyester fibers. AgNPs with high affinity to polyester were prepared through the hydrothermal reduction of AgNO 3 by hyperbranched poly(amide-amine)s. The as-prepared spherical AgNPs possessed a uniform particle size (∼7.52 nm), a positive charge (zeta potential of +54.52 mV), and good dispersibility and chemical stability at 110–130°C. The optimal clean treatment conditions had Ag concentrations of 1–50 mg/L, impregnation time of 2 h, and impregnation temperature of 110°C. Therefore, the Ag content of polyester fibers in the range 0–2,500 mg/kg could be precisely controlled. The as-prepared polyester fibers exhibited excellent antibacterial activities and washing resistance and low Ag release (0.00024% for 24 h). Even when the Ag content was as low as ∼50 mg/kg, the corresponding bactericidal rates increased to 99.99% for Escherichia coli and 99.93% for Staphylococcus aureus . The sample containing ∼200 mg/kg of Ag could achieve up to a 99.99% bactericidal rate for E. coli and 99.9% for S. aureus even after 50 standard washes.

The strength and wear resistance of aluminium alloys must be improved to enhance their usage in lightweight constructions. Thus, in this study, graphene nanoplates (GNPs) and boron nitride (BN) nanoparticles were reinforced into the Al 5251 aluminium alloy by friction stir processing (FSP). The Al 5251 aluminum alloy sheets were patterned with holes and filled by mono GNPs, mono BN nanoparticles and a hybrid of BN nanoparticles and GNPs. The microstructure, wear, and mechanical properties of the as-received, after FSP, and the manufactured surface nanocomposites were analysed. Wear tests were performed using two methods: weight loss and volume loss methods. FSP led to four times grain refinement. Due to the Zener pinning effect, the reinforcement nanoparticles improved the grain refinement effect by seven times decrease in the mean grain size. The wear rate by volume and weight loss with reinforcing BN nanoparticles decreased by 160 and 1,340%, respectively. Note that the GNP reinforcement insignificantly improved the wear resistance and hardness compared with the BN nanoparticles. The hardness was increased by 50, 120, and 80% by reinforcing the Al 5251 alloy with GNPs, BN, and a hybrid of BN nanoparticles and GNPs, respectively. The nanocomposite reinforced with GNPs exhibited superior mechanical properties compared to the other nanocomposites.

The electrospray deposition (ESD) method was used to deposit carbon nanotubes (CNTs) onto the surface of glass fiber (GF). The morphology of the hybrid CNTs-GF was analyzed using a field emission scanning electron microscope, and the images indicated that the CNTs were uniformly and homogenously deposited onto the GF’s surface. Laminated composite based on GF and hybrid CNTs-GF were then fabricated via vacuum-assisted resin transfer molding. The mode I interlaminar fracture toughness was measured using the double cantilever beam test method. The hybrid CNTs-GF showed a 34% increase in fracture toughness relative to the control sample. The mechanism of interlaminar fracture toughness enhancement was elucidated via fractography, where fiber bridging, adhesive and cohesive failures, hackles, and coarse matrix surface were observed along the crack pathways. Graphical abstract

The goals of this paper are to study the frost resistance of steel slag concrete (SSC), research the damage mechanisms, and predict the service life of SSC in cold regions. First, the stability of steel slag (SS) was tested, and then SS samples with different treatment dosages were used as aggregates to replace natural aggregates of equal volumes in the preparation of C40 concrete. The microstructures of concrete and micro properties of cement hydration products were investigated in nanospace in this research. In addition, rapid frost resistance durability tests were carried out under laboratory conditions. The results revealed that the ordinary concrete (OC) exhibited a more serious damage phenomenon, and the mass loss and relative dynamic elastic modulus of OC were changed by 5.27 and 62.30%, respectively. However, with increases in the SS content, the losses in mass were lowered. Furthermore, the relative dynamic elastic modulus decreased less, and the frost resistance of the specimens was stronger. The range of mass loss rate was between 2.233 and 3.024%, and the relative dynamic elastic modulus range was between 74.92 and 91.09%. A quadratic function with a good fitting degree was selected to establish a freezing-thawing damage calculation model by taking the relative dynamic elastic modulus as the variable. Then, the freezing-thawing durability lifespan of concrete in the colder regions of northern China was successfully predicted by using the damage calculation model. The results of SSC 20–60 showed the better frost resistance durability when the content of SS sand was 20% and the dosage of SS stone was 60%. Its frost resistance lifespan was more than twice that of OC, which demonstrated that SS as an aggregate could effectively improve the frost resistance lifespan of concrete to a certain extent.

Herein, the synthesis of silver nanoparticles using extracts of pistachio seed coat waste is investigated. The surface plasmon resonance peak at 443 nm was observed in the nanoparticles by using ultraviolet-visible spectroscopy (UV-Vis). To identify potential biomolecules involved in the bio-reduction of silver ions, Fourier-transform infrared spectroscopy (FTIR) was used. Scanning and transmission electron microscopy (SEM and TEM) show irregular shapes with an average size of ∼20 nm. The active surface determined by Brunauer, Emmett, and Teller analysis was 22 m 2 /g. The effect of silver nanoparticles on eggplants sprayed with a nanoparticle suspension of 75 mg/L led to increased plant growth and chlorophyll and carotenoid contents. The fly ash addition to the soil promoted plant growth. The highest increase in plant growth occurs when plants were sprayed with 75 ppm AgNPs in 20% fly ash amended soil.

To clarify the influence of geometric parameters of parallel plate on rheological properties of polyurea elastomer (PUA)-modified asphalt, nano-PUA powder was prepared, and nano-PUA powder modifier was modified by using high-speed shearing apparatus. The apparent viscosity of modified asphalt was evaluated by Brookfield viscosity. The rheological parameters of PUA-modified asphalt were determined by comparing the rheological test results of temperature scanning, frequency scanning, and multiple stress creep recover test using 8 and 25 mm parallel plates. Results indicated that the higher the content of nano-PUA modifier was, the better the high-temperature performance of asphalt would be. When using the 8 mm parallel plate, the high-temperature performance of modified asphalt was worse than that of matrix asphalt, and the PUA modifier would lead to a negative effect on the rheological property of asphalt. Regarding the 25 mm parallel plate, the high-temperature performance of modified asphalt was better than that of matrix asphalt, which was contrary to the results of 8 mm parallel plate. The rheological test results using 25 mm parallel plate were consistent with the results of Brookfield viscosity, indicating that 25 mm parallel plate was more suitable for evaluating the rheological performance of PUA-modified asphalt.

This research addresses the asphalt smoke emission in the process of asphalt pavement construction. The nano-graphene oxide (GO)/tourmaline composites were prepared to alleviate the asphalt smoke emission and improve the construction environment. The macrocharacteristics and micromorphology of the composites were analyzed, and their optimal preparation process was determined. Using material microanalysis methods, such as X-ray diffractometer, Raman spectroscopy, and Fourier transform infrared spectrometer, the structural characteristics and material composition of the composites were studied. The adsorption properties of the composites on asphalt smoke were clarified. It will provide technical support for the improvement of infrastructure construction environment. The results show that 3-aminopropyl triethoxysilane is superior than hexadecyl trimethyl ammonium bromide in surface modification of tourmaline. During the composite process, surface modifiers and GO had no significant effect on the structure of tourmaline. GO could enhance the adsorption properties of tourmaline on asphalt smoke. When the GO content was 1.5 wt%, the improvement was the largest, which is 17.42%. At that time, the emission-reduction rate of asphalt smoke reached 41.11%.

Graphene oxide (GO) is a versatile material with inherent unique properties that can be used in a wide range of applications. GO is produced from graphitic materials including graphite, and its properties can depend on the nature of stacking in the graphene structures. In this study, GO was prepared from pitch-based graphite fibers via the modified Hummer’s method and subsequently incorporated into an epoxy matrix to obtain graphene-loaded nanocomposites (EP/GO). Presented experimental results revealed that the addition of 0.6 wt% GO yielded an ∼110% increase in the fracture toughness. The corresponding fracture energies as well as the flexural strengths and flexural modulus exhibited similar trends to the fracture toughness. The thermophysical properties of the EP/GO, to further demonstrate the reinforcing effectiveness of GO, were also observed. Collectively, these results indicate that GO investigated in the study can be a viable reinforcement candidate to develop next-generation nanocomposites with multifunctional properties.

To date, the use of nanocarriers has been developed in various fields, especially in cancer treatment. Graphene oxide (GO) is a novel drug delivery system that eagerly attracts the attention of many researchers due to its unique features. For the first time, a biocompatible AS1411 APT-GO-COOH was synthesized for the co-delivery of chemotherapeutics and herbal drugs. Here, a human gastric adenocarcinoma cell line (AGS) was targeted with aptamer-carboxylated graphene oxide (APT-CGO) containing anticancer drugs (curcumin (CUR) and doxorubicin (DOX)). The current study aimed to assess the anti-cancer effect of combination therapy, as well as target genes and proteins interfering in the development of gastric cancer. After attachment of APT to CGO, the drugs (CUR and DOX) were loaded on the carrier, establishing a co-delivery system. Then, physical characteristics, release profile, cytotoxicity assay, cellular uptake, expression rates of the genes (RB1, CDK2, AKT, and NF-KB) and proteins (RB1, CDK2), and the apoptosis rate were determined. The designed co-delivery system for the drugs (CUR and DOX) and APT showed a thermo- and pH-sensitive drug release behavior that successfully reduced the expression of CDK2, AKT, and NF-KB while it enhanced RB1 expression at the gene and protein levels. Also, APT-CGO-drugs were successfully targeted to the AGS cell line, leading to a highly inhibitory property against this cell line compared to CGO-drugs. It seems that the co-delivery of CUR and DOX along with APT as a targeting agent was more effective than CGO-drugs, suggesting a promising candidate for the treatment of gastric cancer. The results showed that this biofunctionalized nanocarrier could reduce the cytotoxicity of the drugs in normal cells and could increase efficiency.

Structural health monitoring (SHM) technology based on the mechanical–electrical sensing effect of various intrinsic smart materials has a good application prospect. Carbon nanotube (CNT) has excellent electromechanical properties and hence can be doped into cement by appropriate dispersive means to produce CNT-modified cement-based smart material (CNTCS) with excellent electromechanical (piezoresistive/piezoelectric) capacity. CNTCS can be developed into a static/dynamic intrinsic sensor for SHM after effective packaging and calibration. Based on the characteristics of CNT, the dispersion methods and the dispersity characterization techniques of CNT in the water/cement matrix are summarized, and then the influence laws of various factors on piezoresistive and piezoelectric sensing behaviors of the corresponding CNTCS are also discussed. The full-frequency domain sensing mechanism of CNTCS is analyzed by combining its finite element model and electromechanical coupling theory, and the practicability of applying CNTCS as an SHM static/dynamic intrinsic sensor is further investigated. Graphical abstract

Cancer treatment is challenging due to late-stage diagnosis, drug resistance and systemic toxicity of chemotherapeutic agents. The formulation of the drug into nanoparticles (NPs) can enhance the treatment efficacy and effectiveness. Therefore, a new cationic niosomal formulation, which contains Tween 80, Tween 60, cholesterol and lysine amino acid as a platform model to enhance transfection efficacy and reach more acceptable stability, and curcumin (Cur) as a biological anti-cancer drug, are introduced. Here, the authors focused on the design and synthesis of novel lysine-mediated niosomal NPs for the effectual and controlled release of the antitumor agent, Cur, and turned to optimize niosome formulations, concerning the volume of cholesterol and surfactant to implement these anticancer agents, simultaneously. The characterization of NPs s was carried out and the results showed the successful synthesis of Cur-entrapped niosomal NPs with high efficacy, sufficient positive charges and a favorable size (95/33 nm). The in vitro studies have been performed to investigate the cytotoxicity, cellular uptake and apoptosis of normal and cancer cells treated by black niosome, free Cur and niosom-loaded Cur. The results showed that implementing agents by niosome caused enhanced cytotoxicity, uptake and anticancer activity in cancer cells in comparison with normal cells. Furthermore, the effect of this nanodrug was surveyed on the 4T1 xenografted Balb/C mouse tumor model. Cur delivery to cancer models caused a higher tumor inhibition rate than in other groups.

This article reports a simple, cost-effective, and eco-friendly biosynthesis of ZnO/Fe 3 O 4 nanocomposites using Callistemon viminalis leaves’ water extract. For the first time, we used a green synthetic route via C. viminalis leaves’ extract to prepare ZnO/Fe 3 O 4 nanocomposites (NCs) using zinc acetate and ferric chloride as precursor materials. Fourier transform infrared (FTIR) spectroscopic results revealed polyphenolic compounds mainly phenolic acids present in the plant extract acted as both reducing and stabilizing agents to synthesize ZnO/Fe 3 O 4 NCs. Outcomes of XRD and X-ray photoelectron spectroscopy confirmed the formation of ZnO–Fe 3 O 4 heterojunction in ZnO/Fe 3 O 4 NCs, with crystallite sizes of 45, 35, and 60 nm, respectively, according to Debye–Scherrer’s formula. EDX confirmed Zn, Fe, and O in the ZnO/Fe 3 O 4 nanocomposite. Scanning electron microscopy and transmission electron microscopy (TEM) analyses revealed the existence of both ZnO and Fe 3 O 4 in the NCs with some agglomeration. The thermal stability of NCs was evaluated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA) in a nitrogen atmosphere. In addition, as-prepared ZnO/Fe 3 O 4 NCs along with biosynthesized ZnO and Fe 3 O 4 (prepared by C. viminalis extract) nanoparticles were examined for photodegradation of methylene blue under visible light irradiation for 150 min. The result reveals that the photodegradation efficiency of ZnO/Fe 3 O 4 NCs (99.09%) was higher compared to that of monometallic ZnO (84.7%) and Fe 3 O 4 (37.1%) nanoparticles.

To monitor the progress and prevent the spread of the COVID-19 pandemic in real time and outside laboratories, it is essential to develop effective tests that can ensure rapid, selective, and reliable diagnosis of infected persons in different environments. Key in this regard is the lateral flow immunoassays (LFIAs) that can detect the presence of the SARS-CoV-2 virus quickly, with the aid of nanoparticles (NPs) and specific proteins. We report the use of gold (Au) NPs AuNPs synthesised from a gold( iii ) chloride tetrahydrate precursor in a USP device and collected in a suspension composed of deionised water with polyvinylpyrrolidone as a stabiliser and cryoprotectant. In combination with freeze-drying of the AuNPs’ suspension to achieve water elimination, improved stability, and the target concentration, they exhibit the necessary properties for use as markers in LFIA rapid diagnostic tests. This was confirmed by complementary characterisation determined by using the techniques including inductively coupled plasma-optical emission spectrometry, dynamic light scattering method and zeta-potential, ultraviolet-visible spectroscopy, X-ray diffraction, scanning electron microscopy with energy dispersion spectrometer, and transmission electron microscopy, as well as with the preparation of a prototype LFIA test strip with AuNPs. Thus, such AuNPs, as well as the USP method, show promise for the development of new markers for use in LFIA. Graphical abstract

For the high demand for cement-based materials in buildings, improving the performance of cement-based materials has become the focus of relevant researchers. In recent years, nanomaterials have broad prospects in many fields such as architecture by virtue of their “lightweight, high strength, and strong solidity” characteristics. As a modifier of cement-based materials, it has also become a research hotspot. Graphene oxide (GO) is one of the most representative graphene-based nanomaterials. Because of its extremely high specific surface area and excellent physical properties, it has greatly improved the properties of cement-based materials. GO acts as an enhancer of cement composites that brings people unlimited imagination. The research progress of GO-modified cement-based materials is reviewed. The purpose is to point out the limitations of current research and provide a reference for later research. The dispersion treatment of GO and the properties of its modified cement-based materials are analyzed and summarized. In addition, the further research work that is needed and future development prospect are discussed.

This review is intended to provide an overview of the design and fabrication of ionic liquid-based ionic electroactive polymer (IL-iEAP) transducers for advanced applications in biological and electronic fields. The iEAP is a class of smart materials that can perform sensing or actuating functions by controlling the movement of cations and anions in the active layer. This type of material can deform under low voltage stimulation and generate electrical signals when undergoing mechanical deformation because of ion redistribution. Numerous research attention has been focused on studying the deformation mechanisms and the potential for actuation, sensing, and energy harvesting applications. Compared to the traditional water-based iEAP, the non-volatile IL-iEAP delivers a wider electrochemical window and a more stable actuation performance. In this paper, the classification of iEAP with different actuation mechanisms is first outlined, followed by introducing various preparation methods including nanotechnology for IL-iEAPs, and discussing the key factors governing their actuation performance. In addition, the advanced functions of IL-iEAP in actuating and sensing, especially self-sensing in bionics and electromechanical equipment applications, are reviewed. Finally, novel nanotechnologies used for fabricating IL-iEAPs and the prospects of their microelectromechanical system (MEMS) applications are discussed.

Electrocatalysts play a significant performance in renewable energy conversion, supporting several sustainable methods for future technologies. Because of the successful fabrication of distinctive oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) electrocatalysts, bifunctional ORR/OER and HER/OER electrocatalysts have become a hot area of contemporary research. ORR, OER, and HER have gained considerable attention because of their strong performance in different energy conversion and storage devices, including water-splitting devices, fuel cells, and metal–air rechargeable batteries. Therefore, the development of effective nanostructured multifunctional electrocatalysts for ORR, OER, and HER is necessary; and there is a demand for their industrialization for sustainable energy technology. In this review, details of current improvements in multifunctional catalysts for ORR/OER as well as HER/OER are presented, focusing on insight into the theoretical considerations of these reactions through investigation and estimation of different multifunctional catalysts. By analyzing the universal principles for various electrochemical reactions, we report a systematic scheme to clarify the recent trends in catalyzing these reactions over various types of nanostructure catalysts. The relevant reaction pathways and the related activity details for these reactions in the current literature are also included. Overall, the current demands and future outlines for improving the prospects of multifunctional electrocatalysts are discussed.

Yarn-based strain sensor is an emerging candidate for the fabrication of wearable electronic devices. The intrinsic properties of yarn, such as excellent lightweight, flexibility, stitchability, and especially its highly stretchable performance, stand out the yarn-based strain sensor from conventional rigid sensors in detection of human body motions. Recent advances in conductive materials and fabrication methods of yarn-based strain sensors are well reviewed and discussed in this work. Coating techniques including dip-coating, layer by layer assemble, and chemical deposition for deposition of conductive layer on elastic filament were first introduced, and fabrication technology to incorporate conductive components into elastic matrix via melt extrusion or wet spinning was reviewed afterwards. Especially, the recent advances of core–sheath/wrapping yarn strain sensor as-fabricated by traditional spinning technique were well summarized. Finally, promising perspectives and challenges together with key points in the development of yarn strain sensors were presented for future endeavor.

Advanced materials were used and are being implemented in structural, mechanical, and high-end applications. Contemporary materials are used and being implemented in structural, mechanical, and high-end applications. Composites have several major capabilities, some of them being able to resist fatigue, corrosion-resistance, and production of lightweight components with almost no compromise to the reliability, etc. Nanocomposites are a branch of materials within composites, known for their greater mechanical properties than regular composite materials. The use of nanocomposites in the aerospace industry currently faces a research gap, mainly identifying the future scope for application. Most successes in the aerospace industry are because of the use of suitable nanocomposites. This review article highlights the various nanocomposite materials and their properties, manufacturing methods, and their application, with key emphasis on exploiting their advanced and immense mechanical properties in the aerospace industry. Aerospace structures have used around 120,000 materials; herein, nanocomposites such as MgB 2 , multi-walled carbon nanotubes, and acrylonitrile butadiene styrene/montmorillonite nanocomposites are discussed, and these highlight properties such as mechanical strength, durability, flame retardancy, chemical resistance, and thermal stability in the aerospace application for lightweight spacecraft structures, coatings against the harsh climate of the space environment, and development of microelectronic subsystems.

The rapid economic growth and environmental concerns have led to high demands on paper and paper-based products in terms of variety, quantity, quality, and specialty. Enhancement and functionalization with additives are constantly required. Moving away from traditional petroleum-based additives, researchers have attempted to use “green” nanoadditives by introducing renewable environmentally friendly nanocellulose. This article studies the functions of nanocellulose as bio-additives (enhancer, retention and filtration reagent, and coating aid) in paper and paper products, and overviews the research development of nanocellulose-based additives and their applications in the paper industry for both efficient production and paper functionalization. The review shows that (1) a variety of nanocellulose-based bioadditives have been reported for various applications in paper and paper-based products, while commercially viable developments are to be advanced; (2) nanocellulose was mostly formulated with other polymer and particles as additives to achieve their synergistic effects; (3) major interests have concentrated on the nanocellulose in the specialty papers as representing more value added products and in the efficient utilization of recycled fibers, which remains most attractive and promising for future development. This report shall provide most useful database information for researchers and industries for paper recycling and enhancement, and paper-based products innovation and application.

Graphene is a single-atom-thick sheet of sp 2 hybridized carbon atoms that are packed in a hexagonal honeycomb crystalline structure. This promising structure has endowed graphene with advantages in electrical, thermal, and mechanical properties such as room-temperature quantum Hall effect, long-range ballistic transport with around 10 times higher electron mobility than in Si and thermal conductivity in the order of 5,000 W/mK, and high electron mobility at room temperature (250,000 cm 2 /V s). Another promising characteristic of graphene is large surface area (2,630 m 2 /g) which has emerged so far with its utilization as novel electronic devices especially for ultrasensitive chemical sensor and reinforcement for the structural component applications. The application of graphene is challenged by concerns of synthesis techniques, and the modifications involved to improve the usability of graphene have attracted extensive attention. Therefore, in this review, the research progress conducted in the previous decades with graphene and its derivatives for chemical detection and the novelty in performance enhancement of the chemical sensor towards the specific gases and their mechanism have been reviewed. The challenges faced by the current graphene-based sensors along with some of the probable solutions and their future improvements are also being included. Graphical abstract

Peripheral nerve injuries resulting from various traumatic events can cause mobility problems and sensory impairment, jeopardizing patients’ life quality and bringing serious economic burdens. Due to the shortcomings of autologous nerve grafts, such as limited tissue sources, unmatched size, and loss of innervation at the donor site, tissue-engineered nerve grafts using both natural and synthetic materials have been employed in the treatment of peripheral nerve defect and to promote nerve regeneration. Apart from traditional advantages such as good biocompatibility and controllable degradation, the development of fabrication technology and the advancement in material science have endowed tissue-engineered nerve conduits with upgraded properties such as biomimetic surface topography, extracellular matrix components, neurotrophic factors, and cell seeding, or a conduit with micropores on the surface for substance exchange and/or with fillers inside for microenvironment simulation. This article reviews recent progress in the biomaterials employed in fabricating tissue-engineered nerve conduits, in vitro characterization, and their applications in nerve repair in animal studies as well as in clinical trials.

Research and development on superhydrophobic carbon nanostructures and their nanocomposites have high industrial significance. Here, a comprehensive review of the topic is provided. Reported works on superhydrophobic surfaces and coatings of carbon nanotubes, nanofibres, nanospheres/nanothorns/others, nanodiamond, fullerene and their various nanocomposites with metals, ceramics, and polymers are described. Superhydrophobic nanostructured carbon soot, graphitic carbon, and others are also presented. The section on superhydrophobic graphene is presented concisely at the end. Reports in different application areas, including anti-corrosion, anti-icing, oil separation, anti-biofouling, and sensors, are discussed separately. Superoleophobic and superamphiphobic surfaces are also discussed. Graphical abstract

The recent increase in the use of graphene and its derivatives is due to their exceptional physicochemical, electrical, mechanical, and thermal properties as the industrial materials developed by involving graphene structures can fulfill future needs. In that view, the potential use of these graphene-containing nanomaterials in electronics applications has encouraged in-depth exploration of the electronic, conducting, and other functional properties. The protecting undifferentiated form of graphene has similarly been proposed for various applications, for example, as supercapacitors, photovoltaic and transparent conductors, touch screen points, optical limiters, optical frequency converters, and terahertz devices. The hybrid composite nanomaterials that undergo stimulus-induced optical and electrical changes are important for many new technologies based on switchable devices. As a two-dimensional smart electronic material, graphene has received widespread attention, and with that view, we aim to cover the various types of graphene oxide (GO)-based composites, linking their optical and electrical properties with their structural and morphological ones. We believe that the topics covered in this review can shed light on the development of high-yield GO-containing electronic materials, which can be fabricated as the field moves forward and makes more significant advances in smart optoelectronic devices.

The rapid construction of innovative structures and megastructures is pushing the development of steel fiber reinforced cementitious composite (SFRCC). The interfacial enhancement technology from nano to macroscale for improving global properties of SFRCC is summarized here, including nanomaterials reinforcement of cementitious matrix, physical arrangement and nanomaterials modification of steel fiber. The interfacial bonding strength of SFRCC can be enhanced more than 150% via these approaches. To evaluate the effect of local interfacial technology on global mechanical properties of SFRCC, the structural performance of SFRCC with interfacial modification is reviewed. The energy absorption capacity of SFRCC can be improved over 20% through interfacial enhancement technology. The multi-scale mechanisms behind these approaches are illustrated through macroscale characterizations and molecular dynamics modeling. Furthermore, the key challenges and future prospects of enhancement approaches are also discussed from the perspectives of bottom-up system, nanoscale reinforcement, and durability properties in SFRCC, which are expected to inspire further improvement in interfacial performance and promote the application of SFRCC in practical engineering. Graphical abstract

Metal nanoparticles have been widely used in the treatment of diabetic wounds owing to their proven antibacterial activity and enhanced wound healing effects. Therefore, in this review, we discuss the use of metal nanoparticles in managing diabetic wounds, mainly silver nanoparticles (AgNPs), gold nanoparticles (AuNPs), and zinc nanoparticles (ZnO nanoparticles), as well as their combination with biomaterials such as chitosan, bacterial cellulose, growth factors, etc . The combination of metal nanoparticles and biomaterials reportedly halts the growth and multiplication of bacterial strains commonly involved in diabetic wounds, including gram-positive ( Staphylococcus aureus and Acinetobacter calcoaceticus ) and gram-negative bacteria ( Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae ). Furthermore, these combinations have demonstrated enhanced wound healing of diabetic wounds during in vitro and in vivo studies. Additionally, we highlighted the barriers and challenges associated with the use of metal nanoparticles, including toxicities. Moreover, toxicities were mainly related to the method of synthesis employed, as well as the physical characteristics of nanoparticles, including size, shape, surface charge, and morphology. Collectively, dual-therapy composed of metal nanoparticles and biomaterials has been shown to promote wound healing and can be developed as a promising future therapy for better outcomes in diabetic wound healing.

Bio-organic, as one of the sustainable and bioresorbable materials, has been used as an active thin film in producing resistive switching random access memory (RRAM) due to its specialized properties. This type of nonvolatile memory consists of a simple unit structure with the processed and solidified bio-organic-based thin film sandwiched between two electrodes. Its memory characteristics are significantly affected by the resistive-switching mechanism. However, to date, the reported mechanisms are very diverse and scattered, and to our best knowledge, there is no literature that reviewed comprehensively the mechanisms of resistive switching in bio-organic-based thin films. Therefore, the objective of this article is to critically analyze data related to the mechanisms of the bio-organic-based RRAM since it was first reported. Based on the pool of literature, three types of mechanisms are categorized, namely electronic, electrochemical, and thermochemical, and the naming is well justified based on the principle of operation. The determining factors and roles of bio-organic material and the two electrodes in governing the three mechanisms have been analyzed, reviewed, discussed, and compared.

Applications of nanotechnology in biomedical engineering are vast and span several interdisciplinary areas of nanomedicine, diagnostics, and nanotheranostics. Herein, we provide a brief perspective on nanotechnology as an enabling tool for the design of new functional materials and devices for medical applications. Semiconductor nanocrystals, also known as quantum dots, are commonly used in optical imaging to diagnose diseases such as cancer. Varieties of metal and metal oxide nanoparticles, and two-dimensional carbon-based nanostructures, are prospective therapeutics and may also be used in protective antiviral/antibacterial applications. Similarly, a number of nanomaterials have shown the potential to overcome the drawbacks of conventional antiviral drugs. However, assessing the adverse effects and toxicities of nanoparticles in medicine and therapeutics is becoming more critical. This article discusses the latest developments of nanomaterials in diagnosis, nanotheranostics, and nanomedicines, with particular emphasis on the importance of nanomaterials in fighting against coronavirus disease. Further, we considered the safety and toxicity of nanomaterials in the context of biomedical applications. Finally, we provided our perspective on the future of nanotechnology in emerging biomedical engineering fields. Graphical abstract

The raw materials of geopolymer come from industrial wastes, which have the advantages of lower carbon emissions and less energy consumption compared with traditional cement products. However, it still has the disadvantages of low strength, easy cracking, and low production efficiency, which limit its engineering application and development. At present, with the application and development of nanotechnology in the field of materials, it is found that nanomaterials have a good filling effect on composites, which greatly improves the integrity of the composites. It has become a very popular research direction to optimize and improve the engineering application performance of geopolymer concrete (GPC) by nanomaterials. The modification of nanomaterials can further improve the properties of GPC and expand its application fields in engineering and life. Based on people’s strong interest in nanomaterial-modified GPC and providing the latest and complete research status for further related work, this paper summarized the key technical problems in the field of nanomaterials-modified GPC in the past decade. Those include the modification mechanism, dispersion mode, and mechanical properties of nanomaterials. At the same time, the application bottlenecks and key problems of nanomaterials-modified GPC are comprehensively analyzed. Finally, the prospects and challenges of future work in this field are discussed.

Nanomedicine is ongoing current research in the applications of nanotechnology for cancer therapy. Simply from a technology perspective, this field of research has an enormous broadening and success to date. Recently, nanomedicine has also made inroads in the treatment of cancer. Stimuli-responsive nanoparticles are an emerging field of research because its targeting capacity is of great interest in the treatment of cancer. The responsive nanoparticles are efficient in encountering different internal biological stimuli (acidic, pH, redox, and enzyme) and external stimuli (temperature, ultrasounds, magnetic field, and light), which are used as smart nanocarriers for delivery of the chemotherapeutic and imaging agents for cancer therapy. In-depth, the responsive nanocarrier that responds to the biological cues is of pronounced interest due to its capability to provide a controlled release profile at the tumor-specific site. The outlook of this review focuses on the stimuli-responsive nanocarrier drug delivery systems in sequence to address the biological challenges that need to be evaluated to overcome conventional cancer therapy.

Silver nanoparticles (AgNPs) have been extensively used in various industries; however, this is accompanied by several implications to humans and the environment. This review focuses on different aspects of AgNPs including the production and detection techniques, their fate, and dynamics in response to different environmental factors. In addition, this review illustrates the toxicity mechanism and the interaction of AgNPs with different matrices, such as aquatic environment, soil, crops, and humans. Reduction measures and future research are discussed. Graphical abstract Practically, AgNPs are converted to the positively charged Ag + ions by dissolution process and will react with the negatively charged oxygen and nitrogen atoms in the vital organelles like DNA, mitochondrion, and the thiol group presented in protein structures and enzymes, which in terms interrupts the normal cell reproduction, and finally, the death of cell will occur according to the toxicity limit of (Ag + ) silver ions level of each organ.

As a green material, wood is widely used in building decoration, railway construction, and other fields. However, the wood itself has inherent defects of being easy to absorb water and deform, rot, and decrease in strength. The physical and mechanical strengths and stability of artificial fast-growing forest wood are even worse. As wood modification can improve the dimensional stability, durability, strength, and other properties of wood, it has been widely used. Chemical modification is the main method of wood modification. The development of nanotechnology has brought more possibilities for wood modification. Owing to the extensive literature available, this article summarizes the representative achievements of wood chemical modification and nanotechnology. The principle, production process, advantages, and disadvantages of various wood chemical modification methods were analyzed, compared, and evaluated. Finally, according to the application status of wood-modified materials, the problems existing in the current wood chemical modification methods and the application of nanotechnology, and the development trend in the future are analyzed.

E-jet printing is a micro- and nano-manufacturing technique that utilizes electric field-induced fluid jet printing for achieving better control and resolution than traditional jet printing processes. In addition to high printing resolution, E-jet printing has advantages in some aspects such as wide material applicability, which has been successfully applied in numerous applications that include sensors, transistors, tissue engineering scaffolds, and photonic devices. This article reviews the electrohydrodynamic jet (E-jet) printing technology, which mainly relies on the principle of electrohydrodynamic-induced fluid movement. At the same time, the process of jet formation and droplet deposition is described. The parameters, nozzle design, and ink characteristics of the jet printing process are summarized. Then, a number of concrete applications based on E-jet printing processes are described in this article. Finally, the future development of this technology has been prospected. Graphical abstract

Research of antiviral textiles has received considerable attention owing to the continuous emergence of new infectious diseases. Antiviral textiles can effectively inhibit the spread of viruses and significantly reduce the risk of cross-infection and re-infection to protect people’s health and safety. In recent years, researchers studied various antiviral materials, which can prevent the spread and reproduction of viruses by killing and reducing their attachment. These materials can be applied to antiviral textiles through finishing and various spinning methods. This review organizes antiviral materials, analyzes their antiviral mechanisms and inhibition effects, and discusses the methods of combining antiviral materials with textiles, as well as their applications in healthcare and public transportation. In addition, prospects for antiviral textile research are proposed. This review provides references for the study of antiviral textiles and may stimulate the continuous research and development of antiviral textiles. Graphical abstract

High-entropy alloys (HEAs) have become a research focus because of their easy access to nanostructures and the characteristics of high strength, hardness, wear resistance, and oxidation resistance, and have been applied in aerospace lightweight materials, ultrahigh temperature materials, high-performance materials, and biomimetic materials. At present, the study of HEAs mainly focuses on the microstructure and mechanical properties. HEAs of Mo, Ti, V, Nb, Hf, Ta, Cr, and W series have high strength, while HEAs of Fe, Co, Ni, Cr, Cu, and Mn series have good toughness. However, the emergence of medium-entropy alloys, metastable HEAs, dual-phase HEAs, and multiphase HEAs increased the complexity of the HEA system, and the phase transition mechanism and strengthening and toughening mechanisms were not fully established. In this article, the preparation, phase formation, phase transformation as well as strengthening and toughening mechanisms of the HEAs are reviewed. The inductive effects of alloying elements, temperature, magnetism, and pressure on the phase transformation were systematically analyzed. The strengthening mechanisms of HEAs are discussed, which provides a reference for the design and performance optimization of HEAs. Graphical abstract

Poor crack resistance, high brittleness, and poor toughness are inherent limitations of traditional cement-based materials. Besides, cement-based materials have certain shortcomings in energy consumption and environmental protection. Therefore, improving the performance of cement-based materials becomes a hot topic in related research. At the same time, the development of nanomaterials and technologies provides researchers with a new research idea: to enhance the performance of cement-based materials at the nanoscale level. Graphene oxide (GO) is one of the most representative nano-reinforcements. Due to its high surface area and excellent physical properties, GO has a surprising effect on improving the performance of cement-based materials. In addition, nanosilica (NS) and carbon nanotubes (CNTs) have excellent improvement on cement-based materials, and people also hope to further improve the performance of cement-based materials through the interaction of various nanomaterials. In this paper, the influence of GO on cement-based materials is reviewed by consulting a lot of correlative literature, mainly focusing on the following aspects: (i) The dispersion of GO in cement paste. (ii) The influence of GO on the properties of cement-based materials, including working performance, mechanical strength, microstructural characteristics, and durability. (iii) The effect of nanohybrid materials of GO, NS, and CNTs on cement-based materials, and the synergistic effects of various nanomaterials are reviewed for the first time. (iv) Evaluation of current progress. This paper aims to provide guidance for the study and application of GO-modified cement-based materials and nanohybrid materials.

Fungal infections are still a major challenge for clinics, resulting from the resistance of drug-resistant fungi and the toxicity of antifungal drugs. Defense against fungal invasions via enzymatic catalysis has been found in nature. The use of nanozymes, as artificial enzyme mimics, may be a promising strategy to induce fungal death due to their advantages such as tunable catalytic activity, high stability, low cost, and easy preparation. Here, the importance of natural enzymes in the defense against fungi is outlined. The progress in antifungal performance and potential application of nanozymes and the related antifungal mechanisms are also summarized. Finally, the perspective and challenges in this field for future study, pointing out that nanozyme-based catalytic therapy represents a promising alternative strategy for antifungal treatment, are highlighted.

Three-dimensional (3D) network topological structure composite (3D-NTSC) is a new type of composite in which both the matrix phase and the reinforced phase have 3D continuous network structure and interweave with each other. Different from fiber reinforcement and particle reinforcement, the reinforcing phase in the composite material runs through the whole matrix phase in a continuous form without destroying the topological continuity of the matrix phase, so that each matrix phase in the composite material can not only maintain its own excellent performance, but also can cooperate with each other and complement each other, so that the composite material can play a greater performance advantage. In recent years, 3D-NTSC has attracted the attention of researchers and has been widely used in practical production. At present, there are no comprehensive articles summarizing the research progress of this kind of materials. In this review, we discussed the recent progress of the preparation methods, including natural flow method, vacuum infiltration process, pressure filling method, in situ filling method, and co-building method. Furthermore, research progress on mechanical properties and some regular results, shortcomings, challenges, and prospects of 3D-NTSC were also put forward, which would be helpful to people working in the related fields.

Fiber-reinforced polymer composites are high-performance materials used extensively in aerospace and defense industries. Researchers have added various nanoscale materials to FRPs for improving their mechanical properties and to prepare multifunctional composites. Carbon nanotubes (CNTs) with their high strength, high modulus, and large aspect ratio have emerged as a frontrunner in the nano-reinforcements, and there is a large volume of published research on this topic. This article provides an extensive review of key publications covering topics of fabrication methods, enhancement of mechanical properties, and applications of CNT-modified FRP materials in structural health monitoring. A description of the main methods of adding CNTs into FRP materials, including dispersion in the resin and film lay-up, is presented. A key focus of the review is the effect of CNTs on the mechanical properties of FRP composites, including interlaminar fracture toughness, impact resistance, and fatigue properties. Since CNTs have self-sensing properties, there is potential to use CNTs for nondestructive identification (NDI) and structural health monitoring (SHM) of composite structures. Finally, a discussion of the problems that might be encountered during the use of CNTs as nano-reinforcements in FRP, and the future application potential of CNT-modified FRP materials is reported.

This review focuses on nano-structured delivery devices prepared from biodegradable and biocompatible natural and synthetic polymers, organic raw materials, metals, metal oxides, and their other compounds that culminated in the preparation of various nano-entities depending on the preparative techniques, and starting raw materials’ utilizations. Many nanoparticles (NPs) made of polymeric, metallic, magnetic, and non-magnetic origins, liposomes, hydrogels, dendrimers, and other carbon-based nano-entities have been produced. Developments in nanomaterial substrate and end products’ design, structural specifications, preparative strategies, chemo-biological interfacing to involve the biosystems interactions, surface functionalization, and on-site biomolecular and physiology-mediated target-specific delivery concepts, examples, and applications are outlined. The inherent toxicity, and safety of the design concepts in nanomaterial preparation, and their applications in biomedical fields, especially to the organs, cellular and sub-cellular deliveries are deliberated. Bioapplications, the therapeutic delivery modules’ pharmacokinetics and medicinal values, nanopharmaceutical designs, and their contributions as nano-entities in the healthcare biotechnology of drug delivery domains have also been discussed. The importance of site-specific triggers in nano-scale deliveries, the inherent and induced structural specifications of numerous nanomaterial entities belonging to NPs, nano-scale composites, nano-conjugates, and other nano-devices of organic and inorganic origins, near biological systems are detailed. Modifications that provide nano-deliveries of their intrinsic therapeutic actions, through structural and physicochemical characteristics modifications, and the proven success of various nano-delivery devices and currently available commercial nanomedicinal and nanopharmaceutical products are also provided.

Cu–Al-based alloys are a kind of new functional material. Due to their unique thermoelastic martensite structure, they have excellent damping performance, which has become a research hotspot in the field of materials science and engineering in recent years. However, the elastic anisotropy and large grain size easily cause a brittle fracture, which is harmful to the mechanical properties of the material. In order to meet the practical needs of engineering, it is an important choice to design Cu–Al-based alloys with excellent mechanical properties and damping performances from the perspective of refining the grain size. When the grain size is small, the effect of fine grain strengthening and interfacial damping can play a role simultaneously to obtain Cu–Al-based alloys with excellent comprehensive properties. In this paper, several common preparation methods of Cu–Al-based alloy are introduced firstly. Then the contributions of researchers in refining grain size from alloying and heat treatment are summarized. Meanwhile, nanomaterials can be used as the reinforcing phase of Cu–Al based alloy, and play a superb role in mechanical properties and damping performances. The purpose of this study is to provide a reference for the further research of structure-function integrated materials with high strength and high damping simultaneously. Finally, the development of Cu–Al-based alloy from the aspects of 3D printing and numerical simulation is prospected. Graphical abstract

Vertically aligned carbon nanotube (VACNT) materials is a promising candidate in different fields. The intrinsic performance of VACNTs, such as a large specific surface area, high conductivity, and especially its vertical conductive channel, stands out the VACNT-based device from conventional carbon material-based devices in the energy, environmental sustainability, and so on. In this review, a comprehensive and in-depth summary on the synthesis method and fundamental mechanisms, and design strategies for the novel VACNT materials, is presented. In addition, an overview of the latest development in high-efficiency utilization of VACNT materials in representative fields, including energy storage and conversion, catalysis, terahertz spectroscopy, biology and biomedicine, and environmental sustainability, is given. Finally, the challenges and promising perspectives of VACNT materials in future development are outlined.

Thermal conductivity and dynamic viscosity are two critical properties of nanofluids that indicate their heat transfer performance and flow. Nanofluids are prepared by dispersing mono or several organic or synthetic nanoparticles in selected base fluids to form mono or hybrid nanofluids. The qualitative and quantitative stability measurement of nanofluids will then be addressed, followed by a detailed discussion on how the dispersion of nanoparticles in water (W), ethylene glycol (EG), and the mixture of W:EG 60:40% by volume affects the thermal conductivity and dynamic viscosity ratio. The data comparison demonstrated that the thermal conductivity ratio increases with increasing normalized concentrations, the bulk temperature of nanofluids, and the smaller nanoparticle size. The dynamic viscosity ratio is multiplied by the normalized concentration increase. Nevertheless, as the bulk temperature climbed from 0 to 80°C, the dynamic viscosity ratio was scattered, and the dynamic viscosity ratio trend dropped with increasing particle size. While the majority of nanofluids enhanced thermal conductivity ratio by 20%, adding carbon-based nanoparticles to synthetic nanofluid increased it by less than 10%. The disadvantage of nanofluids is that they multiply the dynamic viscosity ratio of all nanofluids, which increase power consumption and reduces the efficiency of any mechanical system.

Global overpopulation, industrial expansion, and urbanization have generated massive amounts of wastes. This is considered as a significant worldwide challenge that requires an urgent solution. Additionally, remarkable advances in the field of biomedicine have impacted the entire spectrum of healthcare and medicine. This has paved the way for further refining of the outcomes of biomedical strategies toward early detection and treatment of different diseases. Various nanomaterials (NMs) have been dedicated to different biomedical applications including drug delivery, vaccinations, imaging modalities, and biosensors. However, toxicity is still the main factor restricting their use. NMs recycled from different types of wastes present a pioneering approach to not only avoid hazardous effects on the environment, but to also implement circular economy practices, which are crucial to attain sustainable growth. Moreover, recycled NMs have been utilized as a safe, yet revolutionary alternative with outstanding potential for many biomedical applications. This review focuses on waste recycled NMs, their synthesis, properties, and their potential for multiple biomedical applications with special emphasis on their role in the early detection and control of multiple diseases. Their pivotal therapeutic actions as antimicrobial, anticancer, antioxidant nanodrugs, and vaccines will also be outlined. The ongoing advancements in the design of recycled NMs are expanding their diagnostic and therapeutic roles for diverse biomedical applications in the era of precision medicine. Graphical abstract

Additively manufactured polymeric composites exhibit customised properties beyond those offered by conventionally fabricated ones. However, in many cases, the mechanical performance mainly depends on the processing parameters, tools, and material selection. Yet, one of the issues of the additive manufacturing process especially in the material extrusion process is the inability to control the printing layups, thereby causing interlaminar damage. Thus far, literature and research have focused on improving the mechanical performance of such polymeric composites by focusing on the interlaminar shear strength under a transverse load transfer. Polymeric composites prepared using the material extrusion technique namely fused deposition modelling (FDM) are discussed upon its layup sequence and orientation. This article proposes that by realising a homogenous distribution of the transverse load, the orientation and the printing direction can maximise the printed load bearing. Moreover, the layup sequence and the interlayer diffusion are key for controlling the mechanical properties of the polymeric composites. This brief review presents a comprehensive elucidation of the polymeric composites manufactured using FDM that interprets the needs of having greater load bearing in each layup printing sequence of the polymeric composites. By able to control the layup sequence, one can control the mechanical performance based on specific functionality. Graphical abstract

Quantum dots (QDs) are nanocrystals of a semiconductor material that exist in a size regime less than 10 nm. QDs have become promising nanoparticles for a wide variety of different applications. However, the major drawback of QDs is their potential toxicity. This review reports on some recent methods for the synthesis of QDs and explores their properties, structures, applications, and toxicity. QDs are extraordinary because their minute size produces a physically confined electron cloud, an effect known as the quantum confinement. Certainly, because of their special properties as they had a great unique optical, electronic, and chemical properties that were not observe in other materials. These unique properties of the QD are an attractive material for a variety of scientific and commercial applications, most of them recently been realized, such as biosensors, bioimaging, photodetectors, displays, solar cells, wastewater treatment, and quantum computers. Finally, but not the end, an interesting potential QD application in future perspectives will expect as light-emitting diode products, biomedical applications, and Li-Fi.

Nano-based systems can be used to transport active medicinal products to specific parts of the body. Most challenges with drug delivery, such as low water solubility and poor bioavailability, can be solved using nanotechnology. In addition, nanoparticles can overcome various physiological obstacles to increase load distribution to desired sites. Nanoparticles can carry a load of medication or therapeutic agent, such as a DNA-related substance, to enhance distribution time and deliver the drug to the target site in either a nonspecific (through enhanced permeability and retention (EPR)) or specific (through binding specific target receptors) manner. Moreover, nanoparticle drug delivery systems have been employed in the clinic since the early 1990s. Since then, the field of nanomedicine has developed with growing technical needs to improve the delivery of various medications. Over these past decades, newer generations of nanoparticles have emerged that are capable of conducting new delivery activities that could enable therapy via innovative therapeutic modalities. This review highlights different types of approved and currently marketed nanoparticles, such as nanocrystals, liposomes, lipid nanoparticles, PEGylated polymeric nanoparticles, protein-based nanoparticles, and metal-based nanoparticles. Furthermore, it explores the use of vaccine-loaded nanoparticles for COVID-19 prophylaxis.

The recent past witnessed rapid strides in the development of lithium-based rechargeable batteries. Here, some key technological developments in intercalation, conversion, and alloy-type anode and cathode materials are reviewed. Beyond the active electrode materials, we also discuss strategies for improving electrolytes and current collectors. An outlook with remarks on easily misleading battery characteristics reported in the literature, impending challenges, and future directions in lithium-based rechargeable batteries is provided. Lastly, the authors also emphasize the need for lab-based research at the pouch cell level with practical energy densities, in addition to discussing scalability and economic viability of different battery materials and their architectures. Graphical abstract