Band 35, Heft 1

The cone–disk system (CDS) involves a cone, which contacts a disk at its tip. This type of flow problem is used in some devices in medical sciences, such as viscosimeters and conical diffusers. The 3-D flow of a bio-nanofluid within the gap of a CDS is examined for the four selected arrangements: (i) rotating cone with stationary disk, (ii) rotating disk with stationary cone, (iii) co-rotation of cone and disk, and (iv) counter-rotation of cone and disk. The well-known Buongiorno’s nanofluid model is applied to illustrate the flow behavior with Stefan blowing. The governing system constitutes the continuity, momentum, energy, conservation of nanoparticle volume fraction (NPVF) equation, and density of the motile microorganism (DMM) equations. The Lie group approach is used to obtain invariant transformations. Numerical simulations are done for various rotational Reynolds numbers and various gap angles to explore the flow, heat, NPVF, and DMM transport features. The radial and tangential skin friction factors, Nusselt, Sherwood, and density numbers are calculated and inspected using tabular and graphical results. The slip and blowing parameters are demonstrated to affect the fluid friction, heat, NPVF, and DMM transfer rates from the disk and cone for the selected models.

The aim of this research is to analyse the combined effect of variable thermal conductivity and nonlinear thermal radiation on magnetohydrodynamic (MHD) hybrid nanofluid flow in convergent-divergent channels. The effects of two nanoparticles (i.e. ZrO 2 {\text{ZrO}}_{\text{2}} and SiO 2 {\text{SiO}}_{\text{2}} ) in base fluid (i.e. H 2 O {\text{H}}_{\text{2}}\text{O} ) are considered in this work. The partial differential equations modelling the problem are reduced to ordinary differential equations following the application of the similarity transformations. The system has been solved analytically with the differential transform method and numerically with the Runge–Kutta–Fehlberg 4th–5th order method with the assistance of the shooting technique. Comprehensive analysis and discussion have been conducted regarding the impact of multiple governing parameters on the dimensionless velocity and temperature distributions. These parameters include variable thermal conductivity, nonlinear thermal radiation, Hartman number, and hybrid nanoparticle volume fraction. Finally, this method will provide some insights into the usefulness of MHD hybrid nanofluid flow in convergent-divergent channels, and the results produced by the analytical data have also been strengthened and verified by the use of numerical data as well as data from the literature.

Bullet surface has a significant role in many engineering and industrial sectors, due to its wide fluid-based thermal management systems. The current approach emphasizes heat transfer mechanism in flow of ternary hybrid nanofluid over a bullet shape geometry. The integration of infinite shear rate viscosity-based model of Carreau explored the predictive capabilities of enhanced heat transport in ternary hybrid nanofluid. The purpose of the study is to seek an advanced predictive model that accurately captures the thermal prediction in ternary hybrid nanofluid under varying conditions of shear rate. By utilizing artificial neural networks (ANNs), the aim of this study is to simulate and analyze how these fluids respond to the combined effects of viscous dissipation, non-uniform heat sink source, thermal radiation, and infinite shear rate viscosity when interacting with bullet-shaped geometry. The physical model initially generated a set of partial differential equations, based on assumption in this study, and then this system is converted into ordinary differential equations (ODEs) using similarity transformations. This conversion simplifies the system into a more manageable form. The resulting ODEs are then numerically solved using the bvp4c method. The solutions obtained from this process are compiled into a dataset, which is then used to train through ANN. This neural network is designed to predict advanced solutions. The increase in velocity magnitude increases for stretching ratio and infinite shear rate parameter while it decreases for location parameter and velocity slip parameter. On the other hand, temperature profile decreased with augmentation in the numeric values of radiation parameter and Eckert numbers while it demonstrates the opposite trend for heat generation number and magnetic parameter. The rate of temperature increment is highest in ternary hybrid nanofluids compared to nanofluids and hybrid nanofluids.

The occurrence of hydrogen sulfide (H 2 S) gas gusher accidents is a worrying engineering disaster during tunnel construction travel through stratum adsorbed with H 2 S. To mitigate the risks associated with H 2 S, alkaline solutions are applied within the tunnel and injected into the rock mass ahead of the tunnel face to neutralize and eliminate the adsorbed H 2 S. Samples from the Huangjiagou tunnel in southwestern China are systematically investigated to understand the interaction between H 2 S-adsorbed limestone and calcium hydroxide (Ca(OH) 2 ) solutions at concentrations of 1, 3, and 5%. The results indicate that exposure of the limestone to Ca(OH) 2 solution leads to the erosion of aluminum silicate minerals and the subsequent precipitation of potassium feldspar crystals. The uniaxial compressive strength and modulus of elasticity of the limestone decreased by 48.82 and 28.31%, respectively, following an exponential trend as the concentration of Ca(OH) 2 solution increased. Additionally, an increase in the number of abrupt energy changes detected via acoustic emission is observed in limestone treated with higher concentrations of alkaline solutions. Energy evolution analysis indicates that alkaline-treated limestone exhibits significantly enhanced energy dissipation capacity during the loading process, making dissipative energy more likely to dominate.

The casting slurry determines the quality of the low-temperature co-fired ceramic (LTCC) green tapes. In the present investigation, large amplitude oscillatory shear (LAOS) is first exploited to characterize the rheological properties of casting slurry. Three kinds of casting slurries with different plasticizer contents were cast into green tapes and studied. Furthermore, comprehensive performance tests were carried out on the obtained green tapes, which showed matching nonlinear rheological properties with those of casting slurries, as obtained by LAOS tests. It revealed that the addition of an appropriate amount of plasticizer (plastic/binder = 0.5) can significantly improve the structural uniformity of the slurry. The green tapes at this content also had high tensile strength and excellent yield elongation. This study combines the internal microstructure of the casting slurry and the external comprehensive performance of green tapes according to LAOS tests. The optimal plasticizer content can be quickly and accurately obtained from the rheological theory.

This study explores the use of ten different fine materials to partially substitute cement, aiming to reduce greenhouse gas emissions from cement production. The materials include two types of fly ash (coarse and fine), blast furnace slag, silica fume (SF), three grades of limestone powder (coarse, medium, fine), and three grades of quartz powder. The physical, chemical, and mineralogical properties of these materials were analyzed, and 51 cement pastes were produced to study the effects of particle characteristics on packing density (PD) and fresh paste properties. Parameters such as particle size distribution, specific surface area, and particle shape were examined in relation to PD, flowability, and rheological behavior (yield stress and plastic viscosity). Both the De Larrard and centrifugal consolidation methods were used to measure PD. The experimental results revealed that the incorporation of coarse limestone powder increases the PD to 61.5%, while the addition of fine quartz powder decreases it to 55.1%. SF increases the PD up to 10% replacement; however, with excess content, it decreases due to the high fineness of the particles. Additionally, SF pastes exhibited the lowest flow spread, 112 mm (62% of the reference paste). Plastic viscosity increases with the use of fine fly ash and SF due to the high surface area and fine particles. Fly ash and limestone powder can be used to replace cement by up to 50% without deteriorating the rheological properties and flowability of cement pastes.

Segregation in self-consolidating concrete (SCC) can significantly impact the quality and structural integrity of concrete applications. Traditional methods for assessing segregation, such as the visual stability index and column segregation tests, often involve manual intervention, introducing subjectivity and delaying the assessment process. This study proposes a novel image-based approach using deep learning, specifically the YOLOv8 segmentation model, to quantify and assess segregation in fresh SCC mixes. Utilizing high-resolution images from slump flow tests, the model identifies critical indicators of segregation, including the mortar halo and aggregate pile. These features are evaluated with two newly introduced quantitative metrics: the mortar halo index ( I mh ) and the aggregate pile index ( I ap ). Experimental validation demonstrates high model precision (96.4%) and recall (85.6%), establishing it as a robust tool for on-site quality control. Furthermore, the study examines the relationship between segregation levels and compressive strength, revealing a strong correlation between increased segregation and reduced strength. The proposed feedback-based optimization strategy for mix proportions enables real-time adjustments to mitigate segregation risks. This approach enhances the objectivity and efficiency of segregation assessments, facilitating improved mix design and overall concrete performance on construction sites.

Evaluating the concentration of waste discharge across an exponential stretching surface is crucial for its environmental impact. In both ecological and industrial networks, wastewater management is crucial. The present study focuses on the prevention and analysis of the contamination of fluid assets by harmful chemicals. By analyzing these interactions, the present study examines steady, incompressible Casson fluid circulation under the influence of waste discharge concentration via a three-dimensional exponentially stretching sheet. The influence of thermophoresis, Brownian motion, and magnetic field was also examined. Governing equations can be transformed into the form of ordinary differential equations by utilizing the proper similarity operations. These simplified equations are resolved computationally using Runge–Kutta–Felhberg-45 and the shooting approach. The impacts of dimensionless parameters on each person’s profile are being examined using graphs. Furthermore, certain essential engineering coefficients are being explored. The predominant results are that in both directions, the magnetic and Casson fluid decreases velocities. Buoyancy constraint will increase the velocity while thermophoresis and Brownian contribute to an increase in temperature. An 8.04% increase in temperature is seen for thermophoresis. Skin friction increases with a significant increase in magnetic and Casson parameters, where thermophoresis and local pollutant decreases the rate of mass transmission.

The flow behavior of fire-fighting foams is an important factor in its performance as it largely determines how well and how fast the foam covers the burning fluid and seals it from oxygen. The flow characteristics, as well as the performance of such a foam is evaluated by a newly designed rheological cell and rheological experimental protocols mimicking a fire-fighting practice. Experiments are performed under conditions that apply while applying the foam (high shear of 10 s −1 , continuous fresh foam feed, which limits draining and coarsening) and conditions that apply once the foam is deposited (low shear of 0.5 s −1 , no foam feed allowing for draining and coarsening). This yields valuable insights. Very strong differences in flow behavior are observed changing from very well-flowing behavior on application to very viscous/stiff after deposition. Also, the shear-thinning character of foam flow was studied. After changing from a steady foam feed to a foam at rest situation, a transition period of complex flow behavior could be observed. This indicates that relaxation and restructuring processes of the foam bubbles that were deformed underflow are taking place. After this transition period, the effects of draining and coarsening become visible.

The power-law strain model used to characterize the first normal stress difference ( N 1 ) was checked here second based on the experimental linear viscoelastic properties, steady shear viscosities, and N 1 s of two cross-linked waxy corn starch pastes reported in 2003. Parameter f in a structured integral viscoelastic constitutive equation was obtained using the viscosities in the dynamic and steady shear experiments, and both the original and power-law strain models were employed to describe the normal component in the strain matrix of the equation and the N 1 s of the two pastes. The results showed that the three types of viscoelastic properties of the paste can be described well by the structured equation including the power-law strain model. In contrast, the descriptions of N 1 s based on the original strain model have huge deviation from the experiments for both pastes, which are similar to the first characterization of N 1 of corn starch paste with sucrose in 2022.

This study presents an innovative 3D-printed rheometric tool designed for the in situ analysis of phase transitions, providing a solution to the limitations of conventional rheometric methods. Standard techniques often face challenges in accurately capturing rapid gelation kinetics due to insufficient mixing capabilities and test preparation times. The new tool, adaptable to all conventional rheometers equipped with a disposable shuffle, incorporates a custom spiral channel geometry that allows immediate and efficient merging of two-component systems directly within the measurement system. The natural roughness of the 3D printed surface and the possibility of tuning plate and channel sizes make the tool even more promising. The instrument has been validated on three different systems: polyvinyl alcohol with borax, which undergoes rapid chemical gelation; sodium alginate with calcium chloride, which is characterized by rapid chemical gelation induced by ions; and Pluronic F68 solutions, which exhibit a concentration-dependent phase transition, from a crystal phase to a solution of randomly distributed spherical micelles. The 3D printed tool optimizes the study of chemorheological measurements in situ , capturing the evolution of viscoelastic properties in real time for the three cases.

The rheological and mechanical properties of bituminous binders vary significantly depending on the crude oil source. Consequently, the response of binders from different sources to polymer modification also differs. This study compares the rheological performance of B160/220 penetration-grade binders sourced from the Turkey-Batman and Iraq-Lanaz refineries, modified with styrene-butadiene-styrene (SBS), the most widely used polymer additive. To evaluate high-temperature performance, performance grade and frequency sweep tests were conducted using a dynamic shear rheometer. In addition to experimental assessments, the rheological behavior of the binders was analyzed using the Christensen–Anderson, Cross, and Carreau-Yasuda models. Time-temperature superposition principle master curves were generated to characterize their viscoelastic behavior. Zero shear viscosity (ZSV) values were determined using the Cross and Carreau-Yasuda models to examine the impact of polymer modification on binder viscosity. The findings indicate that the initial rheological properties of bitumen significantly influence its response to SBS modification. For instance, the G */sin δ value increased by up to 199% at 64°C with 4% SBS addition, while the softening point rose by 9.5°C compared to unmodified binders. Modelled ZSV values showed more than a sevenfold increase in some cases, especially in Iraqi binders. On the other hand, at −18°C, the m-value dropped to 0.282 in the B-SBS4 binder, indicating a potential risk of low-temperature cracking. While polymer modification improved the rheological properties of both bitumen types, its effectiveness varied depending on the source. Graphical abstract

This work aims to examine the influence of the shape factor on the hydrodynamic and thermal characteristics of ternary hybrid nanofluid flow over an inclined cylinder. The objective is to analyze the cumulative impacts of couple stress, porous medium, mixed convection, thermal radiation, mass suction, viscous dissipation, variable electrical conductivity, Joule heating, velocity and thermal slip conditions, and shape factor on flow dynamics, heat transfer enhancement, and entropy production. Utilize a dimensionless variable set to convert the governing partial differential equations into a system of interconnected ordinary differential equations, and then solve them numerically using the bvp4c function in MATLAB. The effects of dimensionless factors, including curvature parameter, porous medium, nanoparticle volume fraction, couple stress, inclination angle, mixed convection parameter, mass suction, Eckert number, Brinkmann number, thermal radiation, and magnetic parameters, are examined. The velocity profile and skin friction of various shapes (spherical, platelets, bricks, blades, cylinders) diminish as the couple stress parameter increases. The curvature parameter exhibits dual behavior in the velocity profile, whereas the temperature profile shows an increase. Mass suction enhances the velocity profile and diminishes the temperature profile. The Eckert number elevates the temperature profile while diminishing heat transfer. Enhancing nanoparticle values diminishes skin friction and augments heat transfer. Entropy generation escalates with higher values of nanoparticle volume fraction, Brinkman number, porous media, and radiation parameters. The morphology of platelets exhibits superior velocity profiles and enhanced heat transfer relative to other shapes. The findings of this research are very consistent with those of other studies.

Ectodermal dysplasia (ED) is a rare inherited disorder affecting embryonic ectoderm structures, leading to reduced development of skin appendages and certain eccrine glands. Displaying reduced salivation and impaired acoustic quality in males, ED offers a unique chance to study the role of laryngeal mucus in the phonation process. This study analyzed saliva rheology as a non-invasive substitute for laryngeal mucus to investigate potential causal relationships. Saliva samples from 36 ED patients and 99 controls were collected for 5 min following a 15 min abstention from eating, drinking, or smoking. The viscoelastic properties have been measured by a rheometer with a parallel plate system. Storage ( G ′) and loss ( G ″) moduli were recorded and compared between ED and controls. ED subjects exhibited significantly lower G ′ and G ″ at lower frequencies and strains, yet slightly higher values at increased frequencies and strains among males. These findings suggest reduced resistance of saliva to external forces for ED. Transferred to the laryngeal level, this behavior might impair the mucus’ retention rate on the vocal folds. The results also hint at altered hyaluronic acid content in ED, guiding further correlation studies investigating voice conspicuities.

This study presents an improved approach to correlating the Darcy friction factor for a fully developed laminar flow of Carreau fluids in circular pipes. The Carreau model stands as an essential representation of viscosity behavior and captures the complex rheological characteristics of polymeric fluids. By deriving a semi-analytical form of the Darcy friction factor, the study enables rapid and repeated evaluations across diverse flow conditions, facilitating the development of an explicit correlation. This improved correlation, built upon extensive data analysis, offers enhanced accuracy and broader applicability in predicting fluid behavior. The practical significance of this advancement is demonstrated through its successful application in calculating pressure drops for polymer melt and blood flows, highlighting its potential impact on industries ranging from materials processing to biomedical engineering. This work not only contributes to the theoretical understanding of non-Newtonian fluid dynamics but also provides a valuable tool for engineers dealing with complex fluid systems in circular pipes.

Self-compacting concrete (SCC), which can be placed and consolidated under its weight without any vibration effort, was first developed in 1988 to achieve durable concrete structures. Since then, a lot of research has been conducted in order to reduce the consumption of raw materials in SCC. Although coarse aggregate and design methods are known to influence concrete properties, there are still knowledge gaps that need to be filled. This study uses a new source of recycled coarse aggregate (RCA), namely the concrete panels of old large panel system buildings demolished in urban areas. The aim of the study is to verify the effect of this aggregate on the rheological and mechanical properties of SCC. To enhance the properties of SCC, the modified equivalent mortar volume (mEMV) method of designing a concrete mix was used. It has not been verified before for SCC, and a literature review suggests it has the potential to eliminate the drawbacks of ordinary equivalent mortar volume methods. The SCC that was used in the study is characterized by having a high viscosity and an average consistency. The hardened SCC used in the research was highly impacted by its mix design and RCA content. Both compressive strength and abrasion resistance decreased when the RCA content increased. However, using the mEMV method resulted in a 10 and 1% improvement in compressive strength and abrasion resistance, respectively. Graphical abstract

Chemical admixtures enhance concrete’s properties and performance, addressing diverse construction needs. This study investigates the effects of polyacrylamide (PAM) in combination with the accelerators calcium chloride (CaCl 2 ) and triethanolamine (TEA) on the early hydration of cement, with a particular focus on static yield stress. To assess the impact of these admixtures on hydration kinetics and material properties, we employed various analytical methods, including calorimetric tests, thermogravimetric analysis, X-ray diffraction, inductively coupled plasma experiments, and the penetration method. The results indicate that CaCl 2 accelerates the early hydration of C 3 S, promoting the formation of C–S–H and CH while facilitating the conversion of AFt to Friedel’s salt. PAM helps to regulate AFt behavior, reinforcing the beneficial effects of CaCl 2 . Additionally, TEA influences the hydration of C 4 AF, enhancing AFt precipitation, while higher dosages modify early hydration dynamics by delaying C 3 S hydration. The interaction between PAM and TEA enhances clinker dissolution, significantly increasing static yield stress through complexation reactions mediated by iron ions. These findings highlight the potential for tailored admixture formulations that combine PAM with traditional accelerators to optimize cement hydration and improve material performance.

Bacterial biofilms present significant challenges across microbiology, environmental science, water management, and healthcare. This study employs Quartz crystal microbalance with dissipation monitoring (QCM-D) and interfacial rheology system (IRS) for in situ analysis of Escherichia coli biofilm growth and viscoelastic properties. By monitoring biofilm development at both bulk and micro scales in real-time, we identified three distinct growth phases: surface attachment and initial growth, maturation, and dispersion. Optimal biofilm formation occurred in Luria-Bertani medium medium at 5% (v/v) inoculation, as indicated by high complex viscosity and modulus values of 5.38 mPa·s and high complex modulus of 169.13 kPa. IRS data corroborated these findings, showing consistent elastic and viscous behavior patterns, with the storage modulus ( G ′) reaching 0.057 Pa·m and loss modulus ( G ″) peaking at 0.016 Pa·m during the maturation phase. Our results highlight the sensitivity of QCM-D in measuring biofilm properties and the effectiveness of using combined micro- and macro-scale methods for comprehensive biofilm characterization. Graphical abstract

This study aims to enhance the sensory evaluation of skin creams by using machine learning to predict sensory attributes based on instrumental parameters, addressing the limitations of conventional methods. Extensive instrumental parameters, including rheological, tribological, and textural properties of ten different skin creams, were collected, and 22 sensory attribute scores were obtained from trained expert evaluations. Pearson’s correlation analyses and multiple supervised learning algorithms were applied to establish relationships between each sensory attribute and the instrumental parameters, respectively. The results showed that K-Nearest Neighbors, AdaBoost, and LightGBM were the algorithms with the best performance for most sensory attributes, and the overall model achieved over 95% prediction accuracy for 80% of the sensory dimensions, demonstrating strong reproducibility and accuracy in the verification test, with predicted sensory scores closely aligning with actual values. However, issues such as model overfitting, discrepancies between training and testing data distributions, and increased noise in the testing data, which result in the residuals from the testing set exceeding those from the training set, need to be further addressed in future research. In summary, this data-driven approach offers a more efficient, accurate, and standardized method for sensory evaluations, with the potential to support the development and optimization of skincare products.

In order to investigate the impact of flaw inclination angles (FA) and crack arrest holes on the mechanical characteristics and failure modes of combined pre-cracked granite, uniaxial compression simulation tests were conducted on specimens with different FA α and crack arrest holes using Particle Flow Code (PFC). These crack arrest holes were set at a fixed position of 5 mm from the tip of the straight crack. The simulation results showed that although crack arrest holes can change the direction of the failure mode, they had no effect on the crack initiation mode. The stress distribution under crack initiation strength was studied by analyzing the stress field through measurement circles in the PFC program. Especially, the tensile stress concentration zone determines the crack initiation mode, while the compressive stress concentration zone influences the failure mode. Based on the maximum circumferential stress criterion, the relationship between the crack initiation angle θ and the stress concentration zone was established, and a new arrangement method for crack arrest holes was proposed. This method can increase the peak strength of specimens with FA α = 0°, 45°, and 60° by 14.16, 14.12, and 14.11%, respectively, providing valuable insights for enhancing the stability of underground fractured rock masses.

Understanding the rheological properties of protein melts is critical in the design of meat analogues and the formation of texturised products from plant-based proteins. This study investigated the influence of temperature, moisture content (MC) and protein concentration on the rheological properties of pea protein isolate and pea fibre blends. The blends were chosen as an experimental space where it is possible to extrude fibrous meat analogues using high-moisture extrusion. Mechanical spectra by small amplitude oscillatory shear were determined using conventional rheometry and were compared to closed cavity rheometry (CCR) to extend the available temperature range. All blends behaved as polymer melts in the rubbery region with moduli increasing with frequency, and storage modulus larger than loss modulus for temperature 40–90°C, MC 54–63%, protein concentration 75–85%. Complex viscosity was strongly shear thinning. The relative influence of the parameters from additive and linear mixed models showed an influence of temperature > MC > concentration. The increase of modulus with concentration was quite weak and not statistically significant. The behaviour of the complex modulus was explained well with an Arrhenius-type log-linear mixed model. Conventional rheometry agreed well with CCR, showing an exponential decrease of moduli between 40 and 130°C.

Extrusion-based three-dimensional (3D) food printing is an emerging technique, relying crucially on the rheological behavior of the ink for success. This study aims to understand the rheological properties of the paste-like 3D food printing inks near the processing conditions. Experimental artifacts, particularly the edge fracture at high deformations, are a common challenge when working with pastes. While steady shearing is the most informative measurement, it is not practical due to experiential artifacts. We characterized the rheology of these inks with oscillatory measurements, described the deformation response with a constitutive model, and translated the information from oscillatory testing to steady shearing. The novel constitutive model is a generalization of the Oldroyd-B model using a shear-rate-dependent viscosity following Herschel Bulkley. The model parameters were estimated by non-linear least-squares fitting. The constitutive model successfully predicted the sample response at large deformations and the steady-shear flow response, such as those encountered in 3D food printing. The applicability of the methodology can be extended for different materials that are challenging to characterize. We explored methods to measure the rheological properties of paste-like materials prone to edge fracture, aiming for an accurate description of their response under processing.

The ability to measure protein functionality is critical for the development of plant-based products, particularly with respect to gelation behavior, which is vital for food structure and texture. Small amplitude oscillatory shear (SAOS) tests remain the standard for monitoring protein gelation; however, these methods are costly, time-consuming, and require physical contact with the sample. Laser speckle rheology, an optical-based technique, offers a contactless alternative by assessing rheological properties through speckle pattern fluctuations. In this work, we present a simple laser speckle rheology setup, utilizing a diode laser and a digital camera, to monitor rheological changes during the rennet coagulation of milk. We use a viscoelasticity index (VI), derived from a two-dimensional linear correlation, to quantify speckle pattern fluctuations. The laser speckle rheology method is compared with conventional SAOS rheology. Results demonstrate that key characteristics of the coagulation process, including coagulation and gelation times, are temporally aligned between the two methods. Furthermore, the VI allows for the comparison of the complex modulus in samples with similar compositions under consistent acquisition parameters. These findings underscore the potential of laser speckle rheology as a cost-effective, rapid, and contactless approach for capturing protein gelation, providing an alternative to conventional shear rheological methods.

Walnut glutelin is a storage protein of high nutritional value, but its composition, structure, and applications in foods have not been fully studied. In this work, walnut glutelin was obtained using the Osborne fractionation method and identified by liquid chromatography-tandem mass spectrometry. The main components of the extracted walnut glutelin were legumin B-like, 11S globulin-like, 11S globulin seed storage protein Jug r 4, and 11S globulin seed storage protein 2-like. Besides, the adsorption behaviors of walnut glutelin and its linear as well as nonlinear rheological properties at the air–water interface were investigated. Results showed that at a low concentration of 10 μg/mL (<critical aggregation concentration), walnut glutelin reduced the interfacial tension to 59 mN/m after adsorption, permeation, and rearrangement at the air–water interface, suggesting that walnut glutelin has the ability to stabilize the air–water interface. Meanwhile, the solid-like interfacial film formed by walnut glutelin exhibited a high elastic modulus (35–45 mN m −1 ) and good mechanical properties over the tested amplitudes (8–40%). These findings demonstrate that walnut glutelin is a promising stabilizer for foamed food products.

This study investigates the microstructure and rheological properties of faba bean isolate (FBI) stabilized foams at pH 7 and 4 (addition of sugar or not), and compares with egg white (EW) under both unheated and heated foams. Unheated foams at pH 4 showed higher overrun, stability and more rigid structure, compared to those obtained at pH 7, due to the presence of larger protein aggregates surrounding the lamella structure. In contrast, EW foams displayed the highest overrun, but not stable as FBI foam at pH 4. After heating, FBI foams at pH 7 were nearly unaffected, whereas at pH 4, heating induced the formation of very large structures of aggregated proteins and caused the merging of air bubbles. For EW, heating seems to induce structural rearrangements with large protein aggregates closely attached to whole foam lamella. Sugar addition to FBI at pH 4 decreased the overrun and the stiffness, and the rate of liquid drainage. Upon heating, sugar contributed to maintaining a stable foam with higher G ′ and spherical bubbles. The toughest foams are the FBI at pH 4 after microwave heating. This study highlights the importance of studying the foaming properties of plant proteins under relevant environmental and processing condition. Graphical abstract

The ongoing shift towards replacing traditional animal-based foods with plant-based alternatives presents several technical challenges. In particular, there is a change in swelling properties of soils and cleaning behavior of production lines. Increased quantities of water, chemicals, and heat are often used to ensure food safety. A comparison of changes in mechanical properties of different food soils combined with cleaning liquids enables cleaning to be tailored to specific products while saving resources. Consequently, a rheological methodology for analysis of swelling soil layers immerged in cleaning liquids was improved with regard to efficiency of measurements, the adjustment of moisture content in the soil layer, and the insight into the time dependence of swelling. With the CP method, the measuring period on the rheometer could be reduced to approx. one tenth. Drying soil layers in a climate chamber allows for reproducible soil layers and moisture content adjustment, enabling analysis of soil layers with different drying degrees. Due to compression-related effects, the time dependency of the swelling can only be understood to a limited extent through measurements in the immersed state after different swelling times. Nevertheless, the improved method offers the potential to select suitable cleaning liquids and cleaning cycle. Graphical abstract

Thermal transitions, such as crystallization or relaxation, in heterogeneous materials are complex and occur at different length and time scales. Several devices are necessary for their analysis, leading to varying boundary conditions and multiple specimens across measurements. This study investigated the thermal transitions of oleogels, designed to replace animal products, composed of rapeseed oil with 20% w/w oleogelator. Three oleogels with either rice bran wax (RBX), ethyl cellulose (EC), or a 1:1 mixture of both were analyzed. To capture dynamic mechanisms at multiple length and time scales, a simultaneous multiscale experiment was conducted on a single sample under the same conditions. Accordingly, Raman and dielectric spectroscopy were coupled with dynamic mechanical analysis (DMA) over a temperature range of 150 to −10°C. Differential scanning calorimetry was also performed to validate the results. DMA revealed a gradual glass transition in EC oleogels at ∼120°C. Raman spectroscopy complemented these findings, providing detailed molecular insights into RBX crystallization starting at ∼60°C until ∼5°C, not detectable with DMA. Dielectric spectroscopy extended the frequency range of DMA and revealed a temperature-activated relaxation process > 500 Hz at ∼5°C in RBX-containing samples. This study demonstrated the potential of multiscale analyses to link mechanical, dielectric, and chemical processes to complex thermal processes occurring in soft materials such as oleogels. Furthermore, these results provide a basis for improving the applicability of plant-based fat substitutes.

Typically, the geopolymer has a semi-crystalline structure and is amorphous in form. The structural backbone of the geopolymer theoretically relies on aluminosilicate (–Si–O–Al–O‒) ₙ sources, which are adequately found in nontoxic bio-sources. Sugarcane bagasse ash (SCBA) is rich in carbon and (‒Si–O–Al–O‒) ₙ and is widely available as a nontoxic biowaste material. Therefore, in this study, without any additives, the SCBA was used as a base intermediate for geopolymer synthesis. This study involved preparing alkaline activators (AAs) at temperatures ranging from 5 to 60°C. Later, the study’s purpose was to investigate the influence of these AAs on the rheological properties of geopolymer dope solutions. The apparent viscosity and shear stress behavior of the 30 and 50% AA solutions made at 5 and 60°C were higher than those of the ambient circumstances (AA and water ambient conditions). A solution with a 50% sodium hydroxide (NaOH) content yields comparable outcomes. The findings show that a 50% NaOH solution demonstrates higher viscosity and shear stress compared to a 30% NaOH solution. Geopolymer dope solutions also showed the same results. The viscous geopolymer solution results from the formation of a rigid aluminosilicate oligomer and monomer network during geopolymerization. The geopolymer dope solution, prepared under different conditions, showed significant changes in its rheological characteristics. Changes in the processing conditions of geopolymer dopes revealed some significant reactivity in the geopolymerization process, which most likely led to the formation of product clusters. The modified Bingham model and the Herschel–Bulkley model are suitable for evaluating the rheological behavior of the SCBA geopolymer dope solution.

Among the various bitumen additives, crumb rubber (CR) derived from waste tires stands out due to its economic and environmental advantages. The effectiveness of CR modification is influenced by several factors, including temperature, mixing speed, duration, and particle size. Excessive mixing speed and prolonged mixing in laboratory conditions can lead to the depolymerization of CR, which may adversely affect the elastic properties of the bitumen. In contrast, plant-scale production typically follows a more rapid and simplified process. In this study, bitumen containing 8% CR, modified under plant and laboratory conditions with varying mixing speeds and durations, was rheologically analyzed. Temperature and frequency sweep tests were conducted using a dynamic shear rheometer, and master curves were generated to evaluate the bitumen’s viscoelastic behavior through various rheological models. The findings indicate that higher mixing speeds and extended mixing durations in laboratory conditions increase bitumen stiffness; however, excessive mixing leads to depolymerization, thereby reducing its elastic properties. The laboratory-produced CR modification demonstrates significantly superior performance compared to that generated in the plant. Furthermore, response surface methodology optimization analysis results indicate that the ideal conditions for mixing are a speed range of 3,000–4,000 rpm and a duration of 45–60 min.