Band 2, Heft 3

Dramatic advances are in the horizon resulting from rapid pace of development of several technologies, including, computing, communication, mobile, robotic, and interactive technologies. These advances, along with the trend towards convergence of traditional engineering disciplines with physical, life and other science disciplines will result in the development of new interdisciplinary fields, as well as in new paradigms for engineering practice in the coming intelligence/convergence era (post-information age). The interdisciplinary fields include Cyber Engineering, Living Systems Engineering, Biomechatronics/Robotics Engineering, Knowledge Engineering, Emergent/Complexity Engineering, and Multiscale Systems engineering. The paper identifies some of the characteristics of the intelligence/convergence era, gives broad definition of convergence, describes some of the emerging interdisciplinary fields, and lists some of the academic and other organizations working in these disciplines. The need is described for establishing a Hierarchical Cyber-Physical Ecosystem for facilitating interdisciplinary collaborations, and accelerating development of skilled workforce in the new fields. The major components of the ecosystem are listed. The new interdisciplinary fields will yield critical advances in engineering practice, and help in addressing future challenges in broad array of sectors, from manufacturing to energy, transportation, climate, and healthcare. They will also enable building large future complex adaptive systems-of-systems, such as intelligent multimodal transportation systems, optimized multi-energy systems, intelligent disaster prevention systems, and smart cities.

This review discusses the use of scaffolds in tissue engineering and summarises the means by which they might be fabricated. The review identifies the main features a scaffold should have, and discusses the progress that has been made towards obtaining these targets. In particular, the review focuses on inkjet printing as a viable production route and discusses why this additive manufacturing technique holds considerable appeal and promise. The article concludes with an overview of the current challenges in this field and reviews the different types of material that can be used for scaffolds.

The energy output performance and thermal stability of organic energetic materials have a strong dependence on the porosity, particle morphology, and micro-scale crystal structure. This paper reviews the growth habit of pure pentaerythritol tetranitrate (PETN) crystals and the effect of metal impurities on microcrystal morphology of PETN films. The pure crystal growth shows that PETN molecules diffuse on the surface and nucleate in a two-dimensional layer-by-layer fashion; the final structure is controlled by the deposition flux. Also, the effect of metal cation impurities has a strong impact on the thermal stability and crystal structure, and is dependent on the doping level.

The effect of boron (between 0.06 and 0.11 wt%) on the microstructure, hardness and compression properties of cast Ti-6Al-4V was investigated. Compression properties were examined in the temperature range from room temperature to 1000°C. It was found that the addition of boron refines the as-cast microstructure in terms of prior beta grain size and alpha colony size. This microstructural refinement led to an increase in compressive yield strength from room temperature up to 700°C. Three different strain rates (0.001, 0.1 and 1 s−1) were evaluated during compression testing from which it was found that the compressive yield strength decreased with decreasing strain rate from 600°C up to the beta transus temperature.

The article discusses the results of tests on the impact of long-term stress relief annealing at 620–650°C and cooling at a rate of 10°C/h on the mechanical properties of low-alloy weld deposits of covered electrodes containing 1.5–3% Ni, 0–0.3% Mo and 0.01–0.03% P. The article also contains information on the most advantageous nickel content for obtaining the highest impact energy (KV) values in subzero temperatures. X-ray structural analysis revealed that such weld deposits contain solely Fe3C carbides, which prevents the impact of molybdenum carbides on the change of KV. The study also confirmed the adverse effect of phosphorus on the weld deposit impact energy after long-lasting heat treatment.

Nanomaterials play an important role in modern science and engineering. The ability to fabricate nanomaterials with high quality and low cost is a primary stage for further discovering their applications. This research article presents a facile fabrication of Cu2O nanowires on Cu substrate. It was found that simply heating Cu in air leads to the growth of Cu2O nanowires. The Cu2O nanowires are aligned in one direction and vertically grown on the Cu substrate. The growth process of nanowires was tracked by SEM and the root at the initial stage was observed by HRTEM. The access to oxygen is critical to the growth of Cu2O nanowires and the patterned nanowire arrays can be readily fabricated by using a mask. The method reported here offers a great potential route toward a large scale manufacture of Cu2O nanowires.

Head motion during Computed Tomographic (CT) brain imaging studies can adversely affect the reconstructed image through distortion, loss of resolution and other related artifacts. In this paper, we propose a marker based innovative approach to detect and mitigate motion artifacts in three dimensional cone-beam brain CT systems without using any external motion tracking sensor. Motion is detected using correlations between the adjacent projections. Once motion is detected, motion parameters (i.e. six degrees-of-freedom of motions) are estimated using a numerical optimization technique. Artifacts, caused by motions, are mitigated by using a modified form Feldkemp-Davis-Kress (FDK) algorithm which uses the estimated motion parameters in back-projection stage. The proposed approach has been evaluated on a modified three-dimensional Shepp-Logan phantom with a range of simulated motions. Simulation results demonstrate a quantitative and qualitative validation of motion detection and artifacts mitigation technique.

In this paper, a single-stage deep sub-micron wideband amplifier (LNA) using a reactive resonance tank and passive port-matching techniques is demonstrated operating in the microwave frequency range (K band). A novel power-efficient bandwidth (BW) regulation technique is proposed by incorporating a small impedance in the resonance tank of the amplifier configuration. It manifests a forward gain in the range of 5.9–10.7 dB covering a message bandwidth of 10.6–6.3 GHz. With regulation, input-output reflection parameters (S 11, S 22) and noise figure can be manipulated by −12.7 dB, −22.7 dB and 0.36 dB, respectively. Symmetric regulation is achieved for bandwidth and small signal gain with respect to moderate tank impedance (36.5% and −26.8%, respectively) but the effect on noise contribution remains relatively low (increase of 7% from a base value of 2.39 dB). The regulated architecture, when analyzed with 90 nm silicon CMOS process, supports low power (9.1 mW) on-chip communication. The circuit is tested with a number of combinations for tank (drain) impedance to verify the efficiency of the proposed technique and achieves better figures of merit when compared with published literature.

This article features results from a fuzzy controller with fuzzy dynamic correction for the non-linear control of objects with variable parameters. The methods described herein have been used on a fuzzy proportional-differential (PD) controller, and our results show that fuzzy dynamic correction can reduce overshoot and shorten the settling time of the controlled parameters.

This article presents the method of comparative assessment of the grinding wheel cutting ability in the plunge grinding kinematics. A new method has been developed to facilitate multicriterial assessment of the working conditions of the abrasive grains and the bond bridges, as well as the wear mechanisms of the GWAS, which occur during the grinding process, with simultaneous limitation of the workshop tests range. The work hereby describes the methodology of assessment of the grinding wheel cutting ability in a short grinding test that lasts for 3 seconds, for example, with a specially shaped grinding wheel, in plunge grinding. The grinding wheel macrogeometry modification applied in the developed method consists in forming a cone or a few zones of various diameters on its surface in the dressing cut. It presents an exemplary application of two variants of the method in the internal cylindrical plunge grinding, in 100Cr6 steel. Grinding wheels with microcrystalline corundum grains and ceramic bond underwent assessment. Analysis of the registered machining results showed greater efficacy of the method of cutting using a grinding wheel with zones of various diameters. The method allows for comparative tests upon different grinding wheels, with various grinding parameters and different machined materials.

Unsteady pressure distributions of a two-dimensional super-critical wing while it was fluttering were measured in the transonic flow regime. The results were compared with those by the Navier-Stokes code which includes wind-tunnel wall effects. Although there were discrepancies between the experimental results and the analytical model for the pressure phase delay distribution, no disagreements were observed for the pitching first harmonics provided that there was no large flow separation. In the tests, the flutter was forced to be suppressed soon after its onset before it reached a limit cycle oscillation (LCO) where the amplitude of the pitching angle was supposed to be over 2 degrees.

The present paper is concerned with the study of the propagation of acceleration waves along the characteristic path in a non-ideal gas flow with effect of radiative heat transfer. It is shown that a linear solution in the characteristic plane can exhibit non-linear behavior in the physical plane. It is also investigated as to how the radiative heat transfer under the optically thin limit will affect the formation of shock in planer, cylindrical and spherically symmetric flows. We conclude that there exists critical amplitude such that any compressive waves with initial amplitude greater than the critical one terminate into shock waves while an initial amplitude less than the critical one results in the decay of the disturbance. The critical time for shock formation has been computed. In this paper we also compare/contrast the nature of solution in ideal and non ideal gas flows.

Response surface methodology (RSM) involving the central composite design (CCD) was employed to optimize three important process variables for the decolourization of synthetic dye solutions containing Remazol Turquoise Blue (RTB) and Reactive Black 5 (RB5) with isolated bacterial strain Pseudomonas sp. The interaction between three variables i.e. Initial concentration of dye, carbon source and nitrogen source were studied and modeled. According to the Analysis of variance (ANOVA) results the predicted results were found to be in good agreement with experimental results (R 2: 0.9726; Adj R 2: 0.9480 for RTB and R 2: 0.9789; Adj R 2: 0.9750 for RB5) which indicated excellent evaluation of experimental data from the second order polynomial regression model. Mathematical models were developed by the proposed system, for each process variable showed the effect of each factor and their interactions on biodecolourization process. The optimum concentrations of Dye, Carbon source, and Nitrogen source were found to be 20 mgL−1, 1.5 g/L and 1.5 g/L, respectively for RTB and RB5 to obtain maximum dye removing capacity. Predicted values were validated with experimental results, which indicated appropriateness of the employed model and the success of RSM.

In this study, the sorption of phenol drifts was studied by performing batch kinetic sorption experiments. The equilibrium kinetic data was analyzed using the pseudo-second-order kinetic model. Fowler-Guggenheim model gives a perfect fitting with the isotherm data. The influence of porous structure of a zeolite particle on phenol adsorption from aqueous solutions is analyzed and discussed. The adsorption for phenol drifts on zeolite was proved to be an exothermic process. Thus the solubility of the phenolic compound and the pH of the solution play also an important role in adsorption phenomena. The relative affinity of the phenolic compound toward the zeolite was related to the electron donor-acceptor complexes that were formed between the basic sites on the zeolite (oxygen) and hydrogens (acidic site) of the phenols. Finally zeolite seems to be an efficient adsorbent; it can be easily regenerated by methanol leaching.

Steel fiber reinforced self-compacting concrete (SFRSCC) is a relatively new composite material which congregates the benefits of the self-compacting concrete (SCC) technology with the profits derived from the fiber addition to a brittle cementitious matrix. Steel fibers improve many of the properties of SCC elements including tensile strength, ductility, toughness, energy absorption capacity, fracture toughness and cracking. Although the available research regarding the influence of steel fibers on the properties of SFRSCC is limited, this paper investigates the bond characteristics between steel fiber and SCC firstly. Based on the available experimental results, the current analytical steel fiber pullout model (Dubey 1999) is modified by considering the different SCC properties and different fiber types (smooth, hooked) and inclination. In order to take into account the effect of fiber inclination in the pullout model, apparent shear strengths (τ (app)) and slip coefficient (β) are incorporated to express the variation of pullout peak load and the augmentation of peak slip as the inclined angle increases. These variables are expressed as functions of the inclined angle (ϕ). Furthurmore, steel-concrete composite floors, reinforced concrete floors supported by columns or walls and floors on an elastic foundations belong to the category of structural elements in which the conventional steel reinforcement can be partially replaced by the use of steel fibers. When discussing deformation capacity of structural elements or civil engineering structures manufactured using SFRSCC, one must be able to describe thoroughly both the behavior of the concrete matrix reinforced with steel fibers and the interaction between this composite matrix and discrete steel reinforcement of the conventional type. However, even though the knowledge on bond behavior is essential for evaluating the overall behavior of structural components containing reinforcement and steel fibers, information is hardly available in this area. In this study, bond characteristics of deformed reinforcing steel bars embedded in SFRSCC is investigated secondly.