Advances in Materials Science and Engineering The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Correlation between Electrical Properties and Potentiometric Response of CS-Clay Nanocomposite Membranes Sun, 24 May 2015 09:52:45 +0000 The aim of this work is to study the relationship between electrical, structure, and potentiometric response to nitrate anions using Ion Selective Electrodes (ISE). These ISE are based on chitosan-montmorillonite nanocomposite membranes with different content of montmorillonite. Membrane properties have been studied using SEM, FTIR, and impedance spectroscopy measurements. With the advent of impedance spectroscopy one is allowed to obtain the DC conductivity dependence on montmorillonite concentration and the percolation threshold. Additionally, the potentiometric response to nitrate anions of ISE based on chitosan-clay nanocomposite has been investigated. It is shown that the properties and performance of these membrane electrodes depend upon the clay wt% and that the best sensitivity to nitrate ions (with detection limit 7 10−5 M) is obtained near the percolation concentration ca. 8 ± 2.5 wt% of clay. This observation is traceable to higher clay content (higher agglomeration) that tends to decrease the intercalation and absorption of the number of chitosan chains in the interlayer space of montmorillonite. M. Oviedo Mendoza, O. Arias de Fuentes, E. Prokhorov, G. Luna Barcenas, and E. Padilla Ortega Copyright © 2015 M. Oviedo Mendoza et al. All rights reserved. High-Entropy Alloys Thu, 21 May 2015 07:13:27 +0000 Yong Zhang, Jien-Wei Yeh, Jian F. Sun, Jun P. Lin, and Ke-Fu Yao Copyright © 2015 Yong Zhang et al. All rights reserved. Theoretical Analysis and Experimental Researches regarding the Asymmetrical Fluid Flow Applied in Aeronautics Tue, 19 May 2015 13:57:48 +0000 The current paper has been written in order to find the best solutions to replace the antitorque rotor of single-rotor helicopters, with removal of its disadvantages through the Coandă Effect. This would significantly increase the flight performance. The research mainly aims at obtaining a controlled lateral force due to Coandă flows through the tail boom, a force which would be useful for the stabilization needed because of the lifting rotor during the flight of single-rotor helicopters. Ionică Cîrciu, Doru Luculescu, Vasile Prisacariu, Eduard Mihai, and Constantin Rotaru Copyright © 2015 Ionică Cîrciu et al. All rights reserved. Ellipsometric Analysis of Cadmium Telluride Films’ Structure Mon, 18 May 2015 07:25:39 +0000 Ellipsometric analysis of CdTe films grown on Si and CdHgTe substrates at the “hot-wall” epitaxy vacuum setup has been performed. It has been found that ellipsometric data calculation carried out by using a simple one-layer film model leads to radical distortion of optical constants spectra: this fact authenticates the necessity to attract a more complicated model that should include heterogeneity of films. Ellipsometric data calculation within a two-layer film model permitted to conclude that cadmium telluride films have an outer layer that consists of the three-component mixture of CdTe, cavities, and basic matter oxide. Ratio of mixture components depends on the time of deposition, that is, on the film thickness. The inner layer consists of cadmium telluride. Anna Evmenova, Volodymyr Odarych, Mykola Vuichyk, and Fedir Sizov Copyright © 2015 Anna Evmenova et al. All rights reserved. An Atomic Study of Substructures Formed by Shear Transformation in Cast γ-TiAl Sun, 17 May 2015 14:13:16 +0000 Substructures and microsegregation of γ/γ laths are analyzed with HRTEM and HAADF-STEM. Results show that the substructures are generated during evolution of shear transformation on the plane of γ lath. At the beginning, shear transformation evolves in a single γ lath, and a superstructure intrinsic stacking fault (SISF) forms in the γ lath. After the formation of the SISF, the shear transformation may evolve in two different ways. If the shear transformation evolves into neighboring γ laths, the SISF also penetrates into neighboring γ laths and a ribbon of SISFs forms. If shear transformation continues to evolve in the original lath, complex substructures begin to form in the original. If shear transformation in the original lath is homogeneous and complete, secondary twin forms which may further grow into twin intersection. Incomplete shear transformation could not form secondary twins but generates a high concentration of planar faults on the plane. These planar faults may further penetrate the γ/γ lath interface, grow into adjacent laths, and form a ribbon of planar faults. Hanlei Zhang, Hongchao Kou, Xiaolei Li, Bin Tang, and Jinshan Li Copyright © 2015 Hanlei Zhang et al. All rights reserved. Optimization of Bending Process Parameters for Seamless Tubes Using Taguchi Method and Finite Element Method Sun, 17 May 2015 11:23:18 +0000 The three-dimensional tube (or pipe) is manufactured by CNC tube bending machine. The key techniques are determined by tube diameter, wall thickness, material, and bending radius. The obtained technique through experience and the trial and error method is unreliable. Finite element method (FEM) simulation for the tube bending process before production can avoid wasting manpower and raw materials. The computer-aided engineering (CAE) software ABAQUS 6.12 is applied to simulate bending characteristics and to explore the maximum stress and strain conditions. The Taguchi method is used to find the optimal parameters of bending. The confirmation experiment is performed according to optimal parameters. Results indicate that the strain error between CAE simulation and bending experiments is within 6.39%. Jui-Chang Lin and Kingsun Lee Copyright © 2015 Jui-Chang Lin and Kingsun Lee. All rights reserved. Spatial Distribution of Voids in Insulating Concrete Analyzed by Micro-CT Images and Probability Functions Sun, 17 May 2015 11:15:20 +0000 Insulating concrete is a multiphase material designed for reduced thermal conductivity, and the void distribution in concrete strongly affects its physical properties such as mechanical response and heat conduction. Therefore, it is essential to develop a method for identifying the spatial distribution of voids. To examine the voids of insulating concrete specimens, micro-CT (computed tomography) images can be effectively used. The micro-CT images are binarized to visualize the void distribution and stacked to generate 3D specimen images. From the obtained images, the spatial distribution of the voids and the microscopic constituents inside the insulating concrete specimens can be identified. The void distribution in the material can be characterized using low-order probability functions such as two-point correlation, lineal-path, and two-point cluster functions. It is confirmed that micro-CT images and low-order probability functions are effective in describing the relative degree of void clustering and void connectivity in insulating concrete. Sang-Yeop Chung, Tong-Seok Han, and Yong-Woo Kim Copyright © 2015 Sang-Yeop Chung et al. All rights reserved. Characterization of Moisture Diffusion in Cured Concrete Slabs at Early Ages Sun, 17 May 2015 07:19:17 +0000 The objective of this paper is to investigate the characterization of moisture diffusion inside early-age concrete slabs subjected to curing. Time-dependent relative humidity (RH) distributions of three mixture proportions subjected to three different curing methods (i.e., air curing, water curing, and membrane-forming compounds curing) and sealed condition were measured for 28 days. A one-dimensional nonlinear moisture diffusion partial differential equation (PDE) based on Fick’s second law, which incorporates the effect of curing in the Dirichlet boundary condition using a concept of curing factor, is developed to simulate the diffusion process. Model parameters are calibrated by a genetic algorithm (GA). Experimental results show that the RH reducing rate inside concrete under air curing is greater than the rates under membrane-forming compound curing and water curing. It is shown that the effect of water-to-cement (w/c) ratio on self-desiccation is significant. Lower w/c ratio tends to result in larger RH reduction. RH reduction considering both effect of diffusion and self-desiccation in early-age concrete is not sensitive to w/c ratio, but to curing method. Comparison between model simulation and experimental results indicates that the improved model is able to reflect the effect of curing on moisture diffusion in early-age concrete slabs. Xiao Zhang and Hongduo Zhao Copyright © 2015 Xiao Zhang and Hongduo Zhao. All rights reserved. Simulation of Bimetallic Bush Hot Rolling Bonding Process Wed, 13 May 2015 12:32:39 +0000 Three-dimensional model of bimetallic bush was established including the drive roller and the core roller. The model adopted the appropriate interface assumptions. Based on the bonding properties of bimetallic bush the hot rolling process was analyzed. The optimum reduction ratio of 28% is obtained by using the finite element simulation software MARC on the assumption of the bonding conditions. The stress-strain distribution of three dimensions was research assumptions to interface deformation of rolling. At the same time, based on the numerical simulation, the minimum reduction ratio 20% is obtained by using a double metal composite bush rolling new technology from the experiment research. The simulation error is not more than 8%. Yaqin Tian and Qingxue Huang Copyright © 2015 Yaqin Tian and Qingxue Huang. All rights reserved. Effects of WMA Additive on the Rheological Properties of Asphalt Binder and High Temperature Performance Grade Mon, 11 May 2015 11:24:24 +0000 Sasobit additives with different dosages were added into 70# and 90# virgin asphalt binders to prepare WMA binders. The rheological properties, including and δ, were measured by using DSR at the temperature ranging from 46°C to 70°C, and the effects of temperature, additive dosage and aging on , critical temperature, and H-T PG were investigated. The results indicate that WMA additive improves but reduces δ, and the improvement on 70# virgin binder is more significant. exponentially decreases with the increasing temperature but linearly increases with the increasing additive dosage. Aging effect weakens the interaction between binder and additive but significantly increases the binder’s viscosity; that is why is higher after short-term aging. In addition, the critical temperature increases with the increasing additive dosage, and the additive dosage should be more than 3% and 5% to improve H-T PG by one grade for 70# and 90# virgin binder, respectively. Jiupeng Zhang, Guoqiang Liu, Li Xu, and Jianzhong Pei Copyright © 2015 Jiupeng Zhang et al. All rights reserved. Thermomechanical Fractional Model of Two Immiscible TEMHD Mon, 11 May 2015 09:11:30 +0000 We introduce a mathematical model of unsteady thermoelectric MHD flow and heat transfer of two immiscible fractional second-grade fluids, with thermal fractional parameters and mechanical fractional parameters , . The Laplace transform with respect to time is used to obtain the solution in the transformed domain. The inversion of Laplace transform is obtained by using numerical method based on a Fourier-series expansion. The numerical results for temperature, velocity, and the stress distributions are represented graphically for different values of and . The graphs describe the fractional thermomechanical parameters effect on the case of two immiscible fluids and the case of a single fluid. F. Hamza, A. M. Abd El-Latief, and W. Khatan Copyright © 2015 F. Hamza et al. All rights reserved. Inclusion of CFRP-Epoxy Composite for End Anchorage in NSM-Epoxy Strengthened Beams Sun, 10 May 2015 06:40:12 +0000 Nowadays, the use of near surface mounted (NSM) technique strengthening reinforced concrete (RC) structural members is going very popular. The failure modes of NSM strengthened reinforced concrete (RC) beams have been shown to be largely due to premature failure such as concrete cover separation. In this study, CFRP U-wrap end anchorage with CFRP fabrics was used to eliminate the concrete cover separation failure. A total of eight RC rectangular beam specimens of 125 mm width, 250 mm depth, and 2300 mm length were tested. One specimen was kept unstrengthened as a reference; three specimens were strengthened with NSM steel bars and the remaining four specimens were strengthened with NSM steel bars together with the U-wrap end anchorage. The experimental results showed that wrapped strengthened beams had higher flexural strength and superior ductility performance. The results also show that these beams had less deflection, strain, crack width, and spacing. Md. Akter Hosen, Mohd Zamin Jumaat, and A. B. M. Saiful Islam Copyright © 2015 Md. Akter Hosen et al. All rights reserved. Modeling of Stacking Fault Energy in Hexagonal-Close-Packed Metals Thu, 07 May 2015 09:19:17 +0000 The deformation of metals is known to be largely affected by their stacking fault energies (SFEs). In the review, we examine the theoretical background of three normally used models, supercell model, Ising model, and bond orientation model, for the calculation of SFE of hexagonal-close-packed (hcp) metals and their alloys. To predict the nature of slip in nanocrystalline metals, we further review the generalized stacking fault (GSF) energy curves in hcp metals and alloys. We conclude by discussing the outstanding challenges in the modeling of SFE and GSF energy for studying the mechanical properties of metals. Zhigang Ding, Shuang Li, Wei Liu, and Yonghao Zhao Copyright © 2015 Zhigang Ding et al. All rights reserved. Injection Performance of a Gas-Solid Injector Based on the Particle Trajectory Model Wed, 06 May 2015 06:33:41 +0000 Gas-solid injectors are widely used feeding equipment in pneumatic conveying systems. The performance of a gas-solid injector has a significant influence on the type of application it can be employed for. To determine the key factors influencing the injection performance and address clogging problems in a gas-solid injector during a pneumatic conveying process, the particle trajectory model has been utilised as a means to perform simulations. In the particle trajectory model, the gas phase is treated as a continuous medium and the particle phase is treated as a dispersed phase. In this work, numerical and experimental studies were conducted for different nozzle positions in a gas-solid injector. A gas-solid injector test-bed was constructed based on the results of the simulations. The results show that the nozzle position is the key factor that affects the injection performance. The number of extrusive particles first increases and then decreases with the change in the nozzle position from left to right. Additionally, there is an optimum nozzle position that maximises the injection mass and minimises the number of particles remaining in the hopper. Based on the results of this work, the injection performance can be significantly increased and the clogging issues are effectively eliminated. Daolong Yang, Jianping Li, Changlong Du, Hongxiang Jiang, and Kehong Zheng Copyright © 2015 Daolong Yang et al. All rights reserved. A Study of Thin Film Resistors Prepared Using Ni-Cr-Si-Al-Ta High Entropy Alloy Mon, 04 May 2015 14:29:33 +0000 Ni-Cr-Si-Al-Ta resistive thin films were prepared on glass and Al2O3 substrates by DC magnetron cosputtering from targets of Ni0.35-Cr0.25-Si0.2-Al0.2 casting alloy and Ta metal. Electrical properties and microstructures of Ni-Cr-Si-Al-Ta films under different sputtering powers and annealing temperatures were investigated. The phase evolution, microstructure, and composition of Ni-Cr-Si-Al-Ta films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Auger electron spectroscopy (AES). When the annealing temperature was set to 300°C, the Ni-Cr-Si-Al-Ta films with an amorphous structure were observed. When the annealing temperature was at 500°C, the Ni-Cr-Si-Al-Ta films crystallized into Al0.9Ni4.22, Cr2Ta, and Ta5Si3 phases. The Ni-Cr-Si-Al-Ta films deposited at 100 W and annealed at 300°C which exhibited the higher resistivity 2215 -cm with −10 ppm/°C of temperature coefficient of resistance (TCR). Ruei-Cheng Lin, Tai-Kuang Lee, Der-Ho Wu, and Ying-Chieh Lee Copyright © 2015 Ruei-Cheng Lin et al. All rights reserved. Fabrication of Fe-6.5wt%Si Ribbons by Melt Spinning Method on Large Scale Mon, 04 May 2015 13:14:48 +0000 Melt spinning method has been widely applied for fabrication of Fe-based amorphous/nanocrystalline ribbons in industry. Compared with Fe-based amorphous/nanocrystalline alloys, Fe-6.5wt%Si high silicon steel is of low cost and has comparable excellent soft magnetic properties. Due to higher melting point and absence of supercooled liquid region, fabrication of Fe-6.5wt%Si ribbons is very hard and is only on lab scale. In this paper, we report that large scale fabrication of Fe-6.5wt%Si ribbons was successful and microstructures, ordered structures, and mechanical and soft magnetic properties of the ribbons were investigated. Due to rapid solidification rate, the ribbons were of ultrafine grains, and low degree of order and exhibited some extent of bending and tensile ductility. After heat treatment, excellent soft magnetic properties were obtained. Due to near-zero magnetostriction, the ribbons are promising to be used in electric devices with high frequencies where low noises are required. Y. F. Liang, S. Wang, H. Li, Y. M. Jiang, F. Ye, and J. P. Lin Copyright © 2015 Y. F. Liang et al. All rights reserved. The Microstructures and Electrical Resistivity of (Al, Cr, Ti)FeCoNiOx High-Entropy Alloy Oxide Thin Films Mon, 04 May 2015 12:42:37 +0000 The (Al, Cr, Ti)FeCoNi alloy thin films were deposited by PVD and using the equimolar targets with same compositions from the concept of high-entropy alloys. The thin films became metal oxide films after annealing at vacuum furnace for a period; and the resistivity of these thin films decreased sharply. After optimum annealing treatment, the lowest resistivity of the FeCoNiOx, CrFeCoNiOx, AlFeCoNiOx, and TiFeCoNiOx films was 22, 42, 18, and 35 μ-cm, respectively. This value is close to that of most of the metallic alloys. This phenomenon was caused by delaminating of the alloy oxide thin films because the oxidation was from the surfaces of the thin films. The low resistivity of these oxide films was contributed to the nonfully oxidized elements in the bottom layers and also vanishing of the defects during annealing. Chun-Huei Tsau, Zhang-Yan Hwang, and Swe-Kai Chen Copyright © 2015 Chun-Huei Tsau et al. All rights reserved. Effects of Static Magnetic Fields on the Physical, Mechanical, and Microstructural Properties of Cement Pastes Mon, 04 May 2015 07:50:43 +0000 This paper presents the results of an experimental study carried out to comprehend the physical, mechanical, and microstructural behavior of cement pastes subjected to static magnetic fields while hydrating and setting. The experimental methodology consisted in exposing fresh cement pastes to static magnetic fields at three different magnetic induction strengths: 19.07, 22.22, and 25.37 Gauss. The microstructural characterization makes evident that there are differences in relation to amount and morphology of CSH gel; the amount of CSH is larger and its morphology becomes denser and less porous with higher magnetostatic induction strengths; it also shows the evidence of changes in the mineralogical composition of the hydrated cement pastes. The temperature increasing has no negative effects over the cement paste compressive strength since the magnetostatic field affects the process of hydration through a molecular restructuring process, which makes cement pastes improve microstructurally, with a reduced porosity and a higher mechanical strength. Juan J. Soto-Bernal, Rosario Gonzalez-Mota, Iliana Rosales-Candelas, and Jose A. Ortiz-Lozano Copyright © 2015 Juan J. Soto-Bernal et al. All rights reserved. Frictional Performance and Temperature Rise of a Mining Nonasbestos Brake Material during Emergency Braking Thu, 30 Apr 2015 17:24:51 +0000 By simulating emergency braking conditions of mine hoisters, tribological experiments of a mining nonasbestos brake material sliding on E355CC steel friction disc investigated a pad-on-disc friction tester. It is shown that, under combined influence of braking velocity and pressure, the lubricating film and micro-convex-apices on wear surface would have complex physicochemical reactions which make the instant friction coefficient rise gradually while the instant surface temperature rises first and then falls. With the antifriction effect from lubricating film and the desquamating of composite materials, the mean friction coefficient decreases first, then rises, and decreases again with the increasing of initial braking velocity. And with the existence of micro-convex-apices and variation from increment ratio of load and actual contacting area, it rises first and then falls with the increasing of braking pressure. However, the mean surface temperature rises obviously with the increasing of both initial braking velocity and braking pressure for growth of transformed kinetic energy. It is considered that the friction coefficient cannot be considered as a constant when designing brake devices for mine hoisters. And special attention should be paid to the serious influence of surface temperature on tribological performance of brake material during emergency braking. Jiusheng Bao, Zengsong Li, Dongyang Hu, Yan Yin, and Tonggang Liu Copyright © 2015 Jiusheng Bao et al. All rights reserved. Experimental and Numerical Method for the Analysis of Warm Titanium Sheet Stamping of an Automotive Component Wed, 29 Apr 2015 15:22:54 +0000 Product design involves many aspects as geometry and material or mechanical requirements that have to be chosen on the base of the part requirements. Manufacturing process is the link between them representing a fundamental aspect of the product design process. Designers and technicians have a consolidated set of tools and knowledge based on long time experience, but the request of more new performing products characterized by more complex geometries or harder to form materials as Titanium alloys stimulated the use of numerical models. They allow us to study the product feasibility but they require reliable inputs for their development and validation. The present research focuses on sheet stamping processes and proposes a methodology that uses the Nakazima test to characterize the formability of the material and to develop and validate the model. In particular, the method is applied to cold (20°C) and warm (300°C) stamping of a complex automotive component made of CP Titanium. After characterizing the material and validating the model at the different temperatures, the stamping process is studied and results are compared. In particular, this approach allowed joining the experimental tests required to develop and validate the model, therefore reducing the resources required for the product design. Antonio Fiorentino, Elisabetta Ceretti, and Claudio Giardini Copyright © 2015 Antonio Fiorentino et al. All rights reserved. The Effects of Natural Weathering on Color Stability of Impregnated and Varnished Wood Materials Tue, 28 Apr 2015 12:54:31 +0000 The aim of this study was to investigate effects of natural weathering on color stability of Scots pine (Pinus sylvestris L.) and Oriental beech (Fagus orientalis L.) impregnated with some chemicals [tanalith-E (TN-E), adolit-KD5 (AD-KD5), and chromated copper arsenate (CCA)] and then varnished [synthetic varnish (SV) and polyurethane varnish (PV)]. While applying varnish increased lightness, impregnation decreased lightness of the wood specimens before natural weathering. Natural weathering caused greenish, bluish, and dark color tones of the wood surface. Total color change was increased with increasing exposure times in natural weathering. Untreated (control) wood specimens exhibited higher color changes than the other wood specimens in all the stages of natural weathering. The total color changes of untreated Oriental beech specimens were less than untreated Scots pine specimens. The color stability of impregnated and varnished wood specimens gave better results than untreated and solely varnished wood specimens after natural weathering. The best color stability was obtained from both Oriental beech and Scots pine wood impregnated with TN-E before PV coating. Turkay Turkoglu, Ergun Baysal, and Hilmi Toker Copyright © 2015 Turkay Turkoglu et al. All rights reserved. Evaluation of Service Life of Polystyrene in Tropical Marine Environment by Principal Component Analysis Mon, 27 Apr 2015 13:51:06 +0000 To predict the service life of polystyrene (PS) under an aggressive environment, the nondimensional expression Z was established from a data set of multiple properties of PS by principal component analysis (PCA). In this study, PS specimens were exposed to the tropical environment on Xisha Islands in China for two years. Chromatic aberration, gloss, tensile strength, elongation at break, flexural strength, and impact strength were tested to evaluate the aging behavior of PS. Based on different needs of industries, each of the multiple properties could be used to evaluate the service life of PS. However, selecting a single performance variation will inevitably hide some information about the entire aging process. Therefore, finding a comprehensive measure representing the overall aging performance of PS can be highly significant. Herein, PCA was applied to obtain a specific property (Z) which can represent all properties of PS. Z of PS degradation showed a slight decrease for the initial two months of exposure after which it increased rapidly in the next eight months. Subsequently, a slower increase of Z value was observed. From the three different stages shown as Z value increases, three stages have been identified for PS service life. Dongdong Song, Jin Gao, Lin Lu, and Xiaogang Li Copyright © 2015 Dongdong Song et al. All rights reserved. A Novel Composite Material Designed from FeSi Powder and Mn0.8Zn0.2Fe2O4 Ferrite Mon, 27 Apr 2015 13:22:02 +0000 A design of the novel microcomposite material composed of spherical FeSi particles and Mn0.8Zn0.2Fe2O4 ferrite is reported together with a characterization of basic mechanical and electrical properties. The sol-gel autocombustion method was used for a preparation of Mn0.8Zn0.2Fe2O4 ferrite, which has a spinel-type crystal structure as verified by XRD and TEM analysis. The final microcomposite samples were prepared by a combination of the traditional PM compaction technique supplemented with unconventional microwave sintering process of the prepared green compacts. The composition and distribution of the secondary phase formed by the spinel ferrite were examined by SEM. It is demonstrated that the prepared composite material has a tight arrangement without any significant porosity, which manifests itself through superior mechanical properties (high mechanical hardness, Young modulus, and transverse rupture strength) and specific electric resistivity compared to the related composite materials including resin as the organic binder. Magdalena Streckova, Radovan Bures, Maria Faberova, Pavel Kurek, Pavla Roupcova, Hynek Hadraba, Vladimir Girman, and Jozef Strecka Copyright © 2015 Magdalena Streckova et al. All rights reserved. Torsion Dependence of Domain Transition and MI Effect of Melt-Extracted Co68.15Fe4.35Si12.25B13.25Nb1Cu1 Microwires Mon, 27 Apr 2015 13:15:53 +0000 We present the torsional stress induced magnetoimpedance (MI) effect and surface domain structure evolution of magnetostrictive melt-extracted Co68.15Fe4.35Si12.25B13.25Nb1Cu1 microwires. Experimental results indicate that the surface domain structures observed by magnetic force microscope (MFM) transform from the weak circumferential domain of as-cast state to the helical domain under large torsional strain of 81.6 (2π rad/m). Domain wall movement distorts at torsional strain (2π rad/m) and forms a helical anisotropy with an angle of around 30° versus axial direction of wire. At 15 MHz, the maximum of GMI ratio (%) increases to 194.4% at (2π rad/m) from 116.3% of the as-cast state and then decreases to 134.9% at (2π rad/m). The torsion magnetoimpedance (TMI) ratio (%) is up to 290%. Based on this large torsional strain and high MI ratio, the microwire can be as an referred candidate for high-performance TMI sensor application. Dawei Xing, Dongming Chen, Fang Liu, Jingshun Liu, Hongxian Shen, Zhiliang Ning, Fuyang Cao, and Jianfei Sun Copyright © 2015 Dawei Xing et al. All rights reserved. The Effect of Stoichiometry on Hydrogen Embrittlement of Ordered Ni3Fe Intermetallics Mon, 27 Apr 2015 11:56:38 +0000 The effects of Fe stoichiometry on hydrogen embrittlement and hydrogen diffusion in ordered Ni3Fe intermetallics were investigated. The experimental results show that the ordered Ni3Fe alloy with the normal stoichiometry has the lowest mechanical property, the highest susceptibility to hydrogen, and the highest ability of catalytic reaction. The mechanical properties, the susceptibility to hydrogen embrittlement, and the amount of adsorbed hydrogen of the ordered Ni3Fe alloy are dependent of degree of order of the alloy. The apparent hydrogen diffusion coefficient of the ordered Ni3Fe alloy is independent on degree of order of the alloy but depends on Fe stoichiometry. The activation energy of hydrogen diffusion decreased linearly with Fe stoichiometry for the ordered Ni3Fe alloy. Y. X. Chen, Tao Chen, and Haiyan Qian Copyright © 2015 Y. X. Chen et al. All rights reserved. Parallel Piezoelectric Shunt Damping of Rotationally Periodic Structures Mon, 27 Apr 2015 07:38:24 +0000 This paper considers the RL shunt damping of rotationally periodic structures with an array of regularly spaced piezoelectric patches. The technique is targeted to the damping of a specific mode with nodal diameters. For this particular case, one can take advantage of the shape of the targeted mode to organize the piezoelectric patches as a modal filter (in parallel loops) which reduces the demand on the inductors of the tuned inductive shunt. In the case of a perfectly rotationally periodic structure, it is possible to organize 4 piezoelectric transducers (PZT patches) in two parallel loops of 2 patches each. In this way, the demand on the inductors is reduced by as compared to independent loops, which may allow a fully passive integration of the RL shunt in a turbomachinery application. The method is first illustrated experimentally on a circular plate; it is then applied to a prototype of an industrial bladed drum. The influence of blade mistuning is investigated. Bilal Mokrani, Renaud Bastaits, Mihaita Horodinca, Iulian Romanescu, Ioanica Burda, Régis Viguié, and André Preumont Copyright © 2015 Bilal Mokrani et al. All rights reserved. Effect of the Aggressive Environment on the Damage of a Glass Polyester Composite Developed by Hand Layup Process Mon, 27 Apr 2015 07:08:51 +0000 This work treats the behavior of a glass fibre/unsaturated polyester (UP) composite with structural defects subjected to the attack of two corrosive solutions: H2SO4 and NaOH. The gravimetric analysis, the uptake mass of the resin, and the interfaces in the composite are established according to the proportion of the matrix/composite. The obtained results showed that, in the acidic solution, the glass fibre and the fibre/matrix interface absorption share is more significant than the alkaline solution. While the Fourier transform infrared analysis (FT-IR) of the UP resin revealed the presence of chemical degradation phenomenon (hydrolysis), the fibre corrosion was characterized by the atomic absorption analysis (AAS). The fibres/matrix interfaces degradation was confirmed by microscopic observations (SEM). The diffusion kinetics of the both acid and alkaline solutions and chemical and mechanical degradation are affected by the presence of the pores in elaborated material. Nabila Belloul, Hassiba Hamadache, Ali Ahmed Benyahia, and Aîcha Serier Copyright © 2015 Nabila Belloul et al. All rights reserved. Resistive Switching Characteristics in TiO2/LaAlO3 Heterostructures Sandwiched in Pt Electrodes Thu, 23 Apr 2015 08:42:46 +0000 TiO2/LaAlO3 (TiO2/LAO) heterostructures have been deposited on Pt/TiO2/SiO2/Si substrates by pulsed laser deposition. Resistive switching characteristics of Pt/TiO2/LAO/Pt have been studied and discussed in comparison with those of Pt/TiO2/Pt. It is observed that the switching uniformity and the ON/OFF resistance ratio can be greatly improved by introducing the LAO layer. The observed resistive switching characteristics are discussed as a function of LAO thickness and explained by the preferential formation and rupture of conductive filaments, composed of oxygen vacancies, in the LAO layer. Yuyuan Cao, Qitao Di, Lin Zhu, Aidong Li, and Di Wu Copyright © 2015 Yuyuan Cao et al. All rights reserved. Water Vapor Sensors Based on the Swelling of Relief Gelatin Gratings Sun, 19 Apr 2015 10:59:46 +0000 We report on a novel device to measure relative humidity. The sensor is based on surface diffraction gratings made of gelatin. This material swells and shrinks according to the content of water vapor in air. By sending a light beam to the grating, diffracted orders appear. Due to the gelatin swelling or shrinking, first order intensity changes according to the relative humidity. Calibration curves relating intensity versus relative humidity have been found. The fabrication process of diffraction gratings and the testing of the prototype sensing devices are described. Sergio Calixto and Miguel V. Andres Copyright © 2015 Sergio Calixto and Miguel V. Andres. All rights reserved. Effect of the Electrolyte Temperature and the Current Density on a Layer Microhardness Generated by the Anodic Aluminium Oxidation Sun, 19 Apr 2015 09:27:16 +0000 The paper investigates the influence of the chemical composition and temperature of electrolyte, the oxidation time, voltage, and the current density on Vickers microhardness of aluminium oxide layers, at the same time. The layers were generated in the electrolytes with different concentrations of sulphuric and oxalic acids and surface current densities 1 A·dm−2, 3 A·dm−2, and 5 A·dm−2. The electrolyte temperature varied from −1.78°C to 45.78°C. The results have showed that while increasing the electrolyte temperature at the current density of 1 A·dm−2, the increase in the layer microhardness values is approximately by 66%. While simultaneously increasing the molar concentration of H2SO4 in the electrolyte, the growth rate of the microhardness value decreases. At the current density of 3 A·dm−2, by increasing the electrolyte temperature, a reduction in the microhardness of the generated layer occurs with the anodic oxidation time less than 25 min. The electrolyte temperature is not significant with the changing values of the layer microhardness at voltages less than 10.5 V. Emil Spišák, Miroslav Gombár, Ján Kmec, Alena Vagaská, Erika Fechová, Peter Michal, Ján Piteľ, and Daniel Kučerka Copyright © 2015 Emil Spišák et al. All rights reserved.