Advances in Materials Science and Engineering http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Visualization Experiment on Electrorheological Fluid in Dynamic Coupling Field Thu, 26 May 2016 15:13:45 +0000 http://www.hindawi.com/journals/amse/2016/5108401/ Due to lack of visualization experiment on the mechanism of electrorheological effect in dynamic field, a visualization experimental system is designed and successfully made. Through this experiment, the submicroscopic dynamic structural changes of electrorheological (ER) fluids in the coupling field composed by external electric field and flow field are observed. The experimental results indicate that the rheological behaviors of ER fluids are mainly influenced by the polarization forces and the hydrodynamic forces in the dynamic coupling field. And the experiment shows that the yield fracture of chain structures determined the yield strength of ER fluids firstly occurring near the plate electrodes, which expresses the microflow characteristic of velocity slip. Meanwhile, the capture effect has been verified in this experiment. Shisha Zhu, Qi Luo, Jingang Liu, and Toyohisa Fujita Copyright © 2016 Shisha Zhu et al. All rights reserved. Study of the Mechanical Properties of a Nanostructured Surface Layer on 316L Stainless Steel Thu, 26 May 2016 12:05:32 +0000 http://www.hindawi.com/journals/amse/2016/7517616/ A nanostructured surface layer (NSSL) was generated on a 316L stainless steel plate through surface nanocrystallization (SNC). The grains of the surface layer were refined to nanoscale after SNC treatment. Moreover, the microstructure and mechanical properties of NSSL were analyzed with a transmission electron microscope (TEM) and scanning electron microscope (SEM), through nanoindentation, and through reverse analysis of finite element method (FEM). TEM results showed that the grains in the NSSL measured 8 nm. In addition, these nanocrystalline grains took the form of random crystallographic orientation and were roughly equiaxed in shape. In situ SEM observations of the tensile process confirmed that the motions of the dislocations were determined from within the material and that the motions were blocked by the NSSL, thus improving overall yielding stress. Meanwhile, the nanohardness and the elastic modulus of the NSSL, as well as those of the matrix, were obtained with nanoindentation technology. The reverse analysis of FEM was conducted with MARC software, and the process of nanoindentation on the NSSL and the matrix was simulated. The plastic mechanical properties of NSSL can be derived from the simulation by comparing the results of the simulation and of actual nanoindentation. F. C. Lang, Y. M. Xing, J. Zhu, and Y. R. Zhao Copyright © 2016 F. C. Lang et al. All rights reserved. The Influence of Salt Solution on Morphological Changes in a Geosynthetic Clay Liner Thu, 26 May 2016 08:32:28 +0000 http://www.hindawi.com/journals/amse/2016/6349407/ Morphological variations of geosynthetic clay liner (GCL) samples, hydrated with two different permeates, distilled water and NaCl solution (100 mM concentration), were observed in detail using microscopic analysis. After the GCL samples were hydrated with the NaCl solution, they were observed with an optical microscope. While the surface of the treated GCL samples was similar to the surface of the untreated GCL, a crystal deposit was found on the surface of the treated samples. Using a scanning electron microscope (SEM), a more solid appearance was observed for the bentonite particles contained in the GCL after the sample was hydrated with distilled water in comparison to the GCL sample that was hydrated with the NaCl solution. It appears that salt solution hydration results in less swelling of the bentonite particles. Furthermore, the energy-dispersive X-ray spectrometer (EDS) results showed that distilled water hydration had no effect on the distribution of the elements contained in the GCL samples. However, bound chlorine was observed, which demonstrated that the bentonite particles had absorbed the NaCl solution. In addition, changes in the hydraulic conductivity of the hydrated GCL samples were also observed. Mochamad Arief Budihardjo Copyright © 2016 Mochamad Arief Budihardjo. All rights reserved. Effect of Particle Size on the Wear Property of Magnetorheological Fluid Thu, 26 May 2016 08:17:04 +0000 http://www.hindawi.com/journals/amse/2016/4740986/ Aiming to study the effect of particle size on the wear property of magnetorheological fluid (MRF), experiment materials, preparation process, and test methods are elaborated, and three different MRF samples consisting of particles of different size are prepared. Test experiments are carried out and the effect of particle size on the wear property of MRF is discussed. Moreover, the microstructures of particles extracted from MRF obtained before and after the wear experiments are observed by scanning electron microscope (SEM). Experimental results show that the particle size has a significant effect on wear property of MRF. Furthermore, the MRF with particles of 1.5–2.8 μm diameter on average is good for the requirement of engineering applications. Qiuxiang Zhang, Xinhua Liu, Yankun Ren, Lifeng Wang, and Yuan Hu Copyright © 2016 Qiuxiang Zhang et al. All rights reserved. Flexural and Thermal Properties of Novel Energy Conservation Slotted Reinforced Concrete Beams Thu, 26 May 2016 07:30:00 +0000 http://www.hindawi.com/journals/amse/2016/4642810/ Conventional solid reinforced concrete (RC) beams were modified to slotted beams for consideration as thermal insulation structural components. The slotted beam consisted of an outer and an inner beam, respectively, with a slot located near the middle of the beam along its width direction for filling thermal insulation material. Flexural and thermal behavior of the slotted beams were investigated. Three RC reference solid beams and six slotted beams were fabricated and tested under four-point bending tests. The test results indicated that the failure mode of both slotted beams and the solid beams was flexural failure. However, the damage process of the slotted beams was different from that of the solid beams at the final loading stage. The moment curvature analysis indicated that the tensile reinforcement ratio of the outer and inner beams had an important effect on the flexural behavior, especially the ductility of the slotted beams. Thermal study indicated that the heat transfer coefficient of the slotted beam was greatly reduced and the thermal inertia factor increased a lot, compared with the solid beam. In addition, FE simulation results showed that a new frame structure using slotted beams exhibited obvious and attractive thermal insulation property. Gao Ma, Liang Huang, Libo Yan, Hui Wang, and Peng Yin Copyright © 2016 Gao Ma et al. All rights reserved. Correction of Earth Pressure and Analysis of Deformation for Double-Row Piles in Foundation Excavation in Changchun of China Thu, 26 May 2016 07:14:36 +0000 http://www.hindawi.com/journals/amse/2016/9818160/ In order to study the earth pressure and the deformation behavior of the double-row piles in foundation excavation, a large-scale physical model test was introduced to simulate deformation of double-row piles in foundation excavation based on the principle of similarity theory in this paper. Represented by the deep foundation pit engineering of Changchun, the strain and the displacement of the double-row piles and the earth pressure are calculated by the above-mentioned physical model test. Then a numerical simulation has been carried out to validate practicability of the physical model test. The results show that the strain and the displacement of the front-row piles are larger than the back-row piles. The earth pressure of the front-row piles appears to be “right convex,” correcting the specification of the earth pressure and putting forward the coefficient of β. The results in this paper may provide constructive reference for practical engineering. Yijun Zhou, Aijun Yao, Haobo Li, and Xuan Zheng Copyright © 2016 Yijun Zhou et al. All rights reserved. Effects of La and Ce Addition on the Modification of Al-Si Based Alloys Wed, 25 May 2016 13:27:14 +0000 http://www.hindawi.com/journals/amse/2016/5027243/ This study focuses on the effects of the addition of rare earth metals (mainly lanthanum and cerium) on the eutectic Si characteristics in Al-Si based alloys. Based on the solidification curves and microstructural examination of the corresponding alloys, it was found that addition of La or Ce increases the alloy melting temperature and the Al-Si eutectic temperature, with an Al-Si recalescence of 2-3°C, and the appearance of post-α-Al peaks attributed to precipitation of rare earth intermetallics. Addition of La or Ce to Al-(7–13)% Si causes only partial modification of the eutectic Si particles. Lanthanum has a high affinity to react with Sr, which weakens the modification efficiency of the latter. Cerium, however, has a high affinity for Ti, forming a large amount of sludge. Due to the large difference in the length of the eutectic Si particles in the same sample, the normal use of standard deviation in this case is meaningless. Emad M. Elgallad, Herbert W. Doty, Saleh A. Alkahtani, and Fawzy H. Samuel Copyright © 2016 Emad M. Elgallad et al. All rights reserved. Effect of Chlorides on Conductivity and Dielectric Constant in Hardened Cement Mortar: NDT for Durability Evaluation Tue, 24 May 2016 09:28:12 +0000 http://www.hindawi.com/journals/amse/2016/6018476/ Dielectric constant and conductivity, the so-called EM properties (electromagnetic), are widely adopted for NDT (Nondestructive Technique) in order to detect damage or evaluate performance of concrete without damage to existing RC (reinforced concrete). Among deteriorating agents, chloride ion is considered as one of the most critical threats due to rapid penetration and direct effect on steel corrosion. In the work, cement mortar samples with 3 w/c (water-to-cement) ratios and 4 levels of chloride addition are considered. Conductivity and dielectric constant are measured in the normal frequency range. They increase with strength of mortar and more chloride ions due to denser pore formation. Furthermore, the behaviors of measured EM property are investigated with carbonation velocity and strength, which shows an attempt of application to durability evaluation through EM measurement. Sunkook Kim, Joowon Kang, Sang-Hyo Lee, and Yong Han Ahn Copyright © 2016 Sunkook Kim et al. All rights reserved. Evaluation of Subsurface Damage in Concrete Deck Joints Using Impact Echo Method Mon, 23 May 2016 09:51:36 +0000 http://www.hindawi.com/journals/amse/2016/8230398/ Many factors can affect the overall performance and longevity of highway bridges, including the integrity of their deck joints. This study focuses on the evaluation of subsurface damage in deteriorated concrete deck joints, which includes the delamination and corrosion of the reinforcement. Impact echo and surface wave technology, mainly a portable seismic property analyzer (PSPA), were employed to evaluate the structural deficiency of concrete joints. Laboratory tests of core samples were conducted to verify the nondestructive test results. The primary advantage of the PSPA as a bridge assessment tool lies in its ability to assess the concrete’s modulus and to detect subsurface defects at a particular point simultaneously. Larry Rickard and Wonchang Choi Copyright © 2016 Larry Rickard and Wonchang Choi. All rights reserved. Experimental Research on Hysteretic Characteristics of Steel Plates Artificially Corroded by Neutral Salt Spray Mon, 23 May 2016 07:41:36 +0000 http://www.hindawi.com/journals/amse/2016/7645763/ This paper aims to study the hysteretic characteristics of the steel plates artificially corroded by neutral salt spray. Salt spray was applied to accelerate the corrosion on the steel plates; specimens of varying degrees of corrosion were obtained in this manner. And each specimen was subject to cyclic loading test to get the hysteretic curve. Then the experimental results were extensively discussed, focusing on strength and ductility, hysteretic energy, the skeleton curve, and unloading and loading curve. After that, the hysteretic constitutive model of corroded steel was established based on the first time loading criterion, unloading criterion, cycle skeleton criterion, and reloading curve criterion. The result of the experiment showed that, with the increase of the degree of corrosion, the mechanical properties and seismic energy dissipation performance of seismic energy of the steel decreased; the deterioration of ductility got aggravated. On the other hand, the skeleton curve and the Ramberg-Osgood model were well matched, and the coefficient of circular enhancement showed a decreasing trend; the variation of cyclic hardening exponent did not have an obvious pattern. Meanwhile, the hysteretic constitutive model of corroded steel and the results of the experiment were well matched. Shan-hua Xu, Guang-chong Qin, and Zong-xing Zhang Copyright © 2016 Shan-hua Xu et al. All rights reserved. Angular Dependence of Spin Transfer Switching in Spin Valve Nanopillar Based Heusler Alloy Sun, 22 May 2016 14:26:34 +0000 http://www.hindawi.com/journals/amse/2016/2826795/ The spin transfer induced magnetization switching in current perpendicular-to-the-plane spin valve nanopillar based Co2FeAl0.5Si0.5 Heusler alloy with varying the initial angles of the magnetization of sensing layer, , was investigated via macrospin simulations. The effects of an in-plane magnetic field, , on the switching behavior were also evaluated. The magnetization switching was excited by spin polarized switching current, . The time varying magnetization was computed by the Landau-Lifshitz-Gilbert-Slonczewski equation, while the spin transfer induced noise was examined by using the power spectral density analysis. It was found that should be narrowly initialized since this configuration produces the small noise during the switching. Also, the negative produced more uniform switching than the positive due to existence of ferromagnetic exchange coupling. When was presented, the noise generated at low frequencies could be suppressed, and then the switching behavior became more uniform. In addition, the results indicated that the noise configuration could be explained by the physical dynamic of magnetization behavior. Hence, the spin transfer induced noise needs to be minimized in order to improve the performance of spin transfer torque random access memory for high density recording. Pirat Khunkitti, Anan Kruesubthaworn, Arkom Kaewrawang, Tim Mewes, Claudia K. A. Mewes, and Apirat Siritaratiwat Copyright © 2016 Pirat Khunkitti et al. All rights reserved. Experimental Research on High Temperature Resistance of Modified Lightweight Concrete after Exposure to Elevated Temperatures Sun, 22 May 2016 13:05:38 +0000 http://www.hindawi.com/journals/amse/2016/5972570/ In order to improve the spalling resistance of lightweight aggregate concrete at high temperature, two types of modified materials were used to modify clay ceramsite lightweight aggregates by adopting the surface coating modification method. Spalling of the concrete specimens manufactured by using the modified aggregates was observed during a temperature elevation. Mass loss and residual axial compressive strength of the modified concrete specimens after exposure to elevated temperatures were also tested. Concrete specimens consisting of ordinary clay ceramsites and crushed limestone were manufactured as references for comparison. The results showed that the ordinary lightweight concrete specimens and the crushed limestone concrete specimens were completely spalled after exposure to target temperatures above 400°C and 1000°C, respectively, whereas the modified concrete specimens remained intact at 1200°C, at which approximately 25% to 38% of the residual compressive strength was retained. The results indicated that the modified lightweight concrete specimens have exhibited superior mechanical properties and resistance to thermal spalling after exposure to elevated temperatures. Ke-cheng He, Rong-xin Guo, Qian-min Ma, Feng Yan, Zhi-wei Lin, and Yan-Lin Sun Copyright © 2016 Ke-cheng He et al. All rights reserved. Topographical and Physicochemical Contrast in Photopatterned SU-8 Films for Microfabrication of Multilayer Structures Sun, 22 May 2016 12:47:04 +0000 http://www.hindawi.com/journals/amse/2016/5278102/ During SU-8 standard photolithography process, a patterned topography is formed with a characteristic height profile produced by the different shrinkage of the UV exposed and masked regions. We study the change of wettability, film solubility, and topographic modifications on SU-8 films of different thicknesses and show its relevance in the formation of spinning-flow arrays on top layers made from positive photoresists. Also, considerable contrast in film solubility and surface energy as observed from contact angle measurements is produced. Interface diffusion of the photoresists was also observed and followed by Rutherford Back Scattering. We discuss the derivations of the mentioned effects concerning the limitations to multilayered microfabrication processes and possibilities to take advantage of the surface profiles obtained. L. Salazar Alarcón, E. D. Martínez, L. M. Rodríguez, and H. Pastoriza Copyright © 2016 L. Salazar Alarcón et al. All rights reserved. Electrical Response of CdS Thin Film and CdS/Si Heterojunction to Gamma Radiation Thu, 19 May 2016 16:28:26 +0000 http://www.hindawi.com/journals/amse/2016/3183909/ Gamma irradiation method has been used to change the electrical properties of CdS thin film. A specific dose of γ-irradiation increases the activation energy of CdS thin film. In addition, γ-irradiation was used to change the sign of Hall coefficient, , of CdS thin film from negative to positive irrespective of temperature. The Hall mobility mechanism shows noticeable change after γ-irradiation from decreasing to increasing with raising the temperature. In depth, analysis was done using capacitance-voltage measurement in order to realize the modification in the CdS/Si junction band gap after γ-irradiation. Several parameters were also studied such as charge carrier concentration, , and flat band potential, . The γ-irradiation was found to increase the concentration of the deep traps within the band gap of the CdS/Si heterojunction. M. R. Balboul, A. Abdel-Galil, I. S. Yahia, and A. Sharaf Copyright © 2016 M. R. Balboul et al. All rights reserved. Structure, Mechanism, and Application of Vacuum Insulation Panels in Chinese Buildings Thu, 19 May 2016 09:07:01 +0000 http://www.hindawi.com/journals/amse/2016/1358072/ Thermal insulation is one of the most used approaches to reduce energy consumption in buildings. Vacuum insulation panels (VIPs) are new thermal insulation materials that have been used in the domestic and overseas market in the last 20 years. Due to the vacuum thermal insulation technology of these new materials, their thermal conductivity can be as low as 0.004 W/(m·K) at the center of panels. In addition, VIPs that are composites with inorganic core and an envelope out of commonly three metallized PET layers and a PE sealing layer can provide B class fire resistance (their core materials are not flammable and are classified as A1). Compared with other conventional thermal insulation materials, the thermal insulation and fire resistance performances form the foundation of VIP’s applications in the construction industry. The structure and thermal insulation mechanism of VIP and their application potential and problems in Chinese buildings are described in detail. Changhai Peng and Jianqiang Yang Copyright © 2016 Changhai Peng and Jianqiang Yang. All rights reserved. Effect of Variable Properties and Moving Heat Source on Magnetothermoelastic Problem under Fractional Order Thermoelasticity Wed, 18 May 2016 11:51:06 +0000 http://www.hindawi.com/journals/amse/2016/5341569/ A one-dimensional generalized magnetothermoelastic problem of a thermoelastic rod with finite length is investigated in the context of the fractional order thermoelasticity. The rod with variable properties, which are temperature-dependent, is fixed at both ends and placed in an initial magnetic field, and the rod is subjected to a moving heat source along the axial direction. The governing equations of the problem in the fractional order thermoelasticity are formulated and solved by means of Laplace transform in tandem with its numerical inversion. The distributions of the nondimensional temperature, displacement, and stress in the rod are obtained and illustrated graphically. The effects of the temperature-dependent properties, the velocity of the moving heat source, the fractional order parameter, and so forth on the considered variables are concerned and discussed in detail, and the results show that they significantly influence the variations of the considered variables. Chunbao Xiong and Ying Guo Copyright © 2016 Chunbao Xiong and Ying Guo. All rights reserved. Research on the Fracture Properties and Modification Mechanism of Polyester Fiber and SBR Latex Modified Cement Concrete Wed, 18 May 2016 06:42:54 +0000 http://www.hindawi.com/journals/amse/2016/5163702/ Polyester fiber and SBR latex cement concrete is prepared as pavement surface material; its fracture properties including fracture toughness, fracture energy, CMOD, and flexural strength are studied comparing with those of normal concrete (NC), polyester fiber modified concrete (FMC), SBR polymer modified concrete (SMC), and the combination of polyester fiber and SBR polymer modified concrete (FSMC). The modification mechanism of the latex and fiber on the concrete was also studied by the methods including X-ray test, chemically combined water, heat of hydration, water loss, and scanning electron microscope. Results indicated that the concrete modified by latex and polyester fiber has flexural strength, fracture toughness, and fracture energy of 44.4%, 397.0%, and 462.8% higher than the reference normal concrete, the polymer retarded the hydration process and reduced the hydration degree of cement at early age, while the hydration degree is promoted by the polymer film for its excellent water resistance after 28 d, and the bond between the fiber and cement paste is improved by the latex. Mingkai Zhou, Dong Fang, and Deyong Jiang Copyright © 2016 Mingkai Zhou et al. All rights reserved. An Accelerated Test Method of Simultaneous Carbonation and Chloride Ion Ingress: Durability of Silica Fume Concrete in Severe Environments Tue, 17 May 2016 14:16:10 +0000 http://www.hindawi.com/journals/amse/2016/1650979/ The effects of simultaneous carbonation and chloride ion attack on mechanical characteristics and durability of concrete containing silica fume have been investigated through an accelerated test method. Specimens containing different amounts of silica fume were maintained in an apparatus in which carbon dioxide pressure and concentration and relative humidity were kept constant, and wetting and drying cycles in saline water were applied. Surface resistivity, sorptivity, CO2 consumption, and carbonation and chloride ion ingress depths measurements were taken. Phase change due to carbonation and chloride ion attack was monitored by XRD analysis, and microstructures and interfacial transition zones were studied by implementing SEM as well as mercury intrusion porosimetry. It was expected to have a synergistic effect in the tidal zone where simultaneous carbonation and chloride ion attack happen. However, the observed reduced surface resistivity, compared to specimens maintained in CO2 gas, could be due to the moisture that is available near the surface, hindering CO2 from penetrating into the pores of the specimens. Moreover, the porosity analysis of the specimens showed that the sample containing silica fume cured in the tidal zone had 50.1% less total porosity than the plain cement paste cured in the same condition. S. A. Ghahari, A. M. Ramezanianpour, A. A. Ramezanianpour, and M. Esmaeili Copyright © 2016 S. A. Ghahari et al. All rights reserved. Diffusion Decay Coefficient for Chloride Ions of Concrete Containing Mineral Admixtures Tue, 17 May 2016 06:33:54 +0000 http://www.hindawi.com/journals/amse/2016/2042918/ The diffusion coefficient for chloride ions and the diffusion decay coefficient for chloride ions are essential variables for a service life evaluation of concrete structures. They are influenced by water-binder ratio, exposure condition, curing temperature, cement type, and the type and use of mineral admixture. Mineral admixtures such as ground granulated blast furnace slag, fly ash, and silica fume have been increasingly used to improve resistance against chloride ions penetration in concrete structures built in an offshore environment. However, there is not enough measured data to identify the statistical properties of diffusion decay coefficient for chloride ions in concrete using mineral admixtures. This paper is aimed at evaluating the diffusion decay coefficient for chloride ions of concrete using ordinary Portland cement or blended cement. NT BUILD 492 method, an electrophoresis experiment, was used to measure the diffusion coefficient for chloride ions with ages. It was revealed from the test results that the diffusion decay coefficient for chloride ions was significantly influenced by W/B and the replacement ratio of mineral admixtures. Jae-Im Park, Kwang-Myong Lee, Soon-Oh Kwon, Su-Ho Bae, Sang-Hwa Jung, and Sung-Won Yoo Copyright © 2016 Jae-Im Park et al. All rights reserved. A Fractional Creep Constitutive Model for Frozen Soil in Consideration of the Strengthening and Weakening Effects Mon, 16 May 2016 12:50:11 +0000 http://www.hindawi.com/journals/amse/2016/5740292/ The triaxial creep tests of frozen silty clay mixed with sands were performed under different pressures, and the test results demonstrated that, under the low confining pressure, when the shear stress is lower than the long-term strength, the test specimen exhibits an attenuation creep because the strengthening effect is greater than the weakening effect. When the shear stress is higher than the long-term strength, the test specimen exhibits a nonattenuation creep due to the level of the strengthening and weakening effects change in different stages. As the confining pressure increases, the test specimens only exhibit an attenuation creep because of the enhancing strengthening effect. Both the hardening parameter and the damage variable were introduced to describe the strengthening and weakening effects, respectively, and a new creep constitutive model for frozen soil considering these effects was put forward based on the theory of elastoviscoplastic and the fractional derivative. Finally, the model parameters were analyzed and their determination method was also provided to reveal the trend of parameters according to the triaxial test results. The calculated results of the constitutive model show that the proposed model can describe the whole creep process of frozen soil well. Feng Hou, Quanming Li, Enlong Liu, Cheng Zhou, Mengke Liao, Huiwu Luo, and Xingyan Liu Copyright © 2016 Feng Hou et al. All rights reserved. Influence of Deposition Condition on Y2O3 Coatings Produced by Pulsed Electrophoretic Deposition Mon, 16 May 2016 12:49:30 +0000 http://www.hindawi.com/journals/amse/2016/9387651/ Y2O3 nanoparticle suspension aqueous solution was prepared using citric acid. Then, Y2O3 film was deposited using this solution with pulsed electrophoretic deposition (EPD). A dense Y2O3 film of 25.7 μm thickness was obtained with deposition conditions of 0.5 wt% Y2O3 concentration, bias voltage of 0.5 V, and bias frequency of 1 kHz. The respective resistivities of the as-deposited film and films heat-treated at 200°C and 400°C were 2.84 × 103 Ω·cm, 5.36 × 104 Ω·cm, and 2.05 × 106 Ω·cm. A 59.8 μm thick dense Y2O3 film was obtained using two-step deposition with change of the bias voltage: a first step of 0.5 V and a second step of 2.0 V. Hidetoshi Miyazaki, Asumi Ichikawa, Hisao Suzuki, and Toshitaka Ota Copyright © 2016 Hidetoshi Miyazaki et al. All rights reserved. An Experimental-Numerical Combined Method to Determine the True Constitutive Relation of Tensile Specimens after Necking Mon, 16 May 2016 06:23:28 +0000 http://www.hindawi.com/journals/amse/2016/6015752/ To obtain the material true constitutive relation of tensile specimens after necking, we proposed an experimental-numerical combined method (ENM) based on the simple tension test results and finite element analysis (FEA). An iterative scheme was used to minimize the errors between the simulated and experimental load-displacement curves by modifying the imported stress-strain data step by step, and the true stress was determined when the error was less than a given infinitesimal value. In addition, we developed a special program to implement this algorithm automatically and save operating time. As a verification, the true stress-strain curves obtained by the traditional analytical method (TAM) and ENM were compared and employed to analyze the large deformation behavior of both cylindrical and rectangular specimens. The results showed that ENM was applicable for both specimens and could achieve an adequate description of the mechanical response of the materials after necking formation more effectively. You-de Wang, Shan-hua Xu, Song-bo Ren, and Hao Wang Copyright © 2016 You-de Wang et al. All rights reserved. Strengthening Mechanisms of Magnesium-Lithium Based Alloys and Composites Sun, 15 May 2016 11:59:39 +0000 http://www.hindawi.com/journals/amse/2016/1078187/ Mg-Li based alloys are widely applied in various engineering applications. The strength of these alloys is modified and enhanced by different strengthening mechanisms. The strengthening mechanisms of these alloys and their composites have been extensively studied during the past decades. Important mechanisms applied to strengthening the alloys include precipitation strengthening, solution strengthening, grain and subgrain strengthening, and dislocation density strengthening. Precipitation and solution strengthening mechanisms are strongly dependent on composition of the alloys and thermal treatment processes, whereas grain and subgrain and dislocation density strengthening mechanisms majorly depend on thermomechanical processing. In this paper, recent studies on conventional processes for the strengthening of Mg-Li based alloys are summarized as they are critical during the alloys design and processing. Main strengthening mechanisms are objectively reviewed, focusing on their advantages and drawbacks. These can contribute to enhancing, initiating, and improving future researches for alloys design and suitable processing selection. C. O. Muga and Z. W. Zhang Copyright © 2016 C. O. Muga and Z. W. Zhang. All rights reserved. Magnetodielectric and Metalomagnetic 1D Photonic Crystals Homogenization: Local Behavior Thu, 12 May 2016 13:07:41 +0000 http://www.hindawi.com/journals/amse/2016/7451941/ A theory for calculating the effective optic response of photonic crystals with metallic and magnetic inclusions is reported, for the case when the wavelength of the electromagnetic fields is much larger than the lattice constant. The theory is valid for any type of Bravais lattice and arbitrary form of inclusions in the unitary cell. An equations system is obtained for macroscopic magnetic field and magnetic induction components expanding microscopic electromagnetic fields in Bloch waves. Permittivity and permeability effective tensors are obtained comparing the equations system with an anisotropic nonlocal homogenous medium. In comparison with other homogenization theories, this work uses only two tensors: nonlocal permeability and permittivity. The proposal showed here is based on the use of permeability equations, which are exact and very simple. We present the explicit form of these tensors in the case of binary 1D photonic crystals. J. I. Rodríguez Mora, J. Flores Méndez, B. Zenteno Mateo, F. Severiano Carrillo, and R. C. Ambrosio Lázaro Copyright © 2016 J. I. Rodríguez Mora et al. All rights reserved. Frequency Analysis of Functionally Graded Curved Pipes Conveying Fluid Wed, 11 May 2016 12:13:04 +0000 http://www.hindawi.com/journals/amse/2016/7574216/ The curved pipe made of functionally graded material conveying fluid is considered and the in-plane free vibration frequency of the resulting composite pipe is investigated. The material properties are assumed to distribute continuously along the pipe wall thickness according to a power law and the effective mass, flexural rigidity, and mass ratio are used in the governing equations. The natural frequencies are derived numerically by applying the modified inextensible theory. The lowest four natural frequencies are studied via the complex mode method, the validity of which is demonstrated by comparing the results with those in available literatures. A parametric sensitivity study is conducted by numerical examples and the results obtained reveal the significant effects of material distribution gradient index, flow velocity, fluid density, and opening angle on the natural frequencies of the FGM curved pipes conveying fluid. Feng Liang, Xiao-Dong Yang, Ri-Dong Bao, and Wei Zhang Copyright © 2016 Feng Liang et al. All rights reserved. Graphite Intended for Green Engineering Developed by Noncontaminant Reverse Abrasion Wed, 11 May 2016 11:44:28 +0000 http://www.hindawi.com/journals/amse/2016/7016457/ Graphite intended for green engineering was synthesized by noncontaminant reverse abrasion, which consists of graphite layers assembled with thickness controlled on SiC sandpaper as insulating substrate. Phase formation of the graphite layers was validated by X-ray diffraction studies and its finished profile by Atomic Force Microscopy (AFM). Transport parameters of only three layers were evaluated from current-voltage curves. Mathematical functions such as derivative and modulation of a signal have been built by graphite circuits using different performance principles, compared to those used with silicon devices. The trends related to electronic engineering should be achieved with design of the graphite-based devices to facilitate their mass production in the near future. Roberto Baca Arroyo Copyright © 2016 Roberto Baca Arroyo. All rights reserved. Tests and Models of Hydraulic Concrete Material with High Strength Wed, 11 May 2016 09:55:57 +0000 http://www.hindawi.com/journals/amse/2016/8953236/ The paper describes an investigation into the comprehensive sensitivities of Sino high strength hydraulic concrete to the addition levels of fly-ash powder and silica fume. Four fly-ash powder addition schemes (100, 120, 140, and 160 kg/m3) and four silica fume addition schemes (12.5, 17.5, 22.5, and 27.5 kg/m3) were considered, respectively. The curing ages’ effects were incorporated in this study. The sensitive feedbacks, including creep development, temperature rise procedure, and strain-stress constitution, have been analyzed. The simulation and test results indicate that the Sino high strength hydraulic concrete, prepared by 140 kg/m3 fly-ash powder and 22.5 kg/m3 silica fume, gives the superb strength, durability, and creep stability. Yajun Wang Copyright © 2016 Yajun Wang. All rights reserved. Experimental Study on the Properties of Concrete Mixed with Iron Ore Tailings Tue, 10 May 2016 16:25:52 +0000 http://www.hindawi.com/journals/amse/2016/8606505/ The objective of this study is to evaluate the modified performance of concrete with mixing of iron ore tailings in order to solve the shortage of natural sand and make full use of industrial waste. Firstly, the raw materials of mixing were analyzed, and the test ratio was determined. Secondly, the workability and mechanical property of concrete specimens with different amounts of iron ore tailings as replacement were tested. Results show that 35% replacement of natural aggregate by iron ore tailings is optimal. Finally, tests of impermeability, frost resistance, and carbonation resistance were further performed for the concrete specimens with optimal amount of iron ore tailings. The compression performance of the specimens after a durability test was determined. The change in the mechanical properties of the specimens was obtained after seepage, freezing-thawing, and carbonation. Findings showed that the performance of the concrete with 35% replacement of iron ore tailings is basically equivalent to that of natural sand concrete. Hence, it can be utilized in engineering applications. Zhong-xi Tian, Zeng-hui Zhao, Chun-quan Dai, and Shu-jie Liu Copyright © 2016 Zhong-xi Tian et al. All rights reserved. Processing and Quality Evaluation of Additive Manufacturing Monolayer Specimens Tue, 10 May 2016 13:27:06 +0000 http://www.hindawi.com/journals/amse/2016/5780693/ Although its importance has increased significantly, Additive Manufacturing is not yet a fully accepted industrial manufacturing process for load-carrying parts. The future success of the process group depends on its standardization. This work proposes a methodology for the design, manufacturing, and quality evaluation of specimens manufactured by Fused Layer Modeling that are composed of only one layer (so-called monolayers). The processing methodology and properties of monolayers have not been studied systematically yet. A first systematic design of monolayers for mechanical testing is presented. Rectangular and circular monolayers adapted to the loads of tensile and compression testing are manufactured using different trajectory strategies. Frequently occurring macro- and microgeometrical defects are evaluated and categorized in order to optimize the part quality. This work also studies the effect of some manufacturing parameters such as the gap between print head and machine bed, trajectory strategy, bed leveling, and temperatures on part quality. The most suitable specimens are tested mechanically in tensile or compression tests. In the case of study, tensile strength values are only 8.6% lower than the values for reference tests on the unextruded filament. However, the properties deviate more strongly for compression tests which may be due to the selected specimen geometry. Christiane Wendt, Severo Raúl Fernández-Vidal, Álvaro Gómez-Parra, Moisés Batista, and Mariano Marcos Copyright © 2016 Christiane Wendt et al. All rights reserved. Photon Conversion and Radiation Synergism in Eu/Tb Complexes Incorporated Poly Methyl Methacrylate Tue, 10 May 2016 06:57:06 +0000 http://www.hindawi.com/journals/amse/2016/2618253/ Green and red emissions in terbium and europium benzoic acids (TBA and EBA) incorporated poly methyl methacrylates (PMMA) are exhibited. Larger intensity parameters ( cm2) and ( cm2) of indicate a high inversion asymmetrical and strong covalent environment around lanthanide (Ln) ions and maximum emission cross section ( cm2) for the dominant transition of reveals the effective photon conversion capacity in EBA incorporated PMMA. Color variation and fluorescence enhancement are validated to be originated from energy transfer and synergistic effect in TBA/EBA coincorporated PMMA system. The results indicate that Eu and Tb complexes incorporated PMMA with effective photon conversion hold great prospect in increment of lighting quality and enhancement of solar-cell efficiency employed in outer space. P. Xiao, J. J. Zhang, Z. Q. Wang, and H. Lin Copyright © 2016 P. Xiao et al. All rights reserved.