Advances in Materials Science and Engineering The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Magnetic Properties and Core Loss Behavior of Fe-6.5wt.%Si Ribbons Prepared by Melt Spinning Mon, 26 Jan 2015 14:31:48 +0000 Fe-6.5wt.%Si alloy is prepared in the form of continuous ribbons with 25 mm in width and 0.03 mm in thickness by using melt spinning technique. The ribbons are flexible and could be wounded into tapes. DC magnetic properties and core loss behaviors of the ribbons after heat treatment are investigated in this paper. The magnetic properties are compared with ribbons by cold rolling and CVD methods. The melt spinning ribbons exhibit much less core loss in the frequencies more than 10 kHz. The melt spinning ribbons are promising to be used for electric devices used in medium or higher frequencies. S. Wang, Y. M. Jiang, Y. F. Liang, F. Ye, and J. P. Lin Copyright © 2015 S. Wang et al. All rights reserved. Correlation of Grain Size, Stacking Fault Energy, and Texture in Cu-Al Alloys Deformed under Simulated Rolling Conditions Mon, 26 Jan 2015 13:07:27 +0000 The effect of grain size and stacking fault energy (SFE) on the strain hardening rate behavior under plane strain compression (PSC) is investigated for pure Cu and binary Cu-Al alloys containing 1, 2, 4.7, and 7 wt. % Al. The alloys studied have a wide range of SFE from a low SFE of 4.5 mJm−2 for Cu-7Al to a medium SFE of 78 mJm−2 for pure Cu. A series of PSC tests have been conducted on these alloys for three average grain sizes of ~15, 70, and 250 m. Strain hardening rate curves were obtained and a criterion relating twinning stress to grain size is established. It is concluded that the stress required for twinning initiation decreases with increasing grain size. Low values of SFE have an indirect influence on twinning stress by increasing the strain hardening rate which is reflected in building up the critical dislocation density needed to initiate mechanical twinning. A study on the effect of grain size on the intensity of the brass texture component for the low SFE alloys has revealed the reduction of the orientation density of that component with increasing grain size. Ehab A. El-Danaf, Mahmoud S. Soliman, and Ayman A. Al-Mutlaq Copyright © 2015 Ehab A. El-Danaf et al. All rights reserved. Analysis of Disturbing Influence of Traffic Load on Soil Body Mon, 26 Jan 2015 07:29:46 +0000 Stress waves propagate in soil in case of earthquake and man-made effects (traffic flow, buried explosions, shield-driven pipes and tunnels, etc.). The wave point-sources are those located at the distances equal to more than two waves lengths, which significantly simplifies solving of a problem of these waves’ strength evaluation. Distribution of stress and displacement by the stress waves propagation in elastic medium is a complex pattern. The stress distribution in propagating waves depends on the type and form of source, conditions of the source contact with medium, and properties of mediums in the vicinity of the source. The point-sources and their combinations are selected in such a way to model an influence of machines and processes on soil body in case of shield-driven pipes (tunnels). Janat Musayev and Algazy Zhauyt Copyright © 2015 Janat Musayev and Algazy Zhauyt. All rights reserved. The Phase-Formation Behavior of Composite Ceramic Powders Synthesized by Utilizing Rice Husk Ash from the Biomass Cogeneration Plant Mon, 26 Jan 2015 06:26:57 +0000 The development and utilization of biomass as a vital source of renewable energy were stimulated in order to reduce the global dependency on fossil fuels. A lot of rice husk ashes (RHA) were generated as the waste after the rice husk as the main fuel was burnt in the biomass cogeneration plant. The phase-formation behavior of composite ceramic powders synthesized by using rice husk ash from the biomass cogeneration plant at the different carbon ratios and temperatures was investigated. The sequence of phase formation with the calcining temperatures ranging from 1773 K to 1853 K was followed by O′-SialonSiC + Si3N4SiC in samples with C/SiO2  =  1 : 1–4 : 1. Ca--Sialon formed in samples with C/SiO2  =  5 : 1 and 6 : 1. The results highlighted that series of reactions happening sensitively depended on C/SiO2 and the temperature and demonstrated that the carbothermal nitridation provided an alternative for converting RHA waste into composite ceramic powders. Wenjie Yuan, Mingyu Fan, Chengji Deng, Jun Li, and Hongxi Zhu Copyright © 2015 Wenjie Yuan et al. All rights reserved. Experimental Study on Dry Friction Damping Characteristics of the Steam Turbine Blade Material with Nonconforming Contacts Thu, 22 Jan 2015 13:27:03 +0000 An experiment system has been established to study the dry friction damping dynamic characteristics of the steam turbine blade material 1Cr13. The friction dynamic characteristics of the specimens with nonconforming contact surfaces are measured under different parameters. The experiment results are compared with that of the macroslip hysteresis model and the Mindlin microslip friction model in detail. The results show that the experimental result of the tangential contact stiffness is in good agreement with that of the theory result based on the fractal theory and the Hertz contact theory by Jiang et al., 2009. The dimensionless equivalent stiffness and equivalent damping obtained by the macroslip hysteresis model agree well with the experimental results when relative motion is relatively large. However, the results of the macroslip hysteresis model differ a lot from the experimental results when relative motion is relatively small. Compared with the macroslip hysteresis model, the Mindlin microslip friction model can predict the dimensionless equivalent stiffness and equivalent damping accurately during the whole measurement range. The linear regularities of dimensionless equivalent stiffness and equivalent damping are obtained, which decrease the difficulty of building the vibration analysis model of the blade with sufficient accuracy. Jun Wu, Ruishan Yuan, Zhenwu He, Di Zhang, and Yonghui Xie Copyright © 2015 Jun Wu et al. All rights reserved. A Precipitation Phenomenon of Titanium Compounds in Aluminum Melts and the Refinement Fading Mechanism of the Al-5Ti-0.62C Master Alloy Thu, 22 Jan 2015 06:28:05 +0000 The Al-5Ti-0.62C master alloy was prepared through a method of thermal explosion in molten aluminum. The process of remelting and refining of commercially pure aluminum was conducted, and precipitation samples with different heat-treatment times were obtained. Scanning electron microscopy (SEM), X-ray diffraction (XRD), optical microscopy (OM), and other techniques were used to analyze the microstructure of the precipitates at the bottom of the samples so as to explore the fading mechanism of Al-Ti-C alloy refinement. The results showed that an obvious precipitation phenomenon of titanium compounds existed in the remelted Al-5Ti-0.62C master alloy and that there were both TiC compounds and TiAl3 compounds in the precipitates; in the refined pure aluminum samples, the precipitates were mainly TiC compounds. Precipitation of titanium compounds in aluminum melting is the main cause of fading in the refinement effect of an Al-Ti-C master alloy. Wanwu Ding, Wenjun Zhao, and Tiandong Xia Copyright © 2015 Wanwu Ding et al. All rights reserved. Microstructures and Toughening of TiC-TiB2 Ceramic Composites with Cr-Based Alloy Phase Prepared by Combustion Synthesis in High-Gravity Field Tue, 20 Jan 2015 10:38:49 +0000 Micro-nanocrystalline microstructures which are characterized by TiB2 platelets of the average thickness close to or smaller than 1 μm can be achieved in nearly full-density solidified TiC-TiB2 ceramic composites with Cr-based alloy phases by combustion synthesis in ultra-high gravity field of 2500 g. The filler phases in ceramic composites are actually Cr-based alloy with a little solidified solution of Ni atoms and Al atoms. The hardness, flexural strength, and fracture toughness of the materials are 18.5 ± 1.5 GPa, 650 ± 35 MPa, and 16.5 ± 1.5 MPa⋅m0.5, respectively. The improved fracture toughness of TiC-TiB2 ceramic composites results from crack deflection, crack bridging, and pull-out by a large number of fine TiB2 platelets and plastic deformation with some Cr-based alloy phases. Xuegang Huang, Chun Yin, Zhongmin Zhao, Long Zhang, and Junyan Wu Copyright © 2015 Xuegang Huang et al. All rights reserved. Optimized Design of an ECAP Die Using the Finite Element Method for Obtaining Nanostructured Materials Tue, 20 Jan 2015 07:02:39 +0000 An alloy type A16060 was exposed to severe plastic deformation to study its reaction using the finite element method (FEM). To perform this, six different configurations were used in the design of the die’s channel for ECAP (equal channel angular pressing) to obtain nanostructure materials and to optimize the process. Thanks to simulation performed with FEM, it is possible to study the homogeneity in the deformation due to the variation of conditions affecting directly the material being processed using the ECAP technique, such as the friction coefficient, extrusion speed, and mainly the die’s channel geometry being utilized in the ECAP process. Due to the tensile strain area being located mainly in the upper part of the deformed test cylinder (plastic deformation area) which increases the fracture and cracking tendency preventing the processing through ECAP the die being utilized was modified to eliminate the tensile strain area favoring the appearance of compressive stress which reduces the cracking tendency and the fracture of the sample being processed. The FEM analysis demonstrated that the strain state changed significantly from tension to compression when the modified die was used, facilitating the processing of the piece by ECAP. Patricia Ponce-Peña, Edgar López-Chipres, Edgar García-Sánchez, Miguel Angel Escobedo-Bretado, Brenda Xiomara Ochoa-Salazar, and María Azucena González-Lozano Copyright © 2015 Patricia Ponce-Peña et al. All rights reserved. Water Permeability of Pervious Concrete Is Dependent on the Applied Pressure and Testing Methods Sun, 18 Jan 2015 09:34:15 +0000 Falling head method (FHM) and constant head method (CHM) are, respectively, used to test the water permeability of permeable concrete, using different water heads on the testing samples. The results indicate the apparent permeability of pervious concrete decreasing with the applied water head. The results also demonstrate the permeability measured from the FHM is lower than that from the CHM. The fundamental difference between the CHM and FHM is examined from the theory of fluid flowing through porous media. The testing results suggest that the water permeability of permeable concrete should be reported with the applied pressure and the associated testing method. Yinghong Qin, Haifeng Yang, Zhiheng Deng, and Jiang He Copyright © 2015 Yinghong Qin et al. All rights reserved. Aluminium Process Fault Detection and Diagnosis Thu, 15 Jan 2015 11:27:42 +0000 The challenges in developing a fault detection and diagnosis system for industrial applications are not inconsiderable, particularly complex materials processing operations such as aluminium smelting. However, the organizing into groups of the various fault detection and diagnostic systems of the aluminium smelting process can assist in the identification of the key elements of an effective monitoring system. This paper reviews aluminium process fault detection and diagnosis systems and proposes a taxonomy that includes four key elements: knowledge, techniques, usage frequency, and results presentation. Each element is explained together with examples of existing systems. A fault detection and diagnosis system developed based on the proposed taxonomy is demonstrated using aluminium smelting data. A potential new strategy for improving fault diagnosis is discussed based on the ability of the new technology, augmented reality, to augment operators’ view of an industrial plant, so that it permits a situation-oriented action in real working environments. Nazatul Aini Abd Majid, Mark P. Taylor, John J. J. Chen, and Brent R. Young Copyright © 2015 Nazatul Aini Abd Majid et al. All rights reserved. Adsorption of Atenolol on Kaolinite Sun, 11 Jan 2015 12:37:58 +0000 In this study the adsorption of atenolol (AT), a -blocker, on kaolinite, a clay mineral of low surface charge, was investigated under varying initial AT concentration, equilibrium time, solution pH, ionic strength, and temperature conditions. The results showed that the amounts of AT uptake by kaolinite were close to its cation exchange capacity value and the AT adsorption was almost instantaneous, suggesting a surface adsorption. The adsorption was exothermic and the free energy of adsorption was small negative, indicating physical adsorption. The increase in ionic strength of the solution drastically reduced AT uptake on kaolinite. A significant reduction in AT uptake was found at solution pH below 5 or above 10. The FTIR results showed band shifting and disappearance for NH bending vibration and benzene ring skeletal vibration at 3360 and 1515 cm−1 and band splitting at 1412 and 1240 cm−1 attributed to C–N valence vibration coupled with NH bending vibrations and alkyl aryl ether linkage, suggesting the participation of NH, –O–, and benzene ring for AT adsorption on kaolinite. Yingmo Hu, Nicole M. Fitzgerald, Guocheng Lv, Xuebing Xing, Wei-Teh Jiang, and Zhaohui Li Copyright © 2015 Yingmo Hu et al. All rights reserved. Studying the Effect of ZnO on Physical and Elastic Properties of (ZnO)x(P2O5)1−x Glasses Using Nondestructive Ultrasonic Method Tue, 06 Jan 2015 14:41:24 +0000 Binary zinc phosphate glass system with composition of (ZnO)x(P2O5)1−x, ( = 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 mol%) was successfully prepared using a conventional melt-quenching method. Composition dependence of physical properties and elastic properties in the (ZnO)x(P2O5)1−x were discussed in association with the effects of adding zinc oxide (ZnO) as a modifier. The addition of ZnO modifier was expected to produce substantial changes on physical properties of the phosphate glasses. An increase in density values of the phosphate glasses was observed. Elastic moduli were studied by measuring ultrasonic longitudinal and shear velocities ( and ) of the glasses at room. Longitudinal modulus, shear modulus, bulk modulus, Young’s modulus, Poisson’s ratio, and Debye temperature were derived from both data of velocities and respective density of all of the samples. Findings from present work showed dependence of density and elastic moduli of each ZnO-P2O5 series on glass composition. Khamirul Amin Matori, Mohd Hafiz Mohd Zaid, Hock Jin Quah, Sidek Hj. Abdul Aziz, Zaidan Abdul Wahab, and Mohd Sabri Mohd Ghazali Copyright © 2015 Khamirul Amin Matori et al. All rights reserved. Microstructure and Wear Behavior of CoCrFeMnNbNi High-Entropy Alloy Coating by TIG Cladding Tue, 06 Jan 2015 07:08:30 +0000 Alloy cladding coatings are widely prepared on the surface of tools and machines. High-entropy alloys are potential replacements of nickel-, iron-, and cobalt-base alloys in machining due to their excellent strength and toughness. In this work, CoCrFeMnNbNi HEA coating was produced on AISI 304 steel by tungsten inert gas cladding. The microstructure and wear behavior of the cladding coating were studied by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometer, microhardness tester, pin-on-ring wear tester, and 3D confocal laser scanning microscope. The microstructure showed up as a nanoscale lamellar structure matrix which is a face-centered-cubic solid solution and niobium-rich Laves phase. The microhardness of the cladding coating is greater than the structure. The cladding coating has excellent wear resistance under the condition of dry sliding wear, and the microploughing in the worn cladding coating is shallower and finer than the worn structure, which is related to composition changes caused by forming the nanoscale lamellar structure of Laves phase. Wen-yi Huo, Hai-fang Shi, Xin Ren, and Jing-yuan Zhang Copyright © 2015 Wen-yi Huo et al. All rights reserved. Fabrication and Characterization of Nickel Chloride Doped PMMA Films Thu, 01 Jan 2015 13:55:59 +0000 Films of PMMA and PMMA doped with NiCl2 with different contents were prepared using the casting technique. The optical properties of all films were investigated using spectrophotometric measurements of absorbance and transmittance in the wavelength range 200–800 nm. The change of the calculated values of the optical energy gaps with increasing NiCl2 content has been interpreted in terms of the structural modifications of the PMMA matrix. The optical energy gap decreased from 3.6 to 3.05 eV with increasing the NiCl2 concentration to 0.4%. The effect of doping on the optical constants of films such as refractive index, extinction coefficient, real and imaginary parts of dielectric constant, optical conductivity, and skin depth has been reported. All these constants were increased with increasing NiCl2 concentration with the exception of skin depth which is different result. Wasan A. Al-Taa’y, Saad F. Oboudi, Emad Yousif, Mohammed Abdul Nabi, Rahimi M. Yusop, and Darfizzi Derawi Copyright © 2015 Wasan A. Al-Taa’y et al. All rights reserved. Experimental and Theoretical Advances in Amorphous Alloys Wed, 31 Dec 2014 13:12:57 +0000 Na Chen, Limei Xu, Yang Shao, and Konstantinos Georgarakis Copyright © 2014 Na Chen et al. All rights reserved. Test Study on Airtight Capability of Filter Cakes for Slurry Shield and Its Application in a Case Wed, 31 Dec 2014 08:05:03 +0000 To learn the airproof capacity of filter cakes as opening chambers under air pressure, a series of tests were carried out. The variations of discharged water with air pressure and time were observed, and the relationship between airproof capacity of filter cakes and surrounding air pressure was analysed. The test results indicated that there were three stages as compressed air acting on filter cakes: completely not infiltration, a very small amount of infiltration, and penetration leakage. The certain air pressure between the first and second stages was called the airproofing value of filter cake. And a capillary bundle model was used to explain the mechanism of air tightness of filter cakes. In Nanjing Yangtze River Tunnel, a 5 cm thickness filter cake was formed in gravel sand, and its airproofing value was a little lower than 0.12 MPa. The air pressure used as opening chamber should be equal to the summation of water pressure in sand and airproofing value of filter cake. While the air pressure is larger than the summation, the filter cake would be gas permeable. The slurry formulation and airproofing value of filter cakes obtained in the tests were applied successfully in Nanjing Yangtze River Tunnel. Fanlu Min, Wei Zhu, Shengquan Xia, Rui Wang, Daiwei Wei, and Teng Jiang Copyright © 2014 Fanlu Min et al. All rights reserved. High Temperature Corrosion of Inconel 600 in NaCl-KCl Molten Salts Tue, 30 Dec 2014 08:39:24 +0000 In this work the corrosion resistance of a high content nickel alloy, Inconel 600, was investigated in mixed NaCl-KCl salts at 700, 800, and 900°C for 100 hours in static air. Investigation was carried out using electrochemical techniques such as polarization curves, rest potential measurements, linear polarization resistance, and electrochemical impedance spectroscopy. Corroded specimens were analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Electrochemical measurements showed an increased degradation rate of Inconel 600 with increasing test temperature. SEM and EDS analysis show that the damage experienced by Inconel 600 is greater than that determined by electrochemical measurements. This damage was identified as internal corrosion due to the reaction of Cl2 with the alloying elements (Cr and Fe); however, at 900°C the internal damage was minor and it was associated with the nickel content in the alloy. G. Salinas-Solano, J. Porcayo-Calderon, J. G. Gonzalez-Rodriguez, V. M. Salinas-Bravo, J. A. Ascencio-Gutierrez, and L. Martinez-Gomez Copyright © 2014 G. Salinas-Solano et al. All rights reserved. Influences of Mg Doping on the Electrochemical Performance of TiO2 Nanodots Based Biosensor Electrodes Mon, 29 Dec 2014 00:10:33 +0000 Electrochemical biosensors are essential for health monitors to help in diagnosis and detection of diseases. Enzyme adsorptions on biosensor electrodes and direct electron transfer between them have been recognized as key factors to affect biosensor performance. TiO2 has a good protein adsorption ability and facilitates having more enzyme adsorption and better electron transfer. In this work, Mg ions are introduced into TiO2 nanodots in order to further improve electrode performance because Mg ions are considered to have good affinity with proteins or enzymes. Mg doped TiO2 nanodots on Ti substrates were prepared by spin-coating and calcining. The effects of Mg doping on the nanodots morphology and performance of the electrodes were investigated. The density and size of TiO2 nanodots were obviously changed with Mg doping. The sensitivity of 2% Mg doped TiO2 nanodots based biosensor electrode increased to 1377.64 from 897.8 µA mM−1 cm−2 and its decreases to 0.83 from 1.27 mM, implying that the enzyme achieves higher catalytic efficiency due to better affinity of the enzyme with the Mg doped TiO2. The present work could provide an alternative to improve biosensor performances. M. S. H. Al-Furjan, Kui Cheng, and Wenjian Weng Copyright © 2014 M. S. H. Al-Furjan et al. All rights reserved. Effects of Sb2O3 on the Mechanical Properties of the Borosilicate Foam Glasses Sintered at Low Temperature Sun, 28 Dec 2014 09:47:17 +0000 The physical properties and microstructure of a new kind of borosilicate foam glasses with different Sb2O3 doping content are comprehensively investigated. The experimental results show that appropriate addition of Sb2O3 has positive impact on the bulk porosity and compressive strength of the foam glass. It is more suitable in this work to introduce 0.9 wt.% Sb2O3 into the Na2O-K2O-B2O3-Al2O3-SiO2 basic foam glass component and sinter at 775°C. And the obtained foam glasses present much more uniform microstructure, large pore size, and smooth cell walls, which bring them with better performance including a lower bulk density, low water absorption, and an appreciable compressive strength. The microstructure analysis indicates that, with the increase of the content of Sb2O3 additives, the cell size tends to increase at first and then decreases. Larger amounts of Sb2O3 do not change the crystalline phase of foam glass but increase its vitrification. It is meaningful to prepare the foam glass at a relatively low temperature for reducing the heat energy consumption. Chenxi Zhai, Zhe Li, Yumei Zhu, Jing Zhang, Xiuduo Wang, Lejun Zhao, Liuming Pan, and Pengfei Wang Copyright © 2014 Chenxi Zhai et al. All rights reserved. Ammonothermal Synthesis and Photocatalytic Activity of Lower Valence Cation-Doped LaNbON2 Thu, 25 Dec 2014 00:10:25 +0000 Highly crystalline pure perovskite-type LaNbON2 powders were synthesized in supercritical ammonia using sodium hydroxide as an oxygen source. Additionally, doping LaNbON2 with cations of lower valence than that of the parent cation was performed to inhibit reduction of Nb5+. Various characterization methods indicated that crystallinity, particle morphology, and absorption edge of the product, that is, the factors possibly affecting photocatalytic activity, were not significantly changed by the doping of a lower-valence cation. Nevertheless, the doped LaNbON2 synthesized using the ammonothermal method evolved hydrogen, suggesting that this type of doping decreases the formation of reduced niobium species and consequently enhances the photocatalytic activity of LaNbON2. In case of doped LaNbON2 synthesized using conventional method, no hydrogen evolution was observed. This difference is probably due to the higher crystallinity of ammonothermally synthesized LaNbON2. Therefore, we successfully produced LaNbON2 with improved potential for photocatalytic activity for hydrogen evolution under visible light irradiation using ammonothermal synthesis and lower-valence cation doping. Chihiro Izawa, Takeshi Kobayashi, Kazuhisa Kishida, and Tomoaki Watanabe Copyright © 2014 Chihiro Izawa et al. All rights reserved. A New Mathematical Model for Flank Wear Prediction Using Functional Data Analysis Methodology Wed, 24 Dec 2014 11:26:03 +0000 This paper presents a new approach improving the reliability of flank wear prediction during the end milling process. In the present work, prediction of flank wear has been achieved by using cutting parameters and force signals as the sensitive carriers of information about the machining process. A series of experiments were conducted to establish the relationship between flank wear and cutting force components as well as the cutting parameters such as cutting speed, feed per tooth, and radial depth of cut. In order to be able to predict flank wear a new linear regression mathematical model has been developed by utilizing functional data analysis methodology. Regression coefficients of the model are in the form of time dependent functions that have been determined through the use of functional data analysis methodology. The mathematical model has been developed by means of applied cutting parameters and measured cutting forces components during the end milling of workpiece made of 42CrMo4 steel. The efficiency and flexibility of the developed model have been verified by comparing it with the separate experimental data set. Sonja Jozić, Branimir Lela, and Dražen Bajić Copyright © 2014 Sonja Jozić et al. All rights reserved. Effects of Additives and Sintering Time on the Microstructure of Ni-Zn Ferrite and Its Electrical and Magnetic Properties Wed, 24 Dec 2014 10:45:47 +0000 This work aims to investigate the relationship between the microstructure of Ni-Zn ferrite and its electrical and magnetic properties in the presence and absence of as small amounts as 0.12% of 0.4CaO + 0.8SiO2 over different sintering times. The X-ray diffraction pattern showed a single spinel phase formation in all the samples. The results indicate that grain growth occurred by increasing sintering time from 15 to 270 min in the two types of samples prepared in this study although it was greatly impeded by the additive oxides. Moreover, the oxides increase the resistivity of the ferrite and decrease its zinc loss. Magnetic properties such as induction magnetization () and saturation magnetization () decreased in the presence of the additives while its coercivity () increased. Finally, the density of the samples was observed to increase with increasing sintering time in both types of the samples but with a higher value in the samples with no additives. Abdollah Hajalilou, Mansor Hashim, and Halimah Mohamed Kamari Copyright © 2014 Abdollah Hajalilou et al. All rights reserved. Magnesium Removal from an Aluminum A-332 Molten Alloy Using Enriched Zeolite with Nanoparticles of SiO2 Wed, 24 Dec 2014 09:23:15 +0000 In order to improve the Mg removal from an A-380 molten alloy, mixtures of zeolite and SiO2 nanoparticles () were tested. Zeolite was enriched with 2.5, 5, 7.5, 10, or 12.5 wt-% of amorphous . The and zeolite were mixed for 30 min in ethanol for each experiment and then dried in a furnace at 80°C for 12 h. The enriched zeolites were analyzed by scanning electron microscopy, transmission electron microscopy, and N2 gas adsorption analysis. The Mg removal was carried out injecting each mixture into the molten aluminum alloy at 750°C using argon. The Mg content of the molten alloy was measured after different periods of the injection time. Zeolites enriched with 2.5 and 5 wt-% of were demonstrated to be the better mixtures, removing Mg from an initial content of 1.6 to a final content of 0.0002 and 0.0101 wt-%, respectively, in 45 min of injection. R. Muñoz-Arroyo, H. M. Hdz-García, J. C. Escobedo-Bocardo, E. E. Granda-Gutierrez, J. L. Acevedo-Dávila, J. A. Aguilar-Martínez, and A. Garza-Gomez Copyright © 2014 R. Muñoz-Arroyo et al. All rights reserved. Research of Joining Brittle Nonmetallic Materials with an Active Solder Mon, 22 Dec 2014 14:19:34 +0000 This paper deals with soldering high-purity brittle, nonmetallic materials such as SiO2, Si, and C (graphite). However, these materials exert poor wettability when using tin solder. Therefore, to reduce the wetting angle, an Sn solder alloyed with active Ti element was used. At a soldering temperature of 860°C and 15 min soldering time, the wetting angle on SiO2 ceramics was 30°, on silicon 42°, and on graphite 52°. All these wetting angles are below 90° and are acceptable for soldering. It has been shown that the bond in all joined materials (SiO2, Si, and C) was of a diffusion character. New intermetallic products were formed on the boundary with nonmetal, thus allowing bond formation. The shear strength of SiO2 ceramics attained an average value of 17 MPa. Roman Koleňák and Michal Prach Copyright © 2014 Roman Koleňák and Michal Prach. All rights reserved. Effect of Surface Microstructures on Hydrophobicity and Barrier Property of Anticorrosive Coatings Prepared by Soft Lithography Mon, 22 Dec 2014 13:44:35 +0000 Enhancing the hydrophobicity of organic coatings retards their interaction with water and often leads to better protectiveness over metal corrosion. In this study, a soft lithography method was used to prepare epoxy coatings which showed surface microstructures in high replication to sandpapers. The effect of microstructures on coating’s hydrophobicity and barrier property was investigated. Compared to flat coatings, the microstructured coatings showed much higher water contact angles, which further increased with finer sandpapers. Determined by electrochemical impedance spectroscopy (EIS), the flat coating exhibited a higher anticorrosive performance than the microstructured coatings. With the use of finer sandpaper, the groove size of the corresponding microstructured coating was reduced. And a lower anticorrosive performance was observed since more defects might be formed in a given area of coating during the imprinting process. As the groove size of the coatings was further decreased to 5.7 µm, the microstructures became too small for water to easily penetrate through. Therefore, trapped air acted as an additional barrier and contributed to an increased anticorrosive performance compared to other microstructured coatings. Dawei Zhang, Haiyang Li, Xiaoli Chen, Hongchang Qian, and Xiaogang Li Copyright © 2014 Dawei Zhang et al. All rights reserved. A Review on the Use of Agriculture Waste Material as Lightweight Aggregate for Reinforced Concrete Structural Members Mon, 22 Dec 2014 00:10:26 +0000 The agriculture industry is one of the main industries in the Southeast Asia region due to its favourable conditions for plantations. In fact, Southeast Asia region is the world’s largest producer of palm oil and coconut. Nevertheless, vast plantation of these agriculture products leads to equally large amount of waste materials emanating from these industries. Previously, researchers have attempted to utilize the resulting waste materials such as oil palm shell, palm oil clinker, and coconut shell from these industries as lightweight aggregate to produce structural grade lightweight aggregate concrete. In order to promote the concept of using such concrete for actual structural applications, this paper reviews the use of such agriculture-based lightweight aggregate concrete in reinforced concrete structural members such as beam and slab, which were carried out by researchers in the past. The behaviour of the structural members under flexural, shear, and torsional load was also summarized. It is hoped that the knowledge attained from the paper will provide design engineers with better idea and proper application of design criteria for structural members using such agriculture waste as lightweight aggregate. Kim Hung Mo, U. Johnson Alengaram, and Mohd Zamin Jumaat Copyright © 2014 Kim Hung Mo et al. All rights reserved. The Crystallization, Melting Behavior, and Thermal Stability of Poly(L-lactic acid) Induced by N,N,N′-Tris(benzoyl) Trimesic Acid Hydrazide as an Organic Nucleating Agent Sun, 21 Dec 2014 00:10:29 +0000 N,N,N′-Tris(benzoyl) trimesic acid hydrazide (TTAD), as a novel nucleating agent of poly(L-lactic acid) (PLLA), was synthesized and characterized by FT-IR and 1H NMR. The crystallization, melting behavior, and thermal stability of PLLA induced by TTAD were investigated through DSC, TGA, depolarized-light intensity measurement, and so forth. The crystallization behavior indicated that the presence of TTAD accelerated the overall PLLA crystallization. Compared to neat PLLA, the crystallization onset temperature of PLLA/1%TTAD increased from 101.36°C to 125.26°C, the melt-crystallization peak temperature increased from 94.49°C to 117.56°C, crystallization enthalpy increased from 0.1023 J·g−1 to 33.44 J·g−1 at a cooling rate of 1°C/min from melt, and the crystallization half-time of PLLA/TTAD decreased from 2997.2 s to 108.9 s at 110°C. Moreover, the nonisothermal crystallization measurements also indicated that the crystallization peak became wider and shifted to a lower temperature with increasing cooling rate. With the presence of TTAD, the melting behavior of PLLA was affected significantly, and a double-melting peak occurred due to melting-recrystallization. Thermal stability research showed that there existed one degradation stage of PLLA and PLLA/TTAD samples, and the thermal degradation temperature of PLLA/TTAD decreased compared to neat PLLA. Yan-Hua Cai and Yan-Hua Zhang Copyright © 2014 Yan-Hua Cai and Yan-Hua Zhang. All rights reserved. Influence of Molybdenum Content and MoO Species on the Textural and Structural ZrO2 Properties Thu, 18 Dec 2014 13:28:46 +0000 The present work proposes to study the incorporation of molybdenum into the zirconium oxide precursor (Zr(OH)4), in order to analyze its possible repercussions on the textural and structural zirconia properties (ZrO2). For this, the Zr(OH)4 was synthesized by the sol-gel method and modified with 5, 10, and 15 wt% of molybdenum into the stabilized oxide. The synthesized materials were dried at 120°C for 24 h and then were calcined at 600°C for 3 h. The characterization of the solids was carried out by thermal analysis, X-ray diffraction, nitrogen physisorption, infrared spectroscopy, and scanning electron microscopy. The thermal analyses results showed that the change from the amorphous to the crystalline phase of ZrO2 is shifted to higher temperatures due to the presence of molybdenum content. Tetragonal phase was identified for all synthesized materials, showing a decrease in crystallinity as a function of the metal content. The textural properties were improved due to the incorporation of molybdenum into the ZrO2 structure, developing specific surface areas which are above up to four times the area of pure ZrO2. The synthesized materials presented spherical morphology with particle sizes less than 1 µm, with a change of this morphology for high metal contents (15 wt%) being observed. Alberto Hernández Zapién, Juan Manuel Hernández Enríquez, Ricardo García Alamilla, Guillermo Sandoval Robles, Ulises Páramo García, and Luz Arcelia García Serrano Copyright © 2014 Alberto Hernández Zapién et al. All rights reserved. Novel Technologies and Applications for Construction Materials Thu, 18 Dec 2014 11:28:15 +0000 Gonzalo Martínez-Barrera, Osman Gencel, João Marciano Laredo dos Reis, and Juan José del Coz Díaz Copyright © 2014 Gonzalo Martínez-Barrera et al. All rights reserved. Experimental Investigation of the Variation of Concrete Pores under the Action of Freeze-Thaw Cycles by Using X-Ray CT Thu, 18 Dec 2014 00:11:02 +0000 The variation of concrete pores under the action of freeze-thaw cycles was investigated experimentally by using the X-ray CT. Firstly, the statistical characteristics of pores of concrete specimens were obtained by using the X-ray image analysis. Secondly, the variation of porosity and pore volume of concrete pores were analyzed and discussed by comparing with above characteristics. Thirdly, the failure process of the concrete specimens acted by the freeze-thaw cycles was investigated by scanning the interior of concrete specimens. The results showed that the pore volumes of concrete pores whose volumes were located at the interval [0.5 mm3, 20 mm3] have no big variation in both the amounts and volume of concrete pores, while others were found to have huge change during the process of experiment. The extent of damage acted by the repeated freezing and thawing gradually ranged from surface to complete disintegration of the interior of concrete specimens after 30 cycles of freeze-thaw acting. Jie Yuan, Yang Liu, Hongxia Li, and Baokun Zhang Copyright © 2014 Jie Yuan et al. All rights reserved.