Advances in Materials Science and Engineering

Advances in Materials Science and Engineeringhttp://www.hindawi.comThe latest articles from Hindawi Publishing Corporation© 2010, Hindawi Publishing Corporation. All rights reserved.Anion Effect of Zinc Source on Chemically Deposited ZnS(O,OH) Filmshttp://www.hindawi.com/journals/amse/2009/372708.htmlThe study on the anion effect of different Zn sources—Zn(CH3COO)2, ZnCl2, ZnI2, Zn(NO3)2 and ZnSO4—on the chemical deposition of ZnS(O,OH) films revealed that the growth rate and composition of the ZnS(O,OH) layer depend on the instability constant (pK) value of the corresponding Zn-complex Zn(L)n in the chemical bath solution. In the region of pKZn(NH3)2+>pKZn(L)n the ZnS(O,OH) film's growth rate and ZnS concentration in films increased with the increasing pK value of the used Zn salt complex up to the pK value of the Zn[NH3]2+ complex and decreased in the region where pKZn(NH3)2+<pKZn(L)n. The band gap values (around 3.6 eV in most cases) of deposited ZnS(O,OH) films did not depend on the Zn precursor's instability constant, the ZnS(O,OH) film from zinc nitrate containing bath has higher band gap energy (Eg = 3.8 eV). The maximum efficiency of CISSe and CZTSSe monograin layer solar cells was gained with ZnS(O,OH) buffer layer deposited from CBD solution containing Zn(CH3COO)2 as Zn source, which provided the highest growth rate and ZnS concentration in the ZnS(O,OH) film on glass substrates.K. Ernits, K. Muska, M. Danilson, J. Raudoja, T. Varema, O. Volobujeva, and M. Altosaar© 2010, Hindawi Publishing Corporation. All rights reserved.The Effect of Novel Binary Accelerator System on Properties of Vulcanized Natural Rubberhttp://www.hindawi.com/journals/amse/2009/916467.htmlThe mechanical properties, curing characteristics, and swelling behaviour of vulcanized natural rubber with a novel binary accelerator system are investigated. Results indicate that the mechanical properties were improved. Crosslinking density of vulcanized natural rubber was measured by equilibrium swelling method. As a result, the new binary accelerator was found to be able to improve both cure rate and crosslinking density. Using the numerical analysis of test interaction between binary accelerator and operational modelling of vulcanization-factors experiments, it can be concluded that the interaction (Cystine, N-cyclohexyl-2-benzothiazyl sulfenamide) was significant and the optimum value of binary accelerator was suggested, respectively, at levels 0 and +1.Moez Kamoun, Abdallah Nassour, and Nelles Michael© 2010, Hindawi Publishing Corporation. All rights reserved.NTCR Behavior of La-Doped BaBiO3 Ceramicshttp://www.hindawi.com/journals/amse/2009/383842.htmlThe influence of the composition on the microstructure and electrical properties of BaBi1-xLaxO3  (0≤x≤0.1) NTC thermistors was investigated. A single phase of BaBi1−xLaxO3 with a monoclinic structure was prepared by solid state reaction method. The relationship between the resistivity and the reciprocal of absolute temperature of the prepared NTC thermistors was linear, indicative of NTC characteristics. The resistivity and the coefficient of temperature sensitivity first decreased with increasing x in the range of x<0.03 and then increased with further increase in x. However the alpha parameter value increased to a maximum value and then decreased again.Ying Luo, Xvqiong Li, and Xinyu Liu© 2010, Hindawi Publishing Corporation. All rights reserved.Preparation and In Vitro Behavior of a Poly(lactic acid)-Fiber/Hydroxyapatite Composite Sheethttp://www.hindawi.com/journals/amse/2009/827241.htmlThis paper describes the processing and in vitro behavior of a poly(lactic acid) (PLA)-fiber/hydroxyapatite (HA) composite sheet consisting of a knitted PLA-fiber sheet and HA powder for bone tissue engineering. Type I collagen was used as a binding agent to combine the PLA fibers and the HA powder. Precipitate formation in Hanks' balanced salt (HBS) solution was monitored to evaluate the in vitro apatite formation ability of the PLA-fiber/HA composite sheet. Precipitate formation was observed on the surface of the PLA-fiber/HA composite sheet after immersion in HBS solution for only 1 day, while no precipitate formation was observed on the PLA-fiber sheet without HA as a control. In conclusion, a PLA-fiber/HA composite sheet for use as a scaffold was successfully prepared. Within the limitations of this investigation, we confirmed that the PLA-fiber/HA composite sheet has a high apatite formation activity compared with the PLA-fiber sheet and represents a promising material for use as a scaffold.Yasuhiro Tanimoto and Norihiro Nishiyama© 2010, Hindawi Publishing Corporation. All rights reserved.Systematic Investigation of Gettering Effects on 4th Row Element Impurities in Si by Dopant Atomshttp://www.hindawi.com/journals/amse/2009/309209.htmlThe gettering of 4th row element impurities (K, Ca, 3d transition metals, and Zn) in Si crystals by dopant atoms was systematically investigated by first-principles calculation through evaluation of the diffusion barrier and the binding energy. The dopant atoms considered include p-type dopants (B), n-type dopants (P, As, Sb), or light elements (C, O). It was found that (1) the diffusion barrier of impurity atoms decreases with an increase in their atomic number up to Ni, (2) B atom becomes an efficient gettering center for metals except for Ni, (3) most of the metals except for Fe and Co cannot be gettered by n-type dopants, and (4) C and O atoms alone do not become efficient gettering centers for the metals used in actual LSI processes. The vacancy Vc and n-type dopant complexes (PVc, AsVc, SbVc) can be efficient gettering centers for Cu in n/n+ epitaxial wafers.Koji Sueoka, Ken Kamimura, and Seiji Shiba© 2010, Hindawi Publishing Corporation. All rights reserved.Dielectric Spectroscopy Analyses of SrBi4Ti4O15 Films Obtained from Soft Chemical Solutionhttp://www.hindawi.com/journals/amse/2009/928545.htmlSrBi4Ti4O15 (SBTi) thin films were deposited by the polymeric precursor method on Pt bottom electrodes. The obtained films were characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and dielectric spectroscopy analyses. The capacitance-voltage (C-V) characteristics of perovskite thin film showed normal ferroelectric behavior. The remanent polarization and coercive fields were 5.4 μC/cm2 and 85 kV/cm, respectively. Dielectric spectroscopy was employed to examine the polycrystalline behavior of ferroelectric material and the mechanisms responsible for the dielectric performance of the thin film.A. Z. Simões and C. S. Riccardi© 2010, Hindawi Publishing Corporation. All rights reserved.Plasma Spraying and Characterization of Tungsten Carbide-Cobalt Coatings by the Water-Stabilized System WSPhttp://www.hindawi.com/journals/amse/2009/254848.htmlTungsten carbide-cobalt powders (WC-17wt% Co) were plasma sprayed by a water-stabilized system WSP. Experiments with variable feeding distances and spray distances were carried out. Thinner coatings were deposited on carbon steel substrates and thicker coatings on stainless steel substrates to compare different cooling conditions. Basic characterization of coatings was done by XRD, SEM, and light microscopy plus image analysis. Microhardness was measured on polished cross-sections. The main focus of investigation was resistance against wear in dry as well as wet conditions. The appropriate tests were performed with set-ups based on ASTM G65 and G75, respectively. The influence of spray parameters onto coating wear performance was observed. The results of mechanical tests were discussed in connection with changes of phase composition and with the quality of the coating's microstructure. The results show that for obtaining the best possible WC-17Co coating with WSP process, from the viewpoint of wear resistance, the desired parameters combination is long feeding distance combined with short spray distance.Pavel Ctibor, Micheala Kašparová, Jeremy Bellin, Emmanuel Le Guen, and František Zahálka© 2010, Hindawi Publishing Corporation. All rights reserved.Synthetic Conditions and Color Characteristics of Tantalum Oxynitride Prepared via Liquid-NH3 Processhttp://www.hindawi.com/journals/amse/2009/436729.htmlTantalum oxynitrides, such as TaON, exhibit promising color properties and can be employed as nontoxic yellow pigments containing no heavy metals. We have developed a process for preparing nitrides or oxynitrides involving the vacuum-calcination of a precursor material obtained via reaction between a metal halide and liquid NH3. Herein, we describe the synthetic conditions of the liquid-NH3 process that affect the color, and thus the color characteristics, of the resulting pigments. Reaction and postreaction treatment conditions were adjusted to obtain the desired yellow color. The liquid-NH3 process was performed using 1.0 eq of H2O (relative to TaCl5) as the oxygen source and 30.0 eq of KCl (relative to TaCl5) as flux. Calcination of the precursor at 1073 K under vacuum was followed by recalcination from room temperature to 973 K at rate of 10 K min−1 under air. A powder with a color index of L∗=84.20, a∗=−2.71, and b∗=44.07 was obtained.Yo Sasaki, Zentaro Tokuyasu, Yoichi Ono, Mitsunobu Iwasaki, and Seishiro Ito© 2010, Hindawi Publishing Corporation. All rights reserved.Temperature Dependent Electrical Properties and Catalytic Activities of La2O3–CO2–H2O Phase Systemhttp://www.hindawi.com/journals/amse/2009/612130.htmlWe present a study of electrical properties and catalytic activities of materials belonging to the hydrated carbonated system La2O3–CO2–H2O. The polycrystalline hydroxycarbonate, dioxycarbonate, and oxide are prepared via a coprecipitation route followed by heat treatment. The electrical conduction of the phases obtained by thermal decomposition from LaOHCO3, H2O is analyzed by electrical impedance spectroscopy, from 25°C to 950°C, under air. The catalytic properties of LaOHCO3, La2O2CO3 and La2O3 polycrystalline phases are studied by FTIR spectroscopy, in presence of gas mixtures CO-air and CH4-air, at temperatures ranging between 100°C to 525°C. The three materials behave differently in presence of CO or CH4 gases.Bahcine Bakiz, Frédéric Guinneton, Madjid Arab, Sylvie Villain, Abdeljalil Benlhachemi, and Jean Raymond Gavarri© 2010, Hindawi Publishing Corporation. All rights reserved.The Possibility of Correlation of Hardening Power for Oils and Polymers of Quenching Mediumshttp://www.hindawi.com/journals/amse/2009/843281.htmlThere are many literature references comparing the use of aqueous polymer quenching solutions with petroleum oil quenchants for a wide range of steels of varying hardenability and the relating parameters of describing properties of the quenching mediums. There are relatively little similar relating correlations between parameters of describing properties of the different quenching mediums. The quenchants used included: conventional quenching oil, martempering oil, and 5% and 25% aqueous polymer quenchant solutions (APQSs) of a polymer quenchant. These quenching media were selected to represent a broad range of quench severities as quantified by cooling curve analysis (ASTM D 6482) using a standard Inconel 600 probe and the Tensi Agitation Device. The test of correlation conducted between the Hardening Power parameters according to examples of oils and polymers. The enable work results in applying the Hardening Power independently from equation calculated for different quenching mediums and their work parameters.Małgorzata Przyłęcka and Wojciech Gęstwa© 2010, Hindawi Publishing Corporation. All rights reserved.Heat Flux of a Transferred Arc Driven by a Transverse Magnetic Fieldhttp://www.hindawi.com/journals/amse/2009/782048.htmlTheoretical consideration of a magnetically driven arc was performed to elucidate the variation of heat flux with an imposed DC magnetic field. Experiments were conducted to confirm the validity of the theoretical model. The heat flux decreased concomitantly with increased imposed magnetic flux density. Theoretical predictions agreed with experimental results.Naomi Matsumoto, Takashi Usami, Ikumi Kuno, Takeo Yamamoto, Masaya Sugimoto, Seiji Kumagai, and Koichi Takeda© 2010, Hindawi Publishing Corporation. All rights reserved.Selectivity of Na-Montmorillonite versus Concentration of Two Competitive Bivalent Cations (Cu2+, Pb2+): Quantitative XRD Investigationhttp://www.hindawi.com/journals/amse/2009/385673.htmlThe goal of this paper is to examine, by quantitative XRD analysis, the effect of heavy metal cation concentrations (Pb2+, Cu2+) on the selectivity phenomenon in the case of dioctahedral smectite (i.e., Na-montmorillonite). The quantitative XRD analysis is achieved using an indirect method based on the comparison of experimental XRD profiles to those calculated using structural models. The obtained results show that for strong metals concentrations (i.e., 10−1N), the host material presents heterogeneous structure characterized by interstratified hydration states between 1 W and 2 W (i.e., respectively, one and two water layer hydration state) attributed to Pb2+ cation. For low concentration, the d001 values investigation indicates that montmorillonite remains saturated with Na+ characterized by homogeneous 1 W hydration state.W. Oueslati, M. Meftah, H. Ben Rhaiem, and A. Ben Haj Amara© 2010, Hindawi Publishing Corporation. All rights reserved.Conformational Study of Polypeptide Chains Grafted on the Surface of Polylactide Latex Particlehttp://www.hindawi.com/journals/amse/2009/196950.htmlPolylactide (PLA) latex particle covered with polypeptide chains were prepared by means of solvent exchange method from PLA and PLA-block-polypeptide block copolymer solutions. PLA segment of the block copolymer and PLA homopolymer formed a core of the particle, and the polypeptide segment of the block copolymer, which is designed as tightly fixed biodegradable emulsifier, formed corona around the particle surface. This picture was supported by the fact that zeta-potential of PLA latex particle covered with polypeptide segment was different from that of bare PLA particle because of the presence of the ionizable group in the polypeptide chains. To clarify the effect of the ionizable group on conformation of the polypeptide chain, the relation between the polypeptide chain length and the area occupied by the single block chain was evaluated. The result that the occupied area per a polypeptide chain was linearly increased with the increase in the polypeptide chain length indicates that the polypeptide chains trail on the particle surface and did not take helical structures.Satoshi Tanimoto, Toshiya Iwata, Hitoshi Yamaoka, Masahiro Yamada, and Kana Kobori© 2010, Hindawi Publishing Corporation. All rights reserved.Self-Assembly of Cluster-Based Nanoscopic Supramolecules into One-Dimensional Coordination Polymershttp://www.hindawi.com/journals/amse/2009/579123.htmlOctahedral metal clusters [Nb6Cl12(CN)6]4−, (Mn(Salen))+ (or (Mn(7-MeSalen))+) (Salen = N,N′-ethylene-bis-(salicylidene)iminate) and ditopic organic linkers (4,4′-bpe (trans-1, 2-bis(4-pyridyl)-ethylene) or 4,4′-dpyo (4,4′-dipyridyl N,N′-dioxide)) self-assemble to form three cluster-based 1D coordination polymers: [Mn(Salen)(MeOH)2]2{(4,4′-dpyo) [(Mn(Salen))2(Nb6Cl12(CN)6)]}·2MeOH (1), {(4,4′-bpe)[(Mn(7-MeSalen))2(Mn(7-MeSalen)(H2O))2(Nb6Cl12(CN)6)]}·1.5MeCN·8H2O (2), and [(4,4′-bpe)(Mn(Salen)(H2O))2]{(4,4′-bpe)2[(Mn(Salen)(MeOH))2(Mn(Salen))2(Nb6Cl12(CN)6)][(Mn(Salen))2(Nb6Cl12(CN)6)]}·16H2O (3). Single crystal X-ray diffraction analyses show that the frameworks of the three coordination polymers are built of heterotrimeric and/or heteropentameric supramolecular species linked by ditopic organic ligands. The framework of 1 consists of anionic chains built of heterotrimeric dianions [(Mn(Salen))2(Nb6Cl12(CN)6)]2− (T) linked by 4,4′-dpyo. The chains run along two directions ([0 2 −2] and [0 3 3]) leading to the formation of channels along the crystallographic (a) direction where the cations [Mn(Salen)(S)2]+ and solvent molecules are located. Also, 2 was reported earlier, it possesses a neutral 1D chain built of neutral heterpentameric supramolecules: [(Mn(7‐MeSalen))2(Mn(7‐MeSalen)(S))2(Nb6Cl12(CN)6)] (P) linked by 4,4′-bpe ligands. Hydrogen bonds between non-bridging cyanide ligands and coordinated solvent molecules connect the chains into 2D hydrogen-bonded frameworks. Finally, 3 features an anionic chain, built of alternating heterotrimers [(Mn(Salen))2(Nb6Cl12(CN)6)]2− and heteropentamers [(Mn(Salen)(S))2(Mn(Salen))2(Nb6Cl12(CN)6)] linked by the organic spacer 4,4′-bpe. The anionic charge is compensated by the in situe-assembled [Mn(Salen)(S)(4,4′‐bpe)Mn(Salen)(S)]2+ dimers. Magnetic measurements reveal that the Mn(III) ions are well isolated and only weak magnetic interactions are observed. The thermal stability of the three compounds was investigated.Jian-Jun Zhang, Sergio Aarón Gamboa, Barry Julian Davis, and Abdessadek Lachgar© 2010, Hindawi Publishing Corporation. All rights reserved.Process, Structure, and Properties of Electrospun Carbon Nanotube-Reinforced Nanocomposite Yarnshttp://www.hindawi.com/journals/amse/2009/868917.htmlCarbon nanotubes (CNTs) are dispersed into polyacrylonitrile polymer solution and then assembled into continuous nanocomposite yarns through the drum-tape co-electrospinning process to facilitate the translation of CNT properties to higher order structures. We explore the dispersion of CNTs in a polymer matrix, the process of obtaining continuous yarn through electrospinning, and the surface morphology and mechanical properties of the nanocomposite yarn.Nasir M. Uddin, Frank Ko, Jie Xiong, Bakhtier Farouk, and Franco Capaldi© 2010, Hindawi Publishing Corporation. All rights reserved.Synthesis and Surface Properties of Silica Spheres with Core Shell Structure by One Convenient Methodhttp://www.hindawi.com/journals/amse/2009/328508.htmlEarlier, we have published a paper on the preparation of silica sphere using propanol as cosurfactant. We report here a highly cost-effective method of preparation of mesoporous silica spheres with core shell structure using sodium silicate as silica precursor, cetyltrimethyl ammonium bromide (CTAB) as surfactant, and methanol as cosurfactant. Thus after removal of the template by dissolutions or/and activation at higher temperature, mesoporous silica spheres with core shell structure were obtained. The products prepared with methanol to CTAB molar ratio 8.5 : 1 were confirmed to give best results. All the spherical products have very large surface area (∼589–1044 m2/g), pore volume (∼0.98–1.41 cm3/g), and ordered pore structure.D. P. Das, K. M. Parida, and B. K. Mishra© 2010, Hindawi Publishing Corporation. All rights reserved.Polymer Light-Emitting Diodes Efficiency Dependence on Bipolar Charge Traps Concentrationhttp://www.hindawi.com/journals/amse/2009/503042.htmlThe efficiency of light-emitting diodes (LEDs) based on poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-1,4-benzo-{2,1′-3}-thiadiazole)], F8BT, is optimized upon simultaneous doping with a hole and an electron trapping molecule, namely, N,N′-Bis(3-methylphenyl)-N,N′-diphenylbenzidine and 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, respectively. It is shown that, for devices with poly(3,4-ethylene dioxythiophene) doped with polystyrene sulfonic acid as hole-injection layer material and magnesium cathodes, the efficiency is nearly doubled (from ca. 2.5 to 3.7 cd/A) upon doping with ca. 0.34% by weight of both compounds.Luis Morgado, Luis Alcácer, and Jorge Morgado© 2010, Hindawi Publishing Corporation. All rights reserved.Laser Beam Welding of AA5052, AA5083, and AA6061 Aluminum Alloyshttp://www.hindawi.com/journals/amse/2009/974182.htmlThe present investigation was mainly concerned with characteristics of autogeneous laser butt welding of 2 mm thickness nonheat treatable AA5052-H12, AA5083-H12 and 2 mm, 3 mm thickness heat treatable AA6061-T6 aluminum alloys. The effect of laser welding parameters, surface cleaning, filler wire addition, and backing strip on quality of laser welded joints was clarified using 5 kW CO2 laser machine. It was found that all the investigated alloys showed tendencies for porosity and solidification cracking, particularly, at high welding speed (≥4 m/min). Porosity was prevented by accurate cleaning of the base metal prior to welding and optimizing the flow rate of argon shielding gas. Solidification cracking was avoided through two different approaches. The first one is based on the addition of filler metal as reported in other research works. The other new approach is concerned with autogeneous welding using a backing strip from the same base metal, and this could be applicable in production. Preventing solidification cracking in both cases was related mainly to a considerable decrease in the stress concentration at the weld metal center as a result of improving the fusion zone profile. The implementation of the new approach could help in producing weldments with a better quality due to the absence of the filler metal, which is known as a source for hydrogen-related porosity. It can also have a positive economic aspect concerning the manufacturing cost since welding is done without the addition of filler metal. Not only quality and economic positive aspects could be achieved, but also high productivity is another feature since high quality autogeneous weldments were produced with high welding speed, 6 m/min. Hardness measurements and tensile test of AA6061 alloy welds indicated a remarkable softening of the fusion zone due to dissolution of the strengthening precipitates, and this was recovered by aging treatment after welding. For alloys AA5052 and AA5083, softening of the fusion zone due to the loss of its work-hardened condition was much less in comparison with AA6061 alloy.A. El-Batahgy and M. Kutsuna© 2010, Hindawi Publishing Corporation. All rights reserved.Application of Thermosensitive Peptide Copolymer Gels to Removal of Endocrine Disruptorhttp://www.hindawi.com/journals/amse/2009/597308.htmlPoly(L-leucine)-block-poly(ethylene glycol)-block-poly(L-leucine) triblock copolymers were synthesized by a ring-opening polymerization of α-amino acid N-carboxyanhydride with amino-terminated PEG as an initiator. The chloroform solution of these peptide copolymers showed a thermo-sensitive sol-gel transition. The transition temperature varied as a function of the length of peptide segments. Additionally, we used these peptide copolymers to remove an endocrine disruptor such as bisphenol A from its aqueous solution. As a result, it became clear that the peptide copolymer gel used in this study could capture bisphenol A efficiently.Satoshi Tanimoto, Naoto Yagi, and Hitoshi Yamaoka© 2010, Hindawi Publishing Corporation. All rights reserved.Cyclic Deformation Behavior and Fatigue Crack Propagation of Low Carbon Steel Prestrained in Tensionhttp://www.hindawi.com/journals/amse/2009/657284.htmlThe tests were performed on low carbon steel plate. In the tension fatigue tests, two angle values (ϕ=0° and ϕ=45°, ϕ is the angle between the loading and the rolling direction) have been chosen. The influence of strain path change on the subsequent initial work softening rate and the saturation stress has been investigated. Dislocation microstructure was observed by transmission electron microscopy. It was found that the strain amount of preloading in tension has obviously affected the cyclic softening phenomenon and the initial cyclic softening rate. It was observed that the reloading axial stress for ϕ=45° case increased more than that of ϕ=0° case, due to the anisotropism of Q235. In the fatigue crack propagation tests, the experimental results show that with increasing the pretension deformation degree, the fatigue crack growth rate increases, especially at the near threshold section.J. G. Wang, W. P. Jia, and D. Y. Ju© 2010, Hindawi Publishing Corporation. All rights reserved.Tribological Analysis of Mg2Si Particulates Reinforced Powder Metallurgy Magnesium Alloy Composites under Oil Lubrication Conditionhttp://www.hindawi.com/journals/amse/2009/628737.htmlFor the evaluation of wear behavior of Mg composites under oil lubrication conditions, powder metallurgy Mg97Y2Zn1 alloy reinforced with additive Mg2Si particles were fabricated by the repeated plastic working (RPW) and hot extrusion. The RPW process was effective in refining both Mg2Si reinforcements and α-Mg grains causing the matrix hardening. When increasing the repetition number of RPW process from 200 to 600 cycles, the particle size of Mg2Si additives changed from 8 μm to 1~2 μm, and α-Mg grain size was 1 μm or less. With regard to the defensive and offensive properties of Mg alloys reinforced with Mg2Si dispersoids, the composite had superior adhesive wear resistance compared with the conventional Mg alloys because of its extremely high microhardness of 95~180 Hv by RPW process. The uniform distribution of refined Mg2Si particles was useful for improving both defensive and offensive properties against AZ31B counter disk specimens. The Mg2Si prominent dispersoids in the matrix were also effective in forming the oil grooves around them, and caused the low and stable friction coefficient. On the other hand, in the case of the composite containing coarse Mg2Si particles, severely deep scratches were given on the counter face of the AZ31B disk, and resulted in an unstable and high friction coefficient.Katsuyoshi Kondoh, Junko Umeda, and Kenshi Kawabata© 2010, Hindawi Publishing Corporation. All rights reserved.Flow through a Two-Scale Porosity Materialhttp://www.hindawi.com/journals/amse/2009/701512.htmlFlow through a two-scale porous medium is here investigated by a unique comparison between simulations performed with computational fluid dynamics and the boundary element method with microparticle image velocimetry in model geometries.A. G. Andersson, L. G. Westerberg, T. D. Papathanasiou, and T. Staffan Lundström© 2010, Hindawi Publishing Corporation. All rights reserved.Characterizing Wool Keratinhttp://www.hindawi.com/journals/amse/2009/147175.htmlKeratin from wool is a reactive, biocompatible, and biodegradable material. As the biological structural component of skin (soft keratins) and of nails, claws, hair, horn, feathers, and scales (hard keratins) pure keratin comprises up to 90% by weight of wool. Wool was treated in alkaline solutions to extract from 68% to 82% keratin within 2 to 5 hours of exposure at 65∘C. The keratin products were water-soluble and were confirmed to contain intermediate filament and microfibrillar component-proteins of fractured, residual cuticle, and cortical cells. Oxidation of wool by peroxycarboximidic acid in alkaline hydrogen peroxide produced keratin products with distinct microcrystalline structures: descaled fibers, fibrous matrices, and lyophilized powders. Morphology and confirmation of peptide functionality were documented by SEM, Amino Acid Analysis, SDS-PAGE gel electrophoresis, MALDI-TOF/TOF, and FTIR analyses. The reactivity of keratin from wool models the reactivity of keratin from low-value sources such as cattle hair.Jeanette M. Cardamone, Alberto Nuñez, Rafael A. Garcia, and Mila Aldema-Ramos© 2010, Hindawi Publishing Corporation. All rights reserved.The Determination of Bound Water in Waste Phosphatic Clayhttp://www.hindawi.com/journals/amse/2009/854701.htmlPhosphatic clay is a by-product of phosphate strip mining, particularly in Florida, USA. This waste material occupies about 100 000 acres of land which could be utilized for other causes. Thus, its use as an alternating cementing material for the addition into the mixing matrix of cement paste and concrete to yield higher strength would be profitable for both materials involved. But the biggest drawback faced is that the phosphatic clay possesses high water holding capacity. The water is thus not available for mixing purposes when added to cement paste and concrete and is thus known as bound water. It is therefore essential to determine the amount of bound water to phosphatic clay which shall not be available for the hydration reaction of cement in cement paste and concrete.Mahir Dham, Bjorn Birgisson, and Andrew J. Boyd© 2010, Hindawi Publishing Corporation. All rights reserved.The Studies of Conditions for Inducing Chirality to Cu(II) Complexes by Chiral Zn(II) and Ni(II) Complexes with Schiff Basehttp://www.hindawi.com/journals/amse/2009/484172.htmlRecently, we have discovered that some chiral Schiff-base nickel(II) complexes induced d-d bands of CD spectra of some achiral copper(II) complexes. However, the novel phenomenon could be observed only a few systems of hybrid materials or limited conditions so far. In order to test conditions about copper(II) ions, we investigated model systems (1) metal-dendrimer (Cu-PAMAM; G4-NH2 terminal) containing relatively small amount of copper(II) ions (4.5 equivalent to PAMAM) for modeling separated systems of achiral copper(II) complex from chiral Schiff-base nickel(II) or zinc(II) complexes, Bis(N-R-1-naphtylethyl-3,5-dichlorosalicydenaminato)nickel(II) or zinc(II) by polymer matrix. (2) equilibrium of copper(II) N-ethylethylenediamine complexes to measure absorption spectra of d-d band, pH, and electron conductivity during titration of copper(II) ions. The results showed that (1) 4.5Cu-PAMAM could not be induced their d-d bands by the chiral nickel(II) or zinc(II) complexes, which suggested that separation by polymers prevented from inducing CD peaks. (2) Although 36Cu-PAMAM was known, uncoordinated copper(II) ions excess to ligands mainly attributed to increase electron conductivity by remained ions in methanol solutions, which was not associated with intermolecular interaction or dipole moments being effective for the induced CD mechanism by using molecular recognition between neutral molecules of metal complexes.Takashiro Akitsu, Jun Yamaguchi, Naoki Uchida, and Yoshikazu Aritake© 2010, Hindawi Publishing Corporation. All rights reserved.Prediction of Continuous Cooling Diagrams for the Precision Forged Tempering Steel 50CrMo4 by Means of Artificial Neural Networkshttp://www.hindawi.com/journals/amse/2009/582739.htmlQuenching and tempering of precision forged components using their forging heat leads to reduced process energy and shortens the usual process chains. To design such a process, neither the isothermal transformation diagrams (TTT) nor the continuous cooling transformation (CCT) diagrams from literature can be used to predict microstructural transformations during quenching since the latter diagrams are significantly influenced by previous deformations and process-related high austenitising temperatures. For this reason, deformation CCT diagrams for several tempering steels from previous works have been investigated taking into consideration the process conditions of precision forging. Within the scope of the present work, these diagrams are used as input data for predicting microstructural transformations by means of artificial neural networks. Several artificial neural network structures have been examined using the commercial software MATLAB. Predictors have been established with satisfactory capabilities for predicting CCT diagrams for different degrees of deformation within the analyzed range of data.Florian Nürnberger, Mirko Schaper, Friedrich-Wilhelm Bach, Iryna Mozgova, Kostjantyn Kuznetsov, Anna Halikova, and Olga Perederieieva© 2010, Hindawi Publishing Corporation. All rights reserved.Preparation and Characterization of a Calcium Carbonate Aerogelhttp://www.hindawi.com/journals/amse/2009/138476.htmlWe report on a facile method for the preparation of a calcium carbonate aerogel consisting of aggregated secondary vaterite particles with an approximate average diameter of 50 nm. It was synthesized via a sol-gel process by reacting calcium oxide with carbon dioxide in methanol and subsequent supercritical drying of the alcogel with carbon dioxide. The resulting monolith was opaque, brittle and had overall dimensions of 6×2×1 cm. It was characterized by X-ray powder diffraction, nitrogen adsorption method (BET), and scanning electron microscopy.Johann Plank, Heinz Hoffmann, Joachim Schölkopf, Wolfgang Seidl, Ingo Zeitler, and Zheng Zhang© 2010, Hindawi Publishing Corporation. All rights reserved.Fire and Gas Barrier Properties of Poly(styrene-co-acrylonitrile) Nanocomposites Using Polycaprolactone/Clay Nanohybrid Based-Masterbatchhttp://www.hindawi.com/journals/amse/2008/394235.htmlExfoliated nanocomposites are prepared by dispersion of poly(ε-caprolactone) (PCL) grafted montmorillonite nanohybrids used as masterbatches in poly(styrene-co-acrylonitrile) (SAN). The PCL-grafted clay nanohybrids with high inorganic content are synthesized by in situ intercalative ring-opening polymerization of ε-caprolactone between silicate layers organomodified by alkylammonium cations bearing two hydroxyl functions. The polymerization is initiated by tin alcoholate species derived from the exchange reaction of tin(II) bis(2-ethylhexanoate) with the hydroxyl groups borne by the ammonium cations that organomodified the clay. These highly filled PCL nanocomposites (25 wt% in inorganics) are dispersed as masterbatches in commercial poly(styrene-co-acrylonitrile) by melt blending. SAN-based nanocomposites containing 3 wt% of inorganics are accordingly prepared. The direct blend of SAN/organomodified clay is also prepared for sake of comparison. The clay dispersion is characterized by wide-angle X-ray diffraction (WAXD), atomic force microscopy (AFM), and solid state NMR spectroscopy measurements. The thermal properties are studied by thermogravimetric analysis. The flame retardancy and gas barrier resistance properties of nanocomposites are discussed both as a function of the clay dispersion and of the matrix/clay interaction.S. Benali, A. Olivier, P. Brocorens, L. Bonnaud, M. Alexandre, S. Bourbigot, <?layout cmd="newline"?> E. Espuche, F. Gouanve, R. Lazzaroni, and Ph. Dubois© 2010, Hindawi Publishing Corporation. All rights reserved.Morphological Investigation of Foamed Aluminum Parts Produced by Melt Gas Injectionhttp://www.hindawi.com/journals/amse/2009/506024.htmlPorous metal materials are a new class of materials with low densities, large specific surface, and novel physical and mechanical properties. Their applications are extremely varied: for light weight structural components, for filters and electrodes, and for shock or sound absorbing products. Recently, interesting foaming technology developments have proposed metallic foams as a valid commercial chance; foam manufacturing techniques include solid, liquid, or vapor state methods. The foams presented in this study are produced by Melt Gas Injection (MGI) process starting from melt aluminum. The aim of this investigation is to obtain complex foamed aluminum parts in order to make the MGI more flexible. This new method, called MGI-mould process, makes possible to produce 3D-shaped parts with complicated shape or configuration using some moulds obtained by traditional investment casting process.R. Surace, L. A. C. De Filippis, E. Niini, A. D. Ludovico, and J. Orkas© 2010, Hindawi Publishing Corporation. All rights reserved.Effects of Particle Size and Type of Alumina on the Morphology and Photoluminescence Properties of Sr4Al14O25:Eu2+/Dy3+ Phosphorhttp://www.hindawi.com/journals/amse/2009/475074.htmlSr4Al14O25:Eu2+/Dy3+ phosphor with high luminescence intensity and long afterglow duration was synthesized using 1.0 μm (α), 0.1 μm (α), and 0.05 μm (γ) particle sizes of Al2O3. SEM observation results showed that spike-like thin particles were formed when 0.05 μm γ-Al2O3 was used as raw material. Hexagonal thick particles were observed when 0.1 μm α-Al2O3 was used. But irregular, thin particles were observed while using 1 μm α-Al2O3. Photoluminescence measurements showed that both the initial intensity and the long persistency were much higher for the phosphor prepared using γ-Al2O3 of 0.05 μm particle size.Hom Nath Luitel, Takanori Watari, Toshio Torikai, and Mitsunori Yada© 2010, Hindawi Publishing Corporation. All rights reserved.