http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2013 , Hindawi Publishing Corporation . All rights reserved. Tue, 14 May 2013 18:32:09 +0000 http://www.hindawi.com/isrn/ms/2013/270987/ Hyperbranched poly amide-ester (HBPAE) was synthesized by a solution condensation polymerization through one-step process using pentaerythritol as a central core and AB2 prepolymerized monomer which was rapidly prepared at room temperature (25°C) using commercially available maleic anhydride (MA) and diethanolamine (DEA) monomers in the presence of p-toluene sulfonic acid as a catalyst. The prepared polymer was characterized by GPC, IR, 1H-NMR, and thermal analysis (TGA and DSC). The influence of the polymer addition to the cement paste was investigated by measuring the effect of 1, 3 and 5 wt% HBPAE solutions on the properties of ordinary portland cement (OPC). Accordingly, several parameters were investigated such as water of consistency, setting times, bulk density, apparent porosity, compressive strength, and combined water content of the polymer/cement pastes. The SEM images proved that the incorporation of HBPAE with the OPC cement did not affect the chemical composition of hydrates, but it only affected the physical state, shape, size, morphology, and crystallinity of the formed hydrates. The results showed that the polymer addition to OPC pastes improved the physicomechanical properties of cement. Amal Amin Ibrahim, Ahmed El-Sayed Abdel-Megied, Mohamed Sayed Selim, Hassan Hassenen Darweesh, and Magdy Mohamed Ayoub Copyright © 2013 Amal Amin Ibrahim et al. All rights reserved. Thu, 09 May 2013 15:00:52 +0000 http://www.hindawi.com/isrn/ms/2013/938625/ This review highlights the use of the X-ray absorption spectroscopy (XAS) as a local structural tool for selected atoms in several host materials. The main characteristics of XAS to be element-sensitive and its applicability to all states of matter, including crystalline solids and amorphous and liquid states, permit an in-depth study of the structural properties of a large variety of materials. This includes intercalation materials where a host structure can accommodate guest species. Host guest equilibria are at the basis of a large variety of technological applications; in particular they have been used for energy storage, ion-exchange membranes, electrochromism, and analytical sensing. A selection of XAS experiments conducted in the field of batteries, mainly on cathodes, and applications in the field of metal hexacyanoferrates and double layered hydroxides are outlined. Marco Giorgetti Copyright © 2013 Marco Giorgetti. All rights reserved. Mon, 29 Apr 2013 13:16:55 +0000 http://www.hindawi.com/isrn/ms/2013/428624/ A sequential modeling effort for bistable composite laminates for piezoelectric morphing structures is presented. Thin unsymmetric carbon fiber composite laminates are examined for use of morphing structures using piezoelectric actuation. When cooling from the elevated cure temperature to room temperature, these unsymmetric composite laminates will deform. These postcure room temperature deformation shapes can be used as morphing structures. Applying a force to these deformed laminates will cause them to snap through to another shape. This bistability arises from the fabrication process of the thin unsymmetric laminates. The snap through force studied here will be controlled by using piezoelectricity. Macrofiber composite (MFC) actuators are used for piezoelectric actuation. In this research, an analytical modeling method is presented to accurately depict the piezoelectric morphing structures. Sequential numerical modeling of the cure process to account for residual stresses and postcured shapes and piezoelectric morphing structure is done to predict the piezoelectric actuated displacements of the thin unsymmetric composite laminates. Analytical and numerical models are compared to experimental methods and results. Darryl V. Murray and Oliver J. Myers Copyright © 2013 Darryl V. Murray and Oliver J. Myers. All rights reserved. Thu, 04 Apr 2013 16:14:58 +0000 http://www.hindawi.com/isrn/ms/2013/648246/ In this study, carbon steel sheets were coated with a modified epoxy coating. The urea-modified montmorillonite clay nanoparticles were added to a DGEBA epoxy resin in different contents and then applied to the surfaces. The corrosion resistance of the coated samples was determined by electrochemical techniques (open circuit potential and linear polarization) in 3.5 wt% NaCl solutions at room temperature and 80°C. Electrochemical impedance spectroscopy (EIS) evaluated the properties of polymer-coated metals and their changes during the exposure to corrosive environments. Scanning electron microscopy (SEM) was used to characterize the coatings. An improvement of protective properties of epoxy coatings with an optimal percentage of the modified clay in comparison with pure epoxy was achieved. Alisina Toloei, Sanam Atashin, and Mohammad Ebrahim Bahrololoom Copyright © 2013 Alisina Toloei et al. All rights reserved. Thu, 28 Mar 2013 17:24:48 +0000 http://www.hindawi.com/isrn/ms/2013/531093/ Three used PP-based car bumpers are characterized by many techniques (fractionation, IR, TGA, DSC, DMTA, and SEM). They show different impact and static and dynamic mechanical properties depending on their composition and morphology. It appears that block copolymer compatibilizers constituted by polyethylene-polypropylene sequences allow a better compatibility between the rubber domains and the PP matrix leading to relatively high impact resistance. Indeed if the ethylene sequences of the copolymer are large enough to crystallize, the decreased mobility of the whole system impairs the impact resistance. In addition, a higher amount of rubber in domains regular in shape and of greater dimension (1–3 μm) promotes a more homogeneous dispersion of external force inside the material, decreasing the risk of fracture. The amount of mineral fillers regulates the elastic modulus (the higher the load, the higher the modulus); however, a fairly good interfacial adhesion is required for satisfactory impact strength. All PP-based bumpers have been mechanically recycled in an internal mixer to redistribute oxidized species and to reestablish phase compatibilization. Recycling improves mechanical properties in slow speed test but fails to increase impact strength particularly in filled bumper, in which the quality of the matrix/filler interphase is hard to improve by simple remixing. M. P. Luda, V. Brunella, and D. Guaratto Copyright © 2013 M. P. Luda et al. All rights reserved. Wed, 27 Mar 2013 18:41:33 +0000 http://www.hindawi.com/isrn/ms/2013/231302/ Polycrystalline perovskite nanomaterials (Pb0.88La0.12)O3 were prepared by sol-gel reaction method. The crystal structure examined by X-ray powder diffraction indicates that the material was single phase with pseudocubic structure. EDX and SEM studies were carried out in order to evaluate the quality and purity of the compounds. The crystal symmetry, space group, and unit cell dimensions were determined from Cell-Ref software, whereas crystallite size was estimated from Scherrer’s formula. A correlation between grain size and diffuse character for the samples has been observed. Dielectric studies exhibit a diffuse phase transition characterized by a strong temperature and frequency dispersion of the permittivity and a relaxor behaviour. We have observed that dielectric constant decreases and ac conductivity increases with the frequency. The dielectric relaxation has been modeled using the Curie-Weiss and modified Curie-Weiss laws. The calculated activation energy for % and 3% was between 0.91–2.1 eV and 0.425–1.08 eV, respectively. The relaxation times were estimated from the Arrhenius law. Lhaj Hachemi Omari and Salaheddine Sayouri Copyright © 2013 Lhaj Hachemi Omari and Salaheddine Sayouri. All rights reserved. Wed, 20 Mar 2013 10:20:04 +0000 http://www.hindawi.com/isrn/ms/2013/682516/ The photoelectrochemical responses of a TiO2 nanotube anode in ethylene glycol (EG), glycerol, ammonia, ethanol, urea, and Na2S electrolytes with different concentrations were investigated. The TiO2 nanotube anode was highly efficient in photoelectrocatalysis in these solutions under UV light illumination. The photocurrent density is obviously affected by the concentration change. Na2S generated the highest photocurrent density at 0, 1, and 2 V bias voltages, but its concentration does not significantly affect the photocurrent density. Urea shows high open circuit voltage at proper concentration and low photocurrent at different concentrations. Externally applied bias voltage is also an important factor that changes the photoelectrochemical reaction process. In view of the open circuit voltage, EG, ammonia, and ethanol fuel cells show the trend that the open circuit voltage (OCV) increases with the increase of the concentration of the solutions. Glycerol has the highest OCV compared with others, and it deceases with the increase in the concentration because of the high viscosity. The OCV of the urea and Na2S solutions did not show obvious concentration effect. Kai Ren, Yong X. Gan, Efstratios Nikolaidis, Sharaf Al Sofyani, and Lihua Zhang Copyright © 2013 Kai Ren et al. All rights reserved. Thu, 07 Mar 2013 18:01:04 +0000 http://www.hindawi.com/isrn/ms/2013/147086/ This paper introduces a recent development and application of a noncommercial artificial neural network (ANN) simulator with graphical user interface (GUI) to assist in rapid data modeling and analysis in the engineering diffraction field. The real-time network training/simulation monitoring tool has been customized for the study of constitutive behavior of engineering materials, and it has improved data mining and forecasting capabilities of neural networks. This software has been used to train and simulate the finite element modeling (FEM) data for a fiber composite system, both forward and inverse. The forward neural network simulation precisely reduplicates FEM results several orders of magnitude faster than the slow original FEM. The inverse simulation is more challenging; yet, material parameters can be meaningfully determined with the aid of parameter sensitivity information. The simulator GUI also reveals that output node size for materials parameter and input normalization method for strain data are critical train conditions in inverse network. The successful use of ANN modeling and simulator GUI has been validated through engineering neutron diffraction experimental data by determining constitutive laws of the real fiber composite materials via a mathematically rigorous and physically meaningful parameter search process, once the networks are successfully trained from the FEM database. Hyuntae Na, Seung-Yub Lee, Ersan Üstündag, Sarah L. Ross, Halil Ceylan, and Kasthurirangan Gopalakrishnan Copyright © 2013 Hyuntae Na et al. All rights reserved. Thu, 07 Mar 2013 08:41:01 +0000 http://www.hindawi.com/isrn/ms/2013/649043/ The prime aim of this paper is to investigate, with the help of experiments, the induced anisotropy of mechanical properties in polycarbonate films. It is known that a molecular orientation in polymer materials occurs through cold-forming. In this study, cold forming is performed at room temperature on a tensile testing machine. The polycarbonate films are examined in two phases. In the first phase, the specimen is loaded, while the prestrain is varied, and in the second, it is loaded, while the material direction is varied. The main findings are that the prestrain has virtually no influence on the anisotropy and that the material direction does exert a major influence. Furthermore, this paper summarizes comparisons of anisotropic characteristic data, maximum stresses, elasticity moduli and failure strain. Andrea Wibbeke, Volker Schöeppner, and Rolf Mahnken Copyright © 2013 Andrea Wibbeke et al. All rights reserved. Wed, 06 Mar 2013 08:21:40 +0000 http://www.hindawi.com/isrn/ms/2013/187313/ A review is given of more than a dozen subtopics within the general study of ferroelectrics, with emphasis upon controversies, unsolved problems, and prospects for the next decade, including pure science and industrial applications. The review emphasizes work over the past two years, from 2010 to 2012. J. F. Scott Copyright © 2013 J. F. Scott. All rights reserved. Thu, 21 Feb 2013 14:41:26 +0000 http://www.hindawi.com/isrn/ms/2013/728195/ The structural and transport properties of manganites with and 0.2 prepared by solid state reaction route are studied. These compounds are found to be crystallized in orthorhombic structural form. A shift in the metal-semiconductor/insulator transition temperature () towards room temperature (289 K) with the substitution of Nd by La, as the value of is varied in the sequence (0, 0.1, and 0.2), has been provided. The shift in the , from 239 K (for ) to near the room temperature 289 K (for ), is attributed to the fact that the average radius of site-A increases with the percentage of La. The maximum temperature coefficients of resistance (TCR) of ( and 0.2) are found to be higher compared to its parent compound which is almost independent of . The electrical resistivity of the experimental results is explored by various theoretical models below and above . An appropriate enlightenment for the observed behavior is discussed in detail. Sudarshan Vadnala, Saket Asthana, Prem Pal, and S. Srinath Copyright © 2013 Sudarshan Vadnala et al. All rights reserved. Thu, 07 Feb 2013 13:12:07 +0000 http://www.hindawi.com/isrn/ms/2013/670130/ A potential major drawback with organic light-emitting devices, (OLEDs) is the limit of 25% singlet exciton production through spin-dependent charge recombination. Recent device results, however, show that this limit does not hold and far higher efficiencies can be achieved in purely fluorescent-based systems (Wohlgenannt et al. (2001), Dhoot et al. (2002), Lin et al. (2003), Wilson et al. (2001), Cao et al. (1999), Baldo et al. (1999), and Kim et al. (2000)). Thus, the question arises; is recombination spin dependent (Tandon et al. (2003)) or are singlet excitons generated in secondary processes? Direct measurement of the singlet generation rate in working devices of 44% has been shown (Rothe et al. (2006)), which have been verified as being part due to direct singlets formed on recombination and part from triplet fusion, singlets produced during triplet annihilation (Kondakov et al. (2009), King et al. (2011), and Zhang and Forrest (2012)). Here, the various routes by which triplet excitons can generate singlet states are discussed and their relative contributions to the overall electroluminescence yield are given. The materials requirements to obtain maximum singlet production from triplet states are discussed. These triplet contributions can give very high device yields for fluorescent emitters, which in the case of blue devices can be highly advantageous. Further, new devices architectures open up which are simple and have intrinsically low turn on voltages, ideal for large-area OLED lighting applications. A. P. Monkman Copyright © 2013 A. P. Monkman. All rights reserved. Sun, 03 Feb 2013 08:02:08 +0000 http://www.hindawi.com/isrn/ms/2013/173587/ This study represents an extension work to investigate the role of ultra fine sand (UFS) in enhancing the mechanical properties of fiber reinforced cementitious compounds. The micro-structural origins were identified by scanning electron microscope (SEM). About 50% of UFS had a diameter of less than 20 μm. Ordinary Portland Cement (OPC) was partially substituted by UFS at 3, 5, 7 and 10% by weight of binder. It was found that as UFS loadings increase, the flexural, compressive, and tensile strengths increased up to about 5% UFS loading by 12.9, 15.7 and 30.1%, respectively, thereafter, a decrease in these properties was observed. This can be attributed to the pozzolanic effect besides the filling effect of UFS resulting in enhancing the interfacial bonds between the sand grains and hydration products that makes the paste more homogeneous and dense. The effect of both short natural and artificial fiber loadings on the structural performance of compounds was also studied. Loadings of 2%, by weight, of short natural date palm leaves’ midribs fibers (DP) and artificial polypropylene fibers (PP) were added to the 5% UFS blended mix. An increase in both flexural and tensile strength was achieved, while a decrease in the compressive strength was observed. S. S. Shebl, Ibrahim S. Khalil, and H. Shoukry Copyright © 2013 S. S. Shebl et al. All rights reserved. Mon, 28 Jan 2013 08:39:14 +0000 http://www.hindawi.com/isrn/ms/2013/679820/ Semisolid metal processing (SSM) or thixoforming is a new technology that offers several advantages over liquid processing and solid processing. This process utilizes semisolid behavior as well as reduces macrosegregation, porosity, and forming forces during shaping process. A lot of research work has been carried out by various researchers in order to exploit the potential of this process to produce different products especially for automotive industry. This paper will summarise the rheological behavior of aluminium alloys in semisolid slurries, thixoformability of modified aluminium alloys, the effect of feedstock production method on mechanical properties, and the importance of developing low-cost raw materials for semisolid processing. M. S. Salleh, M. Z. Omar, J. Syarif, and M. N. Mohammed Copyright © 2013 M. S. Salleh et al. All rights reserved. Wed, 23 Jan 2013 07:17:50 +0000 http://www.hindawi.com/isrn/ms/2013/189659/ Morphing wing technologies provide expanded functionality in piloted and robotic aircraft, extending particular vehicle mission parameters as well as increasing the role of aviation in both military and civilian applications. However, realizing control surfaces that do not void the benefits of morphing wings presents challenges that can be addressed with microfiber composite actuators (MFCs). We present two approaches for realizing control surfaces. In one approach, flap-like structures are formed by bonding MFCs to each side of a metal substrate. In the other approach, MFCs are bonded directly to the wing. Counter intuitively, the flap approach resulted in larger voltage actuation curvatures, with increased mass load. Actuation performance, defined as the ratio of curvature per applied voltage, was as large as (kV·mm)−1. The direct bonding approach reveals that at zero wing pressure, up to  μm of displacement could be realized. Timothy D. Usher, Kenneth R. Ulibarri Jr., and Gilberto S. Camargo Copyright © 2013 Timothy D. Usher et al. All rights reserved. Thu, 17 Jan 2013 10:15:40 +0000 http://www.hindawi.com/isrn/ms/2013/637608/ The ion beam induced charge (IBIC) technique is a scanning microscopy technique which uses finely focused MeV ion beams as probes to measure and image the transport properties of semiconductor materials and devices. Its success stems from the combination of three main factors: the first is strictly technical and lies in the availability of laboratories and expertise around the world to provide scanning MeV ion beams focused down to submicrometer spots. The second reason stems from the peculiarity of MeV ion interaction with matter, due to the ability to penetrate tens of micrometers with reduced scattering and to excite a high number of free carriers to produce a measurable charge pulse from each incident ion. Last, but not least, is the availability of a robust theoretical model able to extract from the measurements all the parameters for an exhaustive characterization of the semiconductor. This paper is focused on these two latter issues, which are examined by reviewing the current status of IBIC by a comprehensive survey of the theoretical model and remarkable examples of IBIC applications and of ancillary techniques to the study of advanced semiconductor materials and devices. Ettore Vittone Copyright © 2013 Ettore Vittone. All rights reserved. Mon, 24 Dec 2012 11:52:41 +0000 http://www.hindawi.com/isrn/ms/2012/798247/ Polyethylenimine (PEI), considered as the most potent and promising alternative carrier to viral vectors, has been studied as the “state of the art” among various polymers for nonviral gene delivery applications for many years. Although PEI-based carrier minimizes the bottlenecks associated with viral vectors such as unwanted immunogenicity and production problems, the toxic side effects of PEI prevent its rapid advancements due to nondegradable nature. In this regard, various degradable cross-linking and/or grafting agents have been linked to synthesize degradable PEIs in order to minimize the toxicity and improve the efficacy of PEI-mediated gene carriers. This paper describes an update on various cross-linkers and grafting agents in the design and development of degradable PEI derivatives and their potential applications for effective delivery of DNA in vitro and in vivo. The molecular weight (MW) of PEI and the structural relationship to its cellular toxicity and transfection ability were also discussed. Finally, the potential applications of various degradable PEIs for small interfering RNA (siRNA)-mediated gene silencing were also covered. Chong-Su Cho Copyright © 2012 Chong-Su Cho. All rights reserved. Thu, 20 Dec 2012 16:37:20 +0000 http://www.hindawi.com/isrn/ms/2012/639520/ Safe long-term storage of radioactive waste from nuclear power plants is one of the main concerns for the nuclear industry as well as for governments in countries relying on electricity produced by nuclear power. A repository for spent nuclear fuel must be safe for extremely long time periods (at least 100 000 years). In order to ascertain the long-term safety of a repository, extensive safety analysis must be performed. One of the critical issues in a safety analysis is the long-term integrity of the barrier materials used in the repository. Ionizing radiation from the spent nuclear constitutes one of the many parameters that need to be accounted for. In this paper, the effects of ionizing radiation on the integrity of different materials used in a granitic deep geological repository for spent nuclear fuel designed according to the Swedish KBS-3 model are discussed. The discussion is primarily focused on radiation-induced processes at the interface between groundwater and solid materials. The materials that are discussed are the spent nuclear fuel (based on UO2), the copper-covered iron canister, and bentonite clay. The latter two constitute the engineered barriers of the repository. Mats Jonsson Copyright © 2012 Mats Jonsson. All rights reserved. Thu, 20 Dec 2012 09:50:00 +0000 http://www.hindawi.com/isrn/ms/2012/863025/ The possibility of using hydrogen as a reliable energy carrier for both stationary and mobile applications has gained renewed interest in recent years due to improvements in high temperature fuel cells and a reduction in hydrogen production costs. However, a number of challenges remain and new media are needed that are capable of safely storing hydrogen with high gravimetric and volumetric densities. Metal hydrides and complex metal hydrides offer some hope of overcoming these challenges; however, many of the high capacity “reversible” hydrides exhibit a large endothermic decomposition enthalpy making it difficult to release the hydrogen at low temperatures. On the other hand, the metastable hydrides are characterized by a low reaction enthalpy and a decomposition reaction that is thermodynamically favorable under ambient conditions. The rapid, low temperature hydrogen evolution rates that can be achieved with these materials offer much promise for mobile PEM fuel cell applications. However, a critical challenge exists to develop new methods to regenerate these hydrides directly from the reactants and hydrogen gas. This spotlight paper presents an overview of some of the metastable metal hydrides for hydrogen storage and a few new approaches being investigated to address the key challenges associated with these materials. Jason Graetz Copyright © 2012 Jason Graetz. All rights reserved. Tue, 04 Dec 2012 15:08:37 +0000 http://www.hindawi.com/isrn/ms/2012/513986/ This paper focuses on polymers that demonstrate microporosity without possessing a network of covalent bonds—the so-called polymers of intrinsic microporosity (PIM). PIMs combine solution processability and microporosity with structural diversity and have proven utility for making membranes and sensors. After a historical account of the development of PIMs, their synthesis is described along with a comprehensive review of the PIMs that have been prepared to date. The important methods of characterising intrinsic microporosity, such as gas absorption, are outlined and structure-property relationships explained. Finally, the applications of PIMs as sensors and membranes for gas and vapour separations, organic nanofiltration, and pervaporation are described. Neil B. McKeown Copyright © 2012 Neil B. McKeown. All rights reserved. Mon, 03 Dec 2012 16:09:51 +0000 http://www.hindawi.com/isrn/ms/2012/174803/ The study aimed at investigating the chemical composition and microstructure of raw iron ore from the deposits in Muko area (south-western Uganda). The quality of this iron ore was evaluated to establish its suitability to serve as a raw material for iron production. Samples were taken from the six hills of Muko ore deposits and tests carried out to establish their composition and properties. X-ray diffraction and scanning electron microscopy were employed in the investigation and chemical analysis performed to determine the compounds constituting the ore. The quality of this ore was compared to generalized world market standards and ores from other nations. It was found that Muko ore is a rich hematite grade with Fe content above 65%. It has little gangue (<6% SiO2 and 3-4% Al2O3) and low contents of the deleterious elements (% and %), which correspond to acceptable levels for commercial iron ores. Abraham J. B. Muwanguzi, Andrey V. Karasev, Joseph K. Byaruhanga, and Pär G. Jönsson Copyright © 2012 Abraham J. B. Muwanguzi et al. All rights reserved. Thu, 29 Nov 2012 14:22:42 +0000 http://www.hindawi.com/isrn/ms/2012/789525/ Recently, the direct synthesis of zeolitic materials has received much attention because several well-defined functionalities have been introduced in those materials by “one-pot” methodologies. The rationalization of the physics and chemistry of the processes involved in the zeolite growth has allowed the direct preparation of different functional molecular sieves with unique properties and potential applicability in industry. In the present paper, the “one-pot” preparations of metal-containing zeolites (both in framework and extra-framework positions), hybrid organic-inorganic molecular sieves, hierarchical microporous mesoporous zeotypes, nanosheets, nanozeolites, or template-free molecular sieves are intensively evaluated. Manuel Moliner Copyright © 2012 Manuel Moliner. All rights reserved. Wed, 21 Nov 2012 07:40:22 +0000 http://www.hindawi.com/isrn/ms/2012/746308/ This paper presents a literature review on fatigue in adhesively bonded joints and covers articles published in the Web of Science from 1975 until 2011. About 222 cited articles are presented and reviewed. The paper is divided into several related topics such as fatigue strength and lifetime analysis, fatigue crack initiation, fatigue crack propagation, fatigue durability, variable fatigue amplitude, impact fatigue, thermal fatigue, torsional fatigue, fatigue in hybrid adhesive joints, and nano-adhesives. The paper is concluded by highlighting the topics that drive future research. M. M. Abdel Wahab Copyright © 2012 M. M. Abdel Wahab. All rights reserved. Wed, 14 Nov 2012 10:21:16 +0000 http://www.hindawi.com/isrn/ms/2012/804763/ Using Fourier transform infrared (FTIR) spectroscopy analyses, we have studied the oxidation processes of methane or carbon monoxide in air-CH4 or air-CO flows interacting with polycrystalline catalytic oxides, as a function of temperature (T) and time (t). The gas flows crossed through La2O3, Lu2O3, CeO2, or Bi2O3 porous walls with constant composition and rate. The oxidation capacities of materials were determined from the intensities of CO2 vibrational bands resulting from the total oxidation of CH4 or CO into CO2. To interpret the time-dependent variations of these intensities, we have applied a model derived from Johnson-Mehl-Avrami approaches. This simple approach delivers pertinent parameters describing time-dependent oxidation rates. Bahcine Bakiz, Lamia Bourja, Abdeljalil Benlhachemi, Frederic Guinneton, Sylvie Villain, Mohamed Ezahri, and Jean-Raymond Gavarri Copyright © 2012 Bahcine Bakiz et al. All rights reserved. Wed, 14 Nov 2012 10:03:21 +0000 http://www.hindawi.com/isrn/ms/2012/719087/ Low-temperature phase BiTaO4 (α-BiTaO4) was successfully synthesized by the flux method using Bi2O3-B2O3 as the flux. According to previous reports, α-BiTaO4 has been mostly synthesized via a solid state reaction, which requires heating at 900°C for more than 48 h. In this study, α-BiTaO4 was successfully synthesized in 4 h at 750°C using the flux method. The impact of varying reaction conditions on the products was analyzed by X-ray diffraction and a scanning electron microscopy analysis. The grain size of α-BiTaO4 was dependent on reaction conditions such as the reaction temperature and solute concentration. The photocatalytic activity of the obtained α-BiTaO4 was evaluated for the degradation of phenol. It was found that flux-synthesized α-BiTaO4 exhibited a higher photocatalytic activity than α-BiTaO4 synthesized using the solid state method. Kohei Shimada, Chihiro Izawa, and Tomoaki Watanabe Copyright © 2012 Kohei Shimada et al. All rights reserved. Wed, 14 Nov 2012 09:31:08 +0000 http://www.hindawi.com/isrn/ms/2012/852905/ This paper summarizes the scientific trends associated with the rapid development of the technique of high-energy X-ray diffraction over the past decade pertaining to the field of liquids, glasses, and amorphous materials. The measurement of high-quality X-ray structure factors out to large momentum transfers leads to high-resolution pair distribution functions which can be directly compared to theory or combined with data from other experimental techniques. The advantages of combining highly penetrating radiation with low angle scattering are outlined together with the data analysis procedure and formalism. Also included are advances in high-energy synchrotron beamline instrumentation, sample environment equipment, and an overview of the role of simulation and modeling for interpreting data from disordered materials. Several examples of recent trends in glass and liquid research are described. Finally, directions for future research are considered within the context of past and current developments in the field. C. J. Benmore Copyright © 2012 C. J. Benmore. All rights reserved. Tue, 06 Nov 2012 08:14:17 +0000 http://www.hindawi.com/isrn/ms/2012/305692/ Most modern physics-based multiscale materials modeling and simulation tools aim to take into account the important details of the material internal structure at multiple length scales. However, they are extremely computationally expensive. In recent years, a novel data science enabled framework has been formulated for effective scale-bridging that is central to practical multiscaling. A salient feature of this new approach is its ability to capture heterogeneity of fields of interest at different length scales. In this approach, the computations at the mesoscale are handled using a novel data science approach called materials knowledge systems (MKS). The MKS approach has enjoyed tremendous success in building highly accurate and computationally efficient metamodels for localization (i.e., mesoscale spatial distribution of a macroscale imposed field such as stress or strain rate) in simulating a number of different multiscale materials phenomena. MKS derives its accuracy from the fact that it is calibrated to results from previously established numerical models for the phenomena of interest, while its computational efficiency comes from the use of fast Fourier transforms. The current capabilities and the future outlook for the MKS framework are expounded in this paper. Surya R. Kalidindi Copyright © 2012 Surya R. Kalidindi. All rights reserved. Tue, 16 Oct 2012 08:40:46 +0000 http://www.hindawi.com/isrn/ms/2012/129869/ Nanocomposites of polyaniline and zinc oxide nanoparticles using polycarbonate as supporting matrix were prepared by direct mixing process. These nanocomposites were studied for their DC electrical conductivity using four-in-line probe technique. Stability of DC electrical conductivity in terms of electrical conductivity retention was also studied using two slightly different techniques. The nanocomposites were also characterized using FTIR, SEM, TEM, and XRD. It was found that the electrical conductivity of the nanocomposites first increased with the increase in concentration of ZnO nanoparticles content, but then decreased on further increase in its content. Stability studies showed that the loss in electrical conductivity decreased with increase of ZnO content in nanocomposites. TEM and XRD results showed that nanoparticles are uniformly distributed in polymer matrix and also suggest that the direct solution mixing method may be adopted as an easy and efficient route for the preparation of nanocomposites. Shahid Pervez Ansari and Faiz Mohammad Copyright © 2012 Shahid Pervez Ansari and Faiz Mohammad. All rights reserved. Mon, 15 Oct 2012 09:36:42 +0000 http://www.hindawi.com/isrn/ms/2012/697056/ Information processors process information in a variety of ways. The human brain processes information through a highly interconnected system of neurons and synapses, while a digital computer processes information by having a binary switch toggle on and off in response to a stream of binary bits. The “switch” is the most primitive unit of the modern computer. The better it is (faster, more energy efficient, more reliable, etc.), the more advanced is the computer hardware. Energy efficiency, however, is more important than any other attribute, not so much because energy is costly, but because too much energy dissipation prevents increasing the density of switches on a chip that is necessary to make the chip increasingly more powerful. Reducing dissipation entails radically new and often revolutionary approaches for implementing the switch. One such approach is to encode digital bit information in the spin polarization of a single electron (or ensemble of electrons) and then using two mutually antiparallel polarizations to represent the binary bits 0 and 1. Switching between the bits can be accomplished by simply flipping the polarizations of the spins, which takes very little energy. Such switches are extremely energy efficient if designed properly, but they are somewhat slower than traditional transistor-based switches and can be more error prone. This paper discusses the pros and cons of spin-based switches and introduces the reader to the most recent advancements in information processing predicated on encoding information in electron spin polarization. Supriyo Bandyopadhyay Copyright © 2012 Supriyo Bandyopadhyay. All rights reserved. Sun, 30 Sep 2012 08:54:04 +0000 http://www.hindawi.com/isrn/ms/2012/945235/ A numerical finite difference method is developed here to solve the diffusion equation for hydrogen in presence of trapping sites. A feature of our software is that an optimization of diffusion and trapping parameters is achieved via a non linear least squares fit. On the other hand, we have demonstrated that usual electrochemical hydrogen permeation tests are enough to assess hydrogen free energies of trapping in the range of −35 kJ/mol to −70 kJ/mol. These conclusions are obtained by assuming the presence of saturable traps in local equilibrium with hydrogen and are validated by means of simulated permeation and degassing transients. In addition, we check our model performing electrochemical hydrogen permeation tests at 30°C, 50°C, and 70°C, on an API 5L X60 as received steel state to study its trapping and diffusion properties considering only one type of trapping site. The binding energies () and the trap densities () are determined by fitting the theoretical model to the experimental permeation data. The steel presents a high density of weak traps,  KJ/mol, namely,  mol cm−3. Strong trapping sites which alter the shape of the permeation transient are also detected; their values ranged from 57 to 72 KJ/mol. Patricia Castaño-Rivera, Viviana P. Ramunni, and Pablo Bruzzoni Copyright © 2012 Patricia Castaño-Rivera et al. All rights reserved.