bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alkaline anion‐exchange membranes for low‐temperature fuel cell application
Authors: Varcoe J. R. , Poynton S. D. , Slade R. C. T. 
Published: December 2010

AbstractThis review introduces alkaline anion‐exchange membranes (AAEM), the alkaline equivalents to the better known proton‐exchange membranes (PEM), their chemistries, and their applications in hydrogen solid alkaline fuel cells (SAFC). There has been a recent increase in understanding of AAEM behaviour in SAFCs; however, the field is still in its infancy compared to proton‐exchange membranes fuel cells (PEMFCs). Current AAEMs only exhibit adequate properties for application in SAFCs at higher humidities. Thinner AAEMs perform best due to facilitated supply of reactant water to the cathode oxygen reduction sites and reduced internal resistances. Further developments in alkaline ionomers are urgently required for high performance SAFCs.
Conductivity, permeability, and ohmic shorting of ionomeric membranes
Authors: Mittelsteadt C. K. , Liu H. 
Published: December 2010

AbstractTo minimize resistance losses, polymer electrolyte membranes are being fabricated thinner and with a higher acid content. This affects membrane resistance, gas permeability, and membrane durability. Models for the conductivity of perfluorinated sulfonic acid (PFSA) and sulfonated aromatic hydrocarbons are developed on the basis of the conductivity of small‐molecule analogues. These models are used to project an upper bound for conductivity of these systems. Gas permeability of PFSA membranes is modeled by separating transport into the hydrophobic and hydrophilic regions. Generally it is found that the gas permeability of PFSA materials is higher than that of hydrocarbon membranes. Two types of ohmic shorting tests are conducted on membranes of various thicknesses as well as membranes with an expanded poly(tetrafluoroethylene) support. Membranes with thickness above 90 μm do not short by these tests. For thinner membranes, both the addition of a catalyst layer and the poly(tetrafluoroethylene) support mitigates ohmic shorting.
Direct three‐dimensional visualization and morphological analysis of pt particles supported on carbon by transmission electron microtomography
Authors: Ito T. , Matsuwaki U. , Otsuka Y. , Katagiri G. , Kato M. , Matsubara K. , Aoyama Y. , Jinnai H. 
Published: December 2010

AbstractThe polymer fuel cell electrode (PFCE), consisting of platinum particles or platinum alloy particles supported on carbon particles and proton‐conducting ionomer binder, is one of the most important components in the fuel cell. The three‐dimensional (3‐D) imaging technique is important for the precise characterization of the carbon‐supported catalysts and the electrode. In this study, the Pt particles as the catalysts supported on different kinds of carbon particles were examined by transmission electron microtomography (TEMT) to obtain the first 3‐D structure of the carbon‐supported catalyst and to then evaluate the significant parameters that should allow characterization of the catalyst, i.e., the Pt nanoparticles supported on high‐surface area carbons. To obtain quantitative 3‐D images of the catalysts that contain extremely small Pt particles on the order of a few nanometers in diameter, a special sample preparation technique was developed for the TEMT experiments. As a result, the spatial resolution of ca 0.5 nm was achieved for the first time. On the basis of such very quantitative 3‐D images, a series of 3‐D image analysis algorithms were developed and used to evaluate significant structural parameters, e.g., the size and spatial distribution of the Pt particles on the carbon substrate, the “degree of embeddedness” of Pt into the carbon support, and the effective surface area of the catalyst per unit volume. These morphological parameters are useful in characterizing fuel cell catalysts and may be significant in studying the degradation mechanisms of catalysts during operation if they are examined before and after the operation.
Observation and modeling of thermal stresses in cells and cell stacks
Authors: Yakabe H. 
Published: December 2010

Abstract
Solid oxide fuel cells (SOFCs) are composed of ceramic components, and the mechanical reliability of cells is a serious subject in the development of SOFCs. In particular, the durability of the cell components against stresses during practical operations is an important problem. To evaluate the mechanical reliability of SOFCs, the magnitude of the stresses in cell components and the strength of the components against the stresses must be considered precisely. In this article, mechanical stresses in cells and cell stacks are evaluated experimentally and numerically.
Electrode degradation mechanisms studies by current distribution measurements
Authors: Carter R. N. , Gu W. , Brady B. , Yu P. T. , Subramanian K. , Gasteiger H. A. 
Published: December 2010

AbstractA technique is described for determining the source and degree of electrodes degradation in membrane electrode assemblies (MEAs) from proton exchange membrane fuel cells. This technique is nondestructive and provides spatial resolution across the MEA's active area. The degradation modes that are considered are the oxygen reduction activity loss through either electrochemically active area or mass activity loss, increased gas transport resistance from corrosion of the catalyst's carbon support, and the increased protonic transport loss through chemical degradation of the electrode layer's ion‐conducting polymer. A current distribution tool is used with cyclic voltammetry and polarization curves to isolate each of the primary sources of voltage degradation. Results of new MEAs are presented first to demonstrate the approximate resolution of the test method. Then results are presented for MEAs that were aged in a model test to cause carbon corrosion in the cathode layer via localized anode starvation. These include follow‐up materials characterization, where it is shown that the results of this electrochemical diagnostic correlate well with postmortem materials characterization. Finally, results are shown for a part aged in a model start‐up/shutdown aging test and compared with modeling results to explain the spatial characteristics of the observed degradation.
Methane reforming kinetics, carbon deposition, and redox durability ofNi/8 yttria‐stabilized zirconia (YSZ) anodes
Authors: Ivers‐Tiffée E. , Timmermann H. , Leonide A. , Menzler N. H. , Malzbender J. 
Published: December 2010

AbstractAnodes for stationary SOFC systems are most likely to be operated with natural gas at temperatures above 800 °C, whereas mobile SOFC applications such as APUs (auxiliary power units) operated below 800 °C use (liquid) hydrocarbons. The fuel (gasoline or diesel) cannot be converted by 100% in the reformer and so a reformate containing higher hydrocarbons has to be converted at the anode. In operation with hydrocarbons, at high fuel utilization or at sequential redox cycles, the nickel catalyst is subject to various degradation processes. The dominating process depends on the anodic oxygen partial pressure applied and possibly deteriorates the electrochemical performance of the anode.Sequential cyclic reduction and oxidation (redox) can quickly lead to an aging of the anode or even a complete failure of the cell (fracture of the thin film electrolyte). In operation with hydrocarbons, i.e., at low oxygen partial pressures, degradation ranging from (i) reversible damage by occupancy of the Ni catalyst surface with various deposits to (ii) irreversible damage to the Ni catalyst by carbon whisker growth occurs.Moreover, the kinetics of methane conversion under various operating conditions, the carbon formation in the presence of higher hydrocarbons (acetylene), and the analysis of electro‐oxidation and gas diffusion in stable operation with hydrogen or biomass‐derived gas are also treated in this article.
Ferromagnetism and Morphology of Annealed Fe2O3/CoXOY/ZnO Thin Films
Authors: Zolotaryov Andriy , Goetze Silvana , Bachmann Julien , Goerlitz Detlef , Hesse Dietrich , Nielsch Kornelius 
Published: December 2010

AbstractWe have studied thermal solid‐state reactions in the Fe2O3/CoXOY/ZnO thin film systems grown using the atomic layer deposition technique. The compound produced after annealing at 700 °C is found to be a complex mixture of three different spinel phases: ZnCo2O4, CoFe2O4, and ZnFe2O4. The magnetic properties of the compound strongly depend on the atomic ratio of Fe3+ and Co2+ atoms, which can be set by choosing the corresponding thicknesses of the Fe2O3 and CoXOY films. In addition, we also find a formation of 100 nm voids at the interface between Fe–Co–Zn–O compound and remaining ZnO film after 1h annealing at 700 °C in argon atmosphere. The formation of these voids shows indirectly the preferential outward diffusion of Zn2+ ions from ZnO into the Fe2CoO4 phase layer what we prove via our magnetic measurements.
Image Analysis of Endothelial Microstructure and Endothelial Cell Dimensions of Human Arteries – A Preliminary Study
Authors: Garipcan Bora , Maenz Stefan , Pham Tam , Settmacher Utz , Jandt Klaus D. , Zanow Jürgen , Bossert Jörg 
Published: December 2010

AbstractThe aim of this study was to broaden the relatively small number of qualitative and quantitative data available on the endothelium of human blood vessels by scanning electron microscopy (SEM) imaging and computer based image analysis of the human endothelial microstructure and dimensions. Endothelium of the arterial blood vessels (common iliac artery and hepatic artery) was imaged directly by using SEM. From high quality images, precise information on the microstructure and dimensions of endothelial cells was obtained by using GIMP and Leica QWin image analysis software. The mean endothelial cell width, length, and area of common iliac artery endothelial cells were found to be 13.2 ± 4.1 µm, 25.8 ± 8.5 µm, and 245.0 ± 115.1 µm2, respectively. For hepatic artery endothelial cells, mean values of cell width, length, and area were found to be 4.9 ± 1.5 µm, 21.9 ± 6.6 µm, and 70.7 ± 34.8 µm2, respectively. Morphology and dimension of the endothelial cells were different depending on the donor, type, and diameter of the arteries due to the effect of blood flow direction and volume rate. The presented method is useful for obtaining quantitative data on human endothelial cells. This study provides a first basis for future studies with larger numbers of samples on morphological changes secondary to pathological conditions, such as hypertension and atherosclerosis. Furthermore, the data may support the development of a template for a novel artificial vascular graft with superior performance.
Nanocomposite Elastomeric Biomaterials for Myocardial Tissue Engineering Using Embryonic Stem Cell‐derived Cardiomyocytes
Authors: Jawad Hedeer , El Fray Miroslawa , Boccaccini Aldo R. , Harding Sian E. , Wright Jamie S. , Chen Qizhi , Piegat Agnieszka , Ali Nadire N. 
Published: December 2010

AbstractRegeneration or repair of the damaged myocardium requires different strategies including engineered constructs for more efficient cell delivery. This study was undertaken to examine the potential of a new nanostructured elastomer to deliver embryonic stem cell‐derived cardiomyocytes (ESC‐CM) to an infarcted area of the myocardium. Engineered materials were biocompatible, mechanically stable, and elastomeric nanocomposites serving as substrates for delivery of ESC‐CM and as a left ventricular support device in myocardial regeneration strategies. Materials investigated were soft and strong poly(aliphatic/aromatic‐ester) multiblock thermoplastic elastomers with poly(ethylene terephthalate) (PET) hard segments and dimerized fatty acid, i.e., dilinoleic acid (DLA) soft segments, respectively, with and without addition of 0.2 wt% TiO2 nanoparticles to form nanocomposites. The PET/DLA‐TiO2 nanocomposite exhibited over 8 MPa tensile strength and 900% elongation at break. Addition of TiO2 nanoparticles significantly altered surface roughness and enhanced adhesion and spreading of ESC‐CM derived from mouse and human embryonic stem cells. The newly developed materials did not affect the functional activity of spontaneously beating hESC‐CM, as demonstrated by unaltered rate of their beating, and the cells continued to demonstrate contractile activity on the materials for more than two months in culture (the longest time tested). Quantitative proliferation and survival assays using fibroblasts confirmed the ability of the new materials to support cells as well as or better than the present commercial‐type thermoplastic elastomer analog. The results indicate that PET/DLA and PET/DLA‐TiO2 are promising candidates for the manufacture of engineered patches to deliver ESC‐CMs.
Organic D‐A‐π‐A Solar Cell Sensitizers with Improved Stability and Spectral Response
Authors: Zhu Weihong , Wu Yongzhen , Wang Shutao , Li Wenqin , Li Xin , Chen Jian , Wang Zhong‐sheng , Tian He 
Published: December 2010

AbstractA novel concept “D‐A‐π‐A” organic sensitizer instead of traditional D‐π‐A ones is proposed. Remarkably, the incorporated low bandgap, strong electron‐withdrawing unit of benzothiadiazole shows several favorable characteristics in the areas of light‐harvesting and efficiency: i) optimized energy levels, resulting in a large responsive range of wavelengths into NIR region; ii) a very small blue‐shift in the absorption peak on thin TiO2 films with respect to that in solution; iii) an improvement in the electron distribution of the donor unit to distinctly increase the photo‐stability of synthetic intermediates and final sensitizers. The stability and spectral response of indoline dye‐based DSSCs are improved by the strong electron‐withdrawing benzothiadizole unit in the conjugation bridge. The incident‐photon‐conversion efficiency of WS‐2 reaches nearly 850 nm with a power conversion efficiency as high as 8.7% in liquid electrolyte and 6.6% in ionic‐liquid electrolyte.
Investigation of the kinetics of fluidized bed spray agglomeration based on stochastic methods
Authors: Terrazas‐Velarde Korina , Peglow Mirko , Tsotsas Evangelos 
Published: December 2010

AbstractParticle formation during fluidized bed spray agglomeration is modeled by a Monte Carlo method. The methodology is based on the micromechanisms occurring within the bed. The most important model parameters are identified as interparticle collision time, deposited droplet drying time and droplet addition time. It is found that a high number of collisions leads to a negligible role of the drying mechanism. In the real bed, however, the process is dependent on the gas inlet temperature. This indicates that the number of collisions relevant to agglomeration is relatively low. The accordance of the model with experimental results for variations of several process parameters demonstrates that the approach is a promising way to simulate the formation of agglomerates. In addition, the model is able to reproduce slower agglomeration at increased temperatures. This result is, for the first time, based on physical mechanisms rather than on the use of fitted agglomeration kernels. © 2011 American Institute of Chemical Engineers AIChE J, 2011
Link between bubbling and segregation patterns in gas‐fluidized beds with continuous size distributions
Authors: Chew Jia Wei , Hrenya Christine M. 
Published: December 2010

AbstractExperiments involving a bubbling, gas‐fluidized bed with Gaussian and lognormal particle‐size distributions (PSDs) of Geldart Group B particles have been carried out, with a focus on bubble measurements. Previous work in the same systems indicated the degree of axial species segregation varies non‐monotonically with respect to the width of lognormal distributions. Given the widely accepted view of bubbles as “mixing agents,” the initial expectation was that bubble characteristics would be similarly non‐monotonic. Surprisingly, results show that measured bubble parameters (frequency, velocity, and chord length) increase monotonically with increasing width for all PSDs investigated. Closer inspection reveals a bubble‐less bottom region for the segregated systems, despite the bed being fully fluidized. More specifically, results indicate that, the larger the bubble‐less layer is, the more segregated the system becomes. The direct comparison between bubbling and segregation patterns performed provides a more complete physical picture of the link between the two phenomena. © 2011 American Institute of Chemical Engineers AIChE J, 2011
The incidence of thrombocytopenia in children with Cornelia de Lange syndrome
Authors: Lambert Michele P. , Jackson Laird G. , Clark Dinah , Kaur Mani , Krantz Ian D. , Deardorff Matthew A. 
Published: December 2010

AbstractThrombocytopenia was first reported in Cornelia de Lange syndrome (CdLS) by Froster in 1993. Despite early reports, thrombocytopenia has been rarely reported in this disorder. We performed a retrospective analysis of a large cohort of patients with CdLS. We calculated prevalence of thrombocytopenia in three subsets of this cohort: the entire cohort (n = 1,740), a subset of subjects with substantial clinical records (n = 695) and a subset of subjects with clinical information regarding platelet counts (n = 85). This analysis revealed that 15 have had thrombocytopenia (18% of those with available blood counts); seven had immune thrombocytopenia (ITP). The reported prevalence of pediatric ITP is between 5 and 13 per 100,000 persons. The prevalence of ITP in this cohort is between 7/1,740 and 7/85, giving a relative risk of ITP of between 30 (CI 12–77) and 633 (CI 259–1,549). Contrary to the reported cases in the literature, none of our patients have had progression of the thrombocytopenia nor have they developed other cytopenias. All 15 patients with thromobocytopenia had CdLS based on clinical criteria. Of the 10 patients tested for mutations in NIBPL, 8 had mutations identified. These data support an increased incidence of thrombocytopenia and ITP in CdLS. Subsequently, patients are at risk for spontaneous hemorrhage, and likely increased risk secondary to the high frequency of self‐injurious behavior. Although further studies are needed to better define the scope of the problem and to define the mechanisms of thrombocytopenia in CdLS, we would recommend screening for thrombocytopenia upon diagnosis and at 5‐year intervals thereafter. © 2010 Wiley‐Liss, Inc.
Dandy–Walker malformation associated with heterozygous ZIC1 and ZIC4 deletion: Report of a new patient
Authors: Tohyama Jun , Kato Mitsuhiro , Kawasaki Sari , Harada Naoki , Kawara Hiroki , Matsui Takeshi , Akasaka Noriyuki , Ohashi Tsukasa , Kobayashi Yu , Matsumoto Naomichi 
Published: December 2010

AbstractWe report on a female patient with Dandy–Walker malformation possibly caused by heterozygous loss of ZIC1 and ZIC4. The patient presented with mental retardation, epilepsy, and multiple congenital malformations including spina bifida, mild dysmorphic facial features including, thick eyebrows, broad nose, full lips, macroglossia, and hypoplasia of the cerebellar vermis with enlargement of the fourth ventricle on brain magnetic resonance imaging, which is consistent with Dandy–Walker malformation. A chromosome analysis showed interstitial deletion of chromosome 3q23‐q25.1. Fluorescence in situ hybridization (FISH) and microarray‐based genomic analysis revealed the heterozygous deletion of ZIC1 and ZIC4 loci on 3q24. Her facial features were not consistent with those observed in blepharophimosis–ptosis–epicanthus inversus syndrome (BPES) involving FOXL2 abnormality. Other deleted genes at 3q23‐25.1 might contribute to the dysmorphic facial appearance. A milder phenotype as the Dandy–Walker malformation in our patient supports the idea that modifying loci/genes can influence the development of cerebellar malformation. © 2010 Wiley‐Liss, Inc.
Sulfur removal from coal‐derived syngas: thermodynamic considerations and review
Authors: Dolan Michael D. , Ilyushechkin Alex Y. , McLennan Keith G. , Sharma Sunil. D. 
Published: December 2010

AbstractCurrent research into desulfurization sorbents for coal gasification is aimed at maximizing sorption capacity, kinetics and attrition resistance, while minimizing cost and volatility. Isolating the chemical aspects of desulfurization sorbent performance, however, is difficult because sorption performance is highly dependent on the physical form of the sorbent. To guide sorbent development, thermodynamic calculations offer a consistent basis from which to compare various aspects of sorbent performance, which includes conversion, but also speciation, volatility and regeneration. This approach has been used to compare 24 potential sorbents for the removal of sulfur from syngas, including oxides of transition metals, alkaline earths, alkalis and borates. Oxides of copper, manganese and zinc are most favourable for high‐temperature sulfur sorption and these oxides are chemically regenerable. The thermodynamic calculations are confirmed by the available literature, with the ZnO, MnO and CuO receiving the most attention in recent years. Each oxide has characteristic disadvantages, such as the tendency of copper oxide to reduce, the high volatility of zinc oxide and the high regeneration temperature of manganese oxide. This is driving the development of fabrication techniques which maximize sorbent dispersion, stability and tolerance to repeated sulfidation/regeneration cycles. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
Investigation on the correlation between rheology and morphology of PA6/ABS blends using ethylene acrylate terpolymer as compatibilizer
Authors: Mojarrad Alireza , Jahani Yousef , Barikani Mehdi 
Published: December 2010

AbstractPhase morphology and rheological behavior of polyamide 6 (PA6)/acrylonitrile butadiene styrene (ABS) polymers blends was studied using scanning electron microscopy and rheometry. The results showed that the phase morphology and rheological properties depends on blend composition. We evaluated the effect of addition of ABS as dispersed phase and EnBACO‐MAH (ethylene n‐butyl acrylate carbon monoxide maleic anhydride) as a compatibilizer on the morphological and rheological behaviors of PA6/ABS blends. It was concluded that there is a good agreement between the results obtained from rheological and morphological studies. As a consequence, addition of the ABS and compatibilizer weight percent led to a significant change in morphological structure and a great mounting in the viscosity as well as the elasticity. The rheological properties results demonstrate that adding compatibilizer to polymer blends led to increasing the crossover point, which shows a transition from a high viscous to a considerably more elastic behavior. Also, the slow transition of relaxation time peak from the peak of the PA6 to the peak of the ABS implies increasing the miscibility of the PA6/ABS blend components by increasing compatibilizer content. In addition, the Carreau–Yasuda model was used to extract information on rheological properties (zero shear viscosity and relaxation time) for PA6/ABS/EnBACO‐MAH blends by fitting the experimental data with this model. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011