bluuebunny/crossref_metadata_2025_split huggingface dataset:
Air Independent Fuel Cells Utilizing Borohydride and Hydrogen Peroxide
Authors: Urian Richard Craig 
Published: March 2010

AbstractThe US Navy continues to pursue electrochemical power sources with high energy density for low rate, long endurance air independent, undersea applications. The use of borohydride and hydrogen peroxide as fuel and oxidant sources offer several different fuel cell configurations; each with their own advantages and technical challenges.The direct electro-oxidation and electro-reduction of sodium borohydride and hydrogen peroxide is conceptually a simple system. In the fuel cell configuration where Nafion 115 is used and both electrolyte solutions are allowed to have a pH >8, high efficiencies (>70%) can be maintained with careful control of the concentration of reactants in the flowing electrolyte, choice of catalyst and electrode architecture. The onset of borate precipitation is offset by diffusion of water created by the osmotic pressure between anode and cathode.The direct liquid/liquid system has the potential to be a “2V” system if the pH of the hydrogen peroxide catholyte is maintained at a pH<1. In order to make this a viable system for Naval applications, the amount of acid used in the catholyte to establish the desired pH needs to be minimized. The key enabling technology is the development of a suitable anion exchange membrane. The characteristics of the anion membrane are: 1) conduct hydroxides generated at the cathode to the anode in order to minimize its concentration buildup in the catholyte solution and to maintain the desired pH.<1, 2) minimize hydrogen peroxide cross-over and 3) afford high ionic conductivity.Efforts are currently underway to improve the understanding of the reaction mechanism of borohydride at the catalyst surface and to identify membranes with higher ionic conductivity. These efforts have been identified as critical paths for the successful development of a liquid/liquid borohydride/hydrogen peroxide fuel cell.
Scanning Force Microscopy Study of Phase Segregation in Fuel Cell Membrane Materials as a Function of Solvent Polarity and Relative Humidity
Authors: Hawley Marilyn , Kim Yu Seung , Hjelm Rex P. 
Published: March 2010

AbstractScanning force microscopy (SFM) phase imaging provides a powerful method for directly studying and comparing phase segregation in fuel cell membrane materials due to different preparation and under different temperature and humidity exposures. In this work, we explored two parameters that can influence phase segregation: the properties of the solvents used in casting membrane films and how these solvents alter phase segregation after exposure to boiling water as a function of time. SFM was used under ambient conditions to image phase segregation in Nafion samples prepared using five different solvents. Samples were then subjected to water vapor maintained at 100°C for periods ranging from 30 minutes to three hours and re-imaged using the same phase imaging conditions. SFM shows what appears to be an increase in phase segregation as a function of solvent polarity that changes as a function of water exposure.
Effects of Different Carbon Nanotube Supported Catalysts on Methanol and Ethanol Electro-Oxidation
Authors: Sanganna Gari Raghavendar Reddy , Li Zhou , Dong Lifeng 
Published: March 2010

AbstractIn this work, Pt and Pt-Ru nanoparticles were synthesized on both single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). Effects of different nanotube supports on electrocatalytic activity of Pt and Pt-Ru nanoparticles for methanol and ethanol oxidations were investigated using cyclic voltammetry and electrochemical impedance spectroscopy. In comparison to MWCNTs, SWCNT supported Pt and Pt-Ru catalysts demonstrate better electrocatalytic activities in terms of forward peak current density, the ratio of forward peak current density to reverse peak current density, and charge transfer resistance. This study indicates that SWCNTs can serve as effective catalyst supports for both direct methanol and ethanol fuel cells.
PdCo Nanoparticles Formation at HOPG and High Surface Area Carbon Support Vulcan XC-72R
Authors: Arroyo-Ramirez Lisandra , Miras Haralampos N , Raptis Raphael G , Cabrera Carlos Raul 
Published: March 2010

AbstractThermal reduction of PdCo molecular precursors may lead to the controlled production of nanoparticles on high surface area carbon supports that can be used as methanol tolerant oxygen reduction catalysts for direct methanol fuel cells (DMFC). Following this concept, a single molecular precursor source was used for the synthesis of bimetallic nanoparticles on highly oriented pyrolytic graphite (HOPG) and Vulcan (VC) carbon supports. Nanostructural formation of palladium-cobalt on highly ordered pyrolytic graphite (HOPG) was study by AFM, SEM and voltammetry. The relative humidity during precursor deposition was used to control the rings self-formation on HOPG surfaces. Palladium and palladium-cobalt nanoparticles were also formed on high surface area carbon support (Vulcan XC-72R) by thermal reduction and characterized by TEM. The Pd/VC and PdCo/VC nanoparticles were tested for the oxygen reduction reaction (ORR) with and without methanol. The Pd-based catalysts have ORR activity and high methanol tolerance.
Green Synthesis of Platinum-encapsulated Nickel Nanocatalyst and Its Microstructure Evaluation
Authors: Medina-Ramirez Iliana , Pan Xu-Bin , Bashir Sajid , Liu Jingbo Louise 
Published: March 2010

AbstractPlatinum (Pt) is the most efficient and highly utilized electrocatalsyt; however its high cost hinders its widespread use as a stand-alone catalyst. To remedy this problem, a nickel (Ni) encapsulated by Pt (NiⓔPt) nanocatalyst was fabricated using a cost-effective green colloidal method. The NiⓔPt nanoparticles (NPs) were then characterized using transmission electron microscope (TEM) equipped with X-ray energy dispersive spectroscopy (EDS), and X-ray powder diffraction (XRD) to determine the particle size distribution, morphology, elemental composition, and crystalline phase structure. The surface energetic was also measured using ZetaPALS™ to identify the stability of the colloidal suspension.
Investigation of Interaction of Hydrogen with Defects in Zirconia
Authors: Melikhova Oksana , Kuriplach Jan , Cizek Jakub , Prochazka Ivan , Brauer Gerhard , Anwand Wolfgang 
Published: March 2010

AbstractIn the present work we study theoretically hydrogen incorporated into several positions in the zirconia cubic and tetragonal lattices. These are positions in the interstitial space and in the zirconium vacancy (VZr). We examine the structure of such configurations and for VZr-related defects we also calculate selected positron characteristics in order to assess their capability of trapping positrons. It is shown that hydrogen atoms do not prefer to stay in the center of the largest interstitial space nor of VZr and they rather tend to create bonds with neighboring oxygen atoms. The positron lifetime of the VZr+1H complex is shorter than that for non-decorated VZr and positron trapping in VZr+1H complexes could, in principle, explain experimental lifetime data.
SURFACE SEGREGATION STUDIES OF SOFC CATHODES: COMBINING SOFT X-RAYS AND ELECTROCHEMICAL IMPEDENCE SPECTROSCOPY
Authors: Miara Lincoln , Piper Louis , Davis Jacob Nathan , Saraf Laxmikant , Kaspar Tiffany , Basu Soumendra , Smith Kevin E. , Pal Uday B. , Gopalan Srikanth 
Published: March 2010

AbstractA system to grow heteroepitaxial thin-films of solid oxide fuel cell (SOFC) cathodes on single crystal substrates was developed. The cathode composition investigated was 20% strontium-doped lanthanum manganite (LSM) grown by pulsed laser deposition (PLD) on single crystal (111) yttria-stabilized zirconia (YSZ) substrates. By combining electrochemical impedance spectroscopy (EIS) with x-ray photoemission spectroscopy (XPS) and x-ray absorption spectroscopy XAS measurements, we conclude that electrically driven cation migration away from the two-phase gas-cathode interface results in improved electrochemical performance. Our results provide support to the premise that the removal of surface passivating phases containing Sr2+ and Mn2+, which readily form at elevated temperatures even in O2 atmospheric pressures, is responsible for the improved cathodic performance upon application of a bias.
Liquid Encapsulation by Bonding-in-Liquid Technique
Authors: Okayama Yoshiyuki , Nakahara Keijiro , Ninomiya Takeshi , Matsumoto Yasuaki , Miki Norihisa 
Published: March 2010

AbstractWe propose and demonstrate Bonding-in-Solution Technique (BiST) for encapsulation of liquid in MEMS devices. Liquid encapsulation enables innovative MEMS devices with various functions, such as hydraulic displacement amplification and scanning mirrors. Interfusion of air bubbles and leakage of the encapsulated liquid must be averted not to deteriorate device performances. Several liquid encapsulation processes have been proposed, such as parylene deposition and polymer thermal bonding. However, they involve vacuum and/or thermal processes and cannot be applied to volatile liquids. In BiST, two structural layers are passively aligned and brought into contact in solution, where the encapsulation cavities are uniformly filled up with the liquid without air bubbles. A UV-curable resin is used as an adhesive that does not require heat or vacuum environment but UV to bond the two layers. The detail processes of BiST are (a)UV-curable adhesive resin is coated onto the bonding surface of a structural layer. The layer contains not only encapsulating cavities but also concave-shaped structures for the following passive alignment. (b) The other layer with convex-shaped structures is brought into contact in solution, when the two layers are passively aligned by matching concave and convex structures. (c) UV light is irradiated and the two layers are permanently bonded while the contact is maintained by the jig. We successfully achieved encapsulation of DI water and glycerin in PDMS and silicon structural layers. No liquid remains in the bonding interface. Since conventional aligners are not applicable to BiST, we experimentally evaluated the accuracy of the passive alignment process in solution that makes use of matching concave and convex structures. We used a PDMS layer with cylinders (concave) and a silicon layer with cavities (convex) to evaluate the alignment in BiST. The height and depth of the cylinders and cavities are designed such that the PDMS cylinders elastically deform when the two layers are brought into contact. The elastic averaging enables the passive alignment of the two layers. We investigated the bonding accuracy with respect to the number of pairs of concave/convex structures and the height of PDMS cylinders while in contact. The bonding accuracy improved as the number of pairs increased while the height of PDMS cylinders did not show a correlation. The alignment accuracy of 5μm in BiST was achieved with 12 pairs of the concave/convex structures. The ultimate goal of our research is to develop innovative MEMS devices with encapsulated liquid, such as a hydraulic displacement amplification mechanism applicable to a tactile display. Glycerin was encapsulated by largely-deformable-PDMS thin membranes and silicon cavities by using BiST. The displacement at the input was successfully amplified at the output associated with the ratio of the cross-sectional areas.
Extreme Phonon Softening in Laser-excited Bismuth – Towards an Inverse Peierls-transition
Authors: Lu Wei , Nicoul Matthieu , Shymanovich Uladzimir , Tarsevitch Alexander , Kammler Martin , Horn-von Hoegen Michael , von der Linde Dietrich , Sokolowski-Tinten Klaus 
Published: March 2010

AbstractLarge amplitude coherent optical phonons have been investigated in laser-excited Bismuth by means of femtosecond time-resolved X-ray diffraction. For absorbed laser fluences above 2 mJ/cm2, the experimental data reveal an extreme softening of the excited A1g-mode down to frequencies of about 1 THz, only 1/3 of the unperturbed A1g-frequency. At even stronger excitation the measured diffraction signals no longer exhibit an oscillatory behavior presenting strong indication that upon intense laser-excitation the Peierls-distortion, which defines the equilibrium structure of Bismuth, can be transiently reversed.
Ultrafast Tuning of Magnetization Precession and Magnetic Anisotropy in Thin Iron Films
Authors: Carpene Ettore , Mancini Eduardo , Dazzi Daniela , Dallera Claudia , Puppin Ezio , De Silvestri Sandro 
Published: March 2010

AbstractWe have developed an experimental set-up based on time-resolved Magneto-Optical Kerr Effect (MOKE) that allows to retrieve the vectorial magnetization dynamics in thin films with sub-picosecond resolution. This method has been exploited to measure the variations of the magnetization (modulus and orientation) induced by an ultrashort laser pulse. The initial demagnetization is established at the electronic level within a few hundreds of femtoseconds through electron-magnon excitations. The subsequent dynamics is characterized by a precessional motion on the 100 picosecond time-scale, around an effective, time-dependent field. Following the full dynamics of the magnetization, we have unambiguously determined the temporal evolution of the magneto-crystalline anisotropy, providing the clear experimental evidence that the precession is triggered by the rapid, optically-induced misalignment between the magnetization vector and the effective field. This method provides a simple and widely applicable way to study both magnetization and anisotropy in the sub-picosecond regime and therefore to unravel the mechanisms underlying the ultrafast evolution of the spin order in magnetic media.
Using a Low Cost Indentation Apparatus for the Study of Mechanical Properties of Thermoinsulating Materials and its Utilization in the Laboratory Practice of Students
Authors: Tsihouridis Charilaos A. , Polatoglou Hariton M. 
Published: March 2010

AbstractIn the present work we describe an experimental apparatus of very low cost , aiming at the experimental study of the mechanical properties of solid materials, using the method of indentation. The measurements allow, through a simple analysis, the quantitative determination of the materials' hardness and bulk modulus. A very important class of commonly used materials, namely thermoinsulating materials, is proposed for a case study. The method can furthermore be used to demonstrate the elastic and the plastic behavior of materials. The educational exploitation of the specific apparatus at a technical high school class in Larissa (Greece) and at a university physics students' laboratory practice on the subject of mechanical properties of materials are also described. The responses of the students on the whole process, and specifically on observations related to the pedagogical-educational aspects (active participation, challenge of interest, easiness of measurements, easiness of processing experimental data), as well as related to metrological aspects (uncertainty of measurements), were very positive and are also presented and discussed.
Academic/Industrial/NSF Collaborations at the IBM Almaden Research Center-Benefits from Dr. Marni Goldman's Involvement
Authors: Wade Charles G. , Miller Dolores C. , Black Kristin , Frank Curtis , Pesek Joseph 
Published: March 2010

AbstractCollege undergraduate and high school teacher internships are significant factors in materials science education. Traditionally, NSF-supported internships are done in academia. The NSF-supported academic/industrial internship programs involving Stanford University, San Jose University and the IBM Almaden Research Center extend the impact by the inclusion of an industrial research component. Internships through San Jose State University have existed since 1994 under a variety of NSF grants, most recently with NSF-REU support for undergraduate internships. Internships through Stanford university have existed since 1995 through an NSF Materials Research Science and Engineering Center, the “Center for Polymer Interfaces and Macromolecular Interfaces” (CPIMA). In these programs, the interns become members of an existing research group for 10 weeks and have their own project under a mentor. The interns attend a weekly seminar series on industrial research frontiers, a career day, a Graduate Record Examination workshop, a graduate school workshop, and tours of industrial research labs. Every participant presents a poster at an internal technical meeting at IBM at the end of the summer. For the industrial internships at IBM, the research is publishable but closely related to a technical area important to IBM. While the undergraduate and teacher internship programs are the major components of educational outreach of CPIMA, many other projects have been pursued, including public science, programs with local high schools, and science outreach to local community colleges. Dr. Marni Goldman was the Director of Educational Outreach for CPIMA from 2000 until her death in 2007, and she started many of the educational projects and programs. She was especially interested in diversity and initiated an internship program for students who are disabled. The programs will be reviewed and her contributions emphasized.
Introduction of Role Playing to a Research Ethics Module for the Undergraduate
Authors: Miller Dolores C. , Houle Frances A. , Stemwedel Janet , Pesek Joseph , Wade Charles 
Published: March 2010

AbstractAs part of the NSF supported SUMMIT (San Jose State University/IBM Almaden Research Center collaboration) REU and CPIMA (Stanford University/Almaden) SURE undergraduate internship programs we have developed a workshop that emphasizes the scientific community's dependence on ethical behavior for its success and advancement at this nascent stage of a scientific career. We have successfully introduced open-ended role playing based on recent real life ethics cases as reported in the scientific news to a foundation presentation based on the APS Ethics and Professional Conduct Guidelines for Physicists. The goal is to foster discussion of complex cases and their effects not only on the protagonists but on the scientific community.
A Novel Route for Preparation of Transparent and Superhydrophobic Silica Aerogels
Authors: Wu Guo-you , Cheng Xuan , Yu Yu-xi , Zhang Ying 
Published: March 2010

AbstractSilica aerogels were synthesized via sol-gel processing followed by a two-step surface modification and ambient pressure drying, using methyltrimethoxysilane (MTMS) and trimethylchlorosilane (TMCS)/ethanol/n-hexane as surface modification agents. The transparent silica aerogels possessed the porosities, densities and specific surface areas in the range of 87.7–92.3%, 0.27–0.17 g·cm-3 and 852–1005 m2·g-1, respectively. The SEM and HRTEM analysis revealed the three-dimensional nanoporous structure of the silica aerogels. The presence of –CH3 functional groups on the surface of silica particles as indicated by the FTIR spectra was further confirmed by two visible exothermic peaks at 310 and 450–500 °C from the DTA curve. In addition, the silica aerogels were superhydrophobic with the contact angle as high as 160°.
Marrow Stromal Cell Reponse to Fiber-Reinforced Laminated Nanocomposites
Authors: Ma Junyu , Xu Weijie , Jabbari Esmaiel 
Published: March 2010

AbstractCurrent biomaterials as a scaffold for bone regeneration are limited by the extent of degradation concurrent with bone formation, mechanical strength, and the extent of osteogenic differentiation of marrow stromal cells migrating from the surrounding tissues. In this project, a novel laminated nanocomposite scaffold is fabricated, consisting of poly (L-lactide ethylene oxide fumarate) (PLEOF) hydrogel reinforced with poly (L-lactide acid) (PLLA) electrospun nanofibers and hydroxyapatite (HA) nanoparticles. The laminated nanocomposites were fabricated by dry-hand lay up technique followed by compression molding and thermal crosslinking. The laminated nanocomposites were evaluated with respect to mechanical strength and osteogenic differentiation of marrow stromal (BMS) cells. Laminates showed modulus values much higher than that of hydrogel or fiber. The effect of laminated nanocomposites on osteogenic differentiation of BMS cells was determined in terms of ALPase activity and calcium content. Our results demonstrate that grafting RGD peptide to a PLEOF/HA hydrogel reinforced with PLLA nanofibers synergistically enhances osteogenic differentiation of BMS cells.
Terminal phosphate group influence on DNA - TiO2 nanoparticle interactions
Authors: Rice Zachary , Cady Nathaniel C , Bergkvist Magnus 
Published: March 2010

AbstractImmobilization of DNA/RNA, onto various metal and metal oxide surfaces is of great importance for the development of future microarray, gene mapping, DNA sequencing, nanoparticle targeting, and sensor applications. Attachment of DNA to solid interfaces typically occurs through either electrostatic interactions or covalent bonds to functional groups introduced to nucleic acid termini. Previously, we and others have demonstrated that alkanephosphates and terminal phosphate groups present on nucleic acids play an important role in the interaction with group IV metal oxides such as zirconium and hafnium, providing a stable linkage to the surface. Titanium dioxide (TiO2), which is frequently employed in various nanoscale applications, belongs to the same group and similar interactions with phosphate are expected. Various adsorption studies have demonstrated binding of nucleic acids to TiO2 surfaces, although the influence of terminal phosphate versus electrostatic interaction (via the DNA/RNA backbone) on the surface interaction is unclear. The research presented here investigates the effect of nucleic acid length, presence of terminal phosphates, and differences between dsDNA and ssDNA on their binding to TiO2 nanoparticles. TiO2 nanoparticles (20 nm) were used to study the adsorption of Lambda DNA (˜48 kbp), and shorter (21 bp) ssDNA and dsDNA oligonucleotides with and without a 5’ phosphate group. Initial adsorption of DNA to nanoparticles was calculated via UV absorption. Results showed that all types of nucleic acids (Lamda DNA, ssDNA and dsDNA) initially bind to nanoparticles, independent of molecular weight single/double strandedness, or phosphorylation state. The total amount of DNA initially adsorbed to nanoparticles (ng/particle) differs between ssDNA and dsDNA, as well as the length of the DNA used. These results show that nucleic acid interactions with TiO2 nanoparticles are not dependent upon the presence of a terminal phosphate group. These results provide valuable data for future applications based on DNA-nanoparticle constructs including nanoelectronics, photovoltaics, and biotemplated synthesis of semiconducting materials.
A Novel Bioactive Ceramic Coating for Improved Fixation of Orthopedic Implant
Authors: El-Ghannam Ahmed , . Aniket 
Published: March 2010

AbstractElectrophoretic deposition (EPD) coating of medical grade Ti-6Al-4V substrate with a novel silica-calcium phosphate nano-composite (SCPC) in the particle size range 50 nm-5 μm has been described. The influence of EPD parameters and thermal treatment on the coating homogeneity, thickness and adhesion strength has been studied. SEM analyses showed that EPD carried out in 5% (w/v) SCPC/ethanol suspension at 50 V produced a homogeneous coating on passivated Ti alloy discs. Tensile tests carried out to evaluate the adhesion strength at the ceramic/metal interface showed that the SCPC coating layer developed adhesion strength of 47 ± 4 MPa with Ti alloy after thermal treatment at 800 °C for 1 hr. SEM – EDX analyses of the fracture surface revealed that the presence of SCPC layer on the surface of the Ti alloy indicating high interfacial stability. Upon immersion of the SCPC-coated Ti alloy substrate in PBS, a surface biological hydroxyapatite layer was deposited suggesting bone bonding ability. The successful coating of SCPC on the Ti-6Al-4V has the potential to stimulate rapid fixation and lower stress shielding by enhancing the bone bonding ability of the implant.