bluuebunny/crossref_metadata_2025 huggingface dataset:
Prospective outcomes of injury study
Authors: Derrett S , Langley J , Hokowhitu B , Ameratunga S , Hansen P , Davie G , Wyeth E , Lilley R
Published: October 2009

Background:

In New Zealand (NZ), 20% of adults report a disability, of which one-third is caused by injury. No prospective epidemiological studies of predictors of disability following all-cause injury among New Zealanders have been undertaken. Internationally, studies have focused on a limited range of predictors or specific injuries. Although these studies provide useful insights, applicability to NZ is limited given the importance of NZ’s unique macro-social factors, such as NZ’s no-fault accident compensation and rehabilitation scheme, the Accident Compensation Corporation (ACC).

Objectives:

(1) To quantitatively determine the injury, rehabilitation, personal, social and economic factors leading to disability outcomes following injury in NZ. (2) To qualitatively explore experiences and perceptions of injury-related outcomes in face-to-face interviews with 15 Māori and 15 other New Zealanders, 6 and 12 months after injury.

Setting:

Four geographical regions within NZ.

Design:

Prospective cohort study with telephone interviews 1, 4 and 12 months after injury.

Participants:

2500 people (including 460 Māori), aged 18–64 years, randomly selected from ACC’s entitlement claims register (people likely to be off work for at least 1 week or equivalent).

Data:

Telephone interviews, electronic hospital and ACC injury data. Exposures include demographic, social, economic, work-related, health status, participation and/or environmental factors.

Outcome measures:

Primary: disability (including WHODAS II) and health-related quality of life (including EQ-5D). Secondary: participation (paid and unpaid activities), life satisfaction and costs.

Analysis:

Separate regression models will be developed for each of the outcomes. Repeated measures outcomes will be modelled using general estimating equation models and generalised linear mixed models.
PHENOMENOLOGICAL IMPLICATIONS OF A CLASS OF LEPTON MASS MATRICES
Authors: DEV S. , KUMAR SANJEEV , VERMA SURENDER , GUPTA SHIVANI
Published: October 2009

Phenomenological implications of a class of lepton mass matrices with parallel texture structure have been examined and phenomenologically interesting constraints on charged lepton and neutrino mass matrix parameters have been obtained.
WIGNER FUNCTIONS OF THERMO NUMBER STATE, PHOTON SUBTRACTED AND ADDED THERMO VACUUM STATE AT FINITE TEMPERATURE
Authors: HU LI-YUN , FAN HONG-YI
Published: October 2009

Based on Takahashi–Umezawa thermo field dynamics and the order-invariance of Weyl ordered operators under similar transformations, we present a new approach to derive the exact Wigner functions of thermo number state, photon subtracted and added thermo vacuum state. We find that these Wigner functions are related to the Gaussian–Laguerre type functions of temperature, whose statistical properties are then analyzed.
ASYMPTOTIC SAFETY IN HIGHER-DERIVATIVE GRAVITY
Authors: BENEDETTI DARIO , MACHADO PEDRO F. , SAUERESSIG FRANK
Published: October 2009

We study the nonperturbative renormalization group flow of higher-derivative gravity employing functional renormalization group techniques. The nonperturbative contributions to the β-functions shift the known perturbative ultraviolet fixed point into a nontrivial fixed point with three UV-attractive and one UV-repulsive eigendirections, consistent with the asymptotic safety conjecture of gravity. The implication of this transition on the unitarity problem, typically haunting higher-derivative gravity theories, is discussed.
STAR PRODUCT AND INTERACTING FIELDS ON κ-MINKOWSKI SPACE
Authors: KOWALSKI-GLIKMAN JERZY , WALKUS ADRIAN
Published: October 2009

In this note we extend the methods developed by Freidel et al.20 to derive the form of ϕ4 interaction term in the case of scalar field theory on κ-Minkowski space, defined in terms of star product. We present explicit expressions for the κ-Minkowski star product. Having obtained the the interaction term we use the resulting deformed conservation rules to investigate if they lead to any threshold anomaly, and we find that in the leading order they do not, as expected.
FABRICATION OF ALUMINUM MATRIX HYBRID NANOCOMPOSITE BY MECHANICAL MILLING
Authors: SHARIFI E. MOHAMMAD , KARIMZADEH F. , ENAYATI M. H.
Published: October 2009

Fabrication and characterization of aluminum matrix composite reinforced by Al 2 O 3– AlB 12 particles were investigated. Al 2 O 3– AlB 12 composite powder was first synthesized by mechanochemical route starting from Al and B 2 O 3 powder mixture. Then, prepared Al 2 O 3– AlB 12 powder was mixed with pure aluminum powder and ball milled in order to produce Al — 20 wt.% ( Al 2 O 3– AlB 12) composite. The structural evaluation of powders was studied by X-ray diffraction, scanning electron microscopy, and microhardness measurement. The results showed that through ball milling process a homogeneous distribution of Al 2 O 3– AlB 12 particles in nanocrystalline Al matrix was obtained. This structure exhibited good thermal stability and high hardness value of 190 HV which is significantly higher than 33 HV for pure Al .
UNUSUAL QUANTUM HALL EFFECTS, INDEX THEOREM AND SUPERSYMMETRY IN GRAPHENE
Authors: PARK K.-S. , YI K. S.
Published: October 2009

We exploit an index theorem and a high degree of symmetry to understand unusual quantum Hall effects of the n = 0 Landau level in graphene. The high symmetry such as the pseudospin symmetry of Fermi points in a graphene sheet cannot couple to an external magnetic field. In the absence of the magnetic field, the index theorem provides a relation between the zero-energy state of the graphene sheet and the topological deformation of the compact lattice. Under the topological deformation, the zero-energy state emerges naturally without the Zeeman splitting at the Fermi points in the graphene sheet. This results in the fact that the pseudospin is an exact symmetry. In the case of nonzero energy, the up-spin and down-spin states have the exact high symmetry of spin, forming the pseudospin singlet pairing. We describe the peculiar and unconventional quantum Hall effects of the n = 0 Landau level in graphene on the basis of the index theorem and the high degree of symmetry.
STRUCTURAL AND OPTICAL PROPERTIES OF γ-MO2N THIN FILMS DEPOSITED BY DC REACTIVE MAGNETRON SPUTTERING
Authors: ATUCHIN V. V. , KHASANOV T. , KOCHUBEY V. A. , POKROVSKY L. D. , GAVRILOVA T. A.
Published: October 2009

Molybdenum nitride films γ- Mo 2 N/Si have been fabricated with reactive magnetron sputtering in ( N 2 + Ar ) gas mixture. Phase composition of the films has been defined with reflection high energy electron diffraction. Refractive index and extinction coefficient of γ- Mo 2 N have been evaluated with laser ellipsometry at λ = 632.8 and 488.0 nm. Upper limit of γ- Mo 2 N film thickness measurable with laser ellipsometry has been found to be ~80 nm.
HIGHER-ORDER APPROXIMATIONS OF MOTION OF A NONLINEAR OSCILLATOR USING THE PARAMETER EXPANSION TECHNIQUE
Authors: GANJI S. S. , DOMAIRRY G. , DAVODI A. G. , BABAZADEH H. , SEYEDALIZADEH GANJI S. H.
Published: October 2009

The main objective of this paper is to apply the parameter expansion technique (a modified Lindstedt–Poincaré method) to calculate the first, second, and third-order approximations of motion of a nonlinear oscillator arising in rigid rod rocking back. The dynamics and frequency of motion of this nonlinear mechanical system are analyzed. A meticulous attention is carried out to the study of the introduced nonlinearity effects on the amplitudes of the oscillatory states and on the bifurcation structures. We examine the synchronization and the frequency of systems using both the strong and special method. Numerical simulations and computer's answers confirm and complement the results obtained by the analytical approach. The approach proposes a choice to overcome the difficulty of computing the periodic behavior of the oscillation problems in engineering. The solutions of this method are compared with the exact ones in order to validate the approach, and assess the accuracy of the solutions. In particular, APL-PM works well for the whole range of oscillation amplitudes and excellent agreement of the approximate frequency with the exact one has been demonstrated. The approximate period derived here is accurate and close to the exact solution. This method has a distinguished feature which makes it simple to use, and also it agrees with the exact solutions for various parameters.
ON THE MODELLING AND SIMULATION OF HIGH PRESSURE PROCESSES AND INACTIVATION OF ENZYMES IN FOOD ENGINEERING
Authors: INFANTE J. A. , IVORRA B. , RAMOS Á. M. , REY J. M.
Published: October 2009

High Pressure (HP) Processing has turned out to be very effective in prolonging the shelf life of some food. This paper deals with the modelling and simulation of the effect of the combination of high pressure and thermal treatments on food processing, focusing on the inactivation of certain enzymes. The behavior and stability of the proposed models are checked by various numerical examples. Furthermore, various simplified versions of these models are presented and compared with each other in terms of accuracy and computational time. The models developed in this paper provide a useful tool to design suitable industrial equipments and optimize the processes.
Effect of Gaseous Impurities on the Electrochemical Reduction of CO2 on Copper Electrodes
Authors: Zhai Yumei , Chiachiarelli Leo , Sridhar Narasi
Published: October 2009

Effects of impurities such as NO2 and SO2 with or without co-presence of O2 were studied in electrochemical reduction of CO2 on Cu in 0.5 M KHCO3 or 2 M KCl electrolyte in LS (liquid-solid) or GLS (gas-liquid-solid) cell. The effects of gaseous impurities are complex depending on geometry, flow rate, and speciation in solution. Generally, less than or equal to 1667 ppm of exposure NO2 is either beneficial or neutral - dissolved nitrate is beneficial, but nitrite and ammonia are detrimental. Less than or equal to 104 ppm of exposure of SO2 is either mildly detrimental or neutral - dissolved sulfide is extremely detrimental, but sulfate is beneficial. Oxygen can be detrimental (co-reductant or catalyst oxidant) or beneficial (oxidation of dissolved sulfide species) depending on LS or GLS geometry.
Electrochemical Oxidation of Carbon for Electric Power Generation: A Review
Authors: Cooper John F. , Selman Robert
Published: October 2009

Published research is reviewed for purposes of establishing baseline performance expectations for the direct conversion of carbon in a molten carbonate fuel cell. Examination of data from several sources supports the possibility of direct carbon conversion at a total efficiency of 80% (HHV) and peak power of at least 0.11 W/cm2 using atomically disordered carbon materials derived from fossil or biological sources The net anode reaction results in CO2 product at 0.1-0.2 V polarization, while parasitic corrosion of carbon by the reverse Boudouard reaction may be significant in parts of the carbon bed remote from the current collector. Also important are an understanding of the mechanism and extent of carbon wetting by the electrolyte. A cell configuration allowing simultaneous measurement of electrode potentials and off-gas composition is suggested for use in producing the data necessary for scale-up
Inorganic-organic ZnO Based Heterostructures for Lighting
Authors: Willander Magnus , Bano Nargis , Nur Omer
Published: October 2009

Here we present results on different organic and inorganic light emitting diodes (LED). The use of n-ZnO nanorods grown on different substrates forms the base of this new technology. p-type semiconducting as well as polymeric based substrates were used. The combination of n-ZnO nanorods and light emitting polymer(s) will lead to a LED with a broad emission spectrum and hence the possibility of producing white LEDs. Different issues regarding this hybrid new technology for lighting are to be discussed. Among them, we will present electrical, optical and electro-optical characteristics of different configurations of this hybrid technology regarding the polymer layer(s) choice. The light quality of the fabricated n-ZnO nanorods/p-type substrates LEDs will be shown and analyzed. Finally a comparison between this hybrid technology and other LEDs based on ZnO nanorods in combination with other inorganic p-type semiconductor is to be discussed.
New Statistical Figures of Merit for Color Quality of Solid-State Lamps
Authors: Zukauskas A. , Vaicekauskas Rimantas , Ivanauskas Feliksas , Vaitkevičius Henrikas , Vitta Pranciškus , Shur Michael
Published: October 2009

The existing color quality metric, which relies on color rendering indices, is in conflict with subjective rating of lamps based on light-emitting diodes (LEDs). To resolve the conflict, we introduce an approach, which relies on the statistical analysis of color shifts for a large number of color test samples. The analysis has shown that solid-state lamps have at least two distinct color rendering properties, namely, the color fidelity ability and color saturation ability. Using this approach, we performed optimization of trichromatic sources of light in terms of color fidelity ability or color saturation ability, or a trade-off between these two characteristics. In particular, the highest color fidelity index can be attained in phosphor-conversion LEDs with multiphospor blends or tetrachromatic or pentachromatic clusters of colored LEDs, whereas the highest color saturation index can be realized by using common trichromatic (red-green-blue) clusters.
Electrophoretic Deposition of YAG Phosphor on SMD LED
Authors: Chen Wen-Ray , Bai Jau-An , Meen Teen-Hang , Huang Chien-Jung
Published: October 2009

The uniform YAG phosphor layers were deposited onto the ITO glass substrates by electrophoretic deposition (EPD) technique. The more stable deposition condition was found when the electrolytic suspension was stirring. White SMD LEDs were easily achieved by using the directly EPD method, i.e. it is easy to achieve a white light point. For two white EPD LEDs, with and without thin epoxy layer, the chromaticity coordinates were x = 0.311, y = 0.29 and x = 0.311, y = 0.30, respectively. Although there has a uniform light shape for the EPD white LED with a thin epoxy layer, however, the lower luminescence efficiency was found due to the reduction of blue light extraction.
Thermal Buckling of Carbon Nanotubes
Authors: Lee Haw-Long , Chang Win-Jin , Fang Te-Hua
Published: October 2009

In this article, we analyze that the thermal buckling of single-walled carbon nanotubes (SWCNTs) and double-walled carbon nanotubes (DWCNTs) are subjected to axial compression due to temperature rise using Euler beam and Timoshenko beam theories. According to the analysis, the Euler beam model overpredicts the critical buckling temperature, especially at relatively small length-to-diameter ratios and higher-order modes. Therefore, the Timoshenko beam theory is able to predict the critical buckling temperature for SWCNTs and DWCNTs. In addition, the effects of rotary inertia and shear deformation on SWCNTs are larger than DWCNTs.
A Comparative Study on Electrochemical Properties of Nanocomposite Films Obtained by Co-Deposition of Conducting Polymers and Carbon Nanotubes
Authors: Branzoi Viorel , Branzoi Florina , Pilan Luisa N.
Published: October 2009

Composite films of carbon nanotubes with polypyrrole (PPY), polyaniline (PANI) and poly[o-phenylenediamine] (PoPD) were prepared via electrochemical co-deposition from solutions containing poly(m-aminobenzenesulfonic acid) functionalized single-walled carbon nanotubes (CNTs) and the corresponding monomer. The synthetic, morphological and electrochemical properties of PPY/CNTs, PANI/CNTs and PoPD/CNTs nanocomposites films were compared. Characterization was performed by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and scanning electron microscopy (SEM) techniques.
Electronic Properties of Carbon Nanotube Percolation Films and Nanotube Film-Semiconductor Junctions
Authors: Ural Ant
Published: October 2009

We show successful patterning of single-walled carbon nanotube (CNT) films down to 100 nm lateral dimensions and study their transport properties as a function of device dimensions. The results show that resistivity is independent of device length, while increasing over three orders of magnitude as device width and thickness shrink. We also investigate geometry-dependent resistivity scaling in CNT films using Monte Carlo simulations. These simulations can model and fit the experimental results and also determine the effect of parameters such as nanotube length and density on resistivity scaling trends. We also study the Schottky contact between CNT film and GaAs by fabricating and characterizing Metal-Semiconductor-Metal photodetectors with CNT film electrodes. We determine the mechanisms responsible for the transport and extract the Schottky barrier height of CNT film contacts. Furthermore, we compare the dark and photocurrent of the CNT film-based photodetectors with standard metal-based ones.
Single Walled Carbon Nanotubes Based Regulation of Proliferation and Diffeneration of Mouse Embryonic Stem Cells
Authors: Cui Daxiang , Wang Zheng , Zhang Hong , Ruan Jing , Bao Chengcheng , Yang Hao , Toru Asahi , Song Hua , Wang Kan
Published: October 2009

Carbon nanotubes'bio-effects have become a hotspot. In recent years, my group and collaborators try to use single walled carbon nanotubes(SWCNTs) as drug delivery system to regulate proliferation and differentiation of mouse stem cells. We observed that low dose of SWCNTs stimulate stem cells'proliferation and differentiation, higher dose of SWCNTs improve stem cells' apoptosis. Y-27632, a selective inhibitor of p160 Rho-associated coiled-coil kinase, can conjugate with SWCNTs and form the nanocomposites, which markedly inhibit the apoptosis of mouse stem cells, improve the proliferation and differentiation of stem cells. The potential mechanism of effects of Y-27632-SWCNT composites on stem cells is also dicussed. Our primary results suggest that special enzyme modified SWCNTs can be used to regulate proliferation and differentiation of stem cells, which has potential application in stem cells-based therapy.
Compounds I by Photo-Oxidation of Compounds II
Authors: Horner John H. , Sheng Xin , Chandrasena R. Esala P. , Zhang Rui , Wang Qin , Newcomb Martin
Published: October 2009

Photolysis of porphyrin iron(IV)-oxo species (Compounds II) with 366 nm light results in photo-ejection of an electron to give the corresponding iron(IV)-oxo porphyrin radical cations (Compounds I). Compounds I of the ubiquitous cytochrome P450 enzymes were produced by this method, and kinetics of reactions of P450 Compounds I were studied in real time.
CuCl-HCl Electrolyzer for Hydrogen Production via Cu-Cl Thermochemical Cycle
Authors: Gong Yanming , Chalkova Elena , Akinfiev Nikolay N. , Balashov Victor , Fedkin Mark , Lvov Serguei N.
Published: October 2009

The Cu-Cl thermochemical cycle is among the most attractive technologies proposed for hydrogen production due to moderate temperature requirements and high efficiency. In the present study, one of the main steps of the cycle - H2 gas production via CuCl-HCl electrolysis - was investigated using a newly designed electrolyzer system. The electrolysis reaction was performed with the applied voltage from 0.35 to 0.9 V. The current efficiency of the electrolysis system was evaluated based on the observed rate of hydrogen production. The effects of temperature and reagent flow rate on the electrolysis performance were studied. Several types of anion-exchange and cation-exchange membranes were tested in the electrolyzer, and their performance was compared with respect to process efficiency and tolerance to copper crossover.
Synthesis of Micro-Porous Boron-Substituted Carbon (B/C) Materials Using Polymeric Precursors for Hydrogen Physisorption
Authors: Chung T. C. Mike , Jeong Youmi , Kleinhammes Alfred , Wu Yue
Published: October 2009

This paper discusses a novel route to prepare porous boron substituted carbon (B/C) materials that show a significantly higher hydrogen binding energy and physisorption capacity, compared with the corresponding carbonaceous (C) materials. The chemistry involves a designed boron-containing polymeric precursor, which is the polycondensation adducts between BCl3 and lithiated phenylene diacetylene. During pyrolysis, most of the boron moieties in the precursor were transformed into a B-substituted C fused ring structure, and the in situ formed LiCl by-products created a porous morphology. The resulting porous B/C material with 7% B content and 700 m2/g surface area has been prepared, which shows a reversible hydrogen physisorption capacity of 0.6 and 3.2 wt% at 293 and 77 K, respectively, under 40 bars hydrogen pressure. The physisorption results were further warranted by absorption isotherms and in situ 1H NMR studies, indicating a binding energy of hydrogen molecules of about 11 kJ/mole, significantly higher than the 4 kJ/mole reported on most C surfaces
Hydrogen Generation from Alkaline Solutions of Methanol and Ethanol by Electrolysis
Authors: Ulusoy Isılay , Uzunoglu Aytekin , Ata Ali , Ozturk Osman , Ider Muhsin
Published: October 2009

In this study, electrolysis of alkaline methanol and ethanol solutions was carried out on platinized electrodes in actual cells with different cell preparation and catalyst coating methods. The electrolysis reaction products were analyzed by X-Ray and titrimetric methods. The gas phase products were analyzed by Gas Chromatography technique. Thermodynamic calculations and analysis results suggest that the carbonate formation is highly favorable in alkaline KOH solutions. However, methane formation reaction along with carbonate and oxygen formations may be possible during ethanol electrolysis. Alkaline methanol solutions were electrolyzed easily using platinum coated carbon paper electrodes. It was found that Nafion based MEA's are not essential for electrolysis of alkaline solutions of methanol and ethanol. One of the best performances was obtained using micro porous polyethersulfone membranes in a special cell configuration.
Hydrogen Evolution, Diffusion and Solution in Ni / Based Composite Electrodeposits
Authors: Mirkova Lidia , Monev Milko , Petkova Nicolina
Published: October 2009

Nickel electrodes are widely used in industrial water electrolysis cells for electrochemical production of hydrogen, as well as for battery applications. The use of Ni/based composites instead of pure Ni is one of the methods to enhance the electrocatalytic activity of Ni electrode material. In this paper, composite Ni /TiO2 layers were electrodeposited from a conventional Watts' electrolyte containing TiO2 powder, and their electrochemical properties towards hydrogen evolution reaction were investigated and compared with pure Ni layers under the same conditions. The composite layers are characterized by enhanced electrochemical activity with respect to hydrogen evolution reaction in an alkaline electrolyte - they feature a higher hydrogen evolution rate, as well as a lower overpotential as compared with pure Ni layers. The increased activity of Ni/ TiO2 composite layers could be related with the developed and increased electrode surface, as well as well as with the presence of Ti, incorporated in the Ni matrix. In addition, Ni/TiO2 layers show faster and more extensive hydrogenation than pure Ni deposits.
Measurements of Effective Oxygen Diffusivity, Pore Size Distribution, and Porosity in PEM Fuel Cell Electrodes
Authors: Yu Zhiqiang , Carter Robert
Published: October 2009

This paper presents the measurement results of effective oxygen diffusivity (DO2), pore size distribution, and porosity of proton exchange membrane fuel cell (PEMFC) electrodes, and the calculated tortuosities using these measurement results. A novel method has been developed to directly measure effective oxygen diffusivity in electrodes as a function of temperature and relative humidity (RH) on a conventional PEMFC platform with 50 cm2 flow fields. The pore size distributions and porosities of catalyst powder and electrodes are measured by nitrogen adsorption with the BJH model and mercury intrusion porosimetry (MIP). The measured porosities from the MIP results are considerably less than those calculated from material densities, suggesting that ionomer blocks some pores in electrodes. The calculated tortuosities are larger than those predicted by Bruggeman correction, indicating the Bruggeman correction underestimates the tortuosity and thus overestimate effective DO2 in PEMFC electrodes.
Preparation and Characterization of DMFC Electrodes and MEAs
Authors: Xue Xinzhong , Bock Christina , MacDougall Barry , Kingston David
Published: October 2009

A stencil method, that utilizes a dried powder made of the catalyst and the Nafion ionomer phase, is used to make catalyst layers and membrane electrode assemblies (MEAs). The influence of different hot-pressing conditions on the DMFC performance and various properties of the MEAs, in particularly on the properties of the anode, are investigated and compared to MEAs made by the conventional spray method. The highest DMFC performance is achieved using MEAs made by stenciling. It is also found that the membrane resistance (Rm), the resistance to proton transport within the catalyst layer (Rp) and the charge transfer resistance (Rct) towards the CH3OH oxidation reaction are lower for stenciled vs. sprayed anodes.
Spatiotemporal Behavior of Water and Two-Phase Transport in the Porous Electrodes for PEM Fuel Cells
Authors: Gurau Vladimir , Zawodzinski Thomas , Mann J. Adin
Published: October 2009

We analyze the impact of the interfacial phenomena at the macroscopic interfaces between fuel cell components on the water management and on the two-phase transport in proton exchange membrane fuel cell (PEMFC) electrodes using multiphase multi-fluid computational fluid dynamics (CFD). We present the numerical approach used to capture multiphase phenomena at the cathode gas diffusion layer (GDL) - channel interface and explain the mechanisms that trigger the phenomenon referred to as the eruptive water ejection. Notwithstanding that they have been widely ignored, these are phenomena which ultimately control the amount of water that reside in the fuel cell components during operation.
Analysis of Water Transport in Catalyst Layers
Authors: Sato Kazuyuki , Ohma Atsushi , Yamaguchi Koichi , Shinohara Kazuhiko
Published: October 2009

Water transport phenomena in catalyst layers (CLs) of a polymer electrolyte fuel cell were investigated experimentally and analytically. An experimental technique was developed for evaluating water transport resistance in the CLs based on the water permeation rate through the membrane electrode assembly (MEA). Water transport resistance in the CLs was regarded as being driven by the water activity gradient and was examined for MEAs with different CL thicknesses using an equivalent circuit model. This model consists of three transport mechanisms--vapor transport in pores, liquid transport in the ionomer and the phase change at the interface between the ionomer and pores. Experimental results showed that MEA resistance increased almost linearly with increasing CL thickness. Compared with the results calculated with the model, the phase change resistance was deemed to be negligibly small under our test conditions.
Characterization of SOFC Electrode Microstructure Using Nano-Scale X-ray Computed Tomography and Focused Ion Beam Techniques: a Comparative Study
Authors: Shearing Paul R. , Gelb Jeff , Brandon Nigel
Published: October 2009

In solid oxide fuel cells (SOFC) the redox reactions are supported by composite porous materials and, therefore, the electrochemical activity of an electrode is a direct function of its microstructure. Ni-YSZ (Yttria Stabilized Zirconia) is a common choice for the anode material in SOFC. Recently advances in tomographic techniques have enabled researchers to probe electrode microstructures providing unprecedented access to a wealth of microstructural information regarding the distribution of ionic, electronic and pore phases in three dimensions. In this paper nano-scale X-ray Computed Tomography (nCT) and Focused Ion Beam (FIB) techniques have been used to characterize microstructures from the same Ni-YSZ anode sample, 3D reconstruction from both techniques are presented and a quantitative and qualitative comparison is provided. An advanced technique for sample preparation for nCT is also presented.
Biocompatible Micellar Environment for Enzyme Encapsulation for Bioelectrocatalysis Applications
Authors: Sjoholm Kyle , Cooney Michael , Minteer S.
Published: October 2009

Chitosan, a biopolymer extracted from chitin, was deacetylated by treatment with 45% NaOH followed by autoclaving at 121oC for a period of 20 minutes. The deacetylated chitosan was then hydrophobically modified via reductive amination with sodium cyanoborohydride and butanal. Glucose dehydrogenase was then co-cast with each polymer on glassy carbon rotating disk electrodes and analysis of mass transfer was executed. Amperometric concentration studies were also carried out to determine catalytic activity of the glucose dehydrogenase enzyme system. The diffusion coefficient governing transport through the air dried film was measured to be 1.42×10-7 cm2/s and 1.08×10-7 cm2/s for butyl modified chitosan and butyl modified deacetylated chitosan, respectively.
Synthesis of Novel Electrode Materials Using Supercritical Fluids
Authors: Smirnova Alevtina L. , Hu Yan-Ling , Zhang Lichun , Aindow Mark , Menard Pete , Singh Pabhakar , Goberman Daniel , Shaw Leon , Wan Xuefei , Rhine Wendell
Published: October 2009

Supercritical carbon dioxide (scCO2) fluid has been used for synthesis of porous carbon aerogel (CA) support and CA supported catalysts, such as Pt, Ir, and Co single phase and PtIr binary and PtIrCo ternary catalysts. The CA synthesized from resorcinol-formaldehyde (RF) xerogel demonstrated a narrow pore size distribution (9.8{plus minus}0.5nm) and a surface area of 648m2/g. The TEM data indicates that the size of the metal and metal alloy nanoparticles deposited from the organometallic precursors varies in the range of 1-10nm depending on the metal or metal alloy and the corresponding organometallic precursor. The XPS data show a complicated nature of the interactions between metal nanoparticles and CA support. The electrochemical surface area calculated from the rotating disk electrode (RDE) measurements is in the range of 50-80cm2/g.The oxygen reduction kinetics evaluated by RDE confirms high catalytic activity of the synthesized materials.
Structural and Magnetic Properties of Different Shape Gold Nanoparticles
Authors: Meen Teen-Hang , Ciou Wan-Ci , Chao Shi-Mian , Liu Yu-Sung , Fang Te-Hua , Ho C. T. , Huang Chien-Jung
Published: October 2009

In this study, different shape of gold nanoparticles were prepared by seed-mediate growth method and investigated by the measurements of ultraviolet-visible (UV/Vis) spectrometer, transmission electron microscopy (TEM), X-ray diffractometer (XRD), and superconducting quantum interference device (SQUID). When the dosage of gold seed (DGS) is smaller than 0.03 mL or greater than 0.03 mL, the aspect ratio of gold nanorods will diminish, and the output of gold nanoparticles will also decrease. Therefore the optional condition for preparation of gold nanorod is DGS=0.03 mL. While DGS increases to 0.5 mL, the shape of the gold nanoparticles is changed form rod to sphere. There are weak ferromagnetism observed in the results of magnetization for gold nanorods and spherical nanoparticles under -2000 to 2000 Oe at 5K, and the coercive fields are 226 Oe and 66 Oe for the gold nanorods and spherical gold nanoparticles, respectively.
Fabrication and Application of Copper Nano Doughnut with Electro-plating Method on Patterned Nickel Template
Authors: Wu Shich-Chuan , Huang Wen-Hsien , Tsai Chuan-Mei
Published: October 2009

The nano Doughnut-like Copper periodic structure is fabricated by an electro-plating method on patterned Ni template. The diameter of the cover Cu doughnut hole can be controlled by a plating duration. This structure can be applied in a biosensor due to surface plasmonic resonance, and for novel optical device with variable hole diameter and period of that array. The Magnetic Force Microscope (MFM) was used for evaluating the bio-sensing response under the addition of magnetic proteins (metallothionein- MT, Mn2Cd5 Metallothionein-MMT, and Ferritin) on that sample before and after magnetization. In addition, the optical properties before and after magnetization were measured and scanned by Fourier transform infrared spectroscopy (FTIR). It is noted that some interesting behavior were observed in the spectra and transmitting ratio under different polarization incident conditions.
Synthesis and Dispersion of Copper Nanoparticles in Lubricant Oils
Authors: Park Jong-Il , Choi Seung Dueg , Park Eon Byeong , Lee Young Joo , Choi Chul , Oh Je Myung
Published: October 2009

Copper nanoparticles have been synthesized in a transferred arc plasma by controlling the various processing parameters. The structure, size distribution, phase composition of the nanoparticles were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) analysis. Copper nanoparticles dispersed in lubricant oils by bead mill process showed a good stability over a week. Lubricants containing copper nanoparticles revealed an enhanced friction properties and thermal conductivity
Some Miniaturized Impedance Sensors, Their Application to Flow Measurements and Hyphenation with High-Performance Separations
Authors: Opekar Frantisek , Tuma Petr , Stulik Karel
Published: October 2009

The present state of the theory of high-frequency impedance sensors (now mostly called contactless conductivity sensors), the principal approaches to designing impedance flow-through cells and their operational parameters are critically discussed. The most important problems to be solved in coupling these devices with high-performance separations in liquid phases are further elaborated. Examples are given of cell designs for continuous flow and flow-injection analyses, and of detection systems for miniaturized liquid chromatography and capillary electrophoresis. Typical practical analyses, mostly from the area of biology and medicine, illustrate this discussion, indicate the application range of these measurements and suggest some directions for future development.
Application of Commercial Automotive Sensor Manufacturing Methods for NOx/NH3 Mixed Potential Sensors for Vehicle On-board Emissions Control
Authors: Sekhar Praveen K. , Brosha Eric L. , Mukundan R. , Nelson Mark A. , Garzon Fernando
Published: October 2009

The article describes the application of commercial manufacturing methods to the development of NOx/NH3 sensors for vehicle on-board emissions control. Implementation of devices that respond to NOx/NH3 in real-time with improved sensitivity, selectivity and response time over conventional mixed potential gas sensors is discussed. Leveraging LANL's (Los Alamos National Laboratory) unique mixed potential sensor design, a cost-effective and mass manufacturable prototype gas sensing platform has been developed. Experimental results from these engineered devices indicate the possibility of a combined NOx/NH3 sensor platform. Moreover, the challenges and limitations towards the commercialization of mixed potential NOx/NH3 sensors are summarized.
Mackereth Oxygen Sensor: Measurement Uncertainty
Authors: Nei Lembit , Lillenberg Merike
Published: October 2009

The measurement of oxygen concentrations in natural and waste water is a major requirement of environmental monitoring. Since 1953 amperometric membrane-covered sensors are commonly used for dissolved oxygen measurements. The device consists of a two-electrode electrochemical cell with a thin gas-permeable membrane separating the electrodes and the electrolyte solution from the analyzed media. The reliability of dissolved oxygen analysis has been extensively discussed in the relevant literature. There is a remarkable disagreement between the values of measurement uncertainty of dissolved oxygen measurement reported by different authors. We draw out the main uncertainty sources and show the potential measures for increasing the reliability of continuous electrochemical oxygen measurements, carried out in environmental monitoring and waste water treatment.
Macro-homogenous Modeling of Commercial, Primary Li/MnO2 Coin Cells
Authors: Yeduvaka Gowri , Spotnitz Robert , Gering Kevin
Published: October 2009

Models of coin-type lithium manganese dioxide batteries of various sizes made by different manufacturers including Sony, Panasonic, Gold Peak and Varta were developed. These models greatly assist battery users to select the suitability of a particular cell for a specific application by enabling an evaluation to be carried out by simulation rather than actual testing. This paper presents comparison of battery data simulation results obtained by fitting parameters to macro-homogeneous model over a wide range of temperatures (-20° to +70° and loads (5.6 kΩ to 30 kΩ).
Parameter Estimation and Capacity Fade Analysis of Lithium-Ion Batteries Using First-Principles-Based Efficient Reformulated Models
Authors: Ramadesigan Venkatasailanathan , Boovaragavan Vijayasekaran , Arabandi Mounika , Chen Kejia , Tsukamoto Hisashi , Braatz Richard , Subramanian Venkat
Published: October 2009

Transport and kinetic parameters of lithium-ion batteries are estimated using a first-principles electrochemical engineering model based on porous electrode theory (1, 2). A full-order model reformulated using advanced mathematical techniques (3, 4) was used for the simulations. Since batteries and other power sources are used in hybrid environments, with devices with time constants less than a second (like a super capacitor or an induction motor), parameter estimation algorithms were developed with high computational efficiency. As a complement to approaches to mathematically model capacity fade that require detailed understanding of each mechanism (5), capacity fade was accurately and efficiently predicted for future cycles by extrapolating the change in effective transport and kinetic parameters with cycle number (N), for a battery under controlled experimental conditions. Parameter estimation using mathematical reformulation (4) was more efficient and robust than full-order models based on the traditional finite difference approach.
Integration of Vertical Carbon Nanotube Bundles for Interconnects
Authors: Chiodarelli Nicolo , Kellens Kristof , Cott Daire J. , Peys Nick , Arstila Kai , Heyns Marc M. , De Gendt Stefan , Groeseneken Guido , Vereecken Philippe M.
Published: October 2009

Carbon nanotubes (CNT) are considered a promising material for interconnects for future generation microchips. The integration of vertical CNT in a processing environment is evaluated in this work. Hypothetical CNT-based interconnects are compared with existing technologies at different hierarchy levels including the limitations of present deposition methods for copper and tungsten. For practical benchmarking, CNT bundles were selectively grown into contact holes using PVD and ECD cobalt or nickel catalysts. A polishing step was used to control the CNT length after embedding the CNT into an oxide matrix. A CNT metal decoration method based on electrodeposition is presented which can be used to assess the yield of electrically conductive CNT as well as to form top-contacts for electrical characterization. Finally, the importance of having suitable and robust structures for evaluating the integration process is highlighted after the electrical characterization of CNT in a nanoprober station.
Electrochemical Properties of Cu Deposition from Methanesulphonate Electrolytes for ULSI and MEMS Applications
Authors: Hasan Maksudul , Casey Declan , Rohan James
Published: October 2009

Methanesulphonic acid (MSA) is an alternative to sulphuric acid electrolytes. The electrochemical nucleation and growth of Cu on a glassy carbon (GC) electrode was studied from the methanesulphonate and sulphate baths. The overpotential for Cu deposition was much smaller in the MSA bath compared to the traditional sulphuric acid bath. Cu nucleation occurred at a higher rate in the MSA bath. The measured diffusion coefficient value for Cu deposition from the MSA bath was 6.82 x 10-6 cm2/s. The UV-Vis spectroscopic results confirmed that the coordination of Cu species was the same in both electrolytes. Cu electrodeposition on Ni sputtered Si substrate from the high efficiency MSA bath was found to be photoresist compatible with no void formation. 1D Cu nanorods were also deposited through AAO template on a Ni evaporated seed layer substrate showing potential applications as interconnects in ULSI and MEMS.
Pulsed Aqueous Electrodeposition of Sm-Co Permanent Magnets
Authors: Wei J. C. , Schwartz M. , Nobe K.
Published: October 2009

Pulse current electrodeposition of Sm-Co alloys from aqueous solutions has been studied at various current densities (PCD), solution temperatures, frequency (ν), Ton and duty cycles (γ). A deposit content of 20 at %Sm was obtained at 25oC, higher than at 60oC in contrast to DC from bath of 1M Sm sulfamate, 0.05M Co sulfate, 0.15M glycine at pH6. This composition is sufficient to obtain the high performance permanent magnet intermetallics, Sm2Co17 (10.5 at %) and SmCo5 (16.7 at %), by appropriate heat treatment. Increased PCD, Ton, g and decreased solution temperature or frequency increased Sm deposit content and decreased current efficiency (CE). Magnetic saturation(Ms) decreased linearly with increased Sm deposit content as DC and sputtered films. Increased Sm content resulted in significant decrease in Hc⊥ but Hc|| varied little.
Nanoscale Topography Measurements with a Metal Nanowire AFM Tip
Authors: Motoyama Munekazu , Prinz Friedrich B.
Published: October 2009

This paper describes comparison between atomic force microscope (AFM) measurements with a Si tip and a 200-nm-diameter Ni nanowire tip. A produced nanowire AFM probe successfully produced topographic images showing profiles convoluted with a tip radius of 100-200 nm. Bending stiffness of metal nanowires realizes a smaller lateral spring constant than Si and Si3N4 tips. Inelastic deformations of nanowires occurred under excessive loads. The maximum end deflections for nanowires to break the elasticity, which beam mechanics indicates, were applicable to our observed results.
Engineering Performance in TCO Films for Energy Applications
Authors: Exarhos Greg
Published: October 2009

Thin film materials that exhibit both good electrical conductivity and high transparency owe this duality to careful control of the chemical state of the constituents and the attendant structure. Through manipulation of deposition conditions n- or p-type semi-conducting oxide films readily can be prepared. Such films enable the performance of energy conversion devices and promote development of architectural elements including smart energy efficient windows. This paper summarizes current TCO research trends, reviews processing approaches, and offers guidelines for engineering high performance TCO films. Also provided is a glimpse of optical engineering approaches where impedance matching and quantum mechanical tunneling offer alternative avenues to further improvement of film properties.
Formation and Characterization of P(VDF-TeFE) Films Using Sol-Gel Methods for Application to Micro-Generators
Authors: Jeong Jong-Hyeon , Kimura Chiharu , Aoki Hidemitsu , Okuyama Masanori , Sugino Takashi
Published: October 2009

In order to apply the P(VDF-TeFE) piezoelectric polymer to the micro-generator based on MEMS technology, we have established a process condition of the film formation. A solvent which is used to cast P(VDF-TeFE) solution is important factor for film formation, and MEK solvent has some problems such as low adhesion for low concentration and drying on a coating process for high concentration. Some problems are suppressed by adding a DMA solvent. However, a DMA solvent affected a molecular structure of the film. A thermal treatment is also an important factor since film stretching cannot be allowed in a spin-coating process. In order to compare the single-solvent solution with the mixed-solvent solution, we have carried out qualitative analysis of the film in formation processes.
On the Development of a General Electrochemical Impedance Model
Authors: Tokash Justin , Engelhardt George , Macdonald Digby D.
Published: October 2009

A general model and computer code have been developed for writing down by inspection the impedance of one-dimensional systems involving arbitrary numbers of coupled electrochemical and chemical processes under activation or mass transport control. This code is based on the direct solution of the mass transport equations by using the finite difference up-wind scheme. The current version of the code is able to handle any arbitrary number (and complexity) of homogeneous and heterogeneous reactions. This code simulates, and can be used for optimization on, coupled chemical/electrochemical reaction mechanisms at rotating disk electrode or by using the Nernst diffusion layer approximation. The model can be readily optimized on experimental EIS data, in order to determine values for various model parameters (rate constants, transfer coefficients, diffusivities, etc). The application of the code is illustrated with "synthetic" EIS data and with some experimental data obtained on a rotating disk electrode.
DC Compliance Bias Introduced by a Potentiostat: Effects During AC Impedance Measurements and Possible Prevention
Authors: Vanysek Petr , Tavassol Hadi
Published: October 2009

The 4-point conductivity measurements are preferred in conductivity measurements as they are less affected by polarization as a result of surface electrochemical reactions. An immersion 4-electrode conductivity probe marketed by Topac was used for impedance measurements and finally, for conductivity studies. The conductivity measurements of standard solutions of potassium chloride, yielded a value for the cell constant close to the one expected one from geometry. After multiple repetitions of impedance measurements a change in appearance of the working electrodes (from platinized black to shiny metallic) was observed. This lead to the discovery that in a 4-electrode system without explicit reference electrodes the potentiostat enters into slow frequency oscillations and the resulting compliance voltage causes electropolishing of the electrodes. Although the impedance measurements, at least in this case, were not burdened by this apparent excessive current on the counterelectrodes, a method to avoid this problem by working in galvanostatic, instead of potentiostatic mode is proposed.