bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunization of Mice with Live-Attenuated Late Liver Stage-Arresting Plasmodium yoelii Parasites Generates Protective Antibody Responses to Preerythrocytic Stages of Malaria
Authors: Keitany Gladys J. , Sack Brandon , Smithers Hannah , Chen Lin , Jang Ihn K. , Sebastian Leslie , Gupta Megha , Sather D. Noah , Vignali Marissa , Vaughan Ashley M. , Kappe Stefan H. I. , Wang Ruobing
Published: September 2014

Understanding protective immunity to malaria is essential for the design of an effective vaccine to prevent the large number of infections and deaths caused by this parasitic disease. To date, whole-parasite immunization with attenuated parasites is the most effective method to confer sterile protection against malaria infection in clinical trials. Mouse model studies have highlighted the essential role that CD8+T cells play in protection against preerythrocytic stages of malaria; however, there is mounting evidence that antibodies are also important in these stages. Here, we show that experimental immunization of mice withPlasmodium yoeliifabb/f−(Pyfabb/f−), a genetically attenuated rodent malaria parasite that arrests late in the liver stage, induced functional antibodies that inhibited hepatocyte invasionin vitroand reduced liver-stage burdenin vivo. These antibodies were sufficient to induce sterile protection from challenge byP. yoeliisporozoites in the absence of T cells in 50% of mice when sporozoites were administered by mosquito bite but not when they were administered by intravenous injection. Moreover, among mice challenged by mosquito bite, a higher proportion of BALB/c mice than C57BL/6 mice developed sterile protection (62.5% and 37.5%, respectively). Analysis of the antibody isotypes induced by immunization withPyfabb/f−showed that, overall, BALB/c mice developed an IgG1-biased response, whereas C57BL/6 mice developed an IgG2b/c-biased response. Our data demonstrate for the first time that antibodies induced by experimental immunization of mice with a genetically attenuated rodent parasite play a protective role during the preerythrocytic stages of malaria. Furthermore, they highlight the importance of considering both the route of challenge and the genetic background of the mouse strains used when interpreting vaccine efficacy studies in animal models of malaria infection.
Buprenorphine provides better anaesthetic conditions than butorphanol for field castration in ponies: results of a randomised clinical trial
Authors: Rigotti C. , Vries A. De , Taylor P. M.
Published: September 2014

A prospective, randomised, blinded, clinical trial in 47 ponies compared butorphanol and buprenorphine administered intravenously with detomidine prior to castration under anaesthesia. Detomidine 12 μg/kg intravenously was followed by butorphanol 25 μg/kg (BUT) or buprenorphine 5 μg/kg (BUP) before induction of anaesthesia with intravenous ketamine and diazepam. Quality of sedation, induction and recovery from anaesthesia, response to tactile stimulation, and surgical conditions were scored. If anaesthesia was inadequate ‘rescue’ was given with intravenous ketamine (maximum three doses) followed by intravenous thiopental and detomidine. Time from induction to first rescue, total ketamine dose and number of rescues were recorded. Postoperative locomotor activity was scored and abnormal behaviour noted. Simple descriptive scales were used for all scoring. Data were analysed using two‐way analysis of variance, t tests, Mann‐Whitney or Fisher's exact tests as appropriate; P<0.05 was considered statistically significant. Cryptorchid animals did not undergo surgery, but castration was successfully completed in 18 BUT and 20 BUP. More incremental ketamine (P=0.0310) and more rescue drugs (P=0.0165) were required in BUT and more postoperative locomotor activity occurred in BUP (P=0.0001). There were no other differences between groups. Both opioids were suitable for premedication prior to castration but buprenorphine appeared to provide better intraoperative analgesia.
The association between arterial properties and blood pressure in children
Authors: Phillips Aaron A. , Chirico Daniele , Coverdale Nicole S. , Fitzgibbon Laura K. , Shoemaker J. Kevin , Wade Terrance J. , Cairney John , O’Leary Deborah D.
Published: September 2014

Elevated blood pressure (BP) in adults is associated with increased arterial stiffness and thickness; however, its effect on arterial health in a pediatric population is less understood. The purpose of this study was to identify the relationship between childhood BP and arterial markers of arteriosclerotic progression. The study consisted of 106 children across a wide range of BP values divided into 2 BP groups: high BP (HBP; ≥95th percentile; n = 21) and normal BP (NBP; <90th percentile; n = 85) based on consistent automated BP measures taken at 2 time points. The laboratory examination involved systemic pulse wave velocity (PWV), common carotid artery (CCA) intima media thickness (IMT) and distensibility, as well as body mass index (BMI) and pubertal maturation. BMI and heart rate, as well as PWV (HBP: n = 15 and NBP: n = 56), were higher in the HBP group (p < 0.001) with no difference between groups for both CCA distensibility and IMT (HBP: n = 21 and NBP: n = 83). Multivariate linear regression revealed that BP group (p = 0.003) was an independent predictor of PWV after controlling for age, sex, BMI, heart rate, and maturation. Our findings demonstrate a higher systemic PWV with no difference in CCA IMT or distensibility in children with elevated BP. Hence, markers of cardiovascular disease risk are augmented in healthy children with elevated BP.
First-principles quantum transport in S3 clusters
Authors: Yu Jing-Xin , Liu Xiu-Ying , Zhang Li-Ying , Cheng Yan , Chen Xiang-Rong
Published: September 2014

The quantum transport in S3 clusters sandwiched between Au electrodes was investigated using density functional theory and nonequilibrium Green's function method. Five different configurations were considered, and the equilibrium conductance and the projected density of states were obtained at optimal positions. Results revealed local minima for two strain chains connected to the pyramidal electrodes at the top site and a triangular S3 open chain linked to the pyramidal electrodes at the top hollow site. The relationship between conductance and external bias voltage was also calculated. Transmission of straight chains was determined by resonance and strongly affected by the bias voltage. Transport of top-hollow configuration was dominated by several closely spaced and broad molecular orbitals; hence, the transmission coefficient was almost flat around the gold Fermi level. The calculations proved that the coupling morphologies of S3 clusters connected with the electrodes significantly affected the electrical transport properties of nanoscale junctions.
NEW APPROACH TO CHARACTERIZE THE CONFIGURATION OF FRACTURED ROCK SURFACE INDIRECTLY
Authors: LI YE XUE , LI ZHENG , FAN JIAN HUI , JIA ZHI YONG
Published: September 2014

A novel approach called the YUV dimension method is proposed in this study to indirectly characterize fractured rock surface topography. This model is based on YUV color model theory in iconography and graphics. The process is described in detail as follows. A true-color photo with m pixels is selected. Y is denoted by gray scale, U by hue, and V by the saturation components of the pixel color. These components are applied to create the z, x and y coordinates of the point in the coordinate system that originates from the pixel. A similar method is applied in each pixel. M points are created in the coordinate space. The number of created points is equivalent to one of the pixels. The m points are then connected and a rough YUV surface is established. Otherwise, the calculation method for the self-affine dimension of a n - 1 ~ n-dimensional fractal body is presented by fractal Brownian motion theory and then degenerated to one between the 2D and 3D case. The approach is applied to evaluate the dimension of the YUV surface, i.e. the YUV dimension. To validate the feasibility of YUV dimension theory, numerical studies on the YUV dimension are conducted through a laser profilometer scanning experiment and scanning electron microscopy with the same specimens. The surface characteristics of similar samples are analyzed by probing into the YUV, general and grayscale dimensions of the specimens. The comparison shows that the YUV and general dimensions of similar specimens are fundamentally identical, and the complete trends of the YUV and gray dimensions remain consistent with changing specimens. The result indicates that YUV dimension theory is reasonable and feasible. In short, the YUV dimension is a new method that exhibits more advantages than the general and grayscale dimensions. This method characterizes surface configuration indirectly.
THE BIOMECHANICAL EFFECTS OF CEMENT AUGMENTATION AND PARTIAL VERTEBRAL HEIGHT RESTORATION ON THE LOAD TRANSFER CHANGE OF ADJACENT VERTEBRAE IN VERTEBROPLASTY
Authors: LIN CHIEN-YU , CHEN WENG-PIN , LAI PO-LIANG , CHUANG SHIH-YOUENG , JU DA-TONG , CHIANG CHANG-JUNG
Published: September 2014

Vertebroplasty is commonly used to treat vertebral wedge fractures (VWFs). However, differing degrees of vertebral height restoration (VHR) have been reported after vertebroplasty, and little is known about how grades (steepness) of VWF deformities affect loadings on the fractured and adjacent unfractured vertebrae. Therefore, the goal of this study was to create a non-linear finite element (FE) model of the T10–L2 thoracolumbar segments. With this model, we aimed to evaluate the biomechanical outcomes of three different collapse models (25%, 50%, and 75%) at the T12 vertebra before and after cement augmentation (CA) and with and without VHR. In these VWF simulations, the forces of the erector spinae, the intradiscal pressure, and the maximum von Mises stresses in the endplates and vertebral bodies increased as vertebral deformation increased. Performing CA alone, without restoring vertebral height for the fractured vertebra, did not change the stiffness of multiple spinal segments or the pressures on the adjacent disc, but it did decrease stresses on the endplates and the vertebral bone. A 10% restoration of vertebral height after CA reduced the maximum von Mises stress in the endplates and bone structures more than when CA did not restore vertebral height (no VHR). These results suggest that achieving partial VHR during vertebroplasty may help prevent postvertebroplasty fractures in the fractured and adjacent vertebrae.
Miniaturization of Photothermal Cantilever Deflection Spectroscopy with an Electrical Readout
Authors: Kim Seonghwan , Lee Dongkyu , Thundat Thomas
Published: September 2014

The chemical selectivity challenge of microcantilever sensors can be overcome by photothermal cantilever deflection spectroscopy (PCDS). A bi-material cantilever responds to heat generated by non-radiative decay process when the adsorbed molecules are resonantly excited with infrared (IR) light. The variation in cantilever deflection amplitude as a function of illuminating IR wavelength corresponds to the conventional IR absorption spectrum of the adsorbed molecules. In addition, the mass of the adsorbed molecules can be determined by measuring the resonance frequency shift of the cantilever for the quantitative analysis. This technique offers unprecedented opportunities for highly selective as well as sensitive chemical sensing without relying on chemoselective interfaces. However, conventional optical signal readout schemes employed for microcantilever sensors pose challenges on miniaturization and system level integration. Here, we demonstrate PCDS using a piezoresistive cantilever which can be easily miniaturized and integrated into a portable sensor platform.
Sensor for Quantitative Analytical Determination of Sulphite in Wine Using a System of Modified Electrode and a Membrane Absorption System
Authors: Arce Roxana , Aguirre María Jesús , Romero Julio
Published: September 2014

In this work we present the comparison among three glassy carbon electrodes modified by Co-porphyrin (CoTAPP), ortho-phenylendiamine (OPD), or both, simultaneously. This comparison shows the differences among their electrochemical behavior and their electrocatalytic behavior toward the oxidation of sulfite. In the case of the glassy carbon modified electrodes, the presence of the copolymer enhances the electrocatalytic performance of the modified electrodes in spite of the non-catalytic response (compared to the bare glassy carbon) of both homopolymers-modified electrodes toward the oxidation of sulfite. Also, the oxidation of sulfite extracted from red wine is showed. The copolymer-modified electrode is capable of oxidizing the extracted free sulfite in a 0.02 M NaOH solution. Through the addition of standards method, a concentration of 44 ppm for free sulfite is found in a Chilean red wine.
Phospholipid Sensors for Detection of Bacterial Pore-Forming Toxins
Authors: Valincius Gintaras , Budvytyte Rima , Penkauskas Tadas , Pleckaityte Milda , Zvirbliene Aurelija
Published: September 2014

We describe phospholipid bilayer sensors for detection of activity of cholesterol dependent cytolysins (CDCs) comprising a class of structurally related proteins. We focus on vaginolysin (VLY) secreted by the bacteria Gardnerella vaginalis, which is a virulent factor in bacterial vaginosis. CDCs are strictly dependent on cholesterol. To measure the activity of VLY we developed tethered bilayers with controlled amount of cholesterol. Such bilayers are sensitive to VLY in a concentration dependent manner. Sensitivity of bilayers can be modulated by the cholesterol content. Membrane damage by VLY is easily detected at the subnanomolar concentration range utilizing the electrochemical impedance spectroscopy (EIS). An EIS data analysis algorithm allowing estimating density of protein pores is presented. Other pore-forming cholesterol dependent toxins such as intermedilysin affects phospholipid bilayer in a similar way as VLY. However, to achieve maximal performance of a phospholipid sensor the composition of tethered bilayers needs to be adjusted individually.
Nano and Bio Sensors for Life Sciences Applications
Authors: Aguilar Zoraida Pascual , Al-Ogaidi Israa , Suri Savan , Gou Honglei , Wu Nianqiang , Xu Hengyi , Wei Hua , Wang Andrew
Published: September 2014

Sensors applications represent one of the most promising commercial products developments. The Global Industry Analysts predicted that in 2017, the global market for biosensors in medical diagnostics would reach US$16.5 billion. The increased R&D focused on highly accurate real-time diagnosis using biosensors and the demand for biosensors based equipment drives this market. The emergence of new technologies including nanomaterials based-sensors, microfluidics, and non-invasive sensors also act as other market drivers. Until 2016, diagnostic sensors for point of care will continue to drive the market while biodefense and environmental markets are predicted to have the highest CAGRs at 13%–15%. This paper will focus on the preliminary studies in the development of nano and bio sensors for life sciences applications. Data gathered for detection of disease biomarkers using nanotechnology, electrochemistry, and colorimetric methods will be discussed. Studies on the development of lateral flow strip tests, glass slide-based sensors, and 96-well plate assays using quantum dots fluorescence, absorbance, and electrochemical detection methods will be presented.
Porous Silicon MEMS Infrared Filters for Micromechanical Photothermal Spectroscopy
Authors: Kozak Dmitry A , Stievater Todd H , Pruessner Marcel W , Nierenberg Kerry , Rabinovich William S
Published: September 2014

We report on the progress towards an integrated system for optical spectroscopy of gases. The system is composed of two MEMS devices, a tunable optical filter and a photothermal spectrometer. Progress in the development of each component is discussed, with emphasis on the utilization of porous silicon to manufacture the components of the tunable filter.
Unique Applications of Megasonic Energy to MEMS Single Substrate Wet Processes
Authors: Dussault Donald , Dragoi Viorel
Published: September 2014

The work presented in this paper describes experimental results achieved through the use of megasonic energy in standard MEMS wet processes in two different areas, microlithography (photo resist strip) and wafer cleaning. In all experiments the substrates were processed in a single wafer spin module with a large area megasonic transducer held in proximity to the substrate surface.
Thermally Robust Thin-Film SOFCs for Mobile Application
Authors: Kim Kun Joong , Park Byung Hyun , Choi Gyeong Man
Published: September 2014

Micro-solid oxide fuel cells (SOFCs) is newly designed and fabricated using porous stainless-steel (STS) as a support. The thin-film components with nano-porous electrodes and dense electrolyte, i.e., La0.7Sr0.3CoO3-
δ (LSC, ~1μm) | 8YSZ (~1μm) | Ni-8YSZ (~1μm), are deposited by using pulsed laser deposition (PLD) method and show the high power density (~560 mW/cm2 at 550oC). In addition, thermal cycling characteristic, tested for the first time, show that the cells cycled between 100 and 550oC with 100oC/min rate exhibit little performance drop. These results strongly demonstrate the cell for portable mobile application.
Reaction Characteristics around Triple Phase Boundary in Anode Including Proton Conductor for Solid Oxide Fuel Cell
Authors: Nagasawa Tsuyoshi , Hanamura Katsunori
Published: September 2014

A modified reaction model around a triple phase boundary (TPB) was proposed for solid oxide fuel cells (SOFCs) with an anode containing proton conductor particles to describe the mechanism of anode overpotential reduction. In this model, three kinds of TPBs consisting of nickel metal, oxide ion conductor, proton conductor, and gas phases were considered. It was assumed that the chemical species could be adsorbed within a finite narrow area on each material around the TPB, and the reaction rate in the anode was controlled by the surface reaction between Had and Oad, while all other reactions took place under chemical equilibrium. Based on the reaction model, simple expressions for the anode overpotential could be obtained as functions of the current density related to the oxygen activity. The analytical results agreed with the experimental results in both cases, the conventional anode and new anode incorporating a proton conductor.
Synthesis and Characterization of Double-Doped Bismuth Oxide Electrolytes for Lower Temperature SOFC Application
Authors: Ruth Ashley Lidie , Lee Kang Taek , Clites Mallory , Wachsman Eric D.
Published: September 2014

High ionic conductivity double-doped bismuth oxide materials were synthesized using solid state and wet chemical methods to achieve lower total doping while maintaining phase stability. The ionic conductivity for DGSB, DWSB, and DCSB at 650°C are measured to be 0.94 S/cm, 0.53 S/cm, and 0.45 S/cm respectively. The nanopowder forms were incorporated into a bilayer electrolyte and successfully sintered dense onto a prefabricated anode and single electrolyte substrate. DGSB achieved the highest power density of 1.31 W/cm2, twice that of the single-doped erbium stabilized bismuth oxide case with the same configuration (0.60 W/cm2) as a result in the improvement in conductivity over the single-doped case.
Poisoning Effect of Sulfur Compounds in Pulse Jet-Rechargeable Direct Carbon Fuel Cells
Authors: Hattori Sayuri , Sugiyama Shiori , Tanaka Hiroki , Chen Ying , Ihara Manabu
Published: September 2014

Pulse Jet-Rechargeable Direct Carbon Fuel Cells (PJ-RDCFCs) in which liquid hydrocarbon is supplied at regular intervals is one application of SOFCs. Most commercial liquid hydrocarbon fuel contains sulfur-based impurities, and thus their poisoning effect on power generation must be considered. In this study, power generation characteristics of PJ-RDCFCs were investigated using supplied fuel containing sulfur over a wide range of fuel-supply interval times (T
int: time between fuel pulses). Under both flow-like conditions where T
int was short (≤ 5 sec) and pulse-supply condition where T
int was long (≥ 10 sec), the power density (P) decreased when fuel with sulfur was supplied. The P of a PJ-RDCFC and the degradation rate evaluated by using hydrogen before and after the power generation had the dependence on T
int.
(Plenary) FCEV Development at Nissan
Authors: Iiyama Akihiro , Tabuchi Yuichiro , Ohma A. , Sugawara Seiho , Shinohara Kazuhiko
Published: September 2014

Further cost reduction would still remain as the big challenge for FCEV full penetration. Key factors for this issue are the reduction of Pt loading and high current density operation by mass transfer improvement. This paper introduces research activities in Nissan aiming the FCEV full penetration.
(Invited) Enhanced Activities for the Oxygen Reduction Reaction at Pt-Skin Layers on Pt-Co Alloy Single-Crystal Electrodes
Authors: Wakisaka Mitsuru , Morishima Shoya , Tryk Donald A. , Uchida Hiroyuki , Watanabe Masahiro
Published: September 2014

The kinetically-controlled current densities, j
k for the oxygen reduction reaction (ORR) were evaluated at Pt skin layers formed on Pt100−x
Co
x
(111) single-crystal electrodes in air-saturated 0.1 M HClO4 solution as a function of Co content, x atom%, by use of the rotating disk electrode method. We found a maximum j
k value as high as 3.0 mA cm−2 at 0.9 V vs. RHE on the Pt skin/Pt75Co25(111) electrode, which is more than 20 times higher than that on the Pt(111) electrode. The enhanced ORR activities of Pt-skin/Pt-Co(111) electrodes cannot be explained on the basis of decreased “OH poisoning,” because the surface oxidation charge densities up to 0.9 V in N2-purged solution were nearly constant, irrespective of Co content.
Pt Catalysts Supported on Polybenzimidazole-Grafted Graphene for PEMFCs
Authors: Li Zhe-Fei , Zhang Hangyu , Yang Fan , Stanciu Lia , Xie Jian
Published: September 2014

Polybenzimidazole (PBI)-grafted Graphene supported Pt catalyst have been prepared for PEMFC application. NMR and XPS revealed that PBI have been grafted onto graphene. The Pt nanoparticles decorated on PBI-grafted graphene exhibited uniform distribution with average particle size about 2.3 nm. The PBI-grafted graphene supported Pt catalyst showed a comparable ECSA and ORR activity with commercial Pt/C catalyst, but a much better electrochemical stability. The increase in the stability of catalyst may result from the strong binding of Pt nanoparticles onto PBI-grafted graphene. Consequently, the corrosion of carbon support and leaching of Pt nanoparticles can be significantly suppressed.
Pt/SnO2 Electrocatalysts on Conductive Fillers
Authors: Horiguchi Dai , Tsukatsune Takuya , Noda Zhiyun , Hayashi Akari , Sasaki Kazunari
Published: September 2014

For polymer electrolyte fuel cells (PEFCs), corrosion of the carbon support of lectrocatalysts under cathode conditions is one of the important technical issues to solve, for which SnO2 is a promising alternative support material. In this study, Pt/SnO2 electrocatalysts with integrated conductive fillers have been developed, where the fillers act as the backbone and the built-in electron-conductive pathway. Electrochemical activity and durability of such electrocatalysts against voltage cycling between 1.0 and 1.5 VRHE are investigated. This durable electrocatalyst exhibits higher the oxygen reduction reaction (ORR) activity than Pt/SnO2, and comparable ORR activity to that of the standard Pt/C electrocatalysts.
Alternative Oxide-Supported PEFC Electrocatalysts
Authors: Sasaki Kazunari , Noda Zhiyun , Tsukatsune Takuya , Kanda Kohei , Takabatake Yuma , Nagamatsu Yohei , Daio Takeshi , Lyth Stephen Matthew , Hayashi Akari
Published: September 2014

Possible alternative electrocatalyst support materials to the conventional carbon black have been examined. Among others, doped-SnO2 can be a promising support for Pt nanoparticles well connected to the oxide with a certain crystallographic orientation. Pt/doped SnO2 exhibits suitable voltage cycle durability, while further improvement in oxygen reduction reaction (ORR) activity is still desired.
Analysis of Cathode Catalyst Layer Structure and Cell Performance in PEFC
Authors: Akabori Sho , Suzuki Kengo , Tabe Yutaka , Chikahisa Takemi
Published: September 2014

For efficient use of Pt catalyst in polymer electrolyte membrane fuel cells (PEFCs), the effect of the cathode catalyst layer (CL) structure on the I-V characteristics was evaluated by a model analysis, and superior fabrication method was investigated experimentally. The experimental results showed that reducing the hot-pressing pressure and increasing the mixing intensity of the catalyst ink in the fabrication process of the catalyst coated membrane (CCM) improve the cell performance, and the measured pore size distribution (PSD) in the CL indicated the effect of the increase in agglomerate surface area on the performance improvement. In addition, we developed a method for estimating the mean diameter and the dispersion of the agglomerates from the PSD. The effect of the estimated CL structure on the cell performance was also examined by the model analysis for the CCMs fabricated by the different conditions.
Effect of Electrode Patterning on PEM Fuel Cell Performance using Ink-Jet Printing Method
Authors: Shukla Shantanu , Domican Kailyn , Secanell Marc
Published: September 2014

The suitability of inkjet printing technology for patterning fuel cell electrodes was investigated. A study on resolution of the inkjet printer showed that micro-scale distinguishable patterns can be fabricated within a spacing of 300 microns. The performance of the patterned and non-patterned electrodes were compared from the polarization plot obtained at a cell temperature of 80◦C and 70% RH with an estimated cathodic loading of 0.075 mg/cm2. Preliminary results show that under the current operating conditions, not much change in performance is observed, however the patterned electrodes have the potential to achieve higher limiting currents when the masstransport effects are dominant and is being currently investigated.
Ceria and Doped Ceria Nanoparticle Additives for Polymer Fuel Cell Lifetime Improvement
Authors: Stewart S. Michael , Borup Rod L , Wilson Mahlon S. , Datye Abhaya , Garzon Fernando H.
Published: September 2014

Polymer electrolyte fuel cell membranes are degraded by oxygen free radical attack. The addition of cerium oxide and doped cerium oxide nanoparticles improves membrane stability as measured by open circuit voltage and low humidity accelerated stress testing. In this work we varied the crystallite size of ceria nanoparticles and investigated their role in enhancing durability of the PEM fuel cell. We found that the ratio of the free radical production to hydrogen peroxide decomposition rates provides a novel approach to characterize the efficiency of free radical scavenging catalysts. Nanoparticle crystallite size and doping plays a significant role in determining the surface area normalized efficiency of ceria based free radical scavengers.
Quantum Chemical Analysis about Deprotonation Reaction of Sulfonic Group of Modeled Hydrocarbon Membrane in Low Hydration Level
Authors: Sakai Hironori , Tokumasu Takashi
Published: September 2014

Ease of deprotonation what is called acidity about sulfonic group of model molecules of perfluorosulfonic acid (PFSA) membrane and hydrocarbon (HC) membrane was focused on in this study. The deprotonation reaction of sulfonic group by water molecules were analyzed by density functional theory in low hydration levels. Target hydration levels were one to three. Calculation level was B3LYP/6-311+G(d,p). As a result, sulfonic group of model molecules of PFSA is deprotonated in hydration level three via low activation energy. In addition, deprotonated state (SO3
- group, H3O+ and two water molecules) is more stable than the protonated state (sulfonic group and three water molecules). On the other hand, deprotonated state of model molecule of HC in hydration level three is unstable. In addition, activation energy is relatively high. Those properties indicate sulfonic group of HC membrane is relatively hard to deprotonate in comparison with PFSA membrane in the same hydration level.
Polymer Electrolyte Membrane Fuel Cells: Characterization and Diagnostics
Authors: Dhanushkodi Shankar , Schwager Maximilian , Mérida Walter
Published: September 2014

The normal operation of polymer electrolyte membrane fuel cells (PEMFCs) can induce significant temperature, humidity, pressure or concentration gradients across the cell’s active area. The overall performance and stability can be affected negatively by these gradients, and they may contribute to material degradation, and ultimately, to cell failure. We report on diagnostic techniques and methodologies to characterize PEMFC material properties and the inhomogeneities across the active area of a working cell. Specifically, we describe in-situ techniques for the spatially-resolved characterization of PEMFC performance. Our testing hardware features sixteen fully isolated segments over a 49 cm2 active area, reference electrode capabilities, and individual segment control. The techniques are applied to the in-situ characterization of effective platinum surface area (EPSA) degradation under 1×105 accelerated stress testing (AST) cycles.
Molecular Simulation of Oxygen Permeation through Ionomer in Catalyst Layer
Authors: Kurihara Yuya , Mabuchi Takuya , Tokumasu Takashi
Published: September 2014

We analyzed oxygen permeability through the two different types of thin ionomer films, composed of Nafion and hydrocarbon (HC), on Pt surface. From the results of the number of permeated oxygen, density distributions of ionomer components and oxygen, and solubility distributions of oxygen, we have found that the number of permeated oxygen molecules decreases in both ionomers as water content increases. In the ionomer-gas interface and the bulk region of both ionomers, the oxygen solubility decreases, and solvent block the diffusion of oxygen with increasing water content. In the ionomer-Pt interface of the Nafion-based ionomer, the oxygen solubility also decreases, and the voids in the ionomer, which can be the pathways for oxygen, are occupied by solvent at higher water contents. On the other hand, in the interface of the HC-based ionomer, solvent molecules are piled up on the surface of high-density polymers, and block the permeation of oxygen.
Multi-Scale Analysis for Automotive PEM Fuel Cell System: Macro-Scale Analysis
Authors: Shimpalee Sirivatch , Lilavivat Visarn , Hirano Shinichi , Pence Benjamin , Wilkosz Deniel , DeBolt Michael , Saloka G
Published: September 2014

The objective of this work is to establish the design principles of a proton exchange membrane fuel cell (PEMFC) for automotive applications. In this part, the macro-scale analysis was considered to create the overall design principle. A combination of experiments and numerical simulations were carried out and the results analyzed to enhance understanding of the behavior of a 300-cm2 flow field PEMFC. A three-dimensional (3D) computational fluid dynamics (CFD)-based methodology was used to predict such as the current and temperature distributions of this design. The effect of flow direction and the cooling pattern on this design were also taken into account to enhance the understanding for this selected flow field design.
An Improved EVB Model for Proton Transport in Polymer Electrolyte Membrane
Authors: Mabuchi Takuya , Tokumasu Takashi
Published: September 2014

We have performed a detailed analysis of proton solvation and transport properties in hydrated Nafion using molecular dynamics simulation. The revised EVB model predicts a significantly enhanced transport in comparison with the classical hydronium models, which largely improves the agreement with the available experimental data. The excess proton was found to have weaker interaction with the sulfonate groups in comparison with the classical hydronium ion, reflecting the delocalization nature of the proton charge defects in the EVB model. Our results suggest that the hopping transport has a large contribution to the proton diffusion even at lower hydration levels, as low as 3. It was also found that the Grotthuss component becomes more important and its contribution increases linearly as the hydration level increases.
Durability Analysis and Improvement of Modified Cathode Electrocatalyst to Operate PEFC Cell under Low Relative Humidity
Authors: Nakajima Hitoshi , Matsutani Koichi
Published: September 2014

The modification of cathode catalyst was effective to improve cell performance under low relative humidity. Here we report the stability of the modified cathode Pt catalysts under low RH. The time dependences of the cell voltage of fixed current density operation at 0.5 A cm-2 (H2 / Air) under RH=31% were measured. The cell voltage drop with time was almost finished after 20 h. The cell voltage after 33 h was around 0.46 V by using modified cathode electrocatalyst (initial cell voltage was 0.53 V), on the other hand, the cell voltage dropped to 0.42 V only after 20 h by using unmodified one (initial cell voltage was 0.48 V). The time dependences of the cell voltage of fixed current density operation at 0.8 A cm-2 under RH=31% were also measured. In this case, the drop of cell voltage was continued in both catalysts throughout the operation.
The Effect of Common Airborne Impurities and Mixtures on PEMFC Performance and Durability
Authors: Angelo Michael , St-Pierre Jean
Published: September 2014

The effect of exposing the cathode of hydrogen (H2) proton exchange membrane fuel cells (PEMFCs) to the airborne contaminants: sulfur dioxide (SO2), benzene (BZ), and nitrogen dioxide (NO2) on their performance and durability was studied for individual contaminants and mixtures at a total concentration of two parts per million (ppm). The goals were to characterize the effects of contaminant exposure on the: (i) cell performance, (ii) ability of the fuel cell to recover performance using only pure air, (iii) irrecoverable performance loss, and (iv) changes to the durability of the fuel cell as quantified by changes to the electrochemically active surface area (ECSA) of the electrodes. In general, contaminant mixtures decreased performance more than single contaminants. Performance loss was recoverable with pure air when no SO2 was in the stream and incomplete when it was. Contaminant exposure accelerated ECSA loss.
Performance Variation of Flexible Polymer Electrolyte Fuel Cell with Ag Nanowire Current Collector under Torsion
Authors: Park Taehyun , Chang Ikwhang , Lee Jinhwan , Ko Seung Hwan , Cha Suk Won
Published: September 2014

Performance variation of flexible fuel cell based on polydimethylsiloxane coated with Ag nanowires percolation network for current collection was characterized as torsion on it increases. Maximum power densities of flexible fuel cell at no torsion and 0 degree of torsion were 16.8 and 10.9 mW/cm2, respectively, showing decreasing tendency of power density as torsion increases. By measuring electrochemical impedances, it was found that cause for decreased electrochemical performance was increased ohmic and faradaic resistances. In addition, inhomogeneous distribution of hydrogen and air in fuel cell caused by torsion contributed to decrease of faradaic resistance and resulting electrical performance. From solid-mechanical model of finite element analysis, generated internal stress by torsion was not severe and the decreased performance was not the effect of contact resistance, which was already reported in our previous study.
Hydrogen Production on an Ethanol Dehydrogenation Reactor Coupled to a Conventional PEMFC
Authors: Sato André Gustavo , Silva Gabriel Cristiano da , Paganin Valdecir Antonio , Ticianelli Edson A.
Published: September 2014

On board hydrogen storage has become a key factor for the technical viability of fuel cell driven electric or hybrid vehicles. In this work we present results of a system which comprises an ethanol dehydrogenation catalytic unit coupled to a conventional proton exchange membrane fuel cell (PEMFC). Ethanol is first dehydrogenated over a Cu/ZrO2 catalyst bed, and then the gas effluent is trapped in a simple cold condenser enabling a gas current rich in H2 to feed a PEMFC. Chronoamperometry (at a cell potential of 700 mV) showed apparent stability of the cell performance at about 300 mA cm-2 (with H2 produced from ethanol reaction) whilst at 550 mA cm-2 with pure H2. Maximum cell power density of our integrated system achieved almost 70% of the performance of the cell powered with pure H2.
Interfacial Phenomena of Alkalimetal Carbonate on Sm-Doped Ceria for Composite Electrolytes
Authors: Mizuhata Minoru , Takeda Kaori , Maki Hideshi
Published: September 2014

High temperature Raman spectroscopy of Sm doped CeO2/carbonate composite was measured in order to discuss the interaction between carbonate ion and solid oxide electrolyte at an interface in Sm doped CeO2/carbonate LT-SOFC. In Raman spectra with temperature of carbonate breathing mode of NK in initial heating process, whereas separated ν1(CO3
2-) bands assigned to Na2CO3 and K2CO3 are observed clearly at lower temperature, unifying of these bands was observed due to solid state migration of carbonates at temperature lower than eutectic point (983 K). Degree of migration is affected by apparent average thickness (AAT) and Sm amount in oxide. Solid state diffusion at temperature lower than eutectic point of carbonate mixture is assisted by coexistence of solid oxides.
Synthesis of Novel Ionic Liquids with Aromatic Trifluoroborate Anions
Authors: Iwasaki Kazuki , Yoshii Kazuki , Tsuzuki Seiji , Tsuda Tetsuya , Kuwabata Susumu
Published: September 2014

Aromatic trifluoroborate ([Ar-BF3]−) is a useful anion structure for molten salt and ionic liquid (IL) designing because we can attach various sorts of substituents on the aromatic ring with ease. A number of alkali metal salts having [Ar-BF3]− were synthesized and their physical properties were measured. The salts showed lower melting point than simple inorganic salt, e.g., KCl and LiCl. When phenyltrifluoroborate ([PhBF3]−) and 1-ethyl-3-methylimidazolium ([C2mim]+) or 1-butyl-3-methylimidazolium ([C4mim]+) were combined, the resulting salts became a liquid state at room temperature. These ILs exhibited favorable viscosity and ionic conductivity comparable to a typical IL species, [C4mim][BF4].
Physical-Chemical Properties of Potassium Cryolite-Based Melts Containing KBF4
Authors: Tkacheva Olga , Kataev Alexander , Redkin Alexander , Rudenko Alexey , Dedyukhin Alexander , Zaikov Yurii
Published: September 2014

The KBF4 impact on the physical-chemical properties of the KF-AlF3 and KF-NaF(10 wt%)-AlF3 melts with cryolite ratio (CR) 1.3-1.5 was studied at temperatures 700-800 °C. The KBF4 additions (up to 15 mol.%) to the potassium-cryolite-based electrolytes increase the liquidus temperature and the alumina solubility, the latter provides enlarging the homogeneity range of the (cryolite-KBF4)-Al2O3 system. The boron-containing cryolites have density lower than that of boron-free electrolytes. The electrical conductivity of the KF-AlF3-KBF4 mixtures (CR=1.3) within the KBF4 concentration range 0-10 mol.% is practically constant.
Comparison of Redox Potentials in Non-Aqueous Solvents: Silver is Not a Noble Metal in the Acidic Ionic Liquid HmimBr
Authors: Pütz Katharina , Himmel Daniel , Radtke Valentin , Krossing Ingo
Published: September 2014

We recently introduced the concept of the Protoelectric Potential Map (PPM) which presents a new combined pH- and redox scale in an absolute sense.1,2 The two scales are thermodynamically well described and are based on the absolute chemical potential of the proton (m
abs(H+)) and the absolute chemical potential of the electron (m
abs (e-)) which at standard conditions are the standard Gibbs energy of solvation Dsolv
G°(H+,S) and Dsolv
G°(e–,S), resp. The PPM allows the quick comparison of redox potentials (reducities) and the pH values of any redox/acid-base system in any media which may lead to completely new insights and applications.
Aluminum Anodization in the Low-Melting LiAlBr4-NaAlCl4-KAlCl4 Molten Salt
Authors: Wang Chen , Hussey Charles L.
Published: September 2014

The density and viscosity of the LiAlBr4-NaAlCl4-KAlCl4 (3:5:2) molten salt were determined as a function of temperature. A Walden plot indicated decoupling between the absolute viscosity and molar conductance and suggested some degree of superionic behavior. The anodization of aluminum in this molten salt proceeds under mixed kinetic and mass-transport control at small anodic potentials. At more positive potentials, the anodization reaction transitions to a mass-transport-limited process controlled by the dissolution of a passive layer on the Al electrode.
Deposition and Dissolution of Lithium through Lithium Phosphorus Oxynitride Thin Film in Some Ionic Liquids
Authors: Furuya Ryota , Katayama Yasushi , Miura Takashi
Published: September 2014

Electrochemical deposition and dissolution of lithium were investigated in some aprotic ionic liquids through a typical inorganic Li ion conductor, lithium phosphorus oxynitride (LiPON) thin film. In 1-butyl-1-methylpyrrolidinium (BMP+) and 1-ethyl-3-methylimidazolium (EMI+) bis(trifluoromethylsulfonyl)amide (TFSA–) containing 1 M LiTFSA, no cathodic current attributable to reductive decomposition of the ionic liquids was observed on the Ni electrode coated with LiPON thin film. Electrochemical deposition and dissolution of Li was confirmed to occur through LiPON thin film in both ionic liquids. Therefore, LiPON thin film acted as an artificial solid electrolyte interphase film, in which Li ion was transported between the ionic liquids and LiPON thin film.
The Structure of Electrodeposited Aluminum Alloys from Chloroaluminate Ionic Liquids: Let’s Not Ignore the Temperature
Authors: Stafford Gery R. , Tsuda Tetsuya , Hussey Charles L.
Published: September 2014

Electrodeposited alloys are rarely in thermodynamic equilibrium, and several unique microstructural features such as extended solid solubility, metastable crystalline phases, and metallic glasses are generally observed. Because the excess free energy of the deposit is inversely proportional to the atomic mobility, phase constitution depends strongly on deposition temperature. This paper examines the influence of deposition temperature on the crystal structure of electrodeposited Al-Mn and Al-Ti alloys electrodeposited from AlCl3-NaCl and AlCl3-EMImCl ionic liquids from temperatures ranging from 80 °C to 425 °C. Deposition at low temperature favors the preferential deposition of amorphous and crystalline phases which appear as high temperature variants in the equilibrium phase diagram. These structures generally have high symmetry, and for this reason are relatively easy to nucleate. The room temperature equilibrium phases, which generally have a more complicated structure, can only be obtained at elevated deposition temperatures.
Separation of Dy from Nd-Fe-B Magnet Scraps Using Molten Salt Electrolysis
Authors: Konishi Hirokazu , Ono Hideki , Takeuchi Eiichi , Nohira Toshiyuki , Oishi Tetsuo
Published: September 2014

The alloy sample was prepared by cathodic potentiostatic electrolysis at 0.65 V (vs. Li+/Li) for 1 h using a Ni plate in a molten LiCl-KCl-DyCl3-NdCl3-PrCl3 system at 723 K. The mass ratio of Dy/Nd+Pr in the alloy sample was the highest, i.e., 50 at 0.65 V. Anodic potentiostatic electrolysis at 2.20 V for 12 h was conducted using the Nd-Fe-B magnet electrode in a molten LiCl-KCl system. The sample obtained at 2.20 V was almost dissolved, and the original form was disappeared. After anodic potentiostatic electrolysis at 2.20 V, cathodic potentiostatic electrolysis was conducted at 1.00 V for 5 h using a Mo plate in order to remove Fe dissolved in the bath. Finally, cathodic potentiostatic electrolysis was conducted at 0.67 V for 24 h using a Ni plate. The mass ratio of Dy/Nd in the alloy sample was found about 30 for 24 h.
Electrorefining Process for the Treatment of Zr-Alloy Cladding Hull Wastes from Used Nuclear Fuels
Authors: Lee Chang Hwa , Lee Yoo Lee , Jeon Min Ku , Choi Yong Taek , Kang Kweon Ho , Park Guen-Il , Park Kyung-Tae
Published: September 2014

The Zr electrorefining process in chloride-based molten salts is demonstrated for the purpose of cladding hull waste treatment. The addition of fluoride ions modifies the electrochemical behavior of Zr, resulting in a single-step reduction process. The morphological feature of electrorefined Zr in LiCl-KCl-LiF-ZrCl4 baths is revealed to be dendritic, compared to that in LiCl-KCl-ZrCl4 baths. The crystallinity of the recovered Zr is also enhanced by the addition of fluoride ions.
Nanomechanical Properties of Standard and Strained SOI Films Fabricated by Wafer Bonding and Layer Splitting
Authors: Mamun M A , Zhang Kai , Baumgart Helmut , Elmustafa A A
Published: September 2014

Biaxial tensile strained Si layers grown epitaxially on SiGe have attracted renewed attention for high performance CMOS devices. Strain engineering for mobility enhancement is an attractive option to improve CMOS device performance. Epitaxial Si1-xGex and most recently Ge-free bi-axially strained sSOI are among the serious candidates for higher mobility channel material. We demonstrate how the fabrication of thin single crystal Si devices by wafer bonding and hydrogen ion cut film exfoliation technique is affecting their nanomechanical properties compared to bulk single crystal Si. Although both the handle wafer and the bonded thin device layer are single crystal Si, it turns out that their nanomechanical properties differ considerably. Using nanoindentation, we measured the properties of SOI and bi-axially tensile strained sSOI and benchmarked the results against single crystal bulk Si. The experimental results indicate that the hardness of the strained thin Si films varies significantly.
(Invited) SOI-Type Bonded Structures for Advanced Technology Nodes
Authors: Widiez Julie , Hartmann Jean-Michel , Mazen Frédéric , Sollier Sébastien , Veytizou Christelle , Bogumilowicz Yann , Augendre Emmanuel , Martin Mickael , Gonzatti Frédéric , Roure Marie-Christine , Duvernay Julien , Loup Virginie , Euvrard-Colnat Catherine , Seignard Aurélien , Baron Thierry , Cipro Romain , Bassani Franck , Papon Anne-Marie , Guedj Cyril , Huyet Isabelle , Rivoire Maurice , Besson Pascal , Figuet Christophe , Schwarzenbach Walter , Delprat Daniel , Signamarcheix Thomas
Published: September 2014

Bulk silicon device technologies are reaching fundamental scaling limitations. The 28 nm and 22 nm technology nodes have seen the introduction of Ultra-Thin Body and Buried Oxide Fully Depleted SOI (UTBB-FDSOI) devices and FinFETs, respectively. Fully Depleted transistor technologies are mandatory to suppress short channel effects. Today, all major research and development alliances state that the silicon and its Fully Depleted transistor technologies have the potential to address roadmap requirements down to the 10nm node. Innovations will be necessary for lower, more advanced node (under 10nm). Specifications are to continue to ensure a good electrostatic control while providing excellent electrical performance. To meet these demands, several research areas (substrate engineering as well as multiple gate devices and 3D integration) will be involved in integrated circuit fabrication. This paper reports our latest achievements in SOI-type bonded substrates for advanced technology nodes.