bluuebunny/crossref_metadata_2025 huggingface dataset:
Absence of CD14 Delays Progression of Prion Diseases Accompanied by Increased Microglial Activation
Authors: Sakai Keiko , Hasebe Rie , Takahashi Yusuke , Song Chang-Hyun , Suzuki Akio , Yamasaki Takeshi , Horiuchi Motohiro
Published: October 2013

Prion diseases are fatal neurodegenerative disorders characterized by accumulation of PrPSc, vacuolation of neurons and neuropil, astrocytosis, and microglial activation. Upregulation of gene expressions of innate immunity-related factors, including complement factors and CD14, is observed in the brains of mice infected with prions even in the early stage of infections. When CD14 knockout (CD14−/−) mice were infected intracerebrally with the Chandler and Obihiro prion strains, the mice survived longer than wild-type (WT) mice, suggesting that CD14 influences the progression of the prion disease. Immunofluorescence staining that can distinguish normal prion protein from the disease-specific form of prion protein (PrPSc) revealed that deposition of PrPScwas delayed in CD14−/−mice compared with WT mice by the middle stage of the infection. Immunohistochemical staining with Iba1, a marker for activated microglia, showed an increased microglial activation in prion-infected CD14−/−mice compared to WT mice. Interestingly, accompanied by the increased microglial activation, anti-inflammatory cytokines interleukin-10 (IL-10) and transforming growth factor β (TGF-β) appeared to be expressed earlier in prion-infected CD14−/−mice. In contrast, IL-1β expression appeared to be reduced in the CD14−/−mice in the early stage of infection. Double immunofluorescence staining demonstrated that CD11b- and Iba1-positive microglia mainly produced the anti-inflammatory cytokines, suggesting anti-inflammatory status of microglia in the CD14−/−mice in the early stage of infection. These results imply that CD14 plays a role in the disease progression by suppressing anti-inflammatory responses in the brain in the early stage of infection.
Mutations in the Parainfluenza Virus 5 Fusion Protein Reveal Domains Important for Fusion Triggering and Metastability
Authors: Bose Sayantan , Heath Carissa M. , Shah Priya A. , Alayyoubi Maher , Jardetzky Theodore S. , Lamb Robert A.
Published: October 2013

Paramyxovirus membrane glycoproteins F (fusion protein) and HN, H, or G (attachment protein) are critical for virus entry, which occurs through fusion of viral and cellular envelopes. The F protein folds into a homotrimeric, metastable prefusion form that can be triggered by the attachment protein to undergo a series of structural rearrangements, ultimately folding into a stable postfusion form. In paramyxovirus-infected cells, the F protein is activated in the Golgi apparatus by cleavage adjacent to a hydrophobic fusion peptide that inserts into the target membrane, eventually bringing the membranes together by F refolding. However, it is not clear how the attachment protein, known as HN in parainfluenza virus 5 (PIV5), interacts with F and triggers F to initiate fusion. To understand the roles of various F protein domains in fusion triggering and metastability, single point mutations were introduced into the PIV5 F protein. By extensive study of F protein cleavage activation, surface expression, and energetics of fusion triggering, we found a role for an immunoglobulin-like (Ig-like) domain, where multiple hydrophobic residues on the PIV5 F protein may mediate F-HN interactions. Additionally, destabilizing mutations of PIV5 F that resulted in HN trigger-independent mutant F proteins were identified in a region along the border of F trimer subunits. The positions of the potential HN-interacting region and the region important for F stability in the lower part of the PIV5 F prefusion structure provide clues to the receptor-binding initiated, HN-mediated F trigger.
Occurrence of Guillain-Barré syndrome as an immune mediated complication after thrombolysis with streptokinase for acute anterior wall myocardial infarction: a caution to be vigilant
Authors: Kumar Basant , Agrawal Navin , Patra Soumya , Manjunath C N
Published: October 2013

Guillain-Barré syndrome (GBS) constitutes a heterogeneous group of immune-mediated peripheral neuropathic disorders that can be triggered by a variety of antecedent events. Clinical symptoms are thought to result from streptokinase antibody-mediated damage to the local blood–nerve barrier. We report the case of a 50-year-old man with acute anterior wall myocardial infarction who developed GBS as a manifestation of autoimmune hypersensitivity reaction to the drug 17 days after thrombolytic therapy with streptokinase. The patient was treated with a 5-day course of intravenous γ globulin and his symptoms improved and there was no residual deficit. The case forms a reminder of the autoimmune complications of non-fibrin specific agents that can sometimes be catastrophic and require persistent and vigilant in-hospital and immediate postdischarge follow-up and immediate management.
TOWARDS DETECTION OF LOW MASS WIMPs (MWIMP<10GeV/c2): MINI-REVIEW
Authors: DRUKIER A. K. , NUSSINOV S.
Published: October 2013

Weakly Interacting Massive Particles (WIMPs) may constitute most of the matter in the Universe. There are intriguing results from DAMA/LIBRA, CoGeNT and CRESST-II, and more recently CDMS-Si suggesting a relatively light dark matter candidate of mass <10 GeV /c2. At the same time, experiments using heavy nuclear targets such as CDMS-Ge and XENON detectors suggest that there is no DM candidates with MW>15 GeV /c2. We review the existing experiments and the problems associated with light mass WIMP detection. We find that all six experiments considered (DAMA, CoGeNT, CRESST, CDMS-Si, CDMS-Ge, XENON) are consistent if one assumes that the mass of WIMP is lower than expected: 3.4<MW<6.8 GeV /c2. This is followed by a discussion of the properties of "new" detectors, which may enable more reliable detection of low mass WIMPs.
SCALAR–PSEUDOSCALAR INTERACTIONS IN NEUTRINO–ELECTRON SCATTERING
Authors: GAITÁN R. , GARCES E. A. , MIRANDA O. G. , MONTES DE OCA Y J. H.
Published: October 2013

Many extensions to the Standard Model imply the existence of new charged scalar Higgs bosons. We study the contribution of a general scalar or pseudoscalar coupling for the neutrino–electron scattering. We take a phenomenological approach in order to obtain model independent limits to the couplings that arise in this picture. We illustrate the reach of the constraints by studying the particular case of the type III two Higgs doublet model, where we have found new constraints to some elements of the Yukawa couplings mixing matrix (|Yee| ≤ 1 × 10-1 and |Yeμ| ≤ 7 × 10-2 at 90% CL).
COHERENCE, ENERGY AND CHARGE TRANSFERS IN DE-EXCITATION PATHWAYS OF ELECTRONIC EXCITED STATE OF BIOMOLECULES IN PHOTOSYNTHESIS
Authors: BOHR HENRIK G. , MALIK F. BARY
Published: October 2013

The observed multiple de-excitation pathways of photo-absorbed electronic excited state in the peridinin–chlorophyll complex, involving both energy and charge transfers among its constituents, are analyzed using the bio-Auger (B-A) theory. It is also shown that the usually used Förster–Dexter theory, which does not allow for charge transfer, is a special case of B-A theory. The latter could, under appropriate circumstances, lead to excimers.
EVALUATING INFORMATION QUALITY AND VALIDITY OF VALUE LINE STOCK RATINGS USING DOMINATION CONES
Authors: WANG S. Y. , YU P. L.
Published: October 2013

Investment in stock market involves many decision criteria and variables; hence investors are increasingly relying on the ratings provided by rating agencies to guide their stock selections. However, do these stock ratings have information value? Are these agencies' ratings valid? We establish the dominance cone principle and use the Value Line stock ratings to demonstrate the application of the dominance principle. Our results based upon limited data show that the Value Line rating does not support the notion that better rating results in better rate of return during 2006–2007.
Interaction between TNFone and tetrapyrroles may account for their anti-genotoxic effects — a novel mechanism for DNA-protection
Authors: Mölzer Christine , Huber Hedwig , Steyrer Andrea , Ziesel Gesa V. , Wallner Marlies , Goncharova Iryna , Orlov Sergey , Urbanová Marie , Ahlfors Charles E. , Vítek Libor , Bulmer Andrew C. , Wagner Karl-Heinz
Published: October 2013

Bilirubin, the principal and biologically most relevant bile pigment was, until recently, considered a waste product of haem catabolism. However, current data suggest that bile pigments possess biological potential, related to their antioxidant and anti-mutagenic effects. In this context, it is now assumed that bile pigments and their derivatives exert these effects via multiple mechanisms, including discrete anti-oxidative and physico-chemical interactive effects. The major scientific focus so far has concentrated on the compounds' antioxidant action, and mechanistic investigations of possible mutagen-tetrapyrrole interaction are lacking. Therefore we tested structurally related bile pigments/derivatives (bilirubin/-ditaurate/-dimethyl ester, biliverdin/-dimethyl ester, urobilin, stercobilin and protoporphyrin) for anti-genotoxicity in the Salmonella reverse mutation assay (strains TA98, TA102), together with the synthetic mutagen 2,4,7-trinitro-9H-fluoren-9-one (TNFone). To explore possible structural interactions, molecular systems of chlorin e6 porphyrin/bilirubin/biliverdin with TNFone were assayed using circular dichroism. These data consistently revealed, at suprastoichiometric concentrations, that tetrapyrroles interact with TNFone. Addition of TNFone to chlorin e6 porphyrin, bilirubin-albumin and biliverdin-albumin led to a marked change in pigment spectra, providing evidence for tight tetrapyrrole-mutagen interaction. This conclusion was also supported by substantial, TNFone-induced decrease of bilirubin oxidation in the bilirubin-albumin system. This outcome was reflected in a bacterial model, in which most tetrapyrroles and especially protoporphyrin, significantly attenuated TNFone-induced mutagenesis. These data indicate that aromatic, tetrapyrrolic molecules interact with TNFone, providing a novel mechanism to suggest the anti-mutagenic effects of bile pigments in vivo are related to their physico-chemical interaction with genotoxins.
Design of efficient reversible logic-based binary and BCD adder circuits
Authors: Thapliyal Himanshu , Ranganathan Nagarajan
Published: October 2013

Reversible logic is gaining significance in the context of emerging technologies such as quantum computing since reversible circuits do not lose information during computation and there is one-to-one mapping between the inputs and outputs. In this work, we present a class of new designs for reversible binary and BCD adder circuits. The proposed designs are primarily optimized for the number of ancilla inputs and the number of garbage outputs and are designed for possible best values for the quantum cost and delay. In reversible circuits, in addition to the primary inputs, some constant input bits are used to realize different logic functions which are referred to as ancilla inputs and are overheads that need to be reduced. Further, the garbage outputs which do not contribute to any useful computations but are needed to maintain reversibility are also overheads that need to be reduced in reversible designs. First, we propose two new designs for the reversible ripple carry adder: (i) one with no input carry
c
0
and no ancilla input bits, and (ii) one with input carry
c
0
and no ancilla input bits. The proposed reversible ripple carry adder designs with no ancilla input bits have less quantum cost and logic depth (delay) compared to their existing counterparts in the literature. In these designs, the quantum cost and delay are reduced by deriving designs based on the reversible Peres gate and the TR gate. Next, four new designs for the reversible BCD adder are presented based on the following two approaches: (i) the addition is performed in binary mode and correction is applied to convert to BCD when required through detection and correction, and (ii) the addition is performed in binary mode and the result is always converted using a binary to BCD converter. The proposed reversible binary and BCD adders can be applied in a wide variety of digital signal processing applications and constitute important design components of reversible computing.
SECA Program Overview and Status
Authors: Vora Shailesh D
Published: October 2013

The overall objective of the Solid State Energy Conversion Alliance (SECA), a U.S. Department of Energy program coordinated and managed by the National Energy Technology Laboratory, is the development of advanced power generation system technology. Specifically, the systems being developed, for central-station (>100 MWe) application, and based on solid oxide fuel cell (SOFC) technology, are to be cost-effective and operate with high electric efficiency. Further, their designs must provide for effective carbon (CO2) capture, and they must restrict the emission of other pollutants (eg, Hg, NOx, SOx) and conserve water. Historically, the fuel basis for this development has been coal, our major domestic energy source. This continues to be the focus. However, the program is cognizant that the SOFC technology developed to meet design objectives could be adapted for implementation in advanced power generation systems fueled with natural gas. Thus, there could be strong synergy between efforts to develop advanced coal-fueled power generation, as in the SECA program, and any parallel effort by the program participants to develop natural gas-fueled distributed-generation SOFC power systems. A natural gas-fueled distributed power generation system could be first to the marketplace, which would provide early manufacturing and operational experience on large commercial scale that would benefit SOFC power system developments with both fuels. SECA program status is reviewed.
Recent Progress of SOFC Combined Cycle System with Segmented-In-Series Tubular Type Cell Stack at MHI
Authors: Kobayashi Yoshinori , Ando Yoshimasa , Nishiura Masanori , Kishizawa Hiroshi , Iwata Mitsuyoshi , Matake Norihisa , Tomida Kazuo
Published: October 2013

Solid oxide fuel cell (SOFC) triple combined cycle system, integrated with gas turbine (GT) and steam turbine (ST), is an ultimate fossil fuel electric power generation system with very high efficiency. In 2008, Mitsubishi Heavy Industries, Ltd. (MHI) operated the 200 kW-class SOFC micro gas turbine (MGT) hybrid system under commission of New Energy and Industrial Technology Development Organization (NEDO) and we could demonstrate 52.1%-LHV net power generation efficiency. Based on the successful achievement, MHI developed a more compact 250 kW-class SOFC-MGT hybrid system for the purpose of utilization of a hybrid system in the NEDO project scheduled from fiscal 2011 to 2012. Furthermore, we have started a development of fundamental technologies of SOFC-GT-ST triple combined cycle system that aims to achieve more than 70% of power generation efficiency. In this paper, latest results on the development of SOFC and the systems are described.
Hexis’ SOFC System Galileo 1000 N – Lab and Field Test Experiences
Authors: Mai Andreas , Iwanschitz Boris , Schuler J. Andreas , Denzler Roland , Nerlich Volker , Schuler Alexander
Published: October 2013

Galileo 1000 N is an SOFC-based micro-CHP system for single family homes. This contribution reports on the newest achievements in the lab on efficiency, durability and cyclability of SOFC stacks and complete micro-CHP systems. It also shows results of the field tests. Achievements are total efficiencies of 95% (LHV) and electrical efficiencies of around 35% (AC net, LHV). The longest system test had been running for more than 40 000 h. More recent tests have achieved power degradations below 1% per 1000 h and cycling tests have shown a tolerance against at least 20 on-off cycles. The contribution also reports on the next steps to market introduction of the Galileo 1000 N.
Comparative Experimental and Technical-Economical Evaluation of a 1kWel Vs. 2.5kWel Tubular SOFC System for Residential Applications
Authors: Boigues Muñoz Carlos , McPhail Stephen J. , Cinti Giovanni , Penchini Daniele , Polonara Fabio
Published: October 2013

In the frame of a common project on the development of prototype micro-cogeneration systems for household applications, ENEA and FCLAB have characterized a 1kWel and a 2.5kWel tubular-type SOFC technology-based unit respectively. Spanning the entire operational window of the two systems (within boundary conditions set by safe and durable operation, i.e. limitations on fuel utilization, oxygen-to-carbon ratio, stack and exhaust temperature profiles) the performance and efficiency characteristics of the two systems have been fully mapped. Thus, a technical-economical evaluation can take place for a calculated assessment of the optimal allocation of the two scales of systems.
Durability Verification of Residential SOFC CHP System
Authors: Suzuki Minoru , Takuwa Yuya , Inoue Shuichi , Higaki Katsuki
Published: October 2013

Osaka Gas started joint development of the residential SOFC CHP system with Kyocera in FY2004, and Aisin Seiki Co., Ltd. and Toyota Motor Corporation also took part in out development. Development for commercialization was completed at the end of the 2011 fiscal year, and product commercialization was started. Most significant issue for commercialization was durability.　 Osaka Gas has conducted durability verification of a large number and long time test for stacks, material, and SOFC generation units in order to establish 10 years life time. As these results, we judged that durability SOFC power generation unit which uses latest stack, hot module design, and control reached durability target.
Durability Testing of a Short SOFC Stack under Direct Internal Steam Reforming of Methane
Authors: Fu Qingxi , Freundt Pierre , Bomhard Jakob , Hauler Felix
Published: October 2013

One 5-cell SOFC stack has been tested under both hydrogen and direct internal steam reforming of methane for a total duration of 3200 hours. Electrochemical impedance spectroscopy has been used to monitor the evolution of internal resistances of all repeating units in the stack. It has been found that repeating units in the stack degraded two times faster under direct internal steam reforming of methane (6.7 - 14.4%/kh voltage degradation) than under H2 (2.3 - 4.0%/kh). In combination with impedance results, this indicates deterioration of the anode as the main cause of degradation for operation under CH4/H2O. The degradation process is at least partially reversible when changing the gas from CH4 to H2.
Evolution of SOFCpower’ Stack Performances
Authors: Modena Stefano , Ceschini Sergio , Contino Anna Rita , Bini Ruggero , Tognana Lorenzo , Bertoldi Massimo , Wuillemin Zacharie
Published: October 2013

An optimized stack design was developed by SOFCpower-HTceramix group since 2011 and validated in the pilot production level in early 2013, to be integrated into the HoTbox™ module which includes all other hot components, a compact and thermally efficient solution, mainly but not exclusively for µCHP applications. The proprietary planar stack has been tested under severe conditions, with several H2/N2 mixtures and several type of reformate for both natural gas and biogas, allowing high fuel utilization for high electrical efficiency, up to 70% under steam reforming of natural gas at 750°C and S/C ratio of 2, whit realistic current density (j>0,3 A/cm2) and single-pass configuration. The optimized stack demonstrated also very good robustness, surviving to more than 50 full thermal cycles from operation to ambient temperature, without significant degradation.
Proposal and Study on Optimum Operation of SOFC CGS with EV Charging Stand
Authors: Kamiko Hiroaki , Bando Toshiya , Ayshah Zaffirah , Tanaka Tadashi , Kakimoto Naoto , Inui Yoshitaka
Published: October 2013

Our research group proposes a solid oxide fuel cell (SOFC) co-generation system with charging stand for electric vehicle (EV) as one of new applications of SOFCs. To evaluate the feasibility of the proposed system, the total efficiency, energy saving rate and electricity available for EV charging are calculated by comparing the electric and thermal demands measured at the existing multifamily apartment with the numerically obtained electric and thermal energy supplied from the proposed system. In the comparisons, optimization of operating method of the SOFC is also investigated and taken into account. Through the calculations and optimization, it is made clear that the proposed system is useful with regard to both the energetic efficiency and energy-consuming pattern.
Current SOFC R&D Activities at CNR-ITAE
Authors: Lo Faro Massimiliano , Aricò Antonino S.
Published: October 2013

The CNR-ITAE has a long and proven experience in SOFCs having contributed to the penetration of this technology into Europe since the early 1980's. In this communication will be reported the CNR-ITAE experience in the electrochemical screening of SOFC components under practical operating conditions, electrochemical process optimization on a small scale, and ex-situ physico-chemical characterization of the SOFC cells after operation.
Development of Anode Off-Gas Recycle Blowers for High Efficiency SOFC Systems
Authors: Tanaka Yohei , Sato Kimihiko , Yamamoto Atsushi , Kato Tohru
Published: October 2013

Prototype of efficient anode-off gas recycle blowers was developed with a 3D turbo impeller and a DC brush-less built-in motor for high efficiency SOFCs. Performance test of the blowers clarified 26% and 52% total blower efficiency for the type SSR-70 for 10 kW-class SOFC and SSR-140 for 250 kW, respectively. System performance simulation of an SOFC system with the SSR-70 blower elucidated that 59% net AC electrical efficiency can be expected. When the blower efficiency is improved to 50% as of SSR-140, electrical efficiency will become 60%. We will continue developing more efficient recycle blowers.
Metal Supported Solid Oxide Fuel Cells: From Materials Development to Single Cell Performance and Durability Tests
Authors: Mougin Julie , Brevet Aude , Grenier Jean-Claude , Laucournet Richard , Larsson Per-Olof , Montinaro Dario , Rodriguez-Martinez Lide M , Alvarez Mario A , Stange Marit , Trombert Sandrine
Published: October 2013

Metal supported cells (MSC) are considered as the next generation of Solid Oxide Fuel Cells due to their robustness and cost-efficiency. However, improvement of their performances for operation below 700°C is a key point, as well as their durability and their manufacturing route. Within the RAMSES EU project, materials, components and processes have been tailored for MSCs. Thus, a metal substrate, with coating, has been optimized, fulfilling the targets of low-cost, sinterability in low-oxidizing atmosphere and oxidation resistance. A customized electrolyte powder allowed decreasing the sintering temperature of 100°C compared to a reference 8YSZ powder. A modified Ni-8YSZ anode as well as a nickelate cathode were found to reach low polarization resistances of respectively 0.37 and less than 0.20 Ohm.cm² at 600°C. The progressive implementation of these materials in MSC has led to improved performances in tubular MSC, with an ASR of 1.56 Ohm.cm² at 600°C. Durability over 500h and 500 thermal cycles have been successfully achieved.
Progress in Metal-Supported SOFCs Using Hydrogen and Methane Fuels
Authors: Kesler Olivera , Cuglietta Mark , Harris Jeffrey , Kuhn Joel , Marr Michael , Metcalfe Craig
Published: October 2013

Metal-supported SOFCs with power densities above 700 mW/cm2 at 750oC were fabricated by atmospheric plasma spraying, which can be readily automated and scaled for larger cell areas and production volumes, with no cell sintering requirement. Porous stainless steel substrates were dip-coated to protect against oxidation and chromium loss, followed by fabrication of the functional layers. Preliminary performance in hydrogen was found to be stable for 200 hours, with longer durability tests ongoing. Cells with modified anodes can achieve performances close to those of standard cells operating in hydrogen, with no evidence of coking in TGA methane experiments. Fabrication of anodes for hydrocarbon fuels and the results of scaling up from button cells to 5cm x 5cm cells are discussed.
Coating Developments for Metal-Supported Solid Oxide Fuel Cells
Authors: Stange Marit , Denonville Christelle , Larring Yngve , Haavik Camilla , Brevet Aude , Montani Alexandre , Sicardy Olivier , Mougin Julie , Larsson Per-Olof
Published: October 2013

Metal supported cells are considered the next generation of Solid Oxide Fuel Cells due to higher robustness and cost-efficiency. However, improvement of the low temperature performance (< 700°C), increased durability and the use of manufacturing routes compatible to the metal substrate are key parameters for success. Coatings for porous metal supports in order to improve the oxidation resistance of the metal, reduce the chromium evaporation and poisoning, and increase the conductivity of the protective oxide scale, are developed. The oxidation of coated and non-coated substrates in air and wet hydrogen has been compared and shows that it is possible to increase the oxidation resistance at 600°C in air by more than 10 and wet hydrogen by more than 1000 by coating the pre-sintered porous metal substrate.
Sulfur Poisoning of Ni/Stabilized-Zirconia Anodes – Effect on Long-Term Durability
Authors: Hauch Anne , Hagen Anke , Hjelm Johan , Ramos Tânia
Published: October 2013

Sulfur impurities in carbon containing fuels for solid oxide fuel cells (SOFC), e.g. natural gas and biogas, can lead to significant losses in performance due to the sulfur sensitivity of Ni/YSZ SOFC anodes. Full cells having Ni/YSZ and Ni/ScYSZ anodes have been characterized during long-term galvanostatic operation in internal reforming gas mixture (CH4/H2O/H2:30/60/10), with 2 ppm H2S exposure to the anode, at different current densities. The aim was not only to investigate the well-known initial performance drop associated with adsorbed sulfur in the Ni/stabilized-zirconia anodes, but also to focus on the long-term effect over a few hundred of hours. This work describes and correlates the observed evolution of anode performance, over hundreds of hours, with sulfur poisoning with the different operating conditions.
Redox-Stability of a Planar Metal-Supported SOFC
Authors: Roehrens Daniel , Büchler Oliver , Sebold Doris , Kappertz Mark , Schafbauer Wolfgang , Franco Thomas , Menzler Norbert H. , Buchkremer Hans Peter
Published: October 2013

We report on the systematic examination of the redox behavior of a novel metal-supported SOFC cell type based on a porous Cr/Fe support and a thin YSZ-electrolyte layer applied by PVD methods. The oxidation of the Ni catalyst at the anode and the subsequent damage to the fuel cell microstructure is one of the main contributions to degradation of an SOFC. Our cell concept was tested for tolerance to cyclic oxidation and reduction of the anode, employing gravimetric and electron microscopy methods. The effects of redox cycling on the microstructure are examined and compared to corresponding results from state-of-the-art anode-supported SOFCs.
Synthesis of Half Fuel Cell Ni-YSZ / YSZ on Porous Metallic Support by Dry Surface Deposition Processes
Authors: Fondard Jérémie , Bertrand Pierre , Billard Alain , Skrabs Stefan , Franco Thomas , Bertrand Ghislaine , Briois Pascal
Published: October 2013

A new cell design with metallic porous support was selected in order to face with the reduction of IT-SOFC’s operation temperature. Nevertheless, the excessive roughness of the porous metallic interconnect induce additional problems when a thin electrolyte layer is required. In this work, an anode material (NiO-TSZ) by Atmospheric Plasma Spraying was deposited on metallic supports (ITM) produced by PLANSEE able to cover the roughness of the support. Then, a second thin and dense electrolyte layer (YSZ) by reactive magnetron sputtering was produced on the anode material. In this study, for both processing routes, the optimal process parameters regarding the structural, morphological and electrical characterizations were investigated.
X-ray Computed Tomography Investigation of Mechanical Behavior of Anode-Supported SOFCs during the Redox Cycle Using X-ray CT Method
Authors: Kushi Takuto , Fujita Kenjiro
Published: October 2013

The mechanical behavior of an anode-supported cell during reoxidation at high temperature was investigated using an X-ray computed tomography (CT) method. During reoxidation with no seal, warping of the anode-supported cell increased and a critical crack was seen at 1023 K in the CT images. The mechanical behavior and open-circuit voltage (OCV) of the cell with a seal during reoxidation was also investigated. In the CT images, cracks were found in the electrolyte at 1023 K during reduction. The OCV decreased during reduction, and the value was unstable after the crack generation.
Current Distribution Measurement of a Microtubular Solid Oxide Fuel Cell
Authors: Shimizu Akira , Nakajima Hironori , Kitahara Tatsumi
Published: October 2013

Fuel starvation in the downstream part of the flow channel in a solid oxide fuel cell decays the cell performance giving rise to current distribution. In particular, this behavior is complicated in the case of the hydrocarbon fuel. Elucidation of the current distribution is therefore required to optimize the gas flow condition under operation, and to develop new cell design and diagnosis method for the distribution. We have thus measured the current distribution in an anode-supported microtubular cell with segmented cathodes under different fuel flow rates at around 800℃.
Integration of Innovative Oxide Materials in an Intermediate Temperature Solid Oxide Fuel Cell
Authors: Morandi Anne , Fu Qingxi , Marrony Mathieu , Bassat Jean-Marc , Joubert Olivier
Published: October 2013

This work aims to associate two innovative promising oxide materials, the perovskite-type BaIn0.3Ti0.7O3-δ (BIT07) electrolyte and the lanthanide nickelate Pr2-xNiO4+δ
cathode, in a planar anode-supported SOFC for an efficient operation at 700°C. The cell elaboration protocol will be briefly described, and the results of electrochemical characterizations of complete cells will be discussed. Adding a GDC barrier layer in between BIT07 electrolyte and the cathode decreased the polarization resistance by a factor 4, e.g. for Pr1.97NiO4+δ a competitive value of 0.29 Ω cm² is reached. It also led to increased OCV values, as a small p-type conductivity of BIT07 in oxidizing atmosphere associated with a few microscopic cracks observed in the electrolyte layer could be compensated by an electron-blocking effect of GDC and a filling of the porosities of the electrolyte. This cell was operated beyond 500 hours of under current, with a fairly high extrapolated degradation rate of 27% / kh.
Durability of SOFCs Using Inexpensive Ca-Doped ZrO2 Electrolytes
Authors: Toyofuku Yasuhiro , Hosoi Takami , Kawabata Tsutomu , Shiratori Yusuke , Taniguchi Shunsuke , Sasaki Kazunari
Published: October 2013

For the further commercialization of SOFCs, the cost reduction for materials is one of the most important technological issues. Currently, Y or Sc is widely used as a dopant of zirconia-based electrolytes, but these rare-earth elements are relatively expensive. In this study, we have examined the possibility to use Ca as an alternative dopant since it is abundant in the earth and inexpensive. We have experimentally found that Ca diffusion is relatively fast, causing cell performance degradation. Even so, such fast diffusion could be depressed by decreasing the concentration gradient of Ca dopant, leading to an improvement in the durability.
Optimization of Ceramic Composites in Solid Oxide Fuel Cells by Hierarchical Functional Architecturing of Powder Packing Structure
Authors: Lee Hae-Weon , Yoon Kyung Joong , Son Ji-Won , Lee Jong-Ho , Kim Byung-Kook , Je Hae-June
Published: October 2013

Solid oxide fuel cell is a composite of composites, and goes through a series of composite processing. SOFC always experience extensive constrained sintering in co-firing and post-firing due to shrinkage mismatches. Even though constraints are internal, external, or in combination, SOFCs suffer from critical flaws without optimization of constrained sintering. Thus it is necessary to understand the effects of internal and external constraints on sintering and microstructure development. In this study, we present examples and mechanistic explanation in which critical process flaws were suppressed by hierarchical functional control of the powder packing structure in the viewpoint of constrained sintering.
Y0.08Sr0.88TiO3-CeO2 Composite as a Diffusion Barrier Layer of STS-Supported SOFC
Authors: Kim Kun Joong , Kim Sun Jae , Choi Gyeong Man
Published: October 2013

Metal-supported SOFC (MS-SOFC) is promising for use at intermediate temperature range (500-700°C) since metal could provide the good thermal conductivity and the mechanical strength in addition to the low cost. The MS-SOFCs are often fabricated by co-firing of in reducing atmosphere to avoid metal oxidation. However, the inter-diffusion between Fe/Cr in stainless steel (STS) and Ni in the anode is detrimental to the electrochemical performance of the cell. In this study, Y0.08Sr0.88TiO3-CeO2 composite was used as a diffusion barrier layer (DBL). The effect of DBL and the cell performance will be discussed.
Multilayered Electrolyte-Supported SOFC Based on NEVZ-Ceramics Membrane
Authors: Burmistrov Ilya , Agarkov Dmitrii , Bredikhin Sergey , Nepochatov Yurii , Tiunova Olga , Zadorozhnaya Olga
Published: October 2013

SOFC batteries development is currently thriving in Russia (1). TVEL Fuel Company is a division of Rosatom State Corporation that promotes the SOFC technological platform, including cell, stacks, and integrated stack module for different applications. The technology development is based on R&D consortium between Institute of Solid State Physics Russian Academy of Sciences (ISSP RAS) with NEVZ-Ceramics (Novosibirsk, Russia) and includes materials synthesis and cost effective ceramic manufacturing methods for electrolyte supported flat cells with multilayered electrodes assembling for stack with metallic interconnectors from stainless steel Crofer 22H. Here we report on manufacturing and electrochemical tests of multilayered electrolyte-supported SOFC based on NEVZ-ceramics membrane. 10Sc1CeSZ membranes of 50x50 mm2 area and 250 microns thick were chosen as a support. NiO-10Sc1CeSZ and (La0.8Sr0.2)0.95MnO3-10Sc1CeSZ multilayered electrodes were deposited by print-screen technique. Electrochemical tests in two-chamber cell were evaluated in wide temperature range (700-900oC) and different oxygen atmospheres.
Atomic Layer Deposition, a Key Technique for Processing Thin-Layered SOFC Materials - Case Of Epitaxial Thin Layers of CeO2 Catalyst
Authors: Marizy A. , Désaunay T. , Chery D. , Roussel P. , Ringuedé A. , Cassir Michel
Published: October 2013

Composition control, quality and scalability of Atomic Layer Deposition (ALD) - processed thin layers can be major assets to optimise Solid Oxide Fuel Cell (SOFC). One of the challenging areas, which researchers are currently faced with, is the processing of thin-layered electrode materials, or at least as interfaces to soften their interaction with the electrolyte, e.g. LaxSr1-xMnO3 and La1-xCaxMnO3. The feasibility of processing proton-conductive materials is under study. The input of ultrathin layers (micro-SOFCs) or interlayers, as diffusion barriers, protective films or catalysts has already shown the unique benefits of this technique. For instance, it has recently been shown that ceria epitaxial layers may improve their catalytic effect towards hydrogen reduction.
Proton Conduction Of SrZr0.95Y0.05O3-δ Thin Film Prepared By RF Magnetron Sputtering
Authors: Oda Asuka , Okumura T. , Higuchi Tohru
Published: October 2013

Proton conductor SrZr0.95Y0.05O3-δ thin films have been deposited on SrTiO3(100) substrates by RF magnetron sputtering. The as-deposited thin films exhibit highly a-axis orientation on the substrate. The lattice constant of a-axis decreases with increasing film thickness. The thin film consists of small grain and smooth surface. The proton conduction is observed in the low temperature region between 200 and 400 °C. Although the conductivity does not depend on the film thickness, the proton conductivity of the thin film is higher than that of bulk crystal. The above results may indicate that the proton conductivity is closely related with the lattice distortion and oxygen vacancies.
Electrical Properties of Ba3Ca1.18Nb1.82O9-δ
Proton-Conducting Electrolyte Prepared by a Combustion Method
Authors: Bi Lei , Traversa Enrico
Published: October 2013

Ba3Ca1.18Nb1.82O9-δ
(BCN18), regarded as a promising proton-conducting electrolyte material for solid oxide fuel cells, is usually synthesized by a solid-state reaction because of the limited choice of Nb precursors. This study presents a wet chemical route for preparing BCN18 powders that were then sintered into pellets. Electrochemical impedance spectroscopy studies indicated that BCN18 pellets show proton conductivity, since their total conductivity in wet air was significantly larger than that in dry air. However, a detailed analysis showed that only the BCN18 bulk behaves as a proton conductor, while its grain boundary conductivity did not increase in wet air.
Relationship between Electrical Properties and Stress Field in Solid Electrolyte Thin Films
Authors: Osawa Y. , Iguchi Fumitada , Shimizu Makoto , Yugami Hiroo
Published: October 2013

Stress in yttria stabilized zirconia (YSZ) thin films was controlled by using various substrates, which had different thermal expansion coefficient (TEC), and electrical properties of the films were measured to study the relationship between the stress filed and electrical properties. Thin films of YSZ were deposited by PLD method on Al2O3 and AlN substrates. Because TEC of YSZ is larger than that of the substrates, tensile stress field was introduced into the films at room temperature. Measured stress value by XRD was varied from 0.7 to 1.7 GPa at R.T. This value is significantly higher than literature value. However, the films also showed different lattice volume on the different substrates. Although electrical properties in the films showed different tendencies by the substrates, both stress field and lattice volume were different. Hence, stress dependence of electrical properties was not clearly observed.
Oxygen Nonstoichiometry of Ce0.6La0.4O2-δ
Authors: Sato Hiroki , Hashimoto Shin-ichi , Nakamura Takashi , Yashiro Keiji , Amezawa Koji , Kawada Tatsuya
Published: October 2013

Ce0.6La0.4O2
(40LDC) is considered as a material for the interlayer between Ni-cermet anodes and LaGaO3 based electrolytes in solid oxide fuel cells. The oxygen nonstoichiometry of 40LDC was measured as a function of oxygen partial pressure P(O2) and temperature by thermogravimetry. The decrease of weight due to the formation of oxygen vacancies was observed under low P(O2) conditions. The weight of 40LDC sample increased under humidified condition. Using the reaction rate equation of adsorption, the weight change was explained as the adsorption of H2O on the surface of 40LDC. The weight change without the influence of adsorption was calculated. The oxygen nonstoichiometry was derived and successfully simulated using regular solution model. The standard Gibbs free energy change of oxygen vacancy formation and interaction parameter between oxygen vacancy and 40LDC were estimated as fitting parameters.
c-Axis Oriented Apatite-Type Silicates as Solid Electrolytes
Authors: Ueda Keiichi , Mineshige Atsushi , Takahashi Hirokazu , Saito Atsushi , Daiko Yusuke , Yoshioka Hideki , Yazawa Tetsuo
Published: October 2013

The c-axis oriented apatite-type silicates were fabricated in simple ways: fabrication of melt-quenched glass and its crystallization. It was found that a degree of c-axis orientation was affected by many factors such as crystallization temperature and kind of powder materials, in which the precursor glass embedded during crystallization. The performance of a solid oxide fuel cell (SOFC) using the crystallization glass as an electrolyte was also investigated at temperatures of 600 to 800°C.
Improving the Performance of SOFC Anodes by Decorating Perovskite with Ni Nanoparticles
Authors: Boulfrad Samir , Cassidy Mark , Traversa Enrico , Irvine John T. S.
Published: October 2013

In this work (La0.75Sr0.25)0.97Cr0.5Mn0.5O3 (LSCM) perovskite powders were pre-coated with 5 wt% nickel and mixed with different amounts of CGO for testing as anode materials under 3% wet H2. By using scanning transmission electron microscopy (STEM) with X-ray energy dispersive spectroscopy (EDS), we demonstrated that Ni forms a solid solution in the perovkite phase under oxidizing atmosphere and exsolves in form of nanoparticles under reducing atmospheres. The presence of the catalyst nanoparticles led to a decrease in the anodic activation energy by half and thus the polarization resistance was dropped by 60% at 800¢ªC. The effect of CGO amount will be also discussed.
La(Sr)Fe(Mn)O3 Thin Film Anode for Improving Power Generating Property with Enhancing Electric Conductivity and Oxidation Activity
Authors: Ju Young-Wan , Ida Shintaro , Ishihara Tatsumi
Published: October 2013

Influences of the dense and thin film anode of LaFeO3 on the power generating property were investigated. For improving the anodic performance, mixed electric and oxygen ionic conductor La(Sr)Fe(Mn)O3 thin film anode was fabricated via pulsed laser deposition. The maximum power density was ca. 3.0 W/cm2 at 973 K and ca.0.16 W/cm2 at 673 K. The high power density of the cell was explained by the decreased anodic overpotential which is suggested the enhanced anodic activity. Therefore, the nano sized LSFM dense film described seems to work as a unique active anode.
H2 Oxidation on Doped Yttrium Chromites Anode of Solid Oxide Fuel Cell
Authors: Li Wenyuan , Gong Mingyang , Liu Xingbo
Published: October 2013

Doped yttrium chromites as potential anodes for SOFC are studied with respect to the electrode performance and anode reaction mechanisms. Both electrical conductivity and electrode performance of yttrium chromites have been enhanced after Ni doping. Electrochemical impedance spectra results indicate that charge transfer process at high frequency and surface adsorption/diffusion processes at low frequency domain can be the dominant anode reaction steps. Ni doping accelerates the surface processes and improves the charge transfer process probably by increasing the amount of adsorbed H on the electrode surface. A model of H2 oxidation reaction is proposed, revealing this dependence stems from the reaction between adsorbed H and the lattice oxygen.
Lithium Iron Oxide – An Anode Material for Intermediate Temperature Solid Oxide Fuel Cell
Authors: Muhl Thuy Thanh , Irvine John T. S.
Published: October 2013

LiFeO2 was investigated as an alternative anode material for the intermediate temperature solid oxide fuel cell. At 650°C in Argon with 5% H2, LFO exhibited good electronic conductivity of 5.1 Scm-1. Fuel cell testing of composite anode of 40 wt% LFO and 60 wt% GDC and cathode with 40 wt% La0.6Sr0.4CoO3 and 60 wt% GDC on Ce0.9Gd0.1O1.95 electrolyte-supported cell showed excellent performance at 625°C. In humidified H2 at 625°C, the cell had an OCV of 0.89V and an Rp of 0.28Ωcm2. It achieved a maximum power density of 136 mWcm-2.
Quantitative Analysis of SOFC Anode Microstructure Change During Redox Cycles
Authors: Shimura Takaaki , Shikazono Naoki
Published: October 2013

In the present study, correlation between solid oxide fuel cell anode microstructure and electrochemical performance during redox cycles was analyzed. Yttria stabilized zirconia electrolyte-support cell with nickel/yttria stabilized zirconia composite for anode and lanthanum strontium manganite /yttria stabilized zirconia for cathode was prepared and tested under 100 h discharge process with redox cycles. Redox treatment was basically conducted between every 20 h discharge process. In addition, 100 h discharge test without redox cycles was conducted for comparison. Focused ion beam -scanning electron microscopy (FIB-SEM) observation was conducted for reconstructing the three dimensional microstructures of the tested samples. Enhancement of cell performance after every redox cycles and faster degradation in the following discharge process were observed. However, accelerated degradation converged to normal rate within 20h. There was no evident effect of redox treatment on degradation ratio through 100 h discharge operation. From the three dimensional microstructure reconstruction, it is found that shape of nickel particle got thinner and complicated with redox cycles. From microstructural analysis, increase of nickel surface area and three phase boundary length density was found for anodes with 4 redox cycles, which is consistent with the electrochemical measurement result.
Effect of PH3 on Stability of LST Ceramic Anode in Coal Syngas
Authors: Chen Gang , Kishimoto Haruo , Yamaji Katsuhiko , Kuramoto Koji , Gong Mingyang , Liu Xingbo , Hackett Gregory , Gerdes Kirk , Horita Teruhisa
Published: October 2013

Stability of La substituted SrTiO3
anode in coal syngas fuel was investigated. La0.25Sr0.75TiO3 and (La0.25Sr0.75)0.9TiO3 pellets were annealed in simulated coal syngas with 1 ppm PH3 atmosphere at 900 oC for 100 hrs. Sr3(PO4)2 and TiO2 were observed on the surface of each sample after the exposure test. XRD and SEM/EDS results indicate that most Sr3(PO4)2 was formed on the surface of stoichiometric LST. Chemical stability of LST for PH3 was effectively improved by changing the A-site deficient composition.
The Mechanism of Ammonia Oxidation at Ni-Fe-SDC Anode in Ammonia-Fueled SOFCs
Authors: Akimoto Wataru , Saito Morihiro , Inaba Minoru , Yoshida Hiroyuki , Inagaki Toru
Published: October 2013

The mechanism for ammonia oxidation at Ni-Fe alloy/Sm-doped ceria (SDC) anode cermet was investigated under SOFC operating conditions in the temperature range of 973 to 1173 K. OCV and AC impedance analysis revealed that ammonia is directly oxidized at Ni-Fe/SDC anode, especially at lower temperatures. It was also found that the activity is determined by a balance between ammonia adsorption and nitrogen desorption on the catalyst, and the synergy effects of Ni and Fe improved the activity of Ni-Fe alloy catalysts for ammonia oxidation.
Impact of Chemical Composition of Strontium-Doped Lanthanum Manganite Cathode on Microstructural Change and Performance During Long-Term Operation of SOFCs
Authors: Matsui Toshiaki , Mikami Yuichi , Muroyama Hiroki , Eguchi Koichi
Published: October 2013

The cells composed of strontium-doped lanthanum manganite (LSM) cathode and yttria-stabilized zirconia (YSZ) electrolyte show time-dependent events, such as the performance enhancement and/or deterioration, under polarized states. In this study, the influence of LSM composition on the microstructure of LSM/YSZ interface as well as electrochemical properties during prolonged operation was investigated. LSM cathodes with three different compositions were used and the microstructural change was evaluated quantitatively by a focused ion beam–scanning electron microscope (FIB–SEM). It was clarified that for LSMs with A-site deficient compositions, the change in TPB-length had a minor contribution to the performance enhancement upon the initial cathodic current passage. Furthermore, after 100 h of discharge the thin layer of LSM was formed over YSZ electrolyte, accompanied with an increase in cathode overpotential. These phenomena are strongly correlated with the change in oxygen nonstoichiometry of LSM under polarized states.