Prediction of solid oxide fuel cell cathode activity with first-principles descriptors

DEFF Research Database (Denmark)

Lee, Yueh-Lin; Kleis, Jesper; Rossmeisl, Jan

2011-01-01

In this work we demonstrate that the experimentally measured area specific resistance and oxygen surface exchange of solid oxide fuel cell cathode perovskites are strongly correlated with the first-principles calculated oxygen p-band center and vacancy formation energy. These quantities...... are therefore descriptors of catalytic activity that can be used in the first-principles design of new SOFC cathodes....

Mathematical micro-model of a solid oxide fuel cell composite cathode

International Nuclear Information System (INIS)

Kenney, B.; Karan, K.

2004-01-01

In a solid oxide fuel cell (SOFC), the cathode processes account for a majority of the overall electrochemical losses. A composite cathode comprising a mixture of ion-conducting electrolyte and electron-conducting electro-catalyst can help minimize cathode losses provided microstructural parameters such as particle-size, composition, and porosity are optimized. The cost of composite cathode research can be greatly reduced by incorporating mathematical models into the development cycle. Incorporated with reliable experimental data, it is possible to conduct a parametric study using a model and the predicted results can be used as guides for component design. Many electrode models treat the cathode process simplistically by considering only the charge-transfer reaction for low overpotentials or the gas-diffusion at high overpotentials. Further, in these models an average property of the cathode internal microstructure is assumed. This paper will outline the development of a 1-dimensional SOFC composite cathode micro-model and the experimental procedures for obtaining accurate parameter estimates. The micro-model considers the details of the cathode microstructure such as porosity, composition and particle-size of the ionic and electronic phases, and their interrelationship to the charge-transfer reaction and mass transport processes. The micro-model will be validated against experimental data to determine its usefulness for performance prediction. (author)

Study on the vibrational scraping of uranium product from a solid cathode of electrorefiner

Energy Technology Data Exchange (ETDEWEB)

Park, Sung Bin; Kang, Young Ho; Hwang, Sung Chan; Lee, Han Soo; Paek, Seung Woo; Ahn, Do Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-12-15

A high-throughput electrorefiner has been developed for commercialization use by enhancing the uranium recovery from the reduced metal which is produced from the oxide reduction process. It is necessary to scrap and effectively collect uranium dendrites from the surface of the solid cathode for high yield. When a steel electrode is used as the cathode in the electrorefining process, uranium is deposited and regularly stuck to the steel cathode during electrorefining. The sticking coefficient of a steel cathode is very high. In order to decrease the sticking coefficient of the steel cathode effectively, vibration mode was applied to the electrode in this study. Uranium dendrites were scraped and fell apart from the steel cathode by a vibration force. The vibrational scraping of the steel cathode was compared to the self-scraping of the graphite cathode. Effects of the applied current density and the vibration stroke on the scraping of the uranium dendrites were also investigated.

Solid oxide fuel cells having porous cathodes infiltrated with oxygen-reducing catalysts

Science.gov (United States)

Liu, Meilin; Liu, Ze; Liu, Mingfei; Nie, Lifang; Mebane, David Spencer; Wilson, Lane Curtis; Surdoval, Wayne

2014-08-12

Solid-oxide fuel cells include an electrolyte and an anode electrically coupled to a first surface of the electrolyte. A cathode is provided, which is electrically coupled to a second surface of the electrolyte. The cathode includes a porous backbone having a porosity in a range from about 20% to about 70%. The porous backbone contains a mixed ionic-electronic conductor (MIEC) of a first material infiltrated with an oxygen-reducing catalyst of a second material different from the first material.

Effect of cathode gas humidification on performance and durability of Solid Oxide Fuel Cells

DEFF Research Database (Denmark)

Nielsen, Jimmi; Hagen, Anke; Liu, Yi-Lin

2010-01-01

The effect of cathode inlet gas humidification was studied on single anode supported Solid Oxide Fuel Cells (SOFC's). The studied cells were Risø 2 G and 2.5 G. The former consists of a LSM:YSZ composite cathode, while the latter consists of a LSCF:CGO composite cathode on a CGO protection layer....... The humidification effect was found to be dependent on both the degree of humidification and the cathode polarization. No significant effect of humidification was found at OCV which rules out the possibility of a traditional poisoning effect with a blocking of active sites. Post-mortem high resolution FEG......-SEM analysis showed clear changes at and around the cathode/electrolyte contact area. In contrast to Risø 2 G cells, a very high tolerance towards humidification of cathode gas air was observed for Risø 2.5 G cells with no detectable effect of humidification even when the humidification was as high as 12.8 mol%...

Investigation of electrorefining of metallic alloy fuel onto solid Al cathodes

International Nuclear Information System (INIS)

Cassayre, L.; Malmbeck, R.; Masset, P.; Rebizant, J.; Serp, J.; Soucek, P.; Glatz, J.-P.

2007-01-01

This work concerned the electrorefining of UZr and UPuZr alloys on a solid aluminium cathode, in the LiCl-KCl eutectic melt containing U 3+ , Pu 3+ , Np 3+ , Zr 2+ or Zr 4+ , Am 3+ , Nd 3+ , Y 3+ , Ce 3+ and Gd 3+ chlorides. During constant current electrolyses, the use of a cathodic cut-off potential (-1.25 V versus Ag/AgCl) allowed to selectively deposit actinides (mainly U), while lanthanides remained in the salt. The aim was to determine the maximal load achievable on a single aluminium electrode. The total exchange charge was 4300 C, which represents the deposition of 3.72 g of actinides in 4.17 g Al, yielding a composition of 44.6 wt% An in Al. It was shown that the melting of the cathode contributed to increase the total amount of actinides deposited on the aluminium

Analytical, 1-Dimensional Impedance Model of a Composite Solid Oxide Fuel Cell Cathode

DEFF Research Database (Denmark)

Mortensen, Jakob Egeberg; Søgaard, Martin; Jacobsen, Torben

2014-01-01

An analytical, 1-dimensional impedance model for a composite solid oxide fuel cell cathode is derived. It includes geometrical parameters of the cathode, e.g., the internal surface area and the electrode thickness, and also material parameters, e.g., the surface reaction rate and the vacancy...... diffusion coefficient. The model is successfully applied to a total of 42 impedance spectra, obtained in the temperature range 555°C–852°C and in the oxygen partial pressure range 0.028 atm–1.00 atm for a cathode consisting of a 50/50 wt% mixture of (La0.6Sr0.4)0.99CoO3 − δ and Ce0.9Gd0.1O1.95 − δ...... and providing both qualitative and quantitative information on the evolution of the impedance spectra of cathodes with changing parameters....

Elaboration and characterisation of functionally graded cathodes for solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Simonet, J.; Kapelski, G.; Bouvard, D. [Laboratoire de Genie Physique et Mecanique des Materiaux, Institut National Polytechnique de Grenoble, CNRS UMR 5010, BP 46, 38042 Saint Martin d' Heres cedex (France)

2005-07-01

The industrial development of solid oxide fuel cells (SOFC) requires decreasing their operating temperature from 1000 deg. C to 700 deg. C while keeping acceptable mechanical and electrochemical performances. A solution consists in designing composite bulk cathodes with numerous electro-chemical reaction sites. The fabrication of such cathodes has been investigated with classical materials as lanthanum strontium manganese (LSM) and yttrium stabilized zirconia (YSZ), which is also the constitutive material of the electrolyte. A composite cathode with continuous composition gradient has been obtained by co-sedimentation of the powders in a liquid and subsequent firing. The obtained composition is investigated with Scanning Electron Microscope (SEM) and Electron Dispersive Spectrometry (EDS). It is found to be in good agreement with the prediction of a numerical model of the sedimentation process. (authors)

Rechargeable membraneless glucose biobattery: Towards solid-state cathodes for implantable enzymatic devices

Science.gov (United States)

Yazdi, Alireza Ahmadian; Preite, Roberto; Milton, Ross D.; Hickey, David P.; Minteer, Shelley D.; Xu, Jie

2017-03-01

Enzymatic biobatteries can be implanted in living organisms to exploit the chemical energy stored in physiological fluids. Generally, commonly-used electron donors (such as sugars) are ubiquitous in physiological environments, while electron acceptors such as oxygen are limited due to many factors including solubility, temperature, and pressure. The wide range of solid-state cathodes, however, may replace the need for oxygen breathing electrodes and serve in enzymatic biobatteries for implantable devices. Here, we have fabricated a glucose biobattery suitable for in vivo applications employing a glucose oxidase (GOx) anode coupled to a solid-state Prussian Blue (PB) thin-film cathode. PB is a non-toxic material and its electrochemistry enables fast regeneration if used in a secondary cell. This novel biobattery can effectively operate in a membraneless architecture as PB can reduce the peroxide produced by some oxidase enzymes. The resulting biobattery delivers a maximum power and current density of 44 μW cm-2 and 0.9 mA cm-2 , respectively, which is ca. 37% and 180% higher than an equivalent enzymatic fuel cell equipped with a bilirubin oxidase cathode. Moreover, the biobattery demonstrated a stable performance over 20 cycles of charging and discharging periods with only ca. 3% loss of operating voltage.

Composite cathode based on yttria stabilized bismuth oxide for low-temperature solid oxide fuel cells

International Nuclear Information System (INIS)

Xia Changrong; Zhang Yuelan; Liu Meilin

2003-01-01

Composites consisting of silver and yttria stabilized bismuth oxide (YSB) have been investigated as cathodes for low-temperature honeycomb solid oxide fuel cells with stabilized zirconia as electrolytes. At 600 deg. C, the interfacial polarization resistances of a porous YSB-Ag cathode is about 0.3 Ω cm 2 , more than one order of magnitude smaller than those of other reported cathodes on stabilized zirconia. For example, the interfacial resistances of a traditional YSZ-lanthanum maganites composite cathode is about 11.4 Ω cm 2 at 600 deg. C. Impedance analysis indicated that the performance of an YSB-Ag composite cathode fired at 850 deg. C for 2 h is severely limited by gas transport due to insufficient porosity. The high performance of the YSB-Ag cathodes is very encouraging for developing honeycomb fuel cells to be operated at temperatures below 600 deg. C

Investigation of electrorefining of metallic alloy fuel onto solid Al cathodes

Energy Technology Data Exchange (ETDEWEB)

Cassayre, L. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. 2340, 76125 Karlsruhe (Germany); Malmbeck, R. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. 2340, 76125 Karlsruhe (Germany)]. E-mail: rikard.malmbeck@cec.eu.int; Masset, P. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. 2340, 76125 Karlsruhe (Germany); Rebizant, J. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. 2340, 76125 Karlsruhe (Germany); Serp, J. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. 2340, 76125 Karlsruhe (Germany); Soucek, P. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. 2340, 76125 Karlsruhe (Germany); Glatz, J.-P. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. 2340, 76125 Karlsruhe (Germany)

2007-01-15

This work concerned the electrorefining of UZr and UPuZr alloys on a solid aluminium cathode, in the LiCl-KCl eutectic melt containing U{sup 3+}, Pu{sup 3+}, Np{sup 3+}, Zr{sup 2+} or Zr{sup 4+}, Am{sup 3+}, Nd{sup 3+}, Y{sup 3+}, Ce{sup 3+} and Gd{sup 3+} chlorides. During constant current electrolyses, the use of a cathodic cut-off potential (-1.25 V versus Ag/AgCl) allowed to selectively deposit actinides (mainly U), while lanthanides remained in the salt. The aim was to determine the maximal load achievable on a single aluminium electrode. The total exchange charge was 4300 C, which represents the deposition of 3.72 g of actinides in 4.17 g Al, yielding a composition of 44.6 wt% An in Al. It was shown that the melting of the cathode contributed to increase the total amount of actinides deposited on the aluminium.

Electrotransport of Uranium from a Liquid Cadmium Anode to a Solid Cathode

International Nuclear Information System (INIS)

Ahluwalia, Rajesh K.; Hua, Thanh Q.

2002-01-01

During anodic dissolution of irradiated binary Experimental Breeder Reactor-II fuel, a portion of the electrorefined uranium collects in the underlying cadmium pool. It is periodically recovered by setting up a cell configuration in which the pool is made the anode and uranium is electrodeposited on a solid cathode mandrel. A theoretical model is used to determine the current structure of the liquid cadmium anode. The model is validated by comparing against the measured composition of the cathode deposits. Multinodal simulations are conducted to explain the bell shape of deposits observed with this mode of electrotransport. The simulations also determine the dependence of collection efficiency on the electrical charge passed that is functionally consistent with the experimental data. Finally, a simplified operating map of the electrorefiner is presented that can be used to determine the conditions for growing cathode deposits of target composition

Asymmetric battery having a semi-solid cathode and high energy density anode

Energy Technology Data Exchange (ETDEWEB)

Tan, Taison; Chiang, Yet-Ming; Ota, Naoki; Wilder, Throop; Duduta, Mihai

2017-11-28

Embodiments described herein relate generally to devices, systems and methods of producing high energy density batteries having a semi-solid cathode that is thicker than the anode. An electrochemical cell can include a positive electrode current collector, a negative electrode current collector and an ion-permeable membrane disposed between the positive electrode current collector and the negative electrode current collector. The ion-permeable membrane is spaced a first distance from the positive electrode current collector and at least partially defines a positive electroactive zone. The ion-permeable membrane is spaced a second distance from the negative electrode current collector and at least partially defines a negative electroactive zone. The second distance is less than the first distance. A semi-solid cathode that includes a suspension of an active material and a conductive material in a non-aqueous liquid electrolyte is disposed in the positive electroactive zone, and an anode is disposed in the negative electroactive zone.

Properties of Copper Doped Neodymium Nickelate Oxide as Cathode Material for Solid Oxide Fuel Cells

Directory of Open Access Journals (Sweden)

Lee Kyoung-Jin

2016-06-01

Full Text Available Mixed ionic and electronic conducting K2NiF4-type oxide, Nd2Ni1-xCuxO4+δ (x=0~1 powders were synthesized by solid state reaction technique and solid oxide fuel cells consisting of a Nd2Ni1-xCuxO4+δ cathode, a Ni-YSZ anode and ScSZ as an electrolyte were fabricated. The effect of copper substitution for nickel on the electrical and electrochemical properties was examined. Small amount of copper doping (x=0.2 resulted in the increased electrical conductivity and decreased polarization resistance. It appears that this phenomenon was associated with the high mean valence of nickel and copper and the resulting excess oxygen (δ. It was found that power densities of the cell with the Nd2Ni1-xCuxO4+δ (x=0.1 and 0.2 cathode were higher than that of the cell with the Nd2NiO4+δ cathode.

Redox-reversible perovskite ferrite cathode for high temperature solid oxide steam electrolyser

International Nuclear Information System (INIS)

Li, Zhe; Li, Shisong; Tseng, Chung-Jen; Tao, Shanwen; Xie, Kui

2017-01-01

Highlights: • Redox reversible ferrite cathode is demonstrated for solid oxide electrolyser. • Promising electrical conductivity is obtained with Pr doping in hydrogen. • High performance of steam electrolysis is achieved with ferrite cathode. - Abstract: In this work, perovskite Sr 1−x Pr x FeO 3-δ (SPF) (x = 0.02, 0.04, 0.06, 0.08 and 0.10) are investigated and employed as solid oxide steam electrolyser cathode at 800 °C. X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscopy (TEM) analysis together indicate that the Sr 1−x Pr x FeO 3-δ is redox reversible with a phase transition from cubic to orthorhombic structure in redox cycles. The doping of Pr in A site has remarkably enhanced the electronic conduction to 1.0–1.2 S cm −1 at intermediate temperatures in reducing atmosphere. Electrochemical measurements demonstrate that the polarization resistance with Sr 0.96 Pr 0.04 FeO 3-δ electrode shows the lowest values of 0.25 Ω cm 2 in symmetric cells in reducing atmosphere at 800 °C. Direct steam electrolysis with Sr 0.96 Pr 0.04 FeO 3-δ cathode shows a current density of 1.64 A cm −2 at 2.0 V when fed with 5%H 2 O/Ar. The hydrogen production rate reaches 4.73, 6.68, 8.35 and 10.23 mL min −1 cm −2 at 1.4, 1.6, 1.8, 2.0 V, respectively, while the highest Faraday efficiency is as high as 97.16% at 1.8 V.

Fabrication and characterization of a cathode-supported tubular solid oxide fuel cell

Energy Technology Data Exchange (ETDEWEB)

Zhao, Chunhua; Liu, Renzhu; Wang, Shaorong; Wang, Zhenrong; Qian, Jiqin; Wen, Tinglian [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

2009-07-15

A cathode-supported tubular solid oxide fuel cell (CTSOFC) with the length of 6.0 cm and outside diameter of 1.0 cm has been successfully fabricated via dip-coating and co-sintering techniques. A crack-free electrolyte film with a thickness of {proportional_to}14 {mu}m was obtained by co-firing of cathode/cathode active layer/electrolyte/anode at 1250 C. The relative low densifying temperature for electrolyte was attributed to the large shrinkage of the green tubular which assisted the densification of electrolyte. The assembled cell was electrochemically characterized with humidified H{sub 2} as fuel and O{sub 2} as oxidant. The open circuit voltages (OCV) were 1.1, 1.08 and 1.06 V at 750, 800 and 850 C, respectively, with the maximum power densities of 157, 272 and 358 mW cm{sup -2} at corresponding temperatures. (author)

Thermodynamic and exergoeconomic analysis of biogas fed solid oxide fuel cell power plants emphasizing on anode and cathode recycling: A comparative study

International Nuclear Information System (INIS)

Mehr, A.S.; Mahmoudi, S.M.S.; Yari, M.; Chitsaz, A.

2015-01-01

Highlights: • Four biogas-fed solid oxide fuel cell power plants are proposed. • Performance of systems is compared with each other economically. • Efficiency of biogas fed fuel cell with anode–cathode recycling is the highest. • For current density of 6000 A/m"2 the optimum anode recycle ratio is around 0.25. • Unit product cost of biogas fed fuel cell with anode–cathode recycling is 19.07$/GJ. - Abstract: Four different configurations of natural gas and biogas fed solid oxide fuel cell are proposed and analyzed thermoeconomically, focusing on the influence of anode and/or cathode gas recycling. It is observed that the net output power is maximized at an optimum current density the value of which is lowered as the methane concentration in the biogas is decreased. Results indicate that when the current density is low, there is an optimum anode recycling ratio at which the thermal efficiency is maximized. In addition, an increase in the anode recycling ratio increases the unit product cost of the system while an increase in the cathode recycling ratio has a revers effect. For the same working conditions, the solid oxide fuel cell with anode and cathode recycling is superior to the other configurations and its thermal efficiency is calculated as 46.09% being 6.81% higher than that of the simple solid oxide fuel cell fed by natural gas. The unit product cost of the solid oxide fuel cell-anode and cathode recycling system is calculated as 19.07$/GJ which is about 35% lower than the corresponding value for the simple natural gas fed solid oxide fuel cell system.

Atmospheric Plasma Spraying Low-Temperature Cathode Materials for Solid Oxide Fuel Cells

Science.gov (United States)

Harris, J.; Kesler, O.

2010-01-01

Atmospheric plasma spraying (APS) is attractive for manufacturing solid oxide fuel cells (SOFCs) because it allows functional layers to be built rapidly with controlled microstructures. The technique allows SOFCs that operate at low temperatures (500-700 °C) to be fabricated by spraying directly onto robust and inexpensive metallic supports. However, standard cathode materials used in commercial SOFCs exhibit high polarization resistances at low operating temperatures. Therefore, alternative cathode materials with high performance at low temperatures are essential to facilitate the use of metallic supports. Coatings of lanthanum strontium cobalt ferrite (LSCF) were fabricated on steel substrates using axial-injection APS. The thickness and microstructure of the coating layers were evaluated, and x-ray diffraction analysis was performed on the coatings to detect material decomposition and the formation of undesired phases in the plasma. These results determined the envelope of plasma spray parameters in which coatings of LSCF can be manufactured, and the range of conditions in which composite cathode coatings could potentially be manufactured.

Synthesis, processing and characterization of the solid oxide half-cells cathode/electrolyte of strontium-doped lanthanum manganite/Yttria-stabilized zirconia

International Nuclear Information System (INIS)

Chiba, Rubens

2010-01-01

The ceramic films of strontium-doped lanthanum manganite (LSM) and strontium doped lanthanum manganite/Yttria-stabilized zirconia (LSM/YSZ) are used as cathodes of the high temperature solid oxide fuel cells (HTSOFC). These porous ceramic films had been deposited on the YSZ dense ceramic substrate, used as electrolyte, structural component of the module, thus conferring a configuration of half-cell called auto-support. The study of the half-cell it is basic, therefore in the interface cathode/electrolyte occurs the oxygen reduction reaction, consequently influencing in the performance of the HTSOFC. In this direction, the present work contributes for the processing of thin films, using the wet powder spraying technique, adopted for the conformation of the ceramic films for allowing the attainment of porous layers with thicknesses varied in the order of micrometers. The LSM powders were synthesized by the citrate technique and the LSM/YSZ powders synthesized by the solid mixture technique. In the stage of formation were prepared organic suspensions of LSM and LSM/YSZ fed by gravity in a manual aerograph. For the formation of the YSZ substrate was used a hydraulic uniaxial press. The attainment of solid oxide half-cells cathode/electrolyte was possible of crystalline structures hexagonal for phase LSM and cubic for phase YSZ. The half-cells micrographs show that the YSZ substrate is dense, enough to be used as solid electrolyte, and the LSM and LSM/YSZ films are presented porous with approximately 30 μm of thickness and good adherence between the cathodes and the electrolyte. The presence of composite cathode between the LSM cathode and YSZ substrate, presented an increase in the electrochemical performance in the oxygen reduction reaction. (author)

Highly durable anode supported solid oxide fuel cell with an infiltrated cathode

DEFF Research Database (Denmark)

Samson, Alfred Junio; Hjalmarsson, Per; Søgaard, Martin

2012-01-01

An anode supported solid oxide fuel cell with an La0.6Sr0.4Co1.05O3_δ (LSC) infiltrated-Ce0.9Gd0.1O1.95 (CGO) cathode that shows a stable performance has been developed. The cathode was prepared by screen printing a porous CGO backbone on top of a laminated and co-fired anode supported half cell...... was tested at 700 deg. C under a current density of 0.5 A cm-2 for 1500 h using air as oxidant and humidified hydrogen as fuel. The electrochemical performance of the cell was analyzed by impedance spectroscopy and current evoltage relationships. No measurable degradation in the cell voltage or increase...... in the resistance from the recorded impedance was observed during long term testing. The power density reached 0.79Wcm-2 at a cell voltage of 0.6 V at 750 deg. C. Post test analysis of the LSC infiltrated-CGO cathode by scanning electron microscopy revealed no significant micro-structural difference...

Cathode and electrolyte materials for solid oxide fuel cells and ion transport membranes

Science.gov (United States)

Jacobson, Allan J; Wang, Shuangyan; Kim, Gun Tae

2014-01-28

Novel cathode, electrolyte and oxygen separation materials are disclosed that operate at intermediate temperatures for use in solid oxide fuel cells and ion transport membranes based on oxides with perovskite related structures and an ordered arrangement of A site cations. The materials have significantly faster oxygen kinetics than in corresponding disordered perovskites.

Inkjet-Printed Porous Silver Thin Film as a Cathode for a Low-Temperature Solid Oxide Fuel Cell.

Science.gov (United States)

Yu, Chen-Chiang; Baek, Jong Dae; Su, Chun-Hao; Fan, Liangdong; Wei, Jun; Liao, Ying-Chih; Su, Pei-Chen

2016-04-27

In this work we report a porous silver thin film cathode that was fabricated by a simple inkjet printing process for low-temperature solid oxide fuel cell applications. The electrochemical performance of the inkjet-printed silver cathode was studied at 300-450 °C and was compared with that of silver cathodes that were fabricated by the typical sputtering method. Inkjet-printed silver cathodes showed lower electrochemical impedance due to their porous structure, which facilitated oxygen gaseous diffusion and oxygen surface adsorption-dissociation reactions. A typical sputtered nanoporous silver cathode became essentially dense after the operation and showed high impedance due to a lack of oxygen supply. The results of long-term fuel cell operation show that the cell with an inkjet-printed cathode had a more stable current output for more than 45 h at 400 °C. A porous silver cathode is required for high fuel cell performance, and the simple inkjet printing technique offers an alternative method of fabrication for such a desirable porous structure with the required thermal-morphological stability.

Phosphorus Enrichment as a New Composition in the Solid Electrolyte Interphase of High-Voltage Cathodes and Its Effects on Battery Cycling

Energy Technology Data Exchange (ETDEWEB)

Yan, Pengfei; Zheng, Jianming; Kuppan, Saravanan; Li, Qiuyan; Lv, Dongping; Xiao, Jie; Chen, Guoying; Zhang, Jiguang; Wang, Chong M.

2015-11-10

Immersion of a solid into liquid often leads to the modification of both the structure and chemistry of surface of the solid, which subsequently affects the chemical and physical properties of the system. For the case of the rechargeable lithium ion battery, such a surface modification is termed as solid electrolyte interphase (SEI) layer, which has been perceived to play critical role for the stable operation of the batteries. However, the structure and chemical composition of SEI layer and its spatial distribution and dependence on the battery operating condition remain unclear. By using aberration corrected scanning transmission electron microscopy coupled with ultra-high sensitive energy dispersive x-ray spectroscopy, we probed the structure and chemistry of SEI layer on several high voltage cathodes. We show that layer-structured cathodes, when cycled at a high cut off voltage, can form a P-rich SEI layer on their surface, which is a direct evidence of Li-salt (LiPF6) decomposition. Our systematical investigations indicate such cathode/Li-salt side reaction shows strong dependence on structure of the cathode materials, operating voltage and temperature, indicating the feasibility of SEI engineering. These findings provide us valuable insights into the complex interface between the high-voltage cathode and the electrolyte.

Modeling of thermal expansion coefficient of perovskite oxide for solid oxide fuel cell cathode

Science.gov (United States)

Heydari, F.; Maghsoudipour, A.; Alizadeh, M.; Khakpour, Z.; Javaheri, M.

2015-09-01

Artificial intelligence models have the capacity to eliminate the need for expensive experimental investigation in various areas of manufacturing processes, including the material science. This study investigates the applicability of adaptive neuro-fuzzy inference system (ANFIS) approach for modeling the performance parameters of thermal expansion coefficient (TEC) of perovskite oxide for solid oxide fuel cell cathode. Oxides (Ln = La, Nd, Sm and M = Fe, Ni, Mn) have been prepared and characterized to study the influence of the different cations on TEC. Experimental results have shown TEC decreases favorably with substitution of Nd3+ and Mn3+ ions in the lattice. Structural parameters of compounds have been determined by X-ray diffraction, and field emission scanning electron microscopy has been used for the morphological study. Comparison results indicated that the ANFIS technique could be employed successfully in modeling thermal expansion coefficient of perovskite oxide for solid oxide fuel cell cathode, and considerable savings in terms of cost and time could be obtained by using ANFIS technique.

Potentiometric titration of molybdenum (6) with a cathode-polarized solid electrode

International Nuclear Information System (INIS)

Boeva, L.V.; Kimstach, V.A.; Bagdasarov, K.N.

1980-01-01

The possibility has been studied of using solid electrodes for potentiometric precipitation titration of molybdenum (6). A cathode-polarized electrode, electrochemically covered with a molybdenum blue layer, can be used as indicator electrode. The best results were obtained during deposition of molybdenum blue on a tungsten electrode. The mechanism of electrode work during titration has been investigated. A procedure has been developed of titration of molybdenum (6) in acid solutions using hydroxylamine N-aryl derivatives as titrants

A high performance cathode for proton conducting solid oxide fuel cells

KAUST Repository

Wang, Zhiquan

2015-01-01

Intermediate temperature solid-oxide fuel cells (IT-SOFCs)), as one of the energy conversion devices, have attracted worldwide interest for their great fuel efficiency, low air pollution, much reduced cost and excellent longtime stability. In the intermediate temperature range (500-700°C), SOFCs based on proton conducting electrolytes (PSOFCs) display unique advantages over those based on oxygen ion conducting electrolytes. A key obstacle to the practical operation of past P-SOFCs is the poor stability of the traditionally used composite cathode materials in the steam-containing atmosphere and their low contribution to proton conduction. Here we report the identification of a new Ruddlesden-Popper-type oxide Sr3Fe2O7-δ that meets the requirements for much improved long-term stability and shows a superior single-cell performance. With a Sr3Fe2O7-δ-5 wt% BaZr0.3Ce0.5Y0.2O3-δ cathode, the P-SOFC exhibits high power densities (683 and 583 mW cm-2 at 700°C and 650°C, respectively) when operated with humidified hydrogen as the fuel and air as the cathode gas. More importantly, no decay in discharging was observed within a 100 hour test. © The Royal Society of Chemistry 2015.

Mechanistic modelling of a cathode-supported tubular solid oxide fuel cell

Science.gov (United States)

Suwanwarangkul, R.; Croiset, E.; Pritzker, M. D.; Fowler, M. W.; Douglas, P. L.; Entchev, E.

A two-dimensional mechanistic model of a tubular solid oxide fuel cell (SOFC) considering momentum, energy, mass and charge transport is developed. The model geometry of a single cell comprises an air-preheating tube, air channel, fuel channel, anode, cathode and electrolyte layers. The heat radiation between cell and air-preheating tube is also incorporated into the model. This allows the model to predict heat transfer between the cell and air-preheating tube accurately. The model is validated and shows good agreement with literature data. It is anticipated that this model can be used to help develop efficient fuel cell designs and set operating variables under practical conditions. The transport phenomena inside the cell, including gas flow behaviour, temperature, overpotential, current density and species concentration, are analysed and discussed in detail. Fuel and air velocities are found to vary along flow passages depending on the local temperature and species concentrations. This model demonstrates the importance of incorporating heat radiation into a tubular SOFC model. Furthermore, the model shows that the overall cell performance is limited by O 2 diffusion through the thick porous cathode and points to the development of new cathode materials and designs being important avenues to enhance cell performance.

On the nanostructuring and catalytic promotion of intermediate temperature solid oxide fuel cell (IT-SOFC) cathodes

Science.gov (United States)

Serra, José M.; Buchkremer, Hans-Peter

Solid oxide fuel cells (SOFCs) are highly efficient energy converters for both stationary and mobile purposes. However, their market introduction still demands the reduction of manufacture costs and one possible way to reach this goal is the decrease of the operating temperatures, which entails the improvement of the cathode electrocatalytic properties. An ideal cathode material may have mixed ionic and electronic conductivity as well as proper catalytic properties. Nanostructuring and catalytic promotion of mixed conducting perovskites (e.g. La 0.58Sr 0.4Fe 0.8Co 0.2O 3- δ) seem to be promising approaches to overcoming cathode polarization problems and are briefly illustrated here. The preparation of nanostructured cathodes with relatively high surface area and enough thermal stability enables to improve the oxygen exchange rate and therefore the overall SOFC performance. A similar effect was obtained by catalytic promoting the perovskite surface, allowing decoupling the catalytic and ionic-transport properties in the cathode design. Noble metal incorporation may improve the reversibility of the reduction cycles involved in the oxygen reduction. Under the cathode oxidizing conditions, Pd seems to be partially dissolved in the perovskite structure and as a result very well dispersed.

A niobium and tantalum co-doped perovskite cathode for solid oxide fuel cells operating below 500 °C

Science.gov (United States)

Li, Mengran; Zhao, Mingwen; Li, Feng; Zhou, Wei; Peterson, Vanessa K.; Xu, Xiaoyong; Shao, Zongping; Gentle, Ian; Zhu, Zhonghua

2017-01-01

The slow activity of cathode materials is one of the most significant barriers to realizing the operation of solid oxide fuel cells below 500 °C. Here we report a niobium and tantalum co-substituted perovskite SrCo0.8Nb0.1Ta0.1O3−δ as a cathode, which exhibits high electroactivity. This cathode has an area-specific polarization resistance as low as ∼0.16 and ∼0.68 Ω cm2 in a symmetrical cell and peak power densities of 1.2 and 0.7 W cm−2 in a Gd0.1Ce0.9O1.95-based anode-supported fuel cell at 500 and 450 °C, respectively. The high performance is attributed to an optimal balance of oxygen vacancies, ionic mobility and surface electron transfer as promoted by the synergistic effects of the niobium and tantalum. This work also points to an effective strategy in the design of cathodes for low-temperature solid oxide fuel cells. PMID:28045088

Real-time thermal imaging of solid oxide fuel cell cathode activity in working condition

DEFF Research Database (Denmark)

Montanini, Roberto; Quattrocchi, Antonino; Piccolo, Sebastiano

2016-01-01

Electrochemical methods such as voltammetry and electrochemical impedance spectroscopy are effective for quantifying solid oxide fuel cell (SOFC) operational performance, but not for identifying and monitoring the chemical processes that occur on the electrodes’ surface, which are thought...... to be strictly related to the SOFCs’ efficiency. Because of their high operating temperature, mechanical failure or cathode delamination is a common shortcoming of SOFCs that severely affects their reliability. Infrared thermography may provide a powerful tool for probing in situ SOFC electrode processes...... in detecting the onset of cell failure during normal operation and in monitoring cathode activity when the cell is fed with different types of fuels....

Mathematical modeling of current density distribution in composite cathode of solid oxide fuel cells. Paper no. IGEC-1-099

International Nuclear Information System (INIS)

Kenney, B.; Karan, K.

2005-01-01

Cathodes processes in a solid oxide fuel cell (SOFC) are thought to dominate the overall electrochemical losses. One strategy for minimizing the cathode electrochemical losses in a state-of-the-art SOFC that utilize lanthanum-strontium-manganate (LSM) electrocatalyst and yttria-stabilized-zirconia (YSZ) electrolyte is to utilize composite cathodes comprising a mixture of LSM and YSZ. Composite cathodes improve performance by extending the active reaction zone from electrolyte-electrode interface to throughout the electrode. In this study, a two-dimensional composite cathode model was developed to assess cathode performance in terms of current density distributions. The model results indicate that geometric and microstructural parameters strongly influence current density distribution. In addition electrode composition affects magnitude and distribution of current. An optimum composition for equal-sized LSM/YSZ is 40 vol% LSM and 60 vol% YSZ at 900 o C. (author)

Testing of a cathode fabricated by painting with a brush pen for anode-supported tubular solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Liu, Renzhu; Zhao, Chunhua; Li, Junliang; Wang, Shaorong; Wen, Zhaoyin; Wen, Tinglian [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

2010-01-15

We have studied the properties of a cathode fabricated by painting with a brush pen for use with anode-supported tubular solid oxide fuel cells (SOFCs). The porous cathode connects well with the electrolyte. A preliminary examination of a single tubular cell, consisting of a Ni-YSZ anode support tube, a Ni-ScSZ anode functional layer, a ScSZ electrolyte film, and a LSM-ScSZ cathode fabricated by painting with a brush pen, has been carried out, and an improved performance is obtained. The ohmic resistance of the cathode side clearly decreases, falling to a value only 37% of that of the comparable cathode made by dip-coating at 850 C. The single cell with the painted cathode generates a maximum power density of 405 mW cm{sup -2} at 850 C, when operating with humidified hydrogen. (author)

Stabilizing nanostructured solid oxide fuel cell cathode with atomic layer deposition.

Science.gov (United States)

Gong, Yunhui; Palacio, Diego; Song, Xueyan; Patel, Rajankumar L; Liang, Xinhua; Zhao, Xuan; Goodenough, John B; Huang, Kevin

2013-09-11

We demonstrate that the highly active but unstable nanostructured intermediate-temperature solid oxide fuel cell cathode, La0.6Sr0.4CoO3-δ (LSCo), can retain its high oxygen reduction reaction (ORR) activity with exceptional stability for 4000 h at 700 °C by overcoating its surfaces with a conformal layer of nanoscale ZrO2 films through atomic layer deposition (ALD). The benefits from the presence of the nanoscale ALD-ZrO2 overcoats are remarkable: a factor of 19 and 18 reduction in polarization area-specific resistance and degradation rate over the pristine sample, respectively. The unique multifunctionality of the ALD-derived nanoscaled ZrO2 overcoats, that is, possessing porosity for O2 access to LSCo, conducting both electrons and oxide-ions, confining thermal growth of LSCo nanoparticles, and suppressing surface Sr-segregation is deemed the key enabler for the observed stable and active nanostructured cathode.

Composite cathode materials development for intermediate temperature solid oxide fuel cell systems

Science.gov (United States)

Qin, Ya

Solid oxide fuel cell (SOFC) systems are of particular interest as electrochemical power systems that can operate on various hydrocarbon fuels with high fuel-to-electrical energy conversion efficiency. Within the SOFC stack, La0.8Sr 0.2Ga0.8Mg0.115Co0.085O3-delta (LSGMC) has been reported as an optimized composition of lanthanum gallate based electrolytes to achieve higher oxygen ionic conductivity at intermediate temperatures, i.e., 500-700°C. The electrocatalytic properties of interfaces between LSGMC electrolytes and various candidate intermediate-temperature SOFC cathodes have been investigated. Sm0.5Sr0.5CoO 3-delta (SSC), and La0.6Sr0.4Co0.2Fe 0.8O3-delta (LSCF), in both pure and composite forms with LSGMC, were investigated with regards to both oxygen reduction and evolution, A range of composite cathode compositions, having ratios of SSC (in wt.%) with LSGMC (wt.%) spanning the compositions 9:1, 8:2, 7:3, 6:4 and 5:5, were investigated to determine the optimal cathode-electrolyte interface performance at intermediate temperatures. All LSGMC electrolyte and cathode powders were synthesized using the glycine-nitrate process (GNP). Symmetrical electrochemical cells were investigated with three-electrode linear dc polarization and ac impedance spectroscopy to characterize the kinetics of the interfacial reactions in detail. Composite cathodes were found to perform better than the single phase cathodes due to significantly reduced polarization resistances. Among those composite SSC-LSGMC cathodes, the 7:3 composition has demonstrated the highest current density at the equivalent overpotential values, indicating that 7:3 is an optimal mixing ratio of the composite cathode materials to achieve the best performance. For the composite SC-LSGMC cathode/LSGMC interface, the cathodic overpotential under 1 A/cm2 current density was as low as 0.085 V at 700°C, 0.062V at 750°C and 0.051V at 800°C in air. Composite LSCF-LSGMC cathode/LSGMC interfaces were found to have

S-containing copolymer as cathode material in poly(ethylene oxide)-based all-solid-state Li-S batteries

Science.gov (United States)

Gracia, Ismael; Ben Youcef, Hicham; Judez, Xabier; Oteo, Uxue; Zhang, Heng; Li, Chunmei; Rodriguez-Martinez, Lide M.; Armand, Michel

2018-06-01

Inverse vulcanization copolymers (p(S-DVB)) from the radical polymerization of elemental sulfur and divinylbenzene (DVB) have been studied as cathode active materials in poly(ethylene oxide) (PEO)-based all-solid-state Li-S cells. The Li-S cell comprising the optimized p(S-DVB) cathode (80:20 w/w S/DVB ratio) and lithium bis(fluorosulfonyl)imide/PEO (LiFSI/PEO) electrolyte shows high specific capacity (ca. 800 mAh g-1) and high Coulombic efficiency for 50 cycles. Most importantly, polysulfide (PS) shuttle is highly mitigated due to the strong interactions of PS species with polymer backbone in p(S-DVB). This is demonstrated by the stable cycling of the p(S-DVB)-based cell using lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)/PEO electrolyte, where successful charging cannot be achieved even at the first cycle with plain elemental S-based cathode material due to the severe PS shuttle phenomenon. These results suggest that inverse vulcanization copolymers are promising alternatives to elemental sulfur for enhancing the electrochemical performance of PEO-based all-solid-state Li-S cells.

Prediction of inelastic behavior and creep-fatigue life of perforated plates

International Nuclear Information System (INIS)

Igari, Toshihide; Setoguchi, Katsuya; Nakano, Shohki; Nomura, Shinichi

1991-01-01

Prediction methods of macroscopic and local stress-strain behavior of perforated plates in plastic and creep regime which are proposed by the authors are applied to the inelastic analysis and creep-fatigue life prediction of perforated cylinder subjected to cyclic thermal stress. Stress-strain behavior of perforated cylinder is analyzed by modeling the perforated portion to cylinder with equivalent-solid-plate properties. Creep-fatigue lives at around a hole of perforated plates are predicted by using the local stress-strain behavior and are compared with experimentally observed lives. (author)

Beryllium electrodeposition on aluminium cathode from chloride melts

International Nuclear Information System (INIS)

Nichkov, I.F.; Novikov, E.A.; Serebryakov, G.A.; Kanashin, Yu.P.; Sardyko, G.N.

1980-01-01

Cathodic processes during beryllium deposition on liquid and solid aluminium cathodes are investigated. Mixture of sodium, potassium and beryllium chloride melts served as an lectrolyte. Beryllium ion discharge at the expense of alloy formation takes place at more positive potentials than on an indifferent cathode at low current densities ( in the case of liquid aluminium cathode). Metallographic analysis and measurements of microhardness have shown, that the cathodic product includes two phases: beryllium solid solution in aluminium and metallic beryllium. It is concluded, that aluminium-beryllium alloys with high cathodic yield by current can be obtained by the electrolytic method

Nanoporous silver cathode surface treated by atomic layer deposition of CeO_x for low-temperature solid oxide fuel cells

International Nuclear Information System (INIS)

Neoh, Ke Chean; Han, Gwon Deok; Kim, Manjin; Kim, Jun Woo; Choi, Hyung Jong; Park, Suk Won; Shim, Joon Hyung

2016-01-01

We evaluated the performance of solid oxide fuel cells (SOFCs) with a 50 nm thin silver (Ag) cathode surface treated with cerium oxide (CeO_x) by atomic layer deposition (ALD). The performances of bare and ALD-treated Ag cathodes were evaluated on gadolinia-doped ceria (GDC) electrolyte supporting cells with a platinum (Pt) anode over 300 °C–450 °C. Our work confirms that ALD CeO_x treatment enhances cathodic performance and thermal stability of the Ag cathode. The performance difference between cells using a Ag cathode optimally treated with an ALD CeO_x surface and a reference Pt cathode is about 50% at 450 °C in terms of fuel cell power output in our experiment. The bare Ag cathode completely agglomerated into islands during fuel cell operation at 450 °C, while the ALD CeO_x treatment effectively protects the porosity of the cathode. We also discuss the long-term stability of ALD CeO_x-treated Ag cathodes related to the microstructure of the layers. (paper)

Optimizing solid oxide fuel cell cathode processing route for intermediate temperature operation

DEFF Research Database (Denmark)

Ortiz-Vitoriano, N.; Bernuy-Lopez, Carlos; Ruiz de Larramendi, I.

2013-01-01

-priced raw material and cost-effective production techniques.In this work the perovskite-type La0.6Ca0.4Fe0.8Ni0.2O3 (LCFN) oxide has been used in order to optimize intermediate temperature SOFC cathode processing route. The advantages this material presents arise from the low temperature powder calcination......For Solid Oxide Fuel Cells (SOFCs) to become an economically attractive energy conversion technology suitable materials which allow operation at lower temperatures, while retaining cell performance, must be developed. At the same time, the cell components must be inexpensive - requiring both low...... (∼600°C) and electrode sintering (∼800°C) of LCFN electrodes, making them a cheaper alternative to conventional SOFC cathodes. An electrode polarization resistance as low as 0.10Ωcm2 at 800°C is reported, as determined by impedance spectroscopy studies of symmetrical cells sintered at a range...

Ab initio energetics of LaBO3(001) (B=Mn, Fe, Co, and Ni) for solid oxide fuel cell cathodes

DEFF Research Database (Denmark)

Lee, Yueh-Lin; Kleis, Jesper; Rossmeisl, Jan

2009-01-01

LaBO3 (B=Mn, Fe, Co, and Ni) perovskites form a family of materials of significant interest for cathodes of solid oxide fuel cells (SOFCs). In this paper ab initio methods are used to study both bulk and surface properties of relevance for SOFCs, including vacancy formation and oxygen binding...... reduction reaction on perovskite SOFC cathodes....

Improved performance of LaNi0.6Fe0.4O3 solid oxide fuel cell cathode by application of a thin interface cathode functional layer

DEFF Research Database (Denmark)

Molin, Sebastian; Jasinski, Piotr Z.

2017-01-01

In this work, novel functional layers were prepared by a low temperature spray pyrolysis method on the oxygen side of the solid oxide cells. Thin layers of Ce0.8Gd0.2O2 and LaNi0.6Fe0.4O3 are prepared between the electrolyte and the porous oxygen electrode. Additionally the influence of the sprayed...... ceria barrier layer on the zirconia based electrolyte with the new layers is evaluated. Impedance spectroscopy results show improvement in contact between the electrolyte and the porous cathode electrode. Additionally, electrochemical performance of the cathode is improved, as evidenced by a lowered...

Functionally Graded Cathodes for Solid Oxide Fuel Cells

International Nuclear Information System (INIS)

Lei Yang; Ze Liu; Shizhone Wang; Jaewung Lee; Meilin Liu

2008-01-01

The main objective of this DOE project is to demonstrate that the performance and long-term stability of the state-of-the-art LSCF cathode can be enhanced by a catalytically active coating (e.g., LSM or SSC). We have successfully developed a methodology for reliably evaluating the intrinsic surface catalytic properties of cathode materials. One of the key components of the test cell is a dense LSCF film, which will function as the current collector for the electrode material under evaluation to eliminate the effect of ionic and electronic transport. Since it is dense, the effect of geometry would be eliminated as well. From the dependence of the electrode polarization resistance on the thickness of a dense LSCF electrode and on partial pressure of oxygen, we have confirmed that the surface catalytic activity of LSCF limits the performances of LSCF-based cathodes. Further, we have demonstrated, using test cells of different configurations, that the performance of LSCF-based electrodes can be significantly enhanced by infiltration of a thin film of LSM or SSC. In addition, the stability of LSCF-based cathodes was also improved by infiltration of LSM or SSC. While the concept feasibility of the electrode architecture is demonstrated, many details are yet to be determined. For example, it is not clear how the surface morphology, composition, and thickness of the coatings change under operating conditions over time, how these changes influence the electrochemical behavior of the cathodes, and how to control the microscopic details of the coatings in order to optimize the performance. The selection of the catalytic materials as well as the detailed microstructures of the porous LSCF and the catalyst layer may critically impact the performance of the proposed cathodes. Further, other fundamental questions still remain; it is not clear why the degradation rates of LSCF cathodes are relatively high, why a LSM coating improves the stability of LSCF cathodes, which catalysts

An Aurivillius Oxide Based Cathode with Excellent CO2 Tolerance for Intermediate-Temperature Solid Oxide Fuel Cells.

Science.gov (United States)

Zhu, Yinlong; Zhou, Wei; Chen, Yubo; Shao, Zongping

2016-07-25

The Aurivillius oxide Bi2 Sr2 Nb2 MnO12-δ (BSNM) was used as a cobalt-free cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). To the best of our knowledge, the BSNM oxide is the only alkaline-earth-containing cathode material with complete CO2 tolerance that has been reported thus far. BSNM not only shows favorable activity in the oxygen reduction reaction (ORR) at intermediate temperatures but also exhibits a low thermal expansion coefficient, excellent structural stability, and good chemical compatibility with the electrolyte. These features highlight the potential of the new BSNM material as a highly promising cathode material for IT-SOFCs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Theory of electroreduction of solid oxide electrolytes. Kinetics and mechanism of the galvanostatic process with blocking cathodes

International Nuclear Information System (INIS)

Chebotin, V.N.; Brainin, M.I.; Lukach, Yu. S.; Pakhnutov, I.A.; Solov'eva, L.M.

1986-01-01

This paper discusses dc flow through cells with MO 2 + MeOΓ solid electrolyte (M = Zr, Hf, Ce, or Th; Me = Ca, Sr, Sc, Y, or lanthanides), a blocking cathode, and a reversible anode which leads to departures of the electrolytes from stoichiometry in the direction of oxygen deficiency. A nonlinear differential equation of the diffusion type describes the degree of this departure and the n-type electronic conductivity which is proportional to it, as functions of the coordinate and time. The electrolyte's electronic conductivity increases with time near the cathode, and approaches a limiting value that is proportional to the current being passed. The electronic conductivity falls off exponentially with increasing distance from the cathode; this changes to a linear fall as a function of time

Chromium poisoning in (La,Sr)MnO3 cathode: Three-dimensional simulation of a solid oxide fuel cell

OpenAIRE

Miyoshi, Kota; Iwai, Hiroshi; Kishimoto, Masashi; Saito, Motohiro; Yoshida, Hideo

2016-01-01

A three-dimensional numerical model of a single solid oxide fuel cell (SOFC) considering chromium poisoning on the cathode side has been developed to investigate the evolution of the SOFC performance over long-term operation. The degradation model applied in the simulation describes the loss of the cathode electrochemical activity as a decrease in the active triple-phase boundary (TPB) length. The calculations are conducted for two types of cell: lanthanum strontium manganite (LSM)/yttria-sta...

Copper-substituted perovskite compositions for solid oxide fuel cell cathodes and oxygen reduction electrodes in other electrochemical devices

Science.gov (United States)

Rieke, Peter C [Pasco, WA; Coffey, Gregory W [Richland, WA; Pederson, Larry R [Kennewick, WA; Marina, Olga A [Richland, WA; Hardy, John S [Richland, WA; Singh, Prabhaker [Richland, WA; Thomsen, Edwin C [Richland, WA

2010-07-20

The present invention provides novel compositions that find advantageous use in making electrodes for electrochemical cells. Also provided are electrochemical devices that include active oxygen reduction electrodes, such as solid oxide fuel cells, sensors, pumps and the like. The compositions comprises a copper-substituted ferrite perovskite material. The invention also provides novel methods for making and using the electrode compositions and solid oxide fuel cells and solid oxide fuel cell assemblies having cathodes comprising the compositions.

Methods and apparatuses for making cathodes for high-temperature, rechargeable batteries

Science.gov (United States)

Meinhardt, Kerry D; Sprenkle, Vincent L; Coffey, Gregory W

2014-05-20

The approaches for fabricating cathodes can be adapted to improve control over cathode composition and to better accommodate batteries of any shape and their assembly. For example, a first solid having an alkali metal halide, a second solid having a transition metal, and a third solid having an alkali metal aluminum halide are combined into a mixture. The mixture can be heated in a vacuum to a temperature that is greater than or equal to the melting point of the third solid. When the third solid is substantially molten liquid, the mixture is compressed into a desired cathode shape and then cooled to solidify the mixture in the desired cathode shape.

Separation of actinides from irradiated An–Zr based fuel by electrorefining on solid aluminium cathodes in molten LiCl–KCl

Energy Technology Data Exchange (ETDEWEB)

Souček, P., E-mail: Pavel.Soucek@ec.europa.eu [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe (Germany); Murakami, T. [Central Research Institute of Electric Power Industry (CRIEPI), Komae-shi, Tokyo 201-8511 (Japan); Claux, B.; Meier, R.; Malmbeck, R. [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe (Germany); Tsukada, T. [Central Research Institute of Electric Power Industry (CRIEPI), Komae-shi, Tokyo 201-8511 (Japan); Glatz, J.-P. [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe (Germany)

2015-04-15

Highlights: • Electrorefining process in molten LiCl-KCl using solid Al electrodes was demonstrated. • High separation factors of actinides over lanthanides were achieved. • Efficient recovery of actinides from irradiated nuclear fuel was achieved. • Uniform, dense and well adhered deposits were obtained and characterised. • Kinetic parameters of actinide–aluminium alloy formation were evaluated. - Abstract: An electrorefining process for metallic spent nuclear fuel treatment is being investigated in ITU. Solid aluminium cathodes are used for homogeneous recovery of all actinides within the process carried out in molten LiCl–KCl eutectic salt at a temperature of 500 °C. As the selectivity, efficiency and performance of solid Al has been already shown using un-irradiated An–Zr alloy based test fuels, the present work was focused on laboratory-scale demonstration of the process using irradiated METAPHIX-1 fuel composed of U{sub 67}–Pu{sub 19}–Zr{sub 10}–MA{sub 2}–RE{sub 2} (wt.%, MA = Np, Am, Cm, RE = Nd, Ce, Gd, Y). Different electrorefining techniques, conditions and cathode geometries were used during the experiment yielding evaluation of separation factors, kinetic parameters of actinide–aluminium alloy formation, process efficiency and macro-structure characterisation of the deposits. The results confirmed an excellent separation and very high efficiency of the electrorefining process using solid Al cathodes.

Effect of substrate and cathode parameters on the properties of suspension plasma sprayed solid oxide fuel cell electrolytes

Energy Technology Data Exchange (ETDEWEB)

Waldbillig, D.; Tang, Z.; Burgess, A. [British Columbia Univ., Vancouver, BC (Canada); Kesler, O. [Toronto Univ., ON (Canada)

2008-07-01

An axial injection suspension plasma spray system has been used to produce layers of fully stabilized yttriastabilized zirconia (YSZ) that could be used as solid oxide fuel cell (SOFC) electrolytes. Suspension plasma spraying is a promising technique for the rapid production of coatings with fine microstructures and controlled porosity without requiring a post-deposition heat treatment. This new manufacturing technique to produce SOFC active layers requires the build up of a number of different plasma sprayed SOFC functional layers (cathode, electrolyte and anode) sequentially on top of each other. To understand the influence of the substrate and previouslydeposited coating layers on subsequent coating layer properties, YSZ layers were deposited on top of plasma sprayed composite lanthanum strontium manganite (LSM)/YSZ cathode layers that were first deposited on porous ferritic stainless steel substrates. Three layer half cells consisting of the porous steel substrate, composite cathode, and suspension plasma sprayed electrolyte layer were then characterized. A systematic study was performed in order to investigate the effect of parameters such as substrate and cathode layer roughness, substrate surface pore size, and cathode microstructure and thickness on electrolyte deposition efficiency, cathode and electrolyte permeability, and layer microstructure. (orig.)

Equivalent Young's Modulus of Perforated Shell with Square Penetration Pattern

Energy Technology Data Exchange (ETDEWEB)

Jhung, Myung Jo; Ryu, Yong Ho [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2011-05-15

The analysis of a plate or shell perforated with a large number of holes, by finite element method for instance, was a very costly and time-consuming technique which solves only one particular problem. But it is possible to model the perforated plate or shell and to analyze it and it is no more time-consuming theses days due to the rapid development of the computer and software. However, if a perforated plate or shell is submerged in fluid it is almost impossible to model and analyze it as is and the fluid at the same time, which is needed to investigate the effect of the fluid structure interaction. The simplest way to avoid time consuming and costly analysis of perforated plate or shell submerged in fluid is to replace the perforated plate or shell by an equivalent solid one considering weakening effect of holes. Many authors have proposed experimental or theoretical method to solve this problem for the plate. Slot and O'Donnell determined the effective elastic constants for the thick perforated plates by equating strains in the equivalent solid material to the average strains in the perforated material. O'Donnell also presented those of thin perforated plates. These results are implemented in Article A-8000 of Appendix A to the ASME code Section III, which contains a method of analysis for flat perforated plates when subjected to directly applied loads or loadings resulting from structural interaction with adjacent members. Unfortunately the effective elastic constants for the perforated shell are not found in any references. Therefore in this study the modal characteristics of the perforated shell are investigated and the equivalent material properties of perforated shell are suggested by performing several finite element analyses with respect to the ligament efficiencies

Cathode material for lithium batteries

Science.gov (United States)

Park, Sang-Ho; Amine, Khalil

2013-07-23

A method of manufacture an article of a cathode (positive electrode) material for lithium batteries. The cathode material is a lithium molybdenum composite transition metal oxide material and is prepared by mixing in a solid state an intermediate molybdenum composite transition metal oxide and a lithium source. The mixture is thermally treated to obtain the lithium molybdenum composite transition metal oxide cathode material.

Preparation of cathode materials for solid oxide solid fuel (SOFC) using gelatin

International Nuclear Information System (INIS)

Silva, R.M.; Aquino, F. de M.; Macedo, D.A. de; Sa, A.M.; Galvao, G.O.

2016-01-01

Fuel cells are electrochemical devices that convert chemical energy into electrical energy. These devices are basically divided into interconnectors, electrolyte, anode, and cathode. Recently, studies of improvements in microstructural and morphological properties of calcium cobaltate (Ca_3Co_4O_9, C349) has been made regarding its potential use as SOFC cathode for intermediate temperature. Gelatin has proven to be effective as a polymerizing agent in the synthesis of nanocrystalline materials. This work reports the synthesis and characterization of the C349 cathode using commercial gelatin. The structural properties of the material were determined by X-ray diffraction (XRD). Morphological characterization was performed by scanning electron microscopy (SEM). The results showed the formation of the crystalline phase at 900 °C, indicating the effectiveness of the gelatin in the preparation of cathodes for SOFC. (author)

Mechanism of chromium poisoning the conventional cathode material for solid oxide fuel cells

Science.gov (United States)

Zhang, Xiaoqiang; Yu, Guangsen; Zeng, Shumao; Parbey, Joseph; Xiao, Shuhao; Li, Baihai; Li, Tingshuai; Andersson, Martin

2018-03-01

Chromium poisoning the La0.875Sr0.125MnO3 (LSM) cathode for solid oxide fuel cells is a critical issue that can strongly affect the stability. In this study, we evaluate the temperature distribution in a SOFC based on a 3D model and then combine conductivity test and material computation to reveal the effects of chromium in SUS430 stainless steels on LSM conductivities. The starch concentration in LSM pellets and the applied pressure on the contact with interconnect materials show close relationships with the chromium poisoning behavior. The density functional theory (DFT) computing results indicate that chromium atoms preferably adsorb on the MnO2-terminated and La (Sr)-O-terminated (001) surfaces. The resulting conclusions are expected to deeply understand mechanism of chromium deactivating conventional cathodes at some typical operational conditions, and offer crucial information to optimize the structure to avoid the poisoning effect.

SmBaCoCuO5+x as cathode material based on GDC electrolyte for intermediate-temperature solid oxide fuel cells

International Nuclear Information System (INIS)

Lue Shiquan; Long, Guohui; Ji Yuan; Meng Xiangwei; Zhao Hongyuan; Sun Cuicui

2011-01-01

Research highlights: → We synthesize a new kind of layered perovskite SmBaCoCuO 5+x (SBCCO) as a cathode material of a solid oxide fuel cell. → There are some reports on the performance of cathodes in proton-conducting SOFCs based on BaCe 0.8 Sm 0.2 O 3-δ electrolyte. → However, to the best of our knowledge, the performance of SBCCO cathodes in oxygen-ion conducting SOFCs has not been reported to date. → In this work, the ceramic powder SBCCO is examined as a cathode for IT-SOFCs based on Ce 0.9 Gd 0.1 O 1.95 (GDC) electrolyte. - Abstract: The performance of SmBaCoCuO 5+x (SBCCO) cathode has been investigated for their potential utilization in intermediate-temperature solid oxide fuel cells (IT-SOFCs). The powder X-ray diffraction (XRD), thermal expansion and electrochemical performance on Ce 0.9 Gd 0.1 O 1.95 (GDC) electrolyte are evaluated. XRD results show that there is no chemical reaction between SBCCO cathode and GDC electrolyte when the temperature is below 950 o C. The thermal expansion coefficient (TEC) value of SBCCO is 15.53 x 10 -6 K -1 , which is ∼23% lower than the TEC of the SmBaCo 2 O 5+x (SBCO) sample. The electrochemical impedance spectra reveals that SBCCO symmetrical half-cells by sintering at 950 deg. C has the best electrochemical performance and the area specific resistance (ASR) of SBCCO cathode is as low as 0.086 Ω cm 2 at 800 o C. An electrolyte-supported fuel cell generates good performance with the maximum power density of 517 mW cm -2 at 800 deg. C in H 2 . Preliminary results indicate that SBCCO is promising as a cathode for IT-SOFCs.

Tailored Core Shell Cathode Powders for Solid Oxide Fuel Cells

Energy Technology Data Exchange (ETDEWEB)

Swartz, Scott [NexTech Materials, Ltd.,Lewis Center, OH (United States)

2015-03-23

In this Phase I SBIR project, a “core-shell” composite cathode approach was evaluated for improving SOFC performance and reducing degradation of lanthanum strontium cobalt ferrite (LSCF) cathode materials, following previous successful demonstrations of infiltration approaches for achieving the same goals. The intent was to establish core-shell cathode powders that enabled high performance to be obtained with “drop-in” process capability for SOFC manufacturing (i.e., rather than adding an infiltration step to the SOFC manufacturing process). Milling, precipitation and hetero-coagulation methods were evaluated for making core-shell composite cathode powders comprised of coarse LSCF “core” particles and nanoscale “shell” particles of lanthanum strontium manganite (LSM) or praseodymium strontium manganite (PSM). Precipitation and hetero-coagulation methods were successful for obtaining the targeted core-shell morphology, although perfect coverage of the LSCF core particles by the LSM and PSM particles was not obtained. Electrochemical characterization of core-shell cathode powders and conventional (baseline) cathode powders was performed via electrochemical impedance spectroscopy (EIS) half-cell measurements and single-cell SOFC testing. Reliable EIS testing methods were established, which enabled comparative area-specific resistance measurements to be obtained. A single-cell SOFC testing approach also was established that enabled cathode resistance to be separated from overall cell resistance, and for cathode degradation to be separated from overall cell degradation. The results of these EIS and SOFC tests conclusively determined that the core-shell cathode powders resulted in significant lowering of performance, compared to the baseline cathodes. Based on the results of this project, it was concluded that the core-shell cathode approach did not warrant further investigation.

Mechanistic Enhancement of SOFC Cathode Durability

Energy Technology Data Exchange (ETDEWEB)

Wachsman, Eric [Univ. of Maryland, College Park, MD (United States)

2016-02-01

Durability of solid oxide fuel cells (SOFC) under “real world” conditions is an issue for commercial deployment. In particular cathode exposure to moisture, CO2, Cr vapor (from interconnects and BOP), and particulates results in long-term performance degradation issues. Here, we have conducted a multi-faceted fundamental investigation of the effect of these contaminants on cathode performance degradation mechanisms in order to establish cathode composition/structures and operational conditions to enhance cathode durability.

Performance and Structural Evolution of Nano-Scale Infiltrated Solid Oxide Fuel Cell Cathodes

Science.gov (United States)

Call, Ann Virginia

Nano-structured mixed ionic and electronic conducting (MIEC) materials have garnered intense interest in electrode development for solid oxide fuel cells due to their high surface areas which allow for effective catalytic activity and low polarization resistances. In particular, composite solid oxide fuel cell (SOFC) cathodes consisting of ionic conducting scaffolds infiltrated with MIEC nanoparticles have exhibited some of the lowest reported polarization resistances. In order for cells utilizing nanostructured moRPhologies to be viable for commercial implementation, more information on their initial performance and long term stability is necessary. In this study, symmetric cell cathodes were prepared via wet infiltration of Sr0.5Sm 0.5CoO3 (SSC) nano-particles via a nitrate process into porous Ce0.9Gd0.1O1.95 (GDC) scaffolds to be used as a model system to investigate performance and structural evolution. Detailed analysis of the cells and cathodes was carried out using electrochemical impedance spectroscopy (EIS). Initial polarization resistances (RP) as low as 0.11 O cm2 at 600ºC were obtained for these SSC-GDC cathodes, making them an ideal candidate for studying high performance nano-structured electrodes. The present results show that the infiltrated cathode microstructure has a direct impact on the initial performance of the cell. Small initial particle sizes and high infiltration loadings (up to 30 vol% SSC) improved initial RP. A simple microstructure-based electrochemical model successfully explained these trends in RP. Further understanding of electrode performance was gleaned from fitting EIS data gathered under varying temperatures and oxygen partial pressures to equivalent circuit models. Both RQ and Gerischer impedance elements provided good fits to the main response in the EIS data, which was associated with the combination of oxygen surface exchange and oxygen diffusion in the electrode. A gas diffusion response was also observed at relatively

LaNi1-xCoxO3-δ (x=0.4 to 0.7) cathodes for solid oxide fuel cells by infiltration

DEFF Research Database (Denmark)

Chrzan, Aleksander; Ovtar, Simona; Chen, Ming

2015-01-01

Performance of LaNi1-xCoxO3-δ (LNC) (x=0.4 to 0.7) as a cathode in solid oxide fuel cell (SOFC) is evaluated. Symmetrical cathode/electrolyte/cathode cells for electrochemical testing are prepared by infiltration of yttria stabilized zirconia (YSZ) backbone with LNC solutions. It is showed...... that the cathode infiltrated with LaNi0.5Co0.5O3-δ (LNC155) has the lowest polarization resistance and activation energy, 197 mΩ cm2 at 600 °C and 0.91 eV, respectively. Therefore it is the most promising material of the LNC group for electrochemical applications. X-ray diffraction analysis revealed that none...

Study on modal characteristics of perforated shell using effective Young's modulus

International Nuclear Information System (INIS)

Jhung, Myung Jo; Yu, Seon Oh

2011-01-01

Research highlights: → The effective Young's modulus of perforated shell is proposed for modal analysis. → The penetration pattern is almost negligible for effective elastic constants. → The frequency of perforated shell decreases significantly due to the hole effect. - Abstract: For the perforated cylindrical shell submerged in fluid, it is almost impossible to develop a finite element model due to the necessity of the fine meshing of the shell and the fluid at the same time. This necessitates the use of solid shell with effective material properties. Unfortunately the effective elastic constants are not found in any references even though the ASME code is suggesting those for perforated plate. Therefore in this study the effective material properties of perforated shell are suggested by performing several finite element analyses with respect to the ligament efficiencies.

Methods for using novel cathode and electrolyte materials for solid oxide fuel cells and ion transport membranes

Science.gov (United States)

Jacobson, Allan J.; Wang, Shuangyan; Kim, Gun Tae

2016-01-12

Methods using novel cathode, electrolyte and oxygen separation materials operating at intermediate temperatures for use in solid oxide fuel cells and ion transport membranes include oxides with perovskite related structures and an ordered arrangement of A site cations. The materials have significantly faster oxygen kinetics than in corresponding disordered perovskites.

Composite cathode La0.15Bi0.85O1.5-Ag for intermediate-temperature solid oxide fuel cells

International Nuclear Information System (INIS)

Gao Zhan; Mao Zongqiang; Huang Jianbing; Gao Ruifeng; Wang Cheng; Liu Zhixiang

2008-01-01

Composites consisting of silver and lanthanum stabilized bismuth oxide (La 0.15 Bi 0.85 O 1.5 ) were investigated as cathodes for intermediate-temperature solid oxide fuel cells with doped ceria as electrolyte. No stable phases were formed via reaction between La 0.15 Bi 0.85 O 1.5 and Ag. The microstructure of the interfaces between composite cathodes and Ce 0.8 Sm 0.2 O 1.5 electrolytes was studied by scanning electron microscopy after sintering at various temperatures. Impedance spectroscopy measurements revealed that the performance of cathode fired at 700 deg. C was the best. When the optimum fraction of Ag was 50 vol.%, polarization resistance values for the LSB-Ag50 cathode were as low as 0.14 Ω cm 2 at 700 deg. C and 0.18 Ω cm 2 at 650 deg. C. The steady-state polarization investigations on LSB and LSB-Ag50 cathodes were performed using typical three-electrode test cells in air. The results showed that the LSB-Ag50 composite cathode exhibited a lower overpotential and higher exchange current density than LSB, which indicated the electrochemical performance of LSB-Ag50 for the oxygen reduction reaction was superior to the LSB

Typhoid Intestinal Perforation: 24 Perforations in One Patient

African Journals Online (AJOL)

Intestinal perforation is a common cause of peritonitis necessitating emergency surgical intervention. Perforation ... Mortality rates of typhoid intestinal perforation (TIP) cases are ... may be obscured clinical features with resultant delays in.

Comparison Between Conventional Design and Cathode Gas Recirculation Design of a Direct-Syngas Solid Oxide Fuel Cell–Gas Turbine Hybrid Systems Part I: Design Performance

Directory of Open Access Journals (Sweden)

Vahid Azami

2017-06-01

Keywords: Solid oxide fuel cell, Gas turbine, Cathode gas recirculation, Exergy. Article History: Received Feb 23rd 2017; Received in revised form May 26th 2017; Accepted June 1st 2017; Available online How to Cite This Article: Azami, V, and Yari, M. (2017 Comparison between conventional design and cathode gas recirculation design of a direct-syngas solid oxide fuel cell–gas turbine hybrid systems part I: Design performance. International Journal of Renewable Energy Develeopment, 6(2, 127-136. https://doi.org/10.14710/ijred.6.2.127-136

Lanthanum manganate based cathodes for solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Juhl Joergensen, M.

2001-07-01

Composite cathodes for solid oxide fuel cells were investigated using electrochemical impedance spectroscopy and scanning electron microscopy. The aim was to study the oxygen reduction process in the electrode in order to minimise the voltage drop in the cathode. The electrodes contained a composite layer made from lanthanum strontium manganate (LSM) and yttria stabilised zirconia (YSZ) and a layer of pure LSM aimed for current collection. The performance of the composite electrodes was sensitive to microstructure and thickness. Further, the interface between the composite and the current collecting layer proved to affect the performance. In a durability study severe deg-radation of the composite electrodes was found when passing current through the electrode for 2000 hours at 1000 deg. C. This was ascribed to pore formation along the composite interfaces and densification of the composite and current collector microstructure. An evaluation of the measurement approach indicated that impedance spectroscopy is a very sensitive method. This affects the reproducibility, as small undesirable variations in for instance the microstructure from electrode to electrode may change the impedance. At least five processes were found to affect the impedance of LSM/YSZ composite electrodes. Two high frequency processes were ascribed to transport of oxide ions/oxygen intermediates across LSM/YSZ interfaces and through YSZ in the composite. Several competitive elementary reaction steps, which appear as one medium frequency process in the impedance spectra, were observed. A low frequency arc related to gas diffusion limitation in a stagnant gas layer above the composite structure was detected. Finally, an inductive process, assumed to be connected to an activation process involving segregates at the triple phase boundary between electrode, electrolyte and gas phase, was found. (au)

The effect of oxygen transfer mechanism on the cathode performance based on proton-conducting solid oxide fuel cells

KAUST Repository

Hou, Jie

2015-01-01

Two types of proton-blocking composites, La2NiO4+δ-LaNi0.6Fe0.4O3-δ (LNO-LNF) and Sm0.2Ce0.8O2-δ-LaNi0.6Fe0.4O3-δ (SDC-LNF), were evaluated as cathode materials for proton-conducting solid oxide fuel cells (H-SOFCs) based on the BaZr0.1Ce0.7Y0.2O3-δ (BZCY) electrolyte, in order to compare and investigate the influence of two different oxygen transfer mechanism on the performance of the cathode for H-SOFCs. The X-ray diffraction (XRD) results showed that the chemical compatibility of the components in both compounds was excellent up to 1000°C. Electrochemical studies revealed that LNO-LNF showed lower area specific polarization resistances in symmetrical cells and better electrochemical performance in single cell tests. The single cell with LNO-LNF cathode generated remarkable higher maximum power densities (MPDs) and lower interfacial polarization resistances (Rp) than that with SDC-LNF cathode. Correspondingly, the MPDs of the single cell with the LNO-LNF cathode were 490, 364, 266, 180 mW cm-2 and the Rp were 0.103, 0.279, 0.587, 1.367 Ω cm2 at 700, 650, 600 and 550°C, respectively. Moreover, after the single cell with LNO-LNF cathode optimized with an anode functional layer (AFL) between the anode and electrolyte, the power outputs reached 708 mW cm-2 at 700°C. These results demonstrate that the LNO-LNF composite cathode with the interstitial oxygen transfer mechanism is a more preferable alternative for H-SOFCs than SDC-LNF composite cathode with the oxygen vacancy transfer mechanism.

Nanotubes of rare earth cobalt oxides for cathodes of intermediate-temperature solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Sacanell, Joaquin [Departamento de Fisica, Centro Atomico Constituyentes, CNEA, Av. Gral. Paz 1499, 1650 San Martin, Buenos Aires (Argentina); CINSO (Centro de Investigaciones en Solidos), CITEFA-CONICET, J.B. de La Salle 4397, 1603 Villa Martelli, Buenos Aires (Argentina); Leyva, A. Gabriela [Departamento de Fisica, Centro Atomico Constituyentes, CNEA, Av. Gral. Paz 1499, 1650 San Martin, Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, UNSAM. Av. Gral. Paz 1499, 1650 San Martin, Buenos Aires (Argentina); Bellino, Martin G.; Lamas, Diego G. [CINSO (Centro de Investigaciones en Solidos), CITEFA-CONICET, J.B. de La Salle 4397, 1603 Villa Martelli, Buenos Aires (Argentina)

2010-04-02

In this work we studied the electrochemical properties of cathodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs) prepared with nanotubes of La{sub 0.6}Sr{sub 0.4}CoO{sub 3} (LSCO). Their nanostructures consist of agglomerated nanoparticles in tubular structures of sub-micrometric diameter. The resulting cathodes are highly porous both at the micro- and the nanoscale. This fact increases significantly the access to active sites for the oxygen reduction. We investigated the influence of the diameter of the precursor nanotubes on the polarization resistance of the LSCO cathodes on CeO{sub 2}-10 mol.% Sm{sub 2}O{sub 3} (SDC) electrolytes under air atmosphere, evaluated in symmetrical [LSCO/SDC/LSCO] cells. Our results indicate an optimized performance when the diameter of precursor nanotubes is sufficiently small to become dense nanorods after cathode sintering. We present a phenomenological model that successfully explains the behavior observed and considers that a small starting diameter acts as a barrier that prevents grains growth. This is directly related with the lack of contact points between nanotubes in the precursor, which are the only path for the growth of ceramic grains. We also observed that a conventional sintering process (of 1 h at 1000 C with heating and cooling rates of 10 C min{sup -1}) has to be preferred against a fast firing one (1 or 2 min at 1100 C with heating and cooling rates of 100 C min{sup -1}) in order to reach a higher performance. However, a good adhesion of the cathode can be achieved with both methods. Our results suggest that oxygen vacancy diffusion is enhanced while decreasing LSCO particle size. This indicates that the high performance of our nanostructured cathodes is not only related with the increase of the number of active sites for oxygen reduction but also to the fact that the nanotubes are formed by nanoparticles. (author)

Lithiated Nafion as polymer electrolyte for solid-state lithium sulfur batteries using carbon-sulfur composite cathode

Science.gov (United States)

Gao, Jing; Sun, Chunshui; Xu, Lei; Chen, Jian; Wang, Chong; Guo, Decai; Chen, Hao

2018-04-01

Due to flexible property and light weight, the lithiated Nafion membrane swollen with PC (PC-Li-Nafion) has been employed as both solid-state electrolyte and separator to fabricate solid-state Li-S cells. The electrochemical measurements of PC-Li-Nafion membrane show that its Li-ion transference number is 0.928, ionic conductivity of 2.1 × 10-4 S cm-1 can be achieved at 70 °C and its electrochemical window is 0 ∼ +4.1 V vs. Li+/Li. It is observed that the Li dendrites are suppressed by using PC-Li-Nafion membrane due to its single-ion conducting property. The amounts of Li-Nafion resin binder and conductive carbon in the cathode are optimized as 40% and 10% respectively to make a balance of ionic and electronic conductivities. A thin-layer Li-Nafion resin with a thickness of around 2 μm is fabricated between the cathode and PC-Li-Nafion membrane to improve the interfacial contact and further enhance the specific capacity of the cell. When measured at 70 °C, the Li-S cell delivers a reversible specific capacity of 1072.8 mAh g-1 (S) at 0.05 C and 895 mAh g-1 (S) at 1 C. The capacity retention at 1 C is 89% after 100 cycles. These results suggest that high-performance solid-state Li-S cells can be fabricated with the Li-Nafion polymer electrolyte.

Co-free, iron perovskites as cathode materials for intermediate-temperature solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Hou, Shu-en [Engineering Research Center of Nano-Geo Materials of Ministry of Education, China University of Geosciences, Wuhan, 430074 (China); Texas Materials Institute, ETC 9.102, The University of Texas at Austin, Austin, TX 78712 (United States); Alonso, Jose Antonio [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain); Texas Materials Institute, ETC 9.102, The University of Texas at Austin, Austin, TX 78712 (United States); Goodenough, John B. [Texas Materials Institute, ETC 9.102, The University of Texas at Austin, Austin, TX 78712 (United States)

2010-01-01

We have developed a Co-free solid oxide fuel cell (SOFC) based upon Fe mixed oxides that gives an extraordinary performance in test-cells with H{sub 2} as fuel. As cathode material, the perovskite Sr{sub 0.9}K{sub 0.1}FeO{sub 3-{delta}} (SKFO) has been selected since it has an excellent ionic and electronic conductivity and long-term stability under oxidizing conditions; the characterization of this material included X-ray diffraction (XRD), thermal analysis, scanning microscopy and conductivity measurements. The electrodes were supported on a 300-{mu}m thick pellet of the electrolyte La{sub 0.8}Sr{sub 0.2}Ga{sub 0.83}Mg{sub 0.17}O{sub 3-{delta}} (LSGM) with Sr{sub 2}MgMoO{sub 6} as the anode and SKFO as the cathode. The test cells gave a maximum power density of 680 mW cm{sup -2} at 800 C and 850 mW cm{sup -2} at 850 C, with pure H{sub 2} as fuel. The electronic conductivity shows a change of regime at T {approx} 350 C that could correspond to the phase transition from tetragonal to cubic symmetry. The high-temperature regime is characterized by a metallic-like behavior. At 800 C the crystal structure contains 0.20(1) oxygen vacancies per formula unit randomly distributed over the oxygen sites (if a cubic symmetry is assumed). The presence of disordered vacancies could account, by itself, for the oxide-ion conductivity that is required for the mass transport across the cathode. The result is a competitive cathode material containing no cobalt that meets the target for the intermediate-temperature SOFC. (author)

On the Properties and Long-Term Stability of Infiltrated Lanthanum Cobalt Nickelates (LCN) in Solid Oxide Fuel Cell Cathodes

DEFF Research Database (Denmark)

Kiebach, Wolff-Ragnar; Zielke, Philipp; Veltzé, Sune

2017-01-01

Infiltration as a fabrication method for solid oxide fuel cells (SOFC) electrodes is offering significant improvements in cell performance at reduced materials and fabrication costs, especially when combined with co-sintering. However, important questions regarding the long-term performance...... and microstructural stability remain unanswered. Here, we present the results of a three-year project, where large footprint anode-supported SOFCs with a co-sintered cathode backbone and infiltrated La0.95Co0.4Ni0.6O3 (LCN) cathodes were developed and thoroughly characterized. The initial long-term performance...... in the electrode properties using SEM, BET area, and in-plane conductivity measurements. Finally, the mechanical properties of co-sintered cathode backbone cells were determined in four-point bending tests carried out both at room temperature and at 800°C in air. Based on these results, degradation mechanisms were...

Nanostructured LnBaCo2O6− (Ln = Sm, Gd with layered structure for intermediate temperature solid oxide fuel cell cathodes

Directory of Open Access Journals (Sweden)

Augusto E. Mejía Gómez

2017-04-01

Full Text Available In this work, we present the combination of two characteristics that are beneficial for solid oxide fuel cell (SOFC cathodic performance in one material. We developed and evaluated for the first time nanostructured layered perovskites of formulae LnBaCo2O6-d with Ln = Sm and Gd (SBCO and GBCO, respectively as SOFC cathodes, finding promising electrochemical properties in the intermediate temperature range. We obtained those nanostructures by using porous templates to confine the chemical reagents in regions of 200-800 nm. The performance of nanostructured SBCO and GBCO cathodes was analyzed by electrochemical impedance spectroscopy technique under different operating conditions using Gd2O3-doped CeO2 as electrolyte. We found that SBCO cathodes displayed lower area-specific resistance than GBCO ones, because bulk diffusion of oxide ions is enhanced in the former. We also found that cathodes synthesized using smaller template pores exhibited better performance.

Three-dimensional numerical simulation of wave interaction with perforated quasi-ellipse caisson

Directory of Open Access Journals (Sweden)

Yong-xue Wang

2011-03-01

Full Text Available The finite difference method and the volume of fluid (VOF method were used to develop a three-dimensional numerical model to study wave interaction with a perforated caisson. The partial cell method was adopted to solve this type of problem for the first time. The validity of the present model, with and without the presence of caisson structures, was examined by comparing the model results with experimental data. Then, the numerical model was used to investigate the effects of various wave and structure parameters on the wave force and wave runup of the perforated quasi-ellipse caisson. Compared with the solid quasi-ellipse caisson, the wave force on the perforated quasi-ellipse caisson is significantly reduced with increasing porosity of the perforated quasi-ellipse caisson. Furthermore, the perforated quasi-ellipse caisson can also reduce the wave runup, and it tends to decrease with the increase of the porosity of the perforated quasi-ellipse caisson and the relative wave height.

New Cathode Materials for Intermediate Temperature Solid Oxide Fuel Cells

Energy Technology Data Exchange (ETDEWEB)

Allan J. Jacobson

2006-09-30

the perovskite compositions that were being investigated at PNNL, in order to assess the relative importance of the intrinsic properties such as oxygen ion diffusion and surface exchange rates as predictors of performance in cell tests. We then used these measurements to select new materials for scaled up synthesis and performance evaluation in single cell tests. The results of the single cell tests than provided feedback to the materials synthesis and selection steps. In this summary, the following studies are reported: (1) Synthesis, characterization, and DC conductivity measurements of the P1 compositions La{sub 0.8}Sr{sub 0.2}FeO{sub 3-x} and La{sub 0.7}Sr{sub 0.3}FeO{sub 3-x} were completed. A combinational approach for preparing a range P1 (La,Sr)FeO{sub 3} compositions as thin films was investigated. Synthesis and heat treatment of amorphous SrFeO{sub 3-x} and LaFeO{sub 3-x} films prepared by pulsed laser deposition are described. (2) Oxygen transport properties of K1 compositions La{sub x}Pr{sub 2-x}NiO{sub 4+d} (x =2.0, 1.9, 1.2, 1.0 and 0) measured by electrical conductivity relaxation are presented in this report. Area specific resistances determined by ac impedance measurements for La{sub 2}NiO{sub 4+{delta}} and Pr{sub 2}NiO{sub 4+{delta}} on CGO are encouraging and suggest that further optimization of the electrode microstructure will enable the target to be reached. (3) The oxygen exchange kinetics of the oxygen deficient double perovskite LnBaCo{sub 2}O{sub 5.5+{delta}} (Ln=Pr and Nd) were determined by electrical conductivity relaxation. The high electronic conductivity and rapid diffusion and surface exchange kinetics of PBCO suggest its application as cathode material in intermediate temperature solid oxide fuel cells. The first complete cell measurements were performed on Ni/CGO/CGO/PBCO/CGO cells. (4) The oxygen exchange kinetics of highly epitaxial thin films of PrBaCo{sub 2}O{sub 5.5+{delta}} (PBCO) has been determined by electrical conductivity

LaNi1-xCoxO3-δ (x=0.4 to 0.7) cathodes for solid oxide fuel cells by infiltration

Science.gov (United States)

Chrzan, Aleksander; Ovtar, Simona; Chen, Ming

2016-01-01

Performance of LaNi1-xCoxO3-δ (LNC) (x=0.4 to 0.7) as a cathode in solid oxide fuel cell (SOFC) is evaluated. Symmetrical cathode/electrolyte/cathode cells for electrochemical testing are prepared by infiltration of yttria stabilized zirconia (YSZ) backbone with LNC solutions. It is showed that the cathode infiltrated with LaNi0.5Co0.5O3-δ (LNC155) has the lowest polarization resistance and activation energy, 197 mΩ cm2 at 600 °C and 0.91 eV, respectively. Therefore it is the most promising material of the LNC group for electrochemical applications. X-ray diffraction analysis revealed that none of the materials is single-phased after heat treatment at 800 °C as they contain residues of La2O3 and La2NiO4-δ

Study on modal characteristics of perforated shell using effective Young's modulus

Energy Technology Data Exchange (ETDEWEB)

Jhung, Myung Jo, E-mail: mjj@kins.re.kr [Korea Institute of Nuclear Safety, 19 Guseong-dong, Yuseong-gu, Daejeon 305-338 (Korea, Republic of); Yu, Seon Oh [Korea Institute of Nuclear Safety, 19 Guseong-dong, Yuseong-gu, Daejeon 305-338 (Korea, Republic of)

2011-06-15

Research highlights: > The effective Young's modulus of perforated shell is proposed for modal analysis. > The penetration pattern is almost negligible for effective elastic constants. > The frequency of perforated shell decreases significantly due to the hole effect. - Abstract: For the perforated cylindrical shell submerged in fluid, it is almost impossible to develop a finite element model due to the necessity of the fine meshing of the shell and the fluid at the same time. This necessitates the use of solid shell with effective material properties. Unfortunately the effective elastic constants are not found in any references even though the ASME code is suggesting those for perforated plate. Therefore in this study the effective material properties of perforated shell are suggested by performing several finite element analyses with respect to the ligament efficiencies.

About the Compatibility between High Voltage Spinel Cathode Materials and Solid Oxide Electrolytes as a Function of Temperature.

Science.gov (United States)

Miara, Lincoln; Windmüller, Anna; Tsai, Chih-Long; Richards, William D; Ma, Qianli; Uhlenbruck, Sven; Guillon, Olivier; Ceder, Gerbrand

2016-10-12

The reactivity of mixtures of high voltage spinel cathode materials Li 2 NiMn 3 O 8 , Li 2 FeMn 3 O 8 , and LiCoMnO 4 cosintered with Li 1.5 Al 0.5 Ti 1.5 (PO 4 ) 3 and Li 6.6 La 3 Zr 1.6 Ta 0.4 O 12 electrolytes is studied by thermal analysis using X-ray-diffraction and differential thermoanalysis and thermogravimetry coupled with mass spectrometry. The results are compared with predicted decomposition reactions from first-principles calculations. Decomposition of the mixtures begins at 600 °C, significantly lower than the decomposition temperature of any component, especially the electrolytes. For the cathode + Li 6.6 La 3 Zr 1.6 Ta 0.4 O 12 mixtures, lithium and oxygen from the electrolyte react with the cathodes to form highly stable Li 2 MnO 3 and then decompose to form stable and often insulating phases such as La 2 Zr 2 O 7 , La 2 O 3 , La 3 TaO 7 , TiO 2 , and LaMnO 3 which are likely to increase the interfacial impedance of a cathode composite. The decomposition reactions are identified with high fidelity by first-principles calculations. For the cathode + Li 1.5 Al 0.5 Ti 1.5 (PO 4 ) 3 mixtures, the Mn tends to oxidize to MnO 2 or Mn 2 O 3 , supplying lithium to the electrolyte for the formation of Li 3 PO 4 and metal phosphates such as AlPO 4 and LiMPO 4 (M = Mn, Ni). The results indicate that high temperature cosintering to form dense cathode composites between spinel cathodes and oxide electrolytes will produce high impedance interfacial products, complicating solid state battery manufacturing.

Stability and performance improvement of a polymer electrolyte membrane fuel cell stack by laser perforation of gas diffusion layers

Energy Technology Data Exchange (ETDEWEB)

Gerteisen, Dietmar; Sadeler, Christian [Fraunhofer Institute for Solar Energy Systems ISE, Department of Energy Technology, Heidenhofstrasse 2, 79110 Freiburg (Germany)

2010-08-15

The performance and stability of a hydrogen-driven polymer electrolyte membrane fuel cell stack (6-cell PEFC stack) are investigated with regard to pore flooding within the gas diffusion layers (GDLs). Two short stacks with various GDLs (Toray TGP-H-060 untreated and laser-perforated) were characterized at different operating conditions by several characterization techniques such as constant current load, polarization curve, chronoamperometry and chronovoltammetry. The experimental results reveal that the perforation of the cathode GDLs improves the water transport in the porous media and thus the performance as well as the stability of the operating stack in medium and high current density range. A reduced pore flooding is verified when using the customized laser-perforated GDLs. The GDL perforation has a huge potential to balance the inhomogeneous in-plane saturation conditions between the inlet and outlet area of the cell and to compensate to a certain degree the effects of temperature distribution within a stack regarding the water management. (author)

Stability and performance improvement of a polymer electrolyte membrane fuel cell stack by laser perforation of gas diffusion layers

Science.gov (United States)

Gerteisen, Dietmar; Sadeler, Christian

The performance and stability of a hydrogen-driven polymer electrolyte membrane fuel cell stack (6-cell PEFC stack) are investigated with regard to pore flooding within the gas diffusion layers (GDLs). Two short stacks with various GDLs (Toray TGP-H-060 untreated and laser-perforated) were characterized at different operating conditions by several characterization techniques such as constant current load, polarization curve, chronoamperometry and chronovoltammetry. The experimental results reveal that the perforation of the cathode GDLs improves the water transport in the porous media and thus the performance as well as the stability of the operating stack in medium and high current density range. A reduced pore flooding is verified when using the customized laser-perforated GDLs. The GDL perforation has a huge potential to balance the inhomogeneous in-plane saturation conditions between the inlet and outlet area of the cell and to compensate to a certain degree the effects of temperature distribution within a stack regarding the water management.

Pedicled perforator flaps

DEFF Research Database (Denmark)

Demirtas, Yener; Ozturk, Nuray; Kelahmetoglu, Osman

2009-01-01

Described in this study is a surgical concept that supports the "consider and use a pedicled perforator flap whenever possible and indicated" approach to reconstruct a particular skin defect. The operation is entirely free-style; the only principle is to obtain a pedicled perforator flap...... to reconstruct the defect. The perforators are marked with a hand-held Doppler probe and multiple flaps are designed. The appropriate flap is elevated after identifying the perforator(s). Dissection of the perforator(s) or complete incision of the flap margins are not mandatory if the flap is mobilized...... adequately to cover the defect. Defects measuring 3 x 3 cm up to 20 x 20 cm at diverse locations were successfully reconstructed in 20 of 21 patients with 26 flaps. Pedicled perforator flaps offer us reliable and satisfactory results of reconstruction at different anatomic territories of the body. It sounds...

Solid state cathode materials for secondary magnesium-ion batteries that are compatible with magnesium metal anodes in water-free electrolyte

International Nuclear Information System (INIS)

Crowe, Adam J.; Bartlett, Bart M.

2016-01-01

With high elemental abundance, large volumetric capacity, and dendrite-free metal deposition, magnesium metal anodes offer promise in beyond-lithium-ion batteries. However, the increased charge density associated with the divalent magnesium-ion (Mg 2+ ), relative to lithium-ion (Li + ) hinders the ion-insertion and extraction processes within many materials and structures known for lithium-ion cathodes. As a result, many recent investigations incorporate known amounts of water within the electrolyte to provide temporary solvation of the Mg 2+ , improving diffusion kinetics. Unfortunately with the addition of water, compatibility with magnesium metal anodes disappears due to forming an ion-insulating passivating layer. In this short review, recent advances in solid state cathode materials for rechargeable magnesium-ion batteries are highlighted, with a focus on cathode materials that do not require water contaminated electrolyte solutions for ion insertion and extraction processes. - Graphical abstract: In this short review, we present candidate materials for reversible Mg-battery cathodes that are compatible with magnesium metal in water-free electrolytes. The data suggest that soft, polarizable anions are required for reversible cycling.

In Situ Imaging the Oxygen Reduction Reactions of Solid State Na-O2 Batteries with CuO Nanowires as the Air Cathode.

Science.gov (United States)

Liu, Qiunan; Yang, Tingting; Du, Congcong; Tang, Yongfu; Sun, Yong; Jia, Peng; Chen, Jingzhao; Ye, Hongjun; Shen, Tongde; Peng, Qiuming; Zhang, Liqiang; Huang, Jianyu

2018-05-14

We report real time imaging of the oxygen reduction reactions (ORRs) in all solid state sodium oxygen batteries (SOBs) with CuO nanowires (NWs) as the air cathode in an aberration-corrected environmental transmission electron microscope under an oxygen environment. The ORR occurred in a distinct two-step reaction, namely, a first conversion reaction followed by a second multiple ORR. In the former, CuO was first converted to Cu 2 O and then to Cu; in the latter, NaO 2 formed first, followed by its disproportionation to Na 2 O 2 and O 2 . Concurrent with the two distinct electrochemical reactions, the CuO NWs experienced multiple consecutive large volume expansions. It is evident that the freshly formed ultrafine-grained Cu in the conversion reaction catalyzed the latter one-electron-transfer ORR, leading to the formation of NaO 2 . Remarkably, no carbonate formation was detected in the oxygen cathode after cycling due to the absence of carbon source in the whole battery setup. These results provide fundamental understanding into the oxygen chemistry in the carbonless air cathode in all solid state Na-O 2 batteries.

Enhanced electrochemical performance of the solid oxide fuel cell cathode using Ca3Co4O9+δ

DEFF Research Database (Denmark)

Samson, Alfred Junio; Søgaard, Martin; Van Nong, Ngo

2011-01-01

This paper reports on the electrochemical performance of an SOFC cathode for potential use in intermediate-temperature solid oxide fuel cells (IT-SOFCs) using the oxygen non-stoichiometric misfit-layered cobaltite Ca3Co4O9+δ or composites of Ca3Co4O9+δ with Ce0.9Gd0.1O1.95 (CGO/Ca3Co4O9+δ......). Electrochemical impedance spectroscopy revealed that symmetric cells with an electrode of pure Ca3Co4O9+δ exhibit a cathode polarization resistance (Rp) of 12.4 Ω cm2, at 600 °C in air. Strikingly, Rp of the composite CGO/Ca3Co4O9+δ with 50 vol.% CGO was reduced by a factor of 19 (i.e. Rp = 0.64 Ω cm2......), the lowest value reported so far for the Ca3Co4O9 family of compounds. These findings together with the reported thermal expansion coefficient, good compatibility with CGO and chemical durability of this material suggest that it is a promising candidate cathode for IT-SOFCs....

Antimony doped barium strontium ferrite perovskites as novel cathodes for intermediate-temperature solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Ling, Yihan, E-mail: lyhyy@mail.ustc.edu.cn [School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, 221116 (China); Lu, Xiaoyong [China Anhui Key Laboratory of Low Temperature Co-fired Materials, Department of Chemistry, Huainan Normal University, Huainan, Anhui, 232001 (China); Niu, Jinan; Chen, Hui [School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, 221116 (China); Ding, Yanzhi [China Anhui Key Laboratory of Low Temperature Co-fired Materials, Department of Chemistry, Huainan Normal University, Huainan, Anhui, 232001 (China); Ou, Xuemei [School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, 221116 (China); Zhao, Ling [Department of Material Science and Chemistry, China University of Geosciences, Wuhan, 430074 (China)

2016-05-05

Antimony was doped to barium strontium ferrite to produce ferrite-based perovskites with a composition of Ba{sub 0.5}Sr{sub 0.5}Fe{sub 1−x}Sb{sub x}O{sub 3−δ} (x = 0.0, 0.05, 0.1) as novel cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The perovskite properties including oxygen nonstoichiometry (δ), mean valence of B-site, tolerance factors, thermal expansion coefficient (TEC) and electrical conductivity (σ) are explored as a function of antimony content. By defect chemistry analysis, the TECs decrease since the variable oxygen vacancy concentration is decreased by Sb doping, and σ decreases with x due to the reduced charge concentration of Fe{sup 4+} content. Consequently, the electrochemical performance was substantially improved and the interfacial polarization resistance was reduced from 0.213 to 0.120 Ωcm{sup 2} at 700 °C with Sb doping. The perovskite with x = 1.0 is suggested as the most promising composition as SOFC cathode material. - Highlights: • Antimony is doped to barium strontium ferrite to produce novel cathodes. • δ, TECs and σ are evaluated as a function of antimony content. • The electrochemical performance is substantially improved with antimony doping.

Semi-solid electrodes having high rate capability

Energy Technology Data Exchange (ETDEWEB)

Chiang, Yet-Ming; Duduta, Mihai; Holman, Richard; Limthongkul, Pimpa; Tan, Taison

2017-11-28

Embodiments described herein relate generally to electrochemical cells having high rate capability, and more particularly to devices, systems and methods of producing high capacity and high rate capability batteries having relatively thick semi-solid electrodes. In some embodiments, an electrochemical cell includes an anode and a semi-solid cathode. The semi-solid cathode includes a suspension of an active material of about 35% to about 75% by volume of an active material and about 0.5% to about 8% by volume of a conductive material in a non-aqueous liquid electrolyte. An ion-permeable membrane is disposed between the anode and the semi-solid cathode. The semi-solid cathode has a thickness of about 250 .mu.m to about 2,000 .mu.m, and the electrochemical cell has an area specific capacity of at least about 7 mAh/cm.sup.2 at a C-rate of C/4. In some embodiments, the semi-solid cathode slurry has a mixing index of at least about 0.9.

Synthesis and characterization of gadolinia-doped ceria-silver cermet cathode material for solid oxide fuel cells

International Nuclear Information System (INIS)

Datta, Pradyot; Majewski, Peter; Aldinger, Fritz

2008-01-01

A series of Ce 0.9 Gd 0.1 O 2-δ -Ag cermets with different Ag contents were prepared by conventional sintering process aiming at assessing the suitability of using them as cathode material for solid oxide fuel cell (SOFC) with Gadolinia-doped ceria electrolyte. The chemical compatibility between Ce 0.9 Gd 0.1 O 2-δ (CGO) and Ag was investigated by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Thermal expansion coefficients of the cermets were measured as a function of Ag content and were found to increase with metallic content. Although oxygen adsorption at the surface of the cermets could be detected, no reaction or solid solubility between CGO and Ag was found

Mechanistic modelling of a cathode-supported solid oxide fuel cell. Paper no. IGEC-1-103

International Nuclear Information System (INIS)

Suwanwarangkul, R.; Croiset, E.; Pritzker, M.D.; Fowler, M.W.; Douglas, P.L.; Entchev, E.

2005-01-01

A model for a cathode-supported tubular solid oxide fuel cell operating with humidified H 2 has been developed. Momentum-, mass-, energy- and charge-transport equations coupled with electrochemical reactions (H 2 oxidation and O 2 reduction) are considered in the model. The model also takes into account the radiative heat transfer between the cell and air-preheating tube. The model is validated against published experimental data ands shows a good agreement. The distributions of temperature, current density, reversible cell voltage, overpotential and species mole fractions within the cell are discussed in detail. (author)

Synthesis and characterization of Co-doped lanthanum nickelate perovskites for solid oxide fuel cell cathode material

International Nuclear Information System (INIS)

Chavez G, L.; Hinojosa R, M.; Medina L, B.; Ringuede, A.; Cassir, M.; Vannier, R. N.

2017-01-01

In the perovskite structures widely investigated and used as solid oxide fuel cells cathodes, oxygen reduction is mainly limited to the triple phase boundary (TPB), where oxygen (air), electrode and electrolyte are in contact. It is possible via the sol-gel modified Pechini method to: 1) control the material grain size, which can increase TPBs, 2) produce a homogenous material and 3) obtain a cathode material in a faster way compared with the solid state route. LaNi_xCo_1_-_xO_3 (x = 0.3, 0.5, 0.7) were synthesized by the modified Pechini method. The perovskite phase formation began at 350 degrees Celsius and the presence of pure LaNi_0_._7Co_0_._3O_3, LaNi_0_._5Co_0_._5O_3 and LaNi_0_._3Co_0_._7O_3 structures was evidenced by high temperature X-ray diffraction (Ht-XRD) measurements. Scanning electron microscopy (Sem) micrographs showed that the microstructure evolves with the amount of cobalt from a coalesced to an open structure. Electrochemical impedance spectroscopy (EIS) on symmetrical cells LaNi_xCo_1_-_xO_3/YSZ (Yttria-stabilized zirconia)/LaNi_xCo_1_-_xO_3 showed that the highest ASR (area specific resistance) is obtained with x = 0.3, whereas ASR values are similar for x = 0.5 and 0.7 at temperatures higher than 600 degrees Celsius. At temperatures lower than 600 degrees Celsius, ASR is the lowest for LaNi_0_._5Co_0_._5O_3, showing that this composition with intermediate porosity appears as a good choice for and intermediate-temperature solid oxid fuel cell. (Author)

High-performance electrodes for reduced temperature solid oxide fuel cells with doped lanthanum gallate electrolyte. II. La(Sr)CoO 3 cathode

Science.gov (United States)

Inagaki, Toru; Miura, Kazuhiro; Yoshida, Hiroyuki; Maric, Radenka; Ohara, Satoshi; Zhang, Xinge; Mukai, Kazuo; Fukui, Takehisa

The reduced temperature solid oxide fuel cell (SOFC) with 0.5 mm thick La 0.9Sr 0.1Ga 0.8Mg 0.2O 3- α (LSGM) electrolyte, La 0.6Sr 0.4CoO 3- δ (LSCo) cathode, and Ni-(CeO 2) 0.8(SmO 1.5) 0.2 (SDC) cermet anode showed an excellent initial performance, and high maximum power density, 0.47 W/cm 2, at 800°C. The results were comparable to those for the conventional SOFC with yttria-stabilized zirconia (YSZ) electrolyte, La(Sr)MnO 3-YSZ cathode and Ni-YSZ cermet anode at 1000°C. Using an LSCo powder prepared by spray pyrolysis, and selecting appropriate sintering temperatures, the lowest cathodic polarization of about 25 mV at 300 mA/cm 2 was measured for a cathode prepared by sintering at 1000°C. Life time cell test results, however, showed that the polarization of the LSCo cathode increased with operating time. From EPMA results, this behavior was considered to be related to the interdiffusion of the elements at the cathode/electrolyte interface. Calcination of LSCo powder could be a possible way to suppress this interdiffusion at the interface.

Stationary semi-solid battery module and method of manufacture

Science.gov (United States)

Slocum, Alexander; Doherty, Tristan; Bazzarella, Ricardo; Cross, III, James C.; Limthongkul, Pimpa; Duduta, Mihai; Disko, Jeffry; Yang, Allen; Wilder, Throop; Carter, William Craig; Chiang, Yet-Ming

2015-12-01

A method of manufacturing an electrochemical cell includes transferring an anode semi-solid suspension to an anode compartment defined at least in part by an anode current collector and an separator spaced apart from the anode collector. The method also includes transferring a cathode semi-solid suspension to a cathode compartment defined at least in part by a cathode current collector and the separator spaced apart from the cathode collector. The transferring of the anode semi-solid suspension to the anode compartment and the cathode semi-solid to the cathode compartment is such that a difference between a minimum distance and a maximum distance between the anode current collector and the separator is maintained within a predetermined tolerance. The method includes sealing the anode compartment and the cathode compartment.

Cathode Composition in a Saltwater Metal-Air Battery

Directory of Open Access Journals (Sweden)

William Shen

2017-01-01

Full Text Available Metal-air batteries consist of a solid metal anode and an oxygen cathode of ambient air, typically separated by an aqueous electrolyte. Here, simple saltwater-based models of aluminum-air and zinc-air cells are used to determine the differences between theoretical cell electric potentials and experimental electric potentials. A substantial difference is observed. It is also found that the metal cathode material is crucial to cell electric potential, despite the cathode not participating in the net reaction. Finally, the material composition of the cathode appears to have a more significant impact on cell potential than the submerged surface area of the cathode.

Development and testing of anode-supported solid oxide fuel cells with slurry-coated electrolyte and cathode

Energy Technology Data Exchange (ETDEWEB)

Muccillo, R.; Muccillo, E.N.S.; Fonseca, F.C.; Franca, Y.V.; Porfirio, T.C. [Centro de Ciencia e Tecnologia de Materiais, Instituto de Pesquisas Energeticas e Nucleares, C.P. 11049, Pinheiros, S. Paulo, SP 05422-970 (Brazil); de Florio, D.Z. [Instituto de Quimica, UNESP, R. Prof. Francisco Degni s/n, Araraquara, SP 14801-970 (Brazil); Berton, M.A.C.; Garcia, C.M. [Instituto de Tecnologia para o Desenvolvimento, DPMA, C.P. 19067, Curitiba, PR 81531-980 (Brazil)

2006-06-01

A laboratory setup was designed and put into operation for the development of solid oxide fuel cells (SOFCs). The whole project consisted of the preparation of the component materials: anode, cathode and electrolyte, and the buildup of a hydrogen leaking-free sample chamber with platinum leads and current collectors for measuring the electrochemical properties of single SOFCs. Several anode-supported single SOFCs of the type (ZrO{sub 2}:Y{sub 2}O{sub 3}+NiO) thick anode/(ZrO{sub 2}:Y{sub 2}O{sub 3}) thin electrolyte/(La{sub 0.65}Sr{sub 0.35}MnO{sub 3}+ZrO{sub 2}:Y{sub 2}O{sub 3}) thin cathode have been prepared and tested at 700 and 800{sup o}C after in situ H{sub 2} anode reduction. The main results show that the slurry-coating method resulted in single-cells with good reproducibility and reasonable performance, suggesting that this method can be considered for fabrication of SOFCs. (author)

Combined theoretical and experimental analysis of processes determining cathode performance in solid oxide fuel cells.

Science.gov (United States)

Kuklja, M M; Kotomin, E A; Merkle, R; Mastrikov, Yu A; Maier, J

2013-04-21

Solid oxide fuel cells (SOFC) are under intensive investigation since the 1980's as these devices open the way for ecologically clean direct conversion of the chemical energy into electricity, avoiding the efficiency limitation by Carnot's cycle for thermochemical conversion. However, the practical development of SOFC faces a number of unresolved fundamental problems, in particular concerning the kinetics of the electrode reactions, especially oxygen reduction reaction. We review recent experimental and theoretical achievements in the current understanding of the cathode performance by exploring and comparing mostly three materials: (La,Sr)MnO3 (LSM), (La,Sr)(Co,Fe)O3 (LSCF) and (Ba,Sr)(Co,Fe)O3 (BSCF). Special attention is paid to a critical evaluation of advantages and disadvantages of BSCF, which shows the best cathode kinetics known so far for oxides. We demonstrate that it is the combined experimental and theoretical analysis of all major elementary steps of the oxygen reduction reaction which allows us to predict the rate determining steps for a given material under specific operational conditions and thus control and improve SOFC performance.

Cobalt-free cathode material SrFe{sub 0.9}Nb{sub 0.1}O{sub 3-{delta}} for intermediate-temperature solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Zhou, Qingjun [State Key Laboratory of Superhard Materials and College of Physics, Jilin University, Changchun 130012 (China); College of Science, Civil Aviation University of China, Tianjin 300300 (China); Zhang, Leilei; He, Tianmin [State Key Laboratory of Superhard Materials and College of Physics, Jilin University, Changchun 130012 (China)

2010-02-15

A cobalt-free cubic perovskite oxide, SrFe{sub 0.9}Nb{sub 0.1}O{sub 3-{delta}} (SFN) was investigated as a cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). XRD results showed that SFN cathode was chemically compatible with the electrolyte Sm{sub 0.2}Ce{sub 0.8}O{sub 1.9} (SDC) for temperatures up to 1050 C. The electrical conductivity of SFN sample reached 34-70 S cm{sup -1} in the commonly operated temperatures of IT-SOFCs (600-800 C). The area specific resistance was 0.138 {omega} cm{sup 2} for SFN cathode on SDC electrolyte at 750 C. A maximum power density of 407 mW cm{sup -2} was obtained at 800 C for single-cell with 300 {mu}m thick SDC electrolyte and SFN cathode. (author)

Differentiating perforated from non-perforated appendicitis on contrast-enhanced magnetic resonance imaging

International Nuclear Information System (INIS)

Rosenbaum, Daniel G.; Kovanlikaya, Arzu; Askin, Gulce; Beneck, Debra M.

2017-01-01

The role of magnetic resonance imaging (MRI) in pediatric appendicitis is increasing; MRI findings predictive of appendiceal perforation have not been specifically evaluated. To assess the performance of MRI in differentiating perforated from non-perforated appendicitis. A retrospective review of pediatric patients undergoing contrast-enhanced MRI and subsequent appendectomy was performed, with surgicopathological confirmation of perforation. Appendiceal diameter and the following 10 MRI findings were assessed: appendiceal restricted diffusion, wall defect, appendicolith, periappendiceal free fluid, remote free fluid, restricted diffusion within free fluid, abscess, peritoneal enhancement, ileocecal wall thickening and ileus. Two-sample t-test and chi-square tests were used to analyze continuous and discrete data, respectively. Sensitivity and specificity for individual MRI findings were calculated and optimal thresholds for measures of accuracy were selected. Seventy-seven patients (mean age: 12.2 years) with appendicitis were included, of whom 22 had perforation. The perforated group had a larger mean appendiceal diameter and mean number of MRI findings than the non-perforated group (12.3 mm vs. 8.6 mm; 5.0 vs. 2.0, respectively). Abscess, wall defect and restricted diffusion within free fluid had the greatest specificity for perforation (1.00, 1.00 and 0.96, respectively) but low sensitivity (0.36, 0.25 and 0.32, respectively). The receiver operator characteristic curve for total number of MRI findings had an area under the curve of 0.92, with an optimal threshold of 3.5. A threshold of any 4 findings had the best ability to accurately discriminate between perforated and non-perforated cases, with a sensitivity of 82% and specificity of 85%. Contrast-enhanced MRI can differentiate perforated from non-perforated appendicitis. The presence of multiple findings increases diagnostic accuracy, with a threshold of any four findings optimally discriminating between

Differentiating perforated from non-perforated appendicitis on contrast-enhanced magnetic resonance imaging.

Science.gov (United States)

Rosenbaum, Daniel G; Askin, Gulce; Beneck, Debra M; Kovanlikaya, Arzu

2017-10-01

The role of magnetic resonance imaging (MRI) in pediatric appendicitis is increasing; MRI findings predictive of appendiceal perforation have not been specifically evaluated. To assess the performance of MRI in differentiating perforated from non-perforated appendicitis. A retrospective review of pediatric patients undergoing contrast-enhanced MRI and subsequent appendectomy was performed, with surgicopathological confirmation of perforation. Appendiceal diameter and the following 10 MRI findings were assessed: appendiceal restricted diffusion, wall defect, appendicolith, periappendiceal free fluid, remote free fluid, restricted diffusion within free fluid, abscess, peritoneal enhancement, ileocecal wall thickening and ileus. Two-sample t-test and chi-square tests were used to analyze continuous and discrete data, respectively. Sensitivity and specificity for individual MRI findings were calculated and optimal thresholds for measures of accuracy were selected. Seventy-seven patients (mean age: 12.2 years) with appendicitis were included, of whom 22 had perforation. The perforated group had a larger mean appendiceal diameter and mean number of MRI findings than the non-perforated group (12.3 mm vs. 8.6 mm; 5.0 vs. 2.0, respectively). Abscess, wall defect and restricted diffusion within free fluid had the greatest specificity for perforation (1.00, 1.00 and 0.96, respectively) but low sensitivity (0.36, 0.25 and 0.32, respectively). The receiver operator characteristic curve for total number of MRI findings had an area under the curve of 0.92, with an optimal threshold of 3.5. A threshold of any 4 findings had the best ability to accurately discriminate between perforated and non-perforated cases, with a sensitivity of 82% and specificity of 85%. Contrast-enhanced MRI can differentiate perforated from non-perforated appendicitis. The presence of multiple findings increases diagnostic accuracy, with a threshold of any four findings optimally discriminating between

Differentiating perforated from non-perforated appendicitis on contrast-enhanced magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Rosenbaum, Daniel G.; Kovanlikaya, Arzu [New York-Presbyterian Hospital/Weill Cornell Medicine, Division of Pediatric Radiology, New York, NY (United States); Askin, Gulce [Weill Cornell Medical College, Division of Biostatistics and Epidemiology, New York, NY (United States); Beneck, Debra M. [New York-Presbyterian Hospital/Weill Cornell Medicine, Department of Pathology, New York, NY (United States)

2017-10-15

The role of magnetic resonance imaging (MRI) in pediatric appendicitis is increasing; MRI findings predictive of appendiceal perforation have not been specifically evaluated. To assess the performance of MRI in differentiating perforated from non-perforated appendicitis. A retrospective review of pediatric patients undergoing contrast-enhanced MRI and subsequent appendectomy was performed, with surgicopathological confirmation of perforation. Appendiceal diameter and the following 10 MRI findings were assessed: appendiceal restricted diffusion, wall defect, appendicolith, periappendiceal free fluid, remote free fluid, restricted diffusion within free fluid, abscess, peritoneal enhancement, ileocecal wall thickening and ileus. Two-sample t-test and chi-square tests were used to analyze continuous and discrete data, respectively. Sensitivity and specificity for individual MRI findings were calculated and optimal thresholds for measures of accuracy were selected. Seventy-seven patients (mean age: 12.2 years) with appendicitis were included, of whom 22 had perforation. The perforated group had a larger mean appendiceal diameter and mean number of MRI findings than the non-perforated group (12.3 mm vs. 8.6 mm; 5.0 vs. 2.0, respectively). Abscess, wall defect and restricted diffusion within free fluid had the greatest specificity for perforation (1.00, 1.00 and 0.96, respectively) but low sensitivity (0.36, 0.25 and 0.32, respectively). The receiver operator characteristic curve for total number of MRI findings had an area under the curve of 0.92, with an optimal threshold of 3.5. A threshold of any 4 findings had the best ability to accurately discriminate between perforated and non-perforated cases, with a sensitivity of 82% and specificity of 85%. Contrast-enhanced MRI can differentiate perforated from non-perforated appendicitis. The presence of multiple findings increases diagnostic accuracy, with a threshold of any four findings optimally discriminating between

Synthesis and characterization of Co-doped lanthanum nickelate perovskites for solid oxide fuel cell cathode material

Energy Technology Data Exchange (ETDEWEB)

Chavez G, L.; Hinojosa R, M. [Universidad Autonoma de Nuevo Leon, Ciudad Universitaria, San Nicolas de los Garza, 66450 Nuevo Leon (Mexico); Medina L, B.; Ringuede, A.; Cassir, M. [Institut de Recherche de Chimie Paris, CNRS-Chimie ParisTech, 11 rue Pierre et Marie Curie, 75005 Paris (France); Vannier, R. N., E-mail: leonardo.chavezgr@uanl.edu.mx [Unite de Catalyse et de Chimie du Solide, UMR 8181 CNRS, 59655, Villeneuve d Ascq Cedex (France)

2017-11-01

In the perovskite structures widely investigated and used as solid oxide fuel cells cathodes, oxygen reduction is mainly limited to the triple phase boundary (TPB), where oxygen (air), electrode and electrolyte are in contact. It is possible via the sol-gel modified Pechini method to: 1) control the material grain size, which can increase TPBs, 2) produce a homogenous material and 3) obtain a cathode material in a faster way compared with the solid state route. LaNi{sub x}Co{sub 1-x}O{sub 3} (x = 0.3, 0.5, 0.7) were synthesized by the modified Pechini method. The perovskite phase formation began at 350 degrees Celsius and the presence of pure LaNi{sub 0.7}Co{sub 0.3}O{sub 3}, LaNi{sub 0.5}Co{sub 0.5}O{sub 3} and LaNi{sub 0.3}Co{sub 0.7}O{sub 3} structures was evidenced by high temperature X-ray diffraction (Ht-XRD) measurements. Scanning electron microscopy (Sem) micrographs showed that the microstructure evolves with the amount of cobalt from a coalesced to an open structure. Electrochemical impedance spectroscopy (EIS) on symmetrical cells LaNi{sub x}Co{sub 1-x}O{sub 3}/YSZ (Yttria-stabilized zirconia)/LaNi{sub x}Co{sub 1-x}O{sub 3} showed that the highest ASR (area specific resistance) is obtained with x = 0.3, whereas ASR values are similar for x = 0.5 and 0.7 at temperatures higher than 600 degrees Celsius. At temperatures lower than 600 degrees Celsius, ASR is the lowest for LaNi{sub 0.5}Co{sub 0.5}O{sub 3}, showing that this composition with intermediate porosity appears as a good choice for and intermediate-temperature solid oxid fuel cell. (Author)

Spontaneous external gallbladder perforation

International Nuclear Information System (INIS)

Noeldge, G.; Wimmer, B.; Kirchner, R.

1981-01-01

Spontaneous perforation of the gallbladder is one complication of cholelithiasis. There is a greater occurence of free perforation in the peritoneal cavity with bilary pertonitis, followed by the perforation into the stomach, small intestine and colon. A single case of the nowadays rare spontaneous perforation in and through the abdominal wall will be reported. Spontaneous gallbladder perforation appears nearly asymptomatic in its clinical course because of absent biliary peritonitis. (orig.) [de

The Versatile Modiolus Perforator Flap

DEFF Research Database (Denmark)

Gunnarsson, Gudjon Leifur; Thomsen, Jorn Bo

2016-01-01

BACKGROUND: Perforator flaps are well established, and their usefulness as freestyle island flaps is recognized. The whereabouts of vascular perforators and classification of perforator flaps in the face are a debated subject, despite several anatomical studies showing similar consistency. In our...... experience using freestyle facial perforator flaps, we have located areas where perforators are consistently found. This study is focused on a particular perforator lateral to the angle of the mouth; the modiolus and the versatile modiolus perforator flap. METHODS: A cohort case series of 14 modiolus...... perforator flap reconstructions in 14 patients and a color Doppler ultrasonography localization of the modiolus perforator in 10 volunteers. RESULTS: All 14 flaps were successfully used to reconstruct the defects involved, and the location of the perforator was at the level of the modiolus as predicted...

La{sub 0.84}Sr{sub 0.16}MnO{sub 3-{delta}} cathodes impregnated with Bi{sub 1.4}Er{sub 0.6}O{sub 3} for intermediate-temperature solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Li, Junliang; Wang, Shaorong; Wang, Zhenrong; Liu, Renzhu; Wen, Tinglian; Wen, Zhaoyin [The Key Laboratory of Energy Conversion Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

2009-12-01

La{sub 0.84}Sr{sub 0.16}MnO{sub 3-{delta}}-Bi{sub 1.4}Er{sub 0.6}O{sub 3} (LSM-ESB) composite cathodes are fabricated by impregnating LSM electronic conducting matrix with the ion-conducting ESB for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The performance of LSM-ESB cathodes is investigated at temperatures below 750 C by AC impedance spectroscopy. The ion-impregnation of ESB significantly enhances the electrocatalytic activity of the LSM electrodes for the oxygen reduction reactions, and the ion-impregnated LSM-ESB composite cathodes show excellent performance. At 750 C, the value of the cathode polarization resistance (R{sub p}) is only 0.11 {omega} cm{sup 2} for an ion-impregnated LSM-ESB cathode, which also shows high stability during a period of 200 h. For the performance testing of single cells, the maximum power density is 0.74 W cm{sup -2} at 700 C for a cell with the LSM-ESB cathode. The results demonstrate the ion-impregnated LSM-ESB is one of the promising cathode materials for intermediate-temperature solid oxide fuel cells. (author)

Salmonella intestinal perforation: (27 perforations in one patient, 14 perforations in another Are the goal posts changing?

Directory of Open Access Journals (Sweden)

Adeniran J

2005-01-01

Full Text Available The pathology of salmonellosis after a faeco-oral transmission was first clearly described by Jenner in 1850. Over the years, the pathological manifestations in different tissues of the body have been described. The ileum is however mostly involved leading to enlarged Peyer′s patches, ulceration, and sometimes bleeding and perforation. Efforts at control have largely been improvement in public water supply, safe disposal of waste, and general public health measures. Despite these measures, intestinal perforation from salmonellosis remains the commonest cause of emergency operation in children above 3 years. The incidence continues to rise, so also the mortality, despite new antibiotics and improvement in facilities in the hospitals. Even more disturbing is that we now see more perforations per patient, and more involvement of the colon. Three recently managed patients with multiple ileal/colonic perforations were reviewed. Presenting problems, delay in referral, choice of antibiotics and postoperative complications were noted. One patient had 27 perforations and another 14 perforations. Both survived. Is salmonella changing? Are our patients changing? Is the environment changing? Are the goal posts changing? This article details our recent experience with this dreadful disease, reviews the new literature and makes suggestions for the way forwards.

Prediction of inelastic behavior and creep-fatigue life of perforated plates

International Nuclear Information System (INIS)

Igari, Toshihide; Yamauchi, Masafumi; Nomura, Shinichi.

1992-01-01

Prediction methods of macroscopic and local stress-strain behaviors of perforated plates in plastic and creep regime are proposed in this paper, and are applied to the creep-fatigue life prediction of perforated plates. Both equivalent-solid-plate properties corresponding to the macroscopic behavior and the stress-strain concentration around a hole were obtained by assuming the analogy between plasticity and creep and also by extending the authors' proposal in creep condition. The perforated plates which were made of Hastelloy XR were subjected to the strain-controlled cyclic test at 950degC in air in order to experimentally obtain the macroscopic behavior such as the cyclic stress-strain curve and creep-fatigue life around a hole. The results obtained are summarized as follows. (1) The macroscopic behavior of perforated plates including cyclic stress-strain behavior and relaxation is predictable by using the proposed method in this paper. (2) The creep-fatigue life around a hole can be predicted by using the proposed method for stress-strain concentration around a hole. (author)

High Performance Proton-Conducting Solid Oxide Fuel Cells with a Layered Perovskite GdBaCuCoO5+ x Cathode

Science.gov (United States)

Zhang, Xiaozhen; Jiang, Yuhua; Hu, Xuebing; Sun, Liangliang; Ling, Yihan

2018-03-01

Proton-conducting solid oxide fuel cell (H-SOFC) based on layered perovskite type GdBaCuCoO5+x (GBCC) cathode was fabricated with in situ drop-coating BaZr0.1Ce0.7Y0.2O3-δ (BZCY) electrolyte membrane. The influences of Cu doping into Co sites of GdBaCo2O5+ x on the electrical conductivity and conduction mechanism, thermal expansion property and electrochemical performance of cathode materials and corresponding single cell were investigated. Results show that the electrical conductivity decreased and the conduction mechanism would gradually transform to the semiconductor-like behavior. A high maximum power density of 480 mW cm-2 was obtained for the anode supported NiO-BZCY/NiO-BZCY/BZCY/GBCC single cells with wet H2 fuel at 700 °C. The corresponding polarization resistance was as low as 0.17 Ω cm2. The excellent electrochemical performance of as-prepared single cell indicates that GBCC is a good candidate of cathode materials for H-SOFCs.

RF Electron Gun with Driven Plasma Cathode

CERN Document Server

Khodak, Igor

2005-01-01

It's known that RF guns with plasma cathodes based on solid-state dielectrics are able to generate an intense electron beam. In this paper we describe results of experimental investigation of the single cavity S-band RF gun with driven plasma cathode. The experimental sample of the cathode based on ferroelectric ceramics has been designed. Special design of the cathode permits to separate spatially processes of plasma development and electron acceleration. It has been obtained at RF gun output electron beam with particle energy ~500 keV, pulse current of 4 A and pulse duration of 80 ns. Results of experimental study of beam parameters are referred in. The gun is purposed to be applied as the intense electron beam source for electron linacs.

Investigation on the Acoustic Absorption of Flexible Micro-Perforated Panel with Ultra-Micro Perforations

Science.gov (United States)

Li, Guoxin; Tang, Xiaoning; Zhang, Xiaoxiao; Qian, Y. J.; Kong, Deyi

2017-11-01

Flexible micro-perforated panel has unique advantages in noise reduction due to its good flexibility compared with traditional rigid micro-perforated panel. In this paper, flexible micro-perforated panel was prepared by computer numerical control (CNC) milling machine. Three kinds of plastics including polyvinylchloride (PVC), polyethylene terephthalate (PET), and polyimide (PI) were taken as the matrix materials to prepare flexible micro-perforated panel. It has been found that flexible micro-perforated panel made of PET possessing good porosity and proper density, elastic modulus and poisson ratio exhibited the best acoustic absorption properties. The effects of various structural parameters including perforation diameter, perforation ratio, thickness and air gap have also been investigated, which would be helpful to the optimization of acoustic absorption properties.

Synthesis and characterization of cobaltite nanotubes for solid-oxide fuel cell cathodes

Energy Technology Data Exchange (ETDEWEB)

Napolitano, F; Baque, L; Troiani, H; Granada, M; Serquis, A, E-mail: aserquis@cab.cnea.gov.a [Instituto Balseiro-Centro Atomico Bariloche and CONICET, San Carlos de Bariloche (Argentina)

2009-05-01

La{sub 1-x}Sr{sub x}Co{sub 1-y}FeyO{sub 3-d}elta oxides are good candidates for solid oxide fuel cell (SOFC) cathodes because these materials present high ionic and electronic conductivity, and compatibility with Cerium Gadolinium Oxide (CGO) electrolytes allowing a lower operation temperature. In this work, we report the synthesis of La{sub 0.4}Sr{sub 0.6}Co{sub 0.8}Fe{sub 0.2}O{sub 3-d}elta (LSCF) nanotubes prepared by a porous polycarbonate membrane approach, obtaining different microstructures depending on sintering conditions. The structure and morphology of the nanotubes and deposited films were characterized by X-ray diffraction, transmission and scanning microscopy. Finally, we obtained nanostructured films of vertically aligned LSCF tubes deposited over the whole surface of CGO pellets with diameter up to 2.5cm in a direct and single step process.

Model for solid oxide fuel cell cathodes prepared by infiltration

DEFF Research Database (Denmark)

Samson, Alfred Junio; Søgaard, Martin; Hendriksen, Peter Vang

2017-01-01

A 1-dimensional model of a cathode has been developed in order to understand and predict the performance of cathodes prepared by infiltration of La0.6Sr0.4Co1.05O3-δ (LSC) into porous backbones of Ce0.9Gd0.1O1.95 (CGO). The model accounts for the mixed ionic and electronic conductivity of LSC......, ionic conductivity of CGO, gas transport in the porous cathode, and the oxygen reduction reaction at the surface of percolated LSC. Geometrical variations are applied to reflect a changing microstructure of LSC under varying firing temperatures. Using microstructural parameters obtained from detailed...... scanning electron microscopy and simulations of the measured polarization resistances, an expression for the area specific resistance (rp) associated with the oxygen exchange on the surface of the infiltrated LSC particles was extracted and compared with literature values. A series of microstructural...

Triple-conducting layered perovskites as cathode materials for proton-conducting solid oxide fuel cells.

Science.gov (United States)

Kim, Junyoung; Sengodan, Sivaprakash; Kwon, Goeun; Ding, Dong; Shin, Jeeyoung; Liu, Meilin; Kim, Guntae

2014-10-01

We report on an excellent anode-supported H(+) -SOFC material system using a triple conducting (H(+) /O(2-) /e(-) ) oxide (TCO) as a cathode material for H(+) -SOFCs. Generally, mixed ionic (O(2-) ) and electronic conductors (MIECs) have been selected as the cathode material of H(+) -SOFCs. In an H(+) -SOFC system, however, MIEC cathodes limit the electrochemically active sites to the interface between the proton conducting electrolyte and the cathode. New approaches to the tailoring of cathode materials for H(+) -SOFCs should therefore be considered. TCOs can effectively extend the electrochemically active sites from the interface between the cathode and the electrolyte to the entire surface of the cathode. The electrochemical performance of NBSCF/BZCYYb/BZCYYb-NiO shows excellent long term stability for 500 h at 1023 K with high power density of 1.61 W cm(-2) . © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transport parameters of thin, supported cathode layers in solid oxide fuel cells (SOFCs); Transportparameter duenner, getraegerter Kathodenschichten der oxidkeramischen Brennstoffzelle

Energy Technology Data Exchange (ETDEWEB)

Wedershoven, Christian

2010-12-22

The aim of this work was to determine the transport properties of thin cathode layers, which are part of the composite layer of a fabricated anode-supported solid oxide fuel cell (SOFC). The transport properties of the anode and cathode have a significant influence on the electrochemical performance of a fuel cell stack and therefore represent an important parameter when designing fuel cell stacks. In order to determine the transport parameters of the cathode layers in a fabricated SOFC, it is necessary to permeate the thin cathode layer deposited on the gas-tight electrolyte with a defined gas transport. These thin cathode layers cannot be fabricated as mechanically stable single layers and cannot therefore be investigated in the diffusion and permeation experiments usually used to determine transport parameters. The setup of these experiments - particularly the sample holder - was therefore altered in this work. The result of this altered setup was a three-dimensional flow configuration. Compared to the conventional setup, it was no longer possible to describe the gas transport in the experiments with an analytical one-dimensional solution. A numerical solution process had to be used to evaluate the measurements. The new setup permitted a sufficiently symmetrical gas distribution and thus allowed the description of the transport to be reduced to a two-dimensional description, which significantly reduced the computational effort required to evaluate the measurements. For pressure-induced transport, a parametrized coherent expression of transport could be derived. This expression is equivalent to the analytical description of the transport in conventional measurement setups, with the exception of parameters that describe the geometry of the gas diffusion. In this case, a numerical process is not necessary for the evaluation. Using the transport parameters of mechanically stable anode substrates, which can be measured both in the old and the new setups, the old and

Anode Supported Solid Oxide Fuel Cells - Deconvolution of Degradation into Cathode and Anode Contributions

DEFF Research Database (Denmark)

Hagen, Anke; Liu, Yi-Lin; Barfod, Rasmus

2007-01-01

The degradation of anode supported cells was studied over 1500 h as function of cell polarization either in air or oxygen on the cathode. Based on impedance analysis, contributions of anode and cathode to the increase of total resistance were assigned. Accordingly, the degradation rates...... of the cathode were strongly dependent on the pO(2); they were significantly smaller when testing in oxygen compared to air. Microstructural analysis of the cathode/electrolyte interface of a not-tested reference cell carried out after removal of the cathode showed sharp craters on the electrolyte surface where...

Effect of perforation on the sound transmission through a double-walled cylindrical shell

Science.gov (United States)

Zhang, Qunlin; Mao, Yijun; Qi, Datong

2017-12-01

An analytical model is developed to study the sound transmission loss through a general double-walled cylindrical shell system with one or two walls perforated, which is excited by a plane wave in the presence of external mean flow. The shell motion is governed by the classical Donnell's thin shell theory, and the mean particle velocity model is employed to describe boundary conditions at interfaces between the shells and fluid media. In contrast to the conventional solid double-walled shell system, numerical results show that perforating the inner shell in the transmission side improves sound insulation performance over a wide frequency band, and removes fluctuation of sound transmission loss with frequency at mid-frequencies in the absence of external flow. Both the incidence and azimuthal angles have nearly negligible effect on the sound transmission loss over the low and middle frequency range when perforating the inner shell. Width of the frequency band with continuous sound transmission loss can be tuned by the perforation ratio.

Nanostructuring the electronic conducting La0.8Sr0.2MnO3-δ cathode for high-performance in proton-conducting solid oxide fuel cells below 600°C

KAUST Repository

Da’ as, Eman Husni; Bi, Lei; Boulfrad, Samir; Traversa, Enrico

2017-01-01

Proton-conducting oxides offer a promising electrolyte solution for intermediate temperature solid oxide fuel cells (SOFCs) due to their high conductivity and low activation energy. However, the lower operation temperature leads to a reduced cathode activity and thus a poorer fuel cell performance. La0.8Sr0.2MnO3-δ (LSM) is the classical cathode material for high-temperature SOFCs, which lack features as a proper SOFC cathode material at intermediate temperatures. Despite this, we here successfully couple nanostructured LSM cathode with proton-conducting electrolytes to operate below 600°C with desirable SOFC performance. Inkjet printing allows depositing nanostructured particles of LSM on Y-doped BaZrO3(BZY) backbones as cathodes for proton-conducting SOFCs, which provides one of the highest power output for the BZY-based fuel cells below 600°C. This somehow changes the common knowledge that LSM can be applied as a SOFC cathode materials only at high temperatures (above 700°C).

Nanostructuring the electronic conducting La0.8Sr0.2MnO3-δ cathode for high-performance in proton-conducting solid oxide fuel cells below 600°C

KAUST Repository

Da’as, Eman Husni

2017-10-28

Proton-conducting oxides offer a promising electrolyte solution for intermediate temperature solid oxide fuel cells (SOFCs) due to their high conductivity and low activation energy. However, the lower operation temperature leads to a reduced cathode activity and thus a poorer fuel cell performance. La0.8Sr0.2MnO3-δ (LSM) is the classical cathode material for high-temperature SOFCs, which lack features as a proper SOFC cathode material at intermediate temperatures. Despite this, we here successfully couple nanostructured LSM cathode with proton-conducting electrolytes to operate below 600°C with desirable SOFC performance. Inkjet printing allows depositing nanostructured particles of LSM on Y-doped BaZrO3(BZY) backbones as cathodes for proton-conducting SOFCs, which provides one of the highest power output for the BZY-based fuel cells below 600°C. This somehow changes the common knowledge that LSM can be applied as a SOFC cathode materials only at high temperatures (above 700°C).

La(0.4)Ba(0.6)Fe(0.8)Zn(0.2)O(3-delta) as cathode in solid oxide fuel cells for simultaneous NO reduction and electricity generation.

Science.gov (United States)

Zhou, Renjie; Bu, Yunfei; Xu, Dandan; Zhong, Qin

2014-01-01

A perovskite-type oxide La(0.4)Ba(0.6)Fe(0.8)Zn(0.2)O(3-delta) (LBFZ) was investigated as the cathode material for simultaneous NO reduction and electricity generation in solid oxide fuel cells (SOFCs). The microstructure of LBFZ was demonstrated by X-ray diffraction and scanning electron microscopy. The results showed that a single cubic perovskite LBFZ was formed after calcined at 1100 degrees C. Meanwhile, the solid-state reaction between LBFZ and Ce(0.8)Sm(0.2)O(1.9) (SDC) at 900 degrees C was negligible. To measure the electrochemical properties, SOFC units were constructed with Sm(0.9)Sr(0.1)Cr(0.5)Fe(0.5)O3 as the anode, SDC as the electrolyte and LBFZ as the cathode. The maximum power density increased with the increasing NO concentration and temperature. The cell resistance is mainly due to the cathodic polarization resistance.

Differentiation of Acute Perforated from Non-Perforated Appendicitis: Usefulness of High-Resolution Ultrasonography

Energy Technology Data Exchange (ETDEWEB)

Choi, Gyu Chang [Dept. of Radiology, Gumi Hospital, Soonchunhyang University College of Medicine, Gumi (Korea, Republic of)

2011-07-15

To evaluate the usefulness of high-resolution ultrasonography (US) for the differentiation of acute perforated appendicitis from non-perforated appendicitis. The high-resolution US features in 96 patients (49 males, 47 females; mean age, 33.8 years; age range, 4-80 years) with pathologically proven acute appendicitis were evaluated. The following US findings were evaluated for differentiation of acute perforated appendicitis from non-perforated appendicitis: circumferential loss of the echogenic submucosal layer, periappendiceal fluid collection, disruption of the serosal layer, asymmetrical wall thickening, maximum overall diameter > 10.5 mm, and the presence of appendicoliths. The sensitivity and specificity of the US features in the diagnosis of acute perforated appendicitis were calculated. All of the US findings, except for appendicoliths, were significantly more common in the acute perforated appendicitis group (p < 0.001). The sensitivity of circumferential loss of the echogenic submucosal layer, periappendiceal fluid collection, disruption of the serosal layer, asymmetrical wall thickening, maximum overall diameter > 10.5 mm, and the presence of appendicoliths was 85.4, 73.2, 68.3, 70.7, 80.5, and 36.6%, respectively, while the specificity was 65.5, 89.1, 96.4, 98.2, 81.8, and 80.0%, respectively. High-resolution US was found to be useful for differentiating acute perforated appendicitis from non-perforated appendicitis.

In situ X-ray studies of film cathodes for solid oxide fuel cells

International Nuclear Information System (INIS)

Fuoss, Paul; Chang, Kee-Chul; You, Hoydoo

2013-01-01

Highlights: •Synchrotron X-rays are used to study in operando the structural and chemical changes of LSM and LSCF film cathodes during half-cell operations. •A-site and B-site cations actively segregate or desegregate on the changes of temperature, pO 2 , and electrochemical potential. •Chemical lattice expansions show that oxygen-cathode interface is the primary source of rate-limiting processes. •The surface and subsurface of the LSM and LSCF films have different oxidation-states due to vacancy concentration changes. •Liquid-phase infiltration and coarsening processes of cathode materials into porous YSZ electrolyte backbone were monitored by USAXS. -- Abstract: Synchrotron-based X-ray techniques have been used to study in situ the structural and chemical changes of film cathodes during half-cell operations. The X-ray techniques used include X-ray reflectivity (XR), total-reflection X-ray fluorescence (TXRF), high-resolution diffraction (HRD), ultra-small angle X-ray scattering (USAXS). The epitaxial thin film model cathodes for XR, TXRF, and HRD measurements are made by pulse laser deposition and porous film cathodes for USAX measurements are made by screen printing technique. The experimental results reviewed here include A-site and B-site segregations, lattice expansion, oxidation-state changes during cell operations and liquid-phase infiltration and coarsening of cathode to electrolyte backbone

High-performance electrodes for reduced temperature solid oxide fuel cells with doped lanthanum gallate electrolyte. Pt. 2. La(Sr)CoO{sub 3} cathode

Energy Technology Data Exchange (ETDEWEB)

Inagaki, Toru; Yoshida, Hiroyuki [The Kansai Electric Power, Hyogo (Japan); Miura, Kazuhiro [Kanden Kakou, Hyogo (Japan); Maric, Radenka; Ohara, Satoshi; Zhang, Xinge; Mukai, Kazuo; Fukui, Takehisa [Japan Fine Ceramics Center, Nagoya (Japan)

2000-03-01

The reduced temperature solid oxide fuel cell (SOFC) with 0.5 mm thick La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-{alpha}} (LSGM) electrolyte, La{sub 0.6}Sr{sub 0.4}CoO{sub 3-{delta}} (LSCo) cathode, and Ni-(CeO{sub 2}){sub 0.8}(SmO{sub 1.5}){sub 0.2} (SDC) cermet anode showed an excellent initial performance, and high maximum power density, 0.47 W/cm{sup 2}, at 800 C. The results were comparable to those for the conventional SOFC with yttria-stabilized zirconia (YSZ) electrolyte, La(Sr)MnO{sub 3}-YSZ cathode and Ni-YSZ cermet anode at 1000 C. Using an LSCo powder prepared by spray pyrolysis, and selecting appropriate sintering temperatures, the lowest cathodic polarization of about 25 mV at 300 mA/cm{sup 2} was measured for a cathode prepared by sintering at 1000 C. Life time cell test results, however, showed that the polarization of the LSCo cathode increased with operating time. From EPMA results, this behavior was considered to be related to the interdiffusion of the elements at the cathode/electrolyte interface. Calcination of LSCo powder could be a possible way to suppress this interdiffusion at the interface. (orig.)

Nontraumatic terminal ileal perforation

Directory of Open Access Journals (Sweden)

Wani Rauf A

2006-03-01

Full Text Available Abstract Background There is still confusion and controversy over the diagnosis and optimal surgical treatment of non traumatic terminal ileal perforation-a cause of obscure peritonitis. Methods This study was a prospective study aimed at evaluating the clinical profile, etiology and optimal surgical management of patients with nontraumatic terminal ileal perforation. Results There were 79 cases of nontraumatic terminal ileal perforation; the causes for perforation were enteric fever(62%, nonspecific inflammation(26%, obstruction(6%, tuberculosis(4% and radiation enteritis (1%. Simple closure of the perforation (49% and end to side ileotransverse anastomosis(42% were the mainstay of the surgical management. Conclusion Terminal ileal perforation should be suspected in all cases of peritonitis especially in developing countries and surgical treatment should be optimized taking various accounts like etiology, delay in surgery and operative findings into consideration to reduce the incidence of deadly complications like fecal fistula.

High Performance Fe-Co Based SOFC Cathodes

DEFF Research Database (Denmark)

Kammer Hansen, Kent; Hansen, Karin Vels; Mogensen, Mogens Bjerg

2010-01-01

With the aim of reducing the temperature of the solid oxide fuel cell (SOFC), a new high-performance perovskite cathode has been developed. An area-specific resistance (ASR) as low as 0.12 Ωcm2 at 600 °C was measured by electrochemical impedance spectroscopy (EIS) on symmetrical cells. The cathode...... is a composite between (Gd0.6Sr0.4)0.99Fe0.8Co0.2O3-δ (GSFC) and Ce0.9Gd0.1O1.95 (CGO10). Examination of the microstructure of the cathodes by scanning electron microscopy (SEM) revealed a possibility of further optimisation of the microstructure in order to increase the performance of the cathodes. It also...... seems that an adjustment of the sintering temperature will make a lowering of the ASR value possible. The cathodes were compatible with ceria-based electrolytes but reacted to some extent with zirconia-based electrolytes depending on the sintering temperature....

Solid oxide fuel cells fueled with reducible oxides

Science.gov (United States)

Chuang, Steven S.; Fan, Liang Shih

2018-01-09

A direct-electrochemical-oxidation fuel cell for generating electrical energy includes a cathode provided with an electrochemical-reduction catalyst that promotes formation of oxygen ions from an oxygen-containing source at the cathode, a solid-state reduced metal, a solid-state anode provided with an electrochemical-oxidation catalyst that promotes direct electrochemical oxidation of the solid-state reduced metal in the presence of the oxygen ions to produce electrical energy, and an electrolyte disposed to transmit the oxygen ions from the cathode to the solid-state anode. A method of operating a solid oxide fuel cell includes providing a direct-electrochemical-oxidation fuel cell comprising a solid-state reduced metal, oxidizing the solid-state reduced metal in the presence of oxygen ions through direct-electrochemical-oxidation to obtain a solid-state reducible metal oxide, and reducing the solid-state reducible metal oxide to obtain the solid-state reduced metal.

Using cathode spacers to minimize reactor size in air cathode microbial fuel cells

KAUST Repository

Yang, Qiao

2012-04-01

Scaling up microbial fuel cells (MFCs) will require more compact reactor designs. Spacers can be used to minimize the reactor size without adversely affecting performance. A single 1.5mm expanded plastic spacer (S1.5) produced a maximum power density (973±26mWm -2) that was similar to that of an MFC with the cathode exposed directly to air (no spacer). However, a very thin spacer (1.3mm) reduced power by 33%. Completely covering the air cathode with a solid plate did not eliminate power generation, indicating oxygen leakage into the reactor. The S1.5 spacer slightly increased columbic efficiencies (from 20% to 24%) as a result of reduced oxygen transfer into the system. Based on operating conditions (1000ς, CE=20%), it was estimated that 0.9Lh -1 of air would be needed for 1m 2 of cathode area suggesting active air flow may be needed for larger scale MFCs. © 2012 Elsevier Ltd.

Enhanced oxygen reduction activity and solid oxide fuel cell performance with a nanoparticles-loaded cathode.

Science.gov (United States)

Zhang, Xiaomin; Liu, Li; Zhao, Zhe; Tu, Baofeng; Ou, Dingrong; Cui, Daan; Wei, Xuming; Chen, Xiaobo; Cheng, Mojie

2015-03-11

Reluctant oxygen-reduction-reaction (ORR) activity has been a long-standing challenge limiting cell performance for solid oxide fuel cells (SOFCs) in both centralized and distributed power applications. We report here that this challenge has been tackled with coloading of (La,Sr)MnO3 (LSM) and Y2O3 stabilized zirconia (YSZ) nanoparticles within a porous YSZ framework. This design dramatically improves ORR activity, enhances fuel cell output (200-300% power improvement), and enables superior stability (no observed degradation within 500 h of operation) from 600 to 800 °C. The improved performance is attributed to the intimate contacts between nanoparticulate YSZ and LSM particles in the three-phase boundaries in the cathode.

Improving La0.6Sr0.4Co0.8Fe0.2O3-δ infiltrated solid oxide fuel cell cathode performance through precursor solution desiccation

Science.gov (United States)

Burye, Theodore E.; Nicholas, Jason D.

2015-02-01

Here, for the first time, the average size of solid oxide fuel cell (SOFC) electrode nano-particles was reduced through the chemical desiccation of infiltrated precursor nitrate solutions. Specifically, after firing at 700 °C, CaCl2-desiccated La0.6Sr0.4Co0.8Fe0.2O3-δ (LSCF) - Ce0.9Gd0.1O1.95 (GDC) cathodes contained LSCF infiltrate particles with an average size of 22 nm. This is in contrast to comparable, undesiccated LSCF-GDC cathodes which contained LSCF infiltrate particles with an average size of 48 nm. X-ray diffraction, scanning electron microscopy, and controlled atmosphere electrochemical impedance spectroscopy revealed that desiccation reduced the average infiltrate particle size without altering the infiltrate phase purity, the cathode concentration polarization resistance, or the cathode electronic resistance. Compared to undesiccated LSCF-GDC cathodes achieving polarization resistances of 0.10 Ωcm2 at 640 °C, comparable CaCl2-dessicated LSCF-GDC cathodes achieved 0.10 Ωcm2 at 575 °C. Mathematical modeling suggested that these performance improvements resulted solely from average infiltrate particle size reductions.

Reactive perforating collagenosis

Directory of Open Access Journals (Sweden)

Yadav Mukesh

2009-01-01

Full Text Available Reactive perforating collagenosis is a rare cutaneous disorder of unknown etiology. We hereby describe a case of acquired reactive perforating collagenosis in a patient of diabetes and chronic renal failure.

Combining rhinoplasty with septal perforation repair.

Science.gov (United States)

Foda, Hossam M T; Magdy, Emad A

2006-11-01

A combined septal perforation repair and rhinoplasty was performed in 80 patients presenting with septal perforations (size 1 to 5 cm) and external nasal deformities. The external rhinoplasty approach was used for all cases and the perforation was repaired using bilateral intranasal mucosal advancement flaps with a connective tissue interposition graft in between. Complete closure of the perforation was achieved in 90% of perforations of size up to 3.5 cm and in only 70% of perforations that were larger than 3.5 cm. Cosmetically, 95% were very satisfied with their aesthetic result. The external rhinoplasty approach proved to be very helpful in the process of septal perforation repair especially in large and posteriorly located perforations and in cases where the caudal septal cartilage was previously resected. Our results show that septal perforation repair can be safely combined with rhinoplasty and that some of the routine rhinoplasty maneuvers, such as medial osteotomies and dorsal lowering, could even facilitate the process of septal perforation repair.

Assessment of the cathode contribution to the degradation of anode-supported solid oxide fuel cells

DEFF Research Database (Denmark)

Hagen, Anke; Liu, Yi-Lin; Barfod, Rasmus

2008-01-01

The degradation of anode-supported cells was studied over 1500 h as a function of cell polarization either in air or oxygen on the cathode side. Based on impedance analysis, contributions of the anode and cathode to the increase of total resistance were assigned. Accordingly, the degradation rates...... of the cathode were strongly dependent on the pO(2). Microstructural analysis of the cathode/electrolyte interface carried out after removal of the cathode showed craters on the electrolyte surface where the lanthanum strontium manganite (LSM) particles had been located. The changes of shape and size...... of these craters observed after testing correlated with the cell voltage degradation rates. The results can be interpreted in terms of element redistribution at the cathode/electrolyte interface and formation of foreign phases giving rise to a weakening of local contact points of the LSM cathode and yttria...

Spectrum of Perforation Peritonitis

Science.gov (United States)

Chakma, Sujit M.; Singh, Rahul L.; Parmekar, Mahadev V.; Singh, K.H. Gojen; Kapa, Buru; Sharatchandra, K.H.; Longkumer, Amenla T.; Rudrappa, Santhosh

2013-01-01

Introduction: Perforation peritonitis mostly results from the perforation of a diseased viscus. Other causes of perforation include abdominal trauma, ingestion of sharp foreign body and iatrogenic perforation. The diagnosis is mainly based on clinical grounds. Plain abdominal X-rays (erect) may reveal dilated and oedematous intestines with pneumoperitoneum. Ultrasound and CT scan may diagnose up to 72% and 82% of perforation respectively. The present study was carried out to study various etiological factors, modes of clinical presentation, morbidity and mortality patterns of perforation peritonitis presented in the RIMS hospital, Imphal, India. Material and Methods: The study was conducted from September 2010 to August 2012 on 490 cases of perforation peritonitis admitted and treated in the Department of Surgery. Initial diagnosis was made on the basis of detailed history, clinical examination and presence of pneumoperitoneum on erect abdominal X-ray. Results: A total of 490 patients of perforation peritonitis were included in the study, with mean age of 48.28 years. 54.29% patients were below 50 years and 45.71% patients were above 50 years. There were 54.29% male patients and 45.71% female patients. Only 30% patients presented within 24 hours of onset of symptoms, 31.43% patients presented between 24 to 72 hours and 38.57% patients presented 72 hours after the onset of symptoms. Mean duration of presentation was 54.7 hours. Overall 469 patients were treated surgically and 21 patients were managed conservatively. Overall morbidity and mortality recorded in this study were 52.24% and 10% respectively. PMID:24392388

Perforations during contrast enema

International Nuclear Information System (INIS)

Vogel, H.; Steinkamp, U.; Grabbe, E.; Allgemeines Krankenhaus Ochsenzoll, Hamburg

1983-01-01

During contrast enema, perforation into the retroperitoneal space can be differentiated from perforation into the peritoneum and perforation into the intestinal wall associated with formation of barium granulomas or submucosal spreading of the contrast medium. Other special forms are perforation with contrast medium embolism of diverticula; of the processus vermiformis; penetration of contrast medium into fistulous systems and from the operated areas. Risk factors are: balloon catheter, intestinal tubes with a hard tip, preternatural anus, excessive enema pressure, contrast medium additions, preceding manipulations, intestinal diseases, advanced age and delegation of manipulations to assistants and unskilled staff. Children are particularly at risk. (orig.) [de

Effects of grain boundaries at the electrolyte/cathode interfaces on oxygen reduction reaction kinetics of solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Choi, Min Gi; Koo, Ja Yang; Ahn, Min Woo; Lee, Won Young [Dept. of Mechanical Engineering, Sungkyunkwan University, Suwon (Korea, Republic of)

2017-04-15

We systematically investigated the effects of grain boundaries (GBs) at the electrolyte/cathode interface of two conventional electrolyte materials, i.e., yttria-stabilized zirconia (YSZ) and gadolinia-doped ceria (GDC). We deposited additional layers by pulsed laser deposition to control the GB density on top of the polycrystalline substrates, obtaining significant improvements in peak power density (two-fold for YSZ and three-fold for GDC). The enhanced performance at high GB density in the additional layer could be ascribed to the accumulation of oxygen vacancies, which are known to be more active sites for oxygen reduction reactions (ORR) than grain cores. GDC exhibited a higher enhancement than YSZ, due to the easier formation, and thus higher concentration, of oxygen vacancies for ORR. The strong relation between the concentration of oxygen vacancies and the surface exchange characteristics substantiated the role of GBs at electrolyte/cathode interfaces on ORR kinetics, providing new design parameters for highly performing solid oxide fuel cells.

The freestyle pedicle perforator flap

DEFF Research Database (Denmark)

Gunnarsson, Gudjon Leifur; Jackson, Ian T; Westvik, Tormod S

2015-01-01

BACKGROUND: Perforating vessels are a consistent anatomical finding and well described in the current literature. Any skin flap can be raised on a subcutaneous pedicle as long as it contains at least one supplying perforator. Perforator flaps have been interlinked with microsurgery and generally...... not widely performed by the general plastic surgeons. The aim of this paper is to present the simplicity of pedicled perforator flap reconstruction of moderate-sized defects of the extremities and torso. METHODS: We retrospectively reviewed the charts of 34 patients reconstructed using 34 freestyle pedicled...... perforator flaps for moderate-sized defects of the truncus and extremities. We registered indications, flap size and localization, success rate, and complications. Most importantly, we describe a simple approach to the design of freestyle pedicled perforator flaps and elaborate on technical aspects...

Solid oxide fuel cell cathode with oxygen-reducing layer

Science.gov (United States)

Surdoval, Wayne A.; Berry, David A.; Shultz, Travis

2018-04-03

The disclosure provides a SOFC comprised of an electrolyte, anode, and cathode, where the cathode comprises an MIEC and an oxygen-reducing layer. The oxygen-reducing layer is in contact with the MIEC, and the MIEC is generally between and separating the oxygen-reducing layer and the electrolyte. The oxygen-reducing layer is comprised of single element oxides, single element carbonates, or mixtures thereof, and has a thickness of less than about 30 nm. In a particular embodiment, the thickness is less than 5 nm. In another embodiment, the thickness is about 3 monolayers or less. The oxygen-reducing layer may be a continuous film or a discontinuous film with various coverage ratios. The oxygen-reducing layer at the thicknesses described may be generated on the MIEC surface using means known in the art such as, for example, ALD processes.

Thin Solid Oxide Cell

DEFF Research Database (Denmark)

2010-01-01

The present invention relates to a thin and in principle unsupported solid oxide cell, comprising at least a porous anode layer, an electrolyte layer and a porous cathode layer, wherein the anode layer and the cathode layer comprise an electrolyte material, at least one metal and a catalyst...... material, and wherein the overall thickness of the thin reversible cell is about 150 [mu]m or less, and to a method for producing same. The present invention also relates to a thin and in principle unsupported solid oxide cell, comprising at least a porous anode layer, an electrolyte layer and a porous...... cathode layer, wherein the anode layer and the cathode layer comprise an electrolyte material and a catalyst material, wherein the electrolyte material is doper zirconia, and wherein the overall thickness of the thin reversible cell is about 150 [mu]m or less, and to a method for producing same...

Impedance of SOFC electrodes: A review and a comprehensive case study on the impedance of LSM:YSZ cathodes

DEFF Research Database (Denmark)

Nielsen, Jimmi; Hjelm, Johan

2014-01-01

It was shown through a comprehensive impedance spectroscopy study that the impedance of the classic composite LSM:YSZ (lanthanum strontium manganite and yttria stabilized zirconia) solid oxide fuel cell (SOFC) cathode can be described well with porous electrode theory. Furthermore, it was illustr......It was shown through a comprehensive impedance spectroscopy study that the impedance of the classic composite LSM:YSZ (lanthanum strontium manganite and yttria stabilized zirconia) solid oxide fuel cell (SOFC) cathode can be described well with porous electrode theory. Furthermore......, it was illustrated through a literature review on SOFC electrodes that porous electrode theory not only describes the classic LSM:YSZ SOFC cathode well, but SOFC electrodes in general. The extensive impedance spectroscopy study of LSM:YSZ cathodes consisted of measurements on cathodes with three different sintering...... temperatures and hence different microstructures and varying degrees of LSM/YSZ solid state interactions. LSM based composite cathodes, where YSZ was replaced with CGO was also studied in order to acquire further knowledge on the chemical compatibility between LSM and YSZ. All impedance measurements were...

Multiscale Transient and Steady-State Study of the Influence of Microstructure Degradation and Chromium Oxide Poisoning on Solid Oxide Fuel Cell Cathode Performance

Science.gov (United States)

Li, Guanchen; von Spakovsky, Michael R.; Shen, Fengyu; Lu, Kathy

2018-01-01

Oxygen reduction in a solid oxide fuel cell cathode involves a nonequilibrium process of coupled mass and heat diffusion and electrochemical and chemical reactions. These phenomena occur at multiple temporal and spatial scales, making the modeling, especially in the transient regime, very difficult. Nonetheless, multiscale models are needed to improve the understanding of oxygen reduction and guide cathode design. Of particular importance for long-term operation are microstructure degradation and chromium oxide poisoning both of which degrade cathode performance. Existing methods are phenomenological or empirical in nature and their application limited to the continuum realm with quantum effects not captured. In contrast, steepest-entropy-ascent quantum thermodynamics can be used to model nonequilibrium processes (even those far-from equilibrium) at all scales. The nonequilibrium relaxation is characterized by entropy generation, which can unify coupled phenomena into one framework to model transient and steady behavior. The results reveal the effects on performance of the different timescales of the varied phenomena involved and their coupling. Results are included here for the effects of chromium oxide concentrations on cathode output as is a parametric study of the effects of interconnect-three-phase-boundary length, oxygen mean free path, and adsorption site effectiveness. A qualitative comparison with experimental results is made.

Equivalent material properties of perforated plate with triangular or square penetration pattern for dynamic analysis

International Nuclear Information System (INIS)

Jhung, Myung Jo; Jo, Jong Chull

2006-01-01

For a perforated plate, it is challenging to develop a finite element model due to the necessity of the fine meshing of the plate, especially if it is submerged in fluid. This necessitates the use of a solid plate with equivalent material properties. Unfortunately, the effective elastic constants suggested by the ASME code are deemed not valid for a model analysis. Therefore, in this study the equivalent material properties of a perforated plate are suggested by performing several finite element analyses with respect to the ligament efficiencies

Praseodymium Cuprate Thin Film Cathodes for Intermediate Temperature Solid Oxide Fuel Cells: Roles of Doping, Orientation, and Crystal Structure.

Science.gov (United States)

Mukherjee, Kunal; Hayamizu, Yoshiaki; Kim, Chang Sub; Kolchina, Liudmila M; Mazo, Galina N; Istomin, Sergey Ya; Bishop, Sean R; Tuller, Harry L

2016-12-21

Highly textured thin films of undoped, Ce-doped, and Sr-doped Pr 2 CuO 4 were synthesized on single crystal YSZ substrates using pulsed laser deposition to investigate their area-specific resistance (ASR) as cathodes in solid-oxide fuel cells (SOFCs). The effects of T' and T* crystal structures, donor and acceptor doping, and a-axis and c-axis orientation on ASR were systematically studied using electrochemical impedance spectroscopy on half cells. The addition of both Ce and Sr dopants resulted in improvements in ASR in c-axis oriented films, as did the T* crystal structure with the a-axis orientation. Pr 1.6 Sr 0.4 CuO 4 is identified as a potential cathode material with nearly an order of magnitude faster oxygen reduction reaction kinetics at 600 °C compared to thin films of the commonly studied cathode material La 0.6 Sr 0.4 Co 0.8 Fe 0.2 O 3-δ . Orientation control of the cuprate films on YSZ was achieved using seed layers, and the anisotropy in the ASR was found to be less than an order of magnitude. The rare-earth doped cuprate was found to be a versatile system for study of relationships between bulk properties and the oxygen reduction reaction, critical for improving SOFC performance.

Electrode Design for Low Temperature Direct-Hydrocarbon Solid Oxide Fuel Cells

Science.gov (United States)

Chen, Fanglin (Inventor); Zhao, Fei (Inventor); Liu, Qiang (Inventor)

2015-01-01

In certain embodiments of the present disclosure, a solid oxide fuel cell is described. The solid oxide fuel cell includes a hierarchically porous cathode support having an impregnated cobaltite cathode deposited thereon, an electrolyte, and an anode support. The anode support includes hydrocarbon oxidation catalyst deposited thereon, wherein the cathode support, electrolyte, and anode support are joined together and wherein the solid oxide fuel cell operates a temperature of 600.degree. C. or less.

Electrode design for low temperature direct-hydrocarbon solid oxide fuel cells

Science.gov (United States)

Chen, Fanglin; Zhao, Fei; Liu, Qiang

2015-10-06

In certain embodiments of the present disclosure, a solid oxide fuel cell is described. The solid oxide fuel cell includes a hierarchically porous cathode support having an impregnated cobaltite cathode deposited thereon, an electrolyte, and an anode support. The anode support includes hydrocarbon oxidation catalyst deposited thereon, wherein the cathode support, electrolyte, and anode support are joined together and wherein the solid oxide fuel cell operates a temperature of 600.degree. C. or less.

CT in acute perforated sigmoid diverticulitis

International Nuclear Information System (INIS)

Lohrmann, Christian; Ghanem, Nadir; Pache, Gregor; Makowiec, Frank; Kotter, Elmar; Langer, Mathias

2005-01-01

Background: To assess the value of computed tomography (CT) in patients with acute perforated sigmoid diverticulitis in correlation with the Hinchey classification of perforated diverticular disease. Methods: Thirty patients with acute perforated sigmoid diverticulitis underwent computed tomography prior to surgery. Computed tomography scans were compared with the surgical and histopathological reports, utilizing the Hinchey classification. Results: In 28 of the 30 (93%) patients examined, the Hinchey stage was correctly determined by means of computed tomography. One patient with Hinchey stage IV was falsely classified as Hinchey stage III, and one patient with Hinchey stage III as Hinchey stage II. Computed tomography revealed 12 out of 14 (86%) patients with perforation sites and 3 out of 3 (100%) patients with contained perforation. In one of 17 (6%) patients with surgically or histopathologically proven perforation or contained perforation, a bowel wall discontinuity was revealed by computed tomography. In 6 of the 17 (35%) patients with surgical or histopathological perforation or contained perforation, extraluminal contrast material was detected by computed tomography. Conclusions: Computed tomography is a valuable imaging tool for determining the degree of acute perforated sigmoid diverticulitis, by means of which patients can be stratified according to the severity of the disease; furthermore, this tool is of assistance in surgical planning

Layered perovskite PrBa0.5Sr0.5CoCuO5+δ as a cathode for intermediate-temperature solid oxide fuel cells

International Nuclear Information System (INIS)

Wang, Biao; Long, Guohui; Ji, Yuan; Pang, Mingjun; Meng, Xiangwei

2014-01-01

Highlights: • A single-phase layered-perovskite PrBa 0.5 Sr 0.5 CoCuO 5+δ (PBSCCu) is prepared by the EDTA–citrate complexing method. • PBSCCu cathode has a good chemical compatible with GDC electrolyte. • Partial substitution of Cu for Co can efficiently lower the thermal expansion coefficient. • Performances of PrBa 0.5 Sr 0.5 CoCuO 5+δ cathode based on Gd 0.1 Ce 0.9 O 1.95 electrolyte is reported firstly. - Abstract: Layered perovskite PrBa 0.5 Sr 0.5 CoCuO 5+δ (PBSCCo) oxide is synthesized by EDTA–citrate complexing method and investigated as a novel cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). X-ray diffraction results show that PBSCCo is chemical compatible with Gd 0.1 Ce 0.9 O 1.95 (GDC) electrolyte below 950 °C. The thermal expansion coefficient of PBSCCo is 17.58 × 10 −6 K −1 between 30 °C and 900 °C. The maximum electrical conductivity of PBSCCo is 483 S cm −1 at 325 °C. The polarization resistance of PBSCCo cathode on GDC electrolyte is as low as 0.06 Ω cm 2 at 800 °C. The maximum power density of the electrolyte-supported single cell with PBSCCo cathode achieves 521 mW cm −2 at 800 °C. Preliminary results indicate that PBSCCo is a potential cathode material for application in IT-SOFCs

High-Resolution Ultrasonography (US) of Appendiceal Specimens: Differentiation of Acute Non-perforated Appendicitis from Perforated Appendicitis

Energy Technology Data Exchange (ETDEWEB)

Choi, Gyo Chang; Kim, Suk; Im, Han Hyeok; Lee, Sang Jin; Yang, Seung Boo; Lee, Seung Woo; Kim, Il Young [Soonchunhyang University Gumi Hospital, Gumi (Korea, Republic of); Lee, Hae Kyung [Soonchunhyang University Bucheon Hospital, Bucheon (Korea, Republic of); Kwon, Kui Hyang; Shin, Hyung Chul [Soonchunhyang University, College of Medicine, Seoul (Korea, Republic of)

2007-09-15

To analyze surgical specimens from patients with acute non-perforated and perforated appendicitis using high-resolution ultrasonography (US), and to correlate the US features with the pathologic findings. One hundred and six surgical appendix specimens obtained from patients with suspected acute appendicitis were evaluated. The following US features were evaluated for differentiating acute non-perforated appendicitis from perforated appendicitis: circumferential loss of the echogenic submucosal layer, disruption of the serosal layer, asymmetrical wall thickening, the sum of opposing walls {>=} 9 mm and the presence of appendicoliths. The sensitivity and specificity of the US findings for diagnosing perforated appendicitis were determined. All US features were detected significantly more often in the perforated appendicitis group of specimens. The disruption of the serosal layer was the most significant independent predictor of perforation (p < .001). The sensitivity for circumferential loss of the echogenic submucosal layer, disruption of the serosal layer, asymmetrical wall thickening, wall thickness {>=} 9 mm, and the presence of appendicoliths individually was 84.6%, 69.2%, 61.5%, 73.1% and 46.2%, respectively. The specificity for all of these findings was 86.3%, 98.7%, 95.0%, 85.0% and 85.0%, respectively. High-resolution US of appendiceal specimens was very useful for differentiating acute non-perforated from perforated appendicitis

Investigation of novel solid oxide fuel cell cathodes based on impregnation of SrTixFe1-xO3-δ into ceria-based backbones

DEFF Research Database (Denmark)

Brinch-Larsen, Mathias; Søgaard, Martin; Hjelm, Johan

2013-01-01

Solid oxide fuel cell (SOFC) cathodes were prepared by impregnating the nitrates corresponding to SrTixFe1-xO3-δ (STF), x= 0; 0.1; 0.2; 0.3; 0.4 and 0.5, into a porous backbone of Ce 0.9Gd0.1O2-δ (CGO). STF was chosen as very high oxygen surface exchange rate, high ionic conductivity and electroc......Solid oxide fuel cell (SOFC) cathodes were prepared by impregnating the nitrates corresponding to SrTixFe1-xO3-δ (STF), x= 0; 0.1; 0.2; 0.3; 0.4 and 0.5, into a porous backbone of Ce 0.9Gd0.1O2-δ (CGO). STF was chosen as very high oxygen surface exchange rate, high ionic conductivity...... backbone. All prepared electrodes were characterized as symmetric cells using impedance spectroscopy. Within the investigated series the infiltrate with x = 0.1 (STF10) showed the best performance with an area specific resistance (ASR) of ASR ≈ 6.4 Ω cm2 (STF10) at 600°C in air. The relatively poor...

Cermet cathodes for strontium and magnesium-doped LaGaO3-based solid oxide fuel cells

International Nuclear Information System (INIS)

Datta, Pradyot; Bronin, D.I.; Majewski, P.; Aldinger, F.

2009-01-01

To check the suitability of La 0.9 Sr 0.1 Ga 0.85 Mg 0.15 O 3-δ -Ag cermets as cathode material for solid oxide fuel cell (SOFC) with Sr- and Mg-doped LaGaO 3 electrolyte a series of cermets with different Ag contents were prepared by conventional sintering process. The chemical compatibility between La 0.9 Sr 0.1 Ga 0.85 Mg 0.15 O 3-δ (LSGM) and Ag was investigated by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Thermal expansion coefficient of the cermets was measured as a function of Ag content and was found to increase with increasing metallic content. Oxygen adsorption at the surface of the cermets could be detected but no reaction or solid solubility between LSGM and Ag was found. It was noticed that a minimum of 30 wt.% Ag is needed to form a cermet with percolating network. From impedance spectroscopy measurement activation energy for the polarization conductance was found to be around 110 kJ mol -1

Management of biliary perforation in children

Directory of Open Access Journals (Sweden)

Mirza Bilal

2010-01-01

Full Text Available Background: To study the aetiology, management and outcome of biliary perforations in paediatric age group. Patients and Methods: In a retrospective study, the records of patients presented with biliary peritonitis due to biliary perforations, managed from March 2006 to July 2009, are reviewed. Results: Eight male patients with biliary peritonitis due to biliary perforation were managed. These patients were divided in two groups, A and B. Group A, (n = 3 patients, had common bile duct (CBD perforation, and Group B (n=5 patients had gallbladder perforation. The presenting features were abdominal pain, fever, abdominal distension, vomiting, constipation, jaundice and signs of peritonism. The management of CBD perforations in Group A was by draining the site of perforation and biliary diversion (tube cholecystostomy. In Group B, the gallbladder perforations were managed by tube cholecystostomy in four patients and cholecystectomy in one patient, however, one patient had to be re-explored and cholecystectomy performed due to complete necrosis of gall bladder. There was no mortality in our series. All patients were asymptomatic on regular follow-up. Conclusion: Early optimal management of biliary perforations remarkably improved the very high mortality and morbidity that characterised this condition in the past.

Solid Oxide Fuel Cell

DEFF Research Database (Denmark)

2010-01-01

The solid oxide fuel cell comprising a metallic support material, an active anode layer consisting of a good hydrocarbon cracking catalyst, an electrolyte layer, an active cathode layer, and a transition layer consisting of preferably a mixture of LSM and a ferrite to the cathode current collector...

Passivation-free solid state battery

Science.gov (United States)

Abraham, Kuzhikalail M.; Peramunage, Dharmasena

1998-01-01

This invention pertains to passivation-free solid-state rechargeable batteries composed of Li.sub.4 Ti.sub.5 O.sub.12 anode, a solid polymer electrolyte and a high voltage cathode. The solid polymer electrolyte comprises a polymer host, such as polyacrylonitrile, poly(vinyl chloride), poly(vinyl sulfone), and poly(vinylidene fluoride), plasticized by a solution of a Li salt in an organic solvent. The high voltage cathode includes LiMn.sub.2 O.sub.4, LiCoO.sub.2, LiNiO.sub.2 and LiV.sub.2 O.sub.5 and their derivatives.

Early Management Experience of Perforation after ERCP

Directory of Open Access Journals (Sweden)

Guohua Li

2012-01-01

Full Text Available Background and Aim. Perforation after endoscopic retrograde cholangiopancreatography (ERCP is a rare complication, but it is associated with significant mortality. This study evaluated the early management experience of these perforations. Patients and Methods. Between November 2003 and December 2011, a total of 8504 ERCPs were performed at our regional endoscopy center. Sixteen perforations (0.45% were identified and retrospectively reviewed. Results. Nine of these 16 patients with perforations were periampullary, 3 duodenal, 1 gastric fundus, and 3 patients had a perforation of an afferent limb of a Billroth II anastomosis. All patients with perforations were recognized during ERCP by X-ray and managed immediately. One patient with duodenal perforation and three patients with afferent limb perforation received surgery, others received medical conservative treatment which included suturing lesion, endoscopic nasobiliary drainage (ENBD, endoscopic retrograde pancreatic duct drainage (ERPD, gastrointestinal decompression, fasting, broad-spectrum antibiotics, and so on. All patients with perforation recovered successfully. Conclusions. We found that: (1 the diagnosis of perforation during ERCP may be easy, but you must pay attention to it. (2 Most retroperitoneal perforations can recover with only medical conservative treatment in early phase. (3 Most peritoneal perforations need surgery unless you can close the lesion up under endoscopy in early phase.

The Perforation-Operation time Interval; An Important Mortality Indicator in Peptic Ulcer Perforation.

Science.gov (United States)

Surapaneni, Sushama; S, Rajkumar; Reddy A, Vijaya Bhaskar

2013-05-01

To find out the significance of the Perforation-Operation Interval (POI) with respect to an early prognosis, in patients with peritonitis which is caused by peptic ulcer perforation. Case series. Place and Duration of the Study: Department of General Surgery, Konaseema Institute of Medical Sciences and RF Amalapuram, Andhra Pradesh, India from 2008-2011. This study included 150 patients with generalized peritonitis, who were diagnosed to have Perforated Peptic Ulcers (PPUs). The diagnosis of the PPUs was established on the basis of the history , the clinical examination and the radiological findings. The perforation-operation interval was calculated from the time of onset of the symptoms like severe abdominal pain or vomiting till the time the patient was operated. Out of the 150 patients 134 were males and 16 were females, with a male : female ratio of 9:1. Their ages ranged between 25-70 years. Out of the 150 patients, 65 patients (43.3%) presented within 24 hours of the onset of severe abdominal pain (Group A), 27 patients (18%) presented between 24-48 hours of the onset of severe abdominal pain (Group B) and 58 patients (38.6%) presented after 48 hours. There was no mortality in Group A and the morbidity was more in Group B and Group C. There were 15 deaths in Group C. The problem of peptic ulcer perforation with its complication, can be decreased by decreasing the perforation -operation time interval, which as per our study, appeared to be the single most important mortality and morbidity indicator in peptic ulcer perforation.

A novel cobalt-free layered GdBaFe{sub 2}O{sub 5+{delta}} cathode for proton conducting solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Ding, Hanping; Xue, Xingjian [Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208 (United States)

2010-07-01

While cobalt-containing perovskite-type cathode materials facilitate the activation of oxygen reduction, they also suffer from problems like poor chemical stability in CO{sub 2} and high thermal expansion coefficients. In this research, a cobalt-free layered GdBaFe{sub 2}O{sub 5+{delta}} (GBF) perovskite was developed as a cathode material for protonic ceramic membrane fuel cells (PCMFCs) based on proton conducting electrolyte of stable BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.2}O{sub 3-{delta}} (BZCY7). The button cells of Ni-BZCY7 vertical stroke BZCY7 vertical stroke GBF were fabricated and characterized using complex impedance technique from 600 to 700 C. An open-circuit potential of 1.007 V, maximum power density of 417 mW cm{sup -2}, and a low electrode polarization resistance of 0.18 {omega} cm{sup 2} were achieved at 700 C. The results indicate that layered GBF perovskite is a good candidate for cobalt-free cathode material, while the developed Ni-BZCY7 vertical stroke BZCY7 vertical stroke GBF cell is a promising functional material system for solid oxide fuel cells. (author)

Fabrication and electrochemical properties of cathode-supported solid oxide fuel cells via slurry spin coating

International Nuclear Information System (INIS)

Chen Min; Luo Jingli; Chuang, Karl T.; Sanger, Alan R.

2012-01-01

Highlights: ► LSM cathode-supported cell prepared by slurry spin coating. ► Optimizing porosity in CFL resulting in power density of 0.58 W cm −2 at 850 °C. ► Activation polarization govern the impedance arcs measured under the OCV condition. ► Concentration polarization can induce the change of activation polarization. ► Four kinds of polarizations of our cells are separated and investigated. - Abstract: A cathode-supported SOFC consisting of LSM (La 0.8 Sr 0.2 MnO 3−δ ) cathode supporter, LSM–Sm 0.2 Ce 0.8 O 2−δ (SDC) cathode functional layer (CFL), yttria stabilized zirconia (YSZ)/SDC bi-layered electrolyte and Ni-YSZ anode layer was fabricated by a slurry spin coating technique. The influence of the porosity in both the CFL and cathode supporter on the electrochemical properties of the cells has been investigated. It was found that properly controlling the porosity in the CFL would improve the performance of the cells using O 2 in the cathode side (O 2 -cells), with a maximum power density (MPD) value achieving as high as 0.58 W cm −2 at 850 °C. However, this improvement is not so evident for the cells using air in the cathode side (air-cells). When increasing the porosity in the cathode-supporter, a significant increase of the power density for the air cells due to the decreasing R conc,c (cathode concentration polarization to the cell resistance) can be ascertained. In terms of our analysis on various electrochemical parameters, the R act (activation polarization to the cell resistance) is assumed to be mainly responsible for the impedance arcs measured under the OCV condition, with a negligible R conc,c value being able to be detected in our impedances. In this case, a significant decreasing size of the impedance arcs due to the increasing porosity in the cathode supporter would correspond to a decrease of the R act values, which was proved to be induced by the decreasing R conc,c .

A highly active hybrid catalyst modified (La0.60Sr0.40)0.95Co0.20Fe0.80O3-δ cathode for proton conducting solid oxide fuel cells

Science.gov (United States)

Lei, Libin; Tao, Zetian; Hong, Tao; Wang, Xiaoming; Chen, Fanglin

2018-06-01

The sluggish reaction kinetics in the cathode usually leads to considerable cathode polarization resistance, hindering the development of proton conducting solid oxide fuel cells (H-SOFCs) operated at intermediate temperatures (400-650 °C). To address this problem, for the first time, a novel hybrid catalyst consisting of PrNi0.5Mn0.5O3 and PrOx is impregnated in the (La0.60Sr0.40)0.95Co0.20Fe0.80O3-δ (LSCF) cathode of H-SOFCs, resulting in significant enhancement of the cathode reaction kinetics. Single cells with impregnated LSCF cathode and BaZr0.8Y0.2O3 (BZY) electrolyte yield a maximum power density (MPD) of 0.198 W cm-2 at 600 °C, more than doubled of that with blank LSCF cathode (0.083 W cm-2). ECR and EIS studies reveal that the hybrid catalyst can substantially accelerate the oxygen-ion transfer and oxygen dissociation-absorption processes in the cathode, resulting in significantly lower polarization resistance and higher MPD. In addition, the hybrid catalyst possesses good chemical and microstructural stability at 600 °C. Consequently, the single cells with impregnated LSCF cathode show excellent durability. This study shows that the impregnation of this novel hybrid catalyst in the cathode could be a promising approach to improve the performance and stability of H-SOFCs.

Semi-solid electrodes having high rate capability

Energy Technology Data Exchange (ETDEWEB)

Chiang, Yet-Ming; Duduta, Mihai; Holman, Richard; Limthongkul, Pimpa; Tan, Taison

2017-11-28

Embodiments described herein relate generally to electrochemical cells having high rate capability, and more particularly to devices, systems and methods of producing high capacity and high rate capability batteries having relatively thick semi-solid electrodes. In some embodiments, an electrochemical cell includes an anode, a semi-solid cathode that includes a suspension of an active material and a conductive material in a liquid electrolyte, and an ion permeable membrane disposed between the anode and the cathode. The semi-solid cathode has a thickness in the range of about 250 .mu.m-2,500 .mu.m, and the electrochemical cell has an area specific capacity of at least 5 mAh/cm.sup.2 at a C-rate of C/2.

Unraveling the Role of Transport, Electrocatalysis, and Surface Science in the Solid Oxide Fuel Cell Cathode Oxygen Reduction Reaction

Energy Technology Data Exchange (ETDEWEB)

Gopalan, Srikanth [Boston Univ., MA (United States)

2017-04-06

This final report for project FE0009656 covers the period from 10/01/2012 to 09/30/2015 and covers research accomplishments on the effects of carbon dioxide on the surface composition and structure of cathode materials for solid oxide fuel cells (SOFCs), specifically La1-xSrxFeyCo1- yO3-δ (LSCF). Epitaxially deposited thin films of LSCF on various single-crystal substrates have revealed the selective segregation of strontium to the surface thereby resulting in a surface enrichment of strontium. The near surface compositional profile in the films have been measured using total x-ray fluorescence (TXRF), and show that the kinetics of strontium segregation are higher at higher partial pressures of carbon dioxide. Once the strontium segregates to the surface, it leads to the formation of precipitates of SrO which convert to SrCO3 in the presence of even modest concentrations of carbon dioxide in the atmosphere. This has important implications for the performance of SOFCs which is discussed in this report. These experimental observations have also been verified by Density Functional Theory calculations (DFT) which predict the conditions under which SrO and SrCO3 can occur in LSCF. Furthermore, a few cathode compositions which have received attention in the literature as alternatives to LSCF cathodes have been studied in this work and shown to be thermodynamically unstable under the operating conditions of the SOFCs.

Modeling and Predicting the Electrical Conductivity of Composite Cathode for Solid Oxide Fuel Cell by Using Support Vector Regression

Science.gov (United States)

Tang, J. L.; Cai, C. Z.; Xiao, T. T.; Huang, S. J.

2012-07-01

The electrical conductivity of solid oxide fuel cell (SOFC) cathode is one of the most important indices affecting the efficiency of SOFC. In order to improve the performance of fuel cell system, it is advantageous to have accurate model with which one can predict the electrical conductivity. In this paper, a model utilizing support vector regression (SVR) approach combined with particle swarm optimization (PSO) algorithm for its parameter optimization was established to modeling and predicting the electrical conductivity of Ba0.5Sr0.5Co0.8Fe0.2 O3-δ-xSm0.5Sr0.5CoO3-δ (BSCF-xSSC) composite cathode under two influence factors, including operating temperature (T) and SSC content (x) in BSCF-xSSC composite cathode. The leave-one-out cross validation (LOOCV) test result by SVR strongly supports that the generalization ability of SVR model is high enough. The absolute percentage error (APE) of 27 samples does not exceed 0.05%. The mean absolute percentage error (MAPE) of all 30 samples is only 0.09% and the correlation coefficient (R2) as high as 0.999. This investigation suggests that the hybrid PSO-SVR approach may be not only a promising and practical methodology to simulate the properties of fuel cell system, but also a powerful tool to be used for optimal designing or controlling the operating process of a SOFC system.

Kinetics of oxygen reduction in perovskite cathodes for solid oxide fuel cells: A combined modeling and experimental approach

Science.gov (United States)

Miara, Lincoln James

Solid oxide fuel cells (SOFCs) have the potential to replace conventional stationary power generation technologies; however, there are major obstacles to commercialization, the most problematic of which is poor cathode performance. Commercialization of SOFCs will follow when the mechanisms occurring at the cathode are more thoroughly understood and adapted for market use. The catalytic reduction of oxygen occurring in SOFC cathodes consists of many elementary steps such as gas phase diffusion, chemical and/or electrochemical reactions which lead to the adsorption and dissociation of molecular oxygen onto the cathode surface, mass transport of oxygen species along the surface and/or through the bulk of the cathode, and full reduction and incorporation of the oxygen at the cathode/electrolyte two or three phase boundary. Electrochemical impedance spectroscopy (EIS) is the main technique used to identify the occurrence of these different processes, but when this technique is used without an explicit model describing the kinetics it is difficult to unravel the interdependence of each of these processes. The purpose of this dissertation is to identify the heterogeneous reactions occurring at the cathode of an SOFC by combining experimental EIS results with mathematical models describing the time dependent behavior of the system. This analysis is performed on two different systems. In the first case, experimental EIS results from patterned half cells composed of Ca-doped lanthanum manganite (LCM)| yttria-doped ZrO2 (YSZ) are modeled to investigate the temperature and partial pressure of oxygen, pO2, dependence of oxygen adsorption/dissociation onto the LCM surface, surface diffusion of atomic oxygen, and electrochemical reduction and incorporation of the oxygen into the electrolyte in the vicinity of the triple phase boundary (TPB). This model determines the time-independent state-space equations from which the Faradaic admittance transfer function is obtained. The

PERITONITIS DUE TO TRANSVERSE COLON PERFORATION: A RARE PRESENTATION

Directory of Open Access Journals (Sweden)

Vandana B.

2015-08-01

Full Text Available Abdominal tuberculosis is defined as infection of the peritoneum, hollow or solid abdominal organs with Mycobacterium tuberculi . TB can affect any part of the gastrointestinal (GI tract including anus, peritoneum and hepatobiliary system. The peritoneum and the ileocaecal region are the most likely sites of infection. The clinical manifestations of abdominal tuberculosis are nonspecific and mimic various GI disorders and cause delay in diagnosis and management. This pa thology has several complications, including free intestinal perforation.

Cathode-supported hybrid direct carbon fuel cells

DEFF Research Database (Denmark)

Gil, Vanesa; Gurauskis, Jonas; Deleebeeck, Lisa

2017-01-01

The direct conversion of coal to heat and electricity by a hybrid direct carbon fuel cell (HDCFC) is a highly efficient and cleaner technology than the conventional combustion power plants. HDCFC is defined as a combination of solid oxide fuel cell and molten carbonate fuel cell. This work...... investigates cathode-supported cells as an alternative configuration for HDCFC, with better catalytic activity and performance. This study aims to define the best processing route to manufacture highly efficient cathode-supported cells based on La0.75Sr0.25MnO3/yttria-stabilized zirconia infiltrated backbones...

Durability and Performance of High Performance Infiltration Cathodes

DEFF Research Database (Denmark)

Samson, Alfred Junio; Søgaard, Martin; Hjalmarsson, Per

2013-01-01

The performance and durability of solid oxide fuel cell (SOFC) cathodes consisting of a porous Ce0.9Gd0.1O1.95 (CGO) infiltrated with nitrates corresponding to the nominal compositions La0.6Sr0.4Co1.05O3-δ (LSC), LaCoO3-δ (LC), and Co3O4 are discussed. At 600°C, the polarization resistance, Rp......, varied as: LSC (0.062Ωcm2)cathode was found to depend on the infiltrate firing temperature and is suggested to originate...... of the infiltrate but also from a better surface exchange property. A 450h test of an LSC-infiltrated CGO cathode showed an Rp with final degradation rate of only 11mΩcm2kh-1. An SOFC with an LSC-infiltrated CGO cathode tested for 1,500h at 700°C and 0.5Acm-2 (60% fuel, 20% air utilization) revealed no measurable...

Scoring system for differentiating perforated and non-perforated pediatric appendicitis.

Science.gov (United States)

Blumfield, Einat; Yang, Daniel; Grossman, Joshua

2017-10-01

Appendicitis is the most common indication for emergency pediatric surgery and its most significant complication is perforation. Perforated appendicitis (PA) may be managed conservatively, whereas non-perforated appendicitis (NP) is managed surgically. Recent studies have shown that ultrasound (US) is effective for differentiating between PA and NP, and does not expose pediatric patients to ionizing radiation. The purpose of this study is to enhance the accuracy of differentiation with a novel scoring system based on clinical, laboratory, and US findings. This retrospective study included 243 patients aged 2-17 years who presented between 2006 and 2013 with surgically proven appendicitis, of whom 60 had perforation. Clinical and laboratory data were collected and US images evaluated by a pediatric radiologist. To create the scoring system, point values were assigned to each parameter. A randomly selected training sample of 137 subjects was used to create a scoring prediction model. The model was tested on the remaining 106 patients. Scores of ≥6, ≥11, and ≥15 yielded specificities of 64, 91, and 99%, and sensitivities of 96, 61, and 29%, respectively (p < 0.001). We have designed a scoring system incorporating clinical, laboratory, and sonographic findings which can differentiate PA from NP with high specificity.

Dimensional changes of alginate impression by using perforated and non-perforated ring trays

Directory of Open Access Journals (Sweden)

Sumadhi Sastrodihardjo

2010-03-01

Full Text Available Dimensional changes are a common occurrence in impressions, either during or after impression taking. It produces a difference in the dimensions of the object and the model, which leads to the restoration being ill-fitted. Several causal factors have been proposed such as friction between the impression material and the teeth, the bulk of the impression material, the type of impression materials used, the impression technique, the pouring time and many others. The exact causal factor is still unknown and the dimensional change mechanism is still poorly understood. The objective of this research was to investigate the role of the perforation on the ring trays in producing dimensional changes in the impression by using perforated and non-perforated ring trays. Alginate impressions were made on the frustum of cone metal master die with a 7.08 mm base diameter, 7.03 mm top diameter and 9.23 mm height using perforated and non-perforated ring trays with 9.40 mm in diameter and 14.17 mm in height. The dimensional change was determined by comparing the dimension of the dental stone die and its metal master die. The results showed that the percentage of dimensional changes that occurred by using perforated ring tray were (+ 0.56±0.40 on the top area, (- 3.54±2.92 on base area and (+ 1.54±0.83 in height, respectively. As compared to using non-perforated ring trays, the percentage of dimensional changes that occurred were (- 0.49±0.49 on top area, (- 8.76±3.95 on base area and (+ 1.19±0.71 in height, respectively. There was a significant difference in the direction of the dimensional changes on both the top areas, but not in the base areas and height.

Understanding the Role of Temperature and Cathode Composition on Interface and Bulk: Optimizing Aluminum Oxide Coatings for Li-Ion Cathodes

International Nuclear Information System (INIS)

Han, Binghong; Paulauskas, Tadas; Key, Baris; Peebles, Cameron; Park, Joong Sun

2017-01-01

Here, surface coating of cathode materials with Al_2O_3 has been shown to be a promising method for cathode stabilization and improved cycling performance at high operating voltages. However, a detailed understanding on how coating process and cathode composition changes the chemical composition, morphology and distribution of coating within cathode interface and bulk lattice, is still missing. In this study, we use a wet-chemical method to synthesize a series of Al_2O_3-coated LiNi_0_._5Co_0_._2Mn_0_._3O_2 and LiCoO_2 cathodes treated under various annealing temperatures and a combination of structural characterization techniques to understand the composition, homogeneity and morphology of coating layer and the bulk cathode. Nuclear magnetic resonance and electron microscopy results reveal that the nature of the interface is highly depended on the annealing temperature and cathode composition. For Al_2O_3-coated LiNi_0_._5Co_0_._2Mn_0_._3O_2, higher annealing temperature leads to more homogeneous and more closely attached coating on cathode materials, corresponding to better electrochemical performance. Lower Al_2O_3 coating content is found to be helpful to further improve the initial capacity and cyclability, which can greatly outperform the pristine cathode material. For Al_2O_3-coated LiCoO_2, the incorporation of Al into the cathode lattice is observed after annealing at high temperatures, implying the transformation from “surface coatings” to “dopants”, which is not observed for LiNi_0_._5Co_0_._2Mn_0_._3O_2. As a result, Al_2O_3-coated LiCoO_2 annealed at higher temperature shows similar initial capacity but lower retention compared to that annealed at a lower temperature, due to the intercalation of surface alumina into the bulk layered structure forming a solid solution.

Understanding the Role of Temperature and Cathode Composition on Interface and Bulk: Optimizing Aluminum Oxide Coatings for Li-Ion Cathodes.

Science.gov (United States)

Han, Binghong; Paulauskas, Tadas; Key, Baris; Peebles, Cameron; Park, Joong Sun; Klie, Robert F; Vaughey, John T; Dogan, Fulya

2017-05-03

Surface coating of cathode materials with Al 2 O 3 has been shown to be a promising method for cathode stabilization and improved cycling performance at high operating voltages. However, a detailed understanding on how coating process and cathode composition change the chemical composition, morphology, and distribution of coating within the cathode interface and bulk lattice is still missing. In this study, we use a wet-chemical method to synthesize a series of Al 2 O 3 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 and LiCoO 2 cathodes treated under various annealing temperatures and a combination of structural characterization techniques to understand the composition, homogeneity, and morphology of the coating layer and the bulk cathode. Nuclear magnetic resonance and electron microscopy results reveal that the nature of the interface is highly dependent on the annealing temperature and cathode composition. For Al 2 O 3 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 , higher annealing temperature leads to more homogeneous and more closely attached coating on cathode materials, corresponding to better electrochemical performance. Lower Al 2 O 3 coating content is found to be helpful to further improve the initial capacity and cyclability, which can greatly outperform the pristine cathode material. For Al 2 O 3 -coated LiCoO 2 , the incorporation of Al into the cathode lattice is observed after annealing at high temperatures, implying the transformation from "surface coatings" to "dopants", which is not observed for LiNi 0.5 Co 0.2 Mn 0.3 O 2 . As a result, Al 2 O 3 -coated LiCoO 2 annealed at higher temperature shows similar initial capacity but lower retention compared to that annealed at a lower temperature, due to the intercalation of surface alumina into the bulk layered structure forming a solid solution.

The improvement of all-solid-state electrochromic devices fabricated with the reactive sputter and cathodic arc technology

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Min-Chuan Wang

2016-11-01

Full Text Available The all-solid-state electrochromic device (ECD with the one substrate structure fabricated by the reactive dc magnetron sputtering (DCMS and cathodic vacuum arc plasma (CVAP technology has been developed for smart electrochromic (EC glass application. The EC layer and ion conductor layer were deposited by reactive DCMS and CVAP technology, respectively. The ion conductor layer Ta2O5 deposited by the CVAP technology has provided the better porous material structure for ion transportation and showed 1.76 times ion conductivity than devices with all sputtering process. At the same time, the EC layer WO3 and NiO deposited by the reactive DCMS have also provided the high quality and uniform characteristic to overcome the surface roughness effect of the CVAP ion conductor layer in multilayer device structure. The all-solid-state ECD with the CVAP ion conductor layer has demonstrated a maximum transmittance variation (ΔT of 55% at 550nm and a faster-switching speed. Furthermore, the lower equipment cost and higher deposition rate could be achieved by the application of CVAP technology.

High Performance Cathodes for Solid Oxide Fuel Cells Prepared by Infiltration of La0.6Sr0.4CoO32d into Gd-Doped Ceria

DEFF Research Database (Denmark)

Samson, Alfred Junio; Søgaard, Martin; Knibbe, Ruth

2011-01-01

Cathodes prepared by infiltration of La0.6Sr0.4CoO3d (LSC40) into a porous Ce0.9Gd0.1O1.95 (CGO10) backbone have been developed for low temperature solid oxide fuel cells. The CGO10 backbone has been prepared by screen printing a CGO10 ink on both sides of a 180 m dense CGO10 electrolyte......-tape followed by firing. LSC40 was introduced into the CGO10 porous backbone by multiple infiltrations of aqueous nitrate solutions followed by firing at 350C. A systematic study of the performance of the cathodes was performed by varying the CGO10 backbone firing temperature, the LSC40 firing temperature...... and the number of infiltrations. The cathode polarization resistance was measured using electrochemical impedance spectroscopy on symmetrical cells in ambient air, while the resulting structures were characterized by scanning electron microscopy (SEM) and high temperature X-ray diffraction (HT-XRD). The firing...

Delta neutrophil index: A reliable marker to differentiate perforated appendicitis from non-perforated appendicitis in the elderly.

Science.gov (United States)

Shin, Dong Hyuk; Cho, Young Suk; Kim, Yoon Sung; Ahn, Hee Cheol; Oh, Young Taeck; Park, Sang O; Won, Moo-Ho; Cho, Jun Hwi; Kim, Young Myeong; Seo, Jeong Yeol; Lee, Young Hwan

2018-01-01

Delta neutrophil index (DNI) is a new inflammatory marker and the present study aimed to evaluate the predictive value of the DNI for the presence of a perforation in elderly with acute appendicitis. This retrospective observational study was conducted on 108 consecutive elderly patients (≥65 years old) with acute appendicitis treated over a 24-month period. Sixty-nine of the 108 patients (median, IQR: 72, 67-77 years) were allocated to the perforated appendicitis group (63.9%) and 39 to the non-perforated appendicitis group (36.1%). WBC, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio and DNI were significantly higher in the perforated group. In multiple logistic regression analyses, initial DNI was the only independent marker that can significantly predict the presence of perforation in multiple regression [odds ratio 9.38, 95% confidence interval (2.51-35.00), P=.001]. Receiver operator characteristic curve analysis showed that DNI is a good predictor for the presence of appendiceal perforation at an optimal cut-off for DNI being 1.4% (sensitivity 67.7%, specificity 90.0%, AUC 0.807). Clinicians can reliably differentiate acute perforated appendicitis from non-perforated appendicitis by DNI level of 1.4 or more in elderly patients. © 2017 Wiley Periodicals, Inc.

CT findings of exophageal perforation

Energy Technology Data Exchange (ETDEWEB)

Heo, Jeong Nam; Choi, Yo Won; Jeon, Seok Chol; Park, Choong Ki; Hahm, Chang Kok [Hanyang University College of Medicine, Seoul (Korea, Republic of)

2002-09-01

To determine which CT findings are useful for the early disgnosis of esophageal perforation, and on the basis of these findings, to assess the accuracy of prediction of the perforation site. A review of medical records indicated that between January 1995 and December 2001, 36 patients with esophageal perforation were admitted to our hospital. Thirteen of these [M:F=8:5, age; 28-69 (mean, 52.4) years], who had undergone CT chest scanning, were included in this study. The causes of esophageal perforation were trauma (n=5), infectious diseases (n=4), Boerhaave syndrome (n=1), lung cancer (n=1), esophageal cancer (n=1), and idiopathic. Two chest radiologists unaware of the clinical findings reviewed the CT scans and predicted whether the upper or lower esophagus was perforated. The most common CT finding was extraluminal air at the posterior mediastinum (n=11), while other findings included pulmonary consolidation (n=10), pleural effusion (n=7), discontinuity of the esophageal wall (n=6) and subcutaneous emphysema (n=4), fluid collection around the esophagus (n-4), esophageal wall thickening (n=4), pneumothorax (n=2), and lung abscess (n=2). The perforation site was accurately predicted in 76.9% of cases (10/13). The CT findings which help the diagnosis of esophageal perforation, and prediction of the sites at which it occurs, are extraluminal air of fluid collection, focal defect of the esophageal wall, and esophageal wall thickening.

CT findings of exophageal perforation

International Nuclear Information System (INIS)

Heo, Jeong Nam; Choi, Yo Won; Jeon, Seok Chol; Park, Choong Ki; Hahm, Chang Kok

2002-01-01

To determine which CT findings are useful for the early disgnosis of esophageal perforation, and on the basis of these findings, to assess the accuracy of prediction of the perforation site. A review of medical records indicated that between January 1995 and December 2001, 36 patients with esophageal perforation were admitted to our hospital. Thirteen of these [M:F=8:5, age; 28-69 (mean, 52.4) years], who had undergone CT chest scanning, were included in this study. The causes of esophageal perforation were trauma (n=5), infectious diseases (n=4), Boerhaave syndrome (n=1), lung cancer (n=1), esophageal cancer (n=1), and idiopathic. Two chest radiologists unaware of the clinical findings reviewed the CT scans and predicted whether the upper or lower esophagus was perforated. The most common CT finding was extraluminal air at the posterior mediastinum (n=11), while other findings included pulmonary consolidation (n=10), pleural effusion (n=7), discontinuity of the esophageal wall (n=6) and subcutaneous emphysema (n=4), fluid collection around the esophagus (n-4), esophageal wall thickening (n=4), pneumothorax (n=2), and lung abscess (n=2). The perforation site was accurately predicted in 76.9% of cases (10/13). The CT findings which help the diagnosis of esophageal perforation, and prediction of the sites at which it occurs, are extraluminal air of fluid collection, focal defect of the esophageal wall, and esophageal wall thickening

Current management of peptic ulcer perforations

International Nuclear Information System (INIS)

Menakuru, S.R.

2004-01-01

Perforation is a life-threatening complication of peptic ulcer disease. Smoking and use of non-steroidal anti-inflammatory drugs are important risk factors for perforation. Diagnosis is made clinically and confirmed by the presence of pneumoperitoneum on radiographs. Nonoperative management is successful in patients identified to have a spontaneously sealed perforation proven by water-soluble contrast gastroduodenogram. Operative management consists of the time-honoured practice of mental patch closure, but now this can be done by laparoscopic methods. The practice of addition of acid-reducing procedures is currently being debated though it continues to be recommended in good-risk patients. Laparoscopic approaches to closure of duodenal perforation are now being applied widely and may become the gold standard in the future especially in patients with < 10 mm perforation size presenting within the first 24 hours of onset of pain. The role of Helicobacter pylori in duodenal ulcer perforation is controversial and more studies are needed to answer this question though recent indirect evidence suggests that eradicating H pylori may reduce the necessity for adding acid reducing procedures and the associated morbidity. Perforation is a life-threatening complication of peptic ulcer disease. The management of peptic ulcer disease has evolved over the decades, due to advances in operative techniques, bacteriology and pharmacology. While the recognition of the role of Helicobacter pylori (H. pylori) in peptic ulceration has resulted in a paradigm shift in the management of uncomplicated peptic ulcers, debate continues about the appropriate management of perforated duodenal bulb and prepyloric ulcers. A new dimension has been added to this controversy by the advent of laparoscopic techniques for closing the perforation. A Medline search of all articles dealing with the management of peptic ulcer perforation published after 1985 was undertaken. The short listed articles were

Glove Perforations During Interventional Radiological Procedures

International Nuclear Information System (INIS)

Leena, R. V.; Shyamkumar, N. K.

2010-01-01

Intact surgical gloves are essential to avoid contact with blood and other body fluids. The objective of this study was to estimate the incidence of glove perforations during interventional radiological procedures. In this study, a total of 758 gloves used in 94 interventional radiological procedures were examined for perforations. Eleven perforations were encountered, only one of which was of occult type. No significant difference in the frequency of glove perforation was found between the categories with varying time duration.

Bulk solid state rechargeable lithium ion battery fabrication with Al-doped Li7La3Zr2O12 electrolyte and Cu0.1V2O5 cathode

International Nuclear Information System (INIS)

Jin, Ying; McGinn, Paul J.

2013-01-01

A simple, low-temperature route was developed to process bulk solid-state Li-ion batteries employing Al-doped Li 7 La 3 Zr 2 O 12 solid electrolyte (thickness: ∼ 0.5 mm; 25 °C conductivity: ∼ 2 × 10 −4 S cm −1 ). A composite Cu 0.1 V 2 O 5 –based slurry was directly painted on Li 7 La 3 Zr 2 O 12 and dried at 120 °C to prepare the cathode film. The opposite side of the electrolyte was subsequently exposed to molten Li to form the anode. The discharge capacity of the solid state battery was 53 mAh g −1 (calculated based on the weight of active cathode material) at room temperature with 5 μA cm −2 discharging current. Severe capacity decay occurred after the initial discharging. A comparable liquid electrolyte battery was tested at room temperature for comparison and had a much slower decay rate. However, when the operating temperature of the solid state battery was increased to 50 °C, the cell performance significantly improved. At 50 °C, the battery exhibited 176 mAh g −1 initial discharging capacity at 5 μA cm −2 current density and 93 mAh g −1 initial capacity under a 10 μA cm −2 discharging current density. After 20 cycles, the capacity decayed to 68.6 mAh g −1 when cycled at a 10 μA cm −2 current density. Impedance spectroscopy was used to investigate the interface resistance of the battery at different temperatures. The results indicated that both the cathode and anode interface resistance were dramatically reduced at 50 °C. The decrease in interface resistances at elevated temperature is proposed as the main reason for the observed battery performance enhancement

Helicobacter pylori in gastroduodenal perforation

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Bharat B Dogra

2014-01-01

Full Text Available Background:peptic ulcers were earlier believed to be caused by dietary factors, gastric acid, and stress. However, in 1983, Warren and Marshall identified the correlation between Helicobacter pylori (H. pylori and peptic ulcers. It is now well established that most of the peptic ulcers occur as a result of H. pylori infection. But the co-relation between perforated peptic ulcer and H. pylori infection is not yet fully established. Aims and objectives : to study the prevalence of H. pylori infection in patients with perforated peptic ulcer. Materials and methods: this was a prospective study carried out in all cases of perforated peptic ulcer reporting in surgical wards of a medical college during 2008-2010. A total of 50 cases, presenting as acute perforation of duodenum and stomach during this period, formed the study group. After resuscitation, all the cases were subjected to emergency exploratory laparotomy. The exact site of perforation was identified, biopsy was taken from the ulcer margin from 2-3 sites and the tissue was sent for H. pylori culture and histopathological examination. Simple closure of perforation, omentoplasty, thorough peritoneal lavage and drainage was carried out. Results: out of the 50 cases of perforated peptic ulcer, 38 happened to be males, and only 12 were females. The age of the patients ranged from 20 to 70 years. All the patients underwent only emergency laparotomy. As many as 46 cases (92% turned out to be positive for H. pylori and only four cases (8% were negative for this infection. Postoperatively, patients who were found to be positive for H. pylori were put on anti-H. pylori treatment. Conclusion: there was a high prevalence of H. pylori infection in patients with perforated gastroduodenal ulcers.

Spectrum of perforation peritonitis in delhi: 77 cases experience.

Science.gov (United States)

Yadav, Dinesh; Garg, Puneet K

2013-04-01

Perforation peritonitis is the most common surgical emergency encountered by surgeons all over the world as well in India. The spectrum of etiology of perforation peritonitis in tropical countries continues to differ from its western counterpart. This study was conducted at Hindu Rao Hospital, Municipal Corporation of Delhi, New Delhi, India, designed to highlight the spectrum of perforation peritonitis in the eastern countries and to improve its outcome. This prospective study included 77 consecutive patients of perforation peritonitis studied in terms of clinical presentations, causes, site of perforation, surgical treatment, postoperative complications, and mortality at Hindu Rao Hospital, Delhi, from March 1, 2011 to December 1, 2011, over a period of 8 months. All patients were resuscitated and underwent emergency exploratory laparotomy. On laparotomy cause of perforation peritonitis was found and controlled. The most common cause of perforation peritonitis noticed in our series was perforated duodenal ulcer (26.4 %) and ileal typhoid perforation (26.4 %), each followed by small bowel tuberculosis (10.3 %) and stomach perforation (9.2 %), perforation due to acute appendicitis (5 %). The highest number of perforations was seen in ileum (39.1 %), duodenum (26.4 %), stomach (11.5 %), appendix (3.5 %), jejunum (4.6 %), and colon (3.5 %). Overall mortality was 13 %. The spectrum of perforation peritonitis in India continuously differs from western countries. The highest number of perforations was noticed in the upper part of the gastrointestinal tract as compared to the western countries where the perforations seen mostly in the distal part. The most common cause of perforation peritonitis was perforated duodenal ulcer and small bowel typhoid perforation followed by typhoid perforation. Large bowel perforations and malignant perforations were least common in our setup.

The management of large perforations of duodenal ulcers

Directory of Open Access Journals (Sweden)

Sharma Rajeev

2005-06-01

Full Text Available Abstract Background Duodenal ulcer perforations are a common surgical emergency, but literature is silent on the exact definition, incidence, management and complications of large perforations of duodenal ulcers. Methods The case files of 162 patients who underwent emergency laparotomy for duodenal ulcer perforations over a period of three years (2001 – 2003 were retrospectively reviewed and sorted into groups based on the size of the perforations – one group was defined as 'small 'perforations (less than 1 cm in diameter, another 'large' (when the perforation was more than 1 cm but less than 3 cms, and the third, 'giant'(when the perforation exceeded 3 cm. These groups of patients were then compared with each other in regard to the patient particulars, duration of symptoms, surgery performed and the outcome. Results A total of 40 patients were identified to have duodenal ulcer perforations more than 1 cm in size, thus accounting for nearly 25 % of all duodenal ulcer perforations operated during this period. These patients had a significantly higher incidence of leak, morbidity and mortality when compared to those with smaller perforations. Conclusion There are three distinct types of perforations of duodenal ulcers that are encountered in clinical practice. The first, are the 'small' perforations that are easy to manage and have low morbidity and mortality. The second are the 'large' perforations, that are also not uncommon, and omental patch closure gives the best results even in this subset of patients. The word 'giant' should be reserved for perforations that exceed 3 cms in diameter, and these are extremely uncommon.

LSM-YSZ Cathodes with Reaction-Infiltrated Nanoparticles

International Nuclear Information System (INIS)

Lu, Chun; Sholklapper, Tal Z.; Jacobson, Craig P.; Visco, StevenJ.; De Jonghe, Lutgard C.

2006-01-01

To improve the LSM-YSZ cathode performance of intermediate temperature solid oxide fuel cells (SOFCs), Sm0.6Sr0.4CoO3-sigma (SSC) perovskite nanoparticles are incorporated into the cathodes by a reaction-infiltration process. The SSC particles are ∼20 to 80nm in diameter, and intimately adhere to the pore walls of the preformed LSM-YSZ cathodes. The SSC particles dramatically enhance single-cell performance with a 97 percent H2+3 percent H2O fuel, between 600 C and 800 C. Consideration of a simplified TPB (triple phase boundary) reaction geometry indicates that the enhancement may be attributed to the high electrocatalytic activity of SSC for electrochemical reduction of oxygen in a region that can be located a small distance away from the strict triple phase boundaries. The implication of this work for developing high-performance electrodes is also discussed

Laparoscopic pyloroplasty for perforated peptic ulcer.

Science.gov (United States)

Grišin, Edvard; Mikalauskas, Saulius; Poškus, Tomas; Jotautas, Valdemaras; Strupas, Kęstutis

2017-09-01

Peptic ulcer is a common disease affecting millions of people every year. Despite improved understanding and treatment of the disease, the number of patients admitted with duodenal peptic ulcer perforation has not decreased. Deaths from peptic ulcer disease overcome other common emergency situations. Laparoscopic repair of the perforated peptic ulcer (PPU) is the gold standard approach for simple perforation. However, in patients with large perforated chronic ulcers laparotomy with pyloroplasty is the standard treatment. It is generally accepted to perform open surgery in PPU emergencies because of the greater knowledge and experience gathered over the past decades and less potential harm for the patient or surgical complications. We present a case of successful laparoscopic pyloroplasty of a perforated duodenal ulcer with stenosis.

Solid Oxide Fuel Cell Cathodes. Unraveling the Relationship Between Structure, Surface Chemistry and Oxygen Reduction

Energy Technology Data Exchange (ETDEWEB)

Gopalan, Srikanth [Boston Univ., MA (United States)

2013-03-31

In this work we have considered oxygen reduction reaction on LSM and LSCF cathode materials. In particular we have used various spectroscopic techniques to explore the surface composition, transition metal oxidation state, and the bonding environment of oxygen to understand the changes that occur to the surface during the oxygen reduction process. In a parallel study we have employed patterned cathodes of both LSM and LSCF cathodes to extract transport and kinetic parameters associated with the oxygen reduction process.

CLINICAL STUDY OF DUODENAL PERFORATION

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Sambasiva Rao

2016-04-01

Full Text Available BACKGROUND The duodenal injury can pose a formidable challenge to the surgeon and failure to manage it properly may have devastating results. Over the centuries, there was little to offer the patient of acute abdomen beyond cupping, purgation and enemas, all of which did more harm than good. It was not until 1884 that Mikulicz made an attempt to repair a perforation. Recent statistics indicate roughly 10% of population develop gastric or duodenal ulcer in life time. Roughly 1-3% of population above the age of 20 years have some degree of peptic ulcer activity during any annual period. A detailed history with regards to the signs and symptoms of the patient, a meticulous examination, radiological and biochemical investigations help to arrive at a correct preoperative diagnosis. In this study, a sincere effort has been put to understand the demographic patterns, to understand the underlying aetiology and to understand the effectiveness of the standard methods of investigation and treatment in use today. METHODS This is a 24 months prospective study i.e., from September 2011 to September 2013 carried out at Dr. Pinnamaneni Siddhartha Institute of Medical Sciences & Research Foundation. The study included the patients presenting to Dr. Pinnamaneni Siddhartha Institute of Medical Sciences & Research Foundation to emergency ward with signs and symptoms of hollow viscus perforation. The sample size included 30 cases of duodenal perforation. RESULTS Duodenal ulcer perforation commonly occurs in the age group of 30-60 years, but it can occur in any age group. Majority of the patients were male. Smoking and alcohol consumption were risk factors in most cases (53.3% for the causation of duodenal ulcer perforation. Sudden onset of abdominal pain, situated at epigastrium and right hypochondrium was a constant symptom (100%. Vomiting, constipation and fever were not so common. CONCLUSION The emergency surgical management for perforated duodenal ulcer is by

A perforated diverticulum in Cushing's disease

OpenAIRE

de Havenon, Adam; Ehrenkranz, Joel

2011-01-01

We report a case of perforated colonic diverticulum in Cushing's disease. Although perforated diverticuli have been described in patients with Cushing's syndrome secondary to exogenous glucocorticoids, this complication has not been described in patients with Cushing's disease. Patients with hypercortisolism, from either exogenous or endogenous sources, should be monitored for diverticular perforation.

Testing Iodine as a New Fuel for Cathodes

Science.gov (United States)

Glad, Harley; Branam, Richard; Rogers, Jim; Warren, Matthew; Burleson, Connor; Siy, Grace

2017-11-01

The objective of this research is to demonstrate the viability of using iodine as an alternative space propulsion propellant. The demonstration requires the testing of a cathode with xenon and then the desired element iodine. Currently, cathodes run on noble gases such as xenon which must be stored in high pressure canisters and is very expensive. These shortcomings have led to researching possible substitutes. Iodine was decided as a suitable candidate because it's cheaper, can be stored as a solid, and has similar mass properties as xenon. In this research, cathodes will be placed in a vacuum chamber and operated on both gases to observe their performance, allowing us to gain a better understanding of iodine's behavior. Several planned projects depend on the knowledge gained from this project, such as larger scaled tests and iodine fed hall thrusters. The tasks of this project included protecting the stainless-steel vacuum chamber by gold plating and Teflon® coating, building a stand to hold the cathode, creating an anode resistant to iodine, and testing the cathode once setup was complete. The successful operation of the cathode was demonstrated. However, the experimental setup proved ineffective at controlling the iodine flow. Current efforts are focused on this problem. REU Site: Fluid Mechanics with Analysis using Computations and Experiments NSF Grant EEC 1659710.

Synthesis cathode material LiNi0.80Co0.15Al0.05O2 with two step solid-state method under air stream

Science.gov (United States)

Xia, Shubiao; Zhang, Yingjie; Dong, Peng; Zhang, Yannan

2014-01-01

A facile generic strategy of solid-state reaction under air atmosphere is employed to prepare LiNi0.8Co0.15Al0.05O2 layer structure micro-sphere as cathodes for Li-ion batteries. The impurity phase has been eliminated wholly without changing the R-3m space group of LiNi0.8Co0.15Al0.05O2. The electrochemical performance of LiNi0.8Co0.15Al0.05O2 cathodes depend on the sintering step, temperature, particle size and uniformity. The sample pre-sintered at 540 °C for 12 h and then sintered at 720 °C for 28 h exhibits the best electrochemical performance, which delivers a reversible capacity of 180.4, 165.8, 154.7 and 135.6 mAhg-1 at 0.2 C, 1 C, 2 C and 5 C, respectively. The capacity retention keeps over 87% after 76 cycles at 1 C. This method is simple, cheap and mass-productive, and thus suitable to large scale production of NCA cathodes directly used for lithium ion batteries.

CLINICAL STUDY AND MANAGEMENT OF BENIGN GASTROINTESTINAL PERFORATIONS

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Kishan

2016-05-01

Full Text Available INTRODUCTION Peritonitis due to gastrointestinal perforation is one of the commonest surgical emergencies encountered by a general surgeon. (1,2 Mortality and morbidity is still very high despite early diagnosis and intensive management. This study is aimed to find common causes of perforations, its presentations, mode of investigations and treatment done and outcome of patients. METHODS Case records of all patients, in exclusion and inclusion criteria, who were admitted in emergency surgical ward with suspected GI perforation and peritonitis were included in study and diagnosis confirmed by either investigations preoperatively or by laparotomy and results analysed over a period of 16 months. RESULTS GI perforations due to benign causes are most common causes of peritonitis, of which gastroduodenal perforations are commonest followed by appendicular perforation closely followed by infective perforations. CONCLUSION Benign causes of upper gastroduodenal perforations are common causes of peritonitis (2,3. Mortality increases with delay in presentation and treatment. Abdominal signs like guarding rigidity are present in majority of cases. X-ray erect abdomen was effective in detecting perforation in majority of cases. Surgery is the treatment in all cases of perforation.

Perforated peptic ulcer

DEFF Research Database (Denmark)

Søreide, Kjetil; Thorsen, Kenneth; Harrison, Ewen M

2015-01-01

Perforated peptic ulcer is a common emergency condition worldwide, with associated mortality rates of up to 30%. A scarcity of high-quality studies about the condition limits the knowledge base for clinical decision making, but a few published randomised trials are available. Although Helicobacter...... need further assessment. Adequate trials with low risk of bias are urgently needed to provide better evidence. We summarise the evidence for perforated peptic ulcer management and identify directions for future clinical research....

CT features for the detection of bowel perforation sites by blunt abdominal trauma

International Nuclear Information System (INIS)

Yeon, Jae Woo; Kim, Mi Young; Suh, Chang Hae; Cho, Young Up

1996-01-01

We evaluated the CT criteria useful for the diagnosis of the site of bowel perforation in patients with this or mesenteric injury caused by blunt abdominal trauma. CT findings of 26 patients with blunt abdominal trauma were retrospectively analyzed by two observers who were unaware of operative findings, and the results of their analysis were compared with those findings. Twenty cases of bowel perforation found at the jejunum (8), ileum (9), and colon (3), and six cases of mesenteric injuries were confirmed by operation. We evaluated CT findings of 1) segmental bowel wall thickening, b) focal mesenteric fat infiltration, c) loculated fluid collection and d) extraluminal air adjacent to the bowel, and in addition analyzed the locations of ascites and free air, and the associated injuries of solid organs. The most common finding at the site of bowel perforation was segmental bowel wall thickening (17 cases), followed by focal mesenteric fat infiltration (12 cases), loculated fluid (12 cases) and extraluminal air ajacent to the bowel (9 cases). Segmental bowel wall thickening was present at 34 sites, and the perforations were confirmed at 17 of these(50%). Focal mesenteric fat infiltration was present at 19 sites;the perforations were proven at 12(63%). Loculated fluid collections were confirmed at 12/20 sites(60%), and extraluminal air adjacent to the bowel at 9/12(75%). The positive predictive value of criteria a, b, d, c) was 100%, and the positive predictive values of a, b, c) and a, d) were 60 and 67%, respectively. We observed ascites in 16 cases and intraperitoneal free air in 8 cases, the locations of ascites and free air did not, however, significantly correlate with the perforation sites. Extraluminal air adjacent to the bowel was the most specific criterion, and segmental bowel wall thickening was the most sensitive criterion. of all criteria, the finding 'a, b, c, d' most accurately predicted the site of bowel perforation

Electrochemical performance of Nd1.8Ce0.2CuO4+δ:Ce0.9Gd0.1O2 composite cathode for intermediate temperature solid oxide fuel cells

International Nuclear Information System (INIS)

Khandale, A.P.; Bhoga, S.S.

2012-01-01

Intermediate temperature solid oxide fuel cells (IT-SOFCs) are viewed as a promising power generation systems with high efficiency and low pollution. Recently, mixed ionic-electronic conductors (MIECs), with K 2 NiF 4 - type structure, attracted much attention as cathode for IT-SOFC

Cermet cathodes for strontium and magnesium-doped LaGaO{sub 3}-based solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Datta, Pradyot [Technische Universitaet Clausthal, Institut fuer Metallurgie, 42 Robert-Koch Strasse, 38678 Clausthal-Zellerfeld (Germany); Max-Planck-Institut fuer Metallforschung and Institut fuer Nichtmetallische and Anorganische Materialien, Universitaet Stuttgart, Pulvermetallurgisches Laboratorium, Heisenbergstrasse 3, Stuttgart 70569 (Germany)], E-mail: pradyot.datta@gmail.com; Bronin, D.I. [Institute of High-Temperature Electrochemistry of Russian Academy of Sciences, Ekaterinburg 620219, S. Kovalevskoz 22 (Russian Federation); Majewski, P. [University of South Australia, School of Advanced Manufacturing and Mechanical Engineering, Mawson Institute, Mawson Lakes, South Australia 5095 (Australia); Aldinger, F. [Max-Planck-Institut fuer Metallforschung and Institut fuer Nichtmetallische and Anorganische Materialien, Universitaet Stuttgart, Pulvermetallurgisches Laboratorium, Heisenbergstrasse 3, Stuttgart 70569 (Germany)

2009-03-15

To check the suitability of La{sub 0.9}Sr{sub 0.1}Ga{sub 0.85}Mg{sub 0.15}O{sub 3-{delta}}-Ag cermets as cathode material for solid oxide fuel cell (SOFC) with Sr- and Mg-doped LaGaO{sub 3} electrolyte a series of cermets with different Ag contents were prepared by conventional sintering process. The chemical compatibility between La{sub 0.9}Sr{sub 0.1}Ga{sub 0.85}Mg{sub 0.15}O{sub 3-{delta}} (LSGM) and Ag was investigated by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Thermal expansion coefficient of the cermets was measured as a function of Ag content and was found to increase with increasing metallic content. Oxygen adsorption at the surface of the cermets could be detected but no reaction or solid solubility between LSGM and Ag was found. It was noticed that a minimum of 30 wt.% Ag is needed to form a cermet with percolating network. From impedance spectroscopy measurement activation energy for the polarization conductance was found to be around 110 kJ mol{sup -1}.

Optimization of geometrical characteristics of perforated plates

International Nuclear Information System (INIS)

Radisavljevic, Igor; Balos, Sebastian; Nikacevic, Milutin; Sidjanin, Leposava

2013-01-01

Highlights: ► Perforated plate are tested against 12.7 mm API projectile. ► Perforations similar to the projectile diameter offer more efficient core fracture. ► Larger perforations gave a more efficient core fragmentation. ► SEM microscopy analysis has shown a ductile fracture mode at impact point. - Abstract: In this paper, an attempt was made to design effective non-homogenous armor in form of perforated plate mounted at close distance from basic armor plate. Perforated plate with three perforation diameters: 9, 10 and 11 mm, two ligaments length: 3.5 and 4.5 mm ligaments, set at 0° and 28° angles, were combined to 13 mm basic plate and tested against 12.7 mm API ammunition. It has been shown that larger perforations gave a more efficient core fragmentation, while angled specimens were the only ones that offer full protection against five API shots when the perforated plate was placed at 100 mm from the basic plate. Perforations that are similar in size to the penetrating core diameter offer a more efficient core fracture, leading to a faster fragment separation. This may enable a smaller distance between the add-on perforated and basic plate to be used. Scanning electron microscopy analysis has shown a ductile fracture mode at impact point, with hardness values on plate basic level. On the other hand, a brittle fracture mode with a rise in local hardness measured near impact point is a result of intensive high speed plastic deformation produced by bending stresses. A drop in local hardness measured near impact point, may be the result of intensive cracking that occur due to repeated projectile impact

The electrochemical reduction processes of solid compounds in high temperature molten salts.

Science.gov (United States)

Xiao, Wei; Wang, Dihua

2014-05-21

Solid electrode processes fall in the central focus of electrochemistry due to their broad-based applications in electrochemical energy storage/conversion devices, sensors and electrochemical preparation. The electrolytic production of metals, alloys, semiconductors and oxides via the electrochemical reduction of solid compounds (especially solid oxides) in high temperature molten salts has been well demonstrated to be an effective and environmentally friendly process for refractory metal extraction, functional materials preparation as well as spent fuel reprocessing. The (electro)chemical reduction of solid compounds under cathodic polarizations generally accompanies a variety of changes at the cathode/melt electrochemical interface which result in diverse electrolytic products with different compositions, morphologies and microstructures. This report summarizes various (electro)chemical reactions taking place at the compound cathode/melt interface during the electrochemical reduction of solid compounds in molten salts, which mainly include: (1) the direct electro-deoxidation of solid oxides; (2) the deposition of the active metal together with the electrochemical reduction of solid oxides; (3) the electro-inclusion of cations from molten salts; (4) the dissolution-electrodeposition process, and (5) the electron hopping process and carbon deposition with the utilization of carbon-based anodes. The implications of the forenamed cathodic reactions on the energy efficiency, chemical compositions and microstructures of the electrolytic products are also discussed. We hope that a comprehensive understanding of the cathodic processes during the electrochemical reduction of solid compounds in molten salts could form a basis for developing a clean, energy efficient and affordable production process for advanced/engineering materials.

Novel layered perovskite GdBaCoFeO{sub 5+{delta}} as a potential cathode for proton-conducting solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Ding, Hanping; Xue, Xingjian [Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208 (United States)

2010-05-15

While cobalt-containing perovskite-type cathode materials facilitate the activation of oxygen reduction, they also suffer from problems like poor chemical stability in CO{sub 2}, high thermal expansion coefficients, etc. Partial B site substitution with Fe element is expected to be able to mitigate these problems while keeping high catalyst performance. In this paper, a layered perovskite GdBaCoFeO{sub 5+{delta}} (GBCF) was developed as a cathode material for protonic ceramic membrane fuel cells (PCMFCs) based on proton-conducting electrolyte of stable BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.2}O{sub 3-{delta}} (BZCY7). The button cells of Ni-BZCY7 vertical stroke BZCY7 vertical stroke GBCF were fabricated and tested from 600 to 700 C with humidified H{sub 2} ({proportional_to}3% H{sub 2}O) as a fuel and ambient oxygen as oxidant. An open-circuit potential of 1.002 V, maximum power density of 482 mW cm{sup -2}, and a low electrode polarization resistance of 0.11 {omega}cm{sup 2} were achieved at 700 C. The experimental results indicated that the layered perovskite GBCF is a good candidate for cathode material, while the developed Ni-BZCY7 vertical stroke BZCY7 vertical stroke GBCF cell is a promising functional material system for intermediate temperature solid oxide fuel cells. (author)

Spectroscopic and Electrochemical Properties of Lithium-Rich LiFePO4 Cathode Synthesized by Solid-State Reaction

Science.gov (United States)

Rosaiah, P.; Hussain, O. M.; Zhu, Jinghui; Qiu, Yejun

2017-08-01

Lithium iron phosphate (Li x FePO4) is synthesized by a solid-state reaction method. The structural, electrical and electrochemical properties are studied in detail. It is found that the increment of lithium concentration (up to x = 1.05) does not affect the structure of LiFePO4 but improves its electrical conductivity as well as electrochemical performance. Surface morphological studies exhibited the formation of rod-like nanoparticles with small size. Electric and dielectric properties are also investigated over a frequency range of 1 Hz-1 MHz at different temperatures. The conductivity increased with increasing temperature, which follows the Arrhenius relation with the activation energy of about 0.31 eV. And the electrochemical tests found that the Li1.05FePO4 cathode possessed improved discharge capacity with better cycling performance.

Solid Rocket Motor Design Using Hybrid Optimization

Directory of Open Access Journals (Sweden)

Kevin Albarado

2012-01-01

Full Text Available A particle swarm/pattern search hybrid optimizer was used to drive a solid rocket motor modeling code to an optimal solution. The solid motor code models tapered motor geometries using analytical burn back methods by slicing the grain into thin sections along the axial direction. Grains with circular perforated stars, wagon wheels, and dog bones can be considered and multiple tapered sections can be constructed. The hybrid approach to optimization is capable of exploring large areas of the solution space through particle swarming, but is also able to climb “hills” of optimality through gradient based pattern searching. A preliminary method for designing tapered internal geometry as well as tapered outer mold-line geometry is presented. A total of four optimization cases were performed. The first two case studies examines designing motors to match a given regressive-progressive-regressive burn profile. The third case study studies designing a neutrally burning right circular perforated grain (utilizing inner and external geometry tapering. The final case study studies designing a linearly regressive burning profile for right circular perforated (tapered grains.

Multiple, Pan-Enteric Perforation Secondary to Intestinal Tuberculosis

Science.gov (United States)

Masood, Irfan; Majid, Zain; Rafiq, Ali; Rind, Waqas; Zia, Aisha; Raza, Sajjad

2015-01-01

Free perforation is one of the most feared complications of the intestinal tuberculosis. The terminal ileum is the most common site of perforation, while the majority of (90%) perforations are solitary. Herein, we describe a case of a 25-year-old male who presented with generalized peritonitis requiring an emergency exploratory laparotomy, which revealed pan-enteric perforation characterized by multiple perforations of the small bowel extending 10–15 cm from the DJ flexure up to the terminal ileum. The perforations were primarily closed, while 6–8 cm of the diseased terminal ileum was resected and the two ends were brought out as double-barreled ostomy. To the best of our knowledge, such an extensive tuberculous perforation of the small bowel has not been previously reported in the literature before. PMID:26798540

Mortality risk factor analysis in colonic perforation: would retroperitoneal contamination increase mortality in colonic perforation?

Science.gov (United States)

Yoo, Ri Na; Kye, Bong-Hyeon; Kim, Gun; Kim, Hyung Jin; Cho, Hyeon-Min

2017-10-01

Colonic perforation is a lethal condition presenting high morbidity and mortality in spite of urgent surgical treatment. This study investigated the surgical outcome of patients with colonic perforation associated with retroperitoneal contamination. Retrospective analysis was performed for 30 patients diagnosed with colonic perforation caused by either inflammation or ischemia who underwent urgent surgical treatment in our facility from January 2005 to December 2014. Patient characteristics were analyzed to find risk factors correlated with increased postoperative mortality. Using the Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity (POSSUM) audit system, the mortality and morbidity rates were estimated to verify the surgical outcomes. Patients with retroperitoneal contamination, defined by the presence of retroperitoneal air in the preoperative abdominopelvic CT, were compared to those without retroperitoneal contamination. Eight out of 30 patients (26.7%) with colonic perforation had died after urgent surgical treatment. Factors associated with mortality included age, American Society of Anesthesiologists (ASA) physical status classification, and the ischemic cause of colonic perforation. Three out of 6 patients (50%) who presented retroperitoneal contamination were deceased. Although the patients with retroperitoneal contamination did not show significant increase in the mortality rate, they showed significantly higher ASA physical status classification than those without retroperitoneal contamination. The mortality rate predicted from Portsmouth POSSUM was higher in the patients with retroperitoneal contamination. Patients presenting colonic perforation along with retroperitoneal contamination demonstrated severe comorbidity. However, retroperitoneal contamination was not found to be correlated with the mortality rate.

Facilely solving cathode/electrolyte interfacial issue for high-voltage lithium ion batteries by constructing an effective solid electrolyte interface film

International Nuclear Information System (INIS)

Xu, Jingjing; Xia, Qingbo; Chen, Fangyuan; Liu, Tao; Li, Li; Cheng, Xueyuan; Lu, Wei; Wu, Xiaodong

2016-01-01

The cathode/electrolyte interface stability is the key factor for the cyclic performance and the safety performance of lithium ion batteries. Suppression of consuming key elements in the electrode materials is essential in this concern. In this purpose, we investigate a facile strategy to solve interfacial issue for high-voltage lithium ion batteries by adding an oxidable fluorinated phosphate, Bis(2,2,2-trifluoroethyl) Phosphite (BTFEP), as a sacrificial additive in electrolyte. We demonstrate that BTFEP additive could be oxidized at slightly above 4.28 V which is a relatively lower voltage than that of solvents, and the oxidative products facilitate in-situ forming a stable solid electrolyte interphase (SEI) film on the cathode surface. The results manifest the SEI film validly restrains the generation of HF and the interfacial side reaction between high-voltage charged LiNi 0.5 Mn 1.5 O 4 (LNMO) and electrolyte, hence, the dissolution of Mn and Ni is effectively suppressed. Finally, the cyclic performance of LNMO after 200 cycles was remarkably improved from 68.4% in blank electrolyte to 95% in 1 wt% BTFEP-adding electrolyte.

Impregnation of LSM Based Cathodes for Solid Oxide Fuel Cells

DEFF Research Database (Denmark)

Højberg, Jonathan; Søgaard, Martin

2011-01-01

Composites cathodes consisting of strontium doped lanthanum manganite (LSM) and yttria stabilized zirconia have been impregnated with the nitrates corresponding to the nominal compositions: La0.75Sr0.25Mn1.05O3 +/-delta (LSM25), Ce0.8Sm0.2O2 (SDC) and a combination of both (dual). The latter...

Multiple, Pan-Enteric Perforation Secondary to Intestinal Tuberculosis

Directory of Open Access Journals (Sweden)

Irfan Masood

2015-01-01

Full Text Available Free perforation is one of the most feared complications of the intestinal tuberculosis. The terminal ileum is the most common site of perforation, while the majority of (90% perforations are solitary. Herein, we describe a case of a 25-year-old male who presented with generalized peritonitis requiring an emergency exploratory laparotomy, which revealed pan-enteric perforation characterized by multiple perforations of the small bowel extending 10–15 cm from the DJ flexure up to the terminal ileum. The perforations were primarily closed, while 6–8 cm of the diseased terminal ileum was resected and the two ends were brought out as double-barreled ostomy. To the best of our knowledge, such an extensive tuberculous perforation of the small bowel has not been previously reported in the literature before.

STUDY OF CLINICAL OUTCOMES OF SUBFASCIAL PERFORATOR LIGATION SURGERY IN PERFORATOR INCOMPETENCE

Directory of Open Access Journals (Sweden)

Vasuki Rajam

2017-02-01

Full Text Available BACKGROUND Chronic venous insufficiency presents with a spectrum of clinical features ranging from pain or heaviness of affected limbs to non-healing ulcers over the lower limbs and usually require some form of surgical intervention, performing direct perforator vein division preferably by subfascial endoscopic perforator ligation surgery for perforator incompetence, as despite aggressive conservative therapy including compression, lifestyle modification and venotonic medications which are of high cost treatment with increased risk of increasing symptoms. MATERIALS AND METHODS A prospective longitudinal clinical study of 30 patients selected by systematic sampling method from November 2014 to September 2015 at our institution was conducted to determine the results of subfascial endoscopic perforator vein surgery (SEPS in perforator incompetence. RESULTS For venous clinical severity scoring pre operatively and after 3 weeks post-surgery, the mean for VCSS pre-operatively was 6.66 and a standard deviation of 2.399. The T value was calculated and was found to be 4.9321 and p value of 0.00001(p value less than 0.05 is significant. Similarly for the cases with active ulcer, the size assessment pre-operatively and post-SEPS was again analysed using student t test and the mean ulcer size prior to surgery was found to be 3.3 and standard deviation of 1.984. The T value was calculated and was found to be 1.789009 and a p value of 0.04 (p value less than 0.05 is significant. CONCLUSION Our study concluded that favourable and significant ulcer healing rate with improvement and reduction in clinical severity suggests that SEPS plays an important role in surgical management of advanced stages of venous insufficiency.

Electron beam produced in a transient hollow cathode discharge: beam electron distribution function, X-ray emission and solid target ablation

International Nuclear Information System (INIS)

Nistor, Magdalena

2000-01-01

This research thesis aims at a better knowledge of phenomena occurring during transient hollow cathode discharges. The author first recalls the characteristics of such a discharge which make it different from conventional pseudo-spark discharges. The objective is to characterise the electron beam produced within the discharge, and the phenomena associated with its interaction with a solid or gaseous target, leading to the production of an X ray or visible radiation. Thus, the author reports the measurement (by magnetic deflection) of the whole time-averaged electronic distribution function. Such a knowledge is essential for a better use of the electron beam in applications such as X-ray source or material ablation. As high repetition frequency pulse X ray sources are very interesting tools, he reports the development and characterisation of Bremsstrahlung X rays during a beam-target interaction. He finally addresses the implementation of a spectroscopic diagnosis for the filamentary plasma and the ablation of a solid target by the beam [fr

Tricholithobezoar Causing Gastric Perforation

Directory of Open Access Journals (Sweden)

Juliana Santos Valenciano

2012-01-01

Full Text Available A bezoar is an intraluminal mass formed by the accumulation of undigested material in the gastrointestinal tract. Trichobezoar is a rare condition seen almost exclusively in young women with trichotillomania and trichotillophagia. When not recognized, the trichobezoar continues to grow, which increases the risk of severe complications such as gastric ulceration and even perforation. Formation of a gallstone within the trichobezoar (tricholithobezoar is an event that has not yet been described. We report the case of a 22-year-old woman admitted to the emergency room with signals and symptoms of an epigastric mass and perforative acute abdomen. Radiological study revealed bilateral pneumoperitoneum. Personal history revealed depressive syndrome, trichotillomania and trichophagia. With a diagnosis of visceral perforation, an urgent exploratory laparotomy was performed. This confirmed the diagnosis of gastric perforation due to a large trichobezoar with the formation of a gastrolith that was removed by anterior gastrotomy. Biochemical study of the gastric stone revealed that it was composed of bile salts. There were no complications. The patient was discharged on the 5th postoperative day and was referred for psychiatric treatment.

Investigation of barium-calcium aluminate process to manufacture and characterize impregnated thermionic cathode for power microwave devices

International Nuclear Information System (INIS)

Higashi, Cristiane

2006-01-01

In the present work it is described the barium calcium aluminate manufacture processes employed to produce impregnated cathodes to be used in a traveling-wave tube (TWT). The cathodes were developed using a tungsten body impregnated with barium and calcium aluminate with a 5:3:2 proportion (molar). Three different processes were investigated to obtain this material: solid-state reaction, precipitation and crystallization. Thermal analysis, thermogravimetry specifically, supported to determine an adequate preparation procedure (taking into account temperature, time and pyrolysis atmosphere). It was verified that the crystallization showed a better result when compared to those investigated (solid-state reaction and precipitation techniques - formation temperature is about 1000 deg C in hydrogen atmosphere), whereas it presented the lower formation temperature (800 deg C) in oxidizing atmosphere (O 2 ). It was used the practical work function distribution theory (PWFD) of Miram to characterize thermionic impregnated cathode. The PWFD curves were used to characterize the barium-calcium aluminate cathode. PWFD curves shown that the aluminate cathode work function is about 2,00 eV. (author)

Clinical applications of the superior epigastric artery perforator (SEAP) flap: anatomical studies and preoperative perforator mapping with multidetector CT.

Science.gov (United States)

Hamdi, Moustapha; Van Landuyt, Koenraad; Ulens, Sara; Van Hedent, Eddy; Roche, Nathalie; Monstrey, Stan

2009-09-01

Pedicled superior epigastric artery perforator (SEAP) flaps can be raised to cover challenging thoracic defects. We present an anatomical study based on multidetector computerized tomography (MDCT) scan findings of the SEA perforators in addition to the first reported clinical series of SEAP flaps in anterior chest wall reconstruction. (a) In the CT scan study, images of a group of 20 patients who underwent MDCT scan analysis were used to visualise bilaterally the location of musculocutaneous SEAP. X- and Y-axes were used as landmarks to localise the perforators. The X-axis is a horizontal line at the junction of sternum and xyphoid (JCX) and the Y-axis is at the midline. (b) In the clinical study, seven pedicled SEAP flaps were performed in another group of patients. MDCT images revealed totally 157 perforators with a mean of 7.85 perforators per patient. The dominant perforators (137 perforators) were mainly localised in an area between 1.5 and 6.5 cm from the X-axis on both sides and between 3 and 16 cm below the Y-axis. The calibre of these dominant perforators was judged as 'good' to 'very good' in 82.5% of the cases. The average dimension of the flap was 21.7x6.7 cm. All flaps were based on one perforator. Mean harvesting time was 110 min. There were no flap losses. Minor tip necrosis occurred in two flaps. One of them was treated with excision and primary closure. Our clinical experience indicates that the SEAP flap provides a novel and useful approach for reconstruction of anterior chest wall defects. CT-based imaging allows for anatomical assessment of the perforators of the superior epigastric artery (SEA).

Research on the Perforating Algorithm Based on STL Files

Science.gov (United States)

Yuchuan, Han; Xianfeng, Zhu; Yunrui, Bai; Zhiwen, Wu

2018-04-01

In the process of making medical personalized external fixation brace, the 3D data file should be perforated to increase the air permeability and reduce the weight. In this paper, a perforating algorithm for 3D STL file is proposed, which can perforate holes, hollow characters and engrave decorative patterns on STL files. The perforating process is composed of three steps. Firstly, make the imaginary space surface intersect with the STL model, and reconstruct triangles at the intersection. Secondly, delete the triangular facets inside the space surface and make a hole on the STL model. Thirdly, triangulate the inner surface of the hole, and thus realize the perforating. Choose the simple space equations such as cylindrical and rectangular prism equations as perforating equations can perforate round holes and rectangular holes. Through the combination of different holes, lettering, perforating decorative patterns and other perforated results can be accomplished. At last, an external fixation brace and an individual pen container were perforated holes using the algorithm, and the expected results were reached, which proved the algorithm is feasible.

Spectrum of perforation peritonitis in Pakistan: 300 cases Eastern experience.

Science.gov (United States)

Afridi, Shahida Parveen; Malik, Faiza; Ur-Rahman, Shafiq; Shamim, Shahid; Samo, Khursheed A

2008-11-08

Perforation peritonitis is the most common surgical emergency encountered by the surgeons all over the world as well in Pakistan. The spectrum of etiology of perforation peritonitis in tropical countries continues to differ from its western counter part. This study was conducted at Dow University of health sciences and Civil Hospital Karachi (DUHS & CHK) Pakistan, designed to highlight the spectrum of perforation peritonitis in the East and to improve its outcome. A prospective study includes three hundred consecutive patients of perforation peritonitis studied in terms of clinical presentations, Causes, site of perforation, surgical treatment, post operative complications and mortality, at (DUHS&CHK) Pakistan, from 1st September 2005 - 1st March 2008, over a period of two and half years. All patients were resuscitated underwent emergency exploratory laparotomy. On laparotomy cause of perforation peritonitis was found and controlled. The most common cause of perforation peritonitis noticed in our series was acid peptic disease 45%, perforated duodenal ulcer (43.6%) and gastric ulcer 1.3%. followed by small bowel tuberculosis (21%) and typhoid (17%). large bowel perforation due to tuberculosis 5%, malignancy 2.6% and volvulus 0.3%. Perforation due to acute appendicitis (5%). Highest number of perforations has seen in the duodenum 43.6%, ileum37.6%, and colon 8%, appendix 5%, jejunum 3.3%, and stomach 2.3%. Overall mortality was (10.6%). The spectrum of perforation peritonitis in Pakistan continuously differs from western country. Highest number of perforations noticed in the upper part of the gastrointestinal tract as compared to the western countries where the perforations seen mostly in the distal part. Most common cause of perforation peritonitis is perforated duodenal ulcer, followed by small bowel tuberculosis and typhoid perforation. Majority of the large bowel perforations are also tubercular. Malignant perforations are least common in our setup.

Spectrum of perforation peritonitis in Pakistan: 300 cases Eastern experience

Directory of Open Access Journals (Sweden)

Ur-Rahman Shafiq

2008-11-01

Full Text Available Abstract Background Perforation peritonitis is the most common surgical emergency encountered by the surgeons all over the world as well in Pakistan. The spectrum of etiology of perforation peritonitis in tropical countries continues to differ from its western counter part. This study was conducted at Dow University of health sciences and Civil Hospital Karachi (DUHS & CHK Pakistan, designed to highlight the spectrum of perforation peritonitis in the East and to improve its outcome. Methods A prospective study includes three hundred consecutive patients of perforation peritonitis studied in terms of clinical presentations, Causes, site of perforation, surgical treatment, post operative complications and mortality, at (DUHS&CHK Pakistan, from 1st September 2005 – 1st March 2008, over a period of two and half years. All patients were resuscitated underwent emergency exploratory laparotomy. On laparotomy cause of perforation peritonitis was found and controlled. Results The most common cause of perforation peritonitis noticed in our series was acid peptic disease 45%, perforated duodenal ulcer (43.6% and gastric ulcer 1.3%. followed by small bowel tuberculosis (21% and typhoid (17%. large bowel perforation due to tuberculosis 5%, malignancy 2.6% and volvulus 0.3%. Perforation due to acute appendicitis (5%. Highest number of perforations has seen in the duodenum 43.6%, ileum37.6%, and colon 8%, appendix 5%, jejunum 3.3%, and stomach 2.3%. Overall mortality was (10.6%. Conclusion The spectrum of perforation peritonitis in Pakistan continuously differs from western country. Highest number of perforations noticed in the upper part of the gastrointestinal tract as compared to the western countries where the perforations seen mostly in the distal part. Most common cause of perforation peritonitis is perforated duodenal ulcer, followed by small bowel tuberculosis and typhoid perforation. Majority of the large bowel perforations are also tubercular

Colonic perforation following endoscopic retrograde ...

African Journals Online (AJOL)

She developed severe upper abdominal pain after the ... non-surgical management of pancreatitis and associated complications, colonic perforation should be considered in patients who deteriorate ... To our knowledge this is the first case of a secure pre-operative diagnosis of colonic perforation due to to pancreatitis.

Aluminum cathode plates in zinc electrowinning cells: microstructural and failure analysis

International Nuclear Information System (INIS)

Buarzaiga, M.; Dreisinger, D.; Tromans, D.; Gonzalez, J.A.

2001-01-01

The microstructure of aluminum cathode plates used in zinc electrowinning was analyzed using optical microscopy, scanning electron microscopy, and transmission electron microscopy. Three principal phases dominated the microstructure: primary aluminum, uniformly distributed intermetallic particles, and round rosettes. The intermetallics exhibited blade shape morphology, light gray color, and were aligned in the rolling direction. The chemical composition of the intermetallic particles was consistent with FeAl 3 . Angular particles of elemental silicon were also detected. Failure characteristics of industrial cathode plates were analyzed using optical microscopy, scanning electron microscopy, energy dispersive x-ray analysis, and x-ray diffraction analysis. Three distinct corrosion zones were identified on failed plates: Zone I below the electrolyte/air interface, Zone II 0-40 mm above the electrolyte/air interface, and Zone III 40-140 mm above the electrolyte/air interface. After 24 months in service, the corrosion damage in Zones I and III was equivalent to ca. 10% reduction in plate thickness. Zone II experienced the greatest corrosion damage; the reduction in plate thickness was ca. 80%. Some plates exhibited severe thinning and perforation, which occurred preferentially near the electrical contact edge. Plates often fail in service by fracture in Zone II. (author)

Stability of La0.6Sr0.4Co0.2Fe0.8O3/Ce0.9Gd0.1O2 cathodes during sintering and solid oxide fuel cell operation

DEFF Research Database (Denmark)

Kiebach, Ragnar; Zhang, Weiwei; Zhang, Wei

2015-01-01

Degradation phenomena of La0.58Sr0.4Co0.2Fe0.8O3/Ce0.9Gd0.1O2 (LSCF/CGO) cathodes were investigated via post-mortem analyses of an experimental solid oxide fuel cell (SOFC) stack tested at 700 °C for 2000 h using advanced electron microscopy (SEM-EDS, HR-TEM-EDS) and time-of-flight secondary ion...... mass spectrometry (TOF-SIMS). Similar studies were carried out on non-tested reference cells for comparison. The analysis focused on the LSCF/CGO cathode and the CGO barrier layer, as the cathode degradation can be a major contributor to the overall degradation in this type of SOFC. SEM-EDS and TOF......-SIMS were used to investigate inter-diffusion across the barrier layer - electrolyte interface and the barrier layer - cathode interface. In addition, TOF-SIMS data were employed to investigate impurity distribution before and after testing. HR-TEM-EDS was used to investigate possible phase segregation...

Radiologic Study of Meniscus Perforations in the Temporomandibular Joint

International Nuclear Information System (INIS)

Kim, Kee Duck; Park, Chang Seo

1990-01-01

Thirty-nine patients (forty-four joints) who had been diagnosed as having meniscus perforation of the temporomandibular joint by inferior joint space arthrography and had been treated by surgical procedures were evaluated retrospectively. Information of clinical findings, arthrotomographic findings and surgical findings was collected on a standardized form and evaluated. The results were as follows: 1. On the 34 patients of 38 joints which were surgically confirmed perforation of meniscus or its attachments of the temporomandibular joint, there were 29 females and 5 males (5.8:1). The average age was 36 years (range 17 to 70). 2. The common clinical findings of group that had meniscus displacement without reduction and with perforation were pain on the affected joint and limitation of mouth opening. In the group showing meniscus displacement with reduction and with perforation the common clinical findings were pain and clicking on the affected joint. 3. 32 joints (84.2%) were arthrotomographically anterior meniscus displacement without reduction and with perforation, 6 joints (15.8%) showed anterior meniscus displacement with reduction and with perforation. 4. Joints categorized arthrotomographically as having meniscus displacement without reduction and with perforation were less likely to have full translation of the condyle in comparison with the normal or meniscus displacement with reduction and with perforation groups (p<0.05) 5. The arthrographic findings of 44 joints having meniscus perforation were compared with surgical findings, there were 6 false positive findings of meniscus perforation, the reliability of arthrographic findings of meniscus perforation was a 86.4% correlation with surgical findings. 6. On the site of perforations of 38 joints which were surgically confirmed perforation of meniscus or its attachments, twenty-three of perforations (60.5%) were in location at the junction of the meniscus and posterior attachment, fourteen (36.9%) were

Isolated jejunal perforation following blunt abdominal trauma

Directory of Open Access Journals (Sweden)

Ahmet Pergel

2012-09-01

Full Text Available Isolated perforation of the jejunum, following blunt abdominaltrauma, is extremely rare. These injuries aredifficult to diagnose because initial clinical signs are frequentlynonspecific and a delay in treatment increasesmortality and morbidity of the patients. Conventional radiogramsare often inadequate for diagnosing this subsetof trauma. For an accurate and timely diagnosis, thepossibility of bowel perforation and the need for repeatedexaminations should be kept in mind. Herein, we presenta 28-year-old man with isolated jejunal perforation followingblunt abdominal trauma.Key words: Blunt abdominal trauma, isolated jejunal perforation,early diagnosis

Perforated peptic ulcer.

Science.gov (United States)

Søreide, Kjetil; Thorsen, Kenneth; Harrison, Ewen M; Bingener, Juliane; Møller, Morten H; Ohene-Yeboah, Michael; Søreide, Jon Arne

2015-09-26

Perforated peptic ulcer is a common emergency condition worldwide, with associated mortality rates of up to 30%. A scarcity of high-quality studies about the condition limits the knowledge base for clinical decision making, but a few published randomised trials are available. Although Helicobacter pylori and use of non-steroidal anti-inflammatory drugs are common causes, demographic differences in age, sex, perforation location, and underlying causes exist between countries, and mortality rates also vary. Clinical prediction rules are used, but accuracy varies with study population. Early surgery, either by laparoscopic or open repair, and proper sepsis management are essential for good outcome. Selected patients can be managed non-operatively or with novel endoscopic approaches, but validation of such methods in trials is needed. Quality of care, sepsis care bundles, and postoperative monitoring need further assessment. Adequate trials with low risk of bias are urgently needed to provide better evidence. We summarise the evidence for perforated peptic ulcer management and identify directions for future clinical research. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Saphenous perforator flap].

Science.gov (United States)

Winkel, R; Tajsic, N; Husum, H; Schlageter, M; Hanebuth, G; Hoffmann, R

2013-04-01

Replacement of full thickness soft tissue defects in the lower leg and ankle, appropriate to the defect and following the course of blood vessels feeding the skin of a distally hinged fasciocutaneous flap most reliably based on the individual anatomy of distal perforators of the posterior tibial artery. Full thickness soft tissue defects, up to 12 cm in length and up to 8 cm in width. Sufficient vascularization of the foot required, in osteomyelitis, and when joints, fractures, implants and tendons are exposed and when a split skin graft, a local flap, a suralis perforator flap or a free flap is not indicated. For patients, in whom a 1-2 h operation is not possible; necessity of angioplasty; decollement or scars around the distal perforators of the posterior tibial artery; local infection or necrosis of soft tissues and/or bone, which cannot be totally excised. Radical debridement; flap dissection without tourniquet; microdissection; design of the flap on the skin: pivot point ~ 10 cm (6-14 cm) proximal of the tip of the medial malleolus; base ~ 5 cm in width, between the course of the saphenous nerve and of the great saphenous vein and the Achilles tendon; adipofascial pedicle up to 15 cm in length sited over the septum between soleus and flexor digitorum muscles, following the course of the saphenous nerve, with a central skin stripe, which expands into a proximal skin island; skin island is outlined similar to the defect, but larger by 1 to 2 cm, surrounded by an adipofascial border: adjustment of the planning as well as of the elevation of these flaps according to the individual position and the caliber of perforators requires in each case the search for a perforator at the estimated pivot point. Delay of transposition, if the division of more than one perforator proximal to the pivot point obviously diminishes circulation. No "tunnelling "of the pedicle; defects of skin due to the elevation of the flap are replaced by split and meshed skin grafts or temporary

Perforated marginal ulcers after laparoscopic gastric bypass.

Science.gov (United States)

Felix, Edward L; Kettelle, John; Mobley, Elijah; Swartz, Daniel

2008-10-01

Perforated marginal ulcer (PMU) after laparoscopic Roux-en-Y gastric bypass (LRYGB) is a serious complication, but its incidence and etiology have rarely been investigated. Therefore, a retrospective review of all patients undergoing LRYGB at the authors' center was conducted to determine the incidence of PMU and whether any causative factors were present. A prospectively kept database of all patients at the authors' bariatric center was retrospectively reviewed. The complete records of patients with a PMU were examined individually for accuracy and analyzed for treatment, outcome, and possible underlying causes of the marginal perforation. Between April 1999 and August 2007, 1% of the patients (35/3,430) undergoing laparoscopic gastric bypass experienced one or more perforated marginal ulcers 3 to 70 months (median, 18 months) after LRYGB. The patients with and without perforation were not significantly different in terms of mean age (37 vs 41 years), weight (286 vs 287 lb), body mass index (BMI) (46 vs 47), or female gender (89% vs 83%). Of the patients with perforations, 2 (6%) were taking steroids, 10 (29%) were receiving nonsteroidal antiinflammatory drugs (NSAIDs) at the time of the perforation, 18 (51%) were actively smoking, and 6 of the smokers also were taking NSAIDs. Eleven of the patients (31%) who perforated did not have at least one of these possible risk factors, but 4 (36%) of the 11 patients in this group had been treated after bypass for a marginal ulcer. Only 7 (20%) of the 35 patients who had laparoscopic bypass, or 7 (0.2%) in the entire group of 3,430 patients, perforated without any warning. There were no deaths, but three patients reperforated. The incidence of a marginal ulcer perforating after LRYGB was significant (>1%) and appeared to be related to smoking or the use of NSAIDs or steroids. Because only 0.2% of all patients acutely perforated without some risk factor or warning, long-term ulcer prophylaxis or treatment may be necessary

Imaging gastrointestinal perforation in pediatric blunt abdominal trauma

International Nuclear Information System (INIS)

Jamieson, D.H.; Babyn, P.S.; Pearl, R.

1996-01-01

Objective. To assess the role of imaging, in particular CT, in the early detection of GI perforation. Subjects and methods. In a 10-year period, 43 patients with surgically confirmed GI perforation were identified from hospital records; 22 of these had preoperative CT evaluation. Medical records and radiology were retrospectively reviewed and CT studies were particularly assessed for extraluminal air, free intraperitoneal fluid, bowel wall thickening, bowel wall enhancement, and bowel dilatation. During the study period an additional 12 trauma patients were identified who had CT studies demonstrating the above findings, but who had hypovolemic shock bowel or nondisrupting bowel injury without perforation evident. Results. Extraluminal air was demonstrated in 47 % of the imaged perforations. There was one false-positive extraluminal air. Perforation was confirmed in patients who had all five of the above CT findings, but this was the case for only 18 % of patients with perforation. One or more of the five specified CT findings were present in all CT studies reviewed. No false-negative CT study was performed in the study period. Conclusion. Separating nondisrupting bowel injury from perforation is diagnostically difficult; however, CT remains a good modality for assessing GI perforation in pediatric blunt trauma, but it cannot replace diligent and repeated clinical evaluation of all potential perforation victims. (orig.). With 4 figs., 1 tab

Tracking Electron Uptake from a Cathode into Shewanella Cells: Implications for Energy Acquisition from Solid-Substrate Electron Donors

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Annette R. Rowe

2018-02-01

Full Text Available While typically investigated as a microorganism capable of extracellular electron transfer to minerals or anodes, Shewanella oneidensis MR-1 can also facilitate electron flow from a cathode to terminal electron acceptors, such as fumarate or oxygen, thereby providing a model system for a process that has significant environmental and technological implications. This work demonstrates that cathodic electrons enter the electron transport chain of S. oneidensis when oxygen is used as the terminal electron acceptor. The effect of electron transport chain inhibitors suggested that a proton gradient is generated during cathode oxidation, consistent with the higher cellular ATP levels measured in cathode-respiring cells than in controls. Cathode oxidation also correlated with an increase in the cellular redox (NADH/FMNH2 pool determined with a bioluminescence assay, a proton uncoupler, and a mutant of proton-pumping NADH oxidase complex I. This work suggested that the generation of NADH/FMNH2 under cathodic conditions was linked to reverse electron flow mediated by complex I. A decrease in cathodic electron uptake was observed in various mutant strains, including those lacking the extracellular electron transfer components necessary for anodic-current generation. While no cell growth was observed under these conditions, here we show that cathode oxidation is linked to cellular energy acquisition, resulting in a quantifiable reduction in the cellular decay rate. This work highlights a potential mechanism for cell survival and/or persistence on cathodes, which might extend to environments where growth and division are severely limited.

Tracking Electron Uptake from a Cathode into Shewanella Cells: Implications for Energy Acquisition from Solid-Substrate Electron Donors

Science.gov (United States)

Rajeev, Pournami; Jain, Abhiney; Pirbadian, Sahand; Okamoto, Akihiro; Gralnick, Jeffrey A.; El-Naggar, Mohamed Y.; Nealson, Kenneth H.

2018-01-01

ABSTRACT While typically investigated as a microorganism capable of extracellular electron transfer to minerals or anodes, Shewanella oneidensis MR-1 can also facilitate electron flow from a cathode to terminal electron acceptors, such as fumarate or oxygen, thereby providing a model system for a process that has significant environmental and technological implications. This work demonstrates that cathodic electrons enter the electron transport chain of S. oneidensis when oxygen is used as the terminal electron acceptor. The effect of electron transport chain inhibitors suggested that a proton gradient is generated during cathode oxidation, consistent with the higher cellular ATP levels measured in cathode-respiring cells than in controls. Cathode oxidation also correlated with an increase in the cellular redox (NADH/FMNH2) pool determined with a bioluminescence assay, a proton uncoupler, and a mutant of proton-pumping NADH oxidase complex I. This work suggested that the generation of NADH/FMNH2 under cathodic conditions was linked to reverse electron flow mediated by complex I. A decrease in cathodic electron uptake was observed in various mutant strains, including those lacking the extracellular electron transfer components necessary for anodic-current generation. While no cell growth was observed under these conditions, here we show that cathode oxidation is linked to cellular energy acquisition, resulting in a quantifiable reduction in the cellular decay rate. This work highlights a potential mechanism for cell survival and/or persistence on cathodes, which might extend to environments where growth and division are severely limited. PMID:29487241

Lithium-ion batteries having conformal solid electrolyte layers

Science.gov (United States)

Kim, Gi-Heon; Jung, Yoon Seok

2014-05-27

Hybrid solid-liquid electrolyte lithium-ion battery devices are disclosed. Certain devices comprise anodes and cathodes conformally coated with an electron insulating and lithium ion conductive solid electrolyte layer.

Injector of solid indicator

Energy Technology Data Exchange (ETDEWEB)

Chernyshev, G.I.; Luk' yanov, E.P.; Pruslin, Y.A.; Zabrodin, P.I.

1981-04-25

The injector can be used with remote introduction of indicators into a borehole for study in an oil well of the parameters of movement of fluid currents, control of the state of the equipment, and study of the properties of the rocks. Proposed is a method of increasing the reliability of operation of the injector by stabilizing the rate of its dispersing. Introduced to the injector of a solid indicator are auxiliary brackets and a cathode made from nonmetallic electrical conducting material and reinforced at the end by an elastic bracket. The auxillary cathode is attached to the end surface of the anode and cathode.

Electrical, thermal and electrochemical properties of SmBa_1_−_xSr_xCo_2O_5_+_δ cathode materials for intermediate-temperature solid oxide fuel cells

International Nuclear Information System (INIS)

Subardi, Adi; Chen, Ching-Cheng; Cheng, Meng-Hsien; Chang, Wen-Ku; Fu, Yen-Pei

2016-01-01

The effects of Sr doping on the Ba-site of SmBaCo_2O_5_+_δ in term of structure characteristics, thermal expansion coefficients (TECs), electrical properties and electrochemical performance have been investigated as cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The TECs of SBSC-based cathodes are calculated from 19.8 − 20.5 × 10"−"6 K"−"1 in the temperature range of 100–800 °C, and the TEC values decrease with increasing Sr content. The oxygen content and the average oxidation state of cobalt increase with increasing Sr content determined by the X-ray photoelectron spectroscopy (XPS) and Thermogravimetry analysis (TGA) results. At a given temperature, the electrical conductivity values are in the order as follows: SBSC55 > SBSC73 > SBSC91. This behavior might be due to the increase in electronic hole. The electrical conductivities of SBSC55 at 600 °C are distributed in the range of 660 S/cm of p(O_2) = 0.01 atm to 1168 S/cm of p(O_2) = 0.21 atm, indicating that the cathode can endure reducing atmosphere. SBSC55 with high electrical conductivity in p(O_2) = 0.01 atm is ascribed to SBSC55 with stable double-perovskite structure at such low oxygen partial pressure. The SBSC55 cathode showed the highest power density of 304 mW/cm"2 at operating temperature of 700 °C. Based on the electrochemical properties, SBSC55 is a potential cathode for IT-SOFCs.

Electricity generation from fermented primary sludge using single-chamber air-cathode microbial fuel cells

KAUST Repository

Yang, Fei; Ren, Lijiao; Pu, Yuepu; Logan, Bruce E.

2013-01-01

Single-chamber air-cathode microbial fuel cells (MFCs) were used to generate electricity from fermented primary sludge. Fermentation (30°C, 9days) decreased total suspended solids (26.1-16.5g/L), volatile suspended solids (24.1-15.3g/L) and pH (5

Experimental perforation of tubing with a hydraulic sand jet

Energy Technology Data Exchange (ETDEWEB)

Semenov, Yu V

1970-01-01

A series of field tests has shown that perforation with a hydraulic sand jet improves the quality of well completion. The sand jet does not crack the cement sheath or the casing, and the perforations are larger and deeper than perforations formed by explosive charges. Fluid circulation during sand jet perforation can safely be stopped for at least 10 min. Water containing a surfactant can be used as a sand carrier. Sand jet perforation allows successful completion of wells cased by 2 tubing strings. Sand jet perforation can be used to clean the borehole well and to remove foreign objects from the well.

Perforated Sigmoid Diverticular Disease: a Management Protocol

Science.gov (United States)

Moin, Thajammul

2008-01-01

Background: To develop an evidence-based protocol for the management of perforated sigmoid diverticular disease. Methods: A search of the literature was undertaken. All publications pertaining to perforated sigmoid diverticular disease were analyzed and then categorized according to their level of evidence. Recommendations were then made on the basis of this. Results: Multiple case reports suggest that primary closure of perforation of sigmoid diverticula is safe in the absence of peritoneal contamination. Conclusions: A 2-stage laparoscopic approach incorporating the principles of damage limitation surgery may be a safe strategy in the management of perforated diverticular disease. PMID:18435896

Simulation of air velocity in a vertical perforated air distributor

Science.gov (United States)

Ngu, T. N. W.; Chu, C. M.; Janaun, J. A.

2016-06-01

Perforated pipes are utilized to divide a fluid flow into several smaller streams. Uniform flow distribution requirement is of great concern in engineering applications because it has significant influence on the performance of fluidic devices. For industrial applications, it is crucial to provide a uniform velocity distribution through orifices. In this research, flow distribution patterns of a closed-end multiple outlet pipe standing vertically for air delivery in the horizontal direction was simulated. Computational Fluid Dynamics (CFD), a tool of research for enhancing and understanding design was used as the simulator and the drawing software SolidWorks was used for geometry setup. The main purpose of this work is to establish the influence of size of orifices, intervals between outlets, and the length of tube in order to attain uniformity of exit flows through a multi outlet perforated tube. However, due to the gravitational effect, the compactness of paddy increases gradually from top to bottom of dryer, uniform flow pattern was aimed for top orifices and larger flow for bottom orifices.

Perforator anatomy of the ulnar forearm fasciocutaneous flap.

Science.gov (United States)

Mathy, Jon A; Moaveni, Zachary; Tan, Swee T

2012-08-01

The ulnar forearm fasciocutaneous flap (UFFF) is a favourable alternative to the radial forearm flap when thin and pliable tissue is required. The precise anatomy of the cutaneous perforators of UFFF has not been previously reported. The position of cutaneous perforators>0.5 mm was recorded while raising 52 consecutive free UFFFs in 51 patients at our Centre. Three (6%) UFFFs in two patients demonstrated direct cutaneous supply through a superficial ulnar artery, a known anatomic variance. There was no cutaneous perforator>0.5 mm in one flap. Among the remaining 48 dissections, an average of 3 (range, 1-6) cutaneous perforators were identified. Ninety-four percent of these forearms demonstrated at least one perforator>0.5 mm within 3 cm, and all had at least one perforator within 6 cm of the midpoint of the forearm. Proximal perforators were more likely to be musculo-cutaneous through the edge of flexor carpi ulnaris or flexor digitorum superficialis, while mid- to distal perforators were septo-cutaneous. UFFF skin paddle designed to overlie an area within 3 cm of the midpoint between the medial epicondyle and the pisiform is most likely to include at least one cutaneous perforator from the ulnar artery, without a need for intra-operative skin island adjustment. This novel anatomic finding and other practical generalisations are discussed to facilitate successful elevation of UFFF. Copyright © 2012 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Perforated gastric carcinoma in a young-age patient

Directory of Open Access Journals (Sweden)

Feng-Hsu Wu

2018-06-01

Full Text Available Perforation is a rare complication of gastric carcinoma, and it occurs in less than 5% of all gastric carcinoma cases and in less than 1% within all acute abdomen cases. The diagnosis of malignancy is usually not validated preoperatively. In previous reported English literature, all patients with perforated gastric cancer have the feature of old age. This feature might be able to guide the surgeon to impress the differential diagnosis of malignancy before or during the emergent operation of gastric perforation.This 32-year-old male patient suffered from sudden onset of epigastric pain. We performed emergent operation under the impression of hollow organ perforation. The postoperative pathologic report of gastric ulcer revealed gastric carcinoma. We performed second-stage operation of total gastrectomy with D2 lymphadenectomy smoothly 7 days later. As we know, this is the youngest patient having the condition of perforated gastric carcinoma reported in the literature. This case reminds us that it is possible for perforated gastric carcinoma to occur in young-age patients. Keywords: Gastric cancer, Acute abdomen, Gastric perforation

Exfoliation and reassembly of cobalt oxide nanosheets into a reversible lithium-ion battery cathode.

Science.gov (United States)

Compton, Owen C; Abouimrane, Ali; An, Zhi; Palmeri, Marc J; Brinson, L Catherine; Amine, Khalil; Nguyen, SonBinh T

2012-04-10

An exfoliation-reassembly-activation (ERA) approach to lithium-ion battery cathode fabrication is introduced, demonstrating that inactive HCoO(2) powder can be converted into a reversible Li(1-x) H(x) CoO(2) thin-film cathode. This strategy circumvents the inherent difficulties often associated with the powder processing of the layered solids typically employed as cathode materials. The delamination of HCoO(2) via a combination of chemical and mechanical exfoliation generates a highly processable aqueous dispersion of [CoO(2) ](-) nanosheets that is critical to the ERA approach. Following vacuum-assisted self-assembly to yield a thin-film cathode and ion exchange to activate this material, the generated cathodes exhibit excellent cyclability and discharge capacities approaching that of low-temperature-prepared LiCoO(2) (~83 mAh g(-1) ), with this good electrochemical performance attributable to the high degree of order in the reassembled cathode. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Deposition of Composite LSCF-SDC and SSC-SDC Cathodes by Axial-Injection Plasma Spraying

Science.gov (United States)

Harris, Jeffrey; Qureshi, Musab; Kesler, Olivera

2012-06-01

The performance of solid oxide fuel cell cathodes can be improved by increasing the number of electrochemical reaction sites, by controlling microstructures, or by using composite materials that consist of an ionic conductor and a mixed ionic and electronic conductor. LSCF (La0.6Sr0.4Co0.2Fe0.8O3-δ) and SSC (Sm0.5Sr0.5CoO3) cathodes were manufactured by axial-injection atmospheric plasma spraying, and composite cathodes were fabricated by mixing SDC (Ce0.8Sm0.2O1.9) into the feedstock powders. The plasma power was varied by changing the proportion of nitrogen in the plasma gas. The microstructures of cathodes produced with different plasma powers were characterized by scanning electron microscopy and gas permeation measurements. The deposition efficiencies of these cathodes were calculated based on the mass of the sprayed cathode. Particle surface temperatures were measured in-flight to enhance understanding of the relationship between spray parameters, microstructure, and deposition efficiency.

Enhanced stability of solid oxide fuel cells by employing a modified cathode-interlayer interface with a dense La0.6Sr0.4Co0.2Fe0.8O3-δ thin film

Science.gov (United States)

De Vero, Jeffrey C.; Develos-Bagarinao, Katherine; Kishimoto, Haruo; Ishiyama, Tomohiro; Yamaji, Katsuhiko; Horita, Teruhisa; Yokokawa, Harumi

2018-02-01

In La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode/Gd-doped ceria (GDC)/yttria-stabilized zirconia (YSZ)-electrolyte based solid oxide fuel cells (SOFCs), one of the key issues affecting performance and long-term stability is the apparent deactivation of LSCF cathode by the presence of secondary phases such as SrZrO3 at the interfaces. Herein, we report that by modifying the cathode-interlayer interface with a dense LSCF thin film, the severe cation interdiffusion is suppressed especially the fast gas or surface diffusion of Sr into adjacent GDC-interlayer/YSZ-electrolyte resulting in the significant reduction of SrZrO3 formation at the interfaces improving cell stability. In order to understand the present results, the interface chemistry is carefully considered and discussed. The results show that modification of cathode-interlayer interfaces is an important strategy for improving the lifetime of SOFCs.

PERFORATED PEPTIC ULCER: A CLINICAL ANALYSIS AND OUTCOME

OpenAIRE

Bijit

2016-01-01

BACKGROUND The incidence of perforated peptic ulcer is approximately 7-10 cases per one lakh population per year. Perforation is seen in about 7% of patients hospitalized for peptic ulcer disease. Peptic ulcer perforation, which can be gastric/duodenal perforation can be a serious life-threatening condition if not detected early and treated urgently. Peptic ulcer disease has decreased considerably worldwide with the advent of potent anti-ulcer medicines, but its complication l...

Perforated membrane-type acoustic metamaterials

International Nuclear Information System (INIS)

Langfeldt, F.; Kemsies, H.; Gleine, W.; Estorff, O. von

2017-01-01

This letter introduces a modified design of membrane-type acoustic metamaterials (MAMs) with a ring mass and a perforation so that an airflow through the membrane is enabled. Simplified analytical investigations of the perforated MAM (PMAM) indicate that the perforation introduces a second anti-resonance, where the effective surface mass density of the PMAM is much higher than the static value. The theoretical results are validated using impedance tube measurements, indicating good agreement between the theoretical predictions and the measured data. The anti-resonances yield high low-frequency sound transmission loss values with peak values over 25 dB higher than the corresponding mass-law. - Highlights: • A new membrane-type acoustic metamaterial exhibiting negative density is presented. • The metamaterial design contains a ring mass with a perforation through the membrane. • The sound transmission loss exhibits narrow-band peaks much higher than the mass-law. • The emergence of the peaks is explained using a simple theoretical model. • Impedance tube measurements are used to validate the theoretical predictions.

Perforated membrane-type acoustic metamaterials

Energy Technology Data Exchange (ETDEWEB)

Langfeldt, F., E-mail: Felix.Langfeldt@haw-hamburg.de [Department of Automotive and Aeronautical Engineering, Hamburg University of Applied Sciences, Berliner Tor 9, D-20099 Hamburg (Germany); Kemsies, H., E-mail: Hannes.Kemsies@haw-hamburg.de [Department of Automotive and Aeronautical Engineering, Hamburg University of Applied Sciences, Berliner Tor 9, D-20099 Hamburg (Germany); Gleine, W., E-mail: Wolfgang.Gleine@haw-hamburg.de [Department of Automotive and Aeronautical Engineering, Hamburg University of Applied Sciences, Berliner Tor 9, D-20099 Hamburg (Germany); Estorff, O. von, E-mail: estorff@tu-harburg.de [Institute of Modelling and Computation, Hamburg University of Technology, Denickestr. 17, D-21073 Hamburg (Germany)

2017-04-25

This letter introduces a modified design of membrane-type acoustic metamaterials (MAMs) with a ring mass and a perforation so that an airflow through the membrane is enabled. Simplified analytical investigations of the perforated MAM (PMAM) indicate that the perforation introduces a second anti-resonance, where the effective surface mass density of the PMAM is much higher than the static value. The theoretical results are validated using impedance tube measurements, indicating good agreement between the theoretical predictions and the measured data. The anti-resonances yield high low-frequency sound transmission loss values with peak values over 25 dB higher than the corresponding mass-law. - Highlights: • A new membrane-type acoustic metamaterial exhibiting negative density is presented. • The metamaterial design contains a ring mass with a perforation through the membrane. • The sound transmission loss exhibits narrow-band peaks much higher than the mass-law. • The emergence of the peaks is explained using a simple theoretical model. • Impedance tube measurements are used to validate the theoretical predictions.

Oriented cluster perforating technology and its application in horizontal wells

Directory of Open Access Journals (Sweden)

Huabin Chen

2016-11-01

Full Text Available An oriented cluster perforating technology, which integrates both advantages of cluster and oriented perforating, will help solve a series of technical complexities in horizontal well drilling. For realizing its better application in oil and gas development, a series of technologies were developed including perforator self-weight eccentricity, matching of the electronic selective module codes with the surface program control, axial centralized contact signal transmission, and post-perforation intercluster sealing insulation. In this way, the following functions could be realized, such as cable-transmission horizontal well perforator self-weight orientation, dynamic signal transmission, reliable addressing & selective perforation and post-perforation intercluster sealing. The combined perforation and bridge plug or the multi-cluster perforation can be fulfilled in one trip of perforation string. As a result, the horizontal-well oriented cluster perforating technology based on cable conveying was developed. This technology was successfully applied in unconventional gas reservoir exploitation, such as shale gas and coalbed methane, with accurate orientation, reliable selective perforation and satisfactory inter-cluster sealing. The horizontal-well oriented cluster perforating technology benefits the orientation of horizontal well drilling with a definite target and direction, which provides a powerful support for the subsequent reservoir stimulation. It also promotes the fracturing fluid to sweep the principal pay zones to the maximum extent. Moreover, it is conductive to the formation of complex fracture networks in the reservoirs, making quality and efficient development of unconventional gas reservoirs possible.

Electrochemical characterization of Pr2CuO4–Ce0.9Gd0.1O1.95 composite cathodes for solid oxide fuel cells

International Nuclear Information System (INIS)

Kolchina, L.M.; Lyskov, N.V.; Petukhov, D.I.; Mazo, G.N.

2014-01-01

Highlights: • PCO–GDC composites are studied as a cathode for SOFCs. • The rate-determined step of the overall electrode process vs. temperature was defined. • PCO–GDC33 composite gave the lowest area surface resistance of 0.41 Ω cm 2 at 700 °C. • PCO–GDC33 is preferred to use as a cathode material for IT-SOFCs. - Abstract: Pr 2 CuO 4 –Ce 0.9 Gd 0.1 O 1.95 (PCO–GDC) composites screen printed on Ce 0.9 Gd 0.1 O 1.95 (GDC) electrolyte were considered as a cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs). Phase composition, microstructure and electrochemical properties were investigated by X-ray powder diffraction (XRD), scanning electron microscopy and AC impedance spectroscopy, respectively. The oxygen reduction on porous PCO–GDC electrode applied on CGO electrolyte was studied in a symmetrical cell configuration by AC impedance spectroscopy at OCV conditions at 670–730 °C and p O 2 =10 -2 -0.21atm. The charge transfer process and the dissociation of adsorbed molecular oxygen were found to be rate-determining steps of the oxygen reduction reaction. Results reveal that both GDC addition and electrode morphology have strong influence on area specific resistance (ASR) of the electrode/electrolyte interface. The lowest ASR value of 0.41 Ω cm 2 was achieved for the composition containing 33 wt.% GDC at 700 °S in air. The data obtained allow to consider the PCO–GDC33 composite as a promising cathode material for IT-SOFCs

The value of CT in detecting pathologic bowel perforation

International Nuclear Information System (INIS)

Chang, Jong Wun; Shin, Joo Yong; Kim, Hong; Rhee, Chang Soo; Lee, Sung Moon; Joo, Yang Goo; Suh, Soo Jhi

1997-01-01

To evaluate the usefulness of CT for assessing the location and cause of pathologic gastrointestinal perforation. A retrospective analysis of abdominal CT was performed in 27 perforations of 26 patients with underlying gastrointestinal pathology. Fifteen benign and 12 malignant perforations consisted of five gastric cancers, one gastric ulcer, ten duodenal bulb ulcers. two bowel adhesions, one jejunal metastasis from lung cancer, one ileocolic Crohn's disease, one radiation colitis and six colon cancers. CT scans were evaluated for 1) diagnosis of bowel perforation, 2) assessment of the cause and site of perforation, and, in particular, differentiation between benignancy and malignancy, and 3) complications and their extent. CT easily detected varying amounts of free air or fluid collection, and infiltration or abscess formation adjacent to the main lesion, and the diagnosis of gastrointestinal perforation was therefore easy. In 11 of the 12 malignancies (92%), primary tumor was diagnosed, but detection of the site of perforation was possible in only seven cases(7/12, 58%). The 15 benign lesions revealed nonspecific CT findings, and the perforation site could be presumed in six (6/15, 40%). In one case of Crohn's disease, the primary cause was visualized. Among six colonic cancers, four pericolic abscesses and two fistulas to adjacent organs were found, but there was no evidence of diffuse peritonitis. CT was helpful to lead to optimal treatment of pathologic gastrointestinal On CT the detectability of perforation, primary benign or malignant lesion, perforation site and extent of complication was high, and this modality was therefore a useful indicator of the optimal treatment for pathologic gastrointestinal perforations.=20

Analysis of cathode materials of perovskite structure for solid oxide fuel cells, sofc s; Analisis de materiales catodicos de estructura perovskita para celdas de combustible de oxido solido, sofcs

Energy Technology Data Exchange (ETDEWEB)

Alvarado F, J.; Espino V, J.; Avalos R, L. [Universidad Michoacana de San Nicolas de Hidalgo, Facultad de Ingenieria Quimica, Santiago Tapia 403, Morelia, Michoacan (Mexico)

2015-07-01

Fuel cells directly and efficiently convert the chemical energy of a fuel into electrical energy. Of the various types of fuel cells, the solid oxide (Sofc), combine the advantages in environmentally benign energy generation with fuel flexibility. However, the need for high operating temperatures (800 - 1000 grades C) has resulted in high costs and major challenges in relation to the compatibility the cathode materials. As a result, there have been significant efforts in the development of intermediate temperature Sofc (500 - 700 grades C). A key obstacle for operation in this temperature range is the limited activity of traditional cathode materials for electrochemical reduction oxygen. In this article, the progress of recent years is discussed in cathodes for Sofc perovskite structure (ABO{sub 3}), more efficient than the traditionally used La{sub 1-x}Sr{sub x}MnO{sub 3-δ} (LSM) or (La, Sr) CoO{sub 3}. Such is the case of mixed conductors (MIEC) double perovskite structure (A A B{sub 2}O{sub 5+δ}) using different doping elements as La, Sr, Fe, Ti, Cr, Sm, Co, Cu, Pr, Nd, Gd, dy, Mn, among others, which could improve the operational performance of existing cathode materials, promoting the development of optimized intermediate temperature Sofc designs. (Author)

Duodenal perforation during percutaneous nephrolithotomy (PCNL ...

African Journals Online (AJOL)

A. Bansal

2016-06-03

Jun 3, 2016 ... Calculus;. Duodenum;. Injury;. Paediatric;. Percutaneous nephrolithotomy. Abstract. Introduction: Colonic perforations are known complications of percutaneous nephrolithotomy (PCNL). However, to the best of our knowledge, small bowel perforation has rarely been reported.. Observation: We report the ...

External perforated window Solar Screens: The effect of screen depth and perforation ratio on energy performance in extreme desert environments

KAUST Repository

Sherif, A.

2012-09-01

In hot arid desert environments, the solar radiation passing through windows increases the cooling loads and the energy consumption of buildings. Shading of windows can reduce these loads. Unlike the woven solar screens, wooden solar screens have a thickness that provides selective shading properties. Perforated wooden solar screens were traditionally used for windows shading. Developing modern types of these shading systems can lead to significant energy savings. The paper addresses the influence of changing the perforation percentage and depth of these screens on the annual energy loads, hence defining the optimum depth/perforation configurations for various window orientations. Series of experiments were performed using the EnergyPlus simulation software for a typical residential building in the Kharga Oasis, located in the Egyptian desert. A range of perforation percentages and depths were tested. Conclusions prove that external fixed deep perforated solar screens could effectively achieve energy savings up to 30% of the total energy consumption in the West and South orientations. Optimum range of depths and perforation percentages were recommended. These are: 80-90% perforation rate and 1:1 depth/opening width ratio. These lighter and deeper solar screen configurations were found to be more efficient in energy consumption in comparison with the traditional ones. © 2012 Elsevier B.V. All rights reserved.

Intestinal perforation by an ingested foreign body*

Science.gov (United States)

Nicolodi, Gabriel Cleve; Trippia, Cesar Rodrigo; Caboclo, Maria Fernanda F. S.; de Castro, Francisco Gomes; Miller, Wagner Peitl; de Lima, Raphael Rodrigues; Tazima, Leandro; Geraldo, Jamylle

2016-01-01

Objective To identify the computed tomography findings suggestive of intestinal perforation by an ingested foreign body. Materials and Methods This was a retrospective study of four cases of surgically proven intestinal perforation by a foreign body, comparing the computed tomography findings with those described in the literature. Results None of the patients reported having ingested a foreign body, all were over 60 years of age, three of the four patients used a dental prosthesis, and all of the foreign bodies were elongated and sharp. In all four patients, there were findings indicative of acute abdomen. None of the foreign bodies were identified on conventional X-rays. The computed tomography findings suggestive of perforation were thickening of the intestinal walls (in all four cases), increased density of mesenteric fat (in all four cases), identification of the foreign body passing through the intestinal wall (in three cases), and gas in the peritoneal cavity (in one case). Conclusion In cases of foreign body ingestion, intestinal perforation is more common when the foreign body is elongated and sharp. Although patients typically do not report having ingested such foreign bodies, the scenario should be suspected in elderly individuals who use dental prostheses. A computed tomography scan can detect foreign bodies, locate perforations, and guide treatment. The findings that suggest perforation are thickening of the intestinal walls, increased mesenteric fat density, and, less frequently, gas in the peritoneal cavity, often restricted to the point of perforation. PMID:27818542

Intestinal perforation by an ingested foreign body

International Nuclear Information System (INIS)

Nicolodi, Gabriel Cleve; Trippia, Cesar Rodrigo; Caboclo, Maria Fernanda F.S.; Castro, Francisco Gomes de; Miller, Wagner Peitl; Lima, Raphael Rodrigues de; Tazima, Leandro; Geraldo, Jamylle

2016-01-01

Objective: To identify the computed tomography findings suggestive of intestinal perforation by an ingested foreign body. Materials and Methods: This was a retrospective study of four cases of surgically proven intestinal perforation by a foreign body, comparing the computed tomography findings with those described in the literature. Results: None of the patients reported having ingested a foreign body, all were over 60 years of age, three of the four patients used a dental prosthesis, and all of the foreign bodies were elongated and sharp. In all four patients, there were findings indicative of acute abdomen. None of the foreign bodies were identified on conventional X-rays. The computed tomography findings suggestive of perforation were thickening of the intestinal walls (in all four cases), increased density of mesenteric fat (in all four cases), identification of the foreign body passing through the intestinal wall (in three cases), and gas in the peritoneal cavity (in one case). Conclusion: In cases of foreign body ingestion, intestinal perforation is more common when the foreign body is elongated and sharp. Although patients typically do not report having ingested such foreign bodies, the scenario should be suspected in elderly individuals who use dental prostheses. A computed tomography scan can detect foreign bodies, locate perforations, and guide treatment. The findings that suggest perforation are thickening of the intestinal walls, increased mesenteric fat density, and, less frequently, gas in the peritoneal cavity, often restricted to the point of perforation. (author)

Intestinal perforation by an ingested foreign body.

Science.gov (United States)

Nicolodi, Gabriel Cleve; Trippia, Cesar Rodrigo; Caboclo, Maria Fernanda F S; de Castro, Francisco Gomes; Miller, Wagner Peitl; de Lima, Raphael Rodrigues; Tazima, Leandro; Geraldo, Jamylle

2016-01-01

To identify the computed tomography findings suggestive of intestinal perforation by an ingested foreign body. This was a retrospective study of four cases of surgically proven intestinal perforation by a foreign body, comparing the computed tomography findings with those described in the literature. None of the patients reported having ingested a foreign body, all were over 60 years of age, three of the four patients used a dental prosthesis, and all of the foreign bodies were elongated and sharp. In all four patients, there were findings indicative of acute abdomen. None of the foreign bodies were identified on conventional X-rays. The computed tomography findings suggestive of perforation were thickening of the intestinal walls (in all four cases), increased density of mesenteric fat (in all four cases), identification of the foreign body passing through the intestinal wall (in three cases), and gas in the peritoneal cavity (in one case). In cases of foreign body ingestion, intestinal perforation is more common when the foreign body is elongated and sharp. Although patients typically do not report having ingested such foreign bodies, the scenario should be suspected in elderly individuals who use dental prostheses. A computed tomography scan can detect foreign bodies, locate perforations, and guide treatment. The findings that suggest perforation are thickening of the intestinal walls, increased mesenteric fat density, and, less frequently, gas in the peritoneal cavity, often restricted to the point of perforation.

Intestinal perforation by an ingested foreign body

Energy Technology Data Exchange (ETDEWEB)

Nicolodi, Gabriel Cleve; Trippia, Cesar Rodrigo; Caboclo, Maria Fernanda F.S.; Castro, Francisco Gomes de; Miller, Wagner Peitl; Lima, Raphael Rodrigues de; Tazima, Leandro; Geraldo, Jamylle, E-mail: gabrielnicolodi@gmail.com [Hospital Sao Vicente - Funef, Curitiba, PR (Brazil)

2016-09-15

Objective: To identify the computed tomography findings suggestive of intestinal perforation by an ingested foreign body. Materials and Methods: This was a retrospective study of four cases of surgically proven intestinal perforation by a foreign body, comparing the computed tomography findings with those described in the literature. Results: None of the patients reported having ingested a foreign body, all were over 60 years of age, three of the four patients used a dental prosthesis, and all of the foreign bodies were elongated and sharp. In all four patients, there were findings indicative of acute abdomen. None of the foreign bodies were identified on conventional X-rays. The computed tomography findings suggestive of perforation were thickening of the intestinal walls (in all four cases), increased density of mesenteric fat (in all four cases), identification of the foreign body passing through the intestinal wall (in three cases), and gas in the peritoneal cavity (in one case). Conclusion: In cases of foreign body ingestion, intestinal perforation is more common when the foreign body is elongated and sharp. Although patients typically do not report having ingested such foreign bodies, the scenario should be suspected in elderly individuals who use dental prostheses. A computed tomography scan can detect foreign bodies, locate perforations, and guide treatment. The findings that suggest perforation are thickening of the intestinal walls, increased mesenteric fat density, and, less frequently, gas in the peritoneal cavity, often restricted to the point of perforation. (author)

Intestinal perforation by an ingested foreign body

Directory of Open Access Journals (Sweden)

Gabriel Cleve Nicolodi

Full Text Available Abstract Objective: To identify the computed tomography findings suggestive of intestinal perforation by an ingested foreign body. Materials and Methods: This was a retrospective study of four cases of surgically proven intestinal perforation by a foreign body, comparing the computed tomography findings with those described in the literature. Results: None of the patients reported having ingested a foreign body, all were over 60 years of age, three of the four patients used a dental prosthesis, and all of the foreign bodies were elongated and sharp. In all four patients, there were findings indicative of acute abdomen. None of the foreign bodies were identified on conventional X-rays. The computed tomography findings suggestive of perforation were thickening of the intestinal walls (in all four cases, increased density of mesenteric fat (in all four cases, identification of the foreign body passing through the intestinal wall (in three cases, and gas in the peritoneal cavity (in one case. Conclusion: In cases of foreign body ingestion, intestinal perforation is more common when the foreign body is elongated and sharp. Although patients typically do not report having ingested such foreign bodies, the scenario should be suspected in elderly individuals who use dental prostheses. A computed tomography scan can detect foreign bodies, locate perforations, and guide treatment. The findings that suggest perforation are thickening of the intestinal walls, increased mesenteric fat density, and, less frequently, gas in the peritoneal cavity, often restricted to the point of perforation.

Neurodevelopmental outcome after neonatal perforator stroke

NARCIS (Netherlands)

Ecury-Goossen, Ginette M; van der Haer, Marit; Smit, Liesbeth S; Feijen-Roon, Monique; Lequin, Maarten; de Jonge, Rogier C J; Govaert, Paul; Dudink, Jeroen

AIM: To assess outcome after neonatal perforator stroke in the largest cohort to date. METHOD: Survivors from a cohort of children diagnosed with neonatal perforator stroke using cranial ultrasound or magnetic resonance imaging were eligible for inclusion. Recovery and Recurrence Questionnaire

The approach of in-situ doping ion conductor fabricated with the cathodic arc plasma for all-solid-state electrochromic devices

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Min-Chuan Wang

2018-01-01

Full Text Available The all-solid-state electrochromic device (ECD with the one substrate structure fabricated by the reactive dc magnetron sputtering (DCMS and in-situ doping cathodic vacuum arc plasma (CVAP technology has been developed. The electrochromic (EC layer and ion conductor layer were deposited by reactive DCMS and CVAP technology, respectively. The in-situ doping ion conductor Ta2O5 deposited by the CVAP technology has provided the better material structure for ion transportation and showed about 2 times ion conductivity than the external doping process. The all-solid-state ECD with the in-situ doping CVAP ion conductor layer has demonstrated a maximum transmittance variation (ΔT of 71% at 550 nm, and a faster switching speed. The lower production cost and higher process stability could be achieved by the application of in-situ doping CVAP technology without breaking the vacuum process. Furthermore, the ion doping process with the reuse of energy during the CVAP process is not only decreasing the process steps, but also reducing the process energy consumption.

Duodenal perforation: an unusual complication of sickle cell anemia.

Science.gov (United States)

Acıpayam, Can; Aldıç, Güliz; Akçora, Bülent; Çelikkaya, Mehmet Emin; Aşkar, Hasan; Dorum, Bayram Ali

2014-01-01

Duodenal perforation in childhood is a rare condition with a high mortality rate if not treated surgically. Primary gastroduodenal perforation is frequently associated with peptic ulcer and exhibits a positive family history. Helicobacter pylorus is the most significant agent. Secondary gastroduodenal perforation may be a finding of specific diseases, such as Crohn disease, or more rarely may be associated with diseases such as cystic fibrosis or sickle cell anemia. A 14-year-old boy presented with abdominal and back pain. The patient was operated on for acute abdomen and diagnosed with duodenal perforation. Helicobacter pylorus was negative. There was no risk factor to account for duodenal perforation other than sickle cell anemia. Surgical intervention was successful and without significant sequelae. Duodenal perforation is a rare entity described in patients with sickle cell anemia. To our knowledge, this is the first report of duodenal perforation in a patient sickle cell anemia.

The value of CT in detecting pathologic bowel perforation

Energy Technology Data Exchange (ETDEWEB)

Chang, Jong Wun; Shin, Joo Yong; Kim, Hong; Rhee, Chang Soo; Lee, Sung Moon; Joo, Yang Goo; Suh, Soo Jhi [Keimyung Univ. School of Medicine, Taegu (Korea, Republic of)

1997-10-01

To evaluate the usefulness of CT for assessing the location and cause of pathologic gastrointestinal perforation. A retrospective analysis of abdominal CT was performed in 27 perforations of 26 patients with underlying gastrointestinal pathology. Fifteen benign and 12 malignant perforations consisted of five gastric cancers, one gastric ulcer, ten duodenal bulb ulcers. two bowel adhesions, one jejunal metastasis from lung cancer, one ileocolic Crohn's disease, one radiation colitis and six colon cancers. CT scans were evaluated for (1) diagnosis of bowel perforation, (2) assessment of the cause and site of perforation, and, in particular, differentiation between benignancy and malignancy, and (3) complications and their extent. CT easily detected varying amounts of free air or fluid collection, and infiltration or abscess formation adjacent to the main lesion, and the diagnosis of gastrointestinal perforation was therefore easy. In 11 of the 12 malignancies (92%), primary tumor was diagnosed, but detection of the site of perforation was possible in only seven cases(7/12, 58%). The 15 benign lesions revealed nonspecific CT findings, and the perforation site could be presumed in six (6/15, 40%). In one case of Crohn's disease, the primary cause was visualized. Among six colonic cancers, four pericolic abscesses and two fistulas to adjacent organs were found, but there was no evidence of diffuse peritonitis. CT was helpful to lead to optimal treatment of pathologic gastrointestinal On CT the detectability of perforation, primary benign or malignant lesion, perforation site and extent of complication was high, and this modality was therefore a useful indicator of the optimal treatment for pathologic gastrointestinal perforations.=20.

Laparoscopic treatment of perforated appendicitis

Science.gov (United States)

Lin, Heng-Fu; Lai, Hong-Shiee; Lai, I-Rue

2014-01-01

The use of laparoscopy has been established in improving perioperative and postoperative outcomes for patients with simple appendicitis. Laparoscopic appendectomy is associated with less wound pain, less wound infection, a shorter hospital stay, and faster overall recovery when compared to the open appendectomy for uncomplicated cases. In the past two decades, the use of laparoscopy for the treatment of perforated appendicitis to take the advantages of minimally invasiveness has increased. This article reviewed the prevalence, approaches, safety disclaimers, perioperative and postoperative outcomes of the laparoscopic appendectomy in the treatment of patients with perforated appendicitis. Special issues including the conversion, interval appendectomy, laparoscopic approach for elderly or obese patient are also discussed to define the role of laparoscopic treatment for patients with perforated appendicitis. PMID:25339821

DETERMINATION OF THE TEMPERATURE DISTRIBUTION THE PERFORATED FINS UNDER

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Aziz7 M. Mhamuad

2015-02-01

Full Text Available This work treats the problem of heat transfer for perforated fins under natural convection. The temperature distribution is examined for an array of rectangular fins (15 fins with uniform cross-sectional area (100x270 mm embedded with various vertical body perforations that extend through the fin thickness. The patterns of perforations include 18 circular perforations (holes. Experiments were carried out in an experimental facility that was specifically design and constructed for this purpose. The heat transfer rate and the coefficient of heat transfer increases with perforation diameter increased. 

Mitigation of chromium poisoning of cathodes in solid oxide fuel cells employing CuMn1.8O4 spinel coating on metallic interconnect

Science.gov (United States)

Wang, Ruofan; Sun, Zhihao; Pal, Uday B.; Gopalan, Srikanth; Basu, Soumendra N.

2018-02-01

Chromium poisoning is one of the major reasons for cathode performance degradation in solid oxide fuel cells (SOFCs). To mitigate the effect of Cr-poisoning, a protective coating on the surface of interconnect for suppressing Cr vaporization is necessary. Among the various coating materials, Cu-Mn spinel coating is considered to be a potential candidate due to their good thermal compatibility, high stability and good electronic conductivity at high temperature. In this study, Crofer 22 H meshes with no protective coating, those with commercial CuMn2O4 spinel coating and the ones with lab-developed CuMn1.8O4 spinel coating were investigated. The lab-developed CuMn1.8O4 spinel coating were deposited on Crofer 22 H mesh by electrophoretic deposition and densified by a reduction and re-oxidation process. With these different Crofer 22 H meshes (bare, CuMn2O4-coated, and CuMn1.8O4-coated), anode-supported SOFCs with Sr-doped LaMnO3-based cathode were electrochemically tested at 800 °C for total durations of up to 288 h. Comparing the mitigating effects of the two types of Cu-Mn spinel coatings on Cr-poisoning, it was found that the performance of the denser lab-developed CuMn1.8O4 spinel coating was distinctly better, showing no degradation in the cell electrochemical performance and significantly less Cr deposition near the cathode/electrolyte interface after the test.

Synthesis and structural stability of Cr-doped Li2MnSiO4/C cathode materials by solid-state method

Science.gov (United States)

Cheng, Hong-Mei; Zhao, Shi-Xi; Wu, Xia; Zhao, Jian-Wei; Wei, Lei; Nan, Ce-Wen

2018-03-01

The crystal structure of the Li2MnSiO4 cathode material would collapse during the charge and discharge process because of that the Mn-O coordination polyhedron changed from [MnO4] into [MnO6] in the process of Mn+2 to Mn+4, but the Cr element could remain [CrO4] crystal ligand from Cr+2 to Cr+4, so Cr element substitution was used to improve the structural stability of the Li2MnSiO4 cathode material. In this work, Li2Mn1-xCrxSiO4/C nanocomposites were synthesized by solid-state method. XRD, SEM and TEM observations show that the as-prepared Li2Mn1-xCrxSiO4/C materials presents an orthorhombic crystal structure (S.G. Pmn21), the particle size of Li2Mn1-xCrxSiO4/C powder ranges from 50 to 100 nm. The XRD and XPS results indicate that Cr+2 is successfully doped into Li2MnSiO4 lattice and has well compatibility with Li2MnSiO4. The electrochemical results display that Li2Mn92.5%Cr7.5%SiO4/C exhibits significantly enhanced cycle stability and discharge capability. The initial discharge capacity of the Li2Mn92.5%Cr7.5%SiO4/C sample is 255 mAh g-1, and the discharge capacity was still about 60 mAh g-1 after 50 cycles. Furthermore, the XRD patterns, TEM images and Raman analysis reveal that the Cr doping enhances the structural stability of Li2Mn1-xCrxSiO4/C and improves the electrochemical activity of the cathode. Thus, the Li2Mn92.5%Cr7.5%SiO4/C have shown potential applications for lithium ion batteries.

Perforated peptic ulcer: How to improve outcome?

DEFF Research Database (Denmark)

Møller, Morten Hylander; Adamsen, Sven; Wøjdemann, Morten

2008-01-01

Despite the introduction of histamine H(2)-receptor antagonists, proton-pump inhibitors and the discovery of Helicobacter pylori, both the incidence of emergency surgery for perforated peptic ulcer and the mortality rate for patients undergoing surgery for peptic ulcer perforation have increased...... with an emphasis on risks that are preventable. A systematic review including randomized studies was carried out. There are a limited number of studies of patients with peptic ulcer perforation. Most of these studies are of low evidential status. Only a few randomized, controlled trials have been published...... to improve the outcome of patients with peptic ulcer perforation, sepsis needs to be factored into the existing knowledge and treatment Udgivelsesdato: 2008/8/27...

Stress and displacement analysis of a core plate, i.e. grid-perforated plate compound, modelled as an equivalent beam system

International Nuclear Information System (INIS)

Frank, R.; Engel, R.

1979-01-01

The core support plate is a very important component of the reactor pressure vessel internals. Therefore, an exact stress analysis is desired. This analysis will cause high computer costs with a detailed FEM-model because of the complexity of this compound system. In this paper, a method is suggested to solve the problem with a much cheaper beam element model. The main problem is to establish an equivalent beam system with nearly the same stiffness property as the perforated circular plate stiffened by a grid. Furthermore, the system must allow to determine the maximum stresses with sufficient accuracy. The calculation of the equivalent beam stiffness is based on the analysis of perforated plates by T. SLOT and W.J. O'DONNELL. This analysis method utilizes the concept of the equivalent solid plate. In this method, the perforated plate is replaced by a solid one which is geometrically similar to the perforated plate but has modified values of the elastic constants. The simple equivalent beam system of one half of the core support plate (symmetry) was loaded with a pressure difference and stresses and displacements were analysed. After that, these results were compared with the stress and displacement analysis of a part of the real structure. This substructure was discretized by three-dimensional 20-node brick-elements. The comparison of the results of the two models shows that the stresses and displacements, calculated with the simple beam model, are in good agreement with those of the real structure. (orig.)

Fast track pathway for perforated appendicitis.

Science.gov (United States)

Frazee, Richard; Abernathy, Stephen; Davis, Matthew; Isbell, Travis; Regner, Justin; Smith, Randall

2017-04-01

Perforated appendicitis is associated with an increased morbidity and length of stay. "Fast track" protocols have demonstrated success in shortening hospitalization without increasing morbidity for a variety of surgical processes. This study evaluates a fast track pathway for perforated appendicitis. In 2013, a treatment pathway for perforated appendicitis was adopted by the Acute Care Surgery Service for patients having surgical management of perforated appendicitis. Interval appendectomy was excluded. Patients were treated initially with intravenous antibiotics and transitioned to oral antibiotics and dismissed when medically stable and tolerating oral intake. A retrospective review of patients managed on the fast track pathway was undertaken to analyze length of stay, morbidity, and readmissions. Thirty-four males and twenty-one females with an average age of 46.8 years underwent laparoscopic appendectomy for perforated appendicitis between January 2013 and December 2014. Pre-existing comorbidities included hypertension 42%, diabetes mellitus 11%, COPD 5% and heart disease 2%. No patient had conversion to open appendectomy. Average length of stay was 2.67 days and ranged from 1 to 12 days (median 2 days). Postoperative morbidity was 20% and included abscess (6 patients), prolonged ileus (3 patients), pneumonia (1 patient), and congestive heart failure (1 patient). Five patients were readmitted for abscess (3 patients), congestive heart failure (1 patient), and pneumonia (1 patient). A fast track pathway for perforated appendicitis produced shorter length of stay and acceptable postoperative morbidity and readmission. This offers the potential for significant cost savings over current national practice patterns. Copyright © 2016 Elsevier Inc. All rights reserved.

Performance Improvement of an Inhomogeneous Cathode by Infiltration

DEFF Research Database (Denmark)

Seyed-Vakili, S. V.; Graves, Christopher R.; Babaei, A.

2017-01-01

The performance of solid oxide fuel cells (SOFCs) is considerably influenced by the microstructure and chemical composition of cathode materials. Porous La0.85Sr0.15FeO3– Ce0.9Gd0.1O2 composite electrodes were infiltrated by La0.6Sr0.4CoO3 and La0.6Sr0.4FeO3. The effects of infiltration loading...... performance of the electrodes. The electrochemical results revealed that the polarization resistance of the cathodes significantly was decreased by infiltration from 2.59 to 0.034 Ω cm2 measured at 670 °C. The best electrode performance was achieved at a calcination temperature of 770 °C. It was also found...

The Heidelberg Appendicitis Score Predicts Perforated Appendicitis in Children.

Science.gov (United States)

Boettcher, Michael; Günther, Patrick; Breil, Thomas

2017-10-01

In the future, surgical management of pediatric appendicitis might become limited to nonperforating appendicitis. Thus, it becomes increasingly important to differentiate advanced from simple appendicitis and to predict perforated appendicitis among a group of children with right-sided abdominal pain, which was the aim of this study. An institutionally approved, single-center retrospective analysis of all patients with appendectomy from January 2009 to December 2010 was conducted. All diagnostic aspects were evaluated to identify predictors and differentiators of perforated appendicitis. In 2 years, 157 children suffered from appendicitis. Perforation occurred in 47 (29.9%) of the patients. C-reactive protein (CRP) levels higher than 20 mg/dL ( P = .037) and free abdominal fluid on ultrasonography ( P = .031) are the most important features to differentiate perforated from simple appendicitis. Moreover, all children with perforation had a positive Heidelberg Appendicitis Score (HAS). A negative HAS excludes perforation in all cases (negative predictive value = 100%). Perforated appendicitis can be ruled out by the HAS. In a cohort with right-sided abdominal pain, perforation should be considered in children with high CRP levels and free fluids or abscess formation on ultrasound.

Medicolegal aspects of iatrogenic root perforations

DEFF Research Database (Denmark)

Tsesis, I; Rosen, E; Bjørndal, L

2014-01-01

AIM: To retrospectively analyze the medico-legal aspects of iatrogenic root perforations (IRP) that occurred during endodontic treatments. METHODOLOGY: A comprehensive search in a professional liability insurance database was conducted to retrospectively identify cases of IRP following root canal...... treatment (p root perforation is a complication of root canal treatment and may result in tooth extraction...... and in legal actions against the treating practitioner. Mandibular molars are more prone to medico-legal claims related to root perforations. The patient should be informed of the risks during RCT and should get information on alternative treatments and their risks and prognosis...

Investigation of the degradation of LSM-YSZ SOFC cathode by electrochemical impedance spectroscopy

DEFF Research Database (Denmark)

Torres da Silva, Iris Maura

The aim of this PhD study was to investigate degradation of the LSM-YSZ cathode of anode supported Ni-YSZ/YSZ/LSM-YSZ solid oxide fuel cells. The chosen cathode materials LSM25 and 8YSZ were investigated for their compatibility and stability, to confirm that expansion/contraction or decreasing......, at different operating conditions. An equivalent circuit was developed for the symmetrical cell, describing the processes taking place at the LSM-YSZ cathode. This equivalent circuit was applied in degradation studies, where the processes affected by degradation over time could be pinpointed. Furthermore......, it was discovered that impurities in air cause significant degradation of the cathode. Humidity was found to increase the degradation rate, but other impurities might also be present and increasing degradation. Then the anode supported Ni-YSZ/YSZ/LSM-YSZ single cells were prepared and tested. It was found...

Spontaneous ileal perforation complicating low anorectal malformation

Directory of Open Access Journals (Sweden)

TiJesuni Olatunji

2015-01-01

Full Text Available Anorectal malformation is a common anomaly in neonates. Although colorectal perforations have been reported as a complication, ileal perforation is rarely encountered. This is a report of a 2-day-old boy presenting with a low anorectal malformation, complicated with ileal perforation, necessitating laparotomy and ileal repair. Anoplasty was done for the low anomaly. Early presentation and prompt treatment of anorectal malformations is important to prevent such potential life threatening complication.

Premixed Combustion of Coconut Oil on Perforated Burner

Directory of Open Access Journals (Sweden)

I.K.G. Wirawan

2013-10-01

Full Text Available Coconut oil premixed combustion behavior has been studied experimentally on perforated burner with equivalence ratio (φ varied from very lean until very rich. The results showed that burning of glycerol needs large number of air so that the laminar burning velocity (SL is the highest at very lean mixture and the flame is in the form of individual Bunsen flame on each of the perforated plate hole. As φ is increased the  SL decreases and the secondary Bunsen flame with open tip occurs from φ =0.54 at the downstream of perforated flame. The perforated flame disappears at φ = 0.66 while the secondary Bunsen flame still exist with SL increases following that of hexadecane flame trend and then extinct when the equivalence ratio reaches one or more. Surrounding ambient air intervention makes SL decreases, shifts lower flammability limit into richer mixture, and performs triple and cellular flames. The glycerol diffusion flame radiation burned fatty acids that perform cellular islands on perforated hole.  Without glycerol, laminar flame velocity becomes higher and more stable as perforated flame at higher φ. At rich mixture the Bunsen flame becomes unstable and performs petal cellular around the cone flame front. Keywords: cellular flame; glycerol; perforated flame;secondary Bunsen flame with open tip; triple flame

Microvascular anatomy of the cerebellar parafloccular perforating space.

Science.gov (United States)

Sosa, Pablo; Dujovny, Manuel; Onyekachi, Ibe; Sockwell, Noressia; Cremaschi, Fabián; Savastano, Luis E

2016-02-01

The cerebellopontine angle is a common site for tumor growth and vascular pathologies requiring surgical manipulations that jeopardize cranial nerve integrity and cerebellar and brainstem perfusion. To date, a detailed study of vessels perforating the cisternal surface of the middle cerebellar peduncle-namely, the paraflocculus or parafloccular perforating space-has yet to be published. In this report, the perforating vessels of the anterior inferior cerebellar artery (AICA) in the parafloccular space, or on the cisternal surface of the middle cerebellar peduncle, are described to elucidate their relevance pertaining to microsurgery and the different pathologies that occur at the cerebellopontine angle. Fourteen cadaveric cerebellopontine cisterns (CPCs) were studied. Anatomical dissections and analysis of the perforating arteries of the AICA and posterior inferior cerebellar artery at the parafloccular space were recorded using direct visualization by surgical microscope, optical histology, and scanning electron microscope. A comprehensive review of the English-language and Spanish-language literature was also performed, and findings related to anatomy, histology, physiology, neurology, neuroradiology, microsurgery, and endovascular surgery pertaining to the cerebellar flocculus or parafloccular spaces are summarized. A total of 298 perforating arteries were found in the dissected specimens, with a minimum of 15 to a maximum of 26 vessels per parafloccular perforating space. The average outer diameter of the cisternal portion of the perforating arteries was 0.11 ± 0.042 mm (mean ± SD) and the average length was 2.84 ± 1.2 mm. Detailed schematics and the surgical anatomy of the perforating vessels at the CPC and their clinical relevance are reported. The parafloccular space is a key entry point for many perforating vessels toward the middle cerebellar peduncle and lateral brainstem, and it must be respected and protected during surgical approaches to the

A Novel Perforator Flap Training Model Using a Chicken Leg.

Science.gov (United States)

Cifuentes, Ignacio J; Yañez, Ricardo A; Salisbury, Maria C; Rodriguez, José R; Varas, Julian E; Dagnino, Bruno L

2016-04-01

Living animal models are frequently used for perforator flap dissection training, but no ex vivo models have been described. The aim of this study is to present a novel nonliving model for perforator flap training based on a constant perforator in the chicken leg. A total of 15 chicken legs were used in this study. Anatomical dissection of the perforator was performed after its identification using ink injection, and in four of these specimens a perforator-based flap was raised. The anatomical dissection revealed a constant intramuscular perforator with a median length of 5.7 cm. Median proximal and distal vessel diameters were 0.93 and 0.4 mm, respectively. The median dissection time was 77.5 minutes. This study introduces a novel, affordable, and reproducible model for the intramuscular dissection of a perforator-based flap using an ex vivo animal model. Its consistent perforator and appropriate-sized vessels make it useful for training.

Esophageal perforation

Science.gov (United States)

... esophagus into the space around the lungs. Collapsed lung. X-rays taken after you drink a non-harmful dye can help pinpoint the location of the perforation. You may also have chest CT scan look for an abscess in the chest or esophageal cancer.

[Iatrogen perforation of the rectum after colon radiography].

Science.gov (United States)

Eggum, R; Kressner, U; Haffner, J

1998-05-10

Perforation of the rectum following barium enema is relatively rare, occurring in 1 of 3,000 procedures. Colorectal perforation is a serious condition and early diagnosis is of paramount importance in order to avoid any delay in treating the patient. Direct suture of the perforation, lavage, presacral drainage and stomia are the preferred methods of primary surgical treatment.

The Effect of Humidity and Oxygen Partial Pressure on LSM–YSZ Cathode

DEFF Research Database (Denmark)

Knöfel, Christina; Chen, Ming; Mogensen, Mogens Bjerg

2011-01-01

Two series of anode supported solid oxide fuel cells (SOFC) were prepared, one with a composite cathode layer of lanthanum strontium manganite (LSM) and yttria stabilized zirconia (YSZ) on top and the other further has a LSM current collector layer on top. The fuel cells were heat treated at 1...... of manganese concentration and strontium enrichment on the surface of the materials. Formation of monoclinic zirconia and zirconate phases was also observed. These results give a closer insight into possible degradation mechanisms of SOFC composite cathode materials in dependence of humidity and oxygen partial...

Perforated duodenal ulcer: an unusual complication of gastroenteritis.

OpenAIRE

Wilson, J M; Darby, C R

1990-01-01

A 7 year old boy was admitted to hospital with gastroenteritis, which was complicated by an acute perforated duodenal ulcer. After oversewing of the perforation he made an uncomplicated recovery. Peptic ulceration is under-diagnosed in childhood and this leads to delay in diagnosis and appropriate management. Ulceration is associated with severe illness and viral infections, but perforation is rare.

Iatrogen perforation of the rectum following barium enema

International Nuclear Information System (INIS)

Eggum, R.; Kressner, U.; Haffner, J.

1998-01-01

Perforation of the rectum following barium enema is relatively rare, occurring in 1 of 3,000 procedures. Colorectal perforation is a serious condition and early diagnosis is of paramount importance in order to avoid any delay in treating the patient. Direct suture of the perforation, lavage, presacral drainage and stomia are the preferred methods of primary surgical treatment. 10 refs., 1 fig

Highly efficient and robust cathode materials for low-temperature solid oxide fuel cells: PrBa0.5Sr0.5Co(2-x)Fe(x)O(5+δ).

Science.gov (United States)

Choi, Sihyuk; Yoo, Seonyoung; Kim, Jiyoun; Park, Seonhye; Jun, Areum; Sengodan, Sivaprakash; Kim, Junyoung; Shin, Jeeyoung; Jeong, Hu Young; Choi, YongMan; Kim, Guntae; Liu, Meilin

2013-01-01

Solid oxide fuel cells (SOFC) are the cleanest, most efficient, and cost-effective option for direct conversion to electricity of a wide variety of fuels. While significant progress has been made in anode materials with enhanced tolerance to coking and contaminant poisoning, cathodic polarization still contributes considerably to energy loss, more so at lower operating temperatures. Here we report a synergistic effect of co-doping in a cation-ordered double-perovskite material, PrBa0.5Sr0.5Co(2-x)Fe(x)O(5+δ), which has created pore channels that dramatically enhance oxygen ion diffusion and surface oxygen exchange while maintaining excellent compatibility and stability under operating conditions. Test cells based on these cathode materials demonstrate peak power densities ~2.2 W cm(-2) at 600°C, representing an important step toward commercially viable SOFC technologies.

Highly efficient and robust cathode materials for low-temperature solid oxide fuel cells: PrBa0.5Sr0.5Co2−xFexO5+δ

Science.gov (United States)

Choi, Sihyuk; Yoo, Seonyoung; Kim, Jiyoun; Park, Seonhye; Jun, Areum; Sengodan, Sivaprakash; Kim, Junyoung; Shin, Jeeyoung; Jeong, Hu Young; Choi, YongMan; Kim, Guntae; Liu, Meilin

2013-01-01

Solid oxide fuel cells (SOFC) are the cleanest, most efficient, and cost-effective option for direct conversion to electricity of a wide variety of fuels. While significant progress has been made in anode materials with enhanced tolerance to coking and contaminant poisoning, cathodic polarization still contributes considerably to energy loss, more so at lower operating temperatures. Here we report a synergistic effect of co-doping in a cation-ordered double-perovskite material, PrBa0.5Sr0.5Co2−xFexO5+δ, which has created pore channels that dramatically enhance oxygen ion diffusion and surface oxygen exchange while maintaining excellent compatibility and stability under operating conditions. Test cells based on these cathode materials demonstrate peak power densities ~2.2 W cm−2 at 600°C, representing an important step toward commercially viable SOFC technologies. PMID:23945630

Parasacral Perforator Flaps for Reconstruction of Sacral Pressure Sores.

Science.gov (United States)

Lin, Chin-Ta; Chen, Shih-Yi; Chen, Shyi-Gen; Tzeng, Yuan-Sheng; Chang, Shun-Cheng

2015-07-01

Despite advances in reconstruction techniques, pressure sores continue to present a challenge to the plastic surgeon. The parasacral perforator flap is a reliable flap that preserves the entire contralateral side as a future donor site. On the ipsilateral side, the gluteal muscle itself is preserved and all flaps based on the inferior gluteal artery are still possible. We present our experience of using parasacral perforator flaps in reconstructing sacral defects. Between August 2004 and January 2013, 19 patients with sacral defects were included in this study. All the patients had undergone surgical reconstruction of sacral defects with a parasacral perforator flap. The patients' sex, age, cause of sacral defect, flap size, flap type, numbers of perforators used, rotation angle, postoperative complications, and hospital stay were recorded. There were 19 parasacral perforator flaps in this series. All flaps survived uneventfully except for 1 parasacral perforator flap, which failed because of methicillin-resistant Staphylococcus aureus infection. The overall flap survival rate was 95% (18/19). The mean follow-up period was 17.3 months (range, 2-24 months). The average length of hospital stay was 20.7 days (range, 9-48 days). No flap surgery-related mortality was found. Also, there was no recurrence of sacral pressure sores or infected pilonidal cysts during the follow-up period. Perforator-based flaps have become popular in modern reconstructive surgery because of low donor-site morbidity and good preservation of muscle. Parasacral perforator flaps are durable and reliable in reconstructing sacral defects. We recommend the parasacral perforator flap as a good choice for reconstructing sacral defects.

First Principles Studies of Perovskites for Intermediate Temperature Solid Oxide Fuel Cell Cathodes

KAUST Repository

Salawu, Omotayo Akande

2017-05-15

Fundamental advances in cathode materials are key to lowering the operating temperature of solid oxide fuel cells (SOFCs). Detailed understanding of the structural, electronic and defect formation characteristics are essential for rational design of cathode materials. In this thesis we employ first principles methods to study La(Mn/Co)O3 and LnBaCo2O5+δ (Ln = Pr, Gd; δ = 0.5, 1) as cathode for SOFCs. Specifically, factors affecting the O vacancy formation and migration are investigated. We demonstrate that for LaMnO3 the anisotropy effects often neglected at high operating temperatures become relevant when the temperature is lowered. We show that this fact has consequences for the material properties and can be further enhanced by strain and Sr doping. Tensile strain promotes both the O vacancy formation and migration in pristine and Sr doped LaMnO3, while Sr doping enhances the O vacancy formation but not the migration. The effect of A-site hole doping (Mg2+, Ca2+ or Ba2+) on the electronic and magnetic properties as well as the O vacancy formation and migration in LaCoO3 are studied. All three dopants are found to facilitate O vacancy formation. Substitution of La3+ with Ba2+/Mg2+ yields the lowest O vacancy formation energy for low/intermediate spin Co, implying that not only the structure, but also the spin state of Co is a key parameter. Only for low spin Co the ionic radius is correlated with the O migration barrier. Enhanced migration for intermediate spin Co is ascribed to the availability of additional space at the transition state. For LnBaCo2O5+δ we compare the O vacancy formation in GdBaCo2O5.5 (Pmmm symmetry) and GdBaCo2O6 (P4/mmm symmetry), and the influence of Sr doping. The O vacancy formation energy is demonstrated to be smaller in the already O deficient compound. This relation is maintained under Sr doping. It turns out that Sr doping can be utilized to significantly enhance the O vacancy formation in both compounds. The observed trends are

Acquired perforating dermatosis in a patient with chronic renal failure.

Science.gov (United States)

Fernandes, Karen de Almeida Pinto; Lima, Lourenço de Azevedo; Guedes, Juliana Chaves Ruiz; Lima, Ricardo Barbosa; D'Acri, Antônio Macedo; Martins, Carlos José

2016-01-01

Perforating dermatoses are a group of skin diseases characterized by transepidermal elimination of dermal material. The disease is divided into two groups: the primary group and the secondary group. The classical or primary perforating dermatoses are subdivided into four types according to the eliminated dermal materials: Kyrle disease, perforating reactive collagenosis, elastosis perforans serpiginosa, and perforating folliculitis. The secondary form is known as acquired perforating dermatosis. The term was proposed in 1989 by Rapini to designate the perforating dermatoses affecting adult patients with systemic disease, regardless of the dermal materials eliminated. This report describes a case of the disease with elimination of collagen and elastic fibers in a patient with chronic renal failure.

Use of pulsed neutron logging to evaluate perforation washing

International Nuclear Information System (INIS)

Dimon, C.A.

1986-01-01

This invention relates to the use of pulsed neutron logging techniques before and after perforation washing operations are performed to evaluate the degree of success of the perforation washing operations. Well logging operations of a type designed to respond to the difference between a formation immediately behind the well sheath and voids in the formation are performed both before and after the perforation washing operation. differences between the two resulting logs are then indicative of voids created by perforation washing. In a preferred embodiment, pulsed neutron logging is used as the logging technique, while a weighted brine having a high absorption cross section to pulsed neutrons is used as the perforation washing fluid

Idiopathic gastric perforation in an asplenic infant | Olsen | African ...

African Journals Online (AJOL)

Introduction: The cause of idiopathic gastric perforations in neonates remains unknown. Perforations of the abdominal oesophagus, stomach and duodenum in infants and children are the rarest type of intestinal perforations. There are 21 reported cases of an idiopathic gastric rupture in nonneonates. Case Report: A ...

Semi-solid electrode cell having a porous current collector and methods of manufacture

Science.gov (United States)

Chiang, Yet-Ming; Carter, William Craig; Cross, III, James C.; Bazzarella, Ricardo; Ota, Naoki

2017-11-21

An electrochemical cell includes an anode, a semi-solid cathode, and a separator disposed therebetween. The semi-solid cathode includes a porous current collector and a suspension of an active material and a conductive material disposed in a non-aqueous liquid electrolyte. The porous current collector is at least partially disposed within the suspension such that the suspension substantially encapsulates the porous current collector.

Air plasma spray processing and electrochemical characterization of SOFC composite cathodes

Science.gov (United States)

White, B. D.; Kesler, O.; Rose, Lars

Air plasma spraying has been used to produce porous composite cathodes containing (La 0.8Sr 0.2) 0.98MnO 3- y (LSM) and yttria-stabilized zirconia (YSZ) for use in solid oxide fuel cells (SOFCs). Preliminary investigations focused on determining the range of plasma conditions under which each of the individual materials could be successfully deposited. A range of conditions was thereby determined that was suitable for the deposition of a composite cathode from pre-mixed LSM and YSZ powders. A number of composite cathodes were produced using different combinations of parameter values within the identified range according to a Uniform Design experimental grid. Coatings were then characterized for composition and microstructure using EDX and SEM. As a result of these tests, combinations of input parameter values were identified that are best suited to the production of coatings with microstructures appropriate for use in SOFC composite cathodes. A selection of coatings representative of the types of observed microstructures were then subjected to electrochemical testing to evaluate the performance of these cathodes. From these tests, it was found that, in general, the coatings that appeared to have the most suitable microstructures also had the highest electrochemical performances, provided that the deposition efficiency of both phases was sufficiently high.

Air plasma spray processing and electrochemical characterization of SOFC composite cathodes

Energy Technology Data Exchange (ETDEWEB)

White, B.D. [Department of Mechanical Engineering, The University of British Columbia, 2054-6250 Applied Sciences Lane, Vancouver, British Columbia (Canada); Kesler, O. [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario (Canada); Rose, Lars [Department of Materials Engineering, The University of British Columbia, 309-6350 Stores Road, Vancouver, British Columbia (Canada); National Research Council (Canada)

2008-03-15

Air plasma spraying has been used to produce porous composite cathodes containing (La{sub 0.8}Sr{sub 0.2}){sub 0.98}MnO{sub 3-y} (LSM) and yttria-stabilized zirconia (YSZ) for use in solid oxide fuel cells (SOFCs). Preliminary investigations focused on determining the range of plasma conditions under which each of the individual materials could be successfully deposited. A range of conditions was thereby determined that was suitable for the deposition of a composite cathode from pre-mixed LSM and YSZ powders. A number of composite cathodes were produced using different combinations of parameter values within the identified range according to a Uniform Design experimental grid. Coatings were then characterized for composition and microstructure using EDX and SEM. As a result of these tests, combinations of input parameter values were identified that are best suited to the production of coatings with microstructures appropriate for use in SOFC composite cathodes. A selection of coatings representative of the types of observed microstructures were then subjected to electrochemical testing to evaluate the performance of these cathodes. From these tests, it was found that, in general, the coatings that appeared to have the most suitable microstructures also had the highest electrochemical performances, provided that the deposition efficiency of both phases was sufficiently high. (author)

CORRELATION BETWEEN TYMPANIC MEMBRANE PERFORATION AND HEARING LOSS

Directory of Open Access Journals (Sweden)

Lidija RISTOVSKA

2016-04-01

Full Text Available Introduction: Perforation of the tympanic membrane primarily results from middle ear infections, trauma or iatrogenic causes. The perforation causes conductive hearing loss by reducing the surface area available for sound transmission to the ossicular chain. Objective: The objective was to analyze the characteristics of tympanic membrane perforations in relation to hearing loss and to determine the type and degree of hearing loss. Materials and methods: We analyzed audiometric, otoscopic findings and medical reports of 218 patients, 114 males (52.3% and 104 females (47.7%, aged 9 to 75 years (mean age of 47.9 years, examined during the period of November 2012 to October 2015. For statistical data analysis we used Chi-square test with level of significance p<0.05. Results: Most of the patients had unilateral perforations (89% with right ear predominance and involvement of two quadrants of pars tensa (37.2%. Mean air-bone gap was 23.9 dB. The largest air-bone gap was at frequency of 250 Hz. Most of the patients (73.1% had mixed hearing loss (p=0.032, and average hearing thresholds from 21 to 40 dB. Conclusion: Mean air-bone gap is largest at the lower frequencies, and decreases as frequency increases. Size of the perforation has effect on hearing loss. Mean air-bone gap increases with increasing size of the perforation. There is no big difference between the mean air-bone gap in posterior versus anterior perforations.

Gallbladder perforation complicating typhoid fever: report of two cases.

Science.gov (United States)

Gali, B M; Ali, N; Agbese, G O; Duna, V D; Dawha, S D; Ismai, G I; Mohammed, M

2011-01-01

Gallbladder perforation (GBP) is rare and as a complication of typhoid fever is extremely rare. We present two consecutive patients with GBP diagnosed incidentally at laparotomy. Information on the management of two patients with gallbladder perforation seen at Federal Medical Centre Azare in June and October 2008 was extracted from their case records. The two patients were both males aged 13 years and 16 years. They both presented with high fever of more than 2 weeks duration; and abdominal pain and distension. Both patients had features of generalised peritonitis. Pre-operative diagnoses of typhoid enteric perforation were made based on a positive Widal test. Intra-operative findings however, were that of bile peritonitis and gallbladder perforation. Both had cholecystectomy. Culture of the bile aspirate yielded Salmonella typhi. Gallbladder perforation secondary to typhoid fever should be considered as a differential diagnosis in patients with suspected typhoid enteric perforation in typhoid fever endemic region.

Porous La_0.6Sr_0.4CoO_3-δ thin film cathodes for large area micro solid oxide fuel cell power generators

DEFF Research Database (Denmark)

Garbayo, A.; Esposito, Vincenzo; Sanna, Simone

2014-01-01

Porous La0.6Sr0.4CoO3-δ thin films were fabricated by pulsed laser deposition for being used as a cathode for micro solid oxide fuel cell applications as MEMS power generators. Symmetrical La0.6Sr0.4CoO3-δ/ yttria-stabilized zirconia/La0.6Sr0.4CoO3-δ free-standing membranes were fabricated using ...

An X-band high-impedance relativistic klystron amplifier with an annular explosive cathode

Energy Technology Data Exchange (ETDEWEB)

Zhu, Danni; Zhang, Jun, E-mail: zhangjun@nudt.edu.cn; Zhong, Huihuang; Qi, Zumin [College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2015-11-15

The feasibility of employing an annular beam instead of a solid one in the X-band high-impedance relativistic klystron amplifier (RKA) is investigated in theory and simulation. Small-signal theory analysis indicates that the optimum bunching distance, fundamental current modulation depth, beam-coupling coefficient, and beam-loaded quality factor of annular beams are all larger than the corresponding parameters of solid beams at the same beam voltage and current. An annular beam RKA and a solid beam RKA with almost the same geometric parameters are compared in particle-in-cell simulation. Output microwave power of 100 MW, gain of 50 dB, and power conversion efficiency of 42% are obtained in an annular beam RKA. The annular beam needs a 15% lower uniform guiding magnetic field than the solid beam. Our investigations demonstrate that we are able to use a simple annular explosive cathode immersed in a lower uniform magnetic field instead of a solid thermionic cathode in a complicated partially shielding magnetic field for designing high-impedance RKA, which avoids high temperature requirement, complicated electron-optical system, large area convergence, high current density, and emission uniformity for the solid beam. An equivalent method for the annular beam and the solid beam on bunching features is proposed and agrees with the simulation. The annular beam has the primary advantages over the solid beam that it can employ the immersing uniform magnetic field avoiding the complicated shielding magnetic field system and needs a lower optimum guiding field due to the smaller space charge effect.

Hyperbilirubinemia as a predictor for appendiceal perforation

DEFF Research Database (Denmark)

Burcharth, J; Pommergaard, H C; Rosenberg, J

2013-01-01

Delayed or wrong diagnosis in patients with appendicitis can result in perforation and consequently increased morbidity and mortality. Serum bilirubin may be a useful marker for appendiceal perforation. The purpose of this systematic review was to evaluate studies investigating elevated serum...

Sigmoid Colonic Perforation with Faecal Peritonitis due to Faecaloma

Directory of Open Access Journals (Sweden)

Ibrahim Khalil

2014-09-01

Full Text Available Colon perforation is an uncommon event usually caused by malignancy, diverticular disease, amoebic colitis, steroid therapy, trauma and ulcerative colitis, but stercoral perforation is very rare. Severe chronic constipation is considered to be the main causative factor in development of stercoral perforation of colon. Sometimes it can also produce catastrophic complications like colonic obstruction, faecal peritonitis and septicaemia. We report a rare case of sigmoid colonic perforation with faecal peritonitis and pneumoperitonium due to faecaloma which was diagnosed after exploratory laparotomy.

Peptic ulcer perforation

African Journals Online (AJOL)

FinePrint

2015-06-01

Jun 1, 2015 ... Peptic ulcer perforation is one of the surgical complications of peptic ulcer ... Treatment can be operative or non-operative followed by proton .... chronic gastritis without evidence of ... inhibits pancreatic bicarbonate secretion.

(La{sub 0.74}Bi{sub 0.10}Sr{sub 0.16})MnO{sub 3-{delta}}-(Bi{sub 2}O{sub 3}){sub 0.7}(Er{sub 2}O{sub 3}){sub 0.} {sub 3} composite cathodes for intermediate temperature solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Li, Junliang; Wang, Shaorong; Wang, Zhengrong; Liu, Renzhu; Wen, Tinglian; Wen, Zhaoyin [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

2008-05-01

(La{sub 0.74}Bi{sub 0.10}Sr{sub 0.16})MnO{sub 3-{delta}} (LBSM)-(Bi{sub 2}O{sub 3}){sub 0.7}(Er{sub 2}O{sub 3}){sub 0.3}(ESB) composite cathodes were fabricated for intermediate-temperature solid oxide fuel cells with Sc-stabilized zirconia as the electrolyte. The performance of these cathodes was investigated at temperatures below 750 C by AC impedance spectroscopy and the results indicated that LBSM-ESB had a better performance than traditional composite electrodes such as LSM-GDC and LSM-YSZ. At 750 C, the lowest interfacial polarization resistance was only 0.11 {omega} cm{sup 2} for the LBSM-ESB cathode, 0.49 {omega} cm{sup 2} for the LSM-GDC cathode, and 1.31 {omega} cm{sup 2} for the LSM-YSZ cathode. The performance of the cathode was improved gradually by increasing the ESB content, and the performance was optimal when the amounts of LBSM and ESB were equal in composite cathodes. This study shows that the sintering temperature of the cathode affected performance, and the optimum sintering temperature for LBSM-ESB was 900 C. (author)

Perforated peptic ulcer following gastric bypass for obesity.

Science.gov (United States)

Macgregor, A M; Pickens, N E; Thoburn, E K

1999-03-01

Peptic ulcer in the excluded segment of a gastric bypass performed in the management of morbid obesity has only rarely been reported in the literature. The purpose of this study is to review our experience with the condition in a series of 4300 patients who underwent gastric-restrictive surgery between 1978 and 1997. Eleven patients presented with acute perforation of a peptic ulcer in the excluded gastric segment. Nine ulcers were duodenal, one was gastric, and one patient had both gastric and duodenal perforations. The time between primary gastric-restrictive surgery and ulcer perforation varied from 20 days to 12 years. All patients presented with upper abdominal pain. The classical radiological sign of perforated peptic ulcer, free air under the diaphragm, did not occur in any patient. Nine patients were initially treated by primary closure of the perforation with subsequent definitive ulcer therapy by vagotomy, pyloroplasty, or gastrectomy. One case, initially treated elsewhere, was managed by placement of a Malecot catheter through the duodenal perforation, gastrostomy, and peritoneal drainage. One recent case remains symptom-free on H2 blockers after simple closure. There was no mortality. Six cases were previously reported in the literature with a 33 per cent mortality rate.

Stercoral perforation in a 17-year old.

LENUS (Irish Health Repository)

McHugh, S

2012-02-01

INTRODUCTION: Stercoral perforation is a rare cause of perforation. This is the first reported case where a partial eating disorder (ED) is the primary causative differential. CASE PRESENTATION: We present the case of a 17-year-old girl who presented to her local Emergency Department with a 24-h history of left-sided abdominal pain. She subsequently deteriorated and a computed tomography scan of her abdomen showed gross distension of the large bowel with a sigmoid perforation. She underwent total colectomy with end ileostomy. Histology reported stercoral perforation but normal bowel ganglia. While an inpatient she was reviewed by the Psychiatric team who were concerned she was suffering from a partial ED. CONCLUSION: This case highlights the importance of a multidisciplinary approach in optimally treating patients such as these. Aggressive medical management with involvement of a psychiatric team and dietetics addresses any underlying causative psychiatric issues and helps prevent recurrence.

Stercoral perforation in a 17-year old.

LENUS (Irish Health Repository)

McHugh, S

2009-04-02

INTRODUCTION: Stercoral perforation is a rare cause of perforation. This is the first reported case where a partial eating disorder (ED) is the primary causative differential. CASE PRESENTATION: We present the case of a 17-year-old girl who presented to her local Emergency Department with a 24-h history of left-sided abdominal pain. She subsequently deteriorated and a computed tomography scan of her abdomen showed gross distension of the large bowel with a sigmoid perforation. She underwent total colectomy with end ileostomy. Histology reported stercoral perforation but normal bowel ganglia. While an inpatient she was reviewed by the Psychiatric team who were concerned she was suffering from a partial ED. CONCLUSION: This case highlights the importance of a multidisciplinary approach in optimally treating patients such as these. Aggressive medical management with involvement of a psychiatric team and dietetics addresses any underlying causative psychiatric issues and helps prevent recurrence.

Multielectronic conduction in La1-xSrxGa1/2Mn1/2O3-δ as solid oxide fuel cell cathode

Science.gov (United States)

Iguchi, E.; Hashimoto, Y.; Kurumada, M.; Munakata, F.

2003-08-01

Four-probe dc conductivities, capacitances, and thermopower have been measured in the temperature range of 80-1123 K for La1-xSrxGa1/2Mn1/2O3-δ, which is a desirable cathode material for lanthanum-gallate electrolytes of solid oxide fuel cells. The dc conductivities in the specimens (0.1⩽x⩽0.3) are insensitive to x but the thermopower is very sensitive to x, although the x=0 specimen exhibits a somewhat different conduction behavior. At T500 K, the band conduction dominates the electronic transports. The ionic conduction due to O2- migration seems difficult to contribute directly to the dc conduction even at high temperature.

Characteristics of scandate-impregnated cathodes with sub-micron scandia-doped matrices

International Nuclear Information System (INIS)

Yuan Haiqing; Gu Xin; Pan Kexin; Wang Yiman; Liu Wei; Zhang Ke; Wang Jinshu; Zhou Meiling; Li Ji

2005-01-01

We describe in this paper scandate-impregnated cathodes with sub-micron scandia-doped tungsten matrices having an improved uniformity of the Sc distribution. The scandia-doped tungsten powders were made by both liquid-solid doping and liquid-liquid doping methods on the basis of previous research. By improving pressing, sintering and impregnating procedures, we have obtained scandate-impregnated cathodes with a good uniformity of the Sc 2 O 3 - distribution. The porosity of the sub-micron structure matrix and content of impregnants inside the matrix are similar to those of conventionally impregnated cathodes. Space charge limited current densities of more than 30 A/cm 2 at 850 deg. C b have been obtained in a reproducible way. The current density continuously increases during the first 2000 h life test at 950 deg. C b with a dc load of 2 A/cm 2 and are stable for at least 3000 h

Colonic carcinoma with multiple small bowel perforations mimicking intestinal obstruction

Directory of Open Access Journals (Sweden)

Khanna Rahul

2006-09-01

Full Text Available Abstract Background Carcinoma of the colon may present with perforation proximal to the site of malignancy. Caecum is the commonest site of perforation if the ileocecal valve is patent and the jejunal and ileal perforations are very rare. Case presentation A 35 year male presented with intestinal obstruction. Emergency laparotomy revealed carcinoma of the transverse colon with multiple pinpoint perforations along antimesenteric border of ileum, which were wrapped with omentum, and no peritoneal contamination was present. Extended right hemicolectomy with jejunocolic anastomosis was done. Patient made uneventful recovery in postoperative period and was treated with adjuvant chemotherapy. Conclusion Patients with colonic carcinoma and incompetent ileocecal valve may present with intestinal perforation. Increased intraluminal pressure and closed loop obstruction may lead to ischemia and perforation of the small bowel.

Energy Analysis of Solar Collector With perforated Absorber Plate

Directory of Open Access Journals (Sweden)

Ammar A. Farhan

2017-09-01

Full Text Available The thermal performance of three solar collectors with 3, 6 mm and without perforation absorber plate was assessed experimentally. The experimental tests were implemented in Baghdad during the January and February 2017. Five values of airflow rates range between 0.01 – 0.1 m3/s were used through the test with a constant airflow rate during the test day. The variation of the following parameters air temperature difference, useful energy, absorber plate temperature, and collector efficiency was recorded every 15 minutes. The experimental data reports that the increases the number of absorber plate perforations with a small diameter is more efficient rather than increasing the hole diameter of the absorber plate with decreasing the perforation numbers. Maximum air temperature difference throughout the solar collector with 3, 6 mm perforations and without perforations are 17, 15, and 12 oC, respectively. Also, it can be concluded that the energy gained from the solar collector with 3 mm perforation absorber plate is 28.2 % more than the energy gained from solar collector without holes per day for 0.1 m3/s airflow rate. The maximum values of the thermal performance curves are 0.67, 0.64, and 0.56 for the solar collector with 3, 6 mm, and without perforations, respectively.

Arrangement for formation perforating and fracturing

Energy Technology Data Exchange (ETDEWEB)

Belyaev, B M; Vitsenii, E M; Zheltov, Yu P; Nikolaev, S I

1962-03-06

An arrangement for perforating and hydraulic fracturing, to be lowered on a wire line, consists of a chamber with a shaped charge, a head and a nozzle. This arrangement enables carrying out, simultaneously, the operations of perforating and fracturing. The device may be equipped with separate sections with shaped charges and a powder chamber in which powder charges are placed, designed to be ignited in sequence by slow- acting electric igniters. For controlling the gas pressure and strengthening the arrangement in the zone of perforation, the device is equipped with rubber seals which release the ring elements under pressure of explosive gas. Between the walls of the casing and the rubber seals is an annular space through the gas escapes.

Thermodynamic Evaluation of LSCF Cathode Stability and Tolerance towards Gas Impurities

DEFF Research Database (Denmark)

Zhang, Weiwei; Chen, Ming; Hendriksen, Peter Vang

2014-01-01

for intermediate-temperature solid oxide fuel cells. Despite its technological importance, the phase stability of the LSCF perovskite has not yet been fully mapped out and may be critical for the use of the materials during long-term operation. For cells with LSCF or LSCF/CGO (CGO: gadolinia doped ceria) cathodes......Strontium and iron co-doped lanthanum cobaltites (La1-xSrxCo1-yFeyO3-δ, LSCF) show good oxygen ion and electronic conductivity and fast oxygen surface exchange kinetics at temperatures between 600 and 800 °C, and is considered today one of the most promising class of cathode materials...

Intraabdominal contamination after gallbladder perforation during laparoscopic cholecystectomy and its complications.

Science.gov (United States)

Kimura, T; Goto, H; Takeuchi, Y; Yoshida, M; Kobayashi, T; Sakuramachi, S; Harada, Y

1996-09-01

Gallbladder perforation often occurs during laparoscopic cholecystectomy. The frequency and causes of gallbladder perforation as well as the relevant clinical background factors were investigated in 110 patients undergoing laparoscopic cholecystectomy. We also evaluated intraperitoneal contamination by bacteria and gallstones at the time of gallbladder perforation and investigated whether perforation caused early or late postoperative complications. Intraoperative gallbladder perforation occurred in 29 of the 110 patients (26.3%). It was caused by injury with an electric knife during dissection of the gallbladder bed, injury during gallbladder retraction with grasping forceps, injury during gallbladder extraction from the abdomen, and slippage of cystic duct clips (potentially causing bile and stone spillage). Perforation was more frequent in patients with positive bile cultures and in those with pigment stones (p gallbladder perforation is sometimes unavoidable during laparoscopic cholecystectomy, the risk of severe complications appears to be minimized by early closure of perforation, retrieval of as many of the spilled stones as possible, and intraperitoneal lavage.

MRI of perforated gall bladder

International Nuclear Information System (INIS)

Sood, B.; Jain, M.; Khandelwal, N.; Singh, P.; Suri, S.

2002-01-01

Gall bladder perforation is a dreaded complication of acute cholecystitis that, if not diagnosed early in the course, might have a poor prognosis. Both CT and ultrasonography have been used until now extensively for the diagnosis of acute cholecystitis, but diagnosis of perforation is always difficult. Magnetic resonance, by its superior soft tissue resolution and multiplanar capability, is a better modality and should fare better than ultrasonography and CT, as demonstrated in our case. Magnetic resonance imaging demonstrates the wall of the gall bladder and defects to a much better advantage and more convincingly. In addition, MR colangiopancreatography images demonstrate the biliary tree better than other modalities. We suggest that in the case of acute cholecystitis, if perforation is suspected and CT and ultrasonography are not conclusive, MR should be the modality of choice. It can be used as a first line of investigation; however, it might not be cost-effective. Copyright (2002) Blackwell Science Pty Ltd

La0.6Sr0.4Co0.2Fe0.8O3-δ nanofiber cathode for intermediate-temperature solid oxide fuel cells by water-based sol-gel electrospinning: Synthesis and electrochemical behaviour

DEFF Research Database (Denmark)

Enrico, Anna; Zhang, Wenjing (Angela); Traulsen, Marie Lund

2018-01-01

Water-based sol-gel electrospinning is employed to manufacture perovskite oxide La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) nanofiber cathodes for intermediate-temperature solid oxide fuel cells. LSCF fibrous scaffolds are synthesized through electrospinning of a sol-gel solution employing water as the only...

Neutron scattering study on cathode LiMn2O4 and solid electrolyte 5(Li2O)(P2O5)

International Nuclear Information System (INIS)

Kartini, E.; Putra, Teguh P.; Jahya, A. K.; Insani, A.; Adams, S.

2014-01-01

Neutron scattering is very important technique in order to investigate the energy storage materials such as lithium-ion battery. The unique advantages, neutron can see the light atoms such as Hydrogen, Lithium, and Oxygen, where those elements are negligible by other corresponding X-ray method. On the other hand, the energy storage materials, such as lithium ion battery is very important for the application in the electric vehicles, electronic devices or home appliances. The battery contains electrodes (anode and cathode), and the electrolyte materials. There are many challenging to improve the existing lithium ion battery materials, in order to increase their life time, cyclic ability and also its stability. One of the most scientific challenging is to investigate the crystal structure of both electrode and electrolyte, such as cathodes LiCoO 2 , LiMn 2 O 4 and LiFePO 4 , and solid electrolyte Li 3 PO 4 . Since all those battery materials contain Lithium ions and Oxygen, the used of neutron scattering techniques to study their structure and related properties are very important and indispensable. This article will review some works of investigating electrodes and electrolytes, LiMn 2 O 4 and 5(Li 2 O)(P 2 O 5 ), by using a high resolution powder diffraction (HRPD) at the multipurpose research reactor, RSG-Sywabessy of the National Nuclear Energy Agency (BATAN), Indonesia

Microstructural studies on degradation of interface between LSM–YSZ cathode and YSZ electrolyte in SOFCs

DEFF Research Database (Denmark)

Liu, Yi-Lin; Hagen, Anke; Barfod, Rasmus

2009-01-01

The changes in the cathode/electrolyte interface microstructure have been studied on anode-supported technological solid oxide fuel cells (SOFCs) that were subjected to long-term (1500 h) testing at 750 °C under high electrical loading (a current density of 0.75 A/cm2). These cells exhibit...... different cathode degradation rates depending on, among others, the composition of the cathode gas, being significantly smaller in oxygen than in air. FE-SEM and high resolution analytical TEM were applied for characterization of the interface on a submicron- and nano-scale. The interface degradation has...... to decrease further due to the more pronounced formation of insulating zirconate phases that are present locally and preferably in LSM/YSZ electrolyte contact areas. The effects of the cathode gas on the interface degradation are discussed considering the change of oxygen activity at the interface, possible...

Cobalt-free perovskite Pr_0_._5Sr_0_._5Fe_1_−_xCu_xO_3_−_δ (PSFC) as a cathode material for intermediate temperature solid oxide fuel cells

International Nuclear Information System (INIS)

Moura, Caroline G.; Grilo, João Paulo de F.; Macedo, Daniel A.; Cesário, Moisés R.; Fagg, Duncan Paul; Nascimento, Rubens M.

2016-01-01

PSFC (Pr_0_._5Sr_0_._5Fe_1_−_xCu_xO_3_−_δ) is a new perovskite-type oxide that has gained considerable attention as cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs), due to its high mixed ionic-electronic conductivity below 800 °C. In this work, PSFC (Pr_0_._5Sr_0_._5Fe_1_−_xCu_xO_3_−_δ, x = 0.2 and 0.4) powders were synthesized by the citrate method and structurally characterized by X-ray diffractometry. Screen-printed cathodes were sintered at 1050 °C and electrochemically characterized by impedance spectroscopy at 600–800 °C in pure oxygen. The area specific resistances (ASR) of the Pr_0_._5Sr_0_._5Fe_0_._8Cu_0_._2O_3_−_δ material are shown to be competitive with typical values reported for cobalt-based cathodes in the measured temperature range, while, importantly, offering a significantly lower activation energy, 0.62 eV. The thermal expansion coefficients of these Co-free cathodes are in the range of 13–15 × 10"−"6 °C"−"1, in a temperature range 200–650 °C, demonstrating a good thermal compatibility with gadolinia doped ceria (CGO) electrolytes. - Highlights: • Cobalt-free Pr_0_._5Sr_0_._5Fe_1_−_xCu_xO_3_−_δ (PSFC) cathodes successfully prepared by the citrate method. • PSFC cathodes are thermally compatible with CGO electrolytes. • Pr_0_._5Sr_0_._5Fe_0_._8Cu_0_._2O_3_−_δ presents competitive area specific resistances of low activation energy, 0.62 eV.

Optimization of the process of steel strip perforation and nickel platting for the purpose of elimination of trichloroethylene from the cleaning process of perforated steel strip

Directory of Open Access Journals (Sweden)

Petrović Aleksandra B.

2009-01-01

Full Text Available In the production of pocket type electrodes for Ni-Cd batteries perforation of proper steel strips and then nickel platting of perforated steel strips were made. In the nickel platting process, the organic solvent, trichloroethylene, has previously been used for cleaning. Due to the carcinogenic nature of trichloroethylene and the many operations previously required during cleaning, it was considered to do cleaning of perforated steel strips without use of the mentioned organic solvent. In the purpose of elimination of trichloroethylene from the cleaning process of perforated steel strips, the tests of perforation of steel strips with use of oils of different viscosity were made. It was shown that there was no dysfunction during the work of the perforation plants, meaning there was no additional heating of the strips, deterring of the steel filings, nor excessive wearing of the perforation apparatus. The perforation percent was the same irrelevant of the viscosity of the used oil. Before being perforated using the oils with different viscosity, the nickel platting steel strips were cleaned in different degreasers (based on NaOH as well as on KOH. It was shown that efficient cleaning without the use of trichloroethylene is possible with the use of oil with smaller viscosity in the perforated steel strips process and the degreaser based on KOH in the cleaning process, before nickel platting. It also appeared that the alkali degreaser based on KOH was more efficient, bath corrections were made less often and the working period of the baths was longer, which all in summary means less quantity of chemicals needed for degreasing of perforated steel strips.

Novel Non-Vacuum Fabrication of Solid State Lithium Ion Battery Components

Energy Technology Data Exchange (ETDEWEB)

Oladeji, I. [Planar Energy Devices, Inc.; Wood, D. L. [ORNL; Wood, III, D. L.

2012-10-19

The purpose of this Cooperative Research and Development Agreement (CRADA) between Oak Ridge National Laboratory (ORNL) and Planar Energy Devices, Inc. was to develop large-scale electroless deposition and photonic annealing processes associated with making all-solid-state lithium ion battery cathode and electrolyte layers. However, technical and processing difficulties encountered in 2011 resulted in the focus of the CRADA being redirected solely to annealing of the cathode thin films. In addition, Planar Energy Devices de-emphasized the importance of annealing of the solid-state electrolytes within the scope of the project, but materials characterization of stabilized electrolyte layers was still of interest. All-solid-state lithium ion batteries are important to automotive and stationary energy storage applications because they would eliminate the problems associated with the safety of the liquid electrolyte in conventional lithium ion batteries. However, all-solid-state batteries are currently produced using expensive, energy consuming vacuum methods suited for small electrode sizes. Transition metal oxide cathode and solid-state electrolyte layers currently require about 30-60 minutes at 700-800°C vacuum processing conditions. Photonic annealing requires only milliseconds of exposure time at high temperature and a total of <1 min of cumulative processing time. As a result, these processing techniques are revolutionary and highly disruptive to the existing lithium ion battery supply chain. The current methods of producing all-solid-state lithium ion batteries are only suited for small-scale, low-power cells and involve high-temperature vacuum techniques. Stabilized LiNixMnyCozAl1-x-y-zO2 (NMCA) nanoparticle films were deposited onto stainless steel substrates using Planar Energy Devices’ streaming process for electroless electrochemical deposition (SPEED). Since successful SPEED trials were demonstrated by Planar Energy Devices with NMCA prior to 2010, this

Electrodeposition of americium on a liquid cadmium cathode from a molten salt bath

International Nuclear Information System (INIS)

Laplace, A.; Lacquement, J.; Maillard, C.; Donner, L.

2004-01-01

A high-activity experiment involving the electrode position of americium on a liquid cadmium cathode from a LiCl-KCl eutectic with about 3 g of AmO 2 was conducted in a shielded cell in the ATALANTE complex. After describing the electrolyzer and the experimental conditions, the authors discuss the preparation of the LiCl-KCl-AmCl 3 solution and briefly review its electrochemical properties. It was clearly confirmed that Am(III) reduction on an inert solid cathode occurs in two steps forming Am(II) before Am(0), whereas only one reduction step was observed on liquid cadmium. The main results of this study concern americium electrode position on the liquid cadmium cathode (recovery yields, current densities, problems encountered). The solvent properties of cadmium for actinide/lanthanide separation are discussed. (authors)

Analysis of cathode geometry to minimize cathode erosion in direct current microplasma jet

Energy Technology Data Exchange (ETDEWEB)

Causa, Federica [Dipartimento di Scienze dell' Ambiente, della Sicurezza, del Territorio, degli Alimenti e della Salute, Universita degli studi di Messina, 98122 Messina (Italy); Ghezzi, Francesco; Caniello, Roberto; Grosso, Giovanni [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA-CNR Association, Via R. Cozzi 53, 20125 Milano (Italy); Dellasega, David [Istituto di Fisica del Plasma, Consiglio Nazionale delle Ricerche, EURATOM-ENEA-CNR Association, Via R. Cozzi 53, 20125 Milano (Italy); Dipartimento di Energia, Politecnico di Milano, Via Ponzio 34/3, 20133 Milano (Italy)

2012-12-15

Microplasma jets are now widely used for deposition, etching, and materials processing. The present study focuses on the investigation of the influence of cathode geometry on deposition quality, for microplasma jet deposition systems in low vacuum. The interest here is understanding the influence of hydrogen on sputtering and/or evaporation of the electrodes. Samples obtained with two cathode geometries with tapered and rectangular cross-sections have been investigated experimentally by scanning electron microscopy and energy dispersion X-ray spectroscopy. Samples obtained with a tapered-geometry cathode present heavy contamination, demonstrating cathode erosion, while samples obtained with a rectangular-cross-section cathode are free from contamination. These experimental characteristics were explained by modelling results showing a larger radial component of the electric field at the cathode inner wall of the tapered cathode. As a result, ion acceleration is larger, explaining the observed cathode erosion in this case. Results from the present investigation also show that the ratio of radial to axial field components is larger for the rectangular geometry case, thus, qualitatively explaining the presence of micro-hollow cathode discharge over a wide range of currents observed in this case. In the light of the above findings, the rectangular cathode geometry is considered to be more effective to achieve cleaner deposition.

Fouling Resilient Perforated Feed Spacers for Membrane Filtration

KAUST Repository

Kerdi, Sarah

2018-04-24

The improvement of feed spacers with optimal geometry remains a key challenge for spiral-wound membrane systems in water treatment due to their impact on the hydrodynamic performance and fouling development. In this work, novel spacer designs are proposed by intrinsically modifying cylindrical filaments through perforations. Three symmetric perforated spacers (1-Hole, 2-Hole, and 3-Hole) were in-house 3D-printed and experimentally evaluated in terms of permeate flux, feed channel pressure drop and membrane fouling. Spacer performance is characterized and compared with standard no perforated (0-Hole) design under constant feed pressure and constant feed flow rate. Perforations in the spacer filaments resulted in significantly lowering the net pressure drop across the spacer filled channel. The 3-Hole spacer was found to have the lowest pressure drop (50% - 61%) compared to 0-Hole spacer for various average flow velocities. Regarding permeate flux production, the 0-Hole spacer produced 5.7 L.m-2.h-1 and 6.6 L.m-2.h-1 steady state flux for constant pressure and constant feed flow rate, respectively. The 1-Hole spacer was found to be the most efficient among the perforated spacers with 75% and 23% increase in permeate production at constant pressure and constant feed flow, respectively. Furthermore, membrane surface of 1-Hole spacer was found to be cleanest in terms of fouling, contributing to maintain higher permeate flux production. Hydrodynamic understanding of these perforated spacers is also quantified by performing Direct Numerical Simulation (DNS). The performance enhancement of these perforated spacers is attributed to the formation of micro-jets in the spacer cell that aided in producing enough unsteadiness/turbulence to clean the membrane surface and mitigate fouling phenomena. In the case of 1-Hole spacer, the unsteadiness intensity at the outlet of micro-jets and the shear stress fluctuations created inside the cells are higher than those observed with

Fouling resilient perforated feed spacers for membrane filtration.

Science.gov (United States)

Kerdi, Sarah; Qamar, Adnan; Vrouwenvelder, Johannes S; Ghaffour, Noreddine

2018-04-24

The improvement of feed spacers with optimal geometry remains a key challenge for spiral-wound membrane systems in water treatment due to their impact on the hydrodynamic performance and fouling development. In this work, novel spacer designs are proposed by intrinsically modifying cylindrical filaments through perforations. Three symmetric perforated spacers (1-Hole, 2-Hole, and 3-Hole) were in-house 3D-printed and experimentally evaluated in terms of permeate flux, feed channel pressure drop and membrane fouling. Spacer performance is characterized and compared with standard no perforated (0-Hole) design under constant feed pressure and constant feed flow rate. Perforations in the spacer filaments resulted in significantly lowering the net pressure drop across the spacer filled channel. The 3-Hole spacer was found to have the lowest pressure drop (50%-61%) compared to 0-Hole spacer for various average flow velocities. Regarding permeate flux production, the 0-Hole spacer produced 5.7 L m -2 .h -1 and 6.6 L m -2 .h -1 steady state flux for constant pressure and constant feed flow rate, respectively. The 1-Hole spacer was found to be the most efficient among the perforated spacers with 75% and 23% increase in permeate production at constant pressure and constant feed flow, respectively. Furthermore, membrane surface of 1-Hole spacer was found to be cleanest in terms of fouling, contributing to maintain higher permeate flux production. Hydrodynamic understanding of these perforated spacers is also quantified by performing Direct Numerical Simulation (DNS). The performance enhancement of these perforated spacers is attributed to the formation of micro-jets in the spacer cell that aided in producing enough unsteadiness/turbulence to clean the membrane surface and mitigate fouling phenomena. In the case of 1-Hole spacer, the unsteadiness intensity at the outlet of micro-jets and the shear stress fluctuations created inside the cells are higher than those

Nasal Septum Perforation due to Methamphetamine abuse

Directory of Open Access Journals (Sweden)

Mehdi Bakhshaee

2012-07-01

Full Text Available Introduction: Spontaneous Perforation of the nasal septum is an uncommon condition. Nasal inhalation of substances such as cocaine has long been linked to this Perforation. Case Report: This report describes the case of a 46-year-old woman who was addicted to methamphetamine and who presented with perforation of the nasal septum.This is the first reported case of nasal septal necrosis linked to nasal inhalation of methamphetamine. Conclusions: Patient history and assurance regardingillegal drug consumption and abuse is a key point for fast and accurate diagnosis. The pathophysiology of drug-induced sinunasal disease and a review of the literature are also presented.

Spectrum of perforation peritonitis in India--review of 504 consecutive cases.

Science.gov (United States)

Jhobta, Rajender Singh; Attri, Ashok Kumar; Kaushik, Robin; Sharma, Rajeev; Jhobta, Anupam

2006-09-05

Perforation peritonitis is the most common surgical emergency in India. The spectrum of etiology of perforation in Tropical countries continues to be different from its Western counterpart. The objective of the study was to highlight the spectrum of perforation peritonitis as encountered by us at Government Medical College and Hospital (GMCH), Chandigarh. Five hundred and four consecutive cases of perforation peritonitis over a period of five years were reviewed in terms of clinical presentation, operative findings and postoperative course retrospectively at GMCH, Chandigarh. The most common cause of perforation in our series was perforated duodenal ulcer (289 cases) followed by appendicitis (59 cases), gastrointestinal perforation due to blunt trauma abdomen (45 cases), typhoid fever (41 cases) and tuberculosis (20 cases). Despite delay in seeking medical treatment (53%), the overall mortality (10%) was favourably comparable with other published series though the overall morbidity (50%) was unusually high. In contrast to western literature, where lower gastrointestinal tract perforations predominate, upper gastrointestinal tract perforations constitute the majority of cases in India. The increasing incidence of post-traumatic gastro-enteric injuries may be due to an increase in high speed motor vehicle accidents which warrant early recognition and prompt treatment to avoid serious complications and death.

Spectrum of perforation peritonitis in India-review of 504 consecutive cases

Directory of Open Access Journals (Sweden)

Sharma Rajeev

2006-09-01

Full Text Available Abstract Background/objective Perforation peritonitis is the most common surgical emergency in India. The spectrum of etiology of perforation in Tropical countries continues to be different from its Western counterpart. The objective of the study was to highlight the spectrum of perforation peritonitis as encountered by us at Government Medical College and Hospital (GMCH, Chandigarh. Methods Five hundred and four consecutive cases of perforation peritonitis over a period of five years were reviewed in terms of clinical presentation, operative findings and postoperative course retrospectively at GMCH, Chandigarh. Results The most common cause of perforation in our series was perforated duodenal ulcer (289 cases followed by appendicitis (59 cases, gastrointestinal perforation due to blunt trauma abdomen (45 cases, typhoid fever (41 cases and tuberculosis (20 cases. Despite delay in seeking medical treatment (53%, the overall mortality (10% was favourably comparable with other published series though the overall morbidity (50% was unusually high. Conclusion In contrast to western literature, where lower gastrointestinal tract perforations predominate, upper gastrointestinal tract perforations constitute the majority of cases in India. The increasing incidence of post-traumatic gastro-enteric injuries may be due to an increase in high speed motor vehicle accidents which warrant early recognition and prompt treatment to avoid serious complications and death.

Contact lens rehabilitation following repaired corneal perforations

Science.gov (United States)

Titiyal, Jeewan S; Sinha, Rajesh; Sharma, Namrata; Sreenivas, V; Vajpayee, Rasik B

2006-01-01

Background Visual outcome following repair of post-traumatic corneal perforation may not be optimal due to presence of irregular keratometric astigmatism. We performed a study to evaluate and compare rigid gas permeable contact lens and spectacles in visual rehabilitation following perforating corneal injuries. Method Eyes that had undergone repair for corneal perforating injuries with or without lens aspiration were fitted rigid gas permeable contact lenses. The fitting pattern and the improvement in visual acuity by contact lens over spectacle correction were noted. Results Forty eyes of 40 patients that had undergone surgical repair of posttraumatic corneal perforations were fitted rigid gas permeable contact lenses for visual rehabilitation. Twenty-four eyes (60%) required aphakic contact lenses. The best corrected visual acuity (BCVA) of ≥ 6/18 in the snellen's acuity chart was seen in 10 (25%) eyes with spectacle correction and 37 (92.5%) eyes with the use of contact lens (p < 0.001). The best-corrected visual acuity with spectacles was 0.20 ± 0.13 while the same with contact lens was 0.58 ± 0.26. All the patients showed an improvement of ≥ 2 lines over spectacles in the snellen's acuity chart with contact lens. Conclusion Rigid gas permeable contact lenses are better means of rehabilitation in eyes that have an irregular cornea due to scars caused by perforating corneal injuries. PMID:16536877

Frequency of wound infection in non-perforated appendicitis with use of single dose perforative antibiotics

International Nuclear Information System (INIS)

Ali, K.; Latif, H.; Ahmad, S.

2015-01-01

Antibiotics are used both pre and post-operatively in acute appendicitis for preventing wound infection. It has been observed that the routine use of post-operative antibiotics is not necessary in cases of non-perforated appendicitis as only prophylactic antibiotics are sufficient to prevent wound infection. The aim of this study was to see the frequency of wound infection in non-perforated appendicitis with single dose preoperative antibiotics only. Method: This observational study was conducted at the Department of Surgery, Ayub Medical College, Abbottabad from May to November 2014. A total of 121 patients with non-perforated appendicitis were included in the study. Only single dose preoperative antibiotics were used. The patients were followed for wound infection till 8th post-operative day. Results: 121 patients, 56(46.28%) male and 65(53.72%) female were included in the study. The mean age of patients was 27.41 ± 7.12 years with an age range of 18 to 45 years. In the entire series, 7(5.78%) patients developed wound infection. The infection was minor which settled with conservative therapy. Prophylactic antibiotics were found efficacious in 114(94.21%) patients. There was no significant association between wound infection and age and gender. Conclusion: Single dose preoperative antibiotics were found effective in controlling post-operative wound infection without the need of extending the antibiotics to post-operative period in cases of non-perforated appendicitis. (author)

Effect of low temperature in-situ sintering on the impedance and the performance of intermediate temperature solid oxide fuel cell cathodes

DEFF Research Database (Denmark)

Nielsen, Jimmi; Hjalmarsson, Per; Hansen, Martin Hangaard

2014-01-01

The effect of in-situ sintering temperature and time on the electronic conductivity, impedance and performance of IT-SOFC cathodes were studied. The studied cathodes were for comparison (La0.6Sr0.4)0.99CoO3 (LSC), (La0.6Sr0.4)0.99CoO3:Ce0.9Gd0.1O1.95 (LSC:CGO), La0.58Sr0.4Co0.2Fe0.8O3 (LSCF) and La......0.58Sr0.4Co0.2Fe0.8O3:Ce0.9Gd0.1O1.95 (LSCF:CGO). The LSCF-based cathodes showed poor sintering capabilities compared to the LSC-based cathodes in the studied temperature range of 650–950 °C. The poor necking between individual LSCF grains lower the electronic conductivity. Furthermore, poor cathode....../electrolyte adhesion was seen as an additional high frequency impedance arc, which gradually disappeared as the LSCF cathodes were sintered at increasing temperature. Effects on the impedance shape from poor cathode grain connectivity was shown through impedance simulations to result in a possible increase in the high...

Preoperative chest x-ray findings in peptic ulcer perforation

Energy Technology Data Exchange (ETDEWEB)

Kim, T. H.; Kim, S. W.; Lim, J. S.; Kim, Y. J. [Kyungpook National University School of Medicine, Taegu (Korea, Republic of)

1981-12-15

This study was carried out to analyze the distribution of age, sex, chief complaint, physical examination and findings of chest x-ray films before operation in 59 cases of peptic ulcer perforation. The ratio of male to female was 1.7 : 1 and incidence of the ulcer perforation was most common in 5th decades. Thirty five among 59 cases showed pleural effusion, segmental atelectasis and pneumonic infiltration on chest x-ray film. Twenty nine among 50 cases of duodenal ulcer perforation and 6 of 9 cases of stomach ulcer perforation showed positive chest x-ray findings. No relationship was found between fever and preoperative chest x-ray findings.

Preoperative chest x-ray findings in peptic ulcer perforation

International Nuclear Information System (INIS)

Kim, T. H.; Kim, S. W.; Lim, J. S.; Kim, Y. J.

1981-01-01

This study was carried out to analyze the distribution of age, sex, chief complaint, physical examination and findings of chest x-ray films before operation in 59 cases of peptic ulcer perforation. The ratio of male to female was 1.7 : 1 and incidence of the ulcer perforation was most common in 5th decades. Thirty five among 59 cases showed pleural effusion, segmental atelectasis and pneumonic infiltration on chest x-ray film. Twenty nine among 50 cases of duodenal ulcer perforation and 6 of 9 cases of stomach ulcer perforation showed positive chest x-ray findings. No relationship was found between fever and preoperative chest x-ray findings

Depression cathode structure for cathode ray tubes having surface smoothness and method for producing same

International Nuclear Information System (INIS)

Rychlewski, T.V.

1984-01-01

Depression cathode structures for cathode ray tubes are produced by dispensing liquid cathode material into the depression of a metallic supporting substrate, removing excess cathode material by passing a doctor blade across the substrate surface and over the depression, and drying the cathode layer to a substantially immobile state. The cathode layer may optionally be further shaped prior to substantially complete drying thereof

Primary Closure versus Gastric Resection for Perforated Gastric

African Journals Online (AJOL)

Perforated gastric ulcer is one of the most life‑threatening complications of peptic ulcer disease with high .... tubes were removed and oral nutrition resumed. The .... surgical approach for perforated gastric cancer: One‑stage vs. two‑stage ...

(La{sub 0.74}Bi{sub 0.10}Sr{sub 0.16})MnO{sub 3-{delta}}-Ce{sub 0.8}Gd{sub 0.2}O{sub 2-{delta}} cathodes fabricated by ion-impregnating method for intermediate-temperature solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Li, Junliang; Wang, Shaorong; Wang, Zhenrong; Liu, Renzhu; Ye, Xiaofeng; Sun, Xiufu; Wen, Tinglian; Wen, Zhaoyin [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

2009-03-15

Porous composite cathodes were fabricated by impregnating (La{sub 0.74}Bi{sub 0.10}Sr{sub 0.16})MnO{sub 3-{delta}} (LBSM) electronic conducting structure with the ionic conducting Ce{sub 0.8}Gd{sub 0.2}O{sub 2-{delta}} (GDC) phase. The ion impregnation of the GDC phase significantly enhanced the electrocatalytic activity of the LBSM electrodes for the O{sub 2} reduction reactions, and the ion-impregnated LBSM-GDC composite cathodes showed excellent performance. At 700 C, the value of the cathode polarization resistance (Rc) was only 0.097 {omega} cm{sup 2} for an ion-impregnated LBSM-GDC cathode, and the performance was gradually improved by increasing the loading of the impregnated GDC. For the performance testing of single cells, the maximum power density was 1036 mW cm{sup -2} at 700 C for a cell with the LBSM-GDC cathode. The results demonstrated the unique combination of the LBSM electronic conducting structure with high ionic conducting GDC phase was a valid method to improve the electrode performance, and the ion-impregnated LBSM-GDC was a promising composite cathode material for the intermediate-temperature solid oxide fuel cells. (author)

Study on Dynamic Response of Downhole Tools under Perforation Impact Load

Directory of Open Access Journals (Sweden)

Liu Jun

2017-01-01

Full Text Available A model of a multibody system is established to investigate the dynamic response of an oil tube-shock absorber-perforating gun system in downhole perforation-test joint operation. In the model, the oil tube and perforating gun are modeled as elastic rods and the shock absorber is modeled as single particle system with damping and a spring. Two force continuity conditions are used to simulate the interactions among the three components. The perforation impact load is determined by an experiment of underwater explosion of perforating bullets. Using the model, the effects of charge quantity of perforating bullet, the number of shock absorbers, and the length of oil tube on the dynamic response of oil tube and packer are investigated. On this basis, a basic principle of the combination design of shock absorber and oil tube is proposed to improve the mechanical state of downhole tools. The study results can provide theoretical support for the design of downhole perforation-test joint operation.

Effect of scandia doping method on the emission uniformity of scandate cathode with Sc2O3–W matrix

International Nuclear Information System (INIS)

Wang, Jinshu; Lai, Chen; Liu, Wei; Yang, Fan; Zhang, Xizhu; Cui, Yuntao; Zhou, Meiling

2013-01-01

Graphical abstract: Emission uniformity of the cathodes prepared by mechanical mixing (a) and spray drying method (b). - Highlights: • The emission uniformity of scandate cathodes has been quantitively obtained. • The nanoparticles on the cathode surface lead to the electric field enhancement. • The cathode prepared by spray drying method exhibits good emission uniformity. - Abstract: Scandia doped tungsten matrix dispenser cathodes were manufactured using scandia doped tungsten powder prepared by mechanical mixing, liquid–solid doping and a spray drying method. It is found the macrostructure of the cathode depended on the powder preparation method. The cathode prepared using the powder prepared by spray drying method had a homogenous and porous matrix characterized with grains with a diameter of less than 1 μm and with many nanoparticles distributing uniformly around these grains. The cathode with submicron structure and uniform distribution of scandia exhibited good emission uniformity. The emission uniformity ΔJ/J of the cathode prepared by spray drying method was 0.17, about 6 times lower than that of the cathode prepared by mechanical mixing method. The calculation results showed that the nanoparticles led to electric field enhancement. A Ba–Sc–O multilayer on the cathode surface and nanoparticles distributing mainly on W grains contributed to the emission property of the cathode

Monitoring local redox processes in LiNi0.5Mn1.5O4 battery cathode material by in operando EPR spectroscopy

Science.gov (United States)

Niemöller, Arvid; Jakes, Peter; Eurich, Svitlana; Paulus, Anja; Kungl, Hans; Eichel, Rüdiger-A.; Granwehr, Josef

2018-01-01

Despite the multitude of analytical methods available to characterize battery cathode materials, identifying the factors responsible for material aging is still challenging. We present the first investigation of transient redox processes in a spinel cathode during electrochemical cycling of a lithium ion battery by in operando electron paramagnetic resonance (EPR). The battery contains a LiNi0.5Mn1.5O4 (LNMO) spinel cathode, which is a material whose magnetic interactions are well understood. The evolution of the EPR signal in combination with electrochemical measurements shows the impact of Mn3+ on the Li+ motion inside the spinel. Moreover, state of charge dependent linewidth variations confirm the formation of a solid solution for slow cycling, which is taken over by mixed models of solid solution and two-phase formation for fast cycling due to kinetic restrictions and overpotentials. Long-term measurements for 480 h showed the stability of the investigated LNMO, but also small amounts of cathode degradation products became visible. The results point out how local, exchange mediated magnetic interactions in cathode materials are linked with battery performance and can be used for material characterization.

In Situ Foaming of Porous (La _0.6 Sr _0.4 ) _0.98 (Co _0.2 Fe _0.8 ) O _3-δ (LSCF) Cathodes for Solid Oxide Fuel Cell Applications

Energy Technology Data Exchange (ETDEWEB)

Gandavarapu, Sodith [US DOE-National Energy Technology Laboratory, 3610 Collins Ferry Road P.O.Box.880 Morgantown West Virginia 26507; Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown West Virginia 26506; Sabolsky, Edward [US DOE-National Energy Technology Laboratory, 3610 Collins Ferry Road P.O.Box.880 Morgantown West Virginia 26507; Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown West Virginia 26506; Sabolsky, Katarzyna [Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown West Virginia 26506; Gerdes, Kirk [US DOE-National Energy Technology Laboratory, 3610 Collins Ferry Road P.O.Box.880 Morgantown West Virginia 26507

2013-07-18

A binder system containing polyurethane precursors was used to in situ foam (direct foam) a (La{sub 0.6}Sr{sub 0.4}){sub 0.98} (Co{sub 0.2} Fe{sub 0.8}) O{sub 3-{ delta}} (LSCF) composition for solid oxide fuel cell (SOFC) cathode applications. The relation between in situ foaming parameters on the final microstructure and electrochemical properties was characterized by microscopy and electrochemical impedance spectroscopy (EIS), respectively. The optimal porous cathode architecture was formed with a 70 vol% solids loading within a polymer precursor composition with a volume ratio of 8:4:1 (isocyanate: PEG: surfactant) in a terpineol-based ink vehicle. The resultant microstructure displayed a broad pore size distribution with highly elongated pore structure.

Clinical Factors of Delayed Perforation after Endoscopic Submucosal Dissection for Gastric Neoplasms

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Yoshinobu Yamamoto

2017-01-01

Full Text Available Background. Delayed perforation is a rare but severe complication of endoscopic submucosal dissection (ESD for early gastric neoplasm (EGN. The aim of this study was to clarify clinical factors related to delayed perforation after ESD. Methods. A total of 1158 consecutive patients with 1199 EGNs underwent ESD at our hospital between January 2000 and December 2015. Univariate analysis was used to identify clinicopathological factors related to delayed perforation. Moreover, duration of cautery needed for hemostasis was measured by comparison between perforated and nonperforated points in patients with delayed perforation. Results. Delayed perforation occurred in 5 of 1158 consecutive patients with 1199 EGNs who underwent ESD (0.42%. All cases were diagnosed within 24 h after ESD and recovered with conservative management. On univariate analysis, location in the upper stomach was the factor most significantly associated with delayed perforation (P<0.01. Duration of cautery needed for hemostasis was significantly longer at perforated points (9 s than at nonperforated points (3.5 s in five patients. Conclusions. Location in the upper stomach was the risk factor most prominently associated with delayed perforation after ESD for EGNs. In addition, delayed perforation appears associated with excessive electrocautery for hemostasis.

Clinicopathological Analysis of Factors Related to Colorectal Tumor Perforation

OpenAIRE

Medina-Arana, Vicente; Martínez-Riera, Antonio; Delgado-Plasencia, Luciano; Rodríguez-González, Diana; Bravo-Gutiérrez, Alberto; Álvarez-Argüelles, Hugo; Alarcó-Hernández, Antonio; Salido-Ruiz, Eduardo; Fernández-Peralta, Antonia M.; González-Aguilera, Juan J.

2015-01-01

Abstract Colorectal tumor perforation is a life-threatening complication of this disease. However, little is known about the anatomopathological factors or pathophysiologic mechanisms involved. Pathological and immunohistochemical analysis of factors related with tumoral neo-angiogenesis, which could influence tumor perforation are assessed in this study. A retrospective study of patients with perforated colon tumors (Group P) and T4a nonperforated (controls) was conducted between 2001 and 20...

Predictors of appendiceal perforation in an equal access system.

Science.gov (United States)

Walker, Avery; Hatch, Quinton; Drake, Thurston; Nelson, Daniel W; Fitzpatrick, Emilie; Bingham, Jason; Black, George; Maykel, Justin A; Steele, Scott R

2014-07-01

Discrepancies in socioeconomic factors have been associated with higher rates of perforated appendicitis. As an equal-access health care system theoretically removes these barriers, we aimed to determine if remaining differences in demographics, education, and pay result in disparate outcomes in the rate of perforated appendicitis. All patients undergoing appendectomy for acute appendicitis (November 2004-October 2009) at a tertiary care equal access institution were categorized by demographics and perioperative data. Rank of the sponsor was used as a surrogate for economic status. A multivariate logistic regression model was performed to determine patient and clinical characteristics associated with perforated appendicitis. A total of 680 patients (mean age 30±16 y; 37% female) were included. The majority were Caucasian (56.4% [n=384]; African Americans 5.6% [n=38]; Asians 1.9% [n=13]; and other 48.9% [n=245]) and enlisted (87.2%). Overall, 6.4% presented with perforation, with rates of 6.6%, 5.8%, and 6.7% (P=0.96) for officers, enlisted soldiers, and contractors, respectively. There was no difference in perforation when stratified by junior or senior status for either officers or enlisted (9.3% junior versus 4.40% senior officers, P=0.273; 6.60% junior versus 5.50% senior enlisted, P=0.369). On multivariate analysis, parameters such as leukocytosis and temperature, as well as race and rank were not associated with perforation (P=0.7). Only age had a correlation, with individuals aged 66-75 y having higher perforation rates (odds ratio, 1.04; 95% confidence interval, 1.02-1.05; P<0.001). In an equal-access health care system, older age, not socioeconomic factors, correlated with increased appendiceal perforation rates. Published by Elsevier Inc.

Influence of operating microscope in the sealing of cervical perforations.

Science.gov (United States)

Schmidt, Bruna Schwingel; Zaccara, Ivana Maria; Reis Só, Marcus Vinícius; Kuga, Milton Carlos; Palma-Dibb, Regina Guenka; Kopper, Patrícia Maria Poli

2016-01-01

Accidental root canal perforations are among the main complications of endodontic treatment. This study evaluated the influence of operating microscope (OM) in the marginal adaptation of mineral trioxide aggregate (MTA) (Angelus(®)) and glass ionomer (Vitremer) inserted into cervical perforations. Perforations were made in the cervical third of the buccal wall of the root canal in mandibular incisors. Next, the teeth were divided into four groups (N = 10): MG - MTA without OM; VG - Vitremer without OM; MOMG - MTA with OM; VOMG - Vitremer with OM. The perforations were sealed according to the group and the teeth were prepared for analysis by confocal laser scanning microscope. Images of perforation region (1,024×) were made and the gap presented by the materials was measured using the Image J program. LEXT OLS4100 three dimensional (3D) measuring laser microscope measured the volumetric misfit. Data of gap were analyzed by Kruskal-Wallis and Dunn's tests. Analysis of variance (ANOVA) and Tukey's tests compared the volumetric misfits. The results showed lower volume and gap in the interface dentin/material in VOMG compared to the other groups (P < 0.05). The use of OM improved the quality of cervical perforations sealed with Vitremer, being indicated in clinical situations of iatrogenic cervical perforations.

Laparoscopic Primary Colorrhaphy for Acute Iatrogenic Perforations during Colonoscopy

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Eric M. Haas

2013-01-01

Full Text Available Purpose. We present our experience with laparoscopic colorrhaphy as definitive surgical modality for the management of colonoscopic perforations. Methods. Over a 17-month period, we assessed the outcomes of consecutive patients presenting with acute colonoscopic perforations. Patient characteristics and perioperative parameters were tabulated. Postoperative outcomes were evaluated within 30 days following discharge. Results. Five female patients with a mean age of 71.4 ± 9.7 years (range: 58–83, mean BMI of 26.4 ± 3.4 kg/m2 (range: 21.3–30.9, and median ASA score of 2 (range: 2-3 presented with acute colonoscopic perforations. All perforations were successfully managed through laparoscopic colorrhaphy within 24 hours of development. The perforations were secondary to direct trauma (n=3 or thermal injury (n=2 and were localized to the sigmoid (n=4 or cecum (n=1. None of the patients required surgical resection, diversion, or conversion to an open procedure. No intra- or postoperative complications were encountered. The mean length of hospital stay was 3.8 ± 0.8 days (range: 3–5. There were no readmissions or reoperations. Conclusion. Acute colonoscopic perforations can be safely managed via laparoscopic primary repair without requiring resection or diversion. Early recognition and intervention are essential for successful outcomes.

Characteristics of rapid-thermal-annealed LiCoO2 cathode film for an all-solid-state thin film microbattery

International Nuclear Information System (INIS)

Kim, Han-Ki; Yoon, Young Soo

2004-01-01

We report on the fabrication of a LiCoO 2 film for an all-solid-state thin film microbattery by using a rapid-thermal-annealing (RTA) process. The LiCoO 2 films were grown by rf magnetron sputtering using a synthesized LiCoO 2 target in a [O 2 /(Ar+O 2 )] ratio of 10%. Scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES) analysis results showed that the surface layer on the as-deposited LiCoO 2 film was completely removed by rapid thermal annealing process in oxygen ambient for 20 min. In addition, the thin film microbattery fabricated with the annealed LiCoO 2 film shows fairly stable cyclability with a specific discharge capacity of 56.49 μAh/cm2 μm. These results show the possibility of the RTA LiCoO 2 film and rapid thermal annealing process being a promising cathode material and annealing process for thin film microbatteries, respectively

Esophageal Perforation due to Transesophageal Echocardiogram: New Endoscopic Clip Treatment

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John Robotis

2014-07-01

Full Text Available Esophageal perforation due to transesophageal echocardiogram (TEE during cardiac surgery is rare. A 72-year-old female underwent TEE during an operation for aortic valve replacement. Further, the patient presented hematemesis. Gastroscopy revealed an esophageal bleeding ulcer. Endoscopic therapy was successful. Although a CT scan excluded perforation, the patient became febrile, and a second gastroscopy revealed a big perforation at the site of ulcer. The patient's clinical condition required endoscopic intervention with a new OTSC® clip (Ovesco Endoscopy, Tübingen, Germany. The perforation was successfully sealed. The patient remained on intravenous antibiotics, proton pump inhibitors and parenteral nutrition for few days, followed by enteral feeding. She was discharged fully recovered 3 months later. We clearly demonstrate an effective, less invasive treatment of an esophageal perforation with a new endoscopic clip.

Evaluation of Ca3(Co,M2O6 (M=Co, Fe, Mn, Ni as new cathode materials for solid-oxide fuel cells

Directory of Open Access Journals (Sweden)

Fushao Li

2015-10-01

Full Text Available Series compounds Ca3(Co0.9M0.12O6 (M=Co, Fe, Mn, Ni with hexagonal crystal structure were prepared by sol–gel route as the cathode materials for solid oxide fuel cells (SOFCs. Effects of the varied atomic compositions on the structure, electrical conductivity, thermal expansion and electrochemical performance were systematically evaluated. Experimental results showed that the lattice parameters of Ca3(Co0.9Fe0.12O6 and Ca3(Co0.9Mn0.12O6 were both expanded to certain degree. Electron-doping and hole-doping effects were expected in Ca3(Co0.9Mn0.12O6 and Ca3(Co0.9Ni0.12O6 respectively according to the chemical states of constituent elements and thermal-activated behavior of electrical conductivity. Thermal expansion coefficients (TEC of Ca3(Co0.9M0.12O6 were measured to be distributed around 16×10−6 K−1, and compositional elements of Fe, Mn, and Ni were especially beneficial for alleviation of the thermal expansion problem of cathode materials. By using Ca3(Co0.9M0.12O6 as the cathodes operated at 800 °C, the interfacial area-specific resistance varied in the order of M=Cocathode materials for SOFCs.

Perforated duodenal diverticulum caused by Bezoar: A case report

Energy Technology Data Exchange (ETDEWEB)

Lee, Eun Jung; Moon, Sung Kyoung; Park, Seong Jin; Lim, Joo Won; Lee, Dong Ho; Ko, Young Tae [Dept. of Radiology, College of Medicine, Kyung Hee University, Seoul (Korea, Republic of)

2013-11-15

Duodenal diverticulum is common, but its perforation is a rare complication. Duodenal diverticulum perforation requires prompt treatments because of its high mortality rate. However, an accurate diagnosis is difficult to make due to nonspecific symptoms and signs. It can be misdiagnosed as pancreatitis, cholecystitis, or peptic ulcer. Herein, we report a case of perforated duodenal diverticulum caused by bezoar in a 33-year-old woman whom was diagnosed by abdomen computed tomography and ultrasonography.

Duodenal perforation: an unusual complication of sickle cell anemia

OpenAIRE

Acıpayam, Can; Aldıç, Güliz; Akçora, Bülent; Çelikkaya, Mehmet Emin; Aşkar, Hasan; Dorum, Bayram Ali

2014-01-01

Duodenal perforation in childhood is a rare condition with a high mortality rate if not treated surgically. Primary gastroduodenal perforation is frequently associated with peptic ulcer and exhibits a positive family history. Helicobacter pylorus is the most significant agent. Secondary gastroduodenal perforation may be a finding of specific diseases, such as Crohn disease, or more rarely may be associated with diseases such as cystic fibrosis or sickle cell anemia. A 14-year-old boy presente...

Spectrum of Perforation Peritonitis in Delhi: 77 Cases Experience

OpenAIRE

Yadav, Dinesh; Garg, Puneet K.

2012-01-01

Perforation peritonitis is the most common surgical emergency encountered by surgeons all over the world as well in India. The spectrum of etiology of perforation peritonitis in tropical countries continues to differ from its western counterpart. This study was conducted at Hindu Rao Hospital, Municipal Corporation of Delhi, New Delhi, India, designed to highlight the spectrum of perforation peritonitis in the eastern countries and to improve its outcome. This prospective study included 77 co...

Perforated duodenal diverticulum caused by Bezoar: A case report

International Nuclear Information System (INIS)

Lee, Eun Jung; Moon, Sung Kyoung; Park, Seong Jin; Lim, Joo Won; Lee, Dong Ho; Ko, Young Tae

2013-01-01

Duodenal diverticulum is common, but its perforation is a rare complication. Duodenal diverticulum perforation requires prompt treatments because of its high mortality rate. However, an accurate diagnosis is difficult to make due to nonspecific symptoms and signs. It can be misdiagnosed as pancreatitis, cholecystitis, or peptic ulcer. Herein, we report a case of perforated duodenal diverticulum caused by bezoar in a 33-year-old woman whom was diagnosed by abdomen computed tomography and ultrasonography.

Perforated peptic ulcer

Science.gov (United States)

Søreide, Kjetil; Thorsen, Kenneth; Harrison, Ewen M.; Bingener, Juliane; Møller, Morten H.; Ohene-Yeboah, Michael; Søreide, Jon Arne

2015-01-01

Summary Perforated peptic ulcer (PPU) is a frequent emergency condition worldwide with associated mortality up to 30%. A paucity of studies on PPU limits the knowledge base for clinical decision-making, but a few randomised trials are available. While Helicobacter pylori and use of non-steroidal anti-inflammatory drugs are frequent causes of PPU, demographic differences in age, gender, perforation location and aetiology exist between countries, as do mortality rates. Clinical prediction rules are used, but accuracy varies with study population. Early surgery, either by laparoscopic or open repair, and proper sepsis management are essential for good outcome. Selected patients can perhaps be managed non-operatively or with novel endoscopic approaches, but validation in trials is needed. Quality of care, sepsis care-bundles and postoperative monitoring need further evaluation. Adequate trials with low risk of bias are urgently needed for better evidence. Here we summarize the evidence for PPU management and identify directions for future clinical research. PMID:26460663

Surgical management of perforated duodenal ulcer: the changing scene.

Science.gov (United States)

Plummer, J M; McFarlane, M E C; Newnham

2004-12-01

To determine the management of perforated duodenal ulcer at the University Hospital of the West Indies (UHWI) in this era of Helicobacter pylori, the medical records of all patients seen at the UHWI during the period July 1997 to June 2002 with an intra-operative diagnosis of perforated peptic ulcer were reviewed The records were analyzed for the following: age, gender, duration of symptoms, non-steroidal anti-inflammatory drug (NSAID) use, smoking status, operative repair duration of hospitalization, Helicobacter pylori status and medical therapy, peri-operative complications, mortality and recurrence. Ninety per cent of the cases were males. All females in whom perforation occurred were age 50 years and older compared to males where 58% of cases presented before age 50 years. Perforations in acute ulcers occurred in 80% of cases. The majority of patients were male smokers. Non-steroidal anti-inflammatory drug use was also an important risk factor in elderly females. Simple surgical closure and standard triple therapy antibiotics to eradicate Helicobacter pylori was the most common treatment offered. Mortality was one per cent and follow-up poor but 11% of patients had documented recurrent peptic ulceration. In this study population, perforated duodenal ulcer occured overwhelmingly in males less than 50 years of age. There is a trend towards exclusive simple surgical closure and H pylori eradication at the UHWI for patients with perforated duodenal ulcer but this needs to be supported by documentation of H pylori prevalence in the population of patients presenting with perforated peptic ulcers.

Factors related to persisting perforations after ventilation tube insertion.

Science.gov (United States)

O'Connell Ferster, Ashley P; Tanner, April Michelle; Karikari, Kodjo; Roberts, Christopher; Wiltz, Derek; Carr, Michele M

2016-02-01

Over a million ventilation tubes are placed annually in the United States, making this one of the most commonly performed procedures in the field of medicine. Certain factors increase the risk of persistent tympanic membrane perforation following the extrusion of short term ventilation tubes. Persistent perforations may fail to heal on their own, necessitating surgical closure to avoid conductive hearing loss. It is important to detect factors that may predict children who are at increased risk for persistent perforations. This study was a retrospective chart review that involved 757 patients between 2003 and 2008. The patients studied were within the age of 2 months-17 years, and all had short term tubes placed. The chart data also included demographic information, comorbidities, and information related to tube insertion and follow-up care. Chi-square, t-test, and multivariate logistic regression were conducted to compare variables between patients with perforations and those without. Data from 757 patients was analyzed, showing that perforation rate is associated with rhinorrhea, operative tube removal, aural polyps, and otorrhea (OR 1.72, 8.16, 4.69, and 1.72 respectively). The absence of otorrhea decreased the likelihood of TM perforations and no significant differences were found in gender, total number of sets of tubes, type of tube, use of nasal steroids, adenoidectomy, or nasal congestion. Our findings suggest that children with rhinorrhea, otorrhea, aural polyps, or prolonged intubation requiring operative tube removal should be identified clinically as children at risk of persisting perforation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Common Bile Duct Perforation Due to Tuberculosis: A Case Report

OpenAIRE

Razman Jarmin; Shaharin Shaharuddin

2004-01-01

A young man with HIV presented with biliary peritonitis secondary to spontaneous common bile duct perforation. Investigation revealed that the perforation was due to Mycobacterium tuberculosis. Tuberculosis of the bile duct is uncommon and usually presents with obstructive jaundice due to stricture. Bile duct perforation due to tuberculosis is extremely rare. Its management is discussed.

Thin metal organic frameworks coatings by cathodic electrodeposition for solid-phase microextraction and analysis of trace exogenous estrogens in milk.

Science.gov (United States)

Lan, Hangzhen; Pan, Daodong; Sun, Yangying; Guo, Yuxing; Wu, Zhen

2016-09-21

Cathodic electrodeposition (CED) has received great attention in metal-organic frameworks (MOFs) synthesis due to its distinguished properties including simplicity, controllability, mild synthesis conditions, and product continuously. Here, we report the fabrication of thin (Et3NH)2Zn3(BDC)4 (E-MOF-5) film coated solid phase microextraction (SPME) fiber by a one-step in situ cathodic electrodeposition strategy. Several etched stainless steel fibers were placed in parallel in order to achieve simultaneously electrochemical polymerization. The influence of different polymerization parameters Et3NHCl concentration and polymerization time were evaluated. The proposed method requires only 20 min for the preparation of E-MOF-5 coating. The optimum coating showed excellent thermal stability and mechanical durability with a long lifetime of more than 120 repetitions SPME operations, and also exhibited higher extraction selectivity and capacity to four estrogens than commonly-used commercial PDMS coating. The limits of detection for the estrogens were 0.17-0.56 ng mL(-1). Fiber-to-fiber reproducibility (n = 8) was in the respective ranges of 3.5%-6.1% relative standard deviation (RSD) for four estrogens for triplicate measurements at 200 ng mL(-1). Finally, the (E-MOF-5) coated fiber was evaluated for ethinylestradiol (EE2), bisphenol A (BPA), diethylstilbestrol (DES), and hexestrol (HEX) extraction in the spiked milk samples. The extraction performance of this new coating was satisfied enough for repeatable use without obvious decline. Copyright © 2016 Elsevier B.V. All rights reserved.

A development of solid oxide fuel cell technology

Energy Technology Data Exchange (ETDEWEB)

Lim, Hee Chun; Lee, Chang Woo [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center; Kim, Kwy Youl; Yoon, Moon Soo; Kim, Ho Ki; Kim, Young Sik; Mun, Sung In; Eom, Sung Wuk [Korea Electrotechnology Research Inst., Changwon (Korea, Republic of)

1996-12-31

Solid oxide fuel cell which was consisted of ceramics has high power density and is very simple in shape. The project named A development of SOFC(Solid Oxide Fuel Cell) technology is to develop the unit cell fabrication processing and to evaluate the unit cell of solid oxide full cell. In this project, a manufacturing process of cathode by citrate method and polymeric precursor methods were established. By using tape casting method, high density thin electrolyte was manufactured and has high performance. Unit cell composed with La{sub 17}Sr{sub 13}Mn{sub 3} as cathode, 8YSZ electrolyte and 50% NiYSZ anode had a performance of O.85 W/cm{sup 2} and recorded 510 hours operation time. On the basis of these results. 100 cm{sup 2} class unit cell will be fabricated and tests in next program (author). 59 refs., 120 figs.

A development of solid oxide fuel cell technology

Energy Technology Data Exchange (ETDEWEB)

Lim, Hee Chun; Lee, Chang Woo [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center; Kim, Kwy Youl; Yoon, Moon Soo; Kim, Ho Ki; Kim, Young Sik; Mun, Sung In; Eom, Sung Wuk [Korea Electrotechnology Research Inst., Changwon (Korea, Republic of)

1995-12-31

Solid oxide fuel cell which was consisted of ceramics has high power density and is very simple in shape. The project named A development of SOFC(Solid Oxide Fuel Cell) technology is to develop the unit cell fabrication processing and to evaluate the unit cell of solid oxide full cell. In this project, a manufacturing process of cathode by citrate method and polymeric precursor methods were established. By using tape casting method, high density thin electrolyte was manufactured and has high performance. Unit cell composed with La{sub 17}Sr{sub 13}Mn{sub 3} as cathode, 8YSZ electrolyte and 50% NiYSZ anode had a performance of O.85 W/cm{sup 2} and recorded 510 hours operation time. On the basis of these results. 100 cm{sup 2} class unit cell will be fabricated and tests in next program (author). 59 refs., 120 figs.

Spectrum of perforation peritonitis in India-review of 504 consecutive cases

OpenAIRE

Jhobta, Rajender Singh; Attri, Ashok Kumar; Kaushik, Robin; Sharma, Rajeev; Jhobta, Anupam

2006-01-01

Abstract Background/objective Perforation peritonitis is the most common surgical emergency in India. The spectrum of etiology of perforation in Tropical countries continues to be different from its Western counterpart. The objective of the study was to highlight the spectrum of perforation peritonitis as encountered by us at Government Medical College and Hospital (GMCH), Chandigarh. Methods Five hundred and four consecutive cases of perforation peritonitis over a period of five years were r...

Diaphragmatic eventration complicated by gastric volvulus with perforation

OpenAIRE

Gupta, V; Chandra, A; Gupta, P

2012-01-01

Eventration of the diaphragm with gastric volvulus is uncommon. Gastric perforation in these cases is rare and usually associated with acute gastric volvulus with strangulation. We describe a case of diaphragmatic eventration with chronic gastric volvulus with gastric perforation without strangulation in an elderly man.

Common Bile Duct Perforation Due to Tuberculosis: A Case Report

Directory of Open Access Journals (Sweden)

Razman Jarmin

2004-10-01

Full Text Available A young man with HIV presented with biliary peritonitis secondary to spontaneous common bile duct perforation. Investigation revealed that the perforation was due to Mycobacterium tuberculosis. Tuberculosis of the bile duct is uncommon and usually presents with obstructive jaundice due to stricture. Bile duct perforation due to tuberculosis is extremely rare. Its management is discussed.

Preoperative factors influencing mortality and morbidity in peptic ulcer perforation.

Science.gov (United States)

Sivaram, P; Sreekumar, A

2018-04-01

Perforated peptic ulcer is one of the most common surgical emergencies worldwide. With the improvement in medical therapy for peptic ulcers, the number of elective surgical procedures has come down. However, the incidence of perforated peptic ulcer is still increasing and remains as a substantial health problem with significant postoperative morbidity and mortality. This study aimed to find out the association between various preoperative and intraoperative factors with the postoperative mortality and morbidity in patients operated for peptic ulcer perforation. This prospective observational study had a time based sample of 101 perforation peritonitis cases admitted to the surgical wards of a tertiary care center from February 2015 to January 2016 who underwent laparotomy, diagnosed to have peptic ulcer perforation and underwent simple closure with an omental patch. Data regarding age, gender, presenting complaints, time elapsed from the onset of symptoms to surgery, physical examination findings, comorbid diseases, laboratory and imaging findings, intraoperative findings, length of hospital stay, postoperative morbidity, and mortality were recorded and analyzed. Female gender, older age group, perforation surgery interval more than 36 h, and size of perforation more than 1 cm 2 were found to be significant factors influencing postoperative mortality and morbidity. Postoperative morbidity was also associated with comorbid diseases. Abnormal renal function on presentation was identified as an additional risk factor for postoperative morbidity and longer hospital stay. An understanding of these factors, identification of patients at risk and early intervention can help in reducing the postoperative morbidity and mortality in peptic ulcer perforation.

Jejunal Diverticular Perforation due to Enterolith

Directory of Open Access Journals (Sweden)

Ronaldo Nonose

2011-08-01

Full Text Available Jejunal diverticulosis is a rare entity with variable clinical and anatomical presentations. Although there is no consensus on the management of asymptomatic jejunal diverticular disease, some complications are potentially life-threatening and require early surgical treatment. Small bowel perforation secondary to jejunal diverticulitis by enteroliths is rare. The aim of this study was to report a case of small intestinal perforation caused by a large jejunal enterolith. An 86-year-old woman was admitted with signs of diffuse peritonitis. After initial fluid recovery the patient underwent emergency laparotomy. The surgery showed that she had small bowel diverticular disease, mainly localized in the proximal jejunum. The peritonitis was due to intestinal perforation caused by an enterolith 12 cm in length, localized inside one of these diverticula. The intestinal segment containing the perforated diverticulum with the enterolith was removed and an end-to-end anastomosis was done to reconstruct the intestinal transit. The patient recovered well and was discharged from hospital on the 5th postoperative day. There were no signs of abdominal pain 1 year after the surgical procedure. Although jejunal diverticular disease with its complications, such as formation of enteroliths, is difficult to suspect in patients with peritonitis, it should be considered as a possible source of abdominal infection in the elderly patient when more common diagnoses have been excluded.

Sonographic templates of newborn perforator stroke.

Science.gov (United States)

Abels, Lyanne; Lequin, Maarten; Govaert, Paul

2006-07-01

Many paediatric strokes occur in the perinatal period. Improvement in neuroimaging has increased detection in newborns with neurological symptoms. To define sonographic templates of neonatal stroke in the territory of perforators of the anterior choroidal artery (AChA) and the anterior (ACA), middle (MCA) and posterior (PCA) cerebral arteries. In 24 neonates with perforator stroke, we retrospectively studied antenatal and perinatal events. Brain sonography was performed with an 8.5-MHz probe. Only hyperechoic lesions in the thalamus and/or striatum and/or centrum semiovale were included. MRI was obtained using a 1.5-T machine. We detected 28 perforator strokes in 24 infants (6 preterm): 5 MCA medial striate, 8 MCA lateral striate, 3 MCA centrum semiovale, 4 ACA Heubner's, 5 PCA thalamic arteries, 1 AChA, and 2 hypothalamic perforators. We attributed clinical seizures to stroke in two infants only. Catheter-related embolism (certain in three, possible in six others) and birth trauma (two) were probable causes. Specific conditions were found in six others. Only one infant (in nine evaluated) had an increased prothrombotic risk (fII mutation). In describing the lesions, we focused on the templates of infarction as seen in a parasagittal US sweep. Infarcts were confirmed by MRI in 21 patients. Our study showed that infarct topography can be evaluated reliably with brain sonography. This is important given the asymptomatic character of most lesions.

Sen perforation af tyndtarm efter laparoskopisk gastrisk bypass

DEFF Research Database (Denmark)

Spanager, Lene; Sigild, Ulf Henrik; Neuenschwander, Anders Ulrich

2010-01-01

We present two cases in which the patients were admitted to a local hospital with acute abdominal pain four or five months after having undergone laparoscopic gastric bypass. In both cases, operation revealed a perforation of the small bowel close to the distal anastomosis. In the first case......, a massive constipation of the small bowel was most likely a contributing factor. In the second case, the cause was a kink of the entero-entero anastomosis leading to obstruction and finally perforation of the biliary limp. Late perforations are among the rarely reported complications associated with gastric...

Phase transition of a cobalt-free perovskite as a high-performance cathode for intermediate-temperature solid oxide fuel cells.

Science.gov (United States)

Jiang, Shanshan; Zhou, Wei; Niu, Yingjie; Zhu, Zhonghua; Shao, Zongping

2012-10-01

It is generally recognized that the phase transition of a perovskite may be detrimental to the connection between cathode and electrolyte. Moreover, certain phase transitions may induce the formation of poor electronic and ionic conducting phase(s), thereby lowering the electrochemical performance of the cathode. Here, we present a study on the phase transition of a cobalt-free perovskite (SrNb(0.1)Fe(0.9)O(3-δ), SNF) and evaluate its effect on the electrochemical performance of the fuel cell. SNF exists as a primitive perovskite structure with space group P4mm (99) at room temperature. As evidenced by in situ high-temperature X-ray diffraction measurements over the temperature range of 600 to 1000 °C, SNF undergoes a transformation to a tetragonal structure with a space group I4/m (87). This phase transition is accompanied by a moderate change in the volume, allowing a good cathode/electrolyte interface on thermal cycling. According to the electrochemical impedance spectroscopy evaluation, the I4/m phase exhibits positive effects on the cathode's performance, showing the highest oxygen reduction reaction activity of cobalt-free cathodes reported so far. This activity improvement is attributed to enhanced oxygen surface processes. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Perforated pyloroduodenal peptic ulcer and sonography.

Science.gov (United States)

Kuzmich, Siarhei; Harvey, Chris J; Fascia, Daniel T M; Kuzmich, Tatsiana; Neriman, Deena; Basit, Rizwan; Tan, Kai Lee

2012-11-01

The purpose of this article is to illustrate the spectrum of sonographic findings in perforated pyloroduodenal peptic ulcer and discuss the potential role of sonography in the diagnosis. Although sonography is not the first-line investigation of choice in suspected perforated peptic ulcer, understanding of the characteristic appearances seen during general abdominal sonography may aid the reader in the diagnosis of this important and sometimes overlooked cause of nonspecific abdominal pain. This may shorten time to the diagnosis and ultimate surgical management.

Spontaneous Uterine Perforation due to Pyometra Presenting as Acute Abdomen

Directory of Open Access Journals (Sweden)

Loabat Geranpayeh

2006-01-01

Full Text Available Spontaneous perforation of the uterus is rare, its incidence being about 0.01%–0.05%. We report a rare case of diffuse peritonitis caused by spontaneously perforated pyometra. A 63-year-old woman with severe abdominal pain was admitted to our hospital. Laparotomy was performed because of the suspicion of gastrointestinal perforation with generalized peritonitis. At laparotomy, about 900 mL of pus was found in the peritoneal cavity. There were no abnormal findings in the alimentary tract, liver, or gallbladder. A total abdominal hysterectomy with bilateral salpingo-oophorectomy was performed. Pathological investigation of the surgical specimen revealed endometritis and myometritis of the uterus; but there was no evidence of malignancy, and the cervical canal was patent. Although spontaneously perforated pyometra is rare, a perforated pyometra should therefore also be considered when elderly women present with acute abdominal pain.

Break‐down of Losses in High Performing Metal‐Supported Solid Oxide Fuel Cells

DEFF Research Database (Denmark)

Kromp, A.; Nielsen, Jimmi; Blennow Tullmar, Peter

2013-01-01

in the metal support, the electrochemical fuel oxidation at the anode and the oxygen reduction in the mixed ionic electronic conducting cathode. An additional process with a rather high relaxation frequency was attributed to the formation of insulating interlayers at the cathode/electrolyte‐interface. Based...... on these results, selective measures to improve performance and stability, such as (i) PVD‐deposited CGO buffer layer preventing solid state reaction between cathode and the zirconia‐based electrolyte, (ii) LSC‐CGO based in‐situ sintered cathodes and (iii) reduced corrosion of the metal support, were adopted...

Risk of surgical glove perforation in oral and maxillofacial surgery.

Science.gov (United States)

Kuroyanagi, N; Nagao, T; Sakuma, H; Miyachi, H; Ochiai, S; Kimura, Y; Fukano, H; Shimozato, K

2012-08-01

Oral and maxillofacial surgery, which involves several sharp instruments and fixation materials, is consistently at a high risk for cross-contamination due to perforated gloves, but it is unclear how often such perforations occur. This study aimed to address this issue. The frequency of the perforation of surgical gloves (n=1436) in 150 oral and maxillofacial surgeries including orthognathic surgery (n=45) was assessed by the hydroinsufflation technique. Orthognathic surgery had the highest perforation rate in at least 1 glove in 1 operation (91.1%), followed by cleft lip and palate surgery (55.0%), excision of oral soft tumour (54.5%) and dental implantation (50.0%). The perforation rate in scrub nurses was 63.4%, followed by 44.4% in surgeons and first assistants, and 16.3% in second assistants. The odds ratio for the perforation rate in orthognathic surgery versus other surgeries was 16.0 (95% confidence interval: 5.3-48.0). The protection rate offered by double gloving in orthognathic surgery was 95.2%. These results suggest that, regardless of the surgical duration and blood loss in all fields of surgery, orthognathic surgery must be categorized in the highest risk group for glove perforation, following gynaecological and open lung surgery, due to the involvement of sharp objects. Copyright © 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Perforated peptic ulcer associated with abdominal compartment syndrome.

Science.gov (United States)

Lynn, Jiun-Jen; Weng, Yi-Ming; Weng, Chia-Sui

2008-11-01

Abdominal compartment syndrome (ACS) is defined as an increased intra-abdominal pressure with adverse physiologic consequences. Abdominal compartment syndrome caused by perforated peptic ulcer is rare owing to early diagnosis and management. Delayed recognition of perforated peptic ulcer with pneumoperitoneum, bowel distension, and decreased abdominal wall compliance can make up a vicious circle and lead to ACS. We report a case of perforated peptic ulcer associated with ACS. A 74-year-old man with old stroke and dementia history was found to have distended abdomen, edema of bilateral legs, and cyanosis. Laboratory tests revealed deterioration of liver and kidney function. Abdominal compartment syndrome was suspected, and image study was arranged to find the cause. The study showed pneumoperitoneum, contrast stasis in heart with decreased caliber of vessels below the abdominal aortic level, and diffuse lymphedema at the abdominal walls. Emergent laparotomy was performed. Perforated peptic ulcer was noted and the gastrorrhaphy was done. The symptoms, and liver and kidney function improved right after emergent operation.

Ab initio study of vacancy formation in cubic LaMnO{sub 3} and SmCoO{sub 3} as cathode materials in solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Olsson, Emilia; Aparicio-Anglès, Xavier [Department of Chemistry, University College London, London WC1H 0AJ (United Kingdom); Leeuw, Nora H. de, E-mail: deleeuwn@cardiff.ac.uk [Department of Chemistry, University College London, London WC1H 0AJ (United Kingdom); School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT (United Kingdom)

2016-07-07

Doped LaMnO{sub 3} and SmCoO{sub 3} are important solid oxide fuel cell cathode materials. The main difference between these two perovskites is that SmCoO{sub 3} has proven to be a more efficient cathode material than LaMnO{sub 3} at lower temperatures. In order to explain the difference in efficiency, we need to gain insight into the materials’ properties at the atomic level. However, while LaMnO{sub 3} has been widely studied, ab initio studies on SmCoO{sub 3} are rare. Hence, in this paper, we perform a comparative DFT + U study of the structural, electronic, and magnetic properties of these two perovskites. To that end, we first determined a suitable Hubbard parameter for the Co d–electrons to obtain a proper description of SmCoO{sub 3} that fully agrees with the available experimental data. We next evaluated the impact of oxygen and cation vacancies on the geometry, electronic, and magnetic properties. Oxygen vacancies strongly alter the electronic and magnetic structures of SmCoO{sub 3}, but barely affect LaMnO{sub 3}. However, due to their high formation energy, their concentrations in the material are very low and need to be induced by doping. Studying the cation vacancy concentration showed that the formation of cation vacancies is less energetically favorable than oxygen vacancies and would thus not markedly influence the performance of the cathode.

Tracking Oxygen Vacancies in Thin Film SOFC Cathodes

Science.gov (United States)

Leonard, Donovan; Kumar, Amit; Jesse, Stephen; Kalinin, Sergei; Shao-Horn, Yang; Crumlin, Ethan; Mutoro, Eva; Biegalski, Michael; Christen, Hans; Pennycook, Stephen; Borisevich, Albina

2011-03-01

Oxygen vacancies have been proposed to control the rate of the oxygen reduction reaction and ionic transport in complex oxides used as solid oxide fuel cell (SOFC) cathodes [1,2]. In this study oxygen vacancies were tracked, both dynamically and statically, with the combined use of scanned probe microscopy (SPM) and scanning transmission electron microscopy (STEM). Epitaxial films of La 0.8 Sr 0.2 Co O3 (L SC113) and L SC113 / LaSrCo O4 (L SC214) on a GDC/YSZ substrate were studied, where the latter showed increased electrocatalytic activity at moderate temperature. At atomic resolution, high angle annular dark field STEM micrographs revealed vacancy ordering in L SC113 as evidenced by lattice parameter modulation and EELS studies. The evolution of oxygen vacancy concentration and ordering with applied bias and the effects of bias cycling on the SOFC cathode performance will be discussed. Research is sponsored by the of Materials Sciences and Engineering Division, U.S. DOE.

Perforated peptic ulcer in an infant.

Science.gov (United States)

Feng, C Y; Hsu, W M; Chen, Y

2001-02-01

We describe a case of perforated peptic ulcer (PPU) in a 9-month-old boy. Abdominal distension was the first clinical sign of PPU. Before he developed abdominal distension, the patient had suffered from an upper respiratory tract infection with fever for about 2 weeks, which was treated intermittently with ibuprofen. A plain abdominal radiograph revealed pneumoperitoneum with a football sign. At laparotomy, a 0.8-cm perforated hole was found over the prepyloric area. Simple closure with omental patching was performed after debridement of the perforation. Pathologic examination showed chronic peptic ulcer with Helicobacter pylori infection. The postoperative course and outcome were satisfactory. The stress of underlying disease, use of ibuprofen, blood type (A), and H. pylori infection might have contributed to the development of PPU in this patient. PPU in infancy is rare and has a high mortality rate; early recognition and prompt surgical intervention are key to successful management.

Enhanced oxygen diffusion in low barium-containing La0.2175Pr0.2175Ba0.145Sr0.4Fe0.8Co0.2O3−δ intermediate temperature solid oxide fuel cell cathodes

KAUST Repository

Vert, Vicente B.

2012-09-01

Isotopic tracer diffusion studies have been performed on the perovskite composition La 0.2175Pr 0.2175Ba 0.145Sr 0.4Fe 0.8Co 0.2O 3-δ to obtain the diffusion and surface exchange coefficients for oxygen. This material has been identified as a highly active electrocatalytic cathode for intermediate temperature solid oxide fuel cells. The oxygen diffusion coefficients obtained in the 450-650 °C temperature range are higher than the ones measured for most of the cathode materials reported in the literature and they agree with those calculated from electrochemical impedance spectroscopy measurements performed on symmetrical cells. © 2012 Elsevier B.V. All rights reserved.

A case report of esophageal perforation: Complication of nasogastric tube placement

Science.gov (United States)

Isik, Arda; Firat, Deniz; Peker, Kemal; Sayar, Ilyas; Idiz, Oguz; Soytürk, Mehmet

2014-01-01

Patient: Male, 70 Final Diagnosis: Esophageal perforation Symptoms: Abdominal pain • nausea • vomiting Medication: — Clinical Procedure: — Specialty: Surgery Objective: Unusual clinical course Background: Esophageal perforation is a well-defined and severe clinical condition. There are several etiologies of esophagus perforation. Case Report: We report the case of a 70-year-old Caucasian man who underwent an emergency cholecystectomy due to acute cholecystitis. Two days after surgery, his condition deteriorated. Thorax computerized tomography revealed an esophageal perforation. Conclusions: Esophageal perforation due to nasogastric application is relatively rare but the consequences are potentially serious. The anatomy of the upper gastrointestinal system should be understood by all healthcare professionals involved in the treatment. PMID:24803977

Manufacturing of Electrolyte and Cathode Layers SOFC Using Atmospheric Spraying Method and Its Characterization

Directory of Open Access Journals (Sweden)

S. Sulistyo

2012-12-01

Full Text Available The use of Solid Oxide Fuel Cell (SOFC has created various interest in many parties, due to its capability to convert gases into electricity. The main requirement of SOFC cell components is to be produced as thin as possible to minimize the losses of electrical resistance, as well as able to support internal and external loads. This paper discusses the procedure of making a thin electrolyte layer, as well as a porous thin layer cathode using atmospheric spraying technique. The procedure of spraying was in room temperature with the process of sintering at temperature of 13500 C held for 3 hours. The SOFC characterization of electrolyte and cathode microstructure was determined by using the SEM, FESEM, XRD and impedance spectroscopy, to measure the impedance of SOFC cells. The results show that the thickness of thin layer electrolyte and porous cathode obtained of about 20 µm and 4 µm, respectively. Also the SOFC cell impedance was measured of 2.3726 x 106 Ω at room temperature. The finding also demonstrated that although the materials (anode, cathode and electrolyte possess different coefficient thermal expansion, there was no evidence of flaking layers which seen the materials remain intact. Thus, the atmospheric spraying method can offer an alternative method to manufacturing of SOFC thin layer electrolyte and cathode. [Key words: SOFC; spraying method; electrolyte; cathode

Gastrointestinal perforations in children: a continuing challenge to nonoperative treatment of blunt abdominal trauma.

Science.gov (United States)

Ulman, I; Avanoğlu, A; Ozcan, C; Demircan, M; Ozok, G; Erdener, A

1996-07-01

The present trend towards conservative management of hemodynamically stable pediatric trauma patients may be increasing the risk of delay in the diagnosis of traumatic hollow viscus perforations (HVP). The purpose of this study is to determine whether there is a delay in the diagnosis of HVP because of expectant management. A survey of factors leading to diagnostic delay was also made and the value of current diagnostic tools were reevaluated. In 1,283 trauma admissions between 1980-1994, 34 patients were operated for HVP caused by blunt abdominal trauma. Sites of perforation were; stomach (four), duodenum (five), jejunum (12), ileum (nine), and jejunum/ileum (four). Signs of peritoneal irritation were positive in 32 of 34 patients. There was free air in only six of 24 abdominal roentgenograms. Free peritoneal fluid without solid organ injury was detected in only four out of 13 patients with ultrasound. Peritoneal lavage was diagnostic in eight of nine patients. Time from admission to operating room averaged 24 +/- 4.1 (mean +/- standard deviation) hours. Eleven patients died after the operation mostly because of accompanying head injury. Only two of the deaths were the result of sepsis originating from the perforated bowel. There is an apparent delay in the diagnosis of traumatic HVP in this series. Signs of peritoneal irritation are the most consistent findings of HVP after blunt abdominal trauma in children. Persistence of abdominal signs indicates peritoneal lavage, which has a high diagnostic sensitivity for HVP compared to other diagnostic modalities.

Carbon nanotube growth on nanozirconia under strong cathodic polarization in steam and carbon dioxide

DEFF Research Database (Denmark)

Tao, Youkun; Ebbesen, Sune Dalgaard; Zhang, Wei

2014-01-01

nanozirconia acting as a catalyst for the growth of carbon nanotubes (CNTs) during electrochemical conversion of carbon dioxide and water in a nickel-yttria- stabilized zirconia cermet under strong cathodic polarization. An electrocatalytic mechanism is proposed for the growth of the CNTs. ${{{\\rm {\\rm V......Growth of carbon nanotubes (CNTs) catalyzed by zirconia nanoparticles was observed in the Ni-yttria doped zirconia (YSZ) composite cathode of a solid oxide electrolysis cell (SOEC) at approximately 875 °C during co-electrolysis of CO2 and H2O to produce CO and H 2. CNT was observed to grow under...

Perforate on CHO cell membranes induced by electromagnetic ...

African Journals Online (AJOL)

STORAGESEVER

2009-06-17

Jun 17, 2009 ... Key words: Electromagnetic pulse (EMP), atomic force microscope, CHO cell, cell membrane. INTRODUCTION .... of perforation ranges from 390 to 660 nm and the depth is. 392.95 nm. ... cell membrane perforations increased when both the field intensity and ..... Melatonin and a spin-trap compound block.

Perforated appendicitis: Risk factors and outcomes of management ...

African Journals Online (AJOL)

The case files of patients with perforated appendicitis were analysed in relation to age, sex, clinical presentation, management and outcome of management. The aim was to detect the main factors that contributed to the perforation of the appendix in these patients and assess the effectiveness of the treatment offered.

Color Doppler Ultrasonography-Targeted Perforator Mapping and Angiosome-Based Flap Reconstruction

DEFF Research Database (Denmark)

Gunnarsson, Gudjon Leifur; Tei, Troels; Thomsen, Jørn Bo

2016-01-01

Knowledge about perforators and angiosomes has inspired new and innovative flap designs for reconstruction of defects throughout the body. The purpose of this article is to share our experience using color Doppler ultrasonography (CDU)-targeted perforator mapping and angiosome-based flap reconstr......Knowledge about perforators and angiosomes has inspired new and innovative flap designs for reconstruction of defects throughout the body. The purpose of this article is to share our experience using color Doppler ultrasonography (CDU)-targeted perforator mapping and angiosome-based flap...

Optimizing time management after perforation by colonoscopy results in better outcome for the patients.

Science.gov (United States)

Rumstadt, Bernhard; Schilling, Dieter

2008-01-01

Perforation during colonoscopy is a rare but severe complication. The aim of this study was to assess the time management and laparoscopic therapy of this complication and to evaluate patient outcomes. A retrospective analysis was done on 15 patients operated for a perforation from colonoscopy between January 2000 and December 2006. Three perforations occurred during diagnostic and 12 perforations during interventional colonoscopy. Two perforations occurred as transmural thermal injury to the colon wall. Peritonitis was found in 4 cases and significantly correlated with the mean time between perforation and operation. Twelve perforations were oversewn laparoscopically and 3 perforations were oversewn by laparotomy. After laparoscopic treatment, hospital stay was significantly shorter than after laparotomy. One patient had a postoperative wound infection, mortality was 0%. Laparoscopic oversewing is a safe and effective method in the treatment of perforation from colonoscopy. Optimizing the time range between perforation and laparoscopic therapy results in a better outcome for the patients.

Bladder perforations in children

African Journals Online (AJOL)

2014-11-20

Nov 20, 2014 ... Mean recovery time for patients was 15 days. ... fracture.[1,2] Isolated bladder perforations are rare, and they .... PA, perineal injury, pelvic fracture. Trauma .... Lower genitourinary injury and pelvic fractures in pediatric patients.

Cathode materials review

Science.gov (United States)

Daniel, Claus; Mohanty, Debasish; Li, Jianlin; Wood, David L.

2014-06-01

The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403-431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead-acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide-hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J. Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783-789) demonstrated a high-energy and high-power LiCoO2 cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research.

Cathode materials review

International Nuclear Information System (INIS)

Daniel, Claus; Mohanty, Debasish; Li, Jianlin; Wood, David L.

2014-01-01

The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403-431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead-acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide-hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J. Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783-789) demonstrated a high-energy and high-power LiCoO 2 cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research

Cathode materials review

Energy Technology Data Exchange (ETDEWEB)

Daniel, Claus, E-mail: danielc@ornl.gov; Mohanty, Debasish, E-mail: danielc@ornl.gov; Li, Jianlin, E-mail: danielc@ornl.gov; Wood, David L., E-mail: danielc@ornl.gov [Oak Ridge National Laboratory, 1 Bethel Valley Road, MS6472 Oak Ridge, TN 37831-6472 (United States)

2014-06-16

The electrochemical potential of cathode materials defines the positive side of the terminal voltage of a battery. Traditionally, cathode materials are the energy-limiting or voltage-limiting electrode. One of the first electrochemical batteries, the voltaic pile invented by Alessandro Volta in 1800 (Phil. Trans. Roy. Soc. 90, 403-431) had a copper-zinc galvanic element with a terminal voltage of 0.76 V. Since then, the research community has increased capacity and voltage for primary (nonrechargeable) batteries and round-trip efficiency for secondary (rechargeable) batteries. Successful secondary batteries have been the lead-acid with a lead oxide cathode and a terminal voltage of 2.1 V and later the NiCd with a nickel(III) oxide-hydroxide cathode and a 1.2 V terminal voltage. The relatively low voltage of those aqueous systems and the low round-trip efficiency due to activation energies in the conversion reactions limited their use. In 1976, Wittingham (J. Electrochem. Soc., 123, 315) and Besenhard (J. Power Sources 1(3), 267) finally enabled highly reversible redox reactions by intercalation of lithium ions instead of by chemical conversion. In 1980, Goodenough and Mizushima (Mater. Res. Bull. 15, 783-789) demonstrated a high-energy and high-power LiCoO{sub 2} cathode, allowing for an increase of terminal voltage far beyond 3 V. Over the past four decades, the international research community has further developed cathode materials of many varieties. Current state-of-the-art cathodes demonstrate voltages beyond any known electrolyte stability window, bringing electrolyte research once again to the forefront of battery research.

Traumatic oesophageal perforation due to haematoma

DEFF Research Database (Denmark)

Grønhøj Larsen, Christian; Brandt, Bodil

2014-01-01

. Three explanations postulated to be the cause for late perforation which might be due to esophageal wall ischemia from pressure built up between the hematoma, azygos vein and the lower part of thoracic trachea; or could be an immediate rupture walled-off until the patient became symptomatic......; or the intramural hematoma gradually lysed and causing late perforation. CONCLUSION: Although extremely rare, an oesophageal haematoma and late complications must be considered in patients on anti-coagulant therapy following blunt thoracic trauma and complaining only of chest pain....

Carbon black as an alternative cathode material for electrical energy recovery and transfer in a microbial battery.

Science.gov (United States)

Zhang, Xueqin; Guo, Kun; Shen, Dongsheng; Feng, Huajun; Wang, Meizhen; Zhou, Yuyang; Jia, Yufeng; Liang, Yuxiang; Zhou, Mengjiao

2017-08-01

Rather than the conventional concept of viewing conductive carbon black (CB) to be chemically inert in microbial electrochemical cells (MECs), here we confirmed the redox activity of CB for its feasibility as an electron sink in the microbial battery (MB). Acting as the cathode of a MB, the solid-state CB electrode showed the highest electron capacity equivalent of 18.58 ± 0.46 C/g for the unsintered one and the lowest capacity of 2.29 ± 0.48 C/g for the one sintered under 100% N 2 atmosphere. The capacity vibrations of CBs were strongly in coincidence with the abundances of C=O moiety caused by different pretreatments and it implied one plausible mechanism based on CB's surface functionality for its electron capturing. Once subjected to electron saturation, CB could be completely regenerated by different strategies in terms of electrochemical discharging or donating electrons to biologically-catalyzed nitrate reduction. Surface characterization also revealed that CB's regeneration fully depended on the reversible shift of C=O moiety, further confirming the functionality-based mechanism for CB's feasibility as the role of MB's cathode. Moreover, resilience tests demonstrated that CB cathode was robust for the multi-cycles charging-discharging operations. These results imply that CB is a promising alternative material for the solid-state cathode in MBs.

Performance characteristics of a perforated shadow band under clear sky conditions

Energy Technology Data Exchange (ETDEWEB)

Brooks, Michael J. [School of Mechanical Engineering, University of KwaZulu-Natal, Durban (South Africa)

2010-12-15

A perforated, non-rotating shadow band is described for separating global solar irradiance into its diffuse and direct normal components using a single pyranometer. Whereas shadow bands are normally solid so as to occult the sensor of a pyranometer throughout the day, the proposed band has apertures cut from its circumference to intermittently expose the instrument sensor at preset intervals. Under clear sky conditions the device produces a saw tooth waveform of irradiance data from which it is possible to reconstruct separate global and diffuse curves. The direct normal irradiance may then be calculated giving a complete breakdown of the irradiance curves without need of a second instrument or rotating shadow band. This paper describes the principle of operation of the band and gives a mathematical model of its shading mask based on the results of an optical ray tracing study. An algorithm for processing the data from the perforated band system is described and evaluated. In an extended trial conducted at NREL's Solar Radiation Research Laboratory, the band coupled with a thermally corrected Eppley PSP produced independent curves for diffuse, global and direct normal irradiance with low mean bias errors of 5.6 W/m{sup 2}, 0.3 W/m{sup 2} and -2.6 W/m{sup 2} respectively, relative to collocated reference instruments. Random uncertainties were 9.7 W/m{sup 2} (diffuse), 17.3 W/m{sup 2} (global) and 19.0 W/m{sup 2} (direct). When the data processing algorithm was modified to include the ray trace model of sensor exposure, uncertainties increased only marginally, confirming the effectiveness of the model. Deployment of the perforated band system can potentially increase the accuracy of data from ground stations in predominantly sunny areas where instrumentation is limited to a single pyranometer. (author)

LiCoO.sub.2./sub. thin-film cathodes grown by RF sputtering

Czech Academy of Sciences Publication Activity Database

Prachařová, Jarmila; Přidal, Jiří; Bludská, Jana; Jakubec, Ivo; Vorlíček, Vladimír; Málková, Zuzana; Makris, D. T.; Giorgi, R.; Jastrabík, Lubomír

2002-01-01

Roč. 108, - (2002), s. 204-212 ISSN 0378-7753 R&D Projects: GA MŠk ME 305 Institutional research plan: CEZ:AV0Z1010914 Keywords : LiCoO 3 * thin-film cathodes * Li- ion batteries Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.777, year: 2002

Method for improved gas-solids separation

Science.gov (United States)

Kusik, C.L.; He, B.X.

1990-11-13

Methods are disclosed for the removal of particulate solids from a gas stream at high separation efficiency, including the removal of submicron size particles. The apparatus includes a cyclone separator type of device which contains an axially mounted perforated cylindrical hollow rotor. The rotor is rotated at high velocity in the same direction as the flow of an input particle-laden gas stream to thereby cause enhanced separation of particulate matter from the gas stream in the cylindrical annular space between the rotor and the sidewall of the cyclone vessel. Substantially particle-free gas passes through the perforated surface of the spinning rotor and into the hollow rotor, from where it is discharged out of the top of the apparatus. Separated particulates are removed from the bottom of the vessel. 4 figs.

Analytical modeling of injectivity decline in perforated wells; Modelagem analitica da perda de injetividade em pocos canhoneados

Energy Technology Data Exchange (ETDEWEB)

Gomes, Vanessa Limeira Azevedo; Santos, Adriano dos; Araujo, Juliana Aragao de [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

2012-07-01

During water injection, reductions of permeability (or formation damage) have been observed in many reservoirs, characterizing the injectivity decline. The permeability reduction exists due to the presence of solid and liquid particles in suspension, which are present in the water injected to be. Like this, during the development of projects for the oil production in the water management area, the phenomenon of injectivity decline must be studied, among other activities. This study includes the theoretical and practical modeling of the injectivity decline. The modeling includes different analytical models (empirical and semi-empirical) and laboratory tests, accordingly. Looking forward to this, a simulator based on the classic filtration theory of porous media was developed in order to prevent the injectivity decline within perforated wells. The formation damage caused during deep filtration and cake formation (after transition time) was included in the modeling of perforated wells; the effect of superposition of the diverse perforations was also considered. Besides that, the injectivity decline forecast was made based on well history data. The simulator allowed to forecast the injectivity decline during water injection showing a good adjustment of field history data, so it could be used to assist in the planning of injection wells stimulation. (author)

Processing of strontium-doped lanthanum manganite suspensions for cathode production of the solid oxide fuel cell; Processamento das suspensoes de manganito de lantanio dopado com estroncio para fabricacao do catodo da celula a combustivel de oxido solido

Energy Technology Data Exchange (ETDEWEB)

Chiba, R.; Vargas, R.A.; Andreoli, M.; Seo, E.S.M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais. Lab. de SOFC - Insumos e Componentes

2008-07-01

The ceramic material, strontium-doped lanthanum manganite (La{sub 0,85}Sr{sub 0,15}MnO{sub 3} - LSM), has been used as cathode in Solid Oxide Fuel Cells (SOFCs). The cathode attainment as component of the SOFCs has been studied for diverse routes of synthesis and thin films forming in Yttria-stabilized zirconia (ZrO{sub 2}/Y{sub 2}O{sub 3} - YSZ) electrolyte. In this work, the LSM was synthesized by the citrate technique and deposited in YSZ substrate using the forming technique wet powder spraying. Rheological studies of suspensions and chemical, physical and microstructural characterizations of LSM powders were made, aiming at the deposition for thin films formation until 50 mum. The half unit cells LSM/YSZ sintered were characterized by scanning electron microscopy, for verification of porosity and adherence. In this sense, this work is a contribution for production of porous cathode using the forming technique wet powder spraying in the SOFCs. (author)

Capacity extended bismuth-antimony cathode for high-performance liquid metal battery

Science.gov (United States)

Dai, Tao; Zhao, Yue; Ning, Xiao-Hui; Lakshmi Narayan, R.; Li, Ju; Shan, Zhi-wei

2018-03-01

Li-Bi based liquid metal batteries (LMBs) have attracted interest due to their potential for solving grid scale energy storage problems. In this study, the feasibility of replacing the bismuth cathode with a bismuth-antimony alloy cathode in lithium based LMBs is investigated. The influence of the Bi:Sb ratio on voltage characteristics is evaluated via the constant current discharge method and electrochemical titration. On observing the cross section of the electrode at various stages of discharge, it is determined that both Sb and Bi form solid intermetallics with Li on the cathode. Additionally, the addition of Bi not only reduces the melting temperature of the Bi:Sb intermetallic but also actively contributes to the electrode capacity. Thereafter, a Li|LiCl-LiF|Sb-Bi liquid metal battery with 3 A h nameplate capacity, assembled and cycled at 1 C rate, is found to possess a stable capacity for over 160 cycles. The overall performance of this battery is discussed in the context of cost effectiveness, energy and coulombic efficiencies.

The influence of cathode excavation of cathodic arc evaporator on thickness uniformity and erosion products angle distribution

Directory of Open Access Journals (Sweden)

D. V. Duhopel'nikov

2014-01-01

Full Text Available Cathodic arc evaporators are used for coating with functional films. Prolonged or buttend evaporators may be used for this purposes. In butt-end evaporator the cathode spots move continuously on the cathode work surface and evaporate cathode material. High depth excavation profile forms on the cathode work surface while the thick coating precipitation (tens or hundreds of microns. The cathode excavation profile is shaped like a “cup” with high walls for electrostatic discharge stabilization systems with axial magnetic fields. Cathode spots move on the bottom of the “cup”. It is very likely that high “cup” walls are formed as a result of lasting work time influence on the uniformity of precipitated films.In the present work the influence of excavation profile walls height on the uniformity of precipitated coating was carried out. The high profile walls are formed due to lasting work of DC vacuum arc evaporator. The cathode material used for tests was 3003 aluminum alloy. The extended substrate was placed parallel to the cathode work surface. Thickness distribution along the substrate length with the new cathode was obtained after 6 hours and after 12 hours of continuous operation.The thickness distribution of precipitated coating showed that the cathode excavation has an influence on the angular distribution of the matter escaping the cathode. It can be clearly seen from the normalized dependence coating thickness vs the distance from the substrate center. Also the angular distribution of the matter flow from the cathode depending on the cathode working time was obtained. It was shown that matter flow from the cathode differs from the LambertKnudsen law. The more the cathode excavation the more this difference.So, cathode excavation profile has an influence on the uniformity of precipitated coating and it is necessary to take in account the cathode excavation profile while coating the thick films.

A centre-triggered magnesium fuelled cathodic arc thruster uses sublimation to deliver a record high specific impulse

Science.gov (United States)

Neumann, Patrick R. C.; Bilek, Marcela; McKenzie, David R.

2016-08-01

The cathodic arc is a high current, low voltage discharge that operates in vacuum and provides a stream of highly ionised plasma from a solid conducting cathode. The high ion velocities, together with the high ionisation fraction and the quasineutrality of the exhaust stream, make the cathodic arc an attractive plasma source for spacecraft propulsion applications. The specific impulse of the cathodic arc thruster is substantially increased when the emission of neutral species is reduced. Here, we demonstrate a reduction of neutral emission by exploiting sublimation in cathode spots and enhanced ionisation of the plasma in short, high-current pulses. This, combined with the enhanced directionality due to the efficient erosion profiles created by centre-triggering, substantially increases the specific impulse. We present experimentally measured specific impulses and jet power efficiencies for titanium and magnesium fuels. Our Mg fuelled source provides the highest reported specific impulse for a gridless ion thruster and is competitive with all flight rated ion thrusters. We present a model based on cathode sublimation and melting at the cathodic arc spot explaining the outstanding performance of the Mg fuelled source. A further significant advantage of an Mg-fuelled thruster is the abundance of Mg in asteroidal material and in space junk, providing an opportunity for utilising these resources in space.

Nanostructured sulfur cathodes

KAUST Repository

Yang, Yuan

2013-01-01

Rechargeable Li/S batteries have attracted significant attention lately due to their high specific energy and low cost. They are promising candidates for applications, including portable electronics, electric vehicles and grid-level energy storage. However, poor cycle life and low power capability are major technical obstacles. Various nanostructured sulfur cathodes have been developed to address these issues, as they provide greater resistance to pulverization, faster reaction kinetics and better trapping of soluble polysulfides. In this review, recent developments on nanostructured sulfur cathodes and mechanisms behind their operation are presented and discussed. Moreover, progress on novel characterization of sulfur cathodes is also summarized, as it has deepened the understanding of sulfur cathodes and will guide further rational design of sulfur electrodes. © 2013 The Royal Society of Chemistry.

Perforation of the Esophagus Secondary to Insertion of Covered Wallstent Endoprostheses

International Nuclear Information System (INIS)

Farrugia, Mark; Morgan, Robert A.; Latham, Jennifer A.; Glynos, Michael; Mason, Robert C.; Adam, Andreas

1997-01-01

Perforation of the esophagus is a very rare complication of metallic esophageal stent insertion. Two cases are presented in which esophageal perforations were caused by the sharp ends of metallic stents impinging on the esophageal wall. In retrospect, both perforations might have been prevented by additional stent insertion

Effect of scandia doping method on the emission uniformity of scandate cathode with Sc{sub 2}O{sub 3}–W matrix

Energy Technology Data Exchange (ETDEWEB)

Wang, Jinshu, E-mail: wangjsh@bjut.edu.cn; Lai, Chen; Liu, Wei; Yang, Fan; Zhang, Xizhu; Cui, Yuntao; Zhou, Meiling

2013-09-01

Graphical abstract: Emission uniformity of the cathodes prepared by mechanical mixing (a) and spray drying method (b). - Highlights: • The emission uniformity of scandate cathodes has been quantitively obtained. • The nanoparticles on the cathode surface lead to the electric field enhancement. • The cathode prepared by spray drying method exhibits good emission uniformity. - Abstract: Scandia doped tungsten matrix dispenser cathodes were manufactured using scandia doped tungsten powder prepared by mechanical mixing, liquid–solid doping and a spray drying method. It is found the macrostructure of the cathode depended on the powder preparation method. The cathode prepared using the powder prepared by spray drying method had a homogenous and porous matrix characterized with grains with a diameter of less than 1 μm and with many nanoparticles distributing uniformly around these grains. The cathode with submicron structure and uniform distribution of scandia exhibited good emission uniformity. The emission uniformity ΔJ/J of the cathode prepared by spray drying method was 0.17, about 6 times lower than that of the cathode prepared by mechanical mixing method. The calculation results showed that the nanoparticles led to electric field enhancement. A Ba–Sc–O multilayer on the cathode surface and nanoparticles distributing mainly on W grains contributed to the emission property of the cathode.

The US findings of acute nonperforated and perforated appendicitis in children

International Nuclear Information System (INIS)

Bae, Jun Gi; Lee, Young Seok; Jung, Yoon Ho; Kim, Ji Hye; Lee, Woon Ki; Lee, Tae Hoon

1996-01-01

To analyse and interpret different sonographic findings in acute nonperforated and appendicitis. In 46 cases of acute appendicitis in children(26 girls, 20 boys) proven by surgery, sonographic findings were reviewed retrospectively. The findings of nonperforated and perforated appendicitis were analysed, focusing on the size, shape and echogenicity of the appendix, echo patterns of periappendiceal abscesses, mesenteric lymphadenopathy, and the prevalence of appendicolith. A noncompressible distended appendix was present in 18 of 21 patients with nonperforated appendicitis and in 13 of 25 patients with perforation. In 18 patients with nonperforated appendicitis, the average diameter of distended appendix was 8.6 mm ; target appearance was noted in 16 patients and loss of echogenic submucosa in two. In 13 patients with perforated appendicitis, the average diameter of appendix was 9.1 mm ; target appearance was noted in four patients and loss of echogenic submucosa in nine. Periappendiceal abscesses were present in 21 of 25 cases of perforated appendicitis, and the echogenicity of abscesses was mixed in 12 patients, hypoechogenic in eight, and hyperechogenic in one. Mesenteric lymphadenopathy was present in two of 21 patients with nonperforated appendicitis and in four of 25 with perforation. Appendicolith was detected on sonography in three of 25 patients with perforated appendicitis, but was found in seven patients during surgery. One patients with perforated appendicitis also had right side hydronephrosis. Sonographically false-negative results were obtained in six cases. A sonographic examination was useful to differenciate perforated and nonperforated appendicitis in children. Loss of echogenic submucosa in the distended appendix and periappendiceal abscess formation were important findings in diagnosis of perforated appendicitis

Esophageal perforation during or after conformal radiotherapy for esophageal carcinoma

International Nuclear Information System (INIS)

Chen Haiyan; Ma Xiumei; Ye Ming; Hou Yanli; Xie Huaying; Bai Yongrui

2014-01-01

The aim of this study was to analyze the risk factors and prognosis for patients with esophageal perforation occurring during or after radiotherapy for esophageal carcinoma. We retrospectively analyzed 322 patients with esophageal carcinoma. These patients received radiotherapy for unresectable esophageal tumors, residual tumors after operation, or local recurrence. Of these, 12 had radiotherapy to the esophagus before being admitted, 68 patients had concurrent chemoradiotherapy (CRT), and 18 patients had esophageal perforation after RT (5.8%). Covered self-expandable metallic stents were placed in 11 patients. Two patients continued RT after stenting and control of infection; one of these suffered a new perforation, and the other had a massive hemorrhage. The median overall survival was 2 months (0-3 months) compared with 17 months in the non-perforation group. In univariate analysis, the Karnofsky performance status (KPS) being ≤ 70, age younger than 60, T4 stage, a second course of radiotherapy to the esophagus, extracapsular lymph nodes (LN) involving the esophagus, a total dose > 100 Gy (biologically effective dose -10 ), and CRT were risk factors for perforation. In multivariate analysis, age younger than 60, extracapsular LN involving the esophagus, T4 stage, and a second course of radiotherapy to the esophagus were risk factors. In conclusion, patients with T4 stage, extracapsular LN involving the esophagus, and those receiving a second course of RT should be given particular care to avoid perforation. The prognosis after perforation was poor. (author)

Material and Energy Flows in the Production of Cathode and Anode Materials for Lithium Ion Batteries

Energy Technology Data Exchange (ETDEWEB)

Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; James, Christine [Michigan State Univ., East Lansing, MI (United States). Chemical Engineering and Materials Science Dept.; Gaines, Linda G. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Gallagher, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States). Chemical Sciences and Engineering Division

2014-09-30

The Greenhouse gases, Regulated Emissions and Energy use in Transportation (GREET) model has been expanded to include four new cathode materials that can be used in the analysis of battery-powered vehicles: lithium nickel cobalt manganese oxide (LiNi_0.4Co_0.2Mn_0.4O₂ [NMC]), lithium iron phosphate (LiFePO₄ [LFP]), lithium cobalt oxide (LiCoO₂ [LCO]), and an advanced lithium cathode (0.5Li₂MnO₃∙0.5LiNi_0.44Co_0.25Mn_0.31O₂ [LMR-NMC]). In GREET, these cathode materials are incorporated into batteries with graphite anodes. In the case of the LMR-NMC cathode, the anode is either graphite or a graphite-silicon blend. This report documents the material and energy flows of producing each of these cathode and anode materials from raw material extraction through the preparation stage. For some cathode materials, we considered solid state and hydrothermal preparation methods. Further, we used Argonne National Laboratory’s Battery Performance and Cost (BatPaC) model to determine battery composition (e.g., masses of cathode, anode, electrolyte, housing materials) when different cathode materials were used in the battery. Our analysis concluded that cobalt- and nickel-containing compounds are the most energy intensive to produce.

Material and Energy Flows in the Production of Cathode and Anode Materials for Lithium Ion Batteries

Energy Technology Data Exchange (ETDEWEB)

Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); James, Christine [Michigan State Univ., East Lansing, MI (United States); Gaines, Linda [Argonne National Lab. (ANL), Argonne, IL (United States); Gallagher, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States); Dai, Qiang [Argonne National Lab. (ANL), Argonne, IL (United States); Kelly, Jarod C. [Argonne National Lab. (ANL), Argonne, IL (United States)

2015-09-01

The Greenhouse gases, Regulated Emissions and Energy use in Transportation (GREET) model has been expanded to include four new cathode materials that can be used in the analysis of battery-powered vehicles: lithium nickel cobalt manganese oxide (LiNi_0.4Co_0.2Mn_0.4O₂ [NMC]), lithium iron phosphate (LiFePO₄ [LFP]), lithium cobalt oxide (LiCoO₂ [LCO]), and an advanced lithium cathode (0.5Li₂MnO₃∙0.5LiNi_0.44Co_0.25Mn_0.31O₂ [LMR-NMC]). In GREET, these cathode materials are incorporated into batteries with graphite anodes. In the case of the LMR-NMC cathode, the anode is either graphite or a graphite-silicon blend. Lithium metal is also an emerging anode material. This report documents the material and energy flows of producing each of these cathode and anode materials from raw material extraction through the preparation stage. For some cathode materials, we considered solid state and hydrothermal preparation methods. Further, we used Argonne National Laboratory’s Battery Performance and Cost (BatPaC) model to determine battery composition (e.g., masses of cathode, anode, electrolyte, housing materials) when different cathode materials were used in the battery. Our analysis concluded that cobalt- and nickel-containing compounds are the most energy intensive to produce.

Preparation of cathode materials for solid oxide solid fuel (SOFC) using gelatin; Preparacao de materiais catodicos para celulas a combustivel de oxido solido (SOFC) atraves do uso de gelatina

Energy Technology Data Exchange (ETDEWEB)

Silva, R.M.; Aquino, F. de M.; Macedo, D.A. de; Sa, A.M.; Galvao, G.O., E-mail: rinaldo_mendesa@hotmail.com [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil)

2016-07-01

Fuel cells are electrochemical devices that convert chemical energy into electrical energy. These devices are basically divided into interconnectors, electrolyte, anode, and cathode. Recently, studies of improvements in microstructural and morphological properties of calcium cobaltate (Ca{sub 3}Co{sub 4}O{sub 9}, C349) has been made regarding its potential use as SOFC cathode for intermediate temperature. Gelatin has proven to be effective as a polymerizing agent in the synthesis of nanocrystalline materials. This work reports the synthesis and characterization of the C349 cathode using commercial gelatin. The structural properties of the material were determined by X-ray diffraction (XRD). Morphological characterization was performed by scanning electron microscopy (SEM). The results showed the formation of the crystalline phase at 900 °C, indicating the effectiveness of the gelatin in the preparation of cathodes for SOFC. (author)

A CLINICAL STUDY ON PATIENTS WITH DUODENAL ULCER PERFORATION

Directory of Open Access Journals (Sweden)

Kishore Babu

2016-03-01

Full Text Available INTRODUCTION Perforated duodenal ulcer, the most catastrophic complication was Associated with high mortality in the past due to late presentation of the patients, delay in surgery and lack of antibiotics. Various authors state that the incidence of peptic ulcer disease and perforation has been declining for the past 3 decades. Because of advances in the medical therapy of peptic ulcer with a wide range of drugs the management of peptic ulcer disease has been changing and the role of surgery has been declining. Perforation is usually seen in 3rd and 4th decades with a male preponderance and the epidemiological trend is not the same worldwide. Incidence is slightly declining in western countries. The present study has been done during the period between 2013 and 2014 in S. V. R. R. Government general hospital Tirupati. AIMS AND OBJECTIVES The aim of the present study is to analyze the probable factors for increase in incidence of duodenal ulcer perforation, with particular emphasis on assessment of impact of H2 receptor antagonists and Proton Pump inhibitors on the incidence of perforation. STUDY SETTING S. V. Medical College, Department of General Surgery, Tirupati. STUDY PERIOD Patients attending S. V. Medical College, Department of General Surgery with perforation during the period from November 2013 to October 2014. INCLUSION CRITERIA Patients between age group of more than 14 years presenting with pain abdomen and who are diagnosed to have peritonitis due to duodenal ulcer perforation. EXCLUSION CRITERIA Patients with peritonitis due causes other than duodenal ulcer. STUDY METHOD Prospective Observational study among the selected patients. Total numbers of peptic ulcer cases that were admitted in this hospital and treated either medically or surgically were noted. The details of their clinical history and findings, investigation reports, operative findings, post-operative complications were recorded. Simple closure was performed for all the

Jejunal perforation by swallowed ibuprofen caplet | Njoku | Nigerian ...

African Journals Online (AJOL)

We present a case of jejunal perforation caused by an unusual foreign body, an ibuprofen caplet in its blister packing believed to be the first of its kind, perforation of the intestine caused by an ingested medication. The patient eventually developed an enterocutaneous fistula through the weak wall of a preexisting incisional ...

Novel quasi-symmetric solid oxide fuel cells with enhanced electrochemical performance

KAUST Repository

Chen, Yonghong

2016-02-16

Symmetrical solid oxide fuel cell (SSOFC) using same materials as both anode and cathode simultaneously has gained extensively attentions, which can simplify fabrication process, minimize inter-diffusion between components, enhance sulfur and coking tolerance by operating the anode as the cathode in turn. With keeping the SSOFC\\'s advantages, a novel quasi-symmetrical solid oxide fuel cell (Q-SSOFC) is proposed to further improve the performance, which optimally combines two different SSOFC electrode materials as both anode and cathode simultaneously. PrBaFe2O5+δ (PBFO) and PrBaFe1.6Ni0.4O5+δ (PBFNO, Fe is partially substituted by Ni.) are prepared and applied as both cathode and anode for SSOFC, which exhibit desirable chemical and thermal compatibility with Sm0.8Ce0.2O1.9 (SDC) electrolyte. PBFO cathode exhibits higher oxygen reduction reaction (ORR) activity than PBFNO cathode in air, whereas PBFNO anode exhibits higher hydrogen oxidation reaction (HOR) activity than PBFO anode in H2. The as-designed Q-SSOFC of PBFNO/SDC/PBFO exhibits higher electrochemical performance than the conventional SSOFCs of both PBFO/SDC/PBFO and PBFNO/SDC/PBFNO. The superior performance of Q-SSOFC is attributed to the lowest polarization resistance (Rp). The newly developed Q-SSOFCs open doors for further improvement of electrochemical performance in SSOFC, which hold more promise for various potential applications. © 2016 Elsevier B.V. All rights reserved.

Cause rare d'une perforation de la cloison nasale

Science.gov (United States)

Jahidi, Ali; Hemmaoui, Bouchaïb; Itoua, Wulfran Rosaire; Errami, Noureddine; Benariba, Fouad

2014-01-01

Les perforations de la cloison nasale constituent une pathologie fréquente en ORL. Leurs causes sont multiples et restent dominées par les traumatismes chirurgicaux. Les étiologies infectieuses et notamment la tuberculose sont rares. Nous présentons le cas d'une patiente ayant bénéficié d'une méatotomie bilatérale et chez laquelle une perforation de la cloison nasale a été découverte lors d'un examen systématique à un an de son intervention. D'abord considérée comme une complication de la chirurgie, la biopsie des berges de la perforation a permis de déterminer son origine tuberculeuse. La présentation clinique des perforations de la cloison nasale n'est pas spécifique. Elles sont souvent asymptomatiques et de découverte fortuite. Les traumatismes notamment chirurgicaux sont le plus siuvent en cause. L′orogine tuberculeuse resta très rare. Le diagnostic de certitude de tuberculose repose sur la biopsie des berges de cette perforation. Le but de ce travail est de mettre en avant l'intérêt de la biopsie dans le diagnostic de la tuberculose de la cloison nasale. Cette biopsie doit être systématique même en cas d'antécédents de chirurgie endonasale qui est le plus souvent en cause dans les perforations de la cloison nasale. PMID:24932334

The study of flow and proton exchange interactions in the cylindrical solid oxide fuel cell

CERN Document Server

Saievar-Iranizad, E

2002-01-01

The solid oxide fuel cell operates at high temperature of about 1000 deg C. In this temperature, some known materials such as Ni, ... which is abundant in the nature, can be used as a catalyst in the electrodes. The electrolytes of such cell solid oxide fuel cell can be made through non-porous solid ceramics such as Zircon's (ZrO sub 2). It can be stabilized using a doped Yttrium oxide. The importance of Yttria-stabilised Zirconia at high temperature belongs to the transport of oxygen ions through the electrolyte. Oxygen using in the hot cathode side causes a considerable reduction in the concentration of oxygen molecules. The oxygen ions exchange through the electrolyte relates to the molecular oxygen concentration gradient between the anode and cathode. Applying fuels such as hydrogen or natural gas in the anode and its chemical reaction with oxygen ions transfer from cathode through the electrolyte, produce electricity, water and heat. To study the ion exchange and its interaction into solid oxide fuel cel...

Reconstruction of pressure sores with perforator-based propeller flaps.

Science.gov (United States)

Jakubietz, Rafael G; Jakubietz, Danni F; Zahn, Robert; Schmidt, Karsten; Meffert, Rainer H; Jakubietz, Michael G

2011-03-01

Perforator flaps have been successfully used for reconstruction of pressure sores. Although V-Y advancement flaps approximate debrided wound edges, perforator-based propeller flaps allow rotation of healthy tissue into the defect. Perforator-based propeller flaps were planned in 13 patients. Seven pressure sores were over the sacrum, five over the ischial tuberosity, and one on the tip of the scapula. Three patients were paraplegic, six were bedridden, and five were ambulatory. In three patients, no perforators were found. In 10 patients, propeller flaps were transferred. In two patients, total flap necrosis occurred, which was reconstructed with local advancement flaps. In two cases, a wound dehiscence occurred and had to be revised. One hematoma required evacuation. No further complications were noted. No recurrence at the flap site occurred. Local perforator flaps allow closure of pressure sores without harvesting muscle. The propeller version has the added benefit of transferring tissue from a distant site, avoiding reapproximation of original wound edges. Twisting of the pedicle may cause torsion and venous obstruction. This can be avoided by dissecting a pedicle of at least 3 cm. Propeller flaps are a safe option for soft tissue reconstruction of pressure sores. © Thieme Medical Publishers.

Small bowel perforation due to fish bone: A case report

Directory of Open Access Journals (Sweden)

Huseyin Pulat

2015-09-01

Full Text Available Accidental ingestion of foreign bodies are a common condition in clinical practice. However, small bowel perforation which dues to ingestion foreign bodies has been rarely seen. In this article, we report a case of small bowel perforation which dues to ingestion foreign body. A 80-year-old female patient, presenting with complaints of acute abdomen, was admitted to the emergency department. She denied abdominal pain, nausea and vomiting. The patient had tenderness and defense on the right lower quadrant. Contrast enhanced abdominal computed tomography has been used on the patient's diagnosis. This revealed small bowel perforation due to the ingestion of foreign body. The patient was operated emergency. A microperforation due to fish bone was detected on the terminal ileum. The patient underwent debridement and primary repair. The patient was discharged postoperative 7th day without problem. Bowel perforation due to the ingestion of foreign bodies should be considered in the differential diagnosis of acute abdomen. Keywords: Foreign body, Small intestine, Perforation

Arcjet cathode phenomena

Science.gov (United States)

Curran, Francis M.; Haag, Thomas W.; Raquet, John F.

1989-01-01

Cathode tips made from a number of different materials were tested in a modular arcjet thruster in order to examine cathode phenomena. Periodic disassembly and examination, along with the data collected during testing, indicated that all of the tungsten-based materials behaved similarly despite the fact that in one of these samples the percentage of thorium oxide was doubled and another was 25 percent rhenium. The mass loss rate from a 2 percent thoriated rhenium cathode was found to be an order of magnitude greater than that observed using 2 percent thoriated tungsten. Detailed analysis of one of these cathode tips showed that the molten crater contained pure tungsten to a depth of about 150 microns. Problems with thermal stress cracking were encountered in the testing of a hafnium carbide tip. Post test analysis showed that the active area of the tip had chemically reacted with the propellant. A 100 hour continuous test was run at about 1 kW. Post test analysis revealed no dendrite formation, such as observed in a 30 kW arcjet lifetest, near the cathode crater. The cathodes from both this test and a previously run 1000 hour cycled test displayed nearly identical arc craters. Data and calculations indicate that the mass losses observed in testing can be explained by evaporation.

Perforated Duodenal Ulcer in a Young Child: An Uncommon Condition

Directory of Open Access Journals (Sweden)

Rohit Prasad Yadav

2009-04-01

Full Text Available Duodenal ulcer is an uncommonly diagnosed entity in children. H. pyloriinfection, blood group ‘O’ or secondary to medications like non steroidal anti-infl ammatory drugs (NSAID and corticosteroids or physiological stress in burns, head injury and mucosal ischemia are implicated as risk factors for their causation. The diagnosis is usually overlooked because of vague and variable symptoms and remote index of suspicion accounted for their low incidence in children. Undiagnosed or mistreated perforations may carry high morbidity and mortality. We report a successfully treated 41/2 year old male child who presented with features of perforation peritonitis and was incidentally found to have a perforated duodenal ulcer. Key Words: duodenal ulcer, laparotomy, perforation

Perforated choledochal cyst in a Jehovah's Witness patient.

Science.gov (United States)

Jones, V S; Philip, C

2007-07-01

Perforation is a rare presentation of a choledochal cyst. The case reported is a 9-month-old female baby with a perforated choledochal cyst. Being a Jehovah's Witness, blood tranfusion was refused. Apart from highlighting this social dilemma, the suitability of a cystojejunostomy as a temporary measure in the above scenario is evaluated and discussed.

Gastric Perforation by Ingested Rabbit Bone Fragment

Directory of Open Access Journals (Sweden)

Giulio Gambaracci

2016-04-01

Full Text Available The majority of accidentally ingested foreign bodies is excreted from the gastrointestinal (GI tract without any complications. Sometimes sharp foreign bodies – like chicken and fish bones – can lead to intestinal perforation and may present insidiously with a wide range of symptoms and, consequently, different diagnoses. We report the case of a 59-year-old woman presenting with fever and a 1-month history of vague abdominal pain. Computed tomography (CT showed the presence of a hyperdense linear image close to the gastric antrum surrounded by a fluid collection and free peritoneal air. At laparotomy, a 4-cm rabbit bone fragment covered in inflamed tissue was detected next to a gastric wall perforation. Rabbit bone fragment ingestion, even if rarely reported, should not be underestimated as a possible cause of GI tract perforation.

An experimental investigation of cathode erosion in high current magnetoplasmadynamic arc discharges

Science.gov (United States)

Codron, Douglas A.

Since the early to mid 1960's, laboratory studies have demonstrated the unique ability of magnetoplasmadynamic (MPD) thrusters to deliver an exceptionally high level of specific impulse and thrust at large power processing densities. These intrinsic advantages are why MPD thrusters have been identified as a prime candidate for future long duration space missions, including piloted Mars, Mars cargo, lunar cargo, and other missions beyond low Earth orbit (LEO). The large total impulse requirements inherent of the long duration space missions demand the thruster to operate for a significant fraction of the mission burn time while requiring the cathodes to operate at 50 to 10,000 kW for 2,000 to 10,000 hours. The high current levels lead to high operational temperatures and a corresponding steady depletion of the cathode material by evaporation. This mechanism has been identified as the life-limiting component of MPD thrusters. In this research, utilizing subscale geometries, time dependent cathode axial temperature profiles under varying current levels (20 to 60 A) and argon gas mass flow rates (450 to 640 sccm) for both pure and thoriated solid tungsten cathodes were measured by means of both optical pyrometry and charged-coupled (CCD) camera imaging. Thoriated tungsten cathode axial temperature profiles were compared against those of pure tungsten to demonstrate the large temperature reducing effect lowered work function imparts by encouraging increased thermionic electron emission from the cathode surface. Also, Langmuir probing was employed to measure the electron temperature, electron density, and plasma potential near the "active zone" (the surface area of the cathode responsible for approximately 70% of the emitted current) in order to characterize the plasma environment and verify future model predictions. The time changing surface microstructure and elemental composition of the thoriated tungsten cathodes were analyzed using a scanning electron microscope

A rare manifestation of perforated diverticulitis: parastomal subcutaneous abscess.

NARCIS (Netherlands)

Peters, J.H.; Bleichrodt, R.P.; Goor, H. van

2003-01-01

Perforation is a serious complication of diverticular disease. The sigmoid is the main affected anatomic site of perforated diverticulitis and sigmoid resection followed either by Hartmann procedure or primary anastomosis are the standard surgical approaches. Surgery, however, does not cure

Delayed Diagnosis of Pharyngeal Perforation following Exploding Tyre Blast Barotrauma

Directory of Open Access Journals (Sweden)

Samantha M. Field

2014-01-01

Full Text Available Introduction. Pharyngoesophageal perforation secondary to barotrauma is a rare phenomenon that can have serious complications if identified late. It is challenging to detect due to nonspecific symptoms. We present a case in which detection proved difficult leading to delayed diagnosis. Case Report. A 27-year-old mechanic presented with haemoptysis, dysphonia, and odynophagia after a car tyre exploded in his face. Flexible nasoendoscopy (FNE revealed blood in the pharynx, thought to represent mucosal haemorrhage. Initial treatment consisted of IV dexamethasone and antibiotics. After 3 days, odynophagia persisted prompting a CT scan. This revealed a defect in the posterior hypopharynx and surgical emphysema in the deep neck tissues. Contrast swallow confirmed posterior hypopharyngeal leak. NG feeding was commenced until repeated contrast swallow confirmed resolution of the defect. Discussion. Prompt nonsurgical management of pharyngoesophageal perforation has good outcomes but untreated perforation can have serious complications. FNE should be performed routinely, but only a contrast swallow can diagnose a functional perforation. Clinicians should have a high index of clinical suspicion when patients present with barotrauma and odynophagia. Patients should be kept nil by mouth until perforation has been excluded. Conclusion. When faced with cases of facial barotrauma, clinicians should have a low threshold for further imaging to exclude pharyngoesophageal perforation.

The Impact of Strong Cathodic Polarization on SOC Electrolyte Materials

DEFF Research Database (Denmark)

Kreka, Kosova; Hansen, Karin Vels; Jacobsen, Torben

2016-01-01

One of the most promising reversible energy conversion/storage technologies is that of Solid Oxide Fuel/Electrolysis Cells (SOFC/SOEC, collectively termed SOC). Long term durability is typically required for such devises to become economically feasible, hence considerable amount of work has...... of impurities at the grain boundaries, electrode poisoning, delamination or cracks of the electrolyte etc., have been observed in cells operated at such conditions, lowering the lifetime of the cell1,2. High polarizations are observed at the electrolyte/cathode interface of an electrolysis cell operated at high...... current density. In case of a cell voltage above 1.6 V, p-type and n-type electronic conductivity are often observed at the anode and cathode respectively3. Hence, a considerable part of the current is lost as leakage through the electrolyte, thus lowering the efficiency of the cell considerably....

Laparoscopic lavage for perforated diverticulitis with purulent peritonitis

DEFF Research Database (Denmark)

Thornell, Anders; Angenete, Eva; Bisgaard, Thue

2016-01-01

Background: Perforated diverticulitis with purulent peritonitis has traditionally been treated with open colon resection and stoma formation with risk for reoperations, morbidity, and mortality. Laparoscopic lavage alone has been suggested as definitive treatment. Objective: To compare laparoscopic...... lavage with open colon resection and colostomy (Hartmann procedure) for perforated diverticulitis with purulent peritonitis. Design: Randomized, controlled, multicenter, open-label trial. (ISRCTN registry number: ISRCTN82208287) Setting: 9 hospitals in Sweden and Denmark. Patients: Patients who have...... confirmed Hinchey grade III perforated diverticulitis with purulent peritonitis at diagnostic laparoscopy. Intervention: Randomization between laparoscopic lavage and the Hartmann procedure. Measurements: Primary outcome was the percentage of patients having 1 or more reoperations within 12 months. Key...

Cr Poisoning On Nd2Ni0.95Cu0.05O4+δ Cathode for Solid Oxide Fuel Cells

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Choe Yeong-Ju

2016-06-01

Full Text Available In this study, Nd2Ni1-xCuxO4+δ (x=0, 0.05, 0.1, and 0.2 layered perovskite powders were synthesized by the glycine nitrate process (GNP and the chromium poisoning effect on the electrochemical performance of the Nd2Ni0.95Cu0.05O4+δ and La0.6Sr0.4Co0.2Fe0.8O3-δ cathodes were investigated. In the case of the LSCF cathode, the strontium chromite phase formed after the exposure of the gaseous chromium species, while there was no additional phase in the Nd2Ni0.95Cu0.05O4+δ cathode. The area specific resistance (ASR of the Nd2Ni0.95Cu0.05O4+δ cathode did not change significantly after the exposure of the gaseous chromium species at 800°C.

Transmural coil embolization—alternative technique for management of arterial perforation during subintimal angioplasty

Directory of Open Access Journals (Sweden)

Karthikeyan Damodharan

2016-01-01

Full Text Available Subintimal angioplasty of lower limb arterial occlusion carries a relatively higher risk of vessel perforation compared to transluminal angioplasty. Vessel perforation is a potentially life threatening complication which requires prompt recognition and management. They are usually managed by endovascular techniques such as low-pressure balloon tamponade, covered stents, and coil embolization of the ruptured artery. We describe a technique of treating vessel perforation following balloon angioplasty. Patient developed a large perforation of the proximal superficial femoral artery (SFA after balloon inflation during subintimal angioplasty of complete SFA occlusion. Following failure of balloon tamponade in sealing the perforation, we successfully treated it by deploying an embolization coil at the site of perforation through the vessel wall followed by balloon tamponade. Our technique could be a useful relatively inexpensive alternative treatment option in the management of vessel perforation compared to covered stents.

Solid lithium ion conductors for battery applications

Energy Technology Data Exchange (ETDEWEB)

Weppner, W.

1985-01-15

The phase equilibria and conductivities of the LiF-LiH, LiF-LiOH, LiF-Li/sub 2/O, Li/sub 2/S-Li/sub 2/O, Li/sub 2/S-LiCl and Li/sub 2/S-LiBr systems were investigated. All ternary single phases and two-phase mixtures are solid electrolytes which are thermodynamically stable in respect of reaction with elemental lithium (anode) and at practically useful, low lithium activities (cathode). The conductivity normally increases with decreasing thermodynamic stability and vice versa. The conductivity may be optimized in the case of solid solutions by selecting a composition with a decomposition voltage just above the value required by the cathode material employed. All materials are isotropic in structure and no dendrite formation was observed. This allows their use in rechargeable, thin film electrolyte batteries.

External perforated Solar Screens for daylighting in residential desert buildings: Identification of minimum perforation percentages

KAUST Repository

Sherif, Ahmed

2012-06-01

The desert climate is endowed by clear sky conditions, providing an excellent opportunity for optimum utilization of natural light in daylighting building indoor spaces. However, the sunny conditions of the desert skies, in countries like Egypt and Saudi Arabia, result in the admittance of direct solar radiation, which leads to thermal discomfort and the incidence of undesired glare. One type of shading systems that is used to permit daylight while controlling solar penetration is " Solar Screens" Very little research work addressed different design aspects of external Solar Screens and their influence on daylighting performance, especially in desert conditions, although these screens proved their effectiveness in controlling solar radiation in traditional buildings throughout history.This paper reports on the outcomes of an investigation that studied the influence of perforation percentage of Solar Screens on daylighting performance in a typical residential living room of a building in a desert location. The objective was to identify minimum perforation percentage of screen openings that provides adequate illuminance levels in design-specific cases and all-year-round.Research work was divided into three stages. Stage one focused on the analysis of daylighting illuminance levels in specific dates and times, while the second stage was built on the results of the first stage, and addressed year round performance using Dynamic Daylight Performance Metrics (DDPMs). The third stage addressed the possibility of incidence of glare in specific cases where illuminance levels where found very high in some specific points during the analysis of first stage. The research examined the daylighting performance in an indoor space with a number of assumed fixed experimentation parameters that were chosen to represent the principal features of a typical residential living room located in a desert environment setting.Stage one experiments demonstrated that the screens fulfilled the

Spectrum of perforation peritonitis in Pakistan: 300 cases Eastern experience

OpenAIRE

Ur-Rahman Shafiq; Malik Faiza; Afridi Shahida; Shamim Shahid; Samo Khursheed A

2008-01-01

Abstract Background Perforation peritonitis is the most common surgical emergency encountered by the surgeons all over the world as well in Pakistan. The spectrum of etiology of perforation peritonitis in tropical countries continues to differ from its western counter part. This study was conducted at Dow University of health sciences and Civil Hospital Karachi (DUHS & CHK) Pakistan, designed to highlight the spectrum of perforation peritonitis in the East and to improve its outcome. Methods ...

Exceptional Durability of Solid Oxide Cells

DEFF Research Database (Denmark)

Ebbesen, Sune; Mogensen, Mogens Bjerg

2010-01-01

Extensive efforts to resolve the degradation normally associated with solid oxide electrolysis cells (SOECs) have been conducted during the past decade. To date, the degradation is assumed to be caused by adsorption of impurities in the cathode, although no firm evidence for this degradation...

Uranium transport to solid electrodes in pyrochemical reprocessing of nuclear fuel

International Nuclear Information System (INIS)

Tomczuk, Z.; Ackerman, J.P.; Wolson, R.D.; Miller, W.E.

1992-01-01

A unique pyrochemical process developed for the separation of metallic nuclear fuel from fission products by electrotransport through molten LiCl-KCl eutectic salt to solid and liquid metal cathodes. The process allow for recovery and reuse of essentially all of the actinides in spent fuel from the integral fast reactor (IFR) and disposal of wastes in satisfactory forms. Electrotransport is used to minimize reagent consumption and, consequently, waste volume. In particular, electrotransport to solid cathodes is used for recovery of an essentially pure uranium product in the presence of other actinides; removal of pure uranium is used to adjust the electrolyte composition in preparation for recovery of a plutonium-rich mixture with uranium in liquid cadmium cathodes. This paper presents experiments that delineate the behavior of key actinide and rare-earth elements during electrotransport to a solid electrode over a useful range of PuCl 3 /UCl 3 ratios in the electrolyte, a thermodynamic basis for that behavior, and a comparison of the observed behavior with that calculated from a thermodynamic model. This work clearly established that recovery of nearly pure uranium can be a key step in the overall pyrochemical-fuel-processing strategy for the IFR

CLINICAL STUDY OF APPENDICULAR PERFORATION IN A TERTIARY CARE HOSPITAL

Directory of Open Access Journals (Sweden)

Venkata Anantha Lakshmi Manabala

2016-06-01

Full Text Available INTRODUCTION Acute Appendicitis is the commonest abdominal surgical emergency in young adults all over the world. In early 1900s, Ochsner in Chicago and Sherren at the London Hospital were both advocates of conservative treatment in late cases. Appendicular perforation is a serious complication in view of the ensuing peritonitis with the consequent sequelae and morbidity. AIM To study the incidence, morbidity and sequelae of appendicular perforation. MATERIALS & METHODS This is a prospective study done in our hospital where 110 cases of peritonitis due to appendicular perforation were selected for our study. All the cases where peritonitis was due to appendicular perforation at laparotomy were included. The study period was from January 2014 to December 2015. The cases of peritonitis due to other causes like duodenal, gastric, enteric perforation were excluded. Patients with acute abdominal emergency with clinical diagnosis of peritonitis were examined carefully with detailed history and clinical examination. Necessary investigations were done and patients taken up for emergency surgery. CONCLUSIONS Acute Appendicitis is the commonest abdominal surgical emergency in young adults all over the world. Age incidence of appendicular perforation is maximum in the age group of 21–30 years. Next common age group is 31–40 yrs. Incidence is more in males. Male to female ratio is 2.4:1. Pain abdomen, vomiting, fever and anorexia were common symptoms in all the patients. Majority of the patients came late to the hospital accounting for the cause of perforation and subsequent mortality and morbidity.

Electrochemical performance of LiNi0.5Mn1.5O4 prepared by improved solid state method as cathode in hybrid supercapacitor

International Nuclear Information System (INIS)

Wu Huiming; Rao, Ch. Venkateswara; Rambabu, B.

2009-01-01

The electrochemical performance of a hybrid asymmetric supercapacitor with activated carbon (AC) as anode and a lithium-ion intercalated compound LiNi 0.5 Mn 1.5 O 4 as cathode was studied. By using metal acetate precursors as starting materials in solid state reaction method, pure LiNi 0.5 Mn 1.5 O 4 was formed at low temperature. The role of precursors on the formation of material at low temperature and short period of time is presented. XRD confirms the cubic spinel structure (space group, Fd3m) and SEM shows the particles of size around 1 μm. The effect of the modified solid state reaction route on the structural and electrochemical properties was investigated. The fabricated hybrid supercapacitor, AC/LiNi 0.5 Mn 1.5 O 4 in a non-aqueous electrolyte 1.0 M LiPF 6 /EC-DMC exhibits a sloping voltage profile from 1.0 to 3.0 V and delivers a specific energy of ca. 56 Wh kg -1 . Moreover, it exhibits excellent cycling performance with less than 5% capacity loss over 1000 cycles.

Comparative study on experiments and simulation of blended cathode active materials for lithium ion batteries

International Nuclear Information System (INIS)

Appiah, Williams Agyei; Park, Joonam; Van Khue, Luu; Lee, Yunju; Choi, Jaecheol; Ryou, Myung-Hyun; Lee, Yong Min

2016-01-01

We simulate the electrochemical properties of Li-ion cells consisting of a blended cathode composed of LiMn 2 O 4 and LiNi 0.6 Co 0.2 Mn 0.2 O 2 and an artificial graphite anode using the Li-ion battery model available in COMSOL MULTIPHYSICS 4.4 along with a capacity fade model. The discharge profiles of the pure and blended cathodes at various current rates obtained through simulations and experimental results are well matched. By combining two capacity fade models available in literature, namely the solid electrolyte interphase (SEI) growth model and the Mn 2+ dissolution model, the cycling performance of the pure LiMn 2 O 4 cells at 25 °C are successfully simulated and found to be in a good agreement with the experimental results. The blended cathode exhibits better capacity retention than the pure LiMn 2 O 4 during cycling. We also observed that at high powers, the gravimetric energy density of the LiMn 2 O 4 cathode exceeds that of the LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode; the reverse effect is seen at low powers. Further, we were able to easily modulate the energy and power densities of the blended cathode system by changing the blend ratio in our simulation model.

The research progress of acute small bowel perforation

Directory of Open Access Journals (Sweden)

Rudolf Schiessel

2015-08-01

Full Text Available This article reviews the various aetiologies of small bowel perforations and their management. In addition to the well-known aetiologies such as trauma, inflammation and circulatory disorders, several new causes of small bowel perforation have been described in recent years. The spectrum reaches from iatrogenic perforations during laparoscopic surgery or enteroscopies to drug-induced perforations with new anticancer agents. The management of small bowel perforations requires a concept consisting of the safe revision of the leaking bowel and the treatment of the peritonitis. Depending on the local situation and the condition of the patient, several treatment options are available. The surgical management of the bowel leak can range from a simple primary closure to a delayed restoration of bowel continuity. When the condition of the bowel or patient is frail, the risk of a failure of a closure or anastomosis is too high, and the exteriorization of the bowel defect as a primary measure is a safe option. The treatment of the peritonitis is also dependent on the condition of the patient and the local situation. Early stages of peritonitis can be treated by a simple peritoneal lavage, either performed by laparoscopy or laparotomy. Severe forms of peritonitis with multi-organ failure and an abdominal compartment syndrome need repeated peritoneal revisions. In such cases, the abdomen can only be closed temporarily. Different technical options are available in order to overcome the difficult care of these patients.

Emission property of scandia and Re doped tungsten matrix dispenser cathode

International Nuclear Information System (INIS)

Wang Jinshu; Wang Yanchun; Liu Wei; Li Lili; Wang Yiman; Zhou Meiling

2008-01-01

Scandia and rhenium doped tungsten powders have been prepared by solid-liquid doping combined with two-step reduction method. The experimental results show that scandia distributes evenly in the doped tungsten powder. Moreover, the addition of scandia and rhenium could decrease the particle size of tungsten. By using this kind of powder, scandia and rhenium doped tungsten matrix with sub-micrometer sized tungsten grains and a uniform distribution of Sc 2 O 3 together with high pore density has been obtained. The emission property result shows that high space charge limited current density of more than 30 A/cm 2 at 850 deg. C has been obtained for this cathode. This excellent emission capability results from an active layer uniformly covering the sub-micron structure framework of the cathodes

A cobalt-free perovskite-type La{sub 0.6}Sr{sub 0.4}Fe{sub 0.9}Cr{sub 0.1}O{sub 3-{alpha}} cathode for proton-conducting intermediate temperature solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Ding, Zuolong; Yang, Zhijie; Zhao, Dongmei; Deng, Xuli [Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Ma, Guilin, E-mail: 32uumagl@suda.edu.cn [Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China)

2013-02-15

Highlights: Black-Right-Pointing-Pointer A cobalt-free cathode material LSFC10 for IT-SOFCs was prepared and studied in detail. Black-Right-Pointing-Pointer The conductivity of LSFC10 reached 138 S cm{sup -1} under oxygen at 550 Degree-Sign C. Black-Right-Pointing-Pointer An anode-supported BZCY electrolyte membrane was successfully fabricated by a simple spin coating process. Black-Right-Pointing-Pointer Power density of the ceramic membrane fuel cell using LSFC10 as cathode reached 412 mW cm{sup -2} at 700 Degree-Sign C. - Abstract: A cobalt-free perovskite-type cathode material La{sub 0.6}Sr{sub 0.4}Fe{sub 0.9}Cr{sub 0.1}O{sub 3-{alpha}} (LSFC10) was prepared by a citric acid-nitrate process and investigated as a potential cathode material for proton-conducting intermediate-temperature solid oxide fuel cells (IT-SOFCs). The maximum conductivity of LSFC10 reached 138 S cm{sup -1} under oxygen at 550 Degree-Sign C. A Ni-BZCY composite anode-supported proton-conducting BaZr{sub 0.1}Ce{sub 0.7}Y{sub 0.2}O{sub 3-{alpha}} (BZCY) electrolyte membrane was successfully fabricated by a simple, cost-effective spin coating process. The peak power densities of the H{sub 2}/O{sub 2} fuel cell using BZCY electrolyte membrane, Ni-BZCY composite anode and LSFC10 cathode reached 412 mW cm{sup -2}, and the interfacial polarization resistance for the fuel cell was as low as 0.19 {Omega} cm{sup 2} under open circuit conditions, at 700 Degree-Sign C. These results reveal LSFC10 is a suitable cathode material for proton-conducting IT-SOFCs.

Analysis of colonoscopic perforations at a local clinic and a tertiary hospital.

Science.gov (United States)

Sagawa, Toshihiko; Kakizaki, Satoru; Iizuka, Haruhisa; Onozato, Yasuhiro; Sohara, Naondo; Okamura, Shinichi; Mori, Masatomo

2012-09-21

To define the clinical characteristics, and to assess the management of colonoscopic complications at a local clinic. A retrospective review of the medical records was performed for the patients with iatrogenic colon perforations after endoscopy at a local clinic between April 2006 and December 2010. Data obtained from a tertiary hospital in the same region were also analyzed. The underlying conditions, clinical presentations, perforation locations, treatment types (operative or conservative) and outcome data for patients at the local clinic and the tertiary hospital were compared. A total of 10  826 colonoscopies, and 2625 therapeutic procedures were performed at a local clinic and 32  148 colonoscopies, and 7787 therapeutic procedures were performed at the tertiary hospital. The clinic had no perforations during diagnostic colonoscopy and 8 (0.3%) perforations were determined to be related to therapeutic procedures. The perforation rates in each therapeutic procedure were 0.06% (1/1609) in polypectomy, 0.2% (2/885) in endoscopic mucosal resection (EMR), and 3.8% (5/131) in endoscopic submucosal dissection (ESD). Perforation rates for ESD were significantly higher than those for polypectomy or EMR (P hospital. Six perforations occurred with therapeutic endoscopy (perforation rate, 0.08%; 1 per 1298 procedures). Perforation rates for specific procedure types were 0.02% (1 per 5500) for polypectomy, 0.17% (1 per 561) for EMR, 2.3% (1 per 43) for ESD in the tertiary hospital. There were no differences in the perforation rates for each therapeutic procedure between the clinic and the tertiary hospital. The incidence of iatrogenic perforation requiring surgical treatment was quite low in both the clinic and the tertiary hospital. No procedure-related mortalities occurred. Performing closure with endoscopic clipping reduced the C-reactive protein (CRP) titers. The mean maximum CRP titer was 2.9 ± 1.6 mg/dL with clipping and 9.7 ± 6.2 mg/dL without clipping

Perforated peptic ulcer in southeastern Taiwan.

Science.gov (United States)

Li, Chin-Hsien; Chang, Wen-Hsiung; Shih, Shou-Chuan; Lin, Shee-Chan; Bair, Ming-Jong

2010-09-01

No studies focus on the population with perforated peptic ulcer in southeastern Taiwan. The present study aimed to assess the differences between the different races and the risk factors related to mortality and morbidity in postoperative patients in southeastern Taiwan. The medical records of 237 patients were reviewed retrospectively. The following factors were analyzed: patient profiles, coexisting illnesses, diagnostic method, fever, preoperative shock, clinical data at emergency room, delay operation, site of perforation, operative method, positive ascites culture, species of microbes in ascites culture, postoperative complications, death and the length of hospital stay. Aborigines were significantly different from non-aborigines in the ratio of female cases and in the habits of alcohol drinking and betel nut chewing. There were also four significantly different variables between them: fever, hemoglobin value, site of perforation and operative method. Total postoperative complication rate was 41.3% and 39 patients (16.6%) died. In multivariate analysis, age > or = 65 years, lipase > upper normal limit and preoperative shock were independent predictors of mortality. Significant risk factors associated with morbidity were NSAIDs use, creatinine > 1.5 mg/dL and preoperative shock. Aborigines were different from non-aborigines in several categories. In southeastern Taiwan, NSAIDs use, creatinine > 1.5 mg/dL and preoperative shock were independent risk factors of morbidity, and age > or = 65 years, lipase > upper normal limit and preoperative shock were independent risk factors of mortality in postoperative perforated peptic ulcer. Lipase > upper normal limit is needed for further research on the influence on mortality.

Case report: Stercoral sigmoid colonic perforation with fecal peritonitis

International Nuclear Information System (INIS)

Sharma, Monika; Agrawal, Anjali

2010-01-01

Chronic constipation can lead to fecal impaction. It can also rarely lead to catastrophic complications like perforation, colonic obstruction, and fecal peritonitis. We report a rare case of stercoral sigmoid colonic perforation with fecal peritonitis and pneumoperitoneum, which was diagnosed on preoperative CT scan

Generalized multiscale finite element methods for problems in perforated heterogeneous domains

KAUST Repository

Chung, Eric T.

2015-06-08

Complex processes in perforated domains occur in many real-world applications. These problems are typically characterized by physical processes in domains with multiple scales. Moreover, these problems are intrinsically multiscale and their discretizations can yield very large linear or nonlinear systems. In this paper, we investigate multiscale approaches that attempt to solve such problems on a coarse grid by constructing multiscale basis functions in each coarse grid, where the coarse grid can contain many perforations. In particular, we are interested in cases when there is no scale separation and the perforations can have different sizes. In this regard, we mention some earlier pioneering works, where the authors develop multiscale finite element methods. In our paper, we follow Generalized Multiscale Finite Element Method (GMsFEM) and develop a multiscale procedure where we identify multiscale basis functions in each coarse block using snapshot space and local spectral problems. We show that with a few basis functions in each coarse block, one can approximate the solution, where each coarse block can contain many small inclusions. We apply our general concept to (1) Laplace equation in perforated domains; (2) elasticity equation in perforated domains; and (3) Stokes equations in perforated domains. Numerical results are presented for these problems using two types of heterogeneous perforated domains. The analysis of the proposed methods will be presented elsewhere. © 2015 Taylor & Francis

Colonic perforation with peritonitis in amoebiasis: a tropical disease with high mortality.

Science.gov (United States)

Jain, Bhupendra Kumar; Garg, Pankaj Kumar; Kumar, Anjay; Mishra, Kiran; Mohanty, Debajyoti; Agrawal, Vivek

2013-01-01

Invasive colonic amoebiasis presents primarily with dysentery; colonic perforation occurs rarely. Cases of amoebic colonic perforations have been reported sporadically over the past 20 years. A retrospective study was done in the surgical unit of a tertiary care hospital in North India. The case records of those patients were reviewed who underwent exploratory laparotomy from January 2011 to September 2012 and were diagnosed with amoebic colonic perforation on histopathological examination. Details concerning the clinical presentation, investigations, intraoperative findings, operative procedures, and postoperative outcomes were retrieved. Amongst, a total of 186 emergency exploratory laparotomies carried out during the study, 15 patients of amoebic colonic perforation were identified. The median age of the patients was 42 years (IQR 32.0-58.0) and the male to female ratio was 13:2. Previous history of colitis was present in only 1 patient. The preoperative diagnosis was perforation peritonitis in 12 patients; and intussusception, intestinal obstruction and ruptured liver abscess in 1 patient each. Ten patients had single perforation while 5 had multiple colonic perforations. All the patients except one had perforations in the right colon. Bowel resection was performed depending upon the site and extent of the colon involved-right hemicolectomy (8), limited ileocolic resection (6) and sigmoidectomy (1). Bowel continuity could be restored only in 2 of the 15 patients and a stoma was constructed in the remaining 13 patients. The overall mortality rate was found to be 40% (6/15). Amoebic colonic perforation is associated with unusually high mortality.

[Laparoscopic surgery for perforated peptic ulcer].

Science.gov (United States)

Yasuda, Kazuhiro; Kitano, Seigo

2004-03-01

Laparoscopic surgery has become the treatment of choice for the management of perforated peptic ulcer. The advantages of laparoscopic repair for perforated peptic ulcer include less pain, a short hospital stay, and an early return to normal activity. Although the operation time of laparoscopic surgery is significantly longer than that of open surgery, laparoscopic technique is safe, feasible, and with morbidity and mortality comparable to that of the conventional open technique. To benefit from the advantages offered by minimally invasive laparoscopic technique, further study will need to determine whether laparoscopic surgery is safe in patients with generalized peritonitis or sepsis.

Effect of ‘A’-site non stoichiometry in strontium doped lanthanum ferrite based solid oxide fuel cell cathodes

Energy Technology Data Exchange (ETDEWEB)

Banerjee, Koyel; Mukhopadhyay, Jayanta, E-mail: jayanta_mu@cgcri.res.in; Barman, Madhurima; Basu, Rajendra N., E-mail: rnbasu@cgcri.res.in

2015-12-15

Highlights: • La{sub 1−x}Sr{sub x}Co{sub y}Fe{sub 1−y}O{sub 3−δ}, x = 0.4; y = 0.2 system varying La-site (0.6–0.54) are studied. • Combustion synthesis technique is used to prepare the powder samples. • Highest electrical conductivity observed with largest A-site deficit composition. • Lowest cathode polarization is found with the same composition (0.02 Ω cm{sup 2}). • Composition with largest A-site deficiency exhibits best performance (2.84 A cm{sup −2}). - Abstract: Effect of A-site non-stoichiometry in strontium doped lanthanum cobalt ferrite (La{sub 1−x}Sr{sub x}Co{sub y}Fe{sub 1−y}O{sub 3−δ}, x = 0.4; y = 0.2) is studied in a systematic manner with variation of ‘A’ site stoichiometry from 1 to 0.94. The perovskite based cathode compositions are synthesized by combustion synthesis. Powder characterizations reveal rhombohedral crystal structure with crystallite size ranging from 29 to 34 nm with minimum lattice spacing of 0.271 nm. Detailed sintering studies along with total DC electrical conductivities are evaluated in the bulk form with variation of sintering temperatures. The electrode polarizations are measured in the symmetric cell configuration by impedance spectroscopy which is found to be the lowest (0.02 Ω cm{sup 2} at 800 °C) for cathode having highest degree of ‘A’-site deficiency. The same cathode composition exhibits a current density of 2.84 A cm{sup −2} (at 0.7 V, 800 °C) in anode-supported single cell. An attempt has been made to correlate the trend of electrical behaviour with increasing ‘A’-site deficiency for such cathode compositions.

Perforated Meckel's diverticulum in omphalocele

OpenAIRE

Jin, Hanna; Han, Ji-Won; Oh, Chaeyoun; Kim, Hyun-Young; Jung, Sung-Eun

2017-01-01

Meckel's diverticulum is a rare condition in neonates with reports of concurrent Meckel's diverticulum and omphalocele being few. Herein, we present a case of omphalocele associated with perforated Meckel's diverticulum.