The development of novel high-performance cathodes is essential to reduce Solid Oxide Fuel Cell (SOFCs) operation to low and intermediate temperatures. To that end, the performance of CeO 2 -based composite cathodes i...
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The development of novel high-performance cathodes is essential to reduce Solid Oxide Fuel Cell (SOFCs) operation to low and intermediate temperatures. To that end, the performance of CeO 2 -based composite cathodes is very attractive. In the present work, LSM (La0.8 Sr0.2 MnO3 ), LSCF (La0.5Sr0.5Co0.8Fe0.2O3 ) and SDC (Ce0.8Sm0.2O1.9 ) powders were synthesized by different synthesis methods and used to prepare SOFC composite film cathodes. LSM-SDC and LSCF-SDC composite powders were obtained by milling. Composite films were deposited onto yttria stabilized zirconia (YSZ) electrolytes and characterized by scanning electron microscopy. Preliminary performance tests were carried out using a single cell having a LSCF-SDC cathode. I-V curves indicated that the cell had qualitatively good performance with maximum power density of 19 mW/cm 2 at 800℃. The preparation of LSM and LSCF composites by mixing SDC, synthesized by the method proposed herein is an innovative alternative for the production of high performance ceramic materials for SOFC cathodes.
The agro and industrial activities are currently responsible for the production of large amounts of solid wastes. The use of industrial wastes such as granite, marble, kaolin and pegmatite and agro-industrial rejects ...
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The agro and industrial activities are currently responsible for the production of large amounts of solid wastes. The use of industrial wastes such as granite, marble, kaolin and pegmatite and agro-industrial rejects into clay products has been widely developed over the last few decades. Clay materials used in the ceramic industry exhibit a large diversification of compositions that al-low the addition of different types of waste materials to the clay mixture. Sugar cane bagasse ash (SCBA), a by-product of the sugar process, is exacerbating the environmental problem. Bra-zil produces an enormous amount of sugar and the lack of adequate landfill areas available for disposal of sugar cane bagasse ash rejects poses a critical problem for the agro-industry. This work describes, for the first time, research carried out on the manufacturing of ceramic tile mate-rials with sugar cane bagasse ash additions. SCBA, consisting basically of potassium oxide, was added to the clay formulations as an alternative to feldspar. Clay with different sugar cane ba-gasse ash content was mixed and sintered. Sintered specimens were characterized by X-ray dif-fraction, density, porosity, thermal analysis and strength measurements. The results obtained showed that the sugar cane ash residue can be added to clay materials as an alternative to feld-spar, without degrading their properties.
The objective of this work is to evaluate the ability of Mn-Ti substituted barium-strontium hexaferrite to absorb high frequency electromagnetic wave. To accomplish this objective, Mn-Ti substituted barium strontium h...
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We investigate evaporative lithography as a route for patterning colloidal films. Films are dried beneath a mask that induces periodic variations between regions of free and hindered evaporation. Direct imaging reveal...
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We investigate evaporative lithography as a route for patterning colloidal films. Films are dried beneath a mask that induces periodic variations between regions of free and hindered evaporation. Direct imaging reveals that particles segregate laterally within the film, as fluid and entrained particles migrate towards regions of higher evaporative flux. The films exhibit remarkable pattern formation that can be regulated by tuning the initial suspension composition, separation distance between the mask and underlying film, and mask geometry.
The plastic deformation of seven 5083 commercial aluminum materials, produced from five different alloy heats, are evaluated under conditions of interest for superplastic and quick-plastic forming. Two mechanisms are ...
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The plastic deformation of seven 5083 commercial aluminum materials, produced from five different alloy heats, are evaluated under conditions of interest for superplastic and quick-plastic forming. Two mechanisms are shown to govern plastic deformation in AA5083 over the strain rates, strains, and temperatures of interest for these forming technologies: grain-boundary-sliding (GBS) creep and solute-drag (SD) creep. Quantitative analysis of stress transients following rate changes clearly differentiates between GBS and SD creep and offers conclusive proof that SD creep dominates deformation at fast strain rates and low temperature. Furthermore, stress transients following strain-rate changes under SD creep are observed to decay exponentially with strain. A new graphical construction is proposed for the analysis and prediction of creep transients. This construction predicts the relative size of creep transients under SD creep from the relative size of changes in an applied strain rate or stress. This construction reveals the relative size of creep transients under SD creep to be independent of temperature;temperature dependence resides in the "steady-state" creep behavior to which transients are related.
作者：
HELLER, S.R.FIORITI, IVOVASTA, JOHNCaptain Heller
an Engineering Duty Officer of the United States Navy received his undergraduate education at the University of Michigan in Naval Architecture and Marine Engineering and in Mathematics. Following typical shipyard duty during World War II he received postgraduate instruction at the Massachusetts Institute of Technology leading to the degrees of Naval Engineer and Doctor of Science in Naval Architecture. Since then he has had design responsibilities in the Bureau of Ships had a maintenance assignment with the Fleet directed structural research at the David Taylor Model Basin engaged in submarine design and construction at Portsmouth Naval Shipyard and is now Head of Hull Design in the Bureau of Ships. Captain Heller is a member of ASNE SNAME Tau Beta Pi and Sigma Xi. Mr. Fioriti is the Materials Engineer in the Hull Scientific and Research Section
Bureau of Ships with responsibility for materials and fabrication processes that are used in the construction of ship hulls. Mr. Fioriti attended the University of Pittsburgh receiving the Bachelor of Science degree in Metallurgical Engineering in 1951. He took postgraduate work at the University of Maryland receiving the Master of Science degree in 1960. From 1951 to 1956 he worked in the Metals and Metallurgy Section of the Bureau of Ships where he planned and administered research programs on metals for ships. He was associated intimately with the development of HY-80 steel and prepared the first specification used for its procurement by the Navy. In addition he was responsible for the development of dimpled armor plate for aircraft carrier flight decks. In 1956 he assumed his present position where he has been active in the Ship Structure Committee research program the low cycle fatigue structural program and the hydrofoil materials research program. Mr. Vasta is Head of Hull Scientific and Research Section
Bureau of Ships with the responsibility for planning initiating and technically monitoring research in the fields of structural me
作者：
Fioriti, I.Vasta, J.Starr, A.Mr. Fioriti is the Materials Engineer in the Hull Scientific and Research Section
Bureau of Ships with responsibility for materials and fabrication processes that are used in the construction of ship hulls. Mr. Fioriti attended the University of Pittsburgh receiving the Bachelor of Science degree in Metallurgical Engineering in 1951. He took postgraduate work at the University of Maryland receiving the Master of Science degree in 1960. From 1951 to 1956 he worked in the Metals and Metallurgy Section of the Bureau of Ships where he planned and administered research programs on metals for ships. He was associated intimately with the development of HY-80 steel and prepared the first specification used for its procurement by the Navy. In addition he was responsible for the development of dimpled armor plate for aircraft carrier flight decks. In 1956 he assumed his present position where he has been active in the Ship Structure Committee research program the low cycle fatigue structural program and the hydrofoil materials research program. Mr. Vasta is the Head of Hull Scientific and Research Section
Bureau of Ships with responsibility for planning initiating and technically monitoring research in the fields of structural mechanics and hydromechanics. Mr. Vasta attended New York University receiving the Bachelor of Science degree in Mechanical Engineering in 1930. He took postgraduate work at the Massachusetts Institute of Technology receiving the Master of Science degree in 1931. From 1931 to 1938 he worked at the United States Experimental Model Basin in the structural mechanics group. After a short duty at the Headquarters of the United States Coast Guard he joined in 1939 the staff of the United States Maritime Commission where he held various positions of responsibility in the Technical Division. He was associated intimately with the design development of the reinforced concrete ship program first as Assistant Chief and then as the Chief of the Section. Thereafter he was appointed Assistant Chief of
Research program of U S Bureau of Ships is in final phase;literature survey and screening phases are completed;on basis of tests, fabrication studies and cost analyses most promising materials are steels 4330M and 17-...
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Research program of U S Bureau of Ships is in final phase;literature survey and screening phases are completed;on basis of tests, fabrication studies and cost analyses most promising materials are steels 4330M and 17-4PH (H1025) with protective coatings, and 2 titanium alloys (8AL-2CB-1TA) and (6AL-4V);most promising coatings are polyurethane rubber and neoprene rubber base coatings;coated HY-100 steel is satisfactory for low performance foils;glass laminates are of particular interest as foil materials and are under study;no "off shelf" material is ideal for high speed foils.
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