Browsing by Author "Ivanova M."

Now showing 1 - 8 of 8
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    An effect of heat insulation parameters on thermal losses of water-cooled roofs for secondary steelmaking electric arc furnaces
    (2016-06-01) Mihailov E.; Popgeorgiev P.; Ivanova M.
    The aim of this work is research in the insulation parameters effect on the thermal losses of watercooled roofs for secondary steelmaking electric arc furnaces. An analytical method has been used for the investigation in heat transfer conditions in the working area. The results of the research can be used to choose optimal cooling parameters and select a suitable kind of insulation for water-cooled surfaces.
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    Ceramic materials for SOFCs: Current status
    (2002-01-01) Kozhukharov V.; Brashkova N.; Ivanova M.; Carda J.; Machkova M.
    It is well known that the main parts of Solid Oxide Fuel Cells (SOFCs) are build from ceramic materials. Namely the ceramic materials and composites, used for SOFCs manufacturing, are objects of the overview in the present work. The analysis carried out covers the last current publications in the field discussed. Special attention and examination in details have been done on patents state-of-the-art. After a background and short classification of the ceramic SOFCs materials the attention is focused on cathode, electrolyte, anode, interconnection and sealing materials. Their requirements, structure, thermal stability, composition control and behavior, processing and performance are the object of overview. A correlation has been made between the phase diagrams oxygen incorporation and transport, and SOFC advantages, generally for materials of lanthanum- base perovskite family. In order to analyze the innovative investigations regarding the patent branch of the SOFCs development and application, an object of review was patents from Japan, USA, Germany and European Union. Some examples of the inventions with accent on the ceramic materials are shown. In addition the tendency regarding R&D activities of SOFCs development materials from the leading companies in the world is analyzed. On the base of the most important technological and economical parameters of cell cathode/electrolyte/anode materials an attempt for evaluation and correlation has been made and innovative conceptions are shown.
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    Ceramic materials for SOFCs: Current status
    (2002-01-01) Kozhukharov V.; Brashkova N.; Ivanova M.; Carda J.; Machkova M.
    It is well known that the main parts of Solid Oxide Fuel Cells (SOFCs) are build from ceramic materials. Namely the ceramic materials and composites, used for SOFCs manufacturing, are objects of the overview in the present work. The analysis carried out covers the last current publications in the field discussed. Special attention and examination in details have been done on patents state-of-the-art. After a background and short classification of the ceramic SOFCs materials the attention is focused on cathode, electrolyte, anode, interconnection and sealing materials. Their requirements, structure, thermal stability, composition control and behavior, processing and performance are the object of overview. A correlation has been made between the phase diagrams oxygen incorporation and transport, and SOFC advantages, generally for materials of lanthanum- base perovskite family. In order to analyze the innovative investigations regarding the patent branch of the SOFCs development and application, an object of review was patents from Japan, USA, Germany and European Union. Some examples of the inventions with accent on the ceramic materials are shown. In addition the tendency regarding R&D activities of SOFCs development materials from the leading companies in the world is analyzed. On the base of the most important technological and economical parameters of cell cathode/electrolyte/anode materials an attempt for evaluation and correlation has been made and innovative conceptions are shown.
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    Ceramic materials for SOFCs: Current status
    (2002-01-01) Kozhukharov V.; Brashkova N.; Ivanova M.; Carda J.; Machkova M.
    It is well known that the main parts of Solid Oxide Fuel Cells (SOFCs) are build from ceramic materials. Namely the ceramic materials and composites, used for SOFCs manufacturing, are objects of the overview in the present work. The analysis carried out covers the last current publications in the field discussed. Special attention and examination in details have been done on patents state-of-the-art. After a background and short classification of the ceramic SOFCs materials the attention is focused on cathode, electrolyte, anode, interconnection and sealing materials. Their requirements, structure, thermal stability, composition control and behavior, processing and performance are the object of overview. A correlation has been made between the phase diagrams oxygen incorporation and transport, and SOFC advantages, generally for materials of lanthanum- base perovskite family. In order to analyze the innovative investigations regarding the patent branch of the SOFCs development and application, an object of review was patents from Japan, USA, Germany and European Union. Some examples of the inventions with accent on the ceramic materials are shown. In addition the tendency regarding R&D activities of SOFCs development materials from the leading companies in the world is analyzed. On the base of the most important technological and economical parameters of cell cathode/electrolyte/anode materials an attempt for evaluation and correlation has been made and innovative conceptions are shown.
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    Determination of the coefficient of thermal expansion of epoxy composites
    (2002-01-01) Glavchev I.; Petrova K.; Ivanova M.
    Several compounds were used to design epoxy composites which would exhibit appropriate coefficients of thermal expansion (CTE): bisphenol A and diethyleneglycol based epoxy resins, seven different fillers and two hardeners. The CTE of these epoxy compositions with crystalline and amorphous filler was determined and its peak-like behavior as a function of temperature evaluated. © 2001 Elsevier Science Ltd. All rights reserved.
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    Determination of the coefficient of thermal expansion of epoxy composites
    (2002-01-01) Glavchev I.; Petrova K.; Ivanova M.
    Several compounds were used to design epoxy composites which would exhibit appropriate coefficients of thermal expansion (CTE): bisphenol A and diethyleneglycol based epoxy resins, seven different fillers and two hardeners. The CTE of these epoxy compositions with crystalline and amorphous filler was determined and its peak-like behavior as a function of temperature evaluated. © 2001 Elsevier Science Ltd. All rights reserved.
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    Determination of the coefficient of thermal expansion of epoxy composites
    (2002-01-01) Glavchev I.; Petrova K.; Ivanova M.
    Several compounds were used to design epoxy composites which would exhibit appropriate coefficients of thermal expansion (CTE): bisphenol A and diethyleneglycol based epoxy resins, seven different fillers and two hardeners. The CTE of these epoxy compositions with crystalline and amorphous filler was determined and its peak-like behavior as a function of temperature evaluated. © 2001 Elsevier Science Ltd. All rights reserved.
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    Possibilities for saving energy in ferrous metallurgy: Integration of technological processes
    (2016-01-01) Mihailov E.; Petkov V.; Ivanova M.; Stoyanova B.
    One of the main factors having a significant effect on fuel and energy saving in the production of rolled ferrous metals is matching the operation of the continuous casting machines with that of the re-heating furnaces so called continuous technologies in the form of direct rolling or hot charging. In order to investigate the heat exchange processes, the opportunities for enhancing the energy efficiency and determining the optimal parameters of the flat product production process in ferrous metallurgy, some mathematical models of metal solidification and cooling in a continuous steel casting machine were determined as well as a mathematical model of metal heating in the re-heating furnaces. For efficient implementation of such technologies one common algorithm was built on the basis of the individual mathematical models, representing the continuous casting - rolling mill complex control technology, dynamically matching the operation of the individual units to the actual production conditions in on-line mode. The developed algorithm can be used as part of a system for analyzing the thermal condition of the blocks at any single moment for the purpose of optimization of the units' operation within the whole technological process. As a conclusion, considering the original developed algorithm, a 21-51% energy saving was noticed.