Dissertations / Theses on the topic 'Iron oxides Thermal properties'
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Walker, Jeremy D. "Exploring the Synthesis and Characterization of Nanoenergetic Materials from Sol-Gel Chemistry." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14573.
Full textAyub, Ibrar. "Oxidation and reduction properties of iron-containing oxides." Thesis, n.p, 2001. http://ethos.bl.uk/.
Full textChurch, Nathan Stewart. "Magnetic properties of iron-titanium oxides and their nanoscale intergrowths." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609524.
Full textCussen, Edmund John. "The electronic properties of mixed metal oxides." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301436.
Full textTaylor, Anthony Park 1963. "Terbium iron cobalt diffusion barrier studies." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276931.
Full textGu, Jingjing. "Ternary Oxide Structures for High Temperature Lubrication." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc804963/.
Full textKolincio, Kamil. "Study of thermal and electronic transport properties in low dimensional oxides." Caen, 2013. http://www.theses.fr/2013CAEN2083.
Full textThe thesis was focused on synthesis and study of structural and physical properties of several quasi low-dimensional and anisotropic materials. The physical properties of KxP4W8O32 were examined in purpose to elucidate the phase transition observed for x varying from 0,9 to 1,8. The x content was determined by EDS spectrography under electron microscope. Physical properties like resistivity, magnetoresistance, DC magnetisation, thermopower, thermal transport, and U(I) curves for high currents were studied. Structural study was performed with synchrotron Soleil, beam line Crystal. The obtained results prove the existence of CDW in studied material. The NaxP4W20O68 was sydied by Sbubnikow – de Haas oscillations. The high m members of the (PO2)4(WO3)2m bronzes family were synthesized for the first time. Powders of m = 6, 9, 10 and 11,5 respectively were obtained using solid state reaction method. Large single crystals of m = 10 and m = 11,5 were grown by chemical vapor technique. Crystal structure was solved by X – ray single crystal diffraction. Electrical resistivity and magnetoresistance were studied to investigate the effective dimensionality. The crystallographic and transport measurements were performed to investigate anomaly in m = 6 compound around T = 265. K. Bi-Ba-Co-O misfit cobaltite single crystals were grown by molten salt synthesis method. XRD single crystal diffraction and electron diffraction were performed to identify crystallographic parameters. Composition of the samples was determined by EDS. Surface and cross section of the samples was studied by SEM. Transport properties of samples of different quality was studied
Yamamoto, Takafumi. "Synthesis, Structure, and Physical Properties of Novel Iron Oxides Prepared by Topotactic Reactions." 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/165033.
Full textTassel, Cédric. "Low Temperature Synthesis and Properties of Novel Iron Oxides with Square Planar Coordination." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/126810.
Full textTanaka, Katsuhisa. "ESR AND MOSSBAUER STUDIES ON STRUCTURE AND MAGNETIC PROPERTIES OF IRON-CONTAINING AMORPHOUS OXIDES." Kyoto University, 1990. http://hdl.handle.net/2433/74576.
Full textTeggart, Brian Joseph. "Fabrication, characterisation and magneto-optical enhancement of thin film BiGa : Dy iron garnet." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287432.
Full textZhang, Hantao S. M. Massachusetts Institute of Technology. "Computational investigation of the thermal conductivities and phonon properties of strontium cobalt oxides." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/123356.
Full textThesis: S.M., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2019
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 87-91).
The thermal conductivities of electrochemically tuned strontium cobalt oxides (SCO) are significantly different among the perovskite SrCoO3 (P-SCO), the brownmillerite SrCoO2.5 (BM-SCO) and the hydrogenated HSrCoO2.5 (H-SCO)1. The underlying mechanism causing this large difference is still unclear. And phonon properties in SCO have not been investigated thoroughly or have some contradictive predictions. In this work, we have calculated the thermal conductivities in P-SCO and BM-SCO by applying molecular and lattice dynamics, and successfully reconstructed the large difference of the thermal conductivities, consistent with measurements. Furthermore, several phonon properties including heat capacities, group velocities, lifetimes and mean free paths have been calculated, and the key roles of local atomic environment and crystal symmetry in determining the thermal conductivities have been identified. We have also analyzed the impact of interfaces, isotropic strains and defects on thermal conductivities, predicted the neutron scattering intensity in P-SCO, and tested the accuracy and performance of molecular dynamics based on deep learning. Additionally, even though the calculations about the phonon properties in H-SCO are not complete, it still offers some inspirations about its thermal conductivity. The thorough investigations about the phonon properties and the mechanisms determining the thermal conductivities in SCO may benefit future research about tunable thermal conductivities in complex oxides.
by Hantao Zhang.
S.M.
S.M. Massachusetts Institute of Technology, Department of Nuclear Science and Engineering
Shankle, Angela Janine Arnett. "Influence of water on the photocatalytic properties of synthetic nanocrystalline iron oxide films." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1798967601&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Full textSeinberg, Liis. "Low Temperatures Synthesis and Properties of Ferromagnetic -Metal Nanomaterials and Square-Planar Coordinate Iron Oxides." 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/174955.
Full textLim, ChangDuk. "Materials properties of ruthenium and ruthenium oxides thin films for advanced electronic applications." Thesis, University of North Texas, 2006. https://digital.library.unt.edu/ark:/67531/metadc5592/.
Full textDas, Supriyo. "Synthesis and structural, magnetic, thermal, and transport properties of several transition metal oxides and arsenides." [Ames, Iowa : Iowa State University], 2010. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3403075.
Full textChin, Suk Fun. "Superparamagnetic nanoparticles for biomedical applications." University of Western Australia. School of Biomedical, Biomolecular and Chemical Sciences, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0128.
Full textButt, Naeem Sohail. "Electrochromic devices for solar and thermal radiation control." Thesis, Oxford Brookes University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340600.
Full textBriley, Saebo Karen. "Degradation, Metabolism and Relaxation Properties of Iron Oxide Particles for Magnetic Resonance Imaging." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4311.
Full textSnow, Claine Lindsey Morton. "The Heat Capacity and Thermodynamic Properties of the Iron Oxides and Their Relation to the Mineral Core of the Iron Storage Protein Ferritin." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2435.
Full textAndersson, Martin. "Structural, thermal and thermodynamic properties of some Ln-Pd oxides and their behaviour as catalyst precursors." Doctoral thesis, Stockholms universitet, 1999. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-64279.
Full textHärtill 5 uppsatser
Armstrong, Christopher. "Inoculant measurement with thermal analysis." Thesis, KTH, Materialvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279066.
Full textÖver tid så minskar ympnivån i en smälta på grund av fading och detta måste kompenseras med mertillsatser av ymp. Vid gjutning av CGI400 på Scania används en en-stegs metod där man baserar ymptillsatsen i skänken på vad ympnivån var i sista skänken från den tidigare ugnen. Vid längre produktionsstopp kommer inte ympnivån från ugnen innan vara representativ utan mer ymp måste tillsättas. En metod för att bestämma ympnivån av basjärnet i ugnen skulle göra det lättare att styra processen. Denna studie handlar om ympmätning med hjälp av termisk analys i bas smälta för att få en bättre förståelse för hur den fluktuerar mellan ugnar och ändras över tid. Studien handlar också om hur man ska kunna applicera denna mätmetod i produktionen på ett gjuteri. Med hjälp av termo analytiska mätningar skulle grundnivån av ymp i smältan bestämmas och även för att se hur nivån ändrades över tiden. För att bestämma tillsatsen av ymp som borde tillföras undersöktes mättnadspunkten av ymp och hur den kunde tillsättas i skänk. Resultaten från studien visar att grundnivån av ymp är för låg och resultaten visar också att nivån av ymp fluktuerar både upp och ner ökar tid vilket inte var vad man hade förväntat sig och även det finns flera faktorer som kan påverka nivån. Slutsatsen som kan dras är att termisk analys kan användas i produktion för att bestämma ympnivån, men mer mätningar behövs för att bestämmadess noggrannhet.
Hutton, William Antony D. I. "Investigations into the structure, thermal stability and electrical properties of various bismuth-based oxides, including Sillenite materials." Thesis, University of Sheffield, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419264.
Full textShah, Rakesh K. "Enhancements of Mechanical, Thermal Stability, and Tribological Properties by Addition of Functionalized Reduced Graphene Oxide in Epoxy." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc699889/.
Full textKhan, Brandon Sajad. "The Effects of Gamma (γ-) Sterilization on the Redox Stability, Minerology, and Physicochemical Properties of the Synthetic Iron Oxides Ferrihydrite, Lepidocrocite, and Goethite." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36519.
Full textMorber, Jenny Ruth. "1D nanowires understanding growth and properties as steps toward biomedical and electrical application /." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24825.
Full textCommittee Chair: Snyder, Robert; Committee Co-Chair: Wang, Zhong Lin; Committee Member: El-Sayed, Mostafa; Committee Member: Milam, Valeria; Committee Member: Summers, Christopher; Committee Member: Wong, C. P.
SILVA, MAVIAEL J. da. "Desenvolvimento de selantes vitrocerâmicos para uso em SOFC pertencentes ao sistema BAS (BaO-Alsub(2)0sub(3)-SiOsub(2)) modificados com Bsub(2)Osub(3)." reponame:Repositório Institucional do IPEN, 2014. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23655.
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Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
FLORIO, DANIEL Z. de. "Analise de eletrolitos de ZrO sub(2):Y sub(2) O sub(3) + B sub(2) O sub(3) e de eletrodos de La sub(0,8) Sr sub(0,2) Co sub (0,8) Fe sub (0,2) O sub (3-delta) por espectroscopia de impedancia." reponame:Repositório Institucional do IPEN, 2003. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11130.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
Larsson, Karl. "Influence of nitrocarburization on the thermomechanical fatigue properties of ductile iron for exhaust components : Analysis and comparisons of TMF-properties." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-72033.
Full textLukawska, Anna Beata. "THERMAL PROPERTIES OF MAGNETIC NANOPARTICLES IN EXTERNAL AC MAGNETIC FIELD." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401441820.
Full textWang, Yu. "Mechanical properties and microstructure of laser sintered and starch consolidated iron-based powders." Doctoral thesis, Karlstad : Faculty of Technology and Science, Materials Engineering, Karlstads universitet, 2008. http://www.diva-portal.org/kau/abstract.xsql?dbid=1593.
Full textNiu, Jianbing. "Growth Mechanisms, and Mechanical and Thermal Properties of Junctions in 3D Carbon Nanotube-Graphene Nano-Architectures." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc700065/.
Full textMaraveas, Chrysanthos. "Fire resistance of metal framed historical structures." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/fire-resistance-of-metal-framed-historical-structures(390efc49-7228-4ad1-a164-356213df96fb).html.
Full textGoldblatt, Nicholas Zalmon. "The characterisation of manganese (IV) compounds and the study of the thermal decomposition of potassium chlorate alone and with Mn(IV) and other oxides and salts." Thesis, Brunel University, 1998. http://bura.brunel.ac.uk/handle/2438/5260.
Full textBeckius, Fredrik, and Robin Gustafsson. "Connecting casting simulation and FE software including local variation of physical properties. : Investigation on local material properties and microstructure in a grey iron cylinder head." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Material och tillverkning, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-31248.
Full textLatham, Tina Joy. "Structure and properties of MTiOXOâ†4 crystals." Thesis, University of Warwick, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364604.
Full textRIBEIRO, THATIANA G. D. "Sintese e caracterizacao de nanoparticulas magneticas de oxidos mistos de MnFesub(2)Osub(4) recobertas comm quitosona. Estudos da influencia na dopagem com Gdsup(3+) nas propriedades estruturais e magneticas." reponame:Repositório Institucional do IPEN, 2008. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11515.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Krings, Andreas. "Iron Losses in Electrical Machines - Influence of Material Properties, Manufacturing Processes, and Inverter Operation." Doctoral thesis, KTH, Elektrisk energiomvandling, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145243.
Full textQC 20140516
Silva, Jorge Ayrton da. "Analise termica na solidificação de ferros fundidos cinzentos hipoeuteticos." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264734.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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A análise térmica é amplamente utilizada como método de controle de processos metalúrgicos e na investigação da composição química de ferros fundidos na prática de fundição. Um meio confiável de avaliação da composição de ferros fundidos é disponibilizado pela técnica do Carbono Equivalente, que é baseada na mudança de inclinação da curva de resfriamento na temperatura liquidus durante o resfriamento de uma amostra de ferro fundido a partir do estado líquido. O presente trabalho é focado no desenvolvimento de um novo sensor para análise térmica, um sensor de imersão, que objetiva contribuir com determinações mais confiáveis de composição durante as operações de fundição. Foram desenvolvidos experimentos em diferentes empresas de fundição, utilizando-se tanto o sensor de imersão quanto o tradicional sensor tipo cápsula, normalmente utilizado na prática de fundição. As comparações de composições químicas, medidas por essas duas técnicas e medidas fornecidas por análise de espectrometria de emissão óptica, demonstram que geralmente o sensor de imersão fornece resultados mais confiáveis. Uma análise térmica realizada durante o resfriamento de ferro fundido em um dispositivo unidirecional com uma coquilha, e utilizando um conjunto de termopares, permitiu também a determinação quantitativa de variáveis térmicas de solidificação, tais como: coeficientes transitórios de transferência de calor metal/molde e molde/ambiente e taxa de resfriamento à frente da isoterma liquidus
Abstract: Thermal analysis is a widely used method for metallurgical process control and investigation of alloy composition of cast irons in foundry practice. A reliable means of rapidly evaluating the composition of cast irons is available by the Carbon-Equivalent technique, which is based on the change in thermal arrest temperature of the liquidus as the sample of molten cast iron freezes. The present work focuses on the development of a new sensor for thermal analysis, a dip-sensor, wich aims to contribute to more reliable determination of alloy composition during casting operation. Experiments were carried-out in different foundries by using both the dipsensor and the traditional capsule-sensor, which is normally used in foundry practice. The comparison of alloy compositions measured by these two techniques with analysis performed by Arc/Spark spectrometry has shown that generally the dip-sensor provides more reliable results. Thermal analysis conducted during cooling of molten cast iron in a unidirectional chill apparatus, by using a set of thermocouples, has also permitted the quantitative determination of solidification thermal variables, such as: transient metal/mold and mold/ambient heat transfer coefficients and tip cooling rates
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
SILVA, PAULO S. M. da. "Projeto, construção e testes de um sistema de medidas elétricas e estudo de compósitos de zircônia-ítria e nitreto de titânio." reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/25318.
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Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Prilliman, Gerald Stephen. "Synchrotron X-ray diffraction studies of phase transitions and mechanical properties of nanocrystalline materials at high pressure." Berkeley, Calif. : Oak Ridge, Tenn. : Lawrence Berkeley National Laboratory ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2003. http://www.osti.gov/servlets/purl/825137-DcNEaM/native/.
Full textPublished through the Information Bridge: DOE Scientific and Technical Information. "LBNL--55022" Prilliman, Gerald Stephen. USDOE Director. Office of Science. Office of Basic Energy Sciences (US) 09/01/2003. Report is also available in paper and microfiche from NTIS.
RAMBO, CARLOS R. "Sintese e caracterizacao de ceramicas biomorficas." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10973.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
CARMO, JOÃO R. do. "Síntese, caracterização microestrutural e elétrica de compostos cerâmicos à base de soluções sólidas de titanato de estrôncio, titanato de cálcio e óxido de ferro." reponame:Repositório Institucional do IPEN, 2011. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10035.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Torres, Filho Rodrigo José de Almeida. "Análise térmica de estruturas de aço utilizadas no sistema light steel framing." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2641.
Full textThe thermal performance of light steel framing (LSF) panels was the objective of this study. The study subject was panels used in the construction of two model houses located at Federal Technology University – Parana, built with materials commercially available in Brazil. The analysis was set with material properties from the manufacturer and in compliance with the Brazilian regulation, using the finite element method for a transient thermal analysis. The model validation was based on experimental tests available in the literature. Based on the validated model, the four panels have been analyzed. Two of the panels used PET wool in the cavity for insulation and the analysis was repeated with them replacing it for glass wool. A panel with no insulation was also analyzed to be used as reference. Based on the analysis results and the resistance reduction coefficients proposed by ABNT NBR 14323:2001, the resistance decrease of the studs due to the fire exposure and the panels resistance to fire were determined. Based on the obtained results, it can be affirmed that, depending on the applied load and the required Equivalent time of fire exposure, even the less protective configuration of the panels presented can be viable. The current study presented relevant information about the performance of LSF manufactured in Brazil when exposed to fire.
Ulm, Daniel. "Optimalizace způsobu očkování litiny s kuličkovým grafitem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-382194.
Full textSILVA, MELISSA R. M. da. "Influência de elementos de liga na microestrutura e propriedades magnéticas de ímãs à base de PrFeCoB." reponame:Repositório Institucional do IPEN, 2017. http://repositorio.ipen.br:8080/xmlui/handle/123456789/28019.
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Os ímãs permanentes de terras-raras tem um papel relevante na indústria de dispositivos eletromagnéticos, principalmente no que se refere à produção de motores para veículos híbridos e elétricos e geradores para turbinas eólicas. Com a recente restrição chinesa a exportação de terras-raras, os altos preços e a necessidade de substituição do Dy nesses ímãs, há um interesse mundial por alternativas a essas questões. A adição de elementos de liga em ímãs permanentes de terras raras tem como objetivo a melhora das propriedades magnéticas. O presente trabalho avalia a influência do Ti, V, Cr, Ni, Zr, Nb e Mo na microestrutura e nas propriedades magnéticas de ímãs sinterizados. Os ímãs foram preparados via metalurgia do pó, a partir de pós obtidos pelo processo de decrepitação por hidrogênio (HD). Na produção do ímã Pr16Fe66,9Co10,7B5,7Cu0,7, sem adição de elementos de liga, foi utilizada a mistura das ligas Pr20Fe73B5Cu2 (33% em peso) e Pr14Fe64Co16B6 (67% em peso). Para avaliar a influência das adições foi utilizada a liga Pr14Fe64Co16B6M0,1, onde M = Ti, V, Cr, Ni, Zr, Nb e Mo (67% em peso). As ligas utilizadas e os ímãs produzidos foram caracterizados por Microscopia Eletrônica de Varredura (MEV) e Difração de Raios-X (DRX), e as propriedades magnéticas foram obtidas por meio de Permeâmetro. O ímã com adição de Cr (iHc = 836 KA.m-1) apresentou coercividade intrínseca 11,8% superior ao ímã sem adição de elemento de liga (iHc = 748 KA.m-1). A maior remanência foi observada para o ímã com adição de Nb (Br = 1,04 T). Os ímãs com as adições de Ti, V e Zr apresentaram os maiores valores de produto de energia (BHmáx = 145, 145 e 144 KJ.m-3, respectivamente). Já o ímã com adição de Mo apresentou o maior fator de quadratura (FQ = 0,73) entre todas as amostras, 28% superior ao ímã sem adição de elementos de liga.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
ARATA, ANELYSE. "Degradação a baixa temperatura da Y-TZP odontológica: análise microestrutural e avaliação das propriedades mecânicas." reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/27129.
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O objetivo deste estudo foi a Y-TZP odontológica submetida ao envelhecimento hidrotérmico acelerado (EH). Especificamente: a) determinar a curva cinética de transformação de fase tetragonal para monoclínica; b) calcular a velocidade de crescimento da frente da camada transformada durante o EH; c) avaliar a relação entre a porcentagem de fase monoclínica e profundidade da transformação de fase com a resistência à flexão biaxial (FB); d) avaliar o efeito da associação do EH e fadiga na resistência à FB. Discos sinterizados (YZ- Vita YZ, LP-Lava Plus) foram submetidos ao EH a 120°C, 130°C e 150°C e analisados por difração de raios X (DRX). Uma amostra por grupo foi analisada por microscopia eletrônica de varredura (MEV) e tomografia de coerência óptica (OCT) para calcular a profundidade de transformação de fase e a velocidade da frente de transformação. Grupos de (YZ, LP e LA-Lava) foram submetidos ao EH (150°C) por (n=10): 0, 5, 25, 70 e 140 horas. Após o EH os grupos de YZ foram novamente divididos (n=10): com e sem ciclagem mecânica, todas as cerâmicas foram submetidas ao teste de flexão biaxial (ISO 6872) e análise de variância 1 fator (ANOVA) (α=0,05) para comparar os resultados. Os resultados de DRX indicam que a Y-TZP apresenta um comportamento sigmoidal de transformação de fase devido à limitação da profundidade de penetração dos raios X (~6,3 μm). As análises de MEV e OCT confirmaram o crescimento linear da frente de envelhecimento em função do tempo para todas as temperaturas. O ANOVA 1-fator demonstrou redução de 10-19% da resistência à FB após 140 horas de envelhecimento (150°C) para todas as cerâmicas, havendo correlação negativa entre profundidade da camada transformada e resistência à FB. Extrapolando os resultados de profundidade para 37°C foi calculado que a frente de transformação de fase levaria 1053 e 2104 anos para atingir a profundidade de 62,67μm e 85,55μm responsáveis pela diminuição da resistência mecânica da YZ e LP, respectivamente. A associação do EH com a ciclagem mecânica não apresentou efeitos deletérios para a YZ. O OCT foi validado como método preciso, fácil e rápido para avaliação da camada transformada e estudos de cinética.
Tese (Doutorado em Tecnologia Nuclear )
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
Mozetic, Halston José. "Design de produto : seleção de materiais e processos com aplicação de campo magnético em núcleos de alto-falantes." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2008. http://hdl.handle.net/10183/15735.
Full textThis work aims to present the results obtained with the use of induced magnetic field during the heat treatment of Nodular Cast Iron for speaker cores. For this study development, the chosen material is the nodular cast iron due to the low trading costs and ease of purchase on the market. Ninety samples of nodular cast iron were constructed, with different iron, silicon and carbon contents. Samples, when subjected to annealing, were also subjected to magnetic induction. The final temperature on the heat treatment was in the range of 900ºC to 920ºC, and the magnetic induction was in the range of 16000 to 20000 Gauss. The challenge of this work was in the fact that compositional changes in the nodular cast iron, allied to inclusions of non-magnetizable materials, modify for worse the performance of speaker cores. To obtain a structure that the magnetic field could permeate, the cast iron alloys were selected to eliminate, at most, the presence of non-magnetizable materials, and only then consider a heat treatment process with magnetic induction to make the material suitable for use in speaker cores. To improve the magnetic properties, an alignment of dipoles of the material, through induced magnetic field during annealing was intended. Annealing with induced magnetic field was carried out, observing the performance of the initial magnetic permeability of the samples, and subsequently measured with field saturation equipment The results were correlated with the obtained data from the use of the SAE 1020 steel, with the same conditions of use and laboratory tests. Metallographic and chemical composition analyses were carried out on the samples, and the correlation of these data with the magnetic properties was estmated. Also machinability of the thermal treated with magnetic induction nodular cast iron samples were analyzed and compared with the SAE 1020 steel. From the scientific point of view, one of the contributions of this work is the influence of induced magnetic field during the heat treatment of the samples, since it was possible to verify a significant gain in the magnetic properties of the speaker cores during the performance tests. Another contribution is the fact that gains correlated with the design of the product enable the use of cast iron as an economically viable and fully adjustable material to the high performance of subwoofers. As a result of this work, the possibility of using annealing with magnetic induction was presented as a way to increase the permeability of a material with high carbon content, in this particular case, the nodular cast iron. This research allows asserting that it is possible to develop speaker magnetic cores of nodular cast iron with high performance and also suggest that this technique can be applied to other applications where it is necessary to increase their magnetic performance.
Tourinho, Francisco. "Ferrofluides a base de ferrite de cobalt et de ferrite de manganese : elaboration, comportement physicochimique et magnetique." Paris 6, 1988. http://www.theses.fr/1988PA066570.
Full textAbramova, Elizaveta. "Výroba a vlastnosti litin typu SiMo." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254424.
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