Tesi sul tema "Baritō"
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Janasi, Suzilene Real [UNESP]. "Ferrita de bário: preparação de fases dopadas com cobalto, titânio e estanho". Universidade Estadual Paulista (UNESP), 1997. http://hdl.handle.net/11449/102592.
Testo completoA substituição parcial de íons Fe3+ por pares de íons (Co2+-Ti4+ ou Co2+-Sn4+) na ferrita de bário hexagonal (BaFe12O19) leva a uma substancial diminuição no campo coercitivo (Hc) com uma pequena mudança na magnetização de saturação (Ms), permitindo seu uso em gravação magnética e magneto-óptica de alta densidade. Os diferentes métodos de preparação de ferritas de bário resultam em produtos com propriedades distintas. Neste trabalho, preparou-se BaFe12-2xCoxTixO19 e BaFe12-2xCoxSnxO19 (0,25 £ x £ 1) por coprecipitação, utilizando cloretos dos metais precursores e solução de KOH/K2CO3 como precipitante. Após a secagem, o produto obtido foi calcinado a 950oC por 3h, lavado e seco. Os difratogramas de raios X indicaram a formação da ferrita de bário. As micrografias eletrônicas de varredura mostraram que os pós obtidos apresentam-se na forma de plaquetas hexagonais de 1 a 2mm. As curvas de magnetização das ferritas de bário dopadas mostraram que o campo coercitivo e a remanência diminuem em função do aumento da razão de substituição x. A curva de magnetização da amostra dopada com Co-Ti, com x = 1 é característica de uma ferrita mole, com Hc = 13,5 kA.m-1 (0,17 kOe), Ms = 46,1 emu.g-1 e Mr = 11,0 emu.g-1. Para a amostra dopada com Co-Sn a diminuição de Mr não é significante. Estes resultados mostraram que as propriedades magnéticas das ferritas de bário dopadas obtidas por coprecipitação foram melhoradas, em relação aos dados da literatura para ferrita de bário pura ou dopada.
The partial substitution of Fe3+ ions with pairs of ions (Co2+-Ti4+ or Co2+-Sn4+) in hexagonal barium ferrite (BaFe12O19) leads to a substantial reduction on coercivity (Hc) with only a low change in saturation magnetization (Ms), allowing its use in high density magnetic and magneto-optical recording. Different preparative methods result in barium ferrites with distinguished properties. In this work, BaFe12-2xCoxTixO19 and BaFe12-2xCoxSnxO19 (0.25 £ x £ 1) were prepared by the coprecipitation method using chloride salt precursors and KOH/K2CO3 solution. After drying, the powder was calcinated at 950oC by 3 h, washed and dried. The X ray diffraction patterns indicated the barium ferrite phase formation. The scanning electron micrographs showed that the particles are hexagonal platelike with diameter size ranging from 1 to 2 mm. The magnetization curves of substituted barium ferrites showed that the values of Hc and Mr decrease with the increase of the substitution ratio x. The magnetization curve profile for Co-Ti substituted sample with x =1 is characteristic of a soft ferrite with Hc = 13.5kA.m-1 (0.17 kOe), Ms = 46.1 emu.g-1 and Mr = 11.0 emu.g-1. These results indicated that the magnetic properties of substituted barium ferrites obtained by coprecipitation were improved when compared with the literature data for pure and substituted barium ferrite.
Liu, Fanmao. "Photoresponse of ferroelectric BaTiO3 thin films". Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/458535.
Testo completoBaTiO3 is a lead-free ferroelectric oxide material. BaTiO3 thin films have been widely studied for memory applications due to its charge memory effect resulting from its ferroelectric nature. Nowadays, the scientific community has renewed its interest on BaTiO3, because it holds characteristics that is interesting for rapidly developing areas such as photovoltaics, photoelectric sensing and photocatalysis. The main goal of the present thesis is to study the photoelectric effects on BaTiO3 thin films and to give light on the relevant mechanisms that control them. Ferroelectric materials show intrinsic, unavoidable and exclusive internal electric fields: imprint electric field (Eimp) and depolarization electric field (Edep). Thus distinct photoelectric effects can be obtained due to Eimp and Edep. In the present thesis we have studied in detail the role of Eimp and Edep on photoelectric effects of BaTiO3 films. In particular, it is shown that appropriate measurement configuration can be used to disclose and isolate their contribution. As a result, different transient and constant photoresponses can be obtained as wish. By the same token, their contribution to the ferroelectric switching dynamics are also analyzed. The transient photoresponse finds its origin on the screening of surface charge (photoscreening). In order to modulate its magnitude detailed characterization has been performed. It is concluded that the polarization photoscreening is governed by the presence of water adsorbed at the surface, allowing it to be controlled. However, the photoelectric efficiency has been found to be limited by the low generation of carriers by light, that is the reason why the effect of O substituted by N in BaTiO3 lattice, which should result in band-gap narrowing, hence improving the photoelectric efficiency, has been studied. Interestingly, it is found that ammonia treatments are efficient to improve photoelectric responses, without having any clear evidence of N substitution.
ALMEIDA, JUNIOR Airton Tavares De. "Caracterização da barita e do vidro cristal como atenuadores na blindagem das radiações X e Gama". Universidade Federal de Pernambuco, 2005. https://repositorio.ufpe.br/handle/123456789/9904.
Testo completoCom objetivo de determinar as características de atenuação do minério sulfato de bário (BaSO4) e do vidro cristal utilizados como blindagem contra as radiações ionizantes X e gama, em instalações radiográficas, foi realizado um estudo de atenuação com argamassa e concreto de barita, usados, respectivamente, no revestimento de paredes e em blocos; e com o vidro cristal usado em biombos e janelas. Para isso, foram analisadas 10 placas de argamassa de barita, 3 placas de concreto de barita, com área média útil de 900 cm2 e espessura média de 1 a 5 cm, e 3 placas de vidro cristal, com área útil de 323 cm2, com espessuras de 1, 2 e 4 cm. As amostras foram irradiadas com raios-X, com potenciais de 60, 80,110 e 150 quilovolts, e raios gama do 60Co. As respostas de atenuação (mGy/mAmin) e (mGy/h) ambos a 1 metro, em função da espessura, resultaram na obtenção das curvas de atenuação e de transmissão. Além disso, foram determinadas as espessuras equivalentes das camadas semi e deciredutoras, tanto para o vidro cristal, como para a argamassa e o concreto de barita
Gondim, Priscylla Cinthia Alves. "Desenvolvimento de bloco de veda??o com barita na composi??o de partida para blindagem de radia??o X". Universidade Federal do Rio Grande do Norte, 2009. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12744.
Testo completoConselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
This work main objective is to study the use of bricks in barium X-rays rooms in order to contribute to the optimization of shielding rooms diagnosis. The work was based on experimental measurements of X-ray attenuation (40 to 150 kV), using ceramic seal bearing the incorporation of barium sulfat (BaSO4). Different formulations were studied in three different firing temperatures and evaluated for incorporation in the ceramic body. The composition of 20% of barite processed at a temperature of 950 ? C showed better physical and mechanical properties, is considered the most suitable for the purpose of this work. Were produced bricks sealing composition formulated based on that presented the best technological features. These blocks were tested physically as a building material and wall protective barrier. Properties such as visual, deviation from the square, face flatness, water absorption and compressive strength were evaluated for all the blocks produced. The behavior of this material as attenuator for X-rays was investigated by experimental results which take into account mortar manufacturers barium through the different strains and compared with the reference material (Pb). The simulation results indicated that the ceramic block barium shows excellent properties of attenuation equivalence lead taking into account the energy used in diagnostic X-ray
Este trabalho tem por finalidade principal estudar a utiliza??o de blocos cer?micos baritados em salas de radia??o X, visando contribuir para a otimiza??o da blindagem de salas de diagn?stico. O trabalho foi baseado em medidas experimentais de atenua??o da radia??o X (40 a 150 kV), empregando material cer?mico de veda??o contendo a incorpora??o de sulfato de b?rio (BaSO4). Diferentes formula??es foram estudadas em tr?s temperaturas de queima diferentes e avaliadas as incorpora??es na massa cer?mica. A composi??o de 20% de barita processada a temperatura de 950?C, apresentou melhores propriedades f?sicas e mec?nicas, sendo considerada a mais adequada para a proposta deste trabalho. Foram produzidos blocos cer?micos de veda??o baseados na composi??o formulada que apresentou melhores caracter?sticas tecnol?gicas. Estes blocos foram testados fisicamente como material construtivo de parede e barreira protetora. Propriedades como caracter?sticas visuais, desvio com rela??o ao esquadro, planeza das faces, absor??o de ?gua e resist?ncia ? compress?o foram avaliadas para todos os blocos produzidos. O comportamento deste material como atenuador para a radia??o X foi investigado por meio de resultados experimentais que levaram em considera??o fabricantes de argamassas baritadas atrav?s das diferentes tens?es e comparado com o material de refer?ncia (Pb). Os resultados obtidos nas simula??es indicaram que o bloco cer?mico baritado demonstra ?timas propriedades de atenua??o em equival?ncia ao chumbo levando-se em conta as energias usadas em raios X diagn?stico
Zhong, Zhimin. "Combustion syntheses and characterization of Barium Titanate, Barium Tetratitanate and Lead substituted Barium Tetratitanate /". The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487861396027028.
Testo completoKudelová, Barbora. "Prekonavani barier". Master's thesis, Vysoké učení technické v Brně. Fakulta architektury, 2017. http://www.nusl.cz/ntk/nusl-316300.
Testo completoAlmeida, Jademir Jesus Pirapora de. "Ação da radiação de alta energia nas propriedades mecânicas de compostos elastoméricos a base de SBR carregados com barita". Universidade Presbiteriana Mackenzie, 2012. http://tede.mackenzie.br/jspui/handle/tede/1329.
Testo completoUniversidade Presbiteriana Mackenzie
In this work were studied the action of ionizing radiation on the physical-mechanical properties in elastomeric compounds based on styrene-butadiene rubber (SBR) filled with barite, opening way for application of these composites in the protection and shield against high-energy radiation, in the form of aprons. These aprons come to substitute the elastomeric ones with lead filler in ergonomic and economically advantageous conditions. The effect of high-energy radiation was studied on SBR compounds filled with barite at 50, 75, 100, 125, and 150phr (phr = parts per hundred rubber) of barite concentrations, exposed to ionizing radiation at 0, 100, 200, 500 and 1000kGy doses. The samples were characterized by physic-mechanical tests as rheometry, tensile strength, resilience, hardness, wear resistance, oil absorption, permanent deformation under compression (compression set) and dynamic mechanical thermal analysis. The morphological characteristics were determined by scanning electron microscopy. The results showed that the radiation causes an increase in tensile strength and elongation, the tear strength and hardness, and a decrease in fluid absorção and deformation under compression.
Neste trabalho foi estudada a ação da radiação ionizante nas propriedades físico-mecânicas nos compostos elastoméricos a base de estireno-butadieno (SBR) carregados com barita, abrindo caminho para aplicação destes compostos na proteção e blindagem contra a radiação alta energia, na forma de aventais, vindo substituir os aventais a base de elastômero carregado com chumbo em condições ergonômicas e economicamente vantajosas. Foi estudado o efeito da radiação ionizante em compostos a base de SBR carregado com barita nas concentrações de 50, 75, 100, 125, e 150phr (phr = partes por cem de borracha) de barita expostos à radiação ionizante nas doses de 0, 100, 200, 500 e 1000kGy. As amostras foram caracterizadas por meio de ensaios físico-mecânicos de reometria, de resistência à tração, resiliência, dureza, resistência ao rasgo, absorção de óleo, deformação permanente sob compressão (compression set) e ensaios de análise térmica dinâmico-mecânica. As características morfológicas dos compositos foram determinadas por meio de microscopia eletrônica de varredura. Os resultados mostraram que a radiação provoca um aumento da resistência à tração, do alongamento sob tração, da resistência ao rasgamento e da dureza; e um decréscimo na absorção de fluido e na deformação sob compressão.
FRIMAIO, AUDREW. "Desenvolvimento de um material cerâmico para utilização em proteção radiológica diagnóstica". reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11414.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
Rai, Maha. "Molecular dynamics modelling of barium silicate and barium fluorozirconate glasses". Thesis, University of Kent, 2018. https://kar.kent.ac.uk/66702/.
Testo completoKinsey-Nielsen, Susan Mary. "HIGH-RESOLUTION LASER SPECTROSCOPY OF BARIUM-MONOHYDROXIDE AND BARIUM-MONODEUTEROXIDE". Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/292080.
Testo completoKirby, Nigel Matthew. "Barium zirconate ceramics for melt processing of barium cuprate superconductors". Thesis, Curtin University, 2003. http://hdl.handle.net/20.500.11937/1364.
Testo completoKirby, Nigel Matthew. "Barium zirconate ceramics for melt processing of barium cuprate superconductors". Curtin University of Technology, Department of Applied Physics, 2003. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=16216.
Testo completoBased primarily on solid-state processing research, the optimal stoichiometry for corrosion resistant crucibles was observed over the narrow range of 1.003±0.003 Ba : (Zr + Ht) mole ratio. Residual ZrO2 must be strictly avoided even at very low levels because severe localized expansion of Z a grains during reaction with the melt severely reduces corrosion resistance. Although the effect of Ba-rich phases are less severe, their abundance must be suppressed as much as allowed by the production process. Solid-state derived crucibles with a large barium excess were unstable and readily attacked by water. TEM analysis clearly showed residual Zr02 was present as discrete grains and not as grain boundary films, and also the prevalence of intragranular defects in Ba-rich ceramics. Quantitative knowledge of the narrow range of required stoichiometry is critical for developing successful solid-state and solution chemical processes. Reliably achieving the required stoichiometry and phase purity is experimentally challenging and beyond the capability of many processing systems. Systematic investigation revealed sharp changes in physical properties of processed powders across the phase boundary. The resistance of BaZrO3, of the desired stoichiometry to grain growth during powder processing has not previously been reported in the available literature. At the desired stoichiometry for corrosion resistance, powder grain growth resistance combined with very precise control over stoichiometry makes the solid-state process more competitive with solution-based processes than previously acknowledged in the literature. The development of solution processes for BaZr03 precursors is complicated by aqueous chemistry of zirconium compounds.
This project developed the first chemically derived precursor process demonstrated to produce a ceramic of adequate quality for sustained barium cuprate melt containment. The barium acetate / zirconium oxychloride / ammonium oxalate system provided control over stoichiometry without requiring elevated solution temperatures, a large excess of barium reagents, or reagents containing alkalis. Despite showing the capability to supersede the solid-state process, the oxalate process still requires further refinement to more reliably achieve high sintered densities. Although the attributes required for sustained barium cuprate melt containment are now clear, its routine mass production remains reliant on further development of solution chemical techniques or improvements to the kinetics of solid-state processing. This project advanced ceramic design and processing technology in the BaZrO3 system and provided new approaches in meeting the challenging analytical needs of research and process control for high quality production of this compound.
Cure, Barbie. "Baring It All". ScholarWorks@UNO, 2014. http://scholarworks.uno.edu/td/1909.
Testo completoLehnen, Peer. "Relaxoreigenschaften von Strontium-Barium-Niobat - Relaxor Properties of Strontium-Barium-Niobate". Gerhard-Mercator-Universitaet Duisburg, 2001. http://www.ub.uni-duisburg.de/ETD-db/theses/available/duett-12132001-102821/.
Testo completoWarren, Davis Morgan. "Molecular dynamics simulation of barite and celestite ion-pairs". Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41177.
Testo completoRoach, Dan. "Barite bodies west of Hemlo, Ontario petrofabric and geochemical study". Thesis, University of Ottawa (Canada), 1987. http://hdl.handle.net/10393/5312.
Testo completoMaie, Hiroki. "Synthesis and dielectric properties of nanocrystalline barium titanate and silver/barium titanate particles". Connect to this title online, 2008. http://etd.lib.clemson.edu/documents/1211387100/.
Testo completoNabasenja, Caroline. "Radiation doses for barium meals and barium enemas in the Western Cape South Africa". Thesis, Cape Peninsula University of Technology, 2009. http://hdl.handle.net/20.500.11838/1560.
Testo completoSince their discovery in 1895, the use of x-rays is continuously evolving in medicine making the diagnosis of injuries and diseases more practicable. It is therefore not surprising that x-rays contribute 90% of the radiation dose to the population from manmade sources (DWP, 1992). Moreover, these radiation doses are associated with both fatal and non-fatal cancer risk that is detrimental to adults between 20 to 60 years (Wall, 1996). Radiation dose to individuals therefore needs to be actively monitored in order to minimise such risk. Barium contrast examinations were characterised as one of the radiological examinations that contributed enormously to the collective dose to the patients in the radiology department (DWP, 1992). Determining the diagnostic reference levels of such examinations would reduce the over-exposure of individuals to ionising radiation. Currently in South Africa (SA), there are no diagnostic dose reference levels for barium meal (BaM) and barium enema (BaE) examinations. This study therefore investigated the radiation doses delivered to patients referred for BaM and BaE, obtained potential regional reference doses for these examinations, compared the radiation doses obtained with those from similar dosimetry studies and investigated sources of dose variation among the study sites. A total of 25 BaM and 30 BaE patients in the age range 18 to 85 years, weighing 50 kg to 90 kg, at 3 hospitals in the Western Cape, SA were investigated. The radiation dose to the patients was measured using Dose Area Product (DAP) meters that were permanently fitted onto fixed fluoroscopy units at these 3 hospitals. The third quartile DAP values were 20.1 Gycm2 and 36.5 Gycm2 for BaM and BaE respectively. The median DAP values were 13.6 Gycm2 and 27.8 Gycm2 for BaM and BaE respectively. The median values were recommended as the potential Diagnostic Reference Levels for BaM and BaE as they are less affected by outlying values of under or over- weight (Yakoumakis, Tsalafoutas, Sandilos, Koulentianos et al, 1999). The weights of the patients, fluoroscopy time, the number of images obtained, the use of digital or conventional fluoroscopy equipment and the level of training of the radiologists were the factors considered for dose variation among the 3 hospitals.
Amaral, Graziella Ferecini Bueno. "Utilização de compostos elastoméricos à base de SBR carregados com barita em aventais isolantes de raios X". Universidade Presbiteriana Mackenzie, 2011. http://tede.mackenzie.br/jspui/handle/tede/2741.
Testo completoFundo Mackenzie de Pesquisa
In this study it was studied the physical-mechanical properties of elastomers based on styrenebutadiene rubber (SBR) with the addition of barite, for application of these compounds in protecting in the shielding against radiation X, for the substitution of aprons form based on elastomer fillered with lead in ergonomic and economically advantageous conditions. Elastomeric compounds were studied with different barite concentrations [50, 75, 100, 125 and 150 phr (parts for hundred of rubber)]. The studied properties were: tensile strength, tensile modulus, tear strength, permanent deformation in compression, hardness, absorption of fluid, resilience, measure of rheology, morphological analysis and characterization of attenuating materials to radiation X. Results showed that all compositions exhibit good dispersion of the filler in the matrix. It was observed that with the increase barite concentration there is an increase in hardness beyond not causing significant alteration in the tensile strenght, in the elasticity, as well as in the resistance to the tearing of the material.
Neste trabalho foram estudadas as propriedades físico-mecânicas de elastômeros a base de borracha de estireno-butadieno (SBR) com a adição de barita, para aplicação destes compostos na proteção de blindagem contra a radiação X, para a substituição de aventais a base de elastômeros carregados com chumbo em condições ergonômicas e economicamente vantajosas. Foram estudados compostos elastoméricos com diferentes concentrações de barita [50, 75, 100, 125 e 150 phr (partes por cem de borracha)]. Entre as propriedades estudadas destacam-se: resistência à tração, módulo sob tração, resistência ao rasgo, deformação permanente à compressão, dureza, absorção de fluido, resiliência, medida de reologia, análise morfológica e caracterização de materiais atenuadores à radiação X. Os resultados mostraram que todas as composições apresentam uma boa dispersão da carga na matriz. Observou-se que com o aumento da concentração de barita há um aumento na dureza além de não causar alteração significativa na resistência à tração, na elasticidade, bem como na resistência ao rasgamento do material.
BOTERO, ANA ELISA CASAS. "BIOFLOTATION OF MAGNESITE, CALCITE AND BARITE USING RHODOCOCCUS OPACUS AS BIOREAGENT". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2007. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=10515@1.
Testo completoA bactéria Rhodococcus opacus foi avaliada como biorreagente para a flotação dos minerais da magnesita calcita e barita. As análises para determinar a conformação de parede o R. opacus estabelecem que é constituída por macromoléculas com características anfipáticas. O balanço entre grupos catiônicos e aniônicos da parede atribui um ponto isoelétrico equivalente de 3,2. Os resultados dos testes de aderência indicam que a bactéria R. opacus tem uma forte afinidade por superfícies de características ácido - base. Medidas dos minerais antes e após da interação com o R. opacus revelaram que embora fossem observadas modificações sobre todas as superfícies dos minerais, a bactéria R. opacus apresentou uma melhor afinidade pela superfície da magnesita. A capacidade de adsorção das células sobre as superfícies foi fortemente dependente dos valores de pH e a velocidade de adsorção atingiu a máxima concentração de células nos primeiros 5 minutos. As isotermas para a adsorção da bactéria sobre os minerais poderiam ser categorizadas do tipo Lagmuir (L) , II. A melhor flotabilidade foi observada em pH 7. Para a magnesita, a porcentagem foi de 92% usando uma concentração de R. opacus de 100 ppm. Para calcita os melhores resultados apresentaram flotabilidade de 55% para uma concentração de 250 ppm. Em relação à barita, os melhores valores de flotabilidade (60%) foram obtidos para uma concentração de R. opacus de 350 ppm. A aproximação termodinâmica determinou que a energia de adesão era negativa para todos os sistemas, sugerindo assim uma adsorção espontânea da bactéria sobre as superfícies minerais. Para magnesita e calcita as teorias DLVO confirmam os resultados experimentais, as atrações eletrostáticas entre as partículas determinaram as forças de interação. Já para barita, a teoria de XDLVO poderia predizer o comportamento das células sobre o mineral. Neste caso as interações ácido-base seriam as responsáveis pela adesão.
Rhodococcus opacus micro-organism was evaluated as a biocollector for flotation of calcite and magnesite and barite. Analyses of R. opacus cell wall indicated the macromolecules configurationl. The IEP value of R. opacus was around 3.2,. The acidic IEP value of R. opacus could be due to the presence of anionic groups on the wall that dominate over the cationic groups. The adherence test showed the R. opacus affinity for acid-base surfaces.The behavior of the minerals, before and after R. opacus interaction, was evaluated and showed that the cells adhesion shifted both the minerals zeta potential curves and the reversal charges in comparison to their original isoelectric points. Adhesion tests suggested a higher affinity of the bacteria for magnesite than calcite and barite. The experiments of the adsorption rate of the R. opacus on the minerals surfaces showed fast behavior, achieving a maximum of cell adsorption after 5 minutes. Adsorption isotherm curves for the minerals could be categorized as Lagmuir (L) type II. The best bioflotability results for the minerals were achieved for pH 7. Magnesite reached values around 93% for a R. opacus concentration of 100 ppm. For calcite the best flotability was of 55% for a R. opacus concentration of 220 ppm. For barite, the best flotability achieved 70% for a bacterial concentration of 350 ppm. Using the thermodynamic approach of the minerals systems, the adhesion energy of R. opacus on the surfaces was negative. The result suggested a spontaneous adsorption of R. opacus on to the all minerals. For magnesite and calcite, the DLVO theory can predict the cell behavior on the minerals surfaces. The electrostatic attractions determine the interaction forces. For barite and pH 7, the X- DLVO theory predicted the R. opacus adhesion on the surface by acid base interactions.
Hosler, Carrie E. "Fluid flow, heat, and mass transfer of barite mineralization in Missouri /". free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1421142.
Testo completoJakubek, Zygmunt J. (Zygmunt Jerzy). "Rydberg spectroscopy of barium monofluoride". Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/32154.
Testo completoBarath, Aljosha [Verfasser]. "Kommerzialisierung der Sportlerpersönlichkeit / Aljosha Barath". Baden-Baden : Nomos Verlagsgesellschaft mbH & Co. KG, 2018. http://d-nb.info/1160309469/34.
Testo completoYang, Yaodong. "Barium Titanate-Based Magnetoelectric Nanocomposites". Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/38666.
Testo completoPh. D.
Boleslavská, Yvona. "Pracovní (výrobní) prostředí bez bariér". Doctoral thesis, Vysoké učení technické v Brně. Fakulta architektury, 2014. http://www.nusl.cz/ntk/nusl-233272.
Testo completoGross, Timothy M. "[Beta]-barium borate thin film formation on silicon through metal organic decomposition of two novel precursors, barium dimesitylborinate and barium (18-crown-6) cyclotriboroxane /". Online version of thesis, 2004. http://hdl.handle.net/1850/11802.
Testo completoSmith, Esther Jane. "The biogeochemical behaviour of trace-metals in seasonally anoxic lake". Thesis, Lancaster University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266804.
Testo completoThomas, Gilberto Lima. "A interação bárion-bárion na aproximação de estado ligado ao modelo de Skyrme". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2000. http://hdl.handle.net/10183/31456.
Testo completoIn this work we study, in the framework of the bound state approach to the SU(3) Skyrme model, the baryonic number—two strange sector. We analyze situations where the two baryons involved are bound to forni the so called dibaryons and where two free baryons are simply scattered. In the first case, with the help of the generalized axially symmetric ansatz, the dibaryon spectrum is calculated and compared with the one obtained in the non relativistic quark model. A prediction about the existente of the H—particle is also made. In the second case we have used the product ansatz to develop a formalism to study the baryon—baryon interaction, calculating the corresponding potential. Detailed expressions and numeric results are presented for the AN interaction, with the central, spin—spin and tensor components of the potential being obtained and compared with other phenomenological results.
Lee, Chung-Kook. "Crystallization of Nano-sized barium ferrite". Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/19920.
Testo completoCannell, David Stuart. "The electric strength of barium titanate". Thesis, University of Leeds, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.237676.
Testo completoQuadros, da Cunha Feteira AntoÌnio Manuel AndreÌ. "Characterisation of barium titanate based ceramics". Thesis, University of Sheffield, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407525.
Testo completoAbdulla, Sarah Ahmed Eltayed. "Barium sulphate : problems, solutions and applications". Thesis, University of Surrey, 2010. http://epubs.surrey.ac.uk/848627/.
Testo completoJohnston, Diane E. "Characterisation of lanthanum-doped barium titanate". Thesis, University of Aberdeen, 1993. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU554634.
Testo completoSmetana, Volodymyr. "Subnitride im System Alkalimetall-Barium-Stickstoff". [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-36312.
Testo completoDe, Palatis Michael V. "Production of cold barium monohalide ions". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50251.
Testo completoSouza, João Geraldo Martins de. "Argamassa baritada : teste da proporção e da espessura do revestimento, para uso como barreira de proteção para raios-x de 30K e V de energia efetiva, em clinicas odontologicas". [s.n.], 1992. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288884.
Testo completoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
Made available in DSpace on 2018-07-14T02:20:12Z (GMT). No. of bitstreams: 1 Souza_JoaoGeraldoMartinsde_M.pdf: 1939298 bytes, checksum: db33f1f8c25e3f28983e120355828c46 (MD5) Previous issue date: 1992
Resumo: O presente estudo teve o propósito de determinar a proporção ideal do mineral barita em argamassa de revestimento. E a espessura necessária e equivalente à espessura de chumbo para barrar ou absorver raios-X de aproximadamente 30keV de energia efetiva, para blindagens em clinicas de radiologia odontológica. Foram confeccionados blocos de argamassa baritada com 150x150mm e espessuras de 1.4 a 15.1mm. Foi utilizado como fonte de radiação um a aparelho GE 100 modelo A0061. Os feixes incidentes e emergentes de radiação, foram medidos por meio de dosimetros termoluminescentes de Fluoreto de Litio 700, e por câmara de ionização e eletrometro Victoreen modelos 600-4 e 600 respectivamente, e ainda foi feito um cálculo teórico a partir dos elementos componentes da argamassa, para uma comparação com os resultados nos testes. Os resultados evidenciaram que a barita, numa proporção de 60%, em relação aos demais componentes da argamassa estudada, para raios-X de aproximadamente 30keV de energia efetiva (93.7 kVp), foi obtido por meio de um fator de conversão de 5.6 da espessura da argamassa para espessura necessária de chumbo. A camada semi-redutora (HVL) da argamassa baritada foi de 1.24mm e a camada semi-redutora (HVL) do chumbo foi de O.22mm. Assim sendo, para cada milímetro de chumbo seria necessário 5.6mm da argamassa de revestimento para uma proteção eficiente
Abstract: The present paper has the aim of determine the ideal portion of baryte mineral in plaster and the necessary equivalent thickness of plumbum to absorb or stop x-rays in nearly 30keV effective energy, in isolating odontological clinics. Baryte plaster boards were made at 150x150mm and from 1.4 to 15.1mm of thick. As a radiation source, a GE 100, model A0061 device was used. The incidental and emergent radiadion beams were measured with Lithium Fluoride 700 dosimeter and ionization chamber and Victoreen electrometer models 600-4 and 600 respectively. A theo cal calculus was also done from the plaster compound elements for a testing result comparison. The results highlighted that baryte in 60% portion related to the other studied plaster compounds for x-rays nearly 30keV effective energy (93.7kVp) was obtained through a convertion factor of 5.6 in the plaster thickness for the plumbum necessary thickness. The baryte plaster half-value-layer (HVL) was 1.24mm and the plumbum half-value-layer was 0.22mm. Hence, for each plumbum milimeter it would be necessary 5.6mm of plaster for an efficient protection
Mestrado
Radiologia
Mestre em Odontologia
Kaur, Mehar. "The Terrestrial Biogeochemical Cycle of barium: A proposed study to examine barium flux in Mojave Desert dust". Scholarship @ Claremont, 2013. http://scholarship.claremont.edu/scripps_theses/150.
Testo completoGurav, Ankita B. "Investigating Heterogeneous Nucleation of Barite using Hydrothermal Atomic Force Microscopy and Optical Microscopy". Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1610403323603442.
Testo completoNiggli, Stefan. "Klassische und laser-spektroskopische Untersuchungen an Barium /". [S.l.] : [s.n.], 1987. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=8416.
Testo completoWu, Wenzhong. "Low Temperature Sintering Semiconductive Barium Strontium Titanate". FIU Digital Commons, 2007. http://digitalcommons.fiu.edu/etd/76.
Testo completoGallagher, Andrew James. "Modelling barium isotopes in metal-poor stars". Thesis, University of Hertfordshire, 2012. http://hdl.handle.net/2299/9224.
Testo completoWegmann, Markus Rolf. "Microextrusion of barium titanate for PTCR applications". Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248863.
Testo completoCui, Yongfei. "Ferroelectric barium titanate for semiconductor photocatalytic application". Thesis, Queen Mary, University of London, 2015. http://qmro.qmul.ac.uk/xmlui/handle/123456789/9530.
Testo completoLea, David Wallace. "Foraminiferal and coralline barium as paleoceanographic tracers". Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/54332.
Testo completoJette, Bruce Donald. "Feasibility of electrodeposition of yttrium and barium". Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/79452.
Testo completoFallon, Joseph John. "Multiscale theory and simulation of barium titanate". Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/28089.
Testo completoJech, David. "Příprava a strukturní stabilita nanokrystalických tepelných bariér". Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-391813.
Testo completoFathi, Ariya Reza. "Barium Solidification/Stabilization of Legacy Fly Ash". University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1523014706886586.
Testo completoFung, Sing Chor. "Conductivity fluctuations in yttrium barium cooper oxides". HKBU Institutional Repository, 1994. http://repository.hkbu.edu.hk/etd_ra/34.
Testo completoAustin, Peter Evans. "Baring Brothers and the panic of 1837 /". Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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