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Duddukuri, Ramesh. "SYNTHESIZING AND CHARACTERIZATION OF TITANIUM DIBORIDE FOR COMPOSITE BIPOLAR PLATES IN PEM FUEL CELL." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/862.
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This research deals with the synthesis and characterization of titanium diboride (TiB2) from novel carbon coated precursors. This work provides information on using different boron sources and their effect on the resulting powders of TiB2.The process has two steps in which the oxide powders were first coated with carbon by cracking of a hydrocarbon gas, propylene (C3H6) and then, mixed with boron carbide and boric acid powders in a stoichiometric ratio. These precursors were treated at temperatures in the range of 1200-1400° C for 2 h in flowing Argon atmosphere to synthesize TiB2.The process utilizes a carbothermic reduction reaction of novel carbon coated precursor that has potential of producing high-quality powders (sub-micrometer and high purity). Single phase TiB2 powders produced, were compared with commercially available titanium diboride using X-ray diffraction and Transmission electron microscopy obtained from boron carbide and boric acid containing carbon coated precursor.
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Mjali, Kadephi Vuyolwethu. "Laser bending of commercially pure grade 2 titanium alloy plates: mechanisms analysis and characterisation of mechanical properties." Thesis, Nelson Mandela Metropolitan University, 2014. http://hdl.handle.net/10948/d1021147.
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The processing of materials has become a specialist field and the industry will continue to grow due to rising costs in labour and raw materials which has forced many automotive industry suppliers to invest heavily in this field. In order to be relevant and competitive in today’s industrial world, companies in South Africa are now forced to dedicate billions of rands in profits to research and development. Metals like titanium are finding favour with automotive and aviation companies in pursuit of savings in fuel consumption. This saving is achieved by reducing weight on aircraft and automobiles yet still meeting acceptable and improved structural integrity. In-depth research into the behaviour of various materials under varying loading conditions is therefore essential. The study on the processing of commercially pure grade 2 titanium alloy plates focuses on the development of process parameters for bending the material using a 4kW Nd: YAG laser to an approximate radius of curvature of 120mm. The resulting mechanical properties of laser formed plates are then compared to those obtained from mechanically formed samples. The titanium parent material was used to benchmark the performance of formed samples. The effect of process parameters on the mechanical properties and structural integrity also formed part of this study. To obtain the bending parameters for laser forming, various combinations of processing speeds and laser powers were used. The line energy is dependent on the power and scanning velocity parameters and these are shown in table 1. The laser power, line energy and scanning velocity were the main parameters controlled in this study and the beam diameter remained unchanged. Residual stress analysis, micro-hardness and fatigue life testing were carried out to analyse mechanical properties and the structural integrity of the plate samples. Microstructural analysis was also done to observe changes in the material as a result of the forming processes. From the results it is evident that laser forming is beneficial to the hardness of titanium but detrimental to the fatigue life at higher line energies. Residual stress analysis showed the amount of stress within the study samples increased with each forming operation. This information was vital in the analysis of the fatigue life of titanium. A fatigue life prediction model was developed from this study and it shed some light on the behaviour of titanium in fatigue testing. The model could be used to predict fatigue life when no fatigue data is available for commercially pure grade 2 titanium alloy plates. In conclusion, this study helped establish parameters that could be used to bend titanium while the analysis of mechanical properties showed the limits of working with this alloy.
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Mjali, Kadephi Vuyolwethu. "Mechanisms, analysis and characterisation of mechanical properties of laser formed commercially pure grade 2 titanium alloy plates." Thesis, Nelson Mandela Metropolitan University, 2014. http://hdl.handle.net/10948/d1021083.
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The processing of materials has become a specialist field and the industry will continue to grow due to rising costs in labour and raw materials which has forced many automotive industry suppliers to invest heavily in this field. In order to be relevant and competitive in today’s industrial world, companies in South Africa are now forced to dedicate billions of rands in profits to research and development. Metals like titanium are finding favour with automotive and aviation companies in pursuit of savings in fuel consumption. This saving is achieved by reducing weight on aircraft and automobiles yet still meeting acceptable and improved structural integrity. In-depth research into the behaviour of various materials under varying loading conditions is therefore essential. The study on the processing of commercially pure grade 2 titanium alloy plates focuses on the development of process parameters for bending the material using a 4kW Nd: YAG laser to an approximate radius of curvature of 120mm. The resulting mechanical properties of laser formed plates are then compared to those obtained from mechanically formed samples. The titanium parent material was used to benchmark the performance of formed samples. The effect of process parameters on the mechanical properties and structural integrity also formed part of this study. To obtain the bending parameters for laser forming, various combinations of processing speeds and laser powers were used. The line energy is dependent on the power and scanning velocity parameters and these are shown in table 1. The laser power, line energy and scanning velocity were the main parameters controlled in this study and the beam diameter remained unchanged. Residual stress analysis, micro-hardness and fatigue life testing were carried out to analyse mechanical properties and the structural integrity of the plate samples. Microstructural analysis was also done to observe changes in the material as a result of the forming processes. From the results it is evident that laser forming is beneficial to the hardness of titanium but detrimental to the fatigue life at higher line energies. Residual stress analysis showed the amount of stress within the study samples increased with each forming operation. This information was vital in the analysis of the fatigue life of titanium. A fatigue life prediction model was developed from this study and it shed some light on the behaviour of titanium in fatigue testing. The model could be used to predict fatigue life when no fatigue data is available for commercially pure grade 2 titanium alloy plates. In conclusion, this study helped establish parameters that could be used to bend titanium while the analysis of mechanical properties showed the limits of working with this alloy.
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Faghihi, Shahabeddin. "Effects of crystal size and orientation of novel titanium-based substrates on cell adhesion : implication for medical implants." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=111882.
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The high performance of bone implants depends on the positive response of osteoblasts to the surface of the materials manufactured for the implant. Cell response in turn strongly depends on the nature of the initial interaction of macromolecules involved in cell adhesion and proliferation with the atomic structure of the surface of the material used for the implant. The initial interaction between bone specific extracellular matrix proteins and the solid substrate influences cell response at the cell-implant interface. This interaction is crucial for implant stability, long-term durability, and osseointegration. Despite extensive research undertaken to develop high-quality material for implants in order to improve the cell-substrate interaction, little is known about the significance of the atomic structure of the substrate and the role of molecular machinery involved in cell-substrate interaction. Using a combined approach involving material sciences and cell and molecular biology, the objectives of this research are to evaluate the response of pre-osteoblast and fibroblast cell lines to novel bulk polycrystalline and single crystal titanium based material and assess the role of crystal size and orientation.Novel bulk nano-structured titanium substrates were produced by the process of high-pressure torsion (HPT). These materials have a significant advantage compared to conventional titanium-based materials by having higher surface wettablity, mechanical properties as well as a distinct surface oxide layer and atomic structure. A co-culture system was adapted to investigate the differential response of pre-osteoblast and fibroblast cell lines to titanium and titanium dioxide single-crystal substrates.
The results of this study provide clear evidence that crystal size and specific crystallographic orientation can be used to improve cell adhesion and proliferation. The nanostructured titanium substrates show strong interaction with pre-osteoblast cells as evident by the higher expression of fibronectin and the formation of extensive focal adhesion. Differential cell behaviour of pre-osteoblasts and fibroblasts are observed in cultures grown on the substrates with specific crystallographic orientations. The degree of cell attachment of the pre-osteoblasts is considerably higher on Ti-(1120) crystal face compared with the fibroblasts. These findings have profound implications for the improved osseointegration and inhibition of fibrosis leading to long-term implant consolidation and stability.
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Trivellato, Alexandre Elias. "Resistencia a flexão de fixação em osteotomia de costela bovina, variando o numero, a localização e a extensão das placas." [s.n.], 2001. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289684.
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Orientador: Luis Augusto PasseriTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O objetivo deste estudo foi avaliar a estabilidade da fixação promovida por placas e parafusos de titânio do sistema de 2,0 mm, realizada em osteotomia de costela bovina submetidas ao teste de resistência à flexão variando o número, a extensão e a localização das placas. Do teste de resistência à flexão, foram obtidos valores de carga aplicada e de deslocamento na área da osteotomia. Os valores foram avaliados por meio do teste de Tukey em nível de significância de 5%. Na carga aplicada foi observado melhor comportamento quando da utilização de duas placas de seis furos ou duas placas sendo uma de seis furos na base e de quatro furos na região superior. Em seguida, de duas placas de quatro furos e, em ordem decrescente, mas sem variação quanto ao tamanho das placas, por uma na porção superior e finalmente por uma na base. Quanto ao deslocamento, não houve variação pela extensão da placa, onde o menor valor foi observado para uma placa na posição superior e o pior com uma placa em borda inferior, não havendo diferença com duas placas relacionadas ao maior ou ao menor deslocamento
Abstract: The aim of this study was to evaluate the stability fixation promoted by titanium plates and screws of 2.0mm system. It was done in vitro by using 2.0mm system in osteotomies carried out in bovine ribs thereafter submitted to bending test changing the number, the extension, and the location of the plates. From bending tests were obtained the load applied and the gap between the superior cortices of bone in the osteotomy area. The values were compared through Tukey test with 5% of significance. Considering the applied load, the best results were seen when either two 6-hole plates or a combination of 6 hole and 4-hole were used, the former in the basis and the later superiorly. Those were followed by the results obtained with using two 4-hole plates. Lower applied loads were obtained, despite of the size, using only one plate superiorly and only one in the basis. Related to gap between the superior cortices of bone there was no influence of the plate extension, and the lower value was obtained with one plate superiorly and the higher was obtained with one plate in the basis
Doutorado
Cirurgia e Traumatologia Buco-Maxilo-Faciais
Doutor em Clínica Odontológica
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Klištinec, Dávid. "Deformační a napěťová analýza lebečních fixátorů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-382556.
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Zranenia hlavy si často vyžadujú lekársku starostlivosť, pri ktorej dochádza k stabilizácii alebo náhrade poškodeného tkaniva. Pre tento účel slúži kranioplastika, ktorá prinavracia pacientovi ochranný a kozmetický výsledok. Výber správneho materiálu kraniálneho implantátu je veľmi podstatný. Naviac potrebuje správny druh fixácie, ktorá ho udrží na mieste a predíde sa tak nedovolenému pohybu implantátu počas bežného života pacienta. Táto práca analyzuje deformačné a napäťové stavy dvoch druhov fixačných plátov prichytených na PMMA implantáte a ich mechanickej odozvy na rozličné záťažné podmienky spôsobené rôznymi stavmi kraniálnej hypertenzie a silou pôsobiacou na sústavu z exteriéru.
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Pinto, Clarice Maia Soares de Alcântara 1986. "Metallographic, gas and energy dispersive x-ray analyses of osteosynthesis plates and screws and dental implants removed from patients with clinical indication = Análise metalográfica, de gases e espectrometria por energia dispersiva de raios-x de placas e parafusos para osteossíntese e de implantes dentários removidos de pacientes com indicação clínica." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/287888.
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Orientador: Márcio de MoraesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O objetivo do presente trabalho foi avaliar a microestrutura e a composição química dos implantes dentários, placas e parafusos para osteossíntese removidos de pacientes em casos com indicação clínica. No trabalho 1, foram realizadas análises metalográfica, de gases e de espectrometria por energia dispersiva de raios-X de placas e parafusos de titânio utilizados para osteossíntese e removidos de 30 pacientes. Os prontuários destes pacientes foram avaliados para obtenção de dados referentes à idade, gênero, procedimento cirúrgico que havia motivado a inserção das placas e parafusos para osteossíntese, a razão clínica para remoção e o tempo de permanência destes dispositivos in situ. Quarenta e oito placas e 238 parafusos foram removidos no total. Infecção consistiu na principal causa para remoção destes dispositivos, correspondendo a 43.3% dos casos. O principal sítio do qual as placas e os parafusos foram removidos foi a mandíbula, equivalendo a 66.6% dos casos. Todas as placas e parafusos analisados estavam dentro das normas F67 e F136 da ASTM (American Society for Testing and Materials) de acordo com a análise metalográfica e a espectrometria por energia dispersiva de raios-X. Na análise de gases, cinco amostras apresentaram valores acima do regulamentado pela ASTM para os elementos Hidrogênio e/ou Oxigênio. A partir do estudo, pôde-se concluir que as propriedades físicas e químicas das amostras não estavam associadas à condição clínica que ocasionou a remoção destes dispositivos e que o tempo de permanência destes implantes in situ não determinou alterações em suas propriedades. No trabalho 2, foram realizadas análises metalográfica e de espectrometria por energia dispersiva de raios-X para avaliação de 38 implantes dentários de titânio removidos de 29 pacientes com indicação clínica. Os prontuários destes pacientes foram avaliados para obtenção de dados referentes à idade, gênero, razão clinica para remoção e tempo de permanência dos implantes. Falta de osseointegração sem sintomatologia ou sinais de infecção associados foi a principal causa para falha dos implantes, correspondendo a 55.1% dos casos. A maxila foi o sítio de falha dos implantes dentários em dezessete pacientes (58.6%) enquanto doze pacientes (41.4%) apresentaram falha de implantes instalados na mandíbula. Todos os implantes analisados eram constituídos de titânio comercialmente puro e apresentaram-se dentro da norma F67 da ASTM. A partir do estudo, pôde-se concluir que as propriedades físicas e químicas dos implantes dentários analisados não estavam associadas ao insucesso no tratamento e à falha destes dispositivos
Abstract: The aim of this study was to evaluate the microstructure and chemical composition of dental implants, bone plates and screws removed from patients in cases of clinical indication. In the first study, metallographic, gas and energy dispersive X-ray analyses were performed to evaluate osteosynthesis plates and screws retrieved from 30 patients. The medical records of these patients were evaluated to obtain data regarding age, gender, surgical procedure that had motivated the insertion of osteosynthesis plates and screws, the reason for removal and the period of time of these devices in situ. Forty-eight plates and 238 screws were removed in total. Infection was the main reason for these devices removal, representing 43.3% of cases. Mandible was the main site for plates and screws removal, corresponding to 66.6% of cases. All plates and screws analyzed were within the specifications F67 and F136 of ASTM (American Society for Testing and Materials) according metallographic and energy dispersive X-ray analyses. In gas analysis, five samples had hydrogen and/or oxygen values above the regulated by ASTM. From the study, it was concluded that the physical and chemical properties of the samples were not associated with the clinical condition that caused the removal of these devices, and retention time of these implants did not determine changes in their properties. In the second study, metallographic and energy dispersive X-ray analyses were performed for evaluation of 38 dental implants removed from 29 patients with clinical indication. Medical records of these patients were evaluated to obtain data regarding age, gender, reason for removal and period of time in situ. Lack of osseointegration without symptomatology or signs of infection was the main reason for dental implants failure, corresponding to 55.1% of cases. Maxilla was the site of implants failure in seventeen patients (58.6%) while twelve patients (41.4%) had failure of dental implants installed in mandible. All dental implants analyzed were manufactured of commercially pure titanium and were within the ASTM F67 specification. From the study, it was concluded that physical and chemical properties of dental implants analyzed were not associated with failure of these devices.
Mestrado
Cirurgia e Traumatologia Buco-Maxilo-Faciais
Mestra em Clínica Odontológica
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Гудименко, Олена Олександрівна, Елена Александровна Гудыменко, Olena Oleksandrivna Hudymenko, Євген Вікторович Кузенко, Евгений Викторович Кузенко, Yevhen Viktorovych Kuzenko, Анатолій Миколайович Романюк, Анатолий Николаевич Романюк, and Anatolii Mykolaiovych Romaniuk. "Розробка титанових пластин для металостеосинтеза нижньої щелепи з урахуванням функції м'язового апарату." Thesis, Сумський державний університет, 2017. http://essuir.sumdu.edu.ua/handle/123456789/64481.
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Остеосинтез широко використовується в щелепно-лицевій хірургії та травматології для усунення деформацій скелета різного генезу, тому до цих пір не припиняються пошуки сучасних матеріалів і пристроїв для фіксації кісткових фрагментів, які були б позбавлені всіх притаманних їм недоліків. Літературний аналіз показав, що під час сучасного дослідження металостеосинтеза за допомогою комп'ютерного моделювання спрощуються вектори м'язової тяги і остеопоротичні зміни в кістковій тканині.
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Yoon, Hyungjin. "Effect of substrate bias and temperature on the structure of ion-plated titanium." Diss., Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/19167.
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Lowe, Michael John Stuart. "Plate waves for the NDT of diffusion bonded titanium." Thesis, Imperial College London, 1992. http://hdl.handle.net/10044/1/8011.
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Hurtuk, Therese M. "Investigating and Understanding the Behavior of a Titanium Alloy Gusset Plate Under Block Shear." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1312858731.
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Palejwala, Sheri K., Jesse Skoch, and G. Michael Lemole. "Removal of symptomatic craniofacial titanium hardware following craniotomy: Case series and review." Elsevier, 2015. http://hdl.handle.net/10150/621246.
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UA Open Access Publishing FundTitanium craniofacial hardware has become commonplace for reconstruction and bone flap fixation following craniotomy. Complications of titanium hardware include palpability, visibility, infection, exposure, pain, and hardware malfunction, which can necessitate hardware removal. We describe three patients who underwent craniofacial reconstruction following craniotomies for trauma with post-operative courses complicated by medically intractable facial pain. All three patients subsequently underwent removal of the symptomatic craniofacial titanium hardware and experienced rapid resolution of their painful parasthesias. Symptomatic plates were found in the region of the frontozygomatic suture or MacCarty keyhole, or in close proximity with the supraorbital nerve. Titanium plates, though relatively safe and low profile, can cause local nerve irritation or neuropathy. Surgeons should be cognizant of the potential complications of titanium craniofacial hardware and locations that are at higher risk for becoming symptomatic necessitating a second surgery for removal.
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Chernchujit, Bancha. "Arthroscopic reconstruction of the coracoclavicular ligaments with suture anchors and small titanium plate a comparative biomechanical study /." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972588663.
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El-Bialy, B. H. M. "A metallurgical and machining study of the behaviour of ion plated titanium nitride coated high speed steel cutting tools." Thesis, University of Salford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372142.
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Silvestri, Siara. "Obtenção de placas fotocatalíticas de TiO2 a partir de estruturas biomórficas." reponame:Repositório Institucional da UFSC, 2015. https://repositorio.ufsc.br/xmlui/handle/123456789/134952.
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Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Química, Florianópolis, 2015.Made available in DSpace on 2015-09-15T04:08:41Z (GMT). No. of bitstreams: 1 334248.pdf: 5987257 bytes, checksum: a364a5f941016972e61bb4753440ea6b (MD5) Previous issue date: 2015
Nesta tese de doutorado foram desenvolvidas e caracterizadas placas finas e planas de dióxido de titânio (TiO2) a partir da infiltração de soluções precursoras de titânio em matriz orgânica (papel), seguido de hidrólise em hidróxido de amônio, como uma alternativa tridimensional para a fixação do TiO2. O grande interesse de obter placas finas deve-se à maior relação superfície/volume, com grande área superficial ativa. A ação fotocatalítica é especialmente favorecida por TiO2 na faixa nanométrica e pela fase anatase majoritária, que é a fase ativada sob radiação ultravioleta (UV-A). Além disso, as placas foram produzidas por infiltração direta, evitando a geração de subprodutos de síntese. A adição de cargas através da incorporação de íons dopantes (Ba2+ e La3+) nas soluções precursoras introduz cargas na rede cristalina, e a incorporação de íons Zr4+ pode causar tração na rede por agir como um íon substitucional de raio atômico levemente maior que o do Ti4+. Foram também avaliados os efeitos das adições dos íons Ba2+, La3+ e Zr4+ na transição de fase anatase para rutilo. Foi avaliado o efeito da matriz orgânica e das diferentes temperaturas de infiltração e calcinação no processo de transição de fase, conteúdo de fase e da incorporação de dopantes através de caracterizações por microscopia eletrônica de varredura, difratometria de raios-X e por área superficial específica. Foram ainda determinados o tamanho dos cristalitos pela equação de Scherrer e as energias do bandgap pela análise dos espectros na região do UV-Vis. Os parâmetros de rede das amostras refinadas pelo Método de Rietveld, foram determinados pelo programa JANA2000. Os radicais gerados nos ensaios de fotoatividade foram caracterizados por espectroscopia de ressonância paramagnética eletrônica. Já os subprodutos da descoloração do corante laranja II foram avaliados por cromatografia líquida. A matriz orgânica fornece a microestrutura para a geração de placas de TiO2, e essa microestrutura aumenta a temperatura de transição de fase anatase para rutilo. A fase anatase esteve majoritária até 800 ºC e presente acima de 1000 ºC. A eficiência fotocatalítica foi eficaz para todos os testes realizados (meio aquoso, gasoso e biológico), e melhor quando comparada ao pó comercial P25 usado como padrão.
Abstract : In this PhD thesis, were developed and characterized flat thin-plates of titanium dioxide (TiO2) infiltration from the titanium precursor solution in the organic matrix (paper), followed by hydrolysis in ammonium hydroxide as a tridimensional alternative to the fixing of TiO2. The great interest to obtain thin plates is due to the higher surface/volume ratio, with large active surface area. The photocatalytic action is especially favored by TiO2 in the nanometer range and the majority anatase phase which is the active layer under ultraviolet radiation (UV-A). Furthermore, the TiO2 plates were produced by direct infiltration, avoiding the generation of synthesis products. Charge addition by the addition of dopants ions (Ba2+ and La3+) in the precursor solutions introduces loads in the crystal lattice, and addition of Zr4+ ions can cause strain on the lattice to act as an atomic radius of substitutional ion slightly larger than Ti4+ ion. Were also evaluated the addition effects of Ba2+, La3+ and Zr4+ ions on TiO2-anatase-rutile phase transition. The effect of the organic matrix and the different temperatures of infiltration and calcination on the phase transition, phase content and the addition of dopants were investigated, by Scanning Electron Microscopy characterization, X-ray diffraction and Specific Surface Area. We also determined the size of the crystallites by Scherrer equation and the bandgap energy by UV-Vis analysis. The lattice parameters of samples refined by the Rietveld method were determined by JANA2000 program. The radicals generated in photoactivity tests were characterized by Electron Paramagnetic Resonance Spectroscopy. Since the Orange II dye discoloration by-products were evaluated by Liquid Chromatography. The organic matrix microstructure provides for the generation of TiO2 plates, and this increases the microstructure phase transition temperature of anatase to rutile. The anatase phase was majority up to 800 ºC and this above 1000 ºC. The photocatalytic efficiency was effective in all tests (aqueous, gaseous and biological), and much better when compared to commercial powder P25 used as standard.
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Nakao, Cecília Yuriko [UNESP]. "Avaliação da intrusão dos molares superiores pela técnica de ancoragem com miniplacas de titânio." Universidade Estadual Paulista (UNESP), 2004. http://hdl.handle.net/11449/95810.
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A necessidade de recursos para o tratamento da mordida aberta anterior esquelética, em adultos, que apresentam excesso de erupção dentária posterior superior, a deficiência de dados literários e de estudos mais aprofundados sobre o tratamento deste tipo de problema originou o presente estudo.O propósito deste estudo foi o de avaliar o efeito da intrusão dos molares pela técnica de ancoragem com miniplacas de titânio. A amostra de estudo consistiu-se de telerradiografias em norma lateral e a 45 graus, de pacientes adultos com idade entre 13 anos e 5 meses a 29 anos e 8 meses. A seleção da amostra teve como critério de inclusão, pacientes com dentadura permanente, portadores de mordida aberta anterior de pelo menos 1,5 mm e extrusão dos dentes posteriores superiores. Os pacientes foram tratados com força intrusiva aplicada ao segmento posterior bilateralmente, utilizando elástico tissue guard apoiado do tubo do primeiro molar superior ao gancho da miniplaca de titânio. Este procedimento era iniciado quinze dias após a implantação das miniplacas no pilar zigomático da maxila e ativada a cada 15 a 20 dias pela troca do elástico com força de 450 g a 500 g, pelo período de 6 meses. Os dados do estudo mostraram evidências de intrusão verdadeira dos molares superiores com este tipo de tratamento. Pôde ser concluído que as miniplacas de titânio permanecem firmes e estáveis quando utilizadas como ancoragem ortodôntica fixa possibilitando uma intrusão real dos dentes posteriores de pacientes adultos, com resultante alteração na inclinação do plano oclusal no sentido horário e mandibular no sentido anti-horário além de diminuição da altura facial anterior.
The need of resources for the treatment of skeletal anterior open bite in adults with superior posterior dental eruption excess, the lack of information in the literature and elaborate studies about the technique originates this study. The aim of the study was to evaluate the effect of the upper molar intrusion by the titanium miniplates anchorage technique. The sample consisted of lateral and 45 cephalometric radiographs of patients between 13 years and 5 months to 29 years and 8 months of age. The inclusion criteria for selection of the sample was adult patients with permanent dentition, anterior open bite of at least 1,5 mm and extrusion of the posterior upper teeth. The patients were treated with an intrusion force applied to the posterior segment bilaterally by the means of tissue guard elastics tied to the tube of the upper first molars and to the miniplates hooks. This procedure was started fifteen days after the implantation of the miniplates and it was checked each 15 to 20 days for elastic change, with forces varying from 450 to 500 grams/side for six month period. The data collected in the study showed evidence of real upper molar intrusion with this kind of treatment. It was concluded that the titanium miniplates as used as orthodontic anchorage remained firm and stable allowing a real intrusion of the posterior teeth in adult patients, with a resulting change in the inclination of the occlusal plane in the clockwise direction, of the mandibular plane in the counterclockwise direction and in a decrease of the anterior facial height.
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Nakao, Cecília Yuriko. "Avaliação da intrusão dos molares superiores pela técnica de ancoragem com miniplacas de titânio /." Araraquara : [s.n.], 2004. http://hdl.handle.net/11449/95810.
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Resumo: A necessidade de recursos para o tratamento da mordida aberta anterior esquelética, em adultos, que apresentam excesso de erupção dentária posterior superior, a deficiência de dados literários e de estudos mais aprofundados sobre o tratamento deste tipo de problema originou o presente estudo.O propósito deste estudo foi o de avaliar o efeito da intrusão dos molares pela técnica de ancoragem com miniplacas de titânio. A amostra de estudo consistiu-se de telerradiografias em norma lateral e a 45 graus, de pacientes adultos com idade entre 13 anos e 5 meses a 29 anos e 8 meses. A seleção da amostra teve como critério de inclusão, pacientes com dentadura permanente, portadores de mordida aberta anterior de pelo menos 1,5 mm e extrusão dos dentes posteriores superiores. Os pacientes foram tratados com força intrusiva aplicada ao segmento posterior bilateralmente, utilizando elástico "tissue guard" apoiado do tubo do primeiro molar superior ao gancho da miniplaca de titânio. Este procedimento era iniciado quinze dias após a implantação das miniplacas no pilar zigomático da maxila e ativada a cada 15 a 20 dias pela troca do elástico com força de 450 g a 500 g, pelo período de 6 meses. Os dados do estudo mostraram evidências de intrusão verdadeira dos molares superiores com este tipo de tratamento. Pôde ser concluído que as miniplacas de titânio permanecem firmes e estáveis quando utilizadas como ancoragem ortodôntica fixa possibilitando uma intrusão real dos dentes posteriores de pacientes adultos, com resultante alteração na inclinação do plano oclusal no sentido horário e mandibular no sentido anti-horário além de diminuição da altura facial anterior.Abstract: The need of resources for the treatment of skeletal anterior open bite in adults with superior posterior dental eruption excess, the lack of information in the literature and elaborate studies about the technique originates this study. The aim of the study was to evaluate the effect of the upper molar intrusion by the titanium miniplates anchorage technique. The sample consisted of lateral and 45 cephalometric radiographs of patients between 13 years and 5 months to 29 years and 8 months of age. The inclusion criteria for selection of the sample was adult patients with permanent dentition, anterior open bite of at least 1,5 mm and extrusion of the posterior upper teeth. The patients were treated with an intrusion force applied to the posterior segment bilaterally by the means of "tissue guard" elastics tied to the tube of the upper first molars and to the miniplates hooks. This procedure was started fifteen days after the implantation of the miniplates and it was checked each 15 to 20 days for elastic change, with forces varying from 450 to 500 grams/side for six month period. The data collected in the study showed evidence of real upper molar intrusion with this kind of treatment. It was concluded that the titanium miniplates as used as orthodontic anchorage remained firm and stable allowing a real intrusion of the posterior teeth in adult patients, with a resulting change in the inclination of the occlusal plane in the clockwise direction, of the mandibular plane in the counterclockwise direction and in a decrease of the anterior facial height.
Orientador: Ary dos Santos-Pinto
Coorientador: João Roberto Gonçalves
Banca: Tatsuko Sakima
Banca: Hélio Hissashi Terada
Mestre
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Trivellato, Alexandre Elias. "Estudo quimico, macroscopico e da resistencia a flexão de placas e parafusos de titanio usados na fixação interna rigida." [s.n.], 1999. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288692.
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Orientador: Renato MazzonettoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O objetivo deste estudo foi comparar quatro sistemas de placas e parafusos de 2,0 mm utilizados em fixação interna rígida, sendo duas marcas nacionais (Engimplan e Bucomax) e duas importadas (Synthes e W. Lorenz). Foram realizadas as seguintes análises: composição química, através de espectrometria por dispersão de energia (EDS) e espectrometria de emissão atômica (AES), macroscópico através de medidas padronizadas e de resistência à flexão. Os resultados obtidos permitem concluir que as marcas nacionais apresentaram um comportamento inferior, em relação a padronização das dimensões das placas e parafusos avaliados, influenciando nos resultados dos testes de flexão, onde estas se comportaram da mesma maneira. Entretanto, a marca comercial W. Lorenz utiliza liga de titânio-6alumínio-4vanádio para a confecção dos parafusos, fato responsável pelo melhor resultado no teste de flexão, que qualquer outra marca. Os demais parafusos e placas apresentaram, se constituídos de titânio comercialmente puro, de acordo com a EDS 'e posteriormente confirmados pela AES
Abstract: The aim of this study was to compare four 2.0 mm systems of plates and screws of used for internal rigid fixation. From them, two were Brazilian (Engimplan and Bucomax), one made in Switzerland (Synthes), and the fourth one was made in the Germany (W. Lorenz). The following analysis were done in both plates and screws: chemical analysis using Energy Dispersive Spectroscopy (EDS) and Atomical Emission Spectroscopy (AES), measurement of dimensions and bending resistance. The present results allow to conclude that both Brazilian systems evaluated showed a lower behavior in evaluation to the dimensions. The bending assay showed that Brazilian systems were similar. However, in the trademark W. Lorenz the screws are made from titanium-6aluminum-4vanadium alloy, what can be the reason for a better performance in the bending assay compared to the other three systems. The remaining plates and screws are made from titanium commercially pures as confirmed by EDS and AES
Mestrado
Cirurgia e Traumatologia Buco-Maxilo-Faciais
Mestre em Clínica Odontológica
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Calderoni, Davi Reis 1982. "Avaliação do uso de placas sinterizadas de titânio com e sem recobrimento de beta-fosfato tricálcico no reparo de falhas ósseas em calvária de ratos = Evaluation of sintered titanium scaffolds with and without beta-tricalcium phosphate coating for calvarial defects repair in rats." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/312994.
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Orientadores: Paulo Kharmandayan, Ivan Felizardo Contrera ToroTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
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Resumo: Introdução: A reparação de um defeito craniano é um procedimento desafiador, que requer não somente o preenchimento da falha óssea mas também estabilidade a longo prazo do material empregado e restabelecimento do contorno e simetria. Diversos tipos de materiais com diferentes características bem como diferentes métodos de produção dos implantes vêm sendo testados, sem que ainda haja um substituto ósseo considerado ideal. No presente estudo foram investigadas as propriedades de osteointegração de implantes da liga Ti6Al4V construídos por prototipagem com poros tridimensionalmente conectados considerando a influência do recobrimento dos mesmos com uma camada delgada de ?-fosfato tricálcico nestas propriedades. Método: Trinta ratos foram submetidos à criação de defeitos ósseos bilaterais na calvária, que foram preenchidos com implantes, recobertos ou não com ?-fosfato tricálcico, de modo aleatório. Os animais foram distribuídos em grupos e sacrificados 15, 45 e 90 dias após o procedimento. A integração dos implantes foi inicialmente avaliada por ensaio de compressão. A interface osso-implante foi analisada por meio de microscopia eletrônica de varredura. Resultados: A força máxima para produzir o deslocamento inicial dos implantes foi aumentando durante o período estudado, alcançando valores da ordem de 100N para ambos os tipos de implante. Foi observada integração entre o osso e a superfície dos implantes, com crescimento ósseo progressivo no interior dos poros. Não foram observadas diferenças significativas entre implantes recobertos e não recobertos por ?-fosfato tricálcico. Conclusão: Foi alcançada uma adequada osteointegração nas reconstruções cranianas utilizando implantes prototipados da liga Ti6Al4V com as características de porosidade e superfície descritas, sem influência do recobrimento cerâmico adotado. Os resultados sugerem que as características de construção utilizadas podem ser incorporadas aos implantes para reconstrução craniana para melhorar os resultados cirúrgicos
Abstract: Background: The repair of a calvarial defect is a challenging procedure, requiring not only filling of the bone gap but long term stability of the employed material and satisfactory contour and symmetry. Several types of materials with different characteristics have been studied, as well as various methods of implant production. However, to date no ideal bone substitute has been found. The osseointegration properties of porous prototyped implants with tridimensionally interconnected pores made of the Ti6Al4V alloy and the influence of a thin layer of calcium phosphate coating were investigated. Methods: Bilateral critical size calvarial defects were produced in thirty rats and filled with coated and uncoated implants in a randomized fashion. The animals were distributed in groups and kept for 15, 45 and 90 days before sacrifice. Implant mechanical integration to bone was evaluated with a push-out test. Bone-implant interface was analyzed using scanning electron microscopy. Results: The maximum force to produce initial displacement of the implants increased during the study period, reaching values around 100N for both types of implants. Intimate contact between bone and implant surface was present, with progressive bone growth into the pores. No significant differences were seen between coated and uncoated implants. Conclusion: Adequate osseointegration can be achieved in calvarial reconstructions using prototyped Ti6Al4V scaffolds with the described physical characteristics of surface and porosity. The results suggest that the proposed implant design characteristics can be incorporated into calvarial implants to improve reconstructive results.
Doutorado
Fisiopatologia Cirúrgica
Doutor em Ciências
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Guastaldi, Fernando Pozzi Semeghini [UNESP]. "Caracterização físico-química, morfológica, análise mecânica e de elementos finitos 3D, de diferentes placas e parafusos metálicos e técnicas de fixação interna, empregadas em fraturas de ângulo mandibular." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/101067.
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guastaldi_fps_dr_araca.pdf: 2507066 bytes, checksum: a269643c19104677e351a0d2217af1fc (MD5)Proposição: Realizar uma caracterização físico-química, morfológica e comparar o comportamento mecânico de uma liga experimental de Ti-Mo, ao sistema de fixação análogo à base de Ti, em fraturas de ângulo mandibular, favoráveis ao deslocamento. Adicionalmente, análises de elementos finitos 3D foram realizadas para avaliar o padrão de distribuição de tensões nas placas e nos parafusos. Material e Método: Vinte e oito réplicas de mandίbulas de poliuretano foram usadas e uniformemente seccionadas na região do ângulo mandibular esquerdo. Estas foram divididas em 4 grupos considerando o material das placas e as técnicas de fixação interna: grupo Eng 1P, uma placa (zona de tensão da mandίbula) e 4 parafusos de 6 mm de comprimento; grupo Eng 2P, duas placas (uma na zona de tensão da mandίbula e a outra na zona de compressão), a primeira fixada com 4 parafusos de 6 mm de comprimento e a segunda com 4 parafusos de 12 mm de comprimento, sendo todo o material de fixação do sistema 2.0-mm. Os mesmos grupos foram criados para a liga Ti-15Mo. Cada grupo foi submetido a uma carga vertical linear no primeiro molar. As médias e os desvios-padrão foram comparados para avaliação estatίstica (ANOVA; p < .05). Adicionalmente, foi construído um modelo de elementos finitos 3D considerando as mesmas variáveis para avaliar as tensões equivalentes de von Mises (σvM) nas placas e nos parafusos. Resultados: Diferença estatisticamente significativa (p < .05) foi encontrada quando foi realizada a comparação entre ambas as técnicas de fixação (1 e 2 placas), independentemente do material das placas (cpTi and Ti-15Mo). Quando considerado os valores das tensões equivalentes de von Mises (σvM) para...
Purpose: Perform a physico-chemical and morphological characterization and compare the mechanical behavior of an experimental Ti-Mo alloy to the analogous metallic Ti-based fixation system, for mandibular angle fractures, favorable to displacement. Additionally, finite element analysis was performed to assess the stress distribution in the plates and screws. Material and Method: Twenty eight polyurethane mandible replicas were used and uniformly sectioned on the left mandibular angle. These were divided into 4 groups considering the material of the plates and the internal fixation techniques: group Eng 1P, one 2.0-mm plate (tension zone of the mandible) and 4 screws 6 mm long; group Eng 2P, two 2.0-mm plates (one in the tension zone of the mandible and the other in the compression zone), the first fixed with 4 screws 6 mm long and the second with 4 screws 12 mm long. The same groups were created for the titanium alloy (Ti-15Mo). Each group was subjected to linear vertical loading at the first molar. Means and standard deviations were compared with respect to statistical significance (ANOVA; p < .05). Additionally, an three-dimensional finite element model reproducing the characteristics of the specimens used in the mechanical tests were created to evaluate the von Mises equivalent stress (σvM) in the plates and screws. Results: Statistically significant difference (p < .05) was found when the comparison between both internal fixation techniques (1 and 2 plates) was performed, regardless the materials of the plates (cpTi and Ti-15Mo). When considering the von Mises equivalent stress (σvM) values for the comparison between both groups (Eng and Ti-15Mo) with 1 plate, an decrease of 10.5% in the plate and an decrease of 29.0% in the screws... (Complete abstract click electronic access below)
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Dusbaba, Michal. "Návrh a realizace výroby konstrukce zubní náhrady." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241882.
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This thesis deals with a CAD programmed construction design of dental prosthetics and its subsequent production by means of a five axis machine tool. In the theoretical part of the thesis one can find characteristics and analysis of materials designed for a production of dental prosthetics constructions. Among other things, the practical part of the thesis follows up digitization of a patient´s oral cavity part with the use of Trios intraoral scanner representing the latest scanning technology. The obtained data created a basis for a design of the respective dental prosthetics construction using the shape dental system programme called DentalDesigner 2015. Furthermore, the paper deals with a production of a dental prosthetics construction by means of a five axis machine tool and pursues completion works which resulted in the prosthetics final shape. The paper is concluded with discussion comprising a summary of results acquired in the practical part beginning from dental implant introduction to insertion of the made prosthetics construction into the patient´s oral cavity.
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Gonzales, Manny. "The mechanochemistry in heterogeneous reactive powder mixtures under high-strain-rate loading and shock compression." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54393.
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This work presents a systematic study of the mechanochemical processes leading to chemical reactions occurring due to effects of high-strain-rate deformation associated with uniaxial strain and uniaxial stress impact loading in highly heterogeneous metal powder-based reactive materials, specifically compacted mixtures of Ti/Al/B powders. This system was selected because of the large exothermic heat of reaction in the Ti+2B reaction, which can support the subsequent Al-combustion reaction. The unique deformation state achievable by such high-pressure loading methods can drive chemical reactions, mediated by microstructure-dependent meso-scale phenomena. Design of the next generation of multifunctional energetic structural materials (MESMs) consisting of metal-metal mixtures requires an understanding of the mechanochemical processes leading to chemical reactions under dynamic loading to properly engineer the materials. The highly heterogeneous and hierarchical microstructures inherent in compacted powder mixtures further complicate understanding of the mechanochemical origins of shock-induced reaction events due to the disparate length and time scales involved.
A two-pronged approach is taken where impact experiments in both the uniaxial stress (rod-on-anvil Taylor impact experiments) and uniaxial strain (instrumented parallel-plate gas-gun experiments) load configurations are performed in conjunction with highly-resolved microstructure-based simulations replicating the experimental setup. The simulations capture the bulk response of the powder to the loading, and provide a look at the meso-scale deformation features observed under conditions of uniaxial stress or strain. Experiments under uniaxial stress loading reveal an optimal stoichiometry for Ti+2B mixtures containing up to 50% Al by volume, based on a reduced impact velocity threshold required for impact-induced reaction initiation as evidenced by observation of light emission. Uniaxial strain experiments on the Ti+2B binary mixture show possible expanded states in the powder at pressures greater than 6 GPa, consistent with the Ballotechnic hypothesis for shock-induced chemical reactions. Rise-time dispersive signatures are consistently observed under uniaxial strain loading, indicating complex compaction phenomena, which are reproducible by the meso-scale simulations. The simulations show the prevalence of shear banding and particle agglomeration in the uniaxial stress case, providing a possible rationale for the lower observed reaction threshold. Bulk shock response is captured by the uniaxial strain meso-scale simulations and is compared with PVDF stress gauge and VISAR traces to validate the simulation scheme. The simulations also reveal the meso-mechanical origins of the wave dispersion experimentally recorded by PVDF stress gauges.
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Lien, Po-Hsiang, and 連伯祥. "Study of reations of metal powders on titanium plates by microscopic imaging and quenching techniques." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/25385601591526819585.
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碩士國立中正大學
化學工程研究所
91
Using a high-speed microscopic imaging technique observed SHS (self-porpagating high-temperature synthesis) in our laboratory, It is recorded complete reaction process etc. a reactant was heated to fusion ( if reactant was metal powder), reaction started and ended. This experiment involving metal particle and titanium foil reactant has been developed that allows a direct continuous observation of the process. It is found surface reaction of Al-Ti system that has variety of color. The color of varity sequence is light orange of color, dark brown of color, dark red of color , light gray. It was terminated reaction by that opened valve of argon into surface and turned off power supply in each the stage of color the variety. The product by analysis XRD supported that was gussed reaction mechanism. Liquid aluminum was wetted surface of titanium, then which should have reacted with titanium giving rise to a layer of Al3Ti at this time, after, near to the titanium surface which disappears completely. The Ti react with TiAl3 and then induce AlTi and AlTi3, then heated consecutively and the temperature become higher, then AlTi react with Ti induce AlTi3, final product is AlTi3. Nickel power, Iron powder with titanium be heated then wetting surface of titanium. It Observes appearance of surface of titanium is limit change, because light source of the background very strong past observe reaction. Ti react with Fe and then induce FeTi and Ti3Fe react with Ni and then induce Ti2Ni.
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Wang, Szu-Hua, and 王泗華. "The Development and Study of Surface Modified Titanium-based Metallic Bipolar Plates for PEM Fuel Cells." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/62088291024761898596.
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博士中興大學
生物產業機電工程學系所
95
The use of metallic bipolar plate on fuel cell application has been highly expected and pay attention. However, the results of the relative researches were not affirming the achievements. The main reason is the corrosion of the bipolar plates due to the acid aqueous solution produced during the fuel cell operation or the decrease of cell performance due to the formation of metallic ions. In this study, we choose the Titanium (Ti) as the base material for the bipolar plates. By applying the electroplating and sintering methods of the Dimensionally Stable Anode, DSA. The surface of the Titanium bipolar plates were modified by coating with 2.5µm platinum (Pt) layer or sintering 20 g/m2 iridium oxide (IrO2) layer. Platinum (Pt) and Iridium oxide (IrO2) are not only corrosive resistance, but also consist anti-oxidant and perfect electrochemical properties, which are very suitable for being the materials as surface modification of metallic bipolar plates. The results indicated that the optimum operation conditions for the metallic bipolar plates and graphite bipolar plates were totally different. For the metallic bipolar plates, the hydrogen and oxygen fuel must be fully humidified, while the current density and power density of the fuel cell were better under a lower operation temperature. For the graphite bipolar plates, the hydrogen and oxygen fuel only need proper humidified, while the current density and power density of the fuel cell were better under a higher operation temperature. The long term durability testing for different types of bipolar plates were being performed, the results indicated that the main flow field channel of the Titanium bipolar plates single fuel cell had oxidation phenomenon, where the Cathode end was the most serious. Whereas, the electroplating layer of the main flow field channel of the Titanium coating with gold (Au) bipolar plates single fuel cell also had serious corrosion phenomenon at the Cathode end. In fact, the corrosion resistance ability of the bipolar plates sintering with iridium oxide (IrO2), coating with platinum (Pt) and graphite were better. The results also indicated that through the surface modification of the bipolar plates, the corrosion problem due to the acid aqueous solution can be improved; the cost can be lowered, and led to the fuel cell become lighter and thinner.
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CIN, ZIH-EN, and 秦梓恩. "The Optimal Manufacturing Processes and Mechanical Behavior Analysis for Die-Casting Titanium Alloy Plates by Heat Treatment Processes." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/jfvsgk.
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碩士大葉大學
醫療器材設計與材料碩士學位學程
106
Ti-6Al-4V alloy belongs to α+β biphase type titanium alloy and has high strength, low density, corrosion resistance and biocompatibility. Therefore, Ti-6Al-4V alloy is widely used in medical, industrial, aerospace, people's livelihood and so on. Ti-6Al-4V has better toughness, better mechanical strength, and fatigue resistance than pure titanium. It does not react with surrounding tissue and does not react with blood. It has gradually replaced other metal materials in recent years. As the preferred biomedical material for orthopaedic implants, high-strength Ti-6Al-4V alloys are widely used for implants with larger forces. The human body Yang type coefficient 15~30 GPa, the Young's coefficient 98Gpa~110Gpa of the titanium alloy and the stress binding effect when the bones are combined. Therefore, in this experiment, Ti-6Al-4V die castings were used as experimental materials, and then porous patterns were designed on metal materials to reduce the Young's modulus. Avoid the stress shielding effect when titanium alloy implants and bones are combined. The solution heat of the experiment is 1000°C; the cooling methods are air cooling and water quenching respectively, and then 500°C~800°C as the temperature condition of aging heat treatment. Find out the best mechanical properties and process parameters. Therefore, the purpose of the experiment is to perform heat treatment to investigate the Young's modulus and mechanical properties, find the best, and improve the stress shielding effect. In order to understand the mechanical properties, test specimens were made with Ti-6Al-4V, and subjected to heat treatment, tensile test, metallographic observation, hardness test, etc., and the optimum heat treatment conditions and hole design of Ti-6Al-4V were used. The described experiment was performed using the best process parameters to produce the best Ti-6Al-4V spine fusion cage to meet the application of human tissue .
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Chi, Yi-Chun, and 紀宜君. "A Comparison of PLGA and Titanium Plates When Used as a Fixation Material in Fractured Femurs of Diabetic Rats." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/33891067449179401499.
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碩士國立中山大學
生物科學系研究所
98
Titanium bone plates and screws are commonly used in oral and maxillofacial surgery for internal fixation. Although titanium plate is good for fixation of bone fractures, there are still somemany disadvantages of the material. Biodegradable materials are considered to be good alternatives for treatment of the facial bone fractures. Poor wound healing in diabetic animals and human was well known. The aims of the studies were to compare the strength and tissue reaction of the poly lactic-co-glycolic acid （PLGA） with titanium plates used as fixation material in fractured-femora of diabetic and normal animals. The results of the studies show that the wounds of the control group healed quite well and there was no discharge around the wound. However, bullas formation was found in all the diabetic wounds fixed with PLGA. There was fistula with pus and gas discharge around the bullas. In the control group, the diameter of the PLGA-fixed femur was larger than the titanium-fixed femura. There was a large amount of callus formation around the PLGA-fixed fracture femur. At the 20th day, the defects of both groups of the PLGA treated were not healed. A large amount of new bone formation in normal titanium-treated rats was found, while in diabetic rats, mainly a fibrous tissue reaction. At the 40th day, the diabetic PLGA-fixed femora were poorly healed with a large amount of fibrous tissue. Similarly, after 40 days in the titanium-fixed femora of diabetic rats, extensive fibrosis of the defect was also present. In normal PLGA-fixed fractured femora, there was a large amount of cartilage present around the defect. Most of the normal PLGA-fixed fractured femora were distorted in shape. At the 40th day, lamellar bone formation was found around the screw in normal titanium-fixed femora and the defect was healed. In conclusion, the PLGA plate is not suitable for fixation in the fractured-femora of the rats in either normal or diabetic groups when compared with those from titanium plate treat groups. It is because of less strength of the PLGA plate and the material easily cause tissue reaction in the rat which result in the formation of large amount of fibrous tissue around the PLGA screw instead of bone.
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"Metal release from titanium-6Aluminum-4Vanadium posterior cervical spine plates: A computational and experimental study in the canine model." Tulane University, 1996.
Find full textAbstract:
The use of Ti-6Al-4V for spinal implants has increased due to its advantageous mechanical properties, biocompatibility, corrosion resistance, and compatibility with MRI procedures. The release of metal ions or particulates, which can result from mechanical loads imposed on the implant, can affect the degree of biocompatibility of spinal implants, possibly influencing their clinical performance. In this project, the titanium metal release from Ti-6Al-4V posterior cervical spine plates was examined using a computational and experimental approach in the canine model The in vivo titanium metal release from plates implanted in four canines at the C4-C5 level was determined using atomic emission spectroscopy techniques. The highest titanium levels ($>$100 ppm dry weight) were found in tissue samples closest to the screw-plate interfaces. The retrieved implants showed the highest amounts of surface damage at the screw-plate interfaces. The histological evaluation of tissues showed a normal fibrous response with the presence of titanium particulates An accurate and valid three-dimensional finite element model of the canine cervical spine (C3 to C6), plate, and screws was developed, which included contact definitions at the screw-plate interfaces and at the plate-bone interface. This model simulated an average physiologically loaded canine neck and showed that the highest values of all the mechanical parameters evaluated were at the screw-plate interfaces. Wear, fretting, spalling, and stress-enhanced ion release were postulated as candidate metal release mechanisms A model was proposed describing the mechanisms of metal release taking place in a plate-screw type implant in the spine. The highest areas of titanium concentration are at the screw-plate interfaces and the areas of low titanium concentration are at the central portion of the plate. The majority of the titanium detected at the high areas is proposed to be released by fretting and wear at the screw-plate interfaces, and at the center of the plate by mechanisms related to the static nature of these implants, such as dissolution of the passive oxide layer, by diffusion of metal ions through this layer, or by diffusion from the high concentration areasacase@tulane.edu
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Chen, Yi-Ming, and 陳浥洺. "STUDY ON PREPARATION OF TITANIUM DIOXIDE THIN FILMS ON GLASS PLATES BY SOL-GEL METHOD FOR DECOMPOSITION OF DYE WASTEWATER." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/66278755662544809674.
Full textAbstract:
碩士大同大學
化學工程學系(所)
96
The nano-scale titanium dioxide has been recognized as a promising technology to treat wastewaters containing refractory organic compounds. There are many researches in related topics nowadays. One of the objectives in this study is how to immobilize the titanium dioxide for heterogeneous applications. We prepared TiO2 thin films coated on glass plates used as photocatalytic to decompose dye in aqueous solutions. The preparation included the sol-gel method, followed by coating, drying, and calcination. Some factors will affect the performance of the thin films such as i-PrOH/TTIP volume ratio, drying time, calcination time, calcination temperature and coating times were investigated. The conversion of azo dye decomposition in wastewater under 8W UV illumination for 1 hours was measured to identify the efficiency. Several titanium dioxide photocatalyst coated on glass plate were prepared under the same conditions and a series of dye decomposition kinetic study was conducted. The factors of study include agitation speed, initial azo dye concentration, initial pH and reaction temperature. The dye decomposing efficiency performed in a batch reactor with UV light was used to evaluate the optimal preparation conditions. The proper conditions of photocatalytic for i-PrOH/TTIP volume ratio is 5, coating times is 15, drying time is 15 minute, calcination temperature is 400℃, and calcination time is 0.5 hr. A revised kinetic mechanism and model proposed from literature was introduced to describe the kinetics for dye decomposition. The simplified explicit reaction rate derived in this study can fit the experimental data with a good agreement. The better understanding of the photocatalytic kinetics and the operative conditions for the process could give great opportunities for its application to the destruction of environmental organic contaminants.
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Tanas, Francesco. "Tratamento das fraturas condilares e subcondilares." Master's thesis, 2017. http://hdl.handle.net/10284/6338.
Full textAbstract:
A traumatologia é uma das patologias mais frequentes da área maxilo e crânio facial.
Este trabalho tem como objecto o estudo das fracturas condilares, a classificação delas e o
tratamento conservador e médico-cirurgico, através da utilização de vários tipos de placas de
fixação (rétas, trapezoidais, a lambda ou y, e a grelha).
Para a realização desta revisão foram consultados vários textos e artigos científicos sobre o
argumento, utilizando as seguintes palavras-chave: “fraturas condilares”, “fraturas subcondilares”,
“tratamento cirurgico das fraturas condilares”, “placas de titânio”, “osteosíntese”, “placa lambda”,
“placa trapezoidal”, “placas 3D”.Condyle’s trauma in the last few years has been the subject of numerous studies and clinical tries. This job has, as its goal, the study of condylar fractures, their classification and its medical and surgical treatment, through the most current techniques. To do this research many texts and scientific articles concerning this topic have been consulted, using these keywords: “condylar fractures”, “subcondylar fractures”, “surgical treatment of condylar fractures”, “titanium plates”, “bone synthesis”, “lambda plate”, “trapezoidal plate”, “3D plates”.
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Yang, Zong-Lin, and 楊宗霖. "Transient liquid phase bonding of aluminum / titanium plate." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/z7zd79.
Full text
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He, Yu-Jou, and 何羽柔. "Effect of Thread Profile on Fatigue Strength of Titanium Locking Plate (Notch effect of titanium)." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/6acs2h.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
105
Locking plates have been widely used in all kinds of bone fracture surgery. The stiffness and stability of locking plates are well-performed in comparison to traditional dynamic compression plates, because the threads of locking plates fix plates and screws tightly. The most common failure of locking plates is fatigue breakage. The failure initiation of locking plates always occurred at the thread hole around the fracture gap, and threads may cause notch effect which reduce the fatigue strength of material significantly. Titanium alloy is commonly used materials in locking plate systems, but its fatigue strength is apparently reduced by high notch sensitivity. Therefore, the purpose of present study is to investigate the effect of thread profile on fatigue strength of titanium-alloy locking plates (the notch effect of the titanium alloy). In biomechanical testing, locking plates having four different thread profiles were tested for fatigue strength. In finite element analysis, a 3D finite element model simulated the situation of biomechanical testing. Consequently the maximum tensile stress were calculated and compared with the biomechanical testing results. From the results of biomechanical test and finite element analysis, the notch effect occurred at the tip radius of threads. Removing the threads in tension sides might reduce the notch effect of titanium-alloy plates and increase 802% fatigue life comparing with type1. It was also known that the threads had no significant effect on notch effect in compression sides. There was no significant effect on notch effect by enlarging the root radius of the threads. By reducing the maximum outer diameter of the holes, the fatigue life was only improved slightly. Hence, the best design in present study was that removing the thread in tension sides.
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Hsu, Pin-Hsin, and 許瀕心. "Development of the customized pre-bent orbital titanium plate." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/29260230030682051484.
Full text
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Hu, Ho-Chieh, and 胡賀捷. "Preparation of Titanium Dioxide Thin Film on Alumina Plate." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/27639348192656185951.
Full textAbstract:
碩士國立臺灣大學
化學工程學研究所
89
The titanium dioxide thin film, which is spin-coated on alumina plate, is prepared by sol-gel method using tetraisopropyl titanate (abbreviated as TPT) as precursor. The research is focused on the effect of sol composition, mixing procedure, stirring time and surface modification of alumina plate on film structure and electrical resistance. It is found that adding acid agent in sol can make the grain size of film smaller and more uniform, consequently the film resistance is lower. When preparing sol, the stirring time must be suitable. If the TPT and acid agent were diluted separately before mixing, we can get a film with lower resistance after coating the sol on the substrate. There are two main effects on surface treatments of alumina plate. First, the surface treatments help to smooth the surface of alumina plate. Second, the surface treatments will increase the hydroxyl groups on the surface, thus make the grain size of the TiO2 film larger. As a result, we can get the thin film with lower resistance by coating on alumina plate which has been treated with dilute a base solution for a long time. It is found that both controlling the humidity of the environment during coating process and making the film thicker by coating more than one layer can both lower the resistance of the prepared thin film.
34
Hsieh, Fan-Chun, and 謝汎鈞. "The technical development of Titanium alloy's plate screener using electrochemical machining." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/86845719350464965813.
Full textAbstract:
碩士國立中央大學
機械工程研究所
90
The project presents a numerical for predicting the anode shapes in the electrochemical machining with prescribed tool shape. The conductivity of, and the variation of electrolyte conductivity with temperature had been taken into account in numerical simulation. Results show that the accuracy of the predicted shape is improved.
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LIN, MIN, and 林旻. "Study of polymeric film covered titanium plate assisted laser surface treatment." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/5423zf.
Full textAbstract:
碩士國立雲林科技大學
機械工程系
106
In the relevant literature read, I learned that the traditional method of heat treatment is not only time-consuming but also can not accurately control the local surface. In today's industry, lasers can replace many of the more complex and time-consuming processing. In literature search, it is understood that the modification of the metal surface by laser has gradually become a trend, and carburizing effect can be achieved with a minimum of resources in a short period of time, which is a great progress for the future heat treatment. In this study, laser-carburized and laser-shot-peened pure titanium plates were fabricated using 1064nm diode laser. Before the start of the experiment, the laser needs an additional range finder to ensure that it can be engraved at a fixed focus position for each experiment, and the Power meter is used to confirm that the laser power (18W) (20W) text match, the measurement shows the results, the laser power attenuation of 10%. In this study, under the same medium layer and overburden, the set of engraving parameters are divided into different speed and power, the speed is divided into five kinds, the power is divided into four kinds, a total of twenty groups of parameters. The media used in this study can be divided into flake solids, powders, and mixed solutions. The media used in the experiment all have one thing in common is carbon. These media are double-sided adhesive, toner, black paint and toner plus the solution of the solvent, after all, carbon-based research is an indispensable element. The coverings used in this study are all sheet-like solids. The overlayers are mainly used to limit the flow of the medium. The main purpose of this study is carburizing. In order to increase the carburization without disturbing the laser engraving process, Effect, solid cover easy to choose a transparent and containing carbon polymer plastic film as a cover. In addition to the results of engraving on the surface of the test piece after the engraving, the study needs to analyze the engraving results through SEM, EDS, HV hardness tester, white light interferometer and XRD in more detail to confirm the main part of this study purpose.
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Kan, Min-Yu, and 甘旻諭. "Research and Development Grind titanium plate in anode electroltie plate forOzone Generation with PEM Water Electrolyzer Technology." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/fva4m2.
Full textAbstract:
碩士元智大學
機械工程學系
106
This research anode electrolytic plate for Sintered titanium grinding. In water electrolyzer ozone generation, the performance of anode is limited by the anode’s materials and dynamics. Due to this limitation, high voltages are necessary to produce ozone. In addition, it is bad to transmit electric current and current persistent short for further ozone generation. The characteristics of anode catalysts are determined through Field-Emission Scanning Electron Microscope, Energy Dispersive Spectromete to analyze performance of different resist layer.
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Liu, Jian-Hong, and 劉建宏. "Deposition of Hydroxyapatite on Titanium Plate by Microarc Anodizing and Hydrothermal Treatment." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/28428042063678315619.
Full textAbstract:
碩士國立臺灣大學
材料科學與工程學研究所
93
Calcium and phosphorus-containing oxide film was made on commercially pure titanium plate using a microarc discharging oxidation method. The microstructure of the oxide film was characterized by cross-sectional transmission electron microscopy (TEM). Hydrothermal treatment was then performed on the oxide film for the precipitation of hydroxyapatite. Upon galvanostatic anodizing up to 350V at a current density of 50 mA/cm2 in the electrolyte consisting of β-glycerophosphate disodium(β-GP) and calcium acetate, microarc discharge was observed on titanium plates, leading to the formation of an oxide film mainly composed of anatase, and calcium and phosphorus species. Once microarc discharge occurred during anodizing, relatively large craters were observed on the oxide film, which generally comprised two layers:an outer overlay containing significant amount of Ca and P in a mixture of amorphous oxide and nanocrystalline anatase, and an inner oxide layer dotted with micropores contacting the substrate. Moreover, as the front of the oxide film propagated toward the substrate, these micropores tended to coalesce into cavities residing at the interface between the outer and inner layers. The oxide film contained more Ca and P, but lower Ca/P ratio, and displayed less crystallinity with increasing solution b-GP concentration. Both acetate and hydroxyl ions can enhance microarc discharging, while resulted in oxide films with different morphologies and crystal structure. Hydroxyapatite precipitates on the porous oxide film were nonuniform after 2 h of hydrothermal treatment at 300℃. In contrast, introducing sodium hydrocarbonate to hydrothermal treatment solution led to the formation of high density hydroxyapatite precipitates with improved crystallinity.
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Huang, Jun-Ren, and 黃駿仁. "Screw Head Plugs Increase Locking plate Fatigue Strength in 316L but not in Titanium." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/76514454156672024724.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
104
Locking plate is widely used for the treatment of various kinds of bodily fractures. Locking plate can provide more stiffness and stability than dynamic compression plate, because its locking screw can lock on plate by thread hole. Fatigue breakage was the most commonly seen mode of failure and mostly occurs through the screw holes around the fracture site. The purpose of this study was to increase the locking plate fatigue strength with screw head insertion. And to investigate if the screw head insertion can improve notch effect in titanium alloy plate. In biomechanical testing, plates were tested for both stiffness and fatigue mechanical properties. In finite element analysis, three-dimensional plate model used same structures and conditions with those applied in the biomechanical tests. After processing, the von-Mises stresses and displacement were recorded and correlated with the mechanical test results. From the results of biomechanical test, plugging the empty holes could increase the fatigue life of the stainless steel plates but not in titanium alloy plate. The insertion torque was increased from 4 Nm to 12 Nm, the stainless steel plates fatigue life could also be increased, but the differences were still not significant. In the finite element analysis, plugging the empty holes did not decrease the von-Mises stress. The micro Vickers-hardness shows that the stainless steel plate work hardening occurs after screw head insertion but not in titanium alloy plate.
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Butler, Chad L. "The application of ablative laser ultrasonics to an aluminum plate, titanium tube, and welded joints." Thesis, 1996. http://hdl.handle.net/1957/34279.
Full textAbstract:
Laser ultrasonics can be used to nondestructively evaluate structures to determine the existence and location of surface and interior flaws. The goal of this research was to determine if laser ultrasonic techniques can be applied to the inspection of aluminum plate. titanium tubes, and large welded plate structures. The research was carried out with a Q-switched pulsed ruby laser emitting light of 694 nm wavelength. Ultrasonic waves were experimentally generated and recorded in the aluminum plate and the titanium tube. A comprehensive literature study was completed to determine if the technique can be applied to welded structures. For the two experimental cases, the ultrasonic waves were received by a piezoelectric pinducer which was located on the opposite side of the plate. and on the outside of the tube. A digital oscilloscope captured the signals from the pinducer. The signals were then analyzed to determine echo spacing and frequency content. The physical characteristics of the laser pulse such as the energy and full-width-half-height and amplitudes were measured via a photodiode system and a calorimeter. The aluminum plate confirmed that the system was functioning properly, as the ultrasonic echoes that were generated matched the expected results from previous experimentation. The titanium tube data turned out to be difficult to interpret due to the complex geometry and mode conversion. The welding research showed that ultrasound can be used to identify many types of flaws in a welded joint. Currently, few researchers have applied the laser based ultrasound to flaw detection in finished welds, although several have looked at using the laser ultrasound as an input to a control system for a weld in progress. The literature research uncovered the need for further studies on the application of laser based ultrasound to flaw detection in completed welds.Graduation date: 1997
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Lin, Pei-Ru, and 林佩儒. "The effect of the Voltage Level on Hydroxyapatite Coating of Titanium Plate by Micro-arc Oxidation." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/11247485424189939161.
Full textAbstract:
碩士大同大學
材料工程學系(所)
98
Hydroxyapatite crystallite has successfully been deposited on titanium plates by micro-arc oxidation in this work. The electrolytic solution is composed of mixture of electrolytic solution and 10g/L hydroxyapaite powders with 10% alcohol solution in this experiment. The electrolytic solution contains 0.075M Ca(CH3COO)2•H2O,0.025M Ca(H2PO4)2•H2O,0.04M EDTA-2Na and 0.375M NaOH. Different voltage is employed on titanium plates which immersed in electrolytic bath to observe the characteristic of surface on hydroxyapatite coating. As voltage at the interval of 275 to 325V, the crystallinity of hydroxyapatite crystal increased with increasing voltage and the primary phases are hydroxyapatite and anatase , as shown in XRD patterns. However, the high power input will also incur ablation and crack. On the other hand, the thickness of coating also increased with increasing voltage and became more uniform .Hence, increase voltage lead to the increase in the roughness on surface of coating. The porous structure on surface exhibits better hydrophilic property and smaller water contact angle. The number of micropores increase as voltage increase, indicative of smaller water contact angle. The microarc oxide coating seemingly bears no significant relation with voltage, but affected by other factors, such as deposition rate. The increase of deposition rate might be increase the growth rate of coating but decreased the quality of coating.
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Lee, Yong-Rong. "The Research of Clinical Relationship Between the Complications of the Titanium Reconstruction Plate and Their Risk Parameters." 2008. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-0406200815434100.
Full text
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Shine, Han-Jiue, and 薛涵覺. "Study on the Micro-Arc Oxidation Grown Anatase TiO2 Films on Titanium Plate and Their Photocatalyst Effciency." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/raayqc.
Full textAbstract:
碩士國立臺北科技大學
材料及資源工程系研究所
98
Micro-arc oxidation technology in the last ten years to develop quite rapidly, because of its process is easy and simple, water less, waste less, while the electrolyte does not contain Cr6 +, Pb2 + and so on hazardous substances to conform to environmental protection requirements. The results indicate that micrometer-scale porous anatase TiO2 film can be fabricated by Micro-arc oxidation, and by micro-arc oxidation treatment after the surface of the specimens showed porous appearance, which can effectively increase the surface area of TiO2 films. The process will produce high-energy arc can be generated quickly in the surface of metal oxide film, in addition to to save process time, but also increase the crystalline oxide film, and can generate porous anatase TiO2 film. In this study, interest in using micro-arc oxidation of titanium plate were prepared on TiO2 thin films, to change the electric current, discharge voltage and frequency, and try different doping concentration of Fe3 +, and then test Photocatalys activity of TiO2 thin films by methylene blue decomposition. The results showed: Enhance the voltage to make the internal anion in-depth, and thickness for the phase changes are obvious, so the main difference will be reflected on the phase and thickness. When the voltage value of 300 V when the degradation rate of 47% available. Enhance the current value would only anions accumulate in the surface, the inner depth is not easy, so the effect of increasing the film thickness is limited, so the main difference will be reflected in the topography. When the current value of 0.25 A obtained when 59% of the degradation rate. In order to maintain the flat surface of film, it is necessary to impose pulse. And the higher the frequency the more flat film surface, but after more than 550 Hz will reduce the film thickness. When the applied frequency is 550 Hz when the degradation rate of 65% available. The longer micro arc oxidation film surface will become rough, but more than 30 minutes will begin to tend to flat the surface. When the micro arc oxidation time of 50 minutes the degradation rate of 56% available. Doped by impurities in the electrolyte layer to improve the photocatalytic oxidation is feasible, When Fe3+ doping capacity of 0.1 g/L the degradation rate of 68% available. However, the electrolyte used in this study as oxalic acid, easily react with FeCl3, so up to 0.4 g/L on the contrary will result in the degradation rate of decline. In short, use oxalic acid as the electrolyte does not apply to micro-arc oxidation of practical use in this regard, but is used to study oxidation as the effect of various parameters of subjects might be feasible. Also can confirm that the doping by impurities in the electrolyte change generate the nature of titanium dioxide thin films is feasible.
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Wu, Ming-Feng, and 吳明峰. "The Study of the Fabrication Parameters of Micro-arc Oxidation on Hydroxyapatite Coating on Pure Titanium Plate." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/25393134650693236155.
Full textAbstract:
碩士大同大學
材料工程學系(所)
98
TiO2-based coatings were prepared on pure titanium by micro-arc oxidation (MAO) in an electrolytic solution containing Ca(CH3COO)2．H2O, Ca(H2PO4)2．H2O, EDTA–2Na and NaOH. SEM/EDS and XRD were adopted to investigate the microstructure, elements distribution and phase composition of the coatings prepared in the above electrolytes. Macro-porous titania-based coatings were formed on the titanium substrates at various voltages, charging times, duty ratios, Ca/P ratios, and concentrations of NaOH. The phase, Ca and P content, morphology, and thicknesss of the coatings were strongly dependent on the applied voltage, Ca/P ratio and concentration of NaOH. In particular, HA- and CaTiO3-containing coatings were produced at higher Ca/P ratio and concentration of NaOH. With increasing applied voltage from 260V to 320V, the thickness, roughness of the coatings and the crystallinity of HA and CaTiO3 increased; the rutile phase was formed in the coatings with anatase phase. EDX analysis shows that Ca and P elements tend to present primarily in the region of the coatings.
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Lee, Yong-Rong, and 李昀融. "The Research of Clinical Relationship Between the Complications of the Titanium Reconstruction Plate and Their Risk Parameters." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/38470082630340454184.
Full textAbstract:
碩士國立臺灣大學
臨床牙醫學研究所
96
The appropriate reconstruction for the mandibular defect after oncological resection is one of the most challenging area of head and neck surgery. The titanium reconstruction plate is one of the most popular material used in oral and maxillofacial reconstruction. However, many complications such as plate exposure, plate fracture, infection, or bony nonunion could restrict the application of reconstruction plate and more expensive treatment cost. So that the research for the relationship between the complications of titanium reconstruction plate and their clinical risk factors could provide some suggestions for improvement of clinical use of reconstruction plate. There are already some studies published for discussing this issue, but there is still not a study to compare the data of the patients in north Taiwan with other places. So we collect all patients with titanium reconstruction plate reconstruction after oncological resection in the Department of Oral and Maxillofacial Surgery, National Taiwan University, from 1995 to 2007. Total 146 cases were included in our study. The clinical risk factors were collected in three separated groups- Preoperative (Age, gender, diagnosis, preoperative radiotherapy, and BMI), intraoperative (The date of surgery, size of defect, brand of plate, screw numbers, bone graft, soft tissue graft, type of plate), and postoperative (Postoperative radiotherapy, postoperative remained occlusion, complications, follow up duration). Then all data were analyzed with chi-square test, univariate analysis, and Cox proportional hazard regression model. We also introduced Kaplan-Meier survival rate graphs to describe the relationship between complications and risk factors. The results showed that- First, the age and the diagnosis were two strongly independent factors. The younger patients have better tissue recovery capacity, so that the complication rate would be less than the more elderly group. Then the osteoradionecrosis and malignant group showed higher complication rate than the benign group. Second, our results also agreed with that the post-oncological soft tissue graft could provide sufficient volume of tissue coverage and better plate tolerance. Third, the secondary bone reconstruction should be performed as early as possible especially for the patients with postoperative remained occlusion. Fourth, the Leibinger reconstruction plate would provide better tensile strength tolerance to resist the bending induced metal fatigue and further plate fracture than the Mondeal group. Fifth, both the pre- and post-operative radiotherapy induced higher complication rate. Sixth, our study also suggested that enlargement of the internal thread of screws or change the configuration of the screwholes to rectangular or square could improve the torsion moment distribution. In conclusion, if we could prevent the avoidable risk factors intra- and post-operatively, the titanium reconstruction plate could also provide acceptable functional and aesthetic restoration for temporal or permanent reconstruction for the patients whose conditions could not tolerate long time reconstruction surgery. The titanium reconstruction plate could also be an effective alternative reconstruction material.
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Li, Hing-fang, and 李幸芳. "Study on the Micro-Arc Grown Anatase TiO2 Films on Titanium Plate and Their Sensitized Solar Cell Efficiency." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/88397260981238642853.
Full textAbstract:
碩士逢甲大學
材料科學所
95
In past years, metallic materials have been regarded as main materials in traditional industry. However, the demand has been gradually replaced from metallic materials to light and functional metals and alloys with high commercial value. Among these functional metals, titanium has attracted much attention due to its extremely good corrosion resistance, high strength, light weight and good ductility, etc. However, in form of titanium dioxide, it has been applied in semiconductor sensor, bactericidal photo-catalytic materials and dye-sensitized solar cell (DSSC) all based on its photocatalytic property. It is known that titanium dioxide had a wide energy band gap and its microstructure fabricated by micro-arc oxidation (MAO) dominated photovoltaic efficiency of the DSSC. It is expected to produce an ideal TiO2 electrode with larger specific surface area on the titanium surface and capable of absorbing dye efficiently. However, microstructure could be changed by means of different ways such as heat treatment (usually for 400-600 ℃) that could affect phase structure of oxide layer and acid-pickling that could change its surface morphology or get rid of surface impurity. In this study, the porous anatase titanium dioxide thin film was grown on the titanium thin plate by MAO. Then the Ti / TiO2 +N3 dye / I2+LiI electrolyte / ITO inversed-type solar cell device was constructed. In this study, microstructure of micro-arc oxided titanium dioxide films and post acid-pickling were studied. Photovoltaic efficiency of the assembled DSSC devices was evaluated. The results indicate that micrometer-scale porous anatase TiO2 film can be fabricated by MAO and predominantly composed of anatase phase and minor rutile phase. By increasing current density, oxide film thickness is increased. This allows absorption of dye more efficiently. The overlarge current density led to decrease the amount of anatase phase. The effect of voltage on photocurrent is proportional to current density. When MAO treatment time was extended under low current density of 0.05 A/cm2, oxide layer thickness gradually reaches a constant value and the corresponding short-circuit photocurrent gradually increases to a constant value about 9.5 µA/cm2. However, in constant voltage of 500 V, the extended the MAO treatment time results in excess joule heating and large amount of rutile structure is created. This significantly decreases the short-circuit photocurrent from 11 µA/cm2 for 10 min to 2 µA/cm2 for 120 min. The acid-pickling, gives rise to the change in surface morphology. However, with increased acid-pickling time in sulfuric acid solution, surface morphology also gives significant change. Acid-pickling for 72 h, surface blossomed into the submicron surface morphology and it is good for dye absorbing and performs the highest short-circuit photocurrent�nof�n��5 �n�嫀/cm2. In summary, anstase titanium dioxide film can be fabricated on titanium plate by MAO. Micrometer scale porosity gives short-circuit photocurrent about ��5 �n�嫀/cm2 after parameter and acid-pickle.
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[Verfasser], Bancha Chernchujit. "Arthroscopic reconstruction of the coracoclavicular ligaments with suture anchors and small titanium plate : a comparative biomechanical study / Bancha Chernchujit." 2004. http://d-nb.info/972588663/34.
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Hugo, Victor Emmanuel. "A study of titanium-bearing oxides in heavy mineral deposits along the East Coast of South Africa." Thesis, 1993. http://hdl.handle.net/10413/5647.
Full textAbstract:
Heavy mineral deposits along the east coast of South Africa represent the world's largest
demonstrated resource of beach placer ilmenite. This mineral occurs as homogeneous,
subrounded grains, with chemical compositions close to pure FeTi03• Concentrates
contain between 48 and 52 per cent Ti02, with minor impurities of MnO, MgO, and
Cr203.
Most coastal ilmenites are unaltered or display only incipient alteration, but the entire
spectrum of alteration products from ilmenite to rutile or anatase, is observed.
Transmission electron microscopy of weathered ilmenites reveals that ilmenite commonly
alters to pseudorutile and then to rutile or anatase, as described by Teufer and Temple
(1966) and Grey and Reid (1975). Ilmenite may also alter directly to rutile (or anatase)
in a single-stage process. In addition, ilmenite altered by high temperature oxidation and
hydrothermal processes is found in the deposits. There is good mineralogical evidence that
the alteration of ilmenites found in the coastal sediments is best described by a multi stage
model, in which some ilmenite grains were altered prior to final deposition.
Other common iron-titanium oxides in the deposits include magnetite, rutile and hematite,
which may occur as discrete grains or as composite grains of two or more oxides.
Ilmenite and magnetite in the coastal sediments are derived from rocks of both the Karoo
Igneous Province and the Natal Basement, while rutile is derived solely from the latter.
Ilmenites from certain rock groups may be distinguished on the basis of their chemical
composition. However, magnetite chemistry is a better indicator of provenance, and
magnetites from the above two sources can be clearly distinguished. The petrography of
the iron-titanium oxides may be used as a provenance indicator, but may be misleading,
as the proportions of the oxide intergrowths change with transport and weathering.
Variations in the proportions and chemical compositions of iron-titanium oxides and other
heavy minerals within the coastal sediments are caused by provenance, selective sorting
during deposition, age of the deposit, weathering, and the recent geological history of the
area. A model is proposed in this study which describes the formation of the heavy
mineral deposits in relationship to the above influences.Thesis (Ph.D.)-University of Natal, Durban, 1993.