Hipótese do estudo: A presente pesquisa hipotetiza que a técnica de cimentação está diretamente ligada a resistência adesiva de restaurações indiretas. Objetivos: O presente estudo experimental verificou se o selamento imediato da dentina, com diferentes sistemas adesivos, apresentaram melhores resultados de resistência de união junto a cimentação resinosa de restaurações indiretas. Métodos: Foram utilizados 48 terceiros molares humanos, divididos em seis grupos de acordo com as técnicas de cimentação testadas: grupo 1) Sistema Variolink II (Ivoclar Vivadent); grupo 2) Clearfill SE (Kuraray) + Variolink II; grupo 3) Selamento com Clearfill SE + Sistema Variolink II após 24h; grupo 4) Selamento com Exite DSC (Ivoclar Vivadent) + Sistema Variolink II; grupo 5) Selamento com Clearfill + Tetric Evo Flow (Ivoclar Vivadent) + Sistema Variolink II após 24h; Grupo 6) selamento com Exite DSC + Tetric Evo Flow + Sistema Variolink II após 24h. Oito amostras de cada grupo foram para máquina de cortes seriados (Isomet 1000) para obtenção de palitos com 1mm2 de área. Os palitos de cada grupo foram submetidos ao teste de microtração. O teste de microtração foi utilizado após 24h da cimentação. Os dados foram estatisticamente analisados pelo teste de Kruskal-Wallis e o teste de Dunn (5%). Diferenças significativas foram detectadas (p=0,0074). Resultados: Os grupos 1 e 2 apresentaram mediana de resistência de união intermediária, sendo estatisticamente semelhantes aos demais grupos. O grupo 6 apresentou mediana significativamente mais alta que os grupos 3, 4 e 5, os quais foram semelhantes entre si. Adicionalmente os tipos de fratura foram analisados com auxílio de lupa estereoscópica, em todos os grupos a porcentagem de fraturascoresivas em dentina ou mistas foi menor em comparação as fraturas adesivas e coesivas em cerômeros. Conclusão: O selamento imediato da dentina com adesivo de condicionamento total junto a resina flow demonstrou maior resistência adesiva. / Hypothesis of the study: This study hypothesizes that the cementation technique is directly related to the bond strength of indirect restorations. Objectives: The present experimental study examined whether the immediate dentin sealing with different bonding systems, the best-performing bond strength in the resin cementation of indirect restorations. Methods: A total of 48 human third molars was divided into six groups according to the techniques of tested: group 1) Variolink System II (Ivoclar Vivadent), group 2) Clearfill SE (Kuraray) + Variolink II, Group 3) with Seal Clearfill SE + System Variolink II after 24h, group 4) Sealing successfully DSC (Ivoclar Vivadent) + Variolink System II, Group 5) Sealing with Clearfill + Tetric Evo Flow (Ivoclar Vivadent) + System Variolink II after 24h, Group 6) sealing successfully DSC + + Tetric Evo Flow System Variolink II after 24h. Eight samples of each group were machine serial sections (Isomet 1000) to obtain sticks with 1 mm2 in size. The sticks of each group were subjected to microtensile testing. The microtensile test was performed used after 24h of cementation. The data were statistically analyzed by Kruskal- Wallis test and Dunn (5%). Significant differences were detected (p = 0.0074). Results: Groups 1 and 2 had a median of intermediate bond strength, being statistically similar to other groups. The sixth group median significantly higher than groups 3, 4 and 5, which were similar. Besides the types of fracture were analyzed with the aid of a stereomicroscope. Conclusions: The immediate detin sealing with total etch adhesive and the flowable resin showed higher bond strength.

O propósito deste estudo foi avaliar a influência de protocolos de secagem do canal na resistência de união (RU) e no selamento apical (SA) de obturações com AH Plus, Sealapex e MTA Fillapex. Cento e cinquenta e seis raízes de caninos superiores foram submetidas à biomecânica com sistema Reciproc (R50) e distribuídas de acordo com o protocolo de secagem (PS): GI- cones de papel; GII- álcool isopropílico 70% + aspiração com pontas NaviTips; GIII- etanol 95% + cones de papel; GIV- EndoVac + cone de papel. Cada grupo foi dividido em subgrupos conforme o cimento obturador: A- AH Plus; B- Sealapex; C- MTA Fillapex. Utilizou-se para todos os espécimes técnica de obturação do cone único. As raízes de cada subgrupo foram destinadas à avaliação do SA (n=8) e RU (n=5), por meio do método de filtração de fluidos (FF) e push-out (PO), respectivamente. Para o PO as raízes foram seccionadas e um slice de cada terço submetido ao teste e à análise do tipo de falha. Os dados foram submetidos aos testes Anova two-way e three-way e Tukey por meio dos software SPSS 15.0 e SigmaStat 3.5 (&alpha;=5%). Os resultados da FF mostraram diferença significante entre os cimentos MTA e Sealapex (p<0,05). O SA não sofreu influência dos protocolos. Na RU não houve diferença entre os terços do canal (p>0,05), mas houve entre os cimentos (p<0,05), protocolos (p<0,05) e na interação cimentos/protocolos (p<0,05). O AH Plus (1,39±0,60) apresentou os maiores valores de RU em relação ao Sealapex (0,83±0,33) e MTA (0,76±0,34). Espécimes secos com álcool isopropílico proporcionaram aos cimentos testados maior resistência de união que quando secos com etanol (p=0,005) e EndoVac (p=0,002). Canais secos com etanol não influenciaram os cimentos. O uso de cones de papel, EndoVac e álcool isopropílico e obturação com AH Plus apresentaram os maiores valores RU que os demais cimentos. Concluiu-se que a infiltração ocorrida com o AH Plus foi semelhante a dos demais cimentos. O AH Plus apresentou os maiores valores de RU. No terço cervical houve predominância de falhas coesivas e de mistas nos demais terços. / The purpose of this study was to evaluate the influence of drying protocols in the bond strength (BS) and in the apical sealing (AS) of teeth filled with AH Plus, Sealapex and MTA Fillapex. One hundred and fifty-six roots of maxillary canines were subjected to biomechanical preparation with Reciproc (R50) and hand out according to the drying protocol (DP): GI-paper points; GII-70% isopropyl alcohol + aspiration with NaviTip points; GIII-95% ethanol + paper points; GIV-EndoVac + paper points. Each group was divided into subgroups according the used sealer: A- AH Plus; B- Sealapex; C- Fillapex MTA. The single cone obturation technique was used for all the samples. The roots of each subgroup were intended for the evaluation of the AS (n = 8) and the BS (n = 5) by using the fluid filtration (FF) and the push-out (PO) methods, respectively. Regarding the PO, the roots were sectioned and a single slice from each third was subjected to testing and also analysed for the type of failure. Data was submitted to the Tukey, two-way and the three-way variance analysis (ANOVA) resorting the SPSS 15.0 and the SigmaStat 3.5 (&alpha;= 5%) software. The results of the FF revealed a statistical significant difference between the MTA and the Sealapex (p <0.05) sealers. The AS showed no influence of the protocols. When it comes to the BS there was no statistical significant difference between the canal thirds (p> 0.05), but there was between the sealers (p <0.05), the protocols (p <0.05) and in the interaction between the sealers and the protocols (p <0.05). AH Plus (1.39 ± 0.60) revealed the highest BS comparing with Sealapex (0.83 ± 0.33) and MTA (0.76 ± 0.34). The specimens in which the isopropyl alcohol was used, had the highest bond strength results for the sealers, comparing with ethanol (p = 0.005) and EndoVac (p = 0.002). In the canals that ethanol was used, no alteration of the sealer was noticed. The use of paper points, EndoVac and isopropyl alcohol and filling with AH Plus revealed the highest BS values comparing with the other sealers. It was concluded that the infiltration that occurred with AH Plus was similar with the other sealers. AH Plus showed the highest BS. In the cervical third there was preponderance of cohesive failures, and in the other thirds the mixed type of failure.

Dentre as diversas “novas formas de produção” que as empresas construtoras do subsetor edificações têm lançado mão, aparece fortemente o emprego de novas tecnologias, como alternativa para melhorarem seu desempenho e se diferenciarem no mercado. No entanto, entende-se que a melhoria da qualidade do processo de produção, com a introdução de novas tecnologias, deve passar, necessariamente, pela melhor capacitação da mão-de-obra, o que pode ser obtida através de um adequado processo de treinamento. Partindo-se deste pressuposto, buscou-se compreender como vem se dando a participação da mão-de-obra de produção na evolução dos métodos construtivos, particularmente para a produção de vedações verticais. Para isto, realizou-se uma revisão bibliográfica enfocando a evolução desses métodos, desde o Brasil colônia até os dias atuais e, além disso, levantou-se as características da mão-de-obra de produção, tanto na indústria da construção civil como na seriada. Como resultado desse levantamento, verificou-se que o treinamento tem sido um fator fundamental para a evolução dos processos de trabalho, sobretudo na indústria seriada. A partir desta constatação, buscou-se identificar como o treinamento tem sido encarado pelas empresas envolvidas com a produção de edifícios. Esta etapa do trabalho foi realizada através de uma pesquisa de campo em que se analisou os treinamentos oferecidos por empresas construtoras, subempreiteiras e fabricantes de materiais e componentes, quando da implantação de novas tecnologias, em particular a alvenaria racionalizada e as divisórias de gesso acartonado. Finalmente, reunindo-se os dados da bibliografia estudada com os da pesquisa de campo, foi possível confirmar o pressuposto inicialmente apresentado e, procurando contribuir com o meio técnico, assumiu-se como objetivo principal do trabalho a proposição de diretrizes que possam balizar o treinamento da mão-de-obra de produção. Acredita-se que a implantação das diretrizes aqui propostas contribuirá para a evolução da capacitação dos operários, com um conseqüente aumento da melhoria do processo de produção dentro das empresas do setor, acarretando num aumento de sua competitividade. / Among the different "new forms of production" used by constructors in the building sub-sector, the employment of new technologies stands out as an alternative to improve their performance and to make a difference in the market. Nevertheless, it is understood that improvements in the production process quality, with the introduction of new technologies, must necessarily undergo better manpower qualification, which may be achieved by an adequate training process. From this presumption, the aim was to understand how the participation of production manpower is affecting the evolution of constructive methods, particularly for the production of vertical sealing. For this, a bibliographical revision was performed, focusing on the evolution of these methods, since the Brazilian colonial times up to the present; also, the characteristics of production manpower were researched both in the civil construction industry and in the manufacturing industry. As a result of this research, it was verified that training has been a fundamental factor for the evolution of manpower processes, specially in the manufacturing industry. This been seen, the quest was to verify how training has been faced by the companies involved in the production of buildings. This work was performed through a field research in which the training offered by contractors, subcontractors, as well as by materials and components manufacturers was analyzed, when new technologies were implemented, particularly rationalized masonry and gypsum wallboard partitions. Finally, gathering the studied bibliographic data, it was possible to confirm the presumption initially presented and, seeking to contribute to the technical environment, the proposition of directives that may orient production manpower training was established as the main aim of the work. It is believed that the implementation of the directives here proposed will contribute to enhance manpower training, with a consequent increase in the improvement of the production process for the companies in the sector, resulting in higher competitiveness.

Orientador: Francisco Jose de Souza Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-02T02:43:04Z (GMT). No. of bitstreams: 1 Velasco_JoaoOdilo_D.pdf: 2978488 bytes, checksum: f6f430cc9935683be2970d24cd33c8c6 (MD5) Previous issue date: 2002 / Resumo: Este trabalho teve por objetivo estudar in vitro a qualidade do selamento apical de obturações endodônticas realizadas em 72 dentes humanos com canais radiculares preparados, utilizando-se a técnica de instrumentação coroa-ápice com auxílio de instrumentos rotatórios e instrumentação manual do terço apical, usando hipoclorito de sódio 5,25% ou gluconato de clorexidina 2% gel como substâncias químicas irrigadoras e irrigação final com diferentes soluções ou combinações de diferentes soluções. Os canais radiculares foram obturados pela técnica da compressão hidráulica vertical e cimento Endomethasone. Para a avaliação da microinfiltração apical, os dentes foram impermeabilizados com esmalte para unha, com exceção de 2mm apicais, mergulhados em tinta Nankin, submetidos a vácuo e deixados no corante por um período experimental de 7 dias a 37° C. Após a remoção da película de esmalte, as raízes foram diafanizadas e, a seguir, analisadas sob lupa estereoscópica. A qualidade do selamento apical foi avaliada em relação à penetração ou não do corante entre as paredes do canal e a obturação ou entre os componentes da obturação. Os resultados obtidos foram analisados estatisticamente segundo o teste de hipótese de Student a um nível de significância p=0,05,não tendo sido observada diferença estatística na qualidade do selamento apical em dentes com canais radiculares preparados com as diferentes soluções irrigadoras analisadas / Abstract: The objective of this study was to determine in vitro the apical sealing ability in endodontical/y treated human teeth. Seventy-two root canais were prepared by crown-down technique using 5,25% NaOCI or 2% chlorhexidine gluconate gel as an endodontic irrigant between each instrument and a final flushing of various solutions or combinations of solutions. These canais were then filled by an single gutta-percha cone and Endomethazone sealer. The teeth were coated with nail varnish layers, except the apical 2 mm, then immersed in black India ink under vacuum conditions during 10 minutes and stored for 7 days at 37° C. The specimens were rinsed under tap water and the vamish removed. The roots were subsequently cleared and examined at 15 magnification with a stereomicroscope. The apical sealing ability was determined by the penetration of ink beyond the end of the preparation. Data were analyzed statistically using the Student's test. The levei of significance was set at p = 0,05. The results obtained indicated that there is no difference in the apical sealing quality of endodontically treated teeth prepared with differents irrigants / Doutorado / Endodontia / Doutor em Clínica Odontológica

Stora Enso Kvarnsveden är ett pappersbruk lokaliserat vid Dalälven i Kvarnsveden. Bruket har för tillfället två producerande maskiner och detta arbete behandlar en av dem, vilken är PM12. På PM12 har man problem med oljeläckage i maskinens torkparti. Läckagen uppstår genom de lagerhus som finns för att bära upp torkpartiets valsar. I detta arbete har man undersökt vad läckagen beror på med fokus på dess lagertätningar. Syftet och målet med detta arbete har varit att utreda varför läckagen uppstår samt att generera koncept för att minska eller helt eliminera läckagen. Arbetet har innefattat diverse mätningar och utredningar för att komma till rätta med problemet. En litteraturstudie har genomförts för att identifiera felorsaker samt lösningar. Koncept har genererats utifrån studien samt de mätningar som utförts. Man har inte under arbetets gång helt kommit fram till vad läckagen beror på men man har kommit en bra bit på vägen. Förslag till fortsatt arbete har getts där det rekommenderas mer specifikt vilka typer av mätningar som bör genomföras samt de koncept man som bör bygga vidare på. / Stora Enso Kvarnsveden is a paper mill located at Dalälven in Kvarnsveden. The utility currently has two producing machines, and this study deals with one of them, which is PM12. At PM12 there is a problem with oil leaks in the machine's drying section. Leakage occurs through the bearing houses who are there to support the dryer's rollers. In this study, it has been investigated what the leakage is due to focusing on its bearing seals. The purpose of this study has been to investigate why leakage occurs and to generate concepts to reduce or eliminate leaks. The study has included various measurements and investigations to address the problem. A literature study has been conducted to identify causes and solutions. Concepts have been generated from the literature study as well as the measurements that have been taken. After this study it´s not fully realized why the leakage occurs, but it had come a long bit on the way. Proposals for continued work have been given, where it is recommended more specifically what kind of measurements that should be done and the concepts that should be further developed.

This work investigated the wear mechanisms of turbocharger components in heavy duty diesel engines. By understanding the wear mechanisms that are occurring in turbochargers the life time of the turbocharger components can be improved. For better understanding, as to why the components are worn out, an analysis of several turbocharger components and tribological tests were carried out.   The contact surfaces between turbocharger and sealing rings were analysed. Surfaces are analysed by several methods, including chemical composition of the surface. Influence of different parameters such as contact pressure, sliding velocity, temperature, and distance on friction and wear behaviour are established by performing tribological tests. Pin on disc sliding wear tests were carried out at both room temperature and at high temperature of 300˚C. The pin and the disc, that were used during the tribological tests, were made of the same materials that are used in turbocharger components.   Analysis of pins and discs from tribo-tests and turbocharger components (turbine sealing rings and shafts) show abrasive and adhesive wear on the worn surfaces of the components, from both the tribological tests and the turbochargers respectively. An increase of the temperature resulted in a reduced friction due to the formation of oxide layers on the sliding surfaces of pins and discs. In the turbocharger, traces of lubricant between the sliding surfaces was found, in addition to plastic deformations on the worn surfaces of the shafts and adhesive and abrasive wear on both worn surfaces that were in contact with each other. On the other hand, on the worn surfaces of the turbine sealing rings some cracks were observed that were perpendicular to the sliding direction, which indicates presence of a fatigue process. The presence of fatigue cracks is probably due to the way the trucks were operated, the increase and decrease of temperature and pressure in the turbocharger is probably the cause of these cracks.   To minimize the wear mechanisms that occurs in turbocharger components such as sealing rings and shafts, there are some parameters such as contact pressure between the sliding surfaces of the components that can be minimized. By minimizing the contact pressure between the sliding surfaces, the lifetime of turbocharger can be improved. A better surface finishing and geometry of the contacting surfaces can also improve the sealing rings and shafts lifetime. To minimize the relaxation of turbine sealing rings, materials that can better keep the mechanical properties of the sealing rings at high temperatures must be used.

In-situ x-ray photoemission (XPS) and ex-situ FTIR studies of nanoporous organosilicate glass (OSG) films point to the separate roles of radicals vs. VUV photons in the carbon abstraction. The studies indicate that reaction with O2 in presence of VUV photons (~123 nm) result in significant carbon abstraction within the bulk and that the kinetics of this process is diffusion-limited. In contrast, OSG exposed to atomic O (no VUV) results in Si-C bond scission and Si-O bond formation, but this process is self-limiting after formation of ~1 nm thick SiO2 surface layer that inhibits further diffusion. Therefore, the diffusion-dominated kinetics of carbon abstraction observed for OSG exposed to O2 plasma is definitively attributed to the diffusion of O2 down OSG nanopores, reacting at photo-activated sites, rather than to the diffusion of atomic O. Pretreatment of OSG by 900 eV Ar+ ion bombardment also results in formation of 1 nm thick SiO2-like surface overlayer that inhibits O2 diffusion, inhibiting VUV+O2 and O2 plasma-induced reactions, and that the effectiveness of this treatment increases with ion kinetic energy. On the contrary, organosilicate glass (OSG) films with backbone carbon (-Si-R-Si-) exhibit significantly enhanced resistance to carbon loss upon exposure to O2 plasma, radicals and VUV+O2 compared to films with terminal methyl groups (Si-CH3). Films incorporating backbone carbon chains (-Si-R-Si-) were deposited from 1,2 bis (triethoxysilyl) ethane (BTESE) precursor by ebeam or plasma cross-linking. The radical effects on BTESE film indicates negligible carbon loss or Si oxidation, combined with C-O bond formation, under conditions where OSG films with terminal methyl groups exhibit > 80% carbon loss within the surface region of the film. C-O bond formation is never observed for terminal CH3 groups. Further, backbone carbon (-Si-R-Si-) films exposed to VUV+O2 exhibit self-limiting, minimal net carbon loss. This indicates that plasma-induced Si-C bond rupture still occurs in the linking unit, but with a low probability of simultaneous rupture of both Si-C bonds required for abstraction of an in-line methylene bridging group. The data thus demonstrate that OSG films containing backbone carbon groups exhibit greatly reduced rates of carbon loss in the presence of O2 plasma, radicals or VUV+O2 compared to films with terminal carbon groups due to fundamentally different patterns of Si-C bond scission. The results demonstrate the potential of backbone carbon low-k films to resist plasma induced damage.

This master thesis focuses on the issue of tightness evaluation of gasketed tubesheet in U tube exchangers, which meets strength requirements of ČSN EN 13 445-3 and ČSN EN 1591-1 standards. It deals with the forces acting on the gasket when measuring the effects acting on the entire heat exchanger. A separate part is devoted to the calculation of the heat profile in the heat exchanger and verification of the strength of the heat exchanger. The final part introduces model of a heat exchanger, on which a possible approach to solving the tightness of the tubesheet in heat exchangers is presented. In thesis temperature field evaluation was conducted, the results of which were used in stress strain analysis, in order to obtain gasket contact pressure. Extreme gasket contact pressures were used to estimate leak rate limits.

This project addresses the issue of pressing sealing shaft ring in the flange. Effect of flange material changes to static leakage between the flange and the sealing ring, the surviving process parameters. An optimal use of process fluids to eliminate leaks.

Nowadays sealing systems are commonly designed by means of hydrodynamic and elastohydrodynamic theories. Although the analytical as well as the computational approaches have improved in meaning full manner since the last decades: For small sealing gaps, in the order of micrometers and below, a discrepancy between experimental investigated and theoretically predicted leakage flows occur. As a cause for the discrepancy a breakdown of the no slip boundary condition is suspected. Since in small sealing gaps the continuum hypothesis is violated and molecular effects have to be considered. One fundamental quantity to take molecular affects into account is the slip length. Within this paper a new measurement apparatus to evaluate the slip length for hydraulic applications is presented. The adjustable gaps between two planar surfaces are in the order of magnitude of 1 μm. In a first step the slip length for the system steel-oil –steel is investigated at three different temperatures: 18°C, 22°C and 25°C. The measured slip lengths are in the order of magnitude of ~100 nm.