O objetivo deste estudo foi avaliar in situ o efeito da saliva, associada ou não ao flúor, sobre a estrutura dentária do esmalte que recebeu profilaxia prévia com jato de bicarbonato de sódio. Foram utilizados 40 blocos de esmalte de dente bovino de 4x4 mm, nos quais foi aplicado o jato de bicarbonato de sódio por 10s, simulando a realização de uma profilaxia profissional. Após essa etapa, os blocos foram divididos em dois grupos (GI e GII) e montados em dispositivos intra-bucais, os quais foram utilizados por 10 voluntários, durante dois períodos experimentais cruzados e cegos de quatro horas. Os blocos do GI foram expostos diretamente à saliva in situ, enquanto os do GII, foram expostos à saliva associada ao flúor sob forma de bochecho com solução de NaF a 0,2%, durante o minuto inicial. As possíveis alterações ocorridas na superfície do esmalte após as etapas do experimento foram avaliadas através de testes de microdureza superficial (Knoop-25g/5s) e de desgaste. Os dados de microdureza superficial foram analisados pela Análise de Variância a dois Critérios (ANOVA) e teste de Tukey (p<0,05) e os dados de desgaste pelo teste T pareado, para a diferença entre perfil inicial e final (p<0,05). Não foi encontrada diferença estatisticamente significante entre GI e GII, para as variáveis dureza e desgaste. A média de desgaste após profilaxia não apresentou diferença da média após a etapa in situ. No entanto, a média de microdureza no início, após a profilaxia e após a etapa in situ foi respectivamente: GI (340±16,6a; 329±35,7b; 354±37,8a) e GII (338±15,6a; 312 ±46,3b; 340±21,8a). Com base nos resultados encontrados pôde-se concluir que a saliva apresentou efeito semelhante a saliva associada ao bochecho fluoretado e após 4 horas de remineralização in situ não houve recuperação em altura de parte da estrutura dentária perdida devido à aplicação do jato de bicarbonato de sódio sobre o esmalte hígido. / The aim of this in situ study was to evaluate the effect of the saliva, associated or not to fluoride, on the superficial enamel structure in which a sodium bicarbonate jet was applied. Forty bovine enamel specimens (4x4 mm) were subjected to sodium bicarbonate jet for 10 seconds to simulate a prophylaxis procedure. The specimens were then divided the in two groups (GI and GII) and were mounted in a intra-oral device which were used by 10 volunteers for two cross-over, blind experimental periods of 4 hours. The specimens of GI were directly exposed to saliva in situ, while those of GII were exposed to saliva associated to fluoride by mouthrinsing 0,2%NaF solution on the first minute of the experiment. The changes on the enamel surface were analyzed by superficial microhardness test (Knoop, 25g/5s) and perfilometry (wear). Two-way ANOVA and Tukey test (p<0,05) were used for microhardness data. The wear was analyzed by T pare test for the initial and final profile difference (p<0,05). There were no statistically difference between GI and GII, in respect to microhardness and wear. The mean enamel wear after sodium bicarbonate jet application was not significantly different from the enamel mean wear after the in situ phase. However the microhardness mean values at baseline, after sodium bicarbonate jet application and after in situ phase were respectively: GI (340±16.6a; 329±35.7b; 354±37.8a) e GII (338±15.6a; 312 ±46.3b; 340±21.8a). In according to the obtained results it was concluded that saliva presented the same effect on enamel recovery when compared to saliva associated to fluoride. After 4 hours of in situ remineralization, it was not observed the height recovery of the enamel, lost by wear due to the use of a sodium bicarbonate jet application.

As superligas à base de cobalto são bem conhecidas por sua excelente resistência ao desgaste. Muitas pesquisas reportadas na literatura abordam o comportamento do desgaste destas ligas, seja no desgaste por deslizamento, erosivo ou abrasivo. Não obstante, o desgaste microabrasivo destas ligas não tem sido muito investigado, apesar dos danos causados por este tipo de solicitação. O comportamento do desgaste microabrasivo de três superligas à base de cobalto: a) 48% Co, 29 %Cr, 19 % Fe; b) uma liga com composição química próxima à da liga comercial Tribaloy T400 (Co 56 %, Cr 8.5%, Mo 29% Si 3.3 %) e c) uma liga com composição próxima à da liga comercial Stellite 6 (Co 64%, Cr 24 %, W 4.2 %, C 2,3%) foram investigadas. Os ensaios de microabrasão foram conduzidos com três abrasivos SiO2, Al2O3, e SiC em suspensão em água destilada, com concentração de 0,1 g/cm3. A carga aplicada foi de 0,3 N, a velocidade angular 20 rpm e a distância total de deslizamento, 48 metros. A análise das superfícies desgastadas por microscopia óptica, eletrônica de varredura e por perfilometria de contato mostraram que o tamanho, forma e dureza dos abrasivos podem influenciar significativamente os coeficientes de desgaste. Os ensaios conduzidos com partículas abrasivas de SiC e Al2O3 apresentaram maiores coeficientes de desgaste que os conduzidos com partículas de SiO2. A Liga Co-Cr-Fe mostrou os maiores coeficientes de desgaste quando comparada com as demais ligas, devido à baixa fração volumétrica de partículas de segunda fase, duras, precipitadas em sua microestrutura. Durante os ensaios, as três ligas, ensaiadas com os três diferentes abrasivos, apresentaram coeficientes de desgaste crescentes com o aumento da dureza do abrasivo; observou-se uma variação linear dos coeficientes de desgaste com a razão entre a dureza do abrasivo (Ha) e a dureza composta da liga (Hs), com R2 = 0.74. O micromecanismo dominante em todos os ensaios foi o desgaste abrasivo a dois corpos (grooving wear). A liga com composição próxima à da liga comercial Tribaloy T400, contendo fases de Laves dispersas em sua microestrutura, apresentou uma transição de micromecanismo de desgaste dúctil para frágil, quando submetida a ensaios com partículas abrasivas de Al2O3. Assim sendo, o volume de material removido nesta liga foi ligeiramente maior que o observado no ensaio com partículas de SiC. Na liga contendo baixa fração volumétrica de partículas de segunda fase, com matriz constituída por Co (CFC), observou-se uma camada subsuperficial nanocristalina de aproximadamente 1 µm de espessura, severamente deformada, imediatamente abaixo da superfície desgastada. Concluiu-se que o desgaste microabrasivo induziu a recristalização a frio do material encruado, com formação de grãos equiaxiais de dimensões nanométricas. / Cobalt alloys are well known for their excellent wear resistance. Many investigations are reported in literature related to the behavior of erosive, abrasive or sliding wear of these alloys. Nevertheless, the micro-abrasive wear of these alloys has not been thoroughly investigated, despite the damage caused by this type of wear. The microabrasive wear behavior of three cobalt alloys: a) 48 wt.% Co, 29 wt.% Cr, 19 wt.% Fe; b) an alloy with chemical composition close to Tribaloy T400 (56 wt.% Co, 8.5 wt.% Cr, 29% wt. Mo, 3.3 wt. %Si) and c) an alloy with chemical composition close to Stellite 6 (64wt.% Co 24 wt.% Cr, 4.2 wt.% W, 2,3 wt.% C were investigated. The tests were carried out using three 0,1 g/cm3 slurries composed by SiO2, Al2O3, and SiC particles, in suspension in distilled water. The applied load was 0.3 N, the rotational speed 20 rpm and the total sliding distance 48 m. Analysis of the worn surfaces of the tested alloys by Optical Microscopy, Scanning Electron Microscopy and Contact Stylus Profilometry showed that abrasive size, shape and hardness could significantly influence the wear coefficients. The tests carried out with SiC and Al2O3 slurries resulted in greater wear rates than those carried out in SiO2 slurry. Stellite 250, showed the greatest wear coefficient, compared to the two other experimental alloys, due to a very low volume fraction of hard second phase particles in the microstructure. Wear coefficients decreased with increasing abrasive particles hardness. An approximate linear correlation with the ratio between the hardness of the abrasives (Ha) and the compound hardness of the alloys (Ha) with a correlation factor R2= 0.74. The dominant wear micromechanism observed in all tests was two-body abrasion (grooving wear). The modified T400 alloy, containing Laves phase showed a transition from ductile to brittle wear mechanisms when testing with alumina slurries. The worn volume was slightly greater than the one observed with SiC. A severely deformed nanocrystalline layer was identified, immediately below the worn surface. It was concluded that cold recrystallization of the work-hardened material occurred, with the formation of nano sized equiaxed grains.

Orientador: Jose Pedrazzoli Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-03T17:07:13Z (GMT). No. of bitstreams: 1 CasonatoJunior_Homero_M.pdf: 3469755 bytes, checksum: 5fecd41245393d9b43bda2618e5d8183 (MD5) Previous issue date: 2003 / Resumo: O estudo teve como objetivo avaliar a prevalência de manifestações bucais como periodontite, gengivite, erosão, abrasão, atrição e cárie dental, e relaciona-las com a doença de refluxo gastroesofágica. Para isso foram avaliados indivíduos que efetivamente apresentavam esofagite de refluxo (grupo I) e indivíduos que apresentavam dispepsia sem esofagite de refluxo (grupo II). Utilizando-se de um estudo duplo cego a coleta de dados ocorreu em um primeiro instante, através de exame endoscópico, avaliando-se a condição esofágica de 56 indivíduos (26 homens, 30 mulheres), com idade média de 40 anos (20-69 anos) e num segundo momento pela avaliação da saúde bucal através de exames clínico e radiográfico, porém sem o conhecimento prévio, pelo examinador, da condição esofágica. Também foram registrados através de questionário, hábitos medicamentosos, alimentares, de higiene bucal e hábitos bucais nocivos. Dentre os indivíduos do grupo I, todos apresentaram algum nível de atrição dental, 93,33% apresentaram abrasão dental, 56,67% apresentam erosão dental, 66,67% apresentaram cárie dental, 60% apresentaram periodontite e apenas um indivíduo não apresentou gengivite. Já os indivíduos do grupo II, todos apresentaram atrição dental, 80,77% apresentam abrasão dental, 46,15% apresentam erosão dental, 88,46% apresentaram cárie dental, 73,08% apresentaram periodontite e a totalidade dos indivíduos apresentou gengivite. Foram examinados 1437 dentes; Destes, 736 do grupo I, dos quais 17% apresentaram periodontite, 39% gengivite, 35,5% abrasão, 44% atrição, 23,5% erosão e 9% de dentes com cárie. No grupo 11 foram examinados 701 dentes, dos quais 18% apresentaram periodontite, 44,5% gengivite, 20% abrasão, 36% atrição, 15,5% erosão e 12,5% com cárie. Concluiu-se que a presença de esofagite de refluxo não interferiu na prevalência de gengivite, periodontite, atrição e erosão, embora a prevalência de abrasão foi maior entre os indivíduos com esofagite de refluxo / Abstract: The aim of this study was to evaluate the prevalence of oral manifestations, such as periodontites, gingivitis, abrasion, attrition, erosion and dental decay relating them to the gastroesofageal reflux disease. For this purpose individuals that indeed presented reflux esophagitis (group I) and individuals that presented dyspepsia without reflux esophagitis (group II) were evaluated. Through a blind double study, the collection of data was carried out in a first instant through endoscopies, evaluating the esophageal condition of 56 individuals (26 male, 30 female), average age 40 (range 20-69 years) and in a second moment through the evaluation of the oral health through clinical and radiographic exams, however, without the examiner's previous knowledge of the individuals' esophageal condition. They were also registered through a questionnaire that took into consideration medication and alimentary habits, oral hygiene as well as oral habits that could be considered noxious. All individuals in group I presented some level of dental attrition, 93,33% with dental abrasion, 56,67% with dental erosion, 66,67% with decay, 60% with periodontites and there was only one individual who did not present gingivitis. In group II all of them presented attrition and gingivitis, 80,77% with dental abrasion, 46,15% with dental erosion, 88,46% with decay, 73,08% with periodontites. All of the individuals studied were responsible for 1437 examined teeth; 736 out of the 1437 teeth in group I presented the following problems: 17% with periodontites, 39% gingivitis, 35,5% abrasion, 44% attrition, 23,5% with erosion and 9% of the teeth with decay. In group II, 701 teeth were examined and they presented 18% with periodontites, 45% gingivitis, 20% abrasion, 36% attrition, 15,5% with erosion and 12,5% with decay. It was conc1uded 1hat the presence of reflux esophagitis did not interfere in the prevalence of gingivitis, periodontites, erosion, decay and attrition, despite the fact that the prevalence of abrasion was higher in individuals with reflux esophagitis / Mestrado / Ciencias Biomedicas / Mestre em Ciências Médicas

Post surgical adhesions (PSAs) are an inevitable outcome of surgery and their presence leads to pathogeneses and significant economic impact. The studies within this thesis utilised standard and reproducible abrasion models, in rabbits, pigs and rats, to investigate the formation and maturation of PSAs with strict quantitative analyses. These studies have shown that the development of PSAs is a series of complex, multi-factorial processes. PSA development can be classified into two stages: (i) PSA modelling occurring up to/including 16 hours post injury characterised by the inflammatory response and fibrin deposition and maturation; and (ii) PSA remodelling occurring from 16 hours onwards and characterised by tissue repair, collagen deposition and maturation and chemical mediation by TGF-P. Treatment with VivostatTM System Derived (novel) Fibrin Sealant significantly reduced the formation of PSAs with mean PSA reduction of 80% for the rabbit uterine horn abrasion model, from 3 separate studies; 83% for the pig stomach/colon/caecum abrasion model, from 2 separate studies; 80% for the rat caecum abrasion model. This is significantly better than other fibrin sealants investigated in this thesis. PSA prevention with novel fibrin sealant demonstrated a similar pattern to PSA development, with two stages of development evident: (i) tissue generation modelling occurring up to/including 16 hours post injury characterised by the inflammatory response and fibrin deposition and maturation; and (ii) tissue generation remodelling occurring from 16 hours onwards and characterised by tissue repair, collagen deposition and maturation and chemical mediation by TGF-P. However the extent and subsequent time taken for these changes to occur was significantly reduced. The prevention of PSAs and alterations of wound healing by novel fibrin sealant is most probably due to the sealant acting as a haemostat, as well as a physical barrier. Thus preventing fibrinous and subsequent fibrous PSA formation.

Dans les industries automobile et aéronautique, les opérations de finition des pièces métalliques sont souvent réalisées avec des bandes abrasives ; on parle alors de « toilage ». Lors des opérations de toilage à sec des aciers, les conditions à l’interface entre l’outil abrasif et la pièce métallique usinée sont très sévères en termes de pression et de température. Un transfert métallique, communément appelé « chargement métallique » est observé à la surface des grains abrasifs en céramique de la bande abrasive, entrainant une chute de ses performances de coupe. L’objectif de ce travail est de comprendre ce phénomène de chargement métallique et notamment de mettre en évidence les paramètres l’influençant. L’effet de la nature des grains, de la nature des aciers ou encore de la présence de charges actives dans la bande abrasive ont donc été étudié. Une étude a donc été réalisée à différentes échelles : à l’échelle globale du contact bande abrasive / métal sur un dispositif industriel de toilage, puis à l’échelle plus locale du contact entre la céramique (du grain abrasif) et du métal, grâce à un dispositif tribologique adapté. Des caractérisations physico-chimiques par XPS (X-Ray Photoelectron Spectroscopy) et TEM-EDX (Transmission Electron Microscopy couplée avec la spectroscopie Energy Dispersive X-ray) des bandes abrasives ont également été réalisées. L’influence des charges actives, produits fluorés ajoutés à la résine de la bande abrasive, sur l’adhésion du métal sur le grain céramique a ainsi été mise en évidence, notamment dans le cas de l’acier inoxydable 304 où le chargement métallique a été fortement limité. Les mécanismes d’action de ces charges actives sont ensuite discutés. / In automotive and aeronautic industries, grinding operations can sometimes be done with abrasive belts. During dry metal grinding, conditions at the interface between the abrasive tool and the metal workpiece are very hard in terms of pressure and temperature. Metal transfer, known as “metal capping”, is observed at the surface of the abrasive ceramic grain inducing a drop in the cutting efficiency. The objective of this work is to understand this metal capping phenomenon and to highlight the parameters which have an influence on it. The effects of abrasive grain nature, metal nature or active filler presence in the abrasive belt are then studied. A study has been done at different scales: at the global scale of the abrasive belt / metal contact thanks to an industrial grinding test, and then at the more local scale of the contact between ceramic (from the abrasive grain) and metal, thanks to a suitable tribological device. Physicochemical characterizations by XPS (X-Ray Photoelectron Spectroscopy) and TEM-EDX (Transmission Electron Microscopy coupled with Energy Dispersive X-ray spectroscopy) were carried out on worn abrasive belts. The influence of the active fillers – fluorinated products added in the resin of the abrasive belt – on metal adhesion on the ceramic grain was then observed, especially in the case of the 304 stainless steel grinding where metal capping was significantly reduced. Action mechanisms of these active fillers were finally discussed.

Orientador: Enilson Antonio Sallum / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-14T12:01:49Z (GMT). No. of bitstreams: 1 Santamaria_MauroPedrine_D.pdf: 1906873 bytes, checksum: 996991755e8909f6c85dd127ec284d0f (MD5) Previous issue date: 2009 / Resumo: Recessões gengivais estão freqüentemente associadas às lesões cervicais não-cariosas. O tratamento dessa lesão combinada é um desafio. Trabalhos recentes têm apresentado resultados de tratamento conjunto de cirurgia periodontal e dentística restauradora para tratamento da lesão combinada. Porém nenhum trabalho demonstrou resultados de longo prazo desse tipo de abordagem, além de variações desse tratamento e dos fatores anatômicos locais que poderiam influenciar na resultado dessas terapias. Portanto, os objetivos do presente estudo foram: 1. Apresentar os resultados após 2 anos de tratamento de recessões gengivais associadas à lesões cervicais tratadas com retalho posicionado coronariamente (RPC) sozinho ou associado à restauração de ionômero de vidro modificado por resina (CIV). 2. Avaliar os resultados, após 6 meses de tratamento do enxerto de tecido conjuntivo (ETC) associado ou não à restauração de CIV para tratamento da lesão combinada. 3. Avaliar a possível influência das características anatômicas locais no recobrimento das lesões combinadas tratadas pelas técnicas do retalho posicionado coronariamente e pelo enxerto de tecido conjuntivo. Para o primeiro objetivo, foi realizado um estudo clínico controlado e randomizado que foram incluídos 16 indivíduos apresentando duas recessões gengivais bilaterais associadas à lesões cervicais em caninos ou pré-molares superiores. Os defeitos foram tratados com RPC sozinho ou associado à restauração de CIV. Os resultados não demonstraram diferença significante entre os grupos após 2 anos com relação à redução da recessão gengival, ganho no nível clínico de inserção e sangramento à sondagem. Para o segundo objetivo, foi realizado um estudo clinico controlado e randomizado que foram incluídos 40 indivíduos apresentando uma recessão gengival associada à lesão cervical em caninos ou pré-molares superiores. Os defeitos foram tratados com ETC sozinho ou associado à restauração de CIV. Os resultados não demonstraram diferença estatisticamente significante entre os grupos após 6 meses com relação à redução da recessão gengival, ganho no nível clínico de inserção, ganho de tecido queratinizado e sangramento à sondagem. No entanto, o grupo que recebeu ETC e a restauração de CIV foi estatisticamente melhor na redução da hipersensibilidade dentinária. Para o terceiro objetivo, as características anatômicas locais dos indivíduos dos dois estudos clínicos prévios foram medidas e analisadas através de regressão linear multipla. Os resultados demonstraram correlação estatisticamente significante entre a profundidade da lesão cervical não-cariosa e o a redução na recessão gengival quando RPC foi utilizado de forma isolada. A altura da lesão combinada também apresentou correlação estatisticamente significante com a redução da recessão gengival para ambos os estudos. Além disso, a deiscência óssea apresentou correlação estatisticamente significante quando ETC foi utilizado. Dentro dos limites desse estudo, pode-se concluir que a restauração de ionômero de vidro modificado por resina parece não interferir no recobrimento da lesão combinada após 2 anos de avaliação, quando o retalho posicionado coronariamente foi utilizado e após 6 meses quando o enxerto de tecido conjuntivo foi utilizado. A profundidade da lesão cervical pode ter alguma influência quando RPC é utilizado e a deiscência óssea parece não interferir negativamente no recobrimento quando ETC foi utilizado. / Abstract: Gingival recessions are frequently associated with non-carious cervical lesion. Previous studies have shown results from a combined treatment (periodontal surgery plus restoration of the cervical lesion) to deal with the association of these two lesions. However, there is lack of information regarding the long term evaluation of the combined treatment. Moreover, no additional information regarding other surgical techniques and the influence of the local anatomical characteristics have not been evaluated. Thus, the objectives of this study were: 1. Evaluate the 2-year-follow-up outcome of the treatment of gingival recession associated with non-carious cervical lesions by coronally advanced flap alone (CAF), or in combination with a resin-modified glass ionomer restoration 2. Evaluate the 6-month-follow-up outcome of the treatment of gingival recession associated with cervical lesion by connective tissue graft alone (CTG), or in combination with a resin-modified glass ionomer restoration, and 3. Evaluate the possible influence of local anatomy on the amount of soft tissue coverage achieved and on the clinical attachment gain by the use of CAF and CTG, alone or in combination with resin-modified glass ionomer restoration to treat the combined defect. For the first objective, 16 patients with bilateral Miller Class I buccal gingival recessions, associated with non-carious cervical lesions were selected. The defects received either CAF alone or CAF plus a resin-modified glass ionomer restoration. The results showed that both groups showed statistically significant soft tissue coverage. The differences between groups were not statistically significant in reduction of gingival recession, gain in the clinical attachment level, and bleeding on probing after 2 years. For the second objective, 40 patients with Miller Class I buccal gingival recessions, associated with non-carious cervical lesions were enrolled. The defects were randomly assigned to receive either CTG alone or CTG plus a resin-modified glass ionomer restoration. The results showed that both groups showed statistically significant soft tissue coverage. The differences between groups were not statistically significant in gingival recession, gain in the clinical attachment level, and bleeding on probing, after 6 months. However, the group CTG plus the restoration showed statistically significant reduction in dentin sensitivity when compared to CTG alone. For the third objective, the local anatomical characteristics from the patients enrolled in the 2 previous studies were correlated with the reduction of the gingival recession and the gain in the clinical attachment level using Stepwise Multivariate Linear Regression. The results showed that the cervical lesion depth was significantly correlated with reduction in gingival recession, when considering data from the CAF group. The cervical lesion height was statistically correlated with the reduction in gingival recession when the two groups were analyzed. Additionally, the bone level was statistically correlated with reduction in gingival recession when evaluating the CTG group. Within the limits of the present study it can be concluded that the presence of the resin-modified glass ionomer restoration may not interfere with the amount of coverage achieved either by CAF after 2 years or CTG after 6 months. The cervical lesion depth may have some influence on the final coverage achieved when CAF is applied and the bone level may not play any role when CTG is applied. / Doutorado / Periodontia / Doutor em Clínica Odontológica

O presente trabalho apresenta a análise da resistência ao desgaste abrasivo de um revestimento duro e do aço SAE 5160. O revestimento foi obtido pela deposição de uma liga ferrosa através de processo de soldagem \"TIG\" sobre um aço ABNT 1020. Aliga foi desenvolvida com a utilização de CR e Nb como elementos formadores de carbonetos, proporcionando uma microestrutura constituída, no estado bruto de fusão, de uma rede de carbonetos (Cr, Fe)7C3 interdendríticos e NbC dispersos em uma matriz austenítica. Corpos de prova revestidos foram submetidos a tratamentos térmicos de normalização, têmpera, sub-zero e revenido, visando a obtenção de diferentes microestruturas na matriz, enquanto que o aço SAE 5160 foi temperado e revenido de acordo com o procedimento utilizado na confecção de ferramentas agrícolas com este material. A resistência ao desgaste do revestimento foi superior à do aço SAE 5160 nos dois tipos de ensaios de abrasão realizados, sendo os melhores desempenhos apresentados pelo revestimento temperado no ensaio realizado com equipamento do tipo pino sobre lixa e pelo revestimento temperado e revenido no ensaio do tipo roda de borracha/areia seca. A identificação dos mecanismos de remoção de material predominantes nos ensaios abrasivos foi possibilitada pela observação das superfícies desgastadas dos corpos de prova através de microscopia eletrônica de varredura. / The present work presents an analysis of the abrasive wear resistance of a hardfacing and of the SAE 5160 steel. The hardfacing was obtained by the deposition of a iron based alloy through \"TIG\" welding on a ABNT 1020 steel. This alloy was developed with the use of Cr and Nb as carbide forming elements , resulting in a microstructure formed by a carbide net of M7C3 interdendritic in a austenitic matrix. The hardfacing samples suffered heat treatment of normalizing, hardening, tempering and subzero, viewing the achievement of differents microstructure, while the SAE 5160 steel suffered hardening and tempering according to the production process used in the agricutural tool manufacturing. The wear resistance of the hardfacing overcame the SAE 5160 steel in both types of abrasion wear tests, and the best performances were presented by hardening hardfacing in the pin wear test and by the tempering hardfacing in the rubber wheel/dry sand test. The identification of the material removal mechanisms in the abrasive tests was made by the observation of the worn surfaces of the samples through the scanning eletronic microscopy.

Non-exhaust PM10 is an issue in the urban environment linked to health issues. Emissions of non-exhaust PM10 is relatable to pavement properties. Also of importance is resuspension of road dust stored from surfaces. This depends on the traffic and metrological conditions. Given this, the purpose of the thesis was to give an overview limited to Sweden and the Nordic countries regarding non-exhaust PM10 emissions and road dust. The overview includes how particles are related to human health. Also included is the principle of how particles are emitted from road surface and tyre interaction, both directly and through resuspension of road dust. This thesis also includes an overview of how the use of studded tyres impact on asphalt surfacings and how the properties of the materials used impact on the abrasion wear. This is then linked to the emissions of non-exhaust particles. Further described is how measurements can be done of ambient particles and road dust, followed on two major models for road abrasion wear and non-exhaust PM prediction. Also included is how road operation, e.g. traction sanding and dust binding, influence the particle emissions together with other options to reduce the emissions through, e.g. limiting the use of studded tyres. One special issue discussed in this thesis is the lack of holistic view regarding the environmental problems in the urban environment with focus on particle emissions and road noise emissions, both from the road surface and tyre interaction. Currently the most problematic issue is prioritized and the resulting solution to that specific problem might increase other problems. This thesis shows that much knowledge is available regarding non-exhaust PM10 emissions and road dust, but also that several knowledge gaps exists. Several suggestions on further studies is given together with a brief overview on the continued work forward from this thesis. / Icke-avgasemissioner av PM10 är ett problem i urbana miljöer länkat till flera hälsoaspekter. Dessa emissioner kan relateras till beläggningars egenskaper. Även resuspension av vägdamm från ytor är av betydelse och beror på både trafiken och meterologin. Baserat på detta är syftet med denna avhandling att ge en översikt kring icke-avgas PM10 emissioner och vägdamm, begränsat till Sverige och de övriga nordiska länderna. Denna översikt inkluderar hur partiklar relaterar till människans hälsa. Annat som inkluderas är hur partiklarna emitteras från vägyta-däckinteraktionen, både direkt och genom resuspension av vägdamm. Avhandlingen inkluderar även en översikt kring hur användandet av dubbdäck inverkar på vägbeläggningar och hur dess egenskaper inverkar på nötningsslitage. Detta länkas därefter till partikelemissioner. Vidare beskrivs även hur mätningar kan genomföras av partiklar samt vägdamm vilket följs upp av beskrivningar kring två större modeller kring prediktion av nötningsslitage och prediktion av icke-avgasemissioner. Även hur driftåtgärder inverkar på emissionerna tillsammans med alternativ för att minska emissionerna tas upp. Ett särskilt problem som tas upp i avhandlingen är bristen på helhetssyn beträffande miljöproblem i den urbana miljön med fokus på partikel- och bulleremissioner från vägyta-däckinteraktionen. För närvarande brukar det värsta problemet prioriteras och lösningen till det detta problem kan i sin tur medföra att andra miljöproblem istället förvärras. Denna avhandling visar på att mycket kunskap existerar kring icke-avgasemissioner av PM10 och kring vägdamm, men även att flertalet kunskapsluckor existerar. Flertalet förslag på vidare studier ges tillsammans med en överblick kring det fortsatta arbetet.

This paper is focused on MR dampers and its critical parts in term of damper`s durability, which seems to be a piston-rod seals, and it should find an ideal material combination of seal and MR fluid for increasing the damper`s life. The tests were conducted in modified pin-on-flat configuration, which was supposed to be more suitable for laboratory testing. There was tested and compared a suitable material for seals, like PTFE, NBR, SBR of polyurethanes. The article is also focused on MR fluids and its contribution to seal`s wear. The impact of particle concentration, wear of MR fluid and effect of modification of MR fluid was tested. It showed up, that the best material for seal is H-PU95FDA. The effect of particle concentration is negligible on seal`s wear, while effect of modification and wear of MR fluids are significantly higher.

This thesis covers the state assessment of the selected bank sections of dam reservoirs Vranov and Boskovice. Data used and processed in this thesis were acquired by visiting both sites several times in order to perform measurements and make photographic documentation. Futhermore, data on reservoirs' water levels from 2000-2011 provided by Povodí Moravy s.p. were used. In order to determine bank line regression, the above-mentioned data were processed using the Šlezingr's modification of the method of abrasion terminants determination. Results for dam reservoirs Vranov and Boskovice are then compared with results of dam reservoir Brno, which were produced by the author within the framework of his bachelor thesis using the same method. At the end of the thesis, the author presents several possible forms of stabilization and protection of disrupted banks of dam reservoirs, including their drawings.