Syfte: Syftet med föreliggande studie var att utvärdera om högtranslucent zirkoniumdioxid abraderar mer på naturlig emalj jämfört med traditionell zirkoniumdioxid och fältspatsporslin.Material och metod: Provkroppar till tre materialgrupper av måtten 20mm x 10mm x 5mm togs fram (n=3) och bestod av högtranslucent zirkoniumdioxid som färgades, glansbrändes och polerades (HTZ), traditionell zirkoniumdioxid som polerades (ZIR) och en kontrollgrupp med fältspatsporslin som glansbrändes (FP). Inför abrasionstestet valdes tre premolarer ut som överensstämde med varandra och bäddades in i varsin cylindrisk form med epoxy. Tänderna avlästes med en intraoral scanner före och efter varje abrasionstest (intakt, 3500 och 10500 slitagevarv). Ytstrukturen analyserades och mättes vid tre punkter på varje provkropp och respektive tand med interferometri före och efter varje abrasionstest.Resultat: Analys av tänderna med intraoral scanner visade att den största avverkningen skett vid abrasion mot högtranslucent zirkoniumdioxid följt av traditionell zirkoniumdioxid och slutligen fältspatsporslin, samtliga efter 10500 slitagevarv. Analys av provkropparna med interferometri visade att det material vars ytor påverkats mest av emalj vid abrasion var fältspatsporslin. Den högtranslucenta respektive traditionella zirkoniumdioxiden uppvisade mindre förändringar. Slutsats: Inom ramen för denna studies begränsningar så visar abrasionstesterna att glansbränd och polerad högtranslucent zirkoniumdioxid abraderar mest på emalj jämfört med traditionellt zirkoniumdioxid och fältspatsporslin. Det material vars ytstruktur påverkats mest av emalj var fältspatsporslin.

Yes / Inspired from the low wetting properties of Lotus leaves, the fabrication of dual micro/nano-scale topographies is of interest to many applications. In this research, superhydrophobic surfaces are fabricated by a process chain combining ultrashort pulsed laser texturing of steel inserts and injection moulding to produce textured polypropylene parts. This manufacturing route is very promising and could be economically viable for mass production of polymeric parts with superhydrophobic properties. However, surface damages, such as wear and abrasion phenomena, can be detrimental to the attractive wetting properties of replicated textured surfaces. Therefore, the final product lifespan is investigated by employing mechanical cleaning of textured polypropylene surfaces with multipurpose cloths following the ASTM D3450 standard. Secondly, the surface damage of replication masters after 350 injection moulding cycles with glass-fiber reinforced polypropylene, especially to intensify mould wear, was investigated. In both cases, the degradation of the dual-scale surface textures had a clear impact on surface topography of the replicas and thus on their wetting properties, too. / Europe Union H2020 research and innovation programme.

A major challenge in tire research, is tire wear modeling. There are too many factors affecting tire wear, and part of those factors are difficult to be accurately expressed in physics and math. The objective of this research is to develop a machine learning based rubber sample wear model, and find the correlation between sample wear and tire wear. To develop this model, accurate and diverse wear data is necessary. The Dynamic Friction Tester (DFT) was designed and built for this purpose. This test machine has made it possible to collect accurate rubber sample wear data which has been validated under different conditions. Wear tests under diverse test conditions were conducted, and the test data were used to train machine learned based wear models with different algorithms, such as Neural Networks and Support Vector Machines. With test-proved wear behavior classification as additional input, and feature selection, performance of the trained rubber sample wear model has been further improved. To correlate rubber sample wear and tire wear, a set of correlation functions were developed and proposed. By validating the correlation functions using tire wear test data collected on roads, this research contributes a fast and economical approach to predict tire wear. / Doctor of Philosophy / Tire wear is closely related to the life time of tire, and excessive wear of tire can results in serious accidents. Since 1950s, research have been done to predict tire wear using experiments and empirical relations. These approaches are expensive, time consuming, and highly restricted to certain conditions. The objectives of this research is to develop a statistic based rubber sample wear model, and find the correlation between rubber sample wear and tire wear. To develop the statistic based rubber sample wear model, a test machine, named Dynamic Friction Tester (DFT) was designed and built to collect rubber sample wear data. The final rubber sample wear model is trained by wear data under 600 different test conditions. A set of mathematical equations were proposed to correlate rubber sample wear and tire wear. These equations were validated by actual tire wear data collected from lab and public roads. In combination of the statistic based rubber sample wear model and mathematical relation between rubber sample wear and tire wear, this research contributes a flexible, economical, and fast method to predict tire wear.

The purpose of this research was to investigate and compare the effects of different abrasion treatments on the liquid-fabric interaction of selected nonwoven barrier fabrics. The abrasion treatments included moderate and severe abrasion, flat and flat/flex abrasion, and dry and wet abrasion. The liquid-fabric interactions included wetting/wicking, retention, and penetration through nonwoven fabrics using water/surfactant solution. Results of this study indicated that abrasion treatments increased the wetting/wicking rate of fabrics. The flat/flex abrasion caused a greater increase in the wetting/wicking rate of fabrics than the flat abrasion. Abrasion treatments also increased liquid penetration. The flat abrasion increased liquid penetration more than flat/flex abrasion. On increasing abrasion severity, there was a significant increase in liquid penetration. There was no consistent effect on liquid retention. It was highly influenced by fabric types. Wet abrasion did not differ significantly from dry abrasion in its effects on liquid/fabric interaction. Six nonwoven fabrics used in this study included a hydroentangled cotton fabric with a fluorochemical finish (HCF), a hydroentangled cotton fabric laminated with a microporous film (HCE), a spunbonded polypropylene with microporous film (PSM), a four layer laminated nonwoven including spunbonded polypropylene, microporous film, hydroentangled cotton layer, and spunbonded polypropylene (PECP), a spun-bonded, melt-blown, spun-bonded polypropylene (SMS), and standard Tyvek®. Among the six fabrics, the cotton fabrics with a fluorochemical finish (HCF) and the cotton fabric with a microporous film (HCE) showed an excellent potential as protective material, since they provided high liquid resistance before and after abrasion. However, there was no consistent trend for microporous film fabrics or for cotton containing fabrics to provide a good liquid protection. In general, it was concluded that abrasion significantly decreased liquid protection of protective fabrics. / Master of Science

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No description available.

The master´s thesis deals with the assessment of the state of the shore territory on the Brno reservoir, in the Osada area and subsequently the proposal for shore stabilization. As part of a personal visit to the area of interest, photographic documentation, geodetic focus and subsequent assessment of the current state of the abraded shores were made. Using the geodetic focus and data of water heights on the reservoir provided by the Povodí Moravy, s.p. the most numerous in the reservoir was evaluated in 2007-2017, the coastline retreat and the proposed shore stabilization were determined. There was suggested totaly eight measures were proposed against the further retreat of the shore line, which were incorporated into schemes and visualizations.

Esta Dissertação tem por objetivo estudar o comportamento de diferentes materiais sob a ação de desgaste micro-abrasivo. Como parte do trabalho, foi projetada e construída uma máquina de ensaio desgaste por micro-abrasão por esfera rotativa fixa, com configuração mecânica com diferenças em relação às observadas na literatura (Gee et al., 2005). Como corpos-de-prova, foram utilizadas pastilhas intercambiáveis de metal duro (classe P20) e aço ferramenta M2. As esferas foram de aço AISI 1010 cementado e aço AISI 52100 temperado e revenido. Durante os ensaios, foi inserida entre a esfera e o corpo-de-prova uma pasta abrasiva preparada com carbeto de silício preto, com tamanho médio de partícula de 5 µm. Inicialmente, foram realizados ensaios preliminares, com a finalidade de analisar não só o comportamento do equipamento, mas também estudar a transição entre os modos de desgaste que podem ocorrer durante o desgaste micro-abrasivo. A transição entre os modos de desgaste foi estudada em função da carga normal e dos materiais utilizados durante o ensaio. Os resultados obtidos indicaram boa reprodutibilidade do equipamento e coerência com resultados da literatura. Em seguida, em ensaios denominados definitivos, foram pesquisadas as atuações dos modos de desgaste abrasivo e a obtenção do regime permanente de desgaste. Os resultados mostraram que, com a variação da distância de deslizamento, houve alterações nas ocorrências dos modos de desgaste abrasivo. Por outro lado, em alguns ensaios, o coeficiente de desgaste tendeu a permanecer constante, o que caracteriza a obtenção do regime permanente de desgaste. Entretanto, em outros, o coeficiente de desgaste teve uma evolução aleatória com a distância de deslizamento, fornecendo indicativos de que o desgaste não entrou em regime. / This work presents a study on the behavior of different materials under the action of micro-abrasive wear. A micro-abrasive wear testing machine with fixed sphere was designed and constructed, presenting a mechanical configuration with differences with respect to those found in the literature (Gee et al., 2005). M2 tool steel and WC-Co P20 were used as testing specimen materials. Ball materials were cemented AISI 1010 steel and quenched and tempered AISI 52100 steel. During the tests, an abrasive slurry, prepared with black silicon carbide (SiC) particles (average particle size of 5 µm), was supplied to the contact between the specimen and the ball. Initially, preliminary tests were conducted to study the wear mode transitions that can occur during the micro-abrasive wear and to analyze the operational conditions of the equipment. The wear mode transitions were evaluated as a function of the applied normal load and of the materials used. The results indicated good reproducibility and qualitative agreement with those found in the litarature. Later, a new set of tests was conducted, which analyzed the evolution of the abrasive wear modes and the achievement of steady state wear as a function of sliding distance. The results indicated a continuous variation in the abrasive wear modes with sliding distance. Additionally, in some tests, the wear coefficient tended to stabilize in constant value, which characterizes the achievement of steady state regime. However, in other tests, the wear coefficient presented a non constant evolution of wear coefficient with the sliding distance, which denotes that the constant regime of wear was not obtained.

Esta Dissertação tem por objetivo estudar o comportamento de diferentes materiais sob a ação de desgaste micro-abrasivo. Como parte do trabalho, foi projetada e construída uma máquina de ensaio desgaste por micro-abrasão por esfera rotativa fixa, com configuração mecânica com diferenças em relação às observadas na literatura (Gee et al., 2005). Como corpos-de-prova, foram utilizadas pastilhas intercambiáveis de metal duro (classe P20) e aço ferramenta M2. As esferas foram de aço AISI 1010 cementado e aço AISI 52100 temperado e revenido. Durante os ensaios, foi inserida entre a esfera e o corpo-de-prova uma pasta abrasiva preparada com carbeto de silício preto, com tamanho médio de partícula de 5 µm. Inicialmente, foram realizados ensaios preliminares, com a finalidade de analisar não só o comportamento do equipamento, mas também estudar a transição entre os modos de desgaste que podem ocorrer durante o desgaste micro-abrasivo. A transição entre os modos de desgaste foi estudada em função da carga normal e dos materiais utilizados durante o ensaio. Os resultados obtidos indicaram boa reprodutibilidade do equipamento e coerência com resultados da literatura. Em seguida, em ensaios denominados definitivos, foram pesquisadas as atuações dos modos de desgaste abrasivo e a obtenção do regime permanente de desgaste. Os resultados mostraram que, com a variação da distância de deslizamento, houve alterações nas ocorrências dos modos de desgaste abrasivo. Por outro lado, em alguns ensaios, o coeficiente de desgaste tendeu a permanecer constante, o que caracteriza a obtenção do regime permanente de desgaste. Entretanto, em outros, o coeficiente de desgaste teve uma evolução aleatória com a distância de deslizamento, fornecendo indicativos de que o desgaste não entrou em regime. / This work presents a study on the behavior of different materials under the action of micro-abrasive wear. A micro-abrasive wear testing machine with fixed sphere was designed and constructed, presenting a mechanical configuration with differences with respect to those found in the literature (Gee et al., 2005). M2 tool steel and WC-Co P20 were used as testing specimen materials. Ball materials were cemented AISI 1010 steel and quenched and tempered AISI 52100 steel. During the tests, an abrasive slurry, prepared with black silicon carbide (SiC) particles (average particle size of 5 µm), was supplied to the contact between the specimen and the ball. Initially, preliminary tests were conducted to study the wear mode transitions that can occur during the micro-abrasive wear and to analyze the operational conditions of the equipment. The wear mode transitions were evaluated as a function of the applied normal load and of the materials used. The results indicated good reproducibility and qualitative agreement with those found in the litarature. Later, a new set of tests was conducted, which analyzed the evolution of the abrasive wear modes and the achievement of steady state wear as a function of sliding distance. The results indicated a continuous variation in the abrasive wear modes with sliding distance. Additionally, in some tests, the wear coefficient tended to stabilize in constant value, which characterizes the achievement of steady state regime. However, in other tests, the wear coefficient presented a non constant evolution of wear coefficient with the sliding distance, which denotes that the constant regime of wear was not obtained.

Master thesis aims to assessment of abrasion on banks of valley reservoir Brno. There was photodocumentation done and current conditions of abraded banks assessed during field survey. There was variables required to detect bottom of brasion cliff and maximal teoretical shift of bank line in the solved location calculated. There was suggested totaly nine types of precaution against other shift of bank line in cross-sections of abraded banks.