Novel inorganic-organic hybrid materials made previously in the laboratory have utilized acids catalysts such as HCI, acetic acid, toluene sulfonic acid and polystyrene sulfonic acid to catalyze the sol-gel reaction. The sol-gel reaction can also be catalyzed under near neutral (i.e. 5 < pH < 7) and basic conditions. The effects of synthesizing hybrid materials under near basic and basic conditions has not been studied. Attempts to synthesize hybrid materials from polytetramethylene oxide (PTMO) end functionalized with triethoxy silyl groups and, tetraethylorthosilicate (TEOS) under basic conditions met with only partial success. The films obtained had low mechanical stability. This was attributed to the low reactivity of the triethoxy species under neutral and basic conditions. In contrast, films with good mechanical stability were obtained when the TEOS was replaced with titanium tetraisopropoxide (TIOPR). The microstructure of the TIOPRlPTMO hybrid synthesized under near neutral conditions was generally similar to the acid catalyzed PTMOffIOPR hybrids. / Ph. D.

Examensarbetet har utförts under 10 veckor i uppdrag av Outokumpu Stainless AB via Uppsala universitet. Outokumpus produktion i Avesta tillverkar rostfritt stål, där en del av det producerade stålet slipas för att få en finare yta och minska defekter. I sliphallen finns 8st slipmaskiner som alla måste servas med nya slipskivor när de gamla är nedslipade. Detta utförs av två robotar som automatiskt ska åka ut i sliphallen och byta ut de gamla slipskivorna. Problematiken ligger i dessa robotar, vars automation endast fungerar fullt ut ett fåtal av gångerna. Examensarbetet gick således ut på att utvärdera dessa robotar samt generera förslag på förbättringsåtgärder. En stor del av arbetet fokuserades på analys av den befintliga skivbytesprocessen. Efter att förståelse erhållits för dagens process utfördes undersökningar i syfte att finna de faktorer som orsakar stopp i automationen samt dess konsekvenser. Till sist genererades lösningsförslag vars syften är att öka andelen automatiska byten. De huvudsakliga orsakerna till stoppen i automationen grundar sig i processens utformning, dess krav på precision och att ett flertal komponenter måste harmoniera för att byten ska fungera automatiskt. Bortsett från processens utformning är smuts, slitage, ej anpassad reglering och bristande rutiner faktorer som sätter stopp för automationen. Konsekvenser av problemet är säkerhetsrisker, frustration, tidsförluster för operatörer och ekonomiska förluster. Den instabila skivbytesprocessen påverkar i dagsläget inte nödvändigtvis ledtider på produkterna, men tvingar operatörer att byta slipskivor för tidigt vilket resulterar i outnyttjade slipskivor. Att öka andel automatiska byten är möjligt men kräver mycket arbete. Rutiner är viktigt, särskilt angående linjering av slipmaskinerna, vilket är en förutsättning för att det ska fungera. Även utbyte av slitna komponenter, optimering av reglertekniken och mindre programändringar är lösningar till en ökad andel automatiska byten. För att minska kostnaden för outnyttjade slipskivor krävs det att processen kan utföras snabbare och utan att påverka produktionen. Om företaget ska implementera en alternativ lösning är det viktigt att denna lösning inte kräver att operatörer behöver befinna sig i sliphallen. Detta grundar sig i säkerhetsrisker och minskad produktionskapacitet. Lösningen bör vara adaptiv för att ej behöva förlita sig på linjerade maskiner eller snäva toleranser. / This thesis in Mechanical engineering has been performed at the stainless steel manufacturer Outokumpu Stainless AB, through Uppsala University. At the company's production site some of the produced steel slabs are going through hot grinding in order to get the required surface finish, depending on the customer's demand on quality. There are 8 grinding machines in the grinding station, each of those needs to be provided with new abrasives when the old ones get to worn out. Two robots are installed to execute the abrasives change operation automatically, where each robot maintains 4 grinding machines, two coarse and two fine. This changing process is currently working fully automatically around one percent of the times which constitutes a problem. The thesis is about evaluation and improvement suggestions of this process, where the proportion of succeeded automatically replaced abrasives is in focus. A big part of the work has been based on analysing the existing process in purpose of understanding it fully. After enough knowledge about the process was achieved, investigations about the deficiencies of the process were conducted. Finally improvement suggestions were generated. The main cause of the automation failure is based on the process design and its precision requirements. The environment is tough and the forces are big which affects the process negatively. In addition there are a several components that need to harmonize in order for the abrasives replacement to work properly. Aside from the design of the process other critical factors are dust, component wear, deficient adapted regulation and lacking of alignment routines. Consequences of the failed automatically abrasive replaces are reduced safety, frustration among operators, time loss and economical losses. When the automation stops, the operators have to manually correct the errors alongside the grinding machines in the grinding area. The unstable processes does not necessarily affect the value-adding lead time but forces operators to change the abrasives too early which results in losses in form of non-fully utilized abrasives. Increasing the proportion of automatically fulfilled replaced abrasives is possible but requires much work. Routines are important, especially with alignment of the grinding machines which is a prerequisite for the process to succeed. Replacing of wear damaged components, optimizing the regulation and smaller programming changes are also solutions that contribute to an increasing proportion. To minimize the cost of unutilized abrasives the process is required to perform faster and without interfering with the production.   If the company wants to implement a different solution in form of an investment it is important that the solution does not require operators to be inside the grinding area. This is based on safety issues, also the risk of interrupting the production and creating a bottleneck, which can be crucial under more demanding periods. The solution should be a faster, more adaptive system and should not have to rely on alignment and narrow tolerances.

The basic objective of this study was to evaluate the environmental performance of two abrasives Copper Slag and Barshot in terms of productivity (in terms of area cleaned- ft2/hr), consumption and or used-abrasive generation rate (of the abrasive- ton/2000ft2; lb/ft2) and particulate emissions (mg/ft2; mg/lb; lb/lb; lb/kg; lb/ton). This would help in evaluating the clean technologies for dry abrasive blasting and would help shipyards to optimize the productivity and minimize the emissions by choosing the best combinations reported in this study to their conditions appropriately. This project is a joint effort between the Gulf Coast Region Maritime technology Center (GCRMTC) and USEPA. It was undertaken to simulate actual blasting operations conducted at shipyards under enclosed, un-controlled conditions on plates similar to steel plates commonly blasted at shipyards.

An experimental investigation has been undertaken to study the depth of cut in multipass abrasive waterjet (AWJ) cutting of an 87% alumina ceramic with controlled nozzle oscillation. The experimental data have been statistically analysed to study the trends of the depth of cut with respect to the process parameters. It has been found that multipass cutting with controlled nozzle oscillation can significantly increase the depth of cut. Within the same cutting time and using the same cutting parameters other than the jet traverse speed, it has been found that multipass cutting with nozzle oscillation can increase the depth of cut by an average of 74.6% as compared to single pass cutting without nozzle oscillation. Furthermore, a multipass cutting with higher nozzle traverse speeds can achieve a larger depth of cut than a single pass cutting at a low traverse speed within the same cutting time. A recommendation has been made for the selection of appropriate process parameters for multipass cutting with nozzle oscillation. In order to estimate the depth of cut on a mathematical basis, predictive models for the depth of cut in multipass cutting with and without nozzle oscillation have been developed using a dimensional analysis technique. The model development starts with the models for single pass cutting which are then extended to multipass cutting where considerations are given to the change of the actual standoff distance after each pass and the variation of kerf width. These predictive models has been numerically studied for their plausibility by assessing their predicted trends with respect to the various process variables, and verified qualitatively and quantitatively based on the experimental data. The model assessment reveals that the developed models correlate very well with the experimental results and can give adequate predictions of this cutting performance measure in process planning.

An experimental investigation has been undertaken to study the depth of cut in multipass abrasive waterjet (AWJ) cutting of an 87% alumina ceramic with controlled nozzle oscillation. The experimental data have been statistically analysed to study the trends of the depth of cut with respect to the process parameters. It has been found that multipass cutting with controlled nozzle oscillation can significantly increase the depth of cut. Within the same cutting time and using the same cutting parameters other than the jet traverse speed, it has been found that multipass cutting with nozzle oscillation can increase the depth of cut by an average of 74.6% as compared to single pass cutting without nozzle oscillation. Furthermore, a multipass cutting with higher nozzle traverse speeds can achieve a larger depth of cut than a single pass cutting at a low traverse speed within the same cutting time. A recommendation has been made for the selection of appropriate process parameters for multipass cutting with nozzle oscillation. In order to estimate the depth of cut on a mathematical basis, predictive models for the depth of cut in multipass cutting with and without nozzle oscillation have been developed using a dimensional analysis technique. The model development starts with the models for single pass cutting which are then extended to multipass cutting where considerations are given to the change of the actual standoff distance after each pass and the variation of kerf width. These predictive models has been numerically studied for their plausibility by assessing their predicted trends with respect to the various process variables, and verified qualitatively and quantitatively based on the experimental data. The model assessment reveals that the developed models correlate very well with the experimental results and can give adequate predictions of this cutting performance measure in process planning.

Processos de fabricação que fazem uso de abrasão como modo de remoção de material são discutidos constantemente pela literatura. Entretanto, a abrasividade, ou a capacidade de remoção de material pelos abrasivos pouco tem sido abordada na literatura especificamente para partículas micrométricas. Esta capacidade de remoção pode ser atribuída a variações da concentração, geometria, dureza e distribuição de tamanho das partículas no fluido abrasivo. Logo, um melhor entendimento acerca da abrasividade das partículas faz-se necessário para uma melhor caracterização dos modos e mecanismos atuantes no processo, visto que a seleção do abrasivo é um fator econômico significativo em diversos processos de fabricação, tais como retificação e hidroerosão. Esta dissertação tem por objetivo utilizar-se do ensaio de desgaste por micro abrasão para a avaliação da abrasividade de partículas de alumina e carbeto de boro. Como corpos-de-prova foram utilizadas amostras de aço AISI D2 (677 HRC) e as esferas de 25,4 mm de diâmetro foram de aço AISI 52100 temperado e revenido. Foram realizados ensaios com abrasivos diferentes de tamanhos semelhantes e ensaios com o mesmo abrasivo de tamanhos diferentes para verificar a influência da concentração do abrasivo, da rotação e do desgaste da esfera e do tempo de ensaio. As distribuições de tamanho das partículas foram determinadas através da técnica de difração a laser na forma de distribuição de frequência em volume e na forma de frequência acumulada. Além disso, a caracterização quanto à geometria, por meio do fator SPQ (parâmetro de ponta), foi realizada utilizando um programa computacional desenvolvido no Matlab. As distribuições de tamanho mostraram uma percentagem de volume de partículas finas maior nas amostras de carbeto de boro e uma percentagem de volume de partículas mais grossas superiores para a alumina. O valor de SPQ médio apresentou-se maior para o carbeto de boro do que para a alumina, quando com tamanhos médios diferentes. Porém para os abrasivos diferentes com tamanho médio semelhante, a alumina apresentou um valor maior para o parâmetro. Esse valor maior sugere uma maior capacidade de remoção de material. Os resultados mostraram que a variação do tempo de ensaio é responsável por uma mudança no modo de desgaste e que os abrasivos de Al2O3 apresentam menor abrasividade quando comparados aos abrasivos de B4C, pois o coeficiente de desgaste mostrou-se maior para este após o alcance do regime permanente. Um aumento da concentração do abrasivo e um acréscimo no tempo de ensaio levaram a um crescimento no volume de desgaste do material para ambos os abrasivos, enquanto que um aumento na rotação da esfera de ensaio não proporcionou um aumento significativo no volume de material removido. As durezas das partículas abrasivas e do corpo de prova e o tamanho e a angularidade dos abrasivos são utilizados para discussão das causas do regime permanente ter ocorrido em diferentes tempos para os dois abrasivos. / Manufacturing processes that use abrasion for material removal are constantly discussed in the literature. However, the abrasiveness, or the ability of material removal by particles has not been widely discussed in the literature specifically for micrometric particles. This removal capacity can be attributed to changes in the particle concentration, geometry, hardness and size distribution in the fluid abrasive. Therefore, a better understanding of the particles abrasiveness is necessary for a proper characterization of the modes and mechanisms acting in the process, since the abrasive selection is a significant economic factor in several manufacturing processes, such as grinding and hydroerosive grinding. The purpose of this work is to use the micro abrasion wear test to evaluate the abrasiveness of alumina and boron carbide particles. Samples of AISI D2 steel (677 HRC) and balls with 25.4 mm diameters quenched and tempered AISI 52100 steel were used. Tests were performed with different abrasives of similar sizes and with the same abrasive of different sizes to verify the influence of the abrasive concentration, ball rotation and wear and test time. Particle size distribution was determined by laser diffraction in terms of frequency distribution and cumulative frequency volumes. Moreover, the particle geometry characterization was also determined using the SPQ factor (Spike value) using a Matlab computer program. The size distribution indicated a higher percentage of fine particles for boron carbide and a higher percentage of coarse particles for alumina. The mean SPQ value was higher for boron carbide than for alumina with different average sizes. However, for different abrasives with similar average size, the alumina presented a bigger value for the parameter. This bigger value suggests a higher material removal capacity. The results show that test time is responsible for a change in the wear mode. Al2O3 particles presented a lower abrasiveness when compared to B4C particles because the wear coefficient was bigger for B4C after reaching the steady state regime. An increase in abrasive concentration and in test time led to a growth in material volume wear for both abrasives, while an increase in the ball rotation did not provide a significant increase in the material volume removed. The particles and specimen hardness and the abrasives size and angularity were used to discuss the causes of the steady state regime occur at different times for the two abrasives.

Processos de fabricação que fazem uso de abrasão como modo de remoção de material são discutidos constantemente pela literatura. Entretanto, a abrasividade, ou a capacidade de remoção de material pelos abrasivos pouco tem sido abordada na literatura especificamente para partículas micrométricas. Esta capacidade de remoção pode ser atribuída a variações da concentração, geometria, dureza e distribuição de tamanho das partículas no fluido abrasivo. Logo, um melhor entendimento acerca da abrasividade das partículas faz-se necessário para uma melhor caracterização dos modos e mecanismos atuantes no processo, visto que a seleção do abrasivo é um fator econômico significativo em diversos processos de fabricação, tais como retificação e hidroerosão. Esta dissertação tem por objetivo utilizar-se do ensaio de desgaste por micro abrasão para a avaliação da abrasividade de partículas de alumina e carbeto de boro. Como corpos-de-prova foram utilizadas amostras de aço AISI D2 (677 HRC) e as esferas de 25,4 mm de diâmetro foram de aço AISI 52100 temperado e revenido. Foram realizados ensaios com abrasivos diferentes de tamanhos semelhantes e ensaios com o mesmo abrasivo de tamanhos diferentes para verificar a influência da concentração do abrasivo, da rotação e do desgaste da esfera e do tempo de ensaio. As distribuições de tamanho das partículas foram determinadas através da técnica de difração a laser na forma de distribuição de frequência em volume e na forma de frequência acumulada. Além disso, a caracterização quanto à geometria, por meio do fator SPQ (parâmetro de ponta), foi realizada utilizando um programa computacional desenvolvido no Matlab. As distribuições de tamanho mostraram uma percentagem de volume de partículas finas maior nas amostras de carbeto de boro e uma percentagem de volume de partículas mais grossas superiores para a alumina. O valor de SPQ médio apresentou-se maior para o carbeto de boro do que para a alumina, quando com tamanhos médios diferentes. Porém para os abrasivos diferentes com tamanho médio semelhante, a alumina apresentou um valor maior para o parâmetro. Esse valor maior sugere uma maior capacidade de remoção de material. Os resultados mostraram que a variação do tempo de ensaio é responsável por uma mudança no modo de desgaste e que os abrasivos de Al2O3 apresentam menor abrasividade quando comparados aos abrasivos de B4C, pois o coeficiente de desgaste mostrou-se maior para este após o alcance do regime permanente. Um aumento da concentração do abrasivo e um acréscimo no tempo de ensaio levaram a um crescimento no volume de desgaste do material para ambos os abrasivos, enquanto que um aumento na rotação da esfera de ensaio não proporcionou um aumento significativo no volume de material removido. As durezas das partículas abrasivas e do corpo de prova e o tamanho e a angularidade dos abrasivos são utilizados para discussão das causas do regime permanente ter ocorrido em diferentes tempos para os dois abrasivos. / Manufacturing processes that use abrasion for material removal are constantly discussed in the literature. However, the abrasiveness, or the ability of material removal by particles has not been widely discussed in the literature specifically for micrometric particles. This removal capacity can be attributed to changes in the particle concentration, geometry, hardness and size distribution in the fluid abrasive. Therefore, a better understanding of the particles abrasiveness is necessary for a proper characterization of the modes and mechanisms acting in the process, since the abrasive selection is a significant economic factor in several manufacturing processes, such as grinding and hydroerosive grinding. The purpose of this work is to use the micro abrasion wear test to evaluate the abrasiveness of alumina and boron carbide particles. Samples of AISI D2 steel (677 HRC) and balls with 25.4 mm diameters quenched and tempered AISI 52100 steel were used. Tests were performed with different abrasives of similar sizes and with the same abrasive of different sizes to verify the influence of the abrasive concentration, ball rotation and wear and test time. Particle size distribution was determined by laser diffraction in terms of frequency distribution and cumulative frequency volumes. Moreover, the particle geometry characterization was also determined using the SPQ factor (Spike value) using a Matlab computer program. The size distribution indicated a higher percentage of fine particles for boron carbide and a higher percentage of coarse particles for alumina. The mean SPQ value was higher for boron carbide than for alumina with different average sizes. However, for different abrasives with similar average size, the alumina presented a bigger value for the parameter. This bigger value suggests a higher material removal capacity. The results show that test time is responsible for a change in the wear mode. Al2O3 particles presented a lower abrasiveness when compared to B4C particles because the wear coefficient was bigger for B4C after reaching the steady state regime. An increase in abrasive concentration and in test time led to a growth in material volume wear for both abrasives, while an increase in the ball rotation did not provide a significant increase in the material volume removed. The particles and specimen hardness and the abrasives size and angularity were used to discuss the causes of the steady state regime occur at different times for the two abrasives.

Indiana University-Purdue University Indianapolis (IUPUI) / Hypothesis: The interaction between the abrasive level and fluoride concentration of dentifrice slurries modulates the surface loss (SL) and remineralization of incipient enamel caries (IEC). Methods: Three types of IEC were created and six experimental slurries with different combinations of fluoride content and abrasive level were tested. In experiment 1, the three IEC were subjected to brushing (with experimental slurries) and remineralization cycles for 5 days. Fluoride concentrations (0 and 275 ppm as NaF) and abrasive levels (Low and High) were tested. SL was determined by optical profilometry at baseline and after 1, 3, and 5 days. In experiment 2, changes in IEC mineral content (Δ(ΔZ)C) and depth (ΔLC) were investigated at baseline and after the 5-day cycling with transverse microradiography. In experiments 3 and 4, SL of MeC and CMC lesions were further studied, respectively; testing not only fluoride concentration (275 and 1250 ppm as NaF) and abrasivity (low and high) of the slurry, but also the brushing frequency (1x, 2x, and 3x/day). Brushing-remineralization cycles were performed for 7 days. Statistical analyses were performed at 5% significance level. Results: Experiment 1: overall, brushing with the high-abrasive slurry caused more SL than with the low-abrasive. For CMC and MeC lesions, 0 ppm F had more SL than 275 ppm F only after day 3. Fluoride had no effect on the SL of HEC lesions. Experiment 2: fluoride and abrasives did not have a significant effect on IEC. HEC had significantly lower Δ(ΔZ)C than CMC and MeC, with CMC and MeC not differing from each other. Lesion type had no effect on ΔLC. Experiment 3: brushing CMC lesions 3x/day with 1250 ppm F increased SL compared to 1x/day, after 5 and 7 days. Study 4: brushing MeC lesions with high abrasive slurry containing 1250 ppm F increased SL after 5 and 7 days. Conclusions: The IEC tested showed different SL and remineralization behaviors. The fluoride content and abrasive level of the toothpaste showed to be relevant modulating the SL of enamel caries lesions as well as their remineralization behavior.