Thesis (Ph.D.)--University of Central Florida, 2009. / Adviser: W. Linwood Jones. Includes bibliographical references (p. 129-132).

O aspecto técnico das rochas de revestimento é o primeiro condicionante para o seu uso nas edificações, seguido das suas características tecnológicas, da tipologia do jazimento e dos possíveis defeitos decorrentes das etapas de extração e beneficiamento. O presente trabalho aborda os mecanismos que influenciam no processo de polimento, lembrando que a indústria ainda se baseia no empirismo, com generalizações não condizentes que aumentam o custo de produção das placas. Foram escolhidos três tipos de rochas \"graníticas\": Sienogranito (Vermelho Brasília), Migmatito (Jacarandá Rosado) e Monzogranito (Cinza Andorinha), por serem de alta comercialização e consideradas no processamento industrial como \"dura\", \"média\" e \"mole\", respectivamente. Foram ensaiadas no simulador de polimento de rochas (SPR), utilizando o abrasivo magnesiano e antes de iniciar o processo foi determinada a rugosidade superficial de cada amostra. Variando-se a carga aplicada na politriz, a velocidade, o tempo e monitorando a perda de massa associada ao brilho, foi possível estabelecer as condições ideais para os tipos de rochas estudadas. / Dimension stones aesthetics are the main factor considered in their use for buildings, followed by technological characteristics, deposit\'s typology and possible extraction and beneficiacion effects. This paper approaches the influential mechanisms on polishing process, considering that industry still bases itself on empiricisms, with incoherent generalizations that increase production slabs cost. Three types of granite rocks were evaluated: Sienogranite (Vermelho Brasília), Migmatite (Jacarandá Rosado) and Monzogranite (Cinza Andorinha), due to their highly commercialization. The rocks are classified at the industrial process as hard, medium and soft (respectively). They were tested with a polishing rock simulator through the use of magnesium abrasives and had the surface roughness pre-determined for each sample. By altering the polishing machine applied load, as well as speed and time, and having the brightness associated weight loss monitored, it was possible to stabilish ideal conditions for the studied rock types.

O polimento de rochas ornamentais na indústria brasileira é um processo empírico. Nesse processo, elementos como tempo, velocidade de rotação e carga aplicada na politriz são combinados de diversas maneiras para a obtenção do brilho. O presente trabalho, a partir de ensaios no Simulador de Polimento de Rochas (SPR), obteve informações mais precisas sobre quais combinações envolvendo essas variáveis são as mais eficientes para se atingir o brilho ideal em cada tipo de rocha. Para alcançar os resultados foram executadas e comparadas nove combinações para cada uma das rochas estudadas, considerando as influências das características composicionais, estruturais e texturais. Foram feitas modificações e adaptações nos aparelhos SPR e Glossmeter, uma vez que apresentavam a possibilidade de afetar a veracidade dos resultados. Os resultados e análises feitas mostram que é possível eliminar uma etapa abrasiva no processo de polimento. Cada tipo de rocha responde de maneira distinta em relação às combinações para obtenção do brilho ideal, levando à uma combinação específica para cada rocha. Os aprimoramentos do processo obtidos podem promover a redução custos para os fabricantes em relação a tempo, energia e abrasivos. / The ornamental stones polishing in the industry is considered an empirical process. In this process, variables such as time, rotation speed and intensity of the load applied are combined in different operation conditions to obtain the desired brightness. Using the Polishing Rocks Simulator (SPR), this present research aims to obtain information about which combinations of these variables are the most efficient to achieve the desired brightness in each type of rock. To achieve these objectives nine combinations were compared over three types of rocks in order to analyze the influence of each rock characteristics such as composition, structure and texture. Some modifications and adjustments were made on the Glossmeter and the SPR because they could influence the results accuracy. The obtained results and analysis shows that a step can be eliminated in the abrasive polishing process. Each type of rock responds differently to the employed combinations to reach the desired brightness. These analyses conduct to a specific combination for each rock. The achieved process improvement can reduce the costs for the industry in respect of time, energy and abrasives.

Este trabalho apresenta uma contribuição experimental cujo objetivo é fornecer elementos para o aprimoramento tecnológico das etapas de polimento de rochas ornamentais. Alguns aspectos da tribologia, ramo do conhecimento amplamente utilizado nas engenharias mecânica e de materiais, foram transferidos para o estudo do polimento de rochas ornamentais e subsidiaram a investigação da interação do tribossistema composto pela rocha, pelo abrasivo e por condições operacionais. Foi desenvolvido um equipamento em laboratório que possibilitou a simulação do processo de polimento, em diversas condições operacionais, considerando as variáveis tempo, velocidade de rotação e intensidade das cargas aplicadas. Foram comparados polimentos, em condições industrial e laboratorial de rochas graníticas, visando estabelecer as influências das suas características composicionais, texturais e estruturais no processo. Os resultados permitiram definir as condições ideais para a obtenção de melhor qualidade no brilho das rochas e representa uma contribuição tanto para o entendimento do processo de polimento propriamente dito como também para a otimização do processo industrial. / This work shows an experimental contribution which goal is to provide elements to the technological improvement of each step of dimension stones polishing. Some aspects of tribology, a discipline of mechanical and material engineering, has been used on the research of dimension stones polishing and has supported the investigation of the interaction of the tribosystem composed of rock, abrasive and operational conditions. For this research, a device was developed in the lab in order to make possible the simulation of the polishing process at different operational conditions, considering the variables time, rotation speed, and intensity of the loads applied. The polishing of granite rocks at industrial and lab conditions has been compared, aiming at determining the influence of each rock characteristics such as mineral composition, texture and structure during the process. The results allowed for the definition of the ideal conditions to obtain the best quality of rock brightness and they represent a contribution to the understanding of the polishing process itself as well as provide an optimization of the industrial process.

O Brasil ocupa uma posição de destaque no cenário mundial da produção e exportação de rochas ornamentais devido a sua diversidade litológica e por abrigar todas as fases da cadeia produtiva, desde a lavra até o esquadrejamento de ladrilhos. No entanto, apesar da grande importância que este setor representa para a balança comercial mineral do país, muitos mecanismos físicos de seus processos industriais ainda não são corretamente entendidos, sendo realizados na maioria das vezes de forma empírica. A etapa de polimento das rochas ornamentais, que pode ser descrita como um processo em que o desgaste provocado por ferramentas abrasivas elimina as superfícies rugosas herdadas na etapa da serragem, ainda é um destes processos cujas variáveis envolvidas permanecem escassas de estudos. Na tentativa de torná-lo menos subjetivo, o Grupo de Tecnologia de Rochas (GTR) da Área de Pós-graduação em Geotecnia da EESC/USP, tem desenvolvido pesquisas abordando o enfoque da tribologia ao polimento, porém não esgotando todos os parâmetros envolvidos. Dando continuidade a estes estudos, a presente pesquisa abrange a simulação de polimento de 2 rochas \"graníticas\" utilizando-se dois tipos de abrasivos: os magnesianos, de uso mais tradicional, e o resinóide, um dos mais modernos utilizados atualmente. Foram usadas 9 combinações distintas, entre velocidade de rotação (200, 400 e 600 rpm), tempo (2, 4 e 6 minutos) para carga de 1 bar. Dentre as amostras submetidas ao processo, as com textura grossa e inequigranular mostraram certa limitação quanto à representatividade do equipamento SPR no desgaste abrasivo, não refletindo (necessariamente) a realidade do polimento industrial de granitos com mineralogia e textura similares. No entanto, em amostras com textura fina e equigranular, com baixa resistência à abrasão Amsler, os resultados expressos pelas perdas de massa (rocha e abrasivo) mostraram melhores superfície polida e qualidade de brilho, além de maior eficiência no polimento. / Brazil occupies a leading position on the global scenario of production and export of ornamental stones due to its geological diversity and by accommodate all stages of the supply chain, from quarrying to the tiles finishing. However, despite the great importance of this sector, many physical mechanisms of its industrial processes are still not properly understood and performed most often empirically. The polishing of ornamental stones, which can be described as a process where wearing caused by abrasive tools eliminates rough surfaces coming from the sawing stage, it is still one of the processes where the variables involved remain in scarce studies. In an attempt to become this process less subjective, the Geotechnical Engineering postgraduation department from the University of São Paulo (USP) at São Carlos School of Engineering has been developing researches approaching the focus of tribology in the polishing, but not exhausting all parameters involved. Following such studies, this research covers the polishing simulation of two granitic stones using two types of abrasives: the magnesian, more traditional, and resinoid, one of the most modern presently used. Nine different combinat ions were used between rotation speed (200, 400 and 600 rpm) and time (2, 4, and 6 minutes) to the 1 bar load. Among the samples subjected to the process, those with coarse and inequigranular texture showed some limitation to the representativeness of the SPR equipment in abrasive wearing, not necessarily reflecting the reality of industrial polishing of granites with similar mineralogy and texture. However, samples with fine and equigranular texture with low abrasive resistance, the results expressed by mass loss (stone and abrasive) showed better quality of the polished surface and gloss, besides a more efficient polishing.

Contrast sensitivity to vertically oriented grating patterns with a sinusoidal luminance profile were examined between groups of observers varying either in gender or age. For each observer at each of the seven spatial frequencies tested (.75, 1.5, 3, 6, 7.5, 10, 15 cyc/deg) threshold values were calculated for either ascending or descending trials as well as a combination of both. These threshold values were numerically transformed into sensitivity values and contributed to a group mean contrast sensitivity score for each spatial frequency. No significant effect of gender was found but younger observers (mean age=22.6 yrs.) exhibited significantly better contrast sensitivity than the older aged group (mean age=66.2 yrs.) for ascending trials at 3, 1.5 and .75 cyc/deg--the lowest spatial frequencies tested. Contrast sensitivity was also correlated with various measures. These findings were discussed in relation to the existing literature on age and spatial contrast sensitivity and since the machine used to examine the contrast sensitivity function (CSF) in this study utilized a laser interferometric method of stimulus generation, possible neurological changes with aging to explain this noted loss were also considered. Also discussed were various parameters that effect the CSF with a view toward explaining the disparate findings of various existing studies of age and the CSF. / Arts, Faculty of / Psychology, Department of / Graduate

Denna studie har gått ut på att studera hur färg och storlek på cirklar påverkar hur hårt man trycker på tangenter i olika spelversioner. Vi har skapat tre versioner av ett spel där användaren skulle översätta cirklars utseende genom att trycka olika hårt på tangenter. Samtliga versioner av spelet baserades på fallande cyanfärgade cirklar ivertikalled. Den fallordning cirklarna föll enligt, hade alla versioner gemensamt. Skillnaden för versionerna var att cirklarna uttrycktes olika i färgton och storlek. Vi ansåg att en studie kring hur användare interagerade genom olika kombinationer av färgton och storlek kunde bidra till hur man väljer att bygga upp grafiska objekt i datorspel. Denna studie baserades på bland annat experiment inom perceptions-, färg- och ljusteori samt hur former fungerar som informationsbärare. Resultaten från undersökningen visade på att ha flera föränderliga grafiska komponenter gav oftast bäst träffsäkerhet i styrka utifrån spelet. Trots det så hade de andra versionerna vissa delresultat som var avsevärt bättre än versionen med fler föränderliga grafiska komponenter. Resultaten från undersökningen visade även på att deltagarna antog sig veta vilket grafiskt gränssnitt som passade dem bra och mindre bra, men hur de egentligen presterade motbevisade det. Utifrån detta drog vi slutsatsen att effektiviteten att kommunicera en fysisk storhet var olika beroende på person, men att det mest pålitliga alternativet tenderade att vara en kombination av de båda föränderliga komponenterna.

There are numerous applications for airborne imaging systems in remote sensing, and this thesis deals with a new microwave polarimetric radiometer technique for inferring ocean surface wind direction [3, 5, 7]. This technique is based upon the anisotropy of the polarized ocean blackbody emissions at microwave frequencies relative to the azimuth angle between the microwave radiometer antenna "look" direction and the direction of the wind. Because of the weak wind direction signature, it is important that all systematic brightness temperature (Tb) errors be eliminated, especially those that vary with the radiometer antenna scan position (look direction). This can be accomplished either in hardware implementation or through data processing corrections. Unfortunately, the misalignment of the axis of rotation for a conical-scanning imager can introduce such azimuthally dependent errors of significant magnitude. As the title suggests, the analysis of the resulting Tb errors caused by static and dynamic time-varying aircraft attitude errors is the main thrust of this thesis. In this thesis, we present analytical models developed to account for platform attitude changes on measured ocean microwave brightness temperature collected by a conically scanning radiometer. Data processing procedures for removing unwanted variations in ocean brightness temperatures are outlined. The analytical models are validated by making comparisons between modelled and measured Tb's obtained by the Conically Scanning Two-Look Airborne Radiometer (C-STAR). Results demonstrated that the analytical Tb model can accurately predict the measured polarized Tb's under actual flight conditions.

no / We investigated the brightness (i.e., perceived luminance) of isolated L- and M-cone pulses to seek a perceptual correlate of our previous reports that M-on electroretinograms resemble L-off responses, implying the operation of post-receptoral opponent processing. Using triple silent substitutions, cone increments were generated in a 4-primary ganzfeld, masked by random positive or negative luminance bias. The results show that M-cone increments decrease in brightness, while L-cone increments increase. These differences became smaller as field size reduced; this was not eccentricity or area dependent. We speculate about early retinal input into brightness perception.

Recent years have seen an increasing focus on electric energy consumption as well as ecology in relation to human health. It is crucial to maintain the so called lighting comfort which is influenced by a wide range of lighting parameters, including illuminance, brightness, balance of illuminance, and glare. Thanks to all these parameters we can design lighting systems in such a way as to prevent energy waste and far too rapid deterioration of eyesight. This study therefore focuses on glare evaluation of indoor and outdoor lighting systems. In order to comprehend the issue thoroughly, a detailed description of human eyes and their functions is provided, followed by definitions of glare and types of glare. An overview of different calculations for indoor and outdoor glare is provided, considering the evaluation of daylight glare in terms of complex lighting systems. The study mentions several options involving unconventional methods for measuring glare (brightness). In the analytical part of the study, outdoor glare on Kolejní Street and indoor glare at the Prof. Brauner Hall at VUT measurements were obtained using brightness analyzer (an unconventional method). The thesis is concluded with a comparison of the conventionally and unconventionally obtained measurements, considering their respective advantages.