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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Estudo comparativo do polimento de \"granitos\" com diferentes tipos de abrasivos / Comparative study of \"granites\" polishing with different types of abrasives

Phillipe Fernandes de Almeida 25 April 2014 (has links)
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.
42

Investigação da influência das características petrográficas e da rugosidade de placas de \"granitos e mármore\" fixadas com argamassas / Investigation of the influence of the petrographic characteristics and the roughness of plates \"granites and marble\" set with mortar

Lizandra Nogami 21 February 2013 (has links)
No presente trabalho foram comparadas as aderências e propriedades de cinco tipos de argamassas colantes para fixar ladrilhos de \"granitos e mármore\" em pisos e revestimentos de edificações. Uma das argamassas é industrializada e específica para granitos e mármores, outra preparada em laboratório para fixação de porcelanatos e mais três argamassas também desenvolvidas em laboratório, tendo como base a argamassa para porcelanato. Para a realização do ensaio de aderência foram escolhidos oito tipos diferentes de granitos e um mármore de grande aceitação comercial. Os resultados evidenciaram a excelente qualidade das argamassas colantes desenvolvidas em laboratório as quais superaram a industrializada. Verificou-se também que a aderência de todas as argamassas está relacionada à rugosidade das placas e às características mineralógicas dos \"granitos\". / In this paper, the adherence of five types of adhesive mortars used for fixing granite and marble tiles in floors and linings of buildings were compared. One of the mortars is industrialized and specific for granites and marbles, another one, is prepared in the laboratory for setting porcelains, and three other types of mortars, also developed in the laboratory, having the porcelain mortar as a base (were used). To carry out the adherence test, eight types of granites and one marble of large commercial acceptance were selected. The results of the tests showed the excellent quality of the adhesive mortars developed in the laboratory, which were considered superior than the industrialized type. Likewise, it was noted that the adherence of all types of mortars is related to the roughness of the plates and to the mineralogical characteristics of the granites.
43

Nurse Practitioners' Use of Ultrasound to Diagnose Kidney Stones in the Emergency Department

Schmidtmann, Amanda, Schmidtmann, Amanda January 2016 (has links)
Background: Kidney stones are a common, painful disorder that can affect as many as one of 11 people in the United States (Goldfarb & Arowojolu, 2013). The gold standard for diagnosing kidney stones is currently computed tomography (CT). However, because CT scans emit radiation during the exam, they could be causing more harm than good. According to recent research, ultrasound may be used to diagnose kidney stones with close to similar accuracy and reliability. Ultrasounds are also safer and more cost effective for patients and the healthcare system. Purpose: The purpose of this project is to describe nurse practitioners (NPs) use of ultrasound to diagnose kidney stones in the emergency department (ED). The information from this project was compared with the recent literature and used to develop an evidence-based practice recommendation for diagnosing suspected kidney stones in the ED. Methods: A 15-item survey was mailed to emergency department NPs across the United States. Descriptive statistics were used to analyze the quantitative results. One open-ended question was also posed, and findings were grouped by commonalities of clinical experiences. Results: Analysis of survey responses indicates that all of the respondents use CT scan to diagnose kidney stones. However, the majority of the respondents also feel that ultrasound could be used in the ED to diagnose kidney stones. The results also demonstrate that even though there is no nationally or internationally accepted standardized guideline for diagnosing kidney stones in the ED, many EDs across the country are instituting their own protocols.
44

O papel dos bosques agroflorestais para a diversidade da avifauna na paisagem fragmentada do Pontal do Paranapanema, SP - Brasil / The role of agro-forest patches for bird diversity in Pontal do Paranapanema (SP - Brazil) fragmented landscape.

Dennis Driesmans Beyer 10 May 2006 (has links)
A fragmentação de hábitats, e conseqüente isolamento de populações animais e vegetais, tem sido apontada como uma das principais ameaças à biodiversidade. Os elementos de conexão são estruturas que favorecem o deslocamento de organismos pela paisagem fragmentada. Um destes elementos, os trampolins ecológicos, também chamados de pontos de ligação ou stepping stones, são pequenas áreas de hábitat dispersas na matriz de não habitat, que potencialmente podem aumentar a conectividade na paisagem, reduzindo a probabilidade de extinção de diversas espécies. Este trabalho foi desenvolvido nos municípios de Teodoro Sampaio e Euclides da Cunha, localizados na região do Pontal do Paranapanema, Estado de São Paulo. Foram selecionadas duas paisagens com situações distintas no que se refere à presença dos elementos de conexão: Paisagem da Água Sumida (AS) e Paisagem da Ponte Branca (PB). Para a amostragem da avifauna utilizou-se o método do ponto fixo, no qual os pontos foram alocados distantes pelo menos 200m uns dos outros e o tempo de observação foi de 10 minutos por ponto. A coleta de dados em campo ocorreu nos meses de novembro e dezembro de 2003 e janeiro de 2004. Em cada paisagem foram realizadas quatro visitas. Em função deste levantamento, foi calculado o Índice Pontual de Abundância (IPA) para cada espécie em todos os pontos amostrados. Diversos bosques agroflorestais foram estudados, a fim de se verificar se eram utilizados pela avifauna, o que seria um indicativo da potencialidade destes bosques como trampolim ecológico. Foram também incluídos a matriz de pasto e os elementos de conexão: corredores ecológicos e pequenos fragmentos naturais. Os dados obtidos foram comparados com outro estudo conduzido nos fragmentos grandes. Foi observada uma diferença na composição da avifauna entre os diversos tipos de hábitats considerados, mas que ainda pouco deve refletir no aumento de fluxo pela paisagem das espécies florestais. Estas espécies na maior parte das vezes foram somente observadas nos fragmentos grandes e, aparentemente, não usam os bosques ou qualquer outro elemento de conexão, provavelmente devido ao elevado grau de isolamento destes e à hostilidade da matriz. Apesar de ter sido observado que os sistemas agroflorestais ainda não beneficiam grande parte da avifauna dependente de floresta, os resultados apontam que as ações de manejo nos assentamentos rurais começam a ter reflexos na diversidade na escala da paisagem da região, além de fornecer sustento para as famílias assentadas. Estes benefícios provavelmente serão maximizados com a intensificação dos processos de implantação de novos bosques agroflorestais, recuperação das matas ciliares e melhoramento da qualidade da vegetação dos remanescentes florestais. / Habitat fragmentation and consequent isolation of fauna and flora populations have been mentioned as one of the most critical threat for the biodiversity. The landscape elements are structures that increase the biota movements throw landscape. One of these elements is the stepping stones, which are small portions of habitat spread in matrix, and potentially could increase landscape connectivity, reducing extinction probability of a number of species. This study was conducted in Pontal do Paranapanema, State of São Paulo, Brazil, in two different areas concerning the presence or absence of some of the landscape elements: Landscape of Água Sumida (AS) and Landscape of Ponte Branca (PB). Field work had happened from November 2003 to January 2004. Avifauna was surveyed by point counts, where birds were registered for 10 minutes. The points were located at least 200m far from another, and each point was visited four times. Punctual Abundance Index (IPA) were calculated for birds species in all surveyed points. Some agro-forest patches were surveyed to verify the avifauna presence, which would be an indication of the potentially effect of stepping stones. Matrix of pasture, corridors and smalls fragments of native forest were also surveyed. The data obtained were compared to big fragments data of another study. There were differences of birds species compositions among all kinds of habitat considered, but it does not indicate increase of movements of forest species throw landscape. These species were most of the time registered into the large forest fragments, and they did not use agro-forest patches nor landscape elements, probably due the isolation caused by matrix hostility. Despite agro-forest system still do not increase movements of forest birds, the results suggests that environment management in settleland areas interfere on the biodiversity in landscape scale in this region, besides provide support for settled families. These benefits probably will be optimized with implantation of new agro-forest patches, revegetation of riparian areas and quality improvement of vegetation of residual woodlots.
45

Molecular Studies on Calcium Oxalate Kidney Stones: A Window into the Pathogenesis of Nephrolithiasis

Canela, Victor Hugo 05 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Nephrolithiasis will affect one-in-eleven people, and more than half of those individuals will have stone recurrence within a decade of their first episode. Despite decades of biomedical research on nephrolithiasis and extraordinary advances in molecular and cell biology, the precise mechanisms of kidney stone formation are not fully understood. Currently, there are limited treatments or preventative measures for nephrolithiasis. Therefore, it is crucial to scrutinize kidney stones from a molecular and cell biology perspective to better understand its pathogenesis and pathophysiology; and to, hereafter, contribute to effective therapeutic targets and preventative strategies. Kidney stones are composed of an admixture of crystal aggregated material and an organic matrix. 80% of all kidney stones are composed of calcium oxalate (CaOx) and half of all CaOx patients grow their stones on to Randall’s plaques (RP). RP are interstitial calcium phosphate mineral deposits in the renal papilla. Thus, we developed and optimized methodologies to directly interrogate CaOx stones. CaOx stones were demineralized, sectioned, and imaged by microscopy, utilizing micro CT for precise orientation. Laser microdissection (LMD) of specific regions of stone matrix analyzed by proteomics revealed various proteins involved in inflammation and the immune response. Analyses on jackstone calculi, having arm protrusions that extend out from the body of the stone, revealed that they are a rare subtype of CaOx stone formation. Micro CT analyses on 98 jackstones showed a radiolucent, organic-rich core in the arm protrusions. Fluorescence imaging on RP stones showed consistent differences in autofluorescence patterns between RP and CaOx overgrowth regions. Moreover, cell nuclei were discovered with preserved morphology in RP regions, along with variable expressions of vimentin and CD45. In comparing spatial transcriptomic expression of reference and CaOx kidney papillae, CaOx patients differentially expressed genes associated with pathways of immune cell activation, reactive oxygen damage and injury, extracellular remodeling, and ossification. Our findings provide novel methodologies to better understand the role of molecules and cells in CaOx stone matrix. Several of the proteins and cells identified in these studies may serve as potential biomarkers, and future therapeutic targets in preventing kidney stone disease.
46

Percutaneous Nephrolithotomy for Renal Stones Following Failed Extracorporeal Shockwave Lithotripsy: Different Performances and Morbidities

Zhong, Wen, Gong, Ting, Wang, Liang, Zeng, Guohua, Wu, Wenqi, Zhao, Zhigang, Zhong, Weide, Wan, Shaw P. 01 April 2013 (has links)
The purpose of this study is to summarize the results of percutaneous nephrolithotomy (PCNL) for renal stones following failed extracorporeal shockwave lithotripsy (SWL), and to investigate the effect of previous SWL on the performances and morbidities of subsequent PCNL. Sixty-two patients with a history of failed SWL who underwent PCNL on the same kidney (group 1) were compared to 273 patients who had received PCNL as first treatment choice (group 2). Patient demographics, stone characteristics, operative findings, and complications were documented and compared. Groups 1 and 2 had similar patient demographics and stone characteristics. Mean time to establish access was comparable in both groups (10.5 ± 4.2 vs. 9.6 ± 4.5 min, p = 0.894). Time required to remove stones and total operative time were longer in group 1 (71.5 ± 10.3 vs. 62.3 ± 8.6 min, p = 0.011 and 95.8 ± 12.0 vs. 80.6 ± 13.2 min., p = 0.018, respectively). Group 1 had lower clearance rate compared to group 2 (83.9 vs. 93.4 %, p = 0.021), while postoperative complications were similar in both groups. Scattered stone fragments buried within the tissues made the procedure more difficult for stone fragmenting and extracting, which lead to longer operative time and inferior stone free rate. However, the PCNL procedure was safe and effective in patients with failed SWL. The risk of complications was similar and clearance rate was encouraging.
47

Percutaneous Nephrolithotomy for Renal Stones Following Failed Extracorporeal Shockwave Lithotripsy: Different Performances and Morbidities

Zhong, Wen, Gong, Ting, Wang, Liang, Zeng, Guohua, Wu, Wenqi, Zhao, Zhigang, Zhong, Weide, Wan, Shaw P. 01 April 2013 (has links)
The purpose of this study is to summarize the results of percutaneous nephrolithotomy (PCNL) for renal stones following failed extracorporeal shockwave lithotripsy (SWL), and to investigate the effect of previous SWL on the performances and morbidities of subsequent PCNL. Sixty-two patients with a history of failed SWL who underwent PCNL on the same kidney (group 1) were compared to 273 patients who had received PCNL as first treatment choice (group 2). Patient demographics, stone characteristics, operative findings, and complications were documented and compared. Groups 1 and 2 had similar patient demographics and stone characteristics. Mean time to establish access was comparable in both groups (10.5 ± 4.2 vs. 9.6 ± 4.5 min, p = 0.894). Time required to remove stones and total operative time were longer in group 1 (71.5 ± 10.3 vs. 62.3 ± 8.6 min, p = 0.011 and 95.8 ± 12.0 vs. 80.6 ± 13.2 min., p = 0.018, respectively). Group 1 had lower clearance rate compared to group 2 (83.9 vs. 93.4 %, p = 0.021), while postoperative complications were similar in both groups. Scattered stone fragments buried within the tissues made the procedure more difficult for stone fragmenting and extracting, which lead to longer operative time and inferior stone free rate. However, the PCNL procedure was safe and effective in patients with failed SWL. The risk of complications was similar and clearance rate was encouraging.
48

“When you see me, weep” : The archaeology of the hunger stones of Europe.

Odbratt, Ivan January 2023 (has links)
This thesis investigates the phenomenon of hunger stones and their resurgence due to climate change-induced droughts, shedding light on their evolving societal significance. The initial focus lies on understanding the origins of the term and exploring how humanity has historically adapted to and remembered climatic transformations. A noteworthy aspect of this research revolves around the role of various objects worldwide serving as mnemonic devices, alongside a consideration of distinct cultural perceptions of time. Special emphasis is given to hunger stones that gained broad attention through social and traditional media in August 2022, owing to the droughts and their ominous inscriptions. It is posited that these stones likely served as hydrological markers or epigraphical reminders during periods of low water levels. The thesis delves into the approximately 900-year-old history of these stones in Europe, examining a range of hunger stones, beginning with the most renowned one located in Děčín, northern Czechia. Comparisons are made to other hydrological markers from around the globe, including Egypt's Nilometers and the intriguing White Crane Ridge in China. Furthermore, contemporary climate change is discussed, and the research explores potential parallels with past climatic conditions, concentrating on rivers as both physical and societal artefacts. In examining the relationship between humans and their environment, the thesis evaluates the effects of this relationship on human food systems, highlighting how the quest for food security has frequently led to the demise of cultures and species. A significant part of this research is devoted to examining memory, transitioning from tangible memory to social memory, and exploring the evolution of landscapes due to religious and other cultural developments.The concluding part of the thesis provides an analysis of how humans have dealt with food scarcity and their attempts to relay these struggles to future generations. It posits that the hunger stones serve as custodians of memory, maintaining relevance despite shifting interpretations over time.
49

QUANTITATIVE AND QUALITATIVE INVESTIGATIONS INTO URINARY CALCULI USING INFRARED MICROSPECTROSCOPY

Anderson, Jennifer Christine 29 March 2007 (has links)
No description available.
50

CAPABILITIES, LIMITATIONS AND APPLICATIONS OF ATR-FTIR IMAGING

Ling, Chen 25 June 2014 (has links)
No description available.

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