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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.
131

Evaluation of an automated multiplex real-time RT-PCR assay for rapid detection of Influenza A and B viruses

Broddesson, Sandra January 2015 (has links)
Influenza is a viral infection that affects global health and economy with its endemic and sometimes pandemic spread. Rapid detection of Influenza viruses enables antiviral use and can bring financial savings. It is also essential for the global surveillance of prevalent Influenza strains. RT-PCR is considered the most specific and sensitive method for detection of Influenza, but Influenza mutates at a high rate and it is therefore crucial that RT-PCR methods are updated regularly. In 2014, Cepheid released their Xpert Flu/RSV XC assay, which can detect Influenza A and B and RSV by multiplex RT-PCR in approximately one hour. The aim of this study was to evaluate this assay at Laboratoriemedicin Västernorrland by using the laboratory’s previous PCR assay for detection of Influenza viruses as reference method. Real-time RT-PCR was used to compare Xpert Flu/RSV XC to the reference method. A dilution series was performed to estimate the methods’ PCR efficiencies and precision was calculated from quadruplicates of a positive control sample. Clinical specimens (n=42) were used to evaluate the diagnostic sensitivity and specificity of Xpert Flu/RSV XC. Objective statistical analysis of PCR data was performed and discussed. The Xpert Flu/RSV XC was equivalent to the reference method and demonstrated high diagnostic sensitivity and specificity. Estimated PCR efficiencies were however low. With the introduction of Xpert Flu/RSV XC to the laboratory follows many potential benefits, primarily in form of a simplified pre analytical procedure and a shortened analysis time. The Xpert Flu/RSV XC assay enables fast diagnosis of Influenza infection.
132

Assessment Of Quality And Quantity Of Leachate From The Municipal Solid Waste Landfill Of Bursa

Akyol, Selin 01 September 2005 (has links) (PDF)
In this study, regularly measured long-term leachate data from Bursa Municipal Solid Waste Landfill (MSWL) were analyzed using conventional statistical, time series and factor analyses to investigate in detail the temporal variability of leachate quality and quantity, trend, randomness, seasonality and the auto- and cross- correlations of leachate pollutants. Evaluating the results of data analyses, leachate management recommendations, including sampling strategies in monitoring programs and treatment alternatives for old and fresh leachates, were developed. Statistically analyzed leachate parameters included BOD, COD, pH, SS, electrical conductivity, total CrO4, Cr6+, Fe, Cu, Zn, Pb, Cd, CN-, Cl, F, total P, NH4-N, total N, SO4, S2-, total alkalinity and leachate flow rate. Results indicated that the majority of pollutant concentrations varied in large ranges. Leachate parameters usually showed non-normal distributions and high variability in the closed T Valley compared to the open Main Valley. The majority of leachate parameters was autocorrelated and had statistically significant correlations amongst themselves. Factor analysis showed that different inter-relationships were present between leachate parameters for closed and open valleys. The sampling frequency and the number of leachate parameters need to be measured were determined to be higher for open landfills than for closed landfills. It was recommended that leachates, having high organic strength, in open landfill be treated using biological and physical/chemical processes. However, after the closure of the landfill, physical/chemical processes were recommended for leachate treatment, as it gradually completes transition from fresh to old leachate.
133

Three-dimensional pavement surface texture measurement and statistical analysis

Liu, Qingfan 09 January 2016 (has links)
Pavement texture has been measured predominantly by using two-dimensional (2D) profile methods. The 2D profile based mean profile depth (MPD) is still the well accepted texture index which has been found inadequate to characterize pavement texture especially when tire/pavement friction and noise are involved. There is a lack of standard 3D texture indices which show strong correlation with pavement friction and noise. There is a need to use 3D texture measurement for more comprehensive understanding of texture. The objectives of this thesis are to characterize pavement surfaces using 3D texture parameters based on 3D texture measurement and to explore the relationship between 3D texture parameters, pavement friction, and pavement noise. Field tests are conducted at various pavement sections for the measurements of texture, friction, and noise. The tested pavements include Interstate highway, MnROAD test facilities, airport runway, and municipal streets. The findings and contributions of this thesis are: • The pavement surface texture is measured in a 3D manner by using a line-laser scanner with both horizontal sample interval and vertical accuracy better than 0.05 mm. • A 3D texture analysis procedure with discrete wavelet transform (DWT) is proposed to separate macrotexture from microtexture and to define texture indices independently. • 3D parameters for macrotextures and microtexture are proposed and verified by field tests. • The relationship between 3D and 2D macrotexture indices [i.e. SMTD and MPD; Sq and root mean square roughness (RMSR)] are established, which is useful for the purposes of data comparison between 3D and 2D methods. • The relationship is investigated between 3D macrotexture parameters (SMTD and Sq) and pavement friction and noise. • It is found that texture distribution indices (i.e. Ssk and Sku) are significant contributors to pavement friction and noise. The new 3D texture analysis procedure and texture indices proposed in this thesis can be used to characterize various pavement textures (concrete pavement, asphalt pavement, and pavement contains recycled materials) in 3D manner, to compare 3D with 2D texture measurement/indices for quality control purposes, and to evaluate and predict pavement friction and noise. / February 2016
134

O impacto do crescimento da receita no resultado final das empresas

Haushahn, Carlos Daniel January 2006 (has links)
A presente dissertação relata o estudo efetuado sobre a correlação existente entre crescimento na receita das empresas e o resultado final destas empresas, conforme avaliado pelo EVA (Valor Econômico Agregado). O crescimento de uma empresa é uma decisão sempre bastante polêmica, dentro de uma organização. Vários aspectos que norteiam a decisão sobre quanto e como crescer devem ser levados em consideração pelos seus administradores, para que, mediante um planejamento bem efetuado, a empresa consiga desempenhar suas atividades em um ambiente menos turbulento, evitando assim os sobressaltos e perigos que surgem quando as decisões são tomadas sem os devidos planejamentos e cuidados. No decorrer do trabalho, discorre-se sobre diversas técnicas utilizadas para a mensuração de resultados em empresas. Em especial, é analisado o EVA, que foi o instrumento utilizado nas empresas avaliadas para a mensuração dos seus resultados. Também são destacados os modelos de mensuração de resultados descritos por Michel Fleuriet e Dante Matarazzo. A questão central do trabalho é: “O resultado final das empresas é impactado pelo crescimento de suas receitas?”. Como objetivo central do trabalho, foi estabelecido o de analisar a relação existente entre o resultado de uma empresa, conforme medido pelo EVA, e o crescimento na receita da empresa. Ainda, como objetivos secundários, foram selecionados os de analisar de que forma as empresas com melhores resultados finais compõem suas fontes de recursos, e qual a correlação existente entre o resultado final e o crescimento anual da receita, a taxa de crescimento interno e a taxa de crescimento sustentável. A análise efetuada, a partir de uma amostra dos resultados de 34 empresas, demonstrou que, para as hipóteses avaliadas, pode ser afirmado que tal correlação, se existente, é fraca, ou seja, para a amostra estudada, a correlação entre o crescimento de receita e o resultado final é baixa. / The present work explains the study made upon an existing correlation between the growth on the incomes of different companies and their final results, according evaluated by EVA (Economic Value Added). The growth implementation, for any company, into an organization, is always a polemical decision. There are several different aspects, which guide the decision of how and how much might be this growth, that must be taken into account by the company managers, in order to, by means of a well designed planning, this company could develop its activities into a less turbulent environment, this way avoiding troubles and other unexpected circumstances that may emerge when strategical decisions are made without the due cares and planning. Along this study, is made a discussion upon several techniques used for measuring results on companies. Particularly, it is analyzed the EVA index, which was the selected tool for measuring the results of the selected companies. Besides, are also pointed out the result measuring models described by Michel Fleuriet and by Dante Matarazzo. The main question, in this study, is: “Are the final results of companies impacted by their income growths?”. As the main objective of the work, it was established that should be analyzed the relationship between the result of a company, evaluated by the EVA index, and the income growth of this company. Besides, as secondary objectives, were selected: to analyze on which form the best result companies compose their resource fonts, and to analyze which is the correlation between the final result and the annual income growth, and the internal growth rate, and the sustainable growth rate. The effected analysis, from a sample of the results of 34 companies, demonstrated that, for the estimated hypothesis, it may be stated that this correlation, if existing, is weak. In other words, for the examined sample, the correlation between the income growth and the final result is low.
135

Análise de desempenho de estrutura de pavimento flexível da rodovia BR-290/RS no trecho Osório-Porto Alegre

Vitorello, Thiago January 2008 (has links)
Os modelos de previsão de desempenho são ferramentas fundamentais em um Sistema de Gerência de Pavimentos. Embora de grande importância, especificamente no Brasil, tem-se dado pouca atenção para a calibração e validação desses modelos. Acaba-se adotando modelos genéricos, obtidos em condições totalmente diferentes das existentes na malha administrada. Para uma gerência correta dos pavimentos de uma rodovia, torna-se fundamental a definição de modelos representativos das condições estruturais e funcionais dos pavimentos administrados. Esta pesquisa tem como objetivo avaliar o desempenho de uma estrutura de pavimento flexível da rodovia BR-290/RS, desenvolvendo, a partir dessa avaliação, modelos que representem a tendência do comportamento do pavimento. A rodovia BR-290/RS está, no trecho entre as cidades de Osório e Porto Alegre, sob concessão da Concessionária da Rodovia Osório - Porto Alegre S/A - Concepa, desde o ano de 1997. Uma das principais ações a serem realizadas pela concessionária no período em que este trecho da rodovia está sob sua administração é a execução do alargamento das pistas da mesma, com a construção de uma nova estrutura de pavimento junto à plataforma existente, sendo essa a estrutura de pavimento analisada nesta pesquisa. A estrutura contempla 8cm de revestimento asfáltico, 15cm de base, 30cm de sub-base e 60cm de camada de reforço. Os pavimentos inseridos na análise foram construídos entre os anos 2000 e 2007. Para atingir o objetivo da pesquisa, foram reunidas informações obtidas em levantamentos de deflexões, irregularidade longitudinal e afundamento de trilha de roda realizados nos últimos anos. As deflexões foram determinadas em levantamento com o equipamento FWD ocorrido em 2007. A irregularidade longitudinal e o afundamento de trilha de roda foram obtidos simultaneamente em levantamentos com o perfilômetro a laser nos anos 2005, 2006 e 2007. De posse dessas informações, analisou-se o comportamento de tais parâmetros com a ação do tráfego, desenvolvendo tendências de desempenho para a estrutura. Na análise considerou-se a influência das intervenções ocorridas nos pavimentos após a sua construção, bem como diferentes procedimentos adotados nos levantamentos realizados. Em relação às intervenções, verificou-se que, para a estrutura e dados do estudo, elas foram influentes apenas na evolução da irregularidade longitudinal. Análises estatísticas foram efetuadas, de modo a definir o melhor ajuste para cada parâmetro. Após o desenvolvimento de tais tendências de comportamento do pavimento, as mesmas foram comparadas aos modelos de previsão de desempenho desenvolvidos em outras pesquisas. Para a irregularidade e o afundamento de trilha de roda, as tendências apresentadas neste estudo comportaram-se significativamente semelhantes as de outros modelos encontrados na bibliografia técnica. Por outro lado, para a tendência referente às deflexões, nenhum dos modelos desenvolvidos em estudos anteriores apresentou comportamento similar ao encontrado na pesquisa, evidenciando a importância do desenvolvimento de modelos particulares para cada rodovia e estrutura. / Pavement performance prediction models are important tools for pavement management systems. Despite its high importance, specifically in Brazil, little attention has been given to calibration and validation of such models. Generic models are eventually used, even international ones, obtained for rather different conditions of those valid for the managed network. Hence, it is vital for an appropriate road pavement management that representative models of the structural and functional conditions of the associated pavements are defined. This research aims to evaluate the behaviour of the performance of a flexible pavement section of the road BR-290/RS, developing from this assessment, models that are representative of the pavement behaviour tendency. The road BR-290/RS is located between the cities of Osório and Porto Alegre, under concession of Concessionária da Rodovia Osório - Porto Alegre S/A - Concepa, since the year of 1997. One of the main actions to be accomplished by the road concessionary within the period under its administration is the carriageway widening of this road with the construction of a new pavement structure alongside, being this structure the objective of study in this research. The structure consists of an asphaltic layer of 8cm, 15cm of base course, 30cm of sub-base and 60cm of a capping layer. The pavement segments included in the analysis were built between 2000 and 2007. To deliver the objectives of this research, data obtained in deflectometric test campaigns, longitudinal roughness and rutting testing campaigns were gathered. Deflections were assessed in the FWD test campaign of 2007. Longitudinal roughness and rutting were simultaneously obtained with a laser profilometer in tests carried out in the years of 2005, 2006 and 2007. With this data, the behaviour of these parameters were evaluated with the traffic evolution, allowing the development of behaviour tendencies of this structure performance to be derived. In the analysis, the influence of the interventions carried out in the pavement sections after its construction were taken into account, as well as different procedures adopted in the testing campaigns carried out. In regard to the interventions, it was observed that, for the data and structure object of this study, they only had effect in the longitudinal roughness evolution. Statistical analyses were carried out in order to define the best adjustment to each parameter. After the development of such tendencies on the pavement behaviour, they were compared to pavement performance prediction models developed in other researches. For both roughness and rutting, the tendencies presented in the study behaved significantly as the other models found in the technical literature. As to the tendencies regarding deflections, none of the models developed in previous studies evidenced similar behaviour to the one observed in this research, testifying the importance for the development of particular models for each road and structure.
136

Análise estatística R-Modal, Q-Modal e Cluster no estudo da qualidade da água subterrânea do aquífero Jandaíra na Chapada do Apodi / Statistical analysis R-modal, Q-modal and Cluster in the study of the quality of groundwater aquifer Jandaíra in the Apodi Plateau

Granjeiro, Michel Lopes January 2012 (has links)
GRANJEIRO, Michel Lopes. Análise estatística R-Modal, Q-Modal e Cluster no estudo da qualidade da água subterrânea do aquífero Jandaíra na Chapada do Apodi. 2012. 118 f. Tese (Doutorado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2012. / Submitted by Edvander Pires (edvanderpires@gmail.com) on 2015-05-29T20:14:33Z No. of bitstreams: 1 2012_tese_mlgranjeiro.pdf: 2308619 bytes, checksum: 27af20ae427c0f1e4fe5560ed9c7320a (MD5) / Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2015-05-29T20:23:01Z (GMT) No. of bitstreams: 1 2012_tese_mlgranjeiro.pdf: 2308619 bytes, checksum: 27af20ae427c0f1e4fe5560ed9c7320a (MD5) / Made available in DSpace on 2015-05-29T20:23:01Z (GMT). No. of bitstreams: 1 2012_tese_mlgranjeiro.pdf: 2308619 bytes, checksum: 27af20ae427c0f1e4fe5560ed9c7320a (MD5) Previous issue date: 2012 / Analyses of 15 hydrochemical parameters in groundwater from the Jandaíra aquifer of the Potiguar Basin were performed on two sets of wells, one with 97 wells sampled in the dry season and the other one with 80 wells sampled at the beginning of the rainy season. The wells are located in the townships of Baraúna and Mossoró, in the State of Rio Grande do Norte, and in Jaguaruana, Quixeré, and Limoeiro do Norte, in the State of Ceará. Statistical treatment of data from each sampling applying R-modal Factor Analysis allowed to identify the processes responsible for the presence of minerals in the waters. During the dry season, Factor 1 indicates the importance of marine aerosol, mainly through the concentrations of chloride and sodium, and lithologocal influence through hardness. Factor 2 indicates dissolution of limestone, evidenced by the presence of bicarbonate and pH. In the rainy season, Factor 1 also reflects the influence of aerosol and hardness, but Factor 2 considers bicarbonate only, indicating recharge to the aquifer. In both simulations, the predominance of a single variable in the other factors indicates mixing of different water types and also reveals slight human impact. Q-modal Analysis done with all wells indicates as the group best correlated the wells of Baraúna, represented by Factor 1, followed by wells of Mossoró, represented by Factor 2. Cluster Analysis complemented Q-modal Analysis and allows to associate wells in groups, indicating a hydraulic connection between them or recharge through similar water. This analysis reveals equivalence between the First Group and Factor 1 of Q-modal Analysis and of the Second Group and Factor 2 of Q-modal Analysis. The First and Second Groups comprise more wells in the dry season than in the rainy one, when recharge contributes to mixing with water of different composition than that in the aquifer. / Análise de 15 parâmetros hidroquímicos em águas subterrâneas do aquífero Jandaíra, na Bacia Potiguar, foi realizada em dois conjuntos de poços amostrados, o primeiro com 97 amostras no período seco e o segundo com 80 no início do período chuvoso. Os poços estão localizados nos municípios de Baraúna e Mossoró, no Estado do Rio Grande do Norte e nos municípios de Jaguaruana, Quixeré e Limoeiro do Norte, no Estado do Ceará. O tratamento estatístico dos dados de cada coleta feito com a Análise Fatorial R-modal permitiu identificar os processos responsáveis pela presença dos sais nas águas. No período seco, o Fator 1 indicou a importância dos aerossóis de origem marinha, principalmente pelas concentrações de cloretos e de sódio, e a influência litológica pela dureza. O Fator 2 indicou dissolução de rochas calcárias, mostrada pela presença do bicarbonato e do pH. No período chuvoso, o Fator 1 também reflete a influência dos aerossóis e da dureza, mas o Fator 2 considera somente o bicarbonato, indicando recarga no aqüífero. Nas duas simulações, o domínio de uma única variável nos outros fatores indica mistura de diferentes tipos de água e revela uma leve ação antrópica. A Análise Q-modal feita com todos os poços, indicou como grupo melhor correlacionado o dos poços do município de Baraúna, representado pelo Fator 1, seguido pelos poços de Mossoró, representados pelo Fator 2. A Análise Cluster complementou a Análise Q-modal e permitiu associar os poços em grupos, indicando uma conectividade entre eles ou uma recarga por água semelhante. Essa análise mostrou equivalência entre o Primeiro Grupo e o Fator 1 da Análise Q-modal e o Segundo Grupo e o Fator 2 da Análise Q-modal. O Primeiro e o Segundo Grupo têm mais poços no período seco do que no chuvoso quando a recarga contribui para mistura com água de composição diferente da água do aquífero.
137

Étude métrologique de solutions ioniques par spectrométrie Raman et analyses statistiques / Metrological study of ionic solutions by Raman spectrometry and statistical analysis

Kauffmann, Thomas H. 12 December 2016 (has links)
L’objectif de ce travail de recherche est d’étudier la possibilité d’utiliser la spectrométrie Raman dite "conventionnelle" pour l’analyse, voire le contrôle in situ de solutions ioniques et d'en déterminer les limites. Nous avons étudié différentes solutions salines, composées d'ions polyatomiques comme le nitrate (NO3-) donnant des raies Raman autour de 1000 cm-1, et d'ions halogénures (F-, Cl-, Br-, I-) qui ne possèdent pas de signature directe mais influencent de manière indirecte le spectre de l’eau. Les méthodologies proposées dans ce travail permettent une identification et une quantification des solutions salines et sont basées sur des analyses classiques de spectres à l'aide de pré-traitements (normalisation, correction de ligne de base). Les limites de détection des ions étudiés correspondent pour certains ions aux limites de potabilité de l’eau (nitrates et sulfates par exemple). D’autres substances restent impossibles à quantifier (nitrite, ammonium). Des méthodes statistiques ont ensuite été employées. Ainsi, l’analyse en composante principale (ACP) permet d’identifier la nature d’une solution saline, que l’ion présente une signature directe ou indirecte, et d'accéder aux arrangements moléculaires des ions avec l’eau. La régression PLS permet de quantifier les ions en solution à travers des modèles de prédiction. Cette méthode a été utilisée sur des solutions pures de nitrate et de chlorure avec des erreurs sur les prédictions en concentration 4 à 5 fois plus faibles que celles trouvées par les méthodes classiques. Ces méthodes statistiques ont également permis de descendre à des gammes de concentrations en ion Cl- beaucoup plus faibles (10-100 mM) / The objective of this research is to study the possibility of using conventional Raman spectroscopy for analysis, or in situ control of substances dissolved in water and to determine the limits of this technique. Several salt solutions were studied. Polyatomic ions such as nitrate (NO3-) give intense Raman lines around 1000 cm-1. Halide ions (F-, Cl-, Br-, I-) have no direct signature but indirectly affect the water spectrum. The methodology proposed in this work for identification and quantification of salt solutions is based on classical analysis of spectra using pre-treatment methods (normalization, baseline correction). The limits of detection of the studied ions correspond to the water potability limits. It is possible to go below the potability limits for nitrates and sulfates for example but it is impossible to reach them for some other substances (nitrite, ammonium). Then, statistical methods were used. Thus, the principal component analysis (PCA) allows to identify the nature of a salt solution (with direct or indirect signatures) and to acces to the molecular arrangements of ions with water. PLS regression quantifies the ions through predictive models. This method was used on pure solutions of nitrate and chloride with errors on the concentration predictions 4 to 5 times lower than those found by classical methods. Lower concentration ranges (10-100 mM) for the Cl- ion are reachable using these statistical methods
138

Avaliação dos aspectos texturais na imagem Landsat como subsídio à compartimentação fisiográfica dos municípios de Peruíbe e Itanhaém - SP

Moreira, Mirley Ribeiro [UNESP] January 2003 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2003Bitstream added on 2014-06-13T18:54:15Z : No. of bitstreams: 1 moreira_mr_me_rcla.pdf: 4230931 bytes, checksum: d03e922a64150ccc7e14429414e1555c (MD5) / As imagens de satélite, por serem um registro de alvos com diferentes comportamentos espectrais e diferentes arranjos espaciais, respondem com variações tonais de cinza e variações texturais. Esta variação textural é analisada normalmente através de interpretação visual, que é uma sistematização de várias técnicas, as quais convergem para um único objetivo, a compartimentação da imagem. Em geral, a textura apresenta-se como sendo uma arma valiosa na interpretação de formas de relevo, drenagem e de padrões da cobertura vegetal e de uso da terra. Acredita-se que, a partir da utilização das técnicas de processamento digital de imagens e técnicas estatísticas multivariadas, como subsidiária na redução do caráter subjetivo da análise textural e da correspondência entre zonas homólogas, será possível favorecer a discriminação de elementos imageados, e encontrar um modelo que possibilite explicar mais satisfatoriamente a compartimentação e a relação de equivalência entre zonas que constituem texturas semelhantes. Desta forma, o objetivo geral do trabalho, é avaliar diversas metodologias, com intuito de realizar uma compartimentação fisiográfica, explorando o aspecto textural da imagem além da similaridade existentes entre as áreas após compartimentada. A área de estudo abrange os municípios de Itanhaém e Peruíbe localizados no litoral sul do Estado de São Paulo. A partir dos resultados obtidos, verificou-se que o método convencional de fotointerpretação juntamente com a aplicação da análise estatística multivariada, mostrou-se viável de ser aplicado apresentando resultados satisfatórios e inovadores. Já no processamento de alguns algoritmos de textura a redução de informações foi bastante grande, devido à redução dos valores de níveis de cinza e à homogeneização dos alvos; mostrando que o resultados não foram positivos... / Satellite images record surface features based on their different spectral behaviors and spatial arrangements. As such, these features are discernable from different shades of gray and textural variations seen in the images. These textural variations represent a systematic utilization of various techniques, which converge for a single objective: compartmentalization of the image. In general, texture is used as an important tool in the interpretation of relief forms, drainage patterns and vegetative cover and land-use patterns. Through the application of digital processing techniques and multivariable statistical analyses, it is possible to reduce the subjective character of textural analysis and correspondence between homologous zones, hence enhance the discrimination of different elements in an image. These methods can help find a model that allows for a better explanation of the compartmentalization and equivalence between zones that consist of similar textures. In this form, the general objective of the study is to evaluate diverse methodologies with the objective of determining the physiographic compartmentalization, exploiting the textural aspect of the image in addition to the existing similarities between areas following compartmentalization. The study area is within the municipalities of Itanhaém e Peruíbe, located along the south coastal region of São Paulo State. Based on the results obtained, it is confirmed that the conventional method of photo-interpretation, together with the application of multivariate statistical analysis, shows that it is a viable combination, yielding both satisfactory and innovative results. Already, in the processing of some textural algorithms, the reduction of information was significant, owing to the reduction of the values in the shades of gray and to the homogenization of targets, showing that the results were not positive...(Complete abstract click electronic access below)
139

Electron beam diagnosis for weld quality assurance

Kaur, Aman P. January 2016 (has links)
Electron beam welding is used for fabricating critical components for the aerospace and nuclear industries which demand high quality. The cost of materials and associated processes of fabrication is also very high. Therefore, manufacturing processes in these industries are highly controlled. However, it has been found that even minor changes in the electron beam gun itself can produce large variations in beam characteristics, leading to unpredictable welding performance. Hence, it is very important to ensure the beam quality prior to carrying out welds. This requires some kind of device and process to characterise the electron beam to indicate variations. A detailed review of different technologies used to develop devices to characterise electron beams has been carried out. At this time, it is uncommon for beam measurement to be carried out on production EBW equipment. Research carried out for this thesis is focused on development of a novel approach to characterise the electron beams using a slit-probe to maintain the quality of the welds. The challenge lies in deriving relevant features from the acquired probe signal which can effectively differentiate between the beams of different quality. Wavelet transformation, with its advantages over other methods for simultaneous time and frequency localization of signals, has found its application to feature extraction in many pattern based classifications. This technique has been used to analyse probe signals considering that different quality beams will possess unique signal profiles in the form of their distribution of energies with respect to frequency and time. To achieve the aim of the thesis, an experimental approach was used by carrying out melt runs on Ti-6Al-4V plates focusing on aerospace requirements, and varying beam properties and acquiring probe signals for all beam settings. Extracted features from the probe signals have been used in classification of the electron beams to ensure these will produce welds within the tolerance limits specified by aerospace standards for quality assurance. The features vector was compiled following statistical analysis to find the significant beam characteristics. By analysing the performance of classifier for different combination of parameters of the features vector, the optimum classification rate of 89.8% was achieved by using the parameters derived from wavelet coefficients for different decomposition levels. This work showed that the use of wavelet analysis and classification using features vectors enabled identification of beams that would produce welds out-of-tolerance. Keywords: Electron beam welding, probe devices, electron beam characterisation, quality assurance, wavelet transform, features vector, linear discriminant classifier, weld profiles, weld defects.
140

Análise de desempenho de estrutura de pavimento flexível da rodovia BR-290/RS no trecho Osório-Porto Alegre

Vitorello, Thiago January 2008 (has links)
Os modelos de previsão de desempenho são ferramentas fundamentais em um Sistema de Gerência de Pavimentos. Embora de grande importância, especificamente no Brasil, tem-se dado pouca atenção para a calibração e validação desses modelos. Acaba-se adotando modelos genéricos, obtidos em condições totalmente diferentes das existentes na malha administrada. Para uma gerência correta dos pavimentos de uma rodovia, torna-se fundamental a definição de modelos representativos das condições estruturais e funcionais dos pavimentos administrados. Esta pesquisa tem como objetivo avaliar o desempenho de uma estrutura de pavimento flexível da rodovia BR-290/RS, desenvolvendo, a partir dessa avaliação, modelos que representem a tendência do comportamento do pavimento. A rodovia BR-290/RS está, no trecho entre as cidades de Osório e Porto Alegre, sob concessão da Concessionária da Rodovia Osório - Porto Alegre S/A - Concepa, desde o ano de 1997. Uma das principais ações a serem realizadas pela concessionária no período em que este trecho da rodovia está sob sua administração é a execução do alargamento das pistas da mesma, com a construção de uma nova estrutura de pavimento junto à plataforma existente, sendo essa a estrutura de pavimento analisada nesta pesquisa. A estrutura contempla 8cm de revestimento asfáltico, 15cm de base, 30cm de sub-base e 60cm de camada de reforço. Os pavimentos inseridos na análise foram construídos entre os anos 2000 e 2007. Para atingir o objetivo da pesquisa, foram reunidas informações obtidas em levantamentos de deflexões, irregularidade longitudinal e afundamento de trilha de roda realizados nos últimos anos. As deflexões foram determinadas em levantamento com o equipamento FWD ocorrido em 2007. A irregularidade longitudinal e o afundamento de trilha de roda foram obtidos simultaneamente em levantamentos com o perfilômetro a laser nos anos 2005, 2006 e 2007. De posse dessas informações, analisou-se o comportamento de tais parâmetros com a ação do tráfego, desenvolvendo tendências de desempenho para a estrutura. Na análise considerou-se a influência das intervenções ocorridas nos pavimentos após a sua construção, bem como diferentes procedimentos adotados nos levantamentos realizados. Em relação às intervenções, verificou-se que, para a estrutura e dados do estudo, elas foram influentes apenas na evolução da irregularidade longitudinal. Análises estatísticas foram efetuadas, de modo a definir o melhor ajuste para cada parâmetro. Após o desenvolvimento de tais tendências de comportamento do pavimento, as mesmas foram comparadas aos modelos de previsão de desempenho desenvolvidos em outras pesquisas. Para a irregularidade e o afundamento de trilha de roda, as tendências apresentadas neste estudo comportaram-se significativamente semelhantes as de outros modelos encontrados na bibliografia técnica. Por outro lado, para a tendência referente às deflexões, nenhum dos modelos desenvolvidos em estudos anteriores apresentou comportamento similar ao encontrado na pesquisa, evidenciando a importância do desenvolvimento de modelos particulares para cada rodovia e estrutura. / Pavement performance prediction models are important tools for pavement management systems. Despite its high importance, specifically in Brazil, little attention has been given to calibration and validation of such models. Generic models are eventually used, even international ones, obtained for rather different conditions of those valid for the managed network. Hence, it is vital for an appropriate road pavement management that representative models of the structural and functional conditions of the associated pavements are defined. This research aims to evaluate the behaviour of the performance of a flexible pavement section of the road BR-290/RS, developing from this assessment, models that are representative of the pavement behaviour tendency. The road BR-290/RS is located between the cities of Osório and Porto Alegre, under concession of Concessionária da Rodovia Osório - Porto Alegre S/A - Concepa, since the year of 1997. One of the main actions to be accomplished by the road concessionary within the period under its administration is the carriageway widening of this road with the construction of a new pavement structure alongside, being this structure the objective of study in this research. The structure consists of an asphaltic layer of 8cm, 15cm of base course, 30cm of sub-base and 60cm of a capping layer. The pavement segments included in the analysis were built between 2000 and 2007. To deliver the objectives of this research, data obtained in deflectometric test campaigns, longitudinal roughness and rutting testing campaigns were gathered. Deflections were assessed in the FWD test campaign of 2007. Longitudinal roughness and rutting were simultaneously obtained with a laser profilometer in tests carried out in the years of 2005, 2006 and 2007. With this data, the behaviour of these parameters were evaluated with the traffic evolution, allowing the development of behaviour tendencies of this structure performance to be derived. In the analysis, the influence of the interventions carried out in the pavement sections after its construction were taken into account, as well as different procedures adopted in the testing campaigns carried out. In regard to the interventions, it was observed that, for the data and structure object of this study, they only had effect in the longitudinal roughness evolution. Statistical analyses were carried out in order to define the best adjustment to each parameter. After the development of such tendencies on the pavement behaviour, they were compared to pavement performance prediction models developed in other researches. For both roughness and rutting, the tendencies presented in the study behaved significantly as the other models found in the technical literature. As to the tendencies regarding deflections, none of the models developed in previous studies evidenced similar behaviour to the one observed in this research, testifying the importance for the development of particular models for each road and structure.

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