• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 45
  • 16
  • 14
  • 9
  • 9
  • 8
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 120
  • 39
  • 28
  • 23
  • 23
  • 22
  • 16
  • 15
  • 13
  • 13
  • 12
  • 11
  • 11
  • 10
  • 10
  • 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.
61

Underhåll av en cementbultsättare : En analys för att öka tillgängligheten

Pittja, Aminda January 2022 (has links)
I samband med allt hårdare krav ställs på hög kvalitet och snabba leveranstider i produktioner har även kraven för tillgänglighet hos enheter och maskiner ökat i större industriprocesser. Utvecklingen av underhållstekniska lösningar och tillvägagångssätt har gjort det möjligt att mäta, analysera och identifiera kritiska delar i produktioner. Målet med att underhålla är att upprätthålla en enhet eller maskin till ett sådan tillstånds som krävs för att nå de övergripande målsättningar ett företag har för att förebygga att oplanerade stopp, haverier eller fel som hindrar företaget att nå sitt mål. Syftet med detta arbete är att ta fram en underhållsplan som ökar tillgängligheten hos en cementbultsättare som utför bergförstärkande åtgärder i en underjordsgruva. Analysen genomförs på ett systematiskt sätt för att utreda vilka delar hos en bergbultsrigg, cementbultsättare som i nuläget orsakar flest oplanerade stopp och rikta åtgärder till dessa delar. I arbetet presenteras underhållsstrategier som kan tillämpas för målsättningen att öka tillgängligheten och vidare diskuteras metoder för att bedriva en underhållsverksamhet i enlighet med RCM.
62

Combustion Characteristics of Moist H2 and H2/CO Mixtures and In-situ Temperature and Species Measurements Using Mid-IR Absorption Spectroscopy in a New RCM

Das, Apurba K. 22 May 2012 (has links)
No description available.
63

EXAMINATION OF GRADING PATTERNS DURING ONE INSTITUTION’S TRANSITION TO A RESPONSIBILITY CENTER MANAGEMENT BUDGET MODEL

Reiter, Jonathan, 0000-0002-1142-1818 05 1900 (has links)
This study examines grading patterns during one intuition’s transition to a responsibility center management (RCM) budget model. RCM is intended to focus an institution on resource growth and cost control, and the model incentivizes and rewards these behaviors. The adoption of RCM is becoming more widespread across the United States, especially as institutions are experiencing declining enrollment and shrinking state support (Barr & McClellan, 2018; State Higher Education Executive Officers Association [SHEEO], 2021; The Pew Charitable Trusts, 2019). This has led to budget management being cited as a top priority for institutional leaders (Bass et al., 2021; Rylee, 2011). This decline in enrollment and shrinking state support makes institutions more reliant on existing and prospective students as their primary source of revenue. Through the lens of Resource Dependency Theory (RDT) it is reasonable to assume that institutions may engage in behaviors and practices to maximize their relationship with students. Moreover, as students continue to see themselves as consumers who deserve high grades and a degree, institutions have changed their grading practices to attract and retain these students, and research has shown that students take advantage of these practices to protect their GPA (Bromley et al., 1978; Goldman, 1985). Additionally, research has shown that students, in part, make course choices based on difficulty and expected grade (e.g., Barr et al., 2009; Butcher et al., 2014; Fournier & Sass, 2000; Sabot & Wakemin-Linn, 1991). Therefore, it is reasonable to hypothesize that institutions may transition to RCM to focus on resource growth, and given their reliance on student enrollment, may engage in practices and behaviors to maximize the relationship between the institution and the student. These actions may have unintended consequences, such as grade inflation. My study begins to examine if grade inflation is an unintended consequence of a transition to RCM by exploring what happened to grades during one institution’s transition to RCM. The results of my study show that at Public Research University (PRU), a pseudonym, grades continued to increase during and after the implementation of RCM, with a statistically significant increase occurring in the year immediately following PRU’s “hold harmless” year. My results also show that grades continued to rise during and after PRU’s transition to RCM across all departments when categorized based on historical GPAs, selectivity levels, and enrollment levels. This study is intended to raise awareness of the far-reaching effects that central university decisions, such as budget model choice, may have across the entire institution – both intended and unintended. / Educational Leadership
64

Synthèse et Etude d'Analogues Peptidiques en tant qu'Inhibiteurs de Fusion du VIH / Synthesis and Study of Peptide analogs as HIV Fusion Inhibitors

Baron, Alice 15 December 2010 (has links)
Depuis la découverte du Virus de l'Immunodéficience Humaine (VIH) au début des années 80, la recherche de nouvelles molécules anti-VIH demeure un challenge important pour la communauté scientifique. Les effets secondaires liés à l'usage d'inhibiteurs de la réplication virale, la découverte des récepteurs et la compréhension du mécanisme d'entrée du virus dans la cellule hôte ont encouragé la recherche sur de nouveaux inhibiteurs ciblant l'entrée virale. A ce jour, l'Enfuvirtide est le seul inhibiteur d'entrée approuvé en tant qu'inhibiteur de fusion. Bien que ce composé soit un antiviral puissant, il présente néanmoins de sérieuses limitations, son mode d'administration (injection sous cutanée deux fois par jour) et l'émergence de résistances, le classent en agent rétroviral de seconde classe. Une approche alternative est la génération de D-peptides inhibiteurs de fusion, résistants aux protéases et prometteurs pour le développement et l'identification d'une nouvelle classe de médicaments anti-VIH. Basée sur cette dernière approche, cette thèse est consacrée à la synthèse et à l'étude d'analogues peptidiques en tant qu'inhibiteurs de fusion du VIH. Tout d'abord, des études de modélisation associées à la synthèse d'analogues peptidiques ont permis de mettre en évidence et de comprendre les caractéristiques essentielles responsables de l'activité des D-peptides. Ensuite, des études de relations structure-activité, à partir de séquences modifiées, ont conduit à l'obtention de nouveaux analogues peptidiques inhibiteurs de fusion actifs. Enfin, dans le but de réduire la nature peptidique et par conséquent d'améliorer les propriétés pharmaceutiques, des macrocycles peptidiques ont été conçus, et une nouvelle stratégie de synthèse de peptides cycliques a été développée. / Since the discovery of the Human Immunodeficiency Virus (HIV) at the beginning of the 1980's, the search for new anti-HIV molecules remains an important challenge for the scientific community. Secondary effects associated with viral replication inhibitors, the discovery of receptors and the understanding of the mechanism of the viral entry makes HIV viral entry one of the most promising target for HIV drug development. To date, Enfurvitide is the only approved entry inhibitor as HIV fusion inhibitor. Although highly effective, Enfurvirtide has several serious limitations including high dosing requirements, the administration by injection, and the emergence of resistant strains. An alternative approach that has shown considerable potential is the generation of new D-peptides HIV fusion inhibitors expected to be resistant to proteolytic degradation and useful for the development and the identification of a new class of anti-HIV drugs with improv ed bioavailability.Based on this approach, the present work is dedicated to the synthesis and the study of peptide analogs as HIV fusion inhibitors. First, modeling studies and the synthesis of peptide analogs were devoted to point out and to understand the key elements responsible for the activity of the reference D-peptides. Then, structure activity relationship studies based on different modifications sequences led to the discovery of active peptide analogues as HIV fusion inhibitors. In another approach, in order to decrease peptide nature and consequently to improve the pharmaceutical properties, reduced cyclic peptides were designed. Finally, a novel strategy for cyclic peptide synthesis was developed.
65

Étude de réactivité et de sélectivité de nouveaux catalyseurs à base de ruthénium

Stenne, Brice 08 1900 (has links)
Ce projet de recherche consiste en l’étude de la réactivité et de la sélectivité de nouveaux catalyseurs de métathèse d’oléfines à base de ruthénium lors de réaction de fermeture de cycle par métathèse d’oléfines (RCM). L’emphase de cette étude repose sur l’évaluation de nouveaux catalyseurs possédant un ligand NHC (carbène N-hétérocyclique) C1-symétrique développés par le laboratoire Collins pour des réactions de désymétrisations asymétriques de méso-triènes par ARCM. Le projet a été séparé en deux sections distinctes. La première section concerne la formation d’oléfines trisubstituées par ARCM de méso-triènes. La seconde section consiste en la formation d’oléfines tétrasubstituées par le biais de la RCM de diènes et de la ARCM de méso-triènes. Il est à noter qu’il n’y a aucun précédent dans la littérature concernant la formation d’oléfines tétrasubstituées suite à une désymétrisation par ARCM. Lors de l’étude concernant la formation d’oléfines trisubstituées, une étude de cinétique a été entreprise dans le but de mieux comprendre la réactivité des différents catalyseurs. Il a été possible d’observer que le groupement N-alkyle a une grande influence sur la réactivité du catalyseur. Une étude de sélectivité a ensuite été entreprise pour déterminer si le groupement N-alkyle génère aussi un effet sur la sélectivité des catalyseurs. Cette étude a été effectuée par l’entremise de réactions de désymétrisation d’une variété de méso-triènes. En ce qui a trait à la formation d’oléfines tétrasubstituées, une étude de la réactivité des différents catalyseurs a été effectuée par l’intermédiaire de malonates de diéthyldiméthallyle. Il a encore une fois a été possible d’observer que le groupement N-alkyle possède un effet important sur la réactivité du catalyseur. Une étude de sélectivité a ensuite été entreprise pour déterminer si le groupement iv N-alkyle génère aussi un effet sur la sélectivité des catalyseurs. Cette étude a été effectuée par l’entremise de réactions de désymétrisation de différents mésotriènes. / This research consists in the study of the reactivity and selectivity of new chiral Ru-based olefin metathesis catalysts in ring-closing metathesis (RCM) reactions. The study focused on evaluating new catalysts possessing C1- symmetric NHC (N-heterocyclic carbene) ligands developed in our laboratories for asymmetric desymmetrization reactions of meso-trienes. The research was divided into two distinct sections, the first concerns the asymmetric ring closing metathesis (ARCM) processes that form trisubstituted olefins from meso-trienes. The second concerns the RCM and ARCM processes that form tetrasubstituted olefins from meso-trienes. It can be observed that there is no precedent in the literature concerning the formation of tetrasubstituted olefins via ARCM. During the investigation concerning the formation of trisubstituted olefins, a kinetic study was done to have better understanding of the catalyst selectivity. With this study in hand, it was possible to observe the effect induced by the N-alkyl group on the catalysts’ reactivity. A selectivity study was done to observe if the Nalkyl group could affects the catalysts’ selectivity. These investigations were done using a variety of meso-trienes in desymmetrization reactions to afford trisubstituted olefins. Concerning the formation of tetrasubstituted olefins, the catalysts’ reactivity was investigated in RCM processes involving diethyldimethallyl malonates. Once again, an effect induced by the N-alkyl group was observed concerning the reactivity of the catalysts. A selectivity study was performed. As for ARCM processes forming trisubstituted olefins, the N-alkyl group also had an impact on the selectivity of the catalysts. This investigation was done with ARCM desymmetrization of meso-trienes.
66

Utredning av stopptider i ett täcklacksmåleri verksamt inom fordonsindustrin

Andersson, Hilda, Nygren Gustafsson, Lina January 2019 (has links)
The purpose of this study is to investigate and analyze stops that occur in the painting process of trucks; specifically related to the buffer system after the top coat process. Based on this investigation, improvements are presented in order to eliminate stops and improve overall assembly time. With this scope in mind, the following issues have been raised:   1.     What are the root causes for stops in the buffer system? 2.     How much can corrective maintenance be reduced? 3.     What potential savings are achieved by reducing or eliminating stops in the buffer system? 4.     How would reducing stops increase the availability for the top coat paint shop?   A case study has been performed where historical data has been analyzed and staff from the production, maintenance and IT departments have been interviewed. The analyzed data along with a theoretical framework are the basis for the suggested actions that will improve flows through the top coat production. The result indicates that a great part of the delays related to the buffer system are caused by soft losses. The stops are the results of: Lack of a distinct set of rules for how data and software may be used Lack of communication between the workshops The implications of these delays are: increased costs and reduced efficiency of the production line. The purposed actions presented in the study gives the company opportunity to achieve full capacity, eliminate delays and increase overall efficiency. The study is limited to the top coat paint shop and does not include the primary paint shop or final assembly. The results, analysis and suggestions presented in the study includes the soft losses that causes stop in the buffer system. / Syftet med följande studie är att undersöka och analysera stopp och dess rotorsaker som uppkommer i buffertsystemet på ett täcklacksmåleri. Utifrån denna utredning presenteras sedan åtgärdsförslag i syfte att eliminera undersökta stopp. För att kunna uppfylla syftet med studien har följande frågeställningar formulerats:   Vad finns det för stopp relaterade till buffertsystemet och vad är rotorsakerna till dessa? Hur mycket kan det akuta underhållet reduceras? Hur stora besparingar skulle företaget kunna göra genom reducering eller eliminering av stoppen? På vilket sätt kan en minskning av stoppen öka tillgängligheten för täcklacksmåleriet?   En fallstudie har genomförts där historisk data har analyserats och personal från avdelningar som produktion, underhåll och IT har intervjuats. Den empiri som samlats in tillsammans med det teoretiska ramverket som presenteras i rapporten ligger till grund för resultatet, analysen och åtgärdsförslagen.   Resultatet från studien visar att en stor andel av de stopp som sker i buffertsystemet orsakas av mjuka förluster. Dessa stopp är en konsekvens av bristfällig hantering av data och mjukvara samt bristfällig kommunikation mellan verkstäderna. Konsekvenserna av dessa stopp resulterar i ökade kostnader samt en nedsatt effektivitet för täcklacksmåleriet. Åtgärdsförslagen som presenteras ger företaget goda möjligheter att uppnå sin fulla kapacitet, eliminera stoppen och därmed öka effektiviteten.   Studien är avgränsad till måleriprocessen och omfattas inte av grundmåleriet eller monteringen. De resultat, analyser och åtgärdsförslag som presenteras är avgränsade till de mjuka förlusterna som orsakar stopp i buffertsystemet.
67

Étude de réactivité et de sélectivité de nouveaux catalyseurs à base de ruthénium

Stenne, Brice 08 1900 (has links)
Ce projet de recherche consiste en l’étude de la réactivité et de la sélectivité de nouveaux catalyseurs de métathèse d’oléfines à base de ruthénium lors de réaction de fermeture de cycle par métathèse d’oléfines (RCM). L’emphase de cette étude repose sur l’évaluation de nouveaux catalyseurs possédant un ligand NHC (carbène N-hétérocyclique) C1-symétrique développés par le laboratoire Collins pour des réactions de désymétrisations asymétriques de méso-triènes par ARCM. Le projet a été séparé en deux sections distinctes. La première section concerne la formation d’oléfines trisubstituées par ARCM de méso-triènes. La seconde section consiste en la formation d’oléfines tétrasubstituées par le biais de la RCM de diènes et de la ARCM de méso-triènes. Il est à noter qu’il n’y a aucun précédent dans la littérature concernant la formation d’oléfines tétrasubstituées suite à une désymétrisation par ARCM. Lors de l’étude concernant la formation d’oléfines trisubstituées, une étude de cinétique a été entreprise dans le but de mieux comprendre la réactivité des différents catalyseurs. Il a été possible d’observer que le groupement N-alkyle a une grande influence sur la réactivité du catalyseur. Une étude de sélectivité a ensuite été entreprise pour déterminer si le groupement N-alkyle génère aussi un effet sur la sélectivité des catalyseurs. Cette étude a été effectuée par l’entremise de réactions de désymétrisation d’une variété de méso-triènes. En ce qui a trait à la formation d’oléfines tétrasubstituées, une étude de la réactivité des différents catalyseurs a été effectuée par l’intermédiaire de malonates de diéthyldiméthallyle. Il a encore une fois a été possible d’observer que le groupement N-alkyle possède un effet important sur la réactivité du catalyseur. Une étude de sélectivité a ensuite été entreprise pour déterminer si le groupement iv N-alkyle génère aussi un effet sur la sélectivité des catalyseurs. Cette étude a été effectuée par l’entremise de réactions de désymétrisation de différents mésotriènes. / This research consists in the study of the reactivity and selectivity of new chiral Ru-based olefin metathesis catalysts in ring-closing metathesis (RCM) reactions. The study focused on evaluating new catalysts possessing C1- symmetric NHC (N-heterocyclic carbene) ligands developed in our laboratories for asymmetric desymmetrization reactions of meso-trienes. The research was divided into two distinct sections, the first concerns the asymmetric ring closing metathesis (ARCM) processes that form trisubstituted olefins from meso-trienes. The second concerns the RCM and ARCM processes that form tetrasubstituted olefins from meso-trienes. It can be observed that there is no precedent in the literature concerning the formation of tetrasubstituted olefins via ARCM. During the investigation concerning the formation of trisubstituted olefins, a kinetic study was done to have better understanding of the catalyst selectivity. With this study in hand, it was possible to observe the effect induced by the N-alkyl group on the catalysts’ reactivity. A selectivity study was done to observe if the Nalkyl group could affects the catalysts’ selectivity. These investigations were done using a variety of meso-trienes in desymmetrization reactions to afford trisubstituted olefins. Concerning the formation of tetrasubstituted olefins, the catalysts’ reactivity was investigated in RCM processes involving diethyldimethallyl malonates. Once again, an effect induced by the N-alkyl group was observed concerning the reactivity of the catalysts. A selectivity study was performed. As for ARCM processes forming trisubstituted olefins, the N-alkyl group also had an impact on the selectivity of the catalysts. This investigation was done with ARCM desymmetrization of meso-trienes.
68

Aplicação da manutenção centrada em confiabilidade (RCM) na otimização do programa de manutenção de centrais termonucleares / Application of reliability-centred mainteinance in optimization of the nuclear power plants preventive maintenance program

Quintella, Luciano Confort [UNESP] 04 July 2016 (has links)
Submitted by LUCIANO CONFORT QUINTELLA null (l_quintella@yahoo.com.br) on 2016-08-16T18:29:05Z No. of bitstreams: 1 UNESP-FEG - Dissertação de Mestrado - APLICAÇÃO DA MANUTENÇÃO CENTRADA EM CONFIABILIDADE NA OTIMIZAÇÃO DO PROGRAMA DE MANUTENÇÃO DE CENTRAIS TERMONUCLEARES - Luciano C Quintella_Rev167 - REVISÃO FINAL.pdf: 5630978 bytes, checksum: 6d3c05b844c7ac7c30dd808f1c82303b (MD5) / Rejected by Ana Paula Grisoto (grisotoana@reitoria.unesp.br), reason: Solicitamos que realize uma nova submissão seguindo a orientação abaixo: O arquivo submetido não contém o certificado de aprovação assinado. A versão submetida por você é considerada a versão final da dissertação/tese, portanto não poderá ocorrer qualquer alteração em seu conteúdo após a aprovação. Corrija esta informação e realize uma nova submissão contendo o arquivo correto. Agradecemos a compreensão. on 2016-08-17T14:39:55Z (GMT) / Submitted by LUCIANO CONFORT QUINTELLA null (l_quintella@yahoo.com.br) on 2016-09-07T00:13:03Z No. of bitstreams: 1 UNESP-FEG - Dissertação de Mestrado - APLICAÇÃO DA MANUTENÇÃO CENTRADA EM CONFIABILIDADE NA OTIMIZAÇÃO DO PROGRAMA DE MANUTENÇÃO DE CENTRAIS TERMONUCLEARES - Luciano C Quintella_Rev168 - REVISÃO FINAL.pdf: 4453734 bytes, checksum: b3c4369bb61bf3c735292c7280dfc961 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-09-12T16:47:20Z (GMT) No. of bitstreams: 1 quintella_lc_me_bauru.pdf: 4453734 bytes, checksum: b3c4369bb61bf3c735292c7280dfc961 (MD5) / Made available in DSpace on 2016-09-12T16:47:20Z (GMT). No. of bitstreams: 1 quintella_lc_me_bauru.pdf: 4453734 bytes, checksum: b3c4369bb61bf3c735292c7280dfc961 (MD5) Previous issue date: 2016-07-04 / A função manutenção vem sendo considerada como fator estratégico para as empresas, pois através do alinhamento de suas políticas corporativas e integração de seus programas de gestão de ativos, de riscos e de ciclo de vida de suas unidades de negócios, as empresas vêm buscando a constante redução de custos e a melhoria de seus resultados operacionais. E, assim, obtendo maior competitividade. A Manutenção Centrada em Confiabilidade (RCM) é um método já bem disseminado por todo o mundo e que, ao longo dos anos, vem promovendo estes diferenciais estratégicos através de preceitos que possibilitam a elaboração de Programas de Manutenção Preventiva de custo-eficaz, através de um método para a definição de políticas de manutenção mais adequadas, com o foco na manutenção da função dos ativos em seu contexto operacional. Ao longo dos anos, o método RCM vem sendo aplicado em inúmeros estudos de casos em diferentes empresas de diversos seguimentos, onde podem ser observadas novas adaptações ou simplificações do método RCM clássico. Estas adaptações buscam uma maior adequação as particularidades destas empresas e/ou um retorno mais rápido de resultados. O setor nuclear de geração de energia foi um dos pioneiros na adoção e disseminação do RCM, e vem desenvolvendo processos simplificados de aplicação do RCM, como o “Streamlinned RCM” e o “método PMO” (Otimização do Programa de Manutenção, do inglês: Preventive Maintenance Optimization). Estes estudos mostram que o método PMO apresenta uma maior flexibilidade, o que permite a adoção de diferentes estratégias de aplicação que, por sua vez, têm trazido resultados expressivos para as empresas, através da otimização dos Programas de Manutenção já existentes. Com base na literatura, neste trabalho são abordadas questões referentes ao RCM e sua contextualização na área nuclear, estudos sobre os métodos simplificados do RCM e o desenvolvimento do método PMO. Por fim, é realizada uma aplicação prática do método PMO sobre os sistemas relacionados e subsistemas do Sistema de Remoção de Calor Residual (JN), mais especificamente, sobre as Bombas de injeção de segurança do Sistema de Injeção de Alta Pressão (JND) da Usina Nuclear Angra 2. Através dos resultados obtidos com esta aplicação, pretende-se otimizar o Programa de Manutenção da Planta (PMP) referente a estes equipamentos e, assim, validar o método PMO como ferramenta para a melhoria contínua do Programa de Gestão de Ativos e Ciclo de Vida da Usina Nuclear Angra 2. / Corporations tend to consider maintenance work a strategic element. It is through maintenance—especially the alignment between corporate policies and integration of their programs to manage assets, risks, and life cycles of business units—that corporations try to continuously improve their results, reduce their operational costs, and, therefore, increase their competitiveness. Reliability Centered Maintenance (RCM) is a popular method across the world; it has been promoting competitiveness through concepts that allow the design of cost-effective Preventive Maintenance Programs These programs are effective because they entail appropriate maintenance policies that are focused on the preservation of the assets functions in their operational context and on the formation of technical knowledge basis supported by hard data. Throughout the years, RCM has been applied in numerous case studies and in different companies engaged in a variety of market segments. Such diversity in the application of RCM allowed us to observe new adaptations and variations of the classic method. Such adaptations aim to better respond to specific operational contexts in and within production units, as well as achieve faster results. The nuclear power sector has pioneered regarding the adoption and dissemination of RCM; it has been developing simplified versions of RCM, such as the “Streamlined RCM” and the PMO (Preventive Maintenance Optimization). These studies demonstrate that the PMO presents enhanced flexibility, which allows the adoption of different strategies; such enhanced flexibility brings expressive results to corporations as pre-existing maintenance programs are optimized. Based on the currently available literature, this dissertation addresses numerous questions regarding RCM and its application to nuclear power segments. It also addresses studies about simplified versions of RCM and the development of the PMO method. The discussion is supplemented with a practical application of the PMO method regarding auxiliary systems and sub-systems of Removal of Residual Heat System (JN), especially those regarding the security injection pumps of the High Pressure Injection System (JND) at Angra II Nuclear Plant. Through the results obtained from this application, it is possible to optimize the Maintenance Program of these equipments, and therefore, validate the PMO method as a tool of continuous improvement of the Assets and Life Cycle Program of Angra II.
69

Análise comparativa de métodos de recuperação de emissividade com dados do infravermelho termal do sensor Aster

Becerra Rondón, Adriana Coromoto January 2017 (has links)
A emissividade da superfície terrestre (EST) é uma propriedade importante na caracterização de alvos através do Sensoriamento Remoto (SR). A estimativa da EST envolve a aplicação de uma função indeterminada de várias variáveis em dados de radiância contaminados por uma atmosfera de complexa modelagem. Dunas, em geral, são compostas por quartzo, cujo comportamento emissivo é bem caracterizado com sensores que operam entre 8–12μm. Neste trabalho foram avaliados 4 métodos de recuperação de temperatura-emissividade a partir de dados de radiância corrigida dos efeitos atmosféricos. Os quatro métodos foram aplicados em dados do subsistema do infravermelho termal (TIR) do sensor ASTER e são: Método da Emissividade Normalizada (MEN), Método da Banda de Referência (MBR), Separação de Emissividade e Temperatura (TES) e Resíduos Alpha (α-Residual). Foram geradas imagens de emissividade, cujas amostras puras (controle) de quartzo foram comparadas com uma curva homóloga da biblioteca espectral do Laboratório de Sensoriamento Remoto do Centro Estadual de Pesquisas em Sensoriamento Remoto e Meteorologia da Universidade Federal do Rio Grande do Sul (UFRGS). Neste trabalho, os métodos foram comparados pelas diferenças na emissividade média, temperatura média de uma imagem ASTER e geometria da curva através de seus valores alphas. Obteve-se como resultado que o método TES apresentou uma emissividade média absoluta maior em relação ao MEN e MBR. A temperatura média para métodos MEN e MBR foi de 35,18ºC, TES de 30,10ºC e o α-Residual não gerou um valor de temperatura, pois não considera esta variável na estimativa do espectro alpha. A geometria da curva do método TES foi a mais próxima da curva espectral de referência. Os métodos comparados neste trabalho não obtiveram um desempenho quantitativo dentro dos limiares certos, é dizer no intervalo de emissividade de um quartzo a 29ºC. Os métodos neste trabalho tiveram uma tendência a superestimar os valores de temperatura e consequentemente os valores de emissividade, devido a uma correção atmosférica inexata em condições de alta umidade, suposições iniciais (emissividade) com grande erro, heterogeneidade do alvo. Em contrapartida se obteve bom desempenho na individualização dos campos de dunas preservando a forma da curva espectral (geometria) do quartzo. / The land surface emissivity (LSE) is an important property in the characterization of targets through Remote Sensing (RS). The estimation of LSE involves the application of an indeterminate function of several variables in radiance data contaminated by an atmosphere of complex modeling. In general, sand dunes are composed of quartz, whose spectral behavior is well characterized with sensors operating between 8-12μm. In this work, four methods of temperature-emissivity recovery were evaluated from atmospheric effects corrected radiance data. The four methods were applied to data from the thermal infrared (TIR) subsystem of the ASTER sensor, and they are: Normalization Emissivity Method (NEM), Reference Channel Method (RCM), Temperature Emissivity Separation (TES) and Alpha Residuals Method (α- Residual). Emissivity images were generated, whose pure quartz samples (control) were compared to a homologous curve of the spectral library of the Remote Sensing Laboratory of the State Center for Remote Sensing and Meteorology Research at the Federal University of Rio Grande do Sul (UFRGS). In this study, the methods were compared by differences in mean emissivity, mean temperature of ASTER image and curve geometry through their alpha values. As a result, the TES method presented a higher mean absolute emissivity, in relation to NEM and RCM. The mean temperature for NEM and RCM methods was 35.18 °C, TES was 30.10 °C and α-Residuals did not generate a temperature value, since it does not consider this variable in the estimation of the alpha spectrum. The geometry of the TES method curve was the closest to the reference spectral curve. The methods compared in this work did not obtain a quantitative performance within the certain thresholds, in the emissivity range of a quartz at 29 °C. The methods tend to overestimate the temperature values and consequently the emissivity values due to an inaccurate atmospheric correction under conditions of high humidity, initial assumptions (emissivity) with great error, heterogeneity of the target. In contrast, a good performance was obtained in the individualization of the dune fields, preserving the shape of the spectral curve (geometry) of the quartz.
70

Faculty Senate Minutes October 6, 2014

University of Arizona Faculty Senate 24 November 2014 (has links)
This item contains the agenda, minutes, and attachments for the Faculty Senate meeting on this date. There may be additional materials from the meeting available at the Faculty Center.

Page generated in 0.0624 seconds