• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 4
  • 2
  • 1
  • Tagged with
  • 8
  • 8
  • 4
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
1

Microusinagem de dielétricos com pulsos laser de femtossegundos / Micromachining of dieletrics with femtosecond laser pulses

Machado, Leandro Matiolli 24 August 2012 (has links)
Neste trabalho foi utilizado o método de regressão do diâmetro para a medida do limiar de ablação nos materiais Suprasil, BK7, Safira e Ti:Safira por pulsos de femtossegundos. Através de medidas dos limiares de ablação para pulsos únicos e pulsos sobrepostos, quantificou-se o parâmetro de incubação para cada dielétrico. Essas medidas preliminares serviram para validação do método denominado Diagonal Scan ou D-scan. Para tanto, o método D-scan teve seu formalismo expandido o que possibilitou a quantificação da sobreposição de pulsos durante o seu uso. A simplicidade e rapidez do método D-scan permitiram que o limiar de ablação no BK7 fosse medido para diferentes larguras temporais e sobreposições. O limiar de ablação para pulsos únicos em função da largura temporal dos pulsos foi comparado com uma simulação teórica. A partir do conhecimento do parâmetro de incubação desenvolveu-se uma metodologia de usinagem em dielétricos que considera a sobreposição de pulsos durante a ablação. Isso permitiu a fabricação de microcanais para uso em microfluídica em BK7. / In this study, the diameter regression method was used to measure the ablation threshold of Suprasil, BK7, Sapphire and Ti: Sapphire by femtosecond pulses. Through measurements of the ablation thresholds for single and overlapping pulses, the incubation parameter for each dielectric was quantified. These preliminary steps were used to validate the method called Diagonal Scan or D-scan. This was made possible by expanding the D-scan formalism, which allowed the quantification of overlapping pulses during its use. The simplicity of the D-scan method allowed the ablation threshold measurement in BK7 for different temporal widths and overlaps. The ablation threshold for single pulse for different temporal width was compared with a theoretical simulation. From the knowledge of the parameter of incubation, a methodology that considers dielectric machining overlapping pulses during ablation was developed. This allowed the manufacture of microchannels on BK7 for microfluidics.
2

Modelling and Testing Strategies for Brittle Fracture Simulation in Crystalline Rock Samples

Ghazvinian, Ehsan 24 September 2010 (has links)
The failure of brittle rocks around deep underground excavations due to the high induced stress is controlled by the crack accumulation in the rock. The study shows that the damage initiation strength, CI, corresponds to the long-term strength, and the short-term strength of the brittle rocks in-situ is the crack interaction strength, CD. Therefore the damage thresholds that are being used for the calibration and validation of numerical models are important parameters in the design of underground structures. The accurate detection of the damage thresholds is important as they define the in-situ behaviour of the brittle rocks. The two most common methods of detecting damage thresholds are the Acoustic Emission method and the strain measurement method. Apparent discrepancy that exists between the accuracy of these methods was the author’s motivation for comparing these two methods on Stanstead and Smaland granites. The author introduced two new parameters based on the measured strains for improving the strain measurement method. Based on the comparisons, the author is of the opinion that the Acoustic Emission method is a more accurate method of detecting damage thresholds. Numerical models are an important tool in the design of underground structures. The numerical methods that are able to simulate fractures explicitly have the ability to predict the brittle failure, the density and the extension of the microcracks around the opening. Itasca’s Particle Flow Code (PFC) was used in this study due to its potential to simulate fractures explicitly. Calibration of PFC models to Unconfined Compressive Strength properties of the rock does not mean that the model will behave correctly under other confining stresses or in tension. The author has tried to solve this problem by different methods and developing new procedures. Improvements in the model behaviour have been achieved but more work is required. The definition, and detection and calibrated simulation of rock damage thresholds for calibration of numerical models is helpful for a successful design of underground excavations and long term, lower bound strength, a critical design parameter for deep geological repositories for the storage of nuclear wastes, for example. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2010-09-23 13:59:28.795
3

Microusinagem de dielétricos com pulsos laser de femtossegundos / Micromachining of dieletrics with femtosecond laser pulses

Leandro Matiolli Machado 24 August 2012 (has links)
Neste trabalho foi utilizado o método de regressão do diâmetro para a medida do limiar de ablação nos materiais Suprasil, BK7, Safira e Ti:Safira por pulsos de femtossegundos. Através de medidas dos limiares de ablação para pulsos únicos e pulsos sobrepostos, quantificou-se o parâmetro de incubação para cada dielétrico. Essas medidas preliminares serviram para validação do método denominado Diagonal Scan ou D-scan. Para tanto, o método D-scan teve seu formalismo expandido o que possibilitou a quantificação da sobreposição de pulsos durante o seu uso. A simplicidade e rapidez do método D-scan permitiram que o limiar de ablação no BK7 fosse medido para diferentes larguras temporais e sobreposições. O limiar de ablação para pulsos únicos em função da largura temporal dos pulsos foi comparado com uma simulação teórica. A partir do conhecimento do parâmetro de incubação desenvolveu-se uma metodologia de usinagem em dielétricos que considera a sobreposição de pulsos durante a ablação. Isso permitiu a fabricação de microcanais para uso em microfluídica em BK7. / In this study, the diameter regression method was used to measure the ablation threshold of Suprasil, BK7, Sapphire and Ti: Sapphire by femtosecond pulses. Through measurements of the ablation thresholds for single and overlapping pulses, the incubation parameter for each dielectric was quantified. These preliminary steps were used to validate the method called Diagonal Scan or D-scan. This was made possible by expanding the D-scan formalism, which allowed the quantification of overlapping pulses during its use. The simplicity of the D-scan method allowed the ablation threshold measurement in BK7 for different temporal widths and overlaps. The ablation threshold for single pulse for different temporal width was compared with a theoretical simulation. From the knowledge of the parameter of incubation, a methodology that considers dielectric machining overlapping pulses during ablation was developed. This allowed the manufacture of microchannels on BK7 for microfluidics.
4

Measurements of Nonlinear Optical and Damage Properties of Selected Contemporary Semiconductor Materials

Carpenter, Amelia 07 August 2023 (has links)
No description available.
5

Quantifying Asiatic garden beetle (<i>Maladera castanea</i>) populations and their impacts on commercial mint production

Connor Eric Sturr (17583585), Doug richmond (17583727), Elizabeth Y. Long (17583733), Christian Krupke (17583735) 07 December 2023 (has links)
<p dir="ltr">The Asiatic garden beetle (AGB), in its larval stage, has become an increasingly detrimental to the health of commercially grown mint in northern Indiana by feeding on their roots. In my research, I have optimized a method to quantify populations by determining the proper sample size to maintain accurate and precise estimates, determining the best sampling method and sampling scheme. Additionally, I established the relationship between AGB larval feeding and mint performance and have established a threshold of the average number of larvae required to cause significant yield loss. </p>
6

Danos causados por doencas fungicas foliares em aveia branca / Damage caused by fungal leaf disease in white

Nerbass Junior, João Martinho 06 March 2008 (has links)
Made available in DSpace on 2016-12-08T16:44:38Z (GMT). No. of bitstreams: 1 PGPV08MA069.pdf: 749700 bytes, checksum: 8827df9f189a59df731fb6cc3e561047 (MD5) Previous issue date: 2008-03-06 / The white oat (Avena sativa L.) is a winter cereal adapted different regions, used in the production of grains, green grass, hay, silage and mutch soil coverage in the winter. The leaf rust and helminthosporium are considered frequent diseases in oats. The damages are due to the reduction of the plant green area photosynthesis. This report aimed to obtain equations of damage function to multiple pathosystem involving leaf rust and helminthosporiosis in two white oat cultivars and correlate the disease intensity with the yield components. The experiments were performed in the Center of Agroveterinarian Sciences, Santa Catarina State University, Lages, SC experimental area, in the 2006 and 2007 agricultural harvest. The leaf diseases degree was generated through the use of increasing doses and number of applications (one, two and four) of pyraclostrobina + epoxiconazole (33.25 +12.5, 49.87 +18.75, 66.5 +25 g ai ha-1) fungicide in UPFA 20 Teixeirinha and UPFA 22 Temprana cultivars. The experimental units consisted of five lines of sowing, spaced at 0.20 m and five meters in length. Were analyzed the following variables: leaf incidence and severity, grain yield, a thousand grain mass and hectoliter weight. The disease evaluations were performed every 10 days pulling up randomly 10 plants per plot. Generally the helminthosporiosis was the prevalent disease in both agricultural harvest and oat cultivars until the flowering beginning. The leaf rust had its intensity increased in subsequent stages. In the first part of this study was attempted to determine the equations of damage function by the regression analysis between disease intensity and grain yield for each plant development stage. Significant equations were obtained for the UPFA 20 and UPFA 22 cultivars in both agricultural harvests, where through them was possible to calculate the Economic Damage Threshold (EDT) by phonological stage of culture. In its second part, the leaf incidence and severity values were submitted to the Area Under the Disease Progress Curve (AUDPC), which were correlated with the grain yield, thousand grain mass and hectoliter weight. There were negative and significant correlations from the AUDPC with grain yield, thousand grain mass and hectoliter weight in both growing season. From these values it was achieved that as higher is the leaf diseases intensity highest are the AUDPC values, resulting in the decrease of productive variables values. With values of grain yield, thousand grain mass and hectoliter weight the third work purpose quantify the economic damage treschold and control percentage of these two diseases according to the number and dose of fungicide application. The damage to the grain yield, thousand grains mass and hectoliter weight were higher in the 2007 harvest for both cultivars. The leaf diseases control percentage was higher in both cultivars in the 2007 harvest, reaching based on the leaf severity 86.74 % and 85.90 % respectively for UPFA 20 and UPFA 22 / A aveia branca (Avena sativa L.) é um cereal de estação fria adaptado a diferentes regiões, usada na produção de grãos, forragem verde, feno, silagem, e cobertura verde/morta de solo no inverno. A ferrugem da folha e a helmintosporiose são consideradas doenças freqüentes em aveia. Os danos causados são atribuídos à redução da área foliar fotossintetizante ativa da planta. O objetivo deste trabalho foi obter equações da função de dano para patossistema múltiplo envolvendo ferrugem da folha e helmintosporiose em duas cultivares de aveia branca e correlacionar a intensidade das doenças com componentes do rendimento. Os experimentos foram conduzidos na área experimental do Centro de Ciências Agroveterinárias, Lages, SC, nas safras agrícolas de 2006 e 2007. O gradiente das doenças foliares foi gerado pelo uso de doses crescentes e número de aplicações (uma, duas e quatro) do fungicida piraclostrobina + epoxiconazole (33,25+12,5, 49,87+18,75, 66,5+25 g de i.a. ha- 1) nas cultivares UPFA 20 Teixeirinha e UPFA 22 Temprana. As unidades experimentais constaram de cinco linhas de semeadura, espaçadas em 0,20 m, com cinco metros de comprimento. Analisaram-se as seguintes variáveis: incidência e severidade foliar, rendimento de grãos, massa de mil grãos e peso do hectolitro. As avaliações de doença foram realizadas a cada 10 dias retirando-se 10 plantas aleatoriamente das parcelas. Em geral a helmintosporiose foi a doença predominante nas duas safras agrícolas e duas cultivares de aveia até o início do florescimento. A ferrugem da folha teve sua intensidade aumentada nos estádios subseqüentes. Na primeira parte deste trabalho procurou-se determinar as equações da função de dano pela análise de regressão entre intensidade de doença e rendimento de grãos para cada estádio de desenvolvimento das plantas. Foram obtidas equações significativas para as cultivares UPFA 20 e UPFA 22 nas duas safras agrícolas, onde por meio destas pode-se calcular o Limiar de Dano Econômico por estádio fenológico da cultura. Em sua segunda parte, os valores de incidência e severidade foliar foram utilizados para calcular à Área Abaixo da Curva de Progresso da Doença (AACPD), os quais foram correlacionados com o rendimento de grãos, massa de mil grãos e peso do hectolitro. Houve correlações negativas e significativas da AACPD com rendimento de grãos, massa de mil grãos e peso do hectolitro nas duas safras agrícolas. Destes concluiu-se que quanto maior a intensidade das doenças foliares maior são os valores da AACPD, resultando na diminuição dos valores das variáveis produtivas. De posse dos valores de rendimento de grãos, massa de mil grãos e peso do hectolitro a terceira parte deste trabalho teve como objetivo quantificar o percentual de dano, e controle destas duas doenças em função do número e dose de aplicação do fungicida. Os danos ao rendimento de grãos, massa de mil grãos e peso do hectolitro foram maiores na safra de 2007 para as duas cultivares. A percentagem de controle das doenças foliares foi maior nas duas cultivares na safra de 2007, atingindo com base na severidade foliar 86,74 % e 85,90 %, respectivamente para UPFA 20 e UPFA 22
7

Danos e controle químico da mancha marrom e do oídio da cevada / Damage and chemical control of brown spot and powdery mildew of barley

Agostinetto, Lenita 08 February 2011 (has links)
Made available in DSpace on 2016-12-08T16:44:42Z (GMT). No. of bitstreams: 1 PGPV11MA101.pdf: 1302742 bytes, checksum: b7efc06d336ca4a49c0225d1d0b03cfb (MD5) Previous issue date: 2011-02-08 / The objectives of the work were: a) to obtain the damage function equations for multiple pathosystem to calculate the EDT to time fungicides application; b) to quantify the control and damage of the yield components, and c) To relate the brown spot incidence and severity in different growth stages. The experiments were carry out at the NBN Seeds Company during the 2009 and 2010 crop seasons, located in Muitos Capões county, Rio Grande do Sul state, Brazil and in the Agro science Center at Santa Catarina State University only in 2010. The cultivar BRS Cauê was used as susceptible cultivar to brown spot and powdery mildew. The experiments design was in randomized block with four replications. The nine treatments consisting of different rates (half and recommended rates) and fungicide applications number (one, two, three and four) of mixture strobilurin and triazole fungicides, generating the disease gradients intensity. The total area of 5.0 x 2.5 m was the experimental unit in both experiments. The fungicide applications and incidence and severity assessment were done at EC 22, EC 31, EC 39, EC 45 and EC 56 plant development stages. Plants from central rows of each plot were manually harvested and grain yield (GY), one-thousand grain weight (TGW) and granulometry (G) were evaluated. In the first chapter, the damage function equations between disease intensity and GY for each plant development stages, obtained by regression analysis, in both 2009-10 crop growing seasons were significant and negative indicative that increasing disease severity lead into decreasing grain yield. The damage coefficients of these equations can be used to calculate the economic damage threshold. In the second chapter, the values of disease intensity were used to calculate the area under disease progress curve (AUDPC). The GY, TGW, G and AUDPC values were tested using the mean comparison between treatments and the percentage of damage and disease control were determinated. The largest 2009 crop damage was 45.87%, 15.47% and 25.84% for GY, G and TGW, respectively. The ultimate control was 68.11% when considered the severity and four foliar applications, independent of the used dose. In 2010, the greatest damage were 31.16%, 14.02% and 10.76% in Muitos Capões and 39.44%, 23.59% and 45.88%, in Lages, for GY, 10 TGW and G, respectively. The highest percentage of control, based on the leaf severity were 71.63% and 73.96% for Muitos Capões and Lages, respectively. The greater control, independent of used dose were obtained with three and four applications in Muitos Capões and four applications in Lages. In the third chapter, brown spot incidence and severity data were subjected to regression analysis and correlation and the obtained values were significant and positive. The brown spot and powdery mildew diseases incidence and severity recommended by the Technique Indication of crop (TIC) to initiate fungicide applications is 20% and 5% respectively. The severity average values for initiating chemical control are 0.77% and 0.34% respectively for 2009 and 2010 crop seasons when the incidence diseases were substituted in the equations. These values are lower than TIC recommended values / Os objetivos do trabalho foram: a) obter equações de função de dano para patossistema múltiplo para calcular o LDE servindo como critério indicador de aplicação de fungicidas; b) quantificar controle e dano nos componentes de rendimento; e c) relacionar incidência e severidade foliar da mancha marrom em diferentes estádios fenológicos. Os experimentos foram conduzidos nas safras agrícolas 2009 e 2010 na NBN Sementes no município de Muitos Capões, RS; e, na safra de 2010 no Centro de Ciências Agroveterinárias no município de Lages, SC. Em todos os experimentos foi utilizada a cultivar BRS Cauê suscetível à mancha marrom e oídio. O delineamento foi blocos casualisados, com quatro repetições e nove tratamentos constituídos de diferentes doses (meia dose e dose indicada) e número (uma, duas, três e quatro) de aplicações de fungicidas triazóis e estrobilurinas para gerar os gradientes de intensidade das doenças. A área de cada unidade experimental correspondeu a 5,0 x 2,5 m. As aplicações e as avaliações da incidência e severidade foliar ocorreram nos estádios de crescimento (EC) EC 22, EC 31, EC 39, EC 45 e EC 56. A colheita foi manual cortando as plantas das linhas centrais de cada parcela. Foram avaliados rendimento de grãos (RG), massa de mil grãos (MMG) e granulometria (G). No primeiro capítulo, as equações de função de dano entre intensidade de doença e RG para cada EC, obtidas por análise de regressão, em ambas as safras agrícolas, foram significativas e negativas, ou seja, à medida que aumentou a intensidade de doença, diminuiu o RG. Os coeficientes de dano obtidos podem ser utilizados no cálculo do limiar de dano econômico. No segundo capítulo, os valores de intensidade das doenças foram usados para o cálculo da área abaixo da curva de progresso da doença (AACPD). Os valores de RG, MMG, G e AACPD foram submetidos ao teste de comparação de médias. Foram determinados o percentual de dano e de controle das doenças. Na safra 2009, os maiores danos foram 45,87%, 15,47% e 25,84% para RG, MMG e G, respectivamente. O controle máximo foi 68,11% considerando a severidade foliar e quatro aplicações, independente da dose usada. Em 2010, os maiores danos foram 31,16%, 14,02% e 10,76% em Muitos Capões e 39,44%, 23,59% e 8 45,88% em Lages, respectivamente para R, MMG e G. Com base na severidade obteve-se controle de 71,63% e 73,96% em Muitos Capões e Lages, respectivamente. Em Muitos Capões três e quatro aplicações e em Lages quatro aplicações, independente da dose, apresentaram maior percentual de controle. No terceiro capítulo, os dados de incidência e severidade foliar de mancha marrom foram submetidos à análise de regressão e correlação. As equações obtidas foram significativas e positivas. A incidência e a severidade foliar recomendado pela Indicação Técnica da cultura (ITC) para iniciar as aplicações de fungicidas é de 20% e 5%, respectivamente. Substituindo esse valor de incidência nas equações obtidas têm-se valores médios de severidade para iniciar o controle químico de 0,77% e 0,34% respectivamente para 2009 e 2010, inferior ao recomendado pela ITC
8

Untersuchungen zur Schadwirkung von Sclerotinia sclerotiorum (Lib. de Bary) und Verticillium longisporum (comb. nov. Karapapa) in Winterraps (Brassica napus) / Investigations on the damage potential of Sclerotinia sclerotiorum (Lib. de Bary) and Verticillium longisporum (comb. nov. Karapapa) in winter oilseed rape (Brassica napus)

Dunker, Sarah 02 February 2006 (has links)
No description available.

Page generated in 0.0518 seconds