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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.
291

Ferrugem e mancha angular do feijoeiro: efeito de fungicidas no desenvolvimento do hospedeiro e no progresso das doenças. / Bean rust and angular leaf spot of bean: effect of foliar fungicides on the host vegetative development of host and on the progress of the diseases.

Nilceli Fernandes Buzzerio 18 January 2002 (has links)
Foram conduzidos quatro experimentos com a cultivar 'Carioca' do feijoeiro (Phaseolus vulgaris), objetivando a possibilidade de implementação de um sistema de manejo integrado da ferrugem e mancha angular do feijoeiro após a intervenção com os fungicidas oxycarboxin (Hokko Plantvax 750 - 700 gramas/ha) e trifenil hidróxido de estanho (Mertin â - 660 ml/ha), respectivamente, aplicados em diferentes épocas. Foi realizada a quantificação de danos nesses patossistemas, verificando por meio de regressões lineares e não lineares as possíveis relações existentes entre as variáveis integrais AUDPC (área sob a curva de progresso de doença)¸ HAD (duração da área foliar sadia) e HAA (absorção da área foliar sadia) e suas correspondentes HLAI (índice de área foliar sadio) e HRI (absorção da área foliar por unidade de tempo) com a produção (gramas/planta). Os melhores resultados foram obtidos com as variáveis HAD e HAA, com coeficientes de determinação (R 2 ) variáveis entre 0,19 e 0,56 para HAD e 0,23 e 0,49 para HAA. Quando as variáveis HLAI e HRI foram relacionadas com a produção, os coeficientes de determinação variaram entre 0,24 e 0,57 para HLAI e 0,28 e 0,56 para HRI. A partir das avaliações semanais de HLAI e HRI foram realizadas regressões lineares entre estas variáveis e a produção (gramas/planta). Os coeficientes angulares foram relacionados com os estádios de desenvolvimento observando-se a estabilização das curvas entre os estádios R5-R8 para o patossistema ferrugem - feijão e entre os estádios V4-R8 para o patossistema mancha angular - feijão para HLAI e HRI. Nesses experimentos foram também realizadas avaliações do Índice de Área Foliar (LAI) utilizando-se medições diretas (avaliações manuais) e indiretas com ceptômetro. As medições obtidas com o este equipamento apresentaram sensibilidade suficiente para captar as variações no índice de área foliar sadio e portanto podem ser usadas em sistemas de manejo integrado da ferrugem e da mancha angular do feijoeiro. / Four trials were carried out on dry beans (Phaseolus vulgaris), variety 'Carioca' with goal to verify the possibility of implementation of an integrated management system for rust and angular spot after the application with of oxycarboxin (Hokko Plantvax 750 - 700 g/ha) and trifenil stannic hydroxide (Mertin â - 660 ml/ha) fungicides, applied in different timings. The damage quantification in these pathosystems were done analyzing the possible existing relation among the integral variables AUPDC (Area Under Disease Progress Curve), HAD (Healthy Area Duration) and HAA (Healthy Area Absorption) and its correspondents HLAI (Healthy Leaf Area Index) and HRI (Healthy Radiation Intercept) with yield (grams/plant) through linear and non linear regression. The best results were obtained using the variables HAD and HAA with the determination coefficients (R 2 ) from 0.19 to 0.56 for HAD and 0.23 to 0.49 for HAA. When HLAI and HRI were related with yield, the determination coefficient ranged from 0.24 and 0.57 for HLAI and 0.28 to 0.56 for HRI. From weekly assessments of HLAI and HRI, linear regression analysis were done between those variables and yield (grams/plant). The angular coefficient were related with the different crop stages and the stability of curves was observed between R5-R8 stages for rust - dry bean pathosystem and between V4-V8 stages for angular spot – dry bean pathosystem when HLAI and HRI were analyzed. In these experiments, Leaf Area Indice (LAI) was also assessed with direct (manual) and indirect measures with a ceptometer. The measures obtained using this set provided necessary sensibility to catch HLAI variation and, therefore, may be used in an integrated management system of rust and angular spot in dry beans.
292

Tavelures du pommier et de l'olivier : réalisation de modèles épidémiologiques par des méthodes exploitant des observations biologiques acquises au verger / Ascospore release dynamic of Venturia inaequalis (and other ascomycetes) : incidence of temperature (and other factors)

Roubal, Christophe 09 October 2017 (has links)
La modélisation de la dynamique épidémiologique des ascomycètes parasites des arbres fruitiers présente deux aspects très importants : l’évaluation de la quantité d'inoculum et de son évolution, et l’identification des évènements climatiques donnant lieu à une contamination. Le travail présenté aborde ces deux aspects au travers de deux exemples : la tavelure du pommier, et la maladie de l’œil de paon de l’olivier, parasites majeurs pour les filières concernées.L’acquisition des connaissances sur la biologie des deux maladies a été abordée uniquement sur la base de données acquises sur le terrain, ce qui est original car généralement les modèles ont été réalisés sur la base de connaissances établies en conditions contrôlées.Dans le cas de Venturia inaequalis, agent de la tavelure du pommier, la vitesse de développement journalier de l’inoculum a été établie par optimisation numérique, sur la base d’observations réalisées en Provence. Un modèle de dynamique de projection des ascospores incluant la suspension de l’évolution de l’inoculum primaire lors des périodes sèches a été réalisé puis validé sur un jeu de données indépendantes. La transposabilité du modèle a été ensuite étudiée pour une autre région (Aquitaine). Dans le cas de Fusicladium oleagineum, agent de la maladie de l’oeil de paon, les conditions de contamination ont été établies en fonction de la température et de l’hygrométrie, d’une part par la réalisation d’un abaque sur la base de points sélectionnés par dires d’expert, et d’autre part de façon automatique à l’aide d’un système par apprentissage (réseau de neurones). Un modèle, liant la température moyenne après la contamination à l’apparition des symptômes a été ensuite réalisé. / Apple scab, caused by Venturia inaequalis, and peacoq leaf spot, cause by Fusicladiumoleagineum, are key diseases respectively for apple and olive growers. These disease usuallyrequire a large number of treatments. Adequate protection need a good evaluation ofquantitative disponibility of inoculum, and estimation of infection conditions.In this thesis, these two problems were studied using only field data. This is an originalaprroach to obtain knowledge about biology of fungi : most previous works were realised byregression of laboratory data obtained under controled conditions.In the case of Venturia inaequalis, primary inoculum consists of pseudothecia present in leaflitter. Treatments agains ascospore release period is the cornerstone of the strategy againstapple scab. However, the existing forecasting models are not reliable, and are all based ondegree-day time scale, proposed in 1982.Here, using a corpus of data acquired between 1996 and 2013, including observations ofascospore release and weather data, we assessed the daily rate of development of primaryinoculum by fitting generic new time scale functions. Further improvements were then studiedto take into account elements reported in litterature about the incidence of rain or wetness.Different methods were tested and adapted for the parameterisation of models by numericaloptimisation. Some forcasting models were proposed and adapted to the area where the studywas conducted, with parameters including rain and temperature. The validity was tested, andfurther developements of the forecasting tool was then proposed.In the case of Fusicladium oleagineum, a field-operational model predicting disease outbreakswas established as a function of temperature and relative humidity. First with the help ofpoints selected by experts, Secondly automaticaly using a neural network. A model defininglatent period as a function of average temperature after contamination was then realised.
293

Association Rules in Parameter Tuning : for Experimental Designs

Hållén, Henrik January 2014 (has links)
The objective of this thesis was to investigate the possibility ofusing association rule algorithms to automatically generaterules for the output of a Parameter Tuning framework. Therules would be the basis for a recommendation to the user regardingwhich parameter space to reduce during experimentation.The parameter tuning output was generated by means ofan open source project (INPUT) example program. InPUT is atool used to describe computer experiment configurations in aframework independent input/output format. InPUT has adaptersfor the evolutionary algorithm framework Watchmakerand the tuning framework SPOT. The output was imported in Rand preprocessed to a format suitable for association rule algorithms.Experiments were conducted on data for which theparameter spaces were discretized in 2, 5, 10 steps. The minimumsupport threshold was set to 1% and 3% to investigatethe amount of rules over time. The Apriori and Eclat algorithmsproduced exactly the same amount of rules, and the top 5rules with regards to support were basically the same for bothalgorithms. It was not possible at the time to automatically distinguishinguseful rules. In combination with the many manualdecisions during the process of converting the tuning output toassociation rules, the conclusion was reached to not recommendassociation rules for enhancing the Parameter Tuningprocess.
294

Dynamic Spillover Effects in Futures Markets: UK and US Evidence

Antonakakis, Nikolaos, Kizys, Renatas, Floros, Christos 12 March 2016 (has links) (PDF)
Previous studies on spillover effects in future markets have so far confined themselves to static analyses. In this study, we use a newly introduced spillover index to examine dynamic spillovers between spot and futures market volatility, volume of futures trading and open interest in the UK and the US. Based on a dataset over the period February 25, 2008 to March 14, 2013, that encompasses both the global financial crisis and the Eurozone debt crisis, we find that spot and futures volatilities in the UK (US) are net receivers (net transmitters) of shocks to volume of futures trading and open interest. The analysis also sheds light on the dynamic interdependence of spot and futures market volatilities between the US and the UK. Specifically, the spot and futures volatility spillovers between the UK and US markets are of bidirectional nature, however, they are affected by major economic events such as the global financial and Eurozone debt crisis. Several robustness checks endorse our main findings. Overall, these results have important implications for various market participants and financial sector regulators.
295

A top-down approach for creating and implementing data mining solutions

Laurinen, P. (Perttu) 13 June 2006 (has links)
Abstract The information age is characterized by ever-growing amounts of data surrounding us. By reproducing this data into usable knowledge we can start moving toward the knowledge age. Data mining is the science of transforming measurable information into usable knowledge. During the data mining process, the measurements pass through a chain of sophisticated transformations in order to acquire knowledge. Furthermore, in some applications the results are implemented as software solutions so that they can be continuously utilized. It is evident that the quality and amount of the knowledge formed is highly dependent on the transformations and the process applied. This thesis presents an application independent concept that can be used for managing the data mining process and implementing the acquired results as software applications. The developed concept is divided into two parts – solution formation and solution implementation. The first part presents a systematic way for finding a data mining solution from a set of measurement data. The developed approach allows for easier application of a variety of algorithms to the data, manages the work chain, and differentiates between the data mining tasks. The method is based on storage of the data between the main stages of the data mining process, where the different stages of the process are defined on the basis of the type of algorithms applied to the data. The efficiency of the process is demonstrated with a case study presenting new solutions for resistance spot welding quality control. The second part of the concept presents a component-based data mining application framework, called Smart Archive, designed for implementing the solution. The framework provides functionality that is common to most data mining applications and is especially suitable for implementing applications that process continuously acquired measurements. The work also proposes an efficient algorithm for utilizing cumulative measurement data in the history component of the framework. Using the framework, it is possible to build high-quality data mining applications with shorter development times by configuring the framework to process application-specific data. The efficiency of the framework is illustrated using a case study presenting the results and implementation principles of an application developed for predicting steel slab temperatures in a hot strip mill. In conclusion, this thesis presents a concept that proposes solutions for two fundamental issues of data mining, the creation of a working data mining solution from a set of measurement data and the implementation of it as a stand-alone application.
296

Caracterisation de la rupture interfaciale de points soudes d’aciers a tres haute resistance / Characterization of interfacial failures of advanced high strength steels spot welds

Lacroix, Rémi 22 March 2011 (has links)
La détermination de la tenue mécanique de points soudés est un enjeu industriel important, eten particulier dans le cas d’aciers à Très Haute Résistance. Actuellement, l’essai de tractionen croix est l’essai mécanique le plus répandu caractérisant la tenue des points soudés.Toutefois, l’étude de l’influence des différentes zones constituant le point soudé sur la tenueest difficile en se basant sur cet essai.Un essai d’enfoncement de coin a été développé afin de caractériser les ruptures interfacialesdes points soudés. Une section transverse d’un point soudé est observée tandis qu’un coin estinséré entre les deux tôles soudés. Une caméra CCD enregistre l'observation de lapropagation de la fissure.Le pliage limité des tôles durant la fissuration rend efficace la classification des différentspoints soudés par l'énergie totale dissipée par unité de surface rompue. De plus, la mesure insitu de l’angle d’ouverture de fissure caractérise la fissuration stable de la zone fondue. Dessimulations par éléments finis de l’essai sont conduites afin d’estimer un lien entre cesmesures et la rupture du matériau, modélisée par des zones cohésives.La rupture interfaciale de points soudés d’aciers DP et TRIP a été étudiée. Les mesuresexpérimentales permettent d’estimer les paramètres de modèles cohésifs représentatifs de larupture de la zone fondue, constituant des données fiables susceptibles d’être utilisées danstoute simulation numérique du comportement du point soudé. / Characterization of spot weld strength is a key industrial issue, particularly in the case of Advanced High Strength Steels. Today, the most widely used mechanical test evaluating this strength is the Cross Tensile Test. However, investigating the role of the different zones of one spot weld based on this test is difficult.A wedge test has been developed in order to characterize interfacial failures of spot welds. A cross section of one spot weld is observed while a wedge is inserted in between the two welded sheets. A CCD camera records the observation of the propagating crack. The limited sheet bending occurring during crack propagation allows the spot weld classification based on the total energy dissipated per unit fractured area to be efficient.Furthermore, the stable crack propagation is characterized by the in situ measurement of the crack opening angle. Finite element simulations of the test are carried out to estimate a relation between these measurements and the material resistance, approached by a cohesive zone model.Interfacial failures of spot welds of DP and TRIP steels have been investigated. The experimental measurements allow to estimate parameters of a cohesive zone model representative of the molten material failure, providing reliable and appropriate data for simulations of the mechanical behavior of the complete spot weld.
297

The Viability of Installing Mid-Size PV Solar Parks in Sweden : "A paper that evaluates the economic viability of installing mid-size PV solar parks ranging from 250 kW to 2 MW in the village of Åled."

Ghebre, Temesghen Tesfazghi January 2017 (has links)
The ambition of the Swedish government is rapidly concentrating on the development of the renewable energy systems especially on wind energy, bio energy and solar energy. It has been observed on the growth of the production of electricity and heat from these three mentioned renewable energy systems. But, relatively in Sweden the share of production of electricity obtained from PV is quite smaller than the other two. The PV electricity production in Sweden comprises in a large scale of mainly the grid connected distributed PV systems and with a small number of installed solar parks. The aim of this paper is to analyze the viability of installing mid -size PV solar parks in Sweden and to simulate the effect of the proposed project in the village’s (Åled is the village where the proposed site is located) and the country’s electricity production. This study includes designing, simulation and financial analysis of different grid connected centralized mid -size capacities of PV solar parks of 250 kWp,500 kWp,1MWp and 2MWp. They are all fixed ground mounted systems. Moreover, it also discusses the main reasons that hinders decision makers, the PV complications that are connected to the grid, Sweden’s energy regulations particularly the emission regulation and the financial policies of PV. Also, study visit, telephone and email contacts have supplemented it. This study was done with the collaboration of Nyedal Solenergi, in which the proposed site was owned by the company and this paper will be a future guide for the investment of the mid-size PV solar park. According to the study a discussion has been made with the grid supplier (EON) in that area on the investment on one of the designed projects which are presented in this paper. The results of the study show that the effect of the proposed systems on the production of electricity in the village of Åled was between 2.68 – 21.4 % and the impact on the country’s PV electricity production was 0.2 – 1.58 %. And, the possibility of installing mid-size PV solar parks generally in Sweden particularly in the proposed site is possible and economically it is viable but not profitable for system capacities less than 1 MW. As the IRR found for all capacities is greater than the estimated WACC, hence each proposed capacity has the possibility of paying back all its investment costs in about 23 years. So, the profitability is very low in case of the 250 kWp and 500 kWp but for the others they have about 7-8 years of profitability. A sensitivity analysis also has shown the impact of initial investment costs, O & M costs and electricity export rate on the IRR, NPV and equity payback. The initial investment cost and electricity export rate were seen with high effect on the IRR, NPV and equity payback. The LCOE calculated was higher than the average electricity spot price (300 SEK/MWh) for 250 kWp and 500 kWp but lower for the other two capacities. The overall impact for the financial analysis was due to the decreasing of module prices, the rules that changes every year on electricity subsidies for renewables, tax reductions and rapid decreasing of electricity spot prices. In the future if the price of modules continues decreasing, spot price increases, more modification of the subsidy and introduction of new PV technologies integrated with other sources of energy is done then such projects could be more profitable.
298

Epidemiology of citrus black spot disease in South Africa and its impact on phytosanitary trade restrictions

Truter, Mariëtte 23 October 2010 (has links)
Citrus black spot (CBS), caused by Guignardia citricarpa Kiely, occurs in various citrus producing regions of the world. Due to the potential phytosanitary risk associated with the export of fruit from CBS positive production areas to CBS-free countries, restrictive trade barriers have been introduced. This study aimed to further elucidate some epidemiological aspects of CBS that can be used to address critical questions identified in the pest risk assessment submitted by South Africa to the World Trade Organisation to address phytosanitary trade restrictions. Results indicated that Eureka lemon leaf litter exposed to viable pycnidiospores under controlled conditions or in the field in different production regions of South Africa, were not infected and colonised by G. citricarpa. Symptomatic CBS fruit or peel lying on the ground underneath citrus trees therefore can not lead to infection and colonisation of freshly detached leaves or leaf litter, or represent a source of inoculum in citrus orchards. Symptomatic fruit therefore pose no danger for the establishment of the pathogen in CBS-free orchards and are not considered to be a pathway for the pathogen. The period of leaf susceptibility to G. citricarpa was indicated to be maximum eight and ten months from development, for Valencia orange and Eureka lemon, respectively, in a greenhouse study. The susceptibility period of citrus leaves to infection by the black spot pathogen could be longer than previously perceived. Ascospores were captured, using the newly developed Kotzé Inoculum Monitor (KIM), from natural Valencia orange and Eureka lemon leaf litter during October to March with peak ascospore availability between December to February. The KIM is the first sampler designed to capture fungal spores directly from plant material in the laboratory without environmental influences and was effectively used to confirm that ascospores production is seasonal. The KIM in combination with environmental data can be used to improve control through more targeted fungicide applications. Techniques such as isolations and DNA amplification with species-specific primers to detect the pathogen directly from symptomless green leaves have a low success rate due to the restricted growth of the pathogen in latently infected tissue. Artificial leaf wilting enhanced the detection of G. citricarpa from symptomless leaves. Leaf wilting is a reliable, fast and effective method to detect the CBS pathogen and can be applied to monitor citrus nurseries and orchards throughout the year. It can also be applied to monitor pest-free orchards to maintain its CBS pest-free status. This study confirmed that sanitation practices, such as leaf litter removal and mulching of leaf litter with wheat straw can decrease the primary inoculum, ascospores, of CBS and contribute to better management of the disease in a commercial orchard. Regardless of the prevailing climatic conditions each year, control achieved through leaf litter management resulted in >95% clean fruit and are equal to the control achieved with industry standard fungicides. This approach provided improved integrated disease control and an alternative to chemical control. / Thesis (PhD)--University of Pretoria, 2010. / Microbiology and Plant Pathology / unrestricted
299

Comparison of Xanthomonas campestris pv. mangiferaeindicae from mango production areas in South Africa

Gantsho, Nomphelo 20 February 2006 (has links)
Please read the abstract in the dissertation. Copyright / Dissertation (MSc (Plant Pathology))--University of Pretoria, 2007. / Microbiology and Plant Pathology / unrestricted
300

Konvergenz eines plastischen Multiphysics-Kontaktes in der Pressschweißsimulation / Convergence of a Multiphysics-Contact in Simulation of Spot Welding

Kaars, Jonny 07 June 2017 (has links) (PDF)
Es wird ein Überblick über ein Modell zur Simulation des Punktschweißvorganges in Ansys APDL gegeben, Kernproblem sind darin die reibungsbehafteten Kontaktstellen. Die Aspekte der Kontaktmodellierung werden in Zusammenhang mit den Besonderheiten des Modells gebracht. Es wird auf Möglichkeiten der numerischen Kontaktstabilisierung mit Bordmitteln eingegangen. Ferner wird ein Ansatz einer zusätzlichen Kontaktstabilisierung dargestellt und bewertet.

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