abstract: Early-age cracks in fresh concrete occur mainly due to high rate of surface evaporation and restraint offered by the contracting solid phase. Available test methods that simulate severe drying conditions, however, were not originally designed to focus on evaporation and transport characteristics of the liquid-gas phases in a hydrating cementitious microstructure. Therefore, these tests lack accurate measurement of the drying rate and data interpretation based on the principles of transport properties is limited. A vacuum-based test method capable of simulating early-age cracks in 2-D cement paste is developed which continuously monitors the weight loss and changes to the surface characteristics. 2-D crack evolution is documented using time-lapse photography. Effects of sample size, w/c ratio, initial curing and fiber content are studied. In the subsequent analysis, the cement paste phase is considered as a porous medium and moisture transport is described based on surface mass transfer and internal moisture transport characteristics. Results indicate that drying occurs in two stages: constant drying rate period (stage I), followed by a falling drying rate period (stage II). Vapor diffusion in stage I and unsaturated flow within porous medium in stage II determine the overall rate of evaporation. The mass loss results are analyzed using diffusion-based models. Results show that moisture diffusivity in stage I is higher than its value in stage II by more than one order of magnitude. The drying model is used in conjunction with a shrinkage model to predict the development of capillary pressures. Similar approach is implemented in drying restrained ring specimens to predict 1-D crack width development. An analytical approach relates diffusion, shrinkage, creep, tensile and fracture properties to interpret the experimental data. Evaporation potential is introduced based on the boundary layer concept, mass transfer, and a driving force consisting of the concentration gradient. Effect of wind velocity is reflected on Reynolds number which affects the boundary layer on sample surface. This parameter along with Schmidt and Sherwood numbers are used for prediction of mass transfer coefficient. Concentration gradient is shown to be a strong function of temperature and relative humidity and used to predict the evaporation potential. Results of modeling efforts are compared with a variety of test results reported in the literature. Diffusivity data and results of 1-D and 2-D image analyses indicate significant effects of fibers on controlling early-age cracks. Presented models are capable of predicting evaporation rates and moisture flow through hydrating cement-based materials during early-age drying and shrinkage conditions. / Dissertation/Thesis / Ph.D. Civil and Environmental Engineering 2011

Four studies were performed to evaluate the independent influence of core temperature and heat acclimation on sweating responses when exercise is fixed for a given evaporative heat balance requirement (Ereq) during compensable and uncompensable heat stress. By using circadian rhythm to modulate absolute core temperature, study 1 investigated whether absolute core temperature altered the steady-state sweat rate during compensable heat stress at a fixed Ereq. Study 2 compared the influence of partial and complete heat acclimation on core temperature and sweating responses between a compensable and uncompensable heat stress condition. Study 3 quantified how maximum skin wettedness is altered with partial or complete heat acclimation. Study 4 determined whether aerobic fitness (i.e. maximum rate of oxygen consumption; VO2max) per se independently alters the sweating and core temperature responses to uncompensable heat stress or if the frequent bouts of exercise-induced heat stress that accompany aerobic training are required to augment thermoregulatory capacity. Study 1 demonstrated that when absolute core temperature is different between AM and PM by ~0.2°C, steady-state sweat rates were the same for a fixed Ereq. Only when a different level of Ereq was attained, were differences in steady-state sweating observed. Moreover, steady-state sweat rates were similar despite differences in skin and core temperature when exercise intensity was matched to elicit a fixed Ereq in two different ambient temperatures (23°C and 33°C). In study 2, neither partial nor complete heat acclimation altered the core temperature response to compensable heat stress despite a marginally greater sweat rate compared to an unacclimated state. However, the sudomotor adaptations associated with heat acclimation were evident during uncompensable heat stress and mitigated the rise in core temperature during 60 minutes of exercise compared to an unacclimated state. Study 3 determined that the biophysical parameter that defines the upper limit for evaporative heat loss, that is the maximum skin wettedness achievable, increased following partial (0.84±0.08) and complete heat acclimation (0.95±0.05) compared to unacclimated (0.72±0.06) which directly explains the reduced change in core temperature reported in study 2 during uncompensable heat stress. Lastly, study 4 demonstrated that VO2max per se does not alter the sudomotor responses to uncompensable heat stress. Rather, it is the repetitive exercise-induced heat stress experienced during aerobic training that induces a partial heat acclimation thereby mitigating the rise in core temperature during uncompensable heat stress. Taken together, when exercise is prescribed in a compensable environment, the steady-state sweat rate observed will be primarily determined by Ereq independent of absolute core temperature, while heat acclimation will slightly increase the sweat rate despite providing no additional reduction in the change in core temperature. However, progressive heat acclimation increases the upper limit of compensability via a greater maximum skin wettedness thereby mitigating the rise in core temperature during uncompensable heat stress.

Terrestrial evapotranspiration (ET) is a significant component of the energy and water balances at the land surface. However, direct, continuous measurements of ET are spatially limited and only available since the 1990s. Due to this lack of observations, detecting and attributing long-term regional trends in ET remains difficult. This dissertation aims to alleviate the data limitation and detect long-term trends by developing a method to infer ET from data collected at common weather stations, which are spatially and temporally abundant. The methodology used to infer ET from historical meteorological data is based on an emergent relation between the land surface and atmospheric boundary layer. We refer to this methodology as the Evapotranspiration from Relative Humidity at Equilibrium method, or the “ETRHEQ method”. In the first section of this dissertation, we develop the ETRHEQ method for use at common weather stations and demonstrate the utility of the method at twenty eddy covariance sites spanning a wide range of climate and plant functional types. Next, we apply the ETRHEQ method at historical weather stations across the continental U.S. and show that ET estimates obtained via the ETRHEQ method compare well with watershed scale ET, as well as ET estimates from land surface models. From 1961 to 1997, we find negligible or increasing trends in summertime ET over the central U.S. and the west coast and negative trends in the eastern and western U.S. From 1998 to 2014, we find a sharp decline in summertime ET across the entire U.S. We show that this decline is consistent with decreasing transpiration associated with declines in humidity. Lastly, we assess the sensitivity of ET to perturbations in soil moisture and humidity anticipated with climate change. We demonstrate that the response of ET to changing humidity and soil moisture is strongly dependent on the biological and hydrological state of the surface, particularly the degree of water stress and vegetation fraction. In total, this dissertation demonstrates the utility of the ETRHEQ method as a means to estimate ET from weather station data and highlights the critical role of vegetation in modulating ET variability.

Orientador: Antonio Evaldo Klar / Banca: João Carlos Cury Saad / Banca: Dinival Martins / Banca: Reginaldo Ferreira Santos / Banca: Mariana Fraga S. Muçouçah / Resumo: O manejo da água de irrigação em uma cultura é de fundamental importância pois permite o uso racional deste fator de produção visando a obtenção da máxima produção por unidade de água aplicada. Aliado a essa tecnologia, o cultivo em ambiente protegido possibilita produção contínua em épocas do ano em que as condições a campo normalmente são desfavoráveis, possibilitando o abstecimento do mercado nacional em todas as estações. A fim de conhecer as variáveis meteorológicas que mais afetam a produção nesse ambiente, conduziu-se uma pesquisa na área experimental do Departamento de Engenharia Rural da Universidade Estadual Paulista UNESP, campus de Botucatu, com o objetivo de avaliar o efeito de diferentes potenciais de irrigação na produção de três variedades de alface (lisa, crespa e americana) cultivadas em épocas distintas. Foi também realizada a espacialização do ambiente protegido mediante a distribuição de minievaporímetros para verificação da distribuição de energia em três alturas, 40, 80 e 120 cm do solo. O trabalho foi conduzido em estufa plástica, com orientação Noroeste Sudoeste, o sistema de irrigação adotado foi por gotejamento. Os parâmetros avaliados no trabalho foram o número de folhas, diâmetro de cabeça, massa fresca, massa seca, variáveis climatológicas, bem como a evaporação semanal dos minievaporímetros, durante 6 meses. Os resultados obtidos indicaram que o potencial que apresentou melhor produção e eficiência de uso da água foi 35kPa, com ajuste quadrático, e máxima eficiência técnica próxima dos 34,8 kPa. As épocas que 2 apresentaram melhor produção de massa fresca para as três variedades foram maio-junho, julho-setembro e setembro-novembro. O cultivo realizado em fevereiro-abril, apresentou menor produção de massa fresca para todas as variedades cultivadas. A produção de massa seca não apresentou... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The knowledge of meteorological elements in protected environment is very important for commercial plants, because of possibility to produce for all the year according to the study now conduced in Botucatu SP, in order to evaluate the effects of different irrigation treatments on three lettuce cultivars. (lisa, crespa and american). Simultaneously, energy distribution in the environment also was studied, through minievaporimeters placed at three heights 40, 80 and 120 cm from the soil surface. The study was developed in a polyethilene tunnel with orientation Northeast/Southwest (NE/SW) and the fertigation through drip irrigation. Leaf number, head diameter, fresh weigh, dry weigh, meteorological elements and evaporation from minievaporimeters were determined. Four treatments were applied: 20, 28, 35 and 45 kPa and the results showed the treatment 35 kPa showing the highest lettuce production and maximum water efficiency use. The highest productions occurred in the May/June, July/September and September/November, while the worst one was in the February/April. There was not significant difference of dry mass production among the treatments, independently of the year period with exception of the crespa cultivar which was superior in September/November. The evaporation distribution showed larger values in the 40 cm height at coldest months, while the largest evaporation at 80 4 cm occurred from July 30 to September 16. On the other hand, the minievaporimeters from 120 cm did not show variation along the period studied. The South face showed the highest evaporation. / Doutor

学位授与大学：京都大学 ; 取得学位: 博士(工学) ; 学位授与年月日: 2007-09-25 ; 学位の種類: 新制・課程博士 ; 学位記番号: 工博第2860号 ; 請求記号: 新制/工/1420 ; 整理番号: 25545 / Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第13389号 / 工博第2860号 / 新制||工||1420(附属図書館) / 25545 / UT51-2007-Q790 / 京都大学大学院工学研究科航空宇宙工学専攻 / (主査)教授 青木 一生, 教授 稲室 隆二, 教授 斧 髙一 / 学位規則第4条第1項該当

Ultrathin films of Cobalt, Iron and Manganese have been thennally evaporated onto an fcc Copper (111) single crystal substrate and investigated using a variety of surface structural teclmiques. The small lattice mismatch between these metals and the Cu (111) substrate make them an ideal candidate for the study of the phenomena of pseudomorphic film growth. This is important for the understanding of the close relationship between film structure and magnetic properties. Growing films with the structure of their substrate rather than their bulk phase may provide an opportunity to grow materials with novel physical and magnetic properties, and hence new technological applications. Both Cobalt and Iron have been found to initially maintain a registry with the fee Cu (111) surface in a manner consistent with pseudomorphic growth. This growth is complicated by island rather than layer-by-layer growth in the initials stages of the film. In both cases a change in the structure of the film seems to occur at a point where the coalescence of islands in the film may be expected to occur. When the film does change structure they do not form a perfect over-layer with the structure of their bulk counterpart. The films do contain a number of features representative of the bulk phase but also contain considerable disorder and possibly remnants of fcc (111) structure. The order present in these films can be greatly improved by annealing. Manganese appears to grow with an fee Mn (111) lattice spacing and there is no sign of a change in structure in films of up to 4.61 ML thick. The gradual deposition and annealing of a film to 300°C, with a total deposition time the same as that for a 1 ML thick film, causes a surface reconstruction to occur that is apparent in a R30° (√3×√3) LEED pattern. This is attributed to the formation of a surface alloy, which is also supported by the local expansion of the Cu lattice in the (111) direction.

Made available in DSpace on 2016-08-15T20:30:55Z (GMT). No. of bitstreams: 1 LeonardoLMC_DISSERT.pdf: 1176741 bytes, checksum: cae29c28ee7539a3660b0db230755381 (MD5) Previous issue date: 2010-08-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / We evaluated the Thermoregulation of the scrotum associated with quality semen of goats grazed in the meteorological conditions of the semi-arid. 10 goats were used. There were 5 observations, with four days of interval. Five groups were formed, each group was collected in different hours (8am, 10am, 12pm, 2pm and 4pm). The skin surface body temperatures (SSBT) and the scrotum (ST), respiratory rate and rectal temperature were recorded. Heat loss by cutaneous evaporation was measured from the H2O/CO2 analyzer, in the body was used a vented cap and in the scrotum was developed a ventilated capsule adapted for that region. The area of scrotum was determined through analysis of regression. Semen was collected via an artificial vagina and evaluated macro-and microscopically. Irradiance, wind speed, air, wet bulb and black globe temperatures were recorded. The Statistical analysis was based on the method of least squares. For analysis of quality of the semen it was used a 5x5 Latin square design. The SSBT 34.5 ±0.92ºC and ST was 33.5 ±0.36ºC, showing a difference of 1ºC between those regions. The latent heat loss was 57.3 ±18.0 W.m-2 for body surface and 49.4 ±15.0 Wm-2 to the scrotum. Semen samples were considered of good quality at all times and days of collection. The conclusion was that the difference between the surface temperatures derive from a combination of mechanisms which involve thermoregulation of the scrotum, and the animals can be utilized for breeding at any time of the day. / Avaliou-se a Termorregulação da bolsa escrotal associada à qualidade do sêmen de caprinos manejados nas condições meteorológicas do semiárido. Foram utilizados 10 caprinos. Foram realizadas 5 observações, com 4 dias de intervalo entre elas. Formou-se 5 grupos, onde cada grupo era coletado em horas distintas (8, 10, 12, 14 e 16h). As temperaturas da superfície cutânea do corpo (TSPSC) e da bolsa escrotal (TSPBE) e retal e freqüência respiratória foram registradas. A perda de calor por evaporação cutânea foi mensurada a partir do analisador de H2O/CO2, no corpo foi utilizada uma cápsula ventilada e na bolsa escrotal foi desenvolvida uma cápsula ventilada adaptada para esta região. A área da bolsa escrotal foi determinada através de análise de regressão. O sêmen foi colhido através de uma vagina artificial e avaliado macro e microscopicamente. Foram registradas a irradiância, velocidade do vento e temperaturas do ar, do bulbo úmido e do globo negro. A análise estatística foi baseada no método dos quadrados mínimos. Para análise da qualidade do sêmen foi utilizado um delineamento quadrado latino 5x5. A TSPSC 34,5 ±0,92ºC e TSPBE foi 33,5 ±0,36ºC, demonstrando diferença de 1 ºC entre estas regiões. A perda de calor latente foi de 57,3 ±18,0W.m-2 para a superfície do corpo e de 49,4 ±15,0 W.m-2 para a bolsa escrotal. O semên foi considerado de boa qualidade em todos os horários e dias de coleta. Cocluiu-se que a diferença ente as temperaturas de superfícies deriva de uma associação de mecanismos que envolve a termorregulação da bolsa escrotal e que os animais podem ser utlizados para reprodução a qualquer hora do dia.

Este trabalho versou sobre a obtenção de partículas nanoestruturadas de ZnO pela técnica de evaporação térmica a partir de zinco metálico. Basicamente, a síntese ocorria em um reator de quatzo colocado em um forno tipo mufla, onde o zinco metálico reagia com uma atmosfera oxidante, proporcionada pela injeção de ar comprimido. Inicialmente, o forno era aquecido a temperaturas que variaram de 850 a 1050°C. Posteriormente, a amostra de zinco metálico era inserida na zona de aquecimento no interior do tubo, em quantidade de 2,5g, 5g, 10g, 20g e 30g. A injeção de argônio (99,99% de pureza), para o transporte das partículas de ZnO para fora da zona de reação, ocorria com um fluxo de 1 a 5L/min. O tempo de reação foi controlado e as regiões de ocorrência das reações variadas. Após o término das reações, o forno era resfriado à temperatura ambiente para a realização da coleta das amostras. A pressão utilizada durante as reação foi a pressão atmosférica. O material produzido foi analisado para a caracterização da estrutura cristalina (por difração de raios-x), morfologia (por microscopia eletrônica de varredura e transmissão, com auxílio do software Image Tool para a estimativa de tamanho de partícula) e área superficial (método BET). O band gap do ZnO foi determinado por análise de transmitância, refletância e absorbância, utilizando um espectrofotômetro com acessório de refletância difusa, através de medidas de refletividade de infravermelho difuso no pó óxido de zinco. Os dados de absorção foram calculados em função de Kubelka-Munk. A atividade fotocatalítica foi avaliada através do processo de degradação de uma solução de alaranjado de metila em um reator fotoquímico de iluminação UVA, com sua descoloração sendo observada através da espectroscopia UV-Vis. As partículas nanoestruturadas de ZnO produzidas tiveram suas características influenciadas pelos parâmetros de síntese. A morfologia variou desde formas aciculares a tetrápodes. As dimensões variaram de 1130nm a 17nm, conforme a dimensão (comprimento, largura) considerada. A avaliação da atividade fotocatalítica indicou um comportamento bastante similar ao ZnO comercial utilizado como padrão, o que pode ser explicado pela área superficial e valores de band gap. No entanto, não foi possível encontrar a mesma correlação em outros resultados, sendo então suposto uma fotocorrosão, como fenômeno de degradação da atividade fotocatalítica de ZnO, a exemplo do relatado na literatura por outros autores. / This work investigates nanostructured ZnO particles obtained by the technique of thermal evaporation from zinc metal. Basically, the synthesis occurred in a quartz reactor placed in a muffle furnace, where the zinc metal reacted with an oxidizing atmosphere, provided by the injection of compressed air. Initially, the furnace was heated to temperatures varying from 850 to 1050 º C. Subsequently, the sample of zinc metal was inserted into the heating zone inside the tube, in an amount of 2.5 g, 5g, 10g, 20g and 30g. The injection of argon (99,99% purity) for the transport of ZnO particles out of the reaction zone, occurred with a flow of 1 to 5 L/min. The reaction time was controlled and the regions of occurrence of the reactions varied. Upon completion of the reaction, the furnace was cooled to room temperature to perform the sample collection. The pressure used during the reaction was the atmospheric pressure. The material produced was analyzed to characterize the crystal structure (by x-ray diffraction), morphology (by scanning electron microscopy and transmission, with the help of the software Image Tool for estimation of particle size) and surface area (method BET). The band gap of ZnO was determined by transmittance, reflectance and absorbance analysis using a spectrophotometer with diffuse reflectance accessory, by reflectivity measurements of infrared diffuse in the zinc oxide powder. The absorption data were calculated according to Kubelka-Munk. The photocatalytic activity was evaluated through the degradation process of a solution of methyl orange in a photochemical reactor of UVA light, with its discoloration observed by UV-Visible spectroscopy. The particles of ZnO nanostructured produced had characteristics influenced by the parameters of synthesis. The morphology varied from needle-like forms to tetrapods. The size varied from 1130 nm to 17 nm, depending on the dimension (length, width) considered. The evaluation of photocatalytic activity showed a pattern quite similar to commercial ZnO used as standard, which can be explained by surface area and band gap values. However, we could not find the same correlation in other results, and then assumed a photocorrosion, as a phenomenon of degradation of the photocatalytic activity of ZnO, like the reported in the literature by other authors.

LIMA, Alan Diniz. Lâminas de Irrigação versus Coberturas do Solo e Adubação Borácica na Cultura do Girassol sob as Condições Edafoclimáticas de Russas - Ceará. 2011. 72 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia agrícola, Programa de Pós-Graduação em Engenharia Agrícola, Fortaleza-CE, 2011. / Submitted by demia Maia (demiamlm@gmail.com) on 2016-05-31T16:37:07Z No. of bitstreams: 1 2011_dis_adlima.pdf: 1490275 bytes, checksum: 349372e4ecc166a5a68210f79beb6f94 (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-05-31T16:38:30Z (GMT) No. of bitstreams: 1 2011_dis_adlima.pdf: 1490275 bytes, checksum: 349372e4ecc166a5a68210f79beb6f94 (MD5) / Made available in DSpace on 2016-05-31T16:38:30Z (GMT). No. of bitstreams: 1 2011_dis_adlima.pdf: 1490275 bytes, checksum: 349372e4ecc166a5a68210f79beb6f94 (MD5) Previous issue date: 2011 / The use of sunflower in grain and biodiesel production, makes it potentially important in Brazilian projects of social inclusion. However, to optimize the production of those oilseeds, it is necessary to gather information on certain practices, such as: the association be tween forms of irrigation and soil mulch and the proper fertilization, taking into account the sensitivity of the culture to boron deficiency . That said, this study was aimed at evaluating the effect of the interaction between irrigation and soil mulch cover types, and the effect of boracic fertilization in sunflower cultivation. The work consisted of two experiments, implanted in a randomized complete block design. The experiment 01 was conducted in the split plots scheme consisting of five irrigation dept hs (25, 50, 75, 100 and 125% of class “A” pan evaporation) in the plot and four types of soil mulch (straw rice; carnauba straw, wood shaving and without cover) as subplots with three replications. The experiment 02, also in blocks, consisted of five treat ments and five repetitions with the application of 1, 2, 3, 4 and 5 kg. ha-1 of boron in the conventional manner. All the required cultivation (and phytosanitary) practices were carried. The evaluated variables were: plant height, stem diameter, weight of 1000 seeds, average weight of achenes, achene yield potential, oil content of grain and oil yield potential. The data from the evaluated variables was subjected to analysis of variance by F test, and when significant effects were detected, the effects of qualitative nature were compared using Tukey's test and those of quantitative nature were submitted to regression analysis. In experiment 01, all variables showed statistical inference in the face of irrigation depths, except the oil content. In the same exp eriment, the water depth 807.1 mm (125% CAE) gave a maximum yield of 1634.25 kg ha -1. The potential for oil yield in kg ha -1was significantly affected by irrigation water applied with a maximum of 675.88 kg.ha-1 oil (125% CAE). The average oil content of the seeds was found to be 41.38%. The different soil mulches and the interaction between irrigation depths and soil mulches caused no significant effect on the evaluated variables in experiment 02. On the other hand, the plant height and stem diameter weresignificantly influenced by the levels of boron and by the time of data collection, but not by the interaction rates of boron amount versus collection time. The dose of 4 kg,ha-1 of boron maximized the average mass of seeds (48.95 g), the potential productivity of seeds (2442.34 kg ha-1) and potential oil yield (1076.58 kg ha-1). The average oil content of seeds was found to be 43.49%. / O girassol é integrante de sistemas de produção de grãos e biodiesel, tornando-a uma das culturas com potencial de utilização no Brasil em projetos de inclusão social. Entretanto, para se otimizar a produção dessa oleaginosa, torna-se justificável contornar a falta de informações referentes à alguns tipos de práticas, entre elas: A associação entre irrigação e formas de coberturas do solo, bem como a adubação adequada, dando ênfase ao fato de que a cultura é particularmente sensível a deficiência de boro. Em consequência, este trabalho teve como objetivo avaliar o efeito da interação entre lâminas de irrigação e tipos coberturas do solo, e adubação borácica na cultura do girassol. O trabalho constou de dois experimentos, implantados num delineamento experimental em blocos casualizados. O experimento 01, desenvolvido no esquema de parcelas subdivididas, consistindo de cinco lâminas de irrigação (25, 50, 75, 100 e 125% da evaporação medida no tanque classe “A”) na parcela e quatro tipos de cobertura do solo (palhada de arroz; palhada de carnaúba; raspa de madeira e sem cobertura) na subparcela e três repetições. O experimento 02, também em blocos ao acaso, foi constituído de cinco tratamentos e cinco repetições, com a aplicação de 1, 2, 3, 4 e 5 kg ha-1 de boro, de maneira convencional. Foram procedidos todos os tratos culturais e fitossanitários necessários. As variáveis avaliadas foram: Altura da planta, diâmetro do caule, massa de 1000 aquênios, massa média de aquênios, potencial de produtividade de aquênios, teor de óleo dos aquênios e potencial de produtividade de óleo. Os dados das variáveis avaliadas foram submetidos à análise de variância pelo teste F, e quando verificado efeito significativo, os de natureza qualitativa foram comparados através do teste de Tukey e os de natureza quantitativa foram submetidos à análise de regressão. No experimento 01, todas as variáveis analisadas apresentaram inferência estatística frente às lâminas de irrigação, exceto o teor de óleo, sendo que a lâmina de irrigação 807,1 mm (125% da ECA) proporcionou uma produtividade máxima de 1.634,25 kg ha-1. O potencial de produtividade de óleo em kg ha-1 foi afetado significativamente pelas lâminas de irrigação aplicada com valor máximo de 675,88 kg ha-1de óleo (125% da ECA). O teor de óleo médio de aquênios encontrado foi de 41,38%. As diferentes coberturas do solo e a interação entre lâminas e coberturas do solo não causaram efeito significativo nas variáveis estudadas No experimento 02, a altura de planta e o diâmetro do caule foram influenciados significativamente pelas doses de boro e pela época de coleta dos dados, mas não pela interação doses de boro versus época de coleta. A dose de 4 kg ha-1 de boro maximizou a massa média de aquênios (48,95 g), o potencial de produtividade de aquênios (2442,34 kg ha-1) e o potencial de produtividade de óleo (1076,58 kg ha-1). O teor médio de óleo dos aquênios encontrado foi de 43,49%.

La pomme, fruit le plus cultivé sur le sol français, est principalement menacée par le pathogène Venturia inaequalis, responsable de la maladie de la tavelure qui génère des pertes considérables si elle n'est pas traitée. La politique actuelle de gestions des risques phytopathologiques en France incite à une forte réduction des traitements phytosanitaires tout en maximisant le rendement et la qualité des productions. Dans ce contexte, il apparaît indispensable de mieux comprendre les interactions entre l'arbre, son pathogène, et leur environnement, qui s'articulent pour le cas de la tavelure du pommier autour de la durée d'humectation des feuilles. Au cours de ce travail nous nous sommes intéressés à ce paramètre pour essayer de mieux comprendre les interactions entre microclimat de l'arbre et durée d'humectation. L'étude s'est déroulée en trois étapes majeures : la modélisation de l'évaporation d'une goutte sur un support végétal, l'étude expérimentale de la mouillabilité des feuilles de pommier, et l'étude expérimentale de la variabilité spatiale de la durée d'humectation sous un couvert de pommiers. Ce travail a permis d’expliciter la forte variabilité intra-couronne de la durée d'humectation via la prise en compte de la structure de l’arbre et de la dynamique horaire du microclimat. Le modèle développé, au delà des liens déjà connus entre l’intensité du flux évaporatif et les variables climatiques, a montré la sensibilité importante du temps d’évaporation à la mouillabilité du support via la forme de la goutte d’eau, mettant en avant la nécessité de quantifier au mieux cette interaction goutte support via l’estimation des angles de contact statiques et dynamiques. / Apples, which are the most cultivated fruit in France, are mainly endangered by the fungal pathogen Venturia inaequalis that cause apple scab disease on apple. This disease can be responsible of major products loss unless orchards are treated against apple scab. Nowadays in France, the phytopathological diseases management policies are encouraging growers to reduce considerably the use of pesticides, while keeping a high quality and yield level. In this context, one must understand better how the plant, the pathogen and their environment, interact with each other: for apple scab, the most important environmental parameter is leaf wetness duration. During this work, we studied leaf wetness duration to understand the interactions that occur between the tree microclimate and the wetness duration. To do that we divided our work in three major steps : the modeling of evaporation of a droplet at rest on a leaf, the experimental study of apple leaves wettability, and the experimental study of wetness duration spatial variability within an apple trees orchard. This study led us to clarify the strong intra-crown variability of leaf wetness duration through the consideration of tree structure and hourly dynamics of microclimate. The model we developed, beyond the known links between the evaporative flux intensity and the climatic parameters, showed a strong sensibility of the evaporation duration to the substrate wettability, highlighting the necessity to quantify at best this interaction, through the estimation of static and dynamic contact angles.