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How do mantle plumes help to thin and break up the lithosphere? / Comment un panache mantellique peut-il aider à diminuer la lithosphère ?Agrusta, Roberto 12 December 2012 (has links)
On propose traditionnellement que les panaches mantelliques jouent un rôle important dans l'amincissement de la lithosphère. Des données sismologiques sous Hawaïi et Cape Verde suggèrent une limite lithosphère-asthénosphère (LAB) jusqu'à 50 km plus superficielle qu'autour. Des modèles numériques ont montré, en effet, qu'une convection à petite échelle (SSC, pour small-scale convection) dans la couche à faible viscosité formée à la base de la lithosphère par l'accumulation de la matière des panaches peut être un mécanisme efficace d'érosion du manteau lithosphérique. Cependant, ces modèles montrent que, si la plaque se déplace, l'érosion thermo-mécanique de la lithosphère ne dépasse pas 30 km. Afin de mieux étudier les interactions panache/lithosphère, et d'ainsi caractériser les paramètres contrôlant cette érosion, nous avons effectué des simulations numériques en 2D qui utilisent un modèle pétro-thermomécanique basé sur des approches en différences finies associées à des marqueurs actifs. Nous avons focalisé sur : (1) la dynamique de la SSC dans la couche à faible viscosité formée par étalement du panache à la base de la lithosphère et (2) l'effet de la fusion partielle sur cette dynamique. La plaque lithosphérique et le manteau sous-jacent sont caractérisés par une composition péridotitique homogène à viscosité newtonienne dépendante de la température et de la pression. Une vitesse constante, comprise entre 5 et 12,5 cm/an, est imposée au sommet de la plaque. Les panaches sont créés en imposant une anomalie thermique de 150 à 350 K en base du modèle (700 km de profondeur). La fusion partielle est calculée à partir d'un paramétrization des solidus et liquidus pour la fusion anhydre des péridotites. Nous modélisons la déplétion de la péridotite et son effet sur la fusion partielle en supposant que le degré de fusion ne peut qu'augmenter au cours du temps. Le liquide est accumulé jusqu'à un seuil et la masse fondue en excès est extraite instantanément. La rhéologie de la péridotite partiellement fondue est déterminée utilisant une constitutive relation basée sur un modèle de contiguïté, qui permet de prendre en compte les effets de la distribution de matière liquide à l'échelle de grain. La densité varie en fonction du degré de fusion partielle et de la déplétion du résidu solide. Nous analysons la cinématique du panache lors de son interaction avec une plaque mobile, la dynamique de la convection à petite-échelle (SSC) et le rajeunissement thermique de la lithosphère qui en résulte. Le temps de démarrage et la vigueur de la SSC et, par conséquent, le nouvel état d'équilibre thermique de la lithosphère à l'aplomb du panache dépendent du nombre de Rayleigh (Ra) dans la couche instable à la base de la lithosphère, qui est contrôlé par l'anomalie de température et la rhéologie dans cette couche. Pour des panaches chauds et vigoureux, le démarrage de la SSC ne dépend pas de la vitesse de la plaque. Pour des panaches plus faibles, le temps de démarrage diminue avec l'augmentation de la vitesse de la plaque. Ce comportement est expliqué par une différence dans la structure thermique de la lithosphère, due à des échanges diffusifs à la base lithosphère plus efficaces pour des panaches lents. La diminution de la viscosité associée à la présence de magma et la diminution de la densité du résidu solide accélèrent le démarrage et accroissent la vigueur de la SSC, entraînant une érosion plus efficace et plus proche du point d'impact de panache sous la lithosphère. / Mantle plumes are traditionally proposed to play an important role in thinning the lithosphere. Seismic images beneath Hawaii and Cape Verde, for instance, show a lithosphere-asthenosphere boundary (LAB) up to 50 km shallower than the surroundings. However, previous numerical modeling of plume-lithosphere interaction implies that unless the plate is stationary the thermo-mechanical erosion of the lithosphere does not exceed 30 km. We used 2D petrological-thermo-mechanical numerical models based on a finite-difference method on a staggered grid and marker in cell method to further study the plume-lithosphere interaction. We focused on: (1) analyzing the dynamics of the small-scale convection (SSC) in the plume wake as a function of the plume vigor and plate velocity and (2) quantifying the effect of partial melting on this SSC. A homogeneous peridotite composition with a Newtonian temperature- and pressure-dependent viscosity is used to simulate both the plate and the convective mantle. A constant velocity, ranging from 5 to 12.5 cm/yr, is imposed at the top of the plate. Plumes are created by imposing a thermal anomaly of 150 to 350 K on a 50 km wide domain at the base of the model (700 km depth); the plate right above the thermal anomaly is 40 Myr old. Partial melting is modeled using the batch-melting solidus and liquidus in anhydrous conditions. We model the progressive depletion of peridotite and its effect on partial melting by assuming that the melting degree only strictly increases through time. Melt is accumulated until a porosity threshold is reached and the excess melt is instantaneously extracted. The rheology of the partially molten peridotite is determined using a viscous constitutive relationship based on a contiguity model, which enables to take into account the effects of grain-scale melt distribution. The density varies as a function of the melt fraction and of the depletion of the residue. We analyze the kinematics of the plume as it impacts a moving plate, the dynamics of time-dependent small-scale convection (SSC) instabilities developing in the low-viscosity layer formed by spreading of hot plume material at the lithosphere base, and the resulting thermal rejuvenation of the lithosphere. The onset time and the vigor of SSC and, hence, the new equilibrium thermal state of the lithosphere atop the plume wake depends on the Rayleigh number (Ra) in the unstable layer at the base of the lithosphere, which is controlled by the temperature anomaly and rheology in the plume-fed layer. For vigorous, hot plumes, SSC onset times do not depend on plate velocity. For more sluggish plumes, SSC onset times decrease with increasing plate velocity. This behavior is explained by differences in the thermal structure of the lithosphere, due to variations in the spreading behavior of the plume material at the lithosphere base. Reduction of the viscosity in partial molten domains and decrease in density of the depleted residuum accelerate and enhance the vigor of small-scale convection in the plume-fed low-viscosity layer at the lithosphere base. It also reduces SSC onset times, leading to more effective erosion closer to the plume-lithosphere impact.
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Modely celočíselných časových řad s náhodnými koeficienty / Modely celočíselných časových řad s náhodnými koeficientyBurdejová, Petra January 2013 (has links)
Title: Models of integer-valued time series with random coefficients Author: Petra Burdejová Department: Department of Probability and Mathematical Statistics Supervisor: Doc. RNDr. Zuzana Prášková, CSc. Abstract: In the presented thesis, a generalized integer-valued autoregres- sive process of the order p (GINAR(p)) is considered first. The main aim is taken to introduction of random coefficient integer-valued autoregressive process (RCINAR(p)). We use a thinning operator in order to define the processes. The main characteristics of GINAR(p) and RCINAR(p) are obtained. Condi- tions for stationarity and ergodicity are stated. Three methods of estimation (Yule-Walker, Conditional least squares, Generalized method of moments) are given and compared in simulation with respect to the mean squared error (MSE). At the end, RCINAR(3) model is applied to a real dataset representing a number of earthquakes per year. Keywords: thinning operator, random coefficients, integer-valued time se- ries, GINAR, RCINAR
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Análise quantitativa e qualitativa do crescimento de caixeta - Tabebuia cassinoides (LAM.) DC. - em florestas manejadas, no município de Iguape/SP. / Quantitative and qualitative analysis of the growth caixeta tabebuia cassinoides (lam.) dc. in forest handeled in the municipal district of Iguape/SP.Bernhardt, Ricardo 22 October 2003 (has links)
A caixeta - Tabebuia cassinoides (LAM.) DC. - é uma espécie que ocorre nas planícies de inundação da Floresta Atlântica. Seu uso comercial iniciou na década de 30, principalmente para a produção de tamancos e lápis. A exploração da caixeta foi proibida em 1989, pela Portaria IBAMA n o 218. Em função da sua importância para as comunidades e da pressão exercida pelas mesmas, o manejo foi regulamentado em 1992, pela Resolução SMA 11, da Secretaria do Meio Ambiente do Estado de São Paulo. A Resolução regulamenta o manejo da caixeta sob regime de rendimento auto sustentado. O ciclo de corte foi estabelecido em 12 anos, porém não se baseou em informações técnico-científicas. As informações sobre o crescimento e produtividade de florestas tropicais são escassas e essenciais para verificar a sustentabilidade técnica, ambiental e econômica do manejo florestal. Dessa forma, a checagem do ciclo proposto é fundamental para garantir a sustentabilidade do manejo da caixeta. Como a caixeta emite vigorosa brotação após a colheita, uma das principais práticas silviculturais pós-colheita é a desbrota. A Resolução SMA 11/92, estabelece que devem ser deixados de 1 a 3 brotos por cepa.. Com o objetivo de verificar o crescimento e qualidade de fuste em função da quantidade de brotos foi estabelecido um experimento com 224 cepas. A partir do acompanhamento do Inventário Florestal da Fazenda Retiro (50 parcelas 10 x 20m) e Fazenda Cindumel (46 parcelas 10 x 20m), observou-se Incremento Médio Anual (IMA) de 3,215 ± 0,366 m 3 /ha/ano e 5,557 ± 0,598 m 3 /ha/ano, respectivamente. Analisando a intensidade de colheita das áreas observou-se que a mesma foi superior a 50% do volume de madeira passível de colheita e que nas áreas próximas às rotas de extração a intensidade foi maior, chegando a 94%. Isto acarretou numa redução de até 54% do IMA, para as áreas em que a intensidade de colheita foi superior a 75%. Com as estimativas do IMA foi estimado o Intervalo de Confiança para o ciclo de colheita, que variou de 12,9 a 17,6 anos. O acompanhamento do experimento de desbrota, 8 anos após a colheita, indica que os tratamentos em que foram deixados 1 e 2 brotos não diferem estatisticamente entre si e apresentam diâmetro médio das brotações de 8,95 cm e 8,37 cm, respectivamente. Enquanto os tratamentos em que foram deixados 3 e todas os brotos apresentam diâmetro médio de 7,30 cm e 5,37 cm, respectivamente. A aplicação da desbrota melhorou significativamente a qualidade de fuste, aumentando a altura da 1 a bifurcação e reduzindo a tortuosidade em todos os tratamentos, quando comparada ao tratamento testemunha. Os resultados de pesquisa apontam para a necessidade de revisão da Resolução SMA 11/92, para garantir a sustentabilidade do manejo da caixeta, nos seguintes aspectos: (i) estabelecimento de um limite para a intensidade de colheita, de até 75% nas áreas próximas às rotas de extração; (ii) o número de brotos a ser deixado por cepa deve ser de 1 a 2, e; (iii) o ciclo colheita de 12 anos é subestimado. / Caixeta - Tabebuia cassinoides (LAM.) DC. - is a tree species of swamp forests in the Atlantic Rain Forest. It has been used since the 30s, mainly for clog and pencil production. IBAMA Decree no. 218 prohibited Caixetas explotation in 1989. By its importance for the community and social movement, caixetas management was regulated by the Resolution 11/92 by the Environmental Secretary of São Paulo State. This Resolution regulates caixeta management by auto-sustained regime. The cutting cycle was defined as 12 years, but isnt based on technical and scientific data. Information about growth and yield are rare for Tropical Rain Forest. This information is essential to verify technical, environmental and economic sustainability of the forest management. Thus, check the proposed cutting cycle is fundamental to certify the sustainability of caixeta management. After harvest caixeta sprouts vigorously, so one the most important silvicultural practice is sprout thinning. Resolution ES 11/92, establishes that must be left 1 to 3 sprouts per stump. Objectifying to verify growth and stem quality of the sprouts was established an experimental area composed by 224 stumps. By the Forest Inventory measurement of Retiro Farm (50 samples 10 x 20 m) and Cindumel Farm (46 samples 10 x 20 m), was observed Mean Annual Increment for volume of 3,215 ± 0,366 m 3 /ha/year and 5,557 ± 0,598 m 3 /ha/year, respectively. The harvest intensity was over 50% of the amount harvestable wood; the intensity was higher near the extraction routes, reaching 94%. Thus caused a reduction of 54% in MAI, where the harvest intensity was higher than 75%. The estimated harvest cycle for managed caixetais has Confident Interval from 12,9 to 17,6 years. The measurement of thinning sprout experiment, 8 years after logging, indicates that treatments that have 1 and 2 sprouts are statistically equal, and have mean DBH of 8,95 cm and 8,37 cm, respectively. While the treatments that have 3 and all sprouts have mean DBH of 7,30 cm and 5,37 cm, respectively, for the same period. Sprout thinning improves stem quality, increasing the height of first fork and reducing stem sinuosity, when compared with sprouts without thinning. The research results pointed to the need of Resolution 11 review, searching for the sustainability of caixeta management. The points that must be reviewed, are: (i) establishment of a limit of harvest intensity lesser than 75%, nearby the extraction routes; (ii) the number of the sprouts per stump must be 1 or 2, and; (iii) the harvest cycle of 12 years is underestimated.
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Influência do desbaste e da adubação na qualidade da madeira serrada de Eucalyptus grandis Hill ex-Maiden. / Influence of thinning and fertilization on Eucalyptus grandis (Hill ex-Maiden) sawn wood quality.Lima, Israel Luiz de 18 May 2005 (has links)
O presente trabalho teve como objetivo geral estudar a influência do manejo florestal no rendimento e na qualidade tecnológica da madeira serrada de uma população plantada de Eucalyptus grandis, de 21 anos de idade, manejada pelo sistema de desbastes seletivos com aplicação de fertilizantes na época do início dos desbastes. Os fatores utilizados foram três intensidades de desbastes seletivos (37, 50 e 75%), presença ou ausência de fertilizantes, três classes de diâmetro e três posições verticais ao longo da altura do fuste comercial.As influências dos fatores e de suas combinações nas tensões de crescimento das árvores foram avaliadas de forma indireta através das rachaduras de extremidade de tora, rachadura de extremidade de tábua úmidas e secas, encurvamento e arqueamento de tábua úmida e deslocamento da medula em relação à sua normal posição central. Foram avaliadas, também, porcentagem de casca e conicidade de toras, que são variáveis que interferem no rendimento em madeira serrada; massa específica da madeira à umidade de equilíbrio ao ar; módulo de elasticidade estrutural na flexão estática não destrutiva, determinado em tábuas secas de dimensões comerciais e um sistema de classificação de tábuas segundo diferentes classes de qualidade. O deslocamento da medula, conicidade, porcentagem de casca e o índice de rachaduras de topo de tora não sofreram nenhuma influência significativa dos fatores desbaste, adubação e classe de diâmetro. As rachaduras de extremidade de tábua serrada seca ou verde, encurvamento, arqueamento e o módulo de elasticidade estrutural sofreram influências dos fatores desbaste, adubação e classe de diâmetro em algumas situações específicas. O índice de rachadura de tábuas serrada verde ou seca diminui da medula para a casca enquanto que o encurvamento de peça serrada e o módulo de elasticidade estrutural aumentam da medula para a casca. O arqueamento das tábuas não apresenta nenhuma tendência de variação ao longo do raio da tora. A metodologia não destrutiva utilizada para avaliação do módulo de elasticidade estrutural à flexão estática demonstrou-se ser simples, prática e eficiente.Na classificação das tábuas serradas foi constatado que a posição relativa da tábua no raio interfere nas classes de qualidade da madeira. A freqüência de tábuas de 1ª classe aumenta da medula para a casca enquanto que as tábuas de refugo diminuem da medula para casca. A massa específica da madeira à umidade de equilíbrio ao ar sofreu influência do fator adubo e aumenta significativamente da medula para a casca. A intensidade de 75% de desbaste propiciou, de maneira geral, maior homogeneidade de qualidade da madeira ao longo do raio. Observa-se boas relações positivas entre rachadura de tábua seca e rachadura de tábua verde, mas a melhor relação foi observada entre o rendimento em madeira serrada seca e o rendimento em madeira serrada verde com destopo. / The study had the general objective of studying the influence of forest thinning on the some yield and technological quality indicators of sawn wood from a 21 year old grown Eucalyptus grandis stand managed by selective thinning with the use of fertilizers at 6 years old. The thinning intensities (37, 50 and 75%), presence or absence of fertilizers, two diameter classes, two vertical positions along the stem commercial height and three longitudinal position along the tree radius were taken as the study factors. The influences of the factors treatments and their combinations on tree growth stresses were evaluate indirectly through log end splitting, green and dry sawn lumber end splitting, green sawn lumber bow and spring and pith displacement from it normal central position. The percentage of bark and log taper which are variables that interfere on the sawn wood yield was also evaluated. Structural modulus of elasticity at static bending determined in commercial dimensions dry sawn lumber and a grading system of sawn pieces were determined. Thinning and fertilization had no significant effect on pith displacement, log tapering, bark percentage and log end splitting index. Green and dry sawn lumber, bow, spring and structural modulus of elasticity were influenced by thinning, fertilization and diameter class in some specific situations. Green or dry sawn lumber end splitting index decreases from pith to bark although green sawn lumber bow and the structural modulus of elasticity increase toward the periphery of the tree. Green lumber spring presents no variation tendency along the log radius. The methodology of non-destructive testing used for structural modulus of elasticity evaluation at static bending had demonstrated to be simple, practical and efficient. It was observed during sawn lumber grading operation that the relative position of a piece in the tree radius interferes on its class grade. The frequency of first class lumber increases from pith to bark while the refused pieces number decreases toward the outer part of the tree. In general the 75% thinning intensity slightly promoted a better homogeneity of sawn wood quality along the tree radius.
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Comparação de métodos de raleio manual, químico e mecânico de frutos / Comparação de métodos de raleio manual, químico e mecânico de frutos / Comparison of hand, chemical and mechanical thinning methods for fruit. / Comparison of hand, chemical and mechanical thinning methods for fruit.Pavanello, Alexandre Pozzobom 10 June 2016 (has links)
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Previous issue date: 2016-06-10 / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná / The harvest of fruits of high quality provides increased market value for the fruit grower. A effective fruit thinning is of the most important steps to provide good commercialization. The increased occurrence of hail storms during the growing period resulted in the installation of protective hail nets. This study aimed to evaluate the effects of chemical and mechanical thinning in plums and hand, chemical and mechanical thinning in apples for different hail nets.. For thinning in plums, mechanical thinning was more efficient when compared to chemical thinning. The mechanical thinning treatment reduced fruit set, number of fruit per tree and yield, however it increased fruit size, fruit weight and promoted higher vegetative growth, an important factor to avoid alternating production every year. For apple thinning, mechanical thinning was an effective fruit thinner. It was observed that some treatments like CT-BA required around 300 hours or more per hectare of hand thinning to achieve a satisfactory thinning efficacy. The black hail nets showed a reduction in red colour in apples. The thinning efficacy value (TEV) for hand thinning was 93%, for mechanical thinning was 74%, for chemical thinning with Metamitron was 62% and for chemical thinning with Benzyladenine was 54%. / A colheita de frutos com qualidade proporciona ao produtor agregar valor na venda da fruta. Realizar o raleio dos frutos de maneira eficiente é uma das práticas que proporcionam ao fruticultor melhorar a rentabilidade na produção. Devido as frequentes chuvas de granizo no período de produção de frutas, alguns fruticultores optam por implantar telas antigranizo. Neste contexto, os objetivos deste trabalho foram avaliar os efeitos do raleio químico e mecânico em ameixeira e do raleio manual, químico e mecânico em macieiras sobre diferentes telas antigranizo. Para os raleios em ameixeira, os tratamentos com raleio mecânico foram mais eficientes comparados aos tratamentos com raleio químico. O raleio mecânico reduziu o pegamento de frutos, o número de frutos e a produtividade. Entretanto, proporcionou aumento no tamanho e peso dos frutos e maior crescimento vegetativo, o que pode evitar a alternância de produção. Para o raleio em macieiras, o raleio mecânico foi o mais efetivo. Para o tratamento com benziladenina, foram necessárias mais de 300 horas por hectare de raleio manual para alcançar um raleio eficaz. A utilização de tela preta proporciona redução na coloração vermelha dos frutos de maçã. O Valor da Eficácia do Raleio (VER) para o tratamento com raleio manual foi de 93%, com raleio mecânico de 74%, com raleio químico Metamitron de 62% e o raleio químico Benziladenina 54%.
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Predator effects on behaviour and life-history of preyBrodin, Tomas January 2005 (has links)
<p>In this thesis I investigate predator-induced effects on behavioural and life-history characteristics of prey. At any moment a given predator is capable of attacking a small number of prey. However, the mere presence of a predator may impact a much larger number of individuals, as prey implement various behavioural and developmental mechanisms to reduce the risk of predation. It has become increasingly clear that predator induced responses have the potential to affect patterns of species abundance and distribution as well as individual fitness of prey. I study these responses by incorporating field surveys, semi-field experiments and laboratory experiments. All experiments were done in an aquatic environment using fish or large odonate larvae as predators and damselfly-or diving beetle larvae as prey.</p><p>My work highlights the importance of monitoring prey behaviour when studying life-history characteristics. I show that fish presence is an important factor for determining species abundance and distribution of odonates, and that prey behaviour may be a good predictor for fish vulnerability. Larval damselflies react behaviourally to predator presence by reducing activity and/or restricting habitat use. I confirm that such anti-predator responses have positive effects on prey survival in the presence of a predator but negative effects on growth and development of prey. In addition, my results suggest that the increase in per capita food resources for surviving prey following a predation episode (i.e. thinning) can have a stronger positive effect on prey growth and development than the negative effect of anti-predator responses. I also show that the strength of an anti-predator response is dependent on resource availability of the prey, with prey responding less strongly when resources are scarce. My results also indicate that the strength of the anti-predator response of damselfly larvae depends on predator diet and larval age. Predators feeding on prey conspecifics induce a stronger behavioural response in young larva than predators that feed on prey heterospecifics do. This diet-effect was not found in larvae late in ontogeny, due to an increased activity of larva where predators consumed damselflies. Such increased larval activity can be explained as a reaction to a time-constraint. Finally, I found that activity of damselfly larvae is genetically determined and that this has lead to a behavioural syndrome that might limit larval plasticity to a certain activity-range. This phenomenon may have implications for how well larvae are able to react to both biotic and abiotic changes in the environment.</p>
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Predator effects on behaviour and life-history of preyBrodin, Tomas January 2005 (has links)
In this thesis I investigate predator-induced effects on behavioural and life-history characteristics of prey. At any moment a given predator is capable of attacking a small number of prey. However, the mere presence of a predator may impact a much larger number of individuals, as prey implement various behavioural and developmental mechanisms to reduce the risk of predation. It has become increasingly clear that predator induced responses have the potential to affect patterns of species abundance and distribution as well as individual fitness of prey. I study these responses by incorporating field surveys, semi-field experiments and laboratory experiments. All experiments were done in an aquatic environment using fish or large odonate larvae as predators and damselfly-or diving beetle larvae as prey. My work highlights the importance of monitoring prey behaviour when studying life-history characteristics. I show that fish presence is an important factor for determining species abundance and distribution of odonates, and that prey behaviour may be a good predictor for fish vulnerability. Larval damselflies react behaviourally to predator presence by reducing activity and/or restricting habitat use. I confirm that such anti-predator responses have positive effects on prey survival in the presence of a predator but negative effects on growth and development of prey. In addition, my results suggest that the increase in per capita food resources for surviving prey following a predation episode (i.e. thinning) can have a stronger positive effect on prey growth and development than the negative effect of anti-predator responses. I also show that the strength of an anti-predator response is dependent on resource availability of the prey, with prey responding less strongly when resources are scarce. My results also indicate that the strength of the anti-predator response of damselfly larvae depends on predator diet and larval age. Predators feeding on prey conspecifics induce a stronger behavioural response in young larva than predators that feed on prey heterospecifics do. This diet-effect was not found in larvae late in ontogeny, due to an increased activity of larva where predators consumed damselflies. Such increased larval activity can be explained as a reaction to a time-constraint. Finally, I found that activity of damselfly larvae is genetically determined and that this has lead to a behavioural syndrome that might limit larval plasticity to a certain activity-range. This phenomenon may have implications for how well larvae are able to react to both biotic and abiotic changes in the environment.
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Detection and elimination of defects during manufacture of high-temperature polymer electrolyte membranesBhamidipati, Kanthi Latha 02 March 2011 (has links)
Defect generation and propagation in thin films, such as separation membranes, can lead to premature or catastrophic failure of devices such as polymer electrolyte membrane fuel cells (PEMFC). It is hypothesized that defects (e.g., air bubbles, pin-holes, and holes) originate during the manufacturing stage, if precise control is not maintained over the coating process, and they propagate during system operation. Experimental and numerical studies were performed to detect and eliminate defects that were induced during slot die coating of high-viscosity (1 to 40 Pa-s), shear-thinning solutions. The effects of fluid properties, geometric parameters and processing conditions on air entrainment and coating windows (limited set of processing conditions for which defect-free coating exists) were studied. When smaller slot gaps and coating gaps were used, relatively small bubbles were entrained in the coated film. The air bubble sizes increased as the viscosity of the coating solution decreased. A semi-empirical model correlating the maximum coating speed to a solution's material properties, geometric parameters and processing conditions was developed. Such a predictive model will enable engineers to determine the maximum coating boundary for shear-thinning and Newtonian solutions within certain constraints. Smaller coating gaps and low-viscosity solutions produced higher coating speeds. The surface tension property of the coating solution provided stability to the coating bead. Therefore, solutions with higher surface tension could be processed at higher coating speeds.
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Backyard Fruit Production at Elevations 3500 to 6000 FeetYoung, Deborah, Call, Robert E, Kilby, Michael, DeGomez, Tom 03 1900 (has links)
Revised; Originally Published: 2000 / 7 pp. / The mid elevations (3,500 to 6,000 feet) in Arizona can be ideal for growing tree fruit. Site selection can make a pronounced effect on how well fruit will grow and produce. The warmer the site the greater the chance of success. Areas where cold air settles are a poor choice for tree fruit production. Variety selection is very important for good fruit production.February and March are the best months to plant bare root trees, although they can be planted anytime during the dormant season. Try to plant 30 days before bud break. Containerized plants are best planted in late September through early October. The open center pruning system allows for more sunlight to reach all the branches of the tree. Whereas the central leader is used with those trees that are less vigorous. Training trees when young is an important step in ensuring a strong scaffold system when bearing. Fruit thinning helps to control fruit size and consistent bearing. Proper fertilization, irrigation, and pest control will promote healthy productive trees.
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Role of hyperextension for the formation of rift systems and its implication for reactivation processes and orogen formation : the example of the Bay of Biscay and PyreneesTugend, Julie 28 November 2013 (has links) (PDF)
Knowledge on lithosphere extensional mechanisms has greatly benefited from studies made both at presentday rifted margins and onshore fossil analogues. Nevertheless, the spatial and temporal evolution of the processes leading to continental break-up and oceanic crust formation remains poorly constrained. The Bay of Biscay and Pyrenees is used in this study as a natural laboratory to investigate the formation and reactivation of rift systems. A new offshore-onshore approach is developed and applied to identify, characterize and map the rift domains inherited from the Bay of Biscay opening and partly integrated into the Pyrenean orogen. This mapping reveals the complex architecture of European-Iberian plate boundary resulting from a strongly polyphased evolution. Several rift systems spatially distinct are preserved at different evolutionary stages. An important segmentation partially inherited from the pre-rift structuration controls the formation of the rift systems, an observation that has important implications for regional kinematic restorations. Several steps in compressional deformation can be distinguished and related to the rift inherited architecture. Reactivation is initiated in the exhumed mantle domain. Following the subduction of hyperthinned crust, continental collision processes are controlled by the proximal and necking domains acting as buttresses. These results emphasize the role of pre-rift inheritance for the spatial evolution of rift systems and the importance of the rift-related architecture to unravel the formation of collisional orogen.
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