La synthèse et le transport du carbone chez le pommier repose sur un ensemble de mécanismes complexes et imbriqués dépendants de facteurs endogènes et exogènes. Uneapproche combinant une caractérisation écophysiologique et l’utilisation d’un modèle structure-fonction de la plante (Functional-Structural Plant Model, FSPM) présente un moyenintéressant pour ce champ de recherche dans la mesure où un modèle structure-fonction permet d’intégrer la topologie et la géométrie de la plante et de ses différents organes à l’ensemble des facteurs impliqués dans l’assimilation et le transport du carbone et de l’eau. Le travail présenté ici a contribué à la compréhension des relations sources-puits mais égalementà l’élaboration d’un modèle FSPM à plusieurs niveaux. Premièrement, le développement de modèles de prédiction de l’architecture des différentes pousses du pommier à partir de variables simples apporte un moyen novateur pour simplifier la simulation de l’architecturedes branches mais égalementpour quantifi er de façon robuste la surface foliaire. Deuxièmement,l’établissement d’un réseau de corrélations entrevariables morphométriques des différents organes issus dubourgeon mixte met en évidence les organes les plus connectésà l’échelle du spur. Enfi n, une étude des relations sourcespuitsà l’échelle de la branche a permis, d’une part, une caractérisationde la régulation de la photosynthèse nette desfeuilles en réponse à des changements dans le ratio sources/puits mais aussi en fonction des types de feuilles et, d’autrepart, à mettre la lumière sur l’infl / The synthesis and the transport of carbon in apple are basedon a whole host of complex and interlaced mechanisms thatdepend on endogenous and exogenous factors. An approachthat combines the ecophysiological characterisation with theuse of a Functional-Structural Plant Model (FSPM) representsan interesting method in this fi eld of research, inasmuch assuch an FSPM allows integrating the topology and the geometryof the plant and its constituting organs with the entiretyof factors involved in assimilation as well as water andcarbon transport. The present study has contributed to thebetter understanding of the source-sink relations characterizingthis system but also to the elaboration of a multi-scaledFSPM. First, the development of models for the prediction ofthe architecture of different shoot types in apple from simplevariables provides a novel way to simplify the simulationof theinitial structure of branches but also to quantify leaf area in arobust manner. Second, the creation of a network of correlationsamong morphometric variables of the different organsformed by the mixed bud of apple clearly shows the functionalrelations among the spur organs. In the end, the study ofsource-sink relations at the branch scale has allowed, on theone hand, to characterize the regulation of net photosynthesisas a function of a changed source/sink ratio but also asa function of leaf type and, on the other hand, to shed somelight on the infl uence that the competition among fruits hason increasing sink strength and thus regulating the leaf

Doctor of Philosophy / Department of Agronomy / Tesfaye Tesso / Sweet Sorghum [Sorghum bicolor (L.) Moench] is a type of cultivated sorghum grown primarily for its sugar-rich stalks. Because of its high fermentable sugar content, the crop is widely recognized as an alternative feedstock source for bio-fuel production. The extent to which stalk sugar accumulation occurs may be determined by several factors including the sink size. Grain is the most important sink in sorghum and other grain crops. Three experiments were conducted in this study to determine the extent to which the grain sink can reduce sugar accumulation in the stalks, to test and validate a genetic system that allows development of sterile sweet sorghum hybrids, and to assess the potential of sugar-rich hybrids to overcome stalk rot diseases. The first experiment, based on 22 sweet sorghum genotypes, was undertaken to study the effect of eliminating the grain sink (removing the head prior to anthesis) on stalk juice yield, sugar accumulation, and biomass. The data showed that the grain sink had a significant effect on all traits measured. Elimination of the grain sink significantly increased oBrix % (17.8%), dry biomass (27.8%), juice yield (23.9%), and total sugar yield (43.5%). The second experiment was aimed at validating the role of A3 genetic male sterility system for producing sterile sweet sorghum hybrids. Ten sweet sorghum pollinator lines of variable sugar content were selected among the entries included in the previous experiment. The lines were crossed to four A1 and A3 cytoplasmic male sterile (CMS) lines using a Design II mating scheme. The A3 females did not have effective restorers so that the hybrids were expected to be sterile. The parental lines and corresponding hybrids were evaluated for biomass production, oBrix, juice and sugar yield using a randomized complete block design. All A3 hybrids were sterile and did not produce seed when heads were covered prior to pollination. The effect of grain sink represented by the A1 vs. A3 CMS were highly significant for Brix%, biomass, juice, and sugar yield. Comparison of parents vs. crosses component was highly significant, indicating marked heterosis effect for the traits. Both general (GCA) and specific (SCA) combining ability effects were also significant for all traits, indicating the role of both additive and dominance genetic effects in the inheritance of the characters. Earlier studies have shown positive relationships between stalk sugar concentration and stalk rot disease resistance in sorghum. Thus, the objective of the third experiment was to study the effects of the CMS mediated differential accumulation of stalk sugar on severity of charcoal rot disease caused by Macrophomina phaseolina. The experiment provided an opportunity to test the effect of variable stalk sugar in the same genetic backgrounds. The data indicated that hybrids produced from A3 cytoplasm were more resistant to charcoal rot (7.1cm lesion length) compared to those produced from the A1 hybrids (9.5 cm lesion length). The enhanced resistance of hybrids with higher sugar yield could have significant agronomic advantage in sugar based bio-fuel feedstock production.

The demand for smaller but more powerful electronic components is ever increasing. This demand puts a strain on engineers to produce optimal cooling designs for these electronic components. One method for cooling these electronic components is with heat sinks which effectively increase the surface area available for extracting the heat from the electronic components. Computational Fluid Dynamics (CFD) software is sometimes used to aid in the design process, but CFD simulations are computationally expensive and take long to complete. This causes the design engineer to test only a few proposed designs based on his/her experience and select the design that performs the best out of the tested designs, which might not be the optimum. The temperature distribution inside the heat sink can be solved relatively quickly with the diffusion equation, but the flow around the heat sink complicates the CFD simulation and increases the solving time significantly. Therefore, applications have been developed where the interaction between the heat sink and the flow around the heat sink is replaced by heat transfer coefficients. These coefficients are calculated from correlated equations which contain the flow properties. The flow properties are extracted from a flow network solver, which solves the flow around the heat sink. This procedure results in less expensive simulations, which can be used together with an optimisation procedure to develop an optimum cooling design. In this dissertation, a correlation for the contraction heat transfer coefficients of rectangular pin fin heat sinks was developed. A methodology was developed where consecutive regression lines were fitted to a large set of data extracted from numerous CFD simulations. The combination of these regression lines formed the basis of the correlation, which was divided into two correlations; one for laminar flow and another for turbulent flow. The correlations were tested against CFD simulations as well as experimental data. The results indicate that these correlations can be effectively used to calculate the contraction heat transfer coefficients on pin fin heat sinks. / Dissertation (MEng)--University of Pretoria, 2011. / Mechanical and Aeronautical Engineering / unrestricted

La septoriose (pathogène Zymoseptoria tritici) est la plus importante maladie foliaire des cultures de blé en Europe. Les méthodes de lutte comprennent la résistance variétale, les stratégies d’évitement de la maladie et le recours aux fongicides. Cependant, ces stratégies n’assurent pas une protection complète des cultures de blé. La tolérance à la septoriose est une approche complémentaire qui vise justement à maintenir le rendement en présence de symptômes. La tolérance à la septoriose dépend de traits physiologiques de la plante et d’équilibres source/puits : la demande des puits (croissance des grains) doit être satisfaite malgré une disponibilité réduite des sources (capacité photosynthétique réduite par les symptômes foliaires). La surface verte du couvert, la sénescence et les composantes du rendement sont des traits potentiels de tolérance intéressants qui ont été étudiés lors de ce projet. Une étude de datamining, une expérience en serre et deux expériences au champ ont été menées pour fournir des informations complémentaires sur les mécanismes de tolérance à la septoriose. Les effets des interactions génotype × environnement sur les traits de tolérance ont été étudiés pour deux saisons × cinq localisations × neuf cultivars. La nutrition azotée et le métabolisme de quatre lignées double-haploïdes (DH, contrastées du point de vue de leur tolérance à la septoriose) ont été examinés dans une expérience en conditions contrôlées à l'UMR ECOSYS (INRA, AgroParisTech Grignon, France). Les bilans source/puits de six lignées DH contrastant pour la tolérance ont également été examinés en fonction de leurs réponses à un traitement d'égrainage, appliqué dans une expérience au champ à Hereford (Royaume-Uni). Enfin, une expérience au champ avec deux stratégies fongicides (contrôle total des maladies / lutte contre les maladies non-ciblées) a permis d’étudier la tolérance à la septoriose de six cultivars modernes (Leicestershire, Royaume-Uni). L'objectif principal était de vérifier les traits potentiels de tolérance à la septoriose sur des cultivars actuellement commercialisés. Des traits potentiels de tolérance à la septoriose ont été identifiés tels que la date d’épiaison, le faible degré de limitation des puits par les sources lors de la phase de remplissage du grain des couverts sains, la distribution verticale des surfaces foliaires favorisant des feuilles supérieures relativement grandes. Les résultats ont montré que ces caractères pourraient être sélectionnables, sans compromis avec le rendement potentiel. Enfin, le projet a également discuté du besoin de méthodes alternatives de quantification de la tolérance du blé à la septoriose, ainsi que de l'importance des variations environnementales qui doivent être prises en compte pour étudier les variations génétiques de la tolérance, mais qui pourraient également être utilisées pour identifier des environnements tolérants. / The Septoria tritici blotch disease (STB, pathogen Zymoseptoria tritici) is the most damaging foliar infection of wheat crops in Europe. Disease management strategies include cultivar resistance, disease escape strategy and fungicides. However, these strategies have failed to provide a complete protection of wheat crops. The STB tolerance is a complementary approach which aims to maintain yield in the presence of the symptoms. The tolerance of STB relies on plant physiology and source/sink balance: the sink demand (the grain growth) must be satisfied in spite of reduced source availability (photosynthetic capacity as affected by the STB symptoms on the leaves). The green canopy area, the senescence timing and the grain yield components are interesting potential sources of tolerance that were studied in this project. A data-mining study, one glasshouse experiment and two field experiments were carried out providing complementary insights on STB tolerance mechanisms. The genotype × environment interaction effects on tolerance traits were investigated for two seasons × five locations × nine cultivars datasets. The nitrogen nutrition and metabolism of four doubled-haploid (DH) lines contrasting for STB tolerance were examined in a controlled-glasshouse experiment at UMR ECOSYS (INRA,AgroParisTech) Grignon, France. The source/sink balance of six DH lines contrasting for STB tolerance was also examined according to their responses to a spikelet removal treatment, applied in a field experiment in Hereford, UK. Finally, a field experiment with two fungicide regimes (full disease control and non-target (STB) disease control) probed the STB tolerance of six modern UK winter wheat cultivars in Leicestershire, UK. The main objective was to verify identified potential STB tolerance traits in commercial cultivars. Putative STB tolerance traits have been identified such as the early heading date, the low degree of grain-source limitation of healthy crops during the grain filling phase, the vertical canopy distribution favouring a relatively larger flag-leaf. Results showed these traits might be selectable in wheat breeding without a trade-off with the potential yield. Finally, the project also discussed the need for alternative STB tolerance quantification methods, as well as the importance of environmental variations which have to be taken into account to study genetic variation in tolerance, but which could also be used to discriminate tolerant environment.

Philosophiae Doctor - PhD / The tripartite symbiosis between Phaseolus vulgaris, arbuscular-mycorrhiza and the nodule bacteria, Rhizobia have been the focus of many studies ranging over a number of decades, however these studies have failed to answer certain questions relating the role of the symbionts in regard to host nutrition and the subsequent influence of these symbionts on the host C- economy. There is little doubt over the synergistic benefits involved in the dual inoculation of bean plants, as well as the resultant C-costs of maintaining the 2 symbionts, yet the specific contribution of the individual symbionts to the hosts overall nutrient and C-economy remain to be clarified. Thus the aim of this thesis is to help clarify these points by determining the symbiont induced photosynthetic, respiratory and nutritional changes taking place in the host. This was achieved by a series of experiments in which nodulated bean plants were split into two categories-those with and without AM colonized roots. These plants were then exposed to a range of growing conditions, including hi and low P, and a series of N treatments, ranging from zero N through to 3 mM NH/. Under these differing nutrient conditions growth, photosynthetic, respiratory, nutrient and amino acid responses were monitored, thus allowing for the determination of the symbionts influence on the host and the hosts reliance on the respective symbionts. Host reliance was noted most strongly under nutrient limiting conditions. Under low P treatment AM was the dominant symbiont as far as host C was concerned, allowing for the early establishment of the AM, thus ensuring the uptake of P for both host and nodule development. High P affected AM colonization to a greater extent than it did nodule dry weight and conversely the addition of N~ + led to a greater decrease in nodule dry weight than it did AM colonization. In spite of this decline, AM benefited the host by improving host N nutrition and relieving N-feedback inhibition of the export amino acid asparagine on BNF. These AM induced benefits did come at a cost to the host though, the dual inoculated plants had higher below ground respiratory costs and subsequently higher photosynthetic rates to compensate for the increased demand for C. The higher photosynthetic rates associated with dual inoculation were as a result of symbiont induced sink stimulation and not due to the improved nutrition of the host, as shown by the photosynthetic and nutrient response ratios. However, the respiratory costs associated with the uptake of soil nutrients were lower in AM colonized roots, thus showing an increased efficiency in nutrient gain by AM colonized roots. This improvement in host N nutrition as a result of AM colonization, coupled with the lower respiratory costs of AM nutrition led to the conclusion that under certain growing conditions nodules can become redundant and possibly parasitic.

<p>Heat sinks have the capability of increasing operating heat flux limits for improved thermal management in the immersion cooling of electronics using dielectric fluids. However, even for arrays of simple, straight fins, the generation of vapor between and along fins during pool boiling lead to performance effects that are not well understood. Further investigation of the heat-flux-dependent variation of boiling modes that can manifest along the fin height is required. Although methods for the prediction of fin boiling heat transfer exist that incorporate a variable heat transfer coefficient determined from a flat surface, they have been developed and assessed for single, isolated fins under the assumption that the sides of the fin at any location behave like that of a flat surface. As a result, when applied to fin arrays, these methods may not always be accurate for the full range of heat flux operation along boiling curve up to the critical heat flux, due to the fins interfering with each other when arranged in arrays of differing spacing and height. To establish when the fins in an array can be described as isolated and having the flat surface boiling behavior, pool boiling experiments are performed using copper heat sinks in two fluids with vastly different properties: HFE-7100 and water. The spacing and height of the longitudinal fins are varied across a range from much larger to less than half of the scale of the capillary length scale of both fluids, <em>L</em>_<em>b</em>. High-speed visualizations enable the identification of different boiling regimes to identify correspondence between flow observations and the boiling performance, such as when there is bubble confinement from fin interference. Trends in the pool boiling data are also compared, noting changes in superheat at various heat fluxes to establish when fin height or spacing affects boiling behavior. The experimental boiling performance is compared to predictions developed assuming isolated fins so as to identify the spacings and heights for which the fin arrays follow this behavior. Overall, the data from both fluids strongly support a hypothesis that <em>L</em>_<em>b</em> is the key length scale. Heat transfer from fin array heat sinks with heights and spacings above <em>L</em>_<em>b</em> are shown to be accurately predicted in both fluids. However, spacings smaller than <em>L</em>_<em>b</em> lead to bubble confinement which affects the superheat, particularly at low heat fluxes, while heights shorter than <em>L</em>_<em>b</em> are unable to support multiple boiling regimes along the fin sidewall. This work identifies the capillary length as the key length scale at which confinement and height effects need to be considered for accurate predictions of immersion cooling applications.</p>

Fluid-structure interactions occur in many engineering and industrial applications. Such interactions may result in undesirable forces acting on the structure that may cause fatigue and degradation of the structural components. The purpose of this research is to develop a solver that simulates the fluid-structure interaction, assess tools that can be used to control the resulting motions and analyze a system that can be used to convert the structure's motion to a useful form of energy. For this purpose, we develop a code which encompasses three-dimensional numerical simulations of a flow interacting with a freely-oscillating cylinder. The solver is based on the accelerated reference frame technique (ARF), in which the momentum equations are directly coupled with the cylinder motion by adding a reference frame acceleration term; the outer boundary conditions of the flow domain are updated using the response of the cylinder. We develop active linear and nonlinear velocity feedback controllers that suppress VIV by directly controlling the cylinder's motion. We assess their effectiveness and compare their performance and required power levels to suppress the motion of the cylinder. Particularly, we determine the most effective control law that requires minimum power to achieve a desired controlled amplitude. Furthermore, we investigate, in detail, the feasibility of using a nonlinear energy sink to control the vortex-induced vibrations of a freely oscillating circular cylinder. It has been postulated that such a system, which consists of a nonlinear spring, can be used to control the motion over a wide range of frequencies. However, introducing an essential nonlinearity of the cubic order to a coupled system could lead to multiple stable solutions depending on the initial conditions, system's characteristics and parameters. Our investigation aims at determining the effects of the sink parameters on the response of the coupled system. We also investigate the extent of drag reduction that can be attained through rotational oscillations of the circular cylinder. An optimization is performed by combining the CFD solver with a global deterministic optimization algorithm. The use of this optimization tool allows for a rapid determination of the rotational amplitude and frequency domains that yield minimum drag. We also perform three-dimensional numerical simulations of an inline-vibrating cylinder over a range of amplitudes and frequencies with the objective of suppressing the lift force. We compare the amplitude-frequency response curves, levels of lift suppression, and synchronization maps for two- and three-dimensional flows. Finally, we evaluate the possibility of converting vortex-induced vibrations into a usable form of electric power. Different transduction mechanisms can be employed for converting these vibrations to electric power, including electrostatic, electromagnetic, and piezoelectric transduction. We consider the piezoelectric option because it can be used to harvest energy over a wide range of frequencies and can be easily implemented. We particularly investigate the conversion of vortex-induced vibrations to electric power under different operating conditions including the Reynolds number and load resistance. / Ph. D.

My thesis is a presentation of Jika Laufen for the international exhibition Expo 2015 in Milan. The work consists of designing and installing sinks into the exposure so that they are in a uniform manner. I designed the concept of the well for several reasons: the bathroom is an intimate space where it should be emphasized emotion , atmosphere and feelings. It is a space where a person should relax. The second aspect is that the ceramic has an organic origin, came from the ground and through the fire becomes very durable and solid. A no less important is the third aspect, exist on the context. Expo is an international exhibition and therefore the presentation of this forest exposure does not represent a Czech company, but also a Czech environment, where you will find beautiful nature and sources of known rivers. My concept is based on emotion and contrast materials. Delicate white ceramics have planted in a sharp stone and dark green leafy moss, creating a contrast full voltage . The exhibition of this type should not be missed even modern technology. That is my proposal represented feeler drain, which is around the perimeter of the sink hidden under the edge so as not to disturb the perception of the whole.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19051号 / 農博第2129号 / 新制||農||1033(附属図書館) / 学位論文||H27||N4933(農学部図書室) / 32002 / 京都大学大学院農学研究科農学専攻 / (主査)教授 白岩 立彦, 教授 奥本 裕, 准教授 中﨑 鉄也 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Markanvändningssektorn (LULUCF) står för 7–11 % av de globala utsläppen av växthusgaser, däribland koldioxid (CO2), metan (CH4) och dikväveoxid (N2O). Genom förändringar av markanvändningen kan kolinlagringen i mark och vegetation ökas och sektorn kan istället vara med och bromsa klimatförändringarna. Åtgärder för att minska nettoutsläppen av växthusgaser måste vidtas på alla nivåer i samhället, däribland kommuner. Ökad kunskap om kolförråd och kolsänkor samt kartläggning av dessa är ett första steg för åtgärder på kommunnivå. Förutom att bromsa klimatförändringarna måste samhället hitta sätt att anpassa sig till ett förändrat klimat. En strategi för det är att bygga resiliens, vilket i levande system syftar på systemens förmåga att absorbera och hantera förändringar samt anpassa sig till dem och utvecklas av dem. En faktor som stärker resiliensen i ett samhälle är hög biologisk mångfald i ekosystemen. Biologisk mångfald påverkas liksom kolinlagring av markanvändningen och sättet som marken generellt brukas på idag leder till förlust av biologisk mångfald. Syftet med denna rapport är att beräkna kolförråd och kolbalans i mark och vegetation inom Tierps kommun. Vidare är syftet att analysera hur markanvändningen påverkar kolinlagring och biologisk mångfald samt hur dessa kan gynnas genom att anpassa markanvändningen. Studien undersöker även den potentiella betydelsen av biologisk mångfald och arbetet med kolinlagring för att skapa resiliens och bromsa klimatförändringarna. Forskningsstrategin var en fallstudie och för att besvara syftet användes en kombination av kvalitativ och kvantitativ metod. Den kvalitativa delen bestod av en litteraturstudie och den kvantitativa delen utgjordes av beräkningar av kolförråd och kolbalans i Tierps kommun. Vid beräkning delades marktäcket in i sex olika markklasser på organogen och minerogen mark. Kolförrådet delades upp i tre kolpooler; markkol, dött organiskt material och levande biomassa. Resultatet visar att kommunens totala kolförråd uppgår till cirka 25 036 639 ton kol. Av de tre olika kolpoolerna är det markkol som lagrar störst mängd kol inom samtliga markklasser. Nettoupptaget i kommunen är -655 466 ton koldioxidekvivalenter (CO2e) per år med nuvarande markanvändning, där kolpoolen levande biomassa står för majoriteten av koldioxidupptaget. För att öka kolinlagringen i mark och vegetation och gynna den biologiska mångfalden presenteras förslag på förändrad markanvändning. Dessa grupperas i tre olika områden; ökning av mängden levande biomassa, återvätning samt stärka urbana grönytor. Varje område inkluderar ett flertal åtgärdsförslag. Slutsatsen är att mark och vegetation inom Tierps kommuns totalt sett är en kolsänka och med en förändrad markanvändning kan både kolinlagring och biologisk mångfald gynnas, vilket kan bidra till att klimatförändringarna bromsas och resiliensen stärks. / The land use sector (LULUCF) accounts for 7–11 % of global greenhouse gas emissions, including carbon dioxide (CO2), methane (CH4) and dinitrogen oxide (N2O). Through changes in land use, the carbon storage in soil and vegetation can be increased and the sector can instead play a part in mitigate climate change. Measures to reduce net emissions of greenhouse gases must be taken at all levels of society, including municipalities. Increased knowledge about carbon stores and carbon sinks and their mapping is a first step for measures at the municipal level. In addition to mitigate climate change, society must find ways to adapt to a changing climate. One strategy for that is to build resilience, which in living systems refers to the systems' ability to absorb and manage change as well as adapt to and evolve from it. A factor that strengthens the resilience of a society is high biodiversity in the ecosystems. Biodiversity, like carbon storage, is affected by land use and the way which land is generally used today contribute to the loss of biodiversity. The purpose of this report is to calculate carbon stocks and carbon balance in soil and vegetation within the municipality of Tierp. Furthermore, the aim is to analyze how land use affects carbon storage and biodiversity and how these can be benefited by adapting land use. The study also examines the potential significance of biodiversity and the work with carbon storage to create resilience and mitigate climate change. The research strategy employed a case study approach and a combination of qualitative and quantitative methods was used to address the research objectives. The qualitative component consisted of a literature review, while the quantitative component involved calculations of carbon stocks and balance in the municipality of Tierp. The land cover was divided into six different land classes for both organic and mineral soil types. The carbon stock was divided into three carbon pools; soil carbon, dead organic matter and living biomass. The result shows that the total carbon stock in the municipality amounts to approximately 25 036 639 tons of carbon. Among the three carbon pools, soil carbon stores the largest amount of carbon across all land classes. With the current land use, the net uptake in the municipality is -655 466 tons of carbon dioxide equivalents (CO2e) per year, with the living biomass pool contributing the majority of carbon dioxide uptake. In order to increase carbon storage in soil and vegetation and benefit biodiversity, suggestions for changes in land use are presented. These suggestions are grouped into three areas; increasing the amount of living biomass, rewetting and strengthening urban green areas. Each area includes several proposed actions. The conclusion is that, overall, the soil and vegetation within the municipality of Tierp serve as a carbon sink, and with altered land use, both carbon storage and biodiversity can be enhanced, contributing to mitigating climate change and strengthening resilience.