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Etudes théorique et expérimentale du suivi de particules uniques en conditions extrêmes : imagerie aux photons uniques / Theorical and experimental study of single particle tracking in extreme conditions : single photon imagingCajgfinger, Thomas 19 October 2012 (has links)
Ce manuscrit présente mon travail de thèse portant sur le détecteur de photons niques electron-bpmbarded CMOS (ebCMOS) à haute cadence de lecture (500 images/seconde). La première partie compare trois détecteurs ultra-sensibles et leurs méthodes d'amélioration de la sensibilité au photon : le CMOS bas bruit sCMOS), l'électron-multiplying CCD (emCCD) à multiplication du signal apr pixel et l'ebCMOS à amplification par application d'un champ électrique. La méthode de mesure de l'impact intra-pixel des photons sur le détecteur ebCMOS est présentée. La seconde partie compare la précision de localisation de ces trois détecteurs dans des conditions extrêmes de très bas flux de phtons (<10 photons/image). La limite théoriques est d'abord calculée à l'aide de la limite inférieure de Cramér-Rao pour ces jeux de paramètres significatifs. Une comparaison expérimentale des trois détecteurs est ensuite décrite. Le montage permet la création d'un ou plusieurs points d'accès contrôlés en position, nombre de photons et bruit de fond. Les résultats obtenus permettent une comparaison de l'efficacité, de la pureté et de la précision de localisation des sources. La dernière partie décrit deux expériences réalisées avec la caméra ebCMOS. La première consiste au suivi des nano-cristaux libres (D>10 µm2/s) au centre Nanoptec avec l''équipe de Christophe Dujardin. La seconde s'intéresse à la nage de bactéries en surface à l'Institu Joliot curie avec l'équipe de Laurence Lemelle. L'algorithme de suivi de sources ponctuelles au photon unique avec l'implémentation d'un filtre de Kalman est aussi décrit. / This manuscript presents my thesis on the high frame rate (500 frames/second) single-photon detector electron-bombraded CMOS (ebCMOS). The first section compares three ultra-sensitive detectors and their methods for improving photon sensitivity : the CMOS low noise (sCMOS), the electron-multiplying CCD (emCCD) with signal multiplication by pixel and the ebCMOS with amplification by applied electric field. The method developped to detected single photon impacts with intra-pixel resolution on the ebCMOS sensor is presented. The second section compares the localization accuracy of these detectors in extreme conditions of very low photon flux (<10 photons/ frame). First the theoretical limit is calculated using the Cramér-Rao lower bound for significant parameter sets. An experimental comparaison of the detectors is then described. The setup provides of one or more point sources controlled in position, signal and background noise. The results allow a comparison of the experimental effectiveness, purity and localization accuracy. The last section describes two experiments with the ebCMOS camera. The first aims to track hundreds of quantum dots simultaneously at the Nanoptec center with the team of Christophe Dujardin. The second focuses on the swimming of bacteria at the surface at the Jolio Curie Institute with the team of Laurence Lemelle. The point sources tracking algorithm using single photons and the Kalman filter implementation developed for these experiments is alson described.
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Influence of Photosynthetic Photon Flux Density on UV-BInduced Photoinhibition in Soybean Leaves: Comparison of Preconditioning and Concomitant Light TreatmentsWarner, Charles W. 01 May 1982 (has links)
Previous studies indicate that the degree of UV-Binduced photosynthetic inhibition may be highly dependent upon the photosynthetic photon flux density (PPFD, total quantum flux in the waveband 400-700 nm) incident on a plant. This study illustrates that Essex soybean leaves (Glycine max) preconditioned under high PPFD suffered less UV-B-induced photoinhibition than when preconditioned under low PPFD. However, sensitivity to UV-B increased when soybean leaves received high-PPFD as a concomitant treatment.
The relative msgnitude of UV-B-induced damage was similar for both light-limited and light-saturated photosynthesis. This probably indicates that UV-B is inhibiting fundamentally different photosynthetic processes.
Soybean leaves preconditioned under high PPFD had greater specific-leaf-weight, chlorophyll a/b ratio, and crude flavonoid content. The total chlorophyll concentration of soybean leaves preconditioned under high PPFD increased slightly over a UV-B irradiation period of five hours. Total chlorophyll concentration of leaves preconditioned under low PPFD decreased slightly in response to the same irradiation period.
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Simulation of the irradiation behaviour of the PBMR fuel in the SAFARI-1 reactor / B.M. MakgopaMakgopa, Bessie Mmakgoto January 2009 (has links)
Irradiation experiments for the pebble bed modular reactor PBMR fuel (coated fuel particles and pebble
fuel) are planned at the South African First Atomic Reactor Installation (SAFARI-1). The experiments
are conducted to investigate the behavior of the fuel under normal operating and accelerated/accident
simulating conditions because the safe operation of the reactor relies on the integrity of the fuel for
retention of radioactivity.
For fuel irradiation experiments, the accurate knowledge and analysis of the neutron spectrum of the
irradiation facility is required. In addition to knowledge of the neutron spectrum in the irradiation facility,
power distributions and knowledge of nuclear heating values has to be acquired. The SAFARI-1 reactor
boosts operating fluid temperatures of about 300 K. On the contrary, the PBMR can reach temperatures in
up to about 1370 K under normal operating conditions. This calls for design of high temperature
irradiation rigs for irradiation of the PBMR fuel in the SAFARI-1 reactor. The design of this instrument
(rig) should be such that to create an isolated high temperature environment in the SAFARI-1 reactor, to
achieve the requirements of the PBMR fuel irradiation program. The design of the irradiation rig is
planned such that the rig should fit in the existing irradiation channels of the SAFARI-1 reactor, a time
and cost saving from the licensing perspective.
This study aims to establish the know-how of coated particle and pebble modeling in using the Monte
Carlo N-Particle code (MCNP5). The study also aims to establish the know-how of rig design. In this
study, the Necsa in-house code Overall System for the Calculation of Reactors (OSCAR-3), a software
known as OScar 3-Mcnp INTerface (OSMINT) linking OSCAR-3 and MCNP5, also developed at Necsa,
as well as MCNP5 code developed and maintained by the Los Alamos team, are used to calculate
neutronic and power distribution parameters that are important for fuel irradiations and for rig design.
This study presents results and data that can be used to make improvements in the design of the rig or to
confirm if the required operational conditions can be met with the current preliminary rig design. Result
of the neutronic analysis are presented for the SAFARI-1 core, core irradiation channel B6 (where the
PBMR fuel irradiation rig is loaded for the purpose of this study), the rig structure and the pebble fuel are
presented. Furthermore results of the power distribution and nuclear heating values in the reactor core, the
irradiation channel B6, the rig structures and the pebble fuel is also presented.
The loading of the PBMR fuel irradiation rig in core position B6 reduces the core reactivity due to the
fact that the loading of the rig displaces the water moderator in channel B6 introducing vast amounts of
helium. This impacts on the keff value because there will be less neutron thermalization and reproduction
due to the decreased population of thermal neutrons. The rig is found to introduce a negative reactivity
insertion of 46 pcm. The loading of this rig in the core leads to no significant perturbations on the core
power distribution. The core hottest channel is still localized in core channel C6 both with RIG IN and RIG OUT cases. A power tilt is observed, with the south side of the core experiencing reduced assembly
averaged fission power, with correspondingly small compensations from the assemblies on the north side
of the core.
The perturbations on the core assembly averaged fluxes are more pronounced in the eight assemblies
surrounding B6. Core position B6 suffers an 18% neutron flux depression with the loading of the rig. The
fluxes in core positions A5, A6, A7, B5, B7 and C7 are increased when the rig is loading. The largest
increases are noted as 12% in A7, 9% in A6 and 6% in A5 and B7. All the eight core positions
surrounding B6 experience reduced photon fluxes with the loading of the rig. Core position B6 shows a
flux depression of up to 20%, with 10% reduction in core position A6. The remainder seven positions
surrounding B6 shows flux depressions of no more than 5%.
Further on, due to decreased moderation effects, the axial neutron flux in core position B6 is reduced by
20% when the rig is loaded. The energy dependent neutron flux in B6 decreases by 50% in the thermal
energy range with corresponding increases of up to 50% in the resonance and fast energy regions. The
axial and the energy dependent photon flux in core position B6 decreases by up to 20% when the rig is
loaded.
The magnitude of the neutron and photon fluxes is found to have a direct proportion on the neutron and
photon heating values. While the amount of neutron heating in core position B6 increases by one order of
magnitude, when the rig is loaded, the photon heating values increases by up to 60% in the region
spanning ±10cm about the core centerline. The amount of photon heating in the rig structural materials
dominates neutron heating, except in the helium regions of the rig, where neutron heating dominates
photon heating. In the fuel region of the pebble, fission heating (3803W) largely dominates photon heating (119W). / Thesis (M.Sc. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2009
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Simulation of the irradiation behaviour of the PBMR fuel in the SAFARI-1 reactor / B.M. MakgopaMakgopa, Bessie Mmakgoto January 2009 (has links)
Irradiation experiments for the pebble bed modular reactor PBMR fuel (coated fuel particles and pebble
fuel) are planned at the South African First Atomic Reactor Installation (SAFARI-1). The experiments
are conducted to investigate the behavior of the fuel under normal operating and accelerated/accident
simulating conditions because the safe operation of the reactor relies on the integrity of the fuel for
retention of radioactivity.
For fuel irradiation experiments, the accurate knowledge and analysis of the neutron spectrum of the
irradiation facility is required. In addition to knowledge of the neutron spectrum in the irradiation facility,
power distributions and knowledge of nuclear heating values has to be acquired. The SAFARI-1 reactor
boosts operating fluid temperatures of about 300 K. On the contrary, the PBMR can reach temperatures in
up to about 1370 K under normal operating conditions. This calls for design of high temperature
irradiation rigs for irradiation of the PBMR fuel in the SAFARI-1 reactor. The design of this instrument
(rig) should be such that to create an isolated high temperature environment in the SAFARI-1 reactor, to
achieve the requirements of the PBMR fuel irradiation program. The design of the irradiation rig is
planned such that the rig should fit in the existing irradiation channels of the SAFARI-1 reactor, a time
and cost saving from the licensing perspective.
This study aims to establish the know-how of coated particle and pebble modeling in using the Monte
Carlo N-Particle code (MCNP5). The study also aims to establish the know-how of rig design. In this
study, the Necsa in-house code Overall System for the Calculation of Reactors (OSCAR-3), a software
known as OScar 3-Mcnp INTerface (OSMINT) linking OSCAR-3 and MCNP5, also developed at Necsa,
as well as MCNP5 code developed and maintained by the Los Alamos team, are used to calculate
neutronic and power distribution parameters that are important for fuel irradiations and for rig design.
This study presents results and data that can be used to make improvements in the design of the rig or to
confirm if the required operational conditions can be met with the current preliminary rig design. Result
of the neutronic analysis are presented for the SAFARI-1 core, core irradiation channel B6 (where the
PBMR fuel irradiation rig is loaded for the purpose of this study), the rig structure and the pebble fuel are
presented. Furthermore results of the power distribution and nuclear heating values in the reactor core, the
irradiation channel B6, the rig structures and the pebble fuel is also presented.
The loading of the PBMR fuel irradiation rig in core position B6 reduces the core reactivity due to the
fact that the loading of the rig displaces the water moderator in channel B6 introducing vast amounts of
helium. This impacts on the keff value because there will be less neutron thermalization and reproduction
due to the decreased population of thermal neutrons. The rig is found to introduce a negative reactivity
insertion of 46 pcm. The loading of this rig in the core leads to no significant perturbations on the core
power distribution. The core hottest channel is still localized in core channel C6 both with RIG IN and RIG OUT cases. A power tilt is observed, with the south side of the core experiencing reduced assembly
averaged fission power, with correspondingly small compensations from the assemblies on the north side
of the core.
The perturbations on the core assembly averaged fluxes are more pronounced in the eight assemblies
surrounding B6. Core position B6 suffers an 18% neutron flux depression with the loading of the rig. The
fluxes in core positions A5, A6, A7, B5, B7 and C7 are increased when the rig is loading. The largest
increases are noted as 12% in A7, 9% in A6 and 6% in A5 and B7. All the eight core positions
surrounding B6 experience reduced photon fluxes with the loading of the rig. Core position B6 shows a
flux depression of up to 20%, with 10% reduction in core position A6. The remainder seven positions
surrounding B6 shows flux depressions of no more than 5%.
Further on, due to decreased moderation effects, the axial neutron flux in core position B6 is reduced by
20% when the rig is loaded. The energy dependent neutron flux in B6 decreases by 50% in the thermal
energy range with corresponding increases of up to 50% in the resonance and fast energy regions. The
axial and the energy dependent photon flux in core position B6 decreases by up to 20% when the rig is
loaded.
The magnitude of the neutron and photon fluxes is found to have a direct proportion on the neutron and
photon heating values. While the amount of neutron heating in core position B6 increases by one order of
magnitude, when the rig is loaded, the photon heating values increases by up to 60% in the region
spanning ±10cm about the core centerline. The amount of photon heating in the rig structural materials
dominates neutron heating, except in the helium regions of the rig, where neutron heating dominates
photon heating. In the fuel region of the pebble, fission heating (3803W) largely dominates photon heating (119W). / Thesis (M.Sc. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2009
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Sistema eletrônico baseado em diodos emissores de luz (LEDs) para aplicação em estudos de fisiologia vegetalAlmeida, Camila do Carmo 29 August 2014 (has links)
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Previous issue date: 2014-08-29 / Este trabalho teve por objetivos projetar um sistema eletrônico de controle destinado a fornecer uma alternativa simplificada e eficiente para estudos de fisiologia vegetal envolvendo luz artificial, bem como para sua utilização em determinados processos de cultivo de plantas em estufas. O trabalho apresenta uma revisão sobre a interação entre a iluminação artificial e o cultivo de plantas, tanto para o propósito de uma cultura comercial quanto para possibilitar a interpretação do comportamento de plantas em estudos botânicos. Este sistema eletrônico possibilita a determinação das quantidades radiométricas de interesse quando a iluminação artificial é usada como suplemento ou como única fonte de iluminação em cultivos. Com base em estudos anteriores, é proposto a produção de um sistema autônomo constituído por um aparelho de iluminação composto por LEDs brancos e/ou coloridos. Além disso, foram realizados alguns experimentos radiométricos preliminares utilizando luminárias comerciais de LEDs, visando sua utilização em associação com o sistema de controle proposto. Os parâmetros medidos mais relevantes foram o fluxo de fótons fotossinteticamente ativos, fluxo luminoso e a temperatura de cor correlata. Espera-se que o protótipo desenvolvido apresente características que agreguem flexibilidade e comportamento radiométrico relevante para cultivos controlados. / This work aims to develop an electronic control system with the purpose to drive a simplified and efficient alternative for vegetal physiology studies involving artificial light as well as for its utilization in certain plants crop at greenhouses. Additionally, this work presents a brief review regarding the interaction between artificial lighting and plants, with purposes of commercial crops and the possibility of interpretation of plants behavior in botanic studies. This electronic system enables the determination of the radiometric quantities of interest when the lighting is used as a supplement or as the only lighting source in crops. Using the latest studies, it is proposed an autonomous system consisting basically of white and/or colored LEDs. Besides, it were performed radiometric experiences using commercial luminaires with LEDs aiming the use of them in the proposed control system. The more relevant measured parameters were the photosynthetic photon flux, luminous flux and correlated colour temperature. The proposed system shows flexibility and relevant radiometric behavior, which are particularly useful in Plant Physiology.
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Respostas fisiológicas e controle de Meloidogyne incognita em plantas de tomateiro tratadas com soluções ultradiluídas de Thuya occidentalis / Physiological responses and control of Meloidogyne incognita em tomato plants treated with high-diluted solution of Thuya occidentalisMioranza, Thaísa Muriel 25 February 2015 (has links)
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Previous issue date: 2015-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this work was to study the influence of homeopathic or high diluted solution of Thuya occidentalis in the control of root-knot nematode Meloidogyne incognita in tomato plants and physiological responses promoted in the plant. The experiment consisted of in vitro and in vivo assay. The treatments were different dynamization of T. occidentalis 6, 12, 24, 50, 100, 200 and 400CH (centesimal hahnemaniana dilution) and the water (control). In the in vitro experiment nematodes were treated with 0.1% homeopathic solution of the treatments for 24 hours for the motility test and 15 days for hatching test. For the in vivo test, the experiment was carried out in two years, the first year in completely randomized design and the second year in a randomized block design, both with eight treatments and with four replications. At the moment that the tomato seedlings were transplanted, they were submerged in a 0.1% solution of treatments. Subsequently were inoculated 4188 eggs and 661 second-stage juveniles (J2) in the first experiment and 4350 eggs and 700 J2 in the second experiment. Were performed weekly sprays of 0.1% solution of the treatments in the shoots of plants. The plants were cultivated until the nematodes complete a development cycle. We evaluated the number of galls, egg masses, number of eggs and J2 in the roots, number of eggs and J2 in the soil, plant height, shoot fresh and dry weight, root volume, number of clusters, number of fruits per bunch, fresh and dry fruit weight and relative chlorophyll content. In the 2014 experiment were chosen the dynamizations 6, 24 and 50CH, and the control with nematode and treated with water and plants without nematodes and without treatment, with four repetitions each for the measurement of photosynthesis rates (A), stomatal conductance (gs), transpiration (E), internal CO2 concentration on leaf (Ci) and leaf temperature (Tleaf) varying the photosynthetic photon flux density (PPFD). It was also calculated the efficiency of water use (USA) (A/E), intrinsic water use efficiency (EUIA) (A/gs) and the instantaneous efficiency of carboxylation (A/C). The treatments did not show nematostatic and nematicide effect even did not influence in hatches eggs for in vitro assay. To the in vivo assay, in 2013, T. occidentalis 100CH caused a reduction in the population of J2 in the roots, as well as 200CH promoted an increase in the volume root and fruit fresh weight of the first bunch. In 2014, 100CH caused a decrease in the number of egg masses and J2 in the soil, and influenced the development of the root, while 50CH increased the fresh weight of shoots of tomato plants. The specific measures of gas exchange did not differ between treatments. Plants infected with M. incognita and without treatment caused an increase in the net photosynthesis and the carboxylation capacity for response curve to light. Already T. occidentalis 24CH inhibited the effect of increased CO2 fixation in tomato plants inoculated with M. incognita, providing similar behavior to healthy plants in different densities of photons. Plants of homeopathic treatments showed higher leaf temperature. T. occidentalis showed control capability of root-knot nematode and influenced in tomato growth and physiology / O objetivo desse trabalho foi estudar a influência de soluções ultradiluídas de Thuya occidentalis no controle do nematoide de galhas Meloidogyne incognita em plantas de tomateiro e as respostas fisiológicas promovidas na planta. O experimento foi constituído de ensaios in vitro e in vivo. Os tratamentos utilizados foram diferentes dinamizações de T. occidentalis 6, 12, 24, 50, 100, 200 e 400CH (centesimal hahnemanniana) e a testemunha água (controle). No experimento in vitro os nematoides ficaram em contato direto com a solução de 0,1% dos tratamentos, por 24 horas para o teste de motilidade e 15 dias para o teste de eclosão. Para o teste in vivo, o experimento foi realizado em dois anos, sendo o primeiro ano em delineamento inteiramente casualizado e o segundo ano em delineamento de blocos ao acaso, ambos com oito tratamentos e quatro repetições. No momento em que as mudas de tomateiro foram transplantadas, estas foram submersas em uma solução de 0,1% dos tratamentos. Posteriormente foram inoculados 4188 ovos e 661 juvenis de segundo estágio (J2) no primeiro experimento e 4350 ovos e 700 J2 no segundo experimento. Foram realizados pulverizações semanais da solução de 0,1% dos tratamentos na parte aérea das plantas. As plantas foram conduzidas até que os nematoides completassem um ciclo de desenvolvimento. Foram avaliados o número de galhas, massas de ovos, número de ovos e J2 nas raízes, número de ovos e J2 no solo, altura de plantas, massa fresca e seca da parte aérea, volume de raiz, número de cachos, número de frutos por cacho, massa fresca e seca dos frutos e teor relativo de clorofila. No experimento de 2014, foram escolhidas as dinamizações de 6, 24 e 50CH, além da testemunha com nematoide e tratada com água e testemunha sem nematoide e sem tratamento, com quatro repetições cada, para a mensuração da taxa de assimilação líquida de CO2 (A), transpiração foliar (E), condutância estomática (gs), concentração interna de CO2 (Ci) e temperatura foliar (°C), variando-se a densidade de fluxo de fótons fotossinteticamente ativos (DFFFA). Também foi calculada a eficiência no uso da água (EUA) (relação A/E), eficiência intrínseca no uso da água (EUIA) (relação A/gs) e a eficiência instantânea da carboxilação (A/Ci) (relação A/Ci). Os tratamentos não mostraram efeito nematostático e nematicida assim como não influenciaram na eclosão de ovos para o ensaio in vitro. Já para o in vivo, em 2013, T. occidentalis 100CH causou redução na população de J2 nas raízes, assim como 200CH promoveu aumento no volume de raiz e massa fresca de frutos do primeiro cacho. Em 2014, 100CH promoveu diminuição no número de massas de ovos e J2 no solo, e influenciou no desenvolvimento da raiz, enquanto 50CH incrementou a massa fresca da parte aérea de tomateiro. As medidas pontuais de trocas gasosas não apresentaram diferença entre os tratamentos. Plantas infectadas com M. incognita e sem tratamento promoveram aumento na fotossíntese líquida e capacidade de carboxilação pela curva de resposta à luz. Já T. occidentalis 24CH inibiu o efeito de maior fixação de CO2 em tomateiros inoculados por M. incognita, proporcionando comportamento semelhante às plantas sadias em diferentes densidades de fótons. Plantas submetidas aos tratamentos homeopáticos apresentaram maior temperatura foliar. T. occidentalis apresentou capacidade de controle de nematoide de galhas e influenciou no crescimento e fisiologia do tomateiro
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Optimální využití energie a vody v aquaponické farmě / Resource optimisation in the indoor aquaponic farmOndruška, Vojtěch January 2020 (has links)
Energetická náročnost a ekonomická životaschopnost jsou často skloňované pojmy spojené s aquaponickým způsobem produkce potravin. Tato práce si klade za cíl nalézt opatření, která by zvýšila ziskovost podnikání v oblasti aquaponie a zároveň by snížila energetickou náročnost procesu a spotřebu dalších zdrojů. Součástí práce je následné ověření vybraných opatření na zkušební aquaponické farmě. K vyřešení otázky úspory energie a vody byly použity optimalizační metody vycházející z procesního inženýrství. Pro účely automatického monitoringu růstu rostlin, jakožto hlavního zdroje příjmů v aquaponii, byla využita technologie počítačového vidění. Za využití optimalizační metody zvané P-graph, integrace procesů a hledání procesních alternativ bylo nalezeno nejlepší možné uspořádání procesní sítě, které vykazovalo více než devítinásobný čistý roční příjem ve srovnání se současným uspořádáním procesních zařízení v aquaponické farmě. Dalších úspor energie a vody bylo dosaženo instalací reflexních fólií na okraje pěstebních boxů a dalším využitím odpadní vody z aquaponické části farmy v hydroponické sekci určené k pěstování sazenic. Tato opatření mohou napomoci aquaponickým farmám zvýšit konkurenceschopnost a snížit jejich dopad na životní prostředí.
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