Tesi sul tema "Irradiation method"
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1
Cheng, Yulin, Jiacheng Wu, Jinwei Zhang e Wuyong Chen. "A Novel Collagen Extraction Method Based on Microwave Irradiation - 79". Verein für Gerberei-Chemie und -Technik e. V, 2019. https://slub.qucosa.de/id/qucosa%3A34275.
Abstract (sommario):
Content:
Microwave was used as a thermal source to extract collagen acid from the cattle hide in the present work. The effects of microwave on collagen extraction yields were studied under different microwave
temperatures, time and hide-liquid ratio. The optimal extraction process was obtained by an orthogonal experiment, and the composition, structure and properties of the extracted collagen were characterized by amino acid analysis, SDS-PAGE, FTIR, UV-Vis, CD, FL, and VP-DSC. The results showed that the extraction rate of collagen was positively correlated with temperature, time and hide-liquid ratio. Under the condition of 35 °C, 6 h and 1:30 of solid-liquid ratio, the extraction proportion of collagen extracted under microwave was the highest, reaching to 13.40 %. The extracted collagen was identified as type I collagen by Amino acid analysis, and the graphic pattern of SDS-PAGE, FTIR and UV-Vis showed that the extracted collagen was similar to the standard type I collagen. Also, the results suggest that the triple helical structure exists still in the extracted collagen. The transition from triple helix to random coil of the extracted collagen was 41 ℃. These results provide a scientific basis for microwave technology for the extraction of collagen.
Take-Away:
The results showed that the extraction rate of collagen was positively correlated with temperature, time and hide-liquid ratio. Under the condition of 35 °C, 6 h and 1:30 of solid-liquid ratio, the extraction
proportion of collagen extracted under microwave was the highest, reaching to 13.40 %. The extracted collagen was identified as type I collagen by Amino acid analysis, and the graphic pattern of SDS-PAGE,
FTIR and UV-Vis showed that the extracted collagen was similar to the standard type I collagen. Also, the results suggest that the triple helical structure exists still in the extracted collagen. The transition from triple helix to random coil of the extracted collagen was 41 ℃. These results provide a scientific basis for microwave technology for the extraction of collagen.
2
Robertson, Stephanie. "Microstructural manipulation by laser irradiation of prepared samples : The ’Snapshot Method’". Licentiate thesis, Luleå tekniska universitet, Produkt- och produktionsutveckling, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76150.
Abstract (sommario):
Various metallurgical microstructures and their formation are studied in this thesis by using a laser beam to melt a variety of materials with different chemical compositions over a range of thermal cycles. The laser beam was used conventionally in a narrow gap multi-layer weld, used for welding large depths with filler wire additions, as well as a non-traditional simulated welding approach labelled here as the Snapshot method. In laser beam welding, materials go through rapid heating and cooling cycles that are difficult to mimic by other techniques. In welding, any microstructural development depends on complex combinations of chemistry and thermal cycles but is also influenced by melt flow behavior. In turn, microstructural morphologies influence the mechanical behavior which can suffer due to inappropriate microstructural constituents. The Snapshot method, through control of thermal cycling and material composition, can achieve the same rates while guiding microstructural development to form tailored properties. The tunable laser beam properties can be exploited to develop an experimental welding simulation (Snapshot method), which enables the complex interlinked chemical and thermal events which take place during welding to be studied in a controlled manner. Exploring the microstructural relationships to their thermal history provides a greater knowledge into tailoring microstructural compositions to obtain various required mechanical properties for laser welding, additive manufacturing and also non-laser welding techniques. The feasibility of the Snapshot method is investigated in the three appended journal publications. High speed imaging and thermal recording have proved to be essential tools in this work, with analysis from optical microscopy and EDX/EDS to provide additional support. The Snapshot method is introduced as a concept in Papers I and II, demonstrating successfully guided thermal histories after obtaining molten material. Application of a second and third heating cycle, reheating the structure without melting, yielding altered microstructures. Reaching the austenitisation temperature range allowed for the simulation of complex multi-layer welding thermal histories. Geometrically non-uniform material additions are utilized in Paper III, which investigated the formation of microstructures through the chemical composition route. New chemical compositions were obtained by different degrees of dilution of the weld filler wire by the base material.
3
Parmar, Nishaal Jitendra. "Food irradiation as a method of limiting crop loss in developing nations". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/44830.
Abstract (sommario):
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2007.Includes bibliographical references (leaf 31-34).
Introduction: Introduction: The world today contains an estimated 6.7 billion humans, and our population is growing at an unprecedented rate, consuming an ever-increasing amount of global resources. According to United Nations projections, the majority of this growth will occur in the third-world nations of Africa, and, to a lesser extent, Asia, among those peoples least able to afford the increasing burden on their resources. Clearly, what is needed in these African nations in the near future are more efficient, low-cost methods of using those resources they already have. Foremost among the problems faced by African developing nations is a lack of a reliable, sufficient, and nutritious food supply. Much of the African population survives on malnourished diets irregularly supplied by subsistence agriculture. In addition, crop loss due to both pests and post-harvest spoilage is much higher than in first world nations, with cold-storage technologies and modem pesticides. Equally important are the lives lost each year to food-borne disease. In the United States alone, food-borne infections cause an estimated 76 million cases of illness and 323,000 hospitalizations annually, for an estimated annual treatment cost of $6.7 billion and a death toll of thousands. In developing nations, of course, these casualty figures are much higher. It is precisely this crop loss and food-borne disease which this thesis proposes to address, by both proposing and evaluating a method, namely, food irradiation, to diminish crop loss in African villages and small-towns. As stated by Fritz Kaferstein in the Journal of Public Health Policy, "In developing countries with warm climates, with non-grain staples, vegetables and fruits, the pos-tharvest loss is believed to exceed 50%. With commodities such as dried fish, insect infestation is reported to result in a loss of 25% of the product with an additional 10% lost due to spoilage. While not all of these losses can be prevented by food irradiation, the technology does offer unique potential to destroy insect infestation and reduce spoilage."
by Nishaal Jitendra Parmar.
S.B.
4
Jang, Si Young. "Advanced neutron irradiation system using Texas A&M University Nuclear Science Center Reactor". Texas A&M University, 2004. http://hdl.handle.net/1969.1/2788.
Abstract (sommario):
A heavily filtered fast neutron irradiation system (FNIS) was developed for a variety of applications, including the study of long-term health effects of fast neutrons by evaluating the biological mechanisms of damage in cultured cells and living animals such as rats or mice. This irradiation system includes an exposure cave made with a lead-bismuth alloy, a cave positioning system, a gamma and neutron monitoring system, a sample transfer system, and interchangeable filters. This system was installed in the irradiation cell of the Texas A&M University Nuclear Science Center Reactor (NSCR).
By increasing the thickness of the lead-bismuth alloy, the neutron spectra were shifted into lower energies by the scattering interactions of fast neutrons with the alloy. It is possible, therefore, by changing the alloy thickness, to produce distinctly different dose weighted neutron spectra inside the exposure cave of the FNIS. The calculated neutron spectra showed close agreement with the results of activation foil measurements, unfolded by SAND-II close to the cell window. However, there was a considerable less agreement for locations far away from the cell window. Even though the magnitude of values such as neutron flux and tissue kerma rates in air differed, the weighted average neutron energies showed close agreement between the MCNP and SAND-II since the normalized neutron spectra were in a good agreement each other.
A paired ion chamber system was constructed, one with a tissue equivalent plastic (A-150) and propane gas for total dose monitoring, and another with graphite and argon for photon dose monitoring. Using the pair of detectors, the neutron to gamma ratio can be inferred. With the 20 cm-thick FNIS, the absorbed dose rates of neutrons measured with the paired ion chamber method and calculated with the SAND-II results were 13.7 ?? 0.02 Gy/min and 15.5 Gy/min, respectively. The absorbed dose rate of photons and the gamma contribution to total dose were 6.7??10-1 ?? 1.3??10-1 Gy/min and 4.7%, respectively. However, the estimated gamma contribution to total dose varied between 3.6 % to 6.6 % as the assumed neutron sensitivity to the graphite detector was changed from 0.01 to 0.03.
5
Jackman, Mary Megan. "Microwave-Promoted Iminyl Radical Fragmentations: A Practical and Efficient Method of Functionalization". BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6946.
Abstract (sommario):
We report a novel fragmentation and functionalization method using a cyclic iminyl radical. Formation of this radical occurs by microwave heating under mild conditions and short reaction times. The reaction avoids the use of explosive or toxic radical initiators and propagating agents. This reaction is versatile, with the ability to install two functional groups that are ultimately derived from a ketone in the substrate precursor. A variety of radical traps capable of forming both carbon-carbon bonds and carbon-heteroatom bonds have been tested, and the products are obtained in good yields. We demonstrate the power of this reaction by functionalizing complex natural products.
6
Amit, Kumar. "Food irradiation and development of an alternative method for the detection of 2-alkylcyclobutanone". Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/544.
7
Kumar, Amit. "Food irradiation and development of an alternative method for the detection of 2-Alkylcylcyclobutanone". Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/592.
8
Farzana, Esmat. "Defects and Schottky Contacts in β-Ga2O3:Properties, Influence of Growth Method and Irradiation". The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555495732936101.
9
Amit, Kumar. "Food irradiation and development of an alternative method for the detection of 2-Alkylcylcyclobutanone". Kansas State University, 2008. http://hdl.handle.net/2097/592.
Abstract (sommario):
Master of ScienceFood Science Institute
J. Scott Smith
Food irradiation is one of the most important food processing methods utilized to reduce microbial load and extend shelf life. In 1995 the World Health Organization (WHO) declared irradiated foods to be safe from a nutritional and toxicological point of view. Various methods have been applied to detect irradiated foods. Detection of 2-alkylcyclobutanones has been found to be a useful method in identifying irradiated foods. The solvent extraction method utilizes a Soxhlet apparatus for lipid extraction followed by clean up with Florisil. However, this method is very time consuming. The other methods available to detect 2-alkylcyclobutanone include supercritical fluid extraction (SFE), and accelerated solvent extraction method using a Dionex ASE 200 instrument. The SFE is a fast method to detected 2-alkylcyclobutanone. All the above mentioned methods involve costly equipment. The aim of this study was to eliminate the requirement of costly extraction equipment for lipid extraction before clean up or direct isolation of 2-alkylcyclobutanone as in case of SFE instrument using Florisil cartridges. In this study, the manual solvent extraction method was applied to isolate alkylcylcobutanone followed by clean up with 2 g silica cartridge. The clean up extract was injected to gas chromatography-flame ionization detector (GC-FID) for detection of 2-dodecylcyclobutanone (2-DCB). Gas chromatography-mass spectrometry (GC-MS) was used to confirm that the compound detected was 2-dodecylcyclobutanone. The ions m/z 98 and 112 were selected for 2-DCB for monitoring in selected ion monitoring (SIM) mode of GC-MS. The results showed that this method was able to detect 2-DCB from irradiated ground beef. The manual method does not require costly equipment such as supercritical fluid extractor, Dionex, or Soxlet apparatus for extraction process.
10
Dev, Kumar Govindaraj. "Effect of Ozone and Ultraviolet Irradiation Treatments on Listeria monocytogenes Populations in Chill Brines". Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/35954.
Abstract (sommario):
The efficacy of ozone and ultraviolet light, used in combination, to inactivate Listeria monocytogenes in fresh (9% NaCl, 91.86% transmittance at 254 nm) and spent chill brines (20.5% NaCl, 0.01% transmittance at 254 nm) was determined. Preliminary studies were conducted to optimize parameters for the ozonation of â freshâ and â spentâ brines. These include diffuser design, comparison of kit to standard methods to measure residual ozone, studying the effect of ozone on uridine absorbance and determining presence of residual listericidal activity post ozonation.
An ozone diffuser was designed using 3/16 inch PVC tubing for the ozonation of brines. The sparger was designed to facilitate better diffusion and its efficiency was tested. The modified sparger diffused 1.44 ppm of ozone after 30 minutes of ozonation and the solution had an excess of 1 ppm in 10 minutes of ozonating fresh brine solution (200ml). Population levels of L. monocytogenes were determined at various time intervals post-ozonation (0, 10, 20, 60 min) to determine the presence of residual listericidal activity. The population post ozonation (0 minutes) was 5.31 Log CFU/ml and was 5.08 Log CFU/ml after a 60 minute interval. Therefore, residual antimicrobial effect was weak. Accuracy of the Vacu-vial Ozone analysis kit was evaluated by comparing the performance of the kit to the standard indigo colorimetric method for measuring residual ozone. The kit was inaccurate in determining residual ozone levels of spent brines and 1% peptone water. Uridine was evaluated as a UV actinometric tool for brine solutions that were ozonated before UV treatment. The absorbance of uridine (A262) decreased after ozonation from 0.1329 to 0.0512 for standard 10 minutes UV exposure duration. Absorbance of uridine was influenced by ozone indicating that the presence of ozone may hamper UV fluence determination accuracy in ozone-treated solutions.
Upon completion of diffuser design and ozone/UV analysis studies, the effect of ozone-UV combination on L. monocytogenes in fresh and spent brines was evaluated. Ozonation, when applied for 5 minutes, caused a 5.29 mean Log reduction while 5 minutes of UV exposure resulted in a 1.09 mean Log reduction of L. monocytogenes cells in fresh brines. Ten minutes of ozonation led to a 7.44 mean Log reduction and 10 minutes of UV radiation caused a 1.95 mean Log reduction of Listeria in fresh brine.
Spent brines required 60 minutes of ozonation for a 4.97 mean Log reduction in L. monocytogenes counts, while 45 minutes resulted in a 4.04 mean Log reduction. Ten minutes of UV exposure of the spent brines resulted in 0.30 mean Log reduction in Listeria cells. A combination of 60 minutes ozonation and 10 minute UV exposure resulted in an excess of 5 log reduction in cell counts. Ozonation did not cause a sufficient increase in the transmittance of the spent brine to aid UV penetration but resulted in apparent color change as indicated by change in L*a*b* values. Ozonation for sufficient time had considerable listericidal activity in fresh brines and spent brines and when combined with UV treatment, is effective reducing L. monocytogenes to undetectable levels in fresh brines.Master of Science in Life Sciences
11
Asghar, Muhamamd Sajid Ali. "In-situ generation and dissolution of nano structures by liquid and dry electron irradiation method". Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/22497/.
12
Bedson, Thomas Robert. "Nanostructure fabrication using electron beam irradiation of organometallic compounds". Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369333.
13
Khorsandi, Behrooz. "Modeling of displacement damage in silicon carbide detectors resulting from neutron irradiation". Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1173103438.
14
Aygun, Sukran Gizem. "Detection Of Gamma Irradiated Spices With Osl Method And Its Reliability". Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612333/index.pdf.
Abstract (sommario):
The aim of this current work is to analyze the behavior of OSL (Optically
Stimulated Luminescence) signals of irradiated spices with respect to time,
temperature, origin and the type. Throughout the experiments, 3 different type
spices from four different origins were stored at 4°C and 25°
C for six months after irradiation. During experiments, unirradiated red pepper, thyme and cumin samples were analyzed by using OSL technique in order to determine the background OSL signal values of samples. Samples were irradiated 10 kGy by Cobalt 60 gamma source in TAEK (Turkey Atomic Energy Association). After irradiation process, OSL signal values of different samples were analyzed according to the given parameters. In order to determine the effect of temperature on OSL signal loss, temperature (4°
C- 25°
C) was set as storage temperature. The analyses were made monthly. According to the statistical analyses (ANOVA- General Linear Model), origin and type of samples were detected as significant parameters of design experiment. Time and temperature effect on OSL signal loss changed with respect to origin and type of samples. After six months storage period, OSL signal was lost for most of the origin and sample type. At the end of sixth month, an ESR analysis was performed to detect the accuracy of the OSL technique. With respect to the results of these experiments, it was seen that, due to optical fading, most of the samples was observed as unirradiated by OSL technique, however ESR analyze the samples as irradiated at the end of sixth month. Irradiation had a detrimental effect on the microbiological load of the samples and resulted 6 log reduction on the microbial population. After irradiation, no colony formation was observed in total bacteria and yeast- mold count. During six month period, no injury recovery was observed.
15
Bouillaud, Pascal. "Irradiation aux ions lourds de films minces nanocristallins d'alliages FeCo et FeAl". Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37612171v.
16
HERNANDES, ANTONIO C. "Caracterizacao do campo de radiacao numa instalacao para pesquisa em BNCT utilizando o metodo de Monte Carlo codigo MCNP-4B". reponame:Repositório Institucional do IPEN, 2002. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10997.
Abstract (sommario):
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
17
Ogura, Kengo. "Efficacy of salvage stereotactic radiotherapy for recurrent glioma: impact of tumor morphology and method of target delineation on local control". Kyoto University, 2014. http://hdl.handle.net/2433/188675.
18
Pham, thi Tam ngoc. "Caractérisation et modélisation du comportement thermodynamique du combustible RNR-Na sous irradiation". Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4044/document.
Abstract (sommario):
Au-dessus d'un taux de combustion seuil ≥ 7 at %, les produits de fission volatils Cs, I, et Te ou métalliques (Mo) sont partiellement relâchés hors du combustible et finissent par constituer une couche de composés de PF qui remplit progressivement le jeu existant entre la périphérie de la pastille et la surface interne de la gaine en acier inoxydable. Nous appelons cette couche JOG pour Joint Oxyde-Gaine. Mon sujet de thèse est axé sur l'étude thermodynamique du système (Cs, I, Te, Mo, O) + (U, Pu) ainsi que sur l'étude de la diffusion de ces produits de fission à travers le combustible vers le jeu combustible-gaine pour former le JOG.L'étude thermodynamique constitue la première étape de mon travail. Sur la base d'une analyse critique des données expérimentales issues de la littérature, les systèmes Cs-Te, Cs-I, Cs-Mo-O ont été modélisés par la méthode CALPHAD. En parallèle, une étude expérimentale a été entreprise pour valider la modélisation CALPHAD du système binaire Cs-Te. Dans une deuxième étape, les données thermodynamiques résultant de la modélisation CALPHAD ont été introduites dans la base de données du code de calcul thermodynamique ANGE (code interne au CEA dérivé du logiciel SOLGASMIX) dont la finalité est le calcul de la composition chimique du combustible irradié. Dans une troisième étape, le code de calcul thermodynamique ANGE (Advanced Numeric Gibbs Energy minimiser) a été couplé avec le code de simulation du comportement thermomécanique du combustible des RNR-Na GERMINAL V2For a burn-up higher than 7 at%, the volatile FP like Cs, I and Te or metallic (Mo) are partially released from the fuel pellet in order to form a layer of compounds between the outer surface of the fuel and the inner surface of the stainless cladding. This layer is called the JOG, french acronym for Joint-Oxyde-Gaine.My subject is focused on two topics: the thermodynamic study of the (Cs-I-Te-Mo-O) system and the migration of those FP towards the gap to form the JOG.The thermodynamic study was the first step of my work. On the basis of critical literature survey, the following systems have been optimized by the CALPHAD method: Cs-Te, Cs-I and Cs-Mo-O. In parallel, an experimental study is undertaken in order to validate our CALPHAD modelling of the Cs-Te system. In a second step, the thermodynamic data coming from the CALPHAD modelling have been introduced into the database that we use with the thermochemical computation code ANGE (CEA code derived from the SOLGASMIX software) in order to calculate the chemical composition of the irradiated fuel versus burn-up and temperature. In a third and last step, the thermochemical computation code ANGE (Advanced Numeric Gibbs Energy minimizer) has been coupled with the fuel performance code GERMINAL V2, which simulates the thermo-mechanical behavior of SFR fuel
19
Jaouen, Christiane. "Etude des mécanismes des transformations de phase induites par irradiation aux ions dans les systèmes métalliques". Poitiers, 1987. http://www.theses.fr/1987POIT2019.
Abstract (sommario):
Etude par mesure de conductivite electrique, par retrodiffusion rutherford et par microscopie ionique en transmission des differents aspects du melange ionique dans le systeme mt/al (mt=fe, co, ni) et fe-mg. Analyse des differents facteurs controlant la formation d'une phase et celle d'une phase amorphe. Analyse des mecanismes de transformation cristal-amorphe de l'alliage ni::(50)al::(50) en couche mince. Influence des parametres d'irradation sur cette transformation
20
Ozaltun, Hakan. "An Energy Based Fatigue Lifing Method for In-Service Components and Numerical Assessment of U10Mo Alloy Based Fuel Mini Plates". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1309210033.
21
Narayanan, Sankar. "Atomistic and multiscale modeling of plasticity in irradiated metals". Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53004.
Abstract (sommario):
Irradiation induces a high concentration of defects in the structural materials of nuclear reactors, which are typically of body-centered cubic Iron (BCC Fe) and its alloys. The primary effect of irradiation is hardening which is caused by the blocking of dislocations with defects and defect clusters like point defects, self-interstitial loops, and voids. The dislocation-defect interactions are atomistic in nature due to the very small length and time scales involved, i.e., of the order of nanometers and picoseconds. To predict the effect of dislocation-defect interactions on the macroscopic mechanical and plastic behavior of the material, it is critically important to develop robust coupling schemes by which accurate atomic level physics of the rate-limiting kinetic processes can be informed into a coarse-grained model such as crystal plasticity. In this thesis we will develop an atomistically informed constitutive model. Relevant atomistic processes are identified from molecular dynamics simulations. The respective unit process studies are conducted using atomistic reaction pathway sampling methods like Nudged Elastic Band method. Stress-dependent activation energies and activation volumes are computed for various rate-liming unit processes like thermally activated dislocation motion via kinkpair nucleation, dislocation pinning due to self interstitial atom, etc. Constitutive laws are developed based on transition state theory, that informs the atomistically determined activation parameters into a coarse-grained crystal plasticity model. The macroscopic deformation behavior predicted by the crystal plasticity model is validated with experimental results and the characteristic features explained in the light of atomistic knowledge of the constituting kinetics. We also investigate on unique irradiation induced defects such as stacking fault tetrahedra, that are formed under non-irradiated condition. This thesis also includes our work on materials with internal interfaces that can resist irradiation induced damage. Overall, the research presented in this thesis involves the implementation and development of novel computational paradigm that encompasses computational approaches of various length and time scales towards robust predictions of the mechanical behavior of irradiated materials.
22
Gery, Guillaume. "Procédés d'implantation moléculaire laser : implantation et réactivité de fluorophores dans des poly(méthacrylates) d'alkyles par irradiation laser à excimère XeF". Vandoeuvre-les-Nancy, INPL, 1997. http://www.theses.fr/1997INPL062N.
Abstract (sommario):
L’implantation moléculaire tire son origine de l'ablation par irradiation laser de films polymères dopés par une molécule photosensible. Le dispositif expérimental fait intervenir deux films polymères superposés en contact direct irradiés par une impulsion laser à excimère (XeF). Le film source est un film dopé en molécules photosensibles tandis que le film d'implantation peut être non dopé ou dopé avec une molécule susceptible de réagir avec la molécule dopante du film source, mais transparente à la longueur d'onde du faisceau laser. Les molécules du film source sont excitées, convertissent l'énergie du faisceau laser en énergie calorifique puis sont implantées dans le film en contact. L'étude a porté sur l'implantation d'anthracène et de dicyanoanthracène dans des films de poly(méthacrylates d'alkyles) de différentes températures de transition vitreuse. L’analyse de la quantité de molécules implantées en fonction de la température du film source suit une loi d'Arrhenius et indique l'origine diffusionnelle du processus d'implantation (activation thermique). Un modèle, prenant en compte le coefficient de diffusion et l'énergie d'activation de diffusion de l'anthracène dans le polymère, est en bon accord avec les résultats expérimentaux. L’implantation moléculaire est ensuite appliquée à la formation d'un complexe par transfert de charge dans une matrice polymère. L’anthracène et le tetracyanobenzène ne représentent pas un bon couple de complexassions, du a un rendement quantique de fluorescence du complexe très faible (gênant sa détection par spectrofluorimétrie). En revanche, le couple dicyanoanthracène/hexamethylbenzène a permis de mettre en évidence la complexation des deux constituants dans la matrice, ce qui permet de dégager des perspectives originales pour la chimie dans les polymères puisque l'implantation moléculaire permet des réactions dans un volume parfaitement défini d'un film polymère solide sans l'utilisation de solvant.
23
MASSICANO, FELIPE. "Quantificacao de imagens tomograficas para calculo de dose em diagnose e terapia em medicina nuclear". reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9601.
Abstract (sommario):
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
24
SOUZA, GREGORIO S. de. "Projeto e implantação de melhorias na blindagem biológica da instalação pra estudos em BNCT". reponame:Repositório Institucional do IPEN, 2011. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9967.
Abstract (sommario):
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
25
YORIYAZ, HELIO. "Desenvolvimento de uma metodologia computacional para calculos em dosimetria interna". reponame:Repositório Institucional do IPEN, 2000. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10791.
Abstract (sommario):
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
26
Boukhalfa, Abdelkrim. "Combustion a l'etude de la structure scalaire dans les flammes turbulentes premelangees du type bunsen". Orléans, 1988. http://www.theses.fr/1988ORLE2043.
Abstract (sommario):
Determination des champs moyens et fluctuant de la masse volumique, des densites de probabilite, des hauteurs de flammes, des epaisseurs apparentes, des spectres de puissance, des echelles integrales et des frequences de passage du front de flamme. Comparaison des resultats experimentaux avec les preditions de modeles theoriques
27
MIYAKAWA, WALTER. "Laser de CuHBr em tecidos dentais duros". reponame:Repositório Institucional do IPEN, 2004. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11201.
Abstract (sommario):
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
28
MAIDANA, NORA L. "Medidas de seccoes de choque para reacoes de captura de neutrons no sup(57)Co, sup(137)Cs e sup(241)Am considerando a formacao de estados isomericos". reponame:Repositório Institucional do IPEN, 2000. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10798.
Abstract (sommario):
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
29
Li, Xiaohua. "Etude des processus de formation des microcavités dans les alliages ferritiques des cuves de réacteurs nucléaires". Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10010.
Abstract (sommario):
Les cuves des reacteurs a eau pressurisee se fragilisent sous irradiation neutronique. L'etude des mecanismes responsables donne des informations sur la duree de vie de ces cuves, ainsi que le choix des aciers constitutifs. De nombreuses interpretations font intervenir la precipitation sous irradiation, ou la formation de grosses cavites. Pour notre part, nous avons utilise la technique consistant a mesurer la duree de vie de positions injectes dans les materiaux soumis a l'etude. Cette technique est interessante pour traiter ce probleme, car les positions sont attires et pieges aux espaces vides de l'echantillon. Dans les cas favorables, elle permet l'evaluation de la taille et la concentration des espaces vides, dans une gamme bien inferieure a la limite de detection des meilleurs microscopes. Ainsi, la technique des positions excelle dans une gamme de concentration de 0. 1 a 100 lacunes par million d'atomes, et pour des tailles de cavites comprises entre 0. 5 et 50 volumes atomiques. Les irradiations etaient simulees par une dose standard de 10#1#9 electrons par cm#-#2, a 27, 150 et 288c, obtenus avec l'accelerateur d'electrons de 3 mev du ceng. Nos resultats different notablement des publications des autres ecoles, neanmoins nous precisons que nos resultats sont valables sous irradiation electronique. Nous avons mis en evidence que le phenomene essentiel n'est pas la precipitation sous irradiation, mais le stockage transitoire d'une forte concentration lacunaire par piegeage aux impuretes cu, c ou n. La liberation de celle-ci formerait de petites cavites de 6 a 10 lacunes, qui par elles memes ne semblent pas responsables de la fragilisation. Mais ces cavites grossissent dangereusement (taille superieures a 50 volumes atomiques), si des dislocations non decorees sont presentes. De telles dislocations peuvent etre introduites fortuitement par un ecrouissage accidentel et une temperature d'irradiation legerement inferieure a la temperature de fonctionnement, a savoir 288c. (les dislocations resultant des traitements thermiques et presentes en grand nombre dans les alliages industriels n'ont pas d'influence car elles sont fortement decorees par du carbone. ) l'azote exerce une action importante. Son etude est difficile car son action est souvent confondue avec celle du carbone. Nous avons dispose d'echantillons de fen, avec une teneur en carbone inferieure a 10#-#5 c/at. , ou l'azote avait ete introduit en phase liquide. Dans ce cas, l'azote stabilise considerablement le reseau de dislocations et favorise sous irradiation la germination de cavites de grandes tailles
30
Mayoral, Claude. "Etude experimentale et simulation numerique de l'emission auger de l'aluminium sous bombardement d'ions argon". Toulouse 3, 1987. http://www.theses.fr/1987TOU30053.
Abstract (sommario):
Etude des distributions d'energie des electrons secondaires emis lors de l'interaction entre des ions argon monocharges et des cibles d'aluminium. Les structures auger l::(23) de l'aluminium apparaissant sur les spectres d'energie, ont ete plus particulierement etudiees. Calcul des rendements auger par simulation de cascades de collisions (code marlowe). Description de l'emission et de l'echappement des electrons auger par une methode de monte carlo
31
Vargas, Fabian Luis. "Amélioration de la sureté de fonctionnement de systèmes spatiaux basée sur le contrôle de courant". Grenoble INPG, 1995. http://www.theses.fr/1995INPG0063.
Abstract (sommario):
La fiabilite des systemes spatiaux est difficile a assurer lorsqu'il s'agit de prendre en compte les effets de la radiation. Plusieurs consequences sont possibles quand un circuit integre (ci) est expose a la radiation ionisante, toutefois aucune d'elles n'est particulierement desirable. Les effets commencent par une lente et implacable degradation de la performance du circuit, allant de la generation spontanee des erreurs fonctionnelles jusqu'au claquage total du circuit. En plus des effets de la radiation ionisante, il est aussi a present reconnu par la communaute internationale que les aleas (single event upsets - seus) representent une autre menace potentielle a la fiabilite des cis dans les environnements spatiaux. Ce sujet est d'importance considerable aujourd'hui, car au fur et a mesure que les technologies de cis atteignent des dimensions sousmicroniques, les effets des rayons cosmiques ont tendance a generer de plus en plus de seu sur les memoires des systemes electroniques. D'autre part, le test par courant a montre son efficacite en detectant des fautes difficilement decelables par le test logique conventionnel. Le test par courant peut donc ameliorer sensiblement la qualite et reduire le cout de production des cis cmos. Dans ce but, cette these presente une approche qui estime le courant de repos (i#d#d#q) en se basant sur des parametres de qualite comme l'immunite au bruit ainsi que la vitesse du ci. En sachant que la radiation ionisante degrade ces deux parametres des cis cmos, cette approche est ainsi tres appropriee pour ameliorer la qualite du test de fabrication du produit qui sera utilise dans des applications spatiales. Cette these presente egalement deux approches qui ont pour but la conception des systemes electroniques tolerants aux effets de la radiation. La premiere approche permet la conception de circuits tolerants aux effets de la dose totale, tandis que la deuxieme approche permet la conception de memoires cmos sram tolerantes aux aleas. Ces deux approches sont basees sur la combinaison de test par courant, realise par des capteurs de courant sur silicium, et de techniques de redondance au niveau materiel
32
Tewfik, Ihab Hamdy. "Rapid methods for the identification of gamma irradiated lipid containing foods". Thesis, London South Bank University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267387.
33
Benkaddour, Abdelkhalek. "Proprietes des defauts d'irradiation dans des alliages austenitiques fer-chrome-nickel et des alliages ferritiques fer-chrome : influence de la teneur en chrome". Paris 6, 1987. http://www.theses.fr/1987PA066144.
Abstract (sommario):
Etude par mesure de resistivite electrique, de l'influence de la teneur en chrome sur la production et la migration des defauts ponctuels dans les alliages fe-25%ni-8 a 16%cr(% en poids) et fe-5 a 15%atcr soumis a une irradiation par electrons a 21k. Influence d'un recuit sur ces defauts d'irradiation. Interpretation des resultats par un modele de restauration
34
Berroudji, Sid-Ahmed. "Cinétiques de mise en ordre à courte distance et caractéristiques des lacunes et des autointerstitiels dans des alliages [gamma]-FeNiCr". Grenoble 1, 1988. http://www.theses.fr/1988GRE10095.
Abstract (sommario):
Etude des cinetiques de mise en ordre dans les alliages fe::(59)ni::(25)cr::(16) et fe::(9)ni::(75)cr::(16) par mesure de resistivite electrique. Determination des caracteristiques des lacunes et autointerstitiels par les techniques de trempe a l'helium liquide, de mesure de resistivite lors des cycles alternes de chauffage et de trempe ou lors de cycles continus. Evaluation des enthalpies de formation, de migration et d'autodiffusion. Influence de la composition. Analyse des sursaturations dynamiques de defauts lors de l'irradiation. Determination des frequences de saut des autointerstitiels et de leur enthalpie en fonction de la composition chimique
35
Brulay, Guillaume. "Optimisation de la quantité de radicaux générés dans les silices hybrides mésoporeuses : synthèse, caractérisation, application". Electronic Thesis or Diss., Aix-Marseille, 2022. http://www.theses.fr/2022AIXM0575.
Abstract (sommario):
Le but de cette étude est de développer des silices mésoporeuses hybrides possédant une concentration en radicaux transitoires élevée pour permettre des application notamment en RMN-PDN. Tout d'abord, il a été montré que des rendements quantitatifs en centres paramagnétiques pouvaient être obtenus lors de réactions photochimiques unimoléculaires. La synthèse de nouveaux précurseurs ainsi qu'une optimisation des conditions de photolyse ont permis d'obtenir des silices fonctionnalisées par des radicaux transitoires avec des rendements de bons à quantitatifs. La différence de réactivité des divers précurseurs de radicaux a été rationalisée, une adéquation entre les mécanismes de fragmentation et les contraintes relatives à leur environnement dans les murs des silices est indispensable pour l'obtention de bons rendements. Ces systèmes polyradicalaires ont été caractérisés par spectroscopie RPE. Leur temps de vie élevé rend possible l'évaluation de ces nouveaux radicaux "persistant" en tant qu'agent de polarisation pour la RMN-PDNThe aim of this work was the development of hybrid mesoporous silicas composed with high concentration of embedded transient radicals in order to use them as polarizing agent in DNP-NMR. First of all, quantitative yield in paramagnetic centers were obtained from unimolecular processed carried out under photoirradiation. The synthesis and optimization of photolysis conditions allowed to obtain functionalized silicas by transient radicals from good to quantitative yields. The reactivity difference of radical precursors was rationalized by the fragmentation mechanism and environmental constraints inside the walls of the silica structure which provided high yields. Polyradical systems were characterized by EPR spectroscopy. High life-time allows the evaluation of these new "persistent" radical species as polarizing agent for DNP-NMR
36
Flower, Emily Elizabeth, e not supplied. "Comparison of Two Planning Methods for Heterogeneity Correction in Planning Total Body Irradiation". RMIT University. Applied Sciences, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20070511.163728.
Abstract (sommario):
Total body irradiation (TBI) is often used as part of the conditioning process prior to bone marrow transplants for diseases such as leukemia. By delivering radiation to the entire body, together with chemotherapy, tumour cells are killed and the patient is also immunosupressed. This reduces the risk of disease relapse and increases the chances of a successful implant respectively. TBI requires a large flat field of radiation to cover the entire body with a uniform dose. However, dose uniformity is a major challenge in TBI. (AAPM Report 17) The ICRU report 50 recommends that the dose range within the target volume remain in the range of -5% to +7%. Whilst it is generally accepted that this is not possible for TBI, it is normally clinically acceptable that ±10% of the prescribed dose to the whole body is sufficiently uniform, unless critical structures are being shielded. TBI involves complex dosimetry due to the large source to treatment axis distance (SAD), dose uniformity and flatness over the large field, bolus requirements, extra scatter from the bunker walls and floor and large field overshoot. There is also a lack of specialised treatment planning systems for TBI planning at extended SAD. TBI doses at Westmead Hospital are prescribed to midline. Corrections are made for variations in body contour and tissue density heterogeneity in the lungs using bolus material to increase dose uniformity along midline. Computed tomography (CT) data is imported into a treatment planning system. The CT gives information regarding tissue heterogeneity and patient contour. The treatment planning system uses this information to determine the dose distribution. Using the dose ratio between plans with and without heterogeneity correction the effective chest width can be calculated. The effective chest width is then used for calculating the treatment monitor units and bolus requirements. In this project the tissue heterogeneity corrections from two different treatment planning systems are compared for calculating the effective chest width. The treatment planning systems used were PinnacleTM, a 3D system that uses a convolution method to correct for tissue heterogeneity and calculate dose. The other system, RadplanTM, is a 2D algorithm that corrects for tissue heterogeneity using a modified Batho method and calculates dose using the Bentley - Milan Algorithm. Other possible differences between the treatment planning systems are also discussed. An anthropomorphic phantom was modified during this project. The chest slices were replaced with PerspexTM slices that had different sized cork and PerspexTM inserts to simulate different lung sizes. This allowed the effects of different lung size on the heterogeneity correction to be analysed. The phantom was CT scanned and the information used for the treatment plans. For each treatment planning system and each phantom plans were made with and without heterogeneity corrections. For each phantom the ratio between the plans from each system was used to calculate the effective chest width. The effective chest width was then used to calculate the number of monitor units to be delivered. The calculated dose per monitor unit at the extended TBI distance for the effective chest width from each planning system is then verified using thermoluminescent dosimeters (TLDs) in the unmodified phantom. The original phantom was used for the verification measurements as it had special slots for TLDs. The isodose distributions produced by each planning system are then verified using measurements from Kodak EDR2 radiographic film in the anthropomorphic phantom at isocentre. Further film measurements are made at the extended TBI treatment SAD. It was found that only the width of the lungs made any significant difference to the heterogeneity correction for each treatment planning system. The height and depth of the lungs will affect the dose at the calculation point from changes to the scattered radiation within the volume. However, since the dose from scattered radiation is only a fraction of that from the primary beam, the change in dose was not found to be significant. This is because the calculation point was positioned in the middle of the lungs, so the height and depth of the lungs didn't affect the dose at the calculation point. The dose per monitor unit calculated using the heterogeneity correction for each treatment planning system varied less than the accuracy of the TLD measurements. The isodose distributions measured by film showed reasonable agreement with those calculated by both treatment planning systems at isocentre and a more uniform distribution at the extended TBI treatment distance. The verification measurements showed that either treatment planning system could be used to calculate the heterogeneity correction and hence effective chest width for TBI treatment planning.
37
Banci, Gabriele. "New methods for rapid h/d exchange and related processing using microwave irradiation". Thesis, Cardiff University, 2013. http://orca.cf.ac.uk/49931/.
Abstract (sommario):
Microwave mediated H/D exchanges have been studiedin this thesis. The purpose of these studies is to validate an efficient method for replacing hydrogen by deuterium in molecules with biological and pharmaceutical activity. As a result of this, such deuterated compounds would be helpful during the investigation of pharmacological and metabolic studies. At the beginning of this research, aniline derivatives weremainly employed as substrates. Their importance in drug synthesis makes the corresponding labelled compounds useful as building blocks. During these studies a Pt catalyst wasemployed. As a consequence of its strong efficiency, fully deuterated compounds were obtained in many cases. In the first part of this research, yields were based on ratios between non-deuterated and deuterated original compounds. However, due to solubility problems and metal-complex formation, this parameter was found to vary considerably. Therefore, an analytical method, involving introduction of a non-deuterated acetyl group to the labelled substratewas employed, so that the acetyl group could be regarded as an internal reference for 1HNMR integration, allowing quantification of deuterium incorporation at all positions in the molecular structure. Kinetic experiments have also enabled the best conditions to be defined for the exchange reactions. Lastly, as a consequence of a reductive process, Pt0 has been recognized as a serious problem for calculating final yield. An appropriate method for eliminating it from the solutions has therefore been applied. A valid Pt mediated H/D mechanism has been proposed, based on suggestions from the literature that Pt can move around both aromatic rings and alkyl side chains. To try to get evidence for such a mechanism, different alkylanilines have been used, giving useful information regarding metal activity, particularly with respect to steric aspects. In the last part of the work, as a consequence of its importance in pharmaceutical chemistry, heterocyclic derivatives have been investigated. Satisfactory results have permitted the method to be explioted for some relevant drugs.
38
BRANCO, ISABELA S. L. "Estudo dos efeitos na dose devido à heterogeneidade em braquiterapia com fontes de I125". reponame:Repositório Institucional do IPEN, 2017. http://repositorio.ipen.br:8080/xmlui/handle/123456789/28045.
Abstract (sommario):
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A braquiterapia de baixas taxas de dose realizada com sementes de 125I tem sido amplamente usada por décadas em variados sítios anatômicos, com bons resultados clínicos. O advento de algoritmos para cálculo de dose baseados em modelos (MBDCAs) permitiu aprimorar oestudo de deposição da dose considerando heterogeneidades como diferentes tecidos, órgãos,aplicadores com composições diferentes da água, proporcionando a análise em geometriascomplexas. As simulações matemáticas realizadas através destes algoritmos possibilitam odesenvolvimento de modelos fisicamente mais acurados que estendem sua aplicabilidade àverificação de sistemas de planejamento em braquiterapia. Neste trabalho foram estudadasconfigurações de objetos simuladores confeccionados para medidas experimentais e simuladosatravés do código MCNP de Monte Carlo a fim de observar as diferenças ocasionadas pelaintrodução de heterogeneidades quando presentes fontes de 125I de baixa taxa de dose. Para estepropósito, distintas as vertentes do tema foram abordadas, entre elas o estudo da influênciaexercida pelos parâmetros de densidade e composição dos materiais tecido equivalentes. Osresultados obtidos demonstraram que, o efeito que a composição de cada um dos materiaisexerce sobre a deposição de dose é mais expressivo que o efeito de sua densidade. Em outroestudo, foi estabelecida uma relação para estimar, de maneira simples, a dose de atenuação detecidos heterogêneos a partir da aferição ou simulação da dose obtida num objeto simuladorconstituído por PMMA, metodologia que pode ser desenvolvida e implementada na rotina clínica.Para complementação das análises dos estudos dosimétricos com a presença deheterogeneidades, foi realizada a validação da geometria simulada da semente de 125I, onde sereproduziu a metodologia de cálculo dosimétrico presente no TG-43 da AAPM. Além disto, foirealizado o estudo teórico da dependência energética dos dosímetros termoluminescentes paraanalisar a variação de sua resposta conforme a energia. A metodologia desenvolvida para oestudo dos efeitos da heterogeneidade na deposição de dose é recomendada na avaliação desistemas de planejamento computadorizados que possuem algoritmos de cálculo de dosebaseados em modelos, quando utilizadas fontes de 125I com baixa taxa de dose, de forma acontribuir na incorporação de novas estimativas de doses com maior acurácia.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
39
White, Carla A. "Design of an experimental irradiation facility based on 50-mg ²⁵²Cf for ¹⁰B-enhanced ²⁵²Cf brachytherapy". Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/17303.
40
Short, Susan Christine. "New methods to overcome radioresistance". Thesis, Institute of Cancer Research (University Of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313289.
41
MURA, LUIS F. L. "Medidas de taxas de reacao nuclear e de indices espectrais ao longo do raio das pastilhas combustiveis do reator IPEN/MB-01". reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9617.
Abstract (sommario):
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
42
Diallo, Mouhamet. "Estimation et prédiction de l’ensoleillement en zone intertropicale Improving the Heliosat-2 Method for Surface Solar Irradiation Estimation Under Cloudy Sky Areas Assessing GFS and IFS global weather preduction and numerical model forecast accuracy in the intertropical zone and for tropical climates Calibration of WRF irradiance in French Guiana and comparison with AROME forecasts". Thesis, Guyane, 2018. http://www.theses.fr/2018YANE0009.
Abstract (sommario):
La Guyane est un territoire d’outre-mer, situé en zone intertropicale (ZIT). Cette zone est le lieu de phénomènes de convections intenses. De ce fait, l’énergie solaire incidente au sol est très variable ce qui constitue un frein à son exploitation à grande échelle. La question de recherche étudiée dans ce manuscrit est : comment peut-on améliorer les estimations et prédictions de rayonnement au sol en ZIT de façon à augmenter le taux de pénétration dans le réseau électrique de cette énergie renouvelable intermittente ? Afin de répondre à cette question, nous avons utilisé deux outils. Le code Héliosat-II (HII) et le modéle de prévisions météorologiques Weather and research forecast (WRF). Nous avons utilisé ces outils de manière à améliorer les estimations et prévisions de rayonnement global au sol (IGH) dans la ZIT. La première partie de ce manuscrit présente le contexte de la thèse. La seconde présente une modification d’H-II permettant d’améliorer les estimations d’IGH par une modélisation explicite de l’absorption de nuages. Ces estimations améliorées donnent ainsi des outils décisionnels permettant de situer au mieux une centrale solaire en fonction du potentiel solaire du site et des systèmes services avoisinants. La seconde partie traite dans un premier temps de la précision des prévisions des modèles globaux IFS et GFS (i.e integrated forecast system, global forecast system GFS) en ZIT. Ces produits téléchargés sont validés par comparaison avec des mesures in situ de trois pays situés dans la ZIT et caractérisés par des climats tropicaux. Cette étude permet de combler un vide dans l’étude des prévisions d’IGH des modèles globaux en ZIT. Nous proposons ensuite une méthode générique permettant de calibrer le modèle WRF en ZIT. Cette méthodologie vise à limiter le nombre de simulations à effectuer en sélectionnant et en faisant varier uniquement les paramètres ayant le plus d’influence sur le rayonnement au sol en ZIT. Pour valider cette méthodologie nous avons comparé les prévisions d’IGH du modelé WRF calibré avec celle du modelé AROME ainsi qu’avec des mesures in situ en Guyane. La quatrième partie présente l’utilisation d’une méthode hybride ensembliste variationnelle d’assimilation de donnée permettant d’améliorer les prévisions de rayonnements en ZIT. Cette méthode initialement utilisée pour améliorer la description de phénomènes convectifs extrêmes tels que prévision de la trajectoire des cyclones est pour la première fois appliquée pour améliorer les prévisions d’IGH. Cette méthodologie appliquée à la ZIT fournie alors des prévisions améliorées d’IGH permettant ainsi une gestion améliorée de centrale solaireFrench Guiana is a French territory located in the inter-tropical zone (ITZ). The ITZ is an area with highly variable dynamic in which we encounter significant amounts of convective clouds. Consequently the solar energy available at the ground is highly variable. This variability causes economical and technical challenges to fully exploit this resource. This thesis dissertation aims to answer the following scientific issue: How could the solar irradiance be assessed and forecast accurately in the ITZ to increase the penetration rate of this intermittent renewable energy into the electricity grid? To answer this scientific issue, we use two tools: Heliosat-II (H-II) and Weather and research forecast (WRF). We used these tools in order to produce improved GHI estimates in the inter-tropical zone. The first chapter introduces the thesis and the research issue. The second chapter presents a modification to H-II; with this modification H-II can account for cloud absorption. The GHI estimates from modified H-II provide therefore tools for decision making in the ITZ. These tools allow one identifying the most suitable locations to install solar facilities in the ITZ with respect to both solar potential and surrounding facilities that favor grid stability. In the third chapter we study first the accuracy in the ITZ of the GHI forecasts from integrated forecast system (IFS) and global forecast system (GFS) numerical weather prediction model (NWP). We validate the accuracy of these downloaded products by comparison with ground measurements from three countries located in the ITZ that have tropical climate. This study aims to fill the gap with regard to the accuracy of global NWP model in the ITZ. Second we propose a methodology to calibrate WRF to produce improved GHI forecasts in the ITZ. The goal is to restrain and select the minimum number of simulations to run, to obtain improved GHI forecasts compared to a non-calibrated model. This methodology to calibrate WRF is validated in French Guiana by comparison with the GHI forecasts of AROME NWP model and ground measurements. The fourth chapter deals with the use of an hybrid 3D variational (3D-Var) ensemble transform Kalman filter (ENTKF) to further improve the GHI forecasts of calibrated WRF in the ITZ. This methodology originally used in the tracking of extreme convection events such as cyclones is applied for the first time for GHI forecasts. This methodology applied to the ITZ therefore allows obtaining improved GHI forecasts which makes easier monitoring the electricity production from solar facilities
43
Anderson, Cody. "Benchmarking of different solar spectra quality control methods". Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/201343/1/Cody_Anderson_Thesis.pdf.
Abstract (sommario):
This thesis addresses the current lack of quality control tools available to assess solar spectral irradiance measurements. Spectral measurements are very data rich and can be overwhelming to manually check. The purpose of this project was aimed towards developing a solar spectra data screening method and ultimately create an automated quality control and assurance tool. Measured spectra were assessed as good or bad by comparing them to the spectral model AeroSMARTS. Efficacy of the novel methodologies was demonstrated by cross comparison with a manually screened reference dataset.
44
Dreiling, Jeremy B. "An evaluation of ultraviolet germicidal irradiation (UVGI) technology in health care facilities". Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/651.
45
Fan, Xiaohu. "Optimization of biodiesel production from crude cottonseed oil and waste vegetable oil conventional and ultrasonic irradiation methods /". Connect to this title online, 2008. http://etd.lib.clemson.edu/documents/1239895502/.
46
van, Haandel Andre. "Irradiation as an alternative phytosanitary treatment for Arhopalus ferus and Hylurgus ligniperda". Thesis, University of Canterbury. School of Forestry, 2014. http://hdl.handle.net/10092/10506.
Abstract (sommario):
Wood products all require treatment to mitigate phytosanitary risk prior to exportation. The most common phytosanitary treatment applied to Pinus radiata logs is Methyl Bromide (MeBr). The Environmental Protection Agency (EPA) in 2010 stated that MeBr must not be release into the atmosphere past 2020. This poses a problem for New Zealand log exports. Radiation has been identified as a possible alternative phytosanitary treatment for export wood products.
This study aimed to quantify the effective dose of radiation necessary to sterilise two forest pest species; Arhopalus ferus and Hylurgus ligniperda. These species are representative of two different types of forestry pests; bark beetles (H. ligniperda) and wood borers (A. ferus). All applicable life stages for both species were tested.
Arhopalus ferus adults were the most susceptible life stage identified with an LD99 of 30.2Gy ± 13.5 Gy (95% confidence interval). Arhopalus ferus eggs were less susceptible with a LD99 of 750Gy ± 776Gy observed; however there is low confidence in this result due to a methodological issue in one treatment replicate. Hylurgus ligniperda eggs were observed to be less susceptible than A. ferus eggs with a LD99 of 289Gy ± 92Gy. Results for the other life stages were inconclusive due to poor control survival, however the information gained was used to develop improved methods for further experimentation, which is on-going and showing positive results so far.
The results of this experiment have indicated that radiation can be an effective method of sterilising forestry pests. To date radiation has not been used as phytosanitary risk mitigation for wood exports; however it is widely used for risk mitigation in agricultural products. Currently there remains a large amount of unknown information regarding, the effectiveness for irradiation of logs, the effective dose require for sterilisation of the most tolerant forestry pest and public acceptability of irradiation as a phytosanitary treatment. These knowledge gaps and an economic assessment must be completed before irradiation can be used as a phytosanitary risk mitigation technique for forestry products.
47
Taranu, Anca. "Femtosecond laser irradiation of Poly (methyl methacrylate) for refractive index modification and photochemical analysis". Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/femtosecond-laser-irradiation-of-poly-methyl-methacrylate-for-refractive-index-modification-and-photochemical-analysis(ac97a4a7-c614-47ed-a3e6-649477460351).html.
Abstract (sommario):
This thesis explores a new technique for investigating the photochemical mechanisms of femtosecond laser inscription of permanent photonic structures in Poly(methylmethacrylate) (PMMA). The refractive index (RI) structures were fabricated with a direct writing method without ablation, and analysed using a non-invasive method - namely: Raman mapping spectrometry. The writing conditions for the photonic structures under investigation are mainly represented by 800nm and 400nm wavelength with 44fs and 100fs pulse length and a low repetition rate in the kHz domain. The mass percentage of the induced monomer and end groups modification (MMA) as a measure of the modification of the ratio of C=C and C=O Raman transition varies linearly with the total fluence (total). The mass percentage of the induced monomer and end groups change is defined by the modification of normalised ratio of the Raman intensity of C=C bond (I(C=C)) and the Raman intensity of C=O bond (I(C=O)) which is denoted by I(C=C/C=O)n. The modification of this ratio is denoted by I (C=C/C=O)n and also by MMA. MMA varies linearly with total with a positive slope for both writing conditions due to the induced main chain scission and unzipping. If total increases by 1J/cm2, it is predicted an increase in MMA, by (1.550±0.11)x10-2 (cntsxcm2)/J, for the near infrared (NIR) irradiated samples that is higher than the increase of MMA for the ultraviolet (UV) irradiated sample that show a value of (1.9200.274)x10-3 ( (cntsxcm2)/J). The same trend was found for the variation of MMA with diffraction efficiency () for NIR irradiated structures and also for UV irradiated structures. If increases by 1cnt, it is predicted that there will be an increase in MMA, by (4.233±0.383) cnts for NIR irradiated samples that is lower than the increase of MMA for the UV irradiated sample that shows a value of (14.3922.477) cnts. The variation of MMA with is higher for UV irradiated samples than for NIR irradiated samples, and this indicates that the nonlinear absorption of two photons produces a larger percentage of the monomer and end groups than the nonlinear absorption of three photons. Gel Permeation Chromatography (GPC), which is a destructive analytical method, was applied only for the investigation of the time dependent behaviour of the molecular weight of the photonics structures which were written with the parallel writing technique using 775nm wavelength and 160fs pulse length that shows an increase of 66 in after seven days from the laser irradiation. Twenty-four hours after laser irradiation, the GPC results show that the weighted average molecular weight (Mw) of the exposed sample of 28,610,000 Daltons is about thirty times higher than the MW of the unexposed sample of 963,425 Daltons. This is an indication of the photo-cross-linking reaction. As a result of this reaction, the polymer chains link together through intermolecular forces to form a 3D network which produces an increase of molecular weight. It was also observed that there was a further decrease of molecular weight after three days to 437,441 Daltons due to main chain scission and unzipping. The main chain scission is actually the breaking of C-C bonds between structural units and the formation of radicals which further produce the monomer and end groups (MMA) through the unzipping reaction which leads to a decrease of the molecular weight. The main chain scission occurred with the greatest efficiency after three days following the end of irradiation, when the number of the main chain scissions (Ns) reached the maximum value of 1.193. An increase of molecular weight signifies an increase of the refractive index since the optical density has increased. The mechanical properties of PMMA optical fibres (e.g., Young's modulus) and of bulk PMMA (e.g., glass transition temperature) were investigated using Dynamical Mechanical Analysis (DMA) tests (e.g., stress-strain test and temperature ramp/frequency sweep test). These measurements were performed to study the effect of the manufacturing process that involves stretching and heating or cooling on the mechanical properties of PMMA optical fibres and unmodified PMMA material. T he ultimate aim of this section was to see the effect of the laser irradiation on the strain properties of an optical fibre sensor with gratings. The stress strain results show an increase of Young's modulus of the PMMA optical fibre of 5%, and this is an indication of decreased elasticity which is induced during the fabrication process. For a femtosecond laser irradiated region with UV wavelength, it is expected that there will be an increase of Young's modulus to 65%. This variation was obtained inthe research group from The Photon Science Institute by measuring Young's modulus for a diffraction grating which was written in PMMA with 180fs pulse length and 387nm wavelength and which was subjected to a strain. The elasticity was measured using the displacement of the first order diffracted beams as a result of a modification due to the applied strain [ ]. The temperature ramp/frequency sweep test shows an increase of glass transition temperature of the bulk PMMA of 54.12% which is also an indication of decreased elasticity induced during the fabrication process. A further increase in this temperature is expected for UV irradiated samples.
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Besar, Idris Bin. "Studies of the hazards of actinide contamination to man and methods of body measurement". Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323396.
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Rouillard, Hervé. "Etude de résolutions catalysées par des lipases sous irradiation micro-onde". Phd thesis, Université de La Rochelle, 2012. http://tel.archives-ouvertes.fr/tel-00815983.
Abstract (sommario):
La demande en composés chiraux est en plein essor ces dernières années. Pour accéder à leur synthèse, la biocatalyse, couplée à l'irradiation pourrait être une méthode innovante. Il existe en effet de nombreux cas dans la littérature où l'utilisation de micro-onde semble avoir un effet activateur sur l'efficacité enzymatique.Cependant, l'effet de l'irradiation micro-onde est mal compris et controversé. Le but de cette thèse était d'étudier l'impact de l'irradiation micro-onde sur des lipases, immobilisées ou non, en étudiant différentes réactions modèles, allant de la résolution d'alcools secondaires linéaires simples à la résolution de polyols complexes, et alcools polyfonctionalisés, par comparaison entre chauffage sous irradiation micro-onde (en conditions drastiques ou non) au chauffage classique. L'étude de l'irradiation micro-onde sur la stabilité enzymatique et sur paramètres intrinsèques de l'enzyme après modification des paramètres réactionnels a permis de mettre en évidence un rôle indéniable de l'irradiation micro-onde sur l'efficacité des réactions enzymatiques. Il a été possible d'une part de diminuer de façon importante les temps réactionnels, comparé au chauffage traditionnel,et d'autre part de contrôler efficacement l'énantio préférence et la sélectivité de la lipase pour l'obtention de molécules d'intérêt. Par des procédés innovants, l'impact de la puissance d'irradiation a été montré comme hautement dépendant du modèle réactionnel étudié. En optimisant les conditions réactionnelles pour obtenir les meilleures sélectivités et activités enzymatique sous irradiation micro-onde, la synthèse de a-hydroxyamides chiraux et de polyols parfaitement résolus a pu être entreprise de façon rapide, propre, tout en respectant les principes de chimie verte.
50
Fichou, Denis. "L'interface oxyde de zinc/électrolyte : étude des processus primaires". Paris 6, 1986. http://www.theses.fr/1986PA066259.