FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Em altas latitudes tem-se observado uma variaÃÃo na composiÃÃo bioquÃmica do plasma seminal (PS) de caprinos por influÃncia da estacionalidade. Em baixas latitudes essa variaÃÃo tem sido atribuÃda unicamente ao baixo valor nutricional das dietas na Ãpoca seca. Objetivou-se por meio deste estudo avaliar a ocorrÃncia de variaÃÃo na composiÃÃo bioquÃmica do PS de caprinos SPRD criados intensivamente no Estado do CearÃ, Brasil. O experimento foi conduzido nas instalaÃÃes do Dep. de Zootecnia da Universidade Federal do Cearà â UFC. Foram utilizados 20 bodes SPRD, alimentados segundo o NRC/caprinos (1981). Os ejaculados foram coletados semanalmente em vagina artificial e letroejaculador e em seguida avaliados, mensurados, centrifugados e separados o PS (sobrenadante) das cÃlulas espermÃticas (precipitado), sendo acondicionados em tubos eppendorffs a -18ÂC, durante um ano (Set/2005 a Ago/2006). Para realizaÃÃo das anÃlises as amostra semanais passaram a constituir um pool individual mensal, onde foram avaliadas as concentraÃÃes de Ca, P, Mg, PTt, AC e frutose. Foi observada variaÃÃo significativa (p<0,05) na composiÃÃo bioquÃmica do PS entre as Ãpocas do ano, registrando-se os nÃveis mais elevados dos parÃmetros bioquÃmicos na Ãpoca chuvosa. A variaÃÃo individual foi significativa (p<0,01), sà havendo interaÃÃo significativa, animal/Ãpoca para a frutose (p<0,05). O estudo das correlaÃÃes mostrou associaÃÃes significativas (p<0,0001) entre PTt, AC e frutose, entre os volumes de ejaculado e de PS, com os componentes, e de temperatura, umidade, precipitaÃÃo e ITU, com os parÃmetros bioquÃmicos do PS. Concluindo-se que a frutose à um bom parÃmetro bioquÃmico para o estudo da qualidade seminal, entretanto, mais estudos sÃo necessÃrios para identificar as causas desta variaÃÃo, e compreender melhor o papel da frutose, acido cÃtrico e proteÃnas totais no metabolismo espermÃtico. / Goat seminal plasma (SP) biochemical composition observed to very in high latitudes due to seasonality. In low latitudes this variation has been attributed only to the low nutritional value of diets in the dry period. The aims of this study were to evaluate the occurrence of variation in the SP biochemical composition of SPRD goats breed intensively in the State of CearÃ, Brazil. The experiment was carried out in the facilities of Dep. of Zootecnia of the Federal University of Cearà - UFC. Twenty male SPRD goats were used, they were fed according to NRC/goats (1981). Ejaculated were collected weekly in artificial vagina and eletroejaculador, and evaluated, measure, centrifuged and separated the SP (sobreswing) from the cells spermatic (precipitate), being stored in eppendorff tubes at -18ÂC, during one year (Sep/2005 the Aug/2006). For analyses purpose weekly sample were mixed to constitute a monthly individual pool, from which were evaluated the concentrations of Ca, P, Mg, PTt, CA and fructose. Significant variation was observed (p <0,05) in the biochemical composition of the SP among the periods of the year, registering the highest levels of biochemical parameters in the rainy period. The individual variation was significant (p <0,01), only having significant interaction animal/period to the fructose (p <0,05). The study of correlations showed significant associations (p <0,0001) among PTt, CA and fructose, among the ejaculate volume and of SP with the components, and of temperature, humidity, precipitation and ITU with the biochemical parameters of the SP. It is concluded that fructose is a good biochemical parameter for the study of seminal quality. However, more studies are necessary to identify the causes of this variation, and to better understand the role of the fructose, citric acid and total proteins in the metabolism spermatic.

L'objectif de ce projet porte sur le développement d'applications industrielles dans le domaine des traitements de surface par plasmas froids. L'emploi de cette technique pour le traitement de surface polymère reste de manière générale une alternative intéressante à la voie chimique. La création d'un réacteur prototype de grand volume répond aux attentes très diverses des industriels. Par son caractère évolutif, la plate-forme plasma froid du CRITT est un véritable outil de recherche dédié à l'industrie. Un des thèmes émergents de ces dernières années concerne l'utilisation des plasmas froids comme moyen alternatif pour la stérilisation des dispositifs médicaux. En effet, les techniques conventionnelles ne permettent pas une inactivation performante de certains micro-organismes pathogènes et les conditions de traitement parfois extrêmes n'assurent pas la pérennité du matériel médical. Préalablement à une validation clinique nécessaire à son développement en milieu industriel ou médical, ce nouveau procédé doit naturellement faire la preuve de son efficacité. L'étude réalisée présente les principaux mécanismes susceptibles d'expliquer l'inactivation d'un micro-organisme exposé au plasma. L'action en synergie de photons UV et d'espèces actives comme l'oxygène atomique confère à cette technologie une cinétique d'inactivation particulière. La production de ces agents actifs est optimisée par un diagnostic du plasma en spectroscopie optique, permettant ainsi d'atteindre des degrés d'inactivation très prometteurs. Même si l'efficacité du plasma n'est plus à démontrer, la problématique du conditionnement, qui fait partie intégrante d'un procédé, se pose toujours en milieu industriel. L'inhibition du plasma diffusant à travers un sachet poreux ne permet pas d'obtenir l'état stérile. Une solution consistant à générer un plasma induit dans un sachet, assurant ainsi un contact intime entre les espèces actives du plasma et le dispositif à stériliser, est donc discutée.

In this thesis electron generation is studied via laser plasma interaction known as laser wakefield acceleration in two regimes of weakly relativistic and highly relativistic laser intensity regimes. The plasma targets consisted of gas jets photonionized by rising edge of the laser pulse to densities as high as 10^20cm3. In the weakly relativistic regime, 210 mJ at 33 fs were focused to intensities of up to 310^18 Wcm2 on the gas targets of 2.4 mm length. In the highly relativistic regime, 3 J of energy compressed in 30 fs were delivered at intensity as high as 6.5 10^18 Wcm2 on targets of 2.4, 5, and 10 mm. Monoenergetic electrons in tens of MeV were observed in weakly relativistic regime, while electron energies as high as 300 MeV were observed in highly relativistic regime. Higher input laser intensity and prepulse levels were found to enhance electron production. Scaling of energy and stability of electron generation were also studied. / Photonics and Plasmas

This study uses the PIC (Particle-in-cell) method to simulate unsteady three-dimensional dynamics of particles in argon plasma under low pressure, high density, and weak ionization between two planar electrodes subject to a sudden biased voltage. Plasma has been widely used in materials processing, film manufacturing, nuclear fusion, lamps, etc. Properties of plasmas are also becoming important area for research. This work includes elastic collisions between electrons and neutrals, ions and neutrals, and inelastic collisions resulting in ionization from impacting neutrals by electrons, and charge exchange between ions and neutrals, and Coulomb collisions between electrons and ions. The model ignores magnetic field, secondary electron emission, recombination between ions and electrons, and assumes uniform distribution of the neutrals having velocity of Maxwellian distribution. The computed results show the effects of elastic and inelastic collisions on the characteristics of plasma and sheath (space charge region) in front of the workpiece surface. Unsteady mass, momentum and energy transport from the bulk plasma through sheath to the workpiece is confirmatively and exploratorily studied after successful comparison between PIC prediction and experimental data has been made.

An algorithm for modeling two species plasmas, which evolves the number density, flow velocity, and temperature equations coupled to Maxwell's electric and magnetic field equations, is discussed. Charge separation effects and the displacement current are retained. Mathematical derivations of normal modes in cold and hot plasmas, as represented by dispersion relations resulting from a linear analysis of the two fluid equations, are presented. In addition, numerical theory in relation to the ideas of geometry, temporal and spatial discretization, linearization of the fluid equations, and an expansion using finite elements is given. Numerical results generated by this algorithm compare favorably to analytical results and other published work. Specifically, we present numerical results, which agree with electrostatics, plasma oscillations at zero pressure, finite temperature acoustic waves, electromagnetic waves, whistler waves, and magnetohydrodynamics (MHD) waves, as well as a Fourier analysis showing fidelity to multiple dispersion relations in a single simulation. Final consideration is given to two species plasma stability calculations with a focus on the force balance of the initial conditions for a resistive MHD tearing mode benchmark and a static minimum energy plasma state.

Adequate control of the position of the plasma column within the STOR-M tokamak is a chief requirement in order for experimental quality discharges to be obtained. Optimal control over tokamak discharge parameters, including the plasma position, is very difficult to achieve. This is due in large part to the difficulty in modelling the tokamak discharge parameters, as they are highly nonlinear and time varying in nature. The difficulty of modelling the tokamak discharge parameters suggests that a control system, such as a fuzzy logic based controller, which does not require a system model may be well suited to the control of fusion plasma. In order to improve the quality of control over the plasma position within the STOR-M tokamak, the existing analog PID controller was modified. These modifications facilitate the application of a digital controller by a personal computer via the Advantech PCL-711B data acquisition card. The performance of the modified plasma position controller and an Arbitrary Signal Generator developed by the author was evaluated. This modified plasma position controller was applied successfully to the STOR-M tokamak during both normal mode and A.C. mode operation. In both cases, the modified controller provided adequate control over the position of the plasma column within the discharge chamber. Furthermore, the modified controller was more convenient to optimize than the original, existing analog PID controller. By taking advantage of the modifications that were made to the plasma position controller, a fuzzy logic controller was developed by the author. The fuzzy logic based plasma position controller was also successfully applied to the STOR-M tokamak during both normal mode and A.C. operation. The fuzzy controller was demonstrated to reliably provide a higher degree of control over the position of the plasma column within the STOR-M tokamak than the modified PID controller.

Adequate control of the position of the plasma column within the STOR-M tokamak is a chief requirement in order for experimental quality discharges to be obtained. Optimal control over tokamak discharge parameters, including the plasma position, is very difficult to achieve. This is due in large part to the difficulty in modelling the tokamak discharge parameters, as they are highly nonlinear and time varying in nature. The difficulty of modelling the tokamak discharge parameters suggests that a control system, such as a fuzzy logic based controller, which does not require a system model may be well suited to the control of fusion plasma. In order to improve the quality of control over the plasma position within the STOR-M tokamak, the existing analog PID controller was modified. These modifications facilitate the application of a digital controller by a personal computer via the Advantech PCL-711B data acquisition card. The performance of the modified plasma position controller and an Arbitrary Signal Generator developed by the author was evaluated. This modified plasma position controller was applied successfully to the STOR-M tokamak during both normal mode and A.C. mode operation. In both cases, the modified controller provided adequate control over the position of the plasma column within the discharge chamber. Furthermore, the modified controller was more convenient to optimize than the original, existing analog PID controller. By taking advantage of the modifications that were made to the plasma position controller, a fuzzy logic controller was developed by the author. The fuzzy logic based plasma position controller was also successfully applied to the STOR-M tokamak during both normal mode and A.C. operation. The fuzzy controller was demonstrated to reliably provide a higher degree of control over the position of the plasma column within the STOR-M tokamak than the modified PID controller.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 154-161). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 154-161). Also available on the Internet.

A Charge-Exchange Recombination Spectroscopy (CXRS) diagnostic has been installed on Alcator C-Mod to study the transport of light impurities in plasma. The system provides spatially (1 cm) and temporally (12.5 msec) resolved measurements of the impurity density, temperature and flow velocities of the particular impurity. Two optical arrays: poloidal (19 channels) and toroidal (10 channels), collect the light emitted from excited impurity ion populated by charge exchange process from the Diagnostic Neutral Beam (DNB) particle. The attention of this dissertation is focused on the B⁴⁺ (n = 7 [-->] 6) spectral line emitted by B⁴⁺ ion formed in the following charge exchange reaction (H⁰ + B⁵⁺ [-->] H+ + B⁴⁺*). A complex spectral model was developed to simulate emission. The high magnetic fields of C-Mod result in broad Zeeman patterns which must be taken into account for the interpretation of the line shift and broadening in terms of impurity ion velocity and temperature. After the spectral line fitting and careful identification of the charge exchange component, the calculated Doppler broadening and shifts of the spectral line profile yield information on the ion temperature and rotation. Together with the calculation of the beam density, the absolute calibration of the CXRS optical system provides us with B⁵⁺ density measurement capabilities. One of the main objectives of this work was to use the acquired impurity density, temperature and flow velocity profiles to investigate plasma transport behavior and infer the radial electric field E[subscript R] from plasma force balance equation. The focus here was placed on the region of the Internal Transport Barrier (ITB) formation 0.35 < p < 0.8. Radial electric field E[subscript R] is readily calculated in the region of the ITB foot using measured B⁵⁺ profiles. ExB velocity shearing turbulence stabilization are believed to play an important role in the physics of the ITB formation. The computed E[subscript R] profiles demonstrated the large difference between the H-mode and ITB discharges. Linear gyrokinetic stability analysis (GS2) demonstrated that shearing rate w[subscript ExB] prevails over the linear Ion Temperature Gradient (ITG) growth rates [gamma subscript max] in the region where ITB forms. / text