• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 42
  • 31
  • 22
  • 7
  • 6
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 145
  • 34
  • 18
  • 18
  • 17
  • 16
  • 10
  • 10
  • 9
  • 9
  • 8
  • 8
  • 7
  • 7
  • 7
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

La musique psychédélique britannique

Pire, Alain 24 November 2009 (has links)
La musique psychédélique britannique est née grâce à la conjonction de quatre facteurs : 1. Un contexte socio-économique et culturel extrêmement favorable. 2. La présence simultanée d'un nombre significatif de musiciens de grand talent 3. La disponibilité de drogues psychédéliques sur le territoire britannique. 4. Une série d'innovations technologiques qui ont modifié les perspectives de création sonore. Cette thèse analyse l'interaction entre ces quatre éléments et en détermine l'importance respective pour la genèse du style musical
82

Avaluació de la qualitat aromàtica, estàndard, sensorial i sanitària de poma 'Pink Lady®' durant la maduració i la frigoconservació

Villatoro Gonzàlez, Carmen 11 December 2008 (has links)
L'objectiu principal d'aquesta Tesi va ser estudiar la qualitat estàndard, aromàtica, sensorial i la seguretat abiòtica de la poma 'Pink Lady®' durant tres campanyes (2003-2004, 2004-2005 i 2005-2006), tant durant la maduració en camp com després de la frigoconservació en diferents atmosferes de conservació, períodes d'emmagatzemament i de permanència a 20 ºC. Les atmosferes controlades amb nivells de oxigen i diòxid de carboni entre 1-3% van permetre una molt bona retenció de la fermesa de la polpa, del contingut de sòlid solubles, de l'acidesa i del color de fons de l'epidermis durant la frigoconservació. Els fruits conservats sota la tecnologia de fred normal varen presentar una caiguda significativa de l'acidesa i la fermesa, sobretot en emmagatzematges llargs (25-28 setmanes) i després de 7 dies a 20 ºC. Els ésters volàtils més importants tant durant la maduració en camp com durant la frigoconservació van ser l'acetat de butil, l'hexanoat de butil, l'acetat de 2-metilbutil, l'acetat d'hexil, el propanoat d'hexil, el butanoat d'hexil, l'hexanoat d'hexil i el 2-metilbutanoat d'hexil. La màxima producció de compostos volàtils aromàtics es va aconseguir després de 13-15 setmanes de frigoconservació independentment de les condicions d'atmosfera. No obstant, el fred normal va ser la tecnologia més recomanable per a obtenir major concentració total de compostos volàtils. La biosíntesi dels compostos volàtils aromàtics al llarg de la maduració en camp i durant la frigoconservació va estar condicionada fonamentalment per la disponibilitat dels precursors dels compostos volàtils, més que per l'activitat de l'alcohol o-aciltransferasa (AAT), l'enzim responsable de forma directa amb la producció d'ésters volàtils. En relació amb l'acceptació sensorial, l'atmosfera controla amb baix oxigen (2%) i molt baix oxigen (1%) van ser les tecnologies de conservació que han proporcionat pomes amb més acceptació sensorial després de la frigoconservació. Els fruits més apreciats pels consumidors no sempre van ser els que mostraven una producció de compostos volàtils aromàtics més elevada. Per tant, es suggereix que la concentració d'alguns compostos volàtils aromàtics va ser més important que l'emissió total a l'hora de determinar l'acceptació general del fruit. Així, els compostos volàtils aromàtics que van permetre diferenciar les pomes 'Pink Lady®' més acceptades van ser el propanoat d'hexil, el hexanoat d'hexil, el 2-metilbutanoat de butil i el 2- metilbutanoat d'hexil. Cal destacar l'elevada influència de l'hexanoat d'etil i el 2-metilpropanoat de propil sobre l'acceptació sensorial per part del consumidor durant la 3ª campanya. Tots ells contribueixen de forma predominant en l'aroma de la 'Pink Lady®' aportant un aroma característic a 'poma' i 'afruitat' amb notes a 'poma verda'. La fermesa, l'acidesa i el contingut en sòlids solubles també van influir positivament en l'acceptación per part dels consumidors. Respecte a la seguretat abiòtica dels fruits, els resultats indiquen que el contingut de difenilamina, folpet i imazalil es van retenir majorment a la pell. La concentració de difenilamina a la pell dels fruits conservats en fred normal va ser menor que a les mostres conservades en les atmosferes controlades. El contingut de folpet a la pell va disminuir de forma marcada després de 13-15 setmanes de conservació més 1 dia a 20 ºC en totes les atmosferes de conservació estudiades, amb una reducció del 80%. L'imazalil va ser més persistent que el folpet durant la conservació frigorífica. Després de 13 setmanes en atmosfera controlada amb baix contingut d'oxigen més 4 setmanes en fred normal es va reduir la concentració de difenilamina als fruits conservats amb les atmosferes controlades en baix oxigen (LO) i també de folpet en els els fruits procedents d'atmosfera controlada amb molt baix oxigen (ULO). Després de 27 setmanes sota atmosfera ULO més 4 setmanes en fred normal es va reduir la concentració d'imazalil a la pell als fruits. En tots els casos, Els nivells de residus en fruit fresc sencer procedents de tractaments postcollita van respectar els límits màxims fixats per la legislació. / El objetivo principal de esta Tesis fue estudiar la calidad estándar, aromática, sensorial y seguridad abiòtica de la manzana 'Pink Lady®' durante tres campañas (2003-2004, 2004-2005 y 2005-2006), tanto durante la maduración en campo como después de la frigoconservació en diferentes atmósferas de conservación, periodos de almacenamiento y días de permanencia a 20ºC. Las atmósferas controladas con niveles de oxígeno y dióxido de carbono entre 1-3% permitieron una muy buena retención de la firmeza de la pulpa, del contenido en sólidos solubles, de la acidez y del color de fondo de la epidermis durante toda la frigoconservación. Los frutos conservados bajo la tecnologia de frío normal presentaron una caída significativa de la acidez y la firmeza sobretodo en largos periodos de almacenamiento y 7 días a 20 ºC. Los ésteres volátiles más importantes tanto durante la maduración en campo como durante la frigoconservación fueron el acetato de butilo, el hexanoato de butilo, el acetato de 2-metilbutilo, el acetato de hexilo, el propanoato de hexilo, el butanoato de hexilo, el hexanoato de hexilo y el 2-metilbutanoato de hexilo. La máxima producción de compuestos volátiles aromáticos fue después de 13-15 semanas de frigoconservación independientemente de las condiciones de atmósfera. No obstante, el frío normal fue la tecnología más recomendable para obtener mayor concentración total de compuestos volátiles. La biosíntesis de compuestos volátiles aromáticos a lo largo de la maduración en campo y durante la frigoconservación estuvo condicionada fundamentalmente por la disponibilidad de los precursores de los compuestos volátiles, más que por la actividad del alcohol o-aciltransferasa (AAT), el enzima responsable de forma directa con la producción de ésteres volátiles. En relación con la aceptación sensorial, la atmósfera controlada con bajo oxígeno (2%) y muy bajo oxígeno (1%) fueron las tecnologías de conservación que han proporcionado manzanas con más aceptación sensorial después de la frigoconservación. Los frutos más apreciados por los consumidores no siempre mostraron una producción de compuestos volátiles aromáticos más elevada. Por tanto, se sugiere que la concentración de algunos compuestos volátiles aromáticos fue más importante que la emisión total a la hora de determinar la aceptación general del fruto. De esta manera, los compuestos volátiles aromáticos que permitieron diferenciar las manzanas 'Pink Lady®' más aceptadas fueron el propanoato de hexilo, el hexanoato de hexilo, el 2-metilbutanoato de butilo y el 2-metilbutanoato de hexilo. Cabe destacar la elevada influencia del hexanoato de etilo y el 2-metilpropanoato de propilo sobre la aceptación sensorial por parte del consumidor la 3ª campaña. Todos ellos contribuyeron de forma predominante en el aroma de la 'Pink Lady®' aportando un aroma característico a 'manzana' y 'afrutado' con notas a manzana 'verde'. La firmeza, la acidez y el contenido en sólidos solubles también influyeron positivamente en la aceptación por parte de los consumidores. Respecto a la seguridad abiótica de los frutos, los resultados indican que el contenido de difenilamina, folpet y imazalil se retuvo mayormente en la piel. La concentración de difenilamina en la piel de los frutos conservats en frío normal fue menor que las muestras conservadas en átmosfera controlada. El contenido de folpet en la piel disminuyó de forma marcada después de 13-15 semanas de conservación en todas las atmósferas de conservación estudiadas, con una reducción del 80%. El imazalil fue más persistente que el folpet durante la conservación frigorífica. Después de 13 semanas en atmósfera controlada con bajo contenido más 4 semanas en frío normal redujo la concentración de difenilamina en los frutos conservados en atmósfera controlada con bajo oxígeno (LO) y también de folpet en los frutos procedentes de atmósfera controlada con muy bajo contenido de oxígeno (ULO). Después de 27 semanas bajo atmósfera ULO más 4 semanas en frío normal se redujo la concentración de imazalil en la piel de los frutos. En todos los casos, los niveles de residuos en fruto fresco entero procedentes de tratamientos postcosecha respectaron los límites máximos fijados por la legislación. / The main objective of this thesis was to study the changes in the standard quality parameters, volatile compounds emitted, consumer acceptance and abiotic safety of 'Pink Lady®' apples picked at three consecutive seasons (2003-2004, 2004-2005 and 2005-2006) during on-tree maturation and after storage under different conditions, including atmosphere composition, storage period and ripening time at 20 ºC Controlled atmospheres with oxygen and carbon dioxide levels in the range 1-3% allowed very good retention of firmness, soluble solids content, titratable acidity and background colour during cold storage. Cold storage under air led to a drop in acidity levels after long-term storage (25-28 weeks) plus 7 days at 20 ºC. The most important volatile esters in quantitative terms emitted both during on-tree maturation and after cold storage were butyl acetate, butyl hexanoate, 2-methylbutyl acetate, hexyl acetate, hexyl propanoate, hexyl butanoate, hexyl hexanoate and hexyl 2-methylbutanoate. In addition, the maximum total concentration of aroma volatile compounds was found after 13-15 weeks of cold storage irrespective of atmosphere composition; nevertheless, storage under cold air was the most advisable technology to obtain the maximum production of total aroma compounds. The biosynthesis of aroma volatile compounds both during on-tree maturation and after cold storage was conditioned by the availability of the necessary precursors rather than by the activity of alcohol o-acyltransferase (AAT), the direct enzyme responsible for the production of volatile esters. In connection with consumer's acceptance, CA storage appeared as highly advisable in order to get the best sensory quality of 'Pink Lady®' apples after cold storage. The best accepted fruit did not always show the highest production of aroma volatile compounds, suggesting that the concentration of some specific volatile compounds is more important than total aroma volatile emission in determining overall fruit acceptability. Some specific aroma volatile compounds, namely hexyl propanoate, hexyl hexanoate, butyl 2-methylbutanoate, hexyl 2-methyllbutanoate, ethyl hexanoate and propyl 2-methylpropanoate (only during the last experimental season), accounted for the differentiation between well-accepted and only marginally accepted samples. These compounds contributed to the aroma profile of 'Pink Lady®' apples by conferring a characteristic aroma of 'apple' and 'fresh-green fruity'. Firmness, titratable acidity and soluble solids content were found to have a positive influence on acceptability. Regarding abiotic safety of 'Pink Lady®' apples following treatments with different agrochemicals, results indicate that diphenylamine, folpet and imazalil were retained mainly in the skin. Diphenylamine concentration in the skin of air-stored fruit was smaller than that of CAstored samples. Folpet concentration in the skin diminished after 13-15 weeks of cold storage plus 1 day at 20 ºC in all the atmosphere conditions studied, with a reduction of 80%. Imazalil was more persistent during storage than folpet. After 13 weeks in controlled atmosphere with low oxygen plus 4 weeks in normal air, diphenylamine and folpet contents in skin were reduced in low oxygen (LO) and ultra low oxygen (ULO) stored samples. Imazalil content in the skin of fruit was reduced after 27 weeks in ULO plus 4 weeks in normal air. In all cases, residue levels in the whole fresh fruit were lower than the maximum residue limits established by the Spanish legislation.
83

"Cause-Related Marketing, Win-Win-Win?" : A Qualitative Study of the Pink Ribbon in Swedish Partner Companies´ CRM Campaign

Stark, Caroline, Berggren, Jonas January 2010 (has links)
No description available.
84

A rhetorical analysis of Pink Floyd's The wall

Limeberry, John January 1989 (has links)
Through an examination of the album The Wall by the group Pink Floyd, the intention of this study was to answer questions such as tale following in hopes that a clearer understanding of The Walls popularity might be obtained. What are the major and minor events in this musical narrative? Who are the main characters in -111ne narrative? What cause-and-effect relationships are established in the narrative? now did The Wall function rhetorically in achieving a sense of identification with contemporary listeners?The study found that The Wall achieved identification through the use of its themes which centered around war, derisive school systems, parental overprotection. collapse, and extreme alienation.The study notes that The Wall contained substantial social commentary, and states that the rock music form, often belittled as nothing more than hedonistic escapism, is capable of producing work worthy of scholarly examination. / Department of Speech Communication
85

The Gamer Girls of Jorvik : Motivations of Play in Star Stable Online

Hiidenheimo, Karoliina, Andersson-Junkka, Ida January 2018 (has links)
This thesis examines the motives of play amongst girl gamers aged nine to seventeen. It focuses on the players of the game Star Stable Online also referred to as a ‘pink’ game. It is an empirical study, using a mixed method design. The study is split into two parts and the results from part two were used to support the results from part one. In the first part of the study, quantitative data was collected through an online survey using a closed card sorting method. The survey was complemented with open and closed questions, which also gave the form a qualitative element. The second part of the study was purely qualitative, consisting of an artwork study where the method resembles arts-based elicitation. The girls were requested to send in artwork depicting the thing they love the most in the game or something they would love to have. The images were then put through thematic analysis and the outcome was compared with the data collected in the survey. The results showed that girls chose to play Star Stable Online due to their interest in horses as well as to immerse themselves in its story and narrative.
86

Caracterização nutricional e funcional da proteína recuperada de cefalotórax de camarão-rosa e estudo do aproveotamento do produto residual / Nutritional and functional characterization of the protein recovered from pink-shrimp cephalotorax and study of the residual product

Alfredo Tenuta Filho 21 December 1983 (has links)
Foi desenvolvido um método de recuperação de proteína de cefalotórax de camarão-rosa (Penaeus brasiliensis e Penaeus paulensis), tendo como base a separação física e a insolubilização por precipitação isoelétrica (pH 4,5) e aquecimento (70-75°C/5min), caracterizando-se posteriormente o produto obtido e o resíduo sólido resultante. O método empregado propiciou um rendimento de cerca de 2% e a proteína recuperada mostrou-se acompanhada de reduzida quantidade de cálcio (0,03%) e quitina (0,5%) e de níveis de metais tóxicos (Hg, Cd, Pb, Cu e Zn) muito abaixo de limites permitidos em alimentos. Com base no cômputo químico dos amino ácidos essenciais, a proteína obtida apresentou uma qualidade nutricional de 54% e de 90%, em relação à caseína e à proteína da F.A.O/O.M.S, respectivamente, limitada primariamente pelo triptofano. A eficiência desta proteína em promover o crescimento dos animais foi de 81%, comparada à caseína, prejudicada parcialmente por sua digestibilidade (78%). A solubilidade da proteína estudada foi baixa a pH 7 (8,70%) e pôde ser melhorada (20 a 97,5%) através de tratamento alcalino e/ou eliminação do aquecimento na recuperação da mesma. Sua capacidade de emulsificação foi de 31% a 125% comparada à da proteína de soja comercial (Proteimax 90 HG), quando adotou-se também o tratamento alcalino e/ou a eliminação do aquecimento na sua recuperação. Com base no cômputo químico dos amino ácidos essenciais, a qualidade nutricional da proteína do residuo foi de 21% e de 35%, respectivamente em relação à caseína e à proteína da F.A.O/0.M.S., com limitação primária em triptofano. O rendimento em quitina e em quitosana atingiu 2,7g e 2,5g a partir do resíduo equivalente a 100g de cefalotórax ou 29g e 26g para cada 100g do mesmo, respectivamente. / A method for the protein recuperation from pink shrimp (Penaeus brasilensis and Penaeus palensis) cephalotorax was developed and the recuperated product and generated solid waste were characterized. The physical separation and protein insolubilization by isoelectric precipitation (pH4,5) and heating (70-75°C/5min) were the base of this method. The method promoted a yie1d of 2% and the protein product showed low quantities of calcium (0,03%) and chitin (0,5%) and very low quantities of toxic metals (Hg, Cd, Pb, Cu and Zn) in relation to limits permited in foods. Based on the essential amino acids chemical score the recuperated protein showed a nutritional quality of 54% and 90%, compared to casein and F.A.O/O.M.S reference protein, respectively, primarily limited in triptophan. The eficiency of this protein in animal growth promotion was of 81% in relation to casein, limited partially by its digestibility (78%). The solubilty of the protein was low at pH 7 (8,70%) and was improved (20 to 97,5%) through the alkaline treatment and/or heating elimination in its recuperation. The emulsification capacity of this protein was from 31% to 125% campared to commercial say protein (Proteimax 90 HG) when the a1ka1ine treatment and/or heating elimination was also used. Accarding to the essential amino acids chemical score the protein nutritional quality of the solid waste was of 21% and 35% respectively, in relation to casein and F.A.O/O.M.S. reference proteint with primary limitation in triptophan. The yield in chitin and chitosan was 2,7g and 2,5g/100g cephalotorax or 29g and 26g/100g solid waste, respectively.
87

Analise histologica de dentes deciduos rosados apos a morte

Souza, Andreia Cristina Breda de 17 September 2002 (has links)
Orientador: Eduardo Hebling / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-02T16:23:19Z (GMT). No. of bitstreams: 1 Souza_AndreiaCristinaBredade_M.pdf: 2592570 bytes, checksum: 3e2aefee4ccf5baaad436d20f9d7fa81 (MD5) Previous issue date: 2002 / Resumo: A pigmentação rosada é uma alteração cromática dos dentes, que pode estar relacionada a mortes súbitas e violentas, resultante do extravasamento sanguineo a partir da polpa dentária, com penetração da hemoglobina ou seus subprodutos no interior dos túbulos dentinários. Fatores como a umidade, temperatura e a posição em que são encontrados os corpos são considerados como coadjuvantes no desenvolvimento do fenômeno. Neste trabalho foram utilizadas duas amostras com o objetivo de analisar as fases de formação desta alteração cromática, sendo uma amostra constituída de dentes decíduos naturalmente rosados e a outra de dentes decíduos cuja pigmentação rosada foi reproduzida experimentalmente. Após a indução da pigmentação rosada, através da injeção sanguínea a partir do ápice radicular, quando da observação da modificação cromática os elementos dentários foram submetidos em diferentes dias a uma análise histológica e outra espectrofotométrica. Os resultados obtidos através das duas análises permitiram-nos concluir que a hemoglobina íntegra é a responsável pela alteração de cor, os seus subprodutos não têm papel fundamental no desenvolvimento do fenômeno e que a sua degradação não acontece de forma única e é mais lenta do que previamente se pensava / Abstract: Pink pigmentation is a chromatic change of teeth that may be related to sudden and violent deaths. It is caused by blood flow out trom dental pulp, with the penetration of hemoglobin and its sub products into dentinal tubules. Factors such as temperature and the position of the bodies are considered to help the development of such situation. This research used two samples to analyze the phases of that chromatic change. One of the samples was a group of naturally pink deciduous teeth. The other group was deciduous teeth that the pink pigmentation was reproduced experimentally. After reproduction of pink pigmentation, these teeth were histological and spectrophotometric analyzed in different days. Therefore it was concluded that the hemoglobin is responsible for color change and its degradation happens slower that was earlier thought / Mestrado / Mestre em Odontologia Legal e Deontologia
88

Trophic niche and foodweb dynamics within and among juvenile salmon species in years of contrasting ocean conditions

Jenkins, Erica 26 September 2011 (has links)
The ecological niche of a population is dynamic and will be affected by changes in the ecosystem and as a population migrates. An ontogenetic niche shift can also occur as organisms grow and can include changes in morphology, habitat, and feeding behaviour. Although they are the two most abundant salmon species, and are further augmented through hatchery stocking, it is unclear the degree to which the niches of juvenile pink salmon (Oncorhynchus gorbuscha) and chum salmon (O. keta) overlap. Furthermore, juvenile pink salmon and chum salmon undergo a period of rapid growth during their first summer at sea and it is unclear how their ecological niche changes with their ontogeny. Understanding the foodweb dynamics of juvenile salmon in the coastal marine environment is important because a large proportion of the overall mortality of salmon is thought to occur during their first summer at sea. The purpose of this study is to determine the degree to which the niches of juvenile pink salmon and chum salmon overlap, how their trophic position and food source changes as they grow into a new ontogenetic niche, and how these processes are affected by ocean conditions. I expected that years of poorer feeding conditions and increased competition would result in reduced trophic position and greater overlap of the niches of juvenile pink salmon and chum salmon. I hypothesized that juvenile salmon would shift their diet to a more offshore-based foodweb as they grew and that their trophic position would increase with size, but that the shift would be stronger when feeding conditions were improved. Statistical analysis showed evidence that the overlap of the niches of pink salmon and chum salmon increased when the abundance of salmon was high. Contrary to expectations, the trophic position of salmon appeared to decrease under favourable conditions. The trophic position of both pink salmon and chum salmon was higher in the southern portion of the study area, and increased when juvenile abundance was high. I suggest that the higher trophic position among juvenile salmon when there is more competition might result from increased reliance on gelatinous zooplankton, which are carnivorous, but a nutritionally poor food choice compared to other common prey items. The ontogenetic shift from summer to fall among juvenile salmon included a shift to a more offshore-based diet and a higher trophic position. In the northern portion of the study area, which was comprised of the southern reaches of the Alaska Coastal Current (ACC), the shift to an offshore-based food source was more pronounced than the trophic shift. In the southern portion of the study area, which included the Transition Domain (TD) between the ACC and the California Current System (CCS), the shift to a higher trophic position was more pronounced than the shift in food source. The results of this study suggest that if climate change leads to poorer feeding conditions, the niches of pink salmon and chum salmon may increasingly overlap when the abundance of these species is high. Hatchery stocking of these species may also contribute to this trend if it leads to a greater abundance of juvenile salmon in the coastal marine environment. There is evidence that the structure of the food web and the nature of the ontogenetic niche shift are very different in the ACC and the TD, and climate change and hatchery stocking will most likely affect these regions differently. / Graduate
89

Geochemical Comparison of Ancient and Modern Eolian Dune Foresets Using Principal Components Analysis

Little, David A. 01 November 2016 (has links)
Geochemistry has been used to determine the provenance and diagenetic history of eolian sandstone deposits. However, the grain size, sorting, cementation, and detrital composition of eolian units can change along dune foreset laminae. The purpose of this study was to test for consistent trends of compositional change along dune foresets. Such trends could increase the quality of geochemical sampling of eolian sandstones and possibly aid in estimating the original height of ancient sand dunes. XRF data was gathered for both major and trace elements from the Pennsylvanian to Permian Weber Sandstone, Early Jurassic Navajo Sandstone, and modern Coral Pink Sand Dunes of southern Utah. Data was plotted using both 2-dimensional scatter plots and 3-dimensional principal components analysis (PCA) plots. The PCA plots proved to be the most informative and suggest that there are no consistent, statistically significant geochemical trends within or between the three units sampled. However, this study found that PCA was able to show significant geochemical differences between the three units sampled, even when they are all dominated by a single mineral (>90% quartz). The Weber Sandstone had the most varied composition, and dunes within the unit could be highly dissimilar to each other. The Navajo Sandstone had less overall geochemical variability than the Weber Sandstone, and individual dunes were similar to each other. The modern Coral Pink Sand Dunes had much less compositional variation than either of the other two units, and dunes in this unit were very similar to each other.
90

Diagnostika dohasínajícího dusíkového plazmatu metodou optické emisní spektroskopie / Diagnostic of nitrogen post-discharge by optical emission spectroscopy

Kabeláčová, Kateřina January 2018 (has links)
The aim of this thesis is diagnose post-discharge nitrogen plasma with optical emission spectroscopy. There is long interest of investigated of nitrogen post-discharge plasma and study how to use it in theory as well as in practice. All results were measured with method of optical emission spectroscopy of post-discharge plasma. Discharge was generated by direct-current voltage generator with flowing regime. In this thesis was used for different series of experiments. First experiment was performed with adding water vapour into argon plasma. Measuring was processed at constant current 140 mA, voltage 1.5 V and pressure 1 000 Pa. It was changed flow rate and for each individual flow rate was measured in range 1–25 cm from end of active discharge. Second experiment was with adding nitrogen into argon plasma. Measuring was processed at constant current 140 mA, voltage 1.5 V and pressure 1 000 Pa. We were changing flow rate of nitrogen (0,2 sccm, 0,4 sccm and 0,8 sccm). For each individual flow rate was same experiment with changing distance from active discharge. Third experiment was about adding mercury vapour into nitrogen post-discharge. Measuring was processed at constant current 120 mA, voltage 3.5 V and pressure 1 000 Pa. Measuring was performed with two configuration: with diaphragm and without it. Last experiment was about adding air into argon plasma. Measuring was processed at constant current 140 mA, voltage 1.0 V and pressure 1 000 Pa. Temperature of outer face of tube was measured by thermocouple and infrared thermometer, was measured for last two experiments (argon – air and nitrogen). During experiments with pure nitrogen was visible phenomenon called pink afterglow which is manifested by noticeable increase pink coloration. Optical emission spectrums post-discharge was take at various range of wavelength. At argon with water vapour was 280–600 nm and at adding nitrogen into argon was at range 320–500 nm. At added mercury vapour into nitrogen was 320–600 nm. For experiment argon – air was wavelength range 320–600 nm. From results of experiments were designed dependencies of calculated intensity from measured spectra on distance from active discharge. Also were constructed dependencies of measured temperature on distance from active discharge.

Page generated in 0.0511 seconds