To see the other types of publications on this topic, follow the link: Polar parameters.
Dissertations / Theses on the topic 'Polar parameters'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 25 dissertations / theses for your research on the topic 'Polar parameters.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Saha, Ujjwal. "Dielectric relaxation parameters of polar liquids from ultra-high frequency conductivity of solutes in non-polar solvents." Thesis, University of North Bengal, 1993. http://hdl.handle.net/123456789/660.
Full text
2
Ramsch, Roland. "Catanionic surfactants in polar cohesive solvents : impact of solvent physical parameters on their aggregation behavior." Toulouse 3, 2010. http://thesesups.ups-tlse.fr/1005/.
Full textAbstract:
On trouve peu d'études, dans la littérature, sur les tensioactifs (TA) catanioniques - formés d'une paire d'ions entre un TA anionique et un TA cationique - en milieu nonaqueux. Nous avons voulu rationaliser, dans ce travail, le comportement d'agr´egation de ce type de tensioactifs en les étudiant comparativement dans l'eau, dans le formamide, dans le glycérol et dans des mélanges de ces solvants polaires et cohésifs. Nous avons pour ce faire synthétis´e trois différents types de TA catanioniques (alcanoate d'alkylammonium, tétradécanoate de norbornène méthylène ammonium, alcanoate de N-alkylammonium-1-d´eoxy-D-glucitol). Les TA catanioniques ont la propriété de s'agréger en vésicules dans l'eau. Dans le cas des autres solvants ou mélanges des solvants, nous avons constat que le type d'agrégat que forment les TA catanioniques dépend de deux principaux facteurs : la constante diélectrique du solvant et le degré d'interaction entre les deux TA. En effet, le formamide ayant une constante diélectrique plus élevée que l'eau, il exerce une force dissociative sur la paire d'ions qui peut ainsi être séparée pour conduire `a un mélange de TA ioniques monocaténaires formant alors des micelles. D'autre part, une augmentation de l'effet hydrophobe, obtenu en utilisant des chaînes hydrophobes plus longues, renforce la paire d'ions et conduit `a la formation de vésicules dans le formamide pur. Par ailleurs, l'étude du système tétradécanoate de norbornène méthylène ammonium a également montré l'importance des interactions hydrophobes entre les têtes polaires, un autre facteur pouvant favoriser la formation de vésicules dans le formamide pur<br>In the literature, little work has been done on catanionic surfactants in non-aqueous solution. Catanionic surfactants are ion pairs composed of an anionic and a cationic surfactant. In the frame of this work, we wanted to rationalize the aggregation behavior of this surfactant type by studying them in water, in formamide, in glycerol and in some mixtures of these polar and cohesive solvents. For this issue, we synthesized three different types of catanionic surfactants (alkylammonium alkanoate, norbornene methyleneammonium tetradecanoate, N-alkylammonium-1-deoxy-D-glucitol alkanoate). Catanionic surfactants usually form vesicles in water. In the case of non-aqueous solvents and mixtures of solvents, we could observe that the type of aggregates formed with catanionic surfactants depends on two major factors: the dielectric constant of the solvent and the degree of interaction between the two surfactants. Effectively, formamide having a higher dielectric constant than water exerts a dissociative force on the ion pair. The ion pair can be separated leading to a mixture of monocatenar ionic surfactants, which then forms micelles. On the other hand, hydrophobic effects can be increased using longer hydrophobic chains, which reinforce the ion pair and lead to the formation of vesicles in pure formamide. Moreover, the study on the norbornene methyleneammonium tetradecanoate showed the importance of hydrophobic headgroup-headgroup interactions, an additional parameter which can favor vesicle formation in pure formamide
3
Ormbostad, Ingunn. "Relationships Between Persistent Organic Pollutants (POPs) and Plasma Clinical-Chemical Parameters in Polar Bears (Ursus maritimus) from Svalbard, Norway." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16823.
Full textAbstract:
In the present study, clinical-chemical parameters in relationship to persistent organic pollutants (POPs) were investigated in plasma samples from polar bears (Ursus maritimus) captured at Svalbard in 2007. The clinical-chemical parameters examined were: hematocrit (HCT), hemoglobin (HB), aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), &#947;-glutamyltransferase (GGT), creatine kinase (CK), triglycerides (TG), cholesterol (CHOL), high-density lipoprotein (HDLP), creatinine (CREA), urea, and potassium (K). Altered homeostasis of clinical-chemical parameters in plasma may indicate impact on liver, kidney, heart, muscle, bone, metabolism or the endocrine system. Of the twelve clinical-chemical parameters examined in this study, significant association to POPs were found in seven parameters in female polar bears, whereas eight parameters were found in male polar bears. The results indicate that different POPs may exhibit toxic effect to different organs of polar bears. Liver toxicity was indicated by a decrease of hematologic parameters (HCT and HB), a decrease of liver enzymes (ASAT and GGT), and an elevation of metabolites (TG, CHOL, and HDLP) in relation to contaminant concentrations. Further, kidney toxicity was indicated by a decrease of CREA concentrations in relation to contaminant-concentrations, and muscle toxicity by a decrease in CK concentrations in relation to contaminant-concentrations. Continuous exposure to contaminants may therefore result in decreased renal, hepatic, and muscular functions. It is possible that these POP-associated effects may reduce the fitness and survival of polar bears. The results also indicate that clinical-chemical parameters in plasma can be applied as a non-invasive biomarker for toxicity to organs and metabolic homeostasis caused by exposure to POPs in polar bear. Because of the fast response to environmental factors, including POPs, these biomarkers can be used to measure an effect at an early stage, as well as at low exposure concentrations. However, the present study was not designed to evaluate the relationship between cause and effect, and it is important to take into consideration other factors that can affect clinical-chemical parameters when interpreting the results.
4
Chase, Adam Thomas. "Flight Testing Small UAVs for Aerodynamic Parameter Estimation." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1191.
Full textAbstract:
A flight data acquisition system was developed to aid unmanned vehicle designers in verifying the vehicle's design performance. The system is reconfigurable and allows the designer to choose the correct combination of complexity, risk, and cost for a given flight test. The designer can also reconfigure the system to meet packaging and integration requirements. System functionality, repeatbility, and accuracy was validated by collecting data during multiple flights of a radio-controlled aircraft. Future work includes sensor fusion, thrust prediction methods, stability and control derivative estimation, and growing Cal Poly's small-scale component aerodynamic database.
5
Fendri, Ahmed. "Impedimetric Sensor System for Edible Oil Quality Assessment." Universitätsverlag Chemnitz, 2019. https://monarch.qucosa.de/id/qucosa%3A37173.
Full textAbstract:
The repeated usage of frying oil is hazardous due to the degradation caused by chemical reactions, which happen while heating. The total polar compounds and the free fatty acids are the main two chemical parameters affected by frying. These parameters increase significantly with the use of oil for frying and are reported as reasons for causing serious illnesses like heart diseases.
For this purpose, sensor systems for oil quality assessment are necessary. In fact, changes of the composition due to frying leads to variation of its dielectric parameters. This can be measured using a capacitive sensor and the measurement of its impedance change. The main challenge thereby is that the impedance changes are very small and stray capacitances have a big influence on the measurements.
In this context, this work proposes a sensor system with high accuracy able to detect the small changes that occur in the resistance and capacitance under influence of stry capacitances. Theoretical and simulation studies are carried out for different cap acitive sensors as well as meas urement procedures of its cornp lex imp edance.
The sensor should provide a high sensitivity to relative perrnittivity and the electrical conductiv ity, and at the same time a small size and a high reproducibility. Interdigital electrodes sensor with a suitable design fulfils all these requirements.
A deep consideration of stray capacitances is needed to realize an accurate sensor system. For t hese reasons, the design of the measurement circuit is crucial within this work. We propose, a measurernent circuit based on a combinat ion of the method of capacitance to voltage conversion and the phase shift measurement method. By cornbining both rnethods together it is possible to rneasure accurate ly the complex irnpedance of edible oil. Experimental results show that measurement systern is capable to detect small changes of dielectric parameters, which are correlated to the chemical parameters.<br>Die mehrfach wiederholte Verwendung von Frittieröl ist aufgrund der Qualitätsver schlechterung, die während des Erhitzens auftreten durch chemische Reaktionen verursacht wird, gefährlich für die Gesundheit. Die totale polaren Kompon enten und die freien Fettsäuren sind die zwei wichtigsten chemischen Komponenten, die wesentlich durch das Braten beeinflusst werden. Diese Komponenten erhöhen sich signifikant mit der Wiederverwendung von Bratöl und verursachen u. a. ernste Herzkrankheiten.
Diese Arbeit zielt darauf hin, ein mobiles, kostengünstiges, einfach zu verwenden des Sensorsystem für die Abschätzung der Ölqualität zu entwickeln. Das System charakterisiert die Veränderung der elektrischen Parameter des Öls durch Messung der Änderung seiner komplexen elektrischen Eigenschaft en.
In dieser Arbeit wurde ein Sensorelement mit interdigitalen Elektroden entwickelt, der eine hohe Empfindlichkeit auf die relative Permittivität und die elektrischen Leitfähigkeit des Öls hat und dabei einer hohe Reproduzierbarkeit erzielen kann.
Es wird ein Messverfahren vorgeschlagen, das auf der Wandlung in einer Spannung und einer Phasenverschiebung basiert. Sowohl durch theoretische Überlegungen als auch durch Simulationen konnte belegt werden, dass die Kombination beider Metho den eine akkurate Messung der Komplexem Imped anz hochdielektrischer Materia lien ermöglichen kann. Experiment elle Ergebnisse zeige n, dass das Messsystem in der Lage ist , kleine Änderungen der dielektrischen Parameter zu erfassen, die mit den chemischen Ölparamtern stark korrelieren.
6
McGaughran, Angela. "Polar eveolution: molecular genetic and physiological parameters of Antarctic arthropod populations : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Molecular Biosciences at the Allan Wilson Centre of Molecular Ecology and Evolution, Institute of Molecular Biosciences, Massey University, Palmerston North, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1163.
Full textAbstract:
This thesis is presented as a collection of research papers synthesising knowledge gained during the period of candidacy. Its underlying focus is the examination of evolution from a variety of perspectives for terrestrial arthropods (springtails) in an Antarctic setting. These perspectives include investigation of the ways in which springtail populations respond both physiologically and genetically to environmental variability over historical and contemporary time-scales. While the physiological and genetic may seem two worlds apart, this thesis recognises that, in reality the two are inextricably linked. Thus, when genetic differentiation between populations of the same species can be demonstrated, physiological differentiation of these populations may also be predicted (and vice versa). Therefore, across several locations and springtail species, physiological and genetic parameters of individuals and populations are examined both separately and, where possible, in concert. The physiological aspect of this thesis focuses on the springtail Gomphiocephalus hodgsoni from continental Antarctica. In addition to providing the first metabolic rate data for a continental Antarctic springtail, seasonal variation in metabolic rates is examined across multiple temporal and spatial scales to evaluate the ways in which individuals and populations respond to environmental variability. Metabolic activity in this species is intricately linked to a variety of factors, both intrinsic and extrinsic. These include biological function, temperature profiles in the local microclimate, and body mass and genetic differences among populations. In the genetically-focused aspect of this thesis, population genetic patterns of G. hodgsoni from several continental locations and Cryptopygus antarcticus antarcticus from locations across the Antarctica Peninsula are compared. Here, the importance of differing evolutionary histories in influencing patterns of contemporary genetic population structure is highlighted. While both species have been similarly affected genetically by Pleistocene (2 Ma – present) glacial cycling, it is clear that differences in timing of colonisation events and subsequent population expansions have left distinct genetic signatures in each species. In a separate molecular study, phylogenetic analyses are employed to study members of the circum-Antarctic springtail family Isotomidae. Thesis Abstract The genetic ancestry among these closely related species is shown to reflect a diverse evolutionary origin in the Miocene (23 – 5 Ma), subsequent to which both vicariant and dispersal processes have been important. Phylogenetic re-constructions tease out the relationships among sister species, and the identification of several genetically distant lineages suggests that a revision of current species designations is required. Finally, two studies that integrate the physiological and molecular genetic are presented. First, metabolic rate variation across several locations on sub-Antarctic Marion Island in the springtail Cryptopygus antarcticus travei is examined. This variation is related to the genetic structure of populations to show that historical and contemporary environmental characteristics have left their trace in the expression of both genetic and physiological variability of these populations. Second, the perceived association between metabolic rate and genetic (mutation) rate is investigated more closely - a sophisticated Bayesian correlation analysis detects that there is an indirect relationship between metabolic rate and underlying species phylogeny in C. a. travei. Thus, the physiological and molecular genetic elements of this thesis test or advance important hypotheses within their own fields, and the integrated approach applied is a new step in interpreting evidence of physiological adaptation in Antarctic species. In its multi-faceted approach to evolutionary studies, this thesis enhances understanding of the current picture of springtail evolution in polar environments.
7
Molčan, Vladimír. "Určení prostorových vztahů jeřábové dráhy." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-227104.
Full textAbstract:
The main theme of this master thesis is the design of technological process measurement and processing of measured data entered crane tracks to determine the geometric parameters of these crane tracks. Diploma thesis further describes the procedure for testing and possible rectification surveying equipment and instrumentation. The thesis is divided of 7 parts, contains 31 images, 4 graphs, 44 tables and 13 attachments. The theoretical part of this thesis contains information about several types of cranes, methods of measurement and processing, as well information on legal and technical regulations related to this topic of the thesis. The fourth and fifth parts of this thesis provides information on selected crane tracks on which the measurements were taken, the choice of methods of measurement, processing technique and the results obtained. The final part of the thesis includes evaluation of the results obtained, comparing methods of measurement, processing, evaluation and design of a technique of determining the geometric parameters of crane tracks.
8
Bernardi, Camila Motta Marin. "Desempenho de progênies e clones de Eucalyptus grandis hill ex. Maiden em sistema silvipastoril." Ilha Solteira, 2018. http://hdl.handle.net/11449/154363.
Full textAbstract:
Orientador: Miguel Luiz Menezes Freitas<br>Resumo: Neste estudo objetivou-se estimar parâmetros genéticos e estatísticos para caracteres quantitativos nos primeiros seis anos de crescimento de progênies de Eucalyptus grandis em sistema silvipastoril; comparar a produtividade, estabilidade e adaptabilidade das progênies em diferentes idades e mensurar a produção de forragem e as características morfológicas e bromatológicas do capim Urochloa decumbens cv. Basilisk em crescimento livre no sub-bosque das árvores. Foram mensurados a altura (ALT), diâmetro a altura do peito (DAP) e sobrevivência (SOB), aos 2, 3, 4, 5, e 6 anos após o plantio. O delineamento utilizado foi o de blocos casualizados desbalanceados com 150 tratamentos (147 progênies de Eucalyptus grandis e três clones comerciais: C041H, P4295H e H15), 26 repetições e uma planta por parcela, no espaçamento de 2,0 x 2,5 x 4,0 m. Para avaliação do capim foram coletadas amostras da área abaixo e entre as linhas duplas de E. grandis. Na análise individual, os clones comerciais tiveram praticamente 100% de seus indivíduos entre os primeiros 250 classificados, as progênies 25 e 162 apresentaram número significativo de indivíduos nesta classificação. Em relação a classificação dos genitores, ao longo dos anos, os clones C041H e H15 sempre ficaram entre as primeiras posições. Mas as progênies 25 e 162 superaram o clone P4295H nos caracteres ALT, DAP e VOL, com correlação alta e positiva entre os anos para ALT e DAP (>0,74). Houve diferença significativa entre os tratamentos no ... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: The objective of this study was to estimate genetic and statistical parameters for quantitative traits in the first six years of growth of Eucalyptus grandis progenies in the silvipastoril system; to compare productivity, stability and adaptability of progenies at different ages and to measure forage production and morphological and bromatological characteristics of Urochloa decumbens cv. Basilisk in free growth in the understorey of the trees. Height (ALT), diameter at breast height (DAP) and survival (SOB) were measured at 2, 3, 4, 5, and 6 years after planting. The experimental design was a randomized block with 150 treatments (147 progenies of Eucalyptus grandis and three commercial clones: C041H , P4295H and H15), 26 replicates and one plant per plot, at a spacing of 2.0 x 2.5 x 4 , 0 m. For evaluation of the grass samples were collected from the area below and between the double lines of E. grandis. In the individual analysis, commercial clones had practically 100% of their individuals among the first 250 classified, progenies 25 and 162 presented a significant number of individuals in this classification. Regarding the classification of the parents, over the years, the clones C041H and H15 always were among the first positions. But progenies 25 and 162 outperformed clone P4295H in ALT, DAP and VOL, with high and positive correlation between the years for ALT and DAP (> 0.74). There was a significant difference between the treatments during the evaluation years for the ... (Complete abstract click electronic access below)<br>Doutor
9
Zaruma, Darlin Ulises Gonzalez. "Pomar de sementes por mudas em Eucalyptus camaldulensis e Hymenaea stigonocarpa : uma opção para o melhoramento e a conservação genética em espécies arbóreas exóticas e nativas /." Botucatu, 2020. http://hdl.handle.net/11449/192613.
Full textAbstract:
Orientador: Mario Luiz Teixeira de Moraes<br>Resumo: As espécies florestais possuem grande importância econômica, pois oferecem diversos produtos fundamentais para a sociedade, mas dada a impossibilidade de se separar ações de melhoramento das de conservação de recursos genéticos, técnicas como os testes combinados de progênies e procedências, tanto para espécies exóticas ou nativas, visam a seleção de árvores pelo valor genético e a transformação dos experimentos em PSM (pomares de semente por mudas). Os pomares de sementes são os vetores de produção de sementes de alta qualidade genética, que ligam as atividades de melhoramento das árvores às práticas de conservação. No anterior contexto, sementes de polinização aberta provenientes de uma população base de Eucalyptus camaldulensis e de um fragmento de Cerrado com Hymenaea stigonocarpa, foram coletadas e plantadas na Faculdade de Engenharia de Ilha Solteira (FEIS/UNESP), em Selvíria-MS. O objetivo deste trabalho foi verificar a variação genética e ganhos genéticos a partir do desbaste dentro de progênies de E. camaldulensis aos 10 anos de idade e estimar parâmetros genéticos populacionais, por meio de marcadores moleculares do tipo microssatélites para H. stigonocarpa, com vistas ao melhoramento genético e conservação, respectivamente. Para análise quantitativa, os caracteres altura (ALT), diâmetro a altura do peito (DAP), volume (VOL), densidade básica (DBM) e sobrevivência (SOB) foram utilizados. Assim os valores observados para sobrevivência (>90%) de E. camaldulensis indic... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: Forest species are of great economic importance, as they offer several fundamental products for society, but given the impossibility of separating actions to improve those from the conservation of genetic resources, techniques such as the combined testing of progenies and provenances for both exotic and native species, aim at the selection of trees by their genetic value and the transformation of the experiments in PSM (seed orchards by seedlings). Seed orchards are the vectors of seed production of high genetic quality, which link tree improvement activities to conservation practices. In the previous context, open pollination seeds from a base population of Eucalyptus camaldulensis and a fragment of Cerrado with Hymenaea stigonocarpa, were collected and planted at the Faculty of Engineering of Ilha Solteira (FEIS/UNESP), in Selvíria-MS. The objective of this work was to evaluate the genetic variation and genetic gains from thinning within E. camaldulensis progeny at 10 years of age, and to estimate population genetic parameters, using microsatellite molecular markers for H. stigonocarpa, with a view to genetic improvement and conservation, respectively. For quantitative analysis, the characters height (H), diameter at breast height (DBH), volume (VOL), basic density (DBM) and survival (SUR) were used, thus the values observed for survival (> 90%) indicate good adaptation of the species to the place. Estimates considered to be of high magnitude were obtained for the coefficie... (Complete abstract click electronic access below)<br>Doutor
10
Mirjana, Topić. "Fiziološki aspekti otpornosti hrasta lužnjaka (Quercus robur L.), cera (Quercus cerris L.) i crne topole (Populus nigra L.) u uslovima vodnog deficita." Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2015. https://www.cris.uns.ac.rs/record.jsf?recordId=95391&source=NDLTD&language=en.
Full textAbstract:
U radu je ispitan uticaj vodnog deficita na fiziološke osobine klonova crne topole ipopulacija hrasta lužnjaka i cera, kao i mogućnost oporavka ovih biljaka nakon ponovnog uspostavljanja optimalnog vodnog režima. Cilj istraživanja je bio da se ukaže na potencijal ispitivanih genotipova topole i hrastova za opstanak u promenljivim uslovima životne sredine, u skladu sa aktuelnim klimatskim promenama koje uključuju smanjenje količine padavina i ograničenu dostupnost vode. Dobijeni rezultati su pokazali specifično variranje ispitivanih morfo-anatomskih, fizioloških i biohemijskih parametara koje je zavisilo od momentalne vlažnosti zemljišta na primenjenom tretmanu (kontrola, suša praćena oporavkom, konstantna suša) i od genotipa biljke. Negativan uticaj vodnog deficita na tretmanu konstantne suše je u najmanjoj meri bio ispoljen na rastenje klona topole X/32, populaciju hrasta lužnjaka L1 i populaciju hrasta cera C1. Indeks tolerancije na stres izračunat na osnovu visine biljke (PHSI) takodje je potvrdio dobru morfološku prilagodjenost pomenutih genotipovana uslove suše. Dobijene vrednosti indeksa stoma ukazuju da vodni status ispitivanih populacija hrastova nije bio naroĉito pogodjen vodnim deficitom na sušnim tretmanima. Tretman konstantne suše je u oba ogleda doveo do najvećeg smanjenja vrednostiparametara razmene gasova kod skoro svih genotipova. S druge strane, primenjeni sušni tretmani nisu uslovili smanjenje sadržaja fotosintetiĉkih pigmenata, kao ni parametra Fv/Fm, kod većine ispitivanih biljaka. U odnosu na kontrolu, sadržaj prolina u listovima ispitivanih biljaka na tretmanu konstantne suše bio je znaĉajno povećan, a aktivnost enzima nitrat-reduktaze značajno smanjena, kod većine genotipova. Genotipovi kod kojih u uslovima jakog vodnog deficita nije došlo do značajne promene većine ispitivanih morfo-anatomskih, fizioloških i biohemijskih parametara mogu biti od velike važnosti kad je u pitanju njihov odabir i upotreba za uspešno pošumljavanje sušnih staništa, kojih će biti sve više usled negativnog uticaja brojnih ekoloških činilaca nastalih kao posledica klimatskih promena.<br>The impact of water deficit and recovery on physiological features of the black poplar clones, as well as of the oaks populations were analyzed. The aim of this research was to indicate the potential of the studied genotypes for survival under changing environmental conditions, in accordance with current climate changes, which include the reduction in amount of rainfall and limited water availability. Obtained results have shown a specific variation of studied morpho-anatomical, physiological and biochemical parameters which depended on soil humidity on the applied treatment (control, drought followed by recovery and permanent drought), as well as on plant genotype.Water deficit on permanent drought treatment had little negative effect on plant growth of poplar clone X/32, as well as oak populations L1 and C1. Plant height stress tolerance index also confirmed good morphological adaptation to drought of these genotypes. Stomatal index was not negatively affected by water deficit in oak plants. In both experiments, a permanent drought treatment led to the largest reduction in the values of gas exchange parameters in almost all genotypes.On the other hand, concentration of photosynthetic pigments was not considerably decreased in plants exposed to water deficit, as well as the parameter Fv/Fm, in most examined plants. Compared to the control, the impact of permanent drought treatment on biochemical parameters was expected, in the most cases. Compared to the control, proline content in leaves of most examined genotypes was significantly increased on permanent drought treatment, while nitrate reductase activity was significantly decreased.Examined genotypes exhibiting slight or no reduction in values of the most examined parameters during severe drought stress, could be used for afforestation in arid sites. Arid habitats appeared to be more numerous due to the effects of global climate changes.
11
Lipková, Alica. "Návrh repliky letounu L-40 "Meta Sokol" - základní rozměry - technologie." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-227920.
Full textAbstract:
The object of the diploma thesis is a preparation of fundamentals for realization for replica of the aircraft L-40 „Meta Sokol“ matching the requirements of Certification Specification for Very Light Aeroplanes (CS-VLA). The preamble of the work deals with the changes made on the original aircraft necessary to satisfy the criterias of the above-mentioned specification. One of the main contents of the first part of the thesis is the definition of replica’s basic dimensions and preparation of aerostatic fundamentals, including longitudinal stability control. As next a suitable engine is chosen and calculation of corresponding performances is made. A detailed weight analysis and a determination of centre of gravity position (c.g. position), important for solving the stability of an airplane, is also presented. Finally, a brief description of the manufacturing process of individual components and also factors influencing the technology are discussed.
12
Bonan, Bertrand. "Assimilation de données pour l'initialisation et l'estimation de paramètres d'un modèle d'évolution de calotte polaire." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00930097.
Full textAbstract:
L'évolution des calottes polaires est régie à la fois par une dynamique d'écoulement complexe et par des mécanismes tel le glissement à la base, la température de la glace ou le bilan de masse en surface. De plus, de nombreuses boucles de rétroactions sont constatées entre les différents phénomènes impliquées. Tout ceci rend la modélisation de cette évolution complexe. Malgré tout, un certain nombre de modèles ont été développés dans cette optique. Ceux-ci font tous intervenir des paramètres influents qui dans certains cas sont peu ou pas connus. Ils nécessitent donc d'être correctement spécifiés. L'assimilation de données peut permettre une meilleure estimation de ces paramètres grâce à l'utilisation d'observations qui sont peu nombreuses en glaciologie. Dans cette thèse, nous nous intéressons à la mise en place de systèmes d'assimilation performants pour deux problèmes inverses concernant l'évolution des calottes polaires. Pour mieux nous concentrer sur ce point, nous avons travaillé avec un modèle d'évolution de calotte simplifié (appelé Winnie) qui, cependant, représente bien la plupart des processus complexes de la dynamique de la glace, et permet de travailler à différentes échelles de temps. Dans un premier temps, nous mettons en place une approche 4D-Var pour la reconstruction de l'évolution d'un paramètre climatique influant sur l'évolution d'une calotte sur une échelle de temps typique de 20 000 ans. Elle nécessite notamment l'écriture du code adjoint du modèle. Dans un second temps, nous nous intéressons au problème du spin-up. Ce problème de calibration du modèle pour des simulations à échelle de temps courtes (pas plus de 100 ans) consiste plus particulièrement en la reconstruction conjointe de l'état initial, de la topographie du socle rocheux et des paramètres de glissement basal. Nous développons ici une approche filtre de Kalman d'ensemble pour résoudre ce problème.
13
Chen, Shih-Kang, and 陳式康. "Optimum Parameters for Four-Parameter Corresponding-States Principle of Polar Fluids." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/x84j42.
Full textAbstract:
碩士<br>國立臺北科技大學<br>化學工程研究所<br>95<br>This research was based on a four-parameter generalized correlation equation for saturated vapor pressure by Z. X. Shih who used saturated vapor pressure data, critical temperature and critical pressure of polar fluid to establish a new four-parameter generalized correlation equation by adding a cross term. The reference fluid of cross term was water and methanol. In this research, the saturated vapor pressure data and temperature were taken into this equation and then the new two parameters, ωn and ωp, were obtained by nonlinear regression. The new two parameters mean shape and polarity effect. The overall AAD％ was 0.820028％. On the other hand, this research was extended to saturated liquid densities. The new two parameters, ωn and ωp, of polar fluid for saturated liquid densities were obtained by the same process. The ωn and ωp of polar fluid for saturated liquid densities was compared with it for saturated vapor pressure. The overall AAD％ for saturated liquid densities in this research was 0.49374％.
14
Yaddanapudi, G. R. Krishna. "Effect of Process Parameters on the Growth of N-Polar GaN on Sapphire by MOCVD." Thesis, 2016. http://etd.iisc.ac.in/handle/2005/2662.
Full textAbstract:
Group III-Nitrides (GaN, InN & AlN) are considered one of the most important class of semiconducting materials after Si and GaAs. The excellent optical and electrical properties of these nitrides result in numerous applications in lighting, lasers, and high-power/high-frequency devices. Due to the lack of cheap bulk III- Nitride substrates, GaN based devices have been developed on foreign substrates like Si, sapphire and SiC. These technologies have been predominantly developed on the so called Ga-polarity epitaxial stacks with growth in the [0001] direction of GaN. It is this orientation that grows most easily on sapphire by metal organic chemical vapor deposition (MOCVD), the most common combination of substrate and deposition method used thus far. The opposite [000¯1] or N-polar orientation, very different in properties due to the lack of an inversion centre, offers several ad- vantages that could be exploited for better electronic and optoelectronic devices. However, its growth is more challenging and needs better understanding.
The aim of the work reported in this dissertation was a systematic investigation of the relation between the various growth parameters which control polarity, surface roughness and mosaicity of GaN on non-miscut sapphire (0001) wafers for power electronics and lighting applications, with emphasis on the realization of N-polar epitaxial layers. GaN is grown on sapphire (0001) in a two-step process, which involves the deposition of a thin low temperature GaN nucleation layer (NL) on surface modified sapphire followed by the growth of high temperature device quality GaN epitaxial layer. The processing technique used is MOCVD. Various processing methods for synthesis of GaN layers are described with particular em- phasis on MOCVD method. The effect of ex situ cleaning followed by an in situ cleaning on the surface morphology of sapphire (0001) wafers is discussed. The characterization tools used in this dissertation for studying the chemical bond nature of nitrided sapphire surface and microstructural evolution (morphological and structural) of GaN layers are described in detail.
The effect of nitridation temperature (TN) on structural transformation of non- miscut sapphire (0001) surface has been explored. The structural evolution of nitrided layers at different stages of their process like as grown stage and thermal annealing stage is investigated systematically. The chemical bond environment information of the nitrided layers have been examined by x-ray photoelectron spectroscopy (XPS). It is found that high temperature nitridation (TN ≥ 800oC) results in an Al-N tetrahedral bond environment on sapphire surface. In contrast, low temperature nitridation (TN = 530oC) results in a complex Al-O-N environment on sapphire surfaces. Microstructural evolution of low temperature GaN NLs has been studied at every stage of processing by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Surface roughness evolution and island size distribution of NLs measured from AFM are discussed. It is found that NLs processed on sapphire wafers nitrided at (TN ≥ 800oC) showed strong wurtzite [0002] orientation with sub-nanometre surface roughness. In contrast, NLs processed at (TN = 530oC) showed zinc blende phase in the as grown stage with higher surface roughness, but acquired a greater degree of wurtzite [0002] orientation after thermal annealing prior to high temperature GaN growth.
Polarity, surface quality and crystal quality of subsequently grown high temperature GaN epitaxial layers is described in relation to the structure of the trans- formed nitrided layers. Higher nitridation temperatures (TN ≥ 800oC) consistently yield N-polar GaN whereas lower nitridation temperatures (TN = 530oC) yield Ga-polar GaN. It is found that the relative O atom concentration levels in nitrided layers control the density of inversion domains in N-polar GaN. The effect of various growth parameters (NH3 flow rate, growth temperature, NL thickness) on surface morphology and mosaicity of both Ga & N-polar GaN layers is discussed in detail. We report device quality N-polar GaN epitaxial layers on non-miscut sapphire (0001) wafers by careful optimization of growth temperature. It is found that lower growth temperatures (800oC) are favorable for obtaining smooth N- polar GaN layers. In contrast, N-polar GaN layers grown at higher temperatures (1000 to 1080oC) are rough with hexagonal hillocks.
15
Yaddanapudi, G. R. Krishna. "Effect of Process Parameters on the Growth of N-Polar GaN on Sapphire by MOCVD." Thesis, 2016. http://etd.iisc.ernet.in/handle/2005/2662.
Full textAbstract:
Group III-Nitrides (GaN, InN & AlN) are considered one of the most important class of semiconducting materials after Si and GaAs. The excellent optical and electrical properties of these nitrides result in numerous applications in lighting, lasers, and high-power/high-frequency devices. Due to the lack of cheap bulk III- Nitride substrates, GaN based devices have been developed on foreign substrates like Si, sapphire and SiC. These technologies have been predominantly developed on the so called Ga-polarity epitaxial stacks with growth in the [0001] direction of GaN. It is this orientation that grows most easily on sapphire by metal organic chemical vapor deposition (MOCVD), the most common combination of substrate and deposition method used thus far. The opposite [000¯1] or N-polar orientation, very different in properties due to the lack of an inversion centre, offers several ad- vantages that could be exploited for better electronic and optoelectronic devices. However, its growth is more challenging and needs better understanding.
The aim of the work reported in this dissertation was a systematic investigation of the relation between the various growth parameters which control polarity, surface roughness and mosaicity of GaN on non-miscut sapphire (0001) wafers for power electronics and lighting applications, with emphasis on the realization of N-polar epitaxial layers. GaN is grown on sapphire (0001) in a two-step process, which involves the deposition of a thin low temperature GaN nucleation layer (NL) on surface modified sapphire followed by the growth of high temperature device quality GaN epitaxial layer. The processing technique used is MOCVD. Various processing methods for synthesis of GaN layers are described with particular em- phasis on MOCVD method. The effect of ex situ cleaning followed by an in situ cleaning on the surface morphology of sapphire (0001) wafers is discussed. The characterization tools used in this dissertation for studying the chemical bond nature of nitrided sapphire surface and microstructural evolution (morphological and structural) of GaN layers are described in detail.
The effect of nitridation temperature (TN) on structural transformation of non- miscut sapphire (0001) surface has been explored. The structural evolution of nitrided layers at different stages of their process like as grown stage and thermal annealing stage is investigated systematically. The chemical bond environment information of the nitrided layers have been examined by x-ray photoelectron spectroscopy (XPS). It is found that high temperature nitridation (TN ≥ 800oC) results in an Al-N tetrahedral bond environment on sapphire surface. In contrast, low temperature nitridation (TN = 530oC) results in a complex Al-O-N environment on sapphire surfaces. Microstructural evolution of low temperature GaN NLs has been studied at every stage of processing by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Surface roughness evolution and island size distribution of NLs measured from AFM are discussed. It is found that NLs processed on sapphire wafers nitrided at (TN ≥ 800oC) showed strong wurtzite [0002] orientation with sub-nanometre surface roughness. In contrast, NLs processed at (TN = 530oC) showed zinc blende phase in the as grown stage with higher surface roughness, but acquired a greater degree of wurtzite [0002] orientation after thermal annealing prior to high temperature GaN growth.
Polarity, surface quality and crystal quality of subsequently grown high temperature GaN epitaxial layers is described in relation to the structure of the trans- formed nitrided layers. Higher nitridation temperatures (TN ≥ 800oC) consistently yield N-polar GaN whereas lower nitridation temperatures (TN = 530oC) yield Ga-polar GaN. It is found that the relative O atom concentration levels in nitrided layers control the density of inversion domains in N-polar GaN. The effect of various growth parameters (NH3 flow rate, growth temperature, NL thickness) on surface morphology and mosaicity of both Ga & N-polar GaN layers is discussed in detail. We report device quality N-polar GaN epitaxial layers on non-miscut sapphire (0001) wafers by careful optimization of growth temperature. It is found that lower growth temperatures (800oC) are favorable for obtaining smooth N- polar GaN layers. In contrast, N-polar GaN layers grown at higher temperatures (1000 to 1080oC) are rough with hexagonal hillocks.
16
Liou, Sheng-Shian, and 劉昇弦. "A study of the effect on the Proton Exchange Membrane Fuel Cell by fractal polar plates and control parameters." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/43052570567739945874.
Full textAbstract:
碩士<br>國立勤益科技大學<br>冷凍空調系<br>99<br>Fuel cell is a type of low pollution and high efficiency energy device, which has the characteristics of the quick start-up, low noise, and long operation life. This research mainly discover the effect of reactive area and the geometry of the membrane electrolyte assembly(MEA) on the proton exchange membrane fuel cell(PEMFC).In addition, the fuel cell performance is further enhanced via the combination of different reactive area MEA and different geometric polar plates. This thesis mainly discover two parts. The first part is the analysis of the effect of the operating parameters for the fuel cell with different reactive area. The parameters the screw torque of the fuel cell, gas flow rate, gas temperature, and the heating temperature of the fuel cell. The experimental results would conclude a better operating condition of the fuel cell. The second part is the investigation of the effect on the fuel cell performance by the fractal polar plates. In the research, the Hilbert curve fractal geometry is applied to the polar plate design of the PEMFC and then discover the effect on the fuel cell performance by the free opening ratio and free opening perimeter of the polar plates.
17
Hájková, Anna. "Porovnání funkcí sporttesterů určených pro řízení a kontrolu parametrů pohybu ve vodě." Master's thesis, 2021. http://www.nusl.cz/ntk/nusl-437822.
Full textAbstract:
Title: Comparison of functions of sports testers designed for control and monitoring of parameters of movement in water Objectives: Comparison and evaluation of individual functions of selected sport-testers in different types of swimming training. Methods: The research group consisted of one probande, a student of Charles University FTVS. In the research, we chose a controlled observation method to detect and compare the individual functions of selected sports testers over three types of swimming training. Results: Based on an analysis of the accuracy of the recording of observed quantities for individual sporttesters, we found that the sporttesters Polar and Garmin can be used both to manage and guide and control swimming training. However, the final record needs to be supplemented by the exact sum of the swimming metres, which in turn refines the results of the average swimming speed. The Swimmo sports tester was rated the worst, based on inaccurate measurements of individual quantities and instrument control. In an overall assessment of all devices and their parameters, the Sporttester Polar was the best. Keywords: heart rate, swimming training, Garmin, Polar, Swimmo
18
WILDING, WADE VINCENT. "A FOUR-PARAMETER CORRESPONDING STATES METHOD FOR THE PREDICTION OF THERMODYNAMIC PROPERTIES OF POLAR AND NONPOLAR FLUIDS." Thesis, 1985. http://hdl.handle.net/1911/15941.
Full textAbstract:
A four-parameter corresponding states correlation has been developed for the prediction of thermodynamic properties of nonpolar and polar fluids. The property of a fluid is given as a Taylor's series expansion about the simple fluid property at the same reduced conditions in terms of geometric and polar deviations. Three reference fluids are used to evaluate the terms of the series. The first, a simple fluid, and the second, an acentric fluid, are adopted from the Lee-Kesler three-parameter correlation. The third, a polar fluid, is water, represented by the Keenan and Keyes equation of state.
The four parameters required are the critical temperature and pressure, and two newly developed parameters which account for geometry and polarity, respectively. The geometric parameter is obtained from the radius of gyration, and the polarity parameter is derived from one liquid density point, or alternatively from the heat of vaporization (for derivative properties).
The method, in the form of an easily used computer program, is used to obtain estimates of compressibility factors, enthalpy and entropy departure functions, and fugacity coefficients. The temperature and pressure of the fluid are specified, upon which an estimate of the desired property is calculated. The phase of the fluid may also be specified, but if unknown it is determined from a newly developed vapor-pressure correlation which is an extension to polar fluids of the Lee-Kesler nonpolar-fluid correlation. Extensive tables are also given for hand calculations.
The method has been tested on both nonpolar and polar fluids and yields results equivalent to those obtained by the Lee-Kesler three-parameter method for nonpolar fluids and better results than existing methods for polar fluids. Average errors for the compressibility factor of polar fluids for all points tested are 1.9% for the vapor phase and 1.6% for the liquid phase. Average errors for enthalpy departure functions are 250 J/mol for the vapor phase and 422 J/mol for the liquid phase. Preliminary mixture results indicate that the method will be effective for mixture property predictions as well.
19
Shih, Zhuang-Xin, and 施壯欣. "A New Four-Parameter Corresponding States Principle of Nonpolar and Polar Fluids for Saturated Vapor Pressure, Saturated Densities." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/74407500838733463002.
Full textAbstract:
碩士<br>國立臺北科技大學<br>化學工程系碩士班<br>92<br>For this research, first, The methodology of corresponding states principle (CSP) was used to developed the generalized correlation according to saturated liquid densities experimental data for nonpolar fluids, acentric factor and critical properties for nonpolar substances. Besides, a new extended corresponding-states principle generalized correlation for saturated vapor pressure was developed. This correlation requires four parameters, the critical temperature, the critical pressure, and new two parameters(ωh、ωp). The new two parameters means shape and polarity effect. On the other hand, Finally, by the use of new generalized correlation equations, the comparisons with the experimental data and calculation of the weak polar fluids function. The absolute average deviation is 0.73% for vapor pressure and 5.389% for the saturated liquid densities.
20
Muras, Jan. "Analiza pola elektromagnetycznego w nagrzewnicach indukcyjnych ze wzbudnikami wielowarstwowymi." Rozprawa doktorska, 1990. https://repolis.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=3438.
Full text
21
Muras, Jan. "Analiza pola elektromagnetycznego w nagrzewnicach indukcyjnych ze wzbudnikami wielowarstwowymi." Rozprawa doktorska, 1990. https://delibra.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=3438.
Full text
22
Staszak, Jan. "Analiza pola elektromagnetycznego turbogeneratora dużej mocy z uwzględnieniem rzeczywistej struktury wirnika." Rozprawa doktorska, 1986. https://repolis.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=3591.
Full text
23
Staszak, Jan. "Analiza pola elektromagnetycznego turbogeneratora dużej mocy z uwzględnieniem rzeczywistej struktury wirnika." Rozprawa doktorska, 1986. https://delibra.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=3591.
Full text
24
Przyłucki, Roman. "Wspomaganie komputerowe projektowania nagrzewnic indukcyjnych do wsadów płaskich." Rozprawa doktorska, 1999. https://repolis.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=2958.
Full text
25
Przyłucki, Roman. "Wspomaganie komputerowe projektowania nagrzewnic indukcyjnych do wsadów płaskich." Rozprawa doktorska, 1999. https://delibra.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=2958.
Full text