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1
Karmakar, Achintya. « Dispersion and absorption phenomena of dipolar liquid in nonpolar solvent ». Thesis, University of North Bengal, 2007. http://hdl.handle.net/123456789/662.
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Bleasdale, Thomas Anthony. « Surfactant liquid crystals in a range of polar solvents ». Thesis, University of Salford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334033.
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Dale, Alan David. « The oxidation of highly polar stationary phases in gas-liquid chromatography ». Thesis, University of Hertfordshire, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254484.
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Dhakal, Subas. « Statistical Mechanics of Polar, Biaxial and Chiral Order in Liquid Crystals ». Kent State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=kent1277740472.
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Ross, P. « The use of porous graphitic carbon in liquid chromatography performance and polar retention effect ». Thesis, University of Edinburgh, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529492.
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This thesis is primarily concerned with the use and development of Porous Graphitic Carbon (PGC) for High Performance Liquid Chromatography (HPLC). Chromatographic studies carried out using PGC since its introduction in 1988 have shown it to posses quite unique separating properties. In particular the media has been shown to be very selective for the separation of closely related compounds such as geometric and diastereoisomers. It has also been shown to be very retentive towards compounds of increasing polarity. The magnitude of this interaction is considerable, we define it as the retention over and above that which might have been predicted if the polar functional group was replaced with a non polar group of similar size. We have called this effect, the Polar Retention Effect on Graphite (PREG). Previous attempts to correlate retention on graphite with energies associated with those molecular interactions associated with other chromatographic media have been largely unsuccessful. This has in part been due to the fact that there has been no attempt to measure in units of energy the magnitude of PREG. The main body of the thesis is then concerned with experiments, which provide information regarding the magnitude of PREG. We investigate a) the relative strength of analyte/graphite interactions to that of analyte/solvent interactions, b) the effect of coating discrete or polymeric molecules to the graphite surface on PREG and c) measure the energy associated with PREG for a range of analytes and correlate this energy with physical and calculated parameters associated with each analyte. In order to gain a measure of PREG we have developed a method which allows PREG to be measured and quantified. Based on our values of PREG we have put forward a hypothesis for the mechanism responsible for this interaction. Further work still needs to be done to strengthen this hypothesis, we therefore put forward a number of ideas and suggestions for future workers to which continue to investigate the mechanism associated with PREG.
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Scapello, Justin Thomas. « Solvent extraction of a polar solute using colloidal liquid aphrons : stability, equilibrium and mass transfer ». Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265955.
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Ma, Wai Tang. « Analysis of polar nitroaromatics in groundwater by using solid-phase extraction and liquid chromatography-mass spectrometry ». HKBU Institutional Repository, 2004. http://repository.hkbu.edu.hk/etd_ra/581.
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FILHO, JOAQUIM IGNACIO BAPTISTA CARDOSO. « QUANTIFICATION OF NI AND V IN POLAR FRACTIONS OF CRUDE OIL USING LIQUID CHROMATOGRAPHY AND ICPMS ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=15413@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICONi e V ocorrem em frações polares de óleos brutos e são de interesse geoquímico. Um método foi desenvolvido para isolar e quantificar esses metais associados a compostos orgânicos chamados porfirinas, usando-se cromatografia líquida e espectrometria de massa com plasma indutivamente acoplado (ICPMS). A fração do óleo contendo parafinas, aromáticos e polares foi separada usando-se uma coluna de vidro de 25 cm x 2,5 cm preenchida com sílica gel, empregando-se um programa automatizado de gradiente de eluição com ordem crescente da polaridade dos solventes. O eluido foi analisado por espectrofotometria UV-vis e o cromatograma obtido permitiu a distinção de três frações, que foram analisadas separadamente por ICPMS. O sistema de introdução de amostra do ICPMS consistiu em um micronebulizador concêntrico de Teflon acoplado a uma câmara refrigerada a - 14 ºC. Oxigênio foi introduzido no gás de nebulização (Ar) para evitar a formação de carbono na interface do instrumento. As condições operacionais foram otimizadas por planejamento experimental. A vazão de Ar foi de 0,46 L min(-1) e a de O2 foi de 0,1 L min(-1), a 1350 W. Os limites de detecção para o V e o Ni foram de 29 e 465 ng L(-1) respectivamente. A concentração de Ni foi de (7,1 +- 0,8), (16,8 +- 1,6) e (12 +- 2) ug g-1 para as frações 1, 2 e 3 respectivamente. O V foi quase que exclusivamente encontrado na terceira fração (mais polar) com (30 + 3) ug g(-1). Esses resultados sugerem a associação do V com frações mais pesadas do óleo.
Ni and V occur in the polar fraction of crude oils and have geochemical interest. A method was developed for isolating and quantifying these metals associated with organic compounds like porphyrins, using liquid chromatography and inductively coupled plasma mass spectrometry (ICPMS). The oil fraction containing paraffins, aromatics and polars was separated using a glass column of 25 cm x 2.5 cm filled with silica gel. An automatic elution program was used to create a solvent elution gradient of increasing polarity. The column eluate were analyzed by UV-vis spectrophotometry and the chromatograms obtained showed the separation of three fractions, which were then analyzed separately by ICPMS. The ICPMS sample introduction system consisted of a concentric Teflon micronebulizer coupled to a refrigerated spray chamber set to - 14 ºC. Oxygen was introduced into the nebulization gas flow to prevent de formation of carbon at the instrument interface. Operational conditions were optimized by experimental design. The optimum gas flow rates were 0.46 L min - 1 (Ar) and 0.1 L min - 1 (O2), at 1350 W.
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Ghosh, Nilanjan. « Structural and associational aspects of some dielectropolar liquid molecules in non polar solvents from relaxation phenomena ». Thesis, University of North Bengal, 2002. http://hdl.handle.net/123456789/670.
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Johnston, Stephen Jaye. « Molecular dynamics studies of a generalised multipole model of molecular asymmetry in apolar and polar liquid crystals ». Thesis, Coventry University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369971.
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Russell, J. J. « Development of generic methods for the analysis and purification of polar compounds by high performance liquid chromatography ». Thesis, University of the West of England, Bristol, 2016. http://eprints.uwe.ac.uk/28136/.
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Generic methods were developed using different columns for analysis and purification of hydrophilic compounds by hydrophilic interaction chromatography (HILIC). Mobile phases were investigated in detail, and across each column chemistry tested (BEH Amide, Atlantis bare silica, ZIC-HILIC and Cogent Hydride), salt-buffered mobile phase offered good to excellent peak shape for acids, bases and neutral solutes with a range of hydrophilicities. Additionally, cation exchange occurred on the bare silica column even when rubidium nitrate was added to the mobile phase, which should block all cation exchange sites. Measurement of mobile phase pH in hydroorganic solvent (ACN-water mixture with buffer) better represented the environment solutes experience on column than fully-aqueous pH measurement. The performance of HILIC with Charged Aerosol Detection (CAD) was evaluated with a hydrophilic acid, a hydrophobic base and a hydrophilic neutral solute; limits of detection and quantitation were 1-3 ng and 5-9 ng on column, respectively. This compared favourably to literature values for other universal detectors. HILIC-CAD was further investigated by flow injection analysis (FIA) using 29 solutes containing acids, bases and neutrals. HILIC and CAD had excellent compatibility: peak areas were double compared to reversed-phase conditions, response was reasonably uniform for 21 non-volatile solutes considering the solutes’ diversity. HILIC-CAD was viable for retention and detection of highly hydrophilic species without chromophores: salts, sugars and amino acids. Salts travelled down the column as independent cations and anions. Resolution of sugars and amino acids was challenging and was incomplete due to project time constraints. Generic methods were developed on an analytical system in the labs of the industrial collaborator and applied to purifications on wide-bore columns at scaled-up flow rates (21mm id, 20mL/min prep vs. 4.6mm id 1 mL / min analytical analytical). A standard prep system was capable of usable productivity using HILIC with 1mL injections (22 mg of crude purified per hour) and use of At-Column Dilution enhanced this around 10-fold with scope for 4mL injections (223 mg of crude purified per hour).
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Quach, Van. « Evaluation of polar-embedded reversed-phase liquid chromatography columns and the temperature dependence of the phase ratio ». Tallahassee, Fla. : Florida State University, 2009. http://etd.lib.fsu.edu/theses/available/etd-09012009-164008/.
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Thesis (Ph. D.)--Florida State University, 2009.Advisor: John G. Dorsey, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed Mar. 5, 2010). Document formatted into pages; contains x, 99 pages. Includes bibliographical references.
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Salas, Acosta Daniela. « Strategies to improve the determination of polar compounds in environmental waters ». Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/401584.
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La present Tesi Doctoral descriu l'aplicació d'estratègies recents, enfocades a millorar la determinació de compostos polars, per desenvolupar nous mètodes per a l'anàlisi d'aigües ambientals. Aquestes estratègies s'han aplicat en dues tècniques alternatives, desenvolupades per solucionar els problemes associats a compostos polars: la cromatografia de líquids d'interacció hidrofílica (HILIC) i l'extracció en fase sòlida utilitzant sorbents polimèrics d'intercanvi iònic de mode mixt. Els mecanismes de retenció en HILIC, influència dels paràmetres cromatogràfics, avantatges i el seu acoblament a l'espectrometria de masses d'alta resolució, van ser investigats per contaminants poc estudiats per aquesta modalitat cromatogràfica alternativa. L'aplicació de sorbents de mode mixt va ser ampliada més enllà dels seus usos convencionals, proposant la seva aplicació per a l'extracció selectiva de compostos neutres capaços d'establir dipols induïts, i l'extracció simultània i selectiva de compostos bàsics i àcids. Aquesta última es va aconseguir ja sigui mesclant físicament els materials i també preparant sorbents nous modificats amb caràcter zwiteriònics.La presente Tesis Doctoral describe la aplicación de estrategias recientes, enfocadas en mejorar la determinación de compuestos polares, para desarrollar nuevos métodos para el análisis de aguas ambientales. Estas estrategias se aplican en dos técnicas alternativas, desarrolladas para solventar los problemas asociados a compuestos polares: la cromatografía de líquidos de interacción hidrofílica (HILIC) y la extracción en fase sólida utilizando sorbentes poliméricos de intercambio iónico de modo mixto. Los mecanismos de retención en HILIC, influencia de los parámetros cromatográficos, ventajas, y su acoplamiento a la espectrometría de masas de alta resolución, fueron investigados para contaminantes poco estudiados por este modo cromatográfico alternativo. La aplicación de sorbentes de modo mixto fue ampliada más allá de sus usos convencionales, proponiendo su aplicación para la extracción selectiva de compuestos neutros capaces de establecer dipolos inducidos, y la extracción simultánea y selectiva de compuestos básicos y ácidos. Esta última fue lograda bien sea combinando físicamente los materiales o preparando sorbentes nuevos con carácter zwitteriónico.
This Doctoral Thesis describes the application of recent strategies focused on improving the determination of polar compounds, to develop new methods for the analysis of environmental waters. These strategies are applied in two alternative techniques developed to address problems associated to polar compounds: hydrophilic interaction liquid chromatography (HILIC) and solid-phase extraction using mixed-mode ion-exchange polymeric sorbents. The HILIC retention mechanisms, influence of chromatographic parameters, advantages and its coupling with high-resolution mass spectrometry, were investigated for contaminants seldom studied by this alternative chromatographic mode. The application of mixed-mode sorbents was broadened beyond their conventional uses, proposing their application for the selective extraction of neutral compounds capable of establishing induced dipoles, and the simultaneous and selective extraction of basic and acidic compounds. The latter was achieved by either physically combining the materials or preparing new sorbents with zwitterionic character.
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Miao, Yiqing. « Compositional viscosity and microfiltration properties of ionic liquid-polar solvent mixtures and investigation of ionic liquids as enzyme carrier for bioreactions in a membrane reactor ». Thesis, Queen's University Belfast, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.546429.
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Bennett, Raffeal. « Gradient Enhanced Fluidity Liquid Chromatography using the Hydrophilic Interaction Separation Mode ». The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1500995708235286.
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Samskog, Jenny. « Development of Micro Liquid Separation Techniques using Electrospray Ionisation Mass Spectrometry in the Analysis of Polar Compounds and Proteins/Peptides ». Doctoral thesis, Uppsala University, Analytical Chemistry, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3304.
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Electrospray ionisation (ESI) coupled to mass spectrometry (MS) is one of the most important detection techniques for chemical analysis of small drugs as well as large biomolecules in life science today. In this thesis, aspects on improved compatibility between liquid based separation systems and mass spectrometric detection were investigated regarding buffers, sample preparation and analysis of polar compounds as well as peptides and protein digests for enhanced ESI-MS performance.
Capillary electrophoresis (CE) coupled to ESI-MS detection, was evaluated using both a sheath flow interface and a sheathless design. The separation of peptides and small, polar compounds was optimised for both CE-ESI interfaces. The effect of sheath liquid composition was also studied with the aim to improve sensitivity in the ESI-MS detection.
Polar compounds were retained and separated by capillary ion-pair chromatography coupled to ESI-MS detection. Since commonly used ion-pairing reagents are detrimental to the ESI process they were effectively removed before the ionisation by the use of a trapping column after the separation. Alternatively, the ion-pairing reagents were exchanged to volatile constituents.
A method for peptide mapping by liquid chromatography (LC)-ESI-MS was developed for lactate dehydrogenase. The method was further enhanced to involve the proteolysis on-line to the LC-ESI-MS. No manual sample handling was then needed and the total analysis time decreased from 7 to 1.5 hours. The amount of information was also shown to increase in the on-line system.
Finally, the on-line concept was extended to an innovative interface for direct coupling of a pumped liquid flow to an electroosmotically driven flow. This provided a valve-free sample transfer between capillary LC and CE, aiming towards increased peak capacity per unit time for the analysis of complex peptide samples.
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Rosa, Rafaela Raupp da. « Isoxazolinas e isoxazóis como reais candidatos na preparação de cristais líquidos polares ». reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/180639.
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A presente tese descreve a síntese e caracterização de 10 novas séries de moléculas na forma de banana contendo os anéis isoxazolina e isoxazol como reais candidatos na preparação de cristais líquidos polares. Foram avaliados parâmetros estruturais tais como o tipo de função conectora do centro curvado com os braços mesogênicos, a natureza do heterociclo e a sua posição relativa ao núcleo. A síntese dos compostos contou com a metodologia de preparação do anel isoxazolina, a cicloadição [3+2] 1,3-dipolar entre alcenos e óxidos de nitrila, os quais foram gerados pelas oximas preparadas a partir de aldeídos alifáticos e aromáticos. Todas as isoxazolinas foram oxidadas aos seus respectivos isoxazóis utilizando dióxido de manganês. Foram utilizadas ainda reações de alquilação, redução, desproteção, hidrogenólise, olefinação, adição de aminas à aldeídos e esterificação. Todas as moléculas sintetizadas foram caracterizadas por RMN de 1H e 13C, além de serem observadas por MOLP para determinação dos seus pontos de fusão. As moléculas que apresentaram comportamento mesomórfico foram ainda caracterizadas por DSC, XRD e voltagem triangular. No capítulo 3 é descrita a síntese dos isoftalatos 19a-b, 20a-b, 26a-b e 27a-b. No subgrupo dos Isoftalatos derivados de isoxazóis e isoxazolinas 3,5-diarilsubstituídos foi possível a síntese apenas do composto 11d que não apresentou comportamento líquido cristalino No subgrupo dos isoftalatos derivados de isoxazóis e isoxazolinas 3-alquil-5-arilsubstituídos as isoxazolinas 19a-b não apresentaram comportamento líquido-cristalino. Foram encontradas mesofases para os compostos 20a-b que ainda não foram determinadas com as técnicas disponíveis. Os isoxazóis 20a-b apresentaram uma provável Blue Phase logo após o resfriamento do isotrópico, que rapidamente se converte em uma provável mesofase monotrópica ferroelétrica com texturas e padrão de XRD peculiares até então não observada na literatura. No subgrupo dos isoftalatos derivados de isoxazóis e isoxazolinas 3-aril-5-alquilsubstituídos 26a-b e 27a-b não foi observado comportamento líquido-cristalino. O capítulo 4 descreve a síntese das isoftaliminas 35, 36, 44, 45, 50a-b, 51a-b, 56a-d, 57a-d, 63a-b e 64a-b. No subgrupo dos isoxazóis e isoxazolinas 3,5-diarilsubstituídos 35, 36, 44 e 45 foram observadas as mesofases B7 e B1 apenas com a inversão da orientação do anel isoxazol como braçomesogênicos dos compostos finais, enquanto que as isoxazolinas não apresentaram mesofases. A mesofase B7 do composto 36 apresentou comportamento antiferroelétrico enquanto que a mesofase B1 do composto 45 não mostrou resposta frente ao campo elétrico aplicado, além disso, o XRD mostrou que tal mesofase colunar B1 pode ser uma fase 3D modulada. No subgrupo das isoxazolinas e isoxazóis 3-alquil-5-arilsubstituídos 50a-b e 51a-b foram observadas fases do tipo DC para as isoxazolinas 50a-b, a qual deve ser confirmada por FFTEM. No subgrupo dos materiais 3-aril-5-alquilsubstituídos 56a-d, 57a-d, 63a-b e 64a-b foram observadas mesofases SmXPF para os compostos 56b-d. Os isoxazóis 57a-d apresentaram texturas similares, porém não apresentaram mesofase, mas os mesmos seguem o mesmo padrão de difração das isoxazolinas do capítulo 3. Apenas a isoxazolina 63b dos compostos perfluorados apresentou mesofase No capítulo 5 é descrita a síntese de ésteres não-simétricos contendo os heterociclos isoxazol e isoxazolinas como núcleo central 71a-f, 82, 83, 84 e 85. No primeiro subgrupo todos os ésteres cinâmicos 71a-f apresentaram comportamento mesomórfico com grandes faixas de temperaturas nas mesofases. No segundo subgrupo as isoxazolinas 82 e 83 apresentaram comportamento completamente distinto, onde só foi observada a formação de uma mesofase SmB para o composto que tem a posição éster localizada na direção do nitrogênio do heterociclo. Já os isoxazóis 84 e 85 deste subgrupo apresentaram as mesofases N e SmC em temperaturas bastante similares, porém, a observação desses materiais em uma cela alinhada revelou o crescimento de filamentos na transição N-SmC apenas para o composto 85, o qual também possui a porção éster na direção do nitrogênio do anel isoxazol. O capítulo 6 traz a síntese dos ésteres e iminas simétricos 88, 89, 94 e 95 utilizando os heterociclos como núcleo central, os quais apresentaram mesofases SmC e N. Além disso, o diéster 89 derivado de isoxazol apresentou a mesma característica que o composto 85 do capítulo 5, apresentando uma transição N-SmC com crescimento de filamentos perpendiculares à direção de alinhamento da amostra dentro da cela, podendo estar relacionada à uma mesofase NTB.This thesis describe the synthesis and characterization of 10 new series of banana shaped molecules containing the isoxazoline and isoxazole rings as real players for preparation of polar liquid crystals. It was evaluate structural parameters such as the type of connecting function of the bent core with the mesogenic arms, the heterocycle nature and its position relative to the central core. The synthesis of the compounds included the methodology of preparation of the isoxazoline ring, the [3 + 2] 1,3-dipolar cycloaddition between alkenes and nitrile oxides, which were generated by the oximes prepared from aliphatic and aromatic aldehydes. Furthermore, all isoxazolines were oxidized to its respective isoxazoles using manganese dioxide. Besides the described methodologies, alkylation, reduction, deprotection, hydrogenolysis, olefination, addition of amines to the aldehydes and esterification reactions were used. All the synthesized molecules were characterized by 1H NMR and 13C NMR, and also observed by POM for determination of its melting points. The molecules previously analyzed by POM that showed mesomorphic behavior were characterized by DSC, XRD and triangular voltage still. Chapter 3 describes the synthesis of isophthalates 19a-b, 20a-b, 26a-b e 27a-b. In the subgroup of isophthalates derived from isoxazoles and isoxazolines 3,5-diarylsubstituted it was possible to synthesize only compound 11d which did not show liquid crystalline behavior In the subgroup of the isophthalates derived from isoxazoles and isoxazolines 3-alkyl-5-arylsubstituted the isoxazolines 19a-b did not show liquid crystalline behavior. It was found mesophases for compounds 20a-b that still could not be determined with the available techniques. The isoxazoles 20a-b presented a probable Blue Phase soon after cooling from the isotropic which quickly converts into a probable ferroelectric monotropic mesophase with peculiar textures and pattern of XRD until then not observed in the literature. In the subgroup of the isophthalates of isoxazoles and isoxazolines 3-aryl-5-alkylsubstituted 26a-b and 27a-b no liquid crystalline behavior was observed. Chapter 4 describes the synthesis of isophthalimines 35, 36, 44, 45, 50a-b, 51a-b, 56a-d, 57a-d, 63a-b and 64a-b. In the subgroup of the isoxazoles 3,5-diarylsubstituted 35, 36, 44 and 45 the B7 and B1 mesophases were observed only with the inversion of the isoxazole ring orientation as mesogenic arm of thefinal compounds whereas the isoxazolines did not present mesophases. The B7 mesophase of the compound 36 showed antiferroelectric switching while the B1 mesophase of the compound 45 showed no response to the applied electric field, in addition, the XRD showed that such B1 columnar mesophase could be a 3D modulated phase one. In the subgroup of 3-alkyl-5-arylsubstituted isoxazolines and isoxazoles 50a-b and 51a-b DC phases were observed for isoxazolines 50a-b which should be confirmed by FFTEM. The SmXPF mesophase were observed for componds 56b-d in the subgroup of 3-aryl-5-alkylsubstituted materials 56a-d, 57a-d, 63a-b e 64a-b. The isoxazoles 57a-d presented similar textures although did not showed mesophase, but they follow the same diffraction pattern of the chapter 3 isoxazolines. Only the isoxazoline 63b of the perfluorinated compounds showed mesophase In chapter 5 is described the synthesis of non-symmetric esters containing isoxazol and isoxazolines heterocycles as central core 71a-f, 82, 83, 84 e 85. In the first subgroup all the cinnamic esters 71a-f showed mesomorphic behavior with large mesophases temperature ranges. In the second subgroup the isoxazolines 82 and 83 showed completely different behavior which only was observed the SmB mesophase formation for compound having the ester position towards the heterocycle nitrogen. Furthermore, the isoxazoles 84 and 85 of this subgroup showed the N and SmC mesophases at very similar temperatures, however, the observation of these materials in an aligned cell revealed the filamentary growth in the N-SmC transition only for compound 85, which also has the ester moiety in the direction of the isoxazole ring nitrogen. Chapter 6 brings forward the synthesis of symmetrical esters and imines 88, 89, 94 and 95 using the heterocycles as the central cores, which showed SmC and N mesophases. Moreover, the isoxazole derived diester 89 showed the same feature as compound 85 of Chapter 5, exhibiting a N-SmC transition with filament growth perpendicular to the rubbing direction of the cell which may be related to a NTB mesophase.
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Magnér, Jörgen. « Methodologies to assess the fate of polar organic compounds in aquatic environments ». Doctoral thesis, Stockholms universitet, Institutionen för tillämpad miljövetenskap (ITM), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-35552.
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Polar organic compounds (POCs) are chemicals with polar functional groups in their structure. The functional groups make the compounds hydrophilic and less prone to partition with biota. However, the knowledge of their fate is limited due to difficulties associated with their measurements. Although, the persistence of POCs in the environment is generally low, they are considered to be semi-persistent compounds due to their continuous introduction to the environment via wastewater. Studies have shown that complex mixtures of POCs of different classes may have synergistic toxic effects on biota at environmental concentration levels. Therefore, it is important to develop analytical methods in order to establish the occurrence and fate of POCs in aquatic environments. In Study I, a positive correlation between the sorption of a novel poly(ethylene-co-vinyl acetate-co-carbon monoxide) (PEVAC) material and the theoretical logarithmic dissociation partition coefficient (Log D) for seven POCs was observed. The PEVAC material showed an enhanced sorption of the POCs compared to the silicone material. Study II, demonstrated that the PEVAC sampler assess the freely dissolved concentration of POCs in aquatic environments. The results showed that the PEVAC polymer is an attractive alternative to silicone for mimicing the biological uptake of POCs in aquatic environments. Additionally, Study II showed that total extraction is appropriate for determination of the freely dissolved concentration of uncharged POCs with Log KOW < 2.67 in natural water. In study III, a novel bag-solid phase extraction (bag-SPE) technique was compared to a conventional SPE-technique. Despite that the extraction efficiencies for POCs in wastewater were lower using the bag-SPE method, the two methods showed similar detection limits due to the lower ion-suppression experienced with the bag-SPE. In study IV the bag-SPE method was further developed with the aim of lowering the detection limits for POCs. Detection limits (LOD) below 13 ng/L showed that the bag-SPE method was suitable for determination of POCs in surface sea water.This research was financially supported by European Union (European Commission, FP6 Contract No. 003956) “Novel Methods for Integrated Risk Assessment of Cumulative Stressors in the Environment” (NoMiracle) and by the Swedish research council Formas.
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Kujawinski, Dorothea [Verfasser], Torsten Claus [Akademischer Betreuer] Schmidt et Oliver J. [Akademischer Betreuer] Schmitz. « Liquid Chromatography coupled to Isotope Ratio Mass Spectrometry of Selected Polar Compounds / Dorothea Kujawinski. Gutachter : Oliver J. Schmitz. Betreuer : Torsten Claus Schmidt ». Duisburg, 2014. http://d-nb.info/1064580912/34.
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Arroyo-Mora, Luis. « Environmental analysis of polar herbicides in complex organic-rich matrices by high performance liquid chromatography atmospheric pressure ionization mass spectrometry (HPLC-API-MS) ». FIU Digital Commons, 2003. http://digitalcommons.fiu.edu/etd/1425.
Texte intégralRésumé :
A comprehensive forensic investigation of sensitive ecosystems in the Everglades Area is presented. Assessing the background levels of contamination in these ecosystems represents a vital resource to build up forensic evidence required to enforce future environmental crimes within the studied areas. This investigation presents the development and validation of a fractionation and isolation method for two families of herbicides commonly applied in the vicinity of the study area, including phenoxy acids like 2,4-D, MCPA, and silvex; as well as the most common triazine-based herbicides like atrazine, prometyne, simazine and related metabolites like DIA and DEA. Accelerated solvent extraction (ASE) and solid phase extraction (SPE) were used to isolate the analytes from abiotic matrices containing large amounts of organic material. Atmospheric-pressure ionization (API) with electrospray ionization in negative mode (ESP-), and Chemical Ionization in the positive mode (APCI+) were used to perform the characterization of the herbicides of interest.
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Espinosa, Carlos Esteban. « Screened electrostatic interaction of charged colloidal particles in nonpolar liquids ». Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34820.
Texte intégralRésumé :
Liquid dispersions of colloidal particles play a big role in nature and as industrial products or intermediates. Their material properties are largely determined by the liquid-mediated particle-particle interaction.
In water-based systems, electric charge is ubiquitous and electrostatic particle interaction often is the primary factor in stabilizing dispersions against decomposition by aggregation and sedimentation. Very nonpolar liquids, by contrast, are usually considered free of charge, because their low dielectric constant raises the electrostatic cost of separating opposite charges above the available thermal energy. Defying this conventional wisdom, nonpolar solutions of certain ionic surfactants do support mobile ions and surface charges. Even some nonionic surfactants have recently been found to raise the conductivity of nonpolar oils and promote surface charging of suspended particles, but this counter-intuitive behavior is not yet widely acknowledged, nor is the mechanism of charging understood.
The present study provides the first characterization of the electrostatic particle interaction caused by nonionizable surfactants in nonpolar oils. The methods used in this study are video microscopy experiments where particle positions of equilibrium ensembles are obtained and translated into particle interactions.
Experimentally, equilibrium particle positions are monitored by digital video microscopy, and subjected to liquid structure analysis in order to find the energy of interaction between two particles. The observed interaction energy profiles agree well with a screened-Coulomb potential, thus confirming the presence of both surface charge and mobile ions in solution. In contrast to recently reported electrostatic particle interactions induced by ionic surfactants in nonpolar solution, the present study finds evidence of charge screening both above and below the surfactant's critical micelle concentration, CMC. Fitted Debye screening lengths are much larger than in aqueous systems, but similar to the Debye length in nonpolar oils reported for micellar solutions of ionic surfactants cite{hsu_charge_2005}.
Radial distribution functions obtained from experiments are compared to Monte-Carlo simulations with input potentials obtained from a fit to the interaction measurement. The measured electrostatic forces and fitted surface potentials are fairly substantial and easily capable of stabilizing colloidal dispersions. Although few in number, surface charges formed on polymer particle surfaces submerged in nonpolar solutions of nonionizable surfactants create surface potentials comparable to those in aqueous systems.
22
Cartwright, Richard. « Analysis of Channel Networks and the Potential for Sediment Transport in the Vicinity of the North Polar Seas of Titan ». Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/geosciences_theses/20.
Texte intégralRésumé :
This study analyzes the available radar evidence in order to describe the morphology of channel networks around the north polar seas of Titan. Critical flow depths necessary to entrain water-ice grains, and denudation rates for a north polar channel network are discussed. The results indicate that channel networks on Titan have similar morphologies to channel networks cut by water on Earth. We also find that water-ice sediment should be readily entrained in the headwaters and downstream sections of the analyzed Titanian basin, given sufficient flow depths of liquid hydrocarbons. Also, the importance of slope and the elevated topography of the highlands surrounding the polar lakes are considered, as well as potential formation theories for the elevated highlands and low-lying maria that dominate the north polar region.
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Rosa, Paulo César Pires 1976. « Preparação, caracterização da fase estacionária C8, com grupo polar uréia embutido e aplicações na análise e no desenvolvimento e validação de métodos para determinação de fármacos ». [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250527.
Texte intégralRésumé :
Orientador: Isabel Cristina Sales Fontes JardimTese (doutorado) - Universidade Estadual de Campinas, Instituto de Química
Made available in DSpace on 2018-08-17T10:43:43Z (GMT). No. of bitstreams: 1 Rosa_PauloCesarPires_D.pdf: 2764513 bytes, checksum: 8ef702d050c47af34e60cf2218efa939 (MD5) Previous issue date: 2010
Resumo: Neste trabalho, desenvolveu-se uma nova fase estacionária (FE) (-NH-C(O)-NH-C8) capeada, contendo o grupo polar uréia inserido na cadeia alquila C8. Os estudos de análise elementar, espectroscopia infravermelho, ressonância magnética nuclear de C e Si confirmaram o sucesso da síntese da FE. A FE foi preparada e foi caracterizada cromatograficamente na separação de misturas testes e de diversas classes de fármacos, no desenvolvimento e validação de métodos para avaliação de misturas de estatinas em cápsulas, clobutinol e doxilamina em xarope e para determinação de impurezas e produtos de degradação dos fármacos alprazolam e cloxazolam. As colunas recheadas com a FE Si-C8-uréia proporcionaram boas separações, com eficiências entre 60.000 e 80.000 pratos m e picos simétricos, especialmente para compostos básicos. O comportamento da nova FE foi comparado com os das FE comerciais, obtendo desempenho semelhante na separação de misturas testes e de fármacos, como furoato de mometasona em creme, conservantes como os alquilparabenos, clonazepam e impurezas, valerato de betametasona, clioquinol e tolnaftato em creme, dropropizina em xarope, mistura de paracetamol, cafeína e ácido acetisalicílico em comprimidos e mistura de cefalexina, prilocaína e amitriptilina. A FE Si-C8-uréia apresentou boa aplicabilidade na separação de fármacos devido ao grupo uréia reduzir a interação dos compostos básicos com os silanóis residuais. Dessa forma, a nova FE possui potencialidade para ser empregada em laboratórios de pesquisa e controle de qualidade, especialmente na análise de compostos básicos
Abstract: In this work, it a new end-capped stationary phase (SP) containing a urea polar group inserted into the C8 alkil chain (-NH-C(O)-NH-C8) was prepared. Elementar analysis, infrared spectroscopy and C and Si nuclear magnetic ressonance allowed confirmation of the success of the synthesis of the SP. The new SP was chromatographically caracterizeded by the separation of test mixtures and of different types of pharmaceutical compounds, in the development and validation of methods for analysis of a mixture of statins in capsules, clobutinol hydrochloride and doxilamine in syrups and for determination of impurities and degradation products of the pharmaceutical compounds alprazolam and cloxazolam. Columns containing Si-C8-urea SP showed good separations, with efficiencies between 60 000 and 80 000 plates.m and symmetrical peaks, especially for basic compounds. The behavior of the new SP was compared with commercially available SP and the results showed similar behaviors for separation of test mixtures and of pharmaceutical compounds such as mometasone furoate in creams, preservatives like alkylparabens, clonazepam and impurities, bethametasone valerate, clioquinol and tolnaftate in creams, dropropizine in syrup, mixtures of acetaminophen, caffeine and aspirin in tablets and mixtures of cefalexin, prilocaine and amitriptiline. The Si-C8-urea SP showed good applicability for separation of pharmaceutical compounds due to the urea group reducing the interaction of basic analytes with the residual silanols. Thus, the new SP has the potencial to be employed in research and for quality control, especially for the analyses of basic pharmaceutical compounds
Doutorado
Quimica Analitica
Doutor em Ciências
24
Dong, Wei. « Contribution a l'etude theorique de la structure d'un fluide polaire et d'une solution electrolytique au voisinage d'une surface solide ». Paris 6, 1987. http://www.theses.fr/1987PA066340.
Texte intégralRésumé :
Modelisation de la solution par un melange de spheres dures chargees de meme taille et de la surface solide par une paroi dure de constante dielectrique unite. Resolution des equations integrales couplees associees au modele de la chaine hyperreticulee de reference (rhnc). Bonne description du profil densite-orientation pour un fluide dipolaire pur et accord avec les calculs par la methode de monte carlo. Construction d'une fonctionelle de densite pour decrire les effets orientationnels. Mise en evidence de deux effets importants dans le profil ionique: un effet de densite du a la granularite du solvant et un effet de force image repulsive engendre par la discontinuite dielectrique a la surface, avec appauvrissement en ions au voisinage de la surface. Analyse detaillee de la theorie du couplage faible appliquee a un melange d'ions et de dipoles ponctuels: certains diagrammes de type "bridge" contribuent au comportement asymptotique du profil ionique loin de la surface et permettent de reconcilier les resultats de la theorie microscopique avec ceux de l'electrostatique des milieux continus
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Törnkvist, Anna. « Aspects of Porous Graphitic Carbon as Packing Material in Capillary Liquid Chromatography ». Doctoral thesis, Uppsala University, Analytical Chemistry, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3306.
Texte intégralRésumé :
In this thesis, porous graphitic carbon (PGC) has been used as packing material in packed capillary liquid chromatography. The unique chromatographic properties of PGC has been studied in some detail and applied to different analytical challenges using both electrospray ionization-mass spectrometry (ESI-MS) and ultra violet (UV) absorbance detection.
The crucial importance of disengaging the conductive PGC chromatographic separation media from the high voltage mass spectrometric interface has been shown. In the absence of a grounded point between the column and ESI emitter, a current through the column was present, and changed retention behaviors for 3-O-methyl-DOPA and tyrosine were observed. An alteration of the chromatographic properties was also seen when PGC was chemically oxidized with permanganate, possibly due to an oxidation of the few surface groups present on the PGC material.
The dynamic adsorption of the chiral selector lasalocid onto the PGC support resulted in a useful and stable chiral stationary phase. Extraordinary enantioselectivity was observed for 1-(1-naphthyl)ethylamine, and enantioseparation was also achieved for other amines, amino acids, acids and alcohols.
Finally, a new strategy for separation of small biologically active compounds in plasma and brain tissue has been developed. With PGC as stationary phase it was possible to utilize a mobile phase of high content of organic modifier, without the addition of ion-pairing agents, and still selectively separate the analytes.
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Basak, Rabindra Chandra. « Dielectric behaviour of some polar liquids under high frequency electric field ». Thesis, University of North Bengal, 2000. http://hdl.handle.net/123456789/643.
Texte intégral
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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.
Texte intégral
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Russier, Vincent. « Contribution à la description théorique de l'interface métal noble / solution électrolytique ». Paris 6, 1986. https://hal.science/tel-04577395v1.
Texte intégralRésumé :
Description théorique de l'interface entre un métal noble et une solution électrolytique. La description de l'interface solution-paroi solide est décrite par le modèle "civilisé" dans lequel les molécules sont des sphères dures portant un dipôle ponctuel et les ions de sphères dures chargées. Détermination du profil de densité des dipôles lorsque ceux-ci interagissent avec la surface ainsi que le profil de densité des ions. Pour l'interface métal noble-vide, calcul du travail de sortie et de l'énergie de surface. Utilisation d'un modèle simple permettant de traiter la surface et de rendre compte de l'hybridation s/dTheoretical description of the interface between a noble metal and an electrolytic solution. The description of the solution-wall solid interface is described by the "civilized" model in which the molecules are hard spheres bearing a point dipole and the ions of charged hard spheres. Determination of the density profile of dipoles when they interact with the surface and the density profile of ions. For noble-vacuum metal interface, calculation of output work and surface energy. Use of a simple model to treat the surface and account for hybridization s/d
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Geyer, Delphine. « Du mouvement au blocage collectif dans des assemblées de rouleurs colloïdaux : hydrodynamique et solidification des liquides polaires actifs ». Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEN026/document.
Texte intégralRésumé :
Des mouvements collectifs dirigés émergent dans des systèmes très variés, depuis les assemblées synthétiques de grains vibrés jusqu'aux nuées d'oiseaux dans la nature. En essayant de comprendre le caractère générique de ces comportements dynamiques collectifs, les physiciens ont décrit les populations d'individus motiles comme des matériaux ordonnés.Dans cette thèse, nous réalisons expérimentalement des troupeaux synthétiques en laboratoire et nous explorons leurs propriétés hydrodynamiques.Nous tirons avantage du mécanisme d’électro rotation de Quincke pour motoriser des millions de colloïdes. Ces rouleurs de Quincke sont capables de s'auto-organiser pour former un troupeau appelé liquide polaire où toutes les particules se déplacent en moyenne dans la même direction.Nous montrons que la dynamique de ce liquide polaire est très bien décrite par des prédictions théoriques laissées sans preuves expérimentales depuis vingt-cinq ans. En particulier,nous démontrons que deux modes sonores s'y propagent et nous montrons que l’étude de leur spectre fournit une méthode non invasive pour mesurer ses constantes hydrodynamiques.Finalement, nous montrons que le mouvement dirigé peut être supprimé collectivement dans un troupeau dense. Un solide actif peut nucléer et se propager à contre-courant dans le liquide polaire. Nous établissons que cette solidification est une transition du premier ordre et qu'il s'agit de la première démonstration expérimentale complète d'une séparation de phase induite par la motilité des particules actives (aussi appelée MIPS)Spontaneous collective motion arises in many different systems, from assembly of synthetic shaken grains to living bird flocks. In order to understand the generic features of those collective behaviours, physisicts describe the flocks of motile units as ordered materials. In this thesis we study experimentally the dynamics of synthetic flocks and explore their hydrodynamic properties. We take advantage of the Quincke mechanism to motorize millions of colloids. Those Quincke rollers self-organize into a polar liquid, where all the particles, on average flow in the same direction. We provide the first experimental proof that the dynamics of polar liquids is well described by a theoretical prediction established more than twenty-five years ago. In particular, we demonstrate that two sound modes propagate along all directions of the fluid and we design a non invasive spectroscopic method to measure its hydrodynamics constants.Finally, we show that collective motion can be arrested in a dense flock. An active solid can nucleate, grow and propagate in a polar liquid. We establish that this solidification is a first order phase transition and demonstrate that the formation of this active solid is the first experimental proof of a complete motility induced phase separation of active particles (also known as MIPS)
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Bratkowska, Dominika. « Development and application of new polymeric materials for sorptive extraction techniques ». Doctoral thesis, Universitat Rovira i Virgili, 2011. http://hdl.handle.net/10803/63173.
Texte intégralRésumé :
El desenvolupament de diferents materials per a les tècniques d’extracció mitjançant processos de sorció és una àrea en continua expansió; no obstant, l’extracció d’anàlits polars encara és un tema que requereix més investigació. En aquesta Tesi s’han desenvolupa nous materials que reuneixen de selectivitat i/o capacitat característiques per a extreure contaminants orgànics polars en mostres aquoses. La primera part descriu el desenvolupament de nous materials polimèrics que milloren la capacitat i selectivitat de l’extracció en fase solida, i hi inclau els polímers altament entrecreuats amb caràcter hidrofílic, els sorbents altament entrecreuats d’intercanvi iònic de mode-mixte i els líquids iònics suportots en fases polimèriques; així com la seva avaluació com a nous sorbents per a la extracció de contaminats polars en diferents mostres aquoses mediambientals seguit de l’anàlisi per LC. La segona part está centrada en la preparació de noves barres agitadores amb recobriments monolítics polars i la seva posterior aplicació per l’extracció d’analits polars en diferents aigües de procedéncia mediambiental.The development of different materials for sorptive extraction techniques is a continuously evolving field of research. Although there have been significant developments in this area, the extraction of polar analytes is still considered the bottleneck of the extraction process. The efforts have been undertaken to improve capacity and selectivity. For this reason, one of the main objectives of this Thesis is to develop new materials to extract polar organic contaminants from water samples. The first part reports on the development of new polymeric materials for solid-phase extraction including hypercrosslinked polymers with hydrophilic character, mixed-mode ion-exchange hypercrosslinked sorbents and supported ionic liquid polymeric phases and their evaluation as SPE sorbents for the extraction of polar contaminants, followed by LC analysis. The second part is focused on the preparation of new stir bars with polar monolithic coatings and their application to stir bar sorptive extract polar analytes from environmental water samples.
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Bleazard, Joseph Gibson. « The thermal conductivity of aqueous electrolyte solutions and polar liquids ». Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/33419.
Texte intégral
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Braun, Heiko [Verfasser]. « Simulation of the phase behavior in polar model liquids / Heiko Braun ». Wuppertal : Universitätsbibliothek Wuppertal, 2015. http://d-nb.info/108143001X/34.
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Reighard, Tricia Susan. « Extraction of polar pollutants using supercritical fluids and enhanced-fluidity liquids / ». The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487940308432287.
Texte intégral
34
Haughney, Michael Francis. « A molecular dynamics study of selected polar liquids and their aqueous mixtures ». Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254062.
Texte intégral
35
Hunger, Johannes. « Effects of polar compounds on the dynamics and dielectric properties of room-temperature ionic liquids ». kostenfrei, 2009. http://epub.uni-regensburg.de/11973/.
Texte intégral
36
Коробко, Олександр Анатолійович. « Удосконалення резонансного діелькометричного методу контролю та визначення вологості рідких неполярних діелектриків ». Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/40781.
Texte intégralRésumé :
Дисертація на здобуття наукового ступеня кандидата технічних наук (доктора філософії) за спеціальністю 05.11.13 "Прилади і методи контролю та визначення складу речовин" (15 – Автоматизація та приладобудування) – Національний технічний університет "Харківський політехнічний інститут".
Мета роботи: удосконалення резонансного діелькометричного методу контролю та визначення вологості рідких неполярних діелектриків задля підвищення його чутливості до рівня 10⁻⁵ з одночасною мінімізацією впливу "сортової невизначеності". Запропоновані та досліджені: спрощена математична модель емульсії на основі моделі штучного діелектрика Кока; нові багаточастотні різновиди резонансного діелькометричного методу; новий тип розподіленого вимірювального перетворювача. Розроблено, теоретично та експериментально досліджено вологоміри середньочастотного та дуже високочастотного діапазонів. Експериментальним шляхом підтверджено досягнення мети роботи.Thesis for a candidate degree (PhD) in specialty 05.11.13 "Instruments and methods of control and determination of substances" (15 – Automation and Instrumentation) − National Technical University "Kharkiv Polytechnic Institute". The thesis is devoted to the improvement of the resonant dielectric method of monitoring and determining the humidity of emulsions such as liquid non-polar dielectric - water in order to increase its sensitivity to level 10⁻⁵ while simultaneously minimizing the type and grade of non-polar dielectric ("varietal uncertainty") on the measurement results. An analytical review and analysis of the existing methods and means of implementation of the dielectric method in general and its resonant variety has been carried out. The main research areas have been identified: development of a simplified emulsion model; development of new varieties of the resonant dielectric method with minimization of the effect of "varietal uncertainty" for measuring humidity at a level of 10⁻⁵; development of a new type of distributed transducer. A simplified emulsion model was chosen based on the Kok artificial dielectric model, its applications were determined by frequency, humidity, and the values of its systematic errors were determined. New multifrequency varieties of the resonant dielectric method have been developed based on the proposed mathematical model of the emulsion, taking into account the parasitic capacitances of the measuring generator and the measuring converter. Metrological characteristics of the generalized four-frequency method and its simplified three-and two-frequency varieties are obtained. The areas of applicability of multifrequency methods are analyzed and their systematic errors are determined. The most sensitive method, the two-frequency method, was determined, the effect of dielectric losses in water was analyzed for it, and the generation frequency of the measuring generator, which corresponds to its maximum sensitivity, 100 MHz, was determined. A new type of distributed-type measuring transducer is proposed for the practical implementation of the two-frequency method — a stepwise heterogeneous coaxial resonator; its theoretical and experimental studies are carried out; its advantages in relation to the known transducers are determined. A hygrometer of the mid-frequency range based on a concentrated-type capacitive transducer and a hydrometer of a very high-frequency range based on a stepped heterogeneous coaxial resonator have been developed. The circuit solutions of the measuring transducer and the measuring generator of the hygrometer of the midfrequency range, which provided the minimum values of their parasitic capacitances, were developed and implemented. The circuit solutions of the measuring transducer and the measuring generator of a hygrometer of a very high frequency range have been developed and implemented, which provided almost zero effect of their parasitic capacitances. A methodology has been developed for conducting experimental research on the implementation of four- and three-frequency methods using a mid-range moisture meter and implementing a two-frequency method and a simplified version of it using a very high-frequency moisture meter. Experimental studies on manufactured test emulsions, as well as analysis and processing of their results, were carried out. For all developed multi-frequency methods and moisture values of test emulsions in the range of 10⁻⁴ – 10⁻², the value of the relative extended uncertainty of moisture measurement did not exceed 5.28 %. For the humidity of the test emulsion 10⁻⁵, the value of this uncertainty did not exceed 10.39 % (due to the lack of stability of the frequency of the reference generator frequency Ch 3 - 34, which was used in the research). The developed improved multi-frequency resonance dielectric methods for determining humidity have increased the sensitivity to a level of 10⁻⁵ while minimizing "varietal uncertainty".
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Коробко, Олександр Анатолійович. « Удосконалення резонансного діелькометричного методу контролю та визначення вологості рідких неполярних діелектриків ». Thesis, Національний технічний університет "Харківський політехнічний інститут", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/40783.
Texte intégralRésumé :
Дисертація на здобуття наукового ступеня кандидата технічних наук (доктора філософії) за спеціальністю 05.11.13 "Прилади і методи контролю та визначення складу речовин" (15 – Автоматизація та приладобудування) – Національний технічний університет "Харківський політехнічний інститут".
Мета роботи: удосконалення резонансного діелькометричного методу контролю та визначення вологості рідких неполярних діелектриків задля підвищення його чутливості до рівня 10⁻⁵ з одночасною мінімізацією впливу "сортової невизначеності". Запропоновані та досліджені: спрощена математична модель емульсії на основі моделі штучного діелектрика Кока; нові багаточастотні різновиди резонансного діелькометричного методу; новий тип розподіленого вимірювального перетворювача. Розроблено, теоретично та експериментально досліджено вологоміри середньочастотного та дуже високочастотного діапазонів. Експериментальним шляхом підтверджено досягнення мети роботи.Thesis for a candidate degree (PhD) in specialty 05.11.13 "Instruments and methods of control and determination of substances" (15 – Automation and Instrumentation) − National Technical University "Kharkiv Polytechnic Institute". The thesis is devoted to the improvement of the resonant dielectric method of monitoring and determining the humidity of emulsions such as liquid non-polar dielectric - water in order to increase its sensitivity to level 10⁻⁵ while simultaneously minimizing the type and grade of non-polar dielectric ("varietal uncertainty") on the measurement results. An analytical review and analysis of the existing methods and means of implementation of the dielectric method in general and its resonant variety has been carried out. The main research areas have been identified: development of a simplified emulsion model; development of new varieties of the resonant dielectric method with minimization of the effect of "varietal uncertainty" for measuring humidity at a level of 10⁻⁵; development of a new type of distributed transducer. A simplified emulsion model was chosen based on the Kok artificial dielectric model, its applications were determined by frequency, humidity, and the values of its systematic errors were determined. New multifrequency varieties of the resonant dielectric method have been developed based on the proposed mathematical model of the emulsion, taking into account the parasitic capacitances of the measuring generator and the measuring converter. Metrological characteristics of the generalized four-frequency method and its simplified three-and two-frequency varieties are obtained. The areas of applicability of multifrequency methods are analyzed and their systematic errors are determined. The most sensitive method, the two-frequency method, was determined, the effect of dielectric losses in water was analyzed for it, and the generation frequency of the measuring generator, which corresponds to its maximum sensitivity, 100 MHz, was determined. A new type of distributed-type measuring transducer is proposed for the practical implementation of the two-frequency method — a stepwise heterogeneous coaxial resonator; its theoretical and experimental studies are carried out; its advantages in relation to the known transducers are determined. A hygrometer of the mid-frequency range based on a concentrated-type capacitive transducer and a hydrometer of a very high-frequency range based on a stepped heterogeneous coaxial resonator have been developed. The circuit solutions of the measuring transducer and the measuring generator of the hygrometer of the midfrequency range, which provided the minimum values of their parasitic capacitances, were developed and implemented. The circuit solutions of the measuring transducer and the measuring generator of a hygrometer of a very high frequency range have been developed and implemented, which provided almost zero effect of their parasitic capacitances. A methodology has been developed for conducting experimental research on the implementation of four- and three-frequency methods using a mid-range moisture meter and implementing a two-frequency method and a simplified version of it using a very high-frequency moisture meter. Experimental studies on manufactured test emulsions, as well as analysis and processing of their results, were carried out. For all developed multi-frequency methods and moisture values of test emulsions in the range of 10⁻⁴ – 10⁻², the value of the relative extended uncertainty of moisture measurement did not exceed 5.28 %. For the humidity of the test emulsion 10⁻⁵, the value of this uncertainty did not exceed 10.39 % (due to the lack of stability of the frequency of the reference generator frequency Ch 3 - 34, which was used in the research). The developed improved multi-frequency resonance dielectric methods for determining humidity have increased the sensitivity to a level of 10⁻⁵ while minimizing "varietal uncertainty".
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Marth, Wieland. « Hydrodynamic Diffuse Interface Models for Cell Morphology and Motility ». Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-204651.
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In this thesis, we study mathematical models that describe the morphology of a generalized biological cell in equilibrium or under the influence of external forces. Within these models, the cell is considered as a thermodynamic system, where streaming effects in the cell bulk and the surrounding are coupled with a Helfrich-type model for the cell membrane. The governing evolution equations for the cell given in a continuum formulation are derived using an energy variation approach. Such two-phase flow problems that combine streaming effects with a free boundary problem that accounts for bending and surface tension can be described effectively by a diffuse interface approach. An advantage of the diffuse interface approach is that models for e.g. different biophysical processes can easily be combined. That makes this method suitable to describe complex phenomena such as cell motility and multi-cell dynamics. Within the first model for cell motility, we combine a biological network for GTPases with the hydrodynamic Helfrich-type model. This model allows to account for cell motility driven by membrane protrusion as a result of actin polymerization. Within the second model, we moreover extend the Helfrich-type model by an active gel theory to account for the actin filaments in the cell bulk. Caused by contractile stress within the actin-myosin solution, a spontaneous symmetry breaking event occurs that lead to cell motility. In this thesis, we further study the dynamics of multiple cells which is of wide interest since it reveals rich non-linear behavior. To apply the diffuse interface framework, we introduce several phase field variables to account for several cells that are coupled by a local interaction potential. In a first application, we study white blood cell margination, a biological phenomenon that results from the complex relation between collisions, different mechanical properties and lift forces of red blood cells and white blood cells within the vascular system. Here, it is shown that inertial effects, which can become of relevance in various parts of the cardiovascular system, lead to a decreasing tendency for margination with increasing Reynolds number. Finally, we combine the active polar gel theory and the multi-cell approach that is capable of studying collective migration of cells. This hydrodynamic approach predicts that collective migration emerges spontaneously forming coherently-moving clusters as a result of the mutual alignment of the velocity vectors during inelastic collisions. We further observe that hydrodynamics heavily influence those systems. However, a complete suppression of the onset of collective migration cannot be confirmed. Moreover, we give a brief insight how such highly coupled systems can be treated numerically using finite elements and how the numerical costs can be limited using operator splitting approaches and problem parallelization with OPENMPDiese Dissertation beschäftigt sich mit mathematischen Modellen zur Beschreibung von Gleichgewichts- und dynamischen Zuständen von verallgemeinerten biologischen Zellen. Die Zellen werden dabei als thermodynamisches System aufgefasst, bei dem Strömungseffekte innerhalb und außerhalb der Zelle zusammen mit einem Helfrich-Modell für Zellmembranen kombiniert werden. Schließlich werden durch einen Energie-Variations-Ansatz die Evolutionsgleichungen für die Zelle hergeleitet. Es ergeben sie dabei Mehrphasen-Systeme, die Strömungseffekte mit einem freien Randwertproblem, das zusätzlich physikalischen Einflüssen wie Biegung und Oberflächenspannung unterliegt, vereinen. Um solche Probleme effizient zu lösen, wird in dieser Arbeit die Diffuse-Interface-Methode verwendet. Ein Vorteil dieser Methode ist, dass es sehr einfach möglich ist, Modelle, die verschiedenste Prozesse beschreiben, miteinander zu vereinen. Dies erlaubt es, komplexe biologische Phänomene, wie zum Beispiel Zellmotilität oder auch die kollektive Bewegung von Zellen, zu beschreiben. In den Modellen für Zellmotilität wird ein biologisches Netzwerk-Modell für GTPasen oder auch ein Active-Polar-Gel-Modell, das die Aktinfilamente im Inneren der Zellen als Flüssigkristall auffasst, mit dem Multi-Phasen-Modell kombiniert. Beide Modelle erlauben es, komplexe Vorgänge bei der selbst hervorgerufenen Bewegung von Zellen, wie das Vorantreiben der Zellmembran durch Aktinpolymerisierung oder auch die Kontraktionsbewegung des Zellkörpers durch kontraktile Spannungen innerhalb des Zytoskelets der Zelle, zu verstehen. Weiterhin ist die kollektive Bewegung von vielen Zellen von großem Interesse, da sich hier viele nichtlineare Phänomene zeigen. Um das Diffuse-Interface-Modell für eine Zelle auf die Beschreibung mehrerer Zellen zu übertragen, werden mehrere Phasenfelder eingeführt, die die Zellen jeweils kennzeichnen. Schließlich werden die Zellen durch ein lokales Abstoßungspotential gekoppelt. Das Modell wird angewendet, um White blood cell margination, das die Annäherung von Leukozyten an die Blutgefäßwand bezeichnet, zu verstehen. Dieser Prozess wird dabei bestimmt durch den komplexen Zusammenhang zwischen Kollisionen, den jeweiligen mechanischen Eigenschaften der Zellen, sowie deren Auftriebskraft innerhalb der Adern. Die Simulationen zeigen, dass diese Annäherung sich in bestimmten Gebieten des kardiovaskulären Systems stark vermindert, in denen die Blutströmung das Stokes-Regime verlässt. Schließlich wird das Active-Polar-Gel-Modell mit dem Modell für die kollektive Bewegung vom Zellen kombiniert. Dies macht es möglich, die kollektive Bewegung der Zellen und den Einfluss von Hydrodynamik auf diese Bewegung zu untersuchen. Es zeigt sich dabei, dass der Zustand der kollektiven gerichteten Bewegung sich spontan aus der Neuausrichtung der jeweiligen Zellen durch inelastische Kollisionen ergibt. Obwohl die Hydrodynamik einen großen Einfluss auf solche Systeme hat, deuten die Simulationen nicht daraufhin, dass Hydrodynamik die kollektive Bewegung vollständig unterdrückt. Weiterhin wird in dieser Arbeit gezeigt, wie die stark gekoppelten Systeme numerisch gelöst werden können mit Hilfe der Finiten-Elemente-Methode und wie die Effizienz der Methode gesteigert werden kann durch die Anwendung von Operator-Splitting-Techniken und Problemparallelisierung mittels OPENMP
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Ponnaiyan, Thehazhnan Konguvel Ponnaiyan. « Aspects Critical to Advancing Ionic Liquid Pretreatment Technique as a Viable Approach for Lignocellulosic Biomass Conversion ». University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1471652917.
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BOUDH-HIR, MOHAMED ESSALAH. « Contribution a l'etude theorique de la structure et de la thermodynamique d'un fluide polaire au voisinage d'une surface ». Paris 6, 1987. http://www.theses.fr/1987PA066040.
Texte intégralRésumé :
Le profil position-orientation donne par les approximations type msa, lhnc. . . Est identique a celui des spheres dures. Il est montre que, meme dans ce cas, il existe des orientations privilegiees. Loin de la surface, seul le potentiel image classique subsiste. Au voisinage de celle-ci, le resultat est plus complique et ne peut etre prevu par la theorie classique. Il est montre aussi qu'un potentiel anisotrope faible ( equiv. A kt) suffit pour produire des effets observables sur le plan experimental. Deux approximations ont ete comparees: blip et l'inegalite de gibbs-bogolioubov. Enfin, etude des fonctions de correlation de paire: il est montre que, sur la surface et loin de celle-ci, ces fonctions sont decrites par les potentiels direct et image. Dans la region intermediaire, la solution est plus compliquee
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Bony, Nicaise françois. « Stratégie analytique des tradimédicaments : établissement de profils chromatographiques des métabolites phytochimiques apolaires ». Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00906762.
Texte intégralRésumé :
Les médicaments traditionnels à base de plantes (tradimédicaments) sont très utilisés par les populations africaines. Mais leur qualité est difficile à maîtriser, car ce sont des mélanges complexes de plusieurs drogues végétales ou des préparations à base de drogues végétales d'origine souvent inconnue et/ou très variable. Le profil chromatographique des métabolites phytochimiques constitue un outil important pour l'évaluation de la qualité de ces produits.L'objectif de ce travail est de proposer un protocole de préparation des échantillons et d'établissement de profil par chromatographie liquide et chromatographie en phase gazeuse des métabolites apolaires, pour l'évaluation de la qualité des médicaments traditionnels à base de plantes.La méthodologie est basée sur le traitement chimiométrique des profils chromatographiques des métabolites apolaires issus de différents lots de feuilles de Combretum micranthum et Mitracarpus scaber.Le profilage métabolique s'est effectué par chromatographie liquide sur Carbone Graphite Poreux en milieu non-aqueux et par chromatographie en phase gazeuse à haute température, couplées à la spectrométrie de masse, après extraction au dichlorométhane et élimination de la chlorophylle adsorbée sur charbon actif.L'analyse chimiométrique des données utilisant l'analyse PLS-discriminante avec ou sans correction orthogonale du signal, appliquée aux profils chromatographiques des feuilles de Combretum micranthum et Mitracarpus scaber, a montré de faibles différences entre les lots de chaque drogue végétale, et une différenciation claire des deux drogues végétales.Les deux méthodes d'analyse par chromatographie liquide et chromatographie en phase gazeuse permettent de détecter la plupart des métabolites secondaires apolaires bioactifs ou non déjà identifiés dans les feuilles des deux espèces.
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Požar, Martina. « On the nature of structural fluctuations in complex liquids ». Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS269.
Texte intégralRésumé :
L'analyse de différents types de structuration, présents dans des liquides simples et complexes et leurs mélanges, a été réalisée en utilisant la méthode de la dynamique moléculaire. Les mélanges complexes ont au moins un composant associatif, tel que l'eau, les alcools (mono-ols et diols) et les amines. La structuration supra-moléculaire dans ces mélanges est détectée, décrite, quantifiée et liée aux interactions atome-atome entre les molécules. Ces systèmes ont des fluctuations aux comportements intéressants, comme le montrent les intégrales de Kirkwood-Buff. Leurs fonctions de corrélation se comportent d'une manière complexe, en fonction du composant, de la concentration et de la température. Le pré-pic aux petites valeurs de k dans les facteurs de structure site-site est défini comme une signature de la ségrégation en domaines dans ces mélanges. Une attention particulière est mise sur la structuration à longue portée, ce qui est une nouveauté compte tenu de la majorité des travaux dans le domaine de la physique des liquides. Cette thèse contribue à une meilleure compréhension des structures micro-hétérogènes dans les liquides moléculaires et permet d'établir des liens avec les hétérogénéités structurelles dans la matière molle et de la bio-matièreThe analysis of different types of structuring, present in simple and complex liquids and their mixtures, was done using the method of molecular dynamics. Complex mixtures have at least one associative component, such as water, alcohols (mono-ols and diols) and amines. The supra-molecular structuring in these mixtures is detected, described, quantified and connected with the atom-atom interactions is the molecules. These systems have interesting fluctuation behaviors, as shown through Kirkwood-Buff integrals. Their correlation functions behave in a complex way, depending on the component, concentration and temperature. The pre-peak at small k values in the site-site structure factor is defined as a signature of molecular domains in these mixtures. A special focus is placed on long-range structuring, which is a novelty considering the majority of the work in the field of the physics of liquids. This thesis contributes to a better understanding of micro-heterogeneous structures in molecular liquids, and gives new links to structural heterogeneities in soft and bio-matter
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Okello, Maurice O. « Polar ionic media and stabilized charged species in organic synthesis ionic liquids derived from a biorenewable source, d-fructose, as a possible alternative to conventional organic reaction solvents / ». Diss., Online access via UMI:, 2004. http://wwwlib.umi.com/dissertations/fullcit/3150493.
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Agapov, Alexander. « Decoupling Phenomena in Dynamics of Soft Matter ». University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1321922264.
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YANG, HONG-ZHAN, et 楊洪展. « Molecular dynamics calculation of polar polyatomic molecular liquid ». Thesis, 1991. http://ndltd.ncl.edu.tw/handle/55533260315069145706.
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Lin, Yu-siang, et 林鈺翔. « The Effect of Polar Substituents on Bent-Core Liquid Crystals ». Thesis, 2007. http://ndltd.ncl.edu.tw/handle/69522840976599742204.
Texte intégralRésumé :
碩士國立中央大學
化學研究所
95
It is well known that the stability of the mesophase may be augmented by an increase of the polarity or polarization along the mesogenic core of the molecule. A substantial change of the micro- as well as macro-polarizability in a specific structure or molecule can be easily achieved by the introduction of polar substituent along the preferred molecular direction. The effect of polar substituents in a variety of mesogenic systems has been studied and investigated during the past years. Certain predictions were successfully made in terms of mesomorphic behavior. Previous studies also showed that compounds substituted with polar groups, such as -NO2, -CN, might lead to a higher clearing temperature. This effect was attributed to the conjugative interaction increased between the substituent and the ester moiety. On the other hand, the effect of polar substituents on the mesogenic 1,3,4-oxadiazoles was studied. The mesophase and optical properties of these oxadiazole materials were found to be strongly influenced by the presence of a terminal polar group. N,N’-Bis[1-(4’-alkoxyphenyl)-3oxopropenyl]-2-hydroxypropylenediamines and their Pd2+ complexes were previously prepared and found to exhibit columnar phase (Colh) in this group. However, the mesomorphic behavior of the ligands formed smectic phase due to the shape effect. In this work, a series of the similar structures with a variety of polar substituents, so-called bent-core (BC) mesogen was prepared and studied. All compounds were found mesogenic, and the mesophase was assigned tentatively as banana phases.
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Udo, Motonari, et 宇土基成. « Synthesis and Characterization of New Polar-Substituted Pyridine-Containing Liquid Crystalline Compound ». Thesis, 2000. http://ndltd.ncl.edu.tw/handle/11454637496741421341.
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碩士輔仁大學
化學系
89
This study describes an efficient approach to synthesize pyridine-containing liquid crystalline compounds by using of 4-alkylphenyl magnesium bromide to react with alkyl or aryl N-ethoxycarbonylnicotinium chloride and subsequent oxidation by o-chloranil to give regioselective alkyl or aryl 6-(4-alkylphenyl)nicotinates in a fair yield.
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Tsai, Shao-Ling, et 蔡韶玲. « β-Diketone, Pyrazole and Isoxazole Derivatives with Polar Groups : Liquid Crystalline and Thermodynamic Properties ». Thesis, 2007. http://ndltd.ncl.edu.tw/handle/66543881468988295014.
Texte intégralRésumé :
碩士國立中央大學
化學研究所
95
In this serie, we report the synthesis, characterization and mesomorphic properties of two series of new mesogenic derivatives based on pyrazole and isoxazole structures. All compounds were characterized by 1H, 13C-NMR spectroscopy and elemental analysis. The phase behaviors of these mesogenic compounds were characterized and studied by differential scanning calorimeter (DSC) and polarization optical microscope. In serie one, a new type of mesogenic compounds derived from heterocyclic pyrazole and isoxazole (Iz-Cn) were prepared and studied. All compounds exhibited smectic phases depending on the carbon length attached. Replacing hydrogen atom of pyrazole by methyl group (Mpz-Cn), ethanol group (Epz-Cn) and pyridinal group (Ppz-Cn) were carried out and the mesomorphic behavior studied. In serie two, we designed and characterized a series of asymmetrical of organic molecules Hpz-Cn-OH derived from pyrazole with one side chains. These compounds exhibited smectic phases.
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Chen, Shao-Yu, et 陳劭瑜. « From Pure Component Properties to Calculate Vapor-Liquid Equilibrium of Binary Non-polar Mixtures ». Thesis, 2008. http://ndltd.ncl.edu.tw/handle/8pesde.
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碩士國立臺北科技大學
化學工程研究所
96
The phase behavior of vapor-liquid equilibrium and thermodynamics properties of mixtures are important for distillation separation processes, Pseudocritical rules have been developed which enable the calculation of vapor-liquid equilibrium (VLE) values and thermodynamic properties for nonpolar mixtures for wide ranges of temperatures and pressures. Interaction constants of mixtures are obtained by procedures for the calculation of interaction second virial coefficient with relationships for the Kihara spherical core potential with generalized correlation of Tee、Gotoh and Stewart for nonpolar fluids. For nonpolar mixtures, the Lee-Kesler equation of state is employed with the pseudocrtical constants of the system to determine the fugacities of the components in gaseous and liquid phases. They only input data required for these procedures are the critical temperature and pressure and acentric factor for nonpolar components. The binary nonpolar mixtures bubble pressure calculations were tested. Excellent results are obtained for VLE values, particularly for mixtures containing dissimilar components such as the methane/n-heptane and methane/n-octane systems.
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Harrar, Agnes [Verfasser]. « An ionic liquid as polar phase in low-temperature-stable microemulsions / vorgelegt von Agnes Harrar ». 2011. http://d-nb.info/1010969781/34.
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