Thèses sur le sujet « SOLVENT SYSTEMS »
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1
Dakua, Vikas Kumar. « Physico-chemical studies on interactions between ion-solvent, ion-ion and solvent-solvent in aqueous and non-aqueous pure and mixed solvent systems ». Thesis, University of North Bengal, 2008. http://hdl.handle.net/123456789/707.
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Cheng, Chin-Hwa 1957. « Solubility of diuron in complex solvent systems ». Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277194.
Texte intégralRésumé :
The solubility of diuron was determined in binary and ternary cosolvent-water systems. The binary systems were composed of a completely miscible organic solvent (CMOS) and water while the ternary systems incorporate partially miscible organic solvents (PMOS) into the binary systems. Due to the low aqueous solubilities of trichloroethylene and toluene, the PMOS's do not behave as cosolvents and they do not play an important role in altering solubility.
3
Lunkov, Sergey. « Modelling metal complexation in solvent extraction systems ». Thesis, Curtin University, 2013. http://hdl.handle.net/20.500.11937/2018.
Texte intégralRésumé :
This thesis represents a theoretical investigation of synergistic solvent extraction of transition metal ions based on models for the commercial used components, namely LIX63 and Versatic10 acid. Quantum mechanical studies of oxime isomerisation have been conducted in order to understand the thermodynamic and kinetic properties of the syn/anti interconversion of LIX63, which is found to favour an oligomeric form in non-polar solvents.
4
Brindle, David. « Lattice models of amphiphile and solvent mixtures ». Thesis, Sheffield Hallam University, 1991. http://shura.shu.ac.uk/19397/.
Texte intégralRésumé :
Materials based on amphiphilic molecules have a wide range of industrial applications and are of fundamental importance in the structure of many biological systems. Their importance derives from their behaviour as surface-active agents in solubilization applications and because of their ability to form systems with varying degrees of structural order such as micelles, bilayers and liquid crystal phases. The nature of the molecular ordering is of importance both during the processing of these materials and in their final application. A Monte Carlo simulation of a three dimensional lattice model of an amphiphile and solvent mixture has been developed as an extension of earlier work in two dimensions. In the earlier investigation the simulation was carried out with three segment amphiphiles on a two dimensional lattice and cluster size distributions were determined for a range of temperatures, amphiphile concentrations and intermolecular interaction energies. In the current work, a wider range of structures are observed including micelles, bilayers and a vesicle. The structures are studied as a function of temperature, chain length, amphiphile concentration and intermolecular interaction energies. Clusters are characterised according to their shape, size and surface roughness. A detailed temperature-concentration phase diagram is presented for a system with four segment amphiphiles. The phase diagram shows a critical micelle concentration (c.m.c) at low amphiphile concentrations and a transition from a bicontinuous to lamellar region at amphiphile concentrations around 50%. At high amphiphile concentrations, there is some evidence for the formation of a gel. The results obtained question the validity of current models of the c.m.c. The Monte Carlo simulations require extensive computing power and the simulation was carried out on a transputer array, where the parallel architecture allows high speed. The development of a suitable parallel algorithm is discussed. A mean field model of a bilayer is presented which has similar interaction potentials as the Monte Carlo model. The ordering of the bilayer is examined as a function of chain length, bilayer thickness, temperature and inter molecular interaction energies. In this approximation a phase transition to the ordered bilayer is observed.
5
Lesutis, Heather Patrick. « Reaction kinetics in environmentally benign novel solvent systems ». Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/11865.
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Bailie, David S. « Homogeneous oxidation catalysis in multiphasic liquid solvent systems ». Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675950.
Texte intégralRésumé :
Carrying out oxidations on an industrial scale in an environmentally sustainable manner can be challenging with currently available methods. Consequentially, the pharmaceutical industry avoids transformations involving oxidations where possible. Developments over the past few decades have brought catalytic processes to light that can carry out oxidations using simple terminal oxidants, such as O2 and H202• In particular, ligand-promoted Pd(II) complexes have been shown to be capable of oxidising alcohols and olefins to carbonyl compounds, producing water as the principal byproduct. In this thesis, aerobic alcohol oxidations and Wacker-type olefin oxidations are studied, with the aim of minimising Pd catalyst loadings through the stabilisation of the catalyst using ligands. Continuing on from previous work on aerobic alcohol oxidations promoted by the 8-hydroxy-2- quinolinesulfonic acid (HSA) ligand, study of functionalized imines and NHC ligands shows the uniqueness of the HSA ligand in enhancement of the oxidation of 2-octanol to 2-octanone. In [C4mpyrr] [FAP] the HSA complex was seen to deactivate but Pd-black was not seen to form, suggesting that the ionic liquid is stabilising the formation of Pd nanoparticles. Supporting of the HSA complex on a SILP was shown to provide similar catalytic activity as in the bulk phase, but requiring significantly smaller volumes of ionic liquid to function. For the Wacker oxidation of olefins, cationic triflate Pdll-complexes were investigated in weakly coordinating solvents, which were found to be active catalysts in a pressurised 8% O2 in N2 environment but resulted in rapid olefin isomerisation. A Pd(OAc)2/H202,-mediated oxidation system in acetic acid was then developed, promoted by the use of ligands such as 2-(2'-pyridyl)benzoxazole. The catalyst could yield 69% acetophenone from styrene under room temperature conditions in 24 hours. Also, the concept of a thermally phase switchable betainium ionic liquid/H2O solvent was trialed for the simplified recovery of the product and catalyst recycle post-reaction.
7
Payne, Kathryn Elizabeth Ann. « Pigment-dispersant-solvent interactions appropriate to paint systems ». Thesis, London South Bank University, 1998. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267389.
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8
Healy, Mary Rose. « Outer-sphere interactions in metal solvent extraction systems ». Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28712.
Texte intégralRésumé :
This work aims to define the modes of action of a series of metal extraction ligands with particular focus on how these depend on the formation of supramolecular assemblies. Though solvent extraction processes are well established industrially often the understanding, particularly of the metal coordination chemistry, is less so. A greater understanding of a variety of solvent extraction systems can lead to the development of stronger and more specific extractants. Chapter 2 examines the role of inter-ligand interactions in the extraction of copper by phenolic oximes and pyrazoles. Computational methods are used to understand the importance of inter-ligand outer-sphere interactions in square-planar copper complexes. It is shown that functionalisation at different positions on the phenol ring can either stabilise or destabilise the copper complex and it is possible to predict the strength of extractants from DFT calculations. Substitution ortho to the phenolic oxygen in the oximes and pyrazoles can have a major effect of enhancing the strength of extractants by “buttressing” the H-bonding between ligands. However, in the amino-methyl substituted oximes buttressing is so strong that is has an adverse effect on complex formation. Crystal structures are confirmed by both ENDOR EPR spectroscopy and DFT structures. A series of 6-X-4-methyl-2-(5-alkyl-1H-pyrazol-3-yl)- phenols (X = H, OMe, Br and NO2) was synthesised and characterised (X = H, OMe, Br and NO2) and the copper extractant found to be 6-nitro-4-methyl-2-(5-(1,3,5-tri-methyl-pentyl)- 1H-pyrazol-3-yl)-phenol extractants. Computational DFT studies in the gas phase were carried out to calculate the formation energies of analogous phenolic pyrazole copper complexes. The predicted order of these energies followed the same trend shown by experimental solvent extraction studies. Studies also showed that substitution can affect not only complex stability through inter-ligand interactions through hydrogen bonding in the outer-sphere but also the strength of metal-ligand bonds. Chapter 3 looks at synergistic solvent extraction systems: where more than one extractant works together to provide additional strength and selectivity. Combinations of neutral N and O donor ligands with carboxylic, phosphinic and sulfonic acids were studied by solvent extraction, crystallographic and computational methods. Crystal structures and DFT-optimised structures show that ligands and acid form pseudo-tridentate ligands where both the neutral ligand and the deprotonated acid are coordinated directly to the metal centre with inter-ligand hydrogen bonding allowing for a more flexible backbone than a classic tridentate system. Although synergistic extractions systems often utilise carboxylic acids many of the structures show the similarities with systems containing phosphinic acids and it was shown experimentally that some extraction systems show greater synergism with phosphinic than carboxylic acid in the recovery of nickel. Chapter 4 deals with the extraction of molybdenum with commercial phosphinic acid extractant Cyanex 600. The propensity for molybdenum to form oxo clusters in aqueous solutions and the influence pH in both the speciation of the Mo species and extraction conditions contributes to a complex extraction profile. The pH dependence of extraction shows that different mechanisms operate at low (pH < 0) and high (pH > 0) pH. The extraction curve shows a conventional S-curve between pH 0 and 1.5 and slope analysis within this pH range gives a value very close to two but identification of structures which match this profile is complex. Maximum pH extraction is see at ~ pH 1.5. ESMS studies identified very similar species in the organic phase despite the variation seen in the S-curve. A survey of the structures of metal complexes of phosphinate ligands suggests that molybdenum-phosphinate complexes can often form cubane-like structure and negative ion ESMS data supports the concept of cluster formation in the organic phase. A common feature of the spectra are tetra- tri- and bi-metal- oxo species and spectra show a large number of peaks. It is very probable that the extraction of molybdenum(VI) with phosphinic acids is a dynamic system as extraction is influenced by the molybdenum speciation in the aqueous phase which is in turn influenced by both the pH and the molybdenum concentration both of which change over the course of a conventional extraction.
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Cocchi, Giovanni <1984>. « Thermodynamic and mechanical properties of polymer-solvent systems ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5782/1/cocchi_giovanni_tesi.pdf.
Texte intégralRésumé :
This work presents the results of theoretical and experimental characterization of thermodynamic, mechanical and transport properties in polymer solvent systems. The polymer solvent pairs considered ranged to those in which the polymer is rubbery, to those in which the initially glassy polymeric matrix is plasticized by the action of the low molecular weight species. Advanced Equation of State models have been adopted for thermodynamic modeling,along with a rigorous procedure that enables to extend their applicability to the non equilibrium, glassy region. Mass sorption kinetics had been modeled with phenomenological models and with advanced kinetic models.Questo lavoro verte sulla caratterizzazione teorica e sperimentale delle proprietà termodinamiche, meccaniche e di trasporto di sistemi polimero-solvente. In particolare sono stati presi in considerazione sia sistemi polimero-solvente in cui la matrice polimerica si trova allo stato di gomma, che sistemi in cui la matrice polimerica esibisce comportamento vetroso, nonché sistemi nei quali si verifica la transizione vetrosa indotta dall'effetto plasticizzante del solvente. La modellazione termodinamica è stata effettuata utilizzando equazioni di stato avanzate e metodi idonei ad estenderne il campo di utilizzo alla condizione di non equilibrio, propria dello stato vetroso. Cinetiche di assorbimento non Fickiane sono state modellate utilizzando approcci fenomenologici e modelli cinetici avanzati.
10
Cocchi, Giovanni <1984>. « Thermodynamic and mechanical properties of polymer-solvent systems ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5782/.
Texte intégralRésumé :
This work presents the results of theoretical and experimental characterization of thermodynamic, mechanical and transport properties in polymer solvent systems. The polymer solvent pairs considered ranged to those in which the polymer is rubbery, to those in which the initially glassy polymeric matrix is plasticized by the action of the low molecular weight species. Advanced Equation of State models have been adopted for thermodynamic modeling,along with a rigorous procedure that enables to extend their applicability to the non equilibrium, glassy region. Mass sorption kinetics had been modeled with phenomenological models and with advanced kinetic models.Questo lavoro verte sulla caratterizzazione teorica e sperimentale delle proprietà termodinamiche, meccaniche e di trasporto di sistemi polimero-solvente. In particolare sono stati presi in considerazione sia sistemi polimero-solvente in cui la matrice polimerica si trova allo stato di gomma, che sistemi in cui la matrice polimerica esibisce comportamento vetroso, nonché sistemi nei quali si verifica la transizione vetrosa indotta dall'effetto plasticizzante del solvente. La modellazione termodinamica è stata effettuata utilizzando equazioni di stato avanzate e metodi idonei ad estenderne il campo di utilizzo alla condizione di non equilibrio, propria dello stato vetroso. Cinetiche di assorbimento non Fickiane sono state modellate utilizzando approcci fenomenologici e modelli cinetici avanzati.
11
Draucker, Laura Christine. « Novel Solvent Systems for the Development of Sustainable Technology ». Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16188.
Texte intégralRésumé :
Sustainable development in chemical engineering offers technical, industrially relevant solutions to environmental and economic issues. This work focuses on three specific issues; improving solvent selection and reducing costly experimentation, improving catalyst recovery while reducing reaction time, and producing commercial viable biofuels by cost effective pretreatments and valuable side product extractions.
Novel solvent systems are a sustainable solution because they provide the ability to replace costly solvents with cheap, benign, and recyclable systems. Specifically, this work investigated the use of one novel solvent system, Gas Expanded Liquids (GXL).When a solvent is exposed to a gas in which it is miscible at modest pressures and temperatures, the liquid solvent becomes expanded, providing a unique tunable and reversible solvent with properties that can be much different then that of the solvent itself. If you apply this gas to a mixture of two liquids of a solid dissolved in a liquid phase, it can often provide a miscibility switch, aiding in separation, crystallization, and
recovery of products or catalysts. In this work several different applications for organic
solvents expanded with carbon dioxide were studied including miscibility switches for
catalyst recycle, pretreatment of biomass for improved bio-ethanol production, and
extraction of valuable chemicals from lignin waste in the pulp and paper industry. Solid
solubility models to improve solvent selection and predict unique solvent mixtures during
crystallization were also studied. The results reported here show promise for the use of
GXL novel solvent systems and solid solubility models in many sustainable applications.
12
Belhadj, Hamza [Verfasser]. « Solvent isotope effect (D2O) in photocatalytic systems / Hamza Belhadj ». Hannover : Technische Informationsbibliothek (TIB), 2017. http://d-nb.info/1150536683/34.
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Chen, Zhihong. « Morphology of, and solvent diffusion in, hollow nanoparticle systems ». Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/5019/.
Texte intégralRésumé :
In this project, we studied the morphology of SiO2/TiO2 hollow nanoparticles (HNPs), the morphology of polymer-embedded HNPs and diffusion of solvents into polymer-embedded HNPs, mainly based on small angle scattering methods. The average outer diameter, average inner diameter and polydispersity of HNPs were characterized by a combination of experimental methods, including light, X-ray and neutron scattering, electron microscopy and N2 adsorption-desorption isotherms. Furthermore, the porosity of the shells of HNPs and the size of intrawall pores were determined by a new method proposed with the combination of the above techniques. Three kinds of polymer-embedded HNP systems were prepared by freeze drying technique, i.e. poly(ethylene oxide) (PEO)-embedded HNPs, poly(methyl methacrylate) (PMMA)-embedded HNPs and polyethylene (PE)-embedded HNPs. The morphology of polymer-embedded HNP systems was investigated by SAXS and electron microscopy. A multi-shell sphere model was proposed to analyze the experimental SAXS data. For PEO-embedded HNPs, HNPs were observed to be supported on porous PEO scaffold. Moreover, it was found that nearly 96% of HNPs were buried uniformly in the PEO matrix, with a thin porous PEO layer deposited on the inner surface of HNP. However, the analysis for the morphology of PMMA-embedded HNPs and PE-embedded HNPs with current SAXS model was hindered due to the aggregation of HNPs. Diffusion of solvents into polymer-embedded HNP systems was monitored by in-situ SAXS. Complex SAXS models were further proposed to obtain the diffusion kinetics. Diffusion of liquid low molecular PEO in PEO-embedded HNPs was found to consist of three stages, i.e. induction stage, steady state stage and depletion stage. It was further found that the filling rate of HNPs by solvent in the steady state stage was about 3 times faster than that in the induction stage and about 90 times faster than that in the depletion stage. Diffusion of water in PMMA-embedded HNPs and diffusion of oleyl alcohol and tetrafluorobenzene in PE-embedded HNPs were found to consist of a fast process and a slow process, which correspond to the relatively fast wetting of the polymer surface and the slow diffusion of solvents in the polymer matrix, respectively.
14
Dreimann, Jens M. [Verfasser]. « Process Intensification in Homogeneous Catalysis - Catalyst Recovery via Thermomorphic Solvent Systems and Organic Solvent Nanofiltration / Jens M. Dreimann ». München : Verlag Dr. Hut, 2017. http://d-nb.info/1139538349/34.
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Dreimann, Jens [Verfasser]. « Process Intensification in Homogeneous Catalysis - Catalyst Recovery via Thermomorphic Solvent Systems and Organic Solvent Nanofiltration / Jens M. Dreimann ». München : Verlag Dr. Hut, 2017. http://d-nb.info/1139538349/34.
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Hamilton, Patrick Neal. « The behavior and separation of polystyrene in mixed solvent systems ». [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1256.
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Baranowski, Roman. « The properties of polymer/solvent systems at surfaces and interfaces ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq25767.pdf.
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Pitt, Julian Llewellyn. « The behaviour of mineral particles in uranium solvent extraction systems ». Thesis, Imperial College London, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339619.
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Rivett, Carl Matthew. « Carbon Dioxide as a Solvent and Antisolvent for Hydrocarbon Systems ». Thesis, University of East Anglia, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.518387.
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Helal, Hatem Hamdi Ahmed. « Including solvent effects in first-principles simulations of biological systems : development, implementation, and application of an implicit solvent model ». Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609182.
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Husain, Zainul Abideen. « Coupling reactions and separations in propane-organic-aqueous tunable solvent systems ». Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29719.
Texte intégralRésumé :
Thesis (M. S.)--Chemical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Eckert, Charles; Committee Co-Chair: Liotta, Charles; Committee Member: Meredith, Carson. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Hafner, Kellye Padgett. « Design of solvent systems for supercritical fluid and high pressure applications ». Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/11211.
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Theaker, Ian. « A structural and thermodynamic study of non-aqueous solvent/wax systems ». Thesis, University of Hull, 1996. http://hydra.hull.ac.uk/resources/hull:4996.
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Non-aqueous wax/solvent systems of industrial relevance for the manufacture of paste polishes have been investigated. These mixtures have been modelled using a paraffin wax of Japanese origin (Nippon Seiro 140/145°F) in a solution of pure heptane to which dopant components are added.The stability of any resulting gel has been assessed via solubility studies and measurement of the solvent vapour pressure. A new technique for the measurement of vapour pressure in these systems has been developed. The operation of the apparatus has been made almost completely automatic by the use of modern control units.Complementary analytical techniques such as Differential Scanning Calorimetry and Nuclear Magnetic Resonance have been used to augment the data where appropriate and the structure of these pastes has been investigated with the use of Optical Microscopy.
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Chavez, Krystle J. « Crystallization of pseudopolymorphic forms of sodium naproxen in mixed solvent systems ». Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29759.
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Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Rousseau, Ronald; Committee Member: Meredith, Carson; Committee Member: Prausnitz, Mark; Committee Member: Teja, Amyn; Committee Member: Wilkinson, Angus. Part of the SMARTech Electronic Thesis and Dissertation Collection.
25
Das, Mousumi. « Physico-chemical investigation of transport and thermodynamic properties of some electrolytes in verious solvent systems ». Thesis, University of North Bengal, 2007. http://hdl.handle.net/123456789/817.
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Eckert, Norbert L. « Aspects of phase separation in an experimental mixer-settler using two solvent extraction systems ». Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26697.
Texte intégralRésumé :
An experimental investigation was undertaken to study the factors affecting phase separation in a specially constructed, laboratory scale mixer-settler. Two phase systems were used:
1. A laboratory prepared HSLIX64N-copper phase system, similar to that used in commercial copper solvent extraction processes.
2. A phase system obtained directly from the uranium extraction circuit of the Key Lake Mining Corporation, Sask., millsite.
A settler scale-up criterion relating dispersion band thickness to specific settler flow of dispersed phase, was found to have considerable merit. Besides being dependent on specific settler flow, the dispersion band thickness was found to be a function of the phase ratio (for system 2 only), dispersion introduction level (for system 2 only), and temperature. Mixing intensity had no appreciable effect with either system.
Microscopic examination of the dispersion produced with system 2 revealed the existence of double dispersions; that is, drops within drops.
A photomicroscopic technique was used to undertake a drop size investigation of the dispersion produced with system 2. Drop size was found to be independent of dispersion throughput, a weak function of impellor speed and a relatively strong function of the phase ratio.
With the exception of organic continuous operation with system 1, it was possible, based on the holdup and drop size profile within the dispersion band, to distinguish two horizontal sublayers within the dispersion band. In the "even concentration sublayer", comprising the majority of the dispersion band, the holdup and average drop size is nearly constant throughout. In the "dense concentration sublayer", both the holdup and the average drop size increase sharply as the coalescence front is approached.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Rieck, Daniel C. « MEMS fabricated nanopores and micropores functionalized with chromate-selective solvent polymeric membrane ». Pullman, Wash. : Washington State University, 2008. http://www.dissertations.wsu.edu/Thesis/Fall2008/d_rieck_012609.pdf.
Texte intégralRésumé :
Thesis (M.S. in chemical engineering)--Washington State University, December 2008.Title from PDF title page (viewed on Apr. 10, 2009). "Department of Chemical Engineering." Includes bibliographical references.
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Cecconie, Theodore James 1961. « Fundamental studies on the separation of the lanthanides using solvent extraction systems ». Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276744.
Texte intégralRésumé :
Fundamental solvent extraction studies on the separation of the lanthanides were carried out by investigating both the hydroxamic acid and phosphinic acid reagent families. In general, the lanthanides were found to extract as self-adducts. It was found that the separation of the individual lanthanides with both of these reagent families was adversely affected by steric hindrance.
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Muhuri, Prakash Kumar. « Studies on the ion-solvent interactions of some electrolytes in propylene carbonate and its binary mixtures with other organic solvent systems ». Thesis, University of North Bengal, 1993. http://hdl.handle.net/123456789/710.
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Sinha, Anuradha. « Investigation on viscous synergy and antagonism of some liquid mixtures and ion-solvent interaction of some compounds in various solvent systems ». Thesis, University of North Bengal, 2006. http://hdl.handle.net/123456789/705.
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Brunet, Jean-Christophe. « An expert system for solvent-based separation process synthesis ». Thesis, Virginia Tech, 1992. http://hdl.handle.net/10919/42949.
Texte intégralRésumé :
Expert systems are being used more daily in chemical engineering. This work continues the development of an EXpert system for SEParation flowsheet synthesis named EXSEP. Written in Prolog, it can generate flowsheets for four multicomponent separations: distillation, absorption, stripping and liquid-liquid extraction. For these separations, we describe a large collection of heuristics (or rules) that are used for flowsheet synthesis. EXSEP uses several of these heuristics and the Kremser equation to test the thermodynamic feasibility of separation tasks. EXSEP requires only basic input data such as the expected component flow rates in each product and the component K-values. With those data, EXSEP searches for the sets of the number of theoretical stages, solvent flow rate, and component-recovery ratios that characterize a number of feasible and economical flowsheets. The use of the component assignment matrix (CAM) combined with Prolog list processing makes EXSEP very fast (several seconds) to generate solutions. We test EXSEP with several examples of industrial separation processes and compare the results with the literature. We also compare EXSEP results with rigorous simulations using commercial CAD software (e.g., DESIGN II). In most cases, EXSEP gives very similar and even better flowsheets. However, EXSEP is limited to dilute solvent-based separations and cannot solve problems where the major feed component is also the solvent (e.g. sour-water steam stripper). The development of EXSEP on IBM-PC makes it very "user friendly". In the future, EXSEP should be expanded with additional modules such as extractive and azeotropic distillation, and bulk absorption. It should also include modules for separation method and solvent selections, which are great challenges in flowsheet synthesis.Master of Science
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Horne, Gregory. « An experimental and computational investigation into the radiolysis of PUREX solvent systems ». Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/an-experimental-and-computational-investigation-into-the-radiolysis-of-purex-solvent-systems(a793f6ee-0b49-47ce-ae2b-cd88d94c53a0).html.
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Plutonium Uranium Reduction EXtraction (PUREX) technology is a solvent extraction process used to recover plutonium and uranium from spent nuclear fuel. The solvent system is composed of an aqueous nitric acid phase in contact with an organic phase made up of tributyl phosphate in an organic diluent. During the separation process, the PUREX solvent system is subject to an intense multi-component radiation field (gamma rays, alpha particles, beta particles, neutrons, and fission fragments) rendering it susceptible to radiolytic degradation, which reduces its performance. Despite the PUREX process being used for over sixty years, a complete quantitative mechanistic understanding of the radiolytic degradation processes is not available. Nitrous acid is the most significant radiolytic degradation product of nitric acid, especially as its chemical and physical properties alter the formulation of the PUREX solvent system. Furthermore, nitrous acid exhibits complex redox relationships with a number of actinides, with plutonium being of greatest concern to the performance of the PUREX process. A combination of experimental and computational (stochastic and deterministic) techniques have been used to investigate the radiolysis of the PUREX solvent system's aqueous phase, specifically the radiolytic formation of nitrous acid, and its conjugate base nitrite, as a function of solvent system formulation, absorbed dose (up to 1.7 kGy), and radiation quality (cobalt-60 gamma rays and alpha particles from plutonium and americium alpha decay). The research presented in this thesis focuses on: (i) the experimental radiation chemistry of solutions of nitric acid and sodium nitrate over the range of concentrations 1 × 10-3 to 6 mol dm-3, and (ii) the development of a multi-scale modelling approach for evaluating the radiolysis of aqueous systems in terms of reaction mechanisms. The experimental and modelling studies provide insight into the radiation chemistry of the PUREX solvent system's aqueous phase, mechanistically demonstrating how the radiation chemical yield of nitrous acid and nitrite is dependent upon the interplay between non-homogeneous radiation track chemistry and secondary bulk homogeneous chemistry. This interplay is influenced by low pH, the presence of chemical scavengers and redox active metal ions, and radiation quality. These findings will act as a benchmark for the development of advanced reprocessing schemes, which must seriously consider how modifications in solvent system formulation and fuel composition may affect this dynamic interplay, and ultimately the generation of secondary highly active liquid waste.
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Tian, Olivia Yingnan. « Pigmented and solvent dyed latex systems for ink jet printing on textiles ». Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/8681.
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Nzengung, Valentine Asongu. « Organoclays as sorbents for organic contaminants in aqueous and mixed-solvent systems ». Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/26460.
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McGillen, J. G. « Studies on the wet spinning of cellulose fibres from novel solvent systems ». Thesis, University of Strathclyde, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372448.
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Gumus, Selahaddin. « Secondary Electronic and Solvent Effects on Regiospecific P-Bromination of Aromatic Systems ». TopSCHOLAR®, 2018. https://digitalcommons.wku.edu/theses/3031.
Texte intégralRésumé :
Bromoarenes are important aromatic building blocks that are commonly used to synthesize various functional compounds in pharmaceutical, agrochemical and related industries.1,2 This great demand for bromoarenes makes their preparation a widely studied area of synthetic organic chemistry. However, further understanding of the reactivity and regiochemistry of aromatic functionalization reactions is still necessary, as much about the secondary substitution and solvent effects remain unknown.
Resonance Theory is a widely used theoretical model to predict the regiospecifity and reactivity of the bromination of various aromatic compounds.3 The reactivity and regiospecificity of many substituted aromatic compounds is well explained using resonance theory.4 However, kinetic understanding of the p-bromination of halosubstituted aromatic compounds has not been investigated to the best of our knowledge.5,6In this thesis, the reactivity and regiospecifity of the p-bromination of activated secondary substituted aromatic compounds as well as media effects on the process will be discussed.
Synthesizing bromoarenes has been accomplished using many different experimental setups.7-11 N-bromosuccinimide is the most highly utilized electrophilic aromatic brominating agent. Many of the NBS- based aromatic bromination reactions have been reported using strong acids, strong bases, halogenated solvents, nonpolar solvents and polar solvents alike.12 The bromination reactions reported herein were performed using two different solvents, acetonitrile and acetone, to investigate the effects of solvent polarity on p-bromination. Although acetonitrile is one of the most commonly used solvents in the p-bromination of aromatic compounds, acetone has not been investigated.
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APRAHAMIAN, EDWARD JR. « ROLE OF THE INTERFACE IN THE KINETICS AND MECHANISM OF SOLVENT EXTRACTION SYSTEMS (DITHIZONE, OXINE, INTERFACIAL AREA, DISPERSION) ». Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187968.
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A high speed stirring apparatus was constructed for following the kinetics of metal ion extraction by chelating agents. The semi-automated system is capable of measuring reactions with half lives of 20 seconds or more with data being collected every second. Experimental data obtained with the device are superior to those collected by batch shakers, fixed interface cells, falling drop, or other stirring devices. The use of a microporous Teflon membrane phase separator along with the thermodynamic relation, the Gibbs Equation, enabled the measurement of drop sizes in a two phase liquid-liquid dispersion. This allowed the determination of the quantity of interfacial area as a function of stir rate. The effect of interfacial area on the rate of extraction of five different chelating agents with various divalent metal ions was determined in this study. The role of the interfacial area in extraction kinetics was found in a system where diffusional effects are negligible. This information provides an answer to the question of whether the rate determining step of extraction occurs in either the bulk aqueous phase or in the interfacial region. The proportionality between rate and specific interfacial area was employed to find the magnitude of the contributions of the bulk and interfacial components and also allowed the calculation of the individual rate constants. Evaluation of the bulk and interfacial rate constants yields important fundamental information as to the chemical nature and differences between the chloroform/water interface and the bulk aqueous phase. The results appear to illustrate that the interface is a more conducive medium for reaction between metal and ligand than the aqueous phase. The role of foreign species, namely nonionic surfactants, on the rate of extraction was investigated to explore their applicability in solvent extraction. Nonionic surfactants were found to enhance the rates of extraction to different extents in different metal systems.
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Khalid, Muhammad. « Influence of solvent viscosity, polarity and polarizability on the chemiluminescence parameters of inter and intramolecular electron transfer initiated chemiexcitation systems ». Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-29092015-114251/.
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The cyclic peroxides: diphenoyl peroxide (1), spiro-adamantyl-1,2-dioxetanone (2) and 4-(3-tert-butyldimethylsilyloxyphenyl)-4-methoxyspiro[1.2-dioxetane-3.2\'-adamantane] (3) synthesized, purified and characterized, also their kinetic and chemiluminescence (CL) properties were determined. The influence of solvent polarity on the chemiexcitation parameters of the catalyzed decomposition of 1 and 2, as well as the induced decomposition of 3 were examined in several binary solvent mixtures with different polarity and polarizability parameters, but similar viscosities. For solvents with low polarity, singlet quantum yields for the intermolecular catalyzed decomposition of diphenoyl peroxide (1,) and 1,2-dioxetanone (2) increase in function of medium polarity, showing maximum values in mediums of intermediate polarity, and decreasing in highly polar mixtures. For the induced decomposition of 3, the quantum yield showed to increase with increasing solvent polarity, including high polar solvent systems. In the binary solvent systems studied, the polarizability parameter showed to be contrary to the polarity values, therefore, it might appear that an increase of polarizability leads to a decrease in the singlet quantum yields for catalyzed decomposition of diphenoyl peroxide (1) and the induced decomposition of 3, however an increase in the singlet quantum yields for 1,2-dioxetanone 2. The three CL systems were also studied in binary solvent mixtures with different viscosities but similar polarity and polarizability parameters and singlet quantum yields showed an increase with increasing medium viscosity. Data were analyzed by using the collisional and the free volume models. The highly efficient intramolecular system induced 1,2-dioxetane 3 decomposition showed to be much more sensible to viscosity effects than the inefficient intermolecular systems. This surprising fact indicates that, even showing a significant solvent-cage effect, the induced 1,2-dioxetane should occur by an intramolecular electron back transfer. Moreover, chemiluminescence parameters of these systems were studied in several pure solvents. The obtained singlet quantum yields were correlated with viscosity, polarizability and polarity parameters by using multiple linear regression analysis.Os peróxidos cíclicos: peróxido de difenoila (1), spiro-adamantil-1,2-dioxetanona (2) e 4-(3-terc-butildimetilsililoxifenil)-4-metoxispiro[1,2-dioxetano-3.2\'-adamantano] (3) foram sintetizados, purificados e caracterizados e as suas propriedades cinéticas e de quimiluminescência (CL) determinadas. A influência da polaridade do solvente sobre os parâmetros de quimi-excitação da decomposição catalisada de 1 e 2, e a decomposição induzida de 3 foi examinada em diversas misturas binárias de solventes com parâmetros de polaridade e polarizabilidade diferente, mas viscosidades semelhantes. Para solventes com baixa polaridade, os rendimentos quânticos singlete para a decomposição catalisada intermolecular do peróxido de difenoila (1) e 1,2-dioxetanona (2) aumentam em função da polaridade do meio, mostrando valores máximos em meios com polaridade intermediária, e diminuim para misturas altamente polares. Para a decomposição induzida de 3, o rendimento quântico mostrou aumentar com o aumento da polaridade do solvente, inclusive para sistemas com alta polaridade. Nos sistemas binários de solventes estudados, os parâmetros de polarizabilidade mostraram-se contrários aos valores de polaridade, portanto, parece que um aumento da polarizability leva a uma diminuição nos rendimentos quânticos singlete para a decomposição catalisada do peróxido de difenoila (1) e a decomposição induzida de 3, no entanto, um aumento nos rendimentos quânticos singlete para a 1,2-dioxetanona 2. Os três sistemas de CL também foram estudados em misturas binárias de solventes com diferentes viscosidades, mas com parâmetros de polaridade e polarizabilidade semelhantes e os rendimentos quânticos singlete mostraram aumentar com o aumento da viscosidade do meio. Os dados foram analisados usando tanto o modelos colisional quando o modelo de volume livre. Surpreendentemente, o sistema altamente eficiente decomposição induzida intramolecular do 1,2-dioxetano 3 mostrou-se muito mais sensível aos efeitos da viscosidade do que os sistemas intermoleculares ineficientes, o que indica claramente que a decomposição induzida do 1,2-dioxetano deve ocorrer por um processo de retro-transferência de elétron intramolecular. Além disso, os parâmetros de quimiluminescência destes sistemas foram estudados em vários solventes puros. Os rendimentos quânticos singlete obtidos foram correlacionados com parâmetros de viscosidade, polarizabilidade e polaridade usando análise de regressão linear múltipla.
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Cikalo, Maria Gillian. « Separation and quantification of weakly-absorbing and low-concentration analytes by capillary electrophoresis ». Thesis, University of York, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321675.
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Datta, Biswajit. « Exploration of miscellaneous interfaces of some ionic solids and ionic liquids Prevailing in various solvent systems by the process of psysicochemical contrivance ». Thesis, University of North Bengal, 2017. http://ir.nbu.ac.in/handle/123456789/2673.
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Chunsrivirot, Surasak. « Binding affinity of a small molecule to an amorphous polymer in a solvent ». Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65771.
Texte intégralRésumé :
Thesis (Ph. D.)--Massachusetts Institute of Technology, Computational and Systems Biology Program, 2011.Page 169 blank. Cataloged from PDF version of thesis.
Includes bibliographical references (p. 165-168).
Crystallization is a commonly used purification process in industrial practice. It usually begins with heterogeneous nucleation on a foreign surface. The complicated mechanism of heterogeneous nucleation is not well understood, but we hypothesize a possible correlation between binding affinity to a surface and nucleation enhancement. Amorphous polymers have been used in controlling crystallization. However, to our knowledge no attempt has been made to investigate the possibility of using binding affinity to help guide the selection of polymers promoting heterogeneous nucleation. This study investigated the possibility of using binding affinity of one molecule and many molecules to help guide the selection of these polymers. To measure the binding affinity of one molecule, we developed a two-step approach to compute the free energy of binding to a binding site, using a system of ethylene glycol, polyvinyl alcohol (PVA), and heavy water (D20). The first step of our approach uses Adsorption Locator to identify probable binding sites and molecular dynamics to screen for the best binding sites. The second step employs the Blue-Moon Ensemble method to compute the free energy of binding. We then applied our procedure to the systems of aspirin binding on the surfaces of four nonporous crosslinked polymers in ethanol-water 38 v%. These polymers are poly(4- acryloylmorpholine) (PAM), poly(2-carboxyethyl acrylate) (PCEA), poly(4-hydroxylbutyl acrylate) (PHBA), and polystyrene (PS), and they all are crosslinked with divinylbenzene (DVB). We developed an approach to construct these crosslinked polymers and built three independent surfaces for each polymer. We found the similarity between the trend of heterogeneous nucleation activity and that of the average free energies of binding to the best site of each polymer surface. To measure the binding affinity of many molecules, preferential interaction coefficient and the number of aspirin molecules associated with the area of the binding site was calculated. We found that there is also a similarity between the trend of heterogeneous nucleation activity and that of number of aspirin molecules associated with the area of the binding site (taken into account the effects of polar/apolar atom interactions between an aspirin and a polymer). These results suggest the possibility of using binding affinity, especially the free energy of binding to the best site and the number of nucleating molecule, to help guide the selection of polymers promoting heterogeneous nucleation.
by Surasak Chunsrivirot.
Ph.D.
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Julien, Grégoire. « Dynamics in polymer blends and polymer-solvent blends close to the glass transition ». Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10187/document.
Texte intégralRésumé :
Dans ce travail, nous proposons un modèle qui décrit la dynamique dans les mélanges de polymères et polymère-solvant à l'approche de la transition vitreuse. Le modèle est résolu sur un réseau 2D sur des échelles de 10 nm à plusieurs microns. Ce modèle incorpore l'aspect hétérogène de la dynamique à l'échelle d'une hétérogénéité dynamique (3-5 nm). Dans le cas des mélanges de polymères, nous appliquons ce modèle afin d'étudier la séparation de phase lorsque le système est refroidi proche ou sous Tg, et le rajeunissement lorsque le système est réchauffé dans un état miscible et fondu. Pendant la séparation de phase, nous observons que des morphologies lentes se forment en coexistence avec des morphologies rapides. Pendant ce temps, la dynamique globale du système se ralentit et les domaines croissent comme le logarithme du temps. Lors de la réchauffe en revanche, nous observons que les domaines vitreux fondent plus vite que le temps nécessaire pour qu'ils se forment lors de la séparation de phase. Dans le cas des mélanges polymère-solvant, le système est en contact avec un réservoir de solvant et est en dessous de la température de transition vitreuse du polymère pur. L'activité du réservoir peut être changée afin de décrire le séchage ou le gonflement de films. Notre modèle permet de décrire la diffusion cas-II lorsqu'un polymère vitreux est plastifié par du solvant qui pénètre le système. Concernant le processus inverse de séchage, nous montrons que des films ayant des épaisseurs inférieures à 1 micron peuvent être séchés entièrement. Pour des films plus épais, en revanche, une croûte vitreuse se forme sur la surface libre du filmIn this work, we propose a model for describing the dynamics in polymer blends or polymer-solvent blends close to and below Tg. The model is solved on a 2D lattice corresponding to spatial scales from 10 nm up to a few micrometers and incorporate the heterogeneous nature of the dynamics at the scale of a dynamic heterogeneity (3-5 nm). In case of polymer blends, we apply this model to study phase separation close to and below Tg upon cooling, and rejuvenation in miscible range upon heating. In the course of phase separation, we observe slow structures forming in coexistence with faster ones. In the same time, the global dynamics of the system slows down and domains grow like the logarithm of the time. During rejuvenation, we observe that morphologies melt much faster the elapsed time required to build them during aging. In the case of polymer-solvent blends, the system is put in contact with a solvent reservoir and is at temperatures far below the pure polymer glass transition. We consider situations where the activity of the solvent reservoir is varied in order to describe either films drying or swelling. Our model allows for explaining case-II diffusion in the context of the plasticisation of a glassy polymer by penetrating solvent during swelling. Regarding the process of film drying, we show that films up to 1 micrometer thick can be completely dried. When drying a thicker film, we show that a glassy crust may appear on the free surface, as shown experimentally
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Das, Bijan. « Physico - chemical investigations on the ion-solvent interactions of some Tetraalkylammonium and common ions in non-aqueous and mixed binary aqueous solvent systems ». Thesis, University of North Bengal, 1992. http://hdl.handle.net/123456789/719.
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Adinata, Donni [Verfasser]. « Single-drop based modelling of solvent extraction in high-viscosity systems / Donni Adinata ». Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2011. http://d-nb.info/1018200606/34.
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Chang, Yun Chea. « Concentration dependent diffusion of solid-solute, liquid-solvent systems in the supersautrated region ». Diss., Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/11802.
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Gautam, Devaki Nandan. « Molecular dynamics simulation of horse-heart cytochrome c in water-methanol solvent systems ». Thesis, Wichita State University, 2014. http://hdl.handle.net/10057/10956.
Texte intégralRésumé :
Molecular Dynamics simulations have been carried out to investigate the dynamics of horse heart Cytochrome C and associated crystallographic water molecules in different water-methanol systems. The 100 ns simulation predicts that hh-CytC undergoes different dynamical transitions with some common conformations in different solvents. With increase of methanol concentration in solvents, hh-CytC has increased flexibility, fluctuating its hydrophobic solvent accessible surface area (SASA), and number of persistent internal hydrogen bonds with long hydrogen-bond-lifetime. The protein became more liquid-like in mixed solvents compared to pure solvents; flexibility increases in the absence of the crystallographic water. Similarly, the number of hydrogen bonds between solvent molecules and hh-CytC decreased with increasing of methanol concentration. Water-protein and methanol-protein hydrogen bond lifetimes were computed 11.5 and 16.6 picoseconds, respectively, in pure solvents. However, in mixtures, solvent-protein hydrogen bond lifetime was higher in twenty percent methanol than in fourty percent in water. The surface crystallographic water molecules diffused easily in bulk solvents within 1 nanosecond and protein surface is stabilized by hydrogen bonds with a solvation layer. The two crystallographic water molecules which are buried internally in hh-CytC have 5 to more than 100 nanoseconds residence time in the conserved sites with 100's of picoseconds of hydrogen bond lifetime depending on the solvent compositions. The residence time might depend on the mechanism of conformational transition of protein in simulation. Solvent water molecules exchange these buried water molecules but exchange is less frequent than that in hydration layer. Even though methanol has succeeded to reside into these conserved sites in pure methanol solvent but its distance with hydrogen bonding partners more than 5 A with labile hydrogen bonding state.Thesis (M.S.)--Wichita State University, Fairmount College of Liberal Arts, Dept. of Chemistry
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Van, Deventer David. « Discrimination of Retained Solvent Levels in Printed Food-Packaging Using Electronic Nose Systems ». Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/9741.
Texte intégralRésumé :
The expanding role of electronic nose instrumentation, as a quality-monitoring tool for food-packaging materials, is examined and reviewed. The food industry is interested in determining the applicability of using an electronic nose for odor analysis of retained printing solvent levels in packaging. Three electronic nose systems were optimized for this application and their performance assessed. These include the FOX 3000, the Cyranose 320, and the QMB6.
Response surface methodology was used to generate 2nd order models of sensor response as a function of system and experimental parameters for the three electronic nose systems. Forty-seven of 50 sensor models generated were found to be significant at an a-level of 0.05. Optimum settings, that allowed adequate signals to be obtained for the full range of examined retained solvents levels, were selected for the remaining work using these models.
Performance analyses of these systems, which use three leading sensor technologies, showed that the conducting polymer sensor technology demonstrated the most discriminatory power. All three technologies proved able to discriminate among different levels of retained solvents. Each complete electronic nose system was also able to discriminate between assorted packaging having either conforming or non-conforming levels of retained solvents. Each system correctly identified 100% of unknown samples. Sensor technology had a greater effect on performance than the number of sensors used. Based on discriminatory power and practical features, the FOX 3000 and the Cyranose 320 were superior. The results indicate that electronic nose instrumentation can be used as a complimentary discriminatory tool in quality control.Master of Science
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Lin, Tingdong. « On the phase behavior and particle formation in polyimide/solvent/nonsolvent ternary systems ». Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06062008-165916/.
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Eser, Hülya Tıhmınlıoğlu Funda. « Diffusion And Equilibrium Measurements In Polymer-Solvent Systems By Inverse Gas Chromatography Method/ ». [s.l.] : [s.n.], 2004. http://library.iyte.edu.tr/tezler/master/kimya/T000451.pdf.
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Kobayashi, Takashi. « Development of Reactor Systems Based on Kinetic Analysis of β-Glucosidase-or Lipase-catalyzed Condensation in Organic Solvent Systems ». Kyoto University, 2003. http://hdl.handle.net/2433/148961.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第10232号
農博第1304号
新制||農||862(附属図書館)
学位論文||H15||N3753(農学部図書室)
UT51-2003-H653
京都大学大学院農学研究科応用生命科学専攻
(主査)教授 松野 隆一, 教授 大東 肇, 教授 井上 國世
学位規則第4条第1項該当