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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Uptake and Release Kinetics of Sulfolane by Cattail Plants

Leo, Tiffany 01 December 2008 (has links)
Sulfolane (tetrahydrothiophene 1,1-dioxide, C4H8O2S) is a highly water-soluble, non-ionizable, organic compound used along with diisopropanolamine in the SulfinolTM process to remove hydrogen sulfide from natural gas. Sulfolane has been identified in wetland vegetation near a sour gas processing facility in Alberta, Canada, and extensive uptake of sulfolane by cattails has also been demonstrated in a laboratory environment. Consequently, it has been suggested that plants could play an important role in the natural attenuation of sulfolane in contaminated wetlands. This assumes that the sulfolane is metabolized and/or sequestered in the plant and not released back into the environment during winter dieback. To address the potential release issue, individual cattails (Typha latifolia) were grown hydroponically in 500-mL glass containers containing one of three initial sulfolane concentrations (8, 40, or 200 mg/L) for a specified duration (7 to 28 days). Half the cattails were used to quantify uptake as a function of time and exposure concentration and the other half were used to evaluate the potential release of sulfolane into the hydroponic solution. Non-exposed cattails and non-planted systems containing sulfolane served as controls. The cattails used to evaluate the potential release of sulfolane were frozen directly in their individual containers at the end of the appropriate exposure period. After being frozen for a minimum of 72 hours, the containers were thawed and the amount of sulfolane released was monitored. At the end of the 28-day uptake period, sulfolane leaf tip tissue concentrations as high as 3600, 1050, and 165 mg/kg dry weight were found for the cattails initially exposed to 200, 40, and 8 mg/L sulfolane, respectively. The percentage of sulfolane subsequently released by the cattails after the freeze-thaw treatment declined as a function of the duration exposed. The percentages of sulfolane released measured in the water after 72 hours in addition to the plant tissue extractions were 71%, 54%, 27%, and 12% for the 40 mg/L concentration at 7-, 14-, 21-, and 28-day exposure periods, respectively. Other concentrations showed the same decreasing trend for increasing exposure periods. The declining release as a function of time suggests metabolism and/or sequestration of the sulfolane within the plant. The significant uptake and limited release of sulfolane from mature plants indicate that wetland plants could play an important role in its natural attenuation.
2

Kapalné elektrolyty pro lithno-iontové akumulátory s vyšší požární bezpečností / Liquid Electrolytes for Lithium-Ion Batteries with Enhance Fire Safety

Máca, Josef January 2018 (has links)
Dissertation thesis is focused on study of liquid electrolytes for lithium ion batteries. The electrical and physical properties of aprotic electrolytes are observed. The main goal is to increase the fire safety of the batteries. An anhydrous solvents and there blends was investigated. The common used solvents mixtures and new low flammable solvents were used. The common used solvents were used propylene carbonate, ethylene carbonate and others. The new solvents were sulfolane and dimethyl sulfone. In the second part of the work the phosphor base flame retardants as additive in electrolytes was investigated. The last part deals with ionic liquids and there possible use as electrolyte in lithium ion batteries.
3

Kapalné elektrolyty pro lithno-iontové akumulátory / Liquid electrolytes for lithium-ion accumulators

Štichová, Zuzana January 2011 (has links)
The aim of this master´s thesis was the measurement of electrical conductivity and dynamic viscosity of the electrolytes. Based on these measurements to verify Walden theorem between measured variables. Electrolytes were used on sulfolane base in combination with propylene carbonate and salt. The thesis also deals with the measuring method of dielectric properties of electrical and optical method with a refractometer. The freezing point of combination of sulfolan and propylene carbonate were determined by cryoscopy.
4

Elektrolyty s rozpouštědly typu sulfolanu / Electrolytes based on sulfolan and similar solvents

Máca, Josef January 2011 (has links)
Submitted thesis deal with study of aprotic electrolytes in order to increase the safety for use in lithno – ionts accumulators. Increase of safety is specified by measuring the flash point of each electrolytes, at the same time are evaluated also other parameters important for use in accumulators. For determine the window of temperatures where the electrolytes can work is measured by melting point. The melting point is measured by cryoscopy. From electrical properties is measured specific conductivity of the electrolyte.
5

Aprotické elektrolyty pro lithno-iontové akumulátory s vyšší teplotní stabilitou / Aprotic electrolytes for lithium-ion batteries with higher temperature stability

Bajer, Michal January 2013 (has links)
Master thesis deals with safety of aprotic electrolites used in lithium – ion accumulators. Beside conductivity and viscosity of electrolytes is work focused to flashpoint of electrolytes with flame retardants. In main part of work is shortly explained lithium ion accumulator used materials and fundamentals. Flame retardancy mechanisms and used materials are disscussed too. In practical part work deals with description of used measuring methods and evaluation of gauged data. At least optimal composition of electrolyte with flame retardant is proposed.
6

Gelové polymerní elektrolyty s vyšší požární bezpečností / Gel polymer electrolytes with high fire safety

Musil, Michal January 2010 (has links)
This work deals with preparation of PMMA based gel polymer electrolytes with high fire safety and high ionic conductivity. In the theoretical part of the work GPEs for Li – ion accumulators, fire safety tests, fire retardants are mentioned. Preparation of GPEs, electrical and other properties are described in the experimental part. Furthermore, new possible methods of gel preparation are discussed.
7

Vliv solí na vlastnosti aprotických elektrolytů / The salt influence on aprotic electrolytes

Pojer, Stanislav January 2013 (has links)
This thesis deals with the liquid aprotic electrolytes with solvent on the basis of sulfolane blends with other solvent, in combination with the sodium and lithium salts. In these electrolytes are evaluated their properties due to their use in lithium - ion batteries in terms of safety and electrical properties. For safety risk is measured flashpoint and for electrical properties is measured electrical conductivity for selected samples are intended capacities of double layers.
8

Záporné elektrodové materiály v lithium-iontovém akumulátoru / Compatibility of negative electrode materials at system of lithium-ion battery

Šikuda, Milan January 2015 (has links)
This thesis deals with a study of lithium-ion batteries. It is focused into negative electrode materials and electrolytes. In this thesis is presented synthesis, electrochemical properties, possibilities to improving negative electrode materials as LTO (Lithium Titanate Oxid) and graphite. These electrode materials were investigated with respect to their compatibility at electrolytes with carbonate solvents, Sulfolane and DMF (DiMethylFormamide) in detail. The main aim of this thesis is to characterize electrode materials and electrolyte properties depending on wide range of temperatures and their comparison for the purpose of achievement of the best solution. The thesis is divided into two main parts. The theoretical part of thesis describes composition, process of synthesis and analysis of lithium-ion cell. Practical part contains measuring and evaluating of charge-discharge and irreversible capacity characteristics related to variety of environmental temperatures.
9

Elektrolyty s obsahem retardéru hoření na bázi fosforu / Electrolytes containing a phosphorus-based flame retardant

Pelikán, Ondřej January 2018 (has links)
The diploma thesis is focused on the theoretical knowledge of lithium accumulators. More attention is given to electrolytes and especially to flame retardants, where the types and individual examples of flame retardants are described more detailed. The practical part is focused on the individual laboratory measurement of selected samples of electrolytes with different flame retardants. The measurement results are analyzed in other parts.
10

Aprotické elektrolyty s retardery hoření / Aprotic electrolytes with fire retardant

Hlava, Kamil January 2015 (has links)
This thesis deals with liquid aprotic electrolytes based on sulfolane with added flame retardant. The theoretical part of the thesis explains concepts - mainly aprotic electrolytes, flame retardants, and their practical use. It also discusses lithium - ion accumulators and materials used in them while focusing on the electrolyte function. The practical part of the thesis aims to measure the properties of aprotic electrolytes: their conductivity, potential window and flashpoint. It also contains a review of the measurement results.

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