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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

Dioxan in histochemistry a comparative study of the alcohol+chloroform and dioxan technics.

Gupta, Kailash C. January 1964 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1964. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 32-35).
2

1,4-Dioxane Remediation Using a Constructed Wetland

Ward, William Jackson January 2008 (has links)
This research addressed the question whether a constructed wetland system with phytoremediation could successfully uptake 1,4-Dioxane in groundwater and secondary effluent. It further addressed whether open pond storage could successfully treat wetland discharge. The project was located at the University of Arizona's Constructed Ecosystems Research Facility (CERF) in Tucson, Arizona. This two-year field study was motivated by previous laboratory studies which demonstrated the capability of plants to remediate the recalcitrant contaminant 1,4-Dioxane.The study was conducted in two open steel tanks configured to simulate constructed wetlands. The efficacy of 1,4-Dioxane uptake by cottonwood trees was tested in a side-by-side comparison utilizing planted and unplanted tanks. The sub-surface hydraulic conditions were fully characterized by bromide tracer studies. Six experiments were conducted, in which tapwater or secondary effluent was spiked with 5.2 mg/L 1,4-Dioxane and fed to the planted and unplanted (control) tank. The tank discharges were retained in separate open ponds to test if open pond storage would reduce 1,4-Dioxane content. Additional side experiments were conducted to examine the role of volatilization and UV degradation. Comparison of 1,4-Dioxane mass discharge from the planted and the control tank demonstrated an 18-48 percent uptake by the cottonwood trees. Mass balance assessments showed 1,4-Dioxane uptake efficiency was positively correlated to cottonwood transpiration rates in the planted tank. The open pond 1,4-Dioxane measurements demonstrated a 64-85 percent reduction in 1,4-Dioxane concentration due to volatilization during the initial 120 hours pond lapse time. Elimination of 1,4-Dioxane from the ponds followed first order kinetics. Field and laboratory side experiments demonstrated the potential for UV photo degradation of 1-4-Dioxane.
3

A study of the ternary system : dioxane-tetrahydropyran-dinitrogen tetroxide /

Gibbins, Betty Jane January 1953 (has links)
No description available.
4

Bioaugmentation of TreeWells® to Enhance the Aerobic Degradation of 1,4-Dioxane at High Concentrations

Witt, Betsy Suzanne January 2018 (has links)
No description available.
5

A study of molecular addition compounds : A. Dinitrogen tetroxide with aliphatic and alicyclic ethers ; B. Dinitrogen pentoxide with dioxane and tetrahydropyran ; C. Iodine monochloride with phosphorus(III) chloride /

Guthrie, Frances Jean January 1953 (has links)
No description available.
6

Quantitative determination of emerging contaminants, solvent stabilizers and fullerene nanomaterials, in biological and environmental systems /

Isaacson, Carl W. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 122-129). Also available on the World Wide Web.
7

The rearrangement of [alpha]-phenylallyl alcohol in aqueous dioxane

Dilgren, Richard Evarts, January 1959 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 88-89).
8

The condensation of hydrazines and [beta]-diols with 2,5-hexanedione and 2,5-diethoxytetrahydrofuran

Sheeley, Richard M. 01 June 1964 (has links)
The objective of this series of investigations was two-fold: (1) to investigate new synthetic routes to the sterically hindered amines and hydrazines, and (2) the preparation of potential hypotensive and anticholinergic agents to be screened for pharmacological activity. A series of N-(substituted amino)-2,5-dimethylpyrroles was synthesized by means of the Knorr-Paal condensation, and the N-alkylamino analogs were found to undergo catalytic hydrogenation to the corresponding pyrrolidines, while the N-arylamino compounds underwent no reaction or yielded to N-N bond cleavage, depending upon severity of the conditions. In applications expanding upon the fundamental ground-work laid by Broadbent and Olsen^1 a series of 4-substituted 1,7-dimethyl-2,6-dioxa-10-azatricyclo[5.2.1.0^4,10]decanes was prepared by the interchange reaction of sterically hindered carboxylic and carbamic acid esters with 1,7-dimethyl- 4-hydroxymethyl-2,6-dioxa-10-azatricyclo[5.2.1.04,10]decane. Other exploratory work in this area resulted in the preparation of the 4-ethoxymethyl analog of the tricyclic nucleus by the Williamson synthesis. A correlation was made between the synthesis of the 1,7-dimethyl-2,6-dioxa-10-azatricyclo[5.2.1.0^4,10]decanes by condensation of 2-amino-1,3-propanediols with 2,5-hexanedione and the more common Knorr-Paal reaction of primary amines with the same diketone. These results indicated that both pathways were functioning simultaneously in the condensation of 2-amino-1,3-propanediols with Υ-diketones or their equivalent, production of the tricyclic system taking preference over pyrrole formation when the effects of steric hindrance become operative. As an outgrowth of studies directed toward the synthesis of analogous heterotricyclic systems a family of 2,2'- ethylenebis(1,3-dioxanes) was prepared. The 5-amino-5- methyl compound of this series was found to form a stable N-bromo derivative and is undergoing further consideration in regard to this property. These investigations also led to the synthesis of the parent compound of the 2,2'-ethylenebis(1,3-dithiane) series. All compounds synthesized during the course of this research have been submitted to private industry for pharmacological screening as well as to the Cancer Chemotherapy National Service Center. Pharmacological data resulting from this work is not currently available for public use.
9

Studies of the physical and chemical properties of 1,4 dioxane and their relevance to adsorption and transdermal absorption

Mahdi, Ali Jafar January 1900 (has links)
Doctor of Philosophy / Department of Diagnostic Medicine/Pathobiology / Deon van der Merwe / 1,4-Dioxane is a potentially carcinogenic solvent. It is a problematic groundwater contaminant because of its unique physical-chemical properties. It is found in a wide range of consumer products as a by-product contaminant. This research aimed to investigate contaminant properties and behavior of dioxane in the environment and also in the human body. The dioxane ability to decontamination by adsorption processes was evaluated with four adsorbents. The adsorption efficiencies of activated carbon (AC), metal oxide nanomaterials (TiO[subscript]2 and MgO), and diatomaceous earth (DE) were assessed in aqueous and vapor phases using infrared spectroscopy. AC showed the highest adsorptive capacity for dioxane at equilibrium in both phases. The rate and extent of dermal absorption are important in the analysis of risk from dermal exposure to dioxane. For this purpose, a new flow through diffusion system (FTDS) was developed by modifying a Bronaugh flow through diffusion cell with flow capacity in both the donor and receptor compartments and using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) as the analytical technique. FTDS can provide ‘real time’ quantitative high-density permeation data over time and is characterized by the simplicity of its use and the low cost of test samples. The in vitro dermal absorption study of dioxane across human skin showed that the absorption parameters of dioxane were 1.16 ± 0.22 hr, 5.7 X 10[superscript]-4 ± (0.62) cm/hr, 0.286 ± 0.035 mg/cm2/hr, 4.8 X 10-5 (± 0.32) cm[superscript]2/hr, and 1.99 ± 0.086 mg for lag time, permeability, steady-state flux, diffusivity, and total amount absorbed over 8 hr, respectively. The study of the effect of the surfactant sodium lauryl sulphate and solvent systems water, ethanol, propylene glycol, and ethyl acetate on permeation profiles revealed that these solvents and surfactants increased the permeation of dioxane significantly. The FT-IR spectra of stratum corneum treated with solvents showed that there was broadening of the CH[subscript]2 asymmetric stretching vibration of the CH[subscript]2 peak near 2920 cm[superscript]-1 only in samples treated with ethanol. The lipid extract precipitates were detected and were mostly composed of the stratum corneum lipid part.
10

Fluorinated tolane and dioxane liquid crystals for ferroelectric display applications

Dong, Chu Chuan January 1994 (has links)
No description available.

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