114 Matching Results

Search Results

Advanced search parameters have been applied.

Thermal decomposition of UO{sub 3}-2H{sub 2}0

Description: The first part of the report summarizes the literature data regarding the uranium trioxide water system. In the second part, the experimental aspects are presented. An experimental program has been set up to determine the steps and species involved in decomposition of uranium oxide di-hydrate. Particular attention has been paid to determine both loss of free water (moisture in the fuel) and loss of chemically bound water (decomposition of hydrates). The influence of water pressure on decomposition has been taken into account.
Date: February 26, 1998
Creator: Flament, T.A.
Partner: UNT Libraries Government Documents Department

Determination of the Optimum Concentration of Sulfur Dioxide to be Used in Sweet Potato Dehydration

Description: The object of this paper is to determine the optimum concentration of sulfur dioxide to be used in the commercial dehydration of the sweet potato by this process. Attention has been given to two aspects of the problem, (1) the effect of sulfur dioxide upon the extraction of water from the sweet potato by mechanical means, and (2) the effect of sulfur dioxide upon the stability of the carotene in the sweet potato over a period of several months.
Date: 1941
Creator: Kearby, Howard Raymond
Partner: UNT Libraries

Subquality natural gas sweetening and dehydration potential of the physical solvent N-formyl-morpholine

Description: Almost all gas produced in the United States requires processing before it is placed in the transmission system. For approximately 50% of the gas, this is just dehydration. The remainder, however, requires processing that is more complex and costly. A report to the Gas Research Institute states that about 30% of the proven gas reserves contained sufficient nitrogen, carbon dioxide or hydrogen sulfide to be classified as a subquality.
Date: March 1, 1995
Creator: Semrau, J.T.; Palla, N. & Lee, A.L.
Partner: UNT Libraries Government Documents Department

DEHYDRATION CONDENSATION IN AQUEOUS SOLUTION

Description: EARLIER investigations have demonstrated that di-cyandiamide (DCDA), the dimer of cyanamide, can successfully promote the dehydration condensation of: (1) glucose and orthophosphate to give glucose-6-phosphate; (2) adenosine and orthophosphate to give adenosine-5'-monophosphate; (3) orthophosphate to give pyrophosphate; (4) alanine to give alanylalanine and alanylalanylalanine. These reactions were carried out in dilute aqueous solutions in the dark. (It was also demonstrated that the combination of ultra-violet light and dicyandiamide could promote the synthesis of dipeptides. This observation has since been confirmed by other investigators.) These experiments were designed to demonstrate one possible means by which such compounds could have been formed on the prebiotic Earth, thus providing materials needed for the origin of living systems. Dicyandiamide itself could have been, present on the primitive Earth as was demonstrated with the ultra-violet irradiation of cyanide solution.
Date: April 1, 1965
Creator: Steinman, Gary; Kenyon, Dean H. & Calvin, Melvin
Partner: UNT Libraries Government Documents Department

Spectrophotometric and Calorimetric Studies of U(VI) Complexation with Sulfate at 25-70oC

Description: Sulfate, one of the inorganic constituents in the groundwater of nuclear waste repository, could affect the migration of radioactive materials by forming complexes. Spectrophotometric and microcalorimetric titrations were performed to identify the U(VI)/sulfate complexes and determine the equilibrium constants and enthalpy of complexation at 25-70 C. Results show that U(VI) forms moderately strong complexes with sulfate, i.e., UO{sub 2}SO{sub 4}(aq) and UO{sub 2}(SO{sub 4}){sub 2}{sup 2-}, in this temperature range and the complexes become stronger as the temperature is increased: 2-fold and 10-fold increases in the stability constants of UO{sub 2}SO{sub 4}(aq) and UO{sub 2}(SO{sub 4}{sub 2}{sup 2-}), respectively, when the temperature is increased from 25 C to 70 C. The complexation is endothermic and entropy-driven, showing typical characteristics of inner-sphere complexation and 'hard acid'/'hard base' interactions. The thermodynamic trends are discussed in terms of dehydration of both the cation (UO{sub 2}{sup 2+}) and the anion (SO{sub 4}{sup 2-}) as well as the effect of temperature on the structure of water.
Date: October 30, 2008
Creator: Tian, Guoxin & Rao, Linfeng
Partner: UNT Libraries Government Documents Department

ISOBUTANOL FROM SYNGAS IN A THREE PHASE SYSTEM

Description: With growing interest in oxygenates as octane booster for automotive fuels, various synthesis routes for these chemicals are being investigated. Among others, alternative routes to isobutene, the C4-components in MTBE-synthesis are under investigation. A promising path to isobutene is the heterogeneously catalyzed CO-hydrogenation to isobutanol with following dehydration (Fig. 1). As shown by thermodynamical studies, the heterogeneously catalyzed CO-hydrogenation to isobutanol is not expected to experience any thermodynamic constraints. However, heterogeneous hydrogenation of CO is a very exothermic process, a problem which can only be partly solved when being conducted in a plug flow reactor. When carried out in reaction vessels with moving catalyst bed (e.g. three phase stirred tank), heat transfer problems can be resolved, along with additional benefits connected with this reactor type. Several heterogeneous catalytic systems have been under investigation for their capability of isobutanol synthesis from syngas. Most promising catalysts for an active and selective isobutanol synthesis from CO are modified high temperature methanol catalysts.
Date: December 29, 2002
Creator: Tijrn, Peter
Partner: UNT Libraries Government Documents Department

Shrinkage and microstructural development during drying of organically modified silica xerogels

Description: We have studied the different driving forces behind syneresis in MTES/TEOS gels by aging them in different H{sub 2}O/EtOH pore fluids. We show using shrinkage, density, contact angle, and N{sub 2} sorption measurements, the influence of gel/solvent interactions on the microstructural evolution during drying. Competing effects of syneresis (that occurs during aging) and drying shrinkage resulted in the overall linear shrinkage of the organically modified gels to be constant at {approximately}50%. Increasing the hydrophobicity of the gels caused the driving force for syneresis to change from primarily condensation reactions to a combination of condensation and solid/liquid interfacial energy. In addition the condensation driven shrinkage was observed to be irreversible, whereas the interfacial free energy driven shrinkage was observed to be partially reversible. Nitrogen sorption experiments show that xerogels with the same overall extent of shrinkage can have vastly different microstructures due to the effects of microphase separation.
Date: July 1, 1996
Creator: Raman, N.K.; Wallace, S. & Brinker, C.J.
Partner: UNT Libraries Government Documents Department

Detecting plant metabolic responses induced by ground shock using hyperspectral remote sensing and physiological contact measurements

Description: A series of field experiments were done to determine if ground shock could have induced physiological responses in plants and if the level of the response could be observed. The observation techniques were remote sensing techniques and direct contact physiological measurements developed by Carter for detecting pre-visual plant stress. The remote sensing technique was similar to that used by Pickles to detect what appeared to be ground shock induced plant stress above the 1993 Non Proliferation Experiment`s underground chemical explosion. The experiment was designed to provide direct plant physiological measurements and remote sensing ratio images and from the same plants at the same time. The simultaneous direct and remote sensing measurements were done to establish a ground truth dataset to compare to the results of the hyperspectral remote sensing measurements. In addition, the experiment was designed to include data on what was thought to be the most probable interfering effect, dehydration. The experimental design included investigating the relative magnitude of the shock induced stress effects compared to dehydration effects.
Date: December 3, 1996
Creator: Pickles, W.L. & Cater, G.A.
Partner: UNT Libraries Government Documents Department

Relationship of shale dewatering and smectite dehydration to undercompaction occurrence

Description: The cause(s) of abnormal fluid pressures in sedimentary basins are not clearly understood. One step in determining the mechanism(s) of abnormal pressure generation in sedimentary basins is to develop an understanding of the relationship among undercompacted shale, abnormal pressure, and temperature. Our research focused on understanding undercompaction and how it related to smectite-illite conversion. A series of carefully designed experiments were used to help clarify and evaluate the relationship of smectite-illite transformation to undercompaction.
Date: December 1, 1996
Creator: Leftwich, J.T. Jr.
Partner: UNT Libraries Government Documents Department

Dehydration of plutonium trichloride hydrate

Description: A process of preparing anhydrous actinide metal trichlorides of plutonium or neptunium by reacting an aqueous solution of an actinide metal trichloride selected from the group consisting of plutonium trichloride or neptunium trichloride with a reducing agent capable of converting the actinide metal from an oxidation state of +4 to +3 in a resultant solution, evaporating essentially all the solvent from the resultant solution to yield an actinide trichloride hydrate material, dehydrating the actinide trichloride hydrate material by heating the material in admixture with excess thionyl chloride, and recovering anhydrous actinide trichloride is provided.
Date: December 31, 1991
Creator: Foropoulos, J. Jr.; Avens, L.R. & Trujillo, E.A.
Partner: UNT Libraries Government Documents Department

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

Description: Efforts this quarter have concentrated on design and planning for of a 50 MM scf/d dehydration skid testing at ChevronTexaco's Headlee Gas Plant in Odessa, TX. Potting and module materials testing continued. Construction of the bench-scale equipment continued. Additional funding to support the test was obtained through a contract with Research Partnership for Secure Energy for America. GTI has decreased the effort under this contract pending DOE's obligation of the total contract funding.
Date: July 1, 2004
Creator: Meyer, Howard S.
Partner: UNT Libraries Government Documents Department

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

Description: Efforts this quarter have concentrated on design and planning for of a 50 MM scf/d dehydration skid testing at ChevronTexaco's Headlee Gas Plant in Odessa, TX. Potting and module materials testing concluded. Construction of the bench-scale equipment continued and a pre-engineering study on a subsea application of the technology was performed cofunded contracts with Research Partnership for Secure Energy for America and Gas Research Institute. GTI has decreased the effort under this contract pending DOE's obligation of the total contract funding.
Date: October 1, 2004
Creator: Meyer, Howard S.
Partner: UNT Libraries Government Documents Department

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

Description: Efforts this quarter have concentrated on field site selection. ChevronTexaco has signed a contract with Kvaerner process Systems for the 50 MM scf/d dehydration skid at their Headlee Gas Plant in Odessa, TX for a commercial-scale test. This will allow the test to go forth. A new test schedule was established with testing beyond the existing contract completion date. Potting and module materials testing continued. Construction of the bench-scale equipment was started. Additional funding to support the test was obtained through a contract with Research Partnership for Secure Energy for America.
Date: April 1, 2004
Creator: Meyer, Howard S.
Partner: UNT Libraries Government Documents Department

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

Description: Efforts this quarter have concentrated on design of and planning for a 50 MM scf/d dehydration skid testing at ChevronTexaco's Headlee Gas Plant in Odessa, TX. Potting and module materials testing concluded. Construction of the bench-scale equipment continued. GTI has decreased the effort under this contract pending DOE's obligation of the total contract funding.
Date: January 1, 2005
Creator: Meyer, Howard S.
Partner: UNT Libraries Government Documents Department

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

Description: Efforts this quarter have concentrated on field site selection. ChevronTexaco has signed a contract with Kvaerner process Systems for the 50 MM scf/d dehydration skid at their Headlee Gas Plant in Odessa, TX for a commercial-scale test. This will allow the test to go forth. A new test schedule was established with testing beyond the existing contract completion date. Potting and module materials testing continued. Construction of the bench-scale equipment was started. Additional funding to support the test was obtained through a contract with Research Partnership for Secure Energy for America.
Date: January 1, 2004
Creator: Meyer, Howard S.
Partner: UNT Libraries Government Documents Department

Gibbsite to Boehmite Transformation in Strongly Caustic and Nitrate Environments

Description: The transformation of gibbsite to boehmite in strongly caustic solutions was studied using quantitative X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy techniques. Under hydrothermal conditions we identified two transformation mechanisms; dehydration and in-situ nucleation and dissolution and nucleation. If the reaction container was not completely sealed, dehydration of gibbsite followed by in-situ nucleation of boehmite was the preferred mechanism. Boehmite produced fibrous boehmite particles within the amorphous matrix of the decomposed gibbsite particles, which exhibited a poorly crystalline structure and smaller size than the initial gibbsite particles. In a closed environment, the preferred mechanism was the dissolution of gibbsite along (001) planes. The final boehmite particles were not morphologically related to the initial gibbsite particles and could be many times larger than the gibbsite particles.
Date: November 26, 2002
Creator: Hobbs, D.T.
Partner: UNT Libraries Government Documents Department

The Effect of Rapid Weight Loss on the Efficiency of Wrestlers Under Simulated Competitive Conditions

Description: The purpose of this study was to determine the effects of rapid weight loss on wrestlers' efficiency incorporating competitive aspects of the sport into the research procedures. Six subjects were selected from the North Texas State University Wrestling Club. Eight cardiovascular and neuromuscular measurements were taken and recorded before treatment and following treatment. Astrand's bicycle ergometer test was utilized to obtain exhaustive, heart rates. Data were analyzed by a one-tailed t test at the .05 level. Conclusion of the investigation was that following 6.25 per cent rapid loss of body weight, over a period of one week, no loss of efficiency occurred among wrestlers under simulated competitive conditions.
Date: December 1977
Creator: Fabrizio, Anthony N.
Partner: UNT Libraries

MOLECULAR SIEVES AS CATALYSTS FOR METHANOL DEHYDRATION IN THE LPDMEtm PROCESS

Description: Several classes of molecular sieves were investigated as methanol dehydration catalysts for the LPDME{trademark} (liquid-phase dimethyl ether) process. Molecular sieves offer a number of attractive features as potential catalysts for the conversion of methanol to DME. These include (1) a wide range of acid strengths, (2) diverse architectures and channel connectivities that provide latitude for steric control, (3) high active site density, (4) well-investigated syntheses and characterization, and (5) commercial availability in some cases. We directed our work in two areas: (1) a general exploration of the catalytic behavior of various classes of molecular sieves in the LPDME{trademark} system and (2) a focused effort to prepare and test zeolites with predominantly Lewis acidity. In our general exploration, we looked at such diverse materials as chabazites, mordenites, pentasils, SAPOs, and ALPOs. Our work with Lewis acidity sought to exploit the structural advantages of zeolites without the interfering effects of deleterious Broensted sites. We used zeolite Ultrastable Y (USY) as our base material because it possesses a high proportion of Lewis acid sites. This work was extended by modifying the USY through ion exchange to try to neutralize residual Broensted acidity.
Date: April 1, 2002
Creator: Wang, Andrew W.
Partner: UNT Libraries Government Documents Department

A low-energy continuous reactor-separator for ethanol from starch, whey permeate, permeate mother liquor, molasses or cellulosics. Project final report, April 1, 1994--February 28, 1997

Description: In this project, a novel bio-reactor technology in which reaction is coupled with product separation was developed to pilot/demonstration scale. Combining reaction with separation during a fermentation allows the fermentation of highly concentrated feeds and allows the fermentation of streams with high levels of salts/non-fermentable inhibitors. Simultaneous saccharification and fermentation of polysaccharides such as starch and cellulose can also be combined with ethanol separation in the Continuous Stirred Reactor Separator (CSRS). Application of the bio-reactor to various substrates was investigated on a lab scale with fermentation of raw starch, cane molasses, xylose, whey permeate and permeate mother liquor. Flocculating yeast strains for high density sucrose/glucose fermentation were selected and adapted to form fast settling pellets. A strain of K marxianus capable of fermenting high salt permeate mother liquor was also selected and adapted. A low energy solvent ethanol recovery system was developed for ethanol recovery from the vapors leaving the reactor/separator. This Solvent Absorption/Extractive Distillation (SAED) process gives a low energy method for purifying the ethanol to an anhydrous product. The amount of energy needed to recover an anhydrous ethanol product from a CSRS stage running at 8% ethanol was calculated to be under 8,000 BTU/gallon. This process may also have further application in VOC (volatile organic carbon compounds) removal from air streams. During this project, a 24,000 Liter CSRS was designed, fabricated, installed, and operated at a small batch ethanol plant (Permeate Refining Inc) in NE Iowa. The reactor was operated on a semi-continuous basis over a period of 18 months. A Solvent Absorption Extractive Distillation (SAED) system was also recently completed and installed at the Permeate Refining Inc. site for ethanol recovery/dehydration.
Date: April 14, 1997
Creator: Dale, M.C. & Moelhman, M.
Partner: UNT Libraries Government Documents Department

Development of a catalyst for conversion of syngas-derived materials to isobutylene

Description: The initial objective of this program was to develop a catalyst and process for the conversion of synthesis gas to isobutylene via the isosynthesis process. Preliminary work directed at identifying potential catalysts for this reaction did not have promising results. Therefore, the objectives of this program were revised to the development of a catalyst and process for the conversion of synthesis gas to isobutanol. Two approaches have been investigated in this area: the direct conversion of synthesis gas to higher alcohols and indirect conversion via methanol produced using conventional methanol synthesis technology. The isosynthesis reaction for the conversion of synthesis gas to branched hydrocarbons was pioneered by German workers during World War II The primary products of this reaction are either isobutane or isobutylene depending on the catalyst system used. Thoria-based catalysts were found to give the highest yields, but virtually all of the products were alkanes. More recently, there have been several reports of olefin production using ZrO{sub 2}-based. The preliminary work in this program focussed on the evaluation of ZrO{sub 2} and modified ZrO{sub 2} catalysts for the direct conversion of CO/H{sub 2} to isobutylene via the isosynthesis reaction. All of the catalysts and conditions evaluated in this work gave isobutylene yields of less than 4% which is far below that required for an economically viable process. A summary of the key results from this portion of the project is given in Section 3.6. In view of the poor performance of these catalysts and the lack any encouraging results from other research groups working in the isosynthesis area, this approach was abandoned in favor of approaches related to higher alcohols synthesis.
Date: October 1, 1996
Creator: Barger, P.T.; Spehlmann, B.C. & Gajda, G.J.
Partner: UNT Libraries Government Documents Department

Task 23 - background report on subsurface environmental issues relating to natural gas sweetening and dehydration operations. Topical report, February 1, 1994--February 28, 1996

Description: This report describes information pertaining to environmental issues, toxicity, environmental transport, and fate of alkanolamines and glycols associated with natural gas sweetening and dehydration operations. Waste management associated with the operations is also discussed.
Date: December 31, 1998
Creator: Sorensen, J.A.
Partner: UNT Libraries Government Documents Department

Experimental investigation of kinetics and rheology during diagenesis

Description: Two processes of enormous economic consequence occur within the upper to middle crust: the formation, migration, entrapment, and degradation of hydrocarbons, and hazardous seismicity. Substantial scientific evidence suggests that both these processes are influenced by devolatilization reactions during diagenesis. However, surprisingly few laboratory studies have been conducted on materials actively undergoing low-grade metamorphism or diagenesis. Because of this, there exists no suitable basis for understanding the rates at which devolatilization occurs, and what effects this process has on deformation at shallow to moderate depths in the crust. The authors are conducting a coordinated deformation and kinetic study of an important devolatilization reaction: the breakdown of laumontite. Laumontite is a common zeolite whose equilibrium phase relations and room-temperature frictional behavior are well understood. Besides serving as a model system for more complicated rocks, laumontite is an important mineral in its own right, particularly for hydrocarbon fields in sandstones and for fault zones in the crust. Hydrostatic experiments are being conducted to investigate the kinetics and mechanism of laumontite dehydration, and triaxial deformation experiments will enable characterization of the effect of differential stress on the reaction and the effect of synkinematic dehydration on the mechanical behavior of rock. The authors anticipate results of significant import for hydrocarbon exploration and recovery and for understanding the strength and seismic potential of crustal fault zones.
Date: September 1, 1998
Creator: Liou, J.G. & Hacker, B.R.
Partner: UNT Libraries Government Documents Department

SYNCHROTRON X-RAY STUDY OF HYDRATION DYNAMICS IN THE SYNTHETIC SWELLING CLAY NA-FLUOROHECTORITE.

Description: We present time-resolved synchrotron x-ray diffraction from the swelling clay Na fluorohectorite during controlled hydration and dehydration. A comparison of bulk and surface scattering reveals that the time dependence of basal Bragg peak positions and intensities has two components, which come into play at distinct temperatures. Intercalation of water into the crystal structure commences at a temperature of about 60 C on a time scale on the order of 1 hour. By contrast, percolation of water into the porous medium has a characteristic time constant of 3-4 h. This is the rate limiting process for hydration of the interior of the clay for T > 40 C. We suggest that the temperature-dependent percolation step may account for some of the hysteresis reported in earlier diffraction studies of the hydration of similar systems.
Date: July 22, 2001
Creator: DIMASI, E.; FOSSUM, J.O. & DASILVA, G.J.
Partner: UNT Libraries Government Documents Department

NOVEL COMPOSITE MEMBRANES AND PROCESS FOR NATURAL GAS UPGRADING

Description: The first phase of this project involved the development of a high performance composite membranes for the treatment of natural gas. The objective of the second phase is to demonstrate the commercial potential of a full-size membrane module in a pilot scale field test. This phase is undertaken jointly with our commercial partner, UOP LLC. At the conclusion of Phase I, two composite membrane products had been developed for the enrichment (sweetening) of natural gas. The one was a low pressure membrane with a high CO{sub 2}/CH{sub 4} separation factor that falls within the target range of 25-30 (at 50 C) set for the program. This is a significant improvement over current commercial membranes that have separation factors of around 18-19. The second membrane had excellent high pressure capability and good contamination resistance, with a separation factor of 20-22. Based on the performance and the economic evaluation of the newly developed membranes, and with the input of UOP and DOE, it was decided to devote the demonstration phase of the program to the field testing and commercial evaluation of natural gas dehydration membranes. Due to the events of September 11, the program was also extended by 6 months until June 30, 2002. In Phase II, UOP has essentially completed preparation of the field test site. Site preparation included the re-design of the test system, purchase and installation of analytical equipment, and making the necessary piping and other hardware changes. IMS has produced two commercial sized dehydration membrane modules for the field tests. These have been successfully tested up to pressures expected in the field tests, and the modules have been shipped to the test site. The remainder of the program will comprise performance testing of the membrane modules, evaluation of the results and submission of the final report with recommendations.
Date: February 1, 2002
Creator: LeRoux, Johann
Partner: UNT Libraries Government Documents Department