66 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Polymers"  
Results: 1 - 24 next
open access

Hypotheses for Scratch Behavior of Polymer Systems that Recover

Description: Scratch recovery is a desirable property of many polymer systems. The reason why some materials have demonstrated excellent scratch recovery while others do not has been a mystery. Explaining the scratch resistance based upon the hardness of a material or its crosslink density is incorrect. In this thesis, novel polymers were tested in an attempt to discover materials that show excellent scratch recovery - one of the most important parameters in determining the wear of a material. Several hypo… more
Date: May 2002
Creator: Bujard, Bernard
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Correlations of Polyimides and Blended Polyimides for High Temperature Gas Separations

Description: High performance polymers are of interest for high temperature gas separations, especially for the sequestration of carbon dioxide. A new family of high performance imide polymers has been identified as a successful membrane capture material. VTEC polyimides possess desired thermal properties (up to 500 °C) along with being robust and flexible even after multiple thermal cycles (up to 400 °C). Polyimides (PI) are excellent materials for high selectivity for smaller kinetic diameter gases such a… more
Date: March 1, 2002
Creator: Klaehn, John R.; Orme, Christopher J.; Luther, Thomas A.; Peterson, Eric S. & Urban-Klaehn, Jagoda M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Novel (meth)acrylate monomers for ultrarapid polymerization and enhanced polymer properties

Description: Ultraviolet light is known to be one of the most efficient methods to initiatc polymeric reactions in the presence of a photonitiator. Photopolymerizations are advantageous because the chemistry of the materials can be tailored to design liquid monomers for ultrarapid polymerization into a solid polymer material. One way to achieve rapid photopolymerizations is to utilize multifunctional (meth)acrylate monomers. which form highly crosslinked polymers; however, these monomers typically do not ac… more
Date: January 1, 2002
Creator: Beckel, E. R. (Eric R.); Berchtold, K. A. (Kathryn A.); Nie, J. (Jun); Lu, H. (Hui); Stansbury, J. W. (Jeffrey W.) & Bowman, C. N. (Christopher N.)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Nanodroplet quantification: pushing the detection limits of micro x-ray fluorescence

Description: In this study, detection limits for a variety of elements were determined on an EDAX Eagle I1 MXRF system equipped with a polycapillary and a Rh X-ray source. Both mass, volume, and spot diameter detection limits were established using dried spot technology, where various volumes and/or masses of different elements were deposited on different substrates, dried, and quantitatively analyzed by MXRF. Preliminary results have shown that sub-nanogram levels of material can be detected in less than 2… more
Date: January 1, 2002
Creator: Miller, T. C. (Thomasin C.) & Havrilla, G. J. (George J.)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Materials characterization using micro-x-ray fluorescence elemental imaging.

Description: Materials characterization continues to be a key challenge in a variety of programs. Although bulk elemental composition provides overall concentration of both major and trace elements, the distribution of these elements both on micro and macro scales can determine the performance and ultimately the physical properties of the materials. Hence elemental imaging can provide a new level of information for major and in some cases bulk trace concentrations of elements. Micro X-ray fluorescence (MXRF… more
Date: January 1, 2002
Creator: Havrilla, G. J. (George J.); Miller, T. C. (Thomasin C.) & Joseph, M. R. (Martha R.)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Radiation chemistry of polymeric components of radioactive waste

Description: The presentation covers fragments of research on the role of radiation chemistry in radioactive waste management. Radioactive waste often contains polymeric materials contaminated with actinides, which exhibit a activity for thousands of years. Rules of safety of transportation and environmental security of permanent storage demand the understanding of radiation chemistry of typical waste matrices. Due to a slow decay and a short range of penetration of a emitters, the experiments with actinide… more
Date: January 1, 2002
Creator: Dziewinski, J. J. (Jacek J.) & Zagorski, Z. (Zbigniew)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Thermal Degradation studies of nitroplasticized estane 5703 utilizing [sup 13] C enriched model polymers.

Description: Predicting the lifetime of PBX 9501 is critical to assurance of the reliability of the nuclear weapons stockpile. Ln support of the Lifetime Prediction Model, we have been investigating the physical and chemical aging processes that can potentially affect the lifetime of PBX 9501. Surveillance data of stockpile PBX 9501 binder have shown a decrease in Estane molecular weight as a fiinction of age. Estane is a poly(ester urethane) consisting of poly(buly1ene adipate) as the flexible soft segment… more
Date: January 1, 2002
Creator: Wrobleski, Debra A.; Langlois, D. A. (David A.); Orler, E. B. (E. Bruce); Schoonover, J. R. (Jon R.); Osborn, J. C. (Jill C.) & Small, J. H. (James H.)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Transient PrOx carbon monoxide measurement, control, and optimization

Description: Fuel processing systems for low temperature polymer electrolyte membrane (PEM) fuel cell systems require control of the carbon monoxide concentration to less than 100 ppm to 10 ppm in the anode feed. Conventional hydrocarbon fuel processors use a water-gas shift (WGS) reactor to react CO with water to form H2 and reduce the CO concentration. The CO conversion is limited by equilibrium at the outlet temperature of the WGS reactor. The WGS outlet CO concentration can range from over 1% to 2000 pp… more
Date: January 1, 2002
Creator: Inbody, M. A. (Michael A.); Borup, R. L. (Rodney L.) & Tafoya, J. (Jose I.)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Radiative shocking and acceleration of polycrystalline slabs for investigation of ablative Rayleigh-Taylor instability triggered by ablator microstructure

Description: It is vital to identify and control all perturbation sources that could trigger ablative Rayleigh-Taylor instability One obvious perturbation 'seed' is surface roughness computed perturbation growth, validated by experiments - Specification for allowable roughness of NIF ignition capsule' is based on But what about infernal microstructure of shell materials? - Beryllium shells are composed of individual crystalline grains with - Polymer shells are composed of long molecular chains that might 's… more
Date: January 1, 2002
Creator: Hoffman, N. M. (Nelson M.); Tubbs, D. L. (David L.); Swift, D. C. (Damian C.); Cobble, J. A. (James A.); Kyrala, George A. & Tierney, T. (Thomas)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Development of Low Cost Carbonaceous Materials for Anodes in Lithium-Ion Batteries for Electric and Hybrid Electric Vehicles

Description: Final report on the US DOE CARAT program describes innovative R & D conducted by Superior Graphite Co., Chicago, IL, USA in cooperation with researchers from the Illinois Institute of Technology, and defines the proper type of carbon and a cost effective method for its production, as well as establishes a US based manufacturer for the application of anodes of the Lithium-Ion, Lithium polymer batteries of the Hybrid Electric and Pure Electric Vehicles. The three materials each representing a sep… more
Date: December 10, 2002
Creator: Barsukov, Igor V.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Effect of BPSH post treatment on DMFC performance and properties

Description: Direct methanol fuel cells (DMFCs) are being investigated for applications ranging from milliwatt (cell phones) to kilowatt (MUS) size scales. A common pitfall for DMFCs has been the inability of the electrolyte, typically Nafion, to act as an effective methanol barrier. Methanol crossover adversely affects the cell by lowering the cell voltage due to a mixed potential at the cathode and lower fuel utilization. Improved DMFC performance was demonstrated with sulfonated poly(arylene ether sulfon… more
Date: January 1, 2002
Creator: Kickner, Michael; Yuseung, Kim; McGrath, James E.; Zelenay, Piotr & Pivovar, Bryan Scott
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A Hybrid Gas Cleaning Process for Production of Ultraclean Syngas

Description: The overall objective of this project is to develop technologies for cleaning/conditioning IGCC generated syngas to meet contaminant tolerance limits for fuel cell and chemical production applications. The specific goals are to develop processes for (1) removal of reduced sulfur species to sub-ppm levels using a hybrid process consisting of a polymer membrane and a regenerable ZnO-coated monolith or a mixed metal oxide sorbent; (2) removal of hydrogen chloride vapors to sub-ppm levels using an … more
Date: September 20, 2002
Creator: Merkel, Timothy C.; Turk, Brian S.; Gupta, Raghubir P.; Cicero, Daniel C. & Jain, Suresh C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Optical and Microcantilever-Based Sensors for Real-Time In Situ Characterization of High-Level Waste

Description: Fundamental research is being conducted to develop sensors for strontium that can be used in real-time to characterize high-level waste (HLW) process streams. Two fundamentally different approaches are being pursued, which have in common the dependence on highly selective molecular recognition agents. In one approach, an array of chemically selective sensors with sensitive fluorescent probes to signal the presence of the constituent of interest are coupled to fiber optics for remote analytical … more
Date: June 1, 2002
Creator: Braun, Gilbert M. & Bryan, Samuel
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

DEMONSTRATION SOLIDIFICATION TESTS CONDUCTED ON RADIOACTIVELY CONTAMINATED ORGANIC LIQUIDS AT THE AECL WHITESHELL LABORATORIES

Description: The AECL, Whiteshell Laboratory (WL) near Pinawa Manitoba, Canada, was established in the early 1960's to carry out AECL research and development activities for higher temperature versions of the CANDU{reg_sign} reactor. The initial focus of the research program was the Whiteshell Reactor-1 (WR-1) Organic Cooled Reactor (OCR) that began operation in 1965. The OCR program was discontinued in the early 1970's in favor of the successful heavy-water-cooled CANDU system. WR-1 continued to operate un… more
Date: February 25, 2002
Creator: Ryz, R. A.; Brunkow, W. G.; Govers, R.; Campbell, D. & Krause, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The Nochar® Technology Deployment Program, Providing a Proven Method Worldwide for Waste Solidification and Stabilization

Description: With the recent fall of the Soviet government and the decommissioning of defense plants in the U.S. DOE Complex, and the increasing worldwide emphasis on environmental restoration and controls, a critical need has developed for a proven ''off the shelf'' technology to deal with these enormous hazardous waste issues. While many new technologies are on the horizon and under development to handle complex waste streams, few of these offer immediate solutions. High technology polymers are an answer … more
Date: February 25, 2002
Creator: Brunkow, W. G.; Govers, R.; Pietsch, C.; Kelley, D. & Krause, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Electroactive Materials for Anion Separation -- Technetium from Nitrate

Description: The general aim of this project is to design and prepare new electroactive ion-exchange (EaIX) materials that can be used to remove the radioactive components from high-level radioactive waste (HLW) at U.S. Department of Energy (DOE) sites nationwide. The specific objective is to develop and investigate redox-active polymers, such as polyvinylferrocene (PVF), that can be used to remove pertechnetate (TcO{sub 4{sup -}}) ion from HLW. Electroactive materials are an important class of materials fo… more
Date: June 1, 2002
Creator: Hubler, Timothy L.; McBreen, James; Smyrl, William H.; Rassat, Scot D. & Lilga, Michael A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Recovery of entrained CSSX solvent from caustic aqueous raffinate using coalescers.

Description: A solvent was developed at Oak Ridge National laboratory (ORNL) for a caustic-side solvent extraction (CSSX) process that removes cesium from Savannah River Site (SRS) tank waste. After treatment, a small fraction of the solvent is entrained in the caustic raffinate at a level of 100-300 ppm, well above the solubilities for the various solvent components. Recovery of this solvent can produce a potential cost saving in excess of $5M per annum based on a processing rate of 20 gpm. In this study w… more
Date: December 13, 2002
Creator: Pereira, C.; Arafat, H. A.; Falkenberg, J. R.; Regalbuto, M. C. & Vandegrift, G. F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Adaptive Full-Spectrum Solar Energy Systems Cross-Cutting R&D on Adaptive Full-Spectrum Solar Energy Systems for More Efficient and Affordable Use of Solar Energy in Buildings and Hybrid Photobioreactors

Description: This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports day light from a paraboloidal dish concentrator to a luminaire via a large core polymer fiber optic. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of day lighting and fluorescent lighting for office lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrat… more
Date: September 1, 2002
Creator: Wood, Byard D. & Muhs, Jeff D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

FRACTIONATION OF LIGNOCELLULOSIC BIOMASS FOR FUEL-GRADE ETHANOL PRODUCTION

Description: PureVision Technology, Inc. (PureVision) of Fort Lupton, Colorado is developing a process for the conversion of lignocellulosic biomass into fuel-grade ethanol and specialty chemicals in order to enhance national energy security, rural economies, and environmental quality. Lignocellulosic-containing plants are those types of biomass that include wood, agricultural residues, and paper wastes. Lignocellulose is composed of the biopolymers cellulose, hemicellulose, and lignin. Cellulose, a polymer… more
Date: October 1, 2002
Creator: Guffey, F.D. & Wingerson, R.C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Switchable Hydrophobic-Hydrophilic Surfaces

Description: Tethered films of poly n-isopropylacrylamide (PNIPAM) films have been developed as materials that can be used to switch the chemistry of a surface in response to thermal activation. In water, PNIPAM exhibits a thermally-activated phase transition that is accompanied by significant changes in polymer volume, water contact angle, and protein adsorption characteristics. New synthesis routes have been developed to prepare PNIPAM films via in-situ polymerization on self-assembled monolayers. Swellin… more
Date: December 1, 2002
Creator: BUNKER, BRUCE C.; HUBER, DALE L.; KENT, MICHAEL S.; YIM, HYUN; CURRO, JOHN G.; LOPEZ, GABRIEL P. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Pyrolysis and Combustion of Acetonitrile (CH{sub 3}CN)

Description: Acetonitrile (CH{sub 3}CN) is formed from the thermal decomposition of a variety of cyclic, noncyclic, and polymeric nitrogen-containing compounds such as pyrrole and polyacrylonitrile. The pyrolysis and combustion of acetonitrile have been studied over the past 30 years to gain a more detailed understanding of the complex mechanisms involved in the release of nitrogen-containing compounds such as hydrogen cyanide (HCN) in fires and nitrogen oxides (NOx) in coal combustion. This report reviews … more
Date: May 22, 2002
Creator: Britt, P. F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Probing the interaction of amphiphilic triblockcopolymers with a biomimetic membrane.

Description: In the last several years, there has been growing interest in the use of synthetic surfactants to augment cellular repair. Amphiphilic triblock copolymers such as PEO-PPO-PEO have been demonstrated to aid in the repair of a variety of cells. In spite of the reported success of these compounds in clinical trials, the mechanism of their interaction with cell membranes remains poorly understood. In this work, they describe their efforts to examine the effect of the mode of incorporation of tribloc… more
Date: February 4, 2002
Creator: Firestone, M. A. & Seifert, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Semiconductor nanorod liquid crystals

Description: Rodlike molecules form liquid crystalline phases with orientational order and positional disorder. The great majority of materials in which liquid crystalline phases have been observed are comprised of organic molecules or polymers, even though there has been continuing and growing interest in inorganic liquid crystals. Recent advances in the control of the sizes and shapes of inorganic nanocrystals allow for the formation of a broad class of new inorganic liquid crystals. Here we show the form… more
Date: January 28, 2002
Creator: Li, Liang-shi; Walda, Joost; Manna, Liberato & Alivisatos, A. Paul
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Scalable Computational Chemistry: New Developments and Applications

Description: The computational part of the thesis is the investigation of titanium chloride (II) as a potential catalyst for the bis-silylation reaction of ethylene with hexaclorodisilane at different levels of theory. Bis-silylation is an important reaction for producing bis(silyl) compounds and new C-Si bonds, which can serve as monomers for silicon containing polymers and silicon carbides. Ab initio calculations on the steps involved in a proposed mechanism are presented. This choice of reactants allows … more
Date: December 31, 2002
Creator: Alexeev, Yuri
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
Back to Top of Screen