33 Matching Results

Search Results

Advanced search parameters have been applied.

The Black Paintings (Dawn)

Description: Multiple wall size paintings of gray, peach and black striated vertical lines rendered on top of night or city landscape.
Access: This item is restricted to UNT Community Members. Login required if off-campus.
Date: 1986
Creator: Patkin, Izhar
Partner: UNT College of Visual Arts + Design

Endurance tests of a 22-inch-diameter pulse-jet engine with a neoprene-coated valve grid

Description: Report discussing the results of testing to determine the operating life of a 22-inch-diameter pulse-jet engine equipped with a neoprene-coated valve grid. The valve grid was found to extend the operating life and only reduced the performance slightly.
Date: October 3, 1945
Creator: Manganiello, Eugene J.; Valerino, Michael F. & Breisch, John H.
Partner: UNT Libraries Government Documents Department

Sensitivity tests on leaded glove material, EMRTC Report FR-95-15: Final test report

Description: Small-scale safety and characterization tests were performed on stored radioactive wastes. The materials tested were formed when leaded dry box gloves were exposed to nitric acid. The nitration products exhibited thermal and impact sensitivity which could lead to ignition of explosion. Water was used to separate the nitrated glove material into several fractions; only the insoluble fraction exhibited significant sensitivity to impact. Both the separated and mixed materials were thermally unstable. Self-heating occurred at about 80C or lower, depending on the quantity of material tested. The drop weight impact sensitivity of one sample was greater than that of trinitrotoluene. The electrostatic spark discharge sensitivity of the nitration products was measured to be less than for typical secondary explosives. No sensitivity to friction was measured. These results indicate that the nitrated gloves can probably be handled without extreme risk of ignition. Washing the nitrated materials was found to desensitize the materials, indicating that water could be used as a solvent when storing the materials.
Date: June 1, 1995
Creator: Olson, D.; Davis, L. & Block-Bolten, A.
Partner: UNT Libraries Government Documents Department

Prompt non-tire rubber recycling : final report for phases 1 and 2.

Description: This report summarizes an assessment conducted by Environmental Technologies Alternatives, Inc., under a subcontract to Argonne National Laboratory. The project was conducted in two phases. An assessment of alternative technologies for recycling of prompt non-tire rubber was conducted in the first phase, and an experimental program focusing on a new technology called the catalytic Regeneration Process offered the greatest opportunity for recovery of high-value recyclable rubber material. An experimental and large-scale test program was undertaken to further delineate the economic potential as an essential step leading to commercial deployment and to determine the course of continued development of the technology by the private sector. The experimental program defined process-operating conditions for the technology and verified the degree of devulcanisation achievable for two rubber compounds: ethylene-propylene-nonconjugated-diene monomer (EPDM) and neoprene. To determine product acceptance, samples of devulcanized EPDM and neoprene were prepared and used in factory trials for the production of automotive moldings (EPDM) and fiber-filled belting (neoprene). The factory trials indicated that the physical properties of the products were acceptable in both cases. The appearance of molded and calendared surface finishes was acceptable, while that of extruded finishes was unsatisfactory. The fiber-filled neoprene belting application offers the greatest economic potential. Process costs were estimated at $0.34/lb for neoprene waste rubber relative to a value of $0.57/lb. The results of the experimental program led to the decision to continue development of this technology is being planned, subject to the availability of about $3 million in financing from private-sector investors. The ability to recycle non-tire rubber scrap could conserve as much as 90,000 Btu/lb, thus yielding an estimated energy savings potential of about 0.25 quad/yr.
Date: June 25, 1999
Creator: Smith, F. G. & Daniels, E. J.
Partner: UNT Libraries Government Documents Department

Reducing System Artifacts in Hyperspectral Image Data Analysis with the Use of Estimates of the Error Covariance in the Data

Description: Hyperspectral Fourier transform infrared images have been obtained from a neoprene sample aged in air at elevated temperatures. The massive amount of spectra available from this heterogeneous sample provides the opportunity to perform quantitative analysis of the spectral data without the need for calibration standards. Multivariate curve resolution (MCR) methods with non-negativity constraints applied to the iterative alternating least squares analysis of the spectral data has been shown to achieve the goal of quantitative image analysis without the use of standards. However, the pure-component spectra and the relative concentration maps were heavily contaminated by the presence of system artifacts in the spectral data. We have demonstrated that the detrimental effects of these artifacts can be minimized by adding an estimate of the error covariance structure of the spectral image data to the MCR algorithm. The estimate is added by augmenting the concentration and pure-component spectra matrices with scores and eigenvectors obtained from the mean-centered repeat image differences of the sample. The implementation of augmentation is accomplished by employing efficient equality constraints on the MCR analysis. Augmentation with the scores from the repeat images is found to primarily improve the pure-component spectral estimates while augmentation with the corresponding eigenvectors primarily improves the concentration maps. Augmentation with both scores and eigenvectors yielded the best result by generating less noisy pure-component spectral estimates and relative concentration maps that were largely free from a striping artifact that is present due to system errors in the FT-IR images. The MCR methods presented are general and can also be applied productively to non-image spectral data.
Date: January 1, 2002
Creator: HAALAND, DAVID M.; VAN BENTHEM, MARK H.; WEHLBURG, CHRISTINE M. & KOEHLER,IV, FREDERICK W.
Partner: UNT Libraries Government Documents Department

General solutions for the oxidation kinetics of polymers

Description: The simplest general kinetic schemes applicable to the oxidation of polymers are presented, discussed and analyzed in terms of the underlying kinetic assumptions. For the classic basic autoxidation scheme (BAS), which involves three bimolecular termination steps and is applicable mainly to unstabilized polymers, typical assumptions used singly or in groups include (1) long kinetic chain length, (2) a specific ratio of the termination rate constants and (3) insensitivity to the oxygen concentration (e.g., domination by a single termination step). Steady-state solutions for the rate of oxidation are given in terms of one, two, three, or four parameters, corresponding respectively to three, two, one, or zero kinetic assumptions. The recently derived four-parameter solution predicts conditions yielding unusual dependencies of the oxidation rate on oxygen concentration and on initiation rate, as well as conditions leading to some unusual diffusion-limited oxidation profile shapes. For stabilized polymers, unimolecular termination schemes are typically more appropriate than bimolecular. Kinetics incorporating unimolecular termination reactions are shown to result in very simple oxidation expressions which have been experimentally verified for both radiation-initiated oxidation of an EPDM and thermoxidative degradation of nitrile and chloroprene elastomers.
Date: August 1, 1996
Creator: Gillen, K.T.; Clough, R.L. & Wise, J.
Partner: UNT Libraries Government Documents Department

Compatibility of refrigerants and lubricants with motor materials under retrofit conditions. Final report, Volume 1

Description: Compatibility tests were conducted on motor materials to determine if exposure to the original refrigerant/mineral oil would affect compatibility of the motor materials after retrofit to the alternative refrigerant/lubricant. The motor materials were exposed at elevated temperature to the original refrigerant and mineral oil for 500 hours, followed by exposure to the alternative refrigerant and lubricant for 500 hours. Measurements were also taken after 168 and 336 hours. As a control, some samples were exposed to the original refrigerant/mineral oil for a total of 1000 hours. The original refrigerants and the Alternatives tested for retrofit were as follows: Most motor materials exposed to the alternative refrigerant and lubricant (after an initial exposure to the original refrigerant and mineral oil) were compatible with the alternative refrigerant and lubricant. The only concern was delamination and blistering of the sheet insulation containing Nomex, especially after removal of absorbed refrigerant. This was attributed to solution of the adhesive and not to the Nomex itself. Embrittlement of the polyethylene terephthalate (PET) found in Mylar and Melinex sheet and sleeving insulations was initially observed, but subsequent tests under dry conditions showed that embrittlement of the PET materials was caused by moisture present during the exposure. Compatibility tests of elastomers with R-245ca, retrofitted from R-11 and R-123, showed that the nitrile was compatible with both R-11 and R-245ca, but not with R-123. The neoprene was unsatisfactory because of shrinkage in the R-245ca.
Date: October 1, 1996
Creator: Doerr, R.G. & Waite, T.D.
Partner: UNT Libraries Government Documents Department

[Recycle of contaminated scrap metal]: Task 1.3.2, Bulk solids feed system. Topical report, October 1993-- January 1996

Description: A critical requirement in DOE`s efforts to recycle, reuse, and dispose of materials from its decontamination and decommissioning activities is the design of a robust system to process a wide variety of bulk solid feeds. The capability to process bulk solids will increase the range of materials and broaden the application of Catalytic Extraction Processing (CEP). The term bulk solids refers to materials that are more economically fed into the top of a molten metal bath than by submerged injection through a tuyere. Molten Metal Technology, Inc. (MMT) has characterized CEP`s ability to process bulk solid feed materials and has achieved significant growth in the size of bulk solid particles compatible with Catalytic Extraction Processing. Parametric experimental studies using various feed materials representative of the components of various DOE waste streams have validated design models which establish the reactor operating range as a function of feed material, mass flow rate, and particle size. MMT is investigating the use of a slurry system for bulk solid addition as it is the most efficient means for injecting soils, sludges, and similar physical forms into a catalytic processing unit. MMT is continuing to evaluate condensed phase product removal systems and alternative energy addition sources to enhance the operating efficiency of bulk solids CEP units. A condensed phase product removal system capable of on-demand product removal has been successfully demonstrated. MMT is also investigating the use of a plasma arc torch to provide supplemental heating during bulk solids processing. This comprehensive approach to bulk solids processing is expected to further improve overall process efficiency prior to the deployment of CEP for the recycle, reuse, and disposal of materials from DOE decontamination and decommissioning Activities.
Date: July 1, 1996
Partner: UNT Libraries Government Documents Department

Permeation of chemicals through glove-box glove materials

Description: The resistance of two commercial gloves to 20 chemicals commonly used in glove boxes was studied. The chemicals were inorganic acids/bases/salts, organic acids, alcohols, glycols, halogen compounds, sulfur compounds, and hydrocarbons. The ASTM cell was used to study permeation of volatile organic compounds through protective clothing materials using air, flame ionization detector/gas chromatography; a modified version of the cell was used with isopropanol for the nonvolatile organic compounds. Permeation of inorganic compounds through the elastomers was studied using the ASTM cell with water, conductivity meter. A Teflon cell was used with HF and ammonium hydrofluoride. Results: Hypalon protects against all chemicals except trichloroethylene (TCE) and CCl{sub 4}. Acetic acid and ethanol permeated through neoprene, which also did not protect against TCE and CCl{sub 4}. Sulfuric acid dissolved neoprene in 5 h. Kerosene permeated through neoprene in 5 h. Although neoprene showed good resistance to cutting oil, TCE in cutting oil broke through in 61 min. Neoprene showed good protection against all the other chemicals with no breakthrough before 6 h.
Date: June 30, 1994
Creator: Vahdat, N,; Johnson, J. S.; Neidhardt, A.; Cheng, J. & Weitzman, D.
Partner: UNT Libraries Government Documents Department

THE EFFECT OF RADIATION ON THE MECHANICAL PROPERTIES OF POLYMERS. A BIBLIOGRAPHY OF THE UNCLASSIFIED LITERATURE, 1955-SEPTEMBER 1962

Description: A bibliography of approximates 440 references is presented which is arranged into sections dealing with polyacrylates, polyamides, polybutadienes and copolymers, polycarbonates, cellulosics, epoxy resins, polyesters, polyethers, polyethylenes, natural rubber, neoprene, phenolics, polypropylene, rubbers, silicones, polystyrenes, urethanes, polyvinylidenes, polyvinyls, and miscellaneous systems. Reviews, data compilations, books, and references dealing with dynamic mechanical properties are also listed. (D.L.C.)
Date: July 1, 1963
Partner: UNT Libraries Government Documents Department

Correlation of Chemical and Mechanical Property Changes During Oxidative Degradation of Neoprene

Description: The thermal degradation of a commercial, stabilized, unfilled neoprene (chloroprene) rubber was investigated at temperatures up to 140 C. The degradation of this material is dominated by oxidation rather than dehydrochlorination. Important heterogeneous oxidation effects were observed at the various temperatures investigated using infrared micro-spectroscopy and modulus profiling. Intensive degradation-related spectral changes in the IR occurred in the conjugated carbonyl and hydroxyl regions. Quantitative analysis revealed some differences in the development of the IR oxidation profiles, particularly towards the sample surface. These chemical degradation profiles were compared with modulus profiles (mechanical properties). It is concluded that the profile development is fundamentally described by a diffusion-limited autoxidation mechanism. Oxygen consumption measurements showed that the oxidation rates display non-Arrhenius behavior (curvature) at low temperatures. The current results, when compared to those of a previously studied, clay-filled commercial neoprene formulation, indicate that the clay filler acts as an antioxidant, but only at low temperatures.
Date: July 1, 1999
Creator: Celina, M.; Wise, J.; Ottesen, D.K.; Gillen, K.T. & Clough, R.L.
Partner: UNT Libraries Government Documents Department

Inhalation developmental toxicology studies: Developmental toxicity of chloroprene vapors in New Zealand white rabbits. Final report

Description: Chloroprene, 2-chloro-1,3-butadiene, is a colorless liquid with a pungent ethereal odor that is primarily used as an intermediate in the manufacture of neoprene rubber, and has been used as such since about 1930. This study addressed the potential for chloroprene to cause developmental toxicity in New Zealand white rabbits following gestational exposure to 0, 10, 40, or 175 ppm chloroprene vapors, 6h/dy, 7dy/wk. Each treatment group consisted of 15 artificially inseminated females exposed on 6 through 28 days of gestation (dg). Body weights were obtained throughout the study period, and uterine and fetal body weights were obtained at sacrifice on 29 dg. Implants were enumerated and their status recorded and live fetuses were examined for gross, visceral, skeletal, and soft-tissue craniofacial defects. There were no overt signs of maternal toxicity and the change in maternal body weight over the course of the study was not affected. Exposure of pregnant rabbits to chloroprene vapors on 6-28 dg had no effect on the number of implantation, the mean percent of live pups per litter, or on the incidence of resorptions per litter. The incidence of fetal malformations was not increased by exposure to chloroprene. Results of this study indicate that gestational exposure of New Zealand white rabbits to 10, 40, or 175 ppm chloroprene did not result in observable toxicity to either the dam or the offspring.
Date: April 1, 1994
Creator: Mast, T. J.; Evanoff, J. J.; Westerberg, R. B.; Rommereim, R. L. & Weigel, R. J.
Partner: UNT Libraries Government Documents Department

Final report for Allied-Signal Aerospace Company, Kansas City Division on protective glove permeation analysis

Description: We conducted 25 separate glove fabric permeation studies during this project. The permeations were carried out in the small (1 inch) glass ASTM cell. One other permeation study was carded out with a large (two inch) modified ASTM cell for comparison with the small cell results. We also compared the LLNL procedure from both large and small cells with the standard ASTM test procedure which uses a liquid solution on the breakthrough side of the fabric (the liquid is then sampled on a periodic basis). In all comparisons we observed a close-correlation in breakthrough times between the two procedures and the two cell sizes. In the course of this study, we tested ten different glove materials. These included neoprene (original ASTM round-robin sheet stock, 16 mil thickness), Edmont Sol-Vex (nitrile), Pioneer nitrile, Pioneer Pylox (polyvinyl chloride), North Viton (trademark for fluoroelastomers), North SilverShield (Norfoil, trademark for a flexible metallized laminate), Safety 4 4H (patented plastic laminate), and QRP PolyTuff (polyurethane) 20G-2000 (5 mil), 23G-2300 (1.5 mil), and 25G-2500 (1.5 mil). Three of the glove materials, Viton and Silver Shield (North), and 4H (Safety 4), did not allow any permeation measurable by our system to either 1,2-dichloroethane or 3% diphenylmercury (in 1,2-dichloroethane) for a period greater than six hours. A fourth material, QRP Poly Tuff 2OG-2000, did not allow any measurable penetration of Asilamine (an aromatic diamine) for a time pedod of greater than 4 hours. Breakthrough times and curves were obtained for all other tested materials. Eleven different chemicals were used to challenge the glove materials. These included acetone, Asilamine, 1,2-dichloroethane, dichloromethane, isopropyl alcohol, a mixture of 3% diphenylmercury in 1,2-dichloroethane (w/w), phenol, and lso Verre Stripper, 4,4`-methylenedianil (MDA), 1,3-phenylenediamine (MPDA), and Shell Epon (R) curing agent Z.
Date: June 22, 1990
Creator: Swearengen, P. M.; Johnson, J. S. & Priante, S. J.
Partner: UNT Libraries Government Documents Department

Generation of volatile organic compounds by alpha particle degradation of WIPP plastic and rubber material

Description: The generation of volatile organic compounds (VOCs), hydrogen, and carbon oxides due to alpha particle irradiation of polyethylene, polyvinylchloride, hypalon, and neoprene, is being investigated. A wide diversity of VOCs was found including alkenes, alkanes, alcohols, ketones, benzene derivatives, and nitro compounds. Their yields however, were quite low. The relative amounts of these compounds depended on the material, atmosphere present, and the absorbed dose. This investigation will help evaluate the effect of ionizing radiation on the long-term performance assessment and regulatory compliance issues related to the Waste Isolation Pilot Plant (WIPP).
Date: December 31, 1993
Creator: Reed, D. T. & Molecke, M. A.
Partner: UNT Libraries Government Documents Department

Compatibility of selected elastomers with plutonium glovebox environment

Description: This illustrative test was undertaken as a result of on-going failure of elastomer components in plutonium gloveboxes. These failures represent one of the major sources of required maintenance to keep gloveboxes operational. In particular, it was observed that the introduction of high specific activity Pu-238 into a glovebox, otherwise contaminated with Pu-239, resulted in an inordinate failure of elastomer components. Desiring to keep replacement of elastomer components to a minimum, a decision to explore a few possible alternative elastomer candidates was undertaken and reported upon herewith. Sample specimens of Neoprene, Urethane, Viton, and Hypalon elastomeric formulations were obtained from the Bacter Rubber Company. Strips of the elastomer specimens were placed in a plutonium glovebox and outside of a glovebox, and were observed for a period of three years. Of the four types of elastomers, only Hypalon remained completely viable.
Date: June 1, 1994
Creator: Burns, R.
Partner: UNT Libraries Government Documents Department

Microbial Gas Generation Under Expected Waste Isolation Pilot Plant Repository Conditions: Final Report

Description: Gas generation from the microbial degradation of the organic constituents of transuranic (TRU) waste under conditions expected in the Waste Isolation Pilot Plant (WIPP) was investigated. The biodegradation of mixed cellulosic materials and electron-beam irradiated plastic and rubber materials (polyethylene, polyvinylchloride, hypalon, leaded hypalon, and neoprene) was examined. We evaluated the effects of environmental variables such as initial atmosphere (air or nitrogen), water content (humid ({approx}70% relative humidity, RH) and brine inundated), and nutrient amendments (nitogen phosphate, yeast extract, and excess nitrate) on microbial gas generation. Total gas production was determined by pressure measurement and carbon dioxide (CO{sub 2}) and methane (CH{sub 4}) were analyzed by gas chromatography; cellulose degradation products in solution were analyzed by high-performance liquid chromatography. Microbial populations in the samples were determined by direct microscopy and molecular analysis. The results of this work are summarized.
Date: July 1, 2011
Creator: Gillow, J. B. & Francis, A.
Partner: UNT Libraries Government Documents Department