Search Results

open access

Pyrolysis of surface-immobilized model compounds: Mechanistic implications for the thermal chemistry of coal

Description: Our research has been investigating the potential role that the cross-linked network structure of coal may play in perturbing free-radical reactions associated with coal thermolysis. This may be particularly important in the thermal conversion of coal at low temperatures, e.g., 350--400{degree}C, where bonds begin to break but most of the residual framework is retained. In order to assess the potential impact of restricted transport on thermal reaction pathways, we have modeled the phenomenon experimentally by studying organic model compounds that are covalently linked to an inert silica surface. The experimental methodology and significant results from studies of the thermolysis of surface-attached Ph(CH{sub 2}){sub n}Ph (n = 0--4) at 345--400{degree}C will be briefly surveyed. Initial results from studies of two-component surfaces will also be presented that reveal the role of radical migration, via facile hydrogen shuttling, in modifying the effects of diffusional constraints. 13 refs., 5 figs.
Date: January 1, 1990
Creator: ,; Britt, P F & Poutsma, M L
Partner: UNT Libraries Government Documents Department
open access

UPDATE: nuclear power program information and data, July-September 1981

Description: UPDATE is published by the Office of Coordination and Special Projects, Office of Nuclear Reactor Programs, to provide a quick reference source on the current status of nuclear powerplant construction and operation in the United States and for information on the fuel cycle, economics, and performance of nuclear generating units. Similar information on other means of electric generation as related to nuclear power is included when appropriate. The subject matter of the reports and analyses presented in UPDATE will vary from issue to issue, reflecting changes in foci of interest and new developments in the field of commercial nuclear power generation. UPDATA is intended to provide a timely source of current statistics, results of analyses, and programmatic information proceeding from the activities of the Office of Nuclear Reactor Programs and other components of the Department of Energy, as well as condensations of topical articles from other sources of interest to the nuclear community. It also facilitates quick responses to requests for data and information of the type often solicited from this office.
Date: January 1, 1981
Creator: /NBM--6011986, DOE
Partner: UNT Libraries Government Documents Department
open access

Focal Plane Metrology for the LSST Camera

Description: Meeting the science goals for the Large Synoptic Survey Telescope (LSST) translates into a demanding set of imaging performance requirements for the optical system over a wide (3.5{sup o}) field of view. In turn, meeting those imaging requirements necessitates maintaining precise control of the focal plane surface (10 {micro}m P-V) over the entire field of view (640 mm diameter) at the operating temperature (T {approx} -100 C) and over the operational elevation angle range. We briefly describe the hierarchical design approach for the LSST Camera focal plane and the baseline design for assembling the flat focal plane at room temperature. Preliminary results of gravity load and thermal distortion calculations are provided, and early metrological verification of candidate materials under cold thermal conditions are presented. A detailed, generalized method for stitching together sparse metrology data originating from differential, non-contact metrological data acquisition spanning multiple (non-continuous) sensor surfaces making up the focal plane, is described and demonstrated. Finally, we describe some in situ alignment verification alternatives, some of which may be integrated into the camera's focal plane.
Date: January 10, 2007
Creator: A Rasmussen, Andrew P.; Hale, Layton; Kim, Peter; Lee, Eric; Perl, Martin; Schindler, Rafe et al.
Partner: UNT Libraries Government Documents Department
open access

IN-VIVO DIAGNOSIS OF CHEMICALLY INDUCED MELANOMA IN AN ANIMAL MODEL USING UV-VISIBLE AND NIR ELASTIC SCATTERING SPECTROSCOPY: PRELIMINARY TESTING.

Description: Elastic light scattering spectroscopy (ESS) has the potential to provide spectra that contain both morphological and chromophore information from tissue. We report on a preliminary study of this technique, with the hope of developing a method for diagnosis of highly-pigmented skin lesions, commonly associated with skin cancer. Four opossums were treated with dimethylbenz(a)anthracene to induce both malignant melanoma and benign pigmented lesions. Skin lesions were examined in vivo using both UV-visible and near infrared (NIR) ESS, with wavelength ranges of 330-900 nm and 900-1700 nm, respectively. Both portable systems used identical fiber-optic probe geometry throughout all of the measurements. The core diameters for illuminating and collecting fibers were 400 and 200 {micro}m, respectively, with center-to-center separation of 350 {micro}m. The probe was placed in optical contact with the tissue under investigation. Biopsies from lesions were analyzed by two standard histopathological procedures. Taking into account only the biopsied lesions, UV-visible ESS showed distinct spectral correlation for 11/13 lesions. The NIR-ESS correlated well with 12/13 lesions correctly. The results of these experiments showed that UV-visible and NIR-ESS have the potential to classify benign and malignant skin lesions, with encouraging agreement to that provided by standard histopathological examination. These initial results show potential for ESS based diagnosis of pigmented skin lesions, but further trials are required in order to substantiate the technique.
Date: January 1, 2001
Creator: A'AMAR, C.; LEY, R. & AL, ET
Partner: UNT Libraries Government Documents Department
open access

Comparison of ICEPEL predictions with single elbow flexible piping system experiment

Description: The ICEPEL Code for coupled hydrodynamic-structural response analysis of piping systems is used to analyze an experiment on the response of flexible piping systems to internal pressure pulses. The piping system consisted of two flexible Nickel-200 pipes connected in series through a 90/sup 0/ thick-walled stainless steel elbow. A tailored pressure pulse generated by a calibrated pulse gun is stabilized in a long thick-walled stainless steel pipe leading to the flexible piping system which ended with a heavy blind flange. The analytical results of pressure and circumferential strain histories are discussed and compared against the experimental data obtained by Stanford Research Institute.
Date: January 1, 1978
Creator: A-Moneim, M.T. & Chang, Y.W.
Partner: UNT Libraries Government Documents Department
open access

Computer simulation of LMFBR piping systems. [Accident conditions]

Description: Integrity of piping systems is one of the main concerns of the safety issues of Liquid Metal Fast Breeder Reactors (LMFBR). Hypothetical core disruptive accidents (HCDA) and water-sodium interaction are two examples of sources of high pressure pulses that endanger the integrity of the heat transport piping systems of LMFBRs. Although plastic wall deformation attenuates pressure peaks so that only pressures slightly higher than the pipe yield pressure propagate along the system, the interaction of these pulses with the different components of the system, such as elbows, valves, heat exchangers, etc.; and with one another produce a complex system of pressure pulses that cause more plastic deformation and perhaps damage to components. A generalized piping component and a tee branching model are described. An optional tube bundle and interior rigid wall simulation model makes such a generalized component model suited for modelling of valves, reducers, expansions, and heat exchangers. The generalized component and the tee branching junction models are combined with the pipe-elbow loop model so that a more general piping system can be analyzed both hydrodynamically and structurally under the effect of simultaneous pressure pulses.
Date: January 1, 1977
Creator: A-Moneim, M.T.; Chang, Y.W. & Fistedis, S.H.
Partner: UNT Libraries Government Documents Department
open access

Quadratic electroweak corrections for polarized Moller scattering

Description: The paper discusses the two-loop (NNLO) electroweak radiative corrections to the parity violating electron-electron scattering asymmetry induced by squaring one-loop diagrams. The calculations are relevant for the ultra-precise 11 GeV MOLLER experiment planned at Jefferson Laboratory and experiments at high-energy future electron colliders. The imaginary parts of the amplitudes are taken into consideration consistently in both the infrared-finite and divergent terms. The size of the obtained partial correction is significant, which indicates a need for a complete study of the two-loop electroweak radiative corrections in order to meet the precision goals of future experiments.
Date: January 1, 2012
Creator: A. Aleksejevs, S. Barkanova, Y. Kolomensky, E. Kuraev, V. Zykunov
Partner: UNT Libraries Government Documents Department
open access

Development and evaluation of systems for controlling parallel high di/dt thyratrons

Description: Increasing numbers of high power, high repetition rate applications dictate the use or thyratrons in multiple of hard parallel configurations to achieve the required rate of current rise, di/dt. This in turn demands the development of systems to control parallel thyratron commutation with nanosecond accuracy. Such systems must be capable of real-time, fully-automated control in multi-kilohertz applications while still remaining cost effective. This paper describes the evolution of such a control methodology and system.
Date: January 1, 1982
Creator: A., Litton. & McDuff, G.
Partner: UNT Libraries Government Documents Department
open access

ORGDP Container Test and Development Program Fire Tests of UF6-Filled Cylinders

Description: Fire tests of bare, UF{sub 6}-filled shipping cylinders were conducted at the ORGDP Rifle Range during October 1965 as part of the AEC-ORO Container Test and Development Program presently under way at the ORGDP. The multi purpose effort was to determine if the cylinders would hydrostatically or explosively rupture; the time available for fire fighting before either incident occurred; and the degree of contamination as related to the type of UF{sub 6} release, wind velocity, and terrain. In addition to the cylinder fire tests, other tests were made for further evaluation of the fire-resistant BOX foam plastic. These included a newly designed shipping drum for 5-in.-diam cylinders, and 15B-type wood shipping boxes for small containers. In one case, the latter contained a UF{sub 6}-filled Harshaw cylinder. The test times ranged from 45 to 95 min. In no instance did temperatures exceed 200 F These tests are discussed under Part B. Our Nuclear Engineering Department was responsible for site preparation and the test program. The Safety and Health Physics Departments Mr. A. F. Becher, head, provided primary assistance in the conductance of the tests and was additionally responsible for the environmental monitoring and sampling. Personnel of the Plant Shift Operations and Security, Fabrication and Maintenance, and Technical Divisions provided further support in the various operations. Mr. J. E. Wescott of the AEC-ORO and Mr. J. W. Edwards, ORGDP, were in charge of the motion and still photography. Two each of the following types of cylinders were tested: 3.5 in. diam x 7.5 in. Monel Harshaw, 5.0 in, diam x 30 in. Monel, and 8 in. diam x 48 in. nickel. Fill limits were 5, 55, and 250 lb of UF{sub 6} respectively, at an enrichment level of 0.22%. The larger cylinders were tested individually, with and without their metal valve covers. …
Date: January 12, 1966
Creator: A.J., Mallett
Partner: UNT Libraries Government Documents Department
open access

HIGH ALUMINUM HLW (HIGH LEVEL WASTE ) GLASSES FOR HANFORDS WTP (WASTE TREATMENT PROJECT)

Description: This paper presents the results of glass formulation development and melter testing to identify high waste loading glasses to treat high-Al high level waste (HLW) at Hanford. Previous glass formulations developed for this HLW had high waste loadings but their processing rates were lower that desired. The present work was aimed at improving the glass processing rate while maintaining high waste loadings. Glass formulations were designed, prepared at crucible-scale and characterized to determine their properties relevant to processing and product quality. Glass formulations that met these requirements were screened for melt rates using small-scale tests. The small-scale melt rate screening included vertical gradient furnace (VGF) and direct feed consumption (DFC) melter tests. Based on the results of these tests, modified glass formulations were developed and selected for larger scale melter tests to determine their processing rate. Melter tests were conducted on the DuraMelter 100 (DMIOO) with a melt surface area of 0.11 m{sup 2} and the DuraMelter 1200 (DMI200) HLW Pilot Melter with a melt surface area of 1.2 m{sup 2}. The newly developed glass formulations had waste loadings as high as 50 wt%, with corresponding Al{sub 2}O{sub 3} concentration in the glass of 26.63 wt%. The new glass formulations showed glass production rates as high as 1900 kg/(m{sup 2}.day) under nominal melter operating conditions. The demonstrated glass production rates are much higher than the current requirement of 800 kg/(m{sup 2}.day) and anticipated future enhanced Hanford Tank Waste Treatment and Immobilization Plant (WTP) requirement of 1000 kg/(m{sup 2}.day).
Date: January 4, 2010
Creator: AA, KRUGER; BW, BOWAN; I, JOSEPH; H, GAN; WK, KOT; KS, MATLACK et al.
Partner: UNT Libraries Government Documents Department
open access

MELT RATE ENHANCEMENT FOR HIGH ALUMINUM HLW (HIGH LEVEL WASTE) GLASS FORMULATION FINAL REPORT 08R1360-1

Description: This report describes the development and testing of new glass formulations for high aluminum waste streams that achieve high waste loadings while maintaining high processing rates. The testing was based on the compositions of Hanford High Level Waste (HLW) with limiting concentrations of aluminum specified by the Office of River Protection (ORP). The testing identified glass formulations that optimize waste loading and waste processing rate while meeting all processing and product quality requirements. The work included preparation and characterization of crucible melts and small scale melt rate screening tests. The results were used to select compositions for subsequent testing in a DuraMelter 100 (DM100) system. These tests were used to determine processing rates for the selected formulations as well as to examine the effects of increased glass processing temperature, and the form of aluminum in the waste simulant. Finally, one of the formulations was selected for large-scale confirmatory testing on the HLW Pilot Melter (DM1200), which is a one third scale prototype of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) HLW melter and off-gas treatment system. This work builds on previous work performed at the Vitreous State Laboratory (VSL) for Department of Energy (DOE) to increase waste loading and processing rates for high-iron HLW waste streams as well as previous tests conducted for ORP on the same high-aluminum waste composition used in the present work and other Hanford HLW compositions. The scope of this study was outlined in a Test Plan that was prepared in response to an ORP-supplied statement of work. It is currently estimated that the number of HLW canisters to be produced in the WTP is about 13,500 (equivalent to 40,500 MT glass). This estimate is based upon the inventory of the tank wastes, the anticipated performance of the sludge treatment processes, and current understanding …
Date: January 4, 2010
Creator: AA, KRUGER; KS, MATLACK; W, KOT; IL, PEGG; I, JOSEPH; T, BARDAKCI et al.
Partner: UNT Libraries Government Documents Department
open access

Final Report-Confirmatory Survey Results for the ABB Combustion Engineering Site, Windsor, Connecticut; Revision 1 (DCN 5158-SR-02-1) (Docket No. 030-03754; RFTA No. 12-003)

Description: The objectives of the confirmatory activities were to provide independent contractor field data reviews and to generate independent radiological data for use by the NRC in evaluating the adequacy and accuracy of the contractor�s procedures and FSS results. ORAU reviewed ABB CE�s decommissioning plan, final status survey plan, and the applicable soil DCGLs, which were developed based on an NRC-approved radiation dose assessment. The surveys included gamma surface scans, gamma direct measurements, and soil sampling.
Date: January 28, 2013
Creator: ADAMS, WADE C
Partner: UNT Libraries Government Documents Department
open access

AIDS Care is Health Care

Description: Booklet written by the Aids Action Council arguing for better insurance and healthcare benefits for individuals living with HIV/AIDS and outlining current legislation in favor of these changes.
Date: January 1994
Creator: AIDS Action Council
Partner: UNT Libraries Special Collections
Back to Top of Screen