Resource Type
Partner
UNT Libraries Government Documents Department
5,884
UNT College of Arts and Sciences
150
UNT College of Science
71
UNT College of Engineering
39
UNT Libraries Special Collections
13
UNT Libraries
12
UNT College of Education
12
UNT College of Liberal Arts & Social Sciences
9
UNT Health Science Center
7
University of North Texas
7
13 More
Collection
Office of Scientific & Technical Information Technical Reports
5,882
UNT Scholarly Works
321
UNT Graduate Student Works
5
Multicultural Center Records
5
D. Jack Davis Art Education Collection
3
LGBT Collections
3
Abilene Library Consortium
2
Dennis Vercher Collection (The Dallas Way)
2
End of Term Publications
2
Rescuing Texas History, 2014
2
9 More
Degree Department
Decade
Month
6,230 Matching Results
Results open in a new window/tab.
Results:
1 - 24 of
6,230
next
First wall/blanket/shield design and optimization system
First wall/blanket/shield design and optimization system (BSDOS) has been developed to provide a state-of-the-art design tool for fast accurate analysis. In addition, it has been designed to perform several other functions: (1) allowing comparison and evaluation studies for different concepts using the same data bases and ground rules, (2) permitting the use of any figure of merit in the evaluation studies, (3) optimizing the first wall/blanket/shield design parameters for any figure of merit under several design constraints, (4) permitting the use of different reactor parameters in the evaluation and optimization analyses, (5) allowing the use of improved eingineering data bases to study the impact on the design performance for planning future research and development, and (6) evaluating the effect of the data base uncertainties on the design performance. BSDOS is the first design and optimization system to couple the highly interacting neutronics, heat transfer, thermal hydraulics, stress analysis, radioactivity and decay-heat analyses, tritium balance, and capital cost. A brief description of the main features of BSDOS is given in this paper. Also, results from using BSDOS to perform design analysis for several reactor components are presented. 17 refs., 1 fig., 2 tabs.
Date:
February 1, 1988
Creator:
Gohar, Y.; Baker, C.; Attaya, H.; Cha, Y.; Majumdar, S. & Scandora, T.
System:
The UNT Digital Library
Modeling studies on the precipitation of Kr after implantation into metals
A rate-theory approach is applied to interpreting observations on the precipitation of Kr injected into Ni at temperatures between 25 and 560/degree/C. At temperatures of 400/degree/C or higher, the implanted Kr precipitates evolve into a bi-modal size distribution containing small solid precipitates and an additional population of larger, faceted bubbles. The calculations explore the dependence of the observed bi-modal distribution on the maximum size of the solid Kr precipitates and the effect of this dependence on bubble mobility. The analysis suggests that during the irradiation, whereas the large bubbles move by surface diffusion, the solid Kr precipitates are immobile. The relevance of the Kr-Ni interaction on the solid Kr precipitates size cutoff is discussed. 18 refs., 8 figs., 2 tabs.
Date:
February 1, 1988
Creator:
Rest, J.
System:
The UNT Digital Library
EPICS System: An Overview
This paper presents an overview of the EPICS control system at FERMILAB. EPICS is a distributed, multi-user, interactive system for the control and monitoring of particle beamlines at a high-energy experimental physics laboratory. The overview discusses the operating environment of the control system, the requirements which determined the design decisions, the hardware and software configurations, and plans for the future growth and enhancement of the present system. This paper is the first of three related papers on the EPICS system. The other two cover (1) the system structure and user interface and (2) RSX implementation issues.
Date:
February 1, 1984
Creator:
Bartlett, J. F.; Bobbitt, J. S.; Kramper, B. J.; Lahey, T. E.; MacKinnon, B. A. & West, R. E.
System:
The UNT Digital Library
Statistical fluctuations in heavy-ion collisions
The relevance of the statistical equilibrium limit to the description of substantially relaxed degrees of freedom is discussed. Fluctuations are considered specifically in the following processes: the correlation between entrance-channel angular momentum and exit-channel kinetic energy; the sharing of the dissipated kinetic energy between the two fragments; the magnitude and the alignment of the fragment angular momentum including the effect of shell structure. It is found that statistical fluctuations play a major role and that the statistical equilibrium limit seems to have been reached for a number of degrees of freedom.
Date:
February 1, 1982
Creator:
Moretto, Luciano G.
System:
The UNT Digital Library
Fusion energy development: Breakeven and beyond: Keynote address
The scientific feasibility, technological inevitability, and economic necessity of fusion as an energy source are discussed.
Date:
February 1, 1988
Creator:
Furth, H.P.
System:
The UNT Digital Library
Ceramic microstructures and their elucidation by imaging, diffraction and spectroscopic methods
The development and potential utilization of ceramic materials is dependent on a systematic effort involving processing, characterization and appropriate property measurements. The methods of characterization are numerous and it is important to employ the one that is appropriate to the problem both in terms of its information content and the achievable level of resolution. With the incorporation of fine probe forming capabilities in a transmission electron microscope and the development of related diffraction, imaging and spectroscopic methods, it is now possible to obtain structural and chemical information from the same region of the sample at high spatial resolution. In this review, recent advances along with representative examples in the application of high resolution electron microscopy (HREM), convergent beam electron diffraction (CBED), low atomic number element microanalysis by x-ray emission spectroscopy (XES), fine structures in electron energy-loss spectroscopy (EELS) and specific site occupancy determination by channeling experiments are discussed.
Date:
February 1, 1992
Creator:
Kirshnan, K.M.
System:
The UNT Digital Library
The safety record at the tritium systems test assembly
This work addresses an important objective of the TSTA-demonstrating that the large tritium inventories required for fusion reactors can be routinely handled, without radiation exposure to operating personnel and without significant environemtnal releases. The techniques by which TSTA has achieved low releases and personnel exposures include high-integrity primary piping systems that exclude contact between tritium and organic materials, a secondary containment system that encloses all primary tritium piping in a controlled environment, an efficient, all-purpose tritium waste-treatment plant with 100% availability, and ultrasensitive, real-time diagnostics for anticipating and preventing releases, and for detection and location of tritium leaks in a low-risk mode. 5 refs., 11 figs., 2 tabs.
Date:
February 1, 1988
Creator:
Coffin, D.O.
System:
The UNT Digital Library
Blanket technology experiments at Argonne National Laboratory
Argonne National Laboratory has the largest US program for the development of blanket technology. The goals of the program are to resolve critical issues for different blanket concepts, to develop the understanding and predictive capability of blanket behavior, and to develop the technology needed to build and operate advanced fusion blankets. The projects within the program are liquid metal MHD, breeder neutronics, tritium oxidation, transient electromagnetics, FLIBE chemistry, and insulator coatings. The present status and recent results of the projects are described.
Date:
February 1, 1988
Creator:
Mattas, R. F.; Reed, C. B.; Picologlou, B.; Finn, P.; Clemmer, R.; Porges, K. et al.
System:
The UNT Digital Library
Silicon mass transfer in sodium loops and the resulting/thermal hydraulic effects. [LMFBR]
The element silicon in the surface of new, 300 series stainless steel has been shown to rapidly dissolve in sodium above 525/sup 0/C. It deposits in slightly cooler regions as a crystalline compound with sodium and oxygen. In tests, the deposits have caused increases in hydraulic friction factor (hence, increased pressure loss) of up to 300% at Reynolds Numbers of 14/sup 4/ to 10/sup 5/.Also, they have contributed to local losses of heat transfer rate to 1/10 the original value, at a Reynolds Number of approximately 10/sup 4/. The crystals quickly decompose when out of sodium. Measurements made with a sodium loop (volume = 0.42 m/sup 3/) include compound solubility vs temperature, loop conditions vs source rates and deposit transfer rates. Laboratory examinations and analyses of the crystals have also been made. The effects of this material have been observed also in a number of other loops. With the data from these studies, such effects are now explained and can be controlled or eliminated by system design and operation.
Date:
February 1, 1980
Creator:
Yunker, W.H.
System:
The UNT Digital Library
Gamma rays from Cygnus X-1: Modeling and nonthermal pair production
The gamma-ray bump observed between 0.5 and 2 MeV in the spectrum of Cygnus X-1 can be interpreted as the thermal emissions from a hot (kT)approximately)400 keV) pair-dominated cloud. We argue that the X-rays and gamma rays are produced in separate emission regions, and calculate the photon-photon pair production rate from X-ray and gamma-ray interactions in the vicinity of Cyg X-1 by employing a simplified geometry for the two emitting regions.
Date:
February 1, 1988
Creator:
Dermer, C. D. & Liang, E. P.
System:
The UNT Digital Library
Nondestructive evaluation of LWR spent fuel shipping casks
An analysis of nondestructive testing (NDT) methods currently being used to evaluate the integrity of Light Water Reactor (LWR) spent fuel shipping casks is presented. An assessment of anticipated NDT needs related to breeder reactor cask requirements is included. Specific R and D approaches to probable NDT problem areas such as the evaluation of austenitic stainless steel weldments are outlined.
Date:
February 1, 1978
Creator:
Ballard, D. W.
System:
The UNT Digital Library
Presence of UV-endonuclease sensitive sites in daughter DNA of UV-irradiated mammalian cells. [3H-thymidine tracer]
Asynchronous Chinese hamster cells were irradiated with 10 Jm/sup -2/ uv radiation and 0.25 to 4 hours later pulse-labeled with (/sup 3/H)thymidine. Cells synchronized by shaking off mitotic and G/sub 1/ cells were irradiated in either the G/sub 1/-phase or S-phase of the cell cycle and pulse-labeled with (/sup 3/H)thymidine in the S-phase. After a 12 to 14 hour chase in unlabeled medium, the DNA was extracted, incubated with Micrococcus luteus uv-endonuclease and sedimented in alkaline sucrose. The number of endonuclease sensitive sites decreased as the time between uv irradiation and pulse-labeling of daughter DNA increased. Further, there were significantly less endonuclease sensitive sites in the daughter DNA from cells irradiated in the G/sub 1/-phase than in the S-phase. These data indicate that very few, if any, dimers are transferred from parental DNA to daughter DNA and that the dimers detected in daughter DNA may be due to the irradiation of replicating daughter DNA before labeling.
Date:
February 1, 1978
Creator:
D'Ambrosio, S. & Setlow, R.B.
System:
The UNT Digital Library
Existence of fcc TiCr/sub 1/ /sub 8/H/sub 5/ /sub 3/
Originally an orthorhombic structure was assigned to the non-stoichiometric hydride TiCr/sub 1/ /sub 8/H/sub 3/ /sub 6/. Recent neutron and x-ray diffraction data indicated, however, that an alternate interpretation was possible, i.e. the solid consists of two hydride phases, an ..cap alpha..' Laves phase having a composition of TiCr/sub 1/ /sub 8/H/sub 2/ /sub 8/ and an fcc phase with a much higher hydrogen content. This proved to be the case and it has been determined that the high concentration phase has a disordered fluorite structure with a/sub o/=4.27 A. Its hydrogen content, as estimated from diffraction peak intensities, corresponds to TiCr/sub 1/ /sub 8/H/sub 5/ /sub 3/. We have not been able to produce single phase fcc material but have prepared a mixed phase sample with an overall composition of TiCr/sub 1/ /sub 8/H/sub 4/ /sub 8/. The high-pressure reaction leading to the formation of the fluorite phase is very sluggish and irreversible. Pressure-composition-temperature (p-c-T) properties of this system have been determined and are discussed and a revised phase diagram is proposed.
Date:
February 1, 1982
Creator:
Johnson, J. R.; Reilly, J. J.; Reidinger, F.; Corliss, L. M. & Hastings, J. M.
System:
The UNT Digital Library
The hole of a blanket tritium system on the fusion fuel cycle
The requirements of tritium technology are centered in three main areas, i.e., (1) fuel processing, (2) breeder tritium extraction, and (3) tritium containment. The gaseous tritium stream from the breeder tritium extraction system is significantly different from the plasma exhaust stream and, therefore, may have important impact on the operation of the fuel processing system. For some blankets, such as aqueous solution blanket, the blanket tritium stream may dominate the fuel processing system in terms of component size and power consumption. The importance of the blanket interface to a fuel processing experiment, such as TSTA, has been identified. The initial work to define the blanket processing system, which is proposed to be added as part of TSTA, will be discussed here.
Date:
February 1988
Creator:
Sze, D.K.; Finn, P.; Clemmer, R.; Anderson, J.; Bartlit, J.; Naruse, Y. et al.
System:
The UNT Digital Library
Preconcentration of plutonium radionuclides from natural waters. [Pu in Eniwetok ground water, lagoon and open ocean waters]
A large volume water sampler using manganese dioxide impregnated cartridges for the in situ separation of plutonium in sea water and ground water was studied. Plutonium concentrations obtained by this technique are compared with a radiochemical coprecipitation method. Consistent results were obtained between the two methods for water samples from the Pacific Ocean and Enewetak lagoon. Different results were noted from samples collected in the Enewetak reef and ground water stations. Using this preconcentration technique and the coprecipitation method it was shown that the physical-chemical characteristics of Pu in Enewetak reef and ground water are different from the lagoon and open ocean.
Date:
February 1, 1978
Creator:
Wong, K. M.; Nioshkin, V. E. & Jokela, T. A.
System:
The UNT Digital Library
The effective stiffness of nuclei near magic numbers
This paper trys to explain the rapid increase in the apparent size of the rubidium isotope nuclei around the magic number N = 50. Droplet and deformation models are used to evaluate the measured data. 6 refs., 4 figs.
Date:
February 1, 1988
Creator:
Meyers, W.D. & Rozmej, P.
System:
The UNT Digital Library
An HVEM study of displacement cascade damage in Nb/sub 3/Sn at 13 K
TEM images of the martensite structure in Nb/sub 3/Sn were recorded at various temperatures between 12 and 30/degree/K. The transition to the superconducting state was observed by a slight deflection of the electron beam due to a perturbation of the magnetic field of the objective lens at the sample. The primary interest is in irradiation effects due to fast neutrons from a fusion reactor, and therefore ion irradiation conditions that are somewhat comparable to this were selected. These consisted of 50 keV Xe/sup /plus// irradiations to simulate neutron produced cascades in a near surface region and 1.5 Mev Kr/sup /plus// to produce cascade damage through a greater sample thickness. Defect images were obtained as a function of ion dose at 13/degree/K using both fundamental and superlattice dark-field reflections in two-beam conditions. For 50 keV Xe/sup /plus// irradiations at 13/degree/K the defect yields were quite low at low ion doses where individual defect cascades are well separated. At higher ion doses when significant cascade overlap is present, defect density and contrast became greater than expected. Annealing to room temperature produced a large increase in defect density. Irradiation by 1.5 MeV Kr/sup /plus// at 15/degree/K removed the martensite structure by an ion …
Date:
February 1, 1988
Creator:
Kirk, M. A.; Baker, M. C.; Kestel, B. J.; Weber, H. W. & Kampwirth, R. T.
System:
The UNT Digital Library
Design analysis and optimization of self-cooled lithium blankets and shields
A study of self-cooled lithium blankets was carried out to define the performance of these blankets and to determine the potential to operate at the maximum possible values of the performance parameters. The main design parameters considered during the course of the study were the tritium breeding ratio, the blanket energy multiplication factor, the energy fraction lost to the shield, the total blanket thickness, the reflector material selection, and the compositions of the different blanket zones. Another study was carried out to determine materials, compositions, arrangements, and thickness of the shield zone for the reference blanket. Helium and water-cooled shields were optimized for the inboard and outboard sections of the reactor. Based on the above two studies, the reference blanket and shield configurations were developed for the ANL Tokamak Power Systems Study. The helium-cooled shield was selected for use with liquid metal blankets to reduce safety concerns related to lithium-water reactivity. This helium-cooled shield provides shielding characteristics similar to a conventional water-cooled shield. The analyses and results from these studies are the subject of this paper. 12 refs., 4 figs., 2 tabs.
Date:
February 1, 1988
Creator:
Gohar, Y.
System:
The UNT Digital Library
Evaluation of soil damping techniques used in soil structure interaction analysis of a nuclear power plant
A prediction of dynamic soil properties at the site of a nuclear power plant plays a very important role in the seismic analysis of the facility. Conventional modal analysis procedures can accommodate virtually any range of equivalent elastic soil stiffness which is used to characterize the site. However, high radiation damping associated with energy dissipation in the soil half-space is difficult to accommodate in an elastic modal solution to the dynamic problem. Several methods are available to combine the soil damping with the structural damping in a composite modal damping coefficient. However, even with this convenient representation, the resulting large fractions of critical damping can make modal solutions to the problems suspect. This paper is based on experience gained in this area during studies performed for the Nuclear Regulatory Commission involving seismic analyses of power plants.
Date:
February 24, 1982
Creator:
Nelson, T.A.
System:
The UNT Digital Library
Prediction of electron beam welding spiking tendency
On the basis of measured temperature distributions in electron beam welding cavities it is shown that the vapor pressure force dominates in the lower region and the surface tension in the upper region. The region where these two forces are approximately equal is unstable and the surface tension force causes inward flow of liquid metal which tends to form a projection. For a specific material this projection location was found to depend on cavity depth. By postulating that the formation of liquid metal projections at this location results in cavity instabilities, a physical model for predicting when spiking would occur was purposed. A procedure then developed for determining the spiking tendency for a specified material and set of weld parameters is described.
Date:
February 1, 1978
Creator:
Schauer, D. A. & Geidt, W. H.
System:
The UNT Digital Library
The IGAC activity for the development of global emissions inventories: Description and initial results
Modeling assessments of the atmospheric chemistry, air quality and climatic conditions of the past, present and future require as input inventories of emissions of the appropriate chemical species constructed on appropriate spatial and temporal scales. The task of the Global Emissions Inventories Activity (GEIA) of the International Global Atmospheric Chemistry Project (IGAC) is the production of global inventories suitable for a range of research applications. Current GEIA programs are generally based on addressing emissions by species; these include CO{sub 2}, NH{sub 3}/N{sub 2}O, SO{sub 2}/NO{sub x}, CFC, volatile organic compounds and radioisotopes. In addition a separate program to inventory emissions from biomass burning is also being structured, plus an additional program to address data management issues for all the developing inventories. Program priorities are based on current knowledge and tasks needed to produce the desired inventories. This paper will discuss the different types of global inventories to be developed by the GEIA programs, their key characteristics, and areas to be addressed in the compilation of such inventories. Results of the first GEIA task, a survey of existing inventories and auxiliary data, will be presented. The survey included status assessments for the available inventory information for nineteen different atmospheric species or …
Date:
February 1, 1992
Creator:
Benkovitz, C.M. (Brookhaven National Lab., Upton, NY (United States)) & Graedel, T.E. (AT and T Bell Labs., Murray Hill, NJ (United States))
System:
The UNT Digital Library
Considerations for the use of synchrotron radiation sources to measure sub-keV x-ray photoabsorption cross sections in transmission
Sub-keV x-ray photoabsorption cross section measurements in transmission have been made using synchrotron radiation beam lines on the VUV storage ring at the National Synchrotron Light Source (NSLS) and on the SPEAR storage ring at Stanford. The experimental considerations associated with making absolute measurements are reviewed, along with techniques for resolving difficulties. Suggestions for future measurements are included.
Date:
February 1, 1988
Creator:
Tirsell, K.G. & Del Grande, N.K.
System:
The UNT Digital Library
Condensing economizers: Thermal performance and particulate removal efficiencies
Condensing economizers can be used to increase the thermal efficiency of boilers and furnaces. This project has involved a study of these specifically for application to coal-water mixture fuels although the results can be extended to other fuels. experimental studies to evaluate thermal performance and removal of particulates across indirect contract economizers have been performed. The test arrangement incorporates oil firing with the injection of flyash into the flue gas to simulate coal combustion products. Water sprays into the combustion products are used to achieve variable flue gas moisture content and a variable amount of condensation in the economizers. The economizers are tubular with flue gas on the outside of the tubes. Tube surfaces are plastic coated to prevent corrosion. The gas temperature and condensation profiles through the economizers have been predicted and overall predicted performance has been compared with test results. Mechanisms for particle removal are discussed and predicted removal efficiencies as a functions of particle diameter are presented. It is is shown that inertial impaction is the dominant mechanism and particle removal efficiencies up to 89% have been realized.
Date:
February 1, 1992
Creator:
Butcher, T.A.; Litzke, Wai Lin (Brookhaven National Lab., Upton, NY (United States)) & Park, N. (Stony Brook Scientific, Ltd., Morristown, PA (United States))
System:
The UNT Digital Library
Role of organic soils in the world carbon cycle: problem analysis and research needs
In May 1979, The Institute of Ecology held a workshop to determine the role of organic soils in the global carbon cycle and to ascertain their past, present and future significance in world carbon flux. Wetlands ecologists and soil scientists who participated in the workshop examined such topics as Soils as Sources of Atmospheric CO/sub 2/, Organic Soils, Primary Production and Growth of Wetlands Ecosystems, and Management of Peatlands. The major finding of the workshop is that the organic soils are important in the overall carbon budget. Histosols and Gleysols, the major organic soil deposits of the world, normally sequester organic carbon fixed by plants. They may now be releasing enough carbon to account for nearly 10% of the annual rise in atmospheric content of CO/sub 2/.
Date:
February 1, 1980
Creator:
Armentano, T.V. (ed.)
System:
The UNT Digital Library