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.
Z yields jets+. gamma. as a signal for R-parity violation
Supersymmetric models with explicit R-parity violation can induce new rare decay modes of the Z boson into single supersymmetric particles. Here, the rate and signature for one such decay, Z {yields} {tilde {upsilon}} {gamma}, is examined, where it is found that the rate is at least an order of magnitude smaller than that for the process Z{yields} H{gamma}, even with larger values of the R-parity violating couplings.
Date:
February 1, 1992
Creator:
Hewett, J.L.
System:
The UNT Digital Library
Fusion breeder
The fusion breeder is a fusion reactor designed with special blankets to maximize the transmutation by 14 MeV neutrons of uranium-238 to plutonium or thorium to uranium-233 for use as a fuel for fission reactors. Breeding fissile fuels has not been a goal of the US fusion energy program. This paper suggests it is time for a policy change to make the fusion breeder a goal of the US fusion program and the US nuclear energy program. The purpose of this paper is to suggest this policy change be made and tell why it should be made, and to outline specific research and development goals so that the fusion breeder will be developed in time to meet fissile fuel needs.
Date:
February 22, 1982
Creator:
Moir, Ralph W.
System:
The UNT Digital Library
Alloys in energy development
The development of new and advanced energy systems often requires the tailoring of new alloys or alloy combinations to meet the novel and often stringent requirements of those systems. Longer life at higher temperatures and stresses in aggressive environments is the most common goal. Alloy theory helps in achieving this goal by suggesting uses of multiphase systems and intermediate phases, where solid solutions were traditionally used. However, the use of materials under non-equilibrium conditions is now quite common - as with rapidly solidified metals - and the application of alloy theory must be modified accordingly. Under certain conditions, as in a reactor core, the rate of approach to equilibrium will be modified; sometimes a quasi-equilibrium is established. Thus an alloy may exhibit enhanced general diffusion at the same time as precipitate particles are being dispersed and solute atoms are being carried to vacancy sinks. We are approaching an understanding of these processes and can begin to model these complex systems.
Date:
February 1, 1984
Creator:
Frost, B.R.T.
System:
The UNT Digital Library
Photomultiplier characteristics considerations for the deep underwater muon and neutrino detection system
The results of an investigation of the characteristics of photomultipliers for the Deep Underwater Muon and Neutrino Detection (DUMAND) System are discussed. The pulse-height resolution, the afterpulsing phenomena and the gain sensitivity to the ambient magnetic field have been determined for large photocathode area photomultipliers. Furthermore, the transient time difference, the single photoelectron time spread, and the collection and photocathode quantum efficiency uniformity as a function of the position of the photocathode sensing area have been reviewed. Finally, an attempt has been made to estimate the photomultiplier reliability and its lifetime.
Date:
February 23, 1980
Creator:
Leskovar, B.
System:
The UNT Digital Library
The human genome: Computational challenges
The deoxyribonucleic acid (DNA) of a human cell contains all the information required for specifying that cell, or indeed the whole person, and constitues the human genome. Programs are now underway to obtain genetic linkage maps and physical maps of human chromosomes containing the DNA, and large scale efforts will soon begin to provide detailed sequences. The challenges involved in assembling these data into a knowledge base are examined. Computations will play a key role in enabling the scientists to understand the information contained in sequence data. Pattern recognition and string matching algorithms will be of particular importance. Recent results in the use of adaptive networks for pattern detection will be presented. 19 refs.
Date:
February 1, 1988
Creator:
Bell, G.I.
System:
The UNT Digital Library
On the measuremnt of. pi
Inspired by Stillman Drake's definition of Galilean Units as those for which (L/T{sup 2} = ({pi}{sup 2}/8)g) where g is any finite, constant acceleration measured in units of L and T, we construct a kinematical dimensional analysis based only on two universal, dimensionless constants. For the linear relation between L and T we use Einsteinian Units L/ = (1)c. For orbiting masses negligible compared to some mass unit M, we use Keplerian Units based on his second law (L{sup 2}/T = (1/2{pi})h/M). Then the unit for orbital angular momentum is {Dirac h}, independent of the mass scale. This allows us to define dimensionless coupling constants f{sup 2} = {beta} = v/c where v is the orbital velocity. We find that most of relativistic quantum mechanics requires only kinematical units. Dynamical units require a mass scale with universal significance, set by the orbital velocity v = c (or f{sup 2} = 1). In dimensional form this becomes M = (1)({Dirac h}c/G){sup 1/2}. Assuming baryon number conservation, the fact that the proton is the lightest stable baryon allows us to calculate {Dirac h}c/Gm{sub p}{sup 2} {approx} 1.7 {times} 10{sup 38} as the Beckenstein number of the proton--the number of bits of information …
Date:
February 1, 1992
Creator:
Noyes, H. Pierre
System:
The UNT Digital Library
Radiological design criteria for fusion power test facilities
The quest for fusion power and understanding of plasma physics has resulted in planning, design, and construction of several major fusion power test facilities, based largely on magnetic and inertial confinement concepts. We have considered radiological design aspects of the Joint European Torus (JET), Livermore Mirror and Inertial Fusion projects, and Princeton Tokamak. Our analyses on radiological design criteria cover acceptable exposure levels at the site boundary, man-rem doses for plant personnel and population at large, based upon experience gained for the fission reactors, and on considerations of cost-benefit analyses.
Date:
February 12, 1982
Creator:
Singh, M.S. & Campbell, G.W.
System:
The UNT Digital Library
Paleomagnetism of the Quaternary Cerro Prieto, Crater Elegante, and Salton Buttes volcanic domes in the northern part of the Gulf of California rhombochasm
Deviating thermomagnetic directions in volcanics representing the second and fifth or sixth pulse of volcanism suggest that the Cerro Prieto volcano originated about 110,000 years B.P. and continued to be active intermittently until about 10,000 years ago.
Date:
February 1, 1980
Creator:
de Boer, J.
System:
The UNT Digital Library
An alternate end design for SSC dipoles
Experience in the SSC dipole program has shown that fabrication of cylindrical coil ends is difficult. Cable stiffness requires large forces to maintain the proper position of the conductors in the end during winding. After winding, the coil ends remain distorted nd significant motion of the need conductors is required to force the coil end into the molding cavity. Local mechanical stresses are high during this process and extra pieces of insulation are required to prevent turn-to-turn shorts from developing during the winding and molding steps. Prior to assembly the coil end is compressed in a mold cavity and injected with a filler material to correct surface irregularities and fill voids in the end. LBL has developed an alternate design which permits the conductors to be wound over the end using minimal force and technician coerosion. The conductors are placed on a conical surface where the largest diameter over the outer layer conductors is 10 cm. No coil end spaces or insulation pieces between turns are required. The conductor geometry was analytically optimized to meet SSC multipole requirements for the ends. The first 1-m dipole utilizing this end geometry has been constructed and successfully tested. Design and construction data are …
Date:
February 1, 1989
Creator:
Peters, C.; Caspi, S. & Taylor, C.
System:
The UNT Digital Library
Proceedings of the US Nuclear Regulatory Commission fifteenth water reactor safety information meeting: Volume 6, Decontamination and decommissioning, accident management, TMI-2
This six-volume report contains 140 papers out of the 164 that were presented at the Fifteenth Water Reactor Safety Information Meeting held at the National Bureau of Standards, Gaithersburg, Maryland, during the week of October 26-29, 1987. The papers are printed in the order of their presentation in each session and describe progress and results of programs in nuclear safety research conducted in this country and abroad. This report, Volume 6, discusses decontamination and decommissioning, accident management, and the Three Mile Island-2 reactor accident. Thirteen reports have been cataloged separately.
Date:
February 1, 1988
Creator:
Weiss, A. J.
System:
The UNT Digital Library
Precision Gravity Studies at Cerro Prieto: The Second Year
Precision gravity measurements were initiated at Cerro Prieto in 1978. Interpretation of the first annual repetition of the measurements is presented. Field procedures, data reduction, and data interpretation are reviewed briefly. (MHR)
Date:
February 1, 1980
Creator:
Grannell, R. B.; Tarman, D. W.; Clover, R. C.; Leggewie, R. M.; Aronstam, P. S.; Kroll, R. C. et al.
System:
The UNT Digital Library
High-temperature geothermal reservoir engineering
A review of high-temperature geothermal reservoir engineering is presented. High-temperature downhole conditions encountered during field activities are reviewed with data from Cerro Prieto as the primary example. The types of measurements required for estimation of formation parameter values and how they depend on other geoscience data are reviewed. The analysis techniques that are currently used to evaluate field data are discussed and their limitations, applicability, and associated difficulties are described using data from Cerro Prieto as an example. Downhole tools that are needed for high-temperature measurements are discussed with a review of the current state of the art. The use of measured data in reservoir engineering simulation calculations is summarized, and different numerical models are reviewed. Data from Cerro Prieto are used as an example to show how reserves and reservoir depletion calculations can be used to aid the field developer in choosing operational field strategies.
Date:
February 1, 1980
Creator:
Schroeder, R.C.; Benson, S. & Goranson, C.
System:
The UNT Digital Library
650 mm long liquid hydrogen target for use in a high intensity electron beam
This paper describes a 650 mm long liquid hydrogen targetr constructed for use in the high intensity electron beam at the Stanford Linear Accelerator Center (SLAC). The main design problem was to construct a target that would permit the heat deposited by the electron beam to be removed rapidly without boiling the hydrogen so as to maintain constant target density for optimum data taking. Design requirements, cosntruction details and operating experience are discussed.
Date:
February 1, 1984
Creator:
Mark, J.W.
System:
The UNT Digital Library
Combined gettering and molten salt process for tritium recovery from lithium
A new tritium recovery concept from lithium has been developed as part of the US/Japan collaboration on Reversed-Field Pinch Reactor Design Studies. This concept combines the ..gamma..-gettering process as the front end to recover tritium from the coolant, and a molten salt recovery process to extract tritium for fuel processing. A secondary lithium is used to regenerate the tritium from the gettering bed and, in the process, increases the tritium concentration by a factor of about 20. That way, the required size of the molten salt process becomes very small. A potential problem is the possible poisoning of the gettering bed by the salt dissolved in lithium. 16 refs., 6 figs.
Date:
February 1, 1988
Creator:
Sze, D.K.; Finn, P.A.; Bartlit, J.; Tanaka, S.; Teria, T. & Yamawaki, M.
System:
The UNT Digital Library
Theory of the temperature dependence of positron bulk lifetimes-implications for vacancy formation enthalpy measurements via positron experiments
Temperature dependent effects, which may have a bearing on determinations of vacancy formation enthalpies in metals by positron annihilation, have been observed in certain metals. These effects have been observed to occur both at temperatures below those at which positron annihilation is most sensitive to equilibrium vacancies and at temperatures well within the vacancy-sensitive region. The effect of thermal lattice displacements on positron lifetimes in metals was investigated to help understand these phenomena. (GHT)
Date:
February 1, 1977
Creator:
Tam, S.W.; Sinha, S.K. & Siegel, R.W.
System:
The UNT Digital Library
Diffusion welding multifilament superconductive composites
Diffusion welding is shown to be a feasible method for joining composites of niobium-titanium superconductor alloy filaments in a pure copper matrix. Good results were repeatedly obtained using 15/sup 0/ scarf joints welded with externally heated tooling and simple uniaxial compression loading in a conventional hydraulic press. Weld cycles of less than one hour total elapsed time were readily attainable. Through proper closed-die design, it was possible to increase welding pressure sufficiently to use relatively low temperatures to coincide with the optimum aging heat treatment of the superconductor alloy. This temperature limitation is important to retain optimal superconductor properties. Confirming measurements of critical current density of welded joints at 4.2/sup 0/K are in progress. In the welded joints made under optimum conditions, there is bonding of all constituents, including superconductor filaments. Weld tooling which effectively contains the relatively fluid matrix, and resists deformation during repeated weld cycles, is essential to the successful application of the diffusion welding process to these composites.
Date:
February 27, 1978
Creator:
Witherell, C.E.
System:
The UNT Digital Library
Heat exchanger design considerations for high temperature gas-cooled reactor (HTGR) plants
Various aspects of the high-temperature heat exchanger conceptual designs for the gas turbine (HTGR-GT) and process heat (HTGR-PH) plants are discussed. Topics include technology background, heat exchanger types, surface geometry, thermal sizing, performance, material selection, mechanical design, fabrication, and the systems-related impact of installation and integration of the units in the prestressed concrete reactor vessel. The impact of future technology developments, such as the utilization of nonmetallic materials and advanced heat exchanger surface geometries and methods of construction, is also discussed.
Date:
February 1980
Creator:
McDonald, C. F.; Vrable, D. L.; Van Hagan, T. H.; King, J. H. & Spring, A. H.
System:
The UNT Digital Library
Toxicologic studies of SRC materials
Investigations on the toxicity of SRC materials are reported. Toxicological studies include: microbial mutageneis (Ames test); in vitro mammalian cell toxicity and transformation assays; epidermal carcinogenesis (skin painting); acute and subchronic oral toxicity; developmental toxicity; dominant lethal assays; inhalation toxicity; and dosimetry and metabolism. The materials tested include: SRC-I process solvent, wash solvent, and light oil; SRC-II heavy distillate, middle distillate, and light distillate; shale oil; crude petroleum; and pure carcinogens. (DC)
Date:
February 1, 1980
Creator:
Mahlum, D. D.; Pelroy, R. A.; Drucker, H.; Wilson, B. W.; Massey, M. J. & Schmalzer, D. K.
System:
The UNT Digital Library
A high-fluence fusion neutron source
A conceptual design of a D-T fusion facility for continuous production of 14-MeV neutron wall loading from 5 to 10 MW/m/sup 2/ at the plasma surface is presented. In this design, D-T neutrons are produced in a linear, two-component plasma formed by neutral beam irradiation of a fully ionized warm plasma target. The beam energy, which is deposited in the center, is transferred to the warm plasma mainly by electron drag and is conducted along the target plasma column to end regions where it is absorbed in neutral gas at high pressure. The target plasma is operated in a regime where electron thermal conduction along the column is the controlling energy-loss process. The loss rate is minimized by adjusting the diameter and length of the plasma column. A substantial gradient in T/sub e/ along the column results in recombination of the plasma to gas in the end-regions before impact on the end walls. The resultant hot gas is cooled by contact with large-area heat exchangers. In this way, the large steady-state heat load from the injected neutral beams is diffused and removed at tolerable heat flux levels. The reacting plasma is essentially an extrapolation of the 2XIIB high-..beta.. plasma to …
Date:
February 17, 1988
Creator:
Coensgen, F. H.; Casper, T. A.; Correll, D. L.; Damm, C. C.; Futch, A. H.; Logan, B. G. et al.
System:
The UNT Digital Library
Influence of surface silica impurities on the sintering behavior of alumina powders
The filtering, pressing and sintering behavior of an alumina powder with and without silica impurity on surface has been studied. When silica is removed from surface by HF-treatment and compactibility is considerably enhanced due to the different acidity/basicity nature of the OH of the hydroxyl layers. The silica impurity decreases the activation energy of the initial stage of sintering and grain boundary energy, improves the densification process and exerts a moderate inhibitor effect on the grain growth.
Date:
February 1, 1980
Creator:
Moya, J.S. & Pask, J.A.
System:
The UNT Digital Library
Decision-making and radiological protection at Three Mile Island: response of the Department of Health, Education and Welfare
Decision-making by decision-makers during the nuclear accident at Three Mile Island all had to do in some way, and impacted on the public health and safety, the health and safety of the workers, and emergency preparedness and health care. This paper reviews the activities of only one federal agency during the accident, the Department of Health, Education, and Welfare (HEW), and its effectiveness in its role as the leading institution responsible for protecting the public health during the first accident in a nuclear power plant designed for the commerical generation of electricity in the United States. My comments are limited to only three acts dealing with radiological health and protection: the struggle for power and assertion of leadership in response to possible health consequences of the accident; the decisions to evacuate the area during the radiological emergency; and the use of potassium iodide as a means of protecting the public and the workers from the hazards of exposure to radioactive iodine released to the environment.
Date:
February 1, 1982
Creator:
Fabrikant, Jacob I.
System:
The UNT Digital Library
RF Energy Compressor
The RF Energy Compressor, REC described here, transforms cw rf into periodic pulses using an energy storage cavity, ESC, whose charging is controlled by 180/sup 0/ bi-phase modulation, PSK, and external Q switching, ..beta..s. Compression efficiency, C/sub e/, of 100% can be approached at any compression factor C/sub f/.
Date:
February 1, 1980
Creator:
Farkas, Z. D.
System:
The UNT Digital Library
Electromagnetic Effects in Relativistic Electron Beam Plasma Interactions
Electromagnetic effects excited by intense relativistic electron beams in plasmas are investigated using a two-dimensional particle code. The simulations with dense beams show large magnetic fields excited by the Weibel instability as well as sizeable electromagnetic radiation over a significant range of frequencies. The possible relevance of beam plasma instabilities to the laser acceleration of particles is briefly discussed. 6 refs., 4 figs.
Date:
February 13, 1985
Creator:
Kruer, W. L. & Langdon, A. B.
System:
The UNT Digital Library
3-body final states in peripheral heavy-ion collisions: nuclear clustering structure and projectile excitation revisited
Even though peripheral heavy-ion collisions are less violent than their central counterparts, the large energy exchange between the reactants often leaves the primary products in excited particle-unstable states whose subsequent decay leads to 3 or more nuclei emerging in the final exit channel. These post-reaction, predominantly sequential de-excitation processes can sometimes provide interesting structural information about the parent nuclei. In fact, provided these processes are well understood, one can employ them as probes for studying initial properties of the fragments. This report discusses results of two experiments that deal with (1) nonstatistical, rare decay modes of the projectile, and (2) internal excitation energy of the projectile- and target-like fragments in peripheral collisions. The physics addressed in each is different, but the experimental and data-analysis techniques are so similar that it is relevant to join them together.
Date:
February 1, 1986
Creator:
Chan, Y.; Chavez, E.; Gazes, S.B.; Kamermans, R.; Schmidt, H.R.; Siwek-Wilczynska, J. et al.
System:
The UNT Digital Library