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Exploring novel silicon-containing polymers---From preceramic polymers to conducting polymers with nonlinear optical properties (open access)

Exploring novel silicon-containing polymers---From preceramic polymers to conducting polymers with nonlinear optical properties

Several new types of silicon-containing preceramic polymers, i.e., poly(diorganosilacetylene) and poly(diorganosilvinylene) have been synthesized with molecular weights from 10,000 to 120,000. These polymers could be thermally converted to SiC with a moderate to high char yields. Ready solubility and good processability made these types of polymers attractive in their applications to ceramics. The thermal polymerization of diethynyldiphenyl-silane, which was reported in 1968 to afford poly(diphenylsilyldiacetylene) via dehydrogenation, was reinvestigated. Spectroscopic studies showed that the polymer had a structure of polyacetylene type not diacetylene. Diphenyldiethynylgermane and a series of diorganodiethynylsilances were synthesized. These could be polymerized in the presence of MoCl{sub 5} or WCl{sub 6} to afford a soluble, violet material with Mw as high as 108,000. 100 refs., 56 figs., 16 tabs.
Date: October 7, 1991
Creator: Pang, Yi.
Object Type: Report
System: The UNT Digital Library
Low-cost solar array project. Task I. Silicon material. Investigation of the hydrogenation of SiCl/sub 4/ (open access)

Low-cost solar array project. Task I. Silicon material. Investigation of the hydrogenation of SiCl/sub 4/

Reaction kinetic measurements on the hydrochlorination of SiCl/sub 4/ and m.g. silicon metal were last reported as a function of reaction temperature, reactor pressure, H/sub 2//SiCl/sub 4/ ratio and silicon metal particle size distribution, 3 SiCl/sub 4/ + 2 H/sub 2/ + Si reversible 4 SiHCl/sub 3/. The effect of impurities in the m.g. silicon metal on the rate of this reaction has been investigated in this quarter. The m.g. silicon was replaced with high purity, electronic grade silicon metal in the hydrochlorination reaction. With electronic grade Si, the reaction rate was found to be about one order of magnitude slower than those obtained with m.g. silicon metal. These metallic impurities in the m.g. silicon appear to have a catalytic effect. Addition of 5 wt% cuprous chloride to the electronic grade Si mass bed increased the reaction rate to the same level as those obtained with m.g. silicon with 5% CuCl added. The effect of prolonged reaction time on the hydrochlorination reaction was studied. The plan is to run the reaction for long periods of time with the objective of studying the life of the Si mass bed. No significant change in the reaction rate was observed after about 80 …
Date: October 7, 1980
Creator: Mui, J. Y. P. & Seyferth, D.
Object Type: Report
System: The UNT Digital Library
Some Scoping Experiments for a Space Reactor (open access)

Some Scoping Experiments for a Space Reactor

Some scoping experiments were performed to evaluate fuel performance in a lithium heat pipe reactor operating at a nominal 1500K heat pipe temperature. Fuel-coolant and fuel-coolant-clad relationships showed that once a failed heat pipe occurs temperatures can rise high enough so that large concentrations of uranium can be transported by the vapor phase. Upon condensation this uranium would be capable of penetrating heat pipes adjacent to the failed pipe. The potential for propagation of failure exists with UO/sub 2/ and a lithium heat pipe. Changing the composition of the metal of the heat pipe would have only a second order effect on the kinetics of the failure mechanism. Uranium carbide and nitride were considered as potential fuels which are nonreactive in a lithium environment. At high temperatures the nitride would be favored because of its better compatibility with potential cladding materials. Compositions of UN with small additions of YN appear to offer very attractive properties for a compact high temperature high power density reactor.
Date: July 7, 1983
Creator: Alexander, C. A. & Ogden, J. S.
Object Type: Report
System: The UNT Digital Library
Federal Government Health, Education, and Welfare Programs of Assistance to American Indians Residing on Federal Reservations (open access)

Federal Government Health, Education, and Welfare Programs of Assistance to American Indians Residing on Federal Reservations

This report lists and describes federal health, education, and welfare programs available to Native Americans living on federal reservations.
Date: October 7, 1969
Creator: Langone, Stephen A.
Object Type: Report
System: The UNT Digital Library
References to Safeguards, Physical Security, and Related Matters in the Nuclear Non-proliferation Act of 1978 (P.L. 95-242) (open access)

References to Safeguards, Physical Security, and Related Matters in the Nuclear Non-proliferation Act of 1978 (P.L. 95-242)

This report includes tables and excerpts of references to safeguards, physical security, and related matters in the Nuclear Non-proliferation Act of 1978.
Date: July 7, 1978
Creator: Kramer, Donna S. & Donnelly, Warren H.
Object Type: Report
System: The UNT Digital Library
Mineral Resources of the United States Continental Shelf: Some Common Questions (open access)

Mineral Resources of the United States Continental Shelf: Some Common Questions

This report answers some frequently asked questions regarding the mineral resources of the continental shelf of the United States
Date: August 7, 1970
Creator: Siehl, George H.
Object Type: Report
System: The UNT Digital Library
Power of the President to use troops to deal with Disorders arising within the states.1967 (open access)

Power of the President to use troops to deal with Disorders arising within the states.1967

This report is about the President powers to dispatch troops to meet three different type of problems arising in the wake of civil disturbances which interfere with the enforcement of Federal laws.
Date: August 7, 1967
Creator: Small, Norman J.
Object Type: Report
System: The UNT Digital Library
New Approaches to Income Maintenance (open access)

New Approaches to Income Maintenance

This report discusses income maintenance programs and various proposals to reform the system.
Date: January 7, 1970
Creator: Humphreys, Joseph R.
Object Type: Report
System: The UNT Digital Library
The Mexican Farm Labor Program: References, 1951-1965 (open access)

The Mexican Farm Labor Program: References, 1951-1965

This report cites the references related to the Mexican Farm Labor Program.
Date: June 7, 1965
Creator: Heslet, Mary R.
Object Type: Report
System: The UNT Digital Library
An MS-DOS-based program for analyzing plutonium gamma-ray spectra (open access)

An MS-DOS-based program for analyzing plutonium gamma-ray spectra

A plutonium gamma-ray analysis system that operates on MS-DOS-based computers has been developed for the International Atomic Energy Agency (IAEA) to perform in-field analysis of plutonium gamma-ray spectra for plutonium isotopics. The user interacts with the system by means of menus and screens that allow the user to select various applications and to enter information pertinent to a measurement. This information, along with the plutonium weight-percent-abundance results from the data analysis, is stored in dBASE III files. The spectral-data-analysis program, IAEAPU, determines the relative plutonium isotopic abundances from gamma-ray peaks in the 110- to 390-keV region of the spectral data. The program is compact so that it may be used on a portable, battery-operated, laptop, personal computer (PC) that uses a 3-1/2-in. floppy diskette. This is intended to be the final report on this work. We describe in detail the data-analysis methodology, the software, and the operation of the plutonium gamma-ray analysis system. 10 refs., 1 fig., 2 tabs.
Date: September 7, 1989
Creator: Ruhter, W. D. & Buckley, W. M.
Object Type: Report
System: The UNT Digital Library
Hyper filter-fluorescer spectrometer for x rays above 120 keV (open access)

Hyper filter-fluorescer spectrometer for x rays above 120 keV

An apparatus utilizing filter-fluorescer combinations is provided to measure short bursts of high fluence x-rays above 120 keV energy, where there are no practical absorption edges available for conventional filter-fluorescer techniques. The absorption edge of the prefilter is chosen to be less than that of the fluorescer, i.e., E/sub PRF/ < E/sub F/, contrary to the prior art technique E/sub PRF/ > E/sub F/. In this way, the response function is virtually zero between E/sub PRF/ and E/sub F/ and well defined and enhanced in an energy band of less than 1000 keV above the 120 keV energy.
Date: July 7, 1981
Creator: Wang, C. L.
Object Type: Patent
System: The UNT Digital Library
Design studies of a laser fusion power plant (open access)

Design studies of a laser fusion power plant

The conceptual design of a laser fusion power plant has been undertaken to exploit recent developments in target design. Advanced high-gain targets which have been developed make it possible to significantly relax the laser and optical system requirements. The power plant design features a reactor concept which utilizes a thick falling region of liquid lithium to protect the first-wall from the neutrons, x-rays, and charged particles that are produced in the thermonuclear microexplosion. The lithium waterfall has also been designed to be thick enough to significantly reduce the effects of 14 MeV neutrons and cyclical stresses on the blanket structure; thereby allowing us to consider smaller blanket structures which could last the lifetime of the plant. Fusion targets producing 700 MJ of thermonuclear energy are ignited by a 2 percent efficient, 1 MJ laser system at the rate of 1.4 Hz. Schemes for protecting the final focusing optics are described which are both compatible with this reactor system, and show promise of surviving a full year in order to minimize costly downtime.
Date: October 7, 1977
Creator: Maniscalco, J. A.; Meier, W. R. & Monsler, M. J.
Object Type: Article
System: The UNT Digital Library
Search for narrow states produced in the reaction. pi. /sup -/p. --&gt;. n +. gamma. &#x27;s at 13 GeV/c (open access)

Search for narrow states produced in the reaction. pi. /sup -/p. --&gt;. n +. gamma. &#x27;s at 13 GeV/c

A double arm lead-glass lead-scintillator calorimeter system was used to search for narrow states, such as the eta/sub c/, produced in the exclusive reactions ..pi../sup -/p ..--&gt;.. ..gamma gamma..n, ..pi../sup -/p ..--&gt;.. ..pi../sup 0/..gamma..n, and ..pi../sup -/p ..--&gt;.. ..pi../sup 0/..pi../sup 0/n at 13 GeV/c. A 90% c.l. upper limit sigma.BR &lt; 260 pb was found for ..gamma gamma.. states with masses from 2.6 to 3.1 GeV/c/sup 2/. Corresponding limits on narrow ..pi../sup 0/..gamma.. and ..pi../sup 0/..pi../sup 0/ states are also given.
Date: July 7, 1980
Creator: Chiang, I. H.; Johnson, R. A. & Kwan, B.
Object Type: Article
System: The UNT Digital Library
Geotomography applied at the Stripa Mine in Sweden (open access)

Geotomography applied at the Stripa Mine in Sweden

LLNL made ultrahigh-frequency (450-MHz) electromagnetic borehole-to-borehole transmissions in the Stripa Mine near Guldsmedshyttan, Sweden, in April 1979. Transmission loss measurements were made between four sets of 76-mm boreholes 30 m long, located at the end of a drift. Distances between the boreholes varied from 2 to 22 m. More than 25,000 data points were taken. A geotomograph was constructed to show the variation of attenuation between boreholes. The observed spatial variation of electromagnetic attenuation may be related to the expected stress relief created by the mine. Transmission loss measurements were also made between two converging boreholes drilled from the surface to points near the mine. Data taken at 21 MHz show a nearly uniform attenuation within this sampled region. These experiments demonstrate that geotomographic data collection/interpretation provides high-resolution images of the underground environment and can provide useful input to those charged with providing the detailed site characterizations needed for both short- and long-term monitoring of underground nuclear waste repositories.
Date: April 7, 1980
Creator: Okada, J.T.; Laine, E.F.; Lytle, R.J. & Daily,W.D.
Object Type: Report
System: The UNT Digital Library
PWR Blowdown Heat Transfer Separate-Effects Program. Thermal-Hydraulic Test Facility experimental data report for test 103 (open access)

PWR Blowdown Heat Transfer Separate-Effects Program. Thermal-Hydraulic Test Facility experimental data report for test 103

Reduced instrument responses are presented for Thermal-Hydraulic Test Facility (THTF) test 103, which is part of the ORNL Pressurized-Water Reactor (PWR) Blowdown Heat Transfer Separate-Effects Program. The objective of the program is to investigate the thermal-hydraulic phenomenon governing the energy transfer and transport processes that occur during a loss-of-coolant accident in a PWR system.
Date: March 7, 1978
Creator: Clemons, V. D.; White, M. D.; Moore, P. A. & Hedrick, R. A.
Object Type: Report
System: The UNT Digital Library
MTX (Microwave Tokamak Experiment) facility and machine grounding plan (open access)

MTX (Microwave Tokamak Experiment) facility and machine grounding plan

A key issue in the design of fusion research experiments and their related facilities is the control of ground currents. Because of the large magnetic field, high voltages and high currents present in most of these installations, it is essential to avoid ground loops, and to control ground currents during both normal operations and fault conditions. This paper describes the grounding policy that was developed for MTX. The vault area was divided into zones, and each of the four walls was treated as a separate grounding area. Cable runs and magnet buss bars were run into the machine radially. The paper also describes the steps taken to isolate diagnostic signals and power for pumps and instruments. The paper outlines some of the field calculations used to predict problem areas, and to reveal voltage isolation levels that were required. The paper includes the active ground fault detection system used to insure the integrity of the ground system. 2 refs., 5 figs.
Date: October 7, 1987
Creator: Bell, H.H.; Rice, B.W.; Petersen, D.E. & Herrera, C.H.
Object Type: Article
System: The UNT Digital Library
Atomic and molecular science with synchrotron radiation (open access)

Atomic and molecular science with synchrotron radiation

This paper discusses the following topics: electron correlation in atoms; atomic innershell excitation and decay mechanisms; timing experiments; x-ray scattering; properties of ionized species; electronic properties of actinide atoms; total photon-interaction cross sections; and molecular physics. 66 refs. (LSP)
Date: November 7, 1989
Creator: unknown
Object Type: Report
System: The UNT Digital Library
A miniature inexpensive, oxygen sensing element (open access)

A miniature inexpensive, oxygen sensing element

An exhaustive study was conducted to determine the feasibility of Nernst-type oxygen sensors based on ceramics containing Bi{sub 2}O{sub 3}. The basic sensor design consisted of a ceramic sensing module sealed into a metal tube. The module accommodated an internal heater and thermocouple. Thermal-expansion-matched metals, adhesives, and seals were researched and developed, consistent with sequential firings during sensor assembly. Significant effort was devoted to heater design/testing and to materials' compatibility with Pt electrodes. A systematic approach was taken to develop all sensor components which led to several design modifications. Prototype sensors were constructed and exhaustively tested. It is concluded that development of Nerst-type oxygen sensors based on Bi{sub 2}O{sub 3} will require much further effort and application of specialized technologies. However, during the course of this 3-year program much progress was reported in the literature on amperometric-type oxygen sensors, and a minor effort was devoted here to this type of sensor based on Bi{sub 2}O{sub 3}. These studies were made on Bi{sub 2}O{sub 3}-based ceramic samples in a multilayer-capacitor-type geometry and amperometric-type oxygen sensing was demonstrated at very low temperatures ({approximately} 160{degree}C). A central advantage here is that these types of sensors can be mass-produced very inexpensively ({approximately} 20--50 cents …
Date: October 7, 1991
Creator: Arenz, R. W.
Object Type: Report
System: The UNT Digital Library
MFTF-B quasi-optical ECRH transmission system (open access)

MFTF-B quasi-optical ECRH transmission system

The microwave transmission system for ERCH on MFTF-B will utilize quasi-optical transmission techniques. The system consists of ten gyrotron oscillators: two gyrotrons at 28 GHz, two at 35 GHz, and six at 56 GHz. The 28 and 35 GHz gyrotrons both heat the electrons in the end plug (potential peak) while the 56 GHz sources heat the minimum-B anchor region (potential minimum). Microwaves are launched into a pair of cylindrical mirrors that form a pseudo-cavity which directs the microwaves through the plasma numerous times before they are lost out of the cavity. The cavity allows the microwave beam to reach the resonance zone over a wide range of plasma densities and temperatures. The fundamental electron cyclotron resonance moves to higher axial positions as a result of beta-depression of the magnetic field, doppler shifting of the resonance, and relativistic mass corrections for the electrons. With this system the microwave beam will reach the resonance surface at the correct angle of incidence for any density or temperature without active aiming of the antennas. The cavity also allows the beam to make multiple passes through the plasma to increase the heating efficiency at low temperatures and densities when the single pass absorption is …
Date: November 7, 1983
Creator: Yugo, J. J.; Shearer, J. W. & Ziolkowski, R. W.
Object Type: Article
System: The UNT Digital Library
Acceleration using total internal reflection (open access)

Acceleration using total internal reflection

This report considers the use of a dielectric slab undergoing total internal reflection as an accelerating structure for charged particle beams. We examine the functional dependence of the electromagnetic fields above the surface of the dielectric for polarized incident waves. We present an experimental arrangement for testing the performance of the method, using apparatus under construction for the Grating Acceleration experiment at Brookhaven National Laboratory. 13 refs., 4 figs., 2 tabs.
Date: June 7, 1991
Creator: Fernow, R.C.
Object Type: Report
System: The UNT Digital Library
Superconducting (radiation hardened) magnets for mirror fusion devices (open access)

Superconducting (radiation hardened) magnets for mirror fusion devices

Superconducting magnets for mirror fusion have evolved considerably since the Baseball II magnet in 1970. Recently, the Mirror Fusion Test Facility (MFTF-B) yin-yang has been tested to a full field of 7.7 T with radial dimensions representative of a full scale reactor. Now the emphasis has turned to the manufacture of very high field solenoids (choke coils) that are placed between the tandem mirror central cell and the yin-yang anchor-plug set. For MFTF-B the choke coil field reaches 12 T, while in future devices like the MFTF-Upgrade, Fusion Power Demonstration and Mirror Advanced Reactor Study (MARS) reactor the fields are doubled. Besides developing high fields, the magnets must be radiation hardened. Otherwise, thick neutron shields increase the magnet size to an unacceptable weight and cost. Neutron fluences in superconducting magnets must be increased by an order of magnitude or more. Insulators must withstand 10/sup 10/ to 10/sup 11/ rads, while magnet stability must be retained after the copper has been exposed to fluence above 10/sup 19/ neutrons/cm/sup 2/.
Date: December 7, 1983
Creator: Henning, C. D.; Dalder, E. N. C.; Miller, J. R. & Perkins, J. R.
Object Type: Article
System: The UNT Digital Library
Estimating and coping with public response to radioactive waste repository siting (open access)

Estimating and coping with public response to radioactive waste repository siting

The siting and construction of a radioactive waste disposal operation is likely to be controversial in the communities being considered, and at the state and national levels as well. Public response can be conceptualized at two levels: individual, and group or organizational. At the individual level, public response is the behavior of people motivated by their attitudes, knowledge, and perceptions of radioactive waste and its hazards and risks. On the group or organizational level, public response is the organized activity of individuals. Organizations provide the ability to pool resources and talents, set up a division of labor, hire experts, develop a skilled leadership, take legal action, and so on. A broad range of organizations is possible: ad hoc, existing community groups with an added purpose, nationally-recognized organizations, or government offices and agencies. Two cases of response to radioactive waste disposal sites illustrate these sources and kinds of response and lead to indicators to estimate the nature and level of response. Finally, drawing from the theoretical discussion of the sources and levels of public response, on the estimation techniques, and on the examples, specific coping strategies are developed. These strategies take different forms, based on the nature and level of response …
Date: February 7, 1984
Creator: Payne, B.A.
Object Type: Article
System: The UNT Digital Library
Evaluation of macroreticular anion exchange resin - RTA-893-R (open access)

Evaluation of macroreticular anion exchange resin - RTA-893-R

The macroreticular anion exchange resin, Amberlite IRA-900-OH, and an experimental resin from Ionac Chemical Company were irradiated by a /sup 60/Co source to doses of 5 x 10/sup 7/ rad and 10/sup 8/ rad. These doses approximate or exceed the dose encountered by the deionizer resins in 100-Area service. The loss in exchange capacity and the volume changes of Amberlite IRA-900 on irradiation were similar to those found previously for Amberlite IRA-400. The Ionac experimental resin, which had a considerably lower initial exchange capacity, likewise was not stable to radiation. It is concluded that Amberlite IRA-900 offers no advantage over Amberlite IRA-400 for 100-Area purification service. Since there is little justification for further evaluation of macroreticular resin for 100-Area use, the present work completes RTA-893-R.
Date: June 7, 1965
Creator: Baumann, E. W.
Object Type: Report
System: The UNT Digital Library
Spatial averaging algorithms for ultrasonic inspection of austenitic stainless steel welds (open access)

Spatial averaging algorithms for ultrasonic inspection of austenitic stainless steel welds

Interpretation of ultrasonic inspection data from stainless steel welds is difficult because the signal-to-noise ratio is very low. The three main reasons for this are the granular structure of the weld, the high attenuation of stainless steel, and electronic noise. Averaging in time at the same position in space reduces electronic noise, but does not reduce ultrasonic noise from grain boundary scattering. Averaging wave-forms from different spatial positions helps reduce grain noise, but desired signals can destructively interfere if they shift in time. If the defect geometry is known, the ultrasonic waveforms can be shifted before averaging, ensuring signal reinforcement. The simplest geometry results in a linear time shift. An averaging algorithm has been developed which finds the optimum shift. This algorithm computes the averaged, or composite waveform as a function of the time shift. The optimum occurs when signals from a reflector become aligned in time, producing a large amplitude composite waveform. This algorithm works very well, but requires significant computer time and storage. This paper discusses this linear shift averaging algorithm, and considers an implementation using frequency domain techniques. Also, data from several weld defects are presented and analyzed.
Date: April 7, 1980
Creator: Horn, J. E.; Cooper, C.S. & Michaels, T.E.
Object Type: Article
System: The UNT Digital Library