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The Choctaws Indians in the Middle of the Nineteenth Century (open access)

The Choctaws Indians in the Middle of the Nineteenth Century

Article is a lecture given by Reverend John Edwards to the student body at the University of California regarding his observations and experiences working as a missionary within Indian Territory.
Date: Autumn 1932
Creator: Edwards, John & Swanton, John R.
System: The Gateway to Oklahoma History
Edward W. Bushyhead and John Rollin Ridge: Cherokee Editors in California (open access)

Edward W. Bushyhead and John Rollin Ridge: Cherokee Editors in California

Article chronicles how Edward W. Bushyhead and John Rollin Ridge established newspapers within California during their search for gold.
Date: Autumn 1936
Creator: Foreman, Carolyn Thomas, 1872-1967
System: The Gateway to Oklahoma History
[The Dallas Morning News, 'Museum director resigns'] (open access)

[The Dallas Morning News, 'Museum director resigns']

An article written by Janet Kutner for The Dallas Morning News that announces the resignation of E. A. Carmean Jr. as director of the Modern Art Museum of Fort Worth. The piece covers the work he did while at the museum.
Date: 199X
Creator: Kutner, Janet
System: The UNT Digital Library
Experimental evaluation of a fixed collector employing vee-trough concentrator and vacuum tube receivers (open access)

Experimental evaluation of a fixed collector employing vee-trough concentrator and vacuum tube receivers

A test bed for experimental evaluation of a fixed solar collector which combines an evacuated glass tube solar receiver with a flat plate/black chrome plated copper absorber and an asymmetric veetrough concentrator was designed and constructed. Earlier predictions of thermal performance were compared with test data acquired for a bare vacuum tube receiver; and receiver tubes with Alzak aluminum, aluminized FEP Teflon film laminated sheet metal and second surface ordinary mirror reflectors. Test results and system economics as well as objectives of an ongoing program to obtain long-term performance data are discussed.
Date: January 1, 1977
Creator: Selcuk, M. K.
System: The UNT Digital Library
Generation of a strong core-centering force in a submillimeter compound droplet system (open access)

Generation of a strong core-centering force in a submillimeter compound droplet system

By amplitude-modulating the driving voltage of an acoustic levitating apparatus, a strong core-centering force can be generated in a submillimeter compound droplet system suspended by the radiation pressure in a gaseous medium. Depending on the acoustic characteristics of the droplet system, it has been found that the technique can be utilized advantageously in the multiple-layer coating of an inertial-confinement-fusion pellet.
Date: January 1, 1981
Creator: Lee, M. C.; Feng, I.; Elleman, D. D.; Wang, T. G. & Young, A. T.
System: The UNT Digital Library
Plasma properties of driver gas following interplanetary shocks observed by ISEE-3 (open access)

Plasma properties of driver gas following interplanetary shocks observed by ISEE-3

Plasma fluid parameters calculated from solar wind and magnetic field data obtained on ISEE 3 were studied to determine the characteristic properties of driver gas following interplanetary shocks. Of 54 shocks observed from August 1978 to February 1980, 9 contained a well defined driver gas that was clearly identifiable by a discontinuous decrease in the average proton temperature across a tangential discontinuity. While helium enhancements were present in all of 9 of these events, only about half of them contained simultaneous changes in the two quantities. Often the He/H ratio changed over a period of minutes. Simultaneous with the drop in proton temperature the helium and electron temperature decreased abruptly. In some cases the proton temperature depression was accompanied by a moderate increase in magnetic field magnitude with an unusually low variance and by an increase in the ratio of parallel to perpendicular temperature. The drive gas usually displayed a bi-directional flow of suprathermal solar wind electrons at higher energies (>137 eV).
Date: January 1, 1982
Creator: Zwickl, R. D.; Asbridge, J. R.; Bame, S. J.; Feldman, W. C.; Gosling, J. T. & Smith, E. J.
System: The UNT Digital Library
Refractory materials for high-temperature thermoelectric energy conversion (open access)

Refractory materials for high-temperature thermoelectric energy conversion

Theoretical work of two decades ago adequately explained the transport behavior and effectively guided the development of thermoelectric materials of high conversion efficiencies of conventional semiconductors (e.g., SiGe alloys). The more significant contributions involved the estimation of optimum doping concentrations, the reduction of thermal conductivity by solid solution doping and the development of a variety of materials with ZT approx. 1 in the temperature range 300 K to 1200 K. It was also shown that ZT approx. 1 is not a theoretical limitation although, experimentally, values in excess of one were not achieved. Work has continued with emphasis on higher temperature energy conversion. A number of promising materials have been discovered in which it appears that ZT > 1 is realizable. These materials can be divided into two classes: (i) the rare-earth chalcogenides, which behave as itinerant highly-degenerate n-type semiconductors at room-temperature, and (ii) the boron-rich borides, which exhibit p-type small-polaronic hopping conductivity.
Date: January 1, 1983
Creator: Wood, C. & Emin, D.
System: The UNT Digital Library
Semiconductor processing with excimer lasers (open access)

Semiconductor processing with excimer lasers

The advantages of pulsed excimer lasers for semiconductor processing are reviewed. Extensive comparisons of the quality of annealing of ion-implanted Si obtained with XeCl and ruby lasers have been made. The results indicate that irrespective of the large differences in the optical properties of Si at uv and visible wavelengths, the efficiency of usage of the incident energy for annealing is comparable for the two lasers. However, because of the excellent optical beam quality, the XeCl laser can provide superior control of the surface melting and the resulting junction depth. Furthermore, the concentrations of electrically active point defects in the XeCl laser annealed region are 2 to 3 orders of magnitude lower than that obtained from ruby or Nd:YAG lasers. All these results seem to suggest that XeCl lasers should be suitable for fabricating not only solar cells but also the more advanced device structures required for VLSI or VHSIC applications.
Date: January 1, 1983
Creator: Young, R.T.; Narayan, J.; Christie, W.H.; van der Leeden, G.A.; Rothe, D.E. & Cheng, L.J.
System: The UNT Digital Library
SP-100, a project manager`s view. Technical information report (open access)

SP-100, a project manager`s view. Technical information report

Born to meet the special needs of America`s space effort, the SP-100 Program testifies to the cooperation among government agencies. The Department of Energy (DOE), the National Aeronautics and Space Administration (NASA), and the Defense Advanced Research Projects Agency (DARPA) are working together to produce a 100-kW power system for use in outer space. At this point in the effort, it is appropriate to review: The approach to meet program goals; the status of activities of the Project Office, managed by the Jet Propulsion Laboratory (JPL); and, because this is a meeting on materials, answers beings developed by the Project Office to vital questions on refractory alloy technology.
Date: December 1, 1983
Creator: Truscello, V. C.
System: The UNT Digital Library
Dual arm master controller concept (open access)

Dual arm master controller concept

The Advanced Servomanipulator (ASM) slave was designed with an anthropomorphic stance, gear/torque tube power drives, and modular construction. These features resulted in increased inertia, friction, and backlash relative to tape-driven manipulators. Studies were performed which addressed the human factors design and performance trade-offs associated with the corresponding master controller best suited for the ASM. The results of these studies, as well as the conceptual design of the dual arm master controller, are presented. 6 references, 3 figures.
Date: January 1, 1984
Creator: Kuban, D.P. & Perkins, G.S.
System: The UNT Digital Library
External flow radiators for reduced space powerplant temperatures. Technical information report (open access)

External flow radiators for reduced space powerplant temperatures. Technical information report

Nuclear space powerplants can operate at temperatures below 900 K and use stainless steel construction without a weight penalty if new radiator concepts can achieve radiator weights of 1-3 kg/m{sup 2}. Conventional tube-and-fin radiators weight about 10 kg/m{sup 2} because of heavy tube walls to prevent meteroid puncture. Radiator designs that do not require meteroid protection are possible; they operate with fluids of low vapor pressure that can be exposed directly to space in external-flow radiators. An example is the {open_quotes}rotating disk radiator{close_quotes} in which centrifugal force drives a liquid film radially outward across a thin rotating metal disk; meteroid punctures cause no loss of fluid other than from evaporation, which can be small. An even lighter concept is the liquid drop radiator in which heat is radiated directly from moving liquid drops. Such radiator concepts look practical, and they may be much easier to develop than the high-temperature, refractory-metal power systems necessitated by conventional radiators.
Date: January 1, 1984
Creator: Elliott, D. G.
System: The UNT Digital Library
Space nuclear power system and the design of the nuclear electric propulsion OTV (open access)

Space nuclear power system and the design of the nuclear electric propulsion OTV

Payload increases of three to five times that of the Shuttle/Centaur can be achieved using nuclear electric propulsion. Various nuclear power plant options being pursued by the SP-100 Program are described. These concepts can grow from 100 kW/sub e/ to 1MW/sub e/ output. Spacecraft design aspects are addressed, including thermal interactions, plume interactions, and radiation fluences. A baseline configuration is described accounting for these issues. Safety aspects of starting the OTV transfer from an altitude of 300 km indicate no significant additional risk to the biosphere.
Date: January 1, 1984
Creator: Buden, D. & Garrison, P.W.
System: The UNT Digital Library
[Clipping: 'Our Daring Young Women': WWII role models guide women pilots] (open access)

[Clipping: 'Our Daring Young Women': WWII role models guide women pilots]

Photocopy of an clipping on the legacy of Women Airforce Service Pilots, their contributions to World War II, and their eventual fight to gain veteran status.
Date: November 1984
Creator: Watson, Liz
System: The Portal to Texas History
Dual arm master controller development (open access)

Dual arm master controller development

The advanced servomanipulator (ASM) slave was designed with an anthropomorphic stance, gear/torque tube power drives, and modular construction. These features resulted in increased inertia, friction, and backlash relative to tape-driven manipulators. Studies were performed which addressed the human factors design and performance trade-offs associated with the corresponding master controller best suited for the ASM. The results of these studies, as well as the conceptual design of the dual arm master controller, are presented. This work was performed as part of the Consolidated Fuel Reprocessing Program at the Oak Ridge National Laboratory. 5 refs., 7 figs., 1 tab.
Date: January 1, 1985
Creator: Kuban, D. P. & Perkins, G. S.
System: The UNT Digital Library
Low Energy X-Ray Spectra Measured With a Mercuric Iodide Energy Dispersive Spectrometer in a Scanning Electron Microscope (open access)

Low Energy X-Ray Spectra Measured With a Mercuric Iodide Energy Dispersive Spectrometer in a Scanning Electron Microscope

A mercuric iodide energy dispersive x-ray spectrometer, with Peltier cooling provided for the detector and input field effect transistor, has been developed and tested in a scanning electron microscope. X-ray spectra were obtained with the 15 keV electron beam. An energy resolution of 225 eV (FWHM) for Mn-K/sub ..cap alpha../ at 5.9 keV and 195 eV (FWHM) for Mg-K line at 1.25 keV has been measured. Overall system noise level was 175 eV (FWHM). The detector system characterization with a carbon target demonstrated good energy sensitivity at low energies and lack of significant spectral artifacts at higher energies. 16 refs., 5 figs.
Date: January 1, 1985
Creator: Iwanczyk, J. S.; Dabrowski, A. J.; Huth, G. C.; Bradley, J. G.; Conley, J. M. & Albee, A. L.
System: The UNT Digital Library
Neutral sheet crossings in the distant magnetotail (open access)

Neutral sheet crossings in the distant magnetotail

We have analyzed the magnetic field data from ISEE-3 in the distant magnetotail for 18 crossings of the cross-tail current sheet (or so-called natural sheet) to determine the direction of the normal component B/sub z/. The crossings occurred near the middle of the aberrated magnetotail (0 < y < 30 R/sub e, -10 < z < 5) in GSM coordinates, at a distance of about 220 R/sub e/, January 28 to February 12, 1983; in each case the plasma flow velocity was tailward. In 2 cases we found B/sub z/ negative (southward), as would be required with a magnetic neutral line (reconnection line) earthward of the spacecraft. In 12 cases B/sub z/ was clearly northward (B/sub z/ > 0.4 nT), consistent with closed field lines connected to the earth. In 3 cases B/sub z/ was very close to zero; in several instances there was structure in B/sub y/, suggesting localized currents with x or z directions. One may have been a magnetopause crossing. The strong preponderance of northward B/sub z/ favors a model of the magnetotail which is dominated by boundary layer plasma, flowing tailward on closed magnetic field lines, which requires the existence of an electric field in the …
Date: January 1, 1985
Creator: Heikkila, W. J.; Slavin, J. A.; Smith, E. J.; Baker, D. N. & Zwickl, R. D.
System: The UNT Digital Library
PEGASUS: a multi-megawatt nuclear electric propulsion system (open access)

PEGASUS: a multi-megawatt nuclear electric propulsion system

With the Space Transportation System (STS), the advent of space station Columbus and the development of expertise at working in space that this will entail, the gateway is open to the final frontier. The exploration of this frontier is possible with state-of-the-art hydrogen/oxygen propulsion but would be greatly enhanced by the higher specific impulse of electric propulsion. This paper presents a concept that uses a multi-megawatt nuclear power plant to drive an electric propulsion system. The concept has been named PEGASUS, PowEr GenerAting System for Use in Space, and is intended as a ''work horse'' for general space transportation needs, both long- and short-haul missions. The recent efforts of the SP-100 program indicate that a power system capable of producing upwards of 1 megawatt of electric power should be available in the next decade. Additionally, efforts in other areas indicate that a power system with a constant power capability an order of magnitude greater could be available near the turn of the century. With the advances expected in megawatt-class space power systems, the high specific impulse propulsion systems must be reconsidered as potential propulsion systems. The power system is capable of meeting both the propulsion system and spacecraft power requirements.
Date: June 1, 1985
Creator: Coomes, Edmund P.; Cuta, Judith M.; Webb, Brent J. & King, David Q.
System: The UNT Digital Library
MHD waves detected by ice at distances > 28 x 10/sup 6/ km from Comet Halley: Cometary or solar wind origin (open access)

MHD waves detected by ice at distances > 28 x 10/sup 6/ km from Comet Halley: Cometary or solar wind origin

Spectral analyses of the high resolution magnetic field data are employed to determine if there is evidence of cometary heavy ion pickup when ICE was closest to Halley, approx.28 x 10/sup 6/ km. No evidence is found for the presence of heavy ion cyclotron waves. However, from this search, two new wave modes are discovered in the solar wind: electromagnetic ion cyclotron waves and drift mirror mode waves. Both modes have scales of 10 to 60 s (1 to 6 T/sub p/) in the spacecraft frame. The possibility of wave generation by cometary hydrogen pickup is explored. Theoretical arguments and further experimental evidence indicates that cometary origin is improbable. The most likely source is plasma instabilities associated with solar wind stream-stream interactions. VLF electrostatic emissions are found to occur in field minima or at gradients of the drift mirror structures. Possible generation mechanisms of drift mirror mode waves, cyclotron waves and electrostatic waves are discussed.
Date: January 1, 1986
Creator: Tsurutani, B. T.; Brinca, A. L.; Smith, E. J.; Thorne, R. M.; Scarf, F. L.; Gosling, J. T. et al.
System: The UNT Digital Library
The P/Giacobini-Zinner Magnetotail (open access)

The P/Giacobini-Zinner Magnetotail

On September 11, 1985 the International Cometary Explorer passed behind Comet Giacobini-Zinner with a closest approach distance of 7800 km. In agreement with Alfven's interplanetary magnetic field line draping model of cometary type I tails, a well defined 1 x 10/sup 4/ km diameter magnetotail was observed downstream of the inner coma. This study uses the ICE magnetic field, plasma electron, plasma wave, and energetic ion observations to investigate the structure and stability of the Giacobini-Zinner magnetic tail. Emphasis is placed on the identification of differences and similarities between cometary and planetary magnetotails. Finally, the ICE magnetotail observations are discussed in relation to the global solar wind interaction with P/Giacobini-Zinner. 33 refs., 8 figs.
Date: January 1, 1986
Creator: Slavin, J. A.; Smith, E. J.; Daly, P. W.; Flammer, K. R.; Gloeckler, G.; Goldberg, B. A. et al.
System: The UNT Digital Library
Steepened magnetosonic waves in the high. beta. plasma surrounding Comet Giacobini-Zinner (open access)

Steepened magnetosonic waves in the high. beta. plasma surrounding Comet Giacobini-Zinner

We extend the previous studies of intense hydromagnetic waves at Giacobini-Zinner to investigate the mode and direction of wave propagation. Simultaneous high-resolution measurements of electron density fluctuations demonstrate that the long period (approx.100 s) waves are propagating in the magnetosonic mode. Principal axis analyses of the long period waves and accompanying partial rotations show that the sum of the wave phase rotations is 360/sup 0/C, indicating that both are parts of the same wave oscillation. From the time sequence of the steepened waveforms observed by ICE, we demonstrate that the waves must propagate towards the sun with C/sub ph/ < V/sub sw/. All available observations are consistent with wave generation by the resonant ion ring or ion beam instability which predicts right-hand polarized waves propagating in the ion beam (solar) direction. The large amplitudes ..delta.. polarized B/absolute value of Bapprox.0(1) and small scale sizes (rotational discontinuities) of the cometary waves suggest that rapid pitch-angle scattering and energy transfer with energetic ions should occur. Since the waves are highly compressive, ..delta.. absolute value of B/absolute value of B = 0(0.5), one can also anticipate first-order Fermi acceleration. 15 refs., 6 figs.
Date: January 1, 1986
Creator: Tsurutani, B. T.; Smith, E. J.; Thorne, R. M.; Gosling, J. T. & Matsumoto, H.
System: The UNT Digital Library
The comet Giacobini-Zinner magnetotail: Axial stresses and inferred near-nucleus properties (open access)

The comet Giacobini-Zinner magnetotail: Axial stresses and inferred near-nucleus properties

Utilizing the electron and magnetic field data from the ICE tail traversal of Comet Giacobini-Zinner along with the MHD equations, we have developed a steady state, stress balance model of the cometary magnetotail. With it we infer many important but unmeasured ion properties within the G-Z magnetotail both at ICE and upstream at the average point along each streamline where cometary ions are picked-up. The derived tailward ion flow speed at ICE is quite constant at approx.-20 to -30 km/sec across the entire tail. The flow velocity, ion temperature, density, and ion source rates upstream from the lobes (current sheet) at the average pickup locations are approx.-75 km/sec (approx.-12), approx.4 x 10/sup 6/ K (approx.1 x 10/sup 5/), approx.20 /cm/sup 3/ (approx.400), and approx..15 /cm/sup 3//sec (approx.3.6). Gradients in the plasma properties between these two regions are quire strong. Implications of our inferred plasma properties for the near-nucleus region and for cometary magnetotail formation are examined. 9 refs., 1 fig.
Date: October 1, 1986
Creator: McComas, D. J.; Gosling, J. T.; Bame, S. J.; Slavin, J. A.; Smith, E. J. & Steinberg, J. L.
System: The UNT Digital Library
Interplanetary propulsion using inertial fusion (open access)

Interplanetary propulsion using inertial fusion

Inertial fusion can be used to power spacecraft within the solar system and beyond. Such spacecraft have the potential for short-duration manned-mission performance exceeding other technologies. We are conducting a study to assess the systems aspects of inertial fusion as applied to such missions, based on the conceptual engine design of Hyde (1983) we describe the required systems for an entirely new spacecraft design called VISTA that is based on the use of DT fuel. We give preliminary design details for the power conversion and power conditioning systems for manned missions to Mars of total duration of about 100 days. Specific mission performance results will be published elsewhere, after the study has been completed.
Date: January 1, 1987
Creator: Orth, C.D.; Hogan, W.J.; Hoffman, N.; Murray, K.; Klein, G. & Diaz, F.C.
System: The UNT Digital Library
Transport vehicle for manned Mars missions powered by inertial confinement fusion (open access)

Transport vehicle for manned Mars missions powered by inertial confinement fusion

Inertial confinement fusion (ICF) is an ideal engine power source for manned spacecraft to Mars because of its inherently high power-to-mass ratios and high specific impulses. We have produced a concept for a vehicle powered by ICF and utilizing a magnetic thrust chamber to avoid plasma thermalization with wall structures and the resultant degradation of specific impulse that are unavoidable with the use of mechanical thrust chambers. This vehicle is capable of 100-day manned Mars missions with a 100-metric-ton payload and a total vehicle launch mass near 6000 metric tons, based on advanced technology assumed to be available by A.D. 2020. Such short-duration missions minimize radiation exposures and physiological deterioration of astronauts.
Date: June 26, 1987
Creator: Orth, C.D.; Klein, G.; Sercel, J.; Hoffman, N.; Murray, K. & Chang-Diaz, F.
System: The UNT Digital Library