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Nuclear waste management issues: a multidisciplinary evaluation framework.

Description: Initially, this paper characterizes the nuclear waste problem that requires analysis to establish the rationale for an interdisciplinary approach to resolve it. The problem characterization also explains why the specific concern with contaminated groundwater and intrusion through drilling has been selected for the focus of the panel meeting. The Nominal Group Technique (NGT), the group process format chosen for the experts' deliberations, is explained in some detail and its value in facilitatin… more
Date: February 1, 1980
Creator: Hoffman, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Research on the HYLIFE Liquid-First-Wall Concept for Future Laser-Fusion Reactors

Description: The experiments were designed to simulate the time period between microexplosions. Extrapolating the results of these small-scale experiments to the large-scale lithium jets, we have tentatively concluded that the lithium jets can be re-established after the microexplosion, and with careful design the jets should not breakup due to instabilities during the relatively quiescent period between microexplosions.
Date: October 1, 1981
Creator: Hoffman, M. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Research on the HYLIFE Liquid-First-Wall Concept for Future Laser-Fusion Reactors. Final Report No. 4, September 1977-March 1979

Description: It has been proposed to protect the structural walls of a future laser fusion reactor with a curtain or wall of liquid lithium jets. As part of the investigation of this concept, experiments have been performed on planar sheet water jets issuing vertically downward from slit nozzles. The nozzles were subjected to forced harmonic excitation to simulate the vibrational environment of the laser fusion reactor, and experiments were run at both 1 atm and 0.2 atm pressure. Linear temporal stability t… more
Date: March 1, 1979
Creator: Hoffman, M. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Boiling liquid cauldron status report

Description: The progress made over the past year in assessing the feasibility of the high-temperature, boiling cauldron blanket concept for the tanden mirror reactor is reviewed. The status of the proposed experiments and recently revised estimates of the vapor void fraction in the boiling pool are discussed.
Date: December 28, 1980
Creator: Hoffman, M. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Research on the HYLIFE Liquid-First-Wall Concept for Future Laser-Fusion Reactors. Final Report No. 5

Description: It has been proposed to protect the structural walls of a future laser fusion reactor with a curtain or fluid-wall of liquid lithium jets. As part of the investigation of this concept, experiments have been performed on planar sheet water jets issuing vertically downward from slit nozzles. The nozzles were subjected to transverse forced harmonic excitation to simulate the vibrational environment of the laser fusion reactor, and experiments were run at both 1 atm and at lower ambient pressures. … more
Date: September 1, 1980
Creator: Hoffman, M. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Research on the annular lithium jet concept for future laser-fusion reactors. Final report No. 3, Sept 1977--Dec 1978

Description: Experiments have been performed to determine the length for convergence or closure of a vertical, hollow annular water jet due to the action of surface tension forces. The data agree well with theoretical predictions up to a velocity of about 3 m/s. At higher velocities, the convergence lengths are less than predicted and this is attributed to the jet acting as an ejector pump and thereby reducing the air pressure inside the annulus to slightly sub-atmospheric values. The stability of such a je… more
Date: December 1, 1978
Creator: Hoffman, M. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Research on the HYLIFE Liquid-First-Wall Concept for Future Laser-Fusion Reactors: Liquid Jet Impact Experiments. Final Report No. 8

Description: The goal of this initial scoping study was to evaluate the transient and steady state drag of a single bar and of some selected arrays of bars and to determine the momentum removed from impacting liquid slugs. In order to achieve this aim, use has been made of both the published literature and experimental data obtained from a small-scale experimental apparatus. The implications of two possible scaling laws for use in designing the small-scale experiment are discussed. The use of near-universal… more
Date: August 1, 1982
Creator: Hoffman, M. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Research on the HYLIFE Liquid-First-Wall Concept for Future Laser-Fusion Reactors. Final Report No. 6

Description: Experiments were performed on planar sheet jets of water flowing vertically downward. The nozzles were vibrated transversely to excite the sinuous mode of instability, and the sheet jets were photographed from the edge view to obtain data on the wave growth parameters. The data are compared to a second-order nonlinear theory. Qualitative agreement is obtained with regard to the stabilizing nature of the second-order terms, and reasonably quantitative agreement is obtained on the fall distance f… more
Date: December 1, 1980
Creator: Hoffman, M. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Photochemical Determinants of the Efficiency of Photogalvanic Conversion of Solar Energy

Description: A photogalvanic cell is a battery in which the cell solution absorbs light directly to generate species which, upon back reaction through an external circuit with the aid of suitable electrodes, produces electric power; photoactivation of the electrodes is not involved. The charge-carrying species have storage capacity if they are long-lived and can be prevented from engaging in degradative back reactions in bulk solution. The efficiency of a photogalvanic cell for the conversion of photon ener… more
Date: January 1, 1979
Creator: Hoffman, M. Z. & Lichtin, N. N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Thermal hydraulic study of the ESPRESSO blanket for a Tandem Mirror Reactor

Description: This paper deals primarily with the thermal-hydraulic design and some critical thermomechanical aspects of the proposed ESPRESSO blanket for the Tandem Mirror Fusion Reactor. This conceptual design was based on the same physics as used in the MARS study.
Date: February 1, 1986
Creator: Raffray, A. R. & Hoffman, M. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Water-cooled U-tube grids for continuously operated neutral-beam injectors

Description: A design for water-cooled extractor grids for long-pulse and continuously operated ion sources for neutral-beam injectors is described. The most serious design problem encountered is that of minimizing the thermal deformation (bowing) of these slender grid rails, which have typical overall spans of 150 mm and diameters on the order of 1 mm. A unique U-tube design is proposed that offers the possibility of keeping the thermal bowing down to about 0.05 mm (about 2.0 mils). However, the design req… more
Date: November 5, 1979
Creator: Hoffman, M. A. & Duffy, T. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Optimizing the heat pipe for operation in a magnetic field when liquid-metal working fluids are used

Description: A novel method for reducing the magnetohydrodynamic (MHD) pressure drops in the liquid metal flow in a heat pipe wick is described. By flattening the heat pipe, the eddy current return path in the metallic heat pipe wall is inreased significantly, thereby increasing the effective wall resistance. This, in turn, reduces the magnitude of the MHD pressure drop. The same principle can also be applied to flows of liquid metal coolants in a magnetic field.
Date: May 18, 1981
Creator: Werner, R. W. & Hoffman, M. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Gas-cooled, Li/sub 2/O moderator/breeder canister blanket for fusion-synfuels

Description: A new integrated power and breeding blanket is described. The blanket incorporates features that make it suitable for synthetic fuel production. It is matched to the thermal and electrical requirements of the General atomic water-splitting process for producing hydrogen. The fusion reaction is the Tandem Mirror Reactor (TMR) using Mirror Advanced Reactor Study (MARS) physics. The canister blanket is a high temperature, pressure balanced, cross-flow heat exchanger contained within a low activity… more
Date: March 24, 1983
Creator: Werner, R. W. & Hoffman, M. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Two-phase-flow cooling concept for fusion reactor blankets

Description: The new two-phase heat transfer medium proposed is a mixture of potassium droplets and helium which permits blanket operation at hih temperature and low pressure, while maintaining acceptable pumping power requirements, coolant ducting size, and blanket structure fractions. A two-phase flow model is described. The helium pumping power and the primary heat transfer loop are discussed. (MOW)
Date: January 14, 1977
Creator: Bender, D. J. & Hoffman, M. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Temporal observations of the lambda5303 emission line profile during the 74 minute totality from the Concorde SST at the 30 June 1973 total solar eclipse: preliminary intensity variations above an active region

Description: From international astronomical union symposium on coronal disturbances; Surfers Paradise, Australia (3 Sep 1973). Apparatus was designed for installation on the Concorde SST to provide high resolution emission line profiles at the June 30, 1973 total solar eclipse. A prime objective was to obtain profiles that could be used to detect the coronal response to the 5 min periodicities observed in the solar photosphere. Stability of the sky scattered light, drastic reduction of seeing effects enhan… more
Date: August 28, 1973
Creator: Liebenberg, D.H. & Hoffman, M.M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Research on the wetted first wall concept for future laser fusion reactors. Final report No. 1, October 1, 1974--January 31, 1976

Description: Research is in progress to determine the feasibility of the wetted first wall concept for a future laser fusion reactor. The basic idea involves the use of a thin coating of lithium on the inner wall of the laser fusion containment vessel to protect it from the micro-explosion blast debris. This report contains a review of the available information on contact angles and wettability of alkali metals on various metal substrates as well as a review of literature on thin falling liquid films. A pro… more
Date: January 1, 1976
Creator: Hoffman, M. A. & Munir, Z. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Study of Intermediates From Transition Metal Excited-State Electron- Transfer Reactions

Description: Progress on 6 projects is reported: excited state absorption spectrum of Ru(bpy)[sub 3][sup 2+], solvent cage model for electron transfer quenching, reductive quenching of [sup *]Cr(III) complexes, solution medium effects in oxidative quenching of [sup *]Ru(II) complexes, photosensitized oxidation of phenol in aqueous solution, and quenching of Ru(II) complexes by oxygen.
Date: March 31, 1993
Creator: Hoffman, M. Z.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Study of Intermediates From Transition Metal Excited-State Electron- Transfer Reactions. Progress Report, January 1, 1992--March 31, 1993

Description: Progress on 6 projects is reported: excited state absorption spectrum of Ru(bpy){sub 3}{sup 2+}, solvent cage model for electron transfer quenching, reductive quenching of {sup *}Cr(III) complexes, solution medium effects in oxidative quenching of {sup *}Ru(II) complexes, photosensitized oxidation of phenol in aqueous solution, and quenching of Ru(II) complexes by oxygen.
Date: March 31, 1993
Creator: Hoffman, M. Z.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Study of Intermediates From Transition Metal Excited-State Electron-Transfer Reactions

Description: During this period, conventional and fast-kinetics techniques of photochemistry, photophysics, radiation chemistry, and electrochemistry were used for the characterization of the intermediates that are involved in transition metal excited-state electron-transfer reactions. The intermediates of interest were the excited states of Ru(II) and Cr(III) photosensitizers, their reduced forms, and the species formed in the reactions of redox quenchers and electron-transfer agents. Of particular concern… more
Date: December 31, 1991
Creator: Hoffman, M. Z.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Study of Intermediates From Transition Metal Excited-State Electron-Transfer Reactions

Description: Conventional and fast-kinetics techniques of photochemistry, photophysics, radiation chemistry, and electrochemistry were used to study the intermediates involved in transition metal excited-state electron-transfer reactions. These intermediates were excited state of Ru(II) and Cr(III) photosensitizers, their reduced forms, and species formed in reactions of redox quenchers and electron-transfer agents. Of particular concern was the back electron-transfer reaction between the geminate pair form… more
Date: July 31, 1992
Creator: Hoffman, M. Z.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Study of Intermediates From Transition Metal Excited-State Electron-Transfer Reactions. Progress Report, August 1, 1989--December 31, 1991

Description: During this period, conventional and fast-kinetics techniques of photochemistry, photophysics, radiation chemistry, and electrochemistry were used for the characterization of the intermediates that are involved in transition metal excited-state electron-transfer reactions. The intermediates of interest were the excited states of Ru(II) and Cr(III) photosensitizers, their reduced forms, and the species formed in the reactions of redox quenchers and electron-transfer agents. Of particular concern… more
Date: December 31, 1991
Creator: Hoffman, M. Z.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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