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Kinetics of an H$sub 2$--F$sub 2$ explosion as initiated by a pulse of fluorine atoms

Description: The elementary reactions occurring in an H/sub 2/-F/sub 2/ explosion are given with each vibrational level of H/sub 2/ and HF considered as a separate reacting species. Rate coefficients for all the elementary reactions are either estimated or calculated, and the major assumptions entering into the determination of each rate coefficient are given. The effect of non-Maxwell distributions in the translational energies of some of the species is estimated. For strong pulses of F atoms, the explosion is complete before any appreciable contribution to the rate is made by thermal dissociation of F/sub 2/ or H/sub 2/. (auth)
Date: February 1, 1974
Creator: Sullivan, J.H. & Feber, R.C.
Partner: UNT Libraries Government Documents Department

Thermochemical correlation of material transport in an alkali metal heat pipe

Description: The use of high-power heat pipes in space power systems requires a means of life prediction. The design lifetimes required make experimental determination of life impractical. Thermochemical modeling of heat pipe corrosive failure modes has been investigated as a means of making such prediction. Results have been applied to tests of molybdenum-lithium heat pipes operating from 1400 to 1500/sup 0/K. A free energy minimization routine coupled to a hydrodynamic model of the operating heat pipe has been used to give local equilibrium values of reaction products as a function of operating time. The predicted reactions for critical regions of the heat pipe were compared with limited results of post-test examinations. Corrosive damage to the heat pipe wick structure was correlated with high oxygen and nitrogen activity in the evaporator region of the heat pipe.
Date: January 1, 1985
Creator: Merrigan, M.A. & Feber, R.C.
Partner: UNT Libraries Government Documents Department

Corrosion in alkali metal/molybdenum heat pipes

Description: Molybdenum/sodium (Mo/Na) and molybdenum/lithium (Mo/Li) heat pipes have been operated for long periods of time in a study of their resistance to failure by alkali metal corrosion. Some Mo/Na heat pipes have operated over 20,600 h at 1400 K without failure, while at least one similar heat pipe failed in less than 14 hours at 1435 K. Detailed post-mortem analyses which have been performed on three failed Mo/Na heat pipes all indicated impurity controlled corrosion of their evaporators. Impurities observed to be transported included carbon, oxygen, and silicon. A Mo/Li heat pipe that failed after 25,216 h of operation at 1700 K was also examined in detail. This failure was due to nickel impurities being transported to the evaporator resulting in perforation of the container tube by the formation of a low melting Mo-Ni alloy. Theoretical thermochemical calculations were conducted for these systems with the objective of corroborating the corrosion mechanisms in both types of heat pipes. The results of these calculations are in general agreement with the observed corrosion a phenomena.
Date: January 1, 1984
Creator: Lundberg, L.B. & Feber, R.C. Jr.
Partner: UNT Libraries Government Documents Department

Thermochemical modeling of mass transport in high-temperature heat pipes

Description: A dynamic model of mass transport due to nonmetallic contaminants in refractory metal-alkali metal heat pipes has been developed. The model has been applied to heat pipes proposed for applications in space power systems using actual dimensions and powers. Results have been used to predict the operating lifetimes of the systems and to suggest mechanisms for mass transport observed in extended laboratory tests. Limitations of the model due to uncertainties in data for the effect of oxygen and nitrogen on the solubility of refractory metals in the alkali metals are discussed.
Date: January 1, 1987
Creator: Feber, R.C. & Merrigan, M.A.
Partner: UNT Libraries Government Documents Department

Geochemical considerations for Hot, Dry Rock Systems

Description: Circulating systems intended to model the P-T conditions found in the natural HDR (Hot Dry Rock) geothermal system at Los Alamos have been built. Experiments with these systems have determined the following parameters for the ''down hole'' reservoir: sample weight loss, circulating solution composition, textural changes in the rock, mineral loss from the rock and effects of chemical additives on rock erosion. The analyses of solutions generated from rock-water interactions in the experimental systems show the extremely dilute nature of the working fluid. These solutions are not brines. Silica scaling in the surface heat exchanger was found to account for the difference between loss of sample rate and analyzed silica in the solution. The weight loss data indicate that there was continuous transport of silica from the ''down hole'' rock to the heat exchanger. Experiments contrasting felsic and mafic rocks in the HDR concept indicate that a reservoir consisting of glass bearing basaltic rock would tend to produce greater scaling problems than systems emplaced in granite. Experimental results suggest that Na{sub 2}CO{sub 3} solutions may provide a means of increasing permeability and thereby increasing the effective heat transfer area of the reservoir. A brief description is given of a small test loop for simulating the flow of a geothermal solution through a heat exchanger. This loop, which is being built, will be used to study the coagulation and precipitation of silica under conditions similar to those expected in the field.
Date: January 1, 1976
Creator: Balagna, J.; Blatz, L.; Charles, R.; Feber, R.; Herrick, C.; Holley, C. et al.
Partner: UNT Libraries Government Documents Department


Description: The thermodynamic properties of refractory borides, carbides, nitrides, and oxides of some 31 elements are compiled. Several tables for elements and compounds not previously reported are presented, and the experimental spectroscopic studies of the vapor of boron oxide and hydroxide are discussed. (R.J.S.)
Date: December 15, 1962
Creator: Schick, H.L.; Anthrop, D.F.; Dreikorn, R.E.; Feber, R.C.; Hanst, P.L.; Panish, M.B. et al.
Partner: UNT Libraries Government Documents Department

Hydrogen recovery from extraterrestrial materials using microwave energy

Description: The feasibility of recovering hydrogen from extraterrestrial materials (lunar and Martian soils, asteroids) using microwave energy is presented. Reasons for harvesting and origins and locations of hydrogen are reviewed. Problems of hydrogen recovery are discussed in terms of hydrogen release characteristics and microwave coupling to insulating materials. From results of studies of hydrogen diffusivities (oxides, glasses) and tritium release (oxides) as well as studies of microwave coupling to ilmenite, alkali basalt and ceramic oxides it is concluded that using microwave energy in hydrogen recovery from extraterrestrial materials could be the basis for a workable process.
Date: January 1, 1984
Creator: Tucker, D.S.; Vaniman, D.T.; Anderson, J.L.; Clinard, F.W. Jr.; Feber, R.C. Jr.; Frost, H.M. et al.
Partner: UNT Libraries Government Documents Department