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Lawson, D. D.

Publications and source records attributed to Lawson, D. D..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Safety hazards associated with the charging of lithium/sulfur dioxide cells

A continuing research program to assess the responses of spirally wound, lithium/sulfur dioxide cells to charging as functions of charging current, temperature, and cell condition prior to charging is described. Partially discharged cells that are charged at currents greater than one ampere explode with the time to explosion inversely proportional to the charging current. Cells charged at currents of less than one ampere may fail in one of several modes. The data allows an empirical prediction of when certain cells will fail given a constant charging current.

Frank, H.↗
NASA NTRS1984

Estimating the Solubility of Gases in Battery Electrolytes

Estimates in excellent agreement with experimental values. Simple method proposed for estimating solubility of gases in electrolytes of lithium batteries using expressions for energy of vaporization and for molar volume.

Lawson, D. D.↗
NASA NTRS1983

Supercritical multicomponent solvent coal extraction

The yield of organic extract from the supercritical extraction of coal with larger diameter organic solvents such as toluene is increased by use of a minor amount of from 0.1 to 10% by weight of a second solvent such as methanol having a molecular diameter significantly smaller than the average pore diameter of the coal.

Corcoran, W. H.↗
NASA NTRS1982

Heat-Exchange Fluids for Sulfuric Acid Vaporizers

Some fluorine-substituted organic materials meet criteria for heat-exchange fluids in contact with sulfuric acid. Most promising of these are perfluoropropylene oxide polymers with degree of polymerization (DP) between 10 and 50. It is desirable to have DP in high range because vapor pressure of material decreases as DP increases, and high-DP liquids have lower loss due to vaporization.

Lawson, D. D.↗
NASA NTRS1982

Improved Estimates of Thermodynamic Parameters

Techniques refined for estimating heat of vaporization and other parameters from molecular structure. Using parabolic equation with three adjustable parameters, heat of vaporization can be used to estimate boiling point, and vice versa. Boiling points and vapor pressures for some nonpolar liquids were estimated by improved method and compared with previously reported values. Technique for estimating thermodynamic parameters should make it easier for engineers to choose among candidate heat-exchange fluids for thermochemical cycles.

Lawson, D. D.↗
NASA NTRS1982

A New Use for High-Sulfur Coal

New process recovers some of economic value of high-sulfur coal. Although high-sulfur content is undesirable in most coal-utilization schemes (such as simple burning), proposed process prefers high-sulfur coal to produce electrical power or hydrogen. Potential exists for widespread application in energy industry.

Lawson, D. D.↗
NASA NTRS1982

Thermochemical generation of hydrogen

The direct fluid contact heat exchange with H2SO4 at about 330 C prior to high temperature decomposition at about 830 C in the oxygen release step of several thermochemical cycles for splitting water into hydrogen and oxygen provides higher heat transfer rates, savings in energy and permits use of cast vessels rather than expensive forged alloy indirect heat exchangers. Among several candidate perfluorocarbon liquids tested, only perfluoropropylene oxide polymers having a degree of polymerization from about 10 to 60 were chemically stable, had low miscibility and vapor pressure when tested with sulfuric acid at temperatures from 300 C to 400 C.

Lawson, D. D.↗
NASA NTRS1982

Solubility of Sulfur Dioxide in Sulfuric Acid

The solubility of sulfur dioxide in 50% (wt./wt.) sulfuric acid was evaluated by regular solution theory, and the results verified by experimental measurements in the temperature range of 25 C to 70 C at pressures of 60 to 200 PSIA. The percent (wt./wt.) of sulfur dioxide in 50% (wt./wt.) sulfuric acid is given by the equation %SO2 = 2.2350 + 0.0903P - 0.00026P 10 to the 2nd power with P in PSIA.

Chang, K. K.↗
NASA NTRS1981

Superconductivity, cohesive energy density, and electron-atom ratio in metals

It is shown that superconductivity above 8 K occurs in alloys and metallic compounds within relatively narrow regions of cohesive energy density with a sharp peak which includes Nb3Ge, SiV3, Nb3Ga, and NbN. When cross-correlated with the electron-atom ratio, high-temperature superconductivity can be observed in only a few regions. This suggests a search for superconductors with high-transition temperatures and critical fields within these regions.

England, C.↗
NASA NTRS1981

Recent work in advanced hydrogen production concepts

The hydrogen photoelectrolytic conversion activity investigated the practicability of semiconductor electrolytic devises that use solar energy to decompose water into hydrogen and oxygen in an apparent single step process. The photocatalytic decomposition of inorganic hydrogen compounds; i.e., hydrobromic and hydriodic acids using rhodium organic bridge complexes were also studied. The feasibility of direct high temperature thermal decompositions of water with diffusion processes for separation of the equilibrium mixture of hydrogen and oxygen into usable energy sources was examined.

Lawson, D. D.↗
NASA NTRS1981

Potential heat exchange fluids for use in sulfuric acid vaporizers

A series of liquids have been screened as candidate heat exchange fluids for service in thermochemical cycles that involve the vaporization of sulfuric acid. The required chemical and physical criteria of the liquids is described with the results of some preliminary high temperature test data presented.

Lawson, D. D.↗
NASA NTRS1980

Methods of calculating engineering parameters for gas separations

A group additivity method has been generated which makes it possible to estimate, from the structural formulas alone, the energy of vaporization and the molar volume at 25 C of many nonpolar organic liquids. From these two parameters and appropriate thermodynamic relationships it is then possible to predict the vapor pressure of the liquid phase and the solubility of various gases in nonpolar organic liquids. The data are then used to evaluate organic and some inorganic liquids for use in gas separation stages or as heat exchange fluids in prospective thermochemical cycles for hydrogen production.

Lawson, D. D.↗
NASA NTRS1979

Methods for calculation of engineering parameters for gas separation

A group additivity method is generated which allows estimation, from the structural formulas alone, of the energy of vaporization and the molar volume at 25 C of many nonpolar organic liquids. Using these two parameters and appropriate thermodynamic relations, the vapor pressure of the liquid phase and the solubility of various gases in nonpolar organic liquids are predicted. It is also possible to use the data to evaluate organic and some inorganic liquids for use in gas separation stages or liquids as heat exchange fluids in prospective thermochemical cycles for hydrogen production.

Lawson, D. D.↗
NASA NTRS1979

Potential heat exchange fluids for use in sulfuric acid vaporizers

A series of perhalocarbons are proposed as candidate heat exchange fluids for service in thermochemical cycles for hydrogen production that involve direct contact of the fluid with sulfuric acid and vaporization of the acid. The required chemical and physical criteria of the liquids are described and the results of some preliminary high temperature test data are presented.

Lawson, D. D.↗
NASA NTRS1979

Coal mining with a liquid solvent

Study suggests carbonated water can dissolve or suspend coal and carry it to surface. Mixture of carbon dioxide and water may be coal solvent that will make unmanned mining reality. When used with proposed process monitoring coal solubility with conventional strain gage, solvent is basis for rapid cost effective extraction of coal from underground seams.

Lawson, D. D.↗
NASA NTRS1978

Dual membrane hollow fiber fuel cell and method of operating same

A gaseous fuel cell is described which includes a pair of electrodes formed by open-ended, ion-exchange hollow fibers, each having a layer of metal catalyst deposited on the inner surface and large surface area current collectors such as braided metal mesh in contact with the metal catalyst layer. A fuel cell results when the electrodes are immersed in electrolytes and electrically connected. As hydrogen and oxygen flow through the bore of the fibers, oxidation and reduction reactions develop an electrical potential. Since the hollow fiber configuration provides large electrode area per unit volume and intimate contact between fuel and oxidizer at the interface, and due to the low internal resistance of the electrolyte, high power densities can be obtained.

Ingham, J. D.↗
NASA NTRS1978

Fire-and smoke-retardant polyesters and elastomers

Test results indicate that most effective fire-and smoke-retardant fillers are inorganic hydrates and carbonates that release water and/or carbon dioxide. Most effective filler tested was hydrated sodium silicate. Effectiveness is due to high water content and formation of viscous molten glass when heated. Glass tends to inhibit polymer combustion and to promote formation of char residue.

Chung, S. Y.↗