Low energy electron desorption of mixed adsorbates
Hydrogen-nickel reaction in presence of CO adsorbed gas, increasing total desorption cross section and eliminating monotonic relation between uptake and H ion current
Gasser, R. P. H.↗
SEARCH · Engineering Papers
Results for “Adsorbent”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
A transient performance method for CO2 removal with regenerable adsorbents
A computer program is described which can be used to predict the transient performance of vacuum-desorbed sorbent beds for CO2 or water removal, and composite beds of two sorbents for simultaneous humidity control and CO2 removal. The program was written primarily for silica gel and molecular sieve inorganic sorbents, but can be used for a variety of adsorbent materials. Part 2 of this report describes a computer program which can be used to predict performance for multiple-bed CO2-removal sorbent systems. This program is an expanded version of the composite sorbent bed program described in Part 1.
Hwang, K. C.↗
Contaminant removal from enclosed atmospheres by regenerable adsorbents
A system for removing contaminants from spacecraft atmospheres was studied, which utilizes catalyst-impregnated activated carbon followed by in-situ regeneration by low-temperature catalytic oxidation of the adsorbed contaminants. Platinum was deposited on activated carbon by liquid phase impregnation with chloroplatinic acid, followed by drying and high-temperature reduction. Results were obtained for the seven selected spacecraft contaminants by means of three experimental test systems. The results indicate that the contaminants could be removed by oxidation with very little loss in adsorptive capacity. The advantages of a catalyst-impregnated carbon for oxidative regeneration are found to be significant enough to warrent its use.
Goldsmith, R. L.↗
Alteration of an annealed and irradiated lunar fines sample by adsorbed water
Apollo 12 lunar fines sample 12070,403 was annealed at 1000 C and subsequently irradiated with a beam of 130 MeV Fe(9+) ions. Adsorptions of nitrogen and water were measured before and after the irradiation. Prior to the irradiation, the fines were nonporous and water had no effect on the physical characteristics of the lunar fines. In contrast, after the irradiation, the interaction with water caused an increase in the specific surface area and created a pore system. These results are definitive evidence that the interaction of water with damage tracks is the prime factor involved in the alteration of lunar fines by adsorbed water.
Holmes, H. F.↗
Effect of adsorbed films on friction of Al2O3-metal systems
The kinetic friction of polycrystalline Al2O3 sliding on Cu, Ni, and Fe in ultrahigh vacuum was studied as a function of the surface chemistry of the metal. Clean metal surfaces were exposed to O2, Cl2, C2H4, and C2H3Cl, and the change in friction due to the adsorbed species was observed. Auger electron spectroscopy assessed the elemental composition of the metal surface. It was found that the systems exposed to Cl2 exhibited low friction, interpreted as the van der Waals force between the Al2O3 and metal chloride. The generation of metal oxide by oxygen exposures resulted in an increase in friction, interpreted as due to strong interfacial bonds established by reaction of metal oxide with Al2O3 to form the complex oxide (spinel). The only effect of C2H4 was to increase the friction of the Fe system, but C2H3Cl exposures decreases friction in both Ni and Fe systems, indicating the dominance of the chlorine over the ethylene complex on the surface
Pepper, S. V.↗
A dispersion model approach to the preliminary design of adsorber beds for trace contaminants
It is shown that a dispersion model for the transport of a gas through a porous medium can be useful in the preliminary design of adsorber beds for the control of trace contaminants. The transmission function is considered, taking into account the transmission of 102-ppm acetaldehyde in helium flowing at various flow rates through an absorber bed. The experiments were conducted at a temperature of 25.0 C. Attention is given to a representation of the experimental breakthrough curve, the volume adsorption capacity, temperature studies, and correlations.
Madey, R.↗
Two-dimensional O2 adsorbed on graphite
Properties of two-dimensional O2 adsorbed on graphite are calculated in the extremely low-coverage delta region and for monolayers, with use of pattern-recognition optimization and Monte Carlo techniques. Equilibrium configurations and orientations, orientational order-disorder, melting, and dissociation transitions are predicted at various O2 densities. Phase characteristics, including a plastic crystallite phase, are compared with experiment.
Etters, R. D.↗
Adsorbent phosphates
An adsorbent which uses as its primary ingredient phosphoric acid salts of zirconium or titanium is presented. Production methods are discussed and several examples are detailed. Measurements of separating characteristics of some gases using the salts are given.
Watanabe, S.↗
Electron scattering distributions as a probe of adsorbate orientation - CO and N2
The differential cross section for elastic electron scattering by adsorbed CO and N2 is calculated. The dependence of this cross section on the azimuthal angle of detection depends on the molecular orientation and can be used to differentiate between a molecule lying flat on the surface, a tilted molecule, and an upright one. For molecules lying flat on the surface, the orientation of the molecular axis and of the C and O atoms with respect to the plane of incidence of the electron can be determined.
Nagano, S.↗
Adsorbent Removes Traces Of Oxygen
An adsorbent, carbon molecular sieve containing copper oxide, selectively removes oxygen from gas mixtures, producing gas containing less than 1 part per billion of oxygen. Used to help prevent oxidation of chemicals being prepared in dry boxes or to extract undesired traces of oxygen from inert-gas chambers in which flammable gases are stored.
Sharma, Pramod K.↗
The effective thermal conductivity of an adsorbent - Praseodymium cerium oxide
The results of an experimental study to determine the effective thermal conductivity of praseodymium cerium oxide are reported. Praseodymium cerium oxide is an adsorbent used in the development of adsorption compressors for spaceborne refrigeration systems. A guarded-hot-plate apparatus was built for this study. Measurements were carried out for mean temperatures ranging from 300 to 600 C under a vacuum of 10 exp -5 torr. For the temperature range studied, the effective thermal conductivity increased from 0.14 to 0.76 W/m per C with increasing temperature, while displaying a cubic temperature dependency.
Secary, J. J.↗
Tests And Mathematical Modeling Of An Adsorbent Bed
Four reports describe various aspects of mathematical-modeling and experimental study of solid amine regenerative adsorbent bed.
Edeen, Marybeth↗
Unoccupied electronic resonances of Sc adsorbed on W(001) by k-resolved inverse photoemission
Scandium adsorbed on the (001) face of tungsten has been studied using Auger-electron spectroscopy, low-energy electron diffraction, k-resolved inverse photoelectron spectroscopy, work-function measurements, and relativistic-electronic-structure calculations. We find that the work function of W(001) does not decrease monotonically as a function of scandium adsorption but reaches a minimum value of Phi = 3.25 eV at 50% coverage. For a complete monolayer, an order 1 X 1 Sc overlayer is formed. Inverse photoemission in the isochromat mode was used to map the unoccupied energy levels of this overlayer along the bar-Gamma(bar-Mu) symmetry direction of the surface Brillouin zone. Local-density-functional calculations using the muffin-tin orbital method were performed for a 1 X 1 Sc overlayer on W and are compared with the experimental two-dimensional band structure.
Lamouri, A.↗
Effect of Adsorbed Nitrogen on the Thermionic Emission from Lanthanum Hexaboride
The emission properties of lanthanum hexaboride in an atmosphere of nitrogen were investigated. The emitter was not poisoned by adsorbed nitrogen. This result should have application to magnetohydrodynamic devices in which electron flow from channel walls is required.
Carter, Arlen F.↗
Formation of Adsorbed Oxygen Radicals on Minerals at the Martian Surface and the Decomposition of Organic Molecules
We present experimental evidence that superoxide ions form on mineral grains at the martian surface and show that these adsorbates can explain the unusual reactivity of the soil as well as the apparent absence of organic molecules.
Yen, A. S.↗
Process for producing an activated carbon adsorbent with integral heat transfer apparatus
A process for producing an integral adsorbent-heat exchanger apparatus useful in ammonia refrigerant heat pump systems. In one embodiment, the process wets an activated carbon particles-solvent mixture with a binder-solvent mixture, presses the binder wetted activated carbon mixture on a metal tube surface and thereafter pyrolyzes the mixture to form a bonded activated carbon matrix adjoined to the tube surface. The integral apparatus can be easily and inexpensively produced by the process in large quantities.
Jones, Jack A.↗
Recognizing Sulfate and Phosphate Complexes Adsorbed onto Nanophase Weathering Products on Mars
Nanophase weathering products (i.e., secondary phases that lack long-range atomic order) have been recognized on the martian surface via orbital observations and in-situ measurements from landed missions. Allophane, a poorly crystalline, hydrated aluminosilicate, has been identified at the regional scale in models of thermal-infrared (TIR) data from the Thermal Emission Spectrometer (TES) and at the local scale from visible/near-IR (VNIR) data from the Compact Reconnaissance Impact Spectrometer for Mars (CRISM) instrument and phase calculations of Alpha Particle X-ray Spectrometer (APXS) data of rocks encountered by the Mars Exploration Rovers (MER) Spirit and Opportunity. Nanophase iron oxides (npOx) have been recognized in rocks and soils measured by the Mössbauer Spectrometer on Spirit and Opportunity. Furthermore, analyses of X-ray diffraction data measured by the CheMin instrument onboard the Mars Science Laboratory rover Curiosity indicate rock and soil samples are comprised of approx. 20-50 wt.% X-ray amorphous materials. Chemical measurements by landed missions indicate the presence of sulfur and phosphorus in martian rocks in soils, and APXS data from Gusev crater demonstrate abundances of up to approx. 5 wt.% P2O5 and approx. 30 wt.% SO3. However, the speciation of phosphorus and sulfur is not always evident. On Earth, phosphate and sulfate anions can be chemisorbed onto the surfaces of nanophase weathering products. This process may also occur on Mars, and calculations of the composition of the amorphous component at Gale crater using CheMin mineral models and APXS data show that amorphous material is enriched in volatiles, including S. Here, we examine the ability to detect chemisorbed sulfate and phosphate complexes by analyzing sulfate- and phosphate-adsorbed nanophase weathering products using instruments similar to those on landed and orbital missions.
Rampe, E. B.↗
Role of the Tenax® Adsorbent in the Interpretation of the EGA and GC‐MS Analyses Performed With the Sample Analysis at Mars in Gale Crater
The Sample Analysis at Mars (SAM) experiment on the National Aeronautics and Space Administration Curiosity rover seeks evidence of organic compounds on the surface of Mars. Since the beginning of the mission, various organic molecules have been detected and identified. While several have been demonstrated to be indigenous to the Martian soil and rocks analyzed, others appear to have been produced from sources internal to the experiment. The objective of this study is to build an exhaustive molecular database to support the interpretation of SAM results by identifying all the chemical species produced from Tenax® adsorbents, by determining (1) the thermal degradation by‐products of Tenax®, (2) the effect of Tenax® conditioning on the formation of Tenax® by‐products, (3) the impact of MTBSTFA or a mixture of MTBSTFA and DMF on Tenax® decomposition, and (4) the reaction between Tenax® and calcium perchlorate. Our results indicate that the by‐products of the SAM trap are due to the impact of trap heating, the impact of the derivatization reagent (MTBSTFA) and the presence of perchlorate in Martian soil. Some of these by‐products are observed in the SAM gas chromatograph mass spectrometer data from Mars.
Buch, A.↗