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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Soluble minerals in chemical evolution. I - Adsorption of 5-prime-AMP on CaSO4 - A model system

The adsorption of 5-prime-AMP onto solid CaSO4-2H2O was studied in a saturated suspension as a function of pH and electrolyte concentration. The adsorption is pH-dependent and is directly correlated with the charge on the 5-prime-AMP molecule which is determined by the state of protonation of the N-1 nitrogen of the purine ring and the phosphate oxygens. It is proposed that the binding that occurs between the nucleotide and the salt is electrostatic in nature. The adsorption decreases with increasing ionic strength of the solution which means that in a fluctuating environment of wetting and drying cycles, a biomolecule similar to 5-prime-AMP could be expected to desorb during the drying phase. The results indicate that CaSO4-2H2O can serve as a concentrating surface for biomolecules. The significance of this is discussed with regard to the possible role of soluble minerals and their surfaces in a geochemical model consistent with the evolution of the earth and the origin of life.

Orenberg, J. B.↗
NASA NTRS1993

Impact-induced devolatilization of CaSO4 anhydrite and implications for K-T extinctions: Preliminary results

The recent suggestions that the target area for the K-T bolide may have been a sulfate-rich evaporite and that the resulting sulfuric acid-rich aerosol was responsible for the subsequent cooling of the Earth and the resulting biological extinctions has prompted us to experimentally examine the impact-induced devolatization of the sulfate minerals anhydrite (CaSO4) and gypsum (CaSO4(2H2O)). Preliminary results for anhydrite are reported. Up to 42 GPa peak shock pressure, little or no devolatilization occurs, consistent with chemical thermodynamic calculations. Calculation of the influence of the partial pressure of the gas species on impact-induced devolatilization suggests that an even greater amount of sulfur than that proposed by Brett could have been released to the atmosphere by an impact into a sulfate-rich layer. Solid recovery, impact-induced devolatilization experiments were performed on the Caltech 20mm gun using vented, stainless steel sample assemblies.

Tyburczy, James A.↗
DOE OSTI2020

Materials Data on CaSO4 by Materials Project

CaSO4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ca2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ca–O bond distances ranging from 2.44–2.88 Å. S6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of S–O bond distances ranging from 1.48–1.50 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one S6+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one S6+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one S6+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ca2+ and one S6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaSO4 by Materials Project

CaSO4 is Zircon-like structured and crystallizes in the hexagonal P6_222 space group. The structure is three-dimensional. Ca2+ is bonded to eight equivalent O2- atoms to form distorted CaO8 hexagonal bipyramids that share corners with four equivalent SO4 tetrahedra, edges with four equivalent CaO8 hexagonal bipyramids, and edges with two equivalent SO4 tetrahedra. There are four shorter (2.41 Å) and four longer (2.57 Å) Ca–O bond lengths. S6+ is bonded to four equivalent O2- atoms to form SO4 tetrahedra that share corners with four equivalent CaO8 hexagonal bipyramids and edges with two equivalent CaO8 hexagonal bipyramids. All S–O bond lengths are 1.49 Å. O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one S6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaSO4 by Materials Project

CaSO4 is Zircon-like structured and crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.38–2.59 Å. S6+ is bonded in a tetrahedral geometry to four O2- atoms. All S–O bond lengths are 1.49 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one S6+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one S6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaSO4 by Materials Project

CaSO4 is Zircon-like structured and crystallizes in the orthorhombic C222 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to eight O2- atoms to form distorted CaO8 hexagonal bipyramids that share corners with four SO4 tetrahedra, edges with four CaO8 hexagonal bipyramids, and edges with two equivalent SO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.40–2.57 Å. In the second Ca2+ site, Ca2+ is bonded to eight O2- atoms to form distorted CaO8 hexagonal bipyramids that share corners with four equivalent SO4 tetrahedra, edges with four equivalent CaO8 hexagonal bipyramids, and edges with two equivalent SO4 tetrahedra. There are four shorter (2.41 Å) and four longer (2.57 Å) Ca–O bond lengths. There are two inequivalent S6+ sites. In the first S6+ site, S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with four CaO8 hexagonal bipyramids and edges with two equivalent CaO8 hexagonal bipyramids. All S–O bond lengths are 1.49 Å. In the second S6+ site, S6+ is bonded to four equivalent O2- atoms to form SO4 tetrahedra that share corners with four equivalent CaO8 hexagonal bipyramids and edges with two equivalent CaO8 hexagonal bipyramids. All S–O bond lengths are 1.49 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two Ca2+ and one S6+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two Ca2+ and one S6+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one S6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaSO4 by Materials Project

CaSO4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.58 Å. S6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of S–O bond distances ranging from 1.47–1.50 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and one S6+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one S6+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one Ca2+ and one S6+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS1984

An Investigation of the Adsorption Characteristics of 5'ATP and 5'AMP onto the Surface of Caso4 x 2H2O

A model has been proposed in which solid surfaces can act as a site for cataletic activity of condensation reactions for certain biomolecules. From this model, the adsorption characteristics of 5'ATP and 5'AMP onto the surface of CaSO4.2H2O was chosen for study. It has been proven that 5'ATP and 5'AMP do adsorb onto the surface of CaSO4. Studies were then made to determine the dependence of absorption versus time, concentration, ionic strength and pH. It was found that the adsorption of the nucleotides is highly pH dependent, primarily determined by the phosphate acid groups of the nucleic acid molecule. From this investigation, the data obtained is discussed in relation to the model for the prebiotic earth.

Calderon, J.↗
NASA NTRS1993

Shock induced reaction in Chicxulub target materials (CaSO4 and SiO2) and their relation to extinctions

The global platinum element rich layer, the presence of shocked quartz grains (in some cases with stishovite), and the observation of a tektite-rich layer, precisely at the K-T boundary, are the three major arguments for the extinction bolide impact hypothesis of Alvarez et al. Tektites (spherules) from Beloc in Haiti and Mimbral in Mexico received particular interest because of their geological proximity to the Chicxulub impact structure, which is a leading candidate for at least one of the K-T impact craters. Although in most localities the original glass has weathered to clay minerals, some shock-induced glass is found in outcrops and drill cores which is used for Ar-38/Ar-39 dating. The glassy tektites were found to be chemically similar and coeval at 65.0 Ma with Chicxulub melt rock. Two kinds of K-T spherules were discovered: (1) a silic black glass; and (2) a yellow glass, enriched in Ca, Mg, and S. The high sulfur content of the glass and the abundance of anhydrite (CaSO4) in the carbonate-evaporite sequence observed in Drill Holes Y-1 and Y-2 at Chicxulub prompted studies of calcium sulfate devolatization. Further discussion of our experiments is presented.

Chen, Guangqing↗
NASA NTRS1986

An investigation of the adsorption characteristics of 5 prime ATP and 5 prime AMP onto the surface of CaSO sub 4 x 2H sub 2 O

A model has been proposed (Lahev and Chans, 1982) in which solid surfaces can act as a site for catalytic activity of condensation reactions for certain biomolecules. From this model, the adsorption characteristics of 5'ATP and 5'AMP onto the surface of CaSO4 2H2O was chosen for study. It has been proven that 5'ATP and 5'AMP do adsorb onto the surface of CaSO4. Studies were then made to determine the dependence of adsorption versus time, concentration, ionic strength and pH. It was found that the adsorption of the nucleotides is highly pH dependent, primarily determined by the phosphate acid groups of the nucleic acid molecule. From this investigation, the data obtained are discussed in relation to the model for the prebiotic earth.

Calderon, J.↗
NASA NTRS1992

The Chemistry of Saudi Arabian Sand - A Deposition Problem on Helicopter Turbine Airfoils

Operations in the Persian Gulf have exposed military helicopter turbines to excessive amounts of ingested sand. Fine particles, less than 10 microns, are able to bypass the particle separators and enter the cooling and combustion systems. The initial sand chemistry varies by location, but is made up of a calcium aluminum silicate glass, SiO2 low quartz, (Ca,Mg)CO3 dolomite, CaCO3 calcite, and occasionally NaCl rocksalt. The sand reacts in the hot combustion gases and deposits onto the turbine vanes as CaSO4, glass, and various crystalline silicates. Deposits up to 5 mm thick have been collected. Although cooling hole plugging is a considerable problem, excessive corrosion is not commonly observed due to the high melting point of CaSO4.

Smialek, James L.↗
NASA NTRS1993

Crustal structure and igneous processes in a chondritic Io

Liquid sulfur can form when metal-free C1 or C2 chondrites are heated. It may be obtained either by direct melting of native sulfur in disequilibrated C1 or C2 chondrites or by incongruent melting of pyrite and other sulfides in thermodynamically equilibrated rocks of the same composition. Hence, Lewis considered C2 chondrites to be the best meteoritic analog for Io's bulk composition. Metal-bearing C3 and ordinary chondrites are too chemically reduced to yield liquid sulfur and are not thought to represent plausible analogs of Io's bulk composition. An important aspect of Lewis' work is that CaSO4 and MgSO4 are predicted to be important in Io. Real C1 and C2 chondrites contain averages of, respectively, 11 percent and 3 percent by mass of salts (plus water of hydration). The most abundant chondritic salts are magnesium and calcium sulfates, but other important components include sulfates of sodium, potassium, and nickel and carbonates of magnesium, calcium, and iron. It is widely accepted that chondritic salts are formed by low-temperature aqueous alteration. Even if Io originally did not contain salts, it is likely that aqueous alteration would have yielded several percent sulfates and carbonates. In any event, Io probably contains sulfates and carbonates. This report presents the results of a model of differentiation of a simplified C2 chondrite-like composition that includes 1.92 percent MgSO4, 0.56 percent CaSO4, 0.53 percent CaCO3, and 0.094 percent elemental sulfur. The temperature of the model is gradually increased; ensuing fractional melting results in these components extruding or intruding at gravitationally stable levels in Io's crust. Relevant phase equilibria were reviewed. A deficiency of high-pressure phase equilibria renders the present model qualitative.

Kargel, J. S.↗
NASA NTRS1993

Shock-induced devolatization of calcium sulfate and implications for K-T extinctions

Calcium sulfate devolatization during the impact at Chicxulub, Mexico and dispersal in the stratosphere of the resultant sulfuric acid aerosol have been suggested as a possible mechanism for the Cretaceous-Tertiary extinctions. In this paper, we investigated two shock-induced devolatization reactions of calcium sulfate up to 42 GPa in the laboratory: CaSO4 + SiO2 yields CaSiO3 + SO3(degassed) and CaSO4 yields CaO + SO2(degassed) + 1/2 O2(degassed). We found both to proceed to a much less extent than calculated by equilibrium thermodynamic calculations. Reaction products are found to be 10(exp -2) times those calculated for equilibrium. Consequently our estimate of the amount of sulfur oxides degassed into the atmosphere from shock devolatization of CaS04 in the Chicxulub lithographic section (6x10(exp 15)-2x10(exp 16)g in sulfur mass) is lower by a factor of 70 to 400 than previous estimates; the related environmental stress arising from the resultant global cooling of approximately 4 K and fallout of acid rain does not appear to suffice to explain the widespread K-T extinctions.

Chen, Guangqing↗
NASA NTRS1994

Carbonates and sulfates in the Chassigny meteorite: Further evidence for aqueous chemistry on the SNC parent planet

Scanning electron microscopy and energy-dispersive X-ray spectrometry of untreated interior chips from three different specimens of the Chassigny meteorite confirm the presence of discrete grains of Ca-carbonate, Mg-carbonate, and Ca-sulfate. Morphologies of these salt grains suggest that the Ca-carbonate is calcite (CaCO3) and that the Ca-sulfate is gypsum (CaSO4-2H2O) or bassanite (CaSO4-1/2H2O). The morphologic identification of the Mg-carbonate is equivocal, but rhombohedral and acicular crystal habits suggest magnesite and hydromagnesite, respectively. The salts in Chassigny occur as discontinuous veins in primary igneous minerals and are similar to those previously documented in the nakhlites, Nakhla and Lafayette, and in shergottite EETA79001. Unlike those in nakhlites, however, the Chassigny salts occur alone, without associated ferric oxides or aluminosilicates clays. Traces of Cl and P in Chassigny salts are consistent with precipitation of the salts from short-lived, saline, aqueous solutions that postdated igneous crystallization. In contrast with the clear case for nakhlites, stratigraphic evidence for a preterrestrial origin of the salts in Chassigny is ambiguous; however, a preterrestrial origin of the Chassigny salts best explains all available evidence. The water-precipitated salts provide clear physical evidence for the hypothesis, proposed by other workers, that the igneous amphiboles in Chassigny might have experienced isotope-exchange reactions with near-surface water, thereby compromising the original stable-isotope signature of any magmatic water in melt inclusions.

Wentworth, Susan J.↗
NASA NTRS1999

Extra dose due to extravehicular activity during the NASA4 mission measured by an on-board TLD system

A microprocessor-controlled on-board TLD system, 'Pille'96', was used during the NASA4 (1997) mission to monitor the cosmic radiation dose inside the Mir Space Station and to measure the extra dose to two astronauts in the course of their extravehicular activity (EVA). For the EVA dose measurements, CaSO4:Dy bulb dosemeters were located in specially designed pockets of the ORLAN spacesuits. During an EVA lasting 6 h, the dose ratio inside and outside Mir was measured. During the EVA, Mir crossed the South Atlantic Anomaly (SAA) three times. Taking into account the influence of these three crossings the mean EVA/internal dose rate ratio was 3.2. Internal dose mapping using CaSO4:Dy dosemeters gave mean dose rates ranging from 9.3 to 18.3 microGy h-1 at locations where the shielding effect was not the same. Evaluation results of the high temperature region of LiF dosemeters are given to estimate the mean LET.

NASA Experiment Number 9401704↗
DOE OSTI2022

Desalinating a Real Hyper-Saline Pre-Treated Produced Water via Direct-Heat Vacuum Membrane Distillation

Membrane distillation (MD) is an emerging thermal desalination technology capable of desalinating waters of any salinity. During typical MD processes, the saline feedwater is heated and acts as the thermal energy carrier; however, temperature polarization (as well as thermal energy loss) contributes to low distillate fluxes, low single-pass water recovery and poor thermal efficiency. An alternative approach is to integrate an extra thermal energy carrier as part of the membrane and/or module assembly, which can channel externally provided heat directly to the membrane-feedwater interface and/or along the feed channel length. This direct-heat delivery has been demonstrated to increase single-pass water recovery and enhance the overall thermal efficiency. We developed a bench-scale direct-heated vacuum MD (DHVMD) process to desalinate pre-treated oil and gas "produced water" with an initial total dissolved solids of 115,500 ppm at a feed temperature ranging between 24 and 32 degrees C. We evaluated both water flux and specific energy consumption (SEC) as a function of water recovery. The system achieved a 50% water recovery without significant scaling, with an average flux >6 kg m-2 hr-1 and a SEC as low as 2,530 kJ kg-1. The major species of mineral scales (i.e., NaCl, CaSO4, and SrSO4) that limited the water recovery to 68% were modeled in terms of thermodynamics and identified by scanning electron microscopy and energy-dispersive X-ray spectroscopy. In addition, we further developed and employed a physics-based process model to estimate temperature, salinity, water transport and energy flows for full-scale vacuum MD and DHVMD modules. Model results show that a direct-heat input rate of 3,600 W can increase single-pass water recovery from 2.1% to 3.1% while lowering the thermal SEC from 7,800 kJ kg-1 to 6,517 kJ kg-1 in an unoptimized module. Finally, the scaling up potential of DHVMD process is briefly discussed.

brine↗
DOE OSTI2024

Influence of zwitterionic amphiphilic copolymers on heterogeneous gypsum formation: A promising approach for scaling resistance

Here, this study aims to investigate the influence of zwitterionic amphiphilic copolymers (ZACs) in the nucleation and growth of heterogeneous CaSO4 at the zwitterion-water interface, which is crucial for the prevention of mineral scaling and consequent downtime or suboptimal performance in industries like membrane desalination, heat exchangers, and pipeline transportation. In situ grazing incidence small angle X-ray Scattering (GISAXS), and quartz crystal microbalance with dissipation (QCM-D) techniques were used to analyze the evolution of CaSO 4 particles on two new ZAC coatings: poly-(trifluoroethyl methacrylate-random-sulfobetaine methacrylate) (PTFEMA-r-SBMA, or PT:SBMA) and poly(trifluoroethyl methacrylate-random-2-methacryloyloxyethyl phosphorylcholine) (PTFEMA-r-MPC, or PT:MPC). The results showed that PT:MPC coatings promoted nucleation but inhibited crystal growth, resulting in slower overall reaction kinetics on PT:MPC coatings compared to PT:SBMA coatings. Interfacial interactions involving the substrates, sulfate minerals, and ions were examined, revealing that calcium ion adsorption, primarily governed by electrostatic attraction, played a crucial role in the nucleation and growth processes on both ZAC coatings. The crystal characterization revealed a phase transition from bassanite to gypsum on both ZAC coatings, suggesting that these zwitterionic materials can influence the mineral phase of heterogeneously formed CaSO 4 crystals. These findings enhance our understanding of the fundamental mechanisms underlying heterogeneous CaSO 4 scaling in the presence of zwitterionic materials.

42 ENGINEERING↗