Gas-phase acidities of carbon acids.
Relative gas phase acidities of carbon acids determined using ion cyclotron resonance spectroscopy
Blair, L. K.↗
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The Formation and Stability of Carbonic Acid on Outer Solar System Bodies
The radiation chemistry, thermal stability, and vapor pressure of solid-phase carbonic acid (H2CO3) have been studied with mid-infrared spectroscopy. A new procedure for measuring this molecule's radiation stability has been used to obtain intrinsic IR band strengths and half-lives for radiolytic destruction. Results are compared to literature values. We report, for the first time, measurements of carbonic acid's vapor pressure and its heat of sublimation. We also report the first observation of a chemical reaction involving solid-phase carbonic acid. Possible applications of these findings are discussed, with an emphasis on the outer Solar System.
Peeters, Z.↗
Identification and yield of carbonic acid and formaldehyde in irradiated ices
Carbonic acid, (OH)2CO, was tentatively identified in the IR spectrum of a proton irradiated CO2 + H2O ice mixture. In this report, we present additional evidence for a more definitive identification of (OH)2CO with (1) the infrared spectrum of a residue obtained by proton irradiation of CO2 + D2O ice mixture, and (2) the IR spectra of solid phases of formaldehyde (H2CO), acetone (CH3)2CO, and dimethyl carbonate (OCH3)2CO, which are structurally similar to (OH)2CO. IR characteristics (peak frequencies and complex refractive indices of the compounds in point 2) are also reported. In particular, the integrated absorption coefficients for the C-O band for the compounds in point 2 do not vary by more than 20 percent. Based on these values, we estimate the yields of H2CO and (OH)2CO by proton irradiation or ice mixtures. Both H2CO and (OH)2CO are possible irradiation products of cometary and planetary ices.
Dellorusso, Neil↗
Heat exchange in the supercritical region during the flow of piped carbonic acid and water
Experimental study on local heat transfer during turbulent flow of piped carbonic acid and water in supercritical region with state variables
SUPERCRITICAL PRESSURE↗
Possible recent and ancient glacial ice flow in the south polar region of Mars
Martian polar science began almost as soon as small telescopes were trained on the planet. The seasonal expansion and contraction of the polar caps and their high albedoes led most astronomers to think that water ice is the dominant constituent. In 1911 Lowell perceived a bluish band around the retreating edge of the polar caps, and interpreted it as water from melting polar ice and seasonal snow. An alternative idea in his time was that the polar caps consist of frozen carbonic acid. Lowell rejected the carbonic acid hypothesis on account of his blue band. He also pointed out that carbonic acid would sublimate rather than melt at confining pressures near and below one bar, hence, carbonic acid could not account for the blue band. In comparing Lowell's theories with today's knowledge, it is recognized that (1) sublimation is mainly responsible for the growth and contraction of Mars' polar caps, (2) carbon dioxide is a major component of the southern polar cap, and (3) Lowell's blue band was probably seasonal dust and/or clouds. Geomorphic evidence that glacial ice and glacial melt waters once flowed over broad areas of the southern polar region. Two aspects of the south polar region suggest possible glacial processes during two distinct eras in Mars' history.
Kargel, J. S.↗
The Martian ocean: First acid, then alkaline
In Mars' distant past, carbon dioxide and water may have been plentiful. Values of total outgassed CO2 from several to about 10 bar are consistent with present knowledge, and this amount of CO2 implies an amount of water outgassed equal to an equivalent depth of 500 to 1000 m. It is quite reasonable, therefore, to envision an early Mars in which there was a body or bodies of liquid water, perhaps in the northern plains, and a dense carbon dioxide atmosphere. Under such conditions, the pH of the water will be low, due to the dissolution of carbon dioxide in the water to form carbonic acid. This acidic water is capable of weathering the available rock quite intensely, particularly because this rock is likely to be heavily fractured (from meteorite bombardment) or even consist of fine particles (such as pyroclastic deposits). As time goes on, however, the carbon dioxide atmosphere will rapidly pass through the ocean to form carbonate deposits. As the density of the atmosphere decreases, so will the flux of carbonic acid into the ocean. Without this input of carbonic acid, the effect of the dissolved weathering products will be to increase the pH of the water. The ocean will then become alkaline. To study this process, I have developed a geochemical cycle model for the atmosphere-hydrosphere-regolith system of Mars. The treatment of geochemical cycles as complex kinetic chemical reactions has been undertaken for terrestrial systems in recent years with much success. This method is capable of elegantly handling the interactions between the simultaneous chemical reactions needed to understand such a system.
Schaefer, M. W.↗
Electrochemical performance investigations on the hydrogen depolarized CO2 concentrator
An extensive investigation of anode and cathode polarization in complete cells and half cells was conducted to determine the factors affecting HDC electrode polarization and the nature of this polarization. Matrix-electrolyte-electrode interactions and cell electrolyte composition were also investigated. The electrodes were found to have normal performance capabilities. The HDC anode polarization characteristics were correlated with a theoretical kinetic analysis; and, except for some quantitative details, a rather complete understanding of the causes for HDC electrode polarization was formulated. One of the important finding resulting from the kinetic analysis was that platinum appears to catalyze the decomposition of carbonic acid to carbon dioxide and water. It was concluded that the abnormal voltage performance of the One Man ARS HDC cells was caused by insufficient cell electrolyte volume under normal operating conditions due to deficiencies in the reservoir to cell interfacing.
Aylward, J. R.↗
Venus' Mass Spectra Show Signs of Disequilibria in the Middle Clouds
We present a re‐examination of mass spectral data obtained from the Pioneer Venus Large Probe Neutral Mass Spectrometer. Our interpretations of differing trace chemical species are suggestive of redox disequilibria in Venus' middle clouds. Assignments to the data (at 51.3 km) include phosphine, hydrogen sulfide, nitrous acid, nitric acid, carbon monoxide, hydrochloric acid, hydrogen cyanide, ethane, and potentially ammonia, chlorous acid, and several tentative PxOy species. All parent ions were predicated upon assignment of corresponding fragmentation products, isotopologues, and atomic species. The data reveal parent ions at varying oxidation states, implying the presence of reducing power in the clouds, and illuminating the potential for chemistries yet to be discovered. When considering the hypothetical habitability of Venus' clouds, the assignments reveal a potential signature of anaerobic phosphorus metabolism (phosphine), an electron donor for anoxygenic photosynthesis (nitrite), and major constituents of the nitrogen cycle (nitrate, nitrite, ammonia, and N2).
disequilibria↗
Examining Weathering of Magnesite in an Arid Environment: Implications For Jezero Crater
Introduction:Orbiter data indicatethe presence of carbonates in severallocations on the surface of Mars[1],but Jezero crater, landing site of the Perseverancerover,is the only known location where carbonatesap-pear coincident with evidence of fluvialand lacustrineactivity [2].On Earth, carbonates in close proximity to these paleoenvironments mayindicatethe presence of past microbial life,like stromatolites[3], that could re-sult inbiosignatures [2]. However,in other cases,car-bonates can also form throughthe alteration of mafic materialwiththe introductionof carbonic acid[4].Hy-drated magnesites have also been found in evaporative environments along lake shores, and in playas[5,6,7].Correctly interpreting past carbonates on Mars is there-fore critical in the search for past signs of life. In Jezero crater,both thenorthernand western fans haveMg-rich carbonates intermixed with olivine-rich material[8].According to CRISM data, magnesite(MgCO3), along with hydromagnesite(Mg5(CO3)4(OH)2•4H2O), arepotential candidatesfor these Mg-carbonates [2]. Considering the spatial con-text with olivine,there aremultiplepotential explana-tions for the presence ofMg-carbonatesin this locationincludingin-situformation via alterationof olivine-rich materialwith carbonic acid,transportationfrom farther up in the watershed, or precipitation of lacustrine car-bonates[2]. The formation of hydromagnesite rather than magnesite is favored when Mg2+saturated solutions have a high CO32-/HCO3-ratio, which, on Earth, is thought to be caused byinflow of groundwater [4]. Additionally, Mg-carbonates tend to precipitate under high pH condi-tions and are unstable at lower pH conditions [5]. Hy-dromagnesite is stable at atmospheric CO2pressure and temperature conditions common to most Earth surface environments [9]. However, it is subject to transfor-mation to magnesite after dehydration and concomitant brucite formation or dissolution and reprecipitation [10].Previousresearch suggests that hydrated car-bonates, including hydromagnesite, can formas weath-ering productsof mafic minerals in the presenceof H2O and CO2in subfreezing temperatures and would not de-hydrate under Martian atmospheric conditions [11,12].It is critical to understand the formation conditions of Mg-carbonatesbecause of the different implications for the past history of Martian environments. Therefore, in this work we are investigating the weathering of Mg-carbonatesin arid environments to helpbetter understand Mg-carbonates in Jezero crater. Study Area:The Ala-Mar Mines(East and West)near Ely, NVare the site ofmultiple magnesitedepositsfound within a calcareous tuff formationthat overlies Tertiary aged volcanic rocks.Here,magnesiteis formed via the alteration of the calcareous tuff and occurs innodules, veins,and lenses[13]. Previous work suggests magnesite deposits are associated with faults [13]. Within the West Mine, magnesite can be found in two maincontexts: (1) relatively circular zones of cauli-flower-like material found within (2) a more massivelensthat is heavily fractured on the surface.Methods.Samplesof both the cauliflower texture and more massive materialwere collectedat Ala Mar West Mine. Both samples were thenpowdered, sieved and analyzed with an inXitu Terra Portable XRD. The program QualX was used to identify potential mineral phases [14].Both samples were also optically inspected using 10x and 20x hand lenses.Figure 1. XRD patterns for the cauliflower magnesite (top) and massive magnesite (bottom). Ongoing and future work on the samples discussed above includes scanning electron microscopy (SEM), electron microprobe analysis (EMPA), and near-infra-red spectroscopy to determine whether hydromagnesite is present. Separation and analysis of the clay-size frac-tionby XRD will helpto better identify any phyllosili-cate phases present. Results and Discussion:Both textures are a white to light tan with a porcelain luster on weathered sur-faces, along with minor iron staining in some areas. Likewise, both textures are white with a porcelain luster on fresh surfaces. When broken apart, the massive mag-nesite shows macroscopic crystals, unlike the cauli-flower magnesite. XRD analysis shows that both samples have high concentrationsof magnesite with lesser amounts of thecarbonatemineral huntite(Mg3Ca(CO3)4; Figure1).The more massive samplecontainsa serpentine-groupmineral,with lizardite being apotential candidate. The cauliflower sample has several minor peaks that may correspond to hydromagnesite(Figure 1), although more work is needed to confirm this.Additionally, thecauliflower deposits closely resemble hydromagnesite deposits found in southwestern Turkey, formed via mi-crobialites[15].As such, it is likely that moreaqueous alterationor weatheringis occurring at the locations where the cauliflower magnesite is present. However, additional field work will need to be conducted to con-firm this hypothesis. Conclusions and Future Work:Future work will include field mapping of fault locations andadditional samplingof the different magnesite types as well as of the calcareous tuffmaterial.We will also look specifi-cally for potential weathering products of magnesite in this arid location, which may yield important insight into the Mg-carbonates located in Jezero crater. XRD analyses on aPANalytical XRDusing non-ambient stages will be used to investigate the stability of hydro-magnesiteat different humiditiesand temperatures, which has implications for samples to bereturned to Earth in the future. Additionally, thermal and evolved gas analysis of magnesite and hydromagnesite will be compared to results from Gale Craterto help interpret the mineralogy inthat location[16]. The results of this research will further ourunderstanding of carbonate for-mationin volcanic settingsandtheirweathering pro-cessesin arid environments. Acknowledgments:We acknowledge funding for this research from Jacobs Technology at the Johnson Space Center.We would also like to thank Ngoc Luu, Christopher Adcock, Richard Allanson, and the rest of the UNLV Soil Science Teamfor their continued sup-portwith troubleshooting and otherlab work. References:[1] Ehlmann, B.L., and Edwards, C.S. (2014) Annual Review of Earth and Planetary Sci., 42, 291–315. [2] Horgan, B.H.N., et al. (2020) Icarus, 339, 113526. [3] Bosak, T., et al. (2013) Annual Review of Earth and Planetary Sci, 41, 21–44. [4] Pohl, W.L. (1989) Gebriider Borntraege, 28, 1-13. [5] Müller, G., et al. (1972) Die Naturwissenschaften, 59, 158–164. [6] Walter, M.R., et al. (1973) Journal of Sedimentary Pe-trology, 43, 1021–1030. [7] Braithwaite, C.J.R., and Zedef, V. (1994) Sedimentary Geology, 92, 1–5. [8] Goudge, T.A., et al. (2015) JGR: Planets, 120, 775–808. [9] Langmuir, D. (1965) Journal of Geology, 73, 730–754. [10] Zhang, P., et al. (2000) Applied Geo-chem., 286, 1748–1753. [11] Calvin, W.M., et al. (1994) JGR, 99, 14659-14675. [12]Russell, M.J., et al. (1999) Journal of the Geological Society of London, v. 156, p. 869–888. [13] Faust, G.T., and Callaghan, E. (1948) GSA Bulletin, 59, 11–74. [14] Altomare, A., et al. (2015) J. of Applied Crystallography, 48, 598–603. [15] Zedef, V.,et al. (2000) Economic Geology, 95, 429–445. [16] Leshin, L.A. et al., (2013) Science, 341, 1–9
A W Provow↗
A New Method of Testing in Wind Tunnels
Now, in existing wind tunnels, using a horsepower of 100 to 300, the models are generally made to a 1/10 scale and the speed is appreciably lower than the speeds currently attained by airplanes. The Reynolds number realized is thus 15 to 25 times smaller than that reached by airplanes in free flight, while the ratio of speed to the velocity of sound is between a third and three quarters of the true ratio. The necessary increases in either the diameter of the wind tunnel or the velocity of the airstream are too costly. However, the author shows that it is possible to have wind tunnels in which the Reynolds number will be greater than that now obtained by airplanes, and in which the ratio of the velocity to the velocity of sound will also be greater than that realized in practice, by employing a gas other than air, at a pressure and temperature different from those of the surrounding atmosphere. The gas is carbonic acid, a gas having a low coefficient of viscosity, high density, and a low ratio of specific heat. The positive results of using carbonic acid in wind tunnel tests are given.
Margoulis, W↗
On the location of acid-hydrolysable carbon in lunar soil fines
Soil fines exposed on the lunar surface accumulate small metallic iron particles and solar wind-derived carbon. In previous work, it has been suggested that an intimate association exists between one particular carbon phase, hydrolysable carbon, and very fine iron droplets, where the carbon is in solid solution in the iron. The earlier hypothesis of a constant carbon in iron concentration across a broad range of droplet sizes is testable by combining hydrolysable carbon determinations with a variety of magnetic measurements sensitive to different droplet diameters. New measurements of ferromagnetic resonance response on density and magnetic separates from size fractions of soil 12023 are interpreted as evidence that hydrolysable carbon is preferentially associated with the larger, magnetically stable single-domain iron particles rather than with the smaller superparamagnetic droplets. For the former, there is a quite uniform ratio of iron to carbon both within a series of separates from a single soil, and among soils of widely varying FeO content.
Fallick, A. E.↗
Acid dissolution experiments - Carbonates and the 6.8-micrometer bands in interplanetary dust particles
A chemical dissolution experiment on an interplanetary dust particle (IDP) showed that carbonates, not acid-insoluble organic compounds, were responsible for virtually all the absorption at 6.8 micrometers seen in the infrared spectra of this particle. The IDP examined had an infrared spectrum characteristic of layer-lattice silicates and belongs to a class of IDP's whose spectra resemble those of protostellar objects like W33 A, which also exhibit a band at 6.8 micrometers.
Sandford, S. A.↗
Response of marine and freshwater algae to nitric acid and elevated carbon dioxide levels simulating environmental effects of bolide impact
One of the intriguing facets of the Cretaceous-Tertiary extinction is the apparently selective pattern of mortality amongst taxa. Some groups of organisms were severely affected and some remained relatively unscathed as they went through the K/T boundary. While there is argument concerning the exact interpretation of the fossil record, one of the best documented extinctions at the Cretaceous-Tertiary boundary is that of the calcareous nannoplankton. These organisms include coccolithic algae and foraminiferans. Attempts to explain their decline at the K/T boundary center around chemistry which could affect their calcium carbonate shells while leaving their silica-shelled cousins less affected or unaffected. Two environmental consequences of an extraterrestrial body impact which were suggested are the production of large quantities of nitrogen oxides generated by the shock heating of the atmosphere and the possible rise in CO2 from the dissolution of CaCO3 shells. Both of these phenomena would acidify the upper layers of the oceans and bodies of freshwater not otherwise buffered. The effects of nitric acid, carbon dioxide, or both factors on the growth and reproduction of calcareous marine coccoliths and non-calcareous marine and freshwater species of algae were considered. These experiments demonstrate that nitric acid and carbon dioxide have significant effects on important aspects of the physiology and reproduction of modern algae representative of extinct taxa thought to have suffered significant declines at the Cretaceous-Tertiary boundary. Furthermore, calcareous species showed more marked effects than siliceous species and marine species tested were more sensitive than freshwater species.
Boston, P. J.↗
Binder for Carbon-Fiber Coating
Insoluble, even coating formed by soaking in polyacrylic acid. Carbon fiber material prepared by soaking in solution of 20 percent polyacrylic acid in water. Material blotted and dried at 120 degrees C for at least 2 hours. Dried material reacted with boiling aqueous solution of calcium acetate. Treated material removed from boiling solution, blotted, dried at 120 degrees C, washed with distilled water, and dried again.
Dowler, W. L.↗
Investigating CO2 Reservoirs at Gale Crater and Evidence for a Dense Early Atmosphere
One of the most compelling features of the Gale landing site is its age. Based on crater counts, the formation of Gale crater is dated to be near the beginning of the Hesperian near the pivotal Hesperian/Noachian transition. This is a time period on Mars that is linked to increased fluvial activity through valley network formation and also marks a transition from higher erosion rates/clay mineral formation to lower erosion rates with mineralogies dominated by sulfate minerals. Results from the Curiosity mission have shown extensive evidence for fluvial activity within the crater suggesting that sediments on the floor of the crater and even sediments making up Mt. Sharp itself were the result of longstanding activity of liquid water. Warm/wet conditions on early Mars are likely due to a thicker atmosphere and increased abundance of greenhouse gases including the main component of the atmosphere, CO2. Carbon dioxide is minor component of the Earth's atmosphere yet plays a major role in surface water chemistry, weathering, and formation of secondary minerals. An ancient martian atmosphere was likely dominated by CO2 and any waters in equilibrium with this atmosphere would have different chemical characteristics. Studies have noted that high partial pressures of CO2 would result in increased carbonic acid formation and lowering of the pH so that carbonate minerals are not stable. However, if there were a dense CO2 atmosphere present at the Hesperian/Noachian transition, it would have to be stored in a carbon reservoir on the surface or lost to space. The Mt. Sharp sediments are potentially one of the best places on Mars to investigate these CO2 reservoirs as they are proposed to have formed in the early Hesperian, from an alkaline lake, and record the transition to an aeolian dominated regime near the top of the sequence. The total amount of CO2 in the Gale crater soils and sediments is significant but lower than expected if a thick atmosphere was present at the Hesperian/Noachian boundary. Likewise, the absence of carbonates suggests that CO2- weathering processes similar to those present on Earth were not dominant. Instead it is possible that more exotic CO2 deposition has occurred driven by atmospheric photochemistry and/or degradation of organic carbon.
Niles, P. B.↗
Bioreactor Development for CO2-Based In Situ Resource Utilization Manufacturing
Sustainable long-duration manned missions on both the Moon and Mars will require in situ resource utilization (ISRU). Carbon dioxide (CO2) has great potential as a harvestable resource, making up 95% of the atmosphere on Mars and being produced as respiratory waste in spacecraft and future planetary habitats. Through ISRU, biomanufacturing has the capability to produce a near limitless array of products from local space resources. Here, a CO2-based ISRU recombinant protein producing bioreactor and associated biomanufacturing organisms were designed to produce a highly stable carbonic anhydrase (CA). Candidate organisms were selected by growth characterization on acetate and formic acid, carbon substrates that are synthesized via electrochemical conversion of CO2. To improve growth on the CO2 producing substrate formic acid and for direct integration of ISRU CO2, a synthetic Calvin-Benson-Bassam cycle was designed for use in Escherichia coli. Multiplex genetic modification in E. coli was facilitated by a tailored CRISPR/Cas9 and λ red recombineering two-vector system. For expression of CA, a blue light regulated T7 promoter was employed for dynamic and small molecule free induction. Efficient bioproduction through a fed-batch exponential feeding strategy was determined via mass balance analysis from ISRU substrates to biomass and CA yield. Flux balance analysis was used to model ISRU substrate metabolism and metabolic pathway engineering in candidate organisms under cultivation strategy conditions for both metabolism reconstruction and pathway design optimization. Finally, a small-scale, disposable bag bioreactor for use in the NASA Bioculture System infrastructure was designed to enable CO2-based CA biomanufacturing in reduced-gravity environments.
biomanufacturing↗
Bioreactor Development for CO2-Based In Situ Resource Utilization Manufacturing
Sustainable long-duration manned missions on both the Moon and Mars will require in situ resource utilization (ISRU). Carbon dioxide (CO2) has great potential as a harvestable resource, making up 95% of the atmosphere on Mars and being produced as respiratory waste in spacecraft and future planetary habitats. Through ISRU, biomanufacturing has the capability to produce a near limitless array of products from local space resources, which include pharmaceuticals, bioplastics, chemical feedstocks, and industrial enzymes. Here, a CO2-based ISRU recombinant protein bioreactor and associated biomanufacturing organisms were designed to produce a highly stable carbonic anhydrase (CA). Initial work characterized candidate organisms for growth on acetate and formic acid, carbon substrates that can be synthesized via electrochemical conversion of CO2. To improve growth on the CO2 producing substrate formic acid and for direct integration of ISRU CO2, a synthetic Calvin-Benson-Bassam cycle was designed for use in Cyberlindnera jadinii and Escherichia coli. Genetic modifications in E. coli will be facilitated by a tailored CRISPR/Cas9 and λ red recombineering two-vector system. For expression of CA, a blue light regulated T7 promoter was employed for dynamic and small molecule free induction. Efficient bioproduction through a fed-batch exponential feeding strategy was determined via mass balance calculations from ISRU substrates to biomass and CA yield. Flux balance analysis was used to model ISRU substrate metabolism and metabolic pathway engineering in candidate organisms under cultivation strategy conditions for both metabolism reconstruction and pathway design optimization. Finally, a small-scale, disposable bag bioreactor concept for use in the NASA Bioculture System infrastructure was designed to enable CO2-based CA production in reduced-gravity environments.
Biomanufacturing, Pathway Engineering, Flux Balanc↗
Non-Protein Amino Acids Identified in Carbon-Rich Hayabusa Particles
Amino acid abundances in acid-hydrolyzed hot water extracts of gold foils containing five Category 3 (carbon-rich) Hayabusa particles were studied using liquid chromatography with tandem fluorescence and accurate mass detection. Initial particle analyses using field emission scanning electron microscopy with energy-dispersive X-ray spectrometry indicated that the particles were composed mainly of carbon. Prior to amino acid analysis, infrared and Raman microspectroscopy showed some grains possessed primitive organic carbon. Although trace terrestrial contamination, namely L-protein amino acids, was observed in all Hayabusa extracts, several terrestrially uncommon non-protein amino acids were also identified. Some Hayabusa particles contained racemic (D≈L) mixtures of the non-protein amino acids β-aminoisobutyric acid (β-AIB) and β-amino-n-butyric acid (β-ABA) at low abundances ranging from 0.09 to 0.31 nmol g −1 . Larger abundances of the non-protein amino acid β-alanine (9.2 nmol g −1 , ≈4.5 times greater than background levels) were measured in an extract of three Hayabusa particles. This β-alanine abundance was ≈6 times higher than that measured in an extract of a CM2 Murchison grain processed in parallel. The comparatively high β-alanine abundance is surprising as asteroid Itokawa is similar to amino acid-poor LL ordinary chondrites. Elevated β-alanine abundances and racemic β-AIB and β-ABA in Hayabusa grains suggested these compounds have non-biological and plausibly non-terrestrial origins. These results are the first evidence of plausibly extraterrestrial amino acids in asteroid material from a sample-return mission and demonstrate the capabilities of the analytical protocols used to study asteroid Ryugu and Bennu samples returned by the JAXA Hayabusa2 and NASA OSIRIS-REx missions, respectively.
Eric T. Parker↗