DOCSLIB.ORG

No Compelling Evidence for Clathrate Hydrate Formation Under Interstellar Medium Conditions LETTER Over Laboratory Time Scales Mathieu Choukrouna,1, Tuan H

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
No Compelling Evidence for Clathrate Hydrate Formation Under Interstellar Medium Conditions LETTER Over Laboratory Time Scales Mathieu Choukrouna,1, Tuan H LETTER No compelling evidence for clathrate hydrate formation under interstellar medium conditions LETTER over laboratory time scales Mathieu Choukrouna,1, Tuan H. Vua, and Edith C. Fayollea − In PNAS, Ghosh et al. (1) report their experimental shows a shift of −7cm1), whereas the computed −1 observations of methane and CO2 clathrate formation shift is −86.0 cm . −1 at conditions similar to the interstellar medium (ISM), The emergence of a 2,346 cm CO2 peak is inter- − namely 10 to 30 K and 10 10 mbar. The authors con- preted as due to clathrate formation by analogy to an ducted time-dependent reflection–absorption infrared earlier study (4). However, in that work, the chemical spectroscopy (RAIRS) of vapor-deposited H2O–CH4 system also contained CH3OH, whose presence ap- and H2O–CO2 mixtures and interpreted new blue pears necessary for CO2 clathrates to form after slow and red shifted peaks from those of trapped CH4 and heating to 120 K. In addition, CO2 clathrates grown CO2 in amorphous ice, respectively, as indicative of epitaxially on other clathrates (5) or formed under clathrate formation. In this letter, we point out poten- higher pressure/temperature conditions (6) have a char- tial pitfalls and caution against the implications drawn acteristic IR signature with double peaks consistently 12 13 for the ISM. observed in the ν3 regions of both CO2 and CO2, In the case of the H2O–CO2 system, Ghosh et al. unlike the signatures observed in figure 2 and figure (1) attribute the observed red shift in the infrared S5 of ref. 1. Furthermore, RAIRS studies of layered (IR) spectra to hydrogen bonding between CO2 and mixed H2O–CO2 ices (7, 8) reported a peak around − and the water cage. This statement not only 2,346 cm 1, which was interpreted in these studies as goes against the common knowledge of CO2’s CO2 interacting with or being trapped within amor- lack of affinity for hydrogen bonding, but also phous H2O [albeit not as forming a clathrate as contradicts the calculated structure in figure 2 of inferred by Ghosh et al. (1)] ref. 1, which clearly shows that there is no available For the H2O–CH4 system, the calculated blue shift 12 12 hydrogen atom in the 5 cage for the CO2 guest for methane in the 5 cage (1) is inconsistent with to form hydrogen bonds with. Any hydrogen bond- previous experimental studies showing that enclathrated ing with the skeleton would greatly distort the methane exhibits a red shift (9, 10). Predicted red cage structure, as has been suggested for NH3- shifts for other cage types and for CO2 presented bearing clathrates (2). Furthermore, the O–H stretch- in the present study (1) are also consistent with this ingbandinfigureS4ofref.1ischaracteristicof general behavior. amorphous ice (3), while clathrate hydrates are In summary, we find that the experimental data crystalline compounds. and theoretical computations in Ghosh et al. (1) do not Ghosh et al. (1) argue that the close match be- support the interpretation of clathrate hydrate forma- tween experimentally observed shifts and computed tion. The community should be cautioned against shifts indicates formation of a clathrate 512 cage. How- interpreting this article as definitive evidence that − ever, table S1 of ref. 1 claims a shift of −36.0 cm 1 for clathrates can be formed in the ISM within short (ap- the CO2 antisymmetric stretch (although figure 2 ref. 1 proximately days) laboratory time scales. 1 J. Ghosh et al., Clathrate hydrates in interstellar environment. Proc. Natl. Acad. Sci. U.S.A. 116, 1526–1531 (2019). 2 K. Shin, R. Kumar, K. A. Udachin, S. Alavi, J. A. Ripmeester, Ammonia clathrate hydrates as new solid phases for Titan, Enceladus, and other planetary systems. Proc. Natl. Acad. Sci. U.S.A. 109, 14785–14790 (2012). 3 W. Hagen, A. Tielens, J. Greenberg, The infrared spectra of amorphous solid water and ice Ic between 10 and 140 K. Chem. Phys. 56, 367–379 (1981). aJet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 Author contributions: M.C., T.H.V., and E.C.F. wrote the paper. The authors declare no conflict of interest. Published under the PNAS license. 1To whom correspondence may be addressed. Email: [email protected]. Published online July 3, 2019. www.pnas.org/cgi/doi/10.1073/pnas.1902381116 PNAS | July 16, 2019 | vol. 116 | no. 29 | 14407–14408 Downloaded by guest on September 23, 2021 4 D. Blake, L. Allamandola, S. Sandford, D. Hudgins, F. Freund, Clathrate hydrate formation in amorphous cometary ice analogs in vacuo. Science 254,548–551 (1991). 5 F. Fleyfel, J. P. Devlin, Carbon dioxide clathrate hydrate epitaxial growth: Spectroscopic evidence for formation of the simple type-II carbon dioxide hydrate. J. Phys. Chem. 95, 3811–3815 (1991). 6 E. Dartois, B. Schmitt, Carbon dioxide clathrate hydrate FTIR spectrum: Near infrared combination modes for astrophysical remote detection. Astron. Astrophys. 504, 869–873 (2009). 7 B. Mate ´ et al., Ices of CO2/H2O mixtures. Reflection-absorption IR spectroscopy and theoretical calculations. J. Phys. Chem. A 112, 457–465 (2008). 8 J. L. Edridge et al., Surface science investigations of the role of CO2 in astrophysical ices. Phil. Trans. R. Soc. A 2013, 20110578 (1994). 9 E. Dartois, D. Deboffle, Methane clathrate hydrate FTIR spectrum: Implications for its cometary and planetary detection. Astron. Astrophys. 490, L19–L22 (2008). 10 S. Subramanian, E. Sloan, Jr, Molecular measurements of methane hydrate formation. Fluid Phase Equilib. 158, 813–820 (1999). 14408 | www.pnas.org/cgi/doi/10.1073/pnas.1902381116 Choukroun et al. Downloaded by guest on September 23, 2021.
Load more

Recommended publications
  • Bioinspired Intrinsic Control of Freeze Cast Composites: Harnessing Hydrophobic Hydration and Clathrate Hydrates
    Acta Materialia 114 (2016) 67e79 Contents lists available at ScienceDirect Acta Materialia journal homepage: www.elsevier.com/locate/actamat Full length article Bioinspired intrinsic control of freeze cast composites: Harnessing hydrophobic hydration and clathrate hydrates * Steven E. Naleway a, , Christopher F. Yu b, Rachel L. Hsiong b, Arijit Sengupta e, Peter M. Iovine e, John A. Hildebrand c, Marc A. Meyers a, b, d, Joanna McKittrick a, b a Materials Science and Engineering Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA b Department of Mechanical and Aerospace Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA c Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA d Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA e Department of Chemistry and Biochemistry, University of San Diego, San Diego, CA 92110, USA article info abstract Article history: Bioinspired ZrO2-epoxy, two-phase composite materials were fabricated by the freeze casting fabrication Received 7 January 2016 technique followed by polymer infiltration. These materials were intrinsically controlled by adding Received in revised form varying concentrations of the monofunctional alcohols ethanol (EtOH), n-propanol (n-PrOH) and n- 9 May 2016 butanol (n-BuOH). The microstructures of freeze cast scaffolds created with these alcohol additives Accepted 10 May 2016 demonstrated maximum pore areas (peak Ap) at concentrations of 10, 5e7 and 3 vol% for EtOH, n-PrOH and n-BuOH respectively. Differential scanning calorimetry analyses of binary mixtures of these additives and water suggested only n-PrOH was capable of developing clathrate hydrates.
    [Show full text]
  • Ice Ic” Werner F
    Extent and relevance of stacking disorder in “ice Ic” Werner F. Kuhsa,1, Christian Sippela,b, Andrzej Falentya, and Thomas C. Hansenb aGeoZentrumGöttingen Abteilung Kristallographie (GZG Abt. Kristallographie), Universität Göttingen, 37077 Göttingen, Germany; and bInstitut Laue-Langevin, 38000 Grenoble, France Edited by Russell J. Hemley, Carnegie Institution of Washington, Washington, DC, and approved November 15, 2012 (received for review June 16, 2012) “ ” “ ” A solid water phase commonly known as cubic ice or ice Ic is perfectly cubic ice Ic, as manifested in the diffraction pattern, in frequently encountered in various transitions between the solid, terms of stacking faults. Other authors took up the idea and liquid, and gaseous phases of the water substance. It may form, attempted to quantify the stacking disorder (7, 8). The most e.g., by water freezing or vapor deposition in the Earth’s atmo- general approach to stacking disorder so far has been proposed by sphere or in extraterrestrial environments, and plays a central role Hansen et al. (9, 10), who defined hexagonal (H) and cubic in various cryopreservation techniques; its formation is observed stacking (K) and considered interactions beyond next-nearest over a wide temperature range from about 120 K up to the melt- H-orK sequences. We shall discuss which interaction range ing point of ice. There was multiple and compelling evidence in the needs to be considered for a proper description of the various past that this phase is not truly cubic but composed of disordered forms of “ice Ic” encountered. cubic and hexagonal stacking sequences. The complexity of the König identified what he called cubic ice 70 y ago (11) by stacking disorder, however, appears to have been largely over- condensing water vapor to a cold support in the electron mi- looked in most of the literature.
    [Show full text]
  • Indiana Glaciers.PM6
    How the Ice Age Shaped Indiana Jerry Wilson Published by Wilstar Media, www.wilstar.com Indianapolis, Indiana 1 Previiously published as The Topography of Indiana: Ice Age Legacy, © 1988 by Jerry Wilson. Second Edition Copyright © 2008 by Jerry Wilson ALL RIGHTS RESERVED 2 For Aaron and Shana and In Memory of Donna 3 Introduction During the time that I have been a science teacher I have tried to enlist in my students the desire to understand and the ability to reason. Logical reasoning is the surest way to overcome the unknown. The best aid to reasoning effectively is having the knowledge and an understanding of the things that have previ- ously been determined or discovered by others. Having an understanding of the reasons things are the way they are and how they got that way can help an individual to utilize his or her resources more effectively. I want my students to realize that changes that have taken place on the earth in the past have had an effect on them. Why are some towns in Indiana subject to flooding, whereas others are not? Why are cemeteries built on old beach fronts in Northwest Indiana? Why would it be easier to dig a basement in Valparaiso than in Bloomington? These things are a direct result of the glaciers that advanced southward over Indiana during the last Ice Age. The history of the land upon which we live is fascinating. Why are there large granite boulders nested in some of the fields of northern Indiana since Indiana has no granite bedrock? They are known as glacial erratics, or dropstones, and were formed in Canada or the upper Midwest hundreds of millions of years ago.
    [Show full text]
  • Genesis and Geographical Aspects of Glaciers - Vladimir M
    HYDROLOGICAL CYCLE – Vol. IV - Genesis and Geographical Aspects of Glaciers - Vladimir M. Kotlyakov GENESIS AND GEOGRAPHICAL ASPECTS OF GLACIERS Vladimir M. Kotlyakov Institute of Geography, Russian Academy of Sciences, Moscow, Russia Keywords: Chionosphere, cryosphere, equilibrium line, firn line, glacial climate, glacier, glacierization, glaciosphere, ice, seasonal snow line, snow line, snow-patch Contents 1. Introduction 2. Properties of natural ice 3. Cryosphere, glaciosphere, chionosphere 4. Snow-patches and glaciers 5. Basic boundary levels of snow and ice 6. Measures of glacierization 7. Occurrence of glaciers 8. Present-day glacierization of the Arctic Glossary Bibliography Biographical Sketch Summary There exist ten crystal variants of ice and one amorphous form in Nature, however only one form ice-1 is distributed on the Earth. Ten other ice variants steadily exist only under a certain combinations of pressure, specific volume and temperature of medium, and those are not typical for our planet. The ice density is less than that of water by 9%, and owing to this water reservoirs are never totally frozen., Thus life is sustained in them during the winter time. As a rule, ice is much cleaner than water, and specific gas-ice compounds called as crystalline hydrates are found in ice. Among the different spheres surrounding our globe there are cryosphere (sphere of the cold), glaciosphere (sphere of snow and ice) and chionosphere (that part of the troposphere where the annual amount of solid precipitation exceeds their losses). The chionosphere envelopes the Earth with a shell 3 to 5 km in thickness. In the present epoch, snow and ice cover 14.2% of the planet’s surface and more than half of the land surface.
    [Show full text]
  • Case Fil Copy
    NASA TECHNICAL NASA TM X-3511 MEMORANDUM CO >< CASE FIL COPY REPORTS OF PLANETARY GEOLOGY PROGRAM, 1976-1977 Compiled by Raymond Arvidson and Russell Wahmann Office of Space Science NASA Headquarters NATIONAL AERONAUTICS AND SPACE ADMINISTRATION • WASHINGTON, D. C. • MAY 1977 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. TMX3511 4. Title and Subtitle 5. Report Date May 1977 6. Performing Organization Code REPORTS OF PLANETARY GEOLOGY PROGRAM, 1976-1977 SL 7. Author(s) 8. Performing Organization Report No. Compiled by Raymond Arvidson and Russell Wahmann 10. Work Unit No. 9. Performing Organization Name and Address Office of Space Science 11. Contract or Grant No. Lunar and Planetary Programs Planetary Geology Program 13. Type of Report and Period Covered 12. Sponsoring Agency Name and Address Technical Memorandum National Aeronautics and Space Administration 14. Sponsoring Agency Code Washington, D.C. 20546 15. Supplementary Notes 16. Abstract A compilation of abstracts of reports which summarizes work conducted by Principal Investigators. Full reports of these abstracts were presented to the annual meeting of Planetary Geology Principal Investigators and their associates at Washington University, St. Louis, Missouri, May 23-26, 1977. 17. Key Words (Suggested by Author(s)) 18. Distribution Statement Planetary geology Solar system evolution Unclassified—Unlimited Planetary geological mapping Instrument development 19. Security Qassif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price* Unclassified Unclassified 294 $9.25 * For sale by the National Technical Information Service, Springfield, Virginia 22161 FOREWORD This is a compilation of abstracts of reports from Principal Investigators of NASA's Office of Space Science, Division of Lunar and Planetary Programs Planetary Geology Program.
    [Show full text]
  • Searching for Crystal-Ice Domains in Amorphous Ices
    PHYSICAL REVIEW MATERIALS 2, 075601 (2018) Searching for crystal-ice domains in amorphous ices Fausto Martelli,1,2,* Nicolas Giovambattista,3,4 Salvatore Torquato,2 and Roberto Car2 1IBM Research, Hartree Centre, Daresbury WA4 4AD, United Kingdom 2Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA 3Department of Physics, Brooklyn College of the City University of New York, Brooklyn, New York 11210, USA 4The Graduate Center of the City University of New York, New York, New York 10016, USA (Received 7 May 2018; published 2 July 2018) Weemploy classical molecular dynamics simulations to investigate the molecular-level structure of water during the isothermal compression of hexagonal ice (Ih) and low-density amorphous (LDA) ice at low temperatures. In both cases, the system transforms to high-density amorphous ice (HDA) via a first-order-like phase transition. We employ a sensitive local order metric (LOM) [F. Martelli et al., Phys. Rev. B 97, 064105 (2018)] that can discriminate among different crystalline and noncrystalline ice structures and is based on the positions of the oxygen atoms in the first- and/or second-hydration shell. Our results confirm that LDA and HDA are indeed amorphous, i.e., they lack polydispersed ice domains. Interestingly, HDA contains a small number of domains that are reminiscent of the unit cell of ice IV,although the hydrogen-bond network (HBN) of these domains differs from the HBN of ice IV. The presence of ice-IV-like domains provides some support to the hypothesis that HDA could be the result of a detour on the HBN rearrangement along the Ih-to-ice-IV pressure-induced transformation.
    [Show full text]
  • 11Th International Conference on the Physics and Chemistry of Ice, PCI
    11th International Conference on the Physics and Chemistry of Ice (PCI-2006) Bremerhaven, Germany, 23-28 July 2006 Abstracts _______________________________________________ Edited by Frank Wilhelms and Werner F. Kuhs Ber. Polarforsch. Meeresforsch. 549 (2007) ISSN 1618-3193 Frank Wilhelms, Alfred-Wegener-Institut für Polar- und Meeresforschung, Columbusstrasse, D-27568 Bremerhaven, Germany Werner F. Kuhs, Universität Göttingen, GZG, Abt. Kristallographie Goldschmidtstr. 1, D-37077 Göttingen, Germany Preface The 11th International Conference on the Physics and Chemistry of Ice (PCI- 2006) took place in Bremerhaven, Germany, 23-28 July 2006. It was jointly organized by the University of Göttingen and the Alfred-Wegener-Institute (AWI), the main German institution for polar research. The attendance was higher than ever with 157 scientists from 20 nations highlighting the ever increasing interest in the various frozen forms of water. As the preceding conferences PCI-2006 was organized under the auspices of an International Scientific Committee. This committee was led for many years by John W. Glen and is chaired since 2002 by Stephen H. Kirby. Professor John W. Glen was honoured during PCI-2006 for his seminal contributions to the field of ice physics and his four decades of dedicated leadership of the International Conferences on the Physics and Chemistry of Ice. The members of the International Scientific Committee preparing PCI-2006 were J.Paul Devlin, John W. Glen, Takeo Hondoh, Stephen H. Kirby, Werner F. Kuhs, Norikazu Maeno, Victor F. Petrenko, Patricia L.M. Plummer, and John S. Tse; the final program was the responsibility of Werner F. Kuhs. The oral presentations were given in the premises of the Deutsches Schiffahrtsmuseum (DSM) a few meters away from the Alfred-Wegener-Institute.
    [Show full text]
  • Temperature- and Pressure-Dependent Structural Transformation of Methane Hydrates in Salt Environments
    PUBLICATIONS Geophysical Research Letters RESEARCH LETTER Temperature- and pressure-dependent structural 10.1002/2016GL072277 transformation of methane hydrates Key Points: in salt environments • Under a low-pressure condition, the methane hydrate is decomposed Donghoon Shin1 , Minjun Cha2 , Youjeong Yang3, Seunghyun Choi1, Yesol Woo1 , through a rapid sublimation of water 4 5 6 6 7,8,9 1,3 from the surface of hydrate crystals Jong-Won Lee , Docheon Ahn , Junhyuck Im , Yongjae Lee , Oc Hee Han , and Ji-Ho Yoon • The hydrated salt of NaCl · 2H2O 1 undergoes a phase transition into a Department of Energy and Resources Engineering, Korea Maritime and Ocean University, Busan, South Korea, crystal growth of crystalline NaCl via 2Department of Energy and Resources Engineering, Kangwon National University, Chuncheon, South Korea, 3Department the migration of salt ions of Convergence Study on the Ocean Science and Technology, Ocean Science and Technology School, Korea Maritime and • The methane hydrate is fully Ocean University, Busan, South Korea, 4Department of Environmental Engineering, Kongju National University, Chungnam, decomposed in brine solutions at 5 6 temperatures above 252 K, the South Korea, Beamline Department, Pohang Accelerator Laboratory, Pohang, South Korea, Department of Earth System 7 eutectic point of NaCl · 2H2O Sciences, Yonsei University, Seoul, South Korea, Western Seoul Center, Korea Basic Science Institute, Seoul, South Korea, 8Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon, South Korea, 9Department of Chemistry and Nano-Science, College of Natural Sciences, Ewha Womans University, Seoul, South Korea Supporting Information: • Supporting Information S1 Abstract Understanding the stability of volatile species and their compounds under various surface and Correspondence to: J.-H.
    [Show full text]
  • 1 2.6 Physical Chemistry and Thermal Evolution of Ices at Ganymede 1 C
    1 1 2.6 Physical Chemistry and Thermal Evolution of Ices at Ganymede 2 C. Ahrens, NASA Goddard Space Flight Center, Greenbelt, MD; [email protected] 3 A. Solomonidou, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA; & LEISA 4 – Observatoire de Paris, CNRS, UPMC Univ., Paris 06, Univ. Paris-Diderot, Meudon, France; 5 [email protected] 6 K. Stephan, Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany; 7 [email protected] 8 K. Kalousova, Charles University, Faculty of Mathematics and Physics, Department of Geophysics, 9 Prague, Czech Republic; [email protected] 10 N. Ligier, Institut d’Astrophysique Spatiale, Université Paris-Saclay, Orsay, France; 11 [email protected] 12 T. McCord, Bear Fight Institute, Winthrop, WA; [email protected] 13 C. Hibbitts, Applied Physics Laboratory, Johns Hopkins University, Laurel, MD; 14 [email protected] 15 16 Abstract 17 18 Ganymede’s surface is composed mostly of water ice and other icy materials in addition to minor non-ice 19 components. The formation and evolution of Ganymede’s landforms highly depend on the nature of the 20 icy materials as they present various thermal and rheological behaviors. This chapter reviews the 21 currently known thermodynamic parameters of the ice phases and hydrates reported on Ganymede, which 22 seem to affect the evolution of the surface, using mainly results from the Voyager and Galileo missions. 23 24 Keywords: Ganymede; Ices; Ices, Mechanical Properties; Experimental techniques; Geological 25 processes 26 27 1 Introduction 28 29 Icy bodies of the outer solar system, including satellites of the gas giants, harbor surface ices made of 30 volatile molecules, clathrates, and complex molecules like hydrocarbons.
    [Show full text]
  • Ethane Clathrate Hydrate Infrared Signatures for Solar System Remote Sensing E Dartois, F Langlet
    Ethane clathrate hydrate infrared signatures for solar system remote sensing E Dartois, F Langlet To cite this version: E Dartois, F Langlet. Ethane clathrate hydrate infrared signatures for solar system remote sensing. Icarus, Elsevier, 2021. hal-03159998 HAL Id: hal-03159998 https://hal.archives-ouvertes.fr/hal-03159998 Submitted on 4 Mar 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Ethane clathrate hydrate infrared signatures for solar system remote sensing. E. Dartois1, F. Langlet2, 1 Institut des Sciences Moléculaires d’Orsay, CNRS, Université Paris-Saclay, Bât 520, Rue André Rivière, 91405 Orsay, France e-mail: [email protected] 2 Institut d’Astrophysique Spatiale (IAS), UMR8617, CNRS, Université Paris-Saclay, Bât. 121, 91405 Orsay, France keywords: Planetary ices, IR spectroscopy, Clathrate hydrate, Ethane, Remote sensing To appear in Icarus Abstract their retention time scales in solar system bodies, and also mod- ify their release conditions. b=The hydrate term is sometimes Hydrocarbons such as methane and ethane are present in many used as a semantic shortcut to designate clathrate hydrates but solar system objects, including comets, moons and planets. The must not be confused neither with hydrates nor with ice mixtures interaction of these hydrocarbons with water ice at low temper- where a molecule is interacting with water ice and not necessar- atures could lead to the formation of inclusion compounds, such ily mediated via an ordered crystalline cage.
    [Show full text]
  • Structural and Kinetic Studies of Structure I Gas Hydrates Via Low Temperature X-Ray Diffraction and High Resolution Neutron Diffraction
    University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 5-2013 Structural and Kinetic Studies of Structure I Gas Hydrates via Low Temperature X-Ray Diffraction and High Resolution Neutron Diffraction Susan Michelle Everett [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Other Materials Science and Engineering Commons Recommended Citation Everett, Susan Michelle, "Structural and Kinetic Studies of Structure I Gas Hydrates via Low Temperature X-Ray Diffraction and High Resolution Neutron Diffraction. " PhD diss., University of Tennessee, 2013. https://trace.tennessee.edu/utk_graddiss/1718 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Susan Michelle Everett entitled "Structural and Kinetic Studies of Structure I Gas Hydrates via Low Temperature X-Ray Diffraction and High Resolution Neutron Diffraction." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Doctor of Philosophy, with a major in Materials Science and Engineering. Claudia
    [Show full text]
  • Ice Molecular Model Kit © Copyright 2015 Ryler Enterprises, Inc
    Super Models Ice Molecular Model Kit © Copyright 2015 Ryler Enterprises, Inc. Recommended for ages 10-adult ! Caution: Atom centers and vinyl tubing are a choking hazard. Do not eat or chew model parts. Kit Contents: 50 red 4-peg oxygen atom centers (2 spares) 100 white hydrogen 2-peg atom centers (2 spares) 74 clear, .87”hydrogen bonds (2 spares) 100 white, .87” covalent bonds (2 spares) Related Kits Available: Chemistry of Water Phone: 806-438-6865 E-mail: [email protected] Website: www.rylerenterprises.com Address: 5701 1st Street, Lubbock, TX 79416 The contents of this instruction manual may be reprinted for personal use only. Any and all of the material in this PDF is the sole property of Ryler Enterprises, Inc. Permission to reprint any or all of the contents of this manual for resale must be submitted to Ryler Enterprises, Inc. General Information Ice, of course, ordinarily refers to water in the solid phase. In the terminology of astronomy, an ice can be the solid form of any element or compound which is usually a liquid or gas. This kit is designed to investigate the structure of ice formed by water. Fig. 1 Two water molecules bonded by a hydrogen bond. Water ice is very common throughout the universe. According to NASA, within our solar system ice is The symbol δ means partial, so when a plus sign is found in comets, asteroids, and several moons of added, the combination means partial positive the outer planets, and it has been located in charge. The opposite obtains when a negative sign interstellar space as well.
    [Show full text]