| Nanoscale Deformation and Toughening Mechanisms of Nacre |
31 MAR 2011 |
66 pages |
| Authors:
Xiaodong Li; SOUTH CAROLINA UNIV COLUMBIA OFFICE OF SPONSORED PROGRAMS
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 | We found direct evidence that a single-crystal-like aragonite platelet is essentially assembled with aragonite nanoparticles. The aragonite nanoparticles are readily oriented and assembled into pseudo-single-crystal aragonite platelets via screw dislocation and amorphous aggregation, which are two dominant mediating mechanisms between nanoparticles during biomineralization. The heat treatment burned out the biopolymer in nacre, leaving nanoscale holes at the aragonite platelet boundaries and on the platelet surfaces. By directly probing the biopolymer ... |
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| The Paleoclimate of the Dead Sea Basin from the Last Glacial Maximum to the Holocene |
NOV 2001 |
95 pages |
| Authors:
Thomas K. Swoveland; AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH
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| The purpose of this study was to determine the late glacial paleoclimate of the Southern Levant. A study of delta 13C and delta 18O in carbonates (aragonite) was undertaken from a Lisan Core 3, a laminated core, collected from the Lisan Peninsula in the Dead Sea. Accelerator Mass Spectrometer (AMS) ages demonstrated that the core spanned the period from the Last Glacial Maximum (LGM) to the Holocene (20-12 thousand years ... |
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| Evaluating Zeta Potential and the Calcite/Aragonite Ratio as Potential Success Indicators for Magnetic Water Treatment |
22 MAR 1999 |
61 pages |
| Authors:
Kevin M. Lambert; BRIGHAM YOUNG UNIV PROVO UT DEPT OF CIVIL AND ENVIRONMENTAL ENGINEERING
|
| The potential benefits of anti-scale magnetic treatment (AMT) are notrealized or reliably predicted because the factors measuring performance of magnetic treatment have either not been identified or are poorly defined. This report focuses on examination of certain measurable outcomes influencing the impact of AMT using magnetic treatment devices (MTDs). The outcomes analyzed in this research were: zeta potential of aqueous samples, relative proportion of calcium carbonate (CaCO3) crystal phase and ... |
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| Deep-Sea Corals: A New Oceanic Archive |
FEB 1998 |
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| Authors:
Jess F. Adkins; MASSACHUSETTS INST OF TECH CAMBRIDGE
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 | Deep-sea corals are an extraordinary new archive of deep ocean behavior. The species Desmophyllum cristagalli is a solitary coral composed of uranium rich, density banded aragonite that I have calibrated for several paleoclimate tracers. Using a newly developed ICP-MS age screening method, large numbers of samples can be processed relatively quickly and inexpensively to uncover interesting fossil corals for further analysis. |
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| Shock Propagation in Crustal Rocks: Sandstone, Limestone and Shale |
APR 95 |
56 pages |
| Authors:
Thomas J. Ahrens; William W. Anderson; Yusheng Zhao; CALIFORNIA INST OF TECH PASADENA SEISMOLOGICAL LAB
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| We present shock compression and release data for Coconino Sandstone, Solenhofen and Bedford limestones, and Chambless shale. Urnestone, sandstones, and shale display three separate phases on the Hugoniot curve. For sandstone these are quartz, stishovite, and a dense liquid. The limestone Hugoniot phases are calcite 1 and a dense liquid, with an intervening phase of either calcite 3 or aragonite. For dense liquid SiO2, Po=4.150 Mg/m3 and Kso=313.5 GPa. For ... |
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| Atomic Force Microscopy of the Nacreous Layer in Mollusc Shells |
25 FEB 94 |
34 pages |
| Authors:
S. Manne; C. M. Zaremba; R. Giles; L. Huggins; D. E. Morse; CALIFORNIA UNIV SANTA BARBARA DEPT OF CHEMISTRY
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| We present atomic force microscopy observations of mature nacre, specifically the polygonal aragonite tablets which comprise the mineral portion of nacre, in two types of molluscs, a bivalve (Atrina serrate) and a gastropod (Haliotis rufescens). By imaging in liquids it was possible to dissolve away the nacre layer by layer to reveal both the structure of a single, tablet and its relationship to vertically adjacent tablets. Atrina tablets (inner face) ... |
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| Carbonate Microfabrics Permeability Characteristics of Continental Slope and Deep-Water Carbonates from a Microfabric Perspective |
1994 |
18 pages |
| Authors:
Dawn L. Lavoie; William R. Bryant; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| Permeability, the rate at which fluids move through a porous medium, affects the consolidation and reduction in porosity of a sediment with time and overburden pressure. Most marine clays consist of smectites and illites that are fine-grained and platey. In contrast, carbonate sediments are composed of multishaped, multisized components. In general, clay-rich sediments consolidate to lower porosities and are less permeable that carbonates at given overburden pressures. This difference is ... |
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| Artificial Corrosion of Cu-Alloys. A Contribution to Understanding Microbial and Nonmicrobial Sulfide Corrosion |
92 |
38 pages |
| Authors:
Terri L. Woods; EAST CAROLINA UNIV GREENVILLE NC
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| 90 Cu-10Ni wafers were corroded abiotically in synthetic seawater solutions containing various concentrations of H+, dissolved O2, and dissolved sulfide. The samples were not disturbed during the corrosion process by stirring or monitoring of the solution chemistry. The Eh, pH, and the concentrations of dissolved O2 and sulfide in the initial and final solutions were measured. Upon removal, the corroded wafers were analyzed by SEM, EDX, XPS, and electron microprobe. ... |
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| DN Hard Materials Laser Assisted Formation of Dense Phases |
14 JAN 1991 |
36 pages |
| Authors:
Roy Rustum; PENNSYLVANIA STATE UNIV UNIVERSITY PARK MATERIALS RESEARCH LAB
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| Diamond and other high-pressure phases of carbon were synthesized in air by exposing fine particles of carbon black to carbon dioxide and Nd-YAG laser radiation. The high-pressure phases were separated from the carbon black by selective oxidation and were characterized by electron and x-ray diffraction. Formation of cubic diamond, chaoite, and graphite was confirmed. Exposure of a falling stream of 1 um average size a-quartz particles to a continuous wave ... |
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| Chemistry-Structure-Property Interrelationships for Calcareous Deposits as Stand-Alone Coatings |
07 DEC 89 |
39 pages |
| Authors:
William H. Hartt; Samual W. Smith; FLORIDA ATLANTIC UNIV BOCA RATON CENTER FOR MARINE MATERIALS
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| Experiments have been performed where 1018, A710, A537 and HY80 steel specimens of surface finish corresponding to 120, 320, 600 and 1500 polishing were polarized potentiostatically in seawater at -900 mv (SCE). The resulting calcareous deposits were analyzed with regard to structure, composition and morphology and found to be comprised of a relatively thin inner Magnesium rich layer which formed initially and a subsequent, thicker, outer aragonite precipitate. The effect ... |
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| Physical Effects of Beach Nourishment on Sea Turtle Nesting, Delray Beach, Florida. Environmental Impact Research Program |
OCT 87 |
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| Authors:
David A. Nelson; Karen Mauck; John Fletemeyer; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS ENVIRONMENTAL LAB
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| A large percentage of all sea turtle nests in the United States are located in beaches that have been nourished or renourished. Questions have been raised about how physical changes in the beaches will affect the nesting activities of these sea turtles that use nourished beaches for nesting. Delray Beach had a harder consistency from both previous nourishments and the 1984 renourishment. The cause of the harder consistency is unclear. ... |
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| Measurement of In-Situ Shock Effects in Carbonate Rocks. |
29 FEB 1980 |
33 pages |
| Authors:
J. Vizgirda; T. J. Ahrens; CALIFORNIA INST OF TECH PASADENA
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| Detailed X-ray analyses of core samples taken directly beneath Cactus crater revealed a consistent transition from high to low Mg calcite, thus indicating retention of pre-impact stratigraphy and providing strong evidence for the absence of a fall-back breccia lens thicker than about 1 m. A downward displacement of 4 to 8 m was determined by comparing the level of the high to low Mg transition in cores taken directly beneath ... |
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| Reaction of Calcium Silicates with Carbon Dioxide and Water. |
26 SEP 1979 |
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| Authors:
R. L. Berger ; J. Francis Young; ILLINOIS UNIV AT URBANA-CHAMPAIGN
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| The reaction of five calcium silicates with CO2 water were investigated. The calcium silicates differed in Ca/Si ratio or polymorphic type. Reaction kinetics were dependent on the Ca/Si ratio of the initial calcium silicates. Activation energy for the carbonation reaction ranged from 9.8 kcal/mole for Ca3SiO5 to 22.9 kcal/mole for CaSiO3. The reaction products were calcium carbonate (CaCO3) and a calcium silicate hydrate of variable stoichiometry. The Ca and H2O ... |
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| The Carbonate System in the Western Mediterranean Sea |
20 FEB 1979 |
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| Authors:
Frank J. Millero; John Morse; Chen-Tung Chen; ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE MIAMI FL
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| VARIATION IN THE ELASTIC CONSTANTS OF CALCITE WITH PRESSURE. |
JUN 1967 |
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| Authors:
Dattatraya Purushottam Dandekar; CHICAGO UNIV ILL DEPT OF THE GEOPHYSICAL SCIENCES
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| The values of six elastic constants of single crystal calcite are determined to 6 kb at 25 C by the pulse-echo method. The ambient values of these constants agree fairly well with those obtained by Peselnick and Robie. The values of C-33, and C-66 do not change with pressure to 6 kb. These values are, respectively, 8.53 plus or minus 0.05 and 4.33 plus or minus 0.07 x 10 to ... |
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| RESEARCH ON CHEMISTRY AND PHYSICS OF INORGANIC SYSTEMS UNDER EXTREME HIGH PRESSURE AND TEMPERATURE. |
01 DEC 1965 |
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| Authors:
Peter M. Bell ; William W. Atkinson Jr.; Bobby G. Cahoon ; C. S. Hurlbut Jr; HARVARD COLL CAMBRIDGE MASS PRESIDENT AND FELLOWS
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| Using the tetrahedral press and uniaxial press, experiments were carried out on SiO2, CaCO3, FeS2 and Al2SiO5. The quartz-coesite equilibrium was established at 350C and 23kb. Calcite and aragonite were synthesized from each other. The breakdown of marcasite to pyrite was determined as a function of pressure and temperature. The univariant point of the three polymorphs of Al2SiO5 was determined as 300C (plus or minus 50C) at 8kb (plus or ... |
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| MATRIX-MINERAL INTERACTION IN CALCIFIED TISSUES. |
10 JUN 1964 |
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| Authors:
Otto R. Trautz; NEW YORK UNIV N Y COLL OF DENTISTRY
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| Epitactic overgrowth has been discounted as the factor responsible for the preferred orientation of apatite and other mineral salts in fibrous tissues. The precipitation diagram for the calcium-bicarbonate-phosphate system has been elaborated further to show the range of metastability and the effect of an increase in ionic strength and of elevated bicarbonate concentration on metastability of the solution and on the solubility of the precipitate. Presence of magnesium extends the ... |
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Reports by Keyword(s)
ARAGONITE
