scholarly journals Insights on Structure and Threshold Detection Limits of Stichtite (Magnesium-Chromium Carbonate-Hydroxide) by Fourier Transform Infrared Analysis

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 215
Author(s):  
Erik Melchiorre ◽  
Andy Garcia ◽  
Maryjo Brounce
Keyword(s):  
Detection Limits ◽  
Molecular Water ◽  
Infrared Analysis ◽  
Mine Wastes ◽  
Threshold Detection ◽  
Carbonate Hydroxide ◽  
Ph Conditions ◽  
Ir Detection ◽  
Field And Laboratory Conditions ◽  
Very High

Spectral features for natural stichtite at 1042, 1096, 1360, 1638, and 3482 cm−1 provide insights on mineral structure, with peaks consistent with OH− stretching modes bound to Mg or Cr, CO32− antisymmetric stretches and CO32− bound within the sample and molecular water. These Infrared (IR) data suggest natural stichtite forms at a pH of >12 with increased water and decreased carbonate in the interlayer due to a smaller interlayer distance and unit cell. Higher pH favors lower divalent cation purity and may explain observed ranges of non-end member compositions in stichtite from localities around the world, and across geologic time. This constrains stichtite formation to a range of very high pH conditions and is consistent with active serpentinizing fluid vents and some mine wastes. IR has clear application for the detection and quantification of stichtite under field and laboratory conditions within the detection limits of 5% stichtite within a serpentine host. The size and grade of terrestrial stichtite deposits, and resolution of remote sensing instruments, suggest remote IR detection of stichtite is possible, and remote IR detection for Earth and Mars is discussed.

scholarly journals Degradation of Chlorobenzenes at Nanomolar Concentrations byBurkholderia sp. Strain PS14 in Liquid Cultures and in Soil

1999 ◽  
Vol 65 (6) ◽  
pp. 2547-2552 ◽  
Author(s):  
Peter Rapp ◽  
Kenneth N. Timmis
Keyword(s):  
Incubation Period ◽  
Detection Limits ◽  
Batch Experiments ◽  
Sorptive Capacity ◽  
Residual Concentration ◽  
Soil Microcosms ◽  
Initial Concentration ◽  
High Affinity ◽  
Low Cell Density ◽  
Very High

ABSTRACT The utilization of 1,2,4,5-tetrachloro-, 1,2,4-trichloro-, the three isomeric dichlorobenzenes and fructose as the sole carbon and energy sources at nanomolar concentrations was studied in batch experiments with Burkholderia sp. strain PS14. In liquid culture, all chlorobenzenes were metabolized within 1 h from their initial concentration of 500 nM to below their detection limits of 0.5 nM for 1,2,4,5-tetrachloro- and 1,2,4-trichlorobenzene and 7.5 nM for the three dichlorobenzene isomers, with 63% mineralization of the tetra- and trichloroisomers. Fructose at the same initial concentration was, in contrast, metabolized over a 4-h incubation period down to a residual concentration of approximately 125 nM with 38% mineralization during this time. In soil microcosms, Burkholderia sp. strain PS14 metabolized tetrachlorobenzene present at 64.8 ppb and trichlorobenzene present at 54.4 ppb over a 72-h incubation period to below the detection limits of 0.108 and 0.09 ppb, respectively, with approximately 80% mineralization. A high sorptive capacity ofBurkholderia sp. strain PS14 for 1,2,4,5-tetrachlorobenzene was found at very low cell density. The results demonstrate thatBurkholderia sp. strain PS14 exhibits a very high affinity for chlorobenzenes at nanomolar concentrations.

Phase Relations of the Uranyl Oxide Hydrates and their Relevance to the Disposal of Spent Fuel

1990 ◽  
Vol 212 ◽  
Author(s):  
R. J. Finch ◽  
R. C. Ewing
Keyword(s):  
General Formula ◽  
Phase Relations ◽  
Molecular Water ◽  
Spent Fuel ◽  
Geologic Repository ◽  
Structural Sheet ◽  
Natural Analogues ◽  
Ph Conditions ◽  
Image Position

ABSTRACTUranyl oxide hydrates, formed by the alteration of uraninite, are natural analogues for the long-term corrosion products of spent fuel in a geologic repository under oxidizing conditions. The uranyl oxide hydrates may be represented by the general formula:Pb-bearing hydrates require the addition of a neutral uranyl group into the structural sheet (UO2(OH)2) for each interlayer Pb ion. Distortion of the structure associated with the additional uranyl groups is reduced by replacing two structural hydroxyls with a structural oxygen and a molecular water. The general formula for the Pb-uranyl oxide hydrates is:This hypothesis explains the paragenetic sequences:1) schoepite ➛ billietite ➛ protasite ➛ bauranoite2) schoepite ➛ vandendriesscheite ➛ fourmarierite ➛ masuyite ➛ wölsendorfite3) schoepite ➛ vandendriesscheite ➛ fourmarierite ➛ ± masuyite ➛ sayrite ➛ curite, and indicates that, under relatively high pH conditions, schoepite will not be the long-term solubility-controlling phase for uranium in uranium-rich groundwaters.

Matrix Isolation Microsampling Procedures in Quantitative Fourier Transform Infrared Spectrometry

1979 ◽  
Vol 33 (5) ◽  
pp. 477-480 ◽  
Author(s):  
Doyle M. Hembree ◽  
E. Ray Hinton ◽  
Richard R. Kemmerer ◽  
Gleb Mamantov ◽  
E. L. Wehry
Keyword(s):  
Fourier Transform ◽  
Matrix Isolation ◽  
Gaseous Mixture ◽  
Detection Limits ◽  
Fourier Transform Infrared ◽  
Infrared Spectrometry ◽  
Infrared Analysis ◽  
Fourier Transform Infrared Spectrometry ◽  
Cold Surface ◽  
Qualitative And Quantitative

Techniques for microsampling in infrared spectroscopy by matrix isolation are described. In the matrix isolation of liquid or solid compounds, the sample is vaporized and then diluted with a large excess of a matrix gas; the resulting gaseous mixture is deposited on a cold surface for spectroscopic examination as a solid. Detailed descriptions of the apparatus and procedures employed in the preparation of matrix-isolated samples for qualitative and quantitative analyses by Fourier transform infrared spectrometry are presented. Systems for “microsampling” (detection limits for specific compounds ∼0.5 to 1 μg) and “ultramicrosampling” (detection limits ∼50 to 100 ng) matrix isolation spectroscopy are described. Detection limits and Beer's law behavior for polycyclic aromatic hydrocarbons microsampled by matrix isolation are discussed. The advantages of matrix isolation as a technique for qualitative and quantitative infrared analysis of microsamples are itemized.

Inorganic carbon acquisition by Chlamydomonas acidophila across a pH range

2005 ◽  
Vol 83 (7) ◽  
pp. 872-878 ◽  
Author(s):  
Elly Spijkerman
Keyword(s):  
Growth Rate ◽  
Carbonic Anhydrase ◽  
Inorganic Carbon ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Chlamydomonas Acidophila ◽  
Ph Conditions ◽  
Ph Range ◽  
Very High ◽  
External Ph

Chlamydomonas acidophila Negoro had a higher maximum growth rate upon aeration with 5% CO2 (v/v) than in nonaerated conditions at an external pH above 2. In medium with a pH of 1.0 or 2.0, a decrease in the maximum growth rate was observed upon CO2 aeration in comparison with nonaerated conditions. At both very low and very high external pH conditions, an induction of external carbonic anhydrase was detected; this being more pronounced in CO2-aerated cells than in nonaerated cells. It is therefore suggested that the induction of carbonic anhydrase is part of a stress response in Chlamydomonas acidophila. Comparison of some physiological characteristics of Chlamydomonas acidophila acclimated at pH 2.65 and at pH 6.0, revealed that CO2 aeration increased gross maximum photosynthesis at both pHs, whereas respiration, light acclimation, and photoinhibition were not effected. At pH 2.65, Chlamydomonas acidophila was found to have a carbon-concentrating mechanism under nonaerated conditions, whereas it did not under CO2-aerated conditions at pH 6. The affinity for CO2 use in O2 production was not dependent on CO2 aeration, but it was much lower at pH 6 than it was at pH 2.65. CO2 kinetic characteristics indicate that the photosynthesis of Chlamydomonas acidophila in its natural environment is not limited by inorganic carbon.Key words: Chlamydomonas acidophila, CCM, external carbonic anhydrase, photosynthesis, growth rates, pH stress, CO2.

scholarly journals Defining the envelope for sonic IR: detection limits and damage limits

2003 ◽  
Author(s):  
Wayne O. Miller ◽  
Ian M. Darnell ◽  
Michael W. Burke ◽  
Christopher L. Robbins
Keyword(s):  
Detection Limits ◽  
Ir Detection ◽  
Sonic Ir

Preparation and Performance Research of Polyimide Modified Nylon Resin

2011 ◽  
Vol 236-238 ◽  
pp. 548-551
Author(s):  
Hong Kai Zhao ◽  
Li Guang Xiao ◽  
Xiao Jing Zhang
Keyword(s):  
Bisphenol A ◽  
High Performance ◽  
Water Resistance ◽  
Hot Spot ◽  
Microscopic Analysis ◽  
Infrared Analysis ◽  
Lamellar Crystals ◽  
And Performance ◽  
Performance Research ◽  
Very High

High performance trend of plastics has become a hot spot of current research. Select bisphenol A dianhydride and bisphenol A diamine with excellent water resistance as the reactant monomers to obtain anhydride-terminated polyimide with very high molecular weight by two-step polymerization, graft the active radicals of acyl caprolactam using the activity of anhydride and obtain PI modified nylon resin by polymerization. It is proved that the reaction in each above step is successful through infrared analysis. Through microscopic analysis, the molecules of polyimide does not enter crystallization phase of nylon resin, but forms compact lamellar crystals existing in nylon matrix.

The vegetation of metalliferous and non-metalliferous grasslands in two former mine regions in Central Slovakia

Biologia ◽  
2006 ◽  
Vol 61 (4) ◽  
Author(s):  
Viera Banásová ◽  
Othmar Horak ◽  
Milada Čiamporová ◽  
Miriam Nadubinská ◽  
Irene Lichtscheidl
Keyword(s):  
Lichen Species ◽  
Uniform Structure ◽  
Mine Wastes ◽  
Silene Dioica ◽  
Agrostis Capillaris ◽  
Cu Content ◽  
Arabidopsis Arenosa ◽  
Avenella Flexuosa ◽  
Mining Regions ◽  
Very High

AbstractWe investigated the composition of the vegetation in two former mining regions in Central Slovakia: Banská Štiavnica with predominant Pb-Zn contamination and Staré Hory with a very high Cu content in the soil. Old heaps rich in heavy metals are covered with specific vegetation. On the Cu-rich spoil heaps, species-poor plant communities with prevailing Agrostis stolonifera, Avenella flexuosa, Acetosella vulgaris, Arabidopsis arenosa, Silene dioica, and S. vulgaris occur. Species such as Agrostis capillaris, Acetosella vulgaris, Arabidopsis arenosa, and Thlaspi caerulescens appear frequently on Pb-Zn mine wastes. Several differences in the vegetation structure were detected between the Pb-Zn and Cu mine heaps; higher amounts of vascular plants and fewer lichen species covered the Pb-Zn mine heaps. For the Cu mine heaps, on the contrary a small number of vascular species but a high number and coverage of lichen species, especially Ceratodon purpureus and Cladonia arbuscula subsp. mitis were typical. The non-metalliferous meadows in the vicinity of the mines showed uniform structure but a higher species diversity.

Enhancing IR Detection Limits for Trace Polar Organics in Aqueous Solutions with Surface-Modified Sol-Gel-Coated ATR Sensors

1999 ◽  
Vol 53 (4) ◽  
pp. 381-389 ◽  
Author(s):  
Ling Han ◽  
Thomas M. Niemczyk ◽  
David M. Haaland ◽  
Gabriel P. Lopez
Keyword(s):  
Aqueous Solutions ◽  
Sol Gel ◽  
Detection Limits ◽  
Ir Detection ◽  
Surface Modified ◽  
Polar Organics

Simple Near-Infrared Spectrometric Sorption-Based Vapor Sensor

1995 ◽  
Vol 49 (9) ◽  
pp. 1261-1267 ◽  
Author(s):  
Andrew Fong ◽  
Gary M. Hieftje
Keyword(s):  
Fiber Optics ◽  
Silica Gel ◽  
Near Infrared ◽  
Detection Limits ◽  
Polar Compounds ◽  
Quantitative Information ◽  
Absorption Bands ◽  
Near Ir ◽  
Vibrational Overtone ◽  
Ir Detection

A new class of near-IR sensors has been devised which relies on spectroscopic near-IR detection of analytes sorbed on a preconcentrating layer. The new sensors furnish both qualitative and quantitative information by detection of molecular vibrational overtone and combination absorption bands and by measurement of changes in the scattering of the silica-gel medium. A silica-gel thin-layer chromatography (TLC) plate was used as the adsorbent medium. This method is responsive to vapors ranging from water to carbon tetrachloride. Ethyl- and octylderivatized TLC plates were also tested and generally exhibited a weaker response and different spectral features than the original plate. The optical nature of these sensors opens up the possibility of remote analysis by coupling the technique with fiber optics and/or near-IR light-emitting diodes and lasers. Detection limits ranged from 4.1 to 210 ppm by volume. Polar compounds able to hydrogen bond to the surface exhibited lower detection limits than nonpolar compounds.

Very High Resolution Analysis of the Dynamics of a Coronal Plasmoid

1994 ◽  
Vol 144 ◽  
pp. 593-596
Author(s):  
O. Bouchard ◽  
S. Koutchmy ◽  
L. November ◽  
J.-C. Vial ◽  
J. B. Zirker
Keyword(s):  
High Resolution ◽  
Solar Eclipse ◽  
Total Solar Eclipse ◽  
Field Of View ◽  
Small Field ◽  
High Resolution Analysis ◽  
Ccd Observations ◽  
Resolution Analysis ◽  
Very High ◽  
Small Field Of View

AbstractWe present the results of the analysis of a movie taken over a small field of view in the intermediate corona at a spatial resolution of 0.5“, a temporal resolution of 1 s and a spectral passband of 7 nm. These CCD observations were made at the prime focus of the 3.6 m aperture CFHT telescope during the 1991 total solar eclipse.

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