scholarly journals Evolution with depth from detrital to authigenic smectites in sediments from AND-2A drill core (McMurdo Sound, Antarctica)

Clay Minerals ◽  
2012 ◽  
Vol 47 (4) ◽  
pp. 481-498 ◽  
Author(s):  
F. Iacoviello ◽  
G. Giorgetti ◽  
F. Nieto ◽  
I. T. Memmi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Clay Minerals ◽  
Clay Fraction ◽  
Drill Core ◽  
Mcmurdo Sound ◽  
Volcanic Material ◽  
The Core ◽  
Diagenetic Processes ◽  
Scanning Electron

AbstractWe have examined the nature and origin of smectites in glaciomarine sediments of the AND-2A drill core (McMurdo Sound, Antarctica) by means of X-ray diffraction (XRD) analyses on the clay fraction, field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM) observations and SEM-EDS microanalyses on smectite particles. Relying on the smectite variation throughout the drill core it was possible to split the sequence into three units. Smectites throughout the core are either detrital or authigenic. Detrital smectites are close to montmorillonite-beidellite in composition while newly-formed smectites frequently have higher Fe-Mg contents and intermediate compositions between the saponite and nontronite field, with lower amounts in the montmorillonite-beidellite field. In the upper sedimentary sections (Unit I, and Unit II, 36-440 mbsf, 0.7-16.5 Ma) smectites are interpreted to be predominantly detrital, whereas in the lower portion of the core (Unit III, 440-1123.20 mbsf, 16.5-20.2 Ma) authigenic smectites are the most common feature. The predominance of mica, the abundance of chlorite, and the nature of smectites in the upper units indicate physical weathering under cold and dry climate, and a dominant provenance for the clay minerals from the Transantarctic Mountains. Smectites in the lower unit are considered mostly authigenic and they are most likely to be the result of early diagenetic processes, being formed from the alteration of volcanic material (glass, pyroxenes and feldspars) and/or through precipitation from fluids of a possible hydrothermal origin. Our survey attests to the importance of discriminating between a detrital and authigenic nature of smectites as the occurrence of authigenic clay minerals in ancient sedimentary successions might lead to incorrect palaeoclimatic interpretations, since they can be affected by diagenetic processes, thus obliterating the climatic signal.

Environmental Scanning Electron Microscopy Technique to Identify Asbestos Phases Inside Ferruginous Bodies

2013 ◽  
Vol 19 (2) ◽  
pp. 420-424 ◽  
Author(s):  
Alessandro Croce ◽  
Maya Musa ◽  
Mario Allegrina ◽  
Paolo Trivero ◽  
Caterina Rinaudo
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Elements ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Thin Sections ◽  
The Core ◽  
Microscopy Technique ◽  
Ferruginous Bodies ◽  
Scanning Electron

AbstractFerruginous bodies observed in lungs of patients affected by mesothelioma, asbestosis, and pulmonary carcinoma are important to relate the illness to exposure, environmental or occupational, to asbestos. Identification of the inorganic phase constituting the core of the ferruginous bodies, formed around asbestos but also around phases different from asbestos, is essential for legal purposes. Environmental scanning electron microscopy/energy dispersive spectroscopy was used to identify the fibrous mineral phase in the core of ferruginous bodies observed directly in thin sections of tissue, without digestion of the biological matrix. Spectra were taken with sequential analyses along a line crossing the core of the ferruginous bodies. By comparing the spectra taken near to and far from the core, the chemical elements that make up the core could be identified.

Preparation of Polyaniline @ Polypyrrole Conductive Composite via In Situ Polymerization

2013 ◽  
Vol 562-565 ◽  
pp. 1137-1142
Author(s):  
Hui Xia Feng ◽  
Bing Wang ◽  
Lin Tan ◽  
Na Li Chen
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
In Situ Polymerization ◽  
Conductive Composite ◽  
The Core ◽  
Novel Method ◽  
Scanning Electron

We prepared the polyaniline@polypyrrole (PAn@PPy) conductive composite by a novel method. The struction like Pre-prepared PAn as the core and PPy as the shell for the composite has been prepared by in-situ polymerization. The PAn@PPy conductive composite presents an electrical conductivity of 12.5 S/cm, which is much higher than pure PAn. The synthesized polymer composites are characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Thermogravimetric analysis (TG). The results indicated that PPy successfully grafted on PAn and the heat resistance of nanocomposite is remarkably increased.

Compositional and architectural variation in urinary calculi from nucleus to periphery: an integrated IR spectroscopy, scanning electron microscopy and powder X-ray diffraction approach

2015 ◽  
Vol 48 (6) ◽  
pp. 1794-1804 ◽  
Author(s):  
Paramita Chatterjee ◽  
Samiran Pramanik ◽  
Alok Kumar Mukherjee
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Kidney Stones ◽  
Urinary Calculi ◽  
X Ray Diffraction ◽  
Carbonated Hydroxyapatite ◽  
X Ray ◽  
The Core ◽  
Different Parts ◽  
Scanning Electron

A combination of IR spectroscopy, scanning electron microscopy (SEM) and powder X-ray diffraction has been used to analyze the compositional and architectural variation across the different parts (core, middle and outer layers) of five human urinary calculi (KS1–KS5) from eastern India. Rietveld quantitative phase analysis using X-ray powder diffraction revealed that the composition of the core regions in KS1–KS3 and KS5 is exclusively whewellite, whereas in KS4 it is a mixture of whewellite (84.5 wt%) and carbonated hydroxyapatite (15.5 wt%). While one of the renal stones, KS1, is composed of only whewellite in all three regions, a distinct variation in phase composition from the core towards the periphery has been observed in KS2–KS5. A drastic change in phase composition has been noted in KS5, with the major constituent phases in the core, middle and outer layers as whewellite (100.0 wt%), anhydrous uric acid (60.7 wt%) and carbonated hydroxyapatite (69.6 wt%), respectively. The crystallite size of whewellite in different parts of the kidney stones varies between 91 (1) and 167 (1) nm, while the corresponding sizes of the anhydrous uric acid in KS5 and carbonated hydroxyapatite in KS3 are 107 (1) and 18 (1)–20 (1) nm, respectively. SEM images of the kidney stones showed different levels of organization, resulting from an agglomeration of crystallites with diverse shapes and sizes.

Partitioning of Cesium in Phases Produced by Grouted Waste Injection

1983 ◽  
Vol 26 ◽  
Author(s):  
D. P. Stinton ◽  
E. W. Mcdaniel ◽  
H. O. Weerent
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Stable Cesium ◽  
The Core ◽  
Calcium Silicates ◽  
Hydrated Calcium ◽  
Scanning Electron

ABSTRACTPhases present in injected grouts were characterized by use of optical microscopy, scanning electron microscopy, x-ray diffraction, and β-γ autoradiography. A laboratoryproduced sample containing 1 wt % stable cesium and an actual grout sheet obtained by core drilling were examined. The phases present in these samples were identified, and cesium was found to be absorbed almost entirely by illite clay agglomerates. These clay agglomerates were tightly bound within the grout structure by hydrated calcium silicates. The β-γ autoradiography of the core-drilled sample verified that cesium and other radionuclides were trapped within the 20-year-old grout and had not migrated into trapped shale fragments.

Investigation on Ti-Deoxidized Products Inducing Formation of Intragranular Ferrite

2011 ◽  
Vol 266 ◽  
pp. 229-232
Author(s):  
Jiang Hua Qi ◽  
Jie Wu ◽  
Jin Ping Suo ◽  
Zheng Liang Xue
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Outer Layer ◽  
Precipitation Amount ◽  
The Core ◽  
Intragranular Ferrite ◽  
Transmission Electron ◽  
Deoxidation Process ◽  
Scanning Electron

Steel samples were prepared using a vacuum carbon deoxidization process combined with a final Ti-deoxidation process. Ti-deoxidized products inducing formation of intragranular ferrite (IGF) was investigated by using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) through various specimens by different methods, as follows: metallographic specimens, electrolyzation, ion thinning technology, RTO method and so on. Mn is found to be more extensively distributed than S in the core of inclusion, which shows that Ti2O3 has character of absorbing Mn. The Mn-depleted zone (MDZ) exists in the peripheral steel of inclusion, the more near the inclusion, the more obvious depletion of Mn. It is also found that outer layer of inclusion exists S-rich and Mn depletion area in specimens prepared using RTO method under TEM. Mn- depleted zone in steel and Mn-depleted but S-rich layer in the periphery of the inclusion indicate that Mn diffuses and diverts is step by step in steel and inclusion, and the extent of S-rich and Mn depletion area should be related with degree of Mn absorbed by Ti2O3 and original precipitation amount of MnS.

Weathering of a Basalt by Pertusaria Corallina

1980 ◽  
Vol 12 (3) ◽  
pp. 277-290 ◽  
Author(s):  
D. Jones ◽  
M. J. Wilson ◽  
J. M. Tait
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Oxalic Acid ◽  
Clay Minerals ◽  
Plagioclase Felspar ◽  
Alumino Silicate ◽  
Mineral Alteration ◽  
Silicate Materials ◽  
Scanning Electron

AbstractThe weathering phenomena resulting from the encrustation of basalt by Pertusaria corallina have been studied by scanning electron microscopy and a variety of other techniques. The rock consists largely of plagioclase felspar (labradorite) and ferromagnesian minerals, the latter often being replaced by hydrothermally formed ferruginous clay minerals. Lichen weathering results in the extensive etching of the primary rock-forming minerals, particularly labradorite, and in the degradation of the clay minerals to yield a thin ochreous crust of poorly-ordered ferruginous (ferrihydrite) and alumino-silicate materials. These changes are brought about principally by the oxalic acid secreted by the mycobiont, a conclusion supported by observations following experimental mineral alteration.

scholarly journals Resistance to compression and microstructure of concrete manufactured with supersulfated cements-based materials of volcanic origin exposed to a sulphate environment

2018 ◽  
Vol 9 (1) ◽  
pp. 106-116
Author(s):  
Erick Edgar Maldonado Bandala ◽  
Karina Cabrera Luna ◽  
José Ivan Escalante García ◽  
Demetrio Nieves Mendoza
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Energy Dispersive Spectroscopy ◽  
Energy Dispersive ◽  
Hydration Products ◽  
Volcanic Origin ◽  
Volcanic Material ◽  
Laboratory Conditions ◽  
Scanning Electron

This research presents the results of concretes made with supersulfated cements (SSC) volcanic material bases. The concretes were cured under two regimes one for 24 h at 25 ° C and one for 22 h at 60 ° C and then at 25 ° C. The specimens were exposed to two conditions, dry under laboratory conditions and immersed in a solution with 3.5% CaSO 4 at 25 ° C for up to 180 days. After 180 days, the concrete with a 5% An-10% PC-10% CaO-75% PM cementant exposed to the CaSO4 solution achieved a compressive strength of 46 MPa and 44 MPa dry under conditions of laboratory. The microstructure was analyzed by scanning electron microscopy, energy dispersive spectroscopy and XRD, showing that the main hydration products are C-S-H and ettringite.

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