scholarly journals Reconnaissance scale geochemical survey in central and western North Greenland Preliminary results concerning zinc and barium

1985 ◽  
Vol 126 ◽  
pp. 95-104
Author(s):  
A Steenfelt
Keyword(s):  
Grain Size ◽  
Regional Distribution ◽  
Sediment Samples ◽  
X Ray ◽  
North West ◽  
Preliminary Results ◽  
The Matrix ◽  
Lower Palaeozoic ◽  
High Level ◽  
North Greenland

Stream sediment samples were colleeted at a density of 1 sample per 30 km2 in Warming Land, Wulff Land, Nares Land, Nansen Land and along Navarana Fjord. The minus 0.1 mm grain size fraetion of the samples was analysed by X-ray fluorescenee for 30 elements. The regional distribution pattem for the contents of Zn and Ba reflects the lithological changes. Lowest values for both elements occur in the lower Palaeozoic earbonate platform and the contents gradually inerease northwards in the flysch deposits of the Silurian basin to a high level for both elements in samples from the folded Cambrian basin deposits in Nansen Land. Anomalously high values of Zn and Ba at Navarana Fjord and at north-west Nares Land are associated with a thin Cambro-Ordovician unit of blaek dolomitie mudstones. Reeonnaissanee zine anomalies and the occurrenee of massive sphalerite in the matrix of a breccia zone at Navarana Fjord are taken as indications of a major zine mineralising event.

Effect of Grain Size on the Isothermal Oxidation of Fe-33Ni-19Cr Alloys at 700 °C

2013 ◽  
Vol 845 ◽  
pp. 56-60
Author(s):  
Noraziana Parimin ◽  
Esah Hamzah ◽  
Astuty Amrin
Keyword(s):  
Grain Size ◽  
Oxidation Behavior ◽  
Annealing Treatment ◽  
Isothermal Oxidation ◽  
Coarse Grain ◽  
X Ray ◽  
Fine Grain ◽  
The Matrix ◽  
Different Temperatures ◽  
Different Grain Size

The isothermal oxidation behavior of two different grain size of Fe-33Ni-19Cr alloys was investigated at 700 °C in laboratory air. Different grain size of alloyed was made of solution annealing treatment at different temperatures, namely, 1050 °C and 1150 °C for fine and coarse grain, respectively. Optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were employed in this study to analyze the oxidation behavior of solution-annealed samples. Results indicate that the fine grain size solution-annealed alloys possess a better oxidation resistance and reduced oxidation rate than the coarse grain. The differences observed are attributed to the finer grains increasing the relaxation of the oxide scale stress and improving the adhesion of the oxide layer on the matrix.

scholarly journals Experimental Investigation on Drying and Wetting of GMZ Bentonite Using X-Ray Tomography and Volumetric Digital Image Correlation Technique

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Liufeng Chen ◽  
Kang Li ◽  
Diansen Yang
Keyword(s):  
Image Correlation ◽  
Correlation Technique ◽  
Gmz Bentonite ◽  
Swelling Properties ◽  
Full Field ◽  
X Ray ◽  
The Matrix ◽  
Swelling Characteristics ◽  
Swelling Strain ◽  
High Level

To investigate the shrinking and swelling properties of Gao-Miao-Zi (GMZ) bentonite, which has been considered as engineering barriers for high-level radioactive nuclear waste disposal in China, drying and wetting tests were carried out. The microstructure of the material at each hydric state was recorded using X-ray tomography (X-CT). The 3D images of the material were analyzed using digital volume correlation (DVC) technique, and the full-field strains at mesoscale (i.e., in the order of clay aggregate) during drying and wetting were quantified. The results show that the GMZ bentonite exhibits notable swelling characteristics during wetting and the swelling strain of the material is up to 8% at mesoscale. The full-field strain in 3D of the material is heterogeneous, anisotropic, and irreversible during drying and wetting. The corresponding deformation mechanisms are discussed. Two different swelling mechanisms were also identified: traction occurs in the interface between the matrix and inclusions during swelling; pre-existing fissure closes during swelling.

scholarly journals TOURMALINITE VEINS AND BRECCIAS FROM THE SYMVOLON-KAVALA PLUTON, NORTHERN GREECE: PETROGENETIC PRELIMINARY RESULTS

2017 ◽  
Vol 50 (4) ◽  
pp. 2079 ◽  
Author(s):  
S. Xydous ◽  
A. Magganas ◽  
P. Pomonis ◽  
A. Kokkinakis
Keyword(s):  
Grain Size ◽  
Host Rock ◽  
Hydrothermal Fluids ◽  
Tectonic Unit ◽  
Brittle Deformation ◽  
Northern Greece ◽  
Lower Miocene ◽  
Preliminary Results ◽  
Deformation Regime ◽  
The Matrix

A previously undescribed tourmalinite rock consisting of tourmaline-rich veins and breccias occurs within the Lower Miocene Symvolon-Kavala granodiorite pluton, which intrudes the Lower Tectonic Unit of the Rhodope Metamorphic Province. Tourmaline, usually with crypto- to micro-crystalline grain size, is abundant within the matrix of breccias, also forming along with quartz and host rock clasts massive veins and injections in the fractures of the pluton. Field relations indicate that the tourmaline veins and breccias most likely formed in a brittle deformation regime, overprinting the previously developed foliation of the pluton. In addition, mineralogical and textural observations indicate that the precipitation of tourmaline was a result of cooling of B-rich hydrothermal fluids, implying for a possible magmatic-hydrothermal origin for the studied tourmalinite.

scholarly journals Lower Palaeozoic geology of the western part of the North Greenland fold belt

1966 ◽  
Vol 11 ◽  
pp. 11-15
Author(s):  
P.R Dawes
Keyword(s):  
The Arctic ◽  
North Coast ◽  
Northern Coast ◽  
Fold Belt ◽  
North West ◽  
The North ◽  
Lower Palaeozoic ◽  
Inland Ice ◽  
Insight Into ◽  
North Greenland

In the summers 1965 and 1966 reconnaissance mapping of 10 000 km2 of the rarely visited north coast of North Greenland was carried out. In 1965 the investigations were restricted to Hall Land (fig. 3) with a view of obtaining an insight into the stratigraphy of the Ordovician-Silurian succession, while in 1966 work centred on Nyeboe Land and Hendrik Island with cursory exammation of the north-west coast of Wulff Land and the islands in Sherard Osborn Fjord. Both the unfolded rocks of the south towards the Inland Ice and the folded rocks of the northern coast bordering the Robeson Channel and the Arctic Ocean were studied and in the two summers a broad view of the western part of the North Greenland fold belt i. e. west of Peary Land, has been obained.

scholarly journals Uppermost Ordovician and Silurian geology of north-west Peary Land, North Greenland

1979 ◽  
Vol 88 ◽  
pp. 41-49
Author(s):  
J.M Hurst
Keyword(s):  
North West ◽  
Precambrian Rocks ◽  
Comprehensive Account ◽  
Composite Section ◽  
Lower Palaeozoic ◽  
North Greenland ◽  
Carbonate Buildup

In 1978 mapping was concentrated in the area of Peary Land, between J. P. Koch Fjord and Odins Fjord, south of a line connecting Nordpasset with Harebugt and the western end of Frederick E. Hyde Fjord (fig. 11 and map l). Prior to this season the Silurian geology of the area was largely unknown. Previous investigations of the platform sediments of Peary Land (Koch, 1923; Troelsen, 1949, 1956; Jepsen, 1971) had mainly concentrated on the older Lower Palaeozoic and Precambrian rocks of southern Peary Land. The only comprehensive account of the Lower Palaeozoic rocks of the platform (including Silurian) of Peary Land, by Peel & Christie (1975) and Christie & Peel (1977) was based on a single composite section in the Børglum Elv district, north of Jørgen Brønlund Fjord (fig. 11). A localised detailed study of a Silurian carbonate buildup in the Børglum Elv region (Mayr, 1976) is the only other aspect of Silurian geology studied in the whole area.

Lateral resolution of the electron microbeam analysis

1978 ◽  
Vol 36 (1) ◽  
pp. 542-543
Author(s):  
H.J. Dudek
Keyword(s):  
Quantitative Analysis ◽  
Depth Resolution ◽  
Lateral Resolution ◽  
Cylindrical Particle ◽  
Correction Procedure ◽  
X Ray ◽  
Element Concentrations ◽  
Microbeam Analysis ◽  
The Matrix

The chemical inhomogenities in modern materials such as fibers, phases and inclusions, often have diameters in the region of one micrometer. Using electron microbeam analysis for the determination of the element concentrations one has to know the smallest possible diameter of such regions for a given accuracy of the quantitative analysis.In th is paper the correction procedure for the quantitative electron microbeam analysis is extended to a spacial problem to determine the smallest possible measurements of a cylindrical particle P of high D (depth resolution) and diameter L (lateral resolution) embeded in a matrix M and which has to be analysed quantitative with the accuracy q. The mathematical accounts lead to the following form of the characteristic x-ray intens ity of the element i of a particle P embeded in the matrix M in relation to the intensity of a standard S

Aspects of microanalysis in a transmission electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 510-511
Author(s):  
R. Sinclair ◽  
B.E. Jacobson
Keyword(s):  
Grain Size ◽  
Electron Beam ◽  
Electron Microscope ◽  
Chemical Analysis ◽  
Transmission Electron Microscope ◽  
Vapor Deposition ◽  
Critical Currents ◽  
X Ray ◽  
Fine Grain ◽  
Transmission Electron

INTRODUCTIONThe prospect of performing chemical analysis of thin specimens at any desired level of resolution is particularly appealing to the materials scientist. Commercial TEM-based systems are now available which virtually provide this capability. The purpose of this contribution is to illustrate its application to problems which would have been intractable until recently, pointing out some current limitations.X-RAY ANALYSISIn an attempt to fabricate superconducting materials with high critical currents and temperature, thin Nb3Sn films have been prepared by electron beam vapor deposition [1]. Fine-grain size material is desirable which may be achieved by codeposition with small amounts of Al2O3 . Figure 1 shows the STEM microstructure, with large (∽ 200 Å dia) voids present at the grain boundaries. Higher quality TEM micrographs (e.g. fig. 2) reveal the presence of small voids within the grains which are absent in pure Nb3Sn prepared under identical conditions. The X-ray spectrum from large (∽ lμ dia) or small (∽100 Ǻ dia) areas within the grains indicates only small amounts of A1 (fig.3).

Analysis and lattice imaging of a transitional event on garnets

1978 ◽  
Vol 36 (1) ◽  
pp. 270-271
Author(s):  
J.Y. Laval
Keyword(s):  
Yttrium Iron Garnet ◽  
Reciprocal Lattice ◽  
Transitional Zone ◽  
Lattice Imaging ◽  
Yttrium Iron ◽  
X Ray ◽  
Ionic Process ◽  
The Matrix ◽  
High Resolution Technique ◽  
Iron Garnet

The exsolution of magnetite from a substituted Yttrium Iron Garnet, containing an iron excess may lead to a transitional event. This event is characterized hy the formation of a transitional zone at the center of which the magnetite nucleates (Fig.1). Since there is a contrast between the matrix and these zones and since selected area diffraction does not show any difference between those zones and the matrix in the reciprocal lattice, it is of interest to analyze the structure of the transitional zones.By using simultaneously different techniques in electron microscopy, (oscillating crystal method microdiffraction and X-ray microanalysis)one may resolve the ionic process corresponding to the transitional event and image this event subsequently by high resolution technique.

Phase identification in SiC whisker reinforced Al2O3-R2O3-based composites

1992 ◽  
Vol 50 (1) ◽  
pp. 152-153
Author(s):  
C.M. Sung ◽  
K.J. Ostreicher ◽  
M.L. Huckabee ◽  
S.T. Buljan
Keyword(s):  
Analytical Electron Microscopy ◽  
Phase Identification ◽  
Reinforced Composites ◽  
Ion Milling ◽  
X Ray ◽  
Binary Oxides ◽  
Analytical Electron ◽  
The Matrix ◽  
Second Phases ◽  
Convergent Beam

A series of binary oxides and SiC whisker reinforced composites both having a matrix composed of an α-(Al, R)2O3 solid solution (R: rare earth) have been studied by analytical electron microscopy (AEM). The mechanical properties of the composites as well as crystal structure, composition, and defects of both second phases and the matrix were investigated. The formation of various second phases, e.g. garnet, β-Alumina, or perovskite structures in the binary Al2O3-R2O3 and the ternary Al2O3-R2O3-SiC(w) systems are discussed.Sections of the materials having thicknesses of 100 μm - 300 μm were first diamond core drilled. The discs were then polished and dimpled. The final step was ion milling with Ar+ until breakthrough occurred. Samples prepared in this manner were then analyzed using the Philips EM400T AEM. The low-Z energy dispersive X-ray spectroscopy (EDXS) data were obtained and correlated with convergent beam electron diffraction (CBED) patterns to identify phase compositions and structures. The following EDXS parameters were maintained in the analyzed areas: accelerating voltage of 120 keV, sample tilt of 12° and 20% dead time.

Improving x-ray map resolution with image restoration techniques

1996 ◽  
Vol 54 ◽  
pp. 598-599
Author(s):  
Richard B. Mott ◽  
John J. Friel ◽  
Charles G. Waldman
Keyword(s):  
Image Restoration ◽  
Hubble Space Telescope ◽  
Extensive Literature ◽  
Small Object ◽  
X Rays ◽  
X Ray ◽  
Mapping Parameters ◽  
The Matrix ◽  
The 1960S ◽  
Map Resolution

X-rays are emitted from a relatively large volume in bulk samples, limiting the smallest features which are visible in X-ray maps. Beam spreading also hampers attempts to make geometric measurements of features based on their boundaries in X-ray maps. This has prompted recent interest in using low voltages, and consequently mapping L or M lines, in order to minimize the blurring of the maps.An alternative strategy draws on the extensive work in image restoration (deblurring) developed in space science and astronomy since the 1960s. A recent example is the restoration of images from the Hubble Space Telescope prior to its new optics. Extensive literature exists on the theory of image restoration. The simplest case and its correspondence with X-ray mapping parameters is shown in Figures 1 and 2.Using pixels much smaller than the X-ray volume, a small object of differing composition from the matrix generates a broad, low response. This shape corresponds to the point spread function (PSF). The observed X-ray map can be modeled as an “ideal” map, with an X-ray volume of zero, convolved with the PSF. Figure 2a shows the 1-dimensional case of a line profile across a thin layer. Figure 2b shows an idealized noise-free profile which is then convolved with the PSF to give the blurred profile of Figure 2c.

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