scholarly journals The Location of Impurities in Antarctic Ice

1988 ◽  
Vol 11 ◽  
pp. 194-197 ◽  
Author(s):  
E.W. Wolff ◽  
R. Mulvaney ◽  
K. Oates
Keyword(s):  
Freezing Point ◽  
Ice Sheet ◽  
Chemical Substance ◽  
Triple Junctions ◽  
Sea Salts ◽  
X Ray ◽  
Cold Stage ◽  
Micro Analysis ◽  
The Antarctic ◽  
Scanning Electron

Analysis of an ice sample with an estimated age of 125 years, from the Antarctic Peninsula, using a scanning electron microscope with a cold stage and an X-ray micro-analysis facility, shows that H2SO4 occurs mainly at triple junctions. Sea salts show no such localization. The different behaviour may be due to the freezing-point behaviour of each chemical substance, and to the effect this has both in the atmosphere and during recrystallization in the ice sheet. If this finding applies generally to other parts of the Antarctic ice sheet, it has major implications for many of the physical properties of Antarctic ice. In particular, it leads to a better understanding of the d.c. electrical conductivity of such ice.

scholarly journals The Location of Impurities in Antarctic Ice

1988 ◽  
Vol 11 ◽  
pp. 194-197 ◽  
Author(s):  
E.W. Wolff ◽  
R. Mulvaney ◽  
K. Oates
Keyword(s):  
Freezing Point ◽  
Ice Sheet ◽  
Chemical Substance ◽  
Triple Junctions ◽  
Sea Salts ◽  
X Ray ◽  
Cold Stage ◽  
Micro Analysis ◽  
The Antarctic ◽  
Scanning Electron

Analysis of an ice sample with an estimated age of 125 years, from the Antarctic Peninsula, using a scanning electron microscope with a cold stage and an X-ray micro-analysis facility, shows that H2SO4 occurs mainly at triple junctions. Sea salts show no such localization. The different behaviour may be due to the freezing-point behaviour of each chemical substance, and to the effect this has both in the atmosphere and during recrystallization in the ice sheet. If this finding applies generally to other parts of the Antarctic ice sheet, it has major implications for many of the physical properties of Antarctic ice. In particular, it leads to a better understanding of the d.c. electrical conductivity of such ice.

On the thickness of the Antarctic ice, and its relations to that of the glacial epoch

2021 ◽  
pp. 1-8
Author(s):  
James CROLL ◽  
David SUGDEN
Keyword(s):  
Thermal Regime ◽  
Freezing Point ◽  
Ice Sheet ◽  
Heat Sources ◽  
Mean Velocity ◽  
Point Estimates ◽  
Glacial Epoch ◽  
Antarctic Continent ◽  
Global Sea Level ◽  
The Antarctic

ABSTRACT At a time when nobody has yet landed on the Antarctic continent (1879), this presentation and accompanying paper predicts the morphology, dynamics and thermal regime of the Antarctic ice sheet. Mathematical modelling of the ice sheet is based on the assumptions that the thickness of tabular icebergs reflects the average thickness of the ice at the margin and that the surface gradients are comparable to those of reconstructed former ice sheets in the Northern Hemisphere. The modelling shows that (a) ice is thickest near the centre at the South Pole and thins towards the margin; (b) the thickness at the pole is independent of the amount of snowfall at that place; and (c) the mean velocity at the margin, assuming a mean annual snowfall of two inches per year, is 400–500 feet per year. The thermal regime of the ice sheet is influenced by three heat sources – namely, the bed, the internal friction of ice flow and the atmosphere. The latter is the most significant and, since ice has a downwards as well as horizontal motion, this carries cold ice down into the ice sheet. Since the temperature at which ice melts is lowered by pressure at a rate of 0.0137 °F for every atmosphere of pressure (something known since 1784), much of the ice sheet and its base must be below the freezing point. Estimates of the thickness of ice at the centre depend closely on the surface gradients assumed and range between 3 and 24 miles. Such uncertainty is of concern since both the volume and gravitational attraction of the ice mass have an effect on global sea level. In order to improve our estimate of the volume of ice, we will have to wait 76 years for John Glen to develop a realistic flow law for ice.

scholarly journals ASSESSMENT OF DETERIORATION PROCESS IN EXPOSED CARVED LIMESTONE FALSE DOOR OF ABUSIR ARCHAEOLOGICAL AREA

2021 ◽  
Vol 21 (1) ◽  
pp. 221-234
Author(s):  
HESHAM HAKEM ◽  
MONA F. ALI ◽  
MIROSLAV BÁRTA ◽  
ASHRAF YOUSSEF
Keyword(s):  
X Ray Diffraction ◽  
Polarizing Microscopy ◽  
X Ray ◽  
Intermediate Period ◽  
Deterioration Process ◽  
Different Depths ◽  
First Intermediate Period ◽  
Analysis System ◽  
Micro Analysis ◽  
Scanning Electron

Carved limestone false door dating back to the late Sixth Dynasty or the First Intermediate Period in Abusir archaeological area suffers from many physiochemical and mechanical deterioration factors, which lead to various deterioration phenomena, such as distort the carvings, decorations, the disappearance of paint, cracks in different depths, and salt calcification. It was found in the fill of Shaft 5 in the tomb AS 79 at Abusir South, Excav. No. 9/AS79/2015 and located in the storeroom of Czech Excavation in Abusir area. The current work aims to study the type of limestone which the false door is made of, and to know if there were colors on the false door or not, also to know if there were deterioration mechanisms that affect the carved limestone false doors of Abusir to evaluate the deterioration ratio in stone structure and the effects of surrounding environmental factors on stone. The investigation and characterization processes of archaeological limestone samples were carried out by polarizing microscopy (PLM), optical microscopy (OM), scanning electron microscopy (SEM-EDX) micro-analysis system, X-ray diffraction (XRD), X-ray fluorescence (XRF), and Fourier transform infrared spectroscopy (FTIR). The results revealed that the limestone material of the false door belongs to micrite limestone with very fine grains and needs to be conserved.

X-ray microanalysis of frozen-hydrated bulk biological specimens: fundamental considerations

1978 ◽  
Vol 36 (2) ◽  
pp. 134-135
Author(s):  
W.C. Low ◽  
P.A. Burgio ◽  
L.F. Allard ◽  
S.L. BeMent ◽  
W.C. Bigelow ◽  
...  
Keyword(s):  
Biological Tissue ◽  
Ice Crystals ◽  
Tissue Fixation ◽  
Atmospheric Conditions ◽  
Bulk Specimen ◽  
X Ray ◽  
Ion Translocation ◽  
Cold Stage ◽  
Bulk Tissue ◽  
Scanning Electron

X-ray microanalysis and scanning electron microscopy used in conjunction with cold-stage techniques to examine frozen-hydrated bulk biological tissue is a promising method to determine the concentration and distribution of diffusible elements which are typically distorted by conventional techniques of biological tissue fixation. The proper application of this method, however, requires an understanding of the freezing and sublimation processes in bulk biological specimens, and the interaction of the electron beam with the bulk specimen in the frozen-hydrated state. These factors have been evaluated and are discussed below.One of the fundamental considerations in the examination of cryofixed bulk tissue is the formation of exogenous and endogenous ice crystals within the specimen or upon the surface of the specimen which can lead to tissue distortion and ion translocation. Techniques to minimize the exposure of the specimen to atmospheric conditions and to eleminate the formation of exogenous ice crystals have been developed by Burgio et al. (1978a), and Echlin and Moreton (1974).

scholarly journals Application of scanning electron microscopy to x-ray analysis of frozen-hydrated sections. I. Specimen handling techniques.

1981 ◽  
Vol 88 (2) ◽  
pp. 257-267 ◽  
Author(s):  
A J Saubermann ◽  
P Echlin ◽  
P D Peters ◽  
R Beeuwkes
Keyword(s):  
Specimen Handling ◽  
X Ray ◽  
Water Fraction ◽  
Tissue Sections ◽  
Cold Stage ◽  
Mass Fractions ◽  
Wet Weight ◽  
Cellular Compartments ◽  
Scanning Electron

X-ray microanalysis of frozen-hydrated tissue sections permits direct quantitative analysis of diffusible elements in defined cellular compartments. Because the sections are hydrated, elemental concentrations can be defined as wet-weight mass fractions. Use of these techniques should also permit determination of water fraction in cellular compartments. Reliable preparative techniques provide flat, smooth, 0.5 micrometers-thick sections with little elemental and morphological disruption. The specimen support and transfer system described permits hydrated sections to be transferred to the scanning electron microscope cold stage for examination and analysis without contamination or water loss and without introduction of extraneous x-ray radiation.

scholarly journals Brief communication: Spatial and temporal variations in surface snow chemistry along a traverse from coastal East Antarctica to the ice sheet summit (Dome A)

2021 ◽  
Vol 15 (2) ◽  
pp. 1087-1095
Author(s):  
Guitao Shi ◽  
Hongmei Ma ◽  
Zhengyi Hu ◽  
Zhenlou Chen ◽  
Chunlei An ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ice Sheet ◽  
Temporal Variations ◽  
Sea Salt ◽  
Biogenic Emissions ◽  
Dome A ◽  
Sea Salts ◽  
Snow Chemistry ◽  
Surface Snow ◽  
The Antarctic

Abstract. To better understand snow chemistry in different environments across the Antarctic ice sheet, we investigated snow ions on a traverse from the coast to Dome A. Results show that the non-sea-salt (nss) fractions of K+, Mg2+, and Ca2+ are mainly from terrestrial particle mass and nssCl− is associated with HCl. Spatially, the non-sea-salt fractions of ions to the totals are higher in the interior areas than on the coast, and seasonally, the proportions are higher in summer than in winter. Negative nssSO42- on the coast indicates sea salts from the sea ice, and marine biogenic emissions dominate snow SO42- in interior areas throughout the year.

Microanalysis of Particulate Materials

1973 ◽  
Vol 31 ◽  
pp. 248-249
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Particulate Material ◽  
Particulate Materials ◽  
X Ray ◽  
Qualitative And Quantitative ◽  
Chemical Determination ◽  
Analysis System ◽  
Micro Analysis ◽  
Scanning Electron

The scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysis system is probably the best combination instrument for the micro- analysis of particulate material. The versatility of image forming capabilities with the SEM and the rapid chemical determination which are possible with the EDX are the most notable advantages. The purpose of this paper is to illustrate some of the qualitative and quantitative techniques of the system and their applicability to the analysis of particulate materials. An AMR 1000 scanning electron microscope and an Ortec X-ray microanalysis system were employ d to generate the results discussed below.

X-RAY Microanalysis of Selected Coelenterate Statoliths

1985 ◽  
Vol 65 (3) ◽  
pp. 617-627 ◽  
Author(s):  
David M. Chapman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Atomic Number ◽  
Elemental Analysis ◽  
Energy Dispersive Spectrometer ◽  
X Ray ◽  
Relationship Of ◽  
Micro Analysis ◽  
The Relationship ◽  
Scanning Electron

When scanning electron microscopy became integrated with X-ray micro-analysis, it became an easy matter to localize an object and perform a semi-quantitative elemental analysis of atoms of atomic number 11 or higher using an energy dispersive spectrometer. This technique is used in the present study to determine the chemistry of the statoliths of eight hydromedusae, two scyphomedusae, one cubozoan and a ctenophore with respect to their comparative biomineralization and the relationship of the mineral to their taxonomy.

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