scholarly journals Динамика осыпей в центральной части гор Дел-Урэкчэн (Северное Приохотье) на основе лихенометрических данных

2021 ◽  
pp. 71-81
Author(s):  
P. P. Kolegov ◽  
Keyword(s):  
River Basin ◽  
Exposure Time ◽  
Rock Glaciers ◽  
Slope Rock ◽  
Displacement Speed

The paper presents the results of the research on the colluvial cone (talus) dynamics study by using the lichenometric method in the basin of the Agan and Nankala rivers (Arman River basin). The obtained values of the exposure time of taluses are 385 ± 114 yr, the displacement speed of the clastic cover in the talus is 0.48 ± 0.23 m/yr. The distal parts of some cones, confined to the rocky slopes of the northern exposure, have been transformed into slope rock glaciers.

Landforms and ground ice as evidence of the source of H2O in permafrost

1989 ◽  
Vol 13 (3) ◽  
pp. 367-390 ◽  
Author(s):  
Stuart A. Harris
Keyword(s):  
Frozen Ground ◽  
Secondary Importance ◽  
Glacial Ice ◽  
Initial Formation ◽  
Ice Accumulation ◽  
Potential Sources ◽  
Rock Glaciers ◽  
Slope Rock ◽  
Ice Content ◽  
Peat Plateaus

Selected landforms and the ice in permafrost may be used as indicators of the direction of moisture input into perennially frozen ground. Accumulation of ice from meteoric sources from above may be the most widespread process, being dominant in the palsas, peat plateaus, and near-slope rock glaciers studied so far. It is also the main source of ice accumulation in permafrost. Pingos and seasonal frost mounds are the result of injection of ground water from below. The resulting ice content usually exceeds 90% by volume and some massive icy beds in Arctic Canada may also form in this way. Glacial ice is also proven as a source for some massive icy beds and may represent an Arctic form of ice stagnation. Segregation of ice by water moving to the freezing plane is very important in active layer processes and the initial formation of peat plateaus and palsas, but is probably of secondary importance thereafter. More work is needed to confirm these relationships and to prove the origin of near-glacier rock glaciers. However, if these relationships prove reliable, then the landforms can be used as indicators of potential sources of ice so that foundation designs can be modified to minimize heaving problems.

scholarly journals Rock glacier and protalus rampart inventory in Las Salinas river basin, Central Andes of Argentina

2021 ◽  
Author(s):  
Ana Paula Forte ◽  
Cristian Daniel Villarroel ◽  
María Yanina Esper Angillieri
Keyword(s):  
River Basin ◽  
Central Andes ◽  
Slope Aspect ◽  
Optical Remote Sensing ◽  
Rock Glacier ◽  
Study Region ◽  
Hydrological System ◽  
Rock Glaciers ◽  
Salinas River ◽  
The Relationship

This paper presents a detailed rock glacier and protalus rampart inventory from Las Salinas river basin, an arid subtropical mountain hydrological system (between 31°02’ and 31°22’ S latitude) located in the northern sector of the Central Andes of Argentina, where permafrost and cryogenic processes prevail. The inventory is based on a geomorphological characterization by means of optical remote sensing and field description data. The study region covers 630 km2, with 3.25% of the area containing 405±8.2 rock glaciers and protalus ramparts in total, of which 231±2.5 are considered protalus rampart and 49±2 are considered active, 61±1 inactive and 64±3 fossil rock glaciers. Frequency ratio and logistic regression were used as statistical methods to determine the relationship between the distribution of these periglacial landforms and different geological, morphometric and climatic variables as elevation, potential incoming solar radiation, slope, aspect and lithology. Results show that elevation, lithology, and aspect are the most influencing factors for the occurrence of active rock glaciers. According to rock glaciers and protalus ramparts distribution, the permafrost occurrence probability is above 3690 m a.s.l. (current and high periglacial environment). However, some inactive rock glaciers and protalus rampart were found below this elevation, thus between 3300 and 3690 m a.s.l. the landscapes are dominated by an unstable periglacial environment.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Structure images of Si, Ge and Mos2 crystals and some application to radiation damage studies

1978 ◽  
Vol 36 (1) ◽  
pp. 292-293 ◽  
Author(s):  
K. Izui ◽  
T. Nishida ◽  
S. Furuno ◽  
H. Otsu ◽  
S. Kuwabara
Keyword(s):  
Radiation Damage ◽  
Exposure Time ◽  
Gaussian Distribution ◽  
Intensity Distribution ◽  
Chromatic Aberration ◽  
Magnetic Lens

Recently we have observed the structure images of silicon in the (110), (111) and (100) projection respectively, and then examined the optimum defocus and thickness ranges for the formation of such images on the basis of calculations of image contrasts using the n-slice theory. The present paper reports the effects of a chromatic aberration and a slight misorientation on the images, and also presents some applications of structure images of Si, Ge and MoS2 to the radiation damage studies.(1) Effect of a chromatic aberration and slight misorientation: There is an inevitable fluctuation in the amount of defocus due to a chromatic aberration originating from the fluctuations both in the energies of electrons and in the magnetic lens current. The actual image is a results of superposition of those fluctuated images during the exposure time. Assuming the Gaussian distribution for defocus, Δf around the optimum defocus value Δf0, the intensity distribution, I(x,y) in the image formed by this fluctuation is given by

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