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111.
Xavier Ruiz Laureano Ramírez-Piscina Jaume Casademunt 《Astrophysics and Space Science》2001,276(1):135-140
We study the convective flow induced by residual accelerations in microgravity conditions for different geometric arrangements which are relevant to crystal growth experiments. We consider both constantand oscillating acceleration and focus mostly on the transient relaxation dynamics. Results are relevant to estimate impact of more realistic residual accelerations in crystal growth experiments. 相似文献
112.
B. N. Ashoka Kumar V. C. Babu S. Seetha V. Girish S. K. Gupta Ram Sagar S. Joshi P. Narang 《Journal of Astrophysics and Astronomy》2001,22(1):131-144
The design and performance of a portable three channel photometer installed at the Uttar Pradesh State Observatory (UPSO),
Naini Tal is described. The photometer is modular and the whole unit can be disassembled as individual channels such that
the system can also be used as a single channel or two channel photometer. The system also has provision to monitor a guide
star. The instrument was put into operation since November 1999 on the 1m Sampurnanand telescope at UPSO, Naini Tal. Since
then, it is used extensively for the ‘Survey of rapidly oscillating Ap (roAp) stars in the northern sky’ from UPSO. Observational
results using this new photometer in its initial phase of operation are discussed. The advantage of having continuous sky
measurement is demonstrated. 相似文献
113.
A. K. Pandey K. Upadhyay K. Ogura Ram Sagar V. Mohan H. Mito H. C. Bhatt B. C. Bhatt 《Monthly notices of the Royal Astronomical Society》2005,358(4):1290-1308
UBVRI CCD photometry in a wide field around two young open clusters, NGC 663 and 654, has been carried out. Hα and polarimetric observations for the cluster NGC 654 have also been obtained. We use the photometric data to construct colour–colour and colour–magnitude diagrams, from which we can investigate the reddening, age, mass and evolutionary states of the stellar contents of the these clusters. The reddening across the cluster regions is found to be variable. There is evidence for anomalous reddening law in both clusters; however, more infrared and polarimetric data are needed to conclude about the reddening law. Both clusters are situated at about a distance of 2.4 kpc. Star formation in both clusters is found to be a continuous process. In the case of NGC 663, star formation seems to have taken place sequentially, in the sense that formation of low-mass stars precedes the formation of most massive stars. Whereas, in the case of NGC 654, formation of low-mass stars did not cease after the formation of most massive stars in the cluster. 相似文献
114.
The equation of motion written down using a metric obtained from the Kerr metric allows us to get both the deflection angle of light ray bending by the gravitational field of the Sun and its corresponding time delay. We reproduce the experimental data of Epstein-Shapiro and also it is in accordance with the theoretical results obtained by Brumberget al. (1990) using another approach to this problem.Presented at the 2nd UN/ESA Workshop, held in Bogotá, Colombia, 9–13 November, 1992. 相似文献
115.
Romero Jorge E. Vergara-Pinto Francisca Aguilar Germn Garcs Alex Montserrat Santiago 《Landslides》2022,19(4):865-883
Landslides - An extreme precipitation event produced catastrophic debris flows in central Chile during 29–31 January 2021 (austral summer). Our study focuses on the triggering factors and... 相似文献
116.
Acta Geotechnica - This paper presents a novel, exact, semi-analytical solution for the quasi-static drained expansion of a cylindrical cavity in soft soils with fabric anisotropy and structure.... 相似文献
117.
Jordão Helga Azevedo Leonardo Sousa António Jorge Soares Amílcar 《Mathematical Geosciences》2022,54(7):1165-1182
Mathematical Geosciences - In complex geological environments, the spatial domain characterization of different ore types has been one of the most important challenges in the assessment of mineral... 相似文献
118.
Tsering Karma Shrestha Manish Shakya Kiran Bajracharya Birendra Matin Mir Lozano Jorge Luis Sanchez Nelson Jim Wangchuk Tandin Parajuli Binod Bhuyan Md Arifuzzaman 《Natural Hazards》2022,110(3):1821-1845
Natural Hazards - The Hindu Kush Himalayan region is extremely susceptible to periodic monsoon floods. Early warning systems with the ability to predict floods in advance can benefit tens of... 相似文献
119.
120.
Pennsylvanian carbonate platforms adjacent to deltaic systems in an active marine foreland basin (Escalada Fm., Cantabrian Zone,NW Spain) 下载免费PDF全文
Juan Ramón Bahamonde Oscar Merino‐Tomé Giovanna Della Porta Elisa Villa 《Basin Research》2015,27(2):208-229
The Pennsylvanian marine foreland basin of the Cantabrian Zone (NW Spain) is characterized by the unique development of kilometre‐size and hundred‐metre‐thick carbonate platforms adjacent to deltaic systems. During Moscovian time, progradational clastic wedges fed by the orogen comprised proximal alluvial conglomerates and coal‐bearing deltaic sequences to distal shelfal marine deposits associated with carbonate platforms (Escalada Fm.) and distal clay‐rich submarine slopes. A first phase of carbonate platform development (Escalada I, upper Kashirian‐lower Podolskian) reached a thickness of 400 m, nearly 50 km in width and developed a distal high‐relief margin facing a starved basin, nearly 1000‐m deep. Carbonate slope clinoforms dipped up to 30° and consisted of in situ microbial boundstone, pinching out downslope into calciturbidites, argillaceous spiculites and breccias. The second carbonate platform (Escalada II, upper Podolskian‐lower Myachkovian) developed beyond the previous platform margin, following the basinward progradation of siliciclastic deposits. Both carbonate platforms include: (1) a lower part composed of siliciclastic‐carbonate cyclothems characterized by coated‐grain and ooid grainstones; and (2) a carbonate‐dominated upper part, composed of tabular and mound‐shaped wackestone and algal‐microbial boundstone strata alternating at the decametre scale with skeletal and coated‐grain grainstone beds. Carbonate platforms initiated in distal sectors of the foreland marine shelf during transgressions, when terrigenous sediments were stored in the proximal part, and developed further during highstands of 3rd‐order sequences in a high‐subsidence context. During the falling stage and lowstand systems tracts, deltaic systems prograded across the shelf burying the carbonate platforms. Key factors involved in the development of these unique carbonate platforms in an active foreland basin are: (1) the large size of the marine shelf (approaching 200 km in width); (2) the subsidence distribution pattern across the marine shelf, decreasing from proximal shoreline to distal sectors; (3) Pennsylvanian glacio‐eustacy affecting carbonate lithofacies architecture; and (4) the environmental conditions optimal for fostering microbial and algal carbonate factories. 相似文献