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1.
Radiation exposure and Mission Strategies
for Interplanetary Manned Missions (REMSIM) 总被引:1,自引:0,他引:1
C. Cougnet N. B. Crosby S. Eckersley C. Foullon V. Guarnieri S. Guatelli D. Heynderickx A. Holmes-Siedle C. Lobascio S. Masiello P. Nieminen G. Parisi P. Parodi M. A. Perino M. G. Pia R. Rampini P. Spillantini V. Tamburini E. Tracino 《Earth, Moon, and Planets》2004,94(3-4):279-285
Cosmic radiation is an important problem for human interplanetary missions. The “Radiation Exposure and Mission Strategies for Interplanetary Manned Missions–REMSIM” study is summarised here. They are related to current strategies and countermeasures to ensure the protection of astronauts from radiation during interplanetary missions, with specific reference to: radiation environment and its variability; radiation effects on the crew; transfer trajectories and associated fluences; vehicle and surface habitat concepts; passive and active shielding concepts; space weather monitoring and warning systems. 相似文献
2.
Comparison of numerical models of two debris flows in the Cortina d’ Ampezzo area,Dolomites, Italy 总被引:2,自引:0,他引:2
The accurate prediction of runout distances, velocities and the knowledge of flow rheology can reduce the casualties and property
damage produced by debris flows, providing a means to delineate hazard areas, to estimate hazard intensities for input into
risk studies and to provide parameters for the design of protective measures. The application of most of models that describe
the propagation and deposition of debris flow requires detailed topography, rheological and hydrological data that are not
always available for the debris-flow hazard delineation and estimation. In the Cortina d’Ampezzo area, Eastern Dolomites,
Italy, most of the slope instabilities are represented by debris flows; 325 debris-flow prone watersheds have been mapped
in the geomorphological hazard map of this area. We compared the results of simulations of two well-documented debris flows
in the Cortina d’Ampezzo area, carried on with two different single-phase, non-Newtonian models, the one-dimensional DAN-W
and the two-dimensional FLO-2D, to test the possibility to simulate the dynamic behaviour of a debris flow with a model using
a limited range of input parameters. FLO-2D model creates a more accurate representation of the hazard area in terms of flooded
area, but the results in terms of runout distances and deposits thickness are similar to DAN-W results. Using DAN-W, the most
appropriate rheology to describe the debris-flow behaviour is the Voellmy model. When detailed topographical, rheological
and hydrological data are not available, DAN-W, which requires less detailed data, is a valuable tool to predict debris-flow
hazard. Parameters obtained through back-analysis with both models can be applied to predict hazard in other areas characterized
by similar geology, morphology and climate. 相似文献
3.
The problem of arsenic (As) poisoning in the upper deltaic plain of the Ganga-Bhagirathi river system in the Bengal Basin
of West Bengal, India is an alarming issue. Four blocks (Kaliachak-1, 2, 3 and English Bazar) of Malda district, West Bengal
were critically studied. Geomorphologically, the area exhibits three terraces: the present Youngest terrace (T0-terrace), the Older Shaugaon Surface (T1-terrace) and the Oldest Baikunthapur Surface (T2-terrace). On the basis of numerous measurements, including As-content, pH, DO, specific conductivity and salinity, it was
observed that maximum As-content beyond the permissible limit (0.05 mg/L, Indian standard) occurs within a depth range of
10–30 m with a non-linear distribution pattern. Variance test also found that a block effect was highly significant in an
As-distribution pattern. Mean arsenic level of Kaliachak block-1 is 0.2253 mg/L, followed by Kaliachak-2 with arsenic level
0.1923, Kaliachak-3 with arsenic level 0.1755 and English Bazar with arsenic level 0.1324. The arsenious belt lies mainly
within the Older terrace (T1). The very recent flood plain deposits of silvery white, fine sands lying very close to the Ganga River margin do not contain
significant amounts of As. Elevated As-concentration in the ground water was observed in alluvial sands, grayish white to
brownish in color and occurring away from the Ganga margin. The Oldest terrace (T2) further away from the Ganga margin (e.g.
English Bazar) and Barind surface contains less arsenic. Barind surface acts as a hard capping with ferruginous sands and
lateritic concretions-chocolate, mottled and purple brown in color-occurring northeast of the studied area. Arsenic content
of ground water in the same locality within a radius of ∼ 20 m varies within wide limits. Thus, it poses problem to delineate
its distribution pattern. Such a patchy occurrence possibly could not be explained satisfactorily solely by geomorphology.
Chemical analysis of aquifer clay samples of the cores shows a maximum Ascontent of up to 3 mg/kg, whereas the bulk samples
(sandclay mixture) of the cores contain a maximum of 17 mg/kg As-value. Therefore, it is not always true that clay contains
elevated As-value. 相似文献
4.
Pradeep K. Mukherjee 《Astrophysics and Space Science》1976,41(1):97-104
The structure of the Saturnian rings is compared with the asteroidal belt and the relative importance of the resonance effects and the cosmogonic effects is evaluated. No visible correspondence to the Kirkwood gaps is expected theoretically, nor is there any observational evidence for such effects. The only possible resonance is the 1:1 resonance with Saturn's spin period.Cosmogonic shadow effects are responsible for the main features of the ring structure, including Cassini's division, the limit between the B and C ring, and possibly also Guérin's division. 相似文献
5.
The knowledge of past events is important for the assessment of debris-flow hazard. Amongst the sources of information, documents
from historical archives are particularly important in sites where the debris flows cause damage to urban areas and transportation
routes. The paper analyses the availability of historical documents on debris flows in Northeastern Italy and discusses factors
that can influence the building of time series from archive data both at regional and single basin scales. An increased number
of debris flows was observed in the studied region for the last decades. This could be due both to an increased frequency
of the events and to a larger availability of information: the analysis carried out indicates that the latter factor is probably
the most influencing. The importance of factors, which affect the collection of data, including the conservation of documents
and the presence and fragility of the elements at risk, is stressed in view of a wise use of historical data on debris flows. 相似文献
6.
7.
8.
Sandipan Mukherjee Srabanti Ballav Sandeep Soni Kireet Kumar Utpal Kumar De 《Theoretical and Applied Climatology》2016,125(3-4):489-498
This study investigates the altitudinal variation of dominant modes of summer monsoon intra-seasonal oscillation (ISO) over the Northwest (NWH) and Eastern Himalayan (EH) region using (i) spatially scattered 133 number of station rainfall observations and (ii) latitudinal transect-wise (LT) rainfall variation, obtained from an observed interpolated gridded rainfall data for the period 1995–2004. The altitudinal variation of dominant modes of monsoon ISO were investigated by exploring the strong and weak phases of the principal components of 10–90 days bandpass rainfall data of June to September with respect to location specific station height. Investigation of frequency of days for light and moderate rainfall along with the occurrence of total seasonal rainy days has revealed existence of a rainfall maximum around 2100 m height for the NWH region. Similarly, the total seasonal rainy days of EH region was found to have maxima between 1100 and 1400 m height. Analyses of the spatially scattered station rainfall observation for the NWH region showed that the strong periods of ISO modes exist around 747.9 (±131.7) m and 2227.2 (±100.2) m heights. Over the EH region, the dominant modes of the monsoon ISO were found to be centred around 1200 m. Significant alterations of strong and weak phases of monsoon ISO as a response to altitudinal variation in the mountain surface were observed when latitudinal transect-wise variation of monsoon ISO modes were investigated. 相似文献
9.
The coastal marine atmosphere adjacent to large urban and industrial centers is in general strongly impacted by pollution emissions, resulting in high loading of pollutants in the ambient air. Among the airborne substances are certain trace elements from a variety of emission sources that can serve as micronutrients to marine organisms in coastal waters. High concentrations of such elements in coastal air can result in enhanced air-to-sea deposition fluxes to coastal waters. They could also be transported over the open ocean, affecting the composition of the remote marine atmosphere and then ocean ecosystems. To provide better understanding of the extent of air-to-sea deposition processes on the New Jersey coast, a heavily polluted coastal region on the US East Coast, a synthesis of observation data was carried out for selected trace elements, including Fe, Cd, Cr and Cu, derived from measurements of both size-segregated and bulk aerosol particles, as well as precipitation around the New Jersey coast. The atmospheric input of Hg was also estimated based on measurement data. Results indicated that the total deposition fluxes of most trace elements were higher in Northern coastal NJ compared to Southern coastal NJ, reflecting the differences in the source strengths of these element emissions between the two coastal regions. Dry deposition processes were more significant for common dust-derived elements, particularly Fe and Al, compared with their wet deposition fluxes. However, the processes of precipitation scavenging appeared to be more important for the elements that were often enriched in fine particles including Zn, Cu, Pb and Ni. The removal of Hg from the ambient air was overwhelmingly dominated by atmospheric wet deposition. In the future, atmospheric measurements at more sites on the NJ coast should be performed simultaneously to reduce the spatial and temporal uncertainties associated with atmospheric deposition fluxes estimated in this study. 相似文献
10.