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排序方式: 共有56条查询结果,搜索用时 31 毫秒
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.
A. Piccioni F. Giovanelli K. Bartolini I. Bruni M. Frutti A. Guarnieri 《Astronomy Reports》2002,46(12):1030-1041
The structure of the electronics of the two-head, high-speed photometer operating on the 152-cm G.D. Cassini telescope of Bologna University has been fully redesigned for high-time-resolution observations of fast variable sources, in particular, of the optical counterparts of X-ray binary systems. The fast photometer now permits sampling times from 0.1 ms to 100 s. The handling of the system clock and I/O configuration have been modified to provide rigorous synchronization of the sampling time with an external high-stability clock and the continuous acquisition of an uninterrupted data stream. The continuous data-acquisition process, which is driven by an external clock, is limited only by the capacity of the hard disk and is supported by a double-buffer SRAM memory designed to overcome any discontinuity in the asynchronous communication with the computer. Real-time monitoring of the data enables continuous evaluation of the weather conditions, and the directly displayed light curve can be used to determine the optimal management of the observations. 相似文献
3.
Prediction of ground vibration due to quarry blasting based on gene expression programming: a new model for peak particle velocity prediction 总被引:1,自引:1,他引:0
R Shirani Faradonbeh D Jahed Armaghani M. Z. Abd Majid M. MD Tahir B. Ramesh Murlidhar M. Monjezi H. M. Wong 《International Journal of Environmental Science and Technology》2016,13(6):1453-1464
Blasting is a widely used technique for rock fragmentation in opencast mines and tunneling projects. Ground vibration is one of the most environmental effects produced by blasting operation. Therefore, the proper prediction of blast-induced ground vibrations is essential to identify safety area of blasting. This paper presents a predictive model based on gene expression programming (GEP) for estimating ground vibration produced by blasting operations conducted in a granite quarry, Malaysia. To achieve this aim, a total number of 102 blasting operations were investigated and relevant blasting parameters were measured. Furthermore, the most influential parameters on ground vibration, i.e., burden-to-spacing ratio, hole depth, stemming, powder factor, maximum charge per delay, and the distance from the blast face were considered and utilized to construct the GEP model. In order to show the capability of GEP model in estimating ground vibration, nonlinear multiple regression (NLMR) technique was also performed using the same datasets. The results demonstrated that the proposed model is able to predict blast-induced ground vibration more accurately than other developed technique. Coefficient of determination values of 0.914 and 0.874 for training and testing datasets of GEP model, respectively show superiority of this model in predicting ground vibration, while these values were obtained as 0.829 and 0.790 for NLMR model. 相似文献
4.
G. Beskin S. Karpov S. Bondar A. Guarnieri C. Bartolini D. Greco A. Piccioni 《Astrophysical Bulletin》2010,65(3):223-229
The results of observations of the optical emission that accompanied the gamma-ray burst GRB 080319B are reported. Observations
were made using the TORTORA fast wide-field camera mounted on the REM robotic telescope in Chile. The behavior of the light
curve before, during, and after the gamma-ray burst is described. The light curve consists of four, possibly periodic, 5–7
s long peaks 8–9 s apart. The behavior of the burst in the gamma and optical energy ranges are compared and the results of
the theoretical interpretation of this comparison are reported. 相似文献
5.
A hydrometric, hydrochemical and environmental isotopic study was conducted to identify the source and origin of observed springs on the foot of the hillock abutting the left flank of the Gollaleru earthen dam, Nandyal, Andhra Pradesh, India. Water samples (springs, reservoir water and groundwater) in and around the dam area were collected and analyzed for environmental isotopes (\(\updelta ^{18}\!\hbox {O}\), \(\updelta ^{2}\hbox {H}\) and \(^{3}\hbox {H}\)) and hydrochemistry. Reservoir level, spring discharges and physico-chemical parameters (temperature, electrical conductivity, pH, etc.) were monitored in-situ. Isotopic results indicated that the source of springs is from the Owk reservoir and groundwater contribution to the springs is insignificant. Based on hydrometric observations, it is inferred that the springs might be originated from the reservoir level of 209 m amsl. It is found that the lower spring discharges were derived from diffuse sources (seepage) which could be a mixture of reservoir water and the groundwater, while the relatively higher spring discharges were resulted from concentrated sources (leakage) from the reservoir. Thus, the study portraits the usefulness of isotope techniques in understanding the dam seepage/leakage related problems. 相似文献
6.
Spatial and temporal dust source variability in northern China identified using advanced remote sensing analysis 总被引:1,自引:0,他引:1
A. Taramelli M. Pasqui J. Barbour D. Kirschbaum L. Bottai C. Busillo F. Calastrini F. Guarnieri C. Small 《地球表面变化过程与地形》2013,38(8):793-809
The aim of this research is to provide a detailed characterization of spatial patterns and temporal trends in the regional and local dust source areas within the desert of the Alashan Prefecture (Inner Mongolia, China). This problem was approached through multi‐scale remote sensing analysis of vegetation changes. The primary requirements for this regional analysis are high spatial and spectral resolution data, accurate spectral calibration and good temporal resolution with a suitable temporal baseline. Landsat analysis and field validation along with the low spatial resolution classifications from MODIS and AVHRR are combined to provide a reliable characterization of the different potential dust‐producing sources. The representation of intra‐annual and inter‐annual Normalized Difference Vegetation Index (NDVI) trend to assess land cover discrimination for mapping potential dust source using MODIS and AVHRR at larger scale is enhanced by Landsat Spectral Mixing Analysis (SMA). The combined methodology is to determine the extent to which Landsat can distinguish important soils types in order to better understand how soil reflectance behaves at seasonal and inter‐annual timescales. As a final result mapping soil surface properties using SMA is representative of responses of different land and soil cover previously identified by NDVI trend. The results could be used in dust emission models even if they are not reflecting aggregate formation, soil stability or particle coatings showing to be critical for accurately represent dust source over different regional and local emitting areas. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
7.
8.
C K CHANG H MD AZAMATHULLA N A ZAKARIA A AB GHANI 《Journal of Earth System Science》2012,121(1):125-133
This paper evaluates the performance of three soft computing techniques, namely Gene-Expression Programming (GEP) (Zakaria
et al 2010), Feed Forward Neural Networks (FFNN) (Ab Ghani et al 2011), and Adaptive Neuro-Fuzzy Inference System (ANFIS) in the prediction of total bed material load for three Malaysian
rivers namely Kurau, Langat and Muda. The results of present study are very promising: FFNN (R
2 = 0.958, RMSE = 0.0698), ANFIS (R
2 = 0.648, RMSE = 6.654), and GEP (R
2 = 0.97, RMSE = 0.057), which support the use of these intelligent techniques in the prediction of sediment loads in tropical
rivers. 相似文献
9.
This article presents a methodology for designing a WebGIS framework intended for automatically analyzing spatial data and updating statistics of interest with new information inserted daily by multiple users via a Web portal. A practical example is used on vehicle accident data for assessing risk in specific road segments. Two main blocks integrated together will be described: the collaborative block and the data‐analysis block. The former gives end‐users computer‐aided tools to view, insert, modify and manage data related to accidents and traffic monitoring sensors, whereas the latter is developed to automatically analyze the accident data coming from user's collaboration. Because different agencies can survey accident sites, a collaborative environment is necessary – and a Web‐based solution is ideal – for permitting multi‐user access and data insertion. A centralized approach to process the data in real time is described in all its components. Server‐side Structured Query Language functions optimize performance by using dedicated libraries for spatial processing and re‐structuring the attributes associated with elements which are consequently re‐classified for correct color‐scaling. The end‐product is a system that provides a seamless integration of front‐end tools for user collaboration and back‐end tools to update accident risk statistics in real time and provide them to stakeholders. 相似文献
10.
E. Echer B.T. Tsurutani F.L Guarnieri J.U. Kozyra 《Journal of Atmospheric and Solar》2011,73(11-12):1330-1338
The seven CAWSES interplanetary fast forward shocks and their geomagnetic effects during 2004–2005 have been analyzed. It is found that the arrival time of the shocks at Earth can be estimated within an accuracy of ~5 min. Furthermore, AL decreases are found to occur within 10 min of shock impingement on the magnetopause. It was also determined that there is a direct correlation between the interplanetary magnetic field southward directed (IMF Bs) prior to shock arrival and substorms triggered by the shocks. If the IMF is northward prior to shock arrival, the geomagnetic activity is present but is low. One interpretation of this result is that the preconditioning energy stored in the magnetotail leaks away rapidly. A correlation between substorm peak AL and shock strength (Mach number) has also been noted, which could imply that shock strength is important for the amount of energy released into the magnetosphere/ionosphere. 相似文献