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X. Bai T.K. Gaisser A. Karle K. Rawlins G.M. Spiczak Todor Stanev 《Astroparticle Physics》2006,25(6):361-367
The muon flux at the South Pole was measured for five zenith angles, 0°, 15°, 35°, 82.13° and 85.15° with a scintillator muon telescope incorporating ice Cherenkov tank detectors as the absorber. We compare the measurements with other data and with calculations. 相似文献
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Todor Ganev Fumio Yamazaki Tsuneo Katayama Teruyuki Ueshima 《Soil Dynamics and Earthquake Engineering》1997,16(7-8):459-470
This paper presents results from forced vibration tests, microtremor observations and earthquake response analysis of a nuclear reactor containment model constructed on stiff soil in Hualien, Taiwan. The dynamic behavior of the soil-structure system is simulated successfully with two numerical models: a sway-rocking model, whose soil parameters are evaluated on the basis of the continuum formulation method, and a finite element model, using the program SASSI with the flexible volume substructuring approach. The dependences of the soil parameters of both models on the amplitudes of the different dynamic excitations are investigated in detail. An original numerical simulation of microtremor is performed. Comparison with results of a previous study involving a rigid tower on a soft soil site in Chiba, Japan is offered. 相似文献
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Sokrat Amataj Todor Anovski Ralf Benischke Romeo Eftimi Laurence L. Gourcy Liliana Kola Ioannis Leontiadis Eftim Micevski Alqiviadis Stamos Jovan Zoto 《Environmental Geology》2007,51(5):749-753
Prespa Lake and Ohrid Lake constitute a hydraulic system shared between Albania, FYR of Macedonia and Greece. Karst rocks
separate both lakes. The elevation of Prespa Lake is about 150 m higher than that of Ohrid Lake. Considering these facts,
Cvijić formulated in 1906 the hypothesis that Prespa Lake recharges the St. Naum and Tushemisht springs at Ohrid lakeside.
Environmental isotopes demonstrated that Prespa Lake recharges about 37–42 and 52–54% of water emerging in St. Naum, and Tushemisht
springs, respectively. An artificial tracer experiment carried out in 2002 physically demonstrated the underground connection
between both lakes. This experiment confirmed the supposed underground connection and brought important information about
the groundwater velocity, transit time, and karst water conduits development. 相似文献
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Todor Todorov 《地学学报》1991,3(3):311-316
Minerals from deposits Chelopech, Elshitsa, Radka and Krasen have been studied and their gold contents determined by neutron-activation. In all deposits sulphide and sulphosalt minerals show a well-expressed ability to concentrate gold, although their role in individual deposits is not equal. The highest concentration of gold is in bornite, tennantite, enargite and the early generations of pyrite, chalcopyrite, galena and sphalerite. The low content of gold in the late generations of pyrite, chalcopyrite, galena and sphalerite is due to the process of recrystallization and redeposition. The data obtained show that gold has been extracted entirely from the solutions of the early quartz-pyrite stage mineralizations while during the later quartz-sulphosalt-sulphide and quartz-carbonite-sulphate stages it was only re-deposited and concentrated. 相似文献
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This paper presents results of observation and analysis of the response of one of the longest cable-stayed bridges in the world to the Hyogoken–Nanbu (Kobe) Earthquake of 17 January 1995. It is determined that interaction of the foundations of the bridge towers with the supporting soil plays a decisive role in the overall structural behaviour. The key factor governing the changes of the soil properties at this site is pore-water pressure buildup, which results in liquefaction of the saturated surface soil layers under large dynamic loads. Models of the soil and structure are created and initially validated by accurately simulating the system response to a small earthquake. Soil parameters reflecting the pore-water pressure buildup in the strong earthquake are determined by an advanced non-linear effective stress analysis, combining the Ramberg–Osgood model of stress–strain dependence with a pore pressure model based on shear work concept. They are utilized to investigate and simulate the interaction of the foundation and the supporting soil using the program SASSI with the flexible volume substructuring approach. The results show a good agreement with the observations and have useful implications to the scientific and engineering practice. © 1998 John Wiley & Sons, Ltd. 相似文献
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Peter Nojarov Ivo Kalapov Jordan Stamenov Todor Arsov 《Theoretical and Applied Climatology》2014,115(3-4):471-482
Some connections between aerosols, atmospheric transport, and relative humidity are investigated based on measurements at Basic Environmental Observatory (BEO) station, peak Musala (2,925 masl) for the period January 2009–January 2010. Data are chosen at 0:00 and 12:00 GMT every day. Main methods employed in this research are statistical—nonparametric tests of Mann–Whitney and Spearman. The main conclusion is that greater aerosol load at peak Musala is connected with transport of air masses from north to east horizon quarters. Bigger particles with longer lifetimes come from there. Air coming from the south horizon quarter is aerosol clearer. Relative humidity shows opposite distribution—higher values for transport from south horizon quarter. Correlation between this parameter and aerosols is negative with significant but small value. Distribution of blue, green, and red scattering and backscattering coefficients is similar to distribution of total aerosol concentration. Correlations between scattering and backscattering coefficients and total aerosol concentration are significant and positive. Courses of total aerosol concentration; diameter of particles with maximum concentration; and blue, green, and red scattering and backscattering coefficients have summer maximum and winter minimum. Diurnal course of total aerosol concentration in the two main seasons, winter (January) and summer (July), has day maximum and night minimum. Aerosols at peak Musala are predominantly of transparent or translucent type. The calculation of Ångström exponent α is more precise by using scattering coefficients. The nephelometers data could successfully characterize the haziness of the atmosphere above peak Musala. 相似文献
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A vast amount of earthquake response records of an observation tower are used together with microtremor data to investigate various aspects of the dynamic behaviour of the soil-structure system. It is found that separation of the soil from the structure occurs under large dynamic loads, leading to changes in the predominant frequency of the system. As a result of the decreasing of the soil support at the side walls of the foundation, the stress caused by the structural weight on the bottom soil increases during earthquakes. With regard to its practical applicability, a linear sway-rocking model is applied for numerical modelling of the soil-structure system. Alterations in the soil support as a result of soil non-linearity and separation of the structure from the soil are investigated by comparing recorded and simulated structural response. The influence of each of these factors on the softening of the soil support is distinctly assessed. An empirical relationship between the peak ground velocity and the soil constants for earthquake excitations of different magnitude is presented. 相似文献
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Angelina Todorova Dimiter Syrakov Georgi Gadjhev Georgi Georgiev Kostadin G. Ganev Maria Prodanova Nikolai Miloshev Valery Spiridonov Andrej Bogatchev Kiril Slavov 《Earth Science Informatics》2010,3(4):259-282
Three Grid applications from the SEE-GRID-SCI Environmental VO are developed by the Bulgarian project team: Climate Change
Impact on Air Quality (CCIAQ); Multi-scale atmospheric composition modeling (MSACM); Modeling System for Emergency Response
to the Release of Harmful Substances in the Atmosphere (MSERRHSA). The three applications concern problems of significant
socio-economic significance. They are all dedicated to air pollution studies, but address different goals and so face different
problems and requirements. The applications are briefly presented in the paper. Examples of the different applications validations
are given. Some application results are shown and commented. 相似文献
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Emanouil Atanassov Aneta Karaivanova Todor Gurov Sofiya Ivanovska Mariya Durchova Dimitar Sl. Dimitrov 《Earth Science Informatics》2010,3(4):289-296
In this paper we present error and performance analysis of quasi-Monte Carlo algorithms for solving multidimensional integrals
(up to 100 dimensions) on the grid using MPI. We take into account the fact that the Grid is a potentially heterogeneous computing
environment, where the user does not know the specifics of the target architecture. Therefore parallel algorithms should be
able to adapt to this heterogeneity, providing automated load-balancing. Monte Carlo algorithms can be tailored to such environments,
provided parallel pseudorandom number generators are available. The use of quasi-Monte Carlo algorithms poses more difficulties.
In both cases the efficient implementation of the algorithms depends on the functionality of the corresponding packages for
generating pseudorandom or quasirandom numbers. We propose efficient parallel implementation of the Sobol sequence for a grid
environment and we demonstrate numerical experiments on a heterogeneous grid. To achieve high parallel efficiency we use a
newly developed special grid service called Job Track Service which provides efficient management of available computing resources through reservations. 相似文献