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This work accounts for an investigation about the diurnal variation of total spectral transmittance of solar irradiance under dominant wind conditions as case studies. Such a work is carried out in Athens for the first time. The spectral transmittance values estimated were derived using ground-based spectral measurements of beam irradiance in the range 310–575 nm (UV and VIS). The data were recorded by a system consisting of an automatic solar tracker and a spectrometer. All data were recorded under clear-sky conditions in the city center of Athens and the spectral total atmospheric transmittance was estimated towards zenith to avoid optical mass effects. The comparison reveals that the total atmospheric transmittance is higher under the influence of strong Etesian compared to sea-breeze conditions. The influence of low-pressure systems also plays a depollution role in the basin. Various features of diurnal variation are discussed with respect to emission sources, topographic peculiarities and wind pattern. 相似文献
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A methodology for the probabilistic analysis of reinforced concrete cantilever walls is developed and described in this paper. The wall’s external stability under static conditions is addressed and modeled as a series system with correlated failure modes. Computations of reliability are performed using Monte Carlo simulations for assumed probability distributions of the backfill and foundation material engineering properties. A case example is analyzed based on the described methodology. The results indicated that risk, measured by the system probability of failure, is not a linear function of safety ratios. All three safety ratios in question were positively correlated, with bearing capacity being subjected to higher degree of uncertainty. The degree of correlation was found to have an important effect on the system probability of failure. Considering the width of the base as varying design parameter, the study also showed that first-order reliability bounds, which are often applied in practice, may lead to a noteworthy over- or under-estimation of the design. 相似文献
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Deliveris Alexandros V. Zevgolis Ioannis E. Koukouzas Nikolaos C. 《Geotechnical and Geological Engineering》2021,39(6):4491-4510
Geotechnical and Geological Engineering - A reliability analysis framework for the stochastic simulation of slope progressive failure is proposed in the current work. Progressive failure is... 相似文献
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A. D.?Adamopoulos H. D.?KambezidisEmail author D.?Zevgolis 《Pure and Applied Geophysics》2005,162(2):409-431
This work investigates the seasonal and diurnal variation of total spectral transmittance of solar radiation. Such a study dealing with ultraviolet and visible wavelengths (310–575 nm) is carried out in Athens for the first time. The spectral values presented are averages over a number of records in a period of 42 days and have been calculated using ground-based spectral measurements of direct-beam irradiance. The data were recorded on selected days throughout a year by a simple pyrheliometer capable of performing spectral measurements. All data were recorded under clear-sky conditions in the city center of Athens and the total spectral atmospheric transmittance was estimated in the direction of local zenith to become independent of any optical mass effects. The comparison between seasons reveals that the atmospheric transmittance is higher in the cold period of the year than in the warm, simply because the photochemical pollution in the summer is more severe. Various features of seasonal and diurnal variation are also discussed with respect to emission sources, topographic peculiarities and wind regime. 相似文献
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Al Heib Marwan Zevgolis Ioannis E. Theocharis Alexandros I. Koukouzas Nikolaos C. Coccia Stella 《Geotechnical and Geological Engineering》2022,40(3):1307-1321
Geotechnical and Geological Engineering - Mining operations can drastically affect the stability of nearby areas. A representative case for this has been the Mavropigi mine, a part of an open-pit... 相似文献
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Deliveris Alexandros V. Theocharis Alexandros I. Koukouzas Nikolaos C. Zevgolis Ioannis E. 《Geotechnical and Geological Engineering》2022,40(8):4023-4039
Geotechnical and Geological Engineering - Rainfall leads to the deterioration of slope stability conditions, while intense rainfall has been commonly associated with landslides on natural or... 相似文献
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—?This work estimates the Ångström coefficients, assuming a linear behavior of the natural logarithm of aerosol optical thickness, ln δα(λ), versus the natural logarithm of wavelength, ln λ, in the urban environment of Athens for a period of one year. The calculation of the coefficients α, β, was carried out using records of spectral beam irradiance in the 320–575?nm spectral range. The seasonal and diurnal variation of the coefficients shows different features with generally higher values of β and lower values of α in summertime. The Ångström coefficients are investigated with respect to various wind regimes and the results are discussed with a view to air pollution sources, climatic and topographic characteristics of the Athens basin. A similar study is also carried out for the Schüepp's turbidity parameter. 相似文献
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H. D.?KambezidisEmail author A. D.?Adamopoulos D.?Zevgolis 《Pure and Applied Geophysics》2005,162(3):625-647
This work investigates the spectral atmospheric transmittance due to aerosols in the urban environment of Athens during a period of one year. The spectral transmittance due to aerosols is derived using measurements of spectral direct-beam solar irradiance in the 310–575 nm spectral band. This derivation is accomplished by using a radiative transfer model for estimating the partial spectral atmospheric transmittance functions due to Rayleigh scattering, and absorption by ozone, nitrogen dioxide and water vapor. The seasonal and diurnal variation of the aerosol transmittance is investigated and the results are discussed with a view to air pollution sources, meteorological factors and topographic characteristics of the Athens basin. 相似文献
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