Dynamics of inelastic base‐isolated structures subjected to analytical pulse ground motions     

Michalis F. Vassiliou  Anastasios Tsiavos  Božidar Stojadinović 《地震工程与结构动力学》2013,42(14):2043-2060

Structural design code provisions worldwide prescribe relatively small seismic force reduction factors for seismically base‐isolated structures, making their response to design‐level earthquake excitation essentially elastic. This paper uses the method of dimensional analysis to prove that; in most cases, this is not a conservative design approach but a necessity that emerges from the dynamics of base‐isolated structures. It is shown that allowing typical base‐isolated structures to yield results in large displacement ductility demands for the structure. This phenomenon is caused by the change in the nature of the ground motion excitation as it is transmitted to the structure through the seismic base isolation system as well as by the change in the distribution of displacements between the structure and the isolation bearings caused by yielding of the isolated structure. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Photocatalytic Degradation of Dye C.I. Direct Blue 78 Using TiO2 Nanoparticles Immobilized on Recycled Wool‐Based Nonwoven Material     

Darka Marković  Bojan Jokić  Zoran Šaponjić  Branislav Potkonjak  Petar Jovančić  Maja Radetić 《洁净——土壤、空气、水》2013,41(10):1002-1009

This paper discusses the possibility of immobilization of TiO₂ nanoparticles onto recycled wool‐based nonwoven material, which can be utilized for removal of dyes from wastewater. The photocatalytic activity of TiO₂ nanoparticles deposited on the nonwoven material was evaluated in the aqueous solution of direct dye C.I. Direct Blue 78 under the UV illumination. Nonwoven material modified with TiO₂ nanoparticles provides complete removal of dye from the solution already after 4–6 h of UV illumination. However, photodegradation of the dye adsorbed on the nonwoven material was obtained within 24 h of UV illumination. The rate of dye adsorption and photodegradation depends on the amount of deposited TiO₂ nanoparticles. The increase of initial dye concentration induced decrease in photocatalytic efficiency of immobilized TiO₂ nanoparticles. The highest photodegradation rate was achieved in acidic conditions. Elevated temperatures positively affected the removal of dye from solution. Photocatalytic activity of TiO₂ nanoparticles deposited on nonwoven material was preserved after three photodegradation cycles.  相似文献   

The Energy of High-Frequency Waves in the Low Solar Chromosphere     

A. Anđić 《Solar physics》2007,242(1-2):9-20

High-frequency acoustic waves have been suggested as a source of mechanical heating in the chromosphere. In this work the radial component of waves in the frequency interval 22 to 1 mHz are investigated. Observations were performed using 2D spectroscopy in the spectral lines of Fe i 543.45 nm and Fe i 543.29 nm at the Vacuum Tower Telescope, Tenerife, Spain. Speckle reconstruction has been applied to the observations. We have used Fourier and wavelet techniques to identify oscillatory power. The energy flux is estimated by assuming that all observed oscillations are acoustic running waves. We find that the estimated energy flux is not sufficient to cover the chromospheric radiative losses.  相似文献   

Spatial patterns and drivers of fire occurrence in a Mediterranean environment: a case study of southern Croatia     

Katarina Pavlek  Filip Bišćević  Petra Furčić  Ana Grđan  Vesna Gugić  Nino Malešić 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2017,117(1):22-35

Wildfires are an important factor of landscape dynamics in fire-prone environments of the world. In the Mediterranean, one of the most fire-susceptible environments globally, between 45,000 and 50,000 wildfires are recorded every year, causing disturbances in forest and grassland ecosystems. As a Mediterranean country, Croatia faces these problems, averaging over 1000 registered wildfires annually, with the coastal areas dominated by forest fires and continental Croatia by fires on agricultural lands. This research combines various landscape and socio-economic factors in the analysis of fire occurrence in Croatia’s southernmost region of Dalmatia. Around 275 of the largest fires (encompassing 98% of the total burnt area) registered in 2013 were investigated using OLS, and different spatial indices were employed to analyse regional variability in fire distribution. The results revealed that areas more prone to fires are the northern inland areas of Dalmatia and its entire coastal zone. Altitude and vegetation type demonstrated a correlation with fire occurrence, but an increase in population in the study area was also correlated with wildfire occurrence. Regarding vegetation, the grasslands and Mediterranean shrubland (maquis) were found to be the most fire-prone vegetation types in the study region, the distribution of which can be linked to different socio-economic and demographic processes occurring in the Eastern Adriatic.  相似文献   

Circulation weather types and their influence on precipitation in Serbia     

Suzana Putniković  Ivana Tošić  Vladimir Đurđević 《Meteorology and Atmospheric Physics》2016,128(5):649-662

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The acid–base,morphological and structural properties of new biosorbent obtained by oxidative hydrothermal treatment of peat     

M. Ranđelović  M. Momčilović  M. Purenović  A. Zarubica  A. Bojić 《Environmental Earth Sciences》2016,75(9):764

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A comparative study for estimation of wave height using traditional and hybrid soft-computing methods     

Chandrabhushan Roy  Shervin Motamedi  Roslan Hashim  Shahaboddin Shamshirband  Dalibor Petković 《Environmental Earth Sciences》2016,75(7):590

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Multi-methodological approach to evaluate trace elements and major components in wetland system with subsaline and freshwater characteristics     

Vlado Cuculić  Stanislav Frančišković-Bilinski  Halka Bilinski  Krešimir Maldini  Damir Tomas  Nenad Tomašić 《Environmental Earth Sciences》2016,75(20):1351

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Response of microorganisms and enzymes to soil contamination with a mixture of pethoxamid terbuthylazine     

Jadwiga Wyszkowska  Monika Tomkiel  Małgorzata Baćmaga  Agata Borowik  Jan Kucharski 《Environmental Earth Sciences》2016,75(18):1285

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The case of Bougainvillia triestina Hartlaub 1911 (Hydrozoa,Cnidaria): a 100‐year‐long struggle for recognition          下载免费PDF全文

Mirna Batistić  Rade Garić 《Marine Ecology》2016,37(1):145-154

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