Behaviour of steel cushions subjected to combined actions     

Ercan Yüksel  Faruk Karadoğan  Hasan Özkaynak  Arastoo Khajehdehi  Ahmet Güllü  Eleni Smyrou  İhsan Engin Bal 《Bulletin of Earthquake Engineering》2018,16(2):707-729

Mild steel is relatively low-cost and easily accessible material to fabricate some structural members. It would be a significant advantage if seismic energy dissipaters that are used in structures constructed in the earthquake prone areas, could also be produced on site. In this paper, a promising seismic energy dissipater made of mild steel, so-called steel cushion (SC) is presented. It is provided experimental and analytical responses of SCs subjected to bi-axial loadings. SC rolls under the lateral loading that allows relocation of the plasticized cross-section. Henceforth, SC dissipates considerable amount of seismic energy. A series of tests were performed to achieve experimentally the behavior of SC subjected to longitudinal and transversal loading. Finite Element Models (FEMs) were also generated to reproduce the experimental backbone curves and to predict the bi-directional response properties for discrete transversal forces and plate thicknesses. Closed-form equations were derived to determine yield and ultimate forces and the corresponding displacements as well as location of the plasticized sections. The behavior of SC could either be projected by the FEMs with the exhibited parameters or by means of the proposed closed-form equations and the normalized design chart.  相似文献   

Correction to: Nexus between vulnerability and adaptive capacity of drought-prone rural households in northern Bangladesh     

Salam  Roquia  Islam  Abu Reza Md. Towfiqul  Shill  Badhon Kumar  Alam  G. M. Monirul  Hasanuzzaman  Md.  Hasan  Md. Morshadul  Ibrahim  Sobhy M.  Shouse  Roger C. 《Natural Hazards》2021,106(1):529-529

Natural Hazards - The article was published with a spelling error in one of the co-author names. The correct spelling is reflected in this correction, and the original work has been updated to...  相似文献   

Effects of solution mining on groundwater quality in the Kazan trona field,Ankara-Turkey: model predictions     

Hasan Yazicigil  Cevat Er  Jale Sakiyan Ates  M. Zeki Camur 《Environmental Geology》2009,57(1):157-172

Three aquifer systems as deep, middle, and shallow were identified in the Kazan trona ore deposit area. The flow conditions and the interaction between various layers were conceptualized into a site hydrogeological model. Each aquifer system was hydraulically and chemically characterized and represented in a numerical groundwater model. The resulting model has been calibrated under steady-state and transient conditions using available data. The flow model was used in conjunction with a three-dimensional solute transport model to assess the impacts of the pilot well solution mining of the trona deposit on groundwater resources during operation and post-operation periods. The results of operation period indicate that, even under the worse conditions (50 times increase in vertical hydraulic conductivity due to subsidence), ion contribution from the mine area with 118,000 mg/l maximum concentration would be about 58 mg/l into the deep aquifer system. This contribution is about 1.45% of the existing concentration (4,000 mg/l) in the deep aquifer. After 1,000 years of post-operation period, ion contribution from the mine area with maximum 119,000 mg/l concentration would be about 205 mg/l into the deep aquifer under extremely worse conditions. This contribution is about 5–20% of present concentrations in the deep aquifer. Retardation factors, which were not considered during model simulations would decrease the predicted concentrations. It is concluded that pilot well solution mining of the trona deposit would not have significant impact on the quality of groundwater resources in the overlying aquifers.  相似文献   

Sustainable management of Mogan and Eymir Lakes in Central Turkey   总被引：2，自引：0，他引：2  

Ozlem Yagbasan  Hasan Yazicigil 《Environmental Geology》2009,56(6):1029-1040

Mogan and Eymir Lakes, located 20 km south of Ankara in Central Turkey, are important aesthetic, recreational, and ecological resources. Dikilitas and Ikizce reservoirs, constructed on upstream surface waters, are two man-made structures in the basin encompassing an area of 985 km². The purpose of this study is to quantify groundwater components in lakes’ budgets and to assess the potential impacts of upstream reservoirs on lake levels for sustainable management of the system. Available data have been used to develop a conceptual model of the system. A three-dimensional groundwater model, incorporating a lake component, has been developed for the system. The model has been calibrated successfully under transient conditions over a period of 6 years using monthly periods. The results show that groundwater inflows and outflows have the lowest contribution to the overall lakes’ budget. The model has been subsequently used to evaluate the impacts of upstream reservoirs. The results show that these reservoirs have a significant effect on lake stages but not on groundwater levels. A trade-off curve between the quantum of water released and the average stage in Lake Mogan has been developed to enhance decision makers’ ability for sustainable management of the system in the long term.  相似文献   

Quantitative analysis of physical and geotechnical factors affecting methane emission in municipal solid waste landfill   总被引：1，自引：0，他引：1  

Dawit Tecle  Jejung Lee  Syed Hasan 《Environmental Geology》2009,56(6):1135-1143

The amount of methane that vent from landfills is dependent on the physical, chemical and biological components of the soil cover. Especially moisture content and temperature of the soil are known as the major controlling factors. In situ moisture content measurement is very critical because the moisture content of the soil continuously changes within minutes to hours as a result of change in temperature. The presented study used time domain reflectometry to measure in situ moisture content and analyzed moisture content, temperature and methane data of the landfill soil cover in a quantitative manner. Geotechnical factors including soil grain size and uniformity coefficient of the soil were analyzed and their influence on moisture content and methane emission was examined. The authors used kriging and polynomial regression methods to characterize the spatial distribution of moisture content and methane emission. Methane emission showed good temporal correlation with soil temperature, however, no significant relationship between moisture content and methane emission was observed. Spatial distribution of soil attributes was also analyzed to examine its effect on those variables. The spatial pattern of moisture content was quite similar to that of uniformity coefficient, C _u and that of clay content of the soil but strongly contrasted to that of methane emission.  相似文献   

Remote sensing of aerosols over the Solar Village, Saudi Arabia     

I. Sabbah  Fatma M. Hasan 《Atmospheric Research》2008,90(2-4):170-ICNAA07

Aerosol optical properties over Solar Village, Saudi Arabia have been studied using ground-based remote sensing observations through the Aerosol Robotic Network (AERONET). Our analysis covered 8 recorded years of aerosol measurements, starting from February 1999 through January 2007. The seasonal mean values of aerosol optical thickness (AOT), the Ångström wavelength exponent α and the surface wind speed (V), exhibit a one year cyclical pattern. Seasonal variations are clearly found in the shape and magnitude of the volume size distribution (VSD) of the coarse size mode due to dust emission. The Spring is characterized by dusty aerosols as the modal value of the exponent α was low ~ 0.25 while that of AOT was high ~ 0.3. The modal value of wind speed was the highest ~ 3.6 m/s in spring. The increase in wind speed is responsible for increasing the concentration of dust particles during Spring. Spring of 2003 has the highest mean values of AOT, V and VSD and the lowest mean value for the exponent α. The seasonal mean values of the exponent α are anticorrelated with those of the wind speed (r = − 0.63). The annual mean values of the exponent α are well correlated (r = 0.77) with those of the difference between the maximum and minimum values of temperature ΔT. They are anticorrelated (r = − 0.74) with the annual mean values of the relative humidity. Large aerosol particles and high relative humidity increase the radiative forcing. This results in reduction of the values of the temperature difference ΔT.  相似文献   

A new software on TUG-T60 autonomous telescope for astronomical transient events     

Murat Dindar  Selçuk Helhel  Hasan Esenoğlu  Murat Parmaksızoğlu 《Experimental Astronomy》2015,39(1):21-28

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An algorithm for the optimum design of braced and unbraced steel frames under earthquake loading     

Gülten Gülay  Hasan Bodurolu 《地震工程与结构动力学》1989,18(1):121-128

A solution technique based on the sequential linear programming (SLP) method is presented for the optimum design of braced and unbraced steel frames in seismic regions. First, the optimum rigidity distribution of the frames under static loading is computed, then the optimization procedure is repeated under the combined loading, setting lower bounds on the optimum static cross-sectional areas and increasing allowable stresses. The stiffness, stress, displacement and side constraints are included in the optimization problem. As a result, a highly non-linear mathematical programming problem is produced. A non-linear programming algorithm is offered for the solution which is based on the successive linearization of non-linear expressions and employs the simplex routine in an iterative manner. Design variables are chosen to be the free nodal displacements and the cross-sectional areas of the members, while the objective function is taken to be the minimization of the total volume of the structure. As numerical applications, optimum weights of several frames (unbraced, concentrically and eccentrically braced) under static and combined loading cases are computed and the results are compared with those available in the literature.  相似文献   

Comment on “Update on terrestrial ages of Antarctic meteorites” by K. Nishiizumi, D. Elmore and P.W. Kubik     

Derek W.G. Sears  Fouad A. Hasan  Benjamin M. Myers  Hazel Sears 《Earth and Planetary Science Letters》1990,99(4)

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Prediction of climate change in Brunei Darussalam using statistical downscaling model     

Hasan  Dk. Siti Nurul Ain binti Pg. Ali  Ratnayake  Uditha  Shams  Shahriar  Nayan  Zuliana Binti Hj  Rahman  Ena Kartina Abdul 《Theoretical and Applied Climatology》2018,133(1-2):343-360

Theoretical and Applied Climatology - Climate is changing and evidence suggests that the impact of climate change would influence our everyday lives, including agriculture, built environment,...  相似文献