排序方式： 共有25条查询结果，搜索用时 31 毫秒
1.
A. Tirgar MSPH. F. Golbabaei MSPH. Ph.D. J. Hamedi Ph.D. K. Nourijelyani MSPH. Ph.D. S. J. Shahtaheri MSPH. Ph.D. S. R. Moosavi M.Sc. 《International Journal of Environmental Science and Technology》2006,3(3):305-313
Airborne hexavalent chromium is a known human respiratory carcinogen and allergen. Many workers are exposed to hexavalent chromium in various processes which chromium electroplating plants are the most common. In this study, the feasibility of a new control approach to remove this pollutant using chitosan beads as a biosorbent was investigated. Hexavalent chromium sorption was studied relative to pH, pollution concentration, sorbent concentration, temperature, and air velocity using one factor at a time approach and Taguchi experimental design. Polluted air with different chromium mist concentrations (10–5000 μg/m3) was contacted to chitosan beads (3.3–20 g/L), floating in distilled water with adjusted pH (3–7), using an impinger at different temperatures (20 and 35 °C), and various velocities (1.12 and 2.24 m/s). The ANOVA test result showed that, there were statistical significant differences between factor levels except optimized pH levels. The higher ions removal efficiencies were achieved at lower levels of air velocities, pollution concentrations, and higher levels of solution pH values, temperatures, and sorbent concentrations. 相似文献
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The stochastic nature of the cyclic swelling behavior of mudrock and its dependence on a large number of interdependent parameters was modeled using Time Delay Neural Networks (TDNNs). This method has facilitated predicting cyclic swelling pressure with an acceptable level of accuracy where developing a general mathematical model is almost impossible. A number of total pressure cells between shotcrete and concrete walls of the powerhouse cavern at Masjed–Soleiman Hydroelectric Powerhouse Project, South of Iran, where mudrock outcrops, confirmed a cyclic swelling pressure on the lining since 1999. In several locations, small cracks are generated which has raised doubts about long term stability of the powerhouse structure. This necessitated a study for predicting future swelling pressure. Considering the complexity of the interdependent parameters in this problem, TDNNs proved to be a powerful tool. The results of this modeling are presented in this paper. 相似文献
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Climate change presents a threat to the sustainability of cities and their societies, and must be adequately addressed. Urban environments (cities) are responsible for the creation of a significant amount of greenhouse gas emissions which are the source of climate change. Cities have been increasingly the focus of action to address climate change, yet emissions are not significantly reducing. Additionally, there a lack of integration between adaptation and mitigation. This prevents responses adequate to limit global warming to 1.5OC, and to be well adapted to anticipated changes. This paper critically analyses existing definitions and typologies of climate change actions. A definition of ‘climate change transformation’ is proposed which includes the integration of adaptation and mitigation goals to enable a new regime in which global warming is limited to 1.5OC. A new three-part typology: ‘coping, malaction and transformation,’ is presented for categorising climate change actions by the extent to which they integrate adaptation and mitigation, and define a new regime. The typology is accompanied by illustrations to demonstrate the relationship between adaptation and mitigation. The definition, typology and illustration serve to guide effective climate change decision making, and provides principles to guide application in urban environments. 相似文献
4.
Alireza Talebinejad Hamid Chakeri Mahdi Moosavi Yılmaz Özçelik Bahtiyar Ünver Mehmet Ali Hindistan 《Arabian Journal of Geosciences》2014,7(9):3913-3923
Underground structures are currently widely used and are built as urbanism develops. The interactions between perpendicularly crossing and parallel tunnels in the Tehran region are investigated by using a full three-dimensional (3D) finite difference analysis with elastic-plastic material models. Special attention is paid to the effect of subsequent tunneling on the support system, i.e., the shotcrete lining and rock bolts of the existing tunnel. Eventually, as the tunnels are excavated at certain levels, the interaction between the tunnels will certainly have a significant influence on both stress distribution and consequently deformations. Since multilayer tunneling is a three-dimensional phenomenon in nature, 3D numerical solutions must be utilized for analyzing effect of perpendicularly crossing tunnels at various levels. As Tohid twin tunnels and Line 7 pass beneath the Line 4 metro tunnel, changes in stress distribution, deformations, and surface settlements are studied for various conditions and the results are presented in this paper. Consequently, it is shown that there is a significant interaction between tunnels that necessitate certain preventive measures to maintain a stable tunneling operation. 相似文献
5.
Moosavi Seyed Amin Bakhtiari Hesam Aloki Honarmand Javad 《Geotechnical and Geological Engineering》2022,40(6):3225-3244
Geotechnical and Geological Engineering - This study examined the petrographically classification, petrological and petrophysical characteristics by taking a vast range of carbonate reservoir rock... 相似文献
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S. Tayebi S. F. Moosavi S. A. Poorhashemi 《International Journal of Environmental Science and Technology》2017,14(7):1573-1582
Nowadays, two fundamental pillars of human existence are environmental protection and sustainable development. Governments and international organizations play an important role in this process. Without serious regional interactions and international cooperation, sustainability in development and environmental protection will not happen. Except for international interactions and global peace, sustainable development and development sustainability are not on their accurate paths. An effective method for natural resources and ecosystems conservation is environmental diplomacy. Therefore, environmental discussions are extremely important reasons for international convergence. Through convergence attitude, the international community can reach the global environmental conservation strategies. In this study, it is attempted to determine the international environmental law evolution and the governments’ roles in environmental challenges underlying the international convergence and legal fundamentals. It is concluded that, environmental threats and hazards resulted from illogical human act can be solved by international convergence, environmental conservation and global peace. 相似文献
7.
The Paleo-Tethys suture zone in northern Iran was formed when the Paleo-Tethys Ocean, (between Gonwana-derived Alborz Microcontinent and the Turan Plate), closed during the Eocimmerian orogeny and after they collided together in the Mid-Late Triassic. The NW-striking Boghrov-Dagh basement Fault Zone that lies in the vicinity of Masuleh village and the southern boundary of Gasht Metamorphic Complex is a part of the Eocimmerian suture zone in the Western Alborz. Along this part of the suture zone, tourmaline leucogranites intruded in metamorphic rocks. We recognize three distinct deformation stages (D1 to D3) in the study area especially in the Masuleh Shear Zone. D1 which was synchronous with formation of the main metamorphic minerals, such as sillimanite and staurolite under medium- to high-grade metamorphic conditions probably during the Hercynian event and a NE-directed shortening. The slaty cleavage in metamorphosed Upper Paleozoic rocks and crenulation cleavage and folds in the older rocks were produced due to D2 deformation during the Eocimmerian event under greenschist facies conditions. The Masuleh Shear Zone formed as a result of a ductile strike-slip shear during the Early-Middle Jurassic Mid-Cimmerian D3 event with a pure dextral to transtension shear sense at low to locally medium-grade conditions. All of the D3 structural features agree with a NNW-directed compression and an ENE-directed extension caused by overall dextral shear parallel to the Masuleh shear zone and the Boghrov-Dagh Fault Zone. Based on the available evidence, especially cross-cutting relationships between structural fabrics and rock units, emplacement of the Gasht-Masuleh leucogranites occurred after the D2 collisional event coeval to the possible slab break-off and before the D3 event, between Eocimmerian and Mid-Cimmerian movements. 相似文献
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In this paper, the effects of shear velocity on the shearing behavior of artificial joints have been studied at different normal stress levels. Here, artificial joints with planar and rough surfaces were prepared with the plaster (simulating soft rock joints) and concrete (medium-hard rock joints) materials. The rough joints had triangular shaped asperities with 10° and 20° inclination angles. Direct shear tests were performed on these joints under various shear velocities in the range of 0.3–30 mm/min. The planar plaster–plaster and planer concrete–concrete joints were sheared at three levels of normal stress under constant normal load boundary condition. Also, the rough plaster–plaster and concrete–concrete joints were sheared at one level of normal stress under constant normal stiffness boundary condition. The results of the shear tests show that the shearing parameters of joints, such as shear strength, shear stiffness and friction angle, are related to the shear velocity. Shear strength of planar and rough plaster–plaster joints were decreased when the shear velocity was increased. Shear strength of concrete joints, except for rough joints with 10° inclination, increased with increasing shear velocity. Regardless of the normal stress level, shear stiffness of both planar plaster–plaster and concrete–concrete joints were decreased when the shear velocity was increased. 相似文献
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Bagher Shirmohammadi Hamidreza Moradi Vahid Moosavi Majid Taie Semiromi Ali Zeinali 《Natural Hazards》2013,69(1):389-402
Drought is accounted as one of the most natural hazards. Studying on drought is important for designing and managing of water resources systems. This research is carried out to evaluate the ability of Wavelet-ANN and adaptive neuro-fuzzy inference system (ANFIS) techniques for meteorological drought forecasting in southeastern part of East Azerbaijan province, Iran. The Wavelet-ANN and ANFIS models were first trained using the observed data recorded from 1952 to 1992 and then used to predict meteorological drought over the test period extending from 1992 to 2011. The performances of the different models were evaluated by comparing the corresponding values of root mean squared error coefficient of determination (R 2) and Nash–Sutcliffe model efficiency coefficient. In this study, more than 1,000 model structures including artificial neural network (ANN), adaptive neural-fuzzy inference system (ANFIS) and Wavelet-ANN models were tested in order to assess their ability to forecast the meteorological drought for one, two, and three time steps (6 months) ahead. It was demonstrated that wavelet transform can improve meteorological drought modeling. It was also shown that ANFIS models provided more accurate predictions than ANN models. This study confirmed that the optimum number of neurons in the hidden layer could not be always determined using specific formulas; hence, it should be determined using a trial-and-error method. Also, decomposition level in wavelet transform should be delineated according to the periodicity and seasonality of data series. The order of models with regard to their accuracy is as following: Wavelet-ANFIS, Wavelet-ANN, ANFIS, and ANN, respectively. To the best of our knowledge, no research has been published that explores coupling wavelet analysis with ANFIS for meteorological drought and no research has tested the efficiency of these models to forecast the meteorological drought in different time scales as of yet. 相似文献
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