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71.
Spatio-temporal variation of transition probability of bursting events over the ripples at the bed of open channel 总被引：2，自引：1，他引：1
Saeed Jafari Mianaei Ali Reza Keshavarzi 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(2):257-264
In this study, the turbulent flow structure over the ripples at the bed of open channel was investigated experimentally. An
analysis of bursting process was used to recognize the susceptible regions for sediment entrainment and deposition over the
ripples. Two artificial ripples were built according to the ripples, formed by nature. Three different configurations of ripples
were used by changing the wavelength. According to analysis of bursting event it was found that at the stoss side of ripples,
quadrants (II) and (IV) were dominant to the quadrants (I) and (III) and at the lee side of the ripple it was vice versa.
Also the transition probabilities of the bursting events were determined. The results showed that stable organizations of
each class of the events had highest transition probabilities whereas cross organizations had lowest transition probabilities.
Additionally, an effort was made to find the average inclination angle of the bursting events in quadrants (II) and (IV).
The results showed that the mean angle of events in quadrants (II) and (IV) increases at the downstream of stoss side to the
crest in each experimental test. Also, at the lee side where the sediment particles were deposited, the inclination angles
had the highest values. 相似文献
72.
Vulnerability evaluation of a coastal aquifer via GALDIT model and comparison with DRASTIC index using quality parameters 总被引：1，自引：1，他引：0
In recent years, environmental assessments of groundwater resources have resulted in the development of models that help identify the vulnerable zones. An aquifer is investigated using both GALDIT and DRASTIC indices. The GALDIT model is developed to determine the vulnerability of coastal aquifers in terms of saltwater intrusion whereas the DRASTIC model is generally applicable to all aquifers. Having compared the results of both the GALDIT and DRASTIC models with quality parameters, the salinity model proved to be more appropriate in identifying the vulnerability of coastal aquifers. The results show a Pearson correlation coefficient between TDS and the GALDIT vulnerability map of 0.58 while the corresponding value for the DRASTIC index is 0.48.
EDITOR D. KoutsoyiannisASSOCIATE EDITOR A. Fiori 相似文献
73.
Ali Mahaqi Moheghy Mohammad Anvar Moheghi Mohammad Mehdi Mehiqi Marzieh Zandvakili Zahra 《Water Resources》2020,47(2):325-335
Water Resources - Water in Central Asia is a precious resource in the semiarid and arid environments in which people live in the region. Understanding the groundwater quality is important as it is... 相似文献
74.
Water Resources - Reconnaissance and conceptualization of the system are the first steps to perform an integrated assessment study and step towards sustainability. This paper focuses on the... 相似文献
75.
Natural Hazards - In this study, Dempster–Shafer theory (DST) is integrated into a geographic information system to model vulnerability of the land surface to earthquake events in... 相似文献
76.
Natural Hazards - The aim of this study is to analyze the synoptic and analyzing the mechanisms of flood occurrence on April 1, 2019, in the western half of Iran. In order to statistically analyze... 相似文献
77.
Hasanzadeh Saray Marzieh Eslamian Seyed Saeid Kl&#;ve Bj&#;rn Gohari Alireza 《Theoretical and Applied Climatology》2020,140(1):115-127
Theoretical and Applied Climatology - This study examined the effect of different attributes on regionalization of potential evapotranspiration (ETp) in Urmia Lake Basin (ULB), Iran, using the... 相似文献
78.
Marzieh Mortezapour Brian Menounos Peter L. Jackson Andre R. Erler Ben M. Pelto 《水文研究》2020,34(25):5085-5103
Glaciers are commonly located in mountainous terrain subject to highly variable meteorological conditions. High resolution meteorological (HRM) data simulated by atmospheric models can complement meteorological station observations in order to assess changes in glacier energy fluxes and mass balance. We examine the performance of two snow models, SnowModel and Alpine3D, forced by different meteorological data for winter mass balance simulations at four glaciers in the Canadian portion of the Columbia Basin. The Weather Research and Forecasting model (WRF) with resolution of 1 km and the North American Land Data Assimilation System with ~12 km resolution, provide HRM data for the two snow models. Evaluation is based on the ability of the snow models to simulate snow depth at both point locations (automated snow weather stations) and over the entire glacier surface (airborne LiDAR [Light Detection and Ranging] surveys) during the 2015/2016 winter accumulation. When forced with HRM data, both models can reproduce snow depth to within ±15% of observed values. Both models underestimate winter mass balance when forced by HRM data. When driven with WRF data, SnowModel underestimates winter mass balance integrated over the glacier area by 1 and 10%, whilst Alpine3D underestimates winter mass balance by 12 and 22% compared with LiDAR and stake measurements, respectively. The overall results show that SnowModel forced by WRF simulated winter mass balance the best. 相似文献
79.
Block detection is one of the important steps in all discontinuous methods of analysis such as discontinuous deformation analysis and discrete element method. It is in fact a pre‐processing step for these methods. This paper describes a new approach to the problem of geometrically defining polyhedral rock blocks created by the intersection of planar discontinuities in a rock mass. An approach is developed based on the concept of using matrices with integer elements that mostly represent vertices, edges, or face numbers and their connections. Using square matrices with integer elements and performing edge/face regularization reduce the size of the matrices because of elimination of unnecessary faces, edges, and vertices; speed and accuracy of block tracing operation will be increased. This algorithm is able to trace and identify all kinds of blocks including convex and concave blocks formed by limited or unlimited fractures. The simplicity of the procedure makes it very attractive. The algorithm was programmed in C#.Net by over 8100 code lines; several examples are presented to show application of the algorithm in different situations. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
80.
P. Nassiri Ph.D. M. Azkhosh Ph.D. A. Mahmoodi MSc. I. Alimohammadi Ph.D. H. Zeraati Ph.D. P. Jafari Shalkouhi M.Sc. P. Bahrami B.Sc. 《International Journal of Environmental Science and Technology》2011,8(1):169-176
The purpose of this study was to assess the relationship between psychological stresses and noise stresses on printery workers in Tehran, Iran. Hence, 267 workers were randomly selected. The Leq and Lmaxwere measured and the psychological stresses such as depression, anxiety, aggression and job satisfaction were also studied by the relevant questionnaires. The data were statistically analyzed by Pearson correlation test. The results demonstrated that there was no significant statistical relationship between noise and psychological stresses. In addition, by using Spearman regression method, the influence of variables such as age, gender and job history on psychological stresses caused by Leq and Lmax was studied and the results only revealed that the aggression caused by Leq increased in young personnel (P=0.02) as well as, anxiety caused by L increased accompanied by increasing the job history and age of the workers (P=0.002 and P=0.007). Therefore, more variables must be taken into consideration to judge about noise induced psychological stresses in workplaces. 相似文献