Impact of downstream lakes on dam break wave attenuation     

Fan  Jihui  Motamedi  Artemis  Galoie  Majid 《Natural Hazards》2021,106(1):595-612

In this study, the effect of downstream lakes or ponds on dam break flow was investigated. To do this, a robust finite volume method with Harten-Lax-van Leer contact surface Riemann’s solver technique for flux evaluation has been used. For space discretization, a triangular mesh grid was used and a complete software with mesh generator was developed. A reservoir with a long downstream channel was assumed, and many scenarios such as a single lake with various lengths, widths and positions along the channel and multiple consecutive lakes as symmetric and non-symmetric with respect to the channel centerline were considered. The numerical modeling of dam break flow along the channel showed that the downstream lake can decrease the speed and depth of the dam break wave front and the amount of this wave attenuation was very dependent on the storage volume of the lake and vortexes which were established in the lake.

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Application of soft-computing techniques in forecasting sediment load and concentration     

Sina Ghanbarynamin  Majid Zaremehrjardy 《水文科学杂志》2020,65(13):2309-2321

ABSTRACT

This paper investigates conventional and soft-computing methods for the estimation of suspended sediment concentration (SSC) and load (SSL) in rivers. Frequently used methods of sediment rate curve (SRC) and multi-nonlinear regression, and soft-computing methods of multi-layer perceptron, multi-linear regression and adaptive neuro-fuzzy inference system are implemented using various hydrological and hydraulic parameters for the Little Kickapoo Creek Watershed, Illinois, USA. All methods performed equally well in the estimation of SSL, without any noticeable outperformance from any from the methods. However, the application of soft-computing methods decreased SSC estimation errors considerably as compared to the results of SRC. The results are significant in the way they reconcile traditionally used hydrological parameters into the soft-computing methods. Overall, soft-computing methods are recommended for the estimation of SSC in rivers because of their reasonably better performance and ease of implementation.  相似文献   

Ground Water Remediation Using an Extraction, Treatment, and Recharge System     

Kurt O. Thomsen  Majid A. Chaudhry  Kostas Dovantzis  Ronald R. Riesing 《Ground Water Monitoring & Remediation》1989,9(1):92-99

Ground water remediation of volatile organic compound (VOC) contamination at a site in Michigan was initiated as a result of a consent agreement between the Michigan Department of Natural Resources (MDNR) and the responsible party. Under the direction of the MDNR, the responsible party conducted a remedial investigation/feasibility study using federal guidelines to define the extent of contamination at the site and to select a response action for site remediation. The selected alternative included a combination of ground water extraction, treatment, and recharge, and soil flushing. The extraction system withdraws ground water from various depths in heavily contaminated areas. The ground water is treated using an air stripper. A spray distribution system spreads effluent from the stripper over a recharge basin constructed over the most contaminated areas. Additional contaminant removal is achieved by volatilization from the spray and percolation through the gravel bed. Recharge water moves downward through the contaminated soils, thus flushing residual soil contaminants. The initial operating data demonstrated that the system can effectively remove trichloroethylene (TCE) from ground water (approximately 95 percent overall removal efficiency). The annualized capital and operation and maintenance (O & M) costs of the remedial action were estimated for several operating periods (15, 20, and 30 years).  相似文献   

An investigation on Kangan gas refinery wastewater     

S. M. T. Sadatipour  L. Mirzaie  A. A. Rezaei 《International Journal of Environmental Science and Technology》2004,1(3):205-213

Kangan Gas Refinery is one of the greatest gas refineries in Iran. Environmental affects of this refinery should be assessed because of its high economic importance, as well as its considerable revenue. Since the gas refinery is classified in highly polluted industry, therefore the impact of wastewater the refinery should be determined. This research is carried out on March 2002 at Kangan refinery, which is located in Kangan city, southern part of Iran. The gas refinery wastewater generally includes oil, hydrocarbon materials and chemical additives, which are in the form of emulsion in water. The following parameters, such as oil and grease, PAHs, BOD, TH, turbidity, COD, EC, pH, TSS, SiO₂, PO₄ are determined in wastewater of the refinery in order to determine the amount of pollutants, which are affecting the area where the refinery is located. The oil and grease are analyzed by FTIR and PAHs are determined by UV-Luminance and physico-chemical parameters are determined according to the Standard Methods. The results show that although pollution of the refinery wastewater is within world permissible limits (EPA), but since the area is affected by the wastewater and surrounding area is confined with river basin it could be concluded that pollutants, which are discharged to the echo environment, are not in the permissible limits of the similar Industries.  相似文献   

Evaluation of the Iranian guideline for deismic rehabilitation of existing buildings     

Ali Reza Keyvani Boroujeni Majid Sadeghazar 《地震工程与工程振动(英文版)》2006,5(2):297-307

The Iranian Guideline for Seismic Rehabilitation of Existing Buildings （GSREB）, which is currently used for vulnerability assessment of existing buildings in Iran, is evaluated in this paper. The vulnerability of sample buildings of a variety stories with special steel moment resisting frames, designed according to the Standard No.2800 requirements, is assessed by GSREB. In the vulnerability assessment, different analysis methods were used and the results, in terms of usage ratio, defined as the ratio of the strength/deformation demand to the corresponding capacity, are compared. Numerical results show that some columns of these buildings do not satisfy the life safety performance criteria in the design hazard level. Moreover, the target displacement estimated by the Displacement Coefficient Method （DCM） is larger than the maximum displacement calculated by nonlinear dynamic analysis.  相似文献   

Effect of inertia nonlinearity on dynamic response of an asymmetric building equipped with tuned mass dampers     

Hassan Rezazadeh  Fereidoun Amini  Majid Amin Afshar 《地震工程与工程振动(英文版)》2020,19(2):499-513

This study investigates the effect of nonlinear inertia on the dynamic response of an asymmetric building equipped with Tuned Mass Dampers (TMDs). In the field of structural engineering, many researchers have developed models to study the behavior of nonlinear TMDs, but the effect of nonlinear inertia has not received as much attention for asymmetric buildings. To consider nonlinear inertia, the equations of motion are derived in a local rotary coordinates system. The displacements and rotations of the modeled building and TMDs are defined by five-degree-of-freedom (5-DOFs). The equations of motion are derived by using the Lagrangian method. Also in the proposed nonlinear model, the equations of motion are different from a conventional linear model. In order to compare the response of the proposed nonlinear model and a conventional linear model, numerical examples are presented and the response of the modeled buildings are derived under harmonic and earthquake excitations. It is shown that if the nonlinear inertia is considered, the response of the modeled structures changes and the conventional linear approach cannot adequately model the dynamic behavior of the asymmetric buildings which are equipped with TMDs.  相似文献   

Application of the microtremor measurements to a site effect study          下载免费PDF全文

Sadegh Rezaei  Asskar Janalizadeh Choobbasti 《地震科学（英文版）》2017,30(3):157-164

Earthquake has left much life and property damages. The occurrence of such events necessitates the execution of plans for combating the earthquakes. One of the most important methods for combating earthquakes includes assessing dynamic characteristics of soil and site effect. One of the methods by which one can state dynamic characteristics of the soil of an area is the measurement of microtremors. Microtremors are small-scale vibrations that occur in the ground and have an amplitude range of about0.1–1 microns. Microtremor measurement is fast, applicable, cost-effective. Microtremor measurements were taken at 15 stations in the Babol, north of Iran. Regarding H/V spectral ratio method, peak frequency and amplification factor were calculated for all microtremor stations.According to the analysis, the peak frequency varies from0.67 to 8.10 Hz within the study area. Also, the authors investigated the validity of the results by comparing them with SESAME guidelines and geotechnical conditions of study area. The microtremor analysis results are consistent with SESAME guidelines and geotechnical condition of study area. The results show that the microtremor observations are acceptable methods for assessing dynamic characteristics of soil and site effect in the Babol City.  相似文献   

A fast joint seismic data reconstruction by sparsity‐promoting inversion          下载免费PDF全文

Lanshu Bai  Huiyi Lu  Yike Liu  Majid Khan 《Geophysical Prospecting》2017,65(4):926-940

Seismic field data are often irregularly or coarsely sampled in space due to acquisition limits. However, complete and regular data need to be acquired in most conventional seismic processing and imaging algorithms. We have developed a fast joint curvelet‐domain seismic data reconstruction method by sparsity‐promoting inversion based on compressive sensing. We have made an attempt to seek a sparse representation of incomplete seismic data by curvelet coefficients and solve sparsity‐promoting problems through an iterative thresholding process to reconstruct the missing data. In conventional iterative thresholding algorithms, the updated reconstruction result of each iteration is obtained by adding the gradient to the previous result and thresholding it. The algorithm is stable and accurate but always requires sufficient iterations. The linearised Bregman method can accelerate the convergence by replacing the previous result with that before thresholding, thus promoting the effective coefficients added to the result. The method is faster than conventional one, but it can cause artefacts near the missing traces while reconstructing small‐amplitude coefficients because some coefficients in the unthresholded results wrongly represent the residual of the data. The key process in the joint curvelet‐domain reconstruction method is that we use both the previous results of the conventional method and the linearised Bregman method to stabilise the reconstruction quality and accelerate the recovery for a while. The acceleration rate is controlled through weighting to adjust the contribution of the acceleration term and the stable term. A fierce acceleration could be performed for the recovery of comparatively small gaps, whereas a mild acceleration is more appropriate when the incomplete data has a large gap of high‐amplitude events. Finally, we carry out a fast and stable recovery using the trade‐off algorithm. Synthetic and field data tests verified that the joint curvelet‐domain reconstruction method can effectively and quickly reconstruct seismic data with missing traces.  相似文献   

Composts Containing Natural and Mg‐Modified Zeolite: The Effect on Nitrate Leaching,Drainage Water,and Yield     

Hajar Taheri‐Soudejani  Manouchehr Heidarpour  Mohammad Shayannejad  Hossein Shariatmadari  Hossein Kazemian  Majid Afyuni 《洁净——土壤、空气、水》2019,47(8)

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Evaluation of Ordinary Least Square (OLS) and Geographically Weighted Regression (GWR) for Water Quality Monitoring: A Case Study for the Estimation of Salinity     

Majid Nazeer  Muhammad Bilal 《中国海洋大学学报(英文版)》2018,17(2):305-310

Landsat-5 Thematic Mapper (TM) dataset have been used to estimate salinity in the coastal area of Hong Kong. Four adjacent Landsat TM images were used in this study, which was atmospherically corrected using the Second Simulation of the Satellite Signal in the Solar Spectrum (6S) radiative transfer code. The atmospherically corrected images were further used to develop models for salinity using Ordinary Least Square (OLS) regression and Geographically Weighted Regression (GWR) based on in situ data of October 2009. Results show that the coefficient of determination (R²) of 0.42 between the OLS estimated and in situ measured salinity is much lower than that of the GWR model, which is two times higher (R² = 0.86). It indicates that the GWR model has more ability than the OLS regression model to predict salinity and show its spatial heterogeneity better. It was observed that the salinity was high in Deep Bay (north-western part of Hong Kong) which might be due to the industrial waste disposal, whereas the salinity was estimated to be constant (32 practical salinity units) towards the open sea.  相似文献