Nutrient Recovery from Domestic Effluent using an Indigenous Strain of Scenedesmus sp.          下载免费PDF全文

Radin Maya Saphira Radin Mohamed  Adel Al‐Gheethi  Ramlah Buyong  Nor Haslina Hashim  Hazel Monica Matias‐Peralta  Amir‐Hashim Mohd‐Kassim 《洁净——土壤、空气、水》2018,46(8)

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Enhancing Groundwater Remediation in Air Sparging by Changing the Pulse Duration     

Asaf B. Neriah  Amir Paster 《Ground Water Monitoring & Remediation》2019,39(1):43-53

An important operation parameter in the design of a pulsed air sparging (PAS) system is the pulse duration (PD). To study the effect of the PD on the remediation process, a series of laboratory experiments and numerical simulations were performed. The experimental apparatus was a cylindrical tank, packed with fine sand and partially filled by water contaminated with toluene. Toluene concentrations in water and in effluent air were measured over time during the application of PAS, which was applied with three different PD. Next, the T2VOC model, an extension of the TOUGH2 simulation program, was used to simulate the two-phase flow and transport processes for these cases. The simulation model was calibrated to the experimental results, and then run with a range of PD values. Results showed that there exists an optimal PD which yields the highest remediation efficiency. Next, it was shown that this PD may be obtained by performing a PAS pilot test and measuring the groundwater pressure response in a monitoring well. The characteristic time which describes the exponential decay of the pressure response was shown to provide an adequate estimate for the optimal PD. The estimation improved by taking a number of injection cycles.  相似文献   

Effect of Orientation on the Variability Pattern of Gamma-Ray Sources     

Amir Levinson 《Astrophysics and Space Science》1999,268(4):433-441

Using a toy model, we demonstrate how the variability pattern of a relativistically moving source of radiation that is subject to the action of a transient force, depends on dynamical effects. The model is motivated by a recent analysis of radiative fronts in magnetized, relativistic jets, but is applicable also in other situations. The main effect analyzed in this paper is the strong dependence of the variability pattern on viewing angle, resulting from changes of the beaming cone of emission. In particular, it is shown that(1) the shape of the light curves reflects the time profile of the Doppler factor when viewing the source at large enough angles to its direction of motion, whereas at small viewing angles it is determined by the time evolution of the radiated power density; and(2) the characteristics of correlated emission depend strongly on viewing angle by virtue of either optical depth effects or the difference in beaming patterns of different radiation sources. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

A bridge between dual porosity and multiscale models of heterogeneous deformable porous media     

Mohammad R. Hajiabadi  Amir R. Khoei 《国际地质力学数值与分析法杂志》2019,43(1):212-238

In this paper, a multiscale homogenization approach is developed for fully coupled saturated porous media to represent the idealized sugar cube model, which is generally employed in fractured porous media on the basis of dual porosity models. In this manner, an extended version of the Hill-Mandel theory that incorporates the microdynamic effects into the multiscale analysis is presented, and the concept of the deformable dual porosity model is demonstrated. Numerical simulations are performed employing the multiscale analysis and dual porosity model, and the results are compared with the direct numerical simulation through 2 numerical examples. Finally, a combined multiscale-dual porosity technique is introduced by employing a bridge between these 2 techniques as an alternative approach that reduces the computational cost of numerical simulation in modeling of heterogeneous deformable porous media.  相似文献   

Analysis of 2010-flood causes, nature and magnitude in the Khyber Pakhtunkhwa, Pakistan     

Atta-ur-Rahman  Amir Nawaz Khan 《Natural Hazards》2013,66(2):887-904

This article attempts to analyse the nature, magnitude and causes of 2010 disastrous flood that seriously affected the province of Khyber Pakhtunkhwa (KPK), Pakistan. Pakistan is famous for its summer floods, but the flood of 2010 is considered to be the century’s worst. It has broken all the previous records in terms of discharge, damages and amount of rainfall occurred. Most of the meteorological stations have received rainfall above normal. Data for this study were collected both from primary and secondary sources. A total 150 questionnaires were filled in from the flood victims. However, secondary data were obtained from the Pakistan Meteorology Department, Flood Forecasting and Warning Centre, Federal Flood Commission, Provincial Disaster Management Authority, National Disaster Management Authority, Surface Water Hydrology Department and Provincial Irrigation and Drainage Authority. The analysis reveals that heavy and prolonged rainfall for four consecutive days (27–30 July) was the major cause of 2010-flood. In addition to this, the development of unusual low pressure zone over the northern Pakistan, aggradations of river bed, rapid deforestation, ponding back of river by motorway, blocking of bridges by tree trunks and subsequent bursting of temporary dams have played their role in causing the disastrous flood in almost all the rivers of KPK. This has inflicted terrible damages to human lives, standing crops, housing, infrastructure and other properties.  相似文献   

Self-organizing maps for multi-scale morphometric feature identification using shuttle radar topography mission data     

Amir Houshang Ehsani  Friedrich Quiel 《国际地球制图》2013,28(5):335-355

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Total load transport in gravel bed and sand bed rivers case study:Chelichay watershed     

Arman HADDADCHI  Mohammad H.OMID  Amir A.SDEHGHANI 《国际泥沙研究》2013,28(1):46-57

Field experiments were conducted on total load transport in the Chelichay River Basin,a mountainous catchment (1,400 km~2) located in north eastern of Iran,to evaluate total load formulas including four gravel bed rivers and a sand bed river(Qaresoo River).Gravel bed rivers in Chelichay River Basin can be grouped into two types;steep slope rivers with high shear values(Chehelchay River and Khormaloo River) and mild slope rivers with low shear values(Narmab River and Soosara River).Two depth integrating suspended load samplers(DH-48 and D-49),and two bed load samplers(Helley-Smith and BLSH) were used to measure total load.The performance is tested of 8 total load transport formulae including 4 macroscopic and 4 microscopic methods.A systematic and thorough analysis of 59 sets of data collected from sand bed river indicate that Yang and Engelund and Hansen reach to the better results, and from four gravel bed rivers confirmed that the methods of Karim and Kennedy and Engelund and Hansen yields the best results for steep slope rivers,and the methods of Einstein and Bijker are ranked highest in gradual slope rivers.  相似文献   

Syn-depositional halokinesis in the Zechstein Supergroup (Lopingian) controls Triassic minibasin genesis and location     

Amir Joffe  Christopher A.-L. Jackson  Leonardo M. Pichel 《Basin Research》2023,35(2):784-801

Salt tectonics is typically caused by the flow of mobile evaporites in response to post-depositional gravity gliding and/or differential loading by overburden sediments. This situation is considerably more complex near the margins of salt basins, where carbonate and clastic rocks may be deposited at the same time as and be interbedded with more mobile, evaporitic strata. In these cases, syn-depositional salt flow may occur due to density differences in the deposited lithologies, although our understanding of this and related processes is relatively poor. We here use 3D seismic reflection and borehole data from the Devil's Hole Horst, West Central Shelf, offshore UK to understand the genesis, geometry, and kinematic evolution of intra-Zechstein Supergroup (Lopingian) minibasins and their effect on post-depositional salt deformation. We show that immobile, pinnacle-to-barrier-like, carbonate build-ups and anhydrite are largely restricted to intra-basin highs, whereas mobile halite, which flowed to form large diapirs, dominates in the deep basin. At the transition between the intra-basin highs and the deep basin, a belt of intra-Zechstein minibasins occurs, forming due to the subsidence of relatively dense anhydrite into underlying halite. Depending on primary halite thickness, these intra-Zechstein minibasins created topographic lows, dictating where Triassic minibasins subsequently nucleated and down-built. Our study refines the original depositional model for the Zechstein Supergroup in the Central North Sea, with the results also helping us better understand the style and distribution of syn-depositional salt flow within other layered evaporitic sequences and the role intra-salt heterogeneity and related deformation may have in the associated petroleum plays.  相似文献   

Slope stability analyzing using recent swarm intelligence techniques          下载免费PDF全文

Amir H. Gandomi  Ali R. Kashani  Mehdi Mousavi  Mehdi Jalalvandi 《国际地质力学数值与分析法杂志》2015,39(3):295-309

Slope stability analysis of soil with a weak layer sandwiched between two strong layers is considered as a complex geotechnical problem. In this problem, the objective function is non‐convex and discontinuous with the presence of multiple strong local minima. Classical optimization techniques fail to converge to a valid solution unless a proper initial trial is adopted. Even though many new optimization algorithms have emerged, they have not been applied to geotechnical problems yet. In the present study, some recent swarm intelligence algorithms are adopted for some complicated example of slope stability problems and benchmarked with the traditional particle swarm optimization algorithm. From the results, it seems the levy flight krill herd algorithm is the most efficient method over proposed algorithms for this kind of problem. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Real-time mapping of earthquake-induced landslides     

Amir M. Kaynia  Elin Skurtveit  Gokhan Saygili 《Bulletin of Earthquake Engineering》2011,9(4):955-973

Rigid sliding block analysis is a common analytical procedure used to predict the potential for earthquake-induced landslides for natural slopes. Currently, predictive models provide the expected level of displacement as a function of the characteristics of the slope (e.g., geometry, strength, yield acceleration) and the characteristics of earthquake shaking (e.g., peak ground acceleration, peak ground velocity). These predictive models are used for developing seismic landslide hazard maps which identify zones with risk of earthquake-induced landslides. Alternatively, these models can be combined with Shakemaps to generate “near-real-time” Slidemaps which could be used, among others, as a tool in disaster management. Shakemaps (a publicly available free service of the United States Geological Survey, USGS) provide near-real-time ground motion conditions during the time of an earthquake event. The ground motion parameters provided by a Shakemap are very useful for the development of Slidemaps. By providing ground motion parameters from an actual earthquake event, Shakemaps also serve as a tool to decouple the uncertainty of the ground motion in sliding displacements prediction. Campania region in Italy is studied for assessing the applicability of using Shakemaps for regional landslide-risk assessment. This region is selected based on the availability of soil shear strength parameters and the proximity to the 1980 Irpina (M _w  = 6.9) Earthquake.  相似文献