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451.
Naslim N. C. S. Jeffery A. Ahmad N. Behara T. Şahìn 《Astrophysics and Space Science》2010,328(1-2):119-122
We present some preliminary results based on the CoRoT observations of the young distant cluster Dolidze 25. The light curve for the 28 stars observed by the satellite have been analyzed and the relevant periodogram presented. As a result we have found two binary, three Pulsating Be, three SPB, two Spotted and one ellipsoidal variables. Noteworthy, we have also identified one PMS δ Scuti candidate. 相似文献
452.
The hydraulic fracturing technique has been widely applied in many fields, such as the enhanced geothermal systems (EGS), the improvement of injection rates for geologic sequestration of CO2, and for the stimulations of oil and gas reservoirs. The key points for the success of hydraulic fracturing operations in unconventional resources are to accurately estimate the redistribution of pore pressure and stresses around the induced fracture and predict the reactivations of preexisting natural fractures. The pore pressure and stress regime around hydraulic fracture are affected by poroelastic and thermoelastic phenomena as well as by fracture opening compression. In this work, a comprehensive semi-analytical model is used to estimate the stress and pore pressure distribution around an injection-induced fracture from a single well in an infinite reservoir. The model allows the leak-off distribution in the formation to be three-dimensional with the pressure transient moving ellipsoidically outward into the reservoir from the fracture surface. The pore pressure and the stress changes in three dimensions at any point around the fracture caused by poroelasticity, thermoelasticity, and fracture compression are investigated. With Mohr-Coulomb failure criterion, we calculate the natural fracture reactivations in the reservoir. Then, two case studies of constant water injection into a hydraulic fracture are presented. This work is of interest in the interpretation of microseismicity in hydraulic fracturing and in the estimation of the fracture spacing for hydraulic fracturing operations. In addition, the results from this study can be very helpful for the selection of stimulated wells and further design of the refracturing operations. 相似文献
453.
Ahmad ShakibaeiniaYee-Chung Jin 《Advances in water resources》2011,34(6):794-807
Mesh-free particle (Lagrangian) methods such as Moving Particle Semi-Implicit (MPS) and Smoothed Particle Hydrodynamics (SPH) are the latest generation of methods in the field of computational fluid dynamics that attracts lots of attention in modeling applications where large interfacial deformations and fragmentations exist. Due to their mesh-free nature, these methods are capable of simulating any kind of boundary/interface deformation and fragmentations. This study aims to develop a new mesh-free particle model based on the weakly compressible MPS (WC-MPS) formulation for modeling of a dam break over a mobile bed, which is a highly erosive and transient flow problem. A multiphase model, capable of handling the density and viscosity discontinuity and in which the solid (sediment) phase is treated as a non-Newtonian fluid, is introduced. The resulting model is first validated using a two-phase dam break problem and is then applied to the mobile-bed dam break problem with different conditions, comparing the results to those obtained from some experimental works. 相似文献
454.
455.
The Bayana Basin forms the eastern most limit of north Delhi fold belt covering parts of northeastern Rajasthan. The deposition
of sediments took place during middle Proterozoic in fluvial and shallow marine environments. The rocks are mainly clastics
and include conglomerate, sandstone and shale. During mechanical compaction rearrangement of grains took place and point and
long contacts were formed. The sandstones are cemented by iron oxide, silica, carbonate and barite. The porosity has developed
due to dissolution of iron, carbonate cement and feldspar grains. Dissolution of quartz along grain boundaries and silica
rich compaction pore water seems to be the main source of silica. These observations suggest progressive compaction which
initiated at the sediment water interface and continued till deep burial diagenesis in a rapidly subsiding basin. 相似文献
456.
In this research, the efficiency of electrocoagulation treatment process using aluminum electrodes to treat synthetic wastewater containing Reactive Red198 (RR198) was studied. The effects of parameters such as voltage, time of reaction, electrode connection mode, initial dye concentration, electrolyte concentration, and inter electrode distance on dye removal efficiency were investigated. In addition, electrical energy consumption, electrode consumption, and operating cost at optimum condition have been investigated. The results showed that dye and chemical oxygen demand removals were 98.6 and 84%, respectively. Electrode consumption, energy consumption and operating cost were 0.052 kg/m3, 1.303 kWh/m3 and 0.256 US$/m3, respectively. Dye removal kinetic followed first order kinetics. It can be concluded that electrocoagulation process by aluminum electrode is very efficient and clean process for reactive dye removal from colored wastewater. 相似文献
457.
Ummi Nadiah Ahmad Ani Shabri Zahrahtul Amani Zakaria 《Theoretical and Applied Climatology》2013,111(3-4):649-663
TL-moments approach has been used in an analysis to determine the best-fitting distributions to represent the annual series of maximum streamflow data over 12 stations in Terengganu, Malaysia. The TL-moments with different trimming values are used to estimate the parameter of the selected distributions namely: generalized pareto (GPA), generalized logistic, and generalized extreme value distribution. The influence of TL-moments on estimated probability distribution functions are examined by evaluating the relative root mean square error and relative bias of quantile estimates through Monte Carlo simulations. The boxplot is used to show the location of the median and the dispersion of the data, which helps in reaching the decisive conclusions. For most of the cases, the results show that TL-moments with one smallest value was trimmed from the conceptual sample (TL-moments (1,0)), of GPA distribution was the most appropriate in majority of the stations for describing the annual maximum streamflow series in Terengganu, Malaysia. 相似文献
458.
Ali Zulfiqar Hussain Ijaz Faisal Muhammad Grzegorczyk Marco Andreas Almanjahie Ibrahim M. Nazeer Amna Ahmad Ishfaq 《Theoretical and Applied Climatology》2020,140(1):25-36
Theoretical and Applied Climatology - Drought is a complex natural hazard that has been recurrently occurred in many regions across the globe. Therefore, precise drought characterization and its... 相似文献
459.
Immobilization of heavy metals in a contaminated soil in Iran using di-ammonium phosphate,vermicompost and zeolite 总被引:2,自引:0,他引:2
Fractionation of heavy metals (HMs) in amended soils is needed to predict elemental mobility in soil and phytoavailability
to plants. A study was conducted to determine the effects of different amendments on HMs availability and their redistribution
among soil fractions. A contaminated soil was selected from around a Zn mine and amended with 0, 2, 4, and 6 g kg−1 of vermicompost (VC), zeolite (ZE), and di-ammonium phosphate (DP) and incubated at field moisture. The amounts of Cd, Pb,
Zn, and Cu were determined from the soil after 6 months of incubation time using DTPA and sequential extraction procedures.
The total concentrations of Cd, Pb, Zn, and Cu were 41, 3,099, 1,997, and 83 mg kg−1 of soil, respectively. All amendments decreased significantly [probability (p) ≤ 0.05] DTPA-extractable Cd, Pb, and Cu, but not Zn, in the soil. For instance, DTPA-extractable Cd, Pb, and Cu decreased
by 40, 290, and 20%, respectively, and that of Zn increased by 18% with DP1 (2 g kg−1 of di-ammonium phosphate) application. The concentrations of Pb and Cd decreased mainly in the specifically sorbed (SS) but
increased in the amorphous Fe oxide (AFeO) fraction with DP application, indicating redistribution of Pb and Cd in the fractions
with less mobility. Lead immobilization by DP was mainly attributed to the P-induced formation of chloropyromorphite, which
was identified in the DP treatment using X-ray diffraction technique. It was concluded that DP was the most effective amendment
in immobilizing Pb and Cd, though it increased Zn mobility. 相似文献
460.
In Pakistan,the solar analogue has been addressed but its surface geographical parameterization has given least attention.Inappropriate density of stations and their spatial coverage particularly in difficult peripheral national territories,little or no solar radiation data,non-satisfactory sunshine hours data,and low quality of ground observed cloud cover data create a situation in which the spatial modeling of Extraterrestrial Solar Radiation(ESR) and its ground parameterization got sufficient scope.The D... 相似文献