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41.
Water Resources - The lack of water resources as a critical substance and the increase of water demands and also the complexity of water resources management issues are made the integrated water... 相似文献
42.
Arman?GanjiEmail author Laxmi?Sushama Diana?Verseghy Richard?Harvey 《Theoretical and Applied Climatology》2017,127(1-2):45-59
Regional and global climate model simulated streamflows for high-latitude regions show systematic biases, particularly in the timing and magnitude of spring peak flows. Though these biases could be related to the snow water equivalent and spring temperature biases in models, a good part of these biases is due to the unaccounted effects of non-uniform infiltration capacity of the frozen ground and other related processes. In this paper, the treatment of frozen water in the Canadian Land Surface Scheme (CLASS), which is used in the Canadian regional and global climate models, is modified to include fractional permeable area, supercooled liquid water and a new formulation for hydraulic conductivity. The impact of these modifications on the regional hydrology, particularly streamflow, is assessed by comparing three simulations performed with the original and two modified versions of CLASS, driven by atmospheric forcing data from the European Centre for Medium-Range Weather Forecast (ECMWF) reanalysis (ERA-Interim) for the 1990–2001 period over a northeast Canadian domain. The two modified versions of CLASS differ in the soil hydraulic conductivity and matric potential formulations, with one version being based on formulations from a previous study and the other one is newly proposed. Results suggest statistically significant decreases in infiltration and therefore soil moisture during the snowmelt season for the simulation with the new hydraulic conductivity and matric potential formulations and fractional permeable area concept compared to the original version of CLASS, which is also reflected in the increased spring surface runoff and streamflows in this simulation with modified CLASS over most of the study domain. The simulated spring peaks and their timing in this simulation are also in better agreement to those observed. This study thus demonstrates the importance of treatment of frozen water for realistic simulation of streamflows. 相似文献
43.
A new remedy is proposed in this study to increase the ductility of cross-braced frames to a level comparable with ductile moment frames. The suggested system consists of one or two concentric steel rings installed in the cross-braced bay vertically. The steel rings are designed such that they fail in bending sooner than failure of the braces in compression. Then the rings act as seismic fuses with multiple bending plastic hinges. Using nonlinear static analysis, it is shown that the proposed system can be designed to behave like cross-braced frames with regard to stiffness and strength, and like special moment frames with regard to ductility. Seismic design factors for the proposed system are recommended based on nonlinear pushover and cyclic analysis studies.
相似文献44.
This study investigates the effects of underground obstacles on a Rayleigh Wave dispersion curve obtained by spectral analysis of surface waves (SASW) testing. The SASW test is simulated by a transient response analysis of an axisymmetric finite element method. Both rigid obstacles and cavities with a variety of shapes and embedment depths are considered. Results show strong fluctuations in the dispersion curve obtained from the signals recorded by receivers in the vicinity of an obstacle. The fluctuations are primarily a result of wave reflections from the near and far faces of an obstacle. Results obtained from a finite element model are explained through a comparison with a simple theoretical model and experimental results are published. Fluctuations shown in the dispersion curve can result in misinterpretation of the shear wave velocity profile. Wherever obstacles are known to exist, an SASW test should be performed in a way that minimizes these effects. The parameters that will reduce or aggravate these effects were studied and are discussed. 相似文献
45.
A. I. Okay M. B. Arman M. C. Göncüoglu 《Contributions to Mineralogy and Petrology》1985,91(2):196-204
Eclogites are found as lenses or layers in the Precambrian gneiss terrain of the Bitlis Massif in eastern Turkey. Kyanite-eclogites from the region of Gablor Hill in the Bitlis Massif exhibit relatively minor alteration, and consist of garnet, omphacite, kyanite, zoisite, calcic amphibole, phengite, rutile and quartz. In terms of geological setting and mineral compositions, Gablor eclogites are very similar to eclogites from high-grade gneiss terrains. Metamorphic conditions during the eclogite crystallisation are determined as 625±35° C and 16±3 kbars. The coexistence of white mixa, omphacite and kyanite constrains
between 0.4 and 1. Primary calcic amphiboles from the Gablor eclogites exhibit conflicting textures, indicating stable coexistence with, as well as growth from omphacite and garnet. This is explained by a buffering reaction between amphibole, garnet, omphacite, zoisite and kyanite during the eclogite crystallisation, whereby
is controlled and buffered by the mineral assemblage. 相似文献
46.
Nefize Shaban Alp Caner Ahmet Yakut Aysegul Askan Ali Karimzadeh Naghshineh Arman Domanic Gizem Can 《地震工程与结构动力学》2015,44(6):889-905
Presence of vehicles on a bridge has been observed many times during past earthquakes. Although in practice, the engineers may or may not include the live load contribution to seismic weight in design, current bridge design codes do not specify a certain guideline. A very limited research has been conducted to address this issue from design point of view. The focus of this research is to experimentally assess the effect of a vehicle on the seismic response of a bridge through a large‐scale model. In this scope, a 12‐meter long bridge, having a one lane deck with concrete slab on steel girders, has been shaken under five different ground motions obtained from recent earthquakes that occurred in Turkey, in its transverse direction, both with and without a vehicle on top of the deck. The measured results have indicated that top slab transverse acceleration and bearing displacements can reduce up to 18.7% in presence of a vehicle during seismic tests, which is an indication of reduction in substructure forces. The main reason for the reduction in seismic response of the bridge in the presence of live load can be ascribed to the increase in damping of the system due to mass damper‐like action induced by the vehicle. This beneficial effect cannot be observed in vertical seismic response. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
47.
Advance first order second moment (AFOSM) method for single reservoir operation reliability analysis: a case study 总被引：1，自引：1，他引：0
A. Ganji L. Jowkarshorijeh 《Stochastic Environmental Research and Risk Assessment (SERRA)》2012,26(1):33-42
Reservoir system reliability is the ability of reservoir to perform its required functions under stated conditions for a specified
period of time. In classical method of reservoir system reliability analysis, the operation policy is used in a simple simulation
model, considering the historical/synthetic inflow series and a number of physical bounds on a reservoir system. This type
of reliability analysis assumes a reservoir system as fully failed or functioning, called binary state assumption. A number
of researchers from various research backgrounds have shown that the binary state assumption in the traditional reliability
theory is not extensively acceptable. Our approach to tackle the present problem space is to implement the algorithm of advance
first order second moment (AFOSM) method. In this new method, the inflow and reservoir storage are considered as uncertain
variables. The mean, variance and covariance of uncertain variables are determined using moment values of reservoir state
variables. For this purpose, a stochastic optimization model developed based on the constraint state formulation is applied.
The proposed model of reliability analysis is used to a real case study in Iran. As a result, monthly probabilities of water
allocation were computed from AFOSM method, and the outputs were compared with those from Monte Carlo method. The comparison
shows that the outputs from AFOSM method are similar to those from the Monte Carlo method. In term of practical use of this
study, the proposed method is appropriate to determine the monthly probability of failure in water allocation without the
aid of simulation. 相似文献
48.
This paper describes analytical and numerical methods to analyze the steady state periodic response of an oscillator with
symmetric elastic and inertia nonlinearity. A new implementation of the homotopy perturbation method (HPM) and an ancient
Chinese method called the max-min approach are presented to obtain an approximate solution. The major concern is to assess
the accuracy of these approximate methods in predicting the system response within a certain range of system parameters by
examining their ability to establish an actual (numerical) solution. Therefore, the analytical results are compared with the
numerical results to illustrate the effectiveness and convenience of the proposed methods. 相似文献
49.
M. Khosravi M. Taghi Ganji R. Rakhshaee 《International Journal of Environmental Science and Technology》2005,2(1):35-40
The limitation of plant growth in the polluted mediums can be used as a factor to determine of plant tolerance and the toxic effect of these mediums. In this work, the effect of Pb2+, Cd2+, Ni2+and Znsu2+ (individually) on Azolla filiculoides growth in the aqueous solution and using this method to water post treatment were studied. During 15 days the biomass the fresh Azolla with initial mass of 20 g was grown on the nutrient solution containing these metal ions, each in a concentration 4 mg/l. The presence of these ions, caused about 25%, 42%, 31% and 17% inhibition of biomass growth, respectively, in comparison to Azolla control weight which had not heavy metals. The water salinity of 1, 2 and 4 g. NaCl/l decreased the removal of these heavy metals about 4–7%, 20–24% and 40–55%, respectively. The addition of total dissolved solids (TDS) from 50 to 300 ppm. (as CaCO3) into the samples of containing heavy metals increased Azolla growth, but decreased the control Azolla growth. 相似文献
50.
Calvin W. Rose Jon M. Olley Arman Haddadchi Andrew P. Brooks Joe McMahon 《地球表面变化过程与地形》2018,43(3):735-742
The jet erosion test (JET) is a widely applied method for deriving the erodibility of cohesive soils and sediments. There are suggestions in the literature that further examination of the method widely used to interpret the results of these erosion tests is warranted. This paper presents an alternative approach for such interpretation based on the principle of energy conservation. This new approach recognizes that evaluation of erodibility using the jet tester should involve the mass of soil eroded, so determination of this eroded mass (or else scour volume and bulk density) is required. The theory partitions jet kinetic energy flux into that involved in eroding soil, the remainder being dissipated in a variety of mechanisms. The energy required to erode soil is defined as the product of the eroded mass and a resistance parameter which is the energy required to entrain unit mass of soil, denoted J (in J/kg), whose magnitude is sought. An effective component rate of jet energy consumption is defined which depends on depth of scour penetration by the jet, but not on soil type, or the uniformity of the soil type being investigated. Application of the theory depends on experimentally determining the spatial form of jet energy consumption displayed in erosion of a uniform body of soil, an approach of general application. The theory then allows determination of the soil resistance parameter J as a function of depth of scour penetration into any soil profile, thus evaluating such profile variation in erodibility as may exist. This parameter J has been used with the same meaning in soil and gully erosion studies for the last 25 years. Application of this approach will appear in a companion publication as part 2. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献