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41.
Empirical evaluation of river basin sustainability affected by inter‐basin water transfer using composite indicators 下载免费PDF全文
Maryam Kefayati Bahram Saghafian Azadeh Ahmadi Hossein Babazadeh 《Water and Environment Journal》2018,32(1):104-111
In this study, a practical approach to evaluate the sustainability of river basins subjected to an inter‐basin water transfer project is developed. Selection of appropriate evaluation indicators is pivotal to such approach. To make use of huge amount of data, composite indicators of sustainability (CIS) should be utilised. The proposed approach relies on 15 sustainability indicators (SI) that cover three major criteria namely (economic, social and environmental), and aggregates them into eight different types of sustainability indices for a more robust outcome. Two scenarios were considered within the source and recipient basins. Furthermore, multivariate principal component analysis (PCA) was applied to determine principal and non‐principal indicators for the two river basins. The ability of CIS and PCA methods were verified via correlation and simple regression methods respectively. The results demonstrated that inter‐basin water transfer may improve sustainability, provided that a proper water resource management is enforced. 相似文献
42.
Ezzatallah Baloui Jamkhaneh Bahram Sadeghpour-Gildeh Gholamhossein Yari 《Structural and Multidisciplinary Optimization》2011,43(4):555-560
In this paper we have designed an acceptance single sampling plan with inspection errors when the fraction of defective items
is a fuzzy number. We have shown that the operating characteristics curve of this plan is like a band having high and low
bounds, its width depends on the ambiguity of proportion parameter in the lot when the samples size and acceptance numbers
are fixed. A comparison of the single sampling plans with and without inspection errors was done to study the effects upon
the characteristics. The results of this comparison show that in the sampling plan with inspection errors, there is a lower
operating characteristics band in comparison to a sampling plan without inspection errors for good processing quality. We
have also shown that the incorrect classification of a good item reduces the fuzzy probability of acceptance and incorrect
classification of a defective item results in a higher fuzzy probability of acceptance. 相似文献
43.
This paper presents a high throughput digital design of the 128-bit Advanced Encryption Standard (AES) algorithm based on the 2-slow retiming technique on FPGA. The C-slow retiming is a well-known optimization and high performance technique. It can enhance designs with feedback loops and automatically rebalances the registers in the design. The C-slow retiming can break the critical path of the design into finer pieces to improve the throughput of the design. The complexity of the C-slow retiming on FPGA is to find the best register allocation in the data path of the design so that by increasing the number of registers, relocation of the registers to balance the AES architecture be in the best mode, and the critical path be optimally pipelined and improved. In this paper, architecture of the AES algorithm is implemented in the gate level by high-speed and breakable structures that are desirable for the 2-slow retiming. The Mix-columns transformation is implemented based on multiplication by constants 2 and 3 modules with combinational logic circuits. This work has been successfully verified and synthesized using Xilinx ISE 11 byVirtex-5, XC5VLX85 FPGA. The proposed implementation achieves a high throughput of 86 Gb/s and high maximum operation frequency of 671.524 MHz whereas the highest throughput and the highest operation frequency reported in the literature are 73.737 Gb/s and 576.07 MHz, respectively. 相似文献
44.
Mohammad Divandari Mehdi Hashemi-Tilehnoee Bahram Asgari-Ziarati Mohammadreza Hosseinkhah Khashayar Sabagh 《核技术(英文版)》2015,(1):53-59
A permanent magnet BLDC(brushless direct current) motor is used to move the control rod of a miniature neutron source reactor(MNSR). The BLDC motor drive is modeled using MATLAB/SIMULINK. Two main parts of the modeling are the inverter switching and the current control. Current control with chopping used to minimize the torque ripple of the MNSR control rod drive. Fuzzy logic current control together with soft chopping control shows the best response of all the three strategies. The prototype drive mechanism has an ATmega32 controller and power MOSFET switches. The simulation results are compared with experimental drive mechanism. 相似文献
45.
Bahram GhaemiGaoling Zhao Guangtao JieHaidong Xi Xiuming LiJianxun Wang Gaorong Han 《Optical Materials》2011,33(6):827-830
Transparent Al2O3-SiO2-ZnO-R2O glass ceramics were fabricated by melting method. The effects of the different kind of alkali ions on the formation of the transparent glass ceramic were studied. X-ray diffraction and high resolution transmission electron microscope were measured to study the microstructure of the samples. The results showed that, transparent glass ceramic including ZnO quantum dots was obtained after heat treatment from 700 °C to 800 °C for the sample containing K2O. While glasses containing Li2O and Na2O were opal after heat treatment. Photoluminescence properties of the K2O contained samples were studied. It was found that the photoluminescence peak shifted to longer wavelength when the heat treatment temperature and time increased, which can be ascribed to the increasing of ZnO quantum dots size. 相似文献
46.
47.
Asadolah Malekzadeh Amir Heydarinasab Bahram Dabir 《Journal of Mechanical Science and Technology》2011,25(2):333-339
The influence of a magnetic field on the skin friction factor of steady fully-developed laminar flow through a pipe was studied
experimentally. A mathematical model was introduced and a finite difference scheme used to solve the governing equations in
terms of vorticity-stream function. The model predictions agree favourably with experimental results. It is observed that
the pressure drop varies in proportion to the square of the product of the magnetic field and the sine of the magnetic field
angle. Also, the pressure drop is proportional to the flow rate. This situation is similar to what applies in the absence
of a magnetic field. It is found that a transverse magnetic field changes the axial velocity profile from the parabolic to
a relatively flat shape. At first, the radial velocity rises more rapidly and then gradually decreases along the pipe until
falling to zero. A numerical correlation can be written for the considerable distance required for the new axial velocity
profile to establish. Owing to the changes taking place in the axial velocity profile, it exhibits a higher skin friction
factor. The new axial velocity profile asymptotically approaches its limit as the Hartmann number becomes large. 相似文献
48.
This paper presents and discusses issues related to structural identification, calibrated model-based load rating, and sensitivity of rating to the analytical model, along with experimental studies conducted on an existing concrete-deck-on-steel-stringer bridge. The proposed model-updating procedure uses collected dynamic data (mode shapes, modal frequencies, and order of modes) as well as static deformed shape information. Two-dimensional (2D) grid models were developed to successfully simulate the transverse load transfer mechanisms between girders, torsional flexibility, and effects of skewed bridge architecture. The rating results obtained from the 2D-grid models were close to 3D-FEM-based evaluation, while simplified 1D bar models had serious shortcomings. Grouping the parameters of the analytical model at different stages of model calibration enhanced the speed and convergence success of the objective function. Although cross-braces are considered as non-structural members, they have been found to be the most critical members of the selected bridge during rating studies. Failure of cross-braces deemed to alter the load transfer mechanism between girders and possibly resulting in the premature failures of interior girders. 相似文献
49.
Regions with densely concentration of industries and district heating systems (DHS) could be interesting study object from the light of an integrated heat market on local basis. System analysis with a widened system boundary could be used as an approach to evaluate the benefit of an integrated heat supply system. In this study, an energy system model consisting of totally seven different participants is designed and the optimization results of the system analysis are presented. With applied data and assumptions, the study shows that a significant amount of the heat demand within two sub‐systems can be covered by heat supply from the heat market (the entire heat comes from two industries). Shadow prices, which can be used for heat pricing, indicate the advantage of an integrated system. The system cost reduction through integration and the availability of several actors with diverse energy supply system, makes the region under study an interesting area to prove a locally deregulated heat market. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
50.
Michael Ortiz Bahram Nour-Omid Elisa D. Sotelino 《International journal for numerical methods in engineering》1988,26(2):379-391
The accuracy of a new class of concurrent, procedures for transient finite element analysis is examined. A phase error analysis is carried out which shows that wave retardation leading to unacceptable loss of accuracy may occur if a Courant condition based on the dimensions of the subdomains is violated. Numerical tests suggest that this Courant condition is conservative for typical structural applications and may lead to a marked increase in accuracy as the number of subdomains is increased. Theoretical speed-up ratios are derived which suggest that the algorithms under consideration can be expected to exhibit a performance superior to that of globally implicit methods when implemented on parallel machines. 相似文献