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41.
Steady two-dimensional free convection heat transfer from an isothermal horizontal cylinder located above an adiabatic horizontal surface is studied experimentally and numerically. Experiments are carried out using a Mach–Zehnder interferometer for the ratios of cylinder spacing from the adiabatic surface to its diameter L/D = 0, 0.1, 0.2, 0.3, 0.5, 0.7, and 0.9 and the Rayleigh number range of 500 to 15,000. Also, a specifically developed computer code based on the finite-volume method, the SIMPLE algorithm, and nonorthogonal discretization grid system is used for the solution of the mass-, momentum-, and energy-governing equations for the Rayleigh numbers ranging from 100 to 100,000 and L/D ranging from 0.1 to 1.7. The effects of the Rayleigh number and spacing from the adiabatic surface on both local and average Nusselt numbers around the cylinder are investigated. A correlation based on the numerical data for the average Nusselt number of the cylinder as a function of Rayleigh number and L/D is presented in the aforementioned ranges. 相似文献
42.
43.
Muhammad Masood Ahmad Abdul Razzaq Ghumman Sajjad Ahmad Hashim Nisar Hashmi 《Water Resources Management》2010,24(12):2971-2989
Water resources planning and management requires hydrologic models to estimate runoff from a catchment. For catchments with
limited data, the choice of model and identification of its parameters is very important for development of a direct runoff
hydrograph. A method is presented to determine a unique pair of hydrologic parameters of the Nash Model, number of linear
cascade (n) and storage coefficient (k), using optimization based on Downhill Simplex technique. In this study physical parameters
of the catchment are derived from (SPOT) satellite imageries of the basin using ERDAS software. Four different objective functions
of varying complexity are tested to find the best solution. Weighted root mean square error (RMSE) and Model Efficiency (Nash-Sutcliffe
coefficient) are used to evaluate the model performance. Using the NASH model, a direct surface runoff hydrograph (DSRH) is
developed. Kaha catchment is part of Indus river system and is located in the semi-arid region of Pakistan. This catchment
is dominated by hill torrent flows and is used in this work to demonstrate the applicability of the proposed method. Ten randomly
selected rainfall-runoff events are used for calibration and five events are used for validation. Model results during validation
are very promising with model efficiency exceeding 93% and error in peak discharge under 8%. The sensitivity of the Nash model
output in response to variation in hydrologic parameters n and k is also investigated. When evaluating the hydrologic response
of large catchments, model output is more sensitive to n as compared to k indicating that the runoff diffusion phenomenon
is dominant compared to translation flow effects. 相似文献
44.
A 10-cell Mk 9 stack was characterized using current/voltage mapping during automotive drive cycle testing. A minimally invasive current mapping technique was used to determine localized polarization curves which together with open circuit voltage (OCV) profile measurements provide useful information about crossover leak formation and location. Through a systematic variation of reactant gas pressures it is further possible to distinguish between electrical shorts, diffusive and convective leaks. 相似文献
45.
Fatemeh Ahmadi Zeidabadi Sajjad Amiri Doumari Mohammad Dehghani Zeinab Montazeri Pavel Trojovský Gaurav Dhiman 《计算机、材料和连续体(英文)》2022,70(2):2905-2921
There are many optimization problems in different branches of science that should be solved using an appropriate methodology. Population-based optimization algorithms are one of the most efficient approaches to solve this type of problems. In this paper, a new optimization algorithm called All Members-Based Optimizer (AMBO) is introduced to solve various optimization problems. The main idea in designing the proposed AMBO algorithm is to use more information from the population members of the algorithm instead of just a few specific members (such as best member and worst member) to update the population matrix. Therefore, in AMBO, any member of the population can play a role in updating the population matrix. The theory of AMBO is described and then mathematically modeled for implementation on optimization problems. The performance of the proposed algorithm is evaluated on a set of twenty-three standard objective functions, which belong to three different categories: unimodal, high-dimensional multimodal, and fixed-dimensional multimodal functions. In order to analyze and compare the optimization results for the mentioned objective functions obtained by AMBO, eight other well-known algorithms have been also implemented. The optimization results demonstrate the ability of AMBO to solve various optimization problems. Also, comparison and analysis of the results show that AMBO is superior and more competitive than the other mentioned algorithms in providing suitable solution. 相似文献
46.
Li Xiang Jiang Qing-Zheng Rehman Sajjad Ur Huang Qing-Fang Chen You-Wei Zhao Chuan-Jia Zhong Zhen-Chen 《Journal of Superconductivity and Novel Magnetism》2022,35(1):251-259
Journal of Superconductivity and Novel Magnetism - NdFeB hot-pressed and hot-deformed magnets were prepared by hot-pressed (HP) sintering and spark plasma sintering (SPS). The effects of sintering... 相似文献
47.
Zhong Minglong Xie Weicheng Rehman Sajjad Ur 《Journal of Superconductivity and Novel Magnetism》2022,35(5):1329-1335
Journal of Superconductivity and Novel Magnetism - Microstructure optimization is highly desirable for improving the magnetic properties of permanent magnetic materials. To optimize the... 相似文献
48.
Goudarzi Parisa Rahmani Amir Masoud Mosleh Mohammad 《The Journal of supercomputing》2022,78(15):17202-17230
The Journal of Supercomputing - The cloud of things (CloudIoT) represents a general system of supporting infrastructure for storing and processing information gathered from smart objects and their... 相似文献
49.
Khan Lal Said Khan Majid Jamal Sajjad Shaukat Amin Muhammad 《Multimedia Tools and Applications》2022,81(23):33591-33611
Multimedia Tools and Applications - One of the most critical aspects of this technologically progressive era is the propagation of information through an unsecured communication channel. The... 相似文献
50.