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Assessment and prioritization of soil erosion triggering factors using analytical hierarchy process and Taguchi method

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International Journal of Sediment Research 2023年第3期38卷 396-404页

作者： Mehdi Hayatzadeh vahid Moosavi Ramyar Aliramaee Department of Nature Engineering Faculty of Agriculture and Natural Resources Ardakan University Department of Watershed Management Engineering Faculty of Natural Resources and Marine Sciences Tarbiat Modares University Khamsan Representative and Paired Watershed

The main aims of this study are assessing some factors which affect the soil erosion process and evaluating the results of an analytical hierarchy process(AHP) method using the Taguchi method. Firstly, the weights for those factors and levels affecting soil erosion were determined by the AHP method. The determination of weights was based on the opinions of academic researchers, experts, middle managers,and members of the Soil and Water Research Centers in Iran. Secondly, an L32 Taguchi orthogonal array was selected based on the number of factors and levels for the current problem. Accordingly, 32 rainfall events were simulated and sediment yield amounts were measured. Analyzing the results of the Taguchi method, the weights of factors and levels were determined. The results showed that the weights obtained from the AHP method were not in accordance with the results of field measurements and the Taguchi analysis. The AHP method indicated that the main factors have the following order of importance: geological formation, rainfall intensity, silt content of soil as an indicator for the soil texture,vegetation cover, slope steepness, and slope aspect in the study area. However, the Taguchi method found the following order for the main factors: rainfall intensity, geological formation, silt content of soil as an indicator for the soil texture, slope steepness, vegetation cover, and slope aspect. As the Taguchi method works based on the quantitative measurements, the Taguchi results are more reliable rather than subjective methods such as AHP. It was also concluded that the AHP method should be used cautiously in assessing natural phenomena. Therefore, in the cases that in situ measurements are possible, it is better to use quantitative mathematical and statistical methods than to rely to qualitative knowledge based approaches.

关键词： Soil erosion Taguchi method Analytical hierarchy process (AHP) method Optimization

Forty-year investigation of wave power in energetic region of Persian Gulf in Iranian territorial waters by using short-term and new long-term stability assessment parameters

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Acta Oceanologica Sinica 2023年第10期42卷 75-83页

作者： Fouad Salimi Cyrus Ershadi vahid Chegini Department of Civil Engineering University of HormozganBandar Abbas *** P.OBOX:3995Iran Department of Coastal Engineering Islamic Azad University(Central Tehran Branch)Tehran ***Iran

The wave power in high potential area of the northern Persian Gulf(near to Iranian coastal areas)is assessed by taking into account the temporal and spatial distributions of wave power for a period of forty *** this purpose,assimilated wind data of European Centre for Medium-Range Weather Forecasting Interim Reanalysis(ERA-Interim),and hydrography data of General Bathymetric Chat of the oceans(GEBCO)are used as SWAN *** locations are investigated in the study area by considering the amount of coefficient of variation,the amount of average annual power,and the short-term and a new long-term(decadal variability index)power stability assessment *** results showed more stability in the eastern parts of the study area and concluded that a narrow line between the point which is in the middle and another point which is in the eastern middle part of the study area may be the best locations for more investigation and the feasibility study for energy converter ***,it is found that the middle part of the study region with about 2.5 kW/m power is the most energetic *** is concluded that the dominant direction of wave power distribution in all points is the northeast,and this dominant direction has not changed during the forty-year *** is observed that the mean annual energy increases with a slight slope in the total 40 a,and this increasing trend is more obvious in the fourth *** it is observed that the wave power of the second decade has the most stability and the least variation,the wave power in the fourth decade has the most ***,the results showed that the study region’s wave power increase by approximately a mean change rate of 0.027 kW/(m·a);and the maximum change rate of wave power was in the northwest part and the minimum change rate of wave power was in the southeast part which were about 0.036 kW/(m·a)and 0.014 kW/(m·a),respectively.

关键词： wave energy SWAN model wind assimilated data Persian Gulf numerical modeling decadal assessment

Hot Extrusion Process Effect on Mechanical Behavior of Stir Cast Al Based Composites Reinforced with Mechanically Milled B_4C Nanoparticles

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Journal of Materials Science & Technology 2011年第12期27卷 1113-1119页

作者： A. alizadeh E. Taheri-Nassaj M. Hajizamani Department of Materials Science and Engineering Tarbiat Modares University Faculty of Materials and Manufacturing Processes MUT University

In this study, aluminum alloy （Al-2 wt% Cu） matrix composites reinforced with I, 2 and 4 wt% boron carbide nanoparticles fabricated through mechanical milling with average size of 100 nm were fabricated via stir casting method at 850℃. Cast ingots of the matrix alloy and the composites were extruded at 500℃ at an extrusion ratio of 10：1 to investigate the effects of hot extrusion on the mechanical properties of the composites. The microstructures of the as-cast and the extruded composites were investigated by scanning electron microscopy （SEM）. Density measurement, hardness and tensile tests were carried out to identify the mechanical properties of the composites. The extruded samples revealed a more uniform distribution of B4C nanoparticles. Also, the extruded samples had strength and ductility values superior to those of the as-cast counterparts. In the as-cast and the extruded samples, with increasing amount of B4C nanoparticles, yield strength and tensile strength increased but e^ongation to fracture decreased.

关键词： Stir casting Hot extrusion Al matrix composite B4C nanoparticles Mechanicalmilling

Application of artificial neural network to predict Vickers microhardness of AA6061 friction stir welded sheets

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Journal of Central South University 2016年第9期23卷 2146-2155页

作者： vahid Moosabeiki Dehabadi Saeede Ghorbanpour Ghasem Azimi Department of Mechanical Engineering K.N.Toosi University of Technology Educational Workshop Center Isfahan University of Technology

The application of friction stir welding(FSW) is growing owing to the omission of difficulties in traditional welding processes. In the current investigation, artificial neural network(ANN) technique was employed to predict the microhardness of AA6061 friction stir welded plates. Specimens were welded employing triangular and tapered cylindrical pins. The effects of thread and conical shoulder of each pin profile on the microhardness of welded zone were studied using tow ANNs through the different distances from weld centerline. It is observed that using conical shoulder tools enhances the quality of welded area. Besides, in both pin profiles threaded pins and conical shoulders increase yield strength and ultimate tensile strength. Mean absolute percentage error(MAPE) for train and test data sets did not exceed 5.4% and 7.48%, respectively. Considering the accurate results and acceptable errors in the models' responses, the ANN method can be used to economize material and time.

关键词： friction stir welding artificial neural network aluminum 6061 alloy Vickers microhardness

Climate change and agriculture:Impacts and adaptive responses in Iran

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Journal of Integrative Agriculture 2018年第1期17卷 1-15页

作者： vahid Karimi Ezatollah Karami Marzieh Keshavarz Department of Agricultural Extension and Education College of AgricultureShiraz University Department of Agriculture Payame Noor University

The impacts of climate change on agriculture are still shadowed with uncertainty. However, climate change is expected to adversely affect Iran＇s agricultural practices through changes in precipitation, temperature and carbon dioxide fertilization. Therefore, adaptation of this sector to the increasing weather events is imperative. This study is aimed to document the likely impacts of climate change on Iran＇s agriculture and the current adaptation efforts made by government and farmers. The review of literature shows that changes in rainfall and water endowments will have significant impacts on crop yield, crops＇ water requirements and income and welfare of farm families. The extent of the changes in yield depends on the crop type, assumptions related to the CO2 fertilization effect, climate scenarios and adaptation abilities. On adaptation, the government＇s efforts have been distinguished in the improving agricultural productivity and irrigation development based on current technology, developing new technologies and policy reforms. Farmers＇ adaptive responses have also been identified. Some conclusions and recommendations are offered to increase the adaptive capacity of farmers and reduce negative impacts of climate change.

关键词： climate change agriculture impacts adaptation Iran

A Risk-based Competitive Bi-level Framework for Operation of Active Distribution Networks with Networked Microgrids

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Journal of Modern Power Systems and Clean Energy 2021年第5期9卷 1121-1129页

作者： Himan Hamedi vahid Talavat Ali Tofighi Reza Ghanizadeh Department of Electrical Engineering Urmia BranchIslamic Azad UniversityUrmiaIran Department of Electrical Engineering Urmia UniversityUrmiaIran Department of Electrical Engineering Pardis BranchIslamic Azad UniversityPardisIran

This paper presents a risk-based competitive bi-level framework for optimal decision-making in energy sales by a distribution company(DISCO)in an active distribution network(ADN).At the upper level of this framework,the DISCO and a rival retailer compete for selling *** DISCO intends to maximize its profit in the competitive ***,it is very important for the DISCO to make a decision and offer an optimal price for attracting customers and winning the *** microgrids(MGs)at the lower level,as the costumers,intend to purchase energy from less expensive sources in order to minimize *** is a bi-level framework with two different *** genetic algorithm is used to solve this *** DISCO needs to be cautious,so it uses the conditional value at risk(CVaR)to reduce the risk and increase the probability of making the desired *** effect of this index on the trade between the two levels is *** simulation results show that the proposed method can reduce the cost of MGs as the costumers,and can enable the DISCO as the seller to win the competition with its rivals.

关键词： Microgrid networked operation bi-level framework risk active distribution networks

A Method for Improving Power Distribution Characteristics of Space Time Block Codes

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China Communications 2020年第6期17卷 223-234页

作者： vahid Abbasi Mahrokh GShayesteh Department of Electrical Engineering Urmia UniversityUrmia 57561-15311Iran Wireless Research Lab. Elec.Eng.Dep.ACRISharif University of TechnologyTehran 11365-9363Iran

Improving power distribution characteristics of space time block codes(STBCs),namely peak to average power ratio(PAPR),average to minimum power ratio(Ave/min),and probability of transmitting"zero"by antenna,makes easier their practical *** this end,this study proposes to multiply full diversity STB C with a non-singular matrix in multiple input multiple output(MIMO)or multiple input single output(MISO)systems with linear or maximum likelihood(ML)*** is proved that the obtained code achieves full diversity and the order of detection complexity does not *** proposed method is applied to different types of *** bit error rate(BER)and power distribution characteristics of the new codes demonstrate the superiority of the introduced ***,lower and upper bounds on the BER of the obtained STBCs are derived for all *** proposed method provides trade-off among PAPR,spectral efficiency,energy efficiency,and BER.

关键词： full diversity linear receiver maximum likelihood peak to average power ratio power distribution space time block codes

An optimization model for synchronous road geometric and pavement enhancements

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Journal of Traffic and Transportation Engineering(English Edition) 2021年第3期8卷 421-438页

作者： Mohammad Mahanpoor Saeed Monajjem vahid Balali Department of Civil Engineering K.N.Toosi University of TechnologyTehranIran Department of Civil Engineering and Construction Engineering Management California State UniversityLong BeachCA 90840USA

A synchronous optimization model for rehabilitation of existing two-way two-lane(TWTL)highways is proposed in this paper considering geometric modification and existing pavement rehabilitation. The rehabilitation process of existing roadways is categorized into geometric design modifications and pavement repairs. These two types of modification apply separately in roadway life-cycle because of the difference in nature of these repairs, which impose an extra cost and time of closure to road users and owners. This paper aims to address the modification of existing highways by a new approach linking the existing pavement condition and geometric configuration changes of the developed roadway to provide the optimum vertical alignment. The proposed procedure depends on various parameters of existing pavement condition, cross-section configuration, traffic volume and composition, and current alignment composure. In the first step, all these dependencies are explained and quantified with separate cost models. For each solution,the overall cost is calculated with a life-cycle cost analysis approach. Finally, a particle swarm optimization(PSO) based model is developed to find the optimum solution. The developed model was applied in two case studies with good and adverse geometric conditions. The results show that there is a critical condition in the roadway segments which have all these conditions:(1) the grade is more than three percent,(2) the grade is following with reverse grade, and(3) decommissioning of the asphalt concrete(or extended to lower layers) exist. The optimum solution in these critical conditions suggests the modification of the geometric configuration before the pavement rehabilitation in order to reduce the overall cost. In the absence of these conditions, the optimum alignment is more analogous with the existing alignment of the highway.

关键词： Transportation engineering Geometric modification Pavement rehabilitation Optimization Sustainability Safety

Local Strain Energy Density Applied to Bainitic Functionally Graded Steels Plates Under Mixed-Mode(Ⅰ+Ⅱ) Loading

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Acta Metallurgica Sinica(English Letters) 2015年第2期28卷 164-172页

作者： H.Salavati Y.alizadeh F.Berto Department of Mechanical Engineering Amirkabir University of Technology Department of Management and Engineering University of Padova

In this paper, the averaged value of the strain energy density （SED） over a control volume is used to predict the critical load of V-notched specimens made of functionally graded steels （FGSs） under mixed-mode loading. The studied FGSs contain ferritic and austenite phases in addition to bainitic layer produced by electroslag remelting. The mechanism- based strain gradient plasticity theory is used to determine the flow stress （yield stress or ultimate stress） of each layer. The Young＇s modulus and the Poisson＇s ratio have been assumed to be constant, while other mechanical properties vary exponentially along the specimen width. The control volume is centered in relation to the maximum principal stress present on the notch edge and assumes a crescent shape. The points belonging to the volume perimeter are obtained numerically. In the present contribution, the effects of notch radius and notch depth on the SED and the critical load are studied. The notch radius varies from 0.2 to 2.0 mm, and the notch depth varies from 5 to 7 ram. By using the SED approach and finite element simulations, the critical load is determined, and the obtained results show a sound agreement with the experimental results.

关键词： Functionally bainitic graded steel Strain energy density Mechanism-based strain gradientplasticity theory Critical load Notch radius Notch depth