Growth Rates Analysis for Pistachio Production and Export in Iran during 1991-2002

Reza Sedaghat 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

ON THE CONSTITUTIVE MODELS FOR ULTRA-HIGH STRAIN RATE DEFORMATION OF METALS

Hossein Sedaghat,Weixing Xu,Liangchi Zhang,Weidong Liu 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.Supp

Ultra-high strain rate deformation (> 104 s1) is common in high speed manufacturing and impact engineering. However, a general constitutive model suitable for describing the material deformation at ultra-high strain rates is still unavailable. The purpose of this study is of two-folds. The first is to systematically evaluate the performances of four typical constitutive models, Johnson-Cook (J-C), Khan-Huang-Liang (KHL), Zerilli-Armstrong (Z-A), and Gao-Zhang (G-Z), in predicting the dynamic behaviors of materials. The second is to obtain an improved constitutive model to better describe the deformation of materials under ultra-high strain rates. To this end, high strain rate tests were carried out on different crystalline structures, i.e., BCC, FCC, and HCP over a wide range of strain rate from 102 s1 to 1.5 × 104 s1. It was found that before the critical strain rate, around 104 s1, all of the previous models can predict the flow stresses. When the strain rate passes a critical point, however, these models fail to predict the sudden upsurge of the flow stresses. The improved model developed in this paper, by considering the dislocation drag mechanism, can successfully characterize the dynamic behaviours of materials over the whole range of strain rates.

Sustainable Irrigation for Pistachio Farms in Iran

Reza Sedaghat 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Shape and Orifice Optimization of Airbag Systems for UAV Parachute Landing

Alizadeh, Masoud,Sedaghat, Ahmad,Kargar, Ebrahim The Korean Society for Aeronautical and Space Scie 2014 International Journal of Aeronautical and Space Sc Vol.15 No.3

An airbag is an important safety system and is well known as a safety system in cars during an accident. Airbag systems are also used as a shock absorber for UAVs to assist with rapid parachute landings. In this paper, the dynamics and gas dynamics of five airbag shapes, cylindrical, semi-cylindrical, cubic, and two truncated pyramids, were modelled and simulated under conditions of impact acceleration lower than $4m/s^2$ to avoid damage to the UAV. First, the responses of the present modelling were compared and validated against airbag test results under the same conditions. Second, for each airbag shape under the same conditions, the responses in terms of pressure, acceleration, and emerging velocity were investigated. Third, the performance of a pressure relief valve is compared with a fixed-area orifice implemented in the air bag. For each airbag shape under the same conditions, the optimum area of the fixed orifice was determined. By examining the response of pressure and acceleration of the airbag, the optimum shape of the airbag and the venting system is suggested.

NUMERICAL SOLUTION OF A CLASS OF TWO-DIMENSIONAL NONLINEAR VOLTERRA INTEGRAL EQUATIONS OF THE FIRST KIND

Abolfazl Tari,Sedaghat Shahmorad 한국전산응용수학회 2012 Journal of applied mathematics & informatics Vol.30 No.3

In this work, we investigate solving two-dimensional nonlinear Volterra integral equations of the first kind (2DNVIEF). Here we convert 2DNVIEF to the two-dimensional linear Volterra integral equations of the first kind (2DLVIEF) and then we solve it by using operational approach of the Tau method. But for solving the 2DLVIEF we convert it to an equivalent equation of the second kind and then by giving some theorems we formulate the operational Tau method with standard base for solving the equation of the second kind. Finally, some numerical examples are given to clarify the efficiency and accuracy of presented method.

ON EVOLUTION OF FINSLER RICCI SCALAR

Bidabad, Behroz,Sedaghat, Maral Khadem Korean Mathematical Society 2018 대한수학회지 Vol.55 No.3

Here, we calculate the evolution equation of the reduced hh-curvature and the Ricci scalar along the Finslerian Ricci flow. We prove that Finsler Ricci flow preserves positivity of the reduced hh-curvature on finite time. Next, it is shown that evolution of Ricci scalar is a parabolic-type equation and moreover if the initial Finsler metric is of positive flag curvature, then the flag curvature, as well as the Ricci scalar, remain positive as long as the solution exists. Finally, we present a lower bound for Ricci scalar along Ricci flow.

Synthesis and Characterization of a Novel Organotin Complex: Di(n-butyl) chloro[5-(p-dimethylaminobenzylidene)rhodanine]tin(IV) Based on a Competing N, O, and S Donor Ligand

Tarassoli, Abbas,Sedaghat, Tahereh,Mousavi, Fatemeh Korean Chemical Society 2011 대한화학회지 Vol.55 No.4

새로운 유기주석(IV) 착물을 $Bu_2SnCl_2$과 N, O 및 S 주개 리간드인 5-(p-dimethylaminobenzylidene)rodanine(HL)로 부터 제조하였다. 염기 존재 하에 리간드는 탈양성자화되며, SnBuCl2L의 분자식을 갖는 착물이 형성되었다. 이 착물은 IR, $^1H$ NMR, $^{119}Sn$ NMR 및 원소분석을 통하여 전반적으로 특성을 분석하였다. 분광학적인 데이터로부터 리간드는 산소원자를 통하여 주석에 배위됨을 알았으며, 배위수가 4임을 용액에서 $^{119}Sn$ NMR 데이터에 의해 결정하였다. A novel organotin(IV) complex has been prepared from $Bu_2SnCl_2$ and the N, O and S donor ligand, 5-(p-dimethylaminobenzylidene) rodanine (HL). The ligand is deprotonated in the presence of a base and the complex with the general formula $SnBuCl_2L$ is formed. This complex was fully characterized by IR, $^1H$ NMR and $^{119}Sn$ NMR and elemental analysis. Spectroscopic data indicate the ligand is coordinated through the oxygen atom to the tin and the coordination number of four is supported by $^{119}Sn$ NMR data in solution.

Localization of solar-hydrogen power plants in the province of Kerman, Iran

Mostafaeipour, Ali,Sedaghat, Ahmad,Qolipour, Mojtaba,Rezaei, Mostafa,Arabnia, Hamid R.,Saidi-Mehrabad, Mohammad,Shamshirband, Shahaboddin,Alavi, Omid Techno-Press 2017 Advances in energy research Vol.5 No.2

This research presents an in-depth analysis of location planning of the solar-hydrogen power plants for electricity production in different cities situated in Kerman province of Iran. Ten cities were analyzed in order to select the most suitable location for the construction of a solar-hydrogen power plant utilizing photovoltaic panels. Data envelopment analysis (DEA) methodology was applied to prioritize cities for installing the solar-hydrogen power plant so that one candidate location was selected for each city. Different criteria including population, distance to main road, flood risk, wind speed, sunshine hours, air temperature, humidity, horizontal solar irradiation, dust, and land costare used for the analysis. From the analysis, it is found that among the candidates' cities, the site of Lalezar is ranked as the first priority for the solar-hydrogen system development. A measure of validity is obtained when results of the DEA method are compared with the results of the technique for ordering preference by similarity to ideal solution (TOPSIS). Applying TOPSIS model, it was found that city of Lalezar ranked first, and Rafsanjan gained last priority for installing the solar-hydrogen power plants. Cities of Baft, Sirjan, Kerman, Shahrbabak, Kahnouj, Shahdad, Bam, and Jiroft ranked second to ninth, respectively. The validity of the DEA model is compared with the results of TOPSIS and it is demonstrated that the two methods produced similar results. The solar-hydrogen power plant is considered for installation in the city of Lalezar. It is demonstrated that installation of the proposed solar-hydrogen system in Lalezar can lead to yearly yield of 129 ton-H2 which covers 4.3% of total annual energy demands of the city.

Increasing Flight Endurance of MAVs using Multiple Quantum Well Solar Cells

Hassanalian, Mostafa,Radmanesh, Mohammadreza,Sedaghat, Ahmad The Korean Society for Aeronautical and Space Scie 2014 International Journal of Aeronautical and Space Sc Vol.15 No.2

Micro Aerial Vehicles (MAVs) are useful devices to assess new features that may be utilized in a full size aircraft to enhance performance or to increase endurance. In this article, sources for energy saving in the micro air vehicles are initially addressed. Then, by specifying the important parameters on energy consumption of an aircraft, a feasibility study is conducted to assess the benefit of using solar cells to increase flight endurance. Next, a new solar cell has been designed and optimized for MAVs. This cell consists of a multiple quantum wells for which the quantum factor and the absorption coefficient are calculated by solving the Shrodinger equation using MATLAB software. Then, the manner and influence of MAVs parameters using the solar cells are examined to suggest optimal planform for different purposes. In order to increase flight endurance, it is noted that by using appropriate planform and the optimized solar cells, flight endurance can be increased by more than 30 percent.

On the origin of viscoelastic Taylor–Couette instability resulted from normal stress differences

Mahmood Norouzi,M.H. Sedaghat,M.M. Shahmardan,M.R.H. Nobari 한국유변학회 2015 Korea-Australia rheology journal Vol.27 No.1

In this paper, the effect of normal stress differences on the viscoelastic Taylor–Couette instability is studied numerically. The governing equations are discretized using FTCS finite difference method on a staggered mesh based on the artificial compressibility algorithm. Using the CEF model as the constitutive equation and the Carreau–Yasuda model as the viscometric functions, the flow between rotating cylinders has been studied for a range of radius ratios, Taylor numbers and rheological properties. It is shown that increasing the first normal stress difference destabilizes the flow field while increasing the negative second normal stress difference stabilizes the flow field. The main contribution of the current study is an answer to thisquestion: How do the first and second normal stress differences affect the stability of viscoelastic flowbetween rotating cylinders? For this reason, we used the order of magnitude technique to obtain a force balancerelation in the core region of flow. Based on this relation and numerical simulation, the origin of viscoelasticTaylor–Couette instability resulted from normal stress differences are studied in detail. Furthermore, a two dimensional analytical solution for the main flow velocity component between finiterotating cylinders is carried out considering the end effect of stationary walls