Seismic assessment of Nitinol Belleville Elastic Nonlinear (NI-BELL-E-N) structural system

Alireza Asgari Hadad,Bahram M. Shahrooz 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.43 No.3

Nibellen structural system is a novel resilient bracing system based on the application of Bellville disks and Nitinol rods. The cyclic behavior of Nibellen assembly was obtained, and the design equations were developed based on the available literature. Seismic performance of the system was then studied analytically. Two groups of buildings with different lateral force resisting systems were designed and studied: one group with the Nibellen system, and the other with the special concentrically braced frame system. Each building group consisted of 5-, 10-, and 15-story buildings. The Design-Base-Event (DBE) and Maximum Considered Event (MCE) were considered as the seismic hazard, and a suite of seven ground motions were scaled accordingly for response history analyses. Finally, the resiliency of the buildings was studied by obtaining the functionality curve of the buildings before and after the seismic event. The construction cost of the 5-story building with Nibellen bracing system increased but the post-earthquake cost decreased significantly. The application of Nibellen system in the 10- and 15-story buildings reduced both the construction and repair costs, considerably. Resiliency of all the buildings was improved when Nibellen system was used as the lateral force resisting system.

Multi-objective optimization of tapered tubes for crashworthiness by surrogate methodologies

Masoud Asgari,Alireza Babaee,Mohammadamin Jamshidi 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.27 No.4

In this paper, the single and multi-objective optimization of thin-walled conical tubes with different types of indentations under axial impact has been investigated using surrogate models called metamodels. The geometry of tapered thin-walled tubes has been studied in order to achieve maximum specific energy absorption (SEA) and minimum peak crushing force (PCF). The height, radius, thickness, tapered angle of the tube, and the radius of indentation have been considered as design variables. Based on the design of experiments (DOE) method, the generated sample points are computed using the explicit finite element code. Different surrogate models including Kriging, Feed Forward Neural Network (FNN), Radial Basis Neural Network (RNN), and Response Surface Modelling (RSM) comprised to evaluate the appropriation of such models. The comparison study between surrogate models and the exploration of indentation shapes have been provided. The obtained results show that the RNN method has the minimum mean squared error (MSE) in training points compared to the other methods. Meanwhile, optimization based on surrogate models with lower values of MSE does not provide optimum results. The RNN method demonstrates a lower crashworthiness performance (with a lower value of 125.7% for SEA and a higher value of 56.8% for PCF) in comparison to RSM with an error order of 10^-3. The SEA values can be increased by 17.6% and PCF values can be decreased by 24.63% by different types of indentation. In a specific geometry, higher SEA and lower PCF require triangular and circular shapes of indentation, respectively.

Biodiversity status of Tulipa (Liliaceae) in Iran inferred from molecular characterization

Davoud Asgari,Alireza Babaei,Mohammad Reza Naghavi,Mahmoud Kiani 한국원예학회 2020 Horticulture, Environment, and Biotechnology Vol.61 No.3

Here, we used data generated from amplifi ed fragment length polymorphism (AFLP) analysis to address the biodiversitystatus and taxonomic relationships among 47 wild accessions representing 9 species of the genus Tulipa in Iran. A high levelof genetic diversity within the genus was observed; the most distant taxa were T. humilis and T. schrenkii , while the highestdegree of similarity was found between T. montana and T. bifl ora . Twelve AFLP primer sets amplifi ed 342 fragments, ofwhich 304 were polymorphic (88.1%). The average number of polymorphic bands per AFLP primer pair was 28.5. A hierarchicalcluster analysis was carried out on the genetic profi le of the taxa, and the results mostly reconfi rmed the recognizedtaxonomy of the genus. However, we found evidence for recognition of a new subgenus for T. biebersteiniana .

Modeling the impact of logistic performance, economic features, and demographic factors of countries on the seaborne trade

Mahpour Alireza,Farzin Iman,Baghestani Amirhossein,Ashouri Sina,Javadi Zahra,Asgari Latifeh 한국해운물류학회 2023 The Asian journal of shipping and Logistics Vol.39 No.2

The shipping industry continues to have strong growth prospects due to increased efficiency and economic liberalization. Through seaborne trade, port infrastructure and logistics impact economic growth in developing countries. This makes studying the factors affecting seaborne trade for such countries particularly important. The current paper aims at analyzing the impact of logistics, economic, and demographic variables on seaborne commodity trade between Qatar, Oman, Turkey, Pakistan, and Iran. Employing a gravity model, results show that a 1% improvement in Logistics Performance Index (LPI) consignments in the importing country can result in a 0.8% increase in total trade flows. Based on results, a 1% increase in the tariff rate reduces the value of trade by 0.4%. Furthermore, a 0.5% increase in trade is caused by the increase in population of the destination country. A sensitivity analysis also shows that logistics variables are more significant than economic and demographic variables. It can be concluded that trade policymakers in developing countries can get better results by improving logistics performance and investing on logistics infrastructure leads to more trade.

Study on The Bearing Trends of Apple cv. ‘Golden Smoothee’ on Four Clonal

Ali Gharaghani,Alireza Talaie,Mohammadali asgari 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Study of cracks in compressed concrete specimens with a notch and two neighboring holes

Vahab, Sarfarazi,Kaveh, Asgari,Shirin, Jahanmiri,Mohammad Fatehi, Marji,Alireza Mohammadi, Khachakini Techno-Press 2022 Advances in concrete construction Vol.14 No.5

This paper investigated computationally and experimentally the interaction here between a notch as well as a micropore under uniaxial compression. Brazilian tensile strength, uniaxial tensile strength, as well as biaxial tensile strength are used to calibrate PFC2d at first. Then, uniaxial compression test was conducted which they included internal notch and micro pore. Experimental and numerical building of 9 models including notch and micro pore were conducted. Model dimensions of models are 10 cm × 10 cm × 5 cm. Joint length was 2 cm. Joints angles were 30°, 45° and 60°. The position of micro pore for all joint angles was 2cm upper than top of the joint, 2 cm upper than middle of joint and 2 cm upper than the joint lower tip, discreetly. The numerical model's dimensions were 5.4 cm × 10.8 cm. The fractures were 2 cm in length and had angularities of 30, 45, and 60 degrees. The pore had a diameter of 1 cm and was located at the top of the notch, 2 cm above the top, 2 cm above the middle, and 2 cm above the bottom tip of the joint. The uniaxial compression strength of the model material was 10 MPa. The local damping ratio was 0.7. At 0.016 mm per second, it loaded. The results show that failure pattern affects uniaxial compressive strength whereas notch orientation and pore condition impact failure pattern. From the notch tips, a two-wing fracture spreads almost parallel to the usual load until it unites with the sample edge. Additionally, two wing fractures start at the hole. Both of these cracks join the sample edge and one of them joins the notch. The number of wing cracks increased as the joint angle rose. There aren't many AE effects in the early phases of loading, but they quickly build up until the applied stress reaches its maximum. Each stress decrease was also followed by several AE effects. By raising the joint angularities from 30° to 60°, uniaxial strength was reduced. The failure strengths in both the numerical simulation and the actual test are quite similar.

Tissues toxicity attenuation by vitamin E on oxidative damage induced by diazinon

Kavoos Tahmasebi,Mahvash Jafari,Javad Heydari,Alireza Asgari,Maryam Salehi,Saeed Khazaie,Mohammad Saleh Abedini 5 환경독성보건학회 2022 환경독성보건학회지 Vol.37 No.4

Organophosphorus insecticides such as diazinon (DZN) are used worldwide in industry, veterinary practice, and agriculture. They may induce oxidative stress in different tissues. The use of antioxidants can protect tissues against oxidative stress. The aim of this study was to investigate the prophylactic and therapeutic roles of vitamin E against DZN–induced oxidative damage and biochemical alterations in various tissues of male Wistar rats. Thirty rats were divided into five groups: Control group received only corn oil as DZN solvent, DZN group received 100 mg/kg of DZN, E group received 150 mg/kg of vitamin E, E-DZN group received vitamin E and then dosed with DZN and DZN-E group received DZN and then dosed with vitamin E. All injections were carried out intraperitoneally. Plasma and various tissues were prepared and evaluated. Results showed that acute administration of DZN caused a significant induction of oxidative damage in the tested tissues via increased malondialdehyde level and some plasma biochemical indices, depletion of glutathione (GSH), reduced cholinesterase activity and change in the activities of superoxide dismutase, catalase and glutathione-S transferase. Treatment of rats with vitamin E resulted in an elevation in the level of GSH, normalizing the antioxidant enzymes activities and decreasing lipid peroxidation, although all these tests did not return to the normal level in certain tissues. The findings of this study suggest that both prophylactic and therapeutic treatments of rats with vitamin E provide a protective role against DZN-induced oxidative stress and cholinergic hyperactivity through free radicals scavenging and membrane stabilizing.

Design of ionic liquid 1,3-disulfonic acid imidazolium hydrogen sulfate as a dual-catalyst for the one-pot multi-component synthesis of 1,2,4,5-tetrasubstituted imidazoles

Mohammad Ali Zolfigol,Ardeshir Khazaei,Ahmad Reza Moosavi-Zare,Abdolkarim Zare,Zhila Asgari,Vahid Khakyzadeh,Alireza Hasaninejad 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.3

Novel ionic liquid 1,3-disulfonic acid imidazolium hydrogen sulfate {[Dsim]HSO4} efficiently catalyzes the synthesis of 1,2,4,5-tetrasubstituted imidazoles via the one-pot multi-component condensation of benzyl with aldehydes, primary amines and ammonium acetate at 90 8C under solvent-free conditions. Dual hydrogen-bond donors can be used to direct the assembly of this catalyst and the efficiency of it.