Showing 4 results for Shaghaghi
Volume 0, Issue 0 (In press 2023)
Abstract
The purpose of the research is to analyze and apply the physical resilience of housing in dilapidated urban textures in the neighborhoods of region 7 with 13 neighborhoods with an area of 1970383 square meters, as well as its impact on the sustainability of urban resources. The present research is an applied-developmental type and a descriptive-analytical method and evaluates the physical resilience of housing in the studied area with data from documentary studies available in the Housing and Urban Development Organization, the Center for Statistics and Municipality. Data have been extracted and categorized in terms of building skeleton, building age, and permeability, number of floors, material type, building quality, and particle size distribution in residential fabric. In order to evaluate and discover the pattern of regression tools, spatial autocorrelation method for weighting layers, spatial distribution analysis using Anselin local Morans autocorrelation method in GIS and Geoda software has been used at the levels of neighborhoods in region 7. The results indicate that despite the larger area of the area being in the medium to non-resilient resilience range in terms of separation, the resilience spectrum in neighborhoods is facing different changes and impacts, and its geographical distribution is more evident in the eastern part of the region.
Volume 14, Issue 14 (Second Special Issue 2015)
Abstract
To investigate, understanding and predicting dynamic fracture behavior of a cracked body, dynamic stress intensity factors (DSIFs) are important parameters. In the present work interaction integral method is presented to compute static and dynamic stress intensity factors for three-dimensional cracks contained in the functionally graded materials (FGMs), and is implemented in conjunction with the finite element method (FEM). By a suitable definition of the auxiliary fields, the interaction integral method which is not related to derivatives of material properties can be obtained. For the sake of comparison, center, edge and elliptical cracks in homogeneous and functionally graded materials under static and dynamic loading are considered. Then material gradation is introduced in an exponential form in the two directions in and normal to the crack plane. Then the influence of the graded modulus of elasticity on static and dynamic stress intensity factors is investigated. It has been shown that, material gradation has considerable reduce influence on DSIFs of functionally graded material in comparison with homogenous material. While, static stress intensity factors can decrease or increase, depend on the direction of gradation material property.
Volume 15, Issue 9 (11-2015)
Abstract
The objective of the present work is to investigate indentation in polymers and hyperelastic materials. Both experiments and numerical analysis have been carried out. Two different sports floorings were selected to test, monolayer rubber and two layer polyurethane (PU)/polyvinylchloride (PVC). To determine the value of hardness and indentation depth of indenter in the materials, experimental study was carried out according to quality standard test for sports flooring. The numerical analysis was also conducted by Abaqus software using simulation of experimental testing conditions, selection of the best hyperelastic model and comparison of the results to experimental test in order to ascertain the efficiency and accuracy of each simulation step. The accuracy of the results has been shown by comparision of experiments with numerical results. For the first sample, indentation depth was 0.575 mm (based on experimental result) and Yeoh’s model was employed to simulate with the error of 4.3%. The indentation depth and error (by selection of reduced polynomial form of order two models) were 0.425 mm and 0.94%. for the second sample (PU/PVC), respectively. In addition, hardness was decreased from 78.1 to 75.3 when the thickness of rubber sports flooring was increased from 2.5 to 5 mm. In general, it can be concluded that the hardness values of polymers depend on their thickness, and on the other hand the indenter shape has influence on indentation depth and force-displacement curves, as well.
Shahin Zomorodi, Farid AmirShaghaghi, Karim Gerami,
Volume 19, Issue 127 (September 2022)
Abstract
Raisin is one of the important export products in the agricultural sector, but there are several challenges in increasing the quality of raisins and their competition in foreign markets. The type of drying place and environmental conditions can have a great impact on the quality of raisins. In this study, the aim is to modify the traditional grape drying place, using intelligent heating plates. The seedless grape was harvested at two different times and prepared by two methods, natural (without pretreatment) and treated with alkaline solution and dried in traditional place with concrete floor and traditional place modified by control heating plates. The results showed that the drying time of non-treated raisins was 2.36 times of alkali-treated raisins and the drying time of traditional place was about 4.75 times of modified place. Also, the total count, coliform, molds and yeasts in the traditional drying place were higher, but the number of lactic acid bacteria was less than the modified method (P <0.05). In alkali-treated raisins, the total count, coliform and mold were lower, but the number of lactic acid bacteria and yeasts was higher than natural raisins (P <0.05). The results of sensory evaluation also showed that the color score of samples with alkali-treated raisins was significantly higher than other. The amount of energy consumed to prepare one kg of raisins in 21th September and 12th October was 0.98 and 1.78 kWh, respectively, and for natural raisins, this amount was 1.63 and 5.5 kWh, respectively. According to the results obtained in this study, it is possible to prepare raisins with high hygienic quality and desirable sensory properties by harvesting grapes in a timely and drying in the place with intelligent heating plates