Showing 4 results for Faghani
S.a.a. Akbari Mousavi , Gh. Faghani, H.r. Sheivani,
Volume 20, Issue 2 (February 2020)
Abstract
One of the emerging methods of joining various metals is the use of laser beam welding in a variety of industries such as transportation, aerospace, radar, and marine construction, which reduces fuel consumption and thus reduces environmental pollution. In this study, the microstructure and mechanical properties of similar joints of aluminum alloy 6061 with a thickness of 2 millimeters have been investigated by the laser beam welding method with a high power of 5000 watts. Examined items include the effect of laser welding parameters such as power, frequency, and welding speed on microstructural and mechanical properties. Microstructural analysis results using an optical and scanning electron microscope show that in the process, the microstructure of the weld in the base metal to the center of the weld region changed from the dendritic column to the parallel dendritic zone and eventually reached the equiaxed dendritic area, due to the higher input temperature and consequently less cooling rate. Energy-dispersive X-ray spectroscopy (EDS) showed no significant change in the chemical composition. Investigating the mechanical properties using hardness measurement, and the tensile testing showed that the hardness in the fusion zone was lower than other base metal zones, and the optimized sample was failed in the weld zone. The tensile strength of the optimum welding sample is approximately equal to half the tensile strength of the base metal.
Volume 24, Issue 6 (11-2022)
Abstract
This research was carried out to provide suitable cotton seed for seed propagation in dryland. In this study, the potential of cotton seeds that have been stressed for the third-consecutive year was investigated to evaluate water stress memory responses. The experiment was arranged in split-plot factorial design with four irrigation levels of W0 (No- irrigation), W1 (33% FC), W2 (66% FC), and W3 (100% FC), as the main factor, and five seed treatments (four third-stressed seeds, i.e. S21 to S24, and registered seed), as a sub-plot. Seeds of cotton were grown under different levels of water-stress exposure for three crop-seasons. As results showed, S32 received water stress signal in both W0 and W3 conditions through physiological mechanisms change. Seeds of S32 accumulated the lowest ABA and the highest calcium in exposure to W0 and W3. Enhancement to superoxide dismutase and Aspartate peroxidase activity in leaves of S32 in exposure to W0 and W1 is another memorial stress mechanism for scarce water acclimation. The highest-potential thirty-boll weight, thirty-fiber weight, and first-harvesting yield were obtained from S32 against W0, W1, and W2.. Also, the seeds of S32 had the most seedling vigor and germination percentage in exposure to W0, W1, and W2. It can be concluded that stress memory, via modification of physiology and morphology of plant behavior, helps plants to tolerate water deficiency when subjected to recurrent drought.
Volume 25, Issue 2 (2-2023)
Abstract
Expansion of salt stress in cultivable fields prevents plant physiological functions and reduces crop yield. Arbuscular Mycorrhizal Fungi (AMF), as a bio-amelioration of salt stress, protects cellular osmosis via disaccharide and polysaccharide metabolism changes. In this study, three Gossypium species (i.e., G. hirsutum, G. barbadense, and G. herbaceum) colonized with Rhizophagus intraradices [with AMF and without AMF] were cultivated under saline irrigation treatments (ECe< 4 Ds m-1= S0, 8-9= S1, and 12-13= S2) as a factorial experiment. Salinity treatments were initiated at flowering. Generally, according to physiological traits, [+AMF] colonized with G. barbadense was more tolerant in exposure to 12-13 dS m-1 salinity, while G. hirsutum with [+AMF] was just tolerant until 8-9 dS m-1. This is because, the highest and the least leaf area were observed in G. barbadense [+AMF] under 8-9 and 12-13 dS m-1, respectively. In 12-13 dS m-1, the highest root volume, root dry weight, seed weight, and fiber weight were obtained in G. barbadense [+AMF]. Moreover, the highest sugar content in root and leaves and the highest starch content of root, leaves, and seed cotyledon were observed in G. barbadense [+AMF] under 12-13 dS m-1 treatment. Under 8-9 dS.m-1 salinity, the highest starch, Sucrose Phosphate Synthase (SPS) and Sucrose Phosphatase (SP) enzyme activities were in roots of G. barbadense [+AMF]. The present study suggests that despite dramatic physiological alterations under high-salinity in comparison with mild-salinity, AMF and G. barbadense showed the best symbiotic performance under 12-13 dS m-1.
Volume 25, Issue 3 (5-2023)
Abstract
Participation in collective actions refers to an individual's behavioral, mental, and emotional engagement in group-situations that motivates him or her to achieve group goals, including environmental protection. The present study aimed at analyzing the intention of members of environmental NGOs to participate in collective pro-environmental activities. To do this, the psychological Dual-pathway Model of Collective Action (DMCA) was used. The research method was descriptive-correlational and was done using survey technique. The statistical population included members of the pro-environmental NGOs in Tehran Province, Iran (N= 680). Out of the population, 248 cases were selected as a sample using stratified random sampling method with proportional assignment. The research instrument was a researcher-made questionnaire and its validity was verified using a panel of case experts and AVE index. Besides, the reliability was confirmed using Cronbach's alpha coefficients, principal component analysis, and composite reliability indices. According to the DMCA, the effects of Perceived Behavioral Control variables about Collective Pro-Environmental Activities (PBCCPEA), Attitude towards Participation in Collective Pro-Environmental Activities (APCPEA), Subjective Norms about Participation in Collective Pro-Environmental Activities (SNPCPEA), Social Identity about Participation in Collective Pro-Environmental Activities (SIPCPEA) were tested on Intention towards Participation in Collective Pro-Environmental Activities (IPCPEA). The results show that this model is able to explain 66% of the variance of IPCPEA changes. The results of this study indicate the need for special attention from the perspective of collective action to make significant changes in the creation of IPCPEA.
