Showing 12 results for Ahmadifar
Volume 0, Issue 0 (Articles accepted at the time of publication 2024)
Abstract
This study explores how Lacanian psychoanalysis governs and understands the mother-child relationships in Tennessee Williams' The Glass Menagerie (1944/2014) and Darren Aronofsky’s Black Swan (2010). In so doing, the primary purpose of this study has been to establish the links between the central characters' behaviors and the psychoanalytic concept of 'deferral of desire’.' The research proposes a novel aspect of 'psychoanalytic meaning' by basing it on the counter-intuitive process of evading the jouissance of actualizing and immersing oneself in one's object of desire. To support the proposition mentioned above, this study has explored the eventual fate of the children in Black Swan (Nina), and The Glass Menagerie (Tom and Laura), analyzing their respective experiences of (dis)satisfaction after their ultimate success or failure in their attempts to attain their objects of desire. This study has employed the Lacanian psychoanalytic concepts of the objet petit a and register theory to posit that satisfaction lies not in obtaining one’s object of desire, but in repeatedly failing to do so, due to the fact that possessing the object of desire shatters the lack which is the necessary condition of maintaining the desirability of the object of desire. The article concludes that while we are intuitively equipped to think of satisfaction as the effect of the realization of the object of one's desire, psychoanalytically speaking, satisfaction is found in precisely the opposite direction, that is, in a repeated failure to obtain the object of one's desire.
Volume 0, Issue 0 (ARTICLES IN PRESS 2024)
Abstract
Rural handwoven carpet weavers, particularly in the context of handmade silk carpet production, grapple with significant challenges concerning recognizing all stakeholders and establishing timely connections. These challenges have a substantial impact on the adoption of innovation in carpet production and the overall enhancement of productivity. This research was conducted to scrutinize the communication network of carpet weavers within the Knowledge and Innovation System (KIS) of handmade silk carpet production in rural areas. Data were gathered through interviews with 270 rural households in Zanjan province, specifically in the Tarom, Khodabandeh, and Zanjan counties, utilizing a structured questionnaire. Social Network Analysis (SNA) in UCINET was employed to examine the interactions among these actors, and graphical representations were created using Net Draw. The results revealed that the network's density varied across different levels, showing weakness in some cases, moderate strength in others, and strong connections in select instances. The connections of carpet weaving families with other actors within the KIS were predominantly localized. Among these families, those utilizing the home-based wage production method exhibited the most extensive interactions. The individuals designated as "FMs" (likely referring to family members) and "WNVKRs" (possibly local experts) demonstrated the highest degree of connection and influence within the network of weavers' interactions
Volume 7, Issue 3 (Summer 2018)
Abstract
Aims: Artemia is one of the most important live foods in aquaculture. The aim of the current study was to investigate Microbiota of Artemia franciscana fed by bacterial probiotic Bacillus subtilis and yeast Saccharomyces cerevisiae under laboratory conditions.
Materials and Methods: In this experimental research, 500 Artemia nauplius were transported to 1 liter Zug with salinity of 70ppt and fed daily by Dunaliella tertiolecta and wheat bran. The present study was carried out in 4 treatments, including control treatment (no additive probiotics), probiotic treatment of Saccharomyces cerevisiae, probiotic treatment of Bacillus subtilis, and equal combination of yeast and bacteria. Statistical tests including Duncan's new multiple range test and one-way analysis of variance were used. SPSS 21 and Excel 2013 software were also used.
Findings: Bacterial probiotic treatment showed the highest colony count compared with other treatments (p<0.05). Treatment containing equal combination of yeast and bacteria had the highest colony after probiotic bacterial treatment (p<0.05). The highest number of Bacillus colonies in the body was obtained in probiotic bacterial treatment and combination of yeast and bacteria, respectively, which was significantly higher than control and yeast treatments (p<0.05). Based on the total number of Bacillus colonies, probiotic bacterial treatment showed a significant difference with other treatments and the lowest number of colony was related to probiotic yeast treatment (p<0.05).
Conclusion: Compared with other treatments, the highest number of lactic acidic bacteria is in bacterial treatment. These probiotics can well place on the surface as well as inside the body of Artemia. Therefore, using Bacillus subtilis alone or with Saccharomyces cerevisiae can have a positive effect on the bacterial count of Artemia
Volume 10, Issue 3 (9-2021)
Abstract
Despite the positive role of rotifers in many hatcheries for feeding the early stages of aquatic larvae, the lower mineral content of zinc (Zn) is one of the disadvantages of rotifer compared to copepods. Therefore, it is necessary to increase its amounts through enrichment. For this purpose, in the present study, a combination of algae Isochrysis aff. galbana and Nannochloropsis oculata were enriched with zinc sulfate for 1 and 3 hours. Due to obtaining better results in 1 hour, its effects on the growth and enrichment of rotifer were surveyed. The 1: 1 alga composition was enriched with zinc sulfate at concentrations (45, 90, and 135 mg/l). The highest amount of zinc was observed in the mixed algal enriched with 90 mg/l for 1 h, which had the highest copper amount and there was no significant difference with the control group. Also, the manganese amount was higher than the other treatments except for the control group. After feeding the rotifers with enriched algae for 1 hour, the best treatment was 45 mg/l, which also contained the second level of zinc and the first level of manganese, copper, potassium, and sodium. On the other hand, this treatment had the highest number of eggs on the peak day of reproduction treatments (third day) and its population density in the last days was not significantly different from the control group (p <0.05). Zn-enriched rotifers can be used to feed marine fish to meet the nutritional needs of aquatic larvae.
Volume 10, Issue 4 (12-2021)
Abstract
In the present study, the effect of phytohormone gibberellin on some physiological parameters of Tetraselmis suecica microalgae was investigated. Algae culture was performed under standard conditions with Gillard culture medium, temperature 25 ± 2 C°, light intensity 16: 8 (light/dark), salinity 25 ± 2 mg / l, and 24-hour aeration for ten days. Concentrations of 10, 20, 40, and 60 mg / l were added to the algae culture medium. Growth factors, pigments, photosynthetic factors, and biochemical composition were measured in the log phase. Based on results, the highest rate of cell growth was observed in the treatment of 60 mg / l, although in other treatments there was a significant difference with the control (P <0.05). The highest amount of protein and carbohydrates was observed in the treatment of 60 mg / l (P <0.05). ). Total lipid content increased from 15.23 in control to 18.53 in 60 mg / l (P <0.05). Antioxidant potential, pigments, photosynthetic factors, and dry weight also showed a significant difference in the concentration of 60 mg / l compared to the control (P <0.05). The highest amount of chlorophyll a and chlorophyll b was observed at concentrations of 60 mg / l (P <0.05). Based on the results, gibberellin has a high potential for cell division, final density, antioxidant potential, cell size, and biochemical composition of Tetraselmis suecica. Also, Tetraselmis suecica can be a good candidate for marine aquatic larvae, drugs, antioxidants, and a rich source of compounds in biofuels.
Volume 13, Issue 2 (6-2024)
Abstract
Agricultural effluents contain nutrients such as phosphates, nitrates and ammonia, which cause surface and underground water pollution. By absorbing these nutrients, freshwater algae such as Spirulina can play an important role in reducing these types of pollutants. On the other hand, this type of wastewater, having nutrients, can be used as an alternative and cheap substrate for algae cultivation. Five concentrations of diluted sugarcane effluent (0, 25, 50, 75, and 100%) were prepared with Zarrouk’s medium and the growth rate, photosynthetic pigments, and the amount of some mineral substances, protein, and fat composition were evaluated. In high concentrations of wastewater (75 and 100% wastewater treatment), a very good growth of Spirulina was observed.The amount of chlorophyll a in the treatment of 100% of wastewater showed a significant increase compared to the control treatment (p < 0.05). The maximum amount of total carotenoids in the treatment of 50% of the Zarrouk’s medium was obtained at the rate of 1559 ± 226 mg/liter, which was more than 2 times the amount of total carotenoids in the control treatment. The maximum amount of total carotenoid in the treatment of 50% of Zarrouk’s medium was 1559 ± 226 mg/liter, which was more than 2 times the amount of total carotenoid in the control treatment.In addition, the produced algae can be used as livestock and aquatic food.
Saeed Ahmadifard, Masoud Roknian, Taleb Tinati Seresht, Shahab Kazemi,
Volume 16, Issue 6 (8-2016)
Abstract
Hybrid ratio of each reinforcement phases in hybrid composite can be defined as proportion of its volume to total reinforcement volume of the composite. The hybrid ratio is an important factor which controls the participation extent of each reinforcement phases in overall properties of hybrid composites. Hence, in the present work, surface hybrid nano composites of Al2024, Graphite average particle size of 100 μm and ZrO2 average particle size of 15 with different. For fabrication of nano composite the tool rotation rate was set to be 1000 rpm, and its advancing speed was 20 mm/min and tilt angle of 3 degree were chosen and all samples were subjected to 2 passes of FSP to obtain more homogeneous dispersion of the reinforcements. Subsequently, effect of hybrid ratio on microstructural, mechanical and tribological properties investigated. Optical microscopy and scanning electron microscopy were utilized to perform microstructural observation on the samples showed that reinforcements are well dispersed inside the Nugget Zone. Hardness value measurements and pin on disk dry sliding wear tests were carried out to investigate effect of hybrid ratio on mechanical and tribological properties of the nano composites.
Kamal Amory, Jamal Amory, Saeed Ahmadifard, Mahdi Kazazi, Shahab Kazemi,
Volume 16, Issue 10 (1-2017)
Abstract
In this study, A356 aluminum alloy matrixcomposites reinforced with different weight percentages of SiC nano- and microparticles respectively with 50 nm and 5 µm average particle sizes were fabricated by stir casting method. Due to the effect of T6 heat treatment on the strength and hardness of A356alloy, the obtained composites were subjected to the T6 heat treatment. The mechanical properties such as hardness and compressive properties of the composites were investigated. Microstructures of the samples were also investigated by an optical microscope (OM), scanning electron microscope (SEM) and field emission scanning electron microscope (FESEM). Microstructural investigation indicated that T6 heat treatment led to thechange of eutectic silicon morphology and formation of theMg2Si precipitates during age hardening stage, leading to increase the hardness and compressive strength. The results showed that an increase in wt.% of nanoparticles led to an increase in hardness and compressive strength. The results of microstructural investigationshowedthe relatively uniform distribution of reinforcement particles. Also, the strength and hardness of the composites reinforced with nanoparticleswere greater than those of the composite reinforced with microparticles, even with higher weight percent of reinforcement particles. Hardness and compressive strength at 35% strain for the composite reinforced with 1.5 wt.% nanoparticles were respectively obtained 62 HBN and 252MPa, which are improved compared to the base alloy.
Saeed Ahmadifard, Amir Momeni,
Volume 17, Issue 8 (10-2017)
Abstract
The purpose of this investigation was the fabrication of surface nano composite composed of aluminum 2024 and boron carbide particles with the average size of 60 nm by the friction stir processing (FSP) method. The primary FSP tests showed that the rotating speed of 850 rpm and traverse speed of 25 mm/min are the optimum conditions which results in sound defect free samples. Then, the effect of nano particles addition and number of passes were analyzed in the fabricated samples. Optical and field emission scanning electron microscopy techniques showed that the average grain size in the stirring zone decreases by adding nanoparticles to the matrix and increasing the number of FSP passes. The hardness and the abrasion tests showed that strength and wear resistance of the fabricated samples increases with increase in number of passes. The improvement in the mechanical properties was attributed to the uniform distribution of the reinforcing particle and grain refinement. However, in the FSPed base metal the hardness was decreased due to the dissolution of primary strengthening particles during the FSP process. The result of electrochemical tests indicated that corrosion behavior of the FSPed samples improves by adding the reinforcing particles and increasing the pass number.
Hirbod Ahmadifar, Amin Yaghootian,
Volume 17, Issue 9 (11-2017)
Abstract
In this study, an improved third order shear deformation theory is used to analyze the thermoelastic buckling of a functionally graded rectangular plate. The plate is assumed to be under two types of thermal loading, namely, uniform temperature rise across the thickness and linear temperature change across the thickness of the plate. Moreover, the material properties of the functionally graded plate vary linearly through the thickness and simply supported are considered for all edges of the plate. First, the nonlinear strain-displacement relations are considered based on improved third order theory and then the equilibrium and stability equations are derived. In continue, displacements and the pre-buckling forces are calculated using the equilibrium equations. The temperature difference relation of buckling is obtained by solving the stability equations. To obtain the critical temperature difference, the recent relation is minimized with respect to the number of half wave parameters. Resulting equations are compared with the literature. The results show that, the values of temperature difference buckling obtained based on improved third order shear deformation theory, are lower compared with the classical plate theory, first and third order shear deformation theories. Moreover, the value of critical temperature difference under linear temperature change is bigger compared with the uniform temperature rise across the thickness, and the difference between the two values will be bigger with increasing the thickness of the plate.
Saeed Ahmadifard, Akbar Heidarpour, Shahab Kazemi,
Volume 18, Issue 3 (5-2018)
Abstract
In this study friction stir welding was used to perform butt joint of Al5083 and simultaneous production of Al-ZrO2 nanocomposite in weldment. Welding parameters such as rotational speed, travel speed and tilt angle were varied to obtain optimum weldment with no defect and high tensile strength, and then by adding zirconia nanoparticle to welding zone of optimum sample, the effects of pass number on microstructure, mechanical properties and wear characteristics of welded specimens were investigated. In order to investigate microstructure, optical and scanning electron microscope and atomic force microscope was used. Results showed that by increasing pass number, the distribution of nanoparticles in the matrix become more homogenous and grain size in the stir zone has considerably decreased. The reason of this phenomena could be attributed to the presence of reinforcement nanoparticles which it causes pinning the grain boundary, enhancing nucleation of new recrystallized grains and the effect on breaking of initial grains. The maximum microhardness and tensile strength of weldment were obtained for composite weldment after four pass of 111 Hv and 328.3 MPa, which these values were 24 and 26% higher than weldment without reinforcement. Wear resistance of the weldment was determined by pin on disk test and revealed that by increasing pass number of FSW, the wear resistance increased.
Volume 25, Issue 2 (2-2023)
Abstract
The rich diversity of Persian carpets is a symbol of different cultures and traditions in this country. To ensure sustainability of the Handmade Carpet Industry Knowledge and Innovation System (HCIKIS), attention should be paid to the transformative approach that pursues holistic transformation in the production and consumption systems. The present study aimed to identify Formal Transformation Institutions (FTIs), classify them into main categories, and analyze them based on the production step, approval date, institution type, and geographical area of approval. Based on the results, there were 316 Formal Institutions (FIs) in the Handmade Carpet Industry (HCI). By open coding, 372 concepts were extracted from 509 concepts derived from different FTIs. Based on the axial coding, the FIs were divided into six initial categories of “carpet authority”, “carpet sales and maintenance inside Iran”, “handmade carpet exports and imports”, “carpet production infrastructure”, “handmade carpet production”, and “sanitary-therapeutic category”. At the next step, the matrix of the main categories based on different production steps was drawn. Among the main categories, the highest frequency was related to the category of “carpet production infrastructure” and the subcategory of “financial supply of carpet”. Although there are many FIs that support production, carpet weavers, as the main people involved in production, have received minimum supports during their working years due to unawareness of supports and loan conditions.
