Showing 10 results for Salavati
Volume 7, Issue 4 (Fall 2018)
Abstract
This study was carried out to evaluate the effects of dietary protein levels on growth performance and body composition of Caspian Roach (Rutilus caspicus) fingerling. Four experimental diets were formulated to contain protein levels of 30, 35, 40, and 45%. Triplicate groups of 300 Roach (Average weight, 2.65±0.17g) were stocked in 100L-fiberglass tanks (25 fish/tank) and were fed based on 3% of their biomass for 57 days. The results showed that weight gain (WG%), specific growth rate (SGR), food conversion ratio (FCR), condition factor (CF) and survival (SR%) were not affected by dietary protein level but the protein efficiency ratio of protein levels containing 30 and 35% CP was significantly higher than other dietary treatments (p<0.05).The body compositions were affected by dietary protein levels. Body protein significantly decreased with increasing dietary protein levels but body lipid increased when protein increased to 40% level. The results of the present study indicated that growth enhancement of fish was not significant when the diets protein levels were increased from 30 to 45%, but fish fed a diet containing 30% CP had greater protein efficiency values when compared to those fed with other diets.
Volume 8, Issue 3 (Autumn 2018)
Abstract
This study has scrutinized the methods of optimizing the energy consumption in Isfahan dwelling, and how to provide the residents with comfort, well-being and satisfaction through green architecture. Given the excessive consumption of energy in Iran and also Hot and Arid climate of Isfahan, this essay has aimed at preservation of energy resources for future generations and boosting the quality of life for the dwellers by means of green architecture. This article, by revealing the notion of comfort, has confirmed that the ecological architecture would minimize the required energy through maximum use of natural desired conditions alongside protecting buildings from unfavorable climatic factors and would provide a part of energy within the natural way. As a result, comfort would be offered in the areas, in a more pleasant way. With the green architecture approach, studies on the historical houses in Isfahan indicate the desirability of life quality in these buildings through improving comfort by means of optimizing energy use. Nowadays, the urgency of developing sustainable behavior, including the management of energy resources, is evident. Considering the prominence of the users’ behaviors in achieving sustainable architecture goals, this paper, by putting basis to Maslow pyramid, has suggested two strategies, “training” and “resource management”, so as to promote sustainable behaviors. This research has been based on applied research methods, citing library studies and electronic resources. In the end, it has argued about how to select eco-friendly materials and has proposed utilizing recycled materials and reusing of waste in favor of green design.
Volume 15, Issue 2 (4-2015)
Abstract
In the present study, in order to evaluate the elastic displacement field and subsequently the fracture parameters within the isotropic homogeneous elastic solids with the edge or interior cracks, the extended finite element method with level set technique was used to avoid the disadvantages associated with the standard finite element method. An overdeterministic least squares method was utilized to determine the crack stress intensity factors as well as the coefficients of the higher order terms in the Williams' asymptotic series solution for structures containing crack in various modes of failure by fitting the series solution of displacement fields around the crack tip to a large number of nodal displacements obtained from the extended finite element method. For validating the results, several cracked specimens subjected to pure mode I, pure mode II, and mixed modes I/II loading were performed. Comparisons with results available from the literature obtained by the other formulations reveal the efficiency and the simplicity of the proposed method and demonstrate the capability of it to capture accurately the crack stress intensity factors and the coefficients of higher order terms.
Volume 16, Issue 2 (4-2016)
Abstract
According to the importance of the engine emission and because of the cost of the laboratory tests, it is necessary to simulate the engine via numerical methods. In this study a numerical simulation of single cylinder SI engine has been carried out to predict the internal combustion engine emission with the AVL BOOST software. The engine calibration has been performed in 2000 rpm engine speed and three loads (part load, mean load and WOT) and three compression ratios (12, 14, 16) with stoichiometric air fuel ratio. After the calibration of engine, the Lambda value is changed in range of 0.8 to 1.25 and the NOx and CO values are calculated. the results show that emission of NOx is dependent extermly to load of combustion engine but compression ratio has not very influence on this emission.unlike the NOx, the both compression ratio and load don't have any effects on CO values.
Volume 16, Issue 4 (6-2016)
Abstract
Tissue engineering is a rapidly growing field of research for several decades, which is driven by the human urgent need for tissue substitutes and transplantable organs. Considering the advancements, the clinical applications in the field of tissue engineering have been limited until now. The major reason toward this limitation is the lack of sufficient blood supply for the tissue in the earliest phase after implantation. Time-consuming process of angiogenesis leads to inadequate vascularization and finally, death of cells and destruction of tissue. During recent years, by implementing a strategy called Inosculation, it has been tried to facilitate tissue vascularization by a preformed vasculature network within tissue structure. In the current research considering cellular nature of angiogenesis process, relying on a cell-based mathematical model, the effect of inosculation strategy is investigated through the dynamics of angiogenesis process with respect to extracellular, cellular and intracellular spatio-temporal scales. The results show the advantages of inosculation strategy over angiogenesis strategy in vascularization of tissue constructs. The model demonstrates the capability of inosculation strategy to improve the anastomosis probability, which is providing the crucial requisite for the blood to flow through capillary network. Furthermore, the cellular model was developed in a way that illustrates the effects of extracellular matrix on morphogenesis through branching phenomenon.
Volume 16, Issue 11 (1-2017)
Abstract
In the present study, AM60 magnesium alloy was casting and then subjected to hot extrusion process. Next, Multi Directional Forging (MDF) experiments with six pass numbers were conducted to investigate the influence of the operation on the microstructure and mechanical properties of these alloys. The shear punch test (SPT) and Vickers microhardness test were employed to evaluate the mechanical properties of the extruded and MDFed samples. Both the shear yield stress (SYS) and ultimate shear strength (USS) obtained from the shear punch test increased just after two passes but decreased with further pressing, although it was expected that the grains became finer with increasing the pass number. After two passes USS increased from 121.58 MPa to 142.42 MPa. This rise and fall indicates that texture softening overcame the strengthening effects of the grain refinement. The Vickers microhardness was measured across the cross sections of the extruded and MDFed samples, the results of this test also confirms that rise and fall procedure. The average microhardness of the extruded and MDFed samples were found to be respectively 73.50, 85.93, 82.26 and 77.83 HV for the extruded and 2,4 and 6 passes of MDFed, which confirms SPT results. Optical micrographs showed that processing by MDF reduces the grain size from 11.22 to 1.91 µm after 6 passes.
Volume 17, Issue 2 (3-2017)
Abstract
In this paper, fracture behavior of functionally graded material weakened by U-notches under mode I loading has been investigated. Electro slag remelting process has been used to produce functionally graded specimens in a notch arrester configuration. Hardness test has been utilized to define the position of each layer. Mechanical properties, including elastic modulus and poisson's ratio, vary along the width of U-notched specimens. The critical fracture load (Fcr) was achieved by performing three point bending examination and using force-displacement curve.
Then, the process simulation was done by finite element software. Firstly, Jcr of each specimen was calculated by using critical value of strain energy averaged over a well-defined control volume. Then the critical fracture load was evaluated by means of the J Integral criterion. In this research, the effect of the notch root radius, for a fixed notch depth, on the Jcr value as well as the critical fracture load has been studied. To compare fracture behavior of the FG specimens with the corresponding homogeneous ones, have the same properties with the notch root layer in FG specimen, Fcr and Jcr value of each have been investigated. The average difference between the predicted Fcr by J integral criteria and experimental results is 17.84%. Finally, the effect of number of graded area layers on Jcr and Fcr has been investigated. The results shows, the value of Jcr and Fcr do not be affected while the number the number of layers more than 20.
Volume 18, Issue 3 (10-2015)
Abstract
Objective: Apical membrane antigen-1 (AMA-1) is one of the most promising blood-stage candidate antigens for production of a malaria vaccine against the Plasmodium parasite. Genetic diversity in protective antigens, which is a common phenomenon in a complex pathogen such as the Plasmodium parasite, is responsible for problems with the development of an effective malaria vaccine. This phenomenon will increase the parasite’s ability to evade immune responses. Therefore, malaria vaccine development requires the evaluation of immune responses to different allelic forms of the vaccine candidate antigens.
Methods: In this investigation, the two variant forms of PvAMA-1 (PvAMA-1A and B) were expressed in an Escherichia coli M15-pQE30 system using genomic DNA from Iranian individuals with patent Plasmodium vivax infection. The IgG responses of two antigens were evaluated in BALB/c mice with the purified protein emulsified in Freund's adjuvant. In addition, the correct conformation of the recombinant proteins was evaluated by the indirect immunofluorescence antibody test (IFA).
Results: The evaluation of immunogenic responses of two variant forms of PvAMA-1 showed the presence of IgG responses in mice after three immunizations. Cross-reactions were observed. Monitoring of IgG responses showed the persistence up to one year after the last immunization. The antibodies raised against recombinant PvAMA-1s in injected mice recognized the native protein (PvAMA-1) localized on Plasmodium vivax merozoites.
Conclusion: The present outcomes confirmed the presence of common epitopes in recombinant forms of the protein that corresponded to native proteins. These emulsified proteins in Freund's adjuvant were immunogenic in BALB/c mice and IgG responses persisted for up to one year. The IgG responses to two PvAMA-1 variants did not differ significantly. The presence of cross-reactive antibodies has implied that one of these two forms of protein could be used in a universal blood-stage vaccine based on the PvAMA-1 antigen.
Volume 19, Issue 10 (October 2019)
Abstract
The Nd: YAG pulsed laser welding process with different speed and shielding gas was applied on 2205 duplex stainless steel. The effects of different parameters on the microstructural evolutions and mechanical properties were investigated. Four different zones with different secondary austenite contents were observed in the weld microstructure. By changing the shielding gas from argon to nitrogen, the secondary austenite percentage was not significantly varied. The secondary austenite fraction was showed about 38% reduction with increasing the welding speed. The weld penetration depth decreased with changing the shielding gas from argon to nitrogen (about 26% and 14% reduction at speed of 3.8 and 8.3 mm/s, respectively) and increasing the welding speed (about 43% and 34% reduction under shielding gas of argon and nitrogen, respectively). The variations in microhardness values along the weld line were correlated to the microstructural characterizations. Changing the welding speed had no significant effect on the microhardness variations, but changing the shielding gas from argon to nitrogen caused a significant increase of microhardness.
S. Salavati, H. Ghobari, A. Sadeghi, A. Bayram, M. Maroufpoor,
Volume 24, Issue 6 (11-2022)
Abstract
Potato Tuber Moth (PTM), Phthorimaea operculella (Zeller), is one of the most destructive pests of potatoes under field and storage conditions. Exploiting plant resistance may help control the pest in an eco-friendly manner. Therefore, the present study aimed to assess the resistance status of six common potato cultivars (Banba, Bellini, Draga, Marfona, Jelly, and Milva) under laboratory conditions (25±1°C, 65±5% RH and 14:10 (L: D) hours photoperiod). Life history and demographic parameters of P. operculella under laboratory conditions were analyzed based on the age-stage, two-sex life table theory, which could be appropriate indices in resistance and susceptibility evaluation of potato cultivars. Pre-adult development was slower on Marfona and faster on Banba (19.91 and 21.93 days, respectively) compared to the other cultivars. The longest oviposition days was found on Jelly (8.20 days), while the shortest (5.43 days) was on Bellini. The maximum values of r and λ were found on Marfona (r= 0.160 d-1, λ= 1.173 d-1), whereas the minimum values were recorded on Draga (r= 0.092 d-1, λ= 1.096 d-1). According to the findings of the present study, Draga was considered resistant and a less favorable host plant for the development and reproduction of PTM. These demographic data may be used to better understand the population dynamics of the pest on the six potato cultivars tested, thereby inevitably improve efficient pest management approaches for PTM in both organic and conventional production systems.
