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Showing 18 results for Ajam


Volume 0, Issue 0 (ARTICLES IN PRESS 2024)
Abstract

Various factors, such as temperature stress, dietary changes, and the entry of contaminants and infections into the hemolymph, are known to affect insect immune responses by altering hemocyte profiles. The research focused on the hemocyte profile, hemogram across all biological stages, and the morphological and frequency changes of hemocytes in third instar larvae exposed to temperature stress. Cucumber fruits infected with insect larvae were collected and brought to the laboratory, where third instar larvae were extracted from the fruit tissue. The hemolymph was then collected, and after staining with Giemsa solution, hemocytes were identified under a light microscope. The hemogram analysis included measurements of DHC, THC, blood volume, and AHC across all biological stages. In third instar larvae, plasmatocytes and granulocytes were the most abundant, comprising about 56% of the hemocyte population. In contrast, prohemocytes were most frequent in the first instar larvae, accounting for approximately 37%. THC was highest in third instar larvae, indicating a direct correlation between hemolymph volume and total hemocyte count. Temperature stress had a significant impact on hemocyte numbers. Heat stress, with temperatures up to 30 and 35 °C, led to a notable increase in total cell count, granulocytes, and plasmatocytes. Conversely, cold temperatures resulted in a decrease in prohemocytes, plasmatocytes, granulocytes, and the total cell count compared to the control group. Additionally, temperature stress induced hemocyte deformation, with plasmatocytes and granulocytes showing the most pronounced changes under heat stress, including torn cell walls and loss of cell contents at 35 C.

Volume 0, Issue 0 (Articles accepted at the time of publication 2023)
Abstract

Children's poetry is a suitable and effective platform for moral and social development and increasing their mental and cognitive abilities. In this respect and due to the importance of the content of children's literary works in the education system, it is necessary to understand children's poetry from different angles. People's culture is a wide collection of elements related to the material and spiritual life of the people of a land, which preservation and transmission to the children's audience and strengthening its place in the thoughts of composers of this field is the reason for the influence and creative productivity of this rich culture. Among them, material traditions are people's daily issues such as tools, food, clothing and vehicles. The present essay examines the reflection of these material traditions in Shaaban Nejad's epic poems. review method; Analytical-descriptive based on library sources. The results show; Shaaban Nejad's poetry as a main source in research; It has a clear and conscious link with people's culture. By using the material examples of people's culture, he connects the past and the present together, with the help of narration, rhythm and song, wide range of vocabulary, imagery and literary works, he displays his ancient roots for the child of the modern world and flourishes and The stability of children's and adolescent literature in Persian language.

Volume 3, Issue 2 (9-2013)
Abstract

  Managerial researches emphasize an organizational contingency elements rule at improving the performance. Although, few theorical and empirical researches were implemented upon the influencing elements at organizational performance. This paper is an effort to fill gaps of corresponding issue. For this, exploration and searching the literature and expert interviews (DELPHI) resulted in formulation of 14 contingent elements which impact the military organization performance. Then, an importance- performance analysis technique based on experts needs and expectations was used to prioritize the elements performance. This technique also presents weakness and strength of influencing performance elements. In this paper, to improve the validity and practical aspects of importance- performance analysis technique, experts and personnel of mentioned organization were interviewed. Then, two quantitative and qualitative techniques multiple regression and DEMATEL final values as integration of implicit and explicit importance respectively are used to extract the importance rates. Finally, the performance rate extracted through interviews based on likert values as well as importance rate applied to build the importance- performance matrix in four quadrants which based on two axes (importance, performance) to analysis the feature of located elements in each quadrant.    

Volume 12, Issue 1 (4-2012)
Abstract

In this paper, an optimal adaptive fuzzy integral sliding mode control is presented to control the robot manipulator position tracking in the presence of uncertainties and permanent magnet DC motor. In the proposed control, sliding surface of the sliding mode control is defined according to the information of position tracking error, derivatives, and error integral. In order to estimate bounds of the existing structured and unstructured uncertainties in the dynamics of the robot manipulator and the permanent magnet DC motor, a MIMO fuzzy adaptive approximator is designed. This helps to overcome the undesired chattering phenomenon in the control input by using fuzzy logic. Mathematical proof shows that the closed-loop system with the adaptive fuzzy integral sliding mode control in the presence of all the uncertainties has the global asymptotic stability. Furthermore, modified harmony search optimization algorithm is used to define the input coefficients of the proposed control and also to reduce the control input amplitude. In order to validate performance of the proposed controller, a case study on the SCARA robot manipulator is conducted in the presence of permanent magnet DC motor. Results of the Simulation show desired performance of the proposed controller.

Volume 13, Issue 2 (11-2024)
Abstract

 The accumulation heavy metals in the soil poses a significant risk to the health of plants, animals, and human communities. This study investigated the effect of small amounts of iron, zinc, and copper salts on hemocyte abundance, nutritional indices, and biological characteristics of the Ephestia kuehniella Zeller in-vitro. Fourth instar larvae were treated with iron, zinc, and copper salts at 25, 50, and 100 mg/kg in 24 and 48 h intervals. Immunological assessments included total hemocyte count, plasmatocytes, granulocytes, and phenol oxidase enzyme activity. The results demonstrated significant changes in immunological parameters compared to the control group. Notably, iron and zinc at 100 mg/kg exhibited the significant increase in enzyme activity at both 24 and 48 h. Conversely, iron caused a significant decrease in the activity of this enzyme after 24 h at 50 mg/kg when compared to other treatments. In terms of nutritional indicators, copper metal salt at 25 mg/kg enhanced the relative growth rate compared to the control. This preliminary study highlights the significant impact of zinc, copper, and iron salts on the biological characteristics and immune response of E. kuehniella. These findings suggest that the incorporation of small amounts of these metals into the insect's diet can induce biological and physiological disorders.


 

Volume 13, Issue 54 (8-2015)
Abstract

  The aim of this study was to investigate the effect of frying temperature and replacement of soybean protein isolate (SPI) with wheat flour on chemical characteristics doughnuts. For this purpose samples doughnuts formulated replacement 3 and 7 percent SPI with wheat flour null and then fried at temperatures 150, 165 and 180 °C. Parameters moisture content, fat content, acid value, peroxide value and sensory properties were investigated. Statistical analysis was performed using a completely randomized factorial design. Means were compared using Duncan's test (p≤0.05) with each other. The results shown that, with increasing temperature and percentage replacement of wheat flour with SPI led to increasing moisture content and the oil content decreased in samples were doughnuts. Temperature increases from 150 ° C to 180 ° C in the process frying doughnuts Samples prepared with wheat flour, 3% and 7% SPI led to Increasing acid value oil absorbed in their 0.66, 0.64, 0.51 unit, respectively. Results of variance analysis showed significant effect type flour on the amount of hydroperoxides on oil is absorbed on case of donuts (p≤0.05). The results of the comparison means showed not follow the effect of the specific. The raters doughnuts Samples no significant difference in terms of our sensory evaluation (p≤0.05).
Farshad Meisami, Hossein Ajam,
Volume 15, Issue 4 (6-2015)
Abstract

Biodiesel is a renewable fuel that can be produced from vegetable or animal oil. The main benefit of using biodiesel is its capacity to lower exhaust emissions compared to diesel fuel. Over the last few years, numerous studies have been performed on biodiesel production and its effect to engine performance and emissions. However, in those studies; no attention has been paid in economic analysis of biodiesel usage in engines. In this investigation, various mixtures of biodiesel and diesel fuel have been tested on a four cylinders turbocharged diesel engine. The combustion reaction was determined by using the experimental data. Then, the mass flow rate of each exhaust emissions was calculated, using combustion reaction. The economic analysis was performed considering social cost of emissions, inlet fuel cost and the cost of engine power loss. Because of low diesel fuel price in Iran, the results were determined by ignoring the inlet fuel cost. The technical analysis was also performed considering the engine performance results. The results showed that the 10% and 15% biodiesel-diesel blends (B10 and B15) were more affordable than diesel fuel. The performance results of engine were also acceptable in these blends. The power loss was slight and the highest thermal efficiency was also observed in these blends. All biodiesel blends were more affordable than diesel in emissions economic analysis
Hamideh Sheikhani, Mohsen Ghazikhani, Hosein Ajam,
Volume 15, Issue 4 (6-2015)
Abstract

Nozzles branching, fuel injection angle and nozzle diameter can affect the mixing process and combustion performance of nozzle-mix burners. In the current work, CFD approach and Taguchi method are employed to investigate the effects of these parameters on the irreversibility of combustion process. Combustion in nozzle-mix burner is first simulated by use of CFD method. The governing equations, including continuity, momentum, energy and chemical reactions are solved numerically by use of FLUENT. Standard k-ε and EDC models are used for modeling turbulence and interaction between chemical reactions and turbulence, respectively. Then, the developed model is experimentally investigated and numerical method is validated. Using the Taguchi method, the effects of each parameters, their priority and optimum values are determined by use of Minitab. A L9(33) orthogonal Taguchi array is used with the analysis aim of minimizing irreversibility. Results show that injection angle, number of branches and nozzle diameter have the most influence on the combustion irreversibility, respectively. The optimum configuration of the nozzle-mix burner is determined to have a 45º injection angle, 4 branches and 4mm nozzle diameter. The corresponding irreversibly to this optimum case is 45.88%.
Mostafa Dehghani, Hossein Ajam, Saeed Farahat,
Volume 15, Issue 7 (9-2015)
Abstract

In order to assess the effect of turbulence models in prediction of flow structure with adverse pressure gradient, steady state Reynolds-averaged Navier-Stokes (RANS) equations in an annular axisymmetric diffuser are solved. After selection of the best turbulence model, an approach for the shape optimization of annular diffusers is presented. The goal in our optimization process is to maximize diffuser performance and, in this way, pressure recovery by optimizing the geometry. Our methodology is the optimization through wall contouring of a given two-dimensional diffuser length and area ratio. The developed algorithm uses the CFD software: Fluent for the hydrodynamic analysis and employs surrogate modeling and an expected improvement approach to optimization. The non-uniform rational basic splines (NURBS) are used to represent the shape of diffuser wall with two to ten design variables, respectively. In order to manage solution time, the Kriging surrogate model is employed to predict exact answers. The CFD software and the Kriging model have been combined for a fully automated operation using some special control commands on the Matlab platform. In order to seek a balance between local and global search, an adaptive sample criterion is employed. The optimal design exhibits a reasonable performance improvement compared with the reference design.
Mostafa Dehghani, Hossein Ajam, Said Farahat,
Volume 16, Issue 2 (4-2016)
Abstract

The purpose of this paper is to find the optimum design of a typical gas turbine exhaust diffuser. In order to access the maximum overall static pressure recovery at the condition of swirling flow, an evolutionary algorithm is used. The optimization process is studied in three independent cases. Firstly, the optimization is done for a single profile of strut cover from hub to shroud. Secondly, two profiles are selected for the strut covers, one in the hub section and the other in the shroud section. Finally, the optimization process is done for the strut cover and diffuser channel geometries simultaneously. In order to produce the strut cover profiles the PARSEC parameterization method is used. The turbulent 3D flow is solved using computational fluid dynamic (CFD). The optimization process starts with the initial sampling of solution domain and subsequently the genetic algorithm (GA) is used to find the global optimum. The swirling flow at the turbine exit with the Reynolds number of 1.7 ×105 based on the hydraulic diameter of the diffuser inlet is optimized. All steps of GA and corresponding processes of model creation, mesh generation by TurboGrid, flow simulation by ANSYS CFX and goal function calculation for all members of each generation are coded in the MATLAB platform. As a result of the optimization, the pressure recovery coefficients increased 1.94%, 3.1% and 7.42% in the first, second and third cases of the optimization process respectively.

Volume 16, Issue 4 (winter 2016 2016)
Abstract

The government of Iran has faced with budget deficits during 1979 – 2010, which has been financed mainly through money creation. Theoretically, the impacts of budget deficit and inflationary tax on macroeconomy are very controversial, so that both decrease and increase in consumption, investment, net exports and total expenditure have been supported by empirical researches. Using structural cointegrating vector autoregressive, this paper investigates the impacts of inflationary finance on the demand side of Iran’s economy during mentioned period. Budget deficit is defined as the difference between operating budget deficit (minus net operating balance) and capital balance surplus, or net lending (net acquisition of nonfinancial assets). The results show that both operating budget deficit and net lending have positive impacts on consumption, investment and net imports in the short run. So changes in the demand side have not necessarily same orientation with increase or decrease in budget deficits, but the source of change in budget deficit determines its effects. Reducing budget deficits through positive shock to net lending and a policy of increasing operating budget deficit have similar effects. Furthermore, the results show that the operating budget deficit has no effect on demand components in the long run. The complementarity of inflationary tax and financial repression is confirmed in both short run and long run. In addition, the results indicate that an increase in operating budget deficit and/or net lending induce more inflationary tax and financial repression. Although the budget deficit has no effect on demand side in the long run, but its two outcomes -inflationary tax and financial repression- have opposite effects on the consumption, investment and net imports in both short run and long run.
 

Volume 16, Issue 91 (September 2019)
Abstract

In present study, the effect of the percentage of meat in the first stage (three levels of 30, 60% and 90%) and replacement of dried milk powder with soybean meal in the second stage on amount of acrylamide formed in grilled beef and chicken burgers (containing 60% meat) was investigated. Also, total sugar, protein, moisture and sensory characteristics of burgers were determined. The results indicated that the amount of acrylamide in chicken burgers was significantly less than that of beef burgers (p <0.05). The highest and the lowest amounts of formed acrylamide related to meat burger 60% (66.03 μg/kg) and chicken burger 90% (26.54 μg/kg), respectively. Further, the increase of the beef and chicken meat content from 30 to 60% led to increase in acrylamide while increasing from 60 to 90% resulted in decrease in the amount of formed acrylamide. The total sugar content of chicken meat burgers was significantly higher than that of beef burgers while their protein content was lower (p<0.05). The results also indicated that increasing replacement of dry milk powder caused to increase in amount of formed acrylamide in the burgers. The highest and the lowest amounts of acrylamide in the second stage related to the beef burger contains 16% dried milk powder (69.25 µg/kg) and chicken burger containing 8% dried milk powder (40.35 µg/kg). It seems the lowest amount of acrylamide in burgers would be formed in present of the chicken burgers containing 90 percent meat without dried milk powder

Volume 17, Issue 3 (5-2015)
Abstract

SCID is a lethal genetic autosomal recessive disorder that has been observed in humans, dogs, mice, and horses. Affected animals are incapable of generating specific antigens for immune responses needed to protect them from infectious diseases. The frequency of affected recessive allele varies in different regions so that the outcome of normal breeding with carriers of recessive alleles is differently distributed. Little information is available for SCID carriers in Iranian horses to prevent carriers breeding. In this study, the occurrence of the SCID alleles was tested in representative samples of Persian Arabian (or Asil) horses. Blood samples were collected from 244 Arabian horses in eight provinces of Iran. The ARMS-PCRs were used for the first time to identify SCID carriers, based on three distinguishing primer pairs. Each sample was used in two separate PCRs with a common forward primer. The two reverse primers differed in their 3′ end: one reverse primer could pick the wild-type allele while the other could pick the mutant allele with a 3′ end deletion. An internal control (HMS02 locus) was used in both reactions to verify whether the amplifications worked correctly. The results showed a mutated allele frequency of 0.8% in the Arabian horse population of Iran. This is the first report identifying SCID carriers’ frequency among Arabian horse population in Iran.

Volume 19, Issue 3 (9-2015)
Abstract

Capital structure policy is a mean to tradeoff between risk and return and many factors influencing the optimal capital structure for each company. The aim of this study is to investigate the factors affecting the capital structure of companies listed in Tehran Stock Exchange and some selected stock exchanges in the developed and developing countries, and compare these determinants in a domestic versus international setting. Determinants of capital structure, considered in this research, are in the firm and country levels. In the firm level, profitability distance from bankruptcy, size and the ratio of fixed assets to total assets are used, and in the country level, the role of country’s GDP growth and stock market development is investigated. For international companies, we used Compustat Global Vantage database and World Bank databases and for domestic companies, we used Tadbirpardaz database to collect data. The findings showed the determinants significantly effecting on capital structure in four populations: the whole world, developed countries, developing countries, and Iran. Finally, we found that the developed and developing countries profitability and the size have different effects on capital structure. Alternatively in comparison between Iran and the developed countries, size and the ration of fixed assets have different effects on capital structure.
M.r. Moharreri, H. Ajam,
Volume 19, Issue 3 (March 2019)
Abstract

Ejectors are as widely used as in food industries to refrigeration cycles and power plants. Since condensers of steam power plants are operated in vacuum conditions, there is a continuous air leakage, which results in metal corrosion and reduction in efficiency. Therefore, ejectors are used in these systems to remove the air. Over time, leakage increases, which requires more efficiency of ejector. Entrainment ratio (ER) is defined as the main criterion for ejector efficiency and leads to better performance if increased and also depends considerably on geometry of ejector. The aim of this research is to increase efficiency of ejector of Touss Power Plant by simultaneously changing nozzle exit position (NXP) and converging angle of mixing chamber. The main geometry of ejector was simulated by FLUENT and primary results were validated with experimental and computational data. Then, different geometries with simultaneous change in NXP and converging angle of mixing chamber were selected in the first step of Taguchi method and simulated by FLUENT. Geometries of the second step of Taguchi method were selected and designed based on the results of signal-to-noise ratio for the above-mentioned parameters and the values of entrainment ratio in the first step. An identical approach was followed for the third step. Final results showed 34% increase in entrainment ratio and also revealed that there is an optimum value for NXP and converging angle of the mixing chamber around which the value of entrainment ratio is maximum.
 



Volume 21, Issue 3 (Autumn 2021 2021)
Abstract

Dependency of Iranian Economy on oil revenues has provided conditions for imposing further sanctions on Iran. One way for Iran to get rid of sanctions is to sell its oil in currencies other than US dollar. In this regard, this article evaluates the risks for Iran if it, in selling oil, substitutes US dollar with currencies of its oil importing countries. We firstly apply Autoregressive Integrated Moving Average (ARIMA) and Self-Exciting Threshold Autoregressive (SETAR) models on Yuan and Rupee data for the period of 1990:01-2019:05 as well as on Euro data for the period of 1999:01-2019:05 and then based on the estimated models, forecast losses and gains for the period of 2019:06-2021:12 if Iran sells oil to China, India and Europe and receive payments respectively in Yuan, Rupee and Euro. Our forecasts indicate that selling oil to India and China and receiving oil revenue in Rupee and Yuan respectively will significantly decrease value of oil exports in range of 5-23 percent due to very likely devaluation of these currencies vs. the US dollar. Therefore, Iran must firstly use in its oil transaction relevant diplomacy with its oil importing countries, requesting them to share in risks of devaluation of their currencies vs. US dollar. Secondly, as a particular example, this article shows that political decisions may bring in economic consequences for the country. Therefore, Iranian authorities are expected to consider economic consequences of their political decisions more seriously and with sufficient transparency.
Mohsen Mohammadi_sarasia, Hossein Ajam, Ahmad Moloodi,
Volume 21, Issue 7 (July 2021)
Abstract

In the present study, the effect of the porous medium in natural-gas pressure regulators, on the operation and reduce the intensity of the sound produced, is studied. First, it was studied experimentally. Experiments apply for the porous medium 20 ppi (pores per inch) and 10 ppi and non-porous system. To check the validity of the results, experiments were evaluated in four different pressure upstream 20, 10, 5, and 2.5 MPa on the critical pressure ratio. Afterward, for evaluation of the flow parameters on the performance of regulators and the sound intensity level, numerical simulation of fluid flow was performed. The results show that the use of porous media for 10 ppi and 20 ppi, flow coefficient decrease, respectively 7% and 15%, and sound intensity level decrease, respectively 25 and 30 dB. The amount of porosity does not have much effect on the sound intensity. On the other hand, the results of the fluid flow simulation show that placing the porous medium in the flow direction reducing the turbulent intensity and regulating the flow. As well, it decreases the sound intensity by decreasing the maximum velocity and the vortex power.
Masoud Sobhani, Hossein Ajam,
Volume 24, Issue 3 (March 2024)
Abstract

The limitations of water supply in different countries have led researchers to propose the use of solar still as one of the solutions to the problem of water limitations. In this research, single-slope solar still have been used. Among the innovations of this research, it can be mentioned the improvement of the construction and maintenance of the solar still box by using PVC materials with a sliding absorber plate, as well as the use of wave makers to improve the performance of solar still. the wavemaker by creating surface and deep turbulences and increasing heat transfer, in addition to improving the performance of the solar stills, also prevents the accumulation of materials that are caused by stagnant water and reduce the heat transfer coefficient from the absorber plate. The results of the use of the wave maker showed that with the increase in the number of wave makers, the daily production and efficiency of the improved solar still also increased and reached 4324 ml/m2 per day and 42.6% respectively, which is about 40.2% and 9.7% more than conventional one. The results of the economic study of the improved solar stills also showed that the cost of producing of each liter of fresh water in improved still equipped with wave makers was 0.013 $, which was about 13% less than conventional one.


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