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Showing 22 results for Rafe


Volume 1, Issue 2 (7-2014)
Abstract

Background: Henoch-Schönlein purpura (HSP) is an lgA mediated small vessel systemic vasculitis disease in children. The etiology and pathogenesis of HSP disease remain unknown. However, environmental and genetic risk factors could play important roles in susceptibility to HSP disease. In this study we investigated the association of 5՛-untranslated region polymorphism (-634G/C) of VEGF gene with HSP among Iranian Azeri Turkish population. Methods: Thirty unrelated Iranian Azeri Turkish children with HSP and fifty healthy unrelated subjects without HSP and other inflammatory diseases were enrolled in this population. -634G/C polymorphism of VEGF gene was genotyped by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) technique. Results: The distribution of CC genotype in VEGF -634G/C polymorphism statistically showed a significant difference in HSP patients in compare to that of control group (P= 0.009). Conclusions: The CC genotype of VEGF -634G/C polymorphism could be associated with susceptibility to HSP disease in Iranian Azeri Turkish ethnic group.

Volume 8, Issue 2 (6-2022)
Abstract

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Stenomesius japonicus (Ashmead, 1904) (Hymenoptera: Eulophidae) was collected for the first time from larvae of the tomato leaf-miner, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) infesting Lycopersicon esculentum Mill. in Syria. Diagnostic morphological characters, biology and distribution of the newly recorded species are provided. Its role in the biological or integrated control of T. absoluta remains to be evaluated. A list of all eulophid wasps recorded from Syria is also provided.


Volume 13, Issue 0 (kongore 94- 2015)
Abstract



Volume 13, Issue 0 (kongore 94- 2015)
Abstract



Volume 13, Issue 4 (Number 4 - 2011)
Abstract

To increase agricultural crops’ quality and to minimize losses in the final product and used energy during the drying process, major drying system parameters should be continuously controlled. Precise control of such parameters is attained by using automatic control systems. To optimize the overall dryer efficiency in a forced convective solar dryer, a controller was designed, constructed and evaluated. The dryer fan speed was chosen to be the controlled variable. Based upon the mathematical relations and a monitoring of the air inlet temperature to the collector, the air outlet temperature from the collector and the air outlet temperature from the drying chamber, the dryer efficiency was determined. Using the dryer control program the current and the optimized dryer efficiencies were calculated, compared and the fan speed changed accordingly to maintain the optimized efficiency. Experiments were carried out in three replications (in three days) with the results showing that the system was capable of controlling the fan speed to obtain the optimum efficiency. The dryer equipped with the designed control system worked with its highest efficiency throughout the day. Statistical analysis showed that the control system highly improved the dryer efficiency throughout its operation at a 1% probability level.

Volume 14, Issue 15 (Third Special Issue 2015)
Abstract

This paper presents the investigation of general formulation and numerical solution of the dynamic load carrying capacity (DLCC) of flexible link manipulator. The proposed method is based on open loop optimal control problem. A two point boundary value problem (TPBVP) is provided, extracted from the Pontryagin's minimum principle. The indirect approach is employed to derive optimality conditions. The system’s dynamics equation of motion is obtained from Gibbs-Appell (G-A) formulation and assumed mode method (AMM). Elastic properties of the links are modeled according to the assumption of Timoshenko beam theory (TBT) and its associated mode shapes. As TBT is more accurate compared with the Euler-Bernoulli beam theory, it is exploited for mathematical modeling of flexible links. The main contribution of the paper is to calculate the maximum allowable load of a flexible link robot while an optimal trajectory is provided. Finally, the result of the simulation and experimental platform are compared for a two-link flexible arm to verify the introduced technique. The efficiency of the proposed method is illustrated by performing some simulation studies on the IUST flexible link manipulator. Simulation and experimental results confirm the validity of the claimed capability for controlling point-to-point motion of the proposed method and its application toward DLCC calculation.

Volume 15, Issue 2 (4-2015)
Abstract

The present study aims to implement an approach for trajectory control of a 3-RPR parallel manipulator over a path with obstacles in the workspace. For this purpose, using the spline curves approach and based on the cuckoo optimization algorithm, a smooth reference trajectory with minimum length is generated in the workspace to avoid robot collision with obstacles. The performance and accuracy of the cuckoo optimization algorithm in converging to the optimal solution is then compared with the Genetic algorithm. In the next step, the robust sliding mode control technique is adopted for trajectory control of the robot in the presence of some uncertainties. These uncertainties usually include the links length and links mass of the robot. The obtained results confirm the demanded level of performance and accuracy of the cuckoo optimization algorithm. It is also observed that the optimal trajectory with minimum length is generated using the spline curves approach. In addition, it is concluded that based on the sliding mode control technique, the robot can follow the desired trajectory very precisely in spite of the presence of the uncertainties in length and mass of the robot's links.

Volume 15, Issue 4 (6-2015)
Abstract

In hydroforming process, the curve of internal pressure versus axial feeding is called loading path which is the key to produce a desire product. Finite element simulation of tube hydroforming can be used to study the loading path effect on the final part characteristics. In this research the finite element simulation of pulsating hydroforming process has been done in conjugation with two different work hardening models: an isotropic hardening and a mixed isotropic-nonlinear kinematic hardening model, which is capable to describe the Bauschinger effect. The parameters of both hardening models have been obtained from tensile test data. The result of the both finite element simulations were compared to experimental work. The results show that the mixed hardening model gets better prediction of final product characteristics than isotropic hardening. The differences between the results of two hardening models are from this fact that in a hydroforming process the tensile and compression loads are used and the loads reversal may be occurred. To study the effect of pulsating pressure on tube material characteristic, a three-step bulge test with unloading has been done and the results have been compared to monotonic bulge test. Loading and unloading of internal pressure cause a higher bulge height for a final pressure level compared to monotonic bulge height. The finite element simulation of pulsating hydroforming has been compared to linear hydroforming. The reported bulge heights and thicknesses show an improvement in formability of tubular material in pulsating hydroforming by considering the average pressure level which was applied.

Volume 15, Issue 8 (10-2015)
Abstract

Phenomenon of dispersion and deposition of nano- and micro-particles in turbulent flows been focused in the past decades. In this paper, particle dispersion and deposition in gas-particle two-phase turbulent flow inside a two-dimensional channel with rectangular artificial roughness is studied using an Eulerian–Lagrangian method. The RSM turbulence model with enhanced wall treatment was used to simulate the anisotropic turbulent gas phase flow. The gas phase flow predictions were validated by comparing the results with available experimental data for a fully developed asymmetric turbulent channel flow. In discrete phase, Lagrangian approach was applied for particle tracking. The Lagrangian equation of particle motion includes drag, gravity, Saffman lift, and Brownian forces. The particle phase simulation results were validated by comparing the present work with available equations and valid data for a gas particles turbulent flow inside a two-dimensional smooth channel. The gas phase simulation results show that by increasing the artificial roughness height, a recirculation region which is created in the space between two ribs, becomes larger. The particle phase results show that the rate of deposition in the channel with artificial roughness is a function of gravity force and flow pattern in the space between two ribs. The rate of deposition for small particle is affected significantly by gas flow pattern in the space between two ribs. However for large particles the gravity force is more dominant.

Volume 16, Issue 8 (10-2016)
Abstract

Full feedback data is mostly essential in control design. The measurement of the variation of flexible joint robot (FJR) actuators is not easy as the measurement of the changes of FJR links’ angles. The measurement of the states is also affected by noise, and the disturbance in the workspace of the robot is not ignorable. Hence a state observer or a nonlinear estimator is necessary to improve the performance of the dynamic system. The state-dependent Riccati equation (SDRE) is one of the most promising nonlinear optimal control methods for estimating variables of systems. Systematic procedure, simple structure, and incorporating wide range of systems (under observability condition) are some advantages of SDRE method. The majority of nonlinear techniques linearize the model, but the SDRE directly uses the nonlinear state space; it is one of the reasons for its precision and flexibility in design with respect to other methods. The goal of this work is to merge the SDRE controller and estimator simultaneously to reduce the state error of the system in presence of external disturbance and measurement noise. So, first, the controller and the observer formulation has been stated. Then, the procedure has been applied to design and to simulate a 3 DOF robot arm with flexible joints. Next, the process has been tested experimentally using Scout robot and the simulation results have been verified. Finally, the proposed method of this paper has been compared with the optimal sliding mode.

Volume 16, Issue 11 (1-2017)
Abstract

Nowadays, movement of micro/nano particles has been attracted considerable attention to manufacturing different devices in micro/nano scale and medical and biological applications. Atomic Force Microscope Probe is widely being used for precise small scale movements. During nano-manipulation, micro/nano particles can be moved to a desired destination with high accuracy using Atomic Force Microscope while in contact mode with precise probe control. In this article, by selecting a proper amount of torque applied to the probe tip, deviation from the center and movement of probe have been investigated to assure the contact between the probe and micro/nano particle. Different liquid environments (water, alcohol, and plasma) with different micro/nano particles including biological and non-biological have been used for this investigation. In addition, using sliding mode control, Atomic Force Microscope Probe was used in different environments such as water, alcohol, and plasma. Obtained results showed that the time needed to control different micro/nano particles in plasma was shorter than that of in water; also the time needed in water was shorter than that of in alcohol.

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 17, Issue 4 (6-2017)
Abstract

The problem of power loss in rotating machinery subjected to the angular misalignment and unbalancing faults are of great importance in relevant industries. Therefore, in this study, evaluation of the power loss and bearing forces of a typical coupling-disk-shaft system with angular misalignment and unbalancing faults is conducted using a novel approach based on the multibody dynamics. In this concern, the flexible coupling is modeled by linear and torsional spring-damper elements. After introducing the model, the kinematic constraints as well as the general form of Euler-Lagrange equations of motion are expressed. Then, the generalized forces are derived in detail. The equations of motion are then solved numerically by the 5th order Runge-Kutta method to evaluate the system power loss. In addition, the effect of angular misalignment and unbalancing faults on the disk displacements as well as the bearing forces are discussed. In the next part of this study, the theoretical results of the power loss are verified experimentally on a faulty simulator system. For measuring the power consumption, a digital power analyzer is used. The results of this research highlight clearly how the power loss is affected by increasing the amount of the system rotational velocity, the angle of misalignment, and the unbalance mass.

Volume 17, Issue 7 (9-2017)
Abstract

In the present study, thermal performance of a microchannel heat sink with superhydrophobic walls is studied for different ratios of the wall convergence. To this end, three-dimensional Navier-Stokes equations and energy equation subject to the slip boundary conditions, viz. velocity slip and temperature jump, are numerically solved using the finite volume method. Then, the variations of thermal resistance of the heat sink with the number of channels, width- and height-tapered ratios, are studied for a fixed pumping power. The results show that by utilizing the superhydrophobic walls, the optimum width-tapered ratio of the channel is higher than that of the hydrophilic walls. The accentuated effect of the number of channels on thermal performance in the presence of liquid-solid interfacial slip weakens the effect of converging the width of the channel. It is also revealed that the optimum number of channels also increases to give prominence to the effect of interfacial slip by diminishing the smallest dimension of the channel. Finally, it is shown that for a pumping power of 0.05 W, using a heat sink with converging microchannels and superhydrophobic walls, reduces the overall thermal resistance by 28 percent, compared to that with conventional microchannels. In fact, the increase in fluid flow rate resulting from the use of converging microchannels with superhydrophobic walls outweighs the undesirable effect of temperature jump on heat transfer, in a sense that the heat sink performance augments considerably.

Volume 17, Issue 98 (April 2020)
Abstract

The purpose of the present research was to investigate four commercial cultivars of tomato (Karoon, 3402, LS0019 and H1015) in order to determine the physicochemical attributes of the cultivar. During this investigation, fruit qualities were evaluated: Soluble solids, total solids, and moisture, pH, lycopene, β-carotene, lutein, and β-cryptoxanthin contents, color indexes (CIE a* b* L*), hue angle (h), chroma (C), total polyphenols and antioxidant activity.The amounts of total solids, a*, b*, L*, carotenoids (lycopene, β-carotene, lutein, β-cryptoxanthin), total polyphenols, and antioxidant activity (Free radical scavenging capacity, reducing power, total antioxidant capacity) remained significantly different among the investigated cultivars (p<0.05). The results showed that the H1015 cultivar had the highest antioxidant activity and carotenoids content especially lycopene. Moreover, this cultivar had the best color indexes (highest a*) in comparison with the other cultivars, it is concluded that the H1015 cultivar is comparable to other cultivars and thus is recommended for cultivation and processing.

Volume 17, Issue 101 (july 2020)
Abstract

Due to the growing demand for biocompatible natural ingredients, the use of hydrocolloids in the food industry is on the rise. Restructured foods are one of the most important aspects of the food industry, involving a complex mix of ingredients, as well as texturing and structuring processes. Achieving an optimal formula for gel formation with appropriate elastic texture can allow for the industrial application in various stuffed products such as olives and related products. Therefore, in this study, gelatin as a gelling agent at 3, 4 and 5 wt% and guar gum as a thickening agent at 0.5 and 1.5 wt% in 1 wt% citric or lactic acid were selected as restructured Ricotta cheese formulation and evaluated of textural properties and shelf-life. Tests included textural characteristics, gel stability, and shelf-life of the restructured cheese. Therefore, the appropriate formula of restructured cheese with appropriate textural properties was selected and evaluated for microbial properties. Due to the importance of sensorial properties of this restructured product, its sensory characteristics were also investigated. Process conditions during storage of samples were also investigated in citric and lactic acid. Finally, the formula containing 4% gelatin and 0.5% guar gum in the solution containing 1% citric acid was selected as the desired sample.

Volume 18, Issue 117 (November 2021)
Abstract

Pectin is a heteropolysaccharide which is widely used as a gelling and stabilizing agent in the food industry. The study aimed to optimize and evaluate the quantity and quality of pectin extraction from apple pomace by acid hydrolysis at high temperatures as a traditional method of the main wastes of the apple juice industries. Extraction efficiency was optimized in the pH from 1.5 to 2, 60 to 90 minutes and 75 to 90 °C by response-surface method (RSM) with using the central composite design. In addition, the esterification degree, amount of galacturonic acid, equivalent weight, methoxyl content, emulsion activity, stability of emulsifier and water/oil holding capacity of pectin were determined under optimal conditions. The results showed that the maximum extraction efficiency (8.83%) was achived at pH 1.5, 90 °C and 90 minutes. The extracted pectin with a degree of esterification of 54% and galacturonic acid 68 mg/g was obtained at optimal conditions. Equivalent weight, methoxyl content, emulsifying activity and water holding capacity of extracted apple pectin were 916, 8.9%, 55.8% and 4, respectively. In overall, it can be possible to obtain different pectin with varying physicochemoical properties with chaning the extraction conditions. Furthermore, the extracted pectin had proper emulsion activity and stability which can be ultilized  in different emulsion based products.

Volume 18, Issue 118 (December 2021)
Abstract

In this research design and manufacture of home baking machine with baking process control is followed. Therefore, the machine is designed and manufactured with the ability to produce an Iranian flatbread at each baking stage. By choosing the heat flux pattern and different thicknesses of the bed and the height of the baking chamber, the temperature and mass distribution in the three areas of the baking bed, bread and baking chamber is obtained. Image processing, texture analysis and sensory tests are used for evaluating of baked bread under different conditions. Geometrical conditions, boundary conditions and patterns of heat flux are the main factors that influence the baking process and quality of bread. The results showed that bed thickness performs better than higher thicknesses. By increasing the height of the chamber at three heights of 2, 4 and 6 cm, the mean temperature of the chamber decreases. Therefore, the height of the 2 cm chamber is the best one. In the study of bread baking with simple apparatus, it was found that the cooking time of 6 minutes and the beginning baking temperature of 160 °C are the most suitable cooking conditions. The porosity of the bread baked is much lower than that of the bakery one. The texture analysis tests showed that the hardness, gumminess, and chewiness of the heat flux pattern profile 22 had the closest values to the control bread

Volume 18, Issue 121 (March 2022)
Abstract

Extensive consumption of confectionery cream and production of products with reduced fat, strengthens the need to replace stabilizing and emulsifying compounds in it. Therefore, in this study, the effect of adding modified basil seed gum (BSG) and rice bran protein isolate (RBP) was investigated. First, the amount of insoluble aggregates and turbidity of basil seed gum solutions and rice bran protein at pH 3, 5 and 7 were investigated. Then, in confectionery creams with 25, 30 and 35% fat content in concentrations of 0.5 and 1% were added and the characteristics of volume increase, foam stability and firmness of confectionery cream were studied as important physicochemical characteristics of cream. The results showed that the highest amount of insoluble accumulations was obtained in basil seed gum at pHs 3 and 5 and the lowest in rice bran protein isolate at pH 7. In contrast, the highest turbidity was observed for RBP at pH 7 and the lowest turbidity in BSG at the same pH. The highest increase in volume and stability of confectionery cream foam was obtained in RBP in 30% fat cream, followed by RBP with 25% fat cream and whey protein containing 35% fat cream. In contrast, the lowest increase in volume was observed in BSG samples.I n contrast, confectionery cream with the highest percentage of fat and the highest amount of basil seed gum had the highest texture firmness. Therefore, according to the results, it is clear that pastry cream with the highest percentage of fat and the least amount of protein can lead to maximum foam stability. Overall, the results showed that RBP has a good ability to be used in confectionery cream formula, although BSG is not able to be used in cream due to lack of protein.

Volume 19, Issue 122 (April 2022)
Abstract

Pectin is used as a coagulant in the food industry due to its thickening properties. Also, the polysaccharide is widely used in the food industry, which is due to its unique technological properties (its gelling properties in the production of jams and like jams such as fruit, etc.).  The aim of this study was to optimize and evaluate the quantitative and qualitative evaluation of pectin extraction from apple pomace by microwave and acid extraction method. Microwave extraction efficiency in the pH range of 1.22 to 1.78, time 10.6 to 17.4 minutes and power 320 to 580 W and by acid extraction method in the pH range of 1.5 to 2, time 60 to 90 minutes and temperature of 75 to 90 °C was optimized by the response surface method (RSM). The results showed that in microwave extraction at pH 1.22, time 17.4 minutes and power 580 W and in acid extraction method at pH 1.5, temperature 90 °C and time 90 minutes maximum extraction efficiency (9.17 and 8.83% respectively) were observed. Also, under optimal microwave extraction conditions, pectin with better quality characteristics (higher degree of esterification, galacturonic acid, equivalent weight, methoxyl content, emulsifying activity and water holding capacity) was obtained than the traditional method.

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