r ghasemi

The design of a flying vehicle autopilot poses a significant challenge to the controller performance and the effectiveness of the flight control system. This challenge arises from uncertainties and extreme variations in parameters. To enhance the performance of the flight autopilot, the application of adaptive control techniques becomes crucial. Flight control systems extensively employ adaptive control methods due to their capacity to swiftly and automatically adapt to environmental changes and system dynamics, consequently achieving greater speed and accuracy. This paper aims to simulate scenarios where in the flight control system of an flying vehicle approach, with a specific focus on aerodynamic control in the roll, pitch, and yaw channels. The main purpose of the paper is to be able to provide an adaptive flight control system that can perform properly in the face of sharp and sudden changes in parameters. The paper compares the performance of the multiple model adaptive control method, particularly the switching and tuning technique, for the autopilot's roll, pitch, and yaw with other methods such as the reference model adaptive control used in previous research. The results demonstrate the superiority of the multiple adaptive controller utilizing switching and tuning techniques in handling parameter changes, exhibiting faster and more responsive behavior compared to traditional adaptive controllers.

The purpose of this article is to control the formation and pass static and dynamic obstacles for the quadrotor group, maintain the continuity and flight formation after crossing the obstacles, and track the moving target. Model Predictive Control (MPC) method has been used to control the status and position of quadrotors and formation control. Flight formation is based on the leader-follower method, in which the followers maintain a certain angle and distance from the leader using the formation controller. The improved Artificial Potential Field (APF) method has been used to pass obstacles, the main advantage of which compared to the traditional APF is to increase the range of the repulsive force of the obstacles, which solves the problem of getting stuck in the local minimum and not passing through the environments full of obstacles. The results of the design of the attitude and position controller showed that the quadrotors were stabilized and converged in less than 3 seconds. Formation control simulations in the spiral path showed that the followers, follow the leader. The results of the quadrotors passing through the obstacles were presented in four missions. In the first mission, 4 quadrotors crossed static obstacles. In the second mission, 4 quadrotors crossed dynamic obstacles. In these two missions, the quadrotors maintained a square flight formation after crossing the obstacles. In the third mission, the number of quadrotors increased to 6. The leader tracked the moving target and the quadrotors crossing the static obstacles.  In the last mission, the quadrotors passed through the dynamic obstacles and the leader tracked the static target. In these missions, the quadrotors maintain the hexagonal formation after crossing the obstacles. The results simulations showed that the quadrotors crossed the fixed and moving obstacles and after crossing, they preserved the flight formation.

The purpose of this paper is obstacle avoidance and moving target tracking for a quadrotor. Solving the obstacle crossing problem for the quadrotor includes two parts. The first part is controlling the attitude and position. The second part is path planning to pass obstacles. In this paper, the attitude and position of the quadrotor are controlled by super-twisting sliding mode control (SMC) and non-singular terminal super-twisting SMC. The simulation results of these two methods were compared. In the non-singular terminal ST-SMC method, the convergence time was approximately 5% less than the super-twisting SMC method. Also, the non-singular terminal ST-SMC method has more ability to remove disturbances. Because of the better results, the non-single terminal ST-SMC was used to control the position and attitude of the quadrotor to cross obstacles and track the target. In the second step, to cross obstacles, the potential field path planning algorithm is used. This method is a combination of attraction towards the target and repulsion from obstacles. The results of the simulation of crossing the obstacles were presented in four missions. In the first mission, the obstacles and the target are static, and in the second mission, the obstacles are static, and the target is moving. In the following, the obstacles and the target are dynamic; in the last mission, a combination of static and dynamic obstacles is considered, and the target is moving. The simulation results of four missions show that the quadrotor does not hit obstacles and reaches the desired goal, till the applied method is successful.

Uranium compounds are toxic and radioactive. Its poisonous properties can be fatal. So, it is necessary to prevent its excessive entry into nature due to uranium's chemical toxicity and radioactivity. Waste from industrial-nuclear centers also has different amounts of uranium; therefore, the removal of this element from the effluent of these centers is essential. On the other hand, due to the importance and limited resources, uranium recovery from waste has economic value. In the present study, the Response Surface Method (RSM) based on the central composite design was used to evaluate and optimize different parameters affecting the bioremediation process of Shewanella RCRI7 in real waste. The proposed second-order model with a correlation coefficient R2 = 0.94 appropriately predicted the experimental data and the maximum uranium reduction efficiency by Shewanella RCRI7 under optimal conditions (pH = 5.7-6.5, Temperature 26.63 °C and Time 117 hours) was estimated to be about 98%. In the next step to interact between the variables, three-dimensional procedures with pH and temperature; temperature and time; pH and time interactions were obtained; finally, the uranium reduction in real effluent was investigated by XRD and spectrophotometric methods. Based on the results, Shewanella RCRI7 is determined as a valuable candidate for uranium bioreduction processes in the determined industrial wastewater. On the other hand, using the response surface methodology can provide a comprehensive understanding of the process, the mechanism of uranium bioremediation by Shewanella RCRI7, and the theoretical support for this process.

Soil classification in a standard system is usually defined based on information obtained from properties and their variations in different map units. The aim of this study was to compare soil genesis and morphological characteristics in different landforms with WRB and Soil Taxonomy (ST) Systems. From nine studied profiles, six profiles were selected as representative profiles and dug in Colluvial fans, Piedmont plain, and Alluvial plain physiographic units, respectively. Then, the soils were classified according to the pattern of the two systems. Also, variation analysis of variance (ANOVA) and comparing means were used to quantify interested soil properties. The results of soil physio-chemical properties at different landform positions were significant based on analysis of variance of the effect of physiographic units and soil depth at the level of 1 %. Soil classification results based on WRB indicated that WRB were recognized four reference soil groups (RSG) included Regosols, Cambisols, Calcisols, and Gleysols at the first level of WRB classification in comparison of ST with recognizing two order Entisols and Inceptisols could separate more soils. The soils were located on the alluvial plain with a high groundwater level in the WRB due to the creation of restrictive conditions for root development in contrast to the ST called “Aquepts” in the suborder level but in a WRB is classified as the “Gleysols” RSG. On the other hand, ST, unlike WRB, used the Shallow criteria at the family level to describe the shallowness of soils and the limitations of root development. Generally, the efficiency of each system varies despite the differences in their structure and depending on the purpose of using them.

Ammonium Hydroxide production ‎unit (AHPU) is one of the widely ‎used and important units available in ‎many ‎industries such as oil and gas, ‎petrochemical, and power plants. In ‎this research, for the first time, a ‎detailed systematic inspection and ‎maintenance plan for AHPU ‎is ‎determined based on the ‎prioritization of equipment using ‎equipment’s risk analysis. ‎Equipment’s failure risk is ‎calculated ‎based on probability and ‎consequence of failure according to ‎American Petroleum Institute ‎Recommended Practice (API RP) 581. ‎Different ‎maintenance strategies were ‎designed and compared considering ‎several criteria like safety, cost, and ‎feasibility using the analytic hierarchy ‎process. Then risk-based optimal ‎maintenance policy for each group of ‎equipment ‎was identified. Finally ‎results showed that, the equipment ‎identified as high or medium to high ‎risk level such as liquid ‎ammonia ‎storage tank and its related ‎pipes, should has preventive ‎maintenance with an inspection ‎period of 48 months. While for the ‎medium risk equipment such as ‎ammonium hydroxide storage ‎tank ‎and low-risk equipment such as ‎ammonia absorption tank, should ‎have corrective maintenance with ‎inspection period of 72 and 90 ‎months, respectively‎.

In this study, E-glass/epoxy laminated composites with [0]12 stacking sequence manufactured by hand lay-up method. Afterwards, by considering the most important input parameters of the micro-drilling process including tool rotational speed, feed rate and tool diameter, the statistical mathematical modeling is performed to accurately investigate the thrust force response behavior versus the mentioned variables. For this purpose, using full factorial experimental design and response surface methodology and performing 54 experimental tests and considering repeatability of experiments in order to improve modeling accuracy, a second-order linear regression equation has been obtained. Also, by using the Sobel sensitivity analysis method, the quantitative effect of force behavior sensitivity versus input parameters is investigated. Moreover, the Derringer optimization algorithm is used to achieve the minimum amount of thrust force in micro-drilling process of laminated composites. The results of the statistical analysis show that the lowest feed rate, maximum tool rotational speed and smaller diameter lead to produce lowest thrust force of laminated composites. The Sobol sensitivity analysis shows that the diameter of the tool (57.8%), the feed rate (24.4%), and the rotational speed (17.8%) will have the greatest effect on thrust force in micro-drilling process, respectively. Finally, the optimization analysis show that, the lowest thrust force was obtained at a rotational speed of 2515 rpm, a feed rate of 10 mm / min and a tool diameter of 0.5 mm.

To investigate the effects of newly introduced probiotic, prebiotic, and synbiotic, 1080 d-old broiler chickens were used in a completely randomized design with six treatments and six replicates of 30 birds each. Dietary treatments were: basal diet (control), basal diet plus 500 g of probiotic/ton (Probiotic-500), basal diet plus 500 g and 300 g of probiotic/ton during days 0-24 and 25-42 of age, respectively (Probiotic-500-300), basal diet plus 300 g of probiotic/ton (Probiotic-300), basal diet plus 1 kg of prebiotic/ton (Prebiotic), basal diet plus 1 kg of synbiotic/ton (Synbiotic). Average daily weight gain and feed conversion ratio were only affected by dietary treatments during the starter period; the lowest average daily weight gain and the highest feed conversion ratio were recorded for the control treatments compared to the others. The antibodies titers (total, IgG, and IgA) against sheep red blood cells, and Newcastle and Influenza viruses were significantly (P < 0.05) increased by feeding diets containing all experimental additives compared with the control diet. The pH of the ileum decreased (P < 0.05) by using probiotic, prebiotic, and synbiotic in the diets. The highest number of lactobacillus and E. coli populations was observed in birds fed synbiotic and control diet, respectively. The height of villus in the jejunum and its ratio to crypt depth was higher in birds fed a symbiotic diet compared to birds fed probiotic or control diets (P < 0.05). Furthermore, the cecum concentration of short-chain fatty acids was greater in chickens fed diets containing probiotic, prebiotic, or synbiotic than the control chickens (P < 0.05). In conclusion, although dietary supplementation with probiotic, prebiotic, and synbiotic had no positive effect on growth performance parameters of broiler chickens, the use of these products could exert promising effects on poultry health.

Application of agricultural residue biochars as an adsorbent is one of the most cost-effective and widely used methods to remove contaminants such as phosphate from water resources. In fact, the bagasse is the waste residues of sugar cane which is abundant in southern parts of Iran. The aim of this study was to investigate the kinetics of phosphate adsorption by bagasse biochar and determine the best kinetic model to interpret this phenomenon. After determining optimal pH, the effects of initial phosphate concentration and contact time on phosphate adsorption by sugarcane bagasse biochar were investigated and 7 kinetic models were used to study the patterns of P adsorption. Maximum adsorption obtained at the time of two hours. Kinetic models of the exponential function, parabolic diffusion, Elovich and first order reaction were compatible with the results but the exponential function model was the best. The half-life of phosphate adsorption in different concentrations varied from 30 minutes to 100 minutes and decreased with increasing initial P concentration. P adsorption rate constants increased as initial concentration of phosphate increased. High values of P adsorption parameters demonstrated that the sugar cane bagasse biochar could be used as an appropriate adsorbent for phosphate removal from aqueous solutions.

In order to investigate the effect of sodium chloride application, organic matter sources and growth promoting bacteria on fresh and dry matter yield and concentration of micro nutrients in shoot of spinach, a factorial experiment was conducted in a completely randomized design with three replications. The treatments were sodium chloride (control (S0), 2 (S2) and 4 (S4) g Na Cl kg-1 soil), organic matter (control (OM0), 0.5% and 1.0 % rice husk and 0.5% and 1.0 % rice husk biochar, w/w)  and PGPR bacteria (without and with bacteria). Results showed that application of 2 and 4 g salt kg-1 of soil slightly increased iron concentration of aerial part, while Cu concentration increased by 48.10% and 48.32%, respectively. However, Zn and Mn concentrations decreased. Plant yield was not affected by salinity, probably due to the osmotic adjustment resulting from gradual increase in salt addition. Application of organic matter sources increased spinach fresh and dry weight, and Fe, Zn, Cu and Mn concentrations. Inoculation with Pseudomonas fluorescence significantly increased fresh and dry weight as well as Fe, Zn, Cu, and Mn concentrations in aerial part, compared with the related control (without bacteria(. In conclusion, spinach (cv Virofly) very well tolerated gradual addition of salinity; and application of organic matter with growth promoting bacteria increased micronutrients concentration and growth of spinach in a calcareous soil affected by salinity.

This paper suggests a decentralized adaptive sliding mode formation procedure for affine nonlinear multi-quadrotor under a fixed directed topology wherever the followers are conquered by dynamical uncertainties. Compared with the previous studies which primarily concentrated on linear single-input single-output (SISO) agents or nonlinear agents with constant control gain, the proposed method is applied on affine nonlinear agents with nonlinear control gain such as the quadrotor. This designing procedure overcomes the problem of unknown nonlinear affine functions of the quadrotors. Fuzzy systems are engaged both to compensate recursively the unknown nonlinear functions and to apply the expert’s knowledge on the formation technique. On-line updating the controller parameters, achieving the formation of quadrotor, boundedness of all signals involved in the closed loop of the quadrotor, and chattering reduction are the focal features of the proposed formation methodology. To demonstrate the persistency and efficiency of the methodology, a numerical example of the multi-quadrotor system is considered in this paper.

In this paper, a new design is proposed for a neural-sliding mode controller for a certain class of permanent-magnet synchronous motors to employ in unmanned submarines. Using presented specifications; first, the intended motor is designed and simulated in the Maxwell full-wave software based on the finite element method. Then, the nonlinear model is derived by the neural network using the data obtained from the simulation of the motor in the software. Since the model-based control methods are expensive and error-prone due to the high dependence on the modeling as well as the use of sensors, a sensorless controller is used, and with respect to the proposed nonlinear method, a sliding mode controller is designed for this particular motor. The proposed neural-sliding controller has obtained better results than the PID controller due to its robustness against system uncertainties and external disturbances, the overall closed-loop stability and convergence of error-trace to zero. The simulation results confirm the proper performance of the proposed model and controller.

This paper presents the design of a thermionic electron gun with two different geometries, flat cathode and spherical cathode.The purpose of this research is to answer the question of which type of electron gun is suitable for industrial electrostatic accelerators. CST Studio software was used to design the guns. The desired specification in the design of a suitable thermionic gun, the maximum current  of  50 milliamper and the voltage 5 to 10 kilovolt, is selected for use in the dynamitron accelerator. The beam current, the waist beam radius, the waist beam position and the perveance of a flat cathode gun and spherical cathode gun were 49 and 49.8 mA, 3.2 and 0.45 mm, 36 and 24.3mm, 0.138 and 0.0498 μperv, respectively. Since the electron guns used in the industry have a perveance between 0.1 to 1 μperv therefore, an electron gun with a flat cathode with 0.138 μperv is more suitable.  On the other hand, it is easier and less costly to make it. That is why the gun with a flat cathode was chosen and its final dimensions are presented.

In order to investigate the effects of application of sodium chloride, organic matter, and growth promoting bacteria on fresh and dry shoot weights and also concentration of some nutrients in aerial parts of spinach, a factorial experiment was conducted in a completely randomized design with three replications.  The treatments consisted of three levels of sodium chloride (control (S0), 2 (S2) and 4 (S4) g Na Cl kg-1 soil equivalent to 0.7, 8 and 16.8 dS/m, respectively), five levels of organic matter (control 0%(OM0), 0.5% (RS0.5) and 1% (RS1) % rice husk and 0.5% (Bi0.5) and 1% (Bi1) % rice husk biochar, w/w)  and two bacterial levels i.e. without (P0) and with bacteria (P1). Results showed that increasing salinity levels significantly increased spinach dry weight, but significantly decreased concentrations of N, P, Ca and Mg in aerial part, while concentration of Na increased. With the use of organic matter sources, fresh and dry weights of spinach shoot and con fluorescence [H1] centration of all nutrients increased significantly. Also, addition of Pseudomonas fluorescence significantly increased fresh and dry weights and concentration of nutrients of spinach aerial part .According to the results obtained in this study, it can be concluded that the use of organic matter as a soil amendment and rich source of nutrients can greatly increase concentration of nutrients in spinach. Also, addition of Pseudomonas fluorescence as a biofertilizer can improve spinach growth and increase concentration of some nutrients in spinach aerial part under salinity conditions. Application of organic matter and bacteria in salinity-free conditions increased concentration of nutrient and yield of plant. In general, further investigations under field conditions are necessary to verify the results of the present study.  [H1]?

In this research, the analysis of the effects of circular hole and thermal cycle fatigue on the mechanical properties in multi-layer polymer composite reinforced with nanoparticles are investigated. First, multi-walled carbon nanotubes with 0.1% weight fraction of nanoparticles are added to the epoxy resin ML506. The. In order to homogenize particle in the resin, it is mixed with a magnetic stirrer for 30 minutes. The material is placed in an ultrasonic device for 40 minutes to homogenize the resin and nanoparticle completely. The resin reinforced with glass fibers constitute symmetric cross ply laminates stacking sequence [02/902]s, and nanocomposite samples are made with hand layup method. In this study, open-hole specimens with diameter of 2 and 4mm are investigated. To study the thermal cycles, nanocomposite samples of 3 levels of thermal cycles including 0, 180, and 360 cycles were investigated. The samples are exposed to a temperature range of 0 to 100oC. After that, the specimens undergo tensile testing. Using the tensile test, the modulus of elasticity and tensile strength are compared for the different thermal cycles and the diameter of the holes. By increasing the number of thermal cycles, the tensile strengths of nanocomposite samples are not significantly changed. Also, with increasing the diameter of the hole, the tensile strength is decreased. The elasticity modulus with increasing thermal cycles for all specimens have been minimal changes. Also, a linear regression model was developed, using MINITAB software for strength and elastic modulus in terms of number of thermal cycles and diameter to width ratio.

Research is one of the most influential tools for developing students’ potential talents. This study aimed to assess students’ awareness, attitude, and performance regarding researching activities in the Urmia University of Medical Sciences.

Totally, in this descriptive-analytic study, we randomly selected 70 male and female students of medicine. They were (35 male and 35 female) between 21 and 36 years old. Likert question type inventories were used to determine students’ awareness and attitude toward the importance of research and their performance in this case. Findings were presented based on descriptive data analysis and tests.

The sum of positive responses to the question: “Are you interested in researching activities?” were 52 (74.3%) and the rest 18 students (25.7% of all test subjects) responded negatively. When they were asked: “Do you have enough time for researching activities?” the answer of 16 students (22.8%) was positive versus 54 (77.2%) of negative responses. Totally 8 students (11.4% of all test subjects) believed that there are enough lab equipment and facilities available. However, 48 students (68.6% of all test subjects) believed otherwise, and 14 students (20%) had no idea in this case. The research performance of students was evaluated as follows: poor for 35 students (50%); moderate for 28 students (40%); good for 5 students (7.1%) and excellent for 2 students (2.9%). The total average of attitude appraisal value was 77.85% for all 70 students.

The majority of students has plenty of time for doing research and do not have living and occupational difficulties. The lack of proper informing policy and integrated motivating programs are the cause for the lack of interest toward researching activities among students.