Showing 9 results for Safarpour
Volume 2, Issue 1 (6-2013)
Abstract
Fish fauna at three stations along the Gamasiab River, Kermanshah Province, were investigated for 9 months. Samples were caught using electroshocker and cast net of 1.5 cm mesh size and had their 20 morphometric and 10 meristic characteristics recorded. Twenty three species and subspecies in 14 genera and 5 families were identified, including: minnows (Cyprinidae), sisorid catfishes (Sisoridae), bagrid catfishes (Bagridae), river loaches (Balitoridae) and spiny eels (Mastacembelidae). The highest number of species (18, 78.3%) and genera (10, 71.4%) belonged to Cyprinidae, while 2 species (8.7%) in 1 genus (7.1%) belonged to Balitoridae; the other three families each contained 1 genus and 1 species (4.3%). The lowest species diversity (9 species) was observed in upstream station while the highest diversity (16 species) was in downstream station. Among the identified fish, only Pseudorasbora parva was recognized as exotic and the others were native.
Volume 8, Issue 4 (8-2019)
Abstract
The Xanthomonas citri pv. citri (Xcc) is causal agent of bacterial citrus canker which is major disease of citrus throughout the world. The pthA bacterial effector protein is presented within the infected plants and indispensable of canker. The scFv antibodies are valuable tools for diagnosis and suppression of pathogens within plants. The present article describes developing and characterization of specific recombinant monoclonal scFv antibodies against pthA effector protein. For this aim, the gene encoding pthA protein was heterologously expressed in Escherichia coli and used for screening of Tomlinson phage display antibody library to pinpoint specific single chain variable fragment (scFv). In each round of panning, the affinity of phage towards pthA was checked by enzyme linked immunosorbent assay (ELISA). The data was indicative of about 50% of the monoclonal phages to be reactive strongly against pthA protein. Among the positive clones, 5 samples (A12, B8, C1, H8 and G8) were capable of detecting Xcc-infected plant samples and recombinant pthA protein. Restriction fragment length polymorphism showed similar banding pattern for all 5 scFvs as renamed to pthA-scFG8. HB2151 E. coli cells were infected by the phage bearing pthA-scFG8, and the expression of the peptide was induced by IPTG to produce a 30 kDa recombinant molecule. I-TASSER was used for homology modeling of both scFv and pthA and docking was carried out by Hex program. The latter demonstrated binding energy of −784 kcal/mol in scFv-pthA.
Ehsan Davoodi, Mahmood Mazare, Pedram Safarpour,
Volume 16, Issue 10 (1-2017)
Abstract
This paper presents the control of a quadrotor using nonlinear approaches based on the experimentally measured sensors data. The main goal is the control and closed loop simulation of a quadrotor using feedback linearization and sliding mode algorithms. First, a nonlinear model of quadrotor is derived using Newton-Euler equations. To have a more realistic simulation the sensors noise performance were measured using a setup. sensors data was measured under on engines. Since the experimental data for sensor had error and noise, a Kalman filter was used to reduce sensors noise effect. Results demonstrate good performance for Kalman filter and controllers. Results showed that feedback linearization and sliding mode controllers performance was good but angles changes were smoother on feedback linearization controller. With increasing uncertainty, feedback linearization performance was away desired mode from this aspect The time to reach the goal situation while increasing uncertainty was no significant impact on the performance of sliding mode controller.Thus feedback linearization controller added PID is Appropriate to Maintain the quadrotor attitude while sliding mode controller has better performance to angles change and transient situations.
Masoud Nourimotlagh, Pedram Safarpour, Mehdi Pourgholi,
Volume 16, Issue 12 (2-2017)
Abstract
The purpose of this article is dynamic modeling of a quadrotor and control of its Roll and Pitch angles based on the experimentally measured sensors data. So, after driving nonlinear model of quadrotor equations, the control of the quadrotor’s angular situation was simulated using PID and feedback linearization algorithms. Due to the widespread application of MEMS sensors in measuring the status of various systems and to have a more realistic simulation, sensors data was measured and used in simulation of controllers. Due to errors of MEMS sensors, vibration of motors and airframe, being noise on outputs, Kalman filter was used for estimation of angular situation. As one of the purposes of this paper was the use of its results in actual control of a quadrotor, motor model was used to determine PWM control signals. The results obtained from simulation in Simulink showed good performance of both controllers in controlling roll and pitch angles.
Meysam Elyasi, Vahid Fakhari, Pedram Safarpour,
Volume 18, Issue 6 (10-2018)
Abstract
Today, with increasing consumption of non-renewable energy sources, scientists are looking for an alternative for these resources. The Stirling engine is one of the ideas that have recently attracted engineers' attention. The purpose of this study is to optimize the output power and stability of a beta type free-piston Stirling engine. In this regard, at first by deriving the thermodynamic and dynamic equations of the system and combining them, the governing equations are obtained including the nonlinear function of the pressure loss in heat exchangers. The governing nonlinear equations are solved and for the purpose of validation, simulation results obtained in this study are compared with experimental and simulation results presented in the literature. In free-piston Stirling engines, increasing the output power by keeping their stability is very important. Therefore, by performing parametric study, the parameters with more effects on the output power and stability are determined and considered as optimization variables. In order to perform multi-objective optimization of output power and stability of the free-piston Stirling engine, a proper objective function is selected and one of the methods in genetic algorithm is employed using optimization software Modefrontier. Finally, values of variables, before and after optimization and also, percentage of improvements in output power and stability of the free-piston Stirling engine are presented.
Vahideh Vahidifar, Mostafa Taghizadeh, Vahid Fakhari, Pedram Safarpour,
Volume 18, Issue 9 (12-2018)
Abstract
In this paper, control position of a pneumatic actuator with the PWM solenoid on/off valves using two different pneumatic circuits performed. After deriving the governing dynamic equations, to investigate the circuit effect on system performance, mentioned two pneumatic circuits are introduced. Then in order to control the position of the pneumatic actuator, for both circuits, sliding mode and proportional-integral-derivative controllers are designed. In proceeding, optimum controller parameters are determined by genetic algorithm to achieve minimum control energy and position error. Finally, by performing simulations in Matlab Simulink, performance of designed controllers with optimal parameters is evaluated and compared in the presence of disturbance. According to the obtained results, by comparing the performance of two circuits, it is observed that the first pneumatic circuit with two solenoid valves can track the high-frequency sine reference input better and more precisely in the presence of a nonlinear sliding mode controller. The position tracking error in low-frequency sine reference input using a classic proportional-integral-derivative controller, for a single-valve pneumatic circuit is considerably less than that of a pneumatic circuit of two valves. This indicates the input-output quasi linear behavior of the pneumatic actuator in a single-valve circuit.
J. Aghayari, P. Safarpour, A. Rahi, S. Bab,
Volume 20, Issue 2 (February 2020)
Abstract
In this paper, the application of passive vibrational linear absorber on the indirect reduction of blade vibrations using its mounted on the disk-blade system is studied. The absorber receives the vibration energy of blade through a structural coupling of the disk with blade and losses it by its linear damping. Due to cyclic symmetry, the analysis of the bladed disk is reduced to the number of DOFs in a single sector. A cyclic transformation from physical to modal coordinates is used to perform this reduction. Natural frequencies and forced responses of the system are obtained by solving the characteristic and algebraic equations, respectively. The case study of a steam turbine includes 259 blades in 37 packets of 7 connected blades attached to the perimeter of the disk. Cyclic symmetric finite element analysis at 3000rpm is used to extract the natural modes and frequency diagram of the system. A two DOFs reduced-order model is identified for modeling the frequency-veering region. This region has been formed between the first and second families of natural modes and there is a strong coupling between them in this region. In addition, this region is close to the system excitation line and the possibility of resonance exists. Therefore, some linear energy absorbers are mounted on the disk for the indirect vibration reduction of blades. The initial optimal parameters were determined for the first and second modes using Den Hartog relations. These parameters reduced the system vibrations and they were used in subsequent optimization. The optimization has resulted in the improvement of absorber performance exclusively around the second mode, in compare with the tuned system by Den Hartog relations.
Volume 20, Issue 135 (May 2023)
Abstract
Sunflower oil is one of the most important vegetable oils with high nutritional value, which is unfortunately sensitive to oxidation due to unsaturated fatty acids. In this study, sage leaf extract was obtained using ultrasound bath and ethanol solvent: water (70:30) at 35 ° C for 30 min at 35 KHz. The total phenolic content of extract was 31.12 mg GA/g. Antioxidant activity of 50, 100, 200 and 250 ppm of sage extract was measured by beta-carotene/linoleic acid bleaching assay and oxidative stability index. The results showed that increasing in the concentration of extract increased the antioxidant activity and oxidative stability index. Sage extract (250 ppm) was used for encapsualtion in the wall of qadomehshahri seed gum/whey protein isolate at 1: 0, 1: 1 and 0: 1 ratio. The particle size of the nanocapsule varied between 217.4 and 0.270 nm, and the nanocapsule prepared withqodomehshahrihad the largest size and the nanocapsule prepared with composition of gum and protein isolate had the smallest size. In order to intensify the oxidation process, sunflower oil without antioxidants, oils containing free extracts and TBHQ was placed in an oven at 60 ° C for 24 days. Peroxide, para-anisidine and Totox value of the samples were measured. The results showed that oil oxidation in samples containing encapsulated extract was less than the control, and oil containing free extract and TBHQ. At the end of storage time, the peroxide and paraanisidine value in oil samples containing encapsulated extract was less than oil containing synthetic TBHQ antioxidant and free extract. Also, among the walls used for encapsulating of sage extract, a composite wall made of qodomehshahri seed gum and whey protein isolate is the best coating for encapsulation the extract to increase the shelf life of sunflower oil.
Volume 22, Issue 4 (Winter 2019)
Abstract
With economic development and population growth, the global need for energy is increasing steadily. Fossil fuels are the most commonly used fuel in the world, but their resources are limited. Therefore, for sustainable development, the need to use renewable energy sources is felt more than ever. Solar energy recognized as the most important and most affordable one. In Iran, the availability of suitable climate and sunlight in many areas and seasons has provided a good basis for using this kind of energy. The purpose of this research is to utilize a MCDM approach for evaluating the potential of different regions in Qazvin province for the establishment of a solar power station. In this regard, several evaluation criteria were identified and their importance was determined by the AHP method and then their uncertainty is modeled using fuzzy theory. Then, a potential map was developed using OWA and TOPSIS methods. Finally, the result of utilizing AHP-OWA method is compared with AHP-TOPSIS. Comparison of the weights of indicators shows the weather factors as important ones. In addition, according to the research findings, the Takestan region was recognized as a good area for establishing a solar power plant. Based on previous studies, construction of a 100MW solar power station in this area has been confirmed. This means that the proposed method is acceptable to be used by decision-makers as an effective tool.
