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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Journal of Renewable Energy and Environment
- نوع مقاله: Journal Article
- کلمات کلیدی: fuzzy logic,Static synchronous compensator,Microgrid,Frequency Control
- چکیده:
- چکیده انگلیسی: In this paper, the effect of a static synchronous compensator (STATCOM) influence on the frequency of islanded microgrids based on frequency control using fuzzy cooperative control is investigated. To achieve fast frequency control, instantaneous power balance between generation and consumption is inevitable, and it can be supplied through energy storage systems such as battery with a proper frequency control method. Besides, the frequency control of islanded microgrids could be studied under different circumstances, where one aspect analyzed is added to a flexible AC transmission system (FACTS) device, such as STATCOM, in the microgrids. Although STATCOM is charged with improving the voltage profile, it can affect frequency stability by adjusting the voltage very quickly. Due to the importance of refining frequency stability, two controller methods are compared: a classic PI controller and a fuzzy PID controller. Accordingly, the performance of STATCOM is evaluated via two scenarios. Based on simulation results, by applying the fuzzy PID controller to the microgrid, STATCOM can reach the nominal frequency. Moreover, with greater validation and investigation of this topic, this device could be an agreeable alternative to the battery energy storage system (BESS).
- انتشار مقاله: 15-03-1398
- نویسندگان: Maryam Rahmani,Faramarz Faghihi,Hassan Moradi CheshmehBeigi,Seyed Mehdi Hosseini
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Biotechnology
- نوع مقاله: Journal Article
- کلمات کلیدی: Escherichia coli,TEM,SHV,AmpC,β-lactamases and PCR Typing
- چکیده:
- چکیده انگلیسی: Fifty clinical isolates of Escherichia coli from two groups of subjects (hospitalized and outpatients) were
studied for their susceptibility to twelve β-lactam antibiotics. All isolates were resistant to ampicillin, amoxicillin, oxacillin and cefradine. Carbenicillin resistance was found in all but one outpatient isolate. Resistance to cephalothin, cephalexin and cefazoline ranged from 76% to 96% among the test bacteria. On the other hand, the majority of the isolates were sensitive to cefoxitime, ceftizoxime and ceftriaxone (84-100%). β-lactamases from all bacteria were inhibited by clavulanic acid and none harbored extended spectrum β-lactamases as shown by the double disc diffusion method. Gene amplification by polymerase chain reaction (PCR) using specific primers for AmpC, TEM and SHV enzymes showed that 92% of all organisms carried blaTEM alone, or along with SHV or ampC genes. Presence of all three genes was shown in 8% of the hospitalized patients and 20% of the outpatients. Conjugative transfer of β-lactam resistance markers into susceptible host recipients occurred for 72% of the isolates in each group. Overall, the antibiotic susceptibility profile, the distribution of the β-lactamase gene type and the rate of conjugative transfer of the resistance markers were similar in both subject groups.- انتشار مقاله: 12-10-1383
- نویسندگان: Fereshteh Eftekhar,Seyed Mehdi Hosseini-Mazinani,Soheila Ghandili,Minoo Hamraz,Shahrzad Zamani
- مشاهده
- جایگاه : پژوهشی
- مجله: Control and Optimization in Applied Mathematics
- نوع مقاله: Journal Article
- کلمات کلیدی: Homotopy Perturbation Method,Damping,Suboptimal control,Harmonic oscillator
- چکیده: مسأله نوسانگر هارمونیک کنترل شده با دمپینگ، دستهی مهمی از مسائل کنترل بهینه است، که نقش مهمی در زمینه پدیده نوسانی در سیستمهای مهندسی غیرخطی ایفا میکند. در این مقاله، برای حل این مسأله، روش تحلیلی ارائه میشود. این رویکرد بر اساس روش اختلال هموتوپی پایه ریزی شده است. فرایند حل آسان و ساده است. برای این منظور، یک الگوریتم طراحی کنترل با پیچیدگی محاسبات کم، پیشنهاد میشود. هم چنین، به کمک تکرارهای متناهی از الگوریتم پیشنهادی، یک قانون کنترل زیر بهینه برای مسأله به دست میآید. در نهایت، نتایج به دست آمده با جواب دقیق مسأله نوسانگر هارمونیک و سایر نتایج حاصله از آثار قبلی مقایسه شده، که به وضوح، دقت بالای نتایج آشکار است.
- چکیده انگلیسی: The controlled harmonic oscillator with retarded damping, is an important class of optimal control problems which has an important role in oscillating phenomena in nonlinear engineering systems. In this paper, to solve this problem, we presented an analytical method. This approach is based on the homotopy perturbation method. The solution procedure becomes easier, simpler and more straightforward. In order to use the proposed method, a control design algorithm with low computational complexity is presented. Through the finite iterations of the proposed algorithm, a suboptimal control law is obtained for the problems. Finally, the obtained results have been compared with the exact solution of the controlled harmonic oscillator and variational iteration method, so that the high accuracy of the results is clear.
- انتشار مقاله: 12-10-1396
- نویسندگان: Seyed Mehdi Mirhosseini-Alizamini,Seyed Mehdi Mirhosseini-Alizamini,Seyed Mehdi Mirhosseini-Alizamini
- مشاهده
- جایگاه : پژوهشی
- مجله: Computational Methods for Differential Equations
- نوع مقاله: Journal Article
- کلمات کلیدی: traveling wave solutions,Nonlinear evolution equation,Tzitzica type evolution equations,New extended direct algebraic method
- چکیده:
- چکیده انگلیسی: In this study, the new extended direct algebraic method is exerted for constructing more general exact solutions of the three nonlinear evolution equations with physical interest namely, the Tzitzeica equation, the Dodd-Bullough-Mikhailor equation and the Liouville equation. By using of an appropriate traveling wave transformation reduces these equations to ODE. We state that this method is excellently a generalized form to obtain solitary wave solutions of the nonlinear evolution equations that are widely used in theoretical physics. The method appears to be easier and faster by means of symbolic computation system.
- انتشار مقاله: 09-02-1397
- نویسندگان: Seyed Mehdi Mirhosseini-Alizamini,Hadi Rezazadeh,Mostafa Eslami,Mohammad Mirzazadeh,Alpert Korkmaz
- مشاهده