Harmonic Elimination and Optimization of Stepped Voltage of Multilevel Inverter by Bacterial Foraging Algorithm

Salehi, Reza,Vahidi, Behrooz,Farokhnia, Naeem,Abedi, Mehrdad The Korean Institute of Electrical Engineers 2010 Journal of Electrical Engineering & Technology Vol.5 No.4

A new family of DC to AC converters, referred to as multilevel inverter, has received much attention from industries and researchers for its high power and voltage applications. One of the conventional techniques for implementing the switching algorithm in these inverters is optimized harmonic stepped waveform (OHSW). However, the major problem in using this technique is eliminating low order harmonics by solving the nonlinear and complex equations. In this paper, a new approach called the "bacterial foraging algorithm" (BFA) is employed. This algorithm eliminates and optimizes the harmonics in a multilevel inverter. This method has higher speed, precision, and convergence power compared with the genetic algorithm (GA), a famous evolutionary algorithm. The proposed technique can be expanded in any number of levels. The purpose of optimization is to remove some low order harmonics, as well as to ensure the fundamental harmonic retained at the desired value. As a case study, a 13-level inverter is chosen. The comparison results by MATLAB software between the two optimization methods (BFA and GA) have shown the effectiveness and superiority of BFA over GA where convergence is desired to achieve global optimum.

Elimination of Low Order Harmonics in Multilevel Inverters Using Genetic Algorithm

Salehi, Reza,Farokhnia, Naeem,Abedi, Mehrdad,Fathi, Seyed Hamid The Korean Institute of Power Electronics 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.2

The selective harmonic elimination pulse width modulation (SHEPWM) switching strategy has been applied to multilevel inverters to remove low harmonics. Naturally, the related equations do not have feasible solutions for some operating points associated with the modulation index (M). However, with these infeasible points, minimizing instead of eliminating harmonics is performed. Thus, harmful harmonics such as the $5^{th}$ harmonic still remains in the output waveform. Therefore, it is proposed in this paper to ignore solving the equation associated with the highest order harmonics. A reduction in the eliminated harmonics results in an increase in the degrees of freedom. As a result, the lower order harmonics are eliminated in more operating points. A 9-level inverter is chosen as a case study. The genetic algorithm (GA) for optimization purposes is used. Simulation results verify the proposed method.

Validity and Reliability of the World Health Organization Disability Assessment Schedule 2.0 36-Item Persian Version for Persons with Multiple Sclerosis

Reza Salehi,Hossein Negahban,Farzad Faraji Khiavi,Shiva Saboor,Nastaran Majdinasab,Kamal Shakhi 대한가정의학회 2020 Korean Journal of Family Medicine Vol.41 No.3

Background: No previous studies have assessed the psychometric properties of the 36-item version of the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) in the Persian language of Iran. This study was designed and conducted to evaluate the validity and reliability of the Persian version using a sample of persons with multiple sclerosis in Ahvaz, Iran. Methods: The methodological study was conducted in two stages: First, the 36 items of the original WHODAS 2.0 were translated to create a Persian version, after which the translation validity and psychometric properties were tested. The factor structure of the instrument was also tested using exploratory and confirmatory factor analyses. Results: The intraclass correlation coefficients were very good to excellent, varying between 0.82 and 0.99 for the six domains, and all domains had Cronbach’s α reliability values of above 0.70. For construct validity, results showed negative and strong correlation between the total score of WHODAS 2.0 and the Multiple Sclerosis Quality of Life- 54. Exploratory factor analysis divided the Persian version of WHODAS 2.0 into seven factors for multiple sclerosis patients. Conclusion: The results of this study indicate that the Persian version of WHODAS 2.0 is a valid and reliable instrument to study the disabilities of people with multiple sclerosis.

Elimination of Low Order Harmonics in Multilevel Inverters Using Genetic Algorithm

Reza Salehi,Naeem Farokhnia,Mehrdad Abedi,Seyed Hamid Fathi 전력전자학회 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.2

The selective harmonic elimination pulse width modulation (SHEPWM) switching strategy has been applied to multilevel inverters to remove low order harmonics. Naturally, the related equations do not have feasible solutions for some operating points associated with the modulation index (M). However, with these infeasible points, minimizing instead of eliminating harmonics is performed. Thus, harmful harmonics such as the 5<SUP>th</SUP> harmonic still remains in the output waveform. Therefore, it is proposed in this paper to ignore solving the equation associated with the highest order harmonics. A reduction in the eliminated harmonics results in an increase in the degrees of freedom. As a result, the lower order harmonics are eliminated in more operating points. A 9-level inverter is chosen as a case study. The genetic algorithm (GA) for optimization purposes is used. Simulation results verify the proposed method.

Therapeutic Outcomes of Pectoralis Major Muscle Turnover Flap in Mediastinitis

Reza Bagheri,Mohammad Abbasi Tashnizi,Seyed Ziaollah Haghi,Maryam Salehi,Ata’ollah Rajabnejad,Mohsen Hatami Ghale Safa,Mohammad Vejdani 대한흉부외과학회 2015 Journal of Chest Surgery (J Chest Surg) Vol.48 No.4

Background: This study aimed to evaluate the therapeutic results and safety of pectoralis major muscle turnover flaps in the treatment of mediastinitis after coronary artery bypass grafting (CABG) procedures. Methods: Data regarding 33 patients with post-CABG deep sternal wound infections (DSWIs) who underwent pectoralis major muscle turnover flap procedures in the Emam Reza and Ghaem Hospitals of Mashhad, Iran were reviewed in this study. For each patient, age, sex, hospital stay duration, remission, recurrence, and associated morbidity and mortality were evaluated. Results: Of the 2,447 CABG procedures that were carried out during the time period encompassed by our study, DSWIs occurred in 61 patients (2.5%). Of these 61 patients, 33 patients (nine females [27.3%] and 24 males [72.7%]) with an average age of 63±4.54 years underwent pectoralis major muscle turnover flap placement. Symptoms of infection mainly occurred within the first 10 days after surgery (mean, 10.24±13.62 days). The most common risk factor for DSWIs was obesity (n=16, 48.4%) followed by diabetes mellitus (n=13, 39.4%). Bilateral and unilateral pectoralis major muscle turnover flaps were performed in 20 patients (60.6%) and 13 patients (39.4%), respectively. Complete remission was achieved in 25 patients (75.7%), with no recurrence in the follow-up period. Four patients (12.1%) needed reoperation. The mean hospitalization time was 11.69±6.516 days. Four patients (12.1%) died during the course of the study: three due to the postoperative complication of respiratory failure and one due to pulmonary thromboembolism. Conclusion: Pectoralis major muscle turnover flaps are an optimal technique in the treatment of post-CABG mediastinitis. In addition to leading to favorable therapeutic results, this flap is associated with minimal morbidity and mortality, as well as a short hospitalization time.

Conversion of biogas from anaerobic digestion to single cell protein and bio-methanol: mechanism, microorganisms and key factors - A review

Reza Salehi,Sumate Chaiprapat 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.4

Biogas is a mixture of mainly CH₄ and CO₂, which can be generated from anaerobic digestion of organic materials. The use of biogas is mostly limited to thermal energy and electricity generation. However, the abundance of cheap shale gas and solar energy could drive out biogas for such applications in the near future. Hence, alternative applications of biogas have recently received great attention among researchers across the globe. This review, for the first time, discusses the feasibility of the bioconversion of biogas to value-added products, including single cell protein as animal feed supplement, and methanol that is an important building block in the chemical industries. Mechanisms of the process, microorgnisms involved and key parameters affecting their efficiency are discussed in detail. Some future research needs are suggested in order to deepen our understanding of these biochemical processes.

Harmonic Elimination and Optimization of Stepped Voltage of Multilevel Inverter by Bacterial Foraging Algorithm

Reza-Salehi,Behrooz-Vahidi,Naeem-Farokhnia,Mehrdad-Abedi 대한전기학회 2010 Journal of Electrical Engineering & Technology Vol.5 No.4

A new family of DC to AC converters, referred to as multilevel inverter, has received much attention from industries and researchers for its high power and voltage applications. One of the conventional techniques for implementing the switching algorithm in these inverters is optimized harmonic stepped waveform (OHSW). However, the major problem in using this technique is eliminating low order harmonics by solving the nonlinear and complex equations. In this paper, a new approach called the "bacterial foraging algorithm" (BFA) is employed. This algorithm eliminates and optimizes the harmonics in a multilevel inverter. This method has higher speed, precision, and convergence power compared with the genetic algorithm (GA), a famous evolutionary algorithm. The proposed technique can be expanded in any number of levels. The purpose of optimization is to remove some low order harmonics, as well as to ensure the fundamental harmonic retained at the desired value. As a case study, a 13-level inverter is chosen. The comparison results by MATLAB software between the two optimization methods (BFA and GA) have shown the effectiveness and superiority of BFA over GA where convergence is desired to achieve global optimum.

Leaf Gas Exchanges and Mineral Ion Composition in Xylem Sap of Iranian Melon Affected by Rootstocks and Training Methods

Salehi, Reza,Kashi, Abdolkarim,Lee, Jung-Myung,Babalar, Mesbah,Delshad, Mojtaba,Lee, Sang-Gyu,Huh, Yun-Chan American Society for Horticultural Science 2010 HortScience Vol.45 No.5

<P>Photosynthetic characteristics, concentrations of mineral elements in xylem sap, and some vegetative traits of ‘Khatooni’ melon were compared with those of melons grafted onto three <I>Cucurbita</I> rootstocks cvs., Ace, Shintozwa, and ShintoHongto, and trained with three methods: T1) no pinching and fruit thinning; T2) pinched to produce two lateral branches; and T3) pinched to two branches and all the flowers and lateral branches from lower nodes thinned. Internal CO2 and water use efficiency varied with rootstocks. Stem diameter of scions, aerial fresh and dry weights, mean fruit weight and yield, electric conductivity, pH, and sap volume per plant of grafted plants were higher in grafted melons than in the nongrafted ones. These traits were unaffected by training methods. Mineral concentrations varied considerably depending on the rootstocks and training methods used. Xylem sap collected from the decapitated stem base of grafted melons trained with T2 and T3 methods contained a higher amount of mineral ions, especially NO3<SUP>−</SUP>, PO4<SUP>3−</SUP>, and K<SUP>+</SUP>, than did the sap from own-rooted plants. The increase in the mineral levels in sap resulting from grafting was most apparent in ‘Khatooni’ grafted onto ‘ShintoHongto’ rootstock.</P>

Effect of Grafting on Survival of Cucumber, Watermelon and Melon Plants Grafted onto Cucurbita spp. Rootstocks by Hole Insertion Grafting

Reza Salehi,Abdolkarim Kashi,Roghayeh Javanpoor 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Assessing the Survival and Growth Performance of Iranian Melon to Grafting onto Cucurbita Rootstocks

Reza Salehi-Mohammadi,Abdolkarim Kashi,Sang Gyu Lee(이상규),Yun Chan Huh(허윤찬),Jung-Myung Lee(이정명),Mesbah Babalar,Mojtaba Delshad 한국원예학회 2009 원예과학기술지 Vol.27 No.1

이란의 대표적인 멜론 품종인 ‘Khatooni’ 멜론을 한국에서 사용하고 있는 신토홍토, 에이스, 신토좌 대목에 접목하여 접목 친화성과 생육특성을 조사하였으며 접목하지 않은 자생묘를 대조구로 두었다. 조사항목은 근활력, 줄기길이, 대목직경, 접수직경, 엽수, 엽록소함량, 엽면적, 생체중과 건물중을 접목후 30과 60일에 조사하였다. 대목별로 97% 이상의 친화성을 보였으며, 신토좌 대목을 제외하고 접수보다 대목의 유관속이 많았다. 근활력은 신토좌 대목에 접목한 처리에서 높았고, 줄기 조절에서는 적심을 하지 않은 처리(T1)에서 높았다. 이 실험 결과, 이란 멜론에서도 한국에서 사용되고 있는 대목을 사용하여 접목재배를 적용할 수 있을 것으로 생각되었다. ‘Khatooni’ melon was grafted onto three Cucurbita rootstocks including interspecific hybrids to examine scion-rootstock compatibility and to correlate plant performance under greenhouse conditions. Commercial cultivars, ‘ShintoHongto’, ‘Ace’, and ‘Shintozwa’, were used as rootstock and non-grafted plants used as controls. Root activity, stem length, rootstock hypocotyl diameter, scion hypocotyl diameter, leaf number, chlorophyll content, leaf area, length and width of leaf, fresh and dry weight of top organs and roots were recorded 30 and 60 days after grafting. The rootstocks showed high compatibility of up to 97% with scions. The rootstocks except ‘Shintozwa’ had more vascular bundles than scion plants. Vegetative growth of the grafted melon plants varied markedly, indicating differences in compatibility between the scion and rootstocks. Significant differences in vegetative growth were found in melons grafted onto rootstocks and trained with different training methods and T1 treatment (non-pinched) had higher values. In the grafted melon, root activity was the highest in the ‘Shintozwa’ rootstock. Grafted melon plants trained with T1 treatment in the second measuring time showed higher root activity than other training methods plants. Among the grafted seedlings, all the rootstocks exhibited similar effects. According to the results, practical use of the tested rootstocks can be advisable for Iranian melon.