Showing 155 results for Rahmat
Volume 1, Issue 1 (3-2013)
Abstract
Aims: Evaluation of Patient Satisfaction (PS) is one of the most essential factors in improving the quality of healthcare systems. The aim of this study is to determine the norms and to evaluate the validity and reliability of the Najmiyeh Outpatients Satisfaction Questionnaire (NOSQ). Methods and Materials: This study has been conducted on 240 outpatients in Najmiyeh subspecialty hospital (Tehran-Iran) in 2011. They were selected using the proportional simple random sampling method. Following the confirmation of the content validity, we considered the construct validity and reliability applying Confirmatory Factor Analysis (CFA) and Explanatory Factor Analysis (EFA) and Cronbach's Alpha. Also, SPSS and AMOS version 18 were used for data analysis. Findings: The sample population consisted of 240 subjects, including 132 females (55.1%) and 108 males (44.9%). The EFA reported three important factors in this regard, with a variance of 54% and Kaiser-Meyer-Olkin index of 0.82, all approved by the CFA (RMSEA= 0.04, CFI= 0.96). The outpatients' satisfaction factors were: “hospital information system, treatment and conditions”. The reliability of the questionnaire was reported at %71 based on the Cronbach's alpha. Conclusions: Both validity and the reliability indexes of the NOSQ have been reported at a desirable level; therefore it can be used as a valid and reliable instrument to measure the outpatients' satisfaction.
Volume 1, Issue 2 (NO. 2- 2009)
Abstract
Keywords: Revolutionary Situation, Power-oriented explanation, General pattern, Theoretical perspectives, Types of explanation .
In this Article, in order to offer a pattern of political (power-oriented) explanation of revolutions, after clarifying its central concept- namely "revolutionary situation"- through cross-cutting of three main theoretical standpoints and two principal types of explanations, we attempted to introduce six important explanation perspectives of such explanations. Then, after remarking the three levels of analysis, we separately introduced the main variables of each explanation. Finally, we mapped their schema in detail and synoptically.
Volume 1, Issue 2 ((Articles in Persian) 2010)
Abstract
Volume 1, Issue 2 (6-2013)
Abstract
Aim: Patients' satisfaction (PS) is a dominant concept in medical care, due to the gap in the literature on Persian version of PS instruments, this study has conducted with aim to analyze the validity and reliability of self-designed Najmiyeh Inpatient Satisfaction Questionnaire (NISQ). Methods: This study was carried out on 247 inpatients that came in Najmiyeh subspecialty hospital in Tehran (the capital city of Iran) during year 2011 who were selected by proportional stratified sampling method. Statistical analysis used: In this study, after checking content validity we used confirmatory and explanatory factor analysis and Cronbach's Alpha in order to examine construct validity and reliability, respectively. SPSS (version18) and AMOS (version 20) programmer were used to analyze data. Findings: Samples consisted of 247 subjects (222 women (90%) and 25 men (10%)). The explanatory factor analysis showed 5 factors with 64% total variance and 0.91 Kaser-Meyer-Olkin Index, the result also confirmed with confirmatory factor analysis (PNFI=0.71, RMR=0.03, PCFI=0.76). Extracted factors consisted of: “satisfaction from nursing services and their behaviour”, “satisfaction from one’s doctor”, “satisfaction from inpatient department”, “companions’ satisfaction”, “satisfaction from one’s room”. Also the questionnaire’s reliability was 0.96 using the Cronbach's Alpha method. Conclusions: Because validity and reliability indexes of NISQ were reported in suitable range, we can confirm that this questionnaire is a valid and reliable tool for measuring inpatient satisfaction.
Volume 1, Issue 3 (10-2014)
Abstract
Background: Age-related differences in the ethoxyresorufin O-deethylase (EROD) activity of CYP1A1 and its inducibility in rats may determine the toxic potential of acetaminophen. This study was carried out to compare the effects of acetaminophen (APAP) and β-naphthoflavone (βNF) on CYP1A1 activity in young and adult rats.
Methods: For this purpose, young and adult rats (n = four / group) were treated with different doses of APAP. Likewise groups of young and adult rats were treated with a single dose of β-naphthoflavone (βNF, 67 mg / kg b.w). EROD was measured in microsomal fraction using resorufin as the substrate.
Results:The results showed that a single i. p. injection of APAP (25 mg / kg B.W.) failed to alter liver microsomal EROD in young and adults. Whereas, in adults treated with 250 and 450 mg APAP / kg B.W, liver CYP1A1 was elevated to about 45 and 60% respectively. The rate of CYP1A1 induction in young rats with single dose of APAP (450 mg/kg B.W) was approximately 32%. Induction in CYP1A1 was noticed 4 h after APAP injection and returned to normal levels in 24 h. The inducibility of CYP1A1 in rats treated with a toxic dose of APAP was comparable to the data obtained from animals treated βNF, 67 mg / kg b.w.
Conclusion: These results together with our previous reports indicate a similar pattern of changes in CYP1A1 in both the age-groups treated with toxic doses of APAP may suggest that the inducible CYP1A1 can equally contribute to protection against liver damage in young and adult rats.
Volume 2, Issue 1 (1-2016)
Abstract
Background: Fusobacterium necrophorum as a non-spore-forming Gram-negative anaerobic bacillus is an important human and animal pathogen. It may cause severe systemic infections (Lemierre's syndrome) and some other infections. The aim of this study was to subtype Fusobacterium necrophorum by using PCR methods. Materials and Methods: Twenty five strains of Fusobacterium necrophorum subspecies funduliformis were used. Extraction of DNA and typing of the strains using REP-PCR, ERIC-PCR and BOX-PCR were done. Results: Molecular typing of Fusobacterium necrophorum using REP1-R-I and REP-2-I primers generated 2 to 5 amplicons ranging in size from 1500bp to 2000bp. GelCompar comparison of banding patterns revealed seven distinct ribotype strains from 25 strains tested of which most were 2 and 4 with 8 and 7 strains respectively. BOX-PCR subtyping generated 2 to 7 comparable amplicons ranging in size from approximately 600bp to more than 2000bp. ERIC-PCR subtyping generated 6 to 11 amplicons ranging in size from approximately 100bp to 1500bp. Conclusions: F. necrophorum strains have genomic variations that suggest they are never truly clonal in nature, or they may have undergone localized genetic variation across worldwide. This study also showed subtypes existing in Fusobacterium necrophorum species. We have demonstrated that Fusobacterium necrophorum REP-PCR types can be divided into seven, three subtypes by BOX-PCR and six subtypes by ERIC-PCR. BOX-PCR typing proved to be the most discriminatory method, yielding two-seven major bands. The sample size was too small to interpret statistically.
Volume 2, Issue 3 ((Articles in Persian) 2011)
Abstract
The main purpose of this study was to determine the degree of using cognitive learning and strategies of learning by Iranian French Language Learners. Furthermore, it aimed at determining the effect of using cognitive strategies on learner autonomy. In doing so, a questionnaire of 12 questions was filled in by 38 post-graduate students of TMU. The frequency of utilization of cognitive strategies including summarizing, memorizing, guessing the meaning of words, repetition, extra-curricular practicing, learning through comparative reasoning, note taking, using mnemo techniques, paraphrasing, review and research is studied. The results of Freidman test showed that the difference between the mean ranks was significant, and the most frequent strategies were note-taking (76.3%), guessing the meaning (75.65%), and elaboration (71.71%). In general, the results showed that among the cognitive strategies, there was almost a correlation between documentary research and extra-curricular activities. There was also a positive correlation with autonomy(58%).
Volume 2, Issue 3 (12-2013)
Abstract
The gill Structure and localization of Na+, K+-ATPase were examined through branchial arches of the Persian sturgeon, Acipenser persicus larvae (25 days-post-hatched, 417.3 mg). Studies were conducted through light microscopy (H&E Staining) and immunofluorescence for Na+, K+-ATPase. Results showed each gill consisted of four complete holobranches and opercular hemibranch. Each filament carried rows of lamellae consisting of a network of interconnecting blood lacunae, which were lined by pillar cell flanges. Pavement cells covered the outermost layer of the lamella and blood cells were found in lacunae. High density of ionocytes (529.73 per mm2 of the gill tissue) was found at the base of the lamella, in the interlamellar regions, on the filaments and the septums. Ionocytes possessed large size and round basal nuclei. Ionocytes possessed strong immunofleurescence in their cytoplasm, especially in the basolateral sides because of high concentration of the enzyme. The results showed that the main structures of the gill has already been formed at this developmental stage of the Persian sturgeon, and along with its respiratory and excretory roles, it also plays an important role in osmoregulation.
Volume 3, Issue 1 (1-2017)
Abstract
Background: Gram-negative organisms producing Extended-spectrum beta-lactamases (ESBLs) are presented as a global problem. Klebsiella pneumoniae is considered as one of the most important microorganism of this group. The prevalence rate of K. pneumoniae species is increasing, and this increase is higher in the ESBL group, indicating the increase in antibiotic resistance. We must have sufficient knowledge about regional antibiotics resistance in order to monitor the prevalence rate and antimicrobial resistance among the isolates by appropriate treatment. In this regard, the objective of our study was to evaluate antimicrobial susceptibility among K. pneumoniae isolates by E-test method in Khatam ol Anbia hospital during 2015.
Materials and methods: This descriptive cross-sectional study was carried out during 2015. All clinical samples were collected from intensive care unit (ICU) and general wards of Khatam ol Anbia hospital. All of the K. pneumoniae strains were detected by biochemical and microscopic tests. Antimicrobial susceptibility and minimum inhibitory concentration (MIC) were determined by disk diffusion and E-test methods. Descriptive statistics was used to analyze data.
Results: About 62 K. pneumoniae strains were isolated from clinical samples of ICU and general wards during one year. Of these, 38 (61.3%) isolates were isolated from intensive care unit, and 24 (38.7%) isolates were isolated from the general wards. In this review, the least resistance was related to colistin (4.8%) and Amikacin (14.5%), respectively, and the most resistance was observed to the antibiotics of ciprofloxacin (66.1%), ceftriaxone (62.9%) and gentamicin (59.7%), respectively. Resistance to imipenem was observed in 38.7% of the isolates.
Conclusion: The current study demonstrates that antibiotic resistance pattern is changing, and resistance to imipenem and colistin is rising, so this should be considered as a serious risk for admitted patients in hospital.
Volume 4, Issue 2 (No.2 (Tome 14), (Articles in Persian) 2013)
Abstract
Learning a foreign language, like other fields, undergoes forgetting. Paying attention to forgetting in foreign language writing and speaking abilities is more important since these two realms indicate the learner's competence and performance. This study aimed to investigate the phenomenon of forgetting of Iranian Language learners (French) at the level of language production. To achieve this objective, descriptive and analytical methods were used for reviewing the related theories of forgetting, memory and data storage. In the field study, forgetting of concrete and abstract words between two sexes and two age groups (25-30, 31- 40) was measured by two different tests. According to the results, forgetting depends on the type of words. On this basis, abstract words are more frequently forgotten. The obtained data demonstrated that age and sex have a significant impact on forgetting words. More precisely, these factors affect forgetting, when words appear in a context. So in the age group of 25-30 years, forgetting of abstract words is significant among men and 1.82% more in comparison with women. While in the age group of 31- 40 years, the forgetting degree of women is 2.5% more.
Volume 4, Issue 3 (9-2015)
Abstract
A faunestic study on Stigmaeidae and Cryptognathidae families in Lorestan province was carried out during 2012-2013. In this study 18 species were collected and identified, of which Favognathus amygdalus and F. cordylus (Cryptognathidae) were new records for Iranian fauna, also all of the collected species in this study were new records for fauna of Lorestan province. Stigmaeidae with 14 species and Cryptognatidae with four species had the highest and lowest number of identified species, respectively.
Volume 5, Issue 1 (3-2017)
Abstract
Aim: Every year, a huge number of incidents of irreparable damage to personnel and industries occur, most of which are predictable with identifying hazards as well as risk assessment and control. Therefore, in order to prevent occupational accidents, the automotive industry is one of the top priorities for evaluating and identifying the hazards.
Methods: The purpose of this study is to identify, control and rank the hazards of actions and processes in the hazardous automotive industry. This descriptive-analytical study was carried out in 2017 in one unit of Iran Khodro Company by using FMEA method. Also to accurately assess the health risks and make decisions for corrective actions to prioritize hazard risks, Wiliam Fine and AHP (Analytical Hierarchy Process) methods were used, respectively.
Findings: In this research, a list of 301 risks in 7 units including cutting line, assembly line, prototyping and modification, manufacturing, packaging, quality control, laboratory, and repair and maintenance were provided. The results of FMEA method indicated that the highest risk priority number (RPN) is related to the risks of particle swirling in grinding operations (336). Moreover, based on the results of William Fine method, the exposure to noise in the Kissing & Wessich Sersim Strandbauft operation was rated at 540 and 500, respectively, with the highest risk of evaluation. The risk of exposure to noise (Kicking operation) with a relative weight of 0/1904 was ranked the first.
Conclusion: The results of the hazard analysis showed that the effect of noise pollution that leads to hearing impairment in the staff is very high.
Volume 5, Issue 4 (12-2001)
Abstract
Ali A Rahmatian
Ph.D. Graduate Faculty, Criminal Justic Program Florida Metropolitan University
The purpose of this paper is to describe domestic violence which is a widespread problem affecting families, law enforcement agencies, and the court system Studies investigating the effects of arrests on recidivism in domestic violence cases have led to the implementation of pro-arrest policies in many police agencies. The changing policies have lead to an increase in the number ol domestic violence cases in the court system with limited prosecution of these cases. Police training in the specific dynamics of domestic violence is believed to provide officers with skills necessary in handling these calls safely and accurately, The Lakeland Police Department has developed a comprehensive community project, the Domestic Abuse Response Team (DART), that is designed to reduce the recidivism of domestic violence .in order to serve the victims more efficiently. Examination of components of this program may help to target specific aspects of the training that are useful in reducing recidivism rates, Specific attention is paid to concepts, theories, and models that support the findings that batterers and victims are reacting in a manner they have learned through their family environment and as part of a pattern or cycle of violence in which the abuse is expressed.
Volume 5, Issue 5 (No.5 (Tome 21), (Articles in Persian) 2014)
Abstract
Entering into the Arabic language and literature in the early Islamic centuries, Iranian culture generally turned to become a position of Arabic culture and common among the people in the 4th century (A.H.). This culture has been transferred though the language tool; therefore, it has influenced on the Iranian authors who used to write in Arabic. Abu-Hahyyan Al-Tawhidi is one of the greatest scientists in the Islamic world in the 4th century (A.D.) whose works have Iranian vein. In his book, Titled Al-Amtaa Wal-Muanassa, there are almost100 pension load words, among which 20 words, have appeared for the first time in his work, 21 words have been taken from the Ignorance Age introduced into the Arabic language, and 57 words are loan words borrowed from the Islamic and Arabic eras. The Persian loan words mainly include the names of food stuff, birds, animals, and mechanic herbs. The names of flowers, musical instruments, plays, building tools, etc. have rarely been used in this books. Since, the Persian loanwords are meaningful by themselves; hence, the goal of this study is to assign the cultural meaning/concept of Persian words, which have conveyed in to Arabic Language. As such, through knowing the Semitics of words, the kind of influencing culture can be easily specified.
Volume 6, Issue 2 (11-2015)
Abstract
Firefly luciferase is a light generating enzyme, which is used in different fields of biotechnology and molecular biology. Luciferase has found widespread applications in many areas of genetic analysis such as detecting gene expression, reporter gene assay and proteomics studies such as protein-protein interactions. Despite many advantages, there are some limitations in luciferase-based systems, the most important of which is its low stability. One of the newly developed methods to solve this problem is to take advantage of Deep Eutectic Solvents (DES). One group of DESs is those that composed of organic salts with hydrogen donor, due to which, intermolecular hydrogen bonds cause lower melting point in comparison with each of the component. In this study, we investigated the effects of DES on kinetic properties of wild type and I232R - E354R/Arg356 mutant Lampyris turkestanicus luciferases. For this, both enzymes, wild type and mutant, expressed in BL21, the protein of interest purified through affinity chromatography and used for kinetic studies. Here, we used choline chloride: glycerol as DES. According to the results, the wild type luciferase is much more thermostable in DES than I232R - E354R/Arg356 mutant. Furthermore, the remaining activity of both wild type and mutant luciferases are greater in the presence of DES than those in the absence of DES.
Volume 6, Issue 2 (9-2016)
Abstract
This article is an attempted to redesign of communal and private spaces in public apartments to enhancing social health with the case study of Baharestan 2 complex of Sanandaj city. The Baharestan complex is a public apartment which is built by governmental organizations. The complex is placed on southern part of the city and in a half-old and half-modern context. This residential complex construction process has begun in 2007 by Bonyad-Maskan (Housing Institute) organization and now all constructions are done. Studies indicates that most of residents are dissatisfied from limited spaces, ignoring cultural and social contrast which result in low congruence and convergence of collective and private spaces. In the first look, uniformity of buildings and similarity of blocks over the complex will result visual confusion and reduces sense of place in residents. Also residents complained about some collective, semi collective and private spaces like lobby, waiting hall, corridors and interior plan. This kind of construction reduces value of home in to building which result in increasing soulless spaces. Thus problems of Baharestan 2 complex can be consider as Social health issues. Hence, the relative reduction of problems and subsequently enhancing residents Social-environment statues with architectural design approach is the main purpose of this study. Housing as a place of residence and mental comfort, is one of the human basic needs. Bachelard defines home as internal space regarding external spaces like cities, streets, farms, seas, nature and even universe; a place for fostering dreams. At other hand, Heidegger thinks basic crisis of home is not lack of construction, but is human desire to residence. Schultz defines residence as establishment of a deep relationship between human and surrounded environment. This relationship is an attempt to granting identity and sense of place to a place and emphasizes that human would consolidate if he finds his home. Rappaport believes that home is consist of several parameters but social and cultural aspects are the most important. At other hand WHO defines “Health” as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity”. The Definition has not been amended since 1948. Also in 1986 WHO said that “a resource for everyday life, not the objective of living. Health is a positive concept emphasizing social and personal resources, as well as physical capacities.” In this definition, each member of a family is a member of society and welfare of a member is connected to welfare and health of others. In a residential complex underlying motivations as social stability, reduce conflict and social problems, strengthening social stimuli or perhaps local support is of particular importance. According to Mead (1973) there are several factors which makes a residential complex in to a desired one. These factors are: Compatible neighbors, sense of community and a sense of continuity, knowledge of the biosphere and sense of common destiny. Also diversity, avoiding social-separation, social integration, coexistence, sharing values, lack of social stress, lack of inhibition to develop links with local citizens, ownership, encourage collaboration, safety, security and trust, protection of accidents, theft and vandalism , feedback, participation, effectiveness in decisionmaking, planning and open decision-making, active control mechanisms and appropriate services, are other included factors. Whereas social environment should be compatible with community values. It means that social environment should encourage individual to control and monitor, not to pushing stress on them and deprived them of necessary drivers. Lynch believes human should be able to see well and hear well and interact with others in the community. Elements and components such as the environment, hallway, door, stairs and slopes must comply with individual and social needs of residents. According to Levine, social health is to answer to this fundamental question that whether it be natural method (peaceful or compatible) and acceptable to continue to live with others. Also a method presented to define social health in physical environment design. As social integration concept three subject defined: Social facilitation (social initiation, observability, convergence and accommodation) regarding to intermediary space like corridor, hall and entrance space, social participation (Possibility of choice, productive participation) regarding to personal space like housing unit and social mingling in relation with local community assumed as apartment building. With this background, this paper is dealing with serious problems in residential plans, and specially focused on redesigning collective and semi collective spaces like lobby, waiting hall and corridors, and also possible considerations applied in private plans. This article is a resaerch with survey method. For selecting the respondent›s imporbable sampling method was used. Research has been consist of visionary part (articles, books, specialty Journals, consulting with professors and experts), and operational (analyzing architectural palns, documents, questionaries, workshops with some residents, providing photos and Maping). Workshops with public notification and the presence of a number of heads of household and board of directors in buildings held three sessions. In addition existing and corrective plans evaluated by thirty resident with simple random sampling method. The main assumption was that the proposed plans was to reduce the costs of interventions so that no financial pressure felt by residents and also increases amount of community participation. The questionnaire includes four existing and proposed plans and results in the form of bar graphs extracted and presented in each section. Also data has been analysed with SPSS17.0. Statstical software. Proposed plans defined and designed according to workshops and data obtained from survey research. Quaternaries results indicated that 85 percent of residents are not satisfied with existing plans and about 74 percent are satisfied with proposed plan of lobby. 73 percent of residents are not satisfied with existing plans and about 50 percent are satisfied with proposed plan waiting hall. 70 percent of residents are not satisfied with existing plans and about 74 percent are satisfied with proposed plan corridors. 67 percent of residents are not satisfied with existing plans and about 70 percent are satisfied with proposed interior plan. All in all results indicated that resident are not satisfied with collective, semi collective and private spaces. After accurate explaining of problems and issues, by two-dimension plans, various options presented and after analyzing and discussions and also holding numerous specialty meetings with some residents, final option was chosen and finally plans in details was designed. Main hypothesis of the study was reduction of interventions Costs, to minimizing financial pressure on resident sand increases community participation of residents. Results of the paper has a good agreement with previous studies in this field like Newman (1974), Beer and Higgins (2011), Lynch (2010), Greenbie (1974), and Cooper and Sarkissian (1986), as presented in discussion. All in all, the article as a result emphasizes on requisite of healthy, design, pleasant and sustainable, Particular attention to the needs, desires, and social patterns of the residents general population as main owners of building. There is no doubt that alongside this issue, a lot of mental, social, economic factors have roles in how people behave towards the environment, thus planners and designers should consider appropriate manners.
Volume 7, Issue 1 (5-2015)
Abstract
Cultural area is a geographical area in which an approximately large of group with shared cultural characteristics are present. In the Islamic period, Nishabur city (the remains of which are located in the South East of the modern city of Nishabur), Balkh, Merv and Heart were the four quarters of Great Khorasan in the early centuries until the Mongol invasion, from which only Nishabur in Iran has remained. Based on the historical and geographical sources of the early and middle centuries of the Islamic period, Nishabur has had a broad cultural context, including twelve provinces, a dozen quarters, as well as several towns and villages. Buzhgan, as one of the easternmost twelve provinces of Nishabur, is located within Nilabad Plain, 17 km southeast of Torbatejam, and has been the result of interaction between climatic conditions and political, economic and social relations as in close association with the capital city of Nishabur in the first to seventh centuryies (AH). In this paper, the literature on Buzhgan has been dealt with using a historical analysis approach. The evaluation of written sources indicates the distinct political, economic and cultural role of Nishabur as the most important eastern province in the road from Nishabur to Heart.
Volume 7, Issue 2 (Spring 2019)
Abstract
Aims: Since communication problems between caregivers and the elderly cause reduction and deficiency in caring and issues such as ignoring elderly people and negligence in caring by the caregivers, therefore, this study aimed at evaluating the interpersonal communication skills of elderlies and their caregivers in Khorzugh, Isfahan province.
Materials & Methods: In this descriptive-analytical research, 140 elderly people in Khorzugh were selected by as a target community. Data collection tools were demographic information questionnaire and Queendam's communication skills questionnaire. Spss16 software, Kolmogorov-Smirnov test, Chi-square tests, and Spearman correlation were used for data analysis.
Findings: The mean and standard deviation of elderly people and their caregivers were 66.39±6.16 and 55.0+6.38, respectively. Average score of communication skills of caregivers and elderly from 170 scores was 75.83±11.79 and 90.37±3.81, respectively. The communication skills showed a significant statistical relationship with the age caregivers group and age and occupation in the elderly group (p<0.05). Also, in the elderlies, there was a significant statistical relationship between attitude toward communication with marriage status, listening with living , and emotion control with of children (p<0.05).
Conclusion: According to the results of this study, the level of communication skills of caregivers and most of the elderly was moderate regarding the importance of these skills in establishing effective communication between caregivers and the elderly. The necessity of creating appropriate conditions is felt for improving these skills and it is better to conduct educational programs to enhance the communication skills of the elderly and their caregivers.
Volume 8, Issue 1 (0-2008)
Abstract
Electric arc furnaces (EAFs) are unbalanced, nonlinear and time varying loads, which can cause many problems in the power system quality. In steel industries, the two arc furnaces often perform in parallel and stand on a single bus, which surely deteriorate the power quality. In this paper, in order to study and analyze the harmful effects of parallel operation of EAFs, first, a three phase arc furnace model, which can simulate all the operational conditions of EAFs are simulated based on Hyperbolic-Exponential Model. In this process, in order to perform exact analysis of EAFs, effects of arc furnace transformer and the mutual inductance of the flexible cables are also considered. In the next step, in order to improve the power quality indices, the TSC and TCR/FC compensators are designed optimally and then simulated. Finally, the simulation results that are accomplished by PSCAD/EMTDC software show the validity of the proposed method in the entire power systems.
Volume 8, Issue 1 (0-2008)
Abstract
Induction heating is widely used in metal industry for melting or heating thin slabs in a continuous casting plant. The wide application is based on good efficiency, high production rate and non-polluting conditions. For designing a parallel resonant induction heating system, calculating the capacitance for the resonant circuit is important, because its value affects resonance frequency, output power, power quality factor, heating efficiency and power factor.
In this paper, phase controlled rectifier and H-bridge inverter are modeled. Then a method of finding an optimal value for the capacitance under voltage constraint is presented. This value is selected for maximizing output power of an induction heater, while minimizing the power loss of capacitor at the same time. For this purpose, the role of equivalent series resistance in the choice of capacitance value is significantly recognized. In this regard, the heating coil and the load of induction heating are modeled at first, and then the optimal value of capacitance is selected. Finally a complete model of heater and its power is simulated and effectiveness of the proposed method is verified.