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Although inverters with high number of levels offer many merits, their utilization is hindered mainly by their complicated control. Overcoming this barrier gives them the opportunity to find more practical applications. This paper presents an effective closed-loop space-vector-based modulation algorithm to control flying capacitor multilevel inverters with linearly distributed flying capacitor voltages. This modulation technique drastically reduces the computational load. Besides, it is able to balance capacitor voltages more simply and effectively than other methods presented so far. It does not require any stored information from memory or a lookup table. Therefore, it permits online computation of the switching sequence. Moreover, due to the closed-loop structure of this method, the effect of system nonlinearity and capacitor voltage deregulation on performance of the modulation is reduced. Other advantages of the proposed algorithm are: low number of instructions, level-independent number of instructions, and simple extendibility to an arbitrary number of levels without considerable modification. © 2014 IEEE. Source

Bazzazian S.,Islamic Azad University at Abhar | Besharat M.A.,University of Tehran
Psychology, Health and Medicine

The aim of this study was to develop and test a model of adjustment to type I diabetes. Three hundred young adults (172 females and 128 males) with type I diabetes were asked to complete the Adult Attachment Inventory (AAI), the Brief Illness Perception Questionnaire (Brief IPQ), Task-oriented subscale of the Coping Inventory for Stressful Situations (CISS), D-39, and well-being subscale of the Mental Health Inventory (MHI). HbA1c was obtained from laboratory examination. Results from structural equation analysis partly supported the hypothesized model. Secure and avoidant attachment styles were found to have effects on illness perception, ambivalent attachment style did not have significant effect on illness perception. Three attachment styles had significant effect on task-oriented coping strategy. Avoidant attachment had negative direct effect on adjustment too. Regression effects of illness perception and task-oriented coping strategy on adjustment were positive. Therefore, positive illness perception and more usage of task-oriented coping strategy predict better adjustment to diabetes. So, the results confirmed the theoretical bases and empirical evidence of effectiveness of attachment styles in adjustment to chronic disease and can be helpful in devising preventive policies, determining high-risk maladjusted patients, and planning special psychological treatment. © 2012 Copyright Taylor and Francis Group, LLC. Source

Background: This research seeks to measure the attitudes of female students of the Islamic Azad University of Abhar toward family formation and family planning and its influencing factors. Also, efforts have been focused on answering to two major questions: A) Which are the influencing factors on the attitudes of girl students towards marriage and family planning? B) What are the hopes and plans of female students for their future in the context of marriage, employment and education? Objective: In this context, mainly three major hypotheses have been discussed which separately studied the effects of cultural health and demographic and social factors on the attitudes of people towards family organization and planning. The population of the study was included of all students of the Islamic Azad University of Abhar that was studying in this university in academic year of 2009-2010. Results:Since the study population make up the future women of our community and they are at the stage of leaving behind the university and actually have announced their willingness to actively participate in science and society, considering their views, especially with regard to the research topic (their attitudes toward family formation and planning) will help people who are interested in research, study, investigation and planning in such cases. Conclusion: Therefore by using questionnaires the needed data have been gathered and by using SPSS and Path analysis method, the obtained results have been analyzed. The major tips and results that have be obtained we can mentioned the acceptance of family planning programs (Use of contraception, age spacing between births, controlling and limiting the number of children), Planning to form a family and get married with the coherent and organized knowledge and plan (With a gradual tendency of individuals to freedom of thought and yet respect the customs and traditions) and finally, awareness of the consequences of population growth noted in the study population. © 2013 AENSI Publisher All rights reserved. Source

Ghorbani A.,Islamic Azad University at Abhar
Electric Power Systems Research

Distance relays detect transmission line faults and their locations by measuring the voltage and the current signals. Also, phase shifting transformers (PSTs) are used to control the power flow in electrical power systems. PSTs protect transmission lines from thermal overloading, improve the stability of transmission system and control the power flow between different networks. Unfortunately, existence of PST in a transmission line vitiates the operation of protection relays by altering the voltage and current signals. In this paper, the effects of the delta-hexagonal PST on the operation of distance relays are investigated by both analytical and computational methods under different fault types and locations. Results of investigations reveal that the PST causes the distance relays to under-reach. Finally, a feasible method for eliminating the PST detrimental effects on the operation of the distance relays is presented. This method uses the voltage difference between the PST terminals to modify the operation of the distance relays. The phasor measurement units (PMUs) are used to calculate this voltage and remote signal systems are used to transfer it to the system protection center (SPC). All the simulations are conducted with electro-magnetic transient program (EMTPWorks). © 2015 Elsevier B.V. All rights reserved. Source

Hosseini S.A.,Islamic Azad University at Abhar
Annals of Nuclear Energy

The very complex geometry of PBM type reactors along with software limitations have made the simulation of this type of reactor very difficult, even in the case of such flexible code's as MCNP. In this paper a new random distribution method is proposed for the pebbles inside the core. This method has the advantage of needing a limited number of surfaces and cells thus reducing computation time and making it usable in older versions of MCNP. Whilst keeping the geometry as simple as possible, as shown by our simulations, this new distribution method greatly enhances the results obtained in the criticality height benchmark. © 2012 Elsevier Ltd. All rights reserved. Source

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