388 research outputs found

    Operation and planning of distribution networks with integration of renewable distributed generators considering uncertainties: a review

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    YesDistributed generators (DGs) are a reliable solution to supply economic and reliable electricity to customers. It is the last stage in delivery of electric power which can be defined as an electric power source connected directly to the distribution network or on the customer site. It is necessary to allocate DGs optimally (size, placement and the type) to obtain commercial, technical, environmental and regulatory advantages of power systems. In this context, a comprehensive literature review of uncertainty modeling methods used for modeling uncertain parameters related to renewable DGs as well as methodologies used for the planning and operation of DGs integration into distribution network.This work was supported in part by the SITARA project funded by the British Council and the Department for Business, Innovation and Skills, UK and in part by the University of Bradford, UK under the CCIP grant 66052/000000

    Multi-objective short-term scheduling of a renewable-based microgrid in the presence of tidal resources and storage devices

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    YesDaily increasing use of tidal power generation proves its outstanding features as a renewable source. Due to environmental concerns, tidal current energy which has no greenhouse emission attracted researchers’ attention in the last decade. Additionally, the significant potential of tidal technologies to economically benefit the utility in long-term periods is substantial. Tidal energy can be highly forecasted based on short-time given data and hence it will be a reliable renewable resource which can be fitted into power systems. In this paper, investigations of effects of a practical stream tidal turbine in Lake Saroma in the eastern area of Hokkaido, Japan, allocated in a real microgrid (MG), is considered in order to solve an environmental/economic bi-objective optimization problem. For this purpose, an intelligent evolutionary multi-objective modified bird mating optimizer (MMOBMO) algorithm is proposed. Additionally, a detailed economic model of storage devices is considered in the problem. Results show the efficiency of the suggested algorithm in satisfying economic/environmental objectives. The effectiveness of the proposed approach is validated by making comparison with original BMO and PSO on a practical MG.Iran National Science Foundation; Royal Academy of Engineering Distinguished Visiting Fellowship under Grant DVF1617\6\4

    Power Conditioning of Distribution Networks via Single-Phase Electric Vehicles Equipped

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    A deterministic approach for active distribution networks planning with high penetration of wind and solar power

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    YesIn this paper, a novel deterministic approach for the planning of active distribution networks within a distribution market environment considering multi-configuration of wind turbines (WTs) and photovoltaic (PV) cells is proposed. Multi-configuration multi-period market-based optimal power flow is utilized for maximizing social welfare taking into account uncertainties associated with wind speed, solar irradiance and load demand as well as different operational status of WTs and PVs. Multi-period scenarios method is exploited to model the aforementioned uncertainties. The proposed approach assesses the effect of multiple-configuration of PVs and WTs on the amount of wind and solar power that can be produced, the distribution locational marginal prices all over the network and on the social welfare. The application of the proposed approach is examined on a 30-bus radial distribution network.This work was supported in part by the Royal Academy of Engineering Distinguished Visiting Fellowship Grant DVF1617/6/45 and by the University of Bradford, UK under the CCIP grant 66052/000000

    Psychometrics properties of the Iranian version of fertility quality of life tool: a cross- sectional study

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    Background: Clinical measurement of quality of life for assessing reproductive problems should be considered as a standard investigation at the initial and continuing medical consultations with infertile people. Objective: The purpose of this study was comprehensive testing the psychometric properties of the Iranian version of fertility quality of life (FertiQol) as its use could be considerable due to the prevalence of infertility in Iran and the importance of evaluation of QoL in patients with infertility. Method and material: This was a psychometric properties study of 300 women referred to infertility clinic, Hormozgan, Iran. After linguistic validation of the Iranian version of MPCOSQ, a semi-structured interview was conducted to assess face validity. Consequently exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were performed to indicate the scale constructs. Discriminant validity was assessed using the known groups comparison. Convergent validity was evaluated by assessing the correlation between similar content on the 12-Item Short Form Health Survey, Hospital Anxiety and Depression Scale and FertiQol. In addition, reliability analysis was carried out with internal consistency. Results: The reliability of the Iranian version of the FertiQol questionnaire was satisfactory in all dimensions (Cronbach’s alpha ranging from 0.77 to 0.83 ). Six factors (emotional, mind/body, relational, social, environmental and tolerability) were extracted from the results of EFA with factor loading of the more than 0.3. Discrimination validity showed that FertiQol can differentiate between female patients with differing duration of infertility and number of children; this indicates favorable discrimination validity. Moreover, the results of convergent validity showed a favorable correlation between the related dimensions of 12-Item Short Form Health Survey (correlation ranging from 0.43 to 0.68 ), Hospital Anxiety and Depression Scale(correlation ranging from 0.47 to 0.52 ) and FertiQol. Conclusion: The Iranian version of FertiQol is valid and reliable for assessing infertility problems and the effects of treatment on quality of life of infertile patients referred for diagnosis and treatment at an Iranian infertility clinic. The clinical use of this measure is recommended for Iranian infertility clinics

    Comparative study between wear of uncoated and TiAlN-coated carbide tools in milling of Ti6Al4V

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    As is recognized widely, tool wear is a major problem in the machining of difficult-to-cut titanium alloys. Therefore, it is of significant interest and importance to understand and determine quantitatively and qualitatively tool wear evolution and the underlying wear mechanisms. The main aim of this paper is to investigate and analyse wear, wear mechanisms and surface and chip generation of uncoated and TiAlN-coated carbide tools in a dry milling of Ti6Al4V alloys. The quantitative flank wear and roughness were measured and recorded. Optical and scanning electron microscopy (SEM) observations of the tool cutting edge, machined surface and chips were conducted. The results show that the TiAlN-coated tool exhibits an approximately 44% longer tool life than the uncoated tool at a cutting distance of 16 m. A more regular progressive abrasion between the flank face of the tool and the workpiece is found to be the underlying wear mechanism. The TiAlN-coated tool generates a smooth machined surface with 31% lower roughness than the uncoated tool. As is expected, both tools generate serrated chips. However, the burnt chips with blue color are noticed for the uncoated tool as the cutting continues further. The results are shown to be consistent with observation of other researchers, and further imply that coated tools with appropriate combinations of cutting parameters would be able to increase the tool life in cutting of titanium alloys

    Psychometrics properties of the Iranian version of fertility quality of life tool: a cross- sectional study

    Get PDF
    Background: Clinical measurement of quality of life for assessing reproductive problems should be considered as a standard investigation at the initial and continuing medical consultations with infertile people. Objective: The purpose of this study was comprehensive testing the psychometric properties of the Iranian version of fertility quality of life (FertiQol) as its use could be considerable due to the prevalence of infertility in Iran and the importance of evaluation of QoL in patients with infertility. Method and material: This was a psychometric properties study of 300 women referred to infertility clinic, Hormozgan, Iran. After linguistic validation of the Iranian version of MPCOSQ, a semi-structured interview was conducted to assess face validity. Consequently exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were performed to indicate the scale constructs. Discriminant validity was assessed using the known groups comparison. Convergent validity was evaluated by assessing the correlation between similar content on the 12-Item Short Form Health Survey, Hospital Anxiety and Depression Scale and FertiQol. In addition, reliability analysis was carried out with internal consistency. Results: The reliability of the Iranian version of the FertiQol questionnaire was satisfactory in all dimensions (Cronbach’s alpha ranging from 0.77 to 0.83 ). Six factors (emotional, mind/body, relational, social, environmental and tolerability) were extracted from the results of EFA with factor loading of the more than 0.3. Discrimination validity showed that FertiQol can differentiate between female patients with differing duration of infertility and number of children; this indicates favorable discrimination validity. Moreover, the results of convergent validity showed a favorable correlation between the related dimensions of 12-Item Short Form Health Survey (correlation ranging from 0.43 to 0.68 ), Hospital Anxiety and Depression Scale(correlation ranging from 0.47 to 0.52 ) and FertiQol. Conclusion: The Iranian version of FertiQol is valid and reliable for assessing infertility problems and the effects of treatment on quality of life of infertile patients referred for diagnosis and treatment at an Iranian infertility clinic. The clinical use of this measure is recommended for Iranian infertility clinics
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