98 research outputs found

    Economic Self-Operation of Microgrids By Gravitational Emulation Local Search Algorithm

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    Islanded microgrid (MG) is a microgrid which is disconnected from the main network and therefore it is safe and has lead to one of the most important challenges in the power system operation. In the case of higher price in the market, the islanded MG offers a lower operational cost. On the other hand, the nonlinear attribute of optimal operation of the islanded MG has made difficulties in using such systems. To overcome this obstacle, a new heuristic method known as the Gravitational Emulation Local Search Algorithm (GELSA) is proposed in this paper in order to solve the problem. The efficiency of the technique is examined on a modified IEEE 30 bus test network

    Region Search Optimization Algorithm for Economic Energy Management of Grid-Connected Mode Microgrid

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    Economic energy management of grid-connected microgrid has been widely investigated. However, due to the binary variables of the generation unit’s status, the optimal result of the grid-connected microgrid is very hard. Thus, in this paper, the region search optimization algorithm (RSOA) is developed and adopted for the energy management of the grid-connected microgrid. The developed technique has higher convergence speed and accuracy, compared to the well-known heuristic techniques, such as genetic algorithm and particle swarm optimization. Results shows the effectiveness of the developed model

    Economic Self-Operation of Microgrids By Gravitational Emulation Local Search Algorithm

    Get PDF
    Islanded microgrid (MG) is a microgrid which is disconnected from the main network and therefore it is safe and has lead to one of the most important challenges in the power system operation. In the case of higher price in the market, the islanded MG offers a lower operational cost. On the other hand, the nonlinear attribute of optimal operation of the islanded MG has made difficulties in using such systems. To overcome this obstacle, a new heuristic method known as the Gravitational Emulation Local Search Algorithm (GELSA) is proposed in this paper in order to solve the problem. The efficiency of the technique is examined on a modified IEEE 30 bus test network

    Economic Operation of Islanded Microgrids Based on the Region Search Evolutionary Algorithm

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    In this paper a new evolutionary algorithm based on the region search evolutionary algorithm (RSEA) is developed for optimal energy management and operation of microgrids. Islanded microgrid operation is more crucial than the conventional distribution grids because of less dependency of the extremal (upstream) generation units. Thus, an effective economic operation of islanded microgrid need a strong algorithm to meet all constraint associated with the problem. The proposed developed RSEA technique is tested on the IEEE 33 bus test system. Results show the effectiveness of the RSEA technique, compared to the well-known evolutionary techniques

    Application of Fractal Analysis in Detecting Trabecular Bone Changes in Periapical Radiograph of Patients with Periodontitis

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    Evaluation of detailed features of the supporting bone is an important step in diagnosis and treatment planning for teeth with clinical attachment loss. Fractal analysis can be used as a method for evaluating the complexity of trabecular bone structures. The aim of this study was to evaluate the trabecular bone changes in periapical radiographs of patients with different stages of periodontitis using fractal analysis. Methods. This comparative cross-sectional study was performed on patients with and without clinical attachment loss in mandibular first molars. Teeth with clinical attachment loss were divided into mild, moderate, and severe periodontitis groups. Digital periapical radiographs were obtained from the mandibular first molars using the same exposure parameters. DICOM file of the radiographs was exported to ImageJ software for fractal analysis. Three regions of interest (ROIs) were considered in each radiograph: two proximal ROIs mesial and distal to the mandibular first molar and one apical ROI. Fractal dimension (FD) values were calculated using the fractal box counting approach. Statistical analysis was performed using the chi-square test, Mann–Whitney test, intraclass correlation coefficient, and ANOVA (α = 0.05). Results. FD values were significantly different between moderate and severe periodontitis and healthy periodontal bone (P0.05). Conclusion. Fractal analysis is a useful tool for evaluation of bone alterations in moderate and severe periodontitis, but was not able to detect the most initial radiographic bone signs of mild periodontitis

    Topical Tacrolimus as an adjunct to Conventional Therapy for Stromal Herpetic Keratitis: a Randomized Clinical Trial

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    Purpose: This study investigates the effects of 0.05% topical tacrolimus as an adjunct therapy for patients with non-necrotizing herpetic stromal keratitis (HSK). Methods: Patients with non-necrotizing HSK, referred to the Cornea Clinic at Hospital in Rasht, Iran, between September 2016 and February 2018, were randomly assigned to two groups. The case group (N = 25) and the control group (N = 25) received conventional treatment with systemic acyclovir and topical prednisolone. The case group (N = 25) additionally received 0.05% tacrolimus eye drops four times a day for one month. Complete ocular examinations, including best-corrected visual acuity (BCVA) assessment, intraocular pressure (IOP) measurement, slit lamp biomicroscopy, and photo slit lamp imaging, were performed before treatment, and 3, 7, 14, 21, and 28 days after the intervention. Results: The mean age of the patients was 46.2 ± 12.9 years, and 70% of the patients were male. There was no difference between the groups in terms of age, sex, and baseline ocular measurements (P > 0.05). The case group had a lower mean logarithm of the minimum angle of resolution (LogMAR) for BCVA, lower grading scores, and steeper decreasing trends for corneal haziness, edema, neovascularization, and epitheliopathy compared to the control group after the second week (P < 0.05), while IOP remained unchanged between groups (P > 0.05). Conclusion: The addition of 0.05% topical tacrolimus enhances visual acuity and reduces corneal inflammation, neovascularization, and scarring; thus, it can used as an appropriate adjunct treatment for patients with HSK

    Synthesis, characterization and performance evaluation of three-layered photoanodes by introducing a blend of WO3 and Fe2O3 for dye degradation

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    A three-layered photoanode has been synthesized by the introduction of an additional layer of mixed WO3 and Fe2O3. A total of nine differently-packaged films were prepared by sol-gel method. The fabricated photoanodes were then successfully characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). A comparative study was also done to differentiate the films fabricated with WO3, Fe2O3 and their mixture. Compact, columnar tree and shallow patterns were observed on the cross cleavage of the synthesized layers. These distinct patterns were associated with the growth of layers which consequently led to unique surface morphologies. An increase in photocurrent density was observed on the bicomponent film which has been linked to a high degree of surface roughness as well as improved internal porosity. Three-layered photoanodes, modified with an additional bicomponent layer of WO3:Fe2O3 established much higher photocurrent outputs compared to that of nanostructured WO3 or Fe2O3, regardless of the bicomponent layer arrangement. However, with the bicomponent layer on top and middle, the measured photocurrent soared more than three times as much compared to a slight increase observed when the bicomponent was placed on the bottom

    The expression analysis of Fra-1 gene and IL-11 protein in Iranian patients with ulcerative colitis

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    Abstract Background: Fra-1 (fosl1) belongs to the activator protein1 (AP-1) family inducing IL-11 expression in oxidative stress condition. IL-11 plays a pivotal role in protecting epithelial barriers integrity. In this study, we investigated the Fra-1 gene expression in the inflamed mucosa of patients with ulcerative colitis (UC) as well as its relation to IL-11 expression. Materials and methods: We enrolled 20 patients and 20 healthy controls with definite UC based on the clinical criteria. Fra-1 gene expression in inflamed and non-inflamed colonic biopsies was determined by real-time polymerase chain reaction (RT-PCR). The IL-11 protein concentration was measured by Enzyme-Linked Immunosorbent Assay (ELISA) method. Pearson correlation was applied to calculate the relation between Fra-1 and IL-11. Results: An increased level of Fra-1 gene expression was observed in patients with mild ulcerative colitis. The protein concentration of IL-11 was also increased in mild UC patients. Conversely, a significant decrease of IL-11 protein level was detected in severe UC patients compared to control group. Conclusion: Oxidative stress in inflamed intestinal biopsies can induce fra-1 gene expression. Our findings suggest that Fra-1 transcription factor leads to the production of IL-11 protein in UC patients
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