28 research outputs found

    Mixed Medullary-Follicular Carcinoma of the Thyroid

    Get PDF
    Mixed medullary-follicular thyroid carcinoma is an uncommon tumor that consists of both follicular and parafollicular cells. Case.We report a 43-year-old woman with a palpable mass in the right side of the neck. Fine needle aspiration suggested a diagnosis of high grade anaplastic carcinoma that has been associated with papillary features. Total thyroidectomy was done in which histopathological examination showed diagnosis of medullary carcinoma. Immunohistochemical staining was positive for chromogranin, calcitonin, and thyroglobulin in tumoral cells. Conclusion. Mixed medullary-follicular thyroid carcinoma is a rare tumor. Diagnosis of these tumors with fine needle aspiration is very difficult and may lead to misdiagnosis. It is necessary to correlate the cytological finding with serum calcitonin and thyroglobulin. Also immunostaining for calcitonin and thyroglobulin confirms diagnosis

    A comprehensive review on brushless doubly-fed reluctance machine

    Get PDF
    The Brushless Doubly-Fed Reluctance Machine (BDFRM) has been widely investigated in numerous research studies since it is brushless and cageless and there is no winding on the rotor of this emerging machine. This feature leads to several advantages for this machine in comparison with its induction counterpart, i.e., Brushless Doubly-Fed Induction Machine (BDFIM). Less maintenance, less power losses, and also more reliability are the major advantages of BDFRM compared to BDFIM. The design complexity of its reluctance rotor, as well as flux patterns for indirect connection between the two windings mounted on the stator including power winding and control winding, have restricted the development of this machine technology. In the literature, there is not a comprehensive review of the research studies related to BDFRM. In this paper, the previous research studies are reviewed from different points of view, such as operation, design, control, transient model, dynamic model, power factor, Maximum Power Point Tracking (MPPT), and losses. It is revealed that the BDFRM is still evolving since the theoretical results have shown that this machine operates efficiently if it is well-designed

    A comprehensive review on brushless doubly-fed reluctance machine

    Get PDF
    © 2021 by the authors. Licensee MDPI, Basel, Switzerland. The Brushless Doubly-Fed Reluctance Machine (BDFRM) has been widely investigated in numerous research studies since it is brushless and cageless and there is no winding on the rotor of this emerging machine. This feature leads to several advantages for this machine in comparison with its induction counterpart, i.e., Brushless Doubly-Fed Induction Machine (BDFIM). Less maintenance, less power losses, and also more reliability are the major advantages of BDFRM compared to BDFIM. The design complexity of its reluctance rotor, as well as flux patterns for indirect connection between the two windings mounted on the stator including power winding and control winding, have restricted the development of this machine technology. In the literature, there is not a comprehensive review of the research studies related to BDFRM. In this paper, the previous research studies are reviewed from different points of view, such as operation, design, control, transient model, dynamic model, power factor, Maximum Power Point Tracking (MPPT), and losses. It is revealed that the BDFRM is still evolving since the theoretical results have shown that this machine operates efficiently if it is well-designed

    Scheduling of Air Conditioning and Thermal Energy Storage Systems Considering Demand Response Programs

    Get PDF
    The high penetration rate of renewable energy sources (RESs) in smart energy systems has both threat and opportunity consequences. On the positive side, it is inevitable that RESs are beneficial with respect to conventional energy resources from the environmental aspects. On the negative side, the RESs are a great source of uncertainty, which will make challenges for the system operators to cope with. To tackle the issues of the negative side, there are several methods to deal with intermittent RESs, such as electrical and thermal energy storage systems (TESSs). In fact, pairing RESs to electrical energy storage systems (ESSs) has favorable economic opportunities for the facility owners and power grid operators (PGO), simultaneously. Moreover, the application of demand-side management approaches, such as demand response programs (DRPs) on flexible loads, specifically thermal loads, is an effective solution through the system operation. To this end, in this work, an air conditioning system (A/C system) with a TESS has been studied as a way of volatility compensation of the wind farm forecast-errors (WFFEs). Additionally, the WFFEs are investigated from multiple visions to assist the dispatch of the storage facilities. The operation design is presented for the A/C systems in both day-ahead and real-time operations based on the specifications of WFFEs. Analyzing the output results, the main aims of the work, in terms of applying DRPs and make-up of WFFEs to the scheduling of A/C system and TESS, will be evaluated. The dispatched cooling and base loads show the superiority of the proposed method, which has a smoother curve compared to the original curve. Further, the WFFEs application has proved and demonstrated a way better function than the other uncertainty management techniques by committing and compensating the forecast errors of cooling loads

    Residual Information of Previous Decision Affects Evidence Accumulation in Current Decision

    Get PDF
    Bias in perceptual decisions can be generally defined as an effect which is controlled by factors other than the decision-relevant information (e.g., perceptual information in a perceptual task, when trials are independent). The literature on decision-making suggests two main hypotheses to account for this kind of bias: internal bias signals are derived from (a) the residual of motor signals generated to report a decision in the past, and (b) the residual of sensory information extracted from the stimulus in the past. Beside these hypotheses, this study suggests that making a decision in the past per se may bias the next decision. We demonstrate the validity of this assumption, first, by performing behavioral experiments based on the two-alternative forced-choice (TAFC) discrimination of motion direction paradigms and, then, we modified the pure drift-diffusion model (DDM) based on the accumulation-to-bound mechanism to account for the sequential effect. In both cases, the trace of the previous trial influences the current decision. Results indicate that the probability of being correct in the current decision increases if it is in line with the previously made decision even in the presence of feedback. Moreover, a modified model that keeps the previous decision information in the starting point of evidence accumulation provides a better fit to the behavioral data. Our findings suggest that the accumulated evidence in the decision-making process after crossing the bound in the previous decision can affect the parameters of information accumulation for the current decision in consecutive trials

    Investigating Impacts of CVR and Demand Response Operations on a Bi-Level Market-Clearing With a Dynamic Nodal Pricing

    Get PDF
    This paper investigates the impacts of conservation voltage reduction (CVR) on electricity prices, the local market, and technical issues in distribution networks. An increase in electricity demand is one of the key challenges for developing sustainable societies. An increase in electric consumption puts immense pressure on electricity providers, which forces them to apply for load reduction programs during peak-demand time intervals. The CVR is one of the popular methods for load reduction, but how it would impact the pricing process and electricity market at the distribution level needs further investigation. The proposed methodology includes a power tracing and loss allocation-based pricing method. Since the distribution networks are going to be confronted by penetration of distributed energy resources (DER), prosumers, and microgrids, it is important to have a comprehensive methodology. This paper deploys a bi-level optimization algorithm to consider the financial benefits of all participating agents. In addition to CVR, the demand response (DR) programs are considered to shift and curtail flexible loads by the distribution system operator (DSO) and prosumers, respectively. The price sensitivity of prosumers toward change in the network’s voltage for better planning is calculated. The operation costs/profits of DSO/prosumers decrease/increase during CVR and DR programs by 4.63% / 3%, respectively.©2023 Authors. Published by IEEE. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/fi=vertaisarvioitu|en=peerReviewed

    Optimal construction of microgrids in a radial distribution system considering system reliability via proposing dominated group search optimization algorithm

    Get PDF
    In contemporary electrical networks, reliability stands as a paramount attribute. Since the introduction of distributed generation (DG) and microgrid (MG) concepts has considerably changed the structure of distribution networks, it is necessary to consider reliability aspects while going toward modern smart grids. This study introduces a novel methodology focusing on the partitioning of radial distribution systems into distinct MGs, strategically aimed at minimizing energy not supplied (ENS) to fortify overall system reliability. Two types of faults are considered including DG and busbar failures, and the impact of each kind of fault is investigated. Besides, a new Markov model is proposed to evaluate the reliability of DGs and MGs. Given the stochastic nature of the majority of DGs, the incorporation of energy storage systems (ESSs) can significantly enhance system performance. Therefore, this paper dedicates attention to exploring optimal ESS placement. To address the complex challenge of optimizing system partitioning, a modified version of the group search optimization (GSO) algorithm, named dominated GSO (DGSO) is proposed. The PG&E 69-bus distribution system is studied with two different structures to accurately investigate the effectiveness of the proposed partitioning approach on the system reliability. Moreover, the optimal number of MGs to be constructed within the intended system is determined
    corecore