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A Maintenance Optimzation Policy for an Electric Power Distribution System: Case of the HV/MV Substations

Engineering（科研） 2014年第5期6卷 236-253页

作者： morad mahmoudi Abdellah El Barkany Ahmed El Khalfi Department of Mechanical Engineering Faculty of Science and Technology Sidi Mohamed Ben Abdellah University Fez Morocco National Office of Electricity and Water Supply (ONEE) Casablanca Morocco

Today, in the modern era, and under the pressure of rapid development around the kingdom regions, electric utilities are confronted with a myriad of challenges that include aging infrastructure, enhanced expectation of reliability, reduced cost, and coping effectively with uncertainties and changing regulation requirements. Indeed, for distribution systems, HV/MV substations represent a complex and critical physical asset that requires a careful evaluation of their maintenance practices aiming at more cost-effective tasks. The first concern of the electric power distribution company in Morocco is the optimization of the distribution network maintenance scheduling, to minimize system operating costs and ensure that the system is running most economically. There is significant pressure on power providers for greater system reliability and improvement of customer satisfaction, while similar emphasis is placed on cost reduction. These cost reductions focus on reducing operating and maintenance expenses, and minimizing investments in new plants and equipment. However, the present of the electricity distribution, influenced by a number of technical restrictions and strict regulatory requirements to meet, leads distribution utilities to search new ways of optimizing the maintenance management, make an effort to maximize profit by reducing their electricity supply and operation costs while maintaining their reliability, developing more effective activities, with lower costs. Furthermore, maximal HV/MV substation asset value and minimal maintenance cost are typical economic objectives of the electric utilities. The optimization of maintenance is one possible technique to reduce maintenance costs while improving reliability and utilities need to implement new strategies for more effective maintenance techniques and Asset Management (AM) methods programs to manage inspections and maintenance activities in order to control HV/MV substation equipment conditions. However, develop

关键词： HV/MV Distribution Substations Maintenance Strategy RCM Optimization Asset Management

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Three Lemmas on Dynamic Cavity Method

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Communications in Theoretical Physics 2011年第7期56卷 157-162页

作者： Erik Aurell Hamed mahmoudi Department of Computational Biology AlbaNova University Centre Department of Information and Computer Science Aalto UniversityFinland

We study the dynamic cavity method for dilute kinetic Ising models with synchronous update rules. For the parallel update rule we find for fully asymmetric models that the dynamic cavity equations reduce to a Markovian dynamics of the (time-dependent) marginal probabilities. For the random sequential update rule, also an instantiation of a synchronous update rule, we find on the other hand that the dynamic cavity equations do not reduce to a Markovian dynamics, unless an additional assumption of time factorization is introduced. For symmetric models we show that a fixed point of ordinary Belief propagation is also a fixed point of the dynamic cavity equations in the time factorized approximation. For clarity, the conclusions of the paper are formulated as three lemmas.

关键词： kinetic Ising model cavity method disordered systems

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Improved double-gate armchair silicene nanoribbon field-effect-transistor at large transport bandgap

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Chinese Physics B 2016年第1期25卷 809-816页

作者： Mohsen mahmoudi Zahra Ahangari Morteza Fathipour Department of Electrical and Computer Engineering University of Tehran Young Researchers and Elite Club Yadegar-e-Imam Khomeini (RAH) Shahre-Rey Branch Islamic Azad University

The electrical characteristics of a double-gate armchair silicene nanoribbon field-effect-transistor （DG ASiNR FET） are thoroughly investigated by using a ballistic quantum transport model based on non-equilibrium Green＇s function （NEGF） approach self-consistently coupled with a three-dimensional （3D） Poisson equation. We evaluate the influence of variation in uniaxial tensile strain, ribbon temperature and oxide thickness on the on-off current ratio, subthreshold swing, transconductance and the delay time of a 12-nm-length ultranarrow ASiNR FET. A novel two-parameter strain mag- nitude and temperature-dependent model is presented for designing an optimized device possessing balanced amelioration of all the electrical parameters. We demonstrate that employing HfO2 as the gate insulator can be a favorable choice and simultaneous use of it with proper combination of temperature and strain magnitude can achieve better device performance. Furthermore, a general model power （GMP） is derived which explicitly provides the electron effective mass as a function of the bandgap of a hydrogen passivated ASiNR under strain.

关键词： silicene double-gate field-effect-transistor non-equilibrium Green's function tight binding

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Dual function of fungi-derived cytokines in inflammatory bowel diseases:protection or inflammation

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Gastroenterology Report 2023年第1期11卷 182-190页

作者： Niusha Sharifinejad Elaheh mahmoudi Non-Communicable Diseases Research Center Alborz University of Medical SciencesKarajIran Department of Mycology School of MedicineAlborz University of Medical SciencesKarajIran

Inflammatory bowel disease(IBD)is an immune-mediated inflammatory condition involving both the innate and adaptive immune ***,the role of intestinal fungal flora and their downstream immune pathways has been highlighted in the pathogenesis of *** as primary immune mediators require a delicate balance for maintaining intestinal *** most cytokines have a predictable role in either amplifying or attenuating inflammation in IBD,a few cytokines have shown a dual function in the inflammatory state of the *** of these dual-faced cytokines are also involved in mucosal anti-microbial defense pathways,particularly against intestinal fungal ***,we reviewed the role of these cytokines in IBD pathogenesis to achieve a better understanding of the fungal interactions in the development of IBD.

关键词： inflammatory bowel diseases IBD cytokines intestinal fungi fungi-derived cytokines

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Phase-controlled atom-photon entanglement in a three-level Λ-type closed-loop atomic system

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Chinese Physics B 2013年第6期22卷 211-217页

作者： Ali Mortezapour Zeinab Kordi Mohammad mahmoudi Institute for Advanced Studies in Basic Sciences P.O.Box 45195-159ZanjanIran Physics Department University of ZanjanP.O.Box 45195-313ZanjanIran

We study the entanglement of dressed atom and its spontaneous emission in a three-level A-type closed-loop atomic system in a multi-photon resonance condition and beyond it. It is shown that the von Neumann entropy in such a system is phase-dependent, and it can be controlled by either the intensity or relative phase of applied fields. It is demonstrated that for the special case of the Rabi frequency of applied fields, the system is disentangled. In addition, we take into account the effect of Doppler broadening on the entanglement and it is found that a suitable choice of laser propagation direction allows us to obtain the steady state degree of entanglement （DEM） even in the presence of the Doppler effect.

关键词： entanglement quantum entropy closed-loop system

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A location-based fog computing optimization of energy management in smart buildings:DEVS modeling and design of connected objects

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Frontiers of Computer Science 2023年第2期17卷 179-195页

作者： Abdelfettah MAATOUG Ghalem BELALEM Saïd mahmoudi Computer Science Department Faculty of Exact and Applied SciencesUniversity of Oran 1 Ahmed Ben BellaOran 31000Algeria Science and Technology Department Faculty of Science and TechnologyUniversity of TIARETTiaret 14000Algeria Computer Science Department Faculty of EngineeringUniversity of MonsMons 7000Belgium

Nowadays,smart buildings rely on Internet of things(loT)technology derived from the cloud and fog computing paradigms to coordinate and collaborate between connected *** is characterized by low latency with a wider spread and geographically distributed nodes to support mobility,real-time interaction,and location-based *** provide optimum quality of user life in moderm buildings,we rely on a holistic Framework,designed in a way that decreases latency and improves energy saving and services efficiency with different *** EVent system Specification(DEVS)is a formalism used to describe simulation models in a modular *** this work,the sub-models of connected objects in the building are accurately and independently designed,and after installing them together,we easily get an integrated model which is subject to the fog computing *** results show that this new approach significantly,improves energy efficiency of buildings and reduces ***,with DEVS,we can easily add or remove sub-models to or from the overall model,allowing us to continually improve our designs.

关键词： smart building energy consumption IoT fog computing Framework DEVS simulation models

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Gastrointestinal viral shedding in children with SARS‑CoV‑2:a systematic review and meta‑analysis

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World Journal of Pediatrics 2022年第9期18卷 582-588页

作者： Sepideh Benvari Shima mahmoudi Mohsen Mohammadi Department of Microbiology Faculty of MedicineQazvin University of Medical SciencesQazvinIran Pediatric Infectious Disease Research Center Tehran University of Medical SciencesTehranIran Non-Communicable Pediatric Diseases Research Center Health Research InstituteBabol University of Medical SciencesBabolIran

Background Coronavirus disease 2019(COVID-19)has diferent manifestations in pediatric *** is assumed that they might present more gastrointestinal symptoms with a diferent viral shedding pattern in gastrointestinal *** this systematic review and meta-analysis,we aimed to evaluate the viral shedding pattern in gastrointestinal specimens of children with *** We searched all published studies in English language in PubMed,Web of Science,and Scopus,up to date as of October *** search included the term"severe acute respiratory syndrome coronavirus 2,COVID-19,SARS-CoV-2,novel coronavirus,or coronavirus;and shed,excrete,secret,or carriage;and stool or rectal;and children or pediatrics".We included studies evaluating SARS-CoV-2 shedding in gastrointestinal specimens,including rectal swabs and stool samples of children with COVID-19 *** excluded duplicated data,case reports,and studies without original *** Twelve studies met the eligibility criteria for the qualitative synthesis,10 of which were included in the *** pooled prevalence of gastrointestinal severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)RNA in children with COVID-19 was 86%(95%confdence interval 73%–96%,I 2=62.28%).After respiratory specimen had become negative,72%(43/60)had persistent shedding in gastrointestinal *** gastrointestinal RNA had a positive test result for more than 70 days after symptoms *** Gastrointestinal shedding of SARS-CoV-2 might occur in a substantial portion of children and might persist long after negative respiratory *** research is recommended to fnd the role of SARS-CoV-2 gastrointestinal shedding in transmission in children.

关键词： Coronavirus disease 2019(COVID-19) Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) Viral shedding

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Synthesis of Flower-Like Nanoparticles of Anatase Titania by Microwave Solvo-Hydrothermal Method

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Acta Metallurgica Sinica(English Letters) 2013年第6期26卷 742-746页

作者： S.mahmoudi S.Boudjadar Ceramics Laboratory Department of PhysicsUniversity of Constantine

Anatase titania nanoparticles with an average size of about 14 nm were synthesized by microwave solvothermal method from TiCI4 and ethanol as a precursor and solvent respectively. The shapes of as prepared samples were modified by microwave hydrothermal treatment in strongly alkaline medium at 100℃ for 2 h, the agglomerate particles can be converted to the nanorods then to flower-like sphere. The structure, morphology and optical properties of as-prepared powders were investigated by X-ray diffraction, scanning electron microscopy and UV- vis absorption spectroscopy, the quality of the samples was examined by IR absorption spectroscopy and room temperature photoluminescence （PL）. The results showed that the synthesized Ti02 revealed the formation of the nanorods and the flower-like shape of titania after post treatment in 5 mol/L and 10 mol/L NaOH solution, respectively. IR absorption spectra showed that the as-prepared TiO2 nanocrystals were highly pure and strongly surface hydrated, The photoluminescence measurement showed that five main emission peaks appeared in UV, violet, blue and green regions.

关键词： Titanium dioxide Microwave hydrothermal Alkaline medium Flower-like Photoluminescence

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Temperature effect on performance of nanoparticle/surfactant flooding in enhanced heavy oil recovery

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Petroleum Science 2019年第6期16卷 1387-1402页

作者： Sajjad mahmoudi Arezou Jafari Soheila Javadian Department of Petroleum Engineering Faculty of Chemical EngineeringTarbiat Modares UniversityTehranIran Department of Physical Chemistry Faculty of Basic ScienceTarbiat Modares UniversityP.O.Box 14115-175TehranIran

Recently,nanoparticles have been used along with surfactants for enhancing oil *** the recent studies show that oil recovery is enhanced using nanoparticle/surfactant solutions,some effective parameters and mechanisms involved in the oil recovery have not yet been ***,the temperature effect on the stability of nanoparticle/surfactant solutions and ultimate oil recovery has been studied in this work,and the optimal concentrations of both SiO2 nanoparticle and surfactant(sodium dodecyl sulfate)have been determined by the Central Composite Design *** addition,the simultaneous effects of parameters and their interactions have been *** of the stability of the injected solutions indicates that the nanoparticle concentration is the most important factor affecting the solution *** surfactant makes the solution more stable if used in appropriate concentrations below the *** to the micromodel flooding results,the most effective factor for enhancing oil recovery is temperature compared to the nanoparticle and surfactant ***,in floodings with higher porous medium temperature,the oil viscosity reduction is considerable,and more oil is *** addition,the surfactant concentration plays a more effective role in reservoirs with higher *** other words,at a surfactant concentration of 250 ppm,the ultimate oil recovery is improved about 20%with a temperature increase of 20°***,when the surfactant concentration is equal to 750 ppm,the temperature increase enhances the ultimate oil recovery by only about 7%.Finally,the nanoparticle and surfactant optimum concentrations determined by Design-Expert software were equal to 46 and 159 ppm,*** is worthy to note that obtained results are validated by the confirmation test.

关键词： Enhanced heavy oil recovery Nanoparticle Surfactant Temperature High salinity brine Stability Micromodel Experimental design

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Entanglement in a two-spin system with long-range interactions

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Chinese Physics B 2016年第8期25卷 369-372页

作者： Soltani M R Mahdavifar S mahmoudi M Department of Physics College of Science Yadegar-e-Imam Khomeini (RAH) Shahre-Rey Branch Islamic Azad University Department of Physics University of Guilan

The quantum entanglement between two spins in the Ising model with an added Dzyaloshinsky–Moriya（DM） interaction and in the presence of the transverse magnetic field is studied. The exchange interaction is considered as a function of the distance between spins. The negativity as a function of magnetic field, exchange and DM interaction is *** effect of the distance between spins is studied based on the negativity. In addition, the effect of the thermal fluctuation on the negativity is also investigated.

关键词： entanglement Ising model DM interaction negativity long range interaction

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