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Defence Technology（防务技术） 2023年第4期22卷 69-73页

作者： bhargav appasani Avireni Srinivasulu Cristian Ravariu Department of Electronics Engineering Kalinga Institute of Industrial TechnologyBhubaneswarIndia Department of Electronics Engineering K R Mangalam UniversityGurgaonIndia Department of Electronic Devices Circuits and ArchitecturesPolytechnic University of BucharestBucharestRomania

A nearly perfect metamaterial absorber is proposed that can find utility in terahertz sensing *** design consists of two concentric elliptical ring resonators(ERRs)whose parameters are appropriately set to achieve dual band absorption with near perfect *** first absorption band at 3.62 THz having a Q-factor of 51.7 was caused due to the currents in the outer and inner *** second absorption peak at 3.814 THz having a Q factor of 1411.11 was a consequence of currents flowing across the gap between the two concentric ***,it is observed that the absorption bands are sensitive to the variation in refractive index of the surrounding *** sensitivity's in the absorption bands are 3 THz/RIU and 3.59 THz/RIU respectively.A sensor is proposed based on this design to detect harmful gases,which is demonstrated for detection of Methane and *** Q-factor and high sensitivity of the narrow band makes the design an excellent sensor for detecting variations in the refractive index.

关键词： Refractive index Plasma frequency Metamaterials Terahertz absorption Q-factor Gas sensing

Communication infrastructure for situational awareness enhancement in WAMS with optimal PMU placement

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Protection and Control of Modern Power Systems 2021年第1期6卷 124-135页

作者： bhargav appasani Amitkumar Vidyakant Jha Sunil Kumar Mishra Abu Nasar Ghazali School of Electronic Engineering KIIT UniversityBhubaneswar751024India

Real time monitoring and control of a modern power system has achieved significant development since the incorporation of the phasor measurement unit (PMU). Due to the time-synchronized capabilities, PMU has increased the situational awareness (SA) in a wide area measurement system (WAMS). Operator SA depends on the data pertaining to the real-time health of the grid. This is measured by PMUs and is accessible for data analytics at the data monitoring station referred to as the phasor data concentrator (PDC). Availability of the communication system and communication delay are two of the decisive factors governing the operator SA. This paper presents a pragmatic metric to assess the operator SA and ensure optimal locations for the placement of PMUs, PDC, and the underlying communication infrastructure to increase the efficacy of operator SA. The uses of digital elevation model (DEM) data of the surface topography to determine the optimal locations for the placement of the PMU, and the microwave technology for communicating synchrophasor data is another important contribution carried out in this paper. The practical power grid system of Bihar in India is considered as a case study, and extensive simulation results and analysis are presented for validating the proposed methodology.

关键词： Situational awareness Phasor measurement unit Optimal placement Microwave communication

A review on synchrophasor communication system:communication technologies,standards and applications

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Protection and Control of Modern Power Systems 2018年第1期3卷 392-408页

作者： bhargav appasani Dusmanta Kumar Mohanta School of Electronics Engineering KIIT UniversityBhubaneswar 751024India Department Electrical and Electronics Engineering Birla Institute of TechnologyMesra 835215India

The present-day power system is a complex network that caters to the demands of several applications with diverse energy *** a complex network is susceptible to faults caused due to several reasons such as the failure of the equipment,hostile weather conditions,*** faults if not detected in the real-time may lead to cascading failures resulting in a *** blackouts have catastrophic consequences which result in a huge loss of *** example,a blackout in 2004 caused an economic loss of 10 billion U.S dollars as per the report of the Electricity Consumers Resource *** investigation of the blackout revealed that the catastrophe could have been prevented if there was an early warning *** other blackouts across the globe forced the power system engineers to devise an effective solution for real-time monitoring and control of the power *** consequence of these efforts is the wide area measurement system(WAMS).The WAMS consists of several sensors known as the phasor measurement units(PMUs)that collect the real information pertaining to the health of the power *** information in the form time synchronized voltage and current phasors is communicated to the central control center or the phasor data concentrator(PDC)where the data is analyzed for detection of power system *** communication of the synchrophasor data from each PMU to the PDC constitutes the synchrophasor communication system(SPCS).Thus,the SPCS can be considered as the edifice of the WAMS and its reliable operation is essential for the effective monitoring and control of the power *** paper presents a comprehensive review of the various synchrophasor communication technologies,communication standards and *** also identifies the existing knowledge gaps and the scope for future research work.

关键词： Phasor measurement unit Wide area measurement system Synchrophasor communication system Communication standards Communication technologies Optimal placement

2,5-Dimercapto-1,3,4-Thiadiazole(DMCT)-Based Polymers for Rechargeable Metal-Sulfur Batteries

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Comparison of detached eddy simulation and standard k-ε RANS model for rack-level airflow analysis inside a data center

Energy & Environmental Materials 2023年第6期6卷 283-290页

作者： Amruth bhargav Arumugam Manthiram Materials Science and Engineering Program&Texas Materials Institute The University of Texas at AustinAustin Texas 78712USA

Organosulfur materials are a sustainable alternative to the present-day layered oxide cathodes in lithium-based *** such organosulfur material that was intensely explored from the 1990s to early 2010s is 2,5-dimercapto-1,3,4-thiadiazole(DMCT).However,research interest declined as the electrode reactions with DMCT were assumed to be too sluggish to be *** with the advances in metal-sulfur batteries,we revisit DMCT-based materials in the form of poly[tetrathio-2,5-(1,3,4-thiadiazole)],referred to as *** an appropriate choice of electrode design and electrolyte,pDMCT-S cathode paired with a Li-metal anode shows a capacity of 715 mA h g^(-1)and a Coulombic efficiency of 97.7%at a C/10 rate,thus quelling the concerns of sluggish ***,pDMCT-S shows significantly improved long-term cyclability compared to a sulfur *** into the origin of the stability reveals that the discharge product Li-DMCT in its mesomeric form can strongly bind to polysulfides,preventing their dissolution into the electrolyte and *** unique mechanism solves a critical problem faced by sulfur ***,this mechanism results in a stable performance of pDMCT-S with Na-metal cells as *** study opens the potential for exploring other organic materials that have inherent polysulfide sequestering capabilities,enabling long-life metal-sulfur batteries.

关键词： 2,5-dimercapto-1,3,4-thiadiazole electrochemistry metal-sulfur batteries organopolysulfide organosulfur batteries

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Building Simulation 2022年第9期15卷 1595-1610页

作者： Anashusen Saiyad Yogesh Fulpagare Atul bhargav Mechanical Engineering Energy Systems Research LaboratoryIndian Institute of Technology GandhinagarPalajGandhinagarGJ382355India

High computing demands and data privacy regulations from many countries in the world have resulted in the expansion of data *** this,energy consumption by data centers has increased to an alarming *** centers are highly dynamic due to time-dependent server heat generation and cold-hot aisle arrangements,making it difficult to have real-time control for efficient thermal *** cooling strategies based on conservative set points affect energy *** of expensive field measurements,CFD analysis of the flow field inside the data center can provide insightful data to assist the heat release from the *** detailed rack-level flow field inside the data center is missing in the literature as most of the studies are based on approximate results using the RANS-based k-ε ***,DES-based models have shown the ability to resolve complex flow *** this finding,rack-level CFD analysis of the data center is performed using DES and standard k-ε *** first,average rack inlet and outlet air temperatures in steady-state were validated with experiments within the accuracy of 1.4℃.The distributions of turbulent kinetic energy and mean velocity inside the cold aisle were *** recirculation region in the cold aisle was well-captured by the DES and qualitatively validated with the experiments compared to the k-e *** k-ε model failed to predict SHI,RTI,and/3 metrics,whereas the DES model successfully captured recirculation and self-heating of the upper *** acceptable trade-off between computational cost and accuracy for the simulations would be a pivotal parameter for the selection of either DES or the k-ε model for the data center CFD *** porous media assumption of the servers can bring uncertainties for turbulent quantities and hence further DES model for a data center can provide additional insights in this study.

关键词： data center CFD DES RANS thermal management

Integration of evacuated solar collectors with an adsorptive ice maker for hot climate region

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Energy and Built Environment 2022年第2期3卷 181-189页

作者： Nishant Modi bhargav Pandya College of Sciences and Engineering University of TasmaniaTasmaniaAustralia School of Chemical Engineering University of BirminghamBirminghamUnited Kingdom

This research study compares the steady-state and dynamic behaviour of a solar-powered activated carbon-35(AC35)/methanol-based vapour adsorption refrigeration system for production of ice at hot climate ***-modynamic comparisons are made with the coefficient of performance(COP),system COP(SCOP),specific refrig-eration capacity(SRC)and critical parameters such as cycle time and ice production rate are ***,the sustainability of the proposed ice maker has proven by integrating economic and environmental *** minimum solar flux required to ensure continuous ice production was found 800 W/m^(2).Moreover,the max-imum ice production rate and COP were decreased by 32.36%and 37.63%respectively when the system was operated under real ambient *** proposed solar adsorptive ice maker achieved maximum SRC of 61.6 g m^(−2)during April month and reduced the CO_(2)emissions by 12.82 ton annually.

关键词： Solar cooling system Adsorption refrigeration cycle Ice production rate Activated carbon-35(AC35)/Methanol GHG emissions Simple payback period

Misalignment Between Skills Discovered, Disseminated, and Deployed in the Knowledge Economy

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Journal of Social Computing 2022年第3期3卷 191-205页

作者： bhargav Srinivasa Desikan James Evans the Department of Computer and Communication Sciences École Polytechnique Fédérale de Lausanne(EPFL)Lausanne 1015Switzerland the Knowledge Lab the Department of SociologyUniversity of ChicagoChicagoIL 60615USAand also with the Santa Fe InstituteSanta FeNM 87501USA

The knowledge economy is a complex and dynamical system,where knowledge and skills are discovered through research,diffused via education,and deployed by *** aligning the supply of new knowledge with the demand for practical skills through education is critical for developing national innovation systems that maximize human *** this paper,we evaluate the complex alignment of skills across the knowledge economy by creating an integrated semantic model that neurally encodes invented,instructed,and instituted skills across three major datasets:research abstracts from the Web of Science,teaching syllabi from the Open Syllabus Project,and job advertisements from Burning *** the high dimensional knowledge and skills space inscribed by these data,we draw critical insight about systemic misalignment between the diversity of skills supplied and demanded in the knowledge *** with insights from economic geography,demand for skills from industry exhibits high entropy(diversity)at local,regional,and national levels,demonstrating dense complementarities between them at all levels of the *** with the economics and sociology of innovation,we find low entropy in the invention of new knowledge and skills through research,as specialist researchers cluster within *** provide new evidence,however,for the low entropy of skills taught at local,regional,and national levels,illustrating a massive mismatch between diversity in skills supplied versus *** misalignment is sustained by the spatial and institutional mismatch in the organization of education by researchers at the site of skill invention over *** findings suggestively trace the societal costs of tethering education to researchers with narrow knowledge rather than students with broad skill needs.

关键词： computational content analysis knowledge economy sociology of knowledge natural language processing data science and society

Tailoring of structural,optical and electrical properties of anatase TiO_(2)via doping of cobalt and nitrogen ions

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Journal of Materials Science & Technology 2022年第16期111卷 287-297页

作者： Anchal Sharma Puneet Negi Ruhit Jyoti Konwar Hemaunt Kumar Yogita Verma Shailja Prakash Chandra Sati bhargav Rajyaguru Himanshu Dadhich N.A.Shah P.S.Solanki Department of Physics Eternal UniversityBaru SahibHimachal Pradesh173101India Centre of Excellence in Energy Science and Technology Shoolini UniversitySolanHimachal Pradesh173229India Department of Applied Science and Humanities Rajkiya Engineering CollegeBijnorUttar Pradesh246725India Department of Physics Rajiv Gandhi Government Post Graduate CollegeMandsaurMadhya Pradesh458001India Department of Physics Saurashtra UniversityRajkot360005India

Pure(pristine)anatase and mono–doped and co–doped derivatives of TiO_(2)having nitrogen(N)and cobalt(Co)as dopants with respective fixed doping concentrations of 0.7 mol.%and 1.0 mol.%were synthesized using auto–combustion sol–gel *** doping effects at corresponding non–metal and transition metal sites of TiO_(2)on the basis of the structural,optical and electrical properties have been investigated.X–ray diffraction(XRD)measurement confirms the formation of pure anatase phase of TiO_(2)for all samples having I41/amd space group of tetragonal structure which has been also verified by the Raman spectroscopy *** crystallographic parameters have been calculated by performing Rietveld refinement of XRD data including average crystallite size that has been observed in the range of10–15 *** anatase phase indicates the incorporation of Co^(2+)into TiO_(2)lattice which assists the substitution of N in place of oxygen in co–doped TiO_(2).The band gap tuning towards the visible region from3.2 to 2.1 e V has been achieved with mono–doping and co–doping of the N and Co in TiO_(2)*** can be described in terms of the formation of localized levels of N–2p and Co–3d states in mono–doping and an isolated intermediate band formation in co–doping *** properties have been investigated in details and explained as the synergetic effects of structural and inherent ionic characters of various *** observed band gaps of all doped samples lie within the visible region which makes them pertinent as the solar energy harnessing materials for photocatalytic and photovoltaic applications.

关键词： TiO_(2) Sol–Gel X–ray diffraction Electrical properties Optical properties

Heuristic polling sequence to enhance sleep count of EPON

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Frontiers of Optoelectronics 2019年第4期12卷 422-432页

作者： bhargav Ram RAYAPATI Nakkeeran RANGASWAMY Department of Electronics Engineering Pondicherry UniversityPondicherry 605014India

Next-generation passive optical networks(PONs)demand power conservation to create a green environment.A reduction in power consumption of the traditional Ethernet passive optical network(EPON)can be achieved by increasing the sleep count in optical network units(ONUs).In this paper,this is accomplished by introducing a first-in-last-out(FILO)polling sequence in the place of a fixed polling sequence to increase the number of ONUs entering sleep mode(sleep count).In a fixed polling sequence,the optical line terminal(OLT)allocates idle time to the ONUs based on the overall load of the *** leads to a situation that whenever the idle time does not meet the wakeup time threshold of sleep mode,the ONUs are put into doze/active mode,which consumes more *** the FILO polling sequence,the first polled ONU in the current cycle is made to be polled last in the following *** continues in this way,and by this rearrangement,the idle time of delayed poll ONUs increases;hence,it helps to reduce the power ***,a modified load adaptive sequence arrangement(MLASA)method is suggested,where the ONUs are categorized into doze ONUs and sleep ONUs.A numerical simulation of the FILO polling sequence with a vertical cavity surface emitting laser(VCSEL)ONU shows a maximum reduction in power consumption of 15.5 W and a 20%improvement in energy savings compared with the traditional fixed polling *** MLASA method results in better power consumption with minimum delay than that of the proposed FILO and existing LASA methods.

关键词： Ethernet passive optical network(EPON) optical network unit(ONU) polling sequence power conservation

Bridging electrical power and entropy of ONU in EPON

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Optoelectronics Letters 2021年第2期17卷 102-106页

作者： bhargav Ram Rayapati Nakkeeran Rangaswamy Department of Electronics Engineering School of Engineering and TechnologyPondicherry UniversityPondicherry 605014India

This letter deliberates bridging of overall electricity power requirements of the optical network unit(ONU) with the entropy noted through the ONU state transition models considered in ethernet passive optical network(EPON). The entropy depends on the steady state and transition probabilities of data. On the other hand, the power requirements(consumption) of ONUs depend on the steady sate probability of ONUs. The potential relation derived between the entropy and electrical power reveals that they related exponentially but for their logarithmic reliance. Also, the relation is validated through the numerical simulation. The deduced relation has its importance to understand the nuances of one entity given the other.

关键词： power ONU network