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Estimation of composite load model with aggregate induction motor dynamic load for an isolated hybrid power system

Frontiers in Energy 2015年第4期9卷 472-485页

作者： nitin kumar SAXENA Ashwani kumar SHARMA Deptment of Electrical Engineering NIT Kumkshetra Haryana 136119 India

It is well recognized that the voltage stability of a power system is affected by the load model and hence, to effectively analyze the reactive power compensation of an isolated hybrid wind-diesel based power system, the loads need to be considered along with the generators in a transient analysis. This paper gives a detailed mathematical modeling to compute the reactive power response with small voltage perturbation for composite load. The composite load is a combination of the static and dynamic load model. To develop this composite load model, the exponential load is used as a static load model and induction motors （IMs） are used as a dynamic load model. To analyze the dynamics of IM load, the fifth, third and first order model of IM are formulated and compared using differential equations solver in Matlab coding. Since the decentralized areas have many small consumers which may consist large numbers of IMs of small rating, it is not realistic to model either a single large rating unit or all small rating IMs together that are placed in the system. In place of using a single large rating IM, a group of motors are considered and then the aggregate model of IM is developed using the law of energy conservation. This aggregate model is used as a dynamic load model. For different simulation studies, especially in the area of voltage stability with reactive power compensation of an isolated hybrid power system, the transfer function AQ/AV of the composite load is required. The transfer function of the composite load is derived in this paper by successive derivation for the exponential model of static load and for the fifth and third order IM dynamic load model using state space model.

关键词： isolated hybrid power system (IHPS) compo- site load model static load dynamic load induction motorload model aggregate load

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Determining Potential Passive Islanding Detection Indicators for Single-point Single Inverter,Single-point Multi-inverter and Multi-point Multi-inverter Scenarios

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CSEE Journal of Power and Energy Systems 2022年第3期8卷 696-709页

作者： nitin kumar Kulkarni Mohan Khedkar Department of Electrical Engineering Visvesvaraya National Institute of TechnologyNagpurIndia

Distributed Generation(DG)sources,predominantly renewable energy-based,such as solar photovoltaic and wind energy sources,have significantly penetrated into power system *** high penetration of DG sources may lead to the formation of unintentional islands,which is hazardous to both the equipment and personnel,if *** this paper,46 passive parameters are considered to find out which candidate(s)are promising for detecting sustained unintentional islands and avoid false DG *** 46 parameters are derived from point of common coupling(PCC)voltage,DG output current,frequency,power factor angle,active and reactive *** these parameters are tested on standard IEEE 13 and 34 bus distribution networks,integrated with inverter-interfaced DGs at different locations for different penetration levels in the MATLAB/SIMULINK *** parameters are tested for different islanding events(comprising of various local loads,such as conventional parallel RLC resonant load,R,RC,and RL loads)and for different non-islanding *** parameters are then ranked accordingly by a suitable averaging approach based performance ranking *** this analysis,the best candidates are obtained for detecting inverter DG islands at single-point(or single PCC)locations and multi-point(or multiple PCCs)*** best passive candidates are obtained for different island scenarios from which a set of promising islanding detection indicators are proposed.

关键词： Averaging approach inverter DG point of common coupling(PCC) passive parameters test system

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Weight loss endoscopy: Development, applications, and current status

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World Journal of Gastroenterology 2016年第31期22卷 7069-7079页

作者： nitin kumar Bariatric Endoscopy Institute

Obesity and its comorbidities- including diabetes and obstructive sleep apnea- have taken a large and increasing toll on the United States and the rest of the world. The availability of commercial, clinical, and operative therapies for weight management have not been effective at a societal level. Endoscopic bariatric therapy is gaining acceptance as more effective than diet and lifestyle measures, and less invasive than bariatric surgery. Various endoscopic therapies are analogues of the restrictive or bypass components of bariatric surgery, utilizing gastric remodeling or intestinal anastomosis to achieve proven weight loss and metabolic benefits. Others, such as aspiration therapy, employnovel mechanisms of action. Intragastric balloons have recently been approved by the United States Food and Drug Administration, and a number of other technologies have completed large multicenter trials(such as AspireA ssist aspiration therapy and Primary Obesity Surgery Endolumenal). Endoscopic sleeve gastroplasty and transoral outlet reduction for endoscopic revision of gastric bypass have proven safe and effective in a number of studies. As devices are approved for use, data will continue to accumulate for safety, effectiveness, and cost effectiveness. Bariatric endoscopists should be prepared to appropriately target and apply various endoscopic bariatric therapies in the context of a comprehensive long-term weight management program.

关键词： Weight loss Intragastric balloon Gastric balloon Orbera Reshape dual balloon Endoscopic sleeve Endoscopic sleeve gastroplasty Primary Obesity surgery endolumenal Gastric bypass Gastric bypass revision Obesity

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Reactive power compensation of an isolated hybrid power system with load interaction using ANFIS tuned STATCOM

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Frontiers in Energy 2014年第2期8卷 261-268页

作者： nitin SAXENA Ashwani kumar Department of Electrical Engineering National Institute of Technology Kurukshetra 136119 India

This paper presents an adaptive neuro fuzzy interference system （ANFIS） based approach to tune the parameters of the static synchronous compensator （STAT- COM） with frequent disturbances in load model and power input of a wind-diesel based isolated hybrid power system （IHPS）. In literature, proportional integral （PI） based controller constants are optimized for voltage stability in hybrid systems due to the interaction of load disturbances and input power disturbances. These conventional controlling techniques use the integral square error （ISE） criterion with an open loop load model. An ANFIS tuned constants of a STATCOM controller for controlling the reactive power requirement to stabilize the voltage variation is proposed in the paper. Moreover, the interaction between the load and the isolated power system is developed in terms of closed loop load interaction with the system. Furthermore, a comparison of transient responses of IHPS is also presented when the system has only the STATCOM and the static compensation requirement of the induction generator is fulfilled by the fixed capacitor, dynamic compensation requirement, meanwhile, is fulfilled by STATCOM. The model is tested for a 1% step increase in reactive power load demand at t = 0 s and then a sudden change of 3% from the 1% at t = 0.01 s for a 1% step increase in power input at variable wind speed model.

关键词： isolated wind-diesel power system adaptive neuro fuzzy interference system (ANFIS) integral square error (ISE) criterion load interaction

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Near real-time characterisation of urban environments: a holistic approach for monitoring dengue fever risk areas

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International Journal of Digital Earth 2014年第11期7卷 916-934页

作者： Muhammad Shahzad Sarfraz nitin kumar Tripathi Asanobu Kitamoto Department of Computer Science COMSATS Institute of Information Technology(CIIT)AbbottabadPakistan Remote Sensing and GIS Asian Institute of Technology(AIT)BangkokThailand Digital Content and Media Sciences Research Division National Institute of Informatics(NII)TokyoJapan

Despite frequent use of digital devices in everyday life,cost-effective measurement of public health issues in urban areas is still *** study was,therefore,planned to extract land-use types using object-based and spatial metric approaches to explore the dengue incidence in relation to the surrounding environment in near real-time using Google and Advanced Land Observation Satellite *** characterised image showed useful classification of an urban areawith 77%accuracy and 0.68 *** analysis on public health data indicated that most of the dengue cases were found in densely populated areas surrounded by dense *** living in independent houses having sparsely vegetated surroundings were found to be less *** incidence was more prevalent in people of 5-24 years of age(67%);while in terms of occupation,mostly students,the unemployed,labourers and farmers(88%)were *** general,males were affected slightly more(10%)than *** analyses indicated that most of the dengue cases were around institutions(40%),religious places(18%)and markets(15%).Thus,usage of Digital Earth scalable tools for monitoring health issues would open new ways for maintaining a healthy and sustainable society in the years ahead.

关键词： dengue fever land-use land-cover monitoring dengue risk urban environment object-based classification

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Production of biodiesel from unused algal biomass in Punjab, India

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Petroleum Science 2018年第1期15卷 164-175页

作者： Rachan Karmakar Anita Rajor Krishnendu Kundu nitin kumar School of Energy and Environment Thapar University Department of Biofuel CSIR CMERI Co EFM Department of Mechanical Engineering Thapar University

Biodiesel from inedible sources has become prominent in last few decades. But it is economically incompatible with petroleum diesel. At the same time, both petro-diesel and biodiesels are concerned with environmental pollution, global warming, etc. Algae, on the other hand, utilize CO2 for their growth and can minimize some sort of pollution level and results in carbon credit for a country. In Punjab, India, algae are seen to grow in many water bodies. But all those are taken away and dumped in vats. Some of this huge biomass was used for production of biodiesel in this work. Extraction of oil from algae was conducted by using Soxtherm（solvent extraction）. An amount of 9 wt% of algal oil was extracted by comparatively costly hexane, whereas 8% extraction was done by cheaper acetone. In the transesterification reaction, molar ratio（methanol： oil） of 6：1, catalyst（KOH） concentration of 3 wt%, reaction temperature of 60 °C, 60 min reaction time and a settling time of 2.5 h were found to be optimum conditions to get maximum ester with minimum free fatty acid content and viscosity. A statistical analysis for the transesterification procedure also showed a methanol-to-oil molar ratio of 6：1 and catalyst concentration of 3 wt% to be the optimum. Characterization of biodiesel was done and compared with ASTM/BIS standards. Most important properties of biodiesel ester like viscosity（3.12 c St or 3.12 mm2/s）, cloud and pour point（-1 and-6 °C, respectively）, flash and fire point（153 and 158 °C）, carbon residue content（0.03%）, acid number（0.36 mg of KOH/gm） were within the range of concerned standards.

关键词： Algae Biodiesel Biodiesel properties Transesterification Oil extraction

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Ameliorative Effects of Paclobutrazol via Physio-Biochemical and Molecular Manifestation in Rice under Water Deficit Stress

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Rice science 2024年第5期31卷 603-616,I0065页

作者： Chirag MAHESHWARI nitin kumar GARG Archana SINGH Aruna TYAGI Indian Council of Agricultural Research-Indian Agricultural Research Institute New Delhi 110012India Sri Karan Narendra Agricultural University JobnerRajasthan 303329India

To comprehensively explore the physio-biochemical and molecular changes of paclobutrazol(PBZ) at the ideal dose under water deficit stress(WDS) conditions, we investigated the effects of 100 mg/kg PBZ applied via drenching on various physio-biochemical and molecular parameters in three rice varieties(N22, IR64, and IR64 DTY1.1) under both mild [75%-80% relative water content(RWC)] and severe(60%-65% RWC) WDS conditions. The results showed that PBZ treatment positively influenced the physio-biochemical parameters, significantly increasing dry matter(16.27%-61.91%), RWC(6.48%-16.34%), membrane stability index(4.37%-10.35%), and total chlorophyll content(8.97%-29.09%) in the rice varieties under both mild and severe WDS. Moreover, PBZ treatment reduced drought susceptibility(0.83-0.95) and enhanced drought tolerance efficiency(60.92%-86.78%), indicating its potential as a stress-mitigating agent. Global methylation analysis revealed changes in DNA methylation patterns, indicating the regulatory influence of PBZ on gene expression. The expression analysis of genes involved in the diversification of geranylgeranyl pyrophosphate towards the biosynthesis of abscisic acid, gibberellin acid, and chlorophyll showed alterations in their expression levels, suggesting the involvement of PBZ in the isoprenoid pathway. Overall, this study provides valuable insights into the potential mechanisms by which PBZ modulates physiological and molecular responses in rice plants under WDS. The findings highlight the importance of PBZ as a promising agent for enhancing drought tolerance in rice and offer valuable information for future research in crop stress management.

关键词： rice paclobutrazol drought stress abscisic acid gibberellic acid

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Development of lead-free multifunctional materials Bi(Co_(0.45Ti0.45Fe0.10)O3

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Progress in Natural Science:Materials International 2018年第3期28卷 308-314页

作者： nitin kumar Alok Shukla R.N.P.Choudhary Department of Physics National Institute of Technology Mizoram Department of Physics Siksha ‘O′Anusandhan University

A lead free multiferroic material,Bi(Co0.45Ti0.45Fe0.10)O3（BCTF45/10）was synthesized by a solid-state reaction route at high ***45/10 powder was prepared using appropriate raw maretials in oxide powders with methanol ***-prepared circular shaped pellets were sintered at 1053 K for 6 h to produce a compact *** structural properties and elemental analysis were determined using X-ray diffraction and energy-dispersive X-ray spectroscopy techniques respectively at room *** microstructure or surface morphology of the sintered sample was carried out by using field emission scanning electron microscope（FE-SEM）.The XRD analysis shows that the compound exhibits the single-phase of orthorhombic *** average crystallite size estimated using the Scherrer's technique was found to be 30 *** influence of Co and Ti substitution（at Bi and Ti sites of Bi Fe O3）on some physical and electrical properties of Bi Fe O3was examined by using phase sensitive multimeter in a wide frequency and temperature *** magnetic nature of the sample was studied using vibrating sample *** of room temperature magnetic hysteresis loop exhibits the enhanced ferromagnetic characteristic with saturation magnetization of 5.091 emu/g and coercive field of 0.213 k Oe *** enhanced magnetic properties highlight various potential applications of Co/Ti doped BCTF45/10 materials.

关键词： Multifunctional material Dielectric constant and loss Electrical characteristics Impedance spectroscopy

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Operation makalu air crash:influence of cognitive and human factors on decision-making

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Forensic Sciences Research 2022年第4期7卷 803-807页

作者： Samarika Dahal Gopal kumar Chaudhary nitin kumar Agrawal Department of Dentistry Institute of MedicineKathmanduNepal Department of Forensic Medicine Maharajgunj Medical CampusMaharajgunjKathmanduNepal

Two onboard crew members lost their lives in the fatal Makalu Air Cessna Grand Caravan 208B domestic cargo flight crash on May 16,*** Disaster Victim Identification(DVI)procedure comprises external examination,photography,DNAcollection,fingerprint collection,postmortem examination,antemortem information collection from the family members,and *** major challenge of this operation was dealing with cognitive *** antemortem dental information of one of the deceased was revealed to the forensic experts just before the postmortem *** influenced the testing *** was a tendency to neglect the complete dental examination presuming the identification was ***,during a thorough examination,the forensic odontologist realised that the initial decision was ***,there are few experience-based resources available to resolve cognitive bias *** authors begin by summarising complicated operations in which they have been involved,followed by a discussion of the key sources of cognitive bias along with the solution to resolve these issues in DVI preparedness planning.

关键词： Forensic sciences disaster cognitive bias dental identification mortuary Nepal

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Effects of urea,metal ions and surfactants on the binding of baicalein with bovine serum albumin

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Journal of Pharmaceutical Analysis 2016年第4期6卷 256-267页

作者： Atanu Singha Roy Amit kumar Dinda nitin kumar Pandey Swagata Dasgupta Department of Chemistry Indian Institute of Technology

The interaction of baicalein with bovine serum albumin（BSA） was investigated with the help of spectroscopic and molecular docking *** binding affinity of baicalein towards BSA was estimated to be in order of 10~5 M^（-1） from fluorescence quenching *** ΔH°（-5.66 ＋ 0.14 kJ/mol） and positive（ΔS°）（＋ 79.96 ＋ 0.65J/mol K） indicate the presence of electrostatic interactions along with the hydrophobic forces that result in a positive ΔS°.The hydrophobic association of baicalein with BSA diminishes in the presence of sodium dodecyl sulfate（SDS） due to probable hydrophobic association of baicalein with SDS,resulting in a negative ΔS°（-40.65 ＋ 0.87 J/mol K）.Matrix-assisted laser desorption ionization/time of flight（MALDI-TOF） experiments indicate a 1：1 complexation between baicalein and *** unfolding and refolding phenomena of BSA were investigated in the absence and presence of baicalein using steady-state and fluorescence lifetime *** was observed that the presence of urea ruptured the non-covalent interaction between baicalein and *** presence of metal ions（Ag~＋,Mg^（2＋）,Ni^（2＋）,Mn^（2＋）,Co^（2＋） and Zn^（2＋）） increased the binding affinity of ligand towards *** changes in conformational aspects of BSA after ligand binding were also investigated using circular dichroism（CD） and Fourier transform infrared（FT-IR） spectroscopic *** selectivity studies following molecular docking analyses indicated the binding of baicalein to site 1（subdomain MA） of BSA.

关键词： Bovine serum albumin(BSA) Baicalein Binding constant Fluorescence spectroscopy Molecular docking

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