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A New Design Approach for Nearly Linear Phase Stable IIR Filter using Fractional Derivative

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IEEE/CAA Journal of Automatica Sinica 2020年第2期7卷 527-538页

作者： nikhil Agrawal Anil kumar Varun Bajaj Department of Electronics and Communication Engineering PDPM Indian Institute of Information TechnologyDesign and Manufacturing JabalpurMadhya Pradesh 482005India

In this paper,a new design method for digital infinite impulse response(IIR)filters with nearly linear-phase response is presented using fractional derivative constraints(FDCs).In the proposed method,design problem of an IIR frlter is constructed as the minimization of phase error between the desired and designed phase response of an allpass filter(APF)such that the designed lowpass filter(LPF)or highpass frlter(HPF)yields less passband(ep),and stopband errors(es)with optimal stopband attenuation(As).In order to have accurate passband(pb)response,FDCs are imposed on appropriate reference frequency,where the optimality of these FDCs are ensured by using a new greedy based sorting *** simulated results reflect the efficiency of the proposed method in term of improved passband response along with better transition ***,small reduction in^is observed within the allowable limit,when compared to noin-fractional design approach,but the designed filter remains immune to wordlength(WL)effect.

关键词： Fractional derivative constraint(FDC) infinite impulse response(IIR)filter least squared linear phase quantization

Recent advances in catalytic combustion of AP-based composite solid propellants

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Defence Technology（防务技术） 2021年第3期17卷 1013-1031页

作者： Narendra Yadav Prem kumar Srivastava Mohan varma Department of Space Engineering&Rocketry India Department of Chemistry Birla Institute of TechnologyMesraRanchiIndia

Composite solid propellants(CSPs) have widely been used as main energy source for propelling the rockets in both space and military applications. Internal ballistic parameters of rockets like characteristic exhaust velocity, specific impulse, thrust, burning rate etc., are measured to assess and control the performance of rocket motors. The burn rate of solid propellants has been considered as most vital parameter for design of solid rocket motors to meet specific mission requirements. The burning rate of solid propellants can be tailored by using different constituents, extent of oxidizer loading and its particle size and more commonly by incorporating suitable combustion catalysts. Various metal oxides(MOs),complexes, metal powders and metal alloys have shown positive catalytic behaviour during the combustion of CSPs. These are usually solid-state catalysts that play multiple roles in combustion of CSPs such as reduction in activation energy, enhancement of rate of reaction, modification of sequences in reaction-phase, influence on condensed-phase combustion and participation in combustion process in gas-phase reactions. The application of nanoscale catalysts in CSPs has increased considerably in recent past due to their superior catalytic properties as compared to their bulk-sized counterparts. A large surface-to-volume ratio and quantum size effect of nanocatalysts are considered to be plausible reasons for improving the combustion characteristics of propellants. Several efforts have been made to produce nanoscale combustion catalysts for advanced propellant formulations to improve their energetics. The work done so far is largely scattered. In this review, an effort has been made to introduce various combustion catalysts having at least a metallic entity. Recent developments of nanoscale combustion catalysts with their specific merits are discussed. The combustion chemistry of a typical CSP is briefly discussed for providing a better understanding on role of co

关键词： Composite solid propellants Burn rate modifier Metallic nano-catalysts Catalytic combustion Thermal decomposition

Geochemical signatures of potassium metasomatism in anthracite from the Himalayan fold‑thrust belts of Sikkim,India

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International Journal of Coal Science & Technology 2022年第2期9卷 48-69页

作者： Santanu Ghosh Anwita Ojha Atul kumar varma Coal Geology and Organic Petrology Laboratory Department of Applied GeologyIndian Institute of Technology(Indian School of Mines)DhanbadJharkhand 826004India Department of Earth Sciences Indian Institute of Technology BombayPowaiMumbaiMaharashtra 400076India

The present study focuses on the inorganic geochemical features of the bituminous coal samples from the Raniganj and the Jharia Basins,as well as the anthracite samples from the Himalayan fold-thrust belts of Sikkim,*** SiO_(2)content(48.05 wt%to 65.09 wt%and 35.92 wt%to 50.11 wt%in the bituminous and anthracite samples,respectively)and the ratio of Al_(2)O_(3)/TiO_(2)(6.97 to 17.03 in the bituminous coal samples and 10.34 to 20.07 in the anthracite samples)reveal the intermediate igneous source rock composition of the *** ratio of the K_(2)O/Al_(2)O_(3)in the ash yield of the bituminous coal samples(0.03 to 0.09)may suggest the presence of kaolinite mixed with montmorillonite,while its range in the ash yield of the anthracite samples(0.16 to 0.27)may imply the presence of illite mixed with *** chemical index of alteration values may suggest the moderate to strong chemical weathering of the source rock under sub-humid to humid climatic *** plot of the bituminous coal samples in the A–CN–K diagram depicts the traditional weathering trend of parent rocks,but the anthracite samples plot near the illite feld and are a bit ofset from the weathering *** may imply the plausible infuences of the potassium-metasomatism at post coalifcation stages,which is further supported by high K_(2)O/Na_(2)O ratio(29.88–80.13).The Fourier transform infrared spectra further reveal the hydroxyl stretching intensity of illite in the anthracite samples substantiating the efect of the epigenetic *** decrease in total kaolinite intensity/compound intensity of quartz and feldspar may provide additional evidence towards this epigenetic event.

关键词： Himalayan fold-thrust belts Anthracite Potassium metasomatism Kaolinite to quartz-feldspar intensity ratio Montmorillonite stretching and bending intensities Illite-stretching frequency

Chaos control in a discrete-time predator-prey model with weak Allee effect

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International Journal of Biomathematics 2018年第7期11卷 123-148页

作者： Saheb Pal Sourav kumar Sasmal nikhil Pal Department of Mathematics Visva-Bharati Santiniketan 731235India Department of Physics and Mathematics Aoyama Gakuin University Kanagawa 252-5258Japan

The stability of the predator-prey model subject to the Allee effect is an interesting topic in recent *** this paper,we investigate the impact of weak Allee effect on the stability of a discrete-time predator-prey model with Holling type-IV functional *** mathematical features of the proposed model are analyzed with the help of equilibrium analysis,stability analysis,and bifurcation *** provide sufficient conditions for the flip bifurcation by considering Allee parameter as the bifurcation *** observe that the model becomes stable from chaotic dynamics as the Allee parameter ***,we observe bi-stability behavior of the model between only prey existence equilibrium and the coexistence *** analytical findings are illustrated through numerical simulations.

关键词： Chaos control Allee effect flip bifurcation bi-stability Lyapunov exponent

Nanosecond pulse discharge based nitrogen oxides treatment using different electrode configurations

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High Voltage 2017年第2期2卷 60-68页

作者： Sankarsan Mohapatro Srikanth Allamsetty Apeksha Madhukar nikhil kumar Sharma DEI Lab School of Electrical SciencesIndian Institute of Technology BhubaneswarBhubaneswarOdisha 751013India HV Lab Department of Electrical EngineeringIndian Institute of ScienceBangaloreKarnataka 560012India

Nowadays,the intensity of air pollution,due to the industries and automobiles,has been increasing *** oxides(NO_(X))are one of the most harmful pollutants,which are getting released from both automobile and stationary diesel *** essentially need to be removed from the exhaust using after treatment ***,the energy required to remove these pollutants is one of the major considerations in selecting the technology for pollutant removal from diesel engine exhaust.A study has been carried out on the non-thermal plasma-based NO_(X) removal technique using various combinations of power supply units and electrode *** different electrode configurations are tested,in which two are cylindrical electrodes with diameters 3 and 5 mm,and the other one is a square electrode with a diagonal of 5 mm.A comparison is made between the results with two different pulse power supply units,PS-I:high-voltage direct current test set based and PS-II:DC–DC converter *** square electrode with PS-Ⅱhas been found to be the optimal combination,which has removed 85%of NO_(X) from the exhaust at an energy density of 55.5 J/L,when the initial NO_(X) concentration in the exhaust is 388 ppm.

关键词： electrode removed treatment

Assessment of self-reacting bobbin tool friction stir welding for joining AZ31 magnesium alloy at inert gas environment

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Journal of Magnesium and Alloys 2019年第4期7卷 661-671页

作者： Prakash kumar Sahu nikhil P Vasudevan Bipul Das Sukhomay Pal Department of Mechanical Engineering and IDM Joint Lab Tsinghua UniversityBeijing 100084China Larsen and Toubro Limited HaziraSuratGujarat 394510India Department of Mechanical Engineering National Institute of Technology Silchar788010 AssamIndia Department of Mechanical Engineering Indian Institute of Technology Guwahati781039 AssamIndia

Research work presented in this study has the primary target of exploring joint attributes of AZ31 magnesium alloys using friction stir welding process with a modified tool referred as bobbin *** of inert and open atmosphere on mechanical properties are evaluated over a wide range of welding speed and tool rotation *** of the research findings from the inert atmosphere bobbin tool were made with the traditional process of friction stir *** results depicted improved joint properties for inert atmosphere *** and intermediate range of tool rotational speed is found to be favorable for bobbin tool friction stir welding without and with an inert medium,*** atmosphere due to inert medium leads to less oxidation of the AZ31 Mg alloy leading to superior joint *** investigations are also made with the aim of evaluating the impact of bobbin tool and inert medium on joint *** each aspect for joining of AZ31 Mg alloy,bobbin tool with inert medium is found to be an effective solution for joining with improved mechanical properties compared to without inert bobbin tool as well as conventional tool friction stir welding.

关键词： Mg FSW Bobbin tool Process parameters Mechanical properties Fractography Microstructural characterization

Polytene chromosomes of an Indian Himalayan black fly Simulium (Nevermannia) praelargum (Diptera:Simuliidae)

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Current Zoology 2010年第4期56卷 437-444页

作者： Willie HENRY Subrata kumar DEY Rakesh varma Sachin THAPA William S PROCUNIER RG. Department of Zoology Darjeeling Government College Darjeeling West Bengal 734101 India School of Biotechnology West Bengal University of TechnologyBF-142 Sector 1Salt Lake City Kolkata 700064 West Bengal India Consultant North Bay Ontario P1B 5W6 Canada

High quality polytene chromosome maps （n=3） of a Himalayan Simuliid Simulium praelargum Datta, 1973 are presented and represent the first cytological description of a taxon found in the feuerborni group, subgenus Nevermannia. Polytene chromosomes one （I） and two （II） are metacentric, chromosome three （III） is submetacentric with the length of each chromosome occupying 37.25 %, 31.36 % and 31.34 % of the total complement length, respectively. Typical simuliid diagnostic intergeneric chromosomal markers are found within the polytene complement of this species. The nucleolar organizer （N.O.） is found at the base of the short arm of chromosome one （IS）, the Ring of Balbiani （R.B.）, double bubble （D.B.） and triad occur in the short arm of chromosome two （IIS）, the Parabalbiani Ring （EB.） and grey band （gb） occur in the long arm of chromosome two （IIL） and the Blister （BL） and Capsule （Ca） occur in the short arm of chromosome three （IIIS）.Terminal bands at the end of IIIS are heterochromatinized and present atypically with respect to other simuliid fauna. Populations studied so far are unique among the Simuliidae in that they exhibit chromosome structural monomorphism. These high resolution polytene chromosome maps will form the basis for future cytological characterization and phylogenetic comparisons amongst members of the feuerborni group

关键词： Black fly Feuerborni group Simulium praelargum Polytene chromosome maps Monomorphism

Spectral narratives of microstructural restyling and their controls on hydrocarbon generation potential from coal

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International Journal of Coal Science & Technology 2023年第3期10卷 167-189页

作者： Tushar Adsul Santanu Ghosh Anwita Ojha Sudip Bhattacharyya Atul kumar varma Coal Geology and Organic Petrology Laboratory Department of Applied GeologyIndian Institute of Technology(Indian School of Mines)DhanbadJharkhand 826004India Department of Geology Mizoram UniversityAizawlMizoram 796004India Specialized Coal Petrography Laboratory Natural Energy ResourcesMission II-BGeological Survey of IndiaDK-6Sector-IlSalt Lake CityKolkataWest Bengal 700091India

The low to medium-rank Tertiary coals from Meghalaya,India,are explored for the first time for their comprehensive micro-structural characterization using the FTIR and Raman ***,results from these coals are compared with the Permian medium and high-rank coals to understand the microstructural restyling during coalification and its controls on hydrocarbon *** coal samples are grouped based on the mean random vitrinite reflectance values to record the transformations in spectral attributes with increasing coal *** aliphatic carbon and the apparent aromaticity respond sharply to the first coalification jump(R:0.50%)during low to medium-rank transition and anchizonal metamorphism of the high-rank ***,the Raman band intensity ratio changes during the first coalification jump but remains invari-able in the medium-rank coals and turns subtle again during the onset of pregraphitization in high-rank coals,revealing a polynomial trend with the coal *** Rock-Eval hydrogen index and genetic potential also decline sharply at the first coalification ***,an attempt to comprehend the coal microstructural controls on the hydrocarbon poten-tial reveals that the Tertiary coals comprise highly reactive aliphatic functionalities in the type I-S kerogen,along with the low paleotemperature(74.59-112.28℃)may signify their potential to generate early-mature ***,the presence of type II-II admixed kerogen,a lesser abundance of reactive moieties,and overall moderate paleotemperature(91.93-142.52℃)of the Permian medium-rank coals may imply their mixed hydrocarbon ***,anchizonal metamorphism,polycondensed aromatic microstructure,and high values of paleotemperature(~334.25 to~366.79℃)of the high-rank coals indicate a negligible potential of producing any hydrocarbons.

关键词： Early mature oil generation Meghalaya high-sulfur coal Type II-S kerogen Microstructural ordering Coalification jump Hydrocarbon generation potential

Finite size effect on dissociation and diffusion of chiral partners in Nambu-Jona-Lasinio model

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Chinese Physics C 2022年第4期46卷 114-122页

作者： Paramita Deb Sabyasachi Ghosh Jai Prakash Santosh kumar Das Raghava varma Department of Physics Indian Institute of Technology BombayPowaiMumbai-400076India Indian Institute of Technology Bhilai GEC CampusSejbaharRaipur-492015ChhattisgarhIndia School of Physical Sciences Indian Institute of Technology GoaPonda-403401GoaIndia

The masses of pion and sigma meson modes,along with their dissociation in the quark medium,provide detailed spectral structures of the chiral *** has been observed in pA and pp systems both at LHC and *** this research,we studied the restoration of chiral symmetry by investigating the finite size effect on the detailed structure of chiral partners in the framework of the Nambu-Jona-Lasinio *** diffusion and conduction have been studied using this dissociation *** is determined that the masses,widths,diffusion coefficients,and conductivities of chiral partners merge at different temperatures in the restoration phase of chiral ***,merging points are shifted to lower temperatures when finite size effect is introduced into the *** strengths of diffusions and conductions are also reduced once the finite size is introduced in the calculations.

关键词： heavy-ion collisions quark gluon plasma effective QCD