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Dynamical behaviors of a constant prey refuge ratio-dependent prey-predator model with Allee and fear effects

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International Journal of biomathematics 2024年第1期17卷 227-250页

作者： Soumitra pal pijush panday Nikhil pal A.K.Misra Joydev Chattopadhyays Department of Mathematics Institute of Science Banaras Hindu University Varanasi 221005India Department of Mathematical and Statistical Sciences University of Alberta EdmontonAB T6G 2G1Canada Department of Mathematics Visva-Bharati Santiniketan 731235India Agricultural and Ecological Research Unit Indian Statistical Institute 203 B.T.RoadKolkata 700108India

In this paper,we consider a nonlinear ratio-dependent prey-predator model with constant prey refuge in the prey *** Allee and fear phenomena are incorporated explicitly in the growth rate of the prey *** qualitative behaviors of the proposed model are investigated around the equilibrium points in *** bifurcation including its direction and stability for the model is also *** observe that fear of predation risk can have both stabilizing and destabilizing effects and induces bubbling phenomenon in the *** is also observed that for a fixed strength of fear,an increase in the Allee parameter makes the system unstable,whereas an increase in prey refuge drives the system toward ***,higher values of both the Allee and prey refuge parameters have negative impacts and the populations go to ***,we explore the variation of densities of the populations in different bi-parameter spaces,where the coexistence equilibrium point remains *** simulations are carried out to explore the dynamical behaviors of the system with the help of MATLAb software.

关键词： predator-prey system Allee effect fear effect prey refuge bifurcation population density

Unraveling the role of dual Ti/Mg metals on the ignition and combustion behavior of HTpb-boron-based fuel

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Defence Technology（防务技术） 2024年第2期32卷 134-143页

作者： Arijit Debnath Yash pal Sri Nithya Mahottamananda Djalal Trache School of Aeronautical Science Hindustan Institute of Technology and ScienceChennai 603103India Department of Aerospace Engineering B S Abdur Rahman Crescent Institute of Science and TechnologyChennai 600048India Energetic Materials Laboratory(EMLab) Teaching and Research Unit of Energetic ProcessesEcole Militaire PolytechniqueBP 17Bordj El-Bahri16046AlgiersAlgeria

Metal additives play an essential role in explosive and propellant formulations. boron(b) is widely used in propellant applications owing to its high energetic content. The addition of b to explosives and propellants increases their energy density, making them more efficient and powerful. Nevertheless, b forms oxide layers on its surface during combustion, slowing down the combustion rate and reducing rocket motor efficiency. To overcome this issue, other metal additives such as aluminum(Al), magnesium(Mg),and titanium(Ti) are revealed to be effective in boosting the combustion rate of propellants. These additives may improve the combustion rate and therefore enhance the rocket motor’s performance. The present study focused on preparing and investigating the ignition and combustion behavior of pure hydroxyl-terminated polybutadiene(HTpb)-b fuel supplemented with nano-titanium and nanomagnesium. The burn rates of HTpb-b fuel samples were evaluated on the opposed flow burner(OFb)under a gaseous oxygen oxidizer, for which the mass flux ranges from 22 kg/(m^(2)·s) to 86 kg/(m^(2)·s). The addition of Ti and Mg exhibited higher regression rates, which were attributed to the improved oxidation reaction of b due to the synergetic metal combustion effect. The possible combustion/oxidation reaction mechanism of b-Mg and b-Ti by heating the fuel samples at 900℃ and 1100℃ was also examined in a Nabertherm burnout furnace under an oxygen atmosphere. The post-combustion products were collected and further subjected to X-ray diffraction(XRD) and field emission scanning electron microscopy(FE-SEM) analyses to inspect the combustion behavior of b-Ti and b-Mg. It has been observed that the b oxide layer at the interface between b-Ti(b-Mg) is removed at lower temperatures, hence facilitating oxygen transfer from the surroundings to the core b. Additionally, Ti and Mg decreased the ignition delay time of b, which improved its combustion performance.

关键词： boron b_(2)O_(3) Opposed flow burner Combustion Magnesium

Comments on the paper: "Dispersion Calculation of Monomode Step-Index Weakly Guiding Fibers" by C. C. Fan et al.,Acta Electronica Sinica, Vol.10, No.1,pp. 8-15, Jan.1982

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电子学报 1983年第4期 111-112页

作者： b.p.pal* and R.Th.KERSTENFraunhofer-Institut fur physikalische Messtechnik, Heidenhofstrasse 8, D-7800 Freiburg, Federal Republic of Germany

In the above publication dispersion calculations have been made for monomode step-index weakly guiding optical fibers. However, as explained below the approach followed in it was. approximate and therefore the conclusions drawn therefrom as regards the accuracy of the two sets of given approximate empirical formulas for prediction of zero dispersion wave-length was. not correct.

关键词： Dispersion Calculation of Monomode Step-Index Weakly Guiding Fibers Fan et al Acta Electronica Sinica by C

Evaluating Ignition and Combustion performance with Al-Metal- Organic Frameworks and Nano-Aluminum in HTpb Fuel

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火炸药学报 2024年第5期47卷 413-421,I0003页

作者： Sri Nithya Mahottamananda Yash pal Yarravarapu Sai Sriram Subha S Djalal Trache Department of Aerospace Engineering B S Abdur Rahman CrescentInstitute of Science and TechnologyChennai-600048India School of Aeronautical Science Hindustan Institute of Technologyand ScienceChennai-603103India Energetic Materials Laboratory(EMLab) Teaching and ResearchUnit of Energetic ProcessesEcole Militaire PolytechniqueBP 17Bordj El-Bahri16046AlgiersAlgeria

Incorporating aluminum metal-organic frameworks(Al-MOFs)as energetic additives for solid fuels presents a promising avenue for enhancing combustion *** study explores the potential benefits of Al-MOF(MIL-53(Al))energetic additive on the combustion performance of hydroxyl-terminated polybutadiene(HTpb)*** HTpb-MOF fuel samples were manufactured using the vacuum-casting technique,followed by a comprehensive evaluation of their ignition and combustion properties using an opposed flow burner(OFb)setup utilizing gaseous oxygen as an *** gauge the effectiveness of Al-MOFs as fuel additives,their impact is compared with that of nano-aluminum(nAl),another traditional additive in HTpb *** results indicate that the addition of 15%(mass fraction)nAl into HTpb resulted in the shortest ignition delay time(136 ms),demonstrating improved ignition performance compared to pure HTpb(273 ms).The incorporation of Al-MOF in HTpb also reduced ignition delay times to 227 ms and 189 ms,***,under high oxidizer mass flux conditions(79—81 kg/(m^(2)s)),HTpb fuel with 15%nAl exhibited a substantial 83.2%increase in regression rate compared to the baseline HTpb fuel,highlighting the positive influence of nAl on combustion *** contrast,HTpb-MOF with a 15%Al-MOF additive showed a 32.7%increase in regression rate compared to pure *** results suggest that HTpb-nAl outperforms HTpb-MOF in terms of regression rates,indicating a more vigorous and rapid burning behavior.

关键词： ignition combustion enhancement MOF HTpb regression rate

Multi-gradient-direction based deep learning model for arecanut disease identification

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CAAI Transactions on Intelligence Technology 2022年第2期7卷 156-166页

作者： S.b.Mallikarjuna palaiahnakote Shivakumara Vijeta Khare M.basavanna Umapada pal b.poornima Department of Computer Science and Engineering Bapuji Institute of Engineering and TechnologyDavanagereAffiliated to Visvesvaraya Theological UniversityBelagaviKarnatakaIndia Faculty of Computer Science and Information Technology University of MalayaKuala LumpurMalaysia Adani Institute of Infrastructure Engineering AhmedabadIndia Department of Computer Science Davanagere UniversityDavanagereKarnatakaIndia Computer Vision and pattern Recognition Unit Indian Statistical InstituteKolkataWest BengalIndia

Arecanut disease identification is a challenging problem in the field of image *** this work,we present a new combination of multi-gradient-direction and deep con-volutional neural networks for arecanut disease identification,namely,rot,split and *** to the effect of the disease,there are chances of losing vital details in the *** enhance the fine details in the images affected by diseases,we explore multi-Sobel directional masks for convolving with the input image,which results in enhanced *** proposed method extracts arecanut as foreground from the enhanced images using Otsu ***,the features are extracted for foreground information for disease identification by exploring the ResNet *** advantage of the proposed approach is that it identifies the diseased images from the healthy arecanut *** results on the dataset of four classes(healthy,rot,split and rot-split)show that the proposed model is superior in terms of classification rate.

关键词： deep learning image analysis pattern recognition

Apoptotic and autophagic death union by Thuja occidentalis homeopathic drug in cervical cancer cells with thujone as the bioactive principle

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Journal of Integrative Medicine 2022年第5期20卷 463-472页

作者： Asmita pal Sucharita Das Soumalee basu Rita Kundu Department of botany University of CalcuttaKolkataWest Bengal 700019India Department of Microbiology University of CalcuttaKolkataWest Bengal 700019India

Objective‘Multi-targeting’drugs can prove fruitful to combat drug-resistance of multifactorial disease—cervical *** study envisioned to reveal if Thuja homeopathic mother tincture(MT)and its bioactive component could combat human papillomavirus(HpV)-16-infected SiHa cervical cancer cells since it is globally acclaimed for HpV-mediated *** Thuja MT was studied for its antiproliferative and antimigratory properties in SiHa cells followed by microscopic determination of reactive oxygen species(ROS)generation by 2’,7’-dichlorodihydrofluorescein diacetate(DCFDA)staining and loss in mitochondrial membrane potential(MMp)by rhodamine(Rh)123 *** and autophagy inductions were studied by acridine orange(AO)ethidium bromide(Eb)staining and immunoblot analyses of marker *** bioactive component of Thuja MT detected by gas chromatography-mass spectrometry was studied for antiproliferative and antimigratory properties along with in silico prediction of its cellular targets by molecular docking and oral drug forming *** Thuja MT showed significant antiproliferative and antimigratory potential in SiHa cells at a 50%inhibitory concentration(IC50)dosage of 17.3μL/*** increase in DCFDA fluorescence and loss in Rh123 fluorescence prove that Thuja MT acted through the burst of ROS and loss in MMp ***/Eb-stained cells under the microscope and immunoblot analyses supported Thuja-induced cellular demise via dual pathways—apoptosis and *** showed cleavage of caspase-3 and poly adenosine diphosphate-ribose polymerase-1(pARp-1)along with upregulation of beclin-1,microtubule-associated protein 1 light chain 3b(LC3b)-II,and p62 ***,the apoptotic cascade followed a caspase-3-dependent pathway supported by pARp-1 cleavage,while autophagic death was beclin-1-dependent and mediated by accumulation of LC3bII and p62 ***,detected as the bioactive principle of Thuja MT showed greater anti-pro

关键词： Thuja Homeopathy Thujone Cervical cancer Apoptosis-autophagy crosstalk

Surface-modified Ag@Ru-p25 for photocatalytic CO_(2) conversion with high selectivity over CH_(4) formation at the solid–gas interface

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Carbon Energy 2024年第1期6卷 182-196页

作者： Chaitanya b.Hiragond Sohag biswas Niket Spowar Junho Lee Eunhee Gong Hwapyong Kim Hong Soo Kim Jin-Woo Jung Chang-Hee Cho bryan M.Wong Su-Il In Department of Energy Science&Engineering Daegu Gyeongbuk Institute of Science and Technology(DGIST)DaeguRepublic of Korea Department of Chemical&Environmental Engineering Materials Science&Engineering ProgramDepartment of ChemistryDepartment of Physics&AstronomyUniversity of California-RiversideRiversideCaliforniaUSA Department of physics and Chemistry Daegu Gyeongbuk Institute of Science and Technology(DGIST)DaeguRepublic of Korea NiceScience Corporation DaeguRepublic of Korea

Systematic optimization of the photocatalyst and investigation of the role of each component is important to maximizing catalytic activity and comprehending the photocatalytic conversion of CO_(2) reduction to solar fuels.A surface-modified Ag@Ru-p25 photocatalyst with H_(2)O_(2) treatment was designed in this study to convert CO_(2) and H_(2)O vapor into highly selective *** doping followed by Ag nanoparticles(Nps)cocatalyst deposition on p25(TiO_(2))enhances visible light absorption and charge separation,whereas H_(2)O_(2) treatment modifies the surface of the photocatalyst with hydroxyl(–OH)groups and promotes CO_(2) ***-resonance transmission electron microscopy,X-ray photoelectron spectroscopy,X-ray absorption near-edge structure,and extended X-ray absorption fine structure techniques were used to analyze the surface and chemical composition of the photocatalyst,while thermogravimetric analysis,CO_(2) adsorption isotherm,and temperature programmed desorption study were performed to examine the significance of H_(2)O_(2) treatment in increasing CO_(2) reduction *** optimized Ag1.0@Ru1.0-p25 photocatalyst performed excellent CO_(2) reduction activity into CO,CH4,and C2H6 with a~95%selectivity of CH4,where the activity was~135 times higher than that of pristine TiO_(2)(p25).For the first time,this work explored the effect of H_(2)O_(2) treatment on the photocatalyst that dramatically increases CO_(2) reduction activity.

关键词： gas-phase CO_(2) reduction H_(2)O_(2) treatment plasmonic nanoparticles solar fuel photocatalyst surface modification

Design of optimum solid oxide membrane electrolysis cells for metals production

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progress in Natural Science:Materials International 2015年第6期25卷 591-594页

作者： Xiaofei Guan Uday b.pal Division of Materials Science and Engineering Boston University Department of Mechanical Engineering Boston University John A.paulson School of Engineering and Applied Sciences Harvard University

Oxide to metal conversion is one of the most energy-intensive steps in the value chain for metals *** oxide membrane(SOM)electrolysis process provides a general route for directly reducing various metal oxides to their respective metals,alloys,or *** of its lower energy use and ability to use inert anode resulting in zero carbon emission,SOM electrolysis process emerges as a promising technology that can replace the state-of-the-art metals production *** this paper,a careful study of the SOM electrolysis process using equivalent DC circuit modeling is performed and correlated to the experimental results.A discussion on relative importance of each resistive element in the circuit and on possible ways of lowering the rate-limiting resistive elements provides a generic guideline for designing optimum SOM electrolysis cells.

关键词： Electrolysis Solid oxide Membranes Metals production Environmentally benign

Thermal properties of Ni–Cr–Si–b–Fe based Interlayer Material and Its Application in TLp bonding of IN 718 Superalloy

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Acta Metallurgica Sinica(English Letters) 2020年第12期33卷 1666-1680页

作者： U.K.Tarai p.S.Robi Sukhomay pal Department of Mechanical Engineering IIT GuwahatiGuwahati 781039India

A new Ni–Cr–Si–b–Fe fi ller material is prepared for transient liquid-phase(TLp)bonding of Inconel 718 superalloy by mechanical alloying *** melting temperature range of the fi ller material and its activation energy of melting are determined by diff erential scanning calorimetry *** activation energy and melting temperature of the alloy powder decrease with increasing milling *** 718 alloy was joined via TLp by using the newly developed fi ller *** eff ect of TLp bonding temperature and time on microstructural evolution and mechanical properties of the joint was *** distinct microstructural regions were observed in the bonding area:isothermal solidifi cation zone consisting of a single-phase solid solution,diff usion aff ected zone consisting of extensive diff usion-induced precipitates of metallic boride,and unaff ected base *** ultimate shear strength and microhardness of the TLp-bonded joint increase with bonding time and temperature.

关键词： Transient liquid-phase(TLp)bonding Kissinger plot Mechanical alloying Inconel 718