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Applied Mathematics and Mechanics(English Edition) 2017年第11期38卷 1613-1626页

作者： G.S.SETH r.tripathi M.K.MISHrA Department of Applied Mathematics Indian Institute of Technology (India School of Mines) Dhanbad 826004 India

In this paper, the effects of viscous and Ohmic heating and heat genera- tion/absorption on magnetohydrodynamic flow of an electrically conducting Casson thin film fluid over an unsteady horizontal stretching sheet in a non-Darcy porous medium are investigated. The fluid is assumed to slip along the boundary of the sheet. Similar- ity transformation is used to translate the governing partial differential equations into ordinary differential equations. A shooting technique in conjunction with the 4th order runge-Kutta method is used to solve the transformed equations. Computations are car- ried out for velocity and temperature of the fluid thin film along with local skin friction coefficient and local Nusselt number for a range of values of pertinent flow parameters. It is observed that the Casson parameter has the ability to enhance free surface velocity and film thickness, whereas the Forchheimer parameter, which, is responsible for the inertial drag has an adverse effect on the fluid velocity inside the film. The velocity slip along the boundary tends to decrease the fluid velocity. This investigation has various applications in engineering and in practical problems such as very large scale integration （VLSI） of electronic chips and film coating.

关键词： fluid thin film non-Darcy medium velocity slip unsteady stretching sheet,Joule dissipation heat generation/absorption

Hypolipidemic activity of a hydroalcoholic extract of Cyperus scariosus Linn. root in guinea pigs fed with a high cholesterol diet

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Chinese Journal of Natural Medicines 2014年第11期12卷 819-826页

作者： Hiren M.Chawda Divyesh r.Mandavia Pravin H.Parmar Seema N.Baxi Chandrabhanu r.tripathi Pacific Medical College & Hospital Udaipur Rajasthan India Government Medical College Bhavnagar-364001 Gujarat India Analytical Chemistry Division Department of Chemistry Maharaja Krishnakumarsinhji Bhavnagar University Bhavnagar 364002 India

Lipid-lowering and antioxidant activities of a hydroalcoholic extract of Cyperus scariosus Linn. root(HCS) were evaluated in guinea pigs fed with a high cholesterol diet. Serum lipid profile(total cholesterol, triglycerides, LDL-C, VLDL-C, and HDL-C), atherogenic indices and serum enzymes(ALT, AST, ALP, LDH, and CK-MB) were performed in each group at 0 days and at the end of 60 days. Histological study of liver and kidney was done in groups 1, 2, 5, 6 and 7. The total phenolic and flavonoid content in HCS and its antioxidant activity were evaluated by the DPPH assay. Both doses of HCS decreased serum lipid profile and atherogenic indices(P ring, immunosuppressive and antioxidant properties, and mays have value in atherosclerosis prevention. The higher dose of HCS also reduced serum AST, ALP, and LDH levels and rosuvastatin increased AST and ALP levels(P r showed decreased lipid accumulation and improvement in hepatocytes in HCStreated animals. The antioxidant activity of HCS may be responsible for its lipid lowering and cytoprotective action. HCS had significant lipid lowering and antioxidant activity, which; may be due to the phenolic compounds. HCS may be a safe and cost effective alternative to current statin therapy for patients with dyslipidaemia.

关键词： Antioxidant activity Cyperus scariosus Dyslipidemia Statin

Assessment of ecosystem services of rice farms in eastern India

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Ecological Processes 2019年第1期8卷 435-450页

作者： A.K.Nayak Md Shahid A.D.Nayak B.Dhal K.C.Moharana B.Mondal r.tripathi S.D.Mohapatra P.Bhattacharyya N.N.Jambhulkar A.K.Shukla Nuala Fitton Pete Smith H.Pathak ICAr-National rice research Institute CuttackOdisha 753006India Indian Institute of Soil Sciences NabibaghBhopalMadhya PradeshIndia Institute of Biological&Environmental Sciences University of Aberdeen23 St Machar DriveAberdeen AB243UUUK.

Background:rice is a major cereal crop and staple food of eastern India,and most farmers depend solely on rice for their *** farming provides both tangible and non-tangible benefits to ecosystems which need to be maintained and *** benefits are provided through ecosystem services(ES)that include both marketable and ***:In this study,the rice farms in eastern India were valued by quantifying the economic value of the services under conventional method of rice cultivation and the gap of ecosystem services value and farm income per unit area were assessed.A stratified random sampling technique was used in this study for selection of agro-climatic zones,districts,blocks,gram panchayat,and study units(households).Soil sampling was also performed for assessing the regulating services(biocontrol of pests,carbon flow,soil erosion,nitrogen fixation),provisioning services(food and by-products),and supporting services(soil fertility,hydrological flow,nutrient cycling,and soil formation).results:The results indicated that the total economic value of ecosystem services ranged from US$1238 to 1688 ha−1 year−*** marketed(primary production)and non-marketed ecosystem services values ranged from 66–89 to 11–34%of the total,*** of some of the ecosystem services such as cultural services,biodiversity,and gas regulation,which may play a significant role in total ecosystem services,has not been made due to non-availability of data and appropriate methodology for rice *** values of parameters can explain the variability in ecosystem services among the agro-climatic zones in eastern *** of locations based on variability of ecosystem services helps in identifying intervention points for sustaining and improving ecosystem services,while permitting sustainable agro-ecological *** highest total economic gap between ES value and farm income was found in the north central plateau zone(US$

关键词： Ecosystem services rice farming Economic gap Payment for ecosystem services(PES)

A novel slot scheduling technique for duty-cycle based data transmission for wireless sensor network

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Digital Communications and Networks 2022年第3期8卷 351-358页

作者： Yogesh tripathi Arun Prakash rajeev tripathi Department of Electronics and Communication Engineering Motilal Nehru National Institute of Technology AllahabadPrayagraj211004India

The duty cycling process involves turning a radio into an active and dormant state for conserving energy. It is a promising approach for designing routing protocols for a resource-constrained Wireless Sensor Networks (WSNs). In the duty cycle-based WSNs, the network lifetime is improved and the network transmission is increased as compared to conventional routing protocols. In this study, the active period of the duty cycle is divided into slots that can minimize the idle listening problem. The slot scheduling technique helps determine the most efficient node that uses the active period. The proposed routing protocol uses the opportunistic concept to minimize the sender waiting problem. Therefore, the forwarder set will be selected according to the node's residual active time and energy. Further, the optimum routing path is selected to achieve the minimum forwarding delay from the source to the destination. Simulation analysis reveals that the proposed routing scheme outperforms existing schemes in terms of the average transmission delay, energy consumption, and network throughput.

关键词： Duty cycle Energy model Wireless sensor network Slot scheduling technique

A Mathematical Study on Three Layered Oscillatory Blood Flow Through Stenosed Arteries

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Journal of Bionic Engineering 2012年第1期9卷 119-131页

作者： Dharmendra tripathi Department of Mathematics Indian Institute of Technology Ropar Punjab-140001 India

A mathematical model is constructed to examine the characteristics of three layered blood flow through the oscillatory cylindrical tube （stenosed arteries）. The proposed model basically consists three layers of blood （viscous fluids with different viscosities） named as core layer （red blood cells）, intermediate layer （platelets/white blood cells） and peripheral layer （plasma）. The analysis was restricted to propagation of small-amplitude harmonic waves, generated due to blood flow whose wave length is larger compared to the radius of the arterial segment. The impacts of viscosity of fluid in peripheral layer and intermediate layer on the interfaces, average flow rate, mechanical efficiency, trapping and reflux are discussed with the help of numerical and computational results. This model is the generalized form of the preceding models. On the basis of present discussion, it is found that the size of intermediate and peripheral layers reduces in expanded region and enhances in contracted region with the increasing viscosity of fluid in peripheral layer, whereas, opposite effect is observed for viscosity of fluid in intermediate layer. Final conclusion is that the average flow rate and mechanical efficiency increase with the increasing viscosity of fluid in both layers, however, the effects of the viscosity of fluid in both layers on trapping and reflux are opposite to each other.

关键词： mathematical model three layered oscillatory blood flow stenosed arteries mechanical efficiency trapping reflux

A two-dimensional analytical model for channel potential and threshold voltage of short channel dual material gate lightly doped drain MOSFET

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Chinese Physics B 2014年第11期23卷 620-625页

作者： Shweta tripathi Department of Electronics & Communication Engineering Motilal Nehru National Institute of Technology

An analytical model for the channel potential and the threshold voltage of the short channel dual-material-gate lightly doped drain （DMG-LDD） metal-oxide-semiconductor field-effect transistor （MOSFET） is presented using the parabolic approximation method. The proposed model takes into account the effects of the LDD region length, the LDD region doping, the lengths of the gate materials and their respective work functions, along with all the major geometrical parameters of the MOSFET. The impact of the LDD region length, the LDD region doping, and the channel length on the channel potential is studied in detail. Furthermore, the threshold voltage of the device is calculated using the minimum middle channel potential, and the result obtained is compared with the DMG MOSFET threshold voltage to show the improvement in the threshold voltage roll-off. It is shown that the DMG-LDD MOSFET structure alleviates the problem of short channel effects （SCEs） and the drain induced barrier lowering （DIBL） more efficiently. The proposed model is verified by comparing the theoretical results with the simulated data obtained by using the commercially available ATLASTM 2D device simulator.

关键词： dual-material-gate MOSFET lightly doped drain short channel effect threshold voltage

A two-dimensional analytical modeling for channel potential and threshold voltage of short channel triple material symmetrical gate Stack(TMGS) DG-MOSFET

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Chinese Physics B 2016年第10期25卷 518-524页

作者： Shweta tripathi Department of Electronics & Communication Engineering Motilal Nehru National Institute of Technology

In the present work, a two-dimensional（2D） analytical framework of triple material symmetrical gate stack（TMGS）DG-MOSFET is presented in order to subdue the short channel effects. A lightly doped channel along with triple material gate having different work functions and symmetrical gate stack structure, showcases substantial betterment in quashing short channel effects to a good extent. The device functioning amends in terms of improved exemption to threshold voltage roll-off, thereby suppressing the short channel effects. The encroachments of respective device arguments on the threshold voltage of the proposed structure are examined in detail. The significant outcomes are compared with the numerical simulation data obtained by using 2D ATLAS;device simulator to affirm and formalize the proposed device structure.

关键词： triple material symmetrical gate stack(TMGS) DG MOSFET gate stack short channel effect drain induced barrier lowering threshold voltage

A novel approach towards molecular memory device in gate tunable structure of MoS_(2)-graphene

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Nano research 2021年第1期14卷 177-184页

作者： rahul tripathi Abha Misra Department of Instrumentation and Applied Physics Indian Institute of Sciencey BangaloreKarnataka 560012India

Molecular interaction in two-dimensional(2D)van der Waals(vdW)interfaces has drawn tremendous attention for extraordinary materials *** sensing characteristics of molecular interaction has been exploited extensively to reach the detection limit to a few parts-per-billion(ppb)of molecules and far less attention is given to the evolution of persistent current state due to the molecular *** study focuses on molecular memory operation of MoS_(2)-graphene heterostructure based field effect *** resistance state of the device due to the external perturbation of molecules is tuned to get a nearly relaxation free current state at much lower molecular concentration of 10 ppb tofacilitate non-volatile memory features for molecular memory *** ultrafast switching operation in milli-second order is achieved at room temperature for the fastest recovery obtained sofar in any molecular *** process is co-controlled both by molecular as well as external charge density.

关键词： MoS_(2) graphene field effect transistor molecular memory trap charges

Thermal Stability of Supercapacitor for Hybrid Energy Storage System in Lightweight Electric Vehicles:Simulation and Experiments

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Journal of Modern Power Systems and Clean Energy 2022年第1期10卷 170-178页

作者： Vima Mali Brijesh tripathi Department of Electrical Engineering/Solar Energy Pandit Deendayal Petroleum UniversityGandhinagarIndia Department of Science Pandit Deendayal Petroleum UniversityGandhinagarIndia

recent research findings indicate that the non-monotonic consumption of energy from lithium-ion(Li-ion)batteries results in a higher heat generation in electrical energy storage *** peak demands,a higher heat generation due to high discharging current increases the temperature from 80℃ to 120℃,thereby resulting in thermal *** address peak demands,an additional electrical energy storage component,namely supercapacitor(SC),is being investigated by various research *** paper provides insights into the capability of SCs in lightweight electric vehicles(EVs)to address peak demands using the worldwide harmonized light-duty driving test cycle(WLTC)driving profile in MATLAB/Simulink at different ambient *** results indicate that temperature imposes a more prominent effect on Li-ion batteries compared with SCs under peak demand *** effect of the discharging rate limit on the Li-ion battery current is *** result shows that SCs can accommodate the peak demands for a low discharging current limit on the battery,thereby reducing heat *** impedance spectroscopy and cyclic voltammetry are performed on SCs to analyze their thermal performance at different temperatures ranging from 0℃ to 75℃ under different bias values of-0.6,0,0.6,and 1 V,*** results indicate a higher specific capacitance of the SC at an optimum operation temperature of 25℃ for the studied *** study shows that the hybrid combination of the Li-ion battery and SC for a lightweight EV can address peak demands by reducing thermal stress on the Li-ion battery and increasing the driving range.

关键词： Electric vehicle lithium-ion battery supercapacitor thermal stability

rainforests north of the Tropic of Cancer: Physiognomy, floristics and diversity in ‘lowland rainforests’ of Meghalaya, India

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Plant Diversity 2017年第1期39卷 20-36页

作者： Uma Shankar Amit Kumar.tripathi Department of Botany North-Eastern Hill University Shillong 793 022 India

The lowland rainforests of Meghalaya, India represent the westernmost limit of the rainforests north of the Tropic of Cancer. These forests, on the Shillong plateau, are akin to Whitmore's ‘tropical lowland evergreen rainforest' formation and exhibit striking similarities and conspicuous differences with the equatorial rainforests in Asia-Pacific as well as tropical seasonal rainforests in southwestern China near the Tropic of Cancer. We found these common attributes of the rainforests in Meghalaya: familial composition with predominance of Euphorbiaceae, Lauraceae, Meliaceae, Moraceae, Myrsiticaceae,Myrtaceae and rubiaceae; deciduousness in evergreen physiognomy; dominance of mega-and mesophanerophytic life-forms; abundance of species with low frequency of occurrence(rare and aggregated species); low proportional abundance of the abundant species; and truncated lognormal abundance distribution. The levels of stand density and stand basal area were comparable with seasonal rainforests in southwestern China, but were lower than equatorial rainforests. Tropical Asian species predominated flora, commanding 95% of the abundance. The differences include overall low stature(height) of the forest, inconspicuous stratification in canopy, fewer species and individuals of liana, thicker understory,higher proportion of rare species, absence of locally endemic species and relatively greater dominance of Fagaceae and Theaceae. The richness of species per hectare(S) was considerably lower at higher latitudes in Meghalaya than in equatorial rainforests, but was comparable with seasonal rainforests. Shannon's diversity index(H’=4.40 nats for ≥10 cm gbh and 4.25 nats for ≥30 cm gbh) was lower on higher latitudes in Meghalaya in comparison to species-rich equatorial rainforests, but it was the highest among all lowland rainforests near the Tropic of Cancer.

关键词： Lowland rainforest Forest structure Floristics Phytosociology Species richness Life-form spectrum