检索结果-南通市图书馆

silver Dopant-Induced Effect on structural and Optoelectronic Properties of Cdse Thin Films

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica sinica(English Letters) 2019年第5期32卷 541-549页

作者： Jagdish kaur Ramneek kaur s.k.tripathi PG Department of Physics DAV College Department of Physics Akal University Department of Physics Panjab University

Thin films of Cdse and silver(Ag)-doped Cdse have been prepared on glass substrates by thermal evaporation in argon gas atmosphere. X-ray diffraction pattern indicates the presence of hexagonal structure with preferred orientation along (100) plane. Elemental composition of the thin films has been analyzed using energy dispersive X-ray analysis. scanning electron microscopy has been used to investigate the morphology of the thin films. Transmission electron microscope reveals spherical nature of nanoparticles. A decrease in the band gap due to the formation of band tails in the band gap with increase in Ag doping in Cdse lattice has been observed. Photoluminescence spectra indicate redshift in band edge emission peak with increase in Ag doping in Cdse. Electrical conductivity measurements are also studied, and two types of conduction mechanisms taking part in the transport phenomena are observed. Hall measurements indicate n-type behavior of undoped and Ag-doped Cdse thin films.

关键词： semiconductors Thin films Vapor deposition Electron microscopy Electrical properties

Application of fractal theory in assessing soil aggregates in Indian tropical ecosystems

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2012年第3期23卷 355-364页

作者： s.k.tripathi C.P.kushwaha s.k.Basu Computer science Department Banaras Hindu UniversityVaranasi-221005India Department of Forestry Mizoram UniversityAi-zawl-796009India Centre for Env.sci.&Tech. Banaras Hindu UniversityVaranasi-221005India

soil aggregation varies according to climatic and manage- ment factors, and is difficult to measure because of irregular shapes and sizes of soil aggregates. We applied fractal theory to assess soil aggrega- tion as affected by （1） land use change from forest to savanna, （2） nutri- ent additions in forest, ecotone, and savanna ecosystems, and （3） tillage practice and residue treatments in an agro-ecosystem. We used fractal dimensions nonlinear （D,o,-lin） and linear （Dlin） based on number of ag- gregates （N） and mass of aggregates （M）（the range of values were 2.6-2.89 and 2.694.41, respectively） to capture the variations in the sizes of soil aggregates due to land use and treatments/management in these ecosystems. The variation in the values of non-linear fractal dimension based on mass （DMnon-lin） was smaller in forest and savanna ecosystems with and without nutrient additions, while the variation was wider in agro-ecosystems with different management practices. Linear fractal dimensions based on number （Dr^i,） and mass （DMlin） of aggregates var- ied marginally in these ecosystems and did not capture the variations in soil aggregates well. The variations in non-linear fractal dimension indi- cate that continued nitrogen loading in forest accelerates the formation of macro-aggregates, whereas in savanna the situation was reversed. The values of non-linear fractal dimensions did not show significant change after 6 years of nutrient additions in the ecotone; reflecting a buffering mechanism of this system in soil aggregate formation. On the basis of non-linear fractal dimension values, we conclude that residue retention and minimum tillage are appropriate for proper maintenance of soil ag- gregate stability for sustained crop production in the Indian dry land agro-ecosystems

关键词： soil aggregates fractal tillage practice ecosystem Indian dry tropics

Unsteady peristaltic transport of Maxwell fluid through finite length tube:application to oesophageal swallowing

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2012年第1期33卷 15-24页

作者： s. k. PANDEY D. tripathi Department of Applied Mathematics Institute of Technology Banaras Hindu University Department of Mathematics Indian Institute of Technology Ropar

This paper analytically investigates the unsteady peristaltic transport of the Maxwell fluid in a finite tube. The walls of the tube are subjected to the contraction waves that do not cross the stationary boundaries. The analysis is carried out by a long wavelength approximation in the non-dimensional form. The expressions for the axial and radial velocities are derived. The pressures across the wavelength and the tubelength are also estimated. The reflux phenomenon is discussed, which culminates into the determination of the reflux limit. Mathematical formulations are physically interpreted for the flow of masticated food materials such as bread and white eggs in the oesophagus. It is revealed that the Maxwell fluids are favorable to flow in the oesophagus as compared with the Newtonian fluids. This endorses the experimental finding of Takahashi et al. （Takahashi, T., Ogoshi, H., Miyamoto, k., and Yao, M. L. Viscoelastic properties of commercial plain yoghurts and trial foods for swallowing disorders. Rheology, 27, 169- 172 （1999））. It is further revealed that the relaxation time does not affect the shear stress and the reflux limit. It is found that the pressure peaks are identical in the integral case while different in the non-integral case.

关键词： peristaltic transport Maxwell fluid oesophagus axisymmetric flow reflux

Hydromagnetic thin film flow of Casson fluid in non-Darcy porous medium with Joule dissipation and Navier＇s partial slip

在线全文

学校读者我要写书评

暂无评论

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

An Artificial Neural Network-Based snow Cover Predictive Modeling in the Higher Himalayas

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain science 2014年第4期11卷 825-837页

作者： Bhogendra MIsHRA Nitin k.tripathi Muk s.BABEL Remote sensing and Geographical Information systems Asian Institute of Technology P.O. Box 4 Klong LuangPathumthani 12120 Thailand Water Engineering and Management Asian Institute of Technology P.O. Box 4 Klong Luang Pathumthani 12120 Thailand

With trends indicating increase in temperature and decrease in winter precipitation, a significant negative trend in snow-covered areas has been identified in the last decade in the Himalayas. This requires a quantitative analysis of the snow cover in the higher Himalayas. In this study, a nonlinear autoregressive exogenous model, an artificial neural network （ANN）, was deployed to predict the snow cover in the kaligandaki river basin for the next 30 years. Observed climatic data, and snow covered area was used to train and test the model that captures the gross features of snow under the current climate scenario. The range of the likely effects of climate change on seasonal snow was assessed in the Himalayas using downscaled temperature and precipitation change projection from - HadCM3, a global circulation model to project future climate scenario, under the AIB emission scenario, which describes a future world of very rapid economic growth with balance use between fossil and non-fossil energy sources. The results show that there is a reduction of 9% to 46% of snow cover in different elevation zones during the considered time period, i.e., 2Oll to 2040. The 4700 m to 52oo m elevation zone is the most affected area and the area higher than 5200 m is the least affected. Overall, however, it is clear from the analysis that seasonal snow in the kaligandaki basin is likely to be subject to substantialchanges due to the impact of climate change.

关键词： snow cover kaligandai river Himalayas Artificial neural network Global warming Climatechange

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

在线全文

学校读者我要写书评

暂无评论

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

在线全文

学校读者我要写书评

暂无评论

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

comseedling growth of five tropical dry forest tree species in relation to light and nitrogen gradients

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2014年第3期7卷 250-263页

作者： s.N.tripathi A.s.Raghubanshi Ecosystems Analysis Laboratory Department of BotanyBanaras Hindu UniversityVaranasiUttar Pradesh 221005India Deen Dayal Upadhyaya College University of DelhiShivaji MargKarampuraNew Delhi 110015India Institute of Environment and sustainable Development Banaras Hindu UniversityVaranasiUttar Pradesh 221005India

Aims Increasing anthropogenic nitrogen(N)deposition has been claimed to induce changes in species composition and community dynamics.A greenhouse experiment was conducted to examine the effect of increased N availability on growth and functional attributes of seedlings of five tree species with different life history characteristics under varying *** following questions have been addressed:(i)how do the pioneer and non-pioneer species respond in absolute growth and relative growth rate(RGR)to the interaction of light and nitrogen?(ii)how does the interaction between irradiance and nitrogen availability modulate growth attributes(*** attributes)?(iii)is there any variation in growth responses between leguminous and non-leguminous species along the light and nitrogen gradients?Methods seedlings of five tree species(Acacia catechu,Bridelia retusa,Dalbergia sissoo,Lagerstroemia parviflora and Terminalia arjuna)were subjected to twelve combinations of irradiance and N *** growth traits,including height(HT),basal area(BA),whole plant dry biomass(MD),leaf mass per unit area(LMA),leaf area ratio(LAR),net assimilation rate(NAR),RGR,biomass fractions,root-toshoot ratio(R:s)and leaf nitrogen content,were studied to analyse intra-and inter-specific responses to interacting light and N *** Findings significant interactions for irradiance and N availability for majority of growth attributes indicates that growth and biomass allocation of seedlings were more responsive to N availability under high ***,species responded differentially to N addition and they did not follow successional *** growers(***,a shade-tolerant species and ***,a light demander)exhibited greater response to N enrichment than the fast growers(***,*** and ***).However,N-mediated increment in growth traits was greater in non-legumes(***,*** and ***)compared with that of legumes(*** and D

关键词： tropical dry forest irradiance nitrogen biomass allocation relative growth rate net assimilation rate

stokes flow of micro-polar fluids by peristaltic pumping through tube with slip boundary condition

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2011年第12期32卷 1587-1598页

作者： D.tripathi M.k.CHAUBE P.k.GUPTA Department of Mathematics Indian Institute of Technology Ropar Punjab 140001 India Department of Mathematics Raj Kumar Goel Institute of Technology Ghaziabad 201001 India Department of Applied Mathematics Institute of Technology Banaras Hindu University Varanasi 221005 India

This paper studies the stokes flow of micro-polar fluids by peristaltic pumping through the cylindrical tube under the effect of the slip boundary condition. The motion of the wall is governed by the sinusoidal wave equation. The analytical and numerical solutions for the axial velocity, the micro-polar vector, the stream function, the pressure gradient, the friction force, and the mechanical efficiency are obtained by using the lu- brication theory under the low Reynolds number and long wavelength approximations. The impacts of the emerging parameters, such as the coupling number, the micro-polar parameter, the slip parameter on pumping characteristics, the friction force, the velocity profile, the mechanical efficiency, and the trapping phenomenon are depicted graphically. The numerical results infer that large pressure is required for peristaltic pumping when the coupling number is large, while opposite behaviors are found for the micro-polar parameter and the slip parameter. The size of the trapped bolus reduces with the increase in the coupling number and the micro-polar parameter, whereas it blows up with the increase in the slip parameter.

关键词： stokes flow slip boundary condition mechanical efficiency micro-polarfluid peristaltic pumping trapping