检索结果-南通市图书馆

THE EFFECT OF MAGNETIC FIELDS ON LOW FREQUENCY OSCILLATING NATURAL CONVECTION WITH PRESSURE GRADIENT

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2003年第3期24卷 274-283页

作者： G.C.Sharma Madhu Jain Mahesh chandra School of Mathematical Sciences Institute of Basic ScienceSchool of Mathematical SciencesInstitute of Basic ScienceSchool of Mathematical SciencesInstitute of Basic Science KhandariAgra-282002IndiaKhandariAgra-282002IndiaKhandariAgra-282002India

The oscillating natural convection in the presence of transverse magnetic field with time depending pressure gradient is studied. The analysis of the problem is carried out by assuming that the fluid is flowing in a parallel plate configuration. The emphasis is on low frequency oscillating convective flows induced by g-jitter associated with micro gravity because of their importance to the space processing materials. A general solution for an oscillating flow in the presence of transverse magnetic field is carried out. Some special cases of the oscillating flow and its response to an applied magnetic field are performed. It was observed that the behavior of oscillating free convective flows depends on frequency, amplitude of the driving buoyancy forces, temperature gradient,magnetic field and the electric conditions of the channel walls. In the absence of magnetic field, buoyancy force plays a predominant role in driving the oscillatory flow pattern, and velocity magnitude is also affected by temperature gradients. To suppress the oscillating flow external magnetic field can be used. It is also found that the reduction of the velocity is inversely proportional to the square of the applied magnetic field with conducting wall but directly proportional to the inverse of the magnetic field with insulating wall. Detailed calculations and computational results are also carried out to depict the real situation.

关键词： convection g- jitter acceleration buoyancy force magnetic field pressure gradient

Sliding Mode Control of Coupled Tank Systems Using Conditional Integrators

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2020年第1期7卷 118-125页

作者： Sankata Bhanjan Prusty Sridhar Seshagiri Umesh chandra Pati Kamala Kanta Mahapatra Department of Electronics and Communication Engineering Madanapalle Institute of Technology and ScienceMadanapalleAndhra Pradesh 517325India Department of Electrical and Computer Engineering San Diego State UniversitySan DiegoCA 92182 USA Department of Electronics and Communication Engineering National Institute of TechnologyRourkelaOdisha 769008India

For the problem of set point regulation of the liquid level in coupled tank systems, we present a continuous sliding mode control(SMC) with a "conditional integrator", which only provides integral action inside the boundary layer. For a special choice of the controller parameters, our design can be viewed as a PID controller with anti-windup and achieves robust *** proposed controller recovers the transient response performance without control chattering. Both full-state feedback as well as output-feedback designs are presented in this work. Our output-feedback design uses a high-gain observer(HGO) which recovers the performance of a state-feedback design where plant parameters are assumed to be known. We consider both interacting as well as non-interacting tanks and analytical results for stability and transient performance are presented in both the cases. The proposed controller continuous SMC with conditional integrators(CSMCCI) provides superior results in terms of the performance measures as well as performance indices than ideal SMC, continuous SMC(CSMC) and continuous SMC with conventional integrator(CSMCI). Experimental results demonstrate good tracking performance in spite of unmodeled dynamics and disturbances.

关键词： Conditional integrator coupled tank system LabVIEW sliding mode control

Community Responses to Mountain Tourism:A Case in Bhyundar Valley,Indian Himalaya

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2009年第4期6卷 394-404页

作者： Ram Babu Singh Suraj Mal chandra Prakash Kala Department of Geography Delhi School of EconomicsUniversity of Delhi Department of Geography Shaheed Bhagat Singh CollegeUniversity of Delhi Ecosystem and Environment Management Division Indian Institute of Forests Management

Tourism industry has become an important part of Indian economy,and tourism development has been,however,concentrated to a few areas. Accumulation of tourism activities has reached the critical stage in most of the tourism centers,which pose serious threats to the natural environment. The Bhyundar Valley of Nanda Devi Biosphere Reserve (NDBR) in Uttarakhand State of the Indian Himalaya is a burning example of such problems. Land use/cover changes,deforestation and accumulation of garbage are some of the negative impacts of unregulated tourism in the valley. Unsustainable activities of tourists and villagers in the valley make such problems very severe. To deal with the ongoing problems and ensure community involvement in tourism management and environmental conservation,the Biosphere Reserve Authority introduced ecotourism in the form of Eco Development Committees (EDCs) in the Bhyundar Valley. Study reveals that many problems associated with tourism have been minimized to some extent with the help of EDCs but few are still prevailing in valley. However,the existing attempts to conserve the valley from the negative effects of tourism are inadequate and modifications are needed in the current initiatives.

关键词： Mountain tourism Land use change Community response Eco development committee Environmental management

Understanding gaseous reduction in swine manure resulting from nanoparticle treatments under anaerobic storage conditions

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2019年第8期31卷 179-191页

作者： Niloy chandra Sarker Md Borhan Ann-Marie Fortuna Shafiqur Rahman Agricultural and Biosystems Engineering Department North Dakota State University USDA-ARS Grazinglands Research Laboratory

Manure is an impending source of carbon(C), sulfur(S) and water(H_2 O). Consequently,microbial populations utilize these constituents to produce methane(CH4), carbon dioxide(CO_2), greenhouse gases(GHGs), and hydrogen sulfide(H_2 S). Application of nanoparticles(NPs) to stored manure is an emerging GHG mitigation technique. In this study, two NPs: nano zinc oxide(nZnO) and nano silver(nAg) were tested in swine manure stored under anaerobic conditions to determine their effectiveness in mitigating gaseous emissions and total gas production. The biological sources of gas production, i.e., microbial populations were characterized via Quantitative Polymerase Chain Reaction(qPCR) analysis. Additionally, pH, redox, and VFAs were determined using standard methods. Each treatment of the experiment was replicated three times and NPs were applied at a dose of 3 g/L of manure. Also, headspace gas from all treatment replicates were analyzed for CH_4 and CO_2 gas concentrations using an SRI-8610 Gas Chromatograph and H_2 S concentrations were measured using a Jerome 631 X meter. Nanoparticles tested in this study reduced the cumulative gas volume by 16%–79% compared to the control. Among the NPs tested, only nZnO consistently reduced GHG concentrations by 37%–97%. Reductions in H_2 S concentrations ranged from 87% to97%. Gaseous reductions were likely due to decreases in the activity and numbers of specific gas producing methanogenic archaea and sulfate reducing bacterial(SRB)species.

关键词： Swine manure Nanoparticles Greenhouse gas Methanogen Sulfate reducing bacteria(SRB)

Study of Non-Pharmacological Interventions on COVID-19 Spread

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2020年第12期125卷 967-990页

作者： Avaneesh Singh Saroj Kumar chandra Manish Kumar Bajpai PDPM Indian Institute of Information Technology Design and ManufacturingJabalpur482005India

COVID-19 disease has emerged as one of the life threatening threat to the society.A novel beta coronavirus causes *** began as unidentified pneumonia of unknown etiology in Wuhan City,Hubei province in China emerged in December *** vaccine has been produced till *** models are used to study the impact of different measures used to decrease *** models have been designed to estimate the numbers of spreaders in different scenarios in the present *** the present manuscript,three different mathematical models have been proposed with different scenarios,such as screening,quarantine,andNPIs,to estimate the number of virus *** analysis shows that the numbers of COVID-19 patients will be more without screening the peoples coming from other *** every people suffering fromCOVID-19 disease are *** screening and quarantine with NPIs have been implemented to study their impact on the *** has been found that NPI measures can reduce the number of *** NPI measures reduce the spread function’s growth and provide decision makers more time to prepare with in dealing with the disease.

关键词： Coronavirus COVID-19 mathematical modelling epidemic

Reproductive biology of Cornus capitata Wall. ex Roxb.: a native species in East Asia

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 Forestry Research 2019年第6期30卷 2039-2050页

作者： Vinod Prasad Khanduri Arun Sukumaran chandra Mohan Sharma College of Forestry VCSG Uttarakhand University of Horticulture and Forestry

The reproductive biology of Cornus capitata was studied in detail from June 2014 to October 2015 in Tehri Garhwal, Uttarakhand, western Himalaya, India and elucidated floral morphology, confirming autogamy, geitonogamy, and xenogamy. A new inflorescence ball formed each year with developing fruits that were initiated the previous year; thus reproduction is a continuous cycle. The total pollen production within a tree ranged between 4.0 × 10~7 and 9.3 × 10~7. Anthesis peaked between 08:00 and 10:00. There was significant effect of micro-environmental condition on anthesis(F = 243.8, p = 3.01). A significant positive relationship between the number of lateral shoots and total inflorescence showed that the inflorescence production in C. capitate depends largely on the number of lateral shoots. Time and concentration of various solutions significantly affected pollen germination(time: F = 5.39, p = 0.002; concentration: F = 1.40,p = 0.234). Anthophora bees and thrips were observed as the main pollinators. There was a significant difference in seed set between natural and obligate self-pollination(t = 11.84, p = 1.99). Significant effect was also observed on fruit size(t = 8.88, p = 2.09) between open and shaded conditions. SEM micrographs of pollen grains showed that the shape of dehydrated pollen grains differed greatly due to variations in the rate of dehydration among pollen grains within the anther. Seed germination was observed only in quality seed derived from open pollination, supporting xenogamy in C. capitata. Findings of the present study will be of immense value in formulating effective conservation measures for the species in wild habitats.

关键词： Floral development Pollen production Pollination Pollinators Reproductive success SEM analysis

Flow of a micropolar fluid in a micro-channel under the action of an alternating electric field: Estimates of flow in bio-fluidic devices

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2015年第3期27卷 350-358页

作者： MISRA J.C. chandra S. HERWIG H. Centre for Healthcare Science and Technology Indian Institute of Engineering Science and Technology Department of Physics Sabang S. K. Mahavidyalaya Vidyasagar University Institute of Thermo-Fluid Dynamics Technische Universitat Hamburg-Harburg

The paper is devoted to a study of the electro-osmotic flow of a micropolar bio-fluid, when the flow takes place between two plates that are in a state of periodic vibrations. Considering blood as a micropolar fluid, it is found that the amplitude of oscillation of the microparticles of blood increases when the micropolar effect is pronounced more and more and that a rise in DebyeHtickel parameter enhances both the velocity and microrotation gradient. The results provide guidelines for the improvement of design of bio-sensing and micro-fluidic devices. The study leads to the conclusion that electrical double layers formed in the vicinity of the wall can significantly alter the flow dynamics of physiological fluids in micro-bio-fluidic devices.

关键词： microrotation Electro-osmotic flow Debye-Hiickel parameter micropolar fluid

Chemical characteristics of trace metals in PM10 and their concentrated weighted trajectory analysis at Central Delhi,India

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2017年第5期29卷 184-196页

作者： Subhash chandra Monika J.Kulshrestha Ruchi Singh Nahar Singh CSIR-National Physical Laboratory New Delhi 110012 India. Academy of Scientific and Innovative Research (AcSIR) CSIR - National Physical Laboratory (CSIR-NPL) Campus New Delhi 110012 India Present address: Shriram Institute for Industrial Research Delhi 110007 India.

Trace metals associated with PM10 aerosols and their variation during day and nighttime as well as during different seasons have been studied for the year 2012. PCA analysis suggested5 PCs,which accounted for 86.8% cumulative variance. PC1 accounted for 30% with a significant loading of metals of anthropogenic origin,while PC2 showed 28% variance with the loading of metals of crustal origin. These trace metals showed seasonal distinct day and night time characteristics. The concentrations of Cu,Pb,and Cd were found to be higher during nighttime in all the seasons. Only Fe was observed with significantly higher mean concentrations during daytime of all seasons except monsoon. The highest mean values of Cu,Cd,Zn,and Pb during post-monsoon might be attributed to winds advection over the regions of waste/biomass burning and industrial activities in Punjab and Haryana ***,concentration weighted trajectory analysis suggested that metals of crustal origin were contributed by long-range transport while metals of anthropogenic and industrial activities were contributed by regional/local source regions.

关键词： Trace metals Potential source regions Backward trajectory Principal component analysis

Emission profiling of diesel and gasoline cars at a city traffic junction

在线全文

学校读者我要写书评

暂无评论

Particuology 2015年第1期13卷 186-193页

作者： Avinash Kumar Agarwal Tarun Gupta Prakhar Bothra Pravesh chandra Shukla Engine Research Laboratory Department of Mechanical EngineeringIndian Institute of Technology Kanpur Department of Civil Engineering Indian Institute of Technology Kanpur

In congested urban roads, cars must stop at intersections because of city traffic lights. As a result, pedestri- ans and traffic police personnel are exposed to pollutants emanating from the tailpipe of various vehicles at such city trafficjunctions. In this study, various gasoline- and diesel-fueled cars complying with differ- ent emission standards were tested for their emissions in simulated city traffic junction conditions. The engine exhaust from these cars was subjected to physicochemical characterization at different engine speeds under no-load conditions. These engine conditions were chosen because the cars idle at differ- ent engine speeds at a city traffic junction. Gravimetric and real-time measurements were performed for the tailpipe exhaust sampled from these vehicles. Exhaust particles were collected on 47 mm diameter quartz filter papers and subjected to gravimetric analysis for determining the total particulate mass （TPM） and trace metals while the engines were operated at two different engine idling speeds, 1500 rpm （representing low idling） and 2500 rpm （representing high idling）. At similar engine operating condi- tions, TPM and trace metals were lower for the exhaust from gasoline engines compared to the exhaust from diesel engines. Real-time measurements were performed for particle-bound poly-aromatic hydro- carbons （PAHs）, particle number and size distribution, regulated gaseous emissions and smoke opacity of the exhaust at four different engine speeds, 1500, 2000, 2500, and 3000 rpm. Particle-bound PAHs showed a decreasing trend for the vehicles that complied with stricter vehicular emission standards. Higher particle peak number concentrations were observed for diesel exhausts compared to the results for gasoline exhaust. Regulated gaseous emissions were also comoared.

关键词： Traffic junctions Traffic stop emissions Particle number emission Particle mass emissions Diesel and gasoline fueled cars