检索结果-南通市图书馆

Power and Cross-Spectra for the Turbulent Atmospheric Motion and Transports in the Domain of Wave Number Frequency Space: Theoretical Aspects

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 1994年第4期11卷 491-498页

作者： M. Y. Totagi Indian Institute of Tropical Meteorology Pashan Pune-8 India

The study of large-scale atmospheric turbulence and transport processes is of vital importance in the general circulation of the atmosphere. The governing equations of the power and cross-spectra for the atmospheric motion and transports in the domain of wave number frequency space have been derived. The contributions of the nonlinear interactions of the atmospheric waves in velocity and temperature fields to the conversion of kinetic and potential energies and to the meridional transports of angular momentum and sensible heat in the atmosphere have been discussed.

关键词： Spectral analysis Fourier transform Power and cross-spectra Atmospheric turbulence Wave number frequency space Kinetic and potential energies Transports of angular momentum and sensible heat

Large inter annual variation in air quality during the annual festival ‘Diwali' in an Indian megacity

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2016年第5期28卷 265-272页

作者： Neha Parkhi Dilip Chate Sachin D.Ghude Sunil Peshin Anoop Mahajan Reka Srinivas Divya Surendran Kaushar Ali Siddhartha Singh Hanumant Trimbake Gufran Beig Indian Institute of Tropical Meteorology Pashan Pune India India Meteorological Department New Delhi India

A network of air quality and weather monitoring stations was established under the System of Air Quality Forecasting and Research（SAFAR） project in Delhi. We report observations of ozone（O_3）, nitrogen oxides（NO_x）, carbon monoxide（CO） and particulate matter（PM_2.5and PM_（10）） before, during and after the Diwali in two consecutive years, i.e., November 2010 and October 2011. The Diwali days are characterised by large firework displays throughout India. The observations show that the background concentrations of particulate matter are between 5 and 10 times the permissible limits in Europe and the United States. During the Diwali-2010, the highest observed PM_（10） and PM_2.5mass concentration is as high as2070 μg/m^3 and 1620 μg/m3, respectively（24 hr mean）, which was about 20 and 27 times to National Ambient Air Quality Standards（NAAQS）. For Diwali-2011, the increase in PM_（10） and PM_2.5mass concentrations was much less with their peaks of 600 and of 390 μg/m^3 respectively, as compared to the background concentrations. Contrary to previous reports,firework display was not found to strongly influence the NO_x, and O_3 mixing ratios, with the increase within the observed variability in the background. CO mixing ratios showed an increase. We show that the large difference in 2010 and 2011 pollutant concentrations is controlled by weather parameters.

关键词： Particulate pollution Fireworks Trace gases System of Air Quality Forecasting and Research(SAFAR) Air quality Diwali

LARGE-SCALE FEATURES OF THE INDIAN SUMMER MONSOON RAINFALL AND THEIR ASSOCIATION WITH SOME OCEANIC AND ATMOSPHERIC VARIABLES

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 1988年第4期5卷 499-513页

作者： K. D. Prasad,S. V. Singh Indian Institute of Propical Meteorology pashan Pune-411008 Indian Institute of Propical Meteorology pashan Pune-411008

The summer monsoon rainfall totals for 31 meteorological subdivisions of India for the years 1901-1980 are analysed. The analysis reveals that four leading eigenvectors (EVs) are significant and account for 65% of the total *** spatial pattern of the first EV exhibits in phase fluctuations over almost the whole India. The large coefficients of this vector can be considered as representative of the conditions of large-scale flood and drought over the country. The second pattern reveals the fluctuations mostly over the North Indian region (north of 20° latitude) probably in association with the Western Disturbances. The third pattern indicates fluctuations over the North-West and the North-East India in opposite phase and the fourth pattern exhibits the characteristic features of fluctuations associated with 'break'. The spectral analysis of the coefficients of these EVs revealed quasi-periodicities of 2-5 *** the basis of examination of the elements of these EVs the country has been divide

关键词： EVI EI over LARGE-SCALE FEATURES OF THE INDIAN SUMMER MONSOON RAINFALL AND THEIR ASSOCIATION WITH SOME OCEANIC AND ATMOSPHERIC VARIABLES Nino

Diurnal Variation of Southwest Monsoon Rainfall at Indian Stations

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 1994年第1期11卷 111-120页

作者： J.M. Pathan(Indian Institute of Tropical Meteorology, pashan, Pune-411008, India) 1. Indian Institute of Tropical Meteorology Pashan 411008 Pune India

The paper presents the patterns of rainfall behavior brought out by the diagrams depicting the diurnal variation of SW monsoon rainfall at selected indian stations. The stations in different geographical locations are found to exhibit different patterns of diurnal variation of rainfall. In general, coastal and island stations show enhanced rainfall from midnight to morning hours and below average rainfall during day time. Many inland stations show rainfall maximum towards afternoon/evening hours. Some hill stations show the same behavior as inland stations. However, at the heavy rainfall station of Cherrapunjee, the rainfall behavior is similar to that at the coastal stations. Possible physical mechanisms responsible for the diurnal variation of rainfall at stations under different categories, are briefly discussed. Harmonic analysis of hourly SW monsoon rainfall data of 33 stations show that for 19 stations, the first harmonic accounts for more than 50% of the variance of the rainfall series. These consist of (i) inland stations for which the maximum of the first harmonic is reached between 16 hours IST and midnight, and (n) coastal/island stations for which the maximum is seen between 03 and 07 hours IST. At most of the coastal and island stations, the first harmonic alone accounts for 75% orb more of the variance. For the heavy rainfall station of Cherrapunjee, the first harmonic which attains its maximum at 3.8 hours IST (-4.4 hours LT), is able to account for 96% of the variance of the rainfall series. It is hoped that the information contained in this paper about the pattern of diurnal modulation of monsoon rainfall may serve as background material to monsoon precipitation climatology.

关键词： Diurnal variation Monsoon rainfall Indian stations Harmonic analysis Hourly rainfall

An experimental and numerical approach-characterisation of power cartridge for water-jet application

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2018年第6期14卷 683-690页

作者： Bhupesh Ambadas Parate Sunil Chandel Himanshu Shekhar Armament Research&Development Establishment(ARDE) Dr.Homi Bhabha RoadPashanPune 411021India Defence Institute of Advanced Technology(DIAT) Giri NagarKhadakwasalaPune411025India High Energy Material Research Laboratory(HEMRL) SutarwadiPashanPune411021India

Power Cartridges are pyrotechnic devices where hot combustion gases utilized to do mechanical work for disruption of suspected Improvised Explosive Devices(IEDs). It plays a vital role either in destroying the suspicious object or making them non-functional by generating the gas pressure on burning of propellant against the water column inside the barrel, Present work is focused on characterisation,numerical solution such as deformation; strain; stress using FEM(Finite Element Method), design qualification, performance and evaluation of power cartridge for disruptor application. Experimental trials for pressure-time(P-t) measurement in closed vessel(CV), various electrical parameters like all fire current(AFC), no fire current(NFC) and ignition delay have been measured. Further, mechanical properties for brass material have been determined. An attempt has been made to characterise the power cartridge by FEM and carrying out the experiments for water-jet application.

关键词： All fire current Closed vessel Booster Characterisation Disruptor Finite element method Ignition delay Maximum pressure No fire current Power cartridge Propellant&water-jet

Observations of NO_2 and O_3 during Thunderstorm Activity Using Visible Spectroscopy

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 1996年第3期13卷 359-374页

作者： D.B.Jadhav A.L.Londhe S.Bose Indian Institute of Tropical Meteorology Dr.Homi Bhabha MargPashanPune-411008MaharashtraIndiaIndian Institute of Tropical MeteorologyDr.Homi Bhabha MargPashanPune-411008MaharashtraIndiaIndian Institute of Tropical MeteorologyDr.Homi Bhabha MargPashanPune-411008MaharashtraIndia

Simultaneous observations for the total column densities of NO2,O3 and H2O were carried on using the portable Spectrometer (438-450 nm and 400-450 nm) and the visible Spectrometer (544.4-628 nm) during premonsoon thunderstorms and embedded hail storm activity at Pune (18°32'N & 73°51'E),*** observations confirm the fact that there is an increase in O3 and NO2 column densities during *** increase in O3 was observed following onset of thunderstorm,while the increase in NO2 was observed only after the thunder flashes *** implies that the production mechanisms for O3 and NO2 in thunderstorm are *** observed column density of NO,value (1 to 3×1017molecules cm-2) during thunderstorm activity is 10 to 30 times higher than the value (1×10th molecules cm-2) of a normal day total column *** spectrometric observations and observations of thunder flashes by electric field meter showed that 6.4×1025molecules/flash of NO2 are *** increased to-oil column density of ozone during thunderstorm period is 1.2 times higher than normal (clear) day ozone *** multiple scattering in the clouds is estimated from H2O and O2 absorption bands in the visible spectral region Considering this effect the calculated amount of ozone added in the global atmosphere due to thunderstorm activity is 0.26 to 0 52 DU,and the annual production of ozone due to thunderstorm activity is of the order of 4.02×10 molecules/year The annual NO2 production may be of the order of 2.02×1035molecules/year.

关键词： Visible Spectroscopy Thunderstorm Ozone production NO2 production Atmospheric electricity Lightning flashes. Multiple scattering factor

Enhanced acetone sensing performance of nanostructured Sm2O3 doped SnO2 thick films

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2017年第8期35卷 813-823页

作者： F.I.Shaikh L.P.Chikhale J.Y.Patil I.S.Mulla S.S.Suryavanshi School of Physical Sciences Solapur University Solapur 413255 (M.S.) lndia Council of Scientific and Industrial Research Pashan Pune 411008 India

In the present work, we synthesized Sm2O3 doped SnO2 in order to prepare a selective acetone sensor with fast response, quick recovery and good repeatability. Pure as well as 2 mol.%, 4 mol.%, 6 mol.% and 8 mol.% Sm2O3 doped SnO2 nanostructured samples were synthesized by using a co-precipitation method. The characterization of the samples was done by thermogravimetric and differential thermo-gravimetric analysis（TG-DTA）, X-ray diffraction（XRD）, field emission gun-scanning electron microscopy（FEG-SEM）, energy dispersive analysis by X-rays（EDAX）, high resolution scanning electron microscopy（HR-TEM）, selected area X-ray diffraction（SAED）, Brunauer-Emmet-Teller（BET） and ultraviolet-visible-near infrared（UV-Vis-NIR） spectroscopy techniques. The gas response studies of liquid petroleum gas, ammonia, ethanol and acetone vapor were carried out. The results showed that Sm doping systematically lowered operating temperature and enhanced the gas response and selectivity for acetone. The response and recovery time for 6 mol.% Sm2O3 doped SnO2 thick film at the operating temperature of 250 °C were 15 and 24 s, respectively.

关键词： tin oxide samarium oxide screen printing thick film acetone sensor rare earths

Multiyear Observations of Deposition-Mode Ice Nucleating Particles at Two High-Altitude Stations in India

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2017年第12期34卷 1437-1446页

作者： Sandeep D.WAGH Baban NAGARE Sanjay D.MORE P.Pradeep KUMAR Department of Atmospheric and Space Sciences Savitribai Phule Pune University Indian Institute of Tropical Meteorology pashan Skymet Weather Services Pvt Ltd.

Ice nucleating particle(INP) measurements were made at two high-altitude stations in India. Aerosols collected on filter paper at Girawali Observatory, Inter University Center for Astronomy & Astrophysics(IGO), and at the Radio Astronomy Center, Ooty(RAC), were activated in deposition mode using a thermal gradient diffusion chamber to determine the INP concentrations. The measurement campaigns at IGO were conducted during 2011, 2013 and 2014, and at RAC during 2013 and 2014. When the aerosol samples were exposed to an ice supersaturation of between 5% and 23% in the temperature range-17.6?C to-22?C, the maximum INP number concentration at IGO and RAC was 1.0 L-1and 1.6 L-1, respectively.A maximum correlation coefficient of 0.76 was observed between the INP number concentration and ice supersaturation. The airmass trajectories analyzed for the measurement campaigns showed that the Arabian Desert and arid regions were the main INP contributors. Elemental analysis of particles showed the presence of Na, Cl, Si, Al, Fe, Cu, Co, Cd, S, Mn and K, as well as some rare-Earth elements like Mo, Ru, La, Ce, V and Zr. When aerosols in the size range 0.5–20 μm were considered, the fraction that acted as INPs was 1 : 104to 1 : 106at IGO, and 1 : 103to 1 : 104at RAC. The higher ratio of INPs to aerosols at RAC than IGO may be attributable to the presence of rare-Earth elements observed in the aerosol samples at RAC, which were absent at IGO.

关键词： ice nuclei diffusion chamber aerosol high-altitude observation

Self-assembled vertically aligned gold nanorod super-lattices for ultra-high sensitive detection of molecules

在线全文

学校读者我要写书评

暂无评论

Nano Research 2015年第3期8卷 907-919页

作者： Amey Apte Prashant Bhaskar Raja Das Smita Chaturvedi PankajPoddar Sulabha Kulkarni Indian Institute of Science Education and Research (IISER) Homi Bhabha Road Pashan Pune - 411008 India Physical and Materials Chemistry Division CSIR-National Chemical Laboratory Pashan Pune - 411008 India Academy of Scientific and Innovative Research (AcSIR) Anusandhan Bhavan 2 Raft Marg New Delhi - 10000 I India

We show that self-assembled vertically aligned gold nanorod （VA-GNRs） superlattices can serve as probes or substrates for ultra-high sensitive detection of various molecules. D-glucose and 2,4,6-trinitrotoluene （TNT） have been chosen as model systems due to their very low Raman cross-sections （5.6× 10-30 ***-1 for D-glucose and 4.9 × 10-31 ***-1 for TNT） to show that the VA-GNR superlattice assembly offers as low as yoctomole sensitivity. Our experiment on mixed samples of bovine serum albumin （BSA） and D-glucose solutions demonstrate sensitivity for the latter, and the possible extension to real samples. Self-assembled superlattices of VA-GNRs were achieved on a silicon wafer by depositing a drop of solvent containing the GNRs and subsequent solvent evaporation in ambient conditions. An additional advantage of the VA-GNR monolayers is their extremely high reproducible morphology accompanied by ultrahigh sensitivity which will be useful in many fields where a very small amount of analyte is available. Moreover the assembly can be reused a number of times after removing the already present molecules. The method of obtaining VA-GNRs is simple, inexpensive and reproducible. With the help of simulations of monolayers and multilayers it has been shown that superlattices can achieve better sensitivity than monolaver assembly of VA-GNRs.

关键词： nanostructures self-assemblies superlattices Raman spectroscopy sensors