检索结果-南通市图书馆

Open Journal of Ecology 2011年第3期1卷 65-72页

作者： Subhajit Das tarun kumar Sarkar Minati de Dipnarayan Ganguly Tusher Kanti Maiti Abhishek Mukherjee Tapan kumar Jana tarun kumar de 不详

Populations of culturable microbes and activities of dehydrogenase & ?-D glucosidase were found maximum in surface soil and decreased with increase in depth in Sundarban mangrove *** maximum (13.529 X 106 C.F.U g-1 dry weight of soil) and minimum (11.547 X 106 C.F.U g-1 dry weight of soil) total microbial popu- lations in surface soil were recorded during po- st-monsoon and monsoon respectively. At 60 cm depth, the lower (6.396 X 106 C.F.U g-1 dry weight of soil) and higher (8.003 X 106 C.F.U g-1 dry weight of soil) numbers of total microbial populations were observed during monsoon and post-monsoon respectively. A decreasing trend of total microbial load, enzyme activities and nutrient status with organic carbon were found with increase in depth throughout the year. Present study revealed the relationship among depth integrated variations of physico-chemical compo- nents (viz. soil temperature, pH, moisture, orga- nic-C, .nitrogen, and available-P) and microbial populations as well as activity of dehydrogenase and ?-D glucosidase enzymes.

关键词： Sundarban Mangrove Sediment Enzyme Activities depth Microbial Populations

Optimization of Cultural Condition and Synergistic Effect of Lactose with Carboxymethyl Cellulose on Cellulase Production by <i>Bacillus</i>sp. Isolated from Fecal Matter of Elephant (<i>Elephas maximus</i>)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Microbiology 2013年第3期3卷 280-288页

作者： Sangrila Sadhu Pallab kumar Ghosh tarun kumar de Tushar Kanti Maiti Microbiology Laboratory Department of Botany the University of Burdwan Burdwan India

A cellulase producing bacterium (E3 strain) was isolated from fecal matter of elephant and identified as Bacillus sp. using 16S rDNA sequenced based molecular phylogenetic approach. While studying the effect of substrates like Carboxymethyl cellulose (CMC), avicel, starch, maltose, sucrose, glucose, fructose, galactose and lactose on cellulase production, it was found that CMC was best carbon source induced cellulase production followed by lactose in this bacterial strain. A positive synergistic effect of lactose with CMC was also observed with enhancement of 5 - 6 times in cellulase production. The optimum cellulase production was recorded with 1% CMC and 1% lactose when added individually in the Omeliansky’s medium. The results showed that addition lactose with CMC greatly enhances the production and activity of various cellulase enzymes. The optimal fermentation conditions for the biosynthesis of cellulase by this strain were found to be temperature: 37℃, pH 7.0. The nitrogen source NH4Cl at 0.15% was optimum for cellulase production by this bacterium.

关键词： Avicelase β-Glucosidase Carboxymethyl Cellulase (CMCase) Lactose

Salt tolerant culturable microbes accessible in the soil of the Sundarban Mangrove forest, India

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Ecology 2011年第2期1卷 35-40页

作者： Subhajit Das Minati de Raghab Ray Dipnarayan Ganguly Tapan kumar Jana tarun kumar de department of Marine Science Calcutta University 35 B.C. Road Calcutta-700 019

Sundarban Mangrove forest is highly productive marine ecosystem where halophilic microbes actively participate in bio-mineralization and biotransformation of minerals. The population of aerobic halophilic microbes was studied to determine their distribution with the availability of different physicochemical parameters with increasing depth of this forest sediment. The present study revealed that microbes present in the top soil region were less tolerant to fluctuation in salinity than the middle and bottom segment. Microbes isolated from bottom segment showed higher growth rate in anaerobic condition. A decreasing trend of total microbial population and organic carbon content of soil were found with increase in depth. In contrary a reverse profile was found for salinity. A significant stratification was found to exist among microbial population and the salty nature of the soil of Sundarban Mangrove forest.

关键词： Sundarban Mangrove Forest Ecosystem Halophilic Microbes Aerobic Condition Anaerobic Condition

Soil Urease Activity of Sundarban Mangrove Ecosystem, India

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Microbiology 2017年第8期7卷 617-632页

作者： Subhajit Das Dipnarayan Ganguly Abhishek Mukherjee Sabyasachi Chakraborty tarun kumar de department of Marine Science University of Calcutta Kolkata India

Vertical occurrence of soil urease activity along with ammonia content from three distinct regions viz. deep forest region (No tidal action and wave attack occurs as it is furthest from river shore and it contains maximum content of organic carbon and minimum soil salinity and silicate concentration. In this zone plenty of pneumatophores, below ground root and dense vegetation are found), Rooted region (It is situated in between deep forest region and Un-rooted region. This region contains only pneumatophores but it is devoid of long roots and vegetations. It faces wave attack and tidal action less than that of Un-rooted region) and Un-rooted region (It is closest to river shore and faces maximum wave attack and tidal action;it contains minimum organic carbon but maximum soil salinity and silicate concentration. This zone is totally devoid of any roots, pneumatophores and vegetations) of Sundarban mangrove forest ecosystem, India revealed an interesting explanation. Soil urease activity showed a decreasing pattern with increase in depth from the deep forest region of the Sundarban forest ecosystem. Soil urease activity was found to be more sensitive to soil temperature and pH rather than soil salinity. This ensured that soil urease along with the microbes present in the Sundarban forest ecosystem are more tolerant to fluctuation in salinity than that of temperature. Soil ammonia concentration was found to be directly governed by the soil urease activity [The regression equation is Ammonia in soil = -1.64 + 0.0402 Urease Activity (R-Sq = 62.9%, P < 0.001, n = 41)].

关键词： Soil Urease Activity Soil Ammonia deep Forest Region Rooted Region Un-Rooted Region and Sundarban Forest Ecosystem

determining the relationship between chemical composition and size, shape and effective density of airborne fine particles through concurrent use of inertial and optical based measurements

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2016年第5期14卷 93-101页

作者： Anand kumar tarun Gupta Environmental Engineering and Management Program Indian Institute of Technology Kanpur Kanpur 208016 India Institute of Atmospheric and Climate Science Swiss Federal Institute of Technology Zurich Zurich 8092 Switzerland department of Civil Engineering Indian Institute of Technology Kanpur Kanpur 208016 India

This study presents the development of a medium flow, multiple slit based PM2.5 （particle aerodynamic diameter 〈2.5 μm） inertial impactor. Its performance was compared with that of a light scattering based optical particle sizer in a field study and in controlled lab based experiments using polydisperse dolomite powder as test aerosol. The impactor＇s optimum nozzle configuration had a cutoff size of 2.51 μm （aero- dynamic diameter） at an operating flow rate of 215 L/rain with a pressure drop of 0.35 kPa across the impactor stage. Because the apparent particle density of an ambient aerosol depends on the physical properties and the chemical composition of the particles, the PM2.5 mass concentration was measured with an optical particle sizer and an inertial impactor over a weekday and a weekend day in a field study during which the effective particle shape factor and density were in tandem modified in order to com- pare the results from the two sampling techniques. The correlation of the two instrument results tended towards 1：1 with increasing values of shape factor （irregular shaped） and effective particle density. This observation was supported through chemical investigations of the collected mass, which showed a higher percentage contribution from elements which are mostly of crustal nature （namely, Ca, Fe, and Mg）.

关键词： lmpactor PM2.5 Optical particle counter Effective particle density Shape factor

Effect of relaxation times on circular crested waves in thermoelastic diffusive plate

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) 2010年第4期31卷 493-500页

作者： Rajneesh kumar tarun KANSAL department of Mathematics Kurukshetra University

The propagation of circularly crested thermoelastic diffusive waves in an infinite homogeneous transversely isotropic plate subjected to stress free, isothermal/insulated and chemical potential conditions is investigated in the framework of different thermo- elastic diffusion theories. The dispersion equations of thermoelastic diffusive Lamb type waves are derived. Some special cases of the dispersion equations are also deduced.

关键词： wave propagation transversely generalized thermoelastic diffusion attenuation isotropic crested waves phase velocity coefficient amplitudes

Propagation of Rayleigh waves on free surface of transversely isotropic generalized thermoelastic diffusion

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2008年第11期29卷 1451-1462页

作者： Rajneesh kumar tarun Kansal department of Mathematics Kurukshetra UniversityKurukshetra-136 119India

The present paper is devoted to the study of Rayleigh wave propagation in a homogeneous, transversely isotropic, thermoelastic diffusive half-space, subject to stress free, thermally insulated/isothermal, and chemical potential boundary conditions in the context of the generalized thermoelastic diffusion theory. The Green-Lindsay（GL） theory is used in the study. In this theory, thermodiffusion and thermodiffusion mechanical relaxations are governed by four different time constants. Secular equations for surface wave propagation in the considered media are derived. Anisotropy and diffusion effects on the phase velocity, attenuation coefficient are graphically presented in order to present the analytical results and make comparison. Some special cases of frequency equations are derived from the present investigation.

关键词： wave propagation transversely isotropic generalized thermoelastic diffusion phase velocity attenuation coefficient

Effects of rotation and tidal distortions on the shapes of radial velocity curves of polytropic models of pulsating variable stars

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2018年第6期18卷 17-26页

作者： tarun kumar Arvind kumar Lal Ankush Pathania School of Mathematics Thapar University

Anharmonic oscillations of rotating stars have been studied by various authors in literature to explain the observed features of certain variable stars. However, there is no study available in literature that has discussed the combined effect of rotation and tidal distortions on the anharmonic oscillations of stars. In this paper, we have created a model to determine the effect of rotation and tidal distortions on the anharmonic radial oscillations associated with various polytropic models of pulsating variable stars. For this study we have used the theory of Rosseland to obtain the anharmonic pulsation equation for rotationally and tidally distorted polytropic models of pulsating variable stars. The main objective of this study is to investigate the effect of rotation and tidal distortions on the shapes of the radial velocity curves for rotationally and tidally distorted polytropic models of pulsating variable stars. The results of the present study show that the rotational effects cause more deviations in the shapes of radial velocity curves of pulsating variable stars as compared to tidal effects.

关键词： stars: rotation stars: oscillations stars: binaries technique: radial velocities

Effect of interaction of the various modes on the radial velocity curves of the polytropic models of rotationally and tidally distorted pulsating variable stars

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2018年第12期18卷 53-66页

作者： tarun kumar Ankush Pathania Arvind kumar Lal School of Mathematics Thapar Institute of Engineering and Technology

In our previous work, we developed a model to study the effects of rotation and/or tidal distortions on anharmonic radial oscillations and hence on the radial velocity curves of the polytropic models of pulsating variable *** considered the first three modes(fundamental and the next two higher modes) for the polytropic models of index 1.5 and 3.0 in that *** the present paper, we are further extending our previous work to study the effect of the interaction of various modes on anharmonic radial oscillations and hence on radial velocity curves of the rotationally and/or tidally distorted polytropic models of pulsating variable *** this purpose, we have considered the following cases:(i) fundamental mode(ii) fundamental and the first mode,(iii) fundamental and the next two modes and finally(iv) fundamental and the next three higher modes of pulsation in our *** objective of this paper is also to investigate whether the interaction of various modes affects the results of our previous study or *** results of this study show that the interaction of the fundamental mode with higher modes appreciably changes the shape of the radial velocity curve of rotationally distorted and rotationally and tidally distorted polytropic models of pulsating variable stars.

关键词： stars:rotation stars:oscillations stars:binaries technique:radial velocities

Viscosity and Diffusion Effects at the Boundary Surface of Viscous Fluid and Thermoelastic Diffusive Solid Medium

在线全文

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2011年第2期3卷 219-238页

作者： Rajneesh kumar tarun Kansal department of Mathematics Kurukshetra UniversityKurukshetra-136119India

This paper concentrates on the wave motion at the interface of viscous compressible fluid half-space and homogeneous isotropic,generalized thermoelastic diffusive *** wave solutions in both the fluid and thermoelastic diffusive half-spaces have been investigated;and the complex dispersion equation of leaky Rayleigh wave motion have been *** phase velocity and attenuation coefficient of leaky Rayleigh waves have been computed from the complex dispersion equation by using the Muller’s *** amplitudes of displacements,temperature change and concentration have been *** effects of viscosity and diffusion on phase velocity and attenuation coefficient of leaky Rayleigh waves motion for different theories of thermoelastic diffusion have been depicted graphi*** magnitude of heat and mass diffusion flux vectors for different theories of thermoelastic diffusion have also been computed and represented graphically.

关键词： Viscous compressible fluid isotropic thermoelastic diffusion phase velocity attenuation coefficient.