Birjhora Mahavidyalaya

Bongaigaon, India

Birjhora Mahavidyalaya

Bongaigaon, India
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Pathak B.,Dibrugarh University | Biswas J.,Birjhora Mahavidyalaya | Bharali C.,Dibrugarh University | Bhuyan P.K.,Dibrugarh University
Atmospheric Pollution Research | Year: 2015

Intensive fire ignition and cracker work activities takes place during the festival of light called Diwali in India, celebrated for a period of few days in the month of October or November every year. The firecracker releases several pollutants [such as particulate matter (PM), black carbon (BC), organics, trace gases] near the surface. The effect of firecrackers on the atmospheric constituents is evaluated over Dibrugarh by monitoring the concentrations of PM, PM10(particle radius ≤10 μm), PM2.5(particle radius ≤2.5 μm) and BC during the Diwali and post-Diwali days (5 days after the Diwali Festival) in the years 2009 and 2010. Monthly average concentrations of each species except for the Diwali and post Diwali days is considered as the background concentrations. The concentration levels of the pollutants as recorded on the Diwali days are found to be a number of times higher (5.33 and 2.50 times for PM10, 5.74 and 2.65 times for PM2.5, 1.21 and 1.66 times for BC for the year 2009 and 2010, respectively) than the background levels at the peak hours of the fire work activity. To delineate the contribution of fireworks to the high concentrations of the species we performed air mass back trajectory analysis using the NOAA-HYSPLIT model in order to examine the existence of the transported aerosols. The ten day accumulated MODIS fire maps are also analyzed to mark out the contribution of aerosols from biomass burning. These analyses reveal that the higher concentrations of near surface aerosols including BC during the festival is due to the local effect of firework activities, neither because of long-range transport nor due to biomass burning activities. However, the higher concentration of pollutants for short periods has not degraded air quality substantially to cause health risks to people exposed to the festival in this environment. © Author(s) 2015. This work is distributed under the Creative Commons Attribution 3.0 License.


Borah B.M.,Bongaigaon Refinery | Sarmah H.P.,Gauhati University | Roy R.,Birjhora Mahavidyalaya
Nature Environment and Pollution Technology | Year: 2011

Water samples from 20 different sources from Dhaligaon area were studied to access their potability fordrinking purpose. A total of 13 physico-chemical parameters have been investigated. In 50% of water samples pH was found below the permissible limit, while in 65% of water samples turbidity exceeded the permissible limit. The concentration of iron (Fe) was found within the permissible limit only in 20% of water samples. Other parameters like electrical conductivity, total suspended solids, calcium hardness, magnesium hardness, and total hardness were found within the permissible limit.


Sah O.P.,Birjhora Mahavidyalaya
Physics of Plasmas | Year: 2011

Localized nonlinear structures associated with dispersive Alfven waves are investigated in dusty plasma in the transition limit, i.e., α ≡ (β/2 Q) ∼ 1, where β is the ratio of thermal to magnetic pressure and Q is electron to ion mass ratio. Sagdeev pseudopotential is obtained from the basic governing equations, which is then numerically solved to study the existence and the behaviors of the nonlinear structures. It is found that both compressive and rarefactive solitons can coexist above and below certain critical α- values determined by the wave direction cosine (KZ) and the Mach number (M); and the compressive (rarefactive) solitons are much wider than the rarefactive ones for the case M < KZ (M>K Z). In addition, the rarefactive solitons are found to be converted into rarefactive double layers, for the case M >KZ, if the dust grains are negatively charged and their density exceeds certain critical value. © 2011 American Institute of Physics.


Sah O.P.,Birjhora Mahavidyalaya
Physics of Plasmas | Year: 2010

A detailed study of nonlinear excitations (solitons and double layers) of kinetic Alfvén waves in low but finite- ß electron-positron-ion plasma is presented using pseudopotential approach, which is valid for arbitrary wave amplitude. While sub- and super-Alfvénic solitonic structures and sub-Alfvénic double layer structures are found for both r (equilibrium positron-to-ion density ratio) <1 and r>1, super-Alfvénic double layers are found to be favorable in the region r>1. In any case, however, only compressive nonlinear excitations are found to exist. This contradicts the earlier result [H. Kakati and K. S. Goswami, Phys. Plasmas 7, 808 (2000)] predicting the existence of small-amplitude rarefactive sub- and super-Alfvénic kinetic Alfvén double layers under the assumption r1. The effects of positron/ion density, ion temperature, obliqueness of the wave propagation, and plasma- ß on nonlinear excitations are also examined. © 2010 American Institute of Physics.


Chakravarty P.,Birjhora Mahavidyalaya | Deka D.C.,Birjhora Mahavidyalaya | Sarma N.S.,Polymer Section | Sarma H.P.,Gauhati University
Desalination and Water Treatment | Year: 2012

The adsorptive behavior of heartwood powder of Areca catechu for copper(II) ion from synthetic wastewater has been investigated as a function of contact time, initial concentration of copper(II) ion, solution pH and biosorbent dosage, using batch method at room temperature. The optimum conditions for the metal adsorption were found to be at 0.5 g biosorbent dose, pH 5.5, and 30 min equilibrium time for the entire concentration range of the adsorbate. The equilibrium adsorption data were fitted to Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherm models and the model parameters were evaluated. The maximum adsorption capacity obtained from Langmuir isotherm model was found to be 9.578 mg g-1. The kinetic study showed that the pseudo-second-order kinetic model better described the biosorption process in comparison to pseudo-first-order, Elovich and intraparticle diffusion kinetic model. FT-IR spectrum analysis revealed that O-H, N-H and C-O groups present in the adsorbent were the primary copper(II) ion binding groups. © 2012 Desalination Publications. All rights reserved.


Baruah N.,Birjhora Mahavidyalaya | Sarma C.M.,Assam University
Indian Journal of Agricultural Research | Year: 2013

An experiment was conducted to study the effect of plant growth substances on reversal of reproductive character in Sechium edule L. Foliar spray of ethrel at 50, 100, 250, 500 and 1000 μg/ml was made to seedlings of S.edule. The spray of ethrel significantly increased female flowers over male which led to increase in fruit number. Number of female flowers gradually increased and ethrel at 250 μg/ml was the optimal concentration recording 39.7 number of female flowers as against 13.2 at control. On the contrary the number of male flower at 250 μg/ml was 30.7 as against 15.5 at control. CCC was also applied at 50, 100, 250, 500 and 1000 μg/ml to S.edule (L.) The femaleness was increased and 250 μg/ml of CCC emerged as optimum concentration recording 26.5 number of female flower against 14.9 at control. At the respective concentration the number of male flower was 13.1 against 16.3 at control. Thus excessive vegetative growth in S.edule L was reduced by both ethrel and CCC. The experiment established reversal of male flower to female leading to increase in number of fruits.


Chakravarty P.,Birjhora Mahavidyalaya | Sarma N.S.,Polymer Section | Sarma H.P.,Gauhati University
Chemical Engineering Journal | Year: 2010

The ability of abundantly available heartwood of Areca catechu to adsorb cadmium(II) ions from aqueous solution has been investigated through batch experiments at room temperature. Various sorption parameters such as contact time, initial concentration of cadmium(II) ion, solution pH and amount of the biomass on the adsorption capacity, were studied. The adsorbent was found to be effective for quantitative removal of cadmium(II) ions in acidic conditions and equilibrium has been achieved in 30. min at pH 6.0. The equilibrium adsorption data were fitted to Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherm models and the model parameters were evaluated. The kinetic study showed that the pseudo-second-order rate equation better described the biosorption process. The FT-IR spectrum analysis revealed that hydroxyl, carboxyl, amide and amine groups were major cadmium(II) binding groups. © 2010 Elsevier B.V.


Chakravarty P.,Birjhora Mahavidyalaya | Sarma N.S.,Polymer Section | Sarma H.P.,Gauhati University
Desalination | Year: 2010

Removal of lead(II) from aqueous solution was studied using the powder of heartwood of Areca catechu as a new biosorbent under batch method at room temperature. Various sorption parameters such as contact time, initial concentration of lead(II) ion, effect of pH and amount of the biomass on the adsorption capacity of the biosorbent were studied. The adsorbent was effective for the quantitative removal of lead(II) ions in acidic conditions and equilibrium has been achieved in 25. min. The equilibrium adsorption data were fitted to Langmuir and Freundlich adsorption isotherm models and the model parameters were evaluated. The kinetic study showed that the pseudo-second order rate equation better described the biosorption process. The FT-IR spectra of the adsorbent before and after treatment with lead(II) solution indicated that hydroxyl, carboxyl, amide and amine groups were major binding sites with the metal. This method is quite feasible, economic, time saving, and low cost. © 2010 Elsevier B.V.


Ahmed M.K.,Birjhora Mahavidyalaya | Sah O.P.,Birjhora Mahavidyalaya
Astrophysics and Space Science | Year: 2014

Taking into account of ion temperature effect, existence conditions of arbitrary amplitude solitary Kinetic Alfvén Waves (KAWs) in a plasma with q-nonextensive electrons are investigated by the conventional Sagdeev pseudo potential method. It is found that only solitons with density hump can exist, the amplitude of which depends sensitively on the parameter q, ion temperature (σ=Ti/Te) and plasma β. There is an upper limit of solitary wave amplitude which decreases with increase of q, σ and β. The amplitude of solitary KAWs is found to increase with increase in ion temperature. The results obtained in the framework of Maxwellian distribution are reproduced when q→1. © 2014 Springer Science+Business Media Dordrecht.

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