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Jagiroad, India

Adhikari G.,Jagiroad College | Bhattacharyya K.G.,Gauhati University
Environmental monitoring and assessment | Year: 2015

This work investigates the correlations existing among soil organic carbon (C), nitrogen (N), phosphorous (P), potassium (K), and physicochemical properties like clay mineralogy, textural components, soil aggregation, and land use pattern. Seven different locations were chosen in the tropical rainforest climate region of Assam, India, for the work. The soil texture classifications were clay, sandy clay loam, and sandy loam with mixed clay mineralogy consisting of tectosilicates and phylosilicates. Two distinct compositions of total Fe/Al oxides≥11.5 and <10.8% were observed along with two distinct groups of water stable soil aggregates of mean weight diameter≈6.42 and ≤3.26 mm. The soil clay and sand had positive and negative contributions respectively to the soil organic carbon (SOC) protection, which was observed to be dependent on lesser sand content, higher silt+clay content, and the presence of higher percentages of total Fe/Al oxides. Soil clay mineralogy suggested that the mineral, chlorite, favored retention of higher SOC content in a particular site. Under similar climatic and mineralogical conditions, both natural and anthropogenic soil disturbances destabilized SOC protection through SOM mineralization and soil aggregate destabilization as indicated by SOC protective capacity studies. Urbanization resulting in soil compaction contributed to enhanced SOC level through increased contact between the occluded organic carbon and the soil mineralogical constituents.

Deka R.Kt.,Gauhati University | Neog B.Ch.,Jagiroad College
ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) | Year: 2012

An exact solution to the one-dimensional unsteady natural convection flow past an impulsively started infinite vertical plate with combined effect of thermal stratification and radiation under the influence of transverse magnetic field is presented. The solutions for fluid velocity, temperature are obtained by the Laplace transformation technique. Comparison is made between the solutions with and without thermal stratification and the differences in both the cases are presented graphically. Comparison reveals that thermal stratification has significant impact on convection flow past vertical plates on radiating MHD flows. Copyright © 2012 by ASME.

Banerjee P.,Jagiroad College | Bezboruah T.,Gauhati University
Lecture Notes in Engineering and Computer Science | Year: 2014

This paper theoretically examines the key dipole antenna parameters that define their performances in terms of current distribution, radiation resistance, input impedance, radiation efficiency, size, bandwidth, quality factor and directivity. We have investigated how these parameters are related to each other and also how variation of one alters the overall performance of the antenna.

Adhikari G.,Jagiroad College | Bhattacharyya K.G.,Gauhati University
Ecotoxicology | Year: 2015

In this work, several physicochemical properties of sub-tropical soil (up to 20 cm depth) like water holding capacity, organic carbon content, cation exchange capacity, texture, pH, and electrical conductivity were determined along with the trace metals, Co, Cr, Cu, Mn, Ni, Pb and Zn, in order to evaluate inter-relations among the trace metals and the soil properties. The contribution of the trace metals to ecotoxicological risk was assessed using various tools. Cr, Cu, Mn and Zn contents were found to be lower than the world average, but Co, Ni, and Pb had higher contents. The trace metal concentrations were utilized to obtain the pollution index and the potential ecotoxicological aspects. The trace metals were shown to have come from similar origin and their retention in the soil was contributed by properties like organic carbon, cation exchange capacity, clay content and water holding capacity of the soil. The pollution index showed that the trace metals had the sequence of Pb (considerably polluted) > Co, Ni (moderately polluted) > Cr, Cu, Mn and Zn (unpolluted). The composite ecological risk index was the highest in agricultural land with irrigation and fertilizer use, and was the lowest in the forest land. © 2015 Springer Science+Business Media New York

Adhikari G.,Jagiroad College | Bhattacharyya K.G.,Gauhati University
Environmental Monitoring and Assessment | Year: 2015

The present study was carried out to evaluate the impact of the effluents and the solid wastes generated by a giant pulp and paper mill in the northeastern part of India on soil mineralogy of the area. The impacts were monitored by analysis of soil samples from seven sites located in the potential impact zone and a control site where any kind of effluent discharge or solid waste dumping was absent. The soil belonged to medium texture type (sandy clay loam, sandy loam, loamy sand, and silt loam), and the soil aggregate analysis indicated higher levels of organic carbon, pH, electrical conductivity, effective cation exchange capacity, and mean weight diameter at sites receiving effluents and solid wastes from the pulp and paper mill. Depletion in soil silica level and in feldspar and quartz contents and rise in iron and calcium contents at the sites receiving effluents from the pulp and paper mill indicated significant influence on soil mineralogy. The soil contained a mixture of minerals consisting of tectosilicates (with silicate frameworks as in quartz or feldspar), phylosilicates (layered clays like kaolinite, smectite, chlorite, illite, etc.), and carbonates. Absence of pure clay minerals indicated a state of heterogeneous intermediate soil clay transformation. The significance of the mixed mineralogy in relation to the disposal of effluents and dumping of solid wastes is discussed in details. © 2015, Springer International Publishing Switzerland.

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