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Basumatary S.,Bineswar Brahma Engineering College | Deka D.C.,Gauhati University
International Journal of ChemTech Research

Transesterification of yellow oleander (Thevetia peruviana) seed oil to its fatty acid methyl esters (FAME, biodiesel) was carried out in methanol by batch reaction using a heterogeneous catalyst derived from the rhizome of Musa balbisiana Colla (one variety of banana plant). The yield of biodiesel obtained is 95 wt.% at room temperature (32 °C) in 3 h. The catalyst is thermally stable and better catalytic activity is observed when it is activated. Source

Bora P.,Bineswar Brahma Engineering College | Bora P.,Tezpur University | Konwar L.J.,Tezpur University | Deka D.,Tezpur University
Energy Conversion and Management

The present investigation aims to highlighten the effect of monoglyceride surfactant (GMO) on structure and dynamic behavior and other fuel characteristics of microemulsion based hybrid biofuels (MHBFs). Fuel quality of MHBFs formulated using purified GMO (>90%), which was prepared by esterification of glycerol, was investigated in the study. Phase behaviors, droplet size distribution, number of droplets present in the system, average droplet size and average length of surface active agents were studied as a part of structural investigations of the GMO based MHBFs. Diffusion coefficient, energy barrier to droplet coalescence and rate of coalescence of droplets were also investigated for the formulated MHBFs. The number of droplets, length of surface active agent and the diffusion co-efficient were in the ranges of 1.87 × 1021-5.66 × 1021/m3, 0.92-1.07 nm and 1.00 × 10-11-1.79 × 10-11 m2/s, respectively. The rate of droplet coalescence was obtained in the range 2.77 × 10-4-8.78 × 10-4 times the collision factor. MHBFs incorporating the glycerol derived bio-based nonionic surfactant GMO exhibited viscosity of 4.12 mm2/s (at 40 °C), gross calorific value (GCV) of 39.17 MJ/kg and pour point of -7 °C. © 2016 Elsevier Ltd. All rights reserved. Source

Baudron P.,Ecole Polytechnique de Montreal | Baudron P.,IRD Montpellier | Baudron P.,General Electric | Sprenger C.,Kompetenzzentrum Wasser Berlin | And 3 more authors.
Environmental Earth Sciences

This study aimed at characterizing the groundwater flow pattern in a semi-arid agricultural area in northern India crossed by an intermittent monsoon-controlled watercourse, the Najafgarh drain. More specifically, it focused on studying the impact of groundwater recharge from the riverbed to the regional aquifer using hydrogeochemical and isotopic data. Significant hydrogeochemical zonation was observed between the northern, central and southern sides of the drain, linked to different mineralization processes and mixings. Northward from the drain, groundwater was mainly brackish (4.1–23.4 mS/cm), due to dissolution of evaporites (halite and anhydrite). Southward from the drain, mostly fresh groundwater was found (from 0.5 to 2.3 mS/cm), revealing notable cation exchange processes. In the vicinity of the drain (central area), mineralization was intermediate (0.7–4 mS/cm) and groundwater showed low geochemical evolution, supposing a distinct origin. Stable isotopes of water (δ18O, δ2H) confirmed that central groundwater was not a simple mixing between northern and southern groundwater masses, but had a significant component of infiltrated surface water from the drain. Potentiometric data supported these findings and confirmed the contribution of the drain to the recharge of the aquifer, setting up a hydraulic barrier between north and south, despite surface water availability limited to the monsoon season and low hydraulic conductivity of the riverbed. This study demonstrates the value of the geochemical and isotopic analysis of groundwater to characterize groundwater flow pattern in peri-urban agricultural areas, especially surface water–groundwater interactions. © 2016, Springer-Verlag Berlin Heidelberg. Source

Sarmah P.,Gauhati University | Sarmah P.,Bineswar Brahma Engineering College | Das B.K.,Gauhati University
Indian Journal of Chemistry - Section A Inorganic, Physical, Theoretical and Analytical Chemistry

The supported catalyst produced by immobilising the cobalt(III)-oxo cluster Co4O4(O2CMe)4(py)4 on chemically modified mesoporous silica shows very good activity in the tert-butyl hydroperoxide oxidation of styrene and diphenylmethane. While complete conversion of styrene takes place to yield styrene epoxide at moderate selectivity, diphenylmethane is completely converted to obtain benzophenone at excellent selectivity. Source

Borah P.,Tezpur University | Borah P.,Bineswar Brahma Engineering College | Singh M.K.,University of Liege | Mahapatra S.,Tezpur University
Sustainable Cities and Society

Efficient use of energy in buildings has become a necessity due to increasing heating and cooling energydemand. Degree-days are a versatile climatic indicator that can be used to estimate the heating andcooling energy requirement for a building. In this study, heating degree-days (HDD) and cooling degree-days (CDD) are estimated for warm and humid, cool and humid and cold and cloudy climatic zonesof North-East India. The daily maximum and minimum temperature data are collected from RegionalMeteorological Centre, Guwahati. The degree-days are calculated by using three different methods, i.e.ASHRAE formula, UKMO equations and Schoenau-Kehrig method for different base temperatures. It hasbeen found that there is a variation in degree-days obtained from the above methods in the respectiveclimatic zone and also varies from zone to zone. The degree-days are also estimated on hourly basis basedon Typical Meteorological Year (TMY) data for validation. Generalized equations are developed by usingmultiple linear regression technique to estimate the degree-days and those satisfied the statistical testsare proposed. The developed equations can be used to obtain degree-days of locations in same climaticzone for which daily temperature data are not available, with a fair accuracy. © 2014 Elsevier Ltd. Source

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