Indian Institute of Technology Kharagpur

About: Indian Institute of Technology Kharagpur is a education organization based out in Kharagpur, India. It is known for research contribution in the topics: Computer science & Dielectric. The organization has 16887 authors who have published 38658 publications receiving 714526 citations.

Modelling and analyzing the watershed dynamics using Cellular Automata (CA)–Markov model – A geo-information based approach

Abstract: Improper practices of land use and land cover (LULC) including deforestation, expansion of agriculture and infrastructure development are deteriorating watershed conditions. Here, we have utilized remote sensing and GIS tools to study LULC dynamics using Cellular Automata (CA)–Markov model and predicted the future LULC scenario, in terms of magnitude and direction, based on past trend in a hydrological unit, Choudwar watershed, India. By analyzing the LULC pattern during 1972, 1990, 1999 and 2005 using satellite-derived maps, we observed that the biophysical and socio-economic drivers including residential/industrial development, road–rail and settlement proximity have influenced the spatial pattern of the watershed LULC, leading to an accretive linear growth of agricultural and settlement areas. The annual rate of increase from 1972 to 2004 in agriculture land, settlement was observed to be 181.96, 9.89 ha/year, respectively, while decrease in forest, wetland and marshy land were 91.22, 27.56 and 39.52 ha/year, respectively. Transition probability and transition area matrix derived using inputs of (i) residential/industrial development and (ii) proximity to transportation network as the major causes. The predicted LULC scenario for the year 2014, with reasonably good accuracy would provide useful inputs to the LULC planners for effective management of the watershed. The study is a maiden attempt that revealed agricultural expansion is the main driving force for loss of forest, wetland and marshy land in the Choudwar watershed and has the potential to continue in future. The forest in lower slopes has been converted to agricultural land and may soon take a call on forests occurring on higher slopes. Our study utilizes three time period changes to better account for the trend and the modelling exercise; thereby advocates for better agricultural practices with additional energy subsidy to arrest further forest loss and LULC alternations.

Preparation, characterization and properties of acid functionalized multi-walled carbon nanotube reinforced thermoplastic polyurethane nanocomposites

Abstract: The multi-walled carbon nanotube (MWNT) reinforced thermoplastic polyurethane (TPU) nanocomposites were prepared through melt compounding method followed by compression molding. The spectroscopic study indicated that a strong interfacial interaction was developed between carbon nanotube (CNT) and the TPU matrix in the nanocomposites. The microscopic observation showed that the CNTs were homogeneously dispersed throughout the TPU matrix well apart from a few clusters. The results from thermal analysis indicated that the glass transition temperature (Tg) and storage modulus (E′) of the nanocomposites were increased with increase in CNTs content and their thermal stability were also improved in comparison with pure TPU matrix. The rheological analysis showed the low frequency plateau of shear modulus and the shear thinning behavior of the nanocomposites. The electrical behaviors of the nanocomposites are increased with increase in weight percent (wt%) of CNT loading. The mechanical properties of nanocomposites were substantially improved by the incorporation of CNTs into the TPU matrix.

A Simple Direct Casting Route to Ceramic Foams

Abstract: A simple direct foaming and casting process using ovalbumin-based aqueous slurries for fabricating ceramic and metal foams is demonstrated. Foaming of aqueous ceramic slurries and the foam microstructure were seen to be a strong function of slurry rheology. Setting of foams with ceramic solids loading above 20 vol% was achieved by addition of acid, which also prevented binder migration. Acid addition resulted in excessive shrinkage, causing cracking of foams with ceramic loading below 20 vol%. Addition of sucrose to the slurries suppressed shrinkage leading to defect-free foams with porosity exceeding 95%. Overall porosity and foam microstructure could be controlled through ceramic solids loading, ovalbumin–water ratio, foaming time and sucrose amount, and sintering temperature. The ceramic foams fabricated by the process were strong enough to be green machined to different shapes.

Metal-free-photocatalytic reduction of 4-nitrophenol by resin-supported dye under the visible irradiation

Abstract: Reduction of 4-nitrophenol (4-NP) with NaBH 4 in the aqueous medium is a kinetically inert reaction, and generally the reaction occurs in the presence of metal/metal oxide nanoparticles. In the present study, the reduction of 4-nitrophenol (4-NP) has been carried out photocatalytically using the visible irradiation under a metal-free (eco-friendly) condition. By systematic screening, Eosin Y loaded resin is identified to be efficient in the reduction of 4-NP under the visible light. The effectiveness of the catalytic process depends upon the adsorption and the electron transfer. The adsorption favours the reaction molecules to come closer on the resin surface, and then reduction occurs by transfer of electrons. Gradual decrease in the absorbance at 400 nm confirms the decrease in concentration of the 4-NP. Simultaneously, there is an increase in absorbance at 300 nm infers the formation of 4-aminophenol (4-AP) during the photolysis. Results obtained from the irradiation on–off experiment suggests that the visible light irradiation is essential for the above processes, and also it indicates the sensitivity of the photocatalyst. The optimized reaction condition had been arrived from the results obtained after a series of experiments, including variation of catalytic dose, concentrations of 4-NP and the reducing agent (NaBH 4 ). The rate of the reaction is found to be pseudo first order kinetics, and the rate constant ( k ) value is 6.90 × 10 −2 min −1 , under the experimental condition. From the control experiments, it is identified that the photocatalyst is primarily serving as an electron carrier in the reaction mechanism.