National Institute of Technology, Silchar

About: National Institute of Technology, Silchar is a education organization based out in Silchar, Assam, India. It is known for research contribution in the topics: Computer science & Control theory. The organization has 1934 authors who have published 4219 publications receiving 41149 citations. The organization is also known as: NIT Silchar.

Mechanical Characterization of Bio-epoxy Green Composites Derived from Sodium Bicarbonate Treated Punica Granatum Short Fiber Agro-waste

Abstract: Investigations into green materials owing to the growing environmental concerns have become one of the hot topics for the scientific community. The present work aims to fabricate and investigate the mechanical and physical properties of short Punica granatum fiber (SPGF) reinforced bio epoxy (BE) biocomposites. The bio epoxy has been derived from cashew-nut shell oil. The composites are fabricated using different wt% of SPGF (10%, 20%, 30%, and 40%) that are chemically treated using 10 wt% sodium bicarbonate solution for different treatment duration i.e., 1 day, 5 days and 10 days. It has been revealed through the chemical characterization approach of X-ray diffraction (XRD) methodology that the aforementioned eco-friendly chemical treatment process doesn’t promote the transformation of the treated SPGFs to cellulose II from cellulose I. Thermogravimetric (TGA) analysis reveals degradation of hemicellulose as well as the pectin content of the SPGFs. The effect of the chemical treatment with varied treatment duration on the mechanical properties as such tensile, flexural, and impact properties of fabricated green composites are investigated. The physical properties such, water absorption, moisture content, and thickness swelling are also investigated. The mechanical properties of the fabricated composites weren’t affected by the alkaline treatment. However, better physical properties and mechanical properties were revealed for the composites fabricated using 5 days treated Punica granatum short fibers in comparison to other dissolution conditions. The alkaline treatment, therefore, proves to be effective in enhancing the properties of the composite specimen. The treatment process takes care of the environmental concerns as it is benign to the environment when disposed of in comparison to the strong alkaline treatment solutions. Moreover, the developed green composites promote sustainable and cleaner processing in the world of composites.

Nonlinear pyrocoupled deflection of viscoelastic sandwich shell with CNT reinforced magneto-electro-elastic facing subjected to electromagnetic loads in thermal environment

Abstract: The current work puts forward a finite element (FE)-based numerical formulation to evaluate the nonlinear deflections of multifunctional sandwich composite (MSC) shells. These shells possess a viscoelastic core, and face sheets made of functionally graded carbon nanotube-reinforced magneto-electro-elastic (FG-CNTMEE) materials. The viscoelastic core is considered to be temperature-dependent and is modelled via the complex modulus approach. Two different forms of viscoelastic cores, such as Dyad 606 and EC 2216, are considered in this study. The shell kinematics is realized with the aid of the higher-order shear deformation theory (HSDT). Furthermore, Donnell's nonlinear strain displacement relations are incorporated to account for the nonlinear behaviour. The total potential energy principle is utilized to get the global equations of motion which are solved using direct iterative method. Predominant emphasis is also placed to assess the impact of pyroeffects, coupling fields and electromagnetic (EM) boundary restrictions on the nonlinear deflections of MSC shells working in the thermal environment and subjected to EM loads, which is first of its kind. Also, parametric studies dealing with the shell geometries, CNT distributions and volume fractions, core-to-face sheet thickness ratio, aspect ratio, curvature ratio has been discussed in detail. The results of this work are believed to be unique and serve as a guide for the design engineers towards developing sophisticated smart structures for various engineering applications.

Optimal design of unit hydrographs using probability distribution and genetic algorithms

Abstract: A nonlinear optimization model is developed to transmute a unit hydrograph into a probability distribution function (PDF). The objective function is to minimize the sum of the square of the deviation between predicted and actual direct runoff hydrograph of a watershed. The predicted runoff hydrograph is estimated by using a PDF. In a unit hydrograph, the depth of rainfall excess must be unity and the ordinates must be positive. Incorporation of a PDF ensures that the depth of rainfall excess for the unit hydrograph is unity, and the ordinates are also positive. Unit hydrograph ordinates are in terms of intensity of rainfall excess on a discharge per unit catchment area basis, the unit area thus representing the unit rainfall excess. The proposed method does not have any constraint. The nonlinear optimization formulation is solved using binary-coded genetic algorithms. The number of variables to be estimated by optimization is the same as the number of probability distribution parameters; gamma and log-normal probability distributions are used. The existing nonlinear programming model for obtaining optimal unit hydrograph has also been solved using genetic algorithms, where the constrained nonlinear optimization problem is converted to an unconstrained problem using penalty parameter approach. The results obtained are compared with those obtained by the earlier LP model and are fairly similar.