National Institute of Technology Calicut

About: National Institute of Technology Calicut is a education organization based out in Kozhikode, Kerala, India. It is known for research contribution in the topics: Computer science & Control theory. The organization has 3627 authors who have published 4638 publications receiving 50830 citations. The organization is also known as: Calicut Regional Engineering College & NIT Calicut.

Photocatalytic degradation of metformin and amoxicillin in synthetic hospital wastewater: effect of classical parameters

Abstract: In this study, photocatalytic degradation of synthetic hospital wastewater containing two pharmaceutical contaminants, namely amoxicillin trihydrate (a commonly used antibiotic) and metformin HCl (a widely used diabetic medicine), was carried out using a laboratory-scale photoreactor (200 mL), TiO2 as photocatalyst, and 125 W low-pressure mercury vapour lamp emitting UV rays at 365 nm. The response surface methodology based on face-centred central composite design was used to optimize the independent variables, namely the initial concentrations of contaminants (10–50 mg/L), TiO2 dosage (250–1250 mg/L), initial pH (3–11), and reaction time (30–150 min). Results showed that both amoxicillin and metformin removals were influenced by all the four variables individually and also by the interaction between these variables. Response surface and overlaid contour plots were used to evaluate the optimum conditions. It was found that the maximum removal of amoxicillin (90%) and metformin (98%) could occur when the pH is 7.6, TiO2 dosage is 563 mg/L, and reaction time is 150 min for an initial concentration of the contaminants at 10 mg/L. Further experiments were conducted to evaluate the characteristics of photocatalytic degradation. Low adsorption of contaminants on TiO2 surface and negligible degradation of contaminants using acetonitrile as solvent suggest that hydroxyl radical attack could be the predominant pathway in the removal process. The COD and TOC analyses of the samples confirmed the mineralization of the compounds to more than 60%.

Enhancing the K-means Clustering Algorithm by Using a O(n logn) Heuristic Method for Finding Better Initial Centroids

Abstract: With the advent of modern techniques for scientific data collection, large quantities of data are getting accumulated at various databases. Systematic data analysis methods are necessary to extract useful information from rapidly growing data banks. Cluster analysis is one of the major data mining methods and the k-means clustering algorithm is widely used for many practical applications. But the original k-means algorithm is computationally expensive and the quality of the resulting clusters substantially relies on the choice of initial centroids. Several methods have been proposed in the literature for improving the performance of the k-means algorithm. This paper proposes an improvement on the classic k-means algorithm to produce more accurate clusters. The proposed algorithm comprises of a O(n logn) heuristic method, based on sorting and partitioning the input data, for finding the initial centroids in accordance with the data distribution. Experimental results show that the proposed algorithm produces better clusters in less computation time.

Liquid-liquid Slug Flow in a Microchannel Reactor and its Mass Transfer Properties - A Review

Abstract: Mass transfer is a basic phenomenon behind many processes like reaction, absorption, extraction etc. Mass transfer plays a significant role in microfluidic systems where the chemical / biological process systems are shrinkened down to a micro scale. Micro reactor system, with its high compatibility and performance, gains a wide interest among the researchers in the recent years. Micro structured reac-tors holds advantages over the conventional types in chemical processes. The significance of micro re-actor not limited to its scalability but to energy efficiency, on-site / on-demand production, reliability, safety, highly controlled outputs, etc. Liquid-liquid two phase reaction in a microreactor system is highly demandable when both reactants are liquids or when air medium cannot be suitable. This arti-cle overviews various liquid-liquid flow regimes in a microchannel. Discussions on the hydrodynamics of flow in micro scale are made. Considering the importance of mass transfer in liquid-liquid systems and the advantage of slug regime over other regimes, the article focuses especially on the mass trans-fer between two liquid phases in slug flow and the details of experimental studies carried out in this area. The advantages of slug flow over other flow regimes in micro structured reactor applications are showcased. © 2014 BCREC UNDIP. All rights reserved Received: 31st May 2014; Revised: 6th August 2014; Accepted: 14th August 2014 How to Cite : Antony, R., Giri Nandagopal, M.S., Sreekumar, N., Rangabhashiyam, S., Selvaraju, N. (2014). Liquid-liquid Slug Flow in a Microchannel Reactor and its Mass Transfer Properties - A Review. Bulletin of Chemical Reaction Engineering & Catalysis ,9(3): 207-223. (doi:10.9767/bcrec.9.3.6977.207-223) Permalink/DOI : http://dx.doi.org/10.9767/bcrec.9.3.6977.207-223

Natural fiber hybrid composites—A comparison between compression molding and resin transfer molding

Abstract: Short randomly oriented intimately mixed banana and sisal hybrid fiber-reinforced polyester composites having varying volume fraction of fiber were fabricated by compression molding (CM) and resin transfer molding (RTM) techniques by keeping the volume ratio of banana and sisal, 1:1. The static mechanical properties such as tensile, flexural, and impact behavior were studied. The dynamic mechanical properties were also evaluated. Resin transfer molded composites showed enhanced static and dynamic mechanical properties, compared with the compression molded samples. To analyze the fracture surface morphology of the composites, scanning electron microscopy (SEM) was also performed. Water sorption studies revealed that the water uptake of RTM fabricated composites was lower than that of the compression molded composites. The void content of the RTM composites was also found to be lower than that of the other one. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers