Bhattacharyya B.,Indian Institute of Technology Roorkee
Archives of Computational Methods in Engineering | Year: 2017
Surrogate models are widely used to predict response function of any system and in quantifying uncertainty associated with the response function. It is required to have response quantities at some preselected sample points to construct a surrogate model which can be processed in two way. Either the surrogate model is constructed using one shot experimental design techniques, or, the sample points can be generated in a sequential manner so that optimum sample points for a specific problem can be obtained. This paper addresses a comprehensive comparisons between these two types of sampling techniques for the construction of more accurate surrogate models. Two most popular one shot sampling strategies: Latin hypercube sampling and Sobol sequence, and four different type sequential experimental designs (SED) namely, Monte Carlo intersite projected (MCIP), Monte Carlo intersite projected threshold (MCIPT), optimizer projected (OP) and LOLA-Voronoi (LV) method are taken for the present study. Two most widely used surrogate models, namely polynomial chaos expansion and Kriging are used to check the applicability of the experimental design techniques. Three different types of numerical problems are solved using the two above-mentioned surrogate models considering all the experimental design techniques independently. Further, all the results are compared with the standard Monte Carlo simulation (MCS). Overall study depicts that SED performs well in predicting the response functions more accurately with an acceptable number of sample points even for high-dimensional problems which maintains the balance between accuracy and efficiency. More specifically, MCIPT and LV method based Kriging outperforms other combinations. © 2017 CIMNE, Barcelona, Spain
Saleh T.A.,King Fahd University of Petroleum and Minerals |
Gupta V.K.,Indian Institute of Technology Roorkee
Advances in Colloid and Interface Science | Year: 2014
The remarkable increase in the number of vehicles worldwide; and the lack of both technical and economical mechanisms of disposal make waste tires to be a serious source of pollution. One potential recycling process is pyrolysis followed by chemical activation process to produce porous activated carbons. Many researchers have recently proved the capability of such carbons as adsorbents to remove various types of pollutants including organic and inorganic species. This review attempts to compile relevant knowledge about the production methods of carbon from waste rubber tires. The effects of various process parameters including temperature and heating rate, on the pyrolysis stage; activation temperature and time, activation agent and activating gas are reviewed. This review highlights the use of waste-tires derived carbon to remove various types of pollutants like heavy metals, dye, pesticides and others from aqueous media. © 2014 Elsevier B.V.
Devi K.,Indian Institute of Technology Roorkee
Expert Systems with Applications | Year: 2011
Decision making is the process of finding the best option among the feasible alternatives. In classical multiple-criteria decision making methods, the ratings and the weights of the criteria are known precisely. However, if decision makers are not able to involve uncertainty in the defining of linguistic variables based on fuzzy sets, the intuitionistic fuzzy set theory can do this job very well. In this paper, VIKOR method is extended in intuitionistic fuzzy environment, aiming at solving multiple-criteria decision making problems in which the weights of criteria and ratings of alternatives are taken as triangular intuitionistic fuzzy set. For application and verification, this study presents a robot selection problem for material handling task to verify our proposed method. © 2011 Elsevier Ltd. All rights reserved.
Chauhan A.,Indian Institute of Technology Roorkee |
Saini R.P.,Indian Institute of Technology Roorkee
Renewable and Sustainable Energy Reviews | Year: 2014
Uneconomical extension of the grid has led to generation of electric power at the end user facility and has been proved to be cost effective and to an extent efficient. With augmented significance on eco-friendly technologies the use of renewable energy sources such as micro-hydro, wind, solar, biomass and biogas is being explored. This paper presents an extensive review on various issues related to Integrated Renewable Energy System (IRES) based power generation. Issues related to integration configurations, storage options, sizing methodologies and system control for energy flow management are discussed in detail. For stand-alone applications integration of renewable energy sources, performed through DC coupled, AC coupled or hybrid DC-AC coupled configurations, are studied in detail. Based on the requirement of storage duration in isolated areas, storage technology options can be selected for integrated systems. Uncertainties involved in designing an effective IRES based power generation system for isolated areas is accounted due to highly dynamic nature of availability of sources and the demand at site. Different methodologies adopted and reported in literature for sizing of the system components are presented. Distributed control, centralized and hybrid control schemes for energy flow management in IRES have also been discussed. © 2014 Elsevier Ltd.
Upadhyay S.,Indian Institute of Technology Roorkee |
Sharma M.P.,Indian Institute of Technology Roorkee
Renewable and Sustainable Energy Reviews | Year: 2014
The demand of energy is increasing at an escalating pace and cannot be fulfilled entirely by conventional energy systems, due to their limited supplies. In addition to this they have a radical impact on the environment. In comparison to them hybrid energy systems are a suitable combination of renewable and non-renewable energy systems which keeps into account the advantages of both these systems, thus able to achieve reduction in cost of implementation and maintenance of the system, limited emission levels, improvement in reliability of the overall system etc. Designing of hybrid energy system for a locality and its implementation is an uphill task as the input parameters of the sources considered are randomly varying with time and are also independent of the load requirements. The paper encompasses review on various important sectors needed to be considered while designing and implementation of hybrid energy system; this includes configurations, criteria selection, sizing methodologies and control & energy management. This will help the designer to use suitable design constraints required while implementing hybrid energy system for grid connected or in off grid modes as per the requirement of the locality. © 2014 Elsevier Ltd.
Kumar A.,Indian Institute of Technology Roorkee |
Kumar V.,Indian Institute of Technology Roorkee
Chemical Reviews | Year: 2014
Colloidal MNPs of different sizes and shapes have been synthesized largely by the chemical reduction of metal salts in an aqueous or organic medium employing a number of reducing agents such as citric acid, sodium borohydride, hydrazine, ascorbic acid, poly(ethylene glycol), and formaldehyde/ sugars. Some other popular reducing agents which serve binary functions as both reducing and stabilizing agents used for the preparation of MNPs are poly(vinylpyrrolidone) (PVP) and ethylene glycol. Nucleic acids with long-range nanoscale order can control the nucleation and growth of nanocolloids effectively by binding of metals/metal ions or the metals of semiconductors to the specific sites of biomolecules. These materials will not only provide chemical functionality for integration but also make it possible to modify and manipulate the structure, morphology, and properties of the biomolecules conveniently through reorganization and self-assembly.
Maurya M.R.,Indian Institute of Technology Roorkee
Current Organic Chemistry | Year: 2012
Procedures for covalent bonding of ligands to polymer support and their reactions with molybdenum precursors to obtain polymer-supported molybdenum complexes are outlined. These supported molybdenum complexes are used as catalysts for organic transformations such as oxidation of alkenes, phenols, allyl alcohol, ethylbenzene and benzoin, and for polymerization reaction. Higher activity, recyclability and high turn over numbers of most supported catalysts are confirmed in many cases which offer real prospect for technological developments. © 2012 Bentham Science Publishers.
Chandra Srivastava V.,Indian Institute of Technology Roorkee
RSC Advances | Year: 2012
Sulfur compounds represent one of the most common impurities present in the crude oil. Sulfur in liquid fuel oil leads directly to the emission of SO 2 and sulfate particulate matter (SPM) that endangers public health and community property; and reduces the life of the engine due to corrosion. Furthermore, the sulfur compounds in the exhaust gases of diesel engines can significantly impair the emission control technology designed to meet NO x and SPM emission standards. The research efforts for developing conventional hydrodesulfurization and alternative desulfurization methods such as selective adsorption, biodesulfurization, oxidation/extraction (oxidative desulfurization), etc. for removing these refractory sulfur compounds from petroleum products are on the rise. Research laboratories and refineries are spending huge amounts of money in finding a viable and feasible solution to reduce sulfur to a concentration of less than 10 mg l -1. This paper reviews the current status in detail of various desulphurization techniques being studied worldwide. It presents an overview of novel emerging technologies for ultra-deep desulfurization so as to produce ultra-low-sulfur fuels. © 2012 The Royal Society of Chemistry.
Garg H.,Indian Institute of Technology Roorkee
ISA Transactions | Year: 2013
The main objective of the paper is to developed a methodology, named as vague Lambda-Tau, for reliability analysis of repairable systems. Petri net tool is applied to represent the asynchronous and concurrent processing of the system instead of fault tree analysis. To enhance the relevance of the reliability study, vague set theory is used for representing the failure rate and repair times instead of classical(crisp) or fuzzy set theory because vague sets are characterized by a truth membership function and false membership functions (non-membership functions) so that sum of both values is less than 1. The proposed methodology involves qualitative modeling using PN and quantitative analysis using Lambda-Tau method of solution with the basic events represented by intuitionistic fuzzy numbers of triangular membership functions. Sensitivity analysis has also been performed and the effects on system MTBF are addressed. The methodology improves the shortcomings of the existing probabilistic approaches and gives a better understanding of the system behavior through its graphical representation. The washing unit of a paper mill situated in a northern part of India, producing approximately 200 ton of paper per day, has been considered to demonstrate the proposed approach. The results may be helpful for the plant personnel for analyzing the systems' behavior and to improve their performance by adopting suitable maintenance strategies. © 2012 ISA.
Singh G.K.,Indian Institute of Technology Roorkee
Energy | Year: 2013
The various forms of solar energy - solar heat, solar photovoltaic, solar thermal electricity, and solar fuels offer a clean, climate-friendly, very abundant and in-exhaustive energy resource to mankind. Solar power is the conversion of sunlight into electricity, either directly using photovoltaic (PV), or indirectly using concentrated solar power (CSP). The research has been underway since very beginning for the development of an affordable, in-exhaustive and clean solar energy technology for longer term benefits. This paper, therefore, reviews the progress made in solar power generation research and development since its inception. Attempts are also made to highlight the current and future issues involved in the generation of quality and reliable solar power technology for future applications. A list of 121 research publications on the subject is also appended for a quick reference. © 2013 Elsevier Ltd.