Department of Chemistry
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Item A methodology for building neural networks models from empirical engineering data(Elsiever, 2000-12) Barai, Sudhir KumarNeural networks (NN) are general tools for modeling functional relationships in engineering. They are used to model the behavior of products and the properties of processes. Nevertheless, their use is often ad hoc. This paper provides a sound basis for using NN as tools for modeling functional relationships implicit in empirical engineering data. First, a clear definition of a modeling task is given, followed by reviewing the theoretical modeling capabilities of NN and NN model estimation. Subsequently, a procedure for using NN in engineering practice is described and illustrated with an example of modeling marine propeller behavior. Particular attention is devoted to better estimation of model quality, insight into the influence of measurement errors on model quality, and the use of advanced methods such as stacked generalization and ensemble modeling to further improve model quality. Using a new method of ensemble of SG(k-NN), one could improve the quality of models even if they are close to being optimal.Item Influence of specimen geometry on determination of double-K fracture parameters of concrete: a comparative study(Springer, 2008-07-03) Barai, Sudhir KumarComparative study on analytical method, simplified method and weight function approach for determination the double-K fracture parameters using three-point bend and compact tension tests specimen geometries is presented in the paper. The input data required for numerical calculations are obtained using Fictitious Crack Model. The study reports that the double-K fracture parameters computed depends on factors such as initial-notch length/depth ratios, specimen geometry and size-effect. In addition, it is demonstrated that the use of weight function will further improve the computational efficiency without loss of accuracy.Item Neural Network Models for Air Quality Prediction: A Comparative Study(Springer, 2007) Barai, Sudhir KumarThe present paper aims to find neural network based air quality predictors, which can work with limited number of data sets and are robust enough to handle data with noise and errors. A number of available variations of neural network models such as Recurrent Network Model (RNM), Change Point detection Model with RNM (CPDM), Sequential Network Construction Model (SNCM), and Self Organizing Feature Maps (SOFM) are implemented for predicting air quality. Developed models are applied to simulate and forecast based on the long-term (annual) and short-term (daily) data. The models, in general, could predict air quality patterns with modest accuracy. However, SOFM model performed extremely well in comparison to other models for predicting long-term (annual) data as well as short-term (daily) data.Item Recycled aggregate concrete: Particle Packing Method (PPM) of mix design approach(Elsiever, 2017-10) Barai, Sudhir KumarA sustainable and eco-friendly approach is essential for the construction industry, as it is one of the major sectors responsible for the depletion of the natural resources and the generation of greenhouse gases. In this context, the recycled aggregate (RA) is an effective alternative to natural aggregate. But, the use of RA has not gained popularity yet, because of the inferior quality of RA and yielded recycled aggregate concrete (RAC) using RA. The proposed Particle Packing Method (PPM) of design mix is executed along with the established Two Stage Mixing Approach (TSMA) to produce RAC by completely replacing the natural coarse aggregate. The synergistic effect of PPM design mix and TSMA on fresh and hardened stage performance of RAC were studied. In this context, a comparative analysis showed encouraging results for the PPM design mix as compared to the IS: 10262 (2009) method of mix design approach.Item Data mining applications in transportation engineering(Taylor & Francis, 2011-12-19) Barai, Sudhir KumarData mining is the extraction of implicit, previously unknown and potentially useful information from data. In recent time, data mining studies have been carried out in many engineering disciplines. In this paper the background of data mining and tools is introduced. Further applications of data mining to transportation engineering problems are reviewed. The application of data mining for typical example of ‘Vehicle Crash Study’ is demonstrated using commercially available data mining tool. The paper highlights the potential of data mining tool application in transportation engineering sector.Item Determining the double-K fracture parameters for three-point bending notched concrete beams using weight function(Wiley, 2010-06-16) Barai, Sudhir KumarParameters of universal form of weight functions having four terms and five terms are derived for edge cracks in finite width of plate. The standard Tada Green's function is taken as the basis for the derivation. The shape of universal form of weight functions considered enables closed form expressions for cohesive toughness of three-point bending test geometry of notched concrete beams due to linear cohesive stress distribution in the fictitious fracture zone. This solution provides a viable method to determine the double-K fracture parameters: the initiation toughness, inline image and the unstable toughness inline image for mode I fracture of concrete beam. A comparison with existing analytical method shows that the weight function method for determination of the double-K fracture parameters yields results without any appreciable error. The use of weight function will not only simplify the calculation to obtain the double-K fracture parameters, inline image and inline image but also it will avoid the need of skilled numerical integration technique due to singularity problem at the integral boundary.Item Determining double-K fracture parameters of concrete for compact tension and wedge splitting tests using weight function(Elsiever, 2009-05) Barai, Sudhir KumarThe paper presents use of universal form of weight functions for determining the double-K fracture parameters and on compact test and wedge splitting test specimens. The proposed method enables to obtain a closed form expression of cohesion toughness of concrete specimens. A comparison with existing analytical method shows that the weight function method for determination of double-K fracture parameters yields results without any appreciable error. Significant influence of initial notch to depth (a0/D) ratio on the double-K fracture parameters is not also observed. Finally, a possible definition of brittleness of concrete using double-K fracture parameters is proposed.Item Influence of incorporation of nano-silica and recycled aggregates on compressive strength and microstructure of concrete(Elsiever, 2014-11-30) Barai, Sudhir KumarThe present investigation deals with the study of compressive strength and characteristics of the Interfacial Transition Zone (ITZ) of concrete containing recycled aggregates and nano-silica. For this purpose, compressive strength at 7, 28, 90 and 365 days are determined for fully natural and recycled aggregate concrete mixes made with or without nano-silica. In addition to above, Vickers microhardness test and backscattered-mode scanning electron microscopic analysis is carried to characterize ITZ of concrete mixes. The results of study depict that full replacement of natural coarse aggregates with recycled ones have significant effect on compressive strength and ITZ characteristics of concrete. However, compressive strength and microstructure of concrete mixes improves with the incorporation of nano-silica.Item Concrete fracture models and applications(Springer, 2011) Barai, Sudhir KumarItem AN INVESTIGATION INTO THE USE OF ICT IN THE NIGERIAN CONSTRUCTION INDUSTRY (2005)(2005) Barai, Sudhir KumarThe 2002 global ICT rankings by the International Telecommunications Union (ITU) ranked Nigeria 27th among 51 African countries and 153rd among 178 countries in the world. It was against this background that the paper investigated the state of ICT in the Nigerian construction industry to highlight the level of ICT penetration, its impact in the industry and the constraints to its adoption. The study identified the factors significantly impacting the level of ICT use, grouping them into those internal to the industry and those external to it. A total of 136 respondents to a questionnaire survey, comprising, contractors, consultants and academic researchers, provided empirical data for the analysis. The results showed that some internal factors, i.e., the type of business (whether contracting, consulting or academic), chief executive officers (CEOs)/senior managers’ perception of the benefits of ICT and the years of computer literacy of the CEOs/senior managers were significantly correlated with the level of ICT use in the industry. However, none of the external factors were significantly correlated with the level of ICT use. The main uses of ICT in the industry are word processing, Internet communications, costing and work scheduling. The top five constraints to the use of ICT are insufficient/irregular power supply, high cost of ICT software and hardware, low job order for firms, fear of virus attacks and high rate of obsolescence of ICT software and hardware. A comparison with the results of similar studies in some industrialised and newly industrialised countries indicated that the proportion of firms using the computer is quite high for a developing like Nigeria. It also highlighted the large gap in access to electricity and other communications infrastructure between developed and developing countries