Showing papers by "Motilal Nehru National Institute of Technology Allahabad published in 2012"
TL;DR: In this paper, the effects of nanofluid (Al2O3 in water 2, 3 and 4 vol%) and water as coolants on heat transfer, frictional losses, and exergy loss in a counter flow corrugated plate heat exchanger were experimentally investigated.
225 citations
TL;DR: Comparison study between wavelet transform (WT) and S-transform (ST) based on extracted features for detection of islanding and power quality (PQ) disturbances in hybrid distributed generation (DG) system demonstrates the advantages of S -transform over WT in detection of Islanding and different disturbances under noise-free as well as noisy scenarios.
Abstract: In this paper, comparative study between wavelet transform (WT) and S-transform (ST) based on extracted features for detection of islanding and power quality (PQ) disturbances in hybrid distributed generation (DG) system is presented. The hybrid system consists of DG resources like photovoltaic, fuel cell, and wind energy systems connected to grid. The negative sequence component of the voltage signal is used in islanding detection of these resources from the grid. Voltage signal extracted directly at the point of common coupling is considered for detection of PQ disturbances. Further, the effect of variation of grid impedances on islanding and PQ disturbances and effect of islanding on the coherency between the energy resources is also presented in this paper. The study for different scenarios of DG system is presented in the form of time-frequency analysis. The energy content and standard deviation of ST contour and WT signal is also reported in order to validate the graphical results. The results demonstrate the advantages of S -transform over WT in detection of islanding and different disturbances under noise-free as well as noisy scenarios.
219 citations
TL;DR: A tremendous effort has been made over the past decade to develop and test films with antimicrobial properties to improve food safety and shelf-life and this review highlights the preparation, mechanism, antimicrobial activity, optimization of biocide properties of chitosan films and applications including biocatalysts for the improvement of quality and shelf life of foods.
Abstract: In recent years, active biomolecules such as chitosan and its derivatives are undergoing a significant and very fast development in food application area. Due to recent outbreaks of contaminations associated with food products, there have been growing concerns regarding the negative environmental impact of packaging materials of antimicrobial biofilms, which have been studied. Chitosan has a great potential for a wide range of applications due to its biodegradability, biocompatibility, antimicrobial activity, nontoxicity and versatile chemical and physical properties. It can be formed into fibers, films, gels, sponges, beads or nanoparticles. Chitosan films have been used as a packaging material for the quality preservation of a variety of foods. Chitosan has high antimicrobial activities against a wide variety of pathogenic and spoilage microorganisms, including fungi, and Gram-positive and Gram-negative bacteria. A tremendous effort has been made over the past decade to develop and test films with antimicrobial properties to improve food safety and shelf-life. This review highlights the preparation, mechanism, antimicrobial activity, optimization of biocide properties of chitosan films and applications including biocatalysts for the improvement of quality and shelf-life of foods.
166 citations
TL;DR: A numerical technique based on polynomial differential quadrature method (PDQM) to find the numerical solutions of two-dimensional sine-Gordon equation with Neumann boundary conditions and it is shown that the technique is easy to apply for multidimensional problems.
137 citations
TL;DR: In this article, the effect of alkali treatment on the composition and structure of Napier grass fibers was studied by chemical, FTIR and solid-state 13 C NMR methods.
132 citations
TL;DR: It was found that the reduction in workability and compressive strength, due to partially replacement of sand by waste plastic, is minimal and can be enhanced by addition of superplasticizer.
Abstract: The fresh and hardened properties of waste virgin plastic mix concrete have been studied (CUR Report 1991). A number of concrete mixes were prepared in which sand was partially replaced by waste plastic flakes in varying percentages by volume. Waste plastic mix concrete with and without superplasticizer was tested at room temperature. Forty-eight cube samples were moulded for compressive strength tests at three, seven, and twenty-eight days. Eight beams were also cast to study the flexural strength characteristic of waste plastic mix concrete. It was found that the reduction in workability and compressive strength, due to partially replacement of sand by waste plastic, is minimal and can be enhanced by addition of superplasticizer.
132 citations
TL;DR: In this article, the authors presented a model and optimization of cut quality during pulsed Nd:YAG laser cutting of thin Al-alloy sheet for straight profile, where the hybrid approach comprising of Taguchi methodology (TM) and response surface methodology (RSM) is used for modelling whereas multiobjective optimization is performed using hybrid approach of TM and grey relational analysis (GRA) coupled with entropy measurement methodology.
Abstract: Thin sheets of aluminium alloys are widely used in aerospace and automotive industries for specific applications. Nd:YAG laser beam cutting is one of the most promising sheetmetal cutting process for cutting sheets for any profile. Al-alloy sheets are difficult to cut by laser beam because of its highly reflective nature. This paper presents modelling and optimization of cut quality during pulsed Nd:YAG laser cutting of thin Al-alloy sheet for straight profile. In the present study, four input process parameters such as oxygen pressure, pulse width, pulse frequency, and cutting speed and two output parameters such as average kerf taper (Ta) and average surface roughness (Ra) are considered. The hybrid approach comprising of Taguchi methodology (TM) and response surface methodology (RSM) is used for modelling whereas multi-objective optimization is performed using hybrid approach of TM and grey relational analysis (GRA) coupled with entropy measurement methodology. The entropy measurement methodology is employed for the calculation of weight corresponding to each quality characteristic. The results indicate that the hybrid approaches applied for modelling and optimization of the LBC process are reasonable.
110 citations
TL;DR: In this article, a residential building of usable floor area about 85.5 m2 located at Hyderabad (Andhra Pradesh), India is evaluated under different envelopes and climates in Indian context.
105 citations
TL;DR: In this article, a genetic algorithm based multi-objective optimization for the laser cutting of a Titanium alloy sheet (grade 5) was proposed to simultaneously optimize the kerf taper and surface roughness.
Abstract: Titanium and its alloys have high demand in different industries due to their superior properties The conventional cutting methods face difficulties for cutting these alloys due to their poor thermal conductivity, low elastic modulus and high chemical affinity at elevated temperatures Laser cutting may be used for quality cuts by proper control of different process parameters The aim of present research is to simultaneously optimize kerf taper and surface roughness in the laser cutting of Titanium alloy sheet (grade 5) The developed regression models for kerf taper and surface roughness have been taken as objective functions for the genetic algorithm based multi-objective optimization The paper presents optimal solutions and improvements in different quality characteristics thereof The significant control factors have been found with further discussion of their effect on two important quality characteristics kerf taper and surface roughness
105 citations
TL;DR: A numerical technique based on polynomial differential quadrature method (PDQM) to find the numerical solutions of two dimensional hyperbolic telegraph equation with Dirichlet and Neumann boundary condition is proposed.
104 citations
TL;DR: In this paper, a hybrid approach, obtained by combining robust parameter design methodology and fuzzy logic theory has been applied to compute the fuzzy multi-response performance index, which is further used for multi-objective optimization.
TL;DR: It is observed that the value of saturation magnetization in case of Fe3O4/alg NCs decreases by increasing the pH value, which is a function of pH at which the synthesis has been done.
TL;DR: In this paper, the diameters of the SnO 2 nanoparticles fall into a small range of 1-5nm, with the majority being less than the exciton Bohr radius of SnO2 (∼2.7nm).
TL;DR: The application of an elasto-plastic model based explicit finite element analysis (FEA) to model the erosion behaviour in abrasive water jet machining (AWJM) yields largely improved results.
TL;DR: In this article, the authors present a model of the multi-stage global supply chain network problem incorporating a set of risk factors (such as: late shipment, exchange rates, quality problems, logistics and transportation breakdown, and production risks), their expected values and probability of their occurrence, and associated additional cost.
Abstract: Facility location decisions play a vital role in the strategic design of the global supply chain. Global supply chains are vulnerable towards different types of risks factor that causes disturbance in the allocation of certain goods at the required place and time, and with the required quality and quantity. This paper presents a model of the multi-stage global supply chain network problem incorporating a set of risk factors (such as: late shipment, exchange rates, quality problems, logistics and transportation breakdown, and production risks), their expected values and probability of their occurrence, and associated additional cost. Different scenarios are considered to demonstrate the applicability of the model. Optimal decisions regarding the facility locations and inter-echelon quantity flows in the global supply chain are based on initial information for the risk factors. Further, if any change in the expected value of risk factor has occurred, the inter-echelons shifting take place to minimize the overall cost of the supply chain.
TL;DR: In this paper, the authors presented a life cycle energy analysis of different types of residential buildings (one storey, two storey and duplex and multi storey) in Indian context.
TL;DR: The aim of present work was to bioremediate the waste cooking oil using a novel lipase produced in solid medium containing waste grease and wheat bran by Penicillium chrysogenum, and showed that the enzyme could be employed for the bioremediation of used cooking oil.
TL;DR: In this article, the authors presented for the first time correlations for greenhouse gas (GHG) emissions from small hydropower schemes in India, which can be used to predict life cycle GHG emissions based on capacity, head and type of SHP schemes.
TL;DR: This paper proposes a new pairing-free CLAKA protocol that has better performance and is provably secure in a very strong security model-the extended Canetti-Krawczyk (eCK) model.
Abstract: Since certificateless public key cryptography (CLPKC) has received widespread attention due to its efficiency in avoiding key escrow problems in identity-based public key cryptography (ID-PKC), the certificateless authenticated key agreement (CLAKA) protocol, an important part of CLPKC, has been studied a great deal. Most CLAKA protocols are built from pairings which need costly operations. To improve the performance, several pairing-free CLAKA protocols have been proposed. In this paper, we propose a new pairing-free CLAKA protocol. Compared with the related protocols, our protocol has better performance. Also, our protocol is provably secure in a very strong security model-the extended Canetti-Krawczyk (eCK) model.
TL;DR: In this article, the authors aim to ascertain the predictors of training effectiveness with special reference to the characteristics of trainers, including comfort level with the subject matter and trainer's rapport with trainees.
Abstract: Purpose – The paper aims to ascertain the predictors of training effectiveness with special reference to the characteristics of trainers.Design/methodology/approach – Characteristics of trainers as obtained from the extant literature served as seven independent variables to predict training effectiveness, measured in terms of trainee satisfaction with the training programme. Data were collected by administering a structured questionnaire on employees selected through simple random sampling. A total of 80 responses were obtained and subjected to multiple regression analysis.Findings – Of the seven independent variables, only two, namely trainer's comfort level with the subject matter and trainer's rapport with trainees, were found to be the significant predictors of trainee satisfaction. Hence, the hypothesis that all seven independent variables are significant predictors of trainee satisfaction was partially proved.Originality/value – Training programmes should be designed keeping in mind the knowledge le...
TL;DR: In this paper, a polycrystalline In 2 O 3, possessing cubic structure with lattice parameters, was grown on cleaned glass substrates by the chemical spray pyrolysis technique using the precursor solution of indium nitrate (In (NO 3 ) 3 ).
TL;DR: In this article, an intelligent approach for the modelling of die sinking electrochemical spark machining (DS-ECSM) process using finite element method (FEM) and artificial neural network (ANN) in integrated manner.
Abstract: Die sinking–electrochemical spark machining (DS–ECSM) is one of the hybrid machining processes, combining the features of electrochemical machining (ECM) and electro-discharge machining (EDM), used for machining of nonconducting materials. This article reports an intelligent approach for the modelling of DS–ECSM process using finite element method (FEM) and artificial neural network (ANN) in integrated manner. It primarily comprises development of two models. The first one is the development of a thermal finite element model to estimate the temperature distribution within the heat-affected zone (HAZ) of single spark on the workpiece during DS–ECSM. The estimated temperature field is further post-processed for determination of material removal rate (MRR) and average surface roughness (ASR). The second one is a back propagation neural network (BPNN)-based process model used in a simulation study to find optimal machining parameters. The BPNN model has been trained and tested using the data generated from th...
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TL;DR: In this paper, the authors identify the critical KSBs and their mutual influences and categorize them into two categories: driving and dependent KSBS. The authors used Interpretive Structural Modeling (ISM) methodology to evolve mutual relationship among the KSB Ss.
Abstract: Knowledge Sharing (KS) is the foundation stone to Knowledge Management (KM). Some variables hinder KS in the organizations. These variables are known as Knowledge Sharing Barriers (KSBs). The objective of this paper is to identify the critical KSBs and their mutual influences. Identification of KSBs which are at the root of hierarchy (called driving KSBs) and those which are at the top of the hierarchy (called dependent KSBs) is the main aim of this research work. The Interpretive Structural Modeling (ISM) methodology has been used to evolve mutual relationship among the KSBs. It is observed that two KSBs, namely, ‘lack of top management commitment’ and ‘KM is not well understood’, have high driving power and therefore deserve serious attention. Arrangement of KSBs in a hierarchy and their categorization into driver and dependent categories is an exclusive effort in the area of KM. The study concludes with a discussion and the managerial implications.
TL;DR: In this article, a generalized frequency domain method is proposed to obtain the switching frequency formulation for hysteresis current controlled voltage source inverter (VSI)-based shunt compensator.
Abstract: In this paper, a generalized frequency domain method is proposed to obtain the switching frequency formulation for hysteresis current controlled voltage source inverter (VSI)-based shunt compensator. The formulation obtained from the high-frequency model based on the Tsypkin's method explicitly shows the relation between the maximum switching frequency with the system and design parameters. The shunt compensator has been used for the load compensation in a distribution system for both weak and strong feeder supplying a nonlinear load. The maximum switching frequency has been shown related with hysteresis bandwidth and parameters of the VSI, feeder, and load of the distribution system. It is shown that the feeder and load reactance has a significant effect in determining the maximum switching frequency for the weak feeder distribution systems. However, the maximum switching frequency is mainly dependent upon the shunt compensator parameters for strong feeder distribution systems. The minimum switching frequency in general depends upon the modulation depth of the VSI. The results are verified using as power systems CAD (PSCAD) simulation studies for single-phase load compensation. A laboratory model distribution system has been used for the experimental verification.
TL;DR: Low-power Majority-function-based 1-bit full addersthat use MOS capacitors (MOSCAP) in its structure is presented that helps in reducing power consumption, propagation delay, and area of digital circuits while maintaining low complexity of logic design.
Abstract: This paper presents a comparative study of high-speed and low-voltage full adder circuits. Our approach is based on hybrid design full adder circuits combined in a single unit. A high performance adder cell using an XOR-XNOR (3T) design style is discussed. This paper also discusses a high-speed conventional full adder design combined with MOSCAP Majority function circuit in one unit to implement a hybrid full adder circuit. Moreover, it presents low-power Majority-function-based 1-bit full addersthat use MOS capacitors (MOSCAP) in its structure. This technique helps in reducing power consumption, propagation delay, and area of digital circuits while maintaining low complexity of logic design. Simulation results illustrate the superiority of the designed adder circuits over the conventional CMOS, TG, and hybrid adder circuits in terms of power, delay, power delay product (PDP), and energy delay product (EDP). Postlayout simulation results illustrate the superiority of the newly designed majority adder circuits against the reported conventional adder circuits. The design is implemented on UMC0.18 µm process models in Cadence Virtuoso Schematic Composer at 1.8 V single-ended supply voltage, and simulations are carried out on Spectre S.
30 Apr 2012
TL;DR: Several simulations conducted using different voltage supplies, load capacitors and temperature variation demonstrate the superiority of the XOR (3T) based full adder designs in term of delay, power and power delay product (PDP) compared to the other fullAdder circuits.
Abstract: This paper presents comparative study of high-speed, low-power and low voltage full adder circuits. Our approach is based on XOR-XNOR design full adder circuits in a single unit. A low power and high performance 9T full adder cell using a design style called “XOR (3T)” is discussed. The designed circuit commands a high degree of regularity and symmetric higher density than the conventional CMOS design style as well as it lowers power consumption by using XOR (3T) logic circuits. Gate Diffusion Input (GDI) technique of low-power digital combinatorial circuit design is also described. This technique helps in reducing the power consumption and the area of digital circuits while maintaining low complexity of logic design. This paper analyses, evaluates and compares the performance of various adder circuits. Several simulations conducted using different voltage supplies, load capacitors and temperature variation demonstrate the superiority of the XOR (3T) based full adder designs in term of delay, power and power delay product (PDP) compared to the other full adder circuits. Simulation results illustrate the superiority of the designed adder circuits against the conventional CMOS, TG and Hybrid full adder circuits in terms of power, delay and power delay product (PDP).
TL;DR: A Fuzzy c-Means (FCM) clustering approach is proposed to determine the optimal number of clusters in WSN and the optimal numbers determined by FCM has been compared with those obtained by analytical method.
Abstract: Wireless sensor networks (WSNs) are resource constrained systems that needs efficient utilisation of all available resources. Clustering is well-known technique to achieve high scalability and efficient resource allocation in WSNs. This paper presents an approach to determine optimal number and location of cluster head. The Fuzzy c-Means (FCM) clustering algorithm that uses X-axis and Y-axis coordinates of spatially distributed sensor nodes to form clusters is used in study. A random deployment of 100 nodes in 100 × 100 m² area is considered here. The optimal number of cluster heads (CHs) so determined is also compared with those obtained by analytical method. The life time analysis in terms of first node dead is also presented in optimally clustered network.
TL;DR: In this article, a co-precipitation method with SnCl4·5H2O as the starting material and Zn(CH3COO)2·2H2Os as the source of dopant was used to obtain polycrystalline SnO2 possessing tetragonal rutile structure with crystallite sizes in the range 11-25nm.
TL;DR: In this article, the effect of coupling agents and alkali treatment of fibers on tensile, flexural and impact properties of composites was studied and the mechanical properties and interfacial bonding were found to improve when surface modified fibers were employed in the composites.
Abstract: Natural fine fibers were extracted from Borassus fruits belonging to the Arecaceae family. To improve the surface, these fibers were treated with aq NaOH solution. Composites were prepared by the hand lay up process using both the untreated and alkali-treated Borassus fine fibers as reinforcement and unsaturated polyester resin as matrix. The effect of a coupling agent and alkali treatment of fibers on tensile, flexural and impact properties of the composites was studied. The mechanical properties and interfacial bonding were found to improve when surface modified fibers were employed in the composites. This is due to the improvement of chemical bonding between the treated fibres and polyester matrix as also supported by Fourier transform infrared results. Water absorption by the different composite types was also found to be negligible.
TL;DR: The Zn-doped SnO 2 nanoparticles synthesized by the chemical co-precipitation route and having dopant concentration varying from 0 to 4 at%, were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) for structural and morphological studies.