Showing papers by "Motilal Nehru National Institute of Technology Allahabad published in 2014"

Off-shore wind farm development: Present status and challenges

Abstract: Offshore wind farm (OWF) is an emerging technology in the wind energy conversion system. These wind resources are abundant, stronger, and are more consistent in terms of their availability than land-based wind resources. As a matter of fact significantly higher energy production is achieved due to larger wind turbine ratings and stronger wind profiles. This paper highlights the present scenario and challenges in development of offshore wind power. The challenges and opportunities that exist in the development stages of an offshore wind farm project, from exploration to erection and installation of wind turbines, construction of platforms and laying of sea cables, up to maintenance and de-commissioning, involving important technical aspects are addressed. An application of high voltage direct current (HVDC) transmission for integration of large scale offshore wind farm with onshore grid is attractive as compared to high voltage alternating current (HVAC) transmission system. To make the offshore wind farm feasible, reliable and secure, the different aspects in its planning, design and operation are also reviewed in this paper.

A Fuzzy AHP and PROMETHEE method-based heuristic for disassembly line balancing problems

Abstract: Nowadays, new products have been introduced in the market at an ever increasing pace due to rapid technology advancement. Consequently, products are becoming outdated and discarded faster than ever before. Since the demand for new solutions to economically deal with such outdated products begun to rise, the disassembly line has emerged as a viable solution to this problem. The disassembly line has been considered as a viable choice for automated disassembly of returned products. The problem of sequence generation in disassembly is complex due to its NP-Hard nature and therefore the heuristically solutions are most preferable for these types of problems. In this paper, a heuristic has been proposed to assign the disassembly tasks/parts to the work stations under its precedence constraints. It incorporates Fuzzy analytic hierarchy process (Fuzzy AHP) and PROMETHEE method for the selection of tasks for assignment to the disassembly line. The Fuzzy AHP has been used to find the relative importance of each cri...

Optimal Feature and Decision Tree-Based Classification of Power Quality Disturbances in Distributed Generation Systems

Abstract: Penetration of distributed generation systems in conventional power systems leads to power quality (PQ) disturbances. This paper provides an improved PQ disturbances classification, which is associated with load changes and environmental factors. Various forms of PQ disturbances, including sag, swell, notch, and harmonics, are taken into account. Several features are obtained through hyperbolic S-transform, out of which the optimal features are selected using a genetic algorithm. These optimal features are used for PQ disturbances classification by employing support vector machines (SVMs) and decision tree (DT) classifiers. The study is supported by three different case studies, considering the experimental setup prototypes for wind energy and photovoltaic systems, as well as the modified Nordic 32-bus test system. The robustness and precision of DT and SWM are performed with noise and harmonics in the disturbance signals, thus providing comprehensive results.

Organizational justice and employee engagement: Exploring the linkage in public sector banks in India

Abstract: Purpose – The purpose of this paper is to explore whether perceptions of distributive, procedural and interactional justice are related to employee engagement, as an extension of the antecedents-consequences model of Saks (2006), and to examine the possibility of inter-relationships between these three dimensions of justice Design/methodology/approach – A survey of 210 employees of public sector banks in India covered measures of job and organization engagement (OE) proposed by Saks (2006) and the scale on distributive, procedural and interactional justice developed by Niehoff and Moorman (1993) The relationships between justice perceptions and engagement were analysed using correlations and hierarchical regression analysis Findings – Results show that distributive, procedural and interactional are inter-related with each other Further, distributive and interactional justice take precedence over procedural justice in determining job engagement, while distributive justice plays the most important role

Influence of Cu doping on the structural, photoluminescence and formaldehyde sensing properties of SnO2 nanoparticles

Abstract: In this paper we report Cu doping induced modifications in the structural, photoluminescence and gas sensing behaviour of SnO2 nanoparticles. Our results show that crystallinity is reduced upon Cu doping. The PL emissions observed in the visible region are attributed to the defect levels arising due to oxygen vacancies. The 1.5 at% Cu-doped SnO2 shows the selective high response (∼80%) to 50 ppm concentration of formaldehyde over methanol, ethanol, propanol-2-ol, acetone and n-butylacetate at 200 °C. The sensing mechanism has been explained based on chemisorption of oxygen on the SnO2 surface and the subsequent reaction between the adsorbed oxygen species and the formaldehyde molecules.

Three-phase carbon fiber amine functionalized carbon nanotubes epoxy composite: processing, characterisation, and multiscale modeling

Abstract: The present paper discusses the key issues of carbon nanotube (CNT) dispersion and effect of functionalisation on the mechanical properties of multiscale carbon epoxy composites. In this study, CNTs were added in epoxy matrix and further reinforced with carbon fibres. Predetermined amounts of optimally amine functionalised CNTs were dispersed in epoxymatrix, and unidirectional carbon fiber laminateswere produced. The effect of the presence of CNTs (1.0 wt%) in the resin was reflected by pronounced increase in Young's modulus, inter-laminar shear strength, and flexural modulus by 51.46%, 39.62%, and 38.04%, respectively. However, 1.5wt% CNT loading in epoxy resin decreased the overall properties of the three-phase composites. A combination of Halpin-Tsai equations and micromechanics modeling approach was also used to evaluate the mechanical properties of multiscale composites and the differences between the predicted and experimental values are reported. These multiscale composites are likely to be used for potential missile and aerospace structural applications.

A survey on scheduling and load balancing techniques in cloud computing environment

Abstract: Now-a-days cloud computing is the most emerging technology due to its elasticity of resource provisioning and the pay-as-you-go pricing model which enables users to pay only according to their need. As cloud can be accessed anytime and anywhere through commodity hardware only its demand is increasing day by day. So it must provide high performance gain to the user and at the same time must be beneficial for the Cloud Service Provider (CSP). To achieve this goal many challenges have to be faced. Load balancing is one of them which helps the CSP to meet the QoS requirements of the users and at the same time maximize his profit by optimum use of the resources. To balance the load in cloud the resources and workloads must be scheduled in an efficient manner. A variety of scheduling algorithms are used by load balancers to determine which backend server to send a request to. The selected server allocates resources and schedules the job dynamically on some virtual machine (VM) located on the same physical machine. It is also the responsibility of the provider to dynamically reallocate or migrate the VM across physical machines for workload consolidation and to avoid over utilization or under utilization of resources. In this paper, we have discussed different algorithms proposed to resolve the issue of load balancing and task scheduling in Cloud Computing. We have mentioned some of their shortcomings for further development. VM migration issues involved in load balancing are also described briefly.

A Kano model, AHP and M-TOPSIS method-based technique for disassembly line balancing under fuzzy environment

Abstract: Recovery, recycling or remanufacturing of post-consumed products are viable alternatives for reducing the environmental problems resulting from the huge amounts of waste currently arriving at landfills. Disassembly operations are inevitable for product recovery therefore the disassembly line is an appropriate choice to carry out the same. A disassembly line balancing problem is how to streamline the disassembly activities, so that the total disassembly time required at each workstation is approximately the same. The assignment of jobs to workstations in a disassembly environment has been the matter of concern to researchers because the product, which has to be disassembled, have different types of materials. The main aim of a disassembly process is to reuse components and reduce undesirable impact on the environment. This paper applies a Kano model, fuzzy-AHP, and M-TOPSIS-based technique, shown to successfully find the optimal order of component removal using AND/OR precedence relation. The tasks are assigned to the disassembly workstations according to their priority rank and precedence relations. The proposed technique has been illustrated with an example and the results show improvements in the performance in comparison with other techniques.

Electrical discharge machining–based hybrid machining processes: A review

Abstract: Electrical discharge machining is one of the widely used noncontact-type advanced machining processes in which material removal takes place due to melting and vaporization by thermal energy of electric sparks. Electrical discharge machining has the capability of machining difficult-to-cut materials such as superalloys, advanced ceramics, and composites with complex shapes at both macro- and micro-levels. But its application is limited to electrically conductive materials. Other limitations include low material removal rate, high tool wear rate, recast layer formation, and geometrical inaccuracy in the form of taper and overcut. To overcome such limitations, the mechanism of electrical discharge machining has been combined with the mechanism of one or more other machining/physical/chemical processes. The mechanism of two constituent processes may be applied simultaneously or sequentially to constitute the hybrid machining process. It has been found that the performance of hybrid machining processes is bett...

Structural and alcohol response characteristics of Sn-doped WO3 nanosheets

Abstract: Sn-doped WO3 materials were synthesized by chemical co-precipitation route using sodium tungstate dihydrate (Na2WO4·2H2O) as the host precursor and stannic tetrachloride hydrated (SnCl4·5H2O) as the source of Sn dopant. X-ray diffraction (XRD) analyses confirm that the prepared materials are polycrystalline WO3, possessing monoclinic structure with crystallite sizes in the range 22–44 nm. The transmission electron microscopy (TEM) images of the samples show a sheet-like morphology embedded with small nanosized crystallites. The energy dispersive X-ray (EDX) analyses of the samples confirm incorporation of Sn ions into WO3 lattice network. The alcohol response characteristics of the samples were studied by measuring the change in its electrical resistance before and after exposure to test alcohol vapours at different operating temperatures (150–250 °C) for various concentrations (10–50 ppm) in air. On Sn doping, the response has been found to increase for all the test alcohols. It has been observed that at each operating temperature and concentration under investigation, the response to propan-2-ol is maximum, followed by those to ethanol and methanol. On Sn doping, the response and recovery times for all the test alcohols have been found to decrease relative to those observed in the case of undoped WO3 nanosheets.

Effect of sodium alginate modification of graphene (by ‘anion-π’ type of interaction) on the mechanical and thermal properties of polyvinyl alcohol (PVA) nanocomposites

Abstract: Layered aligned dispersion of graphene in graphene/polyvinyl alcohol (PVA) nanocomposites is prepared in the form of films through simple solution processing route. The results indicate that there exist an interfacial interaction between PVA and graphene because of hydrogen bonding. This is responsible for the change in structure of PVA (such as decrease in the level of crystallization) and exhibiting ductile PVA nanocomposite film with improved tensile modulus, tensile strength, and thermal stability. Moreover, to improve the mechanical properties of PVA nanocomposites, graphene is successfully modified using a non-covalent modifier, sodium alginate (SA) and there exist an ‘anion-π’ type of interaction in between SA and graphene. The modification results in finer dispersion of the graphene in PVA/SA-m-graphene nanocomposites. In addition, there exist a hydrogen bonding in between PVA and SA. This has resulted in the remarkable improvement in mechanical properties of PVA/SA-m-graphene nanocomposites as co...

In situ grafted nanostructured ZnO/carboxymethyl cellulose nanocomposites for efficient delivery of curcumin to cancer

Abstract: In this present manuscript, zinc oxide (ZnO) nanoparticles embedded carboxymethyl cellulose (CMC) bionanocomposite were prepared by in situ grafting and the hydrophobic anticancer drug curcumin (Cur) was loaded into it. Structural, morphological, and physiochemical behavior of prepared curcumin-loaded CMC/ZnO nanocomposites (NCs) were characterized by FTIR, XRD, SEM, TEM, TGA, and DTA. The drug entrapment efficiency was evaluated and the in vitro efficacy as anticancer drug delivery vehicle was analyzed. The potential toxicity of curcumin-loaded ZnO/CMC NCs (Cur/ZnO/CMC NCs) was studied by using L929 and MA104 cell lines via MTT assay. The cellular uptake study of Cur/ZnO/CMC NCs by normal (L929) and cancer (MA104) cells carried out by using ethanol extraction and by FACS analysis has been reported. The results of this investigation demonstrate that the nanomatrix synthesized can effectively deliver the anticancer drug curcumin, and hence appears to be a promising nanoformulation for anticancer therapy and other biomedical applications.

On the polymeric foams: modeling and properties

Abstract: Polymeric foams are now widely used and researched. The physical properties of polymeric foam can be related to a set of independent structural parameters or variables of the foam. Study of these variables and correlation with commercial FE packages is essential for reliable and faster product development. Some aspects of foam behavior are widely studied while some are little less, like correlation of physical unloading behavior. For example, a lot of work in the area of phenomenological constitutive modeling of uniaxial loading was done, though research in areas of unloading–reloading and their correlation still demands more attention. Increasing number of OEMs and suppliers are moving to computer simulations in the design phase to assess their future products. Hence, different parameters within FE packages play a significant role and also affect the results. Appropriate use of these parameters will narrow down error band and automatically reduce the cycle time and development cost. This brief review is expected to set the perspective for major research work done so far in terms of FE modeling correlation and constitutive modeling of polymeric foam vis-a-vis to its properties.

Experimental Study of Traveling Wire Electrochemical Spark Machining of Borosilicate Glass

Abstract: Machining performance study of newly developed machining processes has always been a challenge to make them industrially viable. Traveling wire electrochemical spark machining (TW-ECSM) is a newly developed hybrid process in the area of nontraditional machining process which can be effectively utilized for difficult-to-cut electrically nonconductive very hard and brittle materials. Present paper discusses the investigations showing the effect of input process variables on material removal rate (MRR) and kerf width (K w) during the cutting of borosilicate glass using self-developed tabletop TW-ECSM setup. The experimental studies are conducted under varying applied voltage, pulse-on time, pulse-off time, electrolyte concentration, and wire feed velocity. The experimental results shows that MRR and K w increase with increase in applied voltage as well as pulse-on time, but these performance characteristics decrease with increase in pulse-off time. MRR and K w increase with increase in electrolyte concentrat...

On similarity solutions of Zabolotskaya–Khokhlov equation

Abstract: The new closed form solutions of the ( 2 + 1 )-dimensional Zabolotskaya–Khokhlov equation are constructed by using the similarity transformations method via Lie group theory. The Zabolotskaya–Khokhlov equation has been reduced into a new partial differential equation with smaller number of independent variables. Further using the similarity transformations method the new partial differential equation is reduced into an ordinary differential equation. The ordinary differential equation provides semi analytical solutions. Elastic behaviour of multisolitons and dromion annihilation of solutions are analyzed physically through their evolutional profiles.