Faculty Publications
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Item Shortcomings of Vibrating Screen and Corrective Measures: A Review(Springer Nature, 2020) Shanmugam, B.K.; Vardhan, H.; Govinda Raj, M.; Kaza, M.; Sah, R.; Harish, H.Screening is a process of separating two or more materials of size ranging from fine to coarse of different shapes, particle sizes and densities. The conventional vibrating screen is widely used in mineral and mining industries for performing sizing operation. This paper will be on the review of the various shortcomings of the conventional vibrating screen. The review was carried out through literature survey and plant visit. The paper also involves the remedial measures to be taken to overcome the shortcomings of the conventional vibrating screen. Some of the corrective measures are reduction in number of components also reduces overall screen load, angular velocities, stress, wear or damages to the screen, screen replacement, downtime and overall cost of production. The circular vibrating motion provided to the screen will give larger amplitude and stroke length of the screen which increases screening efficiency. The overall outcome of remedial action will lead to improved screening efficiency. This paper also provides the idea for the optimization of the vibrating screen design which can reduce the power consumption, friction and also provide high screening output. © 2020, Springer Nature Switzerland AG.Item Comparison of Wear Behaviour of Al–12.5Si Alloy Reinforced with ZrO2 Using Spray Deposition and Stir Casting Technique(Springer Science and Business Media Deutschland GmbH, 2023) Patil, I.S.; Rao, S.S.; Herbert, M.A.Aluminium silicon alloy materials are commonly used in aerospace and automotive engineering applications due to their enhanced stiffness, excellent wear resistance and lightweight. The measurement of wear properties for these combinations is very tangled. This can differ under different operating conditions. Dry sliding wear properties of Al–12.5Si with reinforced zirconium oxide matrix composite have been investigated using stir casting and spray deposition methods. The weight fraction of ZrO2 is 15%. The influence of applied nominal load (10 to 60 N) was investigated using the design of experiments. Wear properties of the hybrid composites were studied using pin-on-disc machine. The study found that the wear behaviour was improved by increasing the composition the zirconium oxide in alloy silicon matrix in both stir casting and spray forming techniques. The spray forming method showed lesser wear rate compared with stir casting method. Microstructure of the developed hybrid composites was analysed using scanning electron microscope (SEM). The developed hybrid composite samples have twice the improvement in wear resistance using spray deposition. The influence of reinforced zirconium oxide in aluminium silicon metal matrix on the wear properties using spray forming method is highlighted. This study shows that the wear resistance of the metal matrix composites can be improved by increasing the ZrO2 composition in aluminium silicon matrix. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Friction factor of CP aluminium and aluminium-zinc alloys(2006) Vidhya Sagar, N.; Anand, K.S.; Mithun, A.C.; Srinivasan, K.Friction factor has been determined for CP aluminium and aluminium-zinc alloys using ring compression test at different temperatures from 303 K to 773 K. It is found that CP aluminium exhibits sticking whereas Al-Zn alloys do not exhibit sticking at elevated temperatures. Hot working of Al-Zn alloy is easier than that of CP aluminium at 773 K. As zinc content increases up to 10 wt% the friction factor decreases up to 0.02. © Indian Academy of Sciences.Item Influence of die angle on containerless extrusion of commercially pure titanium tubes(2007) Srinivasan, K.; Venugopal, P.Containerless tube extrusion has been investigated with commerically pure titanium at room temperature and a strain rate of 0.07 s-1 using 20 conical dies of five different strains and four different angles with MoS2 lubricant. Theoretical punch pressures have been calculated using appropriate equations from slab analysis of the process and compared with experimentally determined punch pressures. It is found that there exists an optimum angle at which the punch pressure is the least at a given strain.Item Formability limit in containerless (open die) extrusion of commercial purity titanium rods and tubes(2008) Srinivasan, K.; Venugopal, P.Containerless extrusion requires far less forces compared to conventional direct extrusion of rods and tubes due to the elimination of container wall-billet friction. But the strains that can be imparted are less in the former due to the unsupported billet which gets upset first if the axial stress exceeds yield stress of the billet material. If this stress is equal to yield stress, it corresponds to the limit of the process of pure containerless extrusion. It is found that this limit strain as predicted by theory is far less compared to what is observed experimentally. This discrepancy is explained on the basis of heating that takes place in the deformation zone due to ideal, frictional, and shear work done in carrying out the extrusion process.Item Steam as coolant and lubricant in turning of metal matrix composites(2008) Shetty, R.; Pai B, R.B.; Kamath, V.; Rao, S.S.Green cutting has become focus of attention in ecological and environmental protection. Steam is cheap, pollution-free and eco-friendly, and then is a good and economical coolant and lubricant. Steam generator and steam feeding system were developed to generate and feed steam. Comparative experiments were carried out in cutting AA6061-15 vol.% SiC (25 ?m particle size), with cubic boron nitride (CBN) insert KB-90 grade under the conditions of compressed air, oil water emulsion, steam as coolant and lubricant, and dry cutting, respectively. The experimental results show that, with steam as coolant and lubricant, gradual reduction in the cutting force, friction coefficient, surface roughness and cutting temperature values were observed. Further, there was reduction in built up edge formation. It is proved that use of water steam as coolant and lubricant is environmentally friendly. © 2008 Zhejiang University and Springer-Verlag GmbH.Item Effect of substrate surface roughness on wetting behaviour of vegetable oils(2009) Prabhu, K.N.; Fernades, P.; Kumar, G.Vegetable oils are mainly used in the heat treating industry due to their environmental friendliness. In the present work the effect of surface roughness on spreading of vegetable oils on stainless steel substrates was investigated. Spreading phenomenon was digitally recorded and analyzed. All of the oils under investigation exhibited power law spreading behaviour of the type: A = ktn, where A, t, k and n represent the drop base contact area, spreading time, constant and exponent, respectively. The coconut and sunflower oils exhibited accelerated kinetics owing to their lower viscosity as compared to palm and mineral oils while peanut oil showed intermediate behaviour. Viscous regime was dominant during spreading of mineral and palm oils as compared to that of coconut oil. All the oils took longer period of time on rough surfaces than on smooth surfaces to relax to the same degree of wetting. Oils spreading on rough surfaces had to overcome the additional barrier due to asperities of the rough surface. Contact angle decreased with increase in roughness supporting the Wenzel's proposition. The decrease was significant for increase in roughness from 0.25 ?m to 0.50 ?m for all oils. However, the effect was negligible with further increase in roughness particularly for high viscosity oils. A spread parameter (?) is proposed to account for the variation of contact angle with surface roughness of the substrate and momentum diffusivity of the spreading liquid. The result suggested that low viscosity liquids exhibit improved wetting characteristics during spreading on rough surfaces. A model is proposed to estimate dynamic contact angles on substrates having varying surface roughness. © 2008 Elsevier Ltd. All rights reserved.Item Numerical simulation of laminar flow past a circular cylinder(2009) Rajani, B.N.; Kandasamy, A.; Majumdar, S.The present paper focuses on the analysis of two- and three-dimensional flow past a circular cylinder in different laminar flow regimes. In this simulation, an implicit pressure-based finite volume method is used for time-accurate computation of incompressible flow using second order accurate convective flux discretisation schemes. The computation results are validated against measurement data for mean surface pressure, skin friction coefficients, the size and strength of the recirculating wake for the steady flow regime and also for the Strouhal frequency of vortex shedding and the mean and RMS amplitude of the fluctuating aerodynamic coefficients for the unsteady periodic flow regime. The complex three dimensional flow structure of the cylinder wake is also reasonably captured by the present prediction procedure. © 2008 Elsevier Inc. All rights reserved.Item A comparative study on properties of porous friction course mixes with neat bitumen and modified binders(2009) Suresha, S.N.; George, V.; Ravi Shankar, A.U.R.This paper summarises details of the laboratory investigation on the effect of various binders on the performance and durability of porous friction course (PFC) mixes. Three different modified binders and neat bitumen were investigated for three different aggregate gradations at two predetermined binder contents. The performance was evaluated in terms of stone-on-stone contact condition, air voids, and hydraulic-conductivity of compacted PFC mixes. The structural durability was investigated based on aged abrasion loss and moisture susceptibility. The findings provide a better understanding of the effect of each binder type on the performance and durability of PFC mixes. Crown Copyright © 2008.