Faculty Publications
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Item Fatigue and Engineering Properties of Chemically Stabilized Soil for Pavements(Springer, 2013) Lekha, B.M.; Ravi Shankar, A.U.; Goutham, G.Soil stabilization is a technique to improve the weak soils and making them to meet certain requirements of the specific engineering projects. The type of soils available in Dakshina Kannada region of Karnataka State is laterite and Lithomarge clay. Its Plasticity Index is very high due to the presence of high percentage of silt and clay content. In the present investigation, an attempt is made to study the behaviour of laterite with and without adding chemicals. A chemical named Zycosoil, when added to water and mixed with soil alters its engineering properties that depend upon the type of the soil and dosage of chemical. These chemicals are liquid additives, which act on the soil to reduce the voids between soil particles and minimize adsorbed water in the soil for maximum compaction. In the present study, the effectiveness of Zycosoil in stabilizing the laterite soils of South Canara district is investigated through laboratory experiments. Various geotechnical properties are studied and correlations between different geotechnical properties and improvement in the soil properties with different percentages of chemical additions are derived. The important properties such as index properties, compaction characteristics, unconfined compressive strength parameters, California bearing ratio values and fatigue behaviour were studied. The results obtained indicate that there is an improvement in almost all properties with the addition of Zycosoil. © 2012 Indian Geotechnical Society.Item Partitioning studies of ?-lactalbumin in environmental friendly poly (ethylene glycol) - Citrate salt aqueous two phase systems(2013) Kalaivani, S.; Iyyaswami, I.Aqueous two-phase systems (ATPS) formed by polymer and salt have been utilized to enrich the desired biomolecule into one of the phase with higher yield and purity. The eco-friendly, biodegradable poly ethylene glycol (PEG) and different citrate salts were chosen as ATPS phase components to investigate the partitioning behavior of ?-lactalbumin (?-La). System factors and process parameters such as type and concentration of salt, molecular weight and concentration of PEG, pH, temperature and the effect of additives were studied and the results are discussed in detail. PEG 1000-tri-potassium citrate system yields high partition coefficient of 20 with a better yield of 98 % in the top phase. The addition of NaCl as an additive and acidic pH lowers the yield of ?-La in the top phase. Influence of phase volume ratio (V r) on partitioning was studied and found that the partition coefficient remains almost constant along the tie line. High yield was achieved at a V r of 3.5 at the tie line length of 50.63 (%, w/w). © 2013 Springer-Verlag Berlin Heidelberg.Item Influence of silica fume on the strength of betostyrene mixed concrete(2013) Sambo, A.G.; Deepak, T.J.; Mithun, B.M.The main objective of this paper is to determine the influence of silica fume (SF) on betostyrene mix concrete. Extensive experimentation was carried out to determine the influence of SF on the workability, compressive strength and flexural strength of concrete at constant water-binder ratio of 0.40 and SF additive of 0%, 5%, 10%, and 15%. For all mixes, slump test, compaction factor, compressive and flexure strengths were determined at 7, 14 and 28 days. The results showed that the compressive and flexure strengths increased with silica fume incorporation. This study comprehensively produced lightweight concrete and showed a rise in strength as in direct proportionality to the increase in silica fume. Workability fell to a rising amount of silica fume. © 2013 CAFET-INNOVA TECHNICAL SOCIETY.Item Preparation and antifouling properties of PVDF ultrafiltration membranes with polyaniline (PANI) nanofibers and hydrolysed PSMA (H-PSMA) as additives(Elsevier, 2014) Pereira, V.R.; Isloor, A.M.; Bhat, K.U.; A.F., A.F.Polyaniline (PANI) nanofibers were used as hydrophilic additives to study their effect on the performance of polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes. PVDF UF membranes were prepared by the phase inversion method with hydrolyzed polystyrene-co-maleic anhydride (H-PSMA) and PANI nanofibers as additives. PANI nanofibers were synthesized by rapid mixing reaction and were used as a hydrophilic modifying agent with varying concentrations (0-1.5 wt.%) in the membranes. The synthesized PANI nanofibers were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis. Hydrolyzed PSMA was prepared by the hydrolysis of PSMA and was used as a novel pore forming additive. The addition of PANI nanofibers into the membranes increased the membrane hydrophilicity, porosity, water uptake and permeability. The membranes also showed good antifouling nature during BSA (bovine serum albumin) filtration when compared to the pristine membrane without PANI nanofibers. Membrane with 1.0 wt.% PANI content showed highest permeability among the synthesized membranes. The membrane having highest permeability was subjected to heavy metal ion rejection which showed high rejection of 98.52% and 97.38% for heavy metal ions Pb2+ and Cd2+ respectively. © 2014 Elsevier B.V.Item Experimental study for the assessment of suitability for vegetation growth on coal mine overburden(Inderscience Enterprises Ltd., 2015) Ram Chandar, K.R.; Chaitanya, V.; Raghunandan, M.E.Owing to increased production and productivity of opencast coal mines, large amount of waste rock is removed and stacked in the form of waste dumps. Positive utilisation of such waste rock not only saves considerable dumping land but also reduces problem of maintaining stable and environmentally friendly dumps. One of the major utilisation of waste rock is to use it for vegetation. Therefore a systematic investigation to study the fertile characteristics of overburden waste rock for vegetation was conducted. Waste rock samples collected from an opencast coal mine dump in South India were used in the laboratory experiments. Observations showed the suitability of mine wastes for vegetation when supplemented with additives/nutrients - bottom ash, fly ash, lime stone powder and secondary sludge from sewage treatment plants (STPs) were considered for this purpose as additives. Results suggest that the mine-overburden supplemented with sewage waste (atleast 25% by volume) to be suitable for effective vegetation. © © 2015 Inderscience Enterprises Ltd.Item Production of layer by layer Zn-Fe compositional multilayer alloy coatings using triangular current pulses for better corrosion protection(Maney Publishing, 2015) Bhat, R.S.; Hegde, A.Multiple-layer coatings of Zn-Fe alloy having alternatively the same compositions have been developed galvanostatically on mild steel (MS) from a single plating bath using triangular current pulses. Thiamine hydrochloride (THC) and citric acid (CA) were used as additives. Multiple-layer coatings were developed under different conditions of cyclic cathode current density (CCCD) and number of layers. Cyclic voltammetry demonstrated that the addition of THC and CA improves the deposit character by increasing the Ni content (through suppressing the deposition of Zn) via preferential adsorption on the cathode surface. The corrosion behaviours of the coatings were evaluated by electrochemical AC and DC methods. The optimum multiple-layer coating, represented as (Zn-Fe)3.0/5.0/300, was found to exhibit about four to five times better corrosion resistance when compared with monolayer (Zn-Fe)3.0 alloy, developed from the same bath for the same duration. Distinct phase structures responsible for interface formation between successive layers (which changes alternatively) were confirmed by X-ray diffraction analysis. Better corrosion resistance afforded by multiple-layer coating was attributed to the increased specific surface area of the coating because of layering. A synergistic effect of both structural difference between layers and individual layer thickness is responsible for enhanced corrosion resistance of the multiple-layer coatings. The formation of multiple layers and corrosion mechanism were analysed by scanning electron microscopy. © 2015 Institute of Materials Finishing.Item Comparison of Stone Matrix Asphalt mixtures with polymer-modified bitumen and shredded waste plastics(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2016) Goutham, G.; Lekha, B.M.; Krishna, G.; Ravi Shankar, A.U.Stone Matrix Asphalt (SMA) is a gap-graded bituminous mixture characterised with its improved rut resistance and durability. It has comparatively higher proportion of coarse aggregates and binder mastic with bituminous binder and mineral filler. Drain down of mastic content at various stages of construction is a common issue with SMA, and generally, some fibre additives are used to stabilise the mixture or a modified bitumen is used as the binder material. In this study, shredded waste plastics (SWP) are used instead of other stabilising additives, to prepare SMA mixtures with conventional viscosity graded (VG) 30 bitumen. Mixtures were prepared with four different levels of SWP content, and another mixture without any stabilisers was also prepared using polymer-modified bitumen (PMB). Specimens were prepared in superpave gyratory compactor (SGC) for all mixtures at different bitumen contents to determine volumetric and Marshall properties, and optimum bitumen content (OBC) was calculated for each mixture. Tensile strength, moisture susceptibility, rutting resistance and fatigue behaviour were also determined for all mixtures at corresponding OBC. From the available results, the optimum level of SWP in SMA mixture was determined as 8% by weight of bitumen. The study showed that even though mixture with PMB performed the best, SMA with 8% SWP provided comparable results. Based on the present investigation, waste plastic in suitable dosage can be recommended in SMA, instead of a stabilising additive. © 2015 Informa UK Limited, trading as Taylor & Francis Group.Item Cooling Curve Analysis of Micro- and Nanographite Particle-Embedded Salt-PCMs for Thermal Energy Storage Applications(Springer New York LLC barbara.b.bertram@gsk.com, 2017) Sudheer, R.; Prabhu, K.N.In recent years, the focus of phase change materials (PCM) research was on the development of salt mixtures with particle additives to improve their thermal energy storage (TES) functionalities. The effect of addition of microsized (50 ?m) and nanosized (400 nm) graphite particles on TES parameters of potassium nitrate was analyzed in this work. A novel technique of computer-aided cooling curve analysis was employed here to study the suitability of large inhomogeneous PCM samples. The addition of graphite micro- and nanoparticles reduced the solidification time of the PCM significantly enhancing the heat removal rates, in the first thermal cycle. The benefits of dispersing nanoparticles diminished in successive 10 thermal cycles, and its performance was comparable to the microparticle-embedded PCM thereafter. The decay of TES functionalities on thermal cycling is attributed to the agglomeration of nanoparticles which was observed in SEM images. The thermal diffusivity property of the PCM decreased with addition of graphite particles. With no considerable change in the cooling rates and a simultaneous decrease in thermal diffusivity, it is concluded that the addition of graphite particles increased the specific heat capacity of the PCM. It is also suggested that the additive concentration should not be greater than 0.1% by weight of the PCM sample. © 2017, ASM International.Item Investigating the Utility of Iron Ore Waste in Preparing Non-fired Bricks(Springer India sanjiv.goswami@springer.co.in, 2017) Lamani, S.R.; Mangalpady, M.; Vardhan, H.Iron ore waste is a major problem for mine owners due to the difficulty involved in its storage, handling and other environmental related issues. An alternative solution to this is utilisation of iron ore waste (IOW) as some value added product in construction industry. An attempt has been made in this paper in examining the possibility of making non-fired bricks from iron ore waste with some additives like cement and fly-ash. Each of the additives were mixed with IOW in different ratios and different sets of bricks were prepared. The prepared IOW bricks were cured for 7, 14, 21 and 28 days and their respective compressive strength and percentage of water absorption were determined. The results show that IOW bricks prepared with 9% and above cement and with 28 days of curing are suitable for brick making and meet the IS specifications. It was also observed that the weight of the prepared bricks with 9% cement with 28 days of curing varies between 2.35 and 2.45 kg whereas the weight of compressed fire clay bricks varies from 2.80 to 2.89 kg. Results also show that the cost of bricks prepared with cement ranging from 9 to 20% is comparable to that of commercially available compressed bricks. © 2016, The Institution of Engineers (India).Item Experimental and theoretical study on dehumidification potential of clay-additives based CaCl2 composite desiccants(Elsevier Ltd, 2018) Hiremath, C.R.; Kadoli, R.; Katti, V.V.Transported clay suitable for pot making is used as desiccant carrier. Additives like saw dust and horse dung are considered in particle preparation. Particles nearly spherical in shape are prepared manually and are dried under shadow and subsequently the particles are dried at different temperatures. These burnt particles are characterized for pore volume and surface area. The BET test reveals that clay particles subjected to 500 °C possess higher pore volume but clay-horse dung particles exhibit higher surface area. Heat treated particles of clay with additives are impregnated with CaCl2 solution of 50% concentration. The ratio of desiccant water content to surrounding layer water content varies from 14.09 to 75.34 for CaCl2 based composite desiccants. One dimensional PGC mass transfer model for process air through burnt clay – additives - CaCl2 desiccant bed is adopted. The RMSE of measured and predicted results for reduction of moisture content from the process air by composite desiccant beds are in the range of 3.26–13.2%. © 2017 Elsevier Ltd