Faculty Publications
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Item Peak mooring forces in the horizontal interlaced multi-layered moored floating pipe breakwater(Society of Naval Architects of Korea, 2011) Mane, V.; Rajappa, S.; Rao, S.; Hegde, A.V.Present study aims to investigate the influence of relative breakwater width W/L (W=width of breakwater, L=wavelength), wave steepness Hi/gT2 (Hi=incident wave height, T=wave period) and relative wave height d/W (d=water depth) on forces in the moorings of horizontal interlaced multi-layered moored floating pipe breakwater (HIMMFPB) model. Studies were conducted on scaled down physical models having three layers of Poly Vinyl Chloride (PVC) pipes, wave steepness Hi/gT2 varying from 0.063 to 0.849, relative width W/L varying from 0.4 to 2.65 and relative spacing S/D=2 (S=horizontal centre-to-centre spacing of pipes, D=diameter of pipes). Peak mooring forces were also measured and data collected is analyzed by plotting non-dimensional graphs depicting variation of fs/?W2 (fs=Sea side Mooring force, ?=specific weight of water) & fl/?W2 (fl=Lee side Mooring force) with Hi/gT2 for d/W varying from 0.082 to 0.276 and also variation of fs/?W2 and fl/?W2 with W/L for Hi/d varying from 0.06 to 0.400. © SNAK, 2011.Item Variation of transmission coefficient and mooring forces with wave steepness on horizontal interlaced multilayered moored floating pipe breakwater with three layers(2011) Rajappa, S.; Pramod, K.; Hegde, A.V.; Rao, S.The paper presents the results of a series of physical model scale experiments conducted for the study of the transmission characteristics and mooring forces of horizontal interlaced, multi-layer, moored floating pipe breakwater, part of which have been presented in conferences. The studies are conducted on physical breakwater models having three layers of PVC pipes, wave steepness, Hi/L (Hi is incident wave height and L is incident wave length) varying from 0.01384 to 0.0661, relative width, W/L (W is width of breakwater) varying from 0.4 to 2.65 and relative spacing, S/D = 3 (S is horizontal spacing of pipes and D is diameter of pipe). The transmitted wave height is measured and data gathered is analyzed by plotting non-dimensional graphs depicting the variation of Kt (transmission coefficient) with Hi/L for values of d/W (d is depth of water) varying between 0.082 to 0.276 and Kt with W/L for values of d/W varying between 0.082 to 0.221. It is observed that Kt marginally decreases as Hi/L increases for the range of d/W between 0.082 and 0.221, considered in the present study. The maximum wave attenuation achieved with present breakwater configuration is 68%. The variation of measured mooring forces are analyzed by plotting non-dimensional graphs depicting fs/?w2 and fl/?W2 (fs and fl are the forces in the seaside and leeside moorings per unit length of the breakwater, ? is the unit weight of sea water) as a function Hi/L for various values of d/W. The mooring force parameter (fs /?W2) increases with an increase in wave steepness (Hi/L) for a range of d/W values studied. It is observed that for d/W = 0.082, maximum force parameter attained was 2.11E-04, and for d/W = 0.276 maximum force parameter was 6.88E-04. A similar trend is observed for leeside side force parameter. Hence, it clearly indicates the influence of d/W on f/?W2. © 2011 CAFET-INNOVA technical society. All right reserved.Item A study on loose material filled PVC props as an alternative to conventional wooden supports(2011) Pal, S.K.; Kedia, R.; Trivedi, A.K.This paper describes the research conducted to design new type of props using PVC pipe and loose particles (cohesive and non-cohesive) as fill material. The design of the props is such that load is applied only to the inner core, of which a part of it is borne by the PVC because of the friction between inner and outer pipe. Rest of the load is transferred to the core, which pressurizes the pipe from inside. The reasoning behind constructing such props is that a pipe that is internally pressurized will be more rigid towards bending and hence take more load. This paper discusses experimental research work carried out on small as well as large scale props by varying L/D ratio (fixed in case of large scale props) and the type of fill material (cohesive and noncohesive) for testing their ultimate strength by loading them in different manners.Item Wave steepness and relative width: Influence on transmission coefficient of horizontal interlaced, multilayered, moored floating pipe breakwater with five layers(2011) Rajappa, S.; Hegde, A.V.; Rao, S.; Channegowda, V.This paper presents the results of a series of physical model scale experiments conducted to determine the transmission characteristics of a horizontal interlaced, multilayered, moored floating pipe breakwater. The studies are conducted on physical breakwater models having five layers of PVC pipes. The wave steepness (H i/gT 2, where H i is incident wave height, g is acceleration due to gravity, and T is time period) was varied between 0.063 and 0.849, relative width (W/L, where W is width of breakwater and L is the wavelength) was varied between 0.4 and 2.65, and relative spacing (S/D, where S is horizontal centre to centre spacing of pipes and D is the diameter of pipes) was set equal to 2. The transmitted wave height is measured, and the gathered data are analyzed by plotting nondimensional graphs depicting the variation of K t (transmission coefficient) with Hi/gT 2 for values of d/W (d is depth of water) and of K t with W/L for values of H i /d. It is observed that K t decreases as H i /gT 2 increases for the range of d/W between 0.082 and 0.139. It is also observed that K t decreases with an increase in W/L values for the range of H i /d from 0.06 to 0.40. The maximum wave attenuation achieved with the present breakwater configuration is 78%.Item Thermodynamic miscibility and thermal and mechanical properties of poly(ethylene-co-vinyl acetate-co-carbon monoxide)/poly(vinyl chloride) blends(John Wiley and Sons Inc, 2015) SelvaKumar, M.; Mahendran, A.; Bhagabati, P.; Anandhan, S.This paper reports the miscibility and thermal and mechanical properties of solution cast binary blends of poly(ethylene-co-vinyl acetate-co-carbon monoxide) (EVACO) and poly(vinyl chloride) (PVC). The composition of these blends was varied from 10:90 to 90:10 of PVC/EVACO (w/w %). Fourier transform infrared spectroscopy revealed an extensive intermolecular attraction between the blend components, which accounts for their mutual solubility. The differential scanning calorimetry study revealed that the blend components are miscible with each other in all proportions as they exhibited a single glass transition temperature. Tensile strength, moduli, and thermal stabilities of these blends significantly improved with increasing proportion of PVC. © 2014 Wiley Periodicals, Inc.Item Synthesis and characterization of novel sulfanilic acid-polyvinyl chloride-polysulfone blend membranes for metal ion rejection(Royal Society of Chemistry, 2016) Nayak, V.; Jyothi, M.S.; Balakrishna, R.G.; Padaki, M.; Isloor, A.M.Near-complete removal of heavy metals, namely Cd(ii), Cr(vi) and Pb(ii), has been attempted by a membrane purification process using a blend of modified polyvinyl chloride (PVC) and polysulfone (PSf), prepared by the diffusion induced phase separation (DIPS) method. The prepared novel material was characterized by NMR, ATR-IR spectroscopy and DSC. The sulphonyl groups incorporated into PVC enhance the hydrophilicity and are substantiated by water uptake, contact angle (CA) and flux studies. The obtained properties of the blend membrane like increased surface roughness and porosity are observed from AFM and SEM analysis. An enhanced rejection of ?95% which is about 1.15, 1.41 and 1.37 times better than the commercially available NF 270 membrane was observed, for Cd(ii), Cr(vi) and Pb(ii) respectively. The work was further extended to study the antifouling property and the interference of other existing metal ions on the performance. An improved antifouling property with 98.5% rejection for bovine serum albumin (BSA) and a 75.6% flux recovery ratio (FRR) was achieved. The study gains significance in exploring the incorporation of sulphonyl groups in to polymers, to enhance membrane performance. © The Royal Society of Chemistry 2016.Item Ductility and Flame Retardancy Enhancement of PVC by Nanostructured Fly Ash(Springer editorial@springerplus.com, 2019) Patil, A.G.; Mahendran, A.; SelvaKumar, M.; Anandhan, S.Fly ash (FA) obtained from a coal-fired local thermal power station was converted into a nanostructured material by mechano-chemical activation using a high energy planetary ball mill. Contact angle measurements and FTIR spectroscopy confirmed the surface modification of mechano-chemically activated FA (MCA-FA). Subsequently, a solution casting method was used to prepare poly(vinyl chloride) (PVC) matrix composites with varying amounts of fresh FA and MCA-FA. Mechanical testing results of the composites revealed that incorporation of fresh FA in PVC resulted in a higher tensile strength with brittle failure; addition of MCA-FA to PVC resulted in higher elongation at break values while retaining the ductility of the PVC. We have proposed a plausible mechanism explaining the influence of fresh FA and MCA-FA on the mechanical behavior of these composites. As fresh FA and MCA-FA contain basic oxide materials, they tend to improve the fire retardancy of PVC even at a very small loading. Overall, the nanostructured MCA-FA could find application as a filler in PVC-based products. © 2016, Springer Science+Business Media Dordrecht.Item Investigations on thermo-mechanical properties of organically modified polymer clay nanocomposites for packaging application(SAGE Publications Ltd, 2021) Sudhakar, Y.N.; Muthu, M.; Bhat, D.K.Eco-friendly packing polymer materials are in the spotlight but, lack of new biodegradable polymers either natural or synthetic is yet to establish the market more competitively. So, in the present work, clay as a nano-filler is embedded and organically modified in some synthetic and natural polymers which are well established commercially to enhance their biodegradability. The impact of clay on the properties of synthetic polymers namely, poly(methyl methacrylate) (PMMA), poly(vinyl chloride) (PVC), poly(vinyl acetate) (PVAc) and natural polymer cellulose acetate butyrate (CAB) was studied. Results from differential scanning calorimetric (DSC) showed a decrease in the glass transition temperature of organically modified polymer clay nanocomposites (PCC) than pure polymers. Scanning electron microscopy (SEM) displayed a uniform surface with small-sized crystallites distributed on the polymer surface. X-ray diffraction (XRD) spectra revealed the formation of enhanced intercalated structures in PCC. Furthermore, FTIR studies showed that the interlayer bonding (Si–O bands) of pure clay is deformed in PCCs. The tensile strength of PCC increased with an increase in organo-clay loading. This unique mechanical behavior is due to the agglomeration of organo-clay particles. Finally, the biodegradation studies revealed enhanced hydrolytic degradation in PCC than pure polymers. Hence, these PCCs are environmentally friendlier than their pure synthetic polymers without significant compromise in their properties, which makes it suitable for packaging industries. © The Author(s) 2020.Item Enhancement and investigation of biodegradability of poly (methyl methacrylate) and poly (vinyl chloride) by blending with biodegradable polymer(Springer Science and Business Media Deutschland GmbH, 2023) Sudhakar, Y.N.; Muthu, M.; Bhat, D.K.Presently, society needs an eco-friendlier alternative for non-biodegradable polymers, nonetheless, synthetic polymers have established the market because of cost and easy to manufacture. To address the challenge of reducing the lifetime of degradation of these polymers, the scope of blending natural biopolymers is effective. This paper focuses on confirming the effectiveness of biodegradation in the molecular level of polymer blends between synthetic polymers and biopolymers. The synthetic polymers such as poly (methyl methacrylate) (PMMA) and poly (vinyl chloride) (PVC) were blended with varying compositions of biodegradable cellulose acetate butyrate (CAB). Using dimethylformamide (DMF) the films of PMMA/CAB, PVC/CAB blends were prepared by the solution casting method. Four different methods for studying biodegradability of these blends, namely soil burial test, enzymatic degradation, activated sludge degradation followed by microbial degradation were performed. The confirmation of degradation was done by NMR, FTIR, and Gel Permeation Chromatography (GPC) studies. Moreover, degradation analyses were determined by the weight loss method. Sufficient biodegradability was shown with an increase in CAB content in the blend. This work provides an approach for bringing about the degradation of synthetic polymers without much compromise on their properties. Also, the type of microorganisms that effectively degrades these polymer bends can be known. © 2022, The Author(s).