Faculty Publications

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    A comparison of the effects of microwave versus conventional drying on the mechanical properties distribution of dried green porcelains
    (2008) Hemanthakumari, P.N.; Satapathy, L.N.
    The effect of fast microwave drying of electroporcelain insulator component was studied by determining the reliability parameter. The Weibull modulus was calculated using the three-point bend strength data of a large number of green samples which were dried using microwave energy. The results were compared with those obtained by conventional drying methods. It was observed that in most cases, microwave-dried components yielded higher Weibull modulus than their conventionally dried counterparts. A high modulus value of >15 was achieved on the microwave-dried samples. The analysis of the result was useful in understanding the fast drying process in ceramics. © 2008 The American Ceramic Society.
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    An empirical model for the estimation of moisture ratio during microwave drying of plaster of Paris
    (2008) Ganesapillai, M.G.; Iyyaswami, I.; Murugesan, T.
    The drying characteristics of plaster of Paris (POP) under microwave irradiation were studied for different shapes of materials through various drying parameters like microwave power, initial moisture content, and drying time. An empirical model for the estimation of moisture ratio was developed using the drying kinetic data of POP. Further, the experimental data on moisture ratio of POP for different operating conditions were fitted with the nine basic drying model equations. Based on the observations, the constants and coefficients of the literature models were rewritten in the form of Arrhenius and logarithmic expressions considering microwave power as input variable. Fifty-eight new model expressions were derived by changing the constants and coefficients and tested using the present experimental data. From the analysis of RMSE, ?2, and EF parameters for the derived models, a suitable empirical model (Model No. 55, RMSE = 0.0874; ?2 = 0.0020; EF = 0.9999) was established to represent the present experimental data on microwave drying of POP.
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    Characterization and process optimization of microwave drying of plaster of Paris
    (2008) Ganesapillai, M.G.; Iyyaswami, I.; Murugesan, T.
    The changes in the characteristics of plaster of Paris (pop) during drying operation under microwave irradiation conditions, namely surface morphology, effective moisture diffusivity, and absorption of microwave, were studied. The drying characteristics and kinetics of the process during microwave drying of plaster were studied for rectangular-faced cuboids (80 × 70 × 15, L × B × H in mm) through various drying parameters like microwave power input, initial moisture content, and drying time. Further, the experimental data on moisture ratio of plaster for different operating conditions were obtained and the optimization of the microwave drying process parameters was performed with response surface methodology (RSM) by considering all the above-said independent variables. Based on the RSM analysis, the optimum values of the process variables were obtained as: initial moisture content (A) 60%; microwave power input (B) 180 W; and drying time (C) 480 S.
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    Moisture diffusivity and energy consumption during microwave drying of plaster of Paris
    (2010) Ganesapillai, M.G.; Iyyaswami, I.; Miranda, L.R.; Murugesan, T.
    The drying characteristics of plaster of paris (POP) under microwave conditions at different microwave power input, initial moisture content, sample thickness and drying time were studied. Further the experimental data on moisture ratio of POP for different operating conditions were obtained and calculations were made using nine basic drying model equations. The appropriate model with modified constants and coefficients to represent the drying kinetics of POP was found through the analysis of the statistical analysis. The effective moisture diffusivity of the drying process was also computed for different experimental conditions and a relationship between the drying rate constant and the effective moisture diffusivity was obtained. The energy consumption for microwave drying of plaster of paris at different experimental conditions were also computed. © 2010 The Berkeley Electronic Press. All rights reserved.
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    Synthesis and biological evaluation of aminoketones
    (2010) Sankappa Rai, U.; Isloor, A.M.; Shetty, P.; Isloor, N.; Malladi, S.; Fun, H.-K.
    A three-component Mannich reaction of different ketones with aromatic aldehydes and different amines in microwave irradiation under solvent free condition afforded corresponding ?-amino carbonyl compounds in excellent yields. This method proved as a novel and improved modification of the reported three-component Mannich reaction in terms of milder reaction conditions, reaction times, clean reaction profiles, very small quantity of catalyst and simple workup procedure. Newly synthesized ?-aminoketones were characterized by spectral studies. Structure of compound 4a was also confirmed by single-crystal X-ray analysis. All the compounds were screened for their antimicrobial activity by MIC method. Few of the molecules were found to be biologically potent. © 2010 Elsevier Masson SAS. All rights reserved.
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    An optimization study of microwave assisted extraction of oil from oily sludge using response surface methodology
    (CAFET INNOVA Technical Society cafetinnova@gmail.com 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2014) Kumar, B.; Raj Mohan, B.
    Petroleum oily sludge, a hazardous waste, generated by the refineries and at the production sites in huge quantities comprises of a mixture of petroleum hydrocarbons, asphaltenes, long chain paraffinic wax, waste water, sediments and metals. The present study is aimed to recover oil from the petroleum oily sludge using n-heptane as the solvent in microwave assisted solvent extraction process and to optimize the process variables for the recovery of oil from the oily sludge. The simultaneous effects of process variables such as irradiation time (2 - 10 minutes), solvent to sludge ratio (40 – 80 wt %), reactant volume (100 – 300 ml) and microwave power (80 – 400 W) on the recovery of oil were evaluated. A central composite design (CCD) and response surface methodology (RSM) were used for the optimization of the extraction process. Based on the CCD, quadratic model was developed to correlate the extraction process variables with the responses and the model was analysed using appropriate statistical method (ANOVA). Optimization of process variables shows that the maximum recovery of oil was about 88.6% at 100 ml of reactant volume with microwave power output of 351 W at 6.5 minutes of irradiation time with 58.99% of nheptane to sludge ratio. © 2014 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Joining of Inconel-625 alloy through microwave hybrid heating and its characterization
    (Elsevier Ltd, 2015) Badiger, R.I.; Narendranath, S.; Srinath, M.S.
    Joining of bulk metals using microwave energy is being explored as a new processing method in the era of high technology applications. The present work investigates the results of on-going project in which joining of Inconel-625 alloy has been effectively carried out through microwave hybrid heating. Characterization of the microwave developed joints is done through SEM, XRD, UTM and Vicker's microhardness tester. The microstructural analysis through scanning electron microscope exhibits a fully fused weld interface free from interfacial cracks. XRD study reveals the formation of carbides of Ni, Cr and Mo in the joint interface. The average Vicker's microhardness in the joint region observed was 360 ± 20 Hv. Assessment of tensile strength shows an ultimate tensile strength of 328 MPa with 9.04% elongation. Further the fractured joints are subjected to fractography study which possibly reveals a mixed mode fracture. © 2015 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.
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    Model generation and process optimization of microwave-assisted aqueous extraction of anthocyanins from grape juice waste
    (Blackwell Publishing Inc. subscrip@blackwellpub.com, 2017) Venkatramanan, V.; Shanmugam, S.; Arulvel, A.
    The microwave-assisted extraction of anthocyanins from grape juice waste was investigated in this study. The optimization was implemented using response surface methodology with Box–Behnken design and genetic algorithm (GA). Anthocyanins from grape juice waste were extracted under various microwave power (100–600 W), exposure time (1–5 min) and solvent/solid ratio (10–50 ml/g). The total monomeric anthocyanin yield was considered as the response for optimization experiments. The results indicated that the quadratic model was significant for the chosen response at p <.0001. The analysis of variance and response surface plots showed a significant interaction of all the selected independent variables over anthocyanin extraction process. The maximum anthocyanin yield of 1.31881 mg/g of grape juice waste was predicted by response surface methodology, and the prediction was improved to 1.32244 mg/g of grape juice waste by GA. A confirmatory experiment performed under optimum conditions showed anthocyanin yield of 1.3215 mg/g of grape juice waste. Hence, this model was successful in predicting anthocyanin extraction from grape juice waste under microwave-assisted extraction conditions. Practical application: Anthocyanin pigments find a broad range of implementation as food colorants, antioxidants, and anticancerous agents. The waste residue obtained during grape juice production and processing is also rich in anthocyanins and can be used as an alternative source for anthocyanin extraction. This study exploits the use of grape juice waste for anthocyanin extraction, and it can be the best way of waste management and cost reduction in grape juice production units. © 2016 Wiley Periodicals, Inc.
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    Evaluation of mechanical properties for nickel based steel produced by metal injection moulding and sintered through conventional and microwave method
    (Italian Association of Chemical Engineering - AIDIC aidic@aidic.it, 2018) Veeresh Nayak, C.; Ramesh, M.R.; Desai, V.; Kumar Samanta, S.K.
    Metal injection moulding is a near net shape manufacturing technique. It developed from traditional plastic injection moulding and powder metallurgy process. The process involved mixing of metal powder and binder, injection moulding, debinding and sintering of moulded samples. Microwave process indicated critical consideration towards exceptional highlights, regards to, heating and sintering the various grouping of metals with the huge preferred perspective, control rate, and similarity, low ecological dangers. The samples consist of SS316L+WC-CrC-Ni metal powder and binders, low-density polyethylene (LDPE), paraffin wax (PW), stearic acid (SA) and polyethylene glycol (PEG 600). In the present study, the injection moulded green parts are exposed to high-intensity microwave fields operates at a frequency of 2.45 GHz. for sintering of MIM samples. The whole process time of the microwave-assisted sintering was remarkably less than conventional sintering. The sintering of SS316L+WC-CrC-Ni compact showed better results than those produced by sintering with conventional heating. The current study evaluates the effect of the conventional and microwave sintering on mechanical properties. © © 2018, AIDIC Servizi S.r.l.
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    Influence of microwave hybrid heating on the sliding wear behaviour of HVOF sprayed CoMoCrSi coating
    (Institute of Physics Publishing helen.craven@iop.org, 2018) Prasad, C.D.; Joladarashi, S.; Ramesh, M.R.; Srinath, M.S.; Channabasappa, B.H.
    CoMoCrSi superalloy powder (Tribaloy-T400) consists of intermetallic laves phase and primary eutectic phase of Co-rich solid solution. Processing of Tribaloy-T400 powder is carried out through high-energy ball milling (HEBM) technique to obtain a higher volume fraction of intermetallic laves phases. The feedstock is sprayed using high-velocity-oxy-fuel (HVOF) process on titanium grade-15 substrate. The coating microstructure is homogenized by microwave hybrid heating technique. Characterization of feedstock, as-sprayed and microwave fused coatings is done by using Scanning Electron Microscopy (SEM), Energy dispersive spectroscopy (EDS) and x-ray Diffraction (XRD). Porosity, surface roughness, microhardness, and bond strength are measured. Adhesive wear behavior of the coatings under the dry sliding condition is evaluated at an applied load of l0 and 20 N and temperature of 200, 400 and 600 °C Fused coating exhibit higher wear resistance than the as-sprayed coatings and substrate. The hard intermetallic laves phases which are amorphous (bulk metallic glass) in nature strengthen the coating at high temperatures. © 2018 IOP Publishing Ltd.