Department of Mechanical engineering
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Item Bio-hydrogel for Prolonged Controlled Gastro-retentive Drug Dispenser(IEEE, 2019) Belgamwar, Sachin U.; Roy, AniruddhaA carbohydrate based polyacrylamide (Paam) modified with guar gum (GG) bio-hydrogel was developed for triggered, controlled gastro-retentive drug dispenser (GRDD) application. Temperature was applied as external stimuli and acidic medium (pH4) was used to release the drug from gel network. The release phenomenon was observed until 60 hours to understand the suitability for prolonged gastro retentive drug dispensing vehicle. The cytotoxicity was assessed by XTT assay with MCF-7 cell line.Item Experimental Investigation of Pool BHT Performance of R-141b on Micro/Nano-Porous Copper Coating Prepared by a Two-stage Electrodeposition Method(IEI Conferences, 2021) Belgamwar, Sachin U.Pool boiling heat transfer (BHT) of R-141b on po-rous Cu coated heating surface was experimentally studied. Porous Cu coating was fabricated on a plain Cu heating sur-face through a two-stage electrodeposition method. Surface characterization of Cu coating confirmed the successful syn-thesis of micro/nano-porous Cu coating. Experimental re-sults showed that the Cu coated heating surface introduced a significant enhancement in heat transfer coefficient (HTC) and a great reduction in wall superheat compared to the plain Cu surface. The maximum enhancement in HTC for the Cu coated heating surface was approximately 53% compared to the uncoated heating surface. This is believed to have re-sulted from the increase in active surface area, nucleation site density and cavitation activity owing to the microporous structure of Cu coating. Obtained results showed that the mi-croporous Cu coated heating surface could be employed in modern heat transfer applications.Item Fabrication of aluminum coatings via thermal evaporation technique for enhancement of pool boiling performance of R-600a(Elsevier, 2022) Belgamwar, Sachin U.In this study, thermal evaporation technique was scrutinized experimentally to fabricate Al coatings on plain aluminum heating surface and improve the pool boiling heat transfer (BHT) performance of R-600a. The Al coatings were fabricated by varying the coating thickness (100 nm, 150 nm, 200 nm and 250 nm). Pool BHT performance of R-600a on a plain aluminum and four Al coated heating surfaces (Al_100 nm, Al_150 nm, Al_200 nm and Al_250 nm) was investigated at a constant saturation temperature of 10 °C. All data were taken at heat fluxes ranging from 9.39 kW/m2 to 74.98 kW/m2. Decrement in the wall superheat was recorded with the increment in the coating thickness, and maximum decrement was observed for the surface with 250 nm thick coating. It was further observed that with the increment of the coating thickness, the HTC of the Al coated heating surfaces was increased than the plain aluminum heating surface. The maximum enhancement in HTC for the Al_250 nm heating surface was 51.62% higher than the plain aluminum heating surface.Item A brief overview of magnetic metal - carbon nanocomposites(IAEA, 2022) Belgamwar, Sachin U.Metal–carbon nanomaterials and nanocomposites are advanced materials that can fulfill modern technologies challenges. In magnetic metal-carbon nanocomposites, the carbon allotropes and metals can interchange as nanofiller and binding matrix. One of the primary concerns with magnetic materials is their structural, thermal, and chemical stability. The composition, temperature, and fabrication method of metal-carbon nanomaterials are the significant factors that can influence their performance. The carbon allotropes such as graphene, CNT, and fullerene can be nanofillers for a metallic magnetic matrix to improve their overall performance. In addition, the magnetic monometallic (Fe, Co, Ni) and bimetallic (Fe–Co, Fe–Ni, Fe–Cu, Co–Cu, and Co-Ni alloys) nanofillers with carbon matrix can also be a combination for metal-carbon nanocomposites. Among these combinations, the carbon allotropes reinforcement in the metal matrix attracts researchers due to its low-cost, facile, and industrially scalability with excellent tribo-mechanical strength, high thermo-electrical properties, and adequate corrosion resistance. These materials are used in applications such as hydrogen fuel cells, microelectronic, bio-medical devices and implants, solid lubricants, catalysts, etc. This review article discusses the fabrication method, reinforcement patterns, compositions, magnetic properties of metal carbon nanocomposites, and future applicationsItem Pool Boiling Heat Transfer Performance of R-134a on Microporous Al Surfaces Electrodeposited from AlCl3/Urea Ionic Liquid(Springer, 2022-12) Belgamwar, Sachin U.Development of smart heating surfaces to enhance the performance of pool boiling heat transfer (BHT) has great significance in pool boiling applications. This paper presents the results of a study of improved pool BHT performance of R-134a on horizontal Al surfaces with microporous coating (diameter = 9 mm) at saturation temperature. Microporous Al coatings were fabricated by electrodeposition using AlCl3/urea ionic liquid (IL). The effect of various electrolyte temperatures (30°C, 40°C, 50°C, and 60°C) on the morphology, microstructure, porosity, thickness, and surface roughness of Al coatings was investigated. The pool BHT experiments were performed for increase in the heat flux, varying from 9.51 kW/m2 to 75.14 kW/m2. For the microporous Al coating electrodeposited at an electrolyte bath temperature of 30°C, 40°C, 50°C, and 60°C, the heat transfer coefficient (HTC) value was increased by 58%, 75%, 92%, and 109%, respectively, compared with the bare Al surface. The differences in the HTC augmentation for Al-coated surfaces can be explained by variations in the thickness of the microporous structure and in their surface characteristics such as porosity and surface roughness.Item An experimental study on pool boiling of R-600a on Cu@Gr composite-coated patterned surfaces(Springer, 2022-12) Belgamwar, Sachin U.Two-step electro-co-deposited Cu@Gr composite coatings on patterned surfaces (HSI, HSII, HSIII and HSIV) were used to improve the pool boiling heat transfer performance of R-600a. The pattern design was varied to vary the geometrical parameters, which affected the heat transfer area, capillary action and stable active nucleation sites. These copper patterned surfaces of four different designs (PI, PII, PIII and PIV) were fabricated using wire EDM method, and copper patterned surfaces were integrated with microporous Cu@Gr composite coatings. The experimental results showed that the heat transfer coefficient (HTC) augmented with the increase in heat transfer area. The HTCs of all the Cu@Gr composite-coated patterned surfaces were significantly improved compared with those of the bare Cu surface. The maximum BHT coefficient ratio (hER) belonging to HSI, HSII, HSIII and HSIV was 2.86, 2.99, 3.15 and 3.36, respectively. The improvement in pool BHT can be attributed to the integration of patterned surfaces and microporous Cu@Gr composite coatings contributed to the significant increase in active nucleation sites, more liquid replenishment for surface rewetting and increased heat transfer area.Item Characterization of quenched MD simulated porous carbon electrodes for supercapacitors(Elsevier, 2023) Belgamwar, Sachin U.Energy storage devices are playing a significant role in reducing the harmful effects of global warming. Automobile manufacturers are already shifting towards electric vehicles (EVs) in order to curb vehicular pollution. One of the significant drawbacks of the current EV batteries lies in their power density which limits their application. Supercapacitors are a category of energy storage devices that keep excellent specific power capacity and can be used in a hybrid setup with Li-ion batteries in order to make EVs with longer life and rapid acceleration. Electrode porosity in supercapacitors performs a major role in defining their energy and power density. This work explores the quenched molecular dynamics (QMD) simulations followed by thorough characterization for understanding the bimodal pore size distribution (combination of micro- & mesopores) of a porous electrode structure for maintaining a high energy and power density. We performed simulations at various quench rates on porous carbon structures ranging from 600 K/ps to 5 K/ps. Once the porous structures obtained room temperature (300 K), we characterized it for its pore sizes that allow ions to move in and out of the pores during charging and discharging, respectively. The interconnected channeling method has been developed to identify the channel throats and their lengths for different cases of quench rates. Direct output of this study will help experimentalists in fabricating tunable porosity in order to achieve high energy density while maintaining a relatively good power density of supercapacitors.Item Pool boiling of R-134a on ZnO nanostructured surfaces: and heat transfer(CRC Press, 2023) Belgamwar, Sachin U.An experimental study was carried out to investigate the pool boiling performance of R-134a onZnO nanostructured heating surfaces. ZnO nanostructured heating surfaces were fabricated by the thermal evaporation technique followed by heat treatment. Nanostructured ZnO thin films were applied on the bare aluminum heating substrate, furthermore pool boiling performance was carried out with R-134a. Experimental data were recorded at heat fluxes ranging from 9.37 to 72.23 kW/m2k. It was found that with a rise in the thickness of nanostructured ZnO thin film, the wall superheat was decreased and the maximum decrement in wall superheat was observed for nanostructure ZnO thin film with 300 nm thickness. It was also observed that the heat transfer coefficient (HTC) of the ZnO nanostructured surfaces increased with the rise in thickness of coating. The highest value of HTC for ZnO-300 surface was61% greater than the bare Al heating surface.Item Pool boiling heat transfer of R-600a on plain copper and Cu@GPL porous composite coating surfaces(CRC Press, 2023) Belgamwar, Sachin U.In this work, nucleate pool boiling experiments were performed on the plain copper and graphene nanoplatelets reinforced Cu matrix (Cu@GPL) porous composite coatings using saturated refrigerant R-600a. The Cu@GPL porous composite coatings were fabricated by a two-step electrodeposition technique. Copper sulfate pentahydrate as a source of Cu and graphene nanoplatelets (GPL) as reinforcing element were used as starting materials for fabrication of Cu@GPL porous composite coatings. The effect of coating parameters such as surface roughness, coating thickness, and porosity on the heat transfer coefficients (HTCs) and boiling characteristics of refrigerants was investigated and presented in detail. The heat transfer coefficient of Cu@GPL porous composite coating was enhanced approximately 2.36 times than that of the plain copper heating surface. The augmentation in the HTCs is primarily due to an increase in surface roughness, coating thickness, porosity and active nucleation of the Cu@GPL porous composite coatings.Item Atomistic analysis of the effect of cholesterol on cancerous membrane protein system: unfolding and associated resistance stresses under strain(Taylor & Francis, 2023-05) Rao, Venkatesh K.P.; Belgamwar, Sachin U.The low-cholesterol cancerous environment can affect the biophysical behaviour of transmembrane proteins. It is difficult to experiment and measure the dynamics of membrane protein systems when cholesterol concentration is decreasing. In this work, atomistic approach is adopted to investigate the transmembrane protein behaviour during lipid-bilayer separation under strain at different cholesterol concentrations. Finding shows that the decreasing cholesterol across membrane protein system leads to an increase in area-per-lipid and average tilt angle by 6.4% and 62.6%, respectively with decreased order parameter. This observation indicates that the decreased cholesterol concentration in a cancerous environment hinders the bonding and compactness of membrane protein system. Stretching and unfolding of protein were observed during bilayer separation and the resistance stresses decreased by 68.01% for decreasing cholesterol. The cholesterol molecules observed to be bonded with proteins. The investigation revealed that the cholesterol is an important constituent of membrane that impedes the diffusion and resist the detachment of protein at high concentration. Thereby, the transmembrane proteins can retain end terminals positions across the membrane and resist functional failure. This study showed that decreased cholesterol concentration causes significant changes in the biophysical behaviour of the membrane protein system that could trigger the mechanosensitivity of transmembrane proteins under mechanical perturbation.