Browsing by Author "Shivamurty, B."

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An Investigation on the Acetone and Ethanol Vapor-Sensing Behavior of Sol-Gel Electrospun ZnO Nanofibers Using an Indigenous Setup
(American Chemical Society, 2023) Prabhu, N.N.; Shivamurty, B.; Anandhan, S.; Rajendra, B.V.; Jagadeesh Chandra, J.C.R.; Srivathsa, M.
The calibration is essential for accuracy, repeatability, and continuous trouble-free operation of gas sensors with safety. Most gas sensors are fabricated using metal oxide nanomaterials in different structures such as films, coating, or nanofibers. Therefore, a device in the sensor manufacturing industry is necessary to test, calibrate, and optimize metal oxide structures. In this point of view, a simple device is developed to test and estimate the sensing response, response time, and recovery time of nanostructures. The sol-gel method was used to produce nanofibers through electrospinning. An average fiber diameter of 245 nm was obtained after pyrolysis at 600 °C. The structure and composition of ZnO nanofibers are confirmed by X-ray diffraction, scanning electron microscopy, and Brunauer-Emmett-Teller. The trials were taken using ZnO nanofibers in the presence of acetone and ethanol vapor, and the results were reported. High response (31.74), rapid response (40 s), and recovery (30 s) times have been achieved for ethanol gas to 50 ppm concentration test gas at an optimal temperature of 260 °C. The results obtained from the trials are compared with the literature results, which are in line with the values presented by the various researchers. Due to the low cost, easy maintenance, and accuracy, this device is recommended in metal oxide sensor development industries and laboratories. © 2023 The Authors. Published by American Chemical Society
Effect of Ni doping on the acetone vapor sensing performance of ZnO nanofibers
(Elsevier Ltd, 2025) Prabhu, N.N.; Shivamurty, B.; Anandhan, S.; Rajendra, B.V.; Kulkarni, S.D.
Nickel-doped zinc oxide (NiZ) nanofibres (NFs) were fabricated using sol-gel electrospinning (ES) technique followed by pyrolysis from an aqueous solution of polyvinyl alcohol/zinc acetate/nickel acetate tetrahydrate. The morphology of the NiZ NFs was analyzed using Scanning Electron Microscopy (SEM), which revealed a uniform and well-defined fibrous structure. X-ray diffraction (XRD) results indicated complete removal of the organic phase from NiZ NFs during pyrolysis. The structural analysis confirmed the incorporation of Nickel (Ni) into the Zinc oxide (ZnO) lattice without altering its wurtzite crystal structure. The optical properties and bandgap variations were evaluated using UV–visible spectroscopy, which indicated a bandgap narrowing with increasing Nickel doping. The Photoluminescence (PL) spectroscopy confirmed the presence of defect states and recombination processes in the NFs. The gas sensing performance was investigated by measuring the response to various analytes at a concentration of 50 ppm with varying operating temperatures. The results indicated that the highest response was observed for 5 w% NiZ NFs towards acetone vapors. The response and recovery time were recorded at 80 s and 60 s. The enhanced sensitivity is attributed to the optimal doping concentration, which significantly improves the surface reaction and charge carrier mobility. © 2024 The Authors
Influence of nano-aluminum-hydroxide on tribological, mechanical and flammability properties of E-glass fabric/epoxy multi-layered laminates
(Huthig GmbH, 2014) Shivamurty, B.; George, G.; Bhat, K.U.; Anandhan, S.
E-glass fabric/nano aluminum hydroxide (ATH)/epoxy composites were prepared by manual lay-up and compression molding. An image processing tool was used to quantify fineness of dispersion of nano-ATH particles in epoxy. Fourier transform infrared (FTIR) spectroscopy was used to understand the interaction between nano-ATH and epoxy. Mechanical properties, sliding wear resistance and fire retardance of these composites improved upon addition of nano-ATH. The composite containing 0.125 wt% of nano-ATH exhibited optimum mechanical properties and low specific wear rate.
Machining characteristics of nanocomposites
(2011) Umashankar, K.S.; Gangadharan, K.V.; Desai, V.; Shivamurty, B.
Nanocomposites were prepared with Al/Al-Si alloys (LM 6 and LM 25) as matrix and multi wall carbon nanotube (MWNT) of 0.25, 0.5, 0.75, 1.0 and 1.5 wt. % as reinforcement through powder metallurgy (PM) followed by sintering and hot extrusion techniques. Fabricated nanocomposites were machined on a Panther 1530/1650 lathe by using tungsten carbide tool. Recurrence quantification analysis (RQA) was used to study the machining characteristics by using cutting force signal stability. Highest value ofdeterminism (DET-one of the RQA parameter) was observed for 0.5 wt.% MWNT reinforced Al and Al-Si nanocomposites. This attributes better machining characteristic due uniformity of the signals. Also it is observed better mechanical properties at 0.5 wt.% reinforced nanocomposite and further reinforcement deteriorate the machinability and mechanical properties. © 2011 VBRI press.
Mechanical and sliding wear properties of multi-layered laminates from glass fabric/graphite/epoxy composites
(Elsevier Ltd, 2013) Shivamurty, B.; Bhat, K.; Anandhan, S.
Multi-layered laminates of bi-directionally woven E-glass fabric/epoxy with different loading of graphite particles were made by hand layup followed by compression molding. Tensile and flexural behaviors, impact strength, hardness and density of these laminates were determined. Wear behaviors of these composites were investigated by a pin-on-disc wear test apparatus. Specific wear rates of these composites strongly depend on their filler content and applied normal loads. The hybrid composite containing 3 wt% of graphite exhibits the optimum mechanical and wear performances. A further increase in the graphite content increases the specific wear rate and deteriorates the mechanical behavior. The lowest (? e)-1 factor (the reciprocal of the product of tensile strength and elongation at break) signifies the lowest specific wear rate. The results of the morphology study of the wear test specimens support the results of the wear test. © 2012 Elsevier Ltd.
Mechanical properties and sliding wear behavior of jatropha seed cake waste/epoxy composites
(Springer Japan, 2015) Shivamurty, B.; Murthy, K.; Joseph, P.C.; Rishi, K.; Bhat, K.U.; Anandhan, S.
Jatropha seed cake particulate (JSCP)-reinforced epoxy composites were prepared by open mold resin casting method. The influence of JSCP on mechanical and dry sliding wear properties of epoxy was experimentally investigated as per the ASTM standards. Dry sliding wear test was conducted for these composites at a constant sliding distance of 500 m with different sliding velocities and applied loads by a pin-on-disc wear test machine. The results revealed that incorporation of JSCP decreased the specific wear rate and coefficient of friction while improving the mechanical properties. The composite reinforced with 40 wt% of JSCP exhibited better mechanical properties and wear behavior compared to the neat epoxy and other compositions of JSCP/epoxy composites. The results of this study indicate that jatropha seed cake powder can be used as biosolid lubricant filler for epoxy. © 2014, Springer Japan.
Sliding wear and mechanical properties of alumina/glass fabric/epoxy composites
(Huthig GmbH, 2015) Shivamurty, B.; Anandhan, S.; Bhat, K.U.
In this study, laminates of neat glass fabric/ epoxy composite (GEC) and three levels of Al2O3 filled glass fabric/epoxy composites, designated as 3AGEC, 6AGEC and 9AGEC (micro particulates of Al2O3 - by 3, 6 and 9 wt. % of resin respectively) were prepared using hand lay-up method. 3AGEC exhibits higher tensile strength, flexural strength and flexural modulus besides improved hardness compared to GEC, 6AGEC and 9AGEC. 3AGEC exhibits the lowest specific wear rate compared to GEC, 6AGEC and 9AGEC at all the three loads (i.e., 15, 30 and 45 N) and at a constant sliding velocity of 3.5 m· s-1 for a sliding distance of 1.5 km. It was found that beyond filler content of 3 wt. % is deteriorates the mechanical and sliding wear properties of the composites due to agglomeration of the filler. Also, it was found that lowest factor signifies lowest specific wear rate in both neat and all the Al2O3 filled composites.
Structure-property relationship of glass fabric/MWCNT/epoxy multi-layered laminates
(Elsevier Ltd, 2020) Shivamurty, B.; Anandhan, S.; Bhat, K.U.; Thimmappa, B.H.S.
Neat glass fabric/epoxy composites (GECs) and multi-wall carbon nanotube/glass fabric/epoxy composites (MWCNTGECs) were prepared by hand-lay-up followed by compression molding technique and investigated the structural properties. It is found that the mechanical properties and wear resistance of the glass fabric reinforced epoxy composite improved upon the addition of MWCNTs. The 0.3 wt%MWCNTs filled glass fabric/epoxy composite (0.3MWCNTGECs) exhibits better properties as compared to 0.075 wt% MWCNT filled glass fabric/epoxy composites (0.075MWCNTCs), 0.15 wt% MWCNT filled glass fabric/epoxy composites (0.15MWCNTCs) and GECs. The mechanism of wear failure of these composites was analyzed from the morphology of worn surfaces. It was observed solid lubricant film established on the wear track at higher normal loads reduces the wear. The correlation of Vickers's hardness and Lancaster factor (?e)?1 with specific wear rate is investigated and reported. © 2020
Synthesis and characterization of cu-doped ZnO nanofibers for ethanol vapor sensing
(Cogent OA, 2024) Prabhu, N.N.; Shivamurty, B.; Anandhan, S.; B V, R.; R B, J.C.
Pure and copper-doped zinc oxide (ZnO) nanofibers (NFs) were fabricated by the sol-gel electrospinning (ES) technique with varying concentrations (1, 3, and 5 w%). Scanning electron microscope (SEM), X-ray diffraction (XRD), and ultraviolet-visible (UV-Vis) spectroscopy were used to investigate the morphology, structure, and optical properties of the NFs. The average fiber diameter (AFD) of the Cu-doped ZnO (Cu-Z) NFs decreased with the increase in doping concentration. The structural analysis found that all the NFs samples were polycrystalline and oriented along the (101) plane. Also, the crystalline size decreased from 26.58 to 18.45 nm as the copper (Cu) concentration increased, and a maximum crystalline size was observed for 5 w% Cu-Z NFs. The band gap of undoped and Cu-Z NFs was calculated from UV VIS spectra, and it was observed that the bandgap decreased from 3.45 to 2.9 eV due to the addition of 5 w% Cu. The sensing performance of the NFs was investigated for 50 ppm of ethanol vapor at various operating temperatures (25–300 °C). The results indicated that the 5 w% Cu-Z NFs had the highest response to ethanol vapor, of 12.65 for 50 ppm, with response and recovery times of 70s and 35s. The Cu-Z NFs exhibited good selectivity and stability while tested with other vapors. © 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Thermal and Flammability Properties of Glass Fabric/MWCNT/Epoxy Multilayered Laminates
(Korean Institute of Electrical and Electronic Material Engineers, 2021) Shivamurty, B.; Anandhan, S.; Bhat, K.U.; Thimmappa, B.H.S.
Multiwalled Carbon Nano Tube (MWCNT) filled glass fabric reinforced epoxy composites (MWCNT/GEC), and neat GEC were prepared by hand-lay-up followed by hot compression molding method. As per the ASTM standard, specimens were prepared and investigated the influence of the addition of MWCNTs on flammability properties of GEC through the UL-94 vertical flammability test and the limiting oxygen index (LOI) method. The thermal degradation was studied by thermogravimetric analysis (TGA). It was found that the GEC improved upon the thermal stability and fire-retardant properties due to the addition of MWCNTs. It was observed that the 0.3 wt.% MWCNTs-glass fabric reinforced epoxy composite (0.3MWCNT/GEC) exhibits better properties than neat GEC and 0.075 wt.% MWCNT-glass fabric reinforced epoxy composite (0.075MWCNT/GEC) and 0.15 wt.% MWCNT-glass fabric reinforced epoxy composites (0.15MWCNT/GEC). Hence, this material may be suitable for electrical devices and appliances based on the other required properties’ further fulfillment. © 2021, The Korean Institute of Electrical and Electronic Material Engineers.
Tribology and Mechanical Properties of Carbon Fabric/MWCNT/Epoxy Composites
(Hindawi Limited 410 Park Avenue, 15th Floor, 287 pmb New York NY 10022, 2018) Shivamurty, B.; Murthy, K.; Anandhan, S.
Cryogenic treated multilayered carbon fabric/oxidized multiwall carbon nanotube/epoxy (CCF/O-MWCNT/E) composite and untreated carbon fabric/epoxy (CF/E) composite were prepared by hot compression molding technique. The density and mechanical properties such as tensile properties, flexural properties, interlaminar shear strength, and microhardness of the composites were investigated as per ASTM standards. The wear and coefficient of friction behavior were investigated using computer interfaced pin-on-disc test rig at room temperature for varied load and sliding speed. The morphology of worn surfaces of the wear test composite specimens were studied by scanning electron microscope. It is found that the synergetic effect of addition of O-MWCNT to epoxy matrix and cryogenic treatment of carbon fabric improved the wear resistance and mechanical properties. Also, a thin lubricating film developed by the oxidized multiwall carbon nanotube/epoxy wear debris reduces the coefficient of sliding friction and wear rate. © 2018 B. Shivamurthy et al.
Understanding the interplay of solution and process parameters on the physico-chemical properties of ZnO nanofibers synthesized by sol-gel electrospinning
(Institute of Physics, 2023) Prabhu, N.N.; Rajendra, B.V.; Anandhan, S.; Murthy, K.; Jagadeesh Chandra, R.B.; George, G.; Kumar, B.; Shivamurty, B.
Aging populations and the increase in chronic diseases worldwide demand efficient healthcare tools for simple, rapid, and accurate diagnosis and monitoring the human health. In this context, gas sensors are used to analyze the type of gas in the breath to diagnose chronic diseases. Metal oxide and ceramic nanofibers (NFs) produced by the electrospinning (ES) method have been investigated for potential use as gas sensors in the engineering and medical sectors. The material and process parameters are the main influencing factors on the functional performance of electrospun metal oxide NFs. Zinc oxide (ZnO) based NFs are used in various gas sensors due to the wide band gap (3.37eV), large exciton binding energy, and high mobility of charge carriers of ZnO. In this research, we made an attempt to study the effect of poly(vinyl alcohol) (PVA) and zinc acetate dihydrate (ZnAc2) concentrations and feed rate, voltage, spinneret tip-to-collector distance (TCD), and pyrolysis temperature on the physical properties of ZnO NFs. An average fiber diameter of 119 nm was obtained after pyrolysis at 600 °C of electrospun fiber produced from an aqueous PVA solution of concentration 15 w% with 7.5 w% ZnAc2 based on the weight of PVA. The grain size, transmittance, structural defects, and band gap energy of NFs were found to increase as a function of the pyrolysis temperature, which could be beneficial for the functional applications of these NFs. © 2023 The Author(s). Published by IOP Publishing Ltd