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2019 - 201912020 - 20231
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Author: Raman Devi × Start date: 2018 × Type: Thesis ×
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    ThesisItemOpen Access
    Sustainable energy storage in supercapacitors using agro-waste materials
    (CCSHAU, Hisar, 2023-05) Raman Devi; Vinay Kumar
    Eco-friendly and low-cost agro-waste derived novel materials have been fascinated a lot of attention to generating porous activated carbon (AC), graphene oxide (GO), biochar, etc, with specific surface parameters (surface area, pore size, pore volume) required for energy storage applications. In this work, paddy straw and sugarcane bagasse, the agro-waste, are utilized to synthesize AC and GO. As-produced ACP-5M acquired a high SSA of 1358 m2 g-1 with hierarchical pore configuration. In order to enhance the electrochemical performance of ACP and GO were composited with manganese oxide to increase the active sites. The prepared materials were characterized using different characterization tools like XRD, FTIR, FR-SEM, BET, XPS and TEM. The electrochemical was tested using CV, GCD and EIS techniques. The composite of MnO2 with ACP-5M obtained the specific capacitance of 438 F g-1 in 6 M KOH aqueous electrolyte with a specific energy of 60.8 Wh kg-1 at a specific power of 500 W kg-1. In addition, the symmetric device fabricated using this material offers a specific capacitance of 239 F g-1 with a specific energy of 65.06 Wh kg-1 at a specific power of 699.2 W kg-1. Hence, these findings suggest that all the synthesized electrode materials can be applied as efficient and effective electrode materials in high-performance supercapacitors.
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    ThesisItemOpen Access
    Study on temperature dependent dielectric properties of honey for quality assessment
    (CCSHAU, 2019) Raman Devi; Paul Singh
    Honey, being valuable nutrient product of high price and in short supply, has become a prime target for economically motivated adulteration. This may involve illegal adulteration by adding water or sugar syrups as well as overheating. Therefore, inexpensive, fast, non-destructive methods for its quality assessment are of interest for food industry and consumers alike. For this purpose, dielectric assessment kit (DAK) which offer high precision dielectric parameter measurements such as permittivity, conductivity, loss tangent over a broad frequency range 4MHz to 67GHz was used. Affect of temperature and water content on dielectric properties of different brands A, B, C & D of honey was investigated with an open-ended coaxial line probe from 600 to 6000MHz at 25-55 ºC.The dielectric constant of honey is found to decrease with increase in frequency at a given value of temperature. The increase in temperature from 25 ºC to 55 ºC at an interval of 10 ºC resulted in an increase in both the dielectric constant and electrical conductivity over the whole range of frequency. The dielectric parameters for different brands A, B, C & D, when compared, it was found that dielectric constant and dielectric conductivity of brand C is consistent with the pure honey sample A whereas the parameters for C and D are significantly different from A. Hence, there is adulteration of water in the honey sample B and D. The dielectric loss factor in all the brands is found significantly different from each other and finally, the overheating and water content in honey strongly influence its dielectric parameters and their measurements can be utilized for quality assessment.