Browsing by Author "Bhandari, S.S."
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ThesisItem Open Access Colorization of grayscale image using quaternion algebra(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2016-08) Bhandari, S.S.; Negi, Chetan SinghColorization of grayscale images is a long standing and ill-posed problem. There are many possible applications for colorization. The most obvious application is the colorization of monochrome images from archives. Studies have also gone into using colorization to highlight biomedical images in order to allow potential areas of interest to be easily visible. This seems to be a really good use of the technique in the medical industry and shows that there are many potential uses for colorization in other fields. Colorization can also be used to highlight potentially dangerous substances shown in grayscale x-rays at airport security. In this thesis work we discuss different methods of colorization, explore quaternion algebra and its application in image processing. The main aim of our proposed work is to investigate the various application of quaternion algebra in image processing and color grayscale images using quaternion algebra. Our proposed method is based on approach using seed color to initiate colorization process. We present a colorization method which uses operation of quaternion algebra to produce color image for a given input grayscale image. It is important to remember that the results of colorization are purely perceptual, even if the colors are wrong they may still be acceptable.ThesisItem Open Access Numerical investigations on phase change materials in a horizontal shell and tube thermal energy storage system using different fin configuration(G. B. Pant University of Agriculture and Technology, Pantnagar, 2022-09) Mallik, Shubham; Mallik, Shubham; Mallik, Shubham; Bhandari, S.S.; Bhandari, S.S.; Bhandari, S.S.In order to improve the melting performance of phase change materials (PCM) in latent heat thermal energy storage unit (LHTES), the Angled rectangular with U-shaped tip fin design is proposed in this work. A two-dimensional numerical model based on enthalpy porosity method and Boussinesq approximation were used to model PCMs phase change transformation and the Buoyancy effect. The melting behavior of PCM is investigated by melt front evolution, temperature variation, effect of natural convection and variation of Stefan and Fourier number respectively. The results conclude that Angled rectangular U-shaped tip fin LHTES design is best suitable to enhances melting performance of PCM. The melting time decreases by 80.60 %, 74.42 % and 79.69 % as compared to Bare pipe for Angled rectangular with U-shped tip fin for PCMs Lauric acid, Paraffin wax and Capric acid respectively. The solidification time also decreases by a factor these PCMs. The melting time also decrease by a factor of 71.13 % due to rotation effect of whole domain for Angled rectangular with U-shaped tip fin latent heat thermal energy storage system.ThesisItem Open Access Performance studies on hybrid solar cooker using phase change materials with internet of things based monitoring interface(G.B. Pant University of Agriculture and Technology, Pantnagar, District Udham Singh Nagar, Uttarakhand. PIN - 263145, 2022-03) Kukreti, Pratyush; Bhandari, S.S.The intermittent nature of solar energy is the major hindrance towards the large scale use of solar cookers. The possibility of cooking during off-sunshine hours can be explored by incorporating an energy storage unit to the solar cooker like a thermal energy storage material or thermal heating of absorber plate of solar cooker by photo-voltaic (PV) technology. In the present study, performance studies on hybrid solar cooker using phase change materials and PV technology have been performed to access the feasibility of solar cooker during off-sunshine hours. The hybrid solar cooker is also upgraded with internet of things (IoTs) based monitoring interface to enhance the user experience. The thermal performances of solar cookers are also evaluated according to the bureau of Indian standard (BIS). First and Second figure of merit results satisfy BIS limits. The performance comparison of solar cooker using different phase change materials during sunshine and offsunshine hours is the main focus of the present experimental study. Three different phase change materials Magnesium nitrate hexa-hydrate, Naphthalene and Acetanilide are selected. The effect of finned cooking vessel on boiling time is also studied. It is found form the experiments that finned cooking vessel increases thermal efficiency and reduces boiling time as compared to conventional un-finned vessel. Thermal performance of hybrid solar cooker is evaluated by calculating the thermal efficiency of PV heating system. In hybrid PV heating system, Acetanilide shows highest average thermal efficiency. Naphthalene showed best thermal behavior for storing latent thermal energy during sunshine hours and retrieve back its conserved energy to thermic fluid water during offsunshine hours. The thermal Performance of PCM in a solar cooker during low solar insolation is also studied. The results shows that evening cooking during winter season is possible provided the PCM is charged once.