Engineering Headway Vol. 26

Abstract: Vapour compression refrigeration system (VCRS) is being used in various applications, but their high power consumption poses challenges when it comes to energy efficiency and impact on the environment. One approach to improve performance of VCRS is through sub-cooling, which involves cooling the refrigerant coming out of the condenser coil. Dedicated mechanical sub-cooling system, which utilize a separate sub-cooling cycle attached to the main cycle, have shown the potential for enhancing system performance. This paper focuses on the study of the effect of alternative refrigerants, evaporator temperature, condenser temperature, degree of overlap, and the degree of sub-cooling on VCRS with dedicated mechanical sub-cooling system. The findings suggest that using R134a in both cycles leads to maximum COP of system and second-law efficiency. Optimizing certain variables such as evaporator temperature, condenser temperature, degree of overlap, and degree of sub-cooling can also enhance net COP and second-law efficiency of system. This paper investigates the optimum degree of sub-cooling under ideal dedicated mechanical sub-cooling cycles, and it is observed that the system have maximum net COP when degree of sub-cooling is 17 °C. Keywords: VCRS, Dedicated mechanical sub-cooling, COP, R134a, Energy analysis

Abstract: The heat transfer performance of a fin tube heat exchanger is played very important role for getting maximum performance. For obtain the maximum heat transfer performance used a lot of active and passive techniques by the researchers. In this paper the heat transfer performanceenhanced by using the modified delta winglet vortex generator.The rectangular plate dimensions are considered 300mm*200mm*4mm, in which 12 Thermo couples are fitted for measuring the effect of temperature and pressure difference. The colburn factor is further determined in relation to the Reynolds number with the aid of mathematical computations. As is well known, the performance of heat transfer is directly correlated with the colburn factor. The experimental procedure repeats two times, first without a winglet and the second time it is performed with a winglet. A comparison of heat transfer performance is to be done with or without the winglet.

Abstract: There is a growing demand in the dental implant sector which aims to recreate the exact function and appearance of natural teeth, including strength, textures, and seamless blending with nearby teeth. Therefore, choosing the best crown material is a vital and challenging decision. To address this challenge, current study employs a comprehensive approach using Finite Element Analysis (FEA) on a 3-D CAD model. The stress analysis was carried out on three different crown materials - commercially pure Titanium (cp Ti), Zirconia (ZR), and Lithium Disilicate (LD) and compared their performance with that of human tooth material. The computational analysis results reveal that the pure Titanium (cp Ti) crown has shown the least deformation while the LD crown has showed the highest deformation under same loading conditions. When maximum stress is compared, Titanium showed the highest value, followed by Zirconia, whereas Lithium Disilicate (LD) demonstrated stress and deformation levels comparable to those of natural teeth.

Abstract: Physical health illness has become the topic of discussion in every home but the issue of mental health illness is not given that much importance. Therefore, the present research aims to discuss the mental health illness caused due to the pandemic taking into account the hospitality/service industry of India. This research has coined five major themes by performing Qualitative Data Analysis (QDA) using NVIVO 12 software based on which a conceptual model is proposed. The model discusses the challenges and the solutions to deal with the twin problem of COVID-19 and mental health to alleviate the pain of people. The present research can become the basis for providing recommendations to governmental policy-makers, managers and society as a whole to support people in distress and to ensure that care is provided to people suffering from mental illness because failure in considering mental wellbeing seriously would lead to long term social and economic costs to the society.