UVC-Based Air Disinfection Systems for Rapid Inactivation of SARS-CoV-2 Present in the Air.

The World Health Organization (WHO) declared in May 2021 that SARS-CoV-2 is transmitted not only by close contact with infectious respiratory fluids from infected people or contaminated materials but also indirectly through air. Airborne transmission has serious implications for the control measures we can deploy, given the emergence of more transmissible variants. This emphasizes the need to deploy a mechanism to reduce the viral load in the air, especially in closed and crowded places such as hospitals, public transport buses, etc. In this study, we explored ultraviolet C (UVC) radiation for its ability to inactivate the SARS-CoV-2 particles present in aerosols and designed an air disinfection system to eliminate infectious viruses. We studied the virus inactivation kinetics to identify the UVC dosage required to achieve maximum virus inactivation. Based on the experimental data, UVC-based devices were designed for the sanitization of air through HVAC systems in closed spaces. Further, a risk assessment model to estimate the risk reduction was applied which showed that the use of UVC radiation could result in the reduction of the risk of infection in occupied spaces by up to 90%.

Experimental Study to Evaluate the Wear Performance of UHMWPE and XLPE Material for Orthopedics Application.

The main objective of this study is to perform an abrasive wear resistance study of UMHWPE and XLPE by using different grades of abrasive paper (grade 100 (190 µm), grade 220 (50 µm), and grade 400 (40 µm)) with minor (10 N) and major (15 N) loading conditions. In this article, wear performance of the UMHWPE and XLPE materials compared to the bio-tribological data as reported earlier in the clinical studies has been investigated. The experimental result shows that the loss of materials for the XLPE was much higher than the UHMWPE under similar loading conditions. UHMWPE shows a 34% reduction in wear at minor loading conditions and a 53% reduction in wear at major loading conditions. From experimental results it was concluded that Cross-link PE has better wear resistance than UHMWPE in minor wear conditions, whereas UHMWPE shows better wear resistance under major loading conditions. Based upon these results, UHMWPE and XLPE have been recommended for use as bearing materials in orthopedics. The experimental results of this study were validated using results from the available literature.

Performance Evaluation of Different Coating Materials in Delamination for Micro-Milling Applications on High-Speed Steel Substrate.

The objective of the present work is to carry out analytical and finite element analysis for commonly used coating materials for micro-milling applications on high-speed steel substrate and evaluate the effects of different parameters. Four different coating materials were selected for micro-milling applications: titanium nitride (TiN), diamond-like carbon (DLC), aluminium titanium nitride (AlTiN) and titanium silicon nitride (TiSiN). A 3D finite element model of coating and substrate assembly was developed in Abaqus to find the Hertzian normal stress when subjected to normal load of 4 N, applied with the help of a rigid ball. The radius of the rigid ball was 200 µm. For all the coating materials, the length was 3 mm, the width was 1 mm, and the thickness was 3 µm. For the high-speed steel substrate, the length was 3 mm, the width was 1 mm, and the thickness was 50 µm. Along the length and width, coating and substrate both were divided into 26 equal parts. The deformation behaviour of all the coating materials was considered as linear-elastic and that of the substrate was characterized as elastic-plastic. The maximum normal stress developed in the FEA model was 12,109 MPa. The variation of the FEA result from the analytical result (i.e., 12,435.97 MPa is 2.63%) which is acceptable. This confirms that the FEA model of coating-substrate assembly is acceptable. The results shows that the TiSiN coating shows least plastic equivalent strain in the substrate, which serves the purpose of protecting the substrate from plastic deformation and the TiSiN of 3 micron thickness is the most optimum coating thickness for micro-milling applications.

Experimental and RSM-Based Process-Parameters Optimisation for Turning Operation of EN36B Steel.

The main objective of this article is to perform the turning operation on an EN36B steel work-billet with a tungsten carbide tool, to study the optimal cutting parameters and carry out an analysis of flank-wear. Experimental and simulation-based research methodology was opted in this study. Experimental results were obtained from the lab setup, and optimisation of parameters was performed using RSM (response surface methodology). Using RSM, cutting-tool flank-wear was optimised, and the cutting parameters which affect the flank wear were determined. In results main effect plot, contour plot, the surface plot for flank-wear and forces (Fx, Fy and Fz) were successfully obtained. It was concluded that tool flank-wear is affected by depth of cut, and that flank-wear generally increases linearly with increasing cutting-speed, depth of cut and feed-rate. To validate the obtained results, predicated and measured values were plotted and were in very close agreement, having an accuracy level of 96.33% to 98.92%.

Indoor air quality improvement in COVID-19 pandemic: Review.

INTRODUCTION: The advent of COVID-19 has impinged millions of people. The increased concern of the virus spread in confined spaces due to meteorological factors has sequentially fostered the need to improve indoor air quality. OBJECTIVE: This paper aims to review control measures and preventive sustainable solutions for the future that can deliberately help in bringing down the impact of declined air quality and prevent future biological attacks from affecting the occupant's health. METHODOLOGY: Anontology chart is constructed based on the set objectives and review of all the possible measures to improve the indoor air quality taking into account the affecting parameters has been done. OBSERVATIONS: An integrated approach considering non-pharmaceutical and engineering control measures together for a healthy indoor environment should be contemplated rather than discretizing the available solutions. Maintaining social distance by reducing occupant density and implementing a modified ventilation system with advance filters for decontamination of viral load can help in sustaining healthy indoor air quality. CONCLUSION: The review paper in the main, provides a brief overview of all the improvement techniques bearing in mind thermal comfort and safety of occupants and looks for a common ground for all the technologies based on literature survey and offers recommendation for a sustainable future.