ABSTRACT
One of the most promising and widely used additive manufacturing technologies, fused deposition modelling (FDM), is based on material extrusion and is most commonly used for producing thermoplastic parts for functional applications with the objectives of low cost, minimal waste and ease of material conversion. Considering that pure thermoplastic materials have a significantly poor mechanical performance, it is necessary to enhance the mechanical properties of thermoplastic parts generated using FDM technology. One of the conceivable techniques is to incorporate reinforcing materials such as short glass fibre (SGF) into the thermoplastic matrix in order to produce a polymer composite that can be used in engineering applications, such as structural applications. The morphological and mechanical properties of SGF (short glass fibre) reinforced ABS- (Acrylonitrile Butadiene Styrene) based polymer composites created via the method of FDM (fused deposition modelling) were investigated in this work. Properties were evaluated at three different weight percentages (0, 15 and 30 wt%). The composite filaments were developed using the process of twin screw extrusion. The comparison was made between ABS + SGF (short glass fibre) composites and pure ABS of mechanical properties that include surface roughness, tensile strength and low-velocity impact. The tests were carried out to analyze the properties as per ASTM standards. It has been found that the impact strength and tensile strength show an improvement in glass fibre inclusion; moreover, alongside the direction of build, the surface roughness had been reduced. The studies also focused on studying the dispersion characters of SGF in ABS matrix and its impact on the properties. Strength and modulus of SGF reinforced ABS composite has been significantly improved along with reduction of ductility. A 57% increase in tensile strength has been noted for 30 wt% addition of SGF to ABS in comparison to pure ABS. It was also interesting to note the reduction in surface roughness with every incremental addition of SGF to ABS. A 40% reduction in surface roughness has been observed with a 30 wt% addition of SGF to ABS in comparison to pure ABS.
ABSTRACT
BACKGROUND: The COVID-19 pandemic has brought to light the lacunae in the preparedness of healthcare systems across the globe. This preparedness also includes the safety of healthcare providers (HCPs) at various levels. Sudden spread of COVID-19 infection has created threatening and vulnerable conditions for the HCPs. The current pandemic situation has not only affected physical health of HCPs but also their mental health. OBJECTIVE: This study aims to understand the prevalence and severity of secondary traumatic stress, optimism parameters, along with states of mood experienced by the HCPs, viz., doctors, nurses and allied healthcare professionals (including Physiotherapist, Lab technicians, Phlebotomist, dieticians, administrative staff and clinical pharmacist), during the COVID-19 lockdown in India. METHODOLOGY: The assessment of level of secondary traumatic stress (STS), optimism/pessimism (via Life Orientation Test-Revised) and current mood states experienced by Indian HCPs in the present COVID-19 pandemic situation was done using a primary data of 2,008 HCPs from India during the first lockdown during April-May 2020. Data was collected through snow-ball sampling technique, reaching out to various medical health care professionals through social media platforms. RESULT: Amongst the study sample 88.2% of doctors, 79.2 of nurses and 58.6% of allied HCPs were found to have STS in varying severity. There was a female preponderance in the category of Severe STS. Higher optimism on the LOTR scale was observed among doctors at 39.3% followed by nurses at 26.7% and allied health care professionals 22.8%. The mood visual analogue scale which measures the "mood" during the survey indicated moderate mood states without any gender bias in the study sample. CONCLUSION: The current investigation sheds light on the magnitude of the STSS experienced by the HCPs in the Indian Subcontinent during the pandemic. This hitherto undiagnosed and unaddressed issue, calls for a dire need of creating better and accessible mental health programmes and facilities for the health care providers in India.
