ABSTRACT
3D printers are increasingly used after the spread of the COVID-19 pandemic. This machine was used to overcome the lack of medical devices and personal protective equipment. In order for printed objects to be useful in the medical field, the mechanical properties of these objects must be known. The main objective of this study is to assess the mechanical properties of parts manufactured in polylactic acid by a 3D printer machine. The mechanical properties are determined from the experimental results of the three-point bending test. The results obtained show that the mechanical properties depend on the process parameters. The analysis of variance was used to determine the printing parameters that have a statistically significant effect on the mechanical properties. The optimal printing parameters are determined to manufacture parts with high mechanical performance and used them in complete safety. The finite element analysis was performed using ANSYS mechanical APDL software to validate the experimental results.
ABSTRACT
The 3D printing technology allows to overcome the lack of medical equipment during the Covid19 pandemic around the world. The PLA is widely used to produce medical devices and personal protective equipment. The aim of this paper is to determine the mechanical behavior of PLA-parts fabricated using Open-Source 3D printer based on FDM process. The mechanical behavior is characterized by two proprieties which are flexural strength and flexural modulus of elasticity. The mechanical properties are determined from the experimental results of three-point bending test according to the following process parameters: printing speed, deposition angle and extruder temperature. The results obtained show that the mechanical properties depend on the three process parameters. The response surface method and the variance analysis technique were used to establish an empirical model between process parameters and mechanical properties. The optimal printing parameters were determined using the desirability function. The Finite Element Analysis for Flexural Strength was performed to validate the experimental results. © 2020 IEEE.
ABSTRACT
Introduction: COVID-19 is an infectious disease caused by a new coronavirus. The first cases were identified in Wuhan. It rapidly spread causina pandemic worldwide. The incidence and severity of this disease are likely to be different in children compared with adults. Few publications COVID-19 in children have been published. Our Moroccan paediatric series is among the first studies on this disease in Africa.Methods: we included all children with COVID-19 who were admitted and treated at the hospital from March 25 to April 26, 2020. We have collected information, including demographic data, symptoms, imaging data, laboratory results, treatments and clinical progress from patients with COVID-19.Results: since the outbreak of 2019 novel coronavirus infection (2019-nCoV) in Morocco, a total of 145 COVID-19 confirmed cases have been reported in the Cheikh Khalifa’s Hospital. Among this cases, 15 children were registered. The median age of patients was 13 years. There were 7 boys and 8 girls. Five children are asymptomatic, 8 have mild symptoms and 2 have a moderate respiratory difficulty. The RT-PCR test results were positive in all patients. Radiologically, we found in 2 cases, multiple nodules with ground-glass opacities on the chest scan. The treatment was based on the combination of hydroxychloroquine and azithromycin. Evolution under treatment was good for all patients.Conclusion: this study describes the profile of COVID-19 in child in a Moroccan hospital and confirms that the severity of illness in children wCOVID-19 to be far less than adults.