The design and development of high-strength and low-weight composite landing gear struts is still a challenge in today’s world. In this study, a selection methodology for fiber-reinforced composite material for retractable main landing gear struts for specified lightweight aircraft up to 1600 kg mass is proposed. Four different fiber-reinforced composite materials, two each from the glass-fiber and carbon-fiber families, including E-glass fiber/epoxy, S-glass fiber/epoxy, T300 carbon fiber/epoxy, and AS carbon fiber/epoxy, were considered for analysis. For the design and analysis of a main landing gear strut, maximum landing loads for one point and two point landing conditions were calculated using FAA FAR 23 airworthiness requirements. Materials were categorized based on their strength-to-weight ratio and the Tsai-Wu failure criterion. Landing gear struts meeting the Tsai-Wu failure criterion, and having a maximum strength-to-weight ratio, were then modeled for performance under a collision detection test. This research concludes that T300 carbon fibre/epoxy is a recommended material for the manufacture of landing gear struts for specified lightweight aircraft.

Background: The new severe acute respiratory syndrome coronavirus 2 is the cause of the transmissible sickness known as coronavirus disease 2019 (COVID-19) (SARS-CoV-2). Although it often presents as an acute respiratory infection, it can also have a negative impact on the kidneys, heart, gastrointestinal, and nervous system. The aims of this study to find out the association of renal biomarkers among dialysis patients in COVID-19 positive and negative. Methods: A retrospective study was conducted in the Department of medical laboratory technology, the university of Haripur, Khyber Pakhtunkhwa, Pakistan. A Total of 129 Dialysis patients blood samples were collected from March 2022 to April 2022 in which 13 males and 20 females are COVID-19 positive while 41 males and 55 females are COVID-19 negative. The obtained data was statistically analyzed by using PRISM version 5.0 by applying two-way ANOVA and Comparisons between Covid positive and negative patients RFTs by using Bonferroni posttest. Results: Male patients with chronic kidney disease (on dialysis) with COVID-19 negative and positive their mean urea difference was 95.20mg/dl and 159.6mg/dl, while COVID-19 negative and positive the mean creatinine difference was 8.534mg/dl and 13.81mg/dl respectively. While there was no significance difference in uric acid concentration in CKD patients with COVID-19 negative and positive. Female patients with chronic kidney disease (on dialysis) with COVID-19 negative and positive their mean urea difference was 103.20mg/dl and 152.6mg/dl, while COVID-19 negative and positive the mean creatinine difference was 8.114mg/dl and 8.584mg/dl respectively. While there was no significance difference in uric acid concentration in CKD patients with COVID-19 negative and positive. Conclusion: This study concludes that there is positive relationship or association of renal biomarkers in COVID-19 positive patients. Significance association between urea and creatinine in COVID-19 positive.