Background: During the coronavirus disease 2019 (COVID-19) pandemic, temporary foreign workers (TFWs) provided a critical role to maintaining the food supply in Canada, yet workers faced a number of challenges that made them particularly vulnerable to COVID-19. The objective of this study was to describe the epidemiological investigation and public health response to a COVID-19 outbreak among TFWs in an agricultural setting in British Columbia from March to May 2020. Methods: An outbreak was declared on March 28, 2020 following detection of two cases of COVID-19 among a group of 63 TFWs employed by a nursery and garden centre. Outbreak control measures included immediate isolation of cases, case finding via outreach screening and testing, cohorting of asymptomatic workers and enhanced cleaning and disinfection. The outbreak was declared over on May 10, 2020. Results: A total of 26 COVID-19 cases were identified among the group of TFWs; no cases were identified among local workers. Cases were primarily male (77%) with a median age of 41 years. Symptom onsets ranged from March 8 to April 9, 2020. One case required overnight hospitalization for pneumonia. Conclusion: This was the first COVID-19 community outbreak identified in British Columbia and the first COVID-19 outbreak identified among TFWs in Canada. This outbreak began prior to implementation of provincial and federal quarantine orders for international travellers. A provincial policy was later developed that requires TFWs to quarantine in government-funded accommodation prior to deployment to agricultural settings.
International audienceThe gas turbine combustion chamber of aero-engines requires a thermal barrier coating (TBC) by thermal spraying. Further heat protection is achieved by laser drilling of cooling holes. The residual stresses play an important role in the mechanical behaviour of TBC. It could also affect the TBC response to delamination during laser drilling. In this work, studies of the cracking behaviour after laser drilling and residual stress distribution have been achieved for different bond coats by plasma spray or cold spray. From interface crack length measured pulse-by-pulse after laser percussion drilling at 20° angle, the role of the various bond coats on crack initiation and propagation are investigated. It is shown that the bond coat drastically influences the cracking behaviour. The residual stresses profiles were also determined by the incremental hole-drilling method involving speckle interferometry. An original method was also developed to measure the residual stress profiles around a pre-drilled zone with a laser beam at 90°. The results are discussed to highlight the influence of TBCs interfaces on the resulting residual stresses distribution before laser drilling, and also to investigate the modification around the hole after laser drilling. It is shown that laser drilling could affect the residual stress state
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