Aeroacoustic design and optimisation of an all-electric ducted fan propulsion module for low-noise impact

Abstract

Objective. To explore how lifestyle and demographic, socioeconomic, and disease-related factors are associated with supervised exercise adherence in an osteoarthritis (OA) management program and the ability of these factors to explain exercise adherence.Methods. A cohort register-based study on participants from the Swedish Osteoarthritis Registry who attended the exercise part of a nationwide Swedish OA management program. We ran a multinomial logistic regression to determine the association of exercise adherence with the abovementioned factors. We calculated their ability to explain exercise adherence with the McFadden R 2 .Results. Our sample comprises 19,750 participants (73% female, mean ± SD age 67 ± 8.9 years). Among them, 5,862 (30%) reached a low level of adherence, 3,947 (20%) a medium level, and 9,941 (50%) a high level. After a listwise deletion, the analysis was run on 16,685 participants (85%), with low levels of adherence as the reference category. Some factors were positively associated with high levels of adherence, such as older age (relative risk ratio [RRR] 1.01 [95% confidence interval (95% CI) 1.01-1.02] per year), and the arthritis-specific self-efficacy (RRR 1.04 [95% CI 1.02-1.07] per 10-point increase). Others were negatively associated with high levels of adherence, such as female sex (RRR 0.82 [95% CI 0.75-0.89]), having a medium (RRR 0.89 [95% CI 0.81-0.98] or a high level of education ). Nevertheless, the investigating factors could explain 1% of the variability in exercise adherence (R 2 = 0.012).Conclusion. Despite the associations reported above, the poorly explained variability suggests that strategies based on lifestyle and demographic, socioeconomic, and disease-related factors are unlikely to improve exercise adherence significantly.

An Affordable Acoustic Measurement Campaign for Early Prototyping Applied to Electric Ducted Fan Units

“…Concerning this need for structured experimental assessment of preliminary design at low cost, this case study on the electric ducted fan unit provides valuable insights for conducting such evaluation with relatively few resources and within a stringent timeframe. In contrast to well-tailored and detailed experimental studies concerning electric ducted fan noise [18,19] of the past hosted inside expensive facilities, the study concentrates on the overall aspects and an easy-to-realize and affordable method also during the starting phase of a new idea with a limited budget. In [18], the aeroacoustic aspects of the design, construction, and testing of an all-electric ducted fan propulsion unit inside a large anechoic test chamber are presented.…”

“…In contrast to well-tailored and detailed experimental studies concerning electric ducted fan noise [18,19] of the past hosted inside expensive facilities, the study concentrates on the overall aspects and an easy-to-realize and affordable method also during the starting phase of a new idea with a limited budget. In [18], the aeroacoustic aspects of the design, construction, and testing of an all-electric ducted fan propulsion unit inside a large anechoic test chamber are presented. In general, ducted fan configurations potentially reduce noise emissions significantly [19][20][21].…”

An Affordable Acoustic Measurement Campaign for Early Prototyping Applied to Electric Ducted Fan Units

“…Concerning this need for the structured experimental assessment of preliminary design at low cost, this case study on the electric ducted fan unit provides valuable insights for conducting such an evaluation with relatively few resources and within a stringent timeframe. In contrast to well-tailored and detailed experimental studies concerning the electric ducted fan noise [18,19] of the past hosted inside expensive facilities, the study concentrates on the overall aspects and an easy-to-realize and affordable method also during the starting phase of a new idea with a limited budget. In [18], the aeroacoustic aspects of the design, construction, and testing of an all-electric ducted fan propulsion unit inside a large anechoic test chamber are presented.…”

“…In contrast to well-tailored and detailed experimental studies concerning the electric ducted fan noise [18,19] of the past hosted inside expensive facilities, the study concentrates on the overall aspects and an easy-to-realize and affordable method also during the starting phase of a new idea with a limited budget. In [18], the aeroacoustic aspects of the design, construction, and testing of an all-electric ducted fan propulsion unit inside a large anechoic test chamber are presented. In general, ducted fan configurations potentially significantly reduce noise emissions [19][20][21].…”