This study applies a life cycle assessment (LCA) to the shared dockless standing e-scooter system that is established in Brussels. The results are given for four impact categories: global warming potential (GWP), particulate matter formation, mineral resource, and fossil resource scarcity. Regarding GWP, the use of the shared e-scooters in the current system causes 131 g of CO2-eq. per passenger-kilometer while the mode of transportation displaced has an impact of 110 g of CO2-eq. Thus, at present, the use of e-scooters shows a higher impact than the transportation modes they replace. The high results for the shared e-scooter, in terms of GWP, are mainly caused by the short lifespan of the shared e-scooter. Nevertheless, as the market further matures, the lifespan of e-scooters could increase and the impact per kilometer travelled could decrease accordingly. Regarding the use of the personal e-scooter, the LCA results show an impact of around 67 g of CO2-eq. This study quantifies the LC impacts of the current situation based on local, ‘real-life’ data. However, potential changes on soft mobility patterns induced by the use-oriented product-service system (PSS), such as a shared e-scooter system, could not be quantified.
1 February 2011 in Surface and Coatings Technology
Breathing control exercises are an important component of occupational therapy in patients with chronic obstructive pulmonary disease (COPD). Delivering these exercises in group settings may enhance their benefits. Therefore, this study assessed the effectiveness of breathing control exercises delivered in a group format to patients with severe COPD remitting from an acute pulmonary exacerbation. This randomized controlled trial of 6 weeks’ duration compared the addition of breathing exercise sessions delivered in a group setting to a standard exercise inpatient rehabilitation program (usual care) versus usual care alone. The standard exercise program consisted of endurance and strength training and therapeutic patient education. The intervention group received, in addition to usual care, 20 sessions of 30 min duration of breathing control exercises in a group setting. The primary outcome was quality of life (Saint George’s Respiratory Questionnaire). Secondary outcomes were the COPD assessment test, modified Borg scale, handgrip strength test, and five-time sit-to-stand test. Thirty-seven patients aged 69 ± 7 years were recruited. After the 6-week period, all outcomes significantly improved and exceeded the minimal clinically important difference in the intervention group only. Between-group changes were significant for each outcome. Conclusions: breathing control exercises in a group setting provide clinically relevant benefits in patients with severe COPD who are remitting from an acute pulmonary exacerbation.
A strategy is proposed to cope with combined thermal fatigue and hot corrosion resistance affecting industrial coatings. It allows comparing different materials, coatings and geometries with respect to thermal cracking and then properly selecting protective coatings. It uses a thermo-mechanical model combining the heat transfer conditions, thermal and mechanical properties of the materials and the system geometry. The model is applied to two cases: (i) borided steel, with experimental support; (ii) multilayer coating made of a thermal barrier layer, aimed at reducing thermal gradients in the system, and a corrosion layer.
Wear mitigation in a sliding couple is challenging if wear has to be minimized on both surfaces. In this paper, ball-on-disk testing is performed on sliding couples where both surfaces (ball and disk) are treated for wear resistance. Studied materials are pack borided H13 tool steel (ASTM A681), pack borided AISI 420 stainless steel (ASTM A276) and plasma sprayed yttria-stabilized zirconia (YSZ). Borided H13 steel exhibits a single phase Fe2B layer, while AISI 420 has a double phase layer, with FeB on the outer surface. Both FeB/Fe2B and FeB/YSZ couples generate three-body abrasion. In the latter case, mass transfer occurs from the ball to the disk as well. Friction coefficient is ~0.6 for the AISI 420/Fe2B and FeB/Fe2B sliding pairs, with less vibration on the latter and wear rates close to 10−3 mm³·(N·m)−1 for both the ball and the disk. In comparison, the FeB/YSZ pair has a friction coefficient of ~0.65, a similar total mass loss, but a much higher wear rate for YSZ than for FeB.