The effects of the design and optimization of trapezoidal channels and baffles on the net power density of proton-exchange membrane fuel cells (PEMFCs) are studied. The significant effects of the length of upper and lower sides of the trapezoidal cross section and the number and position of baffles on the net power density of PEMFC have been investigated. It is found that at the same flow rate, changing the effective contact surface between the flow channel and the gas diffusion layer can tremendously improve the current density of fuel cells; moreover, the performance of a PEMFC based on the addition of a baffle can be further improved. The results show that the trapezoidal cross-sectional flow channel with baffles has higher efficiency and better overall performance compared with a basic straight flow channel. In addition, the response surface was used to optimize the trapezoidal cross-sectional flow channel by considering the power loss of output power and the flow rate. The optimal result was obtained with an upper side length of 1.234 mm, a lower side length of 1.8 mm, and a baffle from the entrance at 9.5 mm, increasing the net power density by 4.347%.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8830067 | PMC |
http://dx.doi.org/10.1021/acsomega.1c05829 | DOI Listing |
iScience
January 2025
Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1, 8093 Zürich, Switzerland.
In 2022, the European Union put forward the REPowerEU plan in response to Russia's invasion of Ukraine, aiming at enhancing short-term energy security by diversifying imports and reducing natural gas demand while accelerating the deployment of renewable alternatives in the long term. Here, we quantify the life cycle environmental impacts of both REPowerEU's short-term measures, including the controversial extended coal-fired power plant operations, and how the first year of the crisis was managed in practice. We find that the policy measures' impact on greenhouse gas (GHG) emissions would be negligible, although they could have detrimental effects on other environmental categories.
View Article and Find Full Text PDFHeliyon
January 2025
Institute of Power Engineering, Riga Technical University, Azenes iela 12/1, Riga, LV, 1048, Latvia.
This paper addresses the participation of independent aggregators (IAs) for demand response (DR) in European electricity markets. An IA is an aggregator trading the flexibility of consumers of which it is not the electricity supplier. Particularly, we focus on the controversial issue of a compensation payment from the IA to the supplier for energy sourcing.
View Article and Find Full Text PDFClinics (Sao Paulo)
January 2025
Emergency Department, Kunshan Hospital Affiliated to Jiangsu University, Qianjin East Road, China. Electronic address:
Objectives: Mild Traumatic Brain Injury (mTBI) is quite prevalent in the elderly population, and the authors performed a retrospective analysis regarding the predictive value of frailty assessing tools regarding the prognosis of elderly mTBI patients.
Methods: All the patients underwent assessment of frailty upon admission using five tools including Frailty Phenotype (FP), FRAIL Scale (FS), Edmonton Frailty Scale (EFS), Groningen Frailty Indicator (GFI), and Clinical Frailty Scale (CFS). The predicting potential of tools was analyzed against the prognosis defined by the extended Glasgow Outcome Scale (GOSE).
Clin Med (Lond)
January 2025
Professor of Hepatology, School of Health Sciences, Faculty of Health and Medical Sciences, University of Surrey, Access and Medicine, Royal Surrey NHS FTInstitute of Liver Studies, Kings College Hospital NHS FT. Electronic address:
Aim: To evaluate an intervention (a film and electronic leaflet) disseminated via text message by general practices to promote COVID-19 preventative behaviours in Black and South Asian communities.
Methods: We carried out a before-and-after questionnaire study of attitudes to and implementation of COVID-19 preventative behaviours and qualitative interviews about the intervention with people registered with 26 general practices in England who identified as Black or South Asian.
Results: In the 108 people who completed both questionnaires, we found no significant change in attitudes to and implementation of COVID-19 preventative behaviours, although power was too low to detect significant effects.
Plants (Basel)
January 2025
Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
Alpine meadows are vital ecosystems on the Qinghai-Tibet Plateau, significantly contributing to water conservation and climate regulation. This study examines the energy flux patterns and their driving factors in the alpine meadows of the Qilian Mountains, focusing on how the meteorological variables of net radiation (), air temperature, vapor pressure deficit (), wind speed (), and soil water content () influence sensible heat flux () and latent heat flux (). Using the Bowen ratio energy balance method, we monitored energy changes during the growing and non-growing seasons from 2022 to 2023.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!