scholarly journals Fully-developed laminar flow in trapezoidal ducts with rounded corners: a numerical solution and case study

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohammed S. Ismail ◽  
Mohamed R. Berber ◽  
Ziyad A. Alrowaili ◽  
Mohamed Pourkashanian
Keyword(s):  
Fuel Cells ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Accurate Estimation ◽  
Hydrogen Fuel Cells ◽  
Hydrogen Fuel ◽  
Content Type ◽  
Wide Range ◽  
Poiseuille Number ◽  
The Impact

Purpose This paper aims to numerically solve fully developed laminar flow in trapezoidal ducts with rounded corners which result following forming processes. Design/methodology/approach A two-dimensional model for a trapezoidal duct with rounded corners is developed and conservation of momentum equation is solved. The flow is assumed to be steady, fully developed, laminar, isothermal and incompressible. The key flow characteristics including the Poiseuille number and the incremental pressure drop have been computed and tabulated for a wide range of: sidewall angle (θ); the ratio of the height of the duct to its smaller base (α); and the ratio of the fillet radius of the duct to its smaller base (β). Findings The results show that Poiseuille number decreases, and all the other dimensionless numbers increase with increasing the radii of the fillets of the duct; these effects were found to amplify with decreasing duct heights or increasing sidewall angles. The maximum axial velocity was shown to increase with increasing the radii of the fillets of the duct. For normally used ducts in hydrogen fuel cells, the impact of rounded corners cannot be overlooked for very low channel heights or very high sidewall angles. Practical implications The data generated in this study are highly valuable for engineers interested in estimating pressure drops in rounded trapezoidal ducts; these ducts have been increasingly used in hydrogen fuel cells where flow channels are stamped on thin metallic sheets. Originality/value Fully developed laminar flow in trapezoidal ducts with four rounded corners has been solved for the first time, allowing for more accurate estimation of pressure drop.

scholarly journals Comparative Life Cycle Assessment of Propulsion Systems for Heavy-Duty Transport Applications

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3079
Author(s):  
Sam Simons ◽  
Ulugbek Azimov
Keyword(s):  
Fuel Cells ◽  
Internal Combustion Engines ◽  
Hydrogen Fuel Cells ◽  
Hydrogen Fuel ◽  
Heavy Duty ◽  
Area Of Interest ◽  
Transportation Emissions ◽  
Reduce Emissions ◽  
The Uk ◽  
The Impact

To meet climate change challenges, the UK government is aiming to reach zero emissions by 2050. The heavy-duty transportation sector contributes 17% to the UKs total emissions, so to combat this, alternative power units to traditional fossil fuel-reliant internal combustion engines (ICEs) are being utilized and investigated. Hydrogen fuel cells are a key area of interest to try and reduce these transportation emissions. To gain a true view of the impact that hydrogen fuel cells can have, this study looks at the impact the manufacturing of a fuel cell has upon the environment, from material extraction through to the usage phase. This was done through the use of a lifecycle assessment following ISO 14040 standards, with hydrogen systems being compared to alternative systems. This study has found that whilst fuel cells depend upon energy intensive materials for their construction, it is possible to reduce emissions by 34–87% compared to ICE systems, depending upon the source of hydrogen used. This study shows that hydrogen fuel cells are a viable option for heavy-duty transport that can be utilized to meet the target emissions reduction level by 2050.

scholarly journals Forecasting the Hydrogen Demand in China: A System Dynamics Approach

Mathematics ◽  
2022 ◽  
Vol 10 (2) ◽  
pp. 205
Author(s):  
Jingsi Huang ◽  
Wei Li ◽  
Xiangyu Wu
Keyword(s):  
Fuel Cells ◽  
System Dynamics ◽  
Petroleum Refining ◽  
Refining Industry ◽  
Published Data ◽  
Hydrogen Fuel Cells ◽  
Hydrogen Fuel ◽  
Policy Makers ◽  
The Impact ◽  
Vehicle Market

Many countries, including China, have implemented supporting policies to promote the commercialized application of green hydrogen and hydrogen fuel cells. In this study, a system dynamics (SD) model is proposed to study the evolution of hydrogen demand in China from the petroleum refining industry, the synthetic ammonia industry, and the vehicle market. In the model, the impact from the macro-environment, hydrogen fuel supply, and construction of hydrogen facilities is considered to combine in incentives for supporting policies. To further formulate the competitive relationship in the vehicle market, the Lotka–Volterra (LV) approach is adopted. The model is verified using published data from 2003 to 2017. The model is also used to forecast China’s hydrogen demand up to the year of 2030 under three different scenarios. Finally, some forward-looking guidance is provided to policy makers according to the forecasting results.

Portable power source based on air-hydrogen fuel cells with free-breathing cathodes

2011 ◽  
Vol 37 (5) ◽  
pp. 412-416
Author(s):  
S. A. Gurevich ◽  
E. I. Terukov ◽  
O. I. Kon’kov ◽  
A. A. Tomasov ◽  
N. K. Zelenina ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Free Breathing ◽  
Power Source ◽  
Hydrogen Fuel Cells ◽  
Hydrogen Fuel ◽  
Portable Power

scholarly journals Evaluating undergraduate research conferences as vehicles for novice researcher development

2016 ◽  
Vol 7 (2) ◽  
pp. 159-177 ◽  
Author(s):  
Pauline Kneale ◽  
Andrew Edwards-Jones ◽  
Helen Walkington ◽  
Jennifer Hill
Keyword(s):  
Undergraduate Students ◽  
Undergraduate Research ◽  
Skills Development ◽  
Learning Context ◽  
Content Type ◽  
Research Conference ◽  
Researcher Development ◽  
Development Framework ◽  
Wide Range ◽  
The Impact

Purpose This paper aims to focus on the undergraduate research conference as its sphere of study and investigate the impact of significance of participation and socialisation in such activities on student attitudes and professional development. Using situated learning to theoretically position the undergraduate research conference as an authentic learning context, connection is also made with the concept of graduate attributes. Design/methodology/approach The Vitae (2014) Researcher Development Framework (RDF) is used to provide a template for charting the experiences and development of undergraduate students as researchers. This can be applied to short-term activities and programmes and to long-term career plans. The insights from 90 undergraduate students participating in three national undergraduate research conferences were obtained through interviews, and thematically analysed to map the students’ skills development against the RDF criteria. Findings Three main aspects of undergraduate research conference participation were considered particularly important by the students: the value of paper presentations, the value of poster presentations and the value of the overall conference experience. Within these themes, participants identified a wide range of skills and attributes they felt they had developed as a result of either preparing for or participating in the conferences. The majority of these skills and attributes could be mapped against the different domains of the RDF, using a public engagement lens for comparing actual with expected developmental areas. Research limitations/implications This research helps undergraduate research conference organisers construct programme content and form it in such a way that students’ skill development can be maximised prior to, and during, the course of an event. Learning developers can also use these findings to help understand the support needs of students preparing to deliver papers at such conferences. So far, little empirical research has examined students’ skills development within the undergraduate research conference arena. Originality/value The outcomes of this study show the diversity of the skills that students developed and the value of the conference format for offering networking practice and enhancing the communication skills which employers value.

scholarly journals In VivoEfficacy of Anuran Trypsin Inhibitory Peptides against Staphylococcal Skin Infection and the Impact of Peptide Cyclization

2015 ◽  
Vol 59 (4) ◽  
pp. 2113-2121 ◽  
Author(s):  
U. Malik ◽  
O. N. Silva ◽  
I. C. M. Fensterseifer ◽  
L. Y. Chan ◽  
R. J. Clark ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Cyclic Peptide ◽  
Sequence Similarity ◽  
Infection Model ◽  
Content Type ◽  
Wide Range ◽  
Inhibitory Activities ◽  
The Impact

ABSTRACTStaphylococcus aureusis a virulent pathogen that is responsible for a wide range of superficial and invasive infections. Its resistance to existing antimicrobial drugs is a global problem, and the development of novel antimicrobial agents is crucial. Antimicrobial peptides from natural resources offer potential as new treatments against staphylococcal infections. In the current study, we have examined the antimicrobial properties of peptides isolated from anuran skin secretions and cyclized synthetic analogues of these peptides. The structures of the peptides were elucidated by nuclear magnetic resonance (NMR) spectroscopy, revealing high structural and sequence similarity with each other and with sunflower trypsin inhibitor 1 (SFTI-1). SFTI-1 is an ultrastable cyclic peptide isolated from sunflower seeds that has subnanomolar trypsin inhibitory activity, and this scaffold offers pharmaceutically relevant characteristics. The five anuran peptides were nonhemolytic and noncytotoxic and had trypsin inhibitory activities similar to that of SFTI-1. They demonstrated weakin vitroinhibitory activities againstS. aureus, but several had strong antibacterial activities againstS. aureusin anin vivomurine wound infection model. pYR, an immunomodulatory peptide fromRana sevosa, was the most potent, with complete bacterial clearance at 3 mg · kg−1. Cyclization of the peptides improved their stability but was associated with a concomitant decrease in antimicrobial activity. In summary, these anuran peptides are promising as novel therapeutic agents for treating infections from a clinically resistant pathogen.

Trace CO elimination in H2-rich streams with wide operation temperature window: Co deposited CuO-CeO2 catalysts

2021 ◽  
Author(s):  
Zhihuan Qiu ◽  
Xiaolin Guo ◽  
Jianxin Mao ◽  
Renxian Zhou
Keyword(s):  
Fuel Cells ◽  
Hydrogen Fuel Cells ◽  
Hydrogen Fuel ◽  
Operation Temperature ◽  
New Strategy ◽  
Temperature Window

This work provides a new strategy to eliminate the trace CO in H2-rich gas in a wide operation temperature window for the application of hydrogen fuel cells. We engineered Co...

Sign in / Sign up

Export Citation Format

Share Document