Browsing by Subject "Fuel cells"

Now showing 1 - 3 of 3

Open Access
Model-in-the-loop development for fuel cell vehicle
(IEEE, 2011) Çakmakçı, Melih; Li, Y.; Liu, S.
In this paper, the work on developing and validating a model-in-the-loop (MIL) simulation environment for a group of prototype fuel cell vehicles is presented. The MIL model consists of a vehicle plant model and an integrated vehicle system controller model. First, the vehicle simulation plant model is functionally validated with a simple vehicle system controller (VSC) model and then improved to satisfy the input output interface and fidelity requirements. The developed MIL system is then verified for basic functionality against the simple VSC controller model and shows uniform correlation results. It is further validated against vehicle dynamometer test data and demonstrates satisfactory consistency. A rapid model building approach which is suitable for model-based controller design process was also discussed. This approach enabled the developers to use model-to-code algorithms unlike many comparable simulation models. © 2011 AACC American Automatic Control Council.
Open Access
Modification of the Fe,Co–N/C catalysts for oxygen reduction reaction by a chemical post-treatment with oxidizing agents
(Elsevier Ltd, 2023-11-17) Lastovina, Tatiana; Bugaev, A.; Fedorenko, A.; Nikolskiy, A.; Kozakov, A.; Anokhin, A.; Yohannes, W.; Budnyk, Andriy
The transition-metals carbon catalysts belong to intensively studied alternatives to the Pt-based catalysts promoting the oxygen reduction reaction (ORR) in electrochemical fuel cells (FCs). Commonly studied Fe,Co–N–C composites are usually obtained through pyrolysis and used as such or after a chemical post-treatment with an oxidizing agent. This treatment is applied to remove inactive metal species, thus, promoting the electrochemical activity. The impact of an oxidizing agent is poorly addressed in the literature, while its nature may negatively affect the catalyst's performance. Herein we report the first comparative study on the effect of post-treatment with the most common oxidizing agents such as HCl, HNO3, H2SO4 and H2O2, on the structural and electrochemical properties of the Fe,Co–N–C catalyst. The catalyst is made by pyrolysis of the Co,Zn-ZIF metal-organic framework enriched with iron and nitrogen. Its structure was observed withstanding the action of mineral acids but suffers from hydrogen peroxide. The treatment with either nitric or chloric acid may improve the electrochemical performance up to 4%, while other agents decrease that by 6% and slow down the ORR rate. These findings are useful for the careful design of post-treatment procedures for carbon catalysts.
Open Access
Spiral microfluidics device for continuous flow PCR
(ASME, 2013) Salemmilani, Reza; Çetin, Barbaros
Polymerase-chain-Reaction (PCR) is a thermal cycling (repeated heating and cooling of PCR solution) process for DNA amplification. PCR is the key ingredient in many biomedical applications. One key feature for the success of the PCR is to control the temperature of the solution precisely at the desired temperature levels required for the PCR in a cyclic manner. Microfluidics offers a great advantage over conventional techniques since minute amounts of PCR solution can be heated and cooled with a high rate in a controlled manner. In this study, a microfluidic platform has been proposed for continuous-flow PCR. The microfluidic device consists of a spiral channel on a glass wafer with integrated chromium microheaters. Sub-micron thick microheaters are deposited beneath the micro-channels to facilitate localized heating. The microfluidic device is modeled using COMSOL MultiphysicsR . The fabrication procedure of the device is also discussed and future research directions are addressed. With its compact design, the proposed system can easily be coupled with an integrated microfluidic device to be used in biomedical applications. Copyright © 2013 by ASME.