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Chemical vapour deposition of ultrafine particles
Published in Kwang Leong Choy, Chemical Vapour Deposition (CVD), 2019
For the application of fuel cells, proton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells (PEMFCs), are a type of fuel cell being developed for transport applications as well as for stationary and portable fuel cell applications. Currently, Pt nanoparticles are used as catalysts, as nanoparticles exhibit high surface-to-weight ratios, thereby reducing the amount of the costly platinum. For this type of applications, ALD method has an advantage on the controllable deposition as compared with thin-film method and electrodeposition method in terms of simple processing, large area, batch production, small particle size, lower loading, good uniformity, and conformality. In particular, conformal coating of Pt with controlled particle size is required in the case of micro fuel cells, for lower loading (e.g., 0.016 mg cm−2 by ALD as compared to >0.1 mg cm−2 in liquid process) and uniformity [66]. As ALD has not been used to make large volume production of ultrafine particles, more research is needed for this application.
P
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
protocol data unit (PDU) the unit of exchange of protocol information between entities. Typically, a PDU is analogous to a structure in C or a record in Pascal; the protocol in executed by processing a sequence of PDUs. protocol spoofing a technique used by VSAT networks to reduce the network delay. The satellite network emulates the host computer front-end processor at the VSAT locations and emulates the multiple cluster controllers at the hub location. proton exchange membrane fuel cell (PEMFC) a fuel cell that uses a plastic membrane as its electrolyte. Also called solid polymer fuel cell (SPFC). See alkaline fuel cell, phosphoric acid fuel cell, molten carbonate fuel cell, solid oxide fuel cell. prototype filter a low-pass filter which is modulated to form a modulated filter bank. prototyping building an engineering model of all or part of a system to prove that the concept works. proximity effect a variation in the size of a printed feature as a function of the sizes and positions of nearby features. proximity printing a lithographic method whereby a photomask is placed in close proximity (but not in contact) with a photoresist coated wafer and the pattern is transferred by exposing light through the photomask into the photoresist. pruning self-generating neural network a methodology for reducing the size of selfgenerating neural network (SGNN). During SGNN training, the network may grow very quickly, and some parts of the network may
A critical review of fuel cell commercialization and its application in desalination
Published in Hacene Mahmoudi, Noreddine Ghaffour, Mattheus Goosen, Jochen Bundschuh, Renewable Energy Technologies for Water Desalination, 2017
Yousef Alyousef, Mattheus Goosen, Youssef Elakwah
Kim et al. (2015) prepared a review of polymer-nanocomposite electrolyte membranes for fuel cell applications. From their analysis they concluded that given the design of suitable polymer composites it is possible to provide long-term durability and better electrical properties, such as current density, of the polymer electrolyte membrane. The working principle of the fuel cell is illustrated schematically in Figure 9.2. Currently, polymer electrolyte membrane fuel cells are based on perfluorosulfonic acid membranes such as Nafion and Flemion, which have shortcomings in terms of proton conductivity, durability, thermal stability, maximum power density and fuel crossover, and cost. In recent years, the hybrid organic-inorganic composite membrane has emerged as an interesting alternative. It provides a unique combination of organic and inorganic properties, and overcomes the limitations of the pure polymeric membranes. Among the various fuel cell systems, solid proton exchange membrane fuel cells (PEMFC) can be applied to small-scale applications such as automotive, portable power generation, and stationary equipment (Fig. 9.1 and Fig. 9.2). The power-generating system in PEMFCs is an electrochemical reaction involving gases such as hydrogen, methanol and ethanol. The reactions occurring in the fuel cell can be described as follows:
Droplet dynamic behaviors on gas diffusion layer surface of various wettabilities in a PEMFC gas flow channel
Published in International Journal of Green Energy, 2021
Yulin Wang, Tao Liu, Huan Sun, Minchao Yao, Shengchun Liu, Yanzhou Qin, Xiaodong Wang
Proton exchange membrane fuel cell (PEMFCs) have the potential to be used as the power sources for automobiles, power stations, etc., due to its high-power density, low-temperature start-up capability, and clean operation. Although great progress has been made in the fundamental research on the application of PEMFCs, their costs, lifetime, stability, and output performance still need to be further improved for their full commercialization. Appropriate water management is deemed to be an effective method to achieve a PEMFC of high output performance and stability (Jiao and Li 2011; Golpaygan and Ashgriz 2005). As key components of PEMFCs, gas flow channel (GFC) and gas diffusion layer (GDL) play significant roles in maintaining water balance within PEMFCs (Park et al. 2004; Quan and Lai 2007).
Experimental analysis of PEM fuel cell performance using lung channel design bipolar plate
Published in International Journal of Green Energy, 2019
Srinivasa Reddy Badduri, G. Naga Srinivasulu, S. Srinivasa Rao
Fuel cell is a device which transforms the chemical energy of a fuel into useful electrical energy by means of electrochemical effect. Proton exchange membrane fuel cells (PEMFCs) have the characteristics of high efficiency, small volume, short start-up time, low noise, and low emission, and have been used in power plants, vehicles, and Combined Cooling, Heating and Power generation (CCHP) buildings. However, PEMFCs must overcome various challenges related to performance, cost and durability, before they can be used as commercial feasible alternatives for transportation (Ahluwalia et al. 2011; Ahn et al. 2013; Akhtar and Kerkhof 2011; Inman et al. 2011) technologies and portable applications. Design of the flow channel in a bipolar plate is the most essential aspect in order to achieve good performance (Guo, Leu, and Koylu 2014). The important role of bipolar plates in PEMFCs is to provide dynamic stability to the whole assembly, distribute the reactants uniformly, conduct current through the lands, and remove product gasses and liquid water. The current research on PEMFC is to optimize the flow channel design and material of bipolar plates to enrich the performance of PEMFC (Cooper et al. 2016; Nguyen 1996). For better electrical and mechanical properties, graphite bipolar plate is prepared by using selective laser sintering (SLS) technology.
Experimental analysis of an integrated biomass gasification and PEM fuel cell system
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
According to the present author’s knowledge, no considerable research has been reported on integrated biomass gasification and PEM fuel cell using high-pressure fluidized bed with a mixture of air and steam as a gasifying agent. Chutichai et al. (2013) designed an integrated biomass gasification and PEM fuel cell using Aspen Plus simulator for residential applications, taking zero-emission energy demands into account. The authors explored the effects of some critical factors on performance parameters such as load level and operating conditions (steam/biomass ratio (S/B) and pressure). The feasibility of generating electricity on a small scale gasifier linked to a PEM fuel cell was studied by the US National Renewable Energy Laboratory (NREL) (Amos 1998). The capital cost for the integrated gasifier and PEM fuel cell was calculated to be about $15.0 million, including $4.8 million for the PEM fuel cell which is relatively expensive compared to other energy systems, but there is no other choice for some of the special applications such as space programs and portable applications (Barbir 2005).