Nanotomography based study of gas diffusion layers

Stochastic reconstruction of carbon fiber paper gas diffusion layers of PEFCs: A comparative study

A 3D microstructure of the non-woven gas diffusion layers (GDLs) of polymer electrolyte fuel cells (PEFCs) is reconstructed using a stochastic method. For a commercial GDL, due to the planar orientation of the fibers in the GDL, 2D SEM image of the GDL surface is used to estimate the orientation of the carbon fibers in the domain. Two more microstructures with different fiber orientations are g...

Study of Gas Diffusion Layers in Pem Fuel Cells

Fuel cells are electrochemical devices which convert chemical energy of a reacting fuel directly into electricity with high efficiency and no pollution. Proton Exchange/ Polymer Electrolyte Membrane (PEM) fuel cells are likely to be among one of the most promising energy sources for transportation, heating and power generation. Some of the key materials used in PEM fuel cells are catalysts, mem...

study of hash functions based on chaotic maps

توابع درهم نقش بسیار مهم در سیستم های رمزنگاری و پروتکل های امنیتی دارند. در سیستم های رمزنگاری برای دستیابی به احراز درستی و اصالت داده دو روش مورد استفاده قرار می گیرند که عبارتند از توابع رمزنگاری کلیددار و توابع درهم ساز. توابع درهم ساز، توابعی هستند که هر متن با طول دلخواه را به دنباله ای با طول ثابت تبدیل می کنند. از جمله پرکاربردترین و معروف ترین توابع درهم می توان توابع درهم ساز md4, md...

Experimental characterization of in-plane permeability of gas diffusion layers

Recent studies indicate that PEM fuel cell performance may be strongly influenced by in-plane permeability of the gas diffusion layer (GDL). The urrent study employs a radial flow technique for obtaining in-plane permeability of GDLs, using either gas or liquid as the impregnating fluid. A odel has been developed and experimentally verified to account for compressibility effects when permeabili...

Three-dimensional Study of Compressed Gas Diffusion Layers using Synchrotron X-ray Imaging