Browsing by Subject "Ion-permeable membranes"
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Item A basic model of hydrogen circulation in a proton exchange membrane (PEM) fuel cell(Texas Tech University, 1999-12) Akgerman, BoraThe fuel cell has come a long way since Sir Hubert Davy built the first prototype in 1801. After a slow 150 years, the fuel cell came to the attention of the world with the first slew of fuel cell operated vehicles in the 1950's. The next decade saw fuel cells used in NASA's Gemini and Apollo space missions. The 1990's have seen fuel cells in power plants, city busses, and space shuttle missions. Currently, $1 billion has been invested worldwide to investigate fuel cell operated vehicles as an alternate to Internal Combustion Engine (ICE) operated vehicles. With fuel cell efficiencies nearing 50%, low emissions and better reliability, fuel cell research is at an all-time high. This research will investigate the performance of the hydrogen circulation system of a Proton Exchange Membrane (PEM) fuel cell specifically designed for a hybrid vehicle. System parameters will be analyzed to find the optimum operating conditions for the hydrogen circulation system.Item Evaluating the power capabilities of a hydrogen fuel cell(Texas Tech University, 1999-05) Turner, Wallace D. L.The hydrogen fuel cell has become a very important dc source that has many applications including transportation, power stations, and space missions. The voltage per cell is limited, however, the current density per surface area is very large. So, very high power can be produced from a fuel cell with a low voltage. This thesis describes testing done on a solid polymer proton exchange membrane fuel cell that produces 1 volt maximum per cell with 300A test maximum load. The focus of this report deals with evaluating the power capabilities and characteristics of the 4 cell stack using a test stand. In this effort, it is possible to understand the implications of implementing a one hundred, and ten cells stack into an automobile.Item Synthesis of new crown ether compounds(Texas Tech University, 1999-05) Zhang, QianIn 1967, Pedersen published the first practical synthesis of a variety of cyclic polyether compounds and assessed their complexation abilities for alkali and alkaline-earth metal ions. As shown in Equation 1.2, when Pedersen tried to prepare bisphenol 4 from bis(2-chloroethyl) ether and monotetrahydropyranylprotected catechol, which was contaminated with 10% of unprotected catechol, a small amount of white crystalline solid with a silky, fibrous nature was obtained as a by-product. The structure of this by-product was deduced to be crown ether 5 by elemental and mass spectroscopic analysis. Pedersen found that the yield of crown ether 5 could be increased to 45% when pure catechol was utilized as a reactant. Subsequently Pedersen prepared more than 60 macrocyclic polyethers and investigated the formation of complexes between the cyclic polyethers and metal salts. For his work, Pedersen together with Cram and Lehn was awarded the 1987 Nobel Prize in Chemistry.