Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Engineering
A Finite-Difference Method For Pseudo-Two-Dimensional Boundary Value Problems, Z. Mao, Ralph E. White
A Finite-Difference Method For Pseudo-Two-Dimensional Boundary Value Problems, Z. Mao, Ralph E. White
Ralph E. White
A finite-difference method is presented for solving pseudo-two-dimensional boundary-value problems. The sparse and nearly block tridiagonal properties of the matrices generated by using the finite-difference method for problems of this type are fully utilized and maintained, which yields a method that is highly efficient in the use of storage space and computation. An example shows that the central process unit time required by the method is significantly less than that required by an alternative method.
Electrochemical Characterization Of Electronically Conductive Polypyrrole On Cyclic Voltammograms, Taewhan Yeu, Ken-Ming Yin, Jose Carbajal, Ralph E. White
Electrochemical Characterization Of Electronically Conductive Polypyrrole On Cyclic Voltammograms, Taewhan Yeu, Ken-Ming Yin, Jose Carbajal, Ralph E. White
Ralph E. White
Experimental and theoretical cyclic voltammograms for electronically conducting polypyrrole film are obtained from the identical conditions and compared to each other to characterize electrochemical behavior of the polymer. A comparison of the simulated and experimental cyclic yoltammograms shows quantitative agreement. The profiles of the dependent variables show that the switching process is governed by the availability of the counter ion to the polypyrrole electrode and the amount of electroactive sites. Sensitivity analysis shows that the double layer effects have more influence in the cyclic voltammograms than the electrokinetic effects.
Electrochemical Investigations Of Cobalt-Doped Limn2O4 As Cathode Material For Lithium-Ion Batteries, P. Arora, Branko Popov, Ralph E. White
Electrochemical Investigations Of Cobalt-Doped Limn2O4 As Cathode Material For Lithium-Ion Batteries, P. Arora, Branko Popov, Ralph E. White
Ralph E. White
A wide range (y = 0.05–0.33) of Co-doped LiCoyMn2–yO4 spinels were synthesized and electrochemically characterized. These Co-doped spinels showed improved specific capacity and capacity retention over pure spinels. Electrochemical impedance spectroscopy and the linear polarization resistance technique were used to determine the transport and electrochemical kinetic parameters of Co-doped spinels. The presence of Co in the spinel inhibits the passivation process occurring on the surface of the cathode. Also, Co increases the exchange current density and facilitates the charge-transfer reaction of the active material. The lower self-discharge observed for Co-doped spinels was attributed …
A Mathematical Model Of The Self-Discharge Of A Ni-H2 Battery, Z. Mao, Ralph E. White
A Mathematical Model Of The Self-Discharge Of A Ni-H2 Battery, Z. Mao, Ralph E. White
Ralph E. White
A simple mathematical model is presented and used to characterize the self-discharge of a nickel oxyhydroxide(NiOOH) electrode in a hydrogen environment. This model includes diffusion of dissolved hydrogen in an electrolyte film which covers a flooded electrode, electrochemical oxidation of hydrogen, reduction of nickel oxyhydroxide, and changes of surface area and of porosity of the electrode during the self-discharge process. Although the self-discharge process is complicated, the predictions of the model are consistent with experimental results reported in the literature, which include linear relationships between the logarithm of hydrogen pressure and time and between the logarithm of the capacity remaining …