Economic Analysis of an Integrated Wind-Hydrogen Energy System for a Small Alaska Community

Wind-hydrogen systems provide one way to store intermittent wind energy as hydrogen. We explored the hypothesis that an integrated wind-hydrogen system supplying electricity, heat, and transportation fuel could serve the needs of an isolated (off-grid) Alaska community at a lower cost than a collection of separate systems. Analysis indicates that: 1) Combustible Hydrogen could be produced with current technologies for direct use as a transportation fuel for about $15/gallon-equivalent; 2) The capital cost of the wind energy rather than the capital cost of electrolyzers dominates this high cost; and 3) There do not appear to be diseconomies of small scale for current electrolyzers serving a a village of 400 people.United States Department of Energy. DOE Award Number: DE-FC26-01NT41248Introduction / Executive Summary / Experimental Methods / Results and Discussion / Conclusion / Bibliography / Appendix: Associated Excel Workbook

Using twins and scaling to construct cospectral graphs for the normalized Laplacian

The spectrum of the normalized Laplacian matrix cannot determine the number of edges in a graph, however finding constructions of cospectral graphs with differing number of edges has been elusive. In this paper we use basic properties of twins and scaling to show how to construct such graphs. We also give examples of families of graphs which are cospectral with a subgraph for the normalized Laplacian matrix

The End of Affirmative Action? Work Rule Concessions at South Works

[Excerpt] The recent Rail Mill Manning Agreement between U.S. Steel South Works and Local 65 of the United Steelworkers of America changed both the local and Basic Labor Agreements. This paper will demonstrate the adverse effect that this Agreement will have on minorities and women

Addendum: Level Spacings for Integrable Quantum Maps in Genus Zero

In this addendum we strengthen the results of math-ph/0002010 in the case of polynomial phases. We prove that Cesaro means of the pair correlation functions of certain integrable quantum maps on the 2-sphere at level N tend almost always to the Poisson (uniform limit). The quantum maps are exponentials of Hamiltonians which have the form a p(I) + b I, where I is the action, where p is a polynomial and where a,b are two real numbers. We prove that for any such family and for almost all a,b, the pair correlation tends to Poisson on average in N. The results involve Weyl estimates on exponential sums and new metric results on continued fractions. They were motivated by a comparison of the results of math-ph/0002010 with some independent results on pair correlation of fractional parts of polynomials by Rudnick-Sarnak.Comment: Addendum to math-ph/000201