Theoretical models of Kapton heating in solar array geometries

In an effort to understand pyrolysis of Kapton in solar arrays, a computational heat transfer program was developed. This model allows for the different materials and widely divergent length scales of the problem. The present status of the calculation indicates that thin copper traces surrounded by Kapton and carrying large currents can show large temperature increases, but the other configurations seen on solar arrays have adequate heat sinks to prevent substantial heating of the Kapton. Electron currents from the ambient plasma can also contribute to heating of thin traces. Since Kapton is stable at temperatures as high as 600 C, this indicates that it should be suitable for solar array applications. There are indications that the adhesive sued in solar arrays may be a strong contributor to the pyrolysis problem seen in solar array vacuum chamber tests

Information Aggregation and Strategic Abstention in Large Laboratory Elections

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Efficiency, Equity, and Timing in Voting Mechanisms

We compare the behavior of voters, depending on whether they operate under sequential and simultaneous voting rules, when voting is costly and information is incomplete. In many real political institutions, ranging from small committees to mass elections, voting is sequential, which allows some voters to know the choices of earlier voters. For a styl- ized model, we characterize the equilibria for this rule, and compare it to simultaneous voting, and show how these equilibria vary for di¤erent voting costs. This generates a variety of predictions about the relative e¢ ciency and equity of these two systems, which we test using controlled laboratory experiments. Most of the qualitative predictions are supported by the data, but there are signi?cant departures from the predicted equilib- rium strategies, in both the sequential and sumultanous voting games. We ?nd a tradeo¤ between information aggregation, e¢ ciency, and equity in sequential voting: a sequential voting rule aggregates information better, and produces more e¢ cient outcomes on aver- age, compared to simultaneous voting, but sequential voting leads to signi?cant inequities, with later voters ben?tting at the expense of early voters.

New English Canaan

In 1883 the Prince Society published in very limited quantity The New English Canaan edited by Charles Francis Adams. Since then there has been no new edition of this informative and entertaining work. Adams held faithfully to the original in spelling, punctuation, and even in the use of the early in the text. His footnotes are learned, copious, and occasionally a bit irrelevant, but a number of mystifying expressions are not explained. It may simply be the short supply and relatively poor readability that have caused modern scholars to deny Morton’s work the attention that it deserves. In this edition I have attempted at least a partial remedy of the above by making it more readily readable without doing serious violence to the seventeenth century flavor of the original

C-Cl Bond Fission, Hcl Elimination, And Secondary Radical Decomposition In The 193 Nm Photodissociation Of Allyl Chloride

The primary photodissociation dynamics of allyl chloride upon excitation at 193 nm is investigated in a crossed laser-molecular beam scattering apparatus. Tunable vacuum ultraviolet (VUV) photoionization of the products provides a unique ability to learn about the secondary reaction products of the nascent photoproducts formed. The data show evidence for four significant primary reaction channels: a previously unidentified low kinetic energy C-Cl bond fission channel producing unstable allyl radicals, an excited state C-Cl bond fission channel producing Cl atoms with high translational energy, an HCl elimination pathway releasing significant energy to product translation to HCl and its momentum-matched mass 40 partner, and an HCl elimination channel producing low kinetic energy HCl products and predominantly unstable mass 40 products. The measured branching of these primary reaction channels of [all C-Cl] : [fast C-Cl] : [slow C-Cl] : [fast HCl] : [slow HCl] : [all HCl] is 1.00: 0.971: 0.029: 0.291: 0.167: 0.458 (where fast refers to the high recoil kinetic energy channels). The high internal energy allyl radicals formed in the slow C-Cl fission pathway of allyl chloride further dissociate/isomerize, as do the unstable mass 40 products formed in the HCl elimination pathways, and these products are investigated. Photoionization efficiency (PIE) curves of the HCl product suggest that a three-centered elimination mechanism contributes significantly to an observed HCl elimination reaction. (C) 2002 American Institute of Physics