Mechanisms of polymer degradation using an oxygen plasma generator

An RF oxygen plasma generator was used to produce polymer degradation which appears to be similar to that which has been observed in low Earth orbit. Mechanisms of this type of degradation were studied by collecting the reaction products in a cryogenic trap and identifying the molecular species using infrared, mass spectral, and X-ray diffraction techniques. No structurally dependent species were found from Kapton, Teflon, or Saran polymers. However, very reactive free radical entities are produced during the polymer degradation, as well as carbon dioxide and water. Reactions of the free radicals with the glass reaction vessel, with copper metal in the cold trap, and with a triphenyl phosphate scavenger in the cold trap, demonstrated the reactivity of the primary products

Investigation of conductive thermal control coatings by a contactless method in vacuo

A technique for determining the conductance per unit area of thermal control coatings for electrostatically clean spacecraft is described. In order to simulate orbital conditions more closely, current-density-voltage (j-V) curves are obtained by a contactless method in which the paint on an aluminum substrate is the anode of a vacuum diode configuration with a tungsten filament cathode. Conductances per unit area which satisfy the International Sun Earth Explorer (ISEE) requirement were observed on black paints containing carbon and in white and green paints filled with zinc oxide which were fired in order to induce defect conductivity. Because of surface effects and the nonhomogeneous nature of paints, large discrepancies were found between measurements with the contactless method and measurements employing metallic contacts, particularly at low current densities. Therefore, measurements with metallic contacts are considered to be of questionable value in deciding the suitability of coatings for electrostatic charge control

Isospin-Violating Dark Matter Benchmarks for Snowmass 2013

Isospin-violating dark matter (IVDM) generalizes the standard spin-independent scattering parameter space by introducing one additional parameter, the neutron-to-proton coupling ratio f_n/f_p. In IVDM the implications of direct detection experiments can be altered significantly. We review the motivations for considering IVDM and present benchmark models that illustrate some of the qualitatively different possibilities. IVDM strongly motivates the use of a variety of target nuclei in direct detection experiments.Comment: LaTeX, 5 pages, 4 figures. v2: minor figure revision

Isospin-Violating Dark Matter

Searches for dark matter scattering off nuclei are typically compared assuming that the dark matter's spin-independent couplings are identical for protons and neutrons. This assumption is neither innocuous nor well motivated. We consider isospin-violating dark matter (IVDM) with one extra parameter, the ratio of neutron to proton couplings, and include the isotope distribution for each detector. For a single choice of the coupling ratio, the DAMA and CoGeNT signals are consistent with each other and with current XENON constraints, and they unambiguously predict near future signals at XENON and CRESST. We provide a quark-level realization of IVDM as WIMPless dark matter that is consistent with all collider and low-energy bounds.Comment: 5 pages; v2: added references and fixed figures for Mac users; v3: published version; v4: fixed erroneous Ar values in table

Mathematics and German politics: The national socialist experience

AbstractDuring the Nazi period in Germany, an attempt was made to discern a kind of mathematics that was German as distinct from other ethnic or “racial” types of mathematics: a “Deutsche Mathematik.” While not denying the universal validity of all mathematical truths, such a “German” mathematics stressed ideology in terms of research and pedagogical styles. Because mathematics was nearly independent of anything material, it was—for the “Deutsche Mathematiker”—especially amenable to the Nazi argument that different racial psychological types exhibit different racial characters and modes of thought. This paper is a brief examination of the nature and intellectual content of “Deutsche Mathematik.

A comparison of the revised Stanford-Binet scale and the Terman-McNemar test of mental ability with respect to the prediction of scholastic achievement

Although more than fifty years have passed since the Frenchmen Alfred Binet and Theophile Simon published the first effective intelligence test, psychological testing has evolved through many stages since that time. There are many different types of psychological tests now, with numerous methods of interpretation. However, through all of this evolution the basic purpose of the tests has remained the same— to measure Individual differences. Just as Binet and Simon\u27s first intelligence test . . . succeeded in differentiating between children of various age and grade levels and made possible the prediction of the child\u27s progress in school, so psychological tests are still used for this purpose In our schools today

The Origins and Development of Higher Education for Negros in South Carolina to 1920

The term higher education for Negroes is usually applied to that intellectual training received by Negroes after the time of Emancipation and Reconstruction when inspired missionaries and democratic legislatures first established schools for the education of the ex-slaves. That this period marked the beginning of a systematized method of lifting the veils of ignorance from the eyes of the freedman is not to be doubted. It may be historically incorrect, however, to designate these efforts as the first attempts to educate the Negro, and especially may this be true with regard to the appellation higher education