LOX/GOX sensitivity of fluoroelastomers

The effect of formulation components and the addition of fire retardants on the impact sensitivity of Viton B fluoroelastomer in liquid oxygen was studied with the objective of developing a procedure for reliably reducing this sensitivity. Component evaluation, carried out on more than 40 combinations of components and cure cycles, showed that almost all the standard formulation agents, including carbon, MgO, Diak-3, and PbO2, will sensitize the Viton stock either singly or in combinations, some combinations being much more sensitive than others. Cure and postcure treatments usually reduced the sensitivity of a given formulation, often dramatically, but no formulated Viton was as insensitive as the pure Viton B stock. Coating formulated Viton with a thin layer of pure Viton gave some indication of reduced sensitivity, but additional tests are needed. It is concluded that sensitivity in formulated Viton arises from a variety of sources, some physical and some chemical in origin. Elemental analyses for all the formulated Vitons are reported as are the results of a literature search on the subject of LOX impact sensitivity

Investigation of the reactivity of organic materials in liquid oxygen

Measurements of impact-ignition sensitivity and studies of the relative reactivity of t-butoxy and t-butyl peroxy radicals toward a variety of organic compounds reveal improved methods of selection of materials for safe use in a liquid oxygen environment

Diversidad gen?tica de potamotrygon motoro en las cuencas del Onrin?co y Amazonas colombiano

61 p. Recurso Electr?nicoLa falta de claridad frente a la taxonom?a de Potamotrygon motoro y la ausencia de estudios previos de su diversidad gen?tica, hace a la especie vulnerable al ser la segunda especie de raya de agua dulce m?s extra?da y exportada con fines ornamentales en Colombia. El objetivo de este trabajo fue determinar la estructura y la diversidad gen?tica intra e inter poblacional para P. motoro en las cuencas del Orinoco y Amazonas Colombiano. Se analizaron un total de 110 muestras colectadas por el Instituto Alexander von Humboldt correspondientes a cinco puntos de muestreo en la cuenca del Orinoco y dos puntos de muestreo en la cuenca del Amazonas. Se realiz? la amplificaci?n de los genes mitocondriales Citocromo Oxidasa sub unidad I (COI) y Citocromo b (Cytb) y se elabor? una red haplot?pica para cada gen, se realizaron an?lisis moleculares de varianza y se evalu? un K probable por medio de inferencia bayesiana. Se encontr? un haplotipo compartido entre cuencas ?nicamente para la red construida para el gen COI. Se encontr? un K = 4, diferenciando 3 de las 4 unidades por cuencas. Se observ? un alto valor de Fst al contrastar las dos cuencas, indicando una alta diferenciaci?n gen?tica (COI = 0.456; Cytb = 0.388) entre estas. Estos resultados sugieren replantear los planes de conservaci?n y manejo de la especie en Colombia. Palabras clave: Potamotrygon motoro, ADN mitocondrial, gen?tica poblacional.The lack of clarity regarding the taxonomy of the Potamotrygon motoro And the absence of previous studies of its genetic diversity, makes the species vulnerable to being the second species of freshwater ray most extracted and exported for ornamental purposes in Colombia. Thus, this study aimed to analyze the genetic structure and the genetic diversity of populations colonizing Potamotrygon motoro found in the Orinoco and Amazon Rivers in Colombia. A hundred ten individuals were Collected for the Instituto Alexander von Humboldt, all the individuals were sequenced for COI and Cytb, We made a haplotipic net for each gen and a representative subsample of 38 individuals was concatenated to evaluate K using BAPS. We found a haplotipic sharing between the Orinoco and Amazonas for the COI net. We found a K =4, and 3 of the 4 possibilities are different between the Orinoco and Amazonas Basin. It was a high value of fast, it shows a high genetic differentiation (COI = 0.456; Cytb = 0.388) between basins. This result suggest to make a new conservation strategies for the specie in Colombia. Keywords: Potamotrygon motoro, Mitochondrial DNA, Population genetics

Investigation of reactivity of launch vehicle materials with liquid oxygen Quarterly report, 23 Jul. - 22 Oct. 1968

Reactivity of launch vehicle organic materials with liquid oxyge

Investigation of Reactivity of Launch Vehicle Materials with Liquid Oxygen

Impact sensitivity and ignition mechanism of organic compounds in liquid oxygen correlated with chemical and physical propertie

The McKinsey-Tarski theorem for locally compact ordered spaces

We prove that the modal logic of a crowded locally compact generalized ordered space is S4. This provides a version of the McKinsey–Tarski theorem for generalized ordered spaces. We then utilize this theorem to axiomatize the modal logic of an arbitrary locally compact generalized ordered space