Extinguishing in-flight engine fuel-leak fires with dry chemicals

The fire extinguishant storage temperature requirements were examined for several commercially available dry chemicals. Particular emphasis was placed on the development of dry powder extinguishant that, when discharged into a jet engine fuel leak fire, would stick to the hot surfaces. Moreover, after putting out the initial fire, these extinguishants would act as antireignition catalysts, even when the fuel continued to leak onto the heated surface

Method for evaluating effectiveness of dry fire-extinguishing chemicals

Apparatus used in method is commercially available, powder-deposition type oxy-acetylene torch that has been modified to provide electronically timed operations and more uniform powder flow; usual torch tips are replaced by burner head with pilot flame

Synthesis of dawsonites

Alkali metal and ammonium dawsonites can be prepared by a nonaqueous process according to which equimolar quantities of the corresponding hydrogen carbonate and aluminum hydroxide in finely divided state are heated together to a tempeature within the range of 150 to 250 C, for a period of 1 to 6 hours under a carbon dioxide pressure within the range of 120 to 360 psig. Carbonates may be used instead of hydrogencarbonates

Noise Correlations in one-dimensional systems of ultra-cold fermions

Time of flight images reflect the momentum distribution of the atoms in the trap, but the spatial noise in the image holds information on more subtle correlations. Using Bosonization, we study such noise correlations in generic one dimensional systems of ultra cold fermions. Specifically, we show how pairing as well as spin and charge density wave correlations may be identified and extracted from the time of flight images. These incipient orders manifest themselves as power law singularities in the noise correlations, that depend on the Luttinger parameters, which suggests a general experimental technique to obtain them.Comment: 5 pages, 3 figures. Added discussion on the visibility of noise correlation features for realistic condition

Research Opportunities in Nutrition and Metabolism in Space

The objectives of the Life Sciences Research Office (LSRO) study on nutrient requirements for meeting metabolic needs in manned space flights are as follows: review extant knowledge on the subject; identify significant gaps in knowledge; formulate suggestions for possible research; and produce a documented report of the foregoing items that can be used for program planning. In accordance with NASA's request for this study, the report focuses on issues of nutrition and metabolism that relate primarily to the contemplated United States Space Station, secondarily to the Shuttle Program as an orbital test bed for operational studies, and incidentally to scenarios for future long-term space flights. Members of the LSRO ad hoc Working Group on Nutrition and Metabolism were provided with pertinent articles and summaries on the subject. At the meeting of the Working Group, presentations were made by NASA Headquarters program staff on past experiences relative to space-flight nutrition and metabolism, as well as scenarios for future flights. The discussions of the ad hoc Working Group focused on the following: (1) metabolic needs related to work and exercise; (2) nutrients required to meet such needs; (3) food types, management, and records; and (4) nutritional amelioration or prevention of space-related physiological and behavioral changes

Fire extinguishant materials

Fire extinguishant composition comprising a mixture of a finely divided aluminum compound and alkali metal, stannous or plumbous halide is provided. Aluminum compound may be aluminum hydroxide, alumina or boehmite but preferably it is an alkali metal dawsonite. The metal halide may be an alkali metal, e.g. potassium iodide, bromide or chloride or stannous or plumbous iodide, bromide or chloride. Potassium iodide is preferred

Branching processes, the max-plus algebra and network calculus

Branching processes can describe the dynamics of various queueing systems, peer-to-peer systems, delay tolerant networks, etc. In this paper we study the basic stochastic recursion of multitype branching processes, but in two non-standard contexts. First, we consider this recursion in the max-plus algebra where branching corresponds to finding the maximal offspring of the current generation. Secondly, we consider network-calculus-type deterministic bounds as introduced by Cruz, which we extend to handle branching-type processes. The paper provides both qualitative and quantitative results and introduces various applications of (max-plus) branching processes in queueing theory