Emergency egress requirements for caution and warning, logistics, maintenance, and assembly stage MB-6 of Space Station Freedom

The safety and survival of the crewmembers has been the prime concern of NASA. Previous studies have been conducted mainly for emergencies occurring during the operating mode of the fully assembled Station. The present study was conducted to evaluate the emergency requirements for the caution and warning, logistics, maintenance, and assembly stage MB-6 of the Station in space. Effective caution and warning is essential to achieve safe egress in emergencies. In order to survive a long period in space, the safety and emergency requirements for maintenance, logistics, and extravehicular assembly operation in space must be met

Emergency egress requirements for Space Station Freedom

There is a real concern regarding the requirements for safe emergency egress from the Space Station Freedom (SSF). The possible causes of emergency are depressurization due to breach of the station hull by space debris, meteoroids, seal failure, or vent failure; chemical toxicity; and a large fire. The objectives of the current study are to identify the tasks required to be performed in emergencies, establish the time required to perform these tasks, and to review the human equipment interface in emergencies. It was found that a fixed time value specified for egress has shifted focus from the basic requirements of safe egress, that in some situations the crew members may not be able to complete the emergency egress tasks in three minutes without sacrificing more than half of the station, and that increased focus should be given to human factors aspects of space station design

Emergency egress requirements for Space Station Freedom

An objective was to determine if the pressurized elements and hatchways of the Space Station Freedom support the emergency egress of crewmembers during operation of the station at the stage of Permanently Manned Capacity. Emergency egress was defined as the exit from a pressurized element when an event occurs which makes that element uninhabitable. The possible egress paths for four emergency scenarios considered were: (1) accident occurs in a module and crewmembers translate to the attached node; (2) accident occurs at a node and crewmembers translate through it to the safe node; (3) accident occurs at a module close to a node and crewmembers are not able to translate through the affected area; and (4) accident occurs at a node and crewmembers cannot translate through it. The structural design of the pressurized elements and the hatches studied is adequate for the emergence egress translation requirement. The current location of a few racks may cause some obstruction for egress to the orbiter. The egress time required in the worst situation is estimated to be about 3 mins. There is a chance of getting crewmembers trapped in a module in case of a severe accident. Aids are needed for emergency egress translation

Farthest point problem and M-compact sets

In this paper we give an elementary proof of the fact that every uniquely remotal set is singleton in a finite dimensional strictly convex normed linear space. We show that if A is a uniquely remotal M-compact subset with the derived set of A non-empty then the derived set of A is M-compact and uniquely remotal. We also show that if A is a uniquely remotal M-compact set and the derived set of A is compact then A is singleton

Chebyshev centers that are not farthest points

In this paper we address the question whether in a given Banach space, a Chebyshev center of a nonempty bounded subset can be a farthest point of the set. Our exploration reveals that the answer depends on the convexity properties of the Banach space. We obtain a characterization of two-dimensional real strictly convex spaces in terms of Chebyshev center not contributing to the set of farthest points. We explore the scenario in uniformly convex Banach spaces and further study the roles played by centerability and M-compactness in the scheme of things to obtain a step by step characterization of strictly convex Banach spaces. We also illustrate with examples the optimality of our results

Decoration of titania nanofibres with anatase nanoparticles as efficient photocatalysts for decomposing pesticides and phenols

Using a series of partial phase transitions, an effective photocatalyst with fibril morphology was prepared. The catalytic activities of these materials were tested against phenol and herbicide in water. Both H-titanate and TiO2-(B) fibres decorated with anatase nanocrystals were studied. It was found that anatase coated TiO2-(B) fibres prepared by a 45 h hydrothermal treatment followed by calcination were not only superior photocatalysts but could also be readily separated from the slurry after photocatalytic reactions due to its fibril morphology

Moduli and BPS configurations of the BLG theory

We study the moduli space of scalars in the BLG theory with and without a constant background four-form field. The classical vacuum moduli space is sixteen-dimensional in the absence of the four-form field. In its presence, however, the moduli space of BPS configurations may be reduced in dimension. We exemplify this with a BPS configuration having $SO(1,2)$ world-volume symmetry and $SO(4) \times SO(4)$ R-symmetry in the presence of a four-form field, by constructing an explicit solution.Comment: 11 pages, LaTeX. References added. Zero mode of the gauge field is shown to furnish the 16th dimension of the moduli space. Some discussions improved. Version to appear in Physics Letters