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Utilization of the Surface Tension of Liquid Metals in Making High-Vacuum Seals

Description: Abstract: "The free energy (surface tension) of a liquid film can withstand atmospheric pressure across a maximum theoretical gap of 10-(-3) cm between solids if the liquid wets and bridges the sides of the gap continuously. The eutectic alloy of Ga, lm and Sm is used for this purpose. This alloy is molten at room temperature with surface tension > 500 dynes/cm, vapor pressure < 10-(-8) cm at 500 C and excellent wetting properties. This alloy can be utilized in valves, motion seals, flanged joints and for electrical contacts mounted in any position. Using ultrasonic soldering techniques without heat or flux this alloy is readily wetted on W, Mo, Ta, pyrex, quartz and certain ceramics. These materials will withstand the corrosive action of this alloy at at least 400 C. Some de-wetting has been observed with only the nonmetals at high temperatures. This de-wetting may be due to thermal decomposition of gallium oxide. Stainless steel is easily wetted, but is attacked at temperatures above 300 C. Copper and brass are attacked at room temperature."
Date: August 30, 1957
Creator: Milleron, Norman
Partner: UNT Libraries Government Documents Department

Base Realignment and Closure (BRAC): Property Transfer and Disposal

Description: The Defense Base Realignment and Closure Act of 1990 and the Federal Property and Administrative Services Act of 1949 provide the basic framework for the transfer and disposal of military installations closed during the base realignment and closure (BRAC) process. This report provides an overview of the various authorities available under the current law and describes the planning process for the redevelopment of BRAC properties.
Date: February 23, 2005
Creator: Flynn, Aaron M
Partner: UNT Libraries Government Documents Department

Fluidtight Seal for a Container

Description: A fluidtight seal for a container is formed by abutting a metal ring with a step machined in a convexo-concave container closure device and inserting this assembly into an open end of the container. Under compressive force, the closure device deforms causing the metal ring to pivot about the step on the closure device and interact with symmetrically tapered inner walls of the container to form a fluidtight seal between the container and the closure device. The compressive force is then withdrawn without affecting the fluidtight characteristic of the seal. A destructive force against the container closure device is necessary to destroy the fluidtight seal.
Date: March 31, 1999
Creator: Morrison, Edward F.
Partner: UNT Libraries Government Documents Department

Military Base Closures: Role and Costs of Environmental Cleanup

Description: This report provides an overview of cleanup requirements for the transfer and reuse of base closure properties, discusses the status of property transfer on bases closed under prior rounds, examines costs to clean up bases closed under these prior rounds, and discusses cleanup costs and issues for the 2005 round.
Date: November 15, 2005
Creator: Bearden, David M.
Partner: UNT Libraries Government Documents Department