Abstract: A test apparatus for evaluating thermal properties of a test specimen across a wide range of thermal conductivities and temperature ranges using a flat plate cup cryostat. The test apparatus includes: a heater assembly having an upper surface to receive a test specimen; a cold plate positioned on top of the test specimen; a vessel comprising an outer cylindrical tube closed on a bottom end by the cold plate; an inner cylindrical tube concentrically received in an upper portion of the outer cylindrical tube above the vessel to vent the vessel; insulation material surrounding at least the heater assembly, test specimen, cold plate, and vessel; a sensor that detects boiloff or evaporation rate of liquid from the vessel vented from the inner cylindrical tube; temperature sensors positioned to detect temperatures of the heater assembly and the cold plate; and a data recording device to record the boiloff or evaporation rates and temperature values.

Abstract: A test apparatus for thermal energy measurement of disk-shaped test specimens has a cold mass assembly locatable within a sealable chamber with a guard vessel having a guard chamber to receive a liquid fluid and a bottom surface to contact a cold side of a test specimen, and a test vessel having a test chamber to receive a liquid fluid and encompassed on one side by a center portion of the bottom surface shared with the guard vessel. A lateral wall assembly of the test vessel is closed by a vessel top, the lateral wall assembly comprising an outer wall and an inner wall having opposing surfaces that define a thermal break including a condensable vapor pocket to inhibit heat transfer through the lateral wall from the guard vessel to the test vessel. A warm boundary temperature surface is in thermal communication with a lower surface of the test specimen.

Abstract: A pressure relief valve includes a housing having a fluid inlet and at least one fluid outlet. A first structure mounted in the housing and fixed in relation thereto is in magnetic attraction with a second structure coupled to a piston disposed in a portion of the housing. The piston defines a chamber disposed adjacent to the fluid outlet(s) throughout the piston's stroke. The piston includes a sealing element providing a sealing force to prevent flow through the valve. The sealing force is independent of the magnetic attraction force between the first and second structures.

Abstract: A test apparatus for thermal energy measurement of disk-shaped test specimens has a cold mass assembly locatable within a sealable chamber with a guard vessel having a guard chamber to receive a liquid fluid and a bottom surface to contact a cold side of a test specimen, and a test vessel having a test chamber to receive a liquid fluid and encompassed on one side by a center portion of the bottom surface shared with the guard vessel. A lateral wall assembly of the test vessel is closed by a vessel top, the lateral wall assembly comprising an outer wall and an inner wall having opposing surfaces that define a thermal break including a condensable vapor pocket to inhibit heat transfer through the lateral wall from the guard vessel to the test vessel. A warm boundary temperature surface is in thermal communication with a lower surface of the test specimen.