摘要:
A novel method for determining a coefficient of moisture expansion of a single, identified workpiece or coupon. The method includes the steps of positioning the workpiece in a chamber having known environmental parameters; determining a workpiece length change .DELTA.L caused by a chamber induced change in the workpiece moisture content .DELTA.M, by positioning first and second transformers to opposite ends of the single workpiece; and, measuring a chamber induced change in the workpiece moisture content .DELTA.M, by weighing the workpiece.
摘要:
An assembly for determining a coefficient of moisture expansion of a single, identified workpiece or coupon. The assembly includes means for positioning the workpiece in a chamber having known environmental parameters; means for determining a workpiece length change, .DELTA.L caused by a chamber induced change in the workpiece's moisture content .DELTA.M; and, means for measuring a chamber-induced change in the workpiece's moisture content .DELTA.M.
摘要翻译:用于确定单个识别的工件或试样的水分膨胀系数的组件。 组件包括用于将工件定位在具有已知环境参数的室中的装置; 用于确定工件长度变化的装置,由室引起的DELTA L引起工件的水分含量DELTA M的变化; 以及用于测量腔室引起的工件水分含量的变化的方法DELTA M.
摘要:
According to one aspect of this invention, a deployable shade assembly is provided. The deployable shade assembly comprises a plurality of pivotable panels arranged circumferentially about a common central axis. Each pivotable panel is configured to pivot about a hinge axis oriented in a plane substantially perpendicular to the common central axis. The deployable shade assembly further comprises a plurality of interleaved panels, whereby each interleaved panel is hingedly coupled between adjacent pivotable panels. The pivotable and interleaved panels form a closed structure in a collapsed state of the shade assembly, and the pivotable and interleaved panels form an opening in a deployed state of the shade assembly.
摘要:
Strut joint assemblies which include built-in off-loading capability or mirror support systems allow a user to minimize the friction developed at the ball joint interface. Each strut joint assembly includes an upper ball joint and a lower ball joint. Each of the ball joints is sealed such that an internal compartment is created which can act essentially as an air spring. By raising the air pressure within these compartments, the load on the ball joint is reduced until the joint separates and air pressure alone carries the entire load. By adjusting the pressure to a value just below the separation pressure, the ball can still maintain contact with the ball socket and carry very little of the actual load. At this pressure, the frictional moment that can be generated by the joint is minimized and is, thus, greatly reduced from the frictional moment developed by a joint which is carrying the full gravity load of the mirror. The entire strut assembly may be translated using an adjusting screw at the lower end of the strut. Once adjustment of the mirror position is complete, the joint may be locked by injecting an epoxy adhesive into the cavity between the strut shank shoulder and the potting cup of the mount pad and allowed to cure. After the epoxy is cured, air pressure may be released.
摘要:
A flexure structure for mounting an element such as a mirror in an optical device to a frame such as a telescope support structure includes a flexure blade defining a fork having three coplanar tines. A first mounting pad is located on the center tine for attaching the flexure blade to the mirror. A pair of mounting feet are located on the outside tines for attaching the flexure blade to the frame. The relative sizes of the tines being such that zero moment is applied to the mirror by the flexure structure when the mirror is displaced relative to the frame.
摘要:
An assembly and method suitable for determining the coefficient of thermal expansion (CTE) of a workpiece. The assembly includes a dual channel laser interferometer system placed in operative association with the workpiece, and a vacuum, heating and cooling chamber surrounding the workpiece. The assembly is particularly useful for determining the CTE of a workpiece having a relatively low value, e.g., a CTE less than 0.1.times.10.sup.-6 inch/inch .degree.F. It is therefore advantageously employed for determining the CTE of a workpiece comprising a composite, like a graphite/epoxy composite, that may have a CTE in the range of .+-.0.2.times.10.sup.-6 inch/inch .degree.F.
摘要:
An improved dilatometer suitable for testing the coefficient of thermal expansion (CTE) of a workpiece. The workpiece having a CTE in the range of -0.2.times.10.sup.-6 inch/inch .degree.F. to 0.2.times.10.sup.-6 inch/inch/.degree.F. The improvement includes a reference structure means for positioning and isolating the workpiece, and for maintaining an independent reference temperature, uninfluenced by a required workpiece temperature differential. The temperature independent reference structure means helps assure that measurements of expansions/contractions of the workpiece, as a function of temperature, are uniquely that of the workpiece, and not that of the reference structure means, or any other ambient temperature determinant. The improved dilatometer is particularly useful for determining the CTE of a workpiece having a relatively low value, e.g., a CTE less than 0.1.times.10.sup.-6 inch/inch .degree.F.