Abstract: A modular radiation detector includes a scintillator module containing a crystal, and an electronics module containing a light sensing device such as a photomultiplier tube (PMT), and an electronics package. The scintillator module and the electronics module are releaseably mechanically coupled, for example by means of mating threaded portions on each of the modules. The crystal and the PMT are optically coupled via an optical window in the scintillator module and a removable gel pad which is pressed between the modules as they are mechanically coupled together.

Abstract: A pump diaphragm includes a layer fabricated from polytetrafluoroethylene (PTFE) and an integral stud. In one embodiment, the stud is encapsulated within a hub assembly fabricated from PTFE and fastened to the PTFE layer with adhesive or welding, etc. In alternate embodiments, the stud may be molded in-situ with the PTFE layer using various methodology, including pressing the stud onto a heated PTFE layer. The PTFE layer then may be subjected to various forming operations to provide the diaphragm with desired dimensions and/or properties. Moreover, an additional layer or layers, such as an elastomeric layer, may be laminated onto an inside surface of the PTFE layer to provide a composite pump diaphragm.

Abstract: Apparatus and method for electronically screening abnormal glow curves of thermoluminescenct materials such as LiF:Mg,Ti in routine dosimetry, wherein glow curves with abnormal patterns are identified by examining a few key features from which information about background and thermoluminescent (TL) signals can be extracted. By analyzing the records of quality control (QC) cards that are in the same group as field cards, dosimeter- and reader-dictated parameters, such as the peak location, are automatically determined, thus eliminating the need for any prior knowledge of those conditions required for reference determination. The apparatus and method are applicable to dose levels down to at least 50 .mu.Sv.

Abstract: A composite ceramic structure which does not fail catastrophically and thus is useful as a ceramic rolling contact bearing assembly is disclosed. The structure is a ceramic monolith bonded through an interlayer to a fiber-reinforced ceramic body. The structure is useful at elevated temperatures.

Abstract: Finely divided silicon carbide materials, particularly powders, whiskers and short fibers, are provided with a titanium nitride surface coating by the process of (i) placing a low carbon diffusivity layer atop the silicon carbon, (ii) placing a titanium metal coating atop the low carbon diffusivity layer, and (iii) nitriding the titanium metal.

Abstract: An electric furnace comprising a container having electrically isolated wall segments useful for melting materials, particlularly ceramics, is disclosed.The electric fornace's side walls are constructed from electrically isolated segments, which cause electric current from a plasma torch to be concentrated on the material in the furnace to be melted rather than diverted to the walls of the furnace.

Abstract: Solids that are subject to a deleterious reaction with a dispersion medium in which they are suspended can be safely comminuted in that dispersion medium by providing therein a surfactant capable of reacting with the solid at a faster rate than the dispersion medium can so react to thereby suppress the deleterious reaction. In particular, unsintered silicon nitride or silicon carbide which when contacted with water would decompose to form silica on their surfaces can be milled in water, without producing excessive amounts of silica. The dispersions produced are sufficiently stable to be filtered through openings of 2 microns with loss of no more than 5% of the silicon nitride or carbide. Stable dispersions of solids in liquids can be coated with a different solid by surface precipitation under conditions which preclude the formation of a bulk precipitate.

Abstract: A process for improving the strength of a sialon powder formed by a spray drying process is disclosed. The process involves the addition of small amounts of a hydrophilic silane to the slurry of inorganic powders and water which is fed to the spray dryer.

Abstract: A novel process for rapid solidification of ceramic melts combines certain features of cooling by atomization and by contact with chilling surfaces. The material to be solidified is divided into fine liquid droplets that are propelled by a rapid flow of gas toward a rapidly moving chill surface, striking the surface with sufficient velocity to flatten each drop into a flat flake like shape. Apparatus for the process is also disclosed. The process is particularly applicable to making very fine grained, or even amorphous, ceramic materials that can be powdered and then sintered into strong, tough ceramic structures.

Abstract: A friable silicon nitride body is prepared by infiltrating a non-friable silicon nitride body with a fluid which expands upon freezing, rapidly freezing the fluid, and thawing the frozen fluid. Silicon nitride flakes and chunks obtained with only light pressure on the friable body may then be final milled to a desired particle size more rapidly and with less energy input than with conventionally processed silicon nitride. The silicon nitride body may have a higher density than has previously been used to prepare silicon nitride powders, thereby preventing the generation of potentially hazardous whiskers in the final powder product.

Abstract: An improved process of preparing silicon nitride by the direct nitridation of silicon metal is disclosed. The process is a multi-step one which is substantially more efficient than prior processes and produces a silicon nitride having an oxygen content of less than 1%, a silicon metal content of less than 0.5%, and an alpha phase content of at least 85%, preferably at least 90%. The silicon nitride may be converted to a powder.