Abstract: The present invention relates to a refractory shield for protecting a superheater tube against fluid attack comprising first and second partial-tubes (2, 8), each partial-tube having a C-shaped cross section, the C-shaped cross section defining first (3, 9) and second (4, 10) ends; wherein the ends of the partial-tubes are opposably engaged, and wherein the partial-tubes comprise means (5) for preventing radial movement of the first partial-tube relative to the second partial-tube.

Abstract: This invention relates to an acetabular cup having a substantially hemispherical ceramic concave surface comprising at least one debris reservoir thereon having a width of between 0.010 mm and 2 mm, and also to a ceramic hip joint prosthesis head whose outer surface comprises a similar debris reservoir.

Abstract: A method of producing aluminum, comprising the steps of:a) providing an aluminum reduction Hall cell for reduction of alumina in molten fluoride electrolyte containing cryolite, the cell comprising a cathode, an anode and a sidewall, the sidewall having a thickness and comprising:i) a lining consisting essentially of a material selected from the group consisting of silicon nitride, silicon carbide, and boron carbide, and having a density of at least 95% of theoretical density, and no apparent porosity, andii) an insulating layer backing the lining,b) contacting the lining with an electrolyte comprising at least 60% cryolite and having a temperature of between 650.degree. C. and 1100.degree. C.

Abstract: A scintillation crystal module having an epoxy seal which has a coefficient of thermal expansion which is substantially the same as the backcap of the gamma camera. Among the suitable epoxy systems, the CTE of the epoxy could be modified somewhat by choosing a different catalyst or by adjusting the resin:catalyst ratio. The presently preferred epoxy system is a STYCAST.RTM. 2850 FT system available from W. R. Grace & Co. Using "catalyst 9" or "catalyst 11" from that system, a CTE of approximately 17.33.times.10.sup.-6 to approximately 19.4.times.10.sup.-6 in/in.degree. F. can be easily achieved. It has been discovered through analysis using FEA that an epoxy with a CTE in the range of 9.0 to 20.0.times.10.sup.-6 in/in.degree. F. provides satisfactory results in preventing seal separation during .+-.40.degree. F. temperature cycles.

Abstract: A scintillation detector (10) includes a scintillation crystal (14) and a shock absorbing member (76) circumscribing the crystal (14). A sleeve (98) circumscribes the shock absorbing member (76) which, in turn, is circumscribed by a housing (12). The sleeve (98) provides for substantial controlled radial loading on the crystal (14). A method of manufacturing the detector (10) includes placing the crystal (14) and shock absorbing member (76) into the sleeve (98), compressing the sleeve 98 and inserting the compressed sleeve (98) into the housing (12) such that the sleeve (98) substantially maintains its compression. The radial stiffness causes vibration induced counts to occur at an excitation frequency which is above the operational bandwidth of the radiation measurements, thereby excluding vibration induced counts for radiation measurements.

Abstract: This invention relates to hot pressed silicon carbide dummy wafers having low iron impurity levels, and a method of using hot pressed silicon carbide dummy wafers in silicon wafer processing applications.

Abstract: A well logging instrument and method that remove vibration induced noise from the output of a detector including a scintillation crystal. The invention is based on a realization that pulses induced by vibration during MWD operations are characteristically periodic, whereas pulses generated down hole by gamma rays occur at random intervals and are characteristically non-periodic. The instrument and method involve positioning a scintillation crystal package in the high vibration environment for interaction with incident radiation, using a light sensing device to convert photons received from the scintillation crystal package into an electrical signal which over time is composed of radiation induced events that are non-periodic and vibration induced events that are periodic, distinguishing the periodic events using a time history of the electrical signal, and removing the periodic events from the electrical signal to provide a corrected electrical signal from which vibration induced components have been removed.