Abstract: A rotary magnetic valve including a cylindrical housing having flow passages in both ends and a magnetically-responsive valve closure assembly rotatively mounted therein. The valve closure assembly includes an armature mounted to rotate about the longitudinal axis of the housing and a shoe slideably disposed on each end of the armature. Each shoe is biased away from the armature and into contact with the inner end surfaces of the housing. A controller assembly is provided to rotate the valve closure assembly between a first position where flow through the valve is prevented and a second position where flow is permitted. The controller includes at least one permanent magnet for biasing the valve closure assembly into one of the positions and an electromagnet for rotating the valve closure assembly into the other position. A three-way valve is also possible.

Abstract: A method and apparatus for converting computed tomography (CT) data into finite element models. The system generates both 2-D and 3-D models using the automatic mesh generators, QUADTREE and OCTREE, which are founded on recursive spatial decomposition. Multiple slices of CT data are obtained by scanning the object to be modeled. The slices are stacked and processed to form a discrete solid model. The discrete solid model is an alternate geometry defined discretely rather than with continuous analytic curves and surfaces but still provides a foundation for automatic mesh generation. Since the QUADTREE and OCTREE automatic mesh generators map naturally to the discrete solid model, the integration of CT technology and automatic mesh generation can be achieved.

Abstract: An open magnet having a frustoconical shaped inner bore is provided for MR imaging. The magnet has a plurality of axisymmetric superconducting coils of differing diameters which are disposed along an axis in order of successively increasing diameters so as to define the frustoconical shape. This shape permits a patient access opening which is much larger than that in conventional cylindrical magnets. The overall length is much less than the length of conventional systems. The combination of wide opening and short length facilitates patient access and presents a feeling of openness. Furthermore, the device can be tilted with respect to horizontal to increase the openness.

Abstract: Low refrigerant charge in a refrigeration system is detected by monitoring the oscillation of the thermal expansion valve. This monitoring is accomplished with a sensor which senses the oscillation of the expansion valve and produces a signal indicative of the valve oscillation. The sensor signal is fed to a monitoring controller which produces a low charge signal whenever the amplitude of valve oscillation falls below a predetermined level, thus indicating low charge conditions. The sensor is preferably a temperature sensor situated at either the outlet or the inlet of the evaporator. The system further comprises a validity evaluation controller for determining when valve oscillation is a valid indication of low charge. The validity evaluation controller analyzes a number of system operating characteristics which affect valve oscillation.

Abstract: A Si--SiC ceramic layer is bonded to a non-porous SiC substrate with the Si etched from the layer to form a relatively porous surface on the otherwise non-porous high strength SiC substrate. A quartz layer is softened by heating and forced into the pores of the porous layer to form a mechanical bond to the SiC substrate. A refractory metal layer is bonded to the quartz layer to complete the joint. A refractory metal support component is then bonded to the refractory layer whereby the quartz serves as a high strength, high temperature reaction barrier between the metal of the refractory layer and the silicon of the SiC substrate.

Abstract: A method and apparatus for thermoforming 3-dimensional articles of chosen wall thickness dimensions from a polar polymer sheet. The polymer sheet is dielectrically heated, the heating being controlled to impress a predetermined thermal pattern on the sheet. The thermal pattern is selected in accordance with the amount of stretching to which each area of the sheet is subjected during the subsequent work-forming step, the areas subjected to greater stretching being heated to a lower temperature and vice versa. Thus, the stretching action is balanced and results in accurate control of the wall thickness of the final article.

Abstract: Low charge detection for a refrigeration system is accomplished using a differential pressure sensor which detects superheat at the evaporator exit. The differential pressure sensor includes a casing having a reference chamber containing a reference charge of refrigerant. A pressure responsive snap member is disposed in the casing so as to have one side exposed to the reference chamber and another side exposed to the exit pressure of the evaporator. The snap member is normally biased into a first position but snaps to a second position when the pressure differential across it exceeds a predetermined level. When a low charge condition exits, the evaporator exit will exhibit superheat. Heat conduction through the casing raises the temperature, and thus the pressure in the reference chamber. Thus the pressure differential which causes the snap member to snap to the second position is created.

Abstract: An expanded fiber composite structure and process for making an expanded fiber composite structure are provided. The expanded fiber composite structure is made up of a fiber mat held in partial compression by a monolithic plastic coating on the fibers, the structure having a plurality of interstitial voids which may optionally be filled with a polymeric interstitial material. The process includes impregnating a fiber mat with a plastic material, compressing the mat to impregnate the mat with the plastic, fully wetting each fiber and creating a substantially void-free fiber/plastic matrix, and reducing the compressive forces on the mat, allowing the fibers to rebound and expand the mat to a predetermined desired thickness, in the process creating the interstitial voids. The structure is then cooled such that the plastic material stiffens and itself retains the structure at the desired thickness.

Abstract: X-ray tube noise is reduced by coupling the stator mass to the neck section of the glass vacuum tube so that vibrations are dissipated by the stator and not transmitted to the bulk of the vacuum tube. The coupling is accomplished with a non-magnetic sealing material such as an epoxy sealant. The sealant will generally fill the gap between the stator and the neck section of the vacuum tube. Alternatively, the coupling can be done with a mechanical clamping device.

Abstract: A supersonic combustion ramjet having a supersonic combustor. The supersonic combustor has a backward-facing step formed in a wall thereof and a forward-facing ramp formed in the wall downstream from the step. Hydrogen fuel is injected into the air flow by axially-directed fuel injectors disposed in the step and/or normally-directed fuel injectors disposed in the ramp. The ramp is inclined toward the center of the combustor so that fuel from the fuel injectors is turned into the main flow. The ensures rapid mixing which enables combustion to be completed within a distance on the order of one foot.

Abstract: Noise is reduced in an X-ray tube by inserting a non-glass insert between sections of the glass vacuum tube. The non-glass insert has an impedance which is significantly different than the impedance of the glass tube sections. This impedance mismatch inhibits vibration energy from passing from one glass section to the other. In addition to having a different impedance than the glass sections, the non-glass insert can be made of a heavier material, thus presenting sufficient mass to dissipate vibration energy. The non-glass insert is connected to the glass sections by a pair of connecting members, each of which has a coefficient of thermal expansion closely matching that of the glass sections. Each connecting member has a ring with an annular flange extending perpendicularly therefrom. The ring of each connecting member is attached a respective one of the glass sections and each flange is attached to the insert.

Abstract: A method for making a three-piece hollow airfoil includes preforming three metal sheets into initial shapes and sealing them together to form an in-process assembly. Internal cavities are formed in the assembly prior to sealing. The assembly is subjected to high temperature and pressure to diffusion bond the sheets together at selected points. The cavities are then subjected to internal pressure at high temperature in order to inflate and superplastically deform the assembly to the desired shape. Excess material may be machined off after inflation.

Abstract: Low refrigerant charge is detected in a refrigeration system under thermal expansion valve control with a valve stem stroke measurement switch. The switch includes a first contact mounted on the valve stem of the thermal expansion valve and a second contact mounted on the valve casing. The two contacts are aligned in the direction of valve stem motion and are relatively positioned so as to be normally closed but to open when the valve stem reaches its full stroke position. At least one of the contacts is mounted to its respective structure by a flexible member to accommodate the motion of the valve stem. The switch is connected to the compressor clutch to deactivate the compressor when opened. A timer can be provided to delay deactivation of the compressor in instances where the valve stem is just momentarily at full stroke.

Abstract: A refrigerant flow control unit for a refrigeration system, particularly a refrigeration system having a compressor, a condenser connected to receive refrigerant discharged from the compressor, and a plurality of evaporators. A first one of the evaporators is connected to receive at least a portion of the refrigerant discharged from the condenser and the remaining evaporators are connected to receive at least a portion of the refrigerant discharged from another evaporator. The refrigerant flow control unit is connected to receive at least a portion of the refrigerant discharged from each one of the evaporators. The refrigerant flow control unit is also connected to the compressor and is repeatedly operable to alternately connect one of the evaporators respectively in exclusive refrigerant flow relationship with the compressor.

Abstract: Apparatus for selectively regenerating at least one portion of an adsorbent bed in an adsorption system with a movable microwave device while the remainder of the bed is still being used. The adsorbent bed is held by a frame which divides the bed into a plurality of sections, each section holding a portion of the adsorbent. At least one movable regeneration carriage assembly which moves from section to section is provided. The carriage assembly supports a microwave heating device which heats the adsorbent in the section adjacent to the carriage assembly. Each section can be isolated from the others in turn and be regenerated while the remaining sections continue the adsorption function. The isolated section is swept by a purge gas which is conveyed to and from the section by flexible cords connected to the carriage assembly.

Abstract: An dynamoelectric machine is provided having a hollow shaft adapted to receive fluid at one end and to discharge it at the other. The hollow shaft has a stack of laminations mounted thereon. A hollow disk is situated adjacent to and in contact with an axial end of the stack of laminations. The hollow disk includes a generally circular baffle for dividing the hollow disk into two interior sections and to cause the fluid to rotate at the same angular velocity as the hollow disk. The two interior sections are in flow communication with one another of the periphery at the generally circular baffle. The hollow shaft is in flow communication with one of the sections for providing fluid and in flow communication with the other section for removing fluid. A stator surrounds the laminations and is spaced away therefrom.

Abstract: A system for reducing noise created by multiple rotating machines by synchronizing the machines so as to establish a phase relationship between the machines which minimizes the noise. One or more feedback sensors, such as microphones, are placed so as to sense the noise to be reduced. The noise signals from the microphones are sent to a controller. Tachometer signals of the rotational speed of each machine are also sent to the controller. The controller generates an output signal in response to the inputs from the microphones and the tachometers that is fed to one or more of the rotating machines in order to establish the desired phase relationships.

Abstract: A Si--SiC ceramic layer is bonded to a non-porous SiC substrate with the Si etched from the layer to form a relatively porous surface on the otherwise non-porous high strength SiC substrate. A quartz layer is softened by heating and forced into the pores of the porous layer to form a mechanical bond to the SiC substrate. A refractory metal layer is bonded to the quartz layer to complete the joint. A refractory metal support component is then bonded to the refractory layer whereby the quartz serves as a high strength, high temperature reaction barrier between the metal of the refractory layer and the silicon of the SiC substrate.

Abstract: A process for impregnating a glass fiber mat with a resin, and for producing composite structures having impregnated glass fibers, is provided which substantially reduces the number of voids in the resulting structure, provides fast and efficient heating of the materials, and requires low capital cost equipment to perform the process. The process includes heating a glass fiber mat and an RF-sensitive resin in a radio frequency electromagntic field to quickly heat the mat and resin, the resin flowing into voids in the glass fiber mat, thereby impregnating the mat; forming the resulting composite structure into a desired end shape; and cooling the structure. Reduction in the number of voids is advantageously accomplished by impregnating the resin into the mat under vacuum, which removes air and decomposition products which result from the RF heating of the resin.

Abstract: A method for reducing the NO.sub.x produced by the engine of a supersonic aircraft. A reducing agent is injected into the combustor or the exhaust region of the engine. The reducing agent can be either hydrogen azide or hydrazine in an aqeuous form. For injection into the combustor, injection will be perpendicular to the main air flow through the engine and into a downstream portion of the combustor. Injection is carried out whenever NO.sub.x reduction is needed. By injecting the reducing agent into the downstream portion of the combustor or into the exhaust region, the reduction reaction is decoupled from the combustion process so that engine performance is not impaired.