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: Reducing NO.sub.x emission levels from a gas turbine combustor having a premixer section by mixing a small portion of air into the fuel prior to injection into the premixer section. The portion of diverted air is approximately five percent of the total amount of air injected into the premixer section or such that the resulting fuel-air mixture in the fuel line is approximately half fuel and half air. The injection of air into the fuel line, referred to as "head start partial premixing," is effective to reduce the fluctuations and nonuniformities in the fuel concentration levels which increase NO.sub.x output.

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 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: 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 refrigerator apparatus is provided having a cabinet with a freezer compartment and a fresh food compartment. The compartments define two passageways allowing air circulation therebetween. A refrigerator system is included having a compressor, a condenser, an expansion valve, an evaporator situated in the freezer compartment. The refrigerator system elements are connected in series in a closed loop, in a refrigerant flow relationship. A first fan is situated in the freezer compartment for providing air flow over the evaporator. A second fan is situated in one of the two passageways for providing air circulation between the two compartments. A first thermostatic controller situated in the freezer compartment for maintaining a desired temperature in the freezer compartment by causing the compressor and the first fan to operate.

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.

Abstract: A multilayered insulated mold structure is provided. An insulation layer provided on each of the mold cores retains heat at the molding surface, thereby increasing surface quality of the finished part. The insulating layer has a varying density across its thickness so as to have a low density center region and high density surface regions. By having a relatively low denisty, the center region of the insulating layer has a low thermal conductivity. Thus, the insulating layer may be made from the same material as the core and still have an acceptable insulating value. The use of the same material for adjacent layers reduces the potential of delamination of the layers. The multilayered mold is compatible with passive or active heating of the molding surface.

Abstract: The detection of sound emitted from a source in a dynamic environment of ambient background noise employs a sufficiently distributed array of sound intensity probes enclosing a sound source is adapted to collect measurements over the same time interval in a non-specific acoustic environment. Each probe in the array is comprised of a pair of mutually spaced microphones generally unmatched in their gain and phase response. A multi-channel fourier spectrum analyzer is used to provide a direct signal processing determination of sound intensity at each probe from pressure measurements taken at each microphone. Their computation is corrected to compensate for gain and phase mismatch between each microphone pair using independently derived probe calibration factors. These correction factors are linearly applied to the sound intensity determination at each probe of the array.

Abstract: The present invention, utilizing recombinant DNA technology, provides a novel method for obtaining 20-deoxotylosin from a tylosin producing microorganism. 20-deoxotylosin is useful as an antibiotic with a microbial inhibitory activity similar to tylosin.

Abstract: A heat transfer arrangement for a refrigeration circuit is described. In one embodiment and for a refrigeration circuit including compressor means, a plurality of evaporator means coupled to the compressor means, one of the evaporator means being arranged to operate at a temperature lower than the operating temperature of the other evaporator means, the present heat transfer arrangement comprises a first conduit means coupled to the outlet of the one evaporator means, the first conduit means being at least partially disposed in a heat transfer arrangement with at least a portion of a second conduit means coupled to the inlet of the one evaporator means.

Abstract: A refrigerator apparatus is provided having a cabinet with a freezer compartment and a fresh food compartment. The compartments define two passageways allowing air circulation therebetween. A refrigerator system is included having a compressor, a condenser, an expansion valve, an evaporator situated in the freezer compartment. The refrigerator system elements are connected in series in a closed loop, in a refrigerant flow relationship. A first fan is situated in the freezer compartment for providing air flow over the evaporator. A second fan is situated in one of the two passageways for providing air circulation between the two compartments. A first thermostatic controlller situated in the freezer compartment for maintaining a desired temperature in the freezer compartment by causing the compressor and the first fan to operate.