Abstract: An active gas regenerative refrigerator includes a plurality of compressor-expander units, each having a hermetic cylinder with a drive piston configured to be driven reciprocally therein, and a quantity of working fluid in each end of the cylinder. A piston seal in a central portion of the cylinder prevents passage of the working fluid between ends of the cylinder. Movement of the piston to a first extreme results in radial compression of one of the quantities of working fluid in a cylindrical gap formed between one end of the piston and an inner surface of the cylinder, while the other quantity is expanded in the opposite end of the cylinder. The piston includes a plurality of magnets arranged in pairs, with magnets of each pair positioned with like-poles facing each other. A piston drive is configured to couple with transverse magnetic flux regions formed by the magnets.

Abstract: An active gas regenerative refrigerator includes a plurality of compressor-expander units, each having a hermetic cylinder with a drive piston configured to be driven reciprocally therein, and a quantity of working fluid in each end of the cylinder. A piston seal in a central portion of the cylinder prevents passage of the working fluid between ends of the cylinder. Movement of the piston to a first extreme results in radial compression of one of the quantities of working fluid in a cylindrical gap formed between one end of the piston and an inner surface of the cylinder, while the other quantity is expanded in the opposite end of the cylinder. The piston includes a plurality of magnets arranged in pairs, with magnets of each pair positioned with like-poles facing each other. A piston drive is configured to couple with transverse magnetic flux regions formed by the magnets.

Abstract: An active gas regenerative refrigerator includes a plurality of compressor-expander units, each having a hermetic cylinder with a drive piston configured to be driven reciprocally therein, and a quantity of working fluid in each end of the cylinder. A piston seal in a central portion of the cylinder prevents passage of the working fluid between ends of the cylinder. Movement of the piston to a first extreme results in radial compression of one of the quantities of working fluid in a cylindrical gap formed between one end of the piston and an inner surface of the cylinder, while the other quantity is expanded in the opposite end of the cylinder. The piston includes a plurality of magnets arranged in pairs, with magnets of each pair positioned with like-poles facing each other. A piston drive is configured to couple with transverse magnetic flux regions formed by the magnets.

Abstract: An active gas regenerative refrigerator includes a plurality of compressor-expander units, each having a hermetic cylinder with a drive piston configured to be driven reciprocally therein, and a quantity of working fluid in each end of the cylinder. A piston seal in a central portion of the cylinder prevents passage of the working fluid between ends of the cylinder. Movement of the piston to a first extreme results in radial compression of one of the quantities of working fluid in a cylindrical gap formed between one end of the piston and an inner surface of the cylinder, while the other quantity is expanded in the opposite end of the cylinder. The piston includes a plurality of magnets arranged in pairs, with magnets of each pair positioned with like-poles facing each other. A piston drive is configured to couple with transverse magnetic flux regions formed by the magnets.

Abstract: This invention relates to novel chemical compositions and manufacturing methods for producing electro-conductive, metal-ceramic materials having improved structural stability to operate at high temperatures in oxidizing atmospheres.

Abstract: This invention relates to novel chemical compositions and manufacturing methods for producing electro-conductive, metal-ceramic materials having improved structural stability to operate at high temperatures in oxidizing atmospheres.

Abstract: Flexible setter powder deposition sheets containing setter powders were developed for sintering of ceramic articles including tapes by an economical, fast and simple method. The sheets provide for deposition of a thin and uniform layer of setter powders on a green ceramic article after burnout of a binder in the sheet. Because of high strength and low burnout temperature, hydroxypropyl methylcellulose binder is preferred for production of these sheets. Tape cast sheets with low solids loading can be obtained by optimizing the wetting behavior of aqueous slurries on tape carrier. Setter, powder deposition sheets are of particular benefit in processing of thin ceramic tapes, particularly for processing of piezoelectric ceramic tapes. Tapes can be processed in a sandwich formed by layering setter powder deposition sheets between tapes and cover plates employed to maintain tape flatness and to reduce evaporation of volatile components of the ceramic.

Abstract: The present invention is a hydrocarbon fired thermophotovoltaic furnace having a non-fused silica tube. In a preferred embodiment, the furnace has an infrared emitter tube having a top end and a bottom end and a substantially transparent non-fused silica window tube having a closed top end. The window tube is positioned concentrically around the infrared emitter tube, and the infrared emitter tube is in fluid communication with the window tube. The window tube is preferably composed of Lucalox (alumina or Chromolux), magnesia, yterria, titania, spinel, stablized zirconia or yterria alumina garnet. In another preferred embodiment, the furnace has a radiator tube having a top end and a bottom end and an infrared emitter tube having a closed top end. The infrared emitter tube is positioned concentrically around the radiator tube, and the radiator tube is in fluid communication with the infrared emitter tube. Fluid flows from the inner tube to the outer tube.

Abstract: A three-layer solid infrared emitter having a spectral output matched to low bandgap TPV cells is provided. The three layers include inner and outer layers, and a core layer between the inner and outer layers. The core layer is of solid fiber reinforced undoped refractory oxide material. The inner layer of siC material absorbs radiation from the radiator, the core layer conducts heat from the inner layer to the outer layer. The core layer is a strengthening layer forming a diffuse reflector for stopping a shine-through of long wavelength radiation from the inner layer thereby preserving spectral selectivity in the outer layer. The emitter material may be cobalt doped, nickel doped, or combination of Ni or Co doped refractory oxides with erbia or a thin erbia selective emitter layer.

Abstract: A thermophotovoltaic generator apparatus includes a thermophotovoltaic converter assembly and a cooling fan positioned beneath the assembly for generating an updraft around the assembly. A fuel source is connected to the converter assembly by a fuel line. A new control system, which may include a non-metallic electrode for flame sensing and, regulates flow of fuel from the fuel source to the converter assembly. A housing encloses the cooling fan and the converter assembly. The converter assembly includes a fuel injector cup having a fuel inlet connected to the fuel source and a fuel outlet. A combustion chamber is positioned above the cup for receiving fuel from the fuel outlet and for allowing hydrocarbon combustion. A combustion fan is positioned between the cup and the cooling fan for generating an updraft into the combustion chamber. An infrared emitter is positioned around the combustion chamber for emitting infrared radiation when heated by combustion gases resulting from the hydrocarbon combustion.

Abstract: A thermophotovoltaic generator includes an infrared cobalt oxide doped refractory ceramic emitter having a broad power band region which is matched with the energy conversion band of a low bandgap thermophotovoltaic cell receiver. The generator is provided with a heat source or is constructed for mounting on a heat source or for holding a heat source, such as a radioisotope. The generator is compatible with any heat source, including, but not limited to, a hydrocarbon flame, nuclear reactors, and radioisotopes. The emitter is made of a refractory ceramic material such as cobalt oxide doped alumina or magnesia. The refractory compound of the emitter is preferably doped with a small number of substitutional ions to create a material for emitting near blackbody radiation in a wide wavelength band above a threshold energy level and a minimal amount of radiation at wavelengths longer than the threshold level.

Abstract: The tag includes an active strip of magnetic material that, when in the presence of a magnetic bias field within a predetermined magnetic field intensity range, responds to excitation by electromagnetic radiation of a first predetermined frequency by radiating electromagnetic radiation of a second predetermined frequency that is a frequency-divided quotient of the first predetermined frequency; and a pair of bias strips of magnetic material disposed in relation to the active strip in a common housing with the active strip for magnetically biasing the active strip with a magnetic bias field within the predetermined magnetic field intensity range. The bias strips are cut from an extruded magnetic material ribbon having a width less than the length of the active strip and a magnetic moment parallel to the lateral dimension of the ribbon.

Abstract: A magnetometer for detecting variations in a DC magnetic field. The magnetometer includes a magnetic field variation sensitive device that resonates at a characteristic resonant frequency by converting energy stored therein as a result of being excited by electromagnetic radiation at twice the resonant frequency when biased by a DC magnetic bias field within a predetermined field intensity range in which the amplitude of the resonance varies with variations of the field intensity.

Abstract: A batteryless, portable, transponder useful in a tag for a presence detection system. The transponder detects electromagnetic radiation at a first predetermined frequency and responds to said detection by transmitting electromagnetic radiation at a second frequency that is a subharmonic of the first frequency. The transponder includes an amorphous magnetic material component for storing energy from the electromagnetic radiation detected at the first frequency for transmission as the electromagnetic radiation transmitted at the second frequency.

Abstract: A batteryless, portable, frequency divider, consisting of a single resonant circuit including a nonlinear inductor having a core made of amorphous magnetic material; and a capacitance connected in series with the inductor to define a resonant circuit that detects electromagnetic radiation at a first predetermined frequency and responds to said detection by transmitting electromagnetic radiation at a second frequency that is a subharmonic of the first frequency. The resonant circuit may further include a second inductor connected in series with the nonlinear inductor and the capacitance to define the resonant circuit. The core of the nonlinear inductor includes an elongated thin flat ribbon of low coercivity amorphous magnetic material.