Abstract: A compact method for forming strong hermetic bonds and seals. Such bonds are made simply and with no intervening adhesives, by directly melting a thermoplastic polymer against or between two surfaces of thermoset materials.

Abstract: A compact method for forming strong hermetic bonds and seals. Such bonds are made simply and with no intervening adhesives, by directly melting a thermoplastic polymer against or between two surfaces of thermoset materials.

Abstract: A compact, optically double-ended sensor probes with at least one 180° bend provided in the optical fiber in close proximity to a fiber Bragg grating temperature sensor suspends the optical fiber within a casing in such a way that the expansion and contract of the probe casing will not materially influence the temperature reading of the fiber Bragg grating by adding time varying or temperature varying stress components.

Abstract: A compact, optically double-ended sensor probe with at least one 180° bend provided in the optical fiber in close proximity to a fiber Bragg grating temperature sensor suspends the optical fiber within a casing in such a way that the expansion and contract of the probe casing will not materially influence the temperature reading of the fiber Bragg grating by adding time varying or temperature varying stress components.

Abstract: Optical fiber anchors accomplishing low creep confinement or fixing of a section of optical fiber in an assembly compact enough to be used conveniently as an anchor or as an enabling part of a strain or temperature sensor while retaining low optical losses and the original buffer coating to prevent the fiber from being exposed to abrasion and other influences that could lead to breakage. A rigid body is used that is mechanically stiff and hard enough to prevent the fiber from cutting into it or distorting the medium or substrate when subjected to stress, even over a long period of years. Trapping can be accomplished by molding the bent fiber into the substrate or body, adhesively bonding or soldering the optical fiber into a confining curved groove in a body or substrate.

Abstract: Sensors operate by resolving changes in orientation of a wavelength dependent structure with respect to a reference direction determined by an incident light beam, resulting in very high sensitivity and dynamic range. Said sensors are wavelength encoded, can be multiplexed in a single light path such as an optical fiber, yet are decoupled mechanically from the fiber, resulting in high stability.

Abstract: Optical fiber anchors accomplishing low creep confinement or fixing of a section of optical fiber in an assembly compact enough to be used conveniently as an anchor or as an enabling part of a strain or temperature sensor while retaining low optical losses and the original buffer coating to prevent the fiber from being exposed to abrasion and other influences that could lead to breakage. A rigid body is used that is mechanically stiff and hard enough to prevent the fiber from cutting into it or distorting the medium or substrate when subjected to stress, even over a long period of years. Trapping can be accomplished by molding the bent fiber into the substrate or body, adhesively bonding or soldering the optical fiber into a confining curved groove in a body or substrate.

Abstract: Optical fiber anchors accomplishing low creep confinement or fixing of a section of optical fiber in an assembly compact enough to be used conveniently as an anchor or as an enabling part of a strain or temperature sensor while retaining low optical losses and the original buffer coating to prevent the fiber from being exposed to abrasion and other influences that could lead to breakage. A rigid body is used that is mechanically stiff and hard enough to prevent the fiber from cutting into it or distorting the medium or substrate when subjected to stress, even over a long period of years. Trapping can be accomplished by molding the bent fiber into the substrate or body, adhesively bonding or soldering the optical fiber into a confining curved groove in a body or substrate.

Abstract: Optical fiber anchors accomplishing low creep confinement or fixing of a section of optical fiber in an assembly compact enough to be used conveniently as an anchor or as an enabling part of a strain or temperature sensor while retaining low optical losses and the original buffer coating to prevent the fiber from being exposed to abrasion and other influences that could lead to breakage. A rigid body is used that is mechanically stiff and hard enough to prevent said fiber from cutting into it or distorting said medium or substrate when subjected to stress, even over a long period of years. Trapping can be accomplished by molding the bent fiber into the substrate or body, adhesively bonding or soldering the optical fiber into a confining curved groove in a body or substrate.

Abstract: Sensors operate by resolving changes in orientation of a wavelength dependent structure with respect to a reference direction determined by an incident light beam, resulting in very high sensitivity and dynamic range. Said sensors are wavelength encoded, can be multiplexed in a single light path such as an optical fiber, yet are decoupled mechanically from the fiber, resulting in high stability.

Abstract: A compact, optically double-ended sensor probe with at least one 180° bend provided in the optical fiber in close proximity to a fiber Bragg grating temperature sensor suspends the optical fiber within a casing in such a way that the expansion and contract of the probe casing will not materially influence the temperature reading of the fiber Bragg grating by adding time varying or temperature varying stress components.

Abstract: A gas sensor includes an in-fiber resonant wavelength device provided in a fiber core at a first location. The fiber propagates a sensing light and a power light. A layer of a material is attached to the fiber at the first location. The material is able to absorb the gas at a temperature dependent gas absorption rate. The power light is used to heat the material and increases the gas absorption rate, thereby increasing sensor performance, especially at low temperatures. Further, a method is described of flash heating the gas sensor to absorb more of the gas, allowing the sensor to cool, thereby locking in the gas content of the sensor material, and taking the difference between the starting and ending resonant wavelengths as an indication of the concentration of the gas in the ambient atmosphere.

Abstract: A compact, optically double-ended sensor probes with at least one 180° bend provided in the optical fiber in close proximity to a fiber Bragg grating temperature sensor suspends the optical fiber within a casing in such a way that the expansion and contract of the probe casing will not materially influence the temperature reading of the fiber Bragg grating by adding time varying or temperature varying stress components.

Abstract: A gas sensor includes an in-fiber resonant wavelength device provided in a fiber core at a first location. The fiber propagates a sensing light and a power light. A layer of a material is attached to the fiber at the first location. The material is able to absorb the gas at a temperature dependent gas absorption rate. The power light is used to heat the material and increases the gas absorption rate, thereby increasing sensor performance, especially at low temperatures. Further, a method is described of flash heating the gas sensor to absorb more of the gas, allowing the sensor to cool, thereby locking in the gas content of the sensor material, and taking the difference between the starting and ending resonant wavelengths as an indication of the concentration of the gas in the ambient atmosphere.

Abstract: Film resistors, for example, thin film thermistors having a negative temperature coefficient (NTCR) or near-zero TCR electronics resistors, are formed of an alloy of both an electrically insulating oxide and an electrically conducting nitride of at least one metal selected from titanium, tantalum, zirconium, hafnium and niobium. The electrically insulating oxide of the at least one metal is preferably present in the film sufficient to impart a negative temperature coefficient of resistance to thermistors which include the film as a component part. Preferably, the metal is reactive with both an oxygen-containing gas and nitrogen and is deposited onto a substrate by reactive sputtering in the presence of an inert gas (e.g., argon). By controlling the volume ratio of the reactive gasses (e.g.

Abstract: Thin or thick film resistor devices (e.g., electronic resistors and thermistors) are trimmable without disturbing the active resistor film or necessarily requiring temperature control during trimming by providing a plurality of electrically conductive fingers having one end integral with one of the electrodes and a terminal end which extends at least substantially across the cross-wise dimension of the resistance film. The electrode fingers thereby electrically bridge a respective surface region of the substrate on which the electrodes and film are disposed. One or more of these fingers may thus be severed from the electrodes at the bridged respective surface region of the substrate so that the resistance value of the device can be controllably selected.

Abstract: A method is disclosed of controlling and improving the sensitivity of silicon PIN diodes to dosage by fast neutrons. The method includes selecting a silicon mass of high resistivity n or p-type material having a relatively long minority carrier lifetime, in excess of 250 microseconds ( .mu. sec) providing n.sup.+ and p.sup.+ -type junctions, and arranging the mass to obtain a silicon PIN diode dosimeter having a preselected ratio of edge area to volume. A silicon PIN diode personnel dosimeter sensitive to a radiation level of absorbed dose as low as 0.1 rad has been produced; this dosimeter, in the range from about 0.1 rad to about 10 rads has a sensitivity of at least 10 mV/rad.