Abstract: A fiber grating pressure sensor for use in an industrial process includes an optical sensing element 20,600 which includes an optical fiber 10 having a Bragg grating 12 impressed therein which is encased within and fused to at least a portion of a glass capillary tube 20 and/or a large diameter waveguide grating 600 having a core and a wide cladding and which has an outer transverse dimension of at least 0.3 mm. Light 14 is incident on the grating 12 and light 16 is reflected from the grating 12 at a reflection wavelength &lgr;1. The sensing element 20,600 may be used by itself as a sensor or located within a housing 48,60,90,270,300. When external pressure P increases, the grating 12 is compressed and the reflection wavelength &lgr;1 changes. The shape of the sensing element 20,600 may have other geometries, e.g., a “dogbone” shape, so as to enhance the sensitivity of shift in &lgr;1 due to applied external pressure and may be fused to an outer shell 50.

Abstract: A pressure-isolated Bragg grating temperature sensor includes an optical element which includes an optical fiber having at least one Bragg grating disposed therein. The Bragg grating is encased within and fused to at least a portion of an inner glass capillary tube, or comprises a large diameter waveguide grating having a core and a wide cladding and having the grating disposed therein, encased within an outer tube to form a chamber. An extended portion of the sensing element that has the grating therein extends inwardly into the chamber which allows the grating to sense temperature changes but isolates the grating from external pressure. More than one grating or pair of gratings may be used and more than one fiber or optical core may be used. At least a portion of the sensing element may be doped between a pair of gratings to form a temperature tuned laser, or the grating or gratings may be configured as a tunable DFB laser disposed in the sensing element.

Abstract: A fiber grating pressure sensor includes an optical sensing element 20, 600 which includes an optical fiber 10 having a Bragg grating 12 impressed therein which is encased within and fused to at least a portion of a glass capillary tube 20 and/or a large diameter waveguide grating 600 having a core and a wide cladding and which has an outer transverse dimension of at least 0.3 mm. Light 14 is incident on the grating 12 and light 16 is reflected from the grating 12 at a reflection wavelength &lgr;1. The sensing element 20, 600 may be used by itself as a sensor or located within a housing 48, 60, 90, 270, 300. When external pressure P increases, the grating 12 is compressed and the reflection wavelength &lgr;1 changes. The shape of the sensing element 20, 600 may have other geometries, e.g., a “dogbone” shape, so as to enhance the sensitivity of shift in &lgr;1 due to applied external pressure and may be fused to an outer shell 50.

Abstract: A method and apparatus for forming a tube-encased fiber grating includes an optical fiber 28 which is encased within and fused to at least a portion of a glass capillary tube 120 and a substantially transparent index-matching medium 122, such as an optically flat window, having an optically flat surface 126 adjacent to the tube 120. A substantially transparent index-matching intermediate material (e.g., UV transparent oil) 124 is used between the window 22 and the tube 120 to substantially eliminate the interface between the tube 120 and the medium 122. A pair of writing beams 26,34 are incident on and pass through the medium 122, the tube 120 and intersect and interfere in a region 30 on the fiber 28. Also, the width Wb of the writing beams 26,34 may be set to be less than the width Woil of the intermediate material 124 to eliminate surface damage (ablations) of the tube 120. Attentively, the medium 122 may have a geometry to eliminate surface ablations (e.g.

Abstract: A catalyst suitable for the catalysis of the oxidation of carbon monoxide is prepared by providing the substrate with tin (IV) oxide support material and with a catalytically active material.The tin (IV) oxide is provided by contacting the substrate with a dispersion of colloidal or non-colloidal particles in a liquid medium, said dispersion being convertible to tin (IV) oxide by drying and firing, followed by drying and firing. A catalyst can be so-produced having low flow resistance, high low temperature activity and relative insensitivity to deactivation by moisture. The dispersion may, for example, be a tin (IV) oxide aqua-sol made, for example, by peptising hydrated stannic oxide with a quaternary ammonium hydroxide.

Abstract: A supported catalyst is made by preparing a dispersion, contacting the dispersion with a substrate to produce a coating thereon, and firing and, if necessary, reducing to convert the dispersion to a catalytically active coating on the substrate. The catalyst may be useful in the catalysis of reactions for producing methane.The dispersion is made by co-hydrolysis to give an intimate mixture of hydrolysis products (e.g. hydroxides of Ni and Al) convertible by calcining and, if necessary, reduction to produce the catalytically active coating in the form of one or more catalytically active components (e.g. Ni) and one or more ceramic oxides (e.g. Al.sub.2 O.sub.3). Preferably, co-hydrolysis if effected by an agent such as urea which gives rise to no by-products in the coating.

Abstract: A device and method for use in the catalysis of a chemical reaction having a container with a fluid inlet thereto and a fluid outlet therefrom and a plurality of catalyst bodies assembled therein.In order to enhance the mixing of reactants in the device, the catalyst bodies are randomly arranged in the container and in order to reduce resistance to flow of reactants through the device, the catalyst bodies each have a plurality of internal channels of an ordered, pre-determined size and arrangement for permitting substantially unrestricted flow of reactants therethrough.