Abstract: An optical fiber having an intense polarization plane maintenability is constructed of an optical waveguide having a circular core and a circular cladding, a jacket formed on the outer circumference of the optical waveguide and having an elliptical outer circumference, and a supporting portion formed on the jacket.In order to fabricate the above-specified optical fiber, a preformed rod therefor is prepared by forming the inner wall of an silica glass tube with the jacket and the optical waveguide made of such materials as satisfy a relationship of c.sub.2 /a.gtoreq.200/(100-.gamma.)-1, wherein: letter .gamma. stands for the ellipticity of the outer circumference of the aforementioned jacket; letter c.sub.2 stands for the minor axis of an ellipse; and letter a stands for the radius of the circular optical waveguide, and by subsequently collapsing the aforementioned silica glass tube while having its internal pressure made lower than the atmospheric pressure by 1 to 20 mmH.sub.2 O.

Abstract: A method for enhancing hydrophobicity of high volatile bituminous coal and coals of a lower grade and for separating ash and sulfur (including pyritic sulfur) contaminants from coal in a floatation process. The method comprises the steps of grinding the coal to small particulate size, forming a slurry of the ground coal and mixing the slurry with at least one compound selected from the group comprising inorganic peroxy compounds, the preferred compound being oxone which is a mixture of potassium monopersulfate, potassium hydrogen sulfate and potassium sulfate. This slurry is allowed to react to condition the particulate coal and develop increased hydrophobicity for the coal while depressing the sulfur contaminants and ash during froth flotation.

Abstract: In a press for papermaking comprising in combination, a pair of elongated rollers arranged one to another to provide an adjustable elongated nip therebetween, each of the rollers comprising a substantially rigid elongated shaft and a substantially rigid elongated sleeve overlying and rotatably supported upon the elongated shaft, the respective shafts extending outboard of the respective sleeve to provide two pairs of parallel spaced shaft outboard portions, the improvement comprising, in the case of each roller, providing a circumferentially extending running fit between the outer surface of the shaft and the inner surface of the sleeve defining an elongated annular chamber extending lengthwise of the sleeve. Other embodiments are disclosed which include the shaft being tubular and pressurized, lubricant in the annular chamber and a cable system for urging the rollers together. A splashguard is also provided for preventing water on the surface of the rollers from rewetting the paper.

Abstract: A circular section column with helical liquid flow is divided by a vertical wall 10 into two gas and vapor tight sectors A and B, each sector housing a series of trays.The trays disposed are designated respectively 1a, 2a and 3a for sector A and 1b, 2b and 3b for sector B.The distance D separating each two successive half trays of a given series is constant.On the other hand, the half-trays of one series are each staggered in the axial direction of the column with respect to the half-trays of the other series by a spacing d which is less than half the distance D.This arrangement allows a greater number of half-trays to be housed in a column of a given height, or the height of a column for a given number of trays to be decreased.

Abstract: The separation of coal from pyrite during a froth flotation process is enhanced by the use of an effective amount of a pyrite depressant. The depressant is a hydrophilic nitrogen-sulfur-containing compound.

Abstract: An improved polarization preserving birefringent fiber optic member is provided having cross-sectional circular cladding and core members of soft glasses. A metallic coating of an approximately circular configuration, that is offset from the axis of the core and cladding members, is provided with sufficient thickness to provide an anisotropic variation in compressional strain on the core member to create the anisotropy of the refracted index of the core member for preserving polarization characteristics. The optical fiber can be formed by heating a mechanical composite of a core rod and cladding tube, drawing the core and cladding to form a fused fiber and transporting the drawn fiber through a coating bath to provide the variation in thickness.

Abstract: A glass preform for use in the fabrication of a dispersion shifted single mode optical fiber is produced by a method for comprising steps of inserting a core member consisting of an inner core part made of a germanium-added quartz glass which optionally contains fluorine and an outer core part made of a quartz glass having a refractive index smaller than that of the inner core part in a glass tube made of a fluorine-added quartz glass having a refractive index smaller than that of the outer core part, heating the core member and the glass tube to collapse the glass tube and fuse them together to produce a glass perform. The glass preform comprises a core member consisting of an inner core part made of GeO.sub.2 -SiO.sub.2 glass or GeO.sub.2 -F-SiO.sub.2 glass and an outer core part made of F-SiO.sub.2 glass and a cladding made of F-SiO.sub.2 glass and provides a dispersion shifted single mode optical fiber having reduced attenuation of light transmission in the 1.5 .mu.m wavelength band.

Abstract: A method for forming a terraced structure in the upper surface of a particulate solid bed, typically oil shale, moving upward through an upflow retort and removing particulate solids from the upper surface, which includes rotating a scraping means comprising a shaft having a plurality of scrapers secured thereto arranged in a vertically spaced-apart relationship and in a radially outwardly-stepped relationship relative to a vertical axis of the shaft.

Abstract: An apparatus and method are disclosed for fabricating an expanded beam cylindrical terminated optical fiber taper from a reduced diameter preform rod. The present invention comprises uniformly heating the circumference of a predetermined portion at an intermediate point of the preform rod to a predetermined temperature and then uniformly pulling the preform rod while continuing to heat additional material of the preform rod to produce a pair of expanded beam cylindrically terminated optical fiber tapers connected by a predetermined length cylindrical central section of standard optical fiber having a uniform diameter less than that of the original preform rod.

Abstract: The froth flotation of coal is conducted in the presence of an epoxide conditioner.

Abstract: The invention relates to a process for the isolation of vinyl acetate from a gas mixture containing vinyl acetate, ethyl acetate, water and carbon dioxide formed in the reaction of ethylene with acetic acid and oxygen in the gas phase over catalysts containing palladium or palladium compounds. The gas mixture leaving the reaction zone is passed into a distillation column and the gas mixture leaving the top thereof is cooled. The gas which is not condensed during the cooling is washed with acetic acid in a washing column, an acetic acid solution containing vinyl acetate being obtained. The bottom product from the distillation column is passed to a second distillation column and a side stream containing ethyl acetate is removed from an enrichment zone above the bottom thereof, all or some of the bottom product from the second distillation column, which product chiefly consists of acetic acid, being used for the wash in the washing column. The top vapor of the second distillation column is cooled.

Abstract: In a pulping apparatus including a pulper with a rotor near the bottom therein, the pulper has a sluice outlet at the bottom for acceptable pulp suspension. Above the rotor at a corner of the pulper is a second outlet for suspension and dirt. A conduit leads from the second outlet to a horizontally oriented withdrawal apparatus chamber having a suspension agitating rotor at the end of the chamber opposite the entrance for pulp thereinto. A tangential outlet from the withdrawal apparatus chamber lead to a rotary, perforated sorting drum which permits exit of acceptable suspension and which has a rejected suspension and dirt outlet. A valve in the inlet to the withdrawal apparatus chamber is periodically and cyclically opened to permit periodic replacement of the suspension in the withdrawal apparatus chamber, and the suspension which has been agitated in the withdrawal apparatus chamber then moves to the sorting drum.

Abstract: A blow box for thermal tempering of panes of glass is disclosed. To temper different sizes of glass, the air supply to selected blow tubes or blow tube groups in a blow box having a blow nozzle field disposed to handle relatively large panes of glass is blocked in the edge areas of the blow box. In this manner, the blow nozzle field supplied with forced air is adapted to the shape and size of the glass pane to be tempered. The adaptation of the blow nozzle field to the shape and size of the glass panes takes place, for example, with the aid of a template-like slide block having an opening corresponding to the glass pane, which slide block is arranged inside the air distributing box immediately in front of the front plate provided with the nozzle pipelets and which can be exchanged for a different slide block.

Abstract: The method of beneficiating a phosphate ore comprising apatite and including dolomitic impurities comprising reagentizing the ore having a particle size in the range of 75 .mu.m to about 420 .mu.m with an aqueous solution having a pH of from 3.5 to 4.5 and containing a fatty acid anionic collector and sodium chloride and subjecting the ore to froth flotation to float away the dolomitic impurities.

Abstract: An apparatus for fabricating an optical fiber preform having a support for rotatably holding a reaction tube, a raw material supply unit for supplying a glass raw material from one end of the reaction tube to the interior of the reaction tube and a heater for heating the reaction tube by reciprocating in the axial direction of the reaction tube which comprises a pressure measuring unit at the other end of the reaction tube, a gas pressure control chamber having a gas inlet and an exhaust port, and a blower capable of controlling the introduced gas pressure according to the measured value of the pressure memasuring unit in the gas inlet. Thus, the apparatus can accurately control the internal pressure of a reaction tube in good responsiveness.

Abstract: A method for producing a glass preform for an optical fiber which comprises the steps ofinserting a glass rod from one end of a glass tube while supplying a gas from the other end of the glass tube, flowing the gas through a clearance between the glass rod and the glass tube, exhausting the gas from said one end of the glass tube to outside of the glass tube, andheating and collapsing the glass tube on the glass rod to integrate them and to form the glass preform, which method yields a glass preform from which an optical fiber having improved strength and low attenuation of light is produced.

Abstract: A method for producing a glass preform for optical fibers in which fluorine is efficiently incorporated into the preform without incorporation of Fe or Cu. A fine glass particle mass, made primarily of quartz, is converted into transparent glass by heating it in a gas atmosphere containing at least a fluorine-based compound gas and a chlorine-based compound gas. The preferred heating range is 1,100.degree. to 1,400.degree. C.

Abstract: A glass body having a graded (substantially Gaussian) index profile is produced by a process that comprises providing a doped porous body (e.g., having a uniform dopant distribution), heat treating the porous body in a halogen-containing atmosphere, and consolidating the porous body into the glass body. The heat treatment removes a predetermined portion of the dopant from the porous body, such that the radial dopant profile in the glass body differs from the initial profile in the porous body, and such that the Gaussian index profile results. Exemplarily, the porous body is a uniformly germania-doped, VAD-produced, high-silica rod having radially decreasing density, and the heat treatment comprises an 8-hour densification soak at 1300.degree. C. in 20% Cl, 80% He. In a preferred embodiment, silica overcladding is deposited on a graded index core rod produced according to the invention, and fiber drawn from the resulting composite glass body.

Abstract: An optical fibre is provided with a coating by coating the fibre (1) with a coating material (4) on-line with the fibre drawing process (2) and employing a laser beam (6) to locally heat the coating material whereby to change its physical or chemical properties. Metallic glass coated fibres, useful for hermeticity and sensor applications, can thus be achieved in multikilometer lengths by fusing metallic glass forming alloy coatings to a fibre. Alternatively, polymer coatings may be cured by laser beam local heating.

Abstract: A method of making optical waveguides is disclosed in which, to fabricate a preform, glass forming pulverulent material is filled into a mold by means of one or more screw conveyors. The quantity of glass forming pulverulent material filled into the mold per unit of time is increased by passing a suitable gas through the apparatus. Thus, the quantity conveyed per unit of time can also be controlled by adjusting the gas pressure. By using a dry gas, the moisture content of the powder can be reduced.