Abstract: In a falling film evaporator of the vertical-tube type in which liquid to be evaporated is supplied at the top on the outer surface of vertical heat exchanger tubes and the heat medium is supplied to the heat exchanger tubes at the bottom for flow inside the same, at least one larger tube element than the heat exchanger tubes is disposed between and fixed to tube plates at the both ends of the group of tubes to stabilize the group of tubes against tension and especially compression stresses.

Abstract: The flotation of desired mineral ores is selectively depressed by the use of an effective amount of a polycarboxylic acid or salt thereof in a reverse flotation process. As an example, the flotation of iron-containing minerals, such as iron oxides or iron powder, is selectively depressed when compared to the flotation of silicate gangue thus facilitating the recovery of the desired mineral by the use of an effective amount of a polycarboxylic acid or salt thereof such as sodium polyacrylate.

Abstract: The invention is reagents and procedures for determining an amount of cations present in a sample, the reagent comprising one or more chromogenic cryptand compounds of formula I ##STR1## wherein k and j, either same or different, are equal to 1 to about 5;m and n, either same or different, are equal to 0 to about 4;a and e, either same or different, are equal to 0 to about 2;b and d, either same or different, are equal to 0 to about 5;R, either same or different, is hydrogen, lower alkyl, lower alkylidene, lower alkenyl, allyl, or aryl; and-Q- is ##STR2## wherein X is CH, N, or COH; andY includes ##STR3## except that when Q is ##STR4## wherein Y is selected from the group consisting of p-nitrophenylazo, 3-phenylisothiazalyl -5-azo, isothiazolyl-5-azo, thiazolyl-5-azo, 2,4,6-trinitrophenylazo, p-nitrostyryl, p-benzoquinonemonoimino and bis-(p-dimethylaminophenyl)hydroxymethyl, then the following condition cannot be present: that simultaneously b is equal to 0 or 1, d is equal to 0 or 1, j is equal to 1, n is e

Abstract: An apparatus having a liquid-permeable belt for receiving cellulose pulp, a liquid supply device for discharging treatment liquid on the cellulose pulp, and a container extending across the entire width of the belt for collecting treatment liquid penetrating the belt. The container is adapted to maintain a treatment liquid level at such a distance from the belt so that the formation of foam from treatment liquid is reduced. The container includes a liquid outlet for discharging the treatment liquid and a vapour outlet for discharging vapours and gases from the bottom of the container. The vapour outlet communicates with a passageway within the container, which passageway is formed as a pipe or is partially defined by a container wall. A deflector can be provided on the container for operatively deflecting treatment liquid away from the passageway.

Abstract: An apparatus for producing bends in optical bends in optical fibers comprising a pair of plates hingedly connected along one edge of each of the plates so that the plates may lie in face-to-face contact and may be hingedly separated, means defining a cavity between the plates when in face-to-face contact, the cavity having two portions for receiving lengths of a fiber on opposite sides of a bend to be formed, the portions being joined at an apex section, means defining an opening into the cavity at the apex section, a fiber channel in each of the portions, the fiber channels being mounted in the portions for relative movement in the cavity to a desired bend angle while the apex of the desired angle is positioned at the opening in the apex section, and pulling means for acting on an optical fiber in the channels when the plates are in face-to-face contact and thereby positioning a fiber at the desired angle whereby the apex of the bend of the fiber is accessible through the opening; several variations of the a

Abstract: For the preparation of an ether, e.g., tertiary amyl methyl ether, an olefin-containing feed stream is catalytically etherified with an alcohol, e.g., methyl alcohol. The etherification product is fractionally distilled into an overhead fraction containing essentially unreacted, light hydrocarbons and unreacted alcohol and into a bottoms fraction containing essentially the desired ether. The overhead fraction is condensed and cooled to resultant immiscible phases, of which one contains essentially the alcohol and the other contains essentially the hydrocarbons, are removed separately from each other. Water may be added to the overhead stream to facilitate the formation of the two liquid phases.

Abstract: A method of producing polarization-maintaining single-mode optical waveguides is provided wherein the preform from which the optical waveguide is produced consists of a tube, a rod of core and cladding material centrally disposed in said tube, and two differently doped pairs of filler rods disposed about said rod, the two rods of each pair being disposed diametrically opposed to each other with respect to said rod. Maximum polarization maintenance of the optical waveguide being produced is achieved by choosing the diameter ratios so that each filler rod rests against the central rod, against the inside wall of the tube, and directly against the two filler rods of the respective other pair.

Abstract: A method of preparing printed circuit boards is described in which the solder mask is applied over a thin layer of copper oxide covering the copper circuit traces, the copper oxide layer being that which remains after stripping the tin or tin-lead alloy etch resist.

Abstract: An apparatus for etching supports that have deposited thereon an etchable metal with an etching medium, which apparatus includes an etching chamber, means to convey the supports with metal deposited thereon through the etching chamber, a plurality of nozzles which are positioned to spray etching medium containing acid on the supports as they move through the etching chamber, a sump for receiving residual etching medium withdrawn from the etching chamber, a first circulating system for circulating residual etching medium from the sump back to the plurality of nozzles, a reservoir for an oxidizing agent, a device for regulating the addition of oxidizing agent into the circulating system in an amount which is stoichiometrically in excess of that required to remove metal from the supports, a chamber containing a metal which will react with the oxidizing agent, a second circulating system for circulating residual etching medium from the sump through the chamber containing a metal, a regenerating chamber to receive

Abstract: An improved process of RIE plasma attack of the layer of dielectric material on the surface of wafers of semiconductor material, in correspondence of areas purposely defined by masking, for exposing the underlying semiconductor crystal, in preparation for depositing a layer of material of metallic conduction. After having removed a certain thickness of dielectric according to the known technique, the conditions of attack are modified, substituting the plasma gases and reducing the "bias". The attack is resumed of the residual layer of dielectric and preferably also of a certain thickness of the semiconductor crystal in the same reactor. Ohmic contacts with relatively low contact resistance and great reliability are obtained with a minimum handling of the wafers.

Abstract: A method for producing an optical fiber preform comprising jetting a glass raw material mixture containing at least one phosphorous compound and a fuel gas through a burner, hydrolyzing the raw materials in the flame to form fine glass particles, depositing the fine glass particles to form a porous glass preform, and then sintering the porous glass preform in a stream of an inert gas with removing phosphorus liberated from the preform to produce a transparent optical fiber preform, from which transparent optical fiber preform, an optical fiber having low attenuation at a wavelength of about 1.52 micrometer is produced.

Abstract: In the froth flotation of ore in a column, the froth/pulp interface level and the efficiency of the froth washing operation are controlled by determining a profile of temperatures measured in the froth layer and slurry below the interface. Temperatures are measured with temperature sensing elements immersed in the froth layer and extending to below the interface level. The measured profile is compared with a target profile and deviations are corrected by changing the tailings flowrate or the washwater flowrate to return a measured profile to the target profile. An inflection point in the profile occurs at the interface level. The inflection point in a measured profile is compared with a level set point, and a deviation from set point value is corrected by increasing or decreasing the flow of tailings whereby the interface level returns to its set point.

Abstract: Method and apparatus in the headbox of a paper machine and in its approach pipe system. In the headbox, pulp suspension is fed through the approach pipe system and a pressure screen arrangement, if any, to a distributing header part, from which the pulp suspension flow is conducted through a turbulence generator section and further to a lip section. A pulp suspension jet is discharged from a lip aperture of the lip section onto a forming wire or into a throat defined by a pair of forming wires. At least part of the approach pipe system, the distribution header part, and the turbulence generator section are arranged to have two or several substantially parallel pulp suspension flow passages. The different passages operate substantially simultaneously in parallel, when the headbox has been set to operate in a higher flow rate range.

Abstract: A phosphate ore flotation process for subjecting a phosphate ore containing dolomitic impurities to beneficiation as follows: The flotation feed is first conditioned with fatty acid and fuel oil as collectors and then reconditioned with humic acid as a modifier; subjecting the reconditioned flotation feed to rougher phosphate flotation to collect the rougher phosphate concentrate from the overflow; subjecting said rougher phosphate concentrate to at least one cleaner phosphate flotation; and recovering the phosphate product in the overflow from said cleaner phosphate flotation step.

Abstract: Sealing means for arc discharge tubes employ chamfers formed in the arc tube which mate with frusto-conical portions on sealing disks. Self-centering is thus provided as well as the elimination of one wire stop positioner for holding the sealing disks.

Abstract: The invention concerns a dewatering band press. The wires (2) in the press are wider than the rolls (1), and in view of sealing the edge of the pulp web (3), two rails (4) are placed outside the ends of the rolls, the wires running between the said rails, and a sealing beam (5) is placed between the rails and the wires. The solution is durable and reliable, because it has no readily worn abrading parts.

Abstract: A heavy medium low-specific gravity method for recovering coarse clean coal within a size range of about +28 m and fine clean coal and coal-bearing particles within a size range of -28 x Om from a raw coal feed wherein heavy medium is recovered as a substantially clean product which can be recycled in the heavy medium system. In the method a raw coal feed containing coal, shale and other impurities within a size range of about 3.81 cm.times.0 is mixed withi a heavy medium to produce a slurry of low specific gravity between about 1.27 and 1.70. The slurry is treated in at least one cyclone to separate an overflow product containing substantially all coal and coal-bearing particles from an underflow product containing all shale and sulfur-bearing rejects.The overflow product is treated on standard equipment to separate coarse coal from fine coal and heavy medium. The coarse coal is recovered as a usable product.

Abstract: In an optical fiber preform fabrication method having the steps of decomposing a glass raw material in a flame so that fine glass particles are produced; depositing the fine glass particles on a seed rod to form a porous preform; and consolidating the porous preform into a transparent optical fiber preform, use is made of a burner having a raw material supply orifice for supplying the glass raw material and a plurality of flame forming orifices deposed around the raw material supply orifice sequentially for forming a plurality of flames, respectively. The flame speed V.sub.k of a kth flame, the flame speed V.sub.k+1 of a (k+1)th flame surrounding outwardly of the kth flame and the flow speed Vm of the glass raw material are determined in a suitable manner. The glass raw material is supplied to the multi-flame produced by the burner in which the kth flame is positioned rearwardly of the (k+1)th flame to synthesize the fine glass particles.

Abstract: An assembly of a quench liquid distribution ring and dip-tube with or without a draft tube for use in a hot effluent gas quench cooling zone containing a pool of quench liquid in the bottom in combination with a vertical cylindrical free-flow refractory lined reaction zone of a partial oxidation gas generator. The hot effluent gas from the reaction zone passes through a bottom central discharge outlet and passage and then through a coaxial vertical dip-tube that extends down into a pool of quench liquid. A quench liquid distribution ring that includes an annular rectangular shaped bottom feed quench liquid distribution channel, surrounds the outside diameter of the dip-tube at its upstream end. A quench ring face and cover is provided that comprises a vertical cylindrical shaped leg portion and a top horizontal flat ring plate portion that extends perpendicularly outward from the upstream end of the leg portion.

Abstract: A process for the separation of phosphate minerals from a phosphate-carbonate ore, by flotation, wherein a phenol polymer such as a resol or a novolak, which improves the yield and selectivity of the phosphate minerals with respect to the carbonate minerals, is used in addition to a collector agent in the flotation.