Abstract: A method for sheet forming a remarkably waterproof gypsum hardened body, in which a main component consisting of gypsum dihydrate, slag and calcium hydroxide and additives are added with a part of the main component coated with a hydrophobic diorganopolysiloxane fluid having a kinetic viscosity of 10-10,000 CS at 25.degree. to be sheet formed and cured. The hydrophobic diorganopolysiloxane fluid is uniformly dispersed through the sheet formed gypsum hardened body and its strong water repelling property makes the gypsum hardened body remarkably waterproof to be used suitably as both interior and outdoor construction materials.

Abstract: A demolition agent which acts by means of expansive stress generated upon hydration and which is prepared by calcining limestone at 1300.degree. to 1600.degree. C. to produce a hard-burned quick lime whose crystal sizes are 10 to 100 micron, pulverizing the resulting hard-burned quick lime to 1500 to 5000 cm.sup.2 /g (Blaine), mixing 5 to 70 parts by weight of a hydraulic material to 30 to 95 parts by weight of the hard-burned quick lime and furthermore adding 0.1 to 5 parts by weight of an admixture comprising a water reducing agent to 100 parts by weight of the mixture of the powdery hard-burned quick lime and the hydraulic material.The demolition agent is used as an aqueous slurry. The slurry is filled into holes of a brittle material to demolish the brittle material by means of expansive stress generated upon hydration.

Abstract: The present demolition agent for brittle materials is prepared by pulverizing a clinker which is obtained by mixing a calcareous material, a siliceous material and gypsum at the molar ratio of CaO/SiO.sub.2 =5.0-14.4 and CaSO.sub.4 /SiO.sub.2 =0.13-1.19 and burning the mixture under an oxidizing atmosphere to 1350.degree.-1550.degree. C. The main components of the clinker thus obtained consist of 24-65% by weight of 3CaO. SiO.sub.2 crystals, 30-60% by weight of CaO crystalline particles and 5-17% by weight of CaSO.sub.4, wherein more than 50% by weight of said CaO crystalline particles is included in the large 3CaO.SiO.sub.2 crystals grown.The present demolition agent is used to break brittle materials by means of the expansive stress of aqueous slurry of the demolition agent poured into the hole of the brittle materials.

Abstract: This invention relates to a continuous process for electrostatically coating a substantially axially symmetrical object with pulverized material, characterized by conveying said object by means of a conveyor-type holding device into an electrostatic coating chamber equipped with silent discharge plate electrodes on both sides of the chamber walls: feeding electrically charged pulverized material into said chamber: electrostatically coating said object with said pulverized material by the action of silent discharge from said electrodes: and removing surplus pulverized material from the specific parts of said object by suction.

Abstract: A process for producing a fiber-reinforced hardened body comprising mixing gypsum and slag in a ratio by weight of the former to the latter between 3:7 and 7:3 to prepare a main starting material, adding to the main starting material 1 - 30% by weight of reinforcing fiber, 0.1 - 5% by weight of alkali salt substance and 0.1 - 5% by weight of aluminum sulfate-containing substance, the respective amounts being based on the weight of the main starting material, further adding water to knead and mold the resulting starting material mixture, and curing the molded starting material mixture under normal condition or steam-curing the molded starting material mixture at 90.degree. C. or below.

Abstract: This invention relates to mixtures of molding sand which comprise a mixture of a molding sand with a rapid hardening cement containing calcium aluminate as amorphous glass and/or crystals, and/or calcium haloaluminate, a polymer water holding agent and a lime, or mixture of a molding sand with the above-mentioned rapid hardening cement, a polymer water reducing agent, a lime, and, if necessary, a foaming agent, and in either case with water. The mixture also provides a method of mixing the ingredients except for water and then kneading the mixture with water.

Abstract: Forming coating layers at least on the whole inner side wall and top peripheral opening edge of a paper cup with synthetic resin to be closely adhered, also forming a coating layer with synthetic resin on the inside face of a bottom paper plate closely adhered, said coating layer at the lower peripheral edge of said inner side wall and the bottom coating layer are merged to be an integral part along the whole inner face of the cup, thereby leakage of liquid contained therein by penetration from said side wall, particularly from overlapped portion of side wall and from jointed portion of the side wall and bottom plate is prevented; also in the paper cup with a lid, leakage of liquid from the top opening end is prevented.

Abstract: In a pair of surface-shaped silent discharge electrodes opposed to each other and separated by a predetermined space therebetween, phases of alternating voltages are applied to said respective silent discharge electrodes shifted in phase with respect to each other so that a silent discharge may arise alternately on either one of the electrode surfaces. A second alternating voltage is applied between the silent discharge electrodes and is alternatingly varied at a fundamented frequency twice as high as the frequency of the first alternating voltages applied to said surface-shaped silent discharge electrodes and is not inverted in polarity during the period when the silent discharge exists on either one of the electrode surfaces. Powder particles are passed through the space which separates the pair of surface-shaped silent discharge electrodes and charged in either positive or negative polarity continuously at a high efficiency.

Abstract: A process for manufacturing a rapid hardening portland cement clinker containing a calcium halo-aluminate having the formula; 11CaO.7Al.sub.2 O.sub.3.CaX.sub.2, in which X is a halogen, characterized by adding at least one sulfur compound selected from calcium sulfate, calcium sulfite and calcium sulfide to the mixed raw materials comprising mainly an aluminous material, a calcareous material, a silicious material, an iron source and a halogen source, and burning the obtained mixture in an oxidizing temperature.

Abstract: Apparatus comprising means for dispersing comminuted limestone in a stream of hot gas and calcining it to form quicklime; a calcining chamber into which comminuted gypsum and the stream of hot gas containing the quicklime are introduced wherein the gypsum is calcined and thoroughly mixed with the quicklime; a gas-solids separator for separating the calcined gypsum and quicklime from the gas stream; and hydration means for hydrating the quicklime and gypsum whereby any phosphoric acid in the gypsum reacts with the hydrated quicklime to form insoluble calcium phosphate.

Abstract: Silent discharge electrodes are provided in the proximity of a powder paint injection opening to generate silent discharge between these electrodes. Thus the voltage applied between a body to be painted and a painting apparatus and the discharge current flowing from said painting apparatus to said body to be painted can be respectively regulated independently of each other, and the flow pattern of ion currents in the painting space can be appropriately regulated, whereby the painting efficiency is enhanced and the quality of the painted film is improved.

Abstract: This invention relates to a process for inhibiting corrosion of iron or steel such as reinforcing bars etc. placed in cement products such as paste, mortar and concrete containing a chloride which comprises adding a nitrite and a phosphoric ester, a nitrite and a boric ester or a nitrite and a mixture of a phosphoric ester and a boric ester to the cement.

Abstract: A face-silent discharge electrode which includes plural parallel electrode bars separated from each other at a distance and arranged in a face is disposed to confront a substrate. A powder coating material is supplied in the space between said electrode and said substrate. An AC voltage is impressed on the electrode bars adjacent each other to generate a silent electric discharge over the entire surface of said face-silent discharge electrode. Concurrently, a DC voltage is impressed between the electrode bars and the substrate so that the powder coating material may adhere to a surface of the substrate to form a layer of uniform thickness.

Abstract: This invention relates to an apparatus for calcining cement having a suspension preheater containing an auxiliary furnace in the preheater part, characterized in that said apparatus has an adjustable throttle positioned between a kiln and a mixing chamber where a combustion gas from the kiln and a combustion gas from the auxiliary furnace are joined and mixed with each other, said adjustable throttle comprising a quadrilateral flue where at least one of the walls is movable in order to control the amount of combustion gas from the kiln.

Abstract: This invention relates to a process for continuously producing a dense board of cement-like material reinforced by glass fiber, which comprises (1) preparing a slurry of cement-like material; (2) simultaneously spraying the cement-like slurry and short lengths of glass fiber on a suction conveyor in such a manner that the cement-like slurry stream and the glass fiber stream intersect on the suction conveyor to form a dense mat of an intimate mixture of the two; and (3) dehydrating the mat by pulse-like intermittent suction using one or more suction boxes before the cement-like material begins to set, and to an apparatus used in carrying out the process.

Abstract: This invention relates to a process for continuously producing a board of cement-like material reinforced by fibrous material, which comprises (A) preparing granules of cement-like material by adding water to powdery cement-like material; (B) preparing a granular mixture of the cement-like material and fibrous material by mixing the above prepared granules of cement-like material with short lengths of fibrous material dispersed in air; and (C) forming said granular mixture into a board under compression, optionally with the addition of water.

Abstract: In an electric field curtain system, a plurality of linear electrodes are embedded in an insulator layer in parallel to each other along the surface of said insulator layer so that silent discharge forming curved electric lines of force which are outwardly convex may be produced on the surface of said insulator layer, the width of each of said plurality of linear electrodes is chosen equal to or less than 3 mm, and the interval between the respective linear electrodes is selected within a limited range, whereby every charged particle may be floated away from the surface of the insulator layer so as not remain on said surface.

Abstract: A novel gap type surge absorber is disclosed. The surge absorber comprises a plurality of carbon thin films isolated from each others at short distances attached to the surface of an insulating body and one material selected from the group consisting of a metal, an alloy and a conductive adhesive as an electrode fixed to each of the plural carbon thin films. The surge absorber is an element based on a new mechanism that when a surge voltage reaches a prescribed value, a discharge is generated owing to emission of electrons between the carbon thin films and thereby a creeping discharge is initiated between the electrodes. The surge absorber has a small electrostatic capacity as well as a small discharge lag and is capable of cutting off a follow current.

Abstract: This invention relates to a method for retarding the setting time of rapid hardening cement which comprises adding a boric compound to cement manufactured by adding insoluble anhydrite to clinker powder containing 11CaO.7Al.sub.2 O.sub.3.CaX.sub.2 or adding the clinker to insoluble anhydrite and intergrinding the mixture, and a method for still more retarding the setting time of rapid hardening cement which comprises adding a boric compound to cement containing a set-retarding agent other than the boric compound.