Abstract: In the method for welding a hollow structure of the present invention, a rib is placed between a first joining member and a second joining member, and friction stir welding and fixing a place where the rib is placed between the first and the second joining member are conducted. Thus, friction stir welding is accomplished without changing the shape of an extrusion part or partly changing the shape of the extrusion part with insertion of a simply shaped rib.

Abstract: Provided is a method of amplification of coke oven gas (COG) through reacting high-temperature carbon with carbon dioxide and/or water using waste heat generated in a coke oven. More particularly, a method of amplification of COG including providing a gasification agent including carbon dioxide, water, or a mixture thereof to a COG stream in a carburization chamber of a coke oven and gasifying carbon by allowing the gasification agent to react with carbon in the carburization chamber, and a coke oven apparatus suitable for the method are provided.

Abstract: The present invention provides a method for preparing dialkyl carbonate from urea or alkyl carbamate and alkyl alcohol using an ionic liquid comprising a cation, which produces a hydrogen ion, and a hydrophobic anion containing fluorine with high temperature stability in the presence of catalyst containing a metal oxide or hydrotalcite. Since the present invention can prepare dialkyl carbonate at a pressure lower than those of existing methods, it does not require an expensive pressure control device and peripheral devices for maintaining high pressure including the installation cost. It is also the method for preparing a dialkyl carbonate with high yield, thus improving economical efficiency. Moreover, the method of the present invention hardly produces any waste during the process and is thus an eco-friendly method.

Abstract: A high manganese duplex stainless steel with excellent hot workability, comprising (in weight %): less than 0.1% of C; 0.05-2.2% of Si; 2.1-7.8% of Mn; 20-29% of Cr; 3.0-9.5% of Ni; 0.08-0.5% of N; less than 5.0% of Mo and 1.2-8% of W, alone or composite; the balance Fe and inevitable impurities; and a method for manufacturing the duplex stainless steel, comprising the steps of: solution heating the duplex stainless steel composition at a temperature of 1,050 to 1,250° C., hot working at a starting temperature of 1,130 to 1,280° C. and then ending at a temperature greater than 1,000° C., and then cooling within the temperature range from 1,000 to 700° C. at a cooling rate of more than 3° C./min. The duplex stainless steel exhibits a reduction in area of more than 50% at 1,050° C., and possesses a yield strength of more than 400 MPa, and a corrosion rate of less than 0.36 mm/year, after solution heating.

Abstract: There are provided a method of manufacturing an Fe/Ni-containing material having a low content of sulfur (S) from an Fe/Ni/SO4-containing liquid waste, a ferronickel mass using the Fe/Ni-containing material, and a method of manufacturing the ferronickel mass. The method of manufacturing an Fe/Ni-containing material from an Fe/Ni-containing liquid waste includes: removing SO4 from an Fe/Ni/SO4-containing liquid waste by adding an SO4 neutralizing agent to the liquid waste so that pH of the liquid waste can be maintained to a pH level of 0.5 to 2.5; precipitating Fe and Ni in the form of hydroxide [(Ni,Fe)(OH)] by adding NaOH to the SO4-free solution; washing the precipitate with water; and manufacturing an Ni/Fe-containing material by filtering and drying the washed Ni/Fe-containing sludge.

Abstract: There is provided an effective method for removing mercury comprising injecting NaClO2 into an emission gas containing elemental mercury and NOx; converting the elemental mercury to oxidized mercury by using oxidizing agents produced by the NaClO2 and the NOx; and removing oxidized mercury from the emission gas.

Abstract: An apparatus and method for absorbing and recovering carbon dioxide from flue gas using ammonia water as an absorbent, including an absorption column and a circulation cooler connected to the absorption column so that a high-temperature absorbent is recovered from the absorption column, cooled to a preset temperature, and then supplied again into the absorption column, in order to dissipate absorptive heat generated when carbon dioxide is absorbed from the flue gas.

Abstract: There is provided an effective method for removing mercury comprising injecting NaClO2 into an emission gas containing elemental mercury and NOx; converting the elemental mercury to oxidized mercury by using oxidizing agents produced by the NaClO2 and the NOx; and removing oxidized mercury from the emission gas.

Abstract: Disclosed is a mechanically stabilized earth (MSE) wall system for preventing collapse of a retaining wall. The MSE wall system includes: at least two pillars installed on a front surface of the retaining wall; a plurality of screens installed on a rear surface of the pillar and arranged along a vertical direction to intercept a space between the adjacent pillars; at least a connector installed between the adjacent pillars to preserve a space between the adjacent pillars and prevent the screens from being separated into a front direction; and at least a front panel spaced from a front surface of the screen. Since deformation of the screen which supports the load of the backfilling soil is not transferred to the front panel, it is possible to provide excellent appearance.

Abstract: Provided is a strengthening device to increase the strength of a grout layer. In the strengthening device, clamp members are interconnected and clamped to surround a grout layer on a concrete base, on which an upper structure is installed, so as to increase the strength of the grout layer. Connection members are provided to edges of the clamp members to connect the clamp members. Fastening means is fastened between the connection members in order to enable the clamp members to clamp the grout layer. This strengthening device acts as a mold to facilitate easy construction when grout is placed, and surrounds the grout layer to increase the strength of the grout layer after grout is cured, thereby effectively preventing and minimizing failure of the grout layer caused by loads transferred from an upper structure such as a column member or a bridge bearing.

Abstract: The invention relates to an apparatus and method for manufacturing molten iron. The method for manufacturing molten iron includes producing a mixture containing iron by drying and mixing iron-containing ore and additives, passing the mixture containing iron through one or more successively-connected fluidized beds so that the mixture is reduced and calcined to thereby perform conversion into a reduced material, forming a coal packed bed, which is a heat source in which the reduced material has been melted, charging the reduced material to the coal packed bed and supplying oxygen to the coal-packed bed to manufacture iron, and supplying reduced gas exhausted from the coal-packed bed to the fluidized bed, wherein in the conversion of the mixture to a reduced material, oxygen is directly supplied and combusted in an area where reduced gas flows to the fluidized bed. The apparatus for manufacturing molten iron of the invention uses this method for manufacturing molten iron.

Abstract: A cold spray apparatus having a powder preheating device, capable of obtaining high deposition rate and excellent coating layer under the same spray processing conditions by preheating coating powder before a coating process. Also, a manufacturing method of nano-structured super-high hardness WC—Co coating having high abrasive wear resistance and fracture toughness obtained by spraying WC—Co powder using the cold spray apparatus. In the cold spray apparatus, a gas controller controls gas supply amount of main gas and residual gas (gas that is not supplied toward the main gas), and a gas heater heats the main gas supplied under the control of the gas controller. A powder feeder receives the residual gas under the control of the gas controller and supplies a coating powder together with the residual gas. A powder preheating device preheats the coating powder supplied from the powder feeder, and a mixing chamber mixes the heated main gas with the preheated coating powder.

Abstract: Apparatus and process for producing metal products, in which a metal-containing charge material is melted in a melting unit, and a working gas, in particular an at least partially reducing working gas, is additionally produced in the melting unit. The working gas produced is extracted and if appropriate after cleaning, is used as a carrier gas, at least in part for—preferably pneumatic—transport of an at least partially reduced metal-containing material in the form of fine particles.

Abstract: The invention relates to an apparatus and method for manufacturing molten irons. The method for manufacturing molten irons includes providing a mixture containing iron by drying and mixing iron ores and additives, passing the mixture containing iron through one or more successively-connected fluidized beds to convert the mixture into a reducing material that is reduced and calcined, forming a coal packed bed, which is a heat source in which the reducing material has been melted, charging the reducing material to the coal packed bed and supplying oxygen to the coal packed bed to manufacture molten irons, and supplying reducing gas exhausted from the coal packed bed to the fluidized bed. In the providing a mixture containing iron, exhaust gas exhausted from the fluidized bed is branched to dry at least one of the iron ores and the additives. The apparatus for manufacturing molten irons uses this method for manufacturing molten irons.

Abstract: An electrolysis-type apparatus for treating ballast water using NaOCl and a method thereof is provided. The apparatus includes: a ballast tank; an electrolyzer; a first circulation pump; a second circulation pump; and a controller. The ballast tank is installed in a ship to store seawater. The electrolyzer is connected with the ballast tank and electrolyzes the seawater. The circulation pumps are installed to allow the ballast water to flow into the electrolyzer and to discharge the electrolyzed water containing NaOCl to the ballast tank. The controller supplies power to the electrolyzer so as to control an NaOCl density and controls the circulation pumps. The apparatus and the method safely treat the seawater. Thus, environment pollution and ecosystem destruction can be minimized.

Abstract: The present invention relates to a preform for a glass ferrule and a fabrication method thereof. It is an objective of the present invention to fabricate dual hole ferrules having various distances between two holes by using a single preform. It is another objective of the present invention to fabricate a preform for a dual hole glass ferrule by a simple process. To meet the above and other objectives, the present invention provides a preform for a glass ferrule, comprising two holes which are formed through the preform and exit out both side cross-sections of the preform, wherein the two holes are symmetrical to the center in a diameter direction of the preform and a distance between the two holes changes in a lengthwise direction of the preform.

Abstract: An apparatus and method for absorbing and recovering carbon dioxide from flue gas using ammonia water as an absorbent, including an absorption column and a circulation cooler connected to the absorption column so that a high-temperature absorbent is recovered from the absorption column, cooled to a preset temperature, and then supplied again into the absorption column, in order to dissipate absorptive heat generated when carbon dioxide is absorbed from the flue gas.

Abstract: Apparatus and process for producing metal products, in which a metal-containing charge material is melted in a melting unit, and a working gas, in particular an at least partially reducing working gas, is additionally produced in the melting unit. The working gas produced is extracted and if appropriate after cleaning, is used as a carrier gas, at least in part for—preferably pneumatic—transport of an at least partially reduced metal-containing material in the form of fine particles.

Abstract: Disclosed is a mechanically stabilized earth (MSE) wall system for preventing collapse of a retaining wall. The MSE wall system includes: at least two pillars installed on a front surface of the retaining wall; a plurality of screens installed on a rear surface of the pillar and arranged along a vertical direction to intercept a space between the adjacent pillars; at least a connector installed between the adjacent pillars to preserve a space between the adjacent pillars and prevent the screens from being separated into a front direction; and at least a front panel spaced from a front surface of the screen. Since deformation of the screen which supports the load of the backfilling soil is not transferred to the front panel, it is possible to provide excellent appearance.

Abstract: An apparatus for controlling gas layer thickness on the surface of casting rolls in a twin roll strip caster includes: a pair of chambers fixedly mounted on both lateral portions of the meniscus shield in a width direction of a strip; blocking units for blocking introduction of pollutants into the molten metal pool, wherein each of the blocking units includes front and rear barrier members which are mounted on each of the chambers and in close contact with an outer periphery of each casting roll and a blower for injecting inert gas toward the outer periphery of each casting roll; operating units for adjusting the thickness and the width of gas layers at both ends of the casting rolls, wherein each of the operating units includes suction lines connected with each chamber to transmit a suction force to ends of each casting roll and a pair of movable plates slidably assembled to both side portions within each chamber for being reciprocated by movable members; and a control unit for controlling the suction force