• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.469-472
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• 2008

This research suggest one-body type scrapped styrofoam crusher with sprayed air (or water), which at present separately composed of dust eliminator, air supplier and crusher. Air (or water) that supplied from compressor injected to rotating twin roller through axis hole, and sprayed out of fine hole on the surface. The crusher that manufactured with sprayed air (or water) can make high-quality primary styrofoam removed pollution and dust. In case of mixed sprayed air and water, clean degree of crushed styrofoam was higher than single sprayed air. This could be contributed to reduce environmental pollution, cost and space in standpoint of recycling scrapped styrofoam.

• Journal of Ocean Engineering and Technology
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• v.12 no.1
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• pp.32-38
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• 1998

This paper is to investigate of microhardness, adhesive strength, tensile strength, and fatigue strength of ceramic sprayed steel. Rotary bending fatigue tests have been conducted at room temperature in air and 3% NaCl solution using specimens of carbon steel(S45C) with sprayed coating layers of Ni-4.5% Al(under coating) and $TiO_2$ (top coating). The microhardness has been improved at $800^{\circ}C$ heat treatment and 150mm spraying distance. Tensile strength of the sprayed steel is dependent on the substrate strength. The fatigue strength of the sprayed steel is larger than that of substrate due to blasting and constraint surface of plastic deformation effect. In low stress level, the corrosion fatigue strength of the sprayed steel were lower than that of fatigue strength in air by corrosion.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.141-144
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• 2006

The main purpose of this study is to develop a Sprayed FRP repair and strengthening method, which is a new technique for strengthening the existing concrete structures by mixing carbon or glass shot fibers and the epoxy or vinyl ester resins with high-speed compressed air in open air and randomly spraying the mixture onto the concrete surface. At present, the Sprayed FRP repair and strengthening method using the epoxy resin has not been fully discussed. In order to investigate the material property of Sprayed FRP, this study carried out tensile tests of the material specimens which are changed with the combinations of various variables such as the length of shot fiber and mixture ratio of shot fiber and resin. These variables are set to have the material strength equal to one layer of the FRP sheet. As a result, the optimal length of glass and carbon shot fibers were derived into 3.8cm, and the optimal mixture ratio was also deriver into 1:2 from each variable. And also, the thickness of Sprayed FRP to have the strength equal to one layer of FRP sheet was finally calculated.

• Journal of Industrial Technology
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• v.33 no.A
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• pp.93-99
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• 2013

Shotcrete has been referred to as gunite, pneumatically applied mortar or concrete, sprayed concrete or mortar. There are sound reasons why sprayed mortar is one of the best portland cement based material for repairing old concrete structures. However, it is difficult to find the research results on the latex-modified mortar nevertheless on the impact of air onto the fresh and hardened properties of latex-modified mortar. So, the main experimental program included strength test, slump test, rapid chloride permeability test, image analysis for air void system, and chemical attacks with the main experimental variables of latex content, fine aggregate content, water-cement ratio, and air foamer content.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.133-136
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• 2006

The main purpose of this study is to develop a Sprayed FRP repair and strengthening method, which is a new technique for strengthening the existing concrete structures by mixing carbon or glass shot fibers and the epoxy or vinyl ester resins with high-speed compressed air in open air and randomly spraying the mixture onto the concrete surface. At present, the Sprayed FRP repair and strengthening method using the epoxy resin has not been fully discussed. In this study, a series of experiments are carried out to evaluate the strengthening effects of the flexural and shear concret beams strengthened with the Sprayed FRP method. The results revealed that the strengthening effects of the flexural and shear specimens are similar, compared to those of the FRP sheet.

• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.421-431
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• 2007

The main purpose of this study is to develop a sprayed FRP repair and strengthening method, which is a new technique for strengthening the existing concrete structures by mixing one of the carbon or glass chopped fibers and one of the epoxy or vinyl ester resins with high-speed compressed air in open air and randomly spraying the mixture onto the concrete surface. At present, the sprayed FRP repair and strengthening method using the epoxy resin has not been fully discussed. In order to investigate the material property of the sprayed FRP, this study carried out tensile tests of the material specimens, which were changed with the combinations of various variables including the length of chopped fiber and the mixture ratio of chopped fiber and resin. These variables were set to have the equal material strength, compared with that of one layer of the FRP sheet. As a result, the optimal length of glass and carbon chopped fibers was fumed out to be 38 mm, and the optimal mixture ratio between chopped fiber and resin was also turned out to be 1 : 2 from each variable. And also, the thickness of the sprayed FRP to have the equal strength to one layer of the FRP sheet was finally calculated. In is study, a series of experiments were carried out to evaluate the strengthening effects of flexural beams, shear beams and damaged beams strengthened with the sprayed FRP method, respectively. The results revealed that the strengthening effects of the flexural and shear specimens were reasonably similar to those of the FRP sheet, and the developed Sprayed FRP technique is able to be used as a strengthening scheme of existing RC building.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.488-492
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• 2007

In this study, experiment was done to verify the relationship between sprayed water's pH and gas removal efficiency of the Air Washer system. The experiment was done with sprayed water's pH in between pH 4.7 to 7.7, and Ion Chromatography analysis was used to identify the system's gas removal efficiency. As a result, $NH_3$ is removal efficiency decreased under 50% above pH 7, and $SO_X$ and $NO_X$ removal efficiency decreased under pH 6. Through this research, the optimum pH operating condition of the Air Washer System was conformed to be in range between pH6 to pH6.5.

• Journal of Advanced Marine Engineering and Technology
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• v.15 no.3
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• pp.39-44
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• 1991

The purpose of this investigation is to examine the effects of spraying conditions on the mechanical properties of flame-sprayed titania ceramic coating layer. Titania ceramic was sprayed onto the mild steel substrate under the various spraying conditions. Spraying distances were 100, 150, 200, 250mm respectively and pinch air pressures were 0.2 0.3, 0.4 MPa at each spraying distance. The mechanical properties such as microhardness, adhesive strength and erosion wear resistance were tested for the specimens sprayed under the various spraying conditions above mentioned. The optimum operational conditions obtained through the experimental results were 150mm of spraying distance and 0.3 MPa of pinch air pressure.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.6
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• pp.1941-1947
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• 1996

Droplet size measurement technique was established for the sprayed viscous fluid by virtue of the installation of the sprayed-droplet size measurement system employing light scattering method. Atomization test results showed that the mean droplet size of the sprayed viscous fluid is decreased with the increase of the mass ratio of air to fuel and in case of the same air/fuel ratio, also with the increase of viscous fluid flow rate, and is increased with the distance from atomizer tip. Basic design data for the manufacture of external-mixing type, Y-Jet type, and internal-mixing type atomizers was acquired from the atomization tests.

• Journal of the Korean institute of surface engineering
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• v.22 no.4
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• pp.185-196
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• 1989

The surface modification of a mild and stainless steel by alumina sprayed coating were studied. The effects of surface roughness and bond coating layer on the adhesive strengthy and durability of sprayed specimens were also investiated. The adhesive strength of ceramic coating was affected by surface roughness and bond coating layer thinkness. That showed excellent undergrit blast time and bond coating layer; 60 sec and 0.15-0.33mm, respectively. The adhesive strength and densification of sprayed coating with air pressure were superior to those of without and fracture was mainly occured at alumina-bond coating interface. Under ambient atmosphere at $800^{\circ}C$, the oxides existed within bond coating layer promote diffusion of oxygen to lower durability of sprayed specimens. In this case, fracure was occured at sudstrate-bond coating interface.