• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.3
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• pp.5-13
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• 2016

This study investigated the effects of different factors on the migration of a fluorescent whitening agent (FWA) from paper treated with FWAs to non-fluorescent papers. FWA migration experiments were carried out in vertical and friction contacts between the papers dyed with FWAs and non-fluorescent papers. During the experiments, we identified the effects of the addition and types of FWAs, contact time, temperature, and relative humidity (RH) on FWA migration. The fluorescence indices of the non-fluorescent papers were measured before and after the migration experiments, and the Student's t test, a statistical tool, was utilized to compare results from different migration experiments. In vertical contact experiments, FWA migration to non-fluorescent paper was observed at $30^{\circ}C$ and 70% RH; this was attributed to the high moisture content of the paper. FWA migration did not occur significantly at $23^{\circ}C$ and 50% RH. In the friction contact experiments, FWA migrations were identified at both temperature conditions and RH percentages. The addition and types of FWAs did not increase the fluorescence index of non-fluorescent papers. Therefore, it was concluded that the moisture content of paper and the friction contact affected FWA migration from the papers containing internal and surface FWAs.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.172-172
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• 2016

Dual-beam experiments (Focused ion beam - Orientation mapping microstructure, FIB-OIM) is a widely used experimental tool because this experiments tool available alternates between automated serial sectioning and EBSD with the help of dual beams. We investigated the reconstruction procedure for analysis tool which three-dimensional internal microstructure using Ni superalloy(IN100) and ZrO2. As a results, we observed annealing twin boundary each layer in Ni superalloy(IN100) and fairly isotropic internal microstructure in ZrO2 using marching cubes algorithm. According to these results, this procedure is reconstructed well and we gained ability to arrange the EBSD map and internal microstructure.

• Journal of the Korean Society of Safety
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• v.11 no.3
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• pp.160-167
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• 1996

The construction waste concrete produce from the demolished concrete structures. These waste concrete materials are useful and valuable for fill and subgrade and are considered to use as the subgrade material of the road. To use the subgrade of the road with the waste concrete, the several experiments involved with compaction test and laboratory C. B. R. etc. are performed. These experiments are compared with criteria of the road construction manual. It is shown that the quality of the construction waste concrete satisfies that of the subgrade mentioned in the road construction manual.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2430-2435
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• 2015

In order to achieve high flexibility in manufacture, analysis of chip's shape is one of the most important problems. This paper describes the change of machining characteristics in workpiece materials depending on turning clearance angle. The experiments start from choosing three workpiece materials that are SM45C(machine structural carbon steel), STS303(stainless steel), SCM415 (chrome-molybdenum steel). Then, the experiments show specifically how features of selected materials changed when they were processed with diverse machining depths and with feed rate starting from fixed rotational speed. Especially, the experiments were also analyzed in chip's shape and wear of insert tip. In conclusion, these experiments show that chip's shape was changed by quality of the materials, depth of cut, and conveying speed. When machining feedrate and machining depth were 0.10mm/rev and 0.3mm respectively, workpiece materials showed the best shapes, not categorizing quality of the materials and machining characteristics.

• Smart Structures and Systems
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• v.22 no.1
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• pp.71-79
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• 2018

The nonlinear vibration analysis of a magneto-rheological elastomer (MRE) sandwich plate is conducted experimentally. Experiments have been performed in order to construct the frequency-response curves in the vicinity of the fundamental natural frequency of an MRE sandwich plate (plate A) in either the absence or presence of a localised external magnetic field at 3 different geometrical locations, for both small and medium magnetic fields. Furthermore, experiments have also been conducted on a pure aluminium plate (plate B) with an equal thickness to the MRE sandwich plate (plate A) in order to examine the influence of the MRE layer on the nonlinear dynamics of the system. An electrodynamic shaker was used to directly force each system and the displacement at the centre of the plate was measured. Meanwhile, permanent magnets were used to apply a localised magnetic field for the experiments where the MRE sandwich plate was subject to an external magnetic field. It was observed all the MRE systems displayed strong hardening-type nonlinear behaviour, however, with increasing magnetic field this behaviour transitioned to a weak hardening-type nonlinearity.

• Advanced Composite Materials
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• v.17 no.2
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• pp.177-190
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• 2008

As the first step in discussing the reliability of composite structures, a fundamental study was performed to obtain the scattering characteristics of glass-fiber reinforced plastics (GFRP) and woven carbon fiber reinforced plastics (WCFRP) as well as a reference metal. The Euler buckling load was obtained experimentally for each material. The experiments were conducted for specified rectangular specimens with simply supported edges. A new attachment to realize the simply support boundary conditions for composite materials have been prepared before these experiments. The scattering data in the results for GFRP and WCFRP composites were compared with those of a typical metal of aluminum alloy. The experimental data were also compared with numerical simulations including the uncertainties.

• Korean Journal of Metals and Materials
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• v.48 no.5
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• pp.430-435
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• 2010

Solvent extraction experiments of Rh(III) and Ir(IV) were performed on the HCl solution by using Alamine336 and TBP. The extraction percentage of Rh and Ir by Alamine336 was much higher than that by TBP. For the solvent extraction with Alamine336, the extraction percentage of Rh and Ir decreased with a HCl concentration. However, the extraction percentage of both metals by TBP was below 12% in our experimental range and increased with an increasing HCl concentration of up to 8 M. From the mixed solution of Ir with an excess SnCl$_{2}$, most of the tin was extracted by Alamine336 and TBP. However, the extraction percentage of Ir by Alamine336 was reduced and no iridium was extracted by TBP. The extraction behavior of Ir and Sn was investigated by scrubbing experiments on the loaded Ir with a SnCl$_{2}$ solution.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.573-576
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• 2003

In this paper the following conclusions were obtained after examining and analyzing data through the various experiments by adopting automobile's piston as the experimental materials among the automobile materials which are being commercialized. The various experiments have been carried out with the object of presenting the selection of rational. economic materials and criterion according to the improvement of machining characteristics by grasping the strength and weakness of existing various materials and using the effects of metallic structure variables as well as satisfying the required conditions.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.147-150
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• 2004

In order to describe the mechanical behavior of highly anisotropic and asymmetric materials such as fiber­reinforced composites, the elastic-plastic constitutive equations were used here based on the recently developed yield criterion and hardening laws. As for the yield criterion, modified Drucker-Prager yield surface was used to represent the orthotropic and asymetric properties of composite materials, while the anisotropic evolution of back­stress was accounted for the hardening behavior. Experimental procedures to obtain the material parameters of the hardening laws and yield surface are presented for 3D Circular Braided Glass Fiber Reinforced Composites. For verification purpose, comparisons of finite element simulations using the elastic-plastic constitutive equations, anisotropic elastic constitutive equations and experiments were performed for the three point bending tests. The results of finite element simulations showed good agreements with experiments, especially for the elastic-plastic constitutive equations with yield criterion considering anisotropy as well as asymmetry and anisotropic back stress evolution rule.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.6
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• pp.762-781
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• 2018

This paper presents the ballistic armor performance examination and thickness estimation for the latest naval ship structure materials in the Republic of Korea. Up to date, research regarding methods of ballistic experiments establishing database on the latest hull structure materials as well as a precise method of estimating required thickness of armor against specific projectiles have been rarely researched. In order to build a database and estimate proper thicknesses of structure materials, this study used four structure materials that have been widely applied in naval ships such as AH36 steel, AL5083, AL5086, and Fiber Reinforced Plastics (FRP). A $7.62{\times}39mm$ mild steel core bullet normally fired by AK-47 gun was considered as a threat due to its representativeness. Tate and Alekseevskii's penetration algorithm was also used to calculate a correction factor (${\alpha}$) and then estimate the armor thickness of naval ship hull structure materials with a given impact velocity. Through live fire experiments, the proposed method performance difference was measured to be 0.6% in AH36, 0.4% in AL5083, 0.0% in AL5086, and 8.0% in FRP compared with the experiment results.