• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.2
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• pp.268-277
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• 1998

The numerical procedure for calculating non-uniform residual stress fields by using relieved strain data from incremental hole drilling method is presented. Finite element calculations are described to evaluate the relieved coefficients required for the determination of residual stresses. From the results of simulations it is found that this numerical method is well adopted to measuring non-uniform residual stress in the hole depth range of 0.8 times of the hole diameter from the surface. In order to examine the practicability of this method, the hole drilling procedure for the four point bending test is performed. This method is applied to the measurement of residual stresses in the cold-rolled steel pipe. It is shown that the magnitude of residual stress in the pipe is not negligible when compared with yield stress and the residual stress should be duly considered in designing structures with this pipes.

• Transactions of Materials Processing
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• v.14 no.8 s.80
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• pp.704-711
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• 2005

The influence of process parameters in drawn wire on residual stresses was investigated. Based on a FE-simulation of the wire drawing process, the effects of process parameters such as semi-die angle, reduction, friction coefficient and bearing length on the residual stresses were investigated. The validity of the FE-simulation results was verified by the comparison of the previous simulated results with experimental data. In this study, semi-die angle and die reduction have significant effect on the residual stresses at the surface of drawn wire. Several methods such as, addition of axial tension, application of skin pass, straightening in multi-roll straightener etc, were suggested in the previous studies to reduce the residual stresses. In this study, the results show that the concurrent application of skin pass with low die reduction and low semi-die angle at the final stage of drawing operation reduces dramatically the both axial and hoop residual stresses after drawing

• Journal of the Korean Society of Safety
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• v.9 no.3
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• pp.13-21
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• 1994

Effects of tensile and compression residual stresses in the welded SS41 and A17075-76 on fatigue crack propagation behavior are investigated when a crack propagates from residual stresses region. We propose the fatigue crack growth equation on tensile and compression residual stresses in welded metal. The results obtained in this experimental study are summarized as follows . 1 ) A fatigue crack growth equation which applied fatigue fracture behavior of the welded metal is proposed. (equation omitted) where, $\alpha$, $\beta$, ${\gamma}$ and $\delta$ are constants, and R$_{eff}$ is effective stress ratio [R$_{eff}$=(Kmin+Kres)/(Kmax+Kres)], Kcf is critical fatigue stress intensity factor. The constants are obtained from nonlinear least square method. The relation between crack length and number of cycles obtained by integrating the fatigue crack growth rate equation is in agreement with the experimental data. 2) The experimental results confirmed that the cause of crack extension and retardation by residual stresses has relation to the phenomenon of crack closure. 3) The relaxing trend of residual stresses by the crack propagation was greater In case of compressive residual stress than that of tensile residual stress in the welded metal.tal.

• The Journal of Korean Medicine
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• v.20 no.1 s.37
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• pp.44-51
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• 1999

Analysis of residual pesticides in herbal drugs was performed by GC-ECD and GC-MS. Especially, selected ion monitoring(SIM) technique was applied to increase the GC/MS sensitivity. Analysis of residual pesticides was determined sensitivity and selectively without any internal standard by setting the SIM technique to their characteristic fragments for quantitation ion and confirmation ion. The combination of two detector, GC-ECD and MS-SIM technique, is abailable for determining a multiclass residual pesticides in herbal drugs. The average recoveries through the method were $65.9%{\sim}99.7%$ in herbal drugs. The data of gas chromatographic analysis was compared with the limits of residual pesticides in herbal drugs and agricultural foods. 4. 4-DDT was detected above the limits to the residual pesticides in herbal drugs. Diazinon and EPN were detected, but the limits of residual pesticides were less than that of agricultural foods.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.19 no.2
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• pp.130-139
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• 2023

This paper examines the quantification of uncertainty for welding residual stresses in dissimilar metal welds used in nuclear power plants. A mock-up of a dissimilar metal weld pipe, consisting of carbon and stainless steel pipes, was fabricated to measure the residual stress. A Round-Robin analysis was conducted by Korean institutions to assess the welding residual stress. The analysis was carried out in the second order, and the data obtained by each institution was evaluated based on the information provided. Using the Round-Robin results, the distribution of uncertainty in welding residual stresses among Korean institutions was evaluated. The quantification of uncertainty for Korean institutions was found to have a wider range compared to the distribution of welding residual stresses observed in overseas institutions. This study is considered useful in the establishment of comprehensive strategies for evaluating welding residual stress analysis methods used by domestic institutions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.375-384
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• 2016

In this paper, when stereo image, satellite view and corresponding depth maps were used as the input data, we propose a new method that convert these data to data format suitable for compressing, and then by using these format, intermediate view is synthesized. In the transmitter depth maps are merged to a global depth map and satellite view are converted to residual image corresponding hole region as out of frame area and occlusion region. And these images subsampled to reduce a mount of data and stereo image of main view are encoded by HEVC codec and transmitted. In the receiver intermediate views between stereo image and between stereo image and bit-rate are synthesized using decoded global depth map, residual images and stereo image. Through experiments, we confirm good quality of intermediate views synthesized by proposed format subjectively and objectively in comparison to intermediate views synthesized by MVD format versus total bit-rate.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.6
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• pp.453-479
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• 2011

Residual pharmaceutical compounds have been recognized as emerging environmental pollutants and are widely distributed all over the world. These compounds cause bioaccumulation and biomagnification during present for a long time in the environment: thereby after adversely biota and human bodies. It is difficult to remove residual pharmaceutical compounds using conventional water/wastewater treatment because of resistant property to photodegradation, biodegradation and chemical decomposition. Moreover, domestic literature data on the pollution of residual pharmaceutical compounds in rivers and lakes are limited. In this paper, species, sources, fate and risk of residual pharmaceutical compounds as well as behavior properties in freshwater resources are demonstrated to encourage the domestic concern about residual pharmaceutical compounds. An extensive review of existing data in the form of figures and tables, encompassing many therapeutic classes are presented.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.4
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• pp.534-545
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• 2011

This paper describes the evaluation of kinetic parameters for pyrolysis and carbon char oxidation of residual oil. The non-isothermal pyrolysis of residual oil was carried out with TGA (Thermo-Gravimetric Analyzer) at heating rate of 2, 5, 10 and $20^{\circ}C/min$ up to $800^{\circ}C$ under N2 atmosphere. The first order and nth order pyrolysis models were used to fit the experimental data, and the nth order model was turned out to follow the experimental data more precisely than the first order model. For carbon char oxidation experiment, TGA and four heating rates used in pyrolysis experiment were also adapted. The kinetic parameters for the residual carbon char particle were obtained with three char oxidation model, that is, volume reaction, grain and random pore model. Among them, the random pore model described the char oxidation behaviour quite well, compared to other two models. The non-linear regression method was used to obtain kinetic parameters for both pyrolysis and carbon char oxidation of residual oil.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1317-1323
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• 2010

In this study, the weld residual stress distribution at a dissimilar-metal welded plate of low alloy carbon steel and stainless steel, which are widely used in nuclear power plants, was characterized. A plate mock-up with butt welding was fabricated using SA 508 low alloy steel and Type 304 stainless steel plates and the residual stresses were measured by the X-ray diffraction method after electrolytic polishing of the plate specimen. Finite element analysis was carried out in order to simulate the butt welding of dissimilar metal plate, and the calculated weld residual stress distribution was compared with that obtained from the measured data. The characteristics of the three-dimensional residual stress distribution in a butt weld of dissimilar metal plates were investigated by comparing the measured and calculated residual stress data.

• Journal of Environmental Science International
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• v.11 no.1
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• pp.41-56
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• 2002

In order to estimate the quantitative roles of the tide induced residual currents, density currents and wind driven currents on the residual currents in Kwangynag Bay Korea, numerical experiments with a diagnostic multi-level model were carried out. Density currents were calculated from the temperature and salinity data observed in January, May, August and November 1998. Anti-clockwise circulations are formed at the western inner part of the bay, the location from the east of Myodo Is. to the south of POSCO Co. and the place between Yeosu peninsula and Namhae Is. from the calculation results of the tide induced residual currents. Velocities of the density currents are less than 3cm/s at the western inner part of the bay and about 5cm/s at the southern entrance of the bay. Density currents get strong in summer and weak in autumn. Wind driven currents at the surface layer flow in the directions of the given winds which are the daily mean winds when the temperature and salinity observations are carried out. In the middle and lower layers, however the wind driven currents flow in the opposite direction to the surface currents as supplementary currents. The surface wind driven currents are greater than the tide induced residual currents or the density currents. The calculated residual currents including the tide induced residual currents, density currents and wind driven currents agree with the results of the current observations approximately. In the Bay, the wind driven currents affect on the residual currents greatestly and tide induced residual currents and density currents do in the second place and the third place.