• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.2
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• pp.149-154
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• 2012

The size and distribution of welding residual stress and welding deformation in welding structures have an effect on various sorts of damage like brittle failure, fatigue failure and stress corrosion cracking. So, research for this problem is necessary continuously. In this study, non-destructive technique using laser electronic speckle pattern interferometry, plate of welding specimen according to the external load on the entire behavior of residual stress are presented measurement techniques. Once, welding specimen force tensile loading, using electronic speckle pattern interferometry is measured. welding specimen of base metal and weld zone measure strain from measured result, this using measure elastic modulus. In this study, electronic speckle pattern interferometry use weld zone and base metal parts of the strain differences using were presented in residual stress calculated value, This residual stress value were calculated by numerical calculation. Consequently, weld zone of modulus high approximately 3.7 fold beside base metal and this measured approximately 8.46 MPa.

• Journal of Navigation and Port Research
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• v.27 no.5
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• pp.519-526
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• 2003

For preliminary structural analysis of superstructures on very large floating structures(VLFS), superstructures are analyzed considering elastic deformations of barge type lower-structures subjected to wave loads. In this case, to consider the effect of wave loads on the superstructure, initial displacements at the support points of superstructures are evaluated as input data for the analysis. However, the evaluation and application of displacement loads are tedious and very time-consuming processes. Therefore, this paper proposes a simplified static analysis method to analyze the structural behaviors of superstructures on very large floating structures subjected to wave loads. In this study, the member forces due to the variation of beam span and the amplitude and period of wave load are analyzed by using an example 4 span -3 story structure and the amplification factors for beam moments are represented by the specific regression equation.

• Journal of the Korean Chemical Society
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• v.28 no.4
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• pp.205-209
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• 1984

The crystal and molecular structure of thiosinamine, $H_2NCSNHCH_2CHCH_2$, has been determined by X-ray diffraction method. The crystals are monoclinic, space group $P2_1/a$ with four molecules in a unit cell of dimensions, a = 9.819(3), b = 8.553(3), c = 9.170(2)${\AA}$, ${\beta}$ = 127.3(1)$^{\circ}$, and z = 4. Intensity data for 814 reflections were collected with a Rigaku-Denki automatic four circle diffractometer. The structure was solved by direct and Fourier methods. Refinements were carried out by full matrix least-squares method to a final R value of 0.046. The thiourea unit is planar, and the bond lengths and angles in that unit agree well with those in the compounds which contain a thiourea moiety. The molecules are linked together by the two patterns of N-H${\cdots}$S hydrogen bonds along the b-axis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.4
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• pp.133-140
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• 2008

The design method of the reinforced concrete structures is converting from the current limit state design method to the reliability based design method and active studies have been done in the US, Europe, and Japan etc. Performance based design method is considering lots of uncertainty of current design provision rationally and make sure that structure have a reliable reliability and safety. The main area of these studies is to secure the non-linear analysis technology with high reliability. The data for reinforced concrete columns tested by many researchers are used to verify the applicability of the nonlinear finite element analysis program (RCAHEST, Reinforced Concrete Analysis in Higher Evaluation System Technology). A comparison is made between analysis and test, calculated safety factor based on reliability theories to applies to analysis result.

• Korean Journal of Crystallography
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• v.7 no.2
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• pp.126-132
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• 1996

Cholesteryl isopropyl carbonate(C31O3H52) is orthorhombic, space group P212121, a=6.266(4), b=10.836(5), c=47.364(20)Å, Z=4, Dc=0.98 g/cm3 and Dm=1.01 g/cm3. The intensity data were collected on a Nonius CAD-4 diffractometer with a graphite-monochromatized MoKα radiation to a maximum 2θ value of 40°. The structure are solved by direct methods and refined by Fourier and full matrix least-squares methods. The present R factor was 0.22 for 1513 observed reflections. The further refinements are in progress. Compared with other cholesterol derivatives, the cholesteryl ring and tail region of the molecule are normal. The molecular long axes are parellel to the c-axis. There are close packings of cholesterol groups and loose packings of isopropyl carbonate chains forming monolayers.

• The Journal of Engineering Geology
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• v.21 no.1
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• pp.57-64
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• 2011

Three-dimensional slope stability analysis was applied to a failed dual-lithology slope containing both granite and an andesitic dyke, taking account of the differences in shear strength of the different lithologies. A direct shear test of the soil-rock boundary was performed to examine the shear strength of two different types of failure surfaces within different lithologies, and a laboratory test was performed on an upper, weathered soil layer. The test results indicate that shear strength was lower at the soil-rock boundary than within the weathered soil layer. A representative geological section was subjected to two-dimensional slope stability analysis using a limit equilibrium method to assess whether the distribution of lithologies upon the slope influences the results of stability analysis. The results were then compared with those of three-dimensional slope stability analysis, for which input parameters can be varied according to the distribution of lithologies upon the slope. The three-dimensional analysis yielded safety factors of 1.26 under dry conditions and 0.55 under wet conditions, whereas the two-dimensional analysis yielded unstable safety factors of 0.92 and 0.32, respectively. These findings show that the results of stability analysis are affected by the distribution of different lithologies upon the slope. Given that the studied slope collapsed immediately after rainfall, it is likely that the results of the three-dimensional analysis are more reliable.

• Journal of the Korean Geotechnical Society
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• v.37 no.11
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• pp.23-36
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• 2021

In this paper, the effect of shear rate on internal friction angle and unconfined compressive strength of non-cemented and cemented sand was investigated. A dry Jumunjin sand was prepared at loose, medium, and dense conditions with a relative density of 40, 60 and 80%. Then, series of direct shear tests were conducted at shear rates of 0.32, 0.64, and 2.54 mm/min. In addition, a cemented sand with cement ratio of 8% and 12% was compacted into a cylindrical specimen with 50 mm in diameter and 100 mm in height. Unconfined compression tests on the cemented sand were performed with various shear rates such as 0.1, 0.5, 1, 5 and 10%/min. Regardless of a degree of cementation, the unconfined compressive strength of the cemented sand and the angle of internal friction of the non-cemented sand tended to increase as the shear rate increased. For the non-cemented sand, the angle of internal friction increased by 4° at maximum as the shear rate increased. The unconfined compressive strength of the cemented sand also increased as the shear rate increased. However, its increasing pattern declined after the standard shear rate (1 mm/min). A discrete element method was also used to analyze the crack initiation and its development for the cemented sand with shear rate. Numerical results of unconfined compressive strength and failure pattern were similar to the experimental results.

• Food Science and Industry
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• v.52 no.1
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• pp.40-51
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• 2019

For better understanding the relationship between consumers' perception and sensory characteristics of products, diverse types of rapid sensory profiling technique have been suggested as alternatives to conventional descriptive analysis. Among these, check-all-that-apply (CATA) method has gained popularity for studying consumers' perception and intuitive responses to products due to their simplicity, speed, and ease of use. CATA method has been used to gather consumers' perception derived from sensory characteristics of products as well as consumers' emotion responses to products in recent years. Moreover, many researchers reported that CATA method can be used to provide valuable information for product optimization by applying a penalty analysis and collecting responses to ideal product. Thus, this article reviews recent research using CATA in the field of sensory and consumer science and introduces practical applications to achieve various business objectives in food industry.

• Journal of the Korea Institute of Building Construction
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• v.11 no.3
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• pp.229-237
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• 2011

The pullout test is a nondestructive testing method certified by the American Society for Testing and Materials (ASTM) and British Standards (BS). Research has shown that it is very reliable in terms of evaluating the concrete strength of reinforced concrete members. However, the pullout test is rarely performed on domestic construction sites due to the complex procedures and high costs involved. This study proposes a new pullout test composed of a post installable break-off bolt, an insert nut, and a pullout tester, which satisfy both economical and practical purposes on a construction site. Three different types of special fastening methods, a temporary fixed bolt, a plastic fixed panel, and a fixed bar, have been developed. A pullout tester is proposed that is driven by the circle force introduced into a handle composed of eight gears without a load cell and a hydraulic cylinder. The serviceability and reliability of these instruments were investigated through experiments at construction sites. Furthermore, the sample pullout test with a wall specimen was conducted to estimate the usefulness of the temporary fixed bolt type of fastening methods and pullout devices. Eventually, the developed instruments will be useful on construction sites if minor requirements are met.

• Journal of the Korean Geosynthetics Society
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• v.3 no.4
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• pp.41-48
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• 2004

Recently a method for increasing the bearing capacity by laying the reinforcing materials with three or four layers as a method reinforcing the ground was studied recently. The purpose of this study is to examine the method for increasing shear-strength factor of the ground by reinforcing the ground under the foundation. According a method of wrapping ground with bakk-shape or semicircle-shape by geotextile was developed in this study and it looks likes anaspect that spreading footing exits under spread footing. A simulation loading-test using Aluminum sticks was carried out in order to examine the mechanism about bearing capacity of spread footing reinforced by geotextile. Increase of ultimate bearing capacity was verified in this simulation loading-test when charging loads to spread footing, which is propose from this study, reinforced by geotextile. And moving directions of points of the ground were also checked by grid-type indication method, and the areas where plastic failure appeared were checked by B-shutter photographing.