• Journal of the Korea Institute of Building Construction
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• v.20 no.5
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• pp.449-457
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• 2020

Due to the improvement of living standards and avoidance of the 3D industry, it is difficult to find young and competent domestic workers at construction sites, and most foreign workers are contributing to the replacement, but the quality is still deteriorating due to lack of skilled workers and aging. Precast method is a method that make members in factory and assembles them on site, which can be expected to improve labor force and quality. This study is intended to provide basic data for the development of hang-type PC beams that can be applied to the determination of the field application of developed PC beams. The U-type connecting material is installed on both ends of the hang-up PC beam, and the role of the U-type connecting material is very important because it is a simple construction method through the U-type connecting material. In addition, the performance of the U-type connecting material will determine the performance of the hang-type PC beam as the final destruction occurs in the hang-type PC beam. The material properties of U-type connecting material were identified through structural experiments, and the end test corresponding to the partial experiment was conducted based on the material test results identified. Finally, the final design value of PC beams was proposed through structural experiments for application to the site.

• Korean Journal of Construction Engineering and Management
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• v.10 no.5
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• pp.123-134
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• 2009

Since 1970s, urethane waterproofing method is broadly used in rooftops, underground spaces, and sports stadium for its outstanding ultraviolet blockage, watertightness, and elasticity. However, development of slippage-resistance and endurance, improvement of function considering convenience and visually pleasing of users, urethane waterproofing method is necessary, since rooftops and underground spaces have slippage and external force risks. Therefore, many improved waterproofing methods are being developed and, recently, embo-thane waterproofing method, which applies embo-spray coating system, has been developed. This paper explains exposure, nonexposure, and floor-material of embo-thane waterproofing method, and then perform experimental study for comparison with urethane waterproofing method about tensile strength, coefficient of expansion, performance of bond, anti-abrasion, and slippage-resistance. In addition, the performance index was presented for the superiority of embo-thane waterproofing method compared to urethane by setting up evaluation criteria considering not only physical performance but also design side of embo-thane waterproofing method, and Value Analysis applying AHP. Also for an assessment considering uncertain result, Monte Carlo Simulation Method was used to operate reliability analysis through statistic approach method.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.3
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• pp.415-430
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• 1996

The purpose of this study was to evaluate the stress distributions in the surrounding tissues of the teeth seated by indirect retainers in three different teeth of unilateral distal extension partial denture when the dislodging forces were applied on denture bases. Three dimensional photoelastic models were made. The teeth on which indirect retainers were seated were mandibular left lateral incisor (Model I), canine (Model II), and first premolar (Model III). The dislodging force with 860mg at $45^{\circ}$ angulation to occlusal plane was applied to each model. Three dimensional photoelastic stress analysis was done, and the records were diagramed and analysed. The results were as follows : The compressive stresses were shown the most on neck portions of buccal, mesial, and distal sides in all three models. Slight tensile stresses were shown on neck portions of lingual sides in all three models. The compressive stresses on buccal side were shown in strength in such order as model I, model II, and model III. The compressive stresses were shown on neck portion of mesial and distal sides of model I and mode II, with model I more than Model II. The compressive stresses were shown only on neck portion of mesial side on Model III. The general overall magnitude of compressive stresses were shown in strength in such order as Model I, Model II, and Model III.

• International journal of advanced smart convergence
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• v.10 no.4
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• pp.241-255
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• 2021

The human auricle is the first part to receive sound from the outside. In this part, the frequency range of human recognizable form is divided and organized. In this study, we propose modeling by applying a single sound source to the surface of the human auricle. This means that when the sound pressure of a low frequency (low frequency) sound enters the pinna, the impedance felt at the tip of a part of the non-linear surface of the pinna is mainly due to the tensile force at the end of the part of the non-linear surface of the pinna. By expressing the situation of moving at a very small speed, the characteristic impedance of the pinna was confirmed to be negative infinity, and it was also confirmed that the speed at the tip of a part of the non-linear surface of the pinna was 0 in the anti-resonance state. It was found that the wave propagation phenomenon that determines the characteristics of the filter is determined by how large the wavelength, kL, is compared to the length of the tip of a part of the non-straight surface of the pinna. Humans first receive sounds from outside through their ears. The auricle is non-linear and has a curved shape, and it is known that it analyzes frequencies while receiving external sounds. The human ear has an audible frequency range of 20Hz - 20,000Hz. Through the study, we applied the characteristics of the notch filter to hypothesize that the human audible frequency range is separated from the auricle, and applied filter theory to analyze it, and as a result, meaningful results were obtained. The curved part and the inner part of the auricle function as a trumpet, collecting sounds, and at the same time amplifying the weak sound of a specific band. The point was found and the shape of the envelope detected in the auricle was found. Selectivity for selecting sounds coming from the outside is the formula of the pinna that implements the function of Q. The function of distinguishing human-recognizable sound from the pinna from low to high through frequency analysis is performed in the pinna, and the 2-3kHz area, where human hearing threshold is the most sensitive, is also the acoustic impedance of the most recessed area of the pinna. It can be seen that starting from.

• Journal of the Society of Disaster Information
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• v.16 no.4
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• pp.796-805
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• 2020

Purpose: A static loading test was performed to evaluate the ultimate flexural strength of a girder in which 80MPa high-strength concrete was synthesized on the compressive flange of the I-shape steel girder. Method: This test is designed and fabricated two types of specimens with different shear-connection specifications, and evaluated their ultimate flexural behavior until reaching the extreme event limit states. In addition, the ultimate strength was evaluated by comparing the test results and the results of the strain compatibility method. Result: By confirming the displacement within 0.02mm as a result of the relative slip measurement, it was verified that the two specimens secured perfect bonding. Therefore, the difference in the shear specification does not have a great effect on the stiffness, and if the specimens are completely synthesized, there is no difference in the behavior until it reaches the extreme-event limit states. Conclusion: The girder to be tested has a working load within the elastic range and meets the usability requirements for allowable deflection. Therefore, even if a part of the casing is subjected to the tensile force at the level of cracking, the deck will first reach the compression failure due to the role of the reinforcing bar.

• Journal of the Korea Institute of Building Construction
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• v.22 no.1
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• pp.11-21
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• 2022

Currently, in the domestic construction industry, the free web method has been emerging as a potential solution to the shortage of skilled workers due to the prolonged COVID-19 crisis, as it helps in securing economic feasibility through shortening the construction period and reducing labor costs. To consider one part of the construction method, in this study, the bending behavior according to the load was evaluated for the SY slope-type beam formwork, which was manufactured at a factory, assembled with rebar, brought into the site, and then poured into the site. For the SY Beam standard cross-sectional shape, a cross-sectional dimensional width of 400mm and depth 600mm determined through structural modeling using the MIDAS GEN program were applied. A total of 6 specimens were made with a member length of 5,000mm, 5 specimens and one RC specimen in the comparison group were manufactured in real-size format using the thickness of the steel plate(0.8, 1.0, 1.2mm) as a variable, and bending experiments were performed. In the bending test, the steel plate deck showed high initial stiffness and maximum strength as it yielded, which showed that it sufficiently contributed to the flexural strength. It is judged that additional analysis and experimental studies for 1.05, 1.1, and 1.15mm are needed to derive the appropriate steel plate thickness and the method for calculating the tensile force contribution of the steel plate to secure the manufacturing, construction and economic feasibility of SY Beam in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1A
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• pp.1-13
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• 2010

This paper presents an investigation on the geometric nonlinear behavior of cable-stayed bridges using geometric nonlinear finite element analysis method. The girder and mast in cable-stayed bridges show the combined axial load and bending moment interaction due to horizontal and vertical forces of inclined cable. So these members are considered as beam-column member. In this study, the nonlinear finite element analysis method is used to resolve the geometric nonlinear behavior of cable-stayed bridges in consideration of beam-column effect, large displacement effect (known as P-${\delta}$ effect) and cable sag effect. To analyze a cable-stayed bridge model, nonlinear 6-degree of freedom frame element and nonlinear 3-degree of freedom equivalent truss element is used. To resolve the geometric nonlinear behavior for various live load cases, the initial shape analysis is performed for considering dead load before live load analysis. Then the geometric nonlinear analysis for each live load case is performed. The deformed shapes of each model, load-displacement curves of each point and load-tensile force curves for each cable are presented for quantitative study of geometric nonlinear behavior of cable-stayed bridges.

• Progress in Superconductivity and Cryogenics
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• v.25 no.4
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• pp.19-23
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• 2023

The Second-generation high-temperature superconducting (HTS) Rare-Earth Barium Copper Oxide (REBCO) wire is a composite laminate having a multi-layer structure (8 or more layers). HTS wires will undergo multiple loads including the bending-tension loads during winding, high current density, and high magnetic fields. In particular, the wires are subjected to bending stress and magnetic field stress because HTS wires are wound around a circular bobbin when making a high-field magnetic. Each of the different laminated wires inevitably exhibits damage and fracture behavior of wire due to stress deformation, mismatches in thermal, physical, electrical, and magnetic properties. Therefore, when manufacturing high-field magnets and other applications, it is necessary to calculate the stress-strain experienced by high-temperature superconducting wire to present stable operating conditions in the product's use environment. In this study, the finite element model (FEM) was used to simulate the strain-stress characteristics of the HTS wire under high current density and magnetic field, and bending loads. In addition, the result of obtaining the neutral axis of the wire and the simulation result was compared with the theoretical calculation value and reviewed. As a result of the simulation using COMSOL Multiphysics, when a current of 100 A was applied to the wire, the current value showed the difference of 10^-9. The stress received by the wire was 501.9 MPa, which showed a theoretically calculated value of 500 MPa and difference of 0.38% between simulation and theoretical method. In addition, the displacement resulted is 30.0012 ㎛, which is very similar to the theoretically calculated value of 30 ㎛. Later, the amount of bending stress by the circular mandrel was received for each layer and the difference with the theoretically obtained the neutral axis result was compared and reviewed. This result will be used as basic data for manufacturing high-field magnets because it can be expanded and analyzed even in the case of wire with magnetic flux pinning.

• Journal of Life Science
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• v.26 no.11
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• pp.1275-1281
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• 2016

The principal objective of this fundamental research was to analyze the physicochemical properties the and antioxidative activity of Napa cabbage pickle (NCP) for development of low-salt pickles. NCP-1 was a smaller than NCP at amount soy sauce (10%). The pH of NCP and NCP-1 were $4.51{\pm}0.15$, $4.85{\pm}0.08$ immediately after preparation. The pH of NCP and NCP-1 was reduced to $4.08{\pm}0.05$ and $4.31{\pm}0.12$ over time during 60 days of storage. The acidity of the NCP and NCP-1 immediately after preparation were 0.51% and 0.38% and increased to 0.67% and 0.56% after 60 days of storage. The salinity for the NCP ranged from 1.71-2.22% and NCP-1 ranged from 1.18-1.63%. The L value, which indicates the lightness, was the highest at day 0 and the lowest at 60 day. The tensile strength value of NCP was $10.9{\pm}0.05kgf/cm^2$ and NCP-1 in $11.84{\pm}0.11kgf/cm^2$ at day 0 and then significantly decreased with time in storage. The cutting force of NCP was $1004{\pm}7.12gf/cm^2$ and NCP-1 in $845{\pm}5.27gf/cm^2$ at day 0, which increased over time in storage. The overall acceptability of NCP was the highest at day 30, but the overall acceptability of NCP-1 was the highest at day 45. NCP-1 extracts at day 60 showed the highest antioxidant activity of 66.04%, whereas the NCP extract at day 0 showed the lowest antioxidant activity of 45.41%. These results showed that depending on the content of the seasoning pickle difference in the antioxidant activity. Thus, the best pickled Napa cabbage is determined by a smaller amount soy sauce in NCP-1, and the results could provide a basis for improving the availability and quality of Napa cabbage.

• Korean journal of food and cookery science
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• v.16 no.6
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• pp.593-601
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• 2000

Seven domestic wheat cultivars, Suwon 261, Suwon 265, Eunpa, Kobun, Alchan, Olgru, and Kumgang, and a standard wheat, ASW(Australian Standard White Wheat), were compared in noodle-making properties. The ash contents of domestic wheats and flours were 0.1-0.3% higher than that of ASW. Therefore, domestic wheats required the control of ash contents during milling process. The protein contents which suggest the flour gluten content were 10.32, 11.3, and 9.57% in Suwon 261, Suwon 265, and Kumgang cultivars, respectively. Valorimeter values of Eunpa, Olgru, and Kumgang which indicate the dough formation time and stability were similar to that of ASW. Resistance rate of domestic wheats was lower than that of ASW. Maximum viscosity in Amylograph for Eunpa, Olgru, and Kumgang were in the range of 500-800BU, which were suitable for making noodles. Increase in weight and volume of Olgru noodle was negatively correlated with protein content. Turbidity was not positively correlated with weight and volume increase, but domestic cultivars except Suwon 265 and Eunpa showed a similar turbidity with ASW. The mechanical properties of wet and dry noodles were evaluated by TPA test before and after cooking. Springiness and cohesiveness of wet noodles increased by cooking, and the domestic cultivars showed higher values than ASW. Springiness and cohesiveness of dry noodle were not increased by cooking in any cultivars. Gumminess, chewiness and hardness of domestic wheat cultivars showed higher values than that of ASW. In the tensile test, wet noodles showed no difference between domestic cultivars and ASW. But dry noodles of domestic wheat cultivars showed higher values than ASW. In the color test for lightness, redness and yellowness, there were no differences between flour and dough of domestic wheat cultivars and ASW. In the sensory evaluation, Kumgang wheat cultivar was the most preferred among the wet and dry noodles of other domestic wheat cultivars and ASW. These results suggested Kumgang wheat cultivar to be a practical wheat variety for noodle-making.