• Title/Summary/Keyword: laboratory experiments

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Recognition of General arts classes based on movie - Focused on the movie "Untouchables: 1% friendship" (영화 기반 교양교과 수업 활동 탐색 - 영화 「언터처블: 1%의 우정」 중심으로)

  • Kim, Seong-Won;Youn, Jeong-Jin
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.7 no.6
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    • pp.63-72
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    • 2017
  • This study made of centrally actual application in general arts classes based on movie in university. Especially, I analyzed the activities of the class with 'Untouchable: 1% friendship' among 6 films. The objects of this study are 44 students of D university in Busan Metropolitan City who take 'creative fusion from movie' general arts class which opened first semester in 2016. In this study, students were able to watch movies through the creative class, which was out of the traditional classroom method, and after 15 hours of learning the quiz online, they conducted 15 weeks as a teaching method to perform tasks, presentations, experiments, and experiences in regular class time. The results of this study are as follows. 'It is a general arts class that makes movements live,' 'It is a general arts class that shows movies from various perspectives,' and 'It is a general arts class that makes me know.' This suggests that the educational medium, which is easily accessible in everyday life, and the general arts class, which is active in the space outside the framework, are perceived as stimulating curiosity and adding fun to college students.

Characteristics of Water Level and Velocity Changes due to the Propagation of Bore (단파의 전파에 따른 수위 및 유속변화의 특성에 관한 연구)

  • Lee, Kwang Ho;Kim, Do Sam;Yeh, Harry
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.5B
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    • pp.575-589
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    • 2008
  • In the present work, we investigate the hydrodynamic behavior of a turbulent bore, such as tsunami bore and tidal bore, generated by the removal of a gate with water impounded on one side. The bore generation system is similar to that used in a general dam-break problem. In order to the numerical simulation of the formation and propagation of a bore, we consider the incompressible flows of two immiscible fluids, liquid and gas, governed by the Navier-Stokes equations. The interface tracking between two fluids is achieved by the volume-of-fluid (VOF) technique and the M-type cubic interpolated propagation (MCIP) scheme is used to solve the Navier-Stokes equations. The MCIP method is a low diffusive and stable scheme and is generally extended the original one-dimensional CIP to higher dimensions, using a fractional step technique. Further, large eddy simulation (LES) closure scheme, a cost-effective approach to turbulence simulation, is used to predict the evolution of quantities associated with turbulence. In order to verify the applicability of the developed numerical model to the bore simulation, laboratory experiments are performed in a wave tank. Comparisons are made between the numerical results by the present model and the experimental data and good agreement is achieved.

Evaluation of Cavity Characterization Using Infrared Thermal Images (적외선 이미지를 이용한 지하공동 평가)

  • Jang, Byeong-Su;Kim, Young-Seok;Kim, Se-Won ;Choi, Hyun-Jun;Yoon, Hyung-Koo
    • Journal of the Korean Geotechnical Society
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    • v.39 no.7
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    • pp.69-76
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    • 2023
  • Cavity causes settlement and its remediation after an accident results in significant time and economic losses. This study aims to experimentally evaluate the prospect of using infrared camera to detect and measure underground subsidence. Emissivity is necessary to detect the energy emitted from an object and accurately assess temperature using an infrared camera. The emissivity in laboratory tests is fixed to evaluate a reasonable distance between the infrared camera and the object, and temperature values are assessed at various distances. In field experiments, the cavity of the field experiment is simulated using a PVC pipe with a diameter of 5 cm, artificially buried at depths of 5 and 25 cm from the surface. The infrared camera measurements are taken from 4 PM to 3 PM of the next day (a total of 23 h). The analysis included the time-series temperature distribution and the cooling rate index assessment, which represents the temperature change rate per unit of time. The results showed that various temperature trends are observed depending on the location of the subsidence. This study demonstrates that the infrared camera can be used to assess the condition of the subsurface.

Revision of Repair Materials Performance Requirement for Concrete Structures (콘크리트 구조물 단면복구공사 보수재료 품질기준개선)

  • Lee, Il Keun;Kim, Ki Hwan;Kim, Hong Sam;Yun, Sung Hwan;Kim, Woo Seok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.43 no.1
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    • pp.9-20
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    • 2023
  • For highway concrete structures, the deterioration of the structure is accelerated due to the increase in the use of deicing materials, and sectional repair work is being frequently carried out to restore performance. However, after the repair work, re-damage such as cracks, delamination, and poor bond performance is exhibited in the repaired sectional area. In this study, overseas repair material requirements were first analyzed, and present domestic requirements were improved repair material performance through field surveys of common concrete structures, laboratory experiments, and test construction on a disused concrete bridge. In addition, performancebased quality requirements were presented so that all materials that meet the required performance can be applied, and different test methods for each material were unified into concrete test methods for consistent test results analysis. The considered performance requirements were compression strength, bending strength, and bond strength for structural properties, and length change rate, crack resistance, thermal expansion coefficient, and elasticity coefficient were for dimensional behavior. For resistance to chloride penetration resistance and freeze-thaw resistance were presented as durability. The proposed requirements for concrete repair materials are expected to contribute to the improvement of the quality of concrete sectional repair work in Korea.

Flow Structure and Turbulence Characteristics in Meandering Channel (사행수로의 흐름구조 및 난류특성)

  • Seo, Il Won;Lee, Kyu Whan;Baek, Kyong Oh
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.5B
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    • pp.469-479
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    • 2006
  • In order to investigate characteristics of the primary flow and the secondary currents in meandering channels, the laboratory experiments were conducted in S-curved channels with angle of bend, $150^{\circ}$, and sinuosity of 1.52. The experimental conditions was decided varying average depth and velocity. Under these experimental conditions, spatial variations of the secondary currents in multiple bends were observed. The experimental results revealed that the distribution of primary flow in straight section is symmetric without respect to the experimental condition and the maximum velocity line of the primary flow occurs along the shortest path in experimental channel, supporting the result of previous works. The secondary currents in second bend became more developed than those in first bend. Particularly, the outer bank cell developed distinctively and the secondary current intensity was low at the straight section and high at the bends, periodically. Also, the secondary current intensity at the bends was as twice to three times as that at the straight section, and has its maximum value at the second bend. The turbulent flow characteristics of meandering channel was investigated with turbulent intensity of the primary flow and Reynolds shear stress. It was observed that the turbulent intensity is increasing when the velocity deviation of the primary flow is large whereas Reynolds shear stress increases when both the velocity deviation of the primary flow and the secondary current are large.

Effects of Velocity Structures on Tracer Mixing in a Meandering Channel (사행수로에서 유속구조가 추적물질의 혼합에 미치는 영향)

  • Seo, Il Won;Park, Sung Won
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.1B
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    • pp.35-45
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    • 2009
  • In this study, a laboratory experiment has been performed on a S-curved channel with two curved sections. In the experiments, effects of 3-D velocity structures on mixing characteristics of tracer material were investigated. As a result, it was clearly noticed that the primary flow travels taking the shortest course of the meandering channel and has a very ununiform distribution at the bends. The secondary cell which was developing at the first bend disappears at the crossover, and then, at the next bend, secondary cell is re-developing in the opposite direction. The experimental results show that mixing of tracer is significantly affected by the combined action of ununiform primary flow and secondary cell. The ununiform primary flow separates the tracer cloud in the longitudinal direction, and the secondary cell further separates the retarding tracer cloud mainly in the transverse direction. As a result, these complex flow structures cause separation and spreading of tracer cloud both in the longitudinal and in the transverse directions. The measured dimensionless transverse dispersion coefficients calculated using 2-D routing procedure ranges 0.012-0.875, and is generally proportional to width to depth ratio (W/h). The predicted values calculated by the theoretical equation overestimate slightly the measured transverse dispersion coefficients.

Numerical Analysis of Wave Transformation of Bore in 2-Dimensional Water Channel and Resultant Wave Loads Acting on 2-Dimensional Vertical Structure (2차원수조내에서 단파의 변형과 구조물에 작용하는 단파파력에 관한 수치해석)

  • Lee, Kwang Ho;Kim, Chang Hoon;Kim, Do Sam;Hwang, Young Tae
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.5B
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    • pp.473-482
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    • 2009
  • This study numerically discusses wave forces acting on a vertical wall such as breakwaters or revetments, subjected to incident undular or turbulent bores. Due to the complex hydrodynamics of bore, its wave forces have been predicted, mainly through laboratory experiments. Numerical simulations in this paper were carried out by CADMAS-SURF(CDIT, 2001), which is based on Navier-Stokes momentum equations and VOF method (Hirt and Nichols, 1981) for tracking free water surface. Its original source code was also partly revised to generate bore in the numerical water channel. Numerical raw data computed by CADMAS-SURF included great strong spike phenomena that show the abrupt jumps of wave loads. To resolve this undesired noise of raw data, the band-pass filter with the frequency of 5Hz was utilized. The filtered results showed reasonable agreements with the experimental results performed by Matsutomi (1991) and Ramsden (1996). It was confirmed that CADMASSURF can be applied to the design of coastal structures against tsunami bores. In addition, the transformation process and propagation speed of bores in the same 2-d water channel were discussed by the variations of water level for time and space. The numerical results indicated that the propagation speed of bore was changed due to the nonlinear interactions between negative and reflected waves.

Three sesquiterpene lactones suppress lung adenocarcinoma by blocking TMEM16A-mediated Ca2+-activated Cl- channels

  • Ruilian Xiu;Jie Jia;Qing Zhang;Fengjiao Liu;Yaxin Jia;Yuanyuan Zhang;Beibei Song;Xiaodan Liu;Jingwei Chen;Dongyang Huang;Fan Zhang;Juanjuan Ma;Honglin Li;Xuan Zhang;Yunyun Geng
    • The Korean Journal of Physiology and Pharmacology
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    • v.27 no.6
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    • pp.521-531
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    • 2023
  • Transmembrane protein TMEM16A, which encodes calcium-activated chloride channel has been implicated in tumorigenesis. Overexpression of TMEM16A is associated with poor prognosis and low overall survival in multiple cancers including lung adenocarcinoma, making it a promising biomarker and therapeutic target. In this study, three structure-related sesquiterpene lactones (mecheliolide, costunolide and dehydrocostus lactone) were extracted from the traditional Chinese medicine Aucklandiae Radix and identified as novel TMEM16A inhibitors with comparable inhibitory effects. Their effects on the proliferation and migration of lung adenocarcinoma cells were examined. Whole-cell patch clamp experiments showed that these sesquiterpene lactones potently inhibited recombinant TMEM16A currents in a concentration-dependent manner. The half-maximal concentration (IC50) values for three tested sesquiterpene lactones were 29.9 ± 1.1 µM, 19.7 ± 0.4 µM, and 24.5 ± 2.1 µM, while the maximal effect (Emax) values were 100.0% ± 2.8%, 85.8% ± 0.9%, and 88.3% ± 4.6%, respectively. These sesquiterpene lactones also significantly inhibited the endogenous TMEM16A currents and proliferation, and migration of LA795 lung cancer cells. These results demonstrate that mecheliolide, costunolide and dehydrocostus lactone are novel TMEM16A inhibitors and potential candidates for lung adenocarcinoma therapy.

Research on simple measurement method of floor finishing materials to predict lightweight floor impact noise reduction performance in apartment houses (공동주택 경량 바닥충격음 저감성능 예측을 위한 바닥마감재 간이측정 방법 연구)

  • Min-Woo Kang;Yang-Ki Oh
    • The Journal of the Acoustical Society of Korea
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    • v.42 no.6
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    • pp.594-602
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    • 2023
  • To date, research on heavy floor impact noise has mainly been conducted. The reason is that in the case of lightweight floor impact noise, sufficient performance could be secured with only the floating floor structure and floor finishing materials. In the case of heavy floor impact noise in a floating floor structure, the reduction performance can be predicted to some extent by measuring the dynamic elasticity of the floor cushioning material. However, with the recent introduction of the post-measurement system, various floor structures are being developed. In particular, many non-floating floor structures that do not use cushioning materials are being developed. In floor structures where cushioning materials are not used, the finishing material will have a significant impact on lightweight floor impact noise. However, research on floor finishing materials is currently lacking. In this study, as a basic research on the development of various floor finishing materials for effective reduction of lightweight floor impact noise, various materials used as floor finishing materials for apartment complexes were selected, the sound insulation performance of lightweight floor impact noise was measured in an actual laboratory, and vibration characteristics were identified through simple experiments. The purpose was to confirm the predictability of light floor impact noise.

Particle Size Characteristics with the Specification of Yeongdong Illite Powder Products (영동 일라이트 분말 제품의 규격에 따른 입도 특성)

  • EunJi Baek;Yu Na Lee;Eun Jeong Kim;Youngseuk Keehm;Hyun Na Kim
    • Korean Journal of Mineralogy and Petrology
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    • v.36 no.4
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    • pp.345-353
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    • 2023
  • This study aimed to investigate the differences in the commercial powder products of the Yeongdong illite based on sales specifications, specifically examining the mineralogical composition, particle size, and chemical composition according to mesh size. The goal was to understand the characteristics of illite powder products and utilize them as a mineralogical database for exploring various applications. Commercial illite powder samples obtained from two mines were subjected to various experiments, including X-ray diffraction (XRD) analysis, laser diffraction particle size analysis, and scanning electron microscopy analysis, X-ray fluorescence analysis. The XRD analysis revealed that the illite powder products from the two mines mainly consisted of illite/muscovite, quartz, and feldspar, indicating similar constituent minerals matching with those of ores for each mine. Laser diffraction particle size analysis indicated the difference in particle size distribution depending on the product specifications, with particle size uniformity tending to increase with increasing mesh sizes. Scanning electron microscopy analysis showed variations in particle shape and size based on specifications. The size of illite particles did not vary significantly with product specifications, with noticeable changes observed mainly in the particle sizes of quartz and feldspar. Furthermore, although there were some differences in chemical composition among the samples from different mines, no significant variations were observed according to specifications. Based on these results, when considering the application of commercial illite powder, it is essential to carefully select it with the consideration of its specifications to account for characteristic variations. The findings of this study present support the great potential of various application fields of commercial illite powder, contributing to industrial utilization and the development of new technologies.