• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.1
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• pp.61-67
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• 2013

In this paper, it was studied how the critical speed which could occur hot judder due to disk temperature. Through the dynamometer experiment, we measured the critical velocity and surface temperature when the hot judder occur on the disk break. Also with the critical velocity theory equation and the temperature change graph of factors which used in the equation, we was induced experiment equation including theory equation and experiment values. And it has compared with the method which approach as linea. From this, we predicted the change of critical speed which could occur hot judder due to disk temperature. In addition, critical speed graph has compared with actual driving speed and disc temperature at a vehicle test. Therefore it was estimate to possibility of arising hot judder.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8568-8575
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• 2015

This study, as a experiment study, was intended to determine whether or not the situational leadership program was highly helpful to critical thinking, coaching, empowerment-enhancing of nurse managers. The number of subjects was abstracted by G*Power, and 54 nurses leader and 342 general nurses were selected from university hospitals of metropolitan city. Data analysis was frequency analysis, t-test, $X^2$-test, repeated measures ANOVA, using SPSS Win 18.0 statistical package program. The results of this study was as follows. 1. Due to the situation leadership programs, critical thinking of experiment group has significantly increased, but control group was significantly reduced. 2. Due to the situation leadership programs, coaching of experiment group has significantly increased, but control group was significantly reduced. 3. Due to the situation leadership programs, empowerment of experiment group has significantly increased, but control group was significantly reduced. Therefore, the situation leadership programs can be effective in critical thinking, coaching, empowerment of nurse leaders. And applying the situation leadership program to the nurse in future, it would be helpful promoting empowerment, coaching, critical thinking in organization life and cope with situation that occurred during clinical.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.3
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• pp.3833-3839
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• 1975

The object of this experiment is to find out some flow characteristics of water through sand layer, to prevent moving sands in the filters of the fill Dam, infiltration gallery, well and Deversion Weir. This experiment was accomplished with different particle Sizes of Six Samples and different hydraulic gradient. The results obtained are Summarized as follows. 1. The critical hydraulic gradients for laminar flow was found to be between 1 and 2 when the sand used had the effective diameter, D10 of between 0.18cm and 0.45cm. 2. The critical hydraulic gradients for different particle sizes of sands were varied considerably. 3. There was a negative correlation between critical hydraulic gradient and critical Velocity, and between effective particle diameter D10 and critical hydraulic gradient respectively. 4. In spite of relatively small variation of void ratio of sands used, the values of the coefficient of permeability varied considerably. There was a negative correlation between coefficient of permeability and void ratio.

• Journal of the Korean Applied Science and Technology
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• v.20 no.1
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• pp.51-56
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• 2003

Garlic extract using super-critical carbon dioxide is influenced by temperature and pressure, and the optimum condition can make under super-critical state. We can know the defects in process of super-critical extration, It can indicate the drop of product rate, energy loss and equipment expense etcs. The minimum inhibition concentration of microbe which garlic extract contains has apperared the concentration more than 800ppm in this experiment. According to the result of this experiment, we can know that the antibiosis effect in the microbe of staphylococcus and fungus has disappeared in the incubation time more than 12 hours.

• Journal of the Korean Society for Railway
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• v.3 no.1
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• pp.12-18
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• 2000

This paper addresses the experimental study on the nonlinear critical speed and the validity of simple prediction formulation. The experiment on nonlinear critical speed is carried out using roller rigs, which has been impossible on track because of a possibility of an accident. In addition, experiment for a bogie is performed to check the difference in modeling a full railway vehicle and a bogie. It is found that nonlinear critical speed proves to be an inherent phenomenon of a railway vehicle itself and the difference of test results between a full railway vehicle and a bogie is comparatively negligible. Finally. the accuracy of simple prediction formulation for outbreak velocity and response frequency in hunting is investigated.

• Journal of the Korean Society of Safety
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• v.21 no.5 s.77
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• pp.1-5
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• 2006

This study provides a basic data necessary to design a facility of smoke management after calculating the critical velocity of the gradient scale model tunnel and reviewing its adequacy to establish an optimum disaster prevention system for a road tunnel at fire. The experiment is carried out by using Froude scaling to a scale model which is about 1/29 as big as the real tunnel, and its critical velocity calculation is calculated to the 0-2% gradient of the tunnel. The result shows that the higher the gradient is, the stronger the critical velocity, but that it doesn't affect the critical velocity so much when the gradient is less 2%. In addition, this result is studied in comparison with the results done by other researchers to review the adequacy of the critical velocity.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.191-196
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• 1997

As a part of International Criticality Safety Benchmark Evaluation Project (ICSBEP), SAXTON critical experiments were reevaluated. The effects on $K_{eff}$ of the uncertainties in experiment parameters, fuel rod characterization, soluble boron, critical water level, core structure, $^{241}$ Am and $^{241}$ Pu isotope number densities, random pitch error, duplicated experiment, axial fuel position, model simplification, etc., were evaluated and added in benchmark-model $k_{eff}$. In addition to detailed model, the simplified model for Saxton critical experiments was constructed by omitting the top, middle, and bottom grids and ignoring the fuel above water.r.r.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.130-135
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• 2010

In this paper, the shading ratio about to output the minimum critical power of a photovoltaic panel was determined by experiment and simulation. A 2.475[kW] poly-crystalline photovoltaic panel consisting of 11 modules was used in the experiment and its surface was covered with shading curtains, thus the amount of light incident to the modules were controlled. In order to compare with the experimental results, the experimental circuits were modelled with the CASPOC (power electronics electrical drives simulator) and module parameters were applied to it, by which the minimum critical power was calculated. As a result, the photovoltaic panel was about to generate the power when the 5th shading curtains were removed from the module surface, after then the output power linearly increased by removing the shading curtains. In addition, the CASPOC simulation results were similar to the experimental results in the abrupt decreasing pattern of power.

• Proceedings of the Korean Society of Crop Science Conference
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• 1991.05a
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• pp.76-77
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• 1991

• Wind and Structures
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• v.27 no.2
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• pp.71-88
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• 2018

At the University of Western Ontario (UWO), numerical tools represented in semi-closed form solution for the conductors and finite element modeling of the lattice tower were developed and utilized significantly to assess the behavior of transmission lines under downburst wind fields. Although these tools were validated against other finite element analyses, it is essential to validate the findings of those tools using experimental data. This paper reports the first aeroelastic test for a multi-span transmission line under simulated downburst. The test has been conducted at the three-dimensional wind testing facility, the WindEEE dome, located at the UWO. The experiment considers various downburst locations with respect to the transmission line system. Responses obtained from the experiment are analyzed in the current study to identify the critical downburst locations causing maximum internal forces in the structure (i.e., potential failure modes), which are compared with the failure modes obtained from the numerical tools. In addition, a quantitative comparison between the measured critical responses obtained from the experiment with critical responses obtained from the numerical tools is also conducted. The study shows a very good agreement between the critical configurations of the downburst obtained from the experiment compared to those predicted previously by different numerical studies. In addition, the structural responses obtained from the experiment and those obtained from the numerical tools are in a good agreement where a maximum difference of 16% is found for the mean responses and 25% for the peak responses.