• Fire Science and Engineering
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• v.24 no.2
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• pp.38-43
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• 2010

The purpose of this study is to secure the basis for judgment on the cause of an accident by analyzing the melting characteristics of a blade type fuse used for vehicles due to overload. In order to increase the reliability of the test, it was conducted by connecting the electrical system with conditions similar to those of an actual vehicle to apply the load. Carbonization pattern experiment of fuse by outside flame applied Korean Standard (KS). The fuse melted by the overcurrent showed a smooth cross-section while the test terminals, clear plastic body, etc., burnt out by the external flame was badly deformed. When 185% of the rated current (27.8A) was applied to a cable of 15A rated current onto which an over-capacity fuse (20A) was installed, the fuse melting time was 217 seconds. In addition, when a load current of 28.8[A] (139%) was applied, the fuse's test terminal and terminal blade were not burnt out although foam was observed on some parts of the plastic body. When a load capacity of 28.2[A] (141%) was applied to a cable of 15A rated current onto which an over-capacity fuse (30A) was installed, the fuse melting time was approximately 10 seconds. When a load current of 35.8[A] (119%) was applied, the fuse's test terminal and terminal blade were not burnt out, although some parts of the plastic body was swelled. However, it was observed that the switch terminal melted if approximately six minutes lapsed under such conditions. When a load capacity of 39.4[A] (131%) was applied to a cable of 15A rated current onto which an over-capacity fuse (30A) was installed, the fuse melted in approximately 69 seconds, and the test terminal and terminal blade were not burnt.

• Journal of the Korean Geotechnical Society
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• v.33 no.10
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• pp.59-69
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• 2017

The tension load of the ground anchor inserted in the ground gradually changes over time. In this regard the change of the initial tension load is primarily decreased by the fixation condition of the fixing head and the mechanical characteristics of the tensile material. The subsequent additional tension load is a time-dependent loss mostly due to the fixing conditions of the bonded length and the surrounding ground properties of the field. In this paper, therefore, a measurement system using a relative displacement detector that can relatively easily measure the change of tension load is discussed. As a result of the review, it was confirmed that the results using the relative displacement detector are similar to those of the real scale model test, and it was also confirmed that similar results were obtained with the result of the pull-out test conducted on the ground anchors fixed to weathered rocks condition. In addition, a pull-out test was conducted on the test anchors whose initial tension load loss was relatively large and through this test pull-out behavior of the tension type ground anchors was verified.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.4
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• pp.346-354
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• 1992

In the power-system, the active and reactive power levels of load bus randomly vary over days, months, and years which are stochastic in nature. This paper presents an algorithm for optimal Var planning considering the uncertainties of loads. The optimization problem is solved by a stochastic linear programming technique which can handle stochastic constraints to evaluate optimal Var requirement at load bus to maintain the voltage profile which results in probabilistic density function by stochastic Load Flow analysis within admissible range. The effectiveness of the proposed algorithm has been verified by the test on the IEEE-30 bus system.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1212-1218
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• 2003

A novel loading mechanism of wedge roller type has been developed. This type traction drive has long system life and high efficiency by changing the pre-load on a contact point. And this loading mechanism does not need precision machining. So it has, as opposed to the conventional loading mechanism, an advantage in saving manufacturing cost. In this paper, by analyzing pre-load generating mechanism, spring pre-load and the roller size are defined and the stress on the contact point by pre-load is calculated. On the basis of this analysis, the model of wedge roller type traction drive for the test is made and was carried out its performance test. It can transmit input torque up to 1.5 N m, with high efficiency over 91% up to 98%, with slip rate under 2.5%.

• Journal of the Korean Society of Safety
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• v.10 no.4
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• pp.3-8
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• 1995

Anchors find their use in providing tie-back resistance for submerged footings, transmission towers, tunnels and ocean structures. Laboratory model teats were performed for the short-term net ultimate uplift capacity of a circular anchors with respect to various embedment depths and moisture content in saturated bentonite. The tests have been conducted with the anchor at two different moisture contents. Based an the model test results, empirical relationships between the net load, rate of strain, and time have been developed. Test results are as follows. 1) In creep tests for load versus ultimate uplift capacity, the displacement of plate anchors rapidly increases during the primary stage but thereafter becomes constant over a period of time. 2) Displacement increased with the increase of the sustain load and embedded ratio in soil. 3) If the load is less than or equal to 75% of the short-term ultimate uplift capacity, a complete pullout does not occur due to creep.

• Geomechanics and Engineering
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• v.6 no.2
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• pp.195-211
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• 2014

Stone columns (or granular column) have been used to increase the load carrying capacity and accelerating consolidation of soft soil. Recently, the geosynthetic reinforced stone column technique has been developed to improve the load carrying capacity of the stone column. In addition, reinforcement prevents the lateral squeezing of stone in to surrounding soft soil, helps in easy formation of stone column, preserve frictional properties of aggregate and drainage function of the stone column. This paper investigates the improvement of load carrying capacity of isolated ordinary and geotextile reinforced sand column through field load tests. Tests were performed with different reinforcement stiffness, diameter of sand column and reinforcement length. The results of field load test indicated an improved load carrying capacity of geotextile reinforced sand column over ordinary sand column. The increase in load carrying capacity depends upon the sand column diameter, stiffness of reinforcement and reinforcement length. Also, the partial reinforcement length about two to four time's sand column diameter from the top of the column was found to significant effect on the performance of sand column.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1100-1105
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• 2008

In most drilled shafts construction sites, it is common, depending on the site condition, to use either water or slurry as fluids for maintaining stability of the holes, however, there are yet no design manuals by hole stability fluids. In this paper, in order to evaluate load transfer characteristics of the drilled shafts by hole stability fluids, two test piles are constructed over the soft ground of the lower Busan Bay based on the Bi-directional Pile Load Test. The test results showed that no ultimate states has found under the condition of applied loads with fresh water and slurry as hole fluids for drilled shafts. Then, the load transfer behavior were estimated with the data measured in fields and the effect of hole stability fluids were compared. All these results are presented in the paper.

• Journal of the Korean Geotechnical Society
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• v.20 no.8
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• pp.113-121
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• 2004

The present study is suggested to estimate the degree of secondary consolidation caused by various changes of stress such as loading, unloading and reloading in improving poor subsoil through pre-compression loading construction method and, for this purpose, examined the characteristics of the consolidation of Kunsan clay through incremental loading test (IL) using standard consolidation tester and constant loading rate test (CLR), which were adapted from the constant rate of strain test (CRS). In addition, after CRS test, this study determined the characteristics of secondary consolidation and relationships among void ratio, effective stress and time according to the ratio of effective over-consolidation on reloading at the point of time of random expansion. Kunsan clay had larger expansion and smaller secondary consolidation settlement when the ratio of effective over-consolidation was high. In addition, when loading was applied after the load was removed at once, the secondary consolidation coefficient $C'_{\alpha}$ was smaller than that when the load was removed gradually, and when the ratio of effective over-consolidation was over 1.4 a similar value was produced. Based on the entire settlement resulting from reloading, the secondary consolidation coefficient $C"_{\alpha}$ increased non-linearly with the lapse of time but the final value was similar to that in the case of rapid removal. The strain velocity of void ratio was in a regular linear relationship with the increase of loading time regardless of the ratio of effective over-consolidation in both tests and it grew smaller with the increase of the ratio of effective over-consolidation.tion.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.9
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• pp.1186-1191
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• 2014

Weekly and monthly electric load forecasting are essential for the generator maintenance plan and the systematic operation of the electric power reserve. This paper proposes the weekly maximum electric load forecasting model for 104 weeks with the multiple regression model. Input variables of the multiple regression model are temperatures and GDP that are highly correlated with electric loads. The weekly variable is added as input variable to improve the accuracy of electric load forecasting. Test results show that the proposed algorithm improves the accuracy of electric load forecasting over the seasonal autoregressive integrated moving average model. We expect that the proposed algorithm can contribute to the systematic operation of the power system by improving the accuracy of the electric load forecasting.

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.4
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• pp.508-525
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• 1992

The purpose of this study was to evaluate the effect of some resistance form designs on the bond strength of resin-retained prosthesis. Six sub-groups are designed in natural teeth group and resin teeth group . The framework designs in natural teeth group: 1) no groove preparation 2) groove at the center of distal surface 3) groove at the distobuccal line angle 4) 45 degree lateral load with no groove 5) 45 degree lateral load with center groove 6) splint two teeth with no groove. The framework designs in resin teeth group: 1) no groove preparation 2) groove at the center of distal surface 3) groove at the distobuccal line angle 4) metal covered the 1/2 of distal surface 5) metal covered the 1/2 of mesial surface 6) metal extended over the 114 of buccal surface. Specimens were treated electrolytic etching by Oxy-Etch and cemented with Panavia EX. Failure load was measured by Instron. Another 30 specimens were carried out fatigue tests by MTS 810 fatigue testing machine for 5000 cycles at different load level. The following results were obtained from this study. 1. The failure load was significantly increased by resistance forms. 2. The failure load was not increased by increase of total surface area bonded with teeth. The distal surface area played an important role in failure load. 3. In 45 degree lateral load group, the failure load was decreased significantly than that of in vertical load group. 4. Bond failure modes between static test and fatigue test exhibited no differences.