• Journal of Technologic Dentistry
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• v.18 no.1
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• pp.67-72
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• 1996

This test is verifying for influence of W/P ratio of investment upon dental prosthesis Firstly we made 40 MOD die and divide 4 groups, each group take 0.2 different w/p ratio grade such as 0.35, 0.37, 0.39 and 0.41. The method of data analysis applied were by ANOVA, Tukey test and Mann-Whiney and Kruskal Wallis test. The finding of this study were as follows : 1. The 0.37 w/p ratio group showed most accurte margin due to $15.8{\mu}m$ gap between margin and die which keep up with manufacture's instruction and 0.35 w/p ratio group was followed as second accuracy group o 새 $48.3{\mu}m$ gap between margin and die, 0.39 w/p ratio group showed $101{\mu}m$ gap and 0.41 w/p ratio group showed $129.8{\mu}m$ gap. 2. As to the relationship of the margin accuracy between 4 different grade of w/p ratio groups, each group was statistically significant(P<0.01). Also the all groups were statistically significant except between 0.35 and 0.37 groups between 0.39 and 0.41 groups, and between 0.35 and 0.39 groups. 3. A consequence of Mann-Whitney & Kruskal-Wallis test for marginal accuracy between 4 different grade of w/p ratio was statistically significant as same as above ANOVA test result. Also Tukey test for verifying similarity from each group showed same as above.

• Fire Science and Engineering
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• v.13 no.2
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• pp.3-11
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• 1999

New examination of a predictive model for the ISO 9705 room-corner test have been m made for materials studied by L S Fire Laboratories, Italy. The ISO 9705 test subjects wall a and ceiling mounted materials to a comer ignition source of 100 kW for a duration of 10 m minutes; if flashover does not occur this is followed by 300 kW for another 10 minutes. The m materials that did not stay in place during combustion because of melting, dripping, or d distorting were simulated by an adjustment to the material's total available energy. For m mat려als that remain in place the simulation model appears to do well in its prl어ictions. A l large-s떠Ie room test results 뾰 compar벼 with the m여el’s prediction also.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.11
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• pp.951-956
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• 2008

The high temperature creep properties of the generating plant's high temperature tube, pipe and header and such are very significant in accordance with long-time exposure to the high temperature and pressure environment. Not only this, but as the welding procedure is compulsory for the cohesion of components, the creep properties regarding the local microstructures of steel weldment are very important. In order to understand the creep properties regarding the local microstructures of steel weldment, the SP-Creep test which is easy to get sample from the field component was conducted. The local microstructure of steel weldment, that is, W.M. and B.M.'s microstructures were observed using the SEM. The rupture time of W.M. was longer as 110 % averagely in a same condition, which is the consequence of the difference of the microstructure. Each lethargy coefficient of B.M. and W.M. is evaluated by the relation among the temperature, load and the rupture time from SP-Creep Test. The life estimation equation can be induced by the transformation of Power-law. B.M. and W.M. for each $550\;^{\circ}C$ and $575\;^{\circ}C$, the very similar to normal temperature of the domestic thermal power generation in working, are estimated.

• Journal of the Korean Institute of Gas
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• v.12 no.1
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• pp.25-30
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• 2008

A Numerical study was carried out for a propane gas pool fire in the fire test room of $2.5m{\times}2.0m{\times}2.5m$ for testing a inert gas water mist system, to investigate a possible under-ventilation in the fire test room. For the fire sizes of 60 kW and 120 kW, changes in the temperature and CO concentration with and without a window were investigated. It was confirmed that the influence of the window on the distributions of temperature and CO concentration was small in the two fire sizes, and hence the under-ventilation was not occurred in the room.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.555-562
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• 2008

In this paper we proposed a practical low-power design technique using clock-gating in RTL. An efficient low-power methodology is that a high-level designer analyzes a generic system and designs a controller for clock-gating. Also the desirable flow is to derive clock-gating in normal synthesis process by synthesis tool than to insert directly gate to clock line. If low-power is considered in coding process, clock is gated in coding process. If not considered, after analyzing entire operation. clock is Bated in periods of holding data. After analyzing operation for clock-gating, a controller was designed for it, and then a low-power circuit was generated by synthesis tool. From result, we identified that the consumed power of register decreased from 922mW to 543mW, that is the decrease rate is 42%. In case of synthesizing the test circuit using synthesizer of Power Theater, it decreased from 322mW to 208mW (36.5% decrease).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1265-1266
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• 2013

• Journal of Mechanical Science and Technology
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• v.17 no.6
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• pp.879-887
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• 2003

The flow in a parallel walled test channel, when obstructed with a geometry at the entrance, can be forward, reverse and stagnant depending on the position of the obstruction. This interesting flow phenomenon has potential benefit in the control of energy and various flows in the process industry In this experiment, the flat plate obstruction geometry was used as an obstruction at the entry of the test channel. The parameters that influence the flow inside and around the test channel were the gap (g) between the test channel and the obstruction geometry, the length (L) of the test channel and the Reynolds number (Re). The effect of the gap to channel width ratio (g/w) on the magnitude of the velocity ratio (V$\_$i/ / V$\_$o/ : velocity inside/ velocity outside the test channel) was investigated for a range of Reynolds numbers. The maximum reverse flow observed was nearly 20% to 60% of the outside velocity for Reynolds number ranging from 1000 to 9000 at g/w ratio of 1.5. The maximum forward velocity inside the test channel was found 80% of the outside velocity at higher g/w ratio of 8. The effect of the test channel length on the velocity ratio was investigated for different g/w ratios and a fixed Reynolds number of 4000. The influence of the Reynolds number on the velocity ratio is also discussed and presented for different gap to width ratio (g/w). The flow visualisation photographs showing fluid motion inside and around the test channel are also presented and discussed.

• Proceedings of the PSK Conference
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• 2000.04a
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• pp.192.1-192.1
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• 2000

• Fire Science and Engineering
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• v.26 no.2
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• pp.105-111
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• 2012

In this research, aluminum composite panels of the general materials and fire retardant materials as building claddings make researches about fire performance comparison analysis. Test methods of the small and medium cone calorimeter experiments and SBI (Single Burning Item) experiments was applied to the determination. As a result, in the experiments peak heat release rate cone calorimeter the general aluminum composite panel $1,293kW/m^2$ ($75kW/m^2$), flame-retardant aluminum composite panel $70kW/m^2$ ($75kW/m^2$) was measured. In the SBI experiments fire growth rate the general fire aluminum composite panel is approximately 743 W/s and the flame-retardant aluminum composite panel is approximately 97 W/s of the value were measured. Thus, a standards enactment are urgently required in this case it is used as building claddings of the aluminum composite panel by fire risk assessment.

• Fire Science and Engineering
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• v.26 no.5
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• pp.21-27
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• 2012

A real A real scale fire test was performed in accordance with KS F ISO 9705 test method to investigate the combustion characteristics of glass wool sandwich panels. To do this, six kinds of specimens having different density and thickness were examined. The glass sandwich panels were installed inside the room, which had internal dimensions of 2.4 m wide${\times}3.6m$ deep${\times}2.4m$ high. also, combustion characteristic are determined through the exposure of specimens to flame by the propane gas burner has a capacity of 100 kW (10 minutes) and 300 kW (10 minutes) for total 25 minutes of test time. Results of the real sale fire test, it was found that maximum HRR of each specimen was 333.2~365.5 kW, maximum heat flux was 12.4~12.9 kW/$m^2$ And, maximum internal temperature for all specimens was not over $500^{\circ}C$. During the real scale fire test, flash-over didn't occur and the difference by density and thickness of specimen was not found from the results of HRR, heat flux, and internal temperature measurement.