• International Journal of Korean Welding Society
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• v.5 no.1
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• pp.44-52
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• 2005

The purpose of this study is to establish a design tool for the shrinkage margin of a deckhouse caused by welding and flame straightening. In order to do it, the effects of heat intensity and internal/external restraint condition on the shrinkage of the simple weldments were investigated, in order to identity the principal factors controlling shrinkage caused by welding process and flame straightening. Based on the results, predictive equations for longitudinal and transverse shrinkage at the welded structure were formulated as the function of heat intensity and in-plane rigidity. These equations were verified by comparing predicted results with the measured results at a panel structure of deckhouse.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.5
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• pp.42-53
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• 1988

The effects of ignition position on combustion in a chamber with swirl flow were investigated by use of hot wire anemometer, high speed schlieren photography, and chamber pressure measurement. In experiments, the closed-constant volume combustion chamber was used, and the swirl was formed unsteadily by suction of external fluid after reducing pressure in the chamber. Results show that the effect of ignition position on combustion depends on the flow state and the flame propagation distance corresponding to each ignition position. Also, the effect of combustion promoting increases as an ignition position moves from the center of chamber to the outside, but maximum burning pressure was obtained at the position that is the shortest flame propagation distance.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.383-391
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• 2020

Purpose: To identify internal self ignition and ignition caused by external flames in energy storage rooms, and to analyze the difference between ignition due to overheating and ignition caused by external heat sources. Method: membrane melting point measurement, battery external hydrothermal experiment, battery overcharge experiment, comparative analysis of electrode plate during combustion by overcharge and external heat, overcharge combustion characteristics, external hydrothermal fire combustion characteristics, 3.4 (electrode plate comparison) / 3.5 (overcharge) /3.6 (external sequence) analysis experiment. Result: Since the temperature difference was very different depending on the position of the sensor until the fire occurred, it is judged that two temperature sensors per module are not enough to prevent the fire through temperature control in advance. Conclusion: The short circuit acts as an ignition source and ignites the mixed gas, causing a gas explosion. The electrode breaks finely due to the explosion pressure, and the powder-like lithium oxide is sparked like a firecracker by the flame reaction.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.188-196
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• 2004

To optimize and limit the axial length of baffle in KSR-III engine, stability rating tests using pulse gun as one of artificial disturbance devices have been done. Decay time and other parameters for the evaluation of stabilization ability of engine to external perturbation have been analyzed to quantify stabilization capacity of engine, in other words, dynamic stability margin. If baffle does not cover flame zone enough which can be considered as collision region of injector, it wasn't be able to suppress external perturbation sufficiently. The limit of combustion stability margin of engine is assumed to be 50 mm length baffle.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.1
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• pp.130-135
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• 2005

The electrical fire frequently happens through careless use such as poor contact, mechanical stress on power cord sets. In this paper, we simulated a wall-model in order to investigate the patterns of fire dispersion on power cord sets which consists of vinyl cord and rubber cord, etc. The fire progress and dispersive patterns were measured by a high speed imaging system(HG-100K, REDLAKE, USA). From the results, the fire pattern of power cord sets was progressed in order of flashover, scattering and disconnection. The short-circuit of the vinyl cords happened easier than the rubber cords by the external flame. In case vinyl cord is disconnected. the fire progress is not observed because the ignition energy decreases. Whereas, the fire progressed continuously in case of the rubber cord.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1836-1843
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• 2017

In this paper, we investigated fire cases those are believed to be caused by explosion of a electrolytic motor start capacitor. Using two types of commercially available electrolytic motor start capacitors, capacitor current and the possibility of capacitor explosion were tested. And the ignition possibility of the internal material leaked from a capacitor was also tested. In addition, experiments were conducted to see if the fire could spread when a capacitor was exposed to an external flame. From our test we observed that the current of the electrolytic motor start capacitor rose continuously to a certain level by product, if the capacitor was continuously energized with working voltage, and then the capacitor was exploded. The gas and liquid leaked from the capacitor by the explosion could ignite by an electric arc and an external flame. The capacitor current at explosion was different product by product, but each product had a certain current level at explosion. And the increase rate of the capacitor current until explosion was 24% and 31% for the products used in the experiment. We proposed the capacitor explosion prevention method that cuts off power when the capacitor current rises to a certain threshold level. The proposed method can be used if the current of the applied electrolytic motor start capacitor rises continuously and then the capacitor is exploded at a certain current level when the capacitor is energized continuously.

• Asian-Australasian Journal of Animal Sciences
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• v.4 no.3
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• pp.263-274
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• 1991

Digestibilities of nutrients and energy are among the most important parameters to be determined in feed evaluation research. The apparent digestibility coefficients (ADC) of protein, total carbohydrate (TCHO), fat, energy and amino acids were determined for 14 common feed ingredients using chromic oxide as external indicator with Israeli carp (Cyprinus carpio). The ingredients tested were; corn, corn starch, gelatinized starch, wheat middling, wheat grade inferior, corn gluten meal, rapeseed meal (solvent extracted), soybean meal (solvent extracted), blood meal (drum dried), feather meal(hydrolyzed), file fish meal (flame dried), sardine fish meal (steam dried), sardine fish meal (flame dried) and brewers yeast (dehydrated). The overall ADC values were high in Israeli carp showing high capacity to digest their feed ingredients irrespective of plant or animal sources. In addition the ADC of plant protein was high enough to support the successful supplementation of fish meal with other plant proteins.

• Transactions of the Korean hydrogen and new energy society
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• v.2 no.1
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• pp.47-56
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• 1990

Pure titanium rods were oxidized by anodic oxidation, furnace oxidation and flame oxidation and used as a electrode in the photodecomposition of water. The maximum photoelectrochemical conversion efficiency(${\eta}$) was found for flame oxidized electrode ($1200^{\circ}C$ for 2 min in air), 0.8 %. Anodically oxidized electrodes have minimum photoelectrochemical conversion efficiencies, 0.3 %. Furnace oxidized electrode ($800^{\circ}C$ for 10min in air) has 0.5% phtoelectrochemical efficiency and shows a band-gap energy of about 2.9eV. The efficiency shows a parallelism with the presence of the metallic interstitial compound $TiO_{O+X}$(X < 0.33) at the metal-semiconductor interface, the thickness of the sub oxide layer and that of the external rutile scale.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.3
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• pp.78-86
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• 2016

In this paper we propose a new frame transfer function model describing the variations of a heat release rate in response to an external flow oscillation in gas turbine systems. A critical difference of our model compared to the so-called $n-{\tau}$ model which has been widely used for a prediction of combustion instability (CI), is that our model is able to describe a nonlinear relation between phase and frequency. In contrast, the phase part of the $n-{\tau}$ model is a pure time delay and thus the phase should be a linear function of frequency, which is inconsistent with many experimental results of real combustion systems. For an illustration, our new model is applied to experimental data and the effect of phase nonlinearity is investigated in the context of combustion instability.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.6
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• pp.442-448
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• 2009

To evaluate the combustion mechanism of each droplet cluster downstream of the premixed spray flame, the simultaneous time-series measurements were conducted by using optical measurement system consisting of laser tomography, multi-color integrated Cassegrain receiving optics (MICRO) and phase Doppler anemometer (PDA). Furthermore, the group combustion number of droplet cluster was estimated experimentally, and the combustion mechanism of droplet cluster was examined applying the theoretical analysis. The group combustion number, $G_c$, was experimentally estimated about all droplet cluster verified by planar images, and it was classified into the internal group combustion mode and the external group combustion mode according to the theoretical analysis. It is found that there are cases in which the group combustion number estimated experimentally for droplet cluster agree or disagree with the classification by theoretical analysis. The reason of disagreement is considered due to that the group combustion number was only estimated by the geometrical arrangement of droplets in cluster, and that the actual phenomenon is three-dimensional but the measurement system is two-dimensional.