• Journal of Korean Society of Steel Construction
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• v.27 no.2
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• pp.143-153
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• 2015

In this paper, the standard fire resistance test under load and associated numerical study were carried out to evaluate the fire resistance of unprotected partially encased beams and slimfloor beams. The temperature evolution and the deflection increase of the composite beam specimens were investigated and the effects of the key behavioral parameters including the load ratio, the reinforcement, and the fire exposure were analyzed. The test results showed that the temperature rise of the partially encased beams and slimfloor beams is considerably slow compared to the conventional H-shape composite beams. Up to at least 90 minutes, the reinforcements in the partially encased composite beams maintained below the temperature at which the cold steel strength is sustained. Unprotected partially encased beams and slimfloor beams in the experimental program achieved the fire resistance more than 2 hours according to the limiting deflection criteria. This implies that unprotected partially encased beams and slimfloor beams can be very promising alternatives to enhancing the fire resistance of steel beams. This study also conducted the fully coupled thermal-stress analysis by using the commercial code ABAQUS to the thermal and structural behaviour of composite beams in fire. The numerical predictions provide acceptable correlations with the experimental results.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.601-606
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• 2021

This study investigated the quality and sensory properties of Tteokgalbi containing various amounts of roasted garlic powder by measuring the proximate composition, color, pH, cooking yield, electronic tongue, and sensory evaluation. Samples containing 3% and 5% roasted garlic powder had lower moisture content than the control group (p<0.05), however, protein content was higher (p<0.05). The redness of samples containing 3% and 5% roasted garlic powder was significantly higher compared to the control (p<0.05). pH decreased significantly with increasing amounts of roasted garlic powder (p<0.05). Cooking yield exhibited an upward trend with increasing levels of roasted garlic powder. The intensity scales of saltiness, sourness, and umami of samples containing roasted garlic powder were stronger than those of the control. Samples containing 3% roasted garlic powder scored the highest flavor and overall acceptability. These results indicate that adding 3% roasted garlic powder can enhance the quality and sensory properties of pork Tteokgalbi.

• Korean Journal of Optics and Photonics
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• v.1 no.2
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• pp.135-141
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• 1990

Optical nonlinearity of laser heated Si with thickness of 160$\mu$m is investigated by pump-probe method. Si is heated by pdsed Nd:YAG laser of $TEM_{00}$-mode with pulse duration of 180$\mu$sec. Temperature change is monitored by observing transmittance change of probe light whose wavelength lies near band gap of Si. It is found that temperature rise is linearly proportional to incident laser intensity and the maximum temperat~re increment is measured to be $16^{\circ}C$ for the maximum incident intensity of 25KW/$\textrm{cm}^2$. From these results, the third order nonlinear susceptibility .d3) at the wavelength of 1.06$\mu$mis estimated to be $6.6\times10^{-5}$esu due to laser heating.

• Korean Journal of Food Science and Technology
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• v.48 no.3
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• pp.262-267
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• 2016

Physicochemical characteristics of chicken-thigh emulsion manufactured with different concentrations of NaCl (0, 0.3, 0.6, 0.9, 1.2, and 1.5%) were examined. Moisture and ash contents of samples containing 1.2% and 1.5% NaCl were significantly higher than those of the other samples (p<0.05). Protein contents decreased with increasing NaCl concentration. The pH values of batters significantly decreased with increasing NaCl concentration (p<0.05). The lightness values of uncooked and cooked samples showed an upward trend with increasing concentration of NaCl. Redness and yellowness values of uncooked batters containing 1.2% and 1.5% NaCl were significantly lower than other samples (p<0.05). The cooking yield and viscosity of the samples increased with increasing NaCl concentration. Samples containing 1.2% and 1.5% NaCl showed higher viscosities than the controls and samples containing 0.3-0.9% NaCl. Therefore, it can be concluded that addition 1.2% NaCl in chicken thigh products is beneficial.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.3
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• pp.268-274
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• 1984

The purpose of this study was to investigate the physico-chemical effects of a potato starch and a purified potato starch under the condition of the microwave heating. They were exposed to the microwave energy in a 950 W, 2,450 MHz oven for 30 through 120 seconds. As the microwave heating time was increased, the contents of moisture and the crude fat of the samples were remarkably decreased irrespective of the starch composition, but on the other hand the contents of crude ash was slightly decreased and the crude protein was almost unchanged. The rings of crystallinity come to gradually changed in the X-ray diffraction pattern, and then the only 1 ring, of which interplanner spacing is wide, is changed strikingly. As the microwave heating time is increased, the starch granules which observed by a scanning electron microscope were broken partially with a special form, and the granules of purified potato starch were broken faster than those of potato starch. With the same condition that the microwave heating time was increased, while the gelatinization temperature comes to fall, the swelling power and the solubility were increased. Besides these, while the gelatinization temperature of the purified potato starch was lower than that of the potato starch, both the swelling power and the solubility of the purified potato starch is higher than those of the potato starch.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.4
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• pp.112-120
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• 2001

Poor fuel vaporization in gasoline engines causes the problem of HC emission during the cold start and warm-up period. This paper presents a strategy to improve fuel atomization during the warm-up phase. In this experiment, the heated fuel-rail system is constructed to investigate the effects of fuel heating on the average size of fuel droplets. The fuel atomization effects are examined by measuring Sauter Mean Diameter (SMD) of the fuel droplets from the three different types (two-hole, pintle, and six-hole) of injectors based upon a returnless heated fuel-rail system. The results show that the six-hole type injector is the most sensitive to fuel heating in terms of SMD among three different types of injectors.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.6
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• pp.90-95
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• 1997

In designing a resonant circuit of the inverter which puts induction heating with high frequency to the load, an inductance L of the circuit, the coupling coefficient of a transformer transfering the output power to load, and the coupling coefficient of load circuit heating with coil affect to the output power of a resonant circuit, the circuit Q and the frequency. Those characteristics of the circuit are analyzed through Thevenan's equivalent circuit of the coupling coefficient type which is derived from the T-type equivalent circuit of a transformer. On this equivalent circuit, the impedance of a transformer referred to its primary side is not only proportional the square of turn ratio, nZ, but also the square of coupling coefficient, K2 This paper proposed a more accurate fundamental method to design a resonant circuit of the inverter by using the Thevenan's equivalent circuit.

• Journal of Korean Society of Steel Construction
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• v.18 no.6
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• pp.717-726
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• 2006

Traditional external post-tensioning method using either steel bars or tendons is commonly used as a retrofitting method for steel composite bridges. However, the method has some disadvantages such as stress concentration at anchorages and inefficient load-carrying capability of live loads. Multi-stepwise prestressing method using thermal expanded coverplate is a newly proposed prestressing method, which was originally developed for prestressing steel structures. A new retrofitting method for steel girder bridges founded on a simple concept of thermal expansion and contraction of cover plate, the method is a hybrid of and combines the advantages of external post-tensioning and thermal prestressing. In this paper, basic concepts of the method are presented and an illustrative experiment is introduced. From actual experimental data, the thermal prestressing effect was substantiated and the FEM approach for its analysis was verified. The retrofitting effects ofa single-span bridge were analyzed and the feasibility of the developed method was examined.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.2
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• pp.209-214
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• 2016

The aim of this study was to investigate the effects of pork skin gelatin on the physicochemical properties (pH, CIE color value, water holding capacity, cooking yield, viscosity, proximate composition, and texture profile analysis) of emulsion-type sausage. Emulsion-type sausages were manufactured with 0% (control), 1%, 3%, and 5% pork skin gelatin. Moisture contents of samples containing 3% and 5% pork skin gelatin were significantly higher than those of the control and samples containing 1% pork skin gelatin (P<0.05). Protein contents were the highest in samples containing 5% pork skin gelatin (P<0.05). The pH values of uncooked and cooked samples increased with increasing pork skin gelatin level (P<0.05). The lightness and yellowness values of cooked samples containing pork skin gelatin were higher than those of the control (P<0.05). In addition, redness values of cooked samples containing 3% and 5% pork skin gelatin were significantly lower than those of the control and samples containing 1% pork skin gelatin (P<0.05). Water holding capacity (WHC) was the lowest in control, and samples containing 3% and 5% pork skin gelatin had significantly higher WHC compared to the other samples (P<0.05). Cooking yield of samples increased with increasing concentration of pork skin gelatin (P<0.05). Samples containing 3% and 5% pork skin gelatin showed higher viscosity than the control and sample containing 1% pork skin gelatin (P<0.05). Springiness, cohesiveness, and chewiness of samples were not significantly different among the samples. Hardness values of the control and sample containing 1% pork skin gelatin were lower than those of other samples (P<0.05), and samples containing 5% pork skin gelatin had the highest hardness (P<0.05). Gumminess of sample containing 5% pork skin gelatin was significantly higher than that of the control (P<0.05). The results show that pork skin gelatin could improve the potential of emulsion-type sausage physicochemical properties.

• Journal of the Korean Society of Radiology
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• v.9 no.4
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• pp.219-225
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• 2015

This study aims to evaluates the image quality of CR and DR that are scanned with the use of the attachable carbon heater X-ray scanner table equipped with heating device by measuring SNR and CNR before and after the attachment of the said table. In the aluminum staircase testing, CR increased SNR and CNR when attached with the table, while DR decreased SNR and CNR. In the human-body model phantom testing, CR increased SNR and CNR only in the low-energy low-dose radiation and the high-energy high-dose radiation, but decreased SNR and CNR under all other conditions. In conclusion, the use of such table can make the patient feel comfortable by removing his or her anxiety, thus helping the testing, but in the actual clinical application thereof, if the thickness and material of the bottom film and the protective film, including the carbon heater, are not considered, it affects the picture quality, thereby requiring continuous research on the use of such table.