• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.176-179
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• 2011

국내에서는 방화구획을 설정하여 화재 확산 방지 및 재실자의 대피 시간을 확보하고 있다. 방화구획에 설치되는 방화문은 방화문의 내화시험방법(KS F 2268-1)에 따라 시험을 거쳐 성적서를 발급 받은 제품에 대해 설치하도록 의무화 하고 있다. 그러나 본 시험방법은 시험체 제작, 설치 및 의뢰시험비용 등 상당한 비용이 소요될 뿐 아니라 제작, 설치, 시험에 소요되는 시간 또한 길다. 축소실험장치는 목재방화문 개발 중 재료의 내화성능을 평가할 장치로 개발되었으며, 표준시간-가열 온도곡선을 상회하는 가열실험을 통해 재료의 내화성능 결과를 얻을 수 있다. 본 실험에서는 난연 또는 불연성능이 뛰어난 재료를 대상으로 실험하였으며, 그 결과 난연목재는 5분, 마그네슘보드와 내화 직물원단은 60분의 내화성능을 갖춘 것으로 확인되었다. 이 결과를 토대로 방화문의 내화시험방법과 상관성을 도출하여 목재방화문 개발의 지표로 활용 가능하게 되었다.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.110-116
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• 1997

Growth curves of seven strains of lactic acid bacteria isolated from Kimchi were graphed during cultivation at 1$0^{\circ}C$, 2$0^{\circ}C$, 3$0^{\circ}C$ and 4$0^{\circ}C$ in filter sterilized Chinese cabbage juice, and then lag time and generation time at each conditions were calcurated. At 3$0^{\circ}C$, the lag time of Leu. mesenteroides subsp. dextranicum was 168 min(minutes), Leu. mesenteroides subsp. mesenteroides 204 min, Leu. paramesenteroides 612 min, Lac. bavaricus 258 min, Lac. homohiochii 228 min, Lac. plantarum 270 min and Lac. brevis 264 min. And at this temperature, the generation times of Leu. mesenteroides subsp. dextranicum and Leu. mesenteroides subsp. mesenteroides were all 36 min, Lac. bavaricus 33 min, Lac. homohiochii 39 min, Lac. plantarum 66 min, Lac. brevis 42 min and Leu. paramesenteroides 162 min. As cultural temperature was lowed from 3$0^{\circ}C$ to 1$0^{\circ}C$, all strains showed remarkable prolongations in lag time and in generation time, and the prolongations were most conspicuous in Lac. plantarum. At 1$0^{\circ}C$, 2$0^{\circ}C$ and 3$0^{\circ}C$, both the lag time and the generation time of Leu. mesenteroides subsp. mesenteroides were shorter than those of Lac. plantarum. But at 4$0^{\circ}C$, this pattern was completely inverted. As a whole lower temperatures were more favorable for the growth of Leu. mesenteroides subsp. mesenteroides, while higher temperatures were for Lac. plantarum.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.1
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• pp.8-13
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• 1990

The microscopic relaxation parameters for the single crystal were measured by using thermally stimulated depolarization (TSD). Initial rise method, various heating rate method and total glow peak method were used for the determination of the activation energy and Debye relaxation time from TSD glow curves. Activation energy, pre-exponential factor and relaxation time for impurity-vacancy dipole reorientation were 0.55eV, 1.97$\times$10 super(-12) sec and 12.19sec in average, respectively. Dielectric dissipation factor for the crystal was calculated from the measured TSD glow curve, its value being about 3$\times$10 super(-2).

• Korean Journal of Food Science and Technology
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• v.22 no.5
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• pp.575-581
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• 1990

The existence of the equivalent point for a thermal processing system was demonstrated using arbitrarily chosen ideal direct heating curves. i.e. isothermal heating curves at $120^{\circ}C$ for 10min and at $135^{\circ}C$ for 10sec. Under these conditions, G-values and F-values were calculated at various values of Ea- and z-values by applying the Arrhenius and the Bigelow models respectively. The equivalent time and equivalent temperature were determined by both line intersection and linear regression methods. The equivalent points estimated by both the line intersection and the linear regression methods were consistent and their values were the same as the heating time and temperature of the ideal direct heating curves.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.1
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• pp.11-15
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• 1988

Square slices of sea tangle was dried in constant condition of thickness (1.54mm), air temperature $(50^{\circ}C)$, relative humidity $(30\%)$ and air velocity (0.4m/s). The shrunk surface area and the shrinking rate were investigated. The results obtained are summarized as follows : 1) Comparing the shrinking of transverse section with that of vertical section, the transverse section was proceeded more double shrinkage than vertical section. 2) The shrunk surface area curve showed nearly a linear shrinkage up to 90min of drying time. 3) The shrinking rate was rapidly increased in first falling rate period, and was largest in the early period of second falling rate period.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1807-1813
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• 2007

The study aims at analyzing an underground station refuge model using EXODUS, one of the refuge simulation programs. The model for simulation is the Daegu Subway (Joongang-ro station). The details of the accident are referred to as the simulation condition the refuge time of traveling from the $3^{rd}$ basement platform to the $1^{st}$ basement is mainly calculated, with passengers numbering 1,000 including 329 at car 1079, 320 at car 1080, and 360 who are not on board. Reference data is used to set up the position of passengers. CFAST fire simulator is also used, and a fast curve among the $t^2$ growth curves, selected as fire growth scenario. The zone is divided into a total of 24 including 18 at the $3^{rd}$ basement platform and 6 at the $2^{nd}$ basement the $1^{st}$ basement is excluded in the fire simulation, however.

• Journal of the Korea Institute of Building Construction
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• v.16 no.5
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• pp.389-395
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• 2016

The evolution of electro-mechanical impedance (EMI) of the piezoelectricity (PZT) sensor was investigated to determine the setting times of cementitious materials in this study. The PZT sensor coated with non-conductive acrylic resin was embedded in cement paste before casting and the EMI signatures were continuously measured. Vicat needle test and semi-adiabatic calorimetry test were also conducted to justify the validity of EMI senssing technique in setting monitoring of cementitious materials. The results show that significant changes in EMI resonant peak magnitude and frequency during setting process were observed, and that the setting times determined by EMI sensing technique were relevant to the setting times measured by Vicat needle test and semi-adiabatic calorimetry test.

• Journal of the Korean Ceramic Society
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• v.35 no.6
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• pp.640-646
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• 1998

Nucleation and crystallzation of a quaternary glass system for lead titanate glass-ceramics were in-vestigated using DTA(differential thermal analysis ) with variation of nucleation temperature and crystal growth time. Glass samples containing 60mol% of PbO-{{{{ { TiO}_{2 } }} were prepared from melts by the conventional normal cooling method in a cylindrical brass mould. The glass sample was nucleated between 40$0^{\circ}C$ and 50$0^{\circ}C$ for a given time and showed the maximum nucleation rate at 46$0^{\circ}C$ The DTA crystallization peak temperature decreased with increasing nucleating time and decreasing heating rate during DTA runs which indicated an increase of the number of nuclei produced in the system.

• KSBB Journal
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• v.16 no.4
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• pp.430-434
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• 2001

Microorganisms of livestock wastewater were microscopically examined to identify bacillus types with optimal absorbance at 630 nm. Growth cuties of microorganisms at various levels of livestock wastewater (5, 10, 20, 30, 40, 50%) and different temperatures (20$\^{C}$ , 37$\^{C}$) were prepared to determine dilution at which microorganisms did not grow within 1 hour of inoculation, regardless of levels and temperatures. Heat treatment of livestock wastewater at 10 0$\^{C}$ for 2 minutes was good enough to inhibit the growth of microorganisms at 20$\^{C}$ and 37$\^{C}$. A good linear relationship was obtained between levels of livestock wastewater and absorbance at 630 nm (R=98.88%) and dry cell weight (98.98%). The dry cell weight of microorganisms in livestock wastewater was 0.375 g/L.

• Elastomers and Composites
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• v.49 no.2
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• pp.144-148
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• 2014

Compression set (CS) and weight loss by thermal degradation of the ACM rubber composite sample prepared for an automotive part were measured simultaneously at several given temperatures of $150^{\circ}C$, $160^{\circ}C$, $170^{\circ}C$, and $180^{\circ}C$. Using the relationship between them, thermal life of the sample could be predicted at a given operating temperature by applying Toops method which is based on the analysis of non-isothermal TGA thermograms. Conversion by weight loss showed a linear relationship with CS changes, exhibiting 4.2% at CS 40%. Activation energy of thermal degradation was calculated as 120.2 kJ/mol at 4.2% of weight loss from Flynn-Wall-Ozawa analysis. When the expected life was set as time to reach CS 40% at $120^{\circ}C$, the life time of the sample was calculated as 9,700 hrs when Toops method was applied.