• Journal of the Korean Institute of Gas
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• v.21 no.4
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• pp.1-5
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• 2017

Leaking of natural gas, which is mostly methane, in a confined living space creates flammable atmosphere and gives rise to explosion accident. The minimum amount of leaked methane for explosion is highly dependent on the degree of mixing in the confined space. This paper proposes a method for estimating minimum amount of flammable gas for explosion by using Gaussian distribution explosion model(GDEM) and experimental explosion data. The explosion pressure in the confined space can be estimated by assuming the Gaussian distribution of flammable gas along the height of an enclosure and estimating the maximum amount of gas within flammable limits, combustion of the estimated gas with constant volume and adiabatic or isothermal mixing in the confined space. The predicted minimum gas amount for an explosion is tied to explosion pressure that results in a given building damage level. The result shows that very small amount of methane leaking in the confined space may results in a serious gas explosion accident. This result could be applied not only to setting the leak criteria for developing a gas safety appliance but also to accident investigating of explosion.

• Culinary science and hospitality research
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• v.23 no.6
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• pp.20-26
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• 2017

To guarantee the safety of rice cake production, the Hazard Analysis Critical Control Points system was applied to the production process. The purpose of this study was to analyze the microbiological hazards of the manufacture of rice cakes, and establish critical limits in the process of the manufacturing rice cakes. To control the microbiological hazards, the sterilization process was set to a critical limit. The process of manufacturing rice cakes can reduce these microbiological hazards during the steaming process. A microorganism test for each specimen was conducted three times and compared with before and after steaming processes. The finished product was conducted by microbiology experiment and the validity of the steaming process was verified. The results were determined to be capable of reducing the biological element of Critical Control Point via the steaming process. Microbiology such as aerobic plate count, coliform, Escherichia coli(E. coli), Listeria monocytogenes, Enterohemorrhagic E. coli, Salmonella spp., Bacillus cereus, Staphylococcus aureus and Clostridium perfringens was evaluated by the experimental method of Korean Food Standards Codex. Aerobic plate count was reduced by steaming process, and no microorganism were detected. All rice cakes in the finished product were judged to be safe for both the Escherichia coli and general bacteria. In conclusion, it suggested that a HACCP plan was necessary for management standard and systematic approach in the establishment of critical limit, problem resolution, verification method, education, and records management. Based on this study, it is intended to provide a baseline for improving quality control standards and improving hygiene levels for small manufacturers.

• Food Science of Animal Resources
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• v.38 no.4
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• pp.664-678
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• 2018

This study was carried out to establish shelf life for pork cutlet of ground meat and pork lard by using various quality indicators and to understand how quality changes in these products are accelerated by temperature. The samples were selected and purchased from markets in Korea, and the chosen quality indicators were total aerobic counts and coliform group in microbiological analyses, thiobarbituric acid reactive substances assay, volatile basic nitrogen, pH, acid value, and peroxide value in physical chemical analyses, and sensory evaluation. The pork cutlet samples were stored at $-18^{\circ}C$, $-6^{\circ}C$, and $-1^{\circ}C$, whereas pork lard samples were stored at $10^{\circ}C$, $25^{\circ}C$, $35^{\circ}C$, and $45^{\circ}C$. These temperature conditions were set to real distribution conditions. The samples were then analyzed using various models including of reaction orders, arrhenius equation, and $Q_{10}$ value. The quality limits for each sample were calculated, and shelf life was estimated. The results of this experiment highlighted the importance of temperature control during the distribution process of these products and revealed that temperature is a useful parameter for the establishment of a basic database for shelf life.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.3
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• pp.213-216
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• 2009

Since adopting 1969 CLC and 1971 FC, IMO increased maximum amount of compensation by adopting protocols of 1969 CLC and 1971 FC. Recently IMO adopted 2003 Supplementary Fund by which the compensation limits increased dramatically to 750 million SDR. Korea government has only entered 1992CLC/FC. However, since the Hebei Spirit incident in 2007, there have been strong claims that Korea government should enter 2003 Supplementary Fund. In this article, feasibility study was carried out to help Korea government decide whether or not entering the Convention. The quantitative analysis has been carried out using data of the past oil spill accidents and contribution fee to IOPC Fund and showed that the benefit was much bigger than costs. The qualitative analysis in relation to resources fix compensation to victims, benefits of consignee, and the status of Korea in IMO also showed that Korea should ratify the 2003 SF.

• Journal of Food Hygiene and Safety
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• v.20 no.1
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• pp.36-42
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• 2005

The purpose of this study is to develope a HACCP model for Korean traditional cookies. Prerequisite program and HACCP plan were proposed and analyzed for Yugwa. After analysing hazards of raw material and manufacturing processes, CCP, CL and control methods were presented. Pathogenic microorganisms were detected at the Korean traditional cookies plant. It gave a clue that general sanitation control procedures should be implemented for safe traditional cookie products. Hazard analysis of raw materials and processing of Korean traditional cookies, determination of critical control points and critical limits at the plant lead to present a model of HACCP plan. Implementation of HACCP can be carried out using a HACCP model. Critical control point of Yugwa production were determined as frying process. Biological and chemical hazards were presented for CCP determination.

• The KSFM Journal of Fluid Machinery
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• v.19 no.3
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• pp.14-18
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• 2016

The power generation system using cold energy, which evolves in a large amount during the vaporization process of the liquefied natural gas, was designed in favor of the Rankine cycle with a mixed refrigerant as the working fluid. In this study it is intended to identify the allowable limits of the working fluid composition in respect of equipment safety in the Rankine cycle-type power generation system driven by the cold energy. The thermodynamic properties of the working fluid, which is a hydrocarbon mixture, were calculated with the Peng-Robinson model. In the steady state simulation of the power generation system by using a commercial tool Aspen HYSYS, the feed conditions of LNG Test Bed Train No.1 along with some necessary assumptions were incorporated. The results indicated that deterioration of the mechanical performance of the equipment as well as its safety would be brought about if contents of $C_2H_6$ and $C_3H_8$ in the mixture become, respectively, too high or too low.

• Journal of Food Hygiene and Safety
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• v.8 no.1
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• pp.25-35
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• 1993

This study is conducted to deyelop more conyenient simultaneous determination method by HPLC for mixed antimicrobial agents (sulfamerazine; SMR, sulfamethazine; SMT, sulfamonomethoxine; SMMX, sulfadimethoxine; SDMX, sulfaquinoxaline; SQX, furazolidone; FZ, zolene; ZOL and ethopabate; EPB in muscles of boline, pork and chicken. The drugs were extracted by dichloromethane and water. The extract, after solyent eyaporation, was partitioned in hexane/water and water/dichloromethane. The dichloromethane layer was filtrated with anhydrous $Na_5S0_4\;in\;_3G_3$ glass filter and was eyaporated to dryness. The residue was dissoIYed in mobile phase. The test solution analyzed by HPLC. The chromatograpic conditions were as follows; Column-Spheri 5 RP-8($4.6{\times}220,\;5\;{\mu}$), Wayelength-270 nm, Mobile phase-acetonitrile: 0.005 M oxalic acid (22 : 78). The ayerage recoyeries of drugs from muscles of boline, pork and chicken spiked standard solution were approximately 74~99%, 73~99% and 75~96%, respectiyely. The limits of detection were 5 ppb for SMR, SMT, SMMX, SDMX and EPB, and 8 ppb for SQX, FZ and ZOL.

• Journal of Food Hygiene and Safety
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• v.12 no.4
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• pp.281-287
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• 1997

We have reported a sensitive, specific and simple direct competitive ELISA method to detect aflatoxin in agricultural commodities. We evaluated the ELISA for practical use to detect aflatoxins contaminated in the domestic and foreign agricultural commodities. The detection limits of the direct ELISA for residual aflatoxins in rice, pine nuts, corns, almonds, bean nuts, and pistachio were 10 ppb and in peanuts and cashew nuts were 20 ppb, which were elucidated from the standard curves of ELISA for aflatoxin fortified into the agricultural commodities. Residue studies of naturally contaminated aflatoxins in the agricultural commodities were also carried out by using direct ELISA. As the results of the studies, it was revealed that there were no residues of aflatoxins in 20 rice samples produced in south Korea, 20 pine nut samples in south Korea (9 samples), USA (1 sample) and China (10 samples), each of 20 almond, pistachio and bean nut samples in USA. However, aflatoxin residues were detected in corn samples imported from north Korea (350∼585 ppb in 2 of 3 samples), from USA (109*326 ppb in 6 of 6 samples) and domestic corns (61-326 ppb in 7 of 17 samples). The toxins were contaminated in corn imported from USA for popcorn (17∼20 ppb, in 3 of 10 samples) whereas no residues were detected in corn from south Korea and China. In case of cashew nuts imported from India, 11.4∼23.1 ppb of aflatoxins were detected in 4 from 20 samples. Most of the contaminated foods were harvested before 1995. Thus, hygienic managements of the foods should be required during storage and circulation at market.

• Fire Science and Engineering
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• v.27 no.6
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• pp.64-69
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• 2013

The Numerical simulation was performed on the flow field around the two-dimensional rectangular bluff body in order to simulate an engine nacelle fire and to complement the previous experimental results of the bluff body stabilized flames. Fire Dynamic Simulator (FDS) based on the Direct Numerical Simulation (DNS) was employed to clarify the characteristics of reacting flow around bluff body. The overall reaction was considered and the constant for reaction was determined from flame extinction limits of experimental results. The air used atmosphere and the fuel used methane. For both fuel ejection configurations against an oxidizer stream, the flame stability and flame mode were affected mainly by vortex structure near bluff body. In the coflow configuration, air velocity at the flame extinction limit are increased with fuel velocity, which is comparable to the experiment results. Comparing with the isothermal flow field, the reacting flow produces a weak and small recirculation zone, which is result in the reductions of density and momentum due to temperature increase by reaction in the wake zone.

• Journal of Food Hygiene and Safety
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• v.26 no.1
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• pp.12-15
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• 2011

A method based on high-performance liquid chromatography (HPLC) with ultraviolet detection has been developed to quantify coenzyme Q10 (CoQ10) in raw materials and dietary supplements. Single-laboratory validation has been performed on the method to determine linearity, selectivity, accuracy, limits of quantification (LOQ) and repeatability for CoQ10. An excellent linearity (r=0.999) was observed for CoQ10 in the concentration range $15.625{\sim}500\;{\mu}g/ml$ in dietary supplement. Observed recovery of CoQ10 was found to be between 98.33 and 99.38%. LOQ was found to be $250\;{\mu}g/ml$ Repeatability precision for CoQ10 was between 0.15 and 0.21% relative standard deviation (RSD). Further, limited studies showed that some adulterants and degraded material could be satisfactorily separated from CoQ10 and identified.