• Applied Biological Chemistry
• /
• v.50 no.1
• /
• pp.42-47
• /
• 2007

Effect of chlorine dioxide ($ClO_2$) treatment on the microbial and physicochemical changes of fish paste was investigated. Fish paste samples were treated with 5, 10, and 50 ppm of $ClO_2$ solution, respectively, After $ClO_2$ treatment, fish paste samples were individually packaged and stored at 4$^{\circ}C$. The initial microbial loads of samples were 3.8 log CFU/g in total bacterial count, and 2.5 log CFU/g in yeasts and molds. Microbial growth of fish paste during storage showed that populations of total bacteria, yeast and mold were significantly reduced by $ClO_2$ treatment. In particular, the treatment of 50 ppm $ClO_2$ decreased total bacterial count the most significantly among the $ClO_2$ treated fish pastes. The pH and VBN of fish paste decreased with increasing $ClO_2$ concentration. Thiobarbituric acid reacted substance (TBARS) values of treated fish paste increased during storage, regardless of $ClO_2$ concentration. This study showed that 50 ppm chloride dioxide was the optimum dose level to extend the shelf-life of fish paste.

• Weed & Turfgrass Science
• /
• v.3 no.3
• /
• pp.215-220
• /
• 2014

This study was conducted to evaluate potential weed control in organic farming field using false seedbed and stale seedbed techniques. The experiment was conducted in open upland fields during spring and fall crop seasons. The false seedbed was prepared before 2-4 weeks of crop culture and was treated with shallow tillage or flame weeding before transplanting. The weed suppression rates of false seedbed treatment in the spring crop experiments for Chinese cabbage, soybean, hot pepper and corn were 65-73%, 50-55%, 9-55% and 8-33%, respectively. According to crop growth and yield in this experiment, the false seedbed technique has some potential weed control for Chinese cabbage, soybean and corn. The weed suppression rates of stale seedbed treatments in the fall crop experiments for Chinese cabbage, spinach and carrot were 18-39%, 40-77% and 37-38%, respectively. Weed control efficacy of the stale seedbed in this study was lower, when compared with false seedbed.

• Fire Science and Engineering
• /
• v.18 no.2
• /
• pp.20-26
• /
• 2004

The purpose of this study is to investigate the transition mechanism and prevention mechanism of gas explosion to fire. Transition phenomena of explosion to fire of LPG in the explosion vessel of its size of TEX>$100 cm {\times} 60 cm {\times} 45 cm$ was visualized using the high speed video camera and the mechanism was analysed from the videograph. Newspaper size of $30cm {\times} 20cm$ was used for combustible sample in this experiments and LPG-air mixture was ignited by 10 ㎸ electric spark. Experimental parameter was gas concentration, size of vent area and position of combustible solid. Size of vent area were varied as $10cm {\times} 9cm, 13cm {\times} 10cm, 27cm {\times} 20cm, 40cm {\times} 27cm$, and the position of combustible was varied in 4 point. Carbon dioxide was used to study the prevention mechanism of explosion to fire transition of LPG. Based on this experiment we can find that transition possibility of explosion to fire on solid combustible from explosion is depends on concentration of LPG-air mixture and the exposure time of solid combustibles in high temperature atmosphere of flame and burnt gas. And cooling or inerting of the atmosphere after explosion can be prevent the transition of explosion to fire on solid combustibles from gas explosion.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2001.11a
• /
• pp.301-310
• /
• 2001

본 연구는 내화성능을 가진 수막보호유리벽을 실제 건축물에 적용하는데 있어서 필수적으로 고려해야 할 가상시나리오 중에서 수막이 유리면을 보호하기 이전에 유리면에 근접되어 있는 화염으로부터 방출되는 복사열이 유리면이 가열된 상태에서 수막이 형성될 경우 유리면의 온도가 급속히 냉각됨으로서 발생할 수 있는 급냉파열특성을 규명하기 위해 실험한 연구로서 가열면온도범위에 따라 유리면에$150^{\circ}C$이상 $250^{\circ}C$이하에서 수막이 형성될 경우 급냉파열은 일어나지 않았으나 일반유리는 $100^{\circ}C$이상 $150^{\circ}C$이하에서 급냉파열이 일어남을 확인하였다. 즉 방화구획벽에 적용가능한 수막형성유리벽의 유리가 강화유리인점을 착안하면 수막의 도포이전에 강화유리면의 온도가 $250^{\circ}C$까지 올라가기 전에는 수막을 유리면에 접촉하여도 유리면의 급냉파열이 일어나짐 않음을 확인할 수 있었다. 이점은 일정한 구획내에서 유리면의 직근에 설치된 감지기에 의해 수막형성시스템의 가동을 할 경우 급내파열형상이 발생하지 않는 온도범위를 설정할 때 중요한 데이터로 활용가능하다. 결과적으로 국부복사열에 의하여 온도범위를 설정할 때 중요한 데이터로 활용가능하다. 결과적으로 국부복사열에 의하여 유리면의 온도가 급냉파열현상을 일으키는 한계온도에 이르기 전에 유리벽체 상부의감지기의 작동이 필수적으로 일어날 수 있음을 증명한다면 수막을 이용한 유리벽체를 일정시간이상의 내화성능이 요구되는 방화구획의 수직부재로 활용하는데 있어서 걸림돌이 되는 급냉파열에 대한 우려를 종식시키는데 이바지할 수 있다.l류 11.56%, acid류 38.87%, hydrocarbon류 2.89%, ester류 0.80%, 총 70.32%가 확인되었다. Alcohol류에서 linalool가 3.78%, acid류에서는 caproic acid류가 14.40%, carbonyl류에서 2-hydroxy-4-methoxyacetophenone이 2.99%, hydrocabon류에서는 aromadendrene가1.59% 그리고 ester류에서는 methyl palmitate가 0.43%으로 가장 많이 함유하고 있었다.0ppm에서 약 25.6%흡수되었고 ferric citrate 100ppm은 24.7%, ferrous sulfate는 19.7%흡수되었다. ILC를 첨가하지 않은 100ppm 철분염 용액은 ferrous sulfate를 제외하고는 흡수도가 감소되었다. 철분 결핍된 쥐에게 gavage 방법에 의하여 철분강화우유를 투여하였을 때 철분 25ppm 시료에서는 ferrous sulfate가 12.5%로 가장 높았고 ferrous lactate는 8.1%, ferric citrate는 6.5% 흡수되었다. 철분 100ppm수준에서는 흡수율이 낮아져 ferrous sulfate는 25ppm 시료보다 절반이하 수준이었다. Ferric citrate는 차이가 거의 없었으며 ferrous lactate는 70%수준이었다. 이상의 결과에서 철분강화우유에 사용하기 적합한 철분염은 ferrous lactate, ferric citrate였는데 특히 ferrous lactate는 제품의 이화학적 품질, 생이용성 측면 모두에서 가장 좋은 것으로 나타났다.다 높았으며, 1회당 평균 8.1$\pm$5.1개의 난포란을 회수하였다.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.7
• /
• pp.955-959
• /
• 2006

Effects of chlorine dioxide ($ClO_2$) on weight loss, polyphenol oxidase activity, and microbial change of fresh mushrooms (Agricus bisporus Sing) were investigated. Mushrooms were treated with 5, 10, and 50 ppm of $ClO_2$ solution. Mushrooms were stored at room temperature and $4^{\circ}C$. Weight loss for $ClO_2$ treated mushrooms was smaller than that of the control group. Polyphenol oxidase activity of the $ClO_2-treated$ samples stored at room temperature increased until day 2 of storage and then decreased, and the activity of the samples stored bacteria, yeast and mold counts than the control during storage. Aerobic bacterial counts for 50 ppm of $ClO_2$ treatment at $4^{\circ}C$ increased from $1.62{\times}10^2\;CFU/g\;to\;1.66{\times}10^7\;CFU/g$ at day 10 of storage, while control groups were from $1.00{\times}10^3\;CFU/g\;to\;3.72{\times}10^8\;CFU/g$. These results indicate that $ClO_2$ treatment could be useful in improving the quality and microbial safety of mushrooms.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.5
• /
• pp.675-682
• /
• 2021

Fire accidents on land and at sea can cause serious casualties; specifically, owing to the nature of marine plants and ships, the mortality rate at sea from suffocation in confined spaces is significantly higher than that on land. To prevent such cases of asphyxiation, it is essential to install ventilation fans that can outwardly direct these toxic gases from fires; however, considering the scale of marine fires, the installation of large ventilation fans is not easy owing to the nature of marine structures. Therefore, in this study, we developed a new concept for fire safety technology to control toxic gases generated by fires from applied direct current (DC) electric fields. In the event of a fire, most flames contain large numbers of positive and negative charges from chemi-ionization, which generates an "ionic wind" by Lorentz forces through the applied electric fields. Using these ionic winds, an experimental study was performed to artificially control the fire smoke caused by burning paper and styrofoam, which are commonly used as insulation materials in general buildings and ships. The experiments showed that a fire smoke could be artificially controlled by applying a DC voltage in excess of ±5 kV and that relatively effective control was possible by applying a negative voltage rather than a positive voltage.

• Journal of the Society of Disaster Information
• /
• v.17 no.3
• /
• pp.617-626
• /
• 2021

Purpose: The purpose of this study is to evaluate the fire srpead risk of building exterior and roofing materials due to the firebrand of forest fire occurring in the urban areas. Method: In order to achieve this research purpose, by selecting building materials used for exterior and roofing materials of buildings, the time to ignition, total heat release, and heat release rate were investigated, and a forest fire firebrand system was established to the possibility of fire spread was confirmed. Result: As a result of the cone calorimeter test, the roofing material had a similar or faster ignition time due to radiant heat compared to the exterior material with the steel plate exposed to the outside, and showed a higher heat release rate and total heat release than the exterior material. Although it was affected by the flammable material, it was confirmed that it did not spread easily due to the limited amount of combustible material, and carbonization marks appeared inside. Conclusion: The cone calorimeter test method has been shown to be useful in understanding the combustion characteristics of building materials by radiant heat, but the fire spread due to a firebrand in a forest fire is directly affected by the flame due to the ignition of surrounding combustibles, so finding a direct correlation with the cone calorimeter method is difficult. It is judged that the roof material may be more vulnerable to the spread of fire due to the fire than the exterior material.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.2
• /
• pp.377-386
• /
• 2021

The A60 class deck penetration piece is a fire-resistant system installed on a horizontal compartment to prevent flame spreading and protect lives in fire accidents in ships and offshore plants. This study deals with approximate optimization using discrete variables for the fire resistance design of an A60 class deck penetration piece using different surrogate models and a genetic algorithm. Transient heat transfer analysis was performed to evaluate the fire resistance design of the A60 class deck penetration piece. For the approximate optimization of the piece, the length, diameter, material type, and insulation density were applied to discrete design variables, and temperature, productivity, and cost constraints were considered. The approximate optimum design problem based on the surrogate models was formulated such that the discrete design variables were determined by minimizing the weight of the piece subjected to the constraints. The surrogate models used in the approximate optimization were the response surface model, Kriging model, and radial basis function-based neural network. The approximate optimization results were compared with the actual analysis results in terms of approximate accuracy. The radial basis function-based neural network showed the most accurate optimum design results for the fire resistance design of the A60 class deck penetration piece.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.6
• /
• pp.111-120
• /
• 2021

When a fire occurs in a commercial building, the evacuation route is complicated and the direction of smoke and flame is similar to that of the egress route of occupants, resulting in many casualties. Performance-based evacuation design for buildings is essential to minimize human casualties. In order to apply the performance-based evacuation design to buildings, it requires a complex fire simulation for each building, demanding a large amount of time and manpower. In order to supplement this, it would be very useful to develop an Available Safe Egress Time (ASET) prediction model that can rationally derive the ASET without performing a fire simulation. In this study, the correlations between fire temperature with visibility and toxic gas concentration were investigated through a fire simulation on a commercial building, from which databases for the training of artificial neural networks (ANN) were created. Based on this, an ANN model that can predict the available safe egress time was developed. In order to examine whether the proposed ANN model can be applied to other commercial buildings, it was applied to another commercial building, and the proposed model was found to estimate the available safe egress time of the commercial building very accurately.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.4
• /
• pp.1-9
• /
• 2021

A60 class deck penetration piece is a fire-resistance apparatus installed on the deck compartment to protect lives and prevent flame diffusion in fire accidents. In case that the A60 piece is newly developed or its initial design is revised, it is important to verify the fire resistance performance using a fire test procedure (FTP) code. In this paper, transient heat transfer analysis was carried out to evaluate the fire resistance design compatibility of the newly devised A60 piece. The analysis results were verified via a fire test. The heat transfer characteristics were also investigated by comparing design specifications, such as diameter, internal configuration, and material type. The analysis was performed using ABAQUS/Implicit, and the fire test was performed according to the FTP code. The fire resistance performance of the A60 pieces satisfied the safety of life at sea convention regulation. The material type was the most important design specification for the A60 piece. Based on the maximum test temperature, the measured temperature of SUS316L material was 25% lower than that of S45C on average. The differences between thermal conductivity and specific heat of each material were 17% and 58%, respectively.