• Fire Science and Engineering
• /
• v.26 no.3
• /
• pp.106-111
• /
• 2012

In this study, EIFS (Exterior insulation finish system) of exterior cladding was applied Cone calorimeter test to confirm the effect of flame retardant. As a results, the initial ignition points in accordance with the coated form and concentration of the flame retardant was delayed. But flame resistant treatment of EIFS cladding to control the fire will not affect confirmed that. In addition, EIFS that uses high-density and low-density due to difference in the density of the impact of the fire was no difference. The exterior of the ignition experiment occurred before and after 40 seconds, heat release rate to 100 seconds appears to occur about 90 % compared with the other exterior wall materials, the initial fire spread very fast was confirmed. EIFS cladding in order to prevent the spread of fire in the application of EIFS legally use is limited by the use of the building. And flame spread can be prevented, such as a vertical outer wall compartment measures are urgently needed.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.6
• /
• pp.1163-1168
• /
• 2011

Most transformers use insulating and cooling fluids derived from petroleum crude oil, but mineral oil has some possibility of environmental pollution and fire with explosion. vegetable oil fluids extracted from seed has superior biodegradation and fire-resistant properties including an exceptionally high fire point enhancing fire safety. In this study, it is aimed at the practicality of substituting natural ester dielectric fluid for mineral oil in liquid insulation system of transformers. As a rise in coil winding temperature has a direct influence on transformer life time, it is important to evaluate the temperature rise of coil winding in vegetable oil in comparison with mineral oil. Four transformers for the test are designed with 10KVA, 13.2KV, one phase unit. The temperature are directly measured in insulating oil of these transformers with the two sorts of natural ester and mineral oil dielectric fluid respectively. Experiment for aging carry out two means. First means remained $120^{\circ}C$ that transformer of mineral oil were operated at 185% load. Second means is that insulating oils of two natural ester and mineral oil were aged by thermal cycles repeating from $30^{\circ}C$ to $120^{\circ}C$. For the heating, Transformers were operated at 185% load. For the cooling, cooling system was operated in the chamber. Samples were analyzed at 42, 63, 93, 143, 190, 240 300cycles. Analysis contents are dielectric strength, total acid value. Mineral oils compared results of first means with results of second means. And compared two sort natural esters respectively with mineral oil in second means.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.377-380
• /
• 2008

The material and mechanical properties in the high temperature area of 40 to 100 MPa high strength concrete structural member was identified based on mixing of fiber cocktail and the structural element fire behavior simulation through the finite element analysis method (ABAQUS) was interpreted. The results are as follows. First, it was interpreted that the test specimen with concrete fiber cocktail mixed was more controllable in the maximum shrinkage than the one with concrete fiber cocktail not mixed the controllable range was about 25% to 55%. This means that shrinkage is controllable through mixing of fiber cocktail for the high strength concrete columns. Second, this study didn't consider the explosive spalling by the pore pressure within high strength concrete. If the properties for the pore pressure within high strength concrete is considered and database by strength and by inner temperature of various high strength concrete and steel materials are established in the future, it is interpreted that the technical foundation will be laid for performance based design of fire resistant construction.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.1
• /
• pp.1-6
• /
• 2011

To improve fire-resistance of a high strength concrete against explosive spalling under elevated temperature, fibers can be mixed with concrete to provide flow paths of evaporated water within concrete to the free surface. The fiber-mix concrete approach is effective against explosive spalling when the flow path generated from melting fibers at the elevated temperature is interconnected to transport high pressurized evaporated water from the inside concrete to the free surface. The percolation theory can identify the connectivity of the fibers and provide an estimate of the fire-resistance of concrete by investigating layout of fibers. In this study, the correlation between percolation theory and explosive spalling of fiber-mixed high strength concrete is analyzed and the connectivity of the fiber in concrete is stereologically investigated by using virtual specimens of fiber-mixed high strength concrete.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2021.04a
• /
• pp.23-23
• /
• 2021

Apple (Malus×domestica Borkh.; Rosaceae) is an important fruit crop grown mainly in temperate regions of the world. Tissue culture in vitro is a biotechnological technique that has been used to genetically improve cultivars (scions) and rootstocks. This could be important in the production of genetically uniform scions and rootstocks for commercial apple production. In nurseries, apple plants are produced by grafting scions onto rootstocks. The Cornell-Geneva (Geneva® series) breeding program has bred several dwarf rootstocks that are resistant to diseases and pests and are also cold hardy. This study was conducted to determine the optimal medium strength to improve sprouting shoot rate of apical meristem of the apple rootstocks of fire blight resistance. The apple rootstocks apical meristem at size (0.2 mm to 0.3 mm) with axillary buds were cultured on the MS(Murashige & Skoog) medium supplemented with plant growth regulators. The sprouting ratio and growth characteristics was evaluated after eight weeks in vitro culture. The highest rate of bud differentiation and shoot formation were 23.8% and 55.6%, respectively. After 6 weeks, shoots were regenerated from apical meristem, and their growth characteristics was significantly varied on the respective basal medium with different plant growth regulators. Our studies showed that the apple rootstocks the apple rootstocks of fire blight resistance plantlets could be successfully produced from apical meristem differentiated out of young twigs via organogenic regeneration.

• Korean Journal of Agricultural Science
• /
• v.50 no.2
• /
• pp.241-247
• /
• 2023

Erwinia amylovora , which causes fire blight disease on apple and pear trees, is one of the most important phytopathogens because of its devastating impact. Currently, the only way to effectively control fire blight disease is through the use of antibiotics such as streptomycin, kasugamycin, or oxytetracycline. However, problems with the occurrence of resistant strains due to the overuse of antibiotics are constantly being raised. It is therefore necessary to develop novel disease control methods through an advanced understanding of the pathogenesis mechanism of E. amylovora . To better understand the pathogenesis of E. amylovora , we investigated unknown virulence factors by random mutagenesis and screening. Random mutants were generated by Tn5 transposon insertion, and the pathogenicity of the mutants was assessed by inoculation of the mutants on apple fruitlets. A total of 17 avirulent mutants were found through screening of 960 random mutants. Among them, 14 mutants were already reported as non-pathogenic strains, while three mutants, TS3128_M2899 (ΔSUFU ), TS3128_M2939 (ΔwcaG ), and TS3128_M3747 (ΔrecB ), were not reported. Further study of the association between E. amylovora pathogenicity and these 3 novel genes may provide new insight into the development of control methods for fire blight disease.

• Journal of the Korean Institute of Gas
• /
• v.24 no.4
• /
• pp.18-24
• /
• 2020

The purpose of this study is to validate thermal hinderance effects, i.e., feasibilities, of fire-proof structure for LPG tank exposed to fire from adjacent burning building. The panel materials suggested for the fire-proof structure are (1) 10 mm-thick wood, (2) wood with fireproof coating, (3) 75 mm-thick Expanded Polystyrene, (4) 75 mm-thick glass wool filled sandwich panel, and (5) 75 mm-thick autoclaved lightweight concrete. The square planar fire source of 1 ㎡, a matrix of nozzles releasing 120-140 g/s of LPG, is used to heat up the wall and the tank beyond, mimicking heat transfer from burning exterior wall finishes. The feasibility is tested by inspecting structural integrity after test, and then by examining temperatures at both sides of panels and tank's front surface as well as heat fluxes. As a result, it can be concluded that, among the suggested sample materials, fire-proof wall with ALC panel only showed the feasibility for explosion prevention with the proven evidences of structural integrity and least increase in temperature of tank.

• Research in Plant Disease
• /
• v.8 no.2
• /
• pp.78-83
• /
• 2002

Tobacco diseases have not been recorded until 1900s in Korea, where tobacco plants were introduced at early 1700s. Practical researches on the disease have been conducted since mid 1960s. Major ten tobacco diseases were mosaic caused by tobacco mosaic virus·potato virus Y·cucumber mosaic virus, bacterial wilt, hollow stalk, wild fire caused by angular leaf spot strain, black shank, brown spot, powdery mildew and fusarium wilt. But their annual occurrences were varied according to changes of tobacco varieties and their cultivating practices. As no useful chemicals, several biological tactics have been developed to control the viral or bacterial diseases that give significant economic damages on sustainable crop yield, but not practicable to field farming condition yet. Transgenic tobacco plants containing foreign disease resistant genes have been developed by current bio-technology, but not released to farmers yet. Though some disease-resistant tobacco varieties have been developed by the conventional breeding technology and currently used by farmers, their disease controlling efficacy have been diminished by occurrence of the new strain or race. Future research on tobacco diseases has been focused on technical development to produce high quality tobacco with less production cost, which leads Korean tobacco industry to keep its competence against foreign industry and decreasing overall market.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.13 no.3 s.55
• /
• pp.119-126
• /
• 2009

This study investigated the fire resistance of RC columns applying Fiber addition method, Fire board attaching method, and Fire proof sparying method. The results were summarized as following. The test showed that increase of fiber content, as expected, decreased the fluidity of fresh concrete, but for the types of fiber, the specimens containing nylon(NY) was favorable. The incline of fiber content also affected on the air content of concrete, which the specimens adding polypropylene(PP) fiber was the lowest, followed by a less decrease in polyvinyl alchhol(PVA) and then NY respectively. For the compressive strength at 28days, it was over 50MPa and showed slight increasing tendency by rising fiber contents. After the fire test completed, control concrete exhibited the severe demage, while the specimens containing more than 0.05vol.% of PP and NY was able to protect from spalling. In the case of splay, the partly spalling occurred at the all finishing material, however the RC columns were protected from spalling. For the methods attached with boards, all RC columns were protected except the dry attaching method. The reduced weight ratio was favorable because it was below 8 % except for plain concrete.

• Journal of the Society of Disaster Information
• /
• v.11 no.2
• /
• pp.235-243
• /
• 2015

The methods to improve the protection and explosion-proof performance of concrete structures include the backside reinforcement or concrete material property improvement and the addition of structural members or supports to increase the resistance performance, but they are inefficient in terms of economics and structural characteristics. This study is about the basic study on the fiber composite panel cover, and the nano-composite material and adhesive as the filler, to maximize the specific performance of each layer and the protection and explosion-proof performance as the composite panel component by improving the tensile strength, light weight, adhesion and fire-proof performances. The fiber composite panel cover (aramid-polyester ratios of 6:4 and 6.5:3.5) had a 2,348 MPa maximum tensile strength and a 1.8% maximum elongation. The filler that contained the nano-composite material and adhesive had a 4 MPa maximum tensile shear adhesive strength. In addition, the nano-composite filler was 30% lighter than the normal portland cement