• Journal of the Korean GEO-environmental Society
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• v.11 no.10
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• pp.15-24
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• 2010

In the case of underground power utilities pipe such as circular pipe, the most difficult problem is low compaction efficiency of the bottom of pipe inducing the failure of utilities. To overcome this problem, various studies have been performed and one of these is CLSM(Controlled Low Strength Materials) accelerated flow ability. But underground power utilities pipe backfill materials is also needed to have good thermal property that can dissipate the heat as rapidly as it is generated. So, in this study, we performed thermal resistancy test for various materials such as sand, weathered soil, clay and mixed soil to analyze the thermal characteristics of CLSM(Controlled Low Strength Materials) with accelerated flow ability for various conditions(water content, unit weight, void ratio, curing time) and to evaluate the applicability for backfill material of underground power utilities pipe. The test results of 16 specimens for thermal resistancy test showed good thermal property that maintained below $85^{\circ}C\;cm/W$.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1258-1263
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• 2010

Backfill material of buried electrical transmission cable should dissipate the heat as rapidly as it is generated, or high temperatures will lead thermal runaway. These problems could raise thermal resistance and recude trasmission efficiency. So Backfill material of buried electrical transmission cable should have not only structual safty but good thermal property. So, in this study, we performed thermal resistancy test for various materials such as sand, weathered soil, clay and mixed soil to analyze the thermal characteristics of CLSM(controlled low strength materials) for water content.

• Nuclear Engineering and Technology
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• v.5 no.1
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• pp.3-12
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• 1973

Some physical and chemical properties of wood-plastic combinations(W.P.C.) made of domestic soft woods such as pinus densiflora, pinus rigida and poplus deltoides were measured. The rates of improvement in properties were roughly proportional to the contents of polymer or polymer mixtures in W.P.C. For the W.P.C. obtained by means radiation curing and containing 80% of polymer or polymer mixture, the hardness and water absorptirity were improved 2.2 times and 4 times those of the original wood, respectively. The improvement of hardness was especially remarkable in the W.P.C. made of pinus densiflora and polystyrene(120%) to show 7 times increased hardness. For the W.P.C. obtained by means of thermal curing and containing 80% of polymer or polymer mixture, the hardness and water absorptivity were improved 2.4 times and 3.4 times those of the non-treated woods, respectively. These data indicate that the properties of W.P.C. prepared by means of radiation curing are not much different from those of W. p. C. prepared by means of thermal curing. Both of acid resistancy and alkali resistancy of the W.P.C. were also improved remarkably in comparison with the non-treated wood.

• Journal of Korean Society of Steel Construction
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• v.27 no.4
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• pp.387-397
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• 2015

The domestic fire resistance performance test is conducted as a prescriptive design method such as quality test. In quality test there are 2 methods, unloaded fire resistance test and fire resistance test under load. In realistic, these tests, however, have problems with expense, time and diversity of structure. This study reviewed fire resistance performance of H-beam flexural member by thermal stress analysis using finite element ABAQUS program. This research is for the performance-based design reviewing applicability of domestic standard. As a result of this study, limit temperatures per each load ratio provied for proper performance of fire resistancy.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.06a
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• pp.81-90
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• 1995

Age hardenable aluminum alloys show high specific strength, good thermal and electrical conductivity as well as lightness, and are typical aircraft materials. High fatigue strength and good resistancy against stress corrosion cracking are also important for aircraft aluminum alloys. Al alloy 7050 has been developed to meet the above mentioned requirements and the use of this alloy as forged aircraft part becomes more important. However, forged 7050 parts showed undersirable structures such as severe local grain coarsening in surface area and unproper metal flow that is degrading mechanical properties. In this paper, microstructural aspects of die forging in the Al alloy 7050 are investigated. Also suggested are the optimal forging conditions for microstructural control of Al alloy 7050.

• 연구논문집
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• s.26
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• pp.113-120
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• 1996

Age hardenable aluminium alloys show high specific strength, good thermal and electrical conductivity as well as lightness, and are typical aircraft materials. High fatigue strength and good resistancy against stress corrosion cracking are also important for aircraft aluminium alloys. Al alloy 7050 has been developed to meet the above mentioned requirements and the use of this alloy as forged aircraft part becomes more important. However, forged 7050 parts showed undersiable structures such as severe local grain coarsening in surface area and unproper metal flow that is degrading mechanical properties. In this paper, microstructural aspects of die forging in the Al alloy 7050 are investigated. Also suggested are the optimal forging conditions for microstructural control of Al alloy 7050.

• Korean Journal of Food Science and Technology
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• v.11 no.3
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• pp.153-156
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• 1979

Spoiled mushroom cans were collected from several canneries and examined the spore bearing bacteria in them. Thirty four isolates of anaerobic mesophiles were isolated. The one isolate(Cl-5) which was the most heat stable among the above isolates, the other isolate (D-29) which was examined in the previous experiment (Korea J. Food Sci. Technol., 10(2), 224 (1978) and PA 3679 were compared their heat resistancy in neutral phosphate buffer. They were confirmed the spoilage of mushroom products. Z value and $D_{250}$ value of the Cl-5(isolated from mushroom casing soil at Gimjae) possessing the highest resistancy were $21.3^{\circ}F$ and 1.8 min in mushroom can (4 oz. piece and stem). It's F value was 8.95 when Z value was 21.3.