• Title/Summary/Keyword: heat-damage

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Effects of Hot Isostatic Pressing on the Microstructure and High-Temperature Fatigue Life of the Ni-base Superalloy IN738LC (IN738LC 초내열합금에서 미세조직과 고온 피로수명에 미치는 고온등압압축(HIP) 공정의 영향)

  • Choi, Cheol;Kim, Doo-Soo;Lee, Young-Chan;Park, Young-Kyu;Kim, Gil-Moo;Kim, Jae-Cheol
    • Korean Journal of Materials Research
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    • v.10 no.2
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    • pp.128-137
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    • 2000
  • A study has been made to investigate the effects of hot isostatic pressing(HIPing) on the microstructure and high temperature fatigue lives of the IN738LC, Ni-base superalloy used in turbine blades, with emphasis on the elimination of casting microporosity and fatigue damage through HIP treatments. Microstructure was observed using OM, SEM and the fatigue life was investigated with rotate bending fatigue tester. The results show that the fatigue lives of properly HIP-processed specimens could be extended be extended by a factor of about sixty. In contrast, no comparable life improvement was achieved with heat treatment only. The repetitive HIP treatment was shown to be very effective as a means of rejuvenating the fatigue life of intentionally fatigue-damaged IN738LC by restoration of the initial alloy microstructure and additional removal of fine casting defects which remained in the HIP-processed material.

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Elucidation of Cause of Cotyledon Black-Decay of Soybean Sprout by Bean Bug, Riptortus clavatus

  • Lee, Jung-Han;Han, Ki-Soo;Kim, Dong-Kil;Kang, Jin-Ho;Kim, Hee-Kyu
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.53 no.3
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    • pp.303-307
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    • 2008
  • Cotyledon Black Decay (CBD) on soybean sprout mimics the black spot due to microbial infection. CBD, not visible or predictable at seedlot state, for some reason, shows up exclusively on cotyledon of soybean sprout during sprouting process. Such an incidence rate fluctuated from 0.8 to 19.5% over three years from 2004. We suspected some pod-infecting anthracnose fungi and/or pod-blight pathogen, or pod-sucking bean bug, one of the major pests of soybean, might have involved, of which we ruled out fungal pathogen because it was preventable through heat treatment, a proven method for seedlot disinfestation. The healthy seeds artificially fed by bean bug for one to seven days were sprouted, and 6 to 41% of the soybean sprout revealed the CBD mimic to those occurred in soybean sprout from previous commercial seedlot screening experiments. This finding is the first report to confirm that bean bug damage to pod at $R_8$ stage is directly responsible for the CBD, which did not concur with any other deleterious effects on sprouting such as reduction in hypocotyls elongation and rooting except unsightly sprout quality. However, earlier feeding either at green pod or greenish yellow pod stage ($R_6$ -early $R_7$ stage) resulted in rather severe damages, which strikingly reduced hypocotyls growth to about one forth to about two third, as well as the reduction in rates of seed germination.

A Study on the Fire Characteristics of Aluminum Composite Panel by Large Scale Calorimeter (라지스케일 칼로리미터에 의한 알루미늄 복합패널 외장재의 연소특성에 관한 연구)

  • Yun, Jung-Eun;Min, Se-Hong;Kim, Mi-Suck;Choi, Sung-Bok
    • Fire Science and Engineering
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    • v.24 no.2
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    • pp.89-96
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    • 2010
  • In this research, exterior material combustion experiment was really tested to evaluate fire risks of aluminium complex panel which is used a lot for building exterior material. As a result, We saw fast fire spreading of aluminium complex panel. The reason is polyethylene in aluminum complex panel combust spreading fast fire flame vertically. In this test, the highest heat release rate of aluminum complex panel was 1,144 kW and surface temperature which is measured by thermocouple went up to more than $903.3^{\circ}C$, that temperature is quite a higher than $660^{\circ}C$ which is aluminum melting temperature. So, fire of aluminum complex panel can be evaluated to give us severe damage both by fast fire spreading vertically and by fire spreading through openings internally. These results from real experiment will be able to use to predict fire spreading of aluminum complex panel by comparing to modeling materialization of aluminum complex panel in the future.

Development of a Coping Scale for Emergency Situations with Elementary School Students (학령기 아동의 응급상황에 대한 대처 측정도구 개발)

  • Kim, Shin-Jeong;Lee, Jung-Eun;Kang, Kyung-Ah;Song, Mi-Kyung;Lee, Sook-Kyung;Kim, Sung-Hee
    • Child Health Nursing Research
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    • v.15 no.3
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    • pp.271-281
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    • 2009
  • Purpose: This study was conducted to develop an instrument to measure coping in emergency situations. Methods: The process included construction of a conceptual framework, generation 60 primary items, verification of construct validity and extraction of final items. The.60 preliminary items were reviewed for content validity by seven experts and were tested to evaluate inter-item correlation coefficient by three groups of elementary school students. From November 1 to December 10, 2008, data were collected from 920 elementary school students according to residential characters (major city, small town, rural area). Item analysis, factor analysis with rotation Varimax and Cronbach's alpha were used to analyze the data. Results: 1) There were 45 items in the final instrument categorized into 8 factors. 2) The factors were labeled as "Call for help and check" (8 items), "Care for common symptoms" (6 items), "Appropriate response for the situation" (5 items), "Evacuation" (6 items), "Care for tissue damage" (8 items), "Care for injury by heat, cold or foreign body" (6 items), "Offer help" (4 items) and "Rescue & escape" (2 items). 3) Cumulative percent of variance was 53.10% and eigen values ranged from 1.04 to 13.38. 4) Cronbach's alpha for the total was .943 and ranged from .527 to .869. Conclusion: Validity and reliability of the scale are confirmed in this study showing its utility for measuring coping in emergency situations with elementary school students. Utilization of the scale will also contribute to designing appropriate coping education programs for elementary school students.

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Characteristics of Icing Phenomenon on Injector in a Liquid Phase LPG Injection SI Engine (대형 액상분사식 LPG엔진 인젝터의 아이싱 특성연구)

  • Kim, C.U.;Oh, S.M.;Kang, K.Y.
    • Journal of ILASS-Korea
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    • v.8 no.2
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    • pp.1-6
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    • 2003
  • The liquid phase LPG injection (LPLI) system (the third generation technology) has been considered as one of the next generation fuel supply systems for LPG vehicles, since it has a very strong potential to accomplish the higher power, higher efficiency, and lower emission characteristics than the mixer type(the second generation technology) fuel supply system However. when a liquid LPG fuel is injected into the inlet duct of an engine, a large quantity of heat is extracted due to evaporation of fuel. This leads to freezing of the moisture in the air around the outlet of a nozzle, which is called icing phenomenon. It may cause damage to the outlet nozzle of an injector or inlet valve seat. In this work, the experimental investigation of the icing phenomenon was carried out The results showed that the icing phenomenon and process were mainly affected by humidity of inlet air instead of air temperature in the inlet duel. Also, it was observed that the total ice formed around the nozzle weighs at about $150mg{\sim}260mg$ after injection for ten minutes. And some fuel species were found in the ice attached at the front side of a nozzle, while frozen ice attached at the back of a nozzle was mostly' consisted of moisture of inlet air. Therefore, some frozen ice deposit. detached from front nozzle of an injector, may cause a problem of unfavorable air fuel ratio control in the small LPLI engine.

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A Study on the Prediction of Fire Load in case of a Train Fire (철도 차량 화재시 화재강도 예측을 위한 연구)

  • Yang, Sung-Jin;Chang, Jung-Hoon;Gang, Chan-Yong
    • Proceedings of the KSR Conference
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    • 2008.06a
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    • pp.2101-2108
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    • 2008
  • Most of train fires which occur in usual cases do not grow up significantly on a large scale enough to bring about casualties and harmful damages. However, the consequence of some train fire accidents can be devastating disaster so that it would be even recorded in history in unusual cases. Accordingly, such a probability of fire disaster cannot be ignored in aspect of the railway safety assesment. A scale of injury and damage is very difficult to predict and analyze. Because it is depend on various factors, i.e. fire load, burning period, facilities, environment condition, and so on. Thus, a prediction of fire load could be understood as a one methodology to estimate railway safety assesment. The summation method which is one of them is used to evaluate the overall fire load by assuming that sum of heat release rate per unit area or mass of each composite material equals the total. However, since the train fire is classified into a compartment fire in under-ventilation condition. The summation method do not estimate a fire load completely. In this journal, Various methods to predict fire load are introduced and evaluated. Especially the fire simulation tool FDS(Fire Dynamics Simulator)which is based on the CFD(Computational Fluid Dynamics) is introduced, too. Through the FDS simulation, numerical analyses for the fire load and flame spread are performed. Then, these results of the simulation are validated through the comparison study with the experimental data. Then, limitations and approximations including in simulation process are discussed. The future direction of research is proposed.

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Damage Factor Interpretation and Conservational Environment Assessment by Microclimatic Analysis of Hyeonpung Seokbinggo (Ice-storing Stone Warehouse), Korea (현풍석빙고의 미기후 분석을 통한 손상요인 해석과 보존환경 평가)

  • Kim, Ji-Young;Lee, Chan-Hee
    • Journal of Conservation Science
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    • v.26 no.4
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    • pp.385-395
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    • 2010
  • This study aimed to identify weathering factors and to assess the conservation environment through microclimatic analysis of Hyeonpung Seokbinggo (ice-storing stone warehouse). The stone blocks inside Seokbinggo suffered crack, displacement, break-out, exfoliation, efflorescence, brown and black discoloration, and biological colonization. Biological colonization represented the maximum deterioration rate(24%) among those weathering forms. The indoor microclimate showed parallel patterns with outdoor one, but the indoor temperature and relative humidity ranged far narrower than outdoor and remained steady. The environmental characteristics resulted from blocking-out of outdoor heat by the closed entrance and surrounding microtopography. This prevented water condensation and freezing effects, so that it reduced physical deterioration of rock, and maximized ice-storing effect for long time. However, contrary to positive effect, extremely high relative humidity over 99% accelerated biological colonization inside the Seokbinggo.

Study on the Principles of Prescriptions of Fire and Heat of Saam Acupuncture (사암침법(舍岩鍼法)의 화열(火熱)에 대한 연구)

  • SaGong, Hee-Chan;Kim, Byung-Soo;Kang, Jung-Soo
    • Journal of Acupuncture Research
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    • v.22 no.4
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    • pp.131-141
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    • 2005
  • Objectives : Saam acupuncture has evident principles of prescription based on acupuncture tonification and purgation of Nan-gyeong but many prescriptions of Saam acupuncture are not typical patterns. This paper studies principles of prescriptions of the king fire and the premier fire. Methods : Through investigation of many medical documents concerning king fire and the premier fire, the author explained of physiological and pathological principle of king and the premier fire, also explained of interacting mechanism through five element. And The theoretical authorities of analysis are Nan-gyeong, works of Joo dan-gye and Li dong-won. Results & Conclusion : 1. The sufficiency and the control of the water is the key to treat the disease by fire. Considering the attack and the treatment of disease, heart and liver give rise to fire in its early stage and kidney and lung are the key to treatment. 2. Consequently the pathology of the disease from fire is corresponding to the theory- Yang Sufficient, Yin Deficient- of Joo dan-gye. It seems that the theory of Joo dan-gye influenced on the medical theory of Saam Acupuncture. 3. On that account I believe that the study of medical theories of the Geum and Won Dynasty that various medical theories had appeared is very available for Saam Acupuncture. At present global warming is accelerating because environmental pollution has been increasing. Therefore the damage of fire to human body will be more and more severe and extensive. Because in the future medical plants will not be free from environmental pollution, acupuncture will be very confidential treatment.

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Influence of Forest Fire on Soil Microarthropod Fauna (산불이 토양 미소절지동물상에 미치는 영향)

  • Choi, Seong Sik
    • The Korean Journal of Ecology
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    • v.19 no.3
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    • pp.251-260
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    • 1996
  • The effect of forest fire on soil microarthropod fauna was investigated in the Inhoo Park, located at Deokjin-gu, Chonju city, where fire burned about 2 hectares on April 5, 1994. Vegetation of the area was covered with mixed forest such as 20 to 30 year old black locust, alder, and pine gree, etc., and also rich in understory plants, dead leaves, twigs, etc. The soil samples were taken from burnt soil and near-by control site on April 10, June 6 and Oct. 22 in 1994, and June 26, 1995. Soil microarthropods were extracted using Tullgren apparatus for 72 hours. Soil microarthropods collected in this experiment were 8, 013 at control and 3, 805 at the burnt site making a total of 11, 818 from 5 classes. Therefore, appearance of microarthropods was reduced to 52.5% at burnt site. Dominant animal groups were Acari (45%) and collembola (46%). The reduced rate of soil animal density by fire damage was 52.5% of the total soil microarthropods accounting 36% in Acari and 70% in collembola. The reduction of soil animal density by fire was 65.3% by habitat destruction and 51.7% by diret shock from fire heat. In Collembola, 89% was reduced by habitat destruction. Oribatid mites collected at sample plots included 29 families, 47 genera and 58 species. Forty-two species at burnt site and 47 species at unburnt site were identified, of these 32 being common species at both sites. The density ratio of soil animals at the burnt sites and those at unburnt sites was 38.6% va 61.4% resulting in 37% reduction due to fire. The dominant species with more than 5% in relative density were Trichogalumna nipponica (7.3%) and Eremobelba japonica (5.8%) at unburnt site, shereas 5 species including Eohypochthonius crassisetiger (8.5%) at the burnt site. The number of these species were 32.1% of total number. MGP analysis based on the number of oribatid mites indicated GP type at both unburnt and burnt sites, revealing domination of the P group in oribatid mites.

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Safety Evaluation of a Shipping Capsule for Special Form Radioisotope (특수형 방사성 동위원소 운반캡슐의 안전성 평가)

  • Lee, Ju-Chan;Seo, Ki-Seog;Ku, Jeong-Hoe;Bang, Kyoung-Sik;Han, Hyon-Soo;Park, Seong-Won
    • Journal of Radiation Protection and Research
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    • v.26 no.1
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    • pp.35-43
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    • 2001
  • All of sealing capsules to transport a special form radioactive material should be designed and fabricated in accordance with the design criteria prescribed in IAEA standards and domestic regulations. The objective of this study is to demonstrate the safety of a shipping capsule for $^{192}Ir$ special form radioisotope which produced in the HANARO. The safety tests were carried out for the impact, percussion, bending and heat test conditions. And leakage tests were carried out before and after the each test. Also, the safety analyses wert performed using computer codes in order to verify the test results. The capsule showed slight scratches and deformation, and maintained its structural and thermal integrities in all tests without any severe damage or melting. It also met the allowable limits of leakage rate after each test. Therefore, it has been verified that the capsule was designed and fabricated to meet all requirements for the special form.

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