• Title/Summary/Keyword: 유지 조건

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Evaluation of Material Properties of Fire-damaged Concrete Under Post-fire Curing Regimes Using Impact Resonance Vibration Method (충격 공진 기법을 이용한 화재 손상 콘크리트의 재양생 조건별 재료물성 평가)

  • Park, Sun-Jong;Yim, Hong Jae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.5
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    • pp.42-48
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    • 2017
  • When concrete structures expose to fire, the structures were damaged accompanied with degradation of material properties of concrete. In order to determine the reuse of fire-damaged concrete structures, it is needed a careful determination considering conditions of fire damage, such as exposure temperature and exposure time, and also potential to restore fire damage. This study investigates on the evaluation of residual material properties of fire-damaged concrete under different post-fire curing regimes. An experimental study was performed on concrete samples to measure the dynamic elastic modulus by the impact resonance vibration method. Upon the experimental results, the evidence of restoration of material properties was confirmed on specific post-fire curing regimes, higher humidity conditions. Additionally, a correlation analysis was performed on the dynamic elastic modulus with the tensile strength for identifying the effects of post-fire curing regimes on both material properties of fire-damaged concrete.

Preparation Conditions of Hydrolyzed Vegetable Protein Soy Sauce for the Reduction of 3-Monochloropropane-1,2-Diol (3-MCPD) (3-Monochloropropane-1,2-diol(3-MCPD) 저감화를 위한 아미노산 간장의 제조조건)

  • Chung, Yong-Il;Lee, Ji-Soo;Lee, Hyeon-Gyu
    • Korean Journal of Food Science and Technology
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    • v.41 no.5
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    • pp.522-527
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    • 2009
  • The principal objective of this study was to assess the effects of various manufacturing conditions of soy sauce containing hydrolyzed vegetable protein (HVP) (HVP-soy sauce) on 3-monochloropropane-1,2-diol (3-MCPD) contents. Various HVP soy sauces were prepared under different conditions of alkaline treatment and retention process. Derivatives of heptafluorobutylimidazole (HFBI) 3-MCPD were determined via GC/MS below $0.010{\mu}g/g$, which was sensitive with a good recovery rate. The quantity of 3-MCPD decreased with the pH and temperature of alkaline treatment, and the time and temperature of the retention process increased. Alkaline treatment at pH 10.0-10.5 and a 72 hr retention process were shown to reduce effectively the 3-MCPD contents of HVP-soy sauces. This result indicates that the manufacturing process, particularly alkaline treatment, and retention process would be critical steps in managing 3-MCPD contents in HVP-soy sauce.

Effect of Latent Heat Material Placement on Inside Temperature Uniformity of Insulated Transfer Boxes (단열용기의 잠열재 배치에 따른 내부 온도 균일성에 대한 영향)

  • HyungYong Ji;Dong-Yeol Chung;Seuk Cheun Choi;Joeng-Yeol Kim
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.29 no.1
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    • pp.27-33
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    • 2023
  • An optimized design of the transportation insulated box must be considered to control the thermal damage in order to maintain the fresh condition for temperature-sensitive medicine and frozen food safety. The inside temperature of the insulated box is a natural convection enclosure state, thermal stratification naturally occurs as time passes in case of with outside heat load. The latent heat material (LHM) placement inside the box maintains the target temperature of the product for temperature fluctuations during transport, and LHM application is a common and efficient method. In this work, inside temperature stratification in an insulated box depending on the LHM pack position is numerically simulated and experimented. The insulated box is made up of vacuum insulation panel (VIP), and LHM modules are placed over six faces inside the box, with the same weight. The temperature curves for 72 hrs as experiment results clearly show the temperature stratification in the upper, middle, and lower at the LHM melting time region. However, the temperature stratification state is uniformly changed in accordance with the condition of the upper and lower placement weight of the LHM pack. And also, the temperature uniformity by changed placement weight of LHM has an effect on maintaining time for target air temperature inside the box. These results provide information on the optimized design of the insulated box with LHM.

Effects of Tempering Temperature and Time on the Slip Melting Point of Fats (처리 온도 및 시간이 고형 유지의 상승 융점에 미치는 영향)

  • Yi, Young-Soo;Chang, Young-Sang;Shin, Zae-Ik
    • Korean Journal of Food Science and Technology
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    • v.23 no.1
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    • pp.19-24
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    • 1991
  • Among the conditions changes for the slip melting point of tempering temperature and time were studied. The results were treated below at $4^{\circ}C$, slip M.P. were not effected by tempering time. But slip M.P. of lard and palm oil had fallen treated at $10^{\circ}C$, the reason was that low melting triglycerides did not form the perfect crystals. Therefore, in order to measure the slip M.P. should be decrease the free energy and from stable crystallization of fats. Recommendable tempering temperature was treated at $4^{\circ}C$.

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Assessment and Retrofitting of Existing Bridges (기존 교량의 평가 및 보강)

  • Kang, Su Tae;Kwon, Seung Hee
    • Magazine of the Korea Institute for Structural Maintenance and Inspection
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    • v.16 no.2
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    • pp.74-86
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    • 2012
  • 이태리를 비롯한 대부분의 유럽 국가들에 건설된 많은 기존 도로 및 철도 교량들 중에는 현재의 구조설계기준이나 교통시스템, 유지관리비용 절감 등을 고려한 요구조건과 비교했을 때 구조적 안전성과 기능성을 만족시키지 못하는 경우가 종종 있다. 따라서 어떤 형식의 교량이든 특정 취약성을 평가할 수 있는 신속하고 신뢰성 있는 방법론이 필요하다. 이 논문의 앞부분은 이태리 내 도로 및 철도 구조물에 대해 그런 형태의 방법론의 적용에 대해 기술하였으며, 그 결과를 보면, 한 예로 조적조 아치 교량이 일반적으로 상당히 건전한 구조 시스템으로 나타났으며 RC 교량은 일반적으로 내구성 문제를 드러내며 지진하중에 대해서도 취약한 것으로 나타났다. 강교량은 내구성 문제 외에 피로에 특히 취약한 것으로 나타났다. 그리고 이 논문에서 고려한 전형적인 보강기법들에 대해 간략히 소개하였다. 뒷부분에서는 네 개의 기존 RC교량을 중심으로 주요 교량보강 사례연구들에 대해 좀 더 자세히 기술하였다. 이 교량들은 2차 세계대전 이후에 가장 일반적으로 채택되던 형식들 중의 한 예로 보강기법의 일반적 성질을 고찰하는데 있어 적합하다. 교량의 성능개선에 대해서는 방법론적 접근에 대해 개략적으로 나타내었으며, 여기에는 구조물의 유형적 특성, 유지관리 현황, 기능적 요구조건 및 보수 보강 시스템과 연계된 환경적인 면을 고려하고 있다.

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Elicitation of Ecological Wetland's Creating & Maintaining Conditions through GIS & AHP Analysis (GIS와 AHP분석에 의한 생태습지의 생성 및 유지조건 도출)

  • Um, Dae Yong;Shim, Mi Young;Shin, Ke Jong
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.31 no.1
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    • pp.29-40
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    • 2013
  • The object of this research is to elicit the ecological wetland's creating and maintaining conditions through GIS and AHP(Analytic Hierarchy Process) on common characteristics of wetland, by exploring the function of the long-standing and naturally created wetlands in South Han-river basin. Geomorphological, geologic, hydraulic & hydrological, pedological, environmental & ecological approaches of five categorizations were made based on the documents and precedent studies in order to perform the research object. Elicitation of the common creating and maintaining conditions on the objected wetlands through analysis of satisfactory conditions was conducted by performing an overlay analysis from the gathered information in each category and linking its result to each wetland. Also, elicitation of highly believable qualified analysis result was made by calculating the each factor's weight through application of AHP analysis method on each factor. The research result is expected to be applied effectively in suitability selection for creation of an artificial wetland and restoration and maintenance for naturally created wetlands when introducing the No Net Loss of Wetlands. In addition, with a new understanding on wetland and beyond the value of its conservativeness, this research result can be considered as a solution for Eco-Wetland's maintainable development.

Development of Defect-Repair Method-Cost Mapping Algorithm of Concrete Bridge Using BMS Data (BMS 데이터를 활용한 콘크리트 교량의 결함-공법-비용 매핑 알고리즘 개발)

  • Lee, Changjun;Park, Wonyoung;Cha, Yongwoon;Jang, Young-Hoon;Park, Taeil
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.43 no.2
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    • pp.267-275
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    • 2023
  • As aged infrastructures have been increased, the importance of accurate maintenance costs and proper budget allocation for infrastructure become prominent under limited resources. This study proposed a mapping algorithm between representative defects, repair methods, and the estimated maintenance costs for concrete bridges. In this regard, using BMS (Bridge Management System) data analysis, bridge repair methods were classified and matched with defects according to their locations, types, and sizes. In addition, the maintenance costs were estimated based on the amount of work-load and quantity per unit using CSPR (Cost Standard Production Rate). As a result, the level of accuracy was an average of 85.1 % compared with the actual bill of quantity for Seoul bridge maintenance. The accuracy of maintenance costs is expected to be enhanced by considering the various site conditions such as pier height, extra charge conditions, additional equipment, etc.

화학공장용 프로세스 펌프의 특성

  • 이동양
    • Journal of the KSME
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    • v.28 no.1
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    • pp.37-41
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    • 1988
  • 일반적으로 화학공장에서 요구되는 프로세스 펌프는 취급하는 액의 물리적 화학적 성질 및 고 형체(solid)함량, 결정생성 여부 등을 고려 이에 충분히 견디고 유지보수가 용이하며 가격 면에 서도 저렴하고 여러 가지 운전 조건에 상응할 수 있는 호환성 있는 제품이어야 한다. 다양한 액성 및 운전조건에 적합한 펌프 선정에는 실제적인 많은 시험과 경험이 필요하다. 본 글에서는 원심펌프 선정시 보편적으로 고려되어야 할 일반사항에 대하여 기술하고자 한다.

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