• Title/Summary/Keyword: Thermal movement

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The Measurement of Concrete Deformations at Early Age using Fiber-Optic Bragg Grating Sensors (광섬유 GRATING SENSOR를 이용한 초기재령 콘크리트의 변형 측정)

  • 김지상;이상배;김남식
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10b
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    • pp.1238-1241
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    • 2000
  • The deformations of concrete specimens were measured at early at early ages, in order to verify the applicability of FBG(Fiber Bragg Grating) sensors. The FBG sensors were directly buried at various locations in the beam-type RC specimens at the time of fabrication. In this experiment, the changes of strains in concrete at early age were successfully measured as the movement in wavelength of light signals. The FBG sensors may be a very effective tool to investigate the mechanical/thermal behavior inside of concrete structures.

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Development of Cool-touch Functional Dancesport Top for Middle-aged Women (중년 여성을 위한 냉감기능성 댄스스포츠 상의 개발)

  • Jun, Mi-Hwa;Jang, Jeong-Ah
    • Fashion & Textile Research Journal
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    • v.22 no.5
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    • pp.628-638
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    • 2020
  • This study develops a cool-touch functional Dancesport top for middle-aged women by using cool-touch materials in areas where surface temperature becomes high after exercise. The post-exercise surface temperature of the developed research product was compared and analyzed. In addition, subjective evaluation of cool-touch as well as appearance and movement evaluations were performed. The results are as follows. In designing the research product, a detachable neckband was made using highly-preferred hydrated polymer crystals. A material with high moisture absorption speed was also used in F1, S1, under arm and B5, while a material with good thermal conductivity was used in other parts of the bodice. Deodorant tape with antibacterial and deodorant effects was incorporated in the armpit for additional comfort. As for wear evaluation of the research product, significant differences were found in 10 areas using a material with high moisture absorption speed to compare and analyze the post-exercise surface temperatures of the clothing. The temperature difference between the compared top and the research product in the neckband area was 9.16℃, demonstrating clear cool-touch function in using cool-touch material. In the subjective evaluation of cool-touch function, the results showed high scores when asked about the efficiency of the detachable neckband and the ease of movement when wearing the product. In the appearance evaluation, significant differences were found in 11 items, including redundant folds, tightfit, fit, and design line. The overall mean score of the movement evaluation was 4.6, indicating excellent function for movement.

Wireless Measurement Technology for Power Plant Performance Diagnosis (발전설비의 성능진단 적용 무선계측 기술)

  • Kim, Ui-Hwan;Lee, Eung-Gon;Hong, Eun-Gi
    • KEPCO Journal on Electric Power and Energy
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    • v.3 no.1
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    • pp.9-16
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    • 2017
  • The performance test is conducted for the purpose of determining the accurate thermal performance of the power generation facility or deriving the factors of thermal efficiency degradation. Compared to the acquisition method of power plant thermal performance test data by compensating cable or transmission cable, performance test using wireless instrument can acquire digital data in order to shorten the period due to installation and demolition of instrument and enhance safety of workers and relatively accurate data can be acquired thereby improving work efficiency. Wireless instruments have already been introduced to the market a long time ago, and some of them are used in industry such as petrochemical industry. However, there is no example which has been conducted for performance test of power generation facilities. In order to apply power generation facilities, a reliable system capable of acquiring performance data smoothly without affecting the control system is required. The wireless measurement system can eliminate the measurement defects and errors such as the damage due to the movement of the connecting cable, the extension due to the extension of the shield wire, the contact failure at the contact point between the measuring sensor and the connecting wire, This method has the advantage of collecting relatively accurate performance test data.

A Design of Fire Detection System based on Infrared Thermal Imaging & CCD Camera (적외선 열영상 및 CCD 카메라 기반 화재감지 시스템 설계)

  • Kim, Tae Wan;Choi, Chang Yong;Lee, Dong Myung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2013.05a
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    • pp.597-598
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    • 2013
  • A lot of fire and crime accidents are caused to a significant national loss. For example, the network and power facilities in national industry facilities, the fire risk region in large scale factories such as nuclear and thermal power plants, large-sized buildings, cultural properties, metal and steel mills, chemical plants, oil refineries. The development of a fire detection system that can detects the temperature and movement of objects as high-level quality is essential to prevent these incidents and accidents fundamentally. In this paper, the fire detection system based on infrared thermal imaging & CCD camera id designed to solve these problems.

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An Experimental Study on the Behavior of Muddy Water Lumps Caused by Dropping Soil in Coastal Areas (해역에서 토사침하에 따른 탁수괴 거동에 관한 연구)

  • 신문섭;이종남
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.2 no.4
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    • pp.223-230
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    • 1990
  • Suspended materials during maritime construction works may cause surrounding environmental changes Therefore, it is important to know the behavior of the muddy water lumps caused by dropping soil in coastal areas. Two-dimensional behaviors of the muddy water moving along the inclined boundaries are investigated experimentally, which are the change of height, length, and moving velocity, the properties of movement at the head of muddy water, the coefficient of entrainment and shape, and the accumulation shape. The shape of the muddy water lumps was similar with the slope thermal. Therefore, the moving characteristics were found to be described using turbulence theory.

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Methods in Palaeomagnetism (I) (고자기학(古磁氣學)의 방법(方法) (I))

  • Kim, In-Soo
    • Economic and Environmental Geology
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    • v.17 no.2
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    • pp.141-147
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    • 1984
  • For the discussion of palaeogeomagnetic field direction and the movement and rotation of geotectonic blocks it is prerequisite to eliminate the secondary remanent magnetization component out of the NRM vector of given rock samples. Among various techniques alternating field and thermal demagnetization methods are most easily applicable and most widely used ones. Physical principle underlying these methods is the concept of relaxation time: Either with an action of external magnetic field or with an elevated temperature relaxation time of magnetic minerals can be drastically shortened. It has been furthermore shown experimentally that the secondary remanent magnetization can be more easily demagnetized than the primary remanent magnetization. Through careful stepwise demagnetization it should also be possible to discriminate the kind of various remanent magnetizations. In addition to the introduction to the underlying physical principles and experimental results of the alternating field and thermal demagnetization this paper gives various practical tips in earring out the demagnetization experiments. Each alternating field and thermal demagnetization instrumentation which is easily adaptable to domestic palaeomagnetic laboratories is also introduced. This paper provides a compact and practical introduction to the methods in palaeomagnetism and would be of interest to present workers and to those who want to embark on research in this field.

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Rapid Thermal Annealing at the Temperature of 650℃ Ag Films on SiO2 Deposited STS Substrates

  • Kim, Moojin;Kim, Kyoung-Bo
    • Applied Science and Convergence Technology
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    • v.26 no.6
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    • pp.208-213
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    • 2017
  • Flexible opto-electronic devices are developed on the insulating layer deposited stainless steel (STS) substrates. The silicon dioxide ($SiO_2$) material as the diffusion barrier of Fe and Cr atoms in addition to the electrical insulation between the electronic device and STS is processed using the plasma enhanced chemical vapor deposition method. Noble silver (Ag) films of approximately 100 nm thickness have been formed on $SiO_2$ deposited STS substrates by E-beam evaporation technique. The films then were annealed at $650^{\circ}C$ for 20 min using the rapid thermal annealing (RTA) technique. It was investigated the variation of the surface morphology due to the interaction between Ag films and $SiO_2$ layers after the RTA treatment. The results showed the movement of Si atoms in silver film from $SiO_2$. In addition, the structural investigation of Ag annealed at $650^{\circ}C$ indicated that the Ag film has the material property of p-type semiconductor and the bandgap of approximately 1 eV. Also, the films annealed at $650^{\circ}C$ showed reflection with sinusoidal oscillations due to optical interference of multiple reflections originated from films and substrate surfaces. Such changes can be attributed to both formation of $SiO_2$ on Ag film surface and agglomeration of silver film between particles due to annealing.

Thermal Analysis for Laser Assisted Turning of Square Bar using Laser Heat Source Projection Method (사각형재의 레이저 예열 선삭에서 레이저 열원 투영법을 이용한 열해석)

  • Kim, Jae-Hyun;Choi, Jun-Young;Lee, Choon-Man
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.12
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    • pp.1353-1358
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    • 2011
  • LAT(Laser Assisted Turning) is a method that applies a machining process after softening a workpiece in which a preheating process is locally applied to its machining section using laser heat source. LAT shows several advantages, such as high productivity, reduction of manufacturing cost, high quality. Analysis of temperature distribution after preheating for LAT is very difficult due to its very small heat input area and large energy and its movement. Also, the LAT for a square bar is more difficult because the shape of a laser heat source can be changed according to the rotation of the workpiece. In this study, thermal analysis for LAT of square bar was performed using laser heat source projection method. And, the analysis results were compared with the results of the prior study of numerical calculation method. It is thus shown that the proposed method is efficient for the thermal analysis of a shaped bar.

Consumer recognition and mechanical property comparison of wetsuit material for diving (다이빙용 웨트수트(wetsuit) 소재에 대한 소비자 인식조사와 물성 비교)

  • Sang, Jeong Seon;Oh, Kyung Wha
    • Journal of the Korea Fashion and Costume Design Association
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    • v.20 no.4
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    • pp.163-174
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    • 2018
  • Consumer and property evaluation of wetsuit materials were conducted to obtain useful data for developing competitive products that meet consumer expectations and improving industrial competitiveness. Data were collected through online surveys of 213 domestic consumers who have experienced wearing wetsuit among marine leisure activities. Five types of commercial wet suit materials by brand and four types of commercial wet suit materials with the same quality by thickness were collected. Then, their physical properties, salt water resistance and thermal insulation rate were evaluated and compared. As a result, the most commonly used wetsuit material is 3 to 5 mm thick, and the basic jersey material is bonded on both sides. As a processing for imparting functionality, processing for improving warmth and reducing surface resistance are most frequently used. Consumers often feel uncomfortable when wearing a wetsuit, such as wearing comfort, weight, ease of movement, stretchability, and clothing pressure, which are different from those of casual wear. Also, mechanical strength and warmth were considered to be the most important criteria for selection of wetsuit material for purchase or rental. The mechanical properties of brand A and B were better than those of brand C, D, and E. Resilience and thermal shrinkage were better in brand C, D, and E. On the other hand, there was no significant difference in the physical properties due to the difference in thickness of the material at the same quality. Also, it was found that the thicker the material, the more stable it is in the heat. Brand A and B had superior salt water resistance than brand C, D, and E. In the thermal insulation test, brand A and B showed better insulation characteristics than brand C, D, and E, but the types of bonded fabric and surface finishing of materials were thought to have affected. In comparison of the thickness, the thicker the materials, the better the salt resistance and the thermal insulation.

A Study on Wearing Satisfaction and Thermal Properties of Jumper for Korean Military Tank Drivers (전차병 점퍼의 착용만족도 및 보온성에 관한 연구)

  • Kwon, Seo-Yoon;Choi, Eun-Mi;Lim, Chae-Guen;Shin, Dong-Woo;Kim, Kyung-Pil;Kwon, Oh-Kyung;Jeong, Hyun-Mi
    • Fashion & Textile Research Journal
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    • v.14 no.2
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    • pp.261-268
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    • 2012
  • The purpose of this study is to investigate problems of design, fitness, suitability for movement, and wearing comfort of jumper for Korean military tank drivers through analysis of actual wearing condition by questionnaire and field evaluation and to provide basic data for developing its improved design. The survey was done for 477 military tank drivers and evaluation was performed using thermal manikin to measure insulation. The overall satisfaction for design of jumper for military tank driver was over 3.5(likert scale). The overall satisfaction for fitness of jumper for military tank driver was also over 3.5. The satisfactions for material was between 2.39 and 3.13 and the satisfaction for pilling property was the lowest, followed by static property and shape stability after laundering. The satisfactions for movement suitability were standing(3.81), sitting(3,38), raising hand(forward: 2.90, sideward: 3.01), respectively. In insulation evaluation of jumper for military tank drivers and outwears(jacket, jumper), the insulation of jumper for military tank drivers was lower than outwear(jumper) and same with outwear(jacket). The insulation in dynamic and still condition(without wind) of jumper for military tank driver was 0.37clo and 0.31clo, respectively. Its decreation rate in dynamic condition comparing to still condition was 59% which was lower than jacket(0.73clo) and jumper(1.15clo).