제 2 발표장 : 탄소 / 탄소 복합재 브레이크 디스크의 초음파 비파괴평가에 관한 연구

임광희,정현조,양인영 한국복합재료학회 1998 한국복합재료학회 학술발표대회 논문집 Vol.- No.1

Flow Directions in Gas Assisted Injection Molding When Cavities of Square Flat Plates and Pipes are Involved 2. Development of Time-dependent Flow Model

임광희,홍수현 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.6

NDE characterization and inspection techniques of trailing edges in wind turbine blades using terahertz waves

임광희,김선규,정종안,조영태,우용득,Chien-Ping Chiou 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.10

Terahertz waves (T-ray) were extensively studied for the nondestructive evaluation of the characterization of trailing edges composed with composite materials. The NDE system consisted of both continuous wave (CW) and time domain spectroscopy (TDS). The FRP composites were utilized for both trailing edges of wind energy (non-conducting polymeric composites) and carbon fiber composites with conducting properties. The signals of T-ray in the TDS mode almost resembles that of ultrasound waves; however, a terahertz pulse could not penetrate a material with conductivity, unlike ultrasound. The refractive index (n) was utilized as one of the material properties, so a method was suggested to obtain the “n” in the materials. The data of refractive index (n) were utilized due to obtained data for the trailing edges. The trailing edges were scanned for charactering and inspecting. C-scan and B-scan images were obtained and the optimal NDE techniques were suggested for complicated geometry samples by terahertz radiation. In particular, the penetrating time-of-flight (TOF) of T-ray corresponded with the calculated TOF for the trailing edges with greater thickness (about 70 mm).

The Treatment of Waste-air Containing Mixed Solvent using a Biofilter 2. Treatment of Waste-air Containing Ethanol and Toluene in a Biofilter (Short Communication)

임광희 한국화학공학회 2005 Korean Journal of Chemical Engineering Vol.22 No.2

An experiment for five stages of a biofilter-run was performed to investigate the effect of hydrophilic eth-ophobic toluene and hydrophilic ethanol, respectively, whenwaste-air containing toluene and ethanol was treated by a biofilter. Removal efficiencies of toluene and ethanol began todecrease when inlet load surpassed 90 g/m3/h and 100 g/m3/h consistent with maximum elimination capacities of tol-uene and ethanol, respectively. At the end of the biofilter-run, removal efficiencies for toluene and ethanol were de-creased and maintained at 65% and 40%, respectively. The concentration of toluene at 1st sampling port was raisedby factor of two in the 3rd stage of the biofilter run when the inlet load of ethanol co-feed was increased by 1.5 times,while the process conditions of toluene were maintained the same as those of the 2nd stage of biofilter-run. Accordingto the result of Mohseni and Allen, it may be interpreted that removal efficiency of hydrophobic toluene was affectedby the presence of hydrophilic ethanol when high load of hydrophobic toluene was applied like that of the 1st samplingport of the biofilter. However it was not the case when a low load of hydrophobic toluene was applied like those ofthe 2nd, 3rd and 4th sampling ports since hydrophobicity of toluene is much less that of -pinene. Thus, it may be sug-gested that biodegradation of hydrophobic VOC was interfered by hydrophilic VOC dissolved in the biolayer and thedegree of interference was proportional to the inlet load of hydrophobic VOC as well as that of hydrophilic VOC andwas inversely proportional to the solubility of hydrophobic VOphobic toluene from waste-air can hardly inversely hinder the removal of hydrophilic ethanol in the biofilter when time-evolutions of hydrophilic ethanol concentrations of this experiment were compared with those of the previous experi-ment of biofilter to treat waste-air containing ethanol only.

Advanced T-Ray Nondestructive Evaluation of Defects in FRP Solid Composites

임광희,이길성,양인영,양용준,서영환,David Kuei Hsu 한국정밀공학회 2013 International Journal of Precision Engineering and Vol.14 No.6

Nondestructive testing technique using T-ray (terahertz ray) receives attention these days as a new field of test engineering. In this study, T-ray time-domain spectroscopy was used for inspecting and evaluating physical property and defect characteristics in FRP composite material. Also, general refraction and transmission mode of this T-ray spectrography was used for finding refraction coefficient (n) and for obtaining T-ray image. First, in order to obtain the terahertz ray refraction index, refractive and transmission mode technique was induced, with which refraction index of GFRP composites, balsa and epoxy of wind turbine blade could be obtained. In GFRP and CFRP composites, T-ray propagation faces hindrance by carbon fiber. Accordingly, the authors have analyzed directional dependence between E-field of T-ray and the carbon fiber. Also, evaluating method of wind turbine blade composites having two (2) saw-blade delaminations integrally inserted was presented in this study. It was found that the time of flight of T-ray using T-ray transmission mode technique coincides well with that using refractive index in the wind turbine blade.

SIS-SBS 개질아스팔트 방수시트재 물성 최적화

임광희,Lim, Kwang-Hee 한국화학공학회 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.5

본 연구에서는 방수시트재를 위한 아스팔트의 styrene-butadiene-styrene (SBS)와 styrene-isoprene-styrene (SIS)에 의한 개질에 있어서 자가치유성을 가지는 개질아스팔트 방수시트재의 연화점(softening point), 침입도(penetration), 저온굴곡저항성능(low temperature flexibility), 점도(viscosity) 및 부착성능(adhesion) 등의 물성을 관찰하고, 반응표면분석법(response surface methodology, RSM)을 활용하여 아스팔트 질량 대비 SBS와 SIS의 적정조성을 도출하고 자가치유성을 가지는 개질아스팔트 방수시트재의 물성을 최적화하였다. 고온에서 측정이 수행되는 연화점과 점도는 SBS 또는 SIS의 함량이 증가함에 따라서 유의하게 값이 증가하였다. 그러나 함량 대비 연화점과 점도 증가분은 SBS 경우가 SIS보다 커짐이 관찰되었다. 이러한 원인은 SBS와 SIS의 열적거동의 차이 때문인데, SBS는 고온에서 점도 상승을 동반하는 겔화(gelation)가 되어 가교도가 커지나 SIS는 점도감소를 초래하는 폴리이소프렌 블록의 사슬분리(chain scission) 때문에 사슬꼬임(chain entanglement)이 상대적으로 적어지기 때문이다. 반면에 SIS-SBS 개질아스팔트는 상온에서 측정되는 침입도, 부착성능 및 저온굴곡성능에 대하여, 아스팔트 63 g을 기본으로 SIS 4~5 g과 SBS 8.5 g의 조성에서 최소 탄성거동을 나타내어 최대 침입도 및 최대 부착성능과 최저 저온굴곡성능 값을 보였다. In this study, styrene-isoprene-styrene (SIS)-styrene-butadiene-styrene (SBS) modified asphalt was prepared for waterproof-sheet to measure its properties including softening point, penetration, low temperature flexibility, viscosity and adhesion. Then the properties of SIS-SBS modified asphalt imparted with self-healing were optimized to seek for optimal compositions of SIS and SBS versus asphalt according to response surface methodology (RSM). As the content of SBS or SIS was increased, both properties of softening point and viscosity, measured at high temperature, were increased with a statistical significance. However, the increments of softening point and viscosity per unit content of SBS added, were observed to be greater than those per unit content of SIS added, respectively. It was due to the difference of thermal properties of SBS and SIS at high temperature that the cross-linking degree of SBS was increased by gelation accompanied with the increase of viscosity, while chain-entanglement of SIS was relatively reduced owing to a chain scission of poly(isoprene) blocks causing the decrease of viscosity. To the contrary, SIS-SBS modified asphalt showed a behavior of the least elasticity resulting in both the maximum of penetration and adhesion, measured at room temperature, as well as the lowest low temperature flexibility at the composition of SIS, 4 g and SBS, 8.5 g based on asphalt, 63 g.

가지달린 지방족 폴리에스테르의 제조 및 물성 조사

임광희,임승순,김유신,김우근,유영태 한국고분자학회 2001 한국고분자학회 학술대회 연구논문 초록집 Vol.2001 No.10

폐가스 처리를 위한 개선된 바이오필터의 미생물분포와 압력강하

임광희,이은주,황선용,신준,조재범,위진건 한국대기환경학회 2013 한국대기환경학회 학술대회논문집 Vol.2013 No.8

Flow Direction When Fan Shaped Geometry is Applied in Gas-Assisted Injection Molding: 2. Development of Flow Model and its Predictions

임광희,홍수현 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.1

In part 2 of the paper simplified unsteady-mass (and momentum-) balance equations of melt polymer resinin the cavities of GAIM were proposed, as a time-dependent rule of thumb, to constitute a novel flow model in GAIMunder the configuration of two fan-shaped geometries connected with a gas nozzle. Upon performing a simulation onthem with commercial software (MOLDFLOW), we compared the time evolution of simulated gas penetration lengthswith the those of unsteady trajectory on the gas flow in GAIM by the suggested novel flow model in the fan-shapedcavities in order to check the precision of model-predicted gas penetration lengths as well as the consistency of itspredicted direction. The results by the suggested novel flow model were satisfactory to fit the trajectory simulated withcommercial software (MOLDFLOW).

테라헤르츠파를 이용한 풍력터빈 블레이드 NDE 탐상 평가기법

임광희,김선규,정종안,조영태,우용득 조선대학교 공학기술연구원 2018 공학기술논문지 Vol.11 No.4

Terahertz waves (T-ray) was extensively studied for the NDE (nondestructive evaluation) of characterization of trailing edges for a use of turbines composed with composite materials. The used NDE system were consisted of both CW(Continuous wave) and TDS (Time domain spectroscopy). The FRP composites were utilized for two kinds of both trailing edges of wind energy (non-conducting polymeric composites) and carbon fiber composites with conducting properties. The signals of T-ray in the TDS (Time domain spectroscopy) mode resembles almost that of ultrasound waves; however, a terahertz pulse could not penetrate a material with conductivity unlike ultrasound. Also, a method was suggested to obtain the "n" in the materials, which is called the refractive index (n). The data of refractive index (n) could be solved for the trailing edges. The trailing edges were scanned for characterization and inspection. C-scan and B-scan images were obtained and best optimal NDE techniques were suggested for complicated geometry samples by terahertz radiation. Especially, it is found that the defect image of T-ray corresponded with defect locations for the trailing edges of wind mill.