• Title/Summary/Keyword: Testing Equipment

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Girder Distribution Model for Existing Short and Medium Span Steel Girder Bridges (단·중경간 강형교 거더의 횡분배 모델)

  • Eom, Jun-Sik;Nowak, Andrzej S.;Lho, Byeong-Cheol
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.2
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    • pp.219-229
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    • 2003
  • The objective of this work is to verify the Code specified girder distribution factors for short and medium span bridges. To accomplish this objective, field tests were carried out on seventeen simply supported highway bridges. This paper presents the procedure and results of field tests that were performed to verify girder distribution factors. Finite Element analyses previously performed at the University of Michigan indicated that in most cases currently used girder distribution factors specified in AASHTO Codes are too conservative. However, these studies also showed that for short spans and short girder spacings, the girder distribution factors can be too permissive. Therefore, this paper focused on experimental evaluation of girder distribution factors for short and medium span steel girder bridges. The results were compared with the distribution factors specified by AASHTO Standard (2000) and AASHTO LRFD Code (1998). It has been found that the measured girder distribution factors are lower than AASHTO values in most cases, and sometimes the code specified values are overly conservative. The research work involved formulation of the testing procedure, selection of structure, installation of equipment, measurements, and interpretation of the results.

SO2 Removal by Internal Circulation of de-SOx Absorbents (흡수제 내부순환형 탈황장치의 SO2 제거성능 특성)

  • Park, Young-Ok;Park, Hyun-Jin;Kim, Yong-Ha
    • Journal of Korean Society for Atmospheric Environment
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    • v.27 no.6
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    • pp.672-680
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    • 2011
  • Three new granular absorbents were prepared from calcium hydroxide, and applied to an FGD process with internal circulation. The aim of the study was finding the most efficient of the these three applied absorbents for the $SO_2$ removal at high flue gas temperatures. The absorbent is fed to the testing unit at high operation temperature and fluidized inside the FGD system where the sorbent particles react with the $SO_2$ gas. The rate of $SO_2$ decomposition was high in C-type absorbent which had the large surface area. De-SOx characteristics of the current absorbents appeared to be similar to the other conventional agents in this fluidized bed combustor. In particular, the optimum de-SOx condition could be achieved at high mole ratios of Ca to S which can reduce the residual $SO_2$.

A Study on the Standardization of Fineness Measurement for the Thermal Insulator of Military Textiles (방한용 화섬솜의 섬도 측정방법의 표준화에 관한 연구)

  • Hong, Seong-don;Kim, Byung-soon
    • Journal of Korean Society for Quality Management
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    • v.43 no.3
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    • pp.253-272
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    • 2015
  • Purpose: The purpose of this study is to enhance the reliability of quality inspection by standardize the fineness test method of the thermal insulator of military textiles Methods: We have measured the thermal insulator of military textiles by microscope with three different ways and the effectiveness of their difference were analyzed by one-way layout design. Results: We have suggest the standardized the fineness test method of the thermal insulator of military textiles through advanced research. As a result we have verified hollow ratio of heat insulating fiber affect fineness test methods. The fineness test method for the thermal insulator applied with different methods following hollow ratio. We have verified that when the hollow ratio over 90%, the fineness of the thermal insulator measured from fiber-length, if it has over 80%, the cross-section length of hollow and if it has less 80%, the cross-section area of hollow is applied, respectively. Conclusion: This study indicated that the test method of fineness shows high reliability. Heat insulating fibers which have high evenness shows narrow variations(5/% or less, only CV 25%) irrespectively under different testing equipment or institute. Based ons the results, we have suggest the standardization of test methods for fineness by microscope method and produced the registration of Group Standard in Korean Standards Association.

Design for Resonance Avoidance of Mount Through the Modal Analysis (모드해석을 통한 마운트 공진회피 설계)

  • Lee, Jong-Myeong;Yu, Hyeon-Tak;Park, Gyu-Jin;Choi, Hyeon-Cheol;Choi, Byeong-Keun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.25 no.7
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    • pp.481-486
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    • 2015
  • This paper provides how to solve the problems analytically and experimentally that occur for testing the water injection pump under development. First of all, water injection pump, based on shaft system dynamic analysis, is verified by measuring the behavior of the shaft system. After the water injection pump is measured, the structural resonances which can cause excessive noise, degradation the equipment life and malfunction are found. Therefore, by changing the structural design, the reso- nance should be avoided. Application of the design variables to the experimentally resonance avoid- ance is difficult. So analytically, with application of the design variables, the design will be changed with mode analysis using FEM.

A Study on Indications in Radiographic Tests in Welding Specimens According to Shielded Amounts of ATOS 80 High-strength Steel (ATOS 80 고장력강의 보호가스량에 따른 용접부 방사선검사에 관한 연구)

  • Baek, Jung-Hwan;Choi, Byung-Ky
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.6
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    • pp.910-914
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    • 2012
  • In constructing all kinds of equipment and steel structures, discontinuous areas such as weld defects formed in a welded structure tend to generate cracks that will result in damage. In this study, ATOS high-strength steel welding becomes important in butt welding where the tensile strength of the steel is over 80kg/$mm^2$. Structural discontinuities such as joints are more susceptible cracks in part due to their repeated loading and fatigue crack growth. The quality of parts produced depend or the shielded amounts of steel and on the skill of the welders in making strong welds. It is true that there are many factors that can be used to generate a lot of research in this area. However geometry and load conditions due to the combined effects with many issues could be solved through this study. Butt welding material at a plate thickness of 12t in ATOS 80 high-strength steel with a 4 pass, 20l/min, 24V/200A welder is good at making specimens with the quality shown in radiographic testing.

A Study on the Radiograph Inspection of Specimen in Welding Pass Using ATOS 80 High-strength Steel (ATOS 80 고장력강의 용접 패스에 따른 용접부 방사선검사에 관한 연구)

  • Baek, Jung-Hwan;Choi, Byung-Ky
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.6
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    • pp.915-919
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    • 2012
  • In constructing all kinds of equipment and steel structure, parts with discontinuities such as weld defects formed in the welded structure can generate fatigue cracks that results in damage or accidents. In this study, weld zones are investigated with X-rays and the latent images are put on film. Weld zone defects can be verified by developing the film. As weld defects are investigated by radiographic testing and correlated with the welding condition, more appropriate welding conditions can be found. According to the result of X-ray radiographic inspection of butt welding ATOS 80 high-strength steel with a thickness of 12mm, the best conditions for welding without creating weld defects are 4 weld-passes, a protective gas of 20% $CO_2$ and 80% Ar, a protective gas flow of 20L/min, a welding current of 200A, an arc voltage of 24V, a welding speed of 14.4cm/min, a welding rod angle of $50^{\circ}$, a welding gap of 5 mm with a ceramic base, and sand pre-heating to $160^{\circ}$ Celsius prior to welding.

Factors Affecting the Job Performance of Clinical Laboratory Scientists

  • Shim, Moon-Jung
    • Korean Journal of Clinical Laboratory Science
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    • v.41 no.3
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    • pp.140-144
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    • 2009
  • Clinical laboratory testing plays a crucial role in the detection, diagnosis, and treatment of disease. Clinical laboratory scientists evaluate test results, develop and modify procedures, and establish and monitor programs, to ensure the accuracy of tests. It is clear that over the past decade the role of the clinical laboratory scientists has expanded and this process will be continued into the future. The purpose of this study is to clarify the factors influencing the job performance of clinical laboratory scientists and aim to provide the role and duties of clinical laboratory scientists. To examine the frequency of work context and the importance of task, the surveys were conducted on 168 clinical laboratory scientists. The questionnaire items were used 10 score by Likert scale. According to the results of this study, the important factor affecting the job performance was "Analyze laboratory findings to check the accuracy of the results", and the next factors were "Establish and monitor quality assurance programs", "Enter data from analyzer into computer", "Calibrate and maintain equipment". And the factors of "repeating same tasks" and "spend time making repetitive motions" were answered the highest. This study will provide strategies for improving work environment, developing education curriculum and method, and role of clinical laboratory scientists. We must continually upgrade our knowledge, and identify the new trends in technology and science and accept changes.

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KSLV용 추진기관 종합시험설비 개념설계

  • Kang, Sun-Il;Kim, Young-Han;Lee, Jung-Ho;Cho, Sang-Yeon;Kim, Yong-Wook
    • Aerospace Engineering and Technology
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    • v.3 no.1
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    • pp.232-241
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    • 2004
  • KARI(Korea Aerospace Research Institute) is achieving the KSLV program according to National Space Technology Development Program. In this paper, the authors are intend to introduce the Integrated Power Plant(IPP) test facility which will be constructed for the variety of tests on KSLV program. IPP test facility refers to comprehensive testing equipment for liquid rocket launch vehicle. Using this facility, KARI can verify the adaptedness of parts and subsystems for launch vehicle and finally can qualify the system characteristics of launch vehicle doing kinds of test including hot firing test. IPP test facility will make it possible to simulate the vehicle launching circumstances and to predict the performance of launch vehicle during its flight test.

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Comparative Study on the Color Stability of Temporary Prosthetic Materials for Dental CAD-CAM (치과 CAD-CAM용 임시 수복재의 색 안정성 비교 연구)

  • Lee, Hye-Eun;Kim, Won-Soo;Kim, Jung-suk;Lee, Ju-hee;Won, Seuck-Jae
    • Journal of Technologic Dentistry
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    • v.38 no.3
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    • pp.165-173
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    • 2016
  • Purpose: This study was conducted to examine the color stability of temporary prosthetic materials for dental CAD-CAM. Method: 2 kinds of existing acrylic resin temporary filling materials and 2 kinds of polymer prosthetic materials for dental CAD-CAM were used for testing, and five specimens respectively were absorbed in soy sauce, red pepper paste, and coffee. A Chroma Meter was used as analysis equipment. The color change of the specimens was observed to calculate ${\Delta}E$ value throughout 2 days, 3 days, 4 days, and 5 days and this was analyzed and the following result was obtained. Results: Snap's ${\Delta}E$ value was bigger than Vipi block(p<0.05). Red pepper paste had the largest impact on the color change of resin(${\Delta}E$), followed by soy sauce and coffee(p<0.000). With the passage of time, ${\Delta}E$ value was inversely(-) related and decreased somewhat(p<0.000).

Reliable design and electrical characteristics of vertical MEMS probe tip (수직형 MEMS 프로브 팁의 신뢰성 설계 및 전기적 특성평가)

  • Lee, Seung-Hun;Chu, Sung-Il;Kim, Jin-Hyuk;Han, Dong-Chul;Moon, Sung
    • Journal of Applied Reliability
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    • v.7 no.1
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    • pp.23-29
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    • 2007
  • Probe card is a test component which is to classify the known good die with electrical contact before the packaging in the ATE (automatic testing equipment). Conventional probe tip was mostly needle type, it has been difficult to meet with conventional type, because of decreasing chip size, pad to pad pitch and pads size increasingly. For that reason, probe cards using MEMS (micro electro mechanical system) technology have been developed for various semiconductor chips. In this paper, Area Array type MEMS Probe tip was designed,, fabricated, and characterized its mechanical and electrical properties. The authors found that good electrical characteristics under $1{\Omega}$ were acquired with gold (Au) and aluminium (Al) pad contact test over 0.5gf and 4gf respectively. And, contact resistance variation under $0.1{\Omega}$ were achieved with 100,000 times of repetition test. And, insertion loss (IS) for high frequency operation was ascertained over 300MHz at -3dB loss.

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