• Title/Summary/Keyword: General connection

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Steel Module-to-Concrete Core Connection Methods in High Rise Modular Buildings: A Critical Review

  • Poudel, Bishal;Lee, Seungtaek;Choi, Jin Ouk
    • International conference on construction engineering and project management
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    • 2022.06a
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    • pp.571-578
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    • 2022
  • Modularization in a high-rise building is different from a small building, as it is exposed to more lateral forces like wind and earthquakes. The integrity, robustness, and overall stability of the modules and their performance is based on the joining techniques and strong structural systems. High lateral stiff construction structures like concrete shear walls and frames, braced steel frames, and steel moment frames are used for the stability of high-rise modular buildings. Similarly, high-rise stick-built buildings have concrete cores and perimeter frames for lateral load strength and stiffness. Methods for general steel-concrete connections are available in many works of literature. However, there are few modular-related papers describing this connection system in modular buildings. This paper aims to review the various research and practice adopted for steel-to-concrete connections in construction and compare the methods between stick-built buildings and modular buildings. The literature review shows that the practice of steel module-to-concrete core connection in high-rise modular buildings is like outrigger beams-to-concrete core connection in stick-built framed buildings. This paper concludes that further studies are needed in developing proper guidelines for a steel module-to-concrete core connection system in high-rise modular buildings.

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A Study on Remake of Dental Prosthesis According to Dental Laboratory Characteristics (Focusing on Daegu and Gyeong-buk of Dental lab) (치과기공소의 특성에 따른 치과보철물의 재제작에 관한 연구 - 대구.경북 치과기공소 중심으로 -)

  • Kim, Jeong-Sook;Lee, Hee-Sung
    • Journal of Technologic Dentistry
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    • v.33 no.3
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    • pp.227-236
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    • 2011
  • Purpose: The purpose of this study was to reduce the remake rate of dental prosthesis. We examined remake cause and major factor of dental prosthesis to determine methods for raising dental prosthesis satisfaction. Methods: Subjects included dental technicians in the metropolitan areas of the cities of Daegu and Gyeong-buk. Surveys were filled out by consenting dental technicians. Statistical analysis was done using SPSS version 19.0 for Windows. We determined frequencies and percentage, calculating means, and standard deviations, and determining statistical significance using t-tests, analysis of variance. Results: Impression or material transform is high among remake cause and margin is high among remake major factor. Crown class showed differences in General characteristics associated with age, number of employees, and number of connection dental. Porcelain class showed differences in General characteristics associated with age, number of employees, and number of connection dental. Denture class showed differences in General characteristics associated with age, monthly salaray, and career. Implant class showed differences in General characteristics associated with age, education, and career. Conclusion: In order to reduce remake rate of dental prosthesis, communication of dentist, dental technician, and the patient are require and correct information of patient and dental prosthesis are need.

Seismic response and energy dissipation in partially restrained and fully restrained steel frames: An analytical study

  • Reyes-Salazar, Alfredo;Haldar, Achintya
    • Steel and Composite Structures
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    • v.1 no.4
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    • pp.459-480
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    • 2001
  • The damage suffered by steel structures during the Northridge (1994) and Kobe (1995) earthquakes indicates that the fully restrained (FR) connections in steel frames did not behave as expected. Consequently, researchers began studying other possibilities, including making the connections more flexible, to reduce the risk of damage from seismic loading. Recent experimental and analytical investigations pointed out that the seismic response of steel frames with partially restrained (PR) connections might be superior to that of similar frames with FR connections since the energy dissipation at PR connections could be significant. This beneficial effect has not yet been fully quantified analytically. Thus, the dissipation of energy at PR connections needs to be considered in analytical evaluations, in addition to the dissipation of energy due to viscous damping and at plastic hinges (if they form). An algorithm is developed and verified by the authors to estimate the nonlinear time-domain dynamic response of steel frames with PR connections. The verified algorithm is then used to quantify the major sources of energy dissipation and their effect on the overall structural response in terms of the maximum base shear and the maximum top displacement. The results indicate that the dissipation of energy at PR connections is comparable to that dissipated by viscous damping and at plastic hinges. In general, the maximum total base shear significantly increases with an increase in the connection stiffness. On the other hand, the maximum top lateral displacement $U_{max}$ does not always increase as the connection stiffness decreases. Energy dissipation is considerably influenced by the stiffness of a connection, defined in terms of the T ratio, i.e., the ratio of the moment the connection would have to carry according to beam line theory (Disque 1964) and the fixed end moment of the girder. A connection with a T ratio of at least 0.9 is considered to be fully restrained. The energy dissipation behavior may be quite different for a frame with FR connections with a T ratio of 1.0 compared to when the T ratio is 0.9. Thus, for nonlinear seismic analysis, a T ratio of at least 0.9 should not be considered to be an FR connection. The study quantitatively confirms the general observations made in experimental results for frames with PR connections. Proper consideration of the PR connection stiffness and other dynamic properties are essential to predict dynamic behavior, no matter how difficult the analysis procedure becomes. Any simplified approach may need to be calibrated using this type of detailed analytical study.

A study on the Grounding method for reduce an interference by CATV Transmission Line (CATV 전송선로의 간섭을 줄이기 위한 접지방식에 관한 연구)

  • Hwang, Jong-Sun;Yon, Che-Chin;Park, Sung-Jin;Kim, Yeong-Min
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.57-60
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    • 2001
  • CATV is the abbreviation for Cable Television. General CATV is a way of multi-channel sending images, voices and music including stillness image as well as characters to public receivers through electrical cable communication system. In the beginning, master antennas were people can not receive TV signal well. TV programs were received from master antennas to TVs in each house. Ground connection began by experimenting lightning with the use of a kite and it means electric appliances, communication equipments, measuring instruments and so on connecting the Earth in order to flow away overcharged electricity. There are two kinds of earth connection: Power Ground and Signal Ground. Power Ground is for preventing an electric shock and in general there's no current in the connector. However in an accident, there's a quick flow of electricity out to the Earth. Signal Ground is not only for the safety of appliances but also for the safety of equipment operation. This paper is about connection for noise and interference reduce in order to prevent wrong operation and distortion of signal in the electrical appliances which can take place in CATV.

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A study on the Grounding method for reduce an interference by CATV Transmission Line (CATV 전송선로의 간섭을 줄이기 위한 접지방식에 관한 연구)

  • 황종선;연제진;박성진;김영민
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.57-60
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    • 2001
  • CATV is the abbreviation for Cable Television. General CATV is a way of multi-channel sending images, voices and music including stillness image as well as characters to public receivers through electrical cable communication system. In the beginning, master antennas were people can not receive TV signal well. TV programs were received from master antennas to TVs in each house. Ground connection began by experimenting lightning with the use of a kite and it means electric appliances, communication equipments, measuring instruments and so on connecting the Earth in order to flow away overcharged electricity. There are two kinds of earth connection: Power Ground and Signal Ground. Power Ground is for preventing an electric shock and in general there's no current in the connector. However in an accident, there's a quick flow of electricity out to the Earth. Signal Ground is not only for the safety of appliances but also for the safety of equipment operation. This paper is about connection for noise and interference reduce in order to prevent wrong operation and distortion of signal in the electrical appliances which can take place in CATV.

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Development and Performance Evaluation of the Fourth Generation H-section Beam-to-Column Weak Axis Connection for Improving Workability (시공성 향상을 위한 제4세대 H형강 기둥-보 약축접합부의 개발 및 성능평가)

  • Kim, Pil-Jung;Boo, Yoon-Seob;Yang, Jae-Guen;Lee, Eun-Taik;Kim, Sang-Seup
    • Journal of Korean Society of Steel Construction
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    • v.23 no.3
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    • pp.295-304
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    • 2011
  • Bracket-type connection is often used for the weak-axis steel connection. In general, a beam-to-column connection for the bracket type is fabricated at the shop and abeam splice is additionally attached to the bracket in the site. Therefore, steel construction would not be competitive due to the increase of beam splice fabrication cost and overall construction period. This paper now proposes the new weak-axis connection types without a scallop, which has more definite strength flow, simple connection details, and better workability. From the series of experiments, the proposed connections showed better strength and ductility in comparison with standard details with scallop because the thickness of the welding plate for wide-flanged, beam-to-column connection can be easily adjusted.

A Study on Surface Modeling of Hull forms for General purpose CAD program (범용 CAD 프로그램에서의 응용을 위한 선형 곡면화 방법론에 관한 연구)

  • 이준호;김동준
    • Journal of the Society of Naval Architects of Korea
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    • v.41 no.1
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    • pp.75-81
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    • 2004
  • In this study surface modeling .method with 3D curve net is proposed. For surface modeling, ship hull was divided into several parts, Generated surface was loaded general purpose CAD program through IGES file format, and the quality of generated surface model was checked by CATIA's internal function. Lastly it is tried to find a method for improving the accuracy of surface connection by using the blending method in CATIA and the result was discussed.

Total Anomalous Pulmonary Venous Connection - 1 case report - (총폐정맥 환류이상증;1례 보고)

  • Song, U-Cheol;Kim, Byeong-Ju;Hong, Gi-U
    • Journal of Chest Surgery
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    • v.25 no.12
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    • pp.1465-1470
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    • 1992
  • We experienced one case of total anomalous pulmonary venous connection to coronary sinus with secondum type ASD. The case was 21 years old woman with mild dyspnea on exertion and ill looking appearance. The disease was confirmed by 2D echocardiogram and cardiac catheterization. Under the conventional cardiopulmonary bypass, we repaired the anomaly by use of Dacron patch. The postoperative course was uneventful and discharged with excellent general condition and has been good during follow-up.

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GEOMETRY OF FIELD EQUATIONS ON $MEX_n$

  • Yoo, Ki-Jo
    • Communications of the Korean Mathematical Society
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    • v.16 no.4
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    • pp.637-648
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    • 2001
  • An n-dimensional ME-manifold ME $X_{n}$ is a general-ized Riemannian manifold connected by the ME-connection which is both Einstein and of the form (2.13). The purpose of this paper is to study the properties of the ME-curvature tensors, the con-tracted ME-curvature tensors and the field equations in ME $X_{n}$)n)

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A Study on the Polarity Discrimination Method of the Stator Windings for 3 Phase Induction Motors based on the Residual Magnetism and I Winding Connection (잔류자기와 I 결선에 의한 3상유도전동기 고정자 권선의 극성판별법에 대한 연구)

  • Choi, Soon-Man
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.1
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    • pp.72-77
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    • 2015
  • When connecting 6 lead wires from stator windings to the terminals of 3 phase induction motors for Y or ${\triangle}$ connection, it is feared that the polarities of windings could be reversed each other if the wire tags are lost or erased, resulting in inadmissibly high current to motors in case of starting. To protect motors against such situations, some test procedures are necessary during wire connection which need to be easy ways to electricians without particular tools except a general multi-tester and with less time-consuming in the field. This study focuses on a test measure to satisfy these requirements which is able to provide them a convenient procedure for winding polarity discrimination considering the field condition. Here, the proposed measure utilizes the residual magnetism of the rotor and checks the indication of voltage or current at windings which are induced by the residual flux of rotor when rotating it by hands with 3 stator windings connected in the form of I connection. Principle characteristics and experiment results for this method are analyzed in the view of the effectiveness and applicability for the winding polarity discrimination.