• Title/Summary/Keyword: Braces

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Base Pattern Development of Protective Clothing - Focusing on Protective Clothing for Riot Policewomen - (보호복 상의 베이스 패턴 개발 - 여경보호복을 중심으로 -)

  • Kim, Hyo-Sook;Kim, Ji-Hyeon
    • Journal of the Korea Fashion and Costume Design Association
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    • v.17 no.3
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    • pp.207-224
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    • 2015
  • Protective clothing for riot policewomen is worn by policewomen to protect their body at suppressing a riot. Plastic guards of Nylon 66 material are attached to the base of E.V.A. Foam material. Protective clothing for riot policewomen consists of a jacket, guards for arms and legs, upper arm braces, and thigh pads. This study was aimed to develop the base pattern of the jacket to protect the torso and to improve the body suitability and the adaptability to movements of protective clothing for riot policewomen. Since current protective clothing worn by riot policewomen is manufactured with the same design of protective clothing for riot policemen, the body suitability and the adaptability to movements are not very satisfactory for policewomen who has different body structure than from riot policemen. Therefore, the purpose of this study is to reflect the body size and characteristics of riot policewomen and develop the base pattern of protective clothing with better body suitability and adaptability to movements. In this respect, amount and place of dots on the jacket were differently designed, made and evaluated by fitting test. The base with the best evaluation was selected as the final experiment clothing to demonstrate its superiority compared with the existing protective clothing.

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Current Trends in Research on Conservative Treatment of Scoliosis (척추 측만증의 보존적 치료에 관한 최신 지견 - PubMed 검색을 위주로 2008년 이후 -)

  • Cho, Sung Woo;Lee, Seung Yeon
    • The Journal of Pediatrics of Korean Medicine
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    • v.27 no.1
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    • pp.15-25
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    • 2013
  • Objectives Scoliosis is that spine's arrangement was changed to be curved. Mostly scoliosis was found at childhood and recently rate of scoliosis is increasing. Causes of scoliosis were very various, but the patients are due to idiopathic reasons. Scoliosis was treated by conservative treatment or surgery treatment. If scoliosis is diagnosed early enough, it can be treated with conservative treatment. Methods We are searching PubMed by keywords and found 47 theses complied with requirements. Results Studies of conservative treatment of Scoliosis were active. Conservative treatments are considered before surgery treatment and there was a set guideline of conservative treatment. Also, there were several studies about effectiveness of conservative treatment and quality of life, mental stress. Studies about various kinds of conservative treatment were found as well. There were brief studies about introduction of new brace, effectiveness of several braces, and case studies. Conclusions Conservative treatment is very effective choice before surgery treatment at Scoliosis patient.

Direct displacement based design of hybrid passive resistive truss girder frames

  • Shaghaghian, Amir Hamzeh;Dehkordi, Morteza Raissi;Eghbali, Mahdi
    • Steel and Composite Structures
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    • v.28 no.6
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    • pp.691-708
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    • 2018
  • An innovative Hybrid Passive Resistive configuration for Truss Girder Frames (HPR-TGFs) is introduced in the present study. The proposed system is principally consisting of Fluid Viscous Dampers (FVDs) and Buckling Restrained Braces (BRBs) as its seismic resistive components. Concurrent utilization of these devices will develop an efficient energy dissipating mechanism which is able to mitigate lateral displacements as well as the base shear, simultaneously. However, under certain circumstances which the presence of FVDs might not be essential, the proposed configuration has the potential to incorporate double BRBs in order to achieve the redundancy of alternative load bearing paths. This study is extending the modern Direct Displacement Based Design (DDBD) procedure as the design methodology for HPR-TGF systems. Based on a series of nonlinear time history analysis, it is demonstrated that the design outcomes are almost identical to the pre-assumed design criteria. This implies that the ultimate characteristics of HPR-TGFs such as lateral stiffness and inter-story drifts are well-proportioned through the proposed design procedure.

Seismic analysis of RC tubular columns in air-cooled supporting structure of TPP

  • Wang, Bo;Yang, Ke;Dai, Huijuan;Bai, Guoliang;Qin, Chaogang
    • Earthquakes and Structures
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    • v.18 no.5
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    • pp.581-598
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    • 2020
  • This paper aims to investigate the seismic behavior and influence parameters of the large-scaled thin-walled reinforced concrete (RC) tubular columns in air-cooled supporting structures of thermal power plants (TPPs). Cyclic loading tests and finite element analysis were performed on 1/8-scaled specimens considering the influence of wall diameter ratio, axial compression ratio, longitudinal reinforcement ratio, stirrup reinforcement ratio and adding steel diagonal braces (SDBs). The research results showed that the cracks mainly occurred on the lower half part of RC tubular columns during the cyclic loading test; the specimen with the minimum wall diameter ratio presented the earlier cracking and had the most cracks; the failure mode of RC tubular columns was large bias compression failure; increasing the axial compression ratio could increase the lateral bearing capacity and energy dissipation capacity, but also weaken the ductility and aggravate the lateral stiffness deterioration; increasing the longitudinal reinforcement ratio could efficiently enhance the seismic behavior; increasing the stirrup reinforcement ratio was favorable to the ductility; RC tubular columns with SDBs had a much higher bearing capacity and lateral stiffness than those without SDBs, and with the decrease of the angle between columns and SDBs, both bearing capacity and lateral stiffness increased significantly.

Vibration Test of a Full-Scale Five-Story Structure with Viscoelastic Dampers: Damper Design and Test for Response (점탄성 감쇠기가 설치된 실물크기 5층 건물의 진동실험: 감쇠기의 설계 및 응답실험)

  • 민경원;이상현;김진구;이영철;이승준;김두훈
    • Journal of the Earthquake Engineering Society of Korea
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    • v.7 no.3
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    • pp.9-15
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    • 2003
  • This paper presents a design procedure for viscoelastic dampers to be installed in a full-scale steel structure and observes their vibration control effect, based on the excitation method and the dynamic characteristics of the structure investigated in the companion paper, Additional damping ratios required to reduce the maximum displacement to a given level were obtained by convex model. The size of dampers was determined by observing the change in modal damping ratio due to the change in damper stiffness using the modal strain energy method, The effect of the supporting braces was also considered in the determination of the modal properties. Two viscoelastic dampers were installed at the first and second inter-stories, respectively and their response reduction is verified.

The effect of the temperature of rinsing water after brushing on oral malodor (잇솔질 후 양칫물 온도가 구취에 미치는 영향)

  • Chol, Woo-Yang;Kim, Hyun-Sook
    • Journal of Korean society of Dental Hygiene
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    • v.12 no.3
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    • pp.465-470
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    • 2012
  • Objectives : In general, the active of volatile compounds which become usually known as the principal ingredient of bad breath is closely connected with temperature. In this study, an investigation was made into the correlation between oral malodor and the temperature of rinsing water. Specifically, an analysis was made of saliva in rinsing water with relation to amount, flow and pH. In addition, a calculation was made of O'Leary index. The results are expected to be basic data for oral malodor reduction plans. Methods : A total of 30 women who are in their 20s without any systemic disease and teeth braces and non-pregnant were chosen for the study. The research was carried during 3 weeks from 28 Mar to 11 Apr in 2011. Results : Saliva was not significantly affected by the temperature of rinsing water, in connection with saliva amount, saliva flow and saliva pH. The O'Leary index and oral malodor was the highest in warm water, but the subjects preferred rinsing with cold water. Conclusions : In conclusion, oral malodor was found to be reduced in inverse proportion to the temperature of rinsing water. Thus, it is recommended to rinsing water with warm water after tooth brushing.

Development of a self-centering tension-only brace for seismic protection of frame structures

  • Chi, Pei;Guo, Tong;Peng, Yang;Cao, Dafu;Dong, Jun
    • Steel and Composite Structures
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    • v.26 no.5
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    • pp.573-582
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    • 2018
  • This study develops and numerically verifies an innovative seismically resilient bracing system. The proposed self-centering tension-only brace (SC-TOB) is composed of a tensioning system to provide a self-centering response, a frictional device for energy dissipation, and a high-strength steel cable as a bracing element. It is considered to be an improvement over the traditional self-centering braces in terms of lightness, high bearing capacity, load relief, and double-elongation capacity. In this paper, the mechanics of the system are first described. Governing equations deduced from the developed analytical model to predict the behavior of the system are then provided. The results from a finite element validation confirm that the SC-TOB performs as analytically predicted. Key parameters including the activation displacement and load, the self-centering parameter, and equivalent viscous damping are investigated, and their influences on the system behavior are discussed. Finally, a design procedure considering controlled softening behavior is developed and illustrated through a design example.

Cap truss and steel strut to resist progressive collapse in RC frame structures

  • Zahrai, Seyed Mehdi;Ezoddin, Alireza
    • Steel and Composite Structures
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    • v.26 no.5
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    • pp.635-647
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    • 2018
  • In order to improve the efficiency of the Reinforced Concrete, RC, structures against progressive collapse, this paper proposes a procedure using alternate path and specific local resistance method to resist progressive collapse in intermediate RC frame structures. Cap truss consists of multiple trusses above a suddenly removed structural element to restrain excessive collapse and provide an alternate path. Steel strut is used as a brace to resist compressive axial forces. It is similar to knee braces in the geometry, responsible for enhancing ductility and preventing shear force localization around the column. In this paper, column removals in the critical position at the first story of two 5 and 10-story regular buildings strengthened using steel strut or cap truss are studied. Based on nonlinear dynamic analysis results, steel strut can only decrease vertical displacement due to sudden removal of the column at the first story about 23%. Cap truss can reduce the average vertical displacement and column axial force transferred to adjacent columns for the studied buildings about 56% and 61%, respectively due to sudden removal of the column. In other words, using cap truss, the axial force in the removed column transfers through an alternate path to adjacent columns to prevent local or general failure or to delay the progressive collapse occurrence.

Cyclic testing of innovative two-level control system: Knee brace & vertical link in series in chevron braced steel frames

  • Rousta, Ali Mohammad;Zahrai, Seyed Mehdi
    • Structural Engineering and Mechanics
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    • v.64 no.3
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    • pp.301-310
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    • 2017
  • For further development of passive control systems to dissipate larger seismic energy and prevent the structures from earthquake losses, this paper proposes an innovative two-level control system to improve behavior of chevron braced steel frames. Combining two Knee Braces, KB, and a Vertical Link Beam, VLB, in a chevron braced frame, this system can reliably sustain main shock and aftershocks in steel structures. The performance of this two-level system is examined through a finite element analysis and quasi-static cyclic loading test. The cyclic performances of VLB and KBs alone in chevron braced frames are compared with that of the presented two-level control system. The results show appropriate performance of the proposed system in terms of ductility and energy dissipation in two different excitation levels. The maximum load capacity of the presented system is about 30% and 17% higher than those of the chevron braced frames with KB and VLB alone, respectively. In addition, the maximum energy dissipation of the proposed system is about 78% and 150% higher than those of chevron braced frames with VLB and KB respectively under two separate levels of lateral forces caused by different probable seismic excitations. Finally, high performance under different earthquake levels with competitive cost and quick installation work for the control system can be found as main advantages of the presented system.

Evaluation of seismic strengthening techniques for non-ductile soft-story RC frame

  • Karki, Prajwol;Oinam, Romanbabu M.;Sahoo, Dipti Ranjan
    • Advances in concrete construction
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    • v.9 no.4
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    • pp.423-435
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    • 2020
  • Open ground story (OGS) reinforced concrete (RC) buildings are vulnerable to the complete collapse or severe damages under seismic actions. This study investigates the effectiveness of four different strengthening techniques representing the local and global modifications to improve the seismic performance of a non-ductile RC OGS frame. Steel caging and concrete jacketing methods of column strengthening are considered as the local modification techniques, whereas steel bracing and RC shear wall systems are selected as the global strengthening techniques in this study. Performance-based plastic design (PBPD) approach relying on energy-balance concept has been adopted to determine the required design force demand on the strengthening elements. Nonlinear static and dynamic analyses are carried out on the numerical models of study frames to assess the effectiveness of selected strengthening techniques in improving the seismic performance of OGS frame.. Strengthening techniques based on steel braces and RC shear wall significantly reduced the peak interstory drift response of the OGS frame. However, the peak floor acceleration of these strengthened frames is amplified by more than 2.5 times as compared to that of unstrengthened frame. Steel caging technique of column strengthening resulted in a reasonable reduction in the peak interstory drift response without substantial amplification in peak floor acceleration of the OSG frame.