• Title/Summary/Keyword: post-tension

Search Result 287, Processing Time 0.025 seconds

Evaluation of Flexural Strength of Wide Sleepers with Reinforcing Bars for Quick-Hardened Concrete Track (보강철근이 적용된 급속경화궤도용 광폭침목의 보유 휨 내력 평가)

  • Bae, Young-Hoon;Lee, Il-Wha
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.19 no.2
    • /
    • pp.702-709
    • /
    • 2018
  • A quick-hardened concrete track was developed to improve the aged ballasted track to a concrete track, and applied to earthworks and tunnels of main and urban railways. Rebars for reinforcement are not generally applied to prestressed concrete sleepers. On the other hand, many cracked sleepers have been observed in railroad sites. A wide sleeper, which is one of the main components of quick-hardened concrete track, should be structurally safe and crack-resistant in a ballasted and concrete track to avoid this problem. In particular, a wide sleeper manufactured by a post-tension method must have reinforcing bars applied to the rail-seat section. In this paper, static tests, dynamic tests, and fatigue tests were carried out to compare the flexural strength and crack resistance performance of a wide sleeper with and without reinforcing bars for a quick-hardened concrete track. As a result of the test, if some reinforcing bars are applied appropriately to the rail-seat section of a wide sleeper, it will be possible to prevent the occurrence of cracks, delay the expansion of the crack width, and the flexural fracture.

Microanatomy of Philtral ridge (인중의 미세해부학적 고찰)

  • Lee, Jong-Ho;Jeon, Se-Il;Myung, Hoon;Lim, Koo-Young;Seo, Byung-Moo;Choi, Jin-Young;Choung, Pill-Hoon;Kim, Myung-Jin;Hong, Sam-Pyo;Lee, Jae-Il;Lim, Chang-Yun
    • Korean Journal of Cleft Lip And Palate
    • /
    • v.3 no.1
    • /
    • pp.11-16
    • /
    • 2000
  • Many efforts are made to achieve satisfactory cosmetic and functional result in the repair of cleft lip. However, repair may be complicated in many cases by distortion of the vermilion border, obliteration of the normal contour of the philtrum, and eclabium in spite of many methods used in these days. To achieve better results in cleft lip repair, thorough understandings of the relationship between the surface morphology of the upper and lower lip and the underlying musculature is necessary but reports about this topic is rare. So, our studies were performed on the full-thickness upper lips containing both philtral ridge up to columelar base and lower lip, 4 post-mortem specimens of 2 females and 2 males aged from 16 to 42, using serial histological sections taken in the transverse and vertical planes under light microscopy. Thorough understanding of the anatomical relationships is established and on the basis of our findings, we can postulate some criteria to create a normal and natural philtrum in a patient with a cleft lip, it would be necessary to restore the normal deep muscle attachments and superficial dermal attachments of the orbicularis muscle, to close the lip without tension, to restore thickness of the philtral ridge, and to minimise nonelastic scar tissue.

  • PDF

Multiscale modeling of reinforced/prestressed concrete thin-walled structures

  • Laskar, Arghadeep;Zhong, Jianxia;Mo, Y.L.;Hsu, Thomas T.C.
    • Interaction and multiscale mechanics
    • /
    • v.2 no.1
    • /
    • pp.69-89
    • /
    • 2009
  • Reinforced and prestressed concrete (RC and PC) thin walls are crucial to the safety and serviceability of structures subjected to shear. The shear strengths of elements in walls depend strongly on the softening of concrete struts in the principal compression direction due to the principal tension in the perpendicular direction. The past three decades have seen a rapid development of knowledge in shear of reinforced concrete structures. Various rational models have been proposed that are based on the smeared-crack concept and can satisfy Navier's three principles of mechanics of materials (i.e., stress equilibrium, strain compatibility and constitutive laws). The Cyclic Softened Membrane Model (CSMM) is one such rational model developed at the University of Houston, which is being efficiently used to predict the behavior of RC/PC structures critical in shear. CSMM for RC has already been implemented into finite element framework of OpenSees (Fenves 2005) to come up with a finite element program called Simulation of Reinforced Concrete Structures (SRCS) (Zhong 2005, Mo et al. 2008). CSMM for PC is being currently implemented into SRCS to make the program applicable to reinforced as well as prestressed concrete. The generalized program is called Simulation of Concrete Structures (SCS). In this paper, the CSMM for RC/PC in material scale is first introduced. Basically, the constitutive relationships of the materials, including uniaxial constitutive relationship of concrete, uniaxial constitutive relationships of reinforcements embedded in concrete and constitutive relationship of concrete in shear, are determined by testing RC/PC full-scale panels in a Universal Panel Tester available at the University of Houston. The formulation in element scale is then derived, including equilibrium and compatibility equations, relationship between biaxial strains and uniaxial strains, material stiffness matrix and RC plane stress element. Finally the formulated results with RC/PC plane stress elements are implemented in structure scale into a finite element program based on the framework of OpenSees to predict the structural behavior of RC/PC thin-walled structures subjected to earthquake-type loading. The accuracy of the multiscale modeling technique is validated by comparing the simulated responses of RC shear walls subjected to reversed cyclic loading and shake table excitations with test data. The response of a post tensioned precast column under reversed cyclic loads has also been simulated to check the accuracy of SCS which is currently under development. This multiscale modeling technique greatly improves the simulation capability of RC thin-walled structures available to researchers and engineers.

Development and Field Application of Portable Tensioning System Using Segmental CFT Member (분절형 CFT부재를 이용한 이동식 프리텐션 제작대의 개발 및 활용)

  • Lee, Doo Sung;Kim, Tae Kyun;Lee, Sung Chul
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.34 no.3
    • /
    • pp.965-975
    • /
    • 2014
  • Pretension PSC (Prestressed Concrete) members are subjected to a certain limit of size as they are generally produced in the off-site plant and transferred to the site due to the large scale of the product on system. In this study, a portable pretensioning production system has been developed, which allow us to apply the pretension method on site. Considering that a 50m span PSC girder using the pretension method requires a pressing device to endure a large jacking force, the portable pretension production system has to ensure safety against such a large pretension jacking force. In this study, the portable pretensioning system to produce a 50m span pretension girder was manufactured by using CFT (Concrete Filled steel Tube) members. In order to understand the stability of the system and the behavior of the elements, a static loading test was conducted and the stability of the proposed portable pretensioning production system was confirmed. The developed portable pretension system was applied to several construction sites and was investigated the problems on site. During the pretension girder and slab members that was producted by this pretension system in construction site, it has be found the several advantages such as simple fabrication processes, reduction of prestress-loss, and a decrease of 15% compared with the fabrcation cost of post-tension girder. After due consideration of the problems, this portable pretension system will be improved.

Medico-Legal Consideration of Hemopneumothorax - Closing Claim Study- (${\cdot}$기흉과 관련된 의료법학적 문제에 대한 고찰 -종결된 사건을 중심으로-)

  • Bae, Hyu-Na;Cheon, Young-Jin
    • Journal of Chest Surgery
    • /
    • v.39 no.2 s.259
    • /
    • pp.117-126
    • /
    • 2006
  • Background: The purpose of this study is to describe the characteristics of malpractice claims related to hemopneumothorax and to identify the causes and potential preventability of such claims. Material and Method: A retrospective study was performed by reviewing the records in the Lawnb website and Lx CD-rom: the records on closed malpractice claims involving hemopneumothorax were abstracted from the files available for analysis. The records were reviewed and were analysed to determine the etiology of hemopneumothorax, patient age, results of lawsuit and indemnity payment, underlying diseases, cause of death or complications, and the factors associated with a successful defense. Result: Seven closed claim involving hemopneumothorax were founded in the data for malpractice. Three claims were supreme court decision, one was a high court decision and three claims were district court decision. The most common cause of death was tension pneumothorax. Four of which resulted in indemnity payments. Conclusion: While malpractice claims involving hemopneumothorax were uncommon, they resulted in a high rate and amount of indemnity payments. Claims are more common in pediatric patients. In case of iatrogenic hemopneumothorax, post-procedural X-ray can improve patient outcome and is also associated with decreased indemnity risks. Informed consent is also important.

Recognition of Complication of Superficial Brachial Axial Pattern Flap in a Dog (표층상완축상피판이식술과 전층망상식피술의 적용 예)

  • Kim, Se-Hoon;Heo, Su-Young;Cho, Young-Kwon;Lee, Hae-Beom;Lee, Ki-Chang;Kim, Min-Su;Kim, Nam-Soo
    • Journal of Veterinary Clinics
    • /
    • v.26 no.6
    • /
    • pp.637-640
    • /
    • 2009
  • A 13-year-old female 30 kg Korean Jin-do dog was presented with severe defects due to vasculitis and perivascular dermatitis at the left antebrachium area. A left superficial brachial axial pattern flap was elevated to cover the defect and the wound was covered. However, one week post surgery, the flap was survived about 1/3 of total flap length. Remaining two thirds defects were performed by the free skin mesh graft as an additional method. After ten days, the entire wound was achieved completely. Skin flaps carry own blood supply in other hands, the flap method is dependent upon continuation of adequate circulation until vascularization takes place. Because they are much thicker than other grafts, this is a slower process and the flap method is vulnerable to problems with kinking or tension of the base. According to this case, a practician has to consider length of flap and thickness in order to vascular perfusion when superficial brachial axial pattern flap is performed in a dog.

The Effects of Cranio-Sacral Therapy on Brain Function Quotient of Elderly with Long-term Care Insurance Service (두개천골요법이 장기요양시설노인의 뇌기능지수에 미치는 효과)

  • Lee, Jung-eun
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.17 no.1
    • /
    • pp.474-484
    • /
    • 2016
  • This study was performed to identify the effects of the improvement of brain function by CST on the elderly with the 2nd or 3rd grade of long-term care insurance service. A quasi-experimental design using a nonequivalent control group, pre-post test was used. A total of 12 elders (6 in the experimental group and 6 in the control group) were recruited. Upledger CST(10-Step Protocol) was performed on each subject for 50 minutes per session, once a week, for a total of 8 treatments over an 8 week period from Jan to Feb 2015. The brain function quotient was measured before the 1st CST and after the last CST by portable EEG measurement device using a 2 Channel neuro-feedback system. The data was analyzed by SPSS (Ver. 18.0) program. After CST intervention, the attention quotient (AQ), level of tension, anti-stress quotient (ASQ), emotion quotient (EQ) and brain quotient (BQ) of the experimental group was significantly better than that of the control group. These results showed that the CST was effective in reducing the level of fatigue by the AQ, increasing the physical and psychological stress relief by the ASQ, emotional balance by the EQ, and improving the total brain function by the BQ. Therefore, CST can be used as an effective intervention for improving the health and brain function of the elderly in health facilities.

Assessment of the Application Status of Transcutaneous/Percutaneous Vagus Nerve Stimulation for Musculoskeletal Pain: A Scoping Review for Utilization in Korean Medicine and Subsequent Research (경피적 미주 신경 자극술의 근골격계 통증에 대한 적용 현황 파악: 한의학적 활용 및 후속 연구를 위한 Scoping Review)

  • Gun Hee Bae;Jeong Hoon Ahn;Dong Jin Jang;Jeong Hee Noh;Jae Kwon Shin;Eun Seok Jin;Sun Kyu Yeom;Seung Ju Oh
    • Journal of Korean Medicine Rehabilitation
    • /
    • v.34 no.1
    • /
    • pp.65-81
    • /
    • 2024
  • Objectives This study aimed to understand the general research trends, applicated disease, and methodology of transcutaneous/percutaneous vagus nerve stimulation, contemplating its clinical use in traditional Korean medicine and future research directions. Methods A scoping review was conducted following Arksey and O'Malley Framework Stage and adhering to the PRISMA extension for scoping reviews: checklist and explanation. Papers published until October 30, 2023, were investigated across 10 databases (PubMed, Embase, Scopus, Web of Science, China National Knowledge Infrastructure, Oriental Medicine Advanced Searching Integrated System, Korean Studies Information Service System, KMbase, Science ON, Research Information Sharing Service. The search terms used were 'Transcutaneous/Percutaneous vagus nerve stimulation'. Results Since 2021, the application of transcutaneous/percutaneous vagus nerve stimulation for musculoskeletal symptoms has been actively researched, predominantly in Asia (37%), Europe (37%), and North America (21%). All 19 papers were part of clinical studies. Chronic pain was noted that most applied disease, it also was found to potentially aid in acute post-surgical pain relief. Major assessment tools include not only simple pain metrics but also pain perception, vagal nerve tension, quality of life, and inflammatory markers. Most procedures were carried out through the ear, which offers a favorable site for therapeutic stimulation without notable side effects. And parameter analysis, frequencies typically ranged around 25 Hz to 30 Hz, while pulse widths were commonly set at 250 ㎲ or 300 ㎲. Conclusions Transcutaneous/percutaneous vagus nerve stimulation is easily accessible through acupuncture in Korean medicine. Therefore, if future studies establish parameters and clinical significance, it could be utilized as a therapeutic modality.

A Study on Sexual Function of Women with Coronary Artery Disease (관상동맥질환 여성의 성기능에 관한 연구)

  • Kim, Choon Shim;So, Hyang Sook
    • Korean Journal of Adult Nursing
    • /
    • v.12 no.1
    • /
    • pp.99-111
    • /
    • 2000
  • The purpose of this study was to identify risk factors related to sexual function of women with coronary artery disease, and to determine the predictors of sexual function. The study design, a descriptive correlational study, was done through structural questionnaire and interview. A total of 50 subjects from C University Hospital at Kwang-ju city who have undergone coronary angiography at department of cardiology were observed and interviewed from Feb. 22, 1999 to March. 23, 1999. The number of affected vessels, the level of total serum cholesterol, and the ejection fraction of 2-D echo cardiography were analyzed to evaluate the severity of coronary artery disease. And also type A behavior pattern, health behavior, Brief Index of Sexual Functioning for Women (BISF-W) were measured. The data obtained were analyzed using percentage, mean and standard deviation, t-test, ANOVA, Pearson's correlation coefficient, and stepwise multiple regression analysis via SPSS PC+. The results of this study were as follows: 1. The mean age of the subjects were 58.1 and 72.0% of those have been married over 30 years. Seventy two percentage were unemployed and monthly family income of 56.6% was less than 1,000,000 won (approximately $ 840). Eighty percent were in their postmenopausal state, and the frequency of sexual intercourse of 84.0% were two to three times per month. 2. The scores of type A behavior pattern were from 16 to 38(mean 24.94) and health behavior ranged from 21 to 43(mean 31.2). Abstinence from smoking, alcohol, and caffeine were best compliant factors and weight control and exercise were least abided ones. The result of 2D-ECHO EF showed that the half of the subjects were abnormal, and 24% had more than 240mg/dl of total serum cholesterol. The coronary angiography showed that 64% of the subjects had more than one affected vessels. 3. The predictors to explain the factor score of 'orgasm' were number of health examination, the pre- or post-menopausal state, protestant, number of coronary vessel affected, level of serum total cholesterol, and comorbid group of hypertension and diabetes, and it's total variance accounted for 52.4%. The predictors to explain the factor score of 'sexual activity' were comorbid group of hypertension and diabetes and type A behavior pattern, which accounted for 22.4% of total variance. The predictors to explain the factor score of 'sexual satisfaction' were type A behavior pattern, no religion, exercise, level of serum total cholesterol, and pre or post menopausal state, which accounted for 52.1%. The predictors to explain the factor score of 'sexual desire' were the period of marriage, type A behavior, employment or unemployment, and weight control, which accounted for 43.2%. The predictors to explain the factor score of 'external force of sexual functioning' were physical overload and exercise, which accounted for 41.1%. The predictors to explain the factor score of 'sexual activity' were family monthly income, catholics, and exercise, and which accounted for 35.4%. Above results lead us to some consensus that sexual function of women with coronary artery disease is related to various factors including vasogenic factors such as total serum cholesterol level, number of coronary vessel affected, an endocrinal factor such as menopausal state, and type A behavior pattern as a sociopshychological factor. And also health behaviors such as fitness care, overwork, weight control, and emotional tension are contributed to sexual function.

  • PDF

ACL reconstruction with autologous hamstring tendon - Short term clinical result using new femoral suspensory fixation device 'Cross Pin' and graft tensioner for maintaining a constant tension- (자가 슬괵건을 이용한 전방 십자 인대 재건술 - 새로운 대퇴부 현수고정법인 Cross Pin과 일정한 긴장력 유지를 위한 Graft Tensioner 사용의 단기 추시 결과 -)

  • Seo, Seung-Suk;Kim, Chang-Wan;Kim, Jin-Seok;Choi, Sang-Yeong
    • Journal of Korean Orthopaedic Sports Medicine
    • /
    • v.10 no.1
    • /
    • pp.27-34
    • /
    • 2011
  • Purpose: To evaluate the short term clinical result of ACL reconstruction with autologous hamstring tendon using Cross pin and Graft Tensioner and to seek way to resolve the experienced technical problems. Materials and Methods: From January 2008 to March 2009, 35 patients who had been treated arthroscopic ACL reconstruction were enrolled. The femoral side of ACL graft was fixed with Cross pin. The tibial side of graft was fixed with Intrafix and post-tie. The graft was tensioned with Graft Tensioner at 80N. We analyzed the clinical, radiographic results and complications. Results: IKDC subjective score and Lysholm score improved to 89.1 and 91.4 points. Also, Pivot shift test and One-leg hop test showed good results postoperatively. Side to side difference using KT-1000 arthrometer and Telos stress radiography improved compared with normal limb to $2.8{\pm}1.6$ mm and $2.6{\pm}1.3$ mm, respectively. The femoral tunnel enlarged to $2.3{\pm}1.1$ mm. Soft tissue irritation and femoral tunnel-graft harness length mismatch, femoral tunnel-cross pin tunnel mismatch were happened as peri-operative complications. Conclusion: Using of Cross pin and Graft Tensioner for ACL reconstruction with hamstring tendon is one of the good method for obtaining stability in short-term clinical result. But to reduce femoral tunnel-cross pin mismatch, it needs to shorten femoral bone tunnel and to create cross pin tunnel as vertical as possible. And to reduce femoral tunnel-graft harness mismatch, it needs to advance position rod further 3 mm when to create femoral tunnel.

  • PDF