• Title/Summary/Keyword: Maintenance effects

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Axial Compressive Behavior of the R/C Short Columns Strengthened with CFS (탄소섬유쉬트로 횡보강된 R/C단주의 압축거동)

  • Shin, Sung-Woo;Bahn, Byong-Youl;Lee, Kwang-Soo;Ahn, Jong-Moon;Hwang, Jun-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.2 no.4
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    • pp.201-208
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    • 1998
  • To observe the confinement effects of Carbon Fiber Sheet(CFS) on the high-strength R/C short columns, Fifteen specimens with CFS were manufactured and tested under uni-axial compressive load. Major variables of this study are amount, spacing, type of CFS and amount of transverse steel. Increasing the amount of transverse steel and CFS, compressive strength and axial rigidity is improved. R/C columns with transverse steel and CFS exhibited less axial stress than columns with only CFS. From the test results, it is shown that the area confined with transverse steel and CFS is considerably important to evaluate axial stress of R/C short columns.

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A Rational Approach to the Flexural Concrete Beam Analysis with Crack Growth using Fracture Mechanic Concepts (크랙을 고려한 휨을 받는 콘크리트보의 해석)

  • Heo, Gwang Hee;Choi, Man Young
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.2 no.4
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    • pp.159-171
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    • 1998
  • This study attempts to develop a rational approach to flexural concrete beam analysis with crack growth. In order to develope analytical solutions, several simplification and assumption are made and the Hillerborg fictitious crack model is adapted for new rational approach to the flexural concrete beam. To provide desired results, the concrete beams with various conditions(more than 126 beam conditions) are analyzed. Before producing the results, these assumptions are founded to be justified by comparison with a FE analysis. The results for each condition of the beams are presented in terms of crack lengths, the strength and cracking stability of concrete beams. And also size effects in a flexural concrete beam is studied using a new flexural cracking model.

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Shear Capacity of Reinforced Concrete Haunched Beams by Shear Span-to-Depth Ratio and Haunch Slope (경간비와 헌치 기울기 변화에 따른 철근콘크리트 헌치보의 전단성능에 관한 연구)

  • Song, Ho-San
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.6 no.1
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    • pp.119-129
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    • 2002
  • Reinforced concrete haunched beams have been used for enhancement of shear resistance of beams to avoid the stress concentration. But American and British codes do not give my formula for the design of haunched beams. The purpose of this research is to experimentally investigate the shear failure of reinforced concrete punched beams for various haunch inclinations and shear span-to-depth ratios. The experimental results showed that even though shear behavior of haunched beam were similar to that of resembled rectangular beams, shear span-to-depth ratios and inclinations of haunch had effects on shear cracking strength.

Behavior Characteristics of Reinforced Concrete Beam Strengthened with Carbon Fiber Reinforced Polymer Plate (CFRP로 보강된 철근콘크리트 보의 거동 특성)

  • Park, Jung-Yeol;Hwang, Seon-Il;Cho, Hong-Dong;Han, Sang-Hoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.3
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    • pp.125-131
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    • 2003
  • This paper presents the characteristics of flexural behavior of RC beam strengthened with CFRP(Carbon Fiber Reinforced Polymer Plate). Experimental variables included the strengthening length, width, reinforcement ratio, end anchorage and preloading corresponding to 75 percent of ultimate capacity and the effects according to each experimental variables were analyzed. To study, a total 21 RC beams were constructed, tested and the response of the beams in terms of ultimate load, deflection, strain of CFRP, failure mode were examined.

SAR of COX-2 Inhibitors (COX-2 억제제의 구조-활성)

  • 권순경
    • Biomolecules & Therapeutics
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    • v.9 no.2
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    • pp.69-78
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    • 2001
  • Cyclooxygenase (COX) is an enzyme, which catalyzes the production of prostaglandins from arachi-donic acid and exists in two isoforms (COX-1 and COX-2). COX-1 is involved in the maintenance of physiological functions such as platelet aggregation, cytoprotection in the stomach and maintenance of normal kidney function. COX-2 is induced significantly in vivo under inflammatory conditions. COX-1 and COX-2 serve different physiological and pathological functions. All commercially available nonsteroidal antiinflammatory drugs (NSAIDS) are inhibitors of both COX-1 and COX-2. Therefore, selective inhibitors of COX-2 may be effective antiinflammatory agents without the ulcerogenic effects associated with current NSAms. Since the mid 1990s, a number of reports have been appeared on the preparation and biological activity of selective COX-2 inhibitors. Recently celecoxib, and rofecoxib, the representative COX-2 inhibitors, are introduced in the drug market. In this paper the relationship of structure-activity for selective COX-2 inhibitors is reviewed.

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Seismic Performance of Precast Concrete Large Panel Structures Subjected to Horizontal Cyclic Loading (반복 횡하중을 받는 프리캐스트 대형 판구조의 내진성능에 관한 연구)

  • Seo, Soo-Yeon;Lee, Li-Hyung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.3 no.3
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    • pp.261-268
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    • 1999
  • The seismic performance of precast concrete panel structures tested previously has been evaluated in this paper. Hysteretic curves of test specimens are idealized to elasto-plastic curves to get reliable yielding and ultimate displacements. For the idealized curves, ductility and energy dissipation capacity of specimens have been evaluated using a few guide lines. In addition, the strength capacity of specimens is checked for the strength demand caused by the design earthquake load including overturning moment effects. The result shows while the strength of specimen with joint box for vertical continuity is little bit lower than that of specimen connected by welding, the ductility of the former is higher than that of the latter. The energy dissipation ratios of PC specimens are ranged from 83% to 96% of that of Re specimen and the average of those are shown 90%.

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A Study on Stability of Middle Slabs supporting Train Loads in Subway Station (열차하중을 지지하는 지하철정거장 중간슬래브의 안정성 연구)

  • Woo, Jong-Tae;Yhim, Sung-Soon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.3 no.3
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    • pp.195-202
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    • 1999
  • This study present the stability of middle slabs directly supporting train loads in the subway station. According to results of Quality confirmation, mixing and curing conditions are good. But, when effects of hydration heat are analyzed, cracks seems to take place because tensile stress is higher than tensile strength in several points of middle slabs. It is found that vibration by train running don't have an effect on cracks in the structure. The structural analysis shows that there is no problem on the stability of structural body, but the design through 3-dimensional analysis is need to consider columns and opening specially in the subway station structures.

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Optimal Implementation Strategies of Building Information Modeling for Construction Projects of LH

  • Lee, Ji-Eun
    • International conference on construction engineering and project management
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    • 2015.10a
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    • pp.60-62
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    • 2015
  • The BIM-based architectural design can be the optimal method to improve all sectors of construction industry and reduce environmental impact through digital technologies. The goals and effects of BIM needs in LH to be newly planned based on the experience of public sectors, which will ultimately contribute to maximization of effectiveness. Referring the excellent case in the UK, the current BIM standards according to maturity level 2 handle the contents related to modeling, collaborative data production, data management and assure BIM data have to be used from building construction to operation and maintenance of buildings. Therefore the strategy for the utilization of BIM for construction projects in LH consisted of three steps; first, the minimization of defects via BIM: second, strengthening the competitiveness of construction and asset management: third, upgrading the system of building production and maintenance control. After this trial, LH can accumulate know-how for building construction to be more costeffective and competitive.

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Computer Vision-based Structural Health Monitoring: A Review

  • Jun Su Park;Joohyun An;Hyo Seon Park
    • International Journal of High-Rise Buildings
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    • v.12 no.4
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    • pp.321-333
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    • 2023
  • Structural health monitoring is a technology or research field that extends the service life of structures and contributes to the prevention of disaster accidents by continuously evaluating the safety, stability, and serviceability of structures as well as allowing timely and proper maintenance. However, the contact-type sensors used for it require considerable time, cost, and labor for installation and maintenance. As an alternative, computer vision has attracted attention recently. Computer vision has the potential to make quality, deformation, and damage monitoring for structures contactless and automated. In this study, research cases in which computer vision was utilized for structural health monitoring are introduced, and its effects and limitations are summarized. Therefore, the applicability and future research directions of computer vision-based structural health monitoring are discussed.

Risperidone as a Janus in Mood Disorder (기분장애에서 risperidone의 양면성)

  • Yoon, Doh Joon
    • Korean Journal of Biological Psychiatry
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    • v.4 no.2
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    • pp.198-210
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    • 1997
  • To examine the double-faced thymoleptic(antidepressant and antimanic) effects of risperidone in mood disorders, this article reviews the psychotropic-induced mania, thymoleptic effects of antipsychotics, therapeutic effects of risperidone and risperidone(RIS)-induced mania(RIM) in mood disorders, risk factors of RIM, possible neurochemical mechanism of these thymoleptic effects, pathophysiological and clinical significance of thymoleptic effects, and suggestive clinical guideline of RIS in mood disorders. RIS appeared effective for bipolar disorder at a lower dose than that recommended for schizophrenia, especially in the cases of maintenance of mood stabilizers, and gradual titration from low doses. Manic induction/exacerbation can occur by chance during RIS treatment in mood disorders, schizoaffective disorders, and schizophrenias. The possible risk factors for RIM are refractory mood disorder, especially in bipolar I disorder with poor initial response ; refractory schizoaffective disorders, especially in bipolar type with poor initial response ; refractory chronic schizophrenias, especially with initial responses ; psychotic features ; higher initial doses ; rapid titration ; combined therapy with antidepressants in refractory depression ; and RIS monotherapy in mania/hypomania. RIS is a drug that preferentially block 5-HT2 receptors. The effects of low dose are due mainly to the blockade of 5-HT2 receptors. There are more gradual increase in D2 blockade with increasing dose and this D2 blocking properties become apparent at higher doses. This may be related to a modulation of dopaminergic transmission by 5-HT2 antagonism at lower doses with the direct action of RIS on DA receptors coming into play at higher dose. The serotonergic antagonistic effect may be important for its effects on depressive symptoms. This, together with adequate blo-ckade of D2 receptors, may not necessarily lead to destabilization of mood disorder, but rather to more therapeutic effects. Therefore, this dose-receptor affinity relationship with both antidepressant and antimanic effects according to treatment duration can explain a continuum of antidepressant effect, antimanic effect, behavioral stimulation, and manic/hypomanic induction/exacerbation. It was the recognition of a useful psychiatric side effects by a thoughtful observer with fertile minds that led to their ultimate utilization as psychotropic drugs, i.e., phenothiazine, MAOI, TCA, and lithium. And, in vivo pharmacological challenge by novel psychotropics, as a neurochemical probe, with more specific actions is a useful tool to select pharmacologically homogeneous subgroup of the same phenotypical(clinical) condition, to further study the unknown underlying pathogenesis of various mental illnesses. Finally, RIS may be a useful alternative or adjunctive drug for patients with mood disorders without psychotic features or refractory to treatment with standard antipsychotic drugs. The more conservative doses(tirated slowly from 1-3 mg/d) of RIS, and maintenance of mood stabilizer in the cases with risk factors of RIM are recommended in mood disorder.

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