• Title/Summary/Keyword: reinforcing effect

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Effect of Volume Fraction of Fibers on the Mechanical Properties of a Lightweight Aggregate Concrete Reinforced with Polypropylene Fibers (섬유 혼입률에 따른 섬유보강 경량골재 콘크리트의 역학적 특성)

  • Lee, Haeng-Ki;Song, Su-Yong
    • Journal of the Korea Concrete Institute
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    • v.18 no.6 s.96
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    • pp.743-748
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    • 2006
  • This paper presents results of an experimental study conducted to investigate the effect of volume fraction of fibers on the mechanical properties of a fiber-reinforced, lightweight aggregate concrete(FRLAC) that was produced without an autoclave process. The FRLAC enhanced the strength of lightweight, cellular concrete by adding polypropylene fibers and lightweight aggregates. To investigate the effect of volume fraction of fibers on the mechanical behavior of FRLAC and to determine the optimal volume fraction of fibers, a series of compression and flexural strength tests on FRLAC specimens with various fiber volume fractions(0%, 0.10%, 0.25%, 0.50%) were conducted. It was observed from the tests that a 0.25% volume fraction of fibers maximized the increase in the strength of FRLAC and the fibers controlled cracking in FRLAC.

Analysis of Geotextile Bag Reinforcing Effect on Railway Roadbed (지오텍스타일 백을 이용한 철도노반 보강효과 분석)

  • Lee, Dong-Hyun;Shin, Eun-Chul
    • Journal of the Korean Geosynthetics Society
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    • v.4 no.4
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    • pp.3-11
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    • 2005
  • In this study, a large-scale laboratory model test and 2-D numerical analysis were conducted to verify the reinforcement effect by utilizing geotextile bag on the railway roadbed. Static loading which simulated train load was applied on the geotextile-reinforced railway roadbed and also unreinforced railway roadbed. Computer program named Pentagon 2-D which is a part of FEM programs was used in the numerical analysis. Based on the results of laboratory test and 2-D numerical analysis, the effect of load distribution and settlement reduction was found to be depending on the geotextile characteristics, tensile strength of geotextile, and interface friction angle between geotextile bags. In general, the result of 2-D numerical analysis shows lower value than that of laboratory test.

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Synergistic Effect in Mechanical Properties of Sheet Molding Compound via Simultaneous Incorporation of Glass Fiber and Glass Bubble Fillers (유리섬유와 유리버블에 의한 Sheet Molding Compound 강도의 시너지 효과)

  • Noh, Ye Ji;Lee, Yong Cheol;Hwang, Taewon
    • Composites Research
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    • v.31 no.1
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    • pp.8-11
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    • 2018
  • Sheet molding compound (SMC) is one of the most economical fiber reinforced composite fabrication processing for automotive applications. In this study, we studied the optimum formulation for the production of SMC which shows low specific gravity without lowering the mechanical properties by using glass bubble (GB) which is a low specific gravity filler and glass fiber (GF) as a reinforcing material. The tensile strength increased with the increase of the GF in the SMC, and the specific gravity decreased with the increase of the GB. The synergistic effect of improving the mechanical properties as the specific gravity is lowered is found in the optimum formulation. The synergy effect was confirmed by the internal structure analysis that the dispersion effect of the crack propagation of the GB and the improvement of the binding force between the fiber and the matrix due to the incorporation of the GB.

The Effect of Brand Evidence on Positive Emotion, Negative Emotion, and Attitude in Restaurant Industry

  • KIM, Eun-Jung
    • The Korean Journal of Franchise Management
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    • v.12 no.1
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    • pp.45-55
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    • 2021
  • Purpose: How to build the positive emotion of customer is very important, because it affects the positive attitude. Brand evidence has a significant impact on consumer behavior in terms of reinforcing consumers' perception of food service companies and differentiating them from competing brands. Thus, this study examines the effect of brand evidence on emotion (positive emotion and negative emotion), and attitude in restaurant industry. Research design, data, and methodology: This study examines the structural relationship among brand evidence, emotion, and attitude. Brand evidence divide into three sub-dimensions such as physical evidence, core service, and employee service. In order to test the purposes of this study, research model and hypotheses were developed. The questionnaire items were modified and used according to the content of this study based on previous studies. All constructs were measured by multiple items tested and developed in the previous research. The data were collected from 439 restaurant users from Seoul area were analyzed using SPSS 22.0 and SmartPLS 3.0 program. A total of 460 questionnaires were distributed and a survey was conducted for 4 weeks, and a total of 439 were used for analysis, excluding non-response data and 21 unusable response data among the collected questionnaires. Frequency analysis was conducted to identify the general characteristics of the survey subjects. To measure the reliability and validity of the measurement tools, confirmatory factor analysis was conducted. Structural model analysis was conducted to verify the research model. Result: The findings demonstrate that physical evidence, core service, employee service had positive effects on positive emotion. And core service and employee service had negative effects on negative emotion while physical evidence did not have. Also, positive emotion had positive effect on attitude and negative emotion had negative effect on attitude. Conclusions: The findings of this study provide guidelines on how to enhance competitiveness in restaurant industry through understanding brand evidence's effects on raising perceived consumer's emotion and attitude. Therefore, food service companies should establish a marketing strategy that can stimulate positive emotions through brand evidence, which is all factors related to service brands that influence consumers' evaluation of service products and purchase decision-making process.

Seismic Retrofitting of Existing Reinforced Concrete Columns Using Binding Column Method (외부부착형 BCM공법으로 보강된 철근콘크리트 기둥의 내진보강)

  • Hur, Moo-Won;Park, Tae-Won;Lee, Sang-Hyun;Park, Hyun-Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.26 no.5
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    • pp.119-126
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    • 2022
  • This study proposed a BCM(Binding Column Method) that can reinforce the insufficient seismic force of piloti buildings that are not designed for seismic resistance. In addition, 4 reinforcement specimens and 1 reference specimen were manufactured for the proposed seismic reinforcement method. The effect of improving seismic performance before and after reinforcement was examined through repeated loading tests. As a result of experiment, seismic reinforcement specimen with BCM system showed hysteretic characteristics of a large ellipse with great energy dissipation ability and increased strength and stiffness, while reference specimen showed rapid reduction in strength and brittle shear failure column. In addition, it can be seen that the reinforcing effect is improved as the gap is narrow, the torque is large, and the thickness of the L-shaped steel sheet is thicker. The SC4 specimen showed the best seismic performance reinforcement effect.

Shear Capacity of the RC T Beams Strengthened for Shear with NSM FRP Strips (FRP 판으로 표면매립 전단보강된 철근콘크리트 T형 보의 전단성능)

  • Seo, Soo-Yeon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.26 no.6
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    • pp.256-262
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    • 2022
  • The purpose of this study is to define the shear reinforcing effect of Near-Surface-Mounted (NSM) FRP strips in reinforced concrete (RC) member through a test. Three T shaped RC beams were made and two of them were strengthened with NSM FRP strips for increase shear strength. And those were tested to find the shear strengthening effect. In the test, two case of shear strengthening methods were considered such as 1) with NSM FRP strips having full embedded length and 2) with NSM FRP strips having some what short embedded length and additional externally bonded FRP sheet. As a result, the shear strengthening effect could be obtained when the NSM FRP strips are embedded to have full length up to the bottom of slab. However the shear strength was not increased in the case of having somewhat short embedded length of NSM FRP strips even additional EB sheet was enhanced.

An Experimental Study about Behavior of a Repaired Underwater Structure with an Epoxy Fiber Panel and Polymer Mortar (에폭시 섬유판넬과 폴리머 모르타르로 단면보수된 수중구조물의 거동에 관한 실험적 연구)

  • Hong, Sung-Nam;Park, Jun-Myoung;You, Chung-Jun;Han, Kyoung-Bong;Park, Sun-Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.1 s.53
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    • pp.69-77
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    • 2009
  • An underwater structure is made to put with serious damage state by special environmental factors. If this damage phenomena persist, as for the structure, it is generated a structural serious problem because of the corrosion of a reinforcing bar and the loss of the concrete cut end. Repair work of an underwater structure is very harder than repair work in land, and it is actual that certification about a maintenance effect is uncertain. And the existing repair method is applied to a structure damaged with you without verification of a repair effect by a foreign reward and experience. In this study, a repair method about an underwater structure was proposed and observed a behavior characteristic and interface failure of an specimens. and comparison analyzed an effect of a proposed maintenance method.

Reinforcing effects of carbon fiber sheet by compressive strength differences on the RC slabs (도로교 RC 상판의 압축강도 차이에 따른 탄소섬유시트 보강효과)

  • Won, Chan Ho;Abe, Tadashi;Ahn, Tae-Ho
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.26 no.1
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    • pp.23-27
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    • 2016
  • This study investigates the effect of carbon fiber sheet (CFS) and carbon fiber strand sheet (CFSS) on the fatigue resistance and compressive strength of RC slabs. The results of a comparison of the number of equivalent cycles between the CFS- and CFSS-reinforced RC slab test specimens obtained from a fatigue test indicate that the CFSS-reinforced RC slab has 1.2~1.3 times greater effect of reinforcement than the CFS-reinforced RC slab. This study also indicates that the fatigue resistance of the CFS- and CFSS-reinforced RC slabs is ensured when the compressive strength of concrete is not lower than the specified design strength prescribed in the Specifications for Highway Bridges but is not ensured when the compressive strength of concrete is lower than the specified design strength, although the effect of reinforcement is secured.

Settlement Reduction Effect of the Geogrid Reinforced Stone Column System (고강도 지오그리드로 보강된 Stone Column 공법의 침하감소효과)

  • Park, Sis-Am;Cho, Sung-Han;Yoo, Chung-Sik;Lee, Dae-Young
    • Journal of the Korean Geosynthetics Society
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    • v.5 no.1
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    • pp.15-23
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    • 2006
  • Sand Compaction Pile and Stone Column method have been used in widely during several decades as a technique to reinforce soft soils and increasing ultimate bearing capacity, accelerate consolidation settlement of the foundation ground. Stone column method, making a compaction pile using crushed stone, is a soft ground improvement method. However, stone column method is difficult to apply to the ground which is not mobilized enough lateral confine pressure because no bulging failure resistance. Hence, in present study, development the geogrid reinforced stone column system for settlement reduction and wide range of application of stone columns. To develop this system, triaxial compression tests were conducted for evaluation which is about behavior characteristics of stone column on replacement rate and confine pressure. Then, 3-dimensional numerical analysis were evaluated for application of the GRSC (geogrid reinforced stone column) system as evaluate behavior characteristics and settlement reduction effect of stone column reinforced by geogrid on types and reinforcing depth change of geogrid.

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Effectiveness of Obesity management programs: systematic review and meta-analysis (메타분석을 이용한 비만관리 프로그램의 효과분석)

  • Lee, Hyo-Young
    • Korean Journal of Health Education and Promotion
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    • v.24 no.4
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    • pp.131-147
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    • 2007
  • As overweight and obese people have increased, obesity management programs have generated much concern in Korea. Many types of obesity management programs were operated, aimed at reducing weight, BMI, body fat percentage and so on. This study was conducted to review the features of studies in obesity management programs and systematically assess the effects which were published from 1995 to 2006 in Korea. Databases were systematically searched for published data in Korea. It were KISS (Korean studies information services system) and KERIS (Korean Education research information system), which were major literature search systems for all academic fields in Korea. Total 114 studies were initially identified, of which 21 satisfied our inclusion data. The effects of obesity management programs were assessed on the results in weight, BMI (body mass index), HDL (high density lipids), body fat percentage, self-efficacy. Effect size estimated on the equation of M1 - M2 / Sp, where M1 was mean of the experimental group, M2 was the mean of control group, and Sp was the pooled standard deviation. Magnitude of effect size was interpreted by using Cohen's definition. Cohen described small, medium, and large effect sizes as 0.2, 0.5, and 0.8 respectively. The studies about obesity management programs were the most published in 2005(26.1%). Obesity management programs were popularly operated as the type of 12 weeks intervention, exercise intervention(52.4%), quasi-experimental study(85.7%). Ten studies reported significant effects on weight, and nine studies reported significant effects on BMI and HDL. Only five and three studies reported significant effects on body fat percentage and self-efficacy respectively. The effects of each outcome were generally significant when the studies included these elements, intervention over 10 weeks, evaluation over 3 times, a comprehensive program (exercise, nutrition education, behavior modification) and reinforcing factors (self-monitoring, group discussion, one's goal setting, and etc.). Effective obesity management programs should contain these essential elements and objectives of obesity management programs must be set out evident at the beginning. The participants should be registered, educated and evaluated by continuous obesity management programs.