• Title/Summary/Keyword: Reinforcing

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Flexural Behavior of FRP Bar Reinforced HSC Beams with Different Types of Reinforcing Bar and Fiber (이질 보강근 및 섬유와 함께 보강된 FRP 보강근 보강 고강도 콘크리트 보의 휨 거동)

  • Yang, Jun-Mo;Shin, Hyun-Oh;Min, Kyung-Hwan;Yoon, Young-Soo
    • Journal of the Korea Concrete Institute
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    • v.23 no.3
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    • pp.273-280
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    • 2011
  • Ten high-strength concrete beam specimens, which have various combinations of different types of flexural reinforcement and short fibers were constructed and tested. Six beams were reinforced with two layers of steel, CFRP, and GFRP bar combinations. The other four beams were reinforced with two layers of single type CFRP and GFRP bars, with steel and synthetic short fibers. An investigation was performed on the influence of the parameters on the load-carrying capacity, post cracking stiffness, cracking pattern, deflection behavior, and ductility. The low post cracking stiffness, large deflection, deep crack propagation, large crack width, and low ductility of FRP bar-reinforced beams were controlled and improved by positioning steel bars in the inner layer of the FRP bar layer. In addition, the addition of fibers increased the first-cracking load, ultimate flexural strength, and ductility as well as the deep propagating cracks were controlled in the FRP bar-reinforced concrete beams. The increased ultimate concrete strain of fiber-reinforced concrete should be determined and considered when FRP bar-reinforced concrete members with fibers are designed.

A Study on Shear Bond Strength of Heat Press Ceramic to Non Precious Porcelain Metal (도재용착용 비귀금속과 열가압성형도재의 전단결합강도 연구)

  • Kim, Seong-Soo;Kim, Wook-Tae;Lee, Myung-Kon
    • Journal of Technologic Dentistry
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    • v.33 no.1
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    • pp.37-45
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    • 2011
  • Purpose: Heat pressed ceramics, used for all ceramic restorations, have the additional advantage of being technically less change through using of the lost-wax technique. Conceptually, combining the ceramic with the clinically proven reinforcing ability of a metal framework would be advantageous; however, cause of mismatching of fusion between ceramics and metal frameworks which from differences of casting temperature and coefficient of thermal expansion, pressed ceramics could not be used with a metal framework. The purpose of this study was to compare shear bond strength of press-to metal ceramic to porcelain fused non precious metal and feldspatic porcelain fused non precious metal. Methods: The 30 metal specimens were casted in a porcelain fused non precious metal nickel-chromium alloy. They were divided into 3 groups by surface treatment and applied ceramic: $125{\mu}m$ aluminium oxide sandblasting and veneered feldspatic porcelain (group FP), $125{\mu}m$ aluminium oxide sandblasting and had press-to-metal ceramic applied (group PC), porcelain bonder (gold bonder) fused on surface of metal specimens and had press-to-metal ceramic applied (group PCG). In each group 10 metal specimens were used. The press-to-metal ceramic applied 20 specimens had ash-free wax pattern applied, the metal-wax complexes invested, and were pressed with heat press ceramic. All specimens were subjected to shear bond strength test at a crosshead speed of 1.0 mm/min. Results: The results of measured in Mean SD and data were analyzed by one-way AVOVA (p= .05) and Tukey HSD test (p= .05).: group FP $16.090{\pm}1.841$ MPa, group PC $12.620{\pm}1.8256$ MPa, group PCG $10.920{\pm}0.9283$, significant differences between all groups (p < .05). Significant differences were found in each between group FP and group PC, group FP and group PCG (p < .05). Conclusion: The shear bond strength of press-to-metal ceramic to porcelain fused non precious metal was described higher in unused gold bonder group than used gold bonder groups.

A Study of the Effects of Health Contracting on Compliance with Health Behaviors in Clients with Hypertension (자가간호증진을 위한 건강계약이 고혈압자의 건강행위 이행에 미치는 영향)

  • 이향련
    • Journal of Korean Academy of Nursing
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    • v.17 no.3
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    • pp.204-217
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    • 1987
  • It is generally accepted that the delivery of health care is undergoing many changes specially those related to acute, contagious disease care and to the increase of chronic illnesses which can not be cured but are controlable. The health care practitioner can not be soley responsible for the control of their clients' care. Because the clients will play a vital role in controlling their illnesses, long term participation by both the health care provider and the client is necessary. Since most individuals with hypertension do not experience signs or symptoms, the disease is difficult to detect and even when diagnosed, clients do not comply well with their hypertension regimens. The noncompliant client is at increased risk for compliants involving the heart, brain, kidney and other organs. In an effort to explore methods of increasing patient participation in and adherence to treatment programs for hypertension, the researcher used health contracting to promote self care. The research questions are; 1) Will the health contracting increase compliance in health behavior and reduce the blood pressure\ulcorner 2) If clients comply with their regimens will this reduce their blood pressure\ulcorner The research design utilized in this study was a quasi-experimental design. A purposive sample, was abtained from two churches in the 1. area, consisting of 64 clients with hypertension. The data was collected from the middle of January to the 1st of September 1985. Randomization was only of the two church groups into experimental and control groups. Compliance with health behavior related to the hypertensive regimen, blood pressure and body weight were measured, compared and analyzed. In the experimental group measurements were made 6 times; one month before the education program after education program when health contracting was done and 4 more times once a month for 4 months. In the control group measurements were made 3 times; one month before the education program after the education program, and once 4 months later. There was no health contracting. The data were analyzed by t-test, Pearson correlation and ANOVA according to purpose of the study. The result of this study may be summarized as follows: The result related to the hypothesis on the effect of health contracting are as follows: H$_1$; “The hypothesis that the experimental group, with a health contractual agreement will demonstrate increased compliance levels for health behavior than the control group” was supported(t=-5.29, df=62, p=.000). H$_2$; “The hypothesis that the experimental group, with a health contractual agreement, will demonstrate a greater reduction in blood pressure than the control group” was supported (for systolic blood pressure t=2.72, df=62, p=.009, for diastolic blood pressure t=1.95, df=62, p=.050). H$_3$; The hypothesis that the greater the compliance of the client with health behavior the lower the client's blood pressure will be was partially supported (for systolic pressure r=-.2981, p=.008, for diastolic pressure r=-.1720, p=.087). From the examination of the results of this study it can be concluded that the interaction between the nurse and the client, contracting to define goals and reinforcing compliant behavior, leads to improved compliance with health care behaviors and thus to an increase in the effectiveness of nursing care. Further consideration need to be given to the inclusion of the concept of health contracting in primary nursing and to further research in this area.

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Shear Resisting Effects of Protruded Nails by Pressure Grouting (가압식 돌기네일의 전단저항 효과)

  • Hong, Cheorhwa;Lee, Sangduk
    • Journal of the Korean GEO-environmental Society
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    • v.18 no.7
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    • pp.13-20
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    • 2017
  • Soil nailing is ground reinforcement method using the shear strength of ground and the pullout shear resistance force of nail. It is mainly used for reinforcement of cut slopes, earth retaining structures and retaining walls, etc. It may be designed considering the pullout resistance of nail in the case of earth retaining structure and retaining wall, but it should be designed considering not only pullout resistance but also shear and bending resistance in the case of slope. However, conservative designs considering only pullout resistance are being done and most of the studies are about increasing pullout resistance by improving of material, shape and construction method of nail. Actually, Shear bending deformations occur centering on the active surface in ground reinforced with the nail. The grout with relatively low strength is destroyed and separated from the reinforcing material. As a result, the ground is collapsed while reducing the frictional resistance rapidly. Therefore, it is necessary to develop the method to increase the shear resistance while preventing separation of nail and grout body. In this study, an experimental study was conducted on new soil nailing method which can increase shear resistance by forming protrusions through pressurized grouting after installing a packer on the outside of deformed bar.

The Development Device of the Local Food Industry - Focusing on Local Food CEOs in Daejeon.Chungnam Province - (향토음식 산업의 발전 방안 - 대전.충청지역 향토음식경영주를 중심으로 -)

  • Kim, Keun-Jong
    • Culinary science and hospitality research
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    • v.16 no.1
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    • pp.78-91
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    • 2010
  • This study aims to find a way of developing the local food industry by examining CEOs who run local food restaurants. As a result of researching the local food of Daejeon and the Chungnam province, there were 106 kinds of local food. However, all the CEOs of local food restaurants were having difficulty in operating. In order to survey the local food restaurants for development devices, 450 copies of the questionnaire were distributed to man- or woman-CEOs who operate a local food restaurant in Daejeon city and the Chungnam province. Among 450 copies of the distributed questionnaire, 390 copies were collected for this study. It used a total of 370 copies as the effective samples for an empirical analysis except 20 copies with false entries among them. The result of the empirical analysis showed as follows: 1) For the recognition of the local food, there was not difference between males and females. 2) For the factor of success on the local food restaurants, both males and females answered food taste was most important. 3) For the reason why chain business of the local food restaurants was difficult, both males and females answered there were too many side dishes coming with a main dish. 4) For the way of reinforcing competitive power of the local food restaurants, most of the male respondents and all females thought there should be financial support.

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Shake Table Response and Analysis of RC Bridge Piers with Lap-Spliced Steel under NFGM (주철근 겹침이음된 RC교각의 근단층지반운동에 대한 진동대 응답과 분석)

  • Chung, Young-Soo;Park, Chang-Young;Hong, Hyun-Ki;Park, Ji-Ho;Shim, Chang-Su
    • Journal of the Korea Concrete Institute
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    • v.20 no.4
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    • pp.451-458
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    • 2008
  • The near-fault ground motion (NFGM) is characterized by a single long period velocity pulse of large magnitude. NFGM's have been observed in recent strong earthquakes, Izmit Turkey (1999), Kobe Japan (1995), Northridge USA (1994), etc. These strong earthquakes have caused considerable damage to infrastructures because the epicenter was close to the urban area, called as NFGM. Extensive research for the near-fault ground motion (NFGM) have been carried out in strong seismic region, but limited research have been done for NFGM in low or moderate seismic regions because of very few records. The purpose of this study is to investigate and analyze the effect of near-fault ground motions on reinforced concrete (RC) bridge piers with lap-spliced longitudinal reinforcing steels. The seismic performance of four RC bridge piers under near-fault ground motions was investigated on the shake table. In addition, a RC bridge pier is subjected to pseudo-dynamic loadings. Test results showed that large residual displacements were observed in RC bridge piers under NFGM. RC specimens on the shake table failed at relatively low displacement ductility, compared with the displacement ductility of RC bridge pier subjected to pseudo-dynamic loadings.

Comparison of Test Methods for Evaluation of Chloride Diffusion Coefficient in Concrete (콘크리트의 염소이온 확산계수 평가를 위한 시험방법 비교)

  • Lee, Chan-Young;Kim, Hong-Sam;Kim, Jin-Cheol;Cheong, Hai-Moon;Ahn, Tae-Song
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.581-584
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    • 2008
  • Generally, durability of concrete structures under marine environment is grossly declined by detrimental ions such as chlorides, which penetrate concrete and was diffused to corrode reinforcing rod. Therefore, chloride diffusion properties in concrete are important for durability evaluation and design of concrete structure. For estimation of chloride diffusion coefficient in concrete, both evaluation methods are used for steady state and non-steady state derived from Fick's 1st and 2nd law, respectively. However, as it is very difficult to evaluate diffusion coefficient for non-steady state like service environment where concrete is actually exposed, indirect evaluation method by laboratory accelerated test is generally used. In this study, comparison of chloride diffusion behavior was investigated for fixed mix proportion and age of concrete using four accelerated test methods based on domestic and foreign standards. From test results, only relative comparison between concrete mixtures was possible using ASTM C 1202 test, and diffusion coefficient for steady state was estimated as low as 1/10 of that for non-steady state. In addition, diffusion coefficient estimated by immersion test was similar to result by NT build 492 test.

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An Analysis of Efficiency in Major University Hospitals in Domestically Capital Area Through DEA Analysis (DEA분석을 통한 국내 수도권 주요 대학병원의 효율성 분석)

  • Park, Byeong-Tae;Lee, Dong-Hyeon
    • Korea Journal of Hospital Management
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    • v.16 no.4
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    • pp.35-66
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    • 2011
  • This study analyzed efficiency by utilizing DEA analytical technique centering on materials for 2009 of 20 major university hospitals in capital area. Input variables were utilized professor & full-time doctor, resident, nurse & number of bed hospitals. Output variables were analyzed by dividing number of annual outpatients & number of annual inpatients, and annually total outpatient profit & inpatient profit into a model of the standard for number of patients and the standard for medical profit. DEA analysis was elicited efficiency score by applying CCR, BCC, BFG, scale profit, and SE model. Through t-test after eliciting efficiency score, the implications were suggested by comparing efficiency between DMU in Seoul and DMU in capital area, by comparing between high-class general hospitals and general hospitals, and by comparing between high-class general hospitals in Seoul and 5 big hospitals. As a result of analysis, the major university hospitals in capital area showed high efficiency as a whole close to "1," but indicated low efficiency relatively in CCR field. Thus, the expansion in scale within capital area was indicated to reach the limit. Second, in a model of analyzing the standard for number of patients, the medical institutions, which are being operated efficiently, were indicated to be 10 DMUs. In the standard for medical profit, 12 DMUs were analyzed to be operated efficiently. Third, the efficiency in general hospital was higher than high-class general hospital. Thus, the efficiency of operation was indicated to be more important than scale. Also, large high-class hospitals(big 5) where are located in downtown Seoul showed the higher efficiency than other general high-class general hospitals, but were indicating very low efficiency in some DMUs. Fourth, as a result of generalizing and evaluating the number of patients and the medical profit, the efficient DMU was indicated to be more when analyzing on the basis of medical profit than the standard for number of patients. Thus, major university hospitals in capital area were indicated to make more effort for section in medical profit. Based on the analytical results of efficiency, a strategy for reinforcing efficiency in inefficient DMU was indicated to be needed a strategy of creating customers for promoting number of patients and a strategy for making operation efficient for increasing profitability.

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A Study on Job Rotation in Civil Service (공무원 순환보직에 관한 연구)

  • Kim, Kwang-ho
    • KDI Journal of Economic Policy
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    • v.30 no.2
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    • pp.61-97
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    • 2008
  • This paper aims at analyzing the practice of job rotation in the Korean government and putting forward policy suggestions. The Korean government is often accused of low capacity and weak competitiveness, which mainly result from the low expertise of public officials. Considering the high quality of human resources flowing into the public sector in Korea, solutions should be found from the structure of the system. This paper regards frequent position changes due to excessive job rotation as a key factor undermining the accumulation of expertise and conducts in-depth analyses. The current practice of frequent rotation shows that the average tenure period of government officials at director level and above is only about one year, far shorter than those in major developed countries, which causes many problems such as low efficiency, lack of accountability and policy consistency, and low opportunity for accumulating expertise. Simple models are set up to analyze job rotation and other alternative personnel management systems. Analyses find that it would be desirable to have each individual experience various positions during the initial rotation period to find his/her own aptitude, and then accumulate expertise by settling in at a certain specialized field for a prolonged period of time based on the revealed aptitude in mid and high positions. This turns out to be in line with the structure of the Career Development Program which is being introduced. The model-based analysis of this paper distinguishes this study from preceding ones conducted in the traditional framework of personnel management study. Practical measures to mitigate the problems of frequent job rotation include rotating within the area of specialty, narrowing the scope of transfer, and reinforcing the minimum tenure period. However, since the current frequent rotation is fundamentally attributable to the rank system based on seniority, the present civil service classification system needs to be converted into a position classification system in the long run.

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Evaluation on Stress-Strain-Strength Behavior of the Textile Encased Soils via Triaxial Compression Tests (삼축압축시험을 통한 섬유로 구속된 흙의 응력-변형률-강도 거동 평가)

  • Yoo, Wan-Kyu;Kim, Byoung-Il;Cho, Wanjei
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.2
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    • pp.643-653
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    • 2013
  • Recently, there are an increasing number of studies on the method of wrapping the outer wall of granular piles with geosynthetic fibers such as geotextile or geogrid that has a certain level of tensile strength as an alternative method for the ground improvement techniques. In this study, triaxial compression tests are performed on the sand and clay specimen encased with various textiles to evaluate the reinforcing effect with regard to the tensile strength of the textile. Furthermore, triaxial compression tests are performed on the clay specimen inserted by sand only and sand encased with geosynthetics to compare behavioral differences between the conventional sand compaction pile and geosynthetic encased sand pile with regard to the replacement ratio, ${\alpha}_s$ and the tensile strength of the geosynthetics. Based on the experimental results, the strength enhancement due to the textile is affected by the longitudinal tensile strength rather than the transverse one of the applied textile. The effect of the confinement by the textile encasement results in the large increase of the cohesions. The overall behaviors, such as shear strength, pore pressure parameter at failure and stress ratio, of the geosynthetic encased sand pile is quite different from those of the conventional sand compaction pile.