• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2005년도 춘계학술발표회
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• pp.67-72
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• 2005

본 연구는 우리나라 RCC/RSC의 효율성을 2개의 투입자료와 4개의 산출자료를 이용하여 DEA법을 이용하여 측정하였고, 정성적 자료는 전문가로 평가하였다. 또한 이러한 자료를 통합하기 위한 방법은 의사결정지원 시스템인 퍼지로직을 적용하였고, 이 평가방법을 이용하여 RCC/RSC의 운영효율성의 우선순위를 평가하였다. 그 결과 인천, 목포, 제주, 동해, 부산, 포항, 여수, 속초, 통영, 울산, 태안, 군산 RSC 순으로 효율성이 높은 것으로 나타났다.

• Structural Monitoring and Maintenance
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• 제2권2호
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• pp.95-113
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• 2015

The knowledge of the behavior of any roller compacted concrete (RCC) dam and its foundation is gained by studying the service action of the dam and its foundation using measurements of an external and internal nature. The information by which a continuing assurance of structural safety of the RCC dam can be gauged is of primary importance. Similarly, the fact that the information on structural and thermal behavior and the properties of concrete that may be used to give added criteria for use in the design of future RCC dams is of secondary importance. Wide spread attention is now being given to the installation of more expensive instrumentation for studying the behavior of concrete dams and reservoirs and forecasting of any adverse trends. In view of this, the paper traces installation and need of the comprehensive instrumentation scheme implemented to monitor the structural and thermal behavior of 102.4 m high RCC dam constructed near Mumbai in India. An attempt is made in the present paper to emphasize the need to undertake an instrumentation program and evaluate their performance during construction and post construction stage of RCC structures. Few typical results, regarding the thermal and structural behavior of the dam, obtained through instrumentation installed at the dam site are presented and compared with the design considerations. The fair agreement is seen in the response observed through instrumentation with that governing the design criteria.

• Advances in concrete construction
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• 제10권6호
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• pp.489-498
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• 2020

This paper investigates mechanical properties of roller compacted concrete (RCC) involving reclaimed asphalt pavement (RAP). In this way, a set of 276 cylindrical RCC specimens were prepared with different RAP sizes (i.e., fine, coarse & total) at various ratios (i.e., 10%, 20%, and 40%). Results reveal that incorporation of RAP decreases unconfined compressive strength (UCS), modulus of elasticity (E), and indirect tensile (IDT) strength of RCC. For each RAP size, a regression model was used to maximize RAP content while satisfying the UCS lower limit (27.6 Mpa) mentioned by ACI as a minimum requirement for RCC used in pavement construction. Moreover, UCS of RAP incorporated mixes, dissimilar to that of control mixes, was found to be sensitive and insensitive to the testing temperature and curing time after 7 days, respectively. The results also demonstrate that the higher amounts of RAP, the more flexibility in RCC is. This issue was also proved by the results of modulus of elasticity test. In addition, the toughness index (TI) shows that increase in RAP content leads to up to 43% increase in energy absorbance capacity of RCC.

• Advances in concrete construction
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• 제12권5호
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• pp.411-418
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• 2021

Roller compacted concrete (RCC) used in the island reef airport runway will be subjected to the coupling actions of the fatigue impacts and the salt spray cycles, which will accelerate the deterioration of runway concrete and even threaten the flight safety. A cyclic impact testing machine and a climatic chamber were used to simulate the low-velocity fatigue impact and the salt spray cycles, respectively. The physical properties, the microstructures and the porosity of RCC were investigated. The results show the flexural strength firstly increases and then decreases with the increase of the fatigue impacts and the salt spray cycles. However, the decrease in the flexural strength is significantly earlier than the compressive strength of RCC only subjected to the salt spray cycles. The chlorine, sulfur and magnesium elements significantly increase in the pores of RCC subjected to 30000 fatigue impacts and 300 salt spray cycles, which causes the decrease in the porosity of RCC. The coupling effects of the fatigue impacts and the salt spray cycles in the later period accelerates the deterioration of RCC.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.531-534
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• 1996

In this work, we investigate the characteristics of output compliance matrix of a planar 3 degree-of-freedom parallel mechanism when joint compliances are attached to the mechanism redundantly. It is shown by simulation that by attaching redundant joint compliances symmetrically to the mechanism, the translational and rotational compliances can be arbitrarily modulated within some ranges. This property could be effectively used in the control of the compliance characteristics of actively adjustable RCC devices.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.718-721
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• 1996

In this work, an effective stiffness generated by internal loading for a planar 3 degrees of freedom RCC mechanism is investigated. For this purpose, the internal kinematic analysis and antagonistic stiffness modeling for this mechanism are performed. It is shown that the antagonistic stiffness could be effectively created at the center of the mechanism in its symmetric configuration.

• 한국도로학회논문집
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• 제19권6호
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• pp.37-46
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• 2017

PURPOSES : A composite pavement utilizes both an asphalt surface and a concrete base. Typically, a concrete base layer provides structural capacity, while an asphalt surface layer provides smoothness and riding quality. This pavement type can be used in conjunction with rollercompacted concrete (RCC) pavement as a base layer due to its fast construction, economic efficiency, and structural performance. However, the service life and functionality of composite pavement may be reduced due to interfacial bond failure. Therefore, adequate interfacial bonding between the asphalt surface and the concrete base is essential to achieving monolithic behavior. The purpose of this study is to investigate the bond characteristics at the interface between asphalt (HMA; hot-mixed asphalt) and the RCC base. METHODS : This study was performed to determine the optimal type and application rate of tack coat material for RCC-base composite pavement. In addition, the core size effect, temperature condition, and bonding failure shape were analyzed to investigate the bonding characteristics at the interface between the RCC base and HMA surface. To evaluate the bond strength, a pull-off test was performed using different diameters of specimens such as 50 mm and 100 mm. Tack coat materials such as RSC-4 and BD-Coat were applied in amounts of 0.3, 0.5, 0.7, 0.9, and $1.1l/m^2$ to determine the optimal application rate. In order to evaluate the bond strength characteristics with temperature changes, a pull-off test was carried out at -15, 0, 20, and $40^{\circ}C$. In addition, the bond failure shapes were analyzed using an image analysis program after the pull-off tests were completed. RESULTS : The test results indicated that the optimal application rate of RSC-4 and BD-Coat were $0.8l/m^2$, $0.9l/m^2$, respectively. The core size effect was determined to be negligible because the bond strengths were similar in specimens with diameters of 50 mm and 100 mm. The bond strengths of RSC-4 and BD-Coat were found to decrease significantly when the temperature increased. As a result of the bonding failure shape in low-temperature conditions such as -15, 0, and $20^{\circ}C$, it was found that most of the debonding occurred at the interface between the tack coat and RCC surface. On the other hand, the interface between the HMA and tack coat was weaker than that between the tack coat and RCC at a high temperature of $40^{\circ}C$. CONCLUSIONS : This study suggested an optimal application rate of tack coat materials to apply to RCC-base composite pavement. The bond strengths at high temperatures were significantly lower than the required bond (tensile) strength of 0.4 MPa. It was known that the temperature was a critical factor affecting the bond strength at the interface of the RCC-base composite pavement.

• The Korean Journal of Physiology and Pharmacology
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• 제20권3호
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• pp.297-304
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• 2016

Klotho functions as a tumor suppressor predominantly expressed in renal tubular cells, the origin of clear cell renal cell carcinoma (ccRCC). Altered expression and/or activity of growth factor receptor have been implicated in ccRCC development. Although Klotho suppresses a tumor progression through growth factor receptor signaling including insulin-like growth factor-1 receptor (IGF-1R), the role of Klotho acting on IGF-1R in ccRCC and its clinical relevance remains obscure. Here, we show that Klotho is favorable prognostic factor for ccRCC and exerts tumor suppressive role for ccRCC through inhibiting IGF-1R signaling. Our data shows the following key findings. First, in tumor tissues, the level of Klotho and IGF-1R expression are low or high, respectively, compared to that of adjacent non-neoplastic parenchyma. Second, the Klotho expression is clearly low in higher grade of ccRCC and is closely associated with clinical outcomes in tumor progression. Third, Klotho suppresses IGF-1-stimulated cell proliferation and migration by inhibiting PI3K/Akt pathway. These results provide compelling evidence supporting that Klotho acting on IGF-1R signaling functions as tumor suppressor in ccRCC and suggest that Klotho is a potential carcinostatis substance for ccRCC.

• Asian Pacific Journal of Cancer Prevention
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• 제14권1호
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• pp.315-320
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• 2013

Background: TGF-${\beta}$-activated kinase-1 (TAK1) has been found to be over-expressed in a variety of solid malignancies and related to tumor growth. The aim of this study was to evaluate the expression level of TAK1 in clear cell renal cell carcinoma (ccRCC) and assess its value as a novel prognostic marker. Methods: TAK1 mRNA was assessed in 51 paired ccRCC tissues and adjacent normal tissues (ADTs) by real-time PCR. Tissue TAK1 protein was also assessed in 91 ADTs and 177 samples of ccRCC immunohistochemically for evaluation of relationships with clinical characteristics. Results: RT-PCR showed that TAK1 RNA level was significantly higher in ccRCC tissues than in the paired ADTs and immunohistochemistry confirmed higher expression of TAK1 protein in ccRCC samples compared with ADTs. TAK1 protein expression in 177 ccRCC samples was significantly correlated with T stage, N classification, metastasis, recurrence and Fuhrman grade, but not age and gender. Patients with low TAK1 levels had a better survival outcome. TAK1 expression and N stage were independent prognosis factors for the overall survival of ccRCC patients. Conclusions: Overexpression of TAK1 predicts a poor prognosis in patients with ccRCC, so that TAK1 may serve as a novel prognostic marker.

• Asian Pacific Journal of Cancer Prevention
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• 제15권18호
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• pp.7925-7928
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• 2014

Purpose: Renal cell carcinoma (RCC) is increasingly being recognized as a metabolic disease in recent studies. The aim of the present study was to identify the prevalence of metabolic syndrome (MetS) and its association with RCC among urologic patients. Materials and Methods: The study included a total of 355 participants (117 adult RCC patients and 238 age matched controls) divided into groups, with and without MetS diagnosed using the criteria of the American Heart Association/The National Heart Lung and Blood Institute. Groups were compared statistically and logistic regression analysis was performed to investigate the impact of MetS criteria on RCC risk. Results: Of the 117 RCC patients, 52 (44.4%) and of the 238 controls, 37 (15.5%) had MetS. A significant association (p<0.001) was found between the presence of MetS and RCC (OR: 4.35; 95% CI=2.62-7.21). As the number of MetS components accumulated from 3 to 5, RCC risk increased likewise from 4 to 6 times. Conclusions: MetS is more prevalent in RCC patients in Turkey compared to controls. Risk increases with the number of coexisting MetS components.