• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3320-3325
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• 2023

The scaled water-cooled Reactor Cavity Cooling System (RCCS) experimental facility reproduces a passive safety feature to be implemented in Generation IV nuclear reactors. It keeps the reactor cavity and other internal structures in operational conditions by removing heat leakage from the reactor pressure vessel. The present work uses Flownex one-dimensional thermal-fluid code to model the facility and predict the experimental thermal-hydraulic behavior. Two representative steady-state cases defined by the bulk volumetric flow rate are simulated (Re = 2,409 and Re = 11,524). Results of the cavity outlet temperature, risers' temperature profile, and volumetric flow split in the cooling panel are also compared with the experimental data and RELAP system code simulations. The comparisons are in reasonable agreement with the previous studies, demonstrating the ability of Flownex to simulate the RCCS behavior. It is found that the low Re case of 2,409, temperature and flow split are evenly distributed across the risers. On the contrary, there's an asymmetry trend in both temperature and flow split distributions for the high Re case of 11,524.

• Advances in nano research
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• 제14권2호
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• pp.165-177
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• 2023

Nanomotors are gaining popularity as novel drug delivery methods since they can move rapidly, penetrate deeply into tissues, and be regulated. The ability of manufactured nanomotors to swiftly transport therapeutic payloads to their intended location constitutes a revolutionary nanomedicine strategy. The nanomotors for the drug delivery purpose are released in the blood flow under the different physical conditions, so the stability investigation of these devices is essential before the production, especially in the sport and physical exercise conditions that the blood flow enhances. As a result, using dynamic analysis, this article investigates the stability of the nanomotor released in the blood flow when sport and physical activity circumstances increase blood flow. The considered nanodevice is made of a central motor, and nanotubes are used for the nanomotor blade, which is the drug capsule. Finally, the stability examination of nanomotor as the drug delivery equipment is discussed in detail, and the proposed results can present beneficial results in designing and producing small-scale intelligent devices.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2002년도 학술논문발표회
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• pp.97-102
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• 2002

The ability to pass between bars is one of the most important performance of self-compacting concrete or high-flowability concrete since it determines the final filling capacity which influences the strength and durability of hardened concrete in structure. Therefore it has been evaluated by many researchers using different kinds of testing apparatuses. The assessments of passing ability, however, differ largely according to the style, the dimension and the criteria in apparatuses, and the value obtained from one apparatus cannot be converted those of the others. There needs a rheological approach to the better understanding of the passing behavior of fresh concrete between reinforcing bars, where the flow velocity of concrete becomes slow and the blockade sometimes occurs due to the interference between aggregates and reinforcing bars. Experimental works were conducted to clarity the effects of the clearance between reinforcing bars, the volume of aggregate and the rheological properties of matrix on the behavior from the rheological point view and showed the rational mix proportioning of concrete.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.41-44
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• 2006

The objective of this study was to evaluate the stabilization of As and heavy metals in tailings from the Samkwang Au-Ag mine with $Ca(OH)_2$. In order to evaluate the stabilization ability of As and heavy metals in the tailings, column test was implemented with various conditions as 1) particle size of $Ca(OH)_2$, 2) mixing method and 3) flow rate of eluents during 60 days. The results showed that addition with 5% of $Ca(OH)_2$ in 1kg of the tailings had the most effective ability of stabilization up to 95%. In addition, stabilization ability of As and heavy metals in tailings was enhanced using a fine powder of $Ca(OH)_2$. Therefore, stabilization technology can be used as a remediation of As and heavy metals in mine wastes including tailings and a nearby soils from abandoned metal mines.

• 한국산학기술학회논문지
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• 제18권2호
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• pp.268-276
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• 2017

본 연구의 목적은 대학 골프선수들을 대상으로 운동능력믿음, 성취목표성향, 운동몰입 및 인지된 경기력의 이론적 관계를 검증하는데 있다. SPSS 18.0과 AMOS 18.0 통계 프로그램을 활용하여 대학교에 재학 중인 211명의 골프선수들로부터 수집한 자료를 분석한 결과는 다음과 같다. 첫째, 대학 골프선수들이 갖고 있는 운동 능력에 대한 믿음의 하위요인에서 증가된 믿음은 과제성취성향에(C.R.=3.780, p<.001) 영향을 주는 것으로 밝혀졌다. 둘째, 대학 골프선수들의 성취목표성향에서 과제성취성향(C.R.=4.082, p<.001)과 자아성취성향(C.R.=3.819, p<.001)은 골프에 대한 몰입감을 높이는 것으로 나타났다. 셋째, 대학 골프선수들의 성취목표성향의 하위 요인에서는 과제성취성향(C.R.=3.020, p<.01)만이 인지된 경기력을 향상시키는 것으로 나타났다. 넷째, 대학 골프선수들의 운동몰입이 높을수록 인지된 경기력의 수준도 좋아지는 것으로 나타났다(C.R.=4.642, p<.001). 다른 하위요인들은 통계적으로 유의한 수준에서 검증되지 못했다. 이러한 연구결과는 선수 자신의 운동능력에 대한 믿음에 따라 경기력이 변화될 수 있음을 알려주는 것으로서, 다양한 스포츠 분야에 적용이 가능할 것으로 보인다.

• 한국소음진동공학회논문집
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• 제24권3호
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• pp.189-197
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• 2014

윗면에 개구부가 있는 쐐기 상자 모양으로 단순화 된 모델은 현대자동차에서 버페팅 현상을 구현하기 위해 사용되었다. 제안된 조건에서 수행한 측정값들은 버페팅 예측을 통해 CFD의 성능을 검증하기 위함이었다. PowerFLOW를 이용하여 얻어진 버페팅 해석 결과와 개구부가 없는 상태에서의 윗면의 경계층 발달을 이 논문에 기술하였다. 실험에서 측정된 음압은 유동 메커니즘을 통해 기술 하였고, 유동구조를 잘 묘사할 수 있도록 개선된 셋업을 통해 측정된 음압에 근사한 결과를 얻을 수 있었다.

• 디지털융복합연구
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• 제16권5호
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• pp.221-229
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• 2018

기계 학습 및 인공지능은 제 4차 산업혁명의 핵심 기술이다. 하지만 프로그래밍 능력을 요구하는 기계 학습 플랫폼의 특성 상 일반 사용자들의 접근이 힘들기 때문에 인공지능이나 기계학습의 대중화는 제한을 받고 있다. 본 연구에서는 그래픽 사용자 인터페이스(Graphic User Interface, GUI)를 도입하여 이러한 한계를 극복하고 인공지능 활용에 대한 일반인의 접근성을 향상시키고자 하였다. 기본 기계 학습 플랫폼으로는 Tensorflow를 채택하였고 GUI는 마이크로 소프트 사의 .Net 환경을 활용하여 작성하였다. 새로운 사용자 인터페이스를 이용하면 일반 사용자도 파이썬 프로그래밍에 대한 부담없이 직관적으로 데이터를 관리하고, 알고리즘을 적용하고, 기계 학습을 실행할 수 있다. 우리는 이 개발이 다양한 분야에서의 인공지능 개발에 기초가 되는 자료로 활용되었으면 한다.

• 콘크리트학회논문집
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• 제12권2호
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• pp.99-107
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• 2000

This research investigates experimentally an effect on the properties of the high flowing concrete to be poured in the under-ground slurry wall of Inchon LNG receiving terminal(#213,214-TK) according to variations of concrete materials. Variables for sensitivity test were selected items as followings. 1) Concrete temperature (3cases), 2) Unit water (5cases), 3) Fineness modulus of fine aggregate (5cases), 4) Particle size of lime stone powder (3cases), 5) Replacement ratio of blast-furnace slag (4cases) and 6) Addition ratio of high range water reducing agent (5cases). And fresh conditions of the super flowing concrete should be satisfied with required range including slump flow(65$\pm$5cm), 50cm reaching time of flow(4~10sec), V-lot flowing time(10~ 20sec), U-box height(min. 300mm) and air content(4$\pm$1%). As results for sensitivity test, considered flow-ability, self-compaction and segregation resistance of the high flowing concrete, material variations and conditions of fresh concrete should be satisfied with the range as follwings. 1) Concrete temperature are 10~2$0^{\circ}C$(below 3$0^{\circ}C$), 2) Surface moisture of fine aggregate is within $\pm$ 0.6%, 3) Fineness modulus of fine aggregate is 2.6$\pm$0.2, 4)Replacement ratio of blast-furnace slag is 45~50% and 5) Addition ratio of high range water reducing agent is within 1%. Based on the specification for quality control, we successfully finished concrete pouring on the under-ground slurry wall having 75,000㎥(#213,214-TK) and accumulated real date in site.

• 품질경영학회지
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• 제42권3호
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• pp.325-338
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• 2014

Purpose: The purpose of this study was to explain de-painting phenomenon of KUH-1 tail blade and to propose useful solution of it by test. The proposed solution was evaluated by real flight, and then it applied to mass product to improve the paint qual ity of KUH-1 tail blade. Methods: This study investigated an adhesive ability of primer following surface sanding condition. The cross cut and scratch test were conducted to evaluate the adhesive strength. And the water flow test was designed to simulate a real flight condition under rain. Through water flow test, an optimal condition of tail blade to prevent a de-painting phenomenon was deduced. Finally, the improvement method was evaluated by real flight under rain. Results: The results of this study are as follows; The sequential polishing was most excellent method in primer painting quality. The results of test including cross cut, scratch and water flow showed that MIL-DTL-53039 paint with epoxy primer has excellent adhesive ability. To proof the effect of improvement, a real flight during a rain condition was conducted. Finally, the comparison between original and improved configuration was conducted. Conclusion: The painting quality of KUH-1 tail blade was improved through deriving an optimal painting condition. In detail, a condition of optimal sanding and a sort of primer and paint was showed. Finally, the reliability of tail blade was guaranteed through improving the quality of painting.

• 한국건축시공학회지
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• 제15권2호
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• pp.153-160
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• 2015

본 연구는 대리석가공과정에 발생하는 부산물인 폐 대리석 분말을 고유동 콘크리트의 유동성, 충전성 및 강도특성에 어떠한 영향을 주는지를 분석하였다. 실험결과, 폐 대리석 분말을 혼입한 굳지 않은 고유동 콘크리트 특성을 살펴보면 유동성이 증가하였고, 재료분리 저항성, 충전성이 우수하였다. 또한 경화한 고유동 콘크리트에서 압축강도는 폐 대리석 분말의 치환율 15%까지 모든 재령에서 압축강도가 증가하여 폐 대리석 분말의 최적 치환율은 15% 이내가 적정할 것으로 판단된다. 이상의 실험결과를 바탕으로 폐 대리석 분말을 고유동 콘크리트의 충전재로 활용하면 산업부산을 활용할 수 있어 환경오염방지와 콘크리트 제조시 원가절감의 이점을 동시에 달성할 수 있을 것으로 판단된다.