Estimation Model of Residual Water Evaporation During Vacuum Drying

Seunghwan Yu,Kyoung-sik Bang 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2

For the decommissioning or continuous long-term power generation of nuclear power plants, it is necessary to transfer the spent nuclear fuel from the wet storage pool to the dry storage. Spent nuclear fuel should go through the drying process, which is the first step of dry storage. The most important part in the drying process is the removal of the residual water. The spent fuel might be stored in a dry storage system for a long time. The integrity of internal components and spent fuel cladding should be maintained during the storage period. If residual water is present, problems such as aging of metal materials, oxidation of cladding, and the hydride-reorientation could occur. The presence or absence of residual water after vacuum drying is evaluated by pressure. If there is residual water in the vacuum drying process, it evaporates easily at low pressure to form water vapor pressure and the internal pressure rises. In the recent EPRI High burn up demonstration test, the gas inside the canister that satisfied the dryness criteria was extracted and analyzed. It showed that the water content was higher than the expected value. We are conducting verification studies on the pressure evaluation method, which is an indirect evaluation method of vacuum drying. The vacuum drying test was performed on small specimens at Sandia National Laboratory, and quantitative residual water evaluation was also performed. The report did not mention a detailed method for the assessment of residual water. Based on the test results of SNL, direct residual water evaluation was performed using energy balance. If the dryness criteria were satisfied, the quantitative amount of residual water was also evaluated. As a result, almost the same result as the evaluation result of SNL was derived, and it was confirmed that most of the water was removed when the dryness criteria was satisfied.

Preliminary Design of Thermal Test Equipment of Dry Canister for Equivalent Fuel Assembly

Seunghwan Yu,Doyun Kim 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

The temperature of the spent fuel cladding is the basis for the evaluation of integrity. It is almost impossible to directly measure the temperature of spent nuclear fuel. Because spent nuclear fuel is dangerous. We are preparing a test to measure the cladding temperature with an equivalent fuel assembly by simulating the characteristics of spent nuclear fuel. PLUS7 was selected as the test target in consideration of the amount of generation, thermal water retention, residual moisture content, and manufacturability of domestic spent nuclear fuel. The nuclear fuel assembly is planned to be manufactured in two main ways. Except for the cladding tube that simulates decay heat, the structure will be manufactured by KEPCO Nuclear Fuel, and fuel rods and canisters will be manufactured by SUKEGAWA Electric in Japan. The same nuclear fuel assemblies as commercial skeleton will be applied. The temperature of the fuel cladding will be measured by attaching a thermocouple directly to the surface of the cladding tube. The canister is composed of a basket, a basket supporter, a heater and drain tube, a lead, and an observation window. The working fluid is water and helium, and the maximum pressure inside the canister is 1.1 MPa and the minimum pressure is 0.05 kPa. The maximum temperature of the surface of the cladding was designed to be 500°C, and the maximum temperature of the sealing to keep airtightness was designed to be 250°C. To satisfy this condition, we plan to evaluate the leak rate below 10?5 std.cm3·s?1, which is equivalent to helium tightness. The maximum heat of decay per fuel rod is 13 W, and one assembly is up to 3 kW. Production of the test equipment is expected to be completed in the first half of next year, and testing is scheduled to begin in the second half of next year. The test will evaluate all environments that the spent nuclear fuel may experience, such as dry normal conditions, abnormal conditions, wet conditions, and dry conditions. All data will be used for interpretation verification purposes.

Calculation Procedure of Vacuum Drying for Canister

Seunghwan Yu,Doyun Kim 한국방사성폐기물학회 2021 한국방사성폐기물학회 학술논문요약집 Vol.2021 No.11

부품경량화의 차량성능에 미치는 영향에 대한 연구

유승환(SeungHwan Yu),김정훈(JungHun Kim),손영동(YoungDong Son),김영배(YoungBae Kim) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.11_2

The Automobile suspension system is composed of parts that affect performance of a vehicle such as ride quality, handling characteristics, straight performance and steering effort, etc. Moreover, using the multi Body Dynamic Analysis the cost for the initial design step can be decreased, In the design of a suspension system, usually system vibration and structural rigidity must be considered simultaneously to satisfy dynamic and static requirements simultaneously. In this paper, we study on the effect of the weight reduction of unsprung mass and a suspension part, the control am, especially. Sprung mass and unsprung mass are defined as the design variables, which are varying during the DOE process for the Ride Frequency and the Hop Frequency as a objective.

금속 정밀 주조제품의 소형 결함검사를 위한 딥러닝 모델 성능 비교연구

유승환(Seunghwan Yu),이호준(Hojun Lee),박태준(Taejoon Park),윤종완(Jongwan Yoon),서광원(Kwangwon Seo) 한국HCI학회 2021 한국HCI학회 학술대회 Vol.2021 No.1

금속 정밀 주조제품의 결함 검사 자동화는 스마트 팩토리 확산에 아주 중요한 요소이며 인력에 의존한 검사 공정을 자동화 하기 위해 이미지 분석 영역에서 큰 성과를 올리고 있는 딥러닝 기법의 적용이 필수적이다. 본문에서는 금속 정밀 주조제품의 소형 결함검사를 위한 딥러닝 모델 YOLOv3 와 v5 의 성능을 비교분석함으로써 v5 의 정확도, 판단속도가 v3 보다 더 뛰어난 것을 알 수 있으며, 이는 소형 결함 검사에 적합한 딥러닝 솔루션을 제공한다. 또한 작업자가 사용하기 편리한 UI 를 제공함으로써 본 시스템에 HCI 를 적용한다.

근적외선을 이용한 비파괴 당도 측정 시스템의 GUI 설계

유승환(Seunghwan Yu),소민혁(Min-Hyeok So),한철수(Cheolsu Han),김학윤(Hack-Yoon Kim) 한국정보기술학회 2014 Proceedings of KIIT Conference Vol.2014 No.5

비파괴 당도 측정 시스템은 사과에 외부 빛에너지를 가하고 사과를 통해 나온 변형된 빛에너지를 측정함으로써 사과의 당도를 추정한다 기존 비파괴 당도 측정 시스템의 인터페이스는 대부분 당도 측정 시스템의 기술자를 위하여 설계되었기 때문에 실제 농가에서 일하는 농민이 사용하고 모니터링하기에 어려운 문제점이 있다. 따라서 본 논문에서는 사용자인 농민이 쉽게 이용할 수 있는 비파괴 당도 측정 시스템의 그래픽 유저 인터페이스를 제안한다.

Pharmacokinetics and tolerability of eletriptan hydrobromide in healthy Korean subjects

Kim, Yu Kyong,Shin, Kwang-Hee,Alderman, Jeffrey,Yu, Kyung-Sang,Jang, In-Jin,Lee, SeungHwan Dove Medical Press 2018 Drug design, development and therapy Vol.12 No.-

<P><B>Background</B></P><P>Migraine is one of the most common headache disorders that greatly affect the quality of life. Selective serotonin (5-HT) receptor agonists such as triptamine-based drugs called triptans are used for treatment of migraine.</P><P><B>Purpose</B></P><P>This study aimed to evaluate the pharmacokinetic (PK) and tolerability profiles of eletriptan hydrobromide (eletriptan HBr), a selective 5-hydroxytryptamine (also known as serotonin) 1B/1D receptor agonist, in Koreans and compare the results to those observed in non-Koreans in a previously published study.</P><P><B>Patients and methods</B></P><P>A randomized, open-label, single, and repeated-dose study was conducted in 16 healthy Korean male subjects using a four-treatment, four-period, and four-sequence crossover design (NCT01139515). The subjects received one of the following four treatments in each period: a single dose of 20, 40, 80 mg eletriptan HBr or a repeated oral dose of 40 mg 2 h apart. Blood samples were collected before and up to 26 h after dosing for quantification of plasma eletriptan concentration by high-performance liquid chromatography tandem–mass spectrometry. The PK parameters were estimated using noncompartmental methods. Ethnicity differences between Korean and non-Korean subjects were identified using geometric mean ratios and 90% confidence intervals (CIs) of dose-normalized maximum plasma concentration (C<SUB>max</SUB>) and dose-normalized area under the plasma concentration versus time curve from 0 h to the last measurable concentration (AUC<SUB>0–t</SUB>).</P><P><B>Results</B></P><P>After single-dose administration of eletriptan HBr to Korean subjects, the mean C<SUB>max</SUB> and AUC<SUB>0–t</SUB> increased linearly with dose. Comparable total systemic exposures were observed in the 2 h apart 40 mg repeated and single 80 mg dose. The geometric mean ratios (90% CIs) of the dose-normalized C<SUB>max</SUB> and AUC<SUB>0–t</SUB> of Korean subjects were similar to those of non-Korean subjects reported in the literature. The adverse events observed were transient and mild in severity.</P><P><B>Conclusion</B></P><P>Eletriptan HBr showed linear PK and was well tolerated in Korean subjects. The PK and tolerability of eletriptan HBr did not differ between Korean and non-Korean subjects.</P>

Population Pharmacokinetic Study of Prophylactic Fluconazole in Preterm Infants for Prevention of Invasive Candidiasis

Kim, Yu Kyong,Lee, Juyoung,Oh, Jaeseong,Rhee, Su-jin,Shin, Seung Han,Yoon, Seo Hyun,Lee, SeungHwan,Kim, Han-Suk,Yu, Kyung-Sang American Society for Microbiology 2019 Antimicrobial Agents and Chemotherapy Vol.63 No.6

<P>Fluconazole is an antifungal agent with reported evidence for its prophylactic effect against systemic fungal infection in preterm infants. The aim of this study was to build a population pharmacokinetic model to evaluate the pharmacokinetic characteristics of intravenous and oral fluconazole in preterm infants with the current prophylactic fluconazole dosing regimen.</P><P>Fluconazole is an antifungal agent with reported evidence for its prophylactic effect against systemic fungal infection in preterm infants. The aim of this study was to build a population pharmacokinetic model to evaluate the pharmacokinetic characteristics of intravenous and oral fluconazole in preterm infants with the current prophylactic fluconazole dosing regimen. A pharmacokinetic model was developed using 301 fluconazole concentrations from 75 preterm infants with a baseline body weight (WT) ranging from 0.5 to 1.5 kg and an estimated glomerular filtration rate (eGFR) ranging from 12.9 to 58.5 ml/min/1.73 m<SUP>2</SUP>. Eligible infants received an intravenous or oral dose of 3 mg/kg of body weight of fluconazole, twice weekly with a ≥72-h dose interval, for 4 weeks. The model was qualified with basic goodness-of-fit diagnostics, visual predictive checks, and bootstrapping. The fluconazole pharmacokinetics was well described with a one-compartment linear model with a proportional residual error. The population clearance (CL) and volume of distribution (<I>V</I>) were derived as 0.0197 × (WT/1.00)<SUP>0.746</SUP> × (eGFR/25.0)<SUP>0.463</SUP> × exp(η) and 1.04 × WT × exp(η), respectively. Such covariate analyses augment the awareness of the need for personalized dosing in preterm infants. (This study has been registered at ClinicalTrials.gov under identifier NCT01683760.)</P>

강화학습을 활용한 로봇의 분말 그립 학습

유승환(Seunghwan Yu),홍윤기(Yoonki Hong),정범수(Bumsoo Jeong),임준희(Joonhee Lim),윤종완(Jongwan Yoon),고병진(Byungjin Ko),박태준(Taejoon Park) 한국정보기술학회 2021 Proceedings of KIIT Conference Vol.2021 No.11

본문에서는 강화학습을 활용한 로봇 머니퓰레이터의 분말 그립 자세의 학습을 제안한다. 그리드 좌표로 분말을 그립하는 방법과 비교했을 때, 본문의 방법은 분말소분의 작업을 강력하게 해결할 수 있고, 이는 분말 그립의 성공률을 9.61%향상시킨다. 이 결과는 본문의 방법이 로봇과 강화학습을 사용한 분말소분 공정의 자동화에 유망한 후보임을 보여준다. We present the method of robot manipulator’s powder gripping using reinforcement learning. Compared to a method of gripping the powder with grid coordinates, our method robustly solves the task of powder subdividing, and it improves the success rate of the powder grip by 9.61%. These results show that our method is promising candidate for the automation of the powder subdividing using robot and reinforcement learning.

Structure‐Properties Relationship in Iron Oxide‐Reduced Graphene Oxide Nanostructures for Li‐Ion Batteries

Yu, Seung‐,Ho,Conte, Donato E.,Baek, Seunghwan,Lee, Dong‐,Chan,Park, Seung‐,Keun,Lee, Kyung Jae,Piao, Yuanzhe,Sung, Yung‐,Eun,Pinna, Nicola WILEY‐VCH Verlag 2013 Advanced functional materials Vol.23 No.35

<P><B>Abstract</B></P><P>Non‐aqueous sol‐gel routes involving the reaction of metal oxide precursors in organic solvents (e.g., benzyl alcohol) at moderate temperature and pressure, offer advantages such as high purity, high reproducibility and the ability to control the crystal growth without the need of using additional ligands. In this paper, a study carried out on a series of iron oxide/reduced graphene oxide composites is presented to elucidate a structure‐properties relationship leading to an improved electrochemical performance of such composites. Moreover, it is demonstrated that the easy production of the composites in a variety of temperature and composition ranges, allows a fine control over the final particles size, density and distribution. The materials obtained are remarkable in terms of the particle's size homogeneity and dispersion onto the reduced graphene oxide surface. Moreover, the synthesis method used to obtain the graphene oxide clearly affects the performances of the final composites through the control of the restacking of the reduced graphene oxide sheets. It is shown that a homogeneous and less defective reduced graphene oxide enables good electrochemical performances even at high current densities (over 500 mAh/g delivered at current densities as high as 1600 mA/g). The electrochemical properties of improved samples reach the best compromise between specific capacity, rate capability and cycle stability reported so far.</P>