Earticle

This study presents a comprehensive procedure for the low cycle fatigue test of ultrasonically welded (UW) coated conductor (CC) lap-joints. The entire process is examined in detail, from the robust fabrication of the UW REBCO CC joints to the reliability testing under a low number of repeated cycle fatigue conditions. A continuous Ic measurement system enables real-time monitoring of Ic variations throughout the fatigue tests. The study aims to provide a step-by-step procedure that involves joint fabrication, electromechanical property (EMP) tests under uniaxial tension for stress level determination, and subsequent low-cycle fatigue tests. The joints are fabricated using a hybrid method that combines UW with adding In-Sn soldering, achieving a flux-free hybrid welding approach (UW-HW flux-free). The selected conditions for the low cycle fatigue tests include a stress ratio of R=0.1 and a frequency of 0.02 Hz. The results reveal some insights into the fatigue behavior, irreversible changes, and cumulative damage in the CC joints.

Ultrasonic testing has a characteristics such as excellent permeability, high-sensitivity to find defect and an almost exact measurement for position. size and direction of inner defect, which differ from other non-destructive testing. In the study, we developed program into optimal testing condition, to distinguish obstacle echo and defect position. This program shows generation and processing of ultrasonic pulse. We compared simulation with ultrasonic test in 45$^\circ$, 60$^\circ$and 70$^\circ$transducer. Test results were in accordance with simulation within 0.1~7.2%.

단클론항체의약품은 그 특이성과 높은 효능성으로 인하여 난치성 암 뿐만 아니라, 감염성질환, 면역질환 치료 에 폭넓게 응용되고 있으며 가파르게 세계 바이오시장을 점유하고 있다. 항체의약품은 다양한 원인에 의해 당사슬패 턴의 변화, 산화, 탈아미드화 같은 단백질 변형으로 품질 및 생물학적 활성에 민감한 영향을 받을 수 있기 때문에, 안정성 확보 및 엄격한 품질 관리가 필수적이다. 특히 제조과정이나 보관·유통 중의 온도, pH 등에 따라 생길 수 있는 항체의약품의 전하변이체는 의약품의 효능 및 안정성 평가를 위한 품질 항목으로써 전주기적으로 관리되어야 한다. 본 연구에서는 가혹조건이 단클론항체의약품의 전하변이체 생성에 미치는 영향을 조사하기 위하여, 기존에 설정된 보 관조건과 다른 온도나 pH 가혹조건에서의 단클론항체의 분해양상 및 물리화학적 변화를 정량적으로 평가하였다. 온 도와 pH를 변화시켜 인위적으로 품질을 저하시킨 검체를 유럽약전에 수재되어 있는 인플릭시맙(Infliximab) 농축액의 전하변이체 분석법인 양이온교환 크로마토그래피(CEX-HPLC)를 사용하여 노출시간의 경과에 따른 전하변이체의 량 을 측정하였다. 그 결과, 온도변화(4~40oC)에 따른 단클론항체의 주피크 및 각 전하변이체(acidic and basic) 피크의 비 율에는 큰 변화가 관찰되지 않았으나, 온도 및 pH를 모두 변화시킨 가혹조건에서는 단클론항체의 주피크의 % peak area 가 가혹처리 시간이 증가함에 따라 현저히 감소하는 경향을 보였으며, 특히, 40oC에서는 4oC 및 25oC에 비하여 전하변 이체 변화가 큰 것으로 확인되었다. 또한 낮은 pH 조건(2-4)이 높은 pH(8-9)에 비해 전하변이체의 비율 변화에 크게 영 향을 미치는 것을 확인하였다. 따라서, 단클론항체의약품의 제조공정 중 pH의 변화에 따른 전하변이체의 평가 및 보관 ·운송 중의 잠재적인 가혹조건 노출에 대한 전하변이체의 변화를 유의하여 모니터링할 것을 제안한다. 이상과 같이 온 도 및 pH 가혹처리에 따른 단클론항체의 전하변이체 변화를 정량적으로 평가함으로써 단클론항체의약품의 안정성 평 가시 고려사항을 제공하였으며, 향후, 단클론항체의약품의 효율적인 품질관리에 참고자료로 활용하기를 기대한다.

Monoclonal antibody (mAb) drugs are widely applied to the treatment of infectious diseases and immune diseases as well as cancer because of their specificity and high efficacy and are rapidly occupying the global biotherapeutics market. The quality and biological activity of mAb drugs can be sensitively affected by charge heterogeneity which is caused by unexpected protein modification including glycosylation, oxidation, and deamidation. In particular, an increase in charge variants of mAb drugs that can occur depending on the manufacturing process, pH, and temperature changes during storage and distribution, can affect the efficacy and stability of drugs. To investigate the effect of stress-test conditions on the charge variants of mAb drugs, we performed a quantitative evaluation of decomposition patterns and physicochemical changes of mAb under harsh temperature or pH conditions. Samples artificially stressed by harsh temperature and pH were measured using CEX-HPLC, which is infliximab concentrated solution–charge variants analysis method in European Pharmacopoeia. As a result, a significant change was not observed in the ratio of the main peak and each charge variants peak according to the temperature change (4~40oC). On the other hand, under severe conditions with both temperature and pH change, the significant decrease of the main % peak area of mAb was accelerated as the stress-test time elapsed, especially at 40°C. In addition, the low pH condition (2-4) significantly affected the change in the ratio of the charge variants compared to the high pH (8-9). Therefore, it is proposed to evaluate charge variants according to pH changes during the manufacturing process of mAb drugs and to monitor changes in charge variants for potentially harsh conditions during storage and transportation. In this study, we demonstrated that charge heterogeneity is highly sensitive to pH-stressed conditions, suggesting that quantitative evaluation of charge variants of mAb during the manufacturing process and storage can provide one of the good indicators for stability. These results also contribute to the efficient quality control during the life-cycle of mAb drugs as reference data.

The purpose of this study was to examine the relationships between the ankle dorsiflexion passive range of motion (DF PROM) under a non-weight bearing condition and the normalized reach distance in three directions of the Y-Balance Test (YBT). Sixty-one healthy adults (32 males and 29 females, age: $23.0{\pm}3.0$ years, height: $169.3{\pm}8.9cm$, weight: $61.9{\pm}5.4kg$) participated in this study. The ankle DF PROM was measured using a goniometer. To assess dynamic balance, all subjects performed three trials to determine the maximum lower extremity reach in the anterior, posteromedial, and posterolateral directions of the YBT. The relationship between the ankle DF PROM and both the normalized reach distance in each direction and the composite score of the YBT were analyzed using the Pearson correlation. Only the normalized reach distance in the anterior direction of the YBT was significantly related to the ankle DF PROM measured under a non-weight bearing condition (r=.50, p<.001). Neither the normalized reach distances in the posterior directions nor the composite score of the YBT were significantly correlated with the ankle DF PROM measured under a non-weight bearing condition. These findings suggest that ankle DF PROM does not affect the overall dynamic balance of the lower extremity, with only the anterior dynamic balance affected among the three directions.

Conversion to modern hydrogen energy is required, and research on liquefied hydrogen cargo containment systems is needed for large-capacity transport and storage. In this study, changes in the mechanical properties of the adhesive required for storage and transport in liquid hydrogen were confirmed. The lap shear test was performed by realizing cryogenic conditions in a small chamber using liquid nitrogen and liquid helium. There was an increase of 11.0% in the -180℃ condition compared to room temperature, and an increase of 1.8% in the -230℃ condition compared to the -180℃ condition was confirmed. In the case of shear strain, it is known that it decreases as the temperature goes down. As a result of the experiment, it was confirmed that the value at room temperature and the value at -180℃ reduced the shear strain by 5.0%, and -230˚ compared to the -180℃ condition. An increase of 1.5% was confirmed in the C condition. In the case of the specimen tested at -230℃, the deformation in the gripper part was larger than in other tests, and it is judged that the maximum shear strength and shear strain were affected. In addition, in this study, there is a limitation in the experiment at -230°C rather than 253°C, which is the boiling point of hydrogen.

Boltwood 구름센서는 구름으로부터 복사되는 적외선을 감지하여 구름의 유무와 많고 적음을 판별할 수 있는 기상센서의 한 종류이 다. 이 구름센서는 한국천문연구원이 진행하고 있는 국가현안과제의 일환인 우주물체 전자광학 감시체계 시스템(OWL, Optical Wide-field patroL)에 사용될 계획이다. 실제 시스템 적용에 앞서, Boltwood 구름센서를 충북대학교 천문대에 설치, 약 2주간 구름센 서의 구름감지 성능 시험을 위한 관측을 진행하였다. 구름센서의 성능과 비교할 대상으로 충북대학교 천문대에 현재 설치, 운영 중인 구름량 측정을 위한 CCD 관측시스템을 이용하였다. 성능 테스트 결과, 하늘과 지상의 온도차이와 측광 자료의 별 개수간 명확한 상관관계가 도출되지 못했다. 그 원인으로는 시험 환경상의 문제와 Boltwood 구름센서의 내부 알고리즘 및 하드웨어에 대한 정보공 개가 제한 때문인 것으로 판단된다. 이 논문에서는 Boltwood 구름센서와 CCD 관측시스템의 구름지수를 비교, 분석한 과정과 그 상세 결과를 제시하고자 한다.

The Boltwood Cloud Sensor is meteorological sensor that is used to estimate an amount of clouds in the sky. This sensor will be installed for OWL(Optical Wide-field patroL) telescope and observatory system of Korea Astronomy and Space Science. Before applying this sensor to an observatory system, we performed test observations at Chungbuk University Observatory at Jincheon, Chungbuk. During the test run, a significant correlation between air temperature difference and the number of visible stars recorded in the CCD frames has not been found. This preliminary result can be attributed to test environment of the observation and our lack of knowledge on calculation algorithm as well as the hardware system of the Boltwood Cloud Sensor.In this paper, we present the procedure and the result of the performance test employing the cloud sensor.

학교 교실은 일반적인 교육 용도로 사용되는 시설로, 다른 청취평가용 공간과는 달리 청취 전용의 설비가 갖추어져 있지 않은 경우가 대부분이다. 대체로 전관방송(화재방송, 시종, 공지사항 전달, 소방 훈련 등)에 쓰기 위한 스피커 유니트가 별다른 기준이나 표준도 없이 교실 중앙 부근 천장에 하나 설치되어 있을 뿐이다. 이 스피커 유니트의 품질이나 재생시스템의 유효성 여부를 차치하고라도 하나의 유니트로 전체 교실의 청취환경을 고르게 유지할 수 있을지 의심하지 않을 수 없다. 스피커와 가까운 자리에 있는 학생들은 충분한 크기의 명료한 소리를 듣지만 먼 쪽에 있는 학생들은 그렇지 못하다면 청취평가의 신뢰성에 큰 문제가 있는 것이다. 이러한 현황에 비추어 기존 교실에 전관방송 목적으로 설치되어진 스피커 유니트가 교실 내 전체적으로 고른 청취환경을 보장할 수 있는 것인지에 대하여, 그리고 청취평가의 신뢰성 확보를 위해 교실 청취환경의 편차를 개선할 수 있는 대안에 대하여 연구하였다.

Listening environment of classrooms is getting more important for the improvement of the efficiency of teaching as multimedia equipments are being used widely. It is also important for students at the age period to develop the language senses as well as the listening test performed in classrooms. Current classroom contains only on loudspeaker unit on ceiling for emergency call and public address. The diversity of listening environments in classrooms may affect on the score of the listening tests in different positions. This study aims at the improvement of uniformity in listening condition at classrooms for the reliability of lustening test concentrated on the quality and arrangement of such loudspeaker units

Environmental pollution has led to global warming, which threatens human life. In response, hydrogen is gaining attention as a next-generation energy source that does not emit carbon. Due to its explosive nature, special care must be taken in the safe storage and transportation of hydrogen. Among various storage methods, liquefied storage, which can reduce its volume to 1/800, is considered efficient. However, since its boiling point reaches -253°C, the design of an insulation system is essential. For the design of insulation systems applied to large containers, a membrane-type design is required, which necessitates the use of cryogenic adhesives. To evaluate whether the cryogenic adhesive is properly implemented, assessments such as tensile and shear tests are necessary. This study presents a methodology for shear evaluation. Conventional methods for shear evaluation of adhesives result in slippage, preventing proper assessment. Therefore, a method involving drilling holes in the gripper and pulling from the holes must be applied. Optimal design concerning the size and location of the holes is required, and this study derives optimal values based on finite element analysis. By conducting experiments based on the results of this study, it is expected that the risk of gripper damage will be minimized, allowing for accurate evaluation of the adhesive’s performance.

As the capacity of renewable power generation facilities rapidly increases, the variability of electric power system and gas turbine power generation is also increasing. Therefore, problems may occur that require urgent repair while the gas turbine rotor is stopped. When the gas turbine rotor turning is stopped and then restarted, if the turning period is not appropriate, severe vibration may occur due to rotor bending. As a result of the experiment, it was confirmed that normal operation is possible when the gap data measured at the start of rotor turning after maintenance work is similar to the existing value. And the vibration value at the start of rotor turning was lower as the rotor temperature was lower or the stop period was shorter.

IAEA 및 국내의 방사성물질 운반 관련 규정에 따라 중·저준위 방사성폐기물 드럼 8개를 운반할 수 있는 IP-2형 운반용기를 개발하였다. IP-2형 운반용기는 낙하시험 및 적층시험을 거친 후 내용물의 유실 또 는 분산과 운반용기 외부표면에서의 방사선량률이 20 % 이상 증가할 수 있는 차폐능력의 상실이 없어야 한다. 본 연구의 목적은 적층시험조건에 대한 시험방법 및 절차를 수립하고 IP-2형 운반용기의 적층조건 에 대한 구조적 건전성을 평가하는데 있다. 운반용기의 원형시험모델을 이용하여 운반용기 중량의 5배 하중으로 24시간 동안 압축하는 적층조건에 대한 시험 및 전산해석을 수행하였다. 적층시험 시 운반용기 의 모서리기둥에서의 변형률 및 변위를 측정하였으며, 측정된 변형률 및 변위는 해석결과와 서로 일치하 였다. 컨테이너 바닥부의 처짐량은 측정이 어렵기 때문에 전산해석 방법으로 구하였다. 모서리기둥의 최 대 변위와 컨테이너 바닥의 최대 처짐은 법규에서 규정하는 허용치에 비하여 낮게 나타났다. 적층시험 전?후에는 운반용기의 외형치수, 차폐체 두께, 볼트토크 등을 측정하였으며, 그 값들을 비교분석한 결과 운반용기는 내용물의 유실 및 분산, 차폐체 두께의 감소가 나타나지 않았다. 따라서 적층시험조건에서 IP-2형 운반용기의 구조적 건전성이 입증되었다.

Radioactive waste transport package was developed to transport eight drums of low and intermediate level waste(LILW) in accordance with the IAEA and domestic related regulations. The package is classified with industrial package IP-2. IP-2 package is required to undergo a free drop test and a stacking test. After free drop and stacking tests, it should prevent the loss or dispersal of radioactive contents, and loss of shielding integrity which would result in more than 20 % increase in the radiation level at any external surface of the package. The objective of this study is to establish the safety test method and procedure for stacking test and to prove the structural integrities of the IP-2 package. Stacking test and analysis were performed with a compressive load equal to five times the weight of the package for a period of 24 hours using a full scale model. Strains and displacements were measured at the corner fitting of the package during the stacking test. The measured strains and displacements were compared with the analysis results, and there were good agreements. It is very difficult to measure the deflection at the container base, so the maximum deflection of the container base was calculated by the analysis method. The maximum displacement at the corner fitting and deflection at the container base were less than their allowable values. Dimensions of the test model, thickness of shielding material and bolt torque were measured before and after the stacking test. Throughout the stacking test, it was found that there were no loss or dispersal of radioactive contents and no loss of shielding integrity. Thus, the package was shown to comply with the requirements to maintain structural integrity under the stacking condition.

Testing is very expensive for high-assurance software, like commercial aircraft systems, weapon research, weather forecast, earthquake forecast, and software used for safety critical system. A small and simple flaw in the end product can be enough for destroying the entire effort of the developer with a huge unrecoverable damage to the society. For this reason, Federal Aviation Administration’s requirement is that, the test-suites should be comprises of Modified Condition/Decision Coverage (MC/DC) adequate. By using logic coverage criteria lots of flaws can be removed for safety critical software. MC/DC was proposed by NASA, and had been widely accepted in the field of testing. MC/DC is an effective verification technique, and helps to uncover safety faults. It is a challenge to minimize the number of test-suites when there is a partial change in the software. This can be achieved by using models. Unified Modeling Language (UML) not only helps to design software but also plays a vital role in detecting the faults early phase of design and in minimizing the test-suite. Existing test-suite minimization techniques investigated by different researchers may not be effective in minimizing MC/DC-adequate test-suites because they do not consider the complexity of the present software. A new approach for test-suite minimization is presented in this work, using dissimilarity matrix, which can be well fitted with MC/DC. We also present the results generated out of a case study of the test-suite minimization.

최근 도심지 주변으로 집중되는 신축구조물 및 공동구 확장 등과 같은 인접굴착공사로 인해 운영중인 철도 구 조물의 변형이 발생되고 있다. 그러나 대부분 구조물에 대한 구조검토 및 보수보강에 집중되고 있으며 궤도에 대한 검토는 부족한 실정이다. 특히 토공노반 상 자갈궤도의 경우 노반과 도상자갈이 강결된 구조가 아니므로, 미소한 수 준의 변형으로도 도상자갈 이완현상이 발생할 수 있다. 이는 침목 지지조건이 불안정한 조건으로 유도될 수 있으므로 충분한 안전성을 확보해야한다. 또한 불안정한 지지조건으로 열차탈선의 위험이 매우 높은 궤도형식이다. 따라서 본 연구에서는 노반 변형에 따른 자갈궤도의 변형특성과 궤도지지성능의 상관관계를 실험 및 해석적으로 입증하고, 자갈 궤도의 상태 및 궤도지지강성을 평가할 수 있는 평가기법을 제시하고자 한다.

Recently, deformation of operating railway structures has occurred due to adjacent excavation works such as new structures and utility tunnel expansion concentrated around downtown areas. However, most of them are focused on structural review, repair and reinforcement of structures. A review of the Track is insufficient. In particular, in the case of the gravel track on the earthwork subgrade, the subgrade and the ballast are not solidified. A slight level of deformation can cause ballast relaxation. Sleeper support conditions may lead to unstable conditions. Sufficient safety must be ensured. In addition, it is a track type with a high risk of train derailment due to unstable support conditions. In this study, the correlation between the deformation characteristics of gravel tracks and track support performance according to subgrade deformation is experimentally and analytically verified. In addition, an evaluation technique that can evaluate the condition of the gravel track and the track support stiffness is presented.

This study was conducted to find out the improvement of skin hydration, persistency, transepidermal water loss (TEWL) and itchy of moisturizing cream. The moisturizing cream is containing vernix caseosa mimetic (VCM), Actium lappa seed extract in liquid crystal system. In previous study, We developed vernix caseosa analogues mimicking the unique structure and properties of natural vernix caseosa. Actium lappa seed extract has the effect on lipid synthesis on human keratinocyte. We have investigated whether topical application of moisturizing cream and placebo cream improve the skin hydration, persistency, TEWL and itchy. The number of study participants were 40, including 20 study group (Group B) and 20 control group (Group A). The subjects in study group applied moisturizing cream containing VCM, arctium lappa seed extract in liquid crystal system on face (cheek) and thigh twice a day for 4weeks. The ones in control group applied cream without active ingredients in same methods. The hydration persistency test was conducted with 20 male and female on forearm. Our results showed that moisturizing cream (Group B) improved the skin hydration on cheek and thigh after 2weeks and 4weeks compared with before application. While the control group (Group A) was not showed the skin hydration effect compared with before application. Moisturizing cream (Group B) improve the decreasing TEWL on cheek and thigh after 2weeks and 4weeks compared with before application. But the control group (Group A) improved the decreasing TEWL on cheek after 2weeks and 4weeks compared with before application. Moisturizing cream (Group B) showed high moisturizing value and long holding time of hydration. In this study, we evaluated decreasing itch of moisturizing cream (Group B) and control cream (Group A) by assessment questionnaire. Moisturizing cream (Group B) improve the itch after 2weeks and 4weeks compared with before application. These studies show that moisturizing cream containing VCM and arctium lappa seed extract in liquid crystal system can improve skin hydration, persistency, TEWL and itch in the dry skin.

$\textbullet$ Contents 1 Abstract $\textbullet$ Contents 2 Introduction $\textbullet$ Contents 3 Design of the system $\textbullet$ Contents 4 Creating product database $\textbullet$ Contents 5 Functionality testing $\textbullet$ Contents 6 Conclusion $\textbullet$ Contents 7 References

In this study, it was studies the utilization of LIT(lock-in infrared thermography) which can detect defects in welded parts of ship and offshore structures. Quantitative analysis was used through methods of filtering and texture measurement of image processing techniques to find the optimized experimental condition. We verified reliability in our methods by applying image processing techniques in order to normalize evaluations of comparative images that show phase difference. In addition, low to mid exposure showed good results whereas high exposure did not provide significant results in regards to intensity of light exposure on surface. Lock-in frequency was satisfactory around 0.1 Hz regardless of intensity of light source we had. In addition, having the integration time of thermography camera inversely proportional to intensity of exposed light source during the experiment allowed good outcome of results.

Carbon/carbon composites are ideal candidates for a number of aerospace applications including structural materials for advanced vehicles, leading edges, structures of re-entry and hypersonic vehicles and propulsion systems. One serious defect for such application of the carbon/carbon composites is their poor oxidation resistance in high temperature oxidizing environments. SiC coating was employed to protect the composites from oxidation. It is mechanically and chemically stable under extreme thermal and oxidative environments, provides good adhesion to the substrate, and offers good thermal shock resistance. The SiC layer on the nozzle machined from the carbon/carbon composites was formed by pack-cementation method. Then, erosion characteristic of SiC coated carbon/carbon nozzle was examined by combustion test using a liquid rocket motor. The erosion rates were measured as function of combustion pressure, ratio of oxygen to fuel, combustion time, density of the composites and geometry of reinforced carbon fibre in the composites. The morphology change of the composites after combustion test was investigated using SEM and erosion mechanism also was discussed.