• 한국의류산업학회지
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• 제22권5호
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• pp.686-695
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• 2020

The present study evaluated the manual dexterity and usability of conductive gloves when operating touchscreen devices in the cold. Twelve male subjects (23.3±1.5 years in age) participated in three experimental conditions: no gloves, fabric conductive and lambskin conductive gloves. Manual dexterity was tested using both Purdue Pegboard (PP) and ASTM dexterity tests at an air temperature of 5℃ and air humidity of 30%RH. Glove usability was tested through the following touchscreen tests: tap, double tap, long tab, drag, flick, and multi-touch. The results showed that manual dexterity according to the PP (2.5 mm of a pin diameter) and ASTM tests (8 mm of a stick diameter) was worse for the two glove conditions than for the no glove condition (p<.005). PP dexterity was better for the fabric glove condition than for the lambskin glove condition (p<.05); however, there was no difference in ASTM dexterity between the two glove conditions. Hand and finger skin temperatures were higher for the glove conditions than the bare hand condition (p<.05), with no differences between the two glove conditions. The touchscreen usability was the best for the no glove condition, followed by fabric gloves (p<.05). Wearing either fabric or lambskin gloves diminishes hand dexterity while maintaining hand and finger temperatures at higher levels. For improved hand dexterity in dealing with small numbers, letters on a touchscreen in cold environments, we recommend wearing fabric conductive gloves rather than lambskin conductive gloves.

• Tribology and Lubricants
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• 제36권3호
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• pp.124-132
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• 2020

The effect of the stoichiometry on the sliding wear properties of NiAl coatings has been investigated. Three different powder mixtures with the compositions of Ni-50at%Al, Ni-54at%Al and Ni-42at%Al were diepressed respectively, and which were subsequently coated on mild steel through combustion synthesis in an induction heating system. Sliding wear behavior of the coatings was examined against an alloyed tool steel using a pin-on-disc type sliding wear test machine. As results, it could be seen that powder mixture(Ni-54at%Al) with displaying Al-rich deviations from the stoichiometry of NiAl(Ni-50at%Al) was promoted the most the synthetic reactivity. The microstructure of the coating layer with the compositions of Ni-54at%Al exhibits the porous NiAl single phase structure. However, the microstructure of the coating layer of the compositions of Ni-42at%Al exhibits the denser multi-phase structure containing several intermediate phases in addition to NiAl. Densification of the coating layer was enhanced by increasing the reacting temperature. On the other hand, the wear properties of the coating layers showed that the wear mode at speeds of around 1 m/s was severe wear, regardless of the stoichiometry and reacting temperature. However, wear properties of coating layer with the compositions of Ni-42at%Al were superior to those of coating layer with the compositions of Ni-54at%Al. This would be attributed by the fact that coating layer with the compositions of Ni-42at%Al develops little void and much intermediate phases with high strength.

• Steel and Composite Structures
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• 제29권1호
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• pp.1-22
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• 2018

Multi-storey precast concrete skeletal structures are assembled from individual prefabricated components which are erected on-site using various types of connections. In the current design of these structures, beam-to-column connections are assumed to be pin jointed. Welded plate beam to-column connections have been used in the precast concrete industry for many years. They have many advantages over other jointing methods in component production, quality control, transportation and assembly. However, there is at present limited information concerning their detailed structural behaviour under bending and shear loadings. The experimental work has involved the determination of moment-rotation relationships for semi-rigid precast concrete connections in full scale connection tests. The study reported in this paper was undertaken to clarify the behaviour of such connections under symmetrical vertical loadings. A series of full-scale tests was performed on sample column for which the column geometry and weld arrangements conformed with successful commercial practice. Proprietary hollow core slabs were tied to the beams by tensile reinforcing bars, which also provide the in-plane continuity across the connections. The strength of the connections in the double sided tests was at least 0.84 times the predicted moment of resistance of the composite beam and slab. The secant stiffness of the connections ranged from 0.7 to 3.9 times the flexural stiffness of the attached beam. When the connections were tested without the floor slabs and tie steel, the reduced strength and stiffness were approximately a third and half respectively. This remarkable contribution of the floor strength and stiffness to the flexural capacity of the joint is currently neglected in the design process for precast concrete frames. In general, the double sided connections were found to be more suited to a semi-rigid design approach than the single sided ones. The behaviour of double sided welded plate connection test results are presented in this paper. The behaviour of single sided welded plate connection test results is the subject of another paper.

• Journal of Radiation Protection and Research
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• 제42권2호
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• pp.91-97
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• 2017

Background: A gamma energy identifying algorithm using spectral decomposition combined with smoothing method was suggested to confirm the existence of the artificial radio isotopes. The algorithm is composed by original pattern recognition method and smoothing method to enhance the performance to identify gamma energy of radiation sensors that have low energy resolution. Materials and Methods: The gamma energy identifying algorithm for the compact radiation sensor is a three-step of refinement process. Firstly, the magnitude set is calculated by the original spectral decomposition. Secondly, the magnitude of modeling error in the magnitude set is reduced by the smoothing method. Thirdly, the expected gamma energy is finally decided based on the enhanced magnitude set as a result of the spectral decomposition with the smoothing method. The algorithm was optimized for the designed radiation sensor composed of a CsI (Tl) scintillator and a silicon pin diode. Results and Discussion: The two performance parameters used to estimate the algorithm are the accuracy of expected gamma energy and the number of repeated calculations. The original gamma energy was accurately identified with the single energy of gamma radiation by adapting this modeling error reduction method. Also the average error decreased by half with the multi energies of gamma radiation in comparison to the original spectral decomposition. In addition, the number of repeated calculations also decreased by half even in low fluence conditions under $10^4$ ($/0.09cm^2$ of the scintillator surface). Conclusion: Through the development of this algorithm, we have confirmed the possibility of developing a product that can identify artificial radionuclides nearby using inexpensive radiation sensors that are easy to use by the public. Therefore, it can contribute to reduce the anxiety of the public exposure by determining the presence of artificial radionuclides in the vicinity.

• 한국의학물리학회지:의학물리
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• 제13권4호
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• pp.218-223
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• 2002

두개외 병소 즉, 척추 등에 발생한 종양 혹은 혈관기형 등의 병소에 대해 침습적 수술이 불가한 경우 정위적 방사선 수술이 임상에서 시도되고 있다. 본 연구는 실험적으로 팬텀에 대해 척추 정위 방사선수술을 시행하고 결과 분석을 통하여 두개외 수술 목표점에 대한 방사선수술 위치 정확도를 평가하고자 한다. 이 실험을 위하여 팬텀을 특별히 고안하였으며 수술실에서 방사선 수술 목표점의 위치는 광학적 추적 장치를 이용하여 결정하였고 3 mm 미세다엽시준기(mMLC; mcro Multi-Leaf Collimator)를 사용하여 시술하였다. 팬텀의 목표점에 대한 방사선수술 오차는 $\pm$1 mm 이내였으며 분할방사선 수술 경우도 $\pm$1 mm 이내였다. 결과적으로 광학적 위치추적 장치를 이용한 두개외 목표점의 방사선 수술은 매우 정확하고 유용한 방법으로 판단된다.

• 방사성폐기물학회지
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• 제12권1호
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• pp.79-88
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• 2014

원자력이용시설에서 발생한 작은 크기의 금속 조각들을 효과적으로 제염하는 스마트 장치를 개발하였다. 이 장치는 자성연마재를 포함한 영역의 자속밀도를 연속적으로 변화시키는 방법과 초음파를 이용하는 다중 제염장치이다. 한편, 제염 효율을 높이기 위해 제염 장치가 제염 대상 전체에 작용하도록 장치들의 구성을 수정하였다. 개발된 장치들의 최적 작동조건을 도출하여 샘플로 선정한 소형의 금속방사성페기물에 대하여 자기장과 초음파제염을 각각 15분간 실시하였다. 그 결과 제염계수의 범위는18~56으로 크게 향상되었으며 제염 후 모든 샘플은 백그라운드(BKG)값 이하로 확인되었다.

• 한국기계가공학회지
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• 제12권6호
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• pp.152-158
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• 2013

The purpose of this study is to investigate cooling performance of high power LEDs from 100 to 200 W class by using a jet impingement cooling module. The numerical analysis of forced convection cooling inside cooling module is carried out using a multi-purpose CFD software, FLUENT 6.3. In the experiments, the LED cooling system consists of jet impingement module, heat exchanger, water reservoir, and pump. In the present study, the cooling performance of jet impingement cooling module is investigated to determine the effect of the heat sink types on the impinging surface, the space and length of fins. Numerical and experimental studies show the reasonable agreement of LED metal PCB temperature between those results and give the optimized design parameters such as the space of fin and the length of fin. Also, the pin fin type of heat sink is found to be more efficient than the plate type heat sink in jet impingement cooling.

• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1563-1570
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• 2023

In this study, a DeCART/MIG uncertainty quantification (UQ) analysis code system with a multicorrelated cross section stochastic sampling (S.S.) module was established and verified through the UAM (Uncertainty Analysis in Modeling) and the BEAVRS (Benchmark for Evaluation And Validation of Reactor Simulations) benchmark calculations. For the S.S. calculations, a sample of 500 DeCART multigroup cross section sets for two major actinides, i.e., ²³⁵U and ²³⁸U, were generated by the MIG code and covariance data from the ENDF/B-VII.1 evaluated nuclear data library. In the three pin problems (i.e. TMI-1, PB2, and Koz-6) from the UAM benchmark, the uncertainties in k_inf by the DeCART/MIG S.S. calculations agreed very well with the sensitivity and uncertainty (S/U) perturbation results by DeCART/MUSAD and the S/U direct subtraction (S/U-DS) results by the DeCART/MIG. From these results, it was concluded that the multi-group cross section sampling module of the MIG code works correctly and accurately. In the BEAVRS whole benchmark problems, the uncertainties in the control rod bank worth, isothermal temperature coefficient, power distribution, and critical boron concentration due to cross section uncertainties were calculated by the DeCART/MIG code system. Overall, the uncertainties in these design parameters were less than the general design review criteria of a typical pressurized water reactor start-up case. This newly-developed DeCART/MIG UQ analysis code system by the S.S. method can be widely utilized as uncertainty analysis and margin estimation tools for developing and designing new advanced nuclear reactors.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3732-3753
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• 2023

The Real-time Analysis for Particle-transport and In-situ Detection (RAPID) Code System, developed based on the Multi-stage Response-function Transport (MRT) methodology, enables real-time simulation of nuclear systems such as reactor cores, spent nuclear fuel pools and casks, and sub-critical facilities. This paper presents the application of a novel fission matrix-based burnup methodology to the well-characterized JSI TRIGA Mark II research reactor. This methodology allows for calculation of nuclear fuel depletion by combination and interpolation of RAPID's burnup dependent fission matrix (FM) coefficients to take into account core changes due to burnup. The methodology is compared to experimentally validated Serpent-2 Monte Carlo depletion calculations. The results show that the burnup methodology for RAPID (bRAPID) implemented into RAPID is capable of accurately calculating the k_eff burnup changes of the reactor core as the average discrepancies throughout the whole burnup interval are 37 pcm. Furthermore, capability of accurately describing 3D fission source distribution changes with burnup is demonstrated by having less than 1% relative discrepancies compared to Serpent-2. Good agreement is observed for axially and pin-wise dependent fuel burnup and nuclear fuel nuclide composition as a function of burnup. It is demonstrated that bRAPID accurately describes burnup in areas with high gradients of neutron flux (e.g. vicinity of control rods). Observed discrepancies for some isotopes are explained by analyzing the neutron spectrum. This paper presents a powerful depletion calculation tool that is capable of characterization of spent nuclear fuel on the fly while the reactor is in operation.

• 정보처리학회논문지B
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• 제9B권2호
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• pp.245-254
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• 2002

머신비전을 이용한 IC 패키지 마킹검사 시스템은 입력영상으로부터 검사할 요소들의 위치를 식별하고, 추출된 요소들을 학습된 표준 패턴과 비교하여 마킹의 불량 여부를 판단한다. 본 논문에서는 검사 대상 IC 패키지의 위치 판별, 마킹문자 추출, 핀원딤플 검출과 같은 일련의 작업들에 적합한 적응적 다단계 이진화 방법과 마킹문자의 국소적인 오류검출은 물론 잡영에 강건한 정합단위의 동적 선택 방법을 제안한다. 제안하는 이진화 방법은 이진화 대상 영역과 명도 값의 범위를 제한하여 Otsu의 이진화 알고리즘을 적용함으로써 특정 응용에 적응적인 이진화가 가능하다. 정합단위의 동적 선택 방법은 문자추출 및 배치분석에 대한 결과에 따라 정합단위를 선택한다. 그러므로 문자추출 및 배치분석 과정에서 발생하는 예기치 못한 부적절한 상황에서도 가능한 범위내에서 최소의 정합단위를 선택할 수 있다. 제안된 방법을 구현하여 8종의 IC 패키지, 총 280개의 영상에 대하여 실험한 결과, IC 패키지와 핀원딤플의 검출율은 100%였으며, 마킹상태에 대한 판정은 98.8%의 정확도를 나타내어 제안된 방법이 효과적임을 확인할 수 있었다.