Laser cutting has been recognized as one of key techniques in dismantling nuclear power plants as it has several advantages such as a remote operation and a reduced secondary waste. However, it generates a significant amount of aerosols that can pose a health risk to workers and further induce environmental pollution during the cutting operation. Thus, understanding the aerosol characteristics generated by the laser cutting is crucial for implementing an effective cutting operation and reducing the exposure to these hazardous particles. In this work, we established a methodology to collect the aerosols and investigate their properties in the laser cutting operation. We built an integrated laser cutting system for aerosol analyses, consisting of a high-power laser cutting module, a metal sample holder, an aerosol collector, and a closed chamber. We expect that this system will offer an opportunity for in-depth understanding of the aerosol properties, by connecting it with desired type of aerosol analysis platforms, and further safe dismantling operation of the nuclear power plants.

During the decommissioning of a nuclear power plant, the structures must be dismantled to a disposal size. Thermal cutting methods are used to reduce metal structures to a disposal size. When metal is cut using thermal cutting methods, aerosols of 1 μm or less are generated. To protect workers from aerosols in the work environment during cutting, it is necessary to understand the characteristics of the aerosols generated during the cutting process. In this study, changes in aerosol characteristics in the working environment were observed during metal thermal cutting. The cutting was done using the plasma arc cutting method. To simulate the aerosols generated during metal cutting in the decommissioning of a nuclear power plant, a non-radioactive stainless steel plate with a thickness of 20 mm was cut. The cutting condition was set to plasma current: 80 A cutting speed: 100 mm/min. The aerosols generated during cutting were measured using a highresolution aerosol measurement device called HR-ELPI+ (Dekati®). The HR-ELPI+ is an instrument that can measure the range of aerodynamic diameter from 0.006 μm to 10 μm divided into 500 channels. Using the HR-ELPI+, the number concentration of aerosols generated during the cutting process was measured in real-time. We measured the aerosols generated during cutting at regular intervals from the beginning of cutting. The analyzed aerosol concentration increased almost 10 times, from 5.22×106 [1/cm3] at the start of cutting to 6.03×107 [1/cm3] at the end. To investigate the characteristics of the distribution, we calculated the Count Median Aerodynamic Diameter (CMAD), which showed that the overall diameter of the aerosol increased from 0.0848 μm at the start of cutting to 0.1247 μm at the end of the cutting. The calculation results were compared with the concentration by diameter over time. During the cutting process, particles with a diameter of 0.06 μm or smaller were continuously measured. In comparison, particles with a diameter of 0.2 μm or larger were found to increase in concentration after a certain time following the start of cutting. In addition, when the aerosol was measured after the cutting process had ended, particles with a diameter of 0.06 μm or less, which were measured during cutting, were hardly detected. These results show that the nucleation-sized aerosols are generated during the cutting process, which can explain the measurement of small particles at the beginning of cutting. In addition, it can be speculated that the generated aerosols undergo a process of growth by contact with the atmosphere. This study presents the results of real-time aerosol analysis during the plasma arc cutting of stainless steel. This study shows the generation of nucleation-sized particles at the beginning of the cutting process and the subsequent increase in the aerosol particle size over time at the worksite. The analysis results can characterize the size of aerosol particles that workers may inhale during the dismantling of nuclear power plants.

Recently, halogen lamps for vehicle exterior lamp systems are being replaced by LEDs (Light Emitting Diode) in consideration of miniaturization, power consumption, life, luminance, and eco-friendliness. Due to regulations on the amount of light required, luminance, light uniformity, and glare prevention, it is required to develop a light guide for controlling a light source of an LED lamp for a vehicle. For the development of the light guides, the development of machining technology that can cut micro patterns of hundreds of micrometers scale into surface roughness of tens of nanometers scale must be preceded. In this study, the effect of variations in cutting conditions on surface roughness was analyzed through experiments. The micro patterns was manufactured by cutting into STAVAX material, and the surface of the micro patterns was super-finished using a ball-shaped PCD (polycrystalline diamond) tool without flutes. In experiments, the cutting conditions of the super-finishing process were varied, and the varied cutting conditions were feed rate, radial depth of cut, and spindle speed

The purpose of using coolant in machining is both to increase a tool life and also to prevent product deformation and thus, stabilize the surface quality by lubricating and cooling the tool and the machining surface. However, a very small amount of cutting mist should be used because chlorine-based extreme pressure additives are used to generate environmental pollutants in the production process and cause occupational diseases of workers. In this study, medical titanium alloy (Ti-6Al-7Nb) was subjected to a processing experiment by selecting factors and levels affecting cutting power in the processing of the Aerosol Dry Lubrication (ADL) method using vegetable oil. The machining shape was a slot to sufficiently reflect the effect of the cutting depth. As for the measurement of cutting force, the trend of cutting characteristics was identified through complete factor analysis. The factors affecting the cutting force of ADL slot processing were identified using the reaction surface analysis method, and the characteristics of the cutting force according to the change in factor level were analyzed. As the cutting speed increased, the cutting force decreased and then increased again. The cutting force continued to increase as the feed speed increased. The increase in the cutting depth increased the cutting force more significantly than the increase in the cutting speed and the feed speed. Through the reaction surface analysis method, the regression equation for predicting cutting force was identified, and the optimal processing conditions were proposed. The cutting force was predicted from the secondary regression equation and compared with the experimental value.

진정한 의미에서의 민간예술작품에서 구현하는 것은 겉면에 표출된 화려한 표상할 뿐만 아니라 그 내면을 탐구하는 것, 더욱 이런 예술 풍격을 단조해 낸 불굴의 민족의식과 정감이다. 예로부터 사회의 발전과 계급 분화로 원시 예술의 변천을 거쳐 분리되어 형성된 문인예술, 궁정예술, 종교예술, 민간예술에 이르기까지 이러한 다른 관념을 기반으로 한 예술 문화 종류가 역사의 흐름 속에서 갈등하고 또 끊임없이 서로 연계하며 기반으로 하고 모순, 연계와 융합에서 하나의 완전한 민족 문화를 육성하였다. 오늘에 이르기까지 민간예술문화에서의 순수한 예술 신념은 여전히 줄곧 이른바 고상하고 우아한 예술 문화에 대해 확고한 기초적 역할을 하고있다. 수암만족 민간 전지(剪紙)는 동북 백산흑수사이에 만족 노동 인민이 창조한 역사적 예술 문화의 완벽한 결정체일 뿐만아니라 또한 수암의 전통적 만족 민간 예술 특유한 민족 예술문화 표식이고 동북 지역의 만족 의향 및 옥도 특색의 전통 민간예술의 걸출한 대표이다. 이것은 동북 만족 인민의 지혜의 예술을 포함하고 있으며 중요한 역사적 가치와 문화적 가치가 있을 뿐만 아니라 또한 중요한 예술적 가치와 과학적 가치를 지니고 있으며 전통문화의 결정체이자 화하문명의 보물이다. 지금은 어떤 의미에서 이미 문화브랜드로 된 민간 전지예술이 점차 문화의 수요품으로 되고 있다. 특유의 가치와 방식으로 문화가 널리 전파되는 또 다른 경로로 되고 있다. 그러나 북방 만족 전지를 놓고 말할 때 기나긴 과정에서 아주 많은 문제도 나타났다. 이를테면 제작 형식과 예술 풍격의 혼동, 관련 문화자료내용의 귀납 정리와 발전 전승 등이다. 본 논문은 북방 만족 문화의 대표 특징을 지닌 수암만족 전지를 연구 대상으로 지역 역사, 문화 신앙 등등 방면에 대해 중국 북방 만족 종이 오림이 형성된 근원성 원인을 심도 있게 분석하였다. 이와 동시에 종이 오림 작품이 드러낸 예술 상태에 있어서 다른 지역의 동류 작품들과 전체적 및 개별적 비교를 하여 예술풍격상의 지역문화 차이를 분명히했다. 또 현재를 결부시켜 전지 예술이 사람들에게 대한 의의를 서술하고 전통문화를 발전시키고 전승할 것을 호소했다.

절화장미 삽목묘 대량생산 효율을 높이기 위해 국내 육성 절화장미 ‘엔틱컬’(Rosa hybrida ‘Antique Curl’)을 대상으로 생장 활력이 높은 단경삽목묘 주요 절위를 분석하였다. 화경으로부터 순서대로 5매엽 이상을 가진 마디 6개를 삽목(6 절위, Level 1~6)하여 온실과 생장환경조절실에서 각각 30일간 관리 하였다. 그 결과, 삽목 절위가 기부 쪽으로 내려갈수록 발근율과 액아 생장이 억제되었고, 삽수 잎의 황화 및 낙엽 현상이 조기에 나타났다. 잎의 탄수화물 함량은 발근과 신초발아율에 영향을 주지 않았다. 온실환경에서 1~3 절위, 생장환경조절실 에서 1~2 절위의 생장이 가장 우수하였고, 모두 4절위까지는 정상적인 생장을 보였다. 결과적으로 상업용 장미 시설 생산에서 대량삽목번식을 할 때 화경으로부터 5매엽을 가진 네번 째 마디(level 4)까지 가능할 것으로 확인되었다.

본 연구에서는 절삭식 정미기 도입에 따른 실효성을 분석하기 위해 개발된 절삭식 정미기의 경제성을 비용/편익 분석(B/C ratio), 손익분기점, 기존의 정미기와의 비교 및 수입대체효과의 4가지 측면에서 분석하였다. 절삭식 정미기의 가동률에 따른 비용/편익 비율은 가동률 60%, 80%에서 모두 1 초과로 추정되었다. 손익분기점은 가동률 60%에서는 절삭식 정미기 운용을 시작한 지 3.4년 정도 경과한 시점부터 순이익이 발생하였다. 또한 가동률 80%의 경우 정백미 생산을 시작한 지 66일째부터 수익이 발생하여 절삭식 정미기 운용 후 2.56년 정도부터 순이익이 발생하는 것으로 나타났다. 개발된 절삭식 정미기를 기존의 국산 및 수입 정미기 4종과 비교한 결과 국산에 비해서 가격 및 수리비용에서는 다소 높은 값을 보였으나, 에너지 소비량이 적고 설치공간이 작은 장점을 보였다. 수입된 정미기에 비해서는 에너지 소비량, 가격, 설치공간 및 수리비용에서 충분한 경쟁력을 보였다. 이에 따라 수입된 정미기 100대를 개발된 정미기로 대체할 경우 668억 수준의 높은 수입대체효과를 기대할 수 있을 것으로 나타났으며, 국내 시장에서 절삭식 정미기의 시장점유율을 높일 수 있을 것으로 시사되었다.

CNC cutting process has been mainly used for processing metal materials, and wood processing is also changing to machining by CNC machine. But the researches on the CNC machining of wood and its characteristics were rarely carried out. In this study, we analyzed the machined surface according to the cutting conditions such as the cutting direction, spindle speed, feed rate, cutting depth, chip removal in the CNC machining of wood. The consideration of cutting conditions and their effects on the surface finish will provide possibilities for improving the wood machining processes.

The A182 steel is used in the steam pressure regulator of power plant valves. Since the part is operated under high temperature and high pressure conditions, it is necessary to study the machining characteristics. In this study, EDS analysis of the tool wear shape according to the cutting condition of A182 steel was performed. The A182 steel is identified as a steel belonging to the hardest cutting material and will be used to derive the optimum cutting condition.

The consumption of pre-treated vegetables (including fresh-cut vegetables) has been significantly increased because of their ease of use for cooking. Vegetable cutting machine has been widely utilized for producing fresh-cut vegetables or agricultural products with different sizes; however, its design standard is not specifically established depending on types of agricultural products. Therefore, this study was conducted to determine mechanical properties (compressive and shear force) of targeted agricultural products (radish, carrot, squash, cucumber, shiitake mushroom and sweet potato) for developing multipurpose vegetable cutting machine. According to ASAE standard (s368.3), compressive and shear force of targeted agricultural products were measured by using custom built UTM (universal testing machine). Shape type of samples and speed ranges (5~15 mm/min) of loading rate on bioyield and shear points were varied by targeted agricultural products. The range of averaged bioyield points of targeted agricultural products were between 7.89 and 146.98 N. On the other hands, their averaged shear points were from 22.50 to 53.47 N. Results clearly showed that the bioyield and shear points of targeted agricultural products were thoroughly affected by their components. As accumulating compressive and shear points of agricultural products, it can be technical feasible to establish the design standard and control mechanism of multipurpose vegetable cutting machine.

Numerical analysis was carried out to investigate the variation of stress and strain characteristics for the rail device in stone board cutting system. The maximum equivalent stress and strain from the vertical load acting on the device decrease as the load moves forward. Also, the maximum equivalent stress appears near the end of left, and the equivalent force of right rail device was about 1.8 times higher than that of left rail device. The variation of stress and strain distributions was remarkable at the edge of the device, and it has a strong influence on the bottom and column. These results can be applicable to optimal design of the stone board cutting device for the system safety.

In this study, temperature variation characteristics in the stone board cutting device with sheath heater were analyzed through numerical investigation. Four 2kW sheath heaters whose length and diameter are 1800mm, 11mm are installed, and the initial temperature is -5℃. Also Transient condition is used for temperature variations with the operating time of sheath heater. From the analysis, transient temperature variations of cutting device after operating the sheath heater were predicted. Temperature variations were predicted that mainly appears in part contacted with the sheath heater. The result will be helpful in optimal design for various system equipped with sheath heater.