도라지는 한국, 중국 그리고 일본에서 주로 재배되는 약용 작물이다. 도라지의 뿌리는 사포닌의 함량이 높고 기관지 보 호에 효과가 좋아 약재로 이용이 많이 될 뿐만 아니라 가공식 품, 화장품의 원료로 많이 이용되고 있다. 하지만 도라지의 대 량 생산을 위한 폐쇄형 식물 생산 시스템 내 적정 광 환경에 대 한 기초 데이터가 전무한 실정이다. 본 연구는 도라지의 광도 와 광주기를 구명하기 위해 수행되었다. 도라지는 온도 24.9 ± 0.9℃, 상대습도 53.7 ± 10.9%의 폐쇄형 식물 생산 시스템에 서 48일간 육묘하였다. 광도는 100, 150 및 200 ± 10μmol·m-2·s-1 그리고 광주기는 10/14, 12/12, 14/10h(명기/암기)로 처리하 였다. 가장 높은 광도인 200μmol·m-2·s-1에서 지상부 생육이 가장 우수하였고 12/12와 14/10h 사이에는 유의적인 차이가 나타나지 않았다. 200μmol·m-2·s-1에서 광주기 12/12h의 절 간장은 14/10h보다 유의적으로 짧았다. 200μmol·m-2·s-1에 서 지하부 생육의 경우 광주기 12/12h보다 14/10h의 생육이 우수하였다. 결론적으로, 200μmol·m-2·s-1, 12/12h는 도라지 공정 육묘의 광 환경으로 적합할 것으로 판단된다.

본 연구는 계분의 바이오차 전환을 통해 새로운 처리 방안 및 전량 수입되는 주요 상토 원료의 대체 가능성을 확인하고 농업적으로 활용하기 위해 수행되었다. 계분 바이오차(CMB, chicken manure biochar)는 계분과 목질계 바이오매스를 이용하였으며, 100:0(CMB1), 95:5(CMB2), 90:10(CMB3), 85:15(CMB4), 80:20(CMB5), 75:25(CMB6) 및 70:30(CMB7)의 비율로 각각 혼합하여 혐기성 열분해를 통해 생산하였다. 생산된 계분 바이오차는 비료공정규격과 비교하였을 때 CMB4부터 염분함량이 1.93%로 조건을 충족하였으나 원료인 계분의 염분 변동성과 계분의 활용을 극대화하기 위해 염분함량이 1.80%인 CMB5를 최적 생산조건으로 선정하였다. 계분 바이오차를 이용한 상토(BS, bedsoil) 제조는 상토의 주요 원료인 코코피트 대신 계분 바이오차를 1~5%(CMB+BS 1~5%)의 부피 비율로 대체하여 생산하였다. 계분 바이오차 상토는 혼합 비율에 상관없이 비료공정규격을 준수하였고, 이를 이용하여 배추, 상추, 열무, 무, 완두를 대상으로 비해평가를 진행한 결과, 열무를 제외한 작물의 생육이 계분 바이오차가 1~2% 투입된 처리구에서 대조구와 비교하였을 때 초장은 –7~79.2%, 엽수의 경우 0~50.7% 증가한 것을 확인할 수 있었다. 또한 제작된 계분 바이오차 상토가 상토 공정규격을 충족하였기 때문에 이상의 연구 결과를 통해서 최적 조건으로 생산된 계분 바이오차는 상토 원료로 활용이 가능하다는 것을 확인하였다. 그러나, 계분 바이오차의 투입 수준과 작물에 따른 생육차이가 있어 농업적 활용 가능성을 개선할 수 있는 후속 연구가 필요하다고 판단된다.

Microalgae are efficient fatty acid producers owing to their high photosynthetic activities. They can act as sources of biofuel, feed, and various bioactive compounds. This study aimed to determine optimal culture conditions, including culture medium, temperature, and light intensity, to enhance the biomass and fatty acid content of the indigenous freshwater microalga, Tetradesmus obliquus. Evaluation using a high-throughput photobioreactor revealed that the optimal culture temperature and light intensity were 25°C and 300 μmol m-2 s-1, respectively. Additionally, we optimized components (N, P, and Mg) of the BG-11 medium to enhance the microalgal biomass. Modified BG-11 medium increased the T. obliquus biomass by 37% compared to the standard BG-11 medium. Subsequently, the culture medium was replaced with N- and P-depleted media to determine the abiotic stress factor that could increase the cellular fatty acid content. Notably, fatty acid content was significantly increased from 8.5% up to 14.6% on day 7 of culture in N-deficient (N-P+ and N-P-) media. Sequential optimization effectively increased the biomass by 83% and fatty acid content by >76% in T. obliquus. Our optimization method can be used to enhance the biomass and fatty acid contents of various other microalgae.

The demand for automated diagnostic facilities has increased due to the rise in high-risk infectious diseases. However, small and medium-sized centers struggle to implement full automation because of limited resources. An integrated molecular diagnostics automation system addresses this issue by integrating small-scale automated facilities for each diagnostic process. Nonetheless, determining the optimal number of facilities and human resources remains challenging. This study proposes a methodology combining discrete event simulation and a genetic algorithm to optimize job-shop facility layout in the integrated molecular diagnostics automation system. A discrete event simulation model incorporates the number of facilities, processing times, and batch sizes for each step of the molecular diagnostics process. Genetic algorithm operations, such as tournament, crossover, and mutation, are applied to derive the optimal strategy for facility layout. The proposed methodology derives optimal facility layouts for various scenarios, minimizing costs while achieving the target production volume. This methodology can serve as a decision support tool when introducing job-shop production in the integrated molecular diagnostics automation system

한국형 포장설계법(KPRP)은 한국의 기후, 교통, 재료 조건을 반영하여 개발된 포장설계법으로, 성능 기반 분석과 역학적-경험적 원 리를 결합하여 국내 도로포장의 내구성과 효율성 향상에 기여해왔다. KPRP는 지역별 환경 데이터, 교통 하중, 재료 특성을 고려하 여 최적의 포장 구조를 설계하며, 2011년 개발 이후 도로포장의 수명 연장과 경제성 향상을 이루어냈다. 그러나 KPRP에 적용되는 기후 및 교통 데이터는 2000년대 초반의 자료를 기반으로 하고 있어, 현재 기준으로 약 10년 이상의 차이가 존재한다. 이에 따라 최 신 데이터를 반영하여 포장설계를 개선할 필요성이 제기되고 있다. 본 연구에서는 최근 10년간의 최신 기후 데이터를 활용하여 줄눈 콘크리트 포장(JCP)의 콘크리트 슬래브 컬링 시간을 계산하고, 이를 기반으로 온도응력 및 교통응력의 산정 방식을 현 시점에 맞게 개선하고자 한다. 또한, 2023년 도로포장관리시스템(PMS) 데이 터를 이용하여 한국도로공사가 관리하는 모든 고속국도 중 JCP가 적용된 구간을 대상으로 표면 균열(SD), 설계 차로별 AADT, 관 리구간별 도로 연장, 차로 폭 등의 데이터를 분석하였다. 이를 통해 각 도로의 피로균열율을 산정하고, 고속국도를 대상으로 줄눈 콘 크리트 포장의 전이함수를 개선하여 보다 정밀한 설계를 가능하게 하고자 한다. 본 연구는 최신 기후 및 교통 데이터를 반영한 KPRP 기반 줄눈 콘크리트 포장설계의 실현에 기여할 것으로 기대된다.

본 연구에서는 침지형 평판 분리막 생물반응기에 대해 막간차압(TMP)을 효과적으로 제어 가능하는 사인파형 투 과유속 연속운전(SFCO) 모드를 개발하였다. SFCO 모드의 분리 성능을 평가하기 위해 분리막 생물반응기(MBR)의 표준 작 동 방식인 여과/이완(F/R) 모드와 비교, 평가하였다. 공칭 기공 크기가 0.15 μm인 두 개의 동일한 평판형 정밀여과막 모듈을 활성 슬러지 용액에 침지하여 사인파 유형, 투과유속 및 운전시간에 따른 TMP 변화를 측정하였다. 결과적으로 SFCO 모드는 F/R 모드에 비해 낮은 TMP를 유지하여 분리막 오염을 줄이는 데 효과가 있음을 확인하였다. 특히 사인파형의 최대 투과유속 이 15~20 L/m2·h 범위에서 막오염을 최소화하는 데 효과적이었으며, 이는 기존 MBR의 투과유속 운전 범위로서 그 응용이 기대된다.

Due to the special nature of the rotary type dust remover operating close to a river, more than 80% of the parts that make up the device are made of stainless steel. Stainless steel material is applied to the parts. In addition, sufficient rigidity is required, so the dimensions of the members that affect rigidity, including thickness, are applied excessively, resulting in a large weight. As a result, resistance increases during operation, lowering operating efficiency, and production and maintenance are costly and time-consuming, and maintainability is poor. In particular, when the rake blade is damaged, drainage by the pump cannot be smoothly achieved due to inoperability or performance degradation due to interference with other parts, which can cause serious damage to life and property due to flooding. Accordingly, in this study, a carbon material rake was developed to replace the existing stainless steel rake, and research was conducted to improve and optimize the problems of the existing rake.

Carbon neutrality by 2050 was declared and are focusing on developing innovative energy technologies aimed at reducing greenhouse gas emissions. Active investment and research are underway in the full-cycle development of hydrogen energy technologies, including hydrogen production, storage, transportation, and utilization, which is gaining attention as a promising future eco-friendly energy source. The storage density of liquid hydrogen is 70.79kg/m3, which is higher than the 41kg/m3 of compressed hydrogen at 700bar, making it more suitable for large-scale storage. To store hydrogen at 20K, insulation technologies such as vacuum insulation, powder insulation, or multi-layer insulation (MLI) are typically required. Consequently, there is active research being conducted on the design of insulation systems and materials. However, research on the design for improving the structural integrity of the supports between the inner and outer tanks remains insufficient. n this study, topology optimization was performed for the support design of a liquid hydrogen storage tank using commercial finite element analysis (FEA) software. The structural safety was validated through structural analysis of a simplified self-designed model.

This study analyzes the aerodynamic and structural characteristics of an H-Darrieus vertical-axis wind turbine (VAWT) under varying inlet velocities using transient analysis. The k-ε turbulence model and six-DOF were applied to simulate urban environments in the flow analysis, while the structural analysis considered blade momentum of inertia and RPM conditions. The numerical results showed that the drag and lift forces increased by 60% and 53% respectively from the nominal wind speed to the cut-off wind speed conditions. Structural analysis indicated that the maximum Von-Mises stress in the blade did not exceed the yield strength of 69 MPa of PC-ABS, ensuring structural stability. However, the connecting rod exceeded the yield strength of SPCC 270 MPa, suggesting potential failure due to repeated rotational loads. This study confirms that materials with a yield strength of more than 1,100 MPa required for connecting rods to ensure reliable operation at high wind speed. These findings provide important insights for the design of robust VAWTs suitable for extreme environments.

Water-soluble substances like hydrogen fluoride, generated in semiconductor manufacturing, pose serious health and environmental risks, underscoring the need for effective capture devices. Vertical liquid capture devices help by aggregating and discharging hazardous substances with water, but their design can lead to backflow during abnormal operations, causing unintended releases and impacting efficiency and safety. This study seeks to improve a vertical liquid collection device’s containment performance by optimizing its geometry. The vertical wall was rotated at various angles and directions, and turbulent kinetic energy and streamline distribution were analyzed to assess vortex formation and flow characteristics. These structural modifications identify optimal conditions to control hazardous substance migration, offering insights for future pollutant removal device designs.

최근 농촌 인구 감소와 고령화로 노동력 부족 현상이 심화 되면서 농민들이 인력을 확보하는 데 어려움을 겪고 있다. 기 존의 노지 벼 육묘는 많은 공간과 노동력을 요구하며, 어린 묘 의 품질 관리가 어려운 문제가 있다. 본 연구에서는 컨테이너 형 수직농장을 활용하여 벼 육묘일수를 줄이고, 광 및 양액의 처리에 따른 생육 효과를 확인하였다. ‘고시히카리’와 ‘참드 림’ 두 품종의 벼를 지하수와 희석된 양액을 사용하여 각각 160와 355μmol·m-2·s-1의 광도에서 10일간 컨테이너형 수직 농장에서 재배하였다. 벼 육묘 결과, 모든 품종에서 10일 만에 이앙 가능한 초장을 확보할 수 있었으며, 양액을 처리하지 않 는 저광도에서 경제적 운영이 가능함을 확인하였다. 뿐만 아 니라 육묘된 벼는 순화과정에 문제가 없고, 본답 정식 이후에 도 기존 노지육묘와 생산성이 유사한 것을 확인하였다. 경제 성 분석을 통해 육묘판 생산 시 컨테이너형 수직농장 2동 이상 있을 경우 기존 노지육묘보다 비용 절감이 있음을 확인하였 다. 따라서 컨테이너형 수직농장을 활용한 벼 육묘는 비용 절 감과 노동력 부족 문제 해결에 기여할 수 있는 효과적인 대안 이 될 것으로 기대된다.

본 연구는 사과 ‘홍로’의 생육 시기별 품질 변화를 분석하여 숙기를 진단하기 위한 최적 수확 지표를 선정하고, 기계 수확 이 가능한 사과 ‘홍로’의 품질 기준을 설정하고자 수행되었다. 전라북도 완주군에 위치한 국립원예특작과학원에서 재배된 7년생 사과 ‘홍로’ 품종을 대상으로 2021년부터 2023년까지 만개 후 58－59일(6월 상순)부터 수확 시기가 지난 만개 후 164－173일(9월 하순)까지 10일 간격으로 과실 품질을 조사 하였다. 또한 완주군, 화성시, 포천시에서 수집된 품질 데이터 를 활용하여 지역별 ‘홍로’ 품질 변화를 분석하였다. 과중은 생육이 진전됨에 따라 증가하다가 수확기 직전 250－320g 범 위에 도달했다. 경도와 산도는 생육이 진전되면서 감소했고, 가용성 고형물 함량은 증가하다가 12－14°Brix 에서 더 이상 증가하지 않는 경향을 나타냈다. 또한 당산비는 생육이 진전 될수록 증가하여 수확기에는 50 이상으로 증가했다. 색도 L* 값과 b*값은 증가하다가 수확기에는 급격하게 감소했으며, a* 값은 수확기에 급격히 증가하였다. 전분 함량은 생육 후반부 에 급격히 감소하여 수확기에는 20mg·g-1 이하로 낮아졌다. 전분 함량과 과실 특성들 간의 상관분석을 한 결과, 경도와 산도가 각각 0.86과 0.84로 높은 상관성을 나타냈다. 따라서 경 도와 산도를 최적 수확 지표로 선정하였으며, 수확 가능 최소 품질 범위는 경도 39.7±6.4N, 산도 0.255±0.052%, 가용성 고 형물 함량 13.6±1.3°Brix, 색도 a*값 14.7±12.8로 설정하였 다. 이 기준과 함께 회귀 계수가 높은 비파괴 조사항목인 종경, 횡경, 색도a*값을 활용한다면 기계 수확뿐만 아니라 재배자 에게도 유용한 정보를 제공하여 수확 시기를 최적화시킬 수 있을 것으로 기대한다.

Lightweighting is crucial in various industries, especially for bicycles where weight and stiffness are key. Traditional materials like steel, aluminum, and carbon each have pros and cons. This study compares hybrid tubes made of aluminum and carbon composites with conventional aluminum tubes. Using structural analysis and experimental testing, the hybrid tubes showed a weight reduction of up to 17.25% and maintained acceptable deformation levels. Finite element analysis confirmed these findings, demonstrating the hybrid tubes' potential as superior bicycle frame materials. Future research should focus on long-term durability and fatigue characteristics.

In this study, we explored the design of improved road lighting for drivers and pedestrians using ray-tracing and reverse ray-tracing methods. Conventional road lighting often poses issues such as glare and unevenly illuminated areas, which can compromise safety and efficiency. These problems stem from traditional design approaches focused solely on achieving high luminance and electrical power. However, our research shows that higher brightness or power consumption does not necessarily equate to better road lighting. By applying ray-tracing techniques, we aimed to design a reflector that enhances visibility while being easier on the eyes of both drivers and pedestrians. Our optimized reflector design demonstrated significant improvements in both central and average illuminance levels, all while reducing energy consumption. This study suggests that careful reflector design is crucial for creating safer and more energy-efficient road lighting solutions.

In this study, we explored the design of improved road lighting for drivers and pedestrians using ray-tracing and reverse ray-tracing methods. Conventional road lighting often poses issues such as glare and unevenly illuminated areas, which can compromise safety and efficiency. These problems stem from traditional design approaches focused solely on achieving high luminance and electrical power. However, our research shows that higher brightness or power consumption does not necessarily equate to better road lighting. By applying ray-tracing techniques, we aimed to design a reflector that enhances visibility while being easier on the eyes of both drivers and pedestrians. Our optimized reflector design demonstrated significant improvements in both central and average illuminance levels, all while reducing energy consumption. This study suggests that careful reflector design is crucial for creating safer and more energy-efficient road lighting solutions.

This study aims to optimize the SDC (Spinning Dust Collector) system in amphibious assault vehicle engines through numerical analysis of dust and moisture particle separation efficiency using CFD-DPM. Focusing on an axial cyclone structure, the research evaluates separation efficiency across various particle sizes and flow conditions. The results demonstrate that vortices generated by cyclone blades play a critical role in influencing particle trajectories and improving separation performance. Additionally, the study highlights the significant impact of engine flow conditions and housing design, emphasizing that their careful optimization enhances the system's efficiency in separating dust and water. These findings offer valuable insights into optimizing inlet and outlet flow paths and cyclone housing design, providing a solid foundation for advancing SDC system performance in high-efficiency engines.

In the development of a digital multi-process welding machine, we aimed to analyze the heat dissipation effects resulting from changes in the transformer's shape. Two installation configurations for the transformer, vertical and horizontal, were proposed. Thermal-flow analysis was conducted for the welding machine, taking into account variations in spacing between each proposed configuration. The results indicated that the shape and spacing of the components did not significantly alter the airflow around the reactor coil, which is the main heat-generating component of the machine. When comparing the heat dissipation effects across models with different transformer spacings, it was observed that models with narrower spacing exhibited improved heat dissipation, while the vertical configuration demonstrated a slightly higher heat dissipation effect overall. Transient analysis revealed the irregularities in internal flow and the resulting scattered temperature distribution over time within the welding machine.

Automobiles are an essential means of transporting passengers and cargo, but traffic accidents are inevitable in their operation. These accidents can occur in various forms, such as front, rear, and side collisions. The resulting damage to the vehicle can also be seen similarly; it is inherently distinct: the complexity of repairing the car body makes a simple reliance on textbook knowledge insufficient. Successful correction of the damaged body largely depends on the experience of the practitioner. Discussions on body repair techniques should be based on empirical data reflecting current industry standards and associated costs. The variability of individual repair methodologies can result in significant time and financial expenditure in the field of automotive bodies. Application of new material technologies to vehicle fabrication requires continuous training and empirical research, especially on the body repair process involving new materials. In particular, since the left and right aprons and side members are made of different materials, such as aluminum and high-strength steel, careful restoration of these parts is required. Technical considerations are needed. Interest in safety and environmental impacts. In this study, SPR bonding technology analyzes experimental results.

The multi-local resonance metamaterial is based on the local resonance mechanism of resonators, effectively blocking wave propagation within multiple resonant frequency ranges, a phenomenon known as band gaps. In practical applications for vibration reduction, the goal is to achieve wide-band vibration attenuation at low frequencies. Therefore, this study aims to improve the vibration reduction performance of multi-local resonance metamaterials by lowering the band gap frequency and expanding the band gap width. To achieve this, an objective function was formulated in the optimization problem, considering both the frequency and width of the band gap, with the geometric shapes of the multiple local resonators selected as design variables. The Sequential Quadratic Programming (SQP) technique was employed for optimization. The results confirmed that the band gap was generated at lower frequencies and that the band gap width was expanded.

In various machines used in industrial sites and transportation equipment, fastening structures of bolts and nuts are widely employed. However, conventional Steel sockets, classified as non-explosion-proof materials, have a high likelihood of generating sparks due to friction with components, which can lead to explosions or large-scale fires. To address this issue, this study developed a lightweight explosion-protection socket using AL-7075-T6 aluminum alloy, which is known for its excellent explosion-proof properties. However, due to the inherent characteristics of aluminum, it has lower rigidity compared to Steel, requiring the use of more expensive alloy materials. Therefore, our research team utilized Finite Element Analysis (FEA) and Multi-Objective Genetic Algorithm (MOGA) to optimize the mass and safety factor of the socket, proposing a design that simultaneously achieves both weight reduction and structural stability. The socket developed in this study is approximately 30% lighter than traditional Steel-based sockets while maintaining a safety factor of 1.2 or higher, significantly enhancing operational safety in explosive environments. This research sets a new standard in the design and manufacturing process of explosion-proof sockets and is expected to contribute to the optimization of various explosion-proof equipment in the future.