본 연구는 MRI 검사 시 자기장의 세기 변화와 수신대역폭을 변화시켜 인공 고관절에 의해 나타나는 금속 인공물의 발생 정도를 정량적으로 분석하고 평가하였다. 이를 위해 티타늄 합금 재질의 인공 고관절로 제작한 팬텀을 대상으로 1.5T, 3.0T MR 장비를 사용하여 자기장 세기 변화를 주었으며, 10, 40, 80, 120, 150 Hz/PX로 수신대역폭 변화 를 주어 영상을 획득하였다. 2D FSE 펄스시퀀스로 T2WI 영상을 획득하였고 Image J를 사용하여 금속 인공물의 면적을 신호 소실과 신호 중첩의 합으로 측정하였다. 자기장 세기 차이의 따른 결과 1.5T MRI의 경우 평균 4772.45 ㎟, 3.0T MRI의 경우 평균 5267.41 ㎟로 나타났으며 수신대역폭 10, 40, 80 Hz/PX은 금속 인공물 발생 면적이 큰 폭으로 감소하였지만 120, 150 Hz/PX 에서는 금속 인공물의 감소폭은 상대적으로 적었으며 이는 통계적 으로 유의한 차이를 보였다(p<0.05). 따라서, 저자기장(1.5T)을 사용하였을 때 금속 인공물 감소에 효과적이며 수신 대역폭을 늘려 검사했을 때는 금속 인공물을 줄일 수 있지만 SNR의 감소를 초래하므로 합리적인 수신대역폭 선택이 필요하다.
The textile tentering process generates exhaust gases characterized by elevated temperature and humidity, accompanied by complex odors, fine particulate matter, and visible white smoke, all of which frequently contribute to public grievances and environmental concerns. This study evaluated a field-installed, multi-stage emissioncontrol system consisting of a scrubber, a wet electrostatic precipitator (WEFC), and a heat exchanger, with emphasis on the effect of routine plate cleaning over a ht ree-month operation. Real-time monitoring at 5-minute intervals measured temperature, humidity, total volatile organic compounds (TVOCs), particulate matter (PM2.5, PM10, TSP), and odor intensity. Odor activity values (OAVs) and odor contributions (OC) were determined from samples collected according to the Korean Odor Measurement Standard. The emission-control system reduced exhaust temperature from 150oC to below 50oC while maintaining stack outlet temperature differences within 5oC, thereby suppressing visible white smoke. The multistage system achieved mean removal efficiencies of 88.6±5.0% for TVOCs and 96.2±6.5% for PM10, with a gravimetric PM10 removal of 99.4%. Weekly cleaning of the electrostatic plates constrained day-to-day variability in odor and PM levels within ±10%, significantly lowering the frequency of white-smoke episodes. Isovaleraldehyde and acetaldehyde accounted for >90% of total OAVs, indicating the need for supplementary treatment targeting aldehydes. These results provide quantitative evidence to guide maintenance scheduling and emission-control policy for the textile processing industry.
This study details the synthesis and characterization of phosphorus-sulfur co-doped graphitic carbon nitride quantum dots (PSQ) and their integration into g-C3N4 (CN) to form PSQ/CN composites for the enhanced photocatalytic reduction of Cr(VI) and fluorescence detection. Incorporating PSQ into CN was found to significantly improve light absorption, narrow the band gap, and enhance charge separation efficiency. Notably, the composite material exhibits superior photocatalytic performance, especially in acidic environments. Photocatalytic assessments utilizing Cr(VI) demonstrated that the PSQ/ CN composite outperformed both undoped and singly doped materials, indicating its superior photocatalytic activity. Additionally, phosphorus-sulfur co-doping markedly increased the fluorescence quantum yield of PSQ. The fluorescence intensity exhibited a linear decrease with increasing Cr(VI) concentrations, enabling sensitive and selective detection of Cr(VI) with a detection limit as low as 1.69 μmol/L. Collectively, the PSQ/CN composite and PSQ highlight their potential for photocatalysis and fluorescence-based detection of Cr(VI), providing high sensitivity, selectivity, and synergistic interactions within the composite material.
In the pursuit of achieving in-situ real-time detection of methanol production rate during the photocatalytic reduction of CO2, we developed a methanol sensor using a copolymer-coated fiber Bragg gratings. The theoretical model of methanol measurement by sensor was established. The effect of methanol-selective sensitive material and its thickness on the performance of the sensor were investigated. Humidity and temperature interference to sensor measurements was compensated. Furthermore, TiO2 photocatalyst was prepared and the photocatalytic reactor was constructed. The methanol production rate in the photocatalytic CO2 reduction process was monitored by the prepared sensor in-situ. The results highlight that the fiber Bragg grating methanol sensor with 600 nm-thick poly(N-isopropylacrylamide)/polymethyl-methacrylate coating showed a high sensitivity, lower limit of detection, fast response and recovery speed, and high selectivity. The methanol generation rate of TiO2 photocatalytic reduction of CO2 measured by gas chromatograph and prepared fiber Bragg grating methanol sensor was 1.42 and 1.53 μmol/g-cat·h, respectively, the error of the two detection methods was 7.86%. This highlights the efficacy of the developed fiber Bragg grating methanol sensor for real-time in-situ detection of the methanol production rate during the photocatalytic reduction of CO2.
Efficient yet realistic ship routing is critical for reducing fuel consumption and greenhouse-gas emissions. However, conventional weather-routing algorithms often produce mathematically optimal routes that conflict with the paths mariners use. This study presents a hybrid approach that constrains physics-based weather routing within an AISderived maritime traffic network (MTN) built from one year of global Automatic Identification System data. The MTN represents common sea lanes as a graph of approximately 10,956 waypoints (nodes) and 17,561 directed edges. Using this network, an optimal low-emission route is computed via graph search and then compared against both a traditional unconstrained route and an advanced weather-routing model (VISIR-2). In a May transitionseason case (Busan–Singapore voyage), the AIS-constrained route reduced fuel consumption and CO₂ emissions by about 1.9% relative to the fastest feasible route, while closely following real traffic corridors (over 90% overlap with actual 2024 AIS tracks). While this 1.9% saving does not reach the high-end potential of an unconstrained, state-of-the-art model like VISIR-2 (which can demonstrate double-digit savings in certain conditions), it is achieved with an increase in transit time of ~6.5 h (≈3.2%). This represents a crucial trade-off, prioritizing operational realism and adherence to real-world traffic corridors over maximum theoretical efficiency.
Baicalin is known to exhibit neuroprotective effects during brain injury through its antioxidant and anti-inflammatory functions. Moreover, γ-enolase is specifically expressed in nerve cells and exhibits neuroprotective properties. In this study, we investigated whether baicalin regulates γ-enolase expression in an moddle cerebral artery occulsion (MCAO)-induced brain injury model. Adult male rats were intraperitoneally injected with baicalin (100 mg/kg) or phosphate-buffered saline (PBS) immediately after right MCAO surgery. Neurological behavior tests were performed 24 hours after surgery and brain water content was evaluated. Right cortical tissue was collected. Western blot analysis were conducted to elucidate γ-enolase expression in MCAO animals treated with baicalin. In addition, γ-enolase expression was analyzed using immunofluorescence staining. MCAO animals administered PBS displayed severe behavioral impairments and edema, whereas baicalin administration alleviated these disorders, demonstrating the protective effects of baicalin against ischemic damage. Western blot analysis results showed that MCAO-induced damage decreased γ-enolase expression, and baicalin treatment mitigated this reduction. These findings were confirmed through immunofluorescence staining. Since γ-enolase is known to contribute to neuroprotective effects, these results suggest that baicalin alleviates neurobehavioral impairments in stroke animals and exerts neuroprotective effects by attenuating the decline in γ-enolase expression caused by brain injury. In conclusion, we demonstrated that baicalin regulates γ-enolase expression during cerebral ischemic damage.
고속 스핀 에코를 이용한 T2 강조 영상에서 재자화 펄스의 FA 크기 변화에 따라 발생하는 전자파 유도 열을 정량적 으로 측정하고, 상변화 물질의 열 저장 특성을 활용하여 열 발생을 효과적으로 감소시킬 수 있는 방안을 모색하고자 하였다.실험에서는 상변화 물질을 적용한 조건과 적용하지 않은 조건에서 각각 FA의 증가에 따른 온도 변화를 평가 하였으며, 그 결과는 다음과 같다. 고속 스핀 에코 기반 T2 강조 영상에서 FA 크기의 증가에 따라 계산된 SAR 값은 상변화 물질 적용 여부와 관계없이 각각 0.64±0.048, 0.87±0.042, 1.33±0.042, 1.88±0.031 W/kg로 유사한 경향을 보였다.온도 변화 분석 결과, 상변화 물질을 적용하지 않은 조건에서 돼지 비계의 초기 스캔 온도는 19.3°C였으며, FA 증가에 따라 최대 21.9°C까지 상승하여 총 2.6°C의 온도 증가가 관찰되었다. 반면, 상변화 물질 을 적용한 조건에서는 동일한 초기 온도 19.3°C에서 19.7°C까지 상승하는 데 그쳐 0.4°C의 온도 증가만 나타났으며, 두 조건 간 약 2.2°C의 온도 차이를 보였다. 한편, 돼지 비계에 온열 경피 패치를 부착한 조건에서도 유사한 경향이 나타났다. 상변화 물질을 적용하지 않은 경우, 스캔 시작 온도 20.6°C에서 23.1°C로 총 2.5°C 상승하였으나, 상변화 물질을 적용한 경우에는 20.1°C에서 20.5°C로 0.4°C 상승하는 데 그쳐 약 2.1°C의 차이를 나타냈다. 이와 같은 결과 는 상변화 물질이 반복되는 고주파 자극에 의해 유도되는 온도 상승을 효과적으로 억제할 수 있음을 확인하였다. 전자파 흡수율 및 열 발생 저감에 대한 과학적 근거를 제공함으로써, 향후 MRI 검사 환경의 안전성 향상에 기초자료 로 활용되기를 기대한다.
In this study, comparative combustion was performed in a 3-ton flue tube boiler for emulsified oil manufactured by using 15% water and approximately 1% carbide aqueous solution as an emulsifier in Bunker-C oil, and the characteristics of exhaust emissions were analyzed. As a result of performing comparative combustion under the same ambient environment and external conditions, the exhaust gas temperature decreased by approximately 3.93% from 183.76℃ for bunker-C to 176.52℃ for EM15, and the oxygen concentration increased by approximately 2.96% from 9.72% to 12.68% . Carbon dioxide decreased by approximately 2.3% from 8.49% for bunker-C to 6.19% for EM15, indicating that EM15 has a greenhouse gas reduction effect. When the standard oxygen concentration of 4% was applied, nitrogen oxides decreased by approximately 43.17% from 130.59 ppm for Bunker-C to 74.21 ppm for EM15, and sulfur oxides decreased by approximately 53.05% , confirming the excellent emission reduction characteristics of emulsified fuel oil. Therefore, it is expected that replacing emulsified fuel oil in boilers using Bunker-C oil will enable response to increasingly strengthened emission regulations.
The IMO’S 72nd MEPC meeting proposed the goal of reducing greenhouse gas emissions by up to 50% by 2050. Thus, various eco-friendly fuels are proposed as alternatives, but there are also various issues that need to be tackled, such as storage stability and supply system issues in a special environment a ship has. Therefore, in this study, the possibility of reducing greenhouse gases was analyzed by applying MGO as an alternative to boilers operated with HFO, a Bunker-C series. As a result, the exhaust gas temperature decreased by about 11.54% from 316.9℃ to 280.3℃, and the amount of oxygen content increased by about 0.38% from 6.27% to 6.65%. It can be seen that carbon monoxide can be reduced by about 45.28% by simply converting fuel from 45.29 ppm to 24.78 ppm, and carbon dioxide, which is a typical greenhouse gas, can be reduced by about 0.49% from HFO by 11.08% to MGO by 10.59%. This means that some greenhouse gas reduction is possible only by shifting between ship fuels that satisfy ISO-8217, but since there are limitations to achieving strong carbon neutrality proposed by IMO, it will be necessary to actively utilize the use of various alternative fuels in the future.
Electrochemical reduction of carbon dioxide is a crucial energy conversion protocol involving two significant processes: converting CO2, a greenhouse gas, into value-added products and reducing fossil fuel usage to produce fuels or chemical products. Moreover, the production of CO from the carbon dioxide reduction reaction is highly substantial since it is a twoproton/ electron reaction, and it also finds potential applications in chemical, metallurgical, and pharmaceutical industries. Among the various classes of electrocatalytic materials, single-atom catalysts have attracted great attention because of their high atom utilization. Here, we survey the recent research trends involved in the preparation of single atom-based electrocatalysts for the generation of carbon monoxide from the electroreduction of carbon dioxide.
In four-wheel-drive vehicle, improving traction with the road surface enhances the vehicle's ability to respond to various driving conditions, increasing its overall versatility. Consequently, various studies have been conducted on four-wheel-drive vehicles that support torque distribution through electronic control. The driving unit that operates the transfer case assists in smooth torque distribution by providing high torque. Therefore, this study developed a reduction mechanism by vertically arranging a planetary gear set in the driving unit to increase the reduction ratio. To achieve this, a common ring gear with 52 teeth was used, and the design included a first-stage planetary gear with a sun gear having 18 teeth, a planet gear with 17 teeth, a second-stage sun gear with 12 teeth, and a planet gear with 20 teeth. The corresponding tooth profiles and structures were also designed. Based on this, a transfer case drive reduction module was developed, which improved torque performance: the first-stage planetary gear system provides 4.23 kgf·m of torque, and the second-stage planetary gear system achieves a final torque of 5.98 kgf·m
연구는 내항여객선의 상가 주기를 조정함으로써 연료비를 포함한 운항비용의 절감 가능성을 분석하는 데 목적이 있다. 선박의 연료 효율에 영향을 미치는 요소 중 하나인 선체부착생물은 선박과 해수 간 마찰을 증가시켜 더 많은 연료 소모를 유발하는 것으로 알려 져있다. 선박안전법에 따라 감항성 유지 및 운항 안전을 위해 매년 정기검사 또는 제1종 중간검사를 받아야 하는 내항여객선은 일반적으 로 이러한 검사에 대비하여 연 1회의 상가 수리를 통해 선체부착생물을 제거한다. 이에 본 연구에서는 실제 운항 중인 3척의 내항여객선 을 대상으로 AIS 데이터, 항해일지 및 상가 수리 비용 등의 자료를 수집하고, 연간 표준운항비용을 산정하였다. 이를 바탕으로 MATLAB 기반의 시뮬레이션을 통해 각 선박의 상가 주기별 운항 비용 산출하여 비용 절감 효과를 분석하였다. 분석 결과, 선박별로 최대 비용 절 감 효과가 나타나는 시점이 상이하였으나, 연료비 절감과 추가 상가 비용 간의 균형점이 존재함을 확인하였다. 본 연구는 내항여객선의 선체 유지관리에 있어 상가 주기 조정이라는 운영 전략을 정량적으로 분석하였으며, 선사의 유지보수 계획 수립에 실질적인 근거를 제공 한다는 점에서 실무적 의의가 있다.
This study aims to enhance the efficiency of the after-sales service (A/S) process for commercial trucks by implementing a data-driven approach. Traditional A/S methods result in long repair wait times, especially for intermittent faults requiring symptom reproduction. To address this, a system that records Diagnostic Trouble Code (DTC) and Vehicle Running Mode (VRM) data at failure moments is proposed. By storing data from 10 seconds before and after an event, fault diagnosis can be performed without symptom reproduction. Additionally, for exported vehicles, stored data enables remote analysis, overcoming real-time data limitations due to varying environmental factors. This approach improves maintenance reliability, optimizes repair accuracy, and supports proactive quality improvements for newly developed vehicles.
The purpose of this study is to examine the application and effectiveness of tuned mass dampers for reducing cabinet vibration in plants. Cabinet with lower structural rigidity than plant subject to seismic design standards is susceptible to resonance. SolidWorks was used for 3D modeling of the cabinet, and ANSYS Workbench was used to create a mesh. The vibration characteristics of the cabinet were investigated through modal analysis, and the possibility of resonance and vibration reduction performance of the cabinet were evaluated. The number of modes in the cabinet was set to 100, and the frequency and modal participation mass ratio of each mode were calculated. In order to examine the possibility of vibration reduction by tuned mass dampers, the vibration response characteristics of cabinets with and without tuned mass dampers were compared. The analysis results showed that the third mode had a significant effect on the dynamic behavior of the cabinet and that the modal participation effective mass ratio was larger than that of other vibration modes. And as the mass of the tuned mass damper increased, the vibration response of the cabinet decreased significantly, and the peak value of the cabinet decreased by up to 52%.