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Determination of more than 500 Pesticide Residues in Hen Eggs by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) and Gas Chromatography-Tandem Mass Spectrometry (GC/MS/MS)

  • Golge, Ozgur;Liman, Turan;Kabak, Bulent
    • 한국축산식품학회지
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    • 제41권5호
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    • pp.816-825
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    • 2021
  • This study aims to validate a fast method of simultaneous analysis of 365 LCamenable and 142 GC-amenable pesticides in hen eggs by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS), respectively, operating in multiple reaction monitoring (MRM) acquisition modes. The sample preparation was based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction. Key method performance parameters investigated were specificity, linearity, limit of quantification (LOQ), accuracy, precision and measurement uncertainty. The method was validated at two spiking levels (10 and 50 ㎍/kg), and good recoveries (70%-120%) and relative standard deviations (RSDs) (≤20) were achieved for 92.9% of LC-amenable and 86.6% of GC-amenable pesticide residues. The LOQs were ≤10 ㎍/kg for 94.2% of LC-amenable and 92.3% of GC-amenable pesticides. The validated method was further applied to 100 egg samples from caged hens, and none of the pesticides was quantified.

선회유동을 이용한 마이크로버블 발생기의 다상유동 전산유체역학 해석 (Multiphase CFD Analysis of Microbubble Generator using Swirl Flow)

  • 윤신일;김현수;김진광
    • 열처리공학회지
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    • 제35권1호
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    • pp.27-32
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    • 2022
  • Microbubble technology has been widely applied in various industrial fields. Recently, research on many types of microbubble application technology has been conducted experimentally, but there is a limit in deriving the optimal design and operating conditions. Therefore, if the computational fluid dynamics (CFD) analysis of multiphase flow is used to supplement these experimental studies, it is expected that the time and cost required for prototype production and evaluation tests will be minimized and optimal results will be derived. However, few studies have been conducted on multiphase flow CFD analysis to interpret fluid flow in microbubble generators using swirl flow. In this study, CFD simulation of multiphase flow was performed to analyze the air-water mixing process and fluid flow characteristics in a microbubble generator with a dual-chamber structure. Based on the simulation results, it was confirmed that a negative pressure was formed on the central axis of rotation due to the strong swirling flow. And it could be seen that the air inside the suction tube was introduced into the inner chamber of the microbubble generator. In addition, as the high-speed mixed fluid collided with external water sucked by the negative pressure near the outlet, a large amount of microbubbles was ejected due to the shear force between the two flows flowing in opposite directions.

A Study on the Urban Air Mobility(UAM) Operation Pilot Qualification System

  • Kim, Su-Ro;Cho, Young-Jin;Jeon, Seung-Mok
    • International Journal of Internet, Broadcasting and Communication
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    • 제14권1호
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    • pp.201-208
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    • 2022
  • As around the world, ground and underground transportation capacity is reaching its limit, centering on urban areas. As urban traffic becomes congested, time and cost are astronomical, and environmental destruction caused by urban pollution is becoming increasingly serious. As a way to solve this problem, the means of flying over the air are in the spotlight as the next generation of future transportation, and the concept of urban air mobility (UAM, Urban Air Mobility) is defined as systematic planning. The development of an electric-powered vertical take-off (eVTOL) aircraft that obtains electric power through a battery using a personal aerial vehicle (PAV) as a means of transportation has accelerated. As the aircraft development of new technology aircraft in the evtol method is actively carried out, the need to prepare systems such as aircraft certification standards, pilot qualification systems, and qualification management is emerging. The Federal Aviation Administration (FAA) and the European Union Aviation Safety Agency (EASA), which lead international standards, announced new special technical conditions and temporary regulations SCVTOL-01, respectively. However, the pilot qualification system for operating the uam aircraft has not yet been clearly announced. Therefore, this paper analyzes the recently announced FAA regulations and EASA regulations to identify differences and directions in perspectives on UAMs and study the existing vertical take-off and landing aircraft (VTOL) pilot qualification system to present directions for qualification classification.

Vertically aligned cupric oxide nanorods for nitrogen monoxide gas detection

  • Jong-Hyun Park;Hyojin Kim
    • 한국표면공학회지
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    • 제56권4호
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    • pp.219-226
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    • 2023
  • Utilizing low-dimensional structures of oxide semiconductors is a promising approach to fabricate relevant gas sensors by means of potential enhancement in surface-to-volume ratios of their sensing materials. In this work, vertically aligned cupric oxide (CuO) nanorods are successfully synthesized on a transparent glass substrate via seed-mediated hydrothermal synthesis method with the use of a CuO nanoparticle seed layer, which is formed by thermally oxidizing a sputtered Cu metal film. Structural and optical characterization by x-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy reveals the successful preparation of the CuO nanorods array of the single monoclinic tenorite crystalline phase. From gas sensing measurements for the nitrogen monoxide (NO) gas, the vertically aligned CuO nanorod array is observed to have a highly responsive sensitivity to NO gas at relatively low concentrations and operating temperatures, especially showing a high maximum sensitivity to NO at 200 ℃ and a low NO detection limit of 2 ppm in dry air. These results along with a facile fabrication process demonstrate that the CuO nanorods synthesized on a transparent glass substrate are very promising for low-cost and high-performance NO gas sensors.

THE EFFICIENT ESTIMATE OF ENVIRONMENTAL MANAGEMENT COSTS IN THE CONSTRUCTION SITES

  • Hyuk Moon;Sung-Jin Kim;Jae-Jun Kim
    • 국제학술발표논문집
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    • The 1th International Conference on Construction Engineering and Project Management
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    • pp.437-446
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    • 2005
  • Recently as people's values are changing from development phase into running stage after quality of life, so that the needs of environmentally friendly construction are gradually increasing. Also populace discontent about the pollution during construction process such as the noise and vibration caused by construction machinery is increasing. Even though it is impossible to eliminate the construction pollution fully, it is necessary to make efforts to reduce construction pollution to a minimum. In terms of construction site operating, the first possible step for solving these matters directly is that the necessary sum of expenses must be secured as the environmental management costs in the conceptual phase. However, in fact, the environmental management costs have not been secured in the budget. Generally it is the major reason not arising proper activities to prevent the pollution in the construction site. The purpose of this research is to suggest the efficient budgeting method regarding Environmental management costs to ensure the necessary sum of environmental management expenses. To provide an efficient budgeting method, interviews with the person in charge of environment management was conducted. 78 construction sites was surveyed and environmental management costs were analyzed through their historical data from the survey. According to the results of analysis, the ratio of environmental management costs is revealed 0.45% of construction cost as average comparing 0.2% of legal limit. And usually the environmental management cost was appropriated into the safety management budget. So it is needed to isolate environmental management budget securely and modify the ratio of Environmental conservation Costs in Construction Technology Management Act.

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Retrieval methodology for similar NPP LCO cases based on domain specific NLP

  • No Kyu Seong ;Jae Hee Lee ;Jong Beom Lee;Poong Hyun Seong
    • Nuclear Engineering and Technology
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    • 제55권2호
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    • pp.421-431
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    • 2023
  • Nuclear power plants (NPPs) have technical specifications (Tech Specs) to ensure that the equipment and key operating parameters necessary for the safe operation of the power plant are maintained within limiting conditions for operation (LCO) determined by a safety analysis. The LCO of Tech Specs that identify the lowest functional capability of equipment required for safe operation for a facility must be complied for the safe operation of NPP. There have been previous studies to aid in compliance with LCO relevant to rule-based expert systems; however, there is an obvious limit to expert systems for implementing the rules for many situations related to LCO. Therefore, in this study, we present a retrieval methodology for similar LCO cases in determining whether LCO is met or not met. To reflect the natural language processing of NPP features, a domain dictionary was built, and the optimal term frequency-inverse document frequency variant was selected. The retrieval performance was improved by adding a Boolean retrieval model based on terms related to the LCO in addition to the vector space model. The developed domain dictionary and retrieval methodology are expected to be exceedingly useful in determining whether LCO is met.

A Study on the Institutional Improvements in the Operation and Management of Underground Shopping Malls

  • KIM, Gi-Pyoung;SEO, Jung Hwa;LEE, Yong-Kyu;LEE, Geun-Woo;YOO, Chang-Kwon
    • 융합경영연구
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    • 제10권1호
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    • pp.15-26
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    • 2022
  • Purpose: The purpose of this study is to analyze the method of calculating the usage fee, rent, and lease rights of public goods necessary for the operation and management of the underground shopping mall, and to suggest systematic improvement points for the operation of the underground shopping mall. Data and Methodology: First, ordinances and regulations related to common property were investigated. Second, previous studies were analyzed. A survey was conducted with five questions that conflict with the interests of underground shopping mall merchants among the ordinances and operating systems related to the current underground shopping malls' common property. Results: Underpass merchants wanted monthly payment for the use of common property, and merchant organizations wanted to limit the increase rate with the right to use. They asked for the property value due to donation to be excluded from the loan fee, they wanted to revise the Common Property Act on the transfer of lease rights, and they wanted to revise the loan contract renewal period. Conclusion: There is a need to improve the laws and systems for underground shopping malls, and it will have to be negotiated according to the opinions of the merchants gathered among them, and it will have to be implemented in stages in the long term.

고압축비 전기점화 천연가스 발전용 엔진에서 앳킨슨 사이클 적용을 통한 열효율 향상 (Improvement of Thermal Efficiency using Atkinson Cycle in a High-Compression Ratio, Spark-Ignition, Natural Gas Engine for Power Generation)

  • 이준순;박현욱;오승묵;김창업;이용규;강건용
    • 한국분무공학회지
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    • 제28권2호
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    • pp.55-61
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    • 2023
  • Natural gas is a high-octane fuel that is effective in controlling knocking combustion. In addition, as a low-carbon fuel with a high hydrogen-carbon ratio, it emits less carbon dioxide and almost no particulate matter compared to conventional fossil fuels. Stoichiometric combustion engines equipped with a three-way catalyst are useful in various fields such as transportation and power generation because of their excellent exhaust emission reduction performance. However, stoichiometric combustion engines have a disadvantage of lower thermal efficiency compared to lean combustion engines. In this study, a combination of high compression ratio and Atkinson cycle was implemented in a 11 liter, 6-cylinder, spark-ignition engine to improve the thermal efficiency of the stoichiometric engine. As a result, pumping and friction losses were reduced and the operating range was extended with optimized Atkinson camshaft. Based on the exhaust gas limit temperature of 730℃, the maximum load and thermal efficiency were improved to BMEP 0.66 MPa and BTE 35.7% respectively.

Simscape 기반 6자유도 필드로봇 시뮬레이션 모델에 관한 연구 (A Study on Simscape based 6DOF Field Robot Simulation Model)

  • 최성웅;곽경신;레쾅호안;양순용
    • 드라이브 ㆍ 컨트롤
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    • 제19권2호
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    • pp.1-10
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    • 2022
  • Field robots operate in various areas, including construction, agriculture, forestry and manufacturing. Typical tasks of field robots used in various areas include excavation, flattening, and demolition. Such tasks are often accomplished in narrow alleys or indoors. In the case of field robots, there is a limit to working in a small space. Thus, to compensate for these shortcomings, many field robots equipped with Tiltrotators have recently been observed. The advantages of Tiltrotator are improved task efficiency and reduced operating time by reducing unnecessary behavior. We need simulation models that can improve the ability of new people to work and simulate tasks in advance. Thus, in this paper, we developed a simscape-based simulation model and modeling of 6DOF systems for field robots equipped with Tiltrotator. Dynamic modeling of field robot 3D models using Simcape multibody and hydraulic systems of field robots using Simcape Hydraulics were modeled. We applied a PID controller to create a control system that operates along the input angle. Simulation results show that errors occur when comparing input and output angles, but overall, they move along input angles.

Collision-Damage Analysis of a Floating Offshore Wind Turbine Considering Ship-Collision Risk

  • Young-Jae Yu;Sang-Hyun Park;Sang-Rai Cho
    • 한국해양공학회지
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    • 제38권3호
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    • pp.124-136
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    • 2024
  • As the number of offshore wind-power installations increases, collision accidents with vessels occur more frequently. This study investigates the risk of collision damage with operating vessels that may occur during the operation of an offshore wind turbine. The floater used in the collision study is a 15 MW UMaine VolturnUS-S (semi-submersible type), and the colliding ships are selected as multi-purpose vessels, service operation vessels, or anchor-handling tug ships based on their operational purpose. Collision analysis is performed using ABAQUS and substantiation is performed via a drop impact test. The collision analyses are conducted by varying the ship velocity, displacement, collision angle, and ship shape. By applying this numerical model, the extent of damage and deformation of the collision area is confirmed. The analysis results show that a vessel with a bulbous bow can cause flooding, depending on the collision conditions. For damage caused by collision, various collision angles must be considered based on the internal stiffener arrangement. Additionally, the floater can be flooded with relatively small collision energy when the colliding vessel has a bulbous bow.