• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 추계학술대회 논문집
• /
• pp.1776-1781
• /
• 2008

To reduce interior noise of running vehicles, a floating floor construction has been widely used in recent railway industry. Among the key factors of the floating floor design, dynamic stiffness is of most important in acoustical point of view. Sometimes hard rubber type supports have often been selected due to the other design constraints such as heavy load condition, durability of rubber element and its cost etc., even though it seems like the softer support, the better isolation of noise and vibration. In this paper two representative floor supports have been considered to evaluate their effectiveness in interior noise contribution: one is a soft rubber and another is a relatively hard one. From the measured dynamic stiffness of the specimens, equivalent stiffness of actual floating floor has been derived to use in the analytical models. Calculated air-borne and structure-borne noise insulation properties of the floating floors have been compared with experiments in prototype car. In full car model interior noise levels of running vehicles have been predicted to quantify the effectiveness of the two different floating support materials and verified through the measured inside noise levels of actual train as well. By comparison with difference of running noise levels two materials for floor support can be investigated quantitatively so that it could be applied in floating floor design.

• 자원ㆍ환경경제연구
• /
• 제25권4호
• /
• pp.545-564
• /
• 2016

최근 우리나라는 미세먼지 및 초미세먼지 문제가 크게 대두되면서 대기오염문제에 대한 효과적인 해결책이 중요해진 시점에 있다. 본 연구는 대기오염의 원인을 계량경제모형을 통해 찾아보고, 경유가격 인상정책이 경유소비 감소와 대기오염의 저감에 기여하는지를 분석해보았다. 대기오염물질로는 TSP, PM10, $NO_X$, $SO_X$, CO, VOC가 포함되었다. 분석 결과 CO를 제외하고 모든 오염물질에서 경제성장은 역U자형의 영향을 미치는 것으로 나타났고, 소비자 물가지수, 화력발전설비, 경유소비, 황사발생일수, 천연가스버스, 운수업체 사업장수, 평균기온, 제조업체 사업장수 등이 대기오염에 영향을 미치는 변수로 나타났다. 또한 경유가격이 1% 상승하면 대기오염물질은 단기적으로는 0.07~0.12% 감소하고, 장기적으로는 0.31~0.53% 감소하는 것으로 나타났다. 따라서 환경개선부담금의 형태로 경유가격을 올리고, 그 수입원을 바이오디젤 보급 지원에 사용한다면 보다 효과적인 대기오염 개선을 기대할 수 있다.

• 한국환경보건학회지
• /
• 제49권5호
• /
• pp.275-288
• /
• 2023

Background: When basic local governments want to improve their air quality management policies, they need fundamental evidence, such as the effectiveness of current policies or scenario results. Objectives: The purpose of this study is to lay the groundwork for a process to calculate air pollutant reduction from basic local government air quality policies and provide numerical estimates of PM_2.5 concentrations following improved policies. Methods: We calculated the amount of air pollutant reduction that can be expected in the research region based on the Gyeonggi-do Air Environment Management Implementation Plan issued in 2021 and guidelines from the Korean Ministry of Environment. The PM_2.5 concentration variations were numerically simulated using the CMAQ (photochemical air quality model). Results: The research regions selected were Suwon, Ansan, Yongin, Pyeongtaek, and Hwaseong in consideration of population, air pollutant emissions, and geographical requirements. The expected reduction ratios in 2024 compared to 2018 are CO (3.0%), NO_x (7.9%), VOCs (0.7%), SO_x (0.1%), PM₁₀ (2.4%), PM_2.5 (6.1%), NH₃ (0.05%). The reduced PM_2.5 concentration ratio was highest in July and lowest in April. The expected concentration reduction of yearly mean PM_2.5 in the research region is 0.12 ㎍/m³ (0.6%). Conclusions: Gyeonggi-do is now able to quickly provide air pollutant emission reduction calculations by respective policy scenario and PM_2.5 simulation results, including for secondary aerosol particles. In order to provide more generalized results to basic local governments, it is necessary to conduct additional research by expanding the analysis tools and periods.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2005년도 동계학술발표대회 논문집
• /
• pp.300-305
• /
• 2005

The present experimental study investigates single-phase heat transfer coefficients downstream of support grid in $6{\times}6$ rod bundles. Support grid with split mixing vanes enhance heat transfer in rod bundles by generating it make turbulence. But this turbulence is confined to short distance. Support grid with LSVF mixing vanes enhanced heat transfer to longer distance. The corresponding Reynolds number investigated in the present study is Re=30,000. The heat transfer coefficients are measured using heated and unheated copper sensor.

• Geomechanics and Engineering
• /
• 제17권6호
• /
• pp.573-581
• /
• 2019

Excavation of underground cavern and shaft was proposed for the construction of a ventilation facility in an urban area. A shaft connects the street-level air plenum to an underground cavern, which extends down approximately 46 m below the street surface. At the project site, the rock mass was relatively strong and well-defined joint sets were present. A kinematic block stability analysis was first performed to estimate the required reinforcement system. Then a 3-D discontinuum numerical analysis was conducted to evaluate the capacity of the initial support and the overall stability of the required excavation, followed by a 3-D continuum numerical analysis to complement the calculated result. This paper illustrates the application of detailed numerical analyses to the design of the required initial support system for the stability of underground hard rock mining at a relatively shallow depth.

• 한국항해항만학회지
• /
• 제43권2호
• /
• pp.86-92
• /
• 2019

IMO has enacted a convention that air pollution due to emissions of ships and sulfur oxides emissions should be significantly reduced by 2020. Based on the current support policies, this work intended to draw up the government support plans required by the shipping companies. Analytic Hierarchy Process analysis was done with factors derived from brainstorming and literature studies. The analysis results showed that the cost factor was generally the most important criterion and the Financial Aid was relatively more important within this cost factor. The policy implications for the regulation of sulfur oxides emissions was provided.

• 한국대기환경학회지
• /
• 제25권2호
• /
• pp.167-174
• /
• 2009

The AIRWARE System was developed from one of the EUREKA PROJECT E!3266-EUROENVIRON WEBAIR System. The AIRWARE can nowcast and forecast the air quality of Seoul and Gyeonggi-do regions. To nowcast and forecast concentration of pollutants, MM5, AERMOD/CAMx, and SMOKE Models were used for each meteorologic data, measured data, and emission data. All DB were constructed for 2001 year. The episode analysis and time series analysis were accomplished to analyze the AIRWARE reliability. The simulated results were very well agreed with measured result for measured pollutants and meteorological data. The developed AIRWARE system can analyze with real-time, support web-based air quality information. This information can used with policy data to manage the air quality and prepare reduction plan in air impact assessment or air environmental plan.

• 한국산업융합학회 논문집
• /
• 제23권3호
• /
• pp.445-452
• /
• 2020

The air cleaning unit of K00 IFV(or Infantry Fighting Vehicle) has important roles to make sure the engine of the vehicle works precisely as filtering foreign substances in the air such as dust and sands. The entire components including scavenge fan which is one of the important inner part of the air cleaning unit are developed so that we can produce it domestically and don't need to import it from P^⁎⁎ Co., the original maker in United Kingdom. This paper introduces a few verification processes including cleaning efficiency and reliability. As this core unit has developed successfully the improvement of military strength and logistics support can be expected. And design capability, manufacturing skills, maintenance ability of tracked weapon system will be increased thanks to the accumulated technical knowledge obtained from this developing project. Foreign currency savings and reducing operational cost can be expected as well in military industry.

• 한국대기환경학회지
• /
• 제34권2호
• /
• pp.356-365
• /
• 2018

While social networks have become very popular and powerful way of connecting people and sharing new information, they also effectively spread wrong or biased information to the public. We examine the so-called "Shandong peninsular rumor" that claims Chinese government is responsible for the increased air pollution in South Korea and Japan, by moving pollution-causing industries near Beijing to the Shandong peninsular which is close to South Korea. We demonstrate that the amounts of $NO_x$ and $SO_2$ emissions inferred by space-borne monitoring and regional air quality models show clear declining trends in past several years. We do not have any evidences to support the relation of Shandong peninsular emissions change to South Korean air quality.

• 한국항공운항학회지
• /
• 제22권4호
• /
• pp.1-7
• /
• 2014

The purpose of study is to investigate the current user interface level of air traffic control system with the usability analysis and satisfaction survey questionnaire on user satisfaction. Think aloud protocol is used to identify not only task analysis, but also the level of user-friendliness of the FIMS and ASDE system, and the user interface questionnaires was conducted by QUIS. We collected data from 6 controllers for Think aloud protocol and 15 controllers for QUIS in Incheon airport. The results showed that the system was the valuable tool for ensuring human performance with the support of memory and the facilitation of decision-making tasks. It helps air traffic controllers perform better and minimize errors in a congested time. The human-computer interface system design, however, was not applied, which led to the increase of workload. Air traffic controller participation in software development provided excellent examples for applications in terms of software in FIMS. Based on these results, the study provided that the usability of system interface was necessary to take into account human factors. The development and design of system was discussed in User Interface environment.