• 한국융합학회논문지
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• 제11권7호
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• pp.79-87
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• 2020

음식물류 폐기물이 야기하는 환경오염 문제는 오랫동안 사회적인 문제였으나 2013년 런던협약 가입으로 인해 음·폐수 해양배출이 금지되면서 한층 심각해졌다. 최근 정부의 음식물류 폐기물 관련 종합 대책의 실시는 감량 성과와 자원화에 많은 기여를 하였으나 지속적으로 시행되지 못하였고 폐기물의 발생 분야별로 적절하게 대응하는 전략의 부족이 지적되었다. 많은 연구에서는 효과적인 감량 정책 시행을 위해서 무엇보다 시민의 참여가 중요하다고 강조하고 있다. 이 연구는 사용자 경험 분석을 기초로 음식물류 폐기물 처리기를 디자인하여 시민의 참여를 높이는 방안을 제안한다. 이를 위해 선행연구에 대한 다각적인 조사·분석, 표적 집단 인터뷰 및 사용자 여정지도를 포함한 사용자 경험연구를 통하여 디자인 개발 방향을 설정하였다. 연구 결과로 도출된 처리기는 폐기물의 수시 배출이 용이해지며 가정 내에서 음식물류 폐기물 배출 과정이 간단해진다. 또한 사용자와 폐기물이 직접적으로 접촉하는 순간은 처리기에 배출하는 시점으로 제한하여 사용자가 겪었던 부정적인 경험을 최소화함으로써 폐기물 감량을 위한 사용자의 적극적인 참여를 유도하였다.

• 대한기계학회논문집B
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• 제36권7호
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• pp.737-744
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• 2012

차량에 의한 대기오염을 실제 주행 조건에서 시간과 공간에 구애받지 않고 실시간으로 측정하기 위하여 이동형 배출가스 측정장치(MEL)가 제작되었다. 미니밴 차량에 CO, NOx, $CO_2$와 같은 배출가스 측정 장비와 입자의 수농도 및 입경별 개수농도 분포 측정을 위한 FMPS, CPC가 탑재되었다. 차량 전단에 장착되는 흡입 샘플링 포트를 사용하여 여러 종류의 차량 추적 실험을 수행하였다. 본 연구에서는 MEL의 상세 사양 및 이를 이용하여 디젤 및 가솔린 연료를 사용하는 승용차량들을 추적 실험한 결과를 나타내었다. 디젤 차량에서 배출되는 입자의 수농도는 가솔린 차량에서 배출되는 입자의 수농도보다 높았으며 다량의 극미세입자를 포함하고 있었다. 하지만, 직접분사식 가솔린 차량은 DPF가 장착된 디젤 차량에 비하여 50 nm 이상의 입경 영역에서 입자의 농도가 높은 경향을 보였다.

• 한국보육지원학회지
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• 제10권4호
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• pp.5-28
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• 2014

우리나라는 양적으로 확대된 어린이집의 보육서비스 질을 제고하기 위해 2005년 1월 영유아보육법을 개정하면서 보육교사의 자격 기준을 강화하였다. 이후 원장의 국가자격증 도입, 명칭 변경, 원장과 보육교사 자격기준 강화와 보수교육 체계 정비, 보육교사 자격취득 보육관련 교과목 및 학점기준 강화, 2012년에는 보수교육 보육교사자격검정 등 업무위탁관련 조항을 정비하는 등 보육교직원 관련 법적 근거의 변화가 있었다. 이는 보육교직원이 보육의 질 향상과 밀접한 관련이 있으며 영유아에게 직접적인 영향력을 주는 매우 중요한 변인이기 때문이다. 본 연구에서는 보육교직원과 관련된 법적 근거 규정이 계속 강화되고 있는 시점에서 문헌조사와 분석을 통해 보육교직원의 현황과 발전방향을 서술하고자 하였다. 본 연구는 크게 3가지 측면을 다루고 있다. 첫째, 보육교직원 관련 역사적 흐름을 리뷰하고 보육교직원의 개념과 역할, 전문성, 법적지위를 조사 분석하였다. 둘째, 보육교직원의 양성기관, 자격체계, 재직 보육교직원, 처우의 현황을 조사하였다. 셋째, 이 모든 것을 토대로 양성체계, 자격기준, 보수교육과 훈련체계, 처우개선 및 지위 향상을 위한 발전방향을 제안하였다.

• 대한기계학회논문집B
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• 제24권6호
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• pp.785-791
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• 2000

GDI (Gasoline Direct Injection) engines are considered as one of the candidates for next generation engines of passenger cars, which reduce exhaust emissions and fuel consumption. In GOI engines, a high-pressure gasoline supply system is required to directly inject the fuel to combustion chambers. Because of low lubricity of gasoline fuel, the clearance between a plunger and a barrel in GDI fuel pumps is too wide to achieve smooth hydrodynamic lubrication. Thus, it is difficult to generate high-pressure condition in GDI fuel pump since large amount of leakage flow occurs between the plunger and the barrel In this study, an optimum plunger design is presented to minimize leakage in the aspect of flow control. This paper analyzes leakage flow characteristics in the clearance to improve pumping performance of GDI fuel pumps. Effects of groove in the plunger are studied according to variations of depth and width. Evaluations of pumping performance are determined by the amount of pressure drop in the leakage path assuming a constant leakage flows. Both of turbulence and incompressible models are introduced in CFD (Computational Fluid Dynamics) analysis. Design parameters have been introduced to minimize leakage in limited space, and a methodological study on geometrical optimization has been conducted. As results of CFD analysis in various geometrical cases, optimum groove depths have been found to generate maximum sealing effects on gasoline fuel between the plunger and the barrel. This procedure offers a methodological way of an enhancement of plunger design for high-pressure GDI fuel pumps.

• 한국대기환경학회지
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• 제22권4호
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• pp.440-450
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• 2006

PM10, NOx, and $O_3$ were measured at six locations, of which each three is horizontally and vertically distributed respectively, in an apartment complex around the heavily traffic road. Those were measured seven times a day with two hours interval starting from 8 o'clock in the morning for 15 days during May 2005 $\sim$ September 2005. PM10 and NOx showed high concentrations in rush hours while low concentrations in midday due to the direct emissions from automobiles in operation. Temporal variations of 01 showed very much similar trend appeared in normal urban atmospheres. The spatial distributions of PM10, NOx and $O_3$ showed that almost all of concentrations were higher in a row of Roadside > Surface at 130 m apart from the road > Surface at 230 m apart from the road > 3rd floor of apartment building > 15th floor of apartment building > 27th floor of apartment building. Model equations, which can project spatial concentration distributions, were constructed by combining the horizontal and the vertical linear regression equations derived from six mean values corresponding to six measuring locations. According to inter-comparison of PM10, NOx, and $O_3$ with the constructed model equations, concentration gradients were higher in a row of Vertical direction of NOx > Vertical direction of PM10 > Horizontal direction of NOx > Horizontal direction of PMIO > Vertical direction of $O_3$ > Horizontal direction of $O_3$. Why concentration gradient of particulate PM10 is lower than that of gaseous NOx is in question, and should be studied.

• 자원ㆍ환경경제연구
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• 제21권1호
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• pp.157-173
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• 2012

본 논문은 환경기초시설에 대한 투자가 수질을 직접 개선하는 효과와 더불어 결과적으로 수질을 악화시킬 수도 있는 가능성을 제기하였다. 환경기초시설에 대한 투자가 수질에 부정적인 효과를 낳는 이유는 그것이 예산제약하에 있는 규제당국의 선택에 영향을 미치고 결과적으로 피규제 기업의 오염배출량을 증가시켜 수질을 악화시킬 수 있기 때문이다. 본 논문에서는 한국의 경험을 살펴보고 특별히 1991년 이후 환경기초시설의 투자가 과연 4대강의 수질을 개선했는가를 점검하고자 하였다. 우리는 2단계 최소자승법을 사용하여 기초시설의 건설이 단속활동의 감소를 통해 부정적인 효과를 가졌지만 종합적으로 수질개선에 기여했음을 실증적으로 보였다. 본 논문이 갖는 중요한 정책함의는 환경기초시설의 건설이 수질개선에 기여하기 위해서는 그것과 더불어 환경기준을 설정하고 이를 강제하는 단속활동이 적절히 배합되어야 한다는 것이다.

• 한국자동차공학회논문집
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• 제19권5호
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• pp.14-21
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• 2011

In diesel engines, accurate EGR control is important due to its effect on nitrogen oxide and particulate matter emissions. Conventional EGR control system comprises a PI feedback controller for tracking target air mass flow and a feedforward controller for fast response. Physically, the EGR flow is affected by EGR valve lift and thermodynamic properties of the EGR path, such as pressures and temperatures. However, the conventional feedforward control output is indirectly derived from engine operating conditions, such as engine rotational speed and fuel injection quantity. Accordingly, the conventional feedforward control action counteracts the feedback controller in certain operating conditions. In order to improve this disadvantage, in this study, we proposed feedforward EGR control algorithm based on a physical model of the EGR system. The proposed EGR control strategy was validated with a 3.0 liter common rail direct injection diesel engine equipped with a DC motor type EGR valve.

• 한국자동차공학회논문집
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• 제12권6호
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• pp.38-45
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• 2004

This paper studies the effects of intake port configuration on the swirl that is key parameter in the flow field of direct injection diesel engines. In-cylinder flow characteristics is known to have significant effects on fuel air mixing, combustion and emissions. To investigate the swirl flow generated by various intake ports, steady state flow tests were conducted to evaluate the swirl. Helical port geometry, SCV shape and bypass were selected as the design parameters to increase the swirl flow and parametric study was performed to choose the optimal port shape that would generate a high swirl ratio efficiently. The results revealed that a key factor in generating a high swirl ratio was to suitably control the direction of the intake air flow passing through the valve seat. For these purposes, we changed the distance of helical and tangential port as well as installed bypass near the valve seat and the effects of intake port geometry on in-cylinder flow field were visualized by a laser sheet visualization method. From the experimental results, we found that the swirl ratio and mass flow rate had a trade off relation. In addition, the result indicates that the bypass is a effective method to increase the swirl ratio without sacrificing mass flow rate.

• Steel and Composite Structures
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• 제22권3호
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• pp.537-565
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• 2016

Australian railway networks possess a large amount of aging timber components and need to replace them in excess of 280 thousands $m^3$ per year. The relatively high turnover of timber sleepers (crossties in a plain track), bearers (skeleton ties in a turnout), and transoms (bridge cross beams) is responsible for producing greenhouse gas emissions 6 times greater than an equivalent reinforced concrete counterparts. This paper presents an innovative solution for the replacement of aging timber transoms installed on existing railway bridges along with the incorporation of a continuous walkway platform, which is proven to provide environmental, safety and financial benefits. Recent developments for alternative composite materials to replace timber components in railway infrastructure construction and maintenance demonstrate some compatibility issues with track stiffness as well as structural and geometrical track systems. Structural concrete are generally used for new railway bridges where the comparatively thicker and heavier fixed slab track systems can be accommodated. This study firstly demonstrates a novel and resilient alterative by incorporating steel-concrete composite slab theory and combines the capabilities of being precast and modulated, in order to reduce the depth, weight and required installation time relative to conventional concrete direct-fixation track slab systems. Clear benefits of the new steel-concrete composites are the maintainability and constructability, especially for existing railway bridges (or brown fields). Critical considerations in the design and finite element modelling for performance benchmarking of composite structures and their failure modes are highlighted in this paper, altogether with risks, compatibilities and compliances.

• 한국기후변화학회지
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• 제5권4호
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• pp.331-338
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• 2014

The continued efforts to reduce GHG emission by international cooperation and each country are in progress. As part of these efforts, Korea's ETS is enforced in 2015. This was the time to make strategies for each company to respond Korea's ETS. This study was performed to suggest a draft of basic strategies for electronic component industry in current Korea's ETS stage are as follows; - Analyzing the nature of electronic component industry - Identifying needs for corresponding ETS of electronic component industry - Analyzing basic countermeasures for each stage of ETS - Suggesting drafts of basic strategies for electronic component industry in current Korea's ETS stage The result of this study, the current stage of Korea's ETS is moving from implementation of the scheme become determined and prepare the minimum corresponding to direct corresponding to the regulation and market change. Electronic component industry has many GHG emission growth(or change) factor, and it will be make electronic component industry as a buyer when Korea's ETS is enforced. Korea's ETS will be clearly act as a regulation rather than new business for electronic component industry. Therefore, identifying the Korea's ETS as a regulation is resonable strategy for corresponding the scheme. The basic strategies of electronic component industry th responding Korea's ETS are as follows; - Building internal organization and decision-making system before enforcement the Korea's ETS - Establishing internal basic corresponding strategies according to carbon price forecast scenarios - Considering the energy consumption and GHG emissions in design phase and preparing the global ETS market in mid or long term.