• 설비공학논문집
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• 제24권4호
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• pp.297-305
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• 2012

In recent large-scale semiconductor manufacturing clean rooms, the energy consumption of outdoor air conditioning systems to heat, humidify, cool and dehumidify incoming outdoor air represents about 45% of the total air conditioning load required to maintain a clean room environment. Therefore, the energy performance evaluation and analysis of outdoor air conditioning systems is useful for reducing the outdoor air conditioning load for a clean room. In the present study, an experiment was conducted to compare the energy consumption of outdoor air conditioning systems with a simple air washer, an exhaust air heat recovery type air washer and a DCC return water heat recovery type air washer. It was shown from the present lab-scale experiment with an outdoor air flow of 1,000 $m^3/h$ that the exhaust air heat recovery type and DCC return water heat recovery type air washer outdoor air conditioning systems were more energy-efficient for the summer and winter operations than the simple air washer outdoor air conditioning system and furthermore, the DCC return water heat recovery type one was the most energy-efficient in the winter operation.

• Corrosion Science and Technology
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• 제20권1호
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• pp.26-36
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• 2021

Pipes operating in the seawater environment faces cavitation degradation and corrosion of the metallic component, as well as a negative synergistic effect. Cavitation degradation shows the mechanism by which materials deteriorate by causing rapid change of pressure or high-frequency vibration in the solution, and introducing the formation and explosion of bubbles. In order to rate the cavitation resistance of materials, constant conditions have been used. However, while a dynamic cavitation condition can be generated in a real system, there has been little reported on the effect of ultrasonic amplitude on the cavitation resistance and mechanism of composites. In this work, 3 kinds of epoxy coatings were used, and the cavitation resistance of the epoxy coatings was evaluated in 3.5% NaCl at 15 ℃ using an indirect ultrasonic cavitation method. Eleven kinds of mechanical properties were obtained, namely compressive strength, flexural strength and modulus, tensile strength and elongation, Shore D hardness, water absorptivity, impact test, wear test for coating only and pull-off strength for epoxy coating/carbon steel or epoxy coating/rubber/carbon steel. The cavitation erosion mechanism of epoxy coatings was discussed on the basis of the mechanical properties and the effect of ultrasonic amplitude on the degradation of coatings.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2007년도 추계학술발표회
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• pp.43-49
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• 2007

Al, Ag, Au, Cu, Cd, Co, Fe, Ni, Ph, Zn 등과 밀접한 금속은 일반적인 원소이며, 지속적인 오염물질에 속한다. 금속은 생명체의 생리활동에 필수원소인 경우도 있으나 경우도 있으나 그 중의 일부는 정해진 한계값을 초과할 때에는 독성을 가진다. 자연수 중의 미량금속 측정은 정확도와 정밀도에 있어서 큰 오차를 가지고 있음이 장기간 인식되어 왔다. 미국과 유럽에서는 1975 년 이후 미량금속의 해수 중 농도가 과거에 인지된 농도보다 $1/10{\sim}1/1,000$ 정도 낮아졌으며, 수직 분포는 알려진 생물, 물리, 지화학적인 과정들과 일치하고 있음이 밝혀졌다. 이와 같은 결과는 대부분 미량원소에 대한 분석방법과 기기의 발전에 기인하며, 시료 채취, 보관 및 분석 과정에 발생할 수 있는 오염을 제거해야 하는 세심한 주의 요구되어 진다.

• International Journal of Automotive Technology
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• 제4권2호
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• pp.77-86
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• 2003

How to compare the environmental damage caused by vehicles with different foe]s and drive trains\ulcorner This paper describes a methodology to assess the environmental impact of vehicles, using different approaches, and evaluating their benefits and limitations. Rating systems are analysed as tools to compare the environmental impact of vehicles, allowing decision makers to dedicate their financial and non-financial policies and support measures in function of the ecological damage. The paper is based on the "Clean Vehicles" research project, commissioned by the Brussels Capital Region via the BIM-IBGE (Brussels Institute for the Conservation of the Environment) (Van Mierlo et at., 2001). The VriJe Universiteit Brussel (ETEC) and the universite Libre do Bruxelles (CEESE) have jointly carried out the workprogramme. The most important results of this project are illustrated in this paper. First an overview of environmental, economical and technical characteristics of the different alternative fuels and drive trains is given. Afterward the basic principles to identify the environmental impact of cars are described. An outline of the considered emissions and their environmental impact leads to the definition of the calculation method, named Ecoscore. A rather simple and pragmatic approach would be stating that all alternative fuelled vehicles (LPG, CNG, EV, HEV, etc.) can be considered as ′clean′. Another basic approach is considering as ′clean′ all vehicles satisfying a stringent omission regulation like EURO IV or EEV. Such approaches however don′t tell anything about the real environmental damage of the vehicles. In the paper we describe "how should the environmental impact of vehicles be defined\ulcorner", including parameters affecting the emissions of vehicles and their influence on human beings and on the environment and "how could it be defined \ulcorner", taking into account the availability of accurate and reliable data. We take into account different damages (acid rain, photochemical air pollution, global warming. noise, etc.) and their impacts on several receptors like human beings (e.g., cancer, respiratory diseases, etc), ecosystems, or buildings. The presented methodology is based on a kind of Life Cycle Assessment (LCA) in which the contribution of all emissions to a certain damage are considered (e.g. using Exposure-Response damage function). The emissions will include oil extraction, transportation refinery, electricity production, distribution, (Well-to-Wheel approach), as well as the emission due to the production, use and dismantling of the vehicle (Cradle-to-Grave approach). The different damages will be normalized to be able to make a comparison. Hence a reference value (determined by the reference vehicle chosen) will be defined as a target value (the normalized value will thus measure a kind of Distance to Target). The contribution of the different normalized damages to a single value "Ecoscore" will be based on a panel weighting method. Some examples of the calculation of the Ecoscore for different alternative fuels and drive trains will be calculated as an illustration of the methodology.

• 한국철도학회논문집
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• 제11권3호
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• pp.211-215
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• 2008

전동차는 다양한 물질로 제작된 부품들을 조립하여 완성한다. 긴 내구연한과 다량의 부품 사용은 전동차의 전과정에 걸쳐 많은 환경부하를 야기한다. 따라서 전동차의 원료취득부터 폐기단계까지의 환경부하를 정량적으로 평가할 수 있는 새로운 툴을 개발하는 것이 필요하다. 본 연구에서는 전동차의 환경부하와 에코효율성을 산출할 수 있는 소프트웨어인 RACE를 개발하였다. RACE는 일반 전과정평가 소프트웨어와는 달리 전동차의 주요 부품 및 물질에 대한 전과정 목록 데이터베이스를 내장하고 있다. 향후 철도분야에서 제조자와 운영자간의 환경적인 의사소통의 도구로써 RACE가 활용될 수 있다. 또한 전동차뿐만 아니라 철도차량의 환경성을 보다 쉽게 평가하기 위해서는 지속작인 RACE의 개선이 이루어져야 할 것이다.

• 환경정책연구
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• 제13권2호
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• pp.65-98
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• 2014

해양환경의 플라스틱은 풍화작용에 의해 매우 작은 크기로 부서지는데, 이를 미세플라스틱이라고 한다. 해수에 오염된 잔류성이 크거나 생물축적성이 있는 유기물질은 미세플라스틱에 잘 흡착되며, 이들 물질이 흡착된 미세플라스틱을 해양생물이 섭취하면 먹이사슬을 통해 점차 생물축적된다. 이는 결국 해양생태계의 건강성을 파괴하고 사람을 포함한 상위포식자에게 피해를 끼친다. 해양 오염물질의 흡착제로서의 역할뿐 아니라, 미세플라스틱 그 자체에서 내분비계 교란물질이 용출되어 해양생물에 피해를 입히기도 한다. 우리나라는 잔류성이나 생물축적성이 큰 물질에 대해서는 화학물질 측면에서 규제하고 있으나, 이는 육상에서의 관리에 국한되어 있다. 만약 이들 물질이 해양생태계로 유입되면, 결국 미세플라스틱 흡착 여부에 의해 그 피해가 증가하게 된다. 이에 해양생태계 내에서의 잔류성 생물축적성 물질의 피해를 저감하기 위해서는 우선 미세플라스틱의 관리가 엄격해야 할 것이다. 이에 미세플라스틱 자체를 유해물질로 지정하여 엄격히 관리하거나, 생분해성 플라스틱 이용 확대, 재활용 및 재사용 촉구, clean-up 프로그램의 확대 등을 통해 해양생태계 내로의 플라스틱 유입을 저감하는 노력이 요구된다.

• 청정기술
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• 제9권2호
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• pp.57-61
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• 2003

금속가공 공정에서 알루미늄 합금소재의 알칼리 에칭 후 표면에 발생한 스머트(Smut) 를 제거하기 위해 무질산 디스머트(Nitric acid-free desmut) 용액을 개발하였다. 과산화수소(2%), 불산(0.5%) 및 황산(10%)을 혼합한 산용액이 NaOH 수용액에 처리한 A16061 및 A15052 규격의 알루미늄 합금 소재에 대한 스머트 제거효과가 5% 질산수용액의 사용할 경우와 유사하게 관찰되었다. 스머트 제거를 위한 혼합 산용액 처리 전 후 소재 표면을 SEM-EPMA 분석을 통해 확인하였다.

• 청정기술
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• 제11권2호
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• pp.83-90
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• 2005

본 연구에서는 크롬 탄닝을 대체할 수 있는 환경친화적인 유제 공정 처리제 (폴리머계, 폴리 페놀계, 폴리 레진계)를 개발하고, 이를 제혁 공정에 적용하여 혁의 물리적 특성에 미치는 영향 및 Cr, total nitrogen, COD, SS 등의 환경영향평가로 제혁 공정의 청정화를 위한 기초 연구를 진행하였다.

• 동력기계공학회지
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• 제13권5호
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• pp.67-75
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• 2009

Recently, the higher capacity waste heat recovery PDC clean ventilation system has a tendency which is increasing due to the excellent energy reduction in factory, big building, and so on. This system was developed to complement the room environment which is deteriorated. However, the researches and technologies about this system were not well studied. Specially, the characteristic for heat exchanger element used to this system were not well known. Therefore, this study was carried out to evaluate the mechanical properties of the heat exchanger element as the core parts compose of this system. From results, tensile strength and elongation of the plate type heat exchanger element had about 10.11~14.32 kgf/$mm^2$ and 8.0~16.2%, respectively.

• Corrosion Science and Technology
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• 제21권3호
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• pp.184-199
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• 2022

Steel was exposed in an atmospheric environment, and atmospheric environmental factors that include chloride, humidity, SO₂, NO₂ etc. induced the corrosion of steel. Corrosivity categories classified by SO₂ and chloride deposition rate were low, but those classified by TOW were high in the Korean Peninsula, and on these environmental categories, the corrosivity of atmospheres classified by corrosion rate in carbon steel was low medium, C2-C3, and medium, C3 for zinc, copper, and aluminum. This work performed the outdoor exposure test for 10 years at 14 areas in Korea and calculated the atmospheric corrosion rate of carbon steel. The atmospheric corrosion behavior of carbon steel is discussed based on the various corrosion factors. When the corrosion product forms on carbon steel by atmospheric corrosion, cracks may also be formed, and through these cracks, the environmental factors can penetrate into the interior of the product, detach some of the corrosion products and finally corrode locally. Thus, the maximum corrosion rate was about 7.3 times greater than the average corrosion rate. The color difference and glossiness of carbon steel by the 10 year-outdoor exposure tests are discussed based on the corrosion rate and the environmental factors.