• 제어로봇시스템학회논문지
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• 제18권9호
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• pp.854-862
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• 2012

The optimal design of batch-storage network by using periodic square wave model provides analytical lot sizing equations for a complex supply chain network characterized as multi-supplier, multi-product, multi-stage, non-serial, multi-customer, cyclic system including recycling and/or remanufacturing. The network structure includes multiple currency flows as well as material flows. The processes are represented by multiple feedstock/product materials with fixed composition which are very suitable for production processes. In this study, transportation processes that carry multiple materials with unknown composition are added and the time frame is changed from single period into multiple periods in order to represent nonperiodic parameter variations. The objective function of the optimization involves minimizing the opportunity costs of annualized capital investments and currency/material inventories minus the benefit to stockholders in the numeraire currency. The expressions for the Kuhn-Tucker conditions of the optimization problem are reduced to a multiperiod subproblem for average flow rates and analytical lot-sizing equations. The multiperiod lot sizing equations are different from single period ones. The effects of corporate income taxes, interest rates and exchange rates are incorporated.

• 한국산업융합학회 논문집
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• 제24권5호
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• pp.537-546
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• 2021

Remanufacturing is one of the most important resource recycling technology in response to resource depletion and environmental pollution. Domestic remanufacturing industry don't invigorate compared to other advanced countries because of low price and reliability of remanufactured product. In this study, remanufactured hydraulic pump and solenoid valve were evaluated durability by accelerated life test. In order that standard remanufacturing process was developed by core analysis and failure mode and effect analysis. And cores were remanufactured by standard remanufacturing process. For accelerated life test, the evaluation item and criteria were deduced by results of FMEA, reliability standards and enterprise interior criteria. To evaluate durability of remanufactured product, the remanufactured hydraulic pump and solenoid valve were evaluated performance after accelerated life test and the results were satisfied with criteria. This study showed that remanufactured products have a similar level of durability to new products by definition of remanufacturing.

• 방사성폐기물학회지
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• 제17권3호
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• pp.279-298
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• 2019

사용후핵연료의 효율적 관리를 위하여 한국원자력연구원에서 수행 중인 파이로 공정으로부터 발생되는 폐기물 처리기술에 대한 최근 연구동향을 종합적으로 고찰하였다. 파이로 폐기물 처리기술은 처분 대상 폐기물의 감용 및 포장, 저장과 최종 처분에 적합한 고화체 제조를 목표로 하고 있다. 한국원자력연구원에서 수행 중인 파이로 폐기물 처리 기술개발 접근 방향은 공정 흐름으로부터 발생한 폐기물내 주요 핵종들을 분리하고 회수한 물질 등을 재사용함으로서 폐기물 발생량을 최소로 하며 동시에 분리한 핵종을 별도로 고화처리하는 것이다. 폐기물 처리 주요 기술 특성은 먼저 전해환원용 원료물질 제조를 위하여 전처리 고온 열처리 공정을 사용하며, LiCl 과 LiCl-KCl 염으로부터 핵종을 분리하고 회수염의 재사용 및 핵종 함유량을 증대시킨 최종 고화체 제조 기술을 개발하는 것이다. 따라서 실험실 규모 실험 결과를 토대로 최근에는 공정 용량 증대를 위한 자료 확보를 목적으로 공학규모 시험을 수행 중에 있다.

• 청정기술
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• 제28권1호
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• pp.32-37
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• 2022

Food waste is produced from food factories, food services, and home kitchens. The generated mass reached 5.4 million tons/year in 2020. The basic management technology for such waste has been biological degradation under an anaerobic environment. However, the whole process is intrinsically slow and considerably affected by the inner physicochemical properties of the waste and other surrounding conditions, which makes optimization of the process difficult. The most promising options to counter this massive generation of waste are eco-friendly treatments or recycling. As a preliminary step for these options, attempts were made to evaluate the feasibility and usability of three simulative models based on reaction kinetics. Model (A) predicted relative changes over reaction time for reactant, intermediate, and product. Overall, an increased reaction rate produced less intermediate and more product, thereby leading to a shorter total reaction time. Particle diminishing model (B) predicted reduction of the total waste mass. The smaller particles diminished faster along with the dominant effect of microbial reaction. In Model (C), long-chain cellulose was predicted to transform into reducing sugar. At a standard condition, 48% of cellulose molecules having 10⁵ repeating units turned into reducing sugar after 100 h. Also it was found that the optimal enzyme concentration where the highest amount of remnant sugar was harvested was 1 mg L^-1.

• 자원리싸이클링
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• 제32권2호
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• pp.43-51
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• 2023

본 연구에서는 자동차엔진의 신품제조시와 재제조시 발생하는 환경영향을 전과정 관점에서 산정하고 이를 기반으로 온실가스 저감효과를 산정하였다. 자동차엔진 원부자재 원료취득 및 제조공정에서 배출되는 온실가스량은 신품제조시 약 3,473 kg, 재제조시 약 872 kg으로 재제조를 통해 저감되는 온실가스량은 약 2,601kg으로 나타나 폐기 단계를 제외한 전과정 측면에서 저감효과가 있는 것으로 분석되었다. LCA 가중화 분석 결과 신품 제조시 환경영향은 1.07E+03 Eco-point, 재제조시 2.67E+02 Eco-point로 나타났으며, 주요 6대 영향 범주 중 지구온난화 점유비율이 99.72%, 99.68%로 높게 나타났다.

• 한국건설순환자원학회논문집
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• 제2권2호
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• pp.158-165
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• 2014

연구에서는 BP부산물을 혼입한 알칼리활성 무시멘트 지반개량재의 사면안정 및 침투류 수치해석을 통하여 원지반토와 비교하여 개량토의 지반개량 효과를 검토하고자 하였다. 그 결과 사면안정해석을 실시한 결과에서는 건기시, 우기시 모두 건설공사 비탈면 설계기준(국토해양부, 2006)의 기준안전율을 만족하는 것으로 확인되었으며, 우기시 쏘일네일링으로 기준안전율을 만족하지 못하는 사면이 개량토로 보강하여 기준치를 만족한 것으로 나타났다. 또한 침투류 해석을 실시한 결과 개량토의 투수계수가 작아지는 것으로 나타났으며, 원지반토에 비하여 개량토로 표면보강된 경우는 포화심도가 낮아진 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.537-540
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• 2004

Recently, for industrial development period, concrete structures in domestics have been increased. They were deteriorated by attack of carbonation, freeze-thaw and corrosion etc. In hence they were demolished and reconstructed, resulted in waste concrete particles. In this paper, waste concrete particles (WCP) by product from different crushing and selecting process were used in soil cement-based pavement in the various recycling. For using WCP in soil cement-based pavement, the Qualities, physical and chemical properties, of WCP should be researched. In the first step, the specified compressive strength of mortar for two types of clay sand soil and clay soil respectively was experimented to be 15 Mpa and then optimum mixing ratio of chemical solidification agent were decided in the range of $1.5\~3.0\%$ in the replacement with cement weight content. In the second step, based on the prior experimental results, recycling possibility of WCP in soil cement-based pavement was studied. In the result of experiment the mixing ratio of WCP were 5, 10, 15 and $20\%$ in the replacement with soil weight and the compressive strength of mortar was somewhat decreased according to the increase of the mixing ratio of WCP.

• 한국환경과학회지
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• 제22권8호
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• pp.1063-1072
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• 2013

To overcome the ecosystem-crisis of resource depletion and climate change, we should maintain and develop a 'Sustainability' of our society. 'After-market' is defined like this : any market where customers who buy one product or service are likely to buy a related follow-on product. This is related to a automotive, electric and electronic, and remanufacturing industry. 'After-market' will be helpful for reuse and recycling of resources aspects, cost and economic efficiency, low-carbon, climate protection, and new industries and job creation effects, To promote 'After-Market', we need to guarantee the quality of products. In this regard, we refer and introduce a new standard, for example, BS8887, PAS141 and ISO20245 etc. In order to promote 'After-Market', first of all, product quality assurance and safety must be demonstrated in the process of reuse. Second, many aspects of a device that protects the rights of consumers to be provided. And third, the related laws and standards should be reviewed. Finally, original manufacturer's awareness for environmental protection and resource conservation and government's institutional support are needed.

• 자원리싸이클링
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• 제33권4호
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• pp.47-61
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• 2024

전기로 제강분진(EAFD : Electric Arc Furnace Dust) 중에 다량 함유되어있는 아연을 회수하기 위한 재활용 기술로서, 현재 세계적으로 가장 많이 상용화된 기술은 Wealz Kiln Process이다. Wealz Kiln Process에서는, 제강분진 중의 Zn, Pb 등과 같은 성분들을 고온의 Kiln에서 환원/휘발(흡열반응)시킨 후에 다시 기체상에서 재산화(발열반응)시켜 후단에 설치된 Bag Filter에서 조산화아연(60wt%Zn)의 형태로 회수하는 프로세스이다. 본 연구에서는, 상업용 규모의 대형 kiln의 재활용 공정에 실제로 적용하기 위한 최적의 공정변수 값을 조사하기 위해서, 실험용 Wealz kiln을 제작하였다. 그리고, 전기로 제강분진과 환원제, 석회석을 혼합한 Pellet을 연속적으로 Kiln에 장입하면서, 조산화아연 회수율을 얻기 위한 최적의 장입량과 가열온도, 체류시간 등을 조사하였다. 또한 Pellet의 최적의 제조조건( Drum 경사각, 수분의 첨가량, 혼합시간 등)도 조사하였다. 또한, SiO₂-CaO-FeO 3성분계 상태도를 참고하여, Pellet의 염기도(basicity)의 변화에 따른 Kiln 내부에서의 저융점 화합물의 생성거동과 Kiln내벽에 시공된 Castable과의 반응성(부착성)을 평가하여 보았다. 그리고, 환원제인 Coke의 대체제로서 무연탄의 사용 가능성을 실질적으로 평가하기 위하여, 무연탄의 첨가량 증가에 따라서 산화/환원반응이 일어나는 Kiln 내부의 온도분포변화, 조산화아연의 품위, 무연탄 중의 타르(Tar)의 거동에 대해서도 조사하였다.

• Environmental Engineering Research
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• 제24권1호
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• pp.99-106
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• 2019

Using the abandoned agricultural by-product corncobs, the most commonly used methylene blue (MB) dyestuffs were removed. This experiment is very meaningful because it is the recycling of resources and the use of environmentally friendly adsorbents. According to the Hauser ratio and porosity analysis, the corncob has a good flow ability of the adsorbent material and many pores, which is very advantageous for MB adsorption. As a result of the experiment, MB concentration of less than 0.005 g/L was very efficiently removed with 10 g/L of bioadsorbent corncob and the maximum adsorption capacity of corncob for MB dyes was obtained at 417.1 mg/g. In addition, adsorption process of MB onto corncob was a physical process according to adsorption energy analysis. Corncob can efficiently and environmentally remove MB in aqueous solution, and is very cost effective and can recycle the abandoned resources.