• 펄프종이기술
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• 제47권2호
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• pp.34-41
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• 2015

Recovered paper has been widely used as a main raw material of papermaking in Korea. Recycling of recovered paper helps to reduce production cost and preserve an environment. To recycle recovered paper efficiently, de-inking is a key process in recycling mills. De-inking process would be affected by various influencing factors such as the type of de-inking agent, mixed ratio of recovered paper, season, and process conditions. In this study, fatty acid and nonionic surfactant were used as the de-inking agent in froth-flotation process of mixed recovered paper. De-inking properties of mixed recovered paper were investigated according to the addition level of each chemical. Nonionic surfactant had a small effect on de-inking efficiency of mixed recovered paper due to decreased reject. As the additional level of fatty acid increases, fragmented ink particles increased and then optical properties of recycled paper decreased because fragmented ink particles adsorbed onto the fiber surface.

• 펄프종이기술
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• 제47권4호
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• pp.88-95
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• 2015

The main sources of recovered paper for newsprint are old newsprint (ONP) and old magazine (OMG). Recently, a lot of advertisement flyers are flowing into bales of ONP and portion of OMG is increasing in recovered paper because the consumption level of coated paper increases. In this study, nonionic surfactant and fatty acid were used as the de-inking agent for froth-flotation process of mixed recovered paper to investigate the effect of increased mixing ratio of OMG. De-inking efficiency of nonionic surfactant decreased as the mixing ratio of OMG increased; ink removal efficiency of froth-flotation is poor, however, the reject ratio increases due to ash from OMG. In comparison with nonionic surfactant, the ash from OMG had a little effect on reject ratio and optical properties of fatty acid applied flotation accept. If nonionic surfactant and fatty acid are added to pulper and flotation cell sequentially, excessive ash from OMG may not give an adverse effect on de-inking efficiency of mixed recovered paper.

• 펄프종이기술
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• 제46권3호
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• pp.28-36
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• 2014

The kind and the mixing ratio of recovered papers would affect the quality of final recycled paper. In this study, effects of the mixing ratio of various domestic recycled papers (old news print (ONP), old corrugated container (OCC) and coated paper (CP)) on variations in physical properties of paper and its productivity were investigated. When the mixing ratio of CP grade increased, the freeness (CSF) of recycled pulp was increased while paper strength and white water turbidity was decreased. Paper strength was decreased as the percentage of OCC was higher than ONP. When ONP was mixed with OCC, no adverse effect was observed except the increased drainage resistance. It is expected that these results could be utilized as fundamental data to establish regulations for the recovered paper grades according to mixing ratios of different kinds of them.

• 한국응용과학기술학회지
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• 제33권2호
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• pp.239-246
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• 2016

본 연구에서는 건축폐기물로 분류되는 레미콘회수수를 재활용함과 동시에 지구온난화의 주범인 $CO_2$의 자원화를 위한 시스템의 공정최적화를 진행하였다. 레미콘회수수를 이용한 액상탄산화 반응에서 가장 중요한 공정은 $Ca^{2+}$를 용출하는 공정이다. 일정량의 레미콘회수수를 이용해 고순도의 $CaCO_3$을 생성하기 위해 $Ca^{2+}$ 용출시 질산에 의해 낮아지는 pH 농도를 기준으로 실험을 진행하였으며, $CO_2$는 발전기 배기가스를 이용해 MEA용액에 포집하였다. 본 연구를 통해 1톤의 레미콘회수수에서 최대 11 kg의 $CaCO_3$를 합성할 수 있었다. 생성된 $CaCO_3$ 분석결과 제지용으로 사용 가능한 것을 확인하였다.

• 대한인간공학회지
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• 제6권1호
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• pp.25-32
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• 1987

The paesent paper deals with obtaining the properly mixed application critaeia for the manual mode, using computer graphic simulation, in order to recover the error effectively occurring in the advanced teleoperator work of man-robot system. In these experiments the error which is occurred during performing the automatic mode is recovered by the manual mode which is combined properly the operation by hyman with the operation by control program. The result shows an improvement availibility of the system by not only establishing an efficient combination of the manual mode according to trajectory planning but also recovering the error effectively. Therefore we suggest that the operation by control program should be applied in macro motion of control and the operation by human in micro motion of control.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.1185-1188
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• 2003

This paper describes a design for a 2.5Gb/s serial data link CMOS transceiver based on the InfiniBand$^{TM}$ specification. The transceiver chip integrates data serializer, line driver, Tx PLL, deserializer, clock recovery, and lock detector. The designed transceiver is fabricated in a 0.25 ${\mu}{\textrm}{m}$ CMOS mixed-signal, 1-poly, 5-metal process. The first version chip occupies a 3.0mm x 3.3mm area and consumes 450mW with 2.5V supply. In 2.5 Gbps, the output jitter of transmitter measured at the point over a 1.2m, 50Ω coaxial cable is 8.811ps(rms), 68ps(p-p). In the receiver, VCO jitter is 18.5ps(rms), 130ps(p-p), the recovered data are found equivalent to the transmitted data as expected. In the design for second version chip, the proposed clock and data recovery circuit using linear phase detector can reduce jitter in the VCO of PLL.L.

• 한국전산구조공학회논문집
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• 제28권2호
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• pp.123-130
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• 2015

본 논문에서는 전자기파에 대한 수치적 파동흡수 경계모델인 Perfectly-Matched-Layer(PML)를 개발하고 PML을 연동시킨 유한요소법에 의해 콘크리트 구조물을 통과하는 마이크로파의 전파거동을 해석하는 수치적 기법을 제시한다. 콘크리트 부재와 공기로 구성된 무한매질을 PML을 경계로 하는 유한영역으로 치환하고, 이 유한영역에서 평면 전자기파에 대한 시간 영역 맥스웰방정식의 수치 해를 혼합유한요소법에 의해 계산하였다. 공기로만 이루어진 균일매질의 경우와 콘크리트 구조물이 존재하는 비균일 매질의 경우에 대하여 단일주파수 및 복합주파수를 갖는 마이크로파의 전기장을 계산하였고, 오차분석을 위해 $L^2$-놈 형태로 표현되는 정해와 수치 해의 상대오차를 정의하여 수치 해의 정확도를 평가하였다. 이 연구는 마이크로파를 이용한 철근콘크리트 구조물의 건전도평가 및 손상평가에 적용될 수 있다.

• Industrial Engineering and Management Systems
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• 제12권2호
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• pp.74-84
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• 2013

Modern companies have been facing devastating impacts from unexpected events such as demand uncertainties, natural disasters, and terrorist attacks due to the increasing global supply chain complexity. This paper proposes a multi stage logistic network model under disruption risk. To formulate the problem practically, we consider the effect of continuity rate, which is defined as a percentage of ability of the facility to provide backup allocation to customers in the abnormal situation and affect the investments and operational costs. Then we vary the fixed charge for opening facilities and the operational cost according to the continuity rate. The operational level of the company decreases below the normal condition when disruption occurs. The backup source after the disrup-tion is recovered not only as soon as possible, but also as much as possible. This is a concept of the business continuity plan to reduce the recovery time objective such a continuity rate will affect the investments and op-erational costs. Through numerical experiments, we have shown the proposed idea is capable of designing a resilient logistic network available for business continuity management/plan.

• Journal of Biosystems Engineering
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• 제35권2호
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• pp.91-99
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• 2010

A Model of small scale total mixed rations(TMR) plant which can be utilized round bales was developed, tested and analyzed in this study. This study consist of two parts. One is development of a small scale TMR plant model which was already reported at the previous paper. This is the second part of the study. For the study, a series of tests of the model plant were performed and its costs was analyzed. Also, the break-even point of the model plant by comparing with market price of commercial TMR feed was determined. Results of the research are summarized as follows ; As the results of mixing test, the average coefficient of variation(CV) value for mixing of the feed was 13.0 % at the gate of the mixer. The production cost was estimated as 8,298 won/head for dairy cattle farm and 2,495 won/head for beef cattle farm, when producing 8 batch a day. Also, it is recommended to utilize the model plant when farm size is over 79 heads for dairy cattle farm and 113 heads for beef cattle farm. As an overall conclusion, the model plant designed for farm size TMR feed mill will be very useful model for both beef cattle and dairy farms in Korea. Also it is expected that the capital investment for the model plant can be recovered with 8 months compare with purchasing commercial TMR feed if the model plant feeds 1,000 beef cattle approximately.