• 유기물자원화
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• 제1권2호
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• pp.299-315
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• 1993

시민들의 생활폐기물에 대한 재활용활동을 알아보기 위하여 서울시 도봉구, 시흥시, 김포군을 선정하여 발생원별로 그 실태를 조사하였다. 3개 조사지역의 재활용량은 0.02 kg/인/일 -0.10 kg/인/일 범위에 있었으며, 회수율은 폐지가 42.7%로 가장 높고, 빈병, 유리류가 10.7%, 캔류가 14.8%, 플라스틱류가 2.8%로 가장 낮았다. 수집 및 판매되는 재활용품에서는 중량비나 판매금액의 구성비에 있어서 폐지가 60% 이상으로 가장 중요한 품목이었으며, 다음이 빈병류이었다. 재활용품의 판매금액은 주택지역이나 사무지역 모두 5원/인/일 이하로 미미한 액수였다. 시민조직의 일종인 재활용추진협의회의 구성을 보면 대부분이 통 반장 중심의 조직으로 구성되어 있었고 활동은 쓰레기의 재분류작업에 한정되어 있었다. 일반적으로 시민들의 참여도와 회원들의 만족도는 낮았으며 경제적 유인동기가 낮아서 가까스로 명맥을 유지하고 있었다. 이 논문에서는 재활용 활성화방안으로 분리수거지침의 제정, 적정 인구규모별 자생적 주민조직의 활성화, 유휴노동력의 활용, 민간수거업체의 육성에 대하여 검토하였다.

• 펄프종이기술
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• 제42권2호
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• pp.95-101
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• 2010

For the development of higher-sizing performance of paper, a sizing agent using recycled PET was synthesised. Polyester resin was extracted from wasted PET by subcritical hydrolysis and finally modified to synthetic sizing agent by mixing water-disperse PET with triphenyl phosphite(TPP). The modified PET was considered as an internal sizing agent in different wet-end papermaking conditions. The optimum condition in sizing efficiency was obtained in initial pH of 6.5 in case of rosin+alum system, and 7.5 in case of rosin+alum+PET system, respectively, and in addition amount of PET 3%. The sizing efficiency was also closely related according to the fiber properties of wet-end slurry, such as virgin fibres from UKP and recycled fibres from KOCC. The application of modified PET was good in strength improvement of paper, specially in tensile strength.

• 한국포장학회지
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• 제11권1호
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• pp.33-40
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• 2005

This study was carried out for effective utilization of recycling resources to investigate the repulping conditions of car air filter waste paper and to evaluate the application into corrugating medium papermaking by blending these repulped pulps. Car air filter waste paper was made of virgin BKP and it was dipped into phenol resin solution. It was well disintegrated by laboratory Valley beater with 10%(basis on oven-dried pulp weight) NaOH addition and defoamer usage. The optimal temperature, beating consistency and treatment time were mainly $40^{\circ}C$, 1% and $30{\sim}40$ minutes, respectively. Handsheets were prepared with various blending ratios between air filter recycled pulp and KOCC. In the case of $10{\sim}20%$ substitution with air filter recycled pulp, physical properties reductions as compressive strength and burst strength of sheets were lower than others. These results showed more favour than the partial substitution of KOCC for corrugating medium even though some strength reduction of paper. It was also observed that the waste water of air filter recycling was not affective to environmental problems.

• 한국구조물진단유지관리공학회 논문집
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• 제9권4호
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• pp.209-216
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• 2005

본 연구에서는 피로시험을 통해 H형 및 Channel형 복공판의 성능을 검토하였다. 이 시험을 통하여 균열의 발생원인과 구조체의 거동의 상관성을 분석하였다. H형 복공판은 백만회 이상의 반복하중에서도 안정적으로 거동하였다. Channel형 복공판의 경우 시험체 모두 대략 십만회에서 피로파괴가 발생하여 공용하중을 사용하는데 있어 내구 수명의 확보에 문제점이 있음을 알 수 있었다.

• 한국건축시공학회지
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• 제12권1호
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• pp.87-97
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• 2012

This paper presents a method of estimating the setting time of cement mortar incorporating recycled aggregate powder (RP) and cement kiln dust (CKD) at various curing temperatures by applying an equivalent age method. To estimate setting time, the equivalent age using apparent activation energy (Ea) was applied. Increasing RP and CKD leads to a shortened initial and final set. Ea at the initial set and final set obtained by Arrhenius function showed differences in response to mixture type. These were estimated to be from 10~19 KJ/mol in all mixtures, which is smaller than those of conventional mixture ranging from 30~50 KJ/mol. Based on the application of Ea to Freisleben Hansen and Pederson's equivalent age function, equivalent age is nearly constant, regardless of curing temperature and RP contents. This implies that the concept of maturity is applicable in estimating the setting time of concrete containing RP and CKD. A high correlation was observed between estimated setting time and measured setting time. A multiregression model was provided to determine setting time reflecting RP and CKD. Thus, the setting time estimation method studied herein can be applicable to concrete incorporating RP and CKD in the construction field.

• 자원리싸이클링
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• 제28권6호
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• pp.9-17
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• 2019

4차산업 혁명과 에너지 신산업 등의 성장에 따라 희유금속의 사용이 계속하여 증가하고 있으며, 희유금속의 사용 증가에 따라 희유금속의 재활용이 중요해 지고 있다. 본 논문에서는 희유금속 중 하나인 주석 소재의 국내·외 품질 기준 현황과 재활용된 주석의 성능 테스트에 관해 조사하였다. 성능 테스트 결과, 천연자원 주석과 재활용된 주석의 성능 차이는 없는 것으로 분석되었다.

• 한국가구학회지
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• 제26권3호
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• pp.252-261
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• 2015

Unlike traditional cultural assets, industrial assets are closely tied with contemporary life in numerous ways, and have acted as a bridge between the traditional architectural buildings and contemporary architectural buildings, reflecting the overall economical, social and cultural portraits of that time. Reinvestigating them in a new light, granting just and fair values, and preserving and transmitting these modern cultural heritages is a method of preserving the historical and cultural traditions in order to keep own identity and integrity. Nowadays, however, due to various sprawling developments and new development-oriented urban policies, only a select few industrial assets are being protected, the rest facing demolition and damages. In order to better cope with such situation, Korea has officially introduced the Registered Cultural Properties System since 2001, and began acknowledging the historical values of industrial buildings as modern cultural properties. By systematic analysis and deduction of characteristics from successfully recycled precedents such Oberhausen Gasometer in the state of Nordhein-Westfalen that have been preserved and recycled as cultural spaces, this paper aims to find and propose suggestions to rehabilitate and recycle the industrial cultural properties in Korea.

• Structural Engineering and Mechanics
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• 제62권3호
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• pp.357-364
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• 2017

This paper presents the results of a study that investigated the improvement of the mechanical properties of coarse and fine recycled asphalt pavement (RAP) produced by adding silica fume (SF) with contents of 5%, 10%, and 15% by total weight of the cement. The coarse and fine natural aggregate (NA) were replaced by RAP with replacement ratio of 20%, 40% and 60% by the total weight of NA. In addition, SF was added to NA concrete mixes as a control for comparison. Twenty eight mixes were produced and tested for compressive, splitting tensile and flexural strength at the age of 28 days. The results show that the mechanical properties decrease with as the content of RAP increases. And the decrease in the compressive strength was more in the fine RAP mixes compared to the coarse RAP mixes, while the decrease in the splitting tensile and flexural strength was almost the same in both mixes. Furthermore, using SF enhances the mechanical properties of RAP mixes where the optimum content of SF was found to be 10%, and the mechanical properties enhancement of coarse RAP were better than fine RAP mixes. Accordingly, the RAP has the potential to be used in the concrete pavements or in other low strength construction applications in order to reduce the negative impact of RAP on the environment and human health.

• Computers and Concrete
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• 제24권1호
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• pp.19-35
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• 2019

In this paper, the effect of the type and amount of fibers on the physicomechanical properties of concrete containing fine recycled refractory brick (RRB) and natural aggregate subjected to elevated temperatures was investigated. For this purpose, forta-ferro (FF), polypropylene (PP), and polyvinyl alcohol (PVA) fibers with the volume fractions of 0, 0.25, and 0.5%, as well as steel fibers with the volume fractions of 0, 0.75, and 1.5% were used in the concrete containing RRB fine aggregate replacing natural sand by 0 and 100%. In total, 162 concrete specimens from 18 different mix designs were prepared and tested in the temperature groups of 23, 400, and $800^{\circ}C$. After experiencing heat, the concrete properties including the compressive strength, ultrasonic pulse velocity (UPV), weight loss, and surface appearance were evaluated and compared with the corresponding results of the reference (unheated) specimens. The results show that using RRB fine aggregate replacing natural fine aggregate by 100% led to an increase in the concrete compressive strength in almost all the mixes, and only in the PVA-containing mixes a decrease in strength was observed. Furthermore, UPV values at $800^{\circ}C$ for all the concrete mixes containing RRB fine aggregate were above those of the natural aggregate concrete specimens. Finally, regarding the compressive strength and UPV results, steel fibers demonstrated a better performance relative to other fiber types.

• 자원리싸이클링
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• 제30권1호
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• pp.26-34
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• 2021

타이타늄은 구조용 금속 중 알루미늄, 철, 마그네슘에 이어서 네 번째로 풍부한 금속이지만, 금속으로의 제련이 어려워 희소금속으로 분류되고 있다. 특히 타이타늄의 제련공정은 에너지 다소비형 공정이다. 타이타늄 스크랩으로 잉곳을 제조하면 에너지 소비량과 CO2 발생량을 약 95 %까지 절감할 수 있다. 그러나 스크랩 중의 철분과 산소 등의 불순물을 제거하기 어려워 리사이클링 되는 양은 한정되어 있다. 일반적으로 고품위 타이타늄 스크랩은 순타이타늄 스펀지의 재용해 공정에 투입하여 희석하고, 저품위 스크랩은 페로타이타늄 제조용 원료로 사용되고 있다. 본 논문에서는 이러한 타이타늄의 리사이클링 기술을 이해하기 위해 타아타늄의 제련기술과 리사이클링 기술에 대하여 고찰하였다.