• 한국환경과학회지
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• 제4권3호
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• pp.153-167
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• 1995

Recycling is receiving increasing social attention today as our nation begins to grapple with the significant problems caused by huge amount of municipal solid waste. The topic of recycling is not simple but extremely complicated. This study attempts to provide basic data and policy options for expanding and improving separated collection and recycling in public residential areas, through three case study of apartment housing areas in Taegu Metropolitan City. The main results of this study are summarized as follows. For the significant period of time, all three case areas had in common the extreme difficulty in establishing and operating the system of connecting public participation, collection and storage, transportation, and actual recycling of materials because of a variety of problems involved in this process. Both amounts of and prices for collected materials fluctuated considerably over time mainly due to monthly changes in recyclable home materials and the dynamic nature of recycling markets. Public questionnaire survey revealed the very high level of participation in separated collection, not only because almost all respondents well understood the necessity and importance of recycling, but because they also knew how to do separated collection. But overall activities were rated low and most respondents suggested the enlargement of public participation, the improvement of collection and storage facilities, and collection transportation networks. In particular, most respondents had little experience of using recycled Products and used mainly reproduced soap and bathroom tissue. Furthermore, they were considerably unsatisfied with low variety and quality of recycled products, their high prices and low availability in the market. Finally potential policy options and activities for improving separated collection and recycling are suggested.

• Safety and Health at Work
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• 제8권3호
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• pp.296-305
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• 2017

Background: Surfactant-containing water sprays are commonly used in coal mines to collect dust. This study investigates the dust collection performance of different surfactant types for a range of coal dust particle sizes and charges. Methods: Bituminous coal dust aerosol was generated in a wind tunnel. The charge of the aerosol was either left unaltered, charge-neutralized with a neutralizer, or positively- or negatively-charged using a diffusion charger after the particles were neutralized. An anionic, cationic, or nonionic surfactant spray or a plain water spray was used to remove the particles from the air flow. Some particles were captured while passing through spray section, whereas remaining particles were charge-separated using an electrostatic classifier. Particle size and concentration of the charge-separated particles were measured using an aerodynamic particle sizer. Measurements were made with the spray on and off to calculate overall collection efficiencies (integrated across all charge levels) and efficiencies of particles with specific charge levels. Results: The diameter of the tested coal dust aerosol was $0.89{\mu}m{\pm}1.45$ [geometric $mean{\pm}geometric$ standard deviations (SD)]. Respirable particle mass was collected with $75.5{\pm}5.9%$ ($mean{\pm}SD$) efficiency overall. Collection efficiency was correlated with particle size. Surfactant type significantly impacted collection efficiency: charged particle collection by nonionic surfactant sprays was greater than or equal to collection by other sprays, especially for weakly-charged aerosols. Particle charge strength was significantly correlated with collection efficiency. Conclusion: Surfactant type affects charged particle spray collection efficiency. Nonionic surfactant sprays performed well in coal dust capture in many of the tested conditions.

• 한국해양공학회지
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• 제33권1호
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• pp.42-49
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• 2019

Drilling mud was used once in the step of separating the gas and powder they were transported to a surge tank. At that time, the fine powder, such as dust that is not separated from the gas, is included in the gas that was separated from the mud. The fine particles of the powder are collected to increase the density of the powder and prevent air pollution. To remove particles from air or another gas, a cyclone-type separator generally can be used with the principles of vortex separation without using a filter system. In this study, we conducted numerical simulations of air-particle flow consisting of two components in a cyclone separator in a mud handling system to investigate the characteristics of turbulent vortical flow and to evaluate the collection efficiency using the commercial software, STAR-CCM+. First, the single-phase air flow was simulated and validated through the comparison with experiments (Boysan et al., 1983) and other CFD simulation results (Slack et al., 2000). Then, based on one-way coupling simulation for air and powder particles, the multi-phase flow was simulated, and the collection efficiency for various sizes of particles was compared with the experimental and theoretical results.

• 한국입자에어로졸학회지
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• 제16권4호
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• pp.119-130
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• 2020

In this study, we developed a separated two-stage electrostatic precipitator applicable in a subway air conditioning system. We studied the characteristics of collection efficiency of 0.3 ㎛ particle and ozone generation at different charger sizes and gaps of collector plates. Also, we compared the performance of the two-stage ESP to the MERV 10 filter with the removal efficiency of 10% used in actual subway air conditioning system. The maximum collection efficiency of 0.3 ㎛ particle was 93% at A charger (600 mm×250 mm×600 mm) and 84% at B charger (330 mm×280 mm×330 mm). Especially, with voltages applied to chargers with collection efficiency of about 80% or more, the ozone concentration of two different chargers was 5 ppb to 35 ppb. Finally, the filter quality of the collector developed in this study was 400 times higher than that of the MERV 10 filter. Therefore, it was concluded that the two-stage ESP could be a promising PM removal device suitable for subway air conditioning system.

• 산업기술연구
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• 제17권
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• pp.169-174
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• 1997

This investigation was carried out to study on the generation property, management and seperate collection rate of solid waste in the Gu-Gok Falls. Generation rate of solid waste was 80.785kg/day and unit waste generation rates was $65.55g/day{\cdot}tourist$ one person. Physical component of solid waste were garbage 46%, papers 20%, empty bottles 10%, respectively. A plan is required to decrease generation rate of garbage waste. As result to investigate separated garbage can, papers and can were separated more than 60%. But empty bottles and scrap iron were separated less than 50%. P.E.T, steel can, aluminum can and empty bottles were 20% of total generation rate, and profit of reuse is \700,800/year.

• 한국가금학회:학술대회논문집
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• 한국가금학회 2002년도 가을 학술발표논문집
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• pp.98-99
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• 2002

Collection of large number of gonadal Primordial germ cells(gPGCs) is a prerequisite factor for improving germline transmission efficacy in the aves, In this study a magnetic-activated cell sorter(MACS) was applied for improving retrieval efficacy of quail gPGCs and the migration capacity of MACS-separated gPGCs was further examined after being transplanted to recipient embryos. We also induced germline chimeras by transfer of MACS-separated quail gPGCs at the efficiency of 17.4% on average.

• 한국자원식물학회지
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• 제11권1호
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• pp.70-79
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• 1998

This study was conducted to understand the effects of weather and tapping date on yield and quality of lactree(Rhus verniciflua) sap yield showed a significant positive correlation with the minimum temperature of one day before sap collection at 1% level and with theminimum humidity of theday of sap collection at 5% level. However, the differences between the maximum and the minimum temperatures and humidities of the day of sap collection were negatively correlated with the sap yield at 5% level. Multiple regression analysis indicated that the minimum temperature of one day bofore sap collection and the minumum humidity of the day sap collection were important factors for increasing sap yield. The high sap yield of lactree by Japanese tapping method was recorded during mid-July and early August. Seasonal variation in lactree sap constituents was observed. The sap collected on 15th of August contained the highest urushiol content (68.3%) and the lowest water content resulting in high quality of lactree sap. By reversed-phase HPLC analysis, fove urushiol components were separated from each other depending on the number of doulbe bonds in the side-chain , and seaxonal variation of urushiol composition was noticed. The 3-C15 triene content fo the sap collected on 5th of July was the highest(77.56%) indicating the major component of urushiol which affects lactree sap quality.

• 정보관리학회지
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• 제25권3호
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• pp.209-230
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• 2008

본 연구는 빠르게 발전되는 네트워크 환경을 고려한 분산된 자원 활용에 필요한 기반 연구이다. 앞으로의 자원공유에 대한 노력은 기술적인 문제가 아닌 의미져인 상호운용성이 강조되어야 한다. 이를 위해 본 연구에서는 자원공유를 위한 컬렉션 단위 기술(collection level description; 이하 CLD라고 함) 모형을 제안하였다. 먼저 컬렉션의 범위, 구축목적, 관련 행위자들을 기반으로 하여 컬렉션에 대한 정의를 설명하였으며, CLD의 중요성을 강조한 연구와 그와 관련된 표준들을 비교 분석하였다. 마지막으로는 기존의 CLD의 기능에서 보강되어야 할 관계 중심의 모형 구축을 시도하였으며, 이를 위해 온톨로지 개념을 사용하였다. 온톨로지기반 CLD 모형은 새로운 관계를 창출하기 위한 다양한 표현 기술들을 정의하였다. 기존 연구와는 달리 클래스와 속성을 구별하고, 속성 중에서도 클래스 자체에 대한 특성과 클래스들 간의 관계를 연결하는 속성으로 나누어서 제시하였다.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2020년도 춘계학술대회
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• pp.47-47
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• 2020

The Korean National Agrobiodiversity Center holds the more than 1300 accessions of proso millet, but a large portion of accessions are landrace of Korea that has very similar traits. To comprehend the maximum genetic diversity of this crop, a core collection with minimum number of accessions will facilitate easy access to genetic material. Here we assessed the genetic diversity and population structure in a germplasm collection of 830 accessions by employing EST-SSR markers and morphological traits. A total of 107 alleles were detected with an average allele number of 4.9 per locus among the 830 accessions based on 37 EST-SSR markers. The number of alleles per locus ranged from 2 to 7. Polymorphism information content and expected heterozygosity ranged from 0.06 to 0.68 (mean = 0.21) and 0.06 to 0.73 (mean = 0.23), respectively. The germplasm collection was separated into two groups based on population structure analysis, whereas principal coordinate analysis (PCoA) could not cluster accessions according to their geographic origin. Subsequently, a preliminarily developed core collection with a total of 141 accessions (17%) was selected from the whole set of germplasm by combining allelic variations of EST-SSR markers and eight different phenotypic traits. The core collection optimally represented the whole germplasm collection and displayed a similar level of PCoA value and genetic variation from the initial collection. The results obtained here provide a primary resource for further genetic analysis and establish a reference for further development of appropriate genetic breeding strategies.

• 유기물자원화
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• 제9권3호
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• pp.111-118
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• 2001

본 연구의 목적은 음식폐기물의 수거에 소요되는 인력과 장비를 파악할 수 있도록 수거요소를 분석하는데 두었다. 이를 위해 수거단계를 기능단위로 분류하고, 수거요소들은 현장조사를 통하여 분석하였다. 실측결과로부터 단계별 요소들을 산정한 결과, 단독주택 인력시간소요량의 경우 3.3인${\cdot}$시, 단독주택 운반속도의 경우 22.4km/시, 2.5톤 차량의 하차시간 5분 등의 산정이 가능하였다. 인력과 장비에 관한 여건을 동일하게 설정하고 2.5톤의 음식폐기물을 수거하는데 소요되는 지역유형별 수거시간을 산정한 결과, 아파트지역의 경우 1회의 수거에 3.03시간이 소요되었으며, 단독주택지역은 아파트지역보다 3배의 수거시간이 요구되었다. 본 연구에서는 1개 지역만을 대상으로 극히 작은 수거회수에 대해 조사한 결과이므로, 대표성 있는 수거요소들을 산정하려면 많은 후속 연구가 필요하다고 본다.