• Environmental Engineering Research
• /
• 제16권2호
• /
• pp.103-109
• /
• 2011

This work experimentally determined the effect of thermal and microwave pretreatments on the anaerobic digestion of mixtures of municipal primary and secondary sludges in semi-continuous mesophilic digesters at hydraulic retention times (HRT) of 20, 15, 10, 7, and 5 days. The ratio of soluble chemical oxygen demand (COD) to total COD in thermally pretreated and microwaved sludges at $80^{\circ}C$ was 2.7 and 3.2 times higher than that of raw sludge, respectively. The volatile solids (VS) and COD removal efficiencies in all three digesters fed with raw (control), thermally pretreated (TM), and microwaved (MW) sludges decreased as the HRT was reduced. The highest relative improvement in VS removal compared to the control occurred at the HRT of 5 days in the TM and MW (29 and 41% higher than the control, respectively). At this HRT, improvement in the COD removal efficiencies in the TM and MW compared to the control was 28 and 53%, respectively. Improvements in biogas production compared with the control increased in both the TM and MW as the HRT was reduced to 5 days. The relative improvement in daily biogas production compared to the control from the TM and MW was 33 and 53% higher than the control at the HRT of 5 days, respectively. The results show that microwave pretreatment is more effective than thermal pretreatment in increasing the solubilization degree and mesophilic anaerobic biodegradability of sewage sludge.

• 한국유기농업학회지
• /
• 제12권2호
• /
• pp.209-217
• /
• 2004

The aim of this experiment was to investigate the effects of applying times and dilution rates of cattle slurry on dry matter yields of orchard grass. Cattle slurry was applied at the rates of average mineral nitrogen fertilizer equivalent to 150 kg/ha/year in 3 cutting frequency. Significantly higher dry matter yields than that of no fertilization (3.04 ton DM/ha) were recorded in the application of diluted cattle slurry(5.38~6.25 ton DM/ha) (p<0.05). Especially, this tendency was shown with higher annual dry matter yields at the partitioned dressing times, such as at the applications for 1st and 2nd growth, 1st and 3rd growth, and 1st, 2nd and 3rd growth respectively. The yields of annual dry matter both at fertilizing phosphorus and potassium, and phosphorus, potassium and nitrogen were higher than no fertilization as 5.41 tons and 8.78 tons per ha respectively. However, with application of diluted cattle slurry, dry matter yield par year (5.84 ton DM/ha) was higher than those of fertilizing phosphorus and potassium. The efficiencies of dry matter production with mineral and cattle slurry nitrogen application (kg DM/kg N) were 225 and 15.8~18.7 kg DM/kg N respectively. Especially, these tendencies were higher in diluted application plots than in no-diluted application plots of cattle slurry.

• 한국초지조사료학회지
• /
• 제34권3호
• /
• pp.187-192
• /
• 2014

Alfalfa (Medicago sativa L.) is one of the most important forage legumes in the world. It has been demanded to establish the efficient transformation system in commercial varieties of alfalfa for forage molecular breeding and production of varieties possessing new characteristics. To approach this, genetic transformation techniques have been developed and modified. This work was performed to establish conditions for effective transformation of commercial alfalfa cultivars, Xinjiang Daye, ABT405, Vernal, Wintergreen and Alfagraze. GUS gene was used as a transgene and cotyledon and hypocotyl as a source of explants. Transformation efficiencies differed from 0 to 7.9% among alfalfa cultivars. Highest transformation efficiencies were observed in the cultivar Xinjiang Daye. The integration and expression of the transgenes in the transformed alfalfa plants was confirmed by polymerase chain reaction (PCR) and histochemical GUS assay. These data demonstrate highly efficient Agrobacterium transformation of diverse alfalfa cultivars Xinjiang Daye, which enables routine production of transgenic alfalfa plants.

• 복식문화연구
• /
• 제14권2호
• /
• pp.310-319
• /
• 2006

This study intended to compare and analyze marking efficiencies of tailored jacket based on different cloth and production conditions, 'the width of cloth', 'the number of marking pieces' and 'the direction for marking deployment'. The results were as follows. For the two pieces of markers, the efficiency of the cloth width of 110cm was higher than that of 150cm. As the number of markers increased, the efficiency of cloth width of 150cm was higher than that of 110cm. In the case of one-directional deployment, the results obtained was that the efficiency of two markers was higher than that of three markers, while, in the case of bi-directional deployment, the efficiency of three markers was higher than that of two markers. In the case of one-directional deployment for each size, the marking efficiencies were higher in two markers at the cloth width of 110 cm and higher in three markers at the cloth width of 150 cm. Then, in marking efficiencies according to the direction for marking deployment, bi-direction marker was the most efficient marker, followed by one-direction for each size marker and one-direction marker.

• 한국경제지리학회지
• /
• 제15권4호
• /
• pp.752-765
• /
• 2012

본 연구는 확률변경생산함수를 이용하여 지역노동시장의 인구학적, 산업적, 공간적 특성과 일자리결합 효율성의 관계에 대해 분석하는 것을 목적으로 시도되었다. 주요 결과로는 지역내 50세 이상의 구직자 비율과 공간적 밀도 수준이 높을수록 일자리결합 효율성이 높아지는 것으로 나타났다. 반면 정규직 계약을 제시한 일자리 비중의 증가는 오히려 결합 효율성을 하락시키는 것으로 나타났다. 지역별 결합 효율성의 크기를 비교 분석한 결과 서울의 결합 효율성이 가장 높게 나타났으며 제주가 가장 낮게 나타나, 대체적으로 수도권 지역이 타지역보다 높은 수준의 결합 효율성을 보였다. 마지막으로 결합 효율성은 전산업생산지수와 음(-)의 관계를 보였는데, 이는 불황기에 구직자가 자신의 기대보다 낮은 수준의 일자리를 받아들일 경향이 커지기 때문에 나타난 결과이다.

• 한국경영과학회:학술대회논문집
• /
• 한국경영과학회/대한산업공학회 2003년도 춘계공동학술대회
• /
• pp.683-690
• /
• 2003

This purpose of this research is an attempt to measure and comparatively analyze the efficiencies and RTS(Returns to Scale) using panel data of OECD countries including Korea. In order to achieve this purpose, at first this study used efficient production frontier estimation combined with DEA for obtaining parameter estimates of a efficient production frontier. secondly using estimated results, measured R&D productivity and RTS(Returns to Scale) on all of the OECD countries. thirdly using time-series data related to R&D activity of korea, measured R&D productivity and RTS(Returns to Scale). Finally based on the results of R&D productivity and RTS(Returns to Scale) using efficient production frontier, some policy implications for enhancing the R&D competitiveness and the technological capabilities are discussed.

• 경영과학
• /
• 제16권1호
• /
• pp.173-186
• /
• 1999

Recently many firms are introducing the cellular manufacturing system(CMS) as a means of achieving manufacturing efficiencies. However, most of the research on CMS was mainly for determining the cell formation problems. Since the goal of the CMS is not only a increase production efficiencies, but also to enhance the competitive stength of a firm, it would be reasonable to assume CMS as a business reengineering module rather than an independent technique. The purpose of this study is to align the CMS with reengineering, to present an integrated methodology for constructing the CMS, and to apply the CMS to a firm and verify it. The paper concludes with a brief description of the lessons learend by the CMS project and the limitations of the research are described.

• Asian-Australasian Journal of Animal Sciences
• /
• 제9권5호
• /
• pp.515-517
• /
• 1996

The relative efficiencies of deposition into egg yolk of apo-carotenoic acid ester(APO-E, CAROPHYLL Yellow) and saponified marigold xanthophylls (MX), in the presence of canthaxanthin (CN), were determined using a wheat-based diet. APO-E was deposited with an efficiency of 50 percent and MX with an efficiency between 13 and 20 percent. The dose response relationship for MX was curvilinear with a decreased efficiency at higher concentrations. Canthaxanthin was deposited with and efficiency of 38 percent, irrespective of the source of yellow xanthophylls, up to a dietary concentration of 5.5 mg/kg. At a dietary MX concentration of 8.3 mg/kg the efficiency of deposition of CN declined to 24 percent. The results confirm that the replacement ratio of MX : APO-E is between 3 : 1 and 4 : 1 depending on the dietary inclusion of marigold pigment.

• 한국농공학회지
• /
• 제35권4호
• /
• pp.67-75
• /
• 1993

This study was carried out to investigate the applicability of Solid Contact Process for the improvement of Moving Media Complete Mixing Activated Sludge(MMCMAS) effluents. Laboratory MMCMAS Reactor and MMCMAS/Solid Contact were operated at the hydraulic loading of 122~340 L/m$^2$/d. The conclusions from this study were as follows ; The addition of Solid Contact tank to the MMCMAS reactor has increased the SCOD and SBOD removal efficiencies of 4 to 67% and 2 to 41%, respectively. In addition, the increments of nitrification rates were about 13 to 46%. It was also observed that the addition of Solid Contact tank has greatly increased the organic removal efficiencies at the higher hydraulic loading rates and also decrement of sludge production rates was 0.1 gVSS/gBODrem. It was therefore concluded that the addition of Solid Contact tank could have polished the effluent of MMCMAS at the higher hydraulic loading rates.

• Membrane and Water Treatment
• /
• 제10권3호
• /
• pp.191-199
• /
• 2019

In this study, we investigated the cultivation possibility using Hydrodictyon reticulatum in a continuous raceway pond as a tertiary sewage treatment plant. The cultivation possibility was evaluated by varying the light quantity, wavelength, and hydraulic retention time (HRT). Experimental results showed that the growth rates of algae and the removal efficiencies of nutrients increased as the light quantity increased, and the maximum photosynthetic rate was maintained at $100{\mu}mol/m^2{\cdot}s$ or higher. When wavelength was varied, nutrient removal efficiency and growth rate increased in the following order: green light, red light, white light, and blue light. The nutrient removal efficiencies and algae productivity in HRT 4 d were better than in HRT 8 d. We conclude that if Hydrodictyon reticulatum is cultivated in a raceway pond and used as a tertiary treatment facility in a sewage treatment plant, nutrients can be effectively removed, and production costs can be reduced.