• 한국환경보건학회지
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• 제24권1호
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• pp.112-119
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• 1998

The objective of this study was to investigate the effect of bulking agents including cow manure, saw dust and rice straw in the ripening of leather sludge for vermistabilization. The changes of the waste properties for ripening time for 50 days were observed according to the various mixture ratios of leather sludge and bulking agents. The pH values of the mixture wastes were decreased from 7.5-8.0 to 6.4-7.3 with the ripening time for 50 days, and it was indifferent of the mixture ratio and type of the bulking agent. The initial value of oxidation-reduction potential(Eh) of the mixture waste was a negative(-)value indicating an unfavorable condition for earthworm life, but the values of Eh were increased with the ripening time. The increase rate of Eh value was proportional to the mixture ratio of bulking agents, but the increase rate for saw dust was higher than that of the cow manure and the rice straw. The value of alkalinity was also changed into the favorable range for earthworm after 50 days except for 10% of the mixture ratio of the bulking agents. When the mixture ratios of the bulking agents were increased from 10% to 40%, the growth characteristics of earthworms were increased from 31.7% to 95% for the survival rate, 103% to 225% for the liveweight increase rate and 32% to 91% for hatching rate of the cocoons. It can be concluded that the proper content of the bulking agents in the leather sludge to ensure effective vermistabilization was over 30%, when the mixture was ripened during 50 days. The contents of heavy metals in the ripened sludge were lower than the other regulatory standards for compost.

• 한국수소및신에너지학회논문집
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• 제23권5호
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• pp.493-502
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• 2012

Syngas laminar burning velocity measurements were carried out at atmospheric pressure and ambient temperature using the Bunsen flame configuration with nozzle burner as a fundamental study on flame stability of syngas fuel. Representative syngas mixture compositions ($H_2$:CO) such as 25:75%, 50:50% and 75:25% and equivalence ratios from 0.5 to 1.4 have been conducted. Average laminar burning velocities have been determined by the stabilized nozzle burner flames using the angle method, radical surface area method and compared with the data obtained from the other literatures. And the results of each experimental methodologies in the various composition ratios and equivalence ratios were coincided with the result of numerical simulation. Especially, it was confirmed that there was necessary to choice a more accurate measurement methodology even the same static flame method for the various composition ratios of syngas fuel including hydrogen. Also, it was reconfirmed that the laminar burning velocities gradually increased with the increasing of hydrogen content in a fuel mixture.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2105-2119
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• 2015

This paper reported the experimental result of dielectric properties of Refined, Bleached and Deodorized Palm Oil (RBDPO) combined with 0-50% of Refined, Bleached and Deodorized Soybean Oil (RBDSO). The dielectric strength and relative permittivity of RBDPO/RBDSO was higher compared to mineral oil at all ranges of ratios and temperatures which indicated a positive sign for its possible use as insulating liquid in a transformer. All ratios of the RBDPO/RBDSO mixture also demonstrated lower dissipation factor compared to mineral oil at 40℃, 70℃ and 90℃. Apart from that, the kinematic viscosity for the oil mixtures shown exceeded the IEC 60296 as well as the mineral oil results. 70%RBDPO/30%RBDSO mixture ratio was chosen as the best mixing percentage after comparison was made with the mineral oil and IEC 60296 standard where the mixture accumulated the most satisfactory of dielectric properties hence making it as the potential candidate for palm and soybean-based transformer oil.

• 한국정밀공학회지
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• 제16권8호
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• pp.149-154
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• 1999

FRMLs(Fiber Reinforced Metal Laminates) is a new type of hybrid materials. FRMLs consists of high strength metal and fiber which are laminated using a structural adhesive bond(epoxy resin). The effect of resin mixture ratios on the fatigue crack propagation behavior and mechanical property of Aramid fiber reinforced aluminum composites was investigated. The epoxy, diglycidylether of bisphenol A(DGEBA) was cured with methylene dianiline(MDA) with or without accelerator(K-54). Eight kinds of resin mixture ratio were tested for the experiment ; five kinds of FRMLs(1))epoxy & curing agent) and three kinds of FRMLs(2)(epoxy & curing agent & accelerator). FRMLs(2) have a more effective characteristics on the fatigue crack propagation behavior and mechanical property than FRMLs(1)

• 분석과학
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• 제20권6호
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• pp.502-507
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• 2007

X 선 회절법은 물질 내부에 원자의 배열 상태를 연구하는데 널리 사용되는 실험 방법으로써 넓은 응용 범위를 가지고 있다. 특히 분말 X 선 회절법은 비파괴적으로 다양한 형태의 시료에 대한 측정이 가능하기 때문에 결정의 배향성, 결정의 크기, 결정 내부의 응력 측정 등에 널리 이용되고 있다. 분말 X 선 회절 방법을 이용하여 혼합물의 성분을 정량적으로 측정하기 위해서는 시료를 구성하고 있는 source 스펙트럼을 도출하고 혼합된 시료의 XRD 스펙트럼에 회귀식을 적합시켜 혼합물 구성비를 얻는 방법이 제안된 바 있다. 그러나 구성성분의 특성상 스펙트럼의 피이크가 폭이 좁고 민감한 경우에는 노이즈의 영향을 받아 도출된 source 스펙트럼이 원래의 순수성분의 형태와 달리 나타날 수 있다. 특히 순수성분 시료를 구할 수 없거나 측정이 불가능한 경우 혼합물 구성비 측정에 어려움이 있다. 본 연구에서는 노이즈 간섭에 의한 source 스펙트럼 도출의 문제를 해결하는 방안으로 비음독립성분분석을 이용하여 혼합된 미지시료로부터 순수한 성분에 해당하는 스펙트럼을 분리해내는 방법을 제안하고자 한다.

• Asian-Australasian Journal of Animal Sciences
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• 제14권7호
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• pp.960-965
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• 2001

The effects of different feeding ratios of concentrate (C) and roughage (R) on balance of long chain fatty acids and microbial fatty acids in the rumen of sheep were investigated. The diets were divided into 8:2 (concentrate feeding), 4:6 (middle mixture) and 0:10 (roughage feeding) ratios (C:R). Duodenal digesta was collected through 24 hours after feeding. Biohydrogenation rate, total duodenal flow of fatty acids and microbial fatty acids were measured. Total duodenal flow of fatty acids was significantly (p<0.05) increased with increasing concentrate. Total duodenal flow of fatty acid was greater than intake of fatty acid in all diets. In comparison with intake of each fatty acid, duodenal flow of stearic acid ($C_{18:0}$) remarkably increased in all diets. Biohydrogenation rate for total C18 unsaturated fatty acids in the rumen tended to increase (p<0.10) when sheep were fed the middle mixture. In particular, biohydrogenation rate of linoleic acid ($C_{18:2}$) and linolenic acid ($C_{18:3}$) with the middle mixture were highest (p<0.05) compared with other diets. Duodenal flow of protozoal fatty acids was significantly (p<0.05) increased with the increased supply of concentrate. That of bacterial fatty acids was significantly (p<0.05) increased with both concentrate diets compared with the roughage feeding diet. $C_{18:0}$ occupied the greater part of both protozoal and bacterial fatty acids in all treatments. Results indicated that biohydrogenation of free unsaturated fatty acids was actively carried out when the middle mixture diet was supplied, and that microbial uptake and synthesis of fatty acids were accelerated by adding the supply of concentrate.

• International Journal of Automotive Technology
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• 제2권3호
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• pp.93-101
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• 2001

Distribution of fuel-air mixture has a strong influence on performance and emissions of a compressed natural gas (CNG) engine. In this paper, parametric study is performed by KIVA-3V to investigate fuel-air mixture with respect to injection timing, cycle equivalence ratio and engine speed. With open-valve injection intensive mixing during intake and compression stroke results in relatively homogeneous mixture in the cylinder. Sequential induction of fuel-air mixture and fresh air results in stratification in the cylinder among the test cases at closed-valve injection. There is close similarity in the calculated distributions of the mixture in the cylinder with different cycle equivalence ratios and engine speeds. The results are compared against pressure traces and flame images obtained in a single cylinder engine converted from a 11L six-cylinder heavy duty diesel engine.

• International Journal of Precision Engineering and Manufacturing
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• 제1권1호
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• pp.33-41
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• 2000

Fiber reinforced metal laminates(FRMLs) were new type of hybrid materials. FRMLs consist of high strength metals(Al 5052-H34) and laminated fiber with structural adhesive bond. The effect of resin mixture ratios on the fatigue crack propagation behavior and mechanical properties of aramid fiber reinforced aluminum composites was investigated. The epoxy, diglycidylether of bisphenol A(DGEBA), was cured with methylene dianiline(MDA) with or without an accelerator(K-54). Eight kinds of resin mixture ratio were used for the experiment ; five kinds of FRMLs(1)(mixture of epoxy and curing agent) and three kinds of FRMLs(2)mixture of epoxy, curing agent and accelerator). The characteristic of fatigue crack propagation behavior and mechanical properties FRMLs(2) shows more effecting than that of FRMLs(1).

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.231-234
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• 2004

The experiments on some organic materials used in SAPS are carried out for the better sulfate reduction efficiency and the longer lifetime. Organic materials include spent mushroom compost, sewage sludge, oak chip compost and the combination of there. Reactors with mushroom compost, sewage sludge, the mixture of mushroom compost and sewage sludge, and the mixture of mushroom compost and oak chip compost maintained pH higher than 6.0. Reactors with mushroom compost, the mixture of mushroom compost and sewage sludge, and the mixture of mushroom compost and oak chip compost maintained reduction condition. Reactors with sewage sludge, oak chip compost and the mixture of sewage and oak chip compost produced COD less than 2,000ppm. Reactors with sewage and the mixture of mushroom compost, sewage sludge, oak chip compost showed about 60% of sulfate removal ratios.

• 아시안잔디학회지
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• 제23권2호
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• pp.271-278
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• 2009

본 연구는 골프장의 상토조성 시 사용되는 토양개량제의 적절한 활용과 이해를 위해 입경과 화학적 특성이 비슷한 무기성 토양개량제의 3종의 혼합비율에 따른 모래상토의 물리 화학적 특성변화를 조사하였다. 토양개량제의 혼합비율에 따라 상토의 물리 화학성을 조사한 결과는 다음과 같다. A와 C가 pH가 95% 수준에서 상관성을 나타내었고, C의 양이온치환용량이 95% 수준에서 상관성을 보여 토양개량제의 특성에 따라 상토의 토양화학성에 영향을 주었다. 상토의 토양물리성 결과를 통해 USGA 기준으로 평가할 때, 최적의 혼합비율은 토양개량제 A와 B에서는 3%였고, C는 7~10% 였다. 각 토양개량제들의 혼합에 따른 토양물리성변화에 가장 큰 영향을 미치는 물리적 요인은 총공극량이었다. 토양개량제의 혼합비율에 따른 토양개선효과 를 비교할 때, B는 모세관공극과 비모세관공극에서, C는 모세관공극, 총공극 및 수리전도 도에서 고도의 상관성을 나타내었다(P<0.05). 이들 결과를 통해 골프코스의 상토조성에 사용되는 무기성 토양개량제는 그 종류와 혼합비율이 USGA 상토의 뿌리층 개량의 토양 이화학성에 영향을 미치고 있음을 알 수 있었다.