• 한국유체기계학회 논문집
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• 제17권2호
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• pp.24-29
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• 2014

In general, a large-capacity axial flow fan is used for industrial processes or ventilation in a social overhead capital infrastructure. The main characteristics of the large axial-flow fan need a lot of electrical power consumption and operate 24 hours a day, 365 days a year. Since the large axial flow fan consumes several hundreds to thousands kW per hour, both manufacturer and consumer are struggling to select high efficiency products for saving energy and reducing operation cost. Therefore, the performance testing should be accurately conducted in experimental equipments. The performance estimation and uncertainty of measurement of the axial-flow fan gathered from the result from nozzle shaped testing equipments certified with ANSI/AMCA standard and duct shaped testing equipment under the same experimental condition. The experimental results from both facilities have maximum 17% differences in performance evaluation and uncertainty of measurement. As considering that the differences, it is doubt about the reliability of testing result. The test was repeated with the specific term during 12 months because it is important to fully reflect the real conditions and to decide the repeatability of data. The evaluation of duct type testing facilities was failed to get an uncertainty measure. Testing results were previously published. As a series of previous paper, axial fan (∅1690 mm) and duct type testing facilities were fabricated. The purpose of fabricating testing equipment was testing an uncertainty measurement under the controlled environments.

• 펄프종이기술
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• 제47권5호
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• pp.74-79
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• 2015

Wood powder is widely used in paperboard mills to increase bulk and reduce drying-energy consumption, but this material also deteriorates paper strength because it interferes with the bonds between fibers. Although there have been many studies done to improve the strength of paperboard containing wood powder, specific applications have not recently been observed in paperboard mills. In this study, we carried out a new approach for improving paperboard strength by developing a new organic filler with the ability to increase the bonds between fibers. The residue of tapioca starch was used as raw material to manufacture an organic filler. The functionalities, including bulk and strength, were evaluated by making handsheets containing either wood powder or tapioca organic filler, or a mixture of the two, and measuring their physical properties. The organic filler showed lower bulk improvement and higher paperboard strength than the wood powder. The mixture of tapioca organic filler and wood powder showed improved paperboard strength compared to wood powder alone. Therefore, tapioca residue can be used as a raw material to manufacture an organic filler for paperboard mills.

• 한국물환경학회지
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• 제33권3호
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• pp.334-340
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• 2017

A pilot-scale electrodialysis system was designed and constructed to treat groundwater polluted with arsenic and manganese. Synthetic groundwater, in which some amount of arsenic and manganese was added to make 500 mg/L of Mn and $50{\mu}g/L$ of As, was used as a feed for the ED system. The limiting current density, linear water velocity, applied voltage, and membrane surface area were investigated to obtain efficient and economic operation of the ED system. The linear water velocity was increased 0.74 cm/s to 11 cm/s based on evaluation of limiting current density. The water quality of diluate for 85 minutes of operation was satisfied with water quality criteria for drinking water using the ED system with 14 pairs of ion exchange membranes. The increased membrane pairs to 21 and 42 pairs were very effective to reduce conductivities of the diluate. The operation cost of the ED system was assessed using specific energy consumption, which was $1.065{\sim}1.2kWh/m^3$. Considering low salt concentrations of the groundwater, improvement of the ED system are required to increase current utilization and to apply low voltage while the ED system was applicable to produce drinking water.

• 상하수도학회지
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• 제29권1호
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• pp.89-96
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• 2015

Smart water grid is a water network with communication to save water and energy using various water resources. In smart water grid, water product from the various sources can be blended to be supplied to end-users. The product water blending was reported by literatures while feed water blending has been rarely reported so far. In this work, a commercial reverse osmosis (RO) system design software provided by a membrane manufacturer was used to elucidate the effect of feed water blending on the performance of seawater reverse osmosis (SWRO) plant. Fresh water from exisiting water resource was assumed to be blended to seawater to decrease salt concentration of the RO feed water. The feed water blending can simplify the RO system from double to single pass and decrease seawater intake amount, the unit prices of the RO system components including high pressure pump, and operation risk. Due to the increase in RO plant capacity with the feed water blending, however, the RO membrane area and total power consumption increase at higher water blending rates. Therefore, a specific benefit-cost analysis should be carried out to apply the feed water blending to SWRO plants.

• 한국식품영양학회지
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• 제26권3호
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• pp.329-338
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• 2013

This study is conducted to compare the problems affecting dietary habits and health status between a long-term exercise group and non-exercise group of males older than 50 years. Most subjects of the two groups consider regular exercise to be the most important factor for maintaining health, and recognize hypertension as the number one concern. The most common nutritional supplement among subjects is multiple vitamins, and sleeping time range from 6~8 hours. Breakfast fasting rate was 15.9% among non-exercise group (NEG), where overeating and eating out rates were higher among exercise group (EG) when comparing to NEG. Fasting rates of breakfast, and consumption rates of milk and dairy products, vegetables such as kimchi, and fruits and fruit juices are higher among the EG. Overeating and eating out rates are lower among NEG, whereas eating rates of proteins like meat, fish, eggs, beans, fried foods, high-fat meats carbonated drinks, ice cream, and salt intakes are higher. Rates of health, dietary habits, and nutrient intakes are higher among EG. Energy intakes among the two groups were below the standard level, Vitamin $B_2$ intake is low in EG, and folic acid and calcium intakes were higher in NEG. The exercising group care more about health, eating habits and nutrient intakes, and low smoking rates are being observed. Thus, specific dietary improvement programs for adult men, are required, and it is necessary to consider the practice of nutrition education.

• Journal of Plant Biotechnology
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• 제30권4호
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• pp.387-397
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• 2003

During the first half of twentieth century, even though the importance of non-calorie essential micronutrients of 13 vitamins and 17 minerals has been known to alleviate nutritional disorder; the primary objective of agriculture and plant breeding programs has been to increase the productivity and seed yields, and macronutrients of proteins, fats, and carbohydrates made up the bulk of foodstuff which were used primarily as an energy source. In the last decade it has been found that non-essential micronutrients encompass a vast group of phytochemicals including antioxidants that are not strictly required in the diet but when present at sufficient levels work as health-promoting chemicals. Nowadays agricultural crops are grown for health rather than for food or fiber, and modifying the nutritional compositions of plant foods has become an urgent health issue. To ensure an adequate intake of essential vitamins and minerals, and to increase the consumption of health-promoting phytochemicals, the researches on plant secondary metabolism have been made. The attempt to improve nutritional quality of crops has been blocked by a lack of basic knowledge of plant metabolism. The advent of genomics era enabled new approaches to make crossing regardless of species, family, or phylum barriers, and the accumulation in our basic knowledge on plant secondary metabolism during the coming decade would be tremendous. As the major staple crops contain insufficient amount of many micronutrients, fortification strategy will be a necessary practice. Elevated intake of specific vitamins, C, E, and $\beta$-carotene, mineral selenium, antioxidants, and phytochemicals significantly reduces the risk of chronic disease such as cancer, cardiovascular disorder, diabetis, and other degenerative disease associated with aging. As the attempt to improve the nutritional quality of crops requires the basic knowledges on plant metabolism, plant biochemistry, human physiology, and food chemistry, strong interdisplinary collaboration among plant biotechnologists, human nutritionists, and food scientists will be needed. Inhibition of cancer, cardiovascular disease, and other degenerative disorder may be the biggest goal facing nutritional plant breeders. But the assumption that simply increasing dietary level of any compound will necessarily improve human health is a dangerous idea because many plant secondary products and dietary contaminants have paradoxical (hermetic) effects. Before biotechnical manipulation is undertaken to elevate or reduce any individual constituent of crops, the contribution of the micronutrient to human health must first be investigated.

• 센서학회지
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• 제8권4호
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• pp.327-332
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• 1999

비표면적이 약 $200\;m^2/g$인 ${\gamma}-Al_2O_3$를 합성하여 얻은 ${\gamma}-Al_2O_3$ 담체에 Pd, Pt와 같은 귀금속 촉매를 첨가하여 접촉연소식 가스감지소자를 제작하였다. 제작된 센서는 최적동작을 위한 인가전압 1.75 V에서 소모전력은 약 500 mV였고, 부탄, 메탄 및 프로판 각각 100 %LEL에 대해서 약 120 mV의 높은 감도 특성을 보였다. 제작된 센서는 탄화수소 가스 농도에 대한 선형성, 재현성, 그리고 상대 습도변화에 대해서 안정된 감도 특성을 보여 주었다. 그리고 약 100일 동안 부탄 가스에 대해서 안정된 센서 감도 특성을 보여 주었다.

• 공업화학
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• 제25권4호
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• pp.346-351
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• 2014

인구증가와 산업화로 인한 물의 수요 급증에 따른 제3세대 수처리 기술로써 정전기적 흡 탈착 공정에 대한 연구가 진행되고 있다. 정전기적 흡 탈착 기술의 경우, 기존에 사용되는 수처리 방법들에 비해 에너지 소비량이 적으며, 재생시에 2차 오염이 발생하지 않아 차세대 수처리 기술로 주목 받고 있다. 정전기적 흡 탈착 기술에서 이온 제거를 위한 전극 물질로는 넓은 비표면적과 높은 전도도를 갖는 탄소 전극이 주로 사용된다. 현재 다양한 탄소 물질로 이루어진 전극에 대한 연구가 수행되고 있으며, 특히 비표면적, 기공 분포에 따른 흡 탈착 연구가 활발히 진행되고 있다. 본 총설에서는 다양한 탄소 물질 및 기공 분포에 따른 영향을 분석하고, 메조기공과 마이크로기공이 조화를 이루는 최적의 조건을 제시하고자 한다.

• 한국식품과학회지
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• 제16권1호
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• pp.37-40
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• 1984

국내도정공장에 간단히 부착운용할 수있는 미강안정화 처리용 저렴 Extruder (K-E3030 - 100. 처리능력 시간당 400kg)를 개발하였다. 부산된 미강을 그대로 안정화기로 처리하면 pellet형으로 성형된 안정화 미강을 얻을 수 있다. 안정화 처리온도는 원료투입속도를 조절함으로서 $95-150^{\circ}C$ 범위에서 조절이 가능하며, 이때 전력 소모량은 원료미강kg 당 0.060-0.070KWH이었다. 안정화 처리미강은 처리온도에 따라 용적밀도가 원료미강의 0.313g/cc에서 0.526-0.601g/cc로 증가하였고, 수분함량은 13.08%에서 10.41-6.03%로 감소하였다. 그리고, 처리온도가 $120^{\circ}C$이상인 경우에는 학절기의 기후 조건하에서 9 주간 저장하여도 유리 지방산의 함량이 15%를 넘지 못하였다.

• 한국가스학회지
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• 제12권3호
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• pp.7-12
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• 2008

본 연구에서는 DME가 함유된 LPG 연료를 불꽃 점화 기관에서 적용 가능 여부를 실험적으로 살펴보고 있다. LPG와 DME가 함유된 혼합연료로 엔진 구동시 엔진출력, 배출가스 특성, 연소안정성 등의 항목에 대한 실험을 $1200{\sim}5200\;rpm$에서 수행하였다. 결과를 살펴보면 20% 내외의 범위에서 DME를 혼합하는 경우 안정된 연소성능을 얻을 수 있었으며 10%까지는 엔진 출력 저하가 거의 없다. 하지만 혼합율이 증가할수록 DME 연료는 LPG보다 에너지 밀도가 낮으므로 출력이 감소하고 제동연료소비율은 증가하는 현상을 보인다. LPG/DME 혼합연료는 향후 DME 시장을 넓혀 나가는 최선의 방법이 될 것이다.