• Title/Summary/Keyword: water-energy

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Position-Dependent Cathode Degradation of Large Scale Membrane Electrode Assembly for Direct Methanol Fuel Cell (직접 메탄올 연료전지용 대면적 막-전극 접합체 공기극의 위치별 열화 현상)

  • Kim, Soo-Kil;Lee, Eun-Sook;Kim, Yi-Young;Kim, Jang-Mi;Joh, Han-Ik;Ha, Heung-Yong
    • Journal of the Korean Electrochemical Society
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    • v.12 no.2
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    • pp.148-154
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    • 2009
  • With respect to the durability of large scale ($150cm^2$) membrane electrode assembly (MEA) of direct methanol fuel cell (DMFC), degradation phenomena at cathode is monitored and analyzed according to the position on the cathode surface. After constant current mode operation of large scale MEA for 500 hr, the MEA is divided into three parts along the cathode channel; (close to) inlet, middle, and (close to) outlet. The performance of each MEA is tested and it is revealed that the MEA from the cathode outlet of large MEA shows the worst performance. This is due to the catalyst degradation and GDL delamination caused by flooding at cathode outlet of large MEA during the 500 hr operation. Particularly on the catalyst degradation, the loss of electrochemically active surface area (ECSA) of catalyst gets worse along the cathode channel from inlet to outlet, of which the reason is believed to be loss of catalysts by dissolution and migration rather than their agglomeration. The extent of loss in the performance and catalyst degradation has strong relation to the cathode flooding and it is required to develop proper water management techniques and separator channel design to control the flooding.

Effect of Sodium Hydroxide plus Hydrogen Peroxide Treated Mustard (Brassica campestris) Straw Based Diets on Rumen Degradation Kinetics (In sacco), Fermentation Pattern and Nutrient Utilization in Sheep

  • Mishra, A.S.;Misra, A.K.;Tripathi, M.K.;Santra, A.;Prasad, R.;Jakhmola, R.C.
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.3
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    • pp.355-365
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    • 2004
  • Two experiments were conducted to determine the effect of alkaline hydrogen peroxide (AHP) treatment (1% NaOH+1.5% $H_2O_2$; 1 AHPMS, 2% NaOH+1.5% $H_2O_2$; 2AHPMS) on rate and extent of degradation of mustard straw (MS) in sacco in sheep, and its in vivo digestion and ruminal fermentation characteristics when fed to sheep with concentrate (200 g per sheep daily). The treatment of straw with 1 and 2% AHP increased its sodium content by 148 and 296% to that of untreated straw (UMS). There was significant decrease in NDF and hemicellulose contents of AHP treated straw and increase in cellulose and lignin contents. Phenolic acids like ferrulic, $\rho$-coumaric and o-coumaric significantly (p<0.001) reduced by AHP treatment of mustard straw. In first experiment the in sacco degradation of DM, OM and NDF was significantly (p<0.01) greater for 2 AHPMS than for UMS at all incubation periods. The disappearance of nutrient from 1 AHPMS and 2 AHPMS treated straws continue to increase up to 96 h whereas in UMS the peak disappearance was found at 48 h. By using the equation {(y=a+b) ($1-e^{-ct}$)} the degradation rates (c) for DM, OM, and NDF were significantly higher for UMS than AHP treated straws. Level of alkali (1 and 2%) had significant effect on degradation characteristics (a, b, c and $P_{0.05}$) of DM and NDF fraction of MS. However, the effect was not pronounced on OM fraction of MS. In feeding experiment, the intake of nutrients for DM, OM, cell wall constituents and energy was higher on 2 AHPMS, whereas no effect on the digestibility of these nutrients was observed. The apparent nitrogen retention was higher (p<0.05) both in 1 and 2 AHPMS groups. Water intake by animals was significantly increased due to AHP treated mustard straw feeding. Rumen liquor pH was higher in 2 AHPMS fed animals. The $NH_3-N$ of rumen liquor was not affected by feeding of AHP treated MS based diets. Total VFA concentration was significantly (p<0.01) higher in UMS fed group. The fractional out flow rate of DM was higher (p<0.05) in animals fed on 2 AHPMS diets compared to UMS and lAHPMS fed groups. The population of large holotrichs was higher (p<0.05) on AHP treated MS fed diets compared to UMS. The study indicated that treatment of mustard straw with AHP changed its chemical composition towards a better feed. The nutritive value of 2% AHP treated mustard straw was better in terms of dry matter intake and apparent nitrogen retention. The higher in sacco DM, OM and NDF disappearance however, was not confirmed by in vivo data in this study.

Environmental and Genetic Aspects of Obesity in Broilers (육계의 비만현상에 관한 고찰)

  • 김재홍
    • Korean Journal of Poultry Science
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    • v.9 no.1
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    • pp.1-16
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    • 1982
  • Excessive fat deposition, particularly in the abdominal region, has become a problem in broiler production. When the caloric intake exceeds the body demands for energy, excess food is stored as fat in broilers. Researchers have shown that fat deposition varies with breed, strain, sex age, nutrition, exercise, ambient temperature and rearing systems. These factors affect fat deposition through their effects on the size or the number of adipose cells or a combination of both. In some measurements on live birds to predict body fat, the wet weight and percentage fat of skin in pectoral feather tract are significantly correlated with percentage abdominal fat. But these correlation coefficients are not so high. Therefore, correlation coefficients indicate that these measurements on live birds ate not useful for estimating body fat weight and percentage. Most reports show that an increase in the proportion of carcass fat, when measured at a given age, is correlated with selection for increased body weight. On the other hand some research results show that selection for body$.$weight gain dose not lead to an alteration in the proportion carcass fat when measured at a given body weight. Besides, selection for improved food conversion efficiency alone resulted in a decrease in carcass fat and an increase in protein and water when measured at either a given age or body weight, Thus eventhough it is uncertain whether carcass fat is increasing as a result of body-weight selection in broilers: however it is clear that selection for improved food conversion efficiency, either alone or in combination with growth rate, should result in leaner carcasses than selection for growth rate alone.

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Remediation of the Diesel Contaminated Soils Using Thermally Enhanced Soil Vapor Extraction Process with Microwave Heating (마이크로웨이브 가열 토양증기추출 공정에 의한 경유 오염 토양처리)

  • 김종운;박갑성
    • Journal of Soil and Groundwater Environment
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    • v.9 no.1
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    • pp.39-46
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    • 2004
  • Removal efficiencies for diesel fuel and diesel hydrocarbons ($C_10$$C_22$) using microwave-enhanced SVE process were evaluated with dry and moist soil, respectively. Diesel removal rates of microwave-enhanced SVE process were 7 times for dry soil and 1580 times for moist soil as great as those of the SVE process without microwave heating. High dielectric property of water contents may accelerate the absorption of microwave energy into soil and thus vaporized the diesel fuel components drastically. The diesel removals were 67.7∼78.4% for $C_10$ and $C_12$, and 0∼18.5% for $C_14$$C_22$ for dry and moist soil with SVE process only. On the other hand, dry soil with microwave-enhanced SVE process showed 89.3∼99.4% removal for $C_10$ to and $C_12$ and 35.6∼67.0% for hydrocarbons over $C_14$. All hydrocarbons ($C_10$$C_22$) studied were significantly removed (93.6∼99.8%) for moist soil with microwave-enhanced SVE process.

Preparation Condition and Product Quality of Precooked Redbean Porridge (즉석팥죽 제조를 위한 가공조건 및 제품의 품질)

  • Kim, Chong-Tai;Kim, Bok-Nam
    • Korean Journal of Food Science and Technology
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    • v.26 no.3
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    • pp.305-309
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    • 1994
  • Precooked powder of redbean porridge (RP) was prepared by the series of process extrusion, drying, milling and blending with a mixture of whole redbean flour and corn starch and others. The optimum process and quality of products for RP were investigated. After extrusion under the moisture content 24 to 26%, twin screw speed 350 rpm, extrusion temperature 150 to $155^{\circ}C$ and feed rate 60 kg/hr, the product had a higher quality with its natural redbean flavor/color. During the extrusion process, extrusion temperature and specific mechanical energy increased from 150 to $198^{\circ}C$ and from 134 to 144 kwh/ton respectively, as the amount of addition water decreased from 6 to 2 kg/hr. By the hot air drying of redbean extrudate (RE). it could be dried below to 4% moisture content, of which level considered as an optimal moisture content for anti-caking of the powdered product, at $80^{\circ}C$ for 4hrs and at $100^{\circ}C$ for 1.5 hrs respectively. In the sieve analysis of extrudate powder, when the product milled through a mesh size of 0.5 mm or 1.0 mm, about 80% or 65% of the feed was passed a 65 mesh screen respectively. Moisture absorption of final blended products was formed a cake under 100% of relative humidity after 13 hrs of storage. As the amount of RE powder reduced, the flavor score of products decreased by sensory evaluation of products prepared by the different ratio of RE powder, corn starch and sugar.

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Product Characteristics as Factors of Process Parameters in Starch Phosphates Preparation by Twin-screw Extruder (이축압출성형기로 인산전분 제조시 Process Parameters에 따른 제품의 특성)

  • Kim, Chong-Tai;Kim, Dong-Chul;Kim, Chul-Jin;Kim, Hae-Sung
    • Korean Journal of Food Science and Technology
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    • v.23 no.2
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    • pp.235-240
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    • 1991
  • Starch phosphates were prepared from the corn starch mixed with 2% sodium tripolyphosphate by twin-screw extruder with a feed rate of 20 kg/hr and an extrusion temperature of $130^{\circ}C$, and the effects of extrusion variables on the physicochemical properties (target parameters) of starch phosphates were investigated. Interrelations of system parameters (specific mechanical energy and extrudate moisture) and rheological properities of starch was analyzed by using the response surface analysis. Degree of substitution (DS) was increased with increasing the feed moisture, and showed the maximum value at the screw of near 250 rpm, Degree of gelatinization was proportionally increased with increasing the screw speed and decreasing the feed moisture. Apparent viscosity of the paste was increased with increasing the feed moisture, but it was not significantly affected by the screw speed. It was found by scanning electron microscopy that the starch microgranules were much more degradaded, and as consequent result, the intrinsic viscosity was decreased, whereas, water solubility index was increased. The rate of retrogradation of the gels was retarded with increasing DS and decreasing viscosity.

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Study on the Shapes of Jung-kwa, Gi-kwa, Sin-kwa, Hyul-kwa (정기신혈과(精氣神血科)의 형상(形象)에 대한 연구)

  • Choi Byung-Tae;Choi Yung-Hyun;Baek Geun-Gi;Lee Yong-Tae
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.19 no.5
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    • pp.1181-1190
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    • 2005
  • After study about the shapes of Jung, Gi, Sin, Hyul-kwa advocated by Master Jisan, the conclusions are drawn as follows. It pursues the rules of universe being changed from formless to concrete objects that the Body Essence, Vital energy, Mentality, and Blood are materialized to Jung, GE, Sin, Hyul-kwa. It can be drawn an inference from the next three theories that Jisan considered Jung, Gi, Sin, Hyul-kwa as round, square, reverse triangle, and triangle or oval shape. First, it was taken to following the shapes of viscera. Namely Jung-kwa was taken as Kidney, Gi-kwa as Lung, Sin-kwa as Heart, Hyul-kwa as Liver. Second, it was adopted from five kinds of constitutions according to the five elements in [Yeongchu Yin and Yang twenty five shapes] that is Jung-kwa is purchased with Water-earth phases, Gi-kwa with metal phase Sin-kwa with fire phase, Hyul-kwa with Wood phase, Third, it is taken in order to eliminate contradictions. Hyul-kwa disliking to move is assumed to round shape to easily move. Gi-kwa tending to disperse is chosen to square in order to be unmoved. Sin-kwa declining to stagnate of seven emotions is pursued to reverse triangle to compose oneself. Hyul-kwa inclining to gather is preferred to acreage phase to harmonize ascending tendency. Among shapes which Jisan was divided Hado, Nakseo, Bokhee pal kwoe, Moonwang pal kwoe, Jung-kwa as round is Hado, Gi-kwa as square is Nakseo, Sin-kwa as reverse triangle is Bokhee pal kwoe order shape, Hyul-kwa as acreage phase or oval shape is accord with Moonwang pal kwoe order shape. The reason being classified into Jung, GE, Sin, Hyul-kwa from the shapes of the face is that the face is the place to reflect the whole conditions of the body connected with all of the viscera and meridian system such as semen of plants. Above contents are drawn an inference from the transcription of Jisan's lectures and his writings. And it is considered that insufficient parts of the Jisan's theory must be demonstrated continuously.

Lake's Function on Control of Refractory Dissolved Organic Matter caused by Upstream Rivers to Andong Lake and JinYang Lake (안동호와 진양호의 상류하천발생 난분해성유기물질 제어에 대한 호소의 기능)

  • Choi, Byoung-Woo;Kang, Mee-A;Sohn, Ho-Yong
    • Journal of Wetlands Research
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    • v.13 no.2
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    • pp.343-353
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    • 2011
  • Variations of load in both DOM and RDOM of inflowing rivers to lakes were in the range of 5.01-7.29(${\times}10^2$ kg/day) for AD lake and 1.23-3.75(${\times}10^3$ kg/day) for JY lake during the research period excluding the period directly affected by the strong rainy season and the monsoon and typhoon season. We observed a good relationship($R^2$ > 0.8) between SS load and DOM load (including RDOM) in both inflowing rivers to JY lake. Therefore, it was determined that SS would be an alternative parameter with a rapid and energy-efficient method for the analysis of both DOC and RDOC, which require the analytical equipment and a long time period. Both AD lake and JY lake may act as a DOM(including RDOM) source through primary production in the fall season. Because AD lake and JY lake may not act as a DOM buffer zone, both lakes couldn't control the DOM and RDOM in spring before the rainy season. Therefore to improve water quality in downstream rivers is needed to remove pollutants such as DOM and RDOM before inflowing to these lakes in upstream rivers, or to have the unique landscape of wetlands as a buffer zone.

The Economic Impact of Contaminated and Noxious Sites : A Meta Analysis (오염-유해시설의 경제적 영향 : 메타분석)

  • Won, Doo Hwan
    • Environmental and Resource Economics Review
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    • v.17 no.1
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    • pp.165-196
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    • 2008
  • This paper reports a quantitative meta analysis of the economic impacts of localized noxious and contaminated sites. Using either hedonic property value or stated preference methods, economists have studied the effects of contamination or noxious activities, or the benefits realized from their elimination, on real estate prices at more than 40 sites. In support of wise public and private investments in environmental quality, most of these studies aim to inform decision makers about the benefits of remediation and cleanup. Their results vary considerably, but there has been no previous systematic effort to analyze the differences and identify shared insights. This study uses established methods of meta analysis to identify points of agreement and differences in this body of literature. The studies are characterized by the type of site, modeling approach, geographic extent of impacts, data features, and other key factors that underlie their value estimates. The impact estimates are normalized as proportional effects on property values. This study attempts to discover whether the estimated economic impacts of contamination or noxious activity differ according to these characteristics of the studies, and whether anything general can be said about the economic consequences of site contamination and remediation. Bivariate, multivariate, and logit techniques are applied to the data. The results suggest that the property value is the most sensitive to water base contamination, published case studies result in systematically greater environmental value than those in unpublished reports, and real estate markets show responses to environmental condition changes.

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High-Sensitive Fiber-Optic pH Sensor Using Neutral Red Immobilized in Porous Sol-Gel Film (뉴트럴레드가 고정화된 다공성 졸-겔 필름을 이용한 고감도 광섬유 pH 센서의 특성)

  • Jeon, Da-Yeong;Yoo, Wook-Jae;Shin, Sang-Hun;Han, Ki-Tek;Park, Jang-Yeon;Park, Byung-Gi;Cho, Seung-Hyun;Lee, Bong-Soo
    • Journal of Sensor Science and Technology
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    • v.21 no.3
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    • pp.223-228
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    • 2012
  • In this study, a fiber-optic pH sensor based on a pH sol-gel film is fabricated. The sol-gel film is made by co-polymerizing tetramethoxysilane, trimethoxymethylsilane, ethanol and distilled water. As a pH indicator, a neutral red is immobilized in a thin porous film formed by the sol-gel process. The pH change in a sensing probe gives rise to a change in the color of the pH sol-gel film, and the absorbance of reflected light through the pH sol-gel film is also changed. By using a spectrometer, therefore, the spectra of reflected lights in the sensing probe with different pH values are measured. Also, the relationships between the pH values and the absorbance are analyzed on the basis of the color variations of the pH sol-gel films. In repeated experiments, the fiber-optic pH sensor shows that it has reversibility, a high reproducibility and a wide absorbance change in a pH range from pH 5 to 9. Also, we confirmed that the fabricated pH sol-gel film exhibits a fast response time, little or no pH indicator leaching and a dynamic range of 2.04 dB from pH 5 to 9. Based on the results of this study, a fiber-optic pH sensor can be developed for the pH monitoring in the harsh environments.