• 제목/요약/키워드: Energy Content

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고온 고분자 전해질막 연료전지 수소극 전극에서 서로 다른 가스 확산층에 따른 최적 바인더 함량 결정 (Determination of Optimum Binder Content in the Catalyst Layer with Different GDL for Anode of HT-PEMFC)

  • 전현수;김도형;정현승;박찬호
    • 한국수소및신에너지학회논문집
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    • 제33권1호
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    • pp.38-46
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    • 2022
  • Two different gas diffusion layers having noticeable differences in micro-porous layer's (MPL's) crack were studied as a substrate for the gas diffusion electrode (GDE) with different binder/carbon (B/C) ratios in high-temperature polymer electrolyte fuel cell (Ht-PEMFC). As a result, the performance defined as the voltage at 0.2 A/cm2 and maximum power density from the single cells using GDEs from H23 C2 and SGL38 BC with different B/C ratios were compared. GDEs from H23 C2 showed a proportional increase of the voltage with the binder content on the other hand GDEs from SGL38 BC displayed a proportional decline of the voltage to the binder content. It was revealed that MPL crack influences the structure of catalyst layer in GDEs as well as affects the RCathode which is in close connection with the Ht-PEMFC performance.

The Effect of High Environmental Temperature and Nutrient Density on Pig Performance, Conformation and Carcass Characteristics under Restricted Feeding System

  • Hsia, L.C.;Lu, G.H.
    • Asian-Australasian Journal of Animal Sciences
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    • 제17권2호
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    • pp.250-258
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    • 2004
  • An experiment was conducted to examine the effect of a high environmental temperature on the performance, conformation, and carcass characteristics of pigs and the influence of diet. Thirty-six three-way crossed castrated male pigs with average initial body weight of 50.4 kg were used in the experiment. The pig were allocated to the following treatments: two environmental temperatures (20 and $30^{\circ}C$)${\times}$three dietary energy levels (2,980, 3,300 and 3,600 kcal/kg)${\times}$three protein levels (12.8, 15.2 and 17.2%). Daily weight gain was lighter (p<0.01) and feed: gain ratio lower (p<0.05) in pigs at $30^{\circ}C$ than for pigs at $20^{\circ}C$ The pigs at $30^{\circ}C$ were significantly taller with deeper bodies (p<0.05) and significantly longer (p<0.05) both vertically horizontally in the planum nasal when kept at $30^{\circ}C$. The width of body and the circumference of the neck were greater (p<0.05) at $20^{\circ}C$. The lean meat of the loin, middle section, ham, and hind section were significantly greater (p<0.05) in pigs kept at $30^{\circ}C$ and the belly was significantly heavier. The total unsaturated free fatty acids were significantly higher (p<0.05) in the body fat of pigs kept at $20^{\circ}C$ than in that of pigs at $30^{\circ}C$. The results indicated that when pigs are given very restricted same amounts of feed, they may need less energy to maintain their body temperature under moderately high environmental temperature ($30^{\circ}C$); consequently, their performance is better than that of pigs under optimum environmental temperature. The results showed very clearly that weight gain of pigs increased with increasing of dietary protein and energy content. The increasing of dietary protein content seemed more significant when content increasing to 17.2% compared with the 12.8 and 15.2% protein content treatments. The increasing of dietary energy content was more significant when content increasing to 3,600 compared with the other low energy content treatments.

바이오가스 정제 및 고질화 기술 현황 및 전망 (The Present and the Future of Biogas Purification and Upgrading Technologies)

  • 허남효;박재규;김기동;오영삼;조병학
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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    • pp.172-172
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    • 2011
  • Anaerobic digestion(AD) has successfully been used for many applications that have conclusively demonstrated its ability to recycle biogenic wastes. AD has been successfully applied in industrial waste water treatment, stabilsation of sewage sludge, landfill management and recycling of biowaste and agricultural wastes as manure, energy crops. During AD, i.e. organic materials are decomposed by anaerobic forming bacteria and fina1ly converted to excellent fertilizer and biogas which is primarily composed of methane(CH4) and carbon dioxide(CO2) with smaller amounts of hydrogen sulfide(H2S) and ammonia(NH3), trace gases such as hydrogen(H2), nitrogen(N2), carbon monoxide(CO), oxygen(O2) and contain dust particles and siloxanes. The production and utilisation of biogas has several environmental advantages such as i)a renewable energy source, ii)reduction the release of methane to the atomsphere, iii)use as a substitute for fossil fuels. In utilisation of biogas, most of biogas produced from small scale plant e.g. farm-scale AD plant are used to provide as energy source for cooking and lighting, in most of the industrialised countries for energy recovery, environmental and safety reasons are used in combined heat and power(CHP) engines or as a supplement to natural. In particular, biogas to use as vehicle fuel or for grid injection there different biogas treatment steps are necessary, it is important to have a high energy content in biogas with biogas purification and upgrading. The energy content of biogas is in direct proportion to the methane content and by removing trace gases and carbon dioxide in the purification and upgrading process the energy content of biogas in increased. The process of purification and upgrading biogas generates new possibilities for its use since it can then replace natural gas, which is used extensively in many countries, However, those technologies add to the costs of biogas production. It is important to have an optimized purification and upgrading process in terms of low energy consumption and high efficiency giving high methane content in the upgraded gas. A number of technologies for purification and upgrading of biogas have been developed to use as a vehicle fuel or grid injection during the passed twenty years, and several technologies exist today and they are continually being improved. The biomethane which is produced from the purification and the upgrading process of biogas has gained increased attention due to rising oil and natural gas prices and increasing targets for renewable fuel quotes in many countries. New plants are continually being built and the number of biomethane plants was around 100 in 2009.

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Characteristics of Fracture Energy on Steel Fiber-Reinforced Lightweight Polymer Concrete

  • Youn, Joon-No;Sung, Chan-Yong
    • 한국농공학회지
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    • 제45권7호
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    • pp.11-19
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    • 2003
  • In this study, unsaturated polyester resin, artificial lightweight coarse aggregate, artificial lightweight fine aggregate, heavy calcium carbonate and steel fiber were used to produce a steel fiber-reinforced lightweight polymer concrete with which mechanical properties were examined. Results of this experimental study showed that the flexural strength of unnotched steel fiber-reinforced lightweight polymer concrete increased from 8.61 to 13.96 MPa when mixing ratio of fiber content increased from 0 to 1.5%. Stress intensity factors($K_{IC}$) increased with increasing fiber content ratio while it did not increase with increasing notch ratio. Energy release rate ($G_{IC}$) turned out to depend upon the notch size, and it increased with increasing steel fiber content.

태양전지 모듈의 내구성을 위한 EVA sheet의 특성 연구 (A Study on EVA Sheet Characteristic for Photovoltaic Modules Durability)

  • 강경찬;강기환;허창수;유권종
    • 한국태양에너지학회:학술대회논문집
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    • 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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    • pp.30-35
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    • 2008
  • The purpose of EVA sheet in PV module is to bond or laminate the multiple layers of a module. We studied the influence of EVA sheet gel content on photovoltaic module durability. Gel Content was measured by manufacturing Glass/EVA Sheet/Back Sheet scheme at several curing temperature. Through this experiment, we could confirm that there are changes on Gel Content of EVA Sheet. The transmittance of $140^{\circ}C$/4min process condition was more excellent than the other condition at ultraviolet wavelength range. The thermal stability of $150^{\circ}C$/4min process condition was higher than the other condition.

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시판 지방성 가공식품의 지질함량과 지방산 조성(II) - 인스탄트 유탕면을 중심으로 - (Lipid Content and Fatty Acid Composition of Commercial Fatty Processed Food(II) -Fried Instant Noodle-)

  • 김정헌;김복순;박건용;김을상;이규한
    • 한국식품영양과학회지
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    • 제27권1호
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    • pp.35-37
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    • 1998
  • This study was performed to investigate lipid content, melting point, refractive index, fatty acid composition and energy intake from lipid of commercial fried instant noodles. Sixty five samples were collected in Seoul area, and analyzed. The average of lipid content was 16.7%, melting point and refractive index were 29$^{\circ}C$ and 1.46, respectively. The fatty acid composition mainly consisted of C16:0, C18:1 and C18:2. The ratio of P/M/S in fried instant noodles was 0.19 : 0.77 : 1.00. The average energy intake from lipid of 100g fried instant noodles was 150.3kcal.

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A Compilation and Evaluation of Thermal and Mechanical Properties of Bentonite-based Buffer Materials for a High- level Waste Repository

  • Cho, Won-Jin;Lee, Jae-Owan;Kang, Chul-Hyung
    • Nuclear Engineering and Technology
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    • 제34권1호
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    • pp.90-103
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    • 2002
  • The thermal and mechanical properties of compacted bentonite and bentonite-sand mixture were collected from the literatures and compiled. The thermal conductivity of bentonite is found to increase almost linearly with increasing dry density and water content of the bentonite. The specific heat can also be expressed as a function of water ontent, and the coefficient of thermal expansion is almost independent on the dry density. The logarithm of unconfined compressive strength and Young’s modulus of elasticity increase linearly with increasing dry density, and in the case of constant dry density, it can be fitted to a second order polynomial of water content. Also the unconfined compressive strength and Young’s modulus of elasticity of the bentonite-sand mixture decreases with increasing sand content. The Poisson’s ratio remains constant at the dry density higher than 1.6 Mg/m$_3$, and the shear strength increases with increasing dry density.

Energy Metabolism and Protein Utilization in Chicken- A Review

  • Kim, Ji-Hyuk
    • 한국가금학회지
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    • 제41권4호
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    • pp.313-322
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    • 2014
  • Evaluation of energy in the diet is very important in animal nutrition because food intake is strongly influenced by the energy content of the diet. This means that the intake of other nutrients, such as amino acids, is affected by their ratio to energy content. Poultry can control their energy intake over a range of energy: protein ratios. Energy: protein ratio also affects the growth and body composition. Therefore we need to know what extent the relationship between energy and dietary protein influences the bird's performance. To predict the energy value of the diet or its chemical constituents, researchers have been working on modelling using the equations of the major biochemical pathways in terms of ATP generation and utilization. The activity of feeding and the metabolism caused by digestion and assimilation of food increase the animal's heat production and it can be measured by calorimetry technique. Theoretically, surplus amino acids which are not needed for protein synthesis stimulate an additional increase in metabolic rate and lead to increased energetic costs of catabolism and excretion. However, it has sometimes been shown that there was no measurable diet-induced thermoregulatory effect when an imbalanced amino acid mixture was fed. All these aspects are discussed in this review.