• Journal of Microbiology and Biotechnology
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• 제22권2호
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• pp.270-273
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• 2012

These studies were conducted to determine the effects of various concentrations of ammonium and nitrate on current generation using dual-cathode microbial fuel cells (MFCs). Current generation was not affected by ammonium up to $51.8{\pm}0.0$ mg/l, whereas $103.5{\pm}0.0$ mg/l ammonium chloride reduced the current slightly. On the other hand, when $60.0{\pm}0.0$ and $123.3{\pm}0.1$ mg/l nitrate were supplied, the current was decreased from $10.23{\pm}0.07$ mA to $3.20{\pm}0.24$ and $0.20{\pm}0.01$ mA, respectively. Nitrate did not seem to serve as a fuel for current generation in these studies. At this time, COD and nitrate removal were increased except at $123{\pm}0.1$ mg ${NO_3}^-/l$. These results show that proper management of ammonium and nitrate is very important for increasing the current in a microbial fuel cell.

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권3호
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• pp.14-24
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• 2021

Aquifer thermal energy storage (ATES) system uses groundwater thermal energy for cooling and heating of buildings, and it is also often utilized to provide warm water to crops and plants for the purpose of enhancing agricultural yields. This study investigated the potential influences of a ATES system on the geochemical properties of groundwater by simulating the variation of hydrochemistry and saturation index of groundwater during ATES operation. The test bed was installed at an agricultural field, which is mainly composed of an groundwater-rich alluvial plain. The simulation results showed no significant precipitation of mineral phases such as manganese-iron oxide, carbonate and sulfate around the ATES test bed, as well as no debasement of other important water quality parameters. The implementation of ATES system in the study area was appropriate and effective for utilizing the thermal energy of groundwater for agricultural use.

• Asian-Australasian Journal of Animal Sciences
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• 제29권7호
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• pp.1004-1012
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• 2016

This experiment was conducted to investigate the effects of dietary energy levels on the physiological parameters and reproductive performance of gestating first parity sows. A total of 52 F1 gilts ($Yorkshire{\times}Landrace$) were allocated to 4 dietary treatments using a completely randomized design. Each treatment contained diets with 3,100, 3,200, 3,300, or 3,400 kcal of metabolizable energy (ME)/kg, and the daily energy intake of the gestating gilts in each treatment were 6,200, 6,400, 6,600, and 6,800 kcal of ME, respectively. During gestation, the body weight (p = 0.04) and weight gain (p = 0.01) of gilts linearly increased with increasing dietary energy levels. Backfat thickness was not affected at d110 of gestation by dietary treatments, but increased linearly (p = 0.05) from breeding to d 110 of gestation. There were no significant differences on the litter size or litter birth weight. During lactation, the voluntary feed intake of sows tended to decrease when the dietary energy levels increased (p = 0.08). No difference was observed in backfat thickness of the sows within treatments; increasing energy levels linearly decreased the body weight of sows (p<0.05) at d 21 of lactation and body weight gain during lactation (p<0.01). No significant differences were observed in the chemical compositions of colostrum and milk. Therefore, these results indicated that high-energy diets influenced the bodyweight and backfat thickness of sows during gestation and lactation. NRC (2012) suggested that the energy requirement of the gestation gilt should be between 6,678 and 7,932 kcal of ME/d. Similarly, our results suggested that 3,100 kcal of ME/kg is not enough to maintain the reproductive performance for gilts during gestation with 2 kg feed daily. Gilts in the treatment 3,400 kcal of ME/kg have a higher weaning number of piglets, but bodyweight and backfat loss were higher than other treatments during lactation. But bodyweight and backfat loss were higher than other treatments during lactation. Consequently, an adequate energy requirement of gestating gilts is 6,400 kcal of ME/d.

• Asian-Australasian Journal of Animal Sciences
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• 제28권10호
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• pp.1488-1495
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• 2015

This study was conducted to investigate the effects of post-harvest storage duration and wheat variety on the digestibility and energy content of new season wheat fed to finishing pigs. Two wheat varieties (Shi and Zhong) were harvested in 2013 and stored in the warehouse of the Fengning Pig Experimental Base at China Agricultural University for 3, 6, 9, or 12 mo. For each storage period, 12 barrows were placed in metabolism crates and allotted to diets containing 1 of the 2 wheat varieties in a randomized complete block design. The experimental diets contained 97.34% wheat and 2.66% of a vitamin and trace mineral premix. With an extension of storage duration from 3 mo to 12 mo, the gross energy (GE) and crude protein (CP) of the wheat decreased by 2.0% and 12.01%, respectively, while the concentration of neutral detergent fiber (NDF), acid detergent fiber (ADF) and starch content increased by 30.26%, 19.08%, and 2.46%, respectively. Total non-starch polysaccharide, total arabinose, total xylose and total mannose contents decreased by 46.27%, 45.80%, 41.71%, and 75.66%, respectively. However, there were no significant differences in the chemical composition between the two wheat varieties with the exception of ADF which was approximately 13.37% lower in Shi. With an extension of storage duration from 3 mo to 12 mo, the digestible energy (DE), metabolizable energy (ME) content and the apparent total tract digestibility of GE, CP, dry matter, organic matter, ether extract, ADF and metabolizability of energy in wheat decreased linearly (p<0.01) by 5.74%, 7.60%, 3.75%, 3.88%, 3.50%, 2.47%, 26.22%, 27.62%, and 3.94%, respectively. But the digestibility of NDF changed quadratically (p<0.01). There was an interaction between wheat variety and storage time for CP digestibility (p<0.05), such that the CP digestibility of variety Zhong was stable during 9 mo of storage, while the CP digestibility of variety Shi decreased (p<0.05). In conclusion, the GE, DE, and ME of wheat was stable during the first 3 to 6 mo of post-harvest storage, and decreased during the following 6 to 12 mo of storage under the conditions of this study.

• 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.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.877-885
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• 1993

Three types of solar grain dryers, namely , the solar grain bin dryer, the solar greenhouse rotary drum dryer and small scale solar green house tray dryer, have been tested. The results showed that each type of solar grain dryer has its feature. These solar drying units have three main advantages : (1) Required commercial energy to remove 1Kg moist from rough rice is only 5.3% to 15.8% of the energy consumed by common heated dryer : 2) The area of solar drying system is only about 10% of the area of the sunny ground to give equal drying capacity ; (3) There are good drying quality in the moisture uniform , germination percentage, and grain color.

• 에너지공학
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• 제27권3호
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• pp.10-20
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• 2018

저렴한 농사용 전력 요금으로 인한 농업 부문 전력 과소비, 에너지의 전력 의존도 증가, 전력 생산성 저하, 교차보조의 증가 등 부작용들이 심화되고 있다. 더구나, 저렴한 전기 요금의 혜택이 영세농이 아닌 기업농에 집중되고 있으며, 최근에는 가상통화 채굴에 농사용 전기가 불법 사용되는 사례가 늘고 있다. 본 연구는 이러한 부작용을 분석하고, 로그평균 디비지아 지수법(LMDI)을 이용하여 1988-2016년 농사용 전력 소비량 증가를 성장, 구조 변화, 에너지 집약도 변화 등 세 가지 요인으로 구분하여 각 요인별 영향을 추정한다. 본 연구는 현행 농사용 전력요금 정책이 여러 가지 부작용을 낳고 국가 에너지 수입 부담을 가중시키며 온실 가스 배출 증가 억제에 부정적인 만큼 근본적인 변화가 시급함을 알려준다.

• Asian-Australasian Journal of Animal Sciences
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• 제30권6호
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• pp.849-856
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• 2017

Objective: The net energy requirement for the maintenance ($NE_m$) of broilers was determined using regression models by the indirect calorimetry method (ICM) or the comparative slaughter method (CSM). Methods: A $2{\times}4$ factorial arrangement of treatments including the evaluation method (ICM or CSM) and feed intake (25%, 50%, 75%, or 100% of ad libitum recommended) was employed in this experiment. In the ICM, 96 male Arbor Acres (AA) birds aged d 15 were used with 4 birds per replicate and 6 replicates in each treatment. In the CSM, 116 male AA birds aged d 15 were used. Among these 116 birds, 20 were selected as for initial data and 96 were assigned to 4 treatments with 6 replicate cages and 4 birds each. The linear regression between retained energy (RE) and metabolizable energy intake (MEI) or the logarithmic regression between heat production (HP) and MEI were used to calculate the metabolizable or net energy requirement for maintenance ($ME_m$) or $NE_m$, respectively. Results: The evaluation method did not detect any differences in the metabolizable energy (ME), net energy (NE), and NE:ME of diet, and in the MEI, HP, and RE of broilers. The MEI, HP, and RE of broilers decreased (p<0.01) as the feed intake decreased. No evaluation method${\times}$feed intake interaction was observed on these parameters. The $ME_m$ and $NE_m$ estimated from the linear relationship were 594 and 386 kJ/kg of body weight $(BW)^{0.75}/d$ in the ICM, and 618 and 404 kJ/kg of $BW^{0.75}/d$ in the CSM, respectively. The $ME_m$ and $NE_m$ estimated by logarithmic regression were 607 and 448 kJ/kg of $BW^{0.75}/d$ in the ICM, and were 619 and 462 kJ/kg of $BW^{0.75}/d$ in the CSM, respectively. Conclusion: The NEm values obtained in this study provide references for estimating the NE values of broiler diets.

• 생물환경조절학회지
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• 제30권4호
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• pp.377-382
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• 2021

참외는 줄기를 땅 위에서 포복재배로 유인하는 것이 일반적으로써 노동강도가 강해서 농업인 근골격계 질환의 원인이 되므로 작업강도를 낮추고 품질도 향상시키기 위한 새로운 재배 방법을 찾고자 본 실험을 수행하였다. 그 결과, 줄기를 상향으로 유인하는 처리구가 생육 및 광합성 특성이 좋았고, 근활력은 하향 줄기 유인 처리구에서 좋은 것으로 나타났다. 상품 수량에 있어서는 상향 처리구가 4.055kg/10a, 하향 처리구가 3,983kg/10a으로 통계적인 유의성은 없었다. 줄기유인 작업에 대한 작업자세 평가의 경우, 기존 포복재배가 상향, 하향 재배방식 보다 위험수준이 높은 것으로 평가되었다. 결론적으로, 참외 수경 수직재배는 작물 생육, 수확량 및 작업 노동강도 등을 고려해 볼 때 기존 포복재배 방식을 대체할 수 있는 새로운 재배방법이라고 판단되고, 참외 줄기 유인 방법별로 수량 등에 유의성이 없으므로 상향 줄기유인 방법이나 하향 줄기 유인방법 중에서 하우스의 구조나 재배자의 의향에 따라서 선택하여 수직재배를 하면 될 것으로 사료된다.

• 한국지역사회생활과학회지
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• 제22권4호
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• pp.669-678
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• 2011

The purpose of this study were to analyze the staple food consumption trend of Koreans using KNHANES(Korea National Health and Nutrition Examination Survey) data. Nutrient intake of 38,840 participants of 1998~2008 KNHANES, over 6 year old were analyzed. For the analysis of major staple food intakes, twenty four hour recall data was used. The results were analyzed by SAS Program, as follows. Despite westernized diet, ranking in the primary energy source of food showed similar patterns. But total calory intake was reduced over the past 11 years and percentage of carbohydrate intake was increased. Relative proportions of protein and fat intake was reduced. The major carbohydrate and protein source of Koreans was rice and grains. Pork and ramen were the major fat source food. Although intake levels were different by gender, age and areas, carbohydrate of rice was primary source of energy in Korea.