• Membrane Journal
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• v.22 no.4
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• pp.251-257
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• 2012

For the separation and recovery of n-pentane from nitrogen environment, the poly (dimethyl siloxane) (PDMS) composite membranes supported by polyetherimide (PEI) hollow fiber membranes were prepared. To characterize the gas separation properties of the resulting membranes, the permeance of n-pentane and nitrogen, concentrations of permeate and retentate, and recovery ratio were measured for n-pentane and nitrogen mixtures. The permeance of n-pentane and nitrogen, 2485.3 and 9.9 GPU, were observed respectively. As the stage cut decreases and the feed concentration increases, the n-pentane concentration in permeate tends to increase. In the meanwhile, the recovery efficiency tends to increase as the stage cut increases and the feed concentration decreases.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.1
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• pp.64-70
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• 2001

To verify the newly developed decision assisting expert system for nitrogen fertilizer application NES to Illinois cornfields, a couple of N rate studies from Dr. Howard and five Illinois Agricultural Experiment Stations were applied. Four types of recommendations including the current Illinois recommendation, Hoeft recommendation, NES, and maximum economic recommendation were compared with each other for the crop yields, profits, recovery rate, and N losses to cornfields. The N rate of NES recommendation, considering productivity index (PI), soil organic matter content (SOM), and pre-sidedressing nitrate concentration (PSNT) level, was the lowest in comparison to those of other recommendations. However, N recovery rate in NES was generally higher and the resulting N loss was lower than others. But, adherence to the recommendations may also reduce farmers income if environmental expense did not considered. Therefore, NES will be more effective by adding the factors including environmental expense, tillage systems, crop rotation, and other agricultural management parameters.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.4
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• pp.253-259
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• 1996

Ammonia microdiffusion method and colorimetric measurement are described for the nitrogen determination. The diffusion of ammonia could be successfully induced by using a microdiffusion cell. It is a simple and rapid technique, which is suitable for transforming the nitrogen in digests into $NH_4CI$ for the colorimetric N determination with ammonia color reagent. Above 99% of N recovery were obtained with microdiffusion up to 15 hours. The coloration method of collected $NH_4CI$ for the colorimetric N determination was also estabilshed with a scanning in U.V. spectrophotometer. Under the proposed coloration method (0.5 mL of sample digest, 4.0 mL of $H_2O$ and 0.5 mL of ammonia color reagent), a maximal absorbance was observed at 410 nm. The kinetic measurement of absorbance showed a high stability from 5 to 45 minutes after color development. Absorbance was directly proportional to the amount of $NH_4^+-N$ present. The microdiffusion-ammonia coloration method was successfully applied to the nitrogen determination in the forms of protein-N or total -N in plant tissue. Comparing with Kjeldahl distillation method, the values obtained with described method were slightly higher and more reliable.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.1
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• pp.37-46
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• 2021

Nitrogen and phosphorus in livestock manure are environmental pollutants, but also could be valuable industrial resources. In the present study, we (1) introduced various nitrogen removal technologies such as stripping, thermal method, membrane, and electrodialysis, (2) reviewed relevant studies reported in 2011-2020, in particular, full-scale experiences, and (3) assessed each technologies based on the above survey results. In addition, we provided the information on the appropriate range of the pH, temperature, gas and liquid ratio, and so on in ammonia stripping process, and expected mass balance when it is connected to biogasification process. We hope the content herein can be helpful for making policy and operating full-scale plant in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.66-71
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• 1982

Field experiments of nitrogen application (0, 100, 200, 400, 800kg N/ha year) were carried out to study the nitrogen response of Sudangrass at College Farm, Seoul National Univ., in 1979 and 1980. Dry matter yield and leaf area index increased up to 400kg N/ha in 1979 and 800kg N/ha in 1980. The forage yield of 1980 was less than that of 1979, due to the extraordinarily low temperature and the decreased solar radiation during summer. Total nitrogen contents in forage increased with nitrogen application, but maximum contents were found either 400 or 800kg N levels depend on each cutting stages. Nitrate nitrogen content in forage exceded over 2000 ppm at 800kg N application. Overall percentages of N recovery were below 50% with average 34%. Net assimilation rate and nitrogen use efficiency of Sudangrass were improved in higher temperature and more sunlight condition during regrowth period.

• Environmental engineer
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• s.175
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• pp.70-75
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• 2001

산업용 보일러에 대해 오일버노에서 가스버너로 설비교체를 하면서 폐열회수, 저공기비 운전 등을 통해 열효율이 6$\~$8$\%$ 정도 향상되었으며 fuel NO의 제거로 질소산화물질은 1/3정도 배출되었다. 지구온난화 물질인 이산화탄소의 배출도 에너지 절감을 통해 6$\~$8$\%$ 정도 절감되었다. 이러한 결과는 국내 산업용 보일러의 효율향상 및 성능개선에 대한 분석적인 적용

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.3
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• pp.109-113
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• 1980

Organic bases in the dorsal meat of wild common carp, Cyprinus carpio, were analyzed as a part of the studies on the taste compounds of fresh-water fishes. The male and female meat showed no significant differences in contents of total creatinine, betaine, TMA and TMAO. The most abundant basic compound was total creatinine $(ca.\;400mg\%)$. The amount of betaine was poor $(ca.\;66.5mg\%)$ and TMA and TMAO were trace in content $(below\;1mg\%)$.

• Journal of Korean Society of Forest Science
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• v.77 no.4
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• pp.361-370
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• 1988

This study was carried out for observation of growth, mycorrhizal formation and nutrient absorption of Pinus thunbergii seedlings treated with two soil mixtures and various nitrogen levels after inoculation with mycorrhizal fungus, Pisolithus tinctorius. 1. Seedlings grown on vermiculite applied with $50-150{\mu}g/ml$ nitrogen levels were well developed with pinnate type and cluster-like mycorrhizae. But seedlings on sandy loam had monopodial type in addition to the above-mentioned two types. 2. Optimum fertilization level for mycorrhizal formation is 50 or $150{\mu}g/ml$ N that showed best mycorrhizal formation of $86.4({\pm}3.14)%$ or $73.0({\pm}7.21)%$, respectively, but increased nitrogen levels decreased formation of mycorrhizal short roots. Seedlings applied with $450{\mu}g/ml$ nitrogen level decreased in net assimilation rate (NAR) and crop growth rate(CGR) during early growth of the seedlings, and they were increased since Aug, when nutrient application was stopped. 9. Inorganic nutrient absorption was increased more in seedlings grown on vermiculite and inoculated growth medium than those grown on sandy loam and noninoculated one, and it was gradually increased with increasing nitrogen increasing nitrogen level until $350{\mu}g/ml$. But $450{\mu}g/ml$ nitro gen level rather reduced absorption of nutrient.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.124.1-124.1
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• 2011

저온 고압의 환경에서 안정한 하이드레이트 함유 퇴적물 연구를 위하여 현장의 압력을 유지하여 코어를 회수할 수 있는 압력 코어러 (Pressure Corer)가 개발된 이후로 다양한 방법으로 압력코어를 이용한 연구가 진행되어 왔다. 하이드레이트의 안정영역 특성상 일반 코어러 샘플에서는 하이드레이트 함유 퇴적물의 회수가 용이하지 않았던 이유로 압력코어샘플응 이용한 현장 하이드레이트 함유 퇴적물의 연구는 필수적이다. 초기 단계에서는 압력코어를 이용한 비파괴 검사와 단순 감압 시험이 이루어졌다. 비파괴 검사를 통하여서는 X-ray 단면, 감마 밀도 (gamma density), 음파 속도 등이 측정 되었으며 감암 시험을 통하여서는 시료 내 하이드레이트 함유량을 산정하였다. 감압 후 다양한 지화학 분석이 후행되었다. 가스 하이드레이트 함유 퇴적물의 물성과 생산 거동이 점차 부각됨에 따라 압력코어 시료를 순간 감압하여 액체 질소에 보관하였다가 압밀시험, 삼축 압축 시험 등 물성 시험이 수행되었으며 수행 동안 X-ray 단면, 비저항, 음파 속도 등의 물성측정이 이루어졌다. 또한 액체 질소 보관 시료를 이용하여 감압법, 열염수 주입법, 열자극 법 등을 적용하여 생산 실험을 수행하기도 하였다. 이후에 압력코어 시료 절단 및 이동 시스템이 개발됨에 따라 보다 다양하고 많은 연구자 들이 압력코어 시료를 이용할 수 있게 되었으며 물성 연구뿐만 아니라 미생물 연구에 까지 압력코어 시료가 사용되게 되었다. 최근에는 절단 시료를 이용한 생산 실험 연구 또한 진행되었다.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.308-312
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• 2012

BACKGROUND: The nutrient balance in Korea during 1985-2006 had continually increased and maintained the highest levels among OECD countries. The use of green manure crops such as barley and hairy vetch is common practice for reducing chemical fertilizer application and maintaining soil fertility. However, green manure crops can also be used as a livestock feeding material which may reduce nutrient balance in the national scale. We calculated nitrogen and phosphate balance under green manure-rice cultivating system where all green manure was removed and used for feeding livestock. METHODS AND RESULTS: The barley and hairy vetch grown in pure stands or in mixtures with different sowing rates were tested for rice cultivation without chemical fertilization. The conventional fertilization (NPK) for rice cultivation was selected to compare nutrient balance with green manure-rice cultivation. Nitrogen and phosphate balance were calculated according to the surface balance method of the PARCOM guidelines. Total aboveground biomass of mixture (barley and hairy vetch) was higher compared to that of pure barley or hairy vetch. Among the mixture with barley and hairy vetch, the highest aboveground biomass was observed in B75H25 (barley 75%+hairy vetch 25%). The nitrogen and phosphate balance in the B75H25 mixture was-104 kg N/ha and-50.3 kg P/ha, respectively. CONCLUSION(S): The barley and hairy vetch mixture proved to be a very effective strategy for biomass production of green manure. The amount of nitrogen and phosphate fertilizer to be applied is estimated to be 104 kg N/ha and 50.3 kg P/ha in order to maintain soil fertility if all green manure and rice straw were removed from rice field for livestock feeding.