• 한국토양비료학회지
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• 제12권2호
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• pp.109-116
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• 1979

Ammonia 가스를 $0.15mg/{\ell}$, $0.25mg/{\ell}$, $0.5mg/{\ell}$로 대두(大豆)의 영양생장기에 각(各) 1시간(時間)씩 접촉(接觸)시켰고, $0.2mg/{\ell}$의 Ammonia 가스를 1일중시각별(日中時刻別)로 06:00-07:00, 10:00-11:00, 14:00-15:00, 18:00-19:00, 22:00-23:00시(時)에 각각(各各) 1시간(時間)씩 접촉(接觸)시켜 대두(大豆)의 수량(收量), 피해증상, 피해엽율(被害葉率), 체내질소 및 엽록소 함량(含量)을 조사(調査)한 결과(結果)는 다음과 같다. 가. Ammonia 가스농도(濃度)가 증가함에 따라서 유의성(有意性)있는 피해엽율(被害葉率) 및 감수율증가를 가져왔고, 주간(晝間)에 접촉(接觸)한 것이 야간(夜間)에 접촉(接觸)한 것보다 감수(減收)가 컸다. 나. 피해엽율(被害葉率)과 수량간(收量間)에는 고도(高度)의 유의성(有意性) 있는 부(否)의 상관($r=-0.9553^{**}$)이 있었다. 다. $0.2mg/{\ell}$의 Ammonia 가스는 14:00-15:00시(時)에 접촉(接觸)한 것이 피해엽율(被害葉率)이 가장 컸으며 22:00~23:00시에 접촉(接觸)한 것이 가장 적었다. 라. Ammonia 가스농도증가에 따라 식물체내 전질소(全窒素) 및 수용성질소함량(水溶性窒素含量)은 증가하는 경향(傾向)이고 엽록소함량은 감소(減少)하는 경향(傾向)이었으며 엽록소 a는 b보다 감소정도(減少程度)가 컸다. 마. 체내질소함량은 오후(午後)에 접촉(接觸)한 것이 오전(午前)에 접촉(接觸)한 것보다 많았으며 엽록함량은 야간(夜間)에 접촉(接觸)한 것이 주간(晝間)에 접촉(接觸)한 것보다 많았다. 바. 엽록체의 Spectra는 10~11시(時)에 가장 감소(減少)가 컸고 22~23시(時)에 가장 감소(減少)가 적었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권5호
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• pp.316-322
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• 2002

A newly isolated heterotrophic marine bacterium, Vibrio alginolyticus, was used to remove a high load of ammonia gas under non-sterile condition. The cells were inoculated onto an inorganic packing material in a fixed-bed reactor (biofilter), and a high load of ammonia, in the range of ammonia gas concentration of 170 ppm to 880 ppm, was introduced continuously. Sucrose solution and 3% NaCl was supplied intermittently to supplement the carbon source and water to the biofilter. The average percentage of gas removed exceeded 85% for 107-day operation. The maximum removal capacity and the complete removal capacity were$19\;g-N\;kg^{-1}$ dry packing material $day^{-1}$ and $16\;g-N\;kg^{-1}$ dry packing material $day^{-1}$, respectively, which were about three times greater than those obtained in nitrifying sludge inoculated onto the same packing material. On day 82, the enhanced pressure drop was restored to the normal one by NaOH treatment, and efficient removal characteristics were later observed. During this operation, the non-sterile condition had no significantly adverse effect on the removability of ammonia by V. alginolyticus.

• 한국농공학회지
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• 제43권6호
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• pp.143-153
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• 2001

Hog manure amended with sawdust (moisture 56~60% wet basis, C/N 19-21) was composted in pilot-scale vessels using continuous aeration(CA) and intermittent aeration(IA) for 3 and 4 weeks. In two subsequent runs of the same duration, composts resulting from each of the first runs were used as a biofilter on the exhaust gas from newly composting material. Conditions between each of these paired sets appeared to be similar. Ammonia was released from the biofilter material during the first week of stabilization while the compost produced ammonia after the first week of composting. In both cases substantial absorption, 61~96 %, of ammonia production from the composting raw material was achieved in the stabilizing material during the final weeks of operation and indicates the use of the stabilizing hog manure/sawdust compost as a biofilter can reduce ammonia emissions. Total $NH_3-N$ emissions during run 2 in IA was less than 2/3 of those in CA. Dry solids loss for the stabilized compost (6~8 weeks) was 19~46%.

• 한국환경보건학회지
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• 제41권5호
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• pp.277-288
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• 2015

Objectives: There are many hazardous agents at livestock farms. In particular, gases can be detrimental to both workers and animals. This study evaluated ammonia and hydrogen sulfide concentrations in broiler hen barns and beef cattle barns according to sampling location and height. Methods: Three broiler hen barns and three beef cattle barns were selected for gas monitoring in this study. Ammonia and hydrogen sulfide concentrations were measured using a direct-reading instrument which could measure the target gases simultaneously. Gas monitoring was conducted at human breathing height and animal breathing height at three points in each livestock farm. Results: Ammonia concentrations at the broiler hen barns ranged from 3.3 to 12.5 ppm by sampling location and height, but hydrogen sulfide was not detected. In the beef cattle barns, ammonia ranged from 3.1 to 16.3 ppm and low concentrations of hydrogen sulfide were detected at some animal breathing heights. The gas concentrations detected at each livestock farm were significantly higher in the animal breathing zones than in human breathing zones (p<0.0001). Conclusions: We found a difference in gas concentrations between human breathing zones and animal breathing zones. Gas monitoring should be conducted to improve the related environment considering both workers' and animals' health and safety.

• 한국전기전자재료학회논문지
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• 제23권5호
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• pp.418-423
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• 2010

Carbon nanotubes (CNTs) were synthesized by Fe-catalytic chemical vapor deposition (CVD) method about $800^{\circ}C$. The influence of process parameters such as pretreatment conditions, gas flow ratio, processing time, etc on the growth of CNTs was investigated by field emission scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. Ammonia was added to acetylene source gas before and during the CNT growth. Different types of CNTs formed depending upon the processing condition. It was found that ammonia prevented amorphous carbons from adsorbing to the outer wall of CNT, resulting in purification of CNTs during CNT growth.

• 한국자동차공학회논문집
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• 제22권5호
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• pp.73-83
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• 2014

CFD(computational fluid dynamics) model is developed to simulate direct injection of ammonia gas phase from ammonia transporting materials into the SCR catalyst in the exhaust pipe of the engine with solid SCR. Configurations of one-hole and four-hole nozzle, circumferential type, porous tube type, and the effect of mixer configurations which commonly used in liquid injection of AdBlue are considered for complex geometries. Mal-distribution index related to concentration of ammonia gas, flow uniformity index related to velocity distribution, and pressure drop related to flow resistance are compared for different configurations of complex geometries at the front section of SCR catalyst. These results are used to design the injection system of ammonia gas phase for solid SCR of target vehicle.

• 한국세라믹학회지
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• 제51권3호
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• pp.201-207
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• 2014

High-purity aluminum nitride nanopowders were synthesized using an RF induction thermal plasma instrument. Ammonia and nitrogen gases were used as sheath gas to control the reactor atmosphere. Synthesized AlN nanopowders were characterized by XRD, SEM, TEM, EDS, BET, FTIR, and N-O analyses. It was possible to synthesize high-purity AlN nanoparticles through control of the ammonia gas flow rate. However, additional process parameters such as plasma power and reactor pressure had to be controlled for the production of high-purity AlN nanopowders using nitrogen gas.

• 한국농공학회지
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• 제45권2호
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• pp.107-115
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• 2003

Dairy manure amended with crop and forest residues (moisture 69% wet basis, C/N 22) was composted in a 605 L pilot-scale vessel using continuous air flow (56 L/min) for 19 days. Three pilot-scale sawdust biofilters (moisture 63%, pH 5.0) were built to clean biological waste gas from the composting process. For each methods, two replicated experiments were monitored over a period of three weeks. The system was evaluated to determine the biofilter media depth that would be adequate for compost odour reduction. The compost air cleaning was measured based on ammonia gas concentration before and after passing through the biofilter. Ammonia gas removal efficiency over 3 weeks was 42, 75 and 87% at sawdust biofilter media depth levels of 202, 400 and 600 mm, respectively. Each sawdust biofilter was operated at a moisture content in the range of 60~62% (wb), a temperature from 15 to $25^{\circ}C$, an average pressure drop from 240 to 340 Pa and a detention time from 60 to 180 seconds during the biofiltration process.

• 센서학회지
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• 제26권2호
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• pp.96-100
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• 2017

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been extensively studied as the active material in ammonia gas sensor because of its fast response time, high conductivity and environmental stability. It is well known that a post annealing process for organic devices based on PEDOT:PSS significantly increases the device performance. In this study, we propose the solvent annealing of PEDOT:PSS and investigated its effects. As a results, post solvent annealing on PEDOT:PSS lead to the surface chemical and physical properties change. These changes result in improved conductivity of the PEDOT:PSS. In additional, ammonia sensitivity of solvent annealed PEDOT:PSS become higher than pristine polymer film. The enhancement is mainly caused by the depletion of gas barrier PSS and structural re-forming PEDOT networks. We believe that the post solvent annealing is a promising method to achieve highly sensitivity PEDOT:PSS films for applications in efficient, low-cost and flexible ammonia gas sensor.

• 한국물환경학회지
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• 제26권5호
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• pp.732-739
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• 2010

Two combined autothermal thermophilic aerobic digestion (ATAD) and biofilter (BF) systems were operated to treat the piggery wastewater and the ammonia offgas. Experimental results indicated that the organic removal efficiency of ATAD-2, operated with oxygen, was higher than that of ATAD-1, operated with air. The concentration of ammonia in ATAD-2 offgas was higher compared to ATAD-1 offgas, but the total amount of ammonia produced from ATAD-2 was less than that from ATAD-1 due to the lower oxygen flowrate. The ammonia gas produced from both ATAD reactors was successfully removed by the BF. The BF-1, connected with ATAD-1, removed 93% of ammonia at the loading rate of $9.4g\;NH_3-N/m^3/hr$. The BF-2, connected with ATAD-2, removed 95% of ammonia gas at the loading rate of $8.1g\;NH_3-N/m^3/hr$. As the nitrification process continued, pH value of recirculating solution continuously decreased due to the accumulation of nitrate. When the ammonia loading rate was less than $22.7g\;NH_3-N/m^3/h$, the proper replacing cycle of recirculating solution was in the range of 10 to 11 days. Almost 90% of total mass of nitrogen fed into the each BF was confirmed from the mass balance on nitrogen.