• 한국수산과학회지
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• 제49권2호
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• pp.241-246
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• 2016

A filamentous green alga Cladophora vadorum (Areschoug) Kützing, bloomed at Shangrok Beach, Buan, Republic of Korea, in September 2015. This alga is currently distributed worldwide. Concentrations of total nitrogen (TN), total phosphorus (TP), dissolved inorganic nitrogen (DIN), and dissolved inorganic phosphorus (DIP) were analyzed in the bloom area and compared to those of other areas in the vicinity. DIN and DIP concentrations were similar to those of other areas. However, TN and TP were as much as six and ten times higher than in other areas, respectively. As in other Cladophora species, the bloom of C. vadorum at Shangrok Beach in 2015 appears to have depended on the TP concentration in the seawater. This suggests that blooms in the area can be controlled by reducing TP.

• The Korean Journal of Ecology
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• 제27권2호
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• pp.67-71
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• 2004

This study was carried out to evaluate soil carbon and nutrient storage of three adjacent coniferous plantations (Larix leptolepis, Pinus densiflora and Pinus rigitaeda) growing on a similar site with a same planting age (42-year old) in the Sambong Exhibition Forests, Hamyang-gun, Gyungsangnam-do. The soil carbon concentration among three plantations was not significantly different in 0∼10cm soil depth, but other two depths (10∼20cm and 20∼30cm) showed higher carbon concentration in P. densiflora plantation than the other two plantations. The exchangeable cation concentrations (Ca and Mg) in 0∼10cm depth were significantly lower in L. leptolepis plantation than in the other two plantations, while nitrogen and phosphorus concentrations were not significantly different among three plantations except for nitrogen at 10∼20cm depth in P. rigitaeda plantation. Soil carbon storage in 0∼20cm depth of three plantations was unaffected by the stand types. Soil nutrient storage was not significantly different at each depth except for nitrogen storage at 10∼20cm depth in P. rigitaeda plantation because of the variation of bulk density and coarse fragment. This result demonstrates that soil carbon and nutrient concentrations among the plantations on a similar soil condition can be altered significantly by tree species effects over 40 years after plantation establishment.

• 한국응용과학기술학회지
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• 제22권4호
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• pp.349-354
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• 2005

It is interesting to discover the reaction kinetics of the newly developed molybdenum containing catalysts. The dissociation/adsorption of nitrogen on molybdenum surface is known to be structure sensitive, which is similar to that of nitrogen on iron surface. The rates over molybdenum nitride catalysts are increased with the increase of total pressure. This tendency is the same as that for iron catalyst, but is quite different from that for ruthenium catalyst. The activation energies of the molybdenum nitride catalysts are almost on the same level, although the activity is changed by the addition of the second component. The reaction rate is expressed as a function of the concentration of reactants and products. The surface nature of $CO_3Mo_3N$ is drastically changed by the addition of alkali, changing the main adsorbed species from $NH_2$ to NH on the surface. The strength of $NH_x$ adsorption is found to be changed by alkali dopping.

• 신재생에너지
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• 제20권3호
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• pp.1-11
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• 2024

Livestock manure solid fuel has been studied as a promising domestic energy resource for reducing greenhouse gas emissions in agricultural fields. To successfully commercialize this technology, the environmental facilities require optimization in accordance with domestic environmental standards. In the present study, a computational analysis model of a livestock manure solid fuel boiler system was developed using Aspen Plus^® to investigate nitrogen oxides (NOx) emissions and NOx conversion efficiency using urea-based selective non-catalytic reduction (SNCR). All data were compared across different livestock species and simulated at various operating temperatures. The simulation showed that NOx emissions were the highest from chicken manure and the lowest from swine manure. However, when converted to an oxygen concentration of 12%, NOx emissions were the highest from cattle manure. Dominant factors influencing NOx emissions through a range of temperatures were analyzed, and the optimal operating temperature range (875-950℃) was derived.

• Journal of Korean Society for Atmospheric Environment
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• 제23권E2호
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• pp.47-56
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• 2007

Among all the nitrogen species present in the atmosphere, ammonia forms a considerable portion along with the nitrogen oxides. The major sources of atmospheric ammonia are animal feedlot operations including emission from excreta of domestic animals and agricultural activities, followed by emission from synthetic fertilizers, biomass burning and to some lesser extent, fossil fuel combustion. Ammonia emission factor, expressed as the weight of ammonia per unit weight, volume, or duration of the activity emitting it, is generally used in developing emission estimates for emission inventories. The factors determining ammonia loss from soil or from manures are the temperature, pH, humidity, precipitation and the velocity of wind above it.

• 대한기계학회논문집B
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• 제28권10호
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• pp.1279-1287
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• 2004

The vaporization characteristics of a liquid heptane droplet in a supercritical nitrogen flow are numerically studied. The transient conservation equations of mass, momentum, energy, and species are expressed in an axisymmetric coordinate system. The governing equations are solved time marching method with preconditioning scheme. The modified Soave-Redlich-Kwong equation of state is employed for taking account of real gas effects such as thermodynamic non-ideality and transport anomaly. Changing the convective velocity and ambient pressure, several parametric studies are conducted. The numerical results show that the two parameters, Reynolds number and dimensionless combined parameter(${\mu}$s/${\mu}$d)(equation omitted), have influence on supercritical droplet vaporization.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.171-174
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• 2003

Animal excreta is a useful fertilizer, because it has useful nourishments, microelements and three requistes of fertilizer(nitrogen, phosphorus, potassium). But, it has some problems such as generation of bad smell and excess of nitrogen. In this study, a biological tool using microorganisms was investingated. First, 61 species were isolated from soil sample. The enzyme activities of the strains such as protease, cellulase, amylase and lipase were analysed. And from a deodorization test using the isolated strains and finally three strains were selected(NA 2, NA 12, NA 15). The optimal media composition and incubation pH were statistically determined using surface-response method.

• 한국초지조사료학회지
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• 제12권4호
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• pp.239-245
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• 1992

Aspects of nitrate accumulation of forages growing on grasslands in Chonbuk Province, and the effects of different rates of N fertilizer on the total nitrogen and nitrate contents of sudangrass-hybrid and corn were studied through the 1991 growing season. The results obtained are summarized as follows: I . Thc nitrate content of the forages was increased by N application and decreased as the plants matured. 2. Nitrate concentration was high throughout the growing season in samples collected at Namweon-gun 1, which was considered as potentially unsafe. 3. Total nitrogen and nitrate content of plants generally increased with the increasing rates of N fertilizer, but not statistically significant among treatments except the plot of 25 kg N/lOa. 4. The annual crops had a greater tendency to accumulate nitrate than the perennial forage species. 5. It is suggested that high level of N fertilizer and manure may result in toxic levels of nitrate, and special attention must be given in feeding them.

• 한국전기전자재료학회논문지
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• 제14권10호
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• pp.835-844
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• 2001

In this paper, we report the successful growth of crystalline carbon nitride films in Si(100) by a laser-electric discharge method. The laser ablation of the target leads to vapor plume plasma expending into the ambient nitrogen arc discharge area. X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy(AES) were used to identify the binding structure and the content of the nitrogen species in the deposited films. The surface morphology of the films with a deposition time of 2 hours is studied using a scanning electron microscopy (SEM). In order to determine the structural crystalline parameters, X-ray diffraction (XRD) was used to analysis the grown films.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권6호
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• pp.546-551
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• 2005

[ ${\beta}-1,3-Glucan$ ] (curdlan) is a water-insoluble polysaccharide composed exclusively of ${\beta}-1,3\;linked$ glucose residues. Extracellular curdlan was mostly synthesized by Agrobacterium species and Alcaligenes faecalis under nitrogen-limiting conditions. In this study, we screened the microorganisms capable of producing extracellular curdlan from soil samples. For the first time, we reported Gram-positive bacterium Bacillus sp. SNC 107 capable of producing extracellular curdlan in appreciable amounts. The effect of different carbon sources on curdlan production was studied and found that the yield of curdlan was more when glucose was used as carbon source. It was also found that maximum production was achieved when the initial concentration of ammonium and phosphate in the medium was 0.5 and 1.9 g/L respectively. In this study the curdlan production was increased from 3 to 7g/L in shake flask cultures.