• Asian-Australasian Journal of Animal Sciences
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• v.19 no.2
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• pp.273-279
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• 2006

The performance of an autothermal thermophilic aerobic digestion (ATAD) system was studied to determine if nitrogen loss, as ammonia, was affected by an exhaust gas condenser. The system was run with and without a condenser while treating $8m^3$ of piggery slurry for 8 days. The system with a condenser (SWC) maintained the reactor temperatures above $40^{\circ}C$ for 2 days during the 8 days run, while the system without a condenser (SWOC) remained above $40^{\circ}C$ for 6 days. The SWC maintained the reactor temperatures mostly at mesophilic conditions while the SWOC at thermophilc conditions. Differences in operation conditions for the two runs were mainly caused by differences in atmospheric temperatures. Soluble chemical oxygen demand (SCOD) and volatile solids (VS) removal efficiencies of the SWC (SCOD: 62%, VS: 41%) were higher than those of the SWOC (SCOD: 40%, VS: 20%). The total Kjeldal nitrogen (TKN) removal efficiency of the SWC (7%) was less than that of the SWOC (25%). The concentration of total volatile fatty acids (VFA) in the SWC was observed to be lower than the threshold value of 0.23 g total VFA/L after 6 days, while the SWOC progressed below the threshold value after 3 days. No offensive odor emissions were observed in either run, which suggest that the use of the ATAD system may be a good odor removal strategy.

• Journal of Periodontal and Implant Science
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• v.52 no.6
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• pp.509-521
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• 2022

Purpose: Systemic health has a profound effect on dental treatment. The aim of this study was to evaluate peri-implant bone loss and health screening data to discover factors that may influence peri-implant diseases. Methods: This study analyzed the panoramic X-rays of patients undergoing health screenings at the Health Promotion Center at Seoul St. Mary's Hospital in 2018, to investigate the relationship between laboratory test results and dental data. The patients' physical data, such as height, weight, blood pressure, hematological and urine analysis data, smoking habits, number of remaining teeth, alveolar bone level, number of implants, and degree of bone loss around the implant, were analyzed for correlations. Their associations with glycated hemoglobin, glucose, blood urea nitrogen (BUN), creatinine, and severity of periodontitis were evaluated using univariate and multivariate regression analysis. Results: In total, 2,264 patients opted in for dental health examinations, of whom 752 (33.2%) had undergone dental implant treatment. These 752 patients had a total of 2,658 implants, and 129 (17.1%) had 1 or more implants with peri-implant bone loss of 2 mm or more. The number of these implants was 204 (7%). Body mass index and smoking were not correlated with peri-implant bone loss. Stepwise multivariate regression analysis revealed that the severity of periodontal bone loss (moderate bone loss: odds ratio [OR], 3.154; 95% confidence interval [CI], 1.175-8.475 and severe bone loss: OR, 7.751; 95% CI, 3.003-20) and BUN (OR, 1.082; 95% CI, 1.027-1.141) showed statistically significant predictive value. The severity of periodontitis showed greater predictive value than the biochemical parameters of blood glucose, renal function, and liver function. Conclusions: The results of this study showed that periodontal bone loss was a predictor of peri-implant bone loss, suggesting that periodontal disease should be controlled before dental treatment. Diligent maintenance care is recommended for patients with moderate to severe periodontal bone loss.

• Carbon letters
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• v.26
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• pp.66-73
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• 2018

We assessed the effects of combining bio-char with straw residue mulching on the loss of soil soluble nutrients and citrus yield in sloping land. The two-year study showed that straw residue mulching (ST) and bio-char application combined with straw residue (ST+BC) can significantly reduce soil soluble nutrient loss when compared with the control treatment (CK). The comparative volume of the soil surface runoff after each of the treatments was as follows: CK > ST > ST + BC. Compared with the CK, the runoff volume of the ST was reduced by 13.6 % and 8.5 % in 2014 and 2015, respectively. Compared with the CK, combining bio-char with the ST application reduced the loss of soluble nitrogen and improved the soil total nitrogen content reaching a significant level in 2015. It dramatically increased the soil organic matter content over the two year period (36.3% in 2014, 50.6% in 2015) as well as the carbon/nitrogen ratio (C/N) (16.6% in 2014 and 39.3% in 2015). Straw mulching combined with bio-char showed a trend for increasing the citrus yield.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.65-72
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• 2006

Experiments in methane-air low strain rate counterflow diffusion flames diluted with nitrogen have been conducted to study the behavior of flame extinction and edge flame oscillation in which flame length is less than the burner diameter and thus lateral conduction heat loss in addition to radiative heat loss could be remarkable at low global strain rates. Critical mole fraction at flame extinction is examined with velocity ratio and global strain rate. Onset conditions of edge flame oscillation and flame oscillation modes are also provided with global strain rate and added nitrogen mole fraction to fuel stream (fuel Lewis number). It is seen that flame length is closely relevant to lateral heat loss, and this affects flame extinction and edge flame oscillation considerably. Edge flame oscillations in low strain rate flames are experimentally described well and are categorized into three: a growing oscillation mode, a decaying oscillation mode, and a harmonic oscillation mode. The regime of flame oscillation is also provided at low strain rate flames. Important contribution of lateral heat loss even to edge flame oscillation is clarified.

• Journal of Plant Biology
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• v.14 no.3
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• pp.43-46
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• 1971

Losses of nitrogenin the gaseous form were determined with closed systems in the filed under different vegetation types. Ammonia volatilization was greatest from the pine stand, and least from the sod stand, and was greatly reduced in all three sites in the rainy season due to the low temperature. There were only insignificant differences in the nitrogen dioxide volatilization from the soil of the three vegetation types. Losses of ammonia and nitrogen dioxide at various soil depth also showed little variation. Evidently the microbial activity responsible for the $NO_2$ loss was relatively unaffected by the changes in temperature and soil moisture content during the investigation.

• Journal of the Korean Ceramic Society
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• v.38 no.7
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• pp.602-607
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• 2001

Zirconia powder containing 3 mol% yttria (3Y-PSZ) was casted on the cast iron substrate by plasma spraying method. Coated specimens were then heat treated at 500$\^{C}$ in nitrogen plasma. Wear tests were performed on nitrogen heat treated and non heat treated samples at temperatures from 25$\^{C}$ to 600$\^{C}$. Wear results showed that the friction coefficient and the wear loss of both the treated and the non-treated samples showed maximum value at 400$\^{C}$. These results were explained by low temperature thermal degradation due to the monoclinic transformation. Nitrogen plasma treatment significantly improved the tribological performance. The effect of nitrogen heat treatment on tribological behavior was explained by the increased micro-hardness and decreased monoclinic faction.

• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.54-70
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• 2017

The accumulator is a passive safety injection device for emergency core cooling systems. As an important safety feature for providing a high-speed injection flow to the core by compressed nitrogen gas pressure during a loss-of-coolant accident (LOCA), the accumulator injects its precharged nitrogen into the system after its coolant has been emptied. Attention has been drawn to the possible negative effects caused by such a nitrogen injection in passive safety nuclear power plants. Although some experimental work on the nitrogen injection has been done, there have been no comparative tests in which the effects on the system responses and the core safety have been clearly assessed. In this study, a new thermal hydraulic integral test facility-the advanced core-cooling mechanism experiment (ACME)-was designed and constructed to support the CAP1400 safety review. The ACME test facility was used to study the nitrogen injection effects on the system responses to the small break loss-of-coolant accident LOCA (SBLOCA) transient. Two comparison test groups-a 2-inch cold leg break and a double-ended direct-vessel-injection (DEDVI) line break-were conducted. Each group consists of a nitrogen injection test and a nitrogen isolation comparison test with the same break conditions. To assess the nitrogen injection effects, the experimental data that are representative of the system responses and the core safety were compared and analyzed. The results of the comparison show that the effects of nitrogen injection on system responses and core safety are significantly different between the 2-inch and DEDVI breaks. The mechanisms of the different effects on the transient were also investigated. The amount of nitrogen injected, along with its heat absorption, was likewise evaluated in order to assess its effect on the system depressurization process. The results of the comparison and analyses in this study are important for recognizing and understanding the potential negative effects on the passive core cooling performance caused by nitrogen injection during the SBLOCA transient.

• Korean Journal of Environmental Biology
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• v.39 no.2
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• pp.218-224
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• 2021

This study was conducted to determine the mass-loss rates and the changes in carbon/nitrogen (C/N) ratio of dead woods, which were of following species: Dryobalanops aromatic, D. rappa, and Cratoxylum arborescens. These were dominant tree species in mixed Dipterocarp forests (MDF) and peat swamp forests (PSF) in Brunei Darussalam. In May, 2019, 48 dead wood samples (15 cm×4.8 cm×5 cm) were placed in MDF and PSF sites, and all the samples were collected after 16 months. The effects of species on mass loss were statistically significant (p<0.05); however, no difference was observed in the mass loss obtained from the two forest types (p>0.05). The initial density (g·cm^-3) of the dead woods D. aromatic, D. rappa, and C. arborescens, was 0.64±0.02, 0.60±0.00, and 0.44±0.01, respectively. Also the annual mass loss rate (%) was estimated to be 6.37, 8.17, and 18.53 for D. aromatic, D. rappa, and C. arborescens, respectively. The proportion of dead woods in decay class III was only 25% of C. arborescens samples, which were attacked by wood-feeding invertebrates, such as termites. The C/N ratio decreased significantly in D. aromatic and D. rappa, but the decreasing trend of C/N ratio was not statistically significant in C. arborescens. The results indicate that physical traits of dead woods, such as density, could be one of the main factors causing the decomposition of dead woods initially, as invertebrates such as termites are one of the key decomposers of dead wood in tropical rainforests. In the samples of C. arborescens, which was attacked by invertebrates, nitrogen immobilization occurred to lesser extent as compared to that observed in D. aromatic and D. rappa.

• Korean Journal of Community Nutrition
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• v.2 no.4
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• pp.523-529
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• 1997

This study was conducted to obtain accurate data on the intake, digestibility and nitrogen balance of protein in Korean college women. Subjects were 8 female college students, aged from 21 to 23, and maintained their menu and life patterns regular during a 4- week study. The same amount of diet that the subjects had consumed, and feces and urine were collected and measured to extract their nitrogen content by Kjeldahl method. From this data, apparent digestibility and the body nitrogen balance were estimated by determing daily protein intake and excretion. The daily protein intake was 56.9$\pm$1.4g and daily fecal protein loss was 6.3$\pm$0.2g. The apparent digestibility of protein was 89.6$\pm$0.7$\%$. The daily nitrogen intake measured by Kjeldahl method was 9.43$\pm$0.2g. The urinary nitrogen excretion was 7.64$\pm$0.23g and fecal nitrogen excretion was 1.02$\pm$0.03g. The nitrogen balance indicated a positive balance of 0.45$\pm$0.18g. (Korean J Community Nutrition 2(4) : 523-529, 1997)

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.3
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• pp.37-42
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• 2018

The use of fly ash in construction materials is increasing worldwide due the various advantages of using it, such as to produce durable concrete, or to use less cement and thus lower carbon dioxide emissions. The quality of fly ash is often determined by loss on ignition value (LOI), where an upper limit of LOI is set in each country for quality control purpose. However, due to many reasons, production of high LOI fly ash is increasing that cannot be utilized in concrete, ending up in landfill. In this study, the effect of fly ash use in cementitious materials on nitrogen oxides adsorption is examined. In particular, the effect of using high LOI, and thus high carbon content fly ash on nitrogen oxides adsorption is investigated. The results suggest that the higher carbon content fly ash is related to higher nitrogen dioxide adsorption, although normal fly ash was also more effective in nitrogen dioxide adsorption than ordinary portland cement. Also, higher replacement rate of up to 40% of fly ash is beneficial for nitrogen dioxide adsorption. These results demonstrate that high carbon fly ash can be used as construction materials in an environmentally friendly way where strength requirement is low and where nitrogen oxides emissions are high.