• 열처리공학회지
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• 제36권2호
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• pp.86-95
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• 2023

This paper explained the equipment and process development to secure the source technology of controlled nitrification technology. The nitriding potential in the furnace was controlled only by adjusting the flow rate of ammonia gas introduced into the furnace. In addition, a control system was introduced to automate the nitriding process. The equipment's hardware was designed to enable controlled nitriding based on the conventional gas nitriding furnace, and an automation device was attached. As a result of measuring the temperature and quality uniformity for the equipment, the temperature and compound uniformity were ±1.2℃ and 14.3 ± 0.2 ㎛, respectively. And, it was confirmed that nitriding potential was controlled within the tolerance range of AMS2759-10B standard. In addition to parts for controlled nitriding, it was applied to products produced in existing conventional nitriding furnaces, and as a result, gas consumption was reduced by up to 80%.

• Asian-Australasian Journal of Animal Sciences
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• 제28권2호
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• pp.188-199
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• 2015

Nineteen tanniferous browse plants were collected from South Africa to investigate their digestibility, gas production (GP) characteristics and methane production. Fresh samples were collected, dried in forced oven, and ground and analyzed for nutrient composition. In vitro GP and in vitro organic matter digestibility (IVOMD) were determined using rumen fluid collected, strained and anaerobically prepared. A semi-automated system was used to measure GP by incubating the sample in a shaking incubator at $39^{\circ}C$. There was significant (p<0.05) variation in chemical composition of studied browses. Crude protein (CP) content of the species ranged from 86.9 to 305.0 g/kg dry matter (DM). The neutral detergent fiber (NDF) ranged from 292.8 to 517.5 g/kg DM while acid detergent fiber (ADF) ranged from 273.3 to 495.1 g/kg DM. The ash, ether extract, non-fibrous carbohydrate, neutral detergent insoluble nitrogen, and acid detergent insoluble nitrogen and CP were negatively correlated with methane production. Methane production was positively correlated with NDF, ADF, cellulose and hemi-cellulose. Tannin decreased GP, IVOMD, total volatile fatty acid and methane production. The observed low methanogenic potential and substantial ammonia generation of some of the browses might be potentially useful as rumen manipulating agents. However, a systematic evaluation is needed to determine optimum levels of supplementation in a mixed diet in order to attain a maximal depressing effect on enteric $CH_4$ production with a minimal detrimental effect on rumen fermentation of poor quality roughage based diet.

• 한국유기농업학회지
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• 제12권1호
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• pp.81-92
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• 2004

The effect of feeding extracts from rhus trees on performance of broiler were performed to investigate development of natural antibiotic in process of broilers production. A total of 320 broiler chicks at 7 day of age were fed the commercial diet and water, water containing 0 ppm (control), 300 ppm (T1), 600 ppm (T2) and 1000 ppm (T3) of extracts from rims trees for 7 weeks. The body weight gain and feed conversion ratio were improvement by feeding extracts from rims trees at 7 to 21 days of age (P<0.05), but amount of feed intake and mortality were not different among the four group. When 21 to 35 days of age, body weight gain, amount of feed intake, feed conversion ratio and mortality were almost same results when 7 to 21days of age, but it was not significantly different. When 35 to 49 days of age, body weight gain in T1 and T3 group was significantly improvement than control group (P<0.05), also feed conversion ratio was improve by feeding extracts from rhus trees. There was a decrease in the microflora population of both E coli. and salmonella in the cecum contents and feaces in broilers by feeding extracts from rhus trees. Emission of ammonia and VFA gas from excreta were significantly decreased at 5 to 10 days of storaged period (P<0.05). The digestibility of dry matter, crude fat, and crude ash of feed were tend to increased in broiler feeding extracts from rims trees. Digestibility of crude protein of feed in broiler three treatmental groups was significantly improved (P<0.05) as compared with those in control group. These results indicated that the feeding extracts from rhus trees of 300 to 1000 ppm of broiler production were improvement in th6 body weight gain, feed conversion ratio, and mortality due to increasing nutrients digestibility from feed, decreasing of microflora population of both E coll. and salmonella in the cecum contents and feaces, decreasing emission of ammonia and VFA gas from excreta.

• 한국동물위생학회지
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• 제33권4호
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• pp.387-392
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• 2010

This experiment was conducted to investigate the effect of fermented spent mushroom substrate (FSMS) on growth performance, blood profile, intestinal microflora and ammonia gas production of feces in broiler chickens. A total of three hundred sixty, 1-day-old male broiler chicks (Ross) were randomly divided into 3 groups with 6 replicates of 20 birds each. The treatments were control (free FSMS), 15% FSMS (basal diet with 15% FSMS) and 30% FSMS (basal diet with 30% FSMS). The final body weight and body weight gains were slightly improved in 30% FSMS than control (P<0.05). Feed intake and feed conversion were significantly improved as compared to those of the control groups. The Leukocytes of blood serum in FSMS groups were significantly decreased as compared to those of control groups. There are no significant differences among the groups in the contents of albumin (ALB), total cholesterol (TCHO), glucose (GLU), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in blood serum. The content of total glucose (TG) in 30% FSMS containing dietary groups was significantly decreased as compared to that of the control groups. The content of HDLC in 30% FSMS containing dietary groups was significantly increased as compared to that of the control group. The number of lactobacillus in the intestinal microflora were significantly increased in chicks fed FSMS groups. The ammonia gas production in FSMS groups was siginificantly decreased as compard to that the control groups. These results indicated that dietary FSMS exerted growth performance for feeding broiler.

• Asian-Australasian Journal of Animal Sciences
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• 제25권1호
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• pp.86-91
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• 2012

An in vitro rumen batch culture study was completed to compare effects of common grasses, leguminous shrubs and non-leguminous shrubs used for livestock grazing in Australia and Ghana on $CH_4$ production and fermentation characteristics. Grass species included Andropodon gayanus, Brachiaria ruziziensis and Pennisetum purpureum. Leguminous shrub species included Cajanus cajan, Cratylia argentea, Gliricidia sepium, Leucaena leucocephala and Stylosanthes guianensis and non-leguminous shrub species included Annona senegalensis, Moringa oleifera, Securinega virosa and Vitellaria paradoxa. Leaves were harvested, dried at $55^{\circ}C$ and ground through a 1 mm screen. Serum bottles containing 500 mg of forage, modified McDougall's buffer and rumen fluid were incubated under anaerobic conditions at $39^{\circ}C$ for 24 h. Samples of each forage type were removed after 0, 2, 6, 12 and 24 h of incubation for determination of cumulative gas production. Methane production, ammonia concentration and proportions of VFA were measured at 24 h. Concentration of aNDF (g/kg DM) ranged from 671 to 713 (grasses), 377 to 590 (leguminous shrubs) and 288 to 517 (non-leguminous shrubs). After 24 h of in vitro incubation, cumulative gas, $CH_4$ production, ammonia concentration, proportion of propionate in VFA and IVDMD differed (p<0.05) within each forage type. B. ruziziensis and G. sepium produced the highest cumulative gas, IVDMD, total VFA, proportion of propionate in VFA and the lowest A:P ratios within their forage types. Consequently, these two species produced moderate $CH_4$ emissions without compromising digestion. Grazing of these two species may be a strategy to reduce $CH_4$ emissions however further assessment in in vivo trials and at different stages of maturity is recommended.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.540-540
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• 2013

In this studying, we investigated the basic properties of N-doped plasma polymer. The N-doped ethylcyclohexane plasma polymer thin films were deposited by radio frequency (13.56 MHz) plasma-enhanced chemical vapor deposition method. Ethylcyclohexenewas used as organic precursor (carbon source) with hydrogen gas as the precursor bubbler gas. Additionally, ammonia gas [NH3] was used as nitrogen dopant. The as-grown polymerized thin films were analyzed using ellipsometry, Fourier-transform infrared [FT-IR] spectroscopy, Raman spectroscopy, FE-SEM, and water contact angle measurement. The ellipsometry results showed the refractive index change of the N-doped ethylcyclohexene plasma polymer film. The FT-IR spectrashowed that the N-doped ethylcyclohexene plasma polymer films were completely fragmented and polymerized from ethylcyclohexane.

• Wind and Structures
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• 제4권1호
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• pp.31-44
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• 2001

Mean concentrations of ammonia gas released as a tracer from an isolated low-rise building have been measured and predicted. Predictions were calculated using computational fluid dynamics (CFD) and two dispersion models: a diffusion model and a Lagrangian particle tracking technique. Explicit account was taken of the natural variation of wind direction by a technique based on the weighted summation of individual steady state wind direction results according to the probability density function of the wind direction. The results indicated that at distances >3 building heights downstream the weighted predictions from either model are satisfactory but that in the near wake the diffusion model is less successful. Weighted solutions give significantly improved predictions over unweighted results. Lack of plume spread is identified as the main cause of inaccuracies in predictions and this is linked to inadequate resolution of flow features and mixing in the CFD model. Further work on non-steady state simulation of wake flows for dispersion studies is recommended.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.25.2-25.2
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• 2011

The tungsten oxide wire-like nanostructure is fabricated by deposition and thermal oxidation of tungsten metal on porous single wall carbon nanotubes (SWNTs). The morphology and crystalline quality of materials are investigated by SEM, TEM, XRD and Raman analysis. The results prove that $WO_3$ wire-like nanostructure fabricated on SWNTs show highly porous structures. Exposure of the sensors to NH3 gas in the temperature range of 150~300$^{\circ}C$ resulted in the highest sensitivity at $250^{\circ}C$ with quite rapid response and recovery time. Response time as a function of test concentrations and NH3 gas sensing mechanism is reported and discussed.

• Environmental Engineering Research
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• 제24권4호
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• pp.591-599
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• 2019

To convert sewage sludge to energy, drying-gasification characteristics during microwave heating were studied. During the gasification of carbon dioxide, the main products were gas, followed by char, and tar in terms of the amount. The main components of the producer gas were carbon monoxide and hydrogen including a small amount of methane and light hydrocarbons. They showed a sufficient heating value as a fuel. The generated tar is gravimetric tar, which is total tar. As light tars, benzene (light aromatic tar) was a major light tar. Naphthalene, anthracene, and pyrene (light polycyclic aromatic hydrocarbon tars) were also generated, but in relatively small amounts. Ammonia and hydrogen cyanide (precursor for NO_x) were generated from thermal decomposition of tar containing protein and nitrogen in sewage sludge. In the case of sludge char, its average pore diameter was small, but specific area, pore volume, and adsorption amounts were relatively large, resulting in superior adsorption characteristics.

• Bulletin of the Korean Chemical Society
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• 제23권8호
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• pp.1103-1105
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• 2002

H-ZSM-5 and γ-alumina were treated with formaldehyde and sodium carbonate. The treatment increased the amounts of weak acid sites, removing strong acid sites. The maximum temperature of weak acid sites in their ammonia TPD spectra shifted in the direction of high temperature. The modified H-ZSM-5 and g-alumina were mixed with the methanol synthesis catalyst to perform dimethyl ether synthesis from syn-gas. The modified catalysts showed better selectivity to dimethyl ether, minimizing the reforming reaction to carbon dioxide. The maximum yield of 53.3% to dimethyl ether was achieved under the reaction conditions of 54.4 atm, 523 K, and the feed rate of 4500 Lhr-1 .gcat-1.