• Title/Summary/Keyword: Nitrogen injection

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A Basic Study on Combustion Characteristics of Radical Ignition Sub-chamber Type CNG DI Engine (라디칼 점화 부실 혼합형 CNG DI 엔진의 연소특성에 관한 기초연구)

  • Chung, Sung-Sik;Hwang, Seong-Ill;Lim, Choon-Mee
    • Journal of Power System Engineering
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    • v.22 no.1
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    • pp.56-63
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    • 2018
  • After the recent fabrication of diesel vehicle exhaust gas by Volkswagen, nitrogen oxides ($NO_x$) and particulate matter (PM) are drawing attention as representative pollutants included in exhaust gas. When gasoline and diesel fuels are combusted through direct injection into a combustion chamber at high pressure, PM emission is actually increased. To find a solution to this problem, a basic study was conducted to derive an optimized variable for combustion of compressed natural gas (CNG) by applying CNG, acknowledged as a clean fuel, to direct injection system. The essence of this study is in the introduction of a radical ignition technology for compressed natural gas (RI-CNG) in a sub-chamber type engine. The direct injection system was applied to a sub-chamber to remove residual gas from previous combustion cycle. In addition, optimal mixer distribution was achieved by precisely setting ignition timing based on fuel injection timing and excess air ratio.

Effect of NH3 Uniformity Index on SCR System According to Urea Spray Characteristics (요소수 분무특성이 SCR시스템 내 분무균일도에 미치는 영향)

  • Kim, Se Hun;Ko, Jin Seok;Ko, Jae Yu;Cho, Young Jun;Lee, Dong Ryu
    • Journal of ILASS-Korea
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    • v.24 no.4
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    • pp.178-184
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    • 2019
  • Diesel engines have the advantages of higher thermal efficiency and lower CO2 emissions than gasoline engines, but have the disadvantages that particulate matter (PM) and nitrogen oxides (NOx) emissions are greater than those of gasoline engines. In particular, nitrogen oxides (NOx) emitted from diesel engines generates secondary ultrafine dust (PM2.5) through photochemical reactions in the atmosphere, which is fatal to humans. In order to reduce nitrogen oxides (NOx), pre-treatment systems such as EGR, post-treatment systems such as LNT and Urea SCR have been actively studied. The Urea SCR consists of an injection device injecting urea agent and a catalytic device for reducing nitrogen oxides (NOx). The nitrogen oxide (NOx) reduction performance varies greatly depending on the urea uniformity in the exhaust pipe. In this study, spray characteristics according to the spray hole structure were confirmed, and the influence of spray uniformity on spray characteristics was studied through engine evaluation.

EXPERIMENTAL STUDY ON THE EFFECTS OF THE ANTICANCER AGENT(ENDOXAN) TO THE RAT'S TEETH (항암제가 치아조직에 미치는 영향에 관한 실험적 연구)

  • Yang, Dong-Kyu
    • The Journal of the Korean dental association
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    • v.15 no.9
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    • pp.749-753
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    • 1977
  • The author studied the effects of anticancer Endoxan to the rat's teeth. Two hundred pregnant rats were used. The experimental rats were given an intramuscular injection of Endoxan as nitrogen mustard derivatives 10mg. per 40gm of body weight. In order to investigate effects of Endoxan to the teeth of rats the control and experimental rats group wee sacrificed on 1,3,5,7 and 14days, and made preparation for histopathologic findings. The rusults were as follows: 1. In several days (about 5days) after injection of Endoxan, tooth germs of cap stage, bell stage, and dental lamina were irregular arranged form as compared with in the control group teeth. 2. Irregular arranged cell were recovered from 14days after injection of Endoxan.

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Performance and emission characteristics of biodiesel blends in a premixed compression ignition engine with exhaust gas recirculation

  • Kathirvelu, Bhaskar;Subramanian, Sendilvelan
    • Environmental Engineering Research
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    • v.22 no.3
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    • pp.294-301
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    • 2017
  • This paper is based on experiments conducted on a stationary, four stroke, naturally aspirated air cooled, single cylinder compression ignition engine coupled with an electrical swinging field dynamometer. Instead of 100% diesel, 20% Jatropha oil methyl ester with 80% diesel blend was injected directly in engine beside 25% pre-mixed charge of diesel in mixing chamber and with 20% exhaust gas recirculation. The performance and emission characteristics are compared with conventional 100% diesel injection in main chamber. The blend with diesel premixed charge with and without exhaust gas recirculation yields in reduction of oxides of nitrogen and particulate matter. Adverse effects are reduction of brake thermal efficiency, increase of unburnt hydrocarbons (UBHC), carbon monoxide (CO) and specific energy consumption. UBHC and CO emissions are higher with Diesel Premixed Combustion Ignition (DPMCI) mode compared to compression ignition direct injection (CIDI) mode. Percentage increases in UBHC and CO emissions are 27% and 23.86%, respectively compared to CIDI mode. Oxides of nitrogen ($NO_x$) and soot emissions are lower and the percentage decrease with DPMCI mode are 32% and 33.73%, respectively compared to CIDI mode.

Effect of Fuel Injection Timing on Nitrous Oxide Emission from Diesel Engine (디젤엔진에서 연료 분사시기가 아산화질소에 미치는 영향)

  • Yoo, Dong-Hoon
    • Journal of Power System Engineering
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    • v.18 no.6
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    • pp.106-112
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    • 2014
  • The diesel engine, which has high compression ratio than other heat engines, has been using as the main power source of marine transport. Especially, since marine diesel engines offer better specific fuel consumption (SFC), it is environment-friendly compared to those used in other industries. However, attentio should be focused on emissions such as nitrous oxide ($N_2O$) which is generated from combustion of low-grade fuels. Because $N_2O$ in the atmosphere is very stable, the global warming potential (GWP) of $N_2O$ is 310 times as large as that of $CO_2$, and it becomes a source of secondary contamination after photo-degradation in the stratosphere. It has been hitherto noted on the $N_2O$ exhaust characteristics from stationary power plants and land transportations, but reports on $N_2O$ emission from the marine diesel engine are very limited. In this experimental study, a author investigated $N_2O$ emission characteristics by using changed diesel fuel components of nitrogen and sulfur concentration, assessed on the factors which affect $N_2O$ generation in combustion. The experimental results showed that $N_2O$ emission exhibited increasement with increasing of sulfur concentration in fuel. However, all kinds of nitrogen component additives used in experiment could not change $N_2O$ emission.

Effects of Additional Bubbling on RH Vacuum Degassing Process with Water Model Experiment (수모델을 사용한 RH 진공 탈가스장치에서의 추가 버블링 효과)

  • Jang, Young-Hwan;Kim, Young-Tae;Yi, Kyung-Woo
    • Korean Journal of Metals and Materials
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    • v.48 no.5
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    • pp.424-429
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    • 2010
  • In the RH process, it is possible to obtain quicker processing times by enhancing the decarburization rates at a low carbon range of steel melt through Ar gas injection into the vacuum vessel. The RH decarburization reaction was simulated through a dissolved oxygen removal reaction by injecting nitrogen into a 1/8 scale RH water model system. The gas nozzles for the N$_{2}$ injection into the vacuum vessel were located at the lowest level of the vessel's outer wall. The nitrogen bubbling in the vacuum vessel resulted in an increase in the reaction rate constant, which rose in accordance with an increase in the bubbling flow rate and number of nozzles used. However, there was almost no variation in the reaction rate constant, which depended on the horizontal positions of the bubbling nozzles.

Study on Effects of Pressure Ratio on the Wall-impingement Spray Characteristics of Nitrogen Gas using CNG Injector

  • Pham, Quangkhai;Chang, Mengzhao;Choi, Byungchul;Park, Suhan
    • Journal of ILASS-Korea
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    • v.27 no.1
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    • pp.1-10
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    • 2022
  • In this study, an experimental investigation on the effects of the pressure ratio on the wall-impingement spray characteristics of nitrogen gas using a compressed natural gas (CNG) injector was conducted. The transient development of the impingement spray was recorded by a high speed camera with Z-type Schlieren visualization method. The spray behavior under various pressure ratio conditions were analyzed. The experimental results showed that the pressure ratio has positive effect on the development of spray wall-impingement. The effects of the above factor were evaluated in a constant volume chamber at atmospheric conditions. The data from test showed that, with the increase of the pressure ratio, the spray tip penetration (STP) quickly increases before the impingement and gradually increases after the impingement. Additionally, the spray velocity first increases and then sharply decreases on regardless of the injection pressure level. As the spray spreading angle increases, spray area and volume increases rapidly with the increase in STP at the beginning of injection, and finally entered a stable range, has a great correlation with the increase of pressure ratios.

Effects of Chromium Supplementation and Lipopolysaccharide Injection on Physiological Responses of Weanling Pigs

  • Lee, D.N.;Weng, C.F.;Yen, H.T.;Shen, T.F.;Chen, B.J.
    • Asian-Australasian Journal of Animal Sciences
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    • v.13 no.4
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    • pp.528-534
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    • 2000
  • Sixteen specific pathogen free 4-wk-old crossbred weanling pigs were allotted into a $2{\times}2$ factorial design to evaluate chromium picolinate (CrPic) on growth and physiological responses. Two factors included (1) no Cr or 400 ppb Cr supplementation from chromium picolinate and (2) lipopolysaccharide (LPS) injection on day 21 (d 21) and 35 (d 35) compared to saline application. Plasma samples and rectal temperature were obtained from all piglets before (h 0) and at 2 h (h 2), 4 h (h 4), 8 h (h 8), and 24 h (h 24) after LPS injection ($200{\mu}g/kg$ BW, intraperitoneally). The rectal temperature on d 21 was significantly decreased (p<0.05) of about $0.36^{\circ}C$ with Cr supplementation before LPS injection. After LPS injection, the daily gain of piglets was decreased during d 35-38. Supplementation of Cr had no effect in general on growth performance particularly after LPS injection. The plasma glucose, triglycerides and urea nitrogen concentrations were changed in different ways after LPS injection. Plasma cortisol level was significantly elevated at h 2 after LPS injection on d 21 and d 35. The supplementation of Cr in the diet can delayed plasma cortisol release on d 35. The results suggest that 400 ppb Cr supplementation from CrPic may modulate the physiological response during immune stress in weanling pigs.

A Study on the Biological Treatment of RO Concentrate Using Aerobic Granular Sludge (호기성 그래뉼 슬러지를 이용한 RO 농축수의 생물학적 처리에 관한 연구)

  • Kim, Hyun Gu;Ahn, Dae Hee;Cho, Eun Ha;Kim, Han Yong;Ye, Hyoung Young;Mun, Jung Soo
    • Journal of Korean Society of Environmental Engineers
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    • v.38 no.2
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    • pp.79-86
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    • 2016
  • The purpose of this study is to efficiently improve biological sequencing batch reactor (SBR) system of high-concentrated nitrate nitrogen in reverse osmosis (RO) concentrates by total dissolved solids (TDS) regulation. Since a laboratory-scale SBR system had been operated, we had analyzed specific denitrification rate (SDNR) and specific oxygen uptake rate (SOUR) for microbial activity in according to various injection concentration of TDS. As a result, higher injection concentration of TDS decreased SDNR, and delayed denitrification within denitrification process. Moreover, the higher injection concentration of TDS was, the lower microbial activity was during operation of laboratory-scale SBR system. Therefore, the regulation of TDS injection concentration is necessary to improve efficiency of nitrate nitrogen in the biological SBR system, and treatment of calcium ion ($Ca^{2+}$) is also specifically focused to remove nitrate nitrogen. Moreover, analytical data of SDNR and SOUR can be the effective kinetic design parameters to application of biological treatment of RO concentrate by aerobic granular sludge (AGS).

Porcine Somatotropin Improves the Efficiency of Digestible Protein Use for Protein Deposition by Growing Pigs

  • Lee, K.U.;Boyd, R.D.;Austic, R.E.;Ross, D.A.;Beermann, D.H.;Han, In K.
    • Asian-Australasian Journal of Animal Sciences
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    • v.12 no.7
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    • pp.1096-1103
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    • 1999
  • A study was conducted to clarify the impact of recombinant porcine somatotropin (pST) on the efficiency of absorbed nitrogen use for protein deposition in growing pigs. Three levels of dietary crude protein (9.0, 11.5, 14.0% CP) were used. Each had either a sub-optimum or near optimum lysine: CP concentration (Low-lysine, 3.8 g/100 g CP and High-lysine, 5.5 g/100g CP) in order to achieve different metabolic efficiencies for nitrogen deposition (ca. 45 vs. 60%). Twelve crossbred female pigs $(59{\pm}4kg\;BW)$ were placed in metabolism cages and fitted with bladder catheters. Each pig received an excipient injection daily for the first 10-d, a pST (5 mg/d) injection for the second 10-d, and then excipient for the last 10-d. Pigs were randomly assigned to one of six dietary treatments (2 pigs/diet) and fed 4 times per d at $92g/kg\;BW^{0.75}$ $(3{\times}maintenance)$. Means for the excipient period were compared to means for the pST period. Urinary nitrogen (N) output declined in pST-treated pigs (p<0.01) irrespective of dietary protein content or lysine level. Nitrogen retention increased by an average of 11% (p<0.01) with pST treatment (726 vs. $803mg\;N/kg^{0.75}\;BW/d$). Forty-eight percent of the absorbed N was retained with Low-lysine diets, but this increased to 53% with pST injection (+11%, p<0.01). Pigs fed High-lysine diets retained 62% of absorbed N which increased to 69% with pST (+11% p<0.01). the addition of lysine improved N use by 27% (High vs. Low, p<0.01), but the effect of lysine and pST was additive (+40%). Therefore, pST improves N retention and the efficiency of apparently absorbed N use in growing pigs (>60kg). It does so with diets having the potential for either low or high efficiencies of N use (48% and 62%). More work is needed to determine if the partial efficiency of N use improves in direct proportion to pST dose since the improvement in protein deposition is a function of pST dose.