• Title/Summary/Keyword: $NO_x$Concentration

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Lectin Activity and Chemical Characteristics of Escherichia coli, Lactobacillus spp. and Bifidobacterium spp. from Gastrointestinal Mucosa of Growing Pigs

  • Gao, W.;Meng, Q.X.
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.6
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    • pp.863-868
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    • 2004
  • Lectin activities and chemical characteristics of Escherichia coli, Lactobacillus spp. and Bifidobacterium spp. originating from the porcine cecal mucosal layer were studied based on hemagglutination assay (HA) and hemagglutination inhibition assay (HIA). Although all the bacterial strains were able to agglutinate erythrocytes of porcine or rabbit origin, much higher HA titers were consistently observed for Lactobacillus spp. than for E. coli or for Bifidobacterium spp. A remarkable reduction in HA titers occurred by the treatment of E. coli and Lactobacillus spp. with protease or trypsin and of Bifidobacterium spp. with protease, trypsin or periodate. There were no significant effects on the HA titers of the three groups of bacteria after the treatment with lipase. Hemagglutination of E. coli was strongly inhibited by D (+)-mannose and D (+)-galactose; Lactobacillus spp. by $\alpha$-L-rhamnose and methyl-$\beta$-galactopyranoside; Bifidobacterium spp. by D (+)-alactose, $\alpha$-L-rhamnose, $\alpha$-L-fucose, L (+)-arabinose, D (+)-mannose, D (-)-fructose at a relatively low concentration (1.43 to 3.75 mg/ml). These results, combined with the enhanced HA activities of the three bacterial strains by modification of rabbit erythrocytes with neuraminidase and abolished HA activity of E. coli after treatment with $\beta$-galactosidase, indicate that it might be the glycoproteinous substances surrounding the surface of the bacterial cells that are responsible for the adhesions of these microorganisms by recognizing the specific receptors on the red blood cell.

Effect of Premixed Fuel on the Combustion Characteristics of Premixed Charge Compression Ignition Engine (예혼합 연료에 따른 균일 예혼합 압축 착화 엔진의 연소특성)

  • Hwang, Jin-Woo;Kim, Dae-Sik;Rhyu, Youl;Lee, Ki-Hyung;Lee, Chang-Sik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.1
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    • pp.49-54
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    • 2003
  • The purpose of this work is to investigate the effect of premixed fuel on the reduction of exhaust emissions in premixed charge compression ignition engine. The premixed fuel is injected into the intake manifold to form homogeneous pre-mixture in the combustion chamber. The pre-mixture is ignited by a small amount of diesel fuel directly injected into the cylinder. In the case of gasoline as a premixed fuel of the engine, $NO_x$ and smoke concentration of exhaust emissions were reduced compared with the conventional diesel engine. But in the event of diesel fuel for premixed fuel, the rate of smoke reduction was small compared with the case of gasoline as a premixed fuel. HC and CO emissions were increased at high premixed ratio in the case of two premixed fuels. The combustion characteristics of the engine such as the combustion pressure, the rate of heat release, and other characteristics are compared.

Immobilized Small Sized Manganese Dioxide Sand in the Remediation of Arsenic Contaminated Water

  • Tiwari, Diwakar;Laldawngliana, C.;Lee, Seung-Mok
    • Environmental Engineering Research
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    • v.19 no.1
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    • pp.107-113
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    • 2014
  • Small sized manganese dioxide particles are immobilized onto the surface of sand by the wet impregnation process. The surface morphology of the solid, i.e., immobilized manganese dioxide natural sand (IMNS) is performed by taking scanning electron microscope images and characterized by the X-ray diffraction data. The specific surface area of the solid is obtained, which shows a significant increase in the specific surface area obtained by the immobilization of manganese dioxide. The $pH_{PZC}$ (point of zero charge) is found to be 6.28. Further, the IMNS is assessed in the removal of As(III) and As(V) pollutants from aqueous solutions under the batch and column operations. Batch reactor experiments are conducted for various physicochemical parametric studies, viz. the effect of sorptive pH (pH 2.0-10.0), concentration (1.0-25.0 mg/L), and background electrolyte concentrations (0.0001-0.1 mol/L $NaNO_3$). Further, column experiments are conducted to obtain the efficiency of IMNS under dynamic conditions. The breakthrough data obtained by the column experiments are employed in non-linear fitting to the Thomas equation, so as to estimate the loading capacity of the column for As(III) and As(V).

Development of Polymeric Water Absorbent Film(PWAF) for the Collection of Size-classified Fog Droplets

  • Ma, Chang-Jin;Mikilo-kasahara;Park, Kum-Chan
    • Journal of Korean Society for Atmospheric Environment
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    • v.17 no.E1
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    • pp.17-24
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    • 2001
  • For the purpose of collecting fog droplets as a function of size a new sampling method was developed in this study. Formation of 100$\pm$10㎛ thickness of polymeric water absorbent film (PWAF) on a nuclepore filter could be successfully realized. Also applicability of particle induced X-ray emission (PIXE) method to the chemical analysis of size-segregated fog droplets collected on PWAF was examined experimentally with synthetic fog droplets generated from a nebulizer. Absorption capacity of S-PAAS polymeric water absorbent shows marked decreases in the range less than 1 wt% and slight decrease between 1 and 3.5 wt% of every salt concentration. Dependency of absorption capacity on pH shows the maximum at pH 7. No apparent peak which can influence the quantitative analysis of elements dissolved and suspended in fog droplets was found at PIXE spectrum of PWAF blank. PWAF kept the original shape without rupture under the PIXE analytical conditions of beam intensity for 10 to 60 nA and irradiation time of 4∼5 min. It should be said that the proposed new technique in the work is helpful to get more detailed information of fog droplets, to clarify the fog formation processes, and to develop a model of acid deposition process.

Synthesis and Characterization of Y2O3:Eu Fine Particle

  • Park, Ji-Koon;Kang, Sang-Sik;Kwak, Min-Gi;Choi, Seung-Suk;Kim, Jae-Hyung;Nam, Sang-Hee
    • Transactions on Electrical and Electronic Materials
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    • v.6 no.4
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    • pp.169-172
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    • 2005
  • [ $Y_2O_3:Eu$ ] powder was synthesized using a solution-combustion method by dissolving $(CH_3CO_2)_3Y$ and $(CH_3CO_2)_3$ Eu in methyl-alcohol solution. Results from X-ray diffractometery (XRD), thermogravimetry (TG)-differential thermal analysis (DTA) show that $Y_2O_3:Eu$ crystallizes completely when the dry powder is sintered at $500^{\circ}C$. The investigated optical properties were the photoluminescence emission spectra, the excitation spectra and luminescence decay curve. Europium (Eu) concentration had no observable effect on the optical spectrum which depended on the emission intensity. The mean lifetime of synthesized phosphors was $2.3\~2.6 ms$.

Stabilization Characteristics of DME-Air Diffusion Flames Depending on the Configuration of the Fuel-Air Tubes in Half Closed Combustion Spaces (반밀폐 연소공간 내 동축관 형상에 따른 DME-공기 확산화염의 안정화 특성)

  • Kim, Go-Tae;Kim, Nam-Il
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.11
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    • pp.916-923
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    • 2009
  • The effects of configuration of fuel and air tubes on the flame stabilization were experimentally investigated in half-closed combustors. Flame behaviors and stabilities of methane, propane, and DME flames were compared by changing tube diameters and the locations of the fuel and air tubes. It was found that flammability limits are significantly affected by the outlet boundary condition, which disturbs compositions of burned and unburned mixtures near the flame base. And it was found that there exist critical inner tube heights, over which flame stability is determined only by the fuel flow rate. Conclusively, flame stabilization is governed by the flame propagation velocity in an ordinary mixing flow and the non-uniform mixture concentration in the combustion space which is affected by flow recirculation and the combustor configuration. The compositions of $NO_x$ and CO were compared to know basic characteristics of methane, propane, and DME flames.

Biochemical and Trace Mineral Analysis of Silajit Samples From Pakistan

  • Shafiq Muhammad Imtiaz;Nagra Saeed Ahmad;Batool Nayab
    • Nutritional Sciences
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    • v.9 no.3
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    • pp.190-194
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    • 2006
  • Silajit is a blackish brown pitch-like gummy substance. It is an important Unani and Ayurvedic medicine widely used in the treatment of many diseases and as nutritional supplement It is found in certain mountainous regions of Pakistan, Afghanistan, India, Nepal, Australia and Russia. Silajit samples of Pakistani origin were obtained from different sources and analyzed for their physical characteristics and biochemical & elemental composition. X-ray diffraction studies on Silajit showed that it is an amorphous substance and has no crystalline structure. Also, pH studies of Silajit (2 g/L of water) indicated that it was slightly acidic in nature and ranged from 3.45 to 7.23. Conductivity ranged from 157.7 to 330. Amino acid analysis revealed that Silajit contained lysine and alanine in higher amounts than all other amino acids and ranged from 1456 to 2240 and 68 to $1615{\eta}mole/g$, respectively. Mean concentration of arsenic, mercury, cadmium, lead, copper and zinc was 73.15, 104.92, 0.496, 3.89, 4.04 and 17.23 ppm, respectively. Silajit samples were also analyzed for calcium, potassium and sodium.

Biomechanical Properties and Cytotoxicity of Chitosan Patch Scaffold for Artificial Eardrum (인조고막용 키토산 패치 지지체의 생체역학적 특성 및 독성 평가)

  • Chung, Jong-Hoon;Kim, Jang-Ho;Choung, Yun-Hoon;Im, Ae-Lee;Lim, Ki-Taek;Hong, Ji-Hyang;Choung, Pill-Hoon
    • Journal of Biosystems Engineering
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    • v.32 no.1 s.120
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    • pp.57-62
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    • 2007
  • The objectives of this study were to prepare a new artificial eardrum patch using water-insoluble chitosan for healing the tympanic membrane perforations and to investigate biomechanical properties and cyotoxicity of the chitosan patch scaffold (CPS). Tensile strength and elongation at the rupture point of CPSs were 2.49-74.05 MPa and 0.11-107.06%, respectively. As the biomechanical properties or CPSs varied with the concentration of chitosan and glycerol, the proper conditions for the CPS were found out. SEM analysis showed very smooth and uniform surface of CPSs without pores at x1000. The result of MTT test showed that CPSs had no cytotoxicity.

Sensibility Study for PBL Scheme of WRF-CMAQ (PBL Scheme에 대한 WRF-CMAQ 민감도 분석)

  • Moon, Nan-Kyoung;Kim, Soon-Tae;Seo, Ji-Hyun
    • Journal of Korean Society for Atmospheric Environment
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    • v.27 no.6
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    • pp.791-804
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    • 2011
  • Numerical simulations were carried out to investigate the impact of PBL (Planetary boundary layer) scheme implemented in WRF on the result of meteorological fields and CMAQ modeling. 25-day period, representing high ozone concentration, was selected for the simulations. The three WRF domains covered East Asia region, Korean Peninsula and Seoul metropolitan area. The sensitivity of WRF-CMAQ modeling to the various PBL schemes was assessed and quantified by comparing model output and against observation from the meteorological and the air quality monitoring network within the domain. The meteorological variables evaluated included temperature, wind speed and direction over surface sites and upper air sounding sites. The CMAQ variables included gaseous species $O_3$ and $NO_x$ over monitoring stations. Although difference of PBL schemes implemented in WRF, they did not appreciably affect the WRF and CMAQ performance. There are partially differences between non-local and local mixing scheme, but are not distinct differences for the results of weather and air quality. It is suggested that impact of parameterization of vertical eddy diffusivity scheme in CMAQ also need to be researched in the future study.

Bronchial Hyperresponsiveness in Workers Exposed to Isocyanates (Isocyanates 폭로 근로자들의 기관지 과민성)

  • Choi, Kyeong-Sook;Kim, Kyoo-Sang;Choi, Byung-Soon;Choi, Jung-Keun;Lee, Se-Hui;Moon, Young-Hahn
    • Journal of Preventive Medicine and Public Health
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    • v.29 no.1 s.52
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    • pp.103-112
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    • 1996
  • We studied the association of nonspecific bronchial hyperresponsiveness with general characteristics, exposure concentration, respiratory symptoms, chest x-ray findings, past histories and pulmonary function. We determined bronchial hyperresponsiveness by methacholine challenge test. And we conducted a respiratory symptom questionnaire and performed spirometry on 111 workers occupationally exposed to isocyanates in various industries. About 21.6% of subjects had bronchial hyperresponsiveness. No significant differences were observed between the hyperresponsive and non-responsive group with respect to age, sex, employment period, height, and smoking histories. Cough and breathlessness were significantly associated with the bronchial hyperresponsiveness. The hyperresponsive group had more experience of bronchitis and asthma in the past than the non-responsive group. The lower $FEV_1\;and\;FEV_1%$ were closely related with bronchial hyperresponsiveness. Bronchial hyperresponsiveness seems to be associated with some of respiratory symptoms, past histories and pulmonary function parameters in workers exposed to isocyanates.

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