• Title/Summary/Keyword: Air Chemistry

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Effects of solanum macrocarpon (African eggplant) on haematological parameters of wistar rats exposed to urban air pollution

  • Olajire, A.A.;Azeez, L.
    • Advances in environmental research
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    • v.1 no.2
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    • pp.109-123
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    • 2012
  • Our study investigated the effects of Solanum macrocarpon (African eggplant) on haematological and biochemical parameters of male albino rats exposed to urban air pollution ($O_3$, $PM_{10}$, CO, $SO_2$, $NO_2$ and VOC). Male albino Wistar rats were exposed for 63 days either to urban air pollution without treatment (A); oral supplementation with Solanum macrocarpon given at 36 and 75 mg/kg body weight (BW), representing C and D respectively and exposed to air pollution; oral supplementation with Solanum macrocarpon given at 75 mg/kg BW after exposure to air pollution (B); or kept in animal house without exposure to air pollution (E). Animals exposed to air pollution showed significant alterations in haematological and biochemical parameters signaling that the blood and organs were badly injured. There were significant elevations in white blood cells (WBC) and its indices, reduction in red blood cells (RBC) and significant depletions of non-enzymic antioxidants, total protein and increase in lipid peroxidation values. Solanum macrocarpon supplementation in the feed of animals halted significantly the deleterious effects of air pollution, with co-administration during exposure given better results.

A Study on Air Emission Spectra Observed by Using Electrothermal-Hollow Cathode Glow Discharge Spectrometry (Et-HCGDS) (Electrothermal-Hollow Cathode Glow Discharge Spectrometry(Et-HCGDS)를 이용하여 살펴본 Air Emission에 관한 연구)

  • Lee, Sang Chun;Shin, Jung-Sook;Kang, Mi-Ra
    • Journal of the Korean Chemical Society
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    • v.39 no.5
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    • pp.399-407
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    • 1995
  • Electrothermal-Hollow Cathode Glow Discharge Spectrometry (Et-HCGDS) has been constructed in our laboratory for in-situ monitoring of traceble amounts of rare earth elements and actinides. Et-HCGDS is the portable glow discharge system that can perform the trace analysis of elements. The main structural design of Et-HCGDS was based upon the electrothermal heating and glow discharge techniques. More details on Et-HCGDS are available elsewhere. In this study, air was used as a flow gas for the glow discharge system. As a result, the emission spectra of air were collected and the assignment of air emission lines was performed with helps of pure nitrogen and oxygen emission spectra and previously published results. We found that the emission lines of air plasma were mainly due to nitrogen molecules. This paper includes the complete assignments of the air emission lines observed by using Et-HCGDS. Also, this study will be an useful reference for spectrochemical anaysis including air analysis.

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Electrochemical Properties for the Corrosion of Zinc Anode with Different Particle Size and Shape in Zinc/air Batteries (입자의 크기가 다른 아연공기전지용 아연음극의 부식에 관한 전기화학적 특성 연구)

  • Yang, Won-Geun;Hong, Jung-Eui;Oh, Rye-Gyeong;Oh, Ji-Woo;Kong, Young-Min;Ryu, Kwang-Sun
    • Journal of Powder Materials
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    • v.20 no.3
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    • pp.186-190
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    • 2013
  • The electrochemical performance for the corrosion of zinc anodes according to particle size and shape as anode in Zn/air batteries was study. We prepared five samples of Zn powder with different particle size and morphology. For analysis the particle size of theme, we measured particle size analysis (PSA). As the result, sample (e) had smaller particle size with $10.334{\mu}m$ than others. For measuring the electrochemical performance of them, we measured the cyclic voltammetry and linear polarization in three electrode system (half-cell). For measuring the morphology change of them before and after cyclic voltammetry, we measured Field Emission Scanning Electron Microscope (FE-SEM). From the cyclic voltammetry, as the zinc powder had small size, we knew that it had large diffusion coefficient. From the linear polarization, as the zinc powder had small size, it was a good state with high polarization resistance as anode in Zn/air batteries. From the SEM images, the particle size had increased due to the dendrite formation after cyclic voltammetry. Therefore, the sample (e) with small size would have the best electrochemical performance between these samples.

Numerical study on extinction and acoustic response of diluted hydrogen-air diffusion flames with detailed and reduced chemistry (상세 및 축소 반응 메커니즘을 이용한 희석된 수소-공기 확산화염의 소염과 음향파 응답 특성에 관한 수치해석)

  • Son, Chae-Hun;Jeong, Seok-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.11
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    • pp.1527-1537
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    • 1997
  • Extinction characteristics and acoustic response of hydrogen-air diffusion flames at various pressures are numerically studied by employing counterflow diffusion flame as a model flamelet in turbulent flames in combustion chambers. The numerical results show that extinction strain rate increases linearly with pressure and then decreases, and increases again at high pressures. Thus, flames are classified into three pressure regimes. Such nonmonotonic behavior is caused by the change in chemical kinetic behavior as pressure rises. The investigation of acoustic-pressure response in each regime, for better understanding of combustion instability, shows different characteristics depending on pressure. At low pressures, pressure-rise causes the increase in flame temperature and chain branching/recombination reaction rates, resulting in increased heat release. Therefore, amplification in pressure oscillation is predicted. Similar phenomena are predicted at high pressures. At moderate pressures, weak amplification is predicted since flame temperature and chain branching reaction rate decreases as pressure rises. This acoustic response can be predicted properly only with detailed chemistry or proper reduced chemistry.

Lifetime Prediction and Aging Behaviors of Nitrile Butadiene Rubber under Operating Environment of Transformer

  • Qian, Yi-hua;Xiao, Hong-zhao;Nie, Ming-hao;Zhao, Yao-hong;Luo, Yun-bai;Gong, Shu-ling
    • Journal of Electrical Engineering and Technology
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    • v.13 no.2
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    • pp.918-927
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    • 2018
  • Based on the actual operating environment of transformer, the aging tests of nitrile butadiene rubber (NBR) were conducted systematically under four conditions: in air, in transform oil, under compression in air and under compression in transform oil to studythe effect of high temperature, transform oil and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber and predict the lifetime. The effects of liquid media and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber were studied by using characterization methods such as IR spectrosc-opy, thermogravimetric measurements, Differential Scanning Calorimetry (DSC) measurements and mechanical property measurements. The changes in physical properties during the aging process were analyzed and compared. Different aging conditions yielded materials with different properties. Aging at $70^{\circ}C$ under compression stress in oil, the change in elongation at break was lower than that aging in oil, but larger than that aging under compression in air. The compression set or elongation at break as evaluation indexes, 50% as critical value, the lifetime of NBR at $25^{\circ}C$ was predicted and compared. When aging under compression in oil, the prediction lifetime was lower than in air and under compression in air, and in oil. It was clear that when predicting the service lifetime of NBR in oil sealing application, compression and media liquid should be involved simultaneously. Under compression in oil, compression set as the evaluation index, the prediction lifetime of NBR was shorter than that of elongation at break as the evaluation index. For the life prediction of NBR, we should take into account of the performance trends of NBR under actual operating conditions to select the appropriate evaluation index.

Determining Potassium Bromate in the Inhalable Aerosol Fraction in Workplace Air with Ion Chromatography

  • Kowalska, Joanna;Lis, Monika;Biesaga, Magdalena
    • Safety and Health at Work
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    • v.12 no.2
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    • pp.209-216
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    • 2021
  • Background: The article presents the results of studies performed in order to develop a new method of airborne potassium bromate(V) determination at workplaces. Methods: The method is based on a collection of the inhalable fraction of potassium bromate(V) using the IOM Sampler, then extraction of bromates with deionized water and chromatographic analysis of the obtained solution. The analysis was performed using ion chromatography with conductometric detection. The tests were performed on a Dionex IonPac®AS22 analytic column (250 × 4 mm, 6 ㎛) with AG22 precolumn (50 × 4 mm 11 ㎛). Results: The method provides for potassium bromate(V) determination within the concentration range of 0.043 ÷ 0.88 mg/m3 for an air sample of 0.72 m3 in volume, i.e., 0.1-2 times the exposure limit value as proposed in Poland. The method was validated in accordance with PN-EN 482. The obtained validation data are as follows: measuring range: 3.1-63.4 ㎍/mL, limit of detection (LOD) = 0.018 ㎍/mL and limit of quantification (LOQ) = 0.053 ㎍/mL. The developed method has been tested in the work environment, on laboratory employees having contact with potassium bromate(V). Conclusion: The analytical method allowed the determination of the inhalable fraction of airborne potassium bromate(V) at workplaces and can be used to assess occupational exposure.

Self-assembly of Dumbbell-shaped Rod Amphiphiles Based on Dodeca-p-phenylene

  • Huang, Zhegang;Liu, Libin;Lee, Eun-Ji;Lee, Myong-Soo
    • Bulletin of the Korean Chemical Society
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    • v.29 no.8
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    • pp.1485-1490
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    • 2008
  • Dumbbell-shaped aromatic amphiphilic molecules consisting of a dodeca-p-phenylene as a rigid segment and oligoether dendrons as a flexible chains were synthesized, characterized, and their aggregation behavior was investigated in the bulk and at the air-water interface. In contrast to the molecule 2 which shows a nematic liquid crystalline state, molecule 1 based on shorter dendritic chains was observed to self-assemble into a 3-D primitive orthorhombic supercrystal. And molecule 1 at the air-water interface was observed to reorganize from circular plates to ring structures by lateral compressions.

Effects of Aging on Electrocatalytic Activities of Pt and Pd Nanoparticles

  • Dutta, Gorachand;Yang, Haesik
    • Journal of Electrochemical Science and Technology
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    • v.7 no.1
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    • pp.27-32
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    • 2016
  • Although the time dependences of the electrocatalytic activities of Pt and Pd nanoparticles during electrochemical operations have been widely studied, the time dependences under nonpolarized conditions have never been investigated in depth. This study reports the changes in the electrocatalytic activities of Pt and Pd nanoparticles with aging in air and in solution. Pt (or Pd) nanoparticle-modified electrodes are obtained by adsorbing citrate-stabilized Pt (or Pd) nanoparticles on amine-modified indium-tin oxide (ITO) electrodes, or by electrodeposition of Pt (or Pd) nanoparticles on ITO electrodes. The electrocatalytic activities of freshly prepared Pt and Pd nanoparticles in the oxygen reduction reaction slowly decrease with aging. The electrocatalytic activities decrease more slowly in solution than in air. An increase in surface contamination may cause electrocatalytic deactivation during aging. The electrocatalytic activities of long-aged Pt (or Pd) nanoparticles are significantly enhanced and recovered by NaBH4 treatment.