• Title/Summary/Keyword: Metallic particle

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Descriptive Profile and Liking/Disliking Factors for Aseptic-packaged Rice Porridge (무균포장죽의 묘사적 특성과 소비자 기호 유발 인자 결정)

  • Kwak, Han Sub;Oh, Ye-Jin;Kang, Han-Bit;Kim, Tae Hyoung
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.42 no.11
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    • pp.1878-1885
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    • 2013
  • The purposes of this study are to generate sensory profile, measure consumer acceptance, and determine liking and disliking factors of aseptic-packaged rice porridges (APRP). Five APRPs made by five different rice cultivars were used for this study. Twenty-one attributes were generated by trained panelists. Finally, 16 attributes were determined as descriptive terms for APRP. Each cultivar showed a different descriptive sensory profile. In a consumer acceptance test, there was no statistical difference (P>0.05) in the acceptances of the overall, appearance, taste, texture, viscosity, and rice particle texture among the 5 APRPs. SW52 showed the highest acceptance ratings in the overall, appearance, taste and texture, followed by SR. A total of 52% of consumers showed preference toward SW52 and SR. SW63 showed the lowest ratings and no consumer preference pattern. Consumers were divided into two groups by a cluster analysis; one was the consumers (C1) who liked APRP, and the other was the consumers (C2) who had a neutral stand in general. By correlating the results from descriptive analysis and consumer ratings from C1, liking and disliking factors for consumer acceptance were determined. The disliking factors were bitterness, feeling of surface, stickiness, metallic flavor, roasted aroma, and thickness. The liking factors were old cooked rice aroma/flavor. The disliking factors dominated in the determination of acceptability of APRP. Selecting rice cultivars that had low intensities of disliking factors is the key for APRP development.

Comparison of Metal Contents in Respirable Particulate Mass by Particle Size and Season in Seoul and Asan City (서울.아산지역 호흡성먼지의 금속함량에 관한 연구)

  • Choi, Yun-Na;Jeon, Yong-Taek;Jang, Bong-Ki;Yang, Won-Ho;Yom, Yoon-Ki;Son, Bu-Soon
    • Journal of environmental and Sanitary engineering
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    • v.23 no.1
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    • pp.33-48
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    • 2008
  • The purpose of this study was to characterize background mass concentration of $PM_{10},\;PM_{2.5}$ and metallic composition from June 2004 to June 2005 in comparison with Seoul and Asan city. The results were as follows: 1. Annual mean of $PM_{10}$ concentrations in Seoul and Asan were $56.95({\pm}25.63){\mu}g/m^3,\;57.02({\pm}27.22){\mu}g/m^3$ respectly. 2. Annual mean of $PM_{2.5}$ concentrations in Seoul and Asan were $46.97({\pm}40.36){\mu}g/m^3,\;42.16({\pm}21.79){\mu}g/m^3$ respectly. 3. The average $PM_{2.5}/PM_{10}$ ratio was 0.82 in Seoul and 0.74 in Asan city. 4. The concentration of $PM_{10},\;PM_{2.5}$ were the highest in spring and the lowest in summer. Asan was higher than Seoul in spring and summer. 5. The results showed that average $PM_{10}$ composition order as Si>Fe>Pb>Zn>Mn in Seoul and Si>Fe>Zn>Pb>Mn in Asan. The concentration of metals in $PM_{10}$ of Seoul that Cr, Cu, Fe, Mn were high in spring and Zn was low in Fall. Fe, Mn were high in spring of Asan. 6. The results showed that average $PM_{2.5}$ composition order as Si>Pb>Fe>Zn>Mn in Seoul and Si>Fe>Pb>Zn>Cr in Asan. The concentration of metals in $PM_{2.5}$ of Seoul that Cr was high in spring. 7. The result showed that relation between Cr and Cu, Cu and Fe, Fe and Mn, Mn and Zn, Zn and Si in Seoul, Cr and Zn, Cu and Pb, Zn and Pb, Pb and Mn in Asan. The result showed that $PM_{10}$ concentration exceeding $50{\mu}g/m^3$(US-EPA Standard) and $PM_{2.5}$ concentration exceeding $15{\mu}g/m^3$(US-EPA Standard). In urban area, the monitoring of $PM_{2.5}$ permits the anthropogenic sources and the interference of natural sources with respect to $PM_{10}$ measurements.

Photodecomposition of Concentrated Ammonia over Nanometer-sized TiO2, V-TiO2, and Pt/V-TiO2 Photocatalysts

  • Choi, Hyung-Joo;Kim, Jun-Sik;Kang, Mi-Sook
    • Bulletin of the Korean Chemical Society
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    • v.28 no.4
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    • pp.581-588
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    • 2007
  • To enhance the photodecomposition of concentrated ammonia into N2, Pt/V-TiO2 photocatalysts were prepared using solvothermal and impregnation methods. Nanometer-sized particles of 0.1, 0.5 and 1.0 mol% V-TiO2 were prepared solvothermally, and then impregnated with 1.0 wt% Pt. The X-ray diffraction (XRD) peaks assigned to V2O5 at 30.20 (010) and Pt metal at 39.80 (111) and 46.20 (200) were seen in the 1.0 wt% Pt/ 10.0 mol% V-TiO2. The particle size increased in the order: pure TiO2, V-TiO2 and Pt/V-TiO2 after thermal treatment at 500 °C, while their surface areas were in the reverse order. On X-ray photoelectron spectroscopy (XPS), the bands assigned to the Ti2p3/2 and Ti2p1/2 of Ti4+-O were seen in all the photocatalysts, and the binding energies increased in the order: TiO2 < Pt/V-TiO2 < V-TiO2. The XPS bands assigned to the V2p3/2 (517.85, 519.35, and 520.55 eV) and V2p1/2 (524.90 eV) in the V3+, V4+ and V5+ oxides appeared over V-TiO2, respectively, while the band shifted to a lower binding energy with Pt impregnation. The Pt components of Pt/ V-TiO2 were identified at 71.60, 73.80, 75.00 and 76.90 eV, which were assigned to metallic Pt 4f7/2, PtO 4f7/2, PtO2 4f7/2, and PtO 4f5/2, respectively. The UV-visible absorption band shifted closer towards the visible region of the spectrum in V-TiO2 than in pure TiO2 and; surprisingly, the Pt/V-TiO2 absorbed at all wavelengths from 200 to 800 nm. The addition of vanadium generated a new acid site in the framework of TiO2, and the medium acidic site increased with Pt impregnation. The NH3 decomposition increased with the amount of vanadium compared to pure TiO2, and was enhanced with Pt impregnation. NH3 decomposition of 100% was attained over 1.0 wt% Pt/1.0 mol% V-TiO2 after 80 min under illumination with 365 nm light, although about 10% of the ammonia was converted into undesirable NO2 and NO. Various intermediates, such as NO2, -NH2, -NH and NO, were also identified in the Fourier transform infrared (FT-IR) spectra. From the gas chromatography (GC), FT-IR and GC/mass spectroscopy (GC/MS) analyses, partially oxidized NO and NO2 were found to predominate over V-TiO2 and pure TiO2, respectively, while both molecules were reduced over Pt/V-TiO2.

Removal of Fe Impurities on Silicon Surfaces using Remote Hydrogen Plasma (리모트 수소 플라즈마를 이용한 Si 표면 위의 Fe 불순물 제거)

  • Lee, C.;Park, W.;Jeon, B.Y.;Jeon, H.T.;Ahn, T.H.;Back, J.T.;Shin, K.S.;Lee, D.H.
    • Korean Journal of Materials Research
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    • v.8 no.8
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    • pp.751-756
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    • 1998
  • Effects of remote hydrogen plasma cleaning process parameters on the removal of Fe impurities on Si surfaces and the Fe removal mechanism were investigated. Fe removal efficiency is enhanced with decreasing the plasma exposure time and increasing the rf-power. The optimum plasma exposure time and rf-power are 1 min and 100W. respectively, in the range below 10 min and 100W. Fe removal efficiency is better under lower pressures than higher pressures, and the optimum $\textrm{H}_2$ flow rate was found to be 20 and 60sccm, respectively, under a low and a high pressure. The post-RHP(remote hydrogen plasma) annealing enhanced metallic contaminants removal efficiency, and the highest efficiency was achieved at $600^{\circ}C$. According to the AFM analysis results Si surface roughness was improved by 30-50%, which seems to be due to the removal of particles by the plasma cleaning. Also. Fe impurities removal mechanisms by remote hydrogen plasma are discussed.

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A Study on the Application of Physical Soil Washing Technology at Lead-contaminated Shooting Range in a Closed Military Shooting Range Area (폐 공용화기사격장 내 납오염 사격장 군부지의 물리적 토양세척정화기술 적용성 연구)

  • Jung, Jaeyun;Jang, Yunyoung
    • Journal of Environmental Impact Assessment
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    • v.28 no.5
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    • pp.492-506
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    • 2019
  • Heavy metal contaminants in the shooting range are mostly present in a warhead circle or a metal fragment present as a particle, these fine metal particles are weathered for a long period of time is very likely that the surface is present as an oxide or carbon oxide. In particular, lead which is a representative contaminant in the shooting range soil, is present as more fine particles because it increases the softness and is stretched well. Therefore, by physical washing experiment, we conducted a degree analysis, concentration of heavy metals by cubic diameter, composition analysis of metallic substances, and assessment of applicability of gravity, magnetism and floating selection. The experimental results FESEM analysis and the measurement results lead to the micro-balance was confirmed thatthe weight goes outless than the soil ofthe same size in a thinly sliced and side-shaped structure according to the dull characteristics it was confirmed that the high specific gravity applicability. In addition, the remediation efficiency evaluation results using a hydrocyclone applied to this showed a cumulative remediation efficiency of 71%,twice 80%, 3 times 91%. On the other hand, magnetic sifting showed a low efficiency of 17%,floating selection -35mesh (0.5mm)target soil showed a relatively high efficiency to 39% -10mesh (2mm) efficiency was only 16%. The target treatment diameter of soil washing should be 2mm to 0.075mm, which is applied to the actual equipment by adding an additional input classification, which would require management as additional installation costs and processes are constructed. As a result, it is found that the soilremediation of shooting range can be separately according to the size of the warhead. The size is larger than the gravel diameter to most 5.56mm, so it is possible to select a specific gravity using a high gravity. However, the contaminants present in the metal fragments were found to be processed by separating using a hydrocyclone of the soil washing according to the weight is less than the soil of the same particle size in a thinly fragmented structure.