• Title/Summary/Keyword: Spray method

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Methodologies for Inhalation Exposure Assessment of Engineered Nanomaterial-containing Consumer Spray Products (분사형 소비자 제품 중 나노 물질의 흡입 노출 평가 방법)

  • Park, Jihoon;Park, Mijin;Yoon, Chungsik
    • Journal of Environmental Health Sciences
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    • v.45 no.5
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    • pp.405-425
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    • 2019
  • Objective: This study aimed to review the methodologies for evaluation of consumer spray products containing engineered nanomaterials (ENM), particularly focusing on inhalation exposure. Method: Literature on the evaluation methods for aerosolized ENM exposure from consumer spray products were collected through academic web searching. Common methodologies used in the literature, including research reports and academic articles, were also introduced. Results: The number of ENM-containing products have shown a considerable increase over recent years, from 54 in 2005 to 1,827 in 2018. Currently there is still discussion over the existing regulations with regard to product safety. Analysis of both ENM suspensions in the products and their aerosols is important for risk assessment. Comparison between the phases suggests how the size and concentration of particles change during the spray process. To analyze the ENM suspensions, dynamic light scattering, electron microscopy techniques, and inductively coupled plasma with mass spectrometry were used. In the aerosol monitoring, direct-reading instruments have been used to monitor the aerosols and conventional active sampling is used together to supplement the lack of real-time monitoring. There are also some models for estimating inhalation exposure. These models may be used to estimate mass exposure to nanomaterials contained in consumer products. Conclusion: Although there is no standardized method to evaluate ENM exposure from consumer products, many concerns about ENM have emerged. Every potential measure to reduce exposure to ENM from spray product use should be implemented through a precautionary recognition.

Experimental Study on Evaluation of Bond Strength after Ozone Treatment and Ozone Resistance of Concrete Metal Spray Coating for Advanced Water Treatment (고도정수처리용 콘크리트 금속용사 피막의 내오존성 및 오존처리 후 부착강도 평가에 관한 실험적 연구)

  • Park, Jin-Ho;Jang, Hyun-O;Lee, Han-Seung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.4
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    • pp.68-75
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    • 2018
  • The introduction of advanced water treatment facilities has increased as the conventional purification method cannot remove the substance clearly. However, the internal waterproofing and Anticorrosion materials of the advanced water treatment facility using ozone deteriorate due to the oxidation power of ozone and affects the concrete, which causes a decrease in durability. This study is to evaluate the ozone resistance according to the type of spray metal and the surface treatment method of the coating, and the bond strength after ozone treatment in order to develope a finishing method to prevent deterioration of concrete structure of water treatment facility using metal spraying method as a way to construct metal panel with excellent ozone resistance and chemical resistance by an easier way than the previous. The Experimental results show that spray metal Ti has superior ozone resistance even after spraying. It is considered to be the most suitable method for ozone resistance and bond performance by finishing using Teflon sealing as surface treatment method.

Residue analysis of spinetoram and spinosad on paprika leaf using the modified QuEChERS pre-treatment methods

  • Kim, Young-Shin;Yang, Jun-Young;Jin, Na-Young;Yu, Yong-Man;Youn, Young-Nam;Lim, Chi-Hwan
    • Korean Journal of Agricultural Science
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    • v.44 no.4
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    • pp.487-494
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    • 2017
  • Spinosad and spinetoram are widely used insecticides for the control of lepidopteran larvae, leaf miners, and thrips; however, they might also have low toxicity toward beneficial insects like bees. Because these pesticides are easily photolyzed by ultraviolet radiation, the QuEChERS method, with its simple pretreatment procedure, is often used for analyzing residues of spinosad and spinetoram. The present study performed a residue analysis using a modified QuEChERS method by pretreating with ammonium salt. The limit of detection (LOD) of the modified method was 0.05 mg/kg and the limit of quantification (LOQ) was 0.25 mg/kg. The coefficient of determination (R2) for the calibration curve was 0.999. Also, we examined any change in the adhesion of spinosad and spinetoram on the plants depending on a spray volume. The adhesion was approximately 70% when the spray volume was increased from 60 L to 120 L per 10 a whereas the adhesion was approximately 37% when the spray volume was increased from 125 L to 250 L. This showed that the amount of adhesion decreased with the higher spray volume. The efficacy result of spinetoram was that over 90% of Frankliniella occidentalis was controlled with the application volume of 125 L per 10 a. Therefore, the result of this study indicates that control of insects is effective and sufficient with a spray volume of 125 L per 10 a in paprika cultivation facilities.

Reduction of a Numerical Grid Dependency in High-pressure Diesel Injection Simulation Using the Lagrangian-Eulerian CFD Method (Lagrangian-Eulerian 기법을 이용한 고압 디젤 분무 시뮬레이션의 수치해석격자 의존성 저감에 관한 연구)

  • Kim, Sa-Yop;Oh, Yun-Jung;Park, Sung-Wook;Lee, Chang-Sik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.20 no.1
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    • pp.39-45
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    • 2012
  • In the standard CFD code, Lagrangian-Eulerian method is very popular to simulate the liquid spray penetrating into gaseous phase. Though this method can give a simple solution and low computational cost, it have been reported that the Lagrangian spray models have numerical grid dependency, resulting in serious numerical errors. Many researches have shown the grid dependency arise from two sources. The first is due to unaccurate prediction of the droplet-gas relative velocity, and the second is that the probability of binary droplet collision is dependent on the grid resolution. In order to solve the grid dependency problem, the improved spray models are implemented in the KIVA-3V code in this study. For reducing the errors in predicting the relative velocity, the momentum gain from the gaseous phase to liquid particles were resolved according to the gas-jet theory. In addition, the advanced algorithm of the droplet collision modeling which surmounts the grid dependency problem was applied. Then, in order to validate the improved spray model, the computation is compared to the experimental results. By simultaneously regarding the momentum coupling and the droplet collision modeling, successful reduction of the numerical grid dependency could be accomplished in the simulation of the high-pressure injection diesel spray.

Effect of Drying Methods on the Production of Graphenes Oxide Powder Prepared by Chemical Exfoliation (화학적 박리법으로 제조된 산화그래핀 분말의 건조방법에 따른 물성 비교)

  • Rho, Sangkyun;Noh, Kyung-Hun;Eom, Sung-Hun;Hur, Seung Hyun;Lim, Hyung Mi
    • Korean Journal of Materials Research
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    • v.23 no.10
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    • pp.592-598
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    • 2013
  • Graphene oxide powders prepared by two different drying processes, freeze drying and spray drying, were studied to compare the effect of the drying method on the physical properties of graphene oxide powder. The graphene oxide dispersion was prepared from graphite by chemical delamination with the aid of sulfuric acid and permanganic acid, and the dispersion was further washed and re-dispersed in a mixed solvent of water and isopropyl alcohol. A freeze drying method can feasibly minimize damage to the sample, but it requires a long process time. In contrast, spray drying is able to remove a solvent in a relatively short time, though this process requires exposure to a high temperature for a rapid evaporation of the solvent. The powders prepared by freeze drying and spray drying were characterized and compared by Raman spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and by an elemental analysis. The graphene oxide powders showed similar chemical compositions; however, the morphologies of the powders differed in that the graphene oxide prepared by spray drying had a winkled morphology and a higher apparent density compared to the powder prepared by freeze drying. The graphene oxide powders were reduced at 900C in an atmosphere of N2. The effect of the drying process on the properties of the reduced graphene oxide was examined by SEM, TEM and Raman spectroscopy.

Fabrication of Far-Infrared Ceramic/AI Composite Powders by Spray Drying Method and Characteristics of the Plasma Sprayed Coating Layer (분무건조법에 의한 용사용 원적외선 세라믹/AI 복합분말제조 및 용사층의 특성)

  • Hong, Seong-Jun;Kim, Byeong-Hui;Min, Jae-Ung;Song, Byeong-Gil;No, Jae-Seung;Seo, Dong-Su
    • Korean Journal of Materials Research
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    • v.9 no.12
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    • pp.1205-1210
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    • 1999
  • Far infrared ceramic/aluminum composite powders for thermal spray were fabricated by spray drying method and investigated the characteristics of the plasma sprayed coating layers, I.e. microstructure, phases, thermal shock resistance and spectral emissivity. The shape of the spray dried composite powder was spherical and the particle size distribution was 34~105μm. Aluminum was distributed homogeneously in the spray dried composite powder. Spectral emissivity of the plasma sprayed coating layer ranges from 3 to 14μm whereas spectral emissivity of the raw ceramic powder ranges from 8 to 14μm. And then spectral emissivity of the coatings was better than that of the raw powder but spectral emissivity was decreased with increasing aluminum content. It was found that aluminum content ranging from 20 to 30wt% was suitable for fabricating far-infrared radiator by plasma spraying method.

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Characteristics in Microstructure of Particle Reinforced Al Matrix Composites Fabricated by Spray-Cast Forming Process (분사주조한 입자강화 알루미늄 복합재료의 미세조직 특성)

  • Park, Chong-Sung;Lee, In-Woo;Kim, Myung-Ho
    • Journal of Korea Foundry Society
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    • v.14 no.6
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    • pp.530-540
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    • 1994
  • Aluminium-silicon alloy(JIS AC8A) matrix composites reinforced with SiC particles were fabricated by spray-cast forming process, and the microstructure of powders and preforms produced were studied by using an optical and scanning electron microscopy. SiC particles were co-sprayed by mixed phase injection method during the spray casting process. Most of the composite powders formed by this mixed phase injection method exhibit morphology of particle-embedded type, and some exhibits the morphology of particle attached type due to additional attachment of the SiC particles on the surface of the powders in flight. The preforms deposited were resulted in dispersed type microstructure. The pre-solidified droplets and the deposited preform of SiC-reinforced aluminium alloy exhibit finer equiaxed grain size than that of unreinforced aluminium alloy. Eutectic silicons of granular type are crystallized at the corner of the aluminum grains in the preforms deposited, and some SiC particles seem to act as nucleation sites for primary/eutectic silicon during solidification. Such primary/eutectic silicons seem to retard grain growth during the continued spray casting process. It is envisaged from the microstructural observations for the deposited preform that the resultant distribution of SiC injected particles in the Al-Si microsturcture is affected by the amount of liquid phase in the top part of the preform and by the solidification rate of the preform deposited.

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Microencapsulation of Lactobacillus plantarum DKL 109 using External Ionic Gelation Method

  • Chun, Honam;Kim, Cheol-Hyun;Cho, Young-Hee
    • Food Science of Animal Resources
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    • v.34 no.5
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    • pp.692-699
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    • 2014
  • The aim of this study was to apply the external ionic gelation using an atomizing spray device comprised of a spray gun to improve the viability of Lactobacillus plantarum DKL 109 and for its commercial use. Three coating material formulas were used to microencapsulate L. plantarum DKL 109: 2% alginate (Al), 1% alginate/1% gellan gum (Al-GG), and 1.5% alginate/3% gum arabic (Al-GA). Particle size of microcapsules was ranged from 18.2 to 23.01μm depending on the coating materials. Al-GA microcapsules showed the highest microencapsulation yield (98.11%) and resulted in a significant increase in survivability of probiotic in a high acid and bile environment. Encapsulation also improved the storage stability of cells. The viability of encapsulated cells remained constant after 1-mon storage at ambient temperature. The external ionic gelation method using an atomizing spray device and the Al-GA seems to be an efficient encapsulation technology for protecting probiotics in terms of scale-up potential and small microcapsule size.

The Effect of Injection Timing and Cavity Geometry on Fuel Mixture Formation in a Central Injected DI Gasoline Engine (중앙 분사방식의 직분식 가솔린 기관에서 연료 혼합기 형성에 미치는 분사시기와 캐비티 형상의 영향)

  • 김태안;강정중;김덕줄
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.2
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    • pp.32-38
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    • 2004
  • This study was performed to investigate the behavior of liquid and vapor phase of fuel mixtures with different piston cavity diameters in a optically accessible engine. The conventional engine was modified as Central Injected DI gasoline engine with swirl motion. Two dimensional spray fluorescence images of liquid and vapor phase were acquired to analyze spray behavior and fuel distribution inside of cylinder using exciplex fluorescence method. Piston cavity geometries were set by Type S, M and L. The results obtained are as follows. In the spray formation after SOI, the cone angle and width of the spray were decreased at late injection timing. With a fuel injection timing of BTDC 180C, fuel was not greatly affected in a piston cavity but generally distributed as homogeneous mixture in the cylinder. With a fuel injection timings of BTDC 90C and 60C, fuel mixture was widely distributed in near the cavity center. As a injection timing was late in the compression stroke, residual width of fuel mixture was narrow in proportion to piston cavity.