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121.
《Analytical letters》2012,45(6):475-482
Abstract A simple method involving ion chromatography with ultraviolet detection (IC-UV) is applied to the determination of benzoic acid in atmospheric samples. The detection limit is 10 nanograms. Validation and interference studies are described. The application of the IC-UV method to other aromatic acids including nitrophenols is briefly discussed. 相似文献
122.
Guillaume Falgayrac Nathalie Chrot‐Kornobis Virginie de Broucker Sbastien Hulo Jean‐Louis Edm Annie Sobaszek Guillaume Penel 《Journal of Raman spectroscopy : JRS》2011,42(6):1484-1487
A new method for the analysis of particulate matter in lungs is proposed. It combines the exhaled breath condensate technique and Raman spectroscopy. The sampling method is noninvasive, which is suitable for the detection of occupational exposure to dust. The chemical composition of dust particles is assessed by Raman microspectroscopy. The effectiveness of this method as a means of identifying markers of occupational exposure to mica dust is evaluated. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
123.
Shi Jin Peter Minev Krishnaswamy Nandakumar 《International Journal of Computational Fluid Dynamics》2013,27(5):427-437
Particulate flow is of great importance from both the scientific and engineering points of view. Owing to the complexity of particle-flow interactions, direct numerical simulations (DNS) of inertial particulate flow with finite-size particles have been limited to a very small number of particles, while the industrial applications involve larger numbers with many orders of magnitude. This article presents a parallel implementation of a fictitious domain method for the DNS of particulate flows. The method is thoroughly tested and its parallel performance on distributed memory clusters is evaluated on a large-scale problem. Finally, we present the results for the separation of 21,336 particles of two different densities in a viscous fluid. Although there is still a significant gap between DNS and the industrial applications, the present algorithm allows to simulate significantly large number of particles so that a meaningful statistical analysis can be performed. This will help in the development of new closure relations for the averaged models of multiphase flows. 相似文献
124.
125.
R. C. Jasan R. R. Plá R. Invernizzi M. Dos Santos 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(1):101-105
PM10 and PM2.5 samples were taken using a Gent sampler to characterize the atmospheric aerosol of Buenos Aires metropolitan
area. A total of 114 samples were collected from October 2005 to October 2006 at one urban site, every third day, for 24 h.
Samples were analyzed by neutron activation, and black carbon and mass concentration were determined. In both fractions, elemental
and gravimetric mass concentrations were compared with historical data. Enrichment factors, backward trajectories and factor
analysis were calculated. The attribution of pollution sources is discussed. 相似文献
126.
对碳酸氢钠溶液中微粒浓度作了定性分析,发现了碳酸氢钠溶液浓度的3个临界点,预测溶液中微粒浓度大小顺序。通过定量计算求得碳酸氢钠3个临界点的溶液浓度,3个临界点将碳酸氢钠溶液浓度分成4个范围,得出在每个浓度范围内相应的微粒浓度大小顺序。 相似文献
127.
二维液桥计算模型及湿颗粒材料离散元模拟 总被引:2,自引:0,他引:2
本文研究了二维情况两直接相邻颗粒间液体以液桥形式存在时的液桥临界断裂距离及液桥力的计算过程。导出了用颗粒半径、三相接触角和液桥体积表示的二维液桥临界断裂距离拟合公式及两个接触或非接触颗粒间液桥毛细力随液桥体积的变化关系。引入Voronoi胞元计算定义基于参考颗粒介观结构的物质点的平均饱和度。提出了考虑液桥效应的二维湿颗粒离散元模型,并用以模拟不同初始均匀饱和度下湿颗粒集合体中的吸力效应,验证其有效捕捉以应变局部化为特征的破坏模式的能力。 相似文献
128.
129.
《Particuology》2023
The effects of superficial gas velocity and mechanical stirring speed on the precise regulation of flow regimes for cohesive SiO2 powders (mean diameter is 16 μm) were experimentally investigated in a stirring-assisted fluidized bed. The results showed that compared with the agglomerates formed in the non-assisted fluidization of cohesive SiO2 powders, the introduction of mechanical stirring could effectively reduce the size of agglomerates and well disperse the agglomerates during fluidization. The best regulation range of agglomerate particulate fluidization can be achieved at 600 rpm when agglomerate sizes were reduced to below 200 μm. Further investigation based on the operational phase diagram revealed that transformations of flow regimes were dominated by both stirring speed and gas velocity. The stirring applied enlarges the operational range of agglomerate particulate fluidization (APF) with a delayed onset of bubbling for cohesive particles. However, the exorbitant speed increases the collision velocity and contact area between small agglomerates, which results in the formation of unstable agglomerates and the whirlpool of powder. 相似文献
130.
Xinyu Chen Dong Im Kim Hi-Gyu Moon Minchul Chu Kyuhong Lee 《Molecules (Basel, Switzerland)》2022,27(9)
Exposure to particulate matter (PM) is related to various respiratory diseases, and this affects the respiratory immune system. Alveolar macrophages (AMs), which are defenders against pathogens, play a key role in respiratory inflammation through cytokine production and cellular interactions. Coconut oil demonstrates antioxidant and anti-inflammatory properties, and it is consumed worldwide for improved health. However, reports on the protective effects of coconut oil on the PM-induced respiratory immune system, especially in AMs, are limited. In this study, we generated artificial PM (APM) with a diameter approximately of 30 nm by controlling the temperature, and compared its cytotoxicity with diesel exhaust particles (DEP). We also investigated the antioxidant and anti-inflammatory effects of coconut oil in APM– and DEP–stimulated AMs, and the underlying molecular mechanisms. Our results showed that APM and DEP had high cytotoxicity in a dose-dependent manner in AMs. In particular, APM or DEP at 100 μg/mL significantly decreased cell viability (p < 0.05) and significantly increased oxidative stress markers such as reactive oxygen species (p < 0.01); the GSSH/GSH ratio (p < 0.01); and cytokine production, such as tumor necrosis factor-α (p < 0.001), interleukin (IL)-1β (p < 0.001), and IL-6 (p < 0.001). The expression of the genes for chemokine (C-X-C motif) ligand-1 (p < 0.05) and monocyte chemoattractant protein-1 (p < 0.001); and the proteins toll-like receptor (TLR) 4 (p < 0.01), mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (p < 0.001), p38 (p < 0.001); and extracellular receptor-activated kinase (p < 0.001), were also upregulated by PM. These parameters were reversed upon treatment with coconut oil in APM– or DEP–stimulated AMs. In conclusion, coconut oil can reduce APM– or DEP–induced inflammation by regulating the TLR4/MAPK pathway in AMs, and it may protect against adverse respiratory effects caused by PM exposure.Exposure to particulate matter (PM) is related to various respiratory diseases, and this affects the respiratory immune system. Alveolar macrophages (AMs), which are defenders against pathogens, play a key role in respiratory inflammation through cytokine production and cellular interactions. Coconut oil demonstrates antioxidant and anti-inflammatory properties, and it is consumed worldwide for improved health. However, reports on the protective effects of coconut oil on the PM-induced respiratory immune system, especially in AMs, are limited. In this study, we generated artificial PM (APM) with a diameter approximately of 30 nm by controlling the temperature, and compared its cytotoxicity with diesel exhaust particles (DEP). We also investigated the antioxidant and anti-inflammatory effects of coconut oil in APM– and DEP–stimulated AMs, and the underlying molecular mechanisms. Our results showed that APM and DEP had high cytotoxicity in a dose-dependent manner in AMs. In particular, APM or DEP at 100 μg/mL significantly decreased cell viability (p < 0.05) and significantly increased oxidative stress markers such as reactive oxygen species (p < 0.01); the GSSH/GSH ratio (p < 0.01); and cytokine production, such as tumor necrosis factor-α (p < 0.001), interleukin (IL)-1β (p < 0.001), and IL-6 (p < 0.001). The expression of the genes for chemokine (C-X-C motif) ligand-1 (p < 0.05) and monocyte chemoattractant protein-1 (p < 0.001); and the proteins toll-like receptor (TLR) 4 (p < 0.01), mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (p < 0.001), p38 (p < 0.001); and extracellular receptor-activated kinase (p < 0.001), were also upregulated by PM. These parameters were reversed upon treatment with coconut oil in APM– or DEP–stimulated AMs. In conclusion, coconut oil can reduce APM– or DEP–induced inflammation by regulating the TLR4/MAPK pathway in AMs, and it may protect against adverse respiratory effects caused by PM exposure. 相似文献