نتایج جستجو برای: fine particles

تعداد نتایج: 259434  

2017
Kasper E. Brodersen Kathrine J. Hammer Verena Schrameyer Anja Floytrup Michael A. Rasheed Peter J. Ralph Michael Kühl Ole Pedersen

HIGHLIGHTS: Sedimentation of fine sediment particles onto seagrass leaves severely hampers the plants' performance in both light and darkness, due to inadequate internal plant aeration and intrusion of phytotoxic H2S. Anthropogenic activities leading to sediment re-suspension can have adverse effects on adjacent seagrass meadows, owing to reduced light availability and the settling of suspended...

The circulation of dust suspended in the air is among the most significant environmental problems in the various regions of the world. However, the primary source of the dust present in the atmosphere is fine-grained particles and These tiny particles are more frequent in arid and semi-arid areas. The Tabas Masina Playa in Iran is one of the regions prone to dust production due to warm and dry ...

2014
Wen-cai Zhang Yan-ge Wang Zheng-feng Zhu Fang-qin Wu Yu-dong Peng Zhu-yue Chen Jin-hua Yang Jing-jing Wu Yi-tian Lian Mei-an He Tang-chun Wu Long-xian Cheng

OBJECTIVE To investigate the role of CD4(+)CD25(+) T cells (Tregs) in protecting fine particulate matter (PM-) induced inflammatory responses, and its potential mechanisms. METHODS Human umbilical vein endothelial cells (HUVECs) were treated with graded concentrations (2, 5, 10, 20, and 40 µg/cm(2)) of suspension of fine particles for 24h. For coculture experiment, HUVECs were incubated alone...

Journal: :Journal of Occupational Medicine and Toxicology (London, England) 2009
Martha Patricia Sierra-Vargas Alberto Martin Guzman-Grenfell Salvador Blanco-Jimenez Jose David Sepulveda-Sanchez Rosa Maria Bernabe-Cabanillas Beatriz Cardenas-Gonzalez Guillermo Ceballos Juan Jose Hicks

BACKGROUND The Mexico City Metropolitan Area is densely populated, and toxic air pollutants are generated and concentrated at a higher rate because of its geographic characteristics. It is well known that exposure to particulate matter, especially to fine and ultra-fine particles, enhances the risk of cardio-respiratory diseases, especially in populations susceptible to oxidative stress. The ai...

2017
T L Huang G L Wu X Huang N Hansen

An Al-1.08 vol.%Si alloy was cold rolled to a reduction of 98% (vM = 4.5) and then annealed at different temperatures up to 210C (0.52 Tm) for different times. The deformed structure is characterized by a nanoscale lamellar structure with the presence of Si particles of coarse (> 1m), medium (100 nm – 1 m) and fine (< 100 nm) sizes in the microstructure. Deformation zones are formed around ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور مرکز - دانشکده علوم 1391

سنتز پلیمرهای کوئوردیناسیونی جدید از لیگاندهای 2-آمینو نیکوتینیک اسید، 2-کینولین کربوکسیلیک اسید، 2-پیرازین کربوکسیلیک اسید در ابعاد توده، با روش گرایان دمایی و با استفاده از شاخه ی جانبی انجام شده است، این پلیمرها توسط روش طیف سنجی ir شناسایی و پایداری گرمایی آن ها توسط تجزیه های وزن سنجی حرارتی (tga) و تجزیه ی گرمایی تفاضلی (dta) بررسی شده است. در ادامه، ساختار این ترکیبات توسط بلورنگاری پرتو...

Magnetic, Mössbauer, and I.R. studies of nanosize particles of Fe and Co species dispersed in a cage of aluminosilicates structure, in relation to syngas (CO+H2) Fischer Tropsch conversion. The difference in the catalytic activity of such species have shown dependancy on their degree of dispersion. The carbonyl impregnation gave ultra-fine Super Paramagnetic Fe3O4, whereas the nitrate impregnat...

Journal: :iranian journal of science and technology (sciences) 2013
g. c. rana

in this paper, the combined effect of suspended (fine dust) particles and rotation on the onset of thermosolutal convection in an elastico-viscous fluid in a porous medium is studied. for the porous medium, the brinkman model is employed and rivlin-ericksen model is used to characterize viscoelastic fluid. by applying normal mode analysis method, the dispersion relation has been derived and sol...

2007
Prashant Kumar Paul Fennell Rex Britter

INTRODUCTION Current regulations for atmospheric particulate matter include PM10 and PM2.5 mass concentration. Fine particulates (those below 1000 nm) are not included in the regulatory limits. These particles contribute significantly to particle number concentration (PNC), but little to particle mass concentration. It is widely hypothesised that number concentrations of fine particles are bett...

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