نتایج جستجو برای: ozone deposition velocity

تعداد نتایج: 252131  

2015
A. Moravek P. Stella T. Foken I. Trebs

Dry deposition of peroxyacetyl nitrate (PAN) is known to have a phytotoxic impact on plants under photochemical smog conditions, but it may also lead to higher productivity and threaten species richness of vulnerable ecosystems in remote regions. However, underlying mechanisms or controlling factors for PAN deposition are not well understood and studies on dry deposition of PAN are limited. In ...

2008
M. ENGARDT

As part of the model intercomparison study MICS Asia II, the Swedish MATCH model was set up for Southeast and East Asia. In that study, the comprehensive photochemistry scheme of MATCH was used for the first time in Asia. The current work focuses on results of surface ozone from the MATCH model simulations falling outside the model intercomparison study. Model results of surface ozone concentra...

2004
A. H. Goldstein M. McKay M. R. Kurpius G. W. Schade A. Lee R. Holzinger R. A. Rasmussen

[1] Ecosystem ozone uptake can occur through stomatal and surface deposition and through gas phase chemical reactions. In a California pine forest, thinning dramatically enhanced both monoterpene emission and ozone uptake. These simultaneous enhancements provide strong evidence that ozone reactions with unmeasured biogenically emitted volatile organic compounds (BVOCs) dominate ozone uptake, an...

2013
Richard J Payne Carly J Stevens Nancy B Dise David J Gowing Michael G Pilkington Bridget A Emmett Michael R Ashmore

17 Air pollutants are recognised as important agents of ecosystem change but few studies consider 18 the effects of multiple pollutants and their interactions. Here we use ordination, constrained cluster 19 analysis and indicator value analyses to identify potential environmental controls on species 20 composition, ecological groupings and indicator species in a gradient study of UK acid grassl...

2014
Lanxia Cheng Xiaoye Qin Antonio T. Lucero Angelica Azcatl Jie Huang Robert M. Wallace Kyeongjae Cho Jiyoung Kim

We present an Al2O3 dielectric layer on molybdenum disulfide (MoS2), deposited using atomic layer deposition (ALD) with ozone/trimethylaluminum (TMA) and water/TMA as precursors. The results of atomic force microscopy and low-energy ion scattering spectroscopy show that using TMA and ozone as precursors leads to the formation of uniform Al2O3 layers, in contrast to the incomplete coverage we ob...

2005
E. Simon F. X. Meixner

A one-dimensional multi-layer scheme describing the coupled exchange of energy and CO2, the emission of isoprene and the dry deposition of ozone is applied to a rain forest canopy in southwest Amazonia. The model was constrained using mean diel cycles of micrometeorological quantities observed during two periods in the wet and dry season 1999. Calculated net fluxes and concentration profiles fo...

Journal: :international journal of occupational hygiene 0
mohammad javad jafari department of occupational health, faculty of health, university of shahid beheshti, tehran, iran. behnaz shafiei department of occupational health, faculty of health, university of shahid beheshti, tehran, iran. mansour rezazadeh azari department of occupational health, faculty of health, university of shahid beheshti, tehran, iran. mohammad movahhedi department of occupational health, faculty of health, university of shahid beheshti, tehran, iran.

welders may suffer from welding fumes generated during the process if the ventilation systems are improperly applied. the objective of the present work was to study the mitigation of air pollutants at welding stations, using different ventilation scenarios. four air pollutants including iron oxide, respirable dust, ozone, and carbon monoxide were measured during four different ventilation scena...

An experiment set-up is used to study wall deposition rate of particles on a rough surface in a turbulent channel flow. Deposition velocities for three classes of particles, namely, spherical glass particles, irregular shape polymer particles, and fibrous silicon particles are studied. The particle concentration at the test section was measured with the aid of an isokinetic probe in conjunction...

2017
R. Osada S. Ogata T. Segawa

Abstract—Dielectric barrier discharge plasma actuators (DBD-PAs) have been developed for active flow control devices. However, it is necessary to reduce ozone produced by DBD toward practical applications using DBD-PAs. In this study, variations of ozone concentration, flow velocity, power consumption were investigated by changing exposed electrodes of DBD-PAs. Two exposed electrode prototypes ...

2004
Laurens Ganzeveld Jos Lelieveld

[1] A single-column chemistry and climate model has been used to study the impact of deforestation in the Amazon Basin on atmospheric chemistry. Over deforested areas, daytime ozone deposition generally decreases strongly except when surface wetness decreases through reduced precipitation, whereas nocturnal soil deposition increases. The isoprene and soil nitric oxide emissions decrease althoug...

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