64 research outputs found
PM2.5 dispersion in Venice area: a model validation
No full textA multidisciplinary project was developed with the aim of better understand PM2.5 primary sources and secondary aerosol formation and compositions. A model system was used to simulate four periods during different seasons in 2009 for which both organic and inorganic measured data were available. Input data were estimated and formatted as requested by models. Measured and predicted data were compared for the three stations and during different seasons in order to test model performance
EPHECT II: Exposure assessment to household consumer products
No full textWithin the framework of the EPHECT project (Emissions, exposure patterns and health effects of consumer products in the EU), irritative and respiratory health effects were assessed in relation to acute and long-term exposure to key and emerging indoor air pollutants emitted during household use of selected consumer products. In this context, inhalation exposure assessment was carried out for six selected 'target' compounds (acrolein, formaldehyde, benzene, naphthalene, d-limonene and α-pinene). This paper presents the methodology and the outcomes from the micro-environmental modelling of the 'target' pollutants following single or multiple use of selected consumer products and the subsequent exposure assessment. The results indicate that emissions from consumer products of benzene and α-pinene were not considered to contribute significantly to the EU indoor background levels, in contrast to some cases of formaldehyde and d-limonene emissions in Eastern Europe (mainly from cleaning products). The group of housekeepers in East Europe appears to experience the highest exposures to acrolein, formaldehyde and benzene, followed by the group of the retired people in North, who experiences the highest exposures to naphthalene and α-pinene. High exposure may be attributed to the scenarios developed within this project, which follow a 'most-representative worst-case scenario' strategy for exposure and health risk assessment. Despite the above limitations, this is the first comprehensive study that provides exposure estimates for 8 population groups across Europe exposed to 6 priority pollutants, as a result of the use of 15 consumer product classes in households, while accounting for regional differences in uses, use scenarios and ventilation conditions of each region
Hydrodynamic behavior of a bare rod bundle. [LMFBR]
No full textThe temperature distribution within the rod bundle of a nuclear reactor is of major importance in nuclear reactor design. However temperature information presupposes knowledge of the hydrodynamic behavior of the coolant which is the most difficult part of the problem due to complexity of the turbulence phenomena. In the present work a 2-equation turbulence model--a strong candidate for analyzing actual three dimensional turbulent flows--has been used to predict fully developed flow of infinite bare rod bundle of various aspect ratios (P/D). The model has been modified to take into account anisotropic effects of eddy viscosity. Secondary flow calculations have been also performed although the model seems to be too rough to predict the secondary flow correctly. Heat transfer calculations have been performed to confirm the importance of anisotropic viscosity in temperature predictions. All numerical calculations for flow and heat have been performed by two computer codes based on the TEACH code. Experimental measurements of the distribution of axial velocity, turbulent axial velocity, turbulent kinetic energy and radial Reynolds stresses were performed in the developing and fully developed regions. A 2-channel Laser Doppler Anemometer working on the Reference mode with forward scattering was used to perform the measurements in a simulated interior subchannel of a triangular rod array with P/D = 1.124. Comparisons between the analytical results and the results of this experiment as well as other experimental data in rod bundle array available in literature are presented. The predictions are in good agreement with the results for the high Reynolds numbers
Real time, high resolution regional weather and air quality forecasting system in West Macedonia, Greece
No full textMODELLING OF ATMOSPHERIC FLOW AND DISPERSION IN THE WAKE OF A CYLINDRICAL OBSTACLE
No full textThis paper presents computational simulations of atmospheric dispersion experiments conducted around isolated
obstacles in the field. The computational tool used for the simulations was the code ADREA-HF, which was especially developed
for the simulation of the dispersion of positively or negatively buoyant gases in complicated geometries. The field experiments
simulated involve a single cylindrical obstacle normal to the mean wind direction and two upwind sources of ammonia and propane,
with the ammonia source located at different lateral positions (Mavroidis et al., 2003). Concentrations and concentration fluctuations
for both gases were calculated by the model and compared with the experimental results to evaluate the model performance.
Specific characteristics of dispersion were investigated using the computational tool. Comparisons of experimental and model
results with the case of dispersion around an isolated cubical obstacle are also presented and discussed
Evaluation of probability distributions for concentration fluctuations in a building array
No full textAN EVALUATION OF THE UoWM MM5-SMOKE-CMAQ MODELING SYSTEM FOR WESTERN MACEDONIA
No full textThe University of Western Macedonia (UoWM) has recently set up an operational system for predicting air quality in the
Florina–Ptolemais–Kozani basin in Western Macedonia, Greece. This is a mountainous basin where around 65% of the total energy
production of Greece takes place in lignite power plants. The concentrations of PM10 is the main air quality concern in the region,
and the high particulate matter levels observed are attributed to the activities related to power generation. The system set up by the
UoWM makes use of software such as MM5 for weather prediction, SMOKE for emissions processing, and CMAQ for air quality
prediction. This paper describes a preliminary effort to evaluate the system by comparing its predictions against ground station
observations for a selection of days of the 2007 summer period
- …
