Characterization of carbon fibrous material from platanus achenes as platinum catalysts support

Carbon materials with developed porosity are usually used as supports for platinum catalysts. Physico-chemical characteristics of the support influence the properties of platinum deposited and its catalytic activity. In our studies, we deposited platinum on carbon fibrous like materials obtained from platanus seeds - achenes. The precursor was chemically activated with different reagents: NaOH, pyrogallol, and H2O2, before the carbonization process. Platinum was deposited on all substrates to study the influence of the substrate properties on the activity of the catalyst. Carbon materials were characterized by nitrogen adsorption/desorption isotherms measurements, X-ray diffraction, and scanning electron microscopy. It was noticed that the adsorption characteristics of carbon support affected the structure of platinum deposits and thus their activity

Simulation of free turbulent particle-laden jet using Reynolds-stress gas turbulence model

Free two-phase flows occur in many practical applications, such as sprays or particle drying and combustion. This paper deals with mathematical modelling of a free turbulent two-phase jet. A steady, axisymmetric, dilute, monodisperse, particle-laden, turbulent jet injected into a still environment, has been considered. The model treats the gas-phase from an Eulerian standpoint and the motion of particles from a Lagrangian one. Closure of the system of time averaged transport equations has been accomplished by using a Reynolds-stress turbulence model. The particles-fluid interaction has been considered by the PSI-Cell concept. Both the effect of interphase slip and the effect of particle dispersion have been taken into account. Results of the model have been compared with experimental data for axial and radial profiles of gas-phase mean and turbulent quantities and solid-phase mean velocity. Accuracy of model predictions of particle-laden free jet time averaged characteristics as well as turbulence correlation coefficients have been improved. The modelling of observed turbulence anisotropy levels and correlation coefficients need to be carried out with special care. The model has provided insight into the turbulence structure and aerodynamic characteristics of the particle-laden free jet. A brief sensitivity study has been performed as well, indicating that the specification of inlet boundary conditions exerts pronounced effects on predictions. In this paper, the study refers to the effect of the turbulence kinetic energy dissipation rate, while the other inlet boundary conditions have been applied with respect to the referent measurements. (c) 2006 Elsevier Inc. All rights reserved

Comparative analyses of built environment exposures relevant to health of greenhouse gas emissions reduction strategies in Serbia

Paper presents comparative analysis of residential indoor air pollutant concentration change over future specified time horizon, implementing building physical and thermal retrofit measures, thus creating pollution mitigation scenarios for existing Belgrade and Nis housing stock followed by greenhouse gas emission reduction scenarios up to 2050. Regarding specified mitigation scenarios, the set of typical housing unit models has been generated which define existing housing stock of Belgrade and Nis. Extensive monitoring of physical and thermal parameters as well as detailed socio-technical survey of selected households was performed and used as an initial modeling input. Relationship between environment pollution and building performances was investigated, with respect to indoor-outdoor sources of pollution, thermal and physical properties of the stock samples and occupants behavior. As a final output, indoor pollutant concentrations for each of the modelled cases was obtained and validated against the available data. This housing modelling framework has been created in order to develop an assessment of present and future exposure and health impact quantity regarding single/multiple scenario interventions introduced to the housing stock. This paper provides each strategy guidelines for taking measures towards achieving the healthier indoor environments.8th Dubrovnik Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES), Sep 22-27, 2013, Dubrovnik, Croati

PM and CO2 variability and relationship in the different school environments

Indoor air quality (IAQ) is very important for children health and well-being, since children are particularly vulnerable and sensitive to the presence of air pollutants. This study was performed in two naturally ventilated schools located in the same municipality. The first school is located in an urban area, at a residential-industrial site, while the other school is situated in a rural area. School buildings were chosen based on their urban environment features. The measurements were carried out in heating and non-heating periods in duration of five consecutive working days. The objective of the study was to analyze IAQ in the classrooms with special emphasis on levels and diurnal variations of particulate matter (PM10 and PM2.5), carbon dioxide (CO2) and nitrogen dioxide (NO2) in occupied and unoccupied school classrooms. In this paper, the CO2 concentrations were measured at both indoor and outdoor environments. Concentrations of CO2 higher than 1000 ppm were regularly detected in the Classrooms during teaching hours. Indoor concentrations of PM10 were not exceeded the guideline, daily average, value of 50 mu g/m(3). Concentrations of PM2.5 exceeded the guideline daily average value of 25 mu g/m(3) in both school during heating period. Concentrations of NO2 did not exceed the guideline value of 200 mu g/m(3). Ventilation rates were calculated and compared with the prescribed limits. In both occupied and unoccupied periods high correlation between CO2 and PM concentrations was determined

Indoor air pollution, physical and comfort parameters related to schoolchildren's health:Data from the European SINPHONIE study

Substantial knowledge is available on the association of the indoor school environment and its effect among schoolchildren. In the same context, the SINPHONIE (School indoor pollution and health: Observatory network in Europe) conducted a study to collect data and determine the distribution of several indoor air pollutants (IAPs), physical and thermal parameters and their association with eye, skin, upper-, lower respiratory and systemic disorder symptoms during the previous three months. Finally, data from 115 schools in 54 European cities from 23 countries was collected and included 5175 schoolchildren using a harmonized and standardized protocol. The association between exposures and the health outcomes were examined using logistic regression models on individual indoor air pollutants (IAPs); a VOC (volatile organic compound) score defined as the sum of the number of pollutants to which the children were highly exposed (concentration > median of the distribution) in classroom was also introduced to evaluate the multiexposure \u2013 outcome association, while adjusting for several confounding factors. Schoolchildren exposed to above or equal median concentration of PM2.5, benzene, limonene, ozone and radon were at significantly higher odds of suffering from upper, lower airways, eye and systemic disorders. Increased odds were also observed for any symptom (sick school syndrome) among schoolchildren exposed to concentrations of limonene and ozone above median values. Furthermore, the risks for upper and lower airways and systemic disorders significantly increased with the VOCs score. Results also showed that increased ventilation rate was significantly associated with decreased odds of suffering from eye, skin disorders whereas similar association was observed between temperature and upper airways symptoms. The present study provides evidence that exposure to IAPs in schools is associated with allergic and respiratory symptoms in children. Further investigations are needed to confirm our findings