Studies of aerosol particle formation from various sources using ion and electron beam analytical techniques.

The thesis presents the results of studies of aerosol particle formation using ion and electron beam analytical techniques. The sources of aerosol particle formation studied are the following: 1. production of primary aerosol particles in the high Arctic region during summers 2. emission of ultrafine aerosol particles from wear on the road-tire interface 3. emission of aerosol particles from district heating units operating on three commonly-used biofuels. A source of primary and nearly hydrophobic aerosol particles within the Arctic pack ice region during summers with a composition similar to that of average crustal rock was identified. Wear on the road-tire interface was found to generate numerous ultrafine aerosol particles of varying morphology. The particle number emission factors per vehicle and kilometer driven are similar in magnitude to the tail-pipe exhaust emissions obtained by use of modern engine technology. Particle emissions from the combustion of biomass were characterized in terms of their elemental composition and particle formation mechanisms. List of papers in this dissertation Paper I: Aerosol particle elemental size distributions during the Arctic Ocean expedition in the summer of 2001. Paper II: Summer high Arctic aerosol particles classified using Transmission Electron Microscopy. Paper III: Traffic-generated emissions of ultra fine particles from the road surface-tire interface. Paper IV: Particle emissions from district heating units operation on three commonly used biofuels. Paper V: Laboratory and field test of a method for high-temperature characterization of fly ash and fly ash precursors

The Effect of Changing Policies to Increase the Birth Rate on Reproductive Health Rate over a Twelve-Year Period in Islamshahr

Introduction: In recent years, population growth, birth rate promotion and reproductive health policies have been the main approach of population control programs. In this study, the researcher was going to investigate and got a close look to this important issue in the city of Islamshahr. The comparative study of prophylactic methods and their prevalence was conducted among fertile women in 2004 and 2016 to examine how their approach change following the changes in national policy has affected on reproductive health.Materials and Methods: Two thousand reproductive-age women who reside in Islamshahr voluntarily and confidential participated using a questionnaire. All data were analyzed using SPSS software.Results: The findings indicated that despite the decrease in contraceptive use in 2016 compared to 2004 (from 90.8% to 42%), the level of public awareness has been increased about their benefits and reproductive health So that we observed an increased awareness of sexually transmitted diseases and ways to fight them (from 27% to 56%). A decline in illegal abortion rate (from 60% to 22%) and an increase in the knowledge of appropriate lactation methods (from 25.8% to 40%) observed during the study period. Natural methods had the highest prevalence among contraceptive methods at both times of the survey. The knowledge of women about the proper methods for early marriage (from 25.3 to 11%) and emergencies showed a decrease (from 12.2% to 5.6%)

Studies of aerosol particle formation from various sources using ion and electron beam analytical techniques

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Laboratory and field test of a sampling method for characterization of combustion aerosols at high temperatures

The objective of this study was to design and experimentally examine a sampling method for high-temperature aerosols from biomass combustion, in which nucleation and condensation from fly ash forming vapors is controlled. The sampling method includes a high-temperature probe in which the hot gas is diluted and then cooled. Laboratory results from sampling a model aerosol with known concentrations of SiO2 particles and KCl vapor showed that when using a high dilution ratio, the KCl vapor was effectively separated from the aerosol by deposition onto the probe walls. When a lower dilution ratio was used, the KCl vapor generated a distinct nucleation mode when cooled in the probe. The sampling method was also used for sampling flue gas from a circulating fluidized bed boiler fired with forest residues. The results suggest that the major fractions of Ca, K, S, and Zn were present as particles at 780degreesC, whereas most of the Cl and Pb were present as gases. The field results are consistent with results previously reported and indicate that the method can be used for efficient and precise characterization of high-temperature combustion aerosols containing inorganic vapors

Traffic-generated emissions of ultrafine particles from pavement-tire interface

In a road simulator study, a significant source of sub-micrometer fine particles produced by the road-tire interface was observed. Since the particle size distribution and source strength is dependent on the type of tire used, it is likely that these particles largely originate from the tires, and not the road pavement. The particles consisted most likely of mineral oils from the softening filler and fragments of the carbon-reinforcing filler material (soot agglomerates). This identification was based on transmission electron microscopy studies of collected ultrafine wear particles and on-line thermal treatment using a thermodesorber. The mean particle number diameters were between 15-50 nm, similar to those found in light duty vehicle (LDV) tail-pipe exhaust. A simple box model approach was used to estimate emission factors in the size interval 15-700 nm. The emission factors increased with increasing vehicle speed, and varied between 3.7 x 10(11) and 3.2 x 10(12) particles vehicle(-1) km(-1) at speeds of 50 and 70 km h(-1). This corresponds to between 0.1-1% of tail-pipe emissions in real-world emission studies at similar speeds from a fleet of LDV with 95% gasoline and 5% diesel-fueled cars. The emission factors for particles originating from the road-tire interface were, however, similar in magnitude to particle number emission factors from liquefied petroleum gas-powered vehicles derived in test bench studies in Australia 2005. Thus the road-tire interface may be a significant contributor to particle emissions from ultraclean vehicles. (c) 2005 Elsevier Ltd. All rights reserved

Particle emissions from district heating units operating on three commonly used biofuels

The aim of this study was to characterise particle emissions from district heating units operating on three commonly used biofuels: forest residues, pellets and sawdust. Boilers used in the three district heating units were of moving grate type, with the maximum thermal output between 1 and 1.5 MW. The measurements were done after multicyclones, the only particle removal devices installed, therefore the direct emissions to ambient air were characterised. Number and mass size distributions were determined. Elemental composition of the particles, was determined by particle induced X-ray emissions analysis (PIXE) and thermal-optical analysis. Particles' morphology was assessed on the basis of transmission electron microscopy (TEM). Total number concentration of emitted particles with aerodynamic diameter smaller than 5 pm (PM5) at medium operation load ranged from 6.3 to 7.7 x 10(7) particles/cm(n)(3), with the slightly higher values from combustion of forest residues. PM5 mass concentration at medium load from low pressure impactor measurements ranged between 51 and 120 mg./m(n)(3), with the highest values from unit operating on forest residues. Both PM5 mass and total number concentrations were dominated by fine mode contributions i.e. particles with aerodynamic diameter smaller than 1 mum (PM1). Elements determined by PIXE (Z > 12) contributed to 21-34% of PM1 mass, of which K, S, Cl and Ca contributed to 18-33% of PM1 mass, and Zn, Mn, Fe, Cr, Pb and Cd to 1-3%. Emitted concentrations of heavy metals depended on type of the fuel and operating load. Particulate organic (OC) and elemental (EC) carbon contribution to PM1 ranged from 1-19% and 0-56%. respectively. Particulate OC concentrations strongly depended on the operation load regardless the type of the fuel, while EC concentrations seemed to depend both on load and the type of the fuel. Considering the potential public health implications of the obtained results, further research is needed to carefully assess the impact of particle emissions from biofuels combustion on human health and environment