Real-Time Monitoring of Viable Bioaerosols: Capability of the UVAPS to Predict the Amount of Individual Microorganisms in Aerosol Particles

The Ultraviolet Aerodynamic Particle Sizer (UVAPS) is a novel aerosol monitor for enumerating and sizing microbial aerosols. To explore the capability of the method to estimate the number of microorganisms (bacteria) in aerosol particles, and thus to provide information on the concentration of airborne microorganisms, in addition to the total number of microbe carrying particles, a linearity of the UVAPS fluorescent signals with respect to the concentration of the fluorophores was investigated. As the amount of intrinsic fluorophores in bacteria may vary depending on viability status of the cells, the linearity was initially investigated for the non-microbial aerosols (NADH, NADPH, or riboflavin), with preset concentrations of fluorescent material in aerosol particles. The succeeding tests were performed with bacterial aerosols containing carefully washed Bacillus subtilis or Micrococcus luteus vegetative cells. To correlate the fluorescence intensity with particle size, which determines the amount of fluorophores (or cells) in the aerosol particles, the UVAPS data were analysed for each of 64 size-channels individually. The fluorescence intensity was linear with respect to the particle volume at the fluorophore concentrations characteristic to bacterial cells (correlation factors were typically greater than 0.9) and became curvilinear at higher concentrations. As the linearity of the UVAPS signals was confirmed for bacterial aerosols, it was concluded that the UVAPS can be used to estimate the concentration of airborne viable bacterial cells in artificially generated bioaerosols. The predicted concentrations of viable cells in the M. luteus aerosols compared favourably with the results of the AGI-30 sampling for culturable cells

Carbon dioxide emissions from diesel and compressed natural gas buses during acceleration

Motor vehicle emission factors are generally derived from driving tests mimicking steady state conditions or transient drive cycles. However, neither of these test conditions completely represents real world driving conditions. In particular, they fail to determine emissions generated during the accelerating phase – a condition in which urban buses spend much of their time. In this study we analyse and compare the results of time-dependant emission measurements conducted on diesel and compressed natural gas (CNG) buses during an urban driving cycle on a chassis dynamometer and we derive power-law expressions relating carbon dioxide (CO2) emission factors to the instantaneous speed while accelerating from rest. Emissions during acceleration are compared with that during steady speed operation. These results have important implications for emission modelling particularly under congested traffic conditions

The value postulates and the transformation of transition societies in South East Europe

The European idea of uniting the countries of the European continent is the impetus for attracting and transformation of post communist societies. The process of harmonization of legislation is a systematic attempt at regulation of relations in society through the establishment of valuable principles and adoption of established standards in the management of states and economies. The dilemma is whether it is possible a sustainable development transformation by simply copying the institutional and legal system solutions from Europe, without involving moral value body of principles and standards in ruling the states? The purpose of the paper is to offer a reasoned response on ways how this collision to be resolved, whether the transition can be performed only in a systematic manner, institutionally and legally, or must go in parallel with social intervention in the cultural set and moral value corpus based on verified and approved ethical values, principles and standards

Relation Between Particle Mass and Number for Submicrometer Airborne Particles

The relationship between particle mass and the number of ambient air particles for the submicrometer size range was examined using a Tapered Element Oscillating Microbalance to determine the mass concentration, and a Scanning Mobility Particle Sizer to determine the volume concentration and total number of particles. After validating the techniques through their application to the estimation of submicrometer particle density for two laboratory generated aerosols of known bulk density (Sodium Chloride and Di-2-ethylhexyl-sebacate), the submicrometer fraction of laboratory generated Environmental Tobacco Smoke and ambient air were examined and an estimate of the average submicrometer particle densities for these aerosols found to be 1.18 g cm-3 and 1.7 g cm-3 respectively

Commercial Banking and Interbank Insurance: The Diamond-Dybvig Model Revisited

The goal of this paper is to investigate the possibility of incorporating interbank insurance among commercial banks. This is done by building upon the Diamond-Dybvig model. We extend the Diamond-Dybvig model in three ways. First we abandon the single intermediary environment by introducing a banking sector that is made up of a continuum of banks of mass 1; we assume that a small proportion (exogenously given) of banks experience runs. Next, we suppose that all banks have access to and invest in interbank insurance. Lastly, it is assumed that when banks withdraw illiquid funds prematurely they must pay a mandatory transaction cost. In a banking system with liquidity shocks we show that, by designing an optimal interbank insurance contract, the possibility of a bank becoming illiquid during a bank run is zero

Characterization of iodine particles with Volatilization-Humidification Tandem Differential Mobility Analyser (VH-TDMA), Raman and SEM techniques

Particles formed upon photo-oxidation of CH2I2 and particles of I2O5 and HIO3 have been studied using a Volatilisation and Humidification Tandem Differential Mobility Analyser (VH-TDMA) system. Volatilization and hygroscopic behaviour have been investigated as function of temperature (from 25 to 400 degrees Celsius), humidity (RH from 80 to 98%), initial aerosol sizes (from 27 to 100 nm mobility diameter) and in nitrogen or air as the sheath gasses. The volatility behaviour of particles formed upon photo-oxidation of CH2I2 is more similar to that of HIO3 particles in a filtered sheath air than in nitrogen, with the particle shrinkage occurring at 190 degrees Celsius and accompanied by hygroscopic growth. Despite its high solubility, HIO3 was found not to be hygroscopic at room temperature with no significant growth displayed until the thermodenuder temperature reached 200 degrees Celsius or above when the particles have transformed into I2O5. Diiodopentaoxide (I2O5) particles exhibit relatively low hygroscopic growth factors of 1.2-2 in the humidity range investigated. Scanning Electron Microscopy (SEM) of particles formed upon photo-oxidation of CH2I2 shows that their primary elemental components were iodine and oxygen in a stoichiometric ratio of approximately 1:2 with 10% error. Both Raman spectra and SEM show poor crystallinity for all the aerosols produced

Pleading Patterns and the Role of Litigation as a Driver of Federal Climate Change Legislation

Based on a variant of the Elliott-Ackerman-Millian theory that variable, potentially inconsistent and costly litigation outcomes induce industry to seek federal preemptive legislation to reign in such costs, we collect data on climate change-related litigation to determine whether litigation might motivate major greenhouse gas emitters to accept a preemptive, though possibly carbon-restricting, legislative compromise. We conduct a spectral cluster analysis on 178 initial federal and state judicial filings to reveal the most relevant groupings among climate change-related suits and their underlying pleading patterns. Besides exposing the general content and structure of climate change-related filings, this study identifies major specific pleading trends, such as the low frequency of tort claim pleading and the high level of segregation of state and federal causes of action. These data also allow investigating how generally applicable litigation doctrines have influenced pleading patterns, even subduing the impact of the two major U.S. Supreme Court rulings in this area. These findings lead us to conclude that this type of litigation has not induced and is not likely to induce major emitters to embrace preemptive emissions legislation as a risk-reducing compromise

Effect of pulsed power on particle matter in diesel engine exhaust using a DBD plasma reactor

Nonthermal plasma (NTP) treatment of exhaust gas is a promising technology for both nitrogen oxides (NOX) and particulate matter (PM) reduction by introducing plasma into the exhaust gases. This paper considers the effect of NTP on PM mass reduction, PM size distribution, and PM removal efficiency. The experiments are performed on real exhaust gases from a diesel engine. The NTP is generated by applying high-voltage pulses using a pulsed power supply across a dielectric barrier discharge (DBD) reactor. The effects of the applied high-voltage pulses up to 19.44 kVpp with repetition rate of 10 kHz are investigated. In this paper, it is shown that the PM removal and PM size distribution need to be considered both together, as it is possible to achieve high PM removal efficiency with undesirable increase in the number of small particles. Regarding these two important factors, in this paper, 17 kVpp voltage level is determined to be an optimum point for the given configuration. Moreover, particles deposition on the surface of the DBD reactor is found to be a significant phenomenon, which should be considered in all plasma PM removal tests