Development and optimization of methodologies for the measurement of aerosol physical properties from mainstream heated tobacco aerosol

In this paper I discuss the influence of electron correlation effects in solids of current interest in solid state physics and chemistry and some experimental techniques which have been used to determine the magnitude of the electron-electron interactions. Of course the things we are really interested in solids are their physical properties such as the electrical, magnetic, thermal etc. properties and the effects of electron correlation on these. The measurement of these properties in themselves seldom contain enough detailed information to draw conclusions as to the origin of a discrepancy with conventional one particle like theory. For example we want to know why La2CuO4 is an antiferromagnetic insulator with a 2 eV band gap. The measurements of physical properties are usually macroscopic in character and in many cases boil down to the determination of a few quantities like the linear temperature coefficient of the specific heat or the power law dependence of the electrical conductivity at low temperatures or the temperature dependence of the specific heat, or the temperature dependence of the magnetic susceptibility.

Increasing efforts have been spent in the past two decades on field measurement of soil physical properties and on the development of transport models. Here a summary is given of the characteristics of field soils gleaned from such measurements. The principle feature of field soils is their variability over many length and time scales. Issues involved in measurements in a heterogeneous environment are considered. These include the interaction of measurement scale with perceived variability, soil-imposed weighting of measurements, the Heisenberg uncertainty principle, the use of correlations, inverse measurement techniques, and soil macrostructure and biological activity. Some criteria for field measurements are identified. Predictive frameworks for interpreting and using field data are discussed. These range from the fully deterministic to stochastic theories. The successes and limitations of these are considered. Finally, some remaining problem areas are identified.

Solute transport and dispersion.- Solute transport and dispersion - Commentary.- Quasianalytic and analytic approaches to unsaturated flow.- Quasianalytic and analytic approaches to unsaturated flow - Commentary.- Measurement of soil physical properties in the field.- Measurement of soil physical properties in the field - Commentary.- Canopy transport processes.- Canopy transport processes - Commentary.- Surface temperature and the surface energy balance.- Surface temperature and the surface energy balance - Commentary.- Stomatal physiology and gas exchange in the field.- Stomatal physiology and gas exchange in the field - Commentary.- Air flow over complex terrain.- Air flow over complex terrain - Commentary.- Convective processes in the lower atmosphere.- Convective processes in the lower atmosphere - Commentary.- Turbulent wakes in the atmospheric boundary layer.- Turbulent wakes in the atmospheric boundary layer - Commentary.- Particulate transport in the atmosphere: wind erosion.- Processes of water erosion.- One-dimensional solid-liquid separation.- One-dimensional solid-liquid separation - Commentary.- Atmospheric dispersion - Observations and Models.- Atmospheric dispersion - Observations and Models - Commentary.

Long-term measurements of aerosol optical and physical properties over the Eastern Mediterranean: Hygroscopic nature and source regions

Measurements of aerosol optical and physical properties, and chemical composition were conducted at Toulouse, an urban site of southwest France, as part of the CAPITOUL experiment. A period of intensive observations was held over 10 days during the summer campaign in June–July, 2004. During this period, PM2.5 concentrations ranged between 1 and 50 µg m−3. Aerosol size distributions exhibit the presence of three distinct modes which could be fitted by lognormal functions. Diurnal variations of aerosol concentration, size distribution, BC concentration, scattering and absorption coefficients, and single scattering albedo show the presence of two maxima corresponding to rush hours due to various urban activities such as vehicle traffic. Over the period of study, the single scattering albedo at 0.52 µm is found to be 0.7 ± 0.1, indicating the dominance of absorbing aerosols over Toulouse. Airborne measurements observed the vertical distribution of aerosols in the atmosphere. These observations clearly show that aerosol is mostly contained within the UBL which contributes significantly to the aerosol optical depth. The GAME radiative transfer model (RTM) has been used to carry out the radiative transfer computations. A synergetic approach was applied to generate spectral values of aerosol parameters required as input for the radiative transfer calculations. Vertical radio soundings and airborne measurements provided in-situ parameters required for the RTM. Simulations indicate that aerosols over Toulouse reduce significantly (−30 W m−2) the solar energy reaching the surface, mainly by absorption of the solar radiation into the atmosphere. At the TOA, aerosol forcing is even found to be positive (+0.8 W m−2). These results confirm that local direct aerosol forcing in urban atmosphere is mainly driven by the absorbing black carbon aerosols. The mean heating rate within the UBL is considerably enhanced, by 4.57 K day−1, due to the presence of absorbing aerosols.

We present results from complimentary measurements of physical and optical properties of aerosols carried out at Delhi, as part of the Indian Space Research Organization Geosphere Biosphere Programme's Land Campaign II in December 2004. For the first time we unravel ground truth values of several radiatively important aerosol parameters such as their wavelength dependency in absorption, scattering behavior, single‐scattering albedo, number size distribution, and vertical distribution in the atmosphere from this polluted megacity in south Asia. Interesting features are observed in the behavior of aerosol parameters under intermittent foggy, hazy, and clear‐sky conditions prevalent during the campaign. All aerosol parameters exhibited a large distribution in their values, with variabilities being particularly higher on hazy and foggy days. The average clear‐sky aerosol optical depth (AOD) value is 0.91 ± 0.48, which is higher than the AOD value reported for most other cities in India during this season of the year. Increases in AOD on hazy and foggy days are found to be spectrally nonuniform. The percentage increase in AOD at shorter wavelengths was higher on hazy days compared to clear days. Diurnally averaged BC mass concentration varied from a low of 15 μg/m3 during clear days to a high of about 65 μg/m3 on hazy days. The wavelength dependency of aerosol absorption shows signatures of the presence of a significant amount of absorbing aerosols produced from biofuel/biomass burning. Single‐scattering albedo at 525 nm is found to vary between 0.6 and 0.8 with an average value of 0.68 for the entire period. Lidar observations reveal that during a fog event there is a subsidence of aerosols to an extremely dense and shallow atmospheric layer of less than 200 m height from the surface. The presence of an aerosol layer at elevated altitudes is also detected. All the results are combined and used for estimating aerosol radiative forcing using a discrete ordinate radiative transfer model. We find a large negative forcing at the surface level in the range of −40 to −86 W/m2, while forcing at the top of the atmosphere varied between −2 and +3 W/m2.

Micro-nano robotics has recently become an important robotics field, especially technologies to measure and control phenomena related to cells and tissues. Based on this background, analysis of cell characteristics is a hot topic in micro-nano robotics. However, current analytical methods have issues with efficiency because cell manipulation and measurements must be separately performed for each cell. If cell manipulation and mechanical property measurements could be simultaneously conducted, then the efficiency would be greatly improved. Herein physical property measurements and cellular diagnosis were examined using a two-fingered microhand system with a micro force sensor and an algorithm from the nano indentation approach. Additionally, we conducted several experiments to demonstrate the applicability of this method.

Polymer concrete: A potential construction material for desalination plants. Part I

One of the important results of the Japan Sea drilling by ODP is the detection of an opal-A/opal-CT transformation at all the drill sites. The transformation boundary is well recognized in physical property and downhole measurements as well as in lithologic descriptions. Because the boundary shows a marked change of density, the boundary appears in seismic reflection profiles as a BSR. The transformation of opal-A to opal-CT is closely correlated with temperature and age of host rock in the Japan Sea. We estimate and evaluate Japan Sea heat flow by using the opal-A/opal-CT bottom simulating reflector (BSR) observed in seismic reflection profiles. Then we estimated the age of host rock from available seismic profiles based on the assumption of constant sedimentation rate. Therefore, the temperatures at opal-A/opal-CT boundary were estimated from seismic profiles. The temperature data were converted to surface heat flow data by using the thermal conductivity data obtained by shipboard physical property measurements. The estimated BSR heat flow showed significant agreement with individual probe heat flow data. We confirmed the validity of BSR heat flow on a multichannel seismic profile. This method can provide large areal estimates of the surface heat flow. The opal-A/opal-CT BSR can contribute to defining the thermal structure of the Yamato Basin, Japan Sea.

    Secondary organic aerosols (SOAs) account for a large fraction of atmospheric aerosol mass and play significant roles in visibility impairment by scattering solar radiation. However, comprehensive evaluations of SOA scattering abilities under ambient relative humidity (RH) conditions on the basis of field measurements are still lacking due to the difficulty of simultaneously direct quantifications of SOA scattering efficiency in dry state and SOA water uptake abilities. In this study, field measurements of aerosol chemical and physical properties were conducted in winter in Guangzhou using a humidified nephelometer system and aerosol chemical speciation monitor. A modified multilinear regression model was proposed to retrieve dry-state mass scattering efficiencies (MSE, defined as scattering coefficient per unit aerosol mass) of aerosol components. The more oxidized oxygenated organic aerosol (MOOA) with O/C ratio of 1.17 was identified as the most efficient light scattering aerosol component. On average, 34% mass contribution of MOOA to total submicron organic aerosol mass contributed 51% of dry-state organic aerosol scattering. The overall organic aerosol hygroscopicity parameter κOA was quantified directly through hygroscopicity closure, and hygroscopicity parameters of SOA components were further retrieved using multilinear regression model by assuming hydrophobic properties of primary organic aerosols. The highest water uptake ability of MOOA among organic aerosol factors was revealed with κMOOA reaching 0.23, thus further enhancing the fractional contribution of MOOA in ambient organic aerosol scattering. In particular, the scattering abilities of MOOA was found to be even higher than those of ammonium nitrate under RH of

Abstract. The notable increase in biofuel usage by the road transportation sector in Brazil during recent years has significantly altered the vehicular fuel composition. Consequently, many uncertainties are currently found in particulate matter vehicular emission profiles. In an effort to better characterise the emitted particulate matter, measurements of aerosol physical and chemical properties were undertaken inside two tunnels located in the São Paulo Metropolitan Area (SPMA). The tunnels show very distinct fleet profiles: in the Jânio Quadros (JQ) tunnel, the vast majority of the circulating fleet are light duty vehicles (LDVs), fuelled on average with the same amount of ethanol as gasoline. In the Rodoanel (RA) tunnel, the particulate emission is dominated by heavy duty vehicles (HDVs) fuelled with diesel (5% biodiesel). In the JQ tunnel, PM2.5 concentration was on average 52 μg m−3, with the largest contribution of organic mass (OM, 42%), followed by elemental carbon (EC, 17%) and crustal elements (13%). Sulphate accounted for 7% of PM2.5 and the sum of other trace elements was 10%. In the RA tunnel, PM2.5 was on average 233 μg m−3, mostly composed of EC (52%) and OM (39%). Sulphate, crustal and the trace elements showed a minor contribution with 5%, 1%, and 1%, respectively. The average OC : EC ratio in the JQ tunnel was 1.59 ± 0.09, indicating an important contribution of EC despite the high ethanol fraction in the fuel composition. In the RA tunnel, the OC : EC ratio was 0.49 ± 0.12, consistent with previous measurements of diesel-fuelled HDVs. Besides bulk carbonaceous aerosol measurement, polycyclic aromatic hydrocarbons (PAHs) were quantified. The sum of the PAHs concentration was 56 ± 5 ng m−3 and 45 ± 9 ng m−3 in the RA and JQ tunnel, respectively. In the JQ tunnel, benzo(a)pyrene (BaP) ranged from 0.9 to 6.7 ng m−3 (0.02–0.1‰ of PM2.5) whereas in the RA tunnel BaP ranged from 0.9 to 4.9 ng m−3 (0.004–0. 02‰ of PM2.5), indicating an important relative contribution of LDVs emission to atmospheric BaP. Real-time measurements performed in both tunnels provided aerosol size distributions and optical properties. The average particle count yielded 73 000 cm−3 in the JQ tunnel and 366 000 cm−3 in the RA tunnel, with an average diameter of 48 nm in the former and 39 nm in the latter. Aerosol single scattering albedo, calculated from scattering and absorption observations in the JQ tunnel, indicates a value of 0.5 associated with LDVs. Such single scattering albedo is 20–50% higher than observed in previous tunnel studies, possibly as a result of the large biofuel usage. Given the exceedingly high equivalent black carbon loadings in the RA tunnel, real time light absorption measurements were possible only in the JQ tunnel. Nevertheless, using EC measured from the filters, a single scattering albedo of 0.31 for the RA tunnel has been estimated. The results presented here characterise particulate matter emitted from nearly 1 million vehicles fuelled with a considerable amount of biofuel, providing a unique experimental site worldwide.

Characteristics of the transport and vertical structure of aerosols during ABC-EAREX2005

A closure study of aerosol optical properties at a regional background mountainous site in Eastern China

Abstract. Currently many ground-based atmospheric stations include in-situ measurements of aerosol physical and optical properties, resulting in more than 20 long-term (> 10 yr) aerosol measurement sites in the Northern Hemisphere and Antarctica. Most of these sites are located at remote locations and monitor the aerosol particle number concentration, wavelength-dependent light scattering, backscattering, and absorption coefficients. The existence of these multi-year datasets enables the analysis of long-term trends of these aerosol parameters, and of the derived light scattering Ångström exponent and backscatter fraction. Since the aerosol variables are not normally distributed, three different methods (the seasonal Mann-Kendall test associated with the Sen's slope, the generalized least squares fit associated with an autoregressive bootstrap algorithm for confidence intervals, and the least-mean square fit applied to logarithms of the data) were applied to detect the long-term trends and their magnitudes. To allow a comparison among measurement sites, trends on the most recent 10 and 15 yr periods were calculated. No significant trends were found for the three continental European sites. Statistically significant trends were found for the two European marine sites but the signs of the trends varied with aerosol property and location. Statistically significant decreasing trends for both scattering and absorption coefficients (mean slope of −2.0% yr−1) were found for most North American stations, although positive trends were found for a few desert and high-altitude sites. The difference in the timing of emission reduction policy for the Europe and US continents is a likely explanation for the decreasing trends in aerosol optical parameters found for most American sites compared to the lack of trends observed in Europe. No significant trends in scattering coefficient were found for the Arctic or Antarctic stations, whereas the Arctic station had a negative trend in absorption coefficient. The high altitude Pacific island station of Mauna Loa presents positive trends for both scattering and absorption coefficients.

Despite the substantial improvements in the measurements of aerosol physical and chemical properties and in the direct and indirect radiative effects of aerosols, there is still a need for studying the properties of aerosols under controlled laboratory conditions to develop a mechanistic and quantitative understanding of aerosol formation, chemistry, and dynamics. In this work, we present the factors that affect measurement accuracy and the resulting uncertainties of the extinction-minus-scattering method using a combination of cavity ring-down spectroscopy (CRDS) and integrating nephelometry at a wider range of optical wavelengths than previously attempted. Purely scattering polystyrene latex (PSL) spheres with diameters from 107–303 nm and absorbing polystyrene spheres (APSL) with 390 nm diameter were used to determine the consistency and agreement, within experimental uncertainties, of CRDS and nephelometer values with theoretical calculations derived from Mie theory for non-absorbing spheres. Overall uncertainties for extinction cross-section were largely 10%–11% and dominated by condensation particle counter (CPC) measurement error. Two methods for determining σext error are described, and they were found to produce equivalent results. Systematic uncertainties due to particle losses, RD cell geometry (RL), CPC counting efficiency, ring-down regression fitting, blank drift, optical tweezing, and recapturing of forward scattered light are also investigated. The random error observed in this work for absorbing spheres is comparable to previous reported measurements. For both absorbing and non-absorbing spheres, a statistical framework is developed for including the contributions to random error due to CPC measurement uncertainty, RL, statistical fluctuations in particle counts, fluctuations in the blank, and mass flow controller flow error.Copyright 2014 American Association for Aerosol Research