Nanotip analysis for dielectrophoretic concentration of nanosized viral particles

International Nuclear Information System (INIS)

Yeo, Woon-Hong; Lee, Hyun-Boo; Kim, Jong-Hoon; Chung, Jae-Hyun; Lee, Kyong-Hoon

2013-01-01

Rapid and sensitive detection of low-abundance viral particles is strongly demanded in health care, environmental control, military defense, and homeland security. Current detection methods, however, lack either assay speed or sensitivity, mainly due to the nanosized viral particles. In this paper, we compare a dendritic, multi-terminal nanotip (‘dendritic nanotip’) with a single terminal nanotip (‘single nanotip’) for dielectrophoretic (DEP) concentration of viral particles. The numerical computation studies the concentration efficiency of viral particles ranging from 25 to 100 nm in radius for both nanotips. With DEP and Brownian motion considered, when the particle radius decreases by two times, the concentration time for both nanotips increases by 4–5 times. In the computational study, a dendritic nanotip shows about 1.5 times faster concentration than a single nanotip for the viral particles because the dendritic structure increases the DEP-effective area to overcome the Brownian motion. For the qualitative support of the numerical results, the comparison experiment of a dendritic nanotip and a single nanotip is conducted. Under 1 min of concentration time, a dendritic nanotip shows a higher sensitivity than a single nanotip. When the concentration time is 5 min, the sensitivity of a dendritic nanotip for T7 phage is 10 4 particles ml −1 . The dendritic nanotip-based concentrator has the potential for rapid identification of viral particles. (paper)

Numerical investigation of the effect of particle concentration on particle measurement by digital holography

Science.gov (United States)

Zhao, Huafeng; Zhou, Binwu; Wu, Xuecheng; Wu, Yingchun; Gao, Xiang; Gréhan, Gérard; Cen, Kefa

2014-04-01

Digital holography plays a key role in particle field measurement, and appears to be a strong contender as the next-generation technology for diagnostics of 3D particle field. However, various recording parameters, such as the recording distance, the particle size, the wavelength, the size of the CCD chip, the pixel size and the particle concentration, will affect the results of the reconstruction, and may even determine the success or failure of a measurement. This paper presents a numerical investigation on the effect of particle concentration, the volume depth to evaluate the capability of digital holographic microscopy. Standard particles holograms with all known recording parameters are numerically generated by using a common procedure based on Lorenz-Mie scattering theory. Reconstruction of those holograms are then performed by a wavelet-transform based method. Results show that the reconstruction efficiency decreases quickly until particle concentration reaches 50×104 (mm-3), and decreases linearly with the increase of particle concentration from 50 × 104 (mm-3) to 860 × 104 (mm-3) in the same volume. The first half of the line waves larger than the second half. It also indicates that the increase of concentration leads the rise in average diameter error and z position error of particles. Besides, the volume depth also plays a key role in reconstruction.

How comparable are size-resolved particle number concentrations from different instruments?

Science.gov (United States)

Hornsby, K. E.; Pryor, S. C.

2012-12-01

The need for comparability of particle size resolved measurements originates from multiple drivers including: (i) Recent suggestions that air quality standards for particulate matter should migrate from being mass-based to incorporating number concentrations. This move would necessarily be predicated on measurement comparability which is absolutely critical to compliance determination. (ii) The need to quantify and diagnose causes of variability in nucleation and growth rates in nano-particle experiments conducted in different locations. (iii) Epidemiological research designed to identify key parameters in human health responses to fine particle exposure. Here we present results from a detailed controlled laboratory instrument inter-comparison experiment designed to investigate data comparability in the size range of 2.01-523.3 nm across a range of particle composition, modal diameter and absolute concentration. Particle size distributions were generated using a TSI model 3940 Aerosol Generation System (AGS) diluted using zero air, and sampled using four TSI Scanning Mobility Particle Spectrometer (SMPS) configurations and a TSI model 3091 Fast Mobility Particle Sizer (FMPS). The SMPS configurations used two Electrostatic Classifiers (EC) (model 3080) attached to either a Long DMA (LDMA) (model 3081) or a Nano DMA (NDMA) (model 3085) plumbed to either a TSI model 3025A Butanol Condensed Particle Counting (CPC) or a TSI model 3788 Water CPC. All four systems were run using both high and low flow conditions, and were operated with both the internal diffusion loss and multiple charge corrections turned on. The particle compositions tested were sodium chloride, ammonium nitrate and olive oil diluted in ethanol. Particles of all three were generated at three peak concentration levels (spanning the range observed at our experimental site), and three modal particle diameters. Experimental conditions were maintained for a period of 20 minutes to ensure experimental

Primary standard for the number concentration of liquid-borne particles in the 10 to 20 µm diameter range

International Nuclear Information System (INIS)

Sakaguchi, T; Ehara, K

2011-01-01

The national primary standard for the number concentration of liquid-borne particles in the 10 to 20 µm diameter range has been developed at the National Institute of Advanced Industrial Science and Technology (AIST), Japan. The standard consists of a total number counting type flow cytometer (T-FCM) and an electronic balance. The T-FCM is a commercial flow cytometer modified so that the total number of particles in an aqueous suspension sampled in a test tube can be counted, and the electronic balance is used to determine the mass of the suspension. This standard is intended to be used for calibrating commercial standard suspensions of monodisperse polystyrene latex (PSL) particles. The measurand in the calibration is the mass-based number concentration (the particle number in a unit mass of a suspension), and the calibration capability covers the concentration range from 5 × 10 2 to 2 × 10 6 particles g −1 . When the concentration of the suspension is higher than 2 × 10 3 particles g −1 , the suspension is first diluted to about 1 × 10 3 particles g −1 to suppress the coincidence loss in particle counting by the T-FCM. The validity of the calibration with the T-FCM was examined by comparison with an independent method in which a scanning electron microscope (SEM) was used to determine the number concentration of particles deposited on a silicon wafer. For a suspension of 10 µm PSL particles with a concentration of approximately 1 × 10 6 particles g −1 , the concentration values determined by the T-FCM and SEM methods were 1.042 × 10 6 and 1.035 × 10 6 particles g −1 , respectively: The difference was less than 0.7%. The relative expanded uncertainty of the measurement by the T-FCM method with the coverage factor k = 2 was 4.4%

Concentrations and Sources of Airborne Particles in a Neonatal Intensive Care Unit

Science.gov (United States)

Licina, Dusan; Bhangar, Seema; Brooks, Brandon; Baker, Robyn; Firek, Brian; Tang, Xiaochen; Morowitz, Michael J.; Banfield, Jillian F.; Nazaroff, William W.

2016-01-01

Premature infants in neonatal intensive care units (NICUs) have underdeveloped immune systems, making them susceptible to adverse health consequences from air pollutant exposure. Little is known about the sources of indoor airborne particles that contribute to the exposure of premature infants in the NICU environment. In this study, we monitored the spatial and temporal variations of airborne particulate matter concentrations along with other indoor environmental parameters and human occupancy. The experiments were conducted over one year in a private-style NICU. The NICU was served by a central heating, ventilation and air-conditioning (HVAC) system equipped with an economizer and a high-efficiency particle filtration system. The following parameters were measured continuously during weekdays with 1-min resolution: particles larger than 0.3 μm resolved into 6 size groups, CO2 level, dry-bulb temperature and relative humidity, and presence or absence of occupants. Altogether, over sixteen periods of a few weeks each, measurements were conducted in rooms occupied with premature infants. In parallel, a second monitoring station was operated in a nearby hallway or at the local nurses’ station. The monitoring data suggest a strong link between indoor particle concentrations and human occupancy. Detected particle peaks from occupancy were clearly discernible among larger particles and imperceptible for submicron (0.3–1 μm) particles. The mean indoor particle mass concentrations averaged across the size range 0.3–10 μm during occupied periods was 1.9 μg/m3, approximately 2.5 times the concentration during unoccupied periods (0.8 μg/m3). Contributions of within-room emissions to total PM10 mass in the baby rooms averaged 37–81%. Near-room indoor emissions and outdoor sources contributed 18–59% and 1–5%, respectively. Airborne particle levels in the size range 1–10 μm showed strong dependence on human activities, indicating the importance of indoor

Concentrations and Sources of Airborne Particles in a Neonatal Intensive Care Unit.

Directory of Open Access Journals (Sweden)

Dusan Licina

Full Text Available Premature infants in neonatal intensive care units (NICUs have underdeveloped immune systems, making them susceptible to adverse health consequences from air pollutant exposure. Little is known about the sources of indoor airborne particles that contribute to the exposure of premature infants in the NICU environment. In this study, we monitored the spatial and temporal variations of airborne particulate matter concentrations along with other indoor environmental parameters and human occupancy. The experiments were conducted over one year in a private-style NICU. The NICU was served by a central heating, ventilation and air-conditioning (HVAC system equipped with an economizer and a high-efficiency particle filtration system. The following parameters were measured continuously during weekdays with 1-min resolution: particles larger than 0.3 μm resolved into 6 size groups, CO2 level, dry-bulb temperature and relative humidity, and presence or absence of occupants. Altogether, over sixteen periods of a few weeks each, measurements were conducted in rooms occupied with premature infants. In parallel, a second monitoring station was operated in a nearby hallway or at the local nurses' station. The monitoring data suggest a strong link between indoor particle concentrations and human occupancy. Detected particle peaks from occupancy were clearly discernible among larger particles and imperceptible for submicron (0.3-1 μm particles. The mean indoor particle mass concentrations averaged across the size range 0.3-10 μm during occupied periods was 1.9 μg/m3, approximately 2.5 times the concentration during unoccupied periods (0.8 μg/m3. Contributions of within-room emissions to total PM10 mass in the baby rooms averaged 37-81%. Near-room indoor emissions and outdoor sources contributed 18-59% and 1-5%, respectively. Airborne particle levels in the size range 1-10 μm showed strong dependence on human activities, indicating the importance of indoor

Explaining global surface aerosol number concentrations in terms of primary emissions and particle formation

Science.gov (United States)

Spracklen, D. V.; Carslaw, K. S.; Merikanto, J.; Mann, G. W.; Reddington, C. L.; Pickering, S.; Ogren, J. A.; Andrews, E.; Baltensperger, U.; Weingartner, E.; Boy, M.; Kulmala, M.; Laakso, L.; Lihavainen, H.; Kivekäs, N.; Komppula, M.; Mihalopoulos, N.; Kouvarakis, G.; Jennings, S. G.; O'Dowd, C.; Birmili, W.; Wiedensohler, A.; Weller, R.; Gras, J.; Laj, P.; Sellegri, K.; Bonn, B.; Krejci, R.; Laaksonen, A.; Hamed, A.; Minikin, A.; Harrison, R. M.; Talbot, R.; Sun, J.

2010-05-01

We synthesised observations of total particle number (CN) concentration from 36 sites around the world. We found that annual mean CN concentrations are typically 300-2000 cm-3 in the marine boundary layer and free troposphere (FT) and 1000-10 000 cm-3 in the continental boundary layer (BL). Many sites exhibit pronounced seasonality with summer time concentrations a factor of 2-10 greater than wintertime concentrations. We used these CN observations to evaluate primary and secondary sources of particle number in a global aerosol microphysics model. We found that emissions of primary particles can reasonably reproduce the spatial pattern of observed CN concentration (R2=0.46) but fail to explain the observed seasonal cycle (R2=0.1). The modeled CN concentration in the FT was biased low (normalised mean bias, NMB=-88%) unless a secondary source of particles was included, for example from binary homogeneous nucleation of sulfuric acid and water (NMB=-25%). Simulated CN concentrations in the continental BL were also biased low (NMB=-74%) unless the number emission of anthropogenic primary particles was increased or a mechanism that results in particle formation in the BL was included. We ran a number of simulations where we included an empirical BL nucleation mechanism either using the activation-type mechanism (nucleation rate, J, proportional to gas-phase sulfuric acid concentration to the power one) or kinetic-type mechanism (J proportional to sulfuric acid to the power two) with a range of nucleation coefficients. We found that the seasonal CN cycle observed at continental BL sites was better simulated by BL particle formation (R2=0.3) than by increasing the number emission from primary anthropogenic sources (R2=0.18). The nucleation constants that resulted in best overall match between model and observed CN concentrations were consistent with values derived in previous studies from detailed case studies at individual sites. In our model, kinetic and activation

Concentration and size distribution of particles in abstracted groundwater

NARCIS (Netherlands)

Van Beek, C.G.E.M.; de Zwart, A.H.; Balemans, M.; Kooiman, J.W.; van Rosmalen, C.; Timmer, H.; Vandersluys, J.; Stuijfzand, P.J.

2010-01-01

Particle number concentrations have been counted and particle size distributions calculated in groundwater derived by abstraction wells. Both concentration and size distribution are governed by the discharge rate: the higher this rate the higher the concentration and the higher the proportion of

Concentration, size, and density of total suspended particulates at the air exhaust of concentrated animal feeding operations.

Science.gov (United States)

Yang, Xufei; Lee, Jongmin; Zhang, Yuanhui; Wang, Xinlei; Yang, Liangcheng

2015-08-01

Total suspended particulate (TSP) samples were seasonally collected at the air exhaust of 15 commercial concentrated animal feeding operations (CAFOs; including swine finishing, swine farrowing, swine gestation, laying hen, and tom turkey) in the U.S. Midwest. The measured TSP concentrations ranged from 0.38 ± 0.04 mg m⁻³ (swine gestation in summer) to 10.9 ± 3.9 mg m⁻³ (tom turkey in winter) and were significantly affected by animal species, housing facility type, feeder type (dry or wet), and season. The average particle size of collected TSP samples in terms of mass median equivalent spherical diameter ranged from 14.8 ± 0.5 µm (swine finishing in winter) to 30.5 ± 2.0 µm (tom turkey in summer) and showed a significant seasonal effect. This finding affirmed that particulate matter (PM) released from CAFOs contains a significant portion of large particles. The measured particle size distribution (PSD) and the density of deposited particles (on average 1.65 ± 0.13 g cm⁻³) were used to estimate the mass fractions of PM10 and PM2.5 (PM ≤ 10 and ≤ 2.5 μm, respectively) in the collected TSP. The results showed that the PM10 fractions ranged from 12.7 ± 5.1% (tom turkey) to 21.1 ± 3.2% (swine finishing), whereas the PM2.5 fractions ranged from 3.4 ± 1.9% (tom turkey) to 5.7 ± 3.2% (swine finishing) and were smaller than 9.0% at all visited CAFOs. This study applied a filter-based method for PSD measurement and deposited particles as a surrogate to estimate the TSP's particle density. The limitations, along with the assumptions adopted during the calculation of PM mass fractions, must be recognized when comparing the findings to other studies.

Refractometric total protein concentrations in icteric serum from dogs.

Science.gov (United States)

Gupta, Aradhana; Stockham, Steven L

2014-01-01

To determine whether high serum bilirubin concentrations interfere with the measurement of serum total protein concentration by refractometry and to assess potential biases among refractometer measurements. Evaluation study. Sera from 2 healthy Greyhounds. Bilirubin was dissolved in 0.1M NaOH, and the resulting solution was mixed with sera from 2 dogs from which food had been withheld to achieve various bilirubin concentrations up to 40 mg/dL. Refractometric total protein concentrations were estimated with 3 clinical refractometers. A biochemical analyzer was used to measure biuret assay-based total protein and bilirubin concentrations with spectrophotometric assays. No interference with refractometric measurement of total protein concentrations was detected with bilirubin concentrations up to 41.5 mg/dL. Biases in refractometric total protein concentrations were detected and were related to the conversion of refractive index values to total protein concentrations. Hyperbilirubinemia did not interfere with the refractometric estimation of serum total protein concentration. The agreement among total protein concentrations estimated by 3 refractometers was dependent on the method of conversion of refractive index to total protein concentration and was independent of hyperbilirubinemia.

Particle interactions in concentrated suspensions

International Nuclear Information System (INIS)

Mondy, L.A.; Graham, A.L.; Abbott, J.R.; Brenner, H.

1993-01-01

An overview is presented of research that focuses on slow flows of suspensions in which colloidal and inertial effects are negligibly small. The authors describe nuclear magnetic resonance imaging experiments to quantitatively measure particle migration occurring in concentrated suspensions undergoing a flow with a nonuniform shear rate. These experiments address the issue of how the flow field affects the microstructure of suspensions. In order to understand the local viscosity in a suspension with such a flow-induced, spatially varying concentration, one must know how the viscosity of a homogeneous suspension depends on such variables as solids concentration and particle orientation. The authors suggest the technique of falling ball viscometry, using small balls, as a method to determine the effective viscosity of a suspension without affecting the original microstructure significantly. They also describe data from experiments in which the detailed fluctuations of a falling ball's velocity indicate the noncontinuum nature of the suspension and may lead to more insights into the effects of suspension microstructure on macroscopic properties. Finally, they briefly describe other experiments that can be performed in quiescent suspensions (in contrast to the use of conventional shear rotational viscometers) in order to learn more about boundary effects in concentrated suspensions

Explaining global surface aerosol number concentrations in terms of primary emissions and particle formation

Directory of Open Access Journals (Sweden)

D. V. Spracklen

2010-05-01

Full Text Available We synthesised observations of total particle number (CN concentration from 36 sites around the world. We found that annual mean CN concentrations are typically 300–2000 cm⁻³ in the marine boundary layer and free troposphere (FT and 1000–10 000 cm⁻³ in the continental boundary layer (BL. Many sites exhibit pronounced seasonality with summer time concentrations a factor of 2–10 greater than wintertime concentrations. We used these CN observations to evaluate primary and secondary sources of particle number in a global aerosol microphysics model. We found that emissions of primary particles can reasonably reproduce the spatial pattern of observed CN concentration (R²=0.46 but fail to explain the observed seasonal cycle (R²=0.1. The modeled CN concentration in the FT was biased low (normalised mean bias, NMB=−88% unless a secondary source of particles was included, for example from binary homogeneous nucleation of sulfuric acid and water (NMB=−25%. Simulated CN concentrations in the continental BL were also biased low (NMB=−74% unless the number emission of anthropogenic primary particles was increased or a mechanism that results in particle formation in the BL was included. We ran a number of simulations where we included an empirical BL nucleation mechanism either using the activation-type mechanism (nucleation rate, J, proportional to gas-phase sulfuric acid concentration to the power one or kinetic-type mechanism (J proportional to sulfuric acid to the power two with a range of nucleation coefficients. We found that the seasonal CN cycle observed at continental BL sites was better simulated by BL particle formation (R²=0.3 than by increasing the number emission from primary anthropogenic sources (R²=0.18. The nucleation constants that resulted in best overall match between model and observed CN concentrations were

A splitting integration scheme for the SPH simulation of concentrated particle suspensions

Science.gov (United States)

Bian, Xin; Ellero, Marco

2014-01-01

Simulating nearly contacting solid particles in suspension is a challenging task due to the diverging behavior of short-range lubrication forces, which pose a serious time-step limitation for explicit integration schemes. This general difficulty limits severely the total duration of simulations of concentrated suspensions. Inspired by the ideas developed in [S. Litvinov, M. Ellero, X.Y. Hu, N.A. Adams, J. Comput. Phys. 229 (2010) 5457-5464] for the simulation of highly dissipative fluids, we propose in this work a splitting integration scheme for the direct simulation of solid particles suspended in a Newtonian liquid. The scheme separates the contributions of different forces acting on the solid particles. In particular, intermediate- and long-range multi-body hydrodynamic forces, which are computed from the discretization of the Navier-Stokes equations using the smoothed particle hydrodynamics (SPH) method, are taken into account using an explicit integration; for short-range lubrication forces, velocities of pairwise interacting solid particles are updated implicitly by sweeping over all the neighboring pairs iteratively, until convergence in the solution is obtained. By using the splitting integration, simulations can be run stably and efficiently up to very large solid particle concentrations. Moreover, the proposed scheme is not limited to the SPH method presented here, but can be easily applied to other simulation techniques employed for particulate suspensions.

Correlated particle dynamics in concentrated quasi-two-dimensional suspensions

International Nuclear Information System (INIS)

Diamant, H; Cui, B; Lin, B; Rice, S A

2005-01-01

We investigate theoretically and experimentally how the hydrodynamically correlated lateral motion of particles in a suspension confined between two surfaces is affected by the suspension concentration. Despite the long range of the correlations (decaying as 1/r 2 with the inter-particle distance r), the concentration effect is present only at short inter-particle distances for which the static pair correlation is nonuniform. This is in sharp contrast with the effect of hydrodynamic screening in unconfined suspensions, where increasing the concentration changes the prefactor of the large-distance correlation

Particle analysis on concentrated particle suspensions by transmission fluctuation spectrometry with band-pass filters: part 2. Experimental results

International Nuclear Information System (INIS)

Xu, Yamin; Shen, Jianqi; Cai, Xiaoshu; Riebel, Ulrich

2010-01-01

Transmission fluctuation spectrometry (TFS), as a new method of online and real-time particle analysis developed in recent years, can measure the particle size distribution and particle concentration simultaneously. In the preceding paper, high concentration effects on the TFS using band-pass filters were investigated by numerical simulation, and empirical expressions to correct the effects were obtained. This paper presents a study on the TFS measurements in which the particle concentration varies in a very wide dynamic range. Finally, reasonable results on both the particle size distribution and particle concentration are obtained by introducing empirical corrections into the inversion algorithm

EXPOSURE TO CONCENTRATED AMBIENT PARTICLES (CAPS): REVIEW

Science.gov (United States)

Epidemiologic studies support a participation of fine particulate matter (PM) with a diameter of 0.1 to 2.5 microm in the effects of air pollution particles on human health. The ambient fine particle concentrator is a recently developed technology that can enrich the mass of ambi...

Hybrid electrokinetics for separation, mixing, and concentration of colloidal particles

International Nuclear Information System (INIS)

Sin, Mandy L Y; Shimabukuro, Yusuke; Wong, Pak Kin

2009-01-01

The advent of nanotechnology has facilitated the preparation of colloidal particles with adjustable sizes and the control of their size-dependent properties. Physical manipulation, such as separation, mixing, and concentration, of these colloidal particles represents an essential step for fully utilizing their potential in a wide spectrum of nanotechnology applications. In this study, we investigate hybrid electrokinetics, the combination of dielectrophoresis and electrohydrodynamics, for active manipulation of colloidal particles ranging from nanometers to micrometers in size. A concentric electrode configuration, which is optimized for generating electrohydrodynamic flow, has been designed to elucidate the effectiveness of hybrid electrokinetics and define the operating regimes for different microfluidic operations. The results indicate that the relative importance of electrohydrodynamics increases with decreasing particle size as predicted by a scaling analysis and that electrohydrodynamics is pivotal for manipulating nanoscale particles. Using the concentric electrodes, we demonstrate separation, mixing, and concentration of colloidal particles by adjusting the relative strengths of different electrokinetic phenomena. The effectiveness of hybrid electrokinetics indicates its potential to serve as a generic technique for active manipulation of colloidal particles in various nanotechnology applications.

Comparison of Serum Concentrations of Total Cholesterol and Total ...

African Journals Online (AJOL)

Tuberculosis (TB) is one of the most dangerous tropical diseases that complicates HIV infection in Nigeria to date. Over two million Nigerians are known to be infected with TB and many more are at risk of the infection. Serum concentrations of total cholesterol and total lipid of 117 female TB patients attending chest clinic at ...

Preferrential Concentration of Particles in Protoplanetary Nebula Turbulence

Science.gov (United States)

Hartlep, Thomas; Cuzzi, Jeffrey N.

2015-01-01

Preferential concentration in turbulence is a process that causes inertial particles to cluster in regions of high strain (in-between high vorticity regions), with specifics depending on their stopping time or Stokes number. This process is thought to be of importance in various problems including cloud droplet formation and aerosol transport in the atmosphere, sprays, and also in the formation of asteroids and comets in protoplanetary nebulae. In protoplanetary nebulae, the initial accretion of primitive bodies from freely-floating particles remains a problematic subject. Traditional growth-by-sticking models encounter a formidable "meter-size barrier" [1] in turbulent nebulae. One scenario that can lead directly from independent nebula particulates to large objects, avoiding the problematic m-km size range, involves formation of dense clumps of aerodynamically selected, typically mm-size particles in protoplanetary turbulence. There is evidence that at least the ordinary chondrite parent bodies were initially composed entirely of a homogeneous mix of such particles generally known as "chondrules" [2]. Thus, while it is arcane, turbulent preferential concentration acting directly on chondrule size particles are worthy of deeper study. Here, we present the statistical determination of particle multiplier distributions from numerical simulations of particle-laden isotopic turbulence, and a cascade model for modeling turbulent concentration at lengthscales and Reynolds numbers not accessible by numerical simulations. We find that the multiplier distributions are scale dependent at the very largest scales but have scale-invariant properties under a particular variable normalization at smaller scales.

Gravitational settling of a highly concentrated system of solid spherical particles

Science.gov (United States)

Arkhipov, V. A.; Usanina, A. S.

2017-09-01

In the present paper, we report on the results of an experimental study of the process of gravity sedimentation of a cloud of monodispersed solid spherical particles with initial volume concentration C > 0.03, which was performed in a wide range of Reynolds numbers. An analytical estimate of the settling regimes of spherical particle clouds is presented. A new method for creating a spherical particle cloud with a high concentration of particles is proposed. A qualitative picture of the settling process of a highly concentrated particle cloud under gravity is revealed. A criterial dependence for the drag coefficient of a sedimenting spherical particle cloud as an entity is obtained.

Factors affecting the concentration of outdoor particles indoors: Existing data and data needs

International Nuclear Information System (INIS)

McKone, T.E.; Thatcher, T.L.; Fisk, W.J.; Sextro, R.G.; Sohn, M.D.; Delp, W.W.; Riley, W.J.

2002-01-01

Accurate characterization of particle concentrations indoors is critical to exposure assessments. It is estimated that indoor particle concentrations depend strongly on outdoor concentrations. For health scientists, knowledge of the factors that control the relationship of indoor particle concentrations to outdoor levels is particularly important. In this paper, we identify and evaluate sources of data for those factors that affect the transport to and concentration of outdoor particles indoors. To achieve this goal, we (i) identify and assemble relevant information on how particle behavior during air leakage, HVAC operation, and particle filtration effects indoor particle concentration; (ii) review and evaluate the assembled information to distinguish data that are directly relevant to specific estimates of particle transport from those that are only indirectly useful; and (iii) provide a synthesis of the currently available information on building air-leakage parameters and their effect on indoor particle matter concentrations

Evaluation of correlating factors between 238U concentration measured in fine and course atmospheric particles

International Nuclear Information System (INIS)

Peixoto, Claudia Marques; Jacomino, Vanusa Maria Feliciano; Barreto, Alberto Avelar; Dias, Vagner Silva; Dias, Fabiana Ferrari

2009-01-01

Air quality is ever more important in function of the enormous proportion of human actions that have affected the environment over the last two centuries. Particulate material is one among many pollutants that can cause great risk to human health and the environment. It can be classified as: Total Suspended Particles (TSP), defined simply as particles with less than 50 μm aerodynamic diameter (one group of these particles can be inhaled and may cause health problems, while others may unfavorably affect the population's quality of life, interfering in environmental conditions and impairing normal community activities); and Inhalable Particles (PM 10 ), defined as those particles with less than 10 μm aerodynamic diameter. These particles penetrate the respiratory system and can reach pulmonary alveoli due to their small size, causing serious health damage. The Nuclear Technology Development Center (CDTN) has monitored air quality around its installations since 2000. CDTN's Environmental Monitoring Program (EMP) includes monitoring radioactivity levels contained in atmospheric TSP. In order to optimize its program, CDTN is carrying out a study to estimate the correlation between concentrations of particulate material measured in TSP and those measured in PM 10 , PI 2.5 and PI 1 , as well as determination of activity concentration for each controlled radionuclide in all parts. The objective of this study is to present preliminary results and report 238 U activity concentration results. (author)

Characterization of the compounds of nitrogen and total suspended particles in the municipality Regla, Havana

International Nuclear Information System (INIS)

Wallo Vazquez, Antonio; Cuesta Santos, Osvaldo

2006-01-01

The questions related with the atmospheric contamination in urban areas every day they charge bigger importance for the affectations that it can take place so much in the health of the human beings as in the materials, constructions, etc. In the city of Havana those made up of nitrogen and the particles suspended totals are of the pollutants whose concentrations are elevated in the atmosphere. Inside this context, the present work intends the analysis of the behavior of this concentrations, taken as experimental polygon the municipality Regla in city of Havana

Explaining the spatiotemporal variation of fine particle number concentrations over Beijing and surrounding areas in an air quality model with aerosol microphysics

International Nuclear Information System (INIS)

Chen, Xueshun; Wang, Zifa; Li, Jie; Chen, Huansheng; Hu, Min; Yang, Wenyi; Wang, Zhe; Ge, Baozhu; Wang, Dawei

2017-01-01

In this study, a three-dimensional air quality model with detailed aerosol microphysics (NAQPMS + APM) was applied to simulate the fine particle number size distribution and to explain the spatiotemporal variation of fine particle number concentrations in different size ranges over Beijing and surrounding areas in the haze season (Jan 15 to Feb 13 in 2006). Comparison between observations and the simulation indicates that the model is able to reproduce the main features of the particle number size distribution. The high number concentration of total particles, up to 26600 cm −3 in observations and 39800 cm −3 in the simulation, indicates the severity of pollution in Beijing. We find that primary particles with secondary species coating and secondary particles together control the particle number size distribution. Secondary particles dominate particle number concentration in the nucleation mode. Primary and secondary particles together determine the temporal evolution and spatial pattern of particle number concentration in the Aitken mode. Primary particles dominate particle number concentration in the accumulation mode. Over Beijing and surrounding areas, secondary particles contribute at least 80% of particle number concentration in the nucleation mode but only 10–20% in the accumulation mode. Nucleation mode particles and accumulation mode particles are anti-phased with each other. Nucleation or primary emissions alone could not explain the formation of the particle number size distribution in Beijing. Nucleation has larger effects on ultrafine particles while primary particles emissions are efficient in producing large particles in the accumulation mode. Reduction in primary particle emissions does not always lead to a decrease in the number concentration of ultrafine particles. Measures to reduce fine particle pollution in terms of particle number concentration may be different from those addressing particle mass concentration. - Highlights: �

Trends in size classified particle number concentration in subtropical Brisbane, Australia, based on a 5 year study

Science.gov (United States)

Mejía, J. F.; Wraith, D.; Mengersen, K.; Morawska, L.

Particle number size distribution data in the range from 0.015 to 0.630 μm were collected over a 5-year period in the central business district (CBD) of Brisbane, Australia. Particle size distribution was summarised by total number concentration and number median diameter (NMD) as well as the number concentration of the 0.015-0.030 ( N15-30), 0.030-0.050 ( N30-50), 0.050-0.100 ( N50-100), 0.100-0.300 ( N100-300) and 0.300-0.630 ( N300-630) μm size classes. Morning (6:00-10:00) and afternoon (16:00-19:00) measurements, the former representing fresh traffic emissions (based on the local meteorological conditions) and the latter well-mixed emissions from the CBD, during weekdays were extracted and the respective monthly mean values were estimated for time series analysis. For all size fractions, average morning concentrations were about 1.5 higher than in the afternoon whereas NMD did not vary between the morning and afternoon. The trend and seasonal components were extracted through weighted linear regression models, using the monthly variance as weights. Only the morning measurements exhibited significant trends. During this time of the day, total particle number increased by 105.7% and the increase was greater for larger particles, resulting in a shift in NMD by 7.9%. Although no seasonal component was detected the evidence against it remained weak due to the limitations of the database.

Air pollutant concentrations near three Texas roadways, Part I: Ultrafine particles

Science.gov (United States)

Zhu, Yifang; Pudota, Jayanth; Collins, Donald; Allen, David; Clements, Andrea; DenBleyker, Allison; Fraser, Matt; Jia, Yuling; McDonald-Buller, Elena; Michel, Edward

Vehicular emitted air pollutant concentrations were studied near three types of roadways in Austin, Texas: (1) State Highway 71 (SH-71), a heavily traveled arterial highway dominated by passenger vehicles; (2) Interstate 35 (I-35), a limited access highway north of Austin in Georgetown; and (3) Farm to Market Road 973 (FM-973), a heavily traveled surface roadway dominated by truck traffic. Air pollutants examined include carbon monoxide (CO), oxides of nitrogen (NO x), and carbonyl species in the gas-phase. In the particle phase, ultrafine particle (UFP) concentrations (diameter road were found to be the most important factors determining UFP concentrations near the roadways. Since wind directions were not consistent during the sampling periods, distances along wind trajectories from the roadway to the sampling points were used to study the decay characteristics of UFPs. Under perpendicular wind conditions, for all studied roadway types, particle number concentrations increased dramatically moving from the upwind side to the downwind side. The elevated particle number concentrations decay exponentially with increasing distances from the roadway with sharp concentration gradients observed within 100-150 m, similar to previously reported studies. A single exponential decay curve was found to fit the data collected from all three roadways very well under perpendicular wind conditions. No consistent pattern was observed for UFPs under parallel wind conditions. However, regardless of wind conditions, particle concentrations returned to background levels within a few hundred meters of the roadway. Within measured UFP size ranges, smaller particles (6-25 nm) decayed faster than larger ones (100-300 nm). Similar decay rates were observed among UFP number, surface, and volume.

Comparison of Alcian blue and total carbohydrate assays for quantitation of transparent exopolymer particles (TEP) in biofouling studies.

Science.gov (United States)

Li, Xu; Skillman, Lucy; Li, Dan; Ela, Wendell P

2018-04-15

Transparent exopolymer particles (TEP) and their precursors are gel-like acidic polysaccharide particles. Both TEP precursors and TEP have been identified as causal factors in fouling of desalination and water treatment systems. For comparison between studies, it is important to accurately measure the amount and fouling capacity of both components. However, the accuracy and recovery of the currently used Alcian blue based TEP measurement of different surrogates and different size fractions are not well understood. In this study, we compared Alcian blue based TEP measurements with a total carbohydrate assay method. Three surrogates; xanthan gum, pectin and alginic acid; were evaluated at different salinities. Total carbohydrate concentrations of particulates (>0.4 μm) and their precursors (10 kDa) varied depending on water salinity and method of recovery. As xanthan gum is the most frequently used surrogate in fouling studies, TEP concentration is expressed as xanthan gum equivalents (mg XG eq /L) in this study. At a salinity of 35 mg/L sea salt, total carbohydrate assays showed a much higher particulate TEP fraction for alginic acid (38%) compared to xanthan gum (9%) and pectin (12%). The concentrations of particulate TEP therefore may only represent ∼10% of the total mass; while precursor TEP represents ∼80% of the total TEP. This highlights the importance of reporting both particulate and precursor TEP for membrane biofouling studies. The calculated concentrations of TEP and their precursors in seawater samples are also highly dependent on type of surrogate and resulting calibration factor. A linear correlation between TEP recovery and calibration factor was demonstrated in this study for all three surrogates. The relative importance and accuracy of measurement method, particulate size, surrogate type, and recovery are described in detail in this study. Copyright © 2017. Published by Elsevier Ltd.

Determination of particle concentrations in multitemperature plasmas

International Nuclear Information System (INIS)

Richley, E.; Tuma, D.T.

1982-01-01

The use of the multitemperature Saha equation (MSE) of Prigogine 1 and Patapov 2 for calculating particle concentrations in plasmas is shown to be an invalid procedure. Errors greater than one order of magnitude in the electron density in high-pressure argon and nitrogen electric arc plasmas can be easily incurred by using the multitemperature Saha equation. The alternative kinetic method for calculating concentrations is shown to be based on firm concepts. Simpliying procedures and computational techniques for calculating concentrations with the kinetic method are illustrated with examples

Quantification of total aluminium concentrations in food samples at trace levels by INAA and PIGE methods

International Nuclear Information System (INIS)

Nanda, Braja B.; Acharya, R.

2017-01-01

Total aluminium contents in various food samples were determined by Instrumental Neutron Activation Analysis (INAA) and Particle Induced Gamma-ray Emission (PIGE) methods. A total of 16 rice samples, collected from the field, were analyzed by INAA using reactor neutrons from Dhruva reactor. Whereas a total 17 spices collected from market, were analyzed by both INAA and PIGE methods in conjunction with high resolution gamma-ray spectrometry. Aluminium concentration values were found to be in the range of 19-845 mg kg -1 for spices and 15-104 mg kg -1 for rice samples. The methods were validated by analyzing standard reference materials (SRMs) form NIST. (author)

Tire-tread and bitumen particle concentrations in aerosol and soil samples

DEFF Research Database (Denmark)

Fauser, Patrik; Tjell, Jens Christian; Mosbæk, Hans

2002-01-01

% of the mass of airborne particulate tire debris have aerodynamic diameters smaller than 1 mum. The mean aerodynamic diameter is about I gm for the bitumen particles. This size range enables the possibility for far range transport and inhalation by humans. Soil concentrations in the vicinity of a highway...... indicate an approximate exponential decrease with increasing distance from the road. Constant values are reached after about 5 m for the tire particles and 10 m for the bitumen particles. Concentrations in soil that has not been touched for at least 30 years show a decrease in tire concentration...

Inhaled concentrated ambient particles are associated with hematologic and bronchoalveolar lavage changes in canines.

Science.gov (United States)

Clarke, R W; Coull, B; Reinisch, U; Catalano, P; Killingsworth, C R; Koutrakis, P; Kavouras, I; Murthy, G G; Lawrence, J; Lovett, E; Wolfson, J M; Verrier, R L; Godleski, J J

2000-01-01

Pulmonary inflammatory and hematologic responses of canines were studied after exposure to concentrated ambient particles (CAPs) using the Harvard ambient particle concentrator (HAPC). For pulmonary inflammatory studies, normal dogs were exposed in pairs to either CAPs or filtered air (paired studies) for 6 hr/day on 3 consecutive days. For hematologic studies, dogs were exposed for 6 hr/day for 3 consecutive days with one receiving CAPs while the other was simultaneously exposed to filtered air; crossover of exposure took place the following week (crossover studies). Physicochemical characterization of CAPs exposure samples included measurements of particle mass, size distribution, and composition. No statistical differences in biologic responses were found when all CAPs and all sham exposures were compared. However, the variability in biologic response was considerably higher with CAPs exposure. Subsequent exploratory graphical analyses and mixed linear regression analyses suggested associations between CAPs constituents and biologic responses. Factor analysis was applied to the compositional data from paired and crossover experiments to determine elements consistently associated with each other in CAPs samples. In paired experiments, four factors were identified; in crossover studies, a total of six factors were observed. Bronchoalveolar lavage (BAL) and hematologic data were regressed on the factor scores. Increased BAL neutrophil percentage, total peripheral white blood cell (WBC) counts, circulating neutrophils, and circulating lymphocytes were associated with increases in the aluminum/silicon factor. Increased circulating neutrophils and increased BAL macrophages were associated with the vanadium/nickel factor. Increased BAL neutrophils were associated with the bromine/lead factor when only the compositional data from the third day of CAPs exposure were used. Significant decreases in red blood cell counts and hemoglobin levels were correlated with the sulfur

Indoor and ambient air concentrations of respirable particles between two hospitals in Kashan (2014-2015

Directory of Open Access Journals (Sweden)

Mahmoud Mohammadyan

2017-04-01

Full Text Available Background: The hospital environment requires special attention to provide healthful indoor air quality for protecting patients and healthcare workers against the occupational diseases. The aim of this study was to determine the concentrations of respirable particles indoor and ambient air of two hospitals in Kashan. Materials and Method: This cross-sectional study was conducted during 3 months (Marth 2014 to May 2015. Indoor and outdoor PM10 and PM2.5 concentrations were measured four times a week in the operating room, pediatric and ICU2 (Intensive Care Unit wards using a real time dust monitor at two hospitals. A total number of 480 samples (80 samples indoors and 40 outdoors from wards were collected. Results: The highest mean PM2.5 and PM10 for indoors were determined 57.61± 68.57 µg m-3 and 212.36±295.49 µg m-3, respectively. The results showed a significant relationship between PM2.5 and PM10 in the indoor and ambient air of two hospitals (P<0.05. PM2.5 and PM10 concentrations were different in all of the selected wards (P<0.05. Conclusion: The respirable particle concentrations in the indoor and ambient air in both hospitals were higher than the 24-hours WHO and US-EPA standards. Thence, utilizing sufficient and efficient air conditioning systems in hospitals can be useful in improving indoor air quality and reducing the respirable particle concentrations.

Effect of corn grain particle size on ruminal fermentation and blood metabolites of Holstein steers fed total mixed ration

Directory of Open Access Journals (Sweden)

Do Hyung Kim

2018-01-01

Full Text Available Objective This study was conducted to investigate the effect of corn grain particle size on ruminant fermentation and blood metabolites in Holstein steers fed total mixed ration (TMR as a basal diet to explain fundamental data of corn grain for cattle in Korea. Methods Four ruminally cannulated Holstein steers (body weight 592±29.9 kg fed TMR as a basal diet were housed individually in an auto temperature and humidity modulated chamber (24°C and 60% for 22 h/d. Treatments in a 4×4 Latin square design were TMR only (control, TMR with whole corn grain (WC, coarsely ground corn grain (CC, and finely ground corn grain (FC, respectively. The corn feeds substituted for 20% energy intake of TMR intake. To measure the ruminal pH, ammonia N, and volatile fatty acids (VFA, ruminal digesta was sampled through ruminal cannula at 1 h intervals after the morning feeding to determine ruminal fermentation characteristics. Blood was sampled via the jugular vein after the ruminal digesta sampling. Results There was no difference in dry matter (DM intake between different corn particle size because the DM intake was restricted to 1.66% of body weight. Different corn particle size did not change mean ammonia N and total VFA concentrations whereas lower (p<0.05 ruminal pH and a ratio of acetate to propionate, and higher (p<0.05 propionate concentration were noted when the steers consumed CC compared with WC and FC. Concentration of blood metabolites were not affected by different particle size of corn grain except for blood triglyceride concentration, which was significantly (p<0.05 increased by FC. Conclusion Results indicate that feeding CC may increase feed digestion in the rumen, whereas the FC group seemed to obtain inadequate corn retention time for microbial degradation in the rumen.

Fine particle number and mass concentration measurements in urban Indian households.

Science.gov (United States)

Mönkkönen, P; Pai, P; Maynard, A; Lehtinen, K E J; Hämeri, K; Rechkemmer, P; Ramachandran, G; Prasad, B; Kulmala, M

2005-07-15

Fine particle number concentration (D(p)>10 nm, cm(-3)), mass concentrations (approximation of PM(2.5), microg m(-3)) and indoor/outdoor number concentration ratio (I/O) measurements have been conducted for the first time in 11 urban households in India, 2002. The results indicate remarkable high indoor number and mass concentrations and I/O number concentration ratios caused by cooking. Besides cooking stoves that used liquefied petroleum gas (LPG) or kerosene as the main fuel, high indoor concentrations can be explained by poor ventilation systems. Particle number concentrations of more than 300,000 cm(-3) and mass concentrations of more than 1000 microg m(-3) were detected in some cases. When the number and mass concentrations during cooking times were statistically compared, a correlation coefficient r>0.50 was observed in 63% of the households. Some households used other fuels like wood and dung cakes along with the main fuel, but also other living activities influenced the concentrations. In some areas, outdoor combustion processes had a negative impact on indoor air quality. The maximum concentrations observed in most cases were due to indoor combustion sources. Reduction of exposure risk and health effects caused by poor indoor air in urban Indian households is possible by improving indoor ventilation and reducing penetration of outdoor particles.

Indoor particle dynamics in a school office: determination of particle concentrations, deposition rates and penetration factors under naturally ventilated conditions.

Science.gov (United States)

Cong, X C; Zhao, J J; Jing, Z; Wang, Q G; Ni, P F

2018-05-09

Recently, the problem of indoor particulate matter pollution has received much attention. An increasing number of epidemiological studies show that the concentration of atmospheric particulate matter has a significant effect on human health, even at very low concentrations. Most of these investigations have relied upon outdoor particle concentrations as surrogates of human exposures. However, considering that the concentration distribution of the indoor particulate matter is largely dependent on the extent to which these particles penetrate the building and on the degree of suspension in the indoor air, human exposures to particles of outdoor origin may not be equal to outdoor particle concentration levels. Therefore, it is critical to understand the relationship between the particle concentrations found outdoors and those found in indoor micro-environments. In this study, experiments were conducted using a naturally ventilated office located in Qingdao, China. The indoor and outdoor particle concentrations were measured at the same time using an optical counter with four size ranges. The particle size distribution ranged from 0.3 to 2.5 μm, and the experimental period was from April to September, 2016. Based on the experimental data, the dynamic and mass balance model based on time was used to estimate the penetration rate and deposition rate at air exchange rates of 0.03-0.25 h -1 . The values of the penetration rate and deposition velocity of indoor particles were determined to range from 0.45 to 0.82 h -1 and 1.71 to 2.82 m/h, respectively. In addition, the particulate pollution exposure in the indoor environment was analyzed to estimate the exposure hazard from indoor particulate matter pollution, which is important for human exposure to particles and associated health effects. The conclusions from this study can serve to provide a better understanding the dynamics and behaviors of airborne particle entering into buildings. And they will also highlight

Characterization of fluidization regime in circulating fluidized bed reactor with high solid particle concentration using computational fluid dynamics

Energy Technology Data Exchange (ETDEWEB)

Chalermsinsuwan, Benjapon; Thummakul, Theeranan; Piumsomboon, Pornpote [Chulalongkorn University, Bangkok (Thailand); Gidaspow, Dimitri [Armour College of Engineering, Chicago (United States)

2014-02-15

The hydrodynamics inside a high solid particle concentration circulating fluidized bed reactor was investigated using computational fluid dynamics simulation. Compared to a low solid particle reactor, all the conventional fluidization regimes were observed. In addition, two unconventional fluidization regimes, circulating-turbulent and dense suspension bypassing regimes, were found with only primary gas injection. The circulating-turbulent fluidization regime showed uniformly dense solid particle distribution in all the system directions, while the dense suspension bypassing fluidization regime exhibited the flow of solid particles at only one side system wall. Then, comprehensive fluidization regime clarification and mapping were evaluated using in-depth system parameters. In the circulating-turbulent fluidization regime, the total granular temperature was low compared to the adjacent fluidization regimes. In the dense suspension bypassing fluidization regime, the highest total granular temperature was obtained. The circulating-turbulent and dense suspension bypassing fluidization regimes are suitable for sorption and transportation applications, respectively.

Contribution from indoor sources to particle number and mass concentrations in residential houses

Science.gov (United States)

He, Congrong; Morawska, Lidia; Hitchins, Jane; Gilbert, Dale

As part of a large study investigating indoor air in residential houses in Brisbane, Australia, the purpose of this work was to quantify emission characteristics of indoor particle sources in 15 houses. Submicrometer particle number and approximation of PM 2.5 concentrations were measured simultaneously for more than 48 h in the kitchen of all the houses by using a condensation particle counter (CPC) and a photometer (DustTrak), respectively. In addition, characterizations of particles resulting from cooking conducted in an identical way in all the houses were measured by using a scanning mobility particle sizer (SMPS), an aerodynamic particle sizer (APS) and a DustTrak. All the events of elevated particle concentrations were linked to indoor activities using house occupants diary entries, and catalogued into 21 different types of indoor activities. This enabled quantification of the effect of indoor sources on indoor particle concentrations as well as quantification of emission rates from the sources. For example, the study found that frying, grilling, stove use, toasting, cooking pizza, cooking, candle vaporizing eucalyptus oil and fan heater use, could elevate the indoor submicrometer particle number concentration levels by more than five times, while PM 2.5 concentrations could be up to 3, 30 and 90 times higher than the background levels during smoking, frying and grilling, respectively.

Total vs. internal element concentrations in Scots pine needles along a sulphur and metal pollution gradient

International Nuclear Information System (INIS)

Rautio, Pasi; Huttunen, Satu

2003-01-01

Different methods should be used for foliar analyses of trees used as bioindicators of pollution, than those analyses used in nutritional studies of trees. - Analysis of foliar elements is a commonly used method for studying tree nutrition and for monitoring the impacts of air pollutants on forest ecosystems. Interpretations based on the results of foliar element analysis may, however, be different in nutrition vs. monitoring studies. We studied the impacts of severe sulphur and metal (mainly Cu and Ni) pollution on the element concentrations (Al, Ca, Cu, Fe, K, Mg, Mn, Ni, P, Pb, S and Zn) in Scots pine (Pinus sylvestris L.) foliage along an airborne sulphur and metal pollution gradient. Emphasis was put on determining the contribution of air-borne particles that have accumulated on needle surfaces to the total foliage concentrations. A comparison of two soil extraction methods was carried out in order to obtain a reliable estimate of plant-available element concentrations in the soil. Element concentrations in the soil showed only a weak relationship with internal foliar concentrations. There were no clear differences between the total and internal needle S concentrations along the gradient, whereas at the plot closest to the metal smelter complex the total Cu concentrations in the youngest needles were 1.3-fold and Ni concentrations over 1.6-fold higher than the internal needle concentrations. Chloroform-extracted surface wax was found to have Ni and Cu concentrations of as high as 3000 and 600 μg/g of wax, respectively. Our results suggest that bioindicator studies (e.g. monitoring studies) may require different foliar analysis techniques from those used in studies on the nutritional status of trees

Real-time measurement of aerosol particle concentration at high temperatures; Hiukkaspitoisuuden reaaliaikainen mittaaminen korkeassa laempoetilassa

Energy Technology Data Exchange (ETDEWEB)

Keskinen, J; Hautanen, J; Laitinen, A [Tampere Univ. of Technology (Finland). Physics

1997-10-01

The aim of this project is to develop a new method for continuous aerosol particle concentration measurement at elevated temperatures (up to 800-1000 deg C). The measured property of the aerosol particles is the so called Fuchs surface area. This quantity is relevant for diffusion limited mass transfer to particles. The principle of the method is as follows. First, aerosol particles are charged electrically by diffusion charging process. The charging takes place at high temperature. After the charging, aerosol is diluted and cooled. Finally, aerosol particles are collected and the total charge carried by the aerosol particles is measured. Particle collection and charge measurement take place at low temperature. Benefits of this measurement method are: particles are charged in-situ, charge of the particles is not affected by the temperature and pressure changes after sampling, particle collection and charge measurement are carried out outside the process conditions, and the measured quantity is well defined. The results of this study can be used when the formation of the fly ash particles is studied. Another field of applications is the study and the development of gasification processes. Possibly, the method can also be used for the monitoring the operation of the high temperature particle collection devices. (orig.)

Seasonal variations of total suspended particles (TSP) and heavy metals under tropical conditions in Rio de Janeiro, Brazil

International Nuclear Information System (INIS)

Pfeiffer, W.C.; Trindade, H.A.; Costa-Ribeiro, C.; Londres, H.; Oliveira, A.E.

The total suspended particle (TSP) and heavy metal concentrations are studied in Rio de Janeiro, Brazil from 1974 until 1981. The principal aims are to determine how these things vary in two different areas and how meteorological parameters responsible for the transport and dilution of atmospheric pollutants affect these areas. (M.A.C.) [pt

Concentrating small particles in protoplanetary disks through the streaming instability

Science.gov (United States)

Yang, C.-C.; Johansen, A.; Carrera, D.

2017-10-01

Laboratory experiments indicate that direct growth of silicate grains via mutual collisions can only produce particles up to roughly millimeters in size. On the other hand, recent simulations of the streaming instability have shown that mm/cm-sized particles require an excessively high metallicity for dense filaments to emerge. Using a numerical algorithm for stiff mutual drag force, we perform simulations of small particles with significantly higher resolutions and longer simulation times than in previous investigations. We find that particles of dimensionless stopping time τs = 10-2 and 10-3 - representing cm- and mm-sized particles interior of the water ice line - concentrate themselves via the streaming instability at a solid abundance of a few percent. We thus revise a previously published critical solid abundance curve for the regime of τs ≪ 1. The solid density in the concentrated regions reaches values higher than the Roche density, indicating that direct collapse of particles down to mm sizes into planetesimals is possible. Our results hence bridge the gap in particle size between direct dust growth limited by bouncing and the streaming instability.

Extinction of polarized light in ferrofluids with different magnetic particle concentrations

International Nuclear Information System (INIS)

Socoliuc, V.; Popescu, L.B.

2012-01-01

The magnetic field intensity and nanoparticle concentration dependence of the polarized light extinction in a ferrofluid made of magnetite particles stabilized with technical grade oleic acid dispersed in transformer oil was experimentally investigated. The magnetically induced optical anisotropy, i.e. the dichroism divided by concentration, was found to decrease with increasing sample concentration from 2% to 8%. The magnetically induced change in the optical extinction of light polarized at 54.74 o with respect to the magnetic field direction was found to be positive for the less concentrated sample (2%) and negative for the samples with 4% and 8% magnetic nanoparticle concentrations, the more negative the higher the concentration and field intensity. Based on the theoretically proven fact that the particle orientation mechanism has no effect on the extinction of light polarized at 54.74 o with respect to the field direction, we analyzed the experimental findings in the frames of the agglomeration and long-range pair correlations theories for the magnetically induced optical anisotropy in ferrofluids. We developed a theoretical model in the approximation of single scattering for the optical extinction coefficient of a ferrofluid with magnetically induced particle agglomeration. The model predicts the existence of a polarization independent component of the optical extinction coefficient that is experimentally measurable at 54.74 o polarization angle. The change in the optical extinction of light polarized at 54.74 o is positive if only the formation of straight n-particle chains is considered and may become negative in the hypothesis that the longer chains degenerate to more isotropic structures (polymer-like coils, globules or bundles of chains). The model for the influence on the light absorption of the long-range pair correlations, published elsewhere, predicts that the change in the optical extinction of light polarized at 54.74 o is always negative, the more

Measurement of particle size distribution and mass concentration of nuclear fuel aerosols

International Nuclear Information System (INIS)

Pickering, S.

1982-01-01

The particle size distribution and particle mass concentration of a nuclear fuel aerosol is measured by admitting the aerosol into a vertically-extending container, positioning an alpha particle detector within the container so that its window is horizontal and directed vertically, stopping the admission of aerosol into the container, detecting the alpha-activity of the particles of the aerosol sedimenting onto the detector window (for example in a series of equal time intervals until a constant level is reached), and converting the alpha-activity measurements into particle size distribution and/or particle mass concentration measurements. The detector is attached to a pivotted arm and by raising a counterweight can be lowered from the container for cleaning. (author)

[Diagnosis and therapy of particle disease in total hip arthroplasty].

Science.gov (United States)

Müller, M; Wassilew, G; Perka, C

2015-04-01

Particle disease is caused by periarticular accumulation of attrition particles and the inflammatory reaction of the body's tissue. This process may result in osteolysis or soft tissue transformation which presents itself symptomless in the beginning and can proceed to aseptic implant loosening, fracture, implant breaking as a result of the inappropriate osseous support and to algetic and destructive soft tissue reactions as well. Attrition particles originate from tribological pairing, and the extent of the attrition or the particle concentration depend on different factors as there are the tribological pairing's material, the head size, the patient's level of activity, and the implant position. Attrition particles can also be found in the range of any modular connection. Particle disease and its resulting morphological alterations of the tribological pairing is one of the most frequent reasons for re-operation in hip endoprosthetics. Georg Thieme Verlag KG Stuttgart · New York.

Reducing surface water total and methyl mercury concentrations and bioavailability using a coagulation-wetland system

Science.gov (United States)

Kraus, T. E.; Fleck, J.; Henneberry, Y. K.; Stumpner, E. B.; Krabbenhoft, D. P.; Bachand, P.; Randall, P.

2013-12-01

With the recent passage of laws regulating concentrations and loads of mercury (Hg) in surface waters, there is a need to develop management practices that will reduce the export of Hg from both point and non-point sources. Coagulation with metal based salts to remove particles and dissolved organic matter (DOM) from solution is a practice commonly employed by drinking water utilities. Because dissolved Hg is associated with particles and DOM, it follows that Hg should also be removed during the coagulation process and end up associated with the organo-metal precipitate, termed flocculate (floc). The effectiveness of iron- and aluminum-based coagulants for removing both inorganic and methyl mercury (IHg and MeHg, respectively) from solution was demonstrated in laboratory studies conducted on agricultural drainage waters of the Sacramento-San Joaquin Delta: dissolved concentrations of MeHg decreased by 80% while IHg decreased by 97% following coagulation. To test the field application of this technology, samples were collected from the inflows and outflows of wetland treatment cells constructed in the central Delta of California. This replicated field experiment includes three replicates each of three inflow waters treatments: (1) iron sulfate addition, (2) polyaluminum chloride addition, and (3) untreated controls. Water entering and exiting the nine treatment cells was sampled approximately monthly over a 1-year period for total Hg and MeHg in both the dissolved and particulate aqueous phases. Initial results confirm that coagulant addition is removing Hg (total and methyl, particulate and dissolved) from solution and sequestering it in the floc. Seasonal effects on DOM concentration and other factors appear to effect whether passage through the wetland cells alters surface water dissolved organic carbon (DOC) and Hg concentrations. Related studies will examine whether the presence of the floc affects the production and fate of MeHg within the wetland cells. If

Effects of types of ventilation system on indoor particle concentrations in residential buildings.

Science.gov (United States)

Park, J S; Jee, N-Y; Jeong, J-W

2014-12-01

The objective of this study was to quantify the influence of ventilation systems on indoor particle concentrations in residential buildings. Fifteen occupied, single-family apartments were selected from three sites. The three sites have three different ventilation systems: unbalanced mechanical ventilation, balanced mechanical ventilation, and natural ventilation. Field measurements were conducted between April and June 2012, when outdoor air temperatures were comfortable. Number concentrations of particles, PM2.5 and CO2 , were continuously measured both outdoors and indoors. In the apartments with natural ventilation, I/O ratios of particle number concentrations ranged from 0.56 to 0.72 for submicron particles, and from 0.25 to 0.60 for particles larger than 1.0 μm. The daily average indoor particle concentration decreased to 50% below the outdoor level for submicron particles and 25% below the outdoor level for fine particles, when the apartments were mechanically ventilated. The two mechanical ventilation systems reduced the I/O ratios by 26% for submicron particles and 65% for fine particles compared with the natural ventilation. These results showed that mechanical ventilation can reduce exposure to outdoor particles in residential buildings. Results of this study confirm that mechanical ventilation with filtration can significantly reduce indoor particle levels compared with natural ventilation. The I/O ratios of particles substantially varied at the naturally ventilated apartments because of the influence of variable window opening conditions and unsteadiness of wind flow on the penetration of outdoor air particles. For better prediction of the exposure to outdoor particles in naturally ventilated residential buildings, it is important to understand the penetration of outdoor particles with variable window opening conditions. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Scattering by a plane-parallel layer with high concentration of optically soft particles

International Nuclear Information System (INIS)

Loiko, Valery A.; Berdnik, Vladimir V.

2009-01-01

A method describing light propagation in a plane-parallel light-scattering layer with large concentration of homogeneous particles is developed. It is based on the radiative transfer equation and the doubling method. The interference approximation is used to take into account collective scattering effects. Spectral dependence of transmitted light for a layer of nonabsorbing optically soft particles with subwavelength-sized particles is investigated. At small volume concentration of the particles the weak spectral dependences of wave exponents for coherently transmitted and diffuse light are observed. It is shown that in a layer with large volume concentration of the subwavelength-sized particles the wave exponent can exceed considerably the value of four, which takes place for the Rayleigh particles. The dependence of wave exponents for coherently transmitted and diffuse light on the refractive index and concentration of particles is investigated in detail. Multiple scattering of light results in the reduction of the exponent. The quantitative results are presented and discussed. It is shown that there is a range of wavelengths where the negative values of the wave exponent at the regime of multiple scattering are implemented.

Acoustic concentration of particles in fluid flow

Science.gov (United States)

Ward, Michael D.; Kaduchak, Gregory

2010-11-23

An apparatus for acoustic concentration of particles in a fluid flow includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluid flow path to the at least one pressure minima.

Acoustic concentration of particles in fluid flow

Science.gov (United States)

Ward, Michael W.; Kaduchak, Gregory

2017-08-15

Disclosed herein is a acoustic concentration of particles in a fluid flow that includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluid flow path to the at least one pressure minima.

Aircraft observations and model simulations of concentration and particle size distribution in the Eyjafjallajökull volcanic ash cloud

Directory of Open Access Journals (Sweden)

H. F. Dacre

2013-02-01

Full Text Available The Eyjafjallajökull volcano in Iceland emitted a cloud of ash into the atmosphere during April and May 2010. Over the UK the ash cloud was observed by the FAAM BAe-146 Atmospheric Research Aircraft which was equipped with in-situ probes measuring the concentration of volcanic ash carried by particles of varying sizes. The UK Met Office Numerical Atmospheric-dispersion Modelling Environment (NAME has been used to simulate the evolution of the ash cloud emitted by the Eyjafjallajökull volcano during the period 4–18 May 2010. In the NAME simulations the processes controlling the evolution of the concentration and particle size distribution include sedimentation and deposition of particles, horizontal dispersion and vertical wind shear. For travel times between 24 and 72 h, a 1/t relationship describes the evolution of the concentration at the centre of the ash cloud and the particle size distribution remains fairly constant. Although NAME does not represent the effects of microphysical processes, it can capture the observed decrease in concentration with travel time in this period. This suggests that, for this eruption, microphysical processes play a small role in determining the evolution of the distal ash cloud. Quantitative comparison with observations shows that NAME can simulate the observed column-integrated mass if around 4% of the total emitted mass is assumed to be transported as far as the UK by small particles (< 30 μm diameter. NAME can also simulate the observed particle size distribution if a distal particle size distribution that contains a large fraction of < 10 μm diameter particles is used, consistent with the idea that phraetomagmatic volcanoes, such as Eyjafjallajökull, emit very fine particles.

A cosmic-ray nuclear event with an anomalously strong concentration of energy and particles in the central region

International Nuclear Information System (INIS)

Amato, N.M.; Arata, N.; Maldonado, R.H.C.

1986-01-01

A cosmic-ray induced nuclear event detected in the emulsion chamber is described. The event consists of 217 shower cores with ΣEγ = 1,275 TeV. In log scale, energy and particles are emitted most densely at the small lateral distance corresponding to 0.5 mm; 77 % of the total energy and 61 % of the total multiplicity are inside the radius of 0.65 cm. The shower cores in the central region show exponential-type energy distribution and non-isotropic azimuthal distribution. This event indicates a possibility that phenomena of large transverse momentum could happen to produce a strong concentration of energy and particles in the very forward direction. (Authors) [pt

Tangential Flow Ultrafiltration Allows Purification and Concentration of Lauric Acid-/Albumin-Coated Particles for Improved Magnetic Treatment.

Science.gov (United States)

Zaloga, Jan; Stapf, Marcus; Nowak, Johannes; Pöttler, Marina; Friedrich, Ralf P; Tietze, Rainer; Lyer, Stefan; Lee, Geoffrey; Odenbach, Stefan; Hilger, Ingrid; Alexiou, Christoph

2015-08-14

Superparamagnetic iron oxide nanoparticles (SPIONs) are frequently used for drug targeting, hyperthermia and other biomedical purposes. Recently, we have reported the synthesis of lauric acid-/albumin-coated iron oxide nanoparticles SEON(LA-BSA), which were synthesized using excess albumin. For optimization of magnetic treatment applications, SPION suspensions need to be purified of excess surfactant and concentrated. Conventional methods for the purification and concentration of such ferrofluids often involve high shear stress and low purification rates for macromolecules, like albumin. In this work, removal of albumin by low shear stress tangential ultrafiltration and its influence on SEON(LA-BSA) particles was studied. Hydrodynamic size, surface properties and, consequently, colloidal stability of the nanoparticles remained unchanged by filtration or concentration up to four-fold (v/v). Thereby, the saturation magnetization of the suspension can be increased from 446.5 A/m up to 1667.9 A/m. In vitro analysis revealed that cellular uptake of SEON(LA-BSA) changed only marginally. The specific absorption rate (SAR) was not greatly affected by concentration. In contrast, the maximum temperature Tmax in magnetic hyperthermia is greatly enhanced from 44.4 °C up to 64.9 °C by the concentration of the particles up to 16.9 mg/mL total iron. Taken together, tangential ultrafiltration is feasible for purifying and concentrating complex hybrid coated SPION suspensions without negatively influencing specific particle characteristics. This enhances their potential for magnetic treatment.

Concentration, size distribution and dry deposition of amines in atmospheric particles of urban Guangzhou, China

Science.gov (United States)

Liu, Fengxian; Bi, Xinhui; Zhang, Guohua; Peng, Long; Lian, Xiufeng; Lu, Huiying; Fu, Yuzhen; Wang, Xinming; Peng, Ping'an; Sheng, Guoying

2017-12-01

Size-segregated PM10 samples were collected in Guangzhou, China during autumn of 2014. Nine amines, including seven aliphatic amines and two heterocyclic amines, were detected using a gas chromatography-mass spectrometer after derivatization by benzenesulfonyl chloride. The total concentration of the nine amines (Ʃamines) was 79.6-140.9 ng m-3 in PM10. The most abundant species was methylamine (MA), which had a concentration of 29.2-70.1 ng m-3. MA, dimethylamine (DMA), diethylamine (DEA) and dibutylamine (DBA) were the predominant amines in the samples and accounted for approximately 80% of Ʃamines in each size segment. Two heterocyclic amines, pyrrolidine (PYR) and morpholine (MOR), were detected in all samples and had average concentrations of 1.14 ± 0.37 and 1.89 ± 0.64 ng m-3, respectively, in particles with aerodynamic diameters ammonium ranged from 0.0068 to 0.0107 in particles with diameters <1.5 μm, and the maximum ratio occurred in the smallest particles (diameter< 0.49 μm). The average dry deposition flux and velocity of Ʃamines in PM10 were 7.9 ± 1.6 μg m-2 d-1 and 0.084 ± 0.0021 cm s-1, respectively. The results of this study provide essential information on the contribution of amines to secondary organic aerosols and dry removal mechanisms in urban areas.

Totally asymmetric exclusion processes with particles of arbitrary size

CERN Document Server

Lakatos, G

2003-01-01

The steady-state currents and densities of a one-dimensional totally asymmetric exclusion process (TASEP) with particles that occlude an integer number (d) of lattice sites are computed using various mean-field approximations and Monte Carlo simulations. TASEPs featuring particles of arbitrary size are relevant for modelling systems such as mRNA translation, vesicle locomotion along microtubules and protein sliding along DNA. We conjecture that the nonequilibrium steady-state properties separate into low-density, high-density, and maximal current phases similar to those of the standard (d = 1) TASEP. A simple mean-field approximation for steady-state particle currents and densities is found to be inaccurate. However, we find local equilibrium particle distributions derived from a discrete Tonks gas partition function yield apparently exact currents within the maximal current phase. For the boundary-limited phases, the equilibrium Tonks gas distribution cannot be used to predict currents, phase boundaries, or ...

Evaluation and modelling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki - Part I: Modelling results within the LIPIKA project

Science.gov (United States)

Pohjola, M. A.; Pirjola, L.; Karppinen, A.; Härkönen, J.; Korhonen, H.; Hussein, T.; Ketzel, M.; Kukkonen, J.

2007-08-01

A field measurement campaign was conducted near a major road "Itäväylä" in an urban area in Helsinki in 17-20 February 2003. Aerosol measurements were conducted using a mobile laboratory "Sniffer" at various distances from the road, and at an urban background location. Measurements included particle size distribution in the size range of 7 nm-10 μm (aerodynamic diameter) by the Electrical Low Pressure Impactor (ELPI) and in the size range of 3-50 nm (mobility diameter) by Scanning Mobility Particle Sizer (SMPS), total number concentration of particles larger than 3 nm detected by an ultrafine condensation particle counter (UCPC), temperature, relative humidity, wind speed and direction, driving route of the mobile laboratory, and traffic density on the studied road. In this study, we have compared measured concentration data with the predictions of the road network dispersion model CAR-FMI used in combination with an aerosol process model MONO32. For model comparison purposes, one of the cases was additionally computed using the aerosol process model UHMA, combined with the CAR-FMI model. The vehicular exhaust emissions, and atmospheric dispersion and transformation of fine and ultrafine particles was evaluated within the distance scale of 200 m (corresponding to a time scale of a couple of minutes). We computed the temporal evolution of the number concentrations, size distributions and chemical compositions of various particle size classes. The atmospheric dilution rate of particles is obtained from the roadside dispersion model CAR-FMI. Considering the evolution of total number concentration, dilution was shown to be the most important process. The influence of coagulation and condensation on the number concentrations of particle size modes was found to be negligible on this distance scale. Condensation was found to affect the evolution of particle diameter in the two smallest particle modes. The assumed value of the concentration of condensable organic

Concentration levels and source apportionment of ultrafine particles in road microenvironments

Science.gov (United States)

Argyropoulos, G.; Samara, C.; Voutsa, D.; Kouras, A.; Manoli, E.; Voliotis, A.; Tsakis, A.; Chasapidis, L.; Konstandopoulos, A.; Eleftheriadis, K.

2016-03-01

A mobile laboratory unit (MOBILAB) with on-board instrumentation (Scanning Mobility Particle Sizer, SMPS; Ambient NOx analyzer) was used to measure size-resolved particle number concentrations (PNCs) of quasi-ultrafine particles (UFPs, 9-372 nm), along with NOx, in road microenvironments. On-road measurements were carried out in and around a large Greek urban agglomeration, the Thessaloniki Metropolitan Area (TMA). Two 2-week measurement campaigns were conducted during the warm period of 2011 and the cold period of 2012. During each sampling campaign, MOBILAB was driven through a 5-day inner-city route and a second 5-day external route covering in total a wide range of districts (urban, urban background, industrial and residential), and road types (major and minor urban roads, freeways, arterial and interurban roads). All routes were conducted during working days, in morning and in afternoon hours under real-world traffic conditions. Spatial classification of MOBILAB measurements involved the assignment of measurement points to location bins defined by the aspect ratio of adjacent urban street canyons (USCs). Source apportionment was further carried out, by applying Positive Matrix Factorization (PMF) to particle size distribution data. Apportioned PMF factors were interpreted, by employing a two-step methodology, which involved (a) statistical association of PMF factor contributions with 12 h air-mass back-trajectories ending at the TMA during MOBILAB measurements, and (b) Multiple Linear Regression (MLR) using PMF factor contributions as the dependent variables, while relative humidity, solar radiation flux, and vehicle speed were used as the independent variables. The applied data analysis showed that low-speed cruise and high-load engine operation modes are the two dominant sources of UFPs in most of the road microenvironments in the TMA, with significant contributions from background photochemical processes during the warm period, explaining the reversed

Nonimaging light concentration using total internal reflection films.

Science.gov (United States)

Ouellette, G; Waltham, C E; Drees, R M; Poon, A; Schubank, R; Whitehead, L A

1992-05-01

We present a method of fabricating nonimaging light concentrators from total internal reflection film. A prototype has been made and tested and found to operate in agreement with predictions of ray-tracing codes. The performance of the prototype is comparable with that of concentrators made from specular reflecting materials.

COOKING-RELATED PARTICLE CONCENTRATIONS MEASURED IN AN OCCUPIED TOWNHOME IN RESTON, VA

Science.gov (United States)

In non-smoking households, cooking is one of the most significant sources of indoor particles. To date, there are limited data available regarding indoor particle concentrations generated by different types of cooking. To increase the knowledge base associated with particles ...

Differences in airborne particle and gaseous concentrations in urban air between weekdays and weekends

Science.gov (United States)

Morawska, L.; Jayaratne, E. R.; Mengersen, K.; Jamriska, M.; Thomas, S.

Airborne particle number concentrations and size distributions as well as CO and NO x concentrations monitored at a site within the central business district of Brisbane, Australia were correlated with the traffic flow rate on a nearby freeway with the aim of investigating differences between weekday and weekend pollutant characteristics. Observations over a 5-year monitoring period showed that the mean number particle concentration on weekdays was (8.8±0.1)×10 3 cm -3 and on weekends (5.9±0.2)×10 3 cm -3—a difference of 47%. The corresponding mean particle number median diameters during weekdays and weekends were 44.2±0.3 and 50.2±0.2 nm, respectively. The differences in mean particle number concentration and size between weekdays and weekends were found to be statistically significant at confidence levels of over 99%. During a 1-year period of observation, the mean traffic flow rate on the freeway was 14.2×10 4 and 9.6×10 4 vehicles per weekday and weekend day, respectively—a difference of 48%. The mean diurnal variations of the particle number and the gaseous concentrations closely followed the traffic flow rate on both weekdays and weekends (correlation coefficient of 0.86 for particles). The overall conclusion, as to the effect of traffic on concentration levels of pollutant concentration in the vicinity of a major road (about 100 m) carrying traffic of the order of 10 5 vehicles per day, is that about a 50% increase in traffic flow rate results in similar increases of CO and NO x concentrations and a higher increase of about 70% in particle number concentration.

Total protein and cholesterol concentrations in brain regions of male ...

African Journals Online (AJOL)

The results showed similarities (P>0.05) between the treatments in total protein concentrations in the cerebral cortex, medulla, hypothalamus, amygdala, mesencephalon and hippocampus. Total protein concentrations however differed significantly between diets (P<0.05) in the cerebellum and pons varoli with the lowest ...

Concentration and characterization of airborne particles in Tehran's subway system.

Science.gov (United States)

Kamani, Hosein; Hoseini, Mohammad; Seyedsalehi, Mahdi; Mahdavi, Yousef; Jaafari, Jalil; Safari, Gholam Hosein

2014-06-01

Particulate matter is an important air pollutant, especially in closed environments like underground subway stations. In this study, a total of 13 elements were determined from PM10 and PM2.5 samples collected at two subway stations (Imam Khomeini and Sadeghiye) in Tehran's subway system. Sampling was conducted in April to August 2011 to measure PM concentrations in platform and adjacent outdoor air of the stations. In the Imam Khomeini station, the average concentrations of PM10 and PM2.5 were 94.4 ± 26.3 and 52.3 ± 16.5 μg m(-3) in the platform and 81.8 ± 22.2 and 35 ± 17.6 μg m(-3) in the outdoor air, respectively. In the Sadeghiye station, mean concentrations of PM10 and PM2.5 were 87.6 ± 23 and 41.3 ± 20.4 μg m(-3) in the platform and 73.9 ± 17.3 and 30 ± 15 μg m(-3), in the outdoor air, respectively. The relative contribution of elemental components in each particle fraction were accounted for 43% (PM10) and 47.7% (PM2.5) in platform of Imam Khomeini station and 15.9% (PM10) and 18.5% (PM2.5) in the outdoor air of this station. Also, at the Sadeghiye station, each fraction accounted for 31.6% (PM10) and 39.8% (PM2.5) in platform and was 11.7% (PM10) and 14.3% (PM2.5) in the outdoor. At the Imam Khomeini station, Fe was the predominant element to represent 32.4 and 36 % of the total mass of PM10 and PM2.5 in the platform and 11.5 and 13.3% in the outdoor, respectively. At the Sadeghiye station, this element represented 22.7 and 29.8% of total mass of PM10 and PM2.5 in the platform and 8.7 and 10.5% in the outdoor air, respectively. Other major crustal elements were 5.8% (PM10) and 5.3% (PM2.5) in the Imam Khomeini station platform and 2.3 and 2.4% in the outdoor air, respectively. The proportion of other minor elements was significantly lower, actually less than 7% in total samples, and V was the minor concentration in total mass of PM10 and PM2.5 in both platform stations.

Mathematical modeling of atmospheric fine particle-associated primary organic compound concentrations

Science.gov (United States)

Rogge, Wolfgang F.; Hildemann, Lynn M.; Mazurek, Monica A.; Cass, Glen R.; Simoneit, Bernd R. T.

1996-08-01

An atmospheric transport model has been used to explore the relationship between source emissions and ambient air quality for individual particle phase organic compounds present in primary aerosol source emissions. An inventory of fine particulate organic compound emissions was assembled for the Los Angeles area in the year 1982. Sources characterized included noncatalyst- and catalyst-equipped autos, diesel trucks, paved road dust, tire wear, brake lining dust, meat cooking operations, industrial oil-fired boilers, roofing tar pots, natural gas combustion in residential homes, cigarette smoke, fireplaces burning oak and pine wood, and plant leaf abrasion products. These primary fine particle source emissions were supplied to a computer-based model that simulates atmospheric transport, dispersion, and dry deposition based on the time series of hourly wind observations and mixing depths. Monthly average fine particle organic compound concentrations that would prevail if the primary organic aerosol were transported without chemical reaction were computed for more than 100 organic compounds within an 80 km × 80 km modeling area centered over Los Angeles. The monthly average compound concentrations predicted by the transport model were compared to atmospheric measurements made at monitoring sites within the study area during 1982. The predicted seasonal variation and absolute values of the concentrations of the more stable compounds are found to be in reasonable agreement with the ambient observations. While model predictions for the higher molecular weight polycyclic aromatic hydrocarbons (PAH) are in agreement with ambient observations, lower molecular weight PAH show much higher predicted than measured atmospheric concentrations in the particle phase, indicating atmospheric decay by chemical reactions or evaporation from the particle phase. The atmospheric concentrations of dicarboxylic acids and aromatic polycarboxylic acids greatly exceed the contributions that

Spatial & temporal variations of PM10 and particle number concentrations in urban air.

Science.gov (United States)

Johansson, Christer; Norman, Michael; Gidhagen, Lars

2007-04-01

The size of particles in urban air varies over four orders of magnitude (from 0.001 microm to 10 microm in diameter). In many cities only particle mass concentrations (PM10, i.e. particles tires and traction sand on streets during winter; up to 90% of the locally emitted PM10 may be due to road abrasion. PM10 emissions and concentrations, but not PNC, at kerbside are controlled by road moisture. Annual mean urban background PM10 levels are relatively uniformly distributed over the city, due to the importance of long range transport. For PNC local sources often dominate the concentrations resulting in large temporal and spatial gradients in the concentrations. Despite these differences in the origin of PM10 and PNC, the spatial gradients of annual mean concentrations due to local sources are of equal magnitude due to the common source, namely traffic. Thus, people in different areas experiencing a factor of 2 different annual PM10 exposure due to local sources will also experience a factor of 2 different exposure in terms of PNC. This implies that health impact studies based solely on spatial differences in annual exposure to PM10 may not separate differences in health effects due to ultrafine and coarse particles. On the other hand, health effect assessments based on time series exposure analysis of PM10 and PNC, should be able to observe differences in health effects of ultrafine particles versus coarse particles.

Errors analysis in the evaluation of particle concentration by PDA on a turbulent two-phase jet: application for cross section and transit time methods

Science.gov (United States)

Calvo, Esteban; García, Juan A.; García, Ignacio; Aísa, Luis A.

2009-09-01

Phase-Doppler anemometry (PDA) is a powerful tool for two-phase flow measurements and testing. Particle concentration and mass flux can also be evaluated using the raw particle data supplied by this technique. The calculation starts from each particle velocity, diameter, transit time data, and the total measurement time. There are two main evaluation strategies. The first one uses the probe volume effective cross section, and it is usually simplified assuming that particles follow quasi one-directional trajectories. In the text, it will be called the cross section method. The second one includes a set of methods which will be denoted as “Generalized Integral Methods” (GIM). Concentration algorithms such as the transit time method (TTM) and the integral volume method (IVM) are particular cases of the GIM. In any case, a previous calibration of the measurement volume geometry is necessary to apply the referred concentration evaluation methods. In this study, concentrations and mass fluxes both evaluated by the cross-section method and the TTM are compared. Experimental data are obtained from a particle-laden jet generated by a convergent nozzle. Errors due to trajectory dispersion, burst splitting, and multi-particle signals are discussed.

Errors analysis in the evaluation of particle concentration by PDA on a turbulent two-phase jet: application for cross section and transit time methods

Energy Technology Data Exchange (ETDEWEB)

Calvo, Esteban; Garcia, Juan A.; Garcia, Ignacio; Aisa, Luis A. [University of Zaragoza, Area de Mecanica de Fluidos, Centro Politecnico Superior, Zaragoza (Spain)

2009-09-15

Phase-Doppler anemometry (PDA) is a powerful tool for two-phase flow measurements and testing. Particle concentration and mass flux can also be evaluated using the raw particle data supplied by this technique. The calculation starts from each particle velocity, diameter, transit time data, and the total measurement time. There are two main evaluation strategies. The first one uses the probe volume effective cross section, and it is usually simplified assuming that particles follow quasi one-directional trajectories. In the text, it will be called the cross section method. The second one includes a set of methods which will be denoted as ''Generalized Integral Methods'' (GIM). Concentration algorithms such as the transit time method (TTM) and the integral volume method (IVM) are particular cases of the GIM. In any case, a previous calibration of the measurement volume geometry is necessary to apply the referred concentration evaluation methods. In this study, concentrations and mass fluxes both evaluated by the cross-section method and the TTM are compared. Experimental data are obtained from a particle-laden jet generated by a convergent nozzle. Errors due to trajectory dispersion, burst splitting, and multi-particle signals are discussed. (orig.)

Evaluation and modelling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki ─ Part I: Modelling results within the LIPIKA project

Directory of Open Access Journals (Sweden)

M. Ketzel

2007-08-01

Full Text Available A field measurement campaign was conducted near a major road "Itäväylä" in an urban area in Helsinki in 17–20 February 2003. Aerosol measurements were conducted using a mobile laboratory "Sniffer" at various distances from the road, and at an urban background location. Measurements included particle size distribution in the size range of 7 nm–10 μm (aerodynamic diameter by the Electrical Low Pressure Impactor (ELPI and in the size range of 3–50 nm (mobility diameter by Scanning Mobility Particle Sizer (SMPS, total number concentration of particles larger than 3 nm detected by an ultrafine condensation particle counter (UCPC, temperature, relative humidity, wind speed and direction, driving route of the mobile laboratory, and traffic density on the studied road. In this study, we have compared measured concentration data with the predictions of the road network dispersion model CAR-FMI used in combination with an aerosol process model MONO32. For model comparison purposes, one of the cases was additionally computed using the aerosol process model UHMA, combined with the CAR-FMI model. The vehicular exhaust emissions, and atmospheric dispersion and transformation of fine and ultrafine particles was evaluated within the distance scale of 200 m (corresponding to a time scale of a couple of minutes. We computed the temporal evolution of the number concentrations, size distributions and chemical compositions of various particle size classes. The atmospheric dilution rate of particles is obtained from the roadside dispersion model CAR-FMI. Considering the evolution of total number concentration, dilution was shown to be the most important process. The influence of coagulation and condensation on the number concentrations of particle size modes was found to be negligible on this distance scale. Condensation was found to affect the evolution of particle diameter in the two smallest particle modes. The assumed value of the concentration of

Radon in indoor concentrations and indoor concentrations of metal dust particles in museums and other public buildings.

Science.gov (United States)

Carneiro, G L; Braz, D; de Jesus, E F; Santos, S M; Cardoso, K; Hecht, A A; Dias da Cunha, Moore K

2013-06-01

The aim of this study was to evaluate the public and occupational exposure to radon and metal-bearing particles in museums and public buildings located in the city of Rio de Janeiro, Brazil. For this study, four buildings were selected: two historic buildings, which currently house an art gallery and an art museum; and two modern buildings, a chapel and a club. Integrated radon concentration measurements were performed using passive radon detectors with solid state nuclear track detector-type Lexan used as nuclear track detector. Air samplers with a cyclone were used to collect the airborne particle samples that were analyzed by the particle-induced X-ray emission technique. The average unattached-radon concentrations in indoor air in the buildings were above 40 Bq/m(3), with the exception of Building D as measured in 2009. The average radon concentrations in indoor air in the four buildings in 2009 were below the recommended reference level by World Health Organization (100 Bq/m(3)); however, in 2011, the average concentrations of radon in Buildings A and C were above this level, though lower than 300 Bq/m(3). The average concentrations of unattached radon were lower than 148 Bq/m(3) (4pCi/L), the USEPA level recommended to take action to reduce the concentrations of radon in indoor air. The unattached-radon average concentrations were also lower than the value recommended by the European Union for new houses. As the unattached-radon concentrations were below the international level recommended to take action to reduce the radon concentration in air, it was concluded that during the period of sampling, there was low risk to human health due to the inhalation of unattached radon in these four buildings.

The particle concentration effect on magnetic resonance linewidth for magnetic liquids with chain aggregates

International Nuclear Information System (INIS)

Marin, C.N.

2002-01-01

Based on the assumption of particle chains formation within a magnetic liquid, computer simulation of the magnetic resonance line is presented. The dependence on particle concentration within a magnetic liquid of magnetic resonance linewidth is analyzed. The computer simulation demonstrates that the particles chaining has an important effect on the enlargement of the magnetic resonance line. Increasing the particle concentration within magnetic liquid leads to an increase in the linewidth. The agreement with some experimental findings is discussed

Atmospheric concentration characteristics and gas-particle partitioning of PCBs in a rural area of eastern Germany

International Nuclear Information System (INIS)

Mandalakis, Manolis; Stephanou, Euripides G.

2007-01-01

Atmospheric concentrations of polychlorinated biphenyls (PCBs) were measured in 14 successive daytime and nighttime air samples collected from Melpitz, a rural site in eastern Germany. The average total concentration of PCBs was 110+/-80pgm -3 and they were predominately present in the gas phase (∼95%). Composition of individual congeners closely resembled those of Clophen A30 and Aroclor 1232. Partial vapor pressures of PCBs were well correlated with temperature and the steep slopes obtained from Clausius-Clapeyron plots (-4500 to -8000) indicated that evaporation from adjacent land surfaces still controls the atmospheric levels of these pollutants. Particle-gas partitioning coefficients (K P ) of PCBs were well correlated with the respective sub-cooled vapor pressures (P L o ), but the slopes obtained from logK P versus logP L o plots (-0.16 to -0.59) deviated significantly from the expected value of -1. Overall, gas-particle partitioning of PCBs was better simulated by Junge-Pankow than octanol/air partition coefficient-based model

Fluidized bed combustion of single coal char particles at high CO{sub 2} concentration

Energy Technology Data Exchange (ETDEWEB)

Scala, F.; Chirone, R. [CNR, Naples (Italy)

2010-12-15

Combustion of single coal char particles was studied at 850{sup o}C in a lab-scale fluidized bed at high CO{sub 2} concentration, typical of oxyfiring conditions. The burning rate of the particles was followed as a function of time by continuously measuring the outlet CO and O{sub 2} concentrations. Some preliminary evaluations on the significance of homogeneous CO oxidation in the reactor and of carbon gasification by CO{sub 2} in the char were also carried out. Results showed that the carbon burning rate increases with oxygen concentration and char particle size. The particle temperature is approximately equal to that of the bed up to an oxygen concentration of 2%, but it is considerably higher for larger oxygen concentrations. Both CO{sub 2} gasification of char and homogeneous CO oxidation are not negligible. The gasification reaction rate is slow and it is likely to be controlled by intrinsic kinetics. During purely gasification conditions the extent of carbon loss due to particle attrition by abrasion (estimated from the carbon mass balance) appears to be much more important than under combustion conditions.

Summer-winter concentrations and gas-particle partitioning of short chain chlorinated paraffins in the atmosphere of an urban setting.

Science.gov (United States)

Wang, Thanh; Han, Shanlong; Yuan, Bo; Zeng, Lixi; Li, Yingming; Wang, Yawei; Jiang, Guibin

2012-12-01

Short chain chlorinated paraffins (SCCPs) are semi-volatile chemicals that are considered persistent in the environment, potential toxic and subject to long-range transport. This study investigates the concentrations and gas-particle partitioning of SCCPs at an urban site in Beijing during summer and wintertime. The total atmospheric SCCP levels ranged 1.9-33.0 ng/m(3) during wintertime. Significantly higher levels were found during the summer (range 112-332 ng/m(3)). The average fraction of total SCCPs in the particle phase (ϕ) was 0.67 during wintertime but decreased significantly during the summer (ϕ = 0.06). The ten and eleven carbon chain homologues with five to eight chlorine atoms were the predominant SCCP formula groups in air. Significant linear correlations were found between the gas-particle partition coefficients and the predicted subcooled vapor pressures and octanol-air partition coefficients. The gas-particle partitioning of SCCPs was further investigated and compared with both the Junge-Pankow adsorption and K(oa)-based absorption models. Copyright © 2012 Elsevier Ltd. All rights reserved.

Estimation of inhaled airborne particle number concentration by subway users in Seoul, Korea

International Nuclear Information System (INIS)

Kim, Minhae; Park, Sechan; Namgung, Hyeong-Gyu; Kwon, Soon-Bark

2017-01-01

Exposure to airborne particulate matter (PM) causes several diseases in the human body. The smaller particles, which have relatively large surface areas, are actually more harmful to the human body since they can penetrate deeper parts of the lungs or become secondary pollutants by bonding with other atmospheric pollutants, such as nitrogen oxides. The purpose of this study is to present the number of PM inhaled by subway users as a possible reference material for any analysis of the hazards to the human body arising from the inhalation of such PM. Two transfer stations in Seoul, Korea, which have the greatest number of users, were selected for this study. For 0.3–0.422 μm PM, particle number concentration (PNC) was highest outdoors but decreased as the tester moved deeper underground. On the other hand, the PNC between 1 and 10 μm increased as the tester moved deeper underground and showed a high number concentration inside the subway train as well. An analysis of the particles to which subway users are actually exposed to (inhaled particle number), using particle concentration at each measurement location, the average inhalation rate of an adult, and the average stay time at each location, all showed that particles sized 0.01–0.422 μm are mostly inhaled from the outdoor air whereas particles sized 1–10 μm are inhaled as the passengers move deeper underground. Based on these findings, we expect that the inhaled particle number of subway users can be used as reference data for an evaluation of the hazards to health caused by PM inhalation. - Highlights: • Size-dependent aerosol number was measured along the path of subway user. • Particles less than 0.4 μm were inhaled in outdoor but less so as deeper underground. • Coarse particles were inhaled significantly as users moved deeper underground. - We estimated the inhaled aerosol number concentration depending on particle size along the path of subway users.

Comparison of sources of submicron particle number concentrations measured at two sites in Rochester, NY.

Science.gov (United States)

Kasumba, John; Hopke, Philip K; Chalupa, David C; Utell, Mark J

2009-09-01

Sources contributing to the submicron particles (100-470 nm) measured between January 2002 and December 2007 at two different New York State Department of Environmental Conservation (NYS DEC) sites in Rochester, NY were identified and apportioned using a bilinear receptor model, positive matrix factorization (PMF). Measurements of aerosol size distributions and number concentrations for particles in the size range of 10-500 nm have been made since December 2001 to date in Rochester. The measurements are being made using a scanning mobility particle sizer (SMPS) consisting of a DMA and a CPC (TSI models 3071 and 3010, respectively). From December 2001 to March 2004, particle measurements were made at the NYS DEC site in downtown Rochester, but it was moved to the eastside of Rochester in May 2004. Each measurement period was divided into three seasons i.e., winter (December, January, and February), summer (June, July, and August), and the transitional periods (March, April, May, September, October, and November) so as to avoid experimental uncertainty resulting from too large season-to-season variability in ambient temperature and solar photon intensity that would lead to unstable/non-stationary size distributions. Therefore, the seasons were analyzed independently for possible sources. Ten sources were identified at both sites and these include traffic, nucleation, residential/commercial heating, industrial emissions, secondary nitrate, ozone- rich secondary aerosol, secondary sulfate, regionally transported aerosol, and a mixed source of nucleation and traffic. These results show that the measured total outdoor particle number concentrations in Rochester generally vary with similar temporal patterns, suggesting that the central monitoring site data can be used to estimate outdoor exposure in other parts of the city.

Physicochemical characterization of Capstone depleted uranium aerosols I: uranium concentration in aerosols as a function of time and particle size.

Science.gov (United States)

Parkhurst, Mary Ann; Cheng, Yung Sung; Kenoyer, Judson L; Traub, Richard J

2009-03-01

During the Capstone Depleted Uranium (DU) Aerosol Study, aerosols containing DU were produced inside unventilated armored vehicles (i.e., Abrams tanks and Bradley Fighting Vehicles) by perforation with large-caliber DU penetrators. These aerosols were collected and characterized, and the data were subsequently used to assess human health risks to personnel exposed to DU aerosols. The DU content of each aerosol sample was first quantified by radioanalytical methods, and selected samples, primarily those from the cyclone separator grit chambers, were analyzed radiochemically. Deposition occurred inside the vehicles as particles settled on interior surfaces. Settling rates of uranium from the aerosols were evaluated using filter cassette samples that collected aerosol as total mass over eight sequential time intervals. A moving filter was used to collect aerosol samples over time, particularly within the first minute after a shot. The results demonstrate that the peak uranium concentration in the aerosol occurred in the first 10 s after perforation, and the concentration decreased in the Abrams tank shots to about 50% within 1 min and to less than 2% after 30 min. The initial and maximum uranium concentrations were lower in the Bradley vehicle than those observed in the Abrams tank, and the concentration levels decreased more slowly. Uranium mass concentrations in the aerosols as a function of particle size were evaluated using samples collected in a cyclone sampler, which collected aerosol continuously for 2 h after perforation. The percentages of uranium mass in the cyclone separator stages ranged from 38 to 72% for the Abrams tank with conventional armor. In most cases, it varied with particle size, typically with less uranium associated with the smaller particle sizes. Neither the Abrams tank with DU armor nor the Bradley vehicle results were specifically correlated with particle size and can best be represented by their average uranium mass concentrations of 65

The variation of particle gas-borne concentration with time in a gas cooled reactor

International Nuclear Information System (INIS)

Reed, J.; Hall, D.; Reeks, M.W.

1985-01-01

If volatile fission products are released from fuel during a reactor fault, a significant fraction could become attached to small particles also present in the coolant. In such circumstances the retention of those particles by the reactor circuit will limit the level of gas-borne particle concentration and hence be important in reducing the potential release of fission product activity to the atmosphere. Clearly the retention of particles will be influenced by both the deposition and resuspension of particles from surfaces exposed to the coolant flow. In this paper we consider deposition and resuspension but pay particular attention to the role of resuspension, which in the past has been given little consideration. A recently developed model for the resuspension of small particles by a turbulent flow is outlined. Traditionally, resuspension has been interpreted as a force balance between the aerodynamic removal forces and the surface adhesive forces. In contrast, this new approach embodies an energy balance criterion for particle resuspension. Furthermore, the stochastic nature of this new model has shown that resuspension can be sub-divided into two regimes: (i) initial resuspension (resuspension occurring in times less than a second) which reduces the net deposition of particles to a surface; and (ii) longer term resuspension (resuspension after 1 second) which determines the asymptotic decay of particle gas-borne concentration. It is seen that the asymptotic decay varies almost inversely as the decay time. Force balance models are unsuccessful in accounting for the experimentally observed longer term resuspension. We show that a Volterra integro-differential equation best describes the variation of particle gas-borne concentration with time in a recirculating gas flow such as a gas cooled reactor. It is seen that the longer term resuspension has a major influence in the final decay of particle concentration. (author)

The variation of particle gas-borne concentration with time in a gas cooled reactor

Energy Technology Data Exchange (ETDEWEB)

Reed, J; Hall, D; Reeks, M W [Central Electricity Generating Board, Berkeley Nuclear Laboratories (United Kingdom)

1985-07-01

If volatile fission products are released from fuel during a reactor fault, a significant fraction could become attached to small particles also present in the coolant. In such circumstances the retention of those particles by the reactor circuit will limit the level of gas-borne particle concentration and hence be important in reducing the potential release of fission product activity to the atmosphere. Clearly the retention of particles will be influenced by both the deposition and resuspension of particles from surfaces exposed to the coolant flow. In this paper we consider deposition and resuspension but pay particular attention to the role of resuspension, which in the past has been given little consideration. A recently developed model for the resuspension of small particles by a turbulent flow is outlined. Traditionally, resuspension has been interpreted as a force balance between the aerodynamic removal forces and the surface adhesive forces. In contrast, this new approach embodies an energy balance criterion for particle resuspension. Furthermore, the stochastic nature of this new model has shown that resuspension can be sub-divided into two regimes: (i) initial resuspension (resuspension occurring in times less than a second) which reduces the net deposition of particles to a surface; and (ii) longer term resuspension (resuspension after 1 second) which determines the asymptotic decay of particle gas-borne concentration. It is seen that the asymptotic decay varies almost inversely as the decay time. Force balance models are unsuccessful in accounting for the experimentally observed longer term resuspension. We show that a Volterra integro-differential equation best describes the variation of particle gas-borne concentration with time in a recirculating gas flow such as a gas cooled reactor. It is seen that the longer term resuspension has a major influence in the final decay of particle concentration. (author)

Estimate of main local sources to ambient ultrafine particle number concentrations in an urban area

Science.gov (United States)

Rahman, Md Mahmudur; Mazaheri, Mandana; Clifford, Sam; Morawska, Lidia

2017-09-01

Quantifying and apportioning the contribution of a range of sources to ultrafine particles (UFPs, D oil refineries, and seaport) sources to the total ambient particle number concentration (PNC) in a busy, inner-city area in Brisbane, Australia using Bayesian statistical modelling and other exploratory tools. The Bayesian model was trained on the PNC data on days where NP formations were known to have not occurred, hourly traffic counts, solar radiation data, and smooth daily trend. The model was applied to apportion and quantify the contribution of NP formations and local traffic and non-traffic sources to UFPs. The data analysis incorporated long-term measured time-series of total PNC (D ≥ 6 nm), particle number size distributions (PSD, D = 8 to 400 nm), PM2.5, PM10, NOx, CO, meteorological parameters and traffic counts at a stationary monitoring site. The developed Bayesian model showed reliable predictive performances in quantifying the contribution of NP formation events to UFPs (up to 4 × 104 particles cm- 3), with a significant day to day variability. The model identified potential NP formation and no-formations days based on PNC data and quantified the sources contribution to UFPs. Exploratory statistical analyses show that total mean PNC during the middle of the day was up to 32% higher than during peak morning and evening traffic periods, which were associated with NP formation events. The majority of UFPs measured during the peak traffic and NP formation periods were between 30-100 nm and smaller than 30 nm, respectively. To date, this is the first application of Bayesian model to apportion different sources contribution to UFPs, and therefore the importance of this study is not only in its modelling outcomes but in demonstrating the applicability and advantages of this statistical approach to air pollution studies.

In situ formation and spatial variability of particle number concentration in a European megacity

Science.gov (United States)

Pikridas, M.; Sciare, J.; Freutel, F.; Crumeyrolle, S.; von der Weiden-Reinmüller, S.-L.; Borbon, A.; Schwarzenboeck, A.; Merkel, M.; Crippa, M.; Kostenidou, E.; Psichoudaki, M.; Hildebrandt, L.; Engelhart, G. J.; Petäjä, T.; Prévôt, A. S. H.; Drewnick, F.; Baltensperger, U.; Wiedensohler, A.; Kulmala, M.; Beekmann, M.; Pandis, S. N.

2015-09-01

Ambient particle number size distributions were measured in Paris, France, during summer (1-31 July 2009) and winter (15 January to 15 February 2010) at three fixed ground sites and using two mobile laboratories and one airplane. The campaigns were part of the Megacities: Emissions, urban, regional and Global Atmospheric POLlution and climate effects, and Integrated tools for assessment and mitigation (MEGAPOLI) project. New particle formation (NPF) was observed only during summer on approximately 50 % of the campaign days, assisted by the low condensation sink (about 10.7 ± 5.9 × 10-3 s-1). NPF events inside the Paris plume were also observed at 600 m altitude onboard an aircraft simultaneously with regional events identified on the ground. Increased particle number concentrations were measured aloft also outside of the Paris plume at the same altitude, and were attributed to NPF. The Paris plume was identified, based on increased particle number and black carbon concentration, up to 200 km away from the Paris center during summer. The number concentration of particles with diameters exceeding 2.5 nm measured on the surface at the Paris center was on average 6.9 ± 8.7 × 104 and 12.1 ± 8.6 × 104 cm-3 during summer and winter, respectively, and was found to decrease exponentially with distance from Paris. However, further than 30 km from the city center, the particle number concentration at the surface was similar during both campaigns. During summer, one suburban site in the NE was not significantly affected by Paris emissions due to higher background number concentrations, while the particle number concentration at the second suburban site in the SW increased by a factor of 3 when it was downwind of Paris.

Magnetofluidic concentration and separation of non-magnetic particles using two magnet arrays

Science.gov (United States)

Hejazian, Majid

2016-01-01

The present paper reports the use of diluted ferrofluid and two arrays of permanent magnets for the size-selective concentration of non-magnetic particles. The micro magnetofluidic device consists of a straight channels sandwiched between two arrays of permanent magnets. The permanent magnets create multiple capture zones with minimum magnetic field strength along the channel. The complex interaction between magnetic forces and hydrodynamic force allows the device to operate in different regimes suitable for concentration of non-magnetic particles with small difference in size. Our experimental results show that non-magnetic particles with diameters of 3.1 μm and 4.8 μm can be discriminated and separated with this method. The results from this study could be used as a guide for the design of size-sensitive separation devices for particle and cell based on negative magnetophoresis. PMID:27478527

Totally asymmetric exclusion processes with particles of arbitrary size

International Nuclear Information System (INIS)

Lakatos, Greg; Chou, Tom

2003-01-01

The steady-state currents and densities of a one-dimensional totally asymmetric exclusion process (TASEP) with particles that occlude an integer number (d) of lattice sites are computed using various mean-field approximations and Monte Carlo simulations. TASEPs featuring particles of arbitrary size are relevant for modelling systems such as mRNA translation, vesicle locomotion along microtubules and protein sliding along DNA. We conjecture that the nonequilibrium steady-state properties separate into low-density, high-density, and maximal current phases similar to those of the standard (d = 1) TASEP. A simple mean-field approximation for steady-state particle currents and densities is found to be inaccurate. However, we find local equilibrium particle distributions derived from a discrete Tonks gas partition function yield apparently exact currents within the maximal current phase. For the boundary-limited phases, the equilibrium Tonks gas distribution cannot be used to predict currents, phase boundaries, or the order of the phase transitions. However, we employ a refined mean-field approach to find apparently exact expressions for the steady-state currents, boundary densities, and phase diagrams of the d ≥ 1 TASEP. Extensive Monte Carlo simulations are performed to support our analytic, mean-field results

Totally asymmetric exclusion processes with particles of arbitrary size

Energy Technology Data Exchange (ETDEWEB)

Lakatos, Greg; Chou, Tom [Department of Biomathematics and Institute for Pure and Applied Mathematics, UCLA, Los Angeles, CA 90095 (United States)

2003-02-28

The steady-state currents and densities of a one-dimensional totally asymmetric exclusion process (TASEP) with particles that occlude an integer number (d) of lattice sites are computed using various mean-field approximations and Monte Carlo simulations. TASEPs featuring particles of arbitrary size are relevant for modelling systems such as mRNA translation, vesicle locomotion along microtubules and protein sliding along DNA. We conjecture that the nonequilibrium steady-state properties separate into low-density, high-density, and maximal current phases similar to those of the standard (d = 1) TASEP. A simple mean-field approximation for steady-state particle currents and densities is found to be inaccurate. However, we find local equilibrium particle distributions derived from a discrete Tonks gas partition function yield apparently exact currents within the maximal current phase. For the boundary-limited phases, the equilibrium Tonks gas distribution cannot be used to predict currents, phase boundaries, or the order of the phase transitions. However, we employ a refined mean-field approach to find apparently exact expressions for the steady-state currents, boundary densities, and phase diagrams of the d {>=} 1 TASEP. Extensive Monte Carlo simulations are performed to support our analytic, mean-field results.

Fluorescent bioaerosol particle, molecular tracer, and fungal spore concentrations during dry and rainy periods in a semi-arid forest

Directory of Open Access Journals (Sweden)

M. I. Gosselin

2016-12-01

Full Text Available Bioaerosols pose risks to human health and agriculture and may influence the evolution of mixed-phase clouds and the hydrological cycle on local and regional scales. The availability and reliability of methods and data on the abundance and properties of atmospheric bioaerosols, however, are rather limited. Here we analyze and compare data from different real-time ultraviolet laser/light-induced fluorescence (UV-LIF instruments with results from a culture-based spore sampler and offline molecular tracers for airborne fungal spores in a semi-arid forest in the southern Rocky Mountains of Colorado. Commercial UV-APS (ultraviolet aerodynamic particle sizer and WIBS-3 (wideband integrated bioaerosol sensor, version 3 instruments with different excitation and emission wavelengths were utilized to measure fluorescent aerosol particles (FAPs during both dry weather conditions and periods heavily influenced by rain. Seven molecular tracers of bioaerosols were quantified by analysis of total suspended particle (TSP high-volume filter samples using a high-performance anion-exchange chromatography system with pulsed amperometric detection (HPAEC-PAD. From the same measurement campaign, Huffman et al. (2013 previously reported dramatic increases in total and fluorescent particle concentrations during and immediately after rainfall and also showed a strong relationship between the concentrations of FAPs and ice nuclei (Huffman et al., 2013; Prenni et al., 2013. Here we investigate molecular tracers and show that during rainy periods the atmospheric concentrations of arabitol (35.2 ± 10.5 ng m−3 and mannitol (44.9 ± 13.8 ng m−3 were 3–4 times higher than during dry periods. During and after rain, the correlations between FAP and tracer mass concentrations were also significantly improved. Fungal spore number concentrations on the order of 104 m−3, accounting for 2–5 % of TSP mass during dry periods and 17–23 % during rainy

Recovery of infective virus particles in ion-exchange and hydrophobic interaction monolith chromatography is influenced by particle charge and total-to-infective particle ratio.

Science.gov (United States)

Sviben, Dora; Forcic, Dubravko; Ivancic-Jelecki, Jelena; Halassy, Beata; Brgles, Marija

2017-06-01

Viral particles are used in medical applications as vaccines or gene therapy vectors. In order to obtain product of high purity, potency and safety for medical use purification of virus particles is a prerequisite, and chromatography is gaining increased attention to meet this aim. Here, we report on the use of ion-exchange and hydrophobic interaction chromatography on monolithic columns for purification of mumps virus (MuV) and measles virus (MeV). Efficiency of the process was monitored by quantification of infective virus particles (by 50% cell culture infective dose assay) and total virus particles, and monitoring of their size (by Nanoparticle Tracking Analysis). Ion-exchange chromatography was shown to be inefficient for MuV and best results for MeV were obtained on QA column with recovery around 17%. Purification of MuV and MeV by hydrophobic interaction chromatography resulted in recoveries around 60%. Results showed that columns with small channels (d=1.4μm) are not suitable for MuV and MeV, although their size is below 400nm, whereas columns with large channels (6μm) showed to be efficient and recoveries independent on the flow rate up to 10mL/min. Heterogeneity of the virus suspension and its interday variability mostly regarding total-to-infective particle ratio was observed. Interestingly, a trend in recovery depending on the day of the harvest was also observed for both viruses, and it correlated with the total-to-infective particle ratio, indicating influence of the virus sample composition on the chromatography results. Copyright © 2017. Published by Elsevier B.V.

Number concentrations of solid particles from the spinning top aerosol generator

International Nuclear Information System (INIS)

Mitchell, J.P.

1983-02-01

A spinning top aerosol generator has been used to generate monodisperse methylene blue particles in the size range from 0.6 to 6 μm. The number concentrations of these aerosols have been determined by means of an optical particle counter and compared with the equivalent measurements obtained by filter collection and microscopy. (author)

Effect of precursor concentration and spray pyrolysis temperature upon hydroxyapatite particle size and density.

Science.gov (United States)

Cho, Jung Sang; Lee, Jeong-Cheol; Rhee, Sang-Hoon

2016-02-01

In the synthesis of hydroxyapatite powders by spray pyrolysis, control of the particle size was investigated by varying the initial concentration of the precursor solution and the pyrolysis temperature. Calcium phosphate solutions (Ca/P ratio of 1.67) with a range of concentrations from 0.1 to 2.0 mol/L were prepared by dissolving calcium nitrate tetrahydrate and diammonium hydrogen phosphate in deionized water and subsequently adding nitric acid. Hydroxyapatite powders were then synthesized by spray pyrolysis at 900°C and at 1500°C, using these calcium phosphate precursor solutions, under the fixed carrier gas flow rate of 10 L/min. The particle size decreased as the precursor concentration decreased and the spray pyrolysis temperature increased. Sinterability tests conducted at 1100°C for 1 h showed that the smaller and denser the particles were, the higher the relative densities were of sintered hydroxyapatite disks formed from these particles. The practical implication of these results is that highly sinterable small and dense hydroxyapatite particles can be synthesized by means of spray pyrolysis using a low-concentration precursor solution and a high pyrolysis temperature under a fixed carrier gas flow rate. © 2015 Wiley Periodicals, Inc.

Particle Size Affects Concentration-Dependent Cytotoxicity of Chitosan Nanoparticles towards Mouse Hematopoietic Stem Cells

International Nuclear Information System (INIS)

Zaki, S. S. O.; Ibrahim, M. N.; Katas, H.

2015-01-01

Chitosan nanoparticles (CSNPs) have been extensively applied in medical and pharmaceutical fields as promising drug delivery systems. Despite that, the safety of CSNPs remains inadequate and needs further investigation, particularly on hematopoietic stem cells (HSCs). CSNPs were prepared by ionic gelation method and later were characterized for their physical characteristics (particle size and zeta potential). Cytotoxicity of CSNPs was assessed by MTT assay. Particle size was highly influenced by chitosan concentration and molecular weight (medium and high molecular weight (MMW and HMW)). Higher chitosan concentration and molecular weight produced larger nanoparticles. Zeta potential of CSNPs was not significantly affected by chitosan concentrations and molecular weights used in the present study. MMW had a better stability than HMW CSNPs as their particle size and zeta potential were not significantly altered after autoclaving. Cytotoxicity of CSNPs was influenced by zeta potential and particle size. On the other hand, chitosan concentration and molecular weight indirectly influenced cytotoxicity by affecting particle size and zeta potential of CSNPs. In conclusion, cytotoxicity of CSNPs was mainly attributed to their physical characteristics and this opens a strategy to ensure the safety of CSNPs applications in stem cell technology.

Particle number concentration, size distribution and chemical composition during haze and photochemical smog episodes in Shanghai.

Science.gov (United States)

Wang, Xuemei; Chen, Jianmin; Cheng, Tiantao; Zhang, Renyi; Wang, Xinming

2014-09-01

The aerosol number concentration and size distribution as well as size-resolved particle chemical composition were measured during haze and photochemical smog episodes in Shanghai in 2009. The number of haze days accounted for 43%, of which 30% was severe (visibilitysmog episodes, about 5.89 times and 4.29 times those of clean days. The particle volume concentration and surface concentration in haze, photochemical smog and clean days were 102, 49, 15μm(3)/cm(3) and 949, 649, 206μm(2)/cm(3), respectively. As haze events got more severe, the number concentration of particles smaller than 50nm decreased, but the particles of 50-200nm and 0.5-1μm increased. The diurnal variation of particle number concentration showed a bimodal pattern in haze days. All soluble ions were increased during haze events, of which NH4(+), SO4(2-) and NO3(-) increased greatly, followed by Na(+), K(+), Ca(2+) and Cl(-). These ions were very different in size-resolved particles during haze and photochemical smog episodes. Copyright © 2014. Published by Elsevier B.V.

Variability of sub-micrometer particle number size distributions and concentrations in the Western Mediterranean regional background

Directory of Open Access Journals (Sweden)

Michael Cusack

2013-02-01

Full Text Available This study focuses on the daily and seasonal variability of particle number size distributions and concentrations, performed at the Montseny (MSY regional background station in the western Mediterranean from October 2010 to June 2011. Particle number concentrations at MSY were shown to be within range of various other sites across Europe reported in literature, but the seasonality of the particle number size distributions revealed significant differences. The Aitken mode is the dominant particle mode at MSY, with arithmetic mean concentrations of 1698 cm3, followed by the accumulation mode (877 cm−3 and the nucleation mode (246 cm−3. Concentrations showed a strong seasonal variability with large increases in particle number concentrations observed from the colder to warmer months. The modality of median size distributions was typically bimodal, except under polluted conditions when the size distribution was unimodal. During the colder months, the daily variation of particle number size distributions are strongly influenced by a diurnal breeze system, whereby the Aitken and accumulation modes vary similarly to PM1 and BC mass concentrations, with nocturnal minima and sharp day-time increases owing to the development of a diurnal mountain breeze. Under clean air conditions, high levels of nucleation and lower Aitken mode concentrations were measured, highlighting the importance of new particle formation as a source of particles in the absence of a significant condensation sink. During the warmer months, nucleation mode concentrations were observed to be relatively elevated both under polluted and clean conditions due to increased photochemical reactions, with enhanced subsequent growth owing to elevated concentrations of condensable organic vapours produced from biogenic volatile organic compounds, indicating that nucleation at MSY does not exclusively occur under clean air conditions. Finally, mixing of air masses between polluted and non

Outdoor ultrafine particle concentrations in front of fast food restaurants.

Science.gov (United States)

Vert, Cristina; Meliefste, Kees; Hoek, Gerard

2016-01-01

Ultrafine particles (UFPs) have been associated with negative effects on human health. Emissions from motor vehicles are the principal source of UFPs in urban air. A study in Vancouver suggested that UFP concentrations were related to density of fast food restaurants near the monitoring sites. A previous monitoring campaign could not separate the contribution of restaurants from road traffic. The main goal of this study has been the quantification of fast food restaurants' contribution to outdoor UFP concentrations. A portable particle number counter (DiscMini) has been used to carry out mobile monitoring in a largely pedestrianized area in the city center of Utrecht. A fixed route passing 17 fast food restaurants was followed on 8 days. UFP concentrations in front of the restaurants were 1.61 times higher than in a nearby square without any local sources used as control area and 1.22 times higher compared with all measurements conducted in between the restaurants. Adjustment for other sources such as passing mopeds, smokers or candles did not explain the increase. In conclusion, fast food restaurants result in significant increases in outdoor UFP concentrations in front of the restaurant.

Effects of concentrated ambient particles on normal and hypersecretory airways in rats.

Science.gov (United States)

Harkema, Jack R; Keeler, Gerald; Wagner, James; Morishita, Masako; Timm, Edward; Hotchkiss, Jon; Marsik, Frank; Dvonch, Timothy; Kaminski, Norbert; Barr, Edward

2004-08-01

protocol, PM2.5 trace elements of anthropogenic origin (La, V, and S) were recovered from the lung tissues of CAPs-exposed rats. Recovery of these specific trace elements was greatest in rats with OVA-induced allergic airway disease. Additional laboratory experiments using intratracheal instillations of ambient PM2.5 samples were performed to identify bioactive agents in the CAPs to which rats had been exposed in the inhalation exposure component. Because the most pronounced effects of CAPs inhalation were found in BN rats with OVA-induced allergic airways exposed in September, we used ambient PM2.5 samples that were collected on 2 days during the September CAPs inhalation exposures to use for instillation. Ambient PM2.5 samples were collected, fractionated into soluble and insoluble species, and then compared with each other and with total PM2.5 for their effects in healthy BN rats and those with OVA-induced allergic airway disease. Intratracheal instillation of the insoluble fraction of PM2.5 caused mild neutrophilic inflammation in the lungs of healthy rats. However, total PM2.5 or the soluble or insoluble fractions instilled in rats with OVA-induced airway inflammation did not enhance the inflammation or the airway epithelial remodeling that was evident in some of the BN rats exposed to CAPs by inhalation. Therefore, the results from this instillation component did not suggest what fractions of the CAPs may have been responsible for enhancing OVA-induced airway mucosubstances and pulmonary inflammation observed in the inhalation exposure component. In summary, inhaled CAPs-related pulmonary alterations in the affected OVA-challenged rats appeared to be related to the chemical composition, rather than the mass concentration, to which the animals were exposed. Results of the trace element analysis in the lungs of CAPs-exposed BN rats exposed in September suggested that air particles derived from identified local combustion sources were preferentially retained in allergic

Optical sensor technology for simultaneous measurement of particle speed and concentration of micro sized particles

DEFF Research Database (Denmark)

Clausen, Casper; Han, Anpan; Kristensen, Martin

2013-01-01

Experimental characterization of a sensor technology that can measure particle speed and concentration simultaneously in liquids and gases is presented here. The basic sensor principle is based on an optical element that shapes a light beam into well-defined fringes. The technology can be described...

Determination of particles concentration in Black Sea waters from spectral beam attenuation coefficient

Science.gov (United States)

Korchemkina, E. N.; Latushkin, A. A.; Lee, M. E.

2017-11-01

The methods of determination of concentration and scattering by suspended particles in seawater are compared. The methods considered include gravimetric measurements of the mass concentration of suspended matter, empirical and analytical calculations based on measurements of the light beam attenuation coefficient (BAC) in 4 spectral bands, calculation of backscattering by particles using satellite measurements in the visible spectral range. The data were obtained in two cruises of the R/V "Professor Vodyanitsky" in the deep-water part of the Black Sea in July and October 2016., Spatial distribution of scattering by marine particles according to satellite data is in good agreement with the contact measurements.

Estimation of inhaled airborne particle number concentration by subway users in Seoul, Korea.

Science.gov (United States)

Kim, Minhae; Park, Sechan; Namgung, Hyeong-Gyu; Kwon, Soon-Bark

2017-12-01

Exposure to airborne particulate matter (PM) causes several diseases in the human body. The smaller particles, which have relatively large surface areas, are actually more harmful to the human body since they can penetrate deeper parts of the lungs or become secondary pollutants by bonding with other atmospheric pollutants, such as nitrogen oxides. The purpose of this study is to present the number of PM inhaled by subway users as a possible reference material for any analysis of the hazards to the human body arising from the inhalation of such PM. Two transfer stations in Seoul, Korea, which have the greatest number of users, were selected for this study. For 0.3-0.422 μm PM, particle number concentration (PNC) was highest outdoors but decreased as the tester moved deeper underground. On the other hand, the PNC between 1 and 10 μm increased as the tester moved deeper underground and showed a high number concentration inside the subway train as well. An analysis of the particles to which subway users are actually exposed to (inhaled particle number), using particle concentration at each measurement location, the average inhalation rate of an adult, and the average stay time at each location, all showed that particles sized 0.01-0.422 μm are mostly inhaled from the outdoor air whereas particles sized 1-10 μm are inhaled as the passengers move deeper underground. Based on these findings, we expect that the inhaled particle number of subway users can be used as reference data for an evaluation of the hazards to health caused by PM inhalation. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Comparison of in vivo characteristics of polyethylene wear particles produced by a metal and a ceramic femoral component in total knee replacement].

Science.gov (United States)

Veigl, D; Vavřík, P; Pokorný, D; Slouf, M; Pavlova, E; Landor, I

2011-01-01

The aim of the study was to evaluate in vivo and compare, in terms of the quality and number of ultra high-molecular polyethylene (UHMWPE) wear particles, total knee replacements of identical construction differing only in the material used for femoral component production, i.e., CoCrMo alloy or ZrO2 ceramics. Samples of peri-prosthetic granuloma tissue were collected in two patients with total knee replacement suffering from implant migration, who were matched in relevant characteristics. The primary knee replacement in Patient 1 with a CoCrMo femoral component was done 7.2 years and in Patient 2 with a ZrO2 implant 6.8 years before this assessment. The polyethylene wear-induced granuloma was analysed by the MORF method enabling us to assess the shape and size of wear debris and the IRc method for assessment of particle concentration. In the granuloma tissue samples of Patient 1, on the average, particles were 0.30 mm in size and their relative volume was 0.19. In the Patient 2 tissue samples, the average size of particles was 0.33 mm and their relative volume was 0.26. There was no significant difference in either particle morphology or their concentration in the granuloma tissue between the two patients. One of the options of how to reduce the production of polyethylene wear particles is to improve the tribological properties of contacting surfaces in total knee replacement by substituting a cobalt-chrome femoral component with a zirconia ceramic femoral component. The previous in vitro testing carried out with a mechanical simulator under conditions approaching real weight-bearing in the human body did show a nearly three-fold decrease in the number of UHMWPE wear particles in zirconia components. The evaluation of granuloma tissue induced by the activity of a real prosthetic joint for nearly seven years, however, did not reveal any great difference in either quality or quantity of polyethylene debris between the two replacements. The difference of surface

The Biologic Response to Polyetheretherketone (PEEK) Wear Particles in Total Joint Replacement: A Systematic Review.

Science.gov (United States)

Stratton-Powell, Ashley A; Pasko, Kinga M; Brockett, Claire L; Tipper, Joanne L

2016-11-01

Polyetheretherketone (PEEK) and its composites are polymers resistant to fatigue strain, radiologically transparent, and have mechanical properties suitable for a range of orthopaedic applications. In bulk form, PEEK composites are generally accepted as biocompatible. In particulate form, however, the biologic response relevant to joint replacement devices remains unclear. The biologic response to wear particles affects the longevity of total joint arthroplasties. Particles in the phagocytozable size range of 0.1 µm to 10 µm are considered the most biologically reactive, particularly particles with a mean size of PEEK-based wear debris from total joint arthroplasties. (1) What are the quantitative characteristics of PEEK-based wear particles produced by total joint arthroplasties? (2) Do PEEK wear particles cause an adverse biologic response when compared with UHMWPE or a similar negative control biomaterial? (3) Is the biologic response affected by particle characteristics? Embase and Ovid Medline databases were searched for studies that quantified PEEK-based particle characteristics and/or investigated the biologic response to PEEK-based particles relevant to total joint arthroplasties. The keyword search included brands of PEEK (eg, MITCH, MOTIS) or variations of PEEK types and nomenclature (eg, PAEK, CFR-PEEK) in combination with types of joint (eg, hip, knee) and synonyms for wear debris or immunologic response (eg, particles, cytotoxicity). Peer-reviewed studies, published in English, investigating total joint arthroplasty devices and cytotoxic effects of PEEK particulates were included. Studies investigating devices without articulating bearings (eg, spinal instrumentation devices) and bulk material or contact cytotoxicity were excluded. Of 129 studies, 15 were selected for analysis and interpretation. No studies were found that isolated and characterized PEEK wear particles from retrieved periprosthetic human tissue samples. In the four studies that

Concentrations and size distributions of fine aerosol particles measured at roof level in urban zone

Science.gov (United States)

Despiau, S.; Croci, D.

2007-05-01

During the experimental Field Experiments to Constrain Models of Atmospheric Pollution and Transport of Emissions (ESCOMPTE) campaign in June-July 2001, concentrations and size distributions of fine particles (14-722 nm) were measured at roof level in downtown Marseille (France). Part of the campaign was dedicated to the study of aerosol behavior in relation to strong photochemical events (which were identified as "IOP" days) and their regional modeling. The analysis of the concentration variations and the evolution of average diurnal size distribution showed that an "IOP day" is not characterized by a specific concentration or its variation, nor by a specific evolution of the average size distribution. The morning traffic rush is detected at roof level by a net increase in particle concentration over the whole size range measured, indicating a production of ultrafine particles by the traffic but also the raising to roof level of particles of the accumulation mode. The increase is observed about 1 hour after the traffic peak at street level, which is characterized by strong increases in NOx and CO concentrations. The corresponding flux of particles at roof level has been estimated around 3 × 104 cm-2 s-1. A specific signature characterized by a strong and rapid burst of concentration (factor 2 to 4 in 15 min) of particles between 25 and 50 nm, independent of the traffic source, has been detected on six occasions during the campaign. These events occur systematically around noon, in cases of strong radiation, low relative humidity, and common wind direction. Despite the high-diameter value of these particles, it is suggested that they could result from a specific "secondary aerosol process" event involving ozone, biogenic, and/or anthropogenic gas precursors like iodine and VOCs.

Decreasing particle number concentrations in a warming atmosphere and implications

Directory of Open Access Journals (Sweden)

F. Yu

2012-03-01

Full Text Available New particle formation contributes significantly to the number concentration of condensation nuclei (CN as well as cloud CN (CCN, a key factor determining aerosol indirect radiative forcing of the climate system. Using a physics-based nucleation mechanism that is consistent with a range of field observations of aerosol formation, it is shown that projected increases in global temperatures could significantly inhibit new particle, and CCN, formation rates worldwide. An analysis of CN concentrations observed at four NOAA ESRL/GMD baseline stations since the 1970s and two other sites since 1990s reveals long-term decreasing trends that are consistent in sign with, but are larger in magnitude than, the predicted temperature effects. The possible reasons for larger observed long-term CN reductions at remote sites are discussed. The combined effects of rising temperatures on aerosol nucleation rates and other chemical and microphysical processes may imply substantial decreases in future tropospheric particle abundances associated with global warming, delineating a potentially significant feedback mechanism that increases Earth's climate sensitivity to greenhouse gas emissions. Further research is needed to quantify the magnitude of such a feedback process.

Aerosol trace metals, particle morphology and total gaseous mercury in the atmosphere of Oxford, UK

Science.gov (United States)

Witt, M. L. I.; Meheran, N.; Mather, T. A.; de Hoog, J. C. M.; Pyle, D. M.

2010-04-01

An investigation of atmospheric trace metals was conducted in Oxford, UK, a small city ˜60 miles northwest of London, in 2007 and 2008. Concentrations of Sr, Mo, Cd, Pb, V, Cr, Mn, Fe, Co, Ni, Cu and Zn in aerosol were measured in bulk and size segregated samples. In addition, total gaseous mercury (TGM) concentrations were monitored semi-continuously by cold vapour-atomic fluorescence spectroscopy. Metal concentrations in Oxford were intermediate between previously reported levels of UK rural and urban areas for most metals studied and levels of Cd, Ni and Pb were within European guidelines. Metal concentrations appeared to be influenced by higher traffic volume on a timescale of hours. The influence of traffic on the aerosols was also suggested by the observation of carbonaceous particles via scanning electron microscopy (SEM). Air mass back trajectories suggest air masses arriving in Oxford from London and mainland Europe contained the highest metal concentrations. Aerosol samples collected over Bonfire Weekend, a period of intense firework use and lighting of bonfires in the UK, showed metal concentrations 6-46 times higher than at other times. Strontium, a tracer of firework release, was present at higher concentrations and showed a change in its size distribution from the coarse to fine mode over Bonfire Weekend. The presence of an abundance of spherical Sr particles was also confirmed in SEM images. The average TGM concentration in Oxford was 3.17 ng m -3 (st. dev. 1.59) with values recorded between 1.32 and 23.2 ng m -3. This is a higher average value than reported from nearby rural locations, although during periods when air was arriving from the west, similar concentrations to these rural areas were seen in Oxford. Comparison to meteorological data suggests that TGM in Oxford's air is highest when wind is arriving from the east/southeast. This may be due to emissions from London/mainland Europe with a possible contribution from emissions from a local

Reduced Ultrafine Particle Concentration in Urban Air: Changes in Nucleation and Anthropogenic Emissions.

Science.gov (United States)

Saha, Provat K; Robinson, Ellis S; Shah, Rishabh U; Zimmerman, Naomi; Apte, Joshua S; Robinson, Allen L; Presto, Albert A

2018-06-19

Nucleation is an important source of ambient ultrafine particles (UFP). We present observational evidence of the changes in the frequency and intensity of nucleation events in urban air by analyzing long-term particle size distribution measurements at an urban background site in Pittsburgh, Pennsylvania during 2001-2002 and 2016-2017. We find that both frequency and intensity of nucleation events have been reduced by 40-50% over the past 15 years, resulting in a 70% reduction in UFP concentrations from nucleation. On average, the particle growth rates are 30% slower than 15 years ago. We attribute these changes to dramatic reductions in SO 2 (more than 90%) and other pollutant concentrations. Overall, UFP concentrations in Pittsburgh have been reduced by ∼48% in the past 15 years, with a ∼70% reduction in nucleation, ∼27% in weekday local sources (e.g., weekday traffic), and 49% in the regional background. Our results highlight that a reduction in anthropogenic emissions can considerably reduce nucleation events and UFP concentrations in a polluted urban environment.

Airborne particulate concentrations and fluxes at an active uranium mill tailings site

International Nuclear Information System (INIS)

Sehmel, G.A.

1978-01-01

Direct measurements of airborne particulate concentrations and fluxes of transported mill tailing materials were measured at an active mill tailings site. Experimental measurement equipment consisted of meteorological instrumentation to automatically activate total particulate air samplers as a function of wind speed increments and direction, as well as particle cascade impactors to measure airborne respirable concentrations as a function of particle size. In addition, an inertial impaction device measured nonrespirable fluxes of airborne particles. Caclulated results are presented in terms of the airborne solid concentration in g/m 3 , the horizontal airborne mass flux in g/(m 2 -day) for total collected nonrespirable particles and the radionuclide concentrations in dpm/g as a function of particle diameter for respirable and nonrespirable particles

Summer–winter concentrations and gas-particle partitioning of short chain chlorinated paraffins in the atmosphere of an urban setting

International Nuclear Information System (INIS)

Wang Thanh; Han Shanlong; Yuan Bo; Zeng Lixi; Li Yingming; Wang Yawei; Jiang Guibin

2012-01-01

Short chain chlorinated paraffins (SCCPs) are semi-volatile chemicals that are considered persistent in the environment, potential toxic and subject to long-range transport. This study investigates the concentrations and gas-particle partitioning of SCCPs at an urban site in Beijing during summer and wintertime. The total atmospheric SCCP levels ranged 1.9–33.0 ng/m 3 during wintertime. Significantly higher levels were found during the summer (range 112–332 ng/m 3 ). The average fraction of total SCCPs in the particle phase (φ) was 0.67 during wintertime but decreased significantly during the summer (φ = 0.06). The ten and eleven carbon chain homologues with five to eight chlorine atoms were the predominant SCCP formula groups in air. Significant linear correlations were found between the gas-particle partition coefficients and the predicted subcooled vapor pressures and octanol–air partition coefficients. The gas-particle partitioning of SCCPs was further investigated and compared with both the Junge–Pankow adsorption and K oa -based absorption models. - Highlights: ► Short chain chlorinated paraffins were investigated in air samples from Beijing. ► Higher levels of SCCPs were found in air during summertime than wintertime. ► Relevant physical–chemical properties were estimated by SPARC and EPI Suite. ► Obtained data were used to model the gas-particle partitioning of SCCPs. - Atmospheric levels and gas-particle partitioning of SCCPs in Beijing, China.

Age-dependent changes in the total protein concentrations in the ...

African Journals Online (AJOL)

related changes in total protein concentrations in ten regions of the pig brain and hypophyses from birth to 36 months of age. Age-related changes in protein concentrations in all the brain regions except the pons and cerebral cortex were not ...

Vertical profiles of black carbon concentration and particle number size distribution in the North China Plain

Science.gov (United States)

Ran, L.; Deng, Z.

2013-12-01

The vertical distribution of aerosols is of great importance to our understanding in the impacts of aerosols on radiation balance and climate, as well as air quality and public health. To better understand and estimate the effects of atmospheric components including trace gases and aerosols on atmospheric environment and climate, an intensive field campaign, Vertical Observations of trace Gases and Aerosols in the North China Plain (VOGA-NCP), was carried out from late July to early August 2013 over a rural site in the polluted NCP. During the campaign, vertical profiles of black carbon (BC) concentration and particle number size distribution were measured respectively by a micro-Aethalometer and an optical particle counter attached to a tethered balloon within 1000 m height. Meteorological parameters, including temperature, relative humidity, wind speed and wind direction, were measured simultaneously by a radiosonde also attached to the tethered balloon. Preliminary results showed distinct diurnal variations of the vertical distribution of aerosol total number concentration and BC concentration, following the development of the mixing layer. Generally, there was a well mixing of aerosols within the mixing layer and a sharp decrease above the mixing layer. Particularly, a small peak of BC concentrations was observed around 400-500 m height for several profiles. Further analysis would be needed to explain such phenomenon. It was also found that measured vertical profiles of BC using the filter-based method might be affected by the vertical distribution of relative humidity.

Free amino nitrogen concentration correlates to total yeast assimilable nitrogen concentration in apple juice.

Science.gov (United States)

Boudreau, Thomas F; Peck, Gregory M; O'Keefe, Sean F; Stewart, Amanda C

2018-01-01

Yeast assimilable nitrogen (YAN) is essential for yeast growth and metabolism during apple ( Malus x domestica Borkh.) cider fermentation. YAN concentration and composition can impact cider fermentation kinetics and the formation of volatile aroma compounds by yeast. The YAN concentration and composition of apples grown in Virginia, USA over the course of two seasons was determined through analysis of both free amino nitrogen (FAN) and ammonium ion concentration. FAN was the largest fraction of YAN, with a mean value of 51 mg N L -1 FAN compared to 9 mg N L -1 ammonium. Observed YAN values ranged from nine to 249 mg N L -1 , with a mean value of 59 mg N L -1 . Ninety-four percent of all samples analyzed in this study contained yeast to fully utilize all of the fermentable sugars. FAN concentration was correlated with total YAN concentration, but ammonium concentration was not. Likewise, there was no correlation between FAN and ammonium concentration.

Concentration Measurements of Suspended Load using ADV with Influence of the Particle Size

Science.gov (United States)

Schwarzwälder, Kordula

2017-04-01

ADV backscatter data can be used under certain conditions to gain information about the concentrations of suspended loads. This was shown in many studies before (Fugate and Friedrichs 2002; Chanson et al 2008; Ha et al. 2009). This paper reports on a pre-study to investigate the influence of particle size on concentration measurements for suspended sediment load with ADV. The study was conducted in a flume in the Oskar-von-Miller-Institute using fresh water from a river including the natural suspended load. The ADV used in the experiments was a Vectrino Profiler (Nortek). In addition water samples were taken for TSS and TOC. For the measurements a surge was generated in the flume to ensure that also particles of larger size will be present in the water phase. The measurements and samples were taken during the whole surge event. Therefore we were able to find a good correlation between the backscatter data of the ADV and the TSS as well as TOC results. For the decreasing part of the flow event the concentration of TOC in the suspended load of the water phase is decreasing much slower than the TSS and results in a damped decrease of the backscatter values. This means that the results for concentration measurements might be slightly influenced by the size of the particles. Further evaluations of measurements conducted with a LISST SL (Sequoia) will be investigated to show the trend of the particle sizes during this process and fortify this result. David C. Fugate, Carl T. Friedrichs, Determining concentration and fall velocity of estuarine particle populations using ADV, OBS and LISST, Continental Shelf Research, Volume 22, Issues 11-13, 2002 H.K. Ha, W.-Y. Hsu, J.P.-Y. Maa, Y.Y. Shao, C.W. Holland, Using ADV backscatter strength for measuring suspended cohesive sediment concentration, Continental Shelf Research, Volume 29, Issue 10, 2009 Hubert Chanson, Maiko Takeuchi, Mark Trevethan, Using turbidity and acoustic backscatter intensity as surrogate measures of

Atherogenic lipoprotein particle size and concentrations and the effect of pravastatin in children with familial hypercholesterolemia

NARCIS (Netherlands)

van der Graaf, Anouk; Rodenburg, Jessica; Vissers, Maud N.; Hutten, Barbara A.; Wiegman, Albert; Trip, Mieke D.; Stroes, Erik S. G.; Wijburg, Frits A.; Otvos, James D.; Kastelein, John J. P.

2008-01-01

OBJECTIVE: To determine lipoprotein particle concentrations and size in children with familial hypercholesterolemia (FH) and investigate the effect of pravastatin therapy on these measures. STUDY DESIGN: Lipoprotein particle concentrations and sizes were examined by nuclear magnetic resonance (NMR)

Total mercury concentration in common fish species of Lake Victoria ...

African Journals Online (AJOL)

Total mercury (THg) concentration was analysed in muscles of common fish species of Lake Victoria in the eastern and southern parts of the lake using cold vapour Atomic Absorption Spectrophotometric technique. Mercury concentration in all fish species was generally lower than the WHO maximum allowable ...

Suspended particle and drug ingredient concentrations in hospital dispensaries and implications for pharmacists' working environments.

Science.gov (United States)

Inaba, Ryoichi; Hioki, Atsushi; Kondo, Yoshihiro; Nakamura, Hiroki; Nakamura, Mitsuhiro

2016-03-01

The aim of this study was to assess the present status of working environments for pharmacists, including the concentrations of suspended particles and suspended drug ingredients in dispensaries. We conducted a survey on the work processes and working environment in 15 hospital dispensaries, and measured the concentrations of suspended particles and suspended drug ingredients using digital dust counter and high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS), respectively. Of 25 types of powdered drugs that were frequently handled in the 15 dispensaries surveyed, 11 could be quantitatively determined. The amounts of suspended particles were relatively high, but below the reference value, in three dispensaries without dust collectors. The sedative-hypnotic drug zopiclone was detected in the suspended particles at one dispensary that was not equipped with dust collectors, and the antipyretic and analgesic drug acetaminophen was detected in two dispensaries equipped with dust collectors. There was no correlation between the daily number of prescriptions containing powdered drugs and the concentration of suspended particles in dispensaries. On the basis of the suspended particle concentrations measured, we concluded that dust collectors were effective in these dispensaries. However, suspended drug ingredients were detected also in dispensaries with dust collectors. These results suggest that the drug dust control systems of individual dispensaries should be properly installed and managed.

Organic Nitrogen in Atmospheric Drops and Particles: Concentrations, (Limited) Speciation, and Chemical Transformations

Science.gov (United States)

Anastasio, C.; Zhang, Q.

2003-12-01

While quite a bit is known of the concentrations, speciation, and chemistry of inorganic forms of nitrogen in the atmosphere, the same cannot be said for organic forms. Despite this, there is growing evidence that organic N (ON) is ubiquitous in the atmosphere, especially in atmospheric condensed phases such as fog/cloud drops and aerosol particles. Although the major compounds that make up organic N are generally unknown, as are the sources of these compounds, it is clear that there are significant fluxes of ON between the atmosphere and ecosystems. It also appears that organic N can have significant effects in both spheres. The goal of our recent work in this area has been to better describe the atmospheric component of the biogeochemistry of organic nitrogen. Based on particle, gas, and fogwater samples from Northern California we have made three major findings: 1) Organic N represents a significant component, approximately 20%, of the total atmospheric N loading in these samples. This is broadly consistent with studies from other locations. 2) Amino compounds, primarily as combined amino acids, account for approximately 20% of the measured ON in our condensed phase samples. Given the properties of amino acids, these compounds could significantly affect the chemical and physical properties of atmospheric particles. 3) Organic nitrogen in atmospheric particles and drops is transformed to inorganic forms - primarily ammonium, nitrate, and nitrogen oxides (NOx) - during exposure to sunlight and/or ozone. These chemical reactions likely increase the bioavailability of the condensed phase nitrogen pool and enhance its biological effects after deposition to ecosystems.

Exchange of reactive nitrogen compounds: concentrations and fluxes of total ammonium and total nitrate above a spruce canopy

Directory of Open Access Journals (Sweden)

V. Wolff

2010-05-01

Full Text Available Total ammonium (tot-NH₄⁺ and total nitrate (tot-NO₃⁻ provide chemically conservative quantities in the measurement of surface exchange of reactive nitrogen compounds ammonia (NH₃, particulate ammonium (NH₄⁺, nitric acid (HNO₃, and particulate nitrate (NO₃⁻, using the aerodynamic gradient method. Total fluxes were derived from concentration differences of total ammonium (NH₃ and NH₄⁺ and total nitrate (HNO₃ and NO₃⁻ measured at two levels. Gaseous species and related particulate compounds were measured selectively, simultaneously and continuously above a spruce forest canopy in south-eastern Germany in summer 2007. Measurements were performed using a wet-chemical two-point gradient instrument, the GRAEGOR. Median concentrations of NH₃, HNO₃, NH₄⁺, and NO₃⁻ were 0.57, 0.12, 0.76, and 0.48 μg m⁻³, respectively. Total ammonium and total nitrate fluxes showed large variations depending on meteorological conditions, with concentrations close to zero under humid and cool conditions and higher concentrations under dry conditions. Mean fluxes of total ammonium and total nitrate in September 2007 were directed towards the forest canopy and were −65.77 ng m⁻² s⁻¹ and −41.02 ng m⁻² s⁻¹ (in terms of nitrogen, respectively. Their deposition was controlled by aerodynamic resistances only, with very little influence of surface resistances. Including measurements of wet deposition and findings of former studies on occult deposition (fog water interception at the study site, the total N deposition in September 2007 was estimated to 5.86 kg ha⁻¹.

Measurement of airborne concentrations of radon-220 daughter products by alpha-particle spectrometry

International Nuclear Information System (INIS)

Kerr, G.D.; Ryan, M.T.; Perdue, P.T.

1978-01-01

The decay of naturally occurring uranium-238 and thorium-232 produces radon-222 and radon-220 isotopes which can escape into the atmosphere. If these radon gases become concentrated in air, their daughter products may present an inhalation hazard to man. The airborne concentrations of radon-222 can usually be measured very accurately in the presence of normal airborne concentrations of radon-220 and its daughters. In contrast, the measurements of the airborne concentrations of radon-220 daughters are usually complicated by the presence of radon-222 and its daughters even at normally occurring airborne concentrations. The complications involved in these measurements can be overcome in most situations by using an alpha particle spectrometer to distinguish the activity of radon-222 daughters from that due to radon-220 daughters collected on a filter. A practical spectrometer for field measurements of alpha particle activity on a filter is discussed

Preliminary evaluation of serum total cholesterol concentrations in dogs with osteosarcoma.

Science.gov (United States)

Leeper, H; Viall, A; Ruaux, C; Bracha, S

2017-10-01

To determine if total serum cholesterol concentrations were altered in dogs with osteosarcoma. To evaluate association of total serum cholesterol concentration with clinical outcomes in dogs with appendicular osteosarcoma. Retrospective, multi-institutional study on 64 dogs with osteosarcoma. Control population consisted of dogs with traumatic bone fractures (n=30) and healthy patients of similar age and weight as those of the osteosarcoma cases (n=31). Survival analysis was done on 35 appendicular osteosarcoma patients that received the current standard of care. Statistical associations were assessed by univariable and multi-variable analysis. Information about age, sex, primary tumour location, total cholesterol concentration, monocytes and lymphocyte counts and alkaline phosphatase were also included. Total cholesterol was elevated above the reference interval (3·89 to 7·12 mmol/L) (150 to 275 mg/dL) in 29 of 64 (45·3%) osteosarcoma-bearing dogs, whereas similar elevations were found in only 3 of 30 (10%) fracture controls (Posteosarcoma. These results suggest that elevated total cholesterol is associated with canine osteosarcoma and may have prognostic significance. © 2017 British Small Animal Veterinary Association.

Multi-step process for concentrating magnetic particles in waste sludges

Science.gov (United States)

Watson, John L.

1990-01-01

This invention involves a multi-step, multi-force process for dewatering sludges which have high concentrations of magnetic particles, such as waste sludges generated during steelmaking. This series of processing steps involves (1) mixing a chemical flocculating agent with the sludge; (2) allowing the particles to aggregate under non-turbulent conditions; (3) subjecting the mixture to a magnetic field which will pull the magnetic aggregates in a selected direction, causing them to form a compacted sludge; (4) preferably, decanting the clarified liquid from the compacted sludge; and (5) using filtration to convert the compacted sludge into a cake having a very high solids content. Steps 2 and 3 should be performed simultaneously. This reduces the treatment time and increases the extent of flocculation and the effectiveness of the process. As partially formed aggregates with active flocculating groups are pulled through the mixture by the magnetic field, they will contact other particles and form larger aggregates. This process can increase the solids concentration of steelmaking sludges in an efficient and economic manner, thereby accomplishing either of two goals: (a) it can convert hazardous wastes into economic resources for recycling as furnace feed material, or (b) it can dramatically reduce the volume of waste material which must be disposed.

The effects of fluvial transport on radionuclide concentrations on different particle size classes

International Nuclear Information System (INIS)

Dyer, F.J.; Olley, J.M.

1998-01-01

This paper reports on the effects of grain abrasion and disaggregation on the distribution of 137 Cs with respect to particle size and the effects this may have on the use of 137 Cs for determining the origin of recent sediment. Cs-137 is a product of above ground nuclear testing and has been deposited on the earth's surface by rainfall. On contact with soil, 137 Cs is strongly adsorbed by soil particles and there is a direct correlation between 137 Cs concentration and decreasing particle size. Rapid adsorption means that 137 Cs is preferentially concentrated in surface soils, and it's subsequent redistribution by physical processes rather than chemical has lead to 137 Cs being widely used to study soil erosion

Single particle transfer for quantitative analysis with total-reflection X-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Esaka, Fumitaka; Esaka, Konomi T.; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu; Watanabe, Kazuo

2006-01-01

The technique of single particle transfer was applied to quantitative analysis with total-reflection X-ray fluorescence (TXRF) spectrometry. The technique was evaluated by performing quantitative analysis of individual Cu particles with diameters between 3.9 and 13.2 μm. The direct quantitative analysis of the Cu particle transferred onto a Si carrier gave a discrepancy between measured and calculated Cu amounts due to the absorption effects of incident and fluorescent X-rays within the particle. By the correction for the absorption effects, the Cu amounts in individual particles could be determined with the deviation within 10.5%. When the Cu particles were dissolved with HNO 3 solution prior to the TXRF analysis, the deviation was improved to be within 3.8%. In this case, no correction for the absorption effects was needed for quantification

Outdoor ultrafine particle concentrations in front of fast food restaurants

NARCIS (Netherlands)

Vert, Cristina; Meliefste, Kees; Hoek, Gerard

2016-01-01

Ultrafine particles (UFPs) have been associated with negative effects on human health. Emissions from motor vehicles are the principal source of UFPs in urban air. A study in Vancouver suggested that UFP concentrations were related to density of fast food restaurants near the monitoring sites. A

Increased ultrafine particles and carbon monoxide concentrations are associated with asthma exacerbation among urban children

Science.gov (United States)

Evans, Kristin A.; Halterman, Jill S.; Hopke, Philip K.; Fagnano, Maria; Rich, David Q.

2014-01-01

Objectives Increased air pollutant concentrations have been linked to several asthma-related outcomes in children, including respiratory symptoms, medication use, and hospital visits. However, few studies have examined effects of ultrafine particles in a pediatric population. Our primary objective was to examine the effects of ambient concentrations of ultrafine particles on asthma exacerbation among urban children and determine whether consistent treatment with inhaled corticosteroids could attenuate these effects. We also explored the relationship between asthma exacerbation and ambient concentrations of accumulation mode particles, fine particles (≤ 2.5 micrograms [μm]; PM2.5), carbon monoxide, sulfur dioxide, and ozone. We hypothesized that increased 1 to 7 day concentrations of ultrafine particles and other pollutants would be associated with increases in the relative odds of an asthma exacerbation, but that this increase in risk would be attenuated among children receiving school-based corticosteroid therapy. Methods We conducted a pilot study using data from 3–10 year-old children participating in the School-Based Asthma Therapy trial. Using a time-stratified case-crossover design and conditional logistic regression, we estimated the relative odds of a pediatric asthma visit treated with prednisone (n=96 visits among 74 children) associated with increased pollutant concentrations in the previous 7 days. We re-ran these analyses separately for children receiving medications through the school-based intervention and children in a usual care control group. Results Interquartile range increases in ultrafine particles and carbon monoxide concentrations in the previous 7 days were associated with increases in the relative odds of a pediatric asthma visit, with the largest increases observed for 4-day mean ultrafine particles (interquartile range=2088 p/cm3; OR=1.27; 95% CI=0.90–1.79) and 7-day mean carbon monoxide (interquartile range=0.17 ppm; OR=1.63; 95

Correlation of Air Quality Data to Ultrafine Particles (UFP Concentration and Size Distribution in Ambient Air

Directory of Open Access Journals (Sweden)

Werner Hofmann

2010-07-01

Full Text Available This study monitored ultrafine particles (UFP concurrent with environmental air quality data, investigating whether already existing instrumentation used by environmental authorities can provide reference values for estimating UFP concentrations. Of particular interest was the relation of UFP to PM10 (particulate matter and nitrogen oxides (NOx, NO2 in ambient air. Existing PM measurement methods alone did not correspond exactly enough with the actual particle number, but we observed a link between NOx and NO2 to UFP concentration. The combined data could act as proxy-indicator for authorities in estimating particle number concentrations, but cannot replace UFP monitoring.

Power law relation between particle concentrations and their sizes in the blood plasma

International Nuclear Information System (INIS)

Kirichenko, M N; Chaikov, L L; Zaritskii, A R

2016-01-01

This work is devoted to the investigation of sizes and concentrations of particles in blood plasma by dynamic light scattering (DLS). Blood plasma contains many different proteins and their aggregates, microparticles and vesicles. Their sizes, concentrations and shapes can give information about donor's health. Our DLS study of blood plasma reveals unexpected dependence: with increasing of the particle sizes r (from 1 nm up to 1 μm), their concentrations decrease as r -4 (almost by 12 orders). We found also that such dependence was repeated for model solution of fibrinogen and thrombin with power coefficient is -3,6. We believe that this relation is a fundamental law of nature that shows interaction of proteins (and other substances) in biological liquids. (paper)

Improved estimates of filtered total mercury loadings and total mercury concentrations of solids from potential sources to Sinclair Inlet, Kitsap County, Washington

Science.gov (United States)

Paulson, Anthony J.; Conn, Kathleen E.; DeWild, John F.

2013-01-01

Previous investigations examined sources and sinks of mercury to Sinclair Inlet based on historic and new data. This included an evaluation of mercury concentrations from various sources and mercury loadings from industrial discharges and groundwater flowing from the Bremerton naval complex to Sinclair Inlet. This report provides new data from four potential sources of mercury to Sinclair Inlet: (1) filtered and particulate total mercury concentrations of creek water during the wet season, (2) filtered and particulate total mercury releases from the Navy steam plant following changes in the water softening process and discharge operations, (3) release of mercury from soils to groundwater in two landfill areas at the Bremerton naval complex, and (4) total mercury concentrations of solids in dry dock sumps that were not affected by bias from sequential sampling. The previous estimate of the loading of filtered total mercury from Sinclair Inlet creeks was based solely on dry season samples. Concentrations of filtered total mercury in creek samples collected during wet weather were significantly higher than dry weather concentrations, which increased the estimated loading of filtered total mercury from creek basins from 27.1 to 78.1 grams per year. Changes in the concentrations and loading of filtered and particulate total mercury in the effluent of the steam plant were investigated after the water softening process was changed from ion-exchange to reverse osmosis and the discharge of stack blow-down wash began to be diverted to the municipal water-treatment plant. These changes reduced the concentrations of filtered and particulate total mercury from the steam plant of the Bremerton naval complex, which resulted in reduced loadings of filtered total mercury from 5.9 to 0.15 grams per year. Previous investigations identified three fill areas on the Bremerton naval complex, of which the western fill area is thought to be the largest source of mercury on the base

Height profile of particle concentration in an aeolian saltating cloud: A wind tunnel investigation by PIV MSD

Science.gov (United States)

Dong, Zhibao; Wang, Hongtao; Zhang, Xiaohang; Ayrault, Michael

2003-10-01

Attempt is made to define the particle concentration in an aeolian saltating cloud and its variation with height using artificial spherical quartz sand in a wind tunnel. The height profiles of the relative particle concentration in aeolian saltating cloud at three wind velocities were detected by the state of the art PIV (Particle Image Velocimetry) MSD (Mie Scattering Diffusion) technique, and converted to actual concentration based on sand transport rate and the variation with height of velocity of the saltating cloud. The particle concentration was found to decay exponentially with height and to increase with wind velocity. It decayed more rapidly when the wind velocity decreased. The volume/volume concentration in the near-surface layer was at the order of 10-4. The results obtained by PIV MSD technique were in good agreement with those derived from the sand flux and velocity profiles, the former being about 15% greater than the later.

Influence of fixed and moving bed biofilters on micro particle dynamics in a recirculating aquaculture system

DEFF Research Database (Denmark)

Fernandes, Paulo; Pedersen, Lars-Flemming; Pedersen, Per Bovbjerg

2017-01-01

(Oncorhynchus mykiss), and operatedunder constant feed loading conditions (1 kg feed/m3of make-up water) for more than three months.Production or removal of micro particles according to biofilter mode of operation (FBB vs. MBB) wasassessed by operating all biofilters simultaneously as well as separately...... particle concentration also represented a 10% reduction in total particle surface area and particlevolume. In MBB, a 10% increase in particle concentration also represented a 10% increase in total particlesurface area, but had no effect on total particle volume. A volumetric reduction of particles >100 m...... due to disintegration of particles inMBB. In the RAS, ammonia and nitrite were observed at concentrations below 0.20 mg N/L throughoutthe majority of the experiment. However, during the phase where only MBB were in operation, TAN(Total Ammonia Nitrogen) and nitrite levels increased significantly...

Mass and elemental concentrations of air bone particles at Kuala Lumpur site in 2000 to 2006

International Nuclear Information System (INIS)

Abdul Khalik Wood; Mohd Suhaimi Hamzah; Shamsiah Abdul Rahman

2008-01-01

Atmospheric Pollution due to air bone particle is a major concern to many cities in the Southeast Asian region, including Kuala Lumpur. Within the last six years air particulate samples have been collected from a site in Kuala Lumpur and measured for their PM10, PM2.5 and elemental concentrations. The results showed that the daily PM10 (<10μ diameter) concentrations were generally acceptable but the values occasionally very high, especially during the haze episodes. The PM10 annual average values were just below the national set standard and these values were mostly contributed by the fine particles (<2μ diameter) concentration. The annual average for PM2.5 (fine particle) concentrations over the past few years were considerably high where elemental carbon, sulfur and potassium were the main components. (Author)

Effect of gamma radiation on total antioxidant capacity, total lipid concentration and shelf life of finger millet flour

International Nuclear Information System (INIS)

Lathika; Manupriya, B.R.; Shenoy, K.B.; Patil, S.L.; Somashekarappa, H.M.

2016-01-01

The present study is an attempt to study the impact of gamma radiation on the shelf life, total antioxidant capacity and total lipid concentration of finger millet (Eleusine coracana L.) flour. Finger millet flour was procured from market. Flour samples of 50 g were taken in triplicates in a polyethylene pouch, air sealed and subjected to gamma irradiation doses ranging from 0.25 to 10 kGy and stored in polyethylene bags and plastic containers for a period of 1 year. Within 24 hours of irradiation, the samples were tested for moisture (2 ± 0.2%), total antioxidant capacity (0.12 ± 0.010 mg) and lipid concentration (15 ± 0.4 mg)

Preferential Concentration Of Solid Particles In Turbulent Horizontal Circular Pipe Flow

Science.gov (United States)

Kim, Jaehee; Yang, Kyung-Soo

2017-11-01

In particle-laden turbulent pipe flow, turbophoresis can lead to a preferential concentration of particles near the wall. To investigate this phenomenon, one-way coupled Direct Numerical Simulation (DNS) has been performed. Fully-developed turbulent pipe flow of the carrier fluid (air) is at Reτ = 200 based on the pipe radius and the mean friction velocity, whereas the Stokes numbers of the particles (solid) are St+ = 0.1 , 1 , 10 based on the mean friction velocity and the kinematic viscosity of the fluid. The computational domain for particle simulation is extended along the axial direction by duplicating the domain of the fluid simulation. By doing so, particle statistics in the spatially developing region as well as in the fully-developed region can be obtained. Accumulation of particles has been noticed at St+ = 1 and 10 mostly in the viscous sublayer, more intensive in the latter case. Compared with other authors' previous results, our results suggest that drag force on the particles should be computed by using an empirical correlation and a higher-order interpolation scheme even in a low-Re regime in order to improve the accuracy of particle simulation. This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP) (No. 2015R1A2A2A01002981).

Ultrafine particles in inhabited areas in the Arctic - From very low to high concentrations

DEFF Research Database (Denmark)

Pétursdóttir, Una; Kirkelund, Gunvor Marie; Press-Kristensen, Kåre

2017-01-01

The Arctic is considered a pristine environment, where pollution mainly originates from global sources. The present study examines particle number concentrations (PNCs) and the main sources of airborne ultrafine particles (UFPs, d < 100 nm) in the town Sisimiut and two nearby settlements, Sarfann......The Arctic is considered a pristine environment, where pollution mainly originates from global sources. The present study examines particle number concentrations (PNCs) and the main sources of airborne ultrafine particles (UFPs, d ..., Sarfannguit and Itilleq, in West Greenland. Measurements were carried out during three weeks in April and May 2016. Air temperatures during the measurements ranged from −4.4 to +8.7 °C. A portable condensation particle counter (P-Trak) was used for the measurements. Results showed that the lowest...... in Sisimiut, while subsequent measurements at the same location showed much lower PNCs. The presence of heavy machinery elevated PNCs highly during two measurement events, giving PNCs up to 270,993 cm−3 but dropping to 1180 cm−3 10 min later, after the vehicle had passed by. A measurement event in Sisimiut...

First passage times in homogeneous nucleation: Dependence on the total number of particles

International Nuclear Information System (INIS)

Yvinec, Romain; Bernard, Samuel; Pujo-Menjouet, Laurent; Hingant, Erwan

2016-01-01

Motivated by nucleation and molecular aggregation in physical, chemical, and biological settings, we present an extension to a thorough analysis of the stochastic self-assembly of a fixed number of identical particles in a finite volume. We study the statistics of times required for maximal clusters to be completed, starting from a pure-monomeric particle configuration. For finite volumes, we extend previous analytical approaches to the case of arbitrary size-dependent aggregation and fragmentation kinetic rates. For larger volumes, we develop a scaling framework to study the first assembly time behavior as a function of the total quantity of particles. We find that the mean time to first completion of a maximum-sized cluster may have a surprisingly weak dependence on the total number of particles. We highlight how higher statistics (variance, distribution) of the first passage time may nevertheless help to infer key parameters, such as the size of the maximum cluster. Finally, we present a framework to quantify formation of macroscopic sized clusters, which are (asymptotically) very unlikely and occur as a large deviation phenomenon from the mean-field limit. We argue that this framework is suitable to describe phase transition phenomena, as inherent infrequent stochastic processes, in contrast to classical nucleation theory

Effect of indirect non-thermal plasma on particle size distribution and composition of diesel engine particles

Science.gov (United States)

Linbo, GU; Yixi, CAI; Yunxi, SHI; Jing, WANG; Xiaoyu, PU; Jing, TIAN; Runlin, FAN

2017-11-01

To explore the effect of the gas source flow rate on the actual diesel exhaust particulate matter (PM), a test bench for diesel engine exhaust purification was constructed, using indirect non-thermal plasma technology. The effects of different gas source flow rates on the quantity concentration, composition, and apparent activation energy of PM were investigated, using an engine exhaust particle sizer and a thermo-gravimetric analyzer. The results show that when the gas source flow rate was large, not only the maximum peak quantity concentrations of particles had a large drop, but also the peak quantity concentrations shifted to smaller particle sizes from 100 nm to 80 nm. When the gas source flow rate was 10 L min-1, the total quantity concentration greatly decreased where the removal rate of particles was 79.2%, and the variation of the different mode particle proportion was obvious. Non-thermal plasma (NTP) improved the oxidation ability of volatile matter as well as that of solid carbon. However, the NTP gas source rate had little effects on oxidation activity of volatile matter, while it strongly influenced the oxidation activity of solid carbon. Considering the quantity concentration and oxidation activity of particles, a gas source flow rate of 10 L min-1 was more appropriate for the purification of particles.

Characterization of particle number concentrations and PM2.5 in a school: influence of outdoor air pollution on indoor air.

Science.gov (United States)

Guo, Hai; Morawska, Lidia; He, Congrong; Zhang, Yanli L; Ayoko, Godwin; Cao, Min

2010-07-01

The impact of air pollution on school children's health is currently one of the key foci of international and national agencies. Of particular concern are ultrafine particles which are emitted in large quantities, contain large concentrations of toxins and are deposited deeply in the respiratory tract. In this study, an intensive sampling campaign of indoor and outdoor airborne particulate matter was carried out in a primary school in February 2006 to investigate indoor and outdoor particle number (PN) and mass concentrations (PM(2.5)), and particle size distribution, and to evaluate the influence of outdoor air pollution on the indoor air. For outdoor PN and PM(2.5), early morning and late afternoon peaks were observed on weekdays, which are consistent with traffic rush hours, indicating the predominant effect of vehicular emissions. However, the temporal variations of outdoor PM(2.5) and PN concentrations occasionally showed extremely high peaks, mainly due to human activities such as cigarette smoking and the operation of mower near the sampling site. The indoor PM(2.5) level was mainly affected by the outdoor PM(2.5) (r = 0.68, p changes to the modal structure of particle number and size distribution, even though the I/O ratio was different for different size classes. The I/O curves had a maximum value for particles with diameters of 100-400 nm under both occupied and unoccupied scenarios, whereas no significant difference in I/O ratio for PM(2.5) was observed between occupied and unoccupied conditions. Inspection of the size-resolved I/O ratios in the preschool centre and the classroom suggested that the I/O ratio in the preschool centre was the highest for accumulation mode particles at 600 nm after school hours, whereas the average I/O ratios of both nucleation mode and accumulation mode particles in the classroom were much lower than those of Aitken mode particles. The findings obtained in this study are useful for epidemiological studies to estimate the

Concentration and flux of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids for monitored tributaries of Lake Champlain, 1990-2012

Science.gov (United States)

Medalie, Laura

2014-01-01

Annual and daily concentrations and fluxes of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids were estimated for 18 monitored tributaries to Lake Champlain by using the Weighted Regressions on Time, Discharge, and Seasons regression model. Estimates were made for 21 or 23 years, depending on data availability, for the purpose of providing timely and accessible summary reports as stipulated in the 2010 update to the Lake Champlain “Opportunities for Action” management plan. Estimates of concentration and flux were provided for each tributary based on (1) observed daily discharges and (2) a flow-normalizing procedure, which removed the random fluctuations of climate-related variability. The flux bias statistic, an indicator of the ability of the Weighted Regressions on Time, Discharge, and Season regression models to provide accurate representations of flux, showed acceptable bias (less than ±10 percent) for 68 out of 72 models for total and dissolved phosphorus, total nitrogen, and chloride. Six out of 18 models for total suspended solids had moderate bias (between 10 and 30 percent), an expected result given the frequently nonlinear relation between total suspended solids and discharge. One model for total suspended solids with a very high bias was influenced by a single extreme value; however, removal of that value, although reducing the bias substantially, had little effect on annual fluxes.

Measurement of radon progeny concentrations in air by alpha-particle spectrometey

International Nuclear Information System (INIS)

Kerr, G.D.

1975-07-01

A technique is presented for measuring air concentrations of the short-lived progeny of radon-222 by the use of alpha spectrometry. In this technique, the concentration of RaA, RaB, and RaC are calculated from one integral count of the RaA and two integral counts of the RaC' alpha-particle activity collected on a filter with an air sampling device. The influence of air sampling and counting intervals of time on the accuracy of the calculated concentrations is discussed in the report. A computer program is presented for use with this technique. It is written in the BASIC language. The program will calculate the air concentrations of RaA, RaB, and RaC, and will estimate the accuracy in these calculated concentrations. (U.S.)

How do changes in bulk soil organic carbon content affect carbon concentrations in individual soil particle fractions?

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Yang, X. M.; Drury, C. F.; Reynolds, W. D.; Yang, J. Y.

2016-06-01

We test the common assumption that organic carbon (OC) storage occurs on sand-sized soil particles only after the OC storage capacity on silt- and clay-sized particles is saturated. Soil samples from a Brookston clay loam in Southwestern Ontario were analysed for the OC concentrations in bulk soil, and on the clay (<2 μm), silt (2-53 μm) and sand (53-2000 μm) particle size fractions. The OC concentrations in bulk soil ranged from 4.7 to 70.8 g C kg-1 soil. The OC concentrations on all three particle size fractions were significantly related to the OC concentration of bulk soil. However, OC concentration increased slowly toward an apparent maximum on silt and clay, but this maximum was far greater than the maximum predicted by established C sequestration models. In addition, significant increases in OC associated with sand occurred when the bulk soil OC concentration exceeded 30 g C kg-1, but this increase occurred when the OC concentration on silt + clay was still far below the predicted storage capacity for silt and clay fractions. Since the OC concentrations in all fractions of Brookston clay loam soil continued to increase with increasing C (bulk soil OC content) input, we concluded that the concept of OC storage capacity requires further investigation.

Relationship between red wine grades and phenolics. 1. Tannin and total phenolics concentrations.

Science.gov (United States)

Mercurio, Meagan D; Dambergs, Robert G; Cozzolino, Daniel; Herderich, Markus J; Smith, Paul A

2010-12-08

Measuring chemical composition is a common approach to support decisions about allocating foods and beverages to grades related to market value. Red wine is a particularly complex beverage, and multiple compositional attributes are needed to account for its sensory properties, including measurement of key phenolic components such as anthocyanins, total phenolics, and tannin, which are related to color and astringency. Color has been shown to relate positively to red wine grade; however, little research has been presented that explores the relationship between astringency-related components such as total phenolic or tannin concentration and wine grade. The aim of this research has been to investigate the relationship between the wine grade allocations of commercial wineries and total phenolic and tannin concentrations, respectively, in Australian Shiraz and Cabernet Sauvignon wines. Total phenolic and tannin concentrations were determined using the methyl cellulose precipitable (MCP) tannin assay and then compared to wine grade allocations made by winemaker panels during the companies' postvintage allocation process. Data were collected from wines produced by one Australian wine company over the 2005, 2006, and 2007 vintages and by a further two companies in 2007 (total wines = 1643). Statistical analysis revealed a positive trend toward higher wine grade allocation and wines that had higher concentrations of both total phenolics and tannin, respectively. This research demonstrates that for these companies, in general, Cabernet Sauvignon and Shiraz wines allocated to higher market value grades have higher total phenolics and higher tannin concentrations and suggests that these compositional parameters should be considered in the development of future multiparameter decision support systems for relevant commercial red wine grading processes. In addition, both tannin and total phenolics would ideally be included because although, in general, a positive relationship

Control of respirable particles and radon progeny with portable air cleaners

International Nuclear Information System (INIS)

Offermann, F.J.; Sextro, R.G.; Fisk, W.J.; Nazaroff, W.W.; Nero, A.V.; Revzan, K.L.; Yater, J.

1984-02-01

Eleven portable air cleaning devices have been evaluated for control of indoor concentrations of respirable particles and radon progeny. Following injection of cigarette smoke and radon in a room-size chamber, decay rates for particles and radon progeny concentrations were measured with and without air cleaner operation. Particle concentrations were obtained for total number concentration and for number concentration by particle size. In tests with no air cleaner the natural decay rate for cigarette smoke was observed to be 0.2 hr -1 . Air cleaning rates for particles were found to be negligible for several small panel-filters, a residential ion-generator, and a pair of mixing fans. The electrostatic precipitators and extended surface filters tested had significant particle removal rates, and a HEPA-type filter was the most efficient air cleaner. The evaluation of radon progeny control produced similar results; the air cleaners which were effective in removing particles were also effective in removing radon progeny. At low particle concentrations plateout of the unattached radon progeny is an important removal mechanism. Based on data from these tests, the plateout rate for unattached progeny was found to be 15 hr -1 . The unattached fraction and the overall removal rate due to deposition of attached and unattached nuclides have been estimated for each radon decay product as a function of particle concentration. While air cleaning can be effective in reducing total radon progeny, concentrations of unattached radon progeny can increase with increasing air cleaning. 39 references, 26 figures, 9 tables

Genotoxic effects of daily personal exposure to particle mass and number concentrations on buccal cells

Science.gov (United States)

de Almeida, Daniela S.; da Costa, Silvano César; Ribeiro, Marcos; Moreira, Camila A. B.; Beal, Alexandra; Squizzato, Rafaela; Rudke, Anderson Paulo; Rafee, Sameh Adib Abou; Martins, Jorge A.; Palioto, Graciana Freitas; Kumar, Prashant; Martins, Leila D.

2018-03-01

The aim of this study is to assess personal exposure to Particle Number Concentrations (PNC) in four size ranges between 0.3 and 10 μm, and particulate matter (PM1; PM2.5; PM4; PM10) in order to evaluate possible genotoxic effects through a comet assay in buccal cells. A convenience cohort of 30 individuals from a Brazilian medium-sized city was selected. These individuals aged between 20 and 61 and worked in typical job categories (i.e., administrative, commerce, education, general services and transport). They were recruited to perform personal exposure measurements during their typical daily routine activities, totaling 240 h of sampling. The 8-h average mass concentrations in air for volunteers ranged from 2.4 to 31.8 μg m-3 for PM1, 4.2-45.1 μg m-3 for PM2.5, 7.9-66.1 μg m-3 for PM4 and from 23.1 to 131.7 μg m-3 for PM10. The highest PNC variation was found for 0.3-0.5 range, between 14 and 181 particles cm-3, 1 to 14 particles cm-3 for the 0.5-1.0 range, 0.2 to 2 particles cm-3 for the 1.0-2.5 range, and 0.06 to 0.7 particles cm-3 for the 2.5-10 range. Volunteers in the 'education' category experienced the lowest inhaled dose of PM2.5, as opposed to those involved in 'commercial' activities with the highest doses for PM10 (1.63 μg kg-1 h-1) and PM2.5 (0.61 μg kg-1 h-1). The predominant cause for these high doses was associated with the proximity of the workplace to the street and vehicle traffic. The comet assay performed in buccal cells indicated that the volunteers in 'commerce' category experienced the highest damage to their DeoxyriboNucleic Acid (DNA) compared with the control category (i.e. 'education'). These results indicate the variability in personal exposure of the volunteers in different groups, and the potential damage to DNA was much higher for those spending time in close proximity to the vehicle sources (e.g. commercial services) leading to exposure to a higher fraction of fine particles. This study builds understanding on the exposure

Evaluation of indoor aerosol control devices and their effects on radon progeny concentrations. Revision

International Nuclear Information System (INIS)

Sextro, R.G.; Offermann, F.J.; Nazaroff, W.W.; Nero, A.V.; Revzan, K.L.; Yater, J.

1984-11-01

Eleven portable air cleaning devices have been evaluated for control of indoor concentrations of respirable particles, and their concomitant effects on radon progeny concentrations have been investigated. The experiments were conducted in a room-size chamber using cigarette smoke and radon injection from an external source. Of the devices examined the electrostatic precipitators and extended surface filters had significant particle removal rates, while the particle removal rates for several small panel-filters, an ion-generator, and a pair of mixing fans were found to be essentially negligible. The evaluation of radon progeny control produced similar results; the air cleaners which were effective in removing particles were also effective in reducing radon progeny concentrations. At the low particle concentrations, deposition of the unattached radon progeny on room surfaces was found to be a significant removal mechanism. Deposition rates of attached and unattached progeny have been estimated from these data, and were used to calculate the equilibrium factors for total and unattached progeny concentrations as a function of particle concentration. While particle removal reduces total airborne radon progeny concentrations, the relative alpha decay dose to the lungs appears to change very little as the particle concentration decreases due to the greater radiological importance of unattached progeny

The effect of particle size and concentration on the flow properties of a homogeneous slurry

International Nuclear Information System (INIS)

Abbas, M.A.; Crowe, C.T.

1986-01-01

This paper presents the results of the effects of particle size and concentration on the velocity distribution in the fully developed flow of a homogeneous slurry. The slurry consisted of chloroform and silica gel with matched index of refraction to enable Laser-Doppler anemometry (LDA) measurements through the mixture. Slurries with two particle sizes and solids concentration up to 30% by volume were studied. Measurements were made over a Reynolds number range of 1,200 to 30,000

Dielectric compound parabolic concentrating solar collector with frustrated total internal reflection absorber

Science.gov (United States)

Hull, J. R.

Since its introduction, the concept of nonimaging solar concentrators, as exemplified by the compound parabolic concentrator (CPC) design, has greatly enhanced the ability to collect solar energy efficiently in thermal and photovoltaic devices. When used as a primary concentrator, a CPC can provide significant concentration without the complication of a tracking mechanism and its associated maintenance problems. When used as a secondary, a CPC provides higher total concentration, or for a fixed concentration, tolerates greater tracking error in the primary.

Contributions of Organic Sources to Atmospheric Aerosol Particle Concentrations and Growth

Science.gov (United States)

Russell, L. M.

2017-12-01

Organic molecules are important contributors to aerosol particle mass and number concentrations through primary emissions as well as secondary growth in the atmosphere. New techniques for measuring organic aerosol components in atmospheric particles have improved measurements of this contribution in the last 20 years, including Scanning Transmission X-ray Microscopy Near Edge X-ray Absorption Fine Structure (STXM-NEXAFS), Fourier Transform Infrared spectroscopy (FTIR), and High-Resolution Aerosol Mass Spectrometry (AMS). STXM-NEXAFS individual aerosol particle composition illustrated the variety of morphology of organic components in marine aerosols, the inherent relationships between organic composition and shape, and the links between atmospheric aerosol composition and particles produced in smog chambers. This type of single particle microscopy has also added to size distribution measurements by providing evidence of how surface-controlled and bulk-controlled processes contribute to the growth of particles in the atmosphere. FTIR analysis of organic functional groups are sufficient to distinguish combustion, marine, and terrestrial organic particle sources and to show that each of those types of sources has a surprisingly similar organic functional group composition over four different oceans and four different continents. Augmenting the limited sampling of these off-line techniques with side-by-side inter-comparisons to online AMS provides complementary composition information and consistent quantitative attribution to sources (despite some clear method differences). Single-particle AMS techniques using light scattering and event trigger modes have now also characterized the types of particles found in urban, marine, and ship emission aerosols. Most recently, by combining with off-line techniques, single particle composition measurements have separated and quantified the contributions of organic, sulfate and salt components from ocean biogenic and sea spray

[Relationship between atmospheric particles and rain water chemistry character].

Science.gov (United States)

Huo, Ming-Qun; Sun, Qian; Xie, Peng; Bai, Yu-Hua; Liu, Zhao-Rong; Li, Ji-Long; Lu, Si-Hua

2009-11-01

Rain and atmospheric particle samples were collected in the rural area of Taian and Shenzhen in 2007, respectively. Rain sampling was carried out during the precipitation process and several samples were got from the beginning of one precipitation to the end. The chemical character changes during precipitation and the changes of concentration of particles before and after rain were studied in this research to understand the contribution of particles on the rain chemical character and the rain-out effect for particles. The volume-weighted mean pH of rainwater in Taian was 5.97 and the total concentration of ions was 1 187.96 microeq x L(-1). The mass concentration of PM10 in Taian was 131.76 microg/m3 and that of PM2.5 was 103.84 microg/m3. The volume-weighted mean pH of rainwater in Shenzhen was 4.72 and the total concentration of ions was 175.89 microeq x L(-1). The mass concentration of PM10 in Shenzhen was 56.66 microg/m3 and that of PM2.5 was 41.52 microg/m3. During precipitation process pH and ion concentration of rain decrease and it is shown the neutralizing effect happens. The difference between rainwater of Taian and Shenzhen is due to cloud water acidity, atmospheric particles character and atmospheric acid-basic gases concentration. The clean-up effect of Na+ and Ca2+ by rain is high and which of NH4+ and NO3- is low. The clean-up effect for mass concentration, ions concentration and element concentration of particles by rain are significant.

N-3 polyunsaturated fatty acids improve lipoprotein particle size and concentration in Japanese patients with type 2 diabetes and hypertriglyceridemia: a pilot study.

Science.gov (United States)

Ide, Kana; Koshizaka, Masaya; Tokuyama, Hirotake; Tokuyama, Takahiko; Ishikawa, Takahiro; Maezawa, Yoshiro; Takemoto, Minoru; Yokote, Koutaro

2018-03-15

Patients with type 2 diabetes are at high risk for cardiovascular disease. Although hydroxymethylglutaryl-CoA reductase inhibitors (statins) can reduce cardiovascular events, residual risk remains even after target low-density lipoprotein cholesterol (LDL-C) levels have been achieved. Lipoprotein particle size and fraction changes are thought to contribute to such risks. The purpose of this study was to evaluate the effects of n-3 polyunsaturated fatty acids (n-3 PUFAs), predominantly eicosapentaenoic acid and docosahexaenoic acid, on lipoprotein particle size, concentration, and glycemic control in Japanese patients with type 2 diabetes and hypertriglyceridemia. This was a multicenter, prospective, open-label, single arm study. We enrolled 14 patients with type 2 diabetes and hypertriglyceridemia treated with statins and dipeptidyl peptidase-4 inhibitors with glycated hemoglobin (HbA1c) n-3 PUFAs for 12 weeks. Lipoprotein particle sizes, concentrations, lipoprotein insulin resistance (LPIR) scores, lipid profiles, HbA1c, and fasting plasma glucose (FPG) were measured before and after treatment. Lipoprotein profiles were measured by nuclear magnetic resonance spectroscopy. Data were analyzed using Wilcoxon signed-rank tests. Concentrations of total cholesterol (P n-3 PUFA administration. N-3 PUFAs decreased the size of very low-density lipoprotein (VLDL; P N-3 PUFAs partly improved atherogenic lipoprotein particle size and concentration, and produced less atherogenic lipoprotein subclass ratios in patients that achieved target LDL-C levels and glycemic control. These results suggest that n-3 PUFAs may reduce residual cardiovascular risk factors in statin-treated patients with type 2 diabetes and hypertriglyceridemia. The study was registered at UMIN-ID: UMIN000013776 .

Seasonal variation of atmospheric particle number concentrations, new particle formation and atmospheric oxidation capacity at the high Arctic site Villum Research Station, Station Nord

Directory of Open Access Journals (Sweden)

Q. T. Nguyen

2016-09-01

Full Text Available This work presents an analysis of the physical properties of sub-micrometer aerosol particles measured at the high Arctic site Villum Research Station, Station Nord (VRS, northeast Greenland, between July 2010 and February 2013. The study focuses on particle number concentrations, particle number size distributions and the occurrence of new particle formation (NPF events and their seasonality in the high Arctic, where observations and characterization of such aerosol particle properties and corresponding events are rare and understanding of related processes is lacking.A clear accumulation mode was observed during the darker months from October until mid-May, which became considerably more pronounced during the prominent Arctic haze months from March to mid-May. In contrast, nucleation- and Aitken-mode particles were predominantly observed during the summer months. Analysis of wind direction and wind speed indicated possible contributions of marine sources from the easterly side of the station to the observed summertime particle number concentrations, while southwesterly to westerly winds dominated during the darker months. NPF events lasting from hours to days were mostly observed from June until August, with fewer events observed during the months with less sunlight, i.e., March, April, September and October. The results tend to indicate that ozone (O3 might be weakly anti-correlated with particle number concentrations of the nucleation-mode range (10–30 nm in almost half of the NPF events, while no positive correlation was observed. Calculations of air mass back trajectories using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT model for the NPF event days suggested that the onset or interruption of events could possibly be explained by changes in air mass origin. A map of event occurrence probability was computed, indicating that southerly air masses from over the Greenland Sea were more likely linked to those

Highly Localized Acoustic Streaming and Size-Selective Submicrometer Particle Concentration Using High Frequency Microscale Focused Acoustic Fields.

Science.gov (United States)

Collins, David J; Ma, Zhichao; Ai, Ye

2016-05-17

Concentration and separation of particles and biological specimens are fundamental functions of micro/nanofluidic systems. Acoustic streaming is an effective and biocompatible way to create rapid microscale fluid motion and induce particle capture, though the >100 MHz frequencies required to directly generate acoustic body forces on the microscale have traditionally been difficult to generate and localize in a way that is amenable to efficient generation of streaming. Moreover, acoustic, hydrodynamic, and electrical forces as typically applied have difficulty manipulating specimens in the submicrometer regime. In this work, we introduce highly focused traveling surface acoustic waves (SAW) at high frequencies between 193 and 636 MHz for efficient and highly localized production of acoustic streaming vortices on microfluidic length scales. Concentration occurs via a novel mechanism, whereby the combined acoustic radiation and streaming field results in size-selective aggregation in fluid streamlines in the vicinity of a high-amplitude acoustic beam, as opposed to previous acoustic radiation induced particle concentration where objects typically migrate toward minimum pressure locations. Though the acoustic streaming is induced by a traveling wave, we are able to manipulate particles an order of magnitude smaller than possible using the traveling wave force alone. We experimentally and theoretically examine the range of particle sizes that can be captured in fluid streamlines using this technique, with rapid particle concentration demonstrated down to 300 nm diameters. We also demonstrate that locations of trapping and concentration are size-dependent, which is attributed to the combined effects of the acoustic streaming and acoustic forces.

Effect of gamma irradiation on total carbohydrate concentration of finger millet flour

International Nuclear Information System (INIS)

Lathika; Patil, Shrikant L.; Bhasker Shenoy, K.; Somashekarappa, H.M.

2015-01-01

Ragi or finger millet (Eleusine coracana L.) is one of the common millets in several regions of India. The effect of gamma irradiation, on ragi flour was investigated in the study. Ragi flour is procured from market. Flour samples of 50 gms were taken in triplicates in a polyethylene pouch, air sealed and subjected to gamma irradiation doses ranging from 0.25 to 10 kGy and stored in polyethylene bags and plastic containers for a period of 30 and 90 days. Within 24 hours of irradiation, the samples were tested for total carbohydrate concentration by phenol-sulphuric acid method. The same was repeated after 30 and 90 days of storage. The comparative study showed that, at 0 day, total carbohydrate concentration has decreased slightly when compared to the non-irradiated sample (0.024 mg/ml). The lowest concentration of carbohydrate is seen at 0.025 kGy (0.019mg/ml). The samples stored in polyethylene bag, after 30 days showed both increase (0.056 mg/ml at 0.025 kGy) and decrease (0.04 mg/ml at 10 kGy) in total carbohydrate concentration when compared to control (0.046 mg/ml). 90 days stored samples showed increase in carbohydrate concentration when compared to control (0.029 mg/ml). The highest carbohydrate concentration is seen in 1 kGy dose (0.037 mg/ml). The samples stored at container after 30 days showed both increase (0.045 mg/ml at 5 kGy) and decrease (0.034 mg/ml at 0.025 mg/ml) of carbohydrate concentration when compared to control (0.043 mg/ml). 90 days stored samples showed decrease in carbohydrate concentration when compared to control (0.034 mg/ml). The lowest concentration is seen at 5 kGy (0.022 mg/ml). (author)

Behaviour of solute and particle markers in the stomach of sheep given a concentrate diet

International Nuclear Information System (INIS)

Faichney, G.J.; Griffiths, D.A.

1978-01-01

Fistulated sheep given a concentrate diet were used to study the behaviour of solute ([ 51 Cr]EDTA) and particle ([ 103 Ru]phenanthroline) markers in the stomach under conditions of continuous feeding. An injection of a mixed dose of [ 51 Cr]EDTA and [ 103 Ru]phenanthroline was given into the rumen and the time course of marker concentrations in the rumen and the abomasum was recorded. The curves were analysed on the assumption that the stomach of the sheep could be represented as two mixing compartments (reticulo-rumen and abomasum) and a time delay (omasum). This model provided a very good description of the data. [ 103 Ru]-phenanthroline associated with small particles was retained in the rumen much longer than [ 51 Cr]EDTA. Although exchange of [ 103 Ru] phenanthroline occurred between large and small particle fractions, the results suggested that small particles may have been retained somewhat longer in the rumen than solutes. However, it was clear from the results that the mean retention times for particulate matter in the rumen could not be simply obtained using adsorbable markers. Cyclical fluctuations in the concentration of [ 51 Cr]EDTA in the rumen indicated that there were daily variations in net water flux in the rumen. The presence of protozoa was associated with much shorter retention times of both solutes and particles in the rumen. Protozoa were also associated with reduced rumen volumes. (author)

Determination of plutonium isotopic ratios and total concentration by gamma ray spectrometry

International Nuclear Information System (INIS)

Despres, Michele.

1980-11-01

A non-destructive method of analysis is being investigated for the control in situ of plutonium isotopic composition and total concentration in different matrix without preliminary calibration. The plutonium isotopic composition is determined by gamma-ray spectrometry using germanium detector systems. The same apparatus is used for direct measuring of the total plutonium concentration in solutions or solids by a differential attenuation technique based on two transmitted gamma rays with energies on both sides of the k shell absorption edge of plutonium [fr

Omega-3 PUFA concentration by a novel PVDF nano-composite membrane filled with nano-porous silica particles.

Science.gov (United States)

Ghasemian, Samaneh; Sahari, Mohammad Ali; Barzegar, Mohsen; Ahmadi Gavlighi, Hasan

2017-09-01

In this study, polyvinylidene fluoride (PVDF) and nano-porous silica particle were used to fabricate an asymmetric nano-composite membrane. Silica particles enhanced the thermal stability of PVDF/SiO 2 membranes; increasing the decomposition temperature from 371°C to 408°C. Cross sectional morphology showed that silica particles were dispersed in polymer matrix uniformly. However, particle agglomeration was found at higher loading of silica (i.e., 20 by weight%). The separation performance of nano-composite membranes was also evaluated using the omega-3 polyunsaturated fatty acids (PUFA) concentration at a temperature and pressure of 30°C and 4bar, respectively. Silica particle increased the omega-3PUFA concentration from 34.8 by weight% in neat PVDF to 53.9 by weight% in PVDF with 15 by weight% of silica. Moreover, PVDF/SiO 2 nano-composite membranes exhibited enhanced anti-fouling property compared to neat PVDF membrane. Fouling mechanism analysis revealed that complete pore blocking was the predominant mechanism occurring in oil filtration. The concentration of omega-3 polyunsaturated fatty acids (PUFA) is important in the oil industries. While the current methods demand high energy consumptions in concentrating the omega-3, membrane separation technology offers noticeable advantages in producing pure omega-3 PUFA. Moreover, concentrating omega-3 via membrane separation produces products in the triacylglycerol form which possess better oxidative stability. In this work, the detailed mechanisms of fouling which limits the performance of membrane separation were investigated. Incorporating silica particles to polymeric membrane resulted in the formation of mixed matrix membrane with improved anti-fouling behaviour compared to the neat polymeric membrane. Hence, the industrial potential of membrane processing to concentrate omega-3 fatty acids is enhanced. Copyright © 2017. Published by Elsevier Ltd.

Sources of ultrafine particles in the Eastern United States

Science.gov (United States)

Posner, Laura N.; Pandis, Spyros N.

2015-06-01

Source contributions to ultrafine particle number concentrations for a summertime period in the Eastern U.S. are investigated using the chemical transport model PMCAMx-UF. New source-resolved number emissions inventories are developed for biomass burning, dust, gasoline automobiles, industrial sources, non-road and on-road diesel. According to the inventory for this summertime period in the Eastern U.S., gasoline automobiles are responsible for 40% of the ultrafine particle number emissions, followed by industrial sources (33%), non-road diesel (16%), on-road diesel (10%), and 1% from biomass burning and dust. With these emissions as input, the chemical transport model PMCAMx-UF reproduces observed ultrafine particle number concentrations (N3-100) in Pittsburgh with an error of 12%. For this summertime period in the Eastern U.S., nucleation is predicted to be the source of more than 90% of the total particle number concentrations. The source contributions to primary particle number concentrations are on average similar to those of their source emissions contributions: gasoline is predicted to contribute 36% of the total particle number concentrations, followed by industrial sources (31%), non-road diesel (18%), on-road diesel (10%), biomass burning (1%), and long-range transport (4%). For this summertime period in Pittsburgh, number source apportionment predictions for particles larger than 3 nm in diameter (traffic 65%, other combustion sources 35%) are consistent with measurement-based source apportionment (traffic 60%, combustion sources 40%).

A concentration correction scheme for Lagrangian particle model and its application in street canyon air dispersion modelling

Energy Technology Data Exchange (ETDEWEB)

Jiyang Xia [Shanghai Jiao Tong University, Shanghai (China). Department of Engineering Mechanics; Leung, D.Y.C. [The University of Hong Kong (Hong Kong). Department of Mechanical Engineering

2001-07-01

Pollutant dispersion in street canyons with various configurations was simulated by discharging a large number of particles into the computation domain after developing a time-dependent wind field. Trajectory of the released particles was predicted using a Lagrangian particle model developed in an earlier study. A concentration correction scheme, based on the concept of 'visibility', was adopted for the Lagrangian particle model to correct the calculated pollutant concentration field in street canyons. The corrected concentrations compared favourably with those from wind tunnel experiments and a linear relationship between the computed concentrations and wind tunnel data were found. The developed model was then applied to four simulations to test for the suitability of the correction scheme and to study pollutant distribution in street canyons with different configurations. For those cases with obstacles presence in the computation domain, the correction scheme gives more reasonable results compared with the one without using it. Different flow regimes are observed in the street canyons, which depend on building configurations. A counter-clockwise rotating vortex may appear in a two-building case with wind flow from left to right, causing lower pollutant concentration at the leeward side of upstream building and higher concentration at the windward side of downstream building. On the other hand, a stable clockwise rotating vortex is formed in the street canyon with multiple identical buildings, resulting in poor natural ventilation in the street canyon. Moreover, particles emitted in the downstream canyon formed by buildings with large height-to-width ratios will be transported to upstream canyons. (author)

Effects of wind on background particle concentrations at truck freight terminals.

Science.gov (United States)

Garcia, Ronald; Hart, Jaime E; Davis, Mary E; Reaser, Paul; Natkin, Jonathan; Laden, Francine; Garshick, Eric; Smith, Thomas J

2007-01-01

Truck freight terminals are predominantly located near highways and industrial facilities. This proximity to pollution sources, coupled with meteorological conditions and wind patterns, may affect occupational exposures to particles at these work locations. To understand this process, data from an environmental sampling study of particles at U.S. trucking terminals, along with weather and geographic maps, were analyzed to determine the extent to which the transportation of particles from local pollutant sources elevated observed occupational exposures at these locations. To help identify potential upwind sources, wind direction weighted averages and speed measurements were used to construct wind roses that were superimposed on overhead photos of the terminal and examined for upwind source activity. Statistical tests were performed on these "source" and "nonsource" directions to determine whether there were significant differences in observed particle levels between the two groups. Our results provide evidence that nearby upwind pollution sources significantly elevated background concentrations at only a few of the locations sampled, whereas the majority provided little to no evidence of a significant upwind source effect.

Characterization study of cesium concentrated particles in the soils near the Fukushima Daiichi nuclear power plant

Science.gov (United States)

Satou, Yukihiko; Sueki, Keisuke; Sasa, Kimikazu; Adachi, Kouji; Igarashi, Yasuhito

2015-04-01

Radionuclides from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident contaminated a vast area. Two types of contamination, spread and spot types, were observed in soils with autoradiography using an imaging plate. Other samples such as dust filters, vegetation, X-ray films, and so on, also indicate the spot type contamination in the early stage of the FDNPP accident. The source of spot type contamination is well known as hot particles at the Chernobyl Nuclear Power Plant (ChNPP) accident in 1986. Hot particles were divided into two groups, fuel hot particles and fission product particles, and they were emitted directly from reactor core with phreatic explosion and fire. In contrast, the official reports of the FDNPP accident did not conforme core explosion. In addition, the emitted total amount of Uranium was very few (Yamamoto et al., 2014). Thus, the spot type contaminations were not identified as the same of hot particles yet. Therefore, the present study aimed to pick up and identify the spot contaminations in soils. Surface soil samples were collected at 20 km northwest from the FDNPP in June 2013. Soils were spread in plastic bags for autoradiography with imaging plate analysis. Then, the soil particles were collected on a sticky carbon tape and analyzed by SEM-EDS to detect radioactive particles. Finally, particles were confirmed to contain photo peaks in the γ-spectrum by a germanium semiconductor detector. Four radioactive particles were isolated from the soil samples in the present study. Detected γ-ray emission radionuclides were only Cs-134 and Cs-137. The X-ray spectra on the SEM-EDS of all particles showed a Cs peak as well as O, Fe, Zn, and Rb peaks, and these elements were distributed uniformly within the particles. In addition, uniform distribution of Si was also shown. Moreover, U was detected from one of the particles, but U concentration was very low and existed locally in the particle. These characters are very similar to previous

Prediction of indoor concentration of 0.5-4 µm particles of outdoor origin in an uninhabited apartment

DEFF Research Database (Denmark)

Schneider, T.; Jensen, K.A.; Clausen, P.A.

2004-01-01

Indoor and outdoor particle size distributions, indoor-outdoor pressure difference, indoor air-exchange rate, and meteorological conditions were measured at an uninhabited apartment located in a busy street in Copenhagen during 1-month long fall, winter and spring campaigns. Particle penetration...... was estimated from concentration rebound measurements following HEPA filtering of the indoor air by fitting a simple deterministic model. The model included measured air exchange rates and published surface deposition loss rates. This model was then used to predict indoor particle concentration. The model...

Removal of two polycyclic musks in sewage treatment plants: Freely dissolved and total concentrations

NARCIS (Netherlands)

Artola-Garicano, E.; Borkent, I.; Hermens, J.L.M.; Vaes, W.H.J.

2003-01-01

In the current study, the removal of slowly degradable hydrophobic chemicals in sewage treatment plants (STPs) has been evaluated with emphasis on the combination of free and total concentration data. Free and total concentrations of two polycyclic musks were determined in each compartment of four

Effect of traffic restriction on atmospheric particle concentrations and their size distributions in urban Lanzhou, Northwestern China.

Science.gov (United States)

Zhao, Suping; Yu, Ye; Liu, Na; He, Jianjun; Chen, Jinbei

2014-02-01

During the 2012 Lanzhou International Marathon, the local government made a significant effort to improve traffic conditions and air quality by implementing traffic restriction measures. To evaluate the direct effect of these measures on urban air quality, especially particle concentrations and their size distributions, atmospheric particle size distributions (0.5-20 microm) obtained using an aerodynamic particle sizer (model 3321, TSI, USA) in June 2012 were analyzed. It was found that the particle number, surface area and volume concentrations for size range 0.5-10 microm were (15.0 +/- 2.1) cm(-3), (11.8 +/- 2.6) microm2/cm3 and (1.9 +/- 0.6) microm2/cm3, respectively, on the traffic-restricted day (Sunday), which is 63.2%, 53.0% and 47.2% lower than those on a normal Sunday. For number and surface area concentrations, the most affected size range was 0.5-0.7 and 0.5-0.8 microm, respectively, while for volume concentration, the most affected size ranges were 0.5-0.8, 1.7-2.0 and 5.0-5.4 microm. Number and volume concentrations of particles in size range 0.5-1.0 microm correlated well with the number of non-CNG (Compressed Natural Gas) powered vehicles, while their correlation with the number of CNG-powered vehicles was very low, suggesting that reasonable urban traffic controls along with vehicle technology improvements could play an important role in improving urban air quality.

25-hydroxyvitamin D, autoantigenic and total antibody concentrations

DEFF Research Database (Denmark)

Thorsen, Steffen Ullitz; Pipper, Christian B; Johannesen, Jesper

2018-01-01

conducted within this field. OBJECTIVE: Our objective was to investigate if higher 25-hydroxyvitamin D (25(OH)D) concentrations were inversely associated with β-cell autoantigens glutamic acid decarboxylase (isoform 65) (GADA) and insulinoma associated antigen-2A (IA-2A). Further, we also wanted to examine......BACKGROUND: B cells have recently entered the stage as an important accessory player in type 1 diabetes (T1D) etiopathogenesis. Experimental studies suggest regulatory functions of vitamin D on B cells. However, only a few human studies, with considerable methodological limitations, have been...... the relationship between 25(OH)D and total antibody concentrations. METHODS: We randomly selected 500 patients with newly diagnosed T1D and 500 siblings for 25(OH)D, antibody and genetic analysis from the population-based Danish Registry of Childhood and Adolescent Diabetes. The relative change (RC) in the mean...

Effect of concentrate feeding strategy on the performance of dairy cows fed total mixed rations

Directory of Open Access Journals (Sweden)

H. KHALILI

2008-12-01

Full Text Available Little information is available concerning the effects of offering additional concentrates with total mixed ration (TMR on milk production. The aim of the present study was to compare TMR representing simplified feeding (TMR1 with TMR combined with a decreasing amount of additional concentrate (TMR2C. Finnish Ayrshire cows (39 were housed in a loose housing barn. TMR1 consisted of a mixed ration of grass silage (0.49 and concentrates (0.51. In TMR2C, the same grass silage and concentrate were mixed in a ratio of 55:45. In TMR2C, cows were offered additional concentrates from automatic feeders differing in composition from the concentrate in TMR1 [6.5 kg d-1 (first 100 days, Phase 1, 3.0 kg d-1 (subsequent 50 days, Phase 2 and no concentrate thereafter (Phase 3]. During the whole experiment (224 days, total consumption of concentrates per cow averaged 2426 kg dry matter (TMR1 and 2414 kg dry matter (TMR2C. There were no significant differences in mean total dry matter, metabolizable energy, crude protein or absorbed amino acid intakes. During Phase 2, total intake of all cows fed TMR2C was one kg lower (P = 0.10 than for cows fed TMR1. This was due to differences in total feed intake of multiparous cows. Average yields (kg d-1 of milk, energy corrected milk, protein, fat and lactose were not significantly different between diets. During Phase 2, primiparous cows tended to produce more energy corrected milk on TMR2C than on TMR1. The results showed that both TMR1 and TMR2C were equal feeding strategies for early lactating cows and cows did not benefit from greater concentrate consumption in early stage of lactation when total consumption of concentrates was similar.;

Ultrasonic device for real-time sewage velocity and suspended particles concentration measurements.

Science.gov (United States)

Abda, F; Azbaid, A; Ensminger, D; Fischer, S; François, P; Schmitt, P; Pallarès, A

2009-01-01

In the frame of a technological research and innovation network in water and environment technologies (RITEAU, Réseau de Recherche et d'Innovation Technologique Eau et Environnement), our research group, in collaboration with industrial partners and other research institutions, has been in charge of the development of a suitable flowmeter: an ultrasonic device measuring simultaneously the water flow and the concentration of size classes of suspended particles. Working on the pulsed ultrasound principle, our multi-frequency device (1 to 14 MHz) allows flow velocity and water height measurement and estimation of suspended solids concentration. Velocity measurements rely on the coherent Doppler principle. A self developed frequency estimator, so called Spectral Identification method, was used and compared to the classical Pulse-Pair method. Several measurements campaigns on one wastewater collector of the French city of Strasbourg gave very satisfactory results and showed smaller standard deviation values for the Doppler frequency extracted by the Spectral Identification method. A specific algorithm was also developed for the water height measurements. It relies on the water surface acoustic impedance rupture and its peak localisation and behaviour in the collected backscattering data. This algorithm was positively tested on long time measurements on the same wastewater collector. A large part of the article is devoted to the measurements of the suspended solids concentrations. Our data analysis consists in the adaptation of the well described acoustic behaviour of sand to the behaviour of wastewater particles. Both acoustic attenuation and acoustic backscattering data over multiple frequencies are analyzed for the extrapolation of size classes and respective concentrations. Under dry weather conditions, the massic backscattering coefficient and the overall size distribution showed similar evolution whatever the measurement site was and were suggesting a global

High concentrations of coarse particles emitted from a cattle feeding operation

Science.gov (United States)

Hiranuma, N.; Brooks, S. D.; Gramann, J.; Auvermann, B. W.

2011-08-01

Housing roughly 10 million head of cattle in the United States alone, open air cattle feedlots represent a significant but poorly constrained source of atmospheric particles. Here we present a comprehensive characterization of physical and chemical properties of particles emitted from a large representative cattle feedlot in the Southwest United States. In the summer of 2008, measurements and samplings were conducted at the upwind and downwind edges of the facility. A series of far-field measurements and samplings was also conducted 3.5 km north of the facility. Two instruments, a GRIMM Sequential Mobility Particle Sizer (SMPS) and a GRIMM Portable Aerosol Spectrometer (PAS), were used to measure particle size distributions over the range of 0.01 to 25 μm diameter. Raman microspectroscopy was used to determine the chemical composition of particles on a single particle basis. Volume size distributions of dust were dominated by coarse mode particles. Twenty-four hour averaged concentrations of PM10 (particulate matter with a diameter of 10 μm or less) were as high as 1200 μg m-3 during the campaign. The primary constituents of the particulate matter were carbonaceous materials, such as humic acid, water soluble organics, and less soluble fatty acids, including stearic acid and tristearin. A significant fraction of the organic particles was present in internal mixtures with salts. Basic characteristics such as size distribution and composition of agricultural aerosols were found to be different than the properties of those found in urban and semi-urban aerosols. Failing to account for such differences may lead to errors in estimates of aerosol effects on local air quality, visibility, and public health.

Total selenium in irrigation drain inflows to the Salton Sea, California, April 2009

Science.gov (United States)

May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

2009-01-01

This report presents the results for the final sampling period (April 2009) of a 4-year monitoring program to characterize selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium and total suspended solids were determined in water samples. Total selenium, percent total organic carbon, and particle size were determined in sediments. Mean total selenium concentrations in water ranged from 0.98 to 22.9 micrograms per liter. Total selenium concentrations in sediment ranged from 0.078 to 5.0 micrograms per gram dry weight.

Determinants of spikes in ultrafine particle concentration whilst commuting by bus

Science.gov (United States)

Lim, Shanon; Dirks, Kim N.; Salmond, Jennifer A.; Xie, Shanju

2015-07-01

This paper examines concentration of ultrafine particles (UFPs) based on data collected using high-resolution UFP monitors whilst travelling by bus during rush hour along three different urban routes in Auckland, New Zealand. The factors influencing in-bus UFP concentration were assessed using a combination of spatial, statistical and GIS analysis techniques to determine both spatial and temporal variability. Results from 68 bus trips showed that concentrations varied more within a route than between on a given day, despite differences in urban morphology, land use and traffic densities between routes. A number of trips were characterised by periods of very rapid increases in UFPs (concentration 'spikes'), followed by slow declines. Trips which recorded at least one spike (an increase of greater than 10,000 pt/cm3) resulted in significantly higher mean concentrations. Spikes in UFPs were significantly more likely to occur when travelling at low speeds and when passengers were alighting and boarding at bus stops close to traffic light intersections.

Aerosol surface area concentration: a governing factor in new particle formation in Beijing

Directory of Open Access Journals (Sweden)

R. Cai

2017-10-01

Full Text Available The predominating role of aerosol Fuchs surface area, AFuchs, in determining the occurrence of new particle formation (NPF events in Beijing was elucidated in this study. The analysis was based on a field campaign from 12 March to 6 April 2016 in Beijing, during which aerosol size distributions down to  ∼  1 nm and sulfuric acid concentrations were simultaneously monitored. The 26 days were classified into 11 typical NPF days, 2 undefined days, and 13 non-event days. A dimensionless factor, LΓ, characterized by the relative ratio of the coagulation scavenging rate over the condensational growth rate (Kuang et al., 2010, was applied in this work to reveal the governing factors for NPF events in Beijing. The three parameters determining LΓ are sulfuric acid concentration, the growth enhancement factor characterized by contribution of other gaseous precursors to particle growth, Γ, and AFuchs. Different from other atmospheric environments, such as in Boulder and Hyytiälä, the daily-maximum sulfuric acid concentration and Γ in Beijing varied in a narrow range with geometric standard deviations of 1.40 and 1.31, respectively. A positive correlation between the estimated new particle formation rate, J1.5, and sulfuric acid concentration was found with a mean fitted exponent of 2.4. However, the maximum sulfuric acid concentrations on NPF days were not significantly higher (even lower, sometimes than those on non-event days, indicating that the abundance of sulfuric acid in Beijing was high enough to initiate nucleation, but may not necessarily lead to NPF events. Instead, AFuchs in Beijing varied greatly among days with a geometric standard deviation of 2.56, whereas the variabilities of AFuchs in Tecamac, Atlanta, and Boulder were reported to be much smaller. In addition, there was a good correlation between AFuchs and LΓ in Beijing (R2 = 0.88. Therefore, it was AFuchs that fundamentally determined the occurrence of NPF events

Wear particles and osteolysis in patients with total wrist arthroplasty

DEFF Research Database (Denmark)

Boeckstyns, Michel E H; Toxværd, Anders; Bansal, Manjula

2014-01-01

PURPOSE: To determine whether the amount of polyethylene debris in the interphase tissue between prosthesis and bone in patients with total wrist arthroplasty correlated with the degree of periprosthetic osteolysis (PPO); and to investigate the occurrence of metal particles in the periprosthetic...... tissue, the level of chrome and cobalt ions in the blood, and the possible role of infectious or rheumatoid activity in the development of PPO. METHODS: Biopsies were taken from the implant-bone interphase in 13 consecutive patients with total wrist arthroplasty and with at least 3 years' follow......-up. Serial annual radiographs were performed prospectively for the evaluation of PPO. We collected blood samples for white blood cell count, C-reactive protein, and metallic ion level. RESULTS: A radiolucent zone of greater than 2 mm was observed juxta-articular to the radial component in 4 patients...

Determination of diffusible and total hydrogen concentration in coated and uncoated steel

Energy Technology Data Exchange (ETDEWEB)

Mabho, Nonhlangabezo

2010-09-23

The new trend in the steel industry demands thin, flexible, high strength steels with low internal embrittlement. It is a well known fact that the atomic hydrogen which is picked up during production, fabrication and service embrittles the steel. This has led to an extensive research towards the improvement of the quality of metallic materials by focusing on total and diffusible hydrogen concentrations which are responsible for hydrogen embrittlement. Since the internal embrittlement cannot be foreseen, the concentrations of diffusible hydrogen work as indicators while the total hydrogen characterizes the absorbed quantities and quality of that particular product. To meet these requirements, the analytical chemistry methods which include the already existing carrier gas melt (fusion) extraction methods that use infrared and thermal conductivity for total hydrogen detection were applied. The newly constructed carrier gas thermal desorption mass spectroscopy was applied to monitor the diffusible concentration at specific temperatures and desorption rates of hydrogen which will contribute towards the quality of materials during service. The TDMS method also involved the characterization of the energy quantity (activation energy) required by hydrogen to be removed from traps of which irreversible traps are preferred because they enhance the stability of the product by inhibiting the mobility of hydrogen which is detrimental to the metallic structures. The instrumentation for TDMS is quite simple, compact, costs less and applicable to routine analysis. To determine total and diffusible hydrogen, the influence of the following processes: chemical and mechanical zinc coating removal, sample cleaning with organic solvents, conditions for hydrogen absorption by electrolytic hydrogen charging, conditions of hydrogen desorption by storing the sample at room temperature, solid CO{sub 2} and at temperatures of the drier was analysed. The contribution of steel alloys towards

Measurements and predictors of on-road ultrafine particle concentrations and associated pollutants in Los Angeles

Energy Technology Data Exchange (ETDEWEB)

Fruin, S. [California Air Resources Board, Sacramento (United States); University of Southern California, Los Angeles (United States). Keck School of Medicine, Department of Preventive Medicine; Westerdahl, D.; Sax, T. [California Air Resources Board, Sacramento (United States); Sioutas, C. [University of Southern California, Los Angeles (United States). Civil and Environmental Engineering; Fine, P.M. [University of Southern California, Los Angeles (United States). Civil and Environmental Engineering; South Coast Air Quality Management District, Diamond Bar, CA (United States)

2008-01-15

Motor vehicles are the dominant source of oxides of nitrogen (NO{sub x}), particulate matter(PM), and certain air toxics (e.g., benzene, 1,3-butadiene) in urban areas. On roadways, motor vehicle-related pollutant concentrations are typically many times higher than ambient concentrations. Due to high air exchange rates typical of moving vehicles, this makes time spent in vehicles on roadways a major source of exposure. This paper presents on-road measurements for Los Angeles freeways and arterial roads taken from a zero-emission electric vehicle outfitted with real-time instruments. The objective was to characterize air pollutant concentrations on roadways and identify the factors associated with the highest concentrations. Our analysis demonstrated that on freeways, concentrations of ultrafine particles (UFPs), black carbon, nitric oxide, and PM-bound polycyclic aromatic hydrocarbons (PM-PAH) are generated primarily by diesel-powered vehicles, despite the relatively low fraction ({approx}6%) of diesel-powered vehicles on Los Angeles freeways. However, UFP concentrations on arterial roads appeared to be driven primarily by proximity to gasoline-powered vehicles undergoing hard accelerations. Concentrations were roughly one-third of those on freeways. By using a multiple regression model for the freeway measurements, we were able to explain 60-70% of the variability in concentrations of UFP, black carbon, nitric oxide, and PM-PAH using measures of diesel truck density and hour of day (as an indicator of wind speed). Freeway concentrations of these pollutants were also well correlated wth readily available annual average daily truck counts, potentially allowing improved population exposure estimates for epidemiology studies. Based on these roadway measurements and average driving time, it appears that 33-45% of total UFP exposure for Los Angeles residents occurs due to time spent traveling in vehicles. (author)

Measurements and predictors of on-road ultrafine particle concentrations and associated pollutants in Los Angeles

International Nuclear Information System (INIS)

Fruin, S.; Sioutas, C.

2008-01-01

Motor vehicles are the dominant source of oxides of nitrogen (NO x ), particulate matter(PM), and certain air toxics (e.g., benzene, 1,3-butadiene) in urban areas. On roadways, motor vehicle-related pollutant concentrations are typically many times higher than ambient concentrations. Due to high air exchange rates typical of moving vehicles, this makes time spent in vehicles on roadways a major source of exposure. This paper presents on-road measurements for Los Angeles freeways and arterial roads taken from a zero-emission electric vehicle outfitted with real-time instruments. The objective was to characterize air pollutant concentrations on roadways and identify the factors associated with the highest concentrations. Our analysis demonstrated that on freeways, concentrations of ultrafine particles (UFPs), black carbon, nitric oxide, and PM-bound polycyclic aromatic hydrocarbons (PM-PAH) are generated primarily by diesel-powered vehicles, despite the relatively low fraction (∼6%) of diesel-powered vehicles on Los Angeles freeways. However, UFP concentrations on arterial roads appeared to be driven primarily by proximity to gasoline-powered vehicles undergoing hard accelerations. Concentrations were roughly one-third of those on freeways. By using a multiple regression model for the freeway measurements, we were able to explain 60-70% of the variability in concentrations of UFP, black carbon, nitric oxide, and PM-PAH using measures of diesel truck density and hour of day (as an indicator of wind speed). Freeway concentrations of these pollutants were also well correlated wth readily available annual average daily truck counts, potentially allowing improved population exposure estimates for epidemiology studies. Based on these roadway measurements and average driving time, it appears that 33-45% of total UFP exposure for Los Angeles residents occurs due to time spent traveling in vehicles. (author)

Measurements and predictors of on-road ultrafine particle concentrations and associated pollutants in Los Angeles

Science.gov (United States)

Fruin, S.; Westerdahl, D.; Sax, T.; Sioutas, C.; Fine, P. M.

Motor vehicles are the dominant source of oxides of nitrogen (NO x), particulate matter (PM), and certain air toxics (e.g., benzene, 1,3-butadiene) in urban areas. On roadways, motor vehicle-related pollutant concentrations are typically many times higher than ambient concentrations. Due to high air exchange rates typical of moving vehicles, this makes time spent in vehicles on roadways a major source of exposure. This paper presents on-road measurements for Los Angeles freeways and arterial roads taken from a zero-emission electric vehicle outfitted with real-time instruments. The objective was to characterize air pollutant concentrations on roadways and identify the factors associated with the highest concentrations. Our analysis demonstrated that on freeways, concentrations of ultrafine particles (UFPs), black carbon, nitric oxide, and PM-bound polycyclic aromatic hydrocarbons (PM-PAH) are generated primarily by diesel-powered vehicles, despite the relatively low fraction (˜6%) of diesel-powered vehicles on Los Angeles freeways. However, UFP concentrations on arterial roads appeared to be driven primarily by proximity to gasoline-powered vehicles undergoing hard accelerations. Concentrations were roughly one-third of those on freeways. By using a multiple regression model for the freeway measurements, we were able to explain 60-70% of the variability in concentrations of UFP, black carbon, nitric oxide, and PM-PAH using measures of diesel truck density and hour of day (as an indicator of wind speed). Freeway concentrations of these pollutants were also well correlated with readily available annual average daily truck counts, potentially allowing improved population exposure estimates for epidemiology studies. Based on these roadway measurements and average driving time, it appears that 33-45% of total UFP exposure for Los Angeles residents occurs due to time spent traveling in vehicles.

Measurements of ice nucleating particle concentrations at 242 K in the free troposphere

Science.gov (United States)

Lacher, L.; Lohmann, U.; Boose, Y.; Zipori, A.; Herrmann, E.; Bukowiecki, N.; Steinbacher, M.; Gute, E.; Kanji, Z. A.

2017-12-01

Clouds containing ice play an important role in the Earth's system, but some fundamental knowledge on their formation and further development is still missing. The phase change from vapor or liquid to ice in the atmosphere can occur heterogeneously in the presence of ice nucleating particles (INPs) at temperatures warmer, and supersaturations lower than required for homogeneous freezing. Only a small fraction of particles in an environment relevant for the occurrence of ice- and mixed-phase clouds are INPs, and their identification and quantification remains challenging. We measure INP concentrations with the ETH Horizontal Ice Nucleation Chamber (HINC) at the High Altitude Research Station Jungfraujoch (JFJ) during several field campaigns in different seasons and years. The measurements are performed at 242 K and above water saturation, representing ice- and mixed-phase clouds conditions. Due to its elevation of 3580 m a.s.l. the site encounters mostly free tropospheric conditions, and is influenced by boundary layer injections up to 80% of the time in summer. JFJ regularly encounters Saharan dust events and receives air masses of marine origin, which can both occur within the free troposphere. Our measurements show that INP concentrations in the free troposphere do not follow a seasonal cycle. They are remarkably constant, with concentrations from 0.5 - 8 L-1 (interquartile range), which compares well to measurements performed under the same conditions at another location within the free troposphere, the Izaña Atmospheric Research Station in Tenerife. At JFJ, correlations with parameters of physical properties of ambient particles, meteorology and air mass characteristics do not show a single best estimator to predict INP concentrations, emphasizing the complexity of ice nucleation in the free troposphere. Increases in INP concentrations of a temporary nature were observed in the free troposphere during Saharan dust events and marine air mass influence, which

Seasonal and spatial variations of rare earth elements in rainwaters, river waters and total suspended particles in air in South Korea

International Nuclear Information System (INIS)

Ryu, J.S.; Lee, K.S.; Lee, S.G.; Lee, D.; Chang, H.W.

2007-01-01

In order to investigate the seasonal and spatial variations of rare earth element (REE) concentrations in natural waters in the central part of South Korea, rain and river waters were collected during 2003-2004. Total suspended particles (TSP) in air were also sampled to investigate the effect of the Asian dust (the Yellow sand) on the chemistry of rainwaters. All samples showed that the absolute concentrations of the light REEs (LREEs) were higher than those of the heavy REEs (HREEs). The post-Archean Australian shale (PAAS)-normalized REE patterns indicate that the REEs in TSP and rainwaters were affected by Asian dust and anthropogenic contaminant, whereas those of river waters were mainly controlled by the geology of their drainage basin and seasonal changes in water regime. The calculated fluxes and yields of total REEs (REEs plus Y) in the South Han River were much greater than those in the North Han River due to the more widespread distribution of sedimentary rocks in the drainage area and more efficient chemical weathering

Fractionation and characterization of particles simulating wear of total joint replacement (TJR) following ASTM standards.

Science.gov (United States)

Saha, Subrata; Musib, Mrinal

2011-01-01

Reactions of bone cells to orthopedic wear debris produced by the articulating motion of total joint replacements (TJRs) are largely responsible for the long-term failure of such replacements. Metal and polyethylene (PE) wear particles isolated from fluids from total joint simulators, as well as particles that are fabricated by other methods, are widely used to study such in vitro cellular response. Prior investigations have revealed that cellular response to wear debris depends on the size, shape, and dose of the particles. Hence, to have a better understanding of the wear-mediated osteolytic process it is important that these particles are well characterized and clinically relevant, both qualitatively, and quantitatively. In this study we have fractionated both ultra-high molecular weight polyethylene (UHMWPE) and Ti particles, into micron (1.0-10.0 μm), submicron (0.2-1.0 μm), and nanoparticle (0.01-0.2 μm) fractions, and characterized them based on the following size-shape descriptors as put forth in ASTM F1877: i) equivalent circle diameter (ECD), ii) aspect ratio (AR), iii) elongation (E), iv) roundness (R), and v) form factor (FF). The mean (± SD) ECDs (in μm) for micron, submicron, and nanoparticles of UHMWPE were 1.652 ± 0.553, 0.270 ± 0.180, and 0.061 ± 0.035, respectively, and for Ti were 1.894 ± 0.667, 0.278 ± 0.180, and 0.055 ± 0.029, respectively. The values for other descriptors were similar (no statistically significant difference). The nanofraction particles were found to be more sphere-like (higher R and FF values, and lower E and AR values) as compared to larger particles. Future experiments will involve use of these well characterized particles for in vitro studies.

Factors affecting color strength of printing on film-coated tablets by UV laser irradiation: TiO2 particle size, crystal structure, or concentration in the film, and the irradiated UV laser power.

Science.gov (United States)

Hosokawa, Akihiro; Kato, Yoshiteru

2011-08-01

The purpose of this article is to study factors affecting color strength of printing on film-coated tablets by ultraviolet (UV) laser irradiation: particle size, crystal structure, or concentration of titanium dioxide (TiO2) in film, and irradiated UV laser power. Hydroxypropylmethylcellulose films containing 4.0% of TiO2, of which BET particle sizes were ranging from 126.1 to 219.8 nm, were irradiated 3.14W of UV laser at a wavelength 355 nm to study effects of TiO2 particle size and crystal structure on the printing. The films containing TiO2 concentration ranging from 1.0 to 7.7% were irradiated 3.14 or 5.39W of the UV laser to study effect of TiO2 concentration on the printing. The film containing 4.0% of TiO2, was irradiated the UV laser up to 6.42W to study effect of the UV laser power on the printing. The color strength of the printed films was estimated by a spectrophotometer as total color difference (dE). Particle size, crystal structure, and concentration of TiO2 in the films did not affect the printing. In the relationship between the irradiated UV laser power and dE, there found an inflection point (1.6W). When the UV laser power was below 1.6W, the films were not printed. When it was beyond the point, total color difference increased linearly in proportion with the irradiated laser power. The color strength of the printing on film was not changed by TiO2 particle size, crystal structure, and concentration, but could be controlled by regulating the irradiated UV laser power beyond the inflection point.

Source apportionment of ambient particle number concentrations in central Los Angeles using positive matrix factorization (PMF

Directory of Open Access Journals (Sweden)

M. H. Sowlat

2016-04-01

Full Text Available In this study, the positive matrix factorization (PMF receptor model (version 5.0 was used to identify and quantify major sources contributing to particulate matter (PM number concentrations, using PM number size distributions in the range of 13 nm to 10 µm combined with several auxiliary variables, including black carbon (BC, elemental and organic carbon (EC/OC, PM mass concentrations, gaseous pollutants, meteorological, and traffic counts data, collected for about 9 months between August 2014 and 2015 in central Los Angeles, CA. Several parameters, including particle number and volume size distribution profiles, profiles of auxiliary variables, contributions of different factors in different seasons to the total number concentrations, diurnal variations of each of the resolved factors in the cold and warm phases, weekday/weekend analysis for each of the resolved factors, and correlation between auxiliary variables and the relative contribution of each of the resolved factors, were used to identify PM sources. A six-factor solution was identified as the optimum for the aforementioned input data. The resolved factors comprised nucleation, traffic 1, traffic 2 (with a larger mode diameter than traffic 1 factor, urban background aerosol, secondary aerosol, and soil/road dust. Traffic sources (1 and 2 were the major contributor to PM number concentrations, collectively making up to above 60 % (60.8–68.4 % of the total number concentrations during the study period. Their contribution was also significantly higher in the cold phase compared to the warm phase. Nucleation was another major factor significantly contributing to the total number concentrations (an overall contribution of 17 %, ranging from 11.7 to 24 %, with a larger contribution during the warm phase than in the cold phase. The other identified factors were urban background aerosol, secondary aerosol, and soil/road dust, with relative contributions of approximately 12�

High concentrations of coarse particles emitted from a cattle feeding operation

Directory of Open Access Journals (Sweden)

N. Hiranuma

2011-08-01

Full Text Available Housing roughly 10 million head of cattle in the United States alone, open air cattle feedlots represent a significant but poorly constrained source of atmospheric particles. Here we present a comprehensive characterization of physical and chemical properties of particles emitted from a large representative cattle feedlot in the Southwest United States. In the summer of 2008, measurements and samplings were conducted at the upwind and downwind edges of the facility. A series of far-field measurements and samplings was also conducted 3.5 km north of the facility. Two instruments, a GRIMM Sequential Mobility Particle Sizer (SMPS and a GRIMM Portable Aerosol Spectrometer (PAS, were used to measure particle size distributions over the range of 0.01 to 25 μm diameter. Raman microspectroscopy was used to determine the chemical composition of particles on a single particle basis. Volume size distributions of dust were dominated by coarse mode particles. Twenty-four hour averaged concentrations of PM₁₀ (particulate matter with a diameter of 10 μm or less were as high as 1200 μg m⁻³ during the campaign. The primary constituents of the particulate matter were carbonaceous materials, such as humic acid, water soluble organics, and less soluble fatty acids, including stearic acid and tristearin. A significant fraction of the organic particles was present in internal mixtures with salts. Basic characteristics such as size distribution and composition of agricultural aerosols were found to be different than the properties of those found in urban and semi-urban aerosols. Failing to account for such differences may lead to errors in estimates of aerosol effects on local air quality, visibility, and public health.

No difference in in vivo polyethylene wear particles between oxidized zirconium and cobalt-chromium femoral component in total knee arthroplasty.

Science.gov (United States)

Minoda, Yukihide; Hata, Kanako; Iwaki, Hiroyoshi; Ikebuchi, Mitsuhiko; Hashimoto, Yusuke; Inori, Fumiaki; Nakamura, Hiroaki

2014-03-01

Polyethylene wear particle generation is one of the most important factors affecting mid- to long-term results of total knee arthroplasties. Oxidized zirconium was introduced as a material for femoral components to reduce polyethylene wear generation. However, an in vivo advantage of oxidized zirconium on polyethylene wear particle generation is still controversial. The purpose of this study was to compare in vivo polyethylene wear particles between oxidized zirconium total knee prosthesis and conventional cobalt-chromium (Co-Cr) total knee prosthesis. Synovial fluid was obtained from the knees of 6 patients with oxidized zirconium total knee prosthesis and from 6 patients with conventional cobalt-chromium (Co-Cr) total knee prosthesis 12 months after the operation. Polyethylene particles were isolated and examined using a scanning electron microscope and image analyser. Total number of particles in each knee was 3.3 ± 1.3 × 10(7) in the case of oxidized zirconium (mean ± SD) and 3.4 ± 1.2 × 10(7) in that of Co-Cr (n.s.). The particle size (equivalent circle diameter) was 0.8 ± 0.3 μm in the case of oxidized zirconium and 0.6 ± 0.1 μm in that of Co-Cr (n.s.). The particle shape (aspect ratio) was 1.4 ± 0.0 in the case of oxidized zirconium and 1.4 ± 0.0 in that of metal Co-Cr (n.s). Although newly introduced oxidized zirconium femoral component did not reduce the in vivo polyethylene wear particles in early clinical stage, there was no adverse effect of newly introduced material. At this moment, there is no need to abandon oxidized zirconium femoral component. However, further follow-up of polyethylene wear particle generation should be performed to confirm the advantage of the oxidized zirconium femoral component. Therapeutic study, Level III.

Harmonisation of nanoparticle concentration measurements using GRIMM and TSI scanning mobility particle sizers

International Nuclear Information System (INIS)

Joshi, Manish; Sapra, B. K.; Khan, Arshad; Tripathi, S. N.; Shamjad, P. M.; Gupta, Tarun; Mayya, Y. S.

2012-01-01

Regional studies focusing on the role of atmospheric nanoparticles in climate change have gained impetus in the last decade. Several multi-institutional studies involving measurement of nanoparticles with several kinds of instruments are on the rise. It is important to harmonize these measurements as the instruments may work on different techniques or principles and are developed by different manufacturers. Scanning mobility particle sizers (SMPS) are often used to measure size distribution of nanoparticles in the airborne phase. Two such commercially available instruments namely, GRIMM and TSI-SMPS have been compared for ambient and laboratory generated conditions. A stand-alone condensation particle counter (CPC) of TSI make was used as a reference for particle concentration measurements. The consistency of the results in terms of mean size and geometric standard deviation was seen to be excellent for both the SMPSs, with GRIMM always showing slightly (approximately 10 %) lower mean size. The integrated number concentration from GRIMM-SMPS was seen to be closer to stand-alone reference CPC compared to TSI-SMPS, for an ambient overnight comparison. However, a concentration-dependent response, i.e. the variations between the two instruments increasing with the concentration, was observed and possible reasons for this have been suggested. A separate experiment was performed for studying the modifying effect of diffusion dryer and sheath air dryer on the measured aerosol size spectra. A significant hygroscopic growth was noted when diffusion dryer was attached to one of the SMPS. The introduction of sheath air dryer in GRIMM-SMPS produced a significant shift towards lower mean size. These results have been compared and discussed with the recent inter-comparison results to strengthen and harmonize the measurement protocols.

Harmonisation of nanoparticle concentration measurements using GRIMM and TSI scanning mobility particle sizers

Science.gov (United States)

Joshi, Manish; Sapra, B. K.; Khan, Arshad; Tripathi, S. N.; Shamjad, P. M.; Gupta, Tarun; Mayya, Y. S.

2012-12-01

Regional studies focusing on the role of atmospheric nanoparticles in climate change have gained impetus in the last decade. Several multi-institutional studies involving measurement of nanoparticles with several kinds of instruments are on the rise. It is important to harmonize these measurements as the instruments may work on different techniques or principles and are developed by different manufacturers. Scanning mobility particle sizers (SMPS) are often used to measure size distribution of nanoparticles in the airborne phase. Two such commercially available instruments namely, GRIMM and TSI-SMPS have been compared for ambient and laboratory generated conditions. A stand-alone condensation particle counter (CPC) of TSI make was used as a reference for particle concentration measurements. The consistency of the results in terms of mean size and geometric standard deviation was seen to be excellent for both the SMPSs, with GRIMM always showing slightly (approximately 10 %) lower mean size. The integrated number concentration from GRIMM-SMPS was seen to be closer to stand-alone reference CPC compared to TSI-SMPS, for an ambient overnight comparison. However, a concentration-dependent response, i.e. the variations between the two instruments increasing with the concentration, was observed and possible reasons for this have been suggested. A separate experiment was performed for studying the modifying effect of diffusion dryer and sheath air dryer on the measured aerosol size spectra. A significant hygroscopic growth was noted when diffusion dryer was attached to one of the SMPS. The introduction of sheath air dryer in GRIMM-SMPS produced a significant shift towards lower mean size. These results have been compared and discussed with the recent inter-comparison results to strengthen and harmonize the measurement protocols.

Submicron particle mass concentrations and sources in the Amazonian wet season (AMAZE-08)

Energy Technology Data Exchange (ETDEWEB)

Chen, Q.; Farmer, D. K.; Rizzo, L. V.; Pauliqueivis, T.; Kuwata, Mikinori; Karl, Thomas G.; Guenther, Alex B.; Allan, James D.; Coe, H.; Andreae, M. O.; Poeschl, U.; Jiminez, J. L.; Artaxo, Paulo; Martin, Scot T.

2015-01-01

Real-time mass spectra of non-refractory component of submicron aerosol particles were recorded in a tropical rainforest in the central Amazon basin during the wet season of 2008, as a part of the Amazonian Aerosol Characterization Experiment (AMAZE-08). Organic components accounted on average for more than 80% of the non-refractory submicron particle mass concentrations during the period of measurements. Ammonium was present in sufficient quantities to halfway neutralize sulfate. In this acidic, isoprene-dominated, low-NOx environment the high-resolution mass spectra as well as mass closures with ion chromatography measurements did not provide evidence for significant contributions of organosulfate species, at least at concentrations above uncertainty levels. Positive-matrix factorization of the time series of particle mass spectra identified four statistical factors to account for the variance of the signal intensities of the organic constituents: a factor HOA having a hydrocarbon-like signature and identified as regional emissions of primary organic material, a factor OOA-1 associated with fresh production of secondary organic material by a mechanism of BVOC oxidation followed by gas-to-particle conversion, a factor OOA-2 consistent with reactive uptake of isoprene oxidation products, especially epoxydiols by acidic particles, and a factor OOA-3 associated with long range transport and atmospheric aging. The OOA-1, -2, and -3 factors had progressively more oxidized signatures. Diameter-resolved mass spectral markers also suggested enhanced reactive uptake of isoprene oxidation products to the accumulation mode for the OOA-2 factor, and such size partitioning can be indicative of in-cloud process. The campaign-average factor loadings were in a ratio of 1.1:1.0 for the OOA-1 compared to the OOA-2 pathway, suggesting the comparable importance of gas-phase compared to particle-phase (including cloud waters) production pathways of secondary organic material during

Emulsion Polymerization of Etyl Acrylate: The Effect of Surfactant, Initiator Concentration and PolymerizationTechnique on Particle Size Distribution

Directory of Open Access Journals (Sweden)

Nitri Arinda

2009-04-01

Full Text Available Emulsion polymerization was conducted using ethyl acrylate monomer. Theeffect of sodium lauryl sulfate concentration, ammonium persulfate concentration, the various of polymerizationtechniques and feeding time to the conversion, particle size and its distribution were observed. The purpose of thisresearch is to obtain the optimum condition of ethyl acrylate homopolymer with particle size around 100 nm, to get theparticle size distribution monodisperse and to get solid content value of the experiment closed to its theoretical value.The optimum condition then could be applied in shell polymerization of core-shell polymers. The results of the researchshowed that semicontinuous technique obtained optimum sodium lauryl sulfate concentration at 20 CMC (criticalmicelle concentration and ammonium persulfate concentration is 3%. By using batch technique that the biggestparticle size is 123 nm with conversion 95.8% and monodisperse. The shorter of feeding time the more monomer ofethyl acrylate being polymerized, it is showed by the higher conversion up to 94.4% and the bigger particle size is107.9 nm.

Distribution of concentration of coarse particle-water mixture in horizontal smooth pipe

Czech Academy of Sciences Publication Activity Database

Vlasák, Pavel; Chára, Zdeněk; Konfršt, Jiří; Krupička, Jan

2016-01-01

Roč. 94, č. 6 (2016), s. 1040-1047 ISSN 0008-4034 R&D Projects: GA ČR GAP105/10/1574 Institutional support: RVO:67985874 Keywords : coarse particle-water mixture * gamma-ray radiometry * concentration distribution * horizontal conveying Subject RIV: BK - Fluid Dynamics Impact factor: 1.356, year: 2016

Distribution of concentration of coarse particle-water mixture in horizontal smooth pipe

Czech Academy of Sciences Publication Activity Database

Vlasák, Pavel; Chára, Zdeněk; Konfršt, Jiří; Krupička, Jan

2016-01-01

Roč. 94, č. 6 (2016), s. 1040-1047 ISSN 0008-4034 R&D Projects: GA ČR GAP105/10/1574 Institutional support: RVO:67985874 Keywords : coarse particle- water mixture * gamma-ray radiometry * concentration distribution * horizontal conveying Subject RIV: BK - Fluid Dynamics Impact factor: 1.356, year: 2016

Short-term exposure with high concentrations of pristine microplastic particles leads to immobilisation of Daphnia magna.

Science.gov (United States)

Rehse, Saskia; Kloas, Werner; Zarfl, Christiane

2016-06-01

Recent studies revealed that freshwaters are not only polluted by chemicals, but also by persistent synthetic material like microplastics (plastic particles pollutants or release additives. Although there is rising concern about the pollution of freshwaters by microplastics, knowledge about their potential effects on organisms is limited. For a better understanding of their risks, it is crucial to unravel which characteristics influence their effects on organisms. Analysing effects by the mere particles is the first step before including more complex interactions e.g. with associated chemicals. The aim of this study was to analyse potential physical effects of microplastics on one representative organism for limnic zooplankton (Daphnia magna). We investigated whether microplastics can be ingested and whether their presence causes adverse effects after short-term exposure. Daphnids were exposed for up to 96 h to 1-μm and 100-μm polyethylene particles at concentrations between 12.5 and 400 mg L(-1). Ingestion of 1-μm particles led to immobilisation increasing with dose and time with an EC50 of 57.43 mg L(-1) after 96 h. 100-μm particles that could not be ingested by the daphnids had no observable effects. These results underline that, considering high concentrations, microplastic particles can already induce adverse effects in limnic zooplankton. Although it needs to be clarified if these concentrations can be found in the environment these results are a basis for future impact analysis, especially in combination with associated chemicals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Aerosol particle mixing state, refractory particle number size distributions and emission factors in a polluted urban environment: Case study of Metro Manila, Philippines

Science.gov (United States)

Kecorius, Simonas; Madueño, Leizel; Vallar, Edgar; Alas, Honey; Betito, Grace; Birmili, Wolfram; Cambaliza, Maria Obiminda; Catipay, Grethyl; Gonzaga-Cayetano, Mylene; Galvez, Maria Cecilia; Lorenzo, Genie; Müller, Thomas; Simpas, James B.; Tamayo, Everlyn Gayle; Wiedensohler, Alfred

2017-12-01

Ultrafine soot particles (black carbon, BC) in urban environments are related to adverse respiratory and cardiovascular effects, increased cases of asthma and premature deaths. These problems are especially pronounced in developing megacities in South-East Asia, Latin America, and Africa, where unsustainable urbanization ant outdated environmental protection legislation resulted in severe degradation of urban air quality in terms of black carbon emission. Since ultrafine soot particles do often not lead to enhanced PM10 and PM2.5 mass concentration, the risks related to ultrafine particle pollution may therefore be significantly underestimated compared to the contribution of secondary aerosol constituents. To increase the awareness of the potential toxicological relevant problems of ultrafine black carbon particles, we conducted a case study in Metro Manila, the capital of the Philippines. Here, we present a part of the results from a detailed field campaign, called Manila Aerosol Characterization Experiment (MACE, 2015). Measurements took place from May to June 2015 with the focus on the state of mixing of aerosol particles. The results were alarming, showing the abundance of externally mixed refractory particles (soot proxy) at street site with a maximum daily number concentration of approximately 15000 #/cm3. That is up to 10 times higher than in cities of Western countries. We also found that the soot particle mass contributed from 55 to 75% of total street site PM2.5. The retrieved refractory particle number size distribution appeared to be a superposition of 2 ultrafine modes at 20 and 80 nm with a corresponding contribution to the total refractory particle number of 45 and 55%, respectively. The particles in the 20 nm mode were most likely ash from metallic additives in lubricating oil, tiny carbonaceous particles and/or nucleated and oxidized organic polymers, while bigger ones (80 nm) were soot agglomerates. To the best of the authors' knowledge, no other

A high gradient and strength bioseparator with nano-sized immunomagnetic particles for specific separation and efficient concentration of E. coli O157:H7

International Nuclear Information System (INIS)

Lin, Jianhan; Li, Min; Li, Yanbin; Chen, Qi

2015-01-01

Sample pretreatment is a key to rapid screening of pathogens for prevention and control of foodborne diseases. Magnetic immunoseparation is a specific method based on antibody–antigen reaction to capture the target bacteria and concentrate them in a smaller-volume buffer. The use of nano-sized magnetic particles could improve the separation efficiency of bacteria but require much higher gradient and strength magnetic field. In this study, a strong magnetic bioseparator with a mean field strength of 1.35 T and a mean gradient of 90 T/m was developed with the use of the 30 nm and 180 nm magnetic particles to specifically separate and efficiently concentrate foodborne bacterial pathogens using Escherichia coli O157:H7 as a model bacterium. The polyclonal antibodies against E. coli were evaluated using Dot ELISA analysis for their good affinity with the target bacteria and then used to modify the surface of the magnetic nanoparticles by 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl) method and streptavidin-biotin binding. The magnetic particle concentrations were optimized to be 40 µg/ml and 100 µg/ml for the 30 nm and 180 nm particles, respectively, the immunoreaction time was optimized to be 45 min for both sizes of particles, and the separation times were optimized to be 60 min and 2 min for the 30 nm and 180 nm particles, respectively. The total magnetic separation time was 2 h and 1 h for the 30 nm and 180 nm particles, respectively. The experimental results demonstrated that the bioseparator with the use of either 30 nm or 180 nm immunomagnetic particles could achieve a separation efficiency of >90% for E. coli O157:H7 at the concentrations ranging from 10 2 to 10 5 cfu/ml. No obvious interferences from non-target foodborne pathogens, such as SalmonellaTyphimurium and Listeria innocua, were found. For overall consideration of the consuming time, the cost, and the separation efficiency, the 180 nm magnetic particles are practical for

A high gradient and strength bioseparator with nano-sized immunomagnetic particles for specific separation and efficient concentration of E. coli O157:H7

Energy Technology Data Exchange (ETDEWEB)

Lin, Jianhan, E-mail: jianhan@cau.edu.cn [Ministry of Agriculture Key Laboratory of Agricultural Information Acquisition Technology (Beijing), 17 East Tsinghua Road, China Agricultural University, Mailbox 125, Beijing 100083 (China); Li, Min [College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058 (China); Li, Yanbin [College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058 (China); Department of Biological and Agricultural Engineering, University of Arkansas, Fayetteville, AR 72701 (United States); Chen, Qi [Modern Precision Agriculture System Integration Research Key Laboratory of Ministry of Education, China Agricultural University, Beijing 100083 (China)

2015-03-15

Sample pretreatment is a key to rapid screening of pathogens for prevention and control of foodborne diseases. Magnetic immunoseparation is a specific method based on antibody–antigen reaction to capture the target bacteria and concentrate them in a smaller-volume buffer. The use of nano-sized magnetic particles could improve the separation efficiency of bacteria but require much higher gradient and strength magnetic field. In this study, a strong magnetic bioseparator with a mean field strength of 1.35 T and a mean gradient of 90 T/m was developed with the use of the 30 nm and 180 nm magnetic particles to specifically separate and efficiently concentrate foodborne bacterial pathogens using Escherichia coli O157:H7 as a model bacterium. The polyclonal antibodies against E. coli were evaluated using Dot ELISA analysis for their good affinity with the target bacteria and then used to modify the surface of the magnetic nanoparticles by 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl) method and streptavidin-biotin binding. The magnetic particle concentrations were optimized to be 40 µg/ml and 100 µg/ml for the 30 nm and 180 nm particles, respectively, the immunoreaction time was optimized to be 45 min for both sizes of particles, and the separation times were optimized to be 60 min and 2 min for the 30 nm and 180 nm particles, respectively. The total magnetic separation time was 2 h and 1 h for the 30 nm and 180 nm particles, respectively. The experimental results demonstrated that the bioseparator with the use of either 30 nm or 180 nm immunomagnetic particles could achieve a separation efficiency of >90% for E. coli O157:H7 at the concentrations ranging from 10{sup 2} to 10{sup 5} cfu/ml. No obvious interferences from non-target foodborne pathogens, such as SalmonellaTyphimurium and Listeria innocua, were found. For overall consideration of the consuming time, the cost, and the separation efficiency, the 180 nm magnetic particles are

Long-term cloud condensation nuclei number concentration, particle number size distribution and chemical composition measurements at regionally representative observatories

Science.gov (United States)

Schmale, Julia; Henning, Silvia; Decesari, Stefano; Henzing, Bas; Keskinen, Helmi; Sellegri, Karine; Ovadnevaite, Jurgita; Pöhlker, Mira L.; Brito, Joel; Bougiatioti, Aikaterini; Kristensson, Adam; Kalivitis, Nikos; Stavroulas, Iasonas; Carbone, Samara; Jefferson, Anne; Park, Minsu; Schlag, Patrick; Iwamoto, Yoko; Aalto, Pasi; Äijälä, Mikko; Bukowiecki, Nicolas; Ehn, Mikael; Frank, Göran; Fröhlich, Roman; Frumau, Arnoud; Herrmann, Erik; Herrmann, Hartmut; Holzinger, Rupert; Kos, Gerard; Kulmala, Markku; Mihalopoulos, Nikolaos; Nenes, Athanasios; O'Dowd, Colin; Petäjä, Tuukka; Picard, David; Pöhlker, Christopher; Pöschl, Ulrich; Poulain, Laurent; Prévôt, André Stephan Henry; Swietlicki, Erik; Andreae, Meinrat O.; Artaxo, Paulo; Wiedensohler, Alfred; Ogren, John; Matsuki, Atsushi; Yum, Seong Soo; Stratmann, Frank; Baltensperger, Urs; Gysel, Martin

2018-02-01

Aerosol-cloud interactions (ACI) constitute the single largest uncertainty in anthropogenic radiative forcing. To reduce the uncertainties and gain more confidence in the simulation of ACI, models need to be evaluated against observations, in particular against measurements of cloud condensation nuclei (CCN). Here we present a data set - ready to be used for model validation - of long-term observations of CCN number concentrations, particle number size distributions and chemical composition from 12 sites on 3 continents. Studied environments include coastal background, rural background, alpine sites, remote forests and an urban surrounding. Expectedly, CCN characteristics are highly variable across site categories. However, they also vary within them, most strongly in the coastal background group, where CCN number concentrations can vary by up to a factor of 30 within one season. In terms of particle activation behaviour, most continental stations exhibit very similar activation ratios (relative to particles > 20 nm) across the range of 0.1 to 1.0 % supersaturation. At the coastal sites the transition from particles being CCN inactive to becoming CCN active occurs over a wider range of the supersaturation spectrum. Several stations show strong seasonal cycles of CCN number concentrations and particle number size distributions, e.g. at Barrow (Arctic haze in spring), at the alpine stations (stronger influence of polluted boundary layer air masses in summer), the rain forest (wet and dry season) or Finokalia (wildfire influence in autumn). The rural background and urban sites exhibit relatively little variability throughout the year, while short-term variability can be high especially at the urban site. The average hygroscopicity parameter, κ, calculated from the chemical composition of submicron particles was highest at the coastal site of Mace Head (0.6) and lowest at the rain forest station ATTO (0.2-0.3). We performed closure studies based on κ-Köhler theory

Determination of serum free thyroxine concentration (FT4) by means of fT4-fraction and total thyroxine concentration

International Nuclear Information System (INIS)

Passath, A.; Leb, G.

1985-01-01

A new equilibrium assay for the determination of serum free thyroxine was evaluated in 514 patients. The assay comprises a two-vial-procedure to measure total thyroxine and free thyroxine fraction by use of monoclonal antibodies. Free thyroxine concentrations are calculated from fT 4 -fraction and total thyroxine concentration readings. In euthyroidism the average free thyroxine fraction (%fT 4 ) was 0.011%, in hyperthyroidism this fraction was elevated, in hypothyroidism it was below normal. In patients with TBG anomalies, TBG values were inversely correlated with fT 4 fraction readings. The 'euthyroid reference range' of FT 4 (SPAC ET) was between 0.70 to 1.78ng/dl. This euthyroid range of FT 4 was determined from TT 4 concentrations measured by T 4 -RIA (SPAC T 4 MONO) which were 30% above TT 4 values measured by conventional T 4 -RIA (SPAC T 4 POLY; polyclonal antibodies). However, a different euthyroid range of FT 4 between 0.55 to 1.30 ng/dl was observed as well as by other investigators when conventional T 4 -RIA measurements were used for calculation of FT 4 values. Our results indicate that calculated FT 4 concentration values are highly dependent on the methods used for determination of total thyroxine concentrations. Precision and reproducability of this two vial equilibrium assay did not meet the requirements mandatory for the application as a clinical routine diagnostic procedure, and its general use for this purpose can as yet not be recommended. (Author)

Total mercury concentrations in lionfish (Pterois volitans/miles) from the Florida Keys National Marine Sanctuary, USA.

Science.gov (United States)

Huge, Dane H; Schofield, Pamela J; Jacoby, Charles A; Frazer, Thomas K

2014-01-15

Strategies to control invasive lionfish in the western Atlantic and Caribbean are likely to include harvest and consumption. Until this report, total mercury concentrations had been documented only for lionfish from Jamaica, and changes in concentrations with increasing fish size had not been evaluated. In the Florida Keys, total mercury concentrations in dorsal muscle tissue from 107 lionfish ranged from 0.03 to 0.48 ppm, with all concentrations being less than the regulatory threshold for limited consumption. Mercury concentrations did not vary consistently with standard lengths or wet weights of lionfish. In 2010, lionfish from the upper Keys had mean concentrations that were 0.03-0.04 ppm higher than lionfish from the middle Keys, but mean concentrations did not differ consistently among years and locations. Overall, total mercury concentrations in lionfish were lower than those in several predatory fishes that support commercial and recreational fisheries in Florida. Published by Elsevier Ltd.

Mean total arsenic concentrations in chicken 1989-2000 and estimated exposures for consumers of chicken.

OpenAIRE

Lasky, Tamar; Sun, Wenyu; Kadry, Abdel; Hoffman, Michael K

2004-01-01

The purpose of this study was to estimate mean concentrations of total arsenic in chicken liver tissue and then estimate total and inorganic arsenic ingested by humans through chicken consumption. We used national monitoring data from the Food Safety and Inspection Service National Residue Program to estimate mean arsenic concentrations for 1994-2000. Incorporating assumptions about the concentrations of arsenic in liver and muscle tissues as well as the proportions of inorganic and organic a...

Brominated flame retardants in the urban atmosphere of Northeast China: Concentrations, temperature dependence and gas-particle partitioning

Energy Technology Data Exchange (ETDEWEB)

Qi, Hong; Li, Wen-Long; Liu, Li-Yan; Song, Wei-Wei; Ma, Wan-Li, E-mail: mawanli002@163.com; Li, Yi-Fan, E-mail: ijrc_pts_paper@yahoo.com

2014-09-01

57 pairs of air samples (gas and particle phases) were collected using a high volume air sampler in a typical city of Northeast China. Brominated flame retardants (BFRs) including 13 polybrominated diphenyl ethers (PBDEs, including BDEs 17, 28, 47, 49, 66, 85, 99, 100, 138, 153, 154, 183, and 209) and 9 alternative BFRs (p-TBX, PBBZ, PBT, PBEB, DPTE, HBBZ, γ-HBCD, BTBPE, and DBDPE) were analyzed. The annual average total concentrations of the 13 PBDEs and the 9 alternative BFRs were 69 pg/m{sup 3} and 180 pg/m{sup 3}, respectively. BDE 209 and γ-HBCD were the dominant congeners, according to the one-year study. The partial pressure of BFRs in the gas phase was significantly correlated with the ambient temperature, except for BDE 85, γ-HBCD and DBDPE, indicating the important influence of ambient temperature on the behavior of BFRs in the atmosphere. It was found that the gas–particle partitioning coefficients (logK{sub p}) for most low molecular weight BFRs were highly temperature dependent as well. Gas–particle partitioning coefficients (logK{sub p}) also correlated with the sub-cooled liquid vapor pressure (logP{sub L}{sup o}). Our results indicated that absorption into organic matter is the main control mechanism for the gas–particle partitioning of atmospheric PBDEs. - Highlights: • Both PBDEs and alternative BFRs were analyzed in the atmosphere of Northeast China. • Partial pressure of BFRs was significantly correlated with the ambient temperature. • A strong temperature dependence of gas-particle partitioning was found. • Absorption into organic matter was the control mechanism for G-P partitioning.

Characterization of a catalyst-based conversion technique to measure total particulate nitrogen and organic carbon and comparison to a particle mass measurement instrument

Science.gov (United States)

Stockwell, Chelsea E.; Kupc, Agnieszka; Witkowski, Bartłomiej; Talukdar, Ranajit K.; Liu, Yong; Selimovic, Vanessa; Zarzana, Kyle J.; Sekimoto, Kanako; Warneke, Carsten; Washenfelder, Rebecca A.; Yokelson, Robert J.; Middlebrook, Ann M.; Roberts, James M.

2018-05-01

The chemical composition of aerosol particles is a key aspect in determining their impact on the environment. For example, nitrogen-containing particles impact atmospheric chemistry, air quality, and ecological N deposition. Instruments that measure total reactive nitrogen (Nr = all nitrogen compounds except for N2 and N2O) focus on gas-phase nitrogen and very few studies directly discuss the instrument capacity to measure the mass of Nr-containing particles. Here, we investigate the mass quantification of particle-bound nitrogen using a custom Nr system that involves total conversion to nitric oxide (NO) across platinum and molybdenum catalysts followed by NO-O3 chemiluminescence detection. We evaluate the particle conversion of the Nr instrument by comparing to mass-derived concentrations of size-selected and counted ammonium sulfate ((NH4)2SO4), ammonium nitrate (NH4NO3), ammonium chloride (NH4Cl), sodium nitrate (NaNO3), and ammonium oxalate ((NH4)2C2O4) particles determined using instruments that measure particle number and size. These measurements demonstrate Nr-particle conversion across the Nr catalysts that is independent of particle size with 98 ± 10 % efficiency for 100-600 nm particle diameters. We also show efficient conversion of particle-phase organic carbon species to CO2 across the instrument's platinum catalyst followed by a nondispersive infrared (NDIR) CO2 detector. However, the application of this method to the atmosphere presents a challenge due to the small signal above background at high ambient levels of common gas-phase carbon compounds (e.g., CO2). We show the Nr system is an accurate particle mass measurement method and demonstrate its ability to calibrate particle mass measurement instrumentation using single-component, laboratory-generated, Nr-containing particles below 2.5 µm in size. In addition we show agreement with mass measurements of an independently calibrated online particle-into-liquid sampler directly coupled to the

Evaluating Ice Nucleating Particle Concentrations From Prognostic Dust Minerals in an Earth System Model

Science.gov (United States)

Perlwitz, J. P.; Knopf, D. A.; Fridlind, A. M.; Miller, R. L.; Pérez García-Pando, C.; DeMott, P. J.

2016-12-01

The effect of aerosol particles on the radiative properties of clouds, the so-called, indirect effect of aerosols, is recognized as one of the largest sources of uncertainty in climate prediction. The distribution of water vapor, precipitation, and ice cloud formation are influenced by the atmospheric ice formation, thereby modulating cloud albedo and thus climate. It is well known that different particle types possess different ice formation propensities with mineral dust being a superior ice nucleating particle (INP) compared to soot particles. Furthermore, some dust mineral types are more proficient INP than others, depending on temperature and relative humidity.In recent work, we have presented an improved dust aerosol module in the NASA GISS Earth System ModelE2 with prognostic mineral composition of the dust aerosols. Thus, there are regional variations in dust composition. We evaluated the predicted mineral fractions of dust aerosols by comparing them to measurements from a compilation of about 60 published literature references. Additionally, the capability of the model to reproduce the elemental composition of the simulated dusthas been tested at Izana Observatory at Tenerife, Canary Islands, which is located off-shore of Africa and where frequent dust events are observed. We have been able to show that the new approach delivers a robust improvement of the predicted mineral fractions and elemental composition of dust.In the current study, we use three-dimensional dust mineral fields and thermodynamic conditions, which are simulated using GISS ModelE, to calculate offline the INP concentrations derived using different ice nucleation parameterizations that are currently discussed. We evaluate the calculated INP concentrations from the different parameterizations by comparing them to INP concentrations from field measurements.

Characterisation of sub-micron particle number concentrations and formation events in the western Bushveld Igneous Complex, South Africa

Directory of Open Access Journals (Sweden)

A. Hirsikko

2012-05-01

Full Text Available South Africa holds significant mineral resources, with a substantial fraction of these reserves occurring and being processed in a large geological structure termed the Bushveld Igneous Complex (BIC. The area is also highly populated by informal, semi-formal and formal residential developments. However, knowledge of air quality and research related to the atmosphere is still very limited in the area. In order to investigate the characteristics and processes affecting sub-micron particle number concentrations and formation events, air ion and aerosol particle size distributions and number concentrations, together with meteorological parameters, trace gases and particulate matter (PM were measured for over two years at Marikana in the heart of the western BIC. The observations showed that trace gas (i.e. SO₂, NO_x, CO and black carbon concentrations were relatively high, but in general within the limits of local air quality standards. The area was characterised by very high condensation sink due to background aerosol particles, PM₁₀ and O₃ concentration. The results indicated that high amounts of Aitken and accumulation mode particles originated from domestic burning for heating and cooking in the morning and evening, while during daytime SO₂-based nucleation followed by the growth by condensation of vapours from industrial, residential and natural sources was the most probable source for large number concentrations of nucleation and Aitken mode particles. Nucleation event day frequency was extremely high, i.e. 86% of the analysed days, which to the knowledge of the authors is the highest frequency ever reported. The air mass back trajectory and wind direction analyses showed that the secondary particle formation was influenced both by local and regional pollution and vapour sources. Therefore, our observation of the annual cycle and magnitude of the particle formation and growth rates during

Measurement of thyroid volume, iodine concentration and total iodine content by CT and its clinical significance

International Nuclear Information System (INIS)

Nakaji, Shunsuke; Imanishi, Yoshimasa; Okamoto, Kyouko; Shinagawa, Toshihito

2007-01-01

Recently, Imanishi et al have developed new CT software for quantitative in vivo measurement of thyroid iodine. Using a CT system with the software, we measured volume, iodine concentration and total iodine content of thyroids in 63 controls and 435 patients with various diffuse thyroid diseases and thyroid nodules. In controls, all of them showed no difference between the sexes. Although the iodine concentration of the thyroid showed no difference among children, adults and seniles, the volume and total iodine content of the thyroid appeared smaller in children and seniles than in adults. In addition, although the volume and iodine concentration of the thyroid had two peaks in distribution, the total iodine content had almost normal distribution. Normal range of volume, iodine concentration and total iodine content in adults were 5.2-15.5 cm 3 , 0.28831-0.85919 mg/cm 3 and 2.35-11.69 mg, respectively. In thyroid nodule, there is no significant difference in volume, iodine concentration and total iodine content between benign and malignant nodules. All nodules with iodine concentration of less than 0.00007 mg/cm 3 were benign. No thyroid was higher in iodine concentration than the normal range although the thyroid was lower in 78.7% of patients with diffuse thyroid diseases. In all thyroids with increasing iodine concentration and total iodine content in medication course, thyroidal symptoms and signs were uncontrollable by the medication. In 43.8% of patients with long-period systemic diseases, the thyroid showed abnormality in any of the three. We concluded that quantitative in vivo measurement of thyroid iodine by CT could assist the diagnosis of thyroid diseases and decision of therapeutic methods. (author)

Spatial and indoor/outdoor gradients in urban concentrations of ultrafine particles and PM2.5 mass and chemical components

Science.gov (United States)

Zauli Sajani, Stefano; Ricciardelli, Isabella; Trentini, Arianna; Bacco, Dimitri; Maccone, Claudio; Castellazzi, Silvia; Lauriola, Paolo; Poluzzi, Vanes; Harrison, Roy M.

2015-02-01

In order to investigate relationships between outdoor air pollution and concentrations indoors, a novel design of experiment has been conducted at two sites, one heavily trafficked and the other residential. The novel design aspect involves the introduction of air directly to the centre of an unoccupied room by use of a fan and duct giving a controlled air exchange rate and allowing an evaluation of particle losses purely due to uptake on indoor surfaces without the losses during penetration of the building envelope which affect most measurement programmes. The rooms were unoccupied and free of indoor sources, and consequently reductions in particle concentration were due to deposition processes within the room alone. Measurements were made of indoor and outdoor concentrations of PM2.5, major chemical components and particle number size distributions. Despite the absence of penetration losses, indoor to outdoor ratios were very similar to those in other studies showing that deposition to indoor surfaces is likely to be the major loss process for indoor air. The results demonstrated a dramatic loss of nitrate in the indoor atmosphere as well as a selective loss of particles in the size range below 50 nm, in comparison to coarser particles. Depletion of indoor particles was greater during a period of cold weather with higher outdoor concentrations probably due to an enhancement of semi-volatile materials in the outdoor particulate matter. Indoor/outdoor ratios for PM2.5 were generally higher at the trafficked site than the residential site, but for particle number were generally lower, reflecting the different chemical composition and size distributions of particles at the two sites.

Concentration of aqueous extracts of defatted soy flour by ultrafiltration; Effect of suspended particles on the filtration flux

NARCIS (Netherlands)

Noordman, T.R.; Kooiker, K.; Bel, W.; Dekker, M.; Wesselingh, J.A.

2003-01-01

Suspended particles can have a positive effect on the flux and concentration curve of soy flour extracts during ultrafiltration. This is described by a simple empirical model. The suspended particles in this study were insoluble milled bean material (mean particle size 25 m). It is shown that it is

The Synergy between Meteorological Parameters and the Total ...

African Journals Online (AJOL)

because of its origin from mostly non-urban areas that ... particles in the air are readily removed by falling rain drop ..... Their physics and Physical ... Mass. Concentrations and Metals Speciation of PM2.5. PM10 and total suspended solids in ...

Emulsion Polymerization of Etyl Acrylate: The Effect of Surfactant, Initiator Concentration and PolymerizationTechnique on Particle Size Distribution

OpenAIRE

Nitri Arinda; Emil Budianto; Helmiyati

2009-01-01

Emulsion polymerization was conducted using ethyl acrylate monomer. Theeffect of sodium lauryl sulfate concentration, ammonium persulfate concentration, the various of polymerizationtechniques and feeding time to the conversion, particle size and its distribution were observed. The purpose of thisresearch is to obtain the optimum condition of ethyl acrylate homopolymer with particle size around 100 nm, to get theparticle size distribution monodisperse and to get solid content value of the exp...

Evaluation of indoor aerosol control devices and their effects on radon progeny concentrations

International Nuclear Information System (INIS)

Sextro, R.G.; Offermann, F.J.; Nazaroff, W.W.; Nero, A.V.; Revzan, K.L.; Yater, J.

1984-02-01

Eleven portable air cleaning devices have been evaluated for control of indoor concentrations of respirable particles, and their concomitant effects on radon progeny concentrations have been investigated. Of the devices we examined the electrostatic precipitators and extended surface filters had significant particle removal rates, while the particle removal rates for several small panel-filters, an ion-generator, and a pair of mixing fans were found to be negligible. The evaluation of radon progeny control produced similar results; the air cleaners which were effective in removing particles were also effective in reducing radon progeny concentrations. Furthermore, at the low particle concentrations, plateout of the unattached radon progeny was found to be a significant removal mechanism. The overall removal rates due to deposition of attached and unattached progeny have been estimated from these data, and the equilibrium factors for total and unattached progeny concentrations have been calculated as a function of particle concentration. 7 references, 2 figures

Evaluation of indoor aerosol control devices and their effects on radon progeny concentrations

International Nuclear Information System (INIS)

Sextro, R.G.; Offerman, F.J.; Nazaroff, W.W.; Nero, A.V.; Revzan, K.; Yater, J.

1984-01-01

Eleven portable air cleaing devices have been evaluated for control of indoor concentrations of respirable particles, and their concomitant effects on radon progeny concentrations have been investigated. Of the devices we examined the electrostatic precipitators and extended surface filters had significant particle removal rates, while the particle removal rates for several small panel-filters, an ion-generator, and a pair of mixing fans were found to be negligible. The evaluation of radon progeny control produced similar results; the air cleaners which were effective in removing particles were also effective in reducing radon progeny concentrations. Futhermore, at the low particle concentrations, plateout of the unattached radon progeny was found to be a significant removal mechanism. The overall removal rates due to deposition of attached and unattached progeny have been estimated from these data, and the equilibrium factors for total and unattached progeny concentrations have been calculated as a function of particle concentration. (Author)

Seasonal variations of total 234Th and dissolved 238U concentration activities in surface water of Bransfield Strait, Antarctica, from March to October 2011

International Nuclear Information System (INIS)

Lapa, Flavia V.; Oliveira, Joselene de; Costa, Alice M.R.; Braga, Elisabete S.

2013-01-01

In this study the naturally occurring radionuclides 234 Th and 238 U were used to investigate the magnitude of upper ocean particulate organic carbon export in Bransfield Strait, Southern Ocean. This region is the largest oceanic high-nitrate low-chlorophyll (HNLC) area in the world and is known to contribute to regulate of the atmospheric CO 2 via the biological pump. Due to its different geochemical behavior in seawater, the resulting U/Th disequilibria can be easily used to constrain the transport rates of particles and reaction processes between solution and particulate phases. Sampling occurred during the summer (March and November) 2011. Total 234 Th activities in surface seawater samples ranged from 1.3 to 3.7 dpm L -1 (station EB 011) during March/11 campaign, while in October/11 total 234 Th activity concentrations varied from 1.4 to 2.9 dpm L -1 . Highest total 234 Th activities were found late in the austral summer season. Activity concentrations of dissolved 238 U in surface seawater varied from 2.1 to 2.4 dpm L -1 . Taking into account all sampling stations established in March and October/11 the relative variability of total 234 Th distribution was 22%. (author)

Zone of influence for particle number concentrations at signalised traffic intersections

Science.gov (United States)

Goel, Anju; Kumar, Prashant

2015-12-01

Estimation of zone of influences (ZoI) at signalised traffic intersections (TI) is important to accurately model particle number concentrations (PNCs) and their exposure to public at emission hotspot locations. However, estimates of ZoI for PNCs at different types of TIs are barely known. We carried out mobile measurements inside the car cabin with windows fully open for size-resolved PNCs in the 5-560 nm range on a 6 km long busy round route that had 10 TIs. These included four-way TIs without built-up area (TI4w-nb), four-way TIs with built-up area (TI4w-wb), three-way TIs without built-up area (TI3w-nb) and three-way TIs with built-up area (TI3w-wb). Mobile measurements were made with a fast response differential mobility spectrometer (DMS50). Driving speed and position of the car were recorded every second using a global positioning system (GPS). Positive matrix factorisation (PMF) modelling was applied on the data to quantify the contribution of PNCs released during deceleration, creep-idling, acceleration and cruising to total PNCs at the TIs. The objectives were to address the following questions: (i) how does ZoI vary at different types of TIs in stop- and go-driving conditions?, (ii) what is the effect of different driving conditions on ZoI of a TI?, (iii) how realistically can the PNC profiles be generalised within a ZoI of a TI?, and (iv) what is the share of emissions during different driving conditions towards the total PNCs at a TI? Average length of ZoI in longitudinal direction and along the road was found to be the highest (148 m; 89 to -59 m from the centre of a TI) at a TI3w-wb, followed by TI4w-nb (129 m; 79 to -42 m), TI3w-nb (86 m; 71 to -15 m) and TI4w-wb (79 m; 46 to -33 m) in stop- and go-driving conditions. During multiple stopping driving conditions when a vehicle stops at a TI more than once in a signal cycle due to oversaturation of vehicles, average length of ZoI increased by 55, 22 and 21% at TI4w-nb, TI3w-nb and TI3w-wb, respectively

Enhancing effect of marine oligotrophy on environmental concentrations of particle-reactive trace elements

International Nuclear Information System (INIS)

Jeffree, R.A.; Szymczak, R.

2000-01-01

A biogeochemical model has been previously developed that explains the inverse and nonlinear relationship between Po-210 concentration in zooplankton and their biomass, under oligotrophic conditions in French Polynesia. In this study the model structure was reviewed to determine a set of biogeochemical behaviors of Po-210, proposed to be critical to its environmental enhancement under oligotrophy: this set was then used to identify 25 other elements with comparable behaviors to Po-210. Field investigation in the Timor Sea showed that four of these a priori identified elements, viz. Cd, Co, Pb, and Mn as well as Cr and Ni, showed elevated water concentrations with reduced particle removal rates in the euphotic zone, results that are consistent with those previously obtained for Po-210 and the proposed explanatory model. These findings point to the enhanced susceptibility to contamination with particle-reactive elements of oligotrophic marine systems, whose degree and geographic extent may be enhanced by projected increases in sea surface temperatures from global warming

Exposure assessment of workplace manufacturing titanium dioxide particles

International Nuclear Information System (INIS)

Xu, Huadong; Zhao, Lin; Chen, Zhangjian; Zhou, Jingwen; Tang, Shichuan; Kong, Fanling; Li, Xinwei; Yan, Ling; Zhang, Ji; Jia, Guang

2016-01-01

With the widespread use of titanium dioxide (TiO 2 ) human exposure is inevitable, but the exposure data on TiO 2 are still limited. This study adopted off-line filter-based sampling combined with real-time activity-based monitoring to measure the concentrations in a workplace manufacturing TiO 2 (primary diameter: 194 ± 108 nm). Mass concentrations (MCs) of aerosol particles in the packaging workshop (total dust: 3.17 mg/m 3 , nano dust: 1.22 mg/m 3 ) were much higher than those in the milling workshop (total dust: 0.79 mg/m 3 , nano dust: 0.31 mg/m 3 ) and executive office (total dust: 0.44 mg/m 3 , nano dust: 0.19 mg/m 3 ). However, the MCs of TiO 2 were at a relatively low level in the packaging workshop (total TiO 2 : 46.4 μg/m 3 , nano TiO 2 : 16.7 μg/m 3 ) and milling workshop (total TiO 2 : 39.4 μg/m 3 , nano TiO 2 : 19.4 μg/m 3 ) by ICP-MS. The number concentration (NC), surface area concentration (SAC) of aerosol particles potentially deposited in alveolar (SAC A ), and tracheobronchial (SAC TB ) regions of lungs in the packaging workshop were (1.04 ± 0.89) × 10 5 particles/cm 3 , 414.49 ± 395.07, and 86.01 ± 83.18 μm 2 /cm 3 , respectively, which were all significantly higher than those of the milling workshop [(0.12 ± 0.40) × 10 5 particles/cm 3 , 75.38 ± 45.23, and 17.60 ± 9.22 μm 2 /cm 3 , respectively] as well as executive office and outdoor background (p < 0.05). Activity-related characteristics were found in both workshops, and the time-variant characteristics showed very similar trends for 3 days in the packaging workshop. Our study provides important data of TiO 2 particles exposure in the workplace.

A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles

Energy Technology Data Exchange (ETDEWEB)

Sarker, M. R. I., E-mail: islamrabiul@yahoo.com; Saha, Manabendra, E-mail: manabendra.saha@adelaide.edu.au, E-mail: manab04me@gmail.com; Beg, R. A. [Department of Mechanical Engineering, Rajshahi University of Engineering and Technology, Rajshahi-6204 (Bangladesh)

2016-07-12

A recirculating flow solar particle cavity absorber (receiver) is modeled to investigate the flow behavior and heat transfer characteristics of a novel developing concept. It features a continuous recirculating flow of non-reacting metallic particles (black silicon carbide) with air which are used as a thermal enhancement medium. The aim of the present study is to numerically investigate the thermal behavior and flow characteristics of the proposed concept. The proposed solar particle receiver is modeled using two phase discrete particle model (DPM), RNG k-flow model and discrete ordinate (DO) radiation model. Numerical analysis is carried out considering a solar receiver with only air and the mixture of non-reacting particles and air as a heat transfer as well as heat carrying medium. The parametric investigation is conducted considering the incident solar flux on the receiver aperture and changing air flow rate and recirculation rate inside the receiver. A stand-alone feature of the recirculating flow solar particle receiver concept is that the particles are directly exposed to concentrated solar radiation monotonously through recirculating flow inside the receiver and results in efficient irradiation absorption and convective heat transfer to air that help to achieve high temperature air and consequently increase in thermal efficiency. This paper presents, results from the developed concept and highlights its flow behavior and potential to enhance the heat transfer from metallic particles to air by maximizing heat carrying capacity of the heat transfer medium. The imposed milestones for the present system will be helpful to understand the radiation absorption mechanism of the particles in a recirculating flow based receiver, the thermal transport between the particles, the air and the cavity, and the fluid dynamics of the air and particle in the cavity.

Monitoring total endotoxin and (1 --> 3)-beta-D-glucan at the air exhaust of concentrated animal feeding operations.

Science.gov (United States)

Yang, Xufei; Wang, Xinlei; Zhang, Yuanhui; Lee, Jongmin; Su, Jingwei; Gates, Richard S

2013-10-01

Mitigation of bioaerosol emissions from concentrated animal feeding operations (CAFOs) demands knowledge of bioaerosol concentrations feeding into an end-of-pipe air treatment process. The aim of this preliminary study was to measure total endotoxin and (1 --> 3)-beta-glucan concentrations at the air exhaust of 18 commercial CAFOs and to examine their variability with animal operation type (swine farrowing, swine gestation, swine weaning, swine finishing, manure belt laying hen, and tom turkey) and season (cold, mild, and hot). The measured airborne concentrations of total endotoxin ranged from 98 to 23,157 endotoxin units (EU)/m3, and the airborne concentrations of total (1 --> 3)-beta-D-glucan ranged from 2.4 to 537.9 ng/m3. Animal operation type in this study had a significant effect on airborne concentrations of total endotoxin and (1 --> 3)-beta-D-glucan but no significant effect on their concentrations in total suspended particulate (TSP). Both endotoxin and (1 --> 3)-beta-D-glucan attained their highest airborne concentrations in visited tom turkey buildings. Comparatively, season had no significant effect on airborne concentrations of total endotoxin or (1 --> 3)-beta-D-glucan. Endotoxin and (1 --> 3)-beta-glucan concentrations in TSP dust appeared to increase as the weather became warmer, and this seasonal effect was significant in swine buildings. Elevated indoor temperatures in the hot season were considered to facilitate the growth and propagation of bacteria and fungi, thus leading to higher biocomponent concentrations in TSP.

Reduction of indoor particles concentration using re-circulating filtration units in Danish dwellings

DEFF Research Database (Denmark)

Spilak, Michal; Frederiksen, Marie; Karottki, Gabriela D.

2012-01-01

air was recirculated through the unit during two weeks in a randomized and double blinded design. The measurements included concentration of PM2.5 and ultrafine particles (UPC), carbon dioxide, temperature and relative humidity, ventilation, air flow through the unit, allergen and fungal levels....... Additional information was collected through questionnaires. Several medical tests were made, however the results are not included in this paper. Preliminary results showed significant decrease in PM2.5 concentration during the filtered period compared to placebo period. Likewise was UPC significantly lower...

Effects of fumaric acid supplementation on methane production and rumen fermentation in goats fed diets varying in forage and concentrate particle size.

Science.gov (United States)

Li, Zongjun; Liu, Nannan; Cao, Yangchun; Jin, Chunjia; Li, Fei; Cai, Chuanjiang; Yao, Junhu

2018-01-01

In rumen fermentation, fumaric acid (FA) could competitively utilize hydrogen with methanogenesis to enhance propionate production and suppress methane emission, but both effects were diet-dependent. This study aimed to explore the effects of FA supplementation on methanogenesis and rumen fermentation in goats fed diets varying in forage and concentrate particle size. Four rumen-cannulated goats were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments: low or high ratio of forage particle size: concentrate particle size (Fps:Cps), without or with FA supplementation (24 g/d). Fps:Cps was higher in the diet with chopped alfalfa hay plus ground corn than in that with ground alfalfa hay plus crushed corn. Both increasing dietary Fps:Cps and FA supplementation shifted ruminal volatile fatty acid (VFA) patterns toward more propionate and less acetate in goats. An interaction between dietary Fps:Cps and FA supplementation was observed for the ratio of acetate to propionate (A:P), which was more predominant when FA was supplemented in the low-Fps:Cps diet. Methane production was reduced by FA, and the reduction was larger in the low-Fps:Cps diet (31.72%) than in the high-Fps:Cps diet (17.91%). Fumaric acid decreased ruminal total VFA concentration and increased ruminal pH. No difference was found in ruminal DM degradation of concentrate or alfalfa hay by dietary Fps:Cps or FA. Goats presented a lower ruminal methanogen abundance with FA supplementation and a higher B. fibrisolvens abundance with high dietary Fps:Cps. Adjusting dietary Fps:Cps is an alternative dietary model for studying diet-dependent effects without changing dietary chemical composition. Fumaric acid supplementation in the low-Fps:Cps diet showed greater responses in methane mitigation and propionate increase.

Size evolution of ultrafine particles: Differential signatures of normal and episodic events

International Nuclear Information System (INIS)

Joshi, Manish; Khan, Arshad; Anand, S.; Sapra, B.K.

2016-01-01

The effect of fireworks on the aerosol number characteristics of atmosphere was studied for an urban mega city. Measurements were made at 50 m height to assess the local changes around the festival days. Apart from the increase in total number concentration and characteristic accumulation mode, short-term increase of ultrafine particle concentration was noted. Total number concentration varies an order of magnitude during the measurement period in which peak occurs at a frequency of approximately one per day. On integral scale, it seems not possible to distinguish an episodic (e.g. firework bursting induced aerosol emission) and a normal (ambient atmospheric changes) event. However these events could be differentiated on the basis of size evolution analysis around number concentration peaks. The results are discussed relative to past studies and inferences are drawn towards aerosol signatures of firework bursting. The short-term burst in ultrafine particle concentration can pose an inhalation hazard. - Highlights: • Effect of firework emissions on atmospheric aerosol characteristics was studied. • Significant increase in ultrafine particle concentration was observed during firework bursting. • Size distribution evolution analysis of number concentration peaks has been performed. • Differential signatures of normal and episodic event were noted. - Notable increase in ultrafine particle concentration during firework bursting was seen. Normal and episodic event could be differentiated on the basis of size evolution analysis.

Effect of the particle size of maize, rice, and sorghum in extruded diets for dogs on starch gelatinization, digestibility, and the fecal concentration of fermentation products.

Science.gov (United States)

Bazolli, R S; Vasconcellos, R S; de-Oliveira, L D; Sá, F C; Pereira, G T; Carciofi, A C

2015-06-01

The influence of rice, maize, and sorghum raw material particle size in extruded dry dog food on the digestibility of nutrients and energy and the fecal concentration of fermentation products was investigated. Three diets with similar nutrient compositions were formulated, each with 1 starch source. Before incorporation into diets, the cereals were ground into 3 different particle sizes (approximately 300, 450, and 600 µm); therefore, a total of 9 diets were in a 3 × 3 factorial arrangement (3 cereals and 3 particle sizes). Fifty-four beagle dogs (12.0 ± 0.1 kg BW) were randomly assigned to the diets, with 6 dogs per diet. The digestibility was measured with the chromium oxide method. The data were evaluated with ANOVA considering the carbohydrate source, grinding effect, and interactions. The means were compared with the Tukey test and polynomial contrasts (P 0.05); only GE digestibility was reduced at the largest MGD (P production of feces with less lactate (P dogs fed maize and sorghum foods, an increase in propionate and butyrate concentrations were observed as MGD increased (P dogs fed different particle sizes of the cereal starches in the extruded diets, the digestibility and fecal characteristics were affected, and this effect was ingredient dependent.

Toxic assessment of urban atmospheric particle-bound PAHs: Relevance of composition and particle size in Barcelona (Spain)

International Nuclear Information System (INIS)

Mesquita, Sofia Raquel; Drooge, Barend L. van; Reche, Cristina; Guimarães, Laura; Grimalt, Joan O.; Barata, Carlos; Piña, Benjamin

2014-01-01

Zebrafish embryotoxicity and dioxin-like activity levels were tested for particulate air samples from an urban background site in Barcelona (Spain). Samples were collected during 14 months, and maximal values for both biological activities corresponded to samples collected during late autumn months, correlating with elevated PAH levels. Vehicle and combustion emissions appeared as the potentially most toxic sources, whereas total PM mass and mineral content appeared to be poor predictors of the biological activity of the samples. Samples simultaneously collected at different particle size cut-offs (10, 2.5, and 1 μm) did not differ significantly in dioxin-like PAH levels and biological activity, indicating that the sub-micron particle fraction (PM 1 ) concentrated essentially all observed toxicity. Our results support the need for a tighter control on sub-micron particle emissions and show that total PM mass and, particularly, PM 10 , may not fully characterize the toxic potential of air samples. Highlights: • Dioxin-like activity was found in all air particle samples collected in Barcelona. • 50% of the samples showed different levels of fish embryotoxicity. • Toxic effects associated to PAHs and linked to vehicle and combustion emissions. • The toxicity was not correlated to PM mass or mineral content. • The sub-micron particle fraction PM 1 concentrated essentially all observed toxicity. -- In vivo toxic effects associated to sub-micron urban air particles from combustion and vehicle emissions

Long-term cloud condensation nuclei number concentration, particle number size distribution and chemical composition measurements at regionally representative observatories

Directory of Open Access Journals (Sweden)

J. Schmale

2018-02-01

Full Text Available Aerosol–cloud interactions (ACI constitute the single largest uncertainty in anthropogenic radiative forcing. To reduce the uncertainties and gain more confidence in the simulation of ACI, models need to be evaluated against observations, in particular against measurements of cloud condensation nuclei (CCN. Here we present a data set – ready to be used for model validation – of long-term observations of CCN number concentrations, particle number size distributions and chemical composition from 12 sites on 3 continents. Studied environments include coastal background, rural background, alpine sites, remote forests and an urban surrounding. Expectedly, CCN characteristics are highly variable across site categories. However, they also vary within them, most strongly in the coastal background group, where CCN number concentrations can vary by up to a factor of 30 within one season. In terms of particle activation behaviour, most continental stations exhibit very similar activation ratios (relative to particles  > 20 nm across the range of 0.1 to 1.0 % supersaturation. At the coastal sites the transition from particles being CCN inactive to becoming CCN active occurs over a wider range of the supersaturation spectrum. Several stations show strong seasonal cycles of CCN number concentrations and particle number size distributions, e.g. at Barrow (Arctic haze in spring, at the alpine stations (stronger influence of polluted boundary layer air masses in summer, the rain forest (wet and dry season or Finokalia (wildfire influence in autumn. The rural background and urban sites exhibit relatively little variability throughout the year, while short-term variability can be high especially at the urban site. The average hygroscopicity parameter, κ, calculated from the chemical composition of submicron particles was highest at the coastal site of Mace Head (0.6 and lowest at the rain forest station ATTO (0.2–0.3. We performed closure

Improvement in mechanical properties of high concentration particle doped thermoset composites

International Nuclear Information System (INIS)

Ahmed, N.

2009-01-01

The paper relates to high concentration particle doped composites based on thermosetting polymer systems in which the sequential addition of particles of certain size distribution is followed by curing and casting of the slurry to form a thermoset composite. Conventionally, at a threshold of beyond 90% of particles by weight of the polymer using triglyceride, the mechanical properties of the composite exhibit a sharp decline. The present research mitigates this behavior by incorporating a unique combination of cross-linking agents in the base polymer to impart exceptional mechanical properties to the composite. More specifically, the base polymer consists of butadiene, with triglyceride as cross-linking agent together with hydroxy-alkane as the chain extension precursors, when tune to the appropriate level of hard segment ratio in the polymer. An added advantage according to the present work resides in the analytical nature of butadiene pre-polymer as opposed to natural product; traditional composites based on natural sources are hampered by their inconsistent chemical composition and poor shelf life in the fabricated composite. The thermoset composite according the present research exhibits superior tensile strength (200-300 psi) properties using particle loading as high as 92% by weight of the fabricated composite as measured on a Tinius Olsen machine. Dynamic Mechanical Testing reveals interesting combination of storage and loss moduli in the fabricated specimens as a function of optimizing the thermal response of the viscoelastic composite to imposed vibration loading. (author)

Particle size distribution and property of bacteria attached to carbon fines in drinking water treatment

Directory of Open Access Journals (Sweden)

Wang Leilei

2008-06-01

Full Text Available The quantitative change and size distribution of particles in the effluents from a sand filter and a granular activated carbon (GAC filter in a drinking water treatment plant were investigated. The average total concentration of particles in the sand filter effluent during a filter cycle was 148 particles/mL, 27 of which were larger than 2 µm in size. The concentration in the GAC effluent (561 particles/mL was significantly greater than that in the sand filter effluent. The concentration of particles larger than 2 µm in the GAC filter effluent reached 201 particles/mL, with the amount of particles with sizes between 2 µm and 15 µm increasing. The most probable number (MPN of carbon fines reached 43 unit/L after six hours and fines between 0.45 µm and 8.0 µm accounted for more than 50%. The total concentration of outflowing bacteria in the GAC filter effluent, 350 CFU (colony-forming units/mL, was greater than that in the sand filter effluent, 210 CFU/mL. The desorbed bacteria concentration reached an average of 310 CFU/mg fines. The disinfection efficiency of desorbed bacteria was lower than 40% with 1.5 mg/L of chlorine. The disinfection effect showed that the inactivation rate with 2.0 mg/L of chloramine (90% was higher than that with chlorine (70%. Experimental results indicated that the high particle concentration in raw water and sedimentation effluent led to high levels of outflowing particles in the sand filter effluent. The activated carbon fines in the effluent accounted for a small proportion of the total particle amount, but the existing bacteria attached to carbon fines may influence the drinking water safety. The disinfection efficiency of desorbed bacteria was lower than that of free bacteria with chlorine, and the disinfection effect on bacteria attached to carbon fines with chloramine was better than that with only chlorine.

Characterisation of particle mass and number concentration on the east coast of the Malaysian Peninsula during the northeast monsoon

Science.gov (United States)

Dominick, Doreena; Latif, Mohd Talib; Juneng, Liew; Khan, Md Firoz; Amil, Norhaniza; Mead, Mohammed Iqbal; Nadzir, Mohd Shahrul Mohd; Moi, Phang Siew; Samah, Azizan Abu; Ashfold, Matthew J.; Sturges, William T.; Harris, Neil R. P.; Robinson, Andrew D.; Pyle, John A.

2015-09-01

Particle mass concentrations (PM10, PM2.5 and PM1) and particle number concentration ((PNC); 0.27 μm ≤ Dp ≤ 34.00 μm) were measured in the tropical coastal environment of Bachok, Kelantan on the Malaysian Peninsula bordering the southern edge of the South China Sea. Statistical methods were applied on a three-month hourly data set (9th January to 24th March 2014) to study the influence of north-easterly winds on the patterns of particle mass and PNC size distributions. The 24-h concentrations of particle mass obtained in this study were below the standard values detailed by the Recommended Malaysian Air Quality Guideline (RMAQG), United States Environmental Protection Agency (US EPA) and European Union (EU) except for PM2.5, which recorded a 24-h average of 30 ± 18 μg m-3 and exceeded the World Health Organisation (WHO) threshold value (25 μg m-3). Principal component analysis (PCA) revealed that PNC with smaller diameter sizes (0.27-4.50 μm) showed a stronger influence, accounting for 57.6% of the variability in PNC data set. Concentrations of both particle mass and PNC increased steadily in the morning with a distinct peak observed at around 8.00 h, related to a combination of dispersion of accumulated particles overnight and local traffic. In addition to local anthropogenic, agricultural burning and forest fire activities, long-range transport also affects the study area. Hotspot and backward wind trajectory observations illustrated that the biomass burning episode (around February-March) significantly influenced PNC. Meteorological parameters influenced smaller size particles (i.e. PM1 and Dp (0.27-0.43 μm)) the most.

Temperature dependence of the particle/gas partition coefficient: An application to predict indoor gas-phase concentrations of semi-volatile organic compounds

Energy Technology Data Exchange (ETDEWEB)

Wei, Wenjuan, E-mail: Wenjuan.Wei@cstb.fr [University of Paris-Est, Scientific and Technical Center for Building (CSTB), Health and Comfort Department, French Indoor Air Quality Observatory (OQAI), 84 Avenue Jean Jaurès, Champs sur Marne, 77447 Marne la Vallée Cedex 2 (France); Mandin, Corinne [University of Paris-Est, Scientific and Technical Center for Building (CSTB), Health and Comfort Department, French Indoor Air Quality Observatory (OQAI), 84 Avenue Jean Jaurès, Champs sur Marne, 77447 Marne la Vallée Cedex 2 (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); LERES-Environment and Health Research Laboratory (Irset and EHESP Technologic Platform), Rennes (France); Blanchard, Olivier [EHESP-School of Public Health, Sorbonne Paris Cité, Rennes (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); Mercier, Fabien [EHESP-School of Public Health, Sorbonne Paris Cité, Rennes (France); LERES-Environment and Health Research Laboratory (Irset and EHESP Technologic Platform), Rennes (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); Pelletier, Maud [EHESP-School of Public Health, Sorbonne Paris Cité, Rennes (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); Le Bot, Barbara [EHESP-School of Public Health, Sorbonne Paris Cité, Rennes (France); LERES-Environment and Health Research Laboratory (Irset and EHESP Technologic Platform), Rennes (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); and others

2016-09-01

The indoor gas-phase concentrations of semi-volatile organic compounds (SVOCs) can be predicted from their respective concentrations in airborne particles by applying the particle/gas partitioning equilibrium. The temperature used for partitioning is often set to 25 °C. However, indoor temperatures frequently differ from this reference value. This assumption may result in errors in the predicted equilibrium gas-phase SVOC concentrations. To improve the prediction model, the temperature dependence of the particle/gas partition coefficient must be addressed. In this paper, a theoretical relationship between the particle/gas partition coefficient and temperature was developed based on the SVOC absorptive mechanism. The SVOC particle/gas partition coefficients predicted by employing the derived theoretical relationship agree well with the experimental data retrieved from the literature (R > 0.93). The influence of temperature on the equilibrium gas-phase SVOC concentration was quantified by a dimensionless analysis of the derived relationship between the SVOC particle/gas partition coefficient and temperature. The predicted equilibrium gas-phase SVOC concentration decreased by between 31% and 53% when the temperature was lowered by 6 °C, while it increased by up to 750% when the indoor temperature increased from 15 °C to 30 °C. - Highlights: • A theoretical relationship between K{sub p} and temperature was developed. • The relationship was based on the SVOC absorptive mechanism. • The temperature impact was quantified by a dimensionless analysis.

Effect on blood lead of airborne lead particles characterized by size.

Science.gov (United States)

Park, Dong-Uk; Paik, Nam-Won

2002-03-01

Worker exposure to airborne lead particles was evaluated for a total of 117 workers in 12 work-places of four different industrial types in Korea. The particle sizes were measured using 8-stage cascade impactors worn by the workers. Mass median aerodynamic diameters (MMAD) were determined by type of industry and percentage of lead particles as a fraction of airborne lead (PbA) concentration was determined by particle size. Blood lead (PbB) levels of workers who matched airborne lead samples were also examined. A Scheffé's pairwise comparison test showed that MMAD and the fractions of each of respirable particles and lead particles lead particles lead particles (r = 0.82) than that between concentrations of small particles and PbA (r = 0.61). A simple linear regression indicated that PbB correlated better with respirable lead concentration (r2 = 0.35, P = 0.0001) than with PbA concentration and had a higher slope coefficient. Controlling for respirable lead concentration reduced the partial correlation coefficient between PbA concentration and PbB level from 0.56 to 0.20 (P = 0.053). The results indicate that the contribution of respirable lead particles to lead absorption would be greater than that of PbA. This study concludes that the measurement of PbA only may not properly reflect a worker's exposure to lead particles with diverse characteristics. For the evaluation of a worker's exposure to various types of lead particles, it is recommended that respirable lead particles as well as PbA be measured.

Effects of total gastrectomy on plasma silicon and amino acid concentrations in men.

Science.gov (United States)

Tatara, Marcin R; Krupski, Witold; Szpetnar, Maria; Dąbrowski, Andrzej; Bury, Paweł; Szabelska, Anna; Charuta, Anna; Boguszewska-Czubara, Anna; Maciejewski, Ryszard; Wallner, Grzegorz

2015-12-01

The aim of the study was to determine one-year effects of total gastrectomy on plasma silicon and free amino acid concentrations in patients and evaluate changes of volumetric bone mineral density (vBMD) in lumbar spine. Eight patients were enrolled to the control (CTR) group. Six patients subjected to total gastrectomy (GX group) were included to the experimental group. vBMD in trabecular and cortical bone was measured in lumbar vertebrae at baseline (before surgery) and one year later using quantitative computed tomography. Plasma concentrations of silicon and free amino acids were determined at baseline and one year later using photometric method and ion-exchange chromatography. Body weights within CTR and GX groups were not different after one-year follow-up when compared to the baseline values (P > 0.05). An average annual decrease of vBMD in the trabecular bone in the gastrectomized patients reached 15.0% in lumbar spine and was significantly different in comparison to the percentage changes observed in CTR group (P = 0.02). One-year percentage change of vBMD in the cortical bone in L1 and L2 has shown significantly decreased values by 10.5 and 9.1% in the GX group when compared to the percentage change observed in the controls (P silicon was significantly lowered by 26.7% one year after the total gastrectomy when compared to the baseline value (P = 0.009). Total gastrectomy in patients has induced severe osteoporotic changes in lumbar spine within one-year period. The observed osteoporotic changes were associated with decreased plasma concentration of silicon indicating importance of exocrine and endocrine functions of stomach for silicon homeostasis maintenance. Gastrectomy-induced bone loss was not related to decreased amino acid concentration in plasma obtained from overnight fasted patients. © 2015 by the Society for Experimental Biology and Medicine.

Simultaneous measurement of local particle movement, solids concentrations and bubble properties in fluidized bed reactors using a novel fiber optical technique

Energy Technology Data Exchange (ETDEWEB)

Tayebi, Davoud

1999-12-31

This thesis develops a new method for simultaneous measurements of local flow properties in highly concentrated multiphase flow systems such as gas-solid fluidized bed reactors. The method is based on fiber optical technique and tracer particles. A particle present in the measuring volume in front of the probe is marked with a fluorescent dye. A light source illuminates the particles and the detecting fibres receive reflected light from uncoated particles and fluorescent light from the tracer particle. Using optical filters, the fluorescent light can be distinguished and together with a small fraction of background light from uncoated particles can be used for determination of local flow properties. Using this method, one can simultaneously measure the local movement of a single tracer particle, local bubble properties and the local solids volume fractions in different positions in the bed. The method is independent of the physical properties of the tracer particles. It is also independent of the local solids concentrations in the range of 0 to 60 vol.-%, but is mainly designed for highly concentrated flow systems. A computer programme that uses good signals from at least three sensors simultaneously to calculate the tracer particle velocity in two dimensions have been developed. It also calculates the bubble properties and local solids volume fractions from the same time series. 251 refs., 150 figs., 5 tabs.

Simultaneous measurement of local particle movement, solids concentrations and bubble properties in fluidized bed reactors using a novel fiber optical technique

Energy Technology Data Exchange (ETDEWEB)

Tayebi, Davoud

1998-12-31

This thesis develops a new method for simultaneous measurements of local flow properties in highly concentrated multiphase flow systems such as gas-solid fluidized bed reactors. The method is based on fiber optical technique and tracer particles. A particle present in the measuring volume in front of the probe is marked with a fluorescent dye. A light source illuminates the particles and the detecting fibres receive reflected light from uncoated particles and fluorescent light from the tracer particle. Using optical filters, the fluorescent light can be distinguished and together with a small fraction of background light from uncoated particles can be used for determination of local flow properties. Using this method, one can simultaneously measure the local movement of a single tracer particle, local bubble properties and the local solids volume fractions in different positions in the bed. The method is independent of the physical properties of the tracer particles. It is also independent of the local solids concentrations in the range of 0 to 60 vol.-%, but is mainly designed for highly concentrated flow systems. A computer programme that uses good signals from at least three sensors simultaneously to calculate the tracer particle velocity in two dimensions have been developed. It also calculates the bubble properties and local solids volume fractions from the same time series. 251 refs., 150 figs., 5 tabs.

A novel method for determination of particle size distribution in-process

Science.gov (United States)

Salaoru, Tiberiu A.; Li, Mingzhong; Wilkinson, Derek

2009-07-01

The pharmaceutical and fine chemicals industries are strongly concerned with the manufacture of high value-added speciality products, often in solid form. On-line measurement of solid particle size is vital for reliable control of product properties. The established techniques, such as laser diffraction or spectral extinction, require dilution of the process suspension when measuring from typical manufacturing streams because of their high concentration. Dilution to facilitate measurement can result in changes of both size and form of particles, especially during production processes such as crystallisation. In spectral extinction, the degree of light scattering and absorption by a suspension is measured. However, for concentrated suspensions the interpretation of light extinction measurements is difficult because of multiple scattering and inter-particle interaction effects and at higher concentrations extinction is essentially total so the technique can no longer be applied. At the same time, scattering by a dispersion also causes a change of phase which affects the real component of the suspension's effective refractive index which is a function of particle size and particle and dispersant refractive indices. In this work, a novel prototype instrument has been developed to measure particle size distribution in concentrated suspensions in-process by measuring suspension refractive index at incidence angles near the onset of total internal reflection. Using this technique, the light beam does not pass through the suspension being measured so suspension turbidity does not impair the measurement.

Concentration of circulating miRNA-containing particles in serum enhances miRNA detection and reflects CRC tissue-related deregulations.

Science.gov (United States)

ElSharawy, Abdou; Röder, Christian; Becker, Thomas; Habermann, Jens K; Schreiber, Stefan; Rosenstiel, Philip; Kalthoff, Holger

2016-11-15

The emerging potential of miRNAs as biomarkers for cancer detection demands parallel evaluation of strategies for reliable identification of disease-related signatures from easily accessible and pertinent body compartments. Here, we addressed whether efficient concentration of circulating miRNA-carrying particles is a rationale for miRNA biomarker discovery. We systematically compared miRNA signatures in 93 RNA preparations from three serum entities (whole serum, particle-concentrated, and particle-depleted fractions) and corresponding tissue samples from patients with colorectal cancer (CRC) as a model disease. Significant differences between whole sera and particle-concentrated serum fractions of CRC patients emerged for 45 of 742 tested miRNAs. Twenty-eight of these 45 miRNAs were differentially expressed between particle-concentrated serum fractions of metastatic CRC- and healthy individuals. Over half of these candidates (15 of 28) showed deregulations only in concentrated serum fractions, but not in whole sera, compared to the respective controls.Our results also provided evidence of a consistent downregulation of miR-486 and miR-92a, and further showed a possible "strand-specific" deregulation of extracellular miRNAs in CRC. More importantly, most of the identified miRNAs in the enriched sera reflected the patterns of the corresponding tumor tissues and showed links to cancer-related inflammation. Further investigation of seven serum pools revealed a subset of potential extracellular miRNA candidates to be implicated in both neoplastic and inflammatory bowel disease.Our findings demonstrate that enrichment and sensitive detection of miRNA carriers is a promising approach to detect CRC-related pathological changes in liquid biopsies, and has potential for clinical diagnostics.

Phenology of a Vegetation Barrier and Resulting Impacts on Near-Highway Particle Number and Black Carbon Concentrations on a School Campus

Directory of Open Access Journals (Sweden)

Christina H. Fuller

2017-02-01

Full Text Available Traffic-related air pollution is a persistent concern especially in urban areas where populations live in close proximity to roadways. Innovative solutions are needed to minimize human exposure and the installation of vegetative barriers shows potential as a method to reduce near-road concentrations. This study investigates the impact of an existing stand of deciduous and evergreen trees on near-road total particle number (PNC and black carbon (BC concentrations across three seasons. Measurements were taken during spring, fall and winter on the campus of a middle school in the Atlanta (GA, USA area at distances of 10 m and 50 m from a major interstate highway. We identified consistent decreases in BC concentrations, but not for PNC, with increased distance from the highway. In multivariable models, hour of day, downwind conditions, distance to highway, temperature and relative humidity significantly predicted pollutant concentrations. The magnitude of effect of these variables differed by season, however, we were not able to show a definitive impact of the vegetative barrier on near-road concentrations. More detailed studies are necessary to further examine the specific configurations and scenarios that may produce pollutant and exposure reductions.

Effect of particle size distribution and concentration on flow behavior of dense slurries

Czech Academy of Sciences Publication Activity Database

Vlasák, Pavel; Chára, Zdeněk

2011-01-01

Roč. 29, č. 1 (2011), s. 53-65 ISSN 0272-6351 R&D Projects: GA ČR(CZ) GAP105/10/1574 Institutional research plan: CEZ:AV0Z20600510 Keywords : concentration effect * dense complex slurry * experimental investigation * flow behavior * particle size distribution effect * pressure drop Subject RIV: BK - Fluid Dynamics Impact factor: 0.545, year: 2011

Real-time aerosol photometer and optical particle counter comparison

International Nuclear Information System (INIS)

Santi, E.; Belosi, F.; Santachiara, G.; Prodi, F.; Berico, M.

2010-01-01

The paper presents the results of a comparison exercise among real-time aerosol samplers, based on different light scattering techniques. The comparison was carried out near to the ISAC institute in a box positioned inside the CNR research area in Bologna. Two nephelometers (Dust Trak from TSI, and Air Genius from Unitec) and an optical particle counter (ENVIRO-check from Grimm) were used for P M1 and P M10 fraction assessment. In the case of the optical particle counter, the particle number concentration in each size bin was also used. In parallel, two manual sampling lines were employed for reference (gravimetric) measurements. The results highlight different factor scales for the dust monitors, in comparison with gravimetric assessment, underlining the importance of a user calibration of such monitors as a function of the specific aerosol sampled. Moreover, the relative fluctuations of the hourly P M 10 and P M1 concentrations, against daily average concentrations, were studied in order to compare the ability of each sampler to follow changes in the aerosol size distribution. It was found that the photometers and optical particle counter revealed different behaviours. In the latter, a small increase in the particle concentration number in the coarse fraction gave a relatively high increase in the mass concentration that was not measured by the photometers. The explanation could be the relatively slight influence of a small particle number variation on the total scattered light for the photometers, unlike the case of the optical particle counter, where each particle contributes to the mass concentration. This aspect merits future research in order to better understand optical particle counter output used in P Mx monitoring activities.

Particle size distribution and total solids suspension in samples monitoring of capturing water for optimization of water injection filtration system; Monitoramento da quantidade de particulas e do total de solidos em suspensao em amostras de agua de captacao

Energy Technology Data Exchange (ETDEWEB)

Ramalhao, Adriano Gorga; Seno, Carlos Eduardo; Ribeiro, Alice [3M do Brasil, Sumare, SP (Brazil)

2008-07-01

There is a wide variation in the amount of particulate material in sea water by a great number of reasons. The most well-known contaminant is the organic material derived from seaweed or fish spawning causing seasonally sensitive variations in the water quality treated and injected for enhance oil recovery. This paper presents the results of one year the water monitoring form water sampled at 30 meters deep in the Roncador field, which is located 125 km from the coast with a depth of 1290 meters. It was observed the water seasonal variation with peaks in summer and winter. The monitoring was done through particle counting and distribution analysis and total solids in suspension. It was noted that even in peak with largest amount of particles and greater quantity of solid in suspension the particles had remained concentrated in the range bellow 25 {mu}m. For that reason the life of final filter elements may vary and pre-filters are many times ineffective and sometimes even bypassed due to frequent clogging and not to do the protecting job of the final filter. (author)

Concentration and vertical flux of Fukushima-derived radiocesium in sinking particles from two sites in the Northwestern Pacific Ocean

Directory of Open Access Journals (Sweden)

M. C. Honda

2013-06-01

Full Text Available At two stations in the western North Pacific, K2 in the subarctic gyre and S1 in the subtropical gyre, time-series sediment traps were collecting sinking particles when the Fukushima Daiichi Nuclear Power Plant (FNPP1 accident occurred on 11 March 2011. Radiocesium (134Cs and 137Cs derived from the FNPP1 accident was detected in sinking particles collected at 500 m in late March 2011 and at 4810 m in early April 2011 at both stations. The sinking velocity of 134Cs and 137Cs was estimated to be 22 to 71 m day−1 between the surface and 500 m and >180 m day−1 between 500 m and 4810 m. 137Cs concentrations varied from 0.14 to 0.25 Bq g−1 dry weight. These values are higher than those of surface seawater, suspended particles, and zooplankton collected in April 2011. Although the radiocesium may have been adsorbed onto or incorporated into clay minerals, correlations between 134Cs and lithogenic material were not always significant; therefore, the form of the cesium associated with the sinking particles is still an open question. The total 137Cs inventory by late June at K2 and by late July at S1 was 0.5 to 1.7 Bq m−2 at both depths. Compared with 137Cs input from both stations by April 2011, estimated from the surface 137Cs concentration and mixed-layer depth and by assuming that the observed 137Cs flux was constant throughout the year, the estimated removal rate of 137Cs from the upper layer (residence time in the upper layer was 0.3 to 1.5% yr−1 (68 to 312 yr. The estimated removal rates and residence times are comparable to previously reported values after the Chernobyl accident (removal rate: 0.2–1%, residence time: 130–390 yr.

Effect of size and concentration of silt particles on erosion of Pelton turbine buckets

Energy Technology Data Exchange (ETDEWEB)

Padhy, M.K.; Saini, R.P. [Alternate Hydro Energy Centre, Indian Institute of Technology Roorkee, Roorkee (India)

2009-10-15

Erosive wear of hydro turbine runners depends upon different parameters such as size, hardness and concentration of silt particles, velocity of flow, properties of the base material of the turbine components and operating hours of the turbine. Various researchers have conducted experiments to study the effect of these parameters on erosive wear. Most of these experiments were on small-size samples at different types of test rigs to simulate the flow conditions in turbines, however actual flow conditions and the phenomenon of erosive wear are too complex to simulate. Under the present study, effect of these parameters on erosion in actual conditions has been investigated experimentally. An extensive experimental study has been carried out on a small scale Pelton turbine. Based on the experimental data collected for different parameters, correlations have been developed for wear rate of Pelton turbine buckets as a function of critical parameters, i.e., size and concentration of silt particles and jet velocity. (author)

Exposure assessment of workplace manufacturing titanium dioxide particles

Energy Technology Data Exchange (ETDEWEB)

Xu, Huadong; Zhao, Lin; Chen, Zhangjian [Peking University, Department of Occupational and Environmental Health Sciences, School of Public Health (China); Zhou, Jingwen [Jinan Center for Disease Control and Prevention (China); Tang, Shichuan [Beijing Municipal Institute of Labor Protection, Beijing Key Laboratory of Occupational Safety and Health (China); Kong, Fanling [Shandong Center for Disease Control and Prevention (China); Li, Xinwei; Yan, Ling; Zhang, Ji, E-mail: zhangji1967@163.com [Jinan Center for Disease Control and Prevention (China); Jia, Guang, E-mail: jiaguangjia@bjmu.edu.cn [Peking University, Department of Occupational and Environmental Health Sciences, School of Public Health (China)

2016-10-15

With the widespread use of titanium dioxide (TiO{sub 2}) human exposure is inevitable, but the exposure data on TiO{sub 2} are still limited. This study adopted off-line filter-based sampling combined with real-time activity-based monitoring to measure the concentrations in a workplace manufacturing TiO{sub 2} (primary diameter: 194 ± 108 nm). Mass concentrations (MCs) of aerosol particles in the packaging workshop (total dust: 3.17 mg/m{sup 3}, nano dust: 1.22 mg/m{sup 3}) were much higher than those in the milling workshop (total dust: 0.79 mg/m{sup 3}, nano dust: 0.31 mg/m{sup 3}) and executive office (total dust: 0.44 mg/m{sup 3}, nano dust: 0.19 mg/m{sup 3}). However, the MCs of TiO{sub 2} were at a relatively low level in the packaging workshop (total TiO{sub 2}: 46.4 μg/m{sup 3}, nano TiO{sub 2}: 16.7 μg/m{sup 3}) and milling workshop (total TiO{sub 2}: 39.4 μg/m{sup 3}, nano TiO{sub 2}: 19.4 μg/m{sup 3}) by ICP-MS. The number concentration (NC), surface area concentration (SAC) of aerosol particles potentially deposited in alveolar (SAC{sub A}), and tracheobronchial (SAC{sub TB}) regions of lungs in the packaging workshop were (1.04 ± 0.89) × 10{sup 5} particles/cm{sup 3}, 414.49 ± 395.07, and 86.01 ± 83.18 μm{sup 2}/cm{sup 3}, respectively, which were all significantly higher than those of the milling workshop [(0.12 ± 0.40) × 10{sup 5} particles/cm{sup 3}, 75.38 ± 45.23, and 17.60 ± 9.22 μm{sup 2}/cm{sup 3}, respectively] as well as executive office and outdoor background (p < 0.05). Activity-related characteristics were found in both workshops, and the time-variant characteristics showed very similar trends for 3 days in the packaging workshop. Our study provides important data of TiO{sub 2} particles exposure in the workplace.

Elemental Spatiotemporal Variations of Total Suspended Particles in Jeddah City

Directory of Open Access Journals (Sweden)

Mohammad W. Kadi

2014-01-01

Full Text Available Elements associated with total suspended particulate matter (TSP in Jeddah city were determined. Using high-volume samplers, TSP samples were simultaneously collected over a one-year period from seven sampling sites. Samples were analyzed for Al, Ba, Ca, Cu, Mg, Fe, Mn, Zn, Ti, V, Cr, Co, Ni, As, and Sr. Results revealed great dependence of element contents on spatial and temporal variations. Two sites characterized by busy roads, workshops, heavy population, and heavy trucking have high levels of all measured elements. Concentrations of most elements at the two sites exhibit strong spatial gradients and concentrations of elements at these sites are higher than other locations. The highest concentrations of elements were observed during June–August because of dust storms, significant increase in energy consumption, and active surface winds. Enrichment factors of elements at the high-level sites have values in the range >10~60 while for Cu and Zn the enrichment factors are much higher (~0–>700 indicating that greater percentage of TSP composition for these three elements in air comes from anthropogenic activities.

Total dissolved atmospheric nitrogen deposition in the anoxic Cariaco basin

Science.gov (United States)

Rasse, R.; Pérez, T.; Giuliante, A.; Donoso, L.

2018-04-01

Atmospheric deposition of total dissolved nitrogen (TDN) is an important source of nitrogen for ocean primary productivity that has increased since the industrial revolution. Thus, understanding its role in the ocean nitrogen cycle will help assess recent changes in ocean biogeochemistry. In the anoxic Cariaco basin, the place of the CARIACO Ocean Time-Series Program, the influence of atmospherically-deposited TDN on marine biogeochemistry is unknown. In this study, we measured atmospheric TDN concentrations as dissolved organic (DON) and inorganic (DIN) nitrogen (TDN = DIN + DON) in atmospheric suspended particles and wet deposition samples at the northeast of the basin during periods of the wet (August-September 2008) and dry (March-April 2009) seasons. We evaluated the potential anthropogenic N influences by measuring wind velocity and direction, size-fractionated suspended particles, chemical traces and by performing back trajectories. We found DIN and DON concentration values that ranged between 0.11 and 0.58 μg-N m-3 and 0.11-0.56 μg-N m-3 in total suspended particles samples and between 0.08 and 0.54 mg-N l-1 and 0.02-1.3 mg-N l-1 in wet deposition samples, respectively. Continental air masses increased DON and DIN concentrations in atmospheric suspended particles during the wet season. We estimate an annual TDN atmospheric deposition (wet + particles) of 3.6 × 103 ton-N year-1 and concluded that: 1) Atmospheric supply of TDN plays a key role in the C and N budget of the basin because replaces a fraction of the C (20% by induced primary production) and N (40%) removed by sediment burial, 2) present anthropogenic N could contribute to 30% of TDN atmospheric deposition in the basin, and 3) reduced DON (gas + particles) should be a significant component of bulk N deposition.

Chlorine disinfection of grey water for reuse: effect of organics and particles.

Science.gov (United States)

Winward, Gideon P; Avery, Lisa M; Stephenson, Tom; Jefferson, Bruce

2008-01-01

Adequate disinfection of grey water prior to reuse is important to prevent the potential transmission of disease-causing microorganisms. Chlorine is a widely utilised disinfectant and as such is a leading contender for disinfection of grey water intended for reuse. This study examined the impact of organics and particles on chlorine disinfection of grey water, measured by total coliform inactivation. The efficacy of disinfection was most closely linked with particle size. Larger particles shielded total coliforms from inactivation and disinfection efficacy decreased with increasing particle size. Blending to extract particle-associated coliforms (PACs) following chlorine disinfection revealed that up to 91% of total coliforms in chlorinated grey water were particle associated. The organic concentration of grey water affected chlorine demand but did not influence the disinfection resistance of total coliforms when a free chlorine residual was maintained. Implications for urban water reuse are discussed and it is recommended that grey water treatment systems target suspended solids removal to ensure removal of PACs prior to disinfection.

Seasonal variations of total {sup 234}Th and dissolved {sup 238}U concentration activities in surface water of Bransfield Strait, Antarctica, from March to October 2011

Energy Technology Data Exchange (ETDEWEB)

Lapa, Flavia V.; Oliveira, Joselene de; Costa, Alice M.R., E-mail: fvlapa@ipen.br, E-mail: jolivei@ipen.br, E-mail: lice_mrc@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil). Laboratorio de Radiometria Ambiental; Braga, Elisabete S., E-mail: edsbraga@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Inst. Oceanografico. Lab. de Nutrientes, Micronutrientes e Tracos nos Oceanos

2013-07-01

In this study the naturally occurring radionuclides {sup 234}Th and {sup 238}U were used to investigate the magnitude of upper ocean particulate organic carbon export in Bransfield Strait, Southern Ocean. This region is the largest oceanic high-nitrate low-chlorophyll (HNLC) area in the world and is known to contribute to regulate of the atmospheric CO{sub 2} via the biological pump. Due to its different geochemical behavior in seawater, the resulting U/Th disequilibria can be easily used to constrain the transport rates of particles and reaction processes between solution and particulate phases. Sampling occurred during the summer (March and November) 2011. Total {sup 234}Th activities in surface seawater samples ranged from 1.3 to 3.7 dpm L{sup -1} (station EB 011) during March/11 campaign, while in October/11 total {sup 234}Th activity concentrations varied from 1.4 to 2.9 dpm L{sup -1}. Highest total {sup 234}Th activities were found late in the austral summer season. Activity concentrations of dissolved {sup 238}U in surface seawater varied from 2.1 to 2.4 dpm L{sup -1}. Taking into account all sampling stations established in March and October/11 the relative variability of total {sup 234}Th distribution was 22%. (author)

Particle concentrating and sorting under a rotating electric field by direct optical-liquid heating in a microfluidics chip.

Science.gov (United States)

Chen, Yu-Liang; Jiang, Hong-Ren

2017-05-01

We demonstrate a functional rotating electrothermal technique for rapidly concentrating and sorting a large number of particles on a microchip by the combination of particle dielectrophoresis (DEP) and inward rotating electrothermal (RET) flows. Different kinds of particles can be attracted (positive DEP) to or repelled (negative DEP) from electrode edges, and then the n-DEP responsive particles are further concentrated in the heated region by RET flows. The RET flows arise from the spatial inhomogeneous electric properties of fluid caused by direct infrared laser (1470 nm) heating of solution in a rotating electric field. The direction of the RET flows is radially inward to the heated region with a co-field (the same as the rotating electric field) rotation. Moreover, the velocity of the RET flows is proportional to the laser power and the square of the electric field strength. The RET flows are significant over a frequency range from 200 kHz to 5 MHz. The RET flows are generated by the simultaneous application of the infrared laser and the rotating electric field. Therefore, the location of particle concentrating can be controlled within the rotating electric field depending on the position of the laser spot. This multi-field technique can be operated in salt solutions and at higher frequency without external flow pressure, and thus it can avoid electrokinetic phenomena at low frequency to improve the manipulation accuracy for lab-on-chip applications.

Distribution of Total Suspended Solids Concentration in a River

Directory of Open Access Journals (Sweden)

Ahmad Hanif Asyhar

2012-08-01

Full Text Available Disposal of either industrial or nonindustrial wastewater into a river has a potential to cause riverpollution. Because each load of wastewater discharged into a river contains physical, chemical, and biological parametersthat determine water quality, so that it can affect the dissolved oxygen concentration in a river. Therefore the conductedresearch was aimed to determine the pattern of pollutant dispersion in Surabaya River within the section that is closed tothe Karang Pilang Monitoring Station - Surabaya. Parameter used in this research was Total Suspended Solids (TSS. Themethod used was the finite volume method with Quadratic Upwind Interpolation Convective Kinematics (QUICK schemeby means of developing models of dispersion water pollutants in a river. The governing equation was controlled by the lawsof mass conservation, momentum conservation, and pollution transport equation. Further, these equations were solvedusing numerical calculation and followed by numerical simulation. From the numerical simulation results, it can beconcluded that the magnitude of pollutant dispersion is determined by the initial discharged TSS concentrations into theriver, however the longitudinal direction is more dominantly influenced than in lateral directions.

Anthropogenic Influence on Secondary Aerosol Formation and Total Water-Soluble Carbon on Atmospheric Particles

Science.gov (United States)

Gioda, Adriana; Mateus, Vinicius; Monteiro, Isabela; Taira, Fabio; Esteves, Veronica; Saint'Pierre, Tatiana

2013-04-01

On a global scale, the atmosphere is an important source of nutrients, as well as pollutants, because of its interfaces with soil and water. Important compounds in the gaseous phase are in both organic and inorganic forms, such as organic acids, nitrogen, sulfur and chloride. In spite of the species in gas form, a huge number of process, anthropogenic and natural, are able to form aerosols, which may be transported over long distances. Sulfates e nitrates are responsible for rain acidity; they may also increase the solubility of organic compounds and metals making them more bioavailable, and also can act as cloud condensation nuclei (CCN). Aerosol samples (PM2.5) were collected in a rural and industrial area in Rio de Janeiro, Brazil, in order to quantify chemical species and evaluate anthropogenic influences in secondary aerosol formation and organic compounds. Samples were collected during 24 h every six days using a high-volume sampler from August 2010 to July 2011. The aerosol mass was determined by Gravimetry. The water-soluble ionic composition (WSIC) was obtained by Ion Chromatography in order to determine the major anions (NO3-, SO4= and Cl-); total water-soluble carbon (TWSC) was determined by a TOC analyzer. The average aerosol (PM2.5) concentrations ranged from 1 to 43 ug/m3 in the industrial site and from 4 to 35 ug/m3 in the rural area. Regarding anions, the highest concentrations were measured for SO42- (10.6 μg/m3-12.6 μg/m3); where the lowest value was found in the rural site and the highest in the industrial. The concentrations for NO3- and Cl- ranged from 4.2 μg/m3 to 9.3 μg/m3 and 3.1 μg/m3 to 6.4 μg /m3, respectively. Sulfate was the major species and, like nitrate, it is related to photooxidation in the atmosphere. Interestingly sulfate concentrations were higher during the dry period and could be related to photochemistry activity. The correlations between nitrate and non-sea-salt sulfate were weak, suggesting different sources for these

Improved concentration and separation of particles in a 3D dielectrophoretic chip integrating focusing, aligning and trapping

KAUST Repository

Li, Ming

2012-10-18

This article presents a dielectrophoresis (DEP)-based microfluidic device with the three-dimensional (3D) microelectrode configuration for concentrating and separating particles in a continuous throughflow. The 3D electrode structure, where microelectrode array are patterned on both the top and bottom surfaces of the microchannel, is composed of three units: focusing, aligning and trapping. As particles flowing through the microfluidic channel, they are firstly focused and aligned by the funnel-shaped and parallel electrode array, respectively, before being captured at the trapping unit due to negative DEP force. For a mixture of two particle populations of different sizes or dielectric properties, with a careful selection of suspending medium and applied field, the population exhibits stronger negative DEP manipulated by the microelectrode array and, therefore, separated from the other population which is easily carried away toward the outlet due to hydrodynamic force. The functionality of the proposed microdevice was verified by concentrating different-sized polystyrene (PS) microparticles and yeast cells dynamically flowing in the microchannel. Moreover, separation based on size and dielectric properties was achieved by sorting PS microparticles, and isolating 5 μm PS particles from yeast cells, respectively. The performance of the proposed micro-concentrator and separator was also studied, including the threshold voltage at which particles begin to be trapped, variation of cell-trapping efficiency with respect to the applied voltage and flow rate, and the efficiency of separation experiments. The proposed microdevice has various advantages, including multi-functionality, improved manipulation efficiency and throughput, easy fabrication and operation, etc., which shows a great potential for biological, chemical and medical applications. © 2012 Springer-Verlag Berlin Heidelberg.

Determining the most effective concentration of cypermethrin and the appropriate carrier particle size for fire ant (Hymenoptera: Formicidae) bait.

Science.gov (United States)

Kafle, Lekhnath; Shih, Cheng-Jen

2012-03-01

The purpose of this study was to determine the most effective particle size of DDGS (distiller's dried grains with solubles) as fire ant bait carrier, as well as the most effective concentration of cypermethrin as a toxicant against the red imported fire ant (RIFA) Solenopsis invicta Buren under laboratory conditions. The DDGS particle size did not affect the fire ant's preference for the bait, but it did affect the mass of DDGS being carried back to the nest. The size of the DDGS particles and the mass of DDGS being carried back to the nest were positively correlated. The most efficient particle size of DDGS was 0.8-2 mm. The concentration of cypermethrin has a specific range for killing fire ants in an efficient manner. Neither a very low nor a very high concentration of cypermethrin was able to kill fire ants efficiently. The most effective concentration of cypermethrin was 0.13% in DDGS when mixed with 15% shrimp shell powders and 11% soybean oil. Based on its ability to kill fire ants when mixed with cypermethrin, as well as the advantage of having a larger area coverage when sprayed in the field, DDGS as the carrier and cypermethrin as the toxicant can be considered to be an efficient way to prepare fire ant bait for controlling fire ants in infested areas. Copyright © 2012 Society of Chemical Industry.

[Are inhaled dust particles harmful for our lungs?].

Science.gov (United States)

Brändli, O

1996-12-14

Particles with diameters ranging from less than 0.02 to more than 100 microns and in concentration up to 120 micrograms/m3 daily average TSP (total suspended particles) are measurable in the air of Swiss cities and responsible for the decrease of visibility on the Swiss Plateau and south of the Alps. The particle size shows a typical distribution: the coarse particles (> 2.5 microns mass median diameter) are mostly of natural origin (plants, pollen, earth particles) and are deposited in the upper airways. The fine particles (PM2.5 annual concentrations of 14-53 micrograms/m3 TSP or 10-33 micrograms/m3 PM10, well below the national standard (annual mean TSP 70 micrograms/m3) have been measured in rural and urban areas. Even at these concentrations an increase in respiratory symptoms and a decrease in lung function, without evidence for a "safe" threshold, have been observed in the Swiss study of air pollution and lung diseases in adults (SAPALDIA). Although the noxious effects of the particles cannot be clearly separated from the effect of other pollutants (e.g. NOx, SO2, ozone) in complex pollutant mixtures, the emission standards and national standards for ambient air should be revised, in particular by adding a standard for fine particles (e.g. PM10 or PM2.5).

An Integrated Instrumentation System for Velocity, Concentration and Mass Flow Rate Measurement of Solid Particles Based on Electrostatic and Capacitance Sensors

Directory of Open Access Journals (Sweden)

Jian Li

2015-12-01

Full Text Available The online and continuous measurement of velocity, concentration and mass flow rate of pneumatically conveyed solid particles for the high-efficiency utilization of energy and raw materials has become increasingly significant. In this paper, an integrated instrumentation system for the velocity, concentration and mass flow rate measurement of dense phase pneumatically conveyed solid particles based on electrostatic and capacitance sensorsis developed. The electrostatic sensors are used for particle mean velocity measurement in combination with the cross-correlation technique, while the capacitance sensor with helical surface-plate electrodes, which has relatively homogeneous sensitivity distribution, is employed for the measurement of particle concentration and its capacitance is measured by an electrostatic-immune AC-based circuit. The solid mass flow rate can be further calculated from the measured velocity and concentration. The developed instrumentation system for velocity and concentration measurement is verified and calibrated on a pulley rig and through static experiments, respectively. Finally the system is evaluated with glass beads on a gravity-fed rig. The experimental results demonstrate that the system is capable of the accurate solid mass flow rate measurement, and the relative error is within −3%–8% for glass bead mass flow rates ranging from 0.13 kg/s to 0.9 kg/s.

Particle Emissions from Biomass Combustion

Energy Technology Data Exchange (ETDEWEB)

Szpila, Aneta; Bohgard, Mats [Lund Inst. of Technology (Sweden). Div. of Ergonomics and Aerosol Technology; Strand, Michael; Lillieblad, Lena; Sanati, Mehri [Vaexjoe Univ. (Sweden). Div. of Bioenergy Technology; Pagels, Joakim; Rissler, Jenny; Swietlicki, Erik; Gharibi, Arash [Lund Univ. (Sweden). Div. of Nuclear Physics

2003-05-01

particle number concentration increased slightly with increasing load, at the same time the fine mode particles became smaller. This was probably caused by different degree of particle coagulation as the residence time in the boiler was changed. The mean diameter during combustion of forest residue was around 100 nm compared to 70-80 nm for dry wood and pellets, while the total number was close to constant. This explains the differences in mass concentration found in the impactor measurements. The concentrations of CO and THC was highest for the dry wood fuel, the PAH concentration was highest for pellets combustion in boiler 4, however this boiler was poorly tuned at the time of measurement. The PAH concentration was 5 times higher during combustion of dry wood compared to forest residue. The concentration of CO, THC and PAH varied to a great extend. The high concentrations were measured in boilers running at a low load. The concentration of particle organic carbon was less than 15% of PMI for all fuels. However we used heated primary dilution, which inhibits the condensation of organic components into, the particle phase. A significant fraction of the emitted organic carbon may condense to the particle phase during dilution after the stack or after being oxidized in the atmosphere. We also measured elemental carbon in the particle phase. The contribution to PM1 was as high as 25-30% during pellets combustion at low load and 8% at low load during combustion of dry wood. In all other cases the EC-concentration was less than 3% of PMI. PIXE and lon-chromatography confirmed that alkali-salts were the dominant chemical species. PIXE analysis revealed that emitted amounts of heavy metals such as Zn, Cd and Pb are strongly dependent on the type of the fuel used. Forest residues gave high emissions of Zn, Cd and Pb, while pellets gave very high emissions of Cd and Zn. The fuel with the lowest emissions of heavy metals was dry wood. This again could be related to ash content in

Influence of starter culture on total free aminoacids concentration during ripening of Krk cheese

Directory of Open Access Journals (Sweden)

Biljana Radeljević

2013-03-01

Full Text Available The aim of this study was to determine the influence of microbial (commercial starter culture on concentration of total free amino groups (amino acids in cheeses in different ripening stages. Free amino groups were determined by reaction with ninhydrin with cadmium (Cd in the water soluble cheese extract, and were expressed as the concentration of leucine in cheese dry matter. Changes in concentration of total free amino acids during cheese ripening (0th, 30th, 60th, 90th and 120th day were monitored. In water soluble extracts of cheese, the presence of free NH2 groups in all ripening stages was detected, which means smaller peptides and amino acids, whose concentration significantly (P<0.01 increased during ripening. Cheeses produced with and without microbial culture resulted in statistically significant differences (P<0.01 in content amino acids free on the 90th and 120th day of ripening. Cd - ninhydrin method was found to be suitable for cheese ripening monitoring, as well as for determination of the differences in mature characteristics of cheeses, depending on the production process.

Particle size distributions, size concentration relationships, and adherence to hands of selected geologic media derived from mining, smelting, and quarrying activities

Energy Technology Data Exchange (ETDEWEB)

Bergstrom, Carolyn; Shirai, Jeffry; Kissel, John, E-mail: jkissel@uw.edu

2011-09-15

Hand-to-mouth activity, especially in children, is a potentially significant pathway of exposure to soil contaminants. Hand-mouthing behavior is of particular concern in areas impacted by mining, smelting, and quarrying activities as these activities may lead to elevated levels of heavy metals in soil. In order to estimate potential exposures to contaminated geologic media attributable to hand-to-mouth contact, it is useful to characterize adherence of those media to skin, as contaminant concentrations in adhered media may differ greatly from unfractionated, whole media concentrations. Such an investigation has been undertaken to aid estimation of exposures to arsenic, cadmium, lead, and zinc in nine different geologic media collected in the Pacific Northwest region of the United States. After establishing the particle size distribution of each medium (fractions < 63 {mu}m, 63-150 {mu}m, 150-250 {mu}m, and 250 {mu}m-2 mm were determined) and target elemental concentrations within each particle size fraction, an active handling protocol involving six volunteers was conducted. Wet media always adhered to a greater extent than dry media and adhered media generally had higher elemental concentrations than bulk media. Regression analyses suggest smaller particle fractions may have higher elemental concentrations. Results of application of a maximum likelihood estimation technique generally indicate that handling of dry media leads to preferential adherence of smaller particle sizes, while handling of wet media does not. Because adhered material can differ greatly in particle size distribution from that found in bulk material, use of bulk concentrations in exposure calculations may lead to poor estimation of actual exposures. Since lead has historically been a metal of particular concern, EPA's Integrated Exposure Uptake Biokinetic (IEUBK) Model was used to examine the potential consequences of evaluating ingestion of the selected media assuming concentrations in

Flow behaviour and local concentration of coarse particles-water mixture in inclined pipes

Czech Academy of Sciences Publication Activity Database

Vlasák, Pavel; Chára, Zdeněk; Konfršt, Jiří

2017-01-01

Roč. 65, č. 2 (2017), s. 183-191 ISSN 0042-790X R&D Projects: GA ČR GAP105/10/1574 Institutional support: RVO:67985874 Keywords : coarse particle mixture * concentration distribution * effect of pipe inclination * gamma-ray radiometry * Hydraulic conveying * mixture flow behaviour Subject RIV: BK - Fluid Dynamics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 1.654, year: 2016

Free and total urinary phthalate metabolite concentrations among pregnant women from the Healthy Baby Cohort (HBC), China.

Science.gov (United States)

Zhu, Yingshuang; Wan, Yanjian; Li, Yuanyuan; Zhang, Bin; Zhou, Aifen; Cai, Zongwei; Qian, Zhengmin; Zhang, Chuncao; Huo, Wenqian; Huang, Kai; Hu, Jie; Cheng, Lu; Chang, Huailong; Huang, Zheng; Xu, Bing; Xia, Wei; Xu, Shunqing

2016-03-01

Total urinary phthalate metabolites (the free plus glucuronidated forms) have been frequently measured in the general population. However, data are limited on the free forms which may be more bioactive, especially for sensitive population such as pregnant women. Here the data gap was addressed by measuring concentrations of free and total forms of six phthalate metabolites in 293 urine samples from pregnant women at delivery, who were randomly selected from the prospective Healthy Baby Cohort (HBC), China. We observed detectable concentrations of the total amount of phthalate metabolites in all urine samples. The geometric mean (GM) urinary concentrations of free and total mono-butyl phthalate (MBP) (5.20, 54.49ng/mL) were the highest, followed by mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP) (4.52, 7.27ng/mL). For most of phthalate metabolites, urinary concentrations were significantly higher in women who were nulliparous. Significantly higher concentrations of mono-ethyl phthalate (MEP) and mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) were found in women who had higher educational level. To our knowledge, this is the first study to report the free and total forms of phthalate metabolites among pregnant women in China. The results suggest that exposure characteristics may be related to parity and education. Copyright © 2015 Elsevier Ltd. All rights reserved.

Measurement of the atmospheric aerosol particle size distribution in a highly polluted mega-city in Southeast Asia (Dhaka-Bangladesh)

Science.gov (United States)

Salam, Abdus; Mamoon, Hassan Al; Ullah, Md. Basir; Ullah, Shah M.

2012-11-01

Aerosol particle size distribution was measured with an aerodynamic particle sizer (APS) spectrometer continuously from January 21 to April 24, 2006 in Dhaka, Bangladesh. Particles number, surface and mass distributions data were stored automatically with Aerosol Instrument Manager (AIM) software on average every half an hour in a computer attached to the APS. The grand total average of number, surface and mass concentrations were 8.2 × 103 ± 7.8 × 103 particles cm-3, 13.3 × 103 ± 11.8 × 103 μm2 cm-3 and 3.04 ± 2.10 mg m-3, respectively. Fine particles with diameter smaller than 1.0 μm aerodynamic diameter (AD) dominated the number concentration, accounted for 91.7% of the total particles indicating vehicular emissions were dominating in Dhaka air either from fossil fuel burning or compressed natural gas (CNGs). The surface and mass concentrations between 0.5 and 1.0 μm AD were about 56.0% and 26.4% of the total particles, respectively. Remarkable seasonal differences were observed between winter and pre-monsoon seasons with the highest monthly average in January and the lowest in April. Aerosol particles in winter were 3.79 times higher for number, 3.15 times for surface and 2.18 times for mass distributions than during the pre-monsoon season. Weekends had lower concentrations than weekdays due to less vehicular traffic in the streets. Aerosol particles concentrations were about 15.0% (ranging from 9.4% to 17.3%) higher during traffic peak hours (6:00am-8:00pm) than off hours (8:00pm-6:00am). These are the first aerosol size distribution measurements with respect to number, surface and mass concentrations in real time at Dhaka, Bangladesh.

Dynamics of Total Microcystin LR Concentration in Three Subtropical Hydroelectric Generation Reservoirs in Uruguay, South America.

Science.gov (United States)

González-Piana, Mauricio; Fabián, Daniel; Piccardo, Andrea; Chalar, Guillermo

2017-10-01

This study analyzed the temporal dynamics of total microcystin LR concentrations between the years of 2012 and 2015 in the Bonete, Baygorria and Palmar hydroelectric generation reservoirs in the central region of the Negro River, Uruguay. The three reservoirs showed differents total microcystin LR concentration, with no significant differences among them. Over 20 sampling dates, the three reservoirs exhibited total microcystin LR concentrations on eight occasions that corresponded to a slight to moderate human health risk according to WHO guideline values for recreational waters. By determining the concentration of microcystin LR in cyanobacterial biomass, we identified cyanobacterial populations that occurred over time with varying degrees of toxin production (maximal 85.4 µg/mm 3 ). The microcystin LR concentration in Bonete was positively correlated with temperature (r = 0.587) and cyanobacterial biomass (r = 0.736), in Baygorria with cyanobacterial biomass (r = 0.521), and in Palmar with temperature (r = 0.500) and negatively correlated with ammonia (r = -0.492). Action is needed to reduce the presence of toxic cyanobacteria in these systems. A decrease in the use of agrochemicals and management changes in the reservoir basins could be successful long-term measures.

Total Particle Number Emissions from Modern Diesel, Natural Gas, and Hybrid Heavy-Duty Vehicles During On-Road Operation.

Science.gov (United States)

Wang, Tianyang; Quiros, David C; Thiruvengadam, Arvind; Pradhan, Saroj; Hu, Shaohua; Huai, Tao; Lee, Eon S; Zhu, Yifang

2017-06-20

Particle emissions from heavy-duty vehicles (HDVs) have significant environmental and public health impacts. This study measured total particle number emission factors (PNEFs) from six newly certified HDVs powered by diesel and compressed natural gas totaling over 6800 miles of on-road operation in California. Distance-, fuel- and work-based PNEFs were calculated for each vehicle. Distance-based PNEFs of vehicles equipped with original equipment manufacturer (OEM) diesel particulate filters (DPFs) in this study have decreased by 355-3200 times compared to a previous retrofit DPF dynamometer study. Fuel-based PNEFs were consistent with previous studies measuring plume exhaust in the ambient air. Meanwhile, on-road PNEF shows route and technology dependence. For vehicles with OEM DPFs and Selective Catalytic Reduction Systems, PNEFs under highway driving (i.e., 3.34 × 10 12 to 2.29 × 10 13 particles/mile) were larger than those measured on urban and drayage routes (i.e., 5.06 × 10 11 to 1.31 × 10 13 particles/mile). This is likely because a significant amount of nucleation mode volatile particles were formed when the DPF outlet temperature reached a critical value, usually over 310 °C, which was commonly achieved when vehicle speed sustained over 45 mph. A model year 2013 diesel HDV produced approximately 10 times higher PNEFs during DPF active regeneration events than nonactive regeneration.

Total deposition of inhaled particles related to age: comparison with age-dependent model calculations

International Nuclear Information System (INIS)

Becquemin, M.H.; Bouchikhi, A.; Yu, C.P.; Roy, M.

1991-01-01

To compare experimental data with age-dependent model calculations, total airway deposition of polystyrene aerosols (1, 2.05 and 2.8 μm aerodynamic diameter) was measured in ten adults, twenty children aged 12 to 15 years, ten children aged 8 to 12, and eleven under 8 years old. Ventilation was controlled, and breathing patterns were appropriate for each age, either at rest or at light exercise. Individually, deposition percentages increased with particle size and also from rest to exercise, except in children under 12 years, in whom they decreased from 20-21.5 to 14-14.5 for 1 μm particles and from 36.8-36.9 to 32.2-33.1 for 2.05 μm particles. Comparisons with the age-dependent model showed that, at rest, the observed data concerning children agreed with those predicted and were close to the adults' values, when the latter were higher than predicted. At exercise, child data were lower than predicted and lower than adult experimental data, when the latter agreed fairly well with the model. (author)

Dependence of the quasipotential on the total energy of a two-particle system

International Nuclear Information System (INIS)

Kapshai, V.N.; Savrin, V.I.; Skachkov, N.B.

1987-01-01

For a system of two relativistic particles described in the Logunov-Tavkhelidze one-time approach the dependence of the quasipotential of one-boson exchange on the total energy of the system is calculated. It is shown that despite the nonlocal form of the obtained quasipotential the three-dimensional equations for the waves function can be reduced by a partial expansion to one-dimensional equations. The influence of the energy dependence of the quasipotential on its behavior in the coordinate representation is discussed

Effect of (Cd:ZnS Particle Concentration and Photoexcitation on the Electrical and Ferroelectric Properties of (Cd:ZnS/P(VDF-TrFE Composite Films

Directory of Open Access Journals (Sweden)

Sebastian Engel

2017-11-01

Full Text Available The influence of semiconductor particle concentration and photoexcitation on the electrical and ferroelectric properties of ferroelectric-semiconductor-composites was investigated. For this purpose, 32 µm thin films of poly(vinylidene fluoride-co-trifluoroethylene with (Cd:ZnS particle concentrations of between 0 and 20 vol % were fabricated and characterized by scanning electron microscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, and optical spectroscopy. It was shown that the particle concentration has only a negligible influence on the molecular structure of the polymer but strongly determines the optical properties of the composite. For (Cd:ZnS particle concentrations below 20 vol %, the I-V characteristics of the composites is only marginally affected by the particle concentration and the optical excitation of the composite material. On the contrary, a strong influence of both parameters on the ferro- and pyroelectric properties of the composite films was observed. For particle fractions that exhibit ferroelectric hysteresis, an increased remanent polarization and pyroelectric coefficient due to optical excitation was obtained. A theoretical approach that is based on a “three phase model” of the internal structure was developed to explain the observed results.

The Contribution of Black Carbon to Ice Nucleating Particle Concentrations from Prescribed Burns and Wildfires

Science.gov (United States)

Schill, G. P.; DeMott, P. J.; Suski, K. J.; Emerson, E. W.; Rauker, A. M.; Kodros, J.; Levin, E. J.; Hill, T. C. J.; Farmer, D.; Pierce, J. R.; Kreidenweis, S. M.

2017-12-01

Black carbon (BC) has been implicated as a potential immersion-mode ice nucleating particle (INP) because of its relative abundance in the upper troposphere. Furthermore, several field and aircraft measurements have observed positive correlations between BC and INP concentrations. Despite this, the efficiency of BC to act as an immersion-mode INP is poorly constrained. Indeed, previous results from laboratory studies are in conflict, with estimates of BC's impact on INP ranging from no impact to being efficient enough to rival the well-known INP mineral dust. It is, however, becoming clear that the ice nucleation activity of BC may depend on both its fuel type and combustion conditions. For example, previous work has shown that diesel exhaust BC is an extremely poor immersion-mode INP, but laboratory burns of biomass fuels indicate that BC can contribute up to 70% of all INP for some fuel types. Given these dependencies, we propose that sampling from real-world biomass burning sources would provide the most useful new information on the contribution of BC to atmospheric INP. In this work, we will present recent results looking at the sources of INP from prescribed burns and wildfires. To determine the specific contribution of refractory black carbon (rBC) to INP concentrations, we utilized a new technique that couples the Single Particle Soot Photometer (SP2) to the Colorado State University Continuous Flow Diffusion Chamber (CFDC). The SP2 utilizes laser-induced incandescence to quantify rBC mass on a particle-by-particle basis; in doing so, it also selectively destroys rBC particles by heating them to their vaporization temperature. Thus, the SP2 can be used as a selective pre-filter for rBC into the CFDC. Furthermore, we have also used a filter-based technique for measuring INP, the Ice Spectrometer, which can employ pretreatments such as heating and digestion by H2O2 to determine the contribution of heat-labile and organic particles, respectively.

Investigating the size, shape and surface roughness dependence of polarization lidars with light-scattering computations on real mineral dust particles: Application to dust particles' external mixtures and dust mass concentration retrievals

Science.gov (United States)

Mehri, Tahar; Kemppinen, Osku; David, Grégory; Lindqvist, Hannakaisa; Tyynelä, Jani; Nousiainen, Timo; Rairoux, Patrick; Miffre, Alain

2018-05-01

Our understanding of the contribution of mineral dust to the Earth's radiative budget is limited by the complexity of these particles, which present a wide range of sizes, are highly-irregularly shaped, and are present in the atmosphere in the form of particle mixtures. To address the spatial distribution of mineral dust and atmospheric dust mass concentrations, polarization lidars are nowadays frequently used, with partitioning algorithms allowing to discern the contribution of mineral dust in two or three-component particle external mixtures. In this paper, we investigate the dependence of the retrieved dust backscattering (βd) vertical profiles with the dust particle size and shape. For that, new light-scattering numerical simulations are performed on real atmospheric mineral dust particles, having determined mineralogy (CAL, DOL, AGG, SIL), derived from stereogrammetry (stereo-particles), with potential surface roughness, which are compared to the widely-used spheroidal mathematical shape model. For each dust shape model (smooth stereo-particles, rough stereo-particles, spheroids), the dust depolarization, backscattering Ångström exponent, lidar ratio are computed for two size distributions representative of mineral dust after long-range transport. As an output, two Saharan dust outbreaks involving mineral dust in two, then three-component particle mixtures are studied with Lyon (France) UV-VIS polarization lidar. If the dust size matters most, under certain circumstances, βd can vary by approximately 67% when real dust stereo-particles are used instead of spheroids, corresponding to variations in the dust backscattering coefficient as large as 2 Mm- 1·sr- 1. Moreover, the influence of surface roughness in polarization lidar retrievals is for the first time discussed. Finally, dust mass-extinction conversion factors (ηd) are evaluated for each assigned shape model and dust mass concentrations are retrieved from polarization lidar measurements. From

Observations of the vertical concentrations of aerosol particles in the boundary layer by means of tethered balloon method

Energy Technology Data Exchange (ETDEWEB)

Ishioka, Futoshi; Lee, D.I; Taniguchi, Takashi; Kikuchi,Katsuhiro

1988-09-30

In general, it is difficult to accurately understand the behavior of aerosol particles in the boundary layer above urban areas because aerosol sources are influenced by time-dependent factors and local climate. To overcome this difficulty, a particle counter which can count Mie particles with diameters of 0.3 /mu/m or more in five diameter ranges was installed on a large tehered balloon. With this method, the vertical distribution of aerosol concentration was measured in several areas different in meteorological condition, and the dependence of the particle behavior on particle diameter was studied. As a result, it has been revealed that the results of the observations explained above agree with the results of studies conducted in the past, but that dependence on particle diameter is not significant. 37 references, 21 figures, 1 table.

Physical characterization of aerosol particles during the Chinese New Year’s firework events

Science.gov (United States)

Zhang, Min; Wang, Xuemei; Chen, Jianmin; Cheng, Tiantao; Wang, Tao; Yang, Xin; Gong, Youguo; Geng, Fuhai; Chen, Changhong

2010-12-01

Measurements for particles 10 nm to 10 μm were taken using a Wide-range Particle Spectrometer during the Chinese New Year (CNY) celebrations in 2009 in Shanghai, China. These celebrations provided an opportunity to study the number concentration and size distribution of particles in an especial atmospheric pollution situation due to firework displays. The firework activities had a clear contribution to the number concentration of small accumulation mode particles (100-500 nm) and PM 1 mass concentration, with a maximum total number concentration of 3.8 × 10 4 cm -3. A clear shift of particles from nucleation and Aitken mode to small accumulation mode was observed at the peak of the CNY firework event, which can be explained by reduced atmospheric lifetimes of smaller particles via the concept of the coagulation sink. High particle density (2.7 g cm -3) was identified as being particularly characteristic of the firework aerosols. Recalculated fine particles PM 1 exhibited on average above 150 μg m -3 for more than 12 hours, which was a health risk to susceptible individuals. Integral physical parameters of firework aerosols were calculated for understanding their physical properties and further model simulation.

Elevated sodium chloride concentrations enhance the bystander effects induced by low dose alpha-particle irradiation

Energy Technology Data Exchange (ETDEWEB)

Han Wei; Zhu Lingyan; Jiang Erkang; Wang Jun; Chen Shaopeng; Bao Linzhi; Zhao Ye; Xu An; Yu Zengliang [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wu Lijun [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)], E-mail: ljw@ipp.ac.cn

2007-11-01

Previous studies have shown that high NaCl can be genotoxic, either alone or combined with irradiation. However, little is known about the relationship between environmental NaCl at elevated conditions and radiation-induced bystander effects (RIBE). RIBE, which has been considered as non-targeted bystander responses, has been demonstrated to occur widely in various cell lines. In the present study, RIBE under the elevated NaCl culture condition was assessed in AG 1522 cells by both the induction of {gamma}-H2AX, a reliable marker of DNA double-strand break (DSB) for the early process (<1 h post irradiation), and the generation of micronuclei (MN), a sensitive marker for relative long process of RIBE. Our results showed that in the absence of irradiation, NaCl at elevated concentration such as 8.0, 9.0 and 10.0 g/L did not significantly increase the frequency of {gamma}-H2AX foci-positive cells and the number of foci per positive cell comparing with that NaCl at a normal concentration (6.8 g/L). However, with 0.2 cGy {alpha}-particle irradiation, the induced fraction of {gamma}-H2AX foci-positive cells and the number of induced {gamma}-H2AX foci per positive cell were significantly increased in both irradiated and adjacent non-irradiated regions. Similarly, the induction of MN by 0.2 cGy {alpha}-particle irradiation also increased with the elevated NaCl concentrations. With N{sup G}-methyl-L-arginine, an inhibitor of nitric oxide synthase, the induced fraction of foci-positive cells was effectively inhibited both in 0.2 cGy {alpha}-particle irradiated and adjacent non-irradiated regions under either normal or elevated NaCl conditions. These results suggested that the cultures with elevated NaCl medium magnified the damage effects induced by the low dose {alpha}-particle irradiation and nitric oxide generated by irradiation was also very important in this process.

Size evolution of ultrafine particles: Differential signatures of normal and episodic events.

Science.gov (United States)

Joshi, Manish; Khan, Arshad; Anand, S; Sapra, B K

2016-01-01

The effect of fireworks on the aerosol number characteristics of atmosphere was studied for an urban mega city. Measurements were made at 50 m height to assess the local changes around the festival days. Apart from the increase in total number concentration and characteristic accumulation mode, short-term increase of ultrafine particle concentration was noted. Total number concentration varies an order of magnitude during the measurement period in which peak occurs at a frequency of approximately one per day. On integral scale, it seems not possible to distinguish an episodic (e.g. firework bursting induced aerosol emission) and a normal (ambient atmospheric changes) event. However these events could be differentiated on the basis of size evolution analysis around number concentration peaks. The results are discussed relative to past studies and inferences are drawn towards aerosol signatures of firework bursting. The short-term burst in ultrafine particle concentration can pose an inhalation hazard. Copyright © 2015 Elsevier Ltd. All rights reserved.

The fine particle emissions of energy production in Finland

International Nuclear Information System (INIS)

Ohlstroem, M.

1998-01-01

The main purpose of this master's thesis was to define the fine particle (PM2.5, diameter under 2,5 μm) emissions of the energy production and to compare the calculated emission factors between different energy production concepts. The purpose was also to define what is known about fine particle emissions and what should still be studied/measured. The purpose was also to compare briefly the fine particle emissions of energy production and vehicle traffic, and their correlations to the fine particle concentrations of urban air. In the theory part of this work a literature survey was made about fine particles in energy production, especially how they form and how they are separated from the flue gas. In addition, the health effects caused by fine particles, and different measuring instruments were presented briefly. In the experimental part of this work, the aim was to find out the fine particle emissions of different energy production processes by calculating specific emission factors (mg/MJ fuel ) from powerplants' annual total particulate matter emissions (t/a), which were obtained from VAHTI-database system maintained by the Finnish Environmental Institute, and by evaluating the share of fine particles from total emissions with the help of existing measurement results. Only those energy production processes which produce significantly direct emissions of solid particles have been treated (pulverised combustion and oil burners from burner combustion, fluidized bed combustion processes, grate boilers, recovery boilers and diesel engines). The processes have been classified according to boiler type, size category, main fuel and also according to dust separation devices. To be able to compare different energy production processes, shared specific emission factor have been calculated for the similar subprocesses. The fine particle emissions depend strongest on the boiler size category and dust separation devices used. Spent fuel or combustion technique does not have

Tree age, fruit size and storage conditions affect levels of ascorbic acid, total phenolic concentrations and total antioxidant activity of 'Kinnow' mandarin juice.

Science.gov (United States)

Khalid, Samina; Malik, Aman U; Khan, Ahmad S; Shahid, Muhammad; Shafique, Muhammad

2016-03-15

Bioactive compounds (ascorbic acid, total phenolics and total antioxidants) are important constituents of citrus fruit juice; however, information with regard to their concentrations and changes in relation to tree age and storage conditions is limited. 'Kinnow' (Citrus nobilis Lour × Citrus deliciosa Tenora) mandarin juice from fruit of three tree ages (6, 18 and 35 years old) and fruit sizes (large, medium and small) were examined for their bioactive compounds during 7 days under ambient storage conditions (20 ± 2 °C and 60-65% relative humidity (RH)) and during 60 days under cold storage (4 ± 1 °C and 75-80% RH) conditions. Under ambient conditions, a reduction in total phenolic concentrations (TPC) and in total antioxidant activity (TAA) was found for the juice from all tree ages and fruit sizes. Overall, fruit from 18-year-old trees had higher mean TPC (95.86 µg mL(-1) ) and TAA (93.68 mg L(-1) ), as compared to 6 and 35-year-old trees. Likewise, in cold storage, TAA decreased in all fruit size groups from 18 and 35-year-old trees. In all tree age and fruit size groups, TPC decreased initially during 15 days of cold storage and then increased gradually with increase in storage duration. Ascorbic acid concentrations showed an increasing trend in all fruit size groups from 35-year-old trees. Overall, during cold storage, fruit from 18-year-old trees maintained higher mean ascorbic acid (33.05 mg 100 mL(-1) ) concentrations, whereas fruit from 6-year-old trees had higher TAA (153.1 mg L(-1) ) and TPC (115.1 µg mL(-1) ). Large-sized fruit had higher ascorbic acid (32.08 mg 100 mL(-1) ) concentrations and TAA (157.5 mg L(-1) ). Fruit from 18-year-old trees maintained higher TPC and TAA under ambient storage conditions, whereas fruit from 6-year-old trees maintained higher TPC and TAA during cold storage. Small-sized fruit had higher TPC after ambient temperature storage, whereas large fruit size showed higher ascorbic acid concentrations and TAA after cold

The effect of concentration of glycerol and electric current on the morphology and particle size of electrodeposited cadmium powder

Directory of Open Access Journals (Sweden)

S. G. Viswanath

2013-06-01

Full Text Available Cadmium powder was obtained by electrodeposition of cadmium from glycerol and sulphuric acid. The morphology and particle size of these powders were studied. Broken dendrites, intermingled with spongy and irregular particles were observed in the powder. Around 60% of particles were below 100 µm. XRD studies showed that particles with sizes between 212.2 and 303.2 nm were present in the powder. The apparent density of cadmium powder decreased with increase in concentration of glycerol. The stability of the powder and current efficiency were also studied

Achieving secondary prevention low-density lipoprotein particle concentration goals using lipoprotein cholesterol-based data.

Directory of Open Access Journals (Sweden)

Simon C Mathews

Full Text Available BACKGROUND: Epidemiologic studies suggest that LDL particle concentration (LDL-P may remain elevated at guideline recommended LDL cholesterol goals, representing a source of residual risk. We examined the following seven separate lipid parameters in achieving the LDL-P goal of <1000 nmol/L goal for very high risk secondary prevention: total cholesterol to HDL cholesterol ratio, TC/HDL, <3; a composite of ATP-III very high risk targets, LDL-C<70 mg/dL, non-HDL-C<100 mg/dL and TG<150 mg/dL; a composite of standard secondary risk targets, LDL-C<100, non-HDL-C<130, TG<150; LDL phenotype; HDL-C ≥ 40; TG<150; and TG/HDL-C<3. METHODS: We measured ApoB, ApoAI, ultracentrifugation lipoprotein cholesterol and NMR lipoprotein particle concentration in 148 unselected primary and secondary prevention patients. RESULTS: TC/HDL-C<3 effectively discriminated subjects by LDL-P goal (F = 84.1, p<10(-6. The ATP-III very high risk composite target (LDL-C<70, nonHDL-C<100, TG<150 was also effective (F = 42.8, p<10(-5. However, the standard secondary prevention composite (LDL-C<100, non-HDL-C<130, TG<150 was also effective but yielded higher LDL-P than the very high risk composite (F = 42.0, p<10(-5 with upper 95% confidence interval of LDL-P less than 1000 nmol/L. TG<150 and TG/HDL-C<3 cutpoints both significantly discriminated subjects but the LDL-P upper 95% confidence intervals fell above goal of 1000 nmol/L (F = 15.8, p = 0.0001 and F = 9.7, p = 0.002 respectively. LDL density phenotype neared significance (F = 2.85, p = 0.094 and the HDL-C cutpoint of 40 mg/dL did not discriminate (F = 0.53, p = 0.47 alone or add discriminatory power to ATP-III targets. CONCLUSIONS: A simple composite of ATP-III very high risk lipoprotein cholesterol based treatment targets or TC/HDL-C ratio <3 most effectively identified subjects meeting the secondary prevention target level of LDL-P<1000 nmol/L, providing a potential alternative to advanced lipid testing in many clinical

Suspended-sediment concentrations, loads, total suspended solids, turbidity, and particle-size fractions for selected rivers in Minnesota, 2007 through 2011

Science.gov (United States)

Ellison, Christopher A.; Savage, Brett E.; Johnson, Gregory D.

2014-01-01

Sediment-laden rivers and streams pose substantial environmental and economic challenges. Excessive sediment transport in rivers causes problems for flood control, soil conservation, irrigation, aquatic health, and navigation, and transports harmful contaminants like organic chemicals and eutrophication-causing nutrients. In Minnesota, more than 5,800 miles of streams are identified as impaired by the Minnesota Pollution Control Agency (MPCA) due to elevated levels of suspended sediment. The U.S. Geological Survey, in cooperation with the MPCA, established a sediment monitoring network in 2007 and began systematic sampling of suspended-sediment concentrations (SSC), total suspended solids (TSS), and turbidity in rivers across Minnesota to improve the understanding of fluvial sediment transport relations. Suspended-sediment samples collected from 14 sites from 2007 through 2011 indicated that the Zumbro River at Kellogg in the driftless region of southeast Minnesota had the highest mean SSC of 226 milligrams per liter (mg/L) followed by the Minnesota River at Mankato with a mean SSC of 193 mg/L. During the 2011 spring runoff, the single highest SSC of 1,250 mg/L was measured at the Zumbro River. The lowest mean SSC of 21 mg/L was measured at Rice Creek in the northern Minneapolis- St. Paul metropolitan area. Total suspended solids (TSS) have been used as a measure of fluvial sediment by the MPCA since the early 1970s; however, TSS concentrations have been determined to underrepresent the amount of suspended sediment. Because of this, the MPCA was interested in quantifying the differences between SSC and TSS in different parts of the State. Comparisons between concurrently sampled SSC and TSS indicated significant differences at every site, with SSC on average two times larger than TSS concentrations. The largest percent difference between SSC and TSS was measured at the South Branch Buffalo River at Sabin, and the smallest difference was observed at the Des Moines

Release of ultrafine particles from three simulated building processes

International Nuclear Information System (INIS)

Kumar, Prashant; Mulheron, Mike; Som, Claudia

2012-01-01

Building activities are recognised to produce coarse particulate matter but less is known about the release of airborne ultrafine particles (UFPs; those below 100 nm in diameter). For the first time, this study has investigated the release of particles in the 5–560 nm range from three simulated building activities: the crushing of concrete cubes, the demolition of old concrete slabs, and the recycling of concrete debris. A fast response differential mobility spectrometer (Cambustion DMS50) was used to measure particle number concentrations (PNC) and size distributions (PNDs) at a sampling frequency of 10 Hz in a confined laboratory room providing controlled environment and near–steady background PNCs. The sampling point was intentionally kept close to the test samples so that the release of new UFPs during these simulated processes can be quantified. Tri–modal particle size distributions were recorded for all cases, demonstrating different peak diameters in fresh nuclei ( 4 cm −3 . These background modal peaks shifted towards the larger sizes during the work periods (i.e. actual experiments) and the total PNCs increased between 2 and 17 times over the background PNCs for different activities. After adjusting for background concentrations, the net release of PNCs during cube crushing, slab demolition, and ‘dry’ and ‘wet’ recycling events were measured as ∼0.77, 19.1, 22.7 and 1.76 (×10 4 ) cm −3 , respectively. The PNDs were converted into particle mass concentrations (PMCs). While majority of new PNC release was below 100 nm (i.e. UFPs), the bulk of new PMC emissions were constituted by the particles over 100 nm; ∼95, 79, 73 and 90% of total PNCs, and ∼71, 92, 93 and 91% of total PMCs, for cube crushing, slab demolition, dry recycling and wet recycling, respectively. The results of this study firmly elucidate the release of UFPs and raise a need for further detailed studies and designing health and safety related exposure guidelines for

Real-time measurements of suspended sediment concentration and particle size using five techniques

Science.gov (United States)

Felix, D.; Albayrak, I.; Abgottspon, A.; Boes, R. M.

2016-11-01

Fine sediments are important in the design and operation of hydropower plants (HPPs), in particular with respect to sediment management and hydro-abrasive erosion in hydraulic machines. Therefore, there is a need for reliable real-time measurements of suspended sediment mass concentration (SSC) and particle size distribution (PSD). The following instruments for SSC measurements were investigated in a field study during several years at the HPP Fieschertal in the Swiss Alps: (1) turbidimeters, (2) a Laser In-Situ Scattering and Trans- missometry instrument (LISST), (3) a Coriolis Flow and Density Meter (CFDM), (4) acoustic transducers, and (5) pressure sensors. LISST provided PSDs in addition to concentrations. Reference SSCs were obtained by gravimetrical analysis of automatically taken water samples. In contrast to widely used turbidimeters and the single-frequency acoustic method, SSCs obtained from LISST, the CFDM or the pressure sensors were less or not affected by particle size variations. The CFDM and the pressure sensors allowed measuring higher SSC than the optical or the acoustic techniques (without dilution). The CFDM and the pressure sensors were found to be suitable to measure SSC ≥ 2 g/l. In this paper, the measuring techniques, instruments, setup, methods for data treatment, and selected results are presented and discussed.

Arsenic speciation in total contents and bioaccessible fractions in atmospheric particles related to human intakes

International Nuclear Information System (INIS)

Huang, Minjuan; Chen, Xunwen; Zhao, Yinge; Yu Chan, Chuen; Wang, Wei; Wang, Xuemei; Wong, Ming Hung

2014-01-01

Speciation of inorganic trivalent arsenicals (iAs III ), inorganic pentavalent arsenicals (iAs V ), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in total arsenic (As) content and its bioaccessible fractions contained in road dust, household air-conditioning (AC) filter dust and PM 2.5 was investigated. Inorganic As, especially iAs V , was observed as the dominant species. Physiologically based extraction test (PBET), an in-vitro gastrointestinal method, was used to estimate the oral As bioaccessibility in coarse particles and the species present in the oral bioaccessible fraction. A composite lung simulating serum was used to mimic the pulmonary condition to extract the respiratory bioaccessible As and its species in PM 2.5 . Reduction of iAs V to iAs III occurred in both in-vitro gastrointestinal and lung simulating extraction models. The inorganic As species was the exclusive species for absorption through ingestion and inhalation of atmospheric particles, which was an important exposure route to inorganic As, in addition to drinking water and food consumption. - Highlights: • Inorganic As species was the predominant species in dust and airborne particles. • Existence of iAs III in dust and airborne particles increases human health risks. • Reduction from iAs V to iAs III occurred through in-vitro gastrointestinal model. • Reduction from iAs V to iAs III occurred in the simulating pulmonary region. • Atmospheric particles were important exposure sources of inorganic As. - Atmospheric particles are important exposure sources of inorganic As, of which the bioaccessibility is dependent on the extraction phases and models used

Calculation of concentration fields of high-inertia aerosol particles in the flow past a cylindrical fibre

Science.gov (United States)

Zaripov, T. S.; Gilfanov, A. K.; Zaripov, S. K.; Rybdylova, O. D.; Sazhin, S. S.

2018-01-01

The behaviour of high-inertia aerosol particles’ concentration fields in stationary gas suspension flows around a cylinder is investigated using a numerical solution to the Navier-Stokes equations and the fully Lagrangian approach for four Stokes numbers (Stk = 0.1, 1, 4, 10) and three Reynolds numbers (Re = 1, 10, 100). It has been shown that the points of maximum particle concentration along each trajectory shift downstream both when Stk and/or Re increase.

Fluctuations of the number of adsorbed micro/nanoparticles in sensors for measurement of particle concentration in air and liquid environments

Directory of Open Access Journals (Sweden)

Jokić Ivana

2015-01-01

Full Text Available A theoretical model of fluctuations of the number of adsorbed micro/nanoparticles in environmental sensors operating in air and liquids is presented, taking into account the effects of the mass transfer processes of the target particles in a sensor reaction chamber. The expressions for the total power of the corresponding adsorption-desorption noise, and for the corresponding signal-to-noise ratio are also derived. The presented analysis shows that the transfer processes can have a significant influence on the sensors limiting performance. The influence on both the fluctuations spectrum and the signal-to-noise ratio is estimated at different values of target particles concentration, functionalization sites surface density, and adsorption and desorption rate constants (the values are chosen from the ranges corresponding to real conditions. The analysis provides the guidelines for optimization of sensor design and operating conditions for the given target substance and sensor functionalization, in order to decrease the influence of the mass transfer, thus improving the ultimate performance (e.g. minimal detectable signal, signal-to-noise ratio of sensors for particle detection. The calculations we performed show that it is possible to increase the signal-to-noise ratio for as much as two orders of magnitude by using the optimization that eliminates the mass transfer influence. [Projekat Ministarstva nauke Republike Srbije, br. TR32008

Improved sentinel node visualization in breast cancer by optimizing the colloid particle concentration and tracer dosage

NARCIS (Netherlands)

Valdés Olmos, R. A.; Tanis, P. J.; Hoefnagel, C. A.; Nieweg, O. E.; Muller, S. H.; Rutgers, E. J.; Kooi, M. L.; Kroon, B. B.

2001-01-01

Faint lymph uptake may hamper sentinel node (SN) identification by scintigraphy and subsequent gamma probe localization. The aim of the present study was to evaluate an adjustment in the colloid particle concentration and tracer dosage to optimize mammary lymphoscintigraphy. Scintigraphy was

Competition effects in cation binding to humic acid: Conditional affinity spectra for fixed total metal concentration conditions

Science.gov (United States)

David, Calin; Mongin, Sandrine; Rey-Castro, Carlos; Galceran, Josep; Companys, Encarnació; Garcés, José Luis; Salvador, José; Puy, Jaume; Cecilia, Joan; Lodeiro, Pablo; Mas, Francesc

2010-09-01

Information on the Pb and Cd binding to a purified Aldrich humic acid (HA) is obtained from the influence of different fixed total metal concentrations on the acid-base titrations of this ligand. NICA (Non-Ideal Competitive Adsorption) isotherm has been used for a global quantitative description of the binding, which has then been interpreted by plotting the Conditional Affinity Spectra of the H + binding at fixed total metal concentrations (CAScTM). This new physicochemical tool, here introduced, allows the interpretation of binding results in terms of distributions of proton binding energies. A large increase in the acidity of the phenolic sites as the total metal concentration increases, especially in presence of Pb, is revealed from the shift of the CAScTM towards lower affinities. The variance of the CAScTM distribution, which can be used as a direct measure of the heterogeneity, also shows a significant dependence on the total metal concentration. A discussion of the factors that influence the heterogeneity of the HA under the conditions of each experiment is provided, so that the smoothed pattern exhibited by the titration curves can be justified.

Exposure assessment and heart rate variability monitoring in workers handling titanium dioxide particles: a pilot study

Energy Technology Data Exchange (ETDEWEB)

Ichihara, Sahoko [Mie University, Graduate School of Regional Innovation Studies (Japan); Li, Weihua [WHO Collaborating Centre for Research in Human Reproduction, Shanghai Institute of Planned Parenthood Research (China); Omura, Seiichi [Tokyo Institute of Technology (Japan); Fujitani, Yuji [National Institute for Environmental Studies (Japan); Liu, Ying; Wang, Qiangyi [WHO Collaborating Centre for Research in Human Reproduction, Shanghai Institute of Planned Parenthood Research (China); Hiraku, Yusuke [Mie University Graduate School of Medicine, Department of Environmental and Molecular Medicine (Japan); Hisanaga, Naomi [Aichi Gakusen University, Faculty of Human Science and Design (Japan); Wakai, Kenji [Nagoya University Graduate School of Medicine, Department of Preventive Medicine (Japan); Ding, Xuncheng [WHO Collaborating Centre for Research in Human Reproduction, Shanghai Institute of Planned Parenthood Research (China); Kobayashi, Takahiro, E-mail: takakoba@airies.or.jp [Association for International Research Initiatives for Environmental Studies (Japan); Ichihara, Gaku, E-mail: gak@rs.tus.ac.jp [Tokyo University of Science, Department of Occupational and Environmental Health, Faculty of Pharmaceutical Sciences (Japan)

2016-03-15

Titanium dioxide (TiO{sub 2}) particles are used for surface coating and in a variety of products such as inks, fibers, food, and cosmetics. The present study investigated possible respiratory and cardiovascular effects of TiO{sub 2} particles in workers exposed to this particle at high concentration in a factory in China. The diameter of particles collected on filters was measured by scanning electron microscopy. Real-time size-dependent particle number concentration was monitored in the nostrils of four workers using condensation particle counter and optical particle counter. Electrocardiogram was recorded using Holter monitors for the same four workers to record heart rate variability. Sixteen workers underwent assessment of the respiratory and cardiovascular systems. Mass-based individual exposure levels were also measured with personal cascade impactors. The primary particle diameter ranged from 46 to 562 nm. Analysis of covariance of the pooled data of the four workers showed that number of particles with a diameter <300 nm was associated positively with total number of N–N and negatively with total number of increase or decrease in successive RR intervals greater than 50 ms (RR50+/−) or percentage of RR 50+/− that were parameters of parasympathetic function. The total mass concentration was 9.58–30.8 mg/m{sup 3} during work, but significantly less before work (0.36 mg/m{sup 3}). The clear abnormality in respiratory function was not observed in sixteen workers who had worked for 10 months to 13 years in the factory. The study showed that exposure to particles with a diameter <300 nm might affect HRV in workers handling TiO{sub 2} particles. The results highlight the need to investigate the possible impact of exposure to nano-scaled particles on the autonomic nervous system.

Improved soil particle-size analysis by gamma-ray attenuation

International Nuclear Information System (INIS)

Oliveira, J.C.M.; Vaz, C.M.P.; Reichardt, K.; Swartzendruber, D.

1997-01-01

The size distribution of particles is useful for physical characterization of soil. This study was conducted to determine whether a new method of soil particle-size analysis by gamma-ray attenuation could be further improved by changing the depth and time of measurement of the suspended particle concentration during sedimentation. In addition to the advantage of nondestructive, undisturbed measurement by gamma-ray attenuation, as compared with conventional pipette or hydrometer methods, the modifications here suggested and employed do substantially decrease the total time for analysis, and will also facilitate total automation and generalize the method for other sedimentation studies. Experimental results are presented for three different Brazilian soil materials, and illustrate the nature of the fine detail provided in the cumulative particle-size distribution as given by measurements obtained during the relatively short time period of 28 min

Monitoring of event-based mobilization of hydrophobic pollutants in rivers: calibration of turbidity as a proxy for particle facilitated transport in field and laboratory.

Science.gov (United States)

Rügner, Hermann; Schwientek, Marc; Egner, Marius; Grathwohl, Peter

2014-08-15

Transport of many pollutants in rivers is coupled to mobilization of suspended particles which typically occurs during floods. Since the amount of total suspended solids (TSS) in rivers can be monitored by turbidity measurements this may be used as a proxy for the total concentration of particle associated pollutants such as PAHs, PCBs, etc. and several heavy metals. Online turbidity measurements (e.g. by optical backscattering sensors) would then also allow for an assessment of particle and pollutant flux dynamics if once calibrated against TSS and total pollutant concentrations for a given catchment. In this study, distinct flood and thus turbidity events were sampled at high temporal resolution in three contrasting sub-catchments of the River Neckar in Southwest Germany (Ammer, Goldersbach, Steinlach) as well as in the River Neckar itself and investigated for the total amount of PAHs and TSS in water; turbidity (NTU) and grain size distributions of suspended solids were determined as well. Laboratory experiments were performed with natural river bed sediments from different locations (Ammer) to investigate PAH concentrations, TSS and turbidity during sedimentation of suspended particles under controlled conditions (yielding smaller and smaller suspended particles and TSS with time). Laboratory and field results agreed very well and showed that turbidity and TSS were linearly correlated over an extended turbidity range up to 2000 NTU for the field samples and up to 8000 NTU in lab experiments. This also holds for total PAH concentrations which can be reasonably well predicted based on turbidity measurements and TSS vs. PAHs relationships - even for high turbidity values observed during flood events (>2000 NTU). Total PAH concentrations on suspended solids were independent of grain size of suspended particles. This implies that for the rivers investigated the sorption capacity of particles did not change significantly during the observed events. Copyright © 2014

Improved concentration and separation of particles in a 3D dielectrophoretic chip integrating focusing, aligning and trapping

KAUST Repository

Li, Ming; Li, Shunbo; Cao, Wenbin; Li, Weihua; Wen, Weijia; Alici, Gursel

2012-01-01

This article presents a dielectrophoresis (DEP)-based microfluidic device with the three-dimensional (3D) microelectrode configuration for concentrating and separating particles in a continuous throughflow. The 3D electrode structure, where

First long-term study of particle number size distributions and new particle formation events of regional aerosol in the North China Plain

Directory of Open Access Journals (Sweden)

X. J. Shen

2011-02-01

Full Text Available Atmospheric particle number size distributions (size range 0.003–10 μm were measured between March 2008 and August 2009 at Shangdianzi (SDZ, a rural research station in the North China Plain. These measurements were made in an attempt to better characterize the tropospheric background aerosol in Northern China. The mean particle number concentrations of the total particle, as well as the nucleation, Aitken, accumulation and coarse mode were determined to be 1.2 ± 0.9 × 10⁴, 3.6 ± 7.9 × 10³, 4.4 ± 3.4 × 10³, 3.5 ± 2.8 × 10³ and 2 ± 3 cm⁻³, respectively. A general finding was that the particle number concentration was higher during spring compared to the other seasons. The air mass origin had an important effect on the particle number concentration and new particle formation events. Air masses from northwest (i.e. inner Asia favored the new particle formation events, while air masses from southeast showed the highest particle mass concentration. Significant diurnal variations in particle number were observed, which could be linked to new particle formation events, i.e. gas-to-particle conversion. During particle formation events, the number concentration of the nucleation mode rose up to maximum value of 10⁴ cm⁻³. New particle formation events were observed on 36% of the effective measurement days. The formation rate ranged from 0.7 to 72.7 cm⁻³ s⁻¹, with a mean value of 8.0 cm⁻³ s⁻¹. The value of the nucleation mode growth rate was in the range of 0.3–14.5 nm h⁻¹, with a mean value of 4.3 nm h⁻¹. It was an essential observation that on many occasions the nucleation mode was able to grow into the size of cloud condensation nuclei (CCN within a matter of several hours. Furthermore, the new particle formation was regularly followed by a measurable increase in particle mass

Exposure to carbon monoxide, fine particle mass, and ultrafine particle number in Jakarta, Indonesia: effect of commute mode.

Science.gov (United States)

Both, Adam F; Westerdahl, Dane; Fruin, Scott; Haryanto, Budi; Marshall, Julian D

2013-01-15

We measured real-time exposure to PM(2.5), ultrafine PM (particle number) and carbon monoxide (CO) for commuting workers school children, and traffic police, in Jakarta, Indonesia. In total, we measured exposures for 36 individuals covering 93 days. Commuters in private cars experienced mean (st dev) exposures of 22 (9.4) ppm CO, 91 (38) μg/m(3)PM(2.5), and 290 (150)×10(3) particles cm(-3). Mean concentrations were higher in public transport than in private cars for PM(2.5) (difference in means: 22%) and particle counts (54%), but not CO, likely reflecting in-vehicle particle losses in private cars owing to air-conditioning. However, average commute times were longer for private car commuters than public transport commuters (in our sample, 24% longer: 3.0 vs. 2.3 h per day). Commute and traffic-related exposures experienced by Jakarta residents are among the highest in the world, owing to high on-road concentrations and multi-hour commutes. Copyright © 2012 Elsevier B.V. All rights reserved.

Comparison of total protein concentration in skeletal muscle as measured by the Bradford and Lowry assays.

Science.gov (United States)

Seevaratnam, Rajini; Patel, Barkha P; Hamadeh, Mazen J

2009-06-01

The Lowry and Bradford assays are the most commonly used methods of total protein quantification, yet vary in several aspects. To date, no comparisons have been made in skeletal muscle. We compared total protein concentrations of mouse red and white gastrocnemius, reagent stability, protein stability and range of linearity using both assays. The Lowry averaged protein concentrations 15% higher than the Bradford with a moderate correlation (r = 0.36, P = 0.01). However, Bland-Altman analysis revealed considerable bias (15.8 +/- 29.7%). Both Lowry reagents and its protein-reagent interactions were less stable over time than the Bradford. The linear range of concentration was smaller for the Lowry (0.05-0.50 mg/ml) than the Bradford (0-2.0 mg/ml). We conclude that the Bradford and Lowry measures of total protein concentration in skeletal muscle are not interchangeable. The Bradford and Lowry assays have various strengths and weaknesses in terms of substance interference and protein size. However, the Bradford provides greater reagent stability, protein-reagent stability and range of linearity, and requires less time to analyse compared to the Lowry assay.

Low Dose Gamma Irradiation Does Not Affect the Quality or Total Ascorbic Acid Concentration of "Sweetheart" Passionfruit (Passiflora edulis).

Science.gov (United States)

Golding, John B; Blades, Barbara L; Satyan, Shashirekha; Spohr, Lorraine J; Harris, Anne; Jessup, Andrew J; Archer, John R; Davies, Justin B; Banos, Connie

2015-08-26

Passionfruit ( Passiflora edulis , Sims, cultivar "Sweetheart") were subject to gamma irradiation at levels suitable for phytosanitary purposes (0, 150, 400 and 1000 Gy) then stored at 8 °C and assessed for fruit quality and total ascorbic acid concentration after one and fourteen days. Irradiation at any dose (≤1000 Gy) did not affect passionfruit quality (overall fruit quality, colour, firmness, fruit shrivel, stem condition, weight loss, total soluble solids level (TSS), titratable acidity (TA) level, TSS/TA ratio, juice pH and rot development), nor the total ascorbic acid concentration. The length of time in storage affected some fruit quality parameters and total ascorbic acid concentration, with longer storage periods resulting in lower quality fruit and lower total ascorbic acid concentration, irrespective of irradiation. There was no interaction between irradiation treatment and storage time, indicating that irradiation did not influence the effect of storage on passionfruit quality. The results showed that the application of 150, 400 and 1000 Gy gamma irradiation to "Sweetheart" purple passionfruit did not produce any deleterious effects on fruit quality or total ascorbic acid concentration during cold storage, thus supporting the use of low dose irradiation as a phytosanitary treatment against quarantine pests in purple passionfruit.

Nature of Atmospheric Aerosols over the Desert Areas in the Asian Continent: Chemical State and Number Concentration of Particles Measured at Dunhuang, China

International Nuclear Information System (INIS)

Iwasaka, Y.; Shi, G.-Y.; Shen, Z.; Kim, Y. S.; Trochkine, D.; Matsuki, A.; Zhang, D.; Shibata, T.; Nagatani, M.; Nakata, H.

2003-01-01

Measurements of aerosol were made in August and October 2001, and January 2002, at Dunhuang, China (40 o 00'N, 94 o 30'E), to understand the nature of atmospheric particles over the desert areas in the Asian continent. Balloon-borne measurements with an optical particle counter suggested that particle size and concentration had a noticeable peak in size range of super micron in not only the boundary mixing layer but also the free troposphere. Thickness of the boundary mixing layer, from distributions of particle concentration, was about 4 km in summer (17 August 2001), about2.5 km in fall (17 October 2001), and about 3 km in winter (11 January 2002), which suggest active mixing of particles near the boundary in summer. Number-size distribution of particle showed a noticeable peak in the super micron particles size range in the mixing boundary layer: 0.4-2 particles cm -3 at diameter>1.2 μm in summer, 0.05-4 particles cm -3 at diameter >1.2 μm in fall, and 0.1-5 particles cm -3 at diameter>1.2 μm in winter. In winter strong inversion of atmospheric temperature was found in the height range from the boundary to about 3 km and vertical distribution of particle concentration well corresponded with the temperature distribution. Chemical elements of individual aerosols, which were collected in the boundary layer atmosphere at Dunhuang (18 October 2001) were analyzed with an electron microscope equipped with EDX. Those single particle analysis suggested that most of the particles with supermicron size were soil particles, and those particles had little sulfate on its surface. This is a very important different point,comparing with the chemical state of soil particles, which were transported from the desert area of China to Japan, and showed frequently the existence of sulfate on the particle surface. Therefore, it is strongly suggested that dust particles can be chemically modified during their long-range transport from desert areas to Japan

On the role of ice-nucleating aerosol in the formation of ice particles in tropical mesoscale convective systems

Science.gov (United States)

Ladino, Luis A.; Korolev, Alexei; Heckman, Ivan; Wolde, Mengistu; Fridlind, Ann M.; Ackerman, Andrew S.

2018-01-01

Over decades, the cloud physics community has debated the nature and role of aerosol particles in ice initiation. The present study shows that the measured concentration of ice crystals in tropical mesoscale convective systems exceeds the concentration of ice nucleating particles (INPs) by several orders of magnitude. The concentration of INPs was assessed from the measured aerosol particles concentration in the size range of 0.5 to 1 µm. The observations from this study suggest that primary ice crystals formed on INPs make only a minor contribution to the total concentration of ice crystals in tropical mesoscale convective systems. This is found by comparing the predicted INP number concentrations with in-situ ice particle number concentrations. The obtained measurements suggest that ice multiplication is the likely explanation for the observed high concentrations of ice crystals in this type of convective system. PMID:29551842

Concentration-elastic-stress instabilities in the distribution of ions and neutral particles in the insulator layer at the semiconductor surface

International Nuclear Information System (INIS)

Gol'dman, E. I.

2006-01-01

Mobile impurities in the form of ions and neutral associations are present in the insulator films that isolate the semiconductor from the metal electrode. If temperatures and the polarizing electric field are sufficiently high, impurities concentrate at the insulator-semiconductor interface where they exchange electrons with the semiconductor. It is shown that the pairwise interaction of particles via the field of elastic stresses caused by the concentration-related expansion of the insulator can give rise to an instability in the impurity distribution that is uniform over the contact. The stationary small-scale ordering of the particles over the contact of the insulator with the semiconductor arises in the solution of point defects, which is accompanied by annular flows of the particles

An active one-particle microrheometer: incorporating magnetic tweezers to total internal reflection microscopy.

Science.gov (United States)

Gong, Xiangjun; Hua, Li; Wu, Chi; Ngai, To

2013-03-01

We present a novel microrheometer by incorporating magnetic tweezers in the total internal reflection microscopy (TIRM) that enables measuring of viscoelastic properties of materials near solid surface. An evanescent wave generated by a solid∕liquid interface in the TIRM is used as the incident light source in the microrheometer. When a probe particle (of a few micrometers diameter) moves near the interface, it can interact with the evanescent field and reflect its position with respect to the interface by the scattered light intensity. The exponential distance dependence of the evanescent field, on the one hand, makes this technique extremely sensitive to small changes from z-fluctuations of the probe (with a resolution of several nanometers), and on the other, it does not require imaging of the probe with high lateral resolution. Another distinct advantage is the high sensitivity in determining the z position of the probe in the absence of any labeling. The incorporated magnetic tweezers enable us to effectively manipulate the distance of the embedded particle from the interface either by a constant or an oscillatory force. The force ramp is easy to implement through a coil current ramp. In this way, the local viscous and elastic properties of a given system under different confinements can therefore be measured by resolving the near-surface particle motion. To test the feasibility of applying this microrheology to soft materials, we measured the viscoelastic properties of sucrose and poly(ethylene glycol) solutions and compared the results to bulk rheometry. In addition, we applied this technique in monitoring the structure and properties of deformable microgel particles near the flat surface.

COMPARISON OF DIFFERENT EXTRACTION METHODS REPRESENTING AVAILABLE AND TOTAL CONCENTRATIONS OF Cd, Cu, Fe, Mn and Zn IN SOIL

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Vladimir Ivezić

2013-06-01

Full Text Available Various extraction methods are used to predict plant uptake of trace metals. Most commonly it is total concentration that is used for risk assessment and evaluation of trace metal availability. However, recent studies showed that total concentration is a poor indicator of availability while concentrations in soil solution show good correlation with plant uptake. Present study was conducted on magricultural soils with low levels of trace metals where 45 soil samples were collected from different soil types. The main objective was to compare four different extraction methods and examine how total and reactive (EDTA trace metal concentrations correlate ,with soil solution concentration (in this study determined by water extraction. The samples were analyzed by four extraction methods: strong acid extraction (ultra-pure HNO3 extraction and aqua regia, weak acid extraction by EDTA and the most available fraction, fraction in soil solution, were represented by water extraction (weakest extractant. Five elements were investigated (Cd, Cu, Fe, Mn and Zn. Water extraction significantly correlated with EDTA extraction for Cu, Fe and Mn, while total extraction (HNO3 extraction and aqua regia correlated significantly with water extraction only for Cu. No correlation between water extraction and total extraction confirmed poor role of total concentration as an indicator of availability. EDTA extraction can be used to represent reactive pool of trace metals in soil but it should be also taken with caution when using it to describe available fraction.

Elemental concentration analysis in prostate tissues using total reflection X-ray fluorescence

International Nuclear Information System (INIS)

Leitão, R.G.; Palumbo, A.; Souza, P.A.V.R.; Pereira, G.R.; Canellas, C.G.L.; Anjos, M.J.; Nasciutti, L.E.; Lopes, R.T.

2014-01-01

Prostate cancer (PCa) currently represents the second most prevalent malignant neoplasia in men, representing 21% of all cancer cases. Benign Prostate Hyperplasia (BPH) is an illness prevailing in men above the age of 50, close to 90% after the age of 80. The prostate presents a high zinc concentration, about 10-fold higher than any other body tissue. In this work, samples of human prostate tissues with cancer, BPH and normal tissue were analyzed utilizing total reflection X-ray fluorescence spectroscopy using synchrotron radiation technique (SR-TXRF) to investigate the differences in the elemental concentrations in these tissues. SR-TXRF analyses were performed at the X-ray fluorescence beamline at Brazilian National Synchrotron Light Laboratory (LNLS), in Campinas, São Paulo. It was possible to determine the concentrations of the following elements: P, S, K, Ca, Fe, Cu, Zn and Rb. By using Mann–Whitney U test it was observed that almost all elements presented concentrations with significant differences (α=0.05) between the groups studied. - Highlights: ► Prostate cancer is the most frequently diagnosed form of cancer in men. ► Intracellular Zn is correlated with proliferation, differentiation, or apoptosis. ► The prostate gland accumulate high concentration of Zn. ► SR-TXRF is a technique widely used in the analysis of low concentration in samples

Total flavonoid concentrations of bryophytes from Tianmu Mountain, Zhejiang Province (China: Phylogeny and ecological factors.

Directory of Open Access Journals (Sweden)

Xin Wang

Full Text Available The flavonoids in bryophytes may have great significance in phylogeny and metabolism research. However, to date there has been little research on bryophyte metabolites, especially flavonoids. To redress this somewhat, we determined flavonoid concentrations of bryophytes from Tianmu Mountain through a colorimetric assay and considered the factors influencing the results. This is the first time that the flavonoid contents of bryophytes have been examined in detail. The results revealed a range of total flavonoid concentrations in 90 samples collected from Tianmu Mountain from 1.8 to 22.3 mg/g (w/w. The total flavonoid contents of liverworts were generally higher than those of mosses; acrocarpous mosses had generally higher values than that of pleurocarpous mosses. The total flavonoid contents of bryophytes growing at lower light levels were general higher than those growing in full-sun. The total flavonoid contents of epiphytic bryophytes were highest, while those of aquatic bryophytes were the lowest. Total flavonoid contents of species growing at low-latitudes were much higher than those at high-latitude individuals. In conclusion, total flavonoid contents of bryophytes have some connection with plant phylogeny; more flavonoids might be contained in relatively primitive bryophytes. Meanwhile, the effects of ecological factors on total flavonoid contents of bryophytes exist; light and habitat (especially tree habitat and river habitat might be representative factor.

Aging of combustion particles in the atmosphere - results from a field study in Zuerich

International Nuclear Information System (INIS)

Burtscher, H.; Leonardi, A.; Steiner, D.; Baltensperger, U.; Weber, A.

1993-01-01

At different locations in Zurich (urban and suburban area) ambient aerosol has been measured by a variety of methods. Total mass concentration, black carbon mass concentration, size distribution, Fuchs surface and photoelectric charging of particles (as a measure for the PAH concentration) have been determined. As a reference for 'fresh' aerosol, measurements have also been carried out in a car parking garage. By comparing the data obtained at different locations and different times of the day aging processes can be investigated. All measured signals show significant peaks during the rush-hours, indicating that the majority of the particles arise from automotive traffic. Aging is expressed by decreasing number concentrations, increasing diameter (coagulation) and decreasing black carbon and PAH content of the particles. The decrease in PAH and black carbon fraction may be due to mixing of the aerosol with non-combustion particles or by condensation of material from the gas phase on the particle; the decrease in PAH concentration may also be due to degradation of the PAHs. 11 refs., 6 figs

Long-term observation of water-soluble chemical components and acid-digested metals in the total suspended particles collected at Okinawa, Japan

Science.gov (United States)

Handa, D.; Okada, K.; Kuroki, Y.; Nakama, Y.; Nakajima, H.; Somada, Y.; Ijyu, M.; Azechi, S.; Oshiro, Y.; Nakaema, F.; Miyagi, Y.; Arakaki, T.; Tanahara, A.

2011-12-01

The economic growth and population increase in recent Asia have been increasing air pollution. Emission rate of air pollutants from Asia, in particular oxides of nitrogen, surpassed those from North America and Europe and should continue to exceed them for decades. Okinawa Island is situated approximately 1500 km south of Tokyo, Japan, 2000 km southeast of Beijing, China, and 1000 km south of South Korea. Its location is ideal in observing East Asia's air quality because maritime air mass prevails during summer, while continental air mass dominates during fall, winter, and spring. The maritime air mass data can be seen as background clean air and can be compared with continental air masses which have been affected by anthropogenic activities. We collected total suspended particles (TSP) on quartz filters by using a high volume air sampler at the Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS), Okinawa, Japan during August 2005 and August 2010. Sampling duration was one week for each sample. We determined the concentrations of water-soluble anions, cations, water-soluble organic carbon (WSOC) and acid-digested metals in TSP samples using ion chromatography, atomic absorption spectrometry, total organic carbon analyzer and Inductively Coupled Plasma Mass spectrometry (ICP-MS), respectively. Seasonal variation of water-soluble chemical components and acid-digested metals showed that the concentrations were the lowest in summer, higher in fall and winter, and the highest in spring. When air mass came from Asian continent, the concentrations of water-soluble chemical components and acid-digested metals were much higher compared to the other directions, suggesting long-range transport of air pollutants from Asian continent. Also, when the air mass came from Asian continent (75-100% dominant), the mean concentrations of non-sea salt sulfate and nitrate increased ca. 1.8 times and ca. 3.7 times, respectively between 2005 and 2010, and the ratio of nitrate to

Characteristics of particle-bound polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in atmosphere used in carbon black feeding process at a tire manufacturing plant.

Science.gov (United States)

Chuang, Kuen-Yuan; Lai, Chia-Hsiang; Peng, Yen-Ping; Yen, Ting-Yu

2015-12-01

Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were estimated for different particle size distributions in a carbon black feeding process at a tire manufacturing plant on 15 days in March and April of 2014. A total of 75 integrated air samples were collected using a micro-orifice uniform deposition impactor (MOUDI). Particle-bound PCDD/Fs were analyzed using a high-resolution gas chromatograph/high-resolution mass spectrometer (HRGC/HRMS). Concentrations of thoracic particles and total particles produced in the carbon black feeding process of a tire manufacturing plant were measured in ranges of 0.19-2.61 and 0.28-4.22 mg/m(3), respectively. On all sampling days, the three most abundant species of PCDD/Fs were OCDD, 1,2,3,4,6,7,8-HpCDF, and OCDF. The mean concentrations of total PCDD/Fs were 0.74-6.83 pg/m(3) within five particle size ranges. Total I-TEQ in particulate matter (PM)18 and PM2.5-10, respectively. However, the total I-TEQ of thoracic PM contributed approximately 74 % of the total I-TEQ of total PM. The assessment of health risk indicates that exposure to fractions of thoracic PM by inhalation poses a significant cancer risk (>10(-6)).

Factors influencing concentrations of dissolved gaseous mercury (DGM) and total mercury (TM) in an artificial reservoir

International Nuclear Information System (INIS)

Ahn, Myung-Chan; Kim, Bomchul; Holsen, Thomas M.; Yi, Seung-Muk; Han, Young-Ji

2010-01-01

The effects of various factors including turbidity, pH, DOC, temperature, and solar radiation on the concentrations of total mercury (TM) and dissolved gaseous mercury (DGM) were investigated in an artificial reservoir in Korea. Episodic total mercury accumulation events occurred during the rainy season as turbidity increased, indicating that the TM concentration was not controlled by direct atmospheric deposition. The DGM concentration in surface water ranged from 3.6 to 160 pg/L, having a maximum in summer and minimum in winter. While in most previous studies DGM was controlled primarily by a photo-reduction process, DGM concentrations tracked the amount of solar radiation only in winter when the water temperature was fairly low in this study. During the other seasons microbial transformation seemed to play an important role in reducing Hg(II) to Hg(0). DGM increased as dissolved organic carbon (DOC) concentration increased (p-value < 0.01) while it increased with a decrease of pH (p-value < 0.01). - Long-term in-situ monitoring of TM and DGM concentrations with various factors was executed in a large artificial reservoir in this study.

Method to determine the activity concentration and total activity of radioactive waste

International Nuclear Information System (INIS)

Angeles C, A.

2001-02-01

A characteristic system of radioactive waste is described to determine the concentration of radionuclides activity and the total activity of bundles of radioactive waste. The system this integrated by three subsystems: - Elevator of drums. - Electromechanics. - Gamma spectroscopy. In the system it is analyzed waste of issuing gamma specifically, and this designed for materials of relative low density and it analyzes materials of cylindrical recipients

Physical and chemical characteristics including total and geochemical forms of phosphorus in sediment from the top 30 centimeters of cores collected in October 2006 at 26 sites in Upper Klamath Lake, Oregon

Science.gov (United States)

Simon, Nancy S.; Ingle, Sarah N.

2011-01-01

μThis study of phosphorus (P) cycling in eutrophic Upper Klamath Lake (UKL), Oregon, was conducted by the U.S. Geological Survey in cooperation with the U.S. Bureau of Reclamation. Lakebed sediments from the upper 30 centimeters (cm) of cores collected from 26 sites were characterized. Cores were sampled at 0.5, 1.5, 2.5, 3.5, 4.5, 10, 15, 20, 25, and 30 cm. Prior to freezing, water content and sediment pH were determined. After being freeze-dried, all samples were separated into greater than 63-micron (μm) particle-size (coarse) and less than 63-μm particle-size (fine) fractions. In the surface samples (0.5 to 4.5 cm below the sediment water interface), approximately three-fourths of the particles were larger than 63-μm. The ratios of the coarse particle-size fraction (>63 μm) and the fine particle-size fraction (determination of total concentrations of aluminum (Al), calcium (Ca), carbon (C), iron (Fe), poorly crystalline Fe, nitrogen (N), P, and titanium (Ti). Total Fe concentrations were the largest in sediment from the northern portion of UKL, Howard Bay, and the southern portion of the lake. Concentrations of total Al, Ca, and Ti were largest in sediment from the northern, central, and southernmost portions of the lake and in sediment from Howard Bay. Concentrations of total C and N were largest in sediment from the embayments and in sediment from the northern arm and southern portion of the lake in the general region of Buck Island. Concentrations of total C were larger in the greater than 63-μm particle-size fraction than in the less than 63-μm particle-size fraction. Sediments were sequentially extracted to determine concentrations of inorganic forms of P, including loosely sorbed P, P associated with poorly crystalline Fe oxides, and P associated with mineral phases. The difference between the concentration of total P and sum of the concentrations of inorganic forms of P is referred to as residual P. Residual P was the largest fraction of P in all

The effect of a concentration-dependent viscosity on particle transport in a channel flow with porous walls

KAUST Repository

Herterich, James G.; Griffiths, Ian M.; Vella, Dominic; Field, Robert W.

2014-01-01

The transport of a dilute suspension of particles through a channel with porous walls, accounting for the concentration dependence of the viscosity, is analyzed. In particular, we study two cases of fluid permeation through the porous channel walls

Correlation of the concentration of the carbon-associated radiation damage levels with the total carbon concentration in silicon

Energy Technology Data Exchange (ETDEWEB)

Ferenczi, G.; Londos, C.A.; Pavelka, T.; Somogyi, M.; Mertens, A.

1988-01-01

The dominant carbon-related radiation damage center in silicon was studied in detail by deep level transient spectroscopy. Samples with different carbon and oxygen content were implanted with gradually increasing proton fluence. Two energetically closely spaced levels were revealed and tentative identities were assigned. One at E/sub T/+E/sub V/ = 0.344 eV (sigma/sub p/ = 1.1 x 10/sup -16/ cm/sup 2/) is assigned as the C+O/sub i/ complex, and that at E/sub T/+E/sub V/ = 0.370 eV (sigma/sub p/ = 8 x 10/sup -18/ cm/sup 2/) is assigned as the C/sub s/-Si/sub i/-C/sub s/ complex. It was shown that the concentration of these defects is correlated to the total concentration of carbon in the crystal.

HPLC for simultaneous quantification of total ceramide, glucosylceramide, and ceramide trihexoside concentrations in plasma

NARCIS (Netherlands)

Groener, Johanna E. M.; Poorthuis, Ben J. H. M.; Kuiper, Sijmen; Helmond, Mariette T. J.; Hollak, Carla E. M.; Aerts, Johannes M. F. G.

2007-01-01

BACKGROUND: Simple, reproducible assays are needed for the quantification of sphingolipids, ceramide (Cer), and sphingoid bases. We developed an HPLC method for simultaneous quantification of total plasma concentrations of Cer, glucosylceramide (GlcCer), and ceramide trihexoside (CTH). METHODS:

Fast Multispectral Radiometry for Particles Analysis

International Nuclear Information System (INIS)

Sharon, A.; Halevy, I.; Sattinger, D.; Yaar, I.; Krantz, L.; Pinhas, M.

2014-01-01

The radiological risk following detonation of radiological dispersal device (RDD) is highly depends the final particles’ size distribution remains after the detonation. In order to produce a realistic source term for the atmospheric dispersion model we should be able to predict the total fraction of aerosols created after the detonation as well as the respirable part of this fraction. The rest of the particles will not be dispersed downwind and hence them concentration will be calculated using much simpler models. The radiological risk out of radioactive (RA) material is highly depends on the particle size. Respirable size (<10 microns) of Alfa, Beta and Gamma emitters are all dangerous when inhaled into the body while larger aerosolos might be risky from a distance (Gamma emitters) or in an external body contact (Alfa, Beta and Gamma). Larger particles (which are not aerosols) are dangerous as fragments when penetrating the body (Alfa, Beta and Gamma) or when depositing on the ground as Gamma emitters. We show here that by using a fast multispectral radiometryfor the detonation fireball analysis it is possible to quantify the reduction of total amount of aerosols due to particles agglomeration with dirt

Distribution of gaseous and particle-bound Hg concentrations at the sites representative for urban and non-urban zones of Silesia Province

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Pyta Halina

2018-01-01

Full Text Available The basic features of the distribution of total gaseous (TGM and particle-bound mercury (PBM concentrations were determined for a five locations representative for urban (Bielsko-Biała, Lubliniec, Zabrze and rural areas (Godów, Złoty Potok of Silesia Province. Gaseous mercury concentrations were measured (1 continuously - the automatic 1h TGM measurements in Zloty Potok and Zabrze and (2 non-continuously manual 24h TGM measurements with a pre-concentration of the Hg on gold traps (Bielsko-Biała, Lubliniec, Godów. The PBM concentrations were measured non-continuously by taking PM2.5 samples. The Hg content was determined by using a CVAAS method. The highest average concentration of TGM was recorded in Zabrze (2.8ng/m3, significantly lower (2.0ng/m3 in Bielsko-Biała and in the non-urban station in Godów, the lowest concentration (<2.0 ng/m3 was observed in Lubliniec and at the regional background station in Zloty Potok. The results obtained for TGM concentrations exceeded the European average level of 1.5 ng/m3 (AirBase, 2014. The highest average PBM concentration, associated with PM2.5, was obtained in Zabrze (70pg/m3, more than 20% lower results were obtained in Bielsko-Biała and Godów, finally, the lowest one (lower by about 40% in comparison with Zabrze were obtained in Lubliniec and Złoty Potok. Moreover, an enrichment of Hg concentration in PM was observed with the increasing of the PM content, during the heating season.

Laser ablation-laser induced breakdown spectroscopy for the measurement of total elemental concentration in soils.

Science.gov (United States)

Pareja, Jhon; López, Sebastian; Jaramillo, Daniel; Hahn, David W; Molina, Alejandro

2013-04-10

The performances of traditional laser-induced breakdown spectroscopy (LIBS) and laser ablation-LIBS (LA-LIBS) were compared by quantifying the total elemental concentration of potassium in highly heterogeneous solid samples, namely soils. Calibration curves for a set of fifteen samples with a wide range of potassium concentrations were generated. The LA-LIBS approach produced a superior linear response different than the traditional LIBS scheme. The analytical response of LA-LIBS was tested with a large set of different soil samples for the quantification of the total concentration of Fe, Mn, Mg, Ca, Na, and K. Results showed an acceptable linear response for Ca, Fe, Mg, and K while poor signal responses were found for Na and Mn. Signs of remaining matrix effects for the LA-LIBS approach in the case of soil analysis were found and discussed. Finally, some improvements and possibilities for future studies toward quantitative soil analysis with the LA-LIBS technique are suggested.

Number and mass analysis of particles emitted by aircraft engine

Directory of Open Access Journals (Sweden)

Jasiński Remigiusz

2017-01-01

Full Text Available Exhaust emissions from aircraft is a complex issue because of the limited possibility of measurements in flight conditions. Most of the studies on this subject were performed on the basis of stationary test. Engine certification data is used to calculate total emissions generated by air transport. However, it doesnt provide any information about the local effects of air traffic. The main threat to local communities is particulate matter emissions, which adversely affects human health. Emissions from air transport affect air quality, particularly in the vicinity of the airports; it also contributes to the greenhouse effect. The article presents the measurement results of the concentration and size distribution of particles emitted during aircraft landing operation. Measurements were carried out during the landings of aircraft at a civilian airport. It was found that a single landing operation causes particle number concentration value increase of several ten-fold in a short period of time. Using aircraft engine certification data, the methodology for determination of the total number of particles emitted during a single landing operation was introduced.

Experimental investigation of particle emissions under different EGR ratios on a diesel engine fueled by blends of diesel/gasoline/n-butanol

International Nuclear Information System (INIS)

Huang, Haozhong; Liu, Qingsheng; Wang, Qingxin; Zhou, Chengzhong; Mo, Chunlan; Wang, Xueqiang

2016-01-01

Highlights: • The effects of EGR and blend fuels on particulate emission were studied in CI engine. • EGR ⩽ 20%, gasoline or n-butanol increases total particulate number concentration. • EGR ⩾ 30%, gasoline or n-butanol reduces total particulate number concentration. • As EGR ratio increased, the particulate mass concentrations of four fuels increased. • Gasoline or n-butanol increases the ratio of sub-25 nm particles number concentration. - Abstract: The particle emission characteristics of a high-pressure common-rail engine under different EGR conditions were investigated, using pure diesel (D100), diesel/gasoline (with a volume ratio of 70:30, D70G30), diesel/n-butanol (with a volume ratio of 70:30, D70B30) and diesel/gasoline/n-butanol (with a volume ratio of 70:15:15, D70G15B15) for combustion. Our results show that, with increasing EGR ratios, the in-cylinder pressure peak decreases and the heat release is delayed for the combustion of each fuel. At an EGR ratio of 30%, the combustion pressure peaks of D70G30, D70B30, D70G15B15 and D100 have similar values; with an EGR ratio of 40%, the combustion pressure peaks and release rate peaks of D70G30 and D70G15B15 are both lower with respect to D100. For small and medium EGR ratios (⩽20%), after the addition of gasoline and/or n-butanol to the fuel, the total particle number concentration (TPNC) increases, while both the soot emissions and the average geometric size of particles decrease. At large EGR ratios (30% and 40%), the TPNC of D70B30, D70G15B15 and D70G20 compared to D100 are reduced by a maximum amount of 74.7%, 66.7% and 28.6%, respectively. As the EGR ratio increases, the total particle mass concentration increases gradually for all four fuels. Blending gasoline or/and n-butanol into diesel induces an increase in the number concentration of sub-25 nm particles (PN25) which may be harmful in terms of health. However, the PN25 decreases with increasing the EGR ratio for all the tested fuels

Polyaspartic Acid Concentration Controls the Rate of Calcium Phosphate Nanorod Formation in High Concentration Systems

Energy Technology Data Exchange (ETDEWEB)

Krogstad, Daniel V. [Biosystems and; Wang, Dongbo [Biosystems and; Lin-Gibson, Sheng [Biosystems and

2017-08-31

Polyelectrolytes are known to greatly affect calcium phosphate (CaP) mineralization. The reaction kinetics as well as the CaP phase, morphology and aggregation state depend on the relative concentrations of the polyelectrolyte and the inorganic ions in a complex, nonlinear manner. This study examines the structural evolution and kinetics of polyaspartic acid (pAsp) directed CaP mineralization at high concentrations of polyelectrolytes, calcium, and total phosphate (19–30 mg/mL pAsp, 50–100 mM Ca2+, Ca/P = 2). Using a novel combination of characterization techniques including cryogenic transmission electron microscopy (cryo-TEM), spectrophotometry, X-ray total scattering pair distribution function analysis, and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), it was determined that the CaP mineralization occurred over four transition steps. The steps include the formation of aggregates of pAsp stabilized CaP spherical nanoparticles (sNP), crystallization of sNP, oriented attachment of the sNP into nanorods, and further crystallization of the nanorods. The intermediate aggregate sizes and the reaction kinetics were found to be highly polymer concentration dependent while the sizes of the particles were not concentration dependent. This study demonstrates the complex role of pAsp in controlling the mechanism as well as the kinetics of CaP mineralization.

EFFECTS OF COMMONLY USED COOKING PRACTICES ON TOTAL MERCURY CONCENTRATION IN FISH AND THEIR IMPACT ON EXPOSURE ASSESSMENTS

Science.gov (United States)

The effects of cooking practices commonly used by Native Americans on total mercury concentrations in fish were investigated. A preparation factor relating mercury concentrations in fish as prepared for consumption to mercury concentration data as measured in typical environmenta...

Total antioxidative capacity and zinc concentration in dogs suffering from perianal tumours

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Brodzki Adam

2015-09-01

Full Text Available The aim of the study was to determine total antioxidative capacity (TAC and zinc concentration in serum of dogs suffering from perianal tumours just before the start of the antihormonal treatment (AHT and one and six months later. The study was performed on 45 dogs divided into two groups: control group suffering from non-malignant tumours (N = 24 and a group with malignant neoplastic changes (N = 21. Serum TAC and zinc concentrations were measured using photometric and atomic absorption spectrophotometric methods. Six months after the start of the AHT, TAC was significantly lower by 10.6% in dogs with malignant tumours when compared to controls (P = 0.03. In the non-malignant group, serum zinc concentration was higher before the treatment than in the malignant group, while the opposite results were observed six months later (P < 0.001. In the non-malignant group, gradually decreasing values of serum zinc concentration at each stage of the investigation were observed, while the opposite results were obtained in the malignant group (P < 0.05. The obtained results indicate that malignant neoplastic process is associated with significantly reduced TAC. Determination of serum zinc concentration in dogs with non-malignant and malignant perianal tumours may have practical diagnostic and prognostic values and may serve towards increasing the effectiveness of AHT monitoring.

CONSISTENT INFLAMMATORY RESPONSE FOLLOWING EXPOSURE TO CONCENTRATED AMBIENT PARTICLES (CAPS) DURING FALL SEASON IN WISTAR-KYOTO RATS

Science.gov (United States)

CONSISTENT INFLAMMATORY RESPONSE FOLLOWING EXPOSURE TO CONCENTRATED AMBIENT PARTICLES (CAPs) DURING FALL SEASON IN WISTAR-KYOTO RATS.UP Kodavanti, MC Schladweiler, AD Ledbetter, LC Walsh, PS Gilmour, MI Gilmour, WP Watkinson, JP Nolan, JH Richards, D Andrews, DL Costa. US EPA...

Investigation of the evolution of atmospheric particles with integration of the stochastic particle-resolved model partmc-mosaic and atmospheric measurements

Science.gov (United States)

Tian, Jian

With the recently-developed particle-resolved model PartMC-MOSAIC, the mixing state and other physico-chemical properties of individual aerosol particles can be tracked as the particles undergo aerosol aging processes. However, existing PartMC-MOSAIC applications have mainly been based on idealized scenarios, and a link to real atmospheric measurement has not yet been established. In this thesis, we extend the capability of PartMC-MOSAIC and apply the model framework to three distinct scenarios with different environmental conditions to investigate the physical and chemical aging of aerosols in those environments. The first study is to investigate the evolution of particle mixing state and cloud condensation nuclei (CCN) activation properties in a ship plume. Comparisons of our results with observations from the QUANTIFY Study in 2007 in the English channel and the Gulf of Biscay showed that the model was able to reproduce the observed evolution of total number concentration and the vanishing of the nucleation mode consisting of sulfate particles. Further process analysis revealed that during the first hour after emission, dilution reduced the total number concentration by four orders of magnitude, while coagulation reduced it by an additional order of magnitude. Neglecting coagulation resulted in an overprediction of more than one order of magnitude in the number concentration of particles smaller than 40 nm at a plume age of 100 s. Coagulation also significantly altered the mixing state of the particles, leading to a continuum of internal mixtures of sulfate and black carbon. The impact of condensation on CCN concentrations depended on the supersaturation threshold at which CCN activity was evaluated. Nucleation was observed to have a limited impact on the CCN concentration in the ship plume we studied, but was sensitive to formation rates of secondary aerosol. For the second study we adapted PartMC to represent the aerosol evolution in an aerosol chamber, with

Live Imaging of Cellular Internalization of Single Colloidal Particle by Combined Label-Free and Fluorescence Total Internal Reflection Microscopy.

Science.gov (United States)

Byrne, Gerard D; Vllasaliu, Driton; Falcone, Franco H; Somekh, Michael G; Stolnik, Snjezana

2015-11-02

In this work we utilize the combination of label-free total internal reflection microscopy and total internal reflectance fluorescence (TIRM/TIRF) microscopy to achieve a simultaneous, live imaging of single, label-free colloidal particle endocytosis by individual cells. The TIRM arm of the microscope enables label free imaging of the colloid and cell membrane features, while the TIRF arm images the dynamics of fluorescent-labeled clathrin (protein involved in endocytosis via clathrin pathway), expressed in transfected 3T3 fibroblasts cells. Using a model polymeric colloid and cells with a fluorescently tagged clathrin endocytosis pathway, we demonstrate that wide field TIRM/TIRF coimaging enables live visualization of the process of colloidal particle interaction with the labeled cell structure, which is valuable for discerning the membrane events and route of colloid internalization by the cell. We further show that 500 nm in diameter model polystyrene colloid associates with clathrin, prior to and during its cellular internalization. This association is not apparent with larger, 1 μm in diameter colloids, indicating an upper particle size limit for clathrin-mediated endocytosis.

The influences of ambient particle composition and size on particle infiltration in Los Angeles, CA, residences.

Science.gov (United States)

Sarnat, Stefanie Ebelt; Coull, Brent A; Ruiz, Pablo A; Koutrakis, Petros; Suh, Helen H

2006-02-01

Particle infiltration is a key determinant of the indoor concentrations of ambient particles. Few studies have examined the influence of particle composition on infiltration, particularly in areas with high concentrations of volatile particles, such as ammonium nitrate (NH4NO3). A comprehensive indoor monitoring study was conducted in 17 Los Angeles-area homes. As part of this study, indoor/outdoor concentration ratios during overnight (nonindoor source) periods were used to estimate the fraction of ambient particles remaining airborne indoors, or the particle infiltration factor (FINF), for fine particles (PM2.5), its nonvolatile (i.e., black carbon [BC]) and volatile (i.e., nitrate [NO3-]) components, and particle sizes ranging between 0.02 and 10 microm. FINF was highest for BC (median = 0.84) and lowest for NO3- (median = 0.18). The low FINF for NO3- was likely because of volatilization of NO3- particles once indoors, in addition to depositional losses upon building entry. The FINF for PM2.5 (median = 0.48) fell between those for BC and NO3-, reflecting the contributions of both particle components to PM25. FINF varied with particle size, air-exchange rate, and outdoor NO3- concentrations. The FINF for particles between 0.7 and 2 microm in size was considerably lower during periods of high as compared with low outdoor NO3- concentrations, suggesting that outdoor NO3- particles were of this size. This study demonstrates that infiltration of PM2.5 varies by particle component and is lowest for volatile species, such as NH4NO3. Our results suggest that volatile particle components may influence the ability for outdoor PM concentrations to represent indoor and, thus, personal exposures to particles of ambient origin, because volatilization of these particles causes the composition of PM2.5 to differ indoors and outdoors. Consequently, particle composition likely influences observed epidemiologic relationships based on outdoor PM concentrations, especially in areas

On the dependence of quasipotential on the total energy of a two-particle system

International Nuclear Information System (INIS)

Kapshaj, V.N.; Savrin, V.I.

1986-01-01

For a system of two relativistic particles described in the framework of the Logunov-Tavkhelidze one-time approach the dependence is calculated of the one-boson exchange potential on the total energy of the system. It is shown that in spite of a nonlocal form of the quasipotential obtained, three-dimensional equations for the wave function are reduced to one-dimensional ones by means of partial expansion. Influence of the energy dependence of the quasipotential on its behaviour in the coordinate representation is discussed

Concentration of total proteins in blood plasma of chickens hatched from irradiated eggs with low dose gamma radiation

International Nuclear Information System (INIS)

Vilic, M.; Kraljevic, P.; Miljanic, S.; Simpraga, M.

2005-01-01

It is known that low-dose ionising radiation may have stimulating effects on chickens. Low doses may also cause changes in the concentration of blood plasma total proteins, glucose and cholesterol in chickens. This study investigates the effects of low dose gamma-radiation on the concentration of total proteins in the blood plasma of chickens hatched from eggs irradiated with a dose of 0.15 Gy on incubation days 7 and 19. Results were compared with the control group (chickens hatched from non-irradiated eggs). After hatching, all other conditions were the same for both groups. Blood samples were drawn from the heart, and later from the wing vein on days 1, 3, 5, 7,10, 20, 30 and 42. The concentration of total proteins was determined spectrophotometrically using Boehringer Mannheim GmbH optimised kits. The concentration of total proteins in blood plasma in chickens hatched from eggs irradiated with 0.15 Gy on incubation day 7 showed a statistically significant decrease on the sampling day 3 (P less than 0.05) and 7 (P less than 0.01). The concentration of total proteins in blood plasma in chickens hatched from eggs irradiated with 0.15 Gy on incubation day 19 showed a statistically significant increase only on sampling day 1 (P less than 0.05). These results suggest that exposure of eggs to 0.15 Gy of gamma-radiation on the 7th and 19th day of incubation could produce different effects on the protein metabolism in chickens.(author)

A nonlocal species concentration theory for diffusion and phase changes in electrode particles of lithium ion batteries

Science.gov (United States)

Zhang, Tao; Kamlah, Marc

2018-01-01

A nonlocal species concentration theory for diffusion and phase changes is introduced from a nonlocal free energy density. It can be applied, say, to electrode materials of lithium ion batteries. This theory incorporates two second-order partial differential equations involving second-order spatial derivatives of species concentration and an additional variable called nonlocal species concentration. Nonlocal species concentration theory can be interpreted as an extension of the Cahn-Hilliard theory. In principle, nonlocal effects beyond an infinitesimal neighborhood are taken into account. In this theory, the nonlocal free energy density is split into the penalty energy density and the variance energy density. The thickness of the interface between two phases in phase segregated states of a material is controlled by a normalized penalty energy coefficient and a characteristic interface length scale. We implemented the theory in COMSOL Multiphysics^{circledR } for a spherically symmetric boundary value problem of lithium insertion into a Li_xMn_2O_4 cathode material particle of a lithium ion battery. The two above-mentioned material parameters controlling the interface are determined for Li_xMn_2O_4 , and the interface evolution is studied. Comparison to the Cahn-Hilliard theory shows that nonlocal species concentration theory is superior when simulating problems where the dimensions of the microstructure such as phase boundaries are of the same order of magnitude as the problem size. This is typically the case in nanosized particles of phase-separating electrode materials. For example, the nonlocality of nonlocal species concentration theory turns out to make the interface of the local concentration field thinner than in Cahn-Hilliard theory.

Isoprene in poplar emissions: effects on new particle formation and OH concentrations

Science.gov (United States)

Kiendler-Scharr, A.; Andres, S.; Bachner, M.; Behnke, K.; Broch, S.; Hofzumahaus, A.; Holland, F.; Kleist, E.; Mentel, T. F.; Rubach, F.; Springer, M.; Steitz, B.; Tillmann, R.; Wahner, A.; Schnitzler, J.-P.; Wildt, J.

2012-01-01

Stress-induced volatile organic compound (VOC) emissions from transgenic Grey poplar modified in isoprene emission potential were used for the investigation of photochemical secondary organic aerosol (SOA) formation. In poplar, acute ozone stress induces the emission of a wide array of VOCs dominated by sesquiterpenes and aromatic VOCs. Constitutive light-dependent emission of isoprene ranged between 66 nmol m-2 s-1 in non-transgenic controls (wild type WT) and nearly zero (plants (line RA22), respectively. Nucleation rates of up to 3600 cm-3 s-1 were observed in our experiments. In the presence of isoprene new particle formation was suppressed compared to non-isoprene containing VOC mixtures. Compared to isoprene/monoterpene systems emitted from other plants the suppression of nucleation by isoprene was less effective for the VOC mixture emitted from stressed poplar. This is explained by the observed high efficiency of new particle formation for emissions from stressed poplar. Direct measurements of OH in the reaction chamber revealed that the steady state concentration of OH is lower in the presence of isoprene than in the absence of isoprene, supporting the hypothesis that isoprenes' suppressing effect on nucleation is related to radical chemistry. In order to test whether isoprene contributes to SOA mass formation, fully deuterated isoprene (C5D8) was added to the stress-induced emission profile of an isoprene free poplar mutant. Mass spectral analysis showed that, despite the isoprene-induced suppression of particle formation, fractions of deuterated isoprene were incorporated into the SOA. A fractional mass yield of 2.3% of isoprene was observed. Future emission changes due to land use and climate change may therefore affect both gas phase oxidation capacity and new particle number formation.

Distribution of polyethylene wear debris and bone particles in granuloma tissue around total hip joint replacements

Czech Academy of Sciences Publication Activity Database

Zolotarevova, E.; Lapčíková, Monika; Šlouf, Miroslav; Entlicher, G.; Pokorný, D.; Veselý, F.; Sosna, A.

2008-01-01

Roč. 18, č. 2 (2008), s. 173-174 ISSN 1120-7000. [Domestic Meeting of the European Hip Society /8./. 11.06.2008-13.06.2008, Madrid] R&D Projects: GA MŠk 2B06096 Institutional research plan: CEZ:AV0Z40500505 Keywords : wear debris * bone particles * total hip joint replacement Subject RIV: CD - Macromolecular Chemistry www. hip -int.com

Brownian coagulation at high particle concentrations

NARCIS (Netherlands)

Trzeciak, T.M.

2012-01-01

The process of Brownian coagulation, whereby particles are brought together by thermal motion and grow by collisions, is one of the most fundamental processes influencing the final properties of particulate matter in a variety of technically important systems. It is of importance in colloids,

Sub-micron particle number size distribution characteristics at two urban locations in Leicester

Science.gov (United States)

Hama, Sarkawt M. L.; Cordell, Rebecca L.; Kos, Gerard P. A.; Weijers, E. P.; Monks, Paul S.

2017-09-01

The particle number size distribution (PNSD) of atmospheric particles not only provides information about sources and atmospheric processing of particles, but also plays an important role in determining regional lung dose. Owing to the importance of PNSD in understanding particulate pollution two short-term campaigns (March-June 2014) measurements of sub-micron PNSD were conducted at two urban background locations in Leicester, UK. At the first site, Leicester Automatic Urban Rural Network (AURN), the mean number concentrations of nucleation, Aitken, accumulation modes, the total particles, equivalent black carbon (eBC) mass concentrations were 2002, 3258, 1576, 6837 # cm-3, 1.7 μg m-3, respectively, and at the second site, Brookfield (BF), were 1455, 2407, 874, 4737 # cm-3, 0.77 μg m-3, respectively. The total particle number was dominated by the nucleation and Aitken modes, with both consisting of 77%, and 81% of total number concentrations at AURN and BF sites, respectively. This behaviour could be attributed to primary emissions (traffic) of ultrafine particles and the temporal evolution of mixing layer. The size distribution at the AURN site shows bimodal distribution at 22 nm with a minor peak at 70 nm. The size distribution at BF site, however, exhibits unimodal distribution at 35 nm. This study has for the first time investigated the effect of Easter holiday on PNSD in UK. The temporal variation of PNSD demonstrated a good degree of correlation with traffic-related pollutants (NOX, and eBC at both sites). The meteorological conditions, also had an impact on the PNSD and eBC at both sites. During the measurement period, the frequency of NPF events was calculated to be 13.3%, and 22.2% at AURN and BF sites, respectively. The average value of formation and growth rates of nucleation mode particles were 1.3, and 1.17 cm-3 s-1 and 7.42, and 5.3 nm h-1 at AURN, and BF sites, respectively. It can suggested that aerosol particles in Leicester originate mainly

Estimating concentrations of fine-grained and total suspended sediment from close-range remote sensing imagery

Science.gov (United States)

Mosbrucker, Adam; Spicer, Kurt R.; Christianson, Tami; Uhrich, Mark A.

2015-01-01

data range among sensors. Of greatest interest to many programs is a hysteresis in the relationship between turbidity and SSC, attributed to temporal variation of particle size distribution (Landers and Sturm, 2013; Uhrich et al., 2014). This phenomenon causes increased uncertainty in regression-estimated values of SSC, due to changes in nephelometric reflectance off the varying grain sizes in suspension (Uhrich et al., 2014). Here, we assess the feasibility and application of close-range remote sensing to quantify SSC and particle size distribution of a disturbed, and highly-turbid, river system. We use a consumer-grade digital camera to acquire imagery of the river surface and a depth-integrating sampler to collect concurrent suspended-sediment samples. We then develop two empirical linear regression models to relate image spectral information to concentrations of fine sediment (clay to silt) and total suspended sediment. Before presenting our regression model development, we briefly summarize each data-acquisition method.

Deriving Total Suspended Matter Concentration from the Near-Infrared-Based Inherent Optical Properties over Turbid Waters: A Case Study in Lake Taihu

Directory of Open Access Journals (Sweden)

Wei Shi

2018-02-01

Full Text Available Normalized water-leaving radiance spectra nLw(λ, particle backscattering coefficients bbp(λ in the near-infrared (NIR wavelengths, and total suspended matter (TSM concentrations over turbid waters are analytically correlated. To demonstrate the use of bbp(λ in the NIR wavelengths in coastal and inland waters, we used in situ optics and TSM data to develop two TSM algorithms from measurements of the Visible Infrared Imaging Radiometer Suite (VIIRS onboard the Suomi National Polar-orbiting Partnership (SNPP using backscattering coefficients at the two NIR bands bbp(745 and bbp(862 for Lake Taihu. The correlation coefficients between the modeled TSM concentrations from bbp(745 and bbp(862 and the in situ TSM are 0.93 and 0.92, respectively. A different in situ dataset acquired between 2012 and 2016 for Lake Taihu was used to validate the performance of the NIR TSM algorithms for VIIRS-SNPP observations. TSM concentrations derived from VIIRS-SNPP observations with these two NIR bbp(λ-based TSM algorithms matched well with in situ TSM concentrations in Lake Taihu between 2012 and 2016. The normalized root mean square errors (NRMSEs for the two NIR algorithms are 0.234 and 0.226, respectively. The two NIR-based TSM algorithms are used to compute the satellite-derived TSM concentrations to study the seasonal and interannual variability of the TSM concentration in Lake Taihu between 2012 and 2016. In fact, the NIR-based TSM algorithms are analytically based with minimal in situ data to tune the coefficients. They are not sensitive to the possible nLw(λ saturation in the visible bands for highly turbid waters, and have the potential to be used for estimation of TSM concentrations in turbid waters with similar NIR nLw(λ spectra as those in Lake Taihu.

Lipoprotein particle distribution and skeletal muscle lipoprotein lipase activity after acute exercise.

Science.gov (United States)

Harrison, Michael; Moyna, Niall M; Zderic, Theodore W; O'Gorman, Donal J; McCaffrey, Noel; Carson, Brian P; Hamilton, Marc T

2012-07-10

Many of the metabolic effects of exercise are due to the most recent exercise session. With recent advances in nuclear magnetic resonance spectroscopy (NMRS), it is possible to gain insight about which lipoprotein particles are responsible for mediating exercise effects. Using a randomized cross-over design, very low density lipoprotein (VLDL) responses were evaluated in eight men on the morning after i) an inactive control trial (CON), ii) exercising vigorously on the prior evening for 100 min followed by fasting overnight to maintain an energy and carbohydrate deficit (EX-DEF), and iii) after the same exercise session followed by carbohydrate intake to restore muscle glycogen and carbohydrate balance (EX-BAL). The intermediate, low and high density lipoprotein particle concentrations did not differ between trials. Fasting triglyceride (TG) determined biochemically, and mean VLDL size were lower in EX-DEF but not in EX-BAL compared to CON, primarily due to a reduction in VLDL-TG in the 70-120 nm (large) particle range. In contrast, VLDL-TG was lower in both EX-DEF and EX-BAL compared to CON in the 43-55 nm (medium) particle range. VLDL-TG in smaller particles (29-43 nm) was unaffected by exercise. Because the majority of VLDL particles were in this smallest size range and resistant to change, total VLDL particle concentration was not different between any of these conditions. Skeletal muscle lipoprotein lipase (LPL) activity was also not different across these 3 trials. However, in CON only, the inter-individual differences in LPL activity were inversely correlated with fasting TG, VLDL-TG, total, large and small VLDL particle concentration and VLDL size, indicating a regulatory role for LPL in the non-exercised state. These findings reveal a high level of differential regulation between different sized triglyceride-rich lipoproteins following exercise and feeding, in the absence of changes in LPL activity.

Radionuclides and particles in seawater with the large volume in situ filtration and concentration system in the coastal waters off Japan

International Nuclear Information System (INIS)

Aono, Tatsuo; Nakanishi, Takahiro; Okubo, Ayako; Zheng, Jian; Yamada, Masatoshi; Kusakabe, Masashi

2008-01-01

It is necessary to determine the radionuclides in dissolved and particulate state in order to clarify the distributions and behavior of these in seawater. Because the concentrations of radionuclides and particles are very low in the ocean, it is difficult to concentrate and fractionate the particulate matters with the filtration systems in seawater. The large volume in situ filtration and concentration system (LV-FiCS) was developed to collect various forms of trace radionuclides and particles in seawater. The LV-FiCS has been operated during several cruises in the coastal waters off Japan, and several m 3 of seawaters were filtered through different kinds of filters and then pass through the adsorbents to concentrate radionuclides simultaneously. This system could be shown the vertical profiles of thorium with the size-fractionated method and the behavior of these nuclides in the ocean. (author)

Total concentration and speciation of heavy metals in biosolids from urban origin; Concentracion total y especiacion de metales pesados en biosolidos de origen urbano origin

Energy Technology Data Exchange (ETDEWEB)

Gonzalez Flores, Eduardo [Laboratorio de Ingenieria Ambiental, Instituto Tecnologico de Puebla, Puebla, Puebla (Mexico)]. E-mail: egonz1962@yahoo.com.mx; Tornero Campante, Mario Alberto [Colegio de Postgraduados - Campus Puebla, San Pedro Cholula, Puebla (Mexico); Angeles Cruz, Yolanda [Laboratorio de Ingenieria Ambiental, Instituto Tecnologico de Puebla, Puebla, Puebla (Mexico); Bonilla y Fernandez, Noemi [Departamento de Agroecologia y Ambiente, Instituto de Ciencias - Benemerita Universidad Autonoma de Puebla, Puebla, Puebla (Mexico)

2009-02-15

The analysis of heavy metals is a very important task to asses the potential environmental and health risk associated with biosolids deposition in agricultural soil. However, it is widely accepted that determination of total concentration of heavy metals does not give an accurate estimation of the potential environmental impact. So, it is necessary to apply speciation studies to obtain suitable information about their bioavailability. This study was carried out on sewage sludge samples collected in a municipal waste-water treatment plant, located in Puebla City (Mexico). They are used for amendment agricultural soil. The speciation of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) was made using a sequential extraction procedure. The aim was to determine their concentration in bioavailability fractions. It was got the total concentration of heavy metals using acid digestion in a closed system and was determined with atomic absorption spectrometry. The total concentrations of heavy metals were lower than that established by Mexican legislation. The heavy metals are mainly associated with the mineral fraction and organic matter and consequently they show low bioavailability. [Spanish] El analisis de metales pesados es una actividad importante cuando se quiere valorar el potencial riesgo ambiental y de salud asociado con la utilizacion de biosolidos en suelos agricolas. Sin embargo, es ampliamente aceptado que la determinacion del contenido total no da una valoracion apropiada del impacto ambiental causado. Por lo tanto, es necesario realizar estudios de especiacion para obtener informacion mas detallada sobre su biodisponibilidad. Este estudio se llevo a cabo con muestras de lodos residuales producidos en una planta de tratamiento de aguas residuales ubicada en la ciudad de Puebla (Mexico). Estos biosolidos son utilizados para enmendar suelos agricolas. La especiacion de metales pesados (Cd, Cr, Cu, Ni, Pb y Zn) se realizo usando un procedimiento de extraccion secuencial

Investigations into the penetration and pressure drop of HEPA filter media during loading with submicron particle aerosols at high concentrations

International Nuclear Information System (INIS)

Leibold, H; Wilhelm, J.G.

1991-01-01

High Efficiency Particulate Air (HEPA) filters are typically employed in particle removal and retention within the air cleaning systems of clean rooms in the pharmaceutical, nuclear and semiconductor industries for dust concentrations of some μg/m 3 . Their extremely high removal efficiencies for submicron particles make them attractive candidates in complying with increasingly lower emission limits for industrial processes that involve dust concentrations of up to several g/m 3 . Cost-effective operation under such conditions requires the filter units to be recleanable. The recleanability of HEPA filter media depends not only on the operating conditions during the cleaning process but also on the filtration conditions during particle loading. The structure and location of the particles captured by the glass fiber matrix greatly affect the degree to which they can be subsequently dislodged and removed from the filter medium. Changes in filtration efficiency with service time for various particle diameters in the critical submicron size range, as well as the effects of filtration velocity on the increase in pressure drop, are important criteria with regard to recleaning HEPA filter units. Of special significance for the recleanability of HEPA filter media is knowledge of how operating conditions affect dust cake formation. (author)

Physicochemical characteristics and occupational exposure to coarse, fine and ultrafine particles during building refurbishment activities

Energy Technology Data Exchange (ETDEWEB)

Azarmi, Farhad; Kumar, Prashant, E-mail: p.kumar@surrey.ac.uk, E-mail: prashant.kumar@cantab.net; Mulheron, Mike [University of Surrey, Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences (United Kingdom); Colaux, Julien L.; Jeynes, Chris [University of Surrey, Faculty of Engineering and Physical Sciences, Ion Beam Centre (United Kingdom); Adhami, Siavash; Watts, John F. [University of Surrey, The Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences (United Kingdom)

2015-08-15

Understanding of the emissions of coarse (PM{sub 10} ≤10 μm), fine (PM{sub 2.5} ≤2.5 μm) and ultrafine particles (UFP <100 nm) from refurbishment activities and their dispersion into the nearby environment is of primary importance for developing efficient risk assessment and management strategies in the construction and demolition industry. This study investigates the release, occupational exposure and physicochemical properties of particulate matter, including UFPs, from over 20 different refurbishment activities occurring at an operational building site. Particles were measured in the 5–10,000-nm-size range using a fast response differential mobility spectrometer and a GRIMM particle spectrometer for 55 h over 8 days. The UFPs were found to account for >90 % of the total particle number concentrations and <10 % of the total mass concentrations released during the recorded activities. The highest UFP concentrations were 4860, 740, 650 and 500 times above the background value during wall-chasing, drilling, cementing and general demolition activities, respectively. Scanning electron microscopy, X-ray photoelectron spectroscopy and ion beam analysis were used to identify physicochemical characteristics of particles and attribute them to probable sources considering the size and the nature of the particles. The results confirm that refurbishment activities produce significant levels (both number and mass) of airborne particles, indicating a need to develop appropriate regulations for the control of occupational exposure of operatives undertaking building refurbishment.

Size distribution and total number concentration of ultrafine and accumulation mode particles and hospital admissions in children and the elderly in Copenhagen, Denmark

DEFF Research Database (Denmark)

Andersen, Zorana Jovanovic; Wåhlin, Peter; Raaschou-Nielsen, O

2008-01-01

(15 May 2001 to 31 December 2004) and hospital admissions due to cardiovascular (CVD) and respiratory disease (RD) in the elderly (age >or=65 years), and due to asthma in children (age 5-18 years). We examined these associations in the presence of PM(10), PM(2.5) (particulate matter ... that particle volume/mass from long-range transported air pollution is relevant for CVD and RD admissions in the elderly, and possibly particle numbers from traffic sources for paediatric asthma....

Measurements of ultrafine particles and other vehicular pollutants inside school buses in South Texas

Science.gov (United States)

Zhang, Qunfang; Zhu, Yifang

2010-01-01

Increasing evidence has demonstrated toxic effects of vehicular emitted ultrafine particles (UFPs, diameter pollutants, especially UFPs, was measured inside four diesel-powered school buses. Two 1990 and two 2006 model year diesel-powered school buses were selected to represent the age extremes of school buses in service. Each bus was driven on two routine bus runs to study school children's exposure under different transportation conditions in South Texas. The number concentration and size distribution of UFPs, total particle number concentration, PM 2.5, PM 10, black carbon (BC), CO, and CO 2 levels were monitored inside the buses. The average total particle number concentrations observed inside the school buses ranged from 7.3 × 10 3 to 3.4 × 10 4 particles cm -3, depending on engine age and window position. When the windows were closed, the in-cabin air pollutants were more likely due to the school buses' self-pollution. The 1990 model year school buses demonstrated much higher air pollutant concentrations than the 2006 model year ones. When the windows were open, the majority of in-cabin air pollutants came from the outside roadway environment with similar pollutant levels observed regardless of engine ages. The highest average UFP concentration was observed at a bus transfer station where approximately 27 idling school buses were queued to load or unload students. Starting-up and idling generated higher air pollutant levels than the driving state. Higher in-cabin air pollutant concentrations were observed when more students were on board.

Single-particle characterization of summertime Antarctic aerosols collected at King George Island using quantitative energy-dispersive electron probe X-ray microanalysis and attenuated total reflection Fourier transform-infrared imaging techniques.

Science.gov (United States)

Maskey, Shila; Geng, Hong; Song, Young-Chul; Hwang, Heejin; Yoon, Young-Jun; Ahn, Kang-Ho; Ro, Chul-Un

2011-08-01

Single-particle characterization of Antarctic aerosols was performed to investigate the impact of marine biogenic sulfur species on the chemical compositions of sea-salt aerosols in the polar atmosphere. Quantitative energy-dispersive electron probe X-ray microanalysis was used to characterize 2900 individual particles in 10 sets of aerosol samples collected between March 12 and 16, 2009 at King Sejong Station, a Korean scientific research station located at King George Island in the Antarctic. Two size modes of particles, i.e., PM(2.5-10) and PM(1.0-2.5), were analyzed, and four types of particles were identified, with sulfur-containing sea-salt particles being the most abundant, followed by genuine sea-salt particles without sulfur species, iron-containing particles, and other species including CaCO(3)/CaMg(CO(3))(2), organic carbon, and aluminosilicates. When a sulfur-containing sea-salt particle showed an atomic concentration ratio of sulfur to sodium of >0.083 (seawater ratio), it is regarded as containing nonsea-salt sulfate (nss-SO(4)(2-)) and/or methanesulfonate (CH(3)SO(3)(-)), which was supported by attenuated total reflection Fourier transform-infrared imaging measurements. These internal mixture particles of sea-salt/CH(3)SO(3)(-)/SO(4)(2-) were very frequently encountered. As nitrate-containing particles were not encountered, and the air-masses for all of the samples originated from the Pacific Ocean (based on 5-day backward trajectories), the oxidation of dimethylsulfide (DMS) emitted from phytoplanktons in the ocean is most likely to be responsible for the formation of the mixed sea-salt/CH(3)SO(3)(-)/SO(4)(2-) particles.

Wide-range particle characterization and elemental concentration in Beijing aerosol during the 2013 Spring Festival.

Science.gov (United States)

Jing, Hui; Li, Yu-Feng; Zhao, Jiating; Li, Bai; Sun, Jialong; Chen, Rui; Gao, Yuxi; Chen, Chunying

2014-09-01

The number and mass concentration, size distribution, and the concentration of 16 elements were studied in aerosol samples during the Spring Festival celebrations in 2013 in Beijing, China. Both the number and mass concentration increased sharply in a wide range from 10 nm to 10 μm during the firecrackers and fireworks activities. The prominent increase of the number concentration was in 50 nm-500 nm with a peak of 1.7 × 10(5)/cm(3) at 150 nm, which is 8 times higher than that after 1.5 h. The highest mass concentration was in 320-560 nm, which is 4 times higher than the control. K, Mg, Sr, Ba and Pb increased sharply during the firework activities in PM10. Although the aerosol emission from firework activities is a short-term air quality degradation event, there may be a substantial hazard arising from the chemical composition of the emitted particles. Copyright © 2014 Elsevier Ltd. All rights reserved.

Diurnal salivary cortisol concentrations in Parkinson’s disease: increased total secretion and morning cortisol concentrations

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Skogar Ö

2011-08-01

Full Text Available Ö Skogar1,4, P-A Fall2, G Hallgren3, J Lökk4, B Bringer2, M Carlsson1, U Lennartsson3, H Sandbjork3, C-J Törnhage51Department of Geriatrics, Ryhov Hospital, Jonkoping, 2Department of Geriatrics, University Hospital, Linkoping, 3Department of Neurology, Skaraborg Hospital, Skovde, 4Institute of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, 5Department of Pediatrics, Skaraborg Hospital, Skövde, SwedenBackground: Parkinson’s disease (PD is a chronic neurodegenerative disorder. There is limited knowledge about the function of the hypothalamic-pituitary-adrenal axis in PD. The primary aim of this prospective study was to analyze diurnal salivary cortisol concentrations in patients with PD and correlate these with age, gender, body mass index (BMI, duration of PD, and pain. The secondary aim was to compare the results with a healthy reference group.Methods: Fifty-nine PD patients, 35 women and 24 men, aged 50–79 years, were recruited. The reference group comprised healthy individuals matched for age, gender, BMI, and time point for sampling. Salivary cortisol was collected at 8 am, 1 pm, and 8 pm, and 8 am the next day using cotton-based Salivette® tubes and analyzed using Spectria® Cortisol I125. A visual analog scale was used for estimation of pain.Results: The median cortisol concentration was 16.0 (5.8–30.2 nmol/L at 8 am, 5.8 (3.0–16.4 at 1 pm, 2.8 (1.6–8.0 at 8 pm, and 14.0 (7.5–28.7 at 8 am the next day. Total secretion and rate of cortisol secretion during the day (8 am–8 pm and the concentration of cortisol on the next morning were lower (12.5 nmol/L in the reference group. No significant correlations with age, gender, BMI, duration of PD, Hoehn and Yahr score, Unified Parkinson’s Disease Rating Scale III score, gait, pain, or cortisol concentrations were found.Conclusion: The neurodegenerative changes in PD does not seem to interfere with the

Analysis of Particulate matter (PM 10 and PM 2.5 concentration in Khorramabad city

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Seyed Hamed Mirhosseini

2013-01-01

Full Text Available Aims: In this study, the concentration of PM10 and PM2.5 in eight station of Khorramabad city was analyzed. Materials and Methods: For this study, the data were taken from April 2010 to March 2011. The eight sampling point were chosen in account to Khorramabad maps. During this period, 240 daily PM samples including coarse particle (PM 10 and fine particle (PM 2.5 were collected. A two-part sampler was used to collect samples of PM. According to one-way ANOVA, multiple comparisons Scheffe, the obtained data were analyzed and then compared with the Environment protection organization standard rates. Khorramabad Results: The results revealed that during measuring the maximum concentration of PM 10 and PM 2.5 was respectively 120.9 and 101.09 μ/m 3 at Shamshirabad station. There was a significant difference between the mean values of PM 10 concentration (μg/m 3 in the seasons of summer. In addition, the mean concentrations of PM 10 in warmer months exceeded to the maximum permissible concentration. Conclusions: Year comparison of PM 10 and PM 2.5 concentration with standard were revealed particle matter concentration in summer season was higher than standard. Although total mean of particle matter was less than standard concentration.

Beyond phthalates: Gas phase concentrations and modeled gas/particle distribution of modern plasticizers

Energy Technology Data Exchange (ETDEWEB)

Schossler, Patricia [Fraunhofer WKI, Department of Material Analysis and Indoor Chemistry, Bienroder Weg 54E, D-38108 Braunschweig (Germany); Institute of Environmental and Sustainable Chemistry, Technische Universitaet Braunschweig, Hagenring 30, D-38106 Braunschweig (Germany); Schripp, Tobias, E-mail: tobias.schripp@wki.fraunhofer.de [Fraunhofer WKI, Department of Material Analysis and Indoor Chemistry, Bienroder Weg 54E, D-38108 Braunschweig (Germany); Salthammer, Tunga [Fraunhofer WKI, Department of Material Analysis and Indoor Chemistry, Bienroder Weg 54E, D-38108 Braunschweig (Germany); Bahadir, Muefit [Institute of Environmental and Sustainable Chemistry, Technische Universitaet Braunschweig, Hagenring 30, D-38106 Braunschweig (Germany)

2011-09-01

The ongoing health debate about polymer plasticizers based on the esters of phthalic acid, especially di(2-ethylhexyl) phthalate (DEHP), has caused a trend towards using phthalates of lower volatility such as diisononyl phthalate (DINP) and towards other acid esters, such as adipates, terephthalates, citrates, etc. Probably the most important of these so-called 'alternative' plasticizers is diisononyl cyclohexane-1,2-dicarboxylate (DINCH). In the indoor environment, the continuously growing market share of this compound since its launch in 2002 is inter alia apparent from the increasing concentration of DINCH in settled house dust. From the epidemiological point of view there is considerable interest in identifying how semi-volatile organic compounds (SVOCs) distribute in the indoor environment, especially in air, airborne particles and sedimented house dust. This, however, requires reliable experimental concentration data for the different media and good measurements or estimates of their physical and chemical properties. This paper reports on air concentrations for DINP, DINCH, diisobutyl phthalate (DIBP), diisobutyl adipate (DIBA), diisobutyl succinate (DIBS) and diisobutyl glutarate (DIBG) from emission studies in the Field and Laboratory Emission Cell (FLEC). For DINP and DINCH it took about 50 days to reach the steady-state value: for four months no decay in the concentration could be observed. Moreover, vapor pressures p{sub 0} and octanol-air partitioning coefficients K{sub OA} were obtained for 37 phthalate and non-phthalate plasticizers from two different algorithms: EPI Suite and SPARC. It is shown that calculated gas/particle partition coefficients K{sub p} and fractions can widely differ due to the uncertainty in the predicted p{sub 0} and K{sub OA} values. For most of the investigated compounds reliable experimental vapor pressures are not available. Rough estimates can be obtained from the measured emission rate of the pure compound in a

Personal exposure to ultrafine particles.

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Wallace, Lance; Ott, Wayne

2011-01-01

Personal exposure to ultrafine particles (UFP) can occur while people are cooking, driving, smoking, operating small appliances such as hair dryers, or eating out in restaurants. These exposures can often be higher than outdoor concentrations. For 3 years, portable monitors were employed in homes, cars, and restaurants. More than 300 measurement periods in several homes were documented, along with 25 h of driving two cars, and 22 visits to restaurants. Cooking on gas or electric stoves and electric toaster ovens was a major source of UFP, with peak personal exposures often exceeding 100,000 particles/cm³ and estimated emission rates in the neighborhood of 10¹² particles/min. Other common sources of high UFP exposures were cigarettes, a vented gas clothes dryer, an air popcorn popper, candles, an electric mixer, a toaster, a hair dryer, a curling iron, and a steam iron. Relatively low indoor UFP emissions were noted for a fireplace, several space heaters, and a laser printer. Driving resulted in moderate exposures averaging about 30,000 particles/cm³ in each of two cars driven on 17 trips on major highways on the East and West Coasts. Most of the restaurants visited maintained consistently high levels of 50,000-200,000 particles/cm³ for the entire length of the meal. The indoor/outdoor ratios of size-resolved UFP were much lower than for PM₂.₅ or PM₁₀, suggesting that outdoor UFP have difficulty in penetrating a home. This in turn implies that outdoor concentrations of UFP have only a moderate effect on personal exposures if indoor sources are present. A time-weighted scenario suggests that for typical suburban nonsmoker lifestyles, indoor sources provide about 47% and outdoor sources about 36% of total daily UFP exposure and in-vehicle exposures add the remainder (17%). However, the effect of one smoker in the home results in an overwhelming increase in the importance of indoor sources (77% of the total).

Evaluation of the trace elements and the total mercury concentration in fishes commercialized at the Cubatao city, Sao Paulo, Brazil

International Nuclear Information System (INIS)

Fonseca, Barbara C.; Farias, Luciana A.; Curcho, Michel R.M.; Favaro, Debora I.T.; Braga, Elisabete S.

2009-01-01

This paper evaluates the total Hg and the trace elements As, Br, Co, Cr and Rb concentrations in muscle of commercially important fishes at the Cubatao, Sao Paulo, Brazil, region. The following carnivore species were analysed: jew fish (Micropogonias furnieri), girl leg (Menticirrhus americanus), hake (Macrodon ancylodon), and plant eaters, sardine (Sardella braziliensis) and grey mullet (Mugil liza), representing a total of 58 samples. The analysed trace elements were determined through the neutron analysis activation (NAA) and total Hg, through the atomic absorption spectrometry with cold vapor generation (CV AAS). The analysed elements present a great concentration variation, not only among individuals of the same specie, but also among all the analysed species. The total Hg concentration were highly significant, with the predator species jew fish, girl leg and hake presenting concentrations larger than the non predator species sardine and grey mullet. Nevertheless, the content of total Hg remained bellow the limits established by the Brazilian legislation which is the 500 μg kg -1 for the non predator species, and the 1000 μg -1 for the predator species (humid weight)

Abundant plankton-sized microplastic particles in shelf waters of the northern Gulf of Mexico.

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Di Mauro, Rosana; Kupchik, Matthew J; Benfield, Mark C

2017-11-01

Accumulation of marine debris is a global problem that affects the oceans on multiple scales. The majority of floating marine debris is composed of microplastics: plastic particles up to 5 mm in diameter. With similar sizes and appearances to natural food items, these small fragments pose potential risks to many marine organisms including zooplankton and zooplanktivores. Semi-enclosed seas are reported to have high concentrations of microplastics, however, the distribution and concentration of microplastics in one such system, the Gulf of Mexico, remains unknown. Our study documented and characterized microplastics in continental shelf waters off the Louisiana coast in the northern Gulf of Mexico, using bongo nets, neuston nets, and Niskin bottles. Additionally, we compared the size distributions of microplastics and zooplankton collected using the nets. Plastics were manually sorted from the samples, documented, and measured using digital microscopy. Confirmation of putative plastics was carried out by hydrofluoric acid digestion and a subsample was analyzed using FTIR microscopy. Estimated concentrations of microplastics collected on the inner continental shelf during this study are among the highest reported globally. Total microplastic concentrations ranged from 4.8 to 8.2 particles m -3 and 5.0-18.4 particles m -3 for the bongo and neuston samples, respectively. Niskin bottles collected smaller plastic particles than the nets and indicated total microplastic concentrations (primarily fibers) from 6.0E4 - 15.7E4 particles m -3 . Microplastic concentrations were greater than the abundances of all but four of the five most abundant taxa from bongo nets and were not statistically different from the abundances of any of the most numerous taxa from neuston nets. Sizes of microplastics and zooplankton partially or completely overlapped, suggesting the potential for confusion with natural prey. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of initial total solids concentration on volatile fatty acid production from food waste during anaerobic acidification.

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Wang, Quan; Jiang, Jianguo; Zhang, Yujing; Li, Kaimin

2015-01-01

The effect of initial total solids (TS) concentration on volatile fatty acid (VFAs) production from food waste under mesophilic conditions (35 °C) was determined. VFAs concentration and composition, biogas production, soluble chemical oxygen demand concentration, TS and volatile solids (VS) reduction, and ammonia nitrogen [Formula: see text] release were investigated. The VFAs concentrations were 26.10, 39.68, 59.58, and 62.64 g COD/L at TS contents of 40, 70, 100, and 130 g/L, respectively. While the VFAs' yields ranged from 0.467 to 0.799 g COD/g VSfed, decreased as initial TS increased. The percentage of propionate was not affected by TS concentration, accounting for 30.19-34.86% of the total VFAs, while a higher percentage of butyrate and lower percentage of acetate was achieved at a higher TS concentration. Biogas included mainly hydrogen and carbon dioxide and the maximum hydrogen yield of 148.9 ml/g VSfed was obtained at 130 g TS/L. [Formula: see text] concentration, TS and VS reductions increased as initial TS increased. Considering the above variables, we conclude that initial TS of 100 g/L shall be the most appropriate to VFAs production.

Effect of biomass open burning on particulate matter and polycyclic aromatic hydrocarbon concentration levels and PAH dry deposition in ambient air.

Science.gov (United States)

Chiu, Jui C; Shen, Yun H; Li, Hsing W; Chang, Shun S; Wang, Lin C; Chang-Chien, Guo P

2011-01-01

The objectives of the present study were to investigate particulate matter (PM) and polycyclic aromatic hydrocarbon (PAH) concentrations in ambient air during rice straw open burning and non-open burning periods. In the ambient air of a rice field, the mean PM concentration during and after an open burning event were 1828 and 102 μg m⁻³, respectively, which demonstrates that during a rice field open burning event, the PM concentration in the ambient air of rice field is over 17 times higher than that of the non-open burning period. During an open burning event, the mean total PAH and total toxic equivalence (BaP(eq)) concentrations in the ambient air of a rice field were 7206 ng m⁻³ and 10.3 ng m⁻³, respectively, whereas after the open burning event, they were 376 ng m⁻³ and 1.50 ng m⁻³, respectively. Open burning thus increases total PAH and total BaP(eq) concentrations by 19-fold and 6.8-fold, respectively. During a rice straw open burning event, in the ambient air of a rice field, the mean dry deposition fluxes of total PAHs and total BaP(eq) were 1222 μg m⁻² day⁻¹ and 4.80 μg m⁻² day⁻¹, respectively, which are approximately 60- and 3-fold higher than those during the non-open burning period, respectively. During the non-open burning period, particle-bound PAHs contributed 79.2-84.2% of total dry deposition fluxes (gas + particle) of total PAHs. However, an open burning event increases the contribution to total PAH dry deposition by particle-bound PAHs by up to 85.9-95.5%. The results show that due to the increased amount of PM in the ambient air resulting from rice straw open burning, particle-bound PAHs contributed more to dry deposition fluxes of total PAHs than they do during non-open burning periods. The results show that biomass (rice straw) open burning is an important PAH emission source that significantly increases both PM and PAH concentration levels and PAH dry deposition in ambient air.

Atmospheric particles acting as ice forming nuclei in different size ranges and cloud condensation nuclei measurements

International Nuclear Information System (INIS)

Santachiara, G.; Di Matteo, L.; Belosi, F.; Prodi, F.

2009-01-01

Measurements of ice nuclei (I N) in different size classes of aerosol P M1, P M2.5, PM10, and total suspended particles (Tsp) were performed at a rural site (S.Pietro Capofiume, in the Po Valley, Italy). Simultaneous measurements of particle number concentrations were also made with a condensation nucleus counter (CN C-TSI), along with particle concentration in different size classes starting from diameter d > 0.3 μm (Optical Spectrometer Grimm, Mod.1.108). No correlation is observed between I N and the particle number concentration measured with the condensation nuclei counter, and there is only a weak correlation with the particle concentration measured using the optical counter, thus confirming the contribution of the accumulation and coarse aerosol fraction. A positive correlation is observed between supersaturation with respect to ice and water values and ice nuclei number concentration, and an exponential dependence of I N on temperature is found. In addition, cloud concentration nuclei (C CN) were measured. The present measurements reveal a diurnal trend, with lower values at about midday and higher ones during the night, a similar trend between C CN and the relative humidity, and opposite to the mixing layer height.

A summary of total mercury concentrations in flora and fauna near common contaminant sources in the Gulf of Mexico.

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Lewis, M; Chancy, C

2008-02-01

Total mercury concentrations are summarized for environmental media and biota collected from near-coastal areas, several impacted by contaminant sources common to the Gulf of Mexico. Water, sediment, fish, blue crabs, oysters, clams, mussels, periphyton and seagrasses were collected during 1993-2002 from targeted areas affected by point and non-point source contaminants. Mean concentrations in water and sediment were 0.02 (+/-1 standard deviation=0.06) microg l(-1) and 96.3 (230.8) ng g(-1) dry wt, respectively. Mean total mercury concentrations in fish, blue crabs, brackish clams and mussels were significantly greater than those in sediment, seagrass, colonized periphyton and oysters. Concentrations (ng g(-1) dry wt) averaged 23.1 (two seagrass species), 220.1 (oysters), 287.8 (colonized periphyton), 604.0 (four species of freshwater mussels), 772.4 (brackish clam), 857.9 (blue crabs) and 933.1 (nine fish species). Spatial, intraspecific and interspecific variability in results limited most generalizations concerning the relative mercury contributions of different stressor types. However, concentrations were significantly greater for some biota collected from areas receiving wastewater discharges and golf course runoff (fish), agricultural runoff (oysters) and urban stormwater runoff (colonized periphyton and sediment). Marine water quality criteria and proposed sediment quality guidelines were exceeded in 1-12% of total samples. At least one seafood consumption guideline, criteria or screening value were exceeded in edible tissues of blue crabs (6% total samples) and nine fish species (8-33% total samples) but all residues were less than the US Federal Drug Administration action limit of 1.0 ppm and the few reported toxic effect concentrations available for the targeted biota.

Concentration of total protein and degree of acidity (pH of saliva when fasting and after breakfasting

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Gemella Nur Illahi

2016-04-01

Full Text Available Background: While fasting, the mouth does not work to eat and drink so that the salivary glands become less active so saliva production decreased and there was a change in eating timewhich is relation to the mastication process that impact on changes in the degree of acidity (pH Objectives: To determine the concentration of total protein and the degree of acidity (pH of saliva when fasting and after breakfasting. Materials and Methods: The study was observational analytic design with longitudinal (follow up study conducted in the Hj. Halima Dg. Sikati Dental Hospital inKandea in July 2015, the sampling method was purposive sampling. Population was 35 clinical students at the Department of Dental Public Health, Faculty of Dentistry Hasanuddin University with a total sample of 16 students who fit the criteria of the study subjects. To calculate the total protein of saliva concentration using Kyltecautoanalyzerand pH meter to measure the acidity of saliva. Data was analyzed was using SPSS version 17.0 (paired t-test, p <0.05. Results: The mean of total protein (% while fasting by 0135% ± 0.026 and the mean total protein (% after breakfasting at 0.179% ± 0.035, while the average degree of acidity (pH during fasting at 7.26 ± 0:24 and the average degree of acidity (pH after breakfasting at 7.66 ± 0.23 with p-value (0.000. Conclusions: An increase in the total protein concentration and acidity (pH after breakfasting.

Wintertime water-soluble aerosol composition and particle water content in Fresno, California

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Parworth, Caroline L.; Young, Dominique E.; Kim, Hwajin; Zhang, Xiaolu; Cappa, Christopher D.; Collier, Sonya; Zhang, Qi

2017-03-01

The composition and concentrations of water-soluble gases and ionic aerosol components were measured from January to February 2013 in Fresno, CA, with a particle-into-liquid sampler with ion chromatography and annular denuders. The average (±1σ) ionic aerosol mass concentration was 15.0 (±9.4) µg m-3, and dominated by nitrate (61%), followed by ammonium, sulfate, chloride, potassium, nitrite, and sodium. Aerosol-phase organic acids, including formate and glycolate, and amines including methylaminium, triethanolaminium, ethanolaminium, dimethylaminium, and ethylaminium were also detected. Although the dominant species all came from secondary aerosol formation, there were primary sources of ionic aerosols as well, including biomass burning for potassium and glycolate, sea spray for sodium, chloride, and dimethylamine, and vehicles for formate. Particulate methanesulfonic acid was also detected and mainly associated with terrestrial sources. On average, the molar concentration of ammonia was 49 times greater than nitric acid, indicating that ammonium nitrate formation was limited by nitric acid availability. Particle water was calculated based on the Extended Aerosol Inorganics Model (E-AIM) thermodynamic prediction of inorganic particle water and κ-Köhler theory approximation of organic particle water. The average (±1σ) particle water concentration was 19.2 (±18.6) µg m-3, of which 90% was attributed to inorganic species. The fractional contribution of particle water to total fine particle mass averaged at 36% during this study and was greatest during early morning and night and least during the day. Based on aqueous-phase concentrations of ions calculated by using E-AIM, the average (±1σ) pH of particles in Fresno during the winter was estimated to be 4.2 (±0.2).

Effects of locust bean gum and mono- and diglyceride concentrations on particle size and melting rates of ice cream.

Science.gov (United States)

Cropper, S L; Kocaoglu-Vurma, N A; Tharp, B W; Harper, W J

2013-06-01

The objective of this study was to determine how varying concentrations of the stabilizer, locust bean gum (LBG), and different levels of the emulsifier, mono- and diglycerides (MDGs), influenced fat aggregation and melting characteristics of ice cream. Ice creams were made containing MDGs and LBG singly and in combination at concentrations ranging between 0.0% to 0.14% and 0.0% to 0.23%, respectively. Particle size analysis, conducted on both the mixes and ice cream, and melting rate testing on the ice cream were used to determine fat aggregation. No significant differences (P ice cream mixes. However, higher concentrations of both LBG and MDG in the ice creams resulted in values that were larger than the control. This study also found an increase in the particle size values when MDG levels were held constant and LBG amounts were increased in the ice cream. Ice creams with higher concentrations of MDG and LBG together had the greatest difference in the rate of melting than the control. The melting rate decreased with increasing LBG concentrations at constant MDG levels. These results illustrated that fat aggregation may not only be affected by emulsifiers, but that stabilizers may play a role in contributing to the destabilization of fat globules. © 2013 Institute of Food Technologists®