WorldWideScience

Sample records for carbon source concentration

  1. The Effect of Carbon Source and Fluoride Concentrations in the "Streptococcus Mutans" Biofilm Formation

    Science.gov (United States)

    Paulino, Tony P.; Andrade, Ricardo O.; Bruschi-Thedei, Giuliana C. M.; Thedei, Geraldo, Jr.; Ciancaglini, Pietro

    2004-01-01

    The main objective of this class experiment is to show the influence of carbon source and of different fluoride concentrations on the biofilm formation by the bacterium "Streptococcus mutans." The observation of different biofilm morphology as a function of carbon source and fluoride concentration allows an interesting discussion regarding the…

  2. At neutral pH the chronological lifespan of Hansenula polymorpha increases upon enhancing the carbon source concentrations

    OpenAIRE

    Adam Kawałek; van der Klei, Ida J

    2014-01-01

    Dietary restriction is generally assumed to increase the lifespan in most eukaryotes, including the simple model organism Saccharomyces cerevisiae. However, recent data questioned whether this phenomenon is indeed true for yeast. We studied the effect of reduction of the carbon source concentration on the chronological lifespan of the yeast Hansenula polymorpha using four different carbon sources. Our data indicate that reduction of the carbon source concentration has a negative (glucose, eth...

  3. Effect of carbon source and nitrate concentration on denitrifying phosphorus removal by DPB sludge

    Institute of Scientific and Technical Information of China (English)

    WANG Ya-yi; PENG Yong-zhen; Wang Shu-ying; PAN Mian-li

    2004-01-01

    Effect of added carbon source and nitrate concentration on the denitrifying phosphorus removal by DPB sludge was systematically studied using batch experiments, at the same time the variation of ORP was investigated.Results showed that the denitrifying and phosphorus uptake rate in anoxic phase increased with the high initial anaerobic carbon source addition. However once the initial COD concentration reached a certain level, which was in excess to the PHB saturation of poly-P bacteria, residual COD carried over to anoxic phase inhibited the subsequent denitrifying phosphorus uptake. Simultaneously, phosphate uptake continued until all nitrate was removed, following a slow endogenous release of phosphate. High nitrate concentration in anoxic phase increased the initial denitrifying phosphorus rate. Once the nitrate was exhausted, phosphate uptake changed to release. Moreover, the time of this turning point occurred later with the higher nitrate addition. On the other hand, through on-line monitoring the variation of the ORP with different initial COD concentration , it was found ORP could be used as a control parameter for phosphorus release, but it is impossible to utilize ORP for controlling the denitrificaion and anoxic phosphorus uptake operations.

  4. Concentration, sources and flux of dissolved organic carbon of precipitation at Lhasa city, the Tibetan Plateau

    Science.gov (United States)

    Li, C.

    2015-12-01

    Dissolved organic carbon (DOC) plays important role in climate system, but few data are available on the Tibetan Plateau (TP). In this study 89 precipitation samples were collected at Lhasa, the largest city of southern Tibet, from March to December 2013. The average concentration and wet deposition fluxes of DOC was 1.10 mg C/L and 0.62 g C m-2.yr-1, respectively. Seasonally, low DOC concentration and high flux appeared during monsoon period, which were in line with heavy precipitation amount, reflecting dilution effect of precipitation for the DOC. Compared to other regions, the values of Lhasa were lower than those of large cites (e.g. Beijing and Seoul) mainly because of less air pollution of Lhasa. The relationship between DOC and ion analysis showed that DOC of Lhasa was derived mainly from the natural sources, followed by burning activities. Furthermore, △14C value of DOC indicated that fossil combustion contributed around 20% of the precipitation DOC of Lhasa, indicating that the atmosphere of Lhasa has been influenced by vehicle emissions. Therefore, although atmosphere of Lhasa is relatively clean, pollutants emitted from local sources cannot be ignored.

  5. Hemicellulose concentration and composition in plant cell walls under extreme carbon source-sink imbalances

    Energy Technology Data Exchange (ETDEWEB)

    Schaedel, C.; Hoch, G. (Univ. of Basel, Institute of Botany, Basel (Switzerland)); Richter, A.; Bloechl, A. (Univ. of Vienna, Dept. of Chemical Ecology and Ecosystem Research, Vienna (Austria))

    2010-01-15

    Hemicelluloses account for one-quarter of the global dry plant biomass and therefore are the second most abundant biomass fraction after cellulose. Despite their quantitative significance, the responsiveness of hemicelluloses to atmospheric carbon oversupply is still largely unknown, although hemicelluloses could serve as carbon sinks with increasing CO{sub 2} concentrations. This study aimed at clarifying the role hemicelluloses play as carbon sinks, analogous to non-structural carbohydrates (NSC), by experimentally manipulating the plants' carbon supply. Sixteen plant species from four different plant functional types (grasses, herbs, seedlings of broad-leaved trees and conifers) were grown for 2 months in greenhouses at either extremely low (140 ppm), medium (280 ppm) or high (560 ppm) atmospheric CO{sub 2}concentrations, thus inducing situations of massive C-limitation or -oversupply. Above and below ground biomass as wellas NSC significantly increased in all species and tissues with increasing CO{sub 2}concentrations. Increasing CO{sub 2}concentrations had no significant effect on total hemicellulose concentrations in leaves and woody tissues in all species, except for two out of four grass species, where hemicellulose concentrations increased with atmospheric CO{sub 2}supply. Despite the overall stable total hemicellulose concentrations, the monosaccharide spectra of hemicelluloses showed a significant increase in glucose monomers in leaves of woody species as C-supply increased. In summary, total hemicellulose concentrations in de novo built biomass seem to be largely unaffected by changed atmospheric CO{sub 2}concentrations, while significant increases of hemicellulose-derived glucose with increasing CO{sub 2}concentrations in leaves of broad-leaved and conifer tree seedlings showed differential responses among the different hemicellulose classes in response to varying CO{sub 2}concentrations. (author)

  6. Hemicellulose concentration and composition in plant cell walls under extreme carbon source-sink imbalances.

    Science.gov (United States)

    Schädel, Christina; Richter, Andreas; Blöchl, Andreas; Hoch, Günter

    2010-07-01

    Hemicelluloses account for one-quarter of the global dry plant biomass and therefore are the second most abundant biomass fraction after cellulose. Despite their quantitative significance, the responsiveness of hemicelluloses to atmospheric carbon oversupply is still largely unknown, although hemicelluloses could serve as carbon sinks with increasing CO(2) concentrations. This study aimed at clarifying the role hemicelluloses play as carbon sinks, analogous to non-structural carbohydrates (NSC), by experimentally manipulating the plants' carbon supply. Sixteen plant species from four different plant functional types (grasses, herbs, seedlings of broad-leaved trees and conifers) were grown for 2 months in greenhouses at either extremely low (140 ppm), medium (280 ppm) or high (560 ppm) atmospheric CO(2) concentrations, thus inducing situations of massive C-limitation or -oversupply. Above and belowground biomass as well as NSC significantly increased in all species and tissues with increasing CO(2) concentrations. Increasing CO(2) concentrations had no significant effect on total hemicellulose concentrations in leaves and woody tissues in all species, except for two out of four grass species, where hemicellulose concentrations increased with atmospheric CO(2) supply. Despite the overall stable total hemicellulose concentrations, the monosaccharide spectra of hemicelluloses showed a significant increase in glucose monomers in leaves of woody species as C-supply increased. In summary, total hemicellulose concentrations in de novo built biomass seem to be largely unaffected by changed atmospheric CO(2) concentrations, while significant increases of hemicellulose-derived glucose with increasing CO(2) concentrations in leaves of broad-leaved and conifer tree seedlings showed differential responses among the different hemicellulose classes in response to varying CO(2) concentrations. PMID:20113432

  7. Effects of carbon source, phosphorus concentration, and several micronutrients on biomass and geosmin production by Streptomyces halstedii.

    Science.gov (United States)

    Schrader, K K; Blevins, W T

    2001-04-01

    The effects of various carbon sources, phosphorus concentration, and different concentrations of the micronutrients calcium, cobalt, copper, iron, manganese, potassium, and zinc were determined on biomass dry weight production, geosmin production, and geosmin/biomass (G/B) values for Streptomyces halstedii, a geosmin-producing actinomycete isolated from the sediment of an aquaculture pond. Of the substrates tested, maltose as a sole carbon source promoted maximal growth by S. halstedii while mannitol promoted maximal geosmin production, and galactose yielded the highest G/B values. Fish-food pellets and galactose were poor substrates for growth. Increasing phosphorus concentrations enhanced geosmin production and G/B values. Of the seven micronutrients tested, zinc, iron, and copper had the most profound effects on biomass and geosmin production. Increasing zinc concentrations promoted biomass production while inhibiting geosmin production and G/B values; increasing concentrations of copper and iron inhibited biomass and geosmin production. Increased copper concentrations had the greatest effect in preventing growth and geosmin production by S. halstedii.

  8. Physiology of Aspergillus niger in Oxygen-Limited Continuous Cultures: Influence of Aeration, Carbon Source Concentration and Dilution Rate

    DEFF Research Database (Denmark)

    Diano, Audrey; Peeters, J.; Dynesen, Jens Østergaard;

    2009-01-01

    of low oxygen availability, at different carbon source concentrations and at different specific growth rates, on the metabolism of A. niger, using continuous cultures. The results show that there is an increase in the production of tricarboxylic acid (TCA) cycle intermediates at low oxygen concentrations....... Indeed, at these conditions, a decrease in the mitochondrial respiratory chain activity leads to an accumulation of NADH and to a decreased ATP production which uncouples catabolism and anabolism, influences the intracellular pH and leads to production and excretion of organic acids. Moreover, mannitol...

  9. Source sector and region contributions to concentration and direct radiative forcing of black carbon in China

    Science.gov (United States)

    Li, Ke; Liao, Hong; Mao, Yuhao; Ridley, David A.

    2016-01-01

    We quantify the contributions from five domestic emission sectors (residential, industry, transportation, energy, and biomass burning) and emissions outside of China (non-China) to concentration and direct radiative forcing (DRF) of black carbon (BC) in China for year 2010 using a nested-grid version of the global chemical transport model (GEOS-Chem) coupled with a radiative transfer model. The Hemispheric Transport of Air Pollution (HTAP) anthropogenic emissions of BC for year 2010 are used in this study. Simulated surface-layer BC concentrations in China have strong seasonal variations, which exceed 9 μg m-3 in winter and are about 1-5 μg m-3 in summer in the North China Plain and the Sichuan Basin. Residential sector is simulated to have the largest contribution to surface BC concentrations, by 5-7 μg m-3 in winter and by 1-3 μg m-3 in summer, reflecting the large emissions from winter heating and the enhanced wet deposition during summer monsoon. The contribution from industry sector is the second largest and shows relatively small seasonal variations; the emissions from industry sector contribute 1-3 μg m-3 to BC concentrations in the North China Plain and the Sichuan Basin. The contribution from transportation sector is the third largest, followed by that from biomass burning and energy sectors. The non-China emissions mainly influence the surface-layer concentrations of BC in western China; about 70% of surface-layer BC concentration in the Tibet Plateau is attributed to transboundary transport. Averaged over all of China, the all-sky DRF of BC at the top of the atmosphere (TOA) is simulated to be 1.22 W m-2. Sensitivity simulations show that the TOA BC direct radiative forcings from the five domestic emission sectors of residential, industry, energy, transportation, biomass burning, and non-China emissions are 0.44, 0.27, 0.01, 0.12, 0.04, and 0.30 W m-2, respectively. The domestic and non-China emissions contribute 75% and 25% to BC DRF in China

  10. Comparation of Organic and Elemental carbon concentrations in PM2.5 in five Mexican cities: Potencial Sources

    Science.gov (United States)

    Herrera Murillo, J.; Cardenas, B.; Campos-Ramos, A.; Blanco-Jimenez, S.; Angeles-Garcia, F.

    2011-12-01

    During 2006-2010 the National Center for Environmental Research and Training of the National Institute of Ecology of Mexico, carried out several short field studies in the cities of Salamanca, Gto, Tula, Hgo; Guadalajara, Jal; Toluca, Edo Mex; and Tijuana, BC to determine concentration and chemical compositions of PM2.5. These cities, although different in size population have all important industrial and area sources that contribute to high PM2.5 concentrations and therefore potential health impacts. Chemical analyses included organic and elemental carbon for which DRI Model 2001 Thermal/Optical Carbon Analyzer (Atmoslytic Inc, Calabasas, CA, USA) was used. Highest PM2.5 mass mean concentrations were obtained in Salamanca (46 μg/m3), followed by Toluca (43 μg/m3), Guadalajara (37 μg/m3), Tula (20 μg/m3) and Tijuana (18 μg/m3). For Salamanca and Tula, annual levels exceeded the Mexican PM2.5 annual standard of 15 μg/m3. Total carbonaceous aerosol accounted for 41.4%, 41.1%, 32.3%, 29.5% and 29.1% of PM2.5 mass in Tula, Toluca, Guadalajara, Salamanca and Tijuana, respectively. Higher OC2, OC3 and OC4 carbon fractions were observed in Guadalajara, Tijuana and Toluca, indicating an important contribution of gasoline and diesel vehicles emissions in these cities. As for Tula and Salamanca, cities in which refineries and power plants are present, OC3, OC4, EC1 and EC2 represent the higher fractions which could be attributed to stationary sources that use heavy fuels for their combustion process. UNMIX and PMF analyses were used in order to identify the most important sources that contributes to OC and EC concentrations.

  11. Airborne black carbon concentrations over an urban region in western India-temporal variability, effects of meteorology, and source regions.

    Science.gov (United States)

    Bapna, Mukund; Sunder Raman, Ramya; Ramachandran, S; Rajesh, T A

    2013-03-01

    This study characterizes over 5 years of high time resolution (5 min), airborne black carbon (BC) concentrations (July 2003 to December 2008) measured over Ahmedabad, an urban region in western India. The data were used to obtain different time averages of BC concentrations, and these averages were then used to assess the diurnal, seasonal, and annual variability of BC over the study region. Assessment of diurnal variations revealed a strong association between BC concentrations and vehicular traffic. Peaks in BC concentration were co-incident with the morning (0730 to 0830, LST) and late evening (1930 to 2030, LST) rush hour traffic. Additionally, diurnal variability in BC concentrations during major festivals (Diwali and Dushera during the months of October/November) revealed an increase in BC concentrations due to fireworks displays. Maximum half hourly BC concentrations during the festival days were as high as 79.8 μg m(-3). However, the high concentrations rapidly decayed suggesting that local meteorology during the festive season was favorable for aerosol dispersion. A multiple linear regression (MLR) model with BC as the dependent variable and meteorological parameters as independent variables was fitted. The variability in temperature, humidity, wind speed, and wind direction accounted for about 49% of the variability in measured BC concentrations. Conditional probability function (CPF) analysis was used to identify the geographical location of local source regions contributing to the effective BC measured (at 880 nm) at the receptor site. The east north-east (ENE) direction to the receptor was identified as a major source region. National highway (NH8) and two coal-fired thermal power stations (at Gandhinagar and Sabarmati) were located in the identified direction, suggesting that local traffic and power plant emissions were likely contributors to the measured BC.

  12. Black carbon (BC) of urban topsoil of steel industrial city (Anshan), Northeastern China: Concentration, source identification and environmental implication.

    Science.gov (United States)

    Zong, Yutong; Xiao, Qing; Lu, Shenggao

    2016-11-01

    Black carbon (BC) and total carbon (TC) concentrations in urban topsoils and vertical profiles from steel industrial city, Anshan, Northeastern China, were determined. A total of 115 topsoil samples and 4 soil profiles were collected, in which the BC concentrations were determined using chemical oxidation technique. The BC concentrations in urban topsoils are in the range of 1.86 to 246.46gkg(-1) with an average of 33.86gkg(-1). Both BC and TC concentrations decrease sharply with soil depth, whereas BC/TC ratio shows a little variation with depth. The spatial distribution of BC in urban topsoils reveals that the BC concentration is much higher in the northern part of the city, which is consistent with the steel production. The distribution factors (DF) of BC are the highest in 1000-500 and 500-250μm size fractions, while the lowest in 50-2μm fraction. The mass loading of BC in 250-50 and 50-2μm size fractions accounts for 76.2% of bulk soil, indicating these two size fractions responsible for BC accumulation in soils. Enrichment factor (EF) of BC in urban topsoils ranges from 0.92 to 122.01 with an average of 16.76, indicating that the urban topsoils studied are moderately or severely accumulated by the BC. Strong correlation is found between BC and pollution load index (PLI) of heavy metals, indicating the possibility of similar sources of BC and heavy metals in soils. The BC/TC ratio in soils ranges from 0.45 to 0.97, with an average of 0.75. The BC/TC ratio shows the mixed sources of BC derived from fossil fuel combustion and vehicle emissions. The BC concentration and BC/TC ratio may reflect the degree of industrial activities and pollution sources in urban soils. The study demonstrated that BC is an effective indicator of degree and "hotspots" of heavy metals pollution in urban soils. PMID:27450257

  13. Black carbon concentrations and sources in the marine boundary layer of the tropical Atlantic Ocean using four methodologies

    Science.gov (United States)

    Pohl, K.; Cantwell, M.; Herckes, P.; Lohmann, R.

    2013-11-01

    Black carbon (BC) is the highly carbonaceous byproduct of biomass burning and fossil fuel combustion with a composition ranging from thermally stable soot to less recalcitrant charcoal. Atmospheric particulate matter samples across the tropical Atlantic Ocean were quantified for BC using four different methods: chemothermal oxidation at 375 °C (CTO-375), pyrene fluorescence loss, thermal optical transmittance, and optical transmission attenuation. The highest BC concentrations were detected in the Caribbean Sea and off the African coast, with a regional average of 0.6 μg m-3 for both. The lowest average concentrations were measured off the coast of South America at 0.2 to 0.3 μg m-3. The thermally-based CTO-375 method generally detected lower BC concentrations than the other three methods. The ratio of soot-like BC, as defined by the CTO-375 method, relative to the broader BC combustion continuum, as defined by the pyrene fluorescence loss, was <1 for all regions except for the Caribbean, supporting that charcoal was an important fraction of the aerosol BC. Regions impacted by biomass burning emissions should utilize multiple methods to better apportion the BC concentrations and sources.

  14. Variovorax sp.-mediated biodegradation of the phenyl urea herbicide linuron at micropollutant concentrations and effects of natural dissolved organic matter as supplementary carbon source

    OpenAIRE

    Horemans, Benjamin; Vandermaesen, Joke; Smolders, Erik; Springael, Dirk

    2013-01-01

    In nature, pesticides are often present as micropollutants with concentrations too low for efficient biodegradation and growth of heterotrophic pollutant degrading bacteria. Instead, organic carbon present in environmental dissolved organic matter (eDOM) constitutes the main carbon source in nature. Information on how natural organic carbon affects degradation of pollutants and micropollutants in particular, is however poor. Linuron degrading Variovorax sp. strains SRS16, WDL1 and PBLH6 and a...

  15. Denitrification of high concentrations of nitrites and nitrates in synthetic medium with different sources of organic carbon. III. Methanol.

    Science.gov (United States)

    Błaszczyk, M; Gałka, E; Sakowicz, E; Mycielski, R

    1985-01-01

    The denitrification of nitrites and nitrates (1000 mg N/l) in medium containing methanol as a source of organic carbon was studied. Continuous cultures of mixed population of autochtonic microflora from bottom sludge of nitrogenous wastewater reservoir were set up in a chemostat-type column and packed bed reactor. The efficiency of denitrification of nitrates in packed bed reactor was 506.7 mg N/l/h whereas denitrification of nitrites was from 8.7 to 16.0 mg N/l/h depending on the granulation of the filing material. In the latter case 83% nitrogen was removed from the medium. One of the factors causing low efficiency of denitrification of nitrites is excessive alkalization of the medium in the bed. The use of a three-step bed with adjusted pH resulted in complete denitrification of nitrites with efficiency 60 mg N/l/h. The bacteria inside the bed were dominated by Paracoccus denitrificans and by Pseudomonas aeruginosa when nitrates were present. The sensitivity of P. denitrificans to high concentrations of nitrites seems to be the second factor contributing to low efficiency of denitrification with methanol as organic substrate. PMID:2412408

  16. Source Material and Concentration of Wildfire-Produced Pyrogenic Carbon Influence Post-Fire Soil Nutrient Dynamics

    Directory of Open Access Journals (Sweden)

    Lucas A. Michelotti

    2015-04-01

    Full Text Available Pyrogenic carbon (PyC is produced by the thermal decomposition of organic matter in the absence of oxygen (O. PyC affects nutrient availability, may enhance post-fire nitrogen (N mineralization rates, and can be a significant carbon (C pool in fire-prone ecosystems. Our objectives were to characterize PyC produced by wildfires and examine the influence that contrasting types of PyC have on C and N mineralization rates. We determined C, N, O, and hydrogen (H concentrations and atomic ratios of charred bark (BK, charred pine cones (PC, and charred woody debris (WD using elemental analysis. We also incubated soil amended with BK, PC, and WD at two concentrations for 60 days to measure C and N mineralization rates. PC had greater H/C and O/C ratios than BK and WD, suggesting that PC may have a lesser aromatic component than BK and WD. C and N mineralization rates decreased with increasing PyC concentrations, and control samples produced more CO2 than soils amended with PyC. Soils with PC produced greater CO2 and had lower N mineralization rates than soils with BK or WD. These results demonstrate that PyC type and concentration have potential to impact nutrient dynamics and C flux to the atmosphere in post-fire forest soils.

  17. Polycyclic aromatic hydrocarbons and black carbon in intertidal sediments of China coastal zones: Concentration, ecological risk, source and their relationship.

    Science.gov (United States)

    Li, Xiaofei; Hou, Lijun; Li, Ye; Liu, Min; Lin, Xianbiao; Cheng, Lv

    2016-10-01

    Polycyclic aromatic hydrocarbons (PAHs) and black carbon (BC) have attracted many attentions, especially in the coastal environments. In this study, spatiotemporal distributions of PAHs and BC, and the correlations between BC and PAHs were investigated in the intertidal sediments of China coastal zones. BC in sediments was measured through dichromate oxidation (BCCr) and thermal oxidation (BCCTO). The concentrations of BCCr in the intertidal sediments ranged between 0.61 and 6.32mgg(-1), while BCCTO ranged between 0.57 and 4.76mgg(-1). Spatial variations of δ(13)C signatures in TOC and BC were observed, varying from -21.13‰ to -24.87‰ and from -23.53‰ to -16.78‰, respectively. PAH contents of sediments ranged from 195.9 to 4610.2ngg(-1) in winter and 98.2 to 2796.5ngg(-1) in summer, and significantly seasonal variations were observed at most sampling sites. However, the results of potential toxicity assessment indicated low ecological risk in the intertidal sediments of China coastal zones. Greater concentrations of PAHs measured in the sediments of estuarine environments indicated that rivers runoff may have been responsible for the higher PAH pollution levels in the intertidal sediments of China coastal zones. Pearson's correlation analysis suggested that pyrogenic compounds of PAH were significantly related to BC, due to that both BC and these compounds derived mainly from the combustion process of fossil fuels and biomass. Overall, increasing energy consumptions caused by anthropogenic activities can contribute more emissions of BC as well as PAHs and thus improve the importance of BC in indicating pyrogenic compounds of PAHs in the intertidal sediments of China coastal zones. PMID:27266522

  18. KOMBUCHA DENGAN VARIASI KADAR GULA KELAPA SEBAGAI SUMBER KARBON [Kombucha from Different Coconut Sugar Concentration as a Carbon Source

    Directory of Open Access Journals (Sweden)

    Merkuria Karyantina

    2008-12-01

    Full Text Available Kombucha has been known as traditional medicine that can cure various diseases, such as hypercholesterol. Kombucha made of fermented sweetened tea using symbiotic growth of khamir and bacteria. Functional properties of kombucha related to metabolite that has been produced during fermentation process, glucuronic acid. The aim of this research was to get a fit carbon source that can produce kombucha which have highest glucuronic acid. The result showed that microbe that dominated at the beginning through the end of fermentation process was a group of khamir, i.e 1.81x107 ; 1.43x106 ; 2.40x107 ; 7.00x104 CFU/mL for 1, 4, 7, and 10% of additive coconut sugar. Kombucha at 4% of coconut sugar yielded 8.86 ppm of glucuronic acid. Meanwhile, kombucha with 10% of coconut sugar yielded 6.22 ppm of glucuronic acid. Total acid has no corelation with glucuronid acid formation during the fermentation process.

  19. Quantifying sediment source contributions in coastal catchments impacted by the Fukushima nuclear accident with carbon and nitrogen elemental concentrations and stable isotope ratios

    Science.gov (United States)

    Laceby, J. Patrick; Huon Huon, Sylvain; Onda, Yuichi; Evrard, Olivier

    2016-04-01

    The Fukushima Dai-ichi Nuclear Power Plant accidental release of radioactive contaminants resulted in the significant fallout of radiocesium over several coastal catchments in the Fukushima Prefecture. Radiocesium, considered to be the greatest risk to the short and long term health of the local community, is rapidly bound to fine soil particles and thus is mobilized and transported during soil erosion and runoff processes. As there has been a broad-scale decontamination of rice paddy fields and rural residential areas in the contaminated region, one important long term question is whether there is, or may be, a downstream transfer of radiocesium from forests that covered over 65% of the most contaminated region. Accordingly, carbon and nitrogen elemental concentrations and stable isotope ratios are used to determine the relative contributions of forests and rice paddies to transported sediment in three contaminated coastal catchments. Samples were taken from the three main identified sources: cultivated soils (rice paddies and fields, n=30), forest soils (n=45), and subsoils (channel bank and decontaminated soils, n = 25). Lag deposit sediment samples were obtained from five sampling campaigns that targeted the main hydrological events from October 2011 to October 2014. In total, 86 samples of deposited sediment were analyzed for particulate organic matter elemental concentrations and isotope ratios, 24 from the Mano catchment, 44 from the Niida catchment, and 18 from the Ota catchment. Mann-Whitney U-tests were used to examine the source discrimination potential of this tracing suite and select the appropriate tracers for modelling. The discriminant tracers were modelled with a concentration-dependent distribution mixing model. Preliminary results indicate that cultivated sources (predominantly rice paddies) contribute disproportionately more sediment per unit area than forested regions in these contaminated catchments. Future research will examine if there are

  20. Comment on: "Possible source of ancient carbon in phytolith concentrates from harvested grasses" by G. M. Santos et al. (2012

    Directory of Open Access Journals (Sweden)

    L. A. Sullivan

    2012-10-01

    Full Text Available Santos et al. (2012 address the important issue that 14C dating of the carbon occluded in silica phytoliths (PhytOC isolated from contemporary plant materials can produce ages that are incompatible, being often several kyr older, with both their known recent origin and the 14C age of the bulk plant material. In their article, Santos et al. (2012 propose that the anomalously old 14C carbon dates of PhytOC from harvested plant materials are based on plants taking up "old" dissolved soil carbon to the plant by roots during nutrient uptake. They then propose that this old soil-derived carbon is subsequently partitioned from the general plant biomass into either the silica phytoliths they produce, or as recalcitrant organic matter elsewhere in the plant. We suggest that the full data available for PhytOC 14C dating does not support this hypothesis. Santos et al. (2012 also address the important issue of contamination of PhytOC by general plant biomass material that can occur with procedures that incompletely extract phytoliths. Whilst we agree that such contamination needs to be avoided when examining the nature of PhytOC, we also point out that the converse problem, i.e. removal of PhytOC by over-vigorous extraction procedures, can also have important adverse consequences.

  1. Comment on "Possible source of ancient carbon in phytolith concentrates from harvested grasses" by G. M. Santos et al. (2012

    Directory of Open Access Journals (Sweden)

    L. A. Sullivan

    2013-02-01

    Full Text Available Santos et al. (2012 address the important issue that 14C dating of the carbon occluded in silica phytoliths (PhytOC isolated from contemporary plant materials can produce ages that are incompatible, being often several kyr older, with both their known recent origin and the 14C age of the bulk plant material. In their article, Santos et al. (2012 propose that the anomalously old 14C carbon dates of PhytOC from harvested plant materials are based on plants taking up "old" dissolved soil carbon to the plant by roots during nutrient uptake. They then propose that this old soil-derived carbon is subsequently partitioned from the general plant biomass into either the silica phytoliths they produce or as recalcitrant organic matter elsewhere in the plant. We suggest that the full data available for PhytOC 14C dating do not support this hypothesis. Santos et al. (2012 also address the important issue of contamination of PhytOC by general plant biomass material that can occur with procedures that incompletely extract phytoliths. Whilst we agree that such contamination needs to be avoided when examining the nature of PhytOC, we also point out that the converse problem, i.e. removal of PhytOC by over-vigorous extraction procedures, can also have important adverse consequences.

  2. Comparison of Spheroidal Carbonaceous Particle Data with Modelled Atmospheric Black Carbon Concentration and Deposition and Air Mass Sources in Northern Europe, 1850–2010

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    Meri Ruppel

    2013-01-01

    Full Text Available Spheroidal carbonaceous particles (SCP are a well-defined fraction of black carbon (BC, produced only by the incomplete combustion of fossil fuels such as coal and oil. Their past concentrations have been studied using environmental archives, but, additionally, historical trends of BC concentration and deposition can be estimated by modelling. These models are based on BC emission inventories, but actual measurements of BC concentration and deposition play an essential role in their evaluation and validation. We use the chemistry transport model OsloCTM2 to model historical time series of BC concentration and deposition from energy and industrial sources and compare these to sedimentary measurements of SCPs obtained from lake sediments in Northern Europe from 1850 to 2010. To determine the origin of SCPs we generated back trajectories of air masses to the study sites. Generally, trends of SCP deposition and modelled results agree reasonably well, showing rapidly increasing values from 1950, to a peak in 1980, and a decrease towards the present. Empirical SCP data show differences in deposition magnitude between the sites that are not captured by the model but which may be explained by different air mass transport patterns. The results highlight the need for numerous observational records to reliably validate model results.

  3. Effect of various sources of organic carbon and high nitrite and nitrate concentrations on the selection of denitrifying bacteria. II. Continuous cultures in packed bed reactors.

    Science.gov (United States)

    Błaszczyk, M

    1983-01-01

    The effect of different organic compounds, nitrites and nitrates at the concentration of 1,000 mg N/l on the quantitative and strain-specific selection of denitrifying bacteria was determined in anaerobic packed bed reactors. Both the source of carbon and nitrogen form influenced strain specificity and the frequency of occurrence of denitrifying bacteria. The frequency of denitrifying bacteria within packed bed reactor ranged in different media from 11% (glucose and nitrates) to 100% (methanol and ethanol with nitrates). A single species selection was observed in the presence of nitrites within packed bed reactor: Pseudomonas aeruginosa in medium with acetate. Pseudomonas stutzeri in medium with ethanol, Pseudomonas mendocina in medium with methanol and Pseudomonas fluorescens in medium with glucose. When nitrates were present in packed bed reactor, the dominating bacteria were: P. stutzeri in medium with acetate, P. fluorescens in medium with ethanol, Paracoccus denitrificans in medium with methanol and Alcaligenes faecalis in medium with glucose. PMID:6194668

  4. Effect of carbon source on acclimatization of nitrifying bacteria to achieve high-rate partial nitrification of wastewater with high ammonium concentration

    Science.gov (United States)

    Mousavi, Seyyed Alireza; Ibrahim, Shaliza; Aroua, Mohamed Kheireddine

    2014-08-01

    Experiments in two laboratory-scale sequential batch reactors were carried out to investigate the effect of heterotrophic bacteria on nitrifying bacteria using external carbon sources. Partial nitrification of ammonium-rich wastewater during short-term acclimatization enriched the activity of ammonia-oxidizing bacteria in both reactors. Heterotrophic bacteria exhibited a minor effect on nitrifying bacteria, and complete removal of ammonium occurred at a rate of 41 mg L-1 h-1 in both reactors. The main strategy of this research was to carry out partial nitrification using high-activity ammonia-oxidizing bacteria with a high concentration of free ammonia (70 mg L-1). The NO2 -/(NO3 - + NO2 -) ratio was greater than 0.9 in both reactors most of the time.

  5. Long-Term Observations on Aerosol Elemental Carbon and Mass Concentrations in Winter-Time in New Delhi: Implications for Local Source Changes

    Science.gov (United States)

    Aggarwal, S. G.; Singh, K.; Singh, N.; Gupta, P. K.

    2009-12-01

    Fossil-fuel and bio-fuel burning are the two major sources identified for high carbonaceous aerosol loadings in several mega cities in India. In the last decade, according to a report from the Central Pollution Control Board (CPCB, 1999), the vehicular emission (mostly diesel-powered engines) was contributed to ~67% of the total air pollution load in New Delhi. Therefore, a policy decision was taken by the government, and most of the diesel-powered engines were converted to compressed natural gas (CNG) -powered engines by 2003. To better understand the effect of these changes on air quality, we collected high volume aerosol samples (total suspended particles, TSP) mostly for a day basis at our institute building in New Delhi almost everyday during winter season (November to January) from 2002 to 2008. We found very high mean aerosol loading, i.e., 488±47 μg m-3 in 2002 winter, which dropped significantly to 280±73 μg m-3 in 2003 winter. Thereafter, a steadily increased trend of aerosol mass loadings was observed, i.e., 339±112, 339±120, 412±107 and 444±55 μg m-3 in 2004, 2005, 2006 and 2007 winters, respectively. Similar trend was also observed for elemental carbon (EC) concentration in TSP, which was peaked in 2002 (47±11 μg m-3) and minimized in 2003 (32±6 μg m-3), and then gradually increased to 41±8 μg m-3 in 2007 winter. These decline trends of aerosol mass and EC concentrations in 2003 can be explained well, because of the conversion of diesel engine to CNG engines of public transport facilities. However, again increase in aerosol mass and EC concentrations possibly because of a high increase in road traffic in recent years. According to the economic survey of New Delhi 2008-09, the number of vehicles (which includes all types of engines, i.e., petrol, diesel and CNG) has grown from ~3.3 millions in 1997-98 to ~5.6 millions in 2007-08. The influence of engine types and vehicle population on aerosol loading can also be explained well by SO2 and

  6. Bioethanol from different Finnish agricultural carbon sources

    Energy Technology Data Exchange (ETDEWEB)

    Kautola, H.; Kymaelaeinen, M.; Tokeensuu, L.; Alatalo, T. (HAMK University of Applied Sciences, Degree Programme in Biotechnology and Food Engineering, Haemeenlinna (Finland)); Caerdenas, R. (Universidad Central del Ecuador, Facultad Ciencias Quimicas, Escuela de Quimica, Av. America. Ciudadela Universitaria, Quito (Ecuador)); Siukola, K.; Naesi, J. (Suomen Biojalostus Oy, Renko (Finland))

    2007-07-01

    Bioethanol in fuel and its domestic production has become a great issue in Finland during the last few years. There has been discussion about what kind of raw materials should be used and are there any local priorities. In the years 2004-2007 local farmers in Haem e , in southern part of Finland, started to find alternative use for sugar beet due to drastic reduction of domestic sugar production in the near future. This was also the start of the experimental studies on bi oethanol production. The aim of the study was to find out how the change of carbon source will effect on bi oethanol yield. The bioethanol production was studied in laboratory scale using carbon sources of saccharose, glucose, sugar beet juice, sugar beet mash and barley hydrolysates pretreated with amylases, (beta-glucanase and xylanase). The yeast used was Saccharomyces sp. The pre experiments were performed in 250 mL flasks to optimize carbon, nitrogen and salts contents in production medium, also comparing different carbon sources and mixtures. The production was then studied in a 30 liter fermenter running for 36 hours. The preliminary studies showed that barley hydrolysate gave the best result 2,4% in bioethanol concentration during the performed fermentations, and saccharose was the best substrate in shake flask fermentations with a 9,6% bioethanol concentration. (orig.)

  7. Revealing source signatures in ambient BTEX concentrations

    International Nuclear Information System (INIS)

    Management of ambient concentrations of Volatile Organic Compounds (VOCs) is essential for maintaining low ozone levels in urban areas where its formation is under a VOC-limited regime. The significant decrease in traffic-induced VOC emissions in many developed countries resulted in relatively comparable shares of traffic and non-traffic VOC emissions in urban airsheds. A key step for urban air quality management is allocating ambient VOC concentrations to their pertinent sources. This study presents an approach that can aid in identifying sources that contribute to observed BTEX concentrations in areas characterized by low BTEX concentrations, where traditional source apportionment techniques are not useful. Analysis of seasonal and diurnal variations of ambient BTEX concentrations from two monitoring stations located in distinct areas reveal the possibility to identify source categories. Specifically, the varying oxidation rates of airborne BTEX compounds are used to allocate contributions of traffic emissions and evaporative sources to observed BTEX concentrations. - BTEX sources are identified from temporal variations of ambient concentration

  8. Radiation tolerance of Si{sub 1−y}C{sub y} source/drain n-type metal oxide semiconductor field effect transistors with different carbon concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Nakashima, Toshiyuki, E-mail: nakashima_t@cdk.co.jp [Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki (Japan); Chuo Denshi Kogyo Co., Ltd., 3400 Kohoyama, Matsubase, Uki, Kumamoto (Japan); Asai, Yuki; Hori, Masato; Yoneoka, Masashi; Tsunoda, Isao; Takakura, Kenichiro [Kumamoto National College of Technology, 2659-2 Suya, Koshi, Kumamoto 861-1102 (Japan); Gonzalez, Mireia Bargallo [Institut de Microelectronica de Barcelona (Centre Nacional de Microelectronica — Consejo Superior de Investigaciones Cientificas) Campus UAB, 08193 Bellaterra (Spain); Simoen, Eddy [imec, Kapeldreef 75, B-3001 Leuven (Belgium); Claeys, Cor [imec, Kapeldreef 75, B-3001 Leuven (Belgium); Department of Electrical Engineering, KU Leuven, Kasteelpark Arenberg 10, B-3001 Leuven (Belgium); Yoshino, Kenji [Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki (Japan)

    2014-04-30

    The 2-MeV electron radiation damage of silicon–carbon source/drain (S/D) n-type metal oxide semiconductor field effect transistors with different carbon (C) concentrations is studied. Before irradiation, an enhancement of the electron mobility with C concentration of the S/D stressors is clearly observed. On the other hand, after electron irradiation, both the threshold voltage shift and the maximum electron mobility degradation are independent on the C concentration for all electron fluences studied. These results indicate that the strain induced electron mobility enhancement due to the C doping is retained after irradiation in the studied devices. - Highlights: • We have investigated the electron irradiation effect of the Si{sub 1−y}C{sub y} S/D n-MOSFETs. • The threshold voltage variations by irradiation are independent on the C doping. • The electron-mobility decreased for all C concentrations by electron irradiation. • The strain induced mobility enhancement effect is retained after irradiation.

  9. Mesoscale inversion of carbon sources and sinks

    International Nuclear Information System (INIS)

    Inverse methods at large scales are used to infer the spatial variability of carbon sources and sinks over the continents but their uncertainties remain large. Atmospheric concentrations integrate the surface flux variability but atmospheric transport models at low resolution are not able to simulate properly the local atmospheric dynamics at the measurement sites. However, the inverse estimates are more representative of the large spatial heterogeneity of the ecosystems compared to direct flux measurements. Top-down and bottom-up methods that aim at quantifying the carbon exchanges between the surface and the atmosphere correspond to different scales and are not easily comparable. During this phD, a mesoscale inverse system was developed to correct carbon fluxes at 8 km resolution. The high resolution transport model MesoNH was used to simulate accurately the variability of the atmospheric concentrations, which allowed us to reduce the uncertainty of the retrieved fluxes. All the measurements used here were observed during the intensive regional campaign CERES of May and June 2005, during which several instrumented towers measured CO2 concentrations and fluxes in the South West of France. Airborne measurements allowed us to observe concentrations at high altitude but also CO2 surface fluxes over large parts of the domain. First, the capacity of the inverse system to correct the CO2 fluxes was estimated using pseudo-data experiments. The largest fraction of the concentration variability was attributed to regional surface fluxes over an area of about 300 km around the site locations depending on the meteorological conditions. Second, an ensemble of simulations allowed us to define the spatial and temporal structures of the transport errors. Finally, the inverse fluxes at 8 km resolution were compared to direct flux measurements. The inverse system has been validated in space and time and showed an improvement of the first guess fluxes from a vegetation model

  10. Effect of carbon source concentration and culture duration on retreivability of bacteria from certain estuarine, coastal and offshore areas around the peninsular India.

    Digital Repository Service at National Institute of Oceanography (India)

    Goltekar, R.C.; Krishnan, K.P.; DeSouza, M.J.B.D.; Paropkari, A.L.; LokaBharathi, P.A.

    ) and retrievable plate counts as colony forming units (CFU). Retrievability was improved by decreasing nutrient concentration in the culture medium. Maximum retrievability of 10^4 CFU ml^–1 was obtained on 0.1% nutrient strength (100% corresponds to 8 g l^–1...

  11. High Black Carbon (BC) Concentrations along Indian National Highways

    Science.gov (United States)

    Kumar, S.; Singh, A. K.; Singh, R. P.

    2015-12-01

    Abstract:Black carbon (BC), the optically absorbing component of carbonaceous aerosol, has direct influence on radiation budget and global warming. Vehicular pollution is one of the main sources for poor air quality and also atmospheric pollution. The number of diesel vehicles has increased on the Indian National Highways during day and night; these vehicles are used for the transport of goods from one city to another city and also used for public transport. A smoke plume from the vehicles is a common feature on the highways. We have made measurements of BC mass concentrations along the Indian National Highways using a potable Aethalometer installed in a moving car. We have carried out measurements along Varanasi to Kanpur (NH-2), Varanasi to Durgapur (NH-2), Varanasi to Singrauli (SH-5A) and Varanasi to Ghazipur (NH-29). We have found high concentration of BC along highways, the average BC mass concentrations vary in the range 20 - 40 µg/m3 and found high BC mass concentrations up to 600 μg/m3. Along the highways high BC concentrations were characteristics of the presence of industrial area, power plants, brick kilns and slow or standing vehicles. The effect of increasing BC concentrations along the National Highways and its impact on the vegetation and human health will be presented. Key Words: Black Carbon; Aethalometer; mass concentration; Indian National Highways.

  12. Hydrologic significance of carbon monoxide concentrations in ground water

    Science.gov (United States)

    Chapelle, F.H.; Bradley, P.M.

    2007-01-01

    Dissolved carbon monoxide (CO) is present in ground water produced from a variety of aquifer systems at concentrations ranging from 0.2 to 20 nanomoles per liter (0.0056 to 0.56 ??g/L). In two shallow aquifers, one an unconsolidated coastal plain aquifer in Kings Bay, Georgia, and the other a fractured-bedrock aquifer in West Trenton, New Jersey, long-term monitoring showed that CO concentrations varied over time by as much as a factor of 10. Field and laboratory evidence suggests that the delivery of dissolved oxygen to the soil zone and underlying aquifers by periodic recharge events stimulates oxic metabolism and produces transiently high CO concentrations. In between recharge events, the aquifers become anoxic and more substrate limited, CO is consumed as a carbon source, and CO concentrations decrease. According to this model, CO concentrations provide a transient record of oxic metabolism affecting ground water systems after dissolved oxygen has been fully consumed. Because the delivery of oxygen affects the fate and transport of natural and anthropogenic contaminants in ground water, CO concentration changes may be useful for identifying predominantly anoxic ground water systems subject to periodic oxic or microaerophilic conditions. ?? 2007 National Ground Water Association.

  13. Effect of carbon dioxide concentration on the bioleaching of a pyrite-arsenopyrite ore concentrate

    Energy Technology Data Exchange (ETDEWEB)

    Nagpal, S.; Dahlstrom, D. (Univ. of Utah, Salt Lake City (United States)); Oolman, T. (Radian Corp., Austin, TX (United States))

    1993-02-20

    The effect of carbon dioxide concentration on the bacterial leaching of a pyrite-arsenopyrite ore concentrate was studied in continuous-flow reactors. Steady-state operation with two feed slurry densities, 6 wt% and 16wt% solids, were tested for the effect of carbon dioxide concentration. Bacterial growth rates were estimated via the measurement of carbon dioxide consumption rates. Aqueous-phase carbon dioxide concentrations in excess of 10 mg/L were found to be inhibitory to bacterial growth.

  14. The Carbon-Nitrogen Balance of the Nodule and Its Regulation under Elevated Carbon Dioxide Concentration

    Directory of Open Access Journals (Sweden)

    Marc Libault

    2014-01-01

    Full Text Available Legumes have developed a unique way to interact with bacteria: in addition to preventing infection from pathogenic bacteria like any other plant, legumes also developed a mutualistic symbiotic relationship with one gender of soil bacteria: rhizobium. This interaction leads to the development of a new root organ, the nodule, where the differentiated bacteria fix for the plant the atmospheric dinitrogen (atmN2. In exchange, the symbiont will benefit from a permanent source of carbon compounds, products of the photosynthesis. The substantial amounts of fixed carbon dioxide dedicated to the symbiont imposed to the plant a tight regulation of the nodulation process to balance carbon and nitrogen incomes and outcomes. Climate change including the increase of the concentration of the atmospheric carbon dioxide is going to modify the rates of plant photosynthesis, the balance between nitrogen and carbon, and, as a consequence, the regulatory mechanisms of the nodulation process. This review focuses on the regulatory mechanisms controlling carbon/nitrogen balances in the context of legume nodulation and discusses how the change in atmospheric carbon dioxide concentration could affect nodulation efficiency.

  15. Atmospheric black carbon and sulfate concentrations in Northeast Greenland

    Directory of Open Access Journals (Sweden)

    A. Massling

    2015-04-01

    Full Text Available Measurements of Black Carbon (BC in aerosols at the high Arctic field site Villum Research Station (VRS at Station Nord in North Greenland showed a seasonal variation in BC concentrations with a maximum in winter and spring at ground level. The data was obtained using a Multi Angle Absorption Photometer (MAAP. A similar seasonal pattern was found for sulfate concentrations with a maximum level during winter and spring analyzed by ion chromatography. A correlation between BC and sulfate concentrations was observed over the years 2011 to 2013. This finding gives the hint that most likely transport of primary emitted BC particles to the Arctic was accompanied by aging of the aerosols through condensational processes. This process may have led to the formation of secondary inorganic matter and further transport of BC particles as cloud processing and further washout of particles is less likely based on the typically observed transport patterns of air masses arriving at VRS. Additionally, concentrations of EC (elemental carbon based on a thermo-optical method were determined and compared to BC measurements. Model estimates of the climate forcing due to BC in the Arctic are based on contributions of long-range transported BC during spring and summer. The measured concentrations were here compared with model results obtained by the Danish Hemispheric Model, DEHM. Good agreement between measured and modeled concentrations of both BC and sulfate was observed. The dominant source is found to be combustion of fossil fuel with biomass burning as a minor though significant source. During winter and spring the Arctic atmosphere is known to be impacted by long-range transport of BC and associated with the Arctic haze phenomenon.

  16. Atmospheric black carbon and sulfate concentrations in Northeast Greenland

    Science.gov (United States)

    Massling, A.; Nielsen, I. E.; Kristensen, D.; Christensen, J. H.; Sørensen, L. L.; Jensen, B.; Nguyen, Q. T.; Nøjgaard, J. K.; Glasius, M.; Skov, H.

    2015-08-01

    Measurements of equivalent black carbon (EBC) in aerosols at the high Arctic field site Villum Research Station (VRS) at Station Nord in North Greenland showed a seasonal variation in EBC concentrations with a maximum in winter and spring at ground level. Average measured concentrations were about 0.067 ± 0.071 for the winter and 0.011 ± 0.009 for the summer period. These data were obtained using a multi-angle absorption photometer (MAAP). A similar seasonal pattern was found for sulfate concentrations with a maximum level during winter and spring analyzed by ion chromatography. Here, measured average concentrations were about 0.485 ± 0.397 for the winter and 0.112 ± 0.072 for the summer period. A correlation between EBC and sulfate concentrations was observed over the years 2011 to 2013 stating a correlation coefficient of R2 = 0.72. This finding gives the hint that most likely transport of primary emitted BC particles to the Arctic was accompanied by aging of the aerosols through condensational processes. BC and sulfate are known to have only partly similar sources with respect to their transport pathways when reaching the high Arctic. Aging processes may have led to the formation of secondary inorganic matter and further transport of BC particles as cloud processing and further washout of particles is less likely based on the typically observed transport patterns of air masses arriving at VRS. Additionally, concentrations of EC (elemental carbon) based on a thermo-optical method were determined and compared to EBC measurements. EBC measurements were generally higher, but a correlation between EC and EBC resulted in a correlation coefficient of R2 = 0.64. Model estimates of the climate forcing due to BC in the Arctic are based on contributions of long-range transported BC during spring and summer. The measured concentrations were here compared with model results obtained by the Danish Eulerian Hemispheric Model, DEHM. Good agreement between measured and

  17. Origin of black carbon concentration peaks in Cairo (Egypt)

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoud, K.F.; Wahab, M.M.A. [Cairo Univ, Fac Sci, Astron and Meteorol Dept, Giza (Egypt); Alfaro, S.C. [Univ Paris 12, LISA, F-94010 Creteil, (France); Alfaro, S.C. [Univ Paris 07, CNRS, F-94010 Creteil (France); Favez, O.; Sciare, J. [CEA Saclay, DSM, LSCE IPSL, Lab mixte CEA-CNRS-UVSQ, F-91191 Gif Sur Yvette (France)

    2008-07-01

    The concentration in black carbon (BC) has been monitored in the mega-city of Cairo (Egypt) during the autumn 2004 and spring 2005 intensive observation periods of the Cairo Aerosol Characterization Experiment (CACHE). As expected for a species released by human activities, hourly mean of this concentration is found to be large at all times. It is also significantly larger in autumn than in spring (9.9 {+-} 6.6 and 6.9 {+-} 4.8 {mu}gC/m{sup 3}, respectively) and quite variable at shorter (diurnal) time scales. Indeed, sharp concentration peaks larger than 25 {mu}gC/m{sup 3} are frequently detected during both observation periods. In order to apportion the roles played by emission intensity and meteorological conditions in the development of these peaks, a simple model is developed that allows derivation of the hourly mean BC emissions by the part of town located upwind of the measurement site. The analysis of the time dependence of these emissions indicates that traffic is by far the major source of BC in Cairo during daytime and this even in autumn when biomass burning takes place in the Nile delta. It is only between 03:00 and 05:00 in the night, at a time when traffic emissions are quite reduced, that the influence of this particular source on BC concentration can become significant. This study also indicates that BC emissions by motorized traffic remain important from the morning rush hour until late in the night. During the day, and particularly in spring, the dilution effect resulting from the development of the planetary boundary layer prevents BC concentrations from becoming very large. This is no longer the case just before sunrise and after sunset, when the combination of dense traffic and low boundary layer is responsible for the observed sharp increase in BC concentration. (authors)

  18. Variability in Carbon Monoxide Concentration in Kaduna Metropolis, Nigeria

    Directory of Open Access Journals (Sweden)

    J.D. Ariko

    2014-04-01

    Full Text Available This study compared Carbon Monoxide concentrations in Urban core and Control station in Kaduna Metropolis, Nigeria. USB-CO data loggers were used for data acquisition for a period of one month. 1hour mean of Carbon Monoxide concentrations for Urban core and Control station were subjected to student “t” test to determine any significant difference in Carbon Monoxide concentration between the two sampled sites. Analysis of Variance (ANOVA test was employed to test the temporal variability in Carbon Monoxide concentrations in the Urban core. The “t” test results showed a significant difference in Carbon Monoxide concentrations, between the Urban core and the Control station. The ANOVA results showed that there is a significant difference in Carbon Monoxide concentrations level between different times of the day. The 1 h mean WHO recommendation for Carbon Monoxide concentration was occasionally exceeded, while the 8 h mean was daily exceeded in the evening periods in Urban core. In the Control station, there was no time both 1 h and 8 h means WHO recommendation were exceeded. These imply that the Rural environment is relatively more livable than the Urban environment in Kaduna metropolis in terms of Carbon Monoxide concentration levels.

  19. Changes in plasma potassium concentration during carbon dioxide pneumoperitoneum

    DEFF Research Database (Denmark)

    Perner, A; Bugge, K; Lyng, K M;

    1999-01-01

    Hyperkalaemia with ECG changes had been noted during prolonged carbon dioxide pneumoperitoneum in pigs. We have compared plasma potassium concentrations during surgery in 11 patients allocated randomly to undergo either laparoscopic or open appendectomy and in another 17 patients allocated randomly...... to either carbon dioxide pneumoperitoneum or abdominal wall lifting for laparoscopic colectomy. Despite an increasing metabolic acidosis, prolonged carbon dioxide pneumoperitoneum resulted in only a slight increase in plasma potassium concentrations, which was both statistically and clinically insignificant...

  20. 青藏高原冰川区可溶性有机碳含量和来源研究%Concentration and Source of Dissolved Organic Carbon in Snowpits of the Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    严芳萍; 康世昌; 陈鹏飞; 柏建坤; 李洋; 胡召富; 李潮流

    2015-01-01

    Snowpit samples of three glaciers ( Laohugou NO. 12 Glacier ( LHG), Small Dongkemadi Glacier on Mount Tanggula (TGL) and East Rongbuk Glacier on Mount Everest (ZF)) in the Tibetan Plateau were collected. Concentrations of DOC and major ions were analyzed. The results showed that average DOC concentrations of the snowpits of LHG, TGL and ZF were (250. 30 ± 157. 10), (216. 92 ± 142. 82) and (152. 50 ± 56. 11) μg·L - 1 , respectively. DOC of TGL and ZF accounted for large parts of total values of DOC and ions. Correspondingly, DOC of LHG accounted for small part (only 5% ), because LHG was located at north China and intensively influenced by natural mineral dust, which caused high concentrations of Ca2 + (the highest value could reach 5 299. 18μg·L - 1 ) and consequently low percentage of DOC of snowpit samples. Correlation and PCA analyses were used to study the sources of DOC. DOC was significantly correlated with Ca2 + , Mg2 + , K + and SO2 -4 . Additionally, PCA further indicated that the main potential source of DOC was the natural source of mineral dust. Meanwhile, anthropogenic pollutants ( e. g. biomass, fossil combustion and agricultural related pollutants) could also not be ignored. Moreover, the carbon depositional fluxes of three snowpits were roughly estimated, and the values of LHG, TGL and ZF snowpits were 189. 23, 132. 76 and 128. 44 mg·(m2·a) - 1 , respectively, which played a significant role in the carbon cycle in this region and was also helpful for the study of glaciers fluctuation.%对青藏高原祁连山老虎沟12号冰川、唐古拉山小冬克玛底冰川及珠穆朗玛峰北坡东绒布冰川雪坑样品中可溶性有机碳(DOC)和主要离子的质量浓度进行了分析.结果表明3个雪坑中 DOC 的平均质量浓度分别为(250.30±157.10)、(216.92±142.82)和(152.50±56.11)μg·L -1,具有从北到南依次减小的空间分布特点.3个雪坑 DOC 和主要离子质量浓度比例分析表明,唐古拉山冰川区和

  1. Corals concentrate dissolved inorganic carbon to facilitate calcification.

    Science.gov (United States)

    Allison, Nicola; Cohen, Itay; Finch, Adrian A; Erez, Jonathan; Tudhope, Alexander W

    2014-01-01

    The sources of dissolved inorganic carbon (DIC) used to produce scleractinian coral skeletons are not understood. Yet this knowledge is essential for understanding coral biomineralization and assessing the potential impacts of ocean acidification on coral reefs. Here we use skeletal boron geochemistry to reconstruct the DIC chemistry of the fluid used for coral calcification. We show that corals concentrate DIC at the calcification site substantially above seawater values and that bicarbonate contributes a significant amount of the DIC pool used to build the skeleton. Corals actively increase the pH of the calcification fluid, decreasing the proportion of DIC present as CO2 and creating a diffusion gradient favouring the transport of molecular CO2 from the overlying coral tissue into the calcification site. Coupling the increases in calcification fluid pH and [DIC] yields high calcification fluid [CO3(2-)] and induces high aragonite saturation states, favourable to the precipitation of the skeleton.

  2. Black carbon concentrations and mixing state in the Finnish Arctic

    Science.gov (United States)

    Raatikainen, T.; Brus, D.; Hyvärinen, A.-P.; Svensson, J.; Asmi, E.; Lihavainen, H.

    2015-09-01

    Atmospheric aerosol composition was measured using a Single Particle Soot Photometer (SP2) in the Finnish Arctic during winter 2011-2012. The Sammaltunturi measurement site at the Pallas GAW (Global Atmosphere Watch) station receives air masses from different source regions including the Arctic Ocean and continental Europe. The SP2 provides detailed information about mass distributions and mixing state of refractory black carbon (rBC). The measurements showed widely varying rBC mass concentrations (0-120 ng m-3), which were related to varying contributions of different source regions and aerosol removal processes. The rBC mass was log-normally distributed showing a relatively constant rBC core mass mean diameter with an average of 194 nm (75-655 nm sizing range). On average, the number fraction of particles containing rBC was 0.24 (integrated over 350-450 nm particle diameter range) and the average particle diameter to rBC core volume equivalent diameter ratio was 2.0 (averaged over particles with 150-200 nm rBC core volume equivalent diameters). These average numbers mean that the observed rBC core mass mean diameter is similar to those of aged particles, but the observed particles seem to have unusually high particle to rBC core diameter ratios. Comparison of the measured rBC mass concentration with that of the optically detected equivalent black carbon (eBC) using an Aethalometer and a MAAP showed that eBC was larger by a factor of five. The difference could not be fully explained without assuming that only a part of the optically detected light absorbing material is refractory and absorbs light at the wavelength used by the SP2. Finally, climate implications of five different black carbon mixing state representations were compared using the Mie approximation and simple direct radiative forcing efficiency calculations. These calculations showed that the observed mixing state means significantly lower warming effect or even a net cooling effect when compared with

  3. Changes in plasma potassium concentration during carbon dioxide pneumoperitoneum

    DEFF Research Database (Denmark)

    Perner, A; Bugge, K; Lyng, K M;

    1999-01-01

    Hyperkalaemia with ECG changes had been noted during prolonged carbon dioxide pneumoperitoneum in pigs. We have compared plasma potassium concentrations during surgery in 11 patients allocated randomly to undergo either laparoscopic or open appendectomy and in another 17 patients allocated randomly...... to either carbon dioxide pneumoperitoneum or abdominal wall lifting for laparoscopic colectomy. Despite an increasing metabolic acidosis, prolonged carbon dioxide pneumoperitoneum resulted in only a slight increase in plasma potassium concentrations, which was both statistically and clinically insignificant....... Thus hyperkalaemia is unlikely to develop in patients with normal renal function undergoing carbon dioxide pneumoperitoneum for laparoscopic surgery....

  4. Different carbon sources affect PCB accumulation by marine bivalves.

    Science.gov (United States)

    Laitano, M V; Silva Barni, M F; Costa, P G; Cledón, M; Fillmann, G; Miglioranza, K S B; Panarello, H O

    2016-02-01

    Pampean creeks were evaluated in the present study as potential land-based sources of PCB marine contamination. Different carbon and nitrogen sources from such creeks were analysed as boosters of PCB bioaccumulation by the filter feeder bivalve Brachidontes rodriguezii and grazer limpet Siphonaria lessoni. Carbon of different source than marine and anthropogenic nitrogen assimilated by organisms were estimated through their C and N isotopic composition. PCB concentration in surface sediments and mollusc samples ranged from 2.68 to 6.46 ng g(-1) (wet weight) and from 1074 to 4583 ng g(-1) lipid, respectively, reflecting a punctual source of PCB contamination related to a landfill area. Thus, despite the low flow of creeks, they should not be underestimated as contamination vectors to the marine environment. On the other hand, mussels PCB bioaccumulation was related with the carbon source uptake which highlights the importance to consider this factor when studying PCB distribution in organisms of coastal systems.

  5. Classroom Carbon Dioxide Concentration, School Attendance, and Educational Attainment

    Science.gov (United States)

    Gaihre, Santosh; Semple, Sean; Miller, Janice; Fielding, Shona; Turner, Steve

    2014-01-01

    Background: We tested the hypothesis that classroom carbon dioxide (CO[subscript 2]) concentration is inversely related to child school attendance and educational attainment. Methods: Concentrations of CO[subscript 2] were measured over a 3-5?day period in 60 naturally ventilated classrooms of primary school children in Scotland. Concentrations of…

  6. Barrow Black Carbon Source and Impact Study Final Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Tate

    2014-07-01

    The goal of the Barrow Black Carbon Source and Impact campaign was to characterize the concentration and isotopic composition of carbonaceous atmospheric particulate matter (PM) at the Atmospheric Radiation Measurement (ARM) Climate Research Facility site in Barrow, Alaska. The carbonaceous component was characterized by measuring the organic and black carbon (OC and BC) components of the total PM. To facilitate complete characterization of the PM, filter-based collections were used, including a medium volume PM2.5 sampler and a high volume PM10 sampler. Thirty-eight fine PM fractions (PM2.5) and 49 coarse (PM10) PM fractions were collected at weekly and bi-monthly intervals. The PM2.5 sampler operated with minimal maintenance during the 12 month campaign. The PM10 sampler used for the Barrow Black Carbon Source and Impact (BBCSI) study used standard Tisch “hi-vol” motors that have a known lifetime of approximately 1 month under constant use; this necessitated monthly maintenance, and it is suggested that, for future deployment in the Arctic, the motors be upgraded to industrial blowers. The BBCSI sampling campaign successfully collected and archived 87 ambient atmospheric PM samples from Barrow, Alaska, from July 2012 to June 2013. Preliminary analysis of the OC and BC concentrations has been completed. This campaign confirmed known trends of high BC lasting from the winter through to spring haze periods and low BC concentrations in the summer. However, the annual OC concentrations had a very different seasonal pattern with the highest concentrations during the summer, lowest concentrations during the fall, and increased concentrations during the winter and spring (Figure 1).

  7. [Differences and sources of CO2 concentration, carbon and oxygen stable isotope composition between inside and outside of a green space system and influencing factors in an urban area].

    Science.gov (United States)

    Sun, Shou-jia; Meng, Ping; Zhang, Jin-song; Shu, Jian-hua; Zheng, Ning

    2015-10-01

    The off-axis integrated cavity output spectroscopy technique was used to measure air CO2 concentration, stable carbon (δ13C) and oxygen (δ18C) isotope ratios on the Fourth Ring Road (FRR) and in the green space system of Beijing Institute of Landscape Architecture (BILA) in summer and winter seasons. The variations of CO2 concentration, δ13C value, δ18C value and the differences of them between the FRR and the BILA, which were correlated with traffic volume and meteorological factors, were analyzed at half-hour timescale. The results showed that traffic volume on the FRR was large both in summer and winter with obvious morning and evening rush hours, and more than 150 thousands vehicles were observed everyday during the observation periods. Diurnal variation of the CO2 concentration showed a two-peak curve both on the FRR and in the green space system of the BILA. In contrast, diurnal variation of δ13C value was a two-trough curve while diurnal variation of δ18O value was a single-trough curve. The differences of CO2 concentration, δ13C value and δ18O value between the FRR and the green space system of BILA in summer were greater than those in winter. The carbon isotope partitioning results showed that in summer vehicle exhaust contributed 64.9% to total atmospheric CO2 of the FRR during measurement time, while heterotrophic respiration contributed 56.3% to total atmospheric CO2 of the green space system in BILA. However, in winter atmospheric CO2 from both the FRR and green space system mostly came from vehicle exhaust. Stepwise regression analysis indicated that differences of CO2 concentration between the FRR and green space system were significantly related to vehicle volume and solar radiation at half-hour timescale, while solar radiation and relative humidity were the main meteorological factors causing δ13 and δ18O differences between the FRR and green space system. Plants in the green space system strongly assimilated CO2 from fossil fuel burning

  8. [Differences and sources of CO2 concentration, carbon and oxygen stable isotope composition between inside and outside of a green space system and influencing factors in an urban area].

    Science.gov (United States)

    Sun, Shou-jia; Meng, Ping; Zhang, Jin-song; Shu, Jian-hua; Zheng, Ning

    2015-10-01

    The off-axis integrated cavity output spectroscopy technique was used to measure air CO2 concentration, stable carbon (δ13C) and oxygen (δ18C) isotope ratios on the Fourth Ring Road (FRR) and in the green space system of Beijing Institute of Landscape Architecture (BILA) in summer and winter seasons. The variations of CO2 concentration, δ13C value, δ18C value and the differences of them between the FRR and the BILA, which were correlated with traffic volume and meteorological factors, were analyzed at half-hour timescale. The results showed that traffic volume on the FRR was large both in summer and winter with obvious morning and evening rush hours, and more than 150 thousands vehicles were observed everyday during the observation periods. Diurnal variation of the CO2 concentration showed a two-peak curve both on the FRR and in the green space system of the BILA. In contrast, diurnal variation of δ13C value was a two-trough curve while diurnal variation of δ18O value was a single-trough curve. The differences of CO2 concentration, δ13C value and δ18O value between the FRR and the green space system of BILA in summer were greater than those in winter. The carbon isotope partitioning results showed that in summer vehicle exhaust contributed 64.9% to total atmospheric CO2 of the FRR during measurement time, while heterotrophic respiration contributed 56.3% to total atmospheric CO2 of the green space system in BILA. However, in winter atmospheric CO2 from both the FRR and green space system mostly came from vehicle exhaust. Stepwise regression analysis indicated that differences of CO2 concentration between the FRR and green space system were significantly related to vehicle volume and solar radiation at half-hour timescale, while solar radiation and relative humidity were the main meteorological factors causing δ13 and δ18O differences between the FRR and green space system. Plants in the green space system strongly assimilated CO2 from fossil fuel burning

  9. USE OF STABLE CARBON ISOTOPE RATIOS OF FATTY ACIDS TO EVALUATE MICROBIAL CARBON SOURCES IN TERRESTRIAL ENVIRONMENTS

    Science.gov (United States)

    We use measurements of the concentration and stable carbon isotopic ratio (D 13C) of individual microbial phospholipid fatty acids (PLFAs) in soils as indicators of live microbial biomass levels and microbial carbon source. We found that intensive sugar cane cultivation leads to ...

  10. Double-walled carbon nanotubes synthesized using carbon black as the dot carbon source

    Science.gov (United States)

    Chen, Zhi-Gang; Li, Feng; Ren, Wen-Cai; Cong, Hongtao; Liu, Chang; Qing Lu, Gao; Cheng, Hui-Ming

    2006-07-01

    Double-walled carbon nanotubes (DWNTs) were synthesized used carbon black as the dot carbon source by a semi-continuous hydrogen arc discharge process. High-resolution transmission electron microscopy (HRTEM) observations revealed that most of the tubes were DWNTs with outer and inner diameters in the range of 2.67-4 nm and 1.96-3.21 nm, respectively. Most of the DWNTs were in a bundle form of about 10-30 nm in diameter with high purity (about 70%) from thermal gravimetric analysis (TGA), resonant laser Raman spectroscopy, scanning electron microscopy (SEM) and TEM characterizations. It was found that carbon black as the dot carbon source could be easy controlled to synthesize one type of nanotube. A simple process combining oxidation and acid treatment to purify the DWNT bundles was used without damaging the bundles. The structure of carbon black, as the key element for influencing purity, bundle formation and purification of DWNTs, is discussed.

  11. Effect of carbon source on the denitrification in constructed wetlands

    Institute of Scientific and Technical Information of China (English)

    LU Songliu; HU Hongying; SUN Yingxue; YANG Jia

    2009-01-01

    The constructed wetlands with different plants in removal of nitrate were investigated.The factors promoting the rates of denitrification including organic carbon, nitrate load, plants in wetlands, pH and water temperature in field were systematically investigated.The results showed that the additional carbon source (glucose) can remarkably improve the nitrate removal ability of the constructed wetland.It demonstrated that the nitrate removal rate can increase from 20% to more than 50% in the summer and from 10% to 30% in the winter, when the nitrate concentration was 30-40 mg/L, the retention time was 24 h and 25 mg/L dissolved organic carbon (DOC) was ploughed into the constructed wetland.However, the nitrite in the constructed wetland accumulated a litter with the supply of the additional carbon source in summer and winter, and it increased from 0.15 to 2 mg/L in the effluent.It was also found that the abilities of plant in adjusting pH and temperature can result in an increase of denitrification in wetlands, and the seasonal change may impact the denitrification.

  12. Trace Metal Source Terms in Carbon Sequestration Environments

    Energy Technology Data Exchange (ETDEWEB)

    Karamalidis, Athanasios K; Torres, Sharon G; Hakala, J Alexandra; Shao, Hongbo; Cantrell, Kirk J; Carroll, Susan

    2012-02-05

    Carbon dioxide sequestration in deep saline and depleted oil geologic formations is feasible and promising, however, possible CO₂ or CO₂-saturated brine leakage to overlying aquifers may pose environmental and health impacts. The purpose of this study was to experimentally define trace metal source terms from the reaction of supercritical CO₂, storage reservoir brines, reservoir and cap rocks. Storage reservoir source terms for trace metals are needed to evaluate the impact of brines leaking into overlying drinking water aquifers. The trace metal release was measured from sandstones, shales, carbonates, evaporites, basalts and cements from the Frio, In Salah, Illinois Basin – Decatur, Lower Tuscaloosa, Weyburn-Midale, Bass Islands and Grand Ronde carbon sequestration geologic formations. Trace metal dissolution is tracked by measuring solution concentrations over time under conditions (e.g. pressures, temperatures, and initial brine compositions) specific to the sequestration projects. Existing metrics for Maximum Contaminant Levels (MCLs) for drinking water as defined by the U.S. Environmental Protection Agency (U.S. EPA) were used to categorize the relative significance of metal concentration changes in storage environments due to the presence of CO₂. Results indicate that Cr and Pb released from sandstone reservoir and shale cap rock exceed the MCLs by an order of magnitude while Cd and Cu were at or below drinking water thresholds. In carbonate reservoirs As exceeds the MCLs by an order of magnitude, while Cd, Cu, and Pb were at or below drinking water standards. Results from this study can be used as a reasonable estimate of the reservoir and caprock source term to further evaluate the impact of leakage on groundwater quality.

  13. Spatio-temporal variations of black carbon concentrations in the Megacity Beijing.

    Science.gov (United States)

    Schleicher, Nina; Norra, Stefan; Fricker, Mathieu; Kaminski, Uwe; Chen, Yizhen; Chai, Fahe; Wang, Shulan; Yu, Yang; Cen, Kuang

    2013-11-01

    The spatial and temporal distribution and the flux of black carbon (BC) concentration in Beijing were continuously investigated over a two-year period at five sites to highlight the relative influence of contributing sources. The results demonstrate firstly that there is significant spatio-temporal variability of BC in Beijing. Highest concentrations occurred during winter primarily due to stagnant meteorological conditions, and seasonal BC sources, such as coal combustion for heating purposes. Biomass burning was identified as a minor seasonal source during the summer months. BC also varied spatially with higher concentrations in the SE of Beijing and lower concentrations in the NW, due to the differing emission intensity of various local BC sources such as traffic and industry. Frequently, overnight BC concentrations were higher due to specific meteorological conditions, such as the lower urban mixing layer height and various anthropogenic activities, such as exclusive night-time heavy duty vehicle traffic in the inner-city.

  14. Treatment of hydroponic wastewater by denitrification filters using plant prunings as the organic carbon source.

    Science.gov (United States)

    Park, J B K; Craggs, R J; Sukias, J P S

    2008-05-01

    This study investigated the feasibility of using pre-treated plant liquors as organic carbon sources for the treatment of hydroponic wastewater containing high nitrate-N (>300 mg N/L). The waste plant material was pre-treated to extract organic carbon-rich liquors. When this plant liquor was used as an organic carbon source in denitrification filters at the organic carbon:nitrogen dose rate of 3C:N, nitrate removal efficiencies were >95% and final effluent nitrate concentrations were consistently 140 mg/L) of organic carbon (fBOD5) remained in the final effluents. Therefore, a 'compromise' organic carbon:nitrogen dose rate (2C:N) was trialled, at which nitrate removal efficiencies were maintained at >85%, final effluent nitrate concentrations were consistently below 45 mg N/L, and effluent fBOD5 concentrations were hydroponic wastewater in a denitrification filter. PMID:17714940

  15. Barrow Black Carbon Source and Impact Study Final Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Tate [Baylor Univ., Waco, TX (United States)

    2014-07-01

    The goal of the Barrow Black Carbon Source and Impact (BBCSI) Study was to characterize the concentration and isotopic composition of carbonaceous atmospheric particulate matter (PM) at the Atmospheric Radiation Measurement site in Barrow, AK. The carbonaceous component was characterized via measurement of the organic and black carbon (OC and BC) components of the total PM. To facilitate complete characterization of the particulate matter, filter-based collections were used, including a medium volume PM2.5 sampler and a high volume PM10 sampler. Thirty-eight fine (PM2.5) and 49 coarse (PM10) particulate matter fractions were collected at weekly and bi-monthly intervals. The PM2.5 sampler operated with minimal maintenance during the 12 month campaign. The PM10 sampler used for the BBCSI used standard Tisch hi-vol motors which have a known lifetime of ~1 month under constant use; this necessitated monthly maintenance and it is suggested that the motors be upgraded to industrial blowers for future deployment in the Arctic. The BBCSI sampling campaign successfully collected and archived 87 ambient atmospheric particulate matter samples from Barrow, AK from July 2012 to June 2013. Preliminary analysis of the organic and black carbon concentrations has been completed. This campaign confirmed known trends of high BC lasting from the winter through to spring haze periods and low BC concentrations in the summer.

  16. Direct measurement of surface carbon concentrations. [in lunar soil

    Science.gov (United States)

    Filleux, C.; Tombrello, T. A.; Burnett, D. S.

    1977-01-01

    Measurements of surface concentrations of carbon in lunar soils and soil breccias provide information on the origin of carbon in the regolith. The reaction C-12 (d, p sub zero) is used to measure 'surface' and 'volume' concentrations in lunar samples. This method has a depth resolution of 1 micron, which permits only a 'surface' and a 'volume' component to be measured. Three of four Apollo 16 double drive tube samples show a surface carbon concentration of about 8 by 10 to the 14th power/sq cm, whereas the fourth sample gave 4 by 10 to the 14th power/sq cm. It can be convincingly shown that the measured concentration does not originate from fluorocarbon or hydrocarbon contaminants. Surface adsorbed layers of CO or CO2 are removed by a sputter cleaning procedure using a 2-MeV F beam. It is shown that the residual C concentration of 8 by 10 to the 14th power/sq cm cannot be further reduced by increased F fluence, and it is therefore concluded that it is truly lunar. If one assumes that the measured surface C concentration is a steady-state concentration determined only by a balance between solar-wind implantation and sputtering, a sputter erosion rate of 0.1 A/yr is obtained. However, it would be more profitable to use an independently derived sputter erosion rate to test the hypothesis of a solar-wind origin of the surface carbon.

  17. Enhanced biological phosphorus removal with different carbon sources.

    Science.gov (United States)

    Shen, Nan; Zhou, Yan

    2016-06-01

    Enhanced biological phosphorus removal (EBPR) process is one of the most economical and sustainable methods for phosphorus removal from wastewater. However, the performance of EBPR can be affected by available carbon sources types in the wastewater that may induce different functional microbial communities in the process. Glycogen accumulating organisms (GAOs) and polyphosphate accumulating organisms (PAOs) are commonly found by coexisting in the EBPR process. Predominance of GAO population may lead to EBPR failure due to the competition on carbon source with PAO without contributing phosphorus removal. Carbon sources indeed play an important role in alteration of PAOs and GAOs in EBPR processes. Various types of carbon sources have been investigated for EBPR performance. Certain carbon sources tend to enrich specific groups of GAOs and/or PAOs. This review summarizes the types of carbon sources applied in EBPR systems and highlights the roles of these carbon sources in PAO and GAO competition. Both single (e.g., acetate, propionate, glucose, ethanol, and amino acid) and complex carbon sources (e.g., yeast extract, peptone, and mixed carbon sources) are discussed in this review. Meanwhile, the environmental friendly and economical carbon sources that are derived from waste materials, such as crude glycerol and wasted sludge, are also discussed and compared. PMID:27087523

  18. Influence of the carbon dioxide concentration on the resistance to carbonation of concrete

    NARCIS (Netherlands)

    Visser, J.H.M.

    2013-01-01

    Carbonation of concrete at ambient CO2 concentration is a slow process. This makes the testing of the resistance of concrete against carbonation often too slow to be applicable for service life assessments of new structures. Raising the CO2-concentration will accelerate the test but the validity of

  19. Improved Dispersion of Carbon Nanotubes in Polymers at High Concentrations

    OpenAIRE

    Chao-Xuan Liu; Jin-Woo Choi

    2012-01-01

    The polymer nanocomposite used in this work comprises elastomer poly(dimethylsiloxane) (PDMS) as a polymer matrix and multi-walled carbon nanotubes (MWCNTs) as a conductive nanofiller. To achieve uniform distribution of carbon nanotubes within the polymer, an optimized dispersion process was developed, featuring a strong organic solvent—chloroform, which dissolved PDMS base polymer easily and allowed high quality dispersion of MWCNTs. At concentrations as high as 9 wt.%, MWCNTs were...

  20. Black carbon as a carbon source for young soils in a glacier forefield?

    Science.gov (United States)

    Eckmeier, E.; Pichler, B.; Krebs, R.; Mavris, C.; Egli, M.

    2012-04-01

    Most evident changes in Alpine soils today occur in proglacial areas where existing young soils are continuously developing. Due to climate change, additional areas will become ice-free and subject to weathering and new soil formation. The glacier forefields of the European Alps are continuously exposed since the glaciers reached their maximum expansion in the 1850s. In these proglacial areas, initial soils have started to develop so that they may offer, under optimal conditions, a continuous chronosequence from 0 to 150 year-old soils. The buildup of organic carbon (Corg) in soil is an important factor controlling weathering and the formation of soils. Not only autochthonous but also distant (allochthonous) sources may contribute to the accumulation of soil organic carbon in young soils and surfaces of glacier forefields. Black carbon could be an important component in Alpine soils. However, only little is known about black carbon in very young soils that develop in glacier forefields. The aim of our study was to examine whether black carbon as an allochthonous source of soil organic matter can be detected in the initial soils, and to estimate its relative contribution (as a function of time) to total organic carbon. We investigated surface soil samples (topsoils, A or AO horizon) from 35 sites distributed over the whole proglacial area of Morteratsch, where ideal conditions for a soil chronosequence from 0 to 150 years can be found. Along this sequence, bare till sediments to weakly developed soils (Leptosols) can be encountered. Black carbon concentrations were determined in fine-earth using the benzene polycarboxylic acid (BPCA) marker method as described by Brodowski et al. (2005). We found that the proportion of BPCA-C to total Corg was related to the time since the surface was exposed. The youngest soils (younger than 40 years) contained the highest proportion of BPCA-C (up to 120 g BPCA-C/kg Corg). In these soils, however, the Corg concentrations were very

  1. Black Carbon Concentration from Worldwide Aerosol Robotic Network (AERONET)

    Science.gov (United States)

    Schuster, Greg; Dubovik, Oleg; Holben, Brent; Clothiaux, Eugene

    2008-01-01

    Worldwide black carbon concentration measurements are needed to assess the efficacy of the carbon emissions inventory and transport model output. This requires long-term measurements in many regions, as model success in one region or season does not apply to all regions and seasons. AERONET is an automated network of more than 180 surface radiometers located throughout the world. The sky radiance measurements obtained by AERONET are inverted to provide column-averaged aerosol refractive indices and size distributions for the AERONET database, which we use to derive column-averaged black carbon concentrations and specific absorptions that are constrained by the measured radiation field. This provides a link between AERONET sky radiance measurements and the elemental carbon concentration of transport models without the need for an optics module in the transport model. Knowledge of both the black carbon concentration and aerosol absorption optical depth (i.e., input and output of the optics module) will enable improvements to the transport model optics module.

  2. Size distributions, sources and source areas of water-soluble organic carbon in urban background air

    Directory of Open Access Journals (Sweden)

    H. Timonen

    2008-09-01

    Full Text Available This paper represents the results of one year long measurement period of the size distributions of water-soluble organic carbon (WSOC, inorganic ions and gravimetric mass of particulate matter. Measurements were done at an urban background station (SMEAR III by using a micro-orifice uniform deposit impactor (MOUDI. The site is located in northern European boreal region in Helsinki, Finland. The WSOC size distribution measurements were completed with the chemical analysis of inorganic ions, organic carbon (OC and monosaccharide anhydrides from the filter samples (particle aerodynamic diameter smaller than 1 μm, PM1. Gravimetric mass concentration varied during the MOUDI samplings between 3.4 and 55.0 μg m−3 and the WSOC concentrations were between 0.3 and 7.4 μg m−3. On average, water-soluble particulate organic matter (WSPOM, WSOC multiplied by 1.6 to convert the analyzed carbon mass to organic matter mass comprised 25±7.7% and 7.5±3.4% of aerosol PM1 mass and the PM1–10 mass, respectively. Inorganic ions contributed 33±12% and 28±19% of the analyzed PM1 and PM1–10 aerosol mass.

    Five different aerosol categories corresponding to different sources or source areas were identified (long-range transport aerosols, biomass burning aerosols from wild land fires and from small-scale wood combustion, aerosols originating from marine areas and from the clean arctic areas. Categories were identified mainly using levoglucosan concentration level for wood combustion and air mass backward trajectories for other groups. Clear differences in WSOC concentrations and size distributions originating from different sources or source areas were observed, although there are also many other factors which might affect the results. E.g. the local conditions and sources of volatile organic compounds (VOCs and aerosols as well as various transformation processes are likely

  3. Present possibilities of protein concentrates production from plant sources

    OpenAIRE

    KRISTINOVÁ, Helena

    2011-01-01

    The aim of the bachelor thesis was gather information about present possibilities of proteins concentrates production from plant sources. I focused on dried pea (Pisum sativum L.), soybean (Glycine soja) and potato tuber (Solanum tuberosum L.). The protein concentrates from leguminous plants are produced by three basic processes, i.e. acid leasing (at ~pH 4.5), extracting with aqueous alcohol (60 - 90%), and denaturing the protein with moist heat before extraction with water. Pea protein is p...

  4. Carbon sources and fates in the Gulf of Papua

    Science.gov (United States)

    Goni, M. A.; Monacci, N. M.; Gisewhite, R. A.; Ogston, A.; Crockett, J.; Nittrouer, C.

    2006-12-01

    Seabed sediments were collected along the particle-dispersal system associated with the Fly River-Gulf of Papua continental margin as part of the source to sink program in Papua New Guinea. Box and kasten cores were collected from the subaqueous delta located adjacent to the mouth of the Fly River as well as from the topset, foreset and bottomset regions of the active clinoform in the northern region of the Gulf of Papua. Analyses of elemental (organic carbon, inorganic carbon, nitrogen), stable isotopic (d13C and d15N), radiocarbon (14C), and biomarker (CuO oxidation products) signatures reveal significant differences in the content and composition of sedimentary organic matter (OM) along the dispersal system. The major sources of OM to the system appear to be remains of vascular plants, soil OM from the drainage basin, and materials derived from autochthonous productivity. The geographical contrasts in the concentrations and accumulation fluxes of these distinct types of allochthonous and autochthonous OM are presented in the context of patterns of sediment transport and deposition within the region. An overall OM budget for the whole dispersal system will be presented and its implication for carbon sequestration in fluvial-dominated continental margins discussed.

  5. Young organic matter as a source of carbon dioxide outgassing from Amazonian rivers

    Energy Technology Data Exchange (ETDEWEB)

    Mayorga, E; Aufdenkampe, A K; Masiello, C A; Krusche, A V; Hedges, J I; Quay, P D; Richey, J E; Brown, T A

    2005-06-23

    Rivers are generally supersaturated with respect to carbon dioxide, resulting in large gas evasion fluxes that can be a significant component of regional net carbon budgets. Amazonian rivers were recently shown to outgas more than ten times the amount of carbon exported to the ocean in the form of total organic carbon or dissolved inorganic carbon. High carbon dioxide concentrations in rivers originate largely from in situ respiration of organic carbon, but little agreement exists about the sources or turnover times of this carbon. Here we present results of an extensive survey of the carbon isotope composition ({sup 13}C and {sup 14}C) of dissolved inorganic carbon and three size-fractions of organic carbon across the Amazonian river system. We find that respiration of contemporary organic matter (less than 5 years old) originating on land and near rivers is the dominant source of excess carbon dioxide that drives outgassing in mid-size to large rivers, although we find that bulk organic carbon fractions transported by these rivers range from tens to thousands of years in age. We therefore suggest that a small, rapidly cycling pool of organic carbon is responsible for the large carbon fluxes from land to water to atmosphere in the humid tropics.

  6. Study on Behavior of Carbon Reduction of Monazite Concentrate

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The behavior of monazite concentrate reduced by carbon, especially the decomposed procedure of rare earth phosphates, was investigated by X-ray diffraction , electron probe, TG method and chemical analysis. The results show that rare earth phosphates in monazite concentrate can be reduced to their oxides, among them the decomposition processes of cerium phosphate are not in step with lanthanum phosphate, neodymium phosphate and so on, and the phosphorus was volatilized into air in simple form.

  7. Source Molecular Effect on Amorphous Carbon Film Deposition

    OpenAIRE

    Kawazoe, Hiroki; Inayoshi, Takanori; Shinohara, Masanori; Matsuda, Yoshinobu; Fujiyama, Hiroshi; Nitta, Yuki; Nakatani, Tatsuyuki

    2009-01-01

    We investigated deposition process of amorphous carbon films using acetylene and methane as a source molecule, by using infrared spectroscopy in multiple internal reflection geometry (MIR-IRAS). We found that deposited film structures were different due to source molecules.

  8. Measurements of atmospheric carbon dioxide concentration above the ocean

    Energy Technology Data Exchange (ETDEWEB)

    Voskresenskii, A.I.; Kamenogradskii, N.E.

    1984-01-01

    Changes in the composition of the atmosphere can have a destabilizing effect on the climate. One change is related to an increase in the concentration of carbon dioxide as a result of the combustion of organic fuels. The most effective procedures for monitoring the atmospheric carbon dioxide concentration are discussed, taking into account suitable analytic methods and the most appropriate locations for the conduction of the measurements. It is found that polar and oceanic regions are best suited for the performance of the considered measurements. The analytic procedure selected is based on a spectroscopic approach utilizing the absorption of solar radiation by carbon dioxide at a wavelength of 2.06 microns. A description is given of measurements conducted on Soviet expeditions to the Antarctic during the time from 1979 to 1981. The concentration of atmospheric carbon dioxide as a function of geographic latitude is shown in graphs, taking into account data for January, February, March, and April. Water vapor concentrations are also shown. 11 references.

  9. Carbon dioxide concentration in Mediterranean greenhouses : how much lost production?

    NARCIS (Netherlands)

    Stanghellini, C.; Incrocci, L.; Gazquez, J.C.; Dimauro, B.

    2008-01-01

    In the absence of artificial supply of carbon dioxide in the greenhouse environment, the CO2 absorbed in the process of photosynthesis must ultimately come from the external ambient through the ventilation openings. This requires that the CO2 concentration within the house must be lower than the ext

  10. Effects of Temperature and Catalyst Concentration on the Growth of Aligned Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    BAI Xiaodong; LI Dan; WANG Ye; LIANG Ji

    2005-01-01

    The effects of preheating and pyrolysis temperatures and catalyst concentration on the synthesis of aligned carbon nanotubes (CNTs) using ferrocene as the catalyst and xylene as the carbon source in chemical vapor deposition were experimentally studied. The as-grown aligned CNTs were characterized by field emission scanning electron microscopy, transmission electronic microscopy, high-resolution transmission electronic microscopy, and Raman spectroscopy. The growth rate, the diameters, and the degree of crystal structure of the aligned CNTs were all found to depend on the preheating and pyrolysis temperatures and the catalyst concentration. The optimized conditions for the growth of aligned CNTs resulted in a rapid growth rate of 20.4 μm/min, with the CNTs having a good, uniform crystal structure, and clean surfaces with little amorphous carbon. The results also show that higher preheating temperatures and lower ferrocene concentrations favor the growth of single-walled CNTs.

  11. Secondary organic carbon quantification and source apportionment of PM10 in Kaifeng, China

    Institute of Scientific and Technical Information of China (English)

    WU Lin; FENG Yinchang; WU Jianhui; ZHU Tan; BI Xiaohui; HAN Bo; YANG Weihong; YANG Zhiqiang

    2009-01-01

    During 2005, the filter samples of ambient PM10 from five sites and the source samples of particulate matter were collected in Kaifeng, Henan province of China. Nineteen elements, water-soluble ions, total carbon (TC) and organic carbon (OC) contained in samples were analyzed. Seven contributive source types were identified and their contributions to ambient PM10 were estimated by chemical mass balance (CMB) receptor model. Weak associations between the concentrations of organic carbon and element carbon (EC) were observed during the sampling periods, indicating that there was secondary organic aerosol pollution in the urban atmosphere. An indirect method of "OC/EC minimum ratio" was applied to estimate the concentration of secondary organic carbon (SOC). The results showed that SOC contributed 26.2%, 32.4% and 18.0% of TC in spring, summer-fall and winter respectively, and the annual average SOC concentration was 7.07 μg/m3, accounting for 5.73% of the total mass in ambient PM10. The carbon species concentrations in ambient PM10 were recalculated by subtracting the SOC concentrations from measured concentrations of TC and OC to increase the compatibility of source and receptor measurements for CMB model.

  12. Influence of oxygen concentration, fuel composition, and strain rate on synthesis of carbon nanomaterials

    International Nuclear Information System (INIS)

    This paper investigates the influence of flame parameters including oxygen concentration, fuel composition, and strain rate on the synthesis of carbon nanomaterials in opposed-jet ethylene diffusion flames with or without rigid-body rotation. In the experiments, a mixture of ethylene and nitrogen was introduced from the upper burner; meanwhile, a mixture of oxygen and nitrogen was supplied from the lower burner. A nascent nickel mesh was used as the catalytic metal substrate to collect deposited materials. With non-rotating opposed-jet diffusion flames, carbon nanotubes (CNTs) were successfully produced for oxygen concentrations in the range of 21–50 % at a fixed ethylene concentration of 20 %, and for ethylene concentrations ranging from 14 to 24 % at a constant oxygen concentration of 40 %. With rotating opposed-jet diffusion flames, the strain rate was varied by adjusting the angular velocities of the upper and lower burners. The strain rate governed by flow rotation greatly affects the synthesis of carbon nanomaterials [i.e., CNTs and carbon nano-onions (CNOs)] either through the residence time or carbon sources available. An increase in the angular velocity lengthened the residence time of the flow and thus caused the diffusion flame to experience a decreased strain rate, which in turn produced more carbon sources. The growth of multi-walled CNTs was achieved for the stretched flames experiencing a higher strain rate [i.e., angular velocity was equal to 0 or 1 rotations per second (rps)]. CNOs were synthesized at a lower strain rate (i.e., angular velocity was in the range of 2–5 rps). It is noteworthy that the strain rate controlled by flow rotation greatly influences the fabrication of carbon nanostructures owing to the residence time as well as carbon source. Additionally, more carbon sources and higher temperature are required for the synthesis of CNOs compared with those required for CNTs (i.e., about 605–625 °C for CNTs and 700–800 °C for

  13. High-brightness source based on luminescent concentration.

    Science.gov (United States)

    de Boer, Dick K G; Bruls, Dominique; Jagt, Henri

    2016-07-11

    The concept of a high-luminance light source based on luminescent conversion of LED light and optical concentration in a transparent phosphor is explained. Experiments on a realized light source show that a luminous flux of 8500 lm and a luminance of 500 cd/mm2 can be attained using 56 pump LEDs at 330 W electrical input power. The measurement results are compared to optical simulations, showing that the experimental optical efficiency is slightly lower than expected. The present status enables applications like mid-segment digital projection using LED technology, whereas the concept is scalable to higher fluxes. PMID:27410894

  14. Source of variation of isoflavone concentrations in perennial clover species

    OpenAIRE

    Bronislava Butkute; Butkute Lemeziene; Giedre Dabkeviciene; Valdas Jakstas; Egidijus Vilcinskas; Valdimaras Janulis

    2014-01-01

    Introduction: Clover has attracted considerable interest not only as a valuable livestock forage plant, but also as an important source of isoflavones. The current study was aimed to assess the variation of concentration of three isoflavones in clover species grown under a cool temperate climate environment in Lithuania. Materials and Methods: Isoflavone contents were quantified in the plant parts of 21 accessions belonging to five perennial species of genus Trifolium (T. pratense, T. repens,...

  15. Modeling contaminant concentration distributions in China's centralized source waters.

    Science.gov (United States)

    Wu, Rui; Qian, Song S; Hao, Fanghua; Cheng, Hongguang; Zhu, Dangsheng; Zhang, Jianyong

    2011-07-15

    Characterizing contaminant occurrences in China's centralized source waters can provide an understanding of source water quality for stakeholders. The single-factor (i.e., worst contaminant) water-quality assessment method, commonly used in Chinese official analysis and publications, provides a qualitative summary of the country's water-quality status but does not specify the extent and degree of specific contaminant occurrences at the national level. Such information is needed for developing scientifically sound management strategies. This article presents a Bayesian hierarchical modeling approach for estimating contaminant concentration distributions in China's centralized source waters using arsenic and fluoride as examples. The data used are from the most recent national census of centralized source waters in 2006. The article uses three commonly used source water stratification methods to establish alternative hierarchical structures reflecting alternative model assumptions as well as competing management needs in characterizing pollutant occurrences. The results indicate that the probability of arsenic exceeding the standard of 0.05 mg/L is about 0.96-1.68% and the probability of fluoride exceeding 1 mg/L is about 9.56-9.96% nationally, both with strong spatial patterns. The article also discusses the use of the Bayesian approach for establishing a source water-quality information management system as well as other applications of our methods. PMID:21692445

  16. Comparison of aerobic denitrifying activity among three cultural species with various carbon sources.

    Science.gov (United States)

    Otani, Y; Hasegawa, K; Hanaki, K

    2004-01-01

    Abilities of three aerobic denitrifiers such as Alcaligenes faecalis, Microvirgula aerodenitrificans and Paracoccus pantotrophus were compared from the viewpoints of nitrate removal efficiency and organic matter utilization. First, the effect of carbon source was investigated. Although nitrate reduction was observed in all strains under aerobic conditions, a change of carbon source considerably affected the denitrification ability. In the case of P. pantotrophus, nitrate and nitrite were completely removed in three days under sodium acetate or leucine as a carbon source. In the case of A. faecalis, sufficient nitrate removal was observed only when sodium acetate or ethanol was added. P. pantotrophus and A. faecalis showed a higher ability of nitrate removal than that of M. aerodenitrificans. Therefore, P. pantotrophus was selected in order to investigate the effects of concentration and repetitive addition of carbon. Sodium acetate was used as a sole carbon source. Nitrate was not reduced when the carbon concentration was below 500 mgC/L. However, when carbon source was added repeatedly, nitrate was reduced under 100 mgC/L after the optical density of the bacterium reached above 1.0. This result indicated that a high enough level of bacterial density was necessary to express aerobic denitrification activity. PMID:15566182

  17. The geographic concentration of blue carbon in the continental US

    Science.gov (United States)

    Feagin, R. A.; Hinson, A.

    2014-12-01

    Salt water wetlands have the potential to be bought and sold as relatively rich reservoirs of carbon in the context of sequestration projects. However, little is known about the geographic distribution of this potential, and no coarse scale investigation has addressed this ecosystem service at the continental scale. Our objective was to determine blue carbon stocks and flux in coastal wetland soils in the United States and categorize the potential for projects by estuarine basin, state, and wetland type. We linked National Wetlands Inventory (NWI) data with the Soil Survey Geographic Database (SSURGO) through spatial analysis within a Geographic Information System (GIS). We then calculated and mapped soil organic carbon across the continental US. Results were filtered by state, estuarine basin, wetland type, and accumulation rate, and ranking lists for each categorization were produced. The results showed that belowground carbon accumulation is concentrated in specific regions, with the richest and largest reservoirs in the Gulf and Atlantic southeastern estuaries, for example mangrove zones in Florida. Salt marshes on the southern Pacific Coast were relatively low in carbon due to small areas of coverage and the presence of sandy and inorganic soil. The geomorphic position of a wetland within a given estuary, for example on an exposed barrier island versus recessed towards inflowing headwaters, accounted for a greater degree of soil carbon variation than the wetland type, for example woody mangroves versus herbaceous marshes. The potential of a blue carbon sequestration project in relation to its location could be influential in determining wetland policy, conservation, and restoration in the coming decades.

  18. Do Vermont's Floodplains Constitute an Important Source of Labile Carbon?

    Science.gov (United States)

    Perdrial, J. N.; Dolan, A.; Kemsley, M.

    2014-12-01

    Floodplains are extremely heterogeneous landscapes with respect to soil and sediment composition and can present an important source of carbon (C) during floods. For example, stream bank soils and sediments are zones of active erosion and deposition of sediment associated C. Due to the presence of plants, riparian soils contain high amounts of C that is exchanged between stream waters and banks. Abandoned channels and meander wetlands that remain hydrologically connected to the main channel contain high amounts of organic matter that can be flushed into the stream during high discharge. This heterogeneity, result of floodplain geomorphology, land cover and use, can profoundly impact the amount and type of dissolved organic matter (DOM) introduced into streams. In order to assess DOM characteristics leached from heterogeneous floodplain soils, aqueous soil extracts were performed on soil samples representative of different land covers (n=20) at four depths. Extracts were analyzed for dissolved organic C and total dissolved nitrogen with a Shimadzu C analyzer. Colored dissolved organic matter characteristics was measured with the Aqualog Fluorescence Spectrometer and quantified with parallel factor analysis (PARAFAC). Preliminary data from three floodplains in Vermont (Connecticut, Missisquoi and Mad River) show a 3D variability of longitudinal, lateral, and vertical extents on water-extractable, mobile C. Dissolved organic carbon concentrations in meander swamp samples were found up to 9 times higher than in those of soils from agricultural field indicative of an important C source. Although C concentrations in adjacent fields were low, high abundance of labile C (indicated by tryptophan-like fluorescence) in water extracts from fields indicates recent biological production of C. This labile C is easily processed by microbes and transformed to the greenhouse gas CO2. These results provide important information on the contribution and lability of different floodplain

  19. Growth of graphene films from non-gaseous carbon sources

    Science.gov (United States)

    Tour, James; Sun, Zhengzong; Yan, Zheng; Ruan, Gedeng; Peng, Zhiwei

    2015-08-04

    In various embodiments, the present disclosure provides methods of forming graphene films by: (1) depositing a non-gaseous carbon source onto a catalyst surface; (2) exposing the non-gaseous carbon source to at least one gas with a flow rate; and (3) initiating the conversion of the non-gaseous carbon source to the graphene film, where the thickness of the graphene film is controllable by the gas flow rate. Additional embodiments of the present disclosure pertain to graphene films made in accordance with the methods of the present disclosure.

  20. Size distributions, sources and source areas of water-soluble organic carbon in urban background air

    Directory of Open Access Journals (Sweden)

    H. Timonen

    2008-04-01

    Full Text Available This paper represents the results of one year long measurement period of the size distributions of water-soluble organic carbon (WSOC, inorganic ions and gravimetric mass of particulate matter. Measurements were done at an urban background station (SMEAR III by using a micro-orifice uniform deposit impactor (MOUDI. The site is located in northern European boreal region in Helsinki, Finland. The WSOC size distribution measurements were completed with the chemical analysis of inorganic ions, organic carbon (OC and monosaccharide anhydrides from the filter samples. During the measurements gravimetric mass in the MOUDI collections varied between 3.4 and 55.0 μg m−3 and the WSOC concentration was between 0.3 and 7.4 μg m−3. On average, water-soluble particulate organic matter (WSPOM, WSOC multiplied by 1.6 comprised 25±7.7% and 7.5±3.4% of aerosol PM1 mass and the PM1−10 mass, respectively. Inorganic ions contributed 33±12% and 28±19% of the analyzed PM1 and PM1−10 aerosol mass.

    Five different aerosol categories corresponding to different sources or source areas were identified (long-range transport aerosols, biomass burning aerosols from wild land fires and from small-scale wood combustion, aerosols originating from marine areas and from the clean arctic areas. Clear differences in WSOC concentrations and size distributions originating from different sources or source areas were observed, although there are also many other factors which might affect the results. E.g. the local conditions and sources of volatile organic compounds (VOCs and aerosols as well as various transformation processes are likely to have an impact on the measured aerosol composition. Using the source categories, it was identified that especially the oxidation products of biogenic VOCs in summer had a clear effect on WSOC concentrations.

  1. Contributions of natural sources to ozone and PM concentrations

    Science.gov (United States)

    Zare, Azimeh; Christensen, Jesper; Gross, Allan; Irannejad, parviz; Glasius, Marianne; Brandt, Jørgen

    2014-05-01

    Natural emissions play an important role in determining ambient levels of harmful atmospheric pollutants, especially tropospheric ozone and particulate matter (PM). Natural sources have become more important with the ongoing reductions of anthropogenic emissions and are expected to be even more significant in the future in connection with a changing climate. Despite of the efforts made for modelling of natural emissions, the uncertainties and gaps with regard to investigation and quantification of these emissions are still quite large. In this study, the large-scale atmospheric chemistry transport model, DEHM (the Danish Eulerian Hemispheric Model) is further developed, evaluated and applied to study and quantify the contributions of many compounds from the natural sources to the concentration of ozone and formation of PM. The relative contributions are calculated for the domain covering more than the Northern Hemisphere for a typical year 2006. Natural source categories adopted in the recent model consist of vegetation, lightning, soils, wild animals and oceans. Here, DEHM has been further developed to include more natural emissions of biogenic volatile organic compounds (VOCs) as well as a scheme for describing secondary organic aerosols. Moreover, the parameterization used for estimating sea-salt generation has been modified to contain additional features. Evaluation of the modeled total fine PM, against observations, is conducted for both the previous and new model versions to assess improvement of the model performance with the updated description of natural emissions. Using the developed DEHM, our simulations indicate that at the Northern Hemisphere the contribution from natural emissions to the average annual ozone concentrations over land is between 4-30 ppbV. Among the natural emissions, biogenic VOCs are found to be the most significant contributors to ozone formation. Our results show that biogenic VOCs enhance the average ozone concentration with around

  2. Shunting arc plasma source for pure carbon ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y. [Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

    2012-02-15

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm{sup 2} at the peak of the pulse.

  3. Shunting arc plasma source for pure carbon ion beama)

    Science.gov (United States)

    Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y.

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm2 at the peak of the pulse.

  4. Shunting arc plasma source for pure carbon ion beam.

    Science.gov (United States)

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA∕mm(2) at the peak of the pulse.

  5. Shunting arc plasma source for pure carbon ion beam.

    Science.gov (United States)

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA∕mm(2) at the peak of the pulse. PMID:22380206

  6. The relationship between black carbon concentration and black smoke: A more general approach

    OpenAIRE

    Heal, Mathew R.; Quincey, Paul

    2012-01-01

    The black carbon (BC) component of ambient particulate matter is an important marker for combustion sources and for its impact on human health and radiative forcing. Extensive data archives exist for the black smoke metric, the historic measure of ambient particle darkness. An expression presented in earlier publications (Quincey, 2007; Quincey et al., 2011) for estimating BC concentrations from traditional black smoke measurements is shown to have limitations that can be addressed by using a...

  7. A Novel Airborne Carbon Isotope Analyzer for Methane and Carbon Dioxide Source Fingerprinting

    Science.gov (United States)

    Berman, E. S.; Huang, Y. W.; Owano, T. G.; Leifer, I.

    2014-12-01

    Recent field studies on major sources of the important greenhouse gas methane (CH4) indicate significant underestimation of methane release from fossil fuel industrial (FFI) and animal husbandry sources, among others. In addition, uncertainties still exist with respect to carbon dioxide (CO2) measurements, especially source fingerprinting. CO2 isotopic analysis provides a valuable in situ measurement approach to fingerprint CH4 and CO2as associated with combustion sources, leakage from geologic reservoirs, or biogenic sources. As a result, these measurements can characterize strong combustion source plumes, such as power plant emissions, and discriminate these emissions from other sources. As part of the COMEX (CO2 and MEthane eXperiment) campaign, a novel CO2 isotopic analyzer was installed and collected data aboard the CIRPAS Twin Otter aircraft. Developing methods to derive CH4 and CO2 budgets from remote sensing data is the goal of the summer 2014 COMEX campaign, which combines hyperspectral imaging (HSI) and non-imaging spectroscopy (NIS) with in situ airborne and surface data. COMEX leverages the synergy between high spatial resolution HSI and moderate spatial resolution NIS. The carbon dioxide isotope analyzer developed by Los Gatos Research (LGR) uses LGR's patented Off-Axis ICOS (Integrated Cavity Output Spectroscopy) technology and incorporates proprietary internal thermal control for high sensitivity and optimal instrument stability. This analyzer measures CO2 concentration as well as δ13C, δ18O, and δ17O from CO2 at natural abundance (100-3000 ppm). The laboratory accuracy is ±1.2 ppm (1σ) in CO2 from 370-1000 ppm, with a long-term (1000 s) precision of ±0.012 ppm. The long-term precision for both δ13C and δ18O is 0.04 ‰, and for δ17O is 0.06 ‰. The analyzer was field-tested as part of the COWGAS campaign, a pre-cursor campaign to COMEX in March 2014, where it successfully discriminated plumes related to combustion processes associated with

  8. Source identification of high glyme concentrations in the Oder River.

    Science.gov (United States)

    Stepien, D K; Püttmann, W

    2014-05-01

    The objective of the following study was to identify the source of high concentrations of glycol diethers (diglyme, triglyme, and tetraglyme) in the Oder River. Altogether four sampling campaigns were conducted and over 50 surface samples collected. During the first two samplings of the Oder River in the Oderbruch region (km 626-690), glymes were detected at concentrations reaching 0.065 μg L(-1) (diglyme), 0.54 μg L(-1) (triglyme) and 1.7 μg L(-1) (tetraglyme). The subsequent sampling of the Oder River, from the area close to the source to the Poland-Germany border (about 500 km) helped to identify the possible area of the dominating glyme entry into the river between km 310 and km 331. During that sampling, the maximum concentration of triglyme was 0.46 μg L(-1) and tetraglyme 2.2 μg L(-1); diglyme was not detected. The final sampling focused on the previously identified area of glyme entry, as well as on tributaries of the Oder River. Samples from Czarna Woda stream and Kaczawa River contained even higher concentrations of diglyme, triglyme, and tetraglyme, reaching 5.2 μg L(-1), 13 μg L(-1) and 81 μg L(-1), respectively. Finally, three water samples were analyzed from a wastewater treatment plant receiving influents from a Copper Smelter and Refinery; diglyme, triglyme, and tetraglyme were present at a maximum concentration of 1700 μg L(-1), 13,000 μg L(-1), and 190,000 μg L(-1), respectively. Further research helped to identify the source of glymes in the wastewater. The gas desulfurization process Solinox uses a mixture of glymes (Genosorb(®)1900) as a physical absorption medium to remove sulfur dioxide from off-gases from the power plant. The wastewater generated from the process and from the maintenance of the equipment is initially directed to the wastewater treatment plant where it undergoes mechanical and chemical treatment processes before being discharged to the tributaries of the Oder River. Although monoglyme was

  9. Crop soil air carbon dioxide concentration and sludge

    Energy Technology Data Exchange (ETDEWEB)

    Guiresse, M.; Gers, C.; Dourel, L.; Kaemmerer, M.; Revel, J.C. [Institut National Polytechnique de Toulouse, Toulouse (France). Ecole Nationale Superieure Agronomique de Toulouse

    1995-12-31

    The introduction of organic compounds into the soil may increase carbon dioxide emission and thus change the composition of the soil air and microfauna. These factors were studied in a field experiment in luvi-redoxisoils in the South West of France. The untreated liquid sludge from the wastewater treatment plant of Toulouse was tested. The first field plot was an unploughed plot, without any fertilizer and any sludge; the second was a control plot sown with Zea mays and a standard mineral fertilizer without any sludge; the third plot was sown with Zea mays and a normal amount of sludge; and the last plot was sown with Zea mays and a large amount of sludge. In these plots soil air dioxide carbon concentration during all the maize cultivation was measured using the Draeger field method twice a week. The results showed that burying degradable organic compounds increases soil air CO{sub 2}. 8 refs., 6 figs.

  10. Trends in the sources and sinks of carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Le Quere, Corrine [University of East Anglia, Norwich, United Kingdom; Raupach, Mike [GCP, Canberra, Australia; Canadell, J.G. [CSIRO Marine and Atmospheric Research; Marland, Gregg [ORNL; Bopp, Laurent [National Center for Scientific Research, Gif-sur-Yvette, France; Ciais, Philippe [Laboratoire des Sciences du Climat et de l' Environement, France; Friedlingstein, Pierre [National Center for Scientific Research, Gif-sur-Yvette, France; Viovy, Nicolas [National Center for Scientific Research, Gif-sur-Yvette, France; Conway, T.J. [NOAA, Boulder, CO; Doney, Scott C. [Woods Hole Oceanographic Institution; Feely, R. A. [NOAA Pacific Marine Environmental Laboratory; Foster, Pru [University of Bristol, UK; House, Joanna I [University of Bristol, UK; Prentice, Colin I. [University of Bristol, UK; Gurney, Kevin [Purdue University; Houghton, R.A. [Woods Hole Research Center, Woods Hole, MA; Huntingford, Chris [Center for Ecology and Hydrology, Oxon, England; Levy, Peter E. [Center for Ecology and Hydrology, Midlothian, Scotland; Lomas, M. R. [University of Sheffield; Woodward, F. I. [University of Sheffield; Majkut, Joseph [Princeton University; Sarmiento, Jorge L. [Princeton University; Metzl, Nicolas [University of Paris; Ometto, Jean P [ORNL; Randerson, James T. [University of California, Irvine; Peters, Glen P [Center for International Climate and Energy Research (CICERO), Oslo, Norway; Running, Steven [University of Montana, Missoula; Sitch, Stephen [University of Leeds, UK; Takahashi, Taro [Columbia University; Van der Werf, Guido [Universitate Amsterdam

    2009-12-01

    Efforts to control climate change require the stabilization of atmospheric CO2 concentrations. This can only be achieved through a drastic reduction of global CO2 emissions. Yet fossil fuel emissions increased by 29% between 2000 and 2008, in conjunction with increased contributions from emerging economies, from the production and international trade of goods and services, and from the use of coal as a fuel source. In contrast, emissions from land-use changes were nearly constant. Between 1959 and 2008, 43% of each year's CO2 emissions remained in the atmosphere on average; the rest was absorbed by carbon sinks on land and in the oceans. In the past 50 years, the fraction of CO2 emissions that remains in the atmosphere each year has likely increased, from about 40% to 45%, and models suggest that this trend was caused by a decrease in the uptake of CO2 by the carbon sinks in response to climate change and variability. Changes in the CO2 sinks are highly uncertain, but they could have a significant influence on future atmospheric CO2 levels. It is therefore crucial to reduce the uncertainties.

  11. Effect of increased carbon dioxide concentrations on stratospheric ozone

    International Nuclear Information System (INIS)

    During the past several years, much attention has been focused on the destruction of ozone by anthropogenic pollutants such as the nitrogen oxides and chlorofluoromethane. Little or no attention has been given to the influence on ozone of an increased carbon dioxide concentration for which a measurable growth has been observed. Increased carbon dioxide can directly affect ozone by perturbing atmospheric temperatures, which will alter ozone production, whose rate displays a fairly strong temperature dependence. This paper presents one-dimensional model results for the steady state ozone behavior when the CO2 concentration is twice its ambient level which account for coupling between chemistry and temperature. When the CO2 level doubled, the total ozone burden increased in relation to the ambient burden by 1.2--2.5%, depending on the vertical diffusion coefficient used. Above 30 km. In this region the relation variations were insensitive to the choice of diffusion coefficient. Below 30 km, ozone concentrations were smaller than the unperturbed values and were sensitive to the vertical diffusion profile in this region (10--30 km). Ozone decreases in the lower stratosphere because of a reduction in ozone-producing solar radiation, which results in smaller downward ozone fluxes from the region at 25--30 km relative to the flux values for the ambient atmosphere. These offsetting changes occurring in the upper and lower stratosphere act to minimize the variation in total ozone

  12. Alteration of Oceanic Nitrification Under Elevated Carbon Dioxide Concentrations

    Science.gov (United States)

    Beman, J.; Chow, C. E.; Popp, B. N.; Fuhrman, J. A.; Feng, Y.; Hutchins, D. A.

    2008-12-01

    Atmospheric carbon dioxide (CO2) concentrations are increasing exponentially and expected to double by the year 2100. Dissolution of excess CO2 in the upper ocean reduces pH, alters carbonate chemistry, and also represents a potential resource for autotrophic organisms that convert inorganic carbon into biomass--including a broad spectrum of marine microbes. These bacteria and archaea drive global biogeochemical cycles of carbon and nitrogen and constitute the vast majority of biomass in the sea, yet their responses to reduced pH and increased pCO2 remain largely undocumented. Here we show that elevated pCO2 may sharply reduce nitrification rates and populations of nitrifying microorganisms in the ocean. Multiple experiments were performed in the Sargasso Sea and the Southern California Bight under glacial maximum (193 ppm), present day (390 ppm), and projected (750 ppm) pCO2 concentrations, over time scales from hours to multiple days, and at depths of 45 m to 240 m. Measurement of nitrification rates using isotopically-labeled nitrogen showed 2-5 fold reduction under elevated pCO2--as well as an increase under glacial maximum pCO2. Marine Crenarchaeota are likely involved in nitrification as ammonia-oxidizing archaea (AOA) and are among the most abundant microbial groups in the ocean, yet this group decreased by 40-80% under increased pCO2, based on quantification of both 16S rRNA and ammonia monooxygenase (amoA) gene copies. Crenarchaeota also steadily declined over the course of multiple days under elevated pCO2, whereas ammonia-oxidizing (AOB) and nitrite-oxidizing bacteria (NOB) were more variable in their responses or were not detected. These findings suggest that projected increases in pCO2 and subsequent decreases in pH may strongly influence marine biogeochemistry and microbial community structure in the sea.

  13. Black carbon concentration trends in Helsinki during 1996–2005

    Directory of Open Access Journals (Sweden)

    T. Pakkanen

    2007-10-01

    Full Text Available The black carbon (BC concentration trends were studied during ten years in Helsinki, Finland. Measurements were made in three campaigns between 1996 and 2005 at an urban area locating two kilometres from the centre of Helsinki. The first campaign was from November 1996 to June 1997, the second from September 2000 to May 2001 and the third from March 2004 to October 2005. In this study, only data from winter and spring months was analysed. The effect of traffic and meteorological variables on the measured BC concentrations was studied by means of a multiple regression analysis, where the meteorological data was obtained from a meteorological pre-processing model (MPP-FMI. During the ten years, the campaign median BC concentrations were found to decrease slightly from 1.11 to 1.00 μg m−3. The lowest campaign median concentration (0.93 μg m−3 was measured during the second campaign in 2000–2001, when also the lowest traffic rates were measured. The strongest decrease between campaigns 1 and 3 was observed during weekday daytimes, when the traffic rates are highest. The variables affecting the measured BC concentrations most were traffic, wind speed and mixing height. On weekdays, traffic had clearly the most important influence and on weekends the effect of wind speed diluted the effect of traffic. The affecting variables and their influence on the BC concentration were similar in winter and spring. The separate examination of the three campaigns showed that the effect of traffic on the BC concentrations had decreased during the studied years. This reduction was caused by cleaner emissions from vehicles, since between years 1996 and 2005 the traffic rates had increased. A rough estimate gave that vehicle number-scaled BC mass concentrations have decreased from 0.0028 to 0.0020 μg m−3 between campaigns 1 and 3.

  14. Organic carbon concentrations and stocks in Romanian mineral forest soils

    Directory of Open Access Journals (Sweden)

    Lucian C. Dincă

    2012-12-01

    Full Text Available Estimating soils organic carbon stock and its change in time is an actual concern for scientists and climate change policy makers. The present article firstly focus on determination of C stocks in Romania on forest soil types, as well as development of the spatial distribution mapping using a Geographic Information System (GIS and also the secondly on the quantification of uncertainty associated with currently available data on C concentration on forest soils geometrical layers. Determination of C stock was done based on forest management plans database created over 2000-2006. Unlike original database, the data for this study was harmonized on following depths: 0-10 cm, 10-20 cm, 20-40 cm, and > 40 cm. Then, the obtained values were grouped by soil types, resulting average values for the main forest soils from Romania. A soil area weighted average value of 137 t/ha is calculated for Romania, in the range of estimations for other European geographic and climatic areas. The soils that have the largest amount of organic carbon are andosols, vertisols, entic and haplic podzols, whereas the ones that have the smallest values of organic carbon are solonetz and solonchaks. Although current assessment relies on very large number of samples from the forest management planning database, the variability of C concentration remains very large, ~40-50% for coefficient the variation and ~100% of the average, when defining the range of 95% of entire soil population, rather showing the variability than uncertainty of the average estimated. Best fit for C concentration on geometric layers in any forest soil is asymmetric, associated with log-normal distributions.

  15. Development and evaluation of a daily temporal interpolation model for fine particulate matter species concentrations and source apportionment

    Science.gov (United States)

    Redman, Jeremiah D.; Holmes, Heather A.; Balachandran, Sivaraman; Maier, Marissa L.; Zhai, Xinxin; Ivey, Cesunica; Digby, Kyle; Mulholland, James A.; Russell, Armistead G.

    2016-09-01

    The impacts of emissions sources on air quality in St. Louis, Missouri are assessed for use in acute health effects studies. However, like many locations in the United States, the speciated particulate matter (PM) measurements from regulatory monitoring networks in St. Louis are only available every third day. The power of studies investigating acute health effects of air pollution is reduced when using one-in-three day source impacts compared to daily source impacts. This paper presents a temporal interpolation model to estimate daily speciated PM2.5 mass concentrations and source impact estimates using one-in-three day measurements. The model is used to interpolate 1-in-3 day source impact estimates and to interpolate the 1-in-3 day PM species concentrations prior to source apportionment (SA). Both approaches are compared and evaluated using two years (June 2001-May 2003) of daily data from the St. Louis Midwest Supersite (STL-SS). Data withholding is used to simulate a 1-in-3 day data set from the daily data to evaluate interpolated estimates. After evaluation using the STL-SS data, the model is used to estimate daily source impacts at another site approximately seven kilometers (7 km) northwest of the STL-SS (Blair); results between the sites are compared. For interpolated species concentrations, the model performs better for secondary species (sulfate, nitrate, ammonium, and organic carbon) than for primary species (metals and elemental carbon), likely due to the greater spatial autocorrelation of secondary species. Pearson correlation (R) values for sulfate, nitrate, ammonium, elemental carbon, and organic carbon ranged from 0.61 (elemental carbon, EC2) to 0.97 (sulfate). For trace metals, the R values ranged from 0.31 (Ba) to 0.81 (K). The interpolated source impact estimates also indicated a stronger correlation for secondary sources. Correlations of the secondary source impact estimates based on measurement data and interpolation data ranged from 0.68 to 0

  16. Effect of Varying Inert Gas and Acetylene Concentration on the Synthesis of Carbon Nanotubes.

    Science.gov (United States)

    Afrin, Rahat; Abbas, Syed Mustansar; Shah, Nazar Abbas; Mustafa, Muhammad Farooq; Ali, Zulfiqar; Ahmad, Nisar

    2016-03-01

    The multiwalled carbon nanotubes (MWCNTs) with small diameter and high purity were achieved by chemical vapor deposition technique using silicon substrate. The introduction of specific concentration of inert gas with hydrocarbon played a key role in controlling morphology and diameter of MWCNTs. Nickel mixed ferrite nanoparticles were used as a catalyst for the growth of MWCNTs. Growth parameters like concentration of hydrocarbon source and inert gas flow, composition of catalyst particles and growth temperature were studied. In this work smaller diameter and twisted MWCNTs were formed by dilution of acetylene with argon gas. Electrical properties suggest a semimetallic behavior of synthesized MWCNTs.

  17. An analysis of continuous black carbon concentrations in proximity to an airport and major roadways

    Science.gov (United States)

    Dodson, Robin E.; Andres Houseman, E.; Morin, Barbara; Levy, Jonathan I.

    Black carbon (BC), a constituent of particulate matter, is emitted from multiple combustion sources, complicating determination of contributions from individual sources or source categories from monitoring data. In close proximity to an airport, this may include aircraft emissions, other emissions on the airport grounds, and nearby major roadways, and it would be valuable to determine the factors most strongly related to measured BC concentrations. In this study, continuous BC concentrations were measured at five monitoring sites in proximity to a small regional airport in Warwick, Rhode Island from July 2005 to August 2006. Regression was used to model the relative contributions of aircraft and related sources, using real-time flight activity (departures and arrivals) and meteorological data, including mixing height, wind speed and direction. The latter two were included as a nonparametric smooth spatial term using thin-plate splines applied to wind velocity vectors and fit in a linear mixed model framework. Standard errors were computed using a moving-block bootstrap to account for temporal autocorrelation. Results suggest significant positive associations between hourly departures and arrivals at the airport and BC concentrations within the community, with departures having a more substantial impact. Generalized Additive Models for wind speed and direction were consistent with significant contributions from the airport, major highway, and multiple local roads. Additionally, inverse mixing height, temperature, precipitation, and at one location relative humidity, were associated with BC concentrations. Median contribution estimates indicate that aircraft departures and arrivals (and other sources coincident in space and time) contribute to approximately 24-28% of the BC concentrations at the monitoring sites in the community. Our analysis demonstrated that a regression-based approach with detailed meteorological and source characterization can provide insights

  18. Black carbon and elemental concentration of ambient particulate matter in Makassar Indonesia

    International Nuclear Information System (INIS)

    Airborne particulate matter with aerodynamic diameter of less or equal to 10 um or PM10, has been collected on a weekly basis for one year from February 2012 to January 2013 at one site of Makassar, Province of South Sulawesi Indonesia. The samples were collected using a size selective high volume air sampler sited at Daya, a mixed urban, commercial and industrial area in the city of Makassar. The concentration of black carbon (BC) along with a total of 14 elements (i.e Al, Ba, Ca, Cr, Fe, K, Mg, Ba, Na, Ni, Pb, Si, Ti and Zn) were determined from the sample. Results showed that the average particulate mass concentration was 32.9 ± 11.6 μg/m3 with BC and elemental concentration constituted 6.1% and 10.6% of the particulate concentration, respectively. Both BC and elemental constituents contributed 16.7% while 83.3% of the particulate matter remained to be counted for. The black carbon concentration was higher during the dry months which may be attributed to rampant biomass burning during hot and dry weather conditions, apart from other possible sources. Most of the elements were enriched relative to soil origin illustrating of their possible associations with other sources such as marine and anthropogenic derived aerosols, particularly Cr, Ni, Pb, and Zn, which are known to originate from man-made activities

  19. Natural variability in the surface ocean carbonate ion concentration

    Directory of Open Access Journals (Sweden)

    N. S. Lovenduski

    2015-11-01

    Full Text Available We investigate variability in the surface ocean carbonate ion concentration ([CO32−] on the basis of a~long control simulation with an Earth System Model. The simulation is run with a prescribed, pre-industrial atmospheric CO2 concentration for 1000 years, permitting investigation of natural [CO32−] variability on interannual to multi-decadal timescales. We find high interannual variability in surface [CO32−] in the tropical Pacific and at the boundaries between the subtropical and subpolar gyres in the Northern Hemisphere, and relatively low interannual variability in the centers of the subtropical gyres and in the Southern Ocean. Statistical analysis of modeled [CO32−] variance and autocorrelation suggests that significant anthropogenic trends in the saturation state of aragonite (Ωaragonite are already or nearly detectable at the sustained, open-ocean time series sites, whereas several decades of observations are required to detect anthropogenic trends in Ωaragonite in the tropical Pacific, North Pacific, and North Atlantic. The detection timescale for anthropogenic trends in pH is shorter than that for Ωaragonite, due to smaller noise-to-signal ratios and lower autocorrelation in pH. In the tropical Pacific, the leading mode of surface [CO32−] variability is primarily driven by variations in the vertical advection of dissolved inorganic carbon (DIC in association with El Niño–Southern Oscillation. In the North Pacific, surface [CO32−] variability is caused by circulation-driven variations in surface DIC and strongly correlated with the Pacific Decadal Oscillation, with peak spectral power at 20–30-year periods. North Atlantic [CO32−] variability is also driven by variations in surface DIC, and exhibits weak correlations with both the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation. As the scientific community seeks to detect the anthropogenic influence on ocean carbonate chemistry, these results

  20. Enhanced biological nutrient removal in modified carbon source division anaerobic anoxic oxic process with return activated sludge pre-concentration☆

    Institute of Scientific and Technical Information of China (English)

    Qin Lu; Haiyan Wu; Haoyan Li; Dianhai Yang

    2015-01-01

    A pilot-scale modified carbon source division anaerobic anoxic oxic (AAO) process with pre-concentration of returned activated sludge (RAS) was proposed in this study for the enhanced biological nutrient removal (BNR) of municipal wastewater with limited carbon source. The influent carbon source was fed in step while a novel RAS pre-concentration tank was adopted to improve BNR efficiency, and the effects of an influent carbon source distribution ratio and a RAS pre-concentration ratio were investigated. The results show that the removal efficiency of TN is mainly influenced by the carbon source distribution ratio while the TP removal relies on the RAS pre-concentration ratio. The optimum carbon source distribution ratio and RAS pre-concentration ratio are 60%and 50%, respectively, with an inner recycling ratio of 100%under the optimum steady operation of pilot test, reaching an average effluent TN concentration of 9.8 mg·L−1 with a removal efficiency of 63%and an average TP removal efficiency of 94%. The mechanism of nutrient removal is discussed and the kinetics is analyzed. The results reveal that the optimal carbon source distribution ratio provides sufficient denitrifying carbon source to each anoxic phase, reducing nitrate accumulation while the RAS pre-concentration ratio improves the condition of anaerobic zone to ensure the phosphorus release due to less nitrate in the returned sludge. Therefore, nitrifying bacteria, denitrifying bacteria and phosphorus accumulation organisms play an important role under the optimum condition, enhancing the performance of nutrient removal in this test.

  1. The source of carbon dioxide for gastric acid production.

    Science.gov (United States)

    Steer, Howard

    2009-01-01

    The source of carbon dioxide for the chemical reaction leading to the production of gastric acid is unknown. The decarboxylation of an amino acid releases carbon dioxide. Pepsinogens provide a rich source of the amino acid arginine. Both the source of carbon dioxide, arginine, and the consequence of arginine decarboxylation, agmatine, have been studied. The site of carbon dioxide production has been related to the survival of the parietal cell. An immunohistochemical study has been carried out on glycol methacrylate embedded gastric biopsies from the normal stomach of 38 adult patients. The sections have been stained using polyclonal antibody to pepsinogen II, polyclonal antibody to agmatine, and polyclonal antibody to Helicobacter pylori. Pepsinogen II and agmatine are found in the parietal cell canaliculi. This is consistent with the production of carbon dioxide from arginine in the parietal cell canaliculi. Evidence is presented for the decarboxylation of arginine derived from the activation segment of pepsinogen as the source of carbon dioxide for the production of gastric acid. The production of carbon dioxide by the decarboxylation of arginine in the parietal cell canaliculus enables the extracellular hydration of carbon dioxide at the known site of carbonic anhydrase activity. The extracellular production of acid in the canaliculus together with the presence of agmatine helps to explain why the parietal cells are not destroyed during the formation of gastric acid. Agmatine is found in the mucus secreting cells of the stomach and its role in acid protection of the stomach is discussed. Anat Rec, 2009. (c) 2008 Wiley-Liss, Inc. PMID:18951509

  2. Proteomic analysis of carbon concentrating chemolithotrophic bacteria Serratia sp. for sequestration of carbon dioxide.

    Directory of Open Access Journals (Sweden)

    Randhir K Bharti

    Full Text Available A chemolithotrophic bacterium enriched in the chemostat in presence of sodium bicarbonate as sole carbon source was identified as Serratia sp. by 16S rRNA sequencing. Carbon dioxide sequestering capacity of bacterium was detected by carbonic anhydrase enzyme and ribulose-1, 5- bisphosphate carboxylase/oxygenase (RuBisCO. The purified carbonic anhydrase showed molecular weight of 29 kDa. Molecular weight of RuBisCO was 550 kDa as determined by fast protein liquid chromatography (FPLC, however, sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE showed presence of two subunits whose molecular weights were 56 and 14 kDa. The Western blot analysis of the crude protein and purified sample cross reacted with RuBisCO large-subunit polypeptides antibodies showed strong band pattern at molecular weight around 56 kDa regions. Whole cell soluble proteins of Serratia sp. grown under autotrophic and heterotrophic conditions were resolved by two-dimensional gel electrophoresis and MALDI-TOF/MS for differential expression of proteins. In proteomic analysis of 63 protein spots, 48 spots were significantly up-regulated in the autotrophically grown cells; seven enzymes showed its utilization in autotrophic carbon fixation pathways and other metabolic activities of bacterium including lipid metabolisms indicated sequestration potency of carbon dioxide and production of biomaterials.

  3. Role of metabolite transporters in source-sink carbon allocation

    OpenAIRE

    Ludewig, Frank; Flügge, Ulf-Ingo

    2013-01-01

    Plants assimilate carbon dioxide during photosynthesis in chloroplasts. Assimilated carbon is subsequently allocated throughout the plant. Generally, two types of organs can be distinguished, mature green source leaves as net photoassimilate exporters, and net importers, the sinks, e.g., roots, flowers, small leaves, and storage organs like tubers. Within these organs, different tissue types developed according to their respective function, and cells of either tissue type are highly compartme...

  4. Role of metabolite transporters in source-sink carbon allocation

    OpenAIRE

    Frank eLudewig; Ulf-Ingo eFlügge

    2013-01-01

    Plants assimilate carbon dioxide during photosynthesis in chloroplasts. Assimilated carbon is subsequently allocated throughout the plant. Generally, two types of organs can be distinguished, mature green source leaves as net photoassimilate exporters, and net importers, the sinks, e.g. roots, flowers, small leaves and storage organs like tubers. Within these organs, different tissue types developed according to their respective function, and cells of either tissue type are highly compartment...

  5. Concentrations, sources and geochemistry of airborne particulate matter at a major European airport.

    Science.gov (United States)

    Amato, Fulvio; Moreno, Teresa; Pandolfi, Marco; Querol, Xavier; Alastuey, Andrés; Delgado, Ana; Pedrero, Manuel; Cots, Nuria

    2010-04-01

    Monitoring of aerosol particle concentrations (PM(10), PM(2.5), PM(1)) and chemical analysis (PM(10)) was undertaken at a major European airport (El Prat, Barcelona) for a whole month during autumn 2007. Concentrations of airborne PM at the airport were close to those at road traffic hotspots in the nearby Barcelona city, with means measuring 48 microg PM(10)/m(3), 21 microg PM(2.5)/m(3) and 17 microg PM(1)/m(3). Meteorological controls on PM at El Prat are identified as cleansing daytime sea breezes with abundant coarse salt particles, alternating with nocturnal land-sourced winds which channel air polluted by industry and traffic (PM(1)/PM(10) ratios > 0.5) SE down the Llobregat Valley. Chemical analyses of the PM(10) samples show that crustal PM is dominant (38% of PM(10)), followed by total carbon (OC + EC, 25%), secondary inorganic aerosols (SIA, 20%), and sea salt (6%). Local construction work for a new airport terminal was an important contributor to PM(10) crustal levels. Source apportionment modelling PCA-MLRA identifies five factors: industrial/traffic, crustal, sea salt, SIA, and K(+) likely derived from agricultural biomass burning. Whereas most of the atmospheric contamination concerning ambient air PM(10) levels at El Prat is not attributable directly to aircraft movement, levels of carbon are unusually high (especially organic carbon), as are metals possibly sourced from tyre detritus/smoke in runway dust (Ba, Zn, Mo) and from brake dust in ambient PM(10) (Cu, Sb), especially when the airport is at its most busy. We identify microflakes of aluminous alloys in ambient PM(10) filters derived from corroded fuselage and wings as an unequivocal and highly distinctive tracer for aircraft movement. PMID:20383366

  6. Natural variability in the surface ocean carbonate ion concentration

    Directory of Open Access Journals (Sweden)

    N. S. Lovenduski

    2015-08-01

    Full Text Available We investigate variability in the surface ocean carbonate ion concentration ([CO32−] on the basis of a long control simulation with a fully-coupled Earth System Model. The simulation is run with a prescribed, pre-industrial atmospheric CO2 concentration for 1000 years, permitting investigation of natural [CO32−] variability on interannual to multi-decadal timescales. We find high interannual variability in surface [CO32−] in the tropical Pacific and at the boundaries between the subtropical and subpolar gyres in the Northern Hemisphere, and relatively low interannual variability in the centers of the subtropical gyres and in the Southern Ocean. Statistical analysis of modeled [CO32−] variance and autocorrelation suggests that significant anthropogenic trends in the saturation state of aragonite (Ωaragonite are already or nearly detectable at the sustained, open-ocean timeseries sites, whereas several decades of observations are required to detect anthropogenic trends in Ωaragonite in the tropical Pacific, North Pacific, and North Atlantic. The detection timescale for anthropogenic trends in pH is shorter than that for Ωaragonite, due to smaller noise-to-signal ratios and lower autocorrelation in pH. In the tropical Pacific, the leading mode of surface [CO32−] variability is primarily driven by variations in the vertical advection of dissolved inorganic carbon (DIC in association with El Niño–Southern Oscillation. In the North Pacific, surface [CO32−] variability is caused by circulation-driven variations in surface DIC and strongly correlated with the Pacific Decadal Oscillation, with peak spectral power at 20–30 year periods. North Atlantic [CO32−] variability is also driven by variations in surface DIC, and exhibits weak correlations with both the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation. As the scientific community seeks to detect the anthropogenic influence on ocean carbonate chemistry, these

  7. Relation between coal aromatic carbon concentration and proximate analysis fixed carbons

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, P.R.

    1981-01-01

    Good agreement has been obtained between measured proximate analysis values for fixed carbon (FC) and the predictions of a thermal decomposition model. The model provides a basis for understanding the relation between FC and coal structure and between FC measured under proximate analysis conditions and coke or char measured in other thermal decomposition experiments. The key parameters in the model are the aromatic carbon concentration (C/sub ar/) and the tar yield. C/sub ar/ has been determined for 43 coals using quantitative infrared analysis. The aliphatic hydrogen concentration is measured from the absorption near 2900 cm/sub -1/ and the aliphatic carbon concentration is computed assuming a stoichiometry of CH/sub 1/./sub 8/. C/sub ar/ is then computed by difference. The results verify the good correlation between C/sub ar/ and FC discussed by van Krevelen. To explain this correlation, use has been made of a coal thermal decomposition model which has been successful in simulating the quantity and composition of volatile components yielded under vacuum pyrolysis conditions. To apply the model to proximate analysis, it was necessary to estimate the tar yields obtained with thick beds and the amounts of O, N, H, and S which remain with the FC. The tar yields for proximate analysis conditions have been estimated to be 1/3 to 1/4 the yields for thin beds in vacuum. To determine the composition of the FC, measurements were made on a lignite and a bituminous char produced in a thin bed heated by a wire grid for the time (7 min) and temperature (950 C) used in the proximate analysis, and on the FC residues from a proximate analysis volatile matter determination. Both residues give similar results, showing that approximately 10% of the 'fixed carbon' is not carbon. Values of FC computed with the model adjusted for the above conditions are in good agreement with the measured values. 25 refs.

  8. Impacts of CO2 concentration on growth, lipid accumulation, and carbon-concentrating-mechanism-related gene expression in oleaginous Chlorella.

    Science.gov (United States)

    Fan, Jianhua; Xu, Hui; Luo, Yuanchan; Wan, Minxi; Huang, Jianke; Wang, Weiliang; Li, Yuanguang

    2015-03-01

    Biodiesel production by microalgae with photosynthetic CO2 biofixation is thought to be a feasible way in the field of bioenergy and carbon emission reduction. Knowledge of the carbon-concentrating mechanism plays an important role in improving microalgae carbon fixation efficiency. However, little information is available regarding the dramatic changes of cells suffered upon different environmental factors, such as CO2 concentration. The aim of this study was to investigate the growth, lipid accumulation, carbon fixation rate, and carbon metabolism gene expression under different CO2 concentrations in oleaginous Chlorella. It was found that Chlorella pyrenoidosa grew well under CO2 concentrations ranging from 1 to 20 %. The highest biomass and lipid productivity were 4.3 g/L and 107 mg/L/day under 5 % CO2 condition. Switch from high (5 %) to low (0.03 %, air) CO2 concentration showed significant inhibitory effect on growth and CO2 fixation rate. The amount of the saturated fatty acids was increased obviously along with the transition. Low CO2 concentration (0.03 %) was suitable for the accumulation of saturated fatty acids. Reducing the CO2 concentration could significantly decrease the polyunsaturated degree in fatty acids. Moreover, the carbon-concentrating mechanism-related gene expression revealed that most of them, especially CAH2, LCIB, and HLA3, had remarkable change after 1, 4, and 24 h of the transition, which suggests that Chlorella has similar carbon-concentrating mechanism with Chlamydomonas reinhardtii. The findings of the present study revealed that C. pyrenoidosa is an ideal candidate for mitigating CO2 and biodiesel production and is appropriate as a model for mechanism research of carbon sequestration.

  9. Chemoselective Synthesis of Carbamates using CO2 as Carbon Source.

    Science.gov (United States)

    Riemer, Daniel; Hirapara, Pradipbhai; Das, Shoubhik

    2016-08-01

    Synthesis of carbamates directly from amines using CO2 as the carbon source is a straightforward and sustainable approach. Herein, we describe a highly effective and chemoselective methodology for the synthesis of carbamates at room temperature and atmospheric pressure. This methodology can also be applied to protect the amino group in amino acids and peptides, and also to synthesize important pharmaceuticals. PMID:27376902

  10. Sources of uncertainties in modelling black carbon at the global scale

    Directory of Open Access Journals (Sweden)

    E. Vignati

    2010-03-01

    Full Text Available Our understanding of the global black carbon (BC cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and those due to the uncertainties in the definition and quantification of the observations, which propagate through to both the emission inventories, and the measurements used for the model evaluation.

    The schemes for the atmospheric processing of black carbon that have been tested with the model are (i a simple approach considering BC as bulk aerosol and a simple treatment of the removal with fixed 70% of in-cloud black carbon concentrations scavenged by clouds and removed when rain is present and (ii a more complete description of microphysical ageing within an aerosol dynamics model, where removal is coupled to the microphysical properties of the aerosol, which results in a global average of 40% in-cloud black carbon that is scavenged in clouds and subsequently removed by rain, thus resulting in a longer atmospheric lifetime. This difference is reflected in comparisons between both sets of modelled results and the measurements. Close to the sources, both anthropogenic and vegetation fire source regions, the model results do not differ significantly, indicating that the emissions are the prevailing mechanism determining the concentrations and the choice of the aerosol scheme does not influence the levels. In more remote areas such as oceanic and polar regions the differences can be orders of magnitude, due to the differences between the two schemes. The more complete description reproduces the seasonal trend of the black carbon observations in those areas, although not always the magnitude of the signal, while the more simplified approach underestimates black carbon concentrations by orders of

  11. Silica-Based Carbon Source Delivery for In-situ Bioremediation Enhancement

    Science.gov (United States)

    Zhong, L.; Lee, M. H.; Lee, B.; Yang, S.

    2015-12-01

    Colloidal silica aqueous suspensions undergo viscosity increasing and gelation over time under favorable geochemical conditions. This property of silica suspension can potentially be applied to deliver remedial amendments to the subsurface and establish slow release amendment sources for enhanced remediation. In this study, silica-based delivery of carbon sources for in-situ bioremediation enhancement is investigated. Sodium lactate, vegetable oil, ethanol, and molasses have been studied for the interaction with colloidal silica in aqueous suspensions. The rheological properties of the carbon source amendments and silica suspension have been investigated. The lactate-, ethanol-, and molasses-silica suspensions exhibited controllable viscosity increase and eventually became gels under favorable geochemical conditions. The gelation rate was a function of the concentration of silica, salinity, amendment, and temperature. The vegetable oil-silica suspensions increased viscosity immediately upon mixing, but did not perform gelation. The carbon source release rate from the lactate-, ethanol-, and molasses-silica gels was determined as a function of silica, salinity, amendment concentration. The microbial activity stimulation and in-situ bioremediation enhancement by the slow-released carbon from the amendment-silica gels will be demonstrated in future investigations planned in this study.

  12. Sources of uncertainties in modelling Black Carbon at the global scale

    Directory of Open Access Journals (Sweden)

    F. Cavalli

    2009-11-01

    Full Text Available Our understanding of the global black carbon cycle is essentially qualitative due to uncertainties in our knowledge of the properties of black carbon. This work investigates uncertainties related to modelling black carbon: due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and due to the uncertainties in the definition and quantification of observed black carbon, which propagate through to both the emission inventories, and the measurements used for the model evaluation.

    The schemes for the atmospheric processing of black carbon that have been tested with the model are (i a simple approach considering black carbon as bulk aerosol and a simple treatment in the removal and (ii a more complete description of microphysical aging within an aerosol dynamics model, where removal is coupled to the microphysical properties of the aerosol. In the first approach a fixed 70% of black carbon is scavenged in clouds and removed when rain is present. The second leads to a global average of 40% black carbon that is scavenged in clouds and subsequently removed by rain, thus resulting in a longer lifetime. This difference is reflected in comparisons between both sets of modelled results and the measurements. Close to the sources, both anthropogenic and vegetation fire source regions, the model results do not differ significantly, showing that the emissions are the prevailing mechanism determining the concentrations and the choice of the aerosol scheme does not influence the levels. In more remote areas such as oceanic and polar regions the differences can be orders of magnitude, due to the differences between the two schemes. The more complete description reproduces the seasonal trend of the black carbon observations in those areas, although not always the magnitude of the signal, while the more simplified approach underestimates black carbon concentrations by orders of magnitude.

  13. Comparative study on CO2 sources in soil developed on carbonate rock and non-carbonate rock in Central Guizhou

    Institute of Scientific and Technical Information of China (English)

    黎廷宇; 王世杰; 郑乐平

    2002-01-01

    In this paper, by using concentration and carbon stable isotope the CO2 sources of soil profiles developed on limestone, dolostone and claystone basements in Central Guizhou, China are comparatively studied. The results show that CO2 concentration of soil profiles developed on different basements is different, having the following sequence: limestone>dolostone>claystone. Below the soil depth of 20 cm from the surface the ? 13C value of CO2 in soil profile developed on limestone ranges from -12.811‰ - -13.492‰(PDB), that in soil profile developed on dolostone varys from -13.212‰ - -14.271‰(PDB) and that in soil profile developed on claystone is about -20.234‰ - -21.485‰(PDB). Taking the carbon isotope of soil organic matter and carbonate rock as two isotopic endmembers, the proportion of soil CO2 generated by dissolution of carbonate rock is calculated, about 21%-25% for soil profile developed on limestone basement, 19%-21% for soil profile developed on dolostone basement. There is almost no influx of CO2 generated by the dissolution of carbonate rock in soil profile developed on claystone basement.

  14. Seasonal variations in concentration and composition of dissolved organic carbon in Tokyo Bay

    Directory of Open Access Journals (Sweden)

    A. Kubo

    2014-07-01

    Full Text Available Concentrations of recalcitrant and bioavailable dissolved organic carbon (DOC and their seasonal variations were investigated at three stations in Tokyo Bay, Japan, and in two freshwater sources flowing into the bay to evaluate the significance of DOC degradation for the carbon budget in coastal waters and carbon export to the open ocean. Recalcitrant DOC (RDOC was differentiated from bioavailable DOC (BDOC as a remnant of DOC after 150 days of bottle incubation. On average, RDOC accounted for 78% of the total DOC in Shibaura sewage treatment plant (STP effluent, 67% in the upper Arakawa River water, 66% in the lower Arakawa River water, and 78% in surface bay water. RDOC concentrations were higher than BDOC at all stations. In freshwater environments, RDOC concentrations were almost constant throughout the year. In the bay, RDOC was higher during spring and summer than during autumn and winter. The relative abundance of RDOC in the bay derived from phytoplankton, terrestrial, and open oceanic waters was estimated to be 9%, 33%, and 58%, respectively, by multiple regression analysis of RDOC, salinity, and chl a. In addition, comparison with previous data from 1972 revealed that concentrations of RDOC and BDOC have decreased by 33% and 74% at freshwater sites and 39% and 76% at Tokyo Bay, while the ratio of RDOC to DOC has increased. The change in DOC concentration and composition was probably due to increased amounts of sewage treatment plant effluent entering the system. Tokyo Bay exported DOC, mostly RDOC, to the open ocean because of remineralization of BDOC.

  15. Photoautotrophic microorganisms as a carbon source for temperate soil invertebrates.

    Science.gov (United States)

    Schmidt, Olaf; Dyckmans, Jens; Schrader, Stefan

    2016-01-01

    We tested experimentally if photoautotrophic microorganisms are a carbon source for invertebrates in temperate soils. We exposed forest or arable soils to a (13)CO2-enriched atmosphere and quantified (13)C assimilation by three common animal groups: earthworms (Oligochaeta), springtails (Hexapoda) and slugs (Gastropoda). Endogeic earthworms (Allolobophora chlorotica) and hemiedaphic springtails (Ceratophysella denticulata) were highly (13)C enriched when incubated under light, deriving up to 3.0 and 17.0%, respectively, of their body carbon from the microbial source in 7 days. Earthworms assimilated more (13)C in undisturbed soil than when the microbial material was mixed into the soil, presumably reflecting selective surface grazing. By contrast, neither adult nor newly hatched terrestrial slugs (Deroceras reticulatum) grazed on algal mats. Non-photosynthetic (13)CO2 fixation in the dark was negligible. We conclude from these preliminary laboratory experiments that, in addition to litter and root-derived carbon from vascular plants, photoautotrophic soil surface microorganisms (cyanobacteria, algae) may be an ecologically important carbon input route for temperate soil animals that are traditionally assigned to the decomposer channel in soil food web models and carbon cycling studies. PMID:26740559

  16. Quantifying global terrestrial carbon influx and storage as stimulated by an increase in atmospheric carbon dioxide concentration

    OpenAIRE

    Luo, Yiqi

    1997-01-01

    EXTRACT (SEE PDF FOR FULL ABSTRACT): Measurements of spatial and temporal distributions of carbon dioxide concentration and carbon-13/carbon-12 ratio in the atmosphere suggest a strong biospheric carbon sink in terrestrial ecosystems. Quantifying the sink, however, has become an enormous challenge for Earth system scientists because of great uncertainties associated with biological variation and environmental heterogeneity in the ecosystems. This paper presents an approach that uses two d...

  17. Concentrations of polycyclic aromatic hydrocarbons in New York City community garden soils: Potential sources and influential factors.

    Science.gov (United States)

    Marquez-Bravo, Lydia G; Briggs, Dean; Shayler, Hannah; McBride, Murray; Lopp, Donna; Stone, Edie; Ferenz, Gretchen; Bogdan, Kenneth G; Mitchell, Rebecca G; Spliethoff, Henry M

    2016-02-01

    A total of 69 soil samples from 20 community gardens in New York City (New York, USA) were collected and analyzed for 23 polycyclic aromatic hydrocarbons (PAHs) and black carbon. For each garden, samples were collected from nongrowing areas (non-bed) and from vegetable-growing beds, including beds with and without visible sources of PAHs. The sum of the US Environmental Protection Agency's 16 priority PAHs ranged up to 150 mg/kg, and the median (5.4 mg/kg) and mean (14.2 mg/kg) were similar to those previously reported for urban areas in the northeast United States. Isomer ratios indicated that the main sources of PAHs were petroleum, coal, and wood combustion. The PAH concentrations were significantly and positively associated with black carbon and with modeled air PAH concentrations, suggesting a consistent relationship between historical deposition of atmospheric carbon-adsorbed PAHs and current PAH soil concentrations. Median PAH soil concentration from non-bed areas was higher (7.4 mg/kg) than median concentration from beds in the same garden (4.0 mg/kg), and significantly higher than the median from beds without visible sources of PAHs (3.5 mg/kg). Median PAH concentration in beds from gardens with records of soil amendments was 58% lower compared with beds from gardens without those records. These results suggest that gardening practices in garden beds without visible sources of PAHs contribute to reduce PAH soil concentrations. PMID:26636429

  18. Options for cost-effectively reducing atmospheric methane concentrations from anthropogenic biomass sources

    International Nuclear Information System (INIS)

    Methane is a major greenhouse gas, second only to carbon dioxide in its contribution to future global warming. Methane concentrations have more than doubled over the last two centuries and continue to rise annually. These increases are largely correlated with increasing human populations. Methane emissions from human related activities currently account for about 70 percent of annual emissions. Of these human related emissions, biomass sources account for about 75 percent and non-biomass sources about 25 percent. Because methane has a shorter lifetime than other major greenhouse gases, efforts to reduce methane emissions may fairly quickly be translated into lower atmospheric concentrations of methane and lower levels of radiative forcing. This fairly quick response would have the benefit of slowing the rate of climate change and hence allow natural ecosystems more time to adapt. Importantly, methane may be cost-effectively reduced from a number of biomass and non-biomass sources in the United States and worldwide. Methane is a valuable fuel, not just a waste by-product, and often systems may be reconfigured to reap the fuel value of the methane and more than justify the necessary expenditures. Such options for reducing methane emission from biomass sources exist for landfills, livestock manures, and ruminant livestock, and have been implemented to varying degrees in countries around the world. However, there are a number of barriers that hinder the more widespread use of technologies, including institutional, financial, regulatory, informational, and other barriers. This paper describes an array of available options that may be cost-effectively implemented to reduce methane emissions from biomass sources. This paper also discusses a number of programs that have been developed in the United States and internationally to promote the implementation of these methane reduction options and overcome existing barriers

  19. Concentrating Carbon Dioxide - What Do We Know from Power Plant Capture Research?

    Science.gov (United States)

    Aines, R. D.

    2014-12-01

    Geologic materials, basically calcium or magnesium-rich rocks, can provide much of the thermodynamic driving force for distributed carbon capture from air - if we can work out appropriate processes. One apparent challenge is that the rate of reaction is slower than we would like it to be. This rate is a combination of the mineralization rate (forming calcite from solution) and, since the reactions are much faster in water, the rate at which carbon dioxide can be added to solution, providing a more concentrated source of CO2(aq) for reaction. This latter problem of mass transfer across the gas-liquid interface is addressed in power plant capture schemes through increasing the chemical driving force, catalytic formation of dissolved CO2 via carbonic anhydrase and its analogues, and simple increases of surface area. An important learning from that body of research is that surface area is critically important - no amount of catalysis or chemical driving force can make up for simple transfer area. This talk will relate those learnings in power plant capture studies to the issue of accumulating CO2 to react with rocks for permanent sequestration. Not only is it important to create surface area for the reactive rocks, such as by grinding or fracturing, but it is equally valuable to increase the concentration of CO2(aq) by rapid transfer across the gas-water interface. Successful future carbon dioxide management schemes will have to take advantage of every kinetic advantage possible, in order to make good use of the thermodynamic advantage that geologic materials present for controlling atmospheric carbon levels.

  20. Methane and carbon at equilibrium in source rocks

    OpenAIRE

    Mango, Frank D

    2013-01-01

    Methane in source rocks may not exist exclusively as free gas. It could exist in equilibrium with carbon and higher hydrocarbons: CH4 + C  Hydrocarbon. Three lines of evidence support this possibility. 1) Shales ingest gas in amounts and selectivities consistent with gas-carbon equilibrium. There is a 50% increase in solid hydrocarbon mass when Fayetteville Shale is exposed to methane (450 psi) under moderate conditions (100°C): Rock-Eval S2 (mg g-1) 8.5 = > 12.5. All light hydrocarbons are i...

  1. Carbon Sources for Polyhydroxyalkanoates and an Integrated Biorefinery

    Science.gov (United States)

    Jiang, Guozhan; Hill, David J.; Kowalczuk, Marek; Johnston, Brian; Adamus, Grazyna; Irorere, Victor; Radecka, Iza

    2016-01-01

    Polyhydroxyalkanoates (PHAs) are a group of bioplastics that have a wide range of applications. Extensive progress has been made in our understanding of PHAs’ biosynthesis, and currently, it is possible to engineer bacterial strains to produce PHAs with desired properties. The substrates for the fermentative production of PHAs are primarily derived from food-based carbon sources, raising concerns over the sustainability of their production in terms of their impact on food prices. This paper gives an overview of the current carbon sources used for PHA production and the methods used to transform these sources into fermentable forms. This allows us to identify the opportunities and restraints linked to future sustainable PHA production. Hemicellulose hydrolysates and crude glycerol are identified as two promising carbon sources for a sustainable production of PHAs. Hemicellulose hydrolysates and crude glycerol can be produced on a large scale during various second generation biofuels’ production. An integration of PHA production within a modern biorefinery is therefore proposed to produce biofuels and bioplastics simultaneously. This will create the potential to offset the production cost of biofuels and reduce the overall production cost of PHAs. PMID:27447619

  2. Carbon Sources for Polyhydroxyalkanoates and an Integrated Biorefinery

    Directory of Open Access Journals (Sweden)

    Guozhan Jiang

    2016-07-01

    Full Text Available Polyhydroxyalkanoates (PHAs are a group of bioplastics that have a wide range of applications. Extensive progress has been made in our understanding of PHAs’ biosynthesis, and currently, it is possible to engineer bacterial strains to produce PHAs with desired properties. The substrates for the fermentative production of PHAs are primarily derived from food-based carbon sources, raising concerns over the sustainability of their production in terms of their impact on food prices. This paper gives an overview of the current carbon sources used for PHA production and the methods used to transform these sources into fermentable forms. This allows us to identify the opportunities and restraints linked to future sustainable PHA production. Hemicellulose hydrolysates and crude glycerol are identified as two promising carbon sources for a sustainable production of PHAs. Hemicellulose hydrolysates and crude glycerol can be produced on a large scale during various second generation biofuels’ production. An integration of PHA production within a modern biorefinery is therefore proposed to produce biofuels and bioplastics simultaneously. This will create the potential to offset the production cost of biofuels and reduce the overall production cost of PHAs.

  3. Carbon Sources for Polyhydroxyalkanoates and an Integrated Biorefinery.

    Science.gov (United States)

    Jiang, Guozhan; Hill, David J; Kowalczuk, Marek; Johnston, Brian; Adamus, Grazyna; Irorere, Victor; Radecka, Iza

    2016-01-01

    Polyhydroxyalkanoates (PHAs) are a group of bioplastics that have a wide range of applications. Extensive progress has been made in our understanding of PHAs' biosynthesis, and currently, it is possible to engineer bacterial strains to produce PHAs with desired properties. The substrates for the fermentative production of PHAs are primarily derived from food-based carbon sources, raising concerns over the sustainability of their production in terms of their impact on food prices. This paper gives an overview of the current carbon sources used for PHA production and the methods used to transform these sources into fermentable forms. This allows us to identify the opportunities and restraints linked to future sustainable PHA production. Hemicellulose hydrolysates and crude glycerol are identified as two promising carbon sources for a sustainable production of PHAs. Hemicellulose hydrolysates and crude glycerol can be produced on a large scale during various second generation biofuels' production. An integration of PHA production within a modern biorefinery is therefore proposed to produce biofuels and bioplastics simultaneously. This will create the potential to offset the production cost of biofuels and reduce the overall production cost of PHAs. PMID:27447619

  4. Carbon Sources for Yeast Growth as a Precondition of Hydrogen Peroxide Induced Hormetic Phenotype.

    Science.gov (United States)

    Vasylkovska, Ruslana; Petriv, Natalia; Semchyshyn, Halyna

    2015-01-01

    Hormesis is a phenomenon of particular interest in biology, medicine, pharmacology, and toxicology. In this study, we investigated the relationship between H2O2-induced hormetic response in S. cerevisiae and carbon sources in yeast growth medium. In general, our data indicate that (i) hydrogen peroxide induces hormesis in a concentration-dependent manner; (ii) the effect of hydrogen peroxide on yeast reproductive ability depends on the type of carbon substrate in growth medium; and (iii) metabolic and growth rates as well as catalase activity play an important role in H2O2-induced hormetic response in yeast. PMID:26843865

  5. Carbon Sources for Yeast Growth as a Precondition of Hydrogen Peroxide Induced Hormetic Phenotype

    Directory of Open Access Journals (Sweden)

    Ruslana Vasylkovska

    2015-01-01

    Full Text Available Hormesis is a phenomenon of particular interest in biology, medicine, pharmacology, and toxicology. In this study, we investigated the relationship between H2O2-induced hormetic response in S. cerevisiae and carbon sources in yeast growth medium. In general, our data indicate that (i hydrogen peroxide induces hormesis in a concentration-dependent manner; (ii the effect of hydrogen peroxide on yeast reproductive ability depends on the type of carbon substrate in growth medium; and (iii metabolic and growth rates as well as catalase activity play an important role in H2O2-induced hormetic response in yeast.

  6. Effect of Sulfur Concentration on the Morphology of Carbon Nanofibers Produced from a Botanical Hydrocarbon

    Directory of Open Access Journals (Sweden)

    Ghosh Kaushik

    2008-01-01

    Full Text Available AbstractCarbon nanofibers (CNF with diameters of 20–130 nm with different morphologies were obtained from a botanical hydrocarbon: Turpentine oil, using ferrocene as catalyst source and sulfur as a promoter by simple spray pyrolysis method at 1,000 °C. The influence of sulfur concentration on the morphology of the carbon nanofibers was investigated. SEM, TEM, Raman, TGA/DTA, and BET surface area were employed to characterize the as-prepared samples. TEM analysis confirms that as-prepared CNFs have a very sharp tip, bamboo shape, open end, hemispherical cap, pipe like morphology, and metal particle trapped inside the wide hollow core. It is observed that sulfur plays an important role to promote or inhibit the CNF growth. Addition of sulfur to the solution of ferrocene and turpentine oil mixture was found to be very effective in promoting the growth of CNF. Without addition of sulfur, carbonaceous product was very less and mainly soot was formed. At high concentration of sulfur inhibit the growth of CNFs. Hence the yield of CNFs was optimized for a given sulfur concentration.

  7. Production of Medium Chain Length Polyhydroxyalkanoates by Pseudomonas mendocina 0806 from Related and Unrelated Carbon Sources

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Pseudomonas mendocina strain 0806 isolated from oil-contaminated soil was found to produce medium chain length polyhydroxyalkanoates (mcl PHAs).The mcl PHAs consist of monomers with even numbers of carbon atoms such as hydroxyhexanoate (HHx or C6), hydroxyoctanoate (HO or C8), and/or hydroxydecanoate (HD or C10) as major compositions when the strain was grown on unrelated carbon sources such as glucose, citric acid and related carbon sources such as octanoate, myristic acid or oleic acid.While even and odd number hydroxyalkanoate (HA) monomers were synthesized when tridecanoic acid was used as carbon source.The molar ratio of carbon to nitrogen (RC/N) had strong effects on PHA compositions: the strain produced PHAs with 97%-99% (molar ratio) HD (C10) monomer when grown in a glucose ammonium sulfate medium of RC/N40.It was demonstrated that the molar ratio of HO/HD remained constant in the polymers synthesized from media containing a constant RC/N, regardless of the change of glucose concentration.Up to 3.6 g/L cell dry weight containing 45% (mass fraction) PHAs was produced by the strain grown for 48 h in a medium containing 25 g/L glucose with RC/N of 40.

  8. Fine and ultrafine particulate organic carbon in the Los Angeles basin: Trends in sources and composition.

    Science.gov (United States)

    Shirmohammadi, Farimah; Hasheminassab, Sina; Saffari, Arian; Schauer, James J; Delfino, Ralph J; Sioutas, Constantinos

    2016-01-15

    In this study, PM2.5 and PM0.18 (particles with dporganic carbons) and individual organic compounds. Concentrations of organic compounds were reported and compared with many previous studies in Central LA to quantify the impact of emissions control measurements that have been implemented for vehicular emissions over the past decades in this area. Moreover, a novel hybrid approach of molecular marker-based chemical mass balance (MM-CMB) analysis was conducted, in which a combination of source profiles that were previously obtained from a Positive Matrix Factorization (PMF) model in Central LA, were combined with some traditional source profiles. The model estimated the relative contributions from mobile sources (including gasoline, diesel, and smoking vehicles), wood smoke, primary biogenic sources (including emissions from vegetative detritus, food cooking, and re-suspended soil dust), and anthropogenic secondary organic carbon (SOC). Mobile sources contributed to 0.65 ± 0.25 μg/m(3) and 0.32 ± 0.25 μg/m(3) of PM2.5 OC in Central LA and Anaheim, respectively. Primary biogenic and anthropogenic SOC sources were major contributors to OC concentrations in both size fractions and sites. Un-apportioned OC ("other OC") accounted for an average 8.0 and 26% of PM2.5 OC concentration in Central LA and Anaheim, respectively. A comparison with previous studies in Central LA revealed considerable reduction of EC and OC, along with tracers of mobile sources (e.g. PAHs, hopanes and steranes) as a result of implemented regulations on vehicular emissions. Given the significant reduction of the impacts of mobile sources in the past decade in the LA Basin, the impact of SOC and primary biogenic emissions have a larger relative impact and the new hybrid model allows the impact of these sources to be better quantified.

  9. Fluorescently tuned nitrogen-doped carbon dots from carbon source with different content of carboxyl groups

    International Nuclear Information System (INIS)

    In this study, fluorescent nitrogen-doped carbon dots (NCDs) were tuned via varying the sources with different number of carboxyl groups. Owing to the interaction between amino and carboxyl, more amino groups conjugate the surface of the NCDs by the source with more carboxyl groups. Fluorescent NCDs were tuned via varying the sources with different content of carboxyl groups. Correspondingly, the nitrogen content, fluorescence quantum yields and lifetime of NCDs increases with the content of carboxyl groups from the source. Furthermore, cytotoxicity assay and cell imaging test indicate that the resultant NCDs possess low cytotoxicity and excellent biocompatibility

  10. Fluorescently tuned nitrogen-doped carbon dots from carbon source with different content of carboxyl groups

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hao; Wang, Yun; Dai, Xiao; Zou, Guifu, E-mail: kqzhang@suda.edu.cn, E-mail: zouguifu@suda.edu.cn [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Gao, Peng; Zhang, Ke-Qin, E-mail: kqzhang@suda.edu.cn, E-mail: zouguifu@suda.edu.cn; Du, Dezhuang [National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou 215123 (China); Guo, Jun [Testing and Analysis Center, Soochow University, Suzhou 215123 (China)

    2015-08-01

    In this study, fluorescent nitrogen-doped carbon dots (NCDs) were tuned via varying the sources with different number of carboxyl groups. Owing to the interaction between amino and carboxyl, more amino groups conjugate the surface of the NCDs by the source with more carboxyl groups. Fluorescent NCDs were tuned via varying the sources with different content of carboxyl groups. Correspondingly, the nitrogen content, fluorescence quantum yields and lifetime of NCDs increases with the content of carboxyl groups from the source. Furthermore, cytotoxicity assay and cell imaging test indicate that the resultant NCDs possess low cytotoxicity and excellent biocompatibility.

  11. Effect of carbon source on growth and lipid accumulation in Chlorella sorokiniana GXNN01

    Institute of Scientific and Technical Information of China (English)

    QIAO Hongjin; WANG Guangce

    2009-01-01

    Heterotrophic culture of microalgae to develop methods of increasing biomass productivity and storage lipids has brought new insight to commercial biodiesel production. To understand the relationship between heterotrophy and lipid production, the effects of carbon sources on the growth and lipid accumulation of Chlorella sorokiniana GXNN01 was studied. The alga exhibited an increased growth rate in response to the addition of carbon sources, which reached the stationary phase after 48 h at 30°C. In addition, glucose and NaAc had a significant effect on the lipid accumulation during the early-stationary phase. Specifically, the lipid content was 0.237±0.026 g g~(-1) cell dry weight and 0.272±0.041 g L~(-1) when glucose was used as the carbon source, whereas the lipid content reached 0.287±0.018 g g~(-1) cell dry weight and 0.288±0.008 g L~(-1) when NaAc was used as the carbon source. The neutral lipid content was found to first decrease and then increase over time during the growth phase. A glucose concentration of 20 mmol L~(-1) gave the maximal lipid yield and the optimum harvest time was the early-stationary phase.

  12. Comparative study on CO2 sources in soil developed on carbonate rock and non-carbonate rock in Central Guizhou

    Institute of Scientific and Technical Information of China (English)

    黎廷宇; 王世杰; 郑乐平

    2002-01-01

    In this paper, by using concentration and carbon stable isotope the.CO2 sources of soil profiles developed on limestone, dolostone and claystone basements in Central Guizhou, China are comparatively studied. The results show that CO2 concentration of soil profiles developed on different basements is different, having the following sequence: limestone>dolostone>claystone. Below the soil depth of 20 cm from the surface the δ13C value of CO2 in soil profile developed on limestone ranges from -12.811‰ - -13.492‰(PDB), that in soil profile developed on dolostone varys from -13.212‰--14.271‰(PDB) and that in soil profile developed on claystone is about -20.234‰- -21.485‰(PDB). Taking the carbon isotope of soil organic matter and carbonate rock as two isotopic endmembers, the proportion of soil C02 generated by dissolution of carbonate rock is calculated, about 21%-25% for soil profile developed on limestone basement, 19%-21% for soil profile developed on dolostone basement. There is almost no influx of

  13. Molasses as an efficient low-cost carbon source for biological Cr(VI) removal

    Energy Technology Data Exchange (ETDEWEB)

    Michailides, Michail K. [Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio (Greece); Tekerlekopoulou, Athanasia G., E-mail: atekerle@upatras.gr [Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio (Greece); Akratos, Christos S.; Coles, Sandra [Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio (Greece); Pavlou, Stavros [Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Stadiou Str., Platani, P.O. Box 1414, GR-26504 Patras (Greece); Department of Chemical Engineering, University of Patras, GR-26504 Patras (Greece); Vayenas, Dimitrios V. [Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio (Greece); Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Stadiou Str., Platani, P.O. Box 1414, GR-26504 Patras (Greece)

    2015-01-08

    Highlights: • Suspended and attached growth reactors were examined for Cr(VI) bio-reduction. • Molasses was proved an efficient and very low cost carbon source. • Molasses was more efficient than sugar in enhancing Cr(VI) reduction. • SBR with recirculation was the most proper operating mode. - Abstract: In the present study, indigenous microorganisms from industrial sludge were used to reduce the activity of Cr(VI). Molasses, a by-product of sugar processing, was selected as the carbon source (instead of sugar used in a previous work) as it is a low-cost energy source for bioprocesses. Initially, experiments were carried out in suspended growth batch reactors for Cr(VI) concentrations of 1.5–110 mg/L. The time required for complete Cr(VI) reduction increased with initial Cr(VI) concentration. Initial molasses concentration was also found to influence the Cr(VI) reduction rate. The optimal concentration for all initial Cr(VI) concentrations tested was 0.8 gC/L. Experiments were also carried out in packed-bed reactors. Three different operating modes were used to investigate the optimal performance and efficiency of the filter, i.e. batch, continuous and SBR with recirculation. The latter mode with a recirculation rate of 0.5 L/min lead to significantly high Cr(VI) reduction rates (up to 135 g/m{sup 2} d). The results of this work were compared with those of a similar work using sugar as the carbon source and indicate that molasses could prove a feasible technological solution to a serious environmental problem.

  14. Molasses as an efficient low-cost carbon source for biological Cr(VI) removal

    International Nuclear Information System (INIS)

    Highlights: • Suspended and attached growth reactors were examined for Cr(VI) bio-reduction. • Molasses was proved an efficient and very low cost carbon source. • Molasses was more efficient than sugar in enhancing Cr(VI) reduction. • SBR with recirculation was the most proper operating mode. - Abstract: In the present study, indigenous microorganisms from industrial sludge were used to reduce the activity of Cr(VI). Molasses, a by-product of sugar processing, was selected as the carbon source (instead of sugar used in a previous work) as it is a low-cost energy source for bioprocesses. Initially, experiments were carried out in suspended growth batch reactors for Cr(VI) concentrations of 1.5–110 mg/L. The time required for complete Cr(VI) reduction increased with initial Cr(VI) concentration. Initial molasses concentration was also found to influence the Cr(VI) reduction rate. The optimal concentration for all initial Cr(VI) concentrations tested was 0.8 gC/L. Experiments were also carried out in packed-bed reactors. Three different operating modes were used to investigate the optimal performance and efficiency of the filter, i.e. batch, continuous and SBR with recirculation. The latter mode with a recirculation rate of 0.5 L/min lead to significantly high Cr(VI) reduction rates (up to 135 g/m2 d). The results of this work were compared with those of a similar work using sugar as the carbon source and indicate that molasses could prove a feasible technological solution to a serious environmental problem

  15. Critical review of black carbon and elemental carbon source apportionment in Europe and the United States

    Science.gov (United States)

    Briggs, Nicole L.; Long, Christopher M.

    2016-11-01

    An increasing number of air pollution source apportionment studies in Europe and the United States have focused on the black carbon (BC) fraction of ambient particulate matter (PM) given its linkage with adverse public health and climate impacts. We conducted a critical review of European and US BC source apportionment studies published since 2003. Since elemental carbon (EC) has been used as a surrogate measure of BC, we also considered source apportionment studies of EC measurements. This review extends the knowledge presented in previous ambient PM source apportionment reviews because we focus on BC and EC and critically examine the differences between source apportionment results for different methods and source categories. We identified about 50 BC and EC source apportionment studies that have been conducted in either Europe or the US since 2003, finding a striking difference in the commonly used source apportionment methods between the two regions and variations in the assigned source categories. Using three dominant methodologies (radiocarbon, aethalometer, and macro-tracer methods) that only allow for BC to be broadly apportioned into either fossil fuel combustion or biomass burning source categories, European studies generally support fossil fuel combustion as the dominant ambient BC source, but also show significant biomass burning contributions, in particular in wintertime at non-urban locations. Among US studies where prevailing methods such as chemical mass balance (CMB) and positive matrix factorization (PMF) models have allowed for estimation of more refined source contributions, there are fewer findings showing the significance of biomass burning and variable findings on the relative proportion of BC attributed to diesel versus gasoline emissions. Overall, the available BC source apportionment studies provide useful information demonstrating the significance of both fossil fuel combustion and biomass burning BC emission sources in Europe and the US

  16. Estimating Terrestrial Wood Biomass from Observed Concentrations of Atmospheric Carbon Dioxide

    NARCIS (Netherlands)

    Schaefer, K. M.; Peters, W.; Carvalhais, N.; van der Werf, G.; Miller, J.

    2008-01-01

    We estimate terrestrial disequilibrium state and wood biomass from observed concentrations of atmospheric CO2 using the CarbonTracker system coupled to the SiBCASA biophysical model. Starting with a priori estimates of carbon flux from the land, ocean, and fossil fuels, CarbonTracker estimates net c

  17. High Frequency Measurements of Methane Concentrations and Carbon Isotopes at a Marsh and Landfill

    Science.gov (United States)

    Mortazavi, B.; Wilson, B.; Chanton, J.; Eller, K.; Dong, F.; Baer, D. S.; Gupta, M.; Dzwonkowski, B.

    2012-12-01

    High frequency measurements of methane concentrations and carbon isotopes can help constrain the source strengths of methane emitted to the atmosphere. We report here methane concentrations and 13C values measured at 0.5 Hz with cavity enhanced laser absorption spectrometers (Los Gatos Research) deployed at a saltmarsh in Alabama and a landfill in Florida. Methane concentrations and 13C at the saltmarsh were monitored over a 2.5 day time period at 2 m, 0.5 m above the ground as well as from the outflow of a flow-through (2 L) chamber placed on the Spartina alterniflora dominated marsh. A typical measurement cycle included regular samples from two tanks of known methane concentrations and isotopic values and from ambient air samples. Over the 2.5-day measurement period methane concentrations and isotopic ratios at 2 m averaged 1.85 ppm and -43.57‰ (±0.34, 1 SE), respectively. The concentration and isotopic values from the chamber outflow varied from 1.92 to 5.81 ppm and -38.5 to -59.3‰, respectively. Methane flux from the marsh ranged from undetectable to 3.6 mgC m-2hr-1, with high fluxes measured during low tide. The 13δCH4 of the emitted CH4 from the marsh, determined from a mass balance equation using the chamber inflow and outflow concentration and isotopic values ranged from -62.1 to -93.9‰ and averaged -77‰ (±1.25, 1SE). At the landfill ambient methane concentrations and 13C ratios measured over multiple days varied from 4.25 to 11.91 ppm and from -58.81 to -45.12‰, respectively. At higher methane concentrations the δ13C of CH4 was more depleted consistent with previously observed relationship at this site made by more traditional techniques. Over a 30-minute measurement period CH4 concentrations at the landfill could vary by as much as 15 ppm. The high frequency continuous optical measurements with field-deployed instruments provide us with an unprecedented temporal resolution of CH4 concentrations and isotopic ratios. These measurements will

  18. Carbon trading and carbon taxation: how to consider biotic sources and sinks

    International Nuclear Information System (INIS)

    The Kyoto Protocol (KP) to the UNFCCC includes land-use change and forestry in the carbon accounting process, limited to afforestation, reforestation and deforestation since 1990, and explicitly provides for the option of using a variety of flexibility mechanisms to meet the greenhouse gas (GHG) reduction targets stipulated in a more cost-efficient manner. Domestically, different countries might adopt different approaches to achieve their emission reduction objectives, such as carbon trading or carbon taxation, and it is not clear to date what the implications for bioenergy use, forestry, and land-use change can be expected to be. With respect to national GHG emissions trading, the main issues studied in this paper are: Should trading of fossil fuel emissions allowances be coupled with trading of biotic credits and debits? Should credits for carbon sequestration in forests be auctioned or grandfathered? Should there be a distinction between a carbon permit issued for an additional biotic sink and those issued for fossil fuel carbon emissions? Is there a difference for biotic carbon sinks and sources between one-time permits and permits that allow a continued release of GHG over some pre-specified time? Should permits be issued only for the carbon-stock changes that count under the KP? With respect to national carbon taxation schemes, two questions are investigated: Should a tax credit be given for afforestation/reforestation (and a tax debit for deforestation)? Should tax credits also be given for projects that sequester carbon but do not count under the KP (such as forest protection rather than forest management)? For both schemes a crucial point is that by the formulation chosen in the KP two different classes of forest are created (i.e. those counted and those not counted under the KP), so that the implications for land prices might be significant. From a conceptual point of view this paper addresses the above-mentioned questions and contrasts some of the major

  19. Role of metabolite transporters in source-sink carbon allocation.

    Science.gov (United States)

    Ludewig, Frank; Flügge, Ulf-Ingo

    2013-01-01

    Plants assimilate carbon dioxide during photosynthesis in chloroplasts. Assimilated carbon is subsequently allocated throughout the plant. Generally, two types of organs can be distinguished, mature green source leaves as net photoassimilate exporters, and net importers, the sinks, e.g., roots, flowers, small leaves, and storage organs like tubers. Within these organs, different tissue types developed according to their respective function, and cells of either tissue type are highly compartmentalized. Photoassimilates are allocated to distinct compartments of these tissues in all organs, requiring a set of metabolite transporters mediating this intercompartmental transfer. The general route of photoassimilates can be briefly described as follows. Upon fixation of carbon dioxide in chloroplasts of mesophyll cells, triose phosphates either enter the cytosol for mainly sucrose formation or remain in the stroma to form transiently stored starch which is degraded during the night and enters the cytosol as maltose or glucose to be further metabolized to sucrose. In both cases, sucrose enters the phloem for long distance transport or is transiently stored in the vacuole, or can be degraded to hexoses which also can be stored in the vacuole. In the majority of plant species, sucrose is actively loaded into the phloem via the apoplast. Following long distance transport, it is released into sink organs, where it enters cells as source of carbon and energy. In storage organs, sucrose can be stored, or carbon derived from sucrose can be stored as starch in plastids, or as oil in oil bodies, or - in combination with nitrogen - as protein in protein storage vacuoles and protein bodies. Here, we focus on transport proteins known for either of these steps, and discuss the implications for yield increase in plants upon genetic engineering of respective transporters. PMID:23847636

  20. Role of metabolite transporters in source-sink carbon allocation

    Directory of Open Access Journals (Sweden)

    Frank eLudewig

    2013-07-01

    Full Text Available Plants assimilate carbon dioxide during photosynthesis in chloroplasts. Assimilated carbon is subsequently allocated throughout the plant. Generally, two types of organs can be distinguished, mature green source leaves as net photoassimilate exporters, and net importers, the sinks, e.g. roots, flowers, small leaves and storage organs like tubers. Within these organs, different tissue types developed according to their respective function, and cells of either tissue type are highly compartmentalized. Photoassimilates are allocated to distinct compartments of these tissues in all organs, requiring a set of metabolite transporters mediating this intercompartmental transfer.The general route of photoassimilates can be briefly described as follows. Upon fixation of carbon dioxide in chloroplasts of mesophyll cells, triose phosphates either enter the cytosol for mainly sucrose formation or remain in the stroma to form transiently stored starch which is degraded during the night and enters the cytosol as maltose or glucose to be further metabolized to sucrose. In both cases, sucrose enters the phloem for long distance transport or is transiently stored in the vacuole, or can be degraded to hexoses which also can be stored in the vacuole.In the majority of plant species, sucrose is actively loaded into the phloem via the apoplast. Following long distance transport, it is released into sink organs, where it enters cells as source of carbon and energy. In storage organs, sucrose can be stored, or carbon derived from sucrose can be stored as starch in plastids, or as oil in oil bodies, or - in combination with nitrogen - as protein in protein storage vacuoles and protein bodies.Here, we focus on transport proteins known for either of these steps, and discuss the implications for yield increase in plants upon genetic engineering of respective transporters.

  1. Theoretical constraints on oxygen and carbon dioxide concentrations in the Precambrian atmosphere

    Science.gov (United States)

    Kasting, J. F.

    1987-01-01

    Simple (one-dimensional) climate models suggest that carbon dioxide concentrations during the Archean must have been at least 100-1000 times the present level to keep the Earth's surface temperature above freezing in the face of decreased solar luminosity. Such models provide only lower bounds on CO2, so it is possible that CO2 levels were substantially higher than this and that the Archean climate was much warmer than today. Periods of extensive glaciation during the early and late Proterozoic, on the other hand, indicate that the climate at these times was relatively cool. To be consistent with climate models CO2 partial pressures must have declined from approximately 0.03 to 0.3 bar around 2.5 Ga ago to between 10(-3) and 10(-2) bar at 0.8 Ga ago. This steep decrease in carbon dioxide concentrations may be inconsistent with paleosol data, which implies that pCO2 did not change appreciably during that time. Oxygen was essentially absent from the Earth's atmosphere and oceans prior to the emergence of a photosynthetic source, probably during the late Archean. During the early Proterozoic the atmosphere and surface ocean were apparently oxidizing, while the deep ocean remained reducing. An upper limit of 6 x 10(-3) bar for pO2 at this time can be derived by balancing the burial rate of organic carbon with the rate of oxidation of ferrous iron in the deep ocean. The establishment of oxidizing conditions in the deep ocean, marked by the disappearance of banded iron formations approximately 1.7 Ga ago, permitted atmospheric oxygen to climb to its present level. O2 concentrations may have remained substantially lower than today, however, until well into the Phanerozoic.

  2. Air Pollution in China: Mapping of Concentrations and Sources

    OpenAIRE

    Rohde, Robert A.; Muller, Richard A.

    2015-01-01

    China has recently made available hourly air pollution data from over 1500 sites, including airborne particulate matter (PM), SO2, NO2, and O3. We apply Kriging interpolation to four months of data to derive pollution maps for eastern China. Consistent with prior findings, the greatest pollution occurs in the east, but significant levels are widespread across northern and central China and are not limited to major cities or geologic basins. Sources of pollution are widespread, but are particu...

  3. A Carbon Nanotube Electron Source Based Ionization Vacuum Gauge

    Energy Technology Data Exchange (ETDEWEB)

    Changkun Dong; Ganapati Myneni

    2003-10-01

    The results of fabrication and performance of an ionization vacuum gauge using a carbon nanotube (CNT) electron source are presented. The electron source was constructed with multi-wall nanotubes (MWNT), which were grown using thermal chemical vapor deposition (CVD) process. The electron emission of the source was stable in vacuum pressure up to 10-7 Torr, which is better than the metal field emitters. The measurement linearity of the gauge was better than {+-}10% from 10-6 to 10-10 Torr. The gauge sensitivity of 4 Torr-1 was achieved under 50 {micro}A electron emission in nitrogen. The gauge is expected to find applications in vacuum measurements from 10-7 Torr to below 10-11 Torr.

  4. Optical Performance of Carbon-Nanotube Electron Sources

    Science.gov (United States)

    de Jonge, Niels; Allioux, Myriam; Oostveen, Jim T.; Teo, Kenneth B.; Milne, William I.

    2005-05-01

    The figure of merit for the electron optical performance of carbon-nanotube (CNT) electron sources is presented. This figure is given by the relation between the reduced brightness and the energy spread in the region of stable emission. It is shown experimentally that a CNT electron source exhibits a highly stable emission process that follows the Fowler-Nordheim theory for field emission, fixing the relationship among the energy spread, the current, and the radius. The performance of the CNT emitter under realistic operating conditions is compared with state-of-the-art electron point sources. It is demonstrated that the reduced brightness is a function of the tunneling parameter, a measure of the energy spread at low temperatures, only, independent of the geometry of the emitter.

  5. Exposition by inhalation to the formaldehyde in the air. Source, measures and concentrations; Exposition par inhalation au formaldehyde dans l'air. Source, mesures et concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I

    2004-12-15

    This document presents the main techniques today available to characterize the formaldehyde concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  6. Utilization of carbon sources in a northern Brazilian mangrove ecosystem

    Science.gov (United States)

    Giarrizzo, Tommaso; Schwamborn, Ralf; Saint-Paul, Ulrich

    2011-12-01

    Carbon and nitrogen stable isotope ratios ( 13C and 15N) and trophic level (TL) estimates based on stomach content analysis and published data were used to assess the contribution of autotrophic sources to 55 consumers in an intertidal mangrove creek of the Curuçá estuary, northern Brazil. Primary producers showed δ 13C signatures ranging between -29.2 and -19.5‰ and δ 15N from 3.0 to 6.3‰. The wide range of the isotopic composition of carbon of consumers (-28.6 to -17.1‰) indicated that different autotrophic sources are important in the intertidal mangrove food webs. Food web segregation structures the ecosystem into three relatively distinct food webs: (i) mangrove food web, where vascular plants contribute directly or indirectly via POM to the most 13C-depleted consumers (e.g. Ucides cordatus and zooplanktivorous food chains); (ii) algal food web, where benthic algae are eaten directly by consumers (e.g. Uca maracoani, mullets, polychaetes, several fishes); (iii) mixed food web where the consumers use the carbon from different primary sources (mainly benthivorous fishes). An IsoError mixing model was used to determine the contributions of primary sources to consumers, based on δ 13C values. Model outputs were very sensitive to the magnitude of trophic isotope fractionation and to the variability in 13C data. Nevertheless, the simplification of the system by a priori aggregation of primary producers allowed interpretable results for several taxa, revealing the segregation into different food webs.

  7. Achieving high performance in intermediate temperature direct carbon fuel cells with renewable carbon as a fuel source

    International Nuclear Information System (INIS)

    Highlights: • Bamboo fiber and waste paper were pyrolyzed to generate bamboo carbon and waste paper carbon as anode fuels of IT-DCFC. • Superior cell performance was achieved with the waste paper carbon. • The results suggested the high performance was due to the highest thermal reactivity and the catalytic inherent impurities. • Calcite and kaolinite as inherent impurities favored the thermal decomposition and the electrooxidation of carbon. - Abstract: Three kinds of carbon sources obtained from carbon black, bamboo fiber and waste paper were investigated as anode fuels in an intermediate temperature direct carbon fuel cell. The carbon sources were characterized with X-ray photoelectron spectroscopy, thermal gravimetric analysis, etc. The results indicated that the waste paper carbon was more abundant in calcite and kaolinite, and showed higher thermal reactivity in the intermediate temperature range compared with the other two carbon sources. The cell performance was tested at 650 °C in a hybrid single cell, using Sm0.20Ce0.80O2−x as the electrolyte. As a result, the cell fed with waste paper carbon showed the highest performance among the three carbon sources, with a peak power density of 225 mW cm−2. The results indicated that its inherent impurities, such as calcite and kaolinite, might favor the thermal gasification of renewable carbon sources, which resulted in the enhanced performance of the intermediate temperature direct carbon fuel cell

  8. Ligninolytic Activity of Ganoderma strains on Different Carbon Sources

    Directory of Open Access Journals (Sweden)

    TYPUK ARTININGSIH

    2006-10-01

    Full Text Available Lignin is a phenylpropanoid polymers with only few carbon bonds might be hydrolized. Due to its complexity, lignin is particularly difficult to decompose. Ganoderma is one of white rot fungi capable of lignin degradation. The ligninolytic of several species Ganoderma growing under different carbon sources was studied under controlled conditions which P. chrysosporium was used as standard comparison.Three types of ligninolytic, namely LiP, MnP, and laccase were assessed quantitatively and qualitatively. Ratio between clear zone and diameter of fungal colony was used for measuring specific activity qualitatively.Four sspecies of Ganoderma showed positive ligninolytic qualitatively that G. lucidum KT2-32 gave the highest ligninolytic. Activity of LiP and MnP in different carbon sources was consistently resulted by G. lucidum KT2-32, while the highest activity of laccase was shown by G. ochrolaccatum SA2-14. Medium of Indulin AT affected production of protein extracellular and induced ligninolytic. Glucose, BMC, and pine sawdust did not affect the activity of ligninolytic. The specific activity of Ganoderma species was found to be higher than the one of P. chrysosporium.

  9. New study on the correlation between carbon dioxide concentration in the environment and radon monitor devices.

    Science.gov (United States)

    Shahrokhi, A; Burghele, B D; Fábián, F; Kovács, T

    2015-12-01

    The influence of high geogenic carbon dioxide concentrations on monitoring devices might present a significant challenge to the measurement of radon concentrations in environments with a high level of carbon dioxide concentration such as volcano sites, mofettes, caves, etc. In this study, the influence of carbon dioxide concentration on several different types of radon monitor devices - including Alpha Spectrometry (Sarad RTM 2200, EQF 3220, RAD7), Ionizing Chamber (AlphaGUARD PQ2000 PRO) and Active Cell (Active scintillation cell, Pylon 300A) - was examined to represent new aspects of radon measuring in environments with carbon dioxide. In light of the results, all measuring devices were exposed to variable conditions affected by carbon dioxide concentration, except for the AlphaGUARD, which was kept in a steady state throughout the experiment. It was observed that alpha spectroscopy devices were affected by carbon dioxide, since measured radon concentrations decreased in the presence of 70% and 90% carbon dioxide concentrations by 26.5 ± 2% and 14.5 ± 2.5% for EQF 3220, and 32 ± 2% and 35.5 ± 2% for RTM 2200. However, the ionizing chamber instrument was unaffected by changes in carbon dioxide concentration. It was determined that the RAD7 performed relatively inefficiently in the presence of carbon dioxide concentrations higher than 67% by an overall efficiency factor of approximately 0.52, confirming that it is not an admissible radon monitor instrument in environments with high carbon dioxide concentrations. PMID:26281966

  10. New study on the correlation between carbon dioxide concentration in the environment and radon monitor devices.

    Science.gov (United States)

    Shahrokhi, A; Burghele, B D; Fábián, F; Kovács, T

    2015-12-01

    The influence of high geogenic carbon dioxide concentrations on monitoring devices might present a significant challenge to the measurement of radon concentrations in environments with a high level of carbon dioxide concentration such as volcano sites, mofettes, caves, etc. In this study, the influence of carbon dioxide concentration on several different types of radon monitor devices - including Alpha Spectrometry (Sarad RTM 2200, EQF 3220, RAD7), Ionizing Chamber (AlphaGUARD PQ2000 PRO) and Active Cell (Active scintillation cell, Pylon 300A) - was examined to represent new aspects of radon measuring in environments with carbon dioxide. In light of the results, all measuring devices were exposed to variable conditions affected by carbon dioxide concentration, except for the AlphaGUARD, which was kept in a steady state throughout the experiment. It was observed that alpha spectroscopy devices were affected by carbon dioxide, since measured radon concentrations decreased in the presence of 70% and 90% carbon dioxide concentrations by 26.5 ± 2% and 14.5 ± 2.5% for EQF 3220, and 32 ± 2% and 35.5 ± 2% for RTM 2200. However, the ionizing chamber instrument was unaffected by changes in carbon dioxide concentration. It was determined that the RAD7 performed relatively inefficiently in the presence of carbon dioxide concentrations higher than 67% by an overall efficiency factor of approximately 0.52, confirming that it is not an admissible radon monitor instrument in environments with high carbon dioxide concentrations.

  11. Culture strategies for lipid production using acetic acid as sole carbon source by Rhodosporidium toruloides.

    Science.gov (United States)

    Huang, Xiang-Feng; Liu, Jia-Nan; Lu, Li-Jun; Peng, Kai-Ming; Yang, Gao-Xiang; Liu, Jia

    2016-04-01

    Rhodosporidium toruloides AS 2.1389 was tested using different concentrations of acetic acid as a low-cost carbon source for the production of microbial lipids, which are good raw materials for biodiesel production. It grew and had higher lipid contents in media containing 4-20 g/L acetic acid as the sole carbon source, compared with that in glucose-containing media under the same culture conditions. At acetic acid concentrations as high as 20 g/L and the optimal carbon-to-nitrogen ratio (C/N) of 200 in a batch culture, the highest biomass production was 4.35 g/L, with a lipid content of 48.2%. At acetic acid concentrations as low as 4 g/L, a sequencing batch culture (SBC) with a C/N of 100 increased biomass production to 4.21 g/L, with a lipid content of 38.6%. These results provide usable culture strategies for lipid production by R. toruloides AS 2.1389 when using diverse waste-derived volatile fatty acids.

  12. Geochemistry of dissolved inorganic carbon in a Coastal Plain aquifer. 2. Modeling carbon sources, sinks, and δ13C evolution

    Science.gov (United States)

    McMahon, Peter B.; Chapelle, Francis H.

    1991-01-01

    Stable isotope data for dissolved inorganic carbon (DIC), carbonate shell material and cements, and microbial CO2 were combined with organic and inorganic chemical data from aquifer and confining-bed pore waters to construct geochemical reaction models along a flowpath in the Black Creek aquifer of South Carolina. Carbon-isotope fractionation between DIC and precipitating cements was treated as a Rayleigh distillation process. Organic matter oxidation was coupled to microbial fermentation and sulfate reduction. All reaction models reproduced the observed chemical and isotopic compositions of final waters. However, model 1, in which all sources of carbon and electron-acceptors were assumed to be internal to the aquifer, was invalidated owing to the large ratio of fermentation CO2 to respiration CO2 predicted by the model (5–49) compared with measured ratios (two or less). In model 2, this ratio was reduced by assuming that confining beds adjacent to the aquifer act as sources of dissolved organic carbon and sulfate. This assumption was based on measured high concentrations of dissolved organic acids and sulfate in confining-bed pore waters (60–100 μM and 100–380 μM, respectively) relative to aquifer pore waters (from less than 30 μM and 2–80 μM, respectively). Sodium was chosen as the companion ion to organic-acid and sulfate transport from confining beds because it is the predominant cation in confining-bed pore waters. As a result, excessive amounts of Na-for-Ca ion exchange and calcite precipitation (three to four times more cement than observed in the aquifer) were required by model 2 to achieve mass and isotope balance of final water. For this reason, model 2 was invalidated. Agreement between model-predicted and measured amounts of carbonate cement and ratios of fermentation CO2 to respiration CO2 were obtained in a reaction model that assumed confining beds act as sources of DIC, as well as organic acids and sulfate. This assumption was

  13. Russia's black carbon emissions: focus on diesel sources

    Science.gov (United States)

    Kholod, Nazar; Evans, Meredydd; Kuklinski, Teresa

    2016-09-01

    Black carbon (BC) is a significant climate forcer with a particularly pronounced forcing effect in polar regions such as the Russian Arctic. Diesel combustion is a major global source of BC emissions, accounting for 25-30 % of all BC emissions. While the demand for diesel is growing in Russia, the country's diesel emissions are poorly understood. This paper presents a detailed inventory of Russian BC emissions from diesel sources. Drawing on a complete Russian vehicle registry with detailed information about vehicle types and emission standards, this paper analyzes BC emissions from diesel on-road vehicles. We use the COPERT emission model (COmputer Programme to calculate Emissions from Road Transport) with Russia-specific emission factors for all types of on-road vehicles. On-road diesel vehicles emitted 21 Gg of BC in 2014: heavy-duty trucks account for 60 % of the on-road BC emissions, while cars represent only 5 % (light commercial vehicles and buses account for the remainder). Using Russian activity data and fuel-based emission factors, the paper also presents BC emissions from diesel locomotives and ships, off-road engines in industry, construction and agriculture, and generators. The study also factors in the role of superemitters in BC emissions from diesel on-road vehicles and off-road sources. The total emissions from diesel sources in Russia are estimated to be 49 Gg of BC and 17 Gg of organic carbon (OC) in 2014. Off-road diesel sources emitted 58 % of all diesel BC in Russia.

  14. Carbonaceous aerosols on the south edge of the Tibetan Plateau: concentrations, seasonality and sources

    Directory of Open Access Journals (Sweden)

    Z. Cong

    2014-10-01

    Full Text Available To quantitatively evaluate the effect of carbonaceous aerosols on the south edge of the Tibetan Plateau, aerosol samples were collected weekly from August 2009 to July 2010 at Mt. Everest (Qomolangma Station for Atmospheric and Environmental Observation and Research, briefly QOMS, 28.36° N, 86.95° E, 4276 m a.s.l.. The samples were analyzed for organic carbon (OC, elemental carbon (EC, water-soluble organic carbon (WSOC and major ions. The average concentrations of OC, EC and WSOC were 1.43, 0.25 and 0.77 μg m−3, respectively. The concentration levels of OC and EC at QOMS are comparable to those at high elevation sites on the southern slopes of the Himalayas (Langtang and NCO-P, but three to six times lower than those at Manora Peak, India and Godavari, Nepal. Sulfate was the most abundant anion species followed by nitrate, accounting for 25 and 12% of total ionic mass, respectively. Ca2+ was the most abundant cation species (annual average of 0.88 μg m−3. The various aerosol compositions showed distinctive seasonality. The dust loading, represented by Ca2+ concentration, was relatively constant throughout the year. While OC, EC and other ionic species (NH4+, K+, NO3−, and SO42− exhibited a pronounced peak in the pre-monsoon period and a minimum in the monsoon season. Similar seasonal trends of aerosol composition were also reported previously from the southern slope of the Himalayas, such as Langtang and NCO-P. This phenomenon indicates that both slopes of Himalayas share a common atmospheric environment regime. The strong correlation of OC and EC in QOMS aerosols with K+ and levoglucosan indicates that they were mainly originated from biomass burning. The active fire spots observed by MODIS and their backward trajectories further demonstrate that in pre-monsoon season, agricultural and forest fires in the northern India and Nepal were most likely sources of carbonaceous aerosol at QOMS. In addition to large-scale atmospheric

  15. Carbonaceous aerosols on the south edge of the Tibetan Plateau: concentrations, seasonality and sources

    Science.gov (United States)

    Cong, Z.; Kang, S.; Kawamura, K.; Liu, B.; Wan, X.; Wang, Z.; Gao, S.; Fu, P.

    2015-02-01

    To quantitatively evaluate the effect of carbonaceous aerosols on the south edge of the Tibetan Plateau, aerosol samples were collected weekly from August 2009 to July 2010 at Qomolangma (Mt. Everest) Station for Atmospheric and Environmental Observation and Research (QOMS, 28.36° N, 86.95° E, 4276 m a.s.l.). The average concentrations of organic carbon (OC), elemental carbon (EC) and water-soluble organic carbon were 1.43, 0.25 and 0.77 μg m-3, respectively. The concentration levels of OC and EC at QOMS are comparable to those at high-elevation sites on the southern slopes of the Himalayas (Langtang and Nepal Climate Observatory at Pyramid, or NCO-P), but 3 to 6 times lower than those at Manora Peak, India, and Godavari, Nepal. Sulfate was the most abundant anion species followed by nitrate, accounting for 25 and 12% of total ionic mass, respectively. Ca2+ was the most abundant cation species (annual average of 0.88 μg m-3). The dust loading, represented by Ca2+ concentration, was relatively constant throughout the year. OC, EC and other ionic species (NH4+, K+, NO3- and SO42-) exhibited a pronounced peak in the pre-monsoon period and a minimum in the monsoon season, being similar to the seasonal trends of aerosol composition reported previously from the southern slope of the Himalayas, such as Langtang and NCO-P. The strong correlation of OC and EC in QOMS aerosols with K+ and levoglucosan indicates that they mainly originated from biomass burning. The fire spots observed by MODIS and backward air-mass trajectories further demonstrate that in pre-monsoon season, agricultural and forest fires in northern India and Nepal were most likely sources of carbonaceous aerosol at QOMS. Moreover, the CALIOP observations confirmed that air-pollution plumes crossed the Himalayas during this period. The highly coherent variation of daily aerosol optical depth (500 nm) between QOMS and NCO-P indicates that both slopes of the Himalayas share a common atmospheric environment

  16. Kupier prize lecture: Sources of solar-system carbon

    Science.gov (United States)

    Anders, Edward; Zinner, Ernst

    1994-01-01

    We have tried to deconvolve Solar-System carbon into its sources, on the basis of C-12/C-13 ratios (equivalent to R). Interstellar SiC in meteorites, representing greater than 4.6-Ga-old stardust from carbon stars, is isotopically heavier (bar R = 38 +/- 2) than Solar-System carbon (89), implying that the latter contains an additional, light component. A likely source are massive stars, mainly Type II supernovae and Wolf-Rayet stars, which, being O-rich, eject their C largely as CO rather than carbonaceous dust. The fraction of such light C in the Solar System depends on R(sub light) in the source. For R(sub light) = 180-1025 (as in 'Group 4' meteoritic graphite spherules, which apparently came from massive stars greater than 4.6 Ga ago), the fraction of light C is 0.79-0.61. Similar results are obtained for present-day data on red giants and interstellar gas. Although both have become enriched in C-13 due to galactic evolution (to bar-R = 20 and 57), the fraction of the light component in interstellar gas again is near 0.7. (Here bar R represents the mean of a mixture calculated via atom fractions; it is not identical to the arithmetic mean R). Interstellar graphite, unlike SiC, shows a large peak at R approximately equal 90, near the solar value. Although some of the grains may be of local origin, others show anomalies in other elements and hence are exotic. Microdiamonds, with R = 93, also are exotic on the basis of their Xe and N. Apparently R approximately 90 was a fairly common composition 4.6 Ga ago, of stars as well as the ISM.

  17. Quantification of carbon sources for isoprene emission in poplar leaves

    Science.gov (United States)

    Kreutzwieseer, J.; Graus, M.; Schnitzler, J. P.; Heizmann, U.; Rennenberg, H.; Hansel, A.

    2003-12-01

    Isoprene is the most abundant volatile organic compound emitted by plants and in particular by trees. Current interest in understanding its biosynthesis in chloroplasts is forced by the important role isoprene plays in atmospheric chemistry. Leaf isoprene formation is closely linked to photosynthesis by a dynamic use of recently fixed photosynthetic precursors in the chloroplast. Under steady state conditions in [13C]CO2 atmosphere approximately 75 % of isoprene became labeled within minutes. The source of unlabeled C is suggested to be of extra-chloroplastidic and/or from starch degradation. In order to test whether these alternative carbon sources - leaf internal C-pools and xylem-transported carbohydrates, contribute to leaf isoprene formation in poplar (Populus tremula x P. alba) on-line proton-transfer-reaction-mass spectrometry (PTR-MS) was used to follow 13C-labeling kinetics.

  18. Regional prediction of carbon isotopes in soil carbonates for Asian dust source tracer

    Science.gov (United States)

    Chen, Bing; Cui, Xinjuan; Wang, Yaqiang

    2016-10-01

    Dust particles emitted from deserts and semi-arid lands in northern China cause particulate pollution that increases the burden of disease particularly for urban population in East Asia. The stable carbon isotopes (δ13C) of carbonates in soils and dust aerosols in northern China were investigated. We found that the δ13C of carbonates in surface soils in northern China showed clearly the negative correlation (R2 = 0.73) with Normalized Difference Vegetation Index (NDVI). Using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite-derived NDVI, we predicted the regional distribution of δ13C of soil carbonates in deserts, sandy lands, and steppe areas. The predictions show the mean δ13C of -0.4 ± 0.7‰ in soil carbonates in Taklimakan Desert and Gobi Deserts, and the isotope values decrease to -3.3 ± 1.1‰ in sandy lands. The increase in vegetation coverage depletes 13C in soil carbonates, thus the steppe areas are predicted by the lowest δ13C levels (-8.1 ± 1.7‰). The measurements of atmospheric dust samples at eight sites showed that the Asian dust sources were well assigned by the 13C mapping in surface soils. Predicting 13C in large geographical areas with fine resolution offers a cost-effective tracer to monitor dust emissions from sandy lands and steppe areas which show an increasing role in Asian dust loading driven by climate change and human activities.

  19. Growth and xanthan production of Xanthomonas campestris depending on the N-source concentration

    Energy Technology Data Exchange (ETDEWEB)

    Prell, A. [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology; Lasik, J. [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology; Konicek, J. [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology; Sobotka, M. [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology; Sys, J. [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology

    1995-11-01

    Growth of X. campestris and production of xanthan were studied in several batch fermentations with different starting concentrations of N-source. The dependencies of growth, productivity and yields on initial N-source concentration were observed. The maximum yields in the course of cultivations were identified. (orig.)

  20. Rapid biological oxidation of methanol in the tropical Atlantic: significance as a microbial carbon source

    Directory of Open Access Journals (Sweden)

    J. L. Dixon

    2011-09-01

    Full Text Available Methanol is the second most abundant organic gas in the atmosphere after methane, and is ubiquitous in the troposphere. It plays a significant role in atmospheric oxidant chemistry and is biogeochemically active. Large uncertainties exist about whether the oceans are a source or sink of methanol to the atmosphere. Even less is understood about what reactions in seawater determine its concentration, and hence flux across the sea surface interface. We report here concentrations of methanol between 151–296 nM in parts of the oligotrophic North Atlantic, with corresponding microbial uptake rates between 2–146 nM d−1, suggesting turnover times as low as 1 day (1–25 days in surface waters of the oligotrophic tropical North East Atlantic. Methanol is mainly (≥97% used by microbes for obtaining energy in oligotrophic regions, which contrasts with shelf and coastal areas where between 20–50% can be used for cell growth. Comparisons of microbial methanol oxidation rates with parallel determinations of bacterial leucine uptake suggest that methanol contributes on average 13% to bacterial carbon demand in the central northern Atlantic gyre (maximum of 54%. In addition, the contribution that methanol makes to bacterial carbon demand varies as a power function of chlorophyll a concentrations; suggesting for concentrations <0.2 μg l−1 that methanol can make a significant contribution to bacterial carbon demand. However, our low air to sea methanol flux estimates of 7.2–13 μmol m−2 d−1 suggest that the atmosphere is not a major methanol source. We conclude that there must be a major, as yet unidentified, in situ oceanic methanol source in these latitudes which we suggest is sunlight driven decomposition of organic matter.

  1. Sources, transformations, and hydrological processes that control stream nitrate and dissolved organic matter concentrations during snowmelt in an upland forest

    Science.gov (United States)

    Sebestyen, S.D.; Boyer, E.W.; Shanley, J.B.; Kendall, C.; Doctor, D.H.; Aiken, G.R.; Ohte, N.

    2008-01-01

    We explored catchment processes that control stream nutrient concentrations at an upland forest in northeastern Vermont, USA, where inputs of nitrogen via atmospheric deposition are among the highest in the nation and affect ecosystem functioning. We traced sources of water, nitrate, and dissolved organic matter (DOM) using stream water samples collected at high frequency during spring snowmelt. Hydrochemistry, isotopic tracers, and end-member mixing analyses suggested the timing, sources, and source areas from which water and nutrients entered the stream. Although stream-dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) both originated from leaching of soluble organic matter, flushing responses between these two DOM components varied because of dynamic shifts of hydrological flow paths and sources that supply the highest concentrations of DOC and DON. High concentrations of stream water nitrate originated from atmospheric sources as well as nitrified sources from catchment soils. We detected nitrification in surficial soils during late snowmelt which affected the nitrate supply that was available to be transported to streams. However, isotopic tracers showed that the majority of nitrate in upslope surficial soil waters after the onset of snowmelt originated from atmospheric sources. A fraction of the atmospheric nitrogen was directly delivered to the stream, and this finding highlights the importance of quick flow pathways during snowmelt events. These findings indicate that interactions among sources, transformations, and hydrologic transport processes must be deciphered to understand why concentrations vary over time and over space as well as to elucidate the direct effects of human activities on nutrient dynamics in upland forest streams. Copyright 2008 by the American Geophysical Union.

  2. Comprehensive analysis of the metabolome of Pseudomonas putida S12 grown on different carbon sources.

    Science.gov (United States)

    van der Werf, Mariët J; Overkamp, Karin M; Muilwijk, Bas; Koek, Maud M; van der Werff-van der Vat, Bianca J C; Jellema, Renger H; Coulier, Leon; Hankemeier, Thomas

    2008-04-01

    Metabolomics is an emerging, powerful, functional genomics technology that involves the comparative non-targeted analysis of the complete set of metabolites in an organism. We have set-up a robust quantitative metabolomics platform that allows the analysis of 'snapshot' metabolomes. In this study, we have applied this platform for the comprehensive analysis of the metabolite composition of Pseudomonas putida S12 grown on four different carbon sources, i.e. fructose, glucose, gluconate and succinate. This paper focuses on the microbial aspects of analyzing comprehensive metabolomes, and demonstrates that metabolomes can be analyzed reliably. The technical (i.e. sample work-up and analytical) reproducibility was on average 10%, while the biological reproducibility was approximately 40%. Moreover, the energy charge values of the microbial samples generated were determined, and indicated that no biotic or abiotic changes had occurred during sample work-up and analysis. In general, the metabolites present and their concentrations were very similar after growth on the different carbon sources. However, specific metabolites showed large differences in concentration, especially the intermediates involved in the degradation of the carbon sources studied. Principal component discriminant analysis was applied to identify metabolites that are specific for, i.e. not necessarily the metabolites that show those largest differences in concentration, cells grown on either of these four carbon sources. For selected enzymatic reactions, i.e. the glucose-6-phosphate isomerase, triosephosphate isomerase and phosphoglyceromutase reactions, the apparent equilibrium constants (K(app)) were calculated. In several instances a carbon source-dependent deviation between the apparent equilibrium constant (K(app)) and the thermodynamic equilibrium constant (K(eq)) was observed, hinting towards a potential point of metabolic regulation or towards bottlenecks in biosynthesis routes. For glucose-6

  3. Carbon Monoxide Emission and Concentration Models for Chiang Mai Urban Area

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    An emission inventory containing emissions from traffic and other sources was complied. Based on the analysis, Carbon Monoxide (CO) emissions from traffic play a very important role in CO levels in Chiang Mai area. Analysis showed that CO emissions from traffic during rush hours contributed approximately 90% of total CO emissions. Regional Atmospheric Modeling System (RAMS) was applied to simulate wind fields and temperatures in the Chiang Mai area, and eight cases were selected to study annual variations in wind fields and temperatures. Model results can reflect major features of wind fields and diurnal variations in temperatures. For evaluating the model performance, model results were compared with observed wind speed, wind direction and temperature, which were monitored at a meteorological tower. Comparison showed that model results are in good agreement with observations, and the model captured many of the observed features. HYbrid Particle And Concentration Transport model (HYPACT) was used to simulate CO concentration in the Chiang Mai area. Model results generally agree well with observed CO concentrations at the air quality monitoring stations, and can explain observed CO diurnal variations.

  4. Effects of carbon sources, oxygenation and ethanol on the production of inulinase by Kluyveromyces marxianus YX01

    Directory of Open Access Journals (Sweden)

    JIAOQI GAO

    2012-01-01

    Full Text Available Inulinase is one of the most important factors in consolidated bioprocessing, which combines enzyme production, inulin saccharification, and ethanol fermentation into a single process. In our study, inulinase production and cell growth of Kluyveromyces marxianus YX01 under different conditions were studied. Carbon source was shown to be significant on the production of inulinase, because the activity of inulinase was higher using inulin as a carbon source compared with glucose or fructose. The concentration of the carbon source had a repressive effect on the activity of inulinase. When the concentration was increased to 60 g/L, inulinase activity was only 50% compared with carbon source concentration of 20 g/L. Enzyme activity was also strongly influenced by aeration rate. It has been shown that the activity of inulinase and cell growth under anaerobic conditions were maintained at low levels, but aeration at 1.0 vvm (air volume/broth volume minute led to higher activity. Inulinase activity per unit biomass was not significantly different under different aeration rates. Ethanol had a repressive effect on the cell growth. Cells ceased growing when the level of ethanol was greater than 9% (v/v, but ethanol did not affect the activity of secreted inulinase and the enzyme was stable at ethanol concentration up to 15%.

  5. High-resolution carbon dioxide concentration record 650,000-800,000 years before present

    DEFF Research Database (Denmark)

    Lüthi, Dieter; Le Floch, Martine; Bereiter, Bernhard;

    2008-01-01

    Changes in past atmospheric carbon dioxide concentrations can be determined by measuring the composition of air trapped in ice cores from Antarctica. So far, the Antarctic Vostok and EPICA Dome C ice cores have provided a composite record of atmospheric carbon dioxide levels over the past 650......,000 years. Here we present results of the lowest 200 m of the Dome C ice core, extending the record of atmospheric carbon dioxide concentration by two complete glacial cycles to 800,000 yr before present. From previously published data and the present work, we find that atmospheric carbon dioxide...... is strongly correlated with Antarctic temperature throughout eight glacial cycles but with significantly lower concentrations between 650,000 and 750,000 yr before present. Carbon dioxide levels are below 180 parts per million by volume (p.p.m.v.) for a period of 3,000 yr during Marine Isotope Stage 16...

  6. Carbon dioxide as a carbon source in organic transformation: carbon-carbon bond forming reactions by transition-metal catalysts.

    OpenAIRE

    Tsuji, Yasushi; Fujihara, Tetsuaki

    2012-01-01

    Recent carbon-carbon bond forming reactions of carbon dioxide with alkenes, alkynes, dienes, aryl zinc compounds, aryl boronic esters, aryl halides, and arenes having acidic C-H bonds are reviewed in which transition-metal catalysts play an important role.

  7. Comparison of manufactured and black carbon nanoparticle concentrations in aquatic sediments

    NARCIS (Netherlands)

    Koelmans, A.A.; Nowack, B.; Wiesner, M.

    2009-01-01

    In this paper, we show that concentrations of manufactured carbon-based nanoparticles (MCNPs) in aquatic sediments will be negligible compared to levels of black carbon nanoparticles (BCNPs). This is concluded from model calculations accounting for MCNP sedimentation fluxes, removal rates due to agg

  8. Thermal hydrolysis of sludge and the use of hydrolysate as carbon source for denitrification

    Energy Technology Data Exchange (ETDEWEB)

    Barlindhaug, J.

    1995-10-01

    As a consequence of the North Sea- and the Baltic Sea Treaties as well as the Wastewater Directive of the EU, several large wastewater treatment plants discharging to sensitive receiving waters have to include phosphorus as well as nitrogen removal. This thesis evaluates the so called NTH-process for nutrient removal. In this process pre-precipitation is used in front of a biological nitrogen removal step that is based on a combination of pre- and post-denitrification in moving bed biofilm reactors. The biological step is followed by a final separation step, possibly after coagulant addition. Carbon source for the post denitrification step is made available by hydrolysis of the sludge produced. The idea is that the particulate organic matter, which in a traditional pre-denitrification step would have to be enzymatically hydrolyzed, can be more efficiently hydrolyzed in a concentrated sidestream and used in a post-denitrification step. In the thesis hydrolyzed sludge is used as a carbon source for denitrification. The objective is to investigate the influence of varying hydrolysis conditions on the composition and amount of the thermal hydrolysate produced, as well as the quality of the hydrolysate as a carbon source for denitrification. 201 refs., 78 refs., 53 tabs.

  9. [Effects of carbon and nitrogen sources on 5-keto-gluconic acid production].

    Science.gov (United States)

    Tan, Zhilei; Wang, Hongcui; Wei, Yuqiao; Li, Yanyan; Zhong, Cheng; Jia, Shiru

    2014-01-01

    Gluconobacter oxydans is known to oxidize glucose to gluconic acid (GA), and subsequently, to 2-keto-gluconic acid (2KGA) and 5-keto-gluconic acid (5KGA), while 5KGA can be converted to L-(+)-tartaric acid. In order to increase the production of 5KGA, Gluconobacter oxydans HGI-1 that converts GA to 5KGA exclusively was chosen in this study, and effects of carbon sources (lactose, maltose, sucrose, amylum and glucose) and nitrogen sources (yeast extract, fish meal, corn steep liquor, soybean meal and cotton-seed meal) on 5KGA production were investigated. Results of experiment in 500 mL shake-flask show that the highest yield of 5KGA (98.20 g/L) was obtained using 100 g/L glucose as carbon source. 5KGA reached 100.20 g/L, 109.10 g/L, 99.83 g/L with yeast extract, fish meal and corn steep liquor as nitrogen source respectively, among which the optimal nitrogen source was fish meal. The yield of 5KGA by corn steep liquor is slightly lower than that by yeast extract. For the economic reason, corn steep liquor was selected as nitrogen source and scaled up to 5 L stirred-tank fermentor, and the final concentration of 5KGA reached 93.80 g/L, with its maximum volumetric productivity of 3.48 g/(L x h) and average volumetric productivity of 1.56 g/(L x h). The result obtained in this study showed that carbon and nitrogen sourses for large-scale production of 5KGA by Gluconobacter oxydans HGI-1 were glucose and corn steep liquor, respectively, and the available glucose almost completely (85.93%) into 5KGA.

  10. Direct measurement of surface carbon concentrations for lunar soil breccias

    Science.gov (United States)

    Filleux, C.; Spear, R. H.; Tombrello, T. A.; Burnett, D. S.

    1978-01-01

    A nuclear reaction depth profiling technique previously described by Filleux et al. (1977) has been used to measure the depth distribution of C on grain surfaces for Apollo 11, 15, 16 and 17 soil breccias. The surface C concentration of all samples studied lies between 2 and 8 times 10 to the 15th atoms per sq cm, showing no correlation with the volume C, which varies over an order of magnitude. If the observed variation represents the presence of unexposed grains on the surfaces studied, these results indicate a steady state surface C concentration of 5 to 10 times 10 to the 15th atoms per sq cm, accumulated over a time scale short compared with that required for the formation of volume-related C and with the mean lifetime of grains at the lunar surface. About one-third to one-half of the total C in lunar soil seems to be surface-correlated.

  11. Fossil and Nonfossil Sources of Organic and Elemental Carbon Aerosols in the Outflow from Northeast China.

    Science.gov (United States)

    Zhang, Yan-Lin; Kawamura, Kimitaka; Agrios, Konstantinos; Lee, Meehye; Salazar, Gary; Szidat, Sönke

    2016-06-21

    Source quantification of carbonaceous aerosols in the Chinese outflow regions still remains uncertain despite their high mass concentrations. Here, we unambiguously quantified fossil and nonfossil contributions to elemental carbon (EC) and organic carbon (OC) of total suspended particles (TSP) from a regional receptor site in the outflow of Northeast China using radiocarbon measurement. OC and EC concentrations were lower in summer, representing mainly marine air, than in other seasons, when air masses mostly traveled over continental regions in Mongolia and northeast China. The annual-mean contribution from fossil-fuel combustion to EC was 76 ± 11% (0.1-1.3 μg m(-3)). The remaining 24 ± 11% (0.03-0.42 μg m(-3)) was attributed to biomass burning, with slightly higher contribution in the cold period (∼31%) compared to the warm period (∼21%) because of enhanced emissions from regional biomass combustion sources in China. OC was generally dominated by nonfossil sources, with an annual average of 66 ± 11% (0.5-2.8 μg m(-3)), approximately half of which was apportioned to primary biomass-burning sources (34 ± 6%). In winter, OC almost equally originated from primary OC (POC) emissions and secondary OC (SOC) formation from fossil fuel and biomass-burning sources. In contrast, summertime OC was dominated by primary biogenic emissions as well as secondary production from biogenic and biomass-burning sources, but fossil-derived SOC was the smallest contributor. Distinction of POC and SOC was performed using primary POC-to-EC emission ratios separated for fossil and nonfossil emissions. PMID:27203471

  12. Electrospun Fibres of Polyhydroxybutyrate Synthesized by Ralstonia eutropha from Different Carbon Sources

    Directory of Open Access Journals (Sweden)

    Victor U. Irorere

    2014-01-01

    Full Text Available The properties of PHB may be affected by the carbon source used in its production and this may affect nanofibres made from this polymer by electrospinning. In this study, P(3-HB was produced from glucose, rapeseed oil, and olive oil by Ralstonia eutropha H16. Cell growth and polymer production were higher in olive or rapeseed oil supplemented media compared to glucose supplemented media. FT-IR, 1H-, 13C-NMR, and ESI/MSn confirmed that the synthesized polymers were P(3-HB. SEM micrograph showed the formation of nanofibres from P(3-HB samples with the fibre diameters dependent on the source of the carbon used in polymer synthesis and the concentration of the polymer in the electrospinning solution. GPC showed that P(3-HB from glucose (G-PHB had a higher molecular weight (7.35×105 gmol−1 compared to P(3-HB from rapeseed (R-PHB and olive (O-PHB oil. Differential scanning calorimetry (DSC showed that the crystallinity of the electrospun polymers reduces with decreasing polymer concentration with R-PHB having lower crystallinity at all concentrations used. These observation shows that more PHB yield can be obtained using either rapeseed or olive oil compared to glucose with glucose producing polymers of higher molecular weight. It also show that electrospinning could be used to reduce the crystallinity of PHB fibres.

  13. Nitrification and denitrification in biological activated carbon filter for treating high ammonia source water

    Institute of Scientific and Technical Information of China (English)

    Jianguang LIU; Xiaojian ZHANG; Zhansheng WANG

    2008-01-01

    Since the ammonia in the effluent of the tradi-tional water purification process could not meet the supply demand, the advanced treatment of a high concentration of NH4+-N micro-polluted source water by biological activated carbon filter (BACF) was tested. The filter was operated in the downflow manner and the results showed that the remov-ing rate of NH4+-N was related to the influent concentration of NH4+-N. Its removing rate could be higher than 95% when influent concentration was under 1.0 mg/L. It could also decrease with the increasing influent concentration when the NH4+-N concentration was in the range from 1.5-to 4.9 mg/L and the dissolved oxygen (DO) in the infuent was under 10 mg/L, and the minimum removing rate could be 30%. The key factor of restricting nitrifcation in BACF was the influent DO. When the influent NH4+-N concentration was high, the DO in water was almost depleted entirely by the nitrifying and hetetrophic bacteria in the depth of 0.4 m filter and the filter layer was divided into aerobic and anoxic zones. The nitrification and degradation of organic matters existed in the aerobic zone, while the denitrification occurred in the anoxic zone. Due to the limited carbon source, the denitrification could not be carried out properly, which led to the accu-mulation of the denitrification intermediates such as NO2-. In addition to the denitrification bacteria, the nitrification and the heterotrophic bacteria existed in the anoxic zone.

  14. Acetic Acid bacteria: physiology and carbon sources oxidation.

    Science.gov (United States)

    Mamlouk, Dhouha; Gullo, Maria

    2013-12-01

    Acetic acid bacteria (AAB) are obligately aerobic bacteria within the family Acetobacteraceae, widespread in sugary, acidic and alcoholic niches. They are known for their ability to partially oxidise a variety of carbohydrates and to release the corresponding metabolites (aldehydes, ketones and organic acids) into the media. Since a long time they are used to perform specific oxidation reactions through processes called "oxidative fermentations", especially in vinegar production. In the last decades physiology of AAB have been widely studied because of their role in food production, where they act as beneficial or spoiling organisms, and in biotechnological industry, where their oxidation machinery is exploited to produce a number of compounds such as l-ascorbic acid, dihydroxyacetone, gluconic acid and cellulose. The present review aims to provide an overview of AAB physiology focusing carbon sources oxidation and main products of their metabolism.

  15. Parametric uncertainties in global model simulations of black carbon column mass concentration

    Science.gov (United States)

    Pearce, Hana; Lee, Lindsay; Reddington, Carly; Carslaw, Ken; Mann, Graham

    2016-04-01

    Previous studies have deduced that the annual mean direct radiative forcing from black carbon (BC) aerosol may regionally be up to 5 W m‑2 larger than expected due to underestimation of global atmospheric BC absorption in models. We have identified the magnitude and important sources of parametric uncertainty in simulations of BC column mass concentration from a global aerosol microphysics model (GLOMAP-Mode). A variance-based uncertainty analysis of 28 parameters has been performed, based on statistical emulators trained on model output from GLOMAP-Mode. This is the largest number of uncertain model parameters to be considered in a BC uncertainty analysis to date and covers primary aerosol emissions, microphysical processes and structural parameters related to the aerosol size distribution. We will present several recommendations for further research to improve the fidelity of simulated BC. In brief, we find that the standard deviation around the simulated mean annual BC column mass concentration varies globally between 2.5 x 10‑9 g cm‑2 in remote marine regions and 1.25 x 10‑6 g cm‑2 near emission sources due to parameter uncertainty Between 60 and 90% of the variance over source regions is due to uncertainty associated with primary BC emission fluxes, including biomass burning, fossil fuel and biofuel emissions. While the contributions to BC column uncertainty from microphysical processes, for example those related to dry and wet deposition, are increased over remote regions, we find that emissions still make an important contribution in these areas. It is likely, however, that the importance of structural model error, i.e. differences between models, is greater than parametric uncertainty. We have extended our analysis to emulate vertical BC profiles at several locations in the mid-Pacific Ocean and identify the parameters contributing to uncertainty in the vertical distribution of black carbon at these locations. We will present preliminary

  16. Black carbon concentration and deposition estimations in Finland by the regional aerosol–climate model REMO-HAM

    Directory of Open Access Journals (Sweden)

    A. I. Hienola

    2013-04-01

    Full Text Available The prediction skill of the regional aerosol–climate model REMO-HAM was assessed against the black carbon (BC concentration measurements from five locations in Finland, with focus on Hyytiälä station for the year 2005. We examined to what extent the model is able to reproduce the measurements using several statistical tools: median comparison, overlap coefficient (OVL; the common area under two probability distributions curves and Z score (a measure of standard deviation, shape and spread of the distributions. The results of the statistics showed that the model is biased low. The local and regional emissions of BC have a significant contribution, and the model tendency to flatten the observed BC is most likely dominated by the lack of domestic burning of biofuel in the emission inventories. A further examination of the precipitation data from both measurements and model showed that there is no correlation between REMO's excessive precipitation and BC underestimation. This suggests that the excessive wet removal is not the main cause of the low black carbon concentration output. In addition, a comparison of wind directions in relation with high black carbon concentrations shows that REMO-HAM is able to predict the BC source directions relatively well. Cumulative black carbon deposition fluxes over Finland were estimated, including the deposition on snow.

  17. Carbon Nanotube/Magnesium Composite as a Hydrogen Source.

    Science.gov (United States)

    Yu, Min Kyu; Se, Kwon Oh; Kim, Min Joong; Hwang, Jae Won; Yoon, Byoung Young; Kwon, Hyuk Sang

    2015-11-01

    Hydrogen produced using the steam reforming process contains sulfur and carbon monoxide that are harmful to the Pt catalyst in proton-exchange-membrane fuel cells (PEMFCs). However, CO-free hydrogen can be generated from the hydrolysis of either Al in strongly alkaline water or Mg in neutral water with chlorides such as sea water. The hydrogen generation rate from the hydrolysis of Mg is extremely slow and linearly proportional to the corrosion rate of Mg in chloride water. In this work, we fabricated a carbon nanotube (CNT)--reinforced Mg--matrix composite by Spark Plasma Sintering as a fast hydrogen generation source for a PEMFC. The CNTs distributed in the Mg matrix act as numerous local cathodes, and hence cause severe galvanic corrosion between the Mg-matrix anode and CNT-cathode in NaCl solution. It was found that the hydrogen generation rate from the hydrolysis of the 5 vol.% CNT/Mg composite is 3300 times faster than that of the Mg without CNTs due primarily to the galvanic corrosion effect.

  18. Land use effects on terrestrial carbon sources and sinks

    Institute of Scientific and Technical Information of China (English)

    Josep; G.; Canadell

    2002-01-01

    Current and past land use practices are critical in determining the distribution and size of global terrestrial carbon (C) sources and sinks. Althoughfossil fuel emissions dominate the anthropogenic perturbation of the global C cycle, land use still drives the largest portion of anthropogenic emissions in a number of tropical regions of Asia. The size of the emission flux owing to land use change is still the biggest uncertainty in the global C budget. The Intergovernmental Panel on Climate Change (IPCC) reported a flux term of 1.7 PgC@a-1 for 1990-1995 but more recent estimates suggest the magnitude of this source may be only of 0.96 PgC@a-1 for the 1990s. In addition, current and past land use practices are now thought to contribute to a large degree to the northern hemisphere terrestrial sink, and are the dominant driver for some regional sinks. However, mechanisms other than land use change need to be invoked in order to explain the inferred C sink in the tropics. Potential candidates are the carbon dioxide (CO2) fertilization and climate change; fertilization due to nitrogen (N) deposition is believed to be small or nil. Although the potential for managing C sinks is limited, improved land use management and new land uses such as reforestation and biomass fuel cropping, can further enhance current terrestrial C sinks. Best management practices in agriculture alone could sequester 0.4-0.8 PgC per year in soils if implemented globally. New methodologies to ensure verification and permanency of C sequestration need to be developed.

  19. Assessment of the Impact of Climate Change and Land Management Change on Soil Organic Carbon Content, Leached Carbon Rates and Dissolved Organic Carbon Concentrations

    NARCIS (Netherlands)

    Stergiadi, Maria; de Nijs, Ton; van der Perk, Marcel; Bonten, Luc

    2014-01-01

    Climate change is projected to significantly affect the concentrations and mobility of contaminants, such as metals and pathogens, in soil, groundwater and surface water. Climate- and land management-induced changes in soil organic carbon and dissolved organic carbon levels may promote the transport

  20. Indoor carbon monoxide and PM{sub 2.5} concentrations by cooking fuels in Pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqui, A.R. (Aga Khan Univ., Dept. Community Health Sciences, Karachi (Pakistan)); Lee, K. (Seoul National Univ., Graduate School of Public Health (Korea)); Bennett, D.; Yang, X.; Gold, E.B. (Univ. California at Davis, Dept. of Public Health, CA (United States)); Brown, K.H. (Univ. California at Davis, Program in Int. Nutrition, CA (United States)); Bhutta, Z.A. (Aga Khan Univ., Dep. of Pediatrics, Karachi (Pakistan))

    2009-02-15

    In developing countries biomass combustion is a frequently used source of domestic energy and may cause indoor air pollution. Carbon monoxide (CO) and particulate matter with an aerodynamic diameter of 2.5 mum or less (PM{sub 2.5}) were measured in kitchens using wood or natural gas (NG) in a semi-rural community in Pakistan. Daytime CO and PM{sub 2.5} levels were measured for eight continuous hours in 51 wood and 44 NG users from December 2005 to April 2006. The laser photometer PM{sub 2.5} (Dustrak, TSI) was calibrated for field conditions and PM{sub 2.5} measurements were reduced by a factor of 2.77. CO was measured by an electrochemical monitor (Model T15v, Langan). The arithmetic mean for daytime CO concentration was 29.4 ppm in wood users; significantly higher than 7.5 ppm in NG users (P < 0.001). The arithmetic mean for daytime PM{sub 2.5} concentrations was 2.74 mg/m3 in wood users; significantly higher than 0.38 mg/m3 in NG users (P < 0.001). Higher peak levels of CO and PM{sub 2.5} were also observed in wood users. Time spent in the kitchen during fuel burning was significantly related to increasing CO and PM{sub 2.5} concentrations in wood users. These findings suggest that cooking with wood fuel may lead to hazardous concentrations of CO and PM{sub 2.5}. (au)

  1. Oxygen vectors used for S-adenosylmethionine production in recombinant Pichia pastoris with sorbitol as supplemental carbon source.

    Science.gov (United States)

    Zhang, Jian-Guo; Wang, Xue-Dong; Zhang, Ji-Ning; Wei, Dong-Zhi

    2008-04-01

    In order to increase the yield of S-adenosylmethionine (SAM) in recombinant Pichia pastoris, a strategy of adding oxygen vectors and supplemental carbon sources was described. Three organic solutions were used as oxygen vectors for SAM accumulation at different concentrations and addition times. Firstly, n-hexane (0.5%) or n-heptane (1.0%) was added after 72 h of cultivation to improve SAM production. Carbon metabolism was scarce during the induction phase because of low methanol concentration. Secondly, sorbitol (1.2%), selected from three candidates (glycerol, lactic acid, and sorbitol), was used as the supplemental carbon source. The yield of SAM was improved significantly (53.26%) at 1.0%n-heptane added at 72 h (48 h induction), 1.2% sorbitol added at 72, 96, and 120 h of cultivation and 1.0% methanol added every 24 h during cultivation.

  2. Application of biogenic carbon dioxide produced by yeast with different carbon sources for attraction of mosquitoes towards adult mosquito traps.

    Science.gov (United States)

    Sukumaran, D; Ponmariappan, S; Sharma, Atul K; Jha, Hemendra K; Wasu, Yogesh H; Sharma, Ajay K

    2016-04-01

    Surveillance is a prime requisite for controlling arthropod vectors like mosquitoes that transmit diseases such as malaria, dengue and chikungunya. Carbon dioxide (CO2) is one of the main cues from vertebrate breath that attracts mosquitoes towards the host. Hence, CO2 is used as an attractant during surveillance of mosquitoes either from commercial cylinders or dry ice for mosquito traps. In the present study, the biogenic carbon dioxide production was optimized with different carbon sources such as glucose, simple sugar and jaggery with and without yeast peptone dextrose (YPD) media using commercial baker's yeast. The results showed that yeast produced more biogenic CO2 with simple sugar as compared to other carbon sources. Further substrate concentration was optimized for the continuous production of biogenic CO2 for a minimum of 12 h by using 10 g of baker's yeast with 50 g of simple sugar added to 1.5 l distilled water (without YPD media) in a 2-l plastic bottle. This setup was applied in field condition along with two different mosquito traps namely Mosquito Killing System (MKS) and Biogents Sentinel (BGS) trap. Biogenic CO2 from this setup has increased the trapping efficiency of MKS by 6.48-fold for Culex quinquefasciatus, 2.62-fold for Aedes albopictus and 1.5-fold for Anopheles stephensi. In the case of BGS, the efficiency was found to be increased by 3.54-fold for Ae. albopictus, 4.33-fold for An. stephensi and 1.3-fold for Armigeres subalbatus mosquitoes. On the whole, plastic bottle setup releasing biogenic CO2 from sugar and yeast has increased the efficiency of MKS traps by 6.38-fold and 2.74-fold for BGS traps as compared to traps without biogenic CO2. The present study reveals that, among different carbon sources used, simple sugar as a substance (which is economical and readily available across the world) yielded maximum biogenic CO2 with yeast. This setup can be used as an alternative to CO2 cylinder and dry ice in any adult mosquito traps to

  3. Dynamics of Intracellular Polymers in Enhanced Biological Phosphorus Removal Processes under Different Organic Carbon Concentrations

    Directory of Open Access Journals (Sweden)

    Lizhen Xing

    2013-01-01

    Full Text Available Enhanced biological phosphorus removal (EBPR may deteriorate or fail during low organic carbon loading periods. Polyphosphate accumulating organisms (PAOs in EBPR were acclimated under both high and low organic carbon conditions, and then dynamics of polymers in typical cycles, anaerobic conditions with excess organic carbons, and endogenous respiration conditions were examined. After long-term acclimation, it was found that organic loading rates did not affect the yield of PAOs and the applied low organic carbon concentrations were advantageous for the enrichment of PAOs. A low influent organic carbon concentration induced a high production of extracellular carbohydrate. During both anaerobic and aerobic endogenous respirations, when glycogen decreased to around 80 ± 10 mg C per gram of volatile suspended solids, PAOs began to utilize polyphosphate significantly. Regressed by the first-order reaction model, glycogen possessed the highest degradation rate and then was followed by polyphosphate, while biomass decay had the lowest degradation rate.

  4. Synthesis of Carbon Nanotubes of Few Walls Using Aliphatic Alcohols as a Carbon Source

    Directory of Open Access Journals (Sweden)

    Francisco Espinosa-Magaña

    2013-06-01

    Full Text Available Carbon nanotubes with single and few walls are highly appreciated for their technological applications, regardless of the limited availability due to their high production cost. In this paper we present an alternative process that can lead to lowering the manufacturing cost of CNTs of only few walls by means of the use of the spray pyrolysis technique. For this purpose, ferrocene is utilized as a catalyst and aliphatic alcohols (methanol, ethanol, propanol or butanol as the carbon source. The characterization of CNTs was performed by scanning electron microscopy (SEM and transmission electron microscopy (TEM. The study of the synthesized carbon nanotubes (CNTs show important differences in the number of layers that constitute the nanotubes, the diameter length, the quantity and the quality as a function of the number of carbons employed in the alcohol. The main interest of this study is to give the basis of an efficient synthesis process to produce CNTs of few walls for applications where small diameter is required.

  5. Atmospheric carbon dioxide concentration across the mid-Pleistocene transition.

    Science.gov (United States)

    Hönisch, Bärbel; Hemming, N Gary; Archer, David; Siddall, Mark; McManus, Jerry F

    2009-06-19

    The dominant period of Pleistocene glacial cycles changed during the mid-Pleistocene from 40,000 years to 100,000 years, for as yet unknown reasons. Here we present a 2.1-million-year record of sea surface partial pressure of CO2 (Pco2), based on boron isotopes in planktic foraminifer shells, which suggests that the atmospheric partial pressure of CO2 (pco2) was relatively stable before the mid-Pleistocene climate transition. Glacial Pco2 was approximately 31 microatmospheres higher before the transition (more than 1 million years ago), but interglacial Pco2 was similar to that of late Pleistocene interglacial cycles (CO2 concentration and global climate, but the lack of a gradual decrease in interglacial Pco2 does not support the suggestion that a long-term drawdown of atmospheric CO2 was the main cause of the climate transition.

  6. Crescimento de Acidovorax avenae subsp. citrulli sob diferentes temperaturas, pH, concentrações de cloreto de sódio e fontes de carbono Growth of Acidovorax avenae subsp. citrulli under different variable temperature, pH, sodium chloride concentrations and carbon sources

    Directory of Open Access Journals (Sweden)

    Márcia Tanajura Cavalcanti

    2005-12-01

    growth was 7.4 with minimum and maximum of 4 and 10.8, respectively e; Aac growth was reduced with the elevation of NaCl concentration and, 6.2% was lethal. All tested carbohydrates were utilized by Aac strains as carbon source. However small growth variations were observed by the speed and intensity of substrate utilization with acid production.

  7. How low can you go? Assessing minimum concentrations of NSC in carbon limited tree saplings

    Science.gov (United States)

    Hoch, Guenter; Hartmann, Henrik; Schwendener, Andrea

    2016-04-01

    Tissue concentrations of non-structural carbohydrates (NSC) are frequently used to determine the carbon balance of plants. Over the last years, an increasing number of studies have inferred carbon starvation in trees under environmental stress like drought from low tissue NSC concentrations. However, such inferences are limited by the fact that minimum concentrations of NSC required for survival are not known. So far, it was hypothesized that even under lethal carbon starvation, starch and low molecular sugar concentrations cannot be completely depleted and that minimum NSC concentrations at death vary across tissues and species. Here we present results of an experiment that aimed to determine minimum NSC concentrations in different tissues of saplings of two broad-leaved tree species (Acer pseudoplatanus and Quercus petratea) exposed to lethal carbon starvation via continuous darkening. In addition, we investigated recovery rates of NSC concentrations in saplings that had been darkened for different periods of time and were then re-exposed to light. Both species survived continuous darkening for about 12 weeks (confirmed by testing the ability to re-sprout after darkness). In all investigated tissues, starch concentrations declined close to zero within three to six weeks of darkness. Low molecular sugars also decreased strongly within the first weeks of darkness, but seemed to stabilize at low concentrations of 0.5 to 2 % dry matter (depending on tissue and species) almost until death. NSC concentrations recovered surprisingly fast in saplings that were re-exposed to light. After 3 weeks of continuous darkness, tissue NSC concentrations recovered within 6 weeks to levels of unshaded control saplings in all tissues and in both species. To our knowledge, this study represents the first experimental attempt to quantify minimum tissue NSC concentrations at lethal carbon starvation. Most importantly, our results suggest that carbon-starved tree saplings are able to

  8. Comparative study on bacterial carbon sources in lake sediments : the role of methanotrophy

    OpenAIRE

    Steger, Kristin; K. Premke; Gudasz, Cristian; Boschker, H.T.S.; Tranvik, Lars J.

    2015-01-01

    Methane-derived carbon can be important in both benthic and pelagic food webs. Either generated in the anaerobic layers of the sediment or in the anaerobic hypolimnion of stratified eutrophic lakes, methane is an excellent carbon source for aerobic methanotrophic bacteria. The very negative methane delta C-13-signal in the methanotrophic biomass provides an excellent opportunity to trace the use of methane-derived carbon in food webs. We studied carbon sources of benthic bacteria in a range o...

  9. Towards a Carbon Nanotube Ionization Source for Planetary Atmosphere Exploration

    Science.gov (United States)

    Oza, A. V.; Leblanc, F.; Berthelier, J. J.; Becker, J.; Coulomb, R.; Gilbert, P.; Hong, N. T.; Lee, S.; Vettier, L.

    2015-12-01

    The characterization of planetary exospheres today, relies on the development of a highly efficient ionization source, due to the scant neutral molecules (n atmospheres provide insight on to physical processes known to occur such as: space weathering, magneto-atmosphere interactions, as well as atmospheric escape mechanisms, all of which are being heavily investigated via current 3D Monte Carlo simulations (Turc et al. 2014, Leblanc et al. 2016 in prep) at LATMOS. Validation of these studies will rely on in-situ observations in the coming decades. Neutral detection strongly depends on electron-impact ionization which via conventional cathode-sources, such as thermal filaments (heated up to 2000 K), may only produce the target ionization essential for energy-measurements with large power consumption. Carbon nanotubes (CNTs) however are ideal low-power, cold cathodes, when subject to moderate electric fields (E ~ 1 MV / m). We present our current device, a small CNT chip, of emission area 15 mm2, emitting electrons that pass through an anode grid and subsequent electrostatic analyzer. The device currently extracts hundreds of µAmperes with applied external voltages ~ -150 Volts, approaching minimum power consumption plasma sputtering the icy regolith with heavy ions and electrons (keV < E < MeV), producing predominately molecular oxygen (Johnson et al. 2002).

  10. Use of Plackett-Burman design for rapid screening of nitrogen and carbon sources for the production of lipase in solid state fermentation by Yarrowia lipolytica from mustard oil cake (Brassica napus)

    OpenAIRE

    Sarat Babu Imandi; Sita Kumari Karanam; Hanumantha Rao Garapati

    2014-01-01

    Mustard oil cake (Brassica napus), the residue obtained after extraction of mustard oil from mustard oil seeds, was investigated for the production of lipase under solid state fermentation (SSF) using the marine yeast Yarrowia lipolytica NCIM 3589. Process parameters such as incubation time, biomass concentration, initial moisture content, carbon source concentration and nitrogen source concentration of the medium were optimized. Screening of ten nitrogen and five carbon sources has been acco...

  11. Selective carboxylate production by controlling hydrogen, carbon dioxide and substrate concentrations in mixed culture fermentation

    NARCIS (Netherlands)

    Arslan, D.; Steinbusch, K.J.J.; Diels, L.; Wever, de H.; Hamelers, H.V.M.; Buisman, C.J.N.

    2013-01-01

    This research demonstrated the selective production of n-butyrate from mixed culture by applying 2 bar carbon dioxide into the headspace of batch fermenters or by increasing the initial substrate concentration. The effect of increasing initial substrate concentration was investigated at 8, 13.5 and

  12. Carbon Isotope Ratios Of Carbon Dioxide In The Urban Salt Lake Valley, Utah USA: Source And Long-Term Monitoring Observations

    Science.gov (United States)

    Ehleringer, J.; Lai, C.; Strong, C.; Pataki, D. E.; Bowling, D. R.; Schauer, A. J.; Bush, S.

    2011-12-01

    A high-precision, decadal record of carbon isotope ratios in atmospheric carbon dioxide has been produced for the urbanized Salt Lake Valley, Utah USA. These data complement a similar time series of atmospheric carbon dioxide concentrations for different locations in the same urban region. This isotopic record includes diurnal and nocturnal observations based on flask (IRMS-based) and continuous (TDL-based) measurement systems. These data reveal repeatable diurnal and seasonal variations in the anthropogenic and biogenic carbon sources that can be used to reconstruct different source inputs. As the Salt Lake Valley is an isolated urban region, the impacts of local anthropogenic inputs can be distinguished from regional patterns as measured by NOAA at the rural Wendover monitoring station 200 km to the west of the Salt Lake Valley. Complementary data, such as vehicle exhaust, emission from power plants and household furnaces, plant and soil organic matter, are also provided to quantify the carbon isotope ratios of the predominant anthropogenic and biogenic sources within the Salt Lake Valley. The combined source and long-term observational values will be made freely available and their utility is discussed for modeling efforts including urban metabolism modeling and atmospheric trace gas modeling.

  13. The effect of atmospheric CO2 concentration on carbon isotope fractionation in C3 land plants

    Science.gov (United States)

    Schubert, Brian A.; Jahren, A. Hope

    2012-11-01

    Because atmospheric carbon dioxide is the ultimate source of all land-plant carbon, workers have suggested that pCO2 level may exert control over the amount of 13C incorporated into plant tissues. However, experiments growing plants under elevated pCO2 in both chamber and field settings, as well as meta-analyses of ecological and agricultural data, have yielded a wide range of estimates for the effect of pCO2 on the net isotopic discrimination (Δδ13Cp) between plant tissue (δ13Cp) and atmospheric CO2 (δ13CCO2). Because plant stomata respond sensitively to plant water status and simultaneously alter the concentration of pCO2 inside the plant (ci) relative to outside the plant (ca), any experiment that lacks environmental control over water availability across treatments could result in additional isotopic variation sufficient to mask or cancel the direct influence of pCO2 on Δδ13Cp. We present new data from plant growth chambers featuring enhanced dynamic stabilization of moisture availability and relative humidity, in addition to providing constant light, nutrient, δ13CCO2, and pCO2 level for up to four weeks of plant growth. Within these chambers, we grew a total of 191 C3 plants (128 Raphanus sativus plants and 63 Arabidopsis thaliana) across fifteen levels of pCO2 ranging from 370 to 4200 ppm. Three types of plant tissue were harvested and analyzed for carbon isotope value: above-ground tissues, below-ground tissues, and leaf-extracted nC31-alkanes. We observed strong hyperbolic correlations (R ⩾ 0.94) between the pCO2 level and Δδ13Cp for each type of plant tissue analyzed; furthermore the linear relationships previously suggested by experiments across small (10-350 ppm) changes in pCO2 (e.g., 300-310 ppm or 350-700 ppm) closely agree with the amount of fractionation per ppm increase in pCO2 calculated from our hyperbolic relationship. In this way, our work is consistent with, and provides a unifying relationship for, previous work on carbon isotopes

  14. Reduction of the environmental concentration of air pollutants by proper geometrical orientation of industrial line sources

    International Nuclear Information System (INIS)

    An account is given of an Israeli study of two line sources, one composed of 10 and the other of 20 individual sources. The height of release ranged from 15.7 to 39.6 m, with a uniform rate of release of a gaseous pollutant of 1 Ci/s for each source. Average pollutant concentration was plotted as a function of the rotation angle of the line sources. Reduction of pollutant concentration by a particular rotation of the line sources attained values of up to 50%. At certain rotation angles of the line sources, the environmental concentration was lower even as compared with a single high source. Results also depended on atmospheric conditions. It is suggested that considering the increase in cost of augmenting the height of release as a means of reducing the air pollutant concentration, determination of the optimum geometric orientation of the line sources should be considered as an economical means of improving environmental air quality. (U.K.)

  15. Quantification and radiocarbon source apportionment of black carbon in atmospheric aerosols using the CTO-375 method

    Science.gov (United States)

    Zencak, Zdenek; Elmquist, Marie; Gustafsson, Örjan

    To make progress towards linking the atmosphere and biogeosphere parts of the black carbon (BC) cycle, a chemothermal oxidation method (CTO-375), commonly applied for isolating BC from complex geomatrices such as soils, sediments and aquatic particles, was applied to investigate the BC also in atmospheric particles. Concentrations and 14C-based source apportionment of CTO-375 based BC was established for a reference aerosol (NIST RM-8785) and for wintertime aerosols collected in Stockholm and in a Swedish background area. The results were compared with thermal-optical (OC/EC) measurements. For NIST RM-8785, a good agreement was found between the BC CTO-375 concentration and the reported elemental carbon (EC) concentration measured by the "Speciation Trends Network—National Institute of Occupational Safety and Health" method (EC NIOSH) with BC CTO-375 of 0.054±0.002 g g -1 and EC NIOSH of 0.067±0.008 g g -1. In contrast, there was an average factor of ca. 20 difference between BC CTO-375 and EC NIOSH for the ambient Scandinavian wintertime aerosols, presumably reflecting a combination of BC CTO-375 isolating only the recalcitrant soot-BC portion of the BC continuum and the EC NIOSH metric inadvertently including some intrinsically non-pyrogenic organic matter. Isolation of BC CTO-375 with subsequent off-line radiocarbon analysis yielded fraction modern values (fM) for total organic carbon (TOC) of 0.93 (aerosols from a Swedish background area), and 0.58 (aerosols collected in Stockholm); whereas the fM for BC CTO-375 isolates were 1.08 (aerosols from a Swedish background area), and 0.87 (aerosols collected in Stockholm). This radiocarbon-based source apportionment suggests that contribution from biomass combustion to cold-season atmospheric BC CTO-375 in Stockholm was 70% and in the background area 88%.

  16. Elevated atmospheric carbon dioxide concentration: effects of increased carbon input in a Lolium perenne soil on microorganisms and decomposition

    NARCIS (Netherlands)

    Ginkel, van J.H.; Gorissen, A.; Polci, D.

    2000-01-01

    Effects of ambient and elevated atmospheric CO2 concentrations (350 and 700 μl l-1) on net carbon input into soil, the production of root-derived material and the subsequent microbial transformation were investigated. Perennial ryegrass plants (L. perenne L.) were labelled in a continuously labelled

  17. Concentrations and characteristics of organic carbon in surface water in Arizona: Influence of urbanization

    Science.gov (United States)

    Westerhoff, P.; Anning, D.

    2000-01-01

    Dissolved (DOC) and total (TOC) organic carbon concentrations and compositions were studied for several river systems in Arizona, USA. DOC composition was characterized by ultraviolet and visible absorption and fluorescence emission (excitation wavelength of 370 nm) spectra characteristics. Ephemeral sites had the highest DOC concentrations, and unregulated perennial sites had lower concentrations than unregulated intermittent sites, regulated sites, and sites downstream from wastewater-treatment plants (p wastewater-treatment plant effluent were higher in DOC concentration (p wastewater-treatment plants) was found to affect temporal variability in DOC concentration and composition. (C) 2000 Elsevier Science B.V.Dissolved (DOC) and total (TOC) organic carbon concentrations and compositions were studied for several river systems in Arizona, USA. DOC composition was characterized by ultraviolet and visible absorption and fluorescence emission (excitation wavelength of 370 nm) spectra characteristics. Ephemeral sites had the highest DOC concentrations, and unregulated perennial sites had lower concentrations than unregulated intermittent sites, regulated sites, and sites downstream from wastewater-treatment plants (pwastewater-treatment plant effluent were higher in DOC concentration (pwastewater-treatment plants) was found to affect temporal variability in DOC concentration and composition.The influence of urbanization, becoming increasingly common in arid regions, on dissolved organic carbon (DOC) concentrations in surface water resources was studied. DOC concentration and composition, seasonal watershed runoff events, streamflow variations, water management practices, and urban infrastructure in several Arizona watersheds were monitored. Ephemeral sites had the highest DOC levels, and unregulated perennial sites and lower concentrations than unregulated intermittent sites, regulated sites, and sites downstream from wastewater treatment plants. Reservoir outflows

  18. Tracing the sources of organic carbon in freshwater systems

    Science.gov (United States)

    Glendell, Miriam; Meersmans, Jeroen; Barclay, Rachel; Yvon-Durocher, Gabriel; Barker, Sam; Jones, Richard; Hartley, Iain; Dungait, Jennifer; Quine, Timothy

    2016-04-01

    both terrestrial and aquatic sources as recorded in lake sediments to the measured rates of soil erosion and terrestrial & aquatic CO2 respiration rates, this study has paved a way towards a novel and cross-disciplinary approach to investigate and further improve current status of knowledge as regards C-cycling across the entire terrestrial-aquatic continuum. 137Cs was found to be useful to understand the dynamics and spatial pattern of lateral fluxes of sediment & C at the catchment scale, while tracing chemical composition of C using n-alkanes and stable isotopes (δ13C, δ15N) allowed distinguishing between the terrestrial vs. aquatic origin of C and determining main sources of particulate organic carbon in the aquatic environment within the two study catchments.

  19. Subterranean Carbon Dioxide Concentration Analysis Utilizing a Scalable Optical Fiber-Based Absorption Cell Array for Carbon Capture and Storage Site Integrity Monitoring

    Science.gov (United States)

    Wicks, G. R.; Soukup, B.; Repasky, K. S.; Carlsten, J.

    2011-12-01

    Geologic carbon sequestration is a means to mitigate the increasing atmospheric concentration of carbon dioxide (CO2) by capturing the CO2 at a source such as a power generation facility and storing the captured CO2 in geologic formations. Many technological advances will need to occur for successful carbon sequestration, including near surface monitoring tools and techniques to ensure site integrity and public safety. Researchers at Montana State University (MSU) are developing a scalable fiber sensor array in a call/return configuration for monitoring near sub-surface CO2 concentrations for the purpose of carbon sequestration site integrity monitoring. The system measures CO2 concentrations through the application of tunable diode laser absorption spectroscopy (TDLAS). The instrument utilizes four fiber probes (absorption cells) connected to a detector, a fiber-optic beam splitter, and a 1 x 4 fiber-optic micro-electromechanical (MEMS) switch that can direct the light to one of the four probes, and employs a single tunable distributed feedback (DFB) diode laser with a center wavelength of 2.004 μm to access CO2 absorption features. The fiber sensor array can easily be reconfigured by simply moving the fiber probes. Low cost is achieved by using inexpensive passive components in the probes while limiting the number of the more expensive components including the DFB laser, the detector, and the 1 X 4 MEMS switch. The fiber sensor system was tested over a sixty day period centered on a thirty day controlled CO2 release at the Zero Emission Research Technology (ZERT) facility that was developed for sub-surface and near surface carbon sequestration monitoring research. In this presentation, the design of the fiber sensor array system will be presented, along with the system performance during the sixty day monitoring experiment.

  20. The sources of atmospheric black carbon at a European gateway to the Arctic.

    Science.gov (United States)

    Winiger, P; Andersson, A; Eckhardt, S; Stohl, A; Gustafsson, Ö

    2016-01-01

    Black carbon (BC) aerosols from incomplete combustion of biomass and fossil fuel contribute to Arctic climate warming. Models-seeking to advise mitigation policy-are challenged in reproducing observations of seasonally varying BC concentrations in the Arctic air. Here we compare year-round observations of BC and its δ(13)C/Δ(14)C-diagnosed sources in Arctic Scandinavia, with tailored simulations from an atmospheric transport model. The model predictions for this European gateway to the Arctic are greatly improved when the emission inventory of anthropogenic sources is amended by satellite-derived estimates of BC emissions from fires. Both BC concentrations (R(2)=0.89, P<0.05) and source contributions (R(2)=0.77, P<0.05) are accurately mimicked and linked to predominantly European emissions. This improved model skill allows for more accurate assessment of sources and effects of BC in the Arctic, and a more credible scientific underpinning of policy efforts aimed at efficiently reducing BC emissions reaching the European Arctic. PMID:27627859

  1. [Effects of mixed carbon sources on glucose oxidase production by recombinant Pichia pastoris].

    Science.gov (United States)

    Shen, Yina; Gu, Lei; Zhang, Juan; Chen, Jian; Du, Guocheng

    2013-07-01

    Glucose oxidase (GOD) is an important industrial enzyme with many potential applications. In order to increase the production and productivity of GOD by recombinant Pichia pastoris GS115, we investigated the feeding strategies of mixed carbon sources during induction phase, based on results of the optimization of initial cell and methanol concentration on GOD production. The optimal initial cell and methanol concentration were 100 g/L and 18 g/L. During induction phase, the mixed-carbon-sources strategies showed that glycerol, sorbitol or mannitol co-feeding with methanol could enhance GOD production. With mannitol co-feeding (20:1(W/W)), the maximum GOD production and maximum GOD productivity reached 711.3 U/mL and 4.60 U/(mL x h) after an induction period of 156 h. Compared to the control, the enhancements of GOD production and productivity were 66.3% and 67.9%, respectively. Meanwhile, we found an appropriate mannitol co-feeding strategy that would not inhibit the expression of promote. The activity of alcohol oxidase was 8.8 U/g, which was enhanced by 69.2% compared to the control (5.2 U/g). We can use the same optimization process to improve the production of other proteins from recombinant Pichia pastoris by changing the fermentation parameters.

  2. Dissolved organic carbon concentrations and compositions, and trihalomethane formation potentials in waters from agricultural peat soils, Sacramento-San Joaquin Delta, California; implications for drinking-water quality

    Science.gov (United States)

    Fujii, Roger; Ranalli, Anthony J.; Aiken, George R.; Bergamaschi, Brian A.

    1998-01-01

    Water exported from the Sacramento-San Joaquin River delta (Delta) is an important drinking-water source for more than 20 million people in California. At times, this water contains elevated concentrations of dissolved organic carbon and bromide, and exceeds the U.S. Environmental Protection Agency's maximum contaminant level for trihalomethanes of 0.100 milligrams per liter if chlorinated for drinking water. About 20 to 50 percent of the trihalomethane precursors to Delta waters originates from drainage water from peat soils on Delta islands. This report elucidates some of the factors and processes controlling and affecting the concentration and quality of dissolved organic carbon released from peat soils and relates the propensity of dissolved organic carbon to form trihalomethanes to its chemical composition.Soil water was sampled from near-surface, oxidized, well-decomposed peat soil (upper soil zone) and deeper, reduced, fibrous peat soil (lower soil zone) from one agricultural field in the west central Delta over 1 year. Concentrations of dissolved organic carbon in the upper soil zone were highly variable, with median concentrations ranging from 46.4 to 83.2 milligrams per liter. Concentrations of dissolved organic carbon in samples from the lower soil zone were much less variable and generally slightly higher than samples from the upper soil zone, with median concentrations ranging from 49.3 to 82.3 milligrams per liter. The dissolved organic carbon from the lower soil zone had significantly higher aromaticity (as measured by specific ultraviolet absorbance) and contained significantly greater amounts of aromatic humic substances (as measured by XAD resin fractionation and carbon-13 nuclear magnetic resonance analysis of XAD isolates) than the dissolved organic carbon from the upper soil zone. These results support the conclusion that more aromatic forms of dissolved organic carbon are produced under anaerobic conditions compared to aerobic conditions

  3. EFFECT OF NITROGEN SOURCE AND INITIAL SUGAR CONCENTRATION ON LACTIC ACID FERMENTATION OF PINEAPPLE WASTE USING L.DELBRUECKII

    Directory of Open Access Journals (Sweden)

    Abdullah Moch Busairi

    2012-02-01

    Full Text Available The liquid pineapple waste contains mainly sucrose, glucose, fructose and other nutrients. It therefore can potentially be used as carbon source for lactic acid fermentation. The lactic acid is utilised in food technology as pH regulator, microbial preservative, buffering agent and in the chemical industry. Recently, lactic acid has been considered to be an important raw material for production of biodegradable lactate polymer. The experiments were carried out in batch fermentation at anaerobic condition with stirring speed: 50 rpm, temperature: 40 oC, pH: 6.0, and inoculum size: 5%. Effect of nitrogen source and initial sugar concentration were studied. The effect of nitrogen source on lactic acid production shows that the yeast extract is highest yield , followed by urea , corn steep liquor, malt sprout and ammonium sulphates with the yield of 78.52; 26.68; 19.14; 14.10 and 5.6 %, respectively. The highest yield of initial sugar concentration on lactic acid production obtained was 78.52 % (54.97 g/l at 70 g/l, if the concentration of sugar was increased to 110 g/l , the lactic acid production or yield decrease to51.53 g/l or 54.24%.

  4. Identifying urban sources as cause of elevated grass pollen concentrations using GIS and remote sensing

    DEFF Research Database (Denmark)

    Skjøth, Carsten Ambelas; Ørby, Pia Viuf; Becker, Thomas;

    2013-01-01

    We examine here the hypothesis that during flowering, the grass pollen concentrations at a specific site reflect the distribution of grass pollen sources within a few kilometres of this site. We perform this analysis on data from a measurement campaign in the city of Aarhus (Denmark) using three...... available remote sensing data combined with management information for local grass areas. The inventory has identified a number of grass pollen source areas present within the city domain. The comparison of the measured pollen concentrations with the inventory shows that the atmospheric concentrations...

  5. Concentrations, loads, and yields of organic carbon in streams of agricultural watersheds

    Science.gov (United States)

    Kronholm, Scott; Capel, Paul

    2012-01-01

    Carbon is cycled to and from large reservoirs in the atmosphere, on land, and in the ocean. Movement of organic carbon from the terrestrial reservoir to the ocean plays an important role in the global cycling of carbon. The transition from natural to agricultural vegetation can change the storage and movement of organic carbon in and from a watershed. Samples were collected from 13 streams located in hydrologically and agriculturally diverse watersheds, to better understand the variability in the concentrations and loads of dissolved organic carbon (DOC) and particulate organic carbon (POC) in the streams, and the variability in watershed yields. The overall annual median concentrations of DOC and POC were 4.9 (range: 2.1–6.8) and 1.1 (range: 0.4–3.8) mg C L−1, respectively. The mean DOC watershed yield (± SE) was 25 ± 6.8 kg C ha−1 yr−1. The yields of DOC from these agricultural watersheds were not substantially different than the DOC yield from naturally vegetated watersheds in equivalent biomes, but were at the low end of the range for most biomes. Total organic carbon (DOC + POC) annually exported from the agricultural watersheds was found to average 0.03% of the organic carbon that is contained in the labile plant matter and top 1 m of soil in the watershed. Since the total organic carbon exported from agricultural watersheds is a relatively small portion of the sequestered carbon within the watershed, there is the great potential to store additional carbon in plants and soils of the watershed, offsetting some anthropogenic CO2 emissions.

  6. Identifying urban sources as cause of elevated grass pollen concentrations using GIS and remote sensing

    DEFF Research Database (Denmark)

    Hertel, Ole; Skjøth, Carsten Ambelas; Orby, P.V.;

    2013-01-01

    available remote sensing data combined with management information for local grass areas. The inventory has identified a number of grass pollen source areas present within the city domain. The comparison of the measured pollen concentrations with the inventory shows that the atmospheric concentrations...... between the three urban traps and an operational trap located just 60 km away. This finding suggests that during intense flowering, the grass pollen concentration mirrors the local source distribution and is thus a local-scale phenomenon. Model simulations aimed at assessing population exposure to pollen...... levels are therefore recommended to take into account both local sources and local atmospheric transport, and not to rely only on describing regional to long-range transport of pollen. The derived pollen source inventory can be entered into local-scale atmospheric transport models in combination...

  7. Batch fermentation model of propionic acid production by Propionibacterium acidipropionici in different carbon sources.

    Science.gov (United States)

    Coral, Jefferson; Karp, Susan Grace; Porto de Souza Vandenberghe, Luciana; Parada, José Luis; Pandey, Ashok; Soccol, Carlos Ricardo

    2008-12-01

    Propionic acid (PA) is widely used as additive in animal feed and also in the manufacturing of cellulose-based plastics, herbicides, and perfumes. Salts of propionic acid are used as preservative in food. PA is mainly produced by chemical synthesis. Nowadays, PA production by fermentation of low-cost industrial wastes or renewable sources has been an interesting alternative. In the present investigation, PA production by Propionibacterium acidipropionici ATCC 4965 was studied using a basal medium with sugarcane molasses (BMSM), glycerol or lactate (BML) in small batch fermentation at 30 and 36 degrees C. Bacterial growth was carried out under low dissolved oxygen concentration and without pH control. Results indicated that P. acidipropionici produced more biomass in BMSM than in other media at 30 degrees C (7.55 g l(-1)) as well as at 36 degrees C (3.71 g l(-1)). PA and biomass production were higher at 30 degrees C than at 36 degrees C in all cases studied. The best productivity was obtained by using BML (0.113 g l(-1) h(-1)), although the yielding of this metabolite was higher when using glycerol as carbon source (0.724 g g(-1)) because there was no detection of acetic acid. By the way, when using the other two carbon sources, acetic acid emerged as an undesirable by-product for further PA purification. PMID:18386184

  8. A study of the ocean source of carbon disulphide

    Science.gov (United States)

    Xie, Huixiang

    1999-11-01

    The environmental importance of atmospheric carbon disulphide (CS 2) is recognised by its potential role as a major precursor of carbonyl Sulphide (OCS). The ocean is believed to emit CS2 to air, but large uncertainty may exist in the assessments of sea-to-air fluxes of this compound partly due to the meager database we currently have for CS2 in the ocean. This work is intended to re-assess the flux estimates and to identify and evaluate the potential Sources for Oceanic CS2. CS2 was measured in both the surface and subsurface waters during three cruises: two in the North Atlantic and one in the Pacific Ocean. All the investigated waters were supersaturated in CS2 relative to the atmosphere. Two distinct types of vertical profiles were observed: one in the cool waters of the North Atlantic, characterized by gradual reduction in CS2 with depth, and another in the warm waters of the North Pacific central are. showing the coexistence of subsurface CS2 and chlorophyll maxima. Solar UV-initiated photochemical reactions were identified as a significant source for oceanic CS2. The photo-production rate of CS2 is positively correlated with absorbance at 350 run, suggesting that the reactions are mediated by coloured dissolved organic matter. Laboratory irradiations confirmed that cysteine and cystine are efficient precursors of CS2 and that OH radicals are likely to be important intermediates. CS2 data were collected from axenic monocultures of six species of marine phytoplankton: Chaetoceros calcitrans, Phaeodactylum tricornutum, Phaeocystis sp., Porphyridium purpureum, Synechococcus sp. and Isochrysis sp. For a period of between two weeks and forty days, substantial accumulation Of CS2 was found in the cultures of C. calcitrans, P. tricornutum and Phaeocystis sp. C. calcitrans has a potential for CS2 production about 10 times higher than P. tricornutum or Phaeocystis sp. CS2 formation was strongly dependent on the growth stage of the cultured species. (Abstract shortened

  9. Reduction of formaldehyde concentrations in the air and cadaveric tissues by ammonium carbonate

    OpenAIRE

    Kawamata, Seiichi; Kodera, Haruo

    2004-01-01

    The reduction of formaldehyde by ammonium carbonate was examined in cadavers and in vitro. Formaldehyde concentrations in the air (10 cm above human cadavers) and in various cadaveric tissues were measured with or without perfusion of ammonium carbonate solution into formaldehyde-fixed cadavers. Air samples were monitored using Kitagawa gas detector tubes. For measurement of formaldehyde in tissues, muscles and organs were cut into small pieces and tissue fluids were separated out by centrifu...

  10. Carbon nanotube based field emission X-ray sources

    Science.gov (United States)

    Cheng, Yuan

    This dissertation describes the development of field emission (FE) x-ray sources with a carbon-nanotube (CNT) cathode. Field emission x-rays have advantages over conventional x-rays by replacing the thermionic cathode with a cold cathode so that electrons are emitted at room temperature and emission is voltage controllable. CNTs are found to be excellent electron emitters with low threshold fields and high current density which makes them ideal for generate field emission x-rays. Macroscopic CNT cold cathodes are prepared and the parameters to tune their field emission properties are studied: structure and morphology of CNT cathodes, temperature as well as electronic work function of CNT. Macroscopic CNT cathodes with optimized performance are chosen to build a high-resolution x-ray imaging system. The system can readily generate x-ray radiation with continuous variation of temporal resolution up to nanoseconds and spatial resolution down to 10 micron. Its potential applications for dynamic x-ray imaging and micro-computed tomography are also demonstrated. The performance characteristics of this compact and versatile system are promising for non-destructive testing and for non-invasive small-animal imaging for biomedical research.

  11. Carbonic anhydrase levels and internal lacunar CO/sub 2/ concentrations in aquatic macrophytes

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, C.I.

    1979-01-01

    Carbonic anhydrase levels were examined in a variety of aquatic macrophytes from different habitats. In general, carbonic anhydrase levels increased across the habitat gradient such that activities were low in submersed aquatic macrophytes and high in emergent macrophytes with floating-leaved and free-floating plants exhibiting intermediate activities. Internal lacunar CO/sub 2/ concentrations were analyzed in relation to carbonic anhydrase activities. There was no correlation between these two parameters. Internal CO/sub 2/ concentrations ranged from low to high in submersed macrophytes, but were low in floating-leaved and emergent macrophytes. The observed internal CO/sub 2/ concentrations are discussed in relation to the individual morphologies of the plants and the environments in which they occurred.

  12. Dynamic responses of atmospheric carbon dioxide concentration to global temperature changes between 1850 and 2010

    Science.gov (United States)

    Wang, Weile; Nemani, Ramakrishna

    2016-02-01

    Changes in Earth's temperature have significant impacts on the global carbon cycle that vary at different time scales, yet to quantify such impacts with a simple scheme is traditionally deemed difficult. Here, we show that, by incorporating a temperature sensitivity parameter (1.64 ppm yr-1 °C-1) into a simple linear carbon-cycle model, we can accurately characterize the dynamic responses of atmospheric carbon dioxide (CO2) concentration to anthropogenic carbon emissions and global temperature changes between 1850 and 2010 ( r 2 > 0.96 and the root-mean-square error CO2 concentration (~15 ppm °C-1), generally consistent with previous estimates based on reconstructed CO2 and climate records over the Little Ice Age. Our results suggest that recent increases in global surface temperatures, which accelerate the release of carbon from the surface reservoirs into the atmosphere, have partially offset surface carbon uptakes enhanced by the elevated atmospheric CO2 concentration and slowed the net rate of atmospheric CO2 sequestration by global land and oceans by ~30% since the 1960s. The linear modeling framework outlined in this paper thus provides a useful tool to diagnose the observed atmospheric CO2 dynamics and monitor their future changes.

  13. Source Contribution Analysis of Surface Particulate Polycyclic Aromatic Hydrocarbon Concentrations in Northeastern Asia by Source-receptor Relationships

    Energy Technology Data Exchange (ETDEWEB)

    Inomata, Yayoi; Kajino, Mizuo; Sato, Keiichi; Ohara, Toshimasa; Kurokawa, Jun-Ichi; Ueda, Hiromasa; Tang, Ning; Hayakawa, Kazuichi; Ohizumi, Tsuyoshi; Akimoto, Hajime

    2013-11-01

    We analyzed the sourceereceptor relationships for particulate polycyclic aromatic hydrocarbon (PAH) concentrations in northeastern Asia using an aerosol chemical transport model. The model successfully simulated the observed concentrations. In Beijing (China) benzo[a]pyren (BaP) concentrations are due to emissions from its own domain. In Noto, Oki and Tsushima (Japan), transboundary transport from northern China (>40°N, 40-60%) and central China (30-40°N, 10-40%) largely influences BaP concentrations from winter to spring, whereas the relative contribution from central China is dominant (90%) in Hedo. In the summer, the contribution from Japanese domestic sources increases (40-80%) at the 4 sites. Contributions from Japan and Russia are additional source of BaP over the northwestern Pacific Ocean in summer. The contribution rates for the concentrations from each domain are different among PAH species depending on their particulate phase oxidation rates. Reaction with O3 on particulate surfaces may be an important component of the PAH oxidation processes.

  14. Spatiotemporally resolved black carbon concentration, schoolchildren's exposure and dose in Barcelona.

    Science.gov (United States)

    Rivas, I; Donaire-Gonzalez, D; Bouso, L; Esnaola, M; Pandolfi, M; de Castro, M; Viana, M; Àlvarez-Pedrerol, M; Nieuwenhuijsen, M; Alastuey, A; Sunyer, J; Querol, X

    2016-06-01

    At city level, personal monitoring is the best way to assess people's exposure. However, it is usually estimated from a few monitoring stations. Our aim was to determine the exposure to black carbon (BC) and BC dose for 45 schoolchildren with portable microaethalometers and to evaluate the relationship between personal monitoring and fixed stations at schools (indoor and outdoor) and in an urban background (UB) site. Personal BC concentra-tions were 20% higher than in fixed stations at schools. Linear mixed-effect models showed low R(2) between personal measurements and fixed stations at schools (R(2)  ≤ 0.28), increasing to R(2)  ≥ 0.70 if considering only periods when children were at schools. For the UB station, the respective R(2) were 0.18 and 0.45, indicating the importance of the distance to the monitoring station when assessing exposure. During the warm season, the fixed stations agreed better with personal measurements than during the cold one. Children spent 6% of their time on commuting but received 20% of their daily BC dose, due to co-occurrence with road traffic rush hours and the close proximity to the source. Children received 37% of their daily-integrated BC dose at school. Indoor environments (classroom and home) were responsible for the 56% BC dose. PMID:25924870

  15. Effects of Citric Acid Concentration and Activation Temperature on the Synthesis of Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    Fengyi Li; Minwei Wang; Rongbin Zhang; Renzhong Wei; Niancai Peng

    2004-01-01

    A series of Ni-La-Mg catalyst samples were prepared by citric acid complex method, and carbon nanotubes were synthesized by catalytic decomposition of CH4 on these catalysts. The effects of the citric acid concentration and the activation temperature on catalytic activity were investigated by CO adsorption,TEM and XRD techniques. The experimental results showed that the particle size of the catalysts prepared through gel auto-combustion varied with the concentration of citric acid. Therefore carbon nanotubes with different diameters were obtained correspondingly. The effect of activation temperature on the activity of catalyst was negligible from 500 to 700 ℃, but it became pronounced at lower or higher temperatures.

  16. A century of human-driven changes in the carbon dioxide concentration of lakes

    Science.gov (United States)

    Perga, Marie-Elodie; Maberly, Stephen C.; Jenny, Jean-Philippe; Alric, Benjamin; Pignol, Cécile; Naffrechoux, Emmanuel

    2016-02-01

    Now that evasion of carbon dioxide (CO2) from inland waters is accounted for in global carbon models, it is crucial to quantify how these fluxes have changed in the past and forecast how they may alter in the future in response to local and global change. Here we developed a sediment proxy for the concentration of summer surface dissolved CO2 concentration and used it to reconstruct changes over the past 150 years for three large lakes that have been affected by climate warming, changes in nutrient load, and detrital terrigenous supplies. Initially CO2 neutral to the atmosphere, all three lakes subsequently fluctuated between near equilibrium and supersaturation. Although catchment inputs have supplied CO2 to the lakes, internal processes and reallocation have ultimately regulated decadal changes in lake surface CO2 concentration. Nutrient concentration has been the dominant driver of CO2 variability for a century although the reproducible, nonmonotonic relationship of CO2 to nutrient concentration suggests an interplay between metabolic and chemical processes. Yet for two of these lakes, climatic control of CO2 concentrations has been important over the last 30 years, promoting higher surface CO2 concentrations, likely by decreasing hypolimnetic carbon storage. This new approach offers the unique opportunity to scale, a posteriori, the long-term impact of human activities on lake CO2.

  17. Rapid biological oxidation of methanol in the tropical Atlantic: significance as a microbial carbon source

    Directory of Open Access Journals (Sweden)

    J. L. Dixon

    2011-04-01

    Full Text Available Methanol is the second most abundant organic gas in the atmosphere after methane, and is ubiquitous in the troposphere. It plays a significant role in atmospheric oxidant chemistry and is biogeochemically active. Large uncertainties exist about whether the oceans are a source or sink of methanol to the atmosphere. Even less is understood about what reactions in seawater determine its concentration, and hence flux across the sea surface interface. We report here concentrations of methanol up to 300 nM, with corresponding microbial uptake rates between 2–146 nM d−1, suggesting turnover times as low as 1 day in surface waters of the oligotrophic tropical North East Atlantic. Comparisons with parallel determinations of bacterial leucine uptake suggest that methanol contributes on average 13% to bacterial carbon demand in the central northern Atlantic gyre (maximum of 54%. However, our low air to sea methanol flux estimates of 7.2–13 μmol m−2 d−1 suggest that the atmosphere is not a major source. We conclude that there must be a major, as yet unidentified, in situ oceanic methanol source in these latitudes which we suggest is sunlight driven decomposition of organic matter.

  18. Ablation Properties of the Carbon-Based Composites Used in Artificial Heat Source Under Fire Accident

    Institute of Scientific and Technical Information of China (English)

    TANG; Xian; HUANG; Jin-ming; ZHOU; Shao-jian; LUO; Zhi-fu

    2012-01-01

    <正>The ablation properties of the carbon-based composites used in artificial heat source under fire accident were investigated by the arc heater. In this work, we tested the carbon-based composites referring to Fig. 1. Their linear/mass ablation ratio and ablation morphologies were studied. The results showed that the carbon-based composites used in artificial heat source behaved well

  19. Slow strain rate testing of carbon steel in solutions with high nitrate concentrations

    International Nuclear Information System (INIS)

    Processing of high-level nuclear waste for permanent disposal will cause changes to the present inhibited compositions at the Savannah River Site. Temperature and nitrate concentration may reach new high levels during salt dissolution in the carbon steel waste tanks with certain removal methods. Proper inhibitor concentrations are necessary to minimize the potential for nitrate-induced stress corrosion cracking to maintain the integrity of the waste tanks. Slow strain rate testing and potentiodynamic polarization were used to investigate whether stress corrosion cracking would initiate under bounding removal conditions. Test conditions for two carbon steels included nitrate concentrations of 5.5 and 9.7 M at a maximum temperature of 95 degrees C. The steels were found to be resistant to SCC in the more aggressive waste compositions at the present inhibitor concentrations of 0.6 M sodium hydroxide and 0.5 M sodium nitrite

  20. Modeling Aerobic Carbon Source Degradation Processes using Titrimetric Data and Combined Respirometric-Titrimetric Data: Structural and Practical Identifiability

    DEFF Research Database (Denmark)

    Gernaey, Krist; Petersen, B.; Dochain, D.;

    2002-01-01

    considerably more for dextrose than for acetate degradation models. Noteworthy is the finding that the half-saturation substrate concentrations can be different depending on whether they are estimated from respirometric or titrimetric data. Moreover, this difference appears to be dependent on the carbon source...... the initial substrate concentration S-S(O) is known. The values found correspond to values reported in literature, but, interestingly, also seem able to reflect the occurrence of storage processes when pulses of acetate and dextrose are added. (C) 2002 Wiley Periodicals, Inc.......The structural and practical identifiability of a model for description of respirometric-titrimetric data derived from aerobic batch substrate degradation experiments of a CxHyOz carbon source with activated sludge was evaluated. The model processes needed to describe titrimetric data included...

  1. Investigating effectiveness of activated carbons of natural sources on various supercapacitors

    Science.gov (United States)

    Faisal, Md. Shahnewaz Sabit; Rahman, Muhammad M.; Asmatulu, Ramazan

    2016-04-01

    Activated carbon can be produced from natural sources, such as pistachio and acorn shells, which can be an inexpensive and sustainable sources of natural wastes for the energy storage devices, such as supercapacitors. The carbonaceous materials used in this study were carbonized at the temperatures of 700°C and 900°C after the stabilization process at 240°C for two hours. These shells showed approximately 60% carbon yield. Carbonized nutshells were chemically activated using1wt% potassium hydroxide (KOH). Activated carbon powders with polyvinylidene fluoride (PVdF) were used to construct carbon electrodes. A 1M of tetraethylammonium tetrafluoroborate (TEABF4) and propylene carbonate (PC) were used as electrolytes. Electrochemical techniques, such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used for the characterization of the supercapacitors. Scanning electron microscopy (SEM) was used to inspect the surface texture of the activated carbons. Activated pistachio shells carbonized at 700°C showed more porous surface texture than those carbonized at 900°C. Effects of the carbonization temperatures were studied for their electrochemical characteristics. The shells carbonized at 700°C showed better electrochemical characteristics compared to those carbonized at 900°C. The test results provided about 27,083 μF/g specific capacitance at a scan rate of 10mV/s. This study showed promising results for using these activated carbons produced from the natural wastes for supercapacitor applications.

  2. Boreal Lake Sediments as Sources and Sinks of Carbon

    OpenAIRE

    Gudasz, Cristian

    2011-01-01

    Inland waters process large amounts of organic carbon, contributing to CO2 and CH4 emissions, as well as storing organic carbon (OC) over geological timescales. Recently, it has been shown that the magnitude of these processes is of global significance. It is therefore important to understand what regulates OC cycling in inland waters and how is that affected by climate change. This thesis investigates the constraints on microbial processing of sediment OC, as a key factor of the carbon cycli...

  3. Comparative study on bacterial carbon sources in lake sediments: the role of methanotrophy

    OpenAIRE

    Steger, K.; K. Premke; Gudasz, C.; Boschker, H.T.S.; Tranvik, L.J.

    2015-01-01

    Methane-derived carbon can be important in both benthic and pelagic food webs.Either generated in the anaerobic layers of the sediment or in the anaerobic hypolimnion of stratifiedeutrophic lakes, methane is an excellent carbon source for aerobic methanotrophic bacteria.The very negative methane d13C-signal in the methanotrophic biomass provides an excellentopportunity to trace the use of methane-derived carbon in food webs. We studied carbon sourcesof benthic bacteria in a range of Swedish l...

  4. Prediction of soil organic carbon concentration and soil bulk density of mineral soils for soil organic carbon stock estimation

    Science.gov (United States)

    Putku, Elsa; Astover, Alar; Ritz, Christian

    2016-04-01

    Soil monitoring networks provide a powerful base for estimating and predicting nation's soil status in many aspects. The datasets of soil monitoring are often hierarchically structured demanding sophisticated data analyzing methods. The National Soil Monitoring of Estonia was based on a hierarchical data sampling scheme as each of the monitoring site was divided into four transects with 10 sampling points on each transect. We hypothesized that the hierarchical structure in Estonian Soil Monitoring network data requires a multi-level mixed model approach to achieve good prediction accuracy of soil properties. We used this database to predict soil bulk density and soil organic carbon concentration of mineral soils in arable land using different statistical methods: median approach, linear regression and mixed model; additionally, random forests for SOC concentration. We compared the prediction results and selected the model with the best prediction accuracy to estimate soil organic carbon stock. The mixed model approach achieved the best prediction accuracy in both soil organic carbon (RMSE 0.22%) and bulk density (RMSE 0.09 g cm-3) prediction. Other considered methods under- or overestimated higher and lower values of soil parameters. Thus, using these predictions we calculated the soil organic carbon stock of mineral arable soils and applied the model to a specific case of Tartu County in Estonia. Average estimated SOC stock of Tartu County is 54.8 t C ha-1 and total topsoil SOC stock 1.8 Tg in humus horizon.

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

    Science.gov (United States)

    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 (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.

  6. Soil concentrations, occurrence, sources and estimation of air-soil exchange of polychlorinated biphenyls in Indian cities.

    Science.gov (United States)

    Chakraborty, Paromita; Zhang, Gan; Li, Jun; Selvaraj, Sakthivel; Breivik, Knut; Jones, Kevin C

    2016-08-15

    Past studies have shown potentially increasing levels of polychlorinated biphenyls (PCBs) in the Indian environment. This is the first attempt to investigate the occurrence of PCBs in surface soil and estimate diffusive air-soil exchange, both on a regional scale as well as at local level within the metropolitan environment of India. From the north, New Delhi and Agra, east, Kolkata, west, Mumbai and Goa and Chennai and Bangalore in the southern India were selected for this study. 33 PCB congeners were quantified in surface soil and possible sources were derived using positive matrix factorization model. Net flux directions of PCBs were estimated in seven major metropolitan cities of India along urban-suburban-rural transects. Mean Σ33PCBs concentration in soil (12ng/g dry weight) was nearly twice the concentration found in global background soil, but in line with findings from Pakistan and urban sites of China. Higher abundance of the heavier congeners (6CB-8CB) was prevalent mostly in the urban centers. Cities like Chennai, Mumbai and Kolkata with evidence of ongoing PCB sources did not show significant correlation with soil organic carbon (SOC). This study provides evidence that soil is acting as sink for heavy weight PCB congeners and source for lighter congeners. Atmospheric transport is presumably a controlling factor for occurrence of PCBs in less polluted sites of India. PMID:27136304

  7. Acute phase IL-10 plasma concentration associates with the high risk sources of cardiogenic stroke.

    Directory of Open Access Journals (Sweden)

    Otso Arponen

    Full Text Available Etiological assessment of stroke is essential for accurate treatment decisions and for secondary prevention of recurrence. There is evidence that interleukin-10 (IL-10 associates with ischemic stroke. The aim of this prospective study was to assess the levels of IL-10 in ischemic stroke with unknown or suspected cardiogenic etiology, and evaluate the correlation between IL-10 plasma concentration and the number of diagnosed high risk sources for cardioembolism.A total of 141 patients (97 males; mean age 61±11 years with acute ischemic stroke with unknown etiology or suspected cardiogenic etiology other than known atrial fibrillation (AF underwent imaging investigations to assess high risk sources for cardioembolic stroke established by the European Association of Echocardiography (EAE. IL-10 was measured on admission to the hospital and on a three month follow-up visit.Acute phase IL-10 concentration was higher in patients with EAE high risk sources, and correlated with their number (p<0.01. In patients with no risk sources (n = 104, the mean IL-10 concentration was 2.7±3.1 ng/L (range 0.3-16.3 ng/L, with one risk source (n = 26 3.7±5.5 ng/L (0.3-23.6 ng/L, with two risk sources (n = 10 7.0±10.0 ng/L (1.29-34.8 ng/L and with three risk sources (n = 1 37.2 ng/L. IL-10 level was not significantly associated with cerebral infarct volume, presence of previous or recent myocardial infarction, carotid/vertebral artery atherosclerosis, paroxysmal AF registered on 24-hour ECG Holter monitoring or given intravenous thrombolytic treatment.IL-10 plasma concentration correlates independently with the number of EAE cardioembolic risk sources in patients with acute stroke. IL-10 may have potential to improve differential diagnostics of stroke with unknown etiology.

  8. Integrated Data Fusion and Mining Techniques for Monitoring Total Organic Carbon Concentrations in a Lake

    Science.gov (United States)

    Total organic carbon (TOC) in surface waters, markedly of seasonal variations, is a known precursor of disinfection byproducts such as Total Trihalomethanes (TTHM) in drinking water treatment. Real-time knowledge of TOC distribution in source water can help treatment operation to...

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

    Science.gov (United States)

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

    2016-01-01

    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. PMID:27251365

  10. Temporal Variation of Carbon Monoxide Concentration at Congested Urban Roadways Intersection

    Directory of Open Access Journals (Sweden)

    Ghanshyam

    2014-01-01

    Full Text Available The carbon monoxide (CO is dominant among major traffic emitted pollutants such as respirable suspended particulate matter (RSPM, oxides of nitrogen (NOx, volatile organic carbons(VOCs and ozone (O3 etc. It is generated by automobiles due to incomplete combustion of the fuel. The vehicles that queue up at an intersection spend more time in idle driving mode generating more pollutant leading to higher pollutant concentrations. Therefore, the trends of average hourly CO concentrations at various locations of congested roadways intersection have been investigated. The four approach roads making intersection have been selected for the present study. CO monitoring has been carried out at 2 selected locations of each approach road. The CO concentration has been monitored from 8:00 AM to 8:00 PM at each location using portable online CO monitor. The average hourly CO concentrations data have been analyzed using MS excel spread sheet for each approach road. The average hourly concentration of monitored CO concentration at all receptors locations shows two peak CO concentration values (i.e., the morning peak and evening peak throughout the monitoring programme (March to May, 2011. The comparison of monitored values of average 1 hourly CO concentration levels as well as 8 hourly average concentration levels of CO showed non compliance with the prescribed standards (4000 µg/m3 average hourly and 2000 µg/m3 average 8 hourly CO concentration. The temporal CO concentration at various approach roads making roadway intersection shows non-uniform. The highest CO concentration has been observed to be towards high rise building and vice-versa. The least CO concentration has been observed towards either low rise building or open area.

  11. Effect of plant photosynthesis, carbon sources and ammonium availability on nitrogen fixation rates in the rhizosphere of Zostera noltii

    OpenAIRE

    Welsh, Dt; Bourgues, S; Dewit, R; Auby, Isabelle

    1997-01-01

    Rates of nitrogen fixation (measured as acetylene reduction) in the rhizosphere of the seagrass Zostera noltii were highly dependent upon plant photosynthetic activity being significantly stimulated at elevated CO2 concentrations and by light, both in the short-term and over diurnal cycles. Stimulation by light became insignificant when 5 mM sucrose was added to the sediment porewater, indicating that in the absence of added carbon sources, light stimulation was due to direct inputs of plant ...

  12. Influence of carbon source and temperature on the denitrifying phosphorus removal process

    Institute of Scientific and Technical Information of China (English)

    WANG Yayi; WANG Shuying; PENG Yongzhen; Zhu Guibing; LING Yunfang

    2007-01-01

    To supply the valuable operating parameters for the popular usage of the new denitrifying phosphors removal process,it is essential to study the dominant biochemical reactions and the characteristics of denitriflying phosphorus removing bacteria(DPB).Thus,parallel batch experiments using DPB sludge were carried out to assess the effect of substrates(sewage,HAc,and endogenous carbon source)on denitriflying dephosphorus removal efficiency in this study.The results showed that the initial specific phosphorus release rate increased with the high concentration of the short-chain volatile fatty acids ratio in the influent,and sufficient phosphorus was released by DPB.This improved the subsequent denitrification and phosphorus uptake efficiency.The specific endogenous denitrification mainly relies on the internal carbon source(PHB)stored by poly-P bacteria.Denitrifying phosphorus removing bacteria were very hungry when the internal PHB was consumed.Consequently,the specific endogenous denitrification rate was low and the phosphorus uptake did not happen.On the other hand,in the experiment,the denitrifying phosphorus removal performance under two temperature conditions(8-10℃ and 25-26℃)was also investigated and analyzed.It was found that the lower temperature decreased the specific phosphorus release and uptake rate,but did not inhibit the denitrifying phosphorus removal completely.Therefore,the negative influence of the low temperature on the overall phosphorus removal was not significant.

  13. Reduction of nitrous oxide emissions from partial nitrification process by using innovative carbon source (mannitol).

    Science.gov (United States)

    Zhang, Xinwen; Wang, Xiaoqing; Zhang, Jian; Huang, Xiaoyu; Wei, Dong; Lan, Wei; Hu, Zhen

    2016-10-01

    The purpose of this study was to evaluate the effect of mannitol as carbon source on nitrogen removal and nitrous oxide (N2O) emission during partial nitrification (PN) process. Laboratory-scale PN sequencing batch reactors (SBRs) were operated with mannitol and sodium acetate as carbon sources, respectively. Results showed that mannitol could remarkably reduce N2O-N emission by 41.03%, without influencing the removal efficiency of NH4(+)-N. However, it has a significant influence on nitrite accumulation ratio (NAR) and TN removal, which were 19.97% and 13.59% lower than that in PN with sodium acetate, respectively. Microbial analysis showed that the introduction of mannitol could increase the abundance of bacteria encoding nosZ genes. In addition, anti-oxidant enzymes (T-SOD, POD and CAT) activities were significantly reduced and the dehydrogenase activity had an obvious increase in mannitol system, indicating that mannitol could alleviate the inhibition of N2O reductase (N2OR) activities caused by high NO2(-)-N concentration. PMID:27423546

  14. Rising atmospheric CO2 is reducing the protein concentration of a floral pollen source essential for North American bees.

    Science.gov (United States)

    Ziska, Lewis H; Pettis, Jeffery S; Edwards, Joan; Hancock, Jillian E; Tomecek, Martha B; Clark, Andrew; Dukes, Jeffrey S; Loladze, Irakli; Polley, H Wayne

    2016-04-13

    At present, there is substantive evidence that the nutritional content of agriculturally important food crops will decrease in response to rising levels of atmospheric carbon dioxide, Ca However, whether Ca-induced declines in nutritional quality are also occurring for pollinator food sources is unknown. Flowering late in the season, goldenrod (Solidago spp.) pollen is a widely available autumnal food source commonly acknowledged by apiarists to be essential to native bee (e.g. Bombus spp.) and honeybee (Apis mellifera) health and winter survival. Using floral collections obtained from the Smithsonian Natural History Museum, we quantified Ca-induced temporal changes in pollen protein concentration of Canada goldenrod (Solidago canadensis), the most wide spread Solidago taxon, from hundreds of samples collected throughout the USA and southern Canada over the period 1842-2014 (i.e. a Ca from approx. 280 to 398 ppm). In addition, we conducted a 2 year in situtrial of S. Canadensis populations grown along a continuous Ca gradient from approximately 280 to 500 ppm. The historical data indicated a strong significant correlation between recent increases in Ca and reductions in pollen protein concentration (r(2)= 0.81). Experimental data confirmed this decrease in pollen protein concentration, and indicated that it would be ongoing as Ca continues to rise in the near term, i.e. to 500 ppm (r(2)= 0.88). While additional data are needed to quantify the subsequent effects of reduced protein concentration for Canada goldenrod on bee health and population stability, these results are the first to indicate that increasing Ca can reduce protein content of a floral pollen source widely used by North American bees. PMID:27075256

  15. Rising atmospheric CO2 is reducing the protein concentration of a floral pollen source essential for North American bees.

    Science.gov (United States)

    Ziska, Lewis H; Pettis, Jeffery S; Edwards, Joan; Hancock, Jillian E; Tomecek, Martha B; Clark, Andrew; Dukes, Jeffrey S; Loladze, Irakli; Polley, H Wayne

    2016-04-13

    At present, there is substantive evidence that the nutritional content of agriculturally important food crops will decrease in response to rising levels of atmospheric carbon dioxide, Ca However, whether Ca-induced declines in nutritional quality are also occurring for pollinator food sources is unknown. Flowering late in the season, goldenrod (Solidago spp.) pollen is a widely available autumnal food source commonly acknowledged by apiarists to be essential to native bee (e.g. Bombus spp.) and honeybee (Apis mellifera) health and winter survival. Using floral collections obtained from the Smithsonian Natural History Museum, we quantified Ca-induced temporal changes in pollen protein concentration of Canada goldenrod (Solidago canadensis), the most wide spread Solidago taxon, from hundreds of samples collected throughout the USA and southern Canada over the period 1842-2014 (i.e. a Ca from approx. 280 to 398 ppm). In addition, we conducted a 2 year in situtrial of S. Canadensis populations grown along a continuous Ca gradient from approximately 280 to 500 ppm. The historical data indicated a strong significant correlation between recent increases in Ca and reductions in pollen protein concentration (r(2)= 0.81). Experimental data confirmed this decrease in pollen protein concentration, and indicated that it would be ongoing as Ca continues to rise in the near term, i.e. to 500 ppm (r(2)= 0.88). While additional data are needed to quantify the subsequent effects of reduced protein concentration for Canada goldenrod on bee health and population stability, these results are the first to indicate that increasing Ca can reduce protein content of a floral pollen source widely used by North American bees.

  16. Low powdered activated carbon concentrations to improve MBR sludge filterability at high salinity and low temperature

    NARCIS (Netherlands)

    Remy, M.J.J.; Temmink, B.G.; Brink, van den P.; Rulkens, W.H.

    2011-01-01

    Previous research has demonstrated that powdered activated carbon (PAC), when applied at very low dosages and long SRTs, reduces membrane fouling in membrane bioreactor (MBRs). This effect was related to stronger flocs which are less sensitive to shear. Low temperature and high salt concentration ar

  17. Linking CDOM spectral absorption to dissolved organic carbon concentrations and loadings in boreal estuaries

    DEFF Research Database (Denmark)

    Asmala, Eero; Stedmon, Colin A.; Thomas, David N.

    2012-01-01

    The quantity of chromophoric dissolved organic matter (CDOM) and dissolved organic carbon (DOC) in three Finnish estuaries (Karjaanjoki, Kyrönjoki and Kiiminkijoki) was investigated, with respect to predicting DOC concentrations and loadings from spectral CDOM absorption measurements. Altogether 87...

  18. Measurement of low concentration and nano-quantity hydrogen sulfide in sera using unfunctionalized carbon nanotubes

    International Nuclear Information System (INIS)

    Hydrogen sulfide (H2S) is produced in small amounts by certain cells in the mammalian body and has a number of biological functions. H2S gas naturally produced by the body is not simply a toxic gas; it could be a vascular dilator and play a physiological role in regulating cardiovascular functions. In order to know the effects of H2S, it is necessary to accurately know its concentrations in the body. Conventional measurement methods have their limitations concerning the small amount and low concentration of H2S in the body. A new paradigm of using carbon nanotubes in H2S measurement expresses its potential. However, the influence of proteins in the mammalian body must be studied in the measurement of H2S by carbon nanotubes. In this paper, we demonstrate a successful measurement of low concentration (20 µM) and nano-quantity (0.5 µg) H2S in the serum by using carbon nanotubes and further with the fluorescence of confocal laser scanning microscopy and the luminescence of Raman microscopy. Statistical analysis of the experimental data shows that the relationship between concentrations and intensities is linear, which thus makes the carbon nanotube sensor highly promising for the measurement of H2S in sera

  19. The determination of hydroxide and carbonate in concentrated sodium chloride solutions

    NARCIS (Netherlands)

    Roolvink, W.B.; Bos, M.

    1980-01-01

    A computer method for the determination of carbonate and hydroxide in concentrated (2.89 M) sodium chloride solutions is described. The method is based on multiparametric curve-fitting and can also be applied to salts of dibasic acids with unknown equilibrium constants. The systematic error is not m

  20. Photosynthesis in tropical cover crop legumes influenced by irradiance, external carbon dioxide concentration and temperature

    Science.gov (United States)

    In plantation crops perennial tropical legumes are grown as understory plants, receive limited irradiance, and are subjected to elevated levels of CO2 and temperature. Independent short-term effects of photosynthetic photon flux density (PPFD), external carbon dioxide concentration [CO2] and temper...

  1. Food sources for the mangrove tree crab aratus pisonii: a carbon isotopic study

    International Nuclear Information System (INIS)

    Muscle tissues from the mangrove tree crab Aratus pisonii was analysed for carbon isotopic composition, in order to trace its major food sources. Potential food sources: mangrove leaves epi phytic green algae, mangrove sediments and open water and mangrove suspended matter; were also analysed. The results show that A. pisonii is basically omnivorous, with major food sources from marine origin. However, mangrove carbon can contribute with 16% to 42% in the crab's diet. (author)

  2. Polycyclic aromatic hydrocarbons in urban street dust and surface soil: comparisons of concentration, profile, and source.

    Science.gov (United States)

    Wang, De-Gao; Yang, Meng; Jia, Hong-Liang; Zhou, Lei; Li, Yi-Fan

    2009-02-01

    Street dust and surface soil samples in urban areas of Dalian, a coastal city in Liaoning Province, China, were collected and analyzed for 25 polycyclic aromatic hydrocarbons (PAHs). The concentrations, distribution, and sources of PAHs in dust and soil were determined. The concentrations of total PAHs in street dust ranged between 1890 and 17,070 ng/g (dry weight), with an average of 7460 ng/g, whereas the concentrations of total PAHs in surface soil varied greatly, from 650 to 28,900 ng/g, with a mean value of 6440 ng/g. Statistical paired t-test confirmed that total PAH concentrations have no significant difference between street dust and surface soil. Mean PAH concentrations in two type samples were much higher at industrial sites than at business/residential or garden sites. PAHs were dominated by higher molecular weight PAH (4- to 6-ring) homologues, which accounted for about 73% and 72% of total PAHs in street dust and surface soil, respectively. Principal component analysis was used in source apportionment of PAHs in dust and soil. Pyrogenic and petrogenic sources contributed 70% and 22.4% of total PAHs in street dusts, and fossil fuel (coal and petroleum) and biomass combustion accounted for 64.4% and 5.6% of total PAHs in pyrogenic sources, respectively. In surface soil, total PAHs were dominated by pyrogenic sources. The diagnostic ratios of benz[a]anthracene/chrysene confirmed that PAHs in street dust and surface soil of a Dalian urban zone might come mostly from the emission of local sources.

  3. Effects of increasing seawater carbon dioxide concentrations on chain formation of the diatom Asterionellopsis glacialis.

    Directory of Open Access Journals (Sweden)

    Joana Barcelos e Ramos

    Full Text Available Diatoms can occur as single cells or as chain-forming aggregates. These two strategies affect buoyancy, predator evasion, light absorption and nutrient uptake. Adjacent cells in chains establish connections through various processes that determine strength and flexibility of the bonds, and at distinct cellular locations defining colony structure. Chain length has been found to vary with temperature and nutrient availability as well as being positively correlated with growth rate. However, the potential effect of enhanced carbon dioxide (CO2 concentrations and consequent changes in seawater carbonate chemistry on chain formation is virtually unknown. Here we report on experiments with semi-continuous cultures of the freshly isolated diatom Asterionellopsis glacialis grown under increasing CO2 levels ranging from 320 to 3400 µatm. We show that the number of cells comprising a chain, and therefore chain length, increases with rising CO2 concentrations. We also demonstrate that while cell division rate changes with CO2 concentrations, carbon, nitrogen and phosphorus cellular quotas vary proportionally, evident by unchanged organic matter ratios. Finally, beyond the optimum CO2 concentration for growth, carbon allocation changes from cellular storage to increased exudation of dissolved organic carbon. The observed structural adjustment in colony size could enable growth at high CO2 levels, since longer, spiral-shaped chains are likely to create microclimates with higher pH during the light period. Moreover increased chain length of Asterionellopsis glacialis may influence buoyancy and, consequently, affect competitive fitness as well as sinking rates. This would potentially impact the delicate balance between the microbial loop and export of organic matter, with consequences for atmospheric carbon dioxide.

  4. Satellite observations of seasonal and regional variability of particulate organic carbon concentration in the Barents Sea

    Science.gov (United States)

    Stramska, Malgorzata; Białogrodzka, Jagoda

    2016-04-01

    The Nordic and Barents Seas are of special interest for research on climate change, since they are located on the main pathway of the heat transported from low to high latitudes. Barents Sea is known to be an important area for formation of deep water and significant uptake from the atmosphere and sequestration of carbon dioxide (CO2). This region is characterized by supreme phytoplankton blooms and large amount of carbon is sequestered here due to biological processes. It is important to monitor the biological variability in this region in order to derive in depth understanding whether the size of carbon reservoirs and fluxes may vary as a result of climate change. In this presentation we analyze the 17 years (1998-2014) of particulate organic carbon (POC) concentration derived from remotely sensed ocean color. POC concentrations in the Barents Sea are among the highest observed in the global ocean with monthly mean concentrations in May exceeding 300 mg m-3. The seasonal amplitude of POC concentration in this region is larger when compared to other regions in the global ocean. Our results indicate that the seasonal increase in POC concentration is observed earlier in the year and higher concentrations are reached in the southeastern part of the Barents Sea in comparison to the southwestern part. Satellite data indicate that POC concentrations in the southern part of the Barents Sea tend to decrease in recent years, but longer time series of data are needed to confirm this observation. This work was funded by the Norway Grants (NCBR contract No. 201985, project NORDFLUX). Partial support for MS comes from the Institute of Oceanology (IO PAN).

  5. Atmospheric speciated mercury concentrations on an island between China and Korea: sources and transport pathways

    Directory of Open Access Journals (Sweden)

    G.-S. Lee

    2015-11-01

    Full Text Available As a global pollutant, mercury (Hg is of particular concern in East Asia where anthropogenic emissions are the largest. In this study, speciated Hg concentrations were measured in the western most island in Korea, located between China and the Korean mainland to identify the importance of local, regional and distant Hg sources. Various tools including correlations with other pollutants, conditional probability function, and back-trajectory based analysis consistently indicated that Korean sources were important for gaseous oxidized mercury (GOM whereas, for total gaseous mercury (TGM and particulate bound mercury (PBM, long-range and regional transport were also important. A trajectory cluster based approach considering both Hg concentration and the fraction of time each cluster was impacting the site was developed to quantify the effect of Korean sources and out-of-Korean source. This analysis suggests that Korean sources contributed approximately 55 % of the GOM and PBM while there were approximately equal contributions from Korean and out-of-Korean sources for the TGM measured at the site. The ratio of GOM / PBM decreased when the site was impacted by long-range transport, suggesting that this ratio may be a useful tool for identifying the relative significance of local sources vs. long-range transport. The secondary formation of PBM through gas-particle partitioning with GOM was found to be important at low temperatures and high relative humidity.

  6. Enhanced nitrogen removal in a wastewater treatment process characterized by carbon source manipulation with biological adsorption and sludge hydrolysis.

    Science.gov (United States)

    Liu, Hongbo; Zhao, Fang; Mao, Boyang; Wen, Xianghua

    2012-06-01

    An innovative adsorption/nitrification/denitrification/sludge-hydrolysis wastewater treatment process (ENRS) characterized by carbon source manipulation with a biological adsorption unit and a sludge hydrolysis unit was developed to enhance nitrogen removal and reduce sludge production for municipal wastewater treatment. The system presented good performance in pollutants removal, yielding the effluent with average COD, NH(4)(+)-N, TN and TP of 48.5, 0.6, 13.2 and 1.0 mg/L, respectively. Sixty percent of the total carbon source in the influent was concentrated and separated by the quick adsorption of activated sludge, providing the possibilities of reusing waste carbon source in the denitrification tank and accumulating nitrobacteria in the nitrification tank. Low temperature of 6-15 °C and high hydraulic loading rate of 3.0-15.0 m(3)/d did not affect NH(4)(+)-N removal performance, yielding the NH(4)(+)-N of lower 1.0 mg/L in the effluent. Furthermore, 50% of the residual sludge in the ENRS system could be transformed into soluble COD (SCOD) by alkaline thermal hydrolysis with temperature of 60 °C and pH of 11, and the hydrolyzed carbon could completely substitute methanol as a good quality carbon to support high efficient denitrification.

  7. Characteristics of High Time-Resolved Concentrations of Particulate Inorganic Ions and Black Carbon Downwind of Seoul, Korea

    Science.gov (United States)

    Lee, Y.; Choi, Y.; Kim, C.; Ghim, Y.

    2012-12-01

    Concentrations of inorganic ions and black carbon (BC) in PM2.5 were continuously measured using PILS (particle-into-liquid sampler, ADI 2081, Applikon) and MAAP (Multiangle Absorption Photometer, Model 5012, Thermo), respectively, for three and half months from mid-February to May, at intervals of 20-30 minutes. The measurements were made at the Global Campus of Hankuk University of Foreign Studies, about 35 km southeast of downtown Seoul, the general area of which is affected by prevailing northwesterlies. The site is considered to be an ideal place for exploring transport of air pollutants and formation of secondary ions by photochemical reactions since there are no major emission sources nearby except a 4-lane road running about 1.4 km to the west. Analyses were made by two stages. In the first stage, typical types of diurnal variations in inorganic ions and BC concentrations were identified using cluster analysis. Diurnal variations in concentrations of each cluster were compared with the mean diurnal variations during the measurement period. Factors causing the differences in diurnal variations were discussed by cluster and by species. In the second stage, high and low concentration episodes were determined based on three-day moving averages of the sum of concentrations of particulate inorganic ions and BC. Mean concentrations and compositions in each episode were compared with those during the measurement period.

  8. Investigation of the spatiotemporal variation and influencing factors on fine particulate matter and carbon monoxide concentrations near a road intersection

    Science.gov (United States)

    Wang, Zhanyong; Lu, Qing-Chang; He, Hong-Di; Wang, Dongsheng; Gao, Ya; Peng, Zhong-Ren

    2016-05-01

    The minute-scale variations of fine particulate matter (PM2.5) and carbon monoxide (CO) concentrations near a road intersection in Shanghai, China were investigated to identify the influencing factors at three traffic periods. Measurement results demonstrate a synchronous variation of pollutant concentrations at the roadside and setbacks, and the average concentration of PM2.5 at the roadside is 7% (44% for CO) higher than that of setbacks within 500 m of the intersection. The pollution level at traffic peak periods is found to be higher than that of off-peak periods, and the morning peak period is found to be the most polluted due to a large amount of diesel vehicles and unfavorable dispersion conditions. Partial least square regressions were constructed for influencing factors and setback pollutant concentrations, and results indicate that meteorological factors are the most significant, followed by setback distance from the intersection and traffic factors. CO is found to be sensitive to distance from the traffic source and vehicle type, and highly dependent on local traffic conditions, whereas PM2.5 originates more from other sources and background levels. These findings demonstrate the importance of localized factors in understanding spatiotemporal patterns of air pollution at intersections, and support decision makers in roadside pollution management and control.

  9. [Testing of Concentration and Characteristics of Particulate Matters Emitted from Stationary Combustion Sources in Beijing].

    Science.gov (United States)

    Hu, Yue-qi; Wu, Xiao-dong; Wang, Chen; Liang, Yun-ping; Ma, Zhao-hui

    2016-05-15

    A self-built monitoring sampling system on particulate matters and water soluble ions emitted from stationary combustion sources and a size separated sampling system on particulate matters based on FPS4000 and ELPI + were applied to test particulate matters in fumes of typical stationary combustion sources in Beijing. The results showed that the maximum concentration of total particulate matters in fumes of stationary combustion sources in Beijing was 83.68 mg · m⁻³ in standard smoke oxygen content and the minimum was 0.12 mg · m⁻³. And particle number concentration was in the 10⁴-10⁶ cm⁻³ number of grade. Both mass and number concentration ranking order of particulate matters emitted from stationary combustion sources in Beijing was: heating gas fired boilers power plant coal fired boilers coal fired boilers. And two or three peaks existed under 1 µm of particulate size for both number size distribution and mass size distribution. The number concentration for PM₂.₅ accounted for over 99.8% of that for PM₁₀ and that for PM₀.₁ accounted for over 83% of that for PM₂.₅. But the proportions of PM₀.₁, and PM₂.₅ in PM₁₀ were significantly lower in quality analysis,the proportion of PM₂.₅ in PM₁₀ was about 82%, and that of PM₀.₁ in PM₂.₅ was about 27%-33%. PMID:27506016

  10. CONTRIBUTION OF RADON FLOWS AND RADON SOURCES TO THE RADON CONCENTRATION IN A DWELLING

    NARCIS (Netherlands)

    DEMEIJER, RJ; STOOP, P; PUT, LW

    1992-01-01

    In this paper a model is presented for analysis of the radon concentrations in a compartment in terms of contributions from transport by flows of air between compartments and from radon sources in the compartment. Measurements were made to study the effect of increased natural ventilation of the cra

  11. Dissolved black carbon in Antarctic lakes: Chemical signatures of past and present sources

    Science.gov (United States)

    Khan, Alia L.; Jaffé, Rudolf; Ding, Yan; McKnight, Diane M.

    2016-06-01

    The perennially ice-covered, closed-basin lakes in the McMurdo Dry Valleys, Antarctica, serve as sentinels for understanding the fate of dissolved black carbon from glacial sources in aquatic ecosystems. Here we show that dissolved black carbon can persist in freshwater and saline surface waters for thousands of years, while preserving the chemical signature of the original source materials. The ancient brines of the lake bottom waters have retained dissolved black carbon with a woody chemical signature, representing long-range transport of black carbon from wildfires. In contrast, the surface waters are enriched in contemporary black carbon from fossil fuel combustion. Comparison of samples collected 25 years apart from the same lake suggests that the enrichment in anthropogenic black carbon is recent. Differences in the chemical composition of dissolved black carbon among the lakes are likely due to biogeochemical processing such as photochemical degradation and sorption on metal oxides.

  12. Application of central composite design to optimize the amount of carbon source and prebiotics for Bifidobacterium bifidum BB01

    Directory of Open Access Journals (Sweden)

    Shu Guowei

    2016-06-01

    Full Text Available The objective of the present study was to obtain the optimum proportion of the carbon source and prebiotics for Bifidobacterium bifidum BB01 by the central composite design (CCD. The effect of carbon source (lactose and two prebiotics (inulin and fructooligosaccharides on the BB01 were observed by measuring the OD600 value, pH value and the viable counts at 18h. The final optimized concentrations of carbon source and prebiotics were: lactose 1.6%, inulin 0.26%, and fructooligosaccharides 0.22%. The result indicates that the growth of B. bifidum BB01 shows an significant increase in the optimized culture medium (p < 0.05, the OD600 value reached 1.434 at 18h, which increased 6.58% compared to the control. And the viable counts of B. bifidum BB01 increased 24.36% and reached (2.17±0.06 ×109cfu/mL. The results show that the optimization of the carbon source and prebiotics using CCD in this study is workable and necessary.

  13. Wetlands as a large carbon source for inland waters

    Science.gov (United States)

    Abril, Gwenaël; Martinez, Jean-Michel; Artigas, L. Felipe; Moreira-Turcq, Patricia; Benedetti, Marc F.; Vidal, Luciana; Meziane, Tarik; Kim, Jung-Hyun; Bernardes, Marcelo C.; Deborde, Jonathan; Lima Souza, Edivaldo; Albéric, Patrick; Landim de Souza, Marcelo F.; Roland, Fabio

    2014-05-01

    Recent estimates suggests that up to 3 PgC y-1 could be emitted as CO2 from global inland waters, offsetting the carbon uptake by terrestrial ecosystems. It is generally assumed that inland waters emit carbon previously fixed upstream by land plant photosynthesis and subsequently transported downstream with runoff. But the observed carbon fluxes from first-order streams do not account for all of the CO2 outgassing at the scale of entire watersheds. Three-quarters of the world's flooded land are temporary wetlands. However, the contribution of these productive ecosystems to the inland water carbon budget has been largely overlooked. Based on observations in rivers and floodplains of the central Amazon, we suggest that wetlands pump large amounts of atmospheric CO2 into river waters. Indeed, the magnitude of CO2 outgassing in Amazonian waters is spatially and temporally related to their connection with the semi-aquatic vegetation that performs aerial photosynthesis (Flooded forests and floating macrophytes). These wetlands export half of their gross primary production to waters as dissolved CO2 and organic carbon, compared to only a few percent of gross primary production in upland ecosystems. Global carbon budgets should explicitly address temporary or vegetated flooded areas, as these ecosystems combine high aerial primary production with a large and fast carbon export capacity, potentially supporting a significant fraction of CO2 evasion from inland waters.

  14. Sources and Dynamics of Inorganic Carbon within the Upper Reaches of the Xi River Basin, Southwest China

    Science.gov (United States)

    Zou, Junyu

    2016-01-01

    The carbon isotopic composition (δ13C) of dissolved and particulate inorganic carbon (DIC; PIC) was used to compare and analyze the origin, dynamics and evolution of inorganic carbon in two headwater tributaries of the Xi River, Southwest China. Carbonate dissolution and soil CO2 were regarded as the primary sources of DIC on the basis of δ13CDIC values which varied along the Nanpan and Beipan Rivers, from −13.9‰ to 8.1‰. Spatial trends in DIC differed between the two rivers (i.e., the tributaries), in part because factors controlling pCO2, which strongly affected carbonate dissolution, differed between the two river basins. Transport of soil CO2 and organic carbon through hydrologic conduits predominately controlled the levels of pCO2 in the Nanpan River. However, pCO2 along the upper reaches of the Nanpan River also was controlled by the extent of urbanization and industrialization relative to agriculture. DIC concentrations in the highly urbanized upper reaches of the Nanpan River were typical higher than in other carbonate-dominated areas of the upper Xi River. Within the Beipan River, the oxidation of organic carbon is the primary process that maintains pCO2 levels. The pCO2 within the Beipan River was more affected by sulfuric acid from coal industries, inputs from a scenic spot, and groundwater than along the Nanpan River. With regards to PIC, the contents and δ13C values in the Nanpan River were generally lower than those in the Beipan River, indicating that chemical and physical weathering contributes more marine carbonate detritus to the PIC along the Beipan River. The CO2 evasion flux from the Nanpan River was higher than that in the Beipan River, and generally higher than along the middle and lower reaches of the Xi River, demonstrating that the Nanpan River is an important net source of atmospheric CO2 in Southwest China. PMID:27513939

  15. Point source pollution and variability of nitrate concentrations in water from shallow aquifers

    Science.gov (United States)

    Nemčić-Jurec, Jasna; Jazbec, Anamarija

    2016-01-01

    Agriculture is one of the several major sources of nitrate pollution, and therefore the EU Nitrate Directive, designed to decrease pollution, has been implemented. Point sources like septic systems and broken sewage systems also contribute to water pollution. Pollution of groundwater by nitrate from 19 shallow wells was studied in a typical agricultural region, middle Podravina, in northwest Croatia. The concentration of nitrate ranged from R6, there was no statistically significant difference in nitrate concentrations (F = 1.98; p = 0.15) during the years 2002-2007. Average concentrations of nitrate in all 19 wells for all the analyzed years were between recommended limit value of 25 mg/l (RLV) and MAV except in 2002 (concentration was under RLV). The results of the repeated measures ANOVA showed statistically significant differences between the wells at the point source distance (proximity) of 20 m (F = 10.6; p < 0.001). Average annual concentrations of nitrate during the years studied are not statistically different, but interaction between proximity and years is statistically significant (F = 2.07; p = 0.04). Results of k-means clustering confirmed division into four clusters according to the pollution. Principal component analysis showed that there is only one significant factor, proximity, which explains 91.6 % of the total variability of nitrate. Differences in water quality were found as a result of different environmental factors. These results will contribute to the implementation of the Nitrate Directive in Croatia and the EU.

  16. Acute toxicity when concentration varies with time: A case study with carbon monoxide inhalation by rats.

    Science.gov (United States)

    Sweeney, Lisa M; Sommerville, Douglas R; Goodwin, Michelle R; James, R Arden; Channel, Stephen R

    2016-10-01

    Exposure to time-varying concentrations of toxic compounds is the norm in both occupational settings and daily human life, but little has been done to investigate the impact of variations in concentration on toxic outcomes; this case study with carbon monoxide helps fill that gap. Median acute lethality of 10-, 20-, 40-, and 60-min continuous exposures of rats to carbon monoxide was well described by the toxic load model (k = C(n) × t; k is constant, C = test concentration, n = toxic load exponent, and t = exposure duration) with n = 1.74. Dose response-relationships for 1-h exposures including a recovery period between 10- or 20-min pulses showed greater similarity (in both median lethality and steepness of dose-response curve) to continuous exposures with equivalent pulse duration and concentration, rather than a 60-min exposure with equivalent time-weighted average concentrations or toxic load. When pulses were of unequal concentration (3:1 ratio), only the high concentration pulse contributed to lethality. These findings show that fluctuations or interruptions in exposure over a short time scale (60 min or less) can have a substantial impact on outcomes (when n > 1), and thus high-resolution monitoring data are needed to aid interpretation of resulting outcomes.

  17. Deriving realistic source boundary conditions for a CFD simulation of concentrations in workroom air.

    Science.gov (United States)

    Feigley, Charles E; Do, Thanh H; Khan, Jamil; Lee, Emily; Schnaufer, Nicholas D; Salzberg, Deborah C

    2011-05-01

    Computational fluid dynamics (CFD) is used increasingly to simulate the distribution of airborne contaminants in enclosed spaces for exposure assessment and control, but the importance of realistic boundary conditions is often not fully appreciated. In a workroom for manufacturing capacitors, full-shift samples for isoamyl acetate (IAA) were collected for 3 days at 16 locations, and velocities were measured at supply grills and at various points near the source. Then, velocity and concentration fields were simulated by 3-dimensional steady-state CFD using 295K tetrahedral cells, the k-ε turbulence model, standard wall function, and convergence criteria of 10(-6) for all scalars. Here, we demonstrate the need to represent boundary conditions accurately, especially emission characteristics at the contaminant source, and to obtain good agreement between observations and CFD results. Emission rates for each day were determined from six concentrations measured in the near field and one upwind using an IAA mass balance. The emission was initially represented as undiluted IAA vapor, but the concentrations estimated using CFD differed greatly from the measured concentrations. A second set of simulations was performed using the same IAA emission rates but a more realistic representation of the source. This yielded good agreement with measured values. Paying particular attention to the region with highest worker exposure potential-within 1.3 m of the source center-the air speed and IAA concentrations estimated by CFD were not significantly different from the measured values (P = 0.92 and P = 0.67, respectively). Thus, careful consideration of source boundary conditions greatly improved agreement with the measured values. PMID:21422277

  18. Thermoascus aurantiacus CBHI/Cel7A Production in Trichoderma reesei on Alternative Carbon Sources

    Science.gov (United States)

    Benkő, Zsuzsa; Drahos, Eszter; Szengyel, Zsolt; Puranen, Terhi; Vehmaanperä, Jari; Réczey, Kati

    To develop functional enzymes in cellulose hydrolysis at or above 70°C the cellobiohydrolase (CBHI/Cel7A) of Thermoascus aurantiacus was cloned and expressed in Trichoderma reesei Rut-C30 under the strong cbh1 promoter. Cellulase production of the parental strain and the novel strain (RF6026) was examined in submerged fermentation experiments using various carbon sources, which were lactose, Solka Floc 200 cellulose powder, and steam pretreated corn stover. An industrially feasible production medium was used containing only distiller's spent grain, KH2PO4, and (NH4)2SO4. Enzyme production was followed by measurements of protein concentration, total cellulase enzyme activity (filter paper activity), β-glucosidase activity, CBHI activity, and endogenase I (EGI) activity. The Thermoascus CBHI/Cel7A activity was taken as an indication of the heterologous gene expression under the cbh1 promoter.

  19. Production of Polyhydroxybutyrate by Bacillus axaraqunsis BIPC01 using Petrochemical Wastewater as Carbon Source

    Directory of Open Access Journals (Sweden)

    Nasim Mayeli

    2015-08-01

    Full Text Available The aim of this study was to use petrochemical wastewater as the source of carbon for the production of polyhydroxyalkanoates (PHA in an effort to decrease its cost of production. For this purpose, PHA producing bacteria were isolated from the petrochemical wastewater of Bandar Imam, Iran. The purified colonies were screened for PHA by Sudan Black B and Nile Blue A staining. Among positively stained bacteria, the best PHA producer was selected on the basis of cell growth, PHA content and the monomer composition of PHA. The phenotypic and genotypic identification this isolate showed it to be Bacillus axaraqunsis. The PHA was produced at a cell density of about 9.46 g/l of maximum concentration of 6.33g/l l, corresponding to 66% of cell dry weight. These results showed that B. axaraqunsis BIPC01 could be a potent PHA producer using wastewater for industrial purpose and simultaneously reducing the environmental pollution.

  20. Production of Feruloyl Esterase from Aspergillus niger by Solid-State Fermentation on Different Carbon Sources

    Directory of Open Access Journals (Sweden)

    Shiyi Ou

    2011-01-01

    Full Text Available A mixture of wheat bran with maize bran as a carbon source and addition of (NH4SO4 as nitrogen source was found to significantly increase production of feruloyl esterase (FAE enzyme compared with wheat bran as a sole carbon and nitrogen source. The optimal conditions in conical flasks were carbon source (30 g to water 1 : 1, maize bran to wheat bran 1 : 2, (NH4SO4 1.2 g and MgSO4 70 mg. Under these conditions, FAE activity was 7.68 mU/g. The FAE activity on the mixed carbon sources showed, high activity against the plant cell walls contained in the cultures.

  1. Source apportionment of elevated BaP concentrations in PM10 aerosols in an alpine valley in Austria

    Science.gov (United States)

    Bauer, Heidi; Puxbaum, Hans; Jankowski, Nicole; Sampaio Cordeiro Wagner, Lylian

    2010-05-01

    INTRODUCTION: In a village situated at 1215 m a.s.l. in a natural preserve in an Austrian alpine valley elevated BaP concentrations have been measured in the last years. A highly frequented highway leading from Italy to Germany passes near the village. Monthly means of particulate BaP concentrations show a clear seasonal trend with values below 1 ng/m³ during the warmer months and with concentrations up to 9 ng/m³ in the cold season. Annual averages in the years 2000 - 2005 ranged between 1.4 and 2.8 ng/m³ - much higher than the EU target value of 1 ng/m³. We used a macrotracer model developed at the Vienna University of Technology to determine the contributions of the sources for BaP emissions, which were mainly space heating with wood and traffic from the highway. EXPERIMENTAL: The macrotracer concept is a nine component model to derive source contribution and explains 80-100% of PM10 aerosols in Austria. The amount of traffic exhaust is derived by using EC as tracer, whereas EC produced by wood burning is subtracted, the amount of wood smoke is derived by the anhydro-sugar levoglucosan and the ratio between the anhydro-sugars levoglucosan and mannosan. For the source apportionment of BaP the applied factors reflect on the one hand the composition of the automotive fleet in Austria and on the other hand the composition of the fire wood in the region. Filter samples collected with a high volume sampler in winter were analyzed for PM10 aerosol mass, total, organic, elemental and carbonate carbon, HULIS, anhydro-sugars, polyols and ions (major ions and organic acids) and PAHs. In the same way emission samples taken at a motor test stand and at a test stand for wood combustion were analyzed (Schmidl et al. 2008). The saccharides were determined using high pH anion exchange and pulsed amperometry (HPAE-PAD). Details of the analytical method are given in Iinuma et al., 2009. Elemental and organic carbon were determined with a thermal-optical instrument (Sunset lab

  2. Organic carbon in Antarctic snow: spatial trends and possible sources

    Digital Repository Service at National Institute of Oceanography (India)

    Antony, R.; Mahalinganathan, K.; Thamban, M.; Nair, S.

    ) screw-capped glass bottles under a laminar-flow benchhousedinaC015C176Ccoldroomprocessingfacility.Carewas taken to ensure that the bottles were filled leaving no head space and were tightly sealed in order to minimize contamination from the atmosphere... addressing issues concerning global carbon dynamics. 6,7 Additionally, it has been shown that organic carbon in snow undergoes photochemical reactions, releasing reactive gas-phase species to the overlying atmosphere. 8C010 DespiteitsimportanceinairC0...

  3. Indoor concentrations of radon 222 and its daughters: sources, range, and environmental influences

    International Nuclear Information System (INIS)

    The author here reviews what is presently known about factors affecting indoor concentrations of radon 222 and its daughters. In US single-family homes, radon concentrations are found to average about 1.5 pCi/1, but substantially higher concentrations occur frequently: perhaps a million US homes have concentrations exceeding 8 pCi/1 (from which occupants receive radiation doses comparable to those now experienced by uranium miners). The major contributor to indoor radon is ordinary soil underlying homes, with this radon being transported indoors primarily by the slight depressurization that occurs toward the bottom of a house interior (due to indoor-outdoor temperature differences and winds). Water from underground sources contributes significantly in a minority of cases, primarily residences with private wells, with public water supplies contributing only a few percent of indoor radon, even when drawn from wells. The strong variability in indoor concentrations is associated primarily with variability in the amount of radon entering homes from these various sources, and secondarily with differences in ventilation rates. However, for a given entry rate, the ventilation rate is the key determinant of indoor concentrations. Human doses are also influenced strongly by the chemical behavior of the daughters (i.e., decay products of radon), and considerable progress has been made recently in investigating a major aspect of this behavior, i.e., the manner in which daughters attach to airborne particles, to walls, and - indeed - to the lining of the lung itself, where the key radiation dose occurs

  4. Interannual variability of ammonia concentrations over the United States: sources and implications

    Science.gov (United States)

    Schiferl, Luke D.; Heald, Colette L.; Van Damme, Martin; Clarisse, Lieven; Clerbaux, Cathy; Coheur, Pierre-François; Nowak, John B.; Neuman, J. Andrew; Herndon, Scott C.; Roscioli, Joseph R.; Eilerman, Scott J.

    2016-09-01

    The variability of atmospheric ammonia (NH3), emitted largely from agricultural sources, is an important factor when considering how inorganic fine particulate matter (PM2.5) concentrations and nitrogen cycling are changing over the United States. This study combines new observations of ammonia concentration from the surface, aboard aircraft, and retrieved by satellite to both evaluate the simulation of ammonia in a chemical transport model (GEOS-Chem) and identify which processes control the variability of these concentrations over a 5-year period (2008-2012). We find that the model generally underrepresents the ammonia concentration near large source regions (by 26 % at surface sites) and fails to reproduce the extent of interannual variability observed at the surface during the summer (JJA). Variability in the base simulation surface ammonia concentration is dominated by meteorology (64 %) as compared to reductions in SO2 and NOx emissions imposed by regulation (32 %) over this period. Introduction of year-to-year varying ammonia emissions based on animal population, fertilizer application, and meteorologically driven volatilization does not substantially improve the model comparison with observed ammonia concentrations, and these ammonia emissions changes have little effect on the simulated ammonia concentration variability compared to those caused by the variability of meteorology and acid-precursor emissions. There is also little effect on the PM2.5 concentration due to ammonia emissions variability in the summer when gas-phase changes are favored, but variability in wintertime emissions, as well as in early spring and late fall, will have a larger impact on PM2.5 formation. This work highlights the need for continued improvement in both satellite-based and in situ ammonia measurements to better constrain the magnitude and impacts of spatial and temporal variability in ammonia concentrations.

  5. Effects of carbon sources and strength of MS medium on germination of somatic embryos of oil palm (Elaeis quineensis Jacq.

    Directory of Open Access Journals (Sweden)

    Aslan Hilae

    2005-12-01

    Full Text Available Various sources of carbon and strengths of Murashige and Skoog (MS medium were investigated for their effect on oil palm somatic embryo germination or induction of shoots and roots from haustoriumstaged embryos. It was found that the highest percentage of shoot formation was obtained in 0.2 M sorbitol containing basal MS medium. A high concentration of alcohol sugar and reduced strength of MS medium enhanced root formation. A high concentration of sucrose or sorbitol also promoted root formation. Percentage of root formation was the highest (31.25% when excised shoots were cultured on root induction medium supplemented with 0.2 M sucrose.

  6. PM10 mass concentration, chemical composition, and sources in the typical coal-dominated industrial city of Pingdingshan, China.

    Science.gov (United States)

    Song, Xiaoyan; Yang, Shushen; Shao, Longyi; Fan, Jingsen; Liu, Yanfei

    2016-11-15

    The atmospheric pollution created by coal-dominated industrial cities in China cannot be neglected. This study focuses on the atmospheric PM10 in the typical industrial city of Pingdingshan City in North China. A total of 44 PM10 samples were collected from three different sites (power plant, mining area, and roadside) in Pingdingshan City during the winter of 2013, and were analyzed gravimetrically and chemically. The Pingdingshan PM10 samples were composed of mineral matter (average of 118.0±58.6μg/m(3), 20.6% of the total PM10 concentration), secondary crystalline particles (338.7±122.0μg/m(3), 59.2%), organic matter (77.3±48.5μg/m(3), 13.5%), and elemental carbon (38.0±28.3μg/m(3), 6.6%). Different sources had different proportions of these components in PM10. The power plant pollutant source was characterized by secondary crystalline particles (377.1μg/m(3)), elemental carbon (51.5μg/m(3)), and organic matter (90.6μg/m(3)) due to coal combustion. The mining area pollutant source was characterized by mineral matter (124.0μg/m(3)) due to weathering of waste dumps. The roadside pollutant source was characterized by mineral matter (130.0μg/m(3)) and organic matter (81.0μg/m(3)) due to road dust and vehicle exhaust, respectively. A positive matrix factorization (PMF) analysis was performed for PM10 source apportionment to identify major anthropogenic sources of PM10 in Pingdingshan. Six factors-crustal matter, coal combustion, vehicle exhaust and abrasion, local burning, weathering of waste dumps, and industrial metal smelting-were identified and their contributions to Pingdingshan PM10 were 19.0%, 31.6%, 7.4%, 6.3%, 9.8%, and 25.9%, respectively. Compared to other major cities in China, the source of PM10 in Pingdingshan was characterized by coal combustion, weathering of waste dumps, and industrial metal smelting. PMID:27450962

  7. Influence of different carbon sources on exopolysaccharide production by Lactobacillus delbrueckii subsp. bulgaricus (B3, G12 and Streptococcus thermophilus (W22

    Directory of Open Access Journals (Sweden)

    Zehra Nur Yuksekdag

    2008-06-01

    Full Text Available Exopolysaccharides (EPSs production was studied by Lactobacillus delbrueckii subsp. bulgaricus (B3, G12 and Streptococcus thermophilus (W22 in the medium containing various carbon sources (glucose, fructose, sucrose or lactose. For all the strains, glucose was the most efficient carbon source and B3, G12 and W22 strains produced 211, 175 and 120 EPS mg/L respectively. Also, the influence of different concentrations of glucose (5,10,15,20,25,30 g/L on EPS production and growth was studied. The results indicated that EPS production and growth were stimulated by the high glucose concentration (30 g/L.

  8. Seasonal odor, ammonia, hydrogen sulfide, and carbon dioxide concentrations and emissions from swine grower-finisher rooms.

    Science.gov (United States)

    Sun, Gang; Guo, Huiqing; Peterson, Jonathan

    2010-04-01

    Seasonal odor and gas (ammonia [NH3], hydrogen sulfide [H2S], and carbon dioxide [CO2]) concentrations and emission rates (OGCERs) from swine facilities are vital for providing accurate source emissions and reducing the uncertainty of setback distances on the basis of emission data. In this study, a repeated measurement experimental method and a split-block statistical model were used to obtain seasonal OGCER profiles from two types of swine grower-finisher rooms in Saskatchewan, Canada, over a 12-month period. The results indicate that the OGCERs were significantly affected by the sampling month and ambient temperature (P dispersion models to reduce uncertainties in setback calculations. It was also found that the seasonal OGCERs from the rooms with fully slatted floors were 6.3-40.6% higher than those with partially slatted floors. The seasonal OGCERs (except for the NH3 concentrations in October, November, and January; the CO2 concentrations in August; and the CO2 emission rates in December) between these two rooms for each measuring month did not differ significantly (P > 0.05). The measured gas concentrations were generally below the permissible exposure limits (PELs) established by the Occupational Safety and Health Administration (OSHA) throughout the year except for the NH3 concentrations in cold weather (December, January, and February).

  9. An inversion algorithm for determining area-source emissions from downwind concentration measurements.

    Science.gov (United States)

    Lehning, M; Shonnard, D R; Chang, D P; Bell, R L

    1994-10-01

    Measuring emissions from nonuniform area sources, such as waste repository sites, has been a difficult problem. A simple but reliable method is not available. An objective method of inverting downwind concentration measurements, utilizing an assumed form of atmospheric dispersion to reconstruct total emission rate and distribution, is described in this study. The Gaussian dispersion model is compared to a more realistic model based on K-theory and similarity expressions. A sensitivity analysis is presented indicating the atmospheric conditions under which a successful application of the method could be anticipated. Field releases of sulfur hexafluoride (SF6) from a simulated area source in flat terrain were conducted to check the method, ability to reconstruct source distribution, and total emission rate. The sensitivity analysis and the field study confirm that a few ground-level concentration measurements and a simple determination of the atmospheric dispersion characteristics are sufficient, under neutral to stable conditions, to obtain the total emission rate accurately. Reconstruction of the spatial pattern of the source is possible by utilizing concentration information from samplers located on two separate ground-level receptor lines, if a shift in the wind direction occurs and if it can be assumed that the total emission rate is time invariant. A method of cross-checking the accuracy of the reconstruction, using a simultaneous tracer release, is presented. PMID:7812684

  10. Optimal Medium Composition to Enhance Poly-β-hydroxybutyrate Production by Ralstonia eutropha Using Cane Molasses as Sole Carbon Source

    Directory of Open Access Journals (Sweden)

    Ali Bozorg

    2015-06-01

    Full Text Available In order to reduce the costs associated with Poly-β-hydroxybutyrate production, growth and Poly-β-hydroxybutyrate production of Ralstonia eutropha were studied in batch culture on different carbon sources. Experiments were designed and conducted to not only lower the cost of Poly-β-hydroxybutyrate production by using inexpensive substrates, but also to increase Poly-β-hydroxybutyrate production by optimizing the culture medium composition. Low cost, abundant carbon sources, including cane molasses, beet molasses, soya bean, and corn steep liquor were used to investigate the possibility of Poly-β-hydroxybutyrate production in such renewable carbon sources. Based on the experimental results, cane molasses with production of 0.49 g/L Poly-β-hydroxybutyrate was selected as the most efficient carbon source. To improve bacterial growth and Poly-β-hydroxybutyrate production, different chemicals were then used to pretreat the cane molasses. Sulfuric acid, with 33% enhancement in Poly-β-hydroxybutyrate production, revealed the highest efficiency in removing heavy metals and suspended impurities and was used to pretreat cane molasses in the subsequent experiments. Additionally, to make the process even more efficient and ultimately more effective, urea and corn steep liquor were used as nitrogen/minerals and vitamin sources, respectively. Using the Response Surface Methodology and through a 2n factorial Central Composite Design, the medium composition was then optimized, and maximum biomass concentration of 5.03 g/L and Poly-β-hydroxybutyrate concentration of 1.63 g/L were obtained.

  11. Potential source identification for aerosol concentrations over a site in Northwestern India

    Science.gov (United States)

    Payra, Swagata; Kumar, Pramod; Verma, Sunita; Prakash, Divya; Soni, Manish

    2016-03-01

    The collocated measurements of aerosols size distribution (ASD) and aerosol optical thickness (AOT) are analyzed simultaneously using Grimm aerosol spectrometer and MICROTOP II Sunphotometer over Jaipur, capital of Rajasthan in India. The contrast temperature characteristics during winter and summer seasons of year 2011 are investigated in the present study. The total aerosol number concentration (TANC, 0.3-20 μm) during winter season was observed higher than in summer time and it was dominated by fine aerosol number concentration (FANC work, Potential Source Contribution Function (PSCF) analysis is applied to identify locations of sources that influenced concentrations of aerosols over study area in two different seasons. PSCF analysis shows that the dust particles from Thar Desert contribute significantly to the coarse aerosol number concentration (CANC). Higher values of the PSCF in north from Jaipur showed the industrial areas in northern India to be the likely sources of fine particles. The variation in size distribution of aerosols during two seasons is clearly reflected in the log normal size distribution curves. The log normal size distribution curves reveals that the particle size less than 0.8 μm is the key contributor in winter for higher ANC.

  12. Urban background levels of particle number concentration and sources in Vilnius, Lithuania

    Science.gov (United States)

    Byčenkienė, Steigvilė; Plauškaitė, Kristina; Dudoitis, Vadimas; Ulevicius, Vidmantas

    2014-06-01

    This study presents results of research on urban aerosol particles with a focus on the aerosol particle number concentration (PNC) and the particle size distribution. The real time measurements of aerosol PNC (> 4.5 nm) and number size distributions (9-840 nm) were performed. The seasonal variations essentially comprised the minimum monthly mean in October 2010 (3400 ± 3000 cm- 3) and the maximum in April 2011 (19,000 ± 15,000 cm- 3). The mean annual PNC was 10,000 ± 8000 cm- 3 with an average mode size of 30-50 nm. The presence of strong diurnal patterns in aerosol PNC was evident as a direct effect of three sources of aerosol particles (nucleation, traffic, and residential heating). Hybrid receptor modeling potential source contribution function (PSCF) and concentration weighted trajectory (CWT) were used by incorporating 72-h backward trajectories and measurements of PNC in Vilnius. The results of trajectory clustering and the PSCF method demonstrated that possible additional source areas contributing to the elevated particle number concentration in Vilnius could be industrial areas in central Europe. Principal component analysis (PCA) revealed highest loadings for PNC, PM10, NOx, NO, NO2 and SO2 concentrations, indicating combustion processes occurring in vehicle engines and use of sulfur-containing fossil fuels for residential heating.

  13. Radiocarbon-based source apportionment of black carbon (BC) in PM 10 aerosols from residential area of suburban Tokyo

    Science.gov (United States)

    Uchida, Masao; Kumata, Hidetoshi; Koike, Yasuyo; Tsuzuki, Mikio; Uchida, Tatsuya; Fujiwara, Kitao; Shibata, Yasuyuki

    2010-04-01

    The AMS technique was applied to analyse black carbon (BC), total organic carbon (TOC), and previously reported polycyclic aromatic hydrocarbons (PAHs) in PM 10 aerosols from a residential area, suburban Tokyo, to determine natural abundance of radiocarbon ( 14C), an ideal tracer to distinguish fossil fuel ( 14C-free) from modern biomass combustion sources of pyrolytic products. The 14C concentrations in BC, isolated using the CTO-375 method, were 42% and 30% pMC (in terms of percent Modern Carbon: pMC) in summer and winter, respectively. The 14C concentrations in BC were also compared with those of compound-class specific 14C content of PAHs previously reported for the same samples: they were 45% and 33% pMC in summer and winter, respectively. The 14C signals of BC were identical to those of high molecular weight (MW ⩾ 226, 5-6 rings) PAHs. The resemblance between 14C signals of BC and PAHs can be referred as a 'certificate' for the validity of the BC isolation method employed in this study. Also, it suggests that 14C-BC approach can be a surrogate for PAHs specific 14C analyses to monitor seasonal source variation of combustion-derived pyrolytic products. On the other hand, 14C contents of total organic carbon in 2004 were 61% and 42% pMC in summer and winter, respectively. This is likely attributed to higher contribution of plant activity in summer.

  14. Sources and sinks of carbon in boreal ecosystems of interior Alaska: A review

    Directory of Open Access Journals (Sweden)

    Thomas A. Douglas

    2014-12-01

    Full Text Available Abstract Boreal ecosystems store large quantities of carbon but are increasingly vulnerable to carbon loss due to disturbance and climate warming. The boreal region in Alaska and Canada, largely underlain by discontinuous permafrost, presents a challenging landscape for itemizing carbon sources and sinks in soil and vegetation. The roles of fire, forest succession, and the presence (or absence of permafrost on carbon cycle, vegetation, and hydrologic processes have been the focus of multidisciplinary research in boreal ecosystems for the past 20 years. However, projections of a warming future climate, an increase in fire severity and extent, and the potential degradation of permafrost could lead to major landscape and carbon cycle changes over the next 20 to 50 years. To assist land managers in interior Alaska in adapting and managing for potential changes in the carbon cycle we developed this review paper by incorporating an overview of the climate, ecosystem processes, vegetation, and soil regimes. Our objective is to provide a synthesis of the most current carbon storage estimates and measurements to guide policy and land management decisions on how to best manage carbon sources and sinks. We surveyed estimates of aboveground and belowground carbon stocks for interior Alaska boreal ecosystems and summarized methane and carbon dioxide fluxes. These data have been converted into similar units to facilitate comparison across ecosystem compartments. We identify potential changes in the carbon cycle with climate change and human disturbance. A novel research question is how compounding disturbances affect carbon sources and sinks associated with boreal ecosystem processes. Finally, we provide recommendations to address the challenges facing land managers in efforts to manage carbon cycle processes. The results of this study can be used for carbon cycle management in other locations within the boreal biome which encompasses a broad distribution

  15. Cluster analysis of particulate matter (PM10) and black carbon (BC) concentrations

    Science.gov (United States)

    Žibert, Janez; Pražnikar, Jure

    2012-09-01

    The monitoring of air-pollution constituents like particulate matter (PM10) and black carbon (BC) can provide information about air quality and the dynamics of emissions. Air quality depends on natural and anthropogenic sources of emissions as well as the weather conditions. For a one-year period the diurnal concentrations of PM10 and BC in the Port of Koper were analysed by clustering days into similar groups according to the similarity of the BC and PM10 hourly derived day-profiles without any prior assumptions about working and non-working days, weather conditions or hot and cold seasons. The analysis was performed by using k-means clustering with the squared Euclidean distance as the similarity measure. The analysis showed that 10 clusters in the BC case produced 3 clusters with just one member day and 7 clusters that encompasses more than one day with similar BC profiles. Similar results were found in the PM10 case, where one cluster has a single-member day, while 7 clusters contain several member days. The clustering analysis revealed that the clusters with less pronounced bimodal patterns and low hourly and average daily concentrations for both types of measurements include the most days in the one-year analysis. A typical day profile of the BC measurements includes a bimodal pattern with morning and evening peaks, while the PM10 measurements reveal a less pronounced bimodality. There are also clusters with single-peak day-profiles. The BC data in such cases exhibit morning peaks, while the PM10 data consist of noon or afternoon single peaks. Single pronounced peaks can be explained by appropriate cluster wind speed profiles. The analysis also revealed some special day-profiles. The BC cluster with a high midnight peak at 30/04/2010 and the PM10 cluster with the highest observed concentration of PM10 at 01/05/2010 (208.0 μg m-3) coincide with 1 May, which is a national holiday in Slovenia and has very strong tradition of bonfire parties. The clustering of

  16. Carbon source from the toroidal pumped limiter during long discharge operation in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Dufour, E.; Brosset, C.; Lowry, C.; Bucalossi, J.; Chappuis, P.; Corre, Y.; Desgranges, C.; Guirlet, R.; Gunn, J.; Loarer, T.; Mitteau, R.; Monier-Garbet, P.; Pegourie, B.; Reichle, R.; Thomas, P.; Tsitrone, E. [Association EURATOM-CEA, CEA/DSM/DRFC, CEA-Cadarache, 13 - St Paul-lez-Durance (France); Hogan, J. [Oak Ridge National Laboratory, 2 Fusion Energy Division, Oak Ridge, TN (United States); Roubin, P.; Martin, C.; Arnas, C. [CNRS-Universite de Provence, LPIIM, UMR 6633, 13 - Marseille (France)

    2005-07-01

    A better understanding of deuterium retention mechanisms requires the knowledge of carbon sources in Tore-Supra. The main source of carbon in the vacuum vessel during long discharges is the toroidal pumped limiter (TPL). This work is devoted to the experimental characterisation of the carbon source from the TPL surface during long discharges using a visible spectroscopy diagnostic. Moreover, we present an attempt to perform a carbon balance over a typical campaign and we discuss it with regards to the deuterium in-vessel inventory deduced from particle balance and the deuterium content of the deposited layers. The study shows that only a third of the estimated deuterium trapped in the vessel is trapped in the carbon deposits. Thus, in the present state of our knowledge and characterisation of the permanent retention, one has to search for mechanisms other than co-deposition to explain the deuterium retention in Tore Supra. (A.C.)

  17. The effect of cation source and dietary cation-anion difference on rumen ion concentrations in lactating dairy cows.

    Science.gov (United States)

    Catterton, T L; Erdman, R A

    2016-08-01

    Many studies have focused on the influence of dietary cation-anion difference (DCAD) on animal performance but few have examined the effect of DCAD on the rumen ionic environment. The objective of this study was to examine the effects of DCAD, cation source (Na vs. K), and anion source (Cl vs. bicarbonate or carbonate) on rumen environment and fermentation. The study used 5 rumen-fistulated dairy cows and 5 dietary treatments that were applied using a 5×5 Latin square design with 2-wk experimental periods. Treatments consisted of (1) the basal total mixed ration (TMR); (2) the basal TMR plus 340mEq/kg of Na (dry matter basis) using NaCl; (3) the basal TMR plus 340mEq/kg of K using KCl; (4) the basal TMR plus 340mEq/kg of Na using NaHCO3; and (5) the basal TMR plus 340mEq/kg of K using K2CO3. On the last day of each experimental period, rumen samples were collected and pooled from 5 different locations at 0, 1.5, 3, 4.5, 6, 9, and 12h postfeeding for measurement of rumen pH and concentrations of strong ions and volatile fatty acids (VFA). Dietary supplementation of individual strong ions increased the corresponding rumen ion concentration. Rumen Na was decreased by 24mEq/L when K was substituted for Na in the diet, but added dietary Na had no effect on rumen K. Rumen Cl was increased by 10mEq/L in diets supplemented with Cl. Cation source had no effect on rumen pH or total VFA concentration. Increased DCAD increased rumen pH by 0.10 pH units and increased rumen acetate by 4mEq/L but did not increase total VFA. This study demonstrated that rumen ion concentrations can be manipulated by dietary ion concentrations. If production and feed efficiency responses to DCAD and ionophores in the diet are affected by rumen Na and K concentrations, then manipulating dietary Na and K could be used either to enhance or diminish those responses. PMID:27289159

  18. Novel ferulic acid esterases from Bifidobacterium sp. produced on selected synthetic and natural carbon sources

    Directory of Open Access Journals (Sweden)

    Dominik Szwajgier

    2010-09-01

    Full Text Available Background. Ferulic acid esterases (or feruloyl esterases, a common group of hydrolases are very well distributed in the plant kongdom. The fungal feruloyl esterases were very extensively studied whereas probiotic lactic acid bacteria as the source of this enzyme were generally omitted. Free phenolic acids – strong antioxidants can be released from the dietary fiber by the action of intestinal lactic acid bacteria. The aim of this study was to examine the three probiotic Bifidobacterium strains to produce extracellular FAE on different synthetic and natural carbon sources. Material and methods. Studies were carried out using Bifidibacteriumstrains (B. animalis Bi30, B. catenulatum KD 14 and B. longum KN 29. The strains were cultivated using minimal growth media containing selected natural and synthetic carbon sources: German wheat bran, rye bran, barley spent grain, isolated larchwood arabinogalactan, apple pectin, corn pectin, methyl esters of phenolic acids. The production of extracellular feruloyl esterase was estimated using the post cultivation supernatants and methyl ferulate. The concentration of ferulic acid released from the ester was determined using HPLC with DAD detection. Results. The most efficient bacterial strain for FAE production was B. animalis cultivated in the presence of methyl p-coumarate and methyl ferulate as the main carbon sources (14.95 nmol·ml-1·min-1 and 4.38 nmol·ml-1·min-1, respectively. In the case of each FAE, the highest activity was obtained at 37oC (pH 6.3 in Theorell/Steinhagen buffer (B. animalis Bi30 or in Tris/HCl buffer (B. catenulatum KD14 and B. longum KN29. Taking under consideration all results, it should be noticed that the highest feruloyl esterase activities were obtained using synthetic methyl esters of phenolic acids. Conclusions. The presented resultsbroaden the knowledgeabout the production of the feruloyl esterase by probiotic bacteria. Although the enzyme is only accessory during

  19. Sub-Surface Carbon Dioxide Concentration Measurement Using a Fiber Based Sensor in a Call/Return Geometry for Carbon Sequestration Site Monitoring

    Science.gov (United States)

    Wicks, G. R.; Soukup, B.; Repasky, K. S.; Carlsten, J.; Barr, J. L.; Dobeck, L.

    2010-12-01

    Geologic carbon sequestration is a means to mitigate the increasing atmospheric concentration of carbon dioxide (CO2) by capturing the CO2 at a source such as a power generation facility and storing the captured CO2 in geologic formations. Many technologic advances will need to occur for successful carbon sequestration including near surface monitoring tools and techniques to ensure site integrity and public safety. Researchers at Montana State University (MSU) are developing a scalable fiber sensor array in a call/return configuration for monitoring near sub-surface CO2 concentrations. The low cost fiber sensor array being developed at MSU for sub-surface CO2 detection for monitoring carbon sequestration sites will utilize a series of fiber probes connected to a two detectors and a 1 x N fiber switch that can direct the light to one of N fiber probes. The fiber sensor array will utilize a single tunable distributed feedback (DFB) diode laser with a center wavelength of 2.004 μm to access CO2 absorption features. The output from the DFB laser is incident on an inline fiber splitter that directs part of the light to a reference detector while the remaining light is directed to a fiber probe where the laser light interacts with the CO2. The light from the fiber probe is directed back through the switch and is incident on a transmission detector. The transmission as a function of wavelength is measured and a CO2 concentration is calculated. The fiber sensor array can easily be reconfigured by simply moving the fiber probes. Low cost is achieved by using inexpensive passive components in the fiber probes while limiting the number of the more expensive components including the DFB laser, the two detectors, and the single fiber switch. The fiber sensor was tested over a thirty day period at the Zero Emission Research Technology (ZERT) facility that was developed for testing surface and near surface carbon sequestration monitoring instrumentation using a controlled

  20. Black Carbon Concentrations and Diesel Vehicle Emission FactorsDerived from Coefficient of Haze Measurements in California:1967-2003

    Energy Technology Data Exchange (ETDEWEB)

    Kirchstetter, Thomas W.; Aguiar, Jeffery; Tonse, Shaheen; Novakov, T.

    2007-10-01

    We have derived ambient black carbon (BC) concentrations and estimated emission factors for on-road diesel vehicles from archived Coefficient of Haze (COH) data that was routinely collected beginning in 1967 at 11 locations in the San Francisco Bay Area. COH values are a measure of the attenuation of light by particles collected on a white filter, and available data indicate they are proportional to BC concentrations measured using the conventional aethalometer. Monthly averaged BC concentrations are up to five times greater in winter than summer, and, consequently, so is the population's exposure to BC. The seasonal cycle in BC concentrations is similar for all Bay Area sites, most likely due to area-wide decreased pollutant dispersion during wintertime. A strong weekly cycle is also evident, with weekend concentrations significantly lower than weekday concentrations, consistent with decreased diesel traffic volume on weekends. The weekly cycle suggests that, in the Bay Area, diesel vehicle emissions are the dominant source of BC aerosol. Despite the continuous increase in diesel fuel consumption in California, annual Bay Area average BC concentrations decreased by a factor of {approx}3 from the late 1960s to the early 2000s. Based on estimated annual BC concentrations, on-road diesel fuel consumption, and recent measurements of on-road diesel vehicle BC emissions, diesel BC emission factors decreased by an order of magnitude over the study period. Reductions in the BC emission factor reflect improved engine technology, emission controls and changes in diesel fuel composition. A new BC monitoring network is needed to continue tracking ambient BC trends because the network of COH monitors has recently been retired.

  1. Black Carbon Concentrations and Diesel Vehicle Emission Factors Derived from Coefficient of Haze Measurements in California: 1967-2003

    Energy Technology Data Exchange (ETDEWEB)

    Tast, CynthiaL; Kirchstetter, Thomas W.; Aguiar, Jeffery; Tonse, Shaheen; Novakov, T.; Fairley, David

    2007-11-09

    We have derived ambient black carbon (BC) concentrations and estimated emission factors for on-road diesel vehicles from archived Coefficient of Haze (COH) data that was routinely collected beginning in 1967 at 11 locations in the San Francisco Bay Area. COH values are a measure of the attenuation of light by particles collected on a white filter, and available data indicate they are proportional to BC concentrations measured using the conventional aethalometer. Monthly averaged BC concentrations are up to five times greater in winter than summer, and, consequently, so is the population?s exposure to BC. The seasonal cycle in BC concentrations is similar for all Bay Area sites, most likely due to area-wide decreased pollutant dispersion during wintertime. A strong weekly cycle is also evident, with weekend concentrations significantly lower than weekday concentrations, consistent with decreased diesel traffic volume on weekends. The weekly cycle suggests that, in the Bay Area, diesel vehicle emissions are the dominant source of BC aerosol. Despite the continuous increase in diesel fuel consumption in California, annual Bay Area average BC concentrations decreased by a factor of ~;;3 from the late 1960s to the early 2000s. Based on estimated annual BC concentrations, on-road diesel fuel consumption, and recent measurements of on-road diesel vehicle BC emissions, diesel BC emission factors decreased by an order of magnitude over the study period. Reductions in the BC emission factor reflect improved engine technology, emission controls and changes in diesel fuel composition. A new BC monitoring network is needed to continue tracking ambient BC trends because the network of COH monitors has recently been retired.

  2. FOOD SOURCES AND CARBON BUDGET OF CHINESE PRAWN PENAEUS CHINENSIS

    Institute of Scientific and Technical Information of China (English)

    董双林; 张硕; 王芳

    2002-01-01

    This study deals with contribution of artificial food pellet and natural food to Chinese prawn (Penaeus orientalis) growth in a semiintensive culture pond. The prawn carbon consumption, budget, and the effects of some factors on the budget were investigated. The results showed that 26.2% of P. orientalis growth carbon came from formulated feed at the initial culture stage (when the prawns were 0.06±0.01 g in wet weight), and was 62.5% when the prawns were 9.56±1.04 g. The remaining part of the growth carbon was derived from organic fertilizer and natural food. The highest growth rate occurred at 20×10-3 salinity. Suitable salinity for culturing Chinese prawn was (20-28)×10-3.

  3. Food sources and carbon dudget of chinese prawn Penaeus chinensis

    Science.gov (United States)

    Dong, Shuang-Lin; Zhang, Shuo; Wang, Fang

    2002-03-01

    This study deals with contribution of artificial food pellet and natural food to Chinese prawn ( Penaeus orientalis) growth in a semi-intensive culture pond. The prawn carbon consumption, budget, and the effects of some factors on the budget were investigated. The results showed that 26.2% of P. orientalis growth carbon came from formulated feed at the initial culture stage (when the prawns were 0.06±0.01 g in wet weight), and was 62.5% when the prawns were 9.56±1.04 g. The remaining part of the growth carbon was derived from organic fertilizer and natural food. The highest growth rate occurred at 20×10-3 salinity. Suitable salinity for culturing Chinese prawn was (20 28)×10-3.

  4. In situ expression of genes involved in carbon concentrating expression of genes involved in carbon concentratingmechanisms in hot spring cyanobacteria

    DEFF Research Database (Denmark)

    Jensen, Sheila Ingemann; Steunou, Anne-Soisig; Bhaya, Devaki;

    supersaturating levels, and the intense photosynthetic activity of the cyanobacteria causes a pH >9.5 in the euphotic zone of the mat. During the night, the mat rapidly becomes anoxic, and intense respiration, reoxidation of reduced solutes and fermentation acidifies the mat to pH ~7.5. High temperature (55-70 0C...... to develop the capacity to accumulate Ci over the course of the day through the induction of genes associated with the carbon concentrating mechanism (CCM). The genomes of two Synechococcus isolates from the mat have revealed the presence of two CO2 hydration systems, two putative HCO3- transporters and a ß...

  5. A source-to-sink perspective on the mobilization, transport, and burial of organic carbon following the 2008 Sichuan earthquake

    Science.gov (United States)

    West, A.; Li, G.; Hammond, D. E.; Jin, Z.

    2012-12-01

    The mobilization and fluvial transport of organic carbon is one of the most important geochemical legacies of landslides triggered by extreme events such as major floods or earthquakes. While there is some information about the quantity of carbon carried by rivers under varying flow regimes, and even in the aftermath of single large events, there is little source-to-sink information about the transfer of this carbon through river systems into depositional centers, and about the geochemical transformations following deposition. These processes may be distinct in the aftermath of extreme events because of the association of organic carbon transport with high clastic sediment loads. In this study, we use the legacy of the 2008 Mw 7.9 Wenchuan Earthquake in Sichuan, China, to explore the mobilization, transport, and ultimate fate of organic carbon associated with co-seismic and post-seismic landslides. We focus on Zipingpu Reservoir, which serves as a trap for material carried by the Min Jiang river that drains the epicentral region most dramatically affected by landslides. We use revised landslide and biomass maps to quantify total organic carbon mobilized from hillslopes within the reservoir catchment area. We have collected sediment cores from the reservoir itself, and together with estimates of sedimentation rates constrained by short-lived radionuclide abundances, we construct a budget for the carbon transport into the reservoir based on analyses of sediment solid phase organic C concentrations and isotope ratios. Post-depositional diagenetic alteration is quantified using pore water profiles, including DIC concentration, carbon isotope compositions, and the isotopic composition of methane collected both in-situ from pore waters, and associated with actively bubbling methane seeps.

  6. Evolution and variation of atmospheric carbon dioxide concentration over terrestrial ecosystems as derived from eddy covariance measurements

    Science.gov (United States)

    Liu, Min; Wu, Jiabing; Zhu, Xudong; He, Honglin; Jia, Wenxiao; Xiang, Weining

    2015-08-01

    Carbon dioxide (CO2) is the most important anthropogenic greenhouse gas contributing to global climate change. Understanding the temporal and spatial variations of CO2 concentration over terrestrial ecosystems provides additional insight into global atmospheric variability of CO2 concentration. Using 355 site-years of CO2 concentration observations at 104 eddy-covariance flux tower sites in Northern Hemisphere, we presented a comprehensive analysis of evolution and variation of atmospheric CO2 concentration over terrestrial ecosystem (ACTE) for the period of 1997-2006. Our results showed that ACTE exhibited a strong seasonal variations, with an average seaonsal amplitude (peak-trough difference) of 14.8 ppm, which was approximately threefold that global mean CO2 observed in Mauna Loa in the United States (MLO). The seasonal variation of CO2 were mostly dominant by terrestrial carbon fluxes, i.e., net ecosystem procution (NEP) and gross primary produciton (GPP), with correlation coefficient(r) were -0.55 and -0.60 for NEP and GPP, respectively. However, the influence of carbon fluxes on CO2 were not significant at interannual scale, which implyed that the inter-annual changing trends of atmospheric CO2 in Northern Hemisphere were likely to depend more on anthropogenic CO2 emissions sources than on ecosystem change. It was estimated, by fitting a harmonic model to monthly-mean ACTE, that both annual mean and seasonal amplitude of ACTE increased over the 10-year period at rates of 2.04 and 0.60 ppm yr-1, respectively. The uptrend of annual ACTE could be attributed to the dramatic global increase of CO2 emissions during the study period, whereas the increasing amplitude could be related to the increases in Northern Hemisphere biospheric activity. This study also found that the annual CO2 concentration showed large variation among ecosystems, with the high value appeared in deciduous broadleaf forest, evergreen broadleaf forest and cropland. We attribute these

  7. Quasi-steady carbon plasma source for neutral beam injector.

    Science.gov (United States)

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2014-02-01

    Carbon plasma is successfully sustained during 1000 s without any carrier gas in the bucket type ionization chamber with cusp magnetic field. Every several seconds, seed plasmas having ∼3 ms duration time are injected into the ionization chamber by a shunting arch plasma gun. The weakly ionized carbon plasma ejected from the shunting arch is also ionized by 2.45 GHz microwave at the electron cyclotron resonance surface and the plasma can be sustained even in the interval of gun discharges. Control of the gun discharge interval allows to keep high pressure and to sustain the plasma for long duration.

  8. Quasi-steady carbon plasma source for neutral beam injector

    International Nuclear Information System (INIS)

    Carbon plasma is successfully sustained during 1000 s without any carrier gas in the bucket type ionization chamber with cusp magnetic field. Every several seconds, seed plasmas having ∼3 ms duration time are injected into the ionization chamber by a shunting arch plasma gun. The weakly ionized carbon plasma ejected from the shunting arch is also ionized by 2.45 GHz microwave at the electron cyclotron resonance surface and the plasma can be sustained even in the interval of gun discharges. Control of the gun discharge interval allows to keep high pressure and to sustain the plasma for long duration

  9. Quasi-steady carbon plasma source for neutral beam injector.

    Science.gov (United States)

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2014-02-01

    Carbon plasma is successfully sustained during 1000 s without any carrier gas in the bucket type ionization chamber with cusp magnetic field. Every several seconds, seed plasmas having ∼3 ms duration time are injected into the ionization chamber by a shunting arch plasma gun. The weakly ionized carbon plasma ejected from the shunting arch is also ionized by 2.45 GHz microwave at the electron cyclotron resonance surface and the plasma can be sustained even in the interval of gun discharges. Control of the gun discharge interval allows to keep high pressure and to sustain the plasma for long duration. PMID:24593646

  10. Colored dissolved organic matter in shallow estuaries: relationships between carbon sources and light attenuation

    Science.gov (United States)

    Oestreich, W.K.; Ganju, Neil Kamal; Pohlman, John; Suttles, Steven

    2016-01-01

    Light availability is of primary importance to the ecological function of shallow estuaries. For example, benthic primary production by submerged aquatic vegetation is contingent upon light penetration to the seabed. A major component that attenuates light in estuaries is colored dissolved organic matter (CDOM). CDOM is often measured via a proxy, fluorescing dissolved organic matter (fDOM), due to the ease of in situ fDOM sensor measurements. Fluorescence must be converted to CDOM absorbance for use in light attenuation calculations. However, this CDOM–fDOM relationship varies among and within estuaries. We quantified the variability in this relationship within three estuaries along the mid-Atlantic margin of the eastern United States: West Falmouth Harbor (MA), Barnegat Bay (NJ), and Chincoteague Bay (MD/VA). Land use surrounding these estuaries ranges from urban to developed, with varying sources of nutrients and organic matter. Measurements of fDOM (excitation and emission wavelengths of 365 nm (±5 nm) and 460 nm (±40 nm), respectively) and CDOM absorbance were taken along a terrestrial-to-marine gradient in all three estuaries. The ratio of the absorption coefficient at 340 nm (m−1) to fDOM (QSU) was higher in West Falmouth Harbor (1.22) than in Barnegat Bay (0.22) and Chincoteague Bay (0.17). The CDOM : fDOM absorption ratio was variable between sites within West Falmouth Harbor and Barnegat Bay, but consistent between sites within Chincoteague Bay. Stable carbon isotope analysis for constraining the source of dissolved organic matter (DOM) in West Falmouth Harbor and Barnegat Bay yielded δ13C values ranging from −19.7 to −26.1 ‰ and −20.8 to −26.7 ‰, respectively. Concentration and stable carbon isotope mixing models of DOC (dissolved organic carbon) indicate a contribution of 13C-enriched DOC in the estuaries. The most likely source of 13C-enriched DOC for the systems we investigated is Spartina cordgrass. Comparison of

  11. Colored dissolved organic matter in shallow estuaries: relationships between carbon sources and light attenuation

    Science.gov (United States)

    Oestreich, W. K.; Ganju, N. K.; Pohlman, J. W.; Suttles, S. E.

    2016-02-01

    Light availability is of primary importance to the ecological function of shallow estuaries. For example, benthic primary production by submerged aquatic vegetation is contingent upon light penetration to the seabed. A major component that attenuates light in estuaries is colored dissolved organic matter (CDOM). CDOM is often measured via a proxy, fluorescing dissolved organic matter (fDOM), due to the ease of in situ fDOM sensor measurements. Fluorescence must be converted to CDOM absorbance for use in light attenuation calculations. However, this CDOM-fDOM relationship varies among and within estuaries. We quantified the variability in this relationship within three estuaries along the mid-Atlantic margin of the eastern United States: West Falmouth Harbor (MA), Barnegat Bay (NJ), and Chincoteague Bay (MD/VA). Land use surrounding these estuaries ranges from urban to developed, with varying sources of nutrients and organic matter. Measurements of fDOM (excitation and emission wavelengths of 365 nm (±5 nm) and 460 nm (±40 nm), respectively) and CDOM absorbance were taken along a terrestrial-to-marine gradient in all three estuaries. The ratio of the absorption coefficient at 340 nm (m-1) to fDOM (QSU) was higher in West Falmouth Harbor (1.22) than in Barnegat Bay (0.22) and Chincoteague Bay (0.17). The CDOM : fDOM absorption ratio was variable between sites within West Falmouth Harbor and Barnegat Bay, but consistent between sites within Chincoteague Bay. Stable carbon isotope analysis for constraining the source of dissolved organic matter (DOM) in West Falmouth Harbor and Barnegat Bay yielded δ13C values ranging from -19.7 to -26.1 ‰ and -20.8 to -26.7 ‰, respectively. Concentration and stable carbon isotope mixing models of DOC (dissolved organic carbon) indicate a contribution of 13C-enriched DOC in the estuaries. The most likely source of 13C-enriched DOC for the systems we investigated is Spartina cordgrass. Comparison of DOC source to CDOM : f

  12. The Effects of Three Mineral Nitrogen Sources and Zinc on Maize and Wheat Straw Decomposition and Soil Organic Carbon

    Institute of Scientific and Technical Information of China (English)

    Ogunniyi Jumoke Esther; GUO Chun-hui; TIAN Xiao-hong; LI Hong-yun; ZHOU Yang-xue

    2014-01-01

    The incorporation of straw in cultivated ifelds can potentially improve soil quality and crop yield. However, the presence of recalcitrant carbon compounds in straw slow its decomposition rate. The objective of this study was to determine the effects of different nitrogen sources, with and without the application of zinc, on straw decomposition and soil quality. Soils were treated with three different nitrogen sources, with and without zinc: urea (CO(NH2)2), ammonium sulfate ((NH4)2SO4), and ammonium chloride (NH4Cl). The combined treatments were as follows:maize (M) and wheat (W) straw incorporated into urea-, ammonium sulfate-, or ammonium chloride-treated soil (U, S, and C, respectively) with and without zinc (Z) (MU, MUZ, WU, WUZ;MS, MSZ, WS, WSZ;MC, MCZ, WC, WCZ, respectively);straw with zinc only (MZ, WZ);straw with untreated soil (MS, WS);and soil-only or control conditions (NT). The experiment consisted of 17 treatments with four replications. Each pot contained 150 g soil and 1.125 g straw, had a moisture content of 80%of the ifeld capacity, and was incubated for 53 days at 25°C. The rates of CO2-C emission, cumulative CO2-C evolution, total CO2 production in the soils of different treatments were measured to infer decomposition rates. The total organic carbon (TOC), labile organic carbon (LOC), and soil microbial biomass in the soils of different treatments were measured to infer soil quality. All results were signiifcantly different (P<0.05) with the exception of the labile organic carbon (LOC). The maize and wheat straw showed different patterns in CO2 evolution rates. For both straw types, Zn had a synergic effect with U, but an antagonistic effect with the other N sources as determined by the total CO2 produced. The MUZ treatment showed the highest decomposition rate and cumulative CO2 concentration (1 120.29 mg/pot), whereas the WACZ treatment had the lowest cumulative CO2 concentration (1 040.57 mg/pot). The addition of NH4Cl resulted in the

  13. Water cycle dynamic increases resilience of vegetation under higher atmospheric carbon dioxide concentration

    Science.gov (United States)

    Lemordant, L. A.; Gentine, P.; Stéfanon, M.; Drobinski, P. J.; Fatichi, S.

    2015-12-01

    Plant stomata couple the energy, water and carbon cycles. Photosynthesis requires stomata to open to take up carbon dioxide. In the process water vapor is released as transpiration. As atmospheric CO2 concentration rises, for the same amount of CO2 uptake, less water vapor is transpired, translating into higher water use efficiency. Reduced water vapor losses will increase soil water storage if the leaf area coverage remains similar. This will in turn alter the surface energy partitioning: more heat will be dissipated as sensible heat flux, resulting in possibly higher surface temperatures. In contrast with this common hypothesis, our study shows that the water saved during the growing season by increased WUE can be mobilized by the vegetation and help reduce the maximum temperature of mid-latitude heat waves. The large scale meteorological conditions of 2003 are the basis of four regional model simulations coupling an atmospheric model to a surface model. We performed two simulations with respectively 2003 (CTL) and 2100 (FUT) atmospheric CO2 applied to both the atmospheric and surface models. A third (RAD) and a fourth (FER) simulations are run with 2100 CO2 concentration applied to respectively the atmospheric model only and the surface model only. RAD investigates the impact of the radiative forcing, and FER the response to vegetation CO2 fertilization. Our results show that the water saved through higher water use efficiency during the growing season enabled by higher atmospheric carbon dioxide concentrations helps the vegetation to cope during severe heat and dryness conditions in the summer of mid-latitude climate. These results demonstrate that consideration of the vegetation carbon cycle is essential to model the seasonal water cycle dynamic and land-atmosphere interactions, and enhance the accuracy of the model outputs especially for extreme events. They also have important implications for the future of agriculture, water resources management, ecosystems

  14. Predicting Effects of Ocean Acidification and Warming on Algae Lacking Carbon Concentrating Mechanisms.

    Directory of Open Access Journals (Sweden)

    Janet E Kübler

    Full Text Available Seaweeds that lack carbon-concentrating mechanisms are potentially inorganic carbon-limited under current air equilibrium conditions. To estimate effects of increased atmospheric carbon dioxide concentration and ocean acidification on photosynthetic rates, we modeled rates of photosynthesis in response to pCO2, temperature, and their interaction under limiting and saturating photon flux densities. We synthesized the available data for photosynthetic responses of red seaweeds lacking carbon-concentrating mechanisms to light and temperature. The model was parameterized with published data and known carbonate system dynamics. The model predicts that direction and magnitude of response to pCO2 and temperature, depend on photon flux density. At sub-saturating light intensities, photosynthetic rates are predicted to be low and respond positively to increasing pCO2, and negatively to increasing temperature. Consequently, pCO2 and temperature are predicted to interact antagonistically to influence photosynthetic rates at low PFD. The model predicts that pCO2 will have a much larger effect than temperature at sub-saturating light intensities. However, photosynthetic rates under low light will not increase proportionately as pCO2 in seawater continues to rise. In the range of light saturation (Ik, both CO2 and temperature have positive effects on photosynthetic rate and correspondingly strong predicted synergistic effects. At saturating light intensities, the response of photosynthetic rates to increasing pCO2 approaches linearity, but the model also predicts increased importance of thermal over pCO2 effects, with effects acting additively. Increasing boundary layer thickness decreased the effect of added pCO2 and, for very thick boundary layers, overwhelmed the effect of temperature on photosynthetic rates. The maximum photosynthetic rates of strictly CO2-using algae are low, so even large percentage increases in rates with climate change will not

  15. Nitrate Removal from Drinking Water with Sodium Citrate as Sole Carbon Source

    Institute of Scientific and Technical Information of China (English)

    YAN Bo; ZHAO Lin; TAN Xin

    2005-01-01

    This paper investigates the effect of using sodium citrate(NaC6H5O6*2H2O)as sole carbon source for nitrate removal from drinking water.With sodium citrate as sole carbon source, batch experiments have been conducted to study the law of denitrification influenced by pH, C/N and temperature. Results show that a denitrification rate reaching 1.32 g NO-3-N /(g Biomass*d) was obtained when pH was at 7.5,C/N at 1.7(atom ratio), and temperature from 20 ℃ to 30 ℃. The results also show that denitrification rate with sodium citrate as carbon source approaches to that with methanol as carbon source.

  16. Equilibrium concentration of radionuclides in cement/groundwater/carbon steel system

    International Nuclear Information System (INIS)

    Equilibrium concentration of major elements in an underground repository with a capacity of 100,000 drums have been simulated using the geochemical computer code (EQMOD). The simulation has been carried out at the conditions of pH 12 to 13.5, and Eh 520 and -520 mV. Solubilities of magnesium and calcium decrease with the increase of pH. The solubility of iron increases with pH at Eh -520 mV of reducing environment, while it almost entirely exists as the precipitate of Fe(OH)3(s) at Eh 520 mV of oxidizing environment. All of cobalt and nickel are predicted to be dissolved in the liquid phase regardless of pH since the solubility limit is greater than the total concentration. In the case of cesium and strontium, all forms of both ions are present in the liquid phase because they have negligible sorption capacity on cement and large solubility under disposal atmosphere. And thus the total concentration determines the equilibrium concentration. Adsorbed amounts of iodide and carbonate are dependent on adsorption capacity and adsorption equilibrium constant. Especially, the calcite turns out to be a solubility-limiting phase on the carbonate system. In order to validate the model, the equilibrium concentrations measured for a number of systems which consist of iron, cement, synthetic groundwater and radionuclides are compared with those predicted by the model. The concentrations between the model and the experiment of nonadsorptive elements - cesium, strontium, cobalt, nickel and iron, are well agreed. It indicates that the assumptions and the thermodynamic data in this work are valid. Using the adsorption equilibrium constant as a free parameter, the experimental data of iodide and carbonate have been fitted to the model. The model is in a good agreement with the experimental data of the iodide system. (author)

  17. Temporal Variations in Concentrations of Ozone, Nitrogen Dioxide, and Carbon Monoxide at Osijek, Croatia

    Directory of Open Access Journals (Sweden)

    Elvira Kovač-Andrić

    2013-01-01

    Full Text Available The purpose of this study was to investigate the ozone, carbon monoxide, and nitrogen dioxide variations and their correlation with meteorological parameters in Osijek (Eastern Croatia during the summer seasons of 2002, 2007, and 2012. The measured data are discussed in relation to the EU guidelines (Directive 2002/3/EC, Directive 2008/50/EC. In order to characterize ambient air with respect to ozone photochemical pollution we calculated three photochemical pollution indicators. These indicators may also be a valid measure for harmful effects on living organisms. The influence of local meteorological parameters on the measured concentrations of ozone, carbon monoxide, and nitrogen dioxide was also investigated. We have attempted to establish correlations between measured pollutant concentrations and meteorological parameters using the technique of multivariate principal component analysis (PCA.

  18. Labile Organic Carbon in Recharge and its Impact on Groundwater Arsenic Concentrations in Bangladesh

    Science.gov (United States)

    Neumann, R. B.; Ashfaque, K. N.; Badruzzaman, A. M.; Ali, M.; Shoemaker, J. K.; Harvey, C. F.

    2009-12-01

    Researchers have puzzled over the origin of dissolved arsenic in the aquifers of the Ganges Delta since widespread arsenic poisoning from groundwater was publicized two decades ago. Previous work has concluded that biological oxidation of organic carbon drives geochemical transformations that mobilize arsenic from sediments; however, the source of the organic carbon that fuels these processes remains controversial. A combined hydrologic and biogeochemical analysis of a typical site in Bangladesh, where constructed ponds and groundwater-irrigated rice fields are the main sources of recharge, shows that only recharge through pond sediments provides the biologically degradable organic carbon that can drive arsenic mobilization. Numerical groundwater simulations as well as chemical and isotopic indicators suggest that contaminated groundwater originates from excavated ponds and that water originating from rice fields is low in arsenic. In fact, rice fields act as an arsenic sink. Irrigation moves arsenic-rich groundwater from the aquifers and deposits it on the rice fields. Most of the deposited arsenic does not return to the aquifers; it is sorbed by the field’s surface soil and bunds, and is swept away in the monsoon floods. The findings indicate that patterns of arsenic contamination in the shallow aquifer are due to recharge-source variation and complex three-dimensional flow.

  19. Facile synthesis of magnetic mesoporous hollow carbon microspheres for rapid capture of low-concentration peptides.

    Science.gov (United States)

    Cheng, Gong; Zhou, Ming-Da; Zheng, Si-Yang

    2014-08-13

    Mesoporous and hollow carbon microspheres embedded with magnetic nanoparticles (denoted as MHM) were prepared via a facile self-sacrificial method for rapid capture of low-abundant peptides from complex biological samples. The morphology, structure, surface property, and magnetism were well-characterized. The hollow magnetic carbon microspheres have a saturation magnetization value of 130.2 emu g(-1) at room temperature and a Brunauer-Emmett-Teller specific surface area of 48.8 m(2) g(-1) with an average pore size of 9.2 nm for the mesoporous carbon shell. The effectiveness of these MHM affinity microspheres for capture of low-concentration peptides was evaluated by standard peptides, complex protein digests, and real biological samples. These multifunctional hollow carbon microspheres can realize rapid capture and convenient separation of low-concentration peptides. They were validated to have better performance than magnetic mesoporous silica and commercial peptide-enrichment products. In addition, they can be easily recycled and present excellent reusability. Therefore, it is expected that this work may provide a promising tool for high-throughput discovery of peptide biomarkers from biological samples for disease diagnosis and other biomedical applications.

  20. Preparation of Palm Oil Based Carbon Nano tubes at Various Ferrocene Concentration

    International Nuclear Information System (INIS)

    In this work, different ferrocene concentration (1.0-10.0 wt %) in bio hydrocarbon palm oil precursor were utilized to investigate its effect on the produced carbon nano tubes (CNT). The palm oil-ferrocene mixture was vaporized at 450 degree Celsius and pyrolyzed at 800 degree Celsius for 30 min time in argon ambient. The CNT were analyzed using field emission scanning electron microscopy (FESEM), micro-Raman spectroscopy and thermal gravimetric analysis (TGA). The analysis confirmed different growth rate, diameter and morphologies of CNT were formed when different ferrocene concentration were used. Raman spectra revealed the presence of G-band and D-band peaks with varying ID/ IG ratio depending on the catalyst concentration used. The 4.0 wt % was considered to be the most optimum concentration to produce bulk amount with better crystallinity CNT production. (author)

  1. Modelling soil organic carbon concentration of mineral soils in arable lands using legacy soil data

    DEFF Research Database (Denmark)

    Suuster, E; Ritz, Christian; Roostalu, H;

    2012-01-01

    -horizon. Three soil properties were used in all of the developed models: soil type, physical clay content (particle size model predicted SOC concentrations with the smallest mean squared error (0.05%2), suggesting that a mixed-model approach......Soil organic carbon (SOC) concentration is an essential factor in biomass production and soil functioning. SOC concentration values are often obtained by prediction but the prediction accuracy depends much on the method used. Currently, there is a lack of evidence in the soil science literature...... as to the advantages and shortcomings of the different commonly used prediction methods. Therefore, we compared and evaluated the merits of the median approach, analysis of covariance, mixed models and random forests in the context of prediction of SOC concentrations of mineral soils under arable management in the A...

  2. Carbon Nanofibers Modified Graphite Felt for High Performance Anode in High Substrate Concentration Microbial Fuel Cells

    Directory of Open Access Journals (Sweden)

    Youliang Shen

    2014-01-01

    Full Text Available Carbon nanofibers modified graphite fibers (CNFs/GF composite electrode was prepared for anode in high substrate concentration microbial fuel cells. Electrochemical tests showed that the CNFs/GF anode generated a peak current density of 2.42 mA cm−2 at a low acetate concentration of 20 mM, which was 54% higher than that from bare GF. Increase of the acetate concentration to 80 mM, in which the peak current density of the CNFs/GF anode greatly increased and was up to 3.57 mA cm−2, was seven times as that of GF anode. Morphology characterization revealed that the biofilms in the CNFs/GF anode were much denser than those in the bare GF. This result revealed that the nanostructure in the anode not only enhanced current generation but also could tolerate high substrate concentration.

  3. Comparative study on bacterial carbon sources in lake sediments: the role of methanotrophy

    NARCIS (Netherlands)

    Steger, K.; Premke, K.; Gudasz, C.; Boschker, H.T.S.; Tranvik, L.J.

    2015-01-01

    Methane-derived carbon can be important in both benthic and pelagic food webs.Either generated in the anaerobic layers of the sediment or in the anaerobic hypolimnion of stratifiedeutrophic lakes, methane is an excellent carbon source for aerobic methanotrophic bacteria.The very negative methane d13

  4. Sources of uncertainties in modelling black carbon at the global scale

    NARCIS (Netherlands)

    Vignati, E.; Karl, M.; Krol, M.C.; Wilson, J.; Stier, P.; Cavalli, F.

    2010-01-01

    Our understanding of the global black carbon (BC) cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in th

  5. Theoretical study on the carbon nanotube used ashard x—radiation source

    Institute of Scientific and Technical Information of China (English)

    LuJing-Han; QinXi-Jun

    1998-01-01

    Calculations and analyses are made on the interaction between the carbon nanotube and the incident positron of high energy.The results obtained show that it is possible to use carbon nanotube as hard X-radiation source with high intensity and good monochromaticity.

  6. Tracing organic matter sources of estuarine tidal flat nematodes with stable carbon isotopes

    NARCIS (Netherlands)

    Moens, T.; Luyten, C.; Middelburg, J.J.; Herman, P.M.J.; Vincx, M.

    2002-01-01

    The present study explores the use of stable carbon isotopes to trace organic matter sources of intertidal nematodes in the Schelde estuary (SW Netherlands). Stable carbon isotope signatures of nematodes from a saltmarsh and 4 tidal flat stations were determined in spring and winter situations, and

  7. The investments in renewable energy sources: do low carbon economies better invest in green technologies?

    OpenAIRE

    Antonio Angelo Romano; Giuseppe Scandurra (eds.)

    2011-01-01

    The aim of this study is to analyse the driving of investment in renewable energy sources in low carbon and high carbon economies. To address these issues, a dynamic panel analysis of the renewable investment in a sample of 29 countries was proposed. Results demonstrate that the dynamic of investments in renewable sources is similar in the two panels, and depends by nuclear power generation, GDP and technological efficiency. Results show that countries try to reduce their environmental footpr...

  8. Effect of carbon source type on intracellular stored polymers during endogenous denitritation (ED) treating landfill leachate.

    Science.gov (United States)

    Miao, Lei; Wang, Shuying; Li, Baikun; Cao, Tianhao; Zhang, Fangzhai; Wang, Zhong; Peng, Yongzhen

    2016-09-01

    Glycogen accumulating organisms (GAOs) capable of storing organic compounds as polyhydroxyalkanoate (PHA) have been used for endogenous denitritation (ED), but the effect of carbon sources type on nitrogen removal performance of GAOs treating landfill leachate is unclear. In this study, a successful ED system treating landfill leachate (COD/NH4(+)-N (C/N): 4) without external carbon source addition was applied. The mature leachate with C/N of 1 was used as the feeding base solution, with acetate, propionate, and glucose examined as the carbon sources, and their effects on yields and compositions of PHA produced by GAOs were determined and associated with nitrogen removal performance. In the case of sole carbon source, acetate was much easier to be stored than propionate and glucose, which led to a higher nitrogen removal efficiency. Glucose had the lowest amount of PHA storage and led to the lowest performance. In the case of composite carbon sources (two scenarios: acetate + propionate; acetate + propionate + glucose), GAOs stored sufficient PHA and exhibited similar nitrogen removal efficiencies. Moreover, type of carbon source influenced the compositions of PHA. The polyhydroxybutyrate (PHB) fraction in PHA was far more than polyhydroxyvalerate (PHV) in all tests. PHV was synthesized only when acetate existed in carbon source. The microbial diversity analysis revealed that Proteobacteria was the most abundant phylum. Among the 108 genera detected in this ED system, the genera responsible for denitritation were Thauera, Paracoccus, Ottowia and Comamonadaceae_unclassified, accounting for 46.21% of total bacteria. Especially, Paracoccus and Comamonadaceae_unclassified transformed the carbon source into PHA for denitritation, and carried out endogenous denitritation. PMID:27232984

  9. Tracing organic matter sources and carbon burial in mangrove sediments over the past 160 years

    Science.gov (United States)

    Gonneea, Meagan Eagle; Paytan, Adina; Herrera-Silveira, Jorge A.

    2004-10-01

    Mangrove ecosystems may be a source of organic carbon and nutrients to adjacent coastal systems on one hand and provide a sedimentary sink for organic carbon on the other. The balance between these two functions may be sensitive to both natural and anthropogenically induced variability, yet these effects have not been thoroughly evaluated in mangrove ecosystems. We determine organic matter sources and carbon burial rates over the past 160 years in three lagoons on the Yucatan Peninsula, Mexico. Carbon isotopes and C/N elemental ratios are utilized to trace the three sources contributing to sedimentary organic matter, mangroves, seagrasses and phytoplankton, while nitrogen isotopes are used to elucidate potential post-depositional biogeochemical transformations in mangrove lagoon sediments. All three organic matter sources contribute to organic carbon burial. Phytoplankton and mangroves are the dominant sources of organic matter in lagoon bank sediments and seagrasses are a significant source to central lagoon sediments. Organic carbon burial rates are higher at the lagoon fringes, where mangrove vegetation dominates, than in seagrass-dominated mid-lagoon areas. A reduction in mangrove contribution to the sedimentary organic matter pool concurrent with reduced total organic carbon burial rates is observed in the recent past at all three lagoons studied. Natural cycles in sediment organic matter source over the past 160 years are observed in a high-resolution core. These fluctuations correspond to climatic variability in this region, as recorded in deep-sea foraminiferal assemblages. Additional work is required in order to differentiate between recent anthropogenic perturbations and natural variability in organic carbon sources and burial rates within these ecosystems.

  10. Relation of Whole Blood Carboxyhemoglobin Concentration to Ambient Carbon Monoxide Exposure Estimated Using Regression

    OpenAIRE

    Rudra, Carole B.; Williams, Michelle A.; Sheppard, Lianne; Koenig, Jane Q.; Schiff, Melissa A.; Frederick, Ihunnaya O; Dills, Russell

    2010-01-01

    Exposure to carbon monoxide (CO) and other ambient air pollutants is associated with adverse pregnancy outcomes. While there are several methods of estimating CO exposure, few have been evaluated against exposure biomarkers. The authors examined the relation between estimated CO exposure and blood carboxyhemoglobin concentration in 708 pregnant western Washington State women (1996–2004). Carboxyhemoglobin was measured in whole blood drawn around 13 weeks’ gestation. CO exposure during the mon...

  11. Carbon dioxide as working fluid for medium and high-temperature concentrated solar thermal systems

    OpenAIRE

    Duong (fourth author),; Gerardo Diaz

    2014-01-01

    This paper explores the benefits and drawbacks of using carbon dioxide in solar thermal systems at medium and high operating temperatures. For medium temperatures, application of CO2 in non-imaging-optics based compound parabolic concentrators (CPC) combined with evacuated-tube collectors is studied. These collectors have been shown to obtain efficiencies higher than 40% operating at around 200℃ without the need of tracking. Validated numerical models of external compound parabolic concentrat...

  12. Constraining carbon sources and cycling of endolithic microbial communities in the Atacama Desert

    Science.gov (United States)

    Ziolkowski, L. A.; Slater, G. F.; Davila, A.; Wierzchos, J.

    2010-12-01

    The Atacama Desert, one of the driest places on Earth, is considered a suitable analog for the extremely arid, oxidizing conditions on the surface of Mars. Recent observations suggest the presence of evaporitic deposits on the surface of Mars, such as those found in the Atacama. Halites in the Atacama have been shown to be hygroscopic and are colonized by photosynthetic microbes. While there is considerable evidence for the decrease in abundance and diversity of microbes closer to the hyper-arid core of the Atacama, experimental studies have thus far have yet to estimate the sources of carbon to these communities and the rate at which they cycle. To address these questions, we characterized the isotopic composition (13C and 14C) microbial community biomarkers from four distinct sites in the Atacama. Sites ranged from halites in the hyper-arid core (Yungay, Salar Grande) to volcanic rock and gypsum near the Monturaqui Crater. Our analysis of the phospholipids fatty acids (PLFA) and glycolipid fatty acid (GLFA) methyl esters of the endoliths agreed with previous studies: the abundance and diversity of microbes decreases approaching the hyper-arid core. The total PLFA and GLFA concentrations were lower at Yungay than Salar Grande and higher in the gypsum and volcanic rock samples. Changes in the mole percentage distribution of the PLFA and GLFA illustrated that the endolithic communities inhabiting the volcanic rock and gypsum were more complex than those inhabiting the halites. ∂13C of both PLFA and GLFA showed that non-halite lipids were less depleted in 13C than halite-lipids. This suggested a difference in carbon source or cycling. The 14C content of PLFA and GLFA varied by up to 250 per mil. Endolith PLFA and GLFA from the gypsum had radiocarbon signatures comparable to the modern atmosphere, which suggests that the predominant source of carbon to the system is the modern atmosphere and that lipids are cycling rapidly in this system. However, at the other three

  13. Optimization of an Atmospheric Carbon Source for Extremophile Cyanobacteria

    Science.gov (United States)

    Beaubien, Courtney

    This thesis examines the use of the moisture swing resin materials employed at the Center for Negative Carbon Emissions (CNCE) in order to provide carbon dioxide from ambient air to photobioreactors containing extremophile cyanobacteria cultured at the Arizona Center for Algae Technology and Innovation (AzCATI). For this purpose, a carbon dioxide feeding device was designed, built, and tested. The results indicate how much resin should be used with a given volume of algae medium: approximately 500 grams of resin can feed 1% CO2 at about three liters per minute to a ten liter medium of the Galdieria sulphuraria 5587.1 strain for one hour (equivalent to about 0.1 grams of carbon dioxide per hour per seven grams of algae). Using the resin device, the algae grew within their normal growth range: 0.096 grams of ash-free dry weight per liter over a six hour period. Future applications in which the resin-to-algae process can be utilized are discussed.

  14. Intertidal zones as carbon dioxide sources to coastal oceans

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.; George, M.D.; Rajagopal, M.D.

    To understand the factors controlling carbon dioxide (CO sub(2)) exchanges near land-sea boundary diurnal observations have been made twice on CO sub(2) in the air and water in a coastal region. The results suggest that CO sub(2) enrichment...

  15. Process characterization and influence of alternative carbon sources and carbon-to-nitrogen ratio on organic acid production by Aspergillus oryzae DSM1863.

    Science.gov (United States)

    Ochsenreither, Katrin; Fischer, Christian; Neumann, Anke; Syldatk, Christoph

    2014-06-01

    L-Malic acid and fumaric acid are C4 dicarboxylic organic acids and considered as promising chemical building blocks. They can be applied as food preservatives and acidulants in rust removal and as polymerization starter units. Molds of the genus Aspergillus are able to produce malic acid in large quantities from glucose and other carbon sources. In order to enhance the production potential of Aspergillus oryzae DSM 1863, production and consumption rates in an established bioreactor batch-process based on glucose were determined. At 35 °C, up to 42 g/L malic acid was produced in a 168-h batch process with fumaric acid as a by-product. In prolonged shaking flask experiments (353 h), the suitability of the alternative carbon sources xylose and glycerol at a carbon-to-nitrogen (C/N) ratio of 200:1 and the influence of different C/N ratios in glucose cultivations were tested. When using glucose, 58.2 g/L malic acid and 4.2 g/L fumaric acid were produced. When applying xylose or glycerol, both organic acids are produced but the formation of malic acid decreased to 45.4 and 39.4 g/L, respectively. Whereas the fumaric acid concentration was not significantly altered when cultivating with xylose (4.5 g/L), it is clearly enhanced by using glycerol (9.3 g/L). When using glucose as a carbon source, an increase or decrease of the C/N ratio did not influence malic acid production but had an enormous influence on fumaric acid production. The highest fumaric acid concentrations were determined at the highest C/N ratio (300:1, 8.44 g/L) and lowest at the lowest C/N ratio (100:1, 0.7 g/L).

  16. Pan-European modelling of riverine nutrient concentrations - spatial patterns, source detection, trend analyses, scenario modelling

    Science.gov (United States)

    Bartosova, Alena; Arheimer, Berit; Capell, Rene; Donnelly, Chantal; Strömqvist, Johan

    2016-04-01

    Nutrient transport models are important tools for large scale assessments of macro-nutrient fluxes (nitrogen, phosphorus) and thus can serve as support tool for environmental assessment and management. Results from model applications over large areas, i.e. from major river basin to continental scales can fill a gap where monitoring data is not available. Here, we present results from the pan-European rainfall-runoff and nutrient transfer model E-HYPE, which is based on open data sources. We investigate the ability of the E-HYPE model to replicate the spatial and temporal variations found in observed time-series of riverine N and P concentrations, and illustrate the model usefulness for nutrient source detection, trend analyses, and scenario modelling. The results show spatial patterns in N concentration in rivers across Europe which can be used to further our understanding of nutrient issues across the European continent. E-HYPE results show hot spots with highest concentrations of total nitrogen in Western Europe along the North Sea coast. Source apportionment was performed to rank sources of nutrient inflow from land to sea along the European coast. An integrated dynamic model as E-HYPE also allows us to investigate impacts of climate change and measure programs, which was illustrated in a couple of scenarios for the Baltic Sea. Comparing model results with observations shows large uncertainty in many of the data sets and the assumptions used in the model set-up, e.g. point source release estimates. However, evaluation of model performance at a number of measurement sites in Europe shows that mean N concentration levels are generally well simulated. P levels are less well predicted which is expected as the variability of P concentrations in both time and space is higher. Comparing model performance with model set-ups using local data for the Weaver River (UK) did not result in systematically better model performance which highlights the complexity of model

  17. Power plant design with a combined cycle and double concentrated solar thermal power sources

    OpenAIRE

    Vidal i Parreu, Arnau

    2010-01-01

    The electricity has become an indispensable element of today’s society. Demand is growing continuously and the production is still based on limited sources of energy such as coal and petroleum derivate products. Environmental issues, such as global warming, and the uncertainty about the quantity of the conventional fossil fuels are forcing suppliers to find new solutions for the near future. In this assignment, concentrated solar thermal technologies for electricity generation could pla...

  18. CONCENTRATION DISTRIBUTION OF FRACTIONAL ANOMALOUS DIFFUSION CAUSED BY AN INSTANTANEOUS POINT SOURCE

    Institute of Scientific and Technical Information of China (English)

    段俊生; 徐明瑜

    2003-01-01

    The Fox function expression and the analytic expression for the concentration distribution of fractional anomalous diffusion caused by an instantaneous point source in ndimensional space ( n = 1, 2 or 3 ) are derived by means of the condition of mass conservation, the time-space similarity of the solution, Mellin transform and the properties of the Fox function. And the asymptotic behaviors for the solutions are also given.

  19. Characterization of size distributions of elemental mass concentrations in atmospheric aerosols derived from different sources

    International Nuclear Information System (INIS)

    The atmospheric aerosol samples were collected at six representative sites with an 8-stage cascade impactor sampler and analyzed for their elemental mass concentrations by the PIXE analytic method. Based on some indicator elements, the characteristic of size distributions of particles from different sources were obtained. According to these characteristics, we inferred the origins of the ultrafine particles around the Great Wall Station in the Antarctic. (orig.)

  20. Fungal Culture Systems for Production of Antioxidant Phenolics Using Pecan Nut Shells as Sole Carbon Source

    Directory of Open Access Journals (Sweden)

    Miguel A. Medina

    2010-01-01

    Full Text Available Problem statement: Many agro-industrial wastes have little or none utilization, when these materials could be a very rich source of several value-added compounds, such as: the pecan nut shells, which contain Antioxidant Phenolic (AP molecules like tannins. Approach: In this study, a bioprocess for the liberation of AP from Pecan Nut Shells (PNS was described. A chemical characterization of raw material was evaluated to determine polyphenolic content of PNS, among other components. Several fungal culture systems were evaluated at 96 h fermentation processes and using PNS as sole carbon source. Solid (SSC and Submerged (SmC fermentations were carried out using three strains of Aspergillus niger. Culture medium was composed of a solid (10-50% and a liquid (90- 50% part in order to complete the 100% of the medium. Results: A high concentration (19% of tannins was found in PNS on a dry basis, from which condensed tannins and their monomers were found as the main fraction (14% of tannins of PNS, also on a dry basis. In the strain selection step, Aspergillus niger GH1 showed better growth on pecan nut shells compared to A. niger PSH strain, therefore, A. niger GH1 was used for later experiments. The highest concentration of AP was obtained with SSC inoculated with spores of A. niger GH1 on the 40% of solids system and in 20% solids system where, among the other systems both presented 114 mg TP g-1 of phenolics liberation at 24 h of fermentation. PNS is an important source of catechin, being this kind of compound which can be liberated in higher proportion compared to other phenolics compounds. Conclusion: This study demonstrated that fermenting PNS represent a good alternative to both use residues and obtaining AP.

  1. Using an explicit emission tagging method in global modeling of source-receptor relationships for black carbon in the Arctic: Variations, sources, and transport pathways

    Science.gov (United States)

    Wang, Hailong; Rasch, Philip J.; Easter, Richard C.; Singh, Balwinder; Zhang, Rudong; Ma, Po-Lun; Qian, Yun; Ghan, Steven J.; Beagley, Nathaniel

    2014-11-01

    We introduce an explicit emission tagging technique in the Community Atmosphere Model to quantify source-region-resolved characteristics of black carbon (BC), focusing on the Arctic. Explicit tagging of BC source regions without perturbing the emissions provides a physically consistent and computationally efficient approach to establish source-receptor relationships and transport pathways. Our analysis shows that the contributions of major source regions to the global BC burden are not proportional to the respective emissions due to strong region-dependent removal rates and lifetimes, while the contributions to BC direct radiative forcing show a near-linear dependence on their respective contributions to the burden. Arctic BC concentrations, deposition, and source contributions all have strong seasonal variations. Eastern Asia contributes the most to the wintertime Arctic BC burden, but has much less impact on lower-level concentrations and deposition. Northern Europe emissions are more important to both surface concentration and deposition in winter than in summer. The largest contribution to Arctic BC in the summer is from Northern Asia. Although local emissions contribute less than 10% to the annual mean BC burden and deposition within the Arctic, the per-emission efficiency is much higher than for non-Arctic sources. The interannual variability (1996-2005) due to meteorology is small in annual mean BC burden and radiative forcing but is significant in yearly seasonal means over the Arctic. When a slow aging treatment of BC is introduced, the increase of BC lifetime and burden is source dependent. Global BC forcing-per-burden efficiency also increases primarily due to changes in BC vertical distributions.

  2. Distribution of organic carbon and petroleum source rock potential of Cretaceous and lower Tertiary carbonates, South Florida Basin: preliminary results

    Science.gov (United States)

    Palacas, James George

    1978-01-01

    Analyses of 134 core samples from the South Florida Basin show that the carbonates of Comanchean age are relatively richer in average organic carbon (0.41 percent) than those of Coahuilan age (0.28 percent), Gulfian age (0.18 percent) and Paleocene age (0.20 percent). They are also nearly twice as rich as the average world, wide carbonate (average 0.24 percent). The majority of carbonates have organic carbons less than 0.30 percent but the presence of many relatively organic rich beds composed of highly bituminous, argillaceous, highly stylolitic, and algal-bearing limestones and dolomites accounts for the higher percentage of organic carbon in some of the stratigraphic units. Carbonate rocks that contain greater than 0.4 percent organic carbon and that might be considered as possible petroleum sources were noted in almost each subdivision of the Coahuilan and Comanchean Series but particularly the units of Fredericksburg 'B', Trinity 'A', Trinity 'F', and Upper Sunniland. Possible source rocks have been ascribed by others to the Lower Sunniland, but lack of sufficient samples precluded any firm assessment in this initial report. In the shallower section of the basin, organic-rich carbonates containing as much as 3.2 percent organic carbon were observed in the lowermost part of the Gulfian Series and carbonate rocks with oil staining or 'dead' and 'live oil' were noted by others in the uppermost Gulfian and upper Cedar Keys Formation. It is questionable whether these shallower rocks are of sufficient thermal maturity to have generated commercial oil. The South Florida basin is still sparsely drilled and produces only from the Sunniland Limestone at an average depth of 11,500 feet (3500 m). Because the Sunniland contains good reservoir rocks and apparently adequate source rocks, and because the success rate of new oil field discoveries has increased in recent years, the chances of finding additional oil reserves in the Sunniland are promising. Furthermore, the

  3. [Optimization Study on the Nitrogen and Phosphorus Removal of Modified Two- sludge System Under the Condition of Low Carbon Source].

    Science.gov (United States)

    Yang, Wei-qiang; Wang, Dong-bo; Li, Xiao-ming; Yang, Qi; Xu, Qiu-xiang; Zhang, Zhi-bei; Li, Zhi-jun; Xiang, Hai-hong; Wang, Ya-li; Sun, Jian

    2016-04-15

    This paper explored the method of resolving insufficient carbon source in urban sewage by comparing and analyzing denitrification and phosphorus removal (NPR) effect between modified two-sludge system and traditional anaerobic-aerobic-anoxic process under the condition of low carbon source wastewater. The modified two-sludge system was the experimental reactor, which was optimized by adding two stages of micro-aeration (aeration rate 0.5 L · mm⁻¹) in the anoxic period of the original two-sludge system, and multi-stage anaerobic-aerobic-anoxic SBR was the control reactor. When the influent COD, ammonia nitrogen, SOP concentration were respectively 200, 35, 10 mg · L⁻¹, the NPR effect of the experimental reactor was hetter than that of thecontrol reactor with the removal efficiency of TN being 94.8% vs 60.9%, and TP removal being 96.5% vs 75%, respectively. The effluent SOP, ammonia, TN concentration of the experimental reactor were 0.35, 0.50, 1.82 mg · L⁻¹, respectively, which could fully meet the first class of A standard of the Pollutants Emission Standard of Urban Wastewater Treatment Firm (GB 18918-2002). Using the optimized treatment process, the largest amounts of nitrogen and phosphorus removal per unit carbon source (as COD) were 0.17 g · g⁻¹ and 0.048 g · g⁻¹ respectively, which could furthest solve the lower carbon concentration in current municipal wastewater. PMID:27548974

  4. Anthropogenic lead concentrations and sources in Baltic Sea sediments based on lead isotopic composition

    International Nuclear Information System (INIS)

    Highlights: • Pb concentrations reach even 147 μg/g at Gdansk Basin sediments. • Marine sediments deposited before 1860 are not contaminated by Pb. • Contemporary inventories of anthropogenic Pb in marine sediments was of 0.5–11 g for m2. • The lowest 206Pb/207Pb (1.165) were measured in sediments deposited between 1970s–90s. • Coal burning was always the most important Pb source in Poland. - Abstract: The Gulf of Gdańsk is influenced by heavy metals of anthropogenic origin. In this study, temporal concentration changes of Pb, Zn, Cd, and Cu were studied in six, 50 cm long sediment cores. The main aim of the study was to concentrate on the history of Pb fluxes and Pb isotopic composition (206Pb/207Pb and 208Pb/206Pb) to trace Pb sources. The lowest Pb concentrations (19 μg g−1) were measured in sediments deposited circa 1860, while the highest Pb concentrations (63–147 μg g−1) were measured in sediments deposited between 1960s and 70s. Pre-industrial Pb fluxes were 7 Pb m2 year−1, while after WWII they reached 199 Pb m2 year−1. Highest 206Pb/207Pb ratios (∼1.22) were measured in the oldest sediment layers, and the lowest 206Pb/207Pb ratios (∼1.165) were measured in the sediments deposited in 1970s–90s. During the period of highest Pb contamination, the anthropogenic Pb fraction reached up to 93%. A general discussion of the Pb sources, emissions, and loads for Poland is included

  5. Regional background aerosols over the Balearic Islands over the last 3 years: ground-based concentrations, atmospheric deposition and sources

    Science.gov (United States)

    Cerro, Jose Carlos; Pey, Jorge; Bujosa, Carles; Caballero, Sandra; Alastuey, Andres; Sicard, Michael; Artiñano, Begoña; Querol, Xavier

    2013-04-01

    %), sulphate (14%), sea spray (10%), nitrate (7%), NH4 (7%) and elemental carbon (1%), with 21% of the mass unexplained (though as being principally water). Intensive sampling campaigns were positive to assess the concentrations of black carbon and number of ultrafine particles and their time-variability. Accordingly, black carbon followed a similar pattern to that of PM1 but also displayed fresh anthropogenic inputs from road traffic. Number concentration peaked frequently at midday because of new-formation of particles from photochemical reactions, occasionally at hourly values above 100.000 particles per cm3. A preliminary source exploration by means of Principal Component Analysis has been done with the 30-samples group characterized more in detail in terms of chemical determinations. This first examination encountered 6 sources: mineral, sea spray, biomass burning, regional pollution, industry and biogenic emissions. Acknowledgements This work was supported by the Spanish Ministry of Science and Innovation and FEDER funds (CGL2011-13580-E/CLI). ENDESA, through AMBILINE, has been taking care of the instruments most of the time, has provided all the necessary support for the campaign, and has provided data on gaseous pollutants and meteorological parameters.

  6. Wintertime ecosystem respiration shifts tundra from carbon sink to carbon source at tundra warming experiment

    Science.gov (United States)

    Webb, E.; Schuur, E. A.; Natali, S.; Bracho, R.

    2013-12-01

    Northern latitude ecosystems play a significant role in the global carbon (C) budget due to the roughly 1700 Pg of C stored in permafrost soils. As high latitudes warm, previously frozen C is expected to decompose, thereby increasing CO2 fluxes to the atmosphere and potentially creating a positive feedback to climate warming. While warming has been shown to increase plant C uptake during the growing season, these seasonal C gains may be offset on an annual basis by ecosystem respiration (Reco) during the remaining seven months of the year. Here we present research from the Carbon in Permafrost Experimental Heating Research (CiPEHR) project, a tundra ecosystem warming experiment in interior Alaska. We partitioned the non-growing season into three segments: fall (October 1 until first snow), winter (snow-covered period until spring), and spring (snow depth less than 30cm until melt out). During fall, we measured net ecosystem exchange and Reco using a static flux chamber. In winter, we measured Reco using chamber measurements and soda lime. For spring, we modeled fluxes based on known relationships between snow depth and photosynthetic rate of arctic evergreen species. We found that ecosystem warming caused plants to photosynthesize later in fall and increased C uptake during spring but also enhanced respiration during the long winter. We combined these off-season estimates with measurements from growing season auto-chamber data and found that despite the C gained during the growing season, ecosystem warming resulted in net annual C loss for the two years measured. This annual C loss was dependent on the magnitude of wintertime Reco. Our results indicate that snow depth, soil temperature, and day of season are the major determinants of wintertime Reco. Some climate models predict that arctic ecosystems will experience warmer winters with more snow. Thus, despite increased plant productivity during the growing season, we document that increased wintertime temperatures

  7. Development of a stationary carbon emission inventory for Shanghai using pollution source census data

    Science.gov (United States)

    Li, Xianzhe; Jiang, Ping; Zhang, Yan; Ma, Weichun

    2016-03-01

    This study utilizes 521,631 activity data points from the 2007 Shanghai Pollution Source Census to compile a stationary carbon emission inventory for Shanghai. The inventory generated from our dataset shows that a large portion of Shanghai's total energy use consists of coal-oriented energy consumption. The electricity and heat production industries, iron and steel mills, and the petroleum refining industry are the main carbon emitters. In addition, most of these industries are located in Baoshan District, which is Shanghai's largest contributor of carbon emissions. Policy makers can use the enterpriselevel carbon emission inventory and the method designed in this study to construct sound carbon emission reduction policies. The carbon trading scheme to be established in Shanghai based on the developed carbon inventory is also introduced in this paper with the aim of promoting the monitoring, reporting and verification of carbon trading. Moreover, we believe that it might be useful to consider the participation of industries, such as those for food processing, beverage, and tobacco, in Shanghai's carbon trading scheme. Based on the results contained herein, we recommend establishing a comprehensive carbon emission inventory by inputting data from the pollution source census used in this study.

  8. Changing sources and sinks of carbon in boreal ecosystems of Interior Alaska: Current and future perspectives

    Science.gov (United States)

    Douglas, T. A.; Jones, M.; Hiemstra, C. A.

    2012-12-01

    Future climate scenarios predict a roughly 5°C increase in mean annual air temperatures for the Alaskan Interior over the next 80 years. Increasing temperatures and greater frequency and severity of climate-induced disturbances such as wildfires will be enough to initiate permafrost degradation in many areas of Alaska, leading to major changes in surface hydrology and ecosystem structure and function. This, in turn, is expected to alter the current inventories of carbon sources and sinks in the region and provide a management challenge for carbon itemization efforts. To assist land managers in adapting and planning for potential changes in Interior Alaska carbon cycling we synthesize information on climate, ecosystem processes, vegetation, and soil, permafrost, and hydrologic regimes in Interior Alaska. Our goal is to provide an assessment of the current and likely future regime of Interior Alaska carbon sources and sinks. For our carbon assessment we: 1) synthesize the most recent results from numerous studies on the carbon cycle with a focus on research from the Alaskan boreal biome, 2) assemble a summary of estimates of carbon sources in soil and vegetation in Interior Alaska, 3) categorize carbon sources and sinks for predominant Interior Alaska ecosystems, and 4) identify expected changes in sources and sinks with climate change and human activities. This information is used to provide recommendations on potential actions land managers can take to minimize carbon export from the boreal forest. Though the results from our project are geared primarily toward policy makers and land managers we also provide recommendations for filling research gaps that currently present uncertainty in our understanding of the carbon cycle in boreal forest ecosystems of Interior Alaska.

  9. Dynamic balancing of isoprene carbon sources reflects photosynthetic and photorespiratory responses to temperature stress.

    Science.gov (United States)

    Jardine, Kolby; Chambers, Jeffrey; Alves, Eliane G; Teixeira, Andrea; Garcia, Sabrina; Holm, Jennifer; Higuchi, Niro; Manzi, Antonio; Abrell, Leif; Fuentes, Jose D; Nielsen, Lars K; Torn, Margaret S; Vickers, Claudia E

    2014-12-01

    The volatile gas isoprene is emitted in teragrams per annum quantities from the terrestrial biosphere and exerts a large effect on atmospheric chemistry. Isoprene is made primarily from recently fixed photosynthate; however, alternate carbon sources play an important role, particularly when photosynthate is limiting. We examined the relative contribution of these alternate carbon sources under changes in light and temperature, the two environmental conditions that have the strongest influence over isoprene emission. Using a novel real-time analytical approach that allowed us to examine dynamic changes in carbon sources, we observed that relative contributions do not change as a function of light intensity. We found that the classical uncoupling of isoprene emission from net photosynthesis at elevated leaf temperatures is associated with an increased contribution of alternate carbon. We also observed a rapid compensatory response where alternate carbon sources compensated for transient decreases in recently fixed carbon during thermal ramping, thereby maintaining overall increases in isoprene production rates at high temperatures. Photorespiration is known to contribute to the decline in net photosynthesis at high leaf temperatures. A reduction in the temperature at which the contribution of alternate carbon sources increased was observed under photorespiratory conditions, while photosynthetic conditions increased this temperature. Feeding [2-(13)C]glycine (a photorespiratory intermediate) stimulated emissions of [(13)C1-5]isoprene and (13)CO2, supporting the possibility that photorespiration can provide an alternate source of carbon for isoprene synthesis. Our observations have important implications for establishing improved mechanistic predictions of isoprene emissions and primary carbon metabolism, particularly under the predicted increases in future global temperatures. PMID:25318937

  10. Using hydrocarbon as a carbon source for synthesis of carbon nanotube by electric field induced needle-pulsed plasma

    International Nuclear Information System (INIS)

    In this work different hydrocarbons are used as the carbon source, in the production of carbon nanotubes (CNTs) and nano onions. An electric field induced needle pulse arc-discharge reactor is used. The influence of starting carbon on the synthesis of CNTs is investigated. The production efficiency is compared for Acetone, Isopropanol and Naphthalene as simple hydrocarbons. The hydrocarbons are preheated and then pretreated by electric field before being exposed to plasma. The hydrocarbon vapor is injected into plasma through a graphite spout in the cathode assembly. The pulsed plasma takes place between two graphite rods while a strong electric field has been already established alongside the electrodes. The pulse width is 0.3 μs. Mechanism of precursor decomposition is discussed by describing three forms of energy that are utilized to disintegrate the precursor molecules: thermal energy, electric field and kinetic energy of plasma. Molecular polarity of a hydrocarbon is one of the reasons for choosing carbon raw material as a precursor in an electric field induced low power pulsed-plasma. The results show that in order to obtain high quality carbon nanotubes, Acetone is preferred to Isopropanol and Naphthalene. Scanning probe microscopy techniques are used to investigate the products. - Highlights: • We synthesized CNTs (carbon nano tubes) by needle pulsed plasma. • We use different hydrocarbons as carbon source in the production of CNTs. • We investigated the influence of starting carbon on the synthesis of CNTs. • Thermal energy, electric field and kinetic energy are used to break carbon bonds. • Polar hydrocarbon molecules are more efficient than nonpolar ones in production

  11. Modified Weighting for Calculating the Average Concentration of Non-Point Source Pollutant

    Institute of Scientific and Technical Information of China (English)

    牟瑞芳

    2004-01-01

    The concentration of runoff depends upon that of soil loss and the latter is assumed to be linear to the value of EI that equals the product of total storm energy E times the maximum 30-min intensity I30 for a given rainstorm. Usually, the maximum accumulative amount of rain for a rainstorm might bring on the maximum amount of runoff, but it does not equal the maximum erosion and not always lead the maximum concentration. Thus, the average concentration weighted by amount of runoff is somewhat unreasonable. An improvement for the calculation method of non-point source pollution load put forward by professor Li Huaien is proposed. In replacement of the weight of runoff, EI value of a single rainstorm is introduced as a new weight. An example of Fujing River watershed shows that its application is effective.

  12. Effects of dietary vitamin E concentration and source on sow, milk, and pig concentrations of α-tocopherol.

    Science.gov (United States)

    Shelton, N W; Dritz, S S; Nelssen, J L; Tokach, M D; Goodband, R D; DeRouchey, J M; Yang, H; Hill, D A; Holzgraefe, D; Hall, D H; Mahan, D C

    2014-10-01

    A total of 126 gilts and sows (PIC 1050) and their litters were used to determine the effects of dietary vitamin E concentration and source on sow plasma, milk, and pig concentrations of α-tocopherol. Additionally, we estimated the bioavailability of D-α-tocopheryl acetate (D-α-TAc) relative to DL-α-tocopheryl acetate (DL-α-TAc) when fed in diets containing dried distillers grains with solubles (DDGS). The 6 dietary treatments included DL-α-TAc at 44 and 66 mg/kg and D-α-TAc at 11, 22, 33, and 44 mg/kg. From breeding to d 69 of gestation, sows were fed 2.0 kg/d of a diet containing 40% DDGS, 0.30 mg/kg added Se, and no added vitamin E. Vitamin E treatments were fed from d 70 of gestation through weaning. Plasma was collected from sows on d 69 and 100 of gestation, at farrowing, and at weaning. Colostrum and milk samples were also collected. Plasma from 3 pigs per litter and heart and liver samples from 1 pig per litter were collected at weaning. Plasma, milk, and tissues from 6 litters per treatment were analyzed for α-tocopherol. Although tissue, plasma, and milk concentrations of α-tocopherol were the primary response criteria of interest, sow and litter performance were measured. As expected, treatment effects were not observed for lactation feed intake, sow BW, or backfat measurements. A trend (P = 0.085) for a treatment effect on average pig BW at weaning was detected, with pigs nursing sows fed 44 mg/kg DL-α-TAc weighing less because of a younger weaning age. No other differences in litter performance were observed. As D-α-TAc increased in the diet, sow plasma, colostrum, and milk, pig plasma, and pig heart concentrations of α-tocopherol increased (linear, P Sows fed diets with 44 mg/kg D-α-TAc had increased (P sows fed 44 mg/kg of DL-α-TAc. Sows fed 66 mg/kg DL-α-TAc also had greater (P = 0.022) plasma α-tocopherol at weaning than sows fed 44 mg/kg DL-α-TAc. Bioavailability coefficients for D-α-TAc relative to DL-α-TAc ranged from 1.9 to 4

  13. Study on the threshold value of organic enrichment of carbonate as gas source rocks

    Institute of Scientific and Technical Information of China (English)

    XUE; Haitao; LU; Shuangfang; ZHONG; Ningning; WANG; Bo

    2004-01-01

    In this paper, calculations have been performed about gas quantity of generation, adsorption, dissolving in oil, dissolving in water, diffusion of unit area carbonate rocks at different geologic conditions in the Tarim basin. According to the material balance principle, the corresponding organic carbon content when gas started expelling from source rocks with separate phases has been worked out. We regard it as the theoretical threshold value (TOCmin) of gas source rocks under the same geologic condition. Based on the simulating calculation, a fact has been discovered that TOCmin decreases with the increasing source rocks thickness, decreases at the beginning and then increases with the increasing maturity and decreases with the better type of organic matter. TOCmin evaluation table of carbonate gas source rocks in the Tarim basin has been established. Investigations indicate that the TOCmin of carbonate gas source rocks varies greatly with the differences of geologic conditions, and gas source rocks cannot be evaluated with a unified TOC threshold value. And we also establish a preliminary evaluation table of TOC industrial threshold value, TOCgy, of carbonate gas source rocks in the Tarim basin.

  14. Estimating the seasonal carbon source-sink geography of a natural, steady-state terrestrial biosphere

    Science.gov (United States)

    Box, Elgene O.

    1988-01-01

    The estimation of the seasonal dynamics of biospheric-carbon sources and sinks to be used as an input to global atmospheric CO2 studies and models is discussed. An ecological biosphere model is given and the advantages of the model are examined. Monthly maps of estimated biospheric carbon source and sink regions and estimates of total carbon fluxes are presented for an equilibrium terrestrial biosphere. The results are compared with those from other models. It is suggested that, despite maximum variations of atmospheric CO2 in boreal latitudes, the enormous contributions of tropical wet-dry regions to global atmospheric CO2 seasonality can not be ignored.

  15. Carbon Sources to Authigenic Carbonate Rock at Chemosynthetic Communities: Lower Slope of the Gulf of Mexico

    Science.gov (United States)

    Sassen, R.; Jung, W.; Zhang, C.; Defreitas, D. A.

    2004-12-01

    Flux of biogenic methane, crude oil and associated hydrocarbon gases occurs from the deep subsurface to the seafloor, water column, and atmosphere of the Gulf of Mexico slope. Chemosynthetic communities occur at sites of relatively high gas flux, frequently with gas hydrate, but always with authigenic carbonate rock \\(ACR\\). ACR contains carbonate carbon derived from microbial hydrocarbon oxidation that geologically sequesters much fossil carbon, perturbing the carbon cycle. ACR was collected using the ALVIN from sites with chemosynthetic communities in Alaminos Canyon, Atwater Valley, and the Florida Escarpment areas at water depths as much as 3.3 km. Bulk δ 13C was measured and carbonate petrology used to identify carbonate cements, normal marine carbonate, and non-carbonate components such as metal oxides and sulfides. ACR is depleted in 13C. However, the δ 13C of major hydrocarbon types is typically more depleted in 13C than the associated ACR. For example, the mean δ 13C of biogenic methane seeps in the Gulf slope is -74.0\\permil PDB but the lightest bulk ACR measured in the study area is -46.6\\permil PDB. Carbonate cements from hydrocarbon oxidation are shown to enclose skeletal remains of chemosynthetic fauna such as mussels, clams, as well as other fauna characterized by normal marine carbonate \\(\\sim 0\\permil PDB\\). The best explanation of why the δ 13C of ACR does not closely correspond to that of the hydrocarbon starting products is that normal marine carbon dilutes the δ 13C from hydrocarbon oxidation and thus affects the bulk isotopic properties of ACR.

  16. Antifungal activity of clotrimazole against Candida albicans depends on carbon sources, growth phase and morphology.

    Science.gov (United States)

    Kasper, Lydia; Miramón, Pedro; Jablonowski, Nadja; Wisgott, Stephanie; Wilson, Duncan; Brunke, Sascha; Hube, Bernhard

    2015-07-01

    Vulvovaginal candidiasis, a superficial infection caused predominantly by the pathogenic fungus Candida albicans, is frequently treated with clotrimazole. Some drug formulations contain lactate for improved solubility. Lactate may modify C. albicans physiology and drug sensitivity by serving as a carbon source for the fungus and/or affecting local pH. Here, we explored the effects of lactate, in combination with pH changes, on C. albicans proliferation, morphology and clotrimazole sensitivity. Moreover, we determined the influence of growth phase and morphology per se on drug sensitivity. We showed that utilization of lactate as a carbon source did not promote fast fungal proliferation or filamentation. Lactate had no influence on clotrimazole-mediated killing of C. albicans in standard fungal cultivation medium but had an additive effect on the fungicidal clotrimazole action under in vitro vagina-simulative conditions. Moreover, clotrimazole-mediated killing was growth-phase and morphology dependent. Post-exponential cells were resistant to the fungicidal action of clotrimazole, whilst logarithmic cells were sensitive, and hyphae showed the highest susceptibility. Finally, we showed that treatment of pre-formed C. albicans hyphae with sublethal concentrations of clotrimazole induced a reversion to yeast-phase growth. As C. albicans hyphae are considered the pathogenic morphology during mucosal infections, these data suggest that elevated fungicidal activity of clotrimazole against hyphae plus clotrimazole-induced hyphae-to-yeast reversion may help to dampen acute vaginal infections by reducing the relative proportion of hyphae and thus shifting to a non-invasive commensal-like population. In addition, lactate as an ingredient of clotrimazole formulations may potentiate clotrimazole killing of C. albicans in the vaginal microenvironment. PMID:25976001

  17. Could 4 degrees warming change Arctic tundra from carbon sink to carbon source?

    Science.gov (United States)

    Torn, M. S.; Abramoff, R. Z.; Chafe, O.; Curtis, J. B.; Smith, L. J.; Wullschleger, S. D.

    2015-12-01

    We have set up a controlled, active warming experiment in permafrost tundra on the North Slope of Alaska. The aim of this micro-warming experiment is to investigate the direct effect of soil warming on microbial decomposition of soil organic matter. We are testing the feasibility of small, short-term, in situ warming that can be run off batteries for distributed deployment and that preserves plant-soil relations and natural variability in wind, temperature, and precipitation. Based on preliminary results, the approach looks promising. One resistance heater cable per plot (25 cm diameter plots) was inserted vertically to 50 cm, spanning the full active layer (maximum thaw depth was 40 cm in 2014). Heaters were turned on August 1, 2015, and heated plots reached the 4ºC warming target within 1-3 days. We are measuring soil microclimate, thaw depth, CO2 and CH4 fluxes, and 14CO2, and microbial composition, as part of the DOE Next Generation Ecosystem Experiments (NGEE-Arctic). Ecosystem respiration increased immediately in the heated plots, and net ecosystem exchange under clear chambers changed from net uptake to net CO2 source in two of the four plots. CH4 flux shifted toward reduced net emissions or greater net uptake in all plots. These rapid responses demonstrate direct changes in decomposition without complications from microbial acclimation, altered community structure or changes in substrate availability. However, future Arctic tundra carbon balance will depend on both short term and long term microbial responses, as well as the links between warming, decomposition, nitrogen mineralization, and plant growth. Thus, we envision that distributed micro-warming plots could be combined with new approaches to aboveground passive warming being developed in NGEE, gradient studies, and modeling.

  18. Water-soluble organic carbon in urban aerosol: concentrations, size distributions and contribution to particulate matter

    Energy Technology Data Exchange (ETDEWEB)

    Timonen, H. J.; Saarikoski, S. K.; Aurela, M. A.; Saarnio, K. M.; Hillamo, R. E. (Finnish Meteorological Inst., Helsinki (Finland))

    2008-07-01

    The aim of this study was to characterize the concentrations and particle mass size distributions of water-soluble organic carbon (WSOC) in urban aerosols. The sample collection was carried out in spring 2006 at the SMEAR III station in Helsinki, Finland, by using a size-segregating method (MOUDI) and by collecting sub-micrometer fraction of aerosols on the filter. During the three-month measurement period, a major 12-day biomass burning pollution episode was observed. Concentrations of WSOC, organic carbon, monosaccharide anhydrides, inorganic ions and some organic acids (oxalic, succinic and malonic acid) were analyzed from the PM{sub 1} samples. The measured OC and WSOC concentrations varied in ranges 0.67-15.7 mug m-3 and 0.26-10.7 mug m3, respectively. The WSOC/OC concentration ratio was between 0.30 and 0.89 with an average of 0.54. Size distributions of WSOC, inorganic ions and total mass were determined from the MOUDI samples. WSOC had bimodal size distributions with a clear accumulation mode below 1 mum of particle aerodynamic diameter and minor coarse mode at sizes > 1 mum. (orig.)

  19. Characterization of aerosol composition, concentrations, and sources at Baengnyeong Island, Korea using an aerosol mass spectrometer

    Science.gov (United States)

    Lee, Taehyoung; Choi, Jinsoo; Lee, Gangwoong; Ahn, Junyoung; Park, Jin Soo; Atwood, Samuel A.; Schurman, Misha; Choi, Yongjoo; Chung, Yoomi; Collett, Jeffrey L.

    2015-11-01

    To improve understanding of the sources and chemical properties of particulate pollutants on the western side of the Korean Peninsula, an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) measured non-refractory fine (PM1) particles from May to November, 2011 at Baengnyeong Island, South Korea. Organic matter and sulfate were generally the most abundant species and exhibited maximum concentrations of 36 μg/m3 and 39 μg/m3, respectively. Nitrate concentrations peaked at 32 μg/m3 but were typically much lower than sulfate and organic matter concentrations. May, September, October, and November featured the highest monthly average concentrations, with lower concentrations typically observed from June through August. Potential source contribution function (PSCF) analysis and individual case studies revealed that transport from eastern China, an area with high SO2 emissions, was associated with high particulate sulfate concentrations at the measurement site. Observed sulfate aerosol sometimes was fully neutralized by ammonium but often was acidic; the average ammonium to sulfate molar ratio was 1.49. Measured species size distributions revealed a range of sulfate particle size distributions with modes between 100 and 600 nm. Organic aerosol source regions were widespread, including contributions from eastern China and South Korea. Positive matrix factorization (PMF) analysis indicated three "factors," or types of organic aerosol, comprising one primary, hydrocarbon-like organic aerosol (HOA) and two oxidized organic aerosol (OOA) components, including a more oxidized (MO-OOA) and a less oxidized (LO-OOA) oxidized organic aerosol. On average, HOA and OOA contributed 21% and 79% of the organic mass (OM), respectively, with the MO-OOA fraction nearly three times as abundant as the LO-OOA fraction. Biomass burning contributions to observed OM were low during the late spring/early summer agricultural burning season in eastern China, since

  20. On the source contribution to Beijing PM2.5 concentrations

    Science.gov (United States)

    Zíková, Naděžda; Wang, Yungang; Yang, Fumo; Li, Xinghua; Tian, Mi; Hopke, Philip K.

    2016-06-01

    Beijing is a city with some of the world's worst particulate air pollution. Although there have been various control strategies implemented since 1998, there are still episodes of PM2.5 concentrations of hundreds of micrograms per cubic meter. In this study, samples were collected over a year in Beijing, chemically characterized, and the resulting data analyzed for source apportionment. The new error analysis capabilities built into EPA PMF V5.0 have been employed to better evaluate the profiles and assign them to source types. Secondary sulfate, local coal combustion and secondary nitrate were the major contributors to the PM2.5 mass. However, in this study, traffic was found to be more important as a PM compared to prior studies. It was actually the largest PM2.5 source in autumn and winter although local coal combustion is also a large source of PM in the winter months. These results demonstrate the value of using the displacement method to assess the variability in source profiles to improve our interpretation of PMF results. They also suggest more attention needs to be paid to traffic emissions in Beijing.

  1. Sources of carbon monoxide and formaldehyde in North America determined from high-resolution atmospheric data

    Directory of Open Access Journals (Sweden)

    S. M. Miller

    2008-06-01

    Full Text Available We analyze the North American budget for carbon monoxide using data for CO and formaldehyde concentrations from tall towers and aircraft in a model-data assimilation framework. The Stochastic Time-Inverted, Lagrangian Transport model for CO (STILT-CO determines local to regional-scale CO contributions associated with production from fossil fuel combustion, biomass burning, and oxidation of volatile organic compounds (VOCs using an ensemble of Lagrangian particles driven by high resolution assimilated meteorology. In most cases, the model demonstrates high fidelity simulations of hourly surface data from tall towers and point measurements from aircraft, with somewhat less satisfactory performance in coastal regions and when CO from large biomass fires in Alaska and the Yukon Territory influence the continental US.

    Inversions of STILT-CO simulations for CO and formaldehyde show that current inventories of CO emissions from fossil fuel combustion are significantly too high, by almost a factor of three in summer and a factor two in early spring, consistent with recent analyses of data from the INTEX-A aircraft program. Formaldehyde data help to show that sources of CO from oxidation of CH4 and other VOCs represent the dominant sources of CO over North America in summer.

  2. Determining sources of dissolved organic carbon and disinfection byproduct precursors to the McKenzie River, Oregon

    Science.gov (United States)

    Kraus, T.E.C.; Anderson, C.A.; Morgenstern, K.; Downing, B.D.; Pellerin, B.A.; Bergamaschi, B.A.

    2010-01-01

    This study was conducted to determine the main sources of dissolved organic carbon (DOC) and disinfection byproduct (DBP) precursors to the McKenzie River, Oregon (USA). Water samples collected from the mainstem, tributaries, and reservoir outflows were analyzed for DOC concentration and DBP formation potentials (trihalomethanes [THMFPs] and haloacetic acids [HAAFPs]). In addition, optical properties (absorbance and fluorescence) of dissolved organic matter (DOM) were measured to provide insight into DOM composition and assess whether optical properties are useful proxies for DOC and DBP precursor concentrations. Optical properties indicative of composition suggest that DOM in the McKenzie River mainstem was primarily allochthonous - derived from soils and plant material in the upstream watershed. Downstream tributaries had higher DOC concentrations than mainstem sites (1.6 ?? 0.4 vs. 0.7 ?? 0.3 mg L-1) but comprised rain event in the fall contributes DOM with high DBP precursor content. Although there was interference in the absorbance spectra in downstream tributary samples, fluorescence data were strongly correlated to DOC concentration (R 2 = 0.98), THMFP (R2 = 0.98), and HAAFP (R2 = 0.96). These results highlight the value of using optical measurements for identifying the concentration and sources of DBP precursors in watersheds, which will help drinking water utilities improve source water monitoring and management programs. Copyright ?? 2010 by the American Society of Agronomy.

  3. Hydrogen and Carbon Stable Isotopic Compositions and Concentrations of Methane in Cave Air of Cueva de Villa Luz, Tabasco, Mexico

    Science.gov (United States)

    Webster, K.; Rosales Lagarde, L.; Sauer, P. E.; Schimmelmann, A.; Lennon, J. T.; Boston, P. J.

    2014-12-01

    Cueva de Villa Luz (CVL) is a unique biogeochemical environment where microbial consortia are supported by hydrogen sulfide (H2S) leading to sulfuric acid speleogenesis (SAS) which is thought to have generated the porosity and permeability of several petroleum reservoirs. Possible sources of the sulfur (S) include the Chichón Volcano and petroleum basins in the area. A better understanding of the source of the H2S in CVL may help predict where else SAS may have occurred. Analysis of methane (CH4) in CVL may provide a proxy to assess the source of S entering CVL. We obtained 13 air samples in 1-L Tedlar® bags from varying locations in CVL to assess the role of CH4 in sulfide-rich karst systems. CH4 and carbon dioxide (CO2) concentrations were measured by gas-chromatography. The stable isotopic ratios of carbon and hydrogen were measured on a stable isotope-ratio mass-spectrometer. CH4 in the air of CVL ranged from 1.88 ± 0.10 ppmv to 3.7 ± 0.2 ppmv. CO2 concentrations ranged from 400 ± 20 ppmv to 920 ± 50 ppmv. For comparison, the CH4 and CO2 concentrations in the outside atmosphere were 1.96 ± 0.10 ppmv and 430 ± 20 ppmv respectively. CH4 and CO2 were positively correlated in CVL (R2 = 0.91, CH4 = [0.0035 ± 0.0007] CO2 + [0.4 ± 0.4], p >0.01). The highest concentrations were near springs. Keeling-style analysis showed that the CH4 samples from CVL plot along a two-end member mixing model and suggest that CH4 is outgassing from spring water with isotopic compositions δ13CCH4 = -24 ± 3 ‰ and δ2HCH4 = -40 ± 40 ‰. CO2 did not plot along a two end member mixing model. The proposed δ13C of CH4 entering from springs does not closely match the δ13CCH4 values from hydrocarbon basins in the area. This is likely due to oxidative loss of CH4 as it ascends to CVL which may be partly driven by anaerobic methanotrophy coupled to sulfate reduction. Analysis of the spring water chemistry coupled to biogeochemical modeling may help quantify the amount of

  4. Mapping Air Pollution Concentrations and Sources in China from Ground-Level Observations

    Science.gov (United States)

    Rohde, R. A.; Muller, R. A.

    2014-12-01

    China has recently established an extensive air quality monitoring system with over 1500 sites providing hourly data on airborne particulate matter (PM2.5 / PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), and carbon monoxide (CO). Based on Kriging interpolation of these surface data, we derive a detailed map of air pollution across the eastern half of China. In northern and central China, the pollution is widespread; contrary to popular belief, pollution is not simply localized to major cities such as Beijing, Shanghai, or Chongqing, or in geologic basins. Pollution levels are lower in southern China, in part due to frequent rains. By incorporating wind measurements and estimating pollution transport, we also infer source distributions for key pollutants. Sources are widespread, but many of the largest sources are often situated in or near major population centers. A northeast corridor extending from near Shanghai to north of Beijing includes many of the most significant pollution sources in China. Roughly 5% of the study region accounts for 25% of observed particulate matter emissions. During the analysis period, roughly half of the population of China was subjected to a long-term average pollution level in the unhealthy range, according to standards used by the US Environmental Protection Agency. In addition, nearly all of China's population (>90%) was exposed to unhealthy levels of air pollution at least some of the time. Based on health impact estimates from the Huai River Study, we estimate that the observed levels of particulate matter pollution contribute to about 1.4 million deaths every year in China, about 3500 per day, in agreement with prior estimates. Identification of sources from pollution data was facilitated by the reporting of hourly measurements, and we encourage other nations around the world to follow China's example and provide such time-resolved data.

  5. Electron string ion sources for carbon ion cancer therapy accelerators

    CERN Document Server

    Boytsov, A Yu; Donets, E D; Donets, E E; Katagiri, K; Noda, K; Ponkin, D O; Ramzdorf, A Yu; Salnikov, V V; Shutov, V B

    2015-01-01

    The Electron String type of Ion Sources (ESIS) was developed, constructed and tested first in the Joint Institute for Nuclear Research. These ion sources can be the appropriate sources for production of pulsed C4+ and C6+ ion beams which can be used for cancer therapy accelerators. In fact the test ESIS Krion-6T already now at the solenoid magnetic field only 4.6 T provides more than 10^10 C4+ ions per pulse and about 5*10^9 C6+ ions per pulse. Such ion sources could be suitable for application at synchrotrons. It was also found, that Krion-6T can provide more than 10^11 C6+ ions per second at 100 Hz repetition rate, and the repetition rate can be increased at the same or larger ion output per second. This makes ESIS applicable at cyclotrons as well. As for production of 11C radioactive ion beams ESIS can be the most economic kind of ion source. To proof that the special cryogenic cell for pulse injection of gaseous species into electron string was successfully tested using the ESIS Krion-2M.

  6. A repeat protein links Rubisco to form the eukaryotic carbon-concentrating organelle.

    Science.gov (United States)

    Mackinder, Luke C M; Meyer, Moritz T; Mettler-Altmann, Tabea; Chen, Vivian K; Mitchell, Madeline C; Caspari, Oliver; Freeman Rosenzweig, Elizabeth S; Pallesen, Leif; Reeves, Gregory; Itakura, Alan; Roth, Robyn; Sommer, Frederik; Geimer, Stefan; Mühlhaus, Timo; Schroda, Michael; Goodenough, Ursula; Stitt, Mark; Griffiths, Howard; Jonikas, Martin C

    2016-05-24

    Biological carbon fixation is a key step in the global carbon cycle that regulates the atmosphere's composition while producing the food we eat and the fuels we burn. Approximately one-third of global carbon fixation occurs in an overlooked algal organelle called the pyrenoid. The pyrenoid contains the CO2-fixing enzyme Rubisco and enhances carbon fixation by supplying Rubisco with a high concentration of CO2 Since the discovery of the pyrenoid more that 130 y ago, the molecular structure and biogenesis of this ecologically fundamental organelle have remained enigmatic. Here we use the model green alga Chlamydomonas reinhardtii to discover that a low-complexity repeat protein, Essential Pyrenoid Component 1 (EPYC1), links Rubisco to form the pyrenoid. We find that EPYC1 is of comparable abundance to Rubisco and colocalizes with Rubisco throughout the pyrenoid. We show that EPYC1 is essential for normal pyrenoid size, number, morphology, Rubisco content, and efficient carbon fixation at low CO2 We explain the central role of EPYC1 in pyrenoid biogenesis by the finding that EPYC1 binds Rubisco to form the pyrenoid matrix. We propose two models in which EPYC1's four repeats could produce the observed lattice arrangement of Rubisco in the Chlamydomonas pyrenoid. Our results suggest a surprisingly simple molecular mechanism for how Rubisco can be packaged to form the pyrenoid matrix, potentially explaining how Rubisco packaging into a pyrenoid could have evolved across a broad range of photosynthetic eukaryotes through convergent evolution. In addition, our findings represent a key step toward engineering a pyrenoid into crops to enhance their carbon fixation efficiency. PMID:27166422

  7. Elucidating Geochemical Controls on the Concentration and Composition of Organic Carbon in Deep Pelagic Sediments

    Science.gov (United States)

    Estes, E. R.; Hansel, C. M.; Anderson, C. H.; Murray, R. W.; Dyar, M. D.; Nordlund, D.; Wankel, S. D.; Johnson, D.; Spivack, A. J.; Sauvage, J.; McKinley, C. C.; Homola, K.; Present, T. M.; Pockalny, R. A.; D'Hondt, S.

    2015-12-01

    In marine sediments, total organic carbon (OC) content correlates strongly with mineral surface area as well as the abundance of specific mineral classes such as clays and metal oxides. Adsorption to mineral surfaces and the formation of mineral-organic matter aggregates are thought to provide protection against remineralization, yet the extent and mechanism(s) of this protection are unknown. Accordingly, the goal of this research is to elucidate the role of minerals in preserving carbon and the potential for this reservoir of mineral-hosted carbon to support heterotrophic metabolisms in the otherwise carbon-poor subseafloor. Here, we characterize the composition of OC in oxic and suboxic sediments collected during R/V Knorr expedition 223 to the subtropical western North Atlantic in November 2014. We find that OC concentrations decrease linearly over ~25 meters burial depth, from ~0.15 to 0.075 mol OC/kg solid. Organic C/N varies but is consistently less than Redfield values of ~6. Relative contributions of functional groups quantified using bulk-scale Fourier transform infrared (FTIR) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy change with depth and site lithology/geochemistry. We further observe microscale heterogeneity, including discrete carbonate particles amid disperse aromatic and amide/carboxylic-rich organic carbon, using scanning transmission X-ray microscopy (STXM) coupled to NEXAFS. In the suboxic sediments, there is a transition from Mn(III/IV) phases toward more reduced phases shown by X-ray absorption spectroscopy between ~3-11 meters below core top, approximately between the interstitial water nitrate and nitrite maxima. Conversely, Fe(III)-bearing minerals are present throughout the core and may contribute to stabilization of OC. By further coupling micro- and macro-scale analysis, the role of minerals in OC sequestration in the marine subsurface will come to light.

  8. The effect of mitigation measures on size distributed mass concentrations of atmospheric particles and black carbon concentrations during the Olympic Summer Games 2008 in Beijing.

    Science.gov (United States)

    Schleicher, Nina; Norra, Stefan; Dietze, Volker; Yu, Yang; Fricker, Mathieu; Kaminski, Uwe; Chen, Yuan; Cen, Kuang

    2011-12-15

    The period of the 2008 Olympic Summer Games in Beijing can be considered as a unique opportunity to study the influences of emission reduction measures on air quality improvement. Within this study atmospheric particles of different size classes (2.5 to 80 μm) were investigated before, during, and after the Olympic Games period in order to observe and assess the success of short-term measures to mitigate extreme urban aerosol pollution and also to investigate, which particle size classes were reduced most effectively. Furthermore, black carbon (BC) concentrations in fine particles (PM(2.5)) during the source control period were compared to those of the previous years in order to investigate the decrease of combustion-derived aerosols. It is shown that besides the implemented mitigation measures precipitation decisively contributed to a considerable decrease of particulate air pollution in Beijing compared to the respective concentrations during the time directly before and after the Olympic Games, and also compared to average August concentrations during the previous years and the following year 2009. Particles of the fine fraction of the coarse mode (2.5 to 5 μm), which have a residence time in the order of several days and which, therefore, are typically transported over long distances from outside of Beijing, were less efficiently reduced than coarser particles. This indicates that long-range transport of atmospheric particles is difficult to control and that presumably the established mitigation area was not large enough to also reduce the fine fraction of the coarse mode more efficiently. Furthermore, the study showed that coarse geogenic particles, which originated to a high percentage from construction sites and resuspension processes due to traffic seemed to be reduced most efficiently during the Olympic Games period. PMID:22035559

  9. Optimization of probiotic lactobacillus casei ATCC 334 production using date powder as carbon source

    Directory of Open Access Journals (Sweden)

    Shahravy A.

    2012-01-01

    Full Text Available This study was conducted to optimize culture conditions for economic production of a probiotic bacterium, Lactobacillus casei ATCC 334, in which palm date powder was applied for the first time as a low-cost main carbon source. The effect of eleven factors on bacterial growth was investigated using the Taguchi experimental design, and three factors including palm date powder, tryptone and agitation rate were found to be the most significant parameters. The optimum conditions including date powder concentration, 38 g/L; tryptone concentration, 30 g/L; and an agitation rate of 320 rpm were determined by response surface methodology of Box-Behnken. A third-order polynomial model was suggested to predict the design space following which the predicted values were validated experimentally. The maximum log value of the viable cells in the optimized alternative medium was 9.97 at 24 h of incubation which was comparable to that obtained in the complex and expensive MRS medium (10.06.

  10. Influence of various carbohydrate sources on postprandial glucose, insulin and NEFA concentrations in obese cats.

    Science.gov (United States)

    Mori, A; Ueda, K; Lee, P; Oda, H; Ishioka, K; Sako, T

    2016-01-01

    Carbohydrate is an important source of energy, which can significantly affect postprandial blood glucose and insulin levels in cats. In healthy animals, this is not a big concern; however, in obese and diabetic animals, this is an important detail. In the present study, the impact of four different carbohydrate sources (glucose, maltose, corn starch, and trehalose) on short-term post-prandial serum glucose, insulin, and non-esterified fatty acid (NEFA) concentrations was investigated with four obese cats. Each of the carbohydrate sources was added to a commercial wet food diet for feeding the animals. A significant difference was observed in postprandial glucose, insulin, and NEFA area under the curve (AUC) values between each carbohydrate source in obese cats. Furthermore, glucose and maltose induced the highest postprandial glucose and insulin AUC values, whereas trehalose induced the lowest postprandial glucose and insulin AUC value amongst all carbohydrate sources, respectively, in obese cats. However, trehalose has a higher risk of inducing side effects, such as diarrhea, as compared to other carbohydrate sources. As such, different carbohydrate sources appear to have a very significant impact on post-prandial glycemia and subsequent insulin requirement levels in obese cats. These results might be useful when selecting a prescription diet for obese or diabetic cats. In addition, maltose appears to be capable of inducing experimentally evoked postprandial hyperglycemia in obese cats, which may serve as a good tool for use to check the impact and effectiveness of newly developed oral hypoglycemic drugs or supplements for cats in future experiments. PMID:27487514

  11. Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

    Directory of Open Access Journals (Sweden)

    R. M. Healy

    2012-02-01

    Full Text Available An Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS was deployed to investigate the size-resolved chemical composition of single particles at an urban background site in Paris, France, as part of the MEGAPOLI winter campaign in January/February 2010. ATOFMS particle counts were scaled to match coincident Twin Differential Mobility Particle Sizer (TDMPS data in order to generate hourly size-resolved mass concentrations for the single particle classes observed. The total scaled ATOFMS particle mass concentration in the size range 150–1067 nm was found to agree very well with the sum of concurrent High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS and Multi-Angle Absorption Photometer (MAAP mass concentration measurements of organic carbon (OC, inorganic ions and black carbon (BC (R2 = 0.91. Clustering analysis of the ATOFMS single particle mass spectra allowed the separation of elemental carbon (EC particles into four classes: (i EC attributed to biomass burning (ECbiomass, (ii EC attributed to traffic (ECtraffic, (iii EC internally mixed with OC and ammonium sulfate (ECOCSOx, and (iv EC internally mixed with OC and ammonium nitrate (ECOCNOx. Average hourly mass concentrations for EC-containing particles detected by the ATOFMS were found to agree reasonably well with semi-continuous quantitative thermal/optical EC and optical BC measurements (r2 = 0.61 and 0.65–0.68 respectively, n = 552. The EC particle mass assigned to fossil fuel and biomass burning sources also agreed reasonably well with BC mass fractions assigned to the same sources using seven-wavelength aethalometer data (r2 = 0.60 and 0.48, respectively, n = 568. Agreement between the ATOFMS and other instrumentation improved noticeably when a period influenced by significantly aged, internally mixed EC particles was removed from the intercomparison. 88% and 12% of EC particle

  12. Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

    Science.gov (United States)

    Healy, R. M.; Sciare, J.; Poulain, L.; Kamili, K.; Merkel, M.; Müller, T.; Wiedensohler, A.; Eckhardt, S.; Stohl, A.; Sarda-Estève, R.; McGillicuddy, E.; O'Connor, I. P.; Sodeau, J. R.; Wenger, J. C.

    2012-02-01

    An Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) was deployed to investigate the size-resolved chemical composition of single particles at an urban background site in Paris, France, as part of the MEGAPOLI winter campaign in January/February 2010. ATOFMS particle counts were scaled to match coincident Twin Differential Mobility Particle Sizer (TDMPS) data in order to generate hourly size-resolved mass concentrations for the single particle classes observed. The total scaled ATOFMS particle mass concentration in the size range 150-1067 nm was found to agree very well with the sum of concurrent High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and Multi-Angle Absorption Photometer (MAAP) mass concentration measurements of organic carbon (OC), inorganic ions and black carbon (BC) (R2 = 0.91). Clustering analysis of the ATOFMS single particle mass spectra allowed the separation of elemental carbon (EC) particles into four classes: (i) EC attributed to biomass burning (ECbiomass), (ii) EC attributed to traffic (ECtraffic), (iii) EC internally mixed with OC and ammonium sulfate (ECOCSOx), and (iv) EC internally mixed with OC and ammonium nitrate (ECOCNOx). Average hourly mass concentrations for EC-containing particles detected by the ATOFMS were found to agree reasonably well with semi-continuous quantitative thermal/optical EC and optical BC measurements (r2 = 0.61 and 0.65-0.68 respectively, n = 552). The EC particle mass assigned to fossil fuel and biomass burning sources also agreed reasonably well with BC mass fractions assigned to the same sources using seven-wavelength aethalometer data (r2 = 0.60 and 0.48, respectively, n = 568). Agreement between the ATOFMS and other instrumentation improved noticeably when a period influenced by significantly aged, internally mixed EC particles was removed from the intercomparison. 88% and 12% of EC particle mass was apportioned to fossil fuel and biomass burning respectively using the ATOFMS data

  13. Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

    Directory of Open Access Journals (Sweden)

    R. M. Healy

    2011-11-01

    Full Text Available An Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS was deployed to investigate the size-resolved chemical composition of single particles at an urban background site in Paris, France, as part of the MEGAPOLI winter campaign in January/February 2010. ATOFMS particle counts were scaled to match coincident Twin Differential Mobility Particle Sizer (TDMPS data in order to generate hourly size-resolved mass concentrations for the single particle classes observed. The total scaled ATOFMS particle mass concentration in the size range 150–1067 nm was found to agree very well with the sum of concurrent High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS and Multi-Angle Absorption Photometer (MAAP mass concentration measurements of organic carbon (OC, inorganic ions and black carbon (BC (R2 = 0.91. Clustering analysis of the ATOFMS single particle mass spectra allowed the separation of elemental carbon (EC particles into four classes: (i EC attributed to biomass burning (ECbiomass, (ii EC attributed to traffic (ECtraffic, (iii EC internally mixed with OC and ammonium sulfate (ECOCSOx, and (iv EC internally mixed with OC and ammonium nitrate (ECOCNOx. Average hourly mass concentrations for EC-containing particles detected by the ATOFMS were found to agree reasonably well with semi-continuous quantitative thermal/optical EC and optical BC measurements (r2 = 0.61 and 0.65–0.68, respectively, n = 552. The EC particle mass assigned to fossil fuel and biomass burning sources also agreed reasonably well with BC mass fractions assigned to the same sources using seven-wavelength aethalometer data (r2 = 0.60 and 0.48, respectively, n = 568. Agreement between the ATOFMS and other instrumentation improved noticeably when a period influenced by significantly aged, internally mixed EC particles was removed from the intercomparison. 88 % and 12 % of EC

  14. Effects of elevated carbon dioxide and sucrose concentrations on Arabidopsis thaliana root architecture and anatomy

    Energy Technology Data Exchange (ETDEWEB)

    Lee-Ho, E.; Walton, L.J.; Reid, D.M.; Yeung, E.C.; Kurepin, L.V. [Calgary Univ., AB (Canada). Dept. of Biology

    2007-03-15

    Plant root growth is known to be influenced by higher levels of atmospheric carbon dioxide (CO{sub 2}). Roots of some species grown in hydroponics under elevated CO{sub 2} concentrations may be more competitive sinks for photosynthetic assimilates than roots grown under lower CO{sub 2} conditions. Root branching patterns may also be influenced by elevated CO{sub 2} concentrations. Studies have also shown that factors such as soil compaction, salinity and the availability of nitrate, phosphorous, oxygen and water also influence root growth, and the effects of higher CO{sub 2} on roots can be confounded by such environmental factors. This study evaluated the effects of elevated carbon dioxide and sucrose concentrations on Arabidopsis thaliana root growth, morphology, and architecture. Both ambient and elevated CO{sub 2} levels were used along with various sucrose concentrations. The study revealed that A. thaliana plants grown on a phytagar medium in small chambers with elevated CO{sub 2} had longer roots, more lateral root growth than plants grown in ambient CO{sub 2}. Roots in elevated CO{sub 2} were found to have wider root diameters, and more secondary growth. The addition of sucrose to the media closely resembled the effects of elevated CO{sub 2}. In addition, the increase in sucrose concentration had a bigger effect on root morphology under ambient, than elevated CO{sub 2}. Therefore, both elevated CO{sub 2} and increased sucrose concentrations promote root growth by increasing their number, length, and diameter. The dichotomy branching index (DBI) also dropped resulting in a more dichotomous branching pattern. 34 refs., 5 figs.

  15. Losers and winners in coral reefs acclimatized to elevated carbon dioxide concentrations

    Science.gov (United States)

    Fabricius, Katharina E.; Langdon, Chris; Uthicke, Sven; Humphrey, Craig; Noonan, Sam; de'Ath, Glenn; Okazaki, Remy; Muehllehner, Nancy; Glas, Martin S.; Lough, Janice M.

    2011-06-01

    Experiments have shown that ocean acidification due to rising atmospheric carbon dioxide concentrations has deleterious effects on the performance of many marine organisms. However, few empirical or modelling studies have addressed the long-term consequences of ocean acidification for marine ecosystems. Here we show that as pH declines from 8.1 to 7.8 (the change expected if atmospheric carbon dioxide concentrations increase from 390 to 750ppm, consistent with some scenarios for the end of this century) some organisms benefit, but many more lose out. We investigated coral reefs, seagrasses and sediments that are acclimatized to low pH at three cool and shallow volcanic carbon dioxide seeps in Papua New Guinea. At reduced pH, we observed reductions in coral diversity, recruitment and abundances of structurally complex framework builders, and shifts in competitive interactions between taxa. However, coral cover remained constant between pH 8.1 and ~7.8, because massive Porites corals established dominance over structural corals, despite low rates of calcification. Reef development ceased below pH 7.7. Our empirical data from this unique field setting confirm model predictions that ocean acidification, together with temperature stress, will probably lead to severely reduced diversity, structural complexity and resilience of Indo-Pacific coral reefs within this century.

  16. Mesozoic black shales, source mixing and carbon isotopes

    Science.gov (United States)

    Suan, Guillaume

    2016-04-01

    Over the last decades, considerable attention has been devoted to the paleoenvironmental and biogeochemical significance of Mesozoic black shales. Black shale-bearing successions indeed often display marked changes in the organic carbon isotope composition (δ13Corg), which have been commonly interpreted as evidence for dramatic perturbations of global carbon budgets and CO2 levels. Arguably the majority of these studies have discarded some more "local" explanations when interpreting δ13Corg profiles, most often because comparable profiles occur on geographically large and distant areas. Based on newly acquired data and selected examples from the literature, I will show that the changing contribution of organic components with distinct δ13C signatures exerts a major but overlooked influence of Mesozoic δ13Corg profiles. Such a bias occurs across a wide spectrum of sedimentological settings and ages, as shown by the good correlation between δ13Corg values and proxies of kerogen proportions (such as rock-eval, biomarker, palynofacies and palynological data) recorded in Mesozoic marginal to deep marine successions of Triassic, Jurassic and Cretaceous age. In most of these successions, labile, 12C-enriched amorphous organic matter of marine origin dominates strata deposited under anoxic conditions, while oxidation-resistant, 13C-rich terrestrial particles dominate strata deposited under well-oxygenated conditions. This influence is further illustrated by weathering profiles of Toarcian (Lower Jurassic) black shales from France, where weathered areas dominated by refractory organic matter show dramatic 13C-enrichment (and decreased total organic carbon and pyrite contents) compared to non-weathered portions of the same horizon. The implications of these results for chemostratigraphic correlations and pCO2 reconstructions of Mesozoic will be discussed, as well as strategies to overcome this major bias.

  17. A one-step single source route to carbon nanotubes

    Indian Academy of Sciences (India)

    Tao Cheng; Zhiyong Fang; Guifu Zou; Qixiu Hu; Biao Hu; Xiaozhi Yang; Youjin Zhang

    2006-12-01

    Carbon nanotubes (CNTs) have been synthesized via directly pyrolyzing ferrocene in the autoclave. The nanotubes with several micrometers in length have outer and inner diameters in the range of 40–100 nm and 20–40 nm, respectively. An yield of ∼70% of CNTs can be obtained without any accessorial solvents and catalysts. Experimental results showed that a temperature higher than 600°C in conjunction with proper pressure was favourable for achievement of the nanotubes. The growth mechanism of CNTs was also discussed.

  18. Estimation of local concentration from measurements of stochastic adsorption dynamics using carbon nanotube-based sensors

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Hong; Lee, Jay H. [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Braatz, Richard D. [Massachusetts Institute of Technology (MIT), Cambridge (United States)

    2016-01-15

    This paper proposes a maximum likelihood estimation (MLE) method for estimating time varying local concentration of the target molecule proximate to the sensor from the time profile of monomolecular adsorption and desorption on the surface of the sensor at nanoscale. Recently, several carbon nanotube sensors have been developed that can selectively detect target molecules at a trace concentration level. These sensors use light intensity changes mediated by adsorption or desorption phenomena on their surfaces. The molecular events occurring at trace concentration levels are inherently stochastic, posing a challenge for optimal estimation. The stochastic behavior is modeled by the chemical master equation (CME), composed of a set of ordinary differential equations describing the time evolution of probabilities for the possible adsorption states. Given the significant stochastic nature of the underlying phenomena, rigorous stochastic estimation based on the CME should lead to an improved accuracy over than deterministic estimation formulated based on the continuum model. Motivated by this expectation, we formulate the MLE based on an analytical solution of the relevant CME, both for the constant and the time-varying local concentrations, with the objective of estimating the analyte concentration field in real time from the adsorption readings of the sensor array. The performances of the MLE and the deterministic least squares are compared using data generated by kinetic Monte Carlo (KMC) simulations of the stochastic process. Some future challenges are described for estimating and controlling the concentration field in a distributed domain using the sensor technology.

  19. The effect of nitrogen source on photosynthesis of carob at high CO[sub 2] concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, C.; Martins-Loucao, M.A. (Depto. de Biologia Vegetal, Faculdade de Ciencias de Lisboa, Lisboa (Portugal)); Lips, S.H. (Desert Agrobiology Center, J. Blaustein Inst. for Desert Research, Gen-Gurion Univ. of the Negev, Sede Boqer (Israel))

    1993-01-01

    Carob seedlings (Ceratonia siliqua L. cv. Mulata), fed with nitrate or ammonium, were grown in growth chambers containing two levels of CO[sub 2] (360 or 800 [mu]l l[sup -1]), three root temperatures (15, 20 or 25 deg. C), and the same shoot temperature (20/24 deg. C, night/day temperature). The response of the plants to CO[sub 2] enrichment was affected by environmental factors such as the type of inorganic nitrogen in the medium and root temperature. Increasing root temperature enhanced photosynthesis rate more in the presence of nitrate than in the presence of ammonium. Differences in photosynthetic products were also observed between nitrate- and ammonium-fed carob seedlings. Nitrate-grown plants showed an enhanced content of sucrose, while ammonium led to enhanced storage of starch. Increase in root temperature caused an increase in dry mass of the plants of similar proportions in both nitrogen sources. The enhancement of the rates of photosynthesis by CO[sub 2] enrichment was proportionally much larger than the resulting increases in dry mass production when nitrate was the nitrogen source. Ammonium was the preferred nitrogen source for carob at both ambient and high CO[sub 2] concentrations. The level of photosynthesis of a plant is limited not only by atmospheric CO[sub 2] concentration but also by the nutritional and environmental conditions of the root. (au) (17 refs.)

  20. Carbon sources in the Beaufort Sea revealed by molecular lipid biomarkers and compound specific isotope analysis

    Directory of Open Access Journals (Sweden)

    I. Tolosa

    2012-10-01

    Full Text Available Molecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids and compound specific isotope analysis of suspended particulate organic matter (SPM and surface sediments of the Mackenzie Shelf and slope (Southeast Beaufort Sea, Arctic Ocean, were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C3 terrestrial plants, bacterial and zooplankton material in the sedimentary organic matter (OM.

    Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C3 terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and < 1%, respectively. In marine SPM from the Mackenzie slope, the major contributions were fresh and detrital algal components (> 80% with a minor contribution of fossil and C3 terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C3 terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60–75% whereas those from the slope contained the highest proportion of fossil (40% and C3 terrestrial plant material (10%. Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the

  1. Concentrations of fine, ultrafine, and black carbon particles in auto-rickshaws in New Delhi, India

    Science.gov (United States)

    Apte, Joshua, S.; Kirchstetter, Thomas W.; Reich, Alexander, H.; Deshpande, Shyam J.; Kaushik, Geetanjali; Chel, Arvind; Marshall, Julian D.; Nazaroff, William W.

    2011-08-01

    Concentrations of air pollutants from vehicles are elevated along roadways, indicating that human exposure in transportation microenvironments may not be adequately characterized by centrally located monitors. We report results from ˜180 h of real-time measurements of fine particle and black carbon mass concentration (PM 2.5, BC) and ultrafine particle number concentration (PN) inside a common vehicle, the auto-rickshaw, in New Delhi, India. Measured exposure concentrations are much higher in this study (geometric mean for ˜60 trip-averaged concentrations: 190 μg m -3 PM 2.5, 42 μg m -3 BC, 280 × 10 3 particles cm -3; GSD ˜1.3 for all three pollutants) than reported for transportation microenvironments in other megacities. In-vehicle concentrations exceeded simultaneously measured ambient levels by 1.5× for PM 2.5, 3.6× for BC, and 8.4× for PN. Short-duration peak concentrations (averaging time: 10 s), attributable to exhaust plumes of nearby vehicles, were greater than 300 μg m -3 for PM 2.5, 85 μg m -3 for BC, and 650 × 10 3 particles cm -3 for PN. The incremental increase of within-vehicle concentration above ambient levels—which we attribute to in- and near-roadway emission sources—accounted for 30%, 68% and 86% of time-averaged in-vehicle PM 2.5, BC and PN concentrations, respectively. Based on these results, we estimate that one's exposure during a daily commute by auto-rickshaw in Delhi is as least as large as full-day exposures experienced by urban residents of many high-income countries. This study illuminates an environmental health concern that may be common in many populous, low-income cities.

  2. Using Ozone Lidar to Investigate Sources of High Ozone Concentrations in the Western United States

    Directory of Open Access Journals (Sweden)

    Senff C. J.

    2016-01-01

    Full Text Available We have used NOAA’s Tunable Optical Profiler for Aerosol and oZone (TOPAZ ozone lidar to investigate the sources of high surface ozone concentrations in two different regions of the western United States (US: the Uintah Basin in northeast Utah and Clark County in southern Nevada, which includes the city of Las Vegas. The Uintah Basin is a booming oil and gas producing region that often suffers from very high wintertime ozone concentrations. Clark County experiences violations of the US ozone standard primarily in spring and early summer despite a lack of any major local pollution sources. TOPAZ lidar observations, in conjunction with surface in situ measurements and model results, provided strong evidence that the high wintertime ozone concentrations in the Uintah Basin are primarily driven by local emissions associated with oil and gas exploration, whereas the Clark County ozone exceedances are often caused by ozone-rich air that is transported from the lower stratosphere all the way down to the earth’s surface.

  3. Polycyclic aromatic hydrocarbons in urban air : concentration levels and patterns and source analysis in Nairobi, Kenya

    Energy Technology Data Exchange (ETDEWEB)

    Muthini, M.; Yoshimichi, H.; Yutaka, K.; Shigeki, M. [Yokohama National Univ., Yokohama (Japan). Graduate School of Environment and Information Sciences

    2005-07-01

    Polycyclic aromatic hydrocarbons (PAHs) present in the environment are often the result of incomplete combustion processes. This paper reported concentration levels and patterns of high molecular weight PAHs in Nairobi, Kenya. Daily air samples for 30 different PAHs were collected at residential, industrial and business sites within the city. Samples were then extracted using deuterated PAH with an automated Soxhlet device. Gas chromatography and mass spectrometry (GC-MS) with a capillary column was used to analyze the extracts using a selected ion monitoring (SIM) mode. Statistical analyses were then performed. PAH concentration levels were reported for average, median, standard deviation, range, and Pearson's correlation coefficients. Data were then analyzed for sources using a principal component analysis (PCA) technique and isomer ratio analysis. Nonparametric testing was then conducted to detect inherent differences in PAH concentration data obtained from the different sites. Results showed that pyrene was the most abundant PAH. Carcinogenic PAHs were higher in high-traffic areas. The correlation coefficient between coronene and benzo(ghi)pyrene was high. The PAH isomer ratio analysis demonstrated that PAHs in Nairobi are the product of traffic emissions and oil combustion. Results also showed that PAH profiles were not well separated. It was concluded that source distinction methods must be improved in order to better evaluate PAH emissions in the city. 9 refs., 2 tabs., 1 fig.

  4. Effect of Dietary Inulin Source on Piglet Performance, Immunoglobulin Concentration, and Plasma Lipid Profile

    Directory of Open Access Journals (Sweden)

    Grela Eugeniusz R.

    2014-10-01

    Full Text Available The aim of the study was to evaluate the effect of an inulin source (aqueous or aqueous-alcoholic extract, dried chicory root, or dried Jerusalem artichoke tubers on piglet performance, plasma lipid profile, and immunoglobulin concentration. The study was conducted on 534 piglets (44 litters allocated to five nutritional groups: group I (control - fed basal diet, groups II and III receiving basal diet supplemented with 2% of inulin (aqueous and aqueous-alcoholic extract respectively, and groups IV and V -4% additive of dried artichoke or dried chicory respectively. During the trial, piglets’ body weight, feed intake, diarrhoea incidence, and mortality were controlled. Blood samples were collected twice from six animals of each group. In blood plasma, indices of lipid profile and concentrations of IgA, IgG and IgM were measured. The addition of inulin, regardless of its form (extracts or dried plants, significantly improved the rearing indices. In piglets of groups III, IV and V a significant improvement of daily weight gains and feed efficiency was noted. Inulin showed hypolipidemic activity (lowered total cholesterol level and stimulated piglet immune system manifested by elevated IgA and IgG concentrations. Irrespective of the inulin source, a lower mortality rate resulting from the improvement of animal health was noted in all experimental groups.

  5. Coupling meteorology, metal concentrations, and Pb isotopes for source attribution in archived precipitation samples.

    Science.gov (United States)

    Graney, Joseph R; Landis, Matthew S

    2013-03-15

    A technique that couples lead (Pb) isotopes and multi-element concentrations with meteorological analysis was used to assess source contributions to precipitation samples at the Bondville, Illinois USA National Trends Network (NTN) site. Precipitation samples collected over a 16month period (July 1994-October 1995) at Bondville were parsed into six unique meteorological flow regimes using a minimum variance clustering technique on back trajectory endpoints. Pb isotope ratios and multi-element concentrations were measured using high resolution inductively coupled plasma-sector field mass spectrometry (ICP-SFMS) on the archived precipitation samples. Bondville is located in central Illinois, ~250km downwind from smelters in southeast Missouri. The Mississippi Valley Type ore deposits in Missouri provided a unique multi-element and Pb isotope fingerprint for smelter emissions which could be contrasted to industrial emissions from the Chicago and Indianapolis urban areas (~125km north and east, of Bondville respectively) and regional emissions from electric utility facilities. Differences in Pb isotopes and element concentrations in precipitation corresponded to flow regime. Industrial sources from urban areas, and thorogenic Pb from coal use, could be differentiated from smelter emissions from Missouri by coupling Pb isotopes with variations in element ratios and relative mass factors. Using a three endmember mixing model based on Pb isotope ratio differences, industrial processes in urban airsheds contributed 56±19%, smelters in southeast Missouri 26±13%, and coal combustion 18±7%, of the Pb in precipitation collected in Bondville in the mid-1990s.

  6. Using Ozone Lidar to Investigate Sources of High Ozone Concentrations in the Western United States

    Science.gov (United States)

    Senff, C. J.; Langford, A. O.; Alvarez, R. J.; Brewer, Wm. A.; Banta, R. M.; Marchbanks, R. D.; Sandberg, S. P.; Weickmann, A. M.; Holloway, J. S.; Williams, E. J.

    2016-06-01

    We have used NOAA's Tunable Optical Profiler for Aerosol and oZone (TOPAZ) ozone lidar to investigate the sources of high surface ozone concentrations in two different regions of the western United States (US): the Uintah Basin in northeast Utah and Clark County in southern Nevada, which includes the city of Las Vegas. The Uintah Basin is a booming oil and gas producing region that often suffers from very high wintertime ozone concentrations. Clark County experiences violations of the US ozone standard primarily in spring and early summer despite a lack of any major local pollution sources. TOPAZ lidar observations, in conjunction with surface in situ measurements and model results, provided strong evidence that the high wintertime ozone concentrations in the Uintah Basin are primarily driven by local emissions associated with oil and gas exploration, whereas the Clark County ozone exceedances are often caused by ozone-rich air that is transported from the lower stratosphere all the way down to the earth's surface.

  7. A series of tufted carbon fiber cathodes designed for different high power microwave sources

    Science.gov (United States)

    Liu, Lie; Li, Limin; Zhang, Jun; Zhang, Xiaoping; Wen, Jianchun; Liu, Yonggui

    2008-06-01

    We report the fabrication technique of tufted carbon fiber cathodes for different microwave sources. Three carbon fiber cathodes were constructed, including a planar cathode, an annular cathode, and a cylindrical cathode for radial emission. Experimental investigations on these cathodes were performed in a reflex triode virtual cathode oscillator (vircator), a backward wave oscillator (BWO), and a magnetically insulated transmission line oscillator (MILO), respectively. The pulse duration of microwave emission from the reflex triode vircator was lengthened by using the planar carbon fiber cathode. In the BWO with the annular carbon fiber cathode, the uniform electron beam with a kA /cm2 current density was observed. In addition, carbon fiber has great promise as field emitter for MILOs. These results show that the carbon fiber cathodes can be utilized for electron emission in high power diodes with different structures.

  8. Understanding and modelling the variability in Dissolved Organic Carbon concentrations in catchment drainage

    Science.gov (United States)

    Coleman, Martin; Waldron, Susan; Scott, Marian; Drew, Simon

    2013-04-01

    Our knowledge of dynamic natural habitats could be improved through the deployment of automated sensor technology. Dissolved organic carbon concentrations, [DOC], are of interest to water companies as purification removes this pool and currently in environmental science, due in part to rising DOC levels and also as respiration of this C pool can lead to an increased CO2 efflux. Manual sampling of catchment drainage systems has revealed seasonal patterns in DOC (Williams, P.J.L., 1995) and that hydrological events export most DOC(Raymond, P.A. and J.E. Saiers, 2010). However, manual sampling precludes detailed characterisation of the dynamic fluctuation of DOC over shorter but important time periods e.g. immediately prior to an event; the transition from base flow to a surface run-off dominated system as surface flow pathways defrost. Such insight is only gained through deployment of continuous-monitoring equipment. Since autumn 2010 we have deployed an S::CAN Spectrolyser (which from absorbance gives a measurement of [DOC]) in a 7.5 kilometre squared peaty catchment draining Europe's largest windfarm, Whitelee. Since autumn 2011, we have an almost complete time series of [DOC] every 30. Here [DOC] has ranged from 12.2 to 58.4 mg/l C and during event flow DOC had a maximum variation of 23.5 mg/l within a single day. Simultaneously with the Spectrolyser, we have logged stage height, pH and conductivity using an In-Situ Inc MD Troll 9000. Generally there is an inverse relationship between [DOC] and both pH and conductivity, but a positive relationship (albeit with seasonal differences) with [DOC] and stage height, from which we can infer hydrological changes in the source of the DOC. Here, in addition to presenting the time series of the data, and a more accurate export budget estimate, I will explore statistical methods for the handling of large datasets. Trends in the data of such large and dynamic data sets are challenging to model. Simple relationships with stage

  9. Immobilized Tannin from Sanseviera trifasciata on Carbon as Adsorbent For Iron(II in Polluted Water Source

    Directory of Open Access Journals (Sweden)

    Irfan Hanafi Arif

    2016-03-01

    Full Text Available The organic-agricultural waste resulted from local farmer or community gardening recently paid public attention. The presence and easily grown of “Lidah Mertua” or Sanseviera trifasciata being focused on potency investigation for its prospecting application. It was reported contain some phenolic and also tannin extracted from aqueous solvents. This paper revealed recent investigation applying of its isolated tannin from leave part to modifying of activated carbon. The previous report published that carbon were able to adsorb some toxic heavy metals. However, it has some limitation including lower capacity adsorption. Impregnated or immobilized the tannin-isolated from S. trifasciata leaves was able to modify the carbon functionality, physical appearance, pores size, and it adsorption capacity. Both Langmuir and Freundlich adsorption mechanism model also disclosed the developed adsorbent mechanism of iron(II adsorption on the adsorbent tannin-immobolized on carbon. The real test using community well drilling water source also gave important finding on the concentration of iron(II contained on water source.

  10. Determination of Concentration Dependent Diffusion Coefficients of Carbon in Expanded Austenite

    DEFF Research Database (Denmark)

    Hummelshøj, Thomas Strabo; Christiansen, Thomas; Somers, Marcel A. J.

    2008-01-01

    Abstract. In the present paper various experimental procedures to experimentally determine the concentration dependent diffusion coefficient of carbon in expanded austenite are evaluated. To this end thermogravimetric carburization was simulated for various experimental conditions and the evaluated...... composition dependent diffusivity of carbon derived from the simulated experiments was compared with the input data. The most promising procedure for an accurate determination is shown to be stepwise gaseous carburizing of thin foils in a gaseous atmosphere; the finer the stepsize, the more accurate...... the approximation of the diffusivity. Thermogravimetry was applied to continuously monitor the weight change of thin foils of AISI 316 during carburizing in CO-H2 gas mixtures for one of the simulated experimental procedures....

  11. Remediation of nitrate-contaminated wastewater using denitrification biofilters with straws of ornamental flowers added as carbon source.

    Science.gov (United States)

    Chang, Junjun; Ma, Luyao; Zhou, Yuanyang; Zhang, Shenghua; Wang, Weilu

    2016-01-01

    Straws of four ornamental flowers (carnation, rose, lily, and violet) were added into denitrification biofilters using gravel as matrix through vertically installed perforated polyvinylchloride pipes to provide organic carbon for the treatment of nitrate-contaminated wastewater operating in batch mode. Removal efficiencies of nitrate and phosphate, as well as temporal variations of nitrogen and carbon during batches 10 and 19, were investigated and assessed. Nitrate removal was efficiently enhanced by the addition of flower straws, but decreased gradually as the organic substances were consumed. Phosphate removal was also improved, although this very limited. High nitrate removal rates were achieved during the initial 12 h in the two batches each lasting for 3 days, along with the depletion of influent dissolved oxygen due to aerobic degradation of the organic compounds. NO2(-)-N of 0.01-2.83 mg/L and NH4(+)-N of 0.02-1.69 mg/L were formed and both positively correlated to the nitrate reduced. Inorganic carbon (IC) concentrations increased during the batches and varied conversely with the nitrate contents, and could be indicative of nitrate removal due to the highly significant positive correlation between NO3(-)-N removed and IC concentration (r(2) = 0.881, p biofilter to treat nitrate-contaminated wastewater, although further optimization of carbon source addition is still required.

  12. Long-term aerosol measurements in Gran Canaria, Canary Islands: Particle concentration, sources and elemental composition

    Science.gov (United States)

    Gelado-Caballero, MaríA. D.; López-GarcíA, Patricia; Prieto, Sandra; Patey, Matthew D.; Collado, Cayetano; HéRnáNdez-Brito, José J.

    2012-02-01

    There are very few sets of long-term measurements of aerosol concentrations over the North Atlantic Ocean, yet such data is invaluable in quantifying atmospheric dust inputs to this ocean region. We present an 8-year record of total suspended particles (TSP) collected at three stations on Gran Canaria Island, Spain (Taliarte at sea level, Tafira 269 m above sea level (a.s.l.) and Pico de la Gorra 1930 m a.s.l.). Using wet and dry deposition measurements, the mean dust flux was calculated at 42.3 mg m-2 d-1. Air mass back trajectories (HYSPLIT, NOAA) suggested that the Sahara desert is the major source of African dust (dominant during 32-50% of days), while the Sahel desert was the major source only 2-10% of the time (maximum in summer). Elemental composition ratios of African samples indicate that, despite the homogeneity of the dust in collected samples, some signatures of the bedrocks can still be detected. Differences were found for the Sahel, Central Sahara and North of Sahara regions in Ti/Al, Mg/Al and Ca/Al ratios, respectively. Elements often associated with pollution (Pb, Cd, Ni, Zn) appeared to share a common origin, while Cu may have a predominantly local source, as suggested by a decrease in the enrichment factor (EF) of Cu during dust events. The inter-annual variability of dust concentrations is investigated in this work. During winter, African dust concentration measurements at the Pico de la Gorra station were found to correlate with the North Atlantic Oscillation (NAO) index.

  13. Association of drinking-water source and use characteristics with urinary antimony concentrations.

    Science.gov (United States)

    Makris, Konstantinos C; Andra, Syam S; Herrick, Lisa; Christophi, Costas A; Snyder, Shane A; Hauser, Russ

    2013-03-01

    Environmental factors, such as storage time, frequency of bottle reuse and temperature, have been shown to facilitate antimony (Sb) leaching from water- and food-packaging materials. The globally escalating consumption of water packaged in Sb-containing bottles, such as that of polyethylene terephthalate (PET), could increase human daily Sb doses. This study set out to investigate the relationship between drinking-water source, use characteristics, and urinary Sb concentrations (U-Sb) accompanied with survey responses of a healthy (n=35) Cypriot participant pool. One spot urine sample was collected during administration of questionnaire, while a second spot urine sample was collected from the same individual about 7 days later. Urinary and water Sb concentrations were measured with an inductively coupled plasma mass spectrometer. Survey responses showed that bottled water summed over various volumes and plastic types, such as polycarbonate and PET contributed to an average 61% of daily water consumption. Water sources such as tap, mobile stations (explained in a following section), and well water contributed to 24%, 14%, and 2% of an individual's daily water consumption pattern, respectively. Average daily potable water use of both bottled and tap water by individuals consisted of 65% drinking-water, while the remaining 35% was water used for preparing cold and hot beverages, such as, tea, coffee, and juices. A significant (P=0.02) association between per capita water consumption from PET bottles and urinary creatinine-unadjusted concentrations was observed, but this relationship did not remain after inclusion of covariates in a multivariate regression model. In the creatinine-adjusted regression model, only gender (female) was a significant (P<0.01) predictor of U-Sb, after adjusting for several covariates. It is proposed that consumption data collection on various water uses and sources among individuals could perhaps decrease the uncertainty associated with

  14. The potential of non-carbon energy sources in developing countries - The case of the PRC

    International Nuclear Information System (INIS)

    While developing countries presently account for a small share of the world's carbon emissions, in coming years, the quantity of energy-related CO2 generated by developing nations will surpass the amount produced by industrialized countries. In response to this trend, an increasing amount o attention has been paid to the prospect of reducing emissions in developing countries by exploiting non-carbon energy resources. To date, however, financial constraints have limited the development of non-carbon alternatives; the costs of these sources typically loom far above the costs of conventional forms of energy. Due to its heavy reliance on coal energy, China makes a disproportionately high contribution to global CO2. In 1990, China's energy-related activities consumed 8% of the world's commercial energy, but accounted for 11% of global carbon emissions. While financial constraints will continue to hinder the exploration of non-carbon alternatives, increasing the roles of hydropower, nuclear energy, solar radiation and wind energy could play a major role in curtailing the growth of carbon emissions in the PRC. This paper evaluates the potential for integrating various non-carbon energy sources in China and provides possible strategies for deploying these sources

  15. Evaluation criteria for gas source rocks of marine carbonate in China

    Institute of Scientific and Technical Information of China (English)

    WANG Zhaoyun; ZHAO Wenzhi; WANG Yunpeng

    2005-01-01

    Hydrocarbon generating and expulsion simulation experiments are carried out using samples artifically matched between the acid-dissolved residue of relatively low-maturity limestone and the original sample. This work makes up for the insufficiency of source rock samples with high abundance of organic matters and low maturity in China. The organic carbon content of the 10 prepared samples varies between 0.15 % and 0.74 %. Pyrolysis data and simulation experiment results of hydrocarbon generating and expulsion, which were obtained by a high-temperature and high-pressure open system, indicate that the lower limit of organic carbon content for marine carbonate rock to generate and expel hydrocarbons is 0.23 %-0.31%. In combination with the numerical analysis of organic carbon in marine carbonate rocks from Tarim Basin, Sichuan Basin, Ordos Basin and North China, as well as the contribution of these gas source rocks to the discovered gas pools, we think that the organic carbon criterion for carbonate gas source rocks should be 0.3%.

  16. Influence of carbon source on alpha-amylase production by Aspergillus oryzae

    DEFF Research Database (Denmark)

    Carlsen, Morten; Nielsen, Jens

    2001-01-01

    The influence of the carbon source on a-amylase production by Aspergillus oryzae was quantified in carbon-limited chemostat cultures. The following carbon sources were investigated: maltose, maltodextrin (different chain lengths), glucose, fructose, galactose, sucrose, glycerol, mannitol and acet......The influence of the carbon source on a-amylase production by Aspergillus oryzae was quantified in carbon-limited chemostat cultures. The following carbon sources were investigated: maltose, maltodextrin (different chain lengths), glucose, fructose, galactose, sucrose, glycerol, mannitol...... on sucrose, fructose, glycerol, mannitol and acetate. During growth on acetate there was no production of alpha -amylase, whereas addition of small amounts of glucose resulted in alpha -amylase production. A possible induction by alpha -methyl-D-glucoside during growth on glucose was also investigated......, but this compound was not found to be a better inducer of alpha -amylase production than glucose. The results strongly indicate that besides acting as a repressor via the CreA protein, glucose acts as an inducer....

  17. Year-round probing of soot carbon and secondary organic carbon contributions and sources to the South Asian Atmospheric Brown Cloud using radiocarbon (14C) measurements

    Science.gov (United States)

    Kirillova, Elena; Sheesley, Rebecca J.; Andersson, August; Krusâ, Martin; Safai, P. D.; Budhavant, Krishnakant; Rao, P. S. P.; Praveen, P. S.; Gustafsson, Örjan

    2010-05-01

    South Asia is one region of vital importance for assessing human impact on radiative forcing by atmospheric aerosols. Previous research in the region has indicated that black carbon is a significant component of the regional aerosol load. In contrast, there is more ambiguous information regarding the contribution of secondary organic aerosols (SOA) to the total carbonaceous (TC) aerosol composition. Here we primarily address the SOA component of the South Asian Atmospheric Brown Cloud (ABC) by a combination of measurements of SOA concentrations and the 14C signature of TC. Atmospheric particulate matter was collected during fourteen-month continuous sampling campaigns Jan 2008 - March 2009 at both the Maldives Climate Observatory at Hannimaadho (MCO-H) and at the Sinhagad hilltop sampling site of the Indian Institute of Tropical Meteorology (SIN) in central-western India. The radiocarbon method is an ideal approach to identify fossil sources (14C "dead") compared to biogenic and biomass combustion products (with a contemporary 14C signal). The radiocarbon source apportionment of TC revealed very similar contribution from biogenic/biomass combustion (60-70%) for Indian SIN site and the MCOH receptor regions for much of the year. However, during the summer monsoon season biomass contribution to TC at the Indian Ocean site increases to 70-80%, while it decreases to 40-50% at the Indian site. Source apportionment of a soot carbon (SC) isolate (CTO-375 method; a tracer of black carbon) shows a similar trend. According to preliminary data in summer biomass contribution is higher at the MCOH receptor site (70%) compared to the SIN background site (45%). These unique year-round 14C data will be interpreted in view of the SOA concentration and the varying origin of the air masses.

  18. Organic carbon source and burial during the past one hundred years in Jiaozhou Bay, North China

    Institute of Scientific and Technical Information of China (English)

    LI Xuegang; YUAN Huamao; LI Ning; SONG Jinming

    2008-01-01

    Organic carbon (OC), total nitrogen (TN), and 210Pb in core sediment were measured to quantify the burial of organic carbon and the relative importance of allochthonous and autochthonous contributions during the past one hundred years in Jiaozhou Bay, North China. The core sediment was dated using 210Pb chronology, which is the most promising method for estimation of sedimentation rate on a time scale of 100-150 years. The variation of the burial flux of organic carbon in the past one hundred years can be divided into the following three stages: (1) relatively steady before 1980s; (2) increasing rapidly from the 1980s to a peak in the 1990s, and (3) decreasing from the 1990s to the present. The change is consistent with the amount of solid waste and sewage emptied into the bay. The OC:TN ratio was used to evaluate the source of organic carbon in the Jiaozhou Bay sediment. In the inner bay and bay mouth, the organic carbon was the main contributor from terrestrial sources, whereas only about half of organic carbon was contributed from terrestrial source in the outer bay. In the inner bay, the terrestrial source of organic carbon showed a steady change with an increase in the range of 69%-77% before 1990 to 93% in 2000, and then decreased from 2000 because of the decrease in the terrestrial input. In the bay mouth, the percentage of organic carbon from land reached the highest value with 94% in 1994. In the outer bay, the sediment source maintained steady for the past one hundred years.

  19. Morphological Comparison of U3O8 Ore Concentrates from Canada Key Lake and Namibia Sources

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Daniel S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tandon, Lav [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Martinez, Patrick Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-11

    Uranium ore concentrates from two different sources were examined using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The ore powders are referred to as Namibia (id. no. 90036, LIMS id. no. 18775) and Canada Key Lake (id. no. 90019, LIMS id. no. 18774). Earlier work identified the ores as the U₃O₈ phase of uranium oxide using x-ray diffraction. Both sets of powders were in the form of dark brown to black powder fines. However, the Canada Key Lake concentrates contained larger chunks of material on the millimeter scale that were easily visible to the unaided eye. The powders were mounted for SEM examination by hand dispersing a small amount onto conductive sticky tape. Two types of applicators were used and compared: a fine-tipped spatula and a foam-tipped applicator. The sticky tape was on a standard SEM “tee” mount, which was tapped to remove loose contamination before being inserted into the SEM.

  20. Bisphenol A in Urine of Chinese Young Adults: Concentrations and Sources of Exposure.

    Science.gov (United States)

    Gao, Chongjing; Liu, Liyan; Ma, Wanli; Zhu, Ningzheng; Jiang, Ling; Ren, Nanqi; Li, Yi-Fan; Kannan, Kurunthachalam

    2016-02-01

    Bisphenol A (BPA) is an endocrine disrupting environmental chemical. Urinary concentrations of BPA were measured in samples collected nationwide from Chinese young adults. The geometric mean urinary concentration of BPA in Chinese young adults was 2.23 ng/mL. The estimated daily exposure dose for BPA was 64.8 ng/kg bw/day. Contributions of various BPA sources to exposure in Chinese young adults were estimated. Dietary intake was the primary exposure pathway. The contribution of dietary intake, indoor dust, paper products and personal care products to BPA intake was 72.5 %, 0.74 %, 0.98 %, 0.22 % of the total exposure dose, respectively. This is the first study on the occurrence of BPA in young adults from most provinces and autonomous regions of China. The results can be used to establish a database for BPA exposure assessment for Chinese general population. PMID:26679324

  1. Bisphenol A in Urine of Chinese Young Adults: Concentrations and Sources of Exposure.

    Science.gov (United States)

    Gao, Chongjing; Liu, Liyan; Ma, Wanli; Zhu, Ningzheng; Jiang, Ling; Ren, Nanqi; Li, Yi-Fan; Kannan, Kurunthachalam

    2016-02-01

    Bisphenol A (BPA) is an endocrine disrupting environmental chemical. Urinary concentrations of BPA were measured in samples collected nationwide from Chinese young adults. The geometric mean urinary concentration of BPA in Chinese young adults was 2.23 ng/mL. The estimated daily exposure dose for BPA was 64.8 ng/kg bw/day. Contributions of various BPA sources to exposure in Chinese young adults were estimated. Dietary intake was the primary exposure pathway. The contribution of dietary intake, indoor dust, paper products and personal care products to BPA intake was 72.5 %, 0.74 %, 0.98 %, 0.22 % of the total exposure dose, respectively. This is the first study on the occurrence of BPA in young adults from most provinces and autonomous regions of China. The results can be used to establish a database for BPA exposure assessment for Chinese general population.

  2. Longitudinal dispersion with time-dependent source concentration in semi-infinite aquifer

    Indian Academy of Sciences (India)

    Mritunjay Kumar Singh; Nav Kumar Mahato; Premlata Singh

    2008-12-01

    An analytical solution is obtained to predict the contaminant concentration along unsteady ground-water flow in semi-in finite aquifer. Initially,the aquifer is not supposed to be solute free ,i.e.,aquifer is not clean.A time-dependent source concentration is considered at the origin of the aquifer and at the other end of the aquifer, it is supposed to be zero. The time-dependent forms of unsteady velocities are considered in which one such form ,i.e., sinusoidal form represents the seasonal pattern in a year in tropical regions. The Laplace Transformation Technique (LTT)is used to get an analytical solution and a graphical representation is made through MATLAB.

  3. Effect of fermentation liquid from food waste as a carbon source for enhancing denitrification in wastewater treatment.

    Science.gov (United States)

    Zhang, Yongmei; Wang, Xiaochang C; Cheng, Zhe; Li, Yuyou; Tang, Jialing

    2016-02-01

    Food wastes were used for anaerobic fermentation to prepare carbon sources for enhancing nitrogen removal in wastewater treatment. Under anaerobic conditions without pH adjustment, the fermentation liquid from food wastes (FLFW) with a high organic acid content was produced at room temperature (25 °C) and initial solid concentration of 13%. Using FLFW as the sole carbon source of artificial wastewater for biological treatment by sequence batch operation, maximized denitrification (with a denitrification rate of V(DN) = 12.89 mg/gVSS h and a denitrification potential of P(DN) = 0.174 gN/gCOD) could be achieved at a COD/TN ratio of 6. The readily biodegradable fraction in the FLFW was evaluated as 58.35%. By comparing FLFW with glucose and sodium acetate, two commonly used chemical carbon sources, FLFW showed a denitrification result similar to sodium acetate but much better than glucose in terms of total nitrogen removal, V(DN), P(DN), organic matter consumption rate (V(COD)) and heterotrophy anoxic yield coefficient (Y(H)).

  4. Energy efficiency of growing ram lambs fed concentrate-based diets with different roughage sources.

    Science.gov (United States)

    Galvani, D B; Pires, A V; Susin, I; Gouvêa, V N; Berndt, A; Chagas, L J; Dórea, J R R; Abdalla, A L; Tedeschi, L O

    2014-01-01

    Poor-quality roughages are widely used as fiber sources in concentrate-based diets for ruminants. Because roughage quality is associated with the efficiency of energy use in forage-based diets, the objective of this study was to determine whether differing the roughage source in concentrate-based diets could change the energy requirements of growing lambs. Eighty-four 1/2 Dorper × 1/2 Santa Inês ram lambs (18.0 ± 3.3 kg BW) were individually penned and divided into 2 groups according to primary source of dietary roughage: low-quality roughage (LQR; sugarcane bagasse) or medium-quality roughage (MQR; coastcross hay). Diets were formulated to be isonitrogenous (2.6% N) and to meet 20% of physically effective NDF. After a 10-d ad libitum adaptation period, 7 lambs from each group were randomly selected and slaughtered (baseline). Twenty-one lambs in each diet group were fed ad libitum and slaughtered at 25, 35, or 45 kg BW. The remaining 28 lambs (14 from each diet group) were submitted to 1 of 2 levels of feed restriction: 70% or 50% of the ad libitum intake. Retentions of body fat, N, and energy were determined. Additionally, 6 ram lambs (44.3 ± 5.6 kg BW) were kept in metabolic cages and used in a 6 × 6 Latin square experiment designed to establish the ME content of the 2 diets at the 3 levels of DM intake. There was no effect of intake level on diet ME content, but it was greater in the diet with LQR than in the diet with MQR (3.18 vs. 2.94 Mcal/kg, respectively; P < 0.01). Lambs fed the diet with LQR had greater body fat (g/kg of empty BW) and energy concentrations (kcal/kg of empty BW) because of a larger visceral fat deposition (P < 0.05). Using a low-quality roughage as a primary source of forage in a concentrate-based diet for growing lambs did not change NEm and the efficiency of ME use for maintenance, which averaged 71.6 kcal/kg(0.75) of shrunk BW and 0.63, respectively. On the other hand, the greater nonfibrous carbohydrate content of the diet with

  5. Yield and Mineral Element Concentration of Beetroot in Response to Nutrient Source in Hydroponic Solution

    OpenAIRE

    Egilla, Jonathan N.

    2009-01-01

    The yield and mineral element concentration of beetroot (Beta vulgaris ‘Bulls Blood’) was determined in a closed nutrient-recirculating ‘Nutrient Film Technique’ (NFT) hydroponic experiment. Seedlings were grown and harvested 42 days after transfer into NFT system (DAT), either with a commercial hydroponic fertilizer or a non-hydroponic soluble fertilizer containing in mg liter-1: 108 nitrogen (N) and 12 calcium (Ca) (N1Ca1), or 200 N and 66.7 Ca (N2Ca2), respectively. Nutrient source had no ...

  6. Energy efficiency of growing ram lambs fed concentrate-based diets with different roughage sources.

    Science.gov (United States)

    Galvani, D B; Pires, A V; Susin, I; Gouvêa, V N; Berndt, A; Chagas, L J; Dórea, J R R; Abdalla, A L; Tedeschi, L O

    2014-01-01

    Poor-quality roughages are widely used as fiber sources in concentrate-based diets for ruminants. Because roughage quality is associated with the efficiency of energy use in forage-based diets, the objective of this study was to determine whether differing the roughage source in concentrate-based diets could change the energy requirements of growing lambs. Eighty-four 1/2 Dorper × 1/2 Santa Inês ram lambs (18.0 ± 3.3 kg BW) were individually penned and divided into 2 groups according to primary source of dietary roughage: low-quality roughage (LQR; sugarcane bagasse) or medium-quality roughage (MQR; coastcross hay). Diets were formulated to be isonitrogenous (2.6% N) and to meet 20% of physically effective NDF. After a 10-d ad libitum adaptation period, 7 lambs from each group were randomly selected and slaughtered (baseline). Twenty-one lambs in each diet group were fed ad libitum and slaughtered at 25, 35, or 45 kg BW. The remaining 28 lambs (14 from each diet group) were submitted to 1 of 2 levels of feed restriction: 70% or 50% of the ad libitum intake. Retentions of body fat, N, and energy were determined. Additionally, 6 ram lambs (44.3 ± 5.6 kg BW) were kept in metabolic cages and used in a 6 × 6 Latin square experiment designed to establish the ME content of the 2 diets at the 3 levels of DM intake. There was no effect of intake level on diet ME content, but it was greater in the diet with LQR than in the diet with MQR (3.18 vs. 2.94 Mcal/kg, respectively; P < 0.01). Lambs fed the diet with LQR had greater body fat (g/kg of empty BW) and energy concentrations (kcal/kg of empty BW) because of a larger visceral fat deposition (P < 0.05). Using a low-quality roughage as a primary source of forage in a concentrate-based diet for growing lambs did not change NEm and the efficiency of ME use for maintenance, which averaged 71.6 kcal/kg(0.75) of shrunk BW and 0.63, respectively. On the other hand, the greater nonfibrous carbohydrate content of the diet with

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

    International Nuclear Information System (INIS)

    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.

  8. Using an Explicit Emission Tagging Method in Global Modeling of Source-Receptor Relationships for Black Carbon in the Arctic: Variations, Sources and Transport Pathways

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hailong; Rasch, Philip J.; Easter, Richard C.; Singh, Balwinder; Zhang, Rudong; Ma, Po-Lun; Qian, Yun; Ghan, Steven J.; Beagley, Nathaniel

    2014-11-27

    We introduce an explicit emission tagging technique in the Community Atmosphere Model to quantify source-region-resolved characteristics of black carbon (BC), focusing on the Arctic. Explicit tagging of BC source regions without perturbing the emissions makes it straightforward to establish source-receptor relationships and transport pathways, providing a physically consistent and computationally efficient approach to produce a detailed characterization of the destiny of regional BC emissions and the potential for mitigation actions. Our analysis shows that the contributions of major source regions to the global BC burden are not proportional to the respective emissions due to strong region-dependent removal rates and lifetimes, while the contributions to BC direct radiative forcing show a near-linear dependence on their respective contributions to the burden. Distant sources contribute to BC in remote regions mostly in the mid- and upper troposphere, having much less impact on lower-level concentrations (and deposition) than on burden. Arctic BC concentrations, deposition and source contributions all have strong seasonal variations. Eastern Asia contributes the most to the wintertime Arctic burden. Northern Europe emissions are more important to both surface concentration and deposition in winter than in summer. The largest contribution to Arctic BC in the summer is from Northern Asia. Although local emissions contribute less than 10% to the annual mean BC burden and deposition within the Arctic, the per-emission efficiency is much higher than for major non-Arctic sources. The interannual variability (1996-2005) due to meteorology is small in annual mean BC burden and radiative forcing but is significant in yearly seasonal means over the Arctic. When a slow aging treatment of BC is introduced, the increase of BC lifetime and burden is source-dependent. Global BC forcing-per-burden efficiency also increases primarily due to changes in BC vertical distributions. The

  9. Comparison of different combined treatment processes to address the source water with high concentration of natural organic matter during snowmelt period

    Institute of Scientific and Technical Information of China (English)

    Pengfei Lin; Xiaojian Zhang; Jun Wang; Yani Zeng; Shuming Liu; Chao Chen

    2015-01-01

    The source water in one forest region of the Northeast China had very high natural organic matter (NOM) concentration and heavy color during snowmelt period.The efficiency of five combined treatment processes was compared to address the high concentration of NOM and the mechanisms were also analyzed.Conventional treatment can hardly remove dissolved organic carbon (DOC) in the source water.KMnO4 pre-oxidization could improve the DOC removal to 22.0%.Post activated carbon adsorption improved the DOC removal of conventional treatment to 28.8%.The non-sufficient NOM removal could be attributed to the dominance of large molecular weight organic matters in raw water,which cannot be adsorbed by the micropore upon activated carbon.O3 + activated carbon treatment are another available technology for eliminating the color and UV254 in water.However,its performance of DOC removal was only 36.4%,which could not satisfy the requirement for organic matter.The limited ozone dosage is not sufficient to mineralize the high concentration of NOM.Magnetic ion-exchange resin combined with conventional treatment could remove 96.2% of color,96.0% of UV254 and 87.1% of DOC,enabling effluents to meet the drinking water quality standard.The high removal efficiency could be explained by the negative charge on the surface of NOM which benefits the static adsorption of NOM on the anion exchange resin.The results indicated that magnetic ion-exchange resin combined with conventional treatment is the best available technology to remove high concentration of NOM.

  10. Mathematical modeling of enzyme production using Trichoderma harzianum P49P11 and sugarcane bagasse as carbon source.

    Science.gov (United States)

    Gelain, Lucas; da Cruz Pradella, José Geraldo; da Costa, Aline Carvalho

    2015-12-01

    A mathematical model to describe the kinetics of enzyme production by the filamentous fungus Trichoderma harzianum P49P11 was developed using a low cost substrate as main carbon source (pretreated sugarcane bagasse). The model describes the cell growth, variation of substrate concentration and production of three kinds of enzymes (cellulases, beta-glucosidase and xylanase) in different sugarcane bagasse concentrations (5; 10; 20; 30; 40 gL(-1)). The 10 gL(-1) concentration was used to validate the model and the other to parameter estimation. The model for enzyme production has terms implicitly representing induction and repression. Substrate variation was represented by a simple degradation rate. The models seem to represent well the kinetics with a good fit for the majority of the assays. Validation results indicate that the models are adequate to represent the kinetics for a biotechnological process. PMID:26378961

  11. Variability of levels of PM, black carbon and particle number concentration in selected European cities

    Directory of Open Access Journals (Sweden)

    C. Reche

    2011-03-01

    Full Text Available In many large cities of Europe standard air quality limit values of particulate matter (PM are exceeded. Emissions from road traffic and biomass burning are frequently reported to be the major causes. As a consequence of these exceedances a large number of air quality plans, most of them focusing on traffic emissions reductions, have been implemented in the last decade. In spite of this implementation, a number of cities did not record a decrease of PM levels. Thus, is the efficiency of air quality plans overestimated? Or do we need a more specific metric to evaluate the impact of the above emissions on the levels of urban aerosols?

    This study shows the results of the interpretation of the 2009 variability of levels of PM, black carbon (BC, aerosol number concentration (N and a number of gaseous pollutants in seven selected urban areas covering road traffic, urban background, urban-industrial, and urban-shipping environments from southern, central and northern Europe.

    The results showed that variations of PM and N levels do not always reflect the variation of the impact of road traffic emissions on urban aerosols. However, BC levels vary proportionally with those of traffic related gaseous pollutants, such as CO, NO2 and NO. Due to this high correlation, one may suppose that monitoring the levels of these gaseous pollutants would be enough to extrapolate exposure to traffic-derived BC levels. However, the BC/CO, BC/NO2 and BC/NO ratios vary widely among the cities studied, as a function of distance to traffic emissions, vehicle fleet composition and the influence of other emission sources such as biomass burning. Thus, levels of BC should be measured at air quality monitoring sites.

    During traffic rush hours, a narrow variation in the N/BC ratio was evidenced, but a wide variation of this ratio was determined for the noon period. Although in central and northern Europe N and BC levels tend to vary

  12. Strength of briquettes made of Cu concentrate and carbon-bearing materials

    Directory of Open Access Journals (Sweden)

    B. Oleksiak

    2015-01-01

    Full Text Available In the present paper, results of the research on application of residual fine-grained, carbon-bearing materials as coke substitutes in the shaft process of copper matter smelting are discussed. The addition was introduced into the charge as a component of concentrate-made briquettes, then, its effects on properties of the obtained briquettes were analysed for their compressive and drop strengths. The results of investigations confirmed the potential use of proposed alternative fuels (as briquette components in the process of copper matte smelting.

  13. Carbon Solubility and Mass Action Concentrations of Fe-Cr-C Melts

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An empirical equation of carbon solubility in Fe-Cr-C melts is regressed based on the experimental data from references. A calculating model of mass action concentrations for these melts is formulated on the basis of the coexistence theory of metallic melts involving compound formation, the phase diagram of Cr-C system as well as thermodynamic data of Fe-Cr-C melts. According to the model, the standard Gibbs free energies of formation of CrC and Cr3C2 are obtained. Satisfactory agreement between the calculated and measured values shows that the model can reflect the structural characteristics of Fe-Cr-C melts.

  14. Linking mercury, carbon, and nitrogen stable isotopes in Tibetan biota: Implications for using mercury stable isotopes as source tracers.

    Science.gov (United States)

    Xu, Xiaoyu; Zhang, Qianggong; Wang, Wen-Xiong

    2016-05-06

    Tibetan Plateau is located at a mountain region isolated from direct anthropogenic sources. Mercury concentrations and stable isotopes of carbon, nitrogen, and mercury were analyzed in sediment and biota for Nam Co and Yamdrok Lake. Biotic mercury concentrations and high food web magnification factors suggested that Tibetan Plateau is no longer a pristine site. The primary source of methylmercury was microbial production in local sediment despite the lack of direct methylmercury input. Strong ultraviolet intensity led to extensive photochemical reactions and up to 65% of methylmercury in water was photo-demethylated before entering the food webs. Biota displayed very high Δ(199)Hg signatures, with some highest value (8.6%) ever in living organisms. The δ(202)Hg and Δ(199)Hg in sediment and biotic samples increased with trophic positions (δ(15)N) and %methylmercury. Fish total length closely correlated to δ(13)C and Δ(199)Hg values due to dissimilar carbon sources and methylmercury pools in different living waters. This is the first mercury isotope study on high altitude lake ecosystems that demonstrated specific isotope fractionations of mercury under extreme environmental conditions.

  15. Linking mercury, carbon, and nitrogen stable isotopes in Tibetan biota: Implications for using mercury stable isotopes as source tracers

    Science.gov (United States)

    Xu, Xiaoyu; Zhang, Qianggong; Wang, Wen-Xiong

    2016-05-01

    Tibetan Plateau is located at a mountain region isolated from direct anthropogenic sources. Mercury concentrations and stable isotopes of carbon, nitrogen, and mercury were analyzed in sediment and biota for Nam Co and Yamdrok Lake. Biotic mercury concentrations and high food web magnification factors suggested that Tibetan Plateau is no longer a pristine site. The primary source of methylmercury was microbial production in local sediment despite the lack of direct methylmercury input. Strong ultraviolet intensity led to extensive photochemical reactions and up to 65% of methylmercury in water was photo-demethylated before entering the food webs. Biota displayed very high Δ199Hg signatures, with some highest value (8.6%) ever in living organisms. The δ202Hg and Δ199Hg in sediment and biotic samples increased with trophic positions (δ15N) and %methylmercury. Fish total length closely correlated to δ13C and Δ199Hg values due to dissimilar carbon sources and methylmercury pools in different living waters. This is the first mercury isotope study on high altitude lake ecosystems that demonstrated specific isotope fractionations of mercury under extreme environmental conditions.

  16. Mineral Carbonation Potential of CO2 from Natural and Industrial-based Alkalinity Sources

    Science.gov (United States)

    Wilcox, J.; Kirchofer, A.

    2014-12-01

    Mineral carbonation is a Carbon Capture and Storage (CSS) technology where gaseous CO2 is reacted with alkaline materials (such as silicate minerals and alkaline industrial wastes) and converted into stable and environmentally benign carbonate minerals (Metz et al., 2005). Here, we present a holistic, transparent life cycle assessment model of aqueous mineral carbonation built using a hybrid process model and economic input-output life cycle assessment approach. We compared the energy efficiency and the net CO2 storage potential of various mineral carbonation processes based on different feedstock material and process schemes on a consistent basis by determining the energy and material balance of each implementation (Kirchofer et al., 2011). In particular, we evaluated the net CO2 storage potential of aqueous mineral carbonation for serpentine, olivine, cement kiln dust, fly ash, and steel slag across a range of reaction conditions and process parameters. A preliminary systematic investigation of the tradeoffs inherent in mineral carbonation processes was conducted and guidelines for the optimization of the life-cycle energy efficiency are provided. The life-cycle assessment of aqueous mineral carbonation suggests that a variety of alkalinity sources and process configurations are capable of net CO2 reductions. The maximum carbonation efficiency, defined as mass percent of CO2 mitigated per CO2 input, was 83% for CKD at ambient temperature and pressure conditions. In order of decreasing efficiency, the maximum carbonation efficiencies for the other alkalinity sources investigated were: olivine, 66%; SS, 64%; FA, 36%; and serpentine, 13%. For natural alkalinity sources, availability is estimated based on U.S. production rates of a) lime (18 Mt/yr) or b) sand and gravel (760 Mt/yr) (USGS, 2011). The low estimate assumes the maximum sequestration efficiency of the alkalinity source obtained in the current work and the high estimate assumes a sequestration efficiency

  17. Short-term forecast of the carbon monoxide concentration over the Moscow megacity region by COSMO-ART

    Science.gov (United States)

    Kislov, Alexander; Revokatova, Anastasia; Surkova, Galina; Rivin, Gdaliy

    2016-04-01

    Introduction. Atmospheric pollution in the cities is constantly increasing. It makes air pollution forecast extremely important for modern meteorology. Short-range spatial detailed forecast of air pollutants distribution should be done as a part of weather forecast. A short-term forecast of city 'chemical weather' requires real daily data on pollutant emissions. For the operational daily forecast of pollutant concentrations, long-term emissions averages are usually used, which may differ significantly from real emissions on the particular day, especially in big cities. Methodology. The method of calculation of pollutant emissions is described for the short-term forecast. An on-line coupled chemical transport model, COSMO-ART (https://www.imk-tro.kit.edu/english/3509.php), was applied for the Moscow megasity region, Russia. Because it is impossible to have real daily emissions values, the method of emission estimation on the basis of measurements of the concentrations of air pollutants is proposed. The method is based on the assumption that the pollutant concentrations reflect the intensity of emissions sources. The proposed method allows the hourly measurements of air pollutant concentrations to be transformed into emissions values as fast as the measurements can be done. Results. This method is described and its application is shown for carbon monoxide (one of the most dangerous pollutant). Around 90% of CO in Moscow is emitted by traffic. Conclusions. Verification of the COSMO-ART results demonstrates that the calculated emissions gave better results compared with the results from mean emission values (TNO emissions dataset) that were used previously. This approach provides the possibility of running an operational short-term pollutant concentration forecast with more detailed spatial structure.

  18. Control of phosphorus concentration through adsorption and desorption in shallow groundwater of subtropical carbonate estuary

    Science.gov (United States)

    Flower, Hilary; Rains, Mark; Lewis, David; Zhang, Jia-Zhong; Price, René

    2016-02-01

    The changes in the proportion of fresh and marine water sources in coastal mixing zones can affect phosphorus (P) availability, one of the important drivers of primary productivity. This study focuses on an abiotic portion of the P cycle in the mangrove ecotone of Taylor Slough, coastal Everglades, Florida. We investigated the P sorption properties of sediment with three distinct water sources in this region: 1) fresh groundwater from the inland Everglades, 2) bicarbonate enriched groundwater from the mangrove ecotone, and 3) surface saltwater from Florida Bay. Soluble reactive P (SPR) in ecotone groundwater exhibit markedly low sorption efficiency (Kd = 0.2 L g-1) onto the sediment compared to fresh groundwater and Florida Bay water (11.3 L g-1 and 3.4 L g-1, respectively). The low SRP buffering capacity of the sediment in ecotone groundwater would maintain a higher ambient water SRP concentration in ecotone groundwater than in the other two waters. The relative sorption efficiency is consistent with the measured zero equilibrium SRP concentration being highest in ecotone groundwater (0.094 ± 0.003 μM) and lower in fresh groundwater and Florida Bay surface water (0.075 ± 0.005 μM and 0.058 ± 0.004 μM, respectively). The temporal variability of SRP concentration in groundwater at the ecotone field station is greater than the range of zero equilibrium SRP concentration for all three waters, so very low SRP concentration in the ambient water would induce desorption of P from the sediment. Such desorption processes would result in a higher ambient SRP concentration in ecotone groundwater than the other two water types. Our results suggest that ecotone groundwater, due to its higher bicarbonate content, would release more SRP from mangrove sediments compared to the upstream and downstream waters, as evidenced by both its lower P sorption efficiency and its higher zero equilibrium SRP concentration.

  19. Evaluation of phosphorus source coefficients as predictors of runoff phosphorus concentrations.

    Science.gov (United States)

    Smith, Matt C; White, John W; Coale, Frank J

    2009-01-01

    Many states have adopted a P site index (PSI) as a risk assessment tool to determine when P-based nutrient management is required for a given agricultural field. Some PSIs use a weighting factor, the phosphorus source coefficient (PSC), to account for differences in P solubility between organic P sources. Information relating to appropriate values of PSC for various organic P sources is limited. The objectives of this study were to determine PSCs for organic P sources and to examine the relationship between PSCs and P concentrations measured in simulated rainfall runoff. An incubation study was used to calculate PSCs based on the extractability of P from organic P sources (separated and unseparated liquid dairy manure, digested dairy manure, dairy manure solids, poultry litter, and compost) relative to P from triple superphosphate fertilizer. The PSCs from the 14-d incubations were the best predictors of runoff P after 14 d soil equilibration in the runoff boxes. The values for iron-oxide strip phosphorus (FeO-P) PSC ranged from 78% for compost to 28% for poultry litter and were significantly related to runoff DR-P (r(2) = 0.80***) and FeO-P (r(2) = 0.76***) during the 14-d runoff event. Mehlich 3 PSCs ranged from 59% for compost to 30% for unseparated dairy manure and were better predictors of DR-P and FeO-P during the 56-d event (r(2) = 0.73*** and 0.65***, respectively). The results of this study indicate that PSCs based on soil incubations may improve the ability of PSCs to predict the risk of runoff transport, particularly after manure incorporation. PMID:19202029

  20. Carbon Sequestration through Sustainably Sourced Algal Fertilizer: Deep Ocean Water.

    Science.gov (United States)

    Sherman, M. T.

    2014-12-01

    Drawing down carbon from the atmosphere happens in the oceans when marine plants are growing due to the use of carbon dioxide for biological processes and by raising the pH of the water. Macro- and microscopic marine photosynthesizers are limited in their growth by the availability of light and nutrients (nitrogen, phosphorous, iron, etc.) Deep ocean water (DOW), oceanic water from bellow about 1000m, is a natural medium for marine algae, which contains all (except in rare circumstances) necessary components for algal growth and represents over 90% of the volume of the ocean. The introduction of DOW to a tropical or summer sea can increase chlorophyll from near zero to 60 mg per M3 or more. The form of the utilization infrastructure for DOW can roughly be divided into two effective types; the unconstrained release and the open pond system. Unconstrained release has the advantage of having relatively low infrastructure investment and is available to any area of the ocean. The open pond system has high infrastructure costs but enables intensive use of DOW for harvesting macro- and microalgae and sustainable mariculture. It also enables greater concomitant production of DOW's other potential products such as electricity or potable water. However, unlike an unconstrained release the open pond system can capture much of the biomaterial from the water and limits the impact to the surrounding ecosystem. The Tidal Irrigation and Electrical System (TIESystem), is an open pond that is to be constructed on a continental shelf. It harnesses the tidal flux to pump DOW into the pond on the rising tide and then uses the falling tide to pump biologically rich material out of the pond. This biomaterial represents fixed CO2 and can be used for biofuel or fertilizers. The TIESystem benefits from an economy of scale that increases at a rate that is roughly equal to the relationship of the circumference of a circle (the barrier that creates the open pond) to the area of the pond

  1. Carbon dioxide as working fluid for medium and high-temperature concentrated solar thermal systems

    Directory of Open Access Journals (Sweden)

    Van Duong

    2014-03-01

    Full Text Available This paper explores the benefits and drawbacks of using carbon dioxide in solar thermal systems at medium and high operating temperatures. For medium temperatures, application of CO2 in non-imaging-optics based compound parabolic concentrators (CPC combined with evacuated-tube collectors is studied. These collectors have been shown to obtain efficiencies higher than 40% operating at around 200℃ without the need of tracking. Validated numerical models of external compound parabolic concentrators (XCPCs are used to simulate their performance using CO2 as working fluid. For higher temperatures, a mathematical model is implemented to analyze the operating performance of a parabolic trough solar collector (PTC using CO2 at temperatures between 100℃ and 600℃.

  2. Microbial lipid production by oleaginous yeast Cryptococcus sp. in the batch cultures using corncob hydrolysate as carbon source

    International Nuclear Information System (INIS)

    To realize the feasibility of biodiesel production from high-lipid cell culture, microbial lipid production by the oleaginous yeasts was studied using glucose and sucrose as carbon source. Among the tested strains, Cryptococcus sp. SM5S05 accumulated the highest levels of intracellular lipids. The crude lipid contents of Cryptococcus sp. cultured in yeast malt agar reached 30% on a dry weight basis. The accumulation of lipids strongly depended on carbon/nitrogen ratio and nitrogen concentration. The highest content of lipids, measured at a carbon/nitrogen ratio of 60–90 and at a nitrogen concentration of 0.2%, was 60–57% lipids in the dry biomass. Batch cultures using corncob hydrolysate demonstrated that there was minimal inhibitory effect with a reducing sugar concentration of 60 g l−1 or higher. Batch cultures of Cryptococcus sp. SM5S05 in the corncob hydrolysate medium with 60 g l−1 glucose resulted in a dry biomass, lipid yields, and content of 12.6 g l−1, 7.6 g l−1, and 60.2%, respectively. The lipids contained mainly long-chain saturated and unsaturated fatty acids with 16 and 18 carbon atoms. The fatty acid profile of Cryptococcus oils was quite similar to that of conventional vegetable oil. The cost of lipid production could be further reduced with corncob hydrolysate being utilized as the raw material for the oleaginous yeast. The results showed that the microbial lipid from Cryptococcus sp. was a potential alternative resource for biodiesel production. - Highlights: • Microbial oil production from oleaginous yeast Cryptococcus sp. was studied. • Accumulation of lipid strongly depended on C/N ratio and nitrogen concentration. • Cultures in hydrolysate medium with 60 g/l glucose resulted in maximum lipid yields. • Maximal lipid content in the Cryptococcus sp. were 60.2% on dried weight basis

  3. Concentrations and sources of an emerging pollutant,decabromodiphenylethane(DBDPE), in sewage sludge for land application

    Institute of Scientific and Technical Information of China (English)

    De la Torre A; Concejero M A; Martínez M A

    2012-01-01

    The presence of an emerging brominated flame retardant,decabromodiphenylethane(DBDPE),has been confirmed in Spanish sewage sludge.Thirty one samples from different urban wastewater treatment plants(WWTPs)were analyzed for this brominated flame retardant.DBDPE was positively identified and quantified in all samples at lower concentrations(47.0 ± 29.7 ng/g dry weight(dw);mean ± SD)than those obtained for decabromodiphenyl ether(BDE-209)(290 ± 236 ng/g dw; mean ± SD)in a previous study.Influence of the WWTP characteristics in the pollutant levels was evaluated.No significant correlations were obtained between DBDPE concentrations and the population or sewage sludge production rate associated with the plants,neither wastewater treatment method.Sources of DBDPE in the sludge were also evaluated.Data indicate a common origin for DBDPE and BDE-209,which may be related to leaching processes during the use and disposal of consumer products containing these chemicals.Nevertheless,DBDPE contents are not influenced by industrial activities,which suggests that the infusion of DBDPE commercial mixture is not a source of this chemical into the environment,and indicates that the use of DBDPE in the Spanish industry is still low compared to deca-BDE.

  4. Characteristics and source of black carbon aerosol over Taklimakan Desert

    Institute of Scientific and Technical Information of China (English)

    FU; S.Joshua

    2010-01-01

    Black carbon(BC) and PM10 in the center of the Taklimakan Desert were online monitored in the whole year of 2007.In addi-tion,TSP samples were also synchronously daily collected by medium-volume samplers with Whatman41 filters in the spring of 2007.BC in the dust aerosol was up to 1.14%of the total mass of PM10.A remarkable seasonal variation of BC in the aerosol was observed in the order of winter>spring>autumn>summer.The peak value of BC appeared at midnight while the lowest one in the evening each day,which was just the reverse of that in the urban area.The contribution of BC to the total mass of PM10 on non-dust storm days was~11 times of that in dust storm.Through back trajectory and principal component analysis,it was found that BC in the dust aerosol over Taklimakan Desert might be attributed to the emission from the anthropogenic activities,including domestic heating,cooking,combustion of oil and natural gas,and the medium-range transport from those oases located in the margins of the desert.The total BC aerosol from the Taklimakan Desert to be transported to the eastward downstream was estimated to be 6.3×104 ton yr-1.

  5. Variation in the concentration and age of nonstructural carbon stored in different tree tissues

    Science.gov (United States)

    Richardson, Andrew; Carbone, Mariah; Huggett, Brett; Furze, Morgan; Czimczik, Claudia I.; Xu, Xiaomei

    2014-05-01

    Trees store nonstructural carbon (NSC), in the form of sugars and starch, in the ray parenchyma cells of woody tissues. These reserves provide a carbon buffer when demand (growth, protection, or metabolism) exceeds supply (photosynthesis). This is particularly important in the context of resilience to stress and disturbance, such as might be associated with various global change factors. However, storage allocation processes and the availability of stored reserves remain poorly understood in woody plants. To better understand how NSC reserves are distributed throughout the tree, and the degree to which NSC reserves mix across ring boundaries and tissue types, we destructively sampled two 30-year-old trees (one red oak, Quercus rubra L., and one white pine, Pinus strobus L.) growing at Harvard Forest, an oak-dominated temperate forest in the northeastern United States. We analyzed stemwood samples (divided into individual rings, bark, and phloem), coarse and fine branches, and coarse (separated into three depths) and fine roots for concentrations of total sugars and starch. For a subset of samples we used the radiocarbon (14C) "bomb spike" method to estimate the mean age of extracted sugars and starch. In oak, stemwood sugar and starch concentrations were highest (50 mg/g) in the youngest (most recently-formed) rings, and dropped off rapidly (to 10 mg/g or less) across the 10 most recent rings. In oak phloem tissue, sugar concentrations were high (90 mg/g) compared to starch (10 mg/g). In pine, sugar concentrations dropped off rapidly across the three most recent rings (from 30 mg/g to 10 mg/g) whereas starch concentrations were low even for the youngest rings (10 mg/g or less). In pine, phloem concentrations of both sugar (190 mg/g) and starch (20 mg/g) were both substantially higher than in oak. Such strong radial trends must be accounted for when scaling up to whole-tree budgets, as whole increment cores cannot properly integrate (on a ring-area basis) across the

  6. Sources of uncertainties in modelling black carbon at the global scale

    OpenAIRE

    Vignati, E.; Karl, M; M. Krol; Wilson, J.(School of Physics and Astronomy, University of Birmingham, Birmingham, United Kingdom); Stier, P; F. Cavalli

    2010-01-01

    Our understanding of the global black carbon (BC) cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and those due to the uncertainties in the definition and quantification of the observations, which propagate through to both the emission inventories, and the...

  7. Morphology and Electrochemical Properties of Thermal Modified Nanoporous Carbon as Electrode of Lithium Power Sources

    Directory of Open Access Journals (Sweden)

    V.I. Mandzyuk

    2014-04-01

    Full Text Available The paper explored the effect of thermal modification on morphology of porous carbon material and specific energy parameters of lithium power sources formed on it bases. The structural and sorption properties of these materials – specific surface area, micropore surface, total pore volume, micropore volume, average pore diameter, are defined by low-temperature porometry method. The electro-stimulated diffusion coefficient of lithium ions into porous carbon material is calculated on the bases of galvanostatic intermittent titration.

  8. Carbon sources supporting a diverse fish community in a tropical coastal ecosystem (Gazi Bay, Kenya)

    OpenAIRE

    Nyunja, J.; Ntiba, M.; Onyari, J.; Mavuti, K.; K. Soetaert; BOUILLON, S

    2009-01-01

    Interlinked mangrove-seagrass ecosystems are characteristic features of many tropical coastal areas, where they act as feeding and nursery grounds for a variety of fishes and invertebrates. The autotrophic carbon sources supporting fisheries in Gazi bay (Kenya) were studied in three sites, two located in the tidal creeks flowing through extensive mangrove forests, another site located in the subtidal seagrass meadows, approximately 2.5 km away from the forest. Carbon and nitrogen stable isoto...

  9. Biotechnological Production of Docosahexaenoic Acid Using Aurantiochytrium limacinum: Carbon Sources Comparison And Growth Characterization

    Directory of Open Access Journals (Sweden)

    Sergi Abad

    2015-12-01

    Full Text Available Aurantiochytrium limacinum, a marine heterotrophic protist/microalga has shown interesting yields of docosahexaenoic acid (DHA when cultured with different carbon sources: glucose, pure and crude glycerol. A complete study in a lab-scale fermenter allowed for the characterization and comparison of the growth kinetic parameters corresponding to each carbon source. Artificial Marine Medium (AMM with glucose, pure and crude glycerol offered similar biomass yields. The net growth rates (0.10–0.12 h−1, biomass (0.7–0.8 g cells/g Substrate and product (0.14–0.15 g DHA/g cells yields, as well as DHA productivity were similar using the three carbon sources. Viable potential applications to valorize crude glycerol are envisioned to avoid an environmental problem due to the excess of byproduct.

  10. Sources and delivery of carbon dioxide for enhanced oil recovery. Final report, October 1977--December 1978

    Energy Technology Data Exchange (ETDEWEB)

    Hare, M.; Perlich, H.; Robinson, R.; Shah, M.; Zimmerman, F.

    1978-12-01

    Results are presented from a comprehensive study by Pullman Kellogg, with assistance from Gulf Universities Research Consortium (GURC) and National Cryo-Chemics Incorporated (NCI), of the carbon dioxide supply situation for miscible flooding operations to enhance oil recovery. A survey of carbon dioxide sources within the geographic areas of potential EOR are shown on four regional maps with the tabular data for each region to describe the sources in terms of quantity and quality. Evaluation of all the costs, such as purchase, production, processing, and transportation, associated with delivering the carbon dioxide from its source to its destination are presented. Specific cases to illustrate the use of the maps and cost charts generated in this study have been examined.

  11. Carbon storages in plantation ecosystems in sand source areas of north Beijing, China.

    Directory of Open Access Journals (Sweden)

    Xiuping Liu

    Full Text Available Afforestation is a mitigation option to reduce the increased atmospheric carbon dioxide levels as well as the predicted high possibility of climate change. In this paper, vegetation survey data, statistical database, National Forest Resource Inventory database, and allometric equations were used to estimate carbon density (carbon mass per hectare and carbon storage, and identify the size and spatial distribution of forest carbon sinks in plantation ecosystems in sand source areas of north Beijing, China. From 2001 to the end of 2010, the forest areas increased more than 2.3 million ha, and total carbon storage in forest ecosystems was 173.02 Tg C, of which 82.80 percent was contained in soil in the top 0-100 cm layer. Younger forests have a large potential for enhancing carbon sequestration in terrestrial ecosystems than older ones. Regarding future afforestation efforts, it will be more effective to increase forest area and vegetation carbon density through selection of appropriate tree species and stand structure according to local climate and soil conditions, and application of proper forest management including land-shaping, artificial tending and fencing plantations. It would be also important to protect the organic carbon in surface soils during forest management.

  12. Influence of natural and novel organic carbon sources on denitrification in forest, degraded urban, and restored streams

    Science.gov (United States)

    Organic carbon is important in regulating ecosystem function, and its source and abundance may be altered by urbanization. We investigated shifts in organic carbon quantity and quality associated with urbanization and ecosystem restoration, and its potential effects on denitrific...

  13. Innovative slow-release organic carbon-source material for groundwater in situ denitrification.

    Science.gov (United States)

    Zhang, Dayi; Zhang, Xu; Wang, Yun; Zhou, Guizhong; Li, Guanghe

    2015-01-01

    Slow-release organic carbon-source (SOC) material, a new kind of electron donor for in situ groundwater denitrification, was prepared and evaluated in this study. With starch as a biologically utilized carbon source and polyvinyl alcohol (PVA) as a frame, this material performed controllable carbon release rates and demonstrated stable behaviour during the simulated denitrification process. Raman spectrum analysis showed that the PVA skeleton formed cross-linking network structures for hydrogen-bonded water molecules reset in low temperatures, and the starchy molecules filled in the interspace of the skeleton to form a two-phase interlocking/disperse phase structure. In a static system, carbon release processes followed the Fickian law with (1.294-6.560)×10(-3) mg g(-1) s(-1/2) as the release coefficient. Under domestication and in situ groundwater simulation conditions, SOC material played a favourable role during denitrification, with 1.049±0.165 as an average carbon-nitrogen ratio. The denitrification process followed the law of zero-order kinetics, while the dynamics parameter kN was 0.563-8.753 gN m(-3) d(-1). Generally, SOC material was suggested to be a potential carbon source (electron donor) suitable for in situ groundwater denitrification.

  14. Estimating dissolved organic carbon concentration in turbid coastal waters using optical remote sensing observations

    Science.gov (United States)

    Cherukuru, Nagur; Ford, Phillip W.; Matear, Richard J.; Oubelkheir, Kadija; Clementson, Lesley A.; Suber, Ken; Steven, Andrew D. L.

    2016-10-01

    Dissolved Organic Carbon (DOC) is an important component in the global carbon cycle. It also plays an important role in influencing the coastal ocean biogeochemical (BGC) cycles and light environment. Studies focussing on DOC dynamics in coastal waters are data constrained due to the high costs associated with in situ water sampling campaigns. Satellite optical remote sensing has the potential to provide continuous, cost-effective DOC estimates. In this study we used a bio-optics dataset collected in turbid coastal waters of Moreton Bay (MB), Australia, during 2011 to develop a remote sensing algorithm to estimate DOC. This dataset includes data from flood and non-flood conditions. In MB, DOC concentration varied over a wide range (20-520 μM C) and had a good correlation (R2 = 0.78) with absorption due to coloured dissolved organic matter (CDOM) and remote sensing reflectance. Using this data set we developed an empirical algorithm to derive DOC concentrations from the ratio of Rrs(412)/Rrs(488) and tested it with independent datasets. In this study, we demonstrate the ability to estimate DOC using remotely sensed optical observations in turbid coastal waters.

  15. Measurement of carbon capture efficiency and stored carbon leakage

    Science.gov (United States)

    Keeling, Ralph F.; Dubey, Manvendra K.

    2013-01-29

    Data representative of a measured carbon dioxide (CO.sub.2) concentration and of a measured oxygen (O.sub.2) concentration at a measurement location can be used to determine whether the measured carbon dioxide concentration at the measurement location is elevated relative to a baseline carbon dioxide concentration due to escape of carbon dioxide from a source associated with a carbon capture and storage process. Optionally, the data can be used to quantify a carbon dioxide concentration increase at the first location that is attributable to escape of carbon dioxide from the source and to calculate a rate of escape of carbon dioxide from the source by executing a model of gas-phase transport using at least the first carbon dioxide concentration increase. Related systems, methods, and articles of manufacture are also described.

  16. Determination, source identification and GIS mapping for nitrate concentration in ground water from Bara aquifer

    International Nuclear Information System (INIS)

    The study was carried-out determine the level of nitrate concentration in well water from Bara aquifer in North Kordofan State. The analysis was conducted for 69 wells from different villages within Bara basin. Physical characteristics were measured including pH, electrical conductivity and dissolved oxygen. Spectrophotometric analysis was used to determine nitrate, nitrite and ammonia. Chloride and hardness were determined telemetrically and flame photometer was used for major elements namely sodium and potassium, whereas atomic absorption spectroscopy was used for trace elements namely iron, manganese, zinc and copper. Results revealed that nitrate concentration range from 9.68 to 891 mg/1 in sampled wells with 81% exceeding the maximum permissible limits set for drinking water by WHO and SSMO. Animal waste and organic soil nitrogen were found to be the sources of nitrate in these wells as indicated by 15N%. Majority of wells with high nitrate are located in the north and the north-east part of the study area as shown by GIS predictive map. On the average, the concentrations of sodium, potassium, calcium, magnesium, iron, manganese, zinc and copper were found to be within WHO limits for drinking water. (Author)

  17. Measurements of 222Rn activity concentration in domestic water sources in Penang, northern peninsular Malaysia.

    Science.gov (United States)

    Muhammad, B G; Jaafar, M S; Azhar, A R; Akpa, T C

    2012-04-01

    Measurements of (222)Rn activity concentration were carried out in 39 samples collected from the domestic and drinking water sources used in the island and mainland of Penang, northern peninsular, Malaysia. The measured activity concentrations ranged from 7.49 to 26.25 Bq l(-1), 0.49 to 9.72 Bq l(-1) and 0.58 to 2.54 Bq l(-1) in the raw, treated and bottled water samples collected, respectively. This indicated relatively high radon concentrations compared with that from other parts of the world, which still falls below the WHO recommended treatment level of 100 Bq l(-1). From this data, the age-dependent associated committed effective doses due to the ingestion of (222)Rn as a consequence of direct consumption of drinking water were calculated. The committed effective doses from (222)Rn resulting from 1 y's consumption of these water were estimated to range from 0.003 to 0.048, 0.001 to 0.018 and 0.002 to 0.023 mSv y(-1), for age groups 0-1, 2-16 and >16 y, respectively.

  18. Evaluation of optical source-detector configurations for tomographic reconstruction of chemical concentrations in indoor air.

    Science.gov (United States)

    Todd, L; Ramachandran, G

    1994-12-01

    This article reports on numerical studies to evaluate and compare optical remote sensing configurations for tomographically reconstructing pollutant concentrations in indoor air. With a remote sensing/computed tomography system, two-dimensional maps of pollutant concentrations with good spatial resolution can be created for an entire room. The successful use of such a system for exposure assessment, ventilation assessment, or source monitoring depends on the remote sensing configuration. A systematic method was developed to evaluate the performance of 10 configurations. One hundred and twenty test maps were reconstructed with an algebraic reconstruction method using all 10 configurations; reconstruction quality was evaluated using 4 criteria. Reconstruction quality was related to the number and location of detectors in the room and the complexity of the test maps. Configurations using the same number of detectors placed in different locations resulted in reconstructions that differed in quality. The effect of reducing the number density of rays on reconstruction quality was studied. Based on these simulations, two configurations that used four detectors to scan the room were selected, and their performance was evaluated in the presence of various levels of measurement noise. Two configurations that used four detectors were most suited for exposure assessment. It was found that when designing a configuration, the number and independence of rays should be maximized. Results underscored the need to thoroughly test configurations through numerical studies prior to field implementation; a wide variety of concentration maps, relevant to the application, should be tested under both ideal and nonideal sampling conditions. PMID:7825513

  19. Measurements of 222Rn activity concentration in domestic water sources in Penang, northern peninsular Malaysia.

    Science.gov (United States)

    Muhammad, B G; Jaafar, M S; Azhar, A R; Akpa, T C

    2012-04-01

    Measurements of (222)Rn activity concentration were carried out in 39 samples collected from the domestic and drinking water sources used in the island and mainland of Penang, northern peninsular, Malaysia. The measured activity concentrations ranged from 7.49 to 26.25 Bq l(-1), 0.49 to 9.72 Bq l(-1) and 0.58 to 2.54 Bq l(-1) in the raw, treated and bottled water samples collected, respectively. This indicated relatively high radon concentrations compared with that from other parts of the world, which still falls below the WHO recommended treatment level of 100 Bq l(-1). From this data, the age-dependent associated committed effective doses due to the ingestion of (222)Rn as a consequence of direct consumption of drinking water were calculated. The committed effective doses from (222)Rn resulting from 1 y's consumption of these water were estimated to range from 0.003 to 0.048, 0.001 to 0.018 and 0.002 to 0.023 mSv y(-1), for age groups 0-1, 2-16 and >16 y, respectively. PMID:21642647

  20. Trace elements in particulate matter from metropolitan regions of Northern China: Sources, concentrations and size distributions.

    Science.gov (United States)

    Pan, Yuepeng; Tian, Shili; Li, Xingru; Sun, Ying; Li, Yi; Wentworth, Gregory R; Wang, Yuesi

    2015-12-15

    Public concerns over airborne trace elements (TEs) in metropolitan areas are increasing, but long-term and multi-site observations of size-resolved aerosol TEs in China are still lacking. Here, we identify highly elevated levels of atmospheric TEs in megacities and industrial sites in a Beijing-Tianjin-Hebei urban agglomeration relative to background areas, with the annual mean values of As, Pb, Ni, Cd and Mn exceeding the acceptable limits of the World Health Organization. Despite the spatial variability in concentrations, the size distribution pattern of each trace element was quite similar across the region. Crustal elements of Al and Fe were mainly found in coarse particles (2.1-9 μm), whereas the main fraction of toxic metals, such as Cu, Zn, As, Se, Cd and Pb, was found in submicron particles (soil dust, fossil fuel combustion and industrial emissions, at different sites. In addition, higher elemental concentrations coincided with westerly flow, indicating that polluted soil and fugitive dust were major sources of TEs on the regional scale. However, the contribution of coal burning, iron industry/oil combustion and non-ferrous smelters to atmospheric metal pollution in Northern China should be given more attention. Considering that the concentrations of heavy metals associated with fine particles in the target region were significantly higher than those in other Asian sites, the implementations of strict environmental standards in China are required to reduce the amounts of these hazardous pollutants released into the atmosphere. PMID:26278373

  1. Effect of temperature and concentration on thermal conductivity and viscosity of ferrofluid loaded with carbon nanotubes

    Science.gov (United States)

    Shahsavar, A.; Saghafian, M.; Salimpour, M. R.; Shafii, M. B.

    2016-10-01

    The aim of this paper is to investigate the thermal conductivity and viscosity of a hybrid nanofluid containing tetramethylammonium hydroxide (TMAH) coated Fe3O4 nanoparticles and gum arabic (GA) coated carbon nanotubes (CNTs), experimentally. The magnetic nanoparticles and CNTs are physically attached as the result of interaction between the TMAH and GA molecules. The morphology and structure of the samples are characterized with X-ray diffraction (XRD) and transmission electron microscopy (TEM). The experiments are carried out in the magnetic nanoparticles volume concentration range of 0.1-0.9 %, CNT volume concentration range of 0.05-1.35 % and the temperature range of 25-55 °C. The viscosity of the hybrid nanofluid increases with the increase of volume concentration, while it decreases with the increase of temperature. Besides, results show that hybrid nanofluid behaves as a shear thinning fluid. Furthermore, it is observed that the thermal conductivity of the hybrid nanofluid enhances with temperature and volume concentration.

  2. Effect of temperature and concentration on thermal conductivity and viscosity of ferrofluid loaded with carbon nanotubes

    Science.gov (United States)

    Shahsavar, A.; Saghafian, M.; Salimpour, M. R.; Shafii, M. B.

    2015-12-01

    The aim of this paper is to investigate the thermal conductivity and viscosity of a hybrid nanofluid containing tetramethylammonium hydroxide (TMAH) coated Fe3O4 nanoparticles and gum arabic (GA) coated carbon nanotubes (CNTs), experimentally. The magnetic nanoparticles and CNTs are physically attached as the result of interaction between the TMAH and GA molecules. The morphology and structure of the samples are characterized with X-ray diffraction (XRD) and transmission electron microscopy (TEM). The experiments are carried out in the magnetic nanoparticles volume concentration range of 0.1-0.9 %, CNT volume concentration range of 0.05-1.35 % and the temperature range of 25-55 °C. The viscosity of the hybrid nanofluid increases with the increase of volume concentration, while it decreases with the increase of temperature. Besides, results show that hybrid nanofluid behaves as a shear thinning fluid. Furthermore, it is observed that the thermal conductivity of the hybrid nanofluid enhances with temperature and volume concentration.

  3. Carbon Dioxide Concentrations and Temperatures within Tour Buses under Real-Time Traffic Conditions.

    Directory of Open Access Journals (Sweden)

    Chun-Fu Chiu

    Full Text Available This study monitored the carbon dioxide (CO2 concentrations and temperatures of three 43-seat tour buses with high-passenger capacities in a course of a three-day, two-night school excursion. Results showed that both driver zones and passenger zones of the tour buses achieved maximum CO2 concentrations of more than 3000 ppm, and maximum daily average concentrations of 2510.6 and 2646.9 ppm, respectively. The findings confirmed that the CO2 concentrations detected in the tour buses exceeded the indoor air quality standard of Taiwan Environmental Protection Administration (8 hr-CO2: 1000 ppm and the air quality guideline of Hong Kong Environmental Protection Department (1 hr-CO2: 2500 ppm for Level 1 for buses. Observations also showed that high-capacity tour bus cabins with air conditioning system operating in recirculation mode are severely lacking in air exchange rate, which may negatively impact transportation safety. Moreover, the passenger zones were able to maintain a temperature of between 20 and 25°C during travel, which effectively suppresses the dispersion of volatile organic compounds. Finally, the authors suggest that in the journey, increasing the ventilation frequency of tour bus cabin, which is very beneficial to maintain the travel safety and enhance the quality of travel.

  4. Exposure to moderate concentrations of tropospheric ozone impairs tree stomatal response to carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Onandia, Gabriela [Department of Plant and Environmental Sciences, University of Gothenburg, P. O. Box 461, SE-405 30 Goeteborg (Sweden); Cavanilles Institute of Biodiversity and Evolutionary Biology, Department of Microbiology and Ecology, University of Valencia, E-46100 Burjassot, Valencia (Spain); Olsson, Anna-Karin; Barth, Sabine [Department of Plant and Environmental Sciences, University of Gothenburg, P. O. Box 461, SE-405 30 Goeteborg (Sweden); King, John S. [Department of Forestry and Environmental Resources, Campus Box 8002, North Carolina State University, Raleigh, NC 27695 (United States); Uddling, Johan, E-mail: johan.uddling@dpes.gu.se [Department of Plant and Environmental Sciences, University of Gothenburg, P. O. Box 461, SE-405 30 Goeteborg (Sweden)

    2011-10-15

    With rising concentrations of both atmospheric carbon dioxide (CO{sub 2}) and tropospheric ozone (O{sub 3}), it is important to better understand the interacting effects of these two trace gases on plant physiology affecting land-atmosphere gas exchange. We investigated the effect of growth under elevated CO{sub 2} and O{sub 3}, singly and in combination, on the primary short-term stomatal response to CO{sub 2} concentration in paper birch at the Aspen FACE experiment. Leaves from trees grown in elevated CO{sub 2} and/or O{sub 3} exhibited weaker short-term responses of stomatal conductance to both an increase and a decrease in CO{sub 2} concentration from current ambient level. The impairement of the stomatal CO{sub 2} response by O{sub 3} most likely developed progressively over the growing season as assessed by sap flux measurements. Our results suggest that expectations of plant water-savings and reduced stomatal air pollution uptake under rising atmospheric CO{sub 2} may not hold for northern hardwood forests under concurrently rising tropospheric O{sub 3}. - Exposure to moderate concentrations of tropospheric ozone impairs stomatal CO{sub 2} responsiveness of birch in the Aspen FACE experiment.

  5. Source apportionment of fine PM and sub-micron particle number concentrations at a regional background site in the western Mediterranean: a 2.5 yr study

    Science.gov (United States)

    Cusack, M.; Pérez, N.; Pey, J.; Alastuey, A.; Querol, X.

    2013-02-01

    The chemical composition and sources of ambient fine particulate matter (PM1) over a period of 2.5 yr for a regional background site in the western Mediterranean are presented in this work. Major components (such as SO12-, NO3-, NH4+, organic and elemental carbon) and trace elements were analysed and the emission sources affecting PM1 were determined using Positive Matrix Factorisation (PMF). Furthermore, sub-micron particle number concentrations and the sources of these particles are also presented. Sources of sub-micron particles were determined by Principal Component Analysis (PCA). The mean PM1 concentration for the measurement period was 8.9 μg m-3, with organic matter (OM) and sulphate comprising most of the mass (3.2 and 1.5 μg m-3). A clear seasonal variation was recorded with higher PM1 concentrations in summer (11.2 μg m-3) compared to winter (6.6 μg m-3). This summer increase was due to elevated levels of sulphate and OM. Six sources were identified by PMF: secondary organic aerosol, secondary nitrate, industrial, traffic + biomass burning, fuel oil combustion and secondary sulphate. The daily variations of these sources were also determined, whereby the typically anthropogenic sources displayed elevated concentrations during the week with reductions at weekends. Nitrate levels were elevated in winter and negligible in summer, whereas secondary sulphate levels underwent a contrasting seasonal evolution with highest concentrations in summer, similar to the fuel oil combustion source. The SOA source was influenced by episodes of sustained pollution as a result of anticyclonic conditions occurring during winter, giving rise to thermal inversions and the accumulation of pollutants in the mixing layer. Increased levels in summer were owing to higher biogenic emissions and regional recirculation of air masses. The industrial source decreased in August due to decreased emissions during the vacation period. Increases in the traffic + biomass burning source

  6. Introducing an algal carbon-concentrating mechanism into higher plants: location and incorporation of key components.

    Science.gov (United States)

    Atkinson, Nicky; Feike, Doreen; Mackinder, Luke C M; Meyer, Moritz T; Griffiths, Howard; Jonikas, Martin C; Smith, Alison M; McCormick, Alistair J

    2016-05-01

    Many eukaryotic green algae possess biophysical carbon-concentrating mechanisms (CCMs) that enhance photosynthetic efficiency and thus permit high growth rates at low CO2 concentrations. They are thus an attractive option for improving productivity in higher plants. In this study, the intracellular locations of ten CCM components in the unicellular green alga Chlamydomonas reinhardtii were confirmed. When expressed in tobacco, all of these components except chloroplastic carbonic anhydrases CAH3 and CAH6 had the same intracellular locations as in Chlamydomonas. CAH6 could be directed to the chloroplast by fusion to an Arabidopsis chloroplast transit peptide. Similarly, the putative inorganic carbon (Ci) transporter LCI1 was directed to the chloroplast from its native location on the plasma membrane. CCP1 and CCP2 proteins, putative Ci transporters previously reported to be in the chloroplast envelope, localized to mitochondria in both Chlamydomonas and tobacco, suggesting that the algal CCM model requires expansion to include a role for mitochondria. For the Ci transporters LCIA and HLA3, membrane location and Ci transport capacity were confirmed by heterologous expression and H(14) CO3 (-) uptake assays in Xenopus oocytes. Both were expressed in Arabidopsis resulting in growth comparable with that of wild-type plants. We conclude that CCM components from Chlamydomonas can be expressed both transiently (in tobacco) and stably (in Arabidopsis) and retargeted to appropriate locations in higher plant cells. As expression of individual Ci transporters did not enhance Arabidopsis growth, stacking of further CCM components will probably be required to achieve a significant increase in photosynthetic efficiency in this species. PMID:26538195

  7. North America carbon dioxide sources and sinks: magnitude, attribution, and uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    King, Anthony W.; Hayes, Daniel J.; Huntzinger, Deborah N.; West, Tristram O.; Post, W. M.

    2012-12-01

    North America is both a source and sink of atmospheric CO2. Sources, predominately fossil-fuel combustion in the United States along with contributions from deforestation in Mexico, add CO2 to the atmosphere. Most North America ecosystems, particularly regrowing forests in the United States, are sinks for atmospheric CO2. CO2 is removed from the atmosphere in photosynthesis, converted into biomass and stored as carbon in vegetation, soil and wood products. Fossil-fuel emissions dominate the North American source-sink balance. North America is a net source of atmospheric CO2 with ecosystem sinks balancing approximately 35% of fossil-fuel CO2 emissions from North America.

  8. Physiological responses of Pinus sylvestris to changing carbon dioxide and ozone concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Holopainen, T. [Kuopio Univ. (Finland). Dept. of Ecology and Environmental Science; Palomaeki, V. [Joensuu Univ. (Finland). Faculty of Forestry; Helmisaari, H.S. [Finnish Forest Research Inst., Helsinki (Finland)] [and others

    1996-12-31

    The objective of this research is to study the effects of elevated ozone, carbon dioxide and their combination on ultrastructural, physiological and biochemical responses of Scots pine needles and how these effects are reflected to photosynthesis, carbohydrate and nutrient allocation and finally to shoot and root growth of trees. In addition the interactions of the studied trees and mycorrhizal fungi as well as insect herbivores are studied. The exposures have been running only for two growing periods and it seems necessary to continue the experiment over the third growing season in 1996. Since the analyses are partially incomplete, only preliminary conclusions are possible at the moment. The slightly increased shoot growth and needle width and increased amount of starch in chloroplasts point to the slight stimulating effect of elevated CO{sub 2} among the chamber treatments. Altogether the growth of the seedlings was best in the chamberless treatment indicating a negative chamber effect. The elevated ozone significantly increased the chlorotic mottling and overall yellowing of second year needles as well as caused increased density of chloroplast stroma and declined photosynthesis, all these responses being often related to ozone exposures. The ozone related responses appeared at both CO{sub 2} levels indicating no clear protection due to elevated CO{sub 2}. The ozone or carbon dioxide treatments were not able to significantly change nutrient concentrations, insect herbivory or carbon allocation among the secondary compounds of needles. A tendency of increased carbon allocation to fine roots due to ozone but not so clearly to CO{sub 2} was observed

  9. Glyphosate Utilization as the Source of Carbon: Isolation and Identification of new Bacteria

    Directory of Open Access Journals (Sweden)

    M. Mohsen Nourouzi

    2011-01-01

    Full Text Available Mixed bacteria from oil palm plantation soil (OPS were isolated to investigate their ability to utilize glyphosate as carbon source. Results showed that approximately all of the glyphosate was converted to aminomethyl-phosphonic acid (AMPA (99.5%. It is worthy to note that mixed bacteria were able to degrade only 2% of AMPA to further metabolites. Two bacterial strains i.e. Stenotrophomonas maltophilia and Providencia alcalifaciens were obtained from enrichment culture. Bacterial isolates were cultured individually on glyphosate as a sole carbon source. It was observed that both isolates were able to convert glyphosate to AMPA.

  10. The effect of various carbon sources on the growth of single-celled cyanophyta

    Science.gov (United States)

    Avilov, I. A.; Sidorenkova, E. S.

    1983-01-01

    In 19 strains of unicellular blue-green algae, belonging to general Synechococcus, Synechocystis, Aphanocapsa and Aphanothece, the capacity of growth under mixotrophic conditions in mineral media with organic carbon sources (carbohydrates, polyols) was investigated. At moderate light intensity (1200 lx) and 0.5% of carbon source there was revealed: (1) Stimulation of growth; (2) Partial or complete inhibition of growth; (3) No influence of carbohydrate and polyols on the growth of some algae strains. Three physiological groups for the investigated strains have been outlined on the basis of data obtained. The possibility of using the differences revealed in classification of unicellular blue-green algae is discussed.

  11. Flushing of distal hillslopes as an alternative source of stream dissolved organic carbon in a headwater catchment

    Science.gov (United States)

    Gannon, John P; Bailey, Scott W.; McGuire, Kevin J.; Shanley, James B.

    2015-01-01

    We investigated potential source areas of dissolved organic carbon (DOC) in headwater streams by examining DOC concentrations in lysimeter, shallow well, and stream water samples from a reference catchment at the Hubbard Brook Experimental Forest. These observations were then compared to high-frequency temporal variations in fluorescent dissolved organic matter (FDOM) at the catchment outlet and the predicted spatial extent of shallow groundwater in soils throughout the catchment. While near-stream soils are generally considered a DOC source in forested catchments, DOC concentrations in near-stream groundwater were low (mean = 2.4 mg/L, standard error = 0.6 mg/L), less than hillslope groundwater farther from the channel (mean = 5.7 mg/L, standard error = 0.4 mg/L). Furthermore, water tables in near-stream soils did not rise into the carbon-rich upper B or O horizons even during events. In contrast, soils below bedrock outcrops near channel heads where lateral soil formation processes dominate had much higher DOC concentrations. Soils immediately downslope of bedrock areas had thick eluvial horizons indicative of leaching of organic materials, Fe, and Al and had similarly high DOC concentrations in groundwater (mean = 14.5 mg/L, standard error = 0.8 mg/L). Flow from bedrock outcrops partially covered by organic soil horizons produced the highest groundwater DOC concentrations (mean = 20.0 mg/L, standard error = 4.6 mg/L) measured in the catchment. Correspondingly, stream water in channel heads sourced in part by shallow soils and bedrock outcrops had the highest stream DOC concentrations measured in the catchment. Variation in FDOM concentrations at the catchment outlet followed water table fluctuations in shallow to bedrock soils near channel heads. We show that shallow hillslope soils receiving runoff from organic matter-covered bedrock outcrops may be a major source of DOC in headwater catchments in forested mountainous regions

  12. Flushing of distal hillslopes as an alternative source of stream dissolved organic carbon in a headwater catchment

    Science.gov (United States)

    Gannon, John P.; Bailey, Scott W.; McGuire, Kevin J.; Shanley, James B.

    2015-10-01

    We investigated potential source areas of dissolved organic carbon (DOC) in headwater streams by examining DOC concentrations in lysimeter, shallow well, and stream water samples from a reference catchment at the Hubbard Brook Experimental Forest. These observations were then compared to high-frequency temporal variations in fluorescent dissolved organic matter (FDOM) at the catchment outlet and the predicted spatial extent of shallow groundwater in soils throughout the catchment. While near-stream soils are generally considered a DOC source in forested catchments, DOC concentrations in near-stream groundwater were low (mean = 2.4 mg/L, standard error = 0.6 mg/L), less than hillslope groundwater farther from the channel (mean = 5.7 mg/L, standard error = 0.4 mg/L). Furthermore, water tables in near-stream soils did not rise into the carbon-rich upper B or O horizons even during events. In contrast, soils below bedrock outcrops near channel heads where lateral soil formation processes dominate had much higher DOC concentrations. Soils immediately downslope of bedrock areas had thick eluvial horizons indicative of leaching of organic materials, Fe, and Al and had similarly high DOC concentrations in groundwater (mean = 14.5 mg/L, standard error = 0.8 mg/L). Flow from bedrock outcrops partially covered by organic soil horizons produced the highest groundwater DOC concentrations (mean = 20.0 mg/L, standard error = 4.6 mg/L) measured in the catchment. Correspondingly, stream water in channel heads sourced in part by shallow soils and bedrock outcrops had the highest stream DOC concentrations measured in the catchment. Variation in FDOM concentrations at the catchment outlet followed water table fluctuations in shallow to bedrock soils near channel heads. We show that shallow hillslope soils receiving runoff from organic matter-covered bedrock outcrops may be a major source of DOC in headwater catchments in forested mountainous regions where catchments have exposed or

  13. [Carbon emissions and low-carbon regulation countermeasures of land use change in the city and town concentrated area of central Liaoning Province, China].

    Science.gov (United States)

    Xi, Feng-ming; Liang, Wen-juan; Niu, Ming-fen; Wang, Jiao-yue

    2016-02-01

    Carbon emissions due to land use change have an important impact on global climate change. Adjustment of regional land use patterns has a great scientific significance to adaptation to a changing climate. Based on carbon emission/absorption parameters suitable for Liaoning Province, this paper estimated the carbon emission of land use change in the city and town concentrated area of central Liaoning Province. The results showed that the carbon emission and absorption were separately 308.51 Tg C and 11.64 Tg C from 1997 to 2010. It meant 3.8% of carbon emission. was offset by carbon absorption. Among the 296.87 Tg C net carbon emission of land use change, carbon emission of remaining land use type was 182.24 Tg C, accounting for 61.4% of the net carbon emission, while the carbon emission of land use transformation was 114.63 Tg C, occupying the rest 38.6% of net carbon emission. Through quantifying the mapping relationship between land use change and carbon emission, it was shown that during 1997-2004 the contributions of remaining construction land (40.9%) and cropland transform ation to construction land (40.6%) to carbon emission were larger, but the greater contributions to carbon absorption came from cropland transformation to forest land (38.6%) and remaining forest land (37.5%). During 2004-2010, the land use types for carbon emission and absorption were the same to the period of 1997-2004, but the contribution of remaining construction land to carbon emission increased to 80.6%, and the contribution of remaining forest land to carbon absorption increased to 71.7%. Based on the carbon emission intensity in different land use types, we put forward the low-carbon regulation countermeasures of land use in two aspects. In carbon emission reduction, we should strict control land transformation to construction land, increase the energy efficiency of construction land, and avoid excessive development of forest land and water. In carbon sink increase, we should

  14. [Carbon emissions and low-carbon regulation countermeasures of land use change in the city and town concentrated area of central Liaoning Province, China].

    Science.gov (United States)

    Xi, Feng-ming; Liang, Wen-juan; Niu, Ming-fen; Wang, Jiao-yue

    2016-02-01

    Carbon emissions due to land use change have an important impact on global climate change. Adjustment of regional land use patterns has a great scientific significance to adaptation to a changing climate. Based on carbon emission/absorption parameters suitable for Liaoning Province, this paper estimated the carbon emission of land use change in the city and town concentrated area of central Liaoning Province. The results showed that the carbon emission and absorption were separately 308.51 Tg C and 11.64 Tg C from 1997 to 2010. It meant 3.8% of carbon emission. was offset by carbon absorption. Among the 296.87 Tg C net carbon emission of land use change, carbon emission of remaining land use type was 182.24 Tg C, accounting for 61.4% of the net carbon emission, while the carbon emission of land use transformation was 114.63 Tg C, occupying the rest 38.6% of net carbon emission. Through quantifying the mapping relationship between land use change and carbon emission, it was shown that during 1997-2004 the contributions of remaining construction land (40.9%) and cropland transform ation to construction land (40.6%) to carbon emission were larger, but the greater contributions to carbon absorption came from cropland transformation to forest land (38.6%) and remaining forest land (37.5%). During 2004-2010, the land use types for carbon emission and absorption were the same to the period of 1997-2004, but the contribution of remaining construction land to carbon emission increased to 80.6%, and the contribution of remaining forest land to carbon absorption increased to 71.7%. Based on the carbon emission intensity in different land use types, we put forward the low-carbon regulation countermeasures of land use in two aspects. In carbon emission reduction, we should strict control land transformation to construction land, increase the energy efficiency of construction land, and avoid excessive development of forest land and water. In carbon sink increase, we should

  15. Carbon isotopes and iodine concentrations in a Mississippi River delta core recording land use, sediment transport, and dam building in the river's drainage basin.

    Science.gov (United States)

    Santschi, Peter H; Oktay, Sarah D; Cifuentes, Luis

    2007-04-01

    Sedimentary material from coastal and nearshore areas in the Mississippi Delta region are comprised of different organic carbon sources with diverse ages that require isotopic and elemental records for resolving the various sources of plant residues. Carbon isotopic ((13)C, (14)C) values were used to differentiate contributions from plants using the C3, C4, and/or CAM (crassulacean acid metabolism) carbon fixation pathways., and iodine concentrations indicated that wetland plant residues are a significant source of organic carbon in a sediment core from the Mississippi River delta region collected at a 60 m water depth. This sediment core had been extensively described in Oktay et al. [Oktay, S.D., Santschi, P.H., Moran, J.E., Sharma, P., 2000. The (129)Iodine Bomb Pulse Recorded in Mississippi River delta Sediments: Results from Isotopes of I, Pu, Cs, Pb, and C. Geochim. Cosmochim. Acta 64 (6), 989-996.] and significantly, includes unique features that had not previously been seen in the marine environment. These special features include a plutonium isotopic close-in fallout record that indicates a purely terrestrial source for these sediment particles and the elements associated with it, and a distinct iodine isotopic peak (as well as peaks for plutonium and cesium isotopes) that indicate little bioturbation in this core. Our carbon isotopic and iodine data can thus be compared to published records of changes in drainage basin land use, river hydrology, and hydrodynamic sorting of suspended particles to elucidate if these changes are reflected in nearshore sediments. This comparison suggests a significant contribution for organic carbon (OC) from C4 plants to these sediments during the 1950's to early 1960's. Relative older carbon isotopes, and episodically high iodine concentrations (up to 34 ppm) were observed during this time period that (1) indicate sediment deposition that is coincident with the times of major hydrological changes induced from dam and levee

  16. The concentration and isotopic composition of carbon in basaltic glasses from the Juan de Fuca Ridge, Pacific Ocean

    Science.gov (United States)

    Blank, Jennifer G.; Delaney, John R.; Des Marais, David J.

    1993-01-01

    The abundance and C-13/C-12 ratios of carbon were analyzed in basaltic glass from twenty locations along the Juan de Fuca Ridge using a 3-step combustion/extraction technique. Carbon released during the first two combustion steps at 400-500 C and 600-650 C is interpreted to be secondary, and only the carbon recovered during a final combustion step at about 1200 C is thought to be indigenous to the samples. For carbon released at about 1200 C, glasses analyzed as 1-2 mm chips contained 23-146 ppm C with delta C-13 values of -4.8 to -9.3 per mil, whereas samples crushed to 38-63 microns or 63-90 microns yielded 56-103 ppm C with delta C-13 values of -6.1 to -9.2 per mil. The concentrations and isotopic compositions of the primary carbon dissolved in the glasses and present in the vesicles are similar to those previously reported for other ocean-ridge basalts. The Juan de Fuca basaltic magmas were not in equilibrium with respect to carbon when they erupted and quenched on the sea floor. Evidence of disequilibrium includes (1) a large range of carbon contents among glasses collected at similar depths, (2) a highly variable calculated carbon isotopic fractionation between melt and vapor determined by comparing crushed and uncrushed splits of the same sample, and (3) a lack of correlation between vesicle abundance, carbon concentration, and depth of eruption. Variations in carbon concentration and delta C-13 ratios along the ridge do not correlate with major element chemistry. The observed relationship between carbon concentrations and delta C-13 values may be explained by late-stage, variable degrees of open-system (Rayleigh-like) degassing.

  17. Sources and transportation of suspended matter and sediment in the southern Yellow Sea: Evidence from stable carbon isotopes

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The concentrations of total suspended matter (TSM) and the compositions of organic stable carbon isotopes of TSM and bottom sediments were analyzed to study the sources of TSM and sediments and the transportation processes. For this study, 284 TSM samples and 64 sediment ones taken from 67 stations along 7 transects and in 5 layers were collected in the southern Yellow Sea on the cruise in May, 1998. The main sediment transportation pattern in the southern Yellow Sea was obtained by analyzing the distribution characteristics of TSM concentration and particulate organic carbon Δ13c values. It was confirmed from the pattern that the bottom layer plays a more important role than the surface one in the transportation processes of terrigenous material to the central deep-water area of the southern Yellow Sea. The Yellow Sea circulation is an important control factor in determining the sediment transportation pattern in the southern Yellow Sea. The carbon isotope signals of sedimentary organic matter confirmed that the main material in sediments with high sedimentation rate in the Shandong subaqueous delta originated from the modern Yellow River. The terrigenous sediments in the deep-water area of the southern Yellow Sea are mainly from the abandoned Yellow River and the modern Yellow River, and a small portion of them are from the modern Yangtze material. The amount of terrigenous material from Korean Peninsula and its influen- ce range are relatively limited. The conclusions derived from TSM and stable carbon isotopes were further confirmed by another independent material source tracer--PAHs.

  18. Evaluation of gasoline-denatured ethanol as a carbon source for denitrification.

    Science.gov (United States)

    Kazasi, Anna; Boardman, Gregory D; Bott, Charles B

    2013-06-01

    In this study concerning denitrification, the performance of three carbon sources, methanol (MeOH), ethanol (EtOH) and gasoline-denatured ethanol (dEtOH), was compared and evaluated on the basis of treatment efficiency, inhibition potential and cost. The gasoline denaturant considered here contained mostly aliphatic compounds and little of the components that typically boost the octane rating, such as benzene, toluene, ethylbenzene and xylenes. Results were obtained using three lab-scale SBRs operated at SRT of 12.0 +/- 0.9 days. After biomass was acclimated, denitrification rates with dEtOH were similar to those of EtOH (201 +/- 50 and 197 +/- 28 NO3-N/g MLVSS x d, respectively), and higher than those of MeOH (165 +/- 49 mg NO3-N/g MLVSS x d). The denaturant did not affect biomass production, nitrification or denitrification. Effluent soluble COD concentrations were always less than the analytical detection limit. Although the cost of dEtOH ($2.00/kg nitrate removed) was somewhat higher than that of methanol ($1.63/kg nitrate removed), the use of dEtOH is very promising and utilities will have to decide if it is worth paying a little extra to take advantage of its benefits.

  19. CO2 mitigation potential of mineral carbonation with industrial alkalinity sources in the United States.

    Science.gov (United States)

    Kirchofer, Abby; Becker, Austin; Brandt, Adam; Wilcox, Jennifer

    2013-07-01

    The availability of industrial alkalinity sources is investigated to determine their potential for the simultaneous capture and sequestration of CO2 from point-source emissions in the United States. Industrial alkalinity sources investigated include fly ash, cement kiln dust, and iron and steel slag. Their feasibility for mineral carbonation is determined by their relative abundance for CO2 reactivity and their proximity to point-source CO2 emissions. In addition, the available aggregate markets are investigated as possible sinks for mineral carbonation products. We show that in the U.S., industrial alkaline byproducts have the potential to mitigate approximately 7.6 Mt CO2/yr, of which 7.0 Mt CO2/yr are CO2 captured through mineral carbonation and 0.6 Mt CO2/yr are CO2 emissions avoided through reuse as synthetic aggregate (replacing sand and gravel). The emission reductions represent a small share (i.e., 0.1%) of total U.S. CO2 emissions; however, industrial byproducts may represent comparatively low-cost methods for the advancement of mineral carbonation technologies, which may be extended to more abundant yet expensive natural alkalinity sources. PMID:23738892

  20. Effect of emissions uncertainty and variability on high-resolution concentrations of carbon monoxide, fine particle black carbon, and nitrogen oxides in Fort Collins, Colorado: development of a Bayesian uncertainty modeling and evaluation framework

    Science.gov (United States)

    Mendoza, D. L.; Stuart, A. L.; Dagne, G.; Yu, H.

    2013-12-01

    Uncertainties in emissions estimates are known to be one of the primary sources of uncertainty in calculating concentrations and subsequent exposure estimates. Despite continued improvement in the accuracy of emissions downscaling, the quantification of uncertainties is necessary in order to generate a representative emissions product. Bayesian data assimilation is a promising approach to uncertainty estimation when used to calibrate model results with measurement data. This study discusses an emissions inventory and concentration estimates for carbon monoxide (CO), fine particle (PM2.5) black carbon, and nitrogen oxides (NOx) for the city of Fort Collins, Colorado. The development of a Bayesian framework for updating estimates of emissions and concentrations in multiple stages, using measurement data, is also presented. The emissions inventory was constructed using the 2008 National Emissions Inventory (NEI). The spatial and temporal allocation methods from the Emission Modeling Clearinghouse data set are used to downscale the NEI data from annual and county-level resolution for point, nonpoint, and nonroad sources. Onroad mobile source emissions were estimated by combining a bottom-up emissions calculation approach (using emission factors and activities) for large roadway links within Fort Collins with a top-down spatial allocation approach for other roadways. Vehicle activity data for road links were obtained from local 2009 travel demand model results and automatic traffic recorder (ATR) data. The CALPUFF Gaussian puff dispersion model was used to estimate air pollutant concentrations. Hourly, 1.33 km x 1.33 km MM5 meteorological data was used to capture temporal variability in transport. Distributions of concentrations are obtained for spatial locations and time spans using a Monte Carlo sampling approach. Data for ensemble members are sampled from distributions defined from the emissions inventory and meteorological data. Modeled concentrations of CO, PM2

  1. Modelling geosmin concentrations in three sources of raw water in Quebec, Canada.

    Science.gov (United States)

    Parinet, Julien; Rodriguez, Manuel J; Sérodes, Jean-Baptiste

    2013-01-01

    The presence of off-flavour compounds such as geosmin, often found in raw water, significantly reduces the organoleptic quality of distributed water and diverts the consumer from its use. To adapt water treatment processes to eliminate these compounds, it is necessary to be able to identify them quickly. Routine analysis could be considered a solution, but it is expensive and delays associated with obtaining the results of analysis are often important, thereby constituting a serious disadvantage. The development of decision-making tools such as predictive models seems to be an economic and feasible solution to counterbalance the limitations of analytical methods. Among these tools, multi-linear regression and principal component regression are easy to implement. However, due to certain disadvantages inherent in these methods (multicollinearity or non-linearity of the processes), the use of emergent models involving artificial neurons networks such as multi-layer perceptron could prove to be an interesting alternative. In a previous paper (Parinet et al., Water Res 44: 5847-5856, 2010), the possible parameters that affect the variability of taste and odour compounds were investigated using principal component analysis. In the present study, we expand the research by comparing the performance of three tools using different modelling scenarios (multi-linear regression, principal component regression and multi-layer perceptron) to model geosmin in drinking water sources using 38 microbiological and physicochemical parameters. Three very different sources of water, in terms of quality, were selected for the study. These sources supply drinking water to the Québec City area (Canada) and its vicinity, and were monitored three times per month over a 1-year period. Seven different modelling methods were tested for predicting geosmin in these sources. The comparison of the seven different models showed that simple models based on multi-linear regression provide sufficient

  2. Effect of different carbon sources on the biological phosphorus removal by a sequencing batch reactor using pressurized pure oxygen

    OpenAIRE

    Wei, Jie; Imai, Tsuyoshi; Higuchi, Takaya; Arfarita, Novi; YAMAMOTO, Koichi; Sekine, Masahiko; Kanno, Ariyo

    2014-01-01

    The effect of different carbon source on the efficiency of enhanced biological phosphorus removal (EBPR) from synthetic wastewater with acetate and two ratios of acetate/starch as a carbon source was investigated. Three pressurized pure oxygen sequencing batch reactor (POSBR) experiments were operated. The reactors (POSBR1, POSBR2 and POSBR3) were developed and studied at different carbon source ratios of 100% acetate, 75% acetate plus 25% starch and 50% acetate plus 50% starch, respectively....

  3. An assessment on in-vehicle concentration of carbon monoxide for taxis in central business district of Tehran

    Directory of Open Access Journals (Sweden)

    Nabi ollah Mansouri

    2013-01-01

    Full Text Available Background and Aim: Carbon monoxide is colorless and odorless gas. In high concentrations, CO is deadly poisonous and in low concentrations can cause fatigue, headache, dizziness and seizures. Carbon monoxide has a high affinity to combines hemoglobin which can decrease oxygen capacity in blood. To address this problem, human body begins to produce red blood cells, this can increases blood viscosity and thus increase diseases such as stroke and heart attack. About 60 percent of total emissions of carbon monoxide are associated automobile exhaust. In this study, concentration of carbon monoxide has been measured in the cabin space of taxis in high-traffic areas of Tehran.Materials and Methods: This study is carried out in spring and summer 2011. Concentrations of carbon monoxide in different types of taxi cabin space (Peugeot, Samand, Pride and Peykan were measured by carbon monoxide meter Q RAE 2 models in different conditions of motion: high speed (over 45 kilometers per hour, low speed (15-30 kilometers per hour and stop (0 kilometers per hour. Results: Results showed that concentration of carbon monoxide in old vehicles (above 10 years is more than three times compared to new vehicles and outdoor. In addition, according to the measured values, at low speeds, values of CO rapidly increased, so that in speeds of less than 15 km, values of CO go beyond standard values (9 ppm.Conclusion: Results show that the mean value of the measured concentration of carbon monoxide is higher than amounts recommended by WHO and EPA and local authorities such as Air Quality Control Organization of Tehran. Concentrations observed in this study are up to 40 more than results of a study by German researchers in summer 1995 and winter 1996.

  4. Temperature-dependent accumulation mode particle and cloud nuclei concentrations from biogenic sources during WACS 2010

    Directory of Open Access Journals (Sweden)

    L. Ahlm

    2012-10-01

    Full Text Available Submicron aerosol particles collected simultaneously at the mountain peak (2182 m a.s.l. and at a forested mid-mountain site (1300 m a.s.l. on Whistler Mountain, British Columbia, Canada, during June and July 2010 were analyzed by Fourier transform infrared (FTIR spectroscopy for quantification of organic functional groups. Positive matrix factorization (PMF was applied to the FTIR spectra. Three PMF factors associated with (1 combustion, (2 biogenics, and (3 vegetative detritus, were identified at both sites. The biogenic factor was correlated with both temperature and several volatile organic compounds (VOCs. The combustion factor dominated the submicron particle mass during the beginning of the campaign when the temperature was lower and advection was from the Vancouver area, but as the temperature started to rise in early July the biogenic factor came to dominate as a result of increased emissions of biogenic VOCs and thereby increased formation of secondary organic aerosol (SOA. On average, the biogenic factor represented 69% and 49% of the submicron organic particle mass at Whistler Peak and at the mid-mountain site, respectively. The lower fraction at the mid-mountain site was a result of more vegetative detritus there, and also higher influence from local combustion sources.

    The biogenic factor was strongly correlated (r ~ 0.9 to number concentration of particles with diameter (Dp> 100 nm, whereas the combustion factor was better correlated to number concentration of particles with Dp < 100 nm (r~ 0.4. The number concentration of cloud condensation nuclei (CCN was correlated (r ~ 0.7 to the biogenic factor for supersaturations (S of 0.2% or higher, which indicates that particle condensational growth from biogenic vapors was an important factor in controlling the CCN concentration for clouds where S≥0.2%. Both the number concentration of particles with

  5. Temperature-dependent accumulation mode particle and cloud nuclei concentrations from biogenic sources during WACS 2010

    Directory of Open Access Journals (Sweden)

    L. Ahlm

    2013-03-01

    Full Text Available Submicron aerosol particles collected simultaneously at the mountain peak (2182 m a.s.l. and at a forested mid-mountain site (1300 m a.s.l. on Whistler Mountain, British Columbia, Canada, during June and July 2010 were analyzed by Fourier transform infrared (FTIR spectroscopy for quantification of organic functional groups. Positive matrix factorization (PMF was applied to the FTIR spectra. Three PMF factors associated with (1 combustion, (2 biogenics, and (3 vegetative detritus were identified at both sites. The biogenic factor was correlated with both temperature and several volatile organic compounds (VOCs. The combustion factor dominated the submicron particle mass during the beginning of the campaign, when the temperature was lower and advection was from the Vancouver area, but as the temperature started to rise in early July, the biogenic factor came to dominate as a result of increased emissions of biogenic VOCs, and thereby increased formation of secondary organic aerosol (SOA. On average, the biogenic factor represented 69% and 49% of the submicron organic particle mass at Whistler Peak and at the mid-mountain site, respectively. The lower fraction at the mid-mountain site was a result of more vegetative detritus there, and also higher influence from local combustion sources. The biogenic factor was strongly correlated (r~0.9 to number concentration of particles with diameter (Dp> 100 nm, whereas the combustion factor was better correlated to number concentration of particles with Dpr~0.4. The number concentration of cloud condensation nuclei (CCN was correlated (r~0.7 to the biogenic factor for supersaturations (S of 0.2% or higher, which indicates that particle condensational growth from biogenic vapors was an important factor in controlling the CCN concentration for clouds where S≥0.2%. Both the number concentration of particles with Dp>100 nm and numbers of CCN for S≥0.2% were correlated to temperature. Considering the biogenic

  6. 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

  7. 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

  8. Immune response and disease resistance of shrimp fed biofloc grown on different carbon sources.

    Science.gov (United States)

    Ekasari, Julie; Hanif Azhar, Muhammad; Surawidjaja, Enang H; Nuryati, Sri; De Schryver, Peter; Bossier, Peter

    2014-12-01

    The objective of this study was to document the immunological effects of growing shrimp in biofloc systems. The experiment consisted of four types of biofloc systems in which bioflocs were produced by daily supplementation of four different carbon sources, i.e. molasses, tapioca, tapioca-by-product, and rice bran, at an estimated C/N ratio of 15 and a control system without any organic carbon addition. Each biofloc system was stocked with Pacific white shrimp (Litopenaeus vannamei) juveniles that were reared for 49 days. The use of tapioca-by-product resulted in a higher survival (93%) of the shrimp as compared to the other carbon sources and the control. The highest yield and protein assimilation was observed when tapioca was used as the carbon source. After 49 days, phenoloxidase (PO) activity of the shrimp grown in all biofloc systems was higher than that of the shrimp from the control system. Following a challenge test by injection with infectious myonecrosis virus (IMNV), the levels of PO and respiratory burst (RB) activity in the shrimp of all biofloc treatments were higher than that of the challenged shrimp from the control treatment. An increased immunity was also suggested by the survival of the challenged shrimp from the experimental biofloc groups that was significantly higher as compared to the challenged shrimp from the control treatment, regardless of the organic carbon source used to grow the bioflocs. Overall, this study demonstrated that the application of biofloc technology may contribute to the robustness of cultured shrimp by immunostimulation and that this effect is independent of the type of carbon source used to grow the flocs. PMID:25218685

  9. Source apportionment of atmospheric particulate carbon in Las Vegas, Nevada,USA

    Institute of Scientific and Technical Information of China (English)

    Mark C.Green; Judith C.Chow; M.-C.Oliver Chang; L.-W.Antony Chen; Hampden D.Kuhns; Vicken R.Etyemezian; John G.Watson

    2013-01-01

    A study was conducted to quantify wintertime contributions of source types to carbonaceous PM2.5 at four urban sites in the Las Vegas Valley,one of the most rapidly growing urban areas in the southwestern United States.Twenty-four hour average ambient samples were collected for mass,ions,elements,organic carbon (OC),elemental carbon (EC),and trace organic markers analysis.Additional measurements were made to determine diurnal patterns in light-absorbing black carbon (BC) as a marker for combustion sources.Carbonaceous PM sources of on-road gasoline vehicles,on-road diesel vehicles,and off-road diesel engines were characterized with their chemical profiles,as well as fuel-based emission factors,using an In-Plume Sampling System.The Effective Variance Chemical Mass Balance (EV-CMB) source apportionment model was applied to the ambient samples collected,using source profiles developed in this study as well as profiles from other relevant studies.Four main sources contributed to PM2.5 carbon within the Las Vegas Valley:(1) paved road dust,(2) on-road gasoline vehicles,(3) residential wood combustion,and (4) on-road diesel vehicles.CMB estimated that on-road mixed fleet gasoline vehicles are the largest source for OC and EC at all the sites.The contribution of paved road dust to both OC and EC was 5-10% at the four sites.On-road diesel vehicles contribute 22% of the OC and 34% of the EC at a site near the city center,which is located immediately downwind of a major freeway.Residential wood combustion is a more important source than on-road diesel vehicles for two residential neighborhood sites.These results are consistent with our conceptual model,and the research methodology may be applied to studying other urban areas.

  10. Comparison of black carbon (BC) aerosols in two urban areas - concentrations and size distributions

    Science.gov (United States)

    Hitzenberger, R.; Tohno, S.

    In this study, the BC aerosol measured at two very different urban sites is compared in terms of concentration, seasonal variation, and size distribution. During a 14 month study, one impactor sample was performed each month on a day with typical meteorological conditions. One (Vienna) or three (Uji) filter samples were obtained during the sampling time of the impactors. BC concentration in both the filter and impactor samples was analyzed with an optical technique (integrating sphere technique), where a calibration curve obtained from commercial carbon black is used to convert the optical signal to BC mass. Gravimetric mass concentration was measured at both sites. The gravimetric mass size distribution was measured only in Vienna. At both sites, the yearly average of the BC concentration on the sampling days was around 5 μg m -3. In Vienna, some seasonal trend with high concentrations during the cold season was observed, while in Uji, no pronounced seasonal trend was found. The BC size distribution in Uji was distinctly bimodal in the submicron size range. Log-normal distributions were fitted through the impactor data. The average BC mass median diameters (MMD) of the two submicron modes were 0.15 and 0.39 μm. Each mode contained about the same amount of BC mass. In Vienna only one submicron BC mode (average MMD 0.3 μm) was found because of the low size resolution of the impactor. An analysis of humidity effects on the MMDs of BC (both sites) and gravimetric mass (Vienna only) indicates that the Vienna aerosol is partly mixed internally with respect to BC, while the Uji aerosol seems to be externally mixed.

  11. Arsenic Adsorption Equilibrium Concentration and Adsorption Rate of Activated Carbon Coated with Ferric-Aluminum Hydroxides

    Science.gov (United States)

    Zhang, M.; Sugita, H.; Oguma, T.; Hara, J.; Takahashi, S.

    2015-12-01

    In some areas of developing countries, ground or well water contaminated with arsenic has been reluctantly used as drinking water. It is highly desirable that effective and inexpensive arsenic removal agents should be developed and provided to reduce the potential health risk. Previous studies demonstrated that activated carbon coated with ferric-aluminum hydroxides (Fe-Al-C) has high adsorptive potential for removal of arsenic. In this study, a series of experiments using Fe-Al-C were carried to discuss adsorption equilibrium time, adsorption equilibrium concentration and adsorption rate of arsenic for Fe-Al-C. Fe-Al-C used in this study was provided by Astec Co., Ltd. Powder reagent of disodium hydrogen arsenate heptahydrate was dissolved into ion-exchanged water. The solution was then further diluted with ion-exchanged water to be 1 and 10 mg/L as arsenic concentration. The pH of the solution was adjusted to be around 7 by adding HCl and/or NaOH. The solution was used as artificial arsenic contaminated water in two types of experiments (arsenic adsorption equilibrium and arsenic adsorption rate tests). The results of the arsenic equilibrium tests were showed that a time period of about 3 days to reach apparent adsorption equilibrium for arsenic. The apparent adsorption equilibrium concentration and adsorbed amount of arsenic on Fe-Al-C adsorbent could be estimated by application of various adsorption isotherms, but the distribution coefficient of arsenic between solid and liquid varies with experimental conditions such as initial concentration of arsenic and addition concentration of adsorbent. An adsorption rate equation that takes into account the reduction in the number of effective adsorption sites on the adsorbent caused by the arsenic adsorption reaction was derived based on the data obtained from the arsenic adsorption rate tests.

  12. Observation of vertical variability of black carbon concentration in lower troposphere on campaigns in Poland

    Science.gov (United States)

    Chilinski, M. T.; Markowicz, K. M.; Markowicz, J.

    2016-07-01

    This study presents two methods for observation of black carbon (BC) vertical profiles in lower troposphere based on the micro-aethalometer AE-51. In the first method micro-aethalometer was carried by observer along trail on slope of mountain valley. Second method uses unmanned aerial vehicle as a platform for collecting data up to 1500 m above ground. Our study presents vertical profiles collected in and above Subcarphatian Wislok valley. Profiles measured on trial on slopes of Wislok valley, were collected during strong smog conditions during autumn/winter season, when BC concentration reached values above 60 μg/m3. The smog intensive layer is usually close to the surface (up to 100 m) as a results of surface inversion and the mountain breeze circulation, which during the night transports air pollution emitted from houses toward the valley's bottom. Usually the vertical profiles of BC concentration show significant reduction with the altitude, however, some multilayered structures are also observed during night time inversion conditions. It has found that smog condition can develop in clean air mass, and in those cases local pollution has significant impact on the columnar aerosol properties. During such conditions the aerosol optical depth shows diurnal cycle which is rather not observed in the long-term data. UAV flights in the lower troposphere were conducted during two sessions, one with clean polar air masses (BC concentration < 1 μg/m3) and second with moderate aerosol conditions (BC concentration 1-5 μg/m3). Profile of BC concentration shows stratification of absorbing aerosols in a shape of multi-layer structures similarly to the lidar/ceilometer signals.

  13. Quantifying sources, transport, deposition, and radiative forcing of black carbon over the Himalayas and Tibetan Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Rudong; Wang, Hailong; Qian, Yun; Rasch, Philip J.; Easter, Richard C.; Ma, Po-Lun; Singh, Balwinder; Huang, Jianping; Fu, Qiang

    2015-01-01

    Black carbon (BC)particles over the Himalayas and Tibetan Plateau (HTP), both airborne and those deposited on snow, have been shown to affect snowmelt and glacier retreat. Since BC over the HTP may originate from a variety of geographical regions and emission sectors, it is essential to quantify the source-receptor relationships of BC in order to understand the contributions of natural and anthropogenic emissions and provide guidance for potential mitigation actions. In this study, we use the Community Atmosphere Model version 5 (CAM5) with a newly developed source tagging technique, nudged towards the MERRA meteorological reanalysis, to characterize the fate of BC particles emitted from various geographical regions and sectors. Evaluated against observations over the HTP and surrounding regions, the model simulation shows a good agreement in the seasonal variation of the near-surface airborne BC concentrations, providing confidence to use this modeling framework for characterizing BC source- receptor relationships. Our analysis shows that the relative contributions from different geographical regions and source sectors depend on seasons and the locations in the HTP. The largest contribution to annual mean BC burden and surface deposition in the entire HTP region is from biofuel and biomass (BB) emissions in South Asia, followed by fossil fuel (FF) emissions from South Asia, then FF from East Asia. The same roles hold for all the seasonal means except for the summer when East Asia FF becomes more important. For finer receptor regions of interest, South Asia BB and FF have the largest impact on BC in Himalayas and Central Tibetan Plateau, while East Asia FF and BB contribute the most to Northeast Plateau in all seasons and Southeast Plateau in the summer. Central Asia and Middle East FF emissions have relatively more important contributions to BC reaching Northwest Plateau, especially in the summer. Although the HTP local emissions only contribute about 10% of BC in

  14. Tracking Nonpoint Source Nitrogen and Carbon in Watersheds of Chesapeake Bay

    Science.gov (United States)

    Kaushal, S.; Pennino, M. J.; Duan, S.; Blomquist, J.

    2012-12-01

    Humans have altered nitrogen and carbon cycles in rivers regionally with important impacts on coastal ecosystems. Nonpoint source nitrogen pollution is a leading contributor to coastal eutrophication and hypoxia. Shifts in sources of carbon impact downstream ecosystem metabolism and fate and transport of contaminants in coastal zones. We used a combination of stable isotopes and optical tracers to investigate fate and transport of nitrogen and carbon sources in tributaries of the largest estuary in the U.S., the Chesapeake Bay. We analyzed isotopic composition of water samples from major tributaries including the Potomac River, Susquehanna River, Patuxent River, and Choptank River during routine and storm event sampling over multiple years. A positive correlation between δ15N-NO3- and δ18O-NO3- in the Potomac River above Washington D.C. suggested denitrification or biological uptake in the watershed was removing agriculturally-derived N during summer months. In contrast, the Patuxent River in Maryland showed elevated δ15N-NO3- (5 - 12 per mil) with no relationship to δ18O-NO3- suggesting the importance of wastewater sources. From the perspective of carbon sources, there were distinct isotopic values of the δ13C-POM of particulate organic matter and fluorescence excitation emission matrices (EEMS) for rivers influenced by their dominant watershed land use. EEMS showed that there were increases in the humic and fulvic fractions of dissolved organic matter during spring floods, particularly in the Potomac River. Stable isotopic values of δ13C-POM also showed rapid depletion suggesting terrestrial carbon "pulses" in the Potomac River each spring. The δ15N-POM peaked to 10 - 15 per mil each spring suggested a potential manure source or result of biological processing within the watershed. Overall, there were considerable changes in sources and transformations of nitrogen and carbon that varied across rivers and that contribute to nitrogen and carbon loads

  15. Black carbon concentrations across the tropical Atlantic boundary layer using three methods

    Science.gov (United States)

    Pohl, K.; Lohmann, R.; Cantwell, M.; Herckes, P.

    2012-12-01

    24 particulate black carbon (BC) samples were quantified using three methods: a chemo-thermal oxidation at 375°C (CTO-375), a thermal optical transition method (Sunset Method), and pyrene fluorescence loss (PFL). BC samples were taken using a high-volume air sampler aboard the R/V Endeavor during the summer of 2010 in the Equatorial Atlantic Ocean in order to sample the aeolian "hotspot" plume of aerosols that extend from the African continent. Models have shown that annual elemental carbon (EC) deposition fluxes in this area could be as high as 25μg cm-2 a-1, which may be a significant contribution to the overall carbon budget as well as climate forcing simulations. Expected BC concentrations for this area, based on a global BC inventory using the MOGUNTIA global transport model, range between 0.01-1μg/m3 depending on season. The CTO-375 processed samples were run on an IRMS to get the total organic carbon (TOC), BC concentrations, and δ13C isotope ratios. BC was detected in every sample and concentrations ranged between 0.16-9.97μg/m3. BC concentrations were highest off the coast of the US and Caribbean islands but were lower (0.16-0.26μg/m3) in the African plume sampled between 1-5°N and 21-29°W. BC comprised between 13-81% of the TOC pool and δ13C isotopes between the TOC and BC for each sample differed by no more than 3‰. The TOC and BC pools average was -28.9‰ and -28.1‰ respectively, suggesting a C4 plant origin. A different isotope trend was evident for samples 16-19 (African plume). Their δ13C average was -23.1‰ for TOC, suggesting a mostly marine origin of the organic carbon or a mix of marine with C3 and C4 plants. This supports the observed lower BC/TOC ratio in these samples (13-50%). EC concentrations determined by the Sunset Method ranged between 0-0.32μg/m3, with EC being detected in only 8 of the 24 samples. In general, EC was found above the detection limit near the United States coastline or in the "hotspot" plume off Africa

  16. Stream restoration and sewers impact sources and fluxes of water, carbon, and nutrients in urban watersheds

    Science.gov (United States)

    Pennino, Michael J.; Kaushal, Sujay S.; Mayer, Paul M.; Utz, Ryan M.; Cooper, Curtis A.

    2016-08-01

    An improved understanding of sources and timing of water, carbon, and nutrient fluxes associated with urban infrastructure and stream restoration is critical for guiding effective watershed management globally. We investigated how sources, fluxes, and flowpaths of water, carbon (C), nitrogen (N), and phosphorus (P) shift in response to differences in urban stream restoration and sewer infrastructure. We compared an urban restored stream with two urban degraded streams draining varying levels of urban development and one stream with upland stormwater management systems over a 3-year period. We found that there was significantly decreased peak discharge in response to precipitation events following stream restoration. Similarly, we found that the restored stream showed significantly lower (p exported most carbon, nitrogen, and phosphorus at relatively lower streamflow than the two more urban catchments, which exported most carbon and nutrients at higher streamflow. Annual exports of total carbon (6.6 ± 0.5 kg ha-1 yr-1), total nitrogen (4.5 ± 0.3 kg ha-1 yr-1), and total phosphorus (161 ± 15 kg ha-1 yr-1) were significantly lower in the restored stream compared to both urban degraded streams (p exports. However, nitrate isotope data suggested that 55 ± 1 % of the nitrate in the urban restored stream was derived from leaky sanitary sewers (during baseflow), statistically similar to the urban degraded streams. These isotopic results as well as additional tracers, including fluoride (added to drinking water) and iodide (contained in dietary salt), suggested that groundwater contamination was a major source of urban nutrient fluxes, which has been less considered compared to upland sources. Overall, leaking sewer pipes are a problem globally and our results suggest that combining stream restoration with restoration of aging sewer pipes can be critical to more effectively minimizing urban nonpoint nutrient sources. The sources, fluxes, and flowpaths of groundwater

  17. Nitrogen and carbon source balance determines longevity, independently of fermentative or respiratory metabolism in the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Santos, Júlia; Leitão-Correia, Fernanda; Sousa, Maria João; Leão, Cecília

    2016-04-26

    Dietary regimens have proven to delay aging and age-associated diseases in several eukaryotic model organisms but the input of nutritional balance to longevity regulation is still poorly understood. Here, we present data on the role of single carbon and nitrogen sources and their interplay in yeast longevity. Data demonstrate that ammonium, a rich nitrogen source, decreases chronological life span (CLS) of the prototrophic Saccharomyces cerevisiae strain PYCC 4072 in a concentration-dependent manner and, accordingly, that CLS can be extended through ammonium restriction, even in conditions of initial glucose abundance. We further show that CLS extension depends on initial ammonium and glucose concentrations in the growth medium, as long as other nutrients are not limiting. Glutamine, another rich nitrogen source, induced CLS shortening similarly to ammonium, but this effect was not observed with the poor nitrogen source urea. Ammonium decreased yeast CLS independently of the metabolic process activated during aging, either respiration or fermentation, and induced replication stress inhibiting a proper cell cycle arrest in G0/G1 phase. The present results shade new light on the nutritional equilibrium as a key factor on cell longevity and may contribute for the definition of interventions to promote life span and healthy aging. PMID:27072582

  18. Nitrogen and carbon source balance determines longevity, independently of fermentative or respiratory metabolism in the yeast Saccharomyces cerevisiae

    Science.gov (United States)

    Santos, Júlia; Leitão-Correia, Fernanda

    2016-01-01

    Dietary regimens have proven to delay aging and age-associated diseases in several eukaryotic model organisms but the input of nutritional balance to longevity regulation is still poorly understood. Here, we present data on the role of single carbon and nitrogen sources and their interplay in yeast longevity. Data demonstrate that ammonium, a rich nitrogen source, decreases chronological life span (CLS) of the prototrophic Saccharomyces cerevisiae strain PYCC 4072 in a concentration-dependent manner and, accordingly, that CLS can be extended through ammonium restriction, even in conditions of initial glucose abundance. We further show that CLS extension depends on initial ammonium and glucose concentrations in the growth medium, as long as other nutrients are not limiting. Glutamine, another rich nitrogen source, induced CLS shortening similarly to ammonium, but this effect was not observed with the poor nitrogen source urea. Ammonium decreased yeast CLS independently of the metabolic process activated during aging, either respiration or fermentation, and induced replication stress inhibiting a proper cell cycle arrest in G0/G1 phase. The present results shade new light on the nutritional equilibrium as a key factor on cell longevity and may contribute for the definition of interventions to promote life span and healthy aging. PMID:27072582

  19. Using ANN and EPR models to predict carbon monoxide concentrations in urban area of Tabriz

    Directory of Open Access Journals (Sweden)

    Mohammad Shakerkhatibi

    2015-09-01

    Full Text Available Background: Forecasting of air pollutants has become a popular topic of environmental research today. For this purpose, the artificial neural network (AAN technique is widely used as a reliable method for forecasting air pollutants in urban areas. On the other hand, the evolutionary polynomial regression (EPR model has recently been used as a forecasting tool in some environmental issues. In this research, we compared the ability of these models to forecast carbon monoxide (CO concentrations in the urban area of Tabriz city. Methods: The dataset of CO concentrations measured at the fixed stations operated by the East Azerbaijan Environmental Office along with meteorological data obtained from the East Azerbaijan Meteorological Bureau from March 2007 to March 2013, were used as input for the ANN and EPR models. Results: Based on the results, the performance of ANN is more reliable in comparison with EPR. Using the ANN model, the correlation coefficient values at all monitoring stations were calculated above 0.85. Conversely, the R2 values for these stations were obtained <0.41 using the EPR model. Conclusion: The EPR model could not overcome the nonlinearities of input data. However, the ANN model displayed more accurate results compared to the EPR. Hence, the ANN models are robust tools for predicting air pollutant concentrations.

  20. Effect of nitrite concentration on pit depth in carbon steel exposed to simulated radioactive waste

    International Nuclear Information System (INIS)

    The growth of pits in carbon steel exposed to dilute (0.055 M nitrate-bearing) alkaline salt solutions that simulate radioactive waste was investigated in coupon immersion tests. Most coupons were tested in the as-received condition, with the remainder having been heat treated to produce an oxide film. Nitrite, which is an established pitting inhibitor in these solutions, was present in concentrations from 0 to 0.031 M to 0.16 M; the last concentration is known to prevent pitting initiation in the test solution at the 50 degrees C test temperature. The depths of the deepest pits on coupons of particular exposure conditions were measure microscopically and were analyzed as simple, type 1 extreme value statistical distributions, to predict the deepest expected pit in a radioactive waste tank subject to the test conditions. While the growth rate of pits could not be established from these tests, the absolute value of the deepest pits predicted is of the order of 100 mils after 448 days of exposure. The data indicate that even nitrite concentrations insufficient to prevent pitting have a beneficial effect on limiting the growth of deepest pits

  1. Molten Salt-Carbon Nanotube Thermal Energy Storage for Concentrating Solar Power Systems Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Michael Schuller; Frank Little; Darren Malik; Matt Betts; Qian Shao; Jun Luo; Wan Zhong; Sandhya Shankar; Ashwin Padmanaban

    2012-03-30

    We demonstrated that adding nanoparticles to a molten salt would increase its utility as a thermal energy storage medium for a concentrating solar power system. Specifically, we demonstrated that we could increase the specific heat of nitrate and carbonate salts containing 1% or less of alumina nanoparticles. We fabricated the composite materials using both evaporative and air drying methods. We tested several thermophysical properties of the composite materials, including the specific heat, thermal conductivity, latent heat, and melting point. We also assessed the stability of the composite material with repeated thermal cycling and the effects of adding the nanoparticles on the corrosion of stainless steel by the composite salt. Our results indicate that stable, repeatable 25-50% improvements in specific heat are possible for these materials. We found that using these composite salts as the thermal energy storage material for a concentrating solar thermal power system can reduce the levelized cost of electricity by 10-20%. We conclude that these materials are worth further development and inclusion in future concentrating solar power systems.

  2. Reduction of PM emissions from specific sources reflected on key components concentrations of ambient PM10

    Science.gov (United States)

    Minguillon, M. C.; Querol, X.; Monfort, E.; Alastuey, A.; Escrig, A.; Celades, I.; Miro, J. V.

    2009-04-01

    The relationship between specific particulate emission control and ambient levels of some PM10 components (Zn, As, Pb, Cs, Tl) was evaluated. To this end, the industrial area of Castellón (Eastern Spain) was selected, where around 40% of the EU glazed ceramic tiles and a high proportion of EU ceramic frits (middle product for the manuf