WorldWideScience

Sample records for aromatic pollutants exit

  1. Radiation degradation of aromatic pollutants exit in wastewater and ph dependence

    CERN Document Server

    Takriti, S

    2002-01-01

    The effect of gamma radiation on the degradation of phenol (hydroxybenzene), resorcinol (1,3 dihydroxybenzen) and hydroquinone (1,4 dihydroxybenzen) exit in waste water was investigated. The concentrations of these pollutants as well as the irradiated solution ph were studied. The results showed that the phenol is very resistance against the radiation doses comparing the other phenol compounds. Phenol was also a product of radiolysis of resorcinol and hydroquinone. On the other hand, the acid phase of the irradiation sample increased the degradation rate of pollutants. Spectrophotometer (UV-VIS) and chromatography (HPLC) were used to monitor the analysis of the radiation product solution. The results illustrated the existing of many substances such as organic alcohol, aldehyde, ketone and acidic functional groups as a final radiation products. The degradation of benzene, monochlorobenzene (CB) and 1,2 dichlorobenzene (1,2 DCB) exit in waste water by gamma irradiation was investigated. The effect of the irradi...

  2. Radiation degradation of aromatic pollutants exit in wastewater and ph dependence

    International Nuclear Information System (INIS)

    The effect of gamma radiation on the degradation of phenol (hydroxybenzene), resorcinol (1,3 dihydroxybenzen) and hydroquinone (1,4 dihydroxybenzen) exit in waste water was investigated. The concentrations of these pollutants as well as the irradiated solution ph were studied. The results showed that the phenol is very resistance against the radiation doses comparing the other phenol compounds. Phenol was also a product of radiolysis of resorcinol and hydroquinone. On the other hand, the acid phase of the irradiation sample increased the degradation rate of pollutants. Spectrophotometer (UV-VIS) and chromatography (HPLC) were used to monitor the analysis of the radiation product solution. The results illustrated the existing of many substances such as organic alcohol, aldehyde, ketone and acidic functional groups as a final radiation products. The degradation of benzene, monochlorobenzene (CB) and 1,2 dichlorobenzene (1,2 DCB) exit in waste water by gamma irradiation was investigated. The effect of the irradiated solution composition was studied. The results showed that the benzene is very resistance against the radiation doses comparing to other chlorobenzene. However, the existence of oxidizing substances in the irradiation phase leads to increase the degradation rate of pollutants. The dechlorination of CB and 1,2 DCB that is a result of the hydrated electron reaction with studied compounds was observed. Chromatography (HPLC) and spectrophotometer (UV-VIS) were used to monitor the analysis of the radiation product solution. The results illustrated the existing of many species as a final radiation product. On the other, the irradiation phase containing scavengers such as methanol and ethanol requires large doses to decompose the pollutants, while the oxidizing phase accelerates the degradation. (author)

  3. Does toxicity of aromatic pollutants increase under remote atmospheric conditions?

    OpenAIRE

    Ana Kroflič; Miha Grilc; Irena Grgić

    2015-01-01

    Aromatic compounds contribute significantly to the budget of atmospheric pollutants and represent considerable hazard to living organisms. However, they are only rarely included into atmospheric models which deviate substantially from field measurements. A powerful experimental-simulation tool for the assessment of the impact of low- and semi-volatile aromatic pollutants on the environment due to their atmospheric aqueous phase aging has been developed and introduced for the first time. The c...

  4. Bacterial degradation of aromatic pollutants: a paradigm of metabolic versatility

    OpenAIRE

    Díaz Fernández, Eduardo

    2004-01-01

    Although most organisms have detoxification abilities (i.e mineralization, transformation and/or immobilization of pollutants), microorganisms, particularly bacteria, play a crucial role in biogeochemical cycles and in sustainable development of the biosphere. Next to glucosyl residues, the benzene ring is the most widely distributed unit of chemical structure in nature, and many of the aromatic compounds are major environmental pollutants. Bacteria have developed strategies fo...

  5. Pollutants in Hong Kong soils: polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Chung, M K; Hu, R; Cheung, K C; Wong, M H

    2007-03-01

    An extensive soil survey was carried out to study the polycyclic aromatic hydrocarbon (PAH) contaminations in 138 soil samples collected throughout Hong Kong. Results demonstrated that there were low levels of PAH contaminations (median of summation operator 16US EPA PAHs=140 microg kg(-1)) for all land uses (urban park, greening area, country park, rural area, restored landfill, agricultural farmland, orchard farm, crematorium, industrial and near highway area). However, localized hotspots were identified with summation operator 16PAH concentrations as high as 19,500 microg kg(-1) in one urban park. These findings were also confirmed by multivariate analysis. Comparison of PAH profiles showed a widespread domination of its 4-ring member. The major contribution was vehicular emissions from petroleum, and however at the hotspots, the improper disposal of used motor oils. In general, the pollution levels for all the land uses were below the recommended values for residential and general purposes stated in soil quality guidelines such as Netherlands and Denmark except certain identified hotspots. The potential health hazards imposed by these hotspots were alarming, and their existence (3 out of 138 samples) suggested that sole monitoring of atmospheric PAHs may not adequately address the hidden risks to human in urban city. PMID:17109918

  6. Composition and source of polycyclic aromatic hydrocarbons (PAH) in oil polluted soils of Absheron peninsula

    International Nuclear Information System (INIS)

    The objectives of this study were to compare of polycyclic aromatic hydrocarbons concentration in oil, oil polluted soils and clean area in Absheron peninsula, which were never done before. Above 30 soils samples were analyzed for fifteen individual polycyclic aromatic hydrocarbons (PAH) on HPLC (high performance liquid chromatography) and were identified on GC/MS (chromatography/mass spectrometry). The rations of individual PAH in soil and blank sample were determined and source of origin polycyclic aromatic hydrocarbons was identified.

  7. Molecular comparison of cultivable protozoa from a pristine and a polycyclic aromatic hydrocarbon polluted site

    OpenAIRE

    Lara, Enrique; Berney, Cédric; Ekelund, Flemming; Harms, Hauke; Chatzinotas, Antonis

    2010-01-01

    We compared the abundance and diversity of cultivable protozoa (flagellates and amoebae) in a polycyclic aromatic hydrocarbon (PAH) polluted soil and an unpolluted control, by isolating and cultivating clonal strains. The number of cultivable protozoa was higher in the polluted soil; however, the polluted soil displayed an impoverished community, dominated by certain taxa, such as Acanthamoeba sp. We isolated a total of 31 protozoan strains to characterize them morphologically and by 18S rRNA...

  8. Microbial degradation of street dust polycyclic aromatic hydrocarbons in microcosms simulating diffuse pollution of urban soil

    DEFF Research Database (Denmark)

    Johnsen, Anders R; de Lipthay, Julia R; Sørensen, Søren J;

    2006-01-01

    Diffuse pollution with polycyclic aromatic hydrocarbons (PAHs) of topsoil in urban regions has caused increasing concerns in recent years. We simulated diffuse pollution of soil in microcosms by spiking sandy topsoil (A-horizon) and coarse, mineral subsoil (C-horizon) with street dust (PM63...... the persistence and low bioaccessibility of 5- and 6-ring PAHs in diffusely polluted soil.......) isolated from municipal street sweepings from central Copenhagen. The microbial communities adapted to PAH degradation in microcosms spiked with street dust in both A-horizon and C-horizon soils, in spite of low PAH-concentrations. The increased potential for PAH degradation was demonstrated on several...

  9. Molecular comparison of cultivable protozoa from a pristine and a polycyclic aromatic hydrocarbon polluted site

    DEFF Research Database (Denmark)

    Lara, E; Berney, C; Ekelund, Flemming;

    2007-01-01

    We compared the abundance and diversity of cultivable protozoa (flagellates and amoebae) in a polycyclic aromatic hydrocarbon (PAH) polluted soil and an unpolluted control, by isolating and cultivating clonal strains. The number of cultivable protozoa was higher in the polluted soil; however, the...... polluted soil displayed an impoverished community, dominated by certain taxa, such as Acanthamoeba sp. We isolated a total of 31 protozoan strains to characterize them morphologically and by 18S rRNA gene sequence analysis. This approach, i.e. combining morphological and molecular information had the...

  10. Biological monitoring of polycyclic aromatic hydrocarbon exposure in a highly polluted area of Poland.

    OpenAIRE

    Ovrebø, S; Fjeldstad, P E; Grzybowska, E; Kure, E H; Chorazy, M; Haugen, A

    1995-01-01

    Air pollution in Poland and particularly in Silesia is among the worst in Europe. Many coal mines and coke oven plants are located in this area, representing a major source of carcinogenic polycyclic aromatic hydrocarbons (PAHs). We quantitated the PAH exposure level in air samples using personal sampling devices, collected urine samples from the same individuals, and measured 1-hydroxypyrene with high performance liquid chromatography. Samples were collected twice, once in February and once ...

  11. Biotransformation of Trichoderma spp. and Their Tolerance to Aromatic Amines, a Major Class of Pollutants

    OpenAIRE

    Cocaign, Angélique; Bui, Linh-Chi; Silar, Philippe; Chan Ho Tong, Laetitia; Busi, Florent; Lamouri, Aazdine; Mougin, Christian; Rodrigues-Lima, Fernando; Dupret, Jean-Marie; Dairou, Julien

    2013-01-01

    Trichoderma spp. are cosmopolitan soil fungi that are highly resistant to many toxic compounds. Here, we show that Trichoderma virens and T. reesei are tolerant to aromatic amines (AA), a major class of pollutants including the highly toxic pesticide residue 3,4-dichloroaniline (3,4-DCA). In a previous study, we provided proof-of-concept remediation experiments in which another soil fungus, Podospora anserina, detoxifies 3,4-DCA through its arylamine N-acetyltransferase (NAT), a xenobiotic-me...

  12. Biodegradation, bioaccessibility, and genotoxicity of diffuse polycyclic aromatic hydrocarbon (PAH) pollution at a motorway site

    DEFF Research Database (Denmark)

    Johnsen, A.R.; de Lipthay, J.R.; Reichenberg, F.;

    2006-01-01

    Diffuse pollution of surface soil with polycyclic aromatic hydrocarbons (PAHs) is problematic in terms of the large areas and volumes of polluted soil. The levels and effects of diffuse PAH pollution at a motorway site were investigated. Surface soil was sampled with increasing distance from the...... most polluted samples close to the pavement. Hydroxypropyl-beta-cyclodextrin extraction of soil PAHs, as a direct estimate of the bioaccessibility, indicated that only 1-5% of the PAHs were accessible to soil bacteria. This low bioaccessibility is suggested to be due to sorption to traffic soot...... asphalt pavement and tested for total amounts of PAHs, amounts of bioaccessible PAHs, total bacterial populations, PAH degrader populations, the potential for mineralization of C-14-PAHs, and mutagenicity. Elevated PAH concentrations were found in the samples taken 1-8 m from the pavement. Soil sampled at...

  13. Distribution and origin sources of Polycyclic Aromatic Hydrocarbons (PAHs) pollution in sediment of Sarawak coastal area

    International Nuclear Information System (INIS)

    Alkyl and parent Polycyclic Aromatic Hydrocarbons (PAHs) compounds in marine sediment sample collected from ten locations along Sarawak coastal areas were extracted and analyzed by using gas chromatography-mass spectrometry. The source identification of PAH pollution in marine sediment of Sarawak coastal areas were identify by ratios technique of An/ An+phen, Fl/ Fl +Py, B[a]A/ (B[a]A+Chry) and total Methyl Phen/ Phen. The total alkyl and parent PAHs concentration varies from 36.5 - 277.4 ng/ g dry weight (d.w.) with a mean concentration of 138.2 ng/ g d.w. The ratio values of PAHs pollution in marine sediment of Sarawak coastal areas are clearly indicating the PAHs pollutions are originated from petroleum (petrogenic) and petroleum combustion (pyrolytic). However, the origin sources of PAHs pollution in a few stations were uncertain due to mixing sources of PAHs. (author)

  14. City air pollution of polycyclic aromatic hydrocarbons and other mutagens: occurrence, sources and health effects

    DEFF Research Database (Denmark)

    Nielsen, T.; Ejsing Jørgensen, Hans; Larsen, J.C.;

    1996-01-01

    The presence of polycyclic aromatic hydrocarbons (PAH), mutagens and other air pollutants was investigated in a busy street in central Copenhagen and in a park area adjacent to the street. The winter concentration of benzo(a)pyrene was 4.4+/-1.2 ng/m(3) in the street air and 1.4+/-0.6 ng/m(3) in...... the city park. The atmospheric concentrations of PAH decreased in the order of: street > city background air similar to suburbs > village > open land. The traffic contribution of PAH to street air was estimated to be 90% on working days and 60% during weekends and its contribution to city background...... air was estimated to be 40%. Four different approaches to evaluate the health effects are discussed. The direct effect of PAH air pollution, and other mutagens, is considered to be a maximum of five lung cancer cases each year out of one million people....

  15. Recalcitrance of polycyclic aromatic hydrocarbons in soil contributes to background pollution

    Energy Technology Data Exchange (ETDEWEB)

    Posada-Baquero, Rosa [Instituto de Recursos Naturales y Agrobiologia de Sevilla (IRNAS), C.S.I.C., Apartado 1052, E-41080 Seville (Spain); Ortega-Calvo, Jose-Julio, E-mail: jjortega@irnase.csic.es [Instituto de Recursos Naturales y Agrobiologia de Sevilla (IRNAS), C.S.I.C., Apartado 1052, E-41080 Seville (Spain)

    2011-12-15

    The microbial accessibility of native phenanthrene and pyrene was determined in soils representing background scenarios for pollution by polycyclic aromatic hydrocarbons (PAHs). The soils were selected to cover a wide range of concentrations of organic matter (1.7-10.0%) and total PAHs (85-952 {mu}g/kg). The experiments included radiorespirometry determinations of biodegradation with {sup 14}C-labeled phenanthrene and pyrene and chemical analyses to determine the residual concentrations of the native compounds. Part of the tests relied on the spontaneous biodegradation of the chemicals by native microorganisms; another part also involved inoculation with PAH-degrading bacteria. The results showed the recalcitrance of PAHs already present in the soils. Even after extensive mineralization of the added {sup 14}C-PAHs, the concentrations of native phenanthrene and pyrene did not significantly decrease. We suggest that aging processes operating at background concentrations may contribute to recalcitrance and, therefore, to ubiquitous pollution by PAHs in soils. - Highlights: > Background PAHs in soils are highly resistant to biodegradation. > Recalcitrance occurs even after inoculation with specialized microorganisms. > Recalcitrance is caused by a low bioaccessibility and aging. > Time (aging) seems a relevant factor causing recalcitrance. > Recalcitrance can explain ubiquitous PAH background pollution. - Background soil PAHs are highly resistant to biodegradation.

  16. Polycyclic aromatic hydrocarbon (PAHs) pollutants in groundwater from coal gangue stack area: characteristics and origin.

    Science.gov (United States)

    Wang, X W; Zhong, N N; Hu, D M; Liu, Z Z; Zhang, Z H

    2009-01-01

    The concentrations of polycyclic aromatic hydrocarbons (PAHs) in the leachate from the gangue and 20 groundwater samples, which were collected from the 12th Coal Mine around gangue piles in Henan Province, China, were determined by SPE-GC-MS. The characteristics of PAHs pollutants in groundwater were investigated, and compared with the concentrations of PAHs in the leachate from different weathered gangues to discuss the pollution effects of PAHs from coal gangue on groundwater. The results showed that total concentrations of the 16 EPA preferentially controlled PAHs ranged from 146.9 ng/L to 1220.6 ng/L.The components of PAHs such as chrysene, benzo[a]anthracene, benzo[b + k]fluoranthene, indeno[1,2,3-c,d]-pyrene, and dibenz[a,h]anthracene were fairly high. The 2-4 rings PAHs such as naphthalene, phenanthrene, fluorene and chrysene were dominant in groundwater, which was similar to those of the leachate from the different weathered gangues. Therefore, it should be paid much more attention on the transport of lower ring numbered PAHs leached by rains from the coal mines after landfilling and dumping. Based on the spatial distribution of PAHs and the high concentrations of PAHs with 2-4 rings in groundwater and leaching samples, there might be other pollution sources of PAHs except for penetration from coal gangue into groundwater in the Pingdingshan coal mine area. PMID:19273905

  17. Polycyclic aromatic hydrocarbon (PAHs) pollutants in groundwater from coal gangue stack area: characteristics and origin

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.W.; Zhong, N.N.; Hu, D.M.; Liu, Z.Z.; Zhang, Z.H. [China University of Petrology, Beijing (China)

    2009-07-01

    The concentrations of polycyclic aromatic hydrocarbons (PAHs) in the leachate from the gangue and 20 groundwater samples, which were collected from the 12th Coal Mine around gangue piles in Henan Province, China, were determined by SPE-GC-MS. The characteristics of PAHs pollutants in groundwater were investigated, and compared with the concentrations of PAHs in the leachate from different weathered gangues to discuss the pollution effects of PAHs from coal gangue on groundwater. The results showed that total concentrations of the 16 EPA preferentially controlled PAHs ranged from 146.9 ng/L to 1220.6 ng/L. The components of PAHs such as chrysene, benzo(a) anthracene, benzo(b+k)fluoranthene, indeno(1,2,3-c,d)-pyrene, and dibenz(a,h) anthracene were fairly high. The 2-4 rings PAHs such as naphthalene, phenanthrene, fluorene and chrysene were dominant in groundwater, which was similar to those of the leachate from the different weathered gangues. Therefore, it should be paid much more attention on the transport of lower ring numbered PAHs leached by rains from the coal mines after landfilling and dumping. Based on the spatial distribution of PAHs and the high concentrations of PAHs with 2-4 rings in groundwater and leaching samples, there might be other pollution sources of PAHs.

  18. Use of antioxidant enzymes of clam Ruditapes philippinarum as biomarker to polycyclic aromatic hydrocarbon pollution

    Science.gov (United States)

    Zhu, Lin; Tang, Xuexi; Wang, Ying; Sui, Yadong; Xiao, Hui

    2016-03-01

    The typical organic pollutant polycyclic aromatic hydrocarbon (PAH) anthracene was selected as a contaminant to investigate its effects on the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in the clam Ruditapes philippinarum. The results show that SOD, CAT and GSH-Px had diff erent induction and inhibition reactions to anthracene stress, and that three diff erent organs in R. philippinarum (visceral mass, muscle tissue and mantle) had diff erent sensitivities to anthracene stress. This study suggest that SOD activities of the visceral mass, CAT activitities of the mantle and the visceral mass, and GSH-Px activity of the muscle tissue could be used as sensitive indicators of anthracene stress in R. philippinarum.

  19. Diversity of ndo genes in mangrove sediments exposed to different sources of polycyclic aromatic hydrocarbon pollution.

    Science.gov (United States)

    Gomes, Newton C Marcial; Borges, Ludmila R; Paranhos, Rodolfo; Pinto, Fernando N; Krögerrecklenfort, Ellen; Mendonça-Hagler, Leda C S; Smalla, Kornelia

    2007-11-01

    Polycyclic aromatic hydrocarbon (PAH) pollutants originating from oil spills and wood and fuel combustion are pollutants which are among the major threats to mangrove ecosystems. In this study, the composition and relative abundance in the sediment bacterial communities of naphthalene dioxygenase (ndo) genes which are important for bacterial adaptation to environmental PAH contamination were investigated. Three urban mangrove sites which had characteristic compositions and levels of PAH compounds in the sediments were selected. The diversity and relative abundance of ndo genes in total community DNA were assessed by a newly developed ndo denaturing gradient gel electrophoresis (DGGE) approach and by PCR amplification with primers targeting ndo genes with subsequent Southern blot hybridization analyses. Bacterial populations inhabiting sediments of urban mangroves under the impact of different sources of PAH contamination harbor distinct ndo genotypes. Sequencing of cloned ndo amplicons comigrating with dominant DGGE bands revealed new ndo genotypes. PCR-Southern blot analysis and ndo DGGE showed that the frequently studied nah and phn genotypes were not detected as dominant ndo types in the mangrove sediments. However, ndo genotypes related to nagAc-like genes were detected, but only in oil-contaminated mangrove sediments. The long-term impact of PAH contamination, together with the specific environmental conditions at each site, may have affected the abundance and diversity of ndo genes in sediments of urban mangroves. PMID:17905873

  20. Ten-year Pollution Characteristics of Particulate-associated Polycyclic Aromatic Hydrocarbons in Beijing, China

    Science.gov (United States)

    Zhu, Xianlei; Deng, Changjiang; Biandan, Luobu; Fu, Xianqiang; Mu, Xilong

    2015-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are well-known air pollutants of health concern. However, they are not listed as routinely measured pollutants in China, in spite of benzo[a]pyrene (BaP) being included in the National Ambient Air Quality Standard (NAAQS). Thus, very limited continuous measurements are available for PAHs, which would hinder the understanding of long-term pollution characteristics of PAHs in context of rapid development of economy and intensive urbanization in China. To investigate annual variation and its causes of airborne particulate-associated PAHs, a total of 18 PAHs (including 16 USEPA priority species) in PM10 and PM2.5 were measured in Beijing, the capital and one of megacities of China, for a decade (from the year of 2004 to 2013) with meteorological data simultaneously recorded. The long-term measurements of PAHs showed significant annual and seasonal variations for the total concentration of PAHs (ΣPAH18) and individual PAH species. The ΣPAH18 in PM10 was highest in 2010 and lowest in 2006. Likewise, the ΣPAH18 in PM2.5 reached the highest level in 2010 and dropped to the lowest level in 2005. The annual concentration varied insignificantly for 2- and 3-ring PAHs, were relatively high in the year of 2004, 2007 and 2010 for 4-ring PAHs, and increased gradually with year for 5- to 7-ring PAHs, the markers of motor vehicle emission. As for seasonal variation, the concentrations in winter (heating period) was higher than those in summer, while concentrations in spring and autumn ranked in the middle. As for BaP, one of criteria pollutants, its concentration exceeded NAAQS of China in winter. Source apportionment by factor analysis suggested the contributions of coal combustion, vehicle emissions, fugitive dust and straw burning. Especially, the great contributions of coal combustion and vehicle emission were also supported by diagnostic ratios. The backward trajectories showed air mass crossing polluted cities and transporting in low

  1. Aromatic compound emissions from municipal solid waste landfill: Emission factors and their impact on air pollution

    Science.gov (United States)

    Liu, Yanjun; Lu, Wenjing; Guo, Hanwen; Ming, Zhongyuan; Wang, Chi; Xu, Sai; Liu, Yanting; Wang, Hongtao

    2016-08-01

    Aromatic compounds (ACs) are major components of volatile organic compounds emitted from municipal solid waste (MSW) landfills. The ACs emissions from the working face of a landfill in Beijing were studied from 2014 to 2015 using a modified wind tunnel system. Emission factors (EFs) of fugitive ACs emissions from the working face of the landfill were proposed according to statistical analyses to cope with their uncertainty. And their impacts on air quality were assessed for the first time. Toluene was the dominant AC with an average emission rate of 38.8 ± 43.0 μg m-2 s-1 (at a sweeping velocity of 0.26 m s-1). An increasing trend in AC emission rates was observed from 12:00 to 18:00 and then peaked at 21:00 (314.3 μg m-2 s-1). The probability density functions (PDFs) of AC emission rates could be classified into three distributions: Gaussian, log-normal, and logistic. EFs of ACs from the working face of the landfill were proposed according to the 95th percentile cumulative emission rates and the wind effects on ACs emissions. The annual ozone formation and secondary organic aerosol formation potential caused by AC emissions from landfills in Beijing were estimated to be 8.86 × 105 kg year-1 and 3.46 × 104 kg year-1, respectively. Toluene, m + p-xylene, and 1,3,5-trimethylbenzene were the most significant contributors to air pollution. Although ACs pollutions from landfills accounts for less percentage (∼0.1%) compared with other anthropogenic sources, their fugitive emissions which cannot be controlled efficiently deserve more attention and further investigation.

  2. Dechlorination pathways of diverse chlorinated aromatic pollutants conducted by Dehalococcoides sp. strain CBDB1

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Gui-Ning [School of Environmental Science and Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou 510006 (China); Department of Environmental Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 (United States); School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Tao, Xue-Qin [School of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225 (China); Huang, Weilin [Department of Environmental Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 (United States); Dang, Zhi, E-mail: chzdang@scut.edu.cn [School of Environmental Science and Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); Li, Zhong [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Liu, Cong-Qiang [The State Key Lab of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China)

    2010-05-15

    Dechlorination of chlorinated aromatic pollutants (CAPs) has become a major issue in recent decades. This paper reported a theoretical indicator for predicting the reductive dechlorination pathways of polychlorinated dibenzo-p-dioxins (PCDDs), chlorobenzenes and chlorophenols transformed by Dehalococcoides sp. strain CBDB1. Density functional theory (DFT) calculations were carried out at the B3LYP/6-31G(d) level for all related CAPs and Mulliken atomic charges on chlorine atoms (Q{sub Cl(n)}) were adopted as the probe of the dechlorination reaction activity. Q{sub Cl(n)} can consistently indicate the main dechlorination daughter products of PCDDs, chlorobenzenes and chlorophenols conducted by strain CBDB1. The dechlorination reaction favors elimination of the chlorine atoms having greater Q{sub Cl(n)} values. The chlorine atom with the greatest Q{sub Cl(n)} value tends preferentially to be eliminated, whereas the chlorine atom with the smallest Q{sub Cl(n)} value tends unlikely to be eliminated or does not react at all. For a series of compounds having similar structure, the maximal Q{sub Cl(n)} of each molecular can be used to predict the possibility of its daughter product(s). In addition, the difference ({Delta}Q{sub Cl(n)}) between the maximal Q{sub Cl(n)} and the next maximal Q{sub Cl(n)} of the same molecule can be used to assess the possibility of formation of multiple dechlorination products.

  3. Decontamination of metals and polycyclic aromatic hydrocarbons from slag-polluted soil.

    Science.gov (United States)

    Bisone, Sara; Mercier, Guy; Blais, Jean-François

    2013-01-01

    Metallurgy is an industrial activity that is one of the largest contributors to soil contamination by metals. This contamination is often associated with organic compound contamination; however, little research has been aimed at the development of simultaneous processes for decontamination as opposed to treatments to heavy metals or organic compounds alone. This paper presents an efficient process to decontaminate the soils polluted with smelting by-products rich in Cu, Zn and polycyclic aromatic hydrocarbons (PAHs). A simultaneous treatment for metals and PAHs was also tested. The process is mainly based on physical techniques, such as crushing, gravimetric separation and attrition. For the finest particle size fractions, an acid extraction with H2SO4 was used to remove metals. The PAH removal was enhanced by adding surfactant during attrition. The total metal removals varied from 49% to 73% for Cu and from 43% to 63% for Zn, whereas a removal yield of 92% was measured for total PAHs. Finally, a technical-economic evaluation was done for the two processes tested. PMID:24527625

  4. Global atmospheric emissions and transport of polycyclic aromatic hydrocarbons: Evaluation of modeling and transboundary pollution

    Science.gov (United States)

    Shen, Huizhong; Tao, Shu

    2014-05-01

    Global atmospheric emissions of 16 polycyclic aromatic hydrocarbons (PAHs) from 69 major sources were estimated for a period from 1960 to 2030. Regression models and a technology split method were used to estimated country and time specific emission factors, resulting in a new estimate of PAH emission factor variation among different countries and over time. PAH emissions in 2007 were spatially resolved to 0.1° × 0.1° grids based on a newly developed global high-resolution fuel combustion inventory (PKU-FUEL-2007). MOZART-4 (The Model for Ozone and Related Chemical Tracers, version 4) was applied to simulate the global tropospheric transport of Benzo(a)pyrene, one of the high molecular weight carcinogenic PAHs, at a horizontal resolution of 1.875° (longitude) × 1.8947° (latitude). The reaction with OH radical, gas/particle partitioning, wet deposition, dry deposition, and dynamic soil/ocean-air exchange of PAHs were considered. The simulation was validated by observations at both background and non-background sites, including Alert site in Canadian High Arctic, EMEP sites in Europe, and other 254 urban/rural sites reported from literatures. Key factors effecting long-range transport of BaP were addressed, and transboundary pollution was discussed.

  5. Extraction of polycyclic aromatic hydrocarbons from polluted soils with binary and ternary supercritical phases

    International Nuclear Information System (INIS)

    The paper describes how supercritical fluid extractions (SFE) using carbon dioxide and modifiers (n-hexane, cyclohexane, toluene, methyl tert-butyl ether, methoxybenzene, dichloromethane, propanone, pyridine, methanol) as well as modifier mixtures (methanol-containing diethylamide, 2-aminoethan-1-ol, acetic acid) were performed to extract polycyclic aromatic hydrocarbons (PAHs) from real environmental samples polluted to a minor extent by mineral oil products and highly contaminated by brown coal tar. Comparing the results with those from Soxhlet extraction utilizing dichloromethane and SFE using pure carbon dioxide show that acidic or basic co-solvents give the highest PAH yields. Extraction efficiency decreases with reduced polarity of the modifier used and increases at higher concentrations of co-solvent. To explain the SFE results, several mechanisms of disruption of matrix-PAH interactions are considered: the competition between the modifier molecules and the active sites of soil's organic and inorganic matter to interact with non-covalent bondings to the analytes; and the splitting of electron donor-acceptor complexes between humic substances and PAHs induced by Lewis acids or Lewis bases

  6. Graphene-coated materials using silica particles as a framework for highly efficient removal of aromatic pollutants in water

    OpenAIRE

    Yang, Kaijie; Chen, Baoliang; Zhu, Lizhong

    2015-01-01

    The substantial aggregation of pristine graphene nanosheets decreases its powerful adsorption capacity and diminishes its practical applications. To overcome this shortcoming, graphene-coated materials (GCMs) were prepared by loading graphene onto silica nanoparticles (SiO2). With the support of SiO2, the stacked interlamination of graphene was held open to expose the powerful adsorption sites in the interlayers. The adsorption of phenanthrene, a model aromatic pollutant, onto the loaded grap...

  7. Sources of polycyclic aromatic hydrocarbons (PAHs) pollution in marine sediment from Tuanku Abdul Rahman National Park, Sabah

    International Nuclear Information System (INIS)

    The concentrations of parent and alkyl Polycyclic Aromatic Hydrocarbons (PAHs) in marine sediment samples collected from Tuanku Abdul Rahman National Park, Sabah were determined by using GC-MS. The ratio of anthracene to anthracene plus phenanthrene, fluoranthene to fluoranthene plus pyrene, benz[a]anthracene to benz[a]anthracene plus chrysene and indeno[1,2,3-cd]pyrene to indeno[1,2,3-cd]pyrene plus benzo[g,h,i]perylene, compounds were used to identify the sources of PAHs pollution. The total concentration of parent and alkyl PAHs are ranged from 121.7 to 191.5 ng/ g dry weight. The concentrations of PAHs pollution in sediments were categorised as a moderate polluted. The ratio values of PAHs compound indicate the origin source of PAHs pollutions in marine sediment sample of Tuanku Abdul Rahman National Park were originated from fossil fuel combustion (pyrolytic). (author)

  8. Pollution of Flooded Arable Soils with Heavy Metals and Polycyclic Aromatic Hydrocarbons (PAHs)

    OpenAIRE

    Ciesielczuk, Tomasz; Kusza, Grzegorz; Poluszyńska, Joanna; Kochanowska, Katarzyna

    2014-01-01

    Soils that are exposed to floodwaters because of shallow groundwater and periodical wetlands are, to a large extent, exposed to contamination by organic and inorganic compounds. These are mainly compounds that have drifted along with the inflow of heavily laden floodwater and are produced within the soil profile by the anaerobic transformation of organic matter. Heavy metals and polycyclic aromatic hydrocarbon (PAH) compounds are absorbed by the soil of the floodwaters, and moving in the soil...

  9. Pollution characteristics of polycyclic aromatic hydrocarbons (PAHs) in oily sludge from the Zhongyuan Oilfield and its peripheral soils

    Institute of Scientific and Technical Information of China (English)

    KUANG Shaoping; XU Zhong

    2009-01-01

    The purpose of this study is to determine the degree of contamination caused by polycyclic aromatic hydrocarbons (PAHs) in oily sludge and soils around it in the Zhongyuan Oilfield. The contents of polycyclic aromatic hydrocarbons in oily sludge samples were determined with HPLC. The contents of PAHs of oily sludge from three different oil production plants vary from high to low in the order of the Wenming oily sludge dumping site of No. 3 Oil Production Plant (3W)>the Mazhai oily sludge dumping site of No. 3 Oil Production Plant (3M)>the Wen'er oily sludge dumping site of No. 4 Oil Production Plant (4W). Naphthalene, acenaphthylene, acenaphthene, fluorine and phenanthrene are the major pollutants of PAHs in oily sludge. The contents of PAHs in soil samples around the oily sludge dumping sites vary widely from 434.49 to 2408.8 ng/g. Naphthalene, acenaphthene, fluorine, phenanthrene and pyrene are the characteristic factors of PAHs in soil samples of 3M and 3W, and naphthalene, acenaphthene, fluorine and phenanthrene are the characteristic factors of PAHs in soil samples of 4W. According to these data and the ratios of Fl/Py, PAHs in oily sludge samples come mainly from petrogenic sources, and soil samples are divided into petrogenic soil samples and mixed-source soil samples, and both petrogenic and pyrogenic soil samples in terms of the sources of PAHs. The classification by Nemero index P indicates that soils around the oily sludge dumping sites have been seriously polluted.

  10. Pollution and pollution tolerance in the case of polycyclic aromatic hydrocarbons (PAH); Belastung durch Polyzyklische aromatische Kohlenwasserstoffe (PAK)

    Energy Technology Data Exchange (ETDEWEB)

    Renger, M.; Mekiffer, B. [Technische Univ. Berlin (Germany). Inst. fuer Oekologie-Bodenkunde

    1997-12-31

    The purpose of the present follow-up project was to examine the contamination with polycyclic aromatic hydrocarbons (PAH) of different anthropogenic urban soils including clay soils containing demolition waste, household waste, ash, and residues from a coking plant. A further task was to analyse, or infer from other part-projects, standard soil parameters such as organic carbon content, pH, and anion levels in order to clarify any relationships between PAH contamination and the more easily determinable soil characteristics. Furthermore, the sorption behaviour for PAH of selected anthropogenic urban soils was to be characterised by means of batch experiments. [Deutsch] Im Rahmen des Anschlussvorhabens sollte die Kontamination von anthropogenen Stadtboeden- darunter Truemmerschutt-, Hausmuell-, Asche- sowie Kokereilehmboden- durch polyzyklische aromatische Kohlenwasserstoffe (PAK) untersucht werden. Zusaetzlich sollten die bodenkundlichen Standardparameter Corg, pH-Wert, Anionengehalte und KAKpot analysiert bzw. von den anderen Teilvorhaben uebernommen werden, um Zusammenhaenge zwischen der PAK-Kontamination und relativ leicht zu bestimmenden bodenkundlichen Kennwerten klaeren zu koennen. Das Sorptionsverhalten ausgewaehlter anthropogener Stadtboeden fuer PAK sollte durch Batchversuche charakterisiert werden. (orig./SR)

  11. Humoral immunosuppression in men exposed to polycyclic aromatic hydrocarbons and related carcinogens in polluted environments.

    OpenAIRE

    Szczeklik, A; Szczeklik, J; Galuszka, Z; Musial, J; Kolarzyk, E; Targosz, D

    1994-01-01

    We evaluated humoral immunity by measuring IgG, IgA, IgM, and IgE concentrations in 274 male workers in an iron foundry in Cracow, Poland. There were two groups: 199 coke oven workers and 76 cold-rolling mill workers. The groups were similar with respect to age, length of work (average 15 years), and smoking habits. Exposure to polycyclic aromatic hydrocarbons (PAHs), assessed by personal and area monitoring, ranged from 0.2 to 50 micrograms/m3 benzo[a]pyrene in coke plant workers and was of ...

  12. Effects of four aromatic organic pollutants on microbial glucose metabolism and thymidine incorporation in marine sediments

    International Nuclear Information System (INIS)

    The metabolism of D-(U-14C)glucose and the incorporation of (methyl-3H)thymidine by aerobic and anaerobic marine sediment microbes exposed to 1 to 1000 ppm anthracene, naphthalene, p,p'-dichlorodiphenyltrichloroethane, and pentachlorophenol were examined. Cell-specific rates of (14C)glucose metabolism averaged 1.7 x 10-21 and 0.5 x 10-21 mol/min per cell for aerobic and anaerobic sediment slurries, respectively; (3H)thymidine incorporation rates averaged 43 x 10-24 and 9 x 10-24 mol/min per cell for aerobic and anaerobic slurries, respectively. Aerobic sediments exposed to three of the organic pollutants for 2 to 7 days showed recovery of both activities. Anaerobic sediments showed little recovery after 2 days of pre-exposure to the pollutants. The authors conclude that (i) anaerobic sediments are more sensitive than aerobic sediments to pollutant additions; (ii) (3H)thymidine incorporation is more sensitive to pollutant additions than is (14C)glucose metabolism; and (iii) the toxicity of the pollutants increased in the following order: anthracene, p,p'-dichlorodiphenyltrichloroethane, naphthalene, and pentachlorophenol

  13. Diversity of Soil Nematodes in Areas Polluted with Heavy Metals and Polycyclic Aromatic Hydrocarbons (PAHs) in Lanzhou, China

    Science.gov (United States)

    Chen, Gen; Qin, Jie; Shi, Dazhong; Zhang, Yingmei; Ji, Weihong

    2009-07-01

    This study investigated the soil nematode community structure along the Yellow River in the Lanzhou area of China, and analyzed the impact of heavy metals (Cd, Pb, Cr, Cu, and Zn) and polycyclic aromatic hydrocarbons (PAHs) on the nematode community. Soil samples from five locations (named A-E), which were chosen for soil analysis, showed significant differences in their heavy metal content ( p nematodes (up to 41 genera) and families (up to 20) that were present. The different samples also differed significantly in the total PAH content ( p nematode ecological indicators were found to correlate with concentration of soil pollutants at all the sites tested: the maturity index (MI, in addition to plant parasites), plant parasite index (PPI), ΣMI (including all the soil nematodes), Shannon-Wiener diversity index ( H''), and Wasilewska index (WI). Disturbance to the soil environment was more severe when MI, ΣMI, and H' values were lower. The results of the study show that the abundance and structure of the soil nematode communities in the sampling locations were strongly influenced by levels of heavy metals and PAHs in the soil. They also show that the diversity index H' and the maturity index can be valuable tools for assessing the impact of pollutants on nematodes.

  14. Effects of biodiesel on emissions of regulated air pollutants and polycyclic aromatic hydrocarbons under engine durability testing

    International Nuclear Information System (INIS)

    An 80,000-km durability test was performed on two engines using diesel and biodiesel (methyl ester of waste cooking oil) as fuel in order to examine emissions resulting from the use of biodiesel. The test biodiesel (B20) was blended with 80% diesel and 20% methyl ester derived from waste cooking oil. Emissions of regulated air pollutants, including CO, HC, NOx, particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) were measured at 20,000-km intervals. The identical-model engines were installed on a standard dynamometer equipped with a dilution tunnel used to measure the pollutants. To simulate real-world driving conditions, emission measurements were made in accordance with the United States Environmental Protection Agency (USEPA) FTP transient cycle guidelines. At 0 km of the durability test, HC, CO and PM emission levels were lower for the B20 engine than those for diesel. After running for 20,000 km and longer, they were higher. However, the deterioration coefficients for these regulated air pollutants were not statistically higher than 1.0, implying that the emission factors do not increase significantly after 80,000 km of driving. Total (gaseous+particulate phase) PAH emission levels for both B20 and diesel decreased as the driving mileage accumulated. However, for the engine using B20 fuel, particulate PAH emissions increased as engine mileage increased. The average total PAH emission factors were 1097 and 1437 μg bhp h-1 for B20 and diesel, respectively. For B20, the benzo[a]pyrene equivalence emission factors were 0.77, 0.24, 0.20, 7.48, 5.43 and 14.1 μg bhp h-1 for 2-, 3-, 4-, 5-, 6-ringed and total PAHs. Results show that B20 use can reduce both PAH emission and its corresponding carcinogenic potency. (author)

  15. Reconstruction of metabolic networks in a fluoranthene-degrading enrichments from polycyclic aromatic hydrocarbon polluted soil.

    Science.gov (United States)

    Zhao, Jian-Kang; Li, Xiao-Ming; Ai, Guo-Min; Deng, Ye; Liu, Shuang-Jiang; Jiang, Cheng-Ying

    2016-11-15

    Microbial degradation of polycyclic aromatic hydrocarbons (PAHs) is the primary process of removing PAHs from environments. The metabolic pathway of PAHs in pure cultures has been intensively studied, but cooperative metabolisms at community-level remained to be explored. In this study, we determined the dynamic composition of a microbial community and its metabolic intermediates during fluoranthene degradation using high-throughput metagenomics and gas chromatography-mass spectrometry (GC-MS), respectively. Subsequently, a cooperative metabolic network for fluoranthene degradation was constructed. The network shows that Mycobacterium contributed the majority of ring-hydroxylating and -cleavage dioxygenases, while Diaphorobacter contributed most of the dehydrogenases. Hyphomicrobium, Agrobacterium, and Sphingopyxis contributed to genes encoding enzymes involved in downstream reactions of fluoranthene degradation. The contributions of various microbial groups were calculated with the PICRUSt program. The contributions of Hyphomicrobium to alcohol dehydrogenases were 62.4% in stage 1 (i.e., when fluoranthene was rapidly removed) and 76.8% in stage 3 (i.e., when fluoranthene was not detectable), respectively; the contribution of Pseudomonas were 6.6% in stage 1 and decreased to 1.2% in subsequent stages. To the best of the author's knowledge, this report describes the first cooperative metabolic network to predict the contributions of various microbial groups during PAH-degradation at community-level. PMID:27415596

  16. Soil pollution by polycyclic aromatic hydrocarbons: A comparison of two Chinese cities

    Institute of Scientific and Technical Information of China (English)

    Jin Ma; Yongzhang Zhou

    2011-01-01

    Soil samples from Huizhou and Zhanjiang,China were analyzed for 16 priority polycyclic aromatic hydrocarbons (PAHs) with harmonized sampling,sample extraction and analysis quantification methods.The concentrations and sources of PAHs in soil samples of the two cities were compared.Almost all of the PAH components were detectable in 103 soil samples.The concentrations of ΣPAHs ranged from 35.40 to 534.5 μg/kg in soil samples from Huizhou,and ranged from 9.50 to 6618.00 μg/kg in samples from Zhanjiang.Evident differences of concentrations,compositions and sources of PAHs in soils were observed between the two cities.The average concentrations of individual component and the sum of a group of PAHs in soil samples from Zhanjiang were significantly higher than those in Huizhou (P < 0.05).Phe,Flu,Pyr,Bbf and Ban were the dominant PAH components both in soil samples from Huizhou and Zhanjiang.Except for these five components,Bap,Ilp,Daa and Bgp were also the dominant PAH components in soil samples from Zhanjiang.Coal combustion and liquid fossil fuel combustion were the same sources of PAHs in the two cities with different contributions,and petroleum played a key role in PAHs release in Zhanjiang.

  17. Soil pollution by polycyclic aromatic hydrocarbons: a comparison of two Chinese cities.

    Science.gov (United States)

    Ma, Jin; Zhou, Yongzhang

    2011-01-01

    Soil samples from Huizhou and Zhanjiang, China were analyzed for 16 priority polycyclic aromatic hydrocarbons (PAHs) with harmonized sampling, sample extraction and analysis quantification methods. The concentrations and sources of PAHs in soil samples of the two cities were compared. Almost all of the PAH components were detectable in 103 soil samples. The concentrations of sigmaPAHs ranged from 35.40 to 534.5 microg/kg in soil samples from Huizhou, and ranged from 9.50 to 6618.00 microg/kg in samples from Zhanjiang. Evident differences of concentrations, compositions and sources of PAHs in soils were observed between the two cities. The average concentrations of individual component and the sum of a group of PAHs in soil samples from Zhanjiang were significantly higher than those in Huizhou (P PAH components both in soil samples from Huizhou and Zhanjiang. Except for these five components, Bap, I1p, Daa and Bgp were also the dominant PAH components in soil samples from Zhanjiang. Coal combustion and liquid fossil fuel combustion were the same sources of PAHs in the two cities with different contributions, and petroleum played a key role in PAHs release in Zhanjiang. PMID:22432289

  18. Nitrated polycyclic aromatic hydrocarbon pollution during the Shanghai World Expo 2010

    Science.gov (United States)

    Wang, W.; Jing, L.; Zhan, J.; Wang, B.; Zhang, D. P.; Zhang, H. W.; Wang, D. Q.; Yang, Y.; Zhao, J.; Sun, Y. F.; Bi, X. H.; Wang, X. T.; Feng, J. L.

    2014-06-01

    Atmospheric particulate matter with aerodynamic diameter China in 2010 when the World Expo took place. Eight nitrated polycyclic aromatic hydrocarbons (NPAHs) were analyzed. Significant reductions in individual NPAH (69-324%) and the mean ΣNPAH (about 140%) concentrations were measured during the Expo period. In order to minimize the influence from the meteorological condition, individual NPAH concentrations of 2010 Expo period were compared with those in the same time period from 2008. Significant effects from the source control measures were revealed, i.e., the individual NPAH concentration reductions ranged between 31% and 477% at the mixed residential and industrial Baoshan site, and only 0-88% at the urban Xujiahui site. The relatively high 2-nitrofluoranthene/1-nitropyrene ratio values (11-31) suggested a predominance of photochemical formation of NPAHs in the atmosphere during the Expo period. It could be concluded that the air quality during the Shanghai World Expo 2010 was benefited from the following three factors; (1) source control measures during the Expo period, i.e., prohibition of open field biomass burning in surrounding areas, (2) the three-year plan implemented from October 1, 2009, including construction sites shut-down, flue-gas desulfurization/denitrification and the vehicle upgradation and (3) the Asian monsoon which brings in clean air from the ocean during spring and summer into Shanghai.

  19. Traffic pollution using mosses as bio-accumulators of metals and polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Guidotti, M.; Lucarelli, E.; Onorati, B.; Ravaioli, G. [Presidio Multizonale di Prevenzione, Rieti (Italy); De Simone, C.; Owczarek, M. [Istituto Sperimentale per lo Studio e la Difesa del Suolo, Rieti (Italy). Sez. di Conservazione del Suolo

    2000-02-01

    This paper presents the results of an investigation aimed at determining the level of pollution caused by vehicular traffic in some urban and rural areas of Rieti city (Italy). PAHs and Pb, Mn, Cr, Cd, Al, Co, Fe, As, Ni and Zn presence was assessed and measures by analysing moss specimen coming from the above mentioned areas. Statistical analysis of such data showed a good correlation between some of the named pollutants. [Italian] Vengono presentati i risultati di un'indagine tesa a determinare i livelli di inquinamento da traffico veicolare in alcune zone urbane della citta' di Rieti con l'impiego di muschi bioaccumulatori. In campioni di muschio prelevati in diverse zone della citta' sono stat determinate concentrazioni di idrocarburi policiclici aromatici e di Pb, Mn, Cr, Cd, Al, Co, Fe, As, Ni, Zn. L'analisi statistica dei risultati mostra una stretta correlazione tra le concentrazioni di alcuni inquinanti e il livello di traffico veicolare.

  20. Remediation of inorganic contaminants and polycyclic aromatic hydrocarbons from soils polluted by municipal solid waste incineration residues.

    Science.gov (United States)

    Jobin, Philippe; Coudert, Lucie; Taillard, Vincent; Blais, Jean-Francois; Mercier, Guy

    2016-08-01

    Three soils polluted by municipal solid waste (MSW) incineration residues and containing various concentrations of Cu, Pb, Sb, Sn and Zn were treated using magnetism, gravity separation (jig and shaking table) and flotation/leaching. The process removed between 18% and 39% of the contaminants present in soil 1, between 31% and 53% of the contaminants present in soil 2 and between 42% and 56% of the contaminants present in soil 3. Polycyclic aromatic hydrocarbons were present only in soil 3, and the process removed 64% of its PAHs total content. Magnetism seemed to be the most efficient technique to remove metals from contaminated soils, followed by gravity separation and finally flotation/leaching. The global efficiency of the process was higher when the initial contaminant concentrations were lower (smaller proportions of MSW incineration residues). The estimated costs of the process, including direct and indirect costs, varied from $82 to $88 per ton of treated soil depending on the proportion of MSW incineration residues mixed with the soil. PMID:26729603

  1. Hybrid sequential treatment of aromatic hydrocarbon-polluted effluents using non-ionic surfactants as solubilizers and extractants.

    Science.gov (United States)

    Álvarez, M S; Moscoso, F; Rodríguez, A; Sanromán, M A; Deive, F J

    2014-06-01

    A treatment train combining a biological and a physical approach was investigated for the first time in order to remediate polycyclic aromatic hydrocarbons (PAHs)-polluted effluents. Given the hydrophobic nature of these contaminants, the presence of non-ionic surfactants is compulsory to allow their bioavailability. The presence of these surfactants also entails an advantage in order to ease contaminant removal by the formation of aqueous two-phase systems (ATPS). The segregation ability of environmentally benign salts such as potassium tartrate, citrate, and oxalate was discussed for extracting phenanthrene (PHE), pyrene (PYR), and benzo[a]anthracene (BaA). The biological remediation efficiency reached circa 60% for PHE and PYR, and more than 80% for BaA. The coupling of ATPS subsequent stage by using potassium citrate allowed increasing the total PAH remediation yields higher than 97% of PAH removal. The viability of the proposed solution was investigated at industrial scale by using the software tool SuperPro Designer. PMID:24759641

  2. Application of a Novel Semiconductor Catalyst, CT, in Degradation of Aromatic Pollutants in Wastewater: Phenol and Catechol

    Directory of Open Access Journals (Sweden)

    Xiao Chen

    2014-01-01

    Full Text Available Water-soluble phenol and phenolic compounds were generally removed via advanced oxidation processes. A novel semiconductor catalyst, CT, was the first-time employed in the present study to degrade phenol and catechol. The phenolic compounds (initial concentration of 88 mg L−1 were completely mineralized by the CT catalytic nanoparticles (1% within 15 days, under acidic condition and with the presence of mild UV radiation (15 w, the emitted wavelength is 254 nm and the light intensity <26 μw/cm2. Under the same reaction condition, 1% TiO2 (mixture of rutile and anatase, nanopowder, <100 nm and H2O2 had lower removal efficiency (phenol: <42%; catechol: <60%, whereas the control (without addition of catalysts/H2O2 only showed <12% removal. The processes of phenol/catechol removal by CT followed pseudo-zero-order kinetics. The aromatic structures absorbed the UV energy and passed to an excited state, which the CT worked on. The pollutants were adsorbed on the CT’s surface and oxidized via charge-transfer and hydroxyl radical generation by CT. Given low initial concentrations, a circumstance encountered in wastewater polishing, the current set-up should be an efficient and less energy- and chemical-consumptive treatment method.

  3. Household air pollution and personal exposure risk of polycyclic aromatic hydrocarbons among rural residents in Shanxi, China.

    Science.gov (United States)

    Chen, Y; Shen, G; Huang, Y; Zhang, Y; Han, Y; Wang, R; Shen, H; Su, S; Lin, N; Zhu, D; Pei, L; Zheng, X; Wu, J; Wang, X; Liu, W; Wong, M; Tao, S

    2016-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are a group of pollutants of widespread concerns. Gaseous and size-segregated particulate-phase PAHs were collected in indoor and outdoor air in rural households. Personal exposure was measured and compared to the ingestion exposure. The average concentrations of 28 parent PAHs and benzo(a)pyrene (BaP) were 9000 ± 8390 and 131 ± 236 ng/m(3) for kitchen, 2590 ± 2270 and 43 ± 95 ng/m(3) for living room, and 2800 ± 3890 and 1.6 ± 0.7 ng/m(3) for outdoor air, respectively. The mass percent of high molecular weight (HMW) compounds with 5-6 rings contributed 1.3% to total 28 parent PAHs. Relatively higher fractions of HMW PAHs were found in indoor air compared to outdoor air. Majorities of particle-bound PAHs were found in the finest PM0.25 , and the highest levels of fine PM0.25 -bound PAHs were in the kitchen using peat and wood as energy sources. The 24-h personal PAH exposure concentration was 2100 ± 1300 ng/m(3) . Considering energies, exposures to those using wood were the highest. The PAH inhalation exposure comprised up to about 30% in total PAH exposure through food ingestion and inhalation, and the population attributable fraction (PAF) for lung cancer in the region was 0.85%. The risks for inhaled and ingested intakes of PAHs were 1.0 × 10(-5) and 1.1 × 10(-5) , respectively. PMID:25808453

  4. Relationship between atmospheric pollution in the residential area and concentrations of polycyclic aromatic hydrocarbons (PAHs) in human breast milk.

    Science.gov (United States)

    Pulkrabova, Jana; Stupak, Michal; Svarcova, Andrea; Rossner, Pavel; Rossnerova, Andrea; Ambroz, Antonin; Sram, Radim; Hajslova, Jana

    2016-08-15

    Human milk is an important source of beneficial nutrients and antibodies for newborns and infants and, under certain circumstances, its analysis may provide information on mothers' and infants' exposure to various contaminants. In the presented study, we have introduced the new analytical approach for analysis of 24 highly occurring polycyclic aromatic hydrocarbons (PAHs) in this indicator matrix. The sample preparation procedure is based on an ethyl acetate extraction of milk; the transfer of analytes into an organic layer is enhanced by addition of inorganic salts, i.e. sodium chloride and magnesium sulphate. Following the clean-up of a crude extract on silica SPE columns, gas chromatography coupled to triple quadrupole mass spectrometry is used for PAH identification and quantitation. The average recoveries of targeted PAHs from spiked samples were in the range of 68-110% with repeatabilities below 30% and method quantitation limits ranging from 0.03 to 0.3ng/g lipid weight. This newly validated method was successfully applied for analyses of 324 human milk samples collected from nonsmoking women during two sampling periods (summer and winter) in two residential areas in the Czech Republic differing in atmospheric pollution by PAHs. From 24 targeted analytes 17 were detected at least in one sample. Phenantherene, fluoranthrene, pyrene and fluorene were the most abundant compounds found at average concentration of 13.81, 1.80, 0.86, and 2.01ng/g lipid weight respectively. Comparing the data from two sampling periods, in both areas higher concentrations were measured in samples collected during winter. Also in the highly industrialized locality with heavily contaminated air PAH amounts in milk were higher than in the control locality. These first data on PAH concentrations in human milk collected in the Czech Republic are comparable with measurements for nonsmoking women reported earlier in the United States but significantly lower than results from China, Turkey

  5. Vehicle fleet emissions of black carbon, polycyclic aromatic hydrocarbons, and other pollutants measured by a mobile laboratory in Mexico City

    Directory of Open Access Journals (Sweden)

    M. Jiang

    2005-01-01

    Full Text Available Black carbon (BC and polycyclic aromatic hydrocarbons (PAHs are of concern due to their effects on climate and health. The main goal of this research is to provide the first estimate of emissions of BC and particle-phase PAHs (PPAHs from motor vehicles in Mexico City. The emissions of other pollutants including carbon monoxide (CO, oxides of nitrogen (NOx, volatile organic compounds (VOCs, and particulate matter of diameter 2.5 μm and less (PM2.5 are also estimated. As a part of the Mexico City Metropolitan Area field campaign in April 2003 (MCMA-2003, a mobile laboratory was driven throughout the city. The laboratory was equipped with a comprehensive suite of gas and particle analyzers, including an aethalometer that measured BC and a photoionization aerosol sensor that measured PPAHs. While driving through traffic, the mobile lab continuously sampled exhaust plumes from the vehicles around it. We have developed a method of automatically identifying exhaust plumes, which are then used as the basis for calculation of fleet-average emissions. In the approximately 75 h of on-road sampling during the field campaign, we have identified ~30 000 exhaust measurement points that represent a variety of vehicle types and driving conditions. The large sample provides a basis for estimating fleet-average emission factors and thus the emission inventory. Motor vehicles in the Mexico City area are estimated to emit 1700±200 metric tons BC, 57±6 tons PPAHs, 1 190 000±40 000 tons CO, 120 000±3000 tons NOx, 240 000±50 000 tons VOCs, and 4400±400 tons PM2.5 per year, not including cold start emissions. The estimates for CO, NOx, and PPAHs may be low by up to 10% due to the slower response time of analyzers used to measure these species. Compared to the government's official motor vehicle emission inventory for the year 2002, the estimates for CO, NOx, VOCs, and PM2.5 are 38% lower, 23% lower, 27% higher, and 25% higher, respectively. The

  6. Construction of a plant-microbe phytoremediation system: combination of vetiver grass with a functional endophytic bacterium, Achromobacter xylosoxidans F3B, for aromatic pollutants removal.

    Science.gov (United States)

    Ho, Ying-Ning; Hsieh, Ju-Liang; Huang, Chieh-Chen

    2013-10-01

    The endophytic bacterial strain Achromobacter xylosoxidans F3B, which was able to utilize aromatic compounds as a sole carbon source, was inoculated into vetiver grass in this study. A real-time PCR detection method has been developed for confirming the stability of F3B in plants and DGGE profiles were conducted for examining the diversity of endophytes during the remediation process. These results showed that the endophytic bacteria strain F3B could maintain a stable population in plant roots without largely interfering with the diversity of native endophytes. Furthermore, the strain F3B could protect plants against toluene stress and maintain chlorophyll content of leaves, and a 30% reduction of evapotranspiration through vetiver leaves was observed. Our results demonstrate the potential to improve phytoremediation of aromatic pollutants by inoculating functional endophytic bacterial strains. PMID:23591084

  7. Exit from contract

    Directory of Open Access Journals (Sweden)

    Oren Bar-Gill

    2016-01-01

    Full Text Available Objective to study the procedure of exiting the contract its costs and benefits. Methods statistical method comparative analysis. Results free exit from contract is one of the most powerful tools for the consumer rights protection. The procedure frees consumers from bad deals and keeps businesses honest. Yet consumers often choose transactions with lockin provisions trading off exit rights for other perks. This article examines the costs and benefits of free exit as compared to the lockin alternative. According to the authors the present regulation of exit penalties in the USA is poorly tailored to address concerns about lockin particularly in light of increasingly ubiquitous marketbased solutions. The article also calls regulatory attention to loyalty rewards which are shown to be as powerful as exit penalties and equally detrimental. Scientific novelty the article reveals a paradoxical state of the law exit regulations in the USA are used most where they are needed least. Termination penalties present an obvishyous target for regulatory intervention while loyalty programs seem benign not warranting any regulatory attention. Practical significance the article is of interest for the Russian juridical science and lawmaking authorities as in Russia the issue of exiting the contract is as topical as in the USA and requires solution which would impair neither the rights of consumers nor the rights of the sellers ofnbspproducts and services. nbsp

  8. Cultivation-independent analysis reveals a shift in ciliate 18S rRNA gene diversity in a polycyclic aromatic hydrocarbon-polluted soil

    OpenAIRE

    Lara, Enrique; Berney, Cédric; Harms, Hauke; Chatzinotas, Antonis

    2010-01-01

    Using cultivation-independent methods the ciliate communities of a clay-rich soil with a 90-year record of pollution by polycyclic aromatic hydrocarbons (PAH) (4.5 g kg−1 PAH) were compared with that of a nonpolluted soil collected in its vicinity and with similar properties. A ciliate-specific set of 18S rRNA gene targeting primers was designed and used to amplify DNA extracted from both soils (surface and 20 cm depth). Four clone libraries were generated with PCR products that covered an 18...

  9. Patterns of traffic polycyclic aromatic hydrocarbon pollution in mountain areas can be revealed by lichen biomonitoring: a case study in the Dolomites (Eastern Italian Alps).

    Science.gov (United States)

    Nascimbene, Juri; Tretiach, Mauro; Corana, Federica; Lo Schiavo, Fiorella; Kodnik, Danijela; Dainese, Matteo; Mannucci, Barbara

    2014-03-15

    In mountain areas of touristic interest the evaluation of the impact of human activities is crucial for ensuring long-term conservation of ecosystem biodiversity, functions and services. This study aimed at verifying the biological impact of polycyclic aromatic hydrocarbon (PAH) emissions due to traffic along the roads leading to seven passes of the Dolomites (SE Alps), which were recently declared a UNESCO World Heritage Site. Thalli of the epiphytic lichen Pseudevernia furfuracea, collected at increasing distances from the roads, were used as biomonitors. Our study revealed a gradient of decreasing PAH pollution within 300 m from the roads. Differences among passes were evident mainly for samples collected nearest to the roads, but PAH concentrations at 300 m were almost always higher than those of undisturbed reference sites, indicating that traffic PAH pollution may impact natural ecosystems and lichen diversity at relatively long distances from the emission source. PMID:24440922

  10. Exit-strategies

    DEFF Research Database (Denmark)

    Mørck, Line Lerche; Palm, Anne-Mette; Sys Møller-Andersen, Camilla

    different empirical sources. To develop and extend an "exit-prototype" about conditions of importance for moving beyond a gang/criminal position, we have analyzed documents (from newspapers and books), involved ex-gang members, social workers and experts as co-researchers in interviews, "gang......-conferences" and in feedback-meetings, where we have discussed drafts for presentations, papers and articles. Our main goal is to produce more practice relevant and precise (theoretical and empirical) understandings of exit as well as different community anchored perspectives on how to exit/move beyond criminal...

  11. Persistent organic pollutants and polycyclic aromatic hydrocarbons in penguins of the genus Pygoscelis in Admiralty Bay - An Antarctic specially managed area.

    Science.gov (United States)

    Montone, Rosalinda C; Taniguchi, Satie; Colabuono, Fernanda I; Martins, César C; Cipro, Caio Vinícius Z; Barroso, Hileia S; da Silva, Josilene; Bícego, Márcia C; Weber, Rolf R

    2016-05-15

    Persistent organic pollutants were assessed in fat samples of the Gentoo (Pygoscelis papua), Chinstrap (Pygoscelis antarcticus) and Adélie (Pygoscelis adeliae) penguins collected during the austral summers of 2005/06 and 2006/07 in Admiralty Bay, King George Island, Antarctica. The predominant organic pollutants were PCB (114 to 1115), polycyclic aromatic hydrocarbons (PAHs) (60.1 to 238.7), HCB (<0.3 to 132.2) and BDE-47 (<1.0 to 10.7) in ng g(-1) wet weight. The mean concentrations of the majority of organic pollutants were similar among the three species of penguins. Chicks of all three species showed similar profiles of PCB congeners, with predominance of lower chlorinated compounds. The distribution of PAHs was similar in all birds, with a predominance of naphthalene and alkyl-naphthalene, which are the main constituents of arctic diesel fuel. These data contribute to the monitoring of the continued exposure to organic pollutants in the Antarctic biota. PMID:26952994

  12. A complex study of air pollution with cadmium, lead, polycyclic aromatic hydrocarbons, sulfur dioxide and black smoke in the Zasavje industrialized urban region in Slovenia

    Energy Technology Data Exchange (ETDEWEB)

    Milacic, R.; Leskovsek, H.; Dolinsek, F.; Hrcek, D. [University of Ljubljana, Ljubljana (Slovak Republic)

    1995-03-01

    Air pollution has been investigated from 1991 to 1994 in Trobovlje, Zagorje and Hrastnik, three towns in the Zasavje industrialized urban region in Slovenia. Cd and Pb were measured in aerosols continuously for three years employing direct electrothermal atomic absorption spectrometry, and polycyclic aromatic hydrocarbons (PAHs) for one year by gas chromatography and gas chromatography/mass spectrometry. In addition, SO{sub 2} and Black Smoke (BS) were monitored continuously during the period investigated. The study indicated that the concentrations of all the pollutants measured were highest in the heating seasons. In the wintertime, the average monthly concentrations of SO{sub 2} were up to 30 times higher than in the summertime, and the concentrations of BS up to 8 times higher, this increase being up to 6 times for Cd, and up to 10 times for Pb. PAHs, with the exception of naphthalene, were not detected in the summertime, while in the wintertime the presence of these carcinogenic substances was very evident. In general, the degree of pollution is comparable to other urban and industrialized regions worldwide. The results indicated the substantial decrease of air pollution during the period investigated. The main reason for the decline of SO{sub 2}, Black Smoke, Cd and PAHs pollution is the progressive change of the local heating system from coal to gas and the gradual substitution of coal in coal-fired heating stations with oil. The reason for Pb pollution decrease is a substantial reduction of the Pb content in leaded gasoline during the period investigated and in increased consumption of unleaded gasoline.

  13. Air pollution in relation to US cancer mortality rates: an ecological study; likely role of carbonaceous aerosols and polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Grant, W.B. [Sunlight Nutrients & Health Research Center SUNARC, San Francisco, CA (United States)

    2009-09-15

    There are large geographical variations of cancer mortality rates in the United States. In a series of ecological studies in the U.S., a number of risk-modifying factors including alcohol, diet, ethnic background, poverty, smoking, solar ultraviolet-B (UVB), and urban/rural residence have been linked to many types of cancer. Air pollution also plays a role in cancer risk. Cancer mortality rates averaged by state for two periods, 1950-1969 and 1970-1994, were used in multiple-linear regression analyses with respect to many, of the risk-modifying factors mentioned with the addition of an air pollution index in the form of a map of acid deposition in 1985. This index is correlated with emissions from coal-fired power plants. In addition, lung cancer mortality rates for five-Year periods from 1970-74 to 1990-94 were used in multiple linear regression analyses including air pollution and cigarette smoking. The air pollution index correlated with respiratory, digestive tract, urogenital, female, blood and skin cancer. Air pollution was estimated to account for 5% of male cancer deaths and 3% of female cancer deaths between 1970-1994. Solar UVB was inversely correlated with all these types of cancer except the respirator, skin and cervical cancer. Cigarette smoking was directly linked to lung cancer but not to other types of cancer in this study. Combustion of coal, diesel fuel and wood is the likely source of air pollution that affects cancer risk on a large scale, through production of black carbon aerosols with adsorbed polycyclic aromatic hydrocarbons.

  14. 多环芳烃污染生物修复研究进展%Advances in Polycyclic Aromatic Hydrocarbon Pollution Bio-Redemption

    Institute of Scientific and Technical Information of China (English)

    张灵利; 徐宏英; 葛晶丽

    2016-01-01

    多环芳烃(polycyclic aromatic hydrocarbon,PAHs)是一类对环境有严重危害的持久性有机污染物。具有高生物富集性、致癌性、致毒性和难降解性,修复治理 PAHs 污染环境备受国内外政府及学者的关注。目前主要采用物理、化学以及生物方法对多环芳烃污染的土壤和水体进行修复。其中生物修复是一种高效、经济和生态可承受的环保技术,具有成本低、无二次污染等优点。本文从植物修复、微生物修复以及植物-微生物联合修复方面,阐述了国内外生物修复 PAHs 污染的最新研究进展。指出了生物修复 PAHs 污染环境需要进一步解决的问题,并对未来发展趋势进行了展望。%Polycyclic aromatic hydrocarbons(PAHs)is a kind of persistent organic pollutants(pops)having serious harm to the environment,and high bio-accumulation,carcinogenicity,toxicity,and difficult to degrade,redemption and control PAHs pollution onto the environment had paid many close attentions by government and scholars both at home and abroad. At present the redemption and the control of the PAHs pollution on soil and waters mainly using chemical,and biological methods. Among them bio-redemption is a kind of high efficient,economic,and ecologically sustainable environmental technology,it has the advantages of low cost,non secondary pollution etc. The authors elaborated the latest advances in bio-redemption of PAHs pollution both at home and abroad from the aspects of phyto-redemption,microbial redemption,as well as plant-microbe joint redemption. And pointed out that bio-redemption of PAHs pollution of environment need further efforts to solve the problems,and prospected the developing trend in the future.

  15. Phytoremediation of Polycyclic Aromatic Hydrocarbons in Soils Artificially Polluted Using Plant-Associated-Endophytic Bacteria and Dactylis glomerata as the Bioremediation Plant.

    Science.gov (United States)

    Gałązka, Ann; Gałązka, Rafał

    2015-01-01

    The reaction of soil microorganisms to the contamination of soil artificially polluted with polycyclic aromatic hydrocarbons (PAHs) was evaluated in pot experiments. The plant used in the tests was cock's foot (Dactylis glomerata). Three different soils artificially contaminated with PAHs were applied in the studies. Three selected PAHs (anthracene, phenanthrene, and pyrene) were used at the doses of 100, 500, and 1000 mg/kg d.m. of soil and diesel fuel at the doses of 100, 500, and 1000 mg/kg d.m. of soil. For evaluation of the synergistic effect of nitrogen fixing bacteria, the following strains were selected: associative Azospirillum spp. and Pseudomonas stutzerii. Additionally, in the bioremediation process, the inoculation of plants with a mixture of the bacterial strains in the amount of 1 ml suspension per 500 g of soil was used. Chamber pot-tests were carried out in controlled conditions during four weeks of plant growth period. The basic physical, microbiological and biochemical properties in contaminated soils were determined. The obtained results showed a statistically important increase in the physical properties of soils polluted with PAHs and diesel fuel compared with the control and also an important decrease in the content of PAHs and heavy metals in soils inoculated with Azospirillum spp. and P. stutzeri after cock's foot grass growth. The bioremediation processes were especially intensive in calcareous rendzina soil artificially polluted with PAHs. PMID:26638532

  16. Pollution characteristics of volatile organic compounds, polycyclic aromatic hydrocarbons and phthalate esters emitted from plastic wastes recycling granulation plants in Xingtan Town, South China

    Science.gov (United States)

    Huang, De-Yin; Zhou, Shun-Gui; Hong, Wei; Feng, Wei-Feng; Tao, Liang

    2013-06-01

    With the aim to investigate the main pollution characteristics of exhaust gases emitted from plastic waste recycling granulation plants, mainly volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and phthalate esters (PAEs) were analyzed in Xingtan Town, the largest distribution center of plastic waste recycling in China. Both inside and outside the plants, the total concentrations of volatile monocyclic aromatic hydrocarbons (MAHs), PAHs and PAEs ranged from 2000 to 3000 μg m-3, 450 to 1200 ng m-3, and 200 to 1200 ng m-3, respectively. Their concentration levels inside the plants were higher than those outside the plants, and PAHs and PAEs were mainly distributed in the gas-phase. Notably, highly toxic benzo[a]pyrene (BaP) could be detected inside the plants, and harmful PAEs could be detected not only inside but also outside the plants, although PAEs are non-volatile. The exhaust gas composition and concentration were related to the plastic feedstock and granulation temperature.

  17. Diagnosis of soils polluted by aromatic hydrocarbons; Diagnostic de sols pollues par des hydrocarbures aromatiques polycycliques (HAP) a l'aide de la spectrophotometrie UV

    Energy Technology Data Exchange (ETDEWEB)

    Crone, M.

    2000-01-28

    Polycyclic aromatic hydrocarbons (PAHs) were produced by many pyrolytic or combustion processes. They were found in soils, often in high concentrations. Remediation of industrial sites contaminated by PAHs requires an initial diagnosis of the pollution. In this perspective, an analytical procedure based on UV spectrophotometry was developed and validated with about 80 soil samples. Different exploitation methods of the samples UV spectra enable to develop simple and rapid characterisation tools. A PAH UV index is proposed for the estimation of global PAH concentration. A more accurate exploitation of the spectra gives an indication on the presence or the absence of some individual PAH like benzo[a]pyrene. A maturity index based on a two wavelength approach constitutes an indicator of the potential evolution of soil contamination in natural conditions. Laboratory methodology was adapted to field analyses and a test kit was designed for this purpose. The test duration is 20 minutes. (author)

  18. A wintertime study of PM2.5-bound polycyclic aromatic hydrocarbons in Taiyuan during 2009-2013: Assessment of pollution control strategy in a typical basin region

    Science.gov (United States)

    Li, Hongyan; Guo, Lili; Cao, Runfang; Gao, Bo; Yan, Yulong; He, Qiusheng

    2016-09-01

    Taiyuan city in Shanxi province, China has been one of the top heavily polluted cities in the world for a long time with large industrial emissions and high disease burden. Many pollution control strategies have been implemented forcefully by the government in recent years in Taiyuan. To better understand the effect of the strategies and related influence factors, we studied polycyclic aromatic hydrocarbons (PAHs) in fine particulate matter (PM2.5) during heating seasons in Taiyuan from 2009 to 2013. The results showed that the concentrations of PM2.5 (70.7-477.9 μg/m3) and related total PAHs (T-PAHs, 128.7-1840.2 ng/m3) far exceeded the air quality standards issued by the Ministry of Environmental Protection of China (MEP) and were higher than those in many domestic and foreign cities in spite of the pollution control. Source apportionment by the diagnostic ratio analysis and PMF model found that coal consumption contributed the most (52.1%) to the total PM2.5-bound PAHs followed by the coking industry (27.3%) and traffic exhausts (20.6%). Significant decreases in PM2.5 and PAHs levels were found in 2013, which was probably due to the large abatement of residential coal consumption and favorable meteorological factors. Being located in the north of Taiyuan basin, the pollution in Taiyuan could be aggravated by the regional transport of coal combustion- and coking-related pollutants from other industrial development zones in the south-western basin as found by the analysis of meteorological influence and back trajectory. Although the PAHs were the lowest in 2013, the BaPeq or ILCR were the highest in that year. This should be related to the increasing vehicle numbers in Taiyuan, because vehicle exhaust tends to enrich in higher molecular weight and more toxic PAHs. Our results provided useful guidance for solving the air pollution problem for cities in a semi- or total-closed basin with coal as the major energy source such as Taiyuan.

  19. Development of eukaryotic zoospores within polycyclic aromatic hydrocarbon (PAH)-polluted environments: a set of behaviors that are relevant for bioremediation.

    Science.gov (United States)

    Sungthong, Rungroch; van West, Pieter; Cantos, Manuel; Ortega-Calvo, Jose Julio

    2015-04-01

    In this study, we assessed the development (formation, taxis and settlement) of eukaryotic zoospores under different regimes of exposure to polycyclic aromatic hydrocarbons (PAHs), which imitated environmental scenarios of pollution and bioremediation. With this aim, we used an oomycete, Pythium aphanidermatum, as a source of zoospores and two PAH-degrading bacteria (Mycobacterium gilvum VM552 and Pseudomonas putida G7). The oomycete and both bacteria were not antagonistic, and zoospore formation was diminished only in the presence of the highest bacterial cell density (10(8)-10(10) colony-forming units mL(-1)). A negative influence of PAHs on zoospore formation and taxis was observed when PAHs were exposed in combination with organic solutions and polar solvents. Co-exposure of PAHs with non-polar solvents [hexadecane (HD) and 2,2,4,4,6,8,8-heptamethylnonane (HMN)] did not affect zoospore settlement at the interfaces of the organic solvents and water. However, zoospores settled and created mycelial networks only at HD-water interfaces. Both bacteria diminished the toxic influence of PAHs on zoospore formation and taxis, and they did not interrupt zoospore settlement. The results suggest that zoospore development could be applicable for toxicity assessment of PAHs and enhancement of their bioavailability. Microbial interactions during both swimming modes and community formation at pollutant interfaces were revealed as major factors that have potential relevance to bioremediation. PMID:25617701

  20. Characterization of Polynuclear Aromatic Hydrocarbons(PAHs)Pollution in Soils from Bainyin City%白银市土壤多环芳烃污染特征

    Institute of Scientific and Technical Information of China (English)

    彭晓春; 陈志良; 董家华; 任明忠; 吴彦瑜; 白中炎; 杨兵

    2011-01-01

    选取甘肃省白银市为研究区域,采集23个具有代表性的不同功能区表层土壤样品,分析土壤样品中美国环保署规定的16种优控多环芳烃(PAHs)的含量和组分特征,并采用同分异构体比率研究其污染来源.研究表明,该区土壤中PAHs含量为64.96 ~3 043.86ng/g,远超出土壤内源性PAHs含量,有52.2% 、13.0%和21.7%的土壤样品分别达到PAHs的轻度、中度、重度污染水平.多环芳烃浓度在不同类型土壤中的含量由高到低依次为河流下游底泥>生活区>工业生产区>污灌区.白银市土壤样品中4环及4环以上高分子量的PAHs所占比例较大.源解析结果表明,该市土壤PAHs来源主要是木材、煤的燃烧和化石燃料的燃烧.%The characterizations of polynuclear aromatic hydrocarbons (PAHs) pollution in soils from Bainyin City were investigated. A total of 23 soil samples were collected from the sites representative of the region for the analysis of the contents of 16 PAHs listed in US EPA priority pollutant list. The results showed that the total concentrations of PAHs in soil samples were ranged from 64. 96 to 3 043. 86 ng/g. 52. 2% , 13.0% and 21.7% soil samples were in slight, moderate and heavy level of PAHs pollution, respectively. The average degree of PAHs occurred in various soils followed the sequence: sediment samples > urban area> industrial area>sewage irrigation area. The contents of PAHs with four and over four aromatic rings were predominant in the soil samples. Coal, wood and fossil fuels combustion were the dominant sources of PAHs in the study areas with the source apportionment.

  1. Potentiating effect of graphene nanomaterials on aromatic environmental pollutant-induced cytochrome P450 1A expression in the topminnow fish hepatoma cell line PLHC-1.

    Science.gov (United States)

    Lammel, Tobias; Boisseaux, Paul; Navas, José M

    2015-09-01

    Graphene and its derivatives are an emerging class of carbon nanomaterial with great potential for a broad range of industrial and consumer applications. However, their increasing production and use is expected to result in release of nano-sized graphene platelets into the environment, where they may interact with chemical pollutants modifying their fate and toxic potential. The objective of this study was to assess whether graphene nanoplatelets can act as vector for aromatic environmental pollutants increasing their cellular uptake and associated hazardous effects in vitro. For this purpose, cell cultures of the topminnow fish (Poeciliopsis lucida) hepatoma cell line PLHC-1 were simultaneously (and successively) exposed to graphene nanoplatelets (graphene oxide (GO) or carboxyl graphene (CXYG)) and an aryl hydrocarbon receptor (AhR) agonist (β-naphthoflavone (β-NF), benzo(k)fluoranthene (BkF) or 3,3',4,4',5,5'-hexachlorobiphenyl (PCB169)). Following exposure cytochrome P450 1A (Cyp1A) induction was assessed by measuring cyp1A mRNA expression levels using reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) and Cyp1A-dependent ethoxyresorufin-O-deethylase (EROD) activity. It was observed that pre- and co-exposure of cells to GO and CXYG nanoplatelets had a potentiating effect on β-NF, BkF, and PCB169-dependent Cyp1A induction suggesting that graphene nanoplatelets increase the effective concentration of AhR agonists by facilitating their passive diffusion into the cells by damaging the cells' plasma membrane and/or by transporting them over the plasma membrane via a Trojan horse-like mechanism. The results demonstrate the existence of combination effects between nanomaterials and environmental pollutants and stress the importance of considering these effects when evaluating their respective hazard. PMID:24706484

  2. Venture Capital Trade Sale Exits

    OpenAIRE

    Engløkk, Erik Aasprong; Haarstad, Robert Jansen; Høiby, Alexander Østebø

    2011-01-01

    Even though venture capital trade sale exits are the most common and successful exit vehicle, historically most academic attention has been given to IPO exits. This thesis takes the first steps towards opening the black box that is trade sale exits. The thesis is paper-based, and the main academic contributions belong to the four papers appended. This document opens with an introduction to the field of study as well as overall reflections in order to offer the reader a contextual background. ...

  3. New methods for determination of airborne pollutants : Focus on tetrabromobisphenol A, organophosphate triesters and polycyclic aromatic hydrocarbons

    OpenAIRE

    Tollbäck, Johanna

    2009-01-01

    The work presented in this thesis concerns the development and evaluation of new methods of sampling and analysis of organic pollutants in the indoor and outdoor environment. In Paper I, the development of a new method was reported for the determination of the brominated flame retardant tetrabromobisphenol A (TBBPA) in air using sampling with glass fiber filter and polyurethane foam (PUF), ultrasonic solvent extraction and liquid chromatography coupled to electrospray ionisation mass spectrom...

  4. Promoting Exit from Violent Extremism

    DEFF Research Database (Denmark)

    Dalgaard-Nielsen, Anja

    2013-01-01

    A number of Western countries are currently adding exit programs targeting militant Islamists to their counterterrorism efforts. Drawing on research into voluntary exit from violent extremism, this article identifies themes and issues that seem to cause doubt, leading to exit. It then provides a...

  5. Leaching of polycyclic aromatic hydrocarbons from power plant lignite ash--influence of parameters important for environmental pollution.

    Science.gov (United States)

    Pergal, Miodrag M; Relić, Dubravka; Tešić, Zivoslav Lj; Popović, Aleksandar R

    2014-03-01

    Nikola Tesla B power plant (TENT B), located at the Sava River, in Obrenovac, 50 km west from the Serbian's capital, Belgrade, is the second largest coal-fired power plant in the country, consisting of two blocks, each of 620 MW capacity. In order to investigate the threat polycyclic aromatic hydrocarbons (PAHs) from deposited coal ash, obtained by coal combustion in this power plant, can represent for the surrounding environment, samples of coal ash were submitted to extraction with river water used for transport of coal ash to the dump, as well as with water of different ionic strength and acidity. It was found that, out of 16 EPA priority PAHs, only naphthalene, acenaphthylene, fluorene, phenantrene, fluoranthene, and pyrene were found in measurable concentrations in the different extracts. Their combined concentration was around 0.1 μg/L, so they do not, in terms of leached concentrations, represent serious danger for the surrounding environment. In all cases of established (and leached) PAH compounds, changes of ionic strength, acidity, or the presence of organic compounds in river water may to some extent influence the leached concentrations. However, under the examined conditions, similar to those present in the environment, leached concentrations were not more than 50 % greater than the concentrations leached by distilled water. Therefore, water desorption is likely the most important mechanism responsible for leaching of PAH compounds from filter coal ash. PMID:24243163

  6. Comparison of Soxhlet and Shake Extraction of Polycyclic Aromatic Hydrocarbons from Coal Tar Polluted Soils Sampled in the Field

    DEFF Research Database (Denmark)

    Lindhardt, Bo; Holst, Helle; Christensen, Thomas Højlund

    1994-01-01

    This study compares three extraction methods for PAHs in coal tar polluted soil: 3-times repeated shaking of the soil with dichloromethane-methanol (1:1), Soxhlet extraction with dichloromethane, and Soxhlet extraction with dichloromethane followed by Soxhlet extraction with methanol. The...... extraction efficiencies were determined for ten selected PAHs in triplicate samples of six soils sampled at former gasworks sites. The samples covered a wide range of PAH concentrations, from 0.6 to 397 mg/kg soil. Soxhlet extraction with dichloromethane followed by Soxhlet extraction with methanol, in...

  7. Geostatistical characterization of soil pollution at industrial sites Case of polycyclic aromatic hydrocarbons at former coking plants; Caracterisation geostatistique de pollutions industrielles de sols cas des hydrocarbures aromatiques polycycliques sur d'anciens sites de cokeries

    Energy Technology Data Exchange (ETDEWEB)

    Jeannee, N.

    2001-05-15

    Estimating polycyclic aromatic hydrocarbons concentrations in soil at former industrial sites poses several practical problems on account of the properties of the contaminants and the history of site: 1)collection and preparation of samples from highly heterogeneous material, 2) high short scale variability, particularly in presence of backfill, 3) highly contrasted grades making the vario-gram inference complicated. The sampling strategy generally adopted for contaminated sites is based on the historical information. Systematic sampling recommended for geostatistical estimation is often considered to be excessive and unnecessary. Two former coking plants are used as test cases for comparing several geostatistical methods for estimating (i) in situ concentrations and (ii) the probability that they are above a pollution threshold. Several practical and methodological questions are considered: 1) the properties of various estimators of the experimental vario-gram and the validity of the results; 2) the use of soft data, such as historical information, organoleptic observations and semi-quantitative methods, with a view to improve the precision of the estimates; 3) the comparison of standard sampling strategies, taking into account vertical repartition of grades and the history of the site. Multiple analyses of the same sample give an approximation of the sampling error. Short scale sampling shows the difficulty of selecting soils in the absence of a spatial structure. Sensitivity studies are carried out to assess how densely sampled soft data can improve estimates. By using mainly existing models, this work aims at giving practical recommendations for the characterization of soil pollution. (author)

  8. Pollution level, phase distribution and health risk of polycyclic aromatic hydrocarbons in indoor air at public places of Hangzhou, China

    International Nuclear Information System (INIS)

    PAHs pollution survey in air of public places was conducted in Hangzhou, China. The most serious PAHs pollution was observed in indoor air of shopping centers and the slightest was in train stations. The molecular weight of chrysene (MW 228) appeared to be the dividing line for the PAHs with a larger or smaller distribution in the vapor or particulate phase. Concentrations of 15 PAHs on PM2.5 accounted for 71.3% of total particulate PAHs, and followed by PM2.5-10 fraction (17.6%) and >PM10 fraction (11.1%). In shopping centers and supermarkets, emission of 2-4 rings PAHs occurred from indoor sources, whereas 5-6 rings PAHs predominantly originated from transport of outdoor air. In temples, PAHs in indoor air mainly originated from incense burning. Health risks associated with the inhalation of PAHs were assessed, and naphthalene made the greatest contribution (62.4%) to the total health risks. - Concentrations of PAHs in the air of selected public places in Hangzhou correspond to 10-3 life-time lung cancer risk

  9. Bioremediation of multi-polluted soil by spent mushroom (Agaricus bisporus) substrate: Polycyclic aromatic hydrocarbons degradation and Pb availability.

    Science.gov (United States)

    García-Delgado, Carlos; Yunta, Felipe; Eymar, Enrique

    2015-12-30

    This study investigates the effect of three spent Agaricus bisporus substrate (SAS) application methods on bioremediation of soil multi-polluted with Pb and PAH from close to a shooting range with respect natural attenuation (SM). The remediation treatments involve (i) use of sterilized SAS to biostimulate the inherent soil microbiota (SSAS) and two bioaugmentation possibilities (ii) its use without previous treatment to inoculate A. bisporus and inherent microbiota (SAS) or (iii) SAS sterilization and further A. bisporus re-inoculation (Abisp). The efficiency of each bioremediation microcosm was evaluated by: fungal activity, heterotrophic and PAH-degrading bacterial population, PAH removal, Pb mobility and soil eco-toxicity. Biostimulation of the native soil microbiology (SSAS) achieved similar levels of PAH biodegradation as SM and poor soil detoxification. Bioaugmented microcosms produced higher PAH removal and eco-toxicity reduction via different routes. SAS increased the PAH-degrading bacterial population, but lowered fungal activity. Abisp was a good inoculum carrier for A. bisporus exhibiting high levels of ligninolytic activity, the total and PAH-degrading bacteria population increased with incubation time. The three SAS applications produced slight Pb mobilization (<0.3%). SAS sterilization and further A. bisporus re-inoculation (Abisp) proved the best application method to remove PAH, mainly BaP, and detoxify the multi-polluted soil. PMID:26188871

  10. Pollution level, phase distribution and health risk of polycyclic aromatic hydrocarbons in indoor air at public places of Hangzhou, China

    Energy Technology Data Exchange (ETDEWEB)

    Lu Hao [Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang, 310028 (China)], E-mail: luhaozju@163.com; Zhu Lizhong [Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang, 310028 (China)], E-mail: zlz@zju.edu.cn; Chen Shuguang [Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang, 310028 (China)], E-mail: chenshuguang@zju.edu.cn

    2008-04-15

    PAHs pollution survey in air of public places was conducted in Hangzhou, China. The most serious PAHs pollution was observed in indoor air of shopping centers and the slightest was in train stations. The molecular weight of chrysene (MW 228) appeared to be the dividing line for the PAHs with a larger or smaller distribution in the vapor or particulate phase. Concentrations of 15 PAHs on PM{sub 2.5} accounted for 71.3% of total particulate PAHs, and followed by PM{sub 2.5-10} fraction (17.6%) and >PM{sub 10} fraction (11.1%). In shopping centers and supermarkets, emission of 2-4 rings PAHs occurred from indoor sources, whereas 5-6 rings PAHs predominantly originated from transport of outdoor air. In temples, PAHs in indoor air mainly originated from incense burning. Health risks associated with the inhalation of PAHs were assessed, and naphthalene made the greatest contribution (62.4%) to the total health risks. - Concentrations of PAHs in the air of selected public places in Hangzhou correspond to 10{sup -3} life-time lung cancer risk.

  11. Pollution level, inhalation exposure and lung cancer risk of ambient atmospheric polycyclic aromatic hydrocarbons (PAHs) in Taiyuan, China

    International Nuclear Information System (INIS)

    Passive air samplers were deployed to collect both gas and particulate phase polycyclic aromatic hydrocarbons in Taiyuan between 2009 and 2010. Annual average concentrations of BaP equivalent concentration (B[a]Peq) in background, rural and urban areas were 2.90 ± 0.29, 23.2 ± 30.8 and 27.4 ± 28.1 ng/m3, respectively, with higher concentration in the winter than in other seasons. The median B[a]Peq concentrations of annual inhalation exposure were estimated to be in the range of 103–347 ng/d for all population groups in rural as well as in urban areas. The median values of incremental lifetime cancer risk (ILCR) induced by whole year inhalation exposure for all groups were basically larger than 10−6, with higher values in winter than in other seasons and in urban than in rural area. In the same season and area, the ILCR of adults was larger than other age groups and that of females was a little higher than males. - Highlights: ► The median values of ILCR were higher in winter than in other seasons. ► The median values of ILCR were higher in urban than in rural area. ► In the same season and area, the ILCR of adults was larger than other age groups. ► In the same season and area, the ILCR of females was a little higher than males. ► Exposure level and the cancer slope factor influenced the ILCR greatly. - The inhalation exposure and lung cancer risk of ambient atmospheric PAHs changed for different seasons, areas and population groups in Taiyuan, China.

  12. Polycyclic aromatic hydrocarbon (PAHs) and hopanes in stranded tar-balls on the coasts of Peninsular Malaysia: applications of biomarkers for identifying sources of oil pollution.

    Science.gov (United States)

    Zakaria, M P; Okuda, T; Takada, H

    2001-12-01

    Malaysian coasts are subjected to various threats of petroleum pollution including routine and accidental oil spill from tankers, spillage of crude oils from inland and off-shore oil fields, and run-off from land-based human activities. Due to its strategic location, the Straits of Malacca serves as a major shipping lane. This paper expands the utility of biomarker compounds, hopanes, in identifying the source of tar-balls stranded on Malaysian coasts. 20 tar-ball samples collected from the east and west coast were analyzed for hopanes and polycyclic aromatic hydrocarbons (PAHs). Four of the 13 tar-ball samples collected from the west coast of Peninsular Malaysia were identified as the Middle East crude oil (MECO) based on their biomarker signatures, suggesting tanker-derived sources significantly contributing the petroleum pollution in the Straits of Malacca. The tar-balls found on the east coast seem to originate from the offshore oil platforms in the South China Sea. The presence of South East Asian crude oil (SEACO) tar-balls on the west coast carry several plausible explanations. Some of the tar-balls could have been transported via sea currents from the east coast. The tankers carrying SEACO to other countries could have accidentally spilt the oil as well. Furthermore, discharge of tank washings and ballast water from the tankers were suggested based on the abundance in higher molecular weight n-alkanes and the absence of unresolved complex mixture (UCM) in the tar-ball samples. The other possibilities are that the tar-balls may have been originated from the Sumatran oil fields and spillage of domestic oil from oil refineries in Port Dickson and Malacca. The results of PAHs analysis suggest that all the tar-ball samples have undergone various extent of weathering through evaporation, dissolution and photooxidation. PMID:11827123

  13. Polycyclic aromatic hydrocarbons (PAHs) and hopanes in stranded tar-balls on the coasts of peninsular Malaysia: applications of biomarkers for identifying sources of oil pollution

    International Nuclear Information System (INIS)

    Malaysian coasts are subjected to various threats of petroleum pollution including routine and accidental oil spill from tankers, spillage of crude oils from inland and offshore oil fields, and run-off from land-based human activities. Due to its strategic location, the Straits of Malacca serves as a major shipping lane. This paper expands the utility of biomarker compounds, hopanes, in identifying the source of tar-balls stranded on Malaysian coasts. 20 tar-ball samples collected from the east and west coast were analysed for hopanes and polycylic aromatic hydrocarbons (PAHs). Four of the 13 tar-ball samples collected from the west coast of Peninsular Malaysia were identified as the Middle East crude oil (MECO) based on their biomarker signatures, suggesting tanker-derived sources significantly contributing the petroleum pollution in the Straits of Malacca. The tar-balls found on the east cost seem to originate from the offshore oil platforms in the South China Sea. The presence of South East Asian crude oil (SEACO) tar-balls on the west coast carry several plausible explanations. Some of the tar-balls could have been transported via sea currents from the east coast. The tankers carrying SEACO to other countries could have accidentally spilt the oil as well. Furthermore, discharge of tank washings and ballast water from the tankers were suggested based on the abundance in higher molecular weight n-alkanes and the absence of unresolved complex mixture (UCM) in the tar-ball samples. The other possibilities are that the tar-balls may have originated from the Sumatran oil fields and spillage of domestic oil from oil refineries in Port Dickson and Malacca. The results of PAHs analysis suggest that all the tar-ball samples have undergone various extent of weathering through evaporation, dissolution and photo-oxidation. (Author)

  14. Polycyclic aromatic hydrocarbons (PAHs) and hopanes in stranded tar-balls on the coasts of peninsular Malaysia: applications of biomarkers for identifying sources of oil pollution

    Energy Technology Data Exchange (ETDEWEB)

    Zakaria, Mohamad Pauzi [Universiti Putra Malaysia, Faculty of Science and Environmental Studies, Selangor (Malaysia); Okuba, Tomoaki; Takada, Hideshige [Tokyo Univ. of Agriculture and Technology, Faculty of Agriculture, Tokyo (Japan)

    2001-07-01

    Malaysian coasts are subjected to various threats of petroleum pollution including routine and accidental oil spill from tankers, spillage of crude oils from inland and offshore oil fields, and run-off from land-based human activities. Due to its strategic location, the Straits of Malacca serves as a major shipping lane. This paper expands the utility of biomarker compounds, hopanes, in identifying the source of tar-balls stranded on Malaysian coasts. 20 tar-ball samples collected from the east and west coast were analysed for hopanes and polycylic aromatic hydrocarbons (PAHs). Four of the 13 tar-ball samples collected from the west coast of Peninsular Malaysia were identified as the Middle East crude oil (MECO) based on their biomarker signatures, suggesting tanker-derived sources significantly contributing the petroleum pollution in the Straits of Malacca. The tar-balls found on the east cost seem to originate from the offshore oil platforms in the South China Sea. The presence of South East Asian crude oil (SEACO) tar-balls on the west coast carry several plausible explanations. Some of the tar-balls could have been transported via sea currents from the east coast. The tankers carrying SEACO to other countries could have accidentally spilt the oil as well. Furthermore, discharge of tank washings and ballast water from the tankers were suggested based on the abundance in higher molecular weight n-alkanes and the absence of unresolved complex mixture (UCM) in the tar-ball samples. The other possibilities are that the tar-balls may have originated from the Sumatran oil fields and spillage of domestic oil from oil refineries in Port Dickson and Malacca. The results of PAHs analysis suggest that all the tar-ball samples have undergone various extent of weathering through evaporation, dissolution and photo-oxidation. (Author)

  15. Strong Impact on the Polycyclic Aromatic Hydrocarbon (PAH)-Degrading Community of a PAH-Polluted Soil but Marginal Effect on PAH Degradation when Priming with Bioremediated Soil Dominated by Mycobacteria▿

    OpenAIRE

    Johnsen, Anders R.; Schmidt, Stine; Hybholt, Trine K.; Henriksen, Sidsel; Jacobsen, Carsten S.; Andersen, Ole

    2007-01-01

    Bioaugmentation of soil polluted with polycyclic aromatic hydrocarbons (PAHs) is often disappointing because of the low survival rate and low activity of the introduced degrader bacteria. We therefore investigated the possibility of priming PAH degradation in soil by adding 2% of bioremediated soil with a high capacity for PAH degradation. The culturable PAH-degrading community of the bioremediated primer soil was dominated by Mycobacterium spp. A microcosm containing pristine soil artificial...

  16. Exit Polls and Voter Turnout

    DEFF Research Database (Denmark)

    Andersen, Asger Lau; Jensen, Thomas

    2014-01-01

    After the 2009 referendum on a proposed change to the Danish Law of Succession, it was widely claimed that the early publication of exit poll results changed the rate of turnout and eventually the outcome. We investigate this claim and contribute to the wider debate on the implications of exit...... polls by setting up and analyzing a formal model. We find that the introduction of an exit poll influences the incentive to vote both before and after the poll is published, but the signs of the effects are generally ambiguous. The observation that exit polls influence the incentive to vote even before...... they are published is often overlooked. We show that this can lead to premature conclusions about the impact of exit polls on electoral outcomes. In particular, in cases such as the Danish referendum where it clearly appears that exit polls changed the outcome, it could well be that the outcome would...

  17. Exit Polls and Voter Turnout

    DEFF Research Database (Denmark)

    Andersen, Asger Lau; Jensen, Thomas

    We set up a model of elections or referendums with two alternatives to study how voter turnout and election outcomes are affected by the publication of exit polls on election day. We find that the introduction of an exit poll influences the incentive to vote both before and after the poll is...... published, but the signs of the effects are generally ambiguous. The fact that exit polls influence the incentive to vote before they are even published is sometimes overlooked in the debate on their desirability. We show that this can lead to premature conclusions about the impact of exit polls on election...

  18. Bacterial Degradation of Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Qing X. Li

    2009-01-01

    Full Text Available Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms.

  19. Iron-impregnated titania composites for the decomposition of low-concentration aromatic organic pollutants under UV and visible light irradiation

    Institute of Scientific and Technical Information of China (English)

    Wan-Kuen Jo; Joon Yeob Lee

    2013-01-01

    Fe-TiO2 photocatalysts with different ratios of Fe to Ti were prepared by a sol-gel process using tetra-n-butyl titanium and iron(III) nitrate as Ti and Fe sources, respectively. The photocatalytic function of the prepared composites was examined for the decomposition of low-concentration (0.1 ppm) airborne benzene, toluene, ethyl benzene, and o-xylene (BTEX). The Fe-TiO2 composites were characterized by energy dispersive X-ray spectroscopy, X-ray diffraction, UV-visible spectroscopy, and Fourier transform infrared spectroscopy. The time-series ratios of outlet to inlet concentrations of toluene, ethyl benzene, and o-xylene target chemicals, as determined by the Fe-TiO2 composites under visible light exposure, were lower than or similar to those of the reference TiO2 photocatalyst. Moreover, the time-series ratios of outlet to inlet concentrations of the three compounds, as deter-mined for the Fe-TiO2 composites, increased as the ratio of Fe to Ti increased from 0.001 to 0.010. In contrast, under UV exposure, the time-series ratios of outlet to inlet concentrations of BTEX, deter-mined for the Fe-TiO2 composites, were similar to or higher than those obtained from the reference TiO2 photocatalyst. Fe-TiO2 composites with an optimal Fe to Ti ratio could effectively be applied for the purification of low-concentration aromatic organic pollutants.

  20. Strong Impact on the Polycyclic Aromatic Hydrocarbon (PAH)-Degrading Community of a PAH-Polluted Soil but Marginal Effect on PAH Degradation when Priming with Bioremediated Soil Dominated by Mycobacteria

    DEFF Research Database (Denmark)

    Johnsen, Anders R.; Schmidt, Stine; Hybholdt, Trine K.;

    2007-01-01

    with a high capacity for PAH degradation. The culturable PAH-degrading community of the bioremediated primer soil was dominated by Mycobacterium spp. A microcosm containing pristine soil artificially polluted with PAHs and primed with bioremediated soil showed a fast, 100- to 1,000-fold increase in...... incubation. A nonprimed control microcosm containing pristine soil artificially polluted with PAHs showed only small increases in the numbers of culturable PAH degraders and no pdo1 genes. Initial PAH degradation rates were highest in the primed microcosm, but later, the degradation rates were comparable in......Bioaugmentation of soil polluted with polycyclic aromatic hydrocarbons (PAHs) is often disappointing because of the low survival rate and low activity of the introduced degrader bacteria. We therefore investigated the possibility of priming PAH degradation in soil by adding 2% of bioremediated soil...

  1. Exiting Poverty: Does Sex Matter?

    OpenAIRE

    Lori J. Curtis; Kathleen Rybczynski

    2013-01-01

    Little is understood about the factors associated with poverty duration in Canada, or which factors, if any, may affect women and men differently. Moreover, research pays scant attention to how far Canadians transition out of poverty. For example, some may exit poverty only marginally, while others exit much further above the poverty line. We investigate the determinants of poverty duration among women and men in Canada. A major contribution of this article is the examination of poverty durat...

  2. Exiting Poverty: Does Sex Matter?

    OpenAIRE

    Lori J. Curtis; Kathleen Rybczynski

    2013-01-01

    While Murphy, Zhang & Dionne (2012) report a slight decrease in the average duration of poverty spells in Canada over the past decade, little is understood about the factors associated with poverty duration in Canada, nor which factors, if any, may affect women and men differently. Moreover, research pays scant attention to how far Canadians transition out of poverty. For example, some may exit poverty only marginally while others exit to much higher incomes. We investigate the determinants o...

  3. Light-Induced Cytotoxicity of 16 Polycyclic Aromatic Hydrocarbons on the US EPA Priority Pollutant List in Human Skin HaCaT Keratinocytes: Relationship Between Phototoxicity and Excited State Properties

    OpenAIRE

    Wang, Shuguang; Sheng, Yinghong; Feng, Manliang; Leszczynski, Jerzy; Wang, Lei; Tachikawa, Hiroyasu; Yu, Hongtao

    2007-01-01

    The photocytotoxicity of 16 polycyclic aromatic hydrocarbons (PAHs) on the priority pollutant list of the United States Environmental Protection Agency (US EPA) were tested in human skin HaCaT keratinocytes. A selected PAH was mixed with HaCaT cells and irradiated with a solar simulator lamp for a dose equivalent to 5 min of outdoor sunlight and the cell viability was determined immediately and also after 24 h of incubation. For the cells without incubation after the treatments, it is found t...

  4. Primary investigation of the pollution status of polycyclic aromatic hydrocarbons (PAHs) in water and soil of Xuanwei and Fuyuan, Yunnan Province, China

    Institute of Scientific and Technical Information of China (English)

    LU JunGang; XU RenJi; ZHANG QingHua; LIU JiYan; LIAO ChunYang; WEI FuSheng

    2009-01-01

    Lung cancer incidence in Xuanwei and Fuyuan is extremely high. The air pollution, especially indoor airborne PAHs generated by burning smoky coals, has been considered as the most probable reason. The air pollution may affect drinking water and soil through dry and wet deposition. In this study, the concentrations of PAHs in water and soil samples from Xuanwei and Fuyuan were monitored to investigate the influence of atmospheric PAHs pollution on water and soil. No obvious PAHs pollution in water was found in these two areas, indicating that airborne PAHs have no apparent effect on the drinking water (well water). The smoky coal combustion from household and industry, such as the activities related to power plants, coking plants and chemical industries, is responsible for the soil PAHs pollution in these two areas. The soil pollution might be the reemission source and would pose long-term threat to the local environment and health of residents.

  5. Technological Progress, Exit and Trade

    DEFF Research Database (Denmark)

    Schröder, Philipp; Sørensen, Allan

    productivity exporters are more likely to continue to export, and market exit is typically preceded by periods of contracting market shares. We show that the simple inclusion of exogenous economy wide technological progress into the standard Melitz (2003) model generates a tractable dynamic framework that...

  6. Biodegradation of Polycyclic Aromatic Hydrocarbons

    OpenAIRE

    DEMİR, İsmail; DEMİRBAĞ, Zihni

    1999-01-01

    Polycylic aromatic hydrocarbons (PAHs), such as petroleum and petroleum derivatives, are widespread organic pollutants entering the environment, chiefly, through oil spills and incomplete combustion of fossil fuels. Since most PAHs are persist in the environment for a long period of time and bioaccumulate, they cause environmental pollution and effect biological equilibrium dramatically. Biodegradation of some PAHs by microorganisms has been biochemically and genetically investigated. Ge...

  7. Water pollution potential of mineral oils with high content of polycyclic aromatic hydrocarbons (heavy fuel oil and neutral oil extracts); Untersuchungen zur Wassergefaehrdung durch Mineraloele mit hohen Gehalten an polycyclischen aromatischen Kohlenwasserstoffen (Heizoel Schwer und Extrakte)

    Energy Technology Data Exchange (ETDEWEB)

    Albers, G. [Mobil Schmierstoff GmbH, Hamburg (Germany)

    1999-01-01

    A data base on highly aromatic mineral oils has been compiled to classify mineral oil products according to their water-pollution potential (water hazard class or Wassergefaehrdungsklasse, WGK). This activity has been undertaken through the Commission for Water Hazardous Materials (Kommission Bewertung Wassergefaehrdender Stoffe, KBwS). In this special case, highly aromatic mineral oils containing a high concentration of polycyclic aromatic hydrocarbons (Polyaromatische Kohlenwasserstoffe, PAK) were evaluated. A test method for measuring the elution potential of PAK into water was developed on petroleum products with high viscosity and high freeze point. This method was applied to determine the solubility of 23 PAK (including 16 PAK according to EPA 610 and 6 PAK according to the German drinking water regulation (Trinkwasserverordnung, TVO)) from heavy fuel oil and neutral oil extract in the aqueous phase. For the 6 PAK, according to TVO, a sum limit of 0,2 {mu}g/l in drinking water is permitted by German legislation. This limit was not exceeded in any of the water phases examined. (orig.) [Deutsch] Fuer die Einstufung von Mineraloelprodukten in die Wassergefaehrdungsklassen (WGK) durch die Kommission Bewertung Wassergefaehrdender Stoffe ist es notwendig, Basisdaten zur Verfuegung zu stellen. Im speziellen Fall handelt es sich um die Bewertung von Mineraloelen, die sich durch einen hohen Gehalt an polycyclischen aromatischen Kohlenwasserstoffen (PAK) auszeichnen. Zur Eluierbarkeit von PAK`s aus Produkten mit hoher Viskosiaet bzw. mit hohem Stockpunkt wurde eine Pruefmethode entwickelt. Diese Methode wurde zur Bestimmung der Loeslichkeit von 23 PAK`s (16 PAK`s nach EPA-Liste incl. 6 PAK`s der TVO) aus den Mineraloelen Heizoel Schwer und Neutralextrakt in der Wasserphase eingesetzt. Fuer die PAK der TVO ist in der TVO ein Summengrenzwert von 0,2 {mu}g/l Trinkwasser angegeben. Dieser Grenzwert wurde in keiner der untersuchten Wasserphasen ueberschritten. (orig.)

  8. 14 CFR 135.129 - Exit seating.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Exit seating. 135.129 Section 135.129....129 Exit seating. (a)(1) Applicability. This section applies to all certificate holders operating... certificate holder shall make the passenger exit seating determinations required by this paragraph in a...

  9. 14 CFR 121.585 - Exit seating.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Exit seating. 121.585 Section 121.585..., FLAG, AND SUPPLEMENTAL OPERATIONS Flight Operations § 121.585 Exit seating. (a)(1) Each certificate... passenger exit seating determinations required by this paragraph in a non-discriminatory manner...

  10. Exit Exam as Academic Performance Indicator

    Science.gov (United States)

    Al Ahmad, Mahmoud; Al Marzouqi, Ali H.; Hussien, Mousa

    2014-01-01

    This paper focuses on the impact of exit exams on different elements of the educational process, namely: curriculum development, students and instructors. A 50-question multiple-choice Exit Exam was prepared by Electrical Engineering (EE) faculty members covering a poll of questions from EE core courses. A copy of the Exit Exam applied during each…

  11. Aromatic graphene

    Science.gov (United States)

    Das, D. K.; Sahoo, S.

    2016-04-01

    In recent years graphene attracts the scientific and engineering communities due to its outstanding electronic, thermal, mechanical and optical properties and many potential applications. Recently, Popov et al. [1] have studied the properties of graphene and proved that it is aromatic but without fragrance. In this paper, we present a theory to prepare graphene with fragrance. This can be used as scented pencils, perfumes, room and car fresheners, cosmetics and many other useful household substances.

  12. Plasmids and aromatic degradation in Sphingomonas for bioremediation : Aromatic ring cleavage genes in soil and rhizosphere

    OpenAIRE

    SipilÀ, Timo

    2009-01-01

    Microbial degradation pathways play a key role in the detoxification and the mineralization of polyaromatic hydrocarbons (PAHs), which are widespread pollutants in soil and constituents of petroleum hydrocarbons. In microbiology the aromatic degradation pathways are traditionally studied from single bacterial strains with capacity to degrade certain pollutant. In soil the degradation of aromatics is performed by a diverse community of micro-organisms. The aim of this thesis was to study biode...

  13. The relationship between biomarkers of oxidative DNA damage, polycyclic aromatic hydrocarbon DNA adducts, antioxidant status and genetic susceptibility following exposure to environmental air pollution in humans

    Czech Academy of Sciences Publication Activity Database

    Shing, R.; Šrám, Radim; Binková, Blanka; Kalina, I.; Popov, T. A.; Georgieva, T.; Garte, S.; Taioli, E.; Farmer, P. B.

    2007-01-01

    Roč. 620, - (2007), s. 83-92. ISSN 0027-5107 Grant ostatní: EU(GB) 2000-00091; EU(GB) G0100873 Institutional research plan: CEZ:AV0Z50390512 Source of funding: R - rámcový projekt EK ; R - rámcový projekt EK Keywords : air pollution * PAHs * oxidative DNA damage Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 4.159, year: 2007

  14. Topological inflation with graceful exit

    CERN Document Server

    Marunović, Anja

    2015-01-01

    We investigate a class of models of topological inflation in which a super-Hubble-sized global monopole seeds inflation. These models are attractive since inflation starts from rather generic initial conditions, but their not so attractive feature is that, unless symmetry is again restored, inflation never ends. In this work we show that, in presence of another nonminimally coupled scalar field, that is both quadratically and quartically coupled to the Ricci scalar, inflation naturally ends, representing an elegant solution to the graceful exit problem of topological inflation. While the monopole core grows during inflation, the growth stops after inflation, such that the monopole eventually enters the Hubble radius, and shrinks to its Minkowski space size, rendering it immaterial for the subsequent Universe's dynamics. Furthermore, we find that our model can produce cosmological perturbations that source CMB temperature fluctuations and seed large scale structure statistically consistent (within one standard...

  15. A kinetic study of several aromatic compounds oxidation: applied to pollutants formation in car engines; Etude cinetique de l'oxydation de composes aromatiques: application a la formation de polluants dans les moteurs automobiles

    Energy Technology Data Exchange (ETDEWEB)

    Pengloan, G.

    2001-12-15

    Commercial fuels contain a multitude of chemical compounds. Their incomplete combustion in car engines leads to pollutants emission. The aim of this study is to improve our knowledge of oxidation kinetic mechanisms at high temperature for aromatic hydrocarbons because of their importance in fuels composition. Kinetics of benzene, toluene, ethyl-benzene and styrene combustion was studied, at equivalence ratio in the range 0.5 to 1.5, by means of two experimental apparatus: a jet-stirred reactor (JSR) and a shock tube (ST). In the JSR, reactive mixtures, diluted by N{sub 2}, were oxidized at atmospheric pressure in the temperature range 950 to 1400 K. Concentration profiles of sampled stable species were measured, at a steady residence time, by gas chromatography (GC/MS, GC/FID/TCD). In the ST, temperature and pressure ranges were higher: 1300 < T(K) < 2000, 1 < P(bar) < 20. Ignition delays were measured by recording OH emission profiles at 306 nm. A detailed kinetic reaction mechanism for the oxidation of aromatic hydrocarbons at high temperature was proposed. This mechanism includes 936 reactions and 125 species. It's based on the kinetic scheme of Ristori et al. (2001),It was further validated in the present work by modeling the ignition of benzene and toluene. Ethyl-benzene and styrene sub-mechanisms were developed. The agreement between the simulations and JSR experimental data is satisfactory. The ignition delays are well simulated. However, the modeling of concentration profiles needs improvements: defaults in the mechanism of benzene have repercussions on the predicted reactivity of ethyl-benzene and styrene which is higher than observed in the experiments. (author)

  16. Spoiled Onions: Exposing Malicious Tor Exit Relays

    OpenAIRE

    Winter, Philipp; Lindskog, Stefan

    2014-01-01

    Several hundred Tor exit relays together push more than 1 GiB/s of network traffic. However, it is easy for exit relays to snoop and tamper with anonymised network traffic and as all relays are run by independent volunteers, not all of them are innocuous. In this paper, we seek to expose malicious exit relays and document their actions. First, we monitored the Tor network after developing a fast and modular exit relay scanner. We implemented several scanning modules for detecting common attac...

  17. Seasonal Variations in Health Hazards from Polycyclic Aromatic Hydrocarbons Bound to Submicrometer Particles at Three Characteristic Sites in the Heavily Polluted Polish Region

    Directory of Open Access Journals (Sweden)

    Barbara Kozielska

    2014-12-01

    Full Text Available Suspended particles with aerodynamic diameters not greater than 1 μm (PM1 were sampled at the urban background; regional background; and urban traffic points in southern Poland. In total, 120 samples were collected between 2 August 2009 and 27 December 2010. Sixteen polycyclic aromatic hydrocarbons (PAHs were determined in each sample. The samples were collected with a high volume sampler (Digitel. Afterwards, they were chemically analyzed with a gas chromatograph equipped with a flame ionization detector (Perkin Elmer Clarus 500. The mean concentration values of the PAH sum (ΣPAH and particular PAHs; the percentages of carcinogenic PAHs in total PAHs (ΣPAHcarc/ΣPAH; carcinogenic equivalent (CEQ; mutagenic equivalent (MEQ; and TCDD-toxic equivalent (TEQ were much higher in the winter (heating season than in the summer (non-heating one. For both periods, the resulting average values obtained were significantly higher (a few; and sometimes a several dozen times higher in the researched Polish region than the values observed in other areas of the world. Such results indicate the importance of health hazards resulting from PM1 and PM1-bound PAHs in this Polish area.

  18. Molecular application for identification of polycyclic aromatic hydrocarbons degrading bacteria (PAHD) species isolated from oil polluted soil in Dammam, Saud Arabia.

    Science.gov (United States)

    Ibrahim, Mohamed M; Al-Turki, Ameena; Al-Sewedi, Dona; Arif, Ibrahim A; El-Gaaly, Gehan A

    2015-09-01

    Soil contamination with petroleum hydrocarbon products such as diesel and engine oil is becoming one of the major environmental problems. This study describes hydrocarbons degrading bacteria (PHAD) isolated from long-standing petrol polluted soil from the eastern region, Dammam, Saudi Arabia. The isolated strains were firstly categorized by accessible shape detection, physiological and biochemistry tests. Thereafter, a technique established on the sequence analysis of a 16S rDNA gene was used. Isolation of DNA from the bacterial strains was performed, on which the PCR reaction was carried out. Strains were identified based on 16S rDNA sequence analysis, As follows amplified samples were spontaneously sequenced automatically and the attained results were matched to open databases. Among the isolated bacterial strains, S1 was identified as Staphylococcus aureus and strain S1 as Corynebacterium amycolatum. PMID:26288572

  19. 14 CFR 25.807 - Emergency exits.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Emergency exits. 25.807 Section 25.807... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Emergency Provisions § 25.807 Emergency..., with landing gear extended. (6) Tailcone. This type is an aft exit from the passenger...

  20. How External Exit Exams Spur Achievement.

    Science.gov (United States)

    Bishop, John H.; Mane, Ferran; Bishop, Michael

    2001-01-01

    Compared with minimum competency tests, curriculum-based external exit exams provide better measures of students' achievement levels. Analysis of Third Mathematics and Science Study data shows that 13 year-olds from exit-exam countries are ahead of nonparticipating countries. Effects on college enrollment, job success, and test scores are…

  1. Beautiful Exit: Break Up With A Smile

    OpenAIRE

    Alajoutsijärvi, K; MÖller, K.; Tähtinen, J. (Jaana)

    1999-01-01

    This paper constructs a framework describing communication strategies available in dissolving interorganisational buyer-seller relationships. In particular, we bring in a quality aspect, as we are looking for strategies that could be labelled "beautiful exits". A beautiful exit is achieved by using a communication strategy that minimises damages occurring to the disengager, the other party and the connected network.

  2. Minimal Exit Trajectories with Optimum Correctional Manoeuvres

    Directory of Open Access Journals (Sweden)

    T. N. Srivastava

    1980-10-01

    Full Text Available Minimal exit trajectories with optimum correctional manoeuvers to a rocket between two coplaner, noncoaxial elliptic orbits in an inverse square gravitational field have been investigated. Case of trajectories with no correctional manoeuvres has been analysed. In the end minimal exit trajectories through specified orbital terminals are discussed and problem of ref. (2 is derived as a particular case.

  3. Topological inflation with graceful exit

    Science.gov (United States)

    Marunović, Anja; Prokopec, Tomislav

    2016-04-01

    We investigate a class of models of topological inflation in which a super-Hubble-sized global monopole seeds inflation. These models are attractive since inflation starts from rather generic initial conditions, but their not so attractive feature is that, unless symmetry is again restored, inflation never ends. In this work we show that, in presence of another nonminimally coupled scalar field, that is both quadratically and quartically coupled to the Ricci scalar, inflation naturally ends, representing an elegant solution to the graceful exit problem of topological inflation. While the monopole core grows during inflation, the growth stops after inflation, such that the monopole eventually enters the Hubble radius, and shrinks to its Minkowski space size, rendering it immaterial for the subsequent Universe's dynamics. Furthermore, we find that our model can produce cosmological perturbations that source CMB temperature fluctuations and seed large scale structure statistically consistent (within one standard deviation) with all available data. In particular, for small and (in our convention) negative nonminimal couplings, the scalar spectral index can be as large as ns simeq 0.955, which is about one standard deviation lower than the central value quoted by the most recent Planck Collaboration.

  4. 抚顺地区土壤中多环芳烃污染水平与风险评价%Pollution Level and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Soil in Fushun Area

    Institute of Scientific and Technical Information of China (English)

    徐天赐; 朱广钦; 付毓; 贺业菊

    2014-01-01

    在8个点位采集了抚顺地区表层土壤样品,以液相色谱法检测其多环芳烃(PAHs)含量。结果表明:土壤中PAHs 单体浓度在0.6~121.0μg/kg,以3环、4环结构为主;2家化工企业附近土壤属燃煤和煤/焦炭污染源造成的轻度污染,具一定潜在致癌性。%The soil samples were collected from 8 different locations in Fushun Area and the polycyclic aromatic hydrocarbons (PAHs ) contents were determined by high-performance liquid chromatography.The results showed that individual PAHs concentration ranged from 0.6 μg/kg to 121.0μg/kg,and among them the 3-ring and 4-ring PAHs were the dominant form.The soil samples near two chemical enterprises were slightly polluted probably by coal burning,coal and coke,and the samples showed potential carcinogenicity compared with other samples.

  5. Room evacuation through two contiguous exits

    CERN Document Server

    Sticco, I M; Dorso, C O

    2016-01-01

    Current regulations demand that at least two exits should be available for a safe evacuation during a panic situation. Although the "faster is slower" effect is expected to take place near the exits, the evacuation time will improve because of the additional exits. However, rooms having contiguous doors not always reduce the leaving time as expected. We investigated the relation between the doors separation and the evacuation performance. We found that there exists a separation distance range that does not really improve the evacuation time, or it can even worsen the process performance. To our knowledge, no attention has been given to this issue in the literature. This work reports how the pedestrians dynamics differ when the separation distance between two exit doors changes and how this affects the overall performance.

  6. Understanding Agricultural Labor Exits in Tanzania

    OpenAIRE

    McCullough, Ellen B.

    2015-01-01

    The process of economic development is embodied by rising output per agricultural worker and the exit of labor from agriculture to other sectors, which together result in rising incomes and falling incidence of poverty. This paper addresses agricultural technology's role in slowing or speeding exits of labor from agriculture in Tanzania through its effects on labor productivity. Using a structural multinomial model of occupational choice, I model households' decisions to participation in diff...

  7. Entry and exit decisions under uncertainty

    DEFF Research Database (Denmark)

    Kongsted, Hans Christian

    1996-01-01

    This paper establishes the general deterministic limit that corresponds to Dixit's model of entry and exit decisions under uncertainty. The interlinked nature of decisions is shown to be essential also in the deterministic limit. A numerical example illustrates the result......This paper establishes the general deterministic limit that corresponds to Dixit's model of entry and exit decisions under uncertainty. The interlinked nature of decisions is shown to be essential also in the deterministic limit. A numerical example illustrates the result...

  8. Contracts and Exits in Venture Capital Finance

    OpenAIRE

    Cumming, Douglas J.

    2004-01-01

    Contracts and exits from a sample of 179 investment rounds in 132 entrepreneurial firms by 17 European venture capital (VC) funds are analyzed. The data indicate the financial contracts are quite heterogeneous in terms of both the cash flow and control rights. The use of different securities by European VC funds does not depend on the definition of venture capital, and the securities used are not functional equivalents. A normative empirical analysis of exit shows the likelihoo...

  9. Biodegradation Rates of Aromatic Contaminants in Biofilm Reactors

    DEFF Research Database (Denmark)

    Arcangeli, Jean-Pierre; Arvin, Erik

    1995-01-01

    This study has shown that microorganisms can adapt to degrade mixtures of aromatic pollutants at relatively high rates in the μg/l concentration range. The biodegradation rates of the following compounds were investigated in biofilm systems: aromatic hydrocarbons, phenol, methylphenols......, chlorophenols, nitrophenol, chlorobenzenes and aromatic nitrogen-, sulphur- or oxygen-containing heterocyclic compounds (NSO-compounds). Furthermore, a comparison with degradation rates observed for easily degradable organics is also presented. At concentrations below 20-100 μg/l the degradation of the aromatic...

  10. An Entrance to Exit Polling: Strategies for Using Exit Polls as Experiential Learning Projects

    Science.gov (United States)

    Berry, Michael J.; Robinson, Tony

    2012-01-01

    Engaging students in the design, administration, and postelection analysis of an exit poll can be an excellent experiential learning activity. Lelieveldt and Rossen (2009) argue that exit polls are a "perfect teaching tool" because they provide students with a cooperative (rather than competitive) learning experience; help students better connect…

  11. 14 CFR 29.809 - Emergency exit arrangement.

    Science.gov (United States)

    2010-01-01

    ... emergency exit in a minor crash landing as a result of fuselage deformation under the ultimate inertial... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Emergency exit arrangement. 29.809 Section... Accommodations § 29.809 Emergency exit arrangement. (a) Each emergency exit must consist of a movable door...

  12. 12 CFR 611.1250 - Preliminary exit fee estimate.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Preliminary exit fee estimate. 611.1250 Section... System Institution Status § 611.1250 Preliminary exit fee estimate. (a) Preliminary exit fee estimate—terminating association. You must provide a preliminary exit fee estimate to us when you submit the plan...

  13. Jet Exit Rig Six Component Force Balance

    Science.gov (United States)

    Castner, Raymond; Wolter, John; Woike, Mark; Booth, Dennis

    2012-01-01

    A new six axis air balance was delivered to the NASA Glenn Research Center. This air balance has an axial force capability of 800 pounds, primary airflow of 10 pounds per second, and a secondary airflow of 3 pounds per second. Its primary use was for the NASA Glenn Jet Exit Rig, a wind tunnel model used to test both low-speed, and high-speed nozzle concepts in a wind tunnel. This report outlines the installation of the balance in the Jet Exit Rig, and the results from an ASME calibration nozzle with an exit area of 8 square-inches. The results demonstrated the stability of the force balance for axial measurements and the repeatability of measurements better than 0.20 percent.

  14. The Political Economy of Early Exit

    DEFF Research Database (Denmark)

    Schmitt, Carina; Starke, Peter

    2016-01-01

    Large-scale exit from the labour market began in the 1970s in many OECD countries. The literature indicates that individual early retirement decisions are facilitated by generous and accessible ‘pathways’ into retirement in the public pension system, unemployment insurance or disability benefits...... the tradable sector, against a more traditional class-based logic of welfare state policy-making. Quantitative analysis of employment outcomes in 21 countries shows that the political economy of early exit clearly rests on the sectoral politics of cost-shifting....

  15. The xenobiotic-metabolizing enzymes in Helix aspersa (snail) and Pleurozium schreberi (moss), potential bio-marker of polycyclic aromatic hydrocarbons air pollution; Les enzymes de biotransformation des xenobiotiques chez helix aspersa (escargot) et pleurozium schreberi (mousse), biomarqueurs potentiels de la pollution atmospherique par les hydrocarbures aromatiques polycycliques

    Energy Technology Data Exchange (ETDEWEB)

    Ismert, M.

    2000-12-01

    The aim of this work was to evaluate the potential value of xenobiotic-metabolizing enzymes as bio-marker of air pollution by polycyclic aromatic hydrocarbons (PAH). Using several models of PAH air pollution, we investigated their effects on cytochrome P450 (7-ethoxyresorufin O-deethylase, EROD and 7-ethoxycoumarin O-deethylase, ECOD) and glutathione-dependent enzyme activities (glutathione S-transferases, GST with 1-chloro-2,4-dinitro-benzene and 4-nitro-quinoline-1-oxide as substrates, glutathione reductase and glutathione peroxidases) in three organs of the snail Helix aspersa as well as on glutathione-dependent and antioxidant (ascorbate peroxidase and catalase) enzyme activities in the moss Pleurozium schreberi. In the first model, H. aspersa and P. schreberi were exposed to a naphthalene-saturated atmosphere during three days. While, this treatment did not provoke any variation of the enzyme activities explored in P. schreberi, it modified the level of some snail enzyme activities in an organ-dependent manner. Naphthalene exposure affected none of the tested activities in the mantle cavity-forming tissues (MCFT), but significantly decreased EROD and ECOD activities in the kidney (KD) as opposed to their increase in the digestive gland (DG). In the second model, these organisms were exposed for 8 hours to a work place where the atmosphere was essentially PAH burden. Benzo[a]pyrene was used as the PAH model compound. None of the selected enzyme activities were affected in the moss. Conversely, EROD and ECOD activities were significantly increased in the KD and DG of H. aspersa, whatever the PAH burden. Moreover, GST activities with 1-chloro-2,4-dinitro-benzene as the acceptor substrate were enhanced in the DG. In the third model, the organisms were transplanted in three urban places during one or several weeks. GST activities with both substrates were positively correlated with the level of nitrogen oxides in the digestive gland of H. aspersa. Overall, our work

  16. Pollution Characteristics and Sources of Polycyclic Aromatic Hydrocarbons in Riparian Soils Along Urban Rivers of Wenzhou City%温州城市河流河岸带土壤中PAHs的污染特征与来源

    Institute of Scientific and Technical Information of China (English)

    周婕成; 毕春娟; 陈振楼; 王璐; 许世远; 潘琪

    2012-01-01

    为研究城市河流河岸带土壤中多环芳烃(PAHs)的污染特征,于2010年8月沿温州九山外河和山下河河岸带采集了21个表层土壤样品,利用加速溶剂萃取仪(ASE)萃取,净化柱提取净化,使用气相色谱-质谱联用仪(GC-MS)分析了土壤中18种PAHs的含量.结果表明,温州九山外河和山下河河岸带表层土壤中PAHs含量范围为60.7~3 871.3 ng·g-1,山下河河岸带土壤中ΣPAHs含量显著低于九山外河.两条河流河岸带土壤中的PAHs均以2、3环的低环为主,平均占到PAHs总量的62.47%~72.51%.与国内外其他研究地区土壤中PAHs含量相比,研究河段河岸带土壤中的PAHs处于中等污染水平,但有3个样品中BaP浓度远大于前苏联土壤标准,应引起足够重视.利用Ant/(Ant+Phe)和Fla/(Fla+Pyr)比值法和主成分分析方法进行判源,温州城市河流河岸带土壤中的PAHs均表现出明显的燃烧源和石油源的综合来源特征。%Twenty one riparian soil samples along Jiushanwai River and Shanxia River of Wenzhou city were collected in August 2010 to investigate the pollution characteristics of polycyclic aromatic hydrocarbons(PAHs).The samples were extracted by an accelerated solvent extractor(ASE),purified by a purification column and determined by GC-MS.Results showed that the total concentrations of PAHs in the riparian soils ranged from 60.7 ng·g-1 to 3 871.3 ng·g-1,and the concentrations of PAHs in soils along the Shanxia River were significantly lower than the levels along Jiushanwai River.The dominant compounds were 2 to 3 rings in the riparian soils along both rivers,which in average accounted for 62.47%-72.51% in PAHs.Compared with the PAHs concentrations in soils of other areas in the world,the riparian soils of the studied rivers were moderately polluted by PAHs,but the concentrations of BaP in three soil samples were much higher than the soil standard value of the former Soviet Union

  17. High School Exit Exams and Hispanics

    Science.gov (United States)

    Adam, Michelle

    2005-01-01

    This article deals with the report, entitled "State High School Exit Exams: A Maturing Reform", that addressed the achievement gaps that exist for minority and English language learner (ELL) populations. In this article, the author shows how Hispanics and ELLs lag behind Caucasians in terms of passing percentage in different subject areas. The…

  18. Chaperone binding at the ribosomal exit tunnel

    DEFF Research Database (Denmark)

    Kristensen, Ole; Gajhede, Michael

    2003-01-01

    The exit tunnel region of the ribosome is well established as a focal point for interaction between the components that guide the fate of nascent polypeptides. One of these, the chaperone trigger factor (TF), associates with the 50S ribosomal subunit through its N-terminal domain. Targeting of TF...

  19. Determinants of Business Exits in Australia

    Directory of Open Access Journals (Sweden)

    Yongqiang Li

    2014-09-01

    Full Text Available The annually increasing firm exits have significant financial, legal and social impacts on productivity, employment and economic growth in Australia. However, evidence of the impacts of firm exits is sparse. This paper undertakes a first-ever study that empirically investigates the determinants and their impacts on firm churn. This paper is innovative to the literature in four aspects: (1 Local Region Areas (LGAs data, rarely available in other countries, has been used for the analysis; (2 using LGAs as the basic analytical unit is able to eliminate the heterogeneity problems encountered by other studies which are based on national and cross-national data; (3 panel data modelling techniques identify robust evidence; (4 systematic statistical tests guarantees the robustness of the results. The dataset, provided by Australia Bureau of Statistics, include 3462 observations of 577 Local Government Areas (LGAs during 2004-2009. The research identifies variables positively and negatively affecting the exits and finds that size matters in determining business exits. The last section concludes with a discussion of limitations and future research directions.

  20. Epigenetics as a First Exit Problem

    Science.gov (United States)

    Aurell, E.; Sneppen, K.

    2002-01-01

    We develop a framework to discuss the stability of epigenetic states as first exit problems in dynamical systems with noise. We consider in particular the stability of the lysogenic state of the λ prophage. The formalism defines a quantitative measure of robustness of inherited states.

  1. Effect of exit locations on ants escaping a two-exit room stressed with repellent

    Science.gov (United States)

    Wang, Shujie; Cao, Shuchao; Wang, Qiao; Lian, Liping; Song, Weiguo

    2016-09-01

    In order to investigate the effect of the distance between two exits on ant evacuation efficiency and the behavior of ants escaping from a two-exit room, we conducted ant egress experiments using Camponotus japonicus in multiple situations. We found that the ants demonstrated the phenomenon of "symmetry breaking" in this stress situation. It was also shown that different locations for the exits obviously affected the ants' egress efficiency by measuring the time intervals between individual egress and flow rate in eight repeated experiments, each of which contained five different distance between the two exits. In addition, it is demonstrated that there are differences between the predictions of Social Force Model of pedestrians and the behaviors of ants in stress conditions through comparing some important behavioral features, including position, trajectory, velocity, and density map.

  2. Mathematical design of a highway exit curve

    Science.gov (United States)

    Pakdemirli, Mehmet

    2016-01-01

    A highway exit curve is designed under the assumption that the tangential and normal components of the acceleration of the vehicle remain constant throughout the path. Using fundamental principles of physics and calculus, the differential equation determining the curve function is derived. The equation and initial conditions are cast into a dimensionless form first for universality of the results. It is found that the curves are effected by only one dimensionless parameter which is the ratio of the tangential acceleration to the normal acceleration. For no tangential acceleration, the equation can be solved analytically yielding a circular arc solution as expected. For nonzero tangential acceleration, the function is complicated and no closed-form solutions exist for the differential equation. The equation is solved numerically for various acceleration ratios. Discussions for applications to highway exits are given.

  3. When and how to exit quantitative easing?

    OpenAIRE

    Wen, Yi

    2014-01-01

    The essence of quantitative easing (QE) is reducing the cost of private borrowing through large-scale purchases of privately issued debt instead of public debt (Bernanke, 2009). Regardless of how effective this highly unconventional monetary policy may be in reviving private investment and the economy in general, it is time to consider how exiting from these private asset purchases will affect the economy. In a standard economic model, if monetary injections can increase aggregate output and ...

  4. Dynamic exit pupil trackers for autostereoscopic displays.

    Science.gov (United States)

    Akşit, Kaan; Baghsiahi, Hadi; Surman, Phil; Ölçer, Selim; Willman, Eero; Selviah, David R; Day, Sally; Urey, Hakan

    2013-06-17

    This paper describes the first demonstrations of two dynamic exit pupil (DEP) tracker techniques for autostereoscopic displays. The first DEP tracker forms an exit pupil pair for a single viewer in a defined space with low intraocular crosstalk using a pair of moving shutter glasses located within the optical system. A display prototype using the first DEP tracker is constructed from a pair of laser projectors, pupil-forming optics, moving shutter glasses at an intermediate pupil plane, an image relay lens, and a Gabor superlens based viewing screen. The left and right eye images are presented time-sequentially to a single viewer and seen as a 3D image without wearing glasses and allows the viewer to move within a region of 40 cm × 20 cm in the lateral plane, and 30 cm along the axial axis. The second DEP optics can move the exit pupil location dynamically in a much larger 3D space by using a custom spatial light modulator (SLM) forming an array of shutters. Simultaneous control of multiple exit pupils in both lateral and axial axes is demonstrated for the first time and provides a viewing volume with an axial extent of 0.6-3 m from the screen and within a lateral viewing angle of ± 20° for multiple viewers. This system has acceptable crosstalk (< 5%) between the stereo image pairs. In this novel version of the display the optical system is used as an advanced dynamic backlight for a liquid crystal display (LCD). This has advantages in terms of overall display size as there is no requirement for an intermediate image, and in image quality. This system has acceptable crosstalk (< 5%) between the stereo image pairs. PMID:23787621

  5. Exits from unemployment : recall or new job

    OpenAIRE

    Muñoz-Bullón, Fernando; Alba, Alfonso; Arranz, José M.

    2006-01-01

    JEL Classification Numbers J21, J24 This paper studies transitions out of unemployment in Spain distinguishing between recall to the same employer and reemployment in a new job. We use a large sample of newly unemployed workers obtained from Social Security records for Spain. These data contain information about each individual's employer identy before and after the unemployment spell. A discrete-time duration model with competing risks of exits serves us to investigate the factors that in...

  6. Dynamic exit pupil trackers for autostereoscopic displays

    OpenAIRE

    Akşit, Kaan; Ölçer, Selim; Ürey, Hakan; Baghsiahi, Hadi; Surman, Phil; Willman, Eero; Selviah, David R.; Day, Sally

    2013-01-01

    Dynamic exit pupil trackers for autostereoscopic displays Kaan Akşit,1,* Hadi Baghsiahi,2 Phil Surman,3 Selim Ӧlçer,1 Eero Willman,2 David R. Selviah,2 Sally Day, 2 and Hakan Urey1 1Koç University, Department of Electrical Engineering Istanbul, 34450, Turkey 2University College London, UCL, Department of Electronic & Electrical Engineering, WC1E 7JE, London, UK 3De Montfort University, Department of Computer Technology, Leicester, UK * Abstract: This...

  7. Entry and Exit in a Liberalised Market

    OpenAIRE

    Maria José Gil-Moltó; Claudio A. Piga

    2007-01-01

    We analyse the entry and exit activity in the UK airline markets in the post-liberalisation period and study the differential traits between traditional and low cost carriers. Alongside with the characteristics traditionally highlighted as determinants of entry (e.g., airport presence and network economies), we find that the existence of charter or seasonal operators, product differentiation opportunities and the level of quality provided by the incumbents are also relevant in explaining entr...

  8. Exit exams and high school dropout

    OpenAIRE

    Dave E. Marcotte

    2011-01-01

    In this paper, I consider the impact of the expansion of exams students must pass in order to graduate high school on dropout rates. "Exit exams," as these tests are known, have become more common, and more difficult. These exams are controversial, with opponents claiming they drive marginal students out of school, and proponents arguing they align student interests with those of the school and encourage teachers and administrators to provide effort and resources on the students' behalf. I ma...

  9. The Exit Rates of Liquidated Venture Capital Funds

    OpenAIRE

    Markus Laine; Sami Torstila

    2005-01-01

    Exit rates provide a simple yet practical measure for evaluating and benchmarking the performance of venture capital funds. We create a sample of 138 liquidated U.S. venture capital funds and investigate the outcomes of their 4,549 portfolio companies. We study exit rates, proportions of different exit routes, and their determinants. The median fund in our sample exited 19% of portfolio companies through an IPO, 7% through a sale of listed equity, and 23% through mergers or acquisitions. Ther...

  10. Profile of State High School Exit Exam Policies. New Jersey

    Science.gov (United States)

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on New Jersey's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  11. Profile of State High School Exit Exam Policies. Ohio

    Science.gov (United States)

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Ohio's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  12. Profile of State High School Exit Exam Policies. Oklahoma

    Science.gov (United States)

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on Oklahoma's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  13. Profile of State High School Exit Exam Policies. New York

    Science.gov (United States)

    Center on Education Policy, 2011

    2011-01-01

    This individual profile provides information on New York's high school exit exam standards and policies. Some of the categories presented include: (1) State exit exam policy; (2) Type of Test; (3) Purpose; (4) Major changes in exit exam policy since the 2009-10 school year for financial reasons; (5) Subjects tested on exam; (6) Grade exam first…

  14. A Legal Overview and History of High School Exit Exams

    Science.gov (United States)

    Sutton, Lenford

    2006-01-01

    State exit exams, also known as graduation tests, are tests that student must pass to graduate from high school. These tests are more influential than ever. Accordingly, in 2004, 20 states required students to pass an exit exam to graduate from high school, and six additional states will implement an exit exam by 2009. This affects more than half…

  15. 14 CFR 25.813 - Emergency exit access.

    Science.gov (United States)

    2010-01-01

    ... landing and any passenger emergency exit, such that the door crosses any egress path (including aisles... (except those seats on the flightdeck), occupiable for takeoff and landing, from any emergency exit, the... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Emergency exit access. 25.813 Section...

  16. 14 CFR 27.805 - Flight crew emergency exits.

    Science.gov (United States)

    2010-01-01

    ... emergency landing on water. This must be shown by test, demonstration, or analysis. ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flight crew emergency exits. 27.805 Section... § 27.805 Flight crew emergency exits. (a) For rotorcraft with passenger emergency exits that are...

  17. Exit Exams: Decreases or Increases the Dropout Rate

    Science.gov (United States)

    Barnes, Teresa A.

    2009-01-01

    The purpose of this paper was to examine the impact of exit exams on the dropout rate. Data was gathered from several research articles. The most impressionable research revealed exit exams have a negative effect on minorities, especially black males. Results indicate by 2012, that exit exams in 25 states will affect 81 percent of minority high…

  18. The exit distribution for iterated Brownian motion in cones

    OpenAIRE

    Banuelos, Rodrigo; DeBlassie, Dante

    2004-01-01

    We study the distribution of the exit place of iterated Brownian motion in a cone, obtaining information about the chance of the exit place having large magnitude. Along the way, we determine the joint distribution of the exit time and exit place of Brownian motion in a cone. This yields information on large values of the exit place (harmonic measure) for Brownian motion. The harmonic measure for cones has been studied by many authors for many years. Our results are sharper than any previousl...

  19. Exit time distribution in spherically symmetric two-dimensional domains

    CERN Document Server

    Rupprecht, J -F; Grebenkov, D S; Voituriez, R

    2014-01-01

    The distribution of exit times is computed for a Brownian particle in spherically symmetric two- dimensional domains (disks, angular sectors, annuli) and in rectangles that contain an exit on their boundary. The governing partial differential equation of Helmholtz type with mixed Dirichlet- Neumann boundary conditions is solved analytically. We propose both an exact solution relying on a matrix inversion, and an approximate explicit solution. The approximate solution is shown to be exact for an exit of vanishing size and to be accurate even for large exits. For angular sectors, we also derive exact explicit formulas for the moments of the exit time. For annuli and rectangles, the approximate expression of the mean exit time is shown to be very accurate even for large exits. The analysis is also extended to biased diffusion. Since the Helmholtz equation with mixed boundary conditions is encountered in microfluidics, heat propagation, quantum billiards, and acoustics, the developed method can find numerous appl...

  20. Superconductivity in aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Highlights: • Aromatic superconductor is one of core research subjects in superconductivity. Superconductivity is observed in certain metal-doped aromatic hydrocarbons. Some serious problems to be solved exist for future advancement of the research. This article shows the present status of aromatic superconductors. - Abstract: ‘Aromatic hydrocarbon’ implies an organic molecule that satisfies the (4n + 2) π-electron rule and consists of benzene rings. Doping solid aromatic hydrocarbons with metals provides the superconductivity. The first discovery of such superconductivity was made for K-doped picene (Kxpicene, five benzene rings). Its superconducting transition temperatures (Tc’s) were 7 and 18 K. Recently, we found a new superconducting Kxpicene phase with a Tc as high as 14 K, so we now know that Kxpicene possesses multiple superconducting phases. Besides Kxpicene, we discovered new superconductors such as Rbxpicene and Caxpicene. A most serious problem is that the shielding fraction is ⩽15% for Kxpicene and Rbxpicene, and it is often ∼1% for other superconductors. Such low shielding fractions have made it difficult to determine the crystal structures of superconducting phases. Nevertheless, many research groups have expended a great deal of effort to make high quality hydrocarbon superconductors in the five years since the discovery of hydrocarbon superconductivity. At the present stage, superconductivity is observed in certain metal-doped aromatic hydrocarbons (picene, phenanthrene and dibenzopentacene), but the shielding fraction remains stubbornly low. The highest priority research area is to prepare aromatic superconductors with a high superconducting volume-fraction. Despite these difficulties, aromatic superconductivity is still a core research target and presents interesting and potentially breakthrough challenges, such as the positive pressure dependence of Tc that is clearly observed in some phases of aromatic hydrocarbon superconductors

  1. BST2/Tetherin Inhibition of Alphavirus Exit

    Directory of Open Access Journals (Sweden)

    Yaw Shin Ooi

    2015-04-01

    Full Text Available Alphaviruses such as chikungunya virus (CHIKV and Semliki Forest virus (SFV are small enveloped RNA viruses that bud from the plasma membrane. Tetherin/BST2 is an interferon-induced host membrane protein that inhibits the release of many enveloped viruses via direct tethering of budded particles to the cell surface. Alphaviruses have highly organized structures and exclude host membrane proteins from the site of budding, suggesting that their release might be insensitive to tetherin inhibition. Here, we demonstrated that exogenously-expressed tetherin efficiently inhibited the release of SFV and CHIKV particles from host cells without affecting virus entry and infection. Alphavirus release was also inhibited by the endogenous levels of tetherin in HeLa cells. While rubella virus (RuV and dengue virus (DENV have structural similarities to alphaviruses, tetherin inhibited the release of RuV but not DENV. We found that two recently identified tetherin isoforms differing in length at the N-terminus exhibited distinct capabilities in restricting alphavirus release. SFV exit was efficiently inhibited by the long isoform but not the short isoform of tetherin, while both isoforms inhibited vesicular stomatitis virus exit. Thus, in spite of the organized structure of the virus particle, tetherin specifically blocks alphavirus release and shows an interesting isoform requirement.

  2. Aromatic VOCs global influence in the ozone production

    Science.gov (United States)

    Cabrera-Perez, David; Pozzer, Andrea

    2016-04-01

    Aromatic hydrocarbons are a subgroup of Volatile Organic Compounds (VOCs) of special interest in the atmosphere of urban and semi-urban areas. Aromatics form a high fraction of VOCs, are highly reactive and upon oxidation they are an important source of ozone. These group of VOCs are released to the atmosphere by processes related to biomass burning and fossil fuel consumption, while they are removed from the atmosphere primarily by OH reaction and by dry deposition. In addition, a branch of aromatics (ortho-nitrophenols) produce HONO upon photolysis, which is responsible of certain amount of the OH recycling. Despite their importance in the atmosphere in anthropogenic polluted areas, the influence of aromatics in the ozone production remains largely unknown. This is of particular relevance, being ozone a pollutant with severe side effects on air quality, health and climate. In this work the atmospheric impacts at global scale of the most emitted aromatic VOCs in the gas phase (benzene, toluene, xylenes, ethylbenzene, styrene, phenol, benzaldehyde and trimethylbenzenes) are analysed and assessed. Specifically, the impact on ozone due to aromatic oxidation is estimated, as this is of great interest in large urban areas and can be helpful for developing air pollution control strategies. Further targets are the quantification of the NOx loss and the OH recycling due to aromatic oxidation. In order to investigate these processes, two simulations were performed with the numerical chemistry and climate simulation ECHAM/MESSy Atmospheric Chemistry (EMAC) model. The simulations compare two cases, one with ozone concentrations when aromatics are present or the second one when they are missing. Finally, model simulated ozone is compared against a global set of observations in order to better constrain the model accuracy.

  3. Particle Pollution

    Science.gov (United States)

    ... Your Health Particle Pollution Public Health Issues Particle Pollution Recommend on Facebook Tweet Share Compartir Particle pollution ... see them in the air. Where does particle pollution come from? Particle pollution can come from two ...

  4. Fatal exit the automotive black box debate

    CERN Document Server

    Kowalick, Tom

    2005-01-01

    "Fatal Exit: The Automotive Black Box Debate cuts through thirty years of political wrangling and institutional biases to provide an argument for the Motor Vehicle Event Data Recorder (MVEDR). This automotive equivalent of an airplane's flight recorder or black box is intended to solve the mysteries of car crashes and improve the safety of our roads. The reader is taken inside the automotive industry and the government highway safety establishment to foster an understanding of the politics and the positions on all sides of this safety debate. The author takes an unbiased approach, chronologically presenting each argument and uncovering the agendas and mandates of each of the stakeholders." "This publication is essential reading for all consumers who need to have their voices heard on this critical issue, as well as for attorneys, public safety advocates, public policy administrators, engineers, automotive professionals, journalists, and insurance executives."--Jacket.

  5. Proton microprobe with windowless-exit port

    International Nuclear Information System (INIS)

    Construction and use of a windowless-exit port with a proton microprobe apparatus is described. The use of a differential-pumping system permits bombardment of samples at atmospheric pressure without the problems caused by passing the beam through thin foils. Methods used for fabrication of beam collimators and for measurement of the beam diameter are discussed. The sensitivity for trace element determination by observation of K X-rays is given. Sample spectra obtained are presented and contrasted with results obtained with a scanning electron microscope with energy-dispersive X-ray detection. The localization of Zn in a rat incisor is given to demonstrate the type of data uniquely obtainable with the proton microprobe. (Auth.)

  6. DNB exit scraper—Concept and engineering

    Energy Technology Data Exchange (ETDEWEB)

    Gangadharan Nair, R., E-mail: roopeshgnair@gmail.com [ITER-India, Institute for Plasma Research, A-29, Sector 25, GIDC, Gandhinagar, Gujarat 380025 (India); Bandyopadhyay, M.; Rotti, C. [ITER-India, Institute for Plasma Research, A-29, Sector 25, GIDC, Gandhinagar, Gujarat 380025 (India); Ghate, M. [ITER-India, Institute for Plasma Research, A-29, Sector 25, GIDC, Gandhinagar, Gujarat 380025 (India); Institute for Plasma Research, Gandhinagar, Gujarat 382428 (India); Acharya, K.; Chakraborty, A.K. [ITER-India, Institute for Plasma Research, A-29, Sector 25, GIDC, Gandhinagar, Gujarat 380025 (India); Schunke, B.; Chareyre, J.; Graceffa, J.; Hemsworth, R. [ITER Organization, Route de Vinon, 13115 Saint Paul Lez Durance (France)

    2013-10-15

    The 100 kV negative hydrogen ion source based Diagnostic Neutral Beam (DNB) injector is part of the Indian procurement for ITER. The DNB is designed to deliver an 18–20 A hydrogen neutral beam to the ITER plasma. The exit scraper (ES) defines the profile of the beam after it leaves the calorimeter, the last Beam Line Components (BLCs) during operation. BTR and PDP codes are used to obtain the optimum entry and exit opening dimensions of the ES, so as to deliver the maximum power to the tokamak plasma, and to limit the power to downstream components due to beam interception, to protect front end components from the interception of re-ionized devious particles. Each horizontal heat transfer (HT) panel of ES receives a total power of 85 kW for each symmetric 10 mrad beam (worst case scenario) with peak power density of 1.17 MW/m{sup 2}. The thermo hydraulic design is carried out to withstand the heat flux due to the beam interception on the ES. The mechanical design of the ES is carried out by considering the spatial constraints in the DNB system and the remote handling (RH) system. In the present design, the copper heat transfer panels are directly bolted to the structural member. Protection shall be incorporated to ensure that there is no exposure of the bolt head. The thermo-mechanical analysis has been carried out for the normal, off-normal (accidental/worst-case) events of the ITER DNB. During normal operation, the maximum possible von Mises stress of the order of 62.4 MPa can be expected on the bottom heat transfer panel, and the corresponding deflection of the structure is of the order of 0.62 mm. All the stress checks were carried out with respect to the Structural Design Criteria for In-vessel Components (SDC-IC) criterion. The paper shall present the ES design highlighting its salient features.

  7. DNB exit scraper—Concept and engineering

    International Nuclear Information System (INIS)

    The 100 kV negative hydrogen ion source based Diagnostic Neutral Beam (DNB) injector is part of the Indian procurement for ITER. The DNB is designed to deliver an 18–20 A hydrogen neutral beam to the ITER plasma. The exit scraper (ES) defines the profile of the beam after it leaves the calorimeter, the last Beam Line Components (BLCs) during operation. BTR and PDP codes are used to obtain the optimum entry and exit opening dimensions of the ES, so as to deliver the maximum power to the tokamak plasma, and to limit the power to downstream components due to beam interception, to protect front end components from the interception of re-ionized devious particles. Each horizontal heat transfer (HT) panel of ES receives a total power of 85 kW for each symmetric 10 mrad beam (worst case scenario) with peak power density of 1.17 MW/m2. The thermo hydraulic design is carried out to withstand the heat flux due to the beam interception on the ES. The mechanical design of the ES is carried out by considering the spatial constraints in the DNB system and the remote handling (RH) system. In the present design, the copper heat transfer panels are directly bolted to the structural member. Protection shall be incorporated to ensure that there is no exposure of the bolt head. The thermo-mechanical analysis has been carried out for the normal, off-normal (accidental/worst-case) events of the ITER DNB. During normal operation, the maximum possible von Mises stress of the order of 62.4 MPa can be expected on the bottom heat transfer panel, and the corresponding deflection of the structure is of the order of 0.62 mm. All the stress checks were carried out with respect to the Structural Design Criteria for In-vessel Components (SDC-IC) criterion. The paper shall present the ES design highlighting its salient features

  8. Exit processes of micro-businesses: The decision to transfer

    OpenAIRE

    Leroy, Hannes; Manigart, Sophie; Meuleman, Miguel

    2007-01-01

    Ultimately all entrepreneurs are confronted with the exit of their business. When considering the large amount and increasing age of micro-business owners, this topic warrants more investigation than it has received so far. Our research sheds more light on the entrepreneurial exit process for micro-businesses. Starting from the theory of planned behavior (TPB), our study models the business exit as a dual-stage process of intentions prediction action. After testing the applicability of the TP...

  9. The story's end : a narrative analysis of entrepreneurial exit

    OpenAIRE

    Gill, Jameson

    2015-01-01

    Based on a period of participant observation I examine the exit of the Managing Director from a family owned business. The study reflects on theories of entrepreneurial exit at both the level of the individual and the organisation. Through the adoption of a two step empirical analysis based on narrative theory, conclusions are drawn regarding the events and the Managing Director’s actions which were antecedent to his announcement of exit. The article contributes insights regarding how an indi...

  10. Superconductivity in aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Kubozono, Yoshihiro, E-mail: kubozono@cc.okayama-u.ac.jp [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Research Center of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530 (Japan); Japan Science and Technology Agency, ACT-C, Kawaguchi 332-0012 (Japan); Goto, Hidenori; Jabuchi, Taihei [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Yokoya, Takayoshi [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Research Center of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530 (Japan); Kambe, Takashi [Department of Physics, Okayama University, Okayama 700-8530 (Japan); Sakai, Yusuke; Izumi, Masanari; Zheng, Lu; Hamao, Shino; Nguyen, Huyen L.T. [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Sakata, Masafumi; Kagayama, Tomoko; Shimizu, Katsuya [Center of Science and Technology under Extreme Conditions, Osaka University, Osaka 560-8531 (Japan)

    2015-07-15

    Highlights: • Aromatic superconductor is one of core research subjects in superconductivity. Superconductivity is observed in certain metal-doped aromatic hydrocarbons. Some serious problems to be solved exist for future advancement of the research. This article shows the present status of aromatic superconductors. - Abstract: ‘Aromatic hydrocarbon’ implies an organic molecule that satisfies the (4n + 2) π-electron rule and consists of benzene rings. Doping solid aromatic hydrocarbons with metals provides the superconductivity. The first discovery of such superconductivity was made for K-doped picene (K{sub x}picene, five benzene rings). Its superconducting transition temperatures (T{sub c}’s) were 7 and 18 K. Recently, we found a new superconducting K{sub x}picene phase with a T{sub c} as high as 14 K, so we now know that K{sub x}picene possesses multiple superconducting phases. Besides K{sub x}picene, we discovered new superconductors such as Rb{sub x}picene and Ca{sub x}picene. A most serious problem is that the shielding fraction is ⩽15% for K{sub x}picene and Rb{sub x}picene, and it is often ∼1% for other superconductors. Such low shielding fractions have made it difficult to determine the crystal structures of superconducting phases. Nevertheless, many research groups have expended a great deal of effort to make high quality hydrocarbon superconductors in the five years since the discovery of hydrocarbon superconductivity. At the present stage, superconductivity is observed in certain metal-doped aromatic hydrocarbons (picene, phenanthrene and dibenzopentacene), but the shielding fraction remains stubbornly low. The highest priority research area is to prepare aromatic superconductors with a high superconducting volume-fraction. Despite these difficulties, aromatic superconductivity is still a core research target and presents interesting and potentially breakthrough challenges, such as the positive pressure dependence of T{sub c} that is clearly

  11. Computer Simulations Reveal Multiple Functions for Aromatic Residues in Cellulase Enzymes (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-07-01

    NREL researchers use high-performance computing to demonstrate fundamental roles of aromatic residues in cellulase enzyme tunnels. National Renewable Energy Laboratory (NREL) computer simulations of a key industrial enzyme, the Trichoderma reesei Family 6 cellulase (Cel6A), predict that aromatic residues near the enzyme's active site and at the entrance and exit tunnel perform different functions in substrate binding and catalysis, depending on their location in the enzyme. These results suggest that nature employs aromatic-carbohydrate interactions with a wide variety of binding affinities for diverse functions. Outcomes also suggest that protein engineering strategies in which mutations are made around the binding sites may require tailoring specific to the enzyme family. Cellulase enzymes ubiquitously exhibit tunnels or clefts lined with aromatic residues for processing carbohydrate polymers to monomers, but the molecular-level role of these aromatic residues remains unknown. In silico mutation of the aromatic residues near the catalytic site of Cel6A has little impact on the binding affinity, but simulation suggests that these residues play a major role in the glucopyranose ring distortion necessary for cleaving glycosidic bonds to produce fermentable sugars. Removal of aromatic residues at the entrance and exit of the cellulase tunnel, however, dramatically impacts the binding affinity. This suggests that these residues play a role in acquiring cellulose chains from the cellulose crystal and stabilizing the reaction product, respectively. These results illustrate that the role of aromatic-carbohydrate interactions varies dramatically depending on the position in the enzyme tunnel. As aromatic-carbohydrate interactions are present in all carbohydrate-active enzymes, the results have implications for understanding protein structure-function relationships in carbohydrate metabolism and recognition, carbon turnover in nature, and protein engineering

  12. Bioavailability of Polycyclic Aromatic Hydrocarbons in Soils and Sediments

    NARCIS (Netherlands)

    Cuypers, M.P.

    2001-01-01

    Polycyclic aromatic hydrocarbons (PAHs) constitute a group of priority pollutants which are of increasing environmental concern because of their adverse effects on humans, animals, and plants. Soils and sediments generally serve as a sink for PAHs, which leads to the accumulation of PAHs at contamin

  13. AGRONOMIC OPTIMIZATION FOR PHYTOREMEDIATION OF POLYCYCLIC AROMATIC HYDROCARBONS

    Science.gov (United States)

    Phytoremediation is a low-cost method of using plants to degrade, volatilize or sequester organic and metal pollutants that has been used in efforts to remediate sites contaminated with polycyclic aromatic hydrocarbon (PAH) refinery wastes. Non-native plant species aggressivel...

  14. Assessing Undergraduate Curriculum Through Student Exit Vectors

    Science.gov (United States)

    Keane, C. M.; Gonzales, L.; Martinez, C.

    2008-12-01

    One aspect of assessing the undergraduate curriculum is recognizing that the exit vector of the student is a metric in the absence of a structured assessment program. Detailed knowledge across all geosciences departments regarding the disposition of their recent baccalaureate recipients has been at best inconsistent, and in the case of about half of geoscience programs, non-existent. However, through examining of multiple datasets, a pattern of disposition of geosciences BS recipients emerges, providing a snapshot of the system- wide response to the system-wide "average" program. This pattern can also be juxtaposed against several frameworks of desired skill sets for recent graduates and the employment sectors likely to hire them. The question remains is can one deduce the effectiveness of the undergraduate program in placing graduates in their next step, whether in graduate school or the workplace. Likewise, with an increasing scrutiny on the "value" of an education, is the resulting economic gain sufficient for the student, such that programs will be viewed as sustainable. A factor in answering this question is the importance of the undergraduate program in the ultimate destination of the professional. Clear pathways exist for "optimal" schools for the production of new faculty and new industry professionals, but is it possible to identify those trends further up the educational pipeline? One major mechanism to examine the undergraduate program effectiveness related to exit vectors is to look at hiring trends witnessed related to markedly different program structures, such as those at universities outside of the United States. Rectifying academic programs between the United States and other national systems is often a challenge, but even given the substantial differences between depth of technical knowledge and breadth of education across these programs, in the end, the sum product is often viewed as roughly comparable. This paper will look at end

  15. Spatial variability in persistent organic pollutants and polycyclic aromatic hydrocarbons found in beach-stranded pellets along the coast of the state of São Paulo, southeastern Brazil.

    Science.gov (United States)

    Taniguchi, Satie; Colabuono, Fernanda I; Dias, Patrick S; Oliveira, Renato; Fisner, Mara; Turra, Alexander; Izar, Gabriel M; Abessa, Denis M S; Saha, Mahua; Hosoda, Junki; Yamashita, Rei; Takada, Hideshige; Lourenço, Rafael A; Magalhães, Caio A; Bícego, Márcia C; Montone, Rosalinda C

    2016-05-15

    High spatial variability in polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides, such as DDTs, and polybrominated diphenylethers was observed in plastic pellets collected randomly from 41 beaches (15 cities) in 2010 from the coast of state of São Paulo, southeastern Brazil. The highest concentrations ranged, in ng g(-1), from 192 to 13,708, 3.41 to 7554 and coastline, which is affected by both waste disposal and large port and industrial complex. Additional samples were collected in this central area and PCB concentrations, in ngg(-)(1), were much higher in 2012 (1569 to 10,504) than in 2009/2010 (173 to 309) and 2014 (411), which is likely related to leakages of the PCB commercial mixture. PMID:27021625

  16. Towards an Orderly Exit Regime in English Higher Education

    Science.gov (United States)

    Fisher, Andrew

    2016-01-01

    In a competitive market, the exit of those suppliers who cannot offer an attractive product at an attractive price is seen as desirable. However, the consequences for consumers when their own supplier leaves the market in an unplanned or disorderly way may be undesirable. Exit regimes exist in regulated markets to ensure that consumers are not…

  17. Exit Examinations, Peer Academic Climate, and Adolescents' Developmental Outcomes

    Science.gov (United States)

    Benner, Aprile D.

    2013-01-01

    Implications of high school exit examination performance were examined with a sample of 672 racial/ethnic minority students. Exit examination failure in the 10th grade was negatively linked to subsequent grade point average, school engagement, and school belonging one year later, controlling for outcomes prior to taking the examination.…

  18. Exit and voice in dutch social health insurance.

    NARCIS (Netherlands)

    Gress, S.; Delnoij, D.; Groenewegen, P.P.

    2003-01-01

    According to Hirschmann's concept of exit and voice, people have two options to make sure that firms or organisations realise what they (their consumers or members) are interested in (Hirschmann 1970). In the Dutch public health insurance system voice existed for a long time, but exit was only intro

  19. Exit Surveying of Interns: Demonstrating Impact on Young Professionals

    Science.gov (United States)

    Muscio, Cara

    2011-01-01

    Documenting impact is becoming increasingly important as funding becomes tighter for Extension programs. An exit survey for interns conducted via an online survey tool is an opportunity to collect information on knowledge and skill gains, as well as document changes in intentions and attitudes about future career paths. An exit survey conducted…

  20. State High School Tests: Exit Exams and Other Assessments

    Science.gov (United States)

    Dietz, Shelby

    2010-01-01

    Since 2002, the Center on Education Policy (CEP), an independent nonprofit organization, has been studying state high school exit examinations--tests students must pass to receive a high school diploma. This is CEP's ninth annual report on exit exams. The information in this report comes from several sources: CEP's survey of states that have…

  1. Exit and Voice: Organizational Loyalty and Dispute Resolution Strategies

    Science.gov (United States)

    Hoffmann, Elizabeth A.

    2006-01-01

    This study compares workplace dispute resolution strategies (exit, voice and toleration) in matched pairs of conventional and worker-owned cooperative organizations operating in three industries--coal mining, taxicab driving and organic food distribution. Building on Hirschman's classic exit, voice and loyalty thesis, this research demonstrates…

  2. Near field and exit wave computations for electron microscopy

    International Nuclear Information System (INIS)

    The partial wave phase shift formalism of atomic scattering is applied to compute exit wave functions for isolated Au and Si atoms under both plane wave and focused probe illumination. Connections between the far field and near field (exit) waves are clarified. This approach treats the Coulomb singularity properly though at 100 keV large numbers of phase shifts are required. In principle any form of incident wave can be handled so it may provide a means for testing traditional scattering theories used in electron microscopy. By applying the analysis to an atom embedded in a constant potential rather than free space, exit spheres of radius half the interatomic spacing can be used. - Highlights: • Critique of current theories of electron scattering in EM. • Near field and far field relationship. • Phase shift scattering theory adapted for exit wave computation. • Exit wave computations for an Au atom with plane and focused wave illumination

  3. Is the publication of exit poll results morally permissible?

    DEFF Research Database (Denmark)

    Sønderholm, Jørn

    2016-01-01

    This article is about exit polls. It addresses the question of whether or not it is morally permissible to publish exit poll results. The conclusion of the article is that an affirmative answer should be given to this question. In section 2, the master argument in favor of the moral permissibility...... of the publication of exit poll results is introduced. This is a strong argument. It is, however, argued that it might be the case that the conclusion of this argument should be rejected if there are other, and weightier, arguments against the idea that the publication of exit poll results is morally...... permissible. In section 3, the strongest arguments against the moral permissibility of the publication of exit poll results are outlined and discussed. The conclusion of this section is that all these arguments fail in their intended purpose. The conclusion of the article is therefore justified....

  4. Suicide, Canadian law, and Exit International's "peaceful pill".

    Science.gov (United States)

    Ogden, Russel D

    2010-11-01

    Australia's Exit International ("Exit") is probably the most visible and controversial right-to-die organization in the world. Founded by Dr. Philip Nitschke, Exit is known for do-it-yourself ("DIY") suicide workshops and a book banned in Australia: The Peaceful Pill Handbook. In 2009, Exit held its first workshop in Canada. Due to legal concerns, the Vancouver Public Library reneged on a commitment to give Exit a venue, so the workshop proceeded in the sanctuary of a church hall. This article summarizes the history of suicide law in Canada and gives an overview of the emerging DIY movement. A case report describes how a Canadian woman studied Exit's literature and learned how to import veterinary pentobarbital. In accordance with Exit's information, she ended her life. Ethical and legal implications for researching DIY suicide are discussed and it is argued that prohibition contributes to an undesirable situation of uncontrolled and unregulated suicide. Whether they are prohibited, permitted, or tolerated, suicide and assisted suicide are controversial. Their legal treatment in Canada is conflicting because suicide is not a crime but it is a serious offense to assist, encourage, or counsel someone to suicide. Individuals can lawfully take their lives, but they must act independently. This legal situation has given rise to a do-it-yourself ("DIY") right-to-die movement dedicated to technologies and information to enhance the possibilities for planned and humane suicide, while limiting the legal exposure of sympathetic third parties (Martin, 2010; Ogden 2001). My aim is to summarize the legal history of suicide in Canada and discuss the emerging social movement for DIY suicide and assistance in suicide. Exit International ("Exit"), based in Australia, is a leading organization in this movement. I present a case report that describes how a Canadian woman ended her life using DIY techniques learned from Exit. Some ethical and legal implications for researching DIY

  5. Biomarkers of genotoxicity of air pollution (the AULIS project): bulky DNA adducts in subjects with moderate to low exposures to airborne polycyclic aromatic hydrocarbons and their relationship to environmental tobycco smoke and other parameters

    Czech Academy of Sciences Publication Activity Database

    Georgiadis, P.; Topinka, Jan; Stoikidou, M.; Kaila, S.; Gioka, M.; Katsouyanni, K.; Šrám, Radim; Autrup, H.; Kyrtopoulos, S. A.

    2001-01-01

    Roč. 22, č. 9 (2001), s. 1447-1457. ISSN 0143-3334 R&D Projects: GA MŽP SI/340/2/00 Grant ostatní: EU(XC) ENV4V-CT96-0203; EU(XC) IC20CT960063 Institutional research plan: CEZ:AV0Z5039906 Keywords : biomarkers * air pollution Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 4.543, year: 2001

  6. Aromatic Hydrocarbons: Degrading Bacteria in the Desert Soil of Kuwait

    International Nuclear Information System (INIS)

    Soil samples of different levels of oil pollutants were collected from Kuwait's Burgan Oil Field, near an oil lake. The samples represented, highly polluted (8.0% w/w), moderately polluted (2.1%-3.4%) and slightly polluted (2.1%-3.4%) and slightly polluted (0.5- 0.8%). The aromatic fractions of the collected samples were in the range of (0.21-2.57g/100g) soil. (GC) analysis of the aromatic fractions of the resolution of the different individual (PAHs) revealed the presence of (16) different (PAHs) resolved from the aromatic fraction of the highly polluted sample (S3). (15), (14) and (13) individual (PAHs) were identified soil samples (S5), (S2) and (S1, S4, S6) respectively. The most frequent (PAH) was indeno (1, 2, 3-c, d) pyrene (22.5%-45.11%) followed chrysene (13.6%-19.48%). Eight carcinogenic (PAHs) were resolved from the aromatic fractions of the polluted samples. Total carcinogenic (PAHs) recorded in this study were in this study were in the range of (11.53) (forS4) - (510.98) (for S3) ppm. The counts of (CFU) of aromatic degraders (AD) were in the range of (3x10) - (110x 10) (CFU/g) soil (with a percent of (2.2%-69.6%)). The results show that, higher counts of (AD) were recorded from a highly polluted sample (S3), followed by the moderately polluted samples; total of (51) bacteria, that gave presumptive positive biodegradation activities, were isolated and identified (45.1%) of them were isolated and identified. (45.1%) of them were isolated from the highly polluted sample (S3). Total of (13) different species were identified of which Micrococcus luteus was more frequent (23.5) followed by Bacillus licheniformis (19.6%) and Bacillus subtilis (11.8%). The three Pseudomonas species collectively were presented by (11.8%). Five different species proved to be of good activities, they are: Bacillus brevis, Bacillus lichenoformis, Pseudomonas aeruginosa, Pseudomonas stutzeri and Pseudomonas flourescens. The ability of five species and their mixture was

  7. Computing the Exit Complexity of Knowledge in Distributed Quantum Computers

    Directory of Open Access Journals (Sweden)

    M.A.Abbas

    2013-01-01

    Full Text Available Distributed Quantum computers abide from the exit complexity of the knowledge. The exit complexity is the accrue of the nodal information needed to clarify the total egress system with deference to a distinguished exit node. The core objective of this paper is to compile an arrogant methodology for assessing the exit complexity of the knowledge in distributed quantum computers. The proposed methodology is based on contouring the knowledge using the unlabeled binary trees, hence building an benchmarked and a computer based model. The proposed methodology dramatizes knowledge autocratically calculates the exit complexity. The methodology consists of several amphitheaters, starting with detecting the baron aspect of the tree of others entitled express knowledge and then measure the volume of information and the complexity of behavior destining from the bargain of information. Then calculate egress resulting from episodes that do not lead to the withdrawal of the information. In the end is calculated total egress complexity and then appraised total exit complexity of the system. Given the complexity of the operations within the Distributed Computing Quantity, this research addresses effective transactions that could affect the three-dimensional behavior of knowledge. The results materialized that the best affair where total exit complexity as minimal as possible is a picture of a binary tree is entitled at the rate of positive and negative cardinal points medium value. It could be argued that these cardinal points should not amass the upper bound apex or minimum.

  8. Urban air pollution climates throughout the world

    DEFF Research Database (Denmark)

    Hertel, Ole; Goodsite, Michael Evan

    2009-01-01

    The extent of the urban area, the local emission density, and the temporal pattern in the releases govern the local contribution to air pollution levels in urban environments. However, meteorological conditions also heavily affect the actual pollution levels as they govern the dispersion conditions...... air pollution climates, particulate pollution in general together with gaseous and particulate polycyclic aromatic hydrocarbons (PAHs) and heavy metals are those where further field measurements, characterization and laboratory studies are urgently needed in order to fully assess the health impact on...... the urban population and provide the right basis for future urban air pollution management. © Royal Society of Chemistry 2009....

  9. Point Pollution Sources Dimensioning

    Directory of Open Access Journals (Sweden)

    Georgeta CUCULEANU

    2011-06-01

    Full Text Available In this paper a method for determining the main physical characteristics of the point pollution sources is presented. It can be used to find the main physical characteristics of them. The main physical characteristics of these sources are top inside source diameter and physical height. The top inside source diameter is calculated from gas flow-rate. For reckoning the physical height of the source one takes into account the relation given by the proportionality factor, defined as ratio between the plume rise and physical height of the source. The plume rise depends on the gas exit velocity and gas temperature. That relation is necessary for diminishing the environmental pollution when the production capacity of the plant varies, in comparison with the nominal one.

  10. Biomarkers of genotoxicity of urban air pollution. Overview and descriptive data from a molecular epidemiology study on populations exposed to moderate-to-low levels of polycyclic aromatic hydrocarbons: the AULIS project

    DEFF Research Database (Denmark)

    Kyrtopoulos, S.A.; Georgiadis, P.; Autrup, H.;

    2001-01-01

    inconclusive results, partly because of the absence of adequate data on personal exposure, covering a time-window which is appropriate for the biomarkers being examined, as well as a battery of biomarkers reflecting different stages of the carcinogenic process. In the present paper, the potential of biomarker......-based population studies to aid the assessment of the genotoxic and carcinogenic effects of urban air pollution is reviewed by reference to the achievements and limitations of earlier reported studies. The design and methodology adopted in a recently completed large-scale population study, carried out in the...

  11. Microbial degradation of monocyclic and polycyclic aromatic hydrocarbons in case of limited pollutant availability with nitrate as a potential electron acceptor; Der mikrobielle Abbau mono- und polyzyklischer aromatischer Kohlenwasserstoffe bei einer begrenzten Schadstoffverfuegbarkeit mit Nitrat als potentiellem Elektronenakzeptor

    Energy Technology Data Exchange (ETDEWEB)

    Linke, C.

    2001-07-01

    The possibility of using natural degradation processes for long-term remediation of tar oil contaminated sites was investigated. Field studies have shown that microbial decomposition of pollutants does take place in many sites but that it is limited by limited availability of pollutants and oxygen in soil. The investigations focused on the activation of BTEX and PAH degradation in situ by nitrate in the absence or in the presence of oxygen. Tensides should be used in order to enhance the availability of pollutants in water, especially in the case of hardly water-soluble PAH. A large-scale experiment was carried out on tar oil contaminated terrain; it was found that the availability of oxygen and not of PAH is the limiting factor so that adding of surfactants will not improve pollutant degradation. In contrast, the adding of tensides would mean even higher concentrations of oxygen-depleting substances in soil. [German] In der vorliegenden Arbeit wurden im Hinblick auf langfristige Sanierungsstrategien fuer teeroelkontaminierte Standorte Moeglichkeiten der Nutzung natuerlicher Abbauvorgaenge untersucht. Zahlreiche Feldstudien belegen, dass ein mikrobieller Schadstoffabbau an vielen Standorten stattfindet, dieser jedoch sowohl durch eine begrenzte Schadstoffverfuegbarkeit als auch durch den im Untergrund nur begrenzt zur Verfuegung stehenden Sauerstoff limitiert wird. Ziel dieser Arbeit war es abzuklaeren, inwiefern ein BTEX- und PAK-Abbau in situ auch in Abwesenheit von Sauerstoff durch Nitrat allein oder durch Nitrat in Kombination mit Sauerstoff aktiviert werden kann. Um insbesondere fuer die schlecht wasserloeslichen PAK eine ausreichende Schadstoffverfuegbarkeit zu gewaehrleisten, sollten auch Tenside zur Erhoehung der im Wasser vorliegenden Schadstoffmenge eingesetzt werden. Aufbauend auf die Laboruntersuchungen wurde im Rahmen von VEGAS{sup ix} ein Grossversuch zum mikrobiellen PAK-Abbau im Abstrom einer simulierten Teeroelkontamination durchgefuehrt

  12. Intelligent Exit-Selection Behaviors during a Room Evacuation

    Institute of Scientific and Technical Information of China (English)

    Zarita Zainuddin; Lim Eng Aik

    2012-01-01

    A modified version of the existing cellular automata (CA) model is proposed to simulate an evacuation procedure in a classroom with and without obstacles. Based on the numerous literature on the implementation of CA in modeling evacuation motions, it is notable that most of the published studies do not take into account the pedestrian's ability to select the exit route in their models. To resolve these issues, we develop a CA model incorporating a probabilistic neural network for determining the decision-making ability of the pedestrians, and simulate an exit-selection phenomenon in the simulation. Intelligent exit-selection behavior is observed in our model. From the simulation results, it is observed that occupants tend to select the exit closest to them when the density is low, but if the density is high they will go to an aiternative exit so as to avoid a long wait. This reflects the fact that occupants may not fully utilize multiple exits during evacuation. The improvement in our proposed model is valuable for further study and for upgrading the safety aspects of building designs.%A modified version of the existing cellular automata (CA) model is proposed to simulate an evacuation procedure in a classroom with and without obstacles.Based on the numerous literature on the implementation of CA in modeling evacuation motions,it is notable that most of the published studies do not take into account the pedestrian's ability to select the exit route in their models.To resolve these issues,we develop a CA model incorporating a probabilistic neural network for determining the decision-making ability of the pedestrians,and simulate an exit-selection phenomenon in the simulation.Intelligent exit-selection behavior is observed in our model.From the simulation results,it is observed that occupants tend to select the exit closest to them when the density is low,but if the density is high they will go to an alternative exit so as to avoid a long wait.This reflects the fact

  13. Jet Engine Nozzle Exit Configurations and Associated Systems and Methods

    Science.gov (United States)

    Mengle, Vinod G. (Inventor)

    2013-01-01

    Nozzle exit configurations and associated systems and methods are disclosed. An aircraft system in accordance with one embodiment includes a jet engine exhaust nozzle having an internal flow surface and an exit aperture, with the exit aperture having a perimeter that includes multiple projections extending in an aft direction. Aft portions of individual neighboring projections are spaced apart from each other by a gap, and a geometric feature of the multiple can change in a monotonic manner along at least a portion of the perimeter.

  14. Surgical management of Novacor drive-line exit site infections.

    Science.gov (United States)

    Pasque, Michael K; Hanselman, Tina; Shelton, Kim; Kehoe-Huck, Beth A; Hedges, Robyn; Cassivi, Stephen D; Ewald, Gregory A; Rogers, Joseph G

    2002-10-01

    Implantable left ventricular assist device (LVAD) drive-line exit site infection, an expected consequence of currently available device use, continues to be a significant limiting factor in long-term support. We theorize that the mechanism behind the establishment of the most chronic exit site infections involves a shearing torsion injury that disrupts the tissue adherence interface with the drive-line. The resulting neo-epithelialized drainage tract prevents permanent clearance of the infection with antibiotics alone. The proposed treatment strategy of established infections involves aggressive surgical excision of the involved exit site. PMID:12400795

  15. Entry and Exit Dynamics of Nascent Business Owners

    DEFF Research Database (Denmark)

    Rocha, Vera; Carneiro, Anabela; Varum, Celeste

    2015-01-01

    This paper reports a comprehensive study on the dynamics of nascent business owners using a unique longitudinal matched employer–employee dataset. We follow over 157,000 individuals who leave paid employment and become business owners during the period 1992–2007. The contributions of this paper are...... twofold. First, we analyze both entry and exit, identifying and characterizing different profiles of individuals leaving paid employment to become business owners, and distinguishing exits by dissolution from exits by ownership transfer. Second, we provide new evidence on how particular experiences in the...... labor market and entry modes shape the post-entry dynamics of nascent business owners. By differentiating between different entry and exit routes, this paper provides new evidence on different human capital patterns among nascent business owners and on key determinants of entrepreneurial survival. Our...

  16. Screening of anthropogenic compounds in polluted sediments and soils

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Leeuw, J.W. de; Leer, E.W.B. de; Schuyl, P.J.W.

    1986-01-01

    The use of flash evaporation and pyrolysis gas chromatography- mass spectrometry as a fast screening procedure for anthropogenic substances In environmental samples is demonstrated by the analysis of polluted soil and sediment samples. Polycyclic aromatic hydrocarbons, haloorganics, aliphatlc hydroc

  17. International Competition and Small-Firm Exit in US Manufacturing

    OpenAIRE

    Robert M. Feinberg

    2013-01-01

    This study analyzes both the determinants of small firm exit rates in US manufacturing over the 1989–2004 period, especially the reaction of domestic firms to the nature of foreign competition as measured by industry-specific real exchange rate movements (interacted with import penetration by industry). These international pressures seem to lead to increased rates of smallest-firm exit in manufacturing, though the magnitudes of these effects are smaller than sometimes discussed. However, high...

  18. A Novel Pathway that Coordinates Mitotic Exit with Spindle Position

    OpenAIRE

    Nelson, Scott A.; Cooper, John A.

    2007-01-01

    In budding yeast, the spindle position checkpoint (SPC) delays mitotic exit until the mitotic spindle moves into the neck between the mother and bud. This checkpoint works by inhibiting the mitotic exit network (MEN), a signaling cascade initiated and controlled by Tem1, a small GTPase. Tem1 is regulated by a putative guanine exchange factor, Lte1, but the function and regulation of Lte1 remains poorly understood. Here, we identify novel components of the checkpoint that operate upstream of L...

  19. Exit Interview-Consultation for Research Validation and Dissemination

    OpenAIRE

    Utley-Smith, Queen; Bailey, Donald; Ammarell, Natalie; Corazzini, Kirsten; Colón-Emeric, Cathleen S.; Lekan-Rutledge, Deborah; Piven, Mary L.; Anderson, Ruth A.

    2006-01-01

    Dissemination of research findings to practice and maintaining rigor and validity in qualitative research is a continuing challenge for nurse researchers. Using three nursing home case studies as examples, we describe how exit interview-consultation was used as: (1) a validation strategy, and; (2) as a rapid research dissemination tool that is particularly useful for nursing systems research. Through an exit interview–consultation method, researchers validated inferences made from qualitative...

  20. Central School Exit Exams and Labor-Market Outcomes

    OpenAIRE

    Piopiunik, Marc; Schwerdt, Guido; Woessmann, Ludger

    2012-01-01

    Many countries use centralized exit exams as a governance devise of the school system. While abundant evidence suggests positive effects of central exams on achievement tests, previous research on university-bound students shows no effects on subsequent earnings. We suggest that labor-market effects may be more imminent for students leaving school directly for the labor market and, on rigid labor markets, for unemployment. Exploiting variation in exit-exam systems across German states, we fin...

  1. Polyimidazoles via aromatic nucleophilic displacement

    Science.gov (United States)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor)

    1992-01-01

    Polyimidazoles (PI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl) imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as N,N-dimethyl acetamide, sulfolane, N-methylpyrrolidinone, dimethylsulfoxide, or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl) imidazole monomers are prepared by reacting an aromatic aldehyde with a dimethoxybenzil or by reacting an aromatic dialdehyde with a methoxybenzil in the presence of ammonium acetate. The di(methoxyphenyl) imidazole is subsequently treated with aqueous hydrobromic acid to give the di(hydroxphenyl) imidazole monomer. This synthetic route has provided high molecular weight PI of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides and dinitro compounds.

  2. Draft Genome Sequence of Pseudomonas sp. Strain 10-1B, a Polycyclic Aromatic Hydrocarbon Degrader in Contaminated Soil

    OpenAIRE

    Bello-Akinosho, Maryam; Adeleke, Rasheed; Swanevelder, Dirk; Thantsha, Mapitsi

    2015-01-01

    Pseudomonas sp. strain 10-1B was isolated from artificially polluted soil after selective enrichment. Its draft genome consists of several predicted genes that are involved in the hydroxylation of the aromatic ring, which is the rate-limiting step in the biodegradation of polycyclic aromatic hydrocarbons.

  3. Noise Pollution

    Science.gov (United States)

    ... EPA Home Air and Radiation Noise Pollution Noise Pollution This page has moved. You should be immediately ... gov/clean-air-act-overview/title-iv-noise-pollution Local Navigation Air & Radiation Home Basic Information Where ...

  4. Water Pollution

    Science.gov (United States)

    Bowen, H. J. M.

    1975-01-01

    Deals with water pollution in the following categories: a global view, self purification, local pollution, difficulties in chemical analysis, and remedies for water pollution. Emphasizes the extent to which man's activities have modified the cycles of certain elements. (GS)

  5. Air Pollution

    Science.gov (United States)

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, ... a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  6. Noise Pollution

    Science.gov (United States)

    ... Overview » Title IV - Noise Pollution Title IV - Noise Pollution The 1990 Clean Air Act Amendments added a ... abatement 7642 Authorization of appropriations What is Noise Pollution? The traditional definition of noise is “unwanted or ...

  7. Air Pollution

    Science.gov (United States)

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, pollen and ... Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, ...

  8. Aromatic molecules as spintronic devices

    International Nuclear Information System (INIS)

    In this paper, we study the spin-dependent electron transport through aromatic molecular chains attached to two semi-infinite leads. We model this system taking into account different geometrical configurations which are all characterized by a tight binding Hamiltonian. Based on the Green's function approach with a Landauer formalism, we find spin-dependent transport in short aromatic molecules by applying external magnetic fields. Additionally, we find that the magnetoresistance of aromatic molecules can reach different values, which are dependent on the variations in the applied magnetic field, length of the molecules, and the interactions between the contacts and the aromatic molecule

  9. Improvement of the Vertical Dispersion of Pollutants Resulting From Chimneys by Thermosiphon Effect

    OpenAIRE

    A. O.M. Mahmoud; J. Zinoubi; R.B. Maad; A. Belghith

    2006-01-01

    The dispersion of pollutants, resulting from industrial chimneys, in the surrounding atmosphere made the interest in realizing emitting conditions appears. It also encourages the vertical dispersion of these pollutants. At a given wind velocity, the height of this dispersion is essentially a function of the thermal power and the flow rate at the chimney exit. To improve these qualities, we propose a system that could be integrated to the industrial chimney exit. An open-ended vertical cylinde...

  10. Tracing organic gaseous pollutants in the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Rymen, T.A.A.

    1979-01-01

    Methods of tracing various air pollutants, including low molecular weight hydrocarbons, chlorinated hydrocarbons, and aromatics, are discussed. Gas chromatography and flame ionization, or electron capture detection were used to detect the pollutants in ambient air, depending on which method was more sensitive for the pollutant in question. Analysis, calibration procedures, and sampling techniques (both automatic field operation and discontinuous laboratory control), were studied for samples collected near a vinyl chloride plant, and in an area with intensive paint industry. The combination of gas-solid or gas-liquid chromatography with a highly sensitive detector offers a versatile analytic method of measuring organic air pollutants. (6 diagrams, 6 graphs, 16 references, 9 tables)

  11. "Carbo-aromaticity" and novel carbo-aromatic compounds.

    Science.gov (United States)

    Cocq, Kévin; Lepetit, Christine; Maraval, Valérie; Chauvin, Remi

    2015-09-21

    While the concept of aromaticity is being more and more precisely delineated, the category of "aromatic compounds" is being more and more expanded. This is illustrated by an introductory highlight of the various types of "aromaticity" previously invoked, and by a focus on the recently proposed "aromatic character" of the "two-membered rings" of the acetylene and butatriene molecules. This serves as a general foundation for the definition of "carbo-aromaticity", the relevance of which is surveyed through recent results in the synthetic, physical, and theoretical chemistry of carbo-mers and in particular macrocyclic-polycyclic representatives constituting a natural family of "novel aromatic compounds". With respect to their parent molecules, carbo-mers are constitutionally defined as "carbon-enriched", and can also be functionally regarded as "π-electron-enriched". This is exemplified by recent experimental and theoretical results on functional, aromatic, rigid, σ,π-macrocyclic carbo-benzene archetypes of various substitution patterns, with emphasis on the quadrupolar pattern. For the purpose of comparison, several types of non-aromatic references of carbo-benzenes are then considered, i.e. freely rotating σ,π-acyclic carbo-n-butadienes and flexible σ-cyclic, π-acyclic carbo-cyclohexadienes, and to "pro-aromatic" congeners, i.e. rigid σ,π-macrocyclic carbo-quinoids. It is shown that functional carbo-mers are entering the field of "molecular materials" for properties such as linear or nonlinear optical properties (e.g. dichromism and two-photon absorption) and single molecule conductivity. Since total or partial carbo-mers of aromatic carbon-allotropes of infinite size such as graphene (graphynes and graphdiynes) and graphite ("graphitynes") have long been addressed at the theoretical or conceptual level, recent predictive advances on the electrical, optical and mechanical properties of such carbo-materials are surveyed. Very preliminary experimental results

  12. Mitotic Exit Control as an Evolved Complex System

    Energy Technology Data Exchange (ETDEWEB)

    Bosl, W; Li, R

    2005-04-25

    The exit from mitosis is the last critical decision a cell has to make during a division cycle. A complex regulatory system has evolved to evaluate the success of mitotic events and control this decision. Whereas outstanding genetic work in yeast has led to rapid discovery of a large number of interacting genes involved in the control of mitotic exit, it has also become increasingly difficult to comprehend the logic and mechanistic features embedded in the complex molecular network. Our view is that this difficulty stems in part from the attempt to explain mitotic exit control using concepts from traditional top-down engineering design, and that exciting new results from evolutionary engineering design applied to networks and electronic circuits may lend better insights. We focus on four particularly intriguing features of the mitotic exit control system: the two-stepped release of Cdc14; the self-activating nature of Tem1 GTPase; the spatial sensor associated with the spindle pole body; and the extensive redundancy in the mitotic exit network. We attempt to examine these design features from the perspective of evolutionary design and complex system engineering.

  13. Polycyclic aromatic hydrocarbon (PAH) occurrence and remediation methods

    OpenAIRE

    Henner, Pascale; Schiavon, Michel; Morel, Jean-Louis; Lichtfouse, Eric

    1997-01-01

    International audience Polycyclic aromatic hydrocarbons (PAHs) are potentially mutagenic and carcinogenic substances occurring at various concentrations in atmosphere, soils, waters and sediments. PAHs, inherited both from natural and anthropogenic processes, are persistent organic pollutants (POP) due to their chemical stability and biodegradation resistance. The increase of road transportation, and of industrial and agricultural activities has led to a notable build up of PAH amounts in ...

  14. Polycyclic aromatic hydrocarbons in atmospheric depositions around the Venice Lagoon

    OpenAIRE

    Rossini, Paolo; Matteucci, Gabriele; Raccanelli, Stefano; Favotto, Maurizio; Guerzoni, Stefano; Gattolin, Massimo

    2007-01-01

    Studies have revealed the potential risks to which human health and ecosystems are exposed in the Venice Lagoon, due to the atmospheric deposition of persistent pollutants such as trace metals and organic compounds. A total of 77 atmospheric bulk deposition samples were collected monthly from April 2002 to December 2004, from three sites located in the cities of Mestre and Venice, and inside the industrial area of Porto Marghera. Samples were analyzed by HRGC/HRMS for polycyclic aromatic hydr...

  15. Degradation of aromatic compounds in plants grown under aseptic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mithaishvili, T.; Ugrekhelidze, D.; Tsereteli, B.; Sadunishvili, T.; Kvesitadze, G. [Durmishidze Inst. of Biochemistry and Biotechnology, Academy of Sciences of Georgia, Tbilisi (Georgia); Scalla, R. [Lab. des Xenobiotiques, INRA, Toulouse (France)

    2005-02-01

    The aim of the work is to investigate the ability of higher plants to absorb and detoxify environmental pollutants - aromatic compounds via aromatic ring cleavage. Transformation of {sup 14}C specifically labelled benzene derivatives, [1-6-{sup 14}C]-nitrobenzene, [1-6-{sup 14}C]-aniline, [1-{sup 14}C]- and [7-{sup 14}C]-benzoic acid, in axenic seedlings of maize (Zea mays L.), kidney bean (Phaseolus vulgaris L.), pea (Pisum sativum L.) and pumpkin (Cucurbita pepo L.) were studied. After penetration in plants, the above xenobiotics are transformed by oxidative or reductive reactions, conjugation with cell endogenous compounds, and binding to biopolymers. The initial stage of oxidative degradation consists in hydroxylation reactions. The aromatic ring can then be cleaved and degraded into organic acids of the Krebs cycle. Ring cleavage is accompanied by {sup 14}CO{sub 2} evolution. Aromatic ring cleavage in plants has thus been demonstrated for different xenobiotics carrying different substitutions on their benzene ring. Conjugation with low molecular peptides is the main pathway of aromatic xenobiotics detoxification. Peptide conjugates are formed both by the initial xenobiotics (except nitrobenzene) and by intermediate transformation products. The chemical nature of the radioactive fragment and the amino acid composition of peptides participating in conjugation were identified. (orig.)

  16. Near field and exit wave computations for electron microscopy.

    Science.gov (United States)

    Howie, A

    2013-11-01

    The partial wave phase shift formalism of atomic scattering is applied to compute exit wave functions for isolated Au and Si atoms under both plane wave and focused probe illumination. Connections between the far field and near field (exit) waves are clarified. This approach treats the Coulomb singularity properly though at 100 keV large numbers of phase shifts are required. In principle any form of incident wave can be handled so it may provide a means for testing traditional scattering theories used in electron microscopy. By applying the analysis to an atom embedded in a constant potential rather than free space, exit spheres of radius half the interatomic spacing can be used. PMID:23726769

  17. Gas turbine combustor exit piece with hinged connections

    Energy Technology Data Exchange (ETDEWEB)

    Charron, Richard C.; Pankey, William W.

    2016-04-26

    An exit piece (66) with an inlet throat (67) that conducts a combustion gas flow (36A) in a path (82) from a combustor (63) to an annular chamber (68) that feeds the first blade section (37) of a gas turbine (26). The exit piece further includes an outlet portion (69) that forms a circumferential segment of the annular chamber. The outlet portion interconnects with adjacent outlet portions by hinges (78A, 78B, 80A, 80B). Each hinge may have a hinge axis (82A, 82B) parallel to a centerline (21) of the turbine. Respective gas flows (36A) are configured by an assembly (60) of the exit pieces to converge on the feed chamber (68) into a uniform helical flow that drives the first blade section with minimal circumferential variations in force.

  18. Effects of ribosomal exit tunnel on protein's cotranslational folding

    International Nuclear Information System (INIS)

    In vivo, folding of many proteins occurs during their synthesis in the ribosome and continues after they have escaped from the ribosomal exit tunnel. In this research, we investigate the confinement effects of the ribosome on the cotranslational folding of three proteins, of PDB codes 1PGA, 1CRN and 2RJX, by using a coarse-grained model and molecular dynamics simulation. The exit tunnel is modeled as a hollow cylinder attached to a flat wall, whereas a Go-like model is adopted for the proteins. Our results show that the exit tunnel has a strong effect on the folding mechanism by setting an order by which the secondary and tertiary structures are formed. For protein 1PGA, the folding follows two different folding routes. The presence of the tunnel also improves the foldability of protein. (author)

  19. Thermonuclear operation mode and entrance/exit monitoring system

    International Nuclear Information System (INIS)

    The present invention provides a processing system when the entrance/exit of each of buildings or chambers are monitored based on contents of control for the equipments in each operation mode of a thermonuclear experimental device, and provides a processing system when abnormalities are detected in an early stage. Namely, interlock signals for on-off conditions or each of the entrance/exit in each operation mode are inputted to a control device. With such procedures, contents of processing at entrance/exit of a power source building, an experimental building, and a main chamber in a certain operation mode (on-off condition, etc.) are determined, and the logic can be reflected on the control device. According to the present invention, a safety system for the operation can be ensured sufficiently, coping with increased scale of the thermonuclear experimental device, complication of the control system or temporary change of the operation control system. (I.S.)

  20. Comparison of exit time moment spectra for extrinsic metric balls

    DEFF Research Database (Denmark)

    Hurtado, Ana; Markvorsen, Steen; Palmer, Vicente

    We prove explicit upper and lower bounds for the $L^1$-moment spectra for the Brownian motion exit time from extrinsic metric balls of submanifolds $P^m$ in ambient Riemannian spaces $N^{n}$. We assume that $P$ and $N$ both have controlled radial curvatures (mean curvature and sectional curvature......, respectively) as viewed from a pole in $N$. The bounds for the exit moment spectra are given in terms of the corresponding spectra for geodesic metric balls in suitably warped product model spaces. The bounds are sharp in the sense that equalities are obtained in characteristic cases. As a corollary we also...

  1. Chronic oil pollution in the Bosphorus, Sea of Marmara and Dardanelles

    International Nuclear Information System (INIS)

    Oil pollution was measured at the entrance and exit of the Bosphorus and Dardanelles monthly and seasonally at two stations in the Black Sea and four stations in the Sea of Marmara in 1995-1996. In 1996, the oil level increased; in the Bosphorus, in the surface water, 4.8 times at the entrance, 2.9 times at the exit, in 10 m 3.2 times in the entrance, 9.2 times in exit, in the Sea of Marmara 2.8 times in the surface water, 42.9 times in 10 m. In the Dardanelles 8.3 times at entrances and 7.7 times at the exit and in 10 m 2.5 times at the entrance and 5.3 times at the exit. The results showed that the pollution has increased in the Turkish Straits throughout the years. (author)

  2. Study of remobilization polycyclic aromatic hydrocarbons (PAHs) in contaminated matrices

    International Nuclear Information System (INIS)

    Polycyclic aromatic hydrocarbons (PAHs) originate from many pyrolysis processes. They are widespread environmental pollutants because some of them present toxic and genotoxic properties. In coal pyrolysis sites such as former manufactured gas plants and coke production plants, coal tar is a major source of PAHs. The management of such sites requires better understanding of the mechanisms that control release of PAHs to the biosphere. Determining total PAH concentrations is not sufficient since it does not inform about the pollutants availability to environmental processes. The fate and transport of PAHs in soil are governed by sorption and microbial processes which are well documented. Globally, enhancing retention of the compounds by a solid matrix reduces the risk of pollutant dispersion, but decreases their accessibility to microbial microflora. Conversely, the remobilization of organics from contaminated solid matrices represents a potential hazard since these pollutants can reach groundwater resources. However the available data are often obtained from laboratory experiments in which many field parameters can not be taken into account (long term, temperature, co-pollution, ageing phenomenon, heterogenous distribution of pollution). The present work focuses on the influence assessment and understanding of some of these parameters on PAHs remobilization from heavily polluted matrices in near-field conditions (industrial contaminated matrices, high contact time, ..). Results concerning effects of temperature and physical state of pollution (dispersed among the soil or condensed in small clusters or in coal tar) are presented. (authors)

  3. Selling, Passing on or Closing? Determinants of Entrepreneurial Intentions on Exit Modes

    OpenAIRE

    Martina Battisti; Hiroyuki Okamuro

    2010-01-01

    Exit is an important part of the entrepreneurial lifecycle. In contrast to numerous previous studies on entry, however, little attention has been paid to entrepreneurial exit, and much less on exit modes thus far. Using a recent original survey data on small business owners in New Zealand, where a large majority of them prefer selling their firms when they exit, we empirically investigate the determinants of intended entrepreneurial exit modes: selling out, succession, or closure. Estimation ...

  4. 苏南地区农田表层土壤中多环芳烃和酞酸酯的污染特征及来源%Pollution Characteristics and Sources of Polycyclic Aromatic Hydrocarbons and Phthalic Acid Esters in Agricultural Surface Soil from the Southern Jiangsu Province, China

    Institute of Scientific and Technical Information of China (English)

    张利飞; 杨文龙; 董亮; 黄业茹; 史双昕; 张烃; 周丽

    2011-01-01

    采用气相色谱质谱(GC-MS)法测定了苏南地区13个农田表层土壤样品中的多环芳烃(PAHs)和酞酸酯(PAEs)污染物,分析比较了不同区域农田表层土壤,尤其是来自钢铁企业周边的表层土壤中PAHs和PAEs的污染特征及其来源.结果表明,苏南地区农田上壤中总PAHs和总PAEs的浓度分别在147~40 300 μg·kg-1和0.575~762 μg· kg-1之间,其中钢铁厂周边的平均浓度分别为6 130 μg· kg-1和47.4 μg· kg-1.土壤样品中苯并(a)芘的浓度与总PAHs的浓度显著相关,高分子量PAHs在钢铁厂周边表土中含量较高,钢铁冶炼焦化和烧结等工序是其污染来源.酞酸正丁酯(DBP)和酞酸乙基己基酯是苏南地区农田土壤中含量最高的两种PAEs类物质,钢铁厂周边有较高的DBP检出可能与炼钢、冷轧和炼铁等工序有关.本研究将为经济高速发展地区农田土壤环境质量评价、农产品安全生产及土壤污染防治对策的制定提供科学依据.%Polycyclic aromatic hydrocarbons(PAHs) and phthalic acid esters(PAEs) are ubiquitous in the environment. They were the key pollutants of the national survey of soil pollution. The Southern Jiangsu Province is the main part of the Yangtze River Delta, which was one of the most rapidly developing areas not only in China but also in the world. Agricultural pollution in the Southern Jiangsu Province is more concerned with the economic development. In this study, three cities including Suzhou, Wuxi, and Nantong in the Southern Jiangsu Province were selected for the determination of PAHs and PAEs. Thirteen agricultural surface soil samples, including five samples from an iron and steel factory were collected. The pollution characteristics and potential sources of PAHs and PAEs were investigated. The total PAHs and PAEs concentrations varied from 147 to 40 300 μg·kg-1, and from 0.575 to 762 μg·kg-1, respectively. Concentration of benzo[a] pyrene and the total PAHs of the surface soil

  5. Relationship Between Accumulation and Influx of Pollutants in Highway Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby; Larsen, Torben; Rasmussen, Michael R.

    The paper discusses the long term mass balance of pollutants in highway ponds. The accumulations of five polycyclic aromatic hydrocarbons (PAHs) and six heavy metals have been measured in eight Danish detention ponds, which receive runoff from highways only. For each pollutant the accumulation has...

  6. After exit: Academic achievement patterns of former English language learners.

    Directory of Open Access Journals (Sweden)

    Ester J. de Jong

    2004-09-01

    Full Text Available With few exceptions, accountability systems for programs for English language learners (ELLs have focused on the achievement patterns of ELLs who are still considered “limited English proficient” and program evaluations have been unable to answer the question whether ELLs actually catch up with English proficient peers after attending a bilingual or English as a Second Language (ESL program. Disaggregating data for former ELLs can therefore provide important information for long-term district and program accountability. The study was concerned with the achievement patterns in English language arts, Math, and Science of former ELLs who attended a bilingual and a English as a Second Language (ESL program. It also explored whether length of program participation and grade level exited played a significant role in predicting academic achievement patterns for these exited students. Results indicate that 4th grade students more closely paralleled non- ELL students’ achievement patterns than 8th grade students, particularly for the BE students. While length of program participation is not a significant predictor of former ELLs’ academic success, exit grade does emerge as an important variable to take into consideration in setting exit guidelines.

  7. Limitations of detecting inadequate core cooling with core exit thermocouples

    International Nuclear Information System (INIS)

    USNRC has suggested that the thermocouples (TCs) currently installed at the flow exit of a PWR core could be used to detect a condition of inadequate core cooling (ICC). The use of these TCs has been assumed in the USNRC Regulatory Guide 1.97. PWR vendors have responded to this guideline by proposing ICC instrumentation and procedure packages that include the use of core-exit TCs as a principal means of ICC detection. The core-exit TCs are judged to be able to detect an ICC condition because steam in the core will be superheated by the fuel rods and then flow past the TCs during an accident. The detection of superheat in the fluid stream constitutes the indirect detection of a core uncovery and heatup, or ICC. Data have been analyzed from four experiments conducted in the Loss-of-Fluid Test (LOFT) facility and the results indicate that there are two limitations to the detection of ICC by core exit TCs that should be resolved before reliance can be placed in the measurement. The LOFT TCs are described and these limitations are discussed in this paper

  8. EXIT Chart Analysis of Binary Message-Passing Decoders

    DEFF Research Database (Denmark)

    Lechner, Gottfried; Pedersen, Troels; Kramer, Gerhard

    2007-01-01

    extended to channels with larger output alphabets. By increasing the output alphabet from hard decisions to four symbols, a gain of more than 1.0 dB is achieved using optimized codes. For this code optimization, the mixing property of EXIT functions has to be modified to the case of binary message...

  9. Comparison of exit time moment spectra for extrinsic metric balls

    DEFF Research Database (Denmark)

    Hurtado, Ana; Markvorsen, Steen; Palmer, Vicente

    2012-01-01

    We prove explicit upper and lower bounds for the $L^1$-moment spectra for the Brownian motion exit time from extrinsic metric balls of submanifolds $P^m$ in ambient Riemannian spaces $N^n$. We assume that $P$ and $N$ both have controlled radial curvatures (mean curvature and sectional curvature, ...

  10. "The MDGs and Exit Time: The Case of the Philippines "

    OpenAIRE

    Yasuyuki Sawada; Estudillo, Jonna P.

    2005-01-01

    This paper evaluates whether the Philippines will be able to halve the incidence of poverty between 1990 and 2015. Using the concept of exit time and household-level data, we found that the Philippines will be unlikely to do so.

  11. The Exit Poll: An Environmental Scanning Technique for School Districts.

    Science.gov (United States)

    House, Jess E.

    1989-01-01

    Exit polling of school district election returns is a form of environmental scanning that can provide information needed for strategic planning and be used to increase the effectiveness of school election campaigns. This technique is recommended for all school districts dependent on voter approval to meet revenue needs. (11 references) (MLH)

  12. Some Features of Aerodynamics of Cyclonic Chamber with Free Exit

    Directory of Open Access Journals (Sweden)

    A. N. Orekhov

    2014-06-01

    Full Text Available The paper cites results of an experimental research in aerodynamics of a cyclonic chamber with a free exit that has a large relative length. Distributions of aerodynamic stream characteristics depending on geometry of working volume of the cyclonic chamber are given in the paper. Calculative dependences are proposed in the paper.

  13. How extremist experiences become valuable knowledge in EXIT programmers

    DEFF Research Database (Denmark)

    Christensen, Tina Wilchen

    2015-01-01

    On the basis of a neo-Vygotskian approach the article analyses how former neo-Nazis, together with other staff at Fryshuset, a youth centre in Stockholm, Sweden, have developed the organisation EXIT, which helps people leave the extremist right. The article describes the processes former neo-Nazis...

  14. 14 CFR 29.811 - Emergency exit marking.

    Science.gov (United States)

    2010-01-01

    ... rotary motion of the handle, by— (i) A red arrow, with a shaft at least three-fourths inch wide and a... equal to three-fourths of the handle length; and (ii) The word “open” in red letters 1 inch high, placed... the word “Exit.”...

  15. Congenital Cervical Teratoma: Anaesthetic Management (The EXIT Procedure

    Directory of Open Access Journals (Sweden)

    Ferruh Bilgin

    2009-01-01

    Full Text Available Ex utero intrapartum treatment (EXIT is a procedure performed during caesarean section with preservation of fetal-placental circulation, which allows the safe handling of fetal airways with risk of airways obstruction. This report aimed at describing a case of anaesthesia for EXIT in a fetus with cervical teratoma. A 30-year-old woman, 70 kg, 160 cm, gravida 2, para 1, was followed because of polyhydramniosis diagnosed at 24 weeks′ gestation. During a routine ultrasonographic examination at 35 weeks′ gestation, it was noticed that the fetus had a tumoral mass on the anterior neck, the mass had cystic and calcified components and with a size of was 10 x 6 x5 cm. The patient with physical status ASA I, was submitted to caesarean section under general anaesthesia with mechanically controlled ventilation for exutero intrapartum treatment (EXIT. Anaesthesia was induced in rapid sequence with fentanyl, propofol and rocuronium and was maintained with isoflurane in 2.5 at 3 % in O 2 and N 2 O (50%. After hysterotomy, fetus was partially released assuring uterus-placental circulation, followed by fetal laryngoscopy and tracheal intuba-tion. The infant was intubated with an uncuffed, size 2.5 endotracheal tube. Excision of the mass was performed under general anaesthesia. After surgical intervention, on the fourth postoperative day, the infant was extubated and the newborn was discharged to the pediatric neonatal unit and on the seventh day postoperatively to home without complications. Major recommendations for EXIT are maternal-fetal safety, uterine relaxation to maintain uterine volume and uterus-placental circulation, and fetal immobility to help airway handling. We report one case of cervical teratoma managed successfully with EXIT procedure.

  16. Water pollution

    OpenAIRE

    Institute, Marine

    2013-01-01

    Students will learn about what causes water pollution and how to be environmentally aware. *Note: Students should understand the concept of the water cycle before moving onto water pollution (see Lesson Plan “Oceans all Around Us”).

  17. Polybenzimidazoles Via Aromatic Nucleophilic Displacement

    Science.gov (United States)

    Connell, John W. (Inventor); Hergerrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1997-01-01

    Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenylbenzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl)benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl)benzimidazoles are synthesized by reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  18. Air Pollution and the skin

    Directory of Open Access Journals (Sweden)

    Eleni eDrakaki

    2014-05-01

    Full Text Available The increase of air pollution over the years has major effects on the human skin. The skin is exposed to ultraviolet radiation (UVR and environmental air pollutants such as polycyclic aromatic hydrocarbons (PAHs, volatile organic compounds (VOCs, oxides, particulate matter (PM, ozone (O3 and cigarette smoke. Although human skin acts as a biological shield against pro-oxidative chemical and physical air pollutants, the prolonged or repetitive exposure to high levels of these pollutants may have profound negative effects on the skin. Exposure of the skin to air pollutants has been associated with skin aging and inflammatory or allergic skin conditions such as atopic dermatitis, eczema, psoriasis or acne, while skin cancer is among the most serious effects. On the other hand, some air pollutants (ie, ozone, nitrogen dioxide, and sulfur dioxide and scattering particulates (clouds and soot in the troposphere reduce the effects of shorter wavelength UVR and significant reductions in UV irradiance have been observed in polluted urban areas.

  19. Comparability of Semester and Exit Exam Grades: Long-Term Effect of the Implementation of State-Wide Exit Exams

    Science.gov (United States)

    Maag Merki, Katharina; Holmeier, Monika

    2015-01-01

    A goal in many countries is to institute state-wide exams to base student assessment more firmly on norms for all classes. This raises the question as to the extent to which greater standardization of grading practice can be reached by implementing state-wide exit exams. Since there is a lack of longitudinal studies, we analyzed the effect of the…

  20. Water Pollution

    International Nuclear Information System (INIS)

    This work is about the water pollution. The air and the water interaction cycles is the main idea of the geochemical pollution conception. In the water surface as well as in the deep aquifers we can found cough metals or minerals from the athmosferic air. The activities of mercury fluor and nitrates are important to the pollution study

  1. Air Pollution.

    Science.gov (United States)

    Barker, K.; And Others

    Pollution of the general environment, which exposes an entire population group for an indeterminate period of time, certainly constitutes a problem in public health. Serious aid pollution episodes have resulted in increased mortality and a possible relationship between chronic exposure to a polluted atmosphere and certain diseases has been…

  2. Bioassay of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Van Kirk, E.A.

    1980-08-01

    A positive relationship was found between the photodynamic activity of 24 polycyclic aromatic hydrocarbons versus published results on the mutagenicity, carcinogenicity, and initiation of unscheduled DNA synthesis. Metabolic activation of benzo(a)pyrene resulted in detection of increased mutagenesis in Paramecium tetraurelia as found also in the Ames Salmonella assay. The utility of P. tetraurelia as a biological detector of hazardous polycyclic aromatic hydrocarbons is discussed.

  3. Micropropagation of different aromatic plants

    OpenAIRE

    Koleva Gudeva, Liljana; Iljovska Tusev, Jasmina; Trajkova, Fidanka

    2014-01-01

    Aromatic plants have been used for centuries as species, natural flavor, raw material for essential-oil industry and other purposes. Micropropagation has advantage over conventional propagation because of high multiplication rate, but it depends on the performance of the starting material, media composition, phytohormones and environmental factors. In this study, aromatic plants as peppermint (Menta piperita L.) and Menta sp., rosemary (Rosmarinus sp.), rocket (Eruca sativa Mill.), coriand...

  4. 千岛湖表层沉积物中多环芳烃污染特征及生态风险评价%Pollution characteristics and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from Xin’anjiang Reservoir

    Institute of Scientific and Technical Information of China (English)

    张明; 唐访良; 吴志旭; 陈峰; 程新良; 徐建芬; 俞雅雲

    2014-01-01

    利用高效液相色谱法对采集于2012年12月的部分千岛湖表层沉积物中多环芳烃(PAHs)进行了分析。结果表明,千岛湖表层沉积物中共检出属于美国EPA优先控制16种PAHs中的15种,各采样点位PAHs总量的浓度范围在258~906ng/g(干重)之间,平均值为558ng/g,属低污染水平。空间分布特征受周边区域内点源污染和河流输入污染物影响。沉积物中的多环芳烃以高分子量组分为主,通过特征组分比例可确认其主要来源于周边地区煤炭、木材不完全燃烧及车船尾气排放。利用沉积物质量基准法、沉积物质量标准法分别对千岛湖表层沉积物中 PAHs 的风险评价表明,千岛湖沉积物中不存在严重的多环芳烃生态风险,但部分点位按照质量标准法评价已经超过临界效应浓度值,需加强监测查明污染源,并采取措施控制污染物输入。%Polycyclic aromatic hydrocarbons (PAHs) were quantitatively determined by HPLC in several surface sediment samples collected in December 2012 from Xin’anjiang Reservoir. The results showed that 15 of the 16 US EPA priority controlled PAHs were detected. Total concentrations of PAHs in surface sediments of the studied reservoir ranged from 258 to 906ng/g dry weight (dw), with average 558ng/g dw, lower pollution level. The distribution of PAHs is found to be influenced by riverine discharge and point-source pollution. The PAHs in the sediments were dominated by high molecular weight PAHs. According to the ratio of feature components, the PAHs in surface sediment from the Xin’anjiang Reservoir originated largely from coal and biomass incomplete combustion in the surrounding areas and exhaustion of boats or cars. In addition, the ecological risk of surface sediment in Xin’anjiang Reservoir was assessed with the methods of sediment quality guidelines and sediment quality standards (SQSs), and the result indicated that there was no great biological impact associated

  5. Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    Salama, Farid

    2010-01-01

    Carbonaceous materials play an important role in space. Polycyclic Aromatic Hydrocarbons (PAHs) are a ubiquitous component of the carbonaceous materials. PAHs are the best-known candidates to account for the IR emission bands. They are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge is to reproduce in the laboratory the physical conditions that exist in the emission and absorption interstellar zones. The harsh physical conditions of the ISM -low temperature, collisionless, strong UV radiation fields- are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions and radicals are formed from the neutral precursors in an isolated environment at low temperature and probed with high-sensitivity cavity ringdown spectroscopy in the NUV-NIR range. Carbon nanoparticles are also formed during the short residence time of the precursors in the plasma and are characterized with time-offlight mass spectrometry. These experiments provide unique information on the spectra of large carbonaceous molecules and ions in the gas phase that can now be directly compared to interstellar and circumstellar observations (IR emission bands, DIBs, extinction curve). These findings also hold great potential for understanding the formation process of interstellar carbonaceous grains. We will review recent progress in the experimental and theoretical studies of PAHs, compare the laboratory data with astronomical observations and discuss the global implications.

  6. Chapter 11: Biodegradation of Aromatic Pollutants by Ligninolytic Fungal Strains

    Czech Academy of Sciences Publication Activity Database

    Cajthaml, Tomáš; Svobodová, Kateřina

    Heidelberg: Springer-Verlag Berlin Heidelberg, 2011 - (Singh, S.), s. 291-316 ISBN 978-3-642-23788-1 R&D Projects: GA ČR GA525/09/1058; GA ČR GAP503/10/0408 Institutional research plan: CEZ:AV0Z50200510 Keywords : PAHs * PCBs * ligninolytic fungi Subject RIV: EE - Microbiology, Virology

  7. Anisotropy of thermal infrared exitance in sunflower canopies

    Science.gov (United States)

    Tha Paw u, Kyaw; Ustin, Susan L.; Zhang, Chang-An

    1989-01-01

    Anisotropy of thermal infrared exitance above and within a relatively closed fully irrigated sunflower canopy is detailed. Azimuthal variation in thermal infrared exitance above canopies was weakly (statistically) related to solar position and was comparable to or larger than errors in satellite-based canopy estimates. Anisotropy within canopies was significantly lower and decreased with canopy closure and depth into the canopy. Measured azimuthal isotropy within canopies supports the use of this assumption in radiative transfer models. Significant differences in canopy temperature measurements were found depending upon whether the instruments were within or above the canopy. These differences could produce errors of 20-35 percent in latent energy estimates during periods of high evapotranspiration (ET) and greater errors in periods of restricted ET.

  8. Composite Control of Precalciner Exit Temperature in Cement Rotary Kiln

    Institute of Scientific and Technical Information of China (English)

    赵晨; 诸静

    2003-01-01

    A composite control strategy for the precalciner exit temperature in cement kiln is introduced based on a mathematical model. In this model, the raw meal flow, coal powder flow and wind flow are taken as three input variables, the clinker fow and exit teperature of cement kiln are output variables, and other influencing factors are considered as disturbance. A composite control system is synthesied by integrating self-learning PID, fuzzy and feedforward function into a combined controller, and the arithmetics for the self-learning PID controller, fuzzy controller and feedforward controller are elaborated respectively. The control strategy has been realized by software in real practice at cement factory. Application results show that the composite control technology is superior to the general PID control in control effect, and is suitable to the industrial process control with slow parameter variation, nonlinearity and uncertainty.

  9. Customer Protest: Exit, Voice or Negative Word of Mouth

    Directory of Open Access Journals (Sweden)

    Solvang, B. K.

    2008-01-01

    Full Text Available Of the three forms of protest the propensity of word of mouth (WOM seems to be the most common, and the most exclusive form of protest seems to be exit. The propensity for voice lies in between. The costs linked to voice influence the propensity for WOM. The customers seem to do an evaluation between the three forms of protest, yet the rational picture of the customers should be moderated.Leaders should improve their treatment of the customers making complaints. The more they can treat customer complaints in an orderly and nice way the less informal negative word of mouth activity they will experience and they will reduce the exit propensity and lead the customers to the complain organisation. They should also ensure that their customers feel they get equal treatment by the staff.

  10. Graceful exit from a stringy landscape via MSSM inflation

    CERN Document Server

    Allahverdi, R; Mazumdar, A; Allahverdi, Rouzbeh; Frey, Andrew R.; Mazumdar, Anupam

    2007-01-01

    The cosmological evolution of the string landscape is expected to consist of multiple stages of old inflation with large cosmological constant ending by tunneling. Old inflation has a well known graceful exit problem as the observable universe becomes empty, devoid of any entropy. Simultaneously, in the quest for reheating the right degrees of freedom, it is important that the final stage of inflation ends within the Minimal Supersymmetric Standard Model (MSSM) sector. In this paper, we study how inflation of a MSSM flat direction can be embedded into the string theory landscape of metastable vacua. The fluctuations of the MSSM flat direction during old inflation create regions with initial conditions favorable for eternal and slow-roll inflation and provides a graceful exit from old inflation on the landscape. This resulting phase of MSSM inflation generates enough e-foldings of inflation to dilute any relics of old inflation while producing the observed amplitude of temperature anisotropy with a matching sp...

  11. Entrance, exit, and reentrance of one shot with a shotgun

    DEFF Research Database (Denmark)

    Gulmann, C; Hougen, H P

    1999-01-01

    The case being reported is one of a homicidal shotgun fatality with an unusual wound pattern. A 34-year-old man was shot at close range with a 12-gauge shotgun armed with No. 5 birdshot ammunition. The shot entered the left axillary region, exited through the left infraclavicular region, and...... thereafter penetrated the left side of the neck, causing tearing of the left common carotid artery and the right internal carotid artery. The entrance wound in the axilla was larger than the other wounds, and before autopsy it was believed that the shotgun had been fired twice, causing one wound in the neck...... and one wound perforating the infraclavicular region and exiting through the left axillary region. Thus, this case shows that unusual wound patterns in shotgun fatalities can easily lead to incorrect assumptions with regard to number and direction of shots fired unless thorough investigation is...

  12. The exit-time problem for a Markov jump process

    Energy Technology Data Exchange (ETDEWEB)

    Burch, N. [Gonzaga Univ., Spokane, WA (United States); D' Elia, Marta [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lehoucq, Richard B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-12-15

    The purpose of our paper is to consider the exit-time problem for a finite-range Markov jump process, i.e, the distance the particle can jump is bounded independent of its location. Such jump diffusions are expedient models for anomalous transport exhibiting super-diffusion or nonstandard normal diffusion. We refer to the associated deterministic equation as a volume-constrained nonlocal diffusion equation. The volume constraint is the nonlocal analogue of a boundary condition necessary to demonstrate that the nonlocal diffusion equation is well-posed and is consistent with the jump process. A critical aspect of the analysis is a variational formulation and a recently developed nonlocal vector calculus. Furthermore, this calculus allows us to pose nonlocal backward and forward Kolmogorov equations, the former equation granting the various moments of the exit-time distribution.

  13. The exit-time problem for a Markov jump process

    Science.gov (United States)

    Burch, N.; D'Elia, M.; Lehoucq, R. B.

    2014-12-01

    The purpose of this paper is to consider the exit-time problem for a finite-range Markov jump process, i.e, the distance the particle can jump is bounded independent of its location. Such jump diffusions are expedient models for anomalous transport exhibiting super-diffusion or nonstandard normal diffusion. We refer to the associated deterministic equation as a volume-constrained nonlocal diffusion equation. The volume constraint is the nonlocal analogue of a boundary condition necessary to demonstrate that the nonlocal diffusion equation is well-posed and is consistent with the jump process. A critical aspect of the analysis is a variational formulation and a recently developed nonlocal vector calculus. This calculus allows us to pose nonlocal backward and forward Kolmogorov equations, the former equation granting the various moments of the exit-time distribution.

  14. Nuclear energy - no thanks. The long way to the exit

    International Nuclear Information System (INIS)

    The anti-nuclear movement is one of the most successful social movements of the recent history of Germany and firmly anchored in huge parts of the population. After a struggle lasting more than forty years it has nearly reached its aims: The exit from nuclear energy and a rethinking in direction of alternative energy concepts. Decisive for the nuclear exit of the Federal government were thereby less the nuclear accidents of Harrisburg (1979), Chernobyl (1986), and Fukushima (2011) but rather the decades-long, stubborn commitment of numerous citizens as well as of citizen's initiatives. ''Nuclear energy - no thanks.'' is the analysis of the citizen's movement from Wyhl until Gorleben. The nonviolent activist and peace researcher Sternstein was there from the beginning and reports about anger and indignation that has been condensed to the social movement with political objectives. Extremely helpful are thereby the methods and strategies of nonviolent actions described by him.

  15. EXIT-constrained BICM-ID Design using Extended Mapping

    OpenAIRE

    Fukawa, Kisho; Ormsub, Soulisak; Tölli, Antti; Anwar, Khoirul; Matsumoto, Tad

    2012-01-01

    This article proposes a novel design framework, EXIT-constrained binary switching algorithm (EBSA), for achieving near Shannon limit performance with single parity check and irregular repetition coded bit interleaved codedmodulation and iterative detection with extended mapping (SI-BICM-ID-EM). EBSA is composed of node degree allocation optimization using linear programming (LP) and labeling optimization based on adaptive binary switching algorithm jointly. This technique achieves exact match...

  16. On asymptotic exit-time control problems lacking coercivity

    OpenAIRE

    Motta, Monica; Sartori, Caterina

    2014-01-01

    International audience The research on a class of asymptotic exit-time problems with a vanishing Lagrangian, begun in [M. Motta and C. Sartori, Nonlinear Differ. Equ. Appl. Springer (2014).] for the compact control case, is extended here to the case of unbounded controls and data, including both coercive and non-coercive problems. We give sufficient conditions to have a well-posed notion of generalized control problem and obtain regularity, characterization and approximation results for th...

  17. Exit Options in Corporate Finance: Liquidity versus Incentives

    OpenAIRE

    Aghion, Philippe; Bolton, Patrick; Tirole, Jean

    2004-01-01

    This paper provides a first study of the optimal design of active monitors' exit options in a problem involving a demand for liquidity and costly monitoring of the issuer. Optimal incentives to monitor the issuer may involve restricting the monitor's right to sell her claims on the firm's cash-flow early. But the monitor will then require a liquidity premium for holding such an illiquid claim. In general, therefore, there will be a trade off between incentives and liquidity. The paper highlig...

  18. Renascent Entrepreneurship : Entrepreneurial Preferences Subsequent to Firm Exit

    OpenAIRE

    STAM, Erik; Audretsch, David B.; Meijaard, Joris

    2006-01-01

    Why should individuals that have exited their firm consider re-entering into entrepreneurship, i.e. become renascent entrepreneurs? According to the logic of economic models of firm dynamics there is no reason to re-enter into entrepreneurship following termination of a previous firm. In contrast, research on nascent entrepreneurship has shown the positive effect of entrepreneurial experience on planning a new firm start. Based on the empirical evidence from a database consisting of ex-entrep...

  19. Exit, Voice and Loyalty: A Reading of an Ongoing Debate

    OpenAIRE

    Horia Moasa

    2012-01-01

    Hirschman's (1970) model of voice, exit and loyalty is of great interest to communication and organization studies, since Hirschman was the first social scientist who introduced voice as a response to discontent in organizations. The model has been utilized, developed and complemented, but rarely criticized. The goal of this article is to endeavor in a two-fold critique based on a literature review of current organization studies. First the model is shown to eliminate from its structure a fun...

  20. THE IMPACT OF HACCP ON COSTS AND PRODUCT EXIT

    OpenAIRE

    Hooker, Neal H.; Nayga, Rodolfo M; Siebert, John W.

    2002-01-01

    Detailed information on firm level food safety costs is reported. Survey data for small and very small meat processors are modeled. Economies of scale in implementing Hazard Analysis Critical Control Point (HACCP) systems are investigated. Results indicate that even after controlling for scale, ver small plants incur higher compliance costs. Diseconomies of scope are assessed using the probability and number of products discontinued due to HACCP. Such "partial exit" is positively related to t...

  1. Exits in the gasoline market: evidence from Austria

    OpenAIRE

    Nikolic, Adriana; Weiss, Christoph

    2013-01-01

    The retail gasoline market is going through a process of restructuring and consolidation in many developed economies. During the past decade, a large number of gasoline stations have been closed down. The present paper aims to investigate this process. One of the key characteristics of the retail gasoline market is that competition is localised, and this spatial dimension of competition has to be taken into account when investigating the (binary) decision of whether or not to exit...

  2. Mitotic exit: Determining the PP2A dephosphorylation program.

    Science.gov (United States)

    Pereira, Gislene; Schiebel, Elmar

    2016-08-29

    In mitotic exit, proteins that were highly phosphorylated are sequentially targeted by the phosphatase PP2A-B55, but what underlies substrate selection is unclear. In this issue, Cundell et al. (2016. J. Cell Biol http://dx.doi.org/10.1083/jcb.201606033) identify the determinants of PP2A-B55's dephosphorylation program, thereby influencing spindle disassembly, nuclear envelope reformation, and cytokinesis. PMID:27551057

  3. Low Income Dynamics: Analyzing poverty exits and entries

    OpenAIRE

    J.-P. ZOYEM

    2002-01-01

    Since 1994, the European Community Household Panel provides information on changes in the French households income and on household situation vis-à-vis the labour market month after month. Using the five available waves, this paper investigates the impact of some family events and changes in the job market situation on poverty exits and entries. The analysis focuses on working age households. Poor households are defined as those with a living standard lower than 60% of the median equivalent i...

  4. Discrete Element Crowd Model for Pedestrian Evacuation Through an Exit

    CERN Document Server

    Lin, Peng; Lo, Siuming

    2016-01-01

    A series of accidents caused by crowd within the last decades evoked a lot of scientific interest in modeling the movement of pedestrian crowds. Based on discrete element method, a granular dynamic model, in which human body is simplified as self-driven sphere, is proposed to simulate the characteristics of crowd flow through an exit. In this model, the repulsive force among people is considered to have an anisotropic feature, and the physical contact force due to body deformation is quantified by the Hertz contact model. The movement of human body is simulated by applying the second Newton's law. The crowd flow through an exit at different desired velocities is studied and simulation results indicated that crowd flow exhibits three distinct states, i.e., smooth state, transition state and phase separation state. In the simulation, clogging phenomenon occurs more easily when the velocity of desired is high and the exit may as a result be totally blocked at a desired velocity of 1.6m/s or above, leading to fas...

  5. Exit, Voice and Loyalty: A Reading of an Ongoing Debate

    Directory of Open Access Journals (Sweden)

    Horia Moasa

    2012-05-01

    Full Text Available Hirschman's (1970 model of voice, exit and loyalty is of great interest to communication and organization studies, since Hirschman was the first social scientist who introduced voice as a response to discontent in organizations. The model has been utilized, developed and complemented, but rarely criticized. The goal of this article is to endeavor in a two-fold critique based on a literature review of current organization studies. First the model is shown to eliminate from its structure a fundamental cognate concept: silence. I willdemonstrate that the two decisions that actors have to make on the verge of organizational deterioration, voice or exit, revolve, in fact, around the concepts of voice and silence, and that these two are so interrelated and intertwined that they presuppose each other.Second, this functionalistic model silences identity issuesthat employees have to deal with when faced with fundamental organizational decisions: to voice discontent or to exit the organization. Moreover, a post-structuralist perspective on employee identity constructionnprocess is presented.

  6. First exit times of harmonically trapped particles: a didactic review

    International Nuclear Information System (INIS)

    We revise the classical problem of characterizing first exit times of a harmonically trapped particle whose motion is described by a one- or multidimensional Ornstein–Uhlenbeck process. We start by recalling the main derivation steps of a propagator using Langevin and Fokker–Planck equations. The mean exit time, the moment-generating function and the survival probability are then expressed through confluent hypergeometric functions and thoroughly analyzed. We also present a rapidly converging series representation of confluent hypergeometric functions that is particularly well suited for numerical computation of eigenvalues and eigenfunctions of the governing Fokker–Planck operator. We discuss several applications of first exit times, such as the detection of time intervals during which motor proteins exert a constant force onto a tracer in optical tweezers single-particle tracking experiments; adhesion bond dissociation under mechanical stress; characterization of active periods of trend-following and mean-reverting strategies in algorithmic trading on stock markets; relation to the distribution of first crossing times of a moving boundary by Brownian motion. Some extensions are described, including diffusion under quadratic double-well potential and anomalous diffusion. (topical review)

  7. Discrete element crowd model for pedestrian evacuation through an exit

    Science.gov (United States)

    Peng, Lin; Jian, Ma; Siuming, Lo

    2016-03-01

    A series of accidents caused by crowds within the last decades evoked a lot of scientific interest in modeling the movement of pedestrian crowds. Based on the discrete element method, a granular dynamic model, in which the human body is simplified as a self-driven sphere, is proposed to simulate the characteristics of crowd flow through an exit. In this model, the repulsive force among people is considered to have an anisotropic feature, and the physical contact force due to body deformation is quantified by the Hertz contact model. The movement of the human body is simulated by applying the second Newton’s law. The crowd flow through an exit at different desired velocities is studied and simulation results indicated that crowd flow exhibits three distinct states, i.e., smooth state, transition state and phase separation state. In the simulation, the clogging phenomenon occurs more easily when the desired velocity is high and the exit may as a result be totally blocked at a desired velocity of 1.6 m/s or above, leading to faster-to-frozen effect. Project supported by the National Natural Science Foundation of China (Grant Nos. 71473207, 51178445, and 71103148), the Research Grant Council, Government of Hong Kong, China (Grant No. CityU119011), and the Fundamental Research Funds for the Central Universities, China (Grant Nos. 2682014CX103 and 2682014RC05).

  8. First exit times of harmonically trapped particles: a didactic review

    Science.gov (United States)

    Grebenkov, Denis S.

    2015-01-01

    We revise the classical problem of characterizing first exit times of a harmonically trapped particle whose motion is described by a one- or multidimensional Ornstein-Uhlenbeck process. We start by recalling the main derivation steps of a propagator using Langevin and Fokker-Planck equations. The mean exit time, the moment-generating function and the survival probability are then expressed through confluent hypergeometric functions and thoroughly analyzed. We also present a rapidly converging series representation of confluent hypergeometric functions that is particularly well suited for numerical computation of eigenvalues and eigenfunctions of the governing Fokker-Planck operator. We discuss several applications of first exit times, such as the detection of time intervals during which motor proteins exert a constant force onto a tracer in optical tweezers single-particle tracking experiments; adhesion bond dissociation under mechanical stress; characterization of active periods of trend-following and mean-reverting strategies in algorithmic trading on stock markets; relation to the distribution of first crossing times of a moving boundary by Brownian motion. Some extensions are described, including diffusion under quadratic double-well potential and anomalous diffusion.

  9. Leaching of polycyclic aromatic hydrocarbons from new and reclaimed asphalt pavements

    OpenAIRE

    Legret, M.; ODIE, L; DEMARE, D; MONERON, P; Jullien, A.

    2005-01-01

    This work presented herein displays the results of a study addressing environmental concerns related to the possible leaching of pollutants from new and reclaimed asphalt pavement. Samples from an experimental site were tested in both static batch tests and columns leaching tests. Selected polycyclic aromatic hydrocarbons (PAHs) were analysed in leachates. The results have allowed us to consider the leaching of pollutants to be rather weak. Concentrations in solutions from batch leaching test...

  10. Leaching of heavy metals and polycyclic aromatic hydrocarbons from reclaimed asphalt pavement

    OpenAIRE

    Legret, M.; ODIE, L; DEMARE, D; Jullien, A.

    2005-01-01

    The work presented herein displays the results of a study addressing environmental concerns related to the possible leaching of pollutants from reclaimed asphalt pavement. Samples from an experimental site were tested in both static batch tests and column leaching tests. Selected heavy metals and polycyclic aromatic hydrocarbons (PAHs) were analysed in leachates. The results have allowed us to consider the leaching of pollutants to be rather weak for most of the parameters studied. Concentrat...

  11. 陕北延河流域土壤多环芳烃分布特征及来源%Distribution and sources of polycyclic aromatic hydrocarbon (PAHs) pollutants in soils of Yanhe River basin,north of Shaanxi province

    Institute of Scientific and Technical Information of China (English)

    李琦; 黄廷林; 尚晓青; 薛科社

    2011-01-01

    On the basis of 16 surface soil samples collected from 4 types of land in the Yanhe River basin,north of Shaanxi province,the concentrations and component characteristics of 16 polycyclic aromatic hydrocarbons(PAHs) which have been being prior controlled by USEPA were analyzed using GC-MS.The results show that the maximum PAHs concentration in all soil samples was 1 795.4 μg/kg with a minimum value of 73.7 μg/kg.For residues of PAHs in the soil,it was characterized by well field soil soil around road soil around the well site agricultural soil.However,the soil pollution with higher residual concentration of PAHs was not serious.The main component of PAHs from soil sample in the study area is mainly formed by two-ring hydrocarbons.In general,the PAHs content in soil ranged as follows: two-ringfour-ringthree-ring five-ringsix-ring.Evaporation or leakage of oil had a significantly cumulative effect on PAHs in the soil.%采集了陕北延河流域4种土地类型区的16个表层土壤样品,采用GC-MS对美国环境保护局(USEPA)优控的l6种多环芳烃(PAHs)进行含量和组分特征的分析.结果表明:陕北延河流域不同类型土壤中PAHs的平均质量分数为73.7~1 795.4μg/kg,PAHs在土壤中的残留特征为井场土壤〉公路周边土壤〉井场周围土壤〉农田土壤,残留水平高的区域处于中等污染水平,部分点位代表区域污染较严重;研究区内PAHs的组分特征是以二环为主的低环组分,PAHs的含量总变化趋势是二环〉四环〉三环〉五环〉六环,石油类挥发或泄漏对采油区土壤中PAHs的累积影响显著.

  12. Life-course health and labour market exit in thirteen European countries : results from SHARELIFE

    OpenAIRE

    Avendano, Mauricio; Mackenbach, Johan

    2010-01-01

    Headlines Health and labour market participation Measuring labour market exits and health Illness over the life-course The impact of illness on labour market exit The role of public health and labour policies Conclusions

  13. Bacterial degradation of monocyclic aromatic amines

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar Arora

    2015-08-01

    Full Text Available Aromatic amines are an important group of industrial chemicals, which are widely used for manufacturing of dyes, pesticides, drugs, pigments, and other industrial products. These compounds have been considered highly toxic to human beings due to their carcinogenic nature. Three groups of aromatic amines have been recognized: monocyclic, polycyclic and heterocyclic aromatic amines. Bacterial degradation of several monocyclic aromatic compounds has been studied in a variety of bacteria, which utilizes monocyclic aromatic amines as their sole source of carbon and energy. Several degradation pathways have been proposed and the related enzymes and genes have also been characterized. Many reviews have been reviewed toxicity of monocyclic aromatic amines; however, there is lack of review on biodegradation of monocyclic aromatic amines. The aim of this review is to summarize bacterial degradation of monocyclic aromatic amines. This review will increase our current understanding of biochemical and molecular basis of bacterial degradation of monocyclic aromatic amines.

  14. Aromatic-Aromatic Interactions in Biological System: Structure Activity Relationships

    Energy Technology Data Exchange (ETDEWEB)

    Rajagopal, Appavu; Deepa, Mohan [Molecular Biophysics Unit, Indian Institute of Sciences-Bangalore, Karnataka (India); Govindaraju, Munisamy [Bio-Spatial Technology Research Unit, Department of Environmental Biotechnology, School of Environmental Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu (India)

    2016-02-26

    While, intramolecular hydrogen bonds have attracted the greatest attention in studies of peptide conformations, the recognition that several other weakly polar interactions may be important determinants of folded structure has been growing. Burley and Petsko provided a comprehensive overview of the importance of weakly polar interactions, in shaping protein structures. The interactions between aromatic rings, which are spatially approximate, have attracted special attention. A survey of the proximal aromatic residue pairs in proteins, allowed Burley and Petsko to suggest that, “phenyl ring centroids are separated by a preferential distance of between 4.5 and 7 Å, and dihedral angles approximately 90° are most common”.

  15. Aromatic-Aromatic Interactions in Biological System: Structure Activity Relationships

    International Nuclear Information System (INIS)

    While, intramolecular hydrogen bonds have attracted the greatest attention in studies of peptide conformations, the recognition that several other weakly polar interactions may be important determinants of folded structure has been growing. Burley and Petsko provided a comprehensive overview of the importance of weakly polar interactions, in shaping protein structures. The interactions between aromatic rings, which are spatially approximate, have attracted special attention. A survey of the proximal aromatic residue pairs in proteins, allowed Burley and Petsko to suggest that, “phenyl ring centroids are separated by a preferential distance of between 4.5 and 7 Å, and dihedral angles approximately 90° are most common”

  16. Aromatic-Aromatic Interactions in Biological System: Structure Activity Relationships

    Directory of Open Access Journals (Sweden)

    Rajagopal Appavu

    2016-03-01

    Full Text Available While, intramolecular hydrogen bonds have attracted the greatest attention in studies of peptide conformations, the recognition that several other weakly polar interactions may be important determinants of folded structure has been growing. Burley and Petsko provided a comprehensive overview of the importance of weakly polar interactions, in shaping protein structures. The interactions between aromatic rings, which are spatially approximate, have attracted special attention. A survey of the proximal aromatic residue pairs in proteins, allowed Burley and Petsko to suggest that, “phenyl ring centroids are separated by a preferential distance of between 4.5 and 7 Å, and dihedral angles approximately 90° are most common”.

  17. The Exit-Voice Tradeoff in the Labor Market: Unionism, Job Tenure, Quits

    OpenAIRE

    Richard B. Freeman

    1980-01-01

    This paper examines the effect of trade unionism on the exit behavior of workers in the context of Hirschman's exit-voice dichotomy. Unionism is expected to reduce quits and permanent separations and raise job tenure by providing a "voice" alternative to exit when workers are dissatisfied with conditions. Empirical evidence supports this contention, showing significantly lower exit for unionists in several large data tapes. It is argued that the grievance system plays a major role in the redu...

  18. Information Pollution

    OpenAIRE

    Noruzi, Alireza

    2000-01-01

    The exponential growth of information resources creates new challenges for end-users. The correct information may be polluted by misinformation, disinformation, propaganda or incorrect information via the Internet and other media. This paper defines 'information pollution' as "the contamination of information by misinformation, disinformation, propaganda and incorrect information." The purpose of this paper is to present the methods of information pollution. It is concluded that it is sometim...

  19. Air Pollution

    OpenAIRE

    Lawther, P. J.

    2014-01-01

    The human costs of air pollution are considerable in Jordan. According to a report published in 2000 by the World Bank under the Mediterranean Environmental Technical Assistance Program (METAP), approximately 600 people die prematurely each year in Jordan because of urban pollution. 50-90% of air pollution in Jordanian towns is caused by road traffic. Readings taken in 2007 by Jordanian researchers showed that levels of black carbon particles in the air were higher in urban areas (caused by v...

  20. 24 CFR 3280.106 - Exit facilities; egress windows and devices.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Exit facilities; egress windows and... § 3280.106 Exit facilities; egress windows and devices. (a) Every room designed expressly for sleeping purposes, unless it has an exit door (see § 3280.105), shall have at least one outside window or...

  1. A combined chemical + enzymatic method to remove selected aromatics from aqueous streams

    International Nuclear Information System (INIS)

    Aromatics are major pollutants found in aqueous environments and in sediments. While there are many chemical and biochemical processes to remove and/or destroy these contaminants, they have to be considered in light of the economics and the time-scales for treatment. We describe our initial work on a hybrid chemical + enzymatic technique to remove aromatics from aqueous stream. The aromatic is first converted to the corresponding phenol through classical Fenton type chemistry involving catalysis by Fe(II). The phenol is subsequently polymerized through an enzymatic mechanism, using horseradish peroxidase as the oxidative enzyme. The polymer is insoluble in water and can be easily recovered. In addition, such phenolic polymers are useful products with varied applications in coatings and resin technologies. Thus, the pollutants can be eventually converted to useful products

  2. Advances towards aromatic oligoamide foldamers

    DEFF Research Database (Denmark)

    Hjelmgaard, Thomas; Plesner, Malene; Dissing, Mette Marie; Andersen, Jeanette Marker; Frydenvang, Karla Andrea; Nielsen, John

    2014-01-01

    We have efficiently synthesized 36 arylopeptoid dimers with ortho-, meta-, and para-substituted aromatic backbones and tert-butyl or phenyl side chains. The dimers were synthesized by using a "submonomer method" on solid phase, by applying a simplified common set of reaction conditions. X......-ray crystallographic analysis of two of these dimers disclosed that the tert-butyl side chain invokes a cis amide conformation with a comparatively more closely packed structure of the surrounding aromatic backbone while the phenyl side chain results in a trans amide conformation with a more open, extended structure...... conformation with a more open, extended structure of the surrounding aromatic backbone. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim....

  3. Environmental exposure to carcinogenic polycyclic aromatic hydrocarbons – the interpretation of cytogenetic analysis by FISH

    Czech Academy of Sciences Publication Activity Database

    Šrám, Radim; Beskid, Olena; Rössnerová, Andrea; Rössner st., Pavel; Lněničková, Zdena; Milcová, Alena; Solansky, I.; Binková, Blanka

    2007-01-01

    Roč. 172, - (2007), s. 12-20. ISSN 0378-4274 R&D Projects: GA MŽP SL/5/160/05 Institutional research plan: CEZ:AV0Z50390512 Keywords : environmental pollution * carcinogenic polycyclic aromatic hydrocarbons * cytogenetic analysis Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 2.826, year: 2007

  4. Effect of three polycyclic aromatic hydrocarbons on nodulation of Rhizobium tropici CIAT 899 on Phaseolus vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Paredes, Y.; Ferrera-Cerrato, R.; Alarcon, A.

    2009-07-01

    Polycyclic aromatic hydrocarbons (PAH) are ubiquitous organic pollutants that are considered toxic and carcinogenic compounds to living organisms. There us scarce information about the effect of PAH on symbiotic systems such as Azolla-Anabaena, arbuscular mycorrhizal fungi-plants, or legume-rhizobia. (Author)

  5. Effect of three polycyclic aromatic hydrocarbons on nodulation of Rhizobium tropici CIAT 899 on Phaseolus vulgaris

    International Nuclear Information System (INIS)

    Polycyclic aromatic hydrocarbons (PAH) are ubiquitous organic pollutants that are considered toxic and carcinogenic compounds to living organisms. There us scarce information about the effect of PAH on symbiotic systems such as Azolla-Anabaena, arbuscular mycorrhizal fungi-plants, or legume-rhizobia. (Author)

  6. Polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in particulates emitted by motorcycles

    International Nuclear Information System (INIS)

    We determined eleven PAHs and four NPAHs in particulates and regulated pollutants (CO, CO2, HC, NOx, PM) exhausted from motorcycles to figure out the characteristics of motorcycle exhausts. Fluoranthene and pyrene accounted for more than 50% of the total detected PAHs. Among four detected NPAHs, 6-nitrochrysene and 7-nitrobenz[a]anthracene were the predominant NPAHs and were highly correlated relationship with their parent PAHs (R = 0.93 and 0.97, respectively). The PM and HC emissions tended to be close to the PAH emissions. NOx and NPAHs were negatively correlated. Despite their small engine size, motorcycles emitted much more PM and PAHs, showed stronger PAH-related carcinogenicity and indirect-acting mutagenicity, but weaker NPAH-related direct-acting mutagenic potency than automobiles. This is the first study to analyze both PAHs and NPAHs emitted by motorcycles, which could provide useful information to design the emission regulations and standards for motorcycles such as PM. -- Highlights: ► We characterized PAHs and NPAHs distribution in motorcycle exhausts. ► NPAHs concentrations were about three orders of magnitude lower than those of PAHs. ► We found larger amounts of PM and PAHs in exhaust of motorcycles than of automobiles. ► Motorcycles showed stronger PAH-related toxicity than automobiles. ► Motorcycles showed weaker NPAH-related direct-acting mutagenicity than automobiles. -- Control polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbon in particulates emitted by motorcycles due to their toxic potency

  7. Activated carbon adsorption-advanced electro-oxidative regeneration for the treatment of biorefractory organic pollutants

    Institute of Scientific and Technical Information of China (English)

    ZHOU Minghua; DAI Qizhou; LEI Lecheng; WANG Dahui

    2005-01-01

    The wastewater containing toxic and biorefractory pollutants such as aromatic compounds cannot be treated by conventional action due to their toxicity and structure stability, which has been one of the key technical difficulties in wastewater treatment in China.

  8. Air Pollution.

    Science.gov (United States)

    Air quality is affected by many types of pollutants that are emitted from various sources, including stationary and mobile. These sources release both criteria and hazardous air pollutants, which cause health effects, ecological harm, and material damage. They are generally categ...

  9. Quantitative research on exit barrier in construction enterprise with different ownership

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-dong; XIAO Hou-zhong; ZHANG Zhi-hui; WANG Dan-song

    2006-01-01

    "Exit barrier" means the obstacle keeping enterprises from competing even though their profits may be negative. This paper presents quantitative research on the exit barrier's effect on the Chinese construction industry using questionnaire investigation. The exit barrier was classified into six categories, and then the categories were ranked and analyzed according to the respondents from the state-owned enterprises (SOEs) and non stateowned enterprises (NSOEs), respectively. The main obstacles related to the exit barrier in SOEs and NSOEs were revealed. Finally, suggestions were provided to diminish the exit barrier effect on the construction industry.

  10. Contamination of Runoff Water at Gdańsk Airport (Poland) by Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs)

    OpenAIRE

    Jacek Namieśnik; Anna Maria Sulej; Żaneta Polkowska

    2011-01-01

    Airport runoff can contain high concentrations of various pollutants, in particular polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), the environmental levels of which have to be monitored. Airport runoff water samples, collected at the Gdańsk-Rębiechowo Airport from 2008 to 2009, were analysed for PAHs and PCBs by gas chromatography. The aromatic fractions were separated by liquid-liquid extraction and analysed by GC/MS. Total PAH concentrations were 295–6,758 ng/...

  11. Survey of Recent Innovations in Aromatic Rice

    OpenAIRE

    Napasintuwong, Orachos

    2012-01-01

    This paper provides situations of aromatic rice demand, and international standards. The history and recent developments of traditional and evolved aromatic rice varieties, namely Basmati rice and Jasmine rice, are reviewed. The emerging aromatic rice innovations from developed countries such as the U.S. and other Asian countries generate a threat to these traditional aromatic rice producers such as India, Pakistan, and Thailand. Under WTO Trade Related Aspects of Intellectual Property Rights...

  12. Trust in triads: effects of exit, control, and learning

    OpenAIRE

    Buskens, Vincent

    2003-01-01

    This paper provides theoretical background for some effects of social networks on trust. We study the implications of a model with rational actors in two settings with three actors. In the first setting, there are two trustees who are involved in transactions with one truster implying that the truster has an exit option. In the second setting, two trusters play with one trustee, which gives the trusters options for voice, i.e., complaining and informing each other about the trustee’s behavior...

  13. Do specialists exit the firm outsourcing its R&D?

    DEFF Research Database (Denmark)

    Wang, Wenjing

    Do specialists exit the firm increasingly outsourcing its research and development (R&D) work? Although this question is critical in understanding how R&D outsourcing links to innovation performance, the answer is not yet clear. This paper proposes that the optimal level of firm's internal...... employment of R&D specialists decreases with the deepening of R&D outsourcing but increases with the broadening of R&D outsourcing. These relations can be inferred from previous empirical studies as well as our theoretical analysis, and are supported by the empirical evidence from estimations of correlated...

  14. Improved social force model based on exit selection for microscopic pedestrian simulation in subway station

    Institute of Scientific and Technical Information of China (English)

    郑勋; 李海鹰; 孟令云; 许心越; 陈旭

    2015-01-01

    An improved social force model based on exit selection is proposed to simulate pedestrians’ microscopic behaviors in subway station. The modification lies in considering three factors of spatial distance, occupant density and exit width. In addition, the problem of pedestrians selecting exit frequently is solved as follows: not changing to other exits in the affected area of one exit, using the probability of remaining preceding exit and invoking function of exit selection after several simulation steps. Pedestrians in subway station have some special characteristics, such as explicit destinations, different familiarities with subway station. Finally, Beijing Zoo Subway Station is taken as an example and the feasibility of the model results is verified through the comparison of the actual data and simulation data. The simulation results show that the improved model can depict the microscopic behaviors of pedestrians in subway station.

  15. Polycyclic aromatic hydrocarbons residues in sandstorm depositions in Beijing, China.

    Science.gov (United States)

    Fu, S; Li, K; Xia, X J; Xu, X B

    2009-02-01

    This study was conducted to determine the concentration of 16 polycyclic aromatic hydrocarbons (PAHs) in sandstorm depositions in Beijing, China. The PAH concentrations in 13 samples collected in Beijing ranged from 0.18 to 3.52 microg g(-1). Analysis of the sources of contamination revealed that the PAHs were derived from a coal combustion source, although various effects of traffic emissions were also observed. Furthermore, the PAH levels in Beijing tended to be higher in the southeast. Finally, the nemerow composite index revealed that the degree of pollution in the sandstorm depositions varied widely among sampling sites. PMID:18773130

  16. Polycyclic aromatic hydrocarbons residues in sandstorm depositions in Beijing, China

    Energy Technology Data Exchange (ETDEWEB)

    Fu, S.; Li, K.; Xia, X.J.; Xu, X.B. [Chinese Academy of Sciences, Beijing (China)

    2009-02-15

    This study was conducted to determine the concentration of 16 polycyclic aromatic hydrocarbons (PAHs) in sandstorm depositions in Beijing, China. The PAH concentrations in 13 samples collected in Beijing ranged from 0.18 to 3.52 {mu} g g{sup -1}. Analysis of the sources of contamination revealed that the PAHs were derived from a coal combustion source, although various effects of traffic emissions were also observed. Furthermore, the PAH levels in Beijing tended to be higher in the southeast. Finally, the Nemerow composite index revealed that the degree of pollution in the sandstorm depositions varied widely among sampling sites.

  17. Capillary and microchip electrophoretic analysis of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Ferey, Ludivine; Delaunay, Nathalie

    2015-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants which can reach the environment and food in different ways. Because of their high toxicity, two international regulatory institutions, the US Environmental Protection Agency and the European Food Safety Authority, have classified PAHs as priority pollutants, generating an important demand for the detection and identification of PAHs. Thus, sensitive, fast, and cheap methods for the analysis of PAHs in environmental and food samples are urgently needed. Within this context, electrophoresis, in capillary or microchip format, displays attractive features. This review presents and critically discusses the published literature on the different approaches to capillary and microchip electrophoresis analysis of PAHs. PMID:25542576

  18. Degradation of aromatic amines in textile-dyeing sludge by combining the ultrasound technique with potassium permanganate treatment.

    Science.gov (United States)

    Liang, Jieying; Ning, Xun-An; An, Taicheng; Sun, Jian; Zhang, Yaping; Wang, Yujie

    2016-08-15

    This paper reports, for the first time, a combined technique of ultrasound (US) with KMnO4 degradation of aromatic amines in a textile-dyeing sludge. The reaction mechanisms and the degradation kinetics of aromatic amines at various operating parameters (KMnO4 dosage, US power density and pH) were systematically examined by the combined system of US-KMnO4. The results indicated that there was a synergistic effect between US and KMnO4, as US greatly enhanced KMnO4 in the degradation of aromatic amines and exhibited apparent sludge disintegration and separated pollutants from the sludge. In addition to accelerating the Mn(VII) reaction with pollutants in the filtrate, US also caused Mn(VII) to enter the porous sludge and sufficiently facilitated the reaction of the strongly absorbed aromatic amines. The combined treatment of US-KMnO4 was effective in the degradation of aromatic amines in textile-dyeing sludge. On average, 58.7% of monocyclic anilines, 88.3% of other forms of aromatic amines, and 24.0% of TOC were removed under the optimal operating conditions of a KMnO4 dosage of 12mM, an US power density of 1.80W/cm(3) and pH 5. The present study proposed US-KMnO4 treatment as a practical method for the disposal of aromatic amines in textile-dyeing sludge. PMID:27107230

  19. Environmental Pollution

    International Nuclear Information System (INIS)

    This book tells US that what nature is, which gives descriptions of the world of living things like the role of plant, order of the vegetable kingdom, the world of plant, destruction of the natural world, and the world of bugs, nature and human with man's survive and change of nature, environment and human, and in creasing population and environment, philosophy of conservation of nature on meaning, destroy and management, and direction, air pollution spot, water pollution, soil pollution conservation of nature and industry case of foreign country and view of environment and environmental assimilating capacity.

  20. Steam exit flow design for aft cavities of an airfoil

    Science.gov (United States)

    Storey, James Michael; Tesh, Stephen William

    2002-01-01

    Turbine stator vane segments have inner and outer walls with vanes extending therebetween. The inner and outer walls have impingement plates. Steam flowing into the outer wall passes through the impingement plate for impingement cooling of the outer wall surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. A skirt or flange structure is provided for shielding the steam cooling impingement holes adjacent the inner wall aerofoil fillet region of the nozzle from the steam flow exiting the aft nozzle cavities. Moreover, the gap between the flash rib boss and the cavity insert is controlled to minimize the flow of post impingement cooling media therebetween. This substantially confines outflow to that exiting via the return channels, thus furthermore minimizing flow in the vicinity of the aerofoil fillet region that may adversely affect impingement cooling thereof.

  1. Exit flow measurements of a centrifugal pump impeller

    International Nuclear Information System (INIS)

    Discharge flows from a centrifugal pump impeller with a specific speed of 150 [rpm, m3/min, m] were experimentally investigated. A large axisymmetric collector instead of a volute casing was installed to obtain circumferentially uniform flow, i.e. without interaction of the impeller and the volute. The unsteady flow was measured at the impeller exit and vaneless diffuser using a hot film probe and a pressure transducer. The flow at impeller exit showed pronounced jet-wake flow patterns. The wake, which was on the suction/hub side at high flow rate, became enlarged pitchwisely on both the hub and the shroud side as the flow rate decreases. The pitchwise non-uniformity of the flow rapidly decreased along the downstream and the non-uniformity almost disappeared at radius ratio of 1.18 for medium flow rate. The mean vaneless diffuser flow was reasonably predicted using a one dimensional analysis when an empirical constant was used to specify the skin friction coefficient. The data can be used for a centrifugal pump impeller design and validation of CFD codes and flow modeling

  2. Light Pollution

    Science.gov (United States)

    Riegel, Kurt W.

    1973-01-01

    Outdoor lighting is light pollution which handicaps certain astronomical programs. Protective measures must be adopted by the government to aid observational astronomy without sacrificing legitimate outdoor lighting needs. (PS)

  3. Air pollution

    International Nuclear Information System (INIS)

    Australian cites experience a number of current and emerging air pollution problems. Concentrations of traditional primary pollutants such as CO, lead and dust have fallen in recent years as a consequence of air pollutant control measures, and the widespread introduction of lead-free petrol. However, recommended guidelines for ozone, the principal component of photochemical smog, are regularly exceeded in major capital cities in the summer months. In addition, it is predicted that extensive urban expansion will lead to much greater dependence on the motor vehicle as the primary means of transportation. Effects of air pollution are felt at a variety of scales. Traditionally, concerns about gaseous and particulate emissions from industrial and vehicular sources were focused on local impacts due to exposure to toxic species such as CO and lead. As noted above, concentrations of these pollutants have been reduced by a variety of control measures. Pollutants which have effects at a regional scale, such as photochemically-produced ozone, and acidic gases and particles have proved more difficult to reduce. In general, these pollutants arc not the result of direct emissions to atmosphere, but result from complex secondary processes driven by photochemical reactions of species such as NO2 and aldehydes. In addition, global effects of gaseous and particulate emissions to the atmosphere have received significant recent attention, concentrations of atmospheric CO2 with predicted impacts on global climate, and ozone depletion due to anthropogenic emissions of chlorine-containing chemicals are the two major examples. Combustion processes from petrol- and diesel-fuelled vehicles, make major contributions to air pollution, and the magnitude of this contribution is discussed in this article

  4. [Polycyclic aromatic hydrocarbons exposure and birth defects].

    Science.gov (United States)

    Lin, S S; Huang, Y; Wang, C Y; Ren, A G

    2016-06-01

    Birth defects are one of the most common adverse birth outcomes, which create a heavy economic burden to the country, society and family. And they are also one of the biggest problems facing public health today. Polycyclic aromatic hydrocarbons (PAHs) are a group of toxic pollutants existing in the environment widely, resulting from incomplete organic matter combustion, and can be taken into the body through various ways including the digestive tract, respiratory tract and so on. Recent researches suggest that the exposure of PAHs may be associated with various birth defects, while the special mechanism isn't very clear. This paper is a review of the relationship between PAHs and birth defects from the aspects of epidemiological data, experimental evidence on animals, which indicates that exposure of PAHs during pregnancy may be associated with birth defects including congenital heart defects, neural tube defects and cleft lip/plate. Furthermore, we explored the possible mechanism, including oxidative stress, oxidative damage and the changes of signal transduction pathway in order to provide some recommendations and suggestions on the future work. PMID:27256742

  5. Ground Pollution Science

    International Nuclear Information System (INIS)

    This book deals with ground pollution science and soil science, classification of soil and fundamentals, ground pollution and human, ground pollution and organic matter, ground pollution and city environment, environmental problems of the earth and ground pollution, soil pollution and development of geological features of the ground, ground pollution and landfill of waste, case of measurement of ground pollution.

  6. Risk assessment of metals and organic pollutants for herbivorous and carnivorous small mammal food chains in a polluted floodplain (Biesbosch, The Netherlands)

    NARCIS (Netherlands)

    Hamers, T.H.M.; Berg, van den J.H.J.; Gestel, van C.A.M.; Schooten, van F.J.; Murk, A.J.

    2006-01-01

    A risk assessment was made for a carnivorous and a herbivorous food chain in a heavily polluted natural estuary (Biesbosch), by determining the most critical pollutants and the food chain most at risk. Exposure of food chains to metals, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated bi

  7. Nucleophilic fluorination of aromatic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Satyamurthy, Nagichettiar; Barrio, Jorge R

    2014-03-18

    Iodylbenzene derivatives substituted with electron donating as well as electron withdrawing groups on the aromatic ring are used as precursors in aromatic nucleophilic substitution reactions. The iodyl group (IO.sub.2) is regiospecifically substituted by nucleophilic fluoride to provide the corresponding fluoroaryl derivatives. No-carrier-added [F-18]fluoride ion derived from anhydrous [F-18](F/Kryptofix, [F-18]CsF or a quaternary ammonium fluoride (e.g., Me.sub.4NF, Et.sub.4NF, n-Bu.sub.4NF, (PhCH.sub.2).sub.4NF) exclusively substitutes the iodyl moiety in these derivatives and provides high specific activity F-18 labeled fluoroaryl analogs. Iodyl derivatives of a benzothiazole analog and 6-iodyl-L-dopa derivatives have been synthesized as precursors and have been used in the preparation of no-carrier-added [F-18]fluorobenzothiazole as well as 6-[F-18]fluoro-L-dopa.

  8. Oil and detergent pollution on coastal areas of Dardanelles in 1996-1997

    OpenAIRE

    Güven, Kasim Cemal; Ilgar, Rüstü

    2002-01-01

    Abstract The oil and detergent pollution was determined in coastal waters and sediments in Dardanelles at entrance, Gelibolu and Lapseki; at exit, Çanakkale. The max. level of oil pollution in sea water was 154.76 µg/L at the entrance and 76.30 µ/L at the exit in 1996; 429.54 µg/L and 539.10 µg/L respectively in 1997. In sediments 51.13 µg/g at the entrance and 338.76 µg/L at the exit in 1996 and 369.56 µg/L and 339.56 in 1997. In detergent pollution the max.level was 50.51 µg/L at the ...

  9. TomoTherapy MLC verification using exit detector data

    International Nuclear Information System (INIS)

    Purpose: Treatment delivery verification (DV) is important in the field of intensity modulated radiation therapy (IMRT). While IMRT and image guided radiation therapy (IGRT), allow us to create more conformal plans and enables the use of tighter margins, an erroneously executed plan can have detrimental effects on the treatment outcome. The purpose of this study is to develop a DV technique to verify TomoTherapy's multileaf collimator (MLC) using the onboard mega-voltage CT detectors. Methods: The proposed DV method uses temporal changes in the MVCT detector signal to predict actual leaf open times delivered on the treatment machine. Penumbra and scattered radiation effects may produce confounding results when determining leaf open times from the raw detector data. To reduce the impact of the effects, an iterative, Richardson-Lucy (R-L) deconvolution algorithm is applied. Optical sensors installed on each MLC leaf are used to verify the accuracy of the DV technique. The robustness of the DV technique is examined by introducing different attenuation materials in the beam. Additionally, the DV technique has been used to investigate several clinical plans which failed to pass delivery quality assurance (DQA) and was successful in identifying MLC timing discrepancies as the root cause. Results: The leaf open time extracted from the exit detector showed good agreement with the optical sensors under a variety of conditions. Detector-measured leaf open times agreed with optical sensor data to within 0.2 ms, and 99% of the results agreed within 8.5 ms. These results changed little when attenuation was added in the beam. For the clinical plans failing DQA, the dose calculated from reconstructed leaf open times played an instrumental role in discovering the root-cause of the problem. Throughout the retrospective study, it is found that the reconstructed dose always agrees with measured doses to within 1%. Conclusions: The exit detectors in the TomoTherapy treatment systems

  10. Analysis of heterocyclic aromatic amines.

    Science.gov (United States)

    Murkovic, M

    2007-09-01

    Heterocyclic aromatic amines are formed in protein and amino acid-rich foods at temperatures above 150 degrees C. Of more than twenty heterocyclic aromatic amines identified ten have been shown to have carcinogenic potential. As nutritional hazards, their reliable determination in prepared food, their uptake and elimination in living organisms, including humans, and assessment of associated risks are important food-safety issues. The concentration in foods is normally in the low ng g(-1) range, which poses a challenge to the analytical chemist. Because of the complex nature of food matrixes, clean-up and enrichment of the extracts are also complex, usually involving both cation-exchange (propylsulfonic acid silica gel, PRS) and reversed-phase purification. The application of novel solid-phase extraction cartridges with a wettable apolar phase combined with cation-exchange characteristics simplified this process--both the polar and apolar heterocyclic aromatic amines were recovered in one fraction. Copper phthalocyanine trisulfonate bonded to cotton ("blue cotton") or rayon, and molecular imprinted polymers have also been successfully used for one-step sample clean-up. For analysis of the heterocyclic aromatic amines, liquid chromatography with base-deactivated reversed-phase columns has been used, and, recently, semi-micro and capillary columns have been introduced. The photometric, fluorimetric, or electrochemical detectors used previously have been replaced by mass spectrometers. Increased specificity and sub-ppb sensitivities have been achieved by the use of the selected-reaction-monitoring mode of detection of advanced MS instrumentation, for example the triple quadrupole and Q-TOF instrument combination. Gas chromatography, also with mass-selective detection, has been used for specific applications; the extra derivatization step needed for volatilization has been balanced by the higher chromatographic resolution. PMID:17546447

  11. Air pollution measurements in traffic tunnels.

    OpenAIRE

    De Fré, R; Bruynseraede, P; Kretzschmar, J G

    1994-01-01

    Air pollution measurements during April 1991 are reported from the Craeybeckx highway tunnel in Antwerp, Belgium. The tunnel was used daily by an average of 45,000 vehicles, of which 60% were gasoline fueled passenger cars, 20% diesel cars, and 20% trucks. Of the gasoline cars, only 3% had three-way catalysts. Tunnel air concentrations of nitrogen oxides, sulphur dioxide, carbon dioxide, carbon monoxide, nonmethane hydrocarbons, volatile organic compounds, polycyclic aromatic hydrocarbons, an...

  12. Deuterated polycyclic aromatic hydrocarbons: Revisited

    CERN Document Server

    Doney, Kirstin D; Mori, Tamami; Onaka, Takashi; Tielens, A G G M

    2016-01-01

    The amount of deuterium locked up in polycyclic aromatic hydrocarbons (PAHs) has to date been an uncertain value. We present a near-infrared (NIR) spectroscopic survey of HII regions in the Milky Way, Large Magellanic Cloud (LMC), and Small Magellanic Cloud (SMC) obtained with AKARI, which aims to search for features indicative of deuterated PAHs (PAD or Dn-PAH) to better constrain the D/H ratio of PAHs. Fifty-three HII regions were observed in the NIR (2.5-5 {\\mu}m), using the Infrared Camera (IRC) on board the AKARI satellite. Through comparison of the observed spectra with a theoretical model of deuterated PAH vibrational modes, the aromatic and (a)symmetric aliphatic C-D stretch modes were identified. We see emission features between 4.4-4.8 {\\mu}m, which could be unambiguously attributed to deuterated PAHs in only six of the observed sources, all of which are located in the Milky Way. In all cases, the aromatic C-D stretching feature is weaker than the aliphatic C-D stretching feature, and, in the case o...

  13. The direct aromatization of methane

    Energy Technology Data Exchange (ETDEWEB)

    Marcelin, G.; Oukaci, R.; Migone, R.A.; Kazi, A.M. [Altamira Instruments, Pittsburgh, PA (United States)

    1995-12-31

    The thermal decomposition of methane shows significant potential as a process for the production of higher unsaturated and aromatic hydrocarbons when the extent of the reaction is limited. Thermodynamic calculations have shown that when the reaction is limited to the formation of C{sub 2} to C{sub 10} products, yields of aromatics can exceed 40% at temperatures of 1200{degrees}C. Preliminary experiments have shown that when the reaction is limited to the formation of C{sub 2} to C{sub 10} products, yields of aromatics can exceed 40% at temperatures of 1200{degrees}C. Preliminary experiments have shown that cooling the product and reacting gases as the reaction proceeds can significantly reduce or eliminate the formation of solid carbon and heavier (C{sub 10+}) materials. Much work remains to be done in optimizing the quenching process and this is one of the goals of this program. Means to lower the temperature of the reaction are being studied as this result in a more feasible commercial process due to savings realized in energy and material of construction costs. The use of free-radical generators and catalysts will be investigated as a means of lowering the reaction temperature thus allowing faster quenching. It is highly likely that such studies will lead to a successful direct methane to higher hydrocarbon process.

  14. Petroleum pollution and mutation in mangroves

    International Nuclear Information System (INIS)

    Chlorophyll-deficiency has often been used as a sensitive genetic end-point in plant mutation research. The frequency of trees heterozygous for nuclear chlorophyll-deficient mutations was determined for mangrove populations growing along the southwest coast of Puerto Rico. The frequency of heterozygotes was strongly correlated with the concentration of polycyclic aromatic hydrocarbons in the underlying sediment and with both acute and chronic petroleum pollution. Although epidemiological studies can seldom prove causation, a strong correlation is certainly compatible with a cause-effect relationship. Our results suggest that the biota of oil-polluted habitats may be experiencing increased mutation. (Author)

  15. FISH CANCER DEVELOPED BY ENVIRONMENTAL POLLUTANTS

    Directory of Open Access Journals (Sweden)

    Madhuri S.

    2012-10-01

    Full Text Available The pollution of rivers and streams with chemical contaminants has become one of the most critical environmental problems. Fish living in a polluted water reservoir use the contaminated water to rinse their gills; this results in the deposition of polycyclic aromatic hydrocarbons (PAHs in the fish body. Contamination of foodstuffs by heavy metals such as arsenic, cadmium, chromium, nickel and lead has poses a potential carcinogenic threat to humans. Arsenic and cadmium appear to be the most harmful to the fish. Several cancers in fish appear to be the result of exposure to different environmental pollutants/chemicals. High frequencies of liver and skin cancers in brown bullheads are associated with high concentrations of PAHs and some metals in the environmental sediments. Taking these facts in view, the present article gives the emphasis on the fish cancer caused by various environmental pollutants, suggesting that fish species are truly suffer from different cancers/tumours.

  16. Water pollution treatability: a molecular engineering approach

    Energy Technology Data Exchange (ETDEWEB)

    Strier, M.P.

    1980-01-01

    Estimated effluent limits for priority nonpesticide organic pollutants, such as phenol and carbon tetrachloride, were developed from the physical-chemical properties (molecular weight, boiling point, and water solubility) and the biochemical oxidizability of these pollutants. These properties were used to develop a separate treatment model (or system) for each pollutant from the following unit treatment processes: steam- or air-stripping; oil/water separation; filtration-diatomaceous or dual media; biochemical oxidation; and activated-carbon adsorption. Pollutants with highest treatability (1.0 jg/1. in the effluent) were generally high molecular weight polycyclic aromatic hydrocarbons and chlorohydrocarbons, e.g., chrysene and benzo(a) pyrene; those with the lowest treatability (100-1000 jg/1. in the effluent) were generally low molecular weight, water-soluble compounds, e.g., acrylo nitrile and vinyl chloride. Solubilities were directly related to the estimated theoretical effluent limitations; partition coefficients and bioconcentration factors were inversely related.

  17. Biodegradation of Various Aromatic Compounds by Enriched Bacterial Cultures: Part A-Monocyclic and Polycyclic Aromatic Hydrocarbons.

    Science.gov (United States)

    Oberoi, Akashdeep Singh; Philip, Ligy; Bhallamudi, S Murty

    2015-08-01

    Present study focused on the screening of bacterial consortium for biodegradation of monocyclic aromatic hydrocarbon (MAH) and polycyclic aromatic hydrocarbons (PAHs). Target compounds in the present study were naphthalene, acenaphthene, phenanthrene (PAHs), and benzene (MAH). Microbial consortia enriched with the above target compounds were used in screening experiments. Naphthalene-enriched consortium was found to be the most efficient consortium, based on its substrate degradation rate and its ability to degrade other aromatic pollutants with significantly high efficiency. Substrate degradation rate with naphthalene-enriched culture followed the order benzene > naphthalene > acenaphthene > phenanthrene. Chryseobacterium and Rhodobacter were discerned as the predominant species in naphthalene-enriched culture. They are closely associated to the type strain Chryseobacterium arthrosphaerae and Rhodobacter maris, respectively. Single substrate biodegradation studies with naphthalene (PAH) and benzene (MAH) were carried out using naphthalene-enriched microbial consortium (NAPH). Phenol and 2-hydroxybenzaldehyde were identified as the predominant intermediates during benzene and naphthalene degradation, respectively. Biodegradation of toluene, ethyl benzene, xylene, phenol, and indole by NAPH was also investigated. Monod inhibition model was able to simulate biodegradation kinetics for benzene, whereas multiple substrate biodegradation model was able to simulate biodegradation kinetics for naphthalene. PMID:26054614

  18. High-Flow Jet Exit Rig Designed and Fabricated

    Science.gov (United States)

    Buehrle, Robert J.; Trimarchi, Paul A.

    2003-01-01

    The High-Flow Jet Exit Rig at the NASA Glenn Research Center is designed to test single flow jet nozzles and to measure the appropriate thrust and noise levels. The rig has been designed for the maximum hot condition of 16 lbm/sec of combustion air at 1960 R (maximum) and to produce a maximum thrust of 2000 lb. It was designed for cold flow of 29.1 lbm/sec of air at 530 R. In addition, it can test dual-flow nozzles (nozzles with bypass flow in addition to core flow) with independent control of each flow. The High- Flow Jet Exit Rig was successfully fabricated in late 2001 and is being readied for checkout tests. The rig will be installed in Glenn's Aeroacoustic Propulsion Laboratory. The High-Flow Jet Exit Rig consists of the following major components: a single component force balance, the natural-gas-fueled J-79 combustor assembly, the plenum and manifold assembly, an acoustic/instrumentation/seeding (A/I/S) section, a table, and the research nozzles. The rig will be unique in that it is designed to operate uncooled. The structure survives the 1960 R test condition because it uses carefully selected high temperature alloy materials such as Hastelloy-X. The lower plenum assembly was designed to operate at pressures to 450 psig at 1960 R, in accordance with the ASME B31.3 piping code. The natural gas-fueled combustor fires directly into the lower manifold. The hot air is directed through eight 1-1/2-in. supply pipes that supply the upper plenum. The flow is conditioned in the upper plenum prior to flowing to the research nozzle. The 1-1/2-in. supply lines are arranged in a U-shaped design to provide for a flexible piping system. The combustor assembly checkout was successfully conducted in Glenn's Engine Component Research Laboratory in the spring of 2001. The combustor is a low-smoke version of the J79 combustor used to power the F4 Phantom military aircraft. The natural gas-fueled combustor demonstrated high-efficiency combustion over a wide range of operating

  19. Destruction and Reallocation of Skills Following Large Company Exit

    DEFF Research Database (Denmark)

    Holm, Jacob Rubæk; Østergaard, Christian Richter; Olesen, Thomas Roslyng

    question then becomes: under which conditions are the redundant workers and their skills reallocated to productive use elsewhere in the regional economy and when do the workers find a job where their specific skills are less valuable to the new employer and the worker must start over acquiring new skills......, that is, skill destruction. This study is based on the closure of four shipyards in Denmark from 1987-2000. The analysis is based on detailed longitudinal micro data from a matched employer-employee dataset that allow us to follow the mobility of the laid-off employees in great detail. The analysis......What happens to redundant skills and workers when a large company closes down in a region? The knowledge embodied in firms is lost when firms exit. However, the skills, competences and knowledge embodied in the displaced employees are suddenly released and can become channels of knowledge transfer...

  20. Destruction and Reallocation of Skills Following Large Company Exit

    DEFF Research Database (Denmark)

    Holm, Jacob Rubæk; Østergaard, Christian Richter; Roslyng Olesen, Thomas

    for other firms that hire them. This process can be very disruptive. For instance, when a large, old and well-renowned company closes down displacing thousands of workers over a short period of time, then it may be a shock to the regional economy and lead to unemployment and skill destruction. The......What happens to redundant skills and workers when a large company closes down in a region? The knowledge embodied in firms is lost when firms exit. However, the skills, competences and knowledge embodied in the displaced employees are suddenly released and can become channels of knowledge transfer...... question then becomes: under which conditions are the redundant workers and their skills reallocated to productive use elsewhere in the regional economy and when do the workers find a job where their specific skills are less valuable to the new employer and the worker must start over acquiring new skills...

  1. Real-time multi-function entry / exit management system

    International Nuclear Information System (INIS)

    In order to prevent radiation accident and its expansion, more integrated management system is required to safety management for radiation workers in the nuclear facilities. Therefore, JAEA (Japan Atomic Energy Agency) and HAM (Hitachi Aloka Medical, Ltd) have developed innovative real-time multi-function entry/exit management system which managed worker's exposed dose and position under the joint developed patent. This system is sharing worker's data among workers and server manager who is inside of or outside of building, such as worker's positing, health condition and exposed dose. It consists of mobile equipments, receivers, LAN, and servers system. This report summarizes the system to be installed in the JMTR. (author)

  2. Moral considerations in non-EXIT airway management.

    Science.gov (United States)

    Walker, Paul

    2016-02-01

    The case report "Management of the critical airway when an EXIT procedure is not an option" has important moral decision-making implications. If intubation was not quickly successful, then significant hypoxic brain injury may have resulted. A full discussion of the moral implications in cases such as this, prior to delivery, is important - both to the family and to the clinicians involved. Our contemporary era is characterised by a pronounced disparity of values and belief systems. An active process for moral decision-making based upon dialogic consensus, is seen as more appropriate than contemplation of ethical frameworks alone. This is increasingly important as the armamentarium of life-sustaining technology available to clinicians steadily increases. PMID:26706315

  3. Exposure to polycyclic aromatic hydrocarbons with special focus on cancer

    Institute of Scientific and Technical Information of China (English)

    Thamaraiselvan; Rengarajan; Peramaiyan; Rajendran; Natarajan; Nandakumar; Boopathy; Lokeshkumar; Palaniswami; Rajendran; Ikuo; Nishigaki

    2015-01-01

    Polycyclie aromatic hydrocarbons(PAHs) are a group of compounds consisting of two or more fused aromatic rings.Most of them are formed during incomplete combustion of organic materials such as wood and fossil fuels,petroleum products,and coal.The composition of PAH mixtures varies with the source and is also affected by selective weathering effects in the environment.PAHs are ubiquitous pollutants frequently found in a variety of environments such as fresh water and marine sediments,the atmosphere,and ice.Due to their widespread distribution,the environmental pollution due to PAHs has aroused global concern.Many PAHs and their epoxides are highly toxic,mutagenic and/or carcinogenic to microorganisms as well as to higher forms of life including humans.The main aim of this review is to provide contemporary information on PAH sources,route of exposure,worldwide emission rate,and adverse effects on humans,especially with reference to cancer.

  4. DNS of compressible pipe flow exiting into a coflow

    International Nuclear Information System (INIS)

    Highlights: ► DNS conducted of turbulent pipe flow exiting into a coflow. ► Varied Mach number and coflow velocity. ► Statistics near nozzle collapse using wall-shear stress and density from upstream. ► Asymptotic theory can be used to qualitatively predict near-nozzle behaviour. ► Self-similarity of jets only found for small coflow magnitudes. - Abstract: Direct numerical simulations were conducted of a fully turbulent canonical nozzle/jet configuration. For all cases, the target Reynolds number, based on the jet velocity and diameter, was specified as 7500 and the jet Mach number and coflow Mach number were varied. Turbulence statistics at the nozzle exit are shown to collapse with fully developed turbulent pipe flow profiles when using the wall shear-stress, and in the case of higher Mach number cases also the wall density, from the fully developed flow region upstream in the nozzle. Predictions of flow variables in the near-nozzle region obtained from asymptotic theory are found to agree qualitatively with Direct Numerical Simulation data. The data from the different cases are shown to collapse in the potential core region when scaling with the appropriate mixing layer parameter while further downstream the appropriate parameter is the non-dimensional local velocity excess. For all scalings investigated, including virtual-origin correction of the streamwise axis, the case with the highest coflow magnitude did not agree well with the other cases implying that self-similarity of coflowing jets is restricted to low coflow values. Finally, it is shown that the acoustic field is resolved by the simulations making the data suitable for subsequent aeroacoustic analysis.

  5. Modelling guidelines for core exit temperature simulations with system codes

    International Nuclear Information System (INIS)

    Highlights: • Core exit temperature is used in PWRs as an indication of core heat up. • Modelling guidelines of CET response with system codes. • Modelling of heat transfer processes in the core and UP regions. - Abstract: Core exit temperature (CET) measurements play an important role in the sequence of actions under accidental conditions in pressurized water reactors (PWR). Given the difficulties in placing measurements in the core region, CET readings are used as criterion for the initiation of accident management (AM) procedures because they can indicate a core heat up scenario. However, the CET responses have some limitation in detecting inadequate core cooling and core uncovery simply because the measurement is not placed inside the core. Therefore, it is of main importance in the field of nuclear safety for PWR power plants to assess the capabilities of system codes for simulating the relation between the CET and the peak cladding temperature (PCT). The work presented in this paper intends to address this open question by making use of experimental work at integral test facilities (ITF) where experiments related to the evolution of the CET and the PCT during transient conditions have been carried out. In particular, simulations of two experiments performed at the ROSA/LSTF and PKL facilities are presented. The two experiments are part of a counterpart exercise between the OECD/NEA ROSA-2 and OECD/NEA PKL-2 projects. The simulations are used to derive guidelines in how to correctly reproduce the CET response during a core heat up scenario. Three aspects have been identified to be of main importance: (1) the need for a 3-dimensional representation of the core and Upper Plenum (UP) regions in order to model the heterogeneity of the power zones and axial areas, (2) the detailed representation of the active and passive heat structures, and (3) the use of simulated thermocouples instead of steam temperatures to represent the CET readings

  6. Noncomparative scaling of aromaticity through electron itinerancy

    International Nuclear Information System (INIS)

    Aromaticity is a multidimensional concept and not a directly observable. These facts have always stood in the way of developing an appropriate theoretical framework for scaling of aromaticity. In the present work, a quantitative account of aromaticity is developed on the basis of cyclic delocalization of π-electrons, which is the phenomenon leading to unique features of aromatic molecules. The stabilization in molecular energy, caused by delocalization of π-electrons is obtained as a second order perturbation energy for archetypal aromatic systems. The final expression parameterizes the aromatic stabilization energy in terms of atom to atom charge transfer integral, onsite repulsion energy and the population of spin orbitals at each site in the delocalized π-electrons. An appropriate computational platform is framed to compute each and individual parameter in the derived equation. The numerical values of aromatic stabilization energies obtained for various aromatic molecules are found to be in close agreement with available theoretical and experimental reports. Thus the reliable estimate of aromaticity through the proposed formalism renders it as a useful tool for the direct assessment of aromaticity, which has been a long standing problem in chemistry

  7. The "Wall Street Walk" and Shareholder Activism: Exit as a Form of Voice

    OpenAIRE

    Admati, Anat R; Pfleiderer, Paul C.

    2007-01-01

    We examine whether a large shareholder can alleviate conflicts of interest between managers and shareholders through the credible threat of exit on the basis of private information. In our model the threat of exit often reduces agency costs, but additional private information need not enhance the effectiveness of the mechanism. Moreover, the threat of exit can produce quite different effects depending on whether the agency problem involves desirable or undesirable actions from shareholders' p...

  8. Private Wealth and Job Exit at Older Age: a Random Effects Model

    OpenAIRE

    Bloemen, H.G.

    2008-01-01

    Forthcoming in 'Empirical Economics' . Private wealth holdings are likely to become an increasingly important determinant in the job exit decision of elderly workers. Net wealth may correlate with worker's characteristics that also determine the exit out of a job. It is therefore important to include a rich set of observed characteristics in an empirical model for retirement in order to measure the (marginal) effect of wealth on the job exit rate. But even with a rich set of regressors the qu...

  9. Non-Lytic, Actin-Based Exit of Intracellular Parasites from C. elegans Intestinal Cells

    OpenAIRE

    Estes, Kathleen A.; Szumowski, Suzannah C.; Troemel, Emily R.

    2011-01-01

    The intestine is a common site for invasion by intracellular pathogens, but little is known about how pathogens restructure and exit intestinal cells in vivo. The natural microsporidian parasite N. parisii invades intestinal cells of the nematode C. elegans, progresses through its life cycle, and then exits cells in a transmissible spore form. Here we show that N. parisii causes rearrangements of host actin inside intestinal cells as part of a novel parasite exit strategy. First, we show that...

  10. The Effect of High School Exit Exams on Graduation, Employment, Wages and Incarceration

    OpenAIRE

    Olesya Baker; Kevin Lang

    2013-01-01

    We evaluate the effects of high school exit exams on high school graduation, incarceration, employment and wages. We construct a state/graduation-cohort dataset using the Current Population Survey, Census and information on exit exams. We find relatively modest effects of high school exit exams except on incarceration. Exams assessing academic skills below the high school level have little effect. However, more challenging standards-based exams reduce graduation and increase incarceration rat...

  11. Bankruptcy as an exit mechanism for systems with a variable number of components

    Science.gov (United States)

    Delli Gatti, Domenico; Di Guilmi, Corrado; Gaffeo, Edoardo; Gallegati, Mauro

    2004-12-01

    Dynamical systems with components whose sizes evolve according to multiplicative stochastic rules have been recently combined with entry and exit processes. We show that the assumptions usually made in modeling exits are at odds with the available evidence. We discuss a recently proposed macroeconomic model with random multiplicative shocks and a mechanism for exit based on bankruptcy, which displays several observed stylized facts for firms' dynamics, like power law distributions for firms' sizes and Laplace distributions for firms' growth rates.

  12. Environmental Behaviors and Toxicities of Polycyclic Aromatic Hydrocarbons and Nitropolycyclic Aromatic Hydrocarbons.

    Science.gov (United States)

    Hayakawa, Kazuichi

    2016-01-01

    Airborne particulate matter (PM) has been collected at four cities in Japan starting in the late 1990s, at five or more major cities in China, Korea and Russia starting in 2001 and at the Noto Peninsula starting in 2004. Nine polycyclic aromatic hydrocarbons (PAHs) and eleven nitropolycyclic aromatic hydrocarbons (NPAHs) were determined by HPLC with fluorescence and chemiluminescence detections, respectively. Annual concentrations of PAHs and NPAHs were in the order, China>Russia≫Korea=Japan, with seasonal change (winter>summer). During the observation period, concentrations of PAHs and NPAHs in Japanese cities significantly decreased but the increases in the PAH concentration were observed in Chinese and Russian cities. Concentrations of PAHs and NPAHs were higher in the Northern China than those in the Southern China. At the Noto peninsula, which is in the main path of winter northwest winds and a year-round jet stream that blow from the Asian continent to Japan, the concentrations were high in winter and low in summer every year. A cluster analysis and back trajectory analysis indicated that PAHs and NPAHs were long-range transported from Northeastern China, where coal burning systems such as coal-heating boilers are considered to be the major contributors of PAHs and NPAHs. A dramatic change in atmospheric concentrations of PAHs and NPAHs in East Asia suggests the rapid and large change of PM2.5 pollution in East Asia. Considering the adverse health effects of PM2.5, continuous monitoring of atmospheric PAHs and NPAHs is necessary in this area. PMID:26833435

  13. Distribution of aliphatic and polycyclic aromatic hydrocarbon in South China sea sediments

    International Nuclear Information System (INIS)

    Petroleum hydrocarbon (Hcp) consist of three major components namely alkanes, cyclo-alkanes and aromatics. HCP are pollutant and can cause adverse effect to the marine organisms. The study was done to identify the source of pollution in the South China Sea coastal area. The South China Sea is one of the major oil production area in Malaysia. Sampling was done at 15 stations along the coastal area of South China Sea off Peninsular Malaysia, which involved two zone namely coastal (zone 1) and offshore (zone 2) areas. Samples were analyzed using GC-MS for determination of HCP. The results showed, that concentration of aliphatic and polycyclic aromatic hydrocarbon at coastal area, range from 0.51 - 1.31 mg/g and 0.18 - 0.42 mg/g dry weight, respectively whilst, concentration of aliphatic and polycyclic aromatic hydrocarbon at offshore area, range from 0.44 - 1.09 mg/g and 0.20 - 0.49 mg/g dry weight, respectively. SHCP (Aliphatic + PAH) concentration in the sediment at the study area range from 0.64 - 1.68 mg/g dry weight. In this study, it was found that, pollution source for the South China Sea off Peninsular Malaysia was originated from pyrolytic sources (combustion fossil fuel), while some other area had been polluted by pyrolytic or petrogenic (unburned fossil) sources. (Author)

  14. Water Pollution

    Science.gov (United States)

    ... phosphorus make algae grow and can turn water green. Bacteria, often from sewage spills, can pollute fresh or salt water. You can help protect your water supply: Don't pour household products such as cleansers, beauty products, medicines, auto fluids, paint, and lawn care ...

  15. Water Pollution

    Science.gov (United States)

    We all need clean water. People need it to grow crops and to operate factories, and for drinking and recreation. Fish and wildlife depend on ... and phosphorus make algae grow and can turn water green. Bacteria, often from sewage spills, can pollute ...

  16. Ambient PAH concentrations - results of long-term measurements of polycyclic aromatic hydrocarbons in Bavaria. PAK-Immissionskonzentrationen - Ergebnisse mehrjaehriger Messungen polycyclischer aromatischer Kohlenwasserstoffe in Bayern

    Energy Technology Data Exchange (ETDEWEB)

    Muecke, W.; Steinmetzer, H.C.; Stumpp, J. (Bayerisches Staatsministerium fuer Landesentwicklung und Umweltfragen, Muenchen (Germany)); Baumeister, W.; Boneberg, R.; Vierle, O. (Bayerisches Landesamt fuer Umweltschutz, Muenchen (Germany))

    1991-05-01

    Suspended particulate analyses were conducted in representative residential areas over longer periods, and 14 selected polycyclic aromatic hydrocarbons (PAHs) analysed within this framework (in accordance with the VDI quideline 3875, Sheet 1). The results show that in urban agglomerations significant regional differences exist, as a function of the emission situation, in the levels of atmospheric pollution through particle-bound PAH. A reduction of the total pollution has been achieved in recent years though air pollution control measures. (BBR).

  17. Early childhood lower respiratory illness and air pollution

    Czech Academy of Sciences Publication Activity Database

    Hertz-Picciotto, I.; Baker, R. J.; Yap, P.S.; Dostál, Miroslav; Joad, J.P.; Lipsett, M.; Greenfield, T.; Herr, C.E.W.; Beneš, I.; Shumway, R.H.; Pinkerton, K.E.; Šrám, Radim

    2007-01-01

    Roč. 115, č. 10 (2007), s. 1510-1518. ISSN 0091-6765 R&D Projects: GA MŽP SL/5/160/05 Institutional research plan: CEZ:AV0Z50390512 Keywords : air pollution * polycyclic aromatic hydrocarbons * particulate matter Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 5.636, year: 2007

  18. BIOTRANSFORMATION OF PRIORITY POLLUTANTS USING BIOFILMS AND VASCULAR PLANTS

    Science.gov (United States)

    Microbial filters with and without reeds (Phragmites communis) were used to degrade aromatic and aliphatic organics on the EPA priority pollutant list. The initial concentrations of the organics were in the range of 400-1000 micrograms/l. The contaminated river water was treated ...

  19. Quantum transport through aromatic molecules

    International Nuclear Information System (INIS)

    In this paper, we study the electronic transport properties through aromatic molecules connected to two semi-infinite leads. The molecules are in different geometrical configurations including arrays. Using a nearest neighbor tight-binding approach, the transport properties are analyzed into a Green's function technique within a real-space renormalization scheme. We calculate the transmission probability and the Current-Voltage characteristics as a function of a molecule-leads coupling parameter. Our results show different transport regimes for these systems, exhibiting metal-semiconductor-insulator transitions and the possibility to employ them in molecular devices

  20. Substrate specific hydrolysis of aromatic and aromatic-aliphatic esters in orchid tissue cultures

    OpenAIRE

    Agnieszka Mironowicz; Krystyna Kukułczanka; Antoni Siewiński

    2014-01-01

    We found that tissue cultures of higher plants were able, similarly as microorganisms, to transform low-molecular-weight chemical compounds. In tissue cultures of orchids (Cymbidium 'Saint Pierre' and Dendrobium phalaenopsis) acetates of phenols and aromatic-aliphatic alcohols were hydrolyzed, whereas methyl esters of aromatic and aromatic-aliphatic acids did not undergo this reaction. Acetates of racemic aromatic-aliphatic alcohols were hydrolyzed with distinct enantiospecificity.

  1. Polycyclic aromatic hydrocarbons in insular and coastal soils of the Russian Arctic

    Science.gov (United States)

    Abakumov, E. V.; Tomashunas, V. M.; Lodygin, E. D.; Gabov, D. N.; Sokolov, V. T.; Krylenkov, V. A.; Kirtsideli, I. Yu.

    2015-12-01

    The content and individual component compositions of polycyclic aromatic hydrocarbons in polar soils of the Russian Arctic sector have been studied. The contamination of soils near research stations is identified from the expansion of the range of individual polycyclic aromatic hydrocarbons, the abrupt increase in the content of heavy fractions, and the accumulation of benzo[ a]pyrene. Along with heavy hydrocarbons, light hydrocarbons (which are not only natural compounds, but also components of organic pollutants) are also accumulated in the contaminated soils. Heavy polycyclic aromatic hydrocarbons are usually of technogenic origin and can serve as markers of anthropogenic impact in such areas as Cape Sterligov, Cape Chelyuskin, and the Izvestii TsIK Islands. The content of benzo[ a]pyrene, the most hazardous organic toxicant, appreciably increases in soils around the stations, especially compared to the control; however, the level of MPC is exceeded only for the soils of Cape Chelyuskin.

  2. Re-Examining Exit Exams: New Findings from the Education Longitudinal Study of 2002

    Science.gov (United States)

    Shuster, Kate

    2012-01-01

    Using the nationally representative, cohort-based data of the Education Longitudinal Study of 2002 (ELS:02), this study employs multiple regression to examine the effects of exit exams on student achievement and school completion. This study finds that exit exams as a whole do not have substantial effects on student achievement in mathematics,…

  3. Application of an entry-exit tariff model to the gas transport system in Spain

    International Nuclear Information System (INIS)

    Under an entry-exit gas tariff system, reservation of capacity is split into entry capacity, to transport gas from the injection points to a virtual balancing point, and exit capacity, to transport gas from the balancing point to the exit points in the system. Entry-exit tariff for gas transport systems have been recommended by the 3rd EU Energy Package, since they are cost reflective, facilitate gas trade and can provide signals for the location of gas injections or off-takes. The advisability of applying an entry-exit tariff system is discussed in this paper. Apart from this, authors propose an entry-exit tariff model and apply it to compute charges for the Spanish gas transport system in 2009. Results produced by the model are presented as coefficients which should multiply the current postal transport tariff. The paper concludes that entry-exit tariffs would be useful location signals which would result in a better use of the gas transport system in Spain. In those cases where demand exceeds available capacity, as it occurs at the congested connection with France, entry-exit tariffs could be supplemented by capacity charges at entry points resulting from auctions. (author)

  4. Application of an entry-exit tariff model to the gas transport system in Spain

    International Nuclear Information System (INIS)

    Under an entry-exit gas tariff system, reservation of capacity is split into entry capacity, to transport gas from the injection points to a virtual balancing point, and exit capacity, to transport gas from the balancing point to the exit points in the system. Entry-exit tariff for gas transport systems have been recommended by the 3rd EU Energy Package, since they are cost reflective, facilitate gas trade and can provide signals for the location of gas injections or off-takes. The advisability of applying an entry-exit tariff system is discussed in this paper. Apart from this, authors propose an entry-exit tariff model and apply it to compute charges for the Spanish gas transport system in 2009. Results produced by the model are presented as coefficients which should multiply the current postal transport tariff. The paper concludes that entry-exit tariffs would be useful location signals which would result in a better use of the gas transport system in Spain. In those cases where demand exceeds available capacity, as it occurs at the congested connection with France, entry-exit tariffs could be supplemented by capacity charges at entry points resulting from auctions.

  5. Visual Barriers to Prevent Ambulatory ALzheimer's Patients from Exiting through an Emergency Door.

    Science.gov (United States)

    Namazi, Kevan H.; And Others

    1989-01-01

    Conducted study on Alzheimer's unit to test seven different visual barrier conditions for reducing patient exits. Findings indicated that exiting was eliminated under two conditions. Results suggest visual agnosia, the inability to interpret what the eye sees, may be used as tool in managing wandering behavior of Alzheimer's patients. (Author/NB)

  6. 29 CFR 1910.36 - Design and construction requirements for exit routes.

    Science.gov (United States)

    2010-07-01

    ....36 Section 1910.36 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Means of Egress § 1910.36 Design and... your workplace, consult NFPA 101-2000, Life Safety Code. (c) Exit discharge. (1) Each exit...

  7. Non-lytic, actin-based exit of intracellular parasites from C. elegans intestinal cells.

    Directory of Open Access Journals (Sweden)

    Kathleen A Estes

    2011-09-01

    Full Text Available The intestine is a common site for invasion by intracellular pathogens, but little is known about how pathogens restructure and exit intestinal cells in vivo. The natural microsporidian parasite N. parisii invades intestinal cells of the nematode C. elegans, progresses through its life cycle, and then exits cells in a transmissible spore form. Here we show that N. parisii causes rearrangements of host actin inside intestinal cells as part of a novel parasite exit strategy. First, we show that N. parisii infection causes ectopic localization of the normally apical-restricted actin to the basolateral side of intestinal cells, where it often forms network-like structures. Soon after this actin relocalization, we find that gaps appear in the terminal web, a conserved cytoskeletal structure that could present a barrier to exit. Reducing actin expression creates terminal web gaps in the absence of infection, suggesting that infection-induced actin relocalization triggers gap formation. We show that terminal web gaps form at a distinct stage of infection, precisely timed to precede spore exit, and that all contagious animals exhibit gaps. Interestingly, we find that while perturbations in actin can create these gaps, actin is not required for infection progression or spore formation, but actin is required for spore exit. Finally, we show that despite large numbers of spores exiting intestinal cells, this exit does not cause cell lysis. These results provide insight into parasite manipulation of the host cytoskeleton and non-lytic escape from intestinal cells in vivo.

  8. 36 CFR 13.1312 - Climbing and walking on Exit Glacier.

    Science.gov (United States)

    2010-07-01

    ... Glacier. 13.1312 Section 13.1312 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF... General Provisions § 13.1312 Climbing and walking on Exit Glacier. Except for areas designated by the Superintendent, climbing or walking on, in, or under Exit Glacier is prohibited within 1/2 mile of the...

  9. Non-lytic, actin-based exit of intracellular parasites from C. elegans intestinal cells.

    Science.gov (United States)

    Estes, Kathleen A; Szumowski, Suzannah C; Troemel, Emily R

    2011-09-01

    The intestine is a common site for invasion by intracellular pathogens, but little is known about how pathogens restructure and exit intestinal cells in vivo. The natural microsporidian parasite N. parisii invades intestinal cells of the nematode C. elegans, progresses through its life cycle, and then exits cells in a transmissible spore form. Here we show that N. parisii causes rearrangements of host actin inside intestinal cells as part of a novel parasite exit strategy. First, we show that N. parisii infection causes ectopic localization of the normally apical-restricted actin to the basolateral side of intestinal cells, where it often forms network-like structures. Soon after this actin relocalization, we find that gaps appear in the terminal web, a conserved cytoskeletal structure that could present a barrier to exit. Reducing actin expression creates terminal web gaps in the absence of infection, suggesting that infection-induced actin relocalization triggers gap formation. We show that terminal web gaps form at a distinct stage of infection, precisely timed to precede spore exit, and that all contagious animals exhibit gaps. Interestingly, we find that while perturbations in actin can create these gaps, actin is not required for infection progression or spore formation, but actin is required for spore exit. Finally, we show that despite large numbers of spores exiting intestinal cells, this exit does not cause cell lysis. These results provide insight into parasite manipulation of the host cytoskeleton and non-lytic escape from intestinal cells in vivo. PMID:21949650

  10. Wives' Relative Wages, Husbands' Paid Work Hours, and Wives' Labor-Force Exit

    Science.gov (United States)

    Shafer, Emily Fitzgibbons

    2011-01-01

    Economic theories predict that women are more likely to exit the labor force if their partners' earnings are higher and if their own wage rate is lower. In this article, I use the National Longitudinal Survey of Youth (N = 2,254) and discrete-time event-history analysis to show that wives' relative wages are more predictive of their exit than are…

  11. 14 CFR 91.607 - Emergency exits for airplanes carrying passengers for hire.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Emergency exits for airplanes carrying... Emergency exits for airplanes carrying passengers for hire. (a) Notwithstanding any other provision of this chapter, no person may operate a large airplane (type certificated under the Civil Air...

  12. The Impact of High School Exit Exams on ESL Learners in British Columbia

    Science.gov (United States)

    Odo, Dennis Murphy

    2012-01-01

    This essay explores the validity of including ELL students in British Columbia provincial high school exit exams. Data and a sample exam from the BC Ministry of education are used to scrutinize the practice of using BC provincial exams for high school exit decisions regarding ELLs. A comparison of failure rates of ELLs and mainstream students…

  13. The EXIT for Prenatally Diagnosed Cervical Cystic Teratoma: A Case Report

    Directory of Open Access Journals (Sweden)

    Sabri Cansaran

    2015-03-01

    Full Text Available The Ex-utero intrapartum treatment (EXIT is a procedure performed during caesarean section while on fetal-placental circulation. We present a prenatally diagnosed cervical cystic mass causing tracheal compression which was managed successfully with the EXIT procedure.

  14. Rif-Recall as Symbol and Signal: The Differential Effects of Riffing on Teacher Exit Choices.

    Science.gov (United States)

    Gehrke, Nathalie; Sheffield, Rosemary

    A case study of 1100 high school teachers in a large urban district that has experienced declining enrollment for eight years illustrates several of the exit options and career mobility effects of riffing (reduction in force). The findings show that during decline, freely chosen movement out (exit), or laterally (moderate number of location…

  15. Mean Exit Time and Survival Probability within the CTRW Formalism

    CERN Document Server

    Montero, M; Montero, Miquel; Masoliver, Jaume

    2006-01-01

    An intense research on financial market microstructure is presently in progress. Continuous time random walks (CTRWs) are general models capable to capture the small-scale properties that high frequency data series show. The use of CTRW models in the analysis of financial problems is quite recent and their potentials have not been fully developed. Here we present two (closely related) applications of great interest in risk control. In the first place, we will review the problem of modelling the behaviour of the mean exit time (MET) of a process out of a given region of fixed size. The surveyed stochastic processes are the cumulative returns of asset prices. The link between the value of the MET and the timescale of the market fluctuations of a certain degree is crystal clear. In this sense, MET value may help, for instance, in deciding the optimal time horizon for the investment. The MET is, however, one among the statistics of a distribution of bigger interest: the survival probability (SP), the likelihood t...

  16. OPERATORS ON CORNER MANIFOLDS WITH EXIT TO INFINITY

    Institute of Scientific and Technical Information of China (English)

    D. Calvo; B. W. Schulze

    2006-01-01

    We study (pseudo-)differential operators on a manifold with edge Z,locally modelled on a wedge with model cone that has itself a base manifold W with smooth edge Y. The typical operators A are corner degenerate in a specific way. They (σψ (A), σ∧ (A), σ∧ (A)), where σψ is the interior symbol and σ∧ (A)(y, η), (y, η) ∈ T*Y\\0,weighted Sobolev spaces on the infinite cone with base W. Since such a cone has edges with exit to infinity, the calculus has the problem to understand the behaviour of operators on a manifold of that kind.We show the continuity of corner-degenerate operators in weighted edge Sobolev spaces, and we investigate the ellipticity of edge symbols of second generation. Starting from parameter-dependent elliptic families of edge operators of first generation, we obtain the Fredholm property of higher edge symbols on the corresponding singular infinite model cone.

  17. Exit Noise Summer Fest: Explaining the audience in ethnographic discourse

    Directory of Open Access Journals (Sweden)

    Lukić-Krstanović Miroslava M.

    2005-01-01

    Full Text Available In Ethnology, studying festivals is a relevant activity since it could enlighten a number of complex cultural and social processes. The festivals represent public events, public ceremonies, cluster of rituals and produce many symbols, and as such, they are in fact a creative reflection of a society. In this paper, we analyze the Exit Noise Summer Fest, the biggest music festival in SE Europe. The aim of the analysis is to gain understanding of the cultural event of this kind and its protagonists, namely, the audience. Shedding a light to a music spectacle, from a standpoint of social and symbolic communication, directs to a different perspective in reading of rituals, communities zones, and semantic constructions of noise and body in the center of ritual behaviors. The research shows that the music experience and atmosphere of the celebration, though having somewhat unclear ritual borderline and zone, are compatible with the daily culture and social processes, in which the event is created and further reflects itself through various mediums.

  18. Folding and escape of nascent proteins at ribosomal exit tunnel

    Science.gov (United States)

    Bui, Phuong Thuy; Hoang, Trinh Xuan

    2016-03-01

    We investigate the interplay between post-translational folding and escape of two small single-domain proteins at the ribosomal exit tunnel by using Langevin dynamics with coarse-grained models. It is shown that at temperatures lower or near the temperature of the fastest folding, folding proceeds concomitantly with the escape process, resulting in vectorial folding and enhancement of foldability of nascent proteins. The concomitance between the two processes, however, deteriorates as temperature increases. Our folding simulations as well as free energy calculation by using umbrella sampling show that, at low temperatures, folding at the tunnel follows one or two specific pathways without kinetic traps. It is shown that the escape time can be mapped to a one-dimensional diffusion model with two different regimes for temperatures above and below the folding transition temperature. Attractive interactions between amino acids and attractive sites on the tunnel wall lead to a free energy barrier along the escape route of the protein. It is suggested that this barrier slows down the escape process and consequently promotes correct folding of the released nascent protein.

  19. Core compressor exit stage study. 1: Aerodynamic and mechanical design

    Science.gov (United States)

    Burdsall, E. A.; Canal, E., Jr.; Lyons, K. A.

    1979-01-01

    The effect of aspect ratio on the performance of core compressor exit stages was demonstrated using two three stage, highly loaded, core compressors. Aspect ratio was identified as having a strong influence on compressors endwall loss. Both compressors simulated the last three stages of an advanced eight stage core compressor and were designed with the same 0.915 hub/tip ratio, 4.30 kg/sec (9.47 1bm/sec) inlet corrected flow, and 167 m/sec (547 ft/sec) corrected mean wheel speed. The first compressor had an aspect ratio of 0.81 and an overall pressure ratio of 1.357 at a design adiabatic efficiency of 88.3% with an average diffusion factor or 0.529. The aspect ratio of the second compressor was 1.22 with an overall pressure ratio of 1.324 at a design adiabatic efficiency of 88.7% with an average diffusion factor of 0.491.

  20. Partition of polycyclic aromatic hydrocarbons on organobentonites

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of organobentonites synthesized by exchanging organiccation such as dodecyltri-methylammonium (DTMA),benzyldimethyltetradecylammonium (BDTDA), cetyltrimethyl-ammonium (CTMA), octodeyltrimethylammonium (OTMA) on bentonite. The optimal condition, properties and mechanisms for the organobentonites to sorb phenanthrene, anthracene, naphthalene, acenaphthene in water were investigated in detail. The partition behavior was determined for four polycyclic aromatic hydrocarbons (PAHs), such as naphthalene, phenanthrene, anthracene and acenaphthene, from water to a series of organobentonites. The interlayer spacings and organic carbon contents of organobentonites, removal rate and sorption capacities for organobentonites to treat phenanthrene,anthracene, naphthalene, acenaphthene were correlated to the length of alkyl chains and the amounts of cation surfactant exchanged on Foundation item: the bentonite. Phenanthrene, anthracene, naphthalene, and acenaphthene sorption to organobentonites were characterized by linear isotherms, indicating solute partition between water and the organic phase composed of the large alkyl functional groups of quaternary ammonium cations. PAHs distribution coefficients (Kd)between organobentonites and water were proportional to the organic carbon contents of organobentonites. However, the partition coefficients (Koc) were nearly constants for PAHs in the system of organobentonite-water. The Koc of phenanthrene, anthracene,naphthalene, acenaphthene were 2.621x105, 2.106x105, 2.247x104,5.085x104, respectively. The means Koc values on the organobentonites are about ten to twenty times larger than the values on the soils/sediments, what is significant prerequisite for organobentonite to apply to remediation of pollution soil and groundwater. The sorption mechanism was also evaluated from octanol-water partition coefficients and aqueous solubility of PAHs. The correlations between lgKoc and 1gkow, 1gKoc and 1gS for PAHs in the system of water

  1. Genome Sequence of Pseudomonas aeruginosa DQ8, an Efficient Degrader of n-Alkanes and Polycyclic Aromatic Hydrocarbons

    OpenAIRE

    Gai, Zhonghui; Zhang, Zhengzhi; Wang, Xiaoyu; Tao, Fei; Tang, Hongzhi; Xu, Ping

    2012-01-01

    Pseudomonas aeruginosa DQ8, which was isolated from the crude oil polluted soil in the Daqing oilfield of China, can efficiently degrade diesel, crude oil, n-alkanes, and polycyclic aromatic hydrocarbons (PAHs). Here, we present a 6.8-Mb assembly of its genome sequence. We have annotated 23 coding sequences (CDSs) responsible for catabolism of n-alkanes and PAHs.

  2. Distribution of Polycyclic aromatic hydrocarbons between water, sediment and common eels (Anguilla angillae) in the urban stretch of Tevere River

    International Nuclear Information System (INIS)

    The research has focused the attention on the occurrence of polycyclic aromatic hydrocarbons (PAHs) in water, sediment and common eels (Angilla anguillae) in the urban area of Tevere River. These compounds can derived from point (E.g.oil spill) or non-point (e.g. atmospheric deposition) sources and are one of the most widespread organic pollutants. (Author)

  3. Repair of DNA damage induced by anthanthrene, a polycyclic aromatic hydrocarbon (PAH) without bay or fjord regions

    DEFF Research Database (Denmark)

    Madsen, Claus Desler; Johannessen, Christian; Rasmussen, Lene Juel

    2009-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants, formed during incomplete burning of coal, oil and gas. Several PAHs have carcinogenic and mutagenic potencies, but these compounds must be activated in order to exert their mutagenic effects. One of the principal pathways...

  4. Optimization of exit pupil function: improvement on the OTF of full parallax holographic stereograms

    International Nuclear Information System (INIS)

    The wavefront reconstructed errors of full parallax holographic stereograms are analysed. The optical transfer function (OTF) is simulated to investigate frequency response and imaging quality of holographic stereogram systems. The behaviour of the OTF with respect to slit size and spatial frequency in different aberrations is described and used to optimize the exit pupil function. The shaped window function (Gaussian and Blackman) is proposed to be used as the exit pupil function of holographic systems, and the influence of different exit pupil functions on the OTF is investigated in detail. The calculated results show that the shaped exit pupil function with optimized slit size can improve the imaging quality of full parallax holographic stereogram systems effectively. The design criterion of the exit pupil function is also discussed. (paper)

  5. In vitro toxicity of polycyclic aromatic hydrocarbons and halogenated aromatic hydrocarbons to cetacean cells and tissues

    Energy Technology Data Exchange (ETDEWEB)

    Carvan, M.J. III.

    1993-01-01

    Cetaceans bioaccumulate high aromatic hydrocarbon tissue residues, and elevated levels of PCB residues in tissues are proposed to have occurred concurrently with recent epizootic deaths of dolphins. The objectives of this study were: (1) to develop and characterize an epithelial cell line derived from dolphin tissues, (2) to investigate the effects of hydrocarbon pollutants on those cells, and (3) to analyze the toxicity of hydrocarbon pollutants on cetacean tissues in vitro. An epithelial cell line, Carvan dolphin kidney (CDK), isolated from a spontaneously aborted female bottlenose dolphin, Tursiops truncatus, grew rapidly. These cells were neither transformed nor immortal. Velocity sedimentation analysis showed CDK cells contained nuclear aryl hydrocarbon receptor, suggestive of cytochrome P450 inducibility. BaP inhibited mitosis in CDK cells in a dose-dependent manner. Data indicate that CDK cells metabolize BaP, that BaP metabolites bind to cellular DNA initiating unscheduled DNA synthesis, and that the inhibition of cytochrome P450 metabolism decrease the BaP-associated inhibition of mitosis in dolphin cells. The data also suggest that TCDD acts synergistically to increase the levels of DNA damage by the procarcinogen BaP. Cetacean liver microsomes was isolated and evaluated for the presence of cytochrome P450 proteins by SDS-PAGE, apparent minimum molecular weight determination, and immunoblot analysis. P450 activity was induced in cetacean tissue samples and CDK cells by exposure in vitro to one of several cytochrome P450-inducing chemicals. The data suggest that cetacean tissues and cells can be utilized to study the in vitro induction of cytochrome P450, resultant metabolism of xenobiotic contaminants, and the subsequent cellular and molecular responses. However, the identity of specific P450 isozymes involved in this process will remain undetermined until monoclonal antibodies that recognize cetacean P450s can be generated.

  6. Hazardous Air Pollutants

    Science.gov (United States)

    ... Facebook Twitter Google+ Pinterest Contact Us Hazardous Air Pollutants Hazardous air pollutants are those known to cause ... protect against adverse environmental effects. About Hazardous Air Pollutants What are hazardous air pollutants? Health and Environmental ...

  7. The Internet Pollution

    Institute of Scientific and Technical Information of China (English)

    唐宁宁

    2005-01-01

    Life today has brought new problems. As we know, there are fourterrible pollutions in the world: water pollution, noise pollution, air pol-lution and rubbish pollution. Water pollution kills our fish and pollutesour drinking water. Noise pollution makes us talk louder and become angry more easily. Air pollution makes us hold our breath longer and be badto all living things in the world. Rubbish pollution often makes our livingenvironment much dirtier. But I think that the Internet pollution is anothernew pollution in the world.

  8. Beyond organic chemistry: aromaticity in atomic clusters.

    Science.gov (United States)

    Boldyrev, Alexander I; Wang, Lai-Sheng

    2016-04-28

    We describe joint experimental and theoretical studies carried out collaboratively in the authors' labs for understanding the structures and chemical bonding of novel atomic clusters, which exhibit aromaticity. The concept of aromaticity was first discovered to be useful in understanding the square-planar unit of Al4 in a series of MAl4(-) bimetallic clusters that led to discoveries of aromaticity in many metal cluster systems, including transition metals and similar cluster motifs in solid compounds. The concept of aromaticity has been found to be particularly powerful in understanding the stability and bonding in planar boron clusters, many of which have been shown to be analogous to polycyclic aromatic hydrocarbons in their π bonding. Stimulated by the multiple aromaticity in planar boron clusters, a design principle has been proposed for stable metal-cerntered aromatic molecular wheels of the general formula, M@Bn(k-). A series of such borometallic aromatic wheel complexes have been produced in supersonic cluster beams and characterized experimentally and theoretically, including Ta@B10(-) and Nb@B10(-), which exhibit the highest coordination number in two dimensions. PMID:26864511

  9. Determination of polycyclic aromatic hydrocarbons in water using an electrochemical DNA biosensor

    OpenAIRE

    R Manaffar; B Sehatnia; R Sabzi; Ehsani, A.

    2015-01-01

    Background and Objectives: Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants in aquatic environments. These contaminants are generated through oil spills, manufactory processes, and industrial wastes or naturally through the incomplete combustion of coal, oil, gas, and wood waste. Most of these compounds are noted as carcinogenic and mutagenic. Therefore, detection of these pollutants by a sensitive and inexpensive method is very important. Materials and Method...

  10. Sexual maturation in relation to polychlorinated aromatic hydrocarbons: Sharpe and Skakkebaek's hypothesis revisited

    OpenAIRE

    Den Hond, Elly; Roels, Harry A.; Hoppenbrouwers, Karel; Nawrot, Tim; Thijs, Lutgarde; Vandermeulen, Corinne; Winneke, Gerhard; Vanderschueren, Dirk; Staessen, Jan A.

    2002-01-01

    Polychlorinated aromatic hydrocarbons (PCAHs) have been described as endocrine disruptors in animals and in accidentally or occupationally exposed humans. In the present study we examined the effect of moderate exposure to PCAHs on sexual maturation. Two hundred adolescents (mean age, 17.4 years) who resided in two polluted suburbs and a rural control area in Flanders (Belgium) participated. We measured the serum concentration of polychlorinated biphenyl (PCB) congeners 138, 153, and 180 and ...

  11. Ex-situ bioremediation of polycyclic aromatic hydrocarbons in sewage sludge

    DEFF Research Database (Denmark)

    Schmidt, Jens Ejbye; Larsen, S.B.; Karakashev, Dimitar Borisov

    2008-01-01

    Polycyclic aromatic hydrocarbons (PAH) are naturally occurring organic compounds. As a result of anthropogenic activities, PAH concentration has increased in the environment considerably. PAH are regarded as environmental pollutants because they have toxic, mutagenic and carcinogenic effects on....... Primary and mixed (primary: secondary sludge = 1:3) sewage sludges were collected from a waste water treatment plant (WWTP) and degraded under mesophilic anaerobic conditions. The primary and mixed sludge produced separately from this digestion was used for three bioaugmentation batch experiments: firstly...

  12. Polycyclic Aromatic Hydrocarbons Identification and Source Discrimination in Rural Soil of the Northern Persian Gulf Coast

    OpenAIRE

    Fatemeh Valizadeh-kakhki; Mohamad Pauzi Zakaria; Ahmad Zaharin Aris; Syaizwan Zahmir Zulkifli; Mehdi Mohammadi; Hasan Tajik

    2014-01-01

    Due to strategic situation of the Persian Gulf, identifying the petroleum pollution level and source is an important issue. Therefore, this paper enhanced fingerprinting method of applying biomarkers Polycyclic Aromatic Hydrocarbons (PAHs) in identifying source and distribution of oil spills of the exposed areas. 10 soil samples collected from the northern coasts of the Persian Gulf along three provinces in the south of Iran. PAH concentrations in the soil ranged from 42.76 to 5596.49 ng.g-1....

  13. POLYCYCLIC AROMATIC HYDROCARBON CONTAMINATION LEVELS IN COLLECTED SAMPLES FROM VICINITY OF A HIGHWAY

    Directory of Open Access Journals (Sweden)

    S. V. Samimi ، R. Akbari Rad ، F. Ghanizadeh

    2009-01-01

    Full Text Available Tehran as the biggest city of Iran with a population of more than 10 millions has potentially high pollutant exposures of gas oil and gasoline combustion from vehicles that are commuting in the highways every day. The vehicle exhausts contain polycyclic aromatic hydrocarbons, which are produced by incomplete combustion and can be directly deposited in the environment. In the present study, the presence of polycyclic aromatic hydrocarbons contamination in the collected samples of a western highway in Tehran was investigated. The studied location was a busy highway in Tehran. High performance liquid chromatography equipped with florescence detector was used for determination of polycyclic aromatic hydrocarbons concentrations in the studied samples. Total concentration of the ten studied polycyclic aromatic hydrocarbons compounds ranged from 11107 to 24342 ng/g dry weight in the dust samples and increased from 164 to 2886 ng/g dry weight in the soil samples taken from 300 m and middle of the highway, respectively. Also the average of Σ PAHs was 1759 ng/L in the water samples of pools in parks near the highway. The obtained results indicated that polycyclic aromatic hydrocarbons contamination levels were very high in the vicinity of the highway.

  14. The History of Petroleum Pollution in Malaysia; Urgent Need for Integrated Prevention Approach

    OpenAIRE

    Mahyar Sakari

    2010-01-01

    Petroleum pollution is known as point and non-point source of contaminations in the environment. A major class of petroleum contaminant is groups of compounds consist of two or more fused benzene rings called polycyclic aromatic hydrocarbons (PAHs) that are carcinogenic, mutagenic and toxic. Source identification of petroleum pollution is necessary to prevent pollution entry into the environment. Eight sedimentary cores were obtained from developed and developing areas around Peninsular Malay...

  15. Approaches to the Assessment of the Efficiency of Remediation of Oil-Polluted Soils

    Science.gov (United States)

    Anchugova, E. M.; Melekhina, E. N.; Markarova, M. Yu.; Shchemelinina, T. N.

    2016-02-01

    Indices characterizing the enzymatic activity of soils and the contents of aliphatic and polycyclic aromatic hydrocarbons have been applied for estimating the efficiency of remediation of oil-polluted soils in the north of European Russia. Oil-polluted test plots treated with the Universal and Roder biopreparations and subjected to the agrochemical reclamation have been examined. The suggested indices can be used to diagnose and monitor the oil-polluted soils and to assess the efficiency of their remediation.

  16. Water Pollution. Project COMPSEP.

    Science.gov (United States)

    Lantz, H. B., Jr.

    This is an introductory program on water pollution. Examined are the cause and effect relationships of water pollution, sources of water pollution, and possible alternatives to effect solutions from our water pollution problems. Included is background information on water pollution, a glossary of pollution terminology, a script for a slide script…

  17. The content of organic material, n-alkana, aromatic compound and hydrocarbon total in the sediment was carried out in the waters of Raha, Southeast of Sulawesi

    OpenAIRE

    Muhajir Marsaoli

    2004-01-01

    Investigation on content of organic material, n-alkana, aromatic compound and hydrocarbon total in the sediment was carried out in the waters of Raha, Southeast of Sulawesi in June 2001. The results showed that the sediment at station 1 and 4 were polluted by hydrocarbon compound. This condition is showed by F1/F2 ratio (comparation between saturated hydrocarbon fraction with aromatic hydrocarbons fraction) > 1. According to NAS (National Academy of Science) criteria on total hydrocarbon cont...

  18. Exit Survey of Senior Residents: Cost Conscious but Uninformed.

    Science.gov (United States)

    Long, Theodore; Silvestri, Mark T; Dashevsky, Meir; Halim, Andrea; Fogerty, Robert L

    2016-05-01

    Background Cost awareness, to ensure physician stewardship of limited resources, is increasingly recognized as an important skill for physicians. The Accreditation Council for Graduate Medical Education has made cost awareness part of systems-based practice, a core competency of resident education. However, little is known about resident cost awareness. Objective We sought to assess senior resident self-perceived cost awareness and cost knowledge. Methods In March 2014, we conducted a cross-sectional survey of all emergency medicine, internal medicine, obstetrics and gynecology, orthopaedic surgery pediatrics, and medicine-pediatrics residents in their final year at Yale-New Haven Hospital. The survey examined attitudes toward health care costs and residents' estimates of order prices. We considered resident price estimates to be accurate if they were between 50% and 200% of the Connecticut-specific Medicare price. Results We sent the survey to 84 residents and received 47 completed surveys (56% response rate). Although more than 95% (45 of 47) felt that containing costs is the responsibility of every clinician, and 49% (23 of 47) agreed that cost influenced their decision when ordering, only 4% (2 of 47) agreed that they knew the cost of tests being ordered. No residents accurately estimated the price of a complete blood count with differential, and only 2.1% (1 of 47) were accurate for a basic metabolic panel. The overall accuracy of all resident responses was 25%. Conclusions In our study, many trainees exit residency with self-identified deficiencies in knowledge about costs. The findings show the need for educational approaches to improve cost awareness among trainees. PMID:27168897

  19. GUTKA-A MALIGNANT ENTITY SEEKS BENIGN EXIT IN INDIA

    Directory of Open Access Journals (Sweden)

    Kharat

    2013-01-01

    Full Text Available ABSTRACT: Tobacco and its products have been a household entit y since a long time specially in Indian houses either as a pride to be snuffed thr ough the pipes or the traditional hookahs by the rajas maharajas, or if not through the smoke it took place in many untowardly customs and rituals associated. It has spread through the subcon tinent, and even to the other countries. Promoted by a slick and many- tentacled advertising campaign, gutka, an indigenous form of smokeless tobacco, has become a fixture in the mout hs of millions of Indians over the last two decades. But what has prompted particular concern her e is the way that in the last 10 years, gutka as portable as chewing gum and sometimes as sw eet as candy has found its way into the mouths of Indian children. Out of fad and style quo tient, it made its way in exchange of mere money in pockets of many turning into one of the maj or concerns for health problems particularly in India. Various social workers and he alth professionals have urged for ban of tobacco products, especially the gutka as it is the n eed of the hour to stop chewing to avoid future regret of oral health. In that context, gove rnment too is starting a ban of sale and supply of such products considering the youth in terms of its addiction and child labour associated. However, with the increasing awareness regarding it s pros and cons, alarming many of this fad, it’s slowly and gradually making its way to exit to create smiles with disease and addiction free life to man

  20. Mean exit time and survival probability within the CTRW formalism

    Science.gov (United States)

    Montero, M.; Masoliver, J.

    2007-05-01

    An intense research on financial market microstructure is presently in progress. Continuous time random walks (CTRWs) are general models capable to capture the small-scale properties that high frequency data series show. The use of CTRW models in the analysis of financial problems is quite recent and their potentials have not been fully developed. Here we present two (closely related) applications of great interest in risk control. In the first place, we will review the problem of modelling the behaviour of the mean exit time (MET) of a process out of a given region of fixed size. The surveyed stochastic processes are the cumulative returns of asset prices. The link between the value of the MET and the timescale of the market fluctuations of a certain degree is crystal clear. In this sense, MET value may help, for instance, in deciding the optimal time horizon for the investment. The MET is, however, one among the statistics of a distribution of bigger interest: the survival probability (SP), the likelihood that after some lapse of time a process remains inside the given region without having crossed its boundaries. The final part of the manuscript is devoted to the study of this quantity. Note that the use of SPs may outperform the standard “Value at Risk" (VaR) method for two reasons: we can consider other market dynamics than the limited Wiener process and, even in this case, a risk level derived from the SP will ensure (within the desired quintile) that the quoted value of the portfolio will not leave the safety zone. We present some preliminary theoretical and applied results concerning this topic.

  1. How to make a graceful exit from the merchant function

    International Nuclear Information System (INIS)

    The impact that deregulation and convergence has had on local distribution companies (LDCs) was discussed. LDCs are getting out of a whole range of business activities, or are turning some of them into new entities while transferring others to affiliates. At the other end of the spectrum, Consumers Gas, Canada's largest LDC, has moved from a gas distribution and an oil pipeline company to becoming a total energy provider. The changes at Consumers Gas began with the Halloween agreement which was based on the following four basic principles: (1) better access for Canadian buyers to gas supply, (2) better access for Canadian producers to gas markets, (3) protection for Canadian consumers for reasonable, foreseeable gas requirements, and (4) a commitment to create a competitive natural gas market in Canada. At the same time, several small niche market players have entered the retail market to compete with large producers such as Sunoco and Shell. Ontario also saw the arrival of large marketers such as Enron, and the development of an active direct purchase market. Today, 65 per cent of the volume of natural gas transport is on behalf of direct purchase customers. The next phase of deregulation was also looked at, focusing primarily on the growing problems with the current regulated local distribution companies' gas supply options and the resulting price volatility and uncertainty due to an increase of direct purchase activity. Various possible ways to resolve this problem are explored, including exiting the merchant function, i.e. to change from an obligation to supply gas to an obligation to deliver gas, all the while ensuring that the consumer is protected. Other problems, such as convergence, unbundling and rebundling will also have to be dealt with in the next phase of deregulation

  2. Polycyclic aromatic hydrocarbons with SPICA

    CERN Document Server

    Berne, O; Mulas, G; Tielens, A G G M; Goicoechea, J R

    2009-01-01

    Thanks to high sensitivity and angular resolution and broad spectral coverage, SPICA will offer a unique opportunity to better characterize the nature of polycyclic aromatic hydrocarbons (PAHs) and very small grains (VSGs), to better use them as probes of astrophysical environments. The angular resolution will enable to probe the chemical frontiers in the evolution process from VSGs to neutral PAHs, to ionized PAHs and to "Grand-PAHs" in photodissotiation regions and HII regions, as a function of G$_0$/n (UV radiation field / density). High sensitivity will favor the detection of the far-IR skeletal emission bands of PAHs, which provide specific fingerprints and could lead to the identification of individual PAHs. This overall characterization will allow to use PAH and VSG populations as tracers of physical conditions in spatially resolved protoplanetary disks and nearby galaxies (using mid-IR instruments), and in high redshift galaxies (using the far-IR instrument), thanks to the broad spectral coverage SPIC...

  3. Influences of exit and stair conditions on human evacuation in a dormitory

    Science.gov (United States)

    Lei, Wenjun; Li, Angui; Gao, Ran; Wang, Xiaowei

    2012-12-01

    Evacuation processes of students are investigated by experiment and simulation. The experiment is performed for students evacuating from a dormitory with an exit and stairs. FDS+Evac is proposed to simulate the exit and stair dynamics of occupant evacuation. Concerning the exit and stair widths, we put forward some useful standpoints. Good agreement is achieved between the predicted results and experimental results. With the increase of exit width, a significant stratification phenomenon will be found in flow rate. Stratification phenomenon is that two different stable flow rates will emerge during the evacuation. And the flow rate curve looks like a ladder. The larger the exit width, the earlier the stratification phenomenon appears. When exit width is more than 2.0 m, the flow rate of each exit width is divided into two stable stages, and the evacuation times show almost no change. The judgment that the existence of stairs causes flow stratification is reasonable. By changing the width of the stairs, we proved that judgment. The smaller the width of BC, the earlier the stratification appears. We found that scenario 5 is the most adverse circumstance. Those results are helpful in performance-based design of buildings.

  4. Transgenic C. elegans dauer larvae expressing hookworm phospho null DAF-16/FoxO exit dauer.

    Directory of Open Access Journals (Sweden)

    Verena Gelmedin

    Full Text Available Parasitic hookworms and the free-living model nematode Caenorhabtidis elegans share a developmental arrested stage, called the dauer stage in C. elegans and the infective third-stage larva (L3 in hookworms. One of the key transcription factors that regulate entrance to and exit from developmental arrest is the forkhead transcription factor DAF-16/FoxO. During the dauer stage, DAF-16 is activated and localized in the nucleus. DAF-16 is negatively regulated by phosphorylation by the upstream kinase AKT, which causes DAF-16 to localize out of the nucleus and the worm to exit from dauer. DAF-16 is conserved in hookworms, and hypothesized to control recovery from L3 arrest during infection. Lacking reverse genetic techniques for use in hookworms, we used C. elegans complementation assays to investigate the function of Ancylostoma caninum DAF-16 during entrance and exit from L3 developmental arrest. We performed dauer switching assays and observed the restoration of the dauer phenotype when Ac-DAF-16 was expressed in temperature-sensitive dauer defective C. elegans daf-2(e1370;daf-16(mu86 mutants. AKT phosphorylation site mutants of Ac-DAF-16 were also able to restore the dauer phenotype, but surprisingly allowed dauer exit when temperatures were lowered. We used fluorescence microscopy to localize DAF-16 during dauer and exit from dauer in C. elegans DAF-16 mutant worms expressing Ac-DAF-16, and found that Ac-DAF-16 exited the nucleus during dauer exit. Surprisingly, Ac-DAF-16 with mutated AKT phosphorylation sites also exited the nucleus during dauer exit. Our results suggest that another mechanism may be involved in the regulation DAF-16 nuclear localization during recovery from developmental arrest.

  5. Jet engine nozzle exit configurations, including projections oriented relative to pylons, and associated systems and methods

    Science.gov (United States)

    Mengle, Vinod G. (Inventor); Thomas, Russell H. (Inventor)

    2012-01-01

    Nozzle exit configurations and associated systems and methods are disclosed. An aircraft system in accordance with one embodiment includes a jet engine exhaust nozzle having an internal flow surface and an exit aperture, with the exit aperture having a perimeter that includes multiple projections extending in an aft direction. Aft portions of individual neighboring projections are spaced apart from each other by a gap, and a geometric feature of the multiple can change in a monotonic manner along at least a portion of the perimeter. Projections near a support pylon and/or associated heat shield can have particular configurations, including greater flow immersion than other projections.

  6. Can exit prizes induce lame ducks to shirk less? Experimental evidence

    Directory of Open Access Journals (Sweden)

    Leif Helland

    2012-12-01

    Full Text Available Elected representatives serving their final period face only weak incentives to provide costly effort. However, overlapping generations (OLG models suggest that exit prizes sustained by trigger strategies can induce representatives in their final period to provide such effort. We evaluate this hypothesis using a simple OLG public good experiment, the central treatment being whether exit prizes are permitted. We find that a significantly higher number of subjects in their final period contribute when exit prizes are permitted. However, this result does not originate from use of trigger strategies. More likely explanations include gift-exchange and focal-point effects.

  7. Assessment Drives Learning: The Effect of Central Exit Exams on Curricular Knowledge and Mathematical Literacy

    OpenAIRE

    Jürges, Hendrik; Schneider, Kerstin; Senkbeil, Martin; Claus H. Carstensen

    2009-01-01

    In this paper, we use data from the German PISA 2003 sample to study the effects of central exit examinations on student performance, student attitudes, and teacher behavior. Unlike earlier studies we use (i) a value-added measure to pin down the effect of central exit exams on learning in the last year before the exam and (ii) separate test scores for mathematical literacy and curriculum-based knowledge. The findings indicate that central exit exams only improve curriculum-based knowledge bu...

  8. Market entry and exit by biotech and device companies funded by venture capital.

    Science.gov (United States)

    Burns, Lawton R; Housman, Michael G; Robinson, Charles A

    2009-01-01

    Start-up companies in the biotechnology and medical device sectors are important sources of health care innovation. This paper describes the role of venture capital in supporting these companies and charts the growth in venture capital financial support. The paper then uses longitudinal data to describe market entry and exit by these companies. Similar factors are associated with entry and exit in the two sectors. Entries and exits in one sector also appear to influence entry in the other. These findings have important implications for developing innovative technologies and ensuring competitive markets in the life sciences. PMID:19049998

  9. Oil and detergent pollution on coastal areas of Dardanelles in 1996-1997

    International Nuclear Information System (INIS)

    The oil and detergent pollution was determined in coastal waters and sediments in Dardanelles at entrance, Gelibolu and Lapseki; at exit, Canakkale. The max. level of oil pollution in sea water was 154.76 Mg/L at entrance and 76.30 Mg/L at the exit in 1996; 429.54 Mg/L and 539.10 Mg/L respectively in 1997. In sediments 51.13 Mg/g at the entrance and 338.76 Mg/L at the exit in 1996 and 369.56 Mg/L and 339.56 in 1997. In detergent pollution the max. level was 50.51 Mg/L at the entrance and 61.84 at the exit in 1996 and 80.08 Mg/L and 61.43 in 1997. The findings indicated that the coastal areas were more polluted than mid-points (shipping route) of Dardanelles and also Sea of Marmara in 1996

  10. Alkyl polycyclic aromatic hydrocarbons emissions in diesel/biodiesel exhaust

    Science.gov (United States)

    Casal, Carina S.; Arbilla, Graciela; Corrêa, Sergio M.

    2014-10-01

    Polycyclic aromatic hydrocarbons (PAHs) are widely studied in environmental matrices, such as air, water, soil and sediment, because of their toxicity, mutagenicity and carcinogenicity. Because of these properties, the environmental agencies of developed countries have listed sixteen PAHs as priority pollutants. Few countries have limits for these compounds for ambient air, but they only limit emissions from stationary and mobile sources and occupational areas. There are several studies to specifically address the 16 priority PAHs and very little for the alkyl PAHs. These compounds are more abundant, more persistent and frequently more toxic than the non-alkylated PAHs, and the toxicity increases with the number of alkyl substitutions on the aromatic ring. In this study, a method was developed for the analysis of PAHs and alkyl PAHs by using a GC-MS and large injection volume injection coupled with program temperature vaporisation, which allows for limits of detection below 1.0 ng μL-1. Several variables were tested, such as the injection volume, injection velocity, injector initial temperature, duration of the solvent split and others. This method was evaluated in samples from particulate matter from the emissions of engines employing standard diesel, commercial diesel and biodiesel B20. Samples were collected on a dynamometer bench for a diesel engine cycle and the results ranged from 0.5 to 96.9 ng mL-1, indicating that diesel/biodiesel makes a significant contribution to the formation of PAHs and alkyl PAHs.

  11. Direct photolysis of polycyclic aromatic hydrocarbons in drinking water sources

    International Nuclear Information System (INIS)

    Highlights: → Low pressure UV photolysis can be used by drinking water utilities to degrade PAHs. → Real water matrices with different compositions were tested. → Photolysis kinetic parameters and by-product formation are described. → The formation of photolysis by-products is highly dependent on the source waters. - Abstract: The widely used low pressure lamps were tested in terms of their efficiency to degrade polycyclic aromatic hydrocarbons listed as priority pollutants by the European Water Framework Directive and the U.S. Environmental Protection Agency, in water matrices with very different compositions (laboratory grade water, groundwater, and surface water). Using a UV fluence of 1500 mJ/cm2, anthracene and benzo(a)pyrene were efficiently degraded, with much higher percent removals obtained when present in groundwater (83-93%) compared to surface water (36-48%). The removal percentages obtained for fluoranthene were lower and ranged from 13 to 54% in the different water matrices tested. Several parameters that influence the direct photolysis of polycyclic aromatic hydrocarbons were determined and their photolysis by-products were identified by mass spectrometry. The formation of photolysis by-products was found to be highly dependent on the source waters tested.

  12. Sorption of polycyclic aromatic hydrocarbons on particulate organic matters

    International Nuclear Information System (INIS)

    Particulate organic matter (POM) is a key organic matter fraction which can influence soil fertility. Its interactions with hydrophobic organic pollutants (HOCs) have not been characterized and the mechanisms of retention of HOCs by POM remain unclear. In the present study, sorption behaviors of polycyclic aromatic hydrocarbons (PAHs) naphthalene (NAP), phenanthrene (PHE), and pyrene (PYR) by POMs separated from different soils were examined and the POMs were characterized by elemental analysis, solid state 13C NMR, and Fourier transform infrared spectroscopy (FT-IR). The results indicated that POMs were mainly composed of aliphatic components with high polarity. The different original POMs showed similar chemical composition and configuration. Sorption behaviors of PAHs indicated that there was no significant difference in sorption capacity among the POMs. Sorption of NAP and PHE by POMs displayed a nonlinear isotherm, while sorption of PYR yielded a linear isotherm. No significant hysteresis and ionic strength effect were observed for PAH desorption from the POMs.

  13. Biosurfactant-enhanced bioremediation of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Cameotra, S.S.; Bollag, J.M. [Penn State University, University Park, PA (USA). Soil Biochemical Lab.

    2003-07-01

    Biosurfactants are surface-active compounds synthesized by it wide variety of micro-organisms. They are molecules that have both hydrophobic and hydrophilic domains and are capable of lowering the surface tension and the interfacial tension of the growth medium. Biosurfactants possess different chemical structures - lipopeptides, glycolipids, neutral lipids, and fatty acids. They are nontoxic biomolecules that are biodegradable. Biosurfactants also exhibit strong emulsification of hydrophobic compounds and form stable emulsions. Polycyclic aromatic hydrocarbons (PAHs) can be toxic, mutagenic, and carcinogenic compounds that pollute the environment. They are released to the environment its a result of spillage of oil and byproducts of coal treatment processes. The low water solubility of PAHs limits their availability to microorganisms, which is a potential problem for bioremediation of PAH-contaminated sites. Microbially produced surfactants enhance the bioavailability of these hydrophobic compounds for bioremediation. Therefore, biosurfactant-enhanced solubility of PAHs has potential applications in bioremediation.

  14. [Polycyclic aromatic hydrocarbons (PAH) in cereal breakfast products].

    Science.gov (United States)

    Ciemniak, Artur; Chrachol, Lucyna

    2008-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants formed by incomplete combustion (pyrolysis) of several organic materials. PAHs occur as complex mixtures, never as individual components. They are chemically stable and highly lipophilic in nature and occur as contaminants in different food categories: vegetables, fruit, cereals, oils and fats, especially barbecued and smoked food. The present study was carried out to determine 16 PAHs in cereal products: musli, corn, oats and barley flakes, and crunchy. The analytical procedure was based on alkaline digestion, extraction with n-hexane and cleaned up in a florisil cartridge. Chromatographic separation was performed using gas chromatography (HP 6890) coupled to mass spectrometry (HP 5973). The levels of PAHs in most samples were generally low and excepting one sample of bred varied between 4.2 to 169 microg/kg. Benzo[a]pyrene, was detected in all samples, at level 0.02 microg/kg to 16 microg/kg. PMID:19143427

  15. Translation of an aromatic field image

    Science.gov (United States)

    Yastrebov, Anatoliy S.; Makarov, Leonid M.; Protasenya, Sergey V.; Vereshak, Evgeniy V.

    2005-04-01

    As is known, for a person there are possibilities of perception of audio, video, and aromatic information messages by means of touch systems available to him. Such packages of the messages are accepted remotely without direct contact to a message source. Now the direction bound with creation of devices capable to playback aromatic information images is actively developed. Such systems switched on in special transmission channels of information provide adequate perception of information highways describing actual event which happen in the enclosing world. One can present the aromatic-field image through a series of control codes for an aromatic field synthesizer, thereupon it is possible to transmit the image on telecommunication networks. For odor oscillators installation problems in compartments of automobiles, buses as well as of airplanes are widely discussed. In this work we deal with a device for synthesis of an image of an aromatic field which works under the control of a personal computer with an express program. In the given operation, the possibility of remote handle of an image of an aromatic field and, as a corollary, organization of a new tansmission channel for the information on the aromatic-field image through an existing synthesizer is considered.

  16. Organ nic pollutants in underground water

    International Nuclear Information System (INIS)

    Many organic compounds have been diagnosed in underground and surface waters, and there are many theories that explain the source of the dangerous materials on Punic health. The source of pollution could be the underground stored fuel or the polluted water in farms saturated with agricultural insecticides and chemical fertilizers, or there could be leaks in sewage water wastes. The source of pollution could also be the water surfaces in the areas of garbage disposal or industrial and home waste discharge. Due to the fact that the underground water is separated from oxygen in the air, its ability on self-purification is very low, in that the micro-organism that will do the dismantling and decomposition of the organic materials that pollute the water are in need for oxygen. In the event that underground water is subject to pollution m there are many methods for t resting the polluted water including the chemical decomposition method by injecting the polluted areas with neutralizing or oxidizing chemicals, such as Ozone, Chlorine or Hydrogen Peroxide. The mechanical methods could be used for getting rid of the volatile organic materials. As to biological decomposition, it is done with the use of bacteria in dismantling the poisonous materials into un poisonous materials. The preliminary analysis of water samples in one of the water wells in Sar ir and Tazarbo in Great Jamahirieh indicated that the concentration of total organic compounds (TOC) exceeded the internationally allowed limits. This indicates a deterioration of quality of some of underground water resources. It is well known that some of the organic pollutants have a great role in causing dangerous diseases, such as the polynuclear aromatic hydrocarbons and some halogenated compounds that cause cancer. Therefore, much research is required in this field for diagnosing the polluting organic compounds and determining the suitability of this water for drinking or for human consumption. (author). 21 refs., 6 figs

  17. Indoor Air Pollution (Environmental Health Student Portal)

    Science.gov (United States)

    ... Students to Environmental Health Information Menu Home Air Pollution Air Pollution Home Indoor Air Pollution Outdoor Air Pollution ... Pollution Indoor Air Pollution Print this Page Air Pollution Air Pollution Home Indoor Air Pollution Outdoor Air Pollution ...

  18. Development of new entrance/exit processing system using EPD (electronic personal dosimeter) with ID card reader

    International Nuclear Information System (INIS)

    Entrance/exit processing system in Shika Nuclear Power Station, Hokuriku Electric Power Company was upgraded in May 2004. In this new system, dosimeters with built-in ID card reading are used and make entrance/exit processing time shorter. Hereinafter describes this new dosimeters and entrance/exit management system. (author)

  19. Conservation of medicinal and aromatic plants

    Directory of Open Access Journals (Sweden)

    Šveistytė, Laima

    2016-07-01

    Full Text Available The conservation of medicinal and aromatic plants includes ex situ and in situ methods. The genetic recourses of medicinal and aromatic plants are stored, studied and constantly maintained in the field collections of the Institute of Botany of Nature Research Centre, Kaunas Botanical Garden of Vytautas Magnus University and Aleksandras Stulginskis University of Agriculture. Presently seeds of 214 accessions representing 38 species of medicinal and aromatic plants are stored in a long-term storage in the Plant Gene Bank. The data about national genetic resources are collected and stored in the Central Database of the Plant Gene Bank.

  20. Aromaticity influencing the thermostability of micellar dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J.A.; Kunzman, W.J.

    1970-02-17

    The thermostability of a micellar dispersion is shifted to higher temperature ranges by increasing the aromaticity of the hydrocarbon within the dispersion. The micellar solution is composed of kerosene and light catalytic cycle oil (hydrocarbons), water, sodium or ammonium alkyl aryl naphthenic sulfonates (petroleum sulfonate surfactant), isopropanol (cosurfactant), and sodium sulfate (electrolyte). The aromatic content of the light catalytic cycle oil is higher than the aromatic content of the kerosene. By increasing the concentration of cycle oil to kerosene, stable micellar solutions at temperatures from ambient to 200/sup 0/F can be obtained. The aqueous medium can be soft, brackish, or a brine.

  1. Hexacoordinate bonding and aromaticity in silicon phthalocyanine.

    Science.gov (United States)

    Yang, Yang

    2010-12-23

    Si-E bondings in hexacoordinate silicon phthalocyanine were analyzed using bond order (BO), energy partition, atoms in molecules (AIM), electron localization function (ELF), and localized orbital locator (LOL). Bond models were proposed to explain differences between hexacoordinate and tetracoordinate Si-E bondings. Aromaticity of silicon phthalocyanine was investigated using nucleus-independent chemical shift (NICS), harmonic oscillator model of aromaticity (HOMA), conceptual density functional theory (DFT), ring critical point (RCP) descriptors, and delocalization index (DI). Structure, energy, bonding, and aromaticity of tetracoordinate silicon phthalocyanine were studied and compared with hexacoordinate one. PMID:21105726

  2. Quantitative assessment of exposure and risk for three carcinogenics in long-standing pollution sites

    International Nuclear Information System (INIS)

    The project attempts a quantitative assessment of risks for three carcinogenics that are common in sites of long-standing pollution. Benzo(a)pyrene stands for the group of polycyclic aromatic hydrocarbons, cadmium for heavy metals, and benzene for volatile aromatic compounds. The report discusses the general fundamentals of exposure and risk assessment. The exposure model is described in detail and applied to the three test substances. (orig./MG)

  3. Ovarian cancer mortality and industrial pollution

    International Nuclear Information System (INIS)

    We investigated whether there might be excess ovarian cancer mortality among women residing near Spanish industries, according to different categories of industrial groups and toxic substances. An ecologic study was designed to examine ovarian cancer mortality at a municipal level (period 1997–2006). Population exposure to pollution was estimated by means of distance from town to facility. Using Poisson regression models, we assessed the relative risk of dying from ovarian cancer in zones around installations, and analyzed the effect of industrial groups and pollutant substances. Excess ovarian cancer mortality was detected in the vicinity of all sectors combined, and, principally, near refineries, fertilizers plants, glass production, paper production, food/beverage sector, waste treatment plants, pharmaceutical industry and ceramic. Insofar as substances were concerned, statistically significant associations were observed for installations releasing metals and polycyclic aromatic chemicals. These results support that residing near industries could be a risk factor for ovarian cancer mortality. - Highlights: • We studied excess mortality due to ovarian cancer near Spanish industries. • Integrated nested Laplace approximations were used as a Bayesian inference tool. • We found excess ovarian cancer mortality near all industrial groups as a whole. • Risk also was found in towns near industries releasing carcinogens and metals. • Risk was associated with plants releasing polycyclic aromatic chemicals and POPs. - Our results support that residing in the vicinity of pollutant industries could be a risk factor for ovarian cancer mortality

  4. Metagenomics for the discovery of pollutant degrading enzymes.

    Science.gov (United States)

    Ufarté, Lisa; Laville, Élisabeth; Duquesne, Sophie; Potocki-Veronese, Gabrielle

    2015-12-01

    Organic pollutants, including xenobiotics, are often persistent and toxic organic compounds resulting from human activities and released in large amounts into terrestrial, fluvial and marine environments. However, some microbial species which are naturally exposed to these compounds in their own habitat are capable of degrading a large range of pollutants, especially poly-aromatic, halogenated and polyester molecules. These microbes constitute a huge reservoir of enzymes for the diagnosis of pollution and for bioremediation. Most are found in highly complex ecosystems like soils, activated sludge, compost or polluted water, and more than 99% have never been cultured. Meta-omic approaches are thus well suited to retrieve biocatalysts from these environmental samples. In this review, we report the latest advances in functional metagenomics aimed at the discovery of enzymes capable of acting on different kinds of polluting molecules. PMID:26526541

  5. Emission of toxic air pollutants from biomass combustion

    International Nuclear Information System (INIS)

    Combustion of biomass for power generation, home heating, process steam generation, and waste disposal constitutes a major source of air pollutants nationwide. Emissions from hog-fueled boilers, demolition wood-fired power plants, municipal waste incinerators, woodstoves, fireplaces, pellet stoves, agricultural burning, and forestry burning have been characterized for a variety of purposes. These have included risk assessment, permitting, emission inventory development, source profiling for receptor modeling, and control technology evaluations. From the results of the source characterization studies a compilation of emission factors for criteria and non-criteria pollutants are presented here. Key among these pollutants are polycyclic aromatic hydrocarbons, priority pollutant metals, carbon monoxide, sulfur dioxide, nitrous oxides, and PM10 particles. The emission factors from the biomass combustion processes are compared and contrasted with other pollutant sources. In addition, sampling and analysis procedures most appropriate for characterizing emissions from the biomass combustion sources are also discussed

  6. Optimum design of exit guide vane on the bidirectional tubular turbine

    International Nuclear Information System (INIS)

    Performance prediction about the forward generation condition based on a bidirectional through-flow turbine runner was conducted. The model characteristic curves and efficiency curve under reverse generation condition were plotted. In order to improve the reverse performance, exit guide vanes were lied behind the runner, the forward and reverse operating performance about a runner lied post-guide vane were numerically simulated. The results shows that the flow field distribution on forward generation condition did not significantly change after exit guide vanes were lied, and the energy conversion efficiency decreased. After exit guide vanes were lied, flow pattern of runner intake on under reverse generation condition were bettered, and the energy conversion efficiency increased. This study confirms that the exit guide vanes can improve the hydraulic performance of the turbine on reverse generation condition in view of numerical simulation

  7. Quantitative Analysis of Zero and High Order Laue Zones Effects on the Exit Wave Function

    Institute of Scientific and Technical Information of China (English)

    Canying CAI; Qibin YANG; Hongrong LIU; Yanguo WANG

    2004-01-01

    The exit wave function including zero and high order Laue zones has been simulated by both multi-slice method and electron dynamic diffraction analytical expression. Coincidence of the simulations by these two methods was achieved. The calculated results showed that the exit wave function highly dominated by zero order Laue zone,while high order ones modify the exit wave function to some extent depending on the situation. High order Laue zone effects become important for the following cases: sample consists of light elements, the thickness is very thin,lattice planar spacing perpendicular to the direction of the incident beam is large, and the electron beam has long wavelength. In these cases the exit wave function should be corrected by adding high order Laue zone effects. The analytical expression is effective and convenient for dealing with high order Laue zone effects.

  8. MTV EXIT CAMPAIGN-How can it be made more effective in Denmark?

    OpenAIRE

    Mizzi, Antonella; Hansen, Cassandra Britt

    2007-01-01

    In this project we examine an MTV campaign with the name of MTV EXIT and through our research we try to find out how can it be made more effective in making a difference in handling human trafficking in Denmark.

  9. Pulse shape discrimination in non-aromatic plastics

    International Nuclear Information System (INIS)

    Recently it has been demonstrated that plastic scintillators have the ability to distinguish neutrons from gamma rays by way of pulse shape discrimination (PSD). This discovery has lead to new materials and new capabilities. Here we report our work with the effects of aromatic, non-aromatic, and mixed aromatic/non-aromatic matrices have on the performance of PSD plastic scintillators

  10. Do High School Exit Exams Influence Educational Attainment or Labor Market Performance?

    OpenAIRE

    Thomas S. Dee; Brian A. Jacob

    2006-01-01

    State requirements that high school graduates pass exit exams were the leading edge of the movement towards standards-based reform and continue to be adopted and refined by states today. In this study, we present new empirical evidence on how exit exams influenced educational attainment and labor market experiences using data from the 2000 Census and the National Center for Education Statistics' Common Core of Data (CCD). Our results suggest that the effects of these reforms have been heterog...

  11. Exit-beskatning af selskaber og det EU-retlige proportionalitetsprincip

    DEFF Research Database (Denmark)

    Poulsen, Martin

    2011-01-01

    EU-Domstolen har afsagt dom i den nederlandske sag National Grid Indus om exit-beskatning af selskaber. Dommen må forventes at medføre, at en række lande, herunder Danmark, vil være forpligtet til at ændre nugældende regler om exit-beskatning. Artiklen foretager i den forbindelse en analyse af de...

  12. The Effect of Central Exit Examinations on Student Achievement: Quasi-experimental Evidence from TIMSS Germany

    OpenAIRE

    Jürges, Hendrik; Schneider, Kerstin; Büchel, Felix

    2003-01-01

    This paper makes use of the regional variation in schooling legislation within the German secondary education system to estimate the causal effect of central exit examinations on student performance. We propose a difference-in-differences framework that exploits the quasi-experimental nature of the German TIMSS middle-school sample. The estimates show that students in federal states with central exit examinations clearly outperform students in other federal states, but that only part of the d...

  13. Modeling Exit and Entry of Farmers in a Crop Insurance Program

    OpenAIRE

    Cabas, Juan H.; Leiva, Akssell J.; Weersink, Alfons

    2008-01-01

    This paper examines the factors influencing farmer participation in crop insurance schemes, but unlike previous studies that focus on total demand, participation is disaggregated into entrants and those exiting. Modeling entry and exit decisions separately illustrates that the effect of a given variable is often muted by aggregation. In addition, the approach in this paper distinguishes between price and yield variables rather than total returns and is consequently able to demonstrate that pr...

  14. Transnational migration and political articulation : making new sense of 'exit and voice'

    OpenAIRE

    Hoffmann, Bert

    2008-01-01

    "Albert O. Hirschman's scheme of 'exit and voice', long a classic in the study of migration and its political implications, was conceived within the framework of 'methodological nationalism'. However, the rise of migrant transnationalism is eroding the distinction between domestic and foreign actors on which the postulate was based, that exit meant renouncing on voice. Combining theoretical considerations with empirical insights from Latin American migration, this paper calls for a critical r...

  15. They Walk Among Us: Sex Work Exiting, Re-entry and Duality

    OpenAIRE

    Bowen, Raven R.

    2013-01-01

    This examination of sex work exit, re-entry, and duality includes the thoughts, experiences, and factors that individuals identify as having influenced their decisions about sex industry involvement. Utilizing literature on sex work exit from around the world, and using a blend of theoretical frameworks which include constructionist intersectionality, symbolic interactionism, and concepts of “capital,” “field,” and “habitus”, the decision-making processes of the 22 participants who contribut...

  16. Research onidentify stadia of interchange exit ramp in mountainous urban freeway

    Directory of Open Access Journals (Sweden)

    TAN Hai

    2015-08-01

    Full Text Available Theidentify stadia of interchange exit ramp hasgreat influence on capacity and safety levels of urbanexpressway,combining with car psychological theory and driverscharacteristics,based on design speed and driver's reaction time, driversoperating characteristics and the cause of the accident on interchange exit ramp was analyzed and the identify stadia threshold under different design speedwas determined. The resultindicates that: the requirements of specification for identify stadia has some limitations, it should be modified appropriately.

  17. Can exit prizes induce lame ducks to shirk less? Experimental evidence

    OpenAIRE

    Leif Helland; Jon Hovi; Lars Monkerud

    2012-01-01

    Elected representatives serving their final period face only weak incentives to provide costly effort. However, overlapping generations (OLG) models suggest that exit prizes sustained by trigger strategies can induce representatives in their final period to provide such effort. We evaluate this hypothesis using a simple OLG public good experiment, the central treatment being whether exit prizes are permitted. We find that a significantly higher number of subjects in their final...

  18. Exit and Failure of Credit Unions in Brazil: A Risk Analysis

    OpenAIRE

    Flávio Leonel de Carvalho; Maria Dolores Montoya Diaz; Sigismundo Bialoskorski Neto; Aquiles Elie Guimarães Kalatzis

    2015-01-01

    This study aims to investigate the factors that affect the market exit of Brazilian singular credit unions from 1995 to 2009; it also identifies and lists the determinants of various types of market exits and analyzes whether profitability is a significant factor for credit union survival. This study was conducted with accounting data provided by the Central Bank of Brazil, which derives only from individual cooperatives, i.e. singular credit unions. Quarterly financial statements from these ...

  19. Watch Out for Potholes on the Exit Ramp! Experiences from the IFC Against AIDS Program

    OpenAIRE

    Mhuriyengwe, Lovemore

    2010-01-01

    No program or product can be expected to go on forever, but the timing and manner in which International Finance Corporation (IFC) executes an exit can make a tremendous difference to clients, staff, and the Corporation's reputation. This smart lesson draws on the experience of the IFC against AIDS team after IFC advisory services decided to exit from the HIV/AIDS space in February 2009. I...

  20. Volatilisation of aromatic hydrocarbons from soil

    DEFF Research Database (Denmark)

    Lindhardt, B.; Christensen, T.H.

    1996-01-01

    The non-steady-state fluxes of aromatic hydrocarbons were measured in the laboratory from the surface of soils contaminated with coal tar Four soil samples from a former gasworks site were used for the experiments. The fluxes were quantified for 11 selected compounds, 4 mono- and 7 polycyclic...... aromatic hydrocarbons, for a period of up to 8 or 16 days. The concentrations of the selected compounds in the soils were between 0.2 and 3,100 mu g/g. The study included the experimental determination of the distribution coefficient of the aromatic hydrocarbons between the sorbed phase and the water under...... saturated conditions. The determined distribution coefficients showed that the aromatic hydrocarbons were more strongly sorbed to the total organic carbon including the coal tar pitch - by a factor of 8 to 25 - than expected for natural organic matter. The fluxes were also estimated using an analytical...

  1. Graphite Oxide and Aromatic Amines : Size Matters

    NARCIS (Netherlands)

    Spyrou, Konstantinos; Calvaresi, Matteo; Diamanti, Evmorfi A. K.; Tsoufis, Theodoros; Gournis, Dimitrios; Rudolf, Petra; Zerbetto, Francesco

    2015-01-01

    Experimental and theoretical studies are performed in order to illuminate, for first time, the intercalation mechanism of polycyclic aromatic molecules into graphite oxide. Two representative molecules of this family, aniline and naphthalene amine are investigated. After intercalation, aniline molec

  2. International congress on aromatic and medicinal plants

    International Nuclear Information System (INIS)

    Full Text : In Morocco, medicinal and aromatic plants occupy an important place in the traditional care system of a large number of local people. They are also economically strong potential, but unfortunately they are not valued enough. Indeed, Morocco by its privileged geographical position in the Mediterranean basin and its floristic diversity (with a total of over 4,200 species and subspecies of which over 500 are recognized as medicinal and aromatic plants), is a leading provider of traditional global market. In this context and given the back label of the natural global, group research and studies on Aromatic and Medicinal Plants (GREPAM), the Faculty of Semlalia and University Cadi Ayyad, organize: the International Congress on Medicinal and Aromatic Plants CIPAM 2009. The organization of this conference is part of scientific research developed by the GREPAM.

  3. Activity relationships for aromatic crown ethers

    CERN Document Server

    Wilson, M J

    1998-01-01

    This thesis involves an investigation of aromatic crown ethers and a study of their binding constants for alkali metals. The study was motivated by the current needs of the semiconductor industry to improve the scavenging of mobile ions from fabricated circuits. A number of aromatic crown ethers have been sulphonated in an attempt to improve their water solubility and cation binding activity. These materials have been extensively studied and their binding activity determined. In collaboration with a molecular modelling study, the effect of ionisable sulphonate groups on the macrocycles' behaviour has been investigated. The broader issue of the effect of substituents in aromatic crown ethers has also been studied with the preparation of a wide range of substituted crown ethers. The cation binding activity of these materials has been found to bear a simple relationship to the electron withdrawing nature of the aromatic substituents. This relationship can be accurately monitored using electronic charge densities...

  4. Comments on Coulomb pairing in aromatic hydrocarbons

    CERN Document Server

    Huber, D L

    2013-01-01

    Recently reported anomalies in the double-photonionization spectra of aromatic molecules such as benzene, naphthalene, anthracene and coronene are attributed to Coulomb-pair resonances of pi electrons.

  5. PROTONATED POLYCYCLIC AROMATIC HYDROCARBONS REVISITED

    International Nuclear Information System (INIS)

    We reconsider the contribution that singly protonated polycyclic aromatic hydrocarbons (PAHs; HPAH+s) might make to the Class A component of the 6.2 μm interstellar emission feature in light of the recent experimental measurements of protonated naphthalene and coronene. Our calculations on the small HPAH+s have a band near 6.2 μm, as found in experiment. While the larger HPAH+s still have emission near 6.2 μm, the much larger intensity of the band near 6.3 μm overwhelms the weaker band at 6.2 μm, so that the 6.2 μm band is barely visible. Since the large PAHs are more representative of those in the interstellar medium, our work suggests that large HPAH+s cannot be major contributors to the observed emission at 6.2 μm (i.e., Class A species). Saturating large PAH cations with hydrogen atoms retains the 6.2 μm Class A band position, but the rest of the spectrum is inconsistent with observed spectra.

  6. Dehydrogenative Aromatization of Saturated Aromatic Compounds by Graphite Oxide and Molecular Sieves

    Institute of Scientific and Technical Information of China (English)

    张轩; 徐亮; 王希涛; 马宁; 孙菲菲

    2012-01-01

    Graphite oxide (GO) has attracted much attention of material and catalysis chemists recently. Here we describe a combination of GO and molecular sieves for the dehydrogenative aromatization. GO prepared through improved Hummers method showed high oxidative activity in this reaction. Partially or fully saturated aromatic compounds were converted to their corresponding dehydrogenated aromatic products with fair to excellent conversions and selectivities. As both GO and molecular sieves are easily available, cheap, lowly toxic and have good tolerance to various functional groups, this reaction provides a facile approach toward aromatic compounds from their saturated precursors

  7. Experiment of cavitation erosion at the exit of a long orifice

    International Nuclear Information System (INIS)

    We performed experiments to clarify mechanism of cavitation erosion and to predict cavitation erosion rate at the exit of a long orifice equipped at the chemical and volume control system in a pressurized water reactor (PWR). In order to find this mechanism, we used a high speed video camera. As the result, we observed bubble collapses near the exit of the orifice when flow condition was oscillating. So the bubble collapses due to the oscillation might cause the first stage erosion at the exit of the orifice. Using the orifice which had the cone-shaped exit, we observed that bubbles collapsed near the exit and then they collapsed at the upstream like a chain reaction. So this bubble collapse mechanism could be explained as follows: shock wave was generated by the bubble collapse near the exit, then it propagated upwards, consequently it caused the bubble collapse at the upstream. And we predicted erosion rate by evaluating the effect of the velocity and comparing the erosion resistance between the test speciment (aluminum) and the plant material (stainless steel) by means of vibratory tests. We compared the predicted erosion rate with that of the average value estimated from plant investigation, then we examined the applicability of these method to the plant evaluations. (author)

  8. CFD simulation of smooth and T-abrupt exits in circulating fluidized bed risers

    Institute of Scientific and Technical Information of China (English)

    Xuezhi Wu; Fan Jiang; Xiang Xu; Yunhan Xiao

    2010-01-01

    Gas-solid flow in circulating fluidized bed(CFB)risers depends not only on operating conditions but also on exit configurations.Few studies investigated the effects of exit configurations on flow structure using computational fluid dynamics(CFD).This paper provides a 2D two-fluid model to simulate a cold bench-scale square cross-section riser with smooth and T-abrupt exits.The drag force between the gas and solid phases plays an important role in CFD.Since the drag force model based on homogeneous twophase flow,such as the Wen-Yu correlation,could not capture the heterogeneous structures in gas-solid flow,the structure-dependent energy-minimization multi-scale(EMMS)drag force model(Wang.Ge,&Li,2008),applicable for Geldart B particles(sand),was integrated into the two-fluid model.The calculated axial solids hold-up profiles were respectively exponential curve for smooth exit and C-shaped curve for T-abrupt exit,both consistent with experimental data.This study once again proves the key role of drag force in CFD simulation and also shows the validity of CFD simulation(two-fluid model)to describe exit effects on gas-solid flow in CFB risers.

  9. IR signature study of aircraft engine for variation in nozzle exit area

    Science.gov (United States)

    Baranwal, Nidhi; Mahulikar, Shripad P.

    2016-01-01

    In general, jet engines operate with choked nozzle during take-off, climb and cruise, whereas unchoking occurs while landing and taxiing (when engine is not running at full power). Appropriate thrust in an aircraft in all stages of the flight, i.e., take-off, climb, cruise, descent and landing is achieved through variation in the nozzle exit area. This paper describes the effect on thrust and IR radiance of a turbojet engine due to variation in the exit area of a just choked converging nozzle (Me = 1). The variations in the nozzle exit area result in either choking or unchoking of a just choked converging nozzle. Results for the change in nozzle exit area are analyzed in terms of thrust, mass flow rate and specific fuel consumption. The solid angle subtended (Ω) by the exhaust system is estimated analytically, for the variation in nozzle exit area (Ane), as it affects the visibility of the hot engine parts from the rear aspect. For constant design point thrust, IR radiance is studied from the boresight (ϕ = 0°, directly from the rear side) for various percentage changes in nozzle exit area (%ΔAne), in the 1.9-2.9 μm and 3-5 μm bands.

  10. Optimizing design for the maze exit of a 10-MeV electron irradiation accelerator

    International Nuclear Information System (INIS)

    Background: Irradiation accelerator is being used more and more widely, but the optimizing of radiation shielding is always a problem to be solved. Purpose: To make the dose rates of the maze exit lower and the cost to achieve it less, it is of great significance to design a shielding which is cheap and effective. Methods: The radiation dose rates at different maze exits of a 10-MeV industrial electron linear accelerator were compared by formula and Monte Carlo (Fluka) method. A real-time measurement system composed of Mini Digital Data Logging (Mini-DDL) and Gamma detectors was also used. Results: With one comer added to the exit, another scattering would be generated. The dose rate of exit before changing was 3-4 μGy·h-1 while it was 200 nGy·h-1 after that. Conclusion: The radiation dose rate at the exit will be reduced by one order of magnitude because of another scattering generated by the added turn to the maze exit. All of these do not increase any additional cost and conform to the ALARA (as low as reasonably achievable) principle. It provides a good reference for the future design of shielding for industrial electron linear accelerator. (authors)

  11. Aromatic amines sources, environmental impact and remediation

    OpenAIRE

    Pereira, Luciana; Mondal, P. K.; Alves, M. M.

    2015-01-01

    Aromatic amines are widely used industrial chemicals as their major sources in the environment include several chemical industry sectors such as oil refining, synthetic polymers, dyes, adhesives, rubbers, perfume, pharmaceuticals, pesticides and explosives. They result also from diesel exhaust, combustion of wood chips and rubber and tobacco smoke. Some types of aromatic amines are generated during cooking, special grilled meat and fish, as well. The intensive use and production of these comp...

  12. Aromaticity influencing the thermostability of micellar dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J.A.; Kunzman, W.J.

    1971-05-11

    A hydrocarbon, having sufficient aromaticity to obtain a stable micellar dispersion at the temperature of the formation, is mixed with a surfactant and aqueous medium for injection into the formation to recover crude oil. Higher reservoir temperatures require a greater degree of aromaticity in the hydrocarbon component of the micellar dispersion. This patent is a continuation of U.S. Patent Number 3,495,660 (item No. 118).

  13. Nonchemical weeding of medicinal and aromatic plants

    OpenAIRE

    Carrubba, Alessandra; Militello, Marcello

    2013-01-01

    Medicinal and aromatic plants are major crops of domestic and industrial interest. Medicinal and aromatic plants are increasingly organically grown to enhance profitability. However, the presence of weeds may lead to a decrease in both yield and quality. Therefore, nonchemical methods of weed control are needed. In this study, mechanical weeding, flaming, stale seedbed, and biodegradable mulch were tested from 2003/2004 to 2006/2007 on coriander, fennel, and psyllium. Biomass and seed yield w...

  14. Chemotaxis of Azospirillum Species to Aromatic Compounds

    OpenAIRE

    Lopez-de-Victoria, Geralyne; Lovell, Charles R.

    1993-01-01

    Chemotaxis of Azospirillum lipoferum Sp 59b and Azospirillum brasilense Sp 7 and Sp CD to malate and to the aromatic substrates benzoate, protocatechuate, 4-hydroxybenzoate, and catechol was assayed by the capillary method and direct cell counts. A. lipoferum required induction by growth on 4-hydroxybenzoate for positive chemotaxis to this compound. Chemotaxis of Azospirillum spp. to all other substrates did not require induction. Maximum chemotactic responses for most aromatic compounds occu...

  15. Polynuclear aromatic hydrocarbons for fullerene synthesis in flames

    Science.gov (United States)

    Alford, J. Michael; Diener, Michael D.

    2006-12-19

    This invention provides improved methods for combustion synthesis of carbon nanomaterials, including fullerenes, employing multiple-ring aromatic hydrocarbon fuels selected for high carbon conversion to extractable fullerenes. The multiple-ring aromatic hydrocarbon fuels include those that contain polynuclear aromatic hydrocarbons. More specifically, multiple-ring aromatic hydrocarbon fuels contain a substantial amount of indene, methylnapthalenes or mixtures thereof. Coal tar and petroleum distillate fractions provide low cost hydrocarbon fuels containing polynuclear aromatic hydrocarbons, including without limitation, indene, methylnapthalenes or mixtures thereof.

  16. Formation of Polycyclic Aromatic Hydrocarbons and Nitrogen Containing Polycyclic Aromatic Compounds in Titan's Atmosphere, the Interstellar Medium and Combustion

    Science.gov (United States)

    Landera, Alexander

    2013-12-01

    Several different mechanisms leading to the formation of (substituted) naphthalene and azanaphthalenes were examined using theoretical quantum chemical calculations. As a result, a series of novel synthetic routes to Polycyclic Aromatic Hydrocarbons (PAHs) and Nitrogen Containing Polycyclic Aromatic Compounds (N-PACs) have been proposed. On Earth, these aromatic compounds originate from incomplete combustion and are released into our environment, where they are known to be major pollutants, often with carcinogenic properties. In the atmosphere of a Saturn's moon Titan, these PAH and N-PACs are believed to play a critical role in organic haze formation, as well as acting as chemical precursors to biologically relevant molecules. The theoretical calculations were performed by employing the ab initio G3(MP2,CC)/B3LYP/6-311G** method to effectively probe the Potential Energy Surfaces (PES) relevant to the PAH and N-PAC formation. Following the construction of the PES, Rice-Ramsperger-Kassel-Markus (RRKM) theory was used to evaluate all unimolecular rate constants as a function of collision energy under single-collision conditions. Branching ratios were then evaluated by solving phenomenological rate expressions for the various product concentrations. The most viable pathways to PAH and N-PAC formation were found to be those where the initial attack by the ethynyl (C2H) or cyano (CN) radical toward a unsaturated hydrocarbon molecule led to the formation of an intermediate which could not effectively lose a hydrogen atom. It is not until ring cyclization has occurred, that hydrogen elimination leads to a closed shell product. By quenching the possibility of the initial hydrogen atom elimination, one of the most competitive processes preventing the PAH or N-PAC formation was avoided, and the PAH or N-PAC formation was allowed to proceed. It is concluded that these considerations should be taken into account when attempting to explore any other potential routes towards

  17. River and Stream Pollution

    Science.gov (United States)

    ... Topics Games Activities Lessons MENU River and Stream Pollution Kids Homepage Topics Pollution River and Stream Pollution ... stream in the first place by disturbing the land as little as possible. Farmers and construction workers ...

  18. Indoor Air Pollution

    Science.gov (United States)

    We usually think of air pollution as being outdoors, but the air in your house or office could also be polluted. Sources of indoor pollution include Mold and pollen Tobacco smoke Household products ...

  19. Wet oxidation processes for water pollution remediation

    OpenAIRE

    García Molina, Verónica

    2006-01-01

    [eng] The main objective of this work was to test the efficiency of wet oxidation processes when treating several types of aqueous wastes. On one side its performance for the abatement of chloro-organic aromatic toxic pollutants, such as 4-chlorophenol and 2,4-dichlorophenol has been studied. On the other hand, wastewater from pulp and paper mills, which has been reported to be an indirect source of entry of chlorophenols in the aquatic environment, has been investigated. More in detail, it h...

  20. Optimization of a premixed cylindrical burner for low pollutant emission

    International Nuclear Information System (INIS)

    Highlights: • The mixing uniformity of methane closely relates to low burning emissions. • Optimal exit position and diameter of nozzle are obtained with high methane mixing. • Low emissions of optimal burner are experimentally validated. - Abstract: A premixed cylindrical burner is numerically and experimentally investigated to realize low pollutant emission. The geometrical parameters of nozzle exit position and nozzle diameter are optimized by using a validated Computational Fluid Dynamics model. The natural gas-air mixing in the mix chamber indicates that the uniformity of methane concentration increases with the increase of distance from ejector outlet. It is found that the nozzle exit position at −3.0 mm improves the overall performance of premixed cylindrical burner, when nozzle diameter is not less than 1.6 mm. The emission characteristics of nitrogen oxides and carbon monoxide are also examined by experimental approach. It is found that load factor has a great influence on nitrogen oxides and carbon monoxide emissions, but the effect is gradually disappeared when air coefficient is not less than 1.4. When nozzle exit position is −3.0 mm, nozzle diameter is not less than 1.6 mm and air coefficient is not less than 1.4, the emissions of nitrogen oxides and carbon monoxide are less than 20 ppm and 50 ppm, respectively

  1. Pollution Prevention Pays: Pollution Charges in Cambodia

    OpenAIRE

    Sideth Muong

    2006-01-01

    Across the developing world, governments are grappling with the problem of industrial pollution. A new report from Cambodia looks into a system of pollution levies that would encourage polluting firms to clean up their emissions. This study sets out a series of charges that are projected to produce pollution reductions of up to 85%. It recommends a number of regulatory and administrative changes that would help bring about such an outcome.

  2. Polycyclic aromatic hydrocarbon in urban soil from Beijing, China

    Institute of Scientific and Technical Information of China (English)

    LI Xing-hong; MA Ling-ling; LIU Xiu-fen; FU Shan; CHENG Hang-xin; XU Xiao-bai

    2006-01-01

    Polycyclic aromatic hydrocarbons (EPA-PAHs) in the urban surface soils from Beijing were determined using gas chromatography and mass spectrometry (GC-MS). It is significantly complementary for understanding the PAHs pollution in soil of integrated Beijing city on the basis of the information known in the outskirts. The total concentration of 16 EPA-PAH was from 0.467 to 5.470 μg/g and was described by the contour map. Compound profiles presented that the 4-, 5- and 6-ring PAHs were major compositions. The correlation analysis showed that PAHs have the similar source in the most sampling sites and BaP might be considered as the indicator of PAHs. Characteristic ratios of anthracene (An)/(An+ phenanthrene (Phe)), fluoranthene (Flu)/(Flu+pyrene (Pyr)) and benzo[a]pyrene (BaP)/benzo[g,h,i]perylene (BghiP) indicated that the PAHs pollutants probably mainly originated from the coal combustion and it was not negligible from vehicular emission. The level of PAHs in our study area was compared with other studies.

  3. USCG Facility Pollution

    Data.gov (United States)

    Department of Homeland Security — The Marine Casualty and Pollution Data files provide details about marine casualty and pollution incidents investigated by Coast Guard Offices throughout the United...

  4. USCG Vessel Pollution

    Data.gov (United States)

    Department of Homeland Security — The Marine Casualty and Pollution Data files provide details about marine casualty and pollution incidents investigated by Coast Guard Offices throughout the United...

  5. Vertical fluxes of aromatic and aliphatic hydrocarbons in the Northwestern Mediterranean Sea

    International Nuclear Information System (INIS)

    Aliphatic and aromatic hydrocarbon fluxes were measured in time series sediment trap samples at 200 m and at 1000 m depths in the open Northwestern Mediterranean Sea, from December 2000 to July 2002. Averaged fluxes of n-alkanes, UCM and T-PAH35 were 2.96 ± 2.60 μg m-2 d-1, 64 ± 60 μg m-2 d-1 and 0.68 ± 0.59 μg m-2 d-1, respectively. Molecular compositions of both hydrocarbon classes showed a contamination in petrogenic hydrocarbons well above the background levels of such an open site, whereas pyrolytic hydrocarbons stand in the range of other open Mediterranean locations. Fluxes displayed ample interannual and seasonal variabilities, mainly related to mass flux variation while concentration evolutions trigger secondary changes in pollutant fluxes. High lithogenic flux events exported particles with a larger pollutant load than biogenic particles formed during the spring bloom and during the summer. Sinking hydrocarbons were efficiently transported from 200 m to 1000 m. - Highlights: → PAH composition, plots of diagnostic PAH ratios and the UCM abundance indicate that non aromatic and aromatic hydrocarbons in sinking particles in the Ligurian Sea were mainly of petrogenic origin. → Fluxes of T-PAH35, n-alkanes and UCM transported downward at 200 m during the year 2001 were 269, 1218 and 26 910 mg m-2 yr-1, respectively. → Vertical fluxes of aliphatic and aromatic hydrocarbons displayed ample seasonal and inter-annual variabilities, mainly related to mass flux variation. Concentration variation triggered smaller changes in pollutant fluxes. → High fluxes of lithogenic particles occurring from early January to early March 2001 transported about 45% of the annual vertical export of contaminants. In April-May, high fluxes of biogenic particles also transported a significant fraction of pollutants, despite the dilution of petrogenic and pyrolytic PAHs by biogenic material. - Vertical fluxes of aliphatic and aromatic hydrocarbons in the Ligurian Sea show

  6. Vertical fluxes of aromatic and aliphatic hydrocarbons in the Northwestern Mediterranean Sea

    Energy Technology Data Exchange (ETDEWEB)

    Deyme, Remi; Bouloubassi, Ioanna; Taphanel-Valt, Marie-Helene [Laboratoire d' Oceanographie et du Climat, Experimentation et Approches Numeriques (LOCEAN/IPSL), Universite Pierre et Marie Curie-CNRS-IRD-MNHN, UMR 7159, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Miquel, Juan-Carlos [Environment Laboratories, International Atomic Energy Agency, 4 Quai Antoine 1er, MC98000 Monaco, Principality of Monaco (Monaco); Lorre, Anne [Laboratoire d' Oceanographie et du Climat, Experimentation et Approches Numeriques (LOCEAN/IPSL), Universite Pierre et Marie Curie-CNRS-IRD-MNHN, UMR 7159, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Marty, Jean-Claude [CNRS- Universite Pierre et Marie Curie, UMR 7093, LOV, Observatoire oceanographique, 06234 Villefranche/mer (France); Mejanelle, Laurence, E-mail: laurence.mejanelle@upmc.fr [Laboratoire d' ECObiogeochimie Benthique, FRE3350, CNRS-Universite Pierre et Marie Curie, Avenue du Fontaule, 66650 Banyuls Sur Mer (France)

    2011-12-15

    Aliphatic and aromatic hydrocarbon fluxes were measured in time series sediment trap samples at 200 m and at 1000 m depths in the open Northwestern Mediterranean Sea, from December 2000 to July 2002. Averaged fluxes of n-alkanes, UCM and T-PAH{sub 35} were 2.96 {+-} 2.60 {mu}g m{sup -2} d{sup -1}, 64 {+-} 60 {mu}g m{sup -2} d{sup -1} and 0.68 {+-} 0.59 {mu}g m{sup -2} d{sup -1}, respectively. Molecular compositions of both hydrocarbon classes showed a contamination in petrogenic hydrocarbons well above the background levels of such an open site, whereas pyrolytic hydrocarbons stand in the range of other open Mediterranean locations. Fluxes displayed ample interannual and seasonal variabilities, mainly related to mass flux variation while concentration evolutions trigger secondary changes in pollutant fluxes. High lithogenic flux events exported particles with a larger pollutant load than biogenic particles formed during the spring bloom and during the summer. Sinking hydrocarbons were efficiently transported from 200 m to 1000 m. - Highlights: > PAH composition, plots of diagnostic PAH ratios and the UCM abundance indicate that non aromatic and aromatic hydrocarbons in sinking particles in the Ligurian Sea were mainly of petrogenic origin. > Fluxes of T-PAH35, n-alkanes and UCM transported downward at 200 m during the year 2001 were 269, 1218 and 26 910 mg m{sup -2} yr{sup -1}, respectively. > Vertical fluxes of aliphatic and aromatic hydrocarbons displayed ample seasonal and inter-annual variabilities, mainly related to mass flux variation. Concentration variation triggered smaller changes in pollutant fluxes. > High fluxes of lithogenic particles occurring from early January to early March 2001 transported about 45% of the annual vertical export of contaminants. In April-May, high fluxes of biogenic particles also transported a significant fraction of pollutants, despite the dilution of petrogenic and pyrolytic PAHs by biogenic material. - Vertical fluxes of

  7. Aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil: a review.

    Science.gov (United States)

    Vranova, Valerie; Rejsek, Klement; Formanek, Pavel

    2013-01-01

    Organic acids, vitamins, and carbohydrates represent important organic compounds in soil. Aliphatic, cyclic, and aromatic organic acids play important roles in rhizosphere ecology, pedogenesis, food-web interactions, and decontamination of sites polluted by heavy metals and organic pollutants. Carbohydrates in soils can be used to estimate changes of soil organic matter due to management practices, whereas vitamins may play an important role in soil biological and biochemical processes. The aim of this work is to review current knowledge on aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil and to identify directions for future research. Assessments of organic acids (aliphatic, cyclic, and aromatic) and carbohydrates, including their behaviour, have been reported in many works. However, knowledge on the occurrence and behaviour of D-enantiomers of organic acids, which may be abundant in soil, is currently lacking. Also, identification of the impact and mechanisms of environmental factors, such as soil water content, on carbohydrate status within soil organic matter remains to be determined. Finally, the occurrence of vitamins in soil and their role in biological and biochemical soil processes represent an important direction for future research. PMID:24319374

  8. Assessment of the bioavailability and phytotoxicity of sediment spiked with polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Rončević, Srđan; Spasojević, Jelena; Maletić, Snežana; Jazić, Jelena Molnar; Isakovski, Marijana Kragulj; Agbaba, Jasmina; Grgić, Marko; Dalmacija, Božo

    2016-02-01

    Large amounts of sediment are dredged globally every year. This sediment is often contaminated with low concentrations of metals, polycyclic aromatic hydrocarbons, pesticides and other organic pollutants. Some of this sediment is disposed of on land, creating a need for risk assessment of the sediment disposal method, to minimize the degradation of environmental quality and prevent risks to human health. Evaluating the available fractions of certain polycyclic aromatic hydrocarbons is very important, as in the presence of various organisms, they are believed to be easily subject to the processes of bioaccumulation, biosorption and transformation. In order to determine the applicability of applying these methods for the evaluation of pollutant bioavailability in sediments, the desorption kinetics from the sediment of various polycyclic aromatic hydrocarbons in the presence of Tenax and XAD4 were examined over the course of 216 h. Changes in the PAH concentrations in dredged sediments using five different seed plants during a short time of period (10 days) were also followed. Using chemical extraction techniques with Tenax and XAD4, a time of around 24 h is enough to achieve equilibrium for all four PAHs. Results showed good agreement between the seed accumulation and PAH extraction methods with both agents. If we compare the two extraction techniques, XAD4 gave better results for phenanthrene, pyrene and benzo(a)pyrene, and Tenax gave better results for chrysene. PMID:26490893

  9. Aromatic measurements of diesel fuel - A CRC round-robin study

    Energy Technology Data Exchange (ETDEWEB)

    Seizinger, D.E.; Hoekman, S.K.

    1984-01-01

    A round robin study to measure the aromatic levels in diesel fuels was conducted by the Chemical Characterization Panel of the Coordinating Research Council Air Pollution Research Advisory Committee (CRC-APRAC) In-house Program Group, CAPI-1-64. The fuels for this study consisted of a jet fuel, a No. 2 diesel reference fuel, and three fuels used in a CRC-sponsored diesel emission project (CAPE-32). These fuels had 90% distillation temperatures which ranged from 472/sup 0/ to 642/sup 0/ F and aromaticity levels from approximately 18 to 55% by volume. All participants used the American Society for Testing and Materials (ASTM) D1319 or modified D1319 methods to measure the aromatic levels in the selected fuels. Some participants concurrently analyzed the same fuels using other methods such as high-performance liquid chromatography, mass spectrometry, nuclear magnetic resonance spectrometry, and elution chromatography (ASTM D2549). One non-participating laboratory analyzed the fuels using supercritical fluid chromatography. The results of nine participants using the D1319 methodology and other methods showed good agreement for fuels with 90% distillation temperatures less than 600/sup 0/ F. However, this round robin study showed that: 1) there is no standard method to measure aromatic levels in full boiling range diesel fuels, and 2) there are inadequacies when using the D1319 and modified D1319 methods for fuels outside of the specified property ranges.

  10. Numerical analysis of two and three dimensional buoyancy driven water-exit of a circular cylinder

    Directory of Open Access Journals (Sweden)

    Moshari Shahab

    2014-06-01

    Full Text Available With the development of the technology of underwater moving bodies, the need for developing the knowledge of surface effect interaction of free surface and underwater moving bodies is increased. Hence, the two-phase flow is a subject which is interesting for many researchers all around the world. In this paper, the non-linear free surface deformations which occur during the water-exit of a circular cylinder due to its buoyancy are solved using finite volume discretization based code, and using Volume of Fluid (VOF scheme for solving two phase flow. Dynamic mesh model is used to simulate dynamic motion of the cylinder. In addition, the effect of cylinder mass in presence of an external force is studied. Moreover, the oblique exit and entry of a circular cylinder with two exit angles is simulated. At last, water-exit of a circular cylinder in six degrees of freedom is simulated in 3D using parallel processing. The simulation errors of present work (using VOF method for maximum velocity and height of a circular cylinder are less than the corresponding errors of level set method reported by previous researchers. Oblique exit shows interesting results; formation of waves caused by exit of the cylinder, wave motion in horizontal direction and the air trapped between the waves are observable. In 3D simulation the visualization of water motion on the top surface of the cylinder and the free surface breaking on the front and back faces of the 3D cylinder at the exit phase are observed which cannot be seen in 2D simulation. Comparing the results, 3D simulation shows better agreement with experimental data, specially in the maximum height position of the cylinder.

  11. An overview of the AROMAT campaigns

    Science.gov (United States)

    Merlaud, Alexis; Dekemper, Emmanuel; Van Roozendael, Michel; Constantin, Daniel; Georgescu, Lucian; Meier, Andreas; Richter, Andreas; Den Hoed, Mirjam; Allaart, Marc; Boscornea, Andreea; Vajaiac, Sorin; Bellegante, Livio; Nemuc, Anca; Nicolae, Doina; Shaifangar, Reza; Dörner, Steffen; Wagner, Thomas; Stebel, Kerstin; Schuettemeyer, Dirk

    2016-04-01

    The Airborne ROmanian Measurements of Aerosols and Trace gases (AROMAT) campaign and its follow-up AROMAT-2 were held in September 2014 and August 2015, respectively. Both campaigns focused on two geophysical targets: the city of Bucharest and the large power plants of the Jiu Valley, which are located in a rural area 170 km West of Bucharest. These two areas are complementary in terms of emitted chemical species and their spatial distributions. The objectives of the AROMAT campaigns were (i) to test recently developed airborne observation systems dedicated to air quality satellite validation studies such as the AirMAP imaging DOAS system (University of Bremen), the NO2 sonde (KNMI), and the compact SWING whiskbroom imager (BIRA), and (ii) to prepare the validation programme of the future Atmospheric Sentinels, starting with Sentinel-5 Precursor (S5P) to be launched in early summer 2016. We present results from the different airborne instrumentations and from coincident ground-based measurements (lidar, in-situ, and mobile DOAS systems) performed during both campaigns. The AROMAT dataset addresses several of the mandatory products of TROPOMI/S5P, in particular NO2 and SO2 (horizontal distribution and profile from aircraft, plume image with ground-based SO2 and NO2 cameras, transects with mobile DOAS, in-situ), H2CO (mobile MAX-DOAS), and aerosols (lidar, airborne FUBISS-ASA2 sun-photometer, and aircraft in-situ). We investigate the information content of the AROMAT dataset for satellite validation studies based on co-located OMI and GOME-2 data, and simulations of TROPOMI measurements. The experience gained during AROMAT and AROMAT-2 will be used in support of a large-scale TROPOMI/S5P validation campaign in Romania scheduled for summer 2017.

  12. Polycyclic aromatic hydrocarbons in soil and plants. A contribution to the assessment of hazards from land contamination. Vol. 1. Methods of analysis

    International Nuclear Information System (INIS)

    The assessment of environmental hazards emanating from a group of pollutants presupposes, inter alia, knowledge of their quantities. To establish these requires a reliable analytical method for the qualitative and quantitative determination of the groups of organic pollutants to be investigated. In the case of polycyclic aromatic hydrocarbons the task set was to develop methods permitting to reliably determine PAH concentrations in soil and plants routinely. (orig.)

  13. Ovarian cancer mortality and industrial pollution.

    Science.gov (United States)

    García-Pérez, Javier; Lope, Virginia; López-Abente, Gonzalo; González-Sánchez, Mario; Fernández-Navarro, Pablo

    2015-10-01

    We investigated whether there might be excess ovarian cancer mortality among women residing near Spanish industries, according to different categories of industrial groups and toxic substances. An ecologic study was designed to examine ovarian cancer mortality at a municipal level (period 1997-2006). Population exposure to pollution was estimated by means of distance from town to facility. Using Poisson regression models, we assessed the relative risk of dying from ovarian cancer in zones around installations, and analyzed the effect of industrial groups and pollutant substances. Excess ovarian cancer mortality was detected in the vicinity of all sectors combined, and, principally, near refineries, fertilizers plants, glass production, paper production, food/beverage sector, waste treatment plants, pharmaceutical industry and ceramic. Insofar as substances were concerned, statistically significant associations were observed for installations releasing metals and polycyclic aromatic chemicals. These results support that residing near industries could be a risk factor for ovarian cancer mortality. PMID:26046426

  14. Biosurfactant-enhanced bioremediation of hydrophobic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Cameotra, S.S.; Makkar, R.S. [Inst. of Microbial Technology, Chandigarh (India)

    2010-01-15

    Biosurfactants are surface-active compounds synthesized by a wide variety of microorganisms. They are molecules that have both hydrophobic and - philic domains and are capable of lowering the surface tension and the interfacial tension of the growth medium. Biosurfactants possess different chemical structures-lipopeptides, glycolipids, neutral lipids, and fatty acids. They are nontoxic biomolecules that are biodegradable. Biosurfactants also exhibit strong emulsification of hydrophobic compounds and form stable emulsions. Polycyclic aromatic hydrocarbons (PAHs), crude on sludge, and pesticides call be toxic, mutagenic, and carcinogenic compounds that pollute the environment. They are released into the environment as a result of oil spillage and by-products of coal treatment processes. The low water solubility of these compounds limits their availability to microorganisms, which is a potential problem for bioremediation of contaminated sites. Microbially produced surfactants enhance the bioavailability of these hydrophobic compounds for bioremediation. Therefore, biosurfactant-enhanced solubility of pollutants has potential hioremediation applications.

  15. CFD Investigation of Pollutant Emission in Can-Type Combustor Firing Natural Gas, LNG and Syngas

    Science.gov (United States)

    Hasini, H.; Fadhil, SSA; Mat Zian, N.; Om, NI

    2016-03-01

    CFD investigation of flow, combustion process and pollutant emission using natural gas, liquefied natural gas and syngas of different composition is carried out. The combustor is a can-type combustor commonly used in thermal power plant gas turbine. The investigation emphasis on the comparison of pollutant emission such in particular CO2, and NOx between different fuels. The numerical calculation for basic flow and combustion process is done using the framework of ANSYS Fluent with appropriate model assumptions. Prediction of pollutant species concentration at combustor exit shows significant reduction of CO2 and NOx for syngas combustion compared to conventional natural gas and LNG combustion.

  16. Comparison of Benzene & Toluene removal from synthetic polluted air with use of Nano photocatalyticTiO2/ ZNO process

    OpenAIRE

    Gholami, Mitra; Nassehinia, Hamid Reza; Jonidi-Jafari, Ahmad; NASSERI, Simin; Esrafili, Ali

    2014-01-01

    Background Mono aromatic hydrocarbons (BTEX) are a group of hazardous pollutants which originate from sources such as refineries, gas, and oil extraction fields, petrochemicals and paint and glue industries. Conventional methods, including incineration, condensation, adsorption and absorption have been used for removal of VOCs. None of these methods is economical for removal of pollutants of polluted air with low to moderate concentrations. The heterogeneous photocatalytic processes involve t...

  17. Mechanistic studies on the OH-initiated atmospheric oxidation of selected aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Nehr, Sascha

    2012-07-01

    Benzene, toluene, the xylenes, and the trimethylbenzenes are among the most abundant aromatic trace constituents of the atmosphere mainly originating from anthropogenic sources. The OH-initiated atmospheric photo-oxidation of aromatic hydrocarbons is the predominant removal process resulting in the formation of O{sub 3} and secondary organic aerosol. Therefore, aromatics are important trace constituents regarding air pollution in urban environments. Our understanding of aromatic photo-oxidation processes is far from being complete. This work presents novel approaches for the investigation of OH-initiated atmospheric degradation mechanisms of aromatic hydrocarbons. Firstly, pulsed kinetic studies were performed to investigate the prompt HO{sub 2} formation from OH+ aromatic hydrocarbon reactions under ambient conditions. For these studies, the existing OH reactivity instrument, based on the flash photolysis/laser-induced fluorescence (FP/LIF) technique, was extended to the detection of HO{sub 2} radicals. The experimental design allows for the determination of HO{sub 2} formation yields and kinetics. Results of the pulsed kinetic experiments complement previous product studies and help to reduce uncertainties regarding the primary oxidation steps. Secondly, experiments with aromatic hydrocarbons were performed under atmospheric conditions in the outdoor atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction chamber) located at Forschungszentrum Juelich. The experiments were aimed at the evaluation of up-to-date aromatic degradation schemes of the Master Chemical Mechanism (MCMv3.2). The unique combination of analytical instruments operated at SAPHIR allows for a detailed investigation of HO{sub x} and NO{sub x} budgets and for the determination of primary phenolic oxidation product yields. MCMv3.2 deficiencies were identified and most likely originate from shortcomings in the mechanistic representation of ring

  18. Locational evaluation of chemical soil pollution. Lectures; Standortgerechte Bewertung chemischer Bodenbelastungen. Beitraege

    Energy Technology Data Exchange (ETDEWEB)

    Doerfler, U.; Schulte-Hostede, S. [eds.

    1997-12-31

    This lecture event dealt with the following subjects: Deposition, transport and interactions of organic pollutants in soil, such as pesticides and polycyclic aromatic hydrocarbons. Biological availability of pollutants, influence of other substances on the biological availability of pollutants, quantitative and qualitative analyses of pollutants in soil, toxicity. (SR) [Deutsch] Themen dieser Vortragsveranstaltung waren: Deposition, Transport und Wechselwirkungen organischer Schadstoffe im Boden, wie Pestizide und polycyclische Aromatische Kohlenwasserstoffe. Bioverfuegbarkeit der Schadstoffe, Einfluss anderer Substanzen auf die Bioverfuegbarkeit der Schadstoffe, quantitative und qualitative Analyse von Schadstoffen im Boden, Toxizitaet. (SR)

  19. Comparison of flight speed and exit score as measurements of temperament in beef cattle.

    Science.gov (United States)

    Vetters, M D D; Engle, T E; Ahola, J K; Grandin, T

    2013-01-01

    Observations were collected for the purpose of comparing exit velocity measurements in the form of exit score (ES; walk, trot, canter, or run) and flight speed (FS) as assessments of cattle temperament. Squeeze chute exit velocity was obtained for 1,181 crossbred yearling steers using ES and FS temperament systems. Flight speed used infrared sensors to determine the time taken for an animal to traverse a fixed distance of 1.83 m after exiting the squeeze chute. Exit score (1=walk, 2=trot, 3=canter, and 4=run) was assigned by 2 different observers when each steer crossed a fixed point between the infrared sensors. All animals were scored with each system (ES and FS) simultaneously on exiting the squeeze chute on d -21 and d -1 of the experiment. Of the 1,181 cattle, 357 were moved to a nearby research feedyard for use in a 140 d feedlot trial. These cattle were scored using both measurement systems and BW was recorded at 35 d intervals throughout the trial. Exit score was assessed for observer reliability, ES and FS were compared for measurement repeatability, and both were assessed on ability to predict ADG. Exit score between observers on a single day showed considerable agreement (weighted Kappa=0.66), indicating the system was reliable between different observers. However, the agreement for a single observer between day was only moderate (weighted Kappa=0.40), indicating a day effect for ES. In addition, although mean velocities for day were not different (P>0.18; FS=2.98±.87 and 3.02±0.87 m/s for day, respectively), the persistence of FS for each animal was low (Spearman rank correlation coefficient=0.25). The frequency that an animal would be placed into the same third of FS or receive the same ES on consecutive weigh days was 50% and 60.0%, respectively, and both were moderate predictors of ADG (R2=0.14 and R2=0.17). These data indicate that ES and FS are reliable instruments for assessment of temperament on a given day, and show moderate repeatability

  20. Ectomycorrhizas impede phytoremediation of polycyclic aromatic hydrocarbons (PAHs) both within and beyond the rhizosphere

    Energy Technology Data Exchange (ETDEWEB)

    Joner, Erik J. [Laboratoire des Interactions Microorganismes-Mineraux-Matiere Organique dans les Sols (LIMOS), Universite H. Poincare Nancy 1, P.O. Box 239, F-54506 Vandoeuvre-les-Nancy (France)]. E-mail: erik.joner@jordforsk.no; Leyval, Corinne [Laboratoire des Interactions Microorganismes-Mineraux-Matiere Organique dans les Sols (LIMOS), Universite H. Poincare Nancy 1, P.O. Box 239, F-54506 Vandoeuvre-les-Nancy (France); Colpaert, Jan V. [Centre for Environmental Sciences, Environmental Biology Group, Hasselt University, Agoralaan, Gebouw D, B-3590 Diepenbeek (Belgium)

    2006-07-15

    Exploitation of mycorrhizas to enhance phytoremediation of organic pollutants has received attention recently due to their positive effects on establishment of plants in polluted soils. Some evidence exist that ectomycorrhizas enhance the degradation of pollutants of low recalcitrance, while less easily degradable polyaromatic molecules have been degraded only by some of these fungi in vitro. Natural polyaromatic (humic) substances are degraded more slowly in soil where ectomycorrhizal fungi are present, thus phytoremediation of recalcitrant pollutants may not benefit from the presence of these fungi. Using a soil spiked with three polycyclic aromatic hydrocarbons (PAHs) and an industrially polluted soil (1 g kg{sup -1} of {sigma}12 PAHs), we show that the ectomycorrhizal fungus Suillus bovinus, forming hydrophobic mycelium in soil that would easily enter into contact with hydrophobic pollutants, impedes rather than promotes PAH degradation. This result is likely to be a nutrient depletion effect caused by fungal scavenging of mineral nutrients. - The ectomycorrhizal fungus S. bovinus impeded degradation of PAHs in soil, probably due to its negative effect on the availability of mineral nutrients of more potent PAH degraders.

  1. Ectomycorrhizas impede phytoremediation of polycyclic aromatic hydrocarbons (PAHs) both within and beyond the rhizosphere

    International Nuclear Information System (INIS)

    Exploitation of mycorrhizas to enhance phytoremediation of organic pollutants has received attention recently due to their positive effects on establishment of plants in polluted soils. Some evidence exist that ectomycorrhizas enhance the degradation of pollutants of low recalcitrance, while less easily degradable polyaromatic molecules have been degraded only by some of these fungi in vitro. Natural polyaromatic (humic) substances are degraded more slowly in soil where ectomycorrhizal fungi are present, thus phytoremediation of recalcitrant pollutants may not benefit from the presence of these fungi. Using a soil spiked with three polycyclic aromatic hydrocarbons (PAHs) and an industrially polluted soil (1 g kg-1 of Σ12 PAHs), we show that the ectomycorrhizal fungus Suillus bovinus, forming hydrophobic mycelium in soil that would easily enter into contact with hydrophobic pollutants, impedes rather than promotes PAH degradation. This result is likely to be a nutrient depletion effect caused by fungal scavenging of mineral nutrients. - The ectomycorrhizal fungus S. bovinus impeded degradation of PAHs in soil, probably due to its negative effect on the availability of mineral nutrients of more potent PAH degraders

  2. Effects of the geometric orientations of the nozzle exit on the breakup of free liquid jet

    Energy Technology Data Exchange (ETDEWEB)

    Lad, V. N.; Murthy, Z. V. P. [Sardar Vallabhbhai National Institute of Technology, Gujarat (India)

    2016-04-15

    Free liquid jets are produced through various geometric orientations of the nozzle exit. The breakup lengths of liquid jets under various geometric orientations of the nozzle exit were studied. Images of jets were captured using a high-speed camera with a maximum frame rate of 1000 frames per second and were analyzed to determine the dynamics between jets and breakup lengths. The breakup length of jets changes with the cut angle of the nozzle exit. In addition, adding polymer reduces the effect of the cut angle of the nozzle exit on the breakup length for an entire range of velocities. The effect of the cut angle on breakup length is predominant for aqueous solutions with surfactants. This work provides motivation for further computational research to study jet dynamics in a partially covered nozzle exit, such as the case in which the boundary conditions near the nozzle opening is more complex with the cut angle and its vertex position, which directly reflects liquid jet dynamics.

  3. Ecotoxicity of a polycyclic aromatic hydrocarbon (PAH)-contaminated soil.

    Science.gov (United States)

    Eom, I C; Rast, C; Veber, A M; Vasseur, P

    2007-06-01

    Soil samples from a former cokery site polluted with polycyclic aromatic hydrocarbons (PAHs) were assessed for their toxicity to terrestrial and aquatic organisms and for their mutagenicity. The total concentration of the 16 PAHs listed as priority pollutants by the US Environmental Protection Agency (US-EPA) was 2634+/-241 mg/kgdw in soil samples. The toxicity of water-extractable pollutants from the contaminated soil samples was evaluated using acute (Vibrio fischeri; Microtox test, Daphnia magna) and chronic (Pseudokirchneriella subcapitata, Ceriodaphnia dubia) bioassays and the EC values were expressed as percentage water extract in the test media (v/v). Algal growth (EC50-3d=2.4+/-0.2% of the water extracts) and reproduction of C. dubia (EC50-7d=4.3+/-0.6%) were the most severely affected, compared to bacterial luminescence (EC50-30 min=12+/-3%) and daphnid viability (EC50-48 h=30+/-3%). The Ames and Mutatox tests indicated mutagenicity of water extracts, while no response was found with the umu test. The toxicity of the soil samples was assessed on the survival and reproduction of earthworms (Eisenia fetida) and collembolae (Folsomia candida), and on the germination and growth of higher plants (Lactuca sativa L.: lettuce and Brassica chinensis J.: Chinese cabbage). The EC50 values were expressed as percentage contaminated soil in ISO soil test medium (weight per weight-w/w) and indicated severe effects on reproduction of the collembola F. candida (EC50-28 d=5.7%) and the earthworm E. fetida (EC50-28 d=18% and EC50-56 d=8%, based on cocoon and juvenile production, respectively). Survival of collembolae was already affected at a low concentration of the contaminated soil (EC50-28 d=11%). The viability of juvenile earthworms was inhibited at much lower concentrations of the cokery soil (EC50-14 d=28%) than the viability of adults (EC50-14 d=74%). Only plant growth was inhibited (EC50-17d=26%) while germination was not. Chemical analyses of water extracts allowed

  4. Engineering dioxygenases for efficient degradation of environmental pollutants.

    Science.gov (United States)

    Furukawa, K

    2000-06-01

    Dioxygenases have recently been engineered to improve their capabilities for environmental pollutant degradation. The techniques used to achieve this include in vitro DNA shuffling and subunit or domain exchanges between dioxygenases of different bacterial origins. Such evolved enzymes acquire novel and enhanced degradation capabilities of xenobiotic compounds, such as polychlorinated biphenyls, trichloroethylene and a variety of aromatic compounds. Hybrid strains in which the evolved genes are integrated into the chromosomal operons exhibit efficient degradation of xenobiotic chlorinated compounds. PMID:10851151

  5. Terrestrial mosses as biomonitors of atmospheric POPs pollution: a review

    OpenAIRE

    Harmens, H.; Foan, L.; Simon, V; Mills, G.

    2013-01-01

    Worldwide there is concern about the continuing release of persistent organic pollutants (POPs) into the environment. In this study we review the application of mosses as biomonitors of atmospheric deposition of POPs. Examples in the literature show that mosses are suitable organisms to monitor spatial patterns and temporal trends of atmospheric concentrations or deposition of POPs. These examples include polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs), dioxins and furans ...

  6. Bioindicators of pollutant exposure in the northwestern Mediterranean sea

    OpenAIRE

    Burgeot, Thierry; Bocquene, Gilles; Porte, C.; Dimeet, Joel; Santella, RM; Garcia De La Parra, L.m.; Pihol-leszkowicz, A.; Raoux, C; Galgani, Francois

    1996-01-01

    Several bioindicators were used to evaluate the biological and genotoxic effects of marine pollutants near large coastal cities in the northwestern part of the Mediterranean Sea. Three target species of teleosts were selected: red mullet Mullus barbatus and 2 types of comber (Serranus hepatus and S. cabrilla). Induction of ethoxyresorufin-O-deethylase (EROD) activity specific for polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) was measured in the livers of the fish,...

  7. Silicone elastomers with aromatic voltage stabilizers

    DEFF Research Database (Denmark)

    A Razak, Aliff Hisyam; Skov, Anne Ladegaard

    insulation cables.3–5 As an alternative to utilise additives as voltage stabilizers, grafting aromatic compounds to silicone backbones may overcome the common problem of insolubility of the aromatic voltage stabilizer in the silicone elastomers due to phase separation. Preventing phase separation during...... via hydrosilylation by a vinyl-functional crosslinker. The mechanism of electron-trapping by aromatic compounds grafted to silicone backbones in a crosslinked PDMS is illustrated in Fig. 1. The electrical breakdown strength, the storage modulus and the loss modulus of the elastomer were investigated...... attached to the silicone backbone. The dielectric relative permittivity of PDMS-PPMS copolymers remained between 2 to 3 with low conductivity and low dielectric loss as well as high storage moduli with low viscous loss, thereby maintaining the electro-mechanical integrity of the elastomer....

  8. Chemotaxis of Azospirillum species to aromatic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-de-Victoria, G.; Lovell, C.R. (Univ. of South Carolina, Columbia, SC (United States))

    1993-09-01

    Azospirillum sspeciesare free-living nitrogen fixing bacteria commonly found in soils and in association with plant roots, including important agricultural crops. Rhizosphere colonization my Azospirillum species has been shown to stimulate growth of a variety of plant species. Chemotaxis is one of the properties which may contribute to survival, rhizosphere colonization and the initiation of mutualistic interactions by Azospirillum species. This study evaluates the chemotactic responses of three Azospirillum stains to a variety of aromatic compounds:benzoate, catechol, 4-HB, and PCA. Results indicate that the same aromatic substance can elicit different chemotactic responses from different Azospirillum species, and that Azospirillum can detect aromatic substrates at concentrations similar to those they encounter naturally. 36 refs., 1 fig., 6 tabs.

  9. 典型印染废水处理过程中芳香烃化合物的污染特征及污泥生态风险评价∗%Pollution characteristics of aromatic hydrocarbons and ecological risk assessment of the sludge in the typical textile dyeing wastewater treatment process

    Institute of Scientific and Technical Information of China (English)

    王靖宇; 宁寻安; 李锐敬; 温炜彬; 杨佐毅; 贺睿哲; 刘敬勇

    2015-01-01

    采用GC⁃MS测定了典型综合印染废水处理厂废水和污泥中芳香烃化合物的含量.结果表明,原水中苯系物总量为203.96±15.18μg·L-1,其中二甲苯占62.7%,尾水中苯系物总量为0.2±0.029μg·L-1,整个处理工艺对苯系物的去除效率为99%.原水中多环芳烃(PAHs)总浓度达1349.51±35.77 ng·L-1,以3—6环为主,主要富集在颗粒物上.整个工艺对PAHs的去除效率为95%,尾水中PAHs总浓度为65.81±20.99 ng·L-1,以2—3环为主.干污泥中PAHs含量高达2996.10±151.0 ng·g-1,污泥吸附为水相中PAHs去除的主要机理之一.印染污泥直接填埋或农用会引起潜在的生态危害.%Aromatic hydrocarbons were detected by gas chromatography⁃mass spectrometry in wastewater and sludge from a typical integrated textile dyeing wastewater treatment plant. Results demonstrated that ∑BTEX concentration in raw wastewater was 203.96±15.18μg·L-1, and xylenes accounted for 62.7% of the total BTEX. The entire process achieved 99% removal for∑BTEX, and∑BTEX concentration of the final effluent was 0.2±0.029 μg·L-1. In the raw wastewater, the total polycyclic aromatic hydrocarbons (PAHs) concentration was 1349.51±35.77 ng·L-1, and the PAHs were mainly adsorbed onto the suspended particles present in the raw wastewater. The dominant compounds were 3—6 ring PAHs in the raw wastewater, while 2—3 ring PAHs predominated in the final effluent. ∑PAHs concentration in the dry sludge was 2996�10±151.0 ng·g-1, and adsorption to sludge was one of the significant removal mechanisms for PAHs in the aqueous phase. The landfill and agricultural reuse of the textile dyeing sludge may cause potential risk to ecosystem.

  10. Biochemical ripening of dredged sediments. Part 2. Degradation of polycyclic aromatic hydrocarbons and total petroleum hydorcarbons in slurried and consolidated sediments

    NARCIS (Netherlands)

    Vermeulen, J.; Gool, van M.P.M.; Mentink, G.H.; Joziasse, J.; Bruning, H.; Grotenhuis, J.T.C.

    2007-01-01

    Ripening of polycyclic aromatic hydrocarbons (PAH) and total petroleum hydrocarbons (TPH) polluted dredged sediment can be considered as a bioremediation technique. Aerobic biodegradation of PAH and TPH was studied in five previously anaerobic-slurried sediments during a 350-d laboratory incubation

  11. Application of the evaluating methods of the stocks at the exit from the patrimony in Romania

    Directory of Open Access Journals (Sweden)

    Claudia Sîrbulescu

    2016-05-01

    Full Text Available In the present paper I intend to approach the evaluation of material current assets at the exit from the heritage, concidering the changes occurred in recent years in the accounting system from Romania and considering the importance that the stocks has on the result of the exercise. Throughout the paper we highlighted the general aspects regarding the stocks, stocks evaluation, and also the advantages and disadvantages in the use of evaluation methods of the stocks at the exit from the patrimony from the Romanian system. Starting from the aspects with general character and in full conformity with International Accounting Standards, we presented calculation methods used in evaluation of stocks at the exit from patrimony.

  12. Organized medicine and Scandinavian professional unionism: hospital policies and exit options in Denmark and Sweden.

    Science.gov (United States)

    Heidenheimer, A J; Johansen, L N

    1985-01-01

    Strikes by junior hospital doctors over the issue of on-call remuneration in Denmark and Sweden in 1981 are analyzed to clarify the impact of public-sector cost-control policies on intra- and interprofessional solidarity within the Scandinavian professional peak associations. The junior doctors' grievances could find expression either through increased "voice" within the medical negotiating machinery, or by pursuing the exit option in having the medical associations quit the peak associations. The article explains why the "exit" option was selected in Denmark, while in Sweden the granting of additional voice helped persuade the medical association to withdraw its exit threat and to remain within the peak association. The two cases are interpreted as presaging a divergence in the paths being taken by the various Scandinavian welfare states. PMID:4045171

  13. Experimental research and numerical simulation on impeller exit flow field of bulb tubular pump

    International Nuclear Information System (INIS)

    Three dimensional Laser Doppler Velocimetry (3D-LDV) technique was used to measure the impeller exit flow field of bulb tubular pump, the average velocity distribution of the exit section was obtained, and the energy performance of bulb tubular pump was obtained by model test. The flow field of tubular pump also simulated by CFD based on Navier-Stokes equations and RNG k-ε model. The calculated performance curve was consistent with the model test results, and the calculated velocities of impeller exit compared with the LDV measurement results, it was shown that the distribution of circumferential velocity and axial velocity were close to each other, but the radial velocity deviation between the LDV results and the CFD ones was obviously, the reasons of deviation were analyzed. The experimental results can provide the references for the impeller and diffuser design of tubular pumps, it also can improve the accuracy of calculation and perfect simulation.

  14. Light radiation at the exit of RFQ and RF-field control

    International Nuclear Information System (INIS)

    A high quality of beams and recurrence of their parameters are the important characteristic for RFQ-ion implanters. A qualitative run of the proposed designs depends on operative field control in a RF-cavity. The results of the first stage investigations of light emission at the exit of H and 2H RF-cavities unloaded by a beam are presented. A strong dependence of the intensity of light radiation on the material of the vacuum chamber beyond the exit aperture of the cavities, on the RF power value and independence of this intensity of vacuum conditions inside and outside the cavities (over a large range of pressure changes) are shown. This radiation generated by the electrons leaving the cavity through the exit aperture can be used for real-time nonperturbative RF-field control. 14 refs., 2 figs

  15. Hedgehog signaling acts with the temporal cascade to promote neuroblast cell cycle exit.

    Directory of Open Access Journals (Sweden)

    Phing Chian Chai

    Full Text Available In Drosophila postembryonic neuroblasts, transition in gene expression programs of a cascade of transcription factors (also known as the temporal series acts together with the asymmetric division machinery to generate diverse neurons with distinct identities and regulate the end of neuroblast proliferation. However, the underlying mechanism of how this "temporal series" acts during development remains unclear. Here, we show that Hh signaling in the postembryonic brain is temporally regulated; excess (earlier onset of Hh signaling causes premature neuroblast cell cycle exit and under-proliferation, whereas loss of Hh signaling causes delayed cell cycle exit and excess proliferation. Moreover, the Hh pathway functions downstream of Castor but upstream of Grainyhead, two components of the temporal series, to schedule neuroblast cell cycle exit. Interestingly, hh is likely a target of Castor. Hence, Hh signaling provides a link between the temporal series and the asymmetric division machinery in scheduling the end of neurogenesis.

  16. Peritonitis and catheter exit-site infection in patients on peritoneal dialysis at home1

    Science.gov (United States)

    Abud, Ana Cristina Freire; Kusumota, Luciana; dos Santos, Manoel Antônio; Rodrigues, Flávia Fernanda Luchetti; Damasceno, Marta Maria Coelho; Zanetti, Maria Lúcia

    2015-01-01

    Objective: to analyze the complications related to peritonitis and catheter exit-site infections, in patients on peritoneal dialysis at home. Method: quantitative and cross-sectional study, carried out with 90 patients on peritoneal dialysis at home, in a municipality in the Northeast region of Brazil. For data collection, it was used two structured scripts and consultation on medical records. Descriptive analysis and comparison tests among independent groups were used, considering p<0.05 as level of statistical significance. Results: by comparing the frequency of peritonitis and the length of treatment, it was found that patients over two years of peritoneal dialysis were more likely to develop peritonitis (X²=6.39; p=0.01). The number of episodes of peritoneal catheter exit-site infection showed association with the length of treatment (U=224,000; p=0.015). Conclusion: peritonitis and catheter exit-site infection are associated with the length of treatment. PMID:26487141

  17. Demographic analysis of foreign visitors to the EXIT festival, Novi Sad

    Directory of Open Access Journals (Sweden)

    Bjeljac Željko

    2011-01-01

    Full Text Available In this paper we studied the habits and behaviour of visitors of EXIT tourist event in Novi Sad. The research was conducted on a sample of 189 randomly selected respondents from abroad. The aim was to determine whether there is a difference in the motives of foreign tourists coming to EXIT, a selection of vehicles, as well as the use of various means of tourist propaganda and the structure of expenditure of funds at foreign visitors. EXIT festival, Novi Sad has been selected for the survey because of growing brand of the festival in the total tourist offer of Serbia, specific groups of visitors, the number of foreign tourists, the links with the locality of maintaining.

  18. Removal of polycyclic aromatic hydrocarbons from aqueous solution using plant residue materials as a biosorbent

    Energy Technology Data Exchange (ETDEWEB)

    Chen Baoliang, E-mail: blchen@zju.edu.cn [Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310028 (China); Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou, Zhejiang 310028 (China); Yuan Miaoxin; Liu Hao [Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310028 (China); Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou, Zhejiang 310028 (China)

    2011-04-15

    Graphical abstract: The structure-effect relationship provides a reference to select and modify plant residues as a biosorbent with high efficiency to tackle organic pollutants. Research highlights: {yields} Polycyclic aromatic hydrocarbons are effectively removed by plant residues. {yields} Biosorption mechanism of plant residues to abate PAHs is a partitioning process. {yields} Partition coefficients are negatively related with sugar contents of biosorbent. {yields} The aromatic component and K{sub ow} exhibit positive effects on biosorption. {yields} The structure-effect relationship guides plant residue using as a biosorbent. - Abstract: To elucidate biosorption mechanism and removal efficiency of plant residues as a biosorbent to abate polycyclic aromatic hydrocarbons (PAHs) in wastewater, sorption of PAHs onto wood chips (WC), ryegrass roots (RR), orange peels (OP), bamboo leaves (BL), and pine needles (PN) were investigated. The structural characterization of the biosorbents was analyzed by elemental composition, BET-N{sub 2} surface area, and Fourier transform infrared spectroscopy. PAHs sorption to the selected biosorbents were compared and correlated with their structures. Biosorption isotherms fit well with Freundlich equation and the mechanism was dominated by partition process. The magnitude of phenanthrene partition coefficients (K{sub d}) followed the order of PN > BL > OP > RR > WC, ranged from 2484 {+-} 24.24 to 5306 {+-} 92.49 L/kg. Except the WC sample, the K{sub d} values were negatively correlated with sugar content, polar index [(N + O)/C] of the biosorbents, while the aromatic component exhibited positive effects. For a given biosorbent of bamboo leaves, the carbon-normalized partition coefficients (K{sub oc}) were linearly correlated with octanol-water partition coefficients (K{sub ow}) of PAHs, i.e., log K{sub oc} = 1.16 log K{sub ow} - 1.21. The structure-effect relationship provides a reference to select and modify plant residues as a

  19. Removal of polycyclic aromatic hydrocarbons from aqueous solution using plant residue materials as a biosorbent

    International Nuclear Information System (INIS)

    Graphical abstract: The structure-effect relationship provides a reference to select and modify plant residues as a biosorbent with high efficiency to tackle organic pollutants. Research highlights: → Polycyclic aromatic hydrocarbons are effectively removed by plant residues. → Biosorption mechanism of plant residues to abate PAHs is a partitioning process. → Partition coefficients are negatively related with sugar contents of biosorbent. → The aromatic component and Kow exhibit positive effects on biosorption. → The structure-effect relationship guides plant residue using as a biosorbent. - Abstract: To elucidate biosorption mechanism and removal efficiency of plant residues as a biosorbent to abate polycyclic aromatic hydrocarbons (PAHs) in wastewater, sorption of PAHs onto wood chips (WC), ryegrass roots (RR), orange peels (OP), bamboo leaves (BL), and pine needles (PN) were investigated. The structural characterization of the biosorbents was analyzed by elemental composition, BET-N2 surface area, and Fourier transform infrared spectroscopy. PAHs sorption to the selected biosorbents were compared and correlated with their structures. Biosorption isotherms fit well with Freundlich equation and the mechanism was dominated by partition process. The magnitude of phenanthrene partition coefficients (Kd) followed the order of PN > BL > OP > RR > WC, ranged from 2484 ± 24.24 to 5306 ± 92.49 L/kg. Except the WC sample, the Kd values were negatively correlated with sugar content, polar index [(N + O)/C] of the biosorbents, while the aromatic component exhibited positive effects. For a given biosorbent of bamboo leaves, the carbon-normalized partition coefficients (Koc) were linearly correlated with octanol-water partition coefficients (Kow) of PAHs, i.e., log Koc = 1.16 log Kow - 1.21. The structure-effect relationship provides a reference to select and modify plant residues as a biosorbent with high efficiency to tackle organic pollutants.

  20. Production of aromatics from di- and polyoxygenates

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Taylor; Blank, Brian; Jones, Casey; Woods, Elizabeth; Cortright, Randy

    2016-08-02

    Methods, catalysts, and reactor systems for producing in high yield aromatic chemicals and liquid fuels from a mixture of oxygenates comprising di- and polyoxygenates are disclosed. Also disclosed are methods, catalysts, and reactor systems for producing aromatic chemicals and liquid fuels from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like; and methods, catalysts, and reactor systems for producing the mixture of oxygenates from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like. The disclosed catalysts for preparing the mixture of oxygenates comprise a Ni.sub.nSn.sub.m alloy and a crystalline alumina support.

  1. Global aromatics supply. Today and tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Bender, M. [BASF SE, Ludwigshafen (Germany)

    2013-11-01

    Aromatics are the essential building blocks for some of the largest petrochemical products in today's use. To the vast majority they are consumed to produce intermediates for polymer products and, hence, contribute to our modern lifestyle. Their growth rates are expected to be in line with GDP growth in future. This contrasts the significantly lower growth rates of the primary sources for aromatics - fuel processing and steam cracking of naphtha fractions. A supply gap can be expected to open up in future for which creative solutions will be required. (orig.)

  2. Electron beam irradiation effects on aromatic polymers

    International Nuclear Information System (INIS)

    Electron irradiation effects on aromatic polymers having various molecular structures were studied to elucidate the following subjects; (1) relation between radiation stability and molecular structure of repeating units, (2) mechanism of deterioration and (3) adaptability to matrix resin for radiation resistant FRP. Results are summarized as follows: (1) An order of radiation stability of units is; imide ring > diphenyl ether, diphenyl ketone > aromatic amide >> bis-phenol A > diphenyl sulphone. (2) Poly (ether-ether-ketone) and most polyimide are crosslinkable but polysulphones and polyarylate are chain degradation type polymers. (3) Newly developed thermoplastic polyimides have possibilities for use as matrix materials in radiation resistant FRP. (author)

  3. The use of an electronic portal imaging device for exit dosimetry and quality control measurements

    International Nuclear Information System (INIS)

    Purpose: To determine ways in which electronic portal imaging devices (EPIDs) could be used to (a) measure exit doses for external beam radiotherapy and (b) perform quality control checks on linear accelerators. Methods and Materials: When imaging, our fluoroscopic EPID adjusts the gain, offset, and frame acquisition time of the charge coupled device (CCD) camera automatically, to allow for the range of photon transmissions through the patient, and to optimize the signal-to-noise ratio. However, our EPID can be programmed to act as an integrating dosemeter. EPID dosemeter measurements were made for 20 MV photons, for different field sizes and thicknesses of unit density phantom material placed at varying exit surface to detector distances. These were compared with simultaneous Silicon diode exit dose measurements. Our exit dosimetry technique was verified using an anthropomorphic type phantom, and some initial measurements have been made for patients treated with irregularly shaped 20 MV x-ray fields. In this dosimetry mode, our EPID was also used to measure certain quality control parameters, x-ray field flatness, and the verification of segmented intensity modulated field prescriptions. Results: Configured for dosimetry, our EPID exhibited a highly linear response, capable of resolving individual monitor units. Exit doses could be measured to within about 3% of that measured using Silicon diodes. Field flatness was determined to within 1.5% of Farmer dosemeter measurements. Segmented intensity modulated fields can be easily verified. Conclusions: Our EPID has the versatility to assess a range of parameters pertinent to the delivery of high quality, high precision radiotherapy. When configured appropriately, it can measure exit doses in vivo, with reasonable accuracy, perform certain quick quality control checks, and analyze segmented intensity modulated treatment fields

  4. EFFECT OF REVENUE INSURANCE ON ENTRY AND EXIT DECISIONS IN TABLE GRAPE PRODUCTION: A REAL OPTION APPROACH

    OpenAIRE

    Seo, Sangtaek; Salin, Victoria; Paul D Mitchell; Leatham, David J.

    2004-01-01

    This study determines the entry and exit thresholds of table grape farming with irreversible investment under uncertainty. Real option approach is adopted to consider the investment and management flexibility. Also revenue insurance is introduced to consider the effect of the risk management programs on the entry and exit thresholds. Results show that revenue insurance increases the entry and exit thresholds by 1% and 4%, respectively, thus discouraging new investment and current farming, as ...

  5. Exit points, on plasma, of lost fast ions during NBI in TJ-II

    International Nuclear Information System (INIS)

    The distribution of the exit points, on plasma border, for the lost fast ions during tangential balanced NBI in TJ-II helical axis Stellarator is theoretically analysed, as well for direct as for delayed losses. The link between the position of those exit points and the corresponding at birth, orbits and drifts is analysed also, it is shown that such relation is rather independent of beam energy and plasma density and is mainly related to the magnetic configuration characteristics. This study is a needed intermediate step to the analysis of impacts of those ions on the vacuum vessel of TJ-II

  6. Efficiency, Leverage and Exit: The Role of Information Asymmetry in Concentrated Industries

    DEFF Research Database (Denmark)

    Siyahhan, Baran

    2011-01-01

    This paper develops a real options model of imperfect competition with asymmetric information that analyzes firms’ exit decisions. Optimal exit decision is linked to firm characteristics such as financial leverage and efficiency. The model shows that informational asymmetries can lead more...... efficient and less leveraged firms to leave the product market prematurely. It also demonstrates how firm efficiency can increase debt capacity relative to rival firms. The model also has implications for firm risk and asset returns. Specifically, the paper shows that, when there is information asymmetry...

  7. Efficiency, Leverage and Exit: The Role of Information Asymmetry in Concentrated Industries

    DEFF Research Database (Denmark)

    Siyahhan, Baran

    This paper develops a real options model of imperfect competition with asymmetric information that analyzes firms’ exit decisions. Optimal exit decision is linked to firm characteristics such as financial leverage and efficiency. The model shows that informational asymmetries can lead more...... efficient and less leveraged firms to leave the product market prematurely. It also demonstrates how firm efficiency can increase debt capacity relative to rival firms. The model also has implications for firm risk and asset returns. Specifically, the paper shows that, when there is information asymmetry...

  8. Investigations in the degradation of polar and non-polar exit air constituents in biological scrubbers

    International Nuclear Information System (INIS)

    On a semi-technical scale (exit air volume flows between 1000 m3.h-1 and 3600 m3.h-1), experiments in the treatment of exit air from a mixed production plant of the chemical industry by biological absorption process were carried through. During testing, the configuration of the pilot plant was changed. Thus, both a multiple-zone nozzle scrubber and a packed column were used as an absorber, and as a scrubbing liquid both aerated sludge and a dispersion of aerated sludge and silicon oil with silicon oil contents of up to 5% wer used. (orig.)

  9. Fast Water Transport in CNTs: length dependence and entrane/exit effects

    DEFF Research Database (Denmark)

    Walther, Jens Honore; Koumoutsakos, Petros

    Superfast water transport in carbon nanotube (CNT) membranes has been reported in experimental studies. We use Molecular Dynamics simulations to elucidate the mechanisms of water entry, exit and transport in 2nm-diameter hydrophobic CNTs embedded in a hydrophilic membrane matrix. We demonstrate......, for the first time, that under imposed pressures of the order of 1 bar, water entry into the CNT cavity and exit from the CNT end, can occur only on pre-wetted membranes. We conduct large scale simulations for up to 500nm long CNTs and observe a previously unseen dependence of the flow enhancement...

  10. Determination of the availability of core exit thermocouples during severe accident situations

    International Nuclear Information System (INIS)

    This report presents the findings and recommendations of the Nuclear Power Plant Instrumentation Evaluation (NPPIE) program concerning signal validation methods to determine the on-line availability of core exit thermocouples during accident situations. Methods of selecting appropriate signal validation techniques are discussed and sources of error identified. This report shows that through the use of these techniques the existence of high-temperature-caused errors may be detected as they occur. Specific recommendations for application of selected signal validation techniques to core exit thermocouples and other measurement systems are made. 23 refs., 22 figs., 3 tabs

  11. High energy synchrotron X-ray focusing by fixed exit bender

    International Nuclear Information System (INIS)

    The performance of sagittal focusing for hard X-rays with a cylindrical bent crystal at SPring-8 is described. This bending mechanism is designed for the SPring-8 standard double crystal monochromator of bending-magnet beamlines. Therefore, a fixed height exit for a wide energy range (5-150 keV) is required. The results underline that focusing in a wide energy band was achieved by combining an adjustable inclined double crystal monochromator and a fixed height exit bending mechanism. The monochromator was maintained at a constant focus at the sample position by optimizing the bent crystal in the energy range from 60 to 150 keV

  12. Fluorescence method for enzyme analysis which couples aromatic amines with aromatic aldehydes

    Science.gov (United States)

    Smith, R.E.; Dolbeare, F.A.

    1980-10-21

    Analysis of proteinases is accomplished using conventional amino acid containing aromatic amine substrates. Aromatic amines such as 4-methoxy-2-naphthylamine (4M2NA), 2-naphthylamine, aminoisophthalic acid dimethyl ester, p-nitroaniline, 4-methoxy-1-aminofluorene and coumarin derivatives resulting from enzymatic hydrolysis of the substrate couples with aromatic aldehydes such as 5-nitrosalicylaldehyde (5-NSA), benzaldehyde and p-nitrobenzaldehyde to produce Schiff-base complexes which are water insoluble. Certain Schiff-base complexes produce a shift from blue to orange-red (visible) fluorescence. Such complexes are useful in the assay of enzymes. No Drawings

  13. Fluorescence method for enzyme analysis which couples aromatic amines with aromatic aldehydes

    Science.gov (United States)

    Smith, Robert E.; Dolbeare, Frank A.

    1979-01-01

    Analysis of proteinases is accomplished using conventional amino acid containing aromatic amine substrates. Aromatic amines such as 4-methoxy-2-naphthylamine (4M2NA), 2-naphthylamine, aminoisophthalic acid dimethyl ester, p-nitroaniline, 5-methoxy-1-aminofluorene and coumarin derivatives resulting from enzymatic hydrolysis of the substrate couples with aromatic aldehydes such as 5-nitrosalicylaldehyde (5-NSA), benzaldehyde and p-nitrobenzaldehyde to produce Schiff-base complexes which are water insoluble. Certain Schiff-base complexes produce a shift from blue to orange-red (visible) fluorescence. Such complexes are useful in the assay of enzymes.

  14. Polycyclic aromatic hydrocarbons in post-pyrogenic soils of drained peatlands in West Meshchera (Moscow Region, Russia)

    OpenAIRE

    A. S. Tsibart; A. N. Gennadiev; T. S. Koshovskii

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are priority pollutants and they arrive to the environment from numerous anthropogenic and natural sources, but the data on their natural sources which include wildfires remains insufficient. The level of contamination and the composition of PAHs in soils of the areas affected by wildfires were studied in this work. The study was conducted in Moscow Region (Russia) on the territories occupied with drained peatland and strongly damage...

  15. Polycyclic aromatic hydrocarbons in post-fire soils of drained peatlands in western Meshchera (Moscow region, Russia)

    OpenAIRE

    A. Tsibart; Gennadiev, A.; T. Koshovskii; Watts, A

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are priority pollutants that arrive in the environment from numerous anthropogenic and natural sources, but the data on their natural sources including wildfires remain insufficient. The level of contamination and the composition of PAHs in soils of the areas affected by wildfires were studied in this work. The study was conducted in the Moscow region (Russia) in areas occupied by drained peatland and strongly damaged by fires in 20...

  16. Concentrations, sources and spatial distribution of polycyclic aromatic hydrocarbons in soils from Beijing, Tianjin and surrounding areas, North China

    OpenAIRE

    Wang, Wentao; Massey Simonich, Staci L.; Xue, Miao; Zhao, Jingyu; Zhang, Na; Wang, Rong; Cao, Jun; Tao, Shu

    2010-01-01

    The concentrations, profiles, sources and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) were determined in 40 surface soil samples collected from Beijing, Tianjin and surrounding areas, North China in 2007, and all sampling sites were far from industrial areas, roadsides and other pollution sources, and across a range of soil types in remote, rural villages and urban areas. The total concentrations of 16 PAHs ranged from 31.6 to 1475.0 ng/g, with an arithmetic average of 336...

  17. Short Communication: Emission of Oxygenated Polycyclic Aromatic Hydrocarbons from Biomass Pellet Burning in a Modern Burner for Cooking in China

    OpenAIRE

    Shen, Guofeng; WEI, Siye; Zhang, Yanyan; Wang, Rong; Wang, Bin; Li, Wei; Shen, Huizhong; Ye HUANG; CHEN, Yuanchen; Chen, Han; Wei, Wen; Tao, Shu

    2012-01-01

    Biomass pellets are undergoing fast deployment widely in the world, including China. To this stage, there were limited studies on the emissions of various organic pollutants from the burning of those pellets. In addition to parent polycyclic aromatic hydrocarbons, oxygenated PAHs (oPAHs) have been received increased concerns. In this study, emission factors of oPAHs (EFoPAHs) were measured for two types of pellets made from corn straw and pine wood, respectively. Two combustion modes with (mo...

  18. Health Risk Assessment for Trace Metals, Polycyclic Aromatic Hydrocarbons and Trihalomethanes in Drinking Water of Cankiri, Turkey

    OpenAIRE

    Caylak, Emrah

    2012-01-01

    Lifetime exposure to trace metals, pesticides, polycyclic aromatic hydrocarbons (PAHs), trihalomethanes (THMs), and the other chemicals in drinking water through ingestion, and dermal contact may pose risks to human health. In this study, drinking water samples were collected from 50 sampling sites from Cankiri and its towns during 2010. The concentrations of all pollutants were analyzed, and then compared with permissible limits set by Turkish and WHO. For health risk assessment of trace met...

  19. Vehicular Traffic–Related Polycyclic Aromatic Hydrocarbon Exposure and Breast Cancer Incidence: The Long Island Breast Cancer Study Project (LIBCSP)

    OpenAIRE

    Mordukhovich, Irina; Beyea, Jan; Herring, Amy H.; Hatch, Maureen; Stellman, Steven D.; Teitelbaum, Susan L.; Richardson, David B; Millikan, Robert C.; Engel, Lawrence S; Shantakumar, Sumitra; Steck, Susan E.; Neugut, Alfred I; Rossner, Pavel; Santella, Regina M.; Gammon, Marilie D.

    2015-01-01

    Background Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants, known human lung carcinogens, and potent mammary carcinogens in laboratory animals. However, the association between PAHs and breast cancer in women is unclear. Vehicular traffic is a major ambient source of PAH exposure. Objectives Our study aim was to evaluate the association between residential exposure to vehicular traffic and breast cancer incidence. Methods Residential histories of 1,508 particip...

  20. Organo/LDH nanocomposite as an adsorbent of polycyclic aromatic hydrocarbons in water and soil-water systems

    OpenAIRE

    Bruna González, Felipe; de Celis, R; Real Ojeda, Miguel; Cornejo, J.

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are considered as priority pollutants because of their high risk to human health. In this paper, we addressed the issue of using hydrotalcite-based nanocomposites as adsorbents of six low molecular weight PAHs (acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene) to reduce their negative effects on the environment. A nanocomposite (HTDDS) was prepared by intercalating the organic anion dodecylsulfate (DDS) in a Mg¿Al hydrotalcite (...

  1. Molecular characterization of aromatic compound and heavy metal detoxification systems in thermophilic microorganisms: impact on biomonitoring and bioremediation.

    OpenAIRE

    Del Giudice, Immacolata

    2013-01-01

    Both arsenic and aromatic compounds are naturally present in the environment but human activities, such as the chemical and pharmaceutical industries, use of fossil fuels and pesticides, have contributed to their anomalous accumulation in the biosphere, determining severe damages to all living organisms. Many microorganisms possess tuned mechanisms for sensing the level of pollutants in their growth environment and controlling intracellular concentrations according to their biochemical needs....

  2. Biogeochemical processes governing exposure and uptake of organic pollutant compounds in aquatic organisms.

    OpenAIRE

    Farrington, J W

    1991-01-01

    This paper reviews current knowledge of biogeochemical cycles of pollutant organic chemicals in aquatic ecosystems with a focus on coastal ecosystems. There is a bias toward discussing chemical and geochemical aspects of biogeochemical cycles and an emphasis on hydrophobic organic compounds such as polynuclear aromatic hydrocarbons, polychlorinated biphenyls, and chlorinated organic compounds used as pesticides. The complexity of mixtures of pollutant organic compounds, their various modes of...

  3. Distribution of selected carcinogenic hydrocarbon and heavy metals in an oil-polluted agriculture zone

    OpenAIRE

    Nwaichi, E. O.; Wegwu, M. O.; Nwosu, U. L.

    2014-01-01

    Owing to the importance of clean and fertile agricultural soil for the continued existence of man, this study investigated the concentrations of total petroleum hydrocarbons (TPHs), polycyclic aromatic hydrocarbons (PAHs) and some heavy metals in soils and selected commonly consumed vegetables and tubers from oil-polluted active agricultural farmland in Gokana of Ogoniland, Rivers State, Nigeria. Samples from Umuchichi, Osisioma Local Government Area in Abia State, Nigeria, a non-oil-polluted...

  4. Application of Electro-Fenton Technology to Remediation of Polluted Effluents by Self-Sustaining Process

    OpenAIRE

    2014-01-01

    The applicability of electro-Fenton technology to remediation of wastewater contaminated by several organic pollutants such as dyes and polycyclic aromatic hydrocarbons has been evaluated using iron-enriched zeolite as heterogeneous catalyst. The electro-Fenton technology is an advanced oxidation process that is efficient for the degradation of organic pollutants, but it suffers from the high operating costs due to the need for power investment. For this reason, in this study microbial fuel c...

  5. Fate of hydrocarbon pollutants in source and non-source control sustainable drainage systems

    OpenAIRE

    Roinas, Georgios; Mant, Catherine; Williams, John B.

    2014-01-01

    Sustainable drainage (SuDs) is an established method for managing runoff from developments, and source control is part of accepted design philosophy. However, there are limited studies into the contribution source control makes to pollutant removal, especially for roads. This study examines organic pollutants, total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs), in paired source and non-source control full-scale SuDs systems. Sites were selected to cover local roads...

  6. Development of a screening method for the determination of total polynuclear aromatic hydrocarbons (PAH) in water and wastewater

    International Nuclear Information System (INIS)

    Polynuclear aromatic hydrocarbons (PAHs) represent an important class of organic compounds from an environmental standpoint, due to known human carcinogenicity of some members. Consequently, there is a great need for monitoring the PAH concentration of a variety of media, including water and industrial wastewater. Recently, the United States Environmental Protection Agency (U.S. EPA) developed a sensitive analytical method, designated Test Method 610, for the determination of priority pollutant PAHs in aqueous industrial discharges. This method employs reversed phase high performance liquid chromatography (HPLC) with ultraviolet (UV) and fluorescence detection to determine all sixteen priority pollutant PAHs in a single chromatographic separation

  7. Sediment baseline study of levels and sources of polycyclic aromatic hydrocarbons and heavy metals in Lake Nicaragua

    DEFF Research Database (Denmark)

    Scheibye, Katrine; Weisser, Johan; Borggaard, Ole K.;

    2014-01-01

    Selected metals and polycyclic aromatic hydrocarbons (PAHs) were analyzed in sediment samples from 24 sites in Lake Nicaragua sampled May 2010 to provide a baseline of pollution levels. Cu exceeded the Consensus-Based Sediment Quality Guideline (CBSQG) Threshold Effect Concentrations (TECs) at 21.......g., creosote). The main sources of PAHs in Lake Nicaragua were determined as of diffuse petrogenic and pyrogenic origin as well as diagenetic produced perylene. The relative importance of these PAH sources was determined by interpretation of loading and score plots from a principal component analysis. This...... study concluded that areas of Lake Nicaragua represent an important pollution baseline for future studies in this lake and other tropical lakes....

  8. A quantitative PCR approach for quantification of functional genes involved in the degradation of polycyclic aromatic hydrocarbons in contaminated soils.

    Science.gov (United States)

    Shahsavari, Esmaeil; Aburto-Medina, Arturo; Taha, Mohamed; Ball, Andrew S

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are major pollutants globally and due to their carcinogenic and mutagenic properties their clean-up is paramount. Bioremediation or using PAH degrading microorganisms (mainly bacteria) to degrade the pollutants represents cheap, effective methods. These PAH degraders harbor functional genes which help microorganisms use PAHs as source of food and energy. Most probable number (MPN) and plate counting methods are widely used for counting PAHs degraders; however, as culture based methods only count a small fraction (contaminated soil samples in few hours.•This protocol provides valuable information about the natural attenuation potential of contaminated soil and can be used to monitor the bioremediation process. PMID:27054096

  9. Fluorescent aromatic sensors and their methods of use

    Science.gov (United States)

    Meador, Michael A. (Inventor); Tyson, Daniel S. (Inventor); Ilan, Ulvi F. (Inventor)

    2012-01-01

    Aromatic molecules that can be used as sensors are described. The aromatic sensors include a polycyclic aromatic hydrocarbon core with a five-membered imide rings fused to the core and at least two pendant aryl groups. The aromatic sensor molecules can detect target analytes or molecular strain as a result of changes in their fluorescence, in many cases with on-off behavior. Aromatic molecules that fluoresce at various frequencies can be prepared by altering the structure of the aromatic core or the substituents attached to it. The aromatic molecules can be used as sensors for various applications such as, for example, the detection of dangerous chemicals, biomedical diagnosis, and the detection of damage or strain in composite materials. Methods of preparing aromatic sensor molecules are also described.

  10. Polycyclic Aromatic Hydrocarbons as Plausible Prebiotic Membrane Components

    OpenAIRE

    Groen, Joost; Deamer, David W.; Kros, Alexander; Ehrenfreund, Pascale

    2012-01-01

    Aromatic molecules delivered to the young Earth during the heavy bombardment phase in the early history of our solar system were likely to be among the most abundant and stable organic compounds available. The Aromatic World hypothesis suggests that aromatic molecules might function as container elements, energy transduction elements and templating genetic components for early life forms. To investigate the possible role of aromatic molecules as container elements, we incorporated different p...

  11. Electronic Aromaticity Index for Large Rings

    CERN Document Server

    Matito, Eduard

    2015-01-01

    We introduce a new electronic aromaticity index, AV1245, consisting in the average of the 4-center MCI values along the ring that keep a positional relationship of 1,2,4,5. AV1245 measures the extent of transferability of the delocalized electrons between bonds 1-2 and 4-5, which is expected to be large in conjugated circuits and, therefore, in aromatic molecules. A new algorithm for the calculation of MCI for large rings is also introduced and used to produce the data for the calibration of the new aromaticity index. AV1245 does not rely on reference values, does not suffer from large numerical precision errors, and it does not present any limitation on the nature of atoms, the molecular geometry or the level of calculation. It is a size-extensive measure with a small computational cost that grows linearly with the number of ring members. Therefore, it is specially suitable to study the aromaticity of large molecular rings as those occurring in belt-shaped M\\"obius structures or porphyrins.

  12. Extremely long aromatics: Diastereomerically pure [19]helicene

    Czech Academy of Sciences Publication Activity Database

    Nejedlý, Jindřich; Rybáček, Jiří; Stará, Irena G.; Starý, Ivo

    Praha: Czech Chemical Society, 2015. s. 119. [Liblice 2015. Advances in Organic , Bioorganic and Pharmaceutical Chemistry /50./. 06.11.2015-08.11.2015, Olomouc] R&D Projects: GA ČR(CZ) GA14-29667S Institutional support: RVO:61388963 Keywords : helically chiral aromatics * helicenes * [2+2+2] cycloisomerisation Subject RIV: CC - Organic Chemistry

  13. Aromatic cytokinins in micropropagated potato plants

    Czech Academy of Sciences Publication Activity Database

    Baroja, F. E.; Aguirreolea, J.; Martínková, Hana; Hanuš, Jan; Strnad, Miroslav

    2002-01-01

    Roč. 40, č. 3 (2002), s. 217-224. ISSN 0981-9428 R&D Projects: GA MŠk OC 844.10; GA ČR GA301/02/0475 Institutional research plan: CEZ:AV0Z5038910 Keywords : Acclimatization * Aromatic cytokinins * Micropropagation Subject RIV: CE - Biochemistry Impact factor: 1.582, year: 2002

  14. Discovering Chemical Aromaticity Using Fragrant Plants

    Science.gov (United States)

    Schneider, Tanya L.

    2010-01-01

    Introductory organic chemistry is often perceived as inaccessible by students. This article describes a method used to link organic chemistry to everyday experience, asking students to explore whether fragrant molecules are also aromatic in the chemical sense. Students were engaged in this activity, excited about their results, and performed well…

  15. Thermoset/Thermoplastic Aromatic Polyamides for Composites

    Science.gov (United States)

    St. Clair, T. L.; St. Clair, A. K.; Barrick, J. D.; Wolfe, J. F.; Greenwood, T. D.

    1983-01-01

    Aromatic polyamides are processed at relatively low temperature, then heat-treated to attain high softening temperature required when polyamides are used as matrix resins in structural composites. New polyamides are compatable with organic fibers often used as reinforcing agents in such composites Pendent propargyl groups serve as latent cross-linking agents in new series of polyamide resins.

  16. An electronic aromaticity index for large rings.

    Science.gov (United States)

    Matito, Eduard

    2016-04-28

    We introduce a new electronic aromaticity index, AV1245, consisting of an average of the 4-center multicenter indices (MCI) along the ring that keeps a positional relationship of 1, 2, 4, 5. AV1245 measures the extent of transferability of the delocalized electrons between bonds 1-2 and 4-5, which is expected to be large in conjugated circuits and, therefore, in aromatic molecules. A new algorithm for the calculation of MCI for large rings is also introduced and used to produce the data for the calibration of the new aromaticity index. AV1245 does not rely on reference values, does not suffer from large numerical precision errors, and it does not present any limitation on the nature of atoms, the molecular geometry or the level of calculation. It is a size-extensive measure with low computational cost that grows linearly with the number of ring members. Therefore, it is especially suitable to study the aromaticity of large molecular rings such as those occurring in belt-shaped Möbius structures or porphyrins. The analysis of AV1245 in free-base and bis-metalated Pd [32]octaphyrins(1,0,1,0,1,0,1,0) completes this study. PMID:26878146

  17. Fused aromatic thienopyrazines: structure, properties and function

    KAUST Repository

    Mondal, Rajib

    2010-01-01

    Recent development of a fused aromatic thieno[3.4-b]pyrazine system and their application in optoelectronic devices are reviewed. Introduction of a fused aromatic unit followed by side chain engineering, dramatically enhanced the charge carrier mobility in thin film transistor devices and mobilities up to 0.2 cm2/Vs were achieved. The optoelectronic properties of these fused aromatic thienopyrazine polymers (Eg = 1.3 to 1.6 eV, HOMO = -4.9 to -5.2 V) were tuned by introduction of various fused aromatic rings within thienopyrazine. By balancing the fundamental properties of these polymers, both high charge carrier mobilities and moderate PCEs in solar cells were achieved. Further, effects of copolymerizing units are discussed. Low band gap semiconducting polymer (Eg ∼ 1 eV) with high field effect mobility (0.044 cm2/Vs) was obtained using cyclopentadithiophene as copolymerizing unit. Finally, a molecular design approach to enhance the absorption coefficients is discussed, which resulted in improved power conversion efficiency in bulk heterojunction solar cells. © 2010 The Royal Society of Chemistry.

  18. Silicone elastomers with aromatic voltage stabilizers

    DEFF Research Database (Denmark)

    A Razak, Aliff Hisyam; Skov, Anne Ladegaard

    enhanced electrical breakdown strength due to delocalized pi-electrons of aromatic rings attached to the silicone backbone. The dielectric relative permittivity of PDMS-PPMS copolymers remained between 2 to3 with low conductivity and low dielectric loss as well as high storage moduli with low viscousloss...

  19. Dihydrodiol dehydrogenase and polycyclic aromatic hydrocarbon metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Smithgall, T.E.

    1986-01-01

    Carcinogenic activation of polycyclic aromatic hydrocarbons by microsomal monoxygenases proceeds through trans-dihydrodiol metabolites to diol-epoxide ultimate carcinogens. This thesis directly investigated the role of dihydrodiol dehydrogenase, a cytosolic NAD(P)-linked oxidoreductase, in the detoxification of polycyclic aromatic trans-dihydrodiols. A wide variety of non-K-region trans-dihydrodiols were synthesized and shown to be substrates for the homogeneous rat liver dehydrogenase, including several potent proximate carcinogens derived from 7,12-dimethylbenz(a)anthracene, 5-methylchrysene, and benzo(a)pyrene. Since microsomal activation of polycyclic aromatic hydrocarbons is highly stereospecific, the stereochemical course of enzymatic trans-dihydrodiol oxidation was monitored using circular dichroism spectropolarimetry. The major product formed from the dehydrogenase-catalyzed oxidation of the trans-1,2-dihydrodiol of naphthalene was characterized using UV, IR, NMR, and mass spectroscopy, and appears to be 4-hydroxy-1,2-naphthoquinone. Mass spectral analysis suggests that an analogous hydroxylated o-quinone is formed as the major product of benzo(a)pyrene-7,8-dihydrodiol oxidation. Enzymatic oxidation of trans-dihydrodiols was shown to be potently inhibited by all of the major classes of the nonsteroidal antiinflammatory drugs. Enhancement of trans-dihydrodiol proximate carcinogen oxidation may protect against possible adverse effects of the aspirin-like drugs, and help maintain the balance between activation and detoxification of polycyclic aromatic hydrocarbons.

  20. Exposures to Particulate Matter and Polycyclic Aromatic Hydrocarbons and Oxidative Stress in Schoolchildren

    OpenAIRE

    Bae, Sanghyuk; Pan, Xiao-Chuan; Kim, Su-Young; Park, Kwangsik; Kim, Yoon-Hee; Kim, Ho; Hong, Yun-Chul

    2009-01-01

    Background Air pollution is known to contribute to respiratory and cardiovascular mortality and morbidity. Oxidative stress has been suggested as one of the main mechanisms for these effects on health. Objective The aim of this study was to analyze the effects of exposure to particulate matter (PM) with aerodynamic diameters ≤ 10 μm (PM10) and ≤ 2.5 μm (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) on urinary malondialdehyde (MDA) levels in schoolchildren. Methods The study population co...