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Sample records for selected brominated flame

  1. Quantitative structure-activity relationship modeling on in vitro endocrine effects and metabolic stability involving 26 selected brominated flame retardants

    NARCIS (Netherlands)

    Harju, M.; Hamers, T.; Kamstra, J.H.; Sonneveld, E.; Boon, J.P.

    2007-01-01

    In this work, quantitative structure-activity relationships (QSARs) were developed to aid human and environmental risk assessment processes for brominated flame retardants (BFRs). Brominated flame retardants, such as the high-production-volume chemicals polybrominated diphenyl ethers (PBDEs),

  2. Selected chlorobornanes, polychlorinated naphthalenes and brominated flame retardants in Bjornoya (Bear Island) freshwater biota

    International Nuclear Information System (INIS)

    Evenset, Anita; Christensen, Guttorm N.; Kallenborn, Roland

    2005-01-01

    Levels of selected sparsely investigated persistent organic pollutants (POPs) have been measured in organisms from two Arctic lakes on Bjornoya (Bear Island). Elevated levels of chlorobornanes (CHBs) (up to 46.7 ng/g wet weight=ww), polybrominated diphenyl ethers (PBDEs) (up to 27.2 ng/g ww), polybrominated biphenyls (PBBs) (up to 1.1 ng/g ww) and polychlorinated naphthalenes (PCNs, only 4 congeners) (up to 62.7 pg/g ww), were measured in biota from Lake Ellasjoen. In Lake Oyangen, located only 5 km north of Ellasjoen, levels of these contaminants were significantly lower. δ 15 N-values were 7-10%o higher in organisms from Ellasjoen as compared to Oyangen. This is attributed to biological inputs related to seabird activities. The present study illustrates that contaminants such as CHBs, brominated flame retardants and PCNs accumulate in the Ellasjoen food web in a manner similar to PCBs and conventional organochlorine pesticides. Transport mechanisms that control PCB and DDT distributions, i.e. atmospheric long-range transport and biotransport by seabirds, are also relevant for the contaminants investigated in the present study. - Elevate levels of chlorobornanes, polychlorinated naphthalenes and brominated flame retardants have been measured in biota from a Norwegian Arctic lake

  3. Brominated and organophosphate flame retardants in selected consumer products on the Japanese market in 2008

    International Nuclear Information System (INIS)

    Kajiwara, Natsuko; Noma, Yukio; Takigami, Hidetaka

    2011-01-01

    Highlights: → We examined the flame retardants in electronics, curtains, wallpaper and insulator. → Use of alternative brominated and organophosphate flame retardants was suggested. → All the products investigated also contained PBDEs, TBBPA and polybromophenols. → Incorporation of recycled materials containing hazardous substance was suggested. - Abstract: The concentrations of traditional brominated flame retardants (BFRs) and organophosphate flame retardants (OPFRs) in new consumer products, including electronic equipment, curtains, wallpaper, and building materials, on the Japanese market in 2008 were investigated. Although some components of the electronic equipment contained bromine at concentrations on the order of percent by weight, as indicated by X-ray fluorescence analysis, the bromine content could not be fully accounted for by the BFRs analyzed in this study, which included polybrominated diphenylethers, decabromodiphenyl ethane, tetrabromobisphenol A, polybromophenols, and hexabromocyclododecanes. These results suggest the use of alternative BFRs such as newly developed formulations derived from tribromophenol, tetrabromobisphenol A, or both. Among the 11 OPFRs analyzed, triphenylphosphate was present at the highest concentrations in all the products investigated, which suggests the use of condensed-type OPFRs as alternative flame retardants, because they contain triphenylphosphate as an impurity. Tripropylphosphate was not detected in any samples; and trimethylphosphate, tributyl tris(2-butoxyethyl)phosphate, and tris(1,3-dichloro-2-propyl)phosphate were detected in only some components and at low concentrations. Note that all the consumer products evaluated in this study also contained traditional BFRs in amounts that were inadequate to impart flame retardancy, which implies the incorporation of recycled plastic materials containing BFRs that are of global concern.

  4. A, a Brominated Flame Retardant

    Directory of Open Access Journals (Sweden)

    Tomomi Takeshita

    2013-01-01

    Full Text Available Tetrabromobisphenol A (TBBPA, a brominated flame retardant, has been found to exacerbate pneumonia in respiratory syncytial virus- (RSV- infected mice. We examined the effect of Brazilian propolis (AF-08 on the exacerbation of RSV infection by TBBPA exposure in mice. Mice were fed a powdered diet mixed with 1% TBBPA alone, 0.02% AF-08 alone, or 1% TBBPA and 0.02% AF-08 for four weeks and then intranasally infected with RSV. TBBPA exposure increased the pulmonary virus titer and level of IFN-γ, a representative marker of pneumonia due to RSV infection, in the lungs of infected mice without toxicity. AF-08 was significantly effective in reducing the virus titers and IFN-γ level increased by TBBPA exposure. Also, AF-08 significantly reduced proinflammatory cytokine (TNF-α and IL-6 levels in the lungs of RSV-infected mice with TBBPA exposure, but Th2 cytokine (IL-4 and IL-10 levels were not evidently increased. Neither TBBPA exposure nor AF-08 treatment affected the anti-RSV antibody production in RSV-infected mice. In flow cytometry analysis, AF-08 seemed to be effective in reducing the ratio of pulmonary CD8a+ cells in RSV-infected mice with TBBPA exposure. TBBPA and AF-08 did not exhibit anti-RSV activity in vitro. Thus, AF-08 probably ameliorated pneumonia exacerbated by TBBPA exposure in RSV-infected mice by limiting excess cellular immune responses.

  5. Evaluation of long-range transport potential of selected brominated flame retardants with measured 1-octanol-air partition coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Jeong; Kwon, Jung Hwan [Div. of Environmental Science and Ecological Engineering, Korea University, Seoul (Korea, Republic of)

    2016-10-15

    Various alternative flame retardants are used in many countries since polybrominated diphenyl ethers (PBDEs) were classified as persistent organic pollutants (POPs). However, difficulties in the evaluation of the long-range transport potential (LRTP) of the alternatives are related to the lack of information on their physicochemical properties, which govern their environmental fates and transport. Based on the simulation of LRTP using OECD P{sub OV} and LRTP Screening Tool, five alternative brominated flame retardants (BFRs) (hexabromobenzene [HBB], 2,3,4,5,6-pentabromotoluene [PBT], 2,3,4,5,6-pentabromoethylbenzene [PBEB], 2-ethylhexyl 2,3,4,5-tetrabromobenzoate [TBB], and 1,2,4,5-tetrabromo-3,6-dimethylbenzene [TBX]), and 3 PBDEs (BDE-28, BDE-47, and BDE-99) were chosen to perform a refined assessment. This was done using an experimentally measured 1-octanol–air partition coefficient (K{sub OA}) for the calculation of the air–water partition coefficient (K{sub AW}) required for the model. The four selected alternative BFRs (HBB, PBT, PBEB, TBX) have K{sub OA} values close to the in silico estimation used in the screening evaluation. On the other hand, the measured K{sub OA} value for TBB was two orders of magnitude lower than the estimated value used in the screening simulation. The refined simulation showed that characteristic travel distance (CTD) and transfer efficiency (TE) for HBB, PBT, PBEB, and TBX were greater than those for BDE-28, whereas CTD and TE for TBB were lower than those for BDE-28. This suggested that TBB has a lower LRTP than BDE-28, considering the refined partition coefficients.

  6. Brominated flame retardants and endocrine disruption

    NARCIS (Netherlands)

    Vos, J.G.; Becher, G.; Berg, van den M.; Boer, de J.; Leonards, P.E.G.

    2003-01-01

    From an environmental point of view, an increasing important group of organohalogen compounds are the brominated flame retardants (BFRs), which are widely used in polymers and textiles and applied in construction materials, furniture, and electronic equipment. BFRs with the highest production volume

  7. Brominated flame retardants and endocrine disruption

    NARCIS (Netherlands)

    Vos, Joseph G.; Becher, Georg; Van Den Berg, Martin; Leonards, Pim E G

    2003-01-01

    From an environmental point of view, an increasing important group of organo-halogen compounds are the brominated flame retardants (BFRs), which are widely used in polymers and textiles and applied in construction materials, furniture, and electronic equipment. BFRs with the highest production

  8. Neurotoxicity of brominated flame retardants

    Science.gov (United States)

    Polybrominated diphenyl ethers (PBDEs) have been commonly used as commercial flame retardants in a variety of products including plastics and textiles. Despite their decreasing usage worldwide, congeners continue to accumulate in the environment, including soil, dust, food, anima...

  9. Brominated flame retardants: occurrence, dietary intake and risk assessment

    NARCIS (Netherlands)

    Winter-Sorkina R de; Bakker MI; Wolterink G; Zeijlmaker MJ; SIR

    2006-01-01

    Brominated flame retardants have entered the human food chain. For the time being the occurrence of these chemicals in Dutch food does not pose a human health risk. However, this might easily change at increasing contents of flame retardants in Dutch food. The monitoring of brominated flame

  10. Atmospheric Pressure Chemical Ionization Gas Chromatography Mass Spectrometry for the Analysis of Selected Emerging Brominated Flame Retardants in Foods

    Science.gov (United States)

    Lv, Surong; Niu, Yumin; Zhang, Jing; Shao, Bing; Du, Zhenxia

    2017-03-01

    Emerging brominated flame retardants (eBFRs) other than polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs) and their derivatives in foods have been in focus in recent years due to their increasing production volumes, indefinite information on toxicities and the lack of data on occurrence in environments, foods as well as humans. In this study, gas chromatography was coupled to an atmospheric pressure chemical ionization-tandem mass spectrometry (APGC-MS/MS) for the analysis of six eBFRs in pork, chicken, egg, milk and fish. A short section of unpacked capillary column coupled to the end of the analytical column was applied to improve the chromatographic behaviors of high boiling point compounds. The method was comprehensively validated with method limit of quantification (mLOQ) lower than 8 pg/g wet weight (w.w.). Samples from Chinese Total Diet study were quantified following the validated APGC-MS/MS method. 2,3,4,5-pentabromo-6-ethylbenzene (PBEB), hexabromobenzene (HBB), pentabromotoluene (PBT) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) were most frequently detected in samples. The highest concentration was found in fish with 351.9 pg/g w.w. of PBT. This is the first report on the presence of PBT in food samples with non-ignorable concentrations and detection rate.

  11. Atmospheric Pressure Chemical Ionization Gas Chromatography Mass Spectrometry for the Analysis of Selected Emerging Brominated Flame Retardants in Foods.

    Science.gov (United States)

    Lv, Surong; Niu, Yumin; Zhang, Jing; Shao, Bing; Du, Zhenxia

    2017-03-10

    Emerging brominated flame retardants (eBFRs) other than polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs) and their derivatives in foods have been in focus in recent years due to their increasing production volumes, indefinite information on toxicities and the lack of data on occurrence in environments, foods as well as humans. In this study, gas chromatography was coupled to an atmospheric pressure chemical ionization-tandem mass spectrometry (APGC-MS/MS) for the analysis of six eBFRs in pork, chicken, egg, milk and fish. A short section of unpacked capillary column coupled to the end of the analytical column was applied to improve the chromatographic behaviors of high boiling point compounds. The method was comprehensively validated with method limit of quantification (mLOQ) lower than 8 pg/g wet weight (w.w.). Samples from Chinese Total Diet study were quantified following the validated APGC-MS/MS method. 2,3,4,5-pentabromo-6-ethylbenzene (PBEB), hexabromobenzene (HBB), pentabromotoluene (PBT) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) were most frequently detected in samples. The highest concentration was found in fish with 351.9 pg/g w.w. of PBT. This is the first report on the presence of PBT in food samples with non-ignorable concentrations and detection rate.

  12. Recycling of plastic waste: Screening for brominated flame retardants (BFRs).

    Science.gov (United States)

    Pivnenko, K; Granby, K; Eriksson, E; Astrup, T F

    2017-11-01

    Flame retardants are chemicals vital for reducing risks of fire and preventing human casualties and property losses. Due to the abundance, low cost and high performance of bromine, brominated flame retardants (BFRs) have had a significant share of the market for years. Physical stability on the other hand, has resulted in dispersion and accumulation of selected BFRs in the environment and receiving biota. A wide range of plastic products may contain BFRs. This affects the quality of waste plastics as secondary resource: material recycling may potentially reintroduce the BFRs into new plastic product cycles and lead to increased exposure levels, e.g. through use of plastic packaging materials. To provide quantitative and qualitative data on presence of BFRs in plastics, we analysed bromophenols (tetrabromobisphenol A (TBBPA), dibromophenols (2,4- and 2,6-DBP) and 2,4,6-tribromophenol (2,4,6-TBP)), hexabromocyclododecane stereoisomers (α-, β-, and γ-HBCD), as well as selected polybrominated diphenyl ethers (PBDEs) in samples of household waste plastics, virgin and recycled plastics. A considerable number of samples contained BFRs, with highest concentrations associated with acrylonitrile butadiene styrene (ABS, up to 26,000,000ngTBBPA/g) and polystyrene (PS, up to 330,000ng∑HBCD/g). Abundancy in low concentrations of some BFRs in plastic samples suggested either unintended addition in plastic products or degradation of higher molecular weight BFRs. The presence of currently restricted flame retardants (PBDEs and HBCD) identified in the plastic samples illustrates that circular material flows may be contaminated for extended periods. The screening clearly showed a need for improved documentation and monitoring of the presence of BFRs in plastic waste routed to recycling. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Occurrence of brominated flame retardants in black thermo cups and selected kitchen utensils purchased on the European market.

    Science.gov (United States)

    Samsonek, J; Puype, F

    2013-01-01

    In order to screen for the presence of a recycled polymer waste stream from waste electric and electronic equipment (WEEE), a market survey was conducted on black plastic food-contact articles (FCA). An analytical method was applied combining X-ray fluorescence spectrometry (XRF) with thermal desorption gas chromatography coupled with mass spectrometry (thermal desorption GC-MS). Firstly, XRF spectrometry was applied to distinguish bromine-positive samples. Secondly, bromine-positive samples were submitted for identification by thermal desorption GC-MS. Generally, the bromine-positive samples contained mainly technical decabromodiphenyl ether (decaBDE). Newer types of BFRs such as tetrabromobisphenol A (TBBPA), tetrabromobisphenol A bis(2,3-dibromopropyl), ether (TBBPA-BDBPE) and decabromodiphenylethane (DBDPE), replacing the polybrominated diphenyleters (PBDEs) and polybrominated diphenyls (PBBs), were also identified. In none of the tested samples were PBBs or hexabromocyclododecane (HBCD) found. Polymer identification was carried out using Fourier-transformed infrared spectroscopy measurement (FTIR) on all samples. The results indicate that polypropylene-polyethylene copolymers (PP-PE) and mainly styrene-based food-contact materials, such as acrylonitrile-butadiene-styrene (ABS) have the highest risk of containing BFRs.

  14. Ecotoxicity and biodegradability of new brominated flame retardants: A review

    Czech Academy of Sciences Publication Activity Database

    Ezechiáš, Martin; Covino, Stefano; Cajthaml, Tomáš

    2014-01-01

    Roč. 110, č. 2 (2014), s. 153-167 ISSN 0147-6513 R&D Projects: GA MŠk(CZ) EE2.3.30.0003; GA TA ČR TE01020218 Institutional support: RVO:61388971 Keywords : Ecotoxicity * brominated flame retardants * biodegradation * review Subject RIV: EE - Microbiology, Virology Impact factor: 2.762, year: 2014

  15. The third international interlaboratory study on brominated flame retardants

    Energy Technology Data Exchange (ETDEWEB)

    Boer, J. de [Netherlands Institute for Fisheries Research, IJmuiden (Netherlands); Wells, D. [FRS Marine Laboratory, Aberdeen (United Kingdom)

    2004-09-15

    Polybrominated diphenyl ethers (PBDEs) have been produced as brominated flame retardants (BFRs) since the early 1970s and have been found in the aquatic environment since the late 1970s. However, as a result of their detection in sperm whales from deeper Atlantic waters and in human milk, many laboratories are now measuring PBDEs in environmental samples. A first international interlaboratory study (ILS) on the analysis of PBDEs, organised by the Bromine Science and Environmental Forum (BSEF), Brussels, Belgium, in collaboration with the Netherlands Institute for Fisheries Research (RIVO) was conducted in 1999-2000. The results showed that the 18 participating laboratories produced comparable results for BDE 47 in various matrices but had analytical difficulties for other BDEs, in particular for the BDEs 99 and 209. A second study was organised in 2001-2002 by BSEF, QUASIMEME and RIVO. That study showed improvement in comparability of the participating laboratories for BDE99 and some other BDEs. However, there was no improvement for BDE209. Hexabromocyclododecane (HBCD), tetrabromobisphenol-A (TBBP-A) and the dimethyl derivative of TBBP-A (dimethyl TBBP-A) were included in the second study. However, it appeared that only two or three laboratories were able to analyse these determinands. Others laboratories were still in the development phase with their methods for these BFRs. This third study was organised as a development exercise by QUASIMEME, in collaboration with RIVO between September and December 2003. The BFRs selected were the same as in the second study. Two biota test materials, a harbor sediment, a sewage sludge, and two standard solutions were dispatched to the participants.

  16. In vitro effects of selected brominated flame retardants on the adreno cortical enzyme (CYP17). A novel endocrine mechanism of action?

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Canton, R.; Sanderson, T.; Nijmeijer, S.; Berg, M. van den [Utrecht Univ. (NL). Inst. for Risk Assessment Sciences (IRAS); Berkman, Aa. [Stockholm Univ. (Sweden). Dept. of Environmental Chemistry and Analytical Chemistry

    2004-09-15

    Fire incidents have decreased over the last 20 years partly due to regulations requiring addition of flame retardants (FRs) to materials. These compounds can be divided into different chemical classes: inorganic, nitrogen, phosphorus and halogen containing flame retardants (usually brominated or chlorinated). Not surprisingly, the use of brominated flame retardants (BFRs) in a variety of commercial and household products has increased over the years due to their low cost and high effectiveness. Consequence of the high production of BFRs is that these compounds are now readily detectable in air, water, birds, fish, marine mammals, and in human adipose tissue and blood. The five major BFRs are hexabromocyclododecane (HBCD), tetrabromobisphenol-A (TBBPA) and three commercial mixtures of polybrominated diphenyl ethers (PBDEs) (penta, octa, deca), which are extensively used as FRs at high production volume levels. In addition, concentrations of PBDEs concentration have been rapidly increasing during the last 10 years in human breast milk from European and American women and a number of endocrine (in vitro) effects have been reported. Consequently, the concern about BFRs and their metabolites with respect to their potential as endocrine disruptors (EDs) has been growing. Studies in our laboratory are focused on potential interactions of a wide range of BFRs with sex hormone synthesis and metabolism. Previous results from our research group, showed inhibitory and inductive effects on aromatase (CYP19) (the key enzyme that converts androgens to estrogens) by certain BFRs, in particular the hydroxylated PBDEs and several bromophenols. In the present study, the effects of ten of these BFRs on CYP17 activity were investigated. This enzyme also catalyzes an important step in the sex steroidogenesis and is responsible for the biosynthesis of dehydroepiandrosterone (DHEA). DHEA, produced in the adrenal gland, is the most abundant sex steroid hormone in human blood and has been

  17. Pollution of Lake Mjoesa by brominated flame retardants

    Energy Technology Data Exchange (ETDEWEB)

    Schlabach, M.; Gundersen, H.; Mariussen, E. [NILU, Kjeller (Norway); Fjeld, E.; Breivik, E. [NIVA, Oslo (Norway); Kjellberg, G. [NIVA, Hamar (Norway)

    2004-09-15

    The worldwide use of brominated flame retardants (BFRs) is extensive and there are significant release of these components to the environment. The last twenty years the levels of the polybrominated diphenyl ethers (PBDE) in biota have increased, and in some areas the levels are comparable or even higher to what is reported for the polychlorinated biphenyls (PCB). This study was focused on the pollution of PBDEs in Lake Mjoesa, where unusually high concentrations have been found in fish. The objective of this part of the survey was to make a broader documentation of the PBDE levels in sediments and fish, and to localize areas with point sources of PBDEs.

  18. Catalytic degradation of brominated flame retardants by copper oxide nanoparticles

    Science.gov (United States)

    Dror, I.; Yecheskel, Y.; Berkowitz, B.

    2013-12-01

    Brominated flame retardants (BFRs) have been added to various products like plastic, textile, electronics and synthetic polymers at growing rates. In spite of the clear advantages of reducing fire damages, many of these BFRs may be released to the environment after their beneficial use which may lead to contamination of water resources. In this work we present the catalytic degradation of two brominated flame retardants (BFRs), tribromoneopentyl alcohol (TBNPA) and 2,4 dibromophenol (2,4-DBP) by copper oxide nanoparticles (nCuO) in aqueous solution. The degradation kinetics, the debromination, and the formation of intermediates by nCuO catalysis are compared to Fenton oxidation and to reduction by nano zero-valent iron (nZVI). The two studied BFRs are shown to degrade fully by the nCuO system within hours to days. Shorter reaction times showed differences in reaction pathways and kinetics for the two compounds. The 2,4-DBP showed faster degradation than TBNPA, by nCuO catalysis. Relatively high resistance to degradation was recorded for 2,4-DBP with nZVI, yielding 20% degradation after 24 h, while the TBNPA was degraded by 85% within 12 hours. A catalytic mechanism for radical generation and BFR degradation by nCuO is proposed. It is further suggested that H2O2 plays an essential role in the activation of the catalyst.

  19. Tracing organophosphorus and brominated flame retardants and plasticizers in an estuarine food web

    NARCIS (Netherlands)

    Brandsma, S.H.; Leonards, P.E.G.; Leslie, H.A.; de Boer, J.

    2015-01-01

    Nine organophosphorus flame retardants (PFRs) were detected in a pelagic and benthic food web of the Western Scheldt estuary, The Netherlands. Concentrations of several PFRs were an order of magnitude higher than those of the brominated flame retardants (BFRs). However, the detection frequency of

  20. Brominated flame retardants in Belgian little owl (Athene noctua) eggs

    Energy Technology Data Exchange (ETDEWEB)

    Jaspers, V.; Covaci, A.; Maervoet, J.; Dauwe, T.; Schepens, P.; Eens, M. [Antwerp Univ. (Belgium)

    2004-09-15

    Since the 1960s, polybrominated diphenylethers (PBDEs), a class of brominated flame retardants (BFRs), are widely used in textiles, plastics, electronic equipment and other materials. Their massive use has led to the ubiquitous presence of PBDEs in the environment and in biota in which the PBDE levels seem to increase rapidly. High concentrations of some congeners may cause adverse effects in both wildlife and in human populations1 and this has led to the growing concern of scientists over the last decade and to the need for more data on environmental levels of PBDEs. The little owl (Athene noctua) is a small sedentary predator, which makes it a very suitable biomonitoring species. This owl species feeds on a variety of preys, including small mammals and birds, reptiles, amphibians, earthworms and beetles, depending on the season and the local circumstances. Because very limited information is available about contamination levels in the little owl, a study was conducted to determine the concentrations of PBDEs, polybrominated biphenyls (PBBs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in deserted or addled eggs of little owls in Belgium. Eggs have been used successfully as a monitoring tool for persistent organic pollutants (POPs) in several studies. Although the analysis of POPs in deserted or addled eggs has clear limitations, these can be partially avoided by analysing only highly persistent components, for which the original composition will not change due to 'posthatching' microbiological degradation.

  1. Brominated flame retardants in Canadian chicken egg yolks.

    Science.gov (United States)

    Rawn, D F K; Sadler, A; Quade, S C; Sun, W-F; Lau, B P-Y; Kosarac, I; Hayward, S; Ryan, J J

    2011-06-01

    Chicken eggs categorised as conventional, omega-3 enriched, free range and organic were collected at grading stations in three regions of Canada between 2005 and 2006. Free run eggs, which were only available for collection from two regions, were also sampled during this time frame. Egg yolks from each of these egg types (n = 162) were analysed to determine brominated flame retardant levels, specifically polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD). PBDEs were detected in 100% of the 162 samples tested, while HBCD was observed in 85% of the egg yolks. Total PBDE concentrations in egg yolks ranged from 0.018 to 20.9 ng g(-1) lipid (median = 3.03 ng g(-1) lipid), with PBDE 209 identified as being the major contributor to ΣPBDE concentrations. In addition to PBDE 209, PBDE 99, 47, 100, 183 and 153 were important contributors to ΣPBDE concentrations. Total HBCD concentrations ranged from below the limit of detection to a maximum concentration of 71.9 ng g(-1) lipid (median = 0.053 ng g(-1) lipid). The α-isomer was the dominant contributor to ΣHBCD levels in Canadian egg yolks and was the most frequently detected HBCD isomer. ΣPBDE levels exhibited large differences in variability between combinations of region and type. ΣHBCD concentrations were not significantly different among regions, although differences were observed between the different types of egg yolks analysed in the present study.

  2. Human health risk associated with brominated flame-retardants (BFRs).

    Science.gov (United States)

    Lyche, Jan L; Rosseland, Carola; Berge, Gunnar; Polder, Anuschka

    2015-01-01

    The purposes of this review are to assess the human exposure and human and experimental evidence for adverse effects of brominated flame-retardants (BFRs) with specific focus on intake from seafood. The leakage of BFRs from consumer products leads to exposure of humans from fetal life to adulthood. Fish and fish products contain the highest levels of BFRs and dominate the dietary intake of frequent fish eaters in Europe, while meat, followed by seafood and dairy products accounted for the highest US dietary intake. House dust is also reported as an important source of exposure for children as well as adults. The levels of BFRs in the general North American populations are higher than those in Europe and Japan and the highest levels are detected in infants and toddlers. The daily intake via breast milk exceeds the RfD in 10% of US infants. BFRs including PBDEs, HBCDs and TBBP-A have induced endocrine-, reproductive- and behavior effects in laboratory animals. Furthermore, recent human epidemiological data demonstrated association between exposure to BFRs and similar adverse effects as observed in animal studies. Fish including farmed fish and crude fish oil for human consumption may contain substantial levels of BFRs and infants and toddlers consuming these products on a daily basis may exceed the tolerable daily intake suggesting that fish and fish oil alone represent a risk to human health. This intake comes in addition to exposure from other sources (breast milk, other food, house dust). Because potential harmful concentrations of BFRs and other toxicants occur in fish and fish products, research on a wider range of products is warranted, to assess health hazard related to the contamination of fish and fish products for human consumption. Copyright © 2014. Published by Elsevier Ltd.

  3. Particle size distribution of brominated flame retardants in house dust from Japan

    Directory of Open Access Journals (Sweden)

    Natsuko Kajiwara

    2016-06-01

    Full Text Available The present study was conducted to examine the concentrations, profiles, and mass distributions of polybrominated diphenyl ethers (PBDEs, hexabromocyclododecanes (HBCDs, and polybrominated dibenzo-p-dioxins/furans (PBDD/Fs based on the particle sizes of house dust samples from five homes in Japan. After removal of impurities from house dust from vacuum cleaner bags, selected indoor dust samples were size fractionated (>2 mm, 1–2 mm, 0.5–1 mm, 250–500 μm, 106–250 μm, 53–106 μm, and 250 μm in size and fluffy dust were included. The conclusion is that particulate dust <250 μm in size without fluffy dust should be used to analyze dust for brominated flame retardants.

  4. Brominated Flame Retardants and their metabolites: Novel insights into endocrine disruptive properties.

    NARCIS (Netherlands)

    Fernández Cantón, R.|info:eu-repo/dai/nl/304831530

    2008-01-01

    Brominated flame retardants (BFRs) are chemicals that are added to materials to inhibit or suppress ignition and are incorporated during the manufacture of e.g. electronic equipment, furniture, construction materials and textiles. BFRs have become an increasingly important group of organohalogen

  5. Detection of novel brominated flame retardants (NBFRs in the urban soils of Melbourne, Australia

    Directory of Open Access Journals (Sweden)

    Thomas J. McGrath

    2017-03-01

    Full Text Available A range of brominated flame retardants (BFRs have been incorporated into polymeric materials like plastics, electronic equipment, foams and textiles to prevent fires. The most common of these, polybrominated diphenyl ethers (PBDEs, have been subject to legislated bans and voluntary withdrawal by manufacturers in North America, Europe and Australia over the past decade due to long-range atmospheric transport, persistence in the environment, and toxicity. Evidence has shown that replacement novel brominated flame retardants (NBFRs are released to the environment by the same mechanisms as PBDEs and share similar hazardous properties. The objective of the current research was to characterize soil contamination by NBFRs in the urban soils of Melbourne, Australia. A variety of industrial and non-industrial land-uses were investigated with the secondary objective of determining likely point sources of pollution. Six NBFRs; pentabromotoluene (PBT, pentabromoethylbenzene (PBEB, hexabromobenzene (HBB, 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB, 1,2-bis(2,4,6-tribromophenoxyethane (BTBPE and decabromodiphenyl ethane (DBDPE were measured in 30 soil samples using selective pressurized liquid extraction (S-PLE and gas chromatography coupled to triple quadrupole mass spectrometry (GC-MS/MS. NBFRs were detected in 24/30 soil samples with Σ5NBFR concentrations ranging from nd-385 ng/g dw. HBB was the most frequently detected compound (14/30, while the highest concentrations were observed for DBDPE, followed by BTBPE. Electronic waste recycling and polymer manufacturing appear to be key contributors to NBFR soil contamination in the city of Melbourne. A significant positive correlation between Σ8PBDEs and Σ5NBFR soil concentrations was observed at waste disposal sites to suggest that both BFR classes are present in Melbourne's waste streams, while no association was determined among manufacturing sites. This research provides the first account of NBFRs

  6. Removal of brominated flame retardant from electrical and electronic waste plastic by solvothermal technique

    International Nuclear Information System (INIS)

    Zhang, Cong-Cong; Zhang, Fu-Shen

    2012-01-01

    Highlights: ► A process for brominated flame retardants (BFRs) removal in plastic was established. ► The plastic became bromine-free with the structure maintained after this treatment. ► BFRs transferred into alcohol solvent were easily debrominated by metallic copper. - Abstract: Brominated flame retardants (BFRs) in electrical and electronic (E and E) waste plastic are toxic, bioaccumulative and recalcitrant. In the present study, tetrabromobisphenol A (TBBPA) contained in this type of plastic was tentatively subjected to solvothermal treatment so as to obtain bromine-free plastic. Methanol, ethanol and isopropanol were examined as solvents for solvothermal treatment and it was found that methanol was the optimal solvent for TBBPA removal. The optimum temperature, time and liquid to solid ratio for solvothermal treatment to remove TBBPA were 90 °C, 2 h and 15:1, respectively. After the treatment with various alcohol solvents, it was found that TBBPA was finally transferred into the solvents and bromine in the extract was debrominated catalyzed by metallic copper. Bisphenol A and cuprous bromide were the main products after debromination. The morphology and FTIR properties of the plastic were generally unchanged after the solvothermal treatment indicating that the structure of the plastic maintained after the process. This work provides a clean and applicable process for BFRs-containing plastic disposal.

  7. Removal of brominated flame retardant from electrical and electronic waste plastic by solvothermal technique

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Cong-Cong [Research Center For Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Zhang, Fu-Shen, E-mail: fszhang@rcees.ac.cn [Research Center For Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China)

    2012-06-30

    Highlights: Black-Right-Pointing-Pointer A process for brominated flame retardants (BFRs) removal in plastic was established. Black-Right-Pointing-Pointer The plastic became bromine-free with the structure maintained after this treatment. Black-Right-Pointing-Pointer BFRs transferred into alcohol solvent were easily debrominated by metallic copper. - Abstract: Brominated flame retardants (BFRs) in electrical and electronic (E and E) waste plastic are toxic, bioaccumulative and recalcitrant. In the present study, tetrabromobisphenol A (TBBPA) contained in this type of plastic was tentatively subjected to solvothermal treatment so as to obtain bromine-free plastic. Methanol, ethanol and isopropanol were examined as solvents for solvothermal treatment and it was found that methanol was the optimal solvent for TBBPA removal. The optimum temperature, time and liquid to solid ratio for solvothermal treatment to remove TBBPA were 90 Degree-Sign C, 2 h and 15:1, respectively. After the treatment with various alcohol solvents, it was found that TBBPA was finally transferred into the solvents and bromine in the extract was debrominated catalyzed by metallic copper. Bisphenol A and cuprous bromide were the main products after debromination. The morphology and FTIR properties of the plastic were generally unchanged after the solvothermal treatment indicating that the structure of the plastic maintained after the process. This work provides a clean and applicable process for BFRs-containing plastic disposal.

  8. Prenatal Exposure to Organohalogens, Including Brominated Flame Retardants, Influences Motor, Cognitive, and Behavioral Performance at School Age

    NARCIS (Netherlands)

    Roze, Elise; Meijer, Lisethe; Bakker, Attie; Van Braeckel, Koenraad N. J. A.; Sauer, Pieter J. J.; Bos, Arend F.

    2009-01-01

    BACKGROUND: Organohalogen compounds (OHCs) are known to have neurotoxic effects on the developing brain. OBJECTIVE: We investigated the influence of prenatal exposure to OHCs, including brominated flame retardants, on motor, cognitive, and behavioral outcome in healthy children of school age.

  9. Category approach for selected brominated flame retardants

    DEFF Research Database (Denmark)

    Wedebye, Eva Bay; Nikolov, Nikolai Georgiev; Nielsen, Elsa Ebbesen

    Formålet med dette projekt var at undersøge muligheden for at gruppere bromerede flammehæmmere. 67 bromerede flammehæmmere blev inkluderet i undersøgelsen og grupperet på baggrund af deres kemiske strukturer, hvilket resulterede i 15 præliminære strukturelle grupper og 7 stoffer kategoriseret som...

  10. In vitro screening of the endocrine disrupting potency of brominated flame retardants and their metabolites

    Energy Technology Data Exchange (ETDEWEB)

    Hamers, T.; Kamstra, J.H. [Inst. for Environmental Studies (IVM), Amsterdam (Netherlands); Sonneveld, E. [BioDetection Systems (BDS), Amsterdam (Netherlands); Murk, A.J. [Wageningen Univ., Toxicology Group, Wageningen (Netherlands); Zegers, B.N.; Boon, J.P. [Royal Netherlands Inst. for Sea Research (NIOZ), Den Burg (Netherlands); Brouwer, A. [Umea Univ., Umea (Sweden)

    2004-09-15

    Substantial evidence is recently becoming available that brominated flame retardants (BFRs) are potential endocrine disruptors. The toxicological profile of BFRs, however, is too incomplete and insufficient to perform human and ecological risk assessment. To fill these gaps, the EU funded research program FIRE was started in December 2002. This program aims at the identification and toxicological characterization of the most potent and environmentally relevant BFRs and their possible risk for human and wildlife health. As part of a hazard identification approach, twenty seven BFRs have been selected within the framework of FIRE for pre-screening their endocrinedisrupting potencies. Selection of test compounds was based on a maximal variation in physicochemical characteristics of BFRs within the test set, allowing the establishment of quantitative structure-activity relationships (QSARs). In addition, environmental relevance (e.g. high production volumes and persistence) and availability for testing were used as selection criteria. BFRs were tested in seven different in vitro bioassays for their potency to interfere via estrogenic, thyroidal, androgenic, progestagenic, and Ah-receptor mediated pathways. Metabolisation rates of BFRs were determined using phenobarbital-induced rat liver microsomes. Finally, the endocrine disrupting potency of the metabolites was determined in the same in vitro bio-assays and compared to the potency of the parent compounds.

  11. Assessing oestrogenic effects of brominated flame retardants Hexabromocyclododecane and Tetrabromobisphenol A on MCF-7 cells

    Czech Academy of Sciences Publication Activity Database

    Dorosh, Andriy; Děd, Lukáš; Elzeinová, Fatima; Pěknicová, Jana

    2010-01-01

    Roč. 56, - (2010), s. 35-39 ISSN 0015-5500 R&D Projects: GA MŠk(CZ) 1M06011; GA MŠk(CZ) 2B06151 Institutional research plan: CEZ:AV0Z50520701 Keywords : endocrine disruptors * BRF - brominated flame retardant * MCF-7 cells * TFF1 - trefoil factor Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 0.729, year: 2010

  12. Characterization of brominated flame retardants in construction and demolition waste components: HBCD and PBDEs.

    Science.gov (United States)

    Duan, Huabo; Yu, Danfeng; Zuo, Jian; Yang, Bo; Zhang, Yukui; Niu, Yongning

    2016-12-01

    The vast majority of construction material is inert and can be managed as nonhazardous. However, structures may have either been built with some environmentally unfriendly substances such as brominated flame retardants (BFRs), or have absorbed harmful elements such as heavy metals. This study focuses on end-of-life construction materials, i.e. construction and demolition (C&D) waste components. The aim was to characterize the concentration of extremely harmful substances, primarily BFRs, including hexabromocyclododecane (HBCD) and polybrominateddiphenyl ethers (PBDEs). Results revealed extremely high contents of HBCD and PBDEs in typical C&D waste components, particularly polyurethane foam materials. Policies should therefore be developed for the proper management of C&D waste, with priority for POP-containing debris. The first priority is to develop a classification system and procedures to separate out the harmful materials for more extensive processing. Additionally, identification and quantification of the environmental implications associated with dumping-dominated disposal of these wastes are required. Finally, more sustainable materials should be selected for use in the construction industry. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. QSAR classification models for the prediction of endocrine disrupting activity of brominated flame retardants.

    Science.gov (United States)

    Kovarich, Simona; Papa, Ester; Gramatica, Paola

    2011-06-15

    The identification of potential endocrine disrupting (ED) chemicals is an important task for the scientific community due to their diffusion in the environment; the production and use of such compounds will be strictly regulated through the authorization process of the REACH regulation. To overcome the problem of insufficient experimental data, the quantitative structure-activity relationship (QSAR) approach is applied to predict the ED activity of new chemicals. In the present study QSAR classification models are developed, according to the OECD principles, to predict the ED potency for a class of emerging ubiquitary pollutants, viz. brominated flame retardants (BFRs). Different endpoints related to ED activity (i.e. aryl hydrocarbon receptor agonism and antagonism, estrogen receptor agonism and antagonism, androgen and progesterone receptor antagonism, T4-TTR competition, E2SULT inhibition) are modeled using the k-NN classification method. The best models are selected by maximizing the sensitivity and external predictive ability. We propose simple QSARs (based on few descriptors) characterized by internal stability, good predictive power and with a verified applicability domain. These models are simple tools that are applicable to screen BFRs in relation to their ED activity, and also to design safer alternatives, in agreement with the requirements of REACH regulation at the authorization step. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Distribution of copper, silver and gold during thermal treatment with brominated flame retardants

    International Nuclear Information System (INIS)

    Oleszek, Sylwia; Grabda, Mariusz; Shibata, Etsuro; Nakamura, Takashi

    2013-01-01

    Highlights: • Copper, silver and gold during thermal treatment with brominated flame retardants. • Distribution of copper, silver and gold during thermal processing. • Thermodynamic considerations of the bromination reactions. - Abstract: The growing consumption of electric and electronic equipment results in creating an increasing amount of electronic waste. The most economically and environmentally advantageous methods for the treatment and recycling of waste electric and electronic equipment (WEEE) are the thermal techniques such as direct combustion, co-combustion with plastic wastes, pyrolysis and gasification. Nowadays, this kind of waste is mainly thermally treated in incinerators (e.g. rotary kilns) to decompose the plastics present, and to concentrate metals in bottom ash. The concentrated metals (e.g. copper, precious metals) can be supplied as a secondary raw material to metal smelters, while the pyrolysis of plastics allows the recovery of fuel gases, volatilising agents and, eventually, energy. Indeed, WEEE, such as a printed circuit boards (PCBs) usually contains brominated flame retardants (BFRs). From these materials, hydrobromic acid (HBr) is formed as a product of their thermal decomposition. In the present work, the bromination was studied of copper, silver and gold by HBr, originating from BFRs, such as Tetrabromobisphenol A (TBBPA) and Tetrabromobisphenol A-Tetrabromobisophenol A diglycidyl ether (TTDE) polymer; possible volatilization of the bromides formed was monitored using a thermo-gravimetric analyzer (TGA) and a laboratory-scale furnace for treating samples of metals and BFRs under an inert atmosphere and at a wide range of temperatures. The results obtained indicate that up to about 50% of copper and silver can evolve from sample residues in the form of volatile CuBr and AgBr above 600 and 1000 °C, respectively. The reactions occur in the molten resin phase simultaneously with the decomposition of the brominated resin. Gold is

  15. Degradation of brominated flame retardant in computer housing plastic by supercritical fluids.

    Science.gov (United States)

    Wang, Yanmin; Zhang, Fu-Shen

    2012-02-29

    The degradation process of brominated flame retardant (BFR) and BFR-containing waste computer housing plastic in various supercritical fluids (water, methanol, isopropanol and acetone) was investigated. The results showed that the debromination and degradation efficiencies, final products were greatly affected by the solvent type. Among the four tested solvents, isopropanol was the most suitable solvent for the recovery of oil from BFR-containing plastic for its (1) excellent debromination effectiveness (debromination efficiency 95.7%), (2) high oil production (60.0%) and (3) mild temperature and pressure requirements. However, in this case, the removed bromine mostly existed in the oil. Introduction of KOH into the sc-isopropanol could capture almost all the inorganic bromine from the oil thus bromine-free oil could be obtained. Furthermore, KOH could enhance the depolymerization of the plastic. The obtained oil mainly consisted of single- and duplicate-ringed aromatic compounds in a carbon range of C9-C17, which had alkyl substituents or aliphatic bridges, such as butyl-benzene, (3-methylbutyl)-benzene, 1,1'-(1,3-propanediyl)bis benzene. Phenol, alkyl phenols and esters were the major oxygen-containing compounds in the oil. This study provides an efficient approach for debromination and simultaneous recovering valuable chemicals from BFR-containing plastic in e-waste. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Monitoring of WEEE plastics in regards to brominated flame retardants using handheld XRF

    Energy Technology Data Exchange (ETDEWEB)

    Aldrian, Alexia, E-mail: alexia.aldrian@unileoben.ac.at [Chair of Waste Processing Technology and Waste Management, Montanuniversitaet Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria); Ledersteger, Alfred, E-mail: a.ledersteger@saubermacher.at [Saubermacher Dienstleistungs AG, Hans-Roth-Straße 1, 8073 Feldkirchen bei Graz (Austria); Pomberger, Roland, E-mail: roland.pomberger@unileoben.ac.at [Chair of Waste Processing Technology and Waste Management, Montanuniversitaet Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria)

    2015-02-15

    Highlights: • Specification of an empirical factor for conversion from bromine to PBB and PBDE. • The handheld XRF device was validated for this particular application. • A very large number of over 4600 pieces of monitor housings was analysed. • The recyclable fraction mounts up to 85% for TV but only 53% of PC waste plastics. • A high percentage of pieces with bromine contents of over 50,000 ppm was obtained. - Abstract: This contribution is focused on the on-site determination of the bromine content in waste electrical and electronic equipment (WEEE), in particular waste plastics from television sets (TV) and personal computer monitors (PC) using a handheld X-ray fluorescence (XRF) device. The described approach allows the examination of samples in regards to the compliance with legal specifications for polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) directly after disassembling and facilitates the sorting out of plastics with high contents of brominated flame retardants (BFRs). In all, over 3000 pieces of black (TV) and 1600 pieces of grey (PC) plastic waste were analysed with handheld XRF technique for this study. Especially noticeable was the high percentage of pieces with a bromine content of over 50,000 ppm for TV (7%) and PC (39%) waste plastics. The applied method was validated by comparing the data of handheld XRF with results obtained by GC–MS. The results showed the expected and sufficiently accurate correlation between these two methods. It is shown that handheld XRF technique is an effective tool for fast monitoring of large volumes of WEEE plastics in regards to BFRs for on-site measurements.

  17. Brominated flame retardants and the formation of dioxins and furans in fires and combustion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Mengmei [State key laboratory of clean energy utilisation, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou (China); Buekens, Alfons [State key laboratory of clean energy utilisation, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou (China); Formerly with Chemical Engineering department, Vrije Universiteit Brussel, Brussels (Belgium); Li, Xiaodong, E-mail: lixd@zju.edu.cn [State key laboratory of clean energy utilisation, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou (China)

    2016-03-05

    Highlights: • BFRs (PBDEs, HBCD and TBBP-A) are the main sources of PBDD/Fs in combustion process. • Precursor formation is the most relevant pathway for PBDD/Fs formation. • Adding bromine into combustion system can enhance the formation of PCDD/Fs. • Primitive recycling of e-waste produces the largest amounts of PBDD/Fs. - Abstract: The widespread use and increasing inventory of brominated flame retardants (BFRs) have caused considerable concern, as a result of BFRs emissions to the environment and of the formation of both polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) and mixed polybromochloro-dibenzo-p-dioxins and dibenzofurans (PBCDD/Fs or PXDD/Fs). Structural similarities between PBDD/Fs and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) suggest the existence of comparable formation pathways of both PBDD/Fs and PCDD/Fs, yet BFRs also act as specific precursors to form additional PBDD/Fs. Moreover, elementary bromine (Br{sub 2}) seems to facilitate chlorination by bromination of organics, followed by Br/Cl-exchange based on displacement through the more reactive halogen. Overall, PBDD/Fs form through three possible pathways: precursor formation, de novo formation, and dispersion of parts containing BFRs as impurities and surviving a fire or other events. The present review summarises the formation mechanisms of both brominated (PBDD/Fs) and mixed dioxins (PXDD/Fs with X = Br or Cl) from BFRs, recaps available emissions data of PBDD/Fs and mixed PXDD/Fs from controlled waste incineration, uncontrolled combustion sources and accidental fires, and identifies and analyses the effects of several local factors of influence, affecting the formation of PBDD/Fs and mixed PXDD/Fs during BFRs combustion.

  18. Brominated flame retardants in end-of-life management not problematic regarding formation of brominated dioxins/furans (PBDD/F)

    Energy Technology Data Exchange (ETDEWEB)

    Drohmann, D. [Great Lakes Chemical, Bergisch Gladbach (Germany); Tange, L. [Eurobrom B.V., Rijswijk (Netherlands); Rothenbacher, K. [Bromine Science and Environmental Forum, Brussels (Belgium)

    2004-09-15

    Bromine is used as the building block for some of the most effective flame retarding agents available to the plastics industry today. They are used to protect against the risk of accidental fires in a wide range of products. Brominated flame retardants (BFRs), as all flame retardants, act to decrease the risk of fire by increasing the fire resistance of the materials in which they are applied. There is a perception that BFRs affect adversely the end-of-life management of plastics through formation of brominated dioxins and furans (PBDD/F). In fact, there exists a wide range of data and practical experience demonstrating that the end-of-life management of plastics containing BFRs are fully compliant with legislation setting the strictest limit values for PBDD/F and is fully compatible with an integrated waste management concept. Furthermore, all existing EU Risk Assessments on BFRs according to the European Existing Substance Regulations include an assessment of the potential formation of dioxins and furans. All assessments conclude that the risks along the life-cycle of the chemicals for human health and the environment associated with the potential formation of PBDD/F are negligible. Moreover, two recent Swedish studies found, that consumer products with BFRs emit less pollutants than the same products without any FRs. This paper summarises available studies and presents the latest results regarding potential formation of brominated dioxins and furans in end-of-life management of plastics containing brominated flame retardants. Additionally, before BFR products enter the market they are tested for PBDD/F according to the ''German Dioxin Ordinance''. Depending on the substitution pattern the limit values for PBDD/F are set at <1{mu}g/kg (ppb) respectively <5{mu}g/kg (ppb).

  19. Brominated flame retardants in black plastic kitchen utensils: Concentrations and human exposure implications.

    Science.gov (United States)

    Kuang, Jiangmeng; Abdallah, Mohamed Abou-Elwafa; Harrad, Stuart

    2018-01-01

    Concerns exist that restricted brominated flame retardants (BFRs) present in waste polymers may have, as a result of recycling, inadvertently contaminated items not required to meet flame retardancy regulations (e.g. plastic kitchen utensils). To investigate the extent to which kitchen utensils are contaminated with BFRs and the potential for resultant human exposure, we collected 96 plastic kitchen utensils and screened for Br content using a hand-held X-ray fluorescence (XRF) spectrometer. Only 3 out of 27 utensils purchased after 2011 contained detectable concentrations of Br (≥3μg/g). In contrast, Br was detected in 31 out of the 69 utensils purchased before 2011. Eighteen utensils with Br content higher than 100μg/g, and 12 new utensils were selected for GC-MS analysis of BFRs. BFRs targeted were polybrominated diphenyl ethers (PBDEs) BDE-28, 47, 99, 100, 153, 154, 183 and 209, and novel BFRs (NBFRs) pentabromoethylbenzene (PBEB), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (BEH-TEBP) and decabromodiphenyl ethane (DBDPE). The ability of XRF to act as a surrogate metric of BFR concentration was indicated by a significant (Spearman coefficient=0.493; p=0.006) positive relationship between Br and ΣBFR concentration. Measurements of ΣBFRs were always exceeded by those of Br. This may be due partly to the presence of BFRs not targeted in our study and also to reduced extraction efficiency of BFRs from utensils. Of our target BFRs, BDE-209 was the most abundant one in most samples, but an extremely high concentration (1000μg/g) of BTBPE was found in one utensil. Simulated cooking experiments were conducted to investigate BFR transfer from selected utensils (n=10) to hot cooking oil, with considerable transfer (20% on average) observed. Estimated median exposure via cooking with BFR contaminated utensils was 60ng/day for total BFRs. In contrast, estimated

  20. Terminal elimination half-lives of the brominated flame retardants TBBPA, HBCD, and lower brominated PBDEs in humans

    Energy Technology Data Exchange (ETDEWEB)

    Geyer, H.J.; Schramm, K.W.; Feicht, E.A.; Fried, K.W.; Henkelmann, B.; Lenoir, D. [GSF-National Research Center, Institute of Ecological Chemistry, Neuherberg (Germany); Darnerud, P.O.; Aune, M. [Swedish National Food Administration, Uppsala (Sweden); Schmid, P. [Swiss Federal Laboratories for Materials Testing and Research, Laboratory of Organic Chemistry, EMPA Duebendorf (Switzerland); McDonald, T.A. [Office of Environmental Health Assessment, California EPA, Oakland, CA (United States)

    2004-09-15

    Brominated flame retardants (BFRs) are widely used in polymers and textiles and applied in electronic equipment, construction materials, and furniture for the purpose of fire prevention. BFRs with the highest production volume are tetrabromobisphenol A (TBBPA), 1,2,5,6,9,10- hexabromocyclododecanes (HBCDs: {alpha}-HBCD + {beta}-HBCD + {gamma}-HBCD), and polybrominated diphenyl ethers (PBDEs). Several BFRs are highly lipophilic persistent organic pollutants (POPs) which have been identified in the aquatic and terrestrial environment including wildlife and humans. In exposed organisms including humans toxic effects, bioaccumulation, metabolism, and pharmacokinetics (especially half-life t{sub 1/2}) are important criterions in the hazard assessment. The aim of the present study was to estimate the terminal elimination half-lives (t{sub 1/2H}) of the main BFRs from the whole body (also named body-burden half-life) and/or from the adipose tissue (fat) of adult humans. The t{sub 1/2H} data for the following BFRs were evaluated: TBBPA, HBCD, 2,2',4,4'- tetrabromodiphenyl ether (BDE-47), 2,2',4,4',5-pentaBDE (BDE-99), 2,2',4,4',6-pentaBDE (BDE- 100), 2,2',4,4',5,5'-hexaBDE (BDE-153), and 2,2',4,4',5,6-hexaBDE (BDE-154).

  1. Associations between brominated flame retardants in house dust and hormone levels in men

    International Nuclear Information System (INIS)

    Johnson, Paula I.; Stapleton, Heather M.; Mukherjee, Bhramar; Hauser, Russ; Meeker, John D.

    2013-01-01

    Brominated flame retardants (BFRs) are used in the manufacture of a variety of materials and consumer products in order to meet fire safety standards. BFRs may persist in the environment and have been detected in wildlife, humans and indoor dust and air. Some BFRs have demonstrated endocrine and reproductive effects in animals, but human studies are limited. In this exploratory study, we measured serum hormone levels and flame retardant concentrations [31 polybrominated diphenyl ether (PBDE) congeners and 6 alternate flame retardants] in house dust from men recruited through a US infertility clinic. PBDE congeners in dust were grouped by commercial mixtures (i.e. penta-, octa- and deca-BDE). In multivariable linear regression models adjusted by age and body mass index (BMI), significant positive associations were found between house dust concentrations of pentaBDEs and serum levels of free T4, total T3, estradiol, and sex hormone binding globulin (SHBG), along with an inverse association with follicle stimulating hormone (FSH). There were also positive associations of octaBDE concentrations with serum free T4, thyroid stimulating hormone (TSH), luteinizing hormone (LH) and testosterone and an inverse association of decaBDE concentrations with testosterone. Hexabromocyclododecane (HBCD) was associated with decreased SHBG and increased free androgen index. Dust concentrations of bis-tribromophenoxyethane (BTBPE) and tetrabromo-diethylhexylphthalate (TBPH) were positively associated with total T3. These findings are consistent with our previous report of associations between PBDEs (BDE 47, 99 and 100) in house dust and hormone levels in men, and further suggest that exposure to contaminants in indoor dust may be leading to endocrine disruption in men. - Highlights: ► Brominated flame retardants (BFRs) including PBDEs and alternates were measured. ► Exposure to BFRs is characterized from concentrations in participant vacuum bag dust. ► Exposure to PBDEs and

  2. Associations between brominated flame retardants in house dust and hormone levels in men

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Paula I. [Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109 (United States); Stapleton, Heather M. [Nicholas School of the Environment, Box 90328, Duke University, Durham, NC 27708 (United States); Mukherjee, Bhramar [Department of Biostatistics, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109 (United States); Hauser, Russ [Department of Environmental Health, Harvard School of Public Health, 677 Huntington Ave., Boston, MA 02115 (United States); Meeker, John D., E-mail: meekerj@umich.edu [Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109 (United States)

    2013-02-15

    Brominated flame retardants (BFRs) are used in the manufacture of a variety of materials and consumer products in order to meet fire safety standards. BFRs may persist in the environment and have been detected in wildlife, humans and indoor dust and air. Some BFRs have demonstrated endocrine and reproductive effects in animals, but human studies are limited. In this exploratory study, we measured serum hormone levels and flame retardant concentrations [31 polybrominated diphenyl ether (PBDE) congeners and 6 alternate flame retardants] in house dust from men recruited through a US infertility clinic. PBDE congeners in dust were grouped by commercial mixtures (i.e. penta-, octa- and deca-BDE). In multivariable linear regression models adjusted by age and body mass index (BMI), significant positive associations were found between house dust concentrations of pentaBDEs and serum levels of free T4, total T3, estradiol, and sex hormone binding globulin (SHBG), along with an inverse association with follicle stimulating hormone (FSH). There were also positive associations of octaBDE concentrations with serum free T4, thyroid stimulating hormone (TSH), luteinizing hormone (LH) and testosterone and an inverse association of decaBDE concentrations with testosterone. Hexabromocyclododecane (HBCD) was associated with decreased SHBG and increased free androgen index. Dust concentrations of bis-tribromophenoxyethane (BTBPE) and tetrabromo-diethylhexylphthalate (TBPH) were positively associated with total T3. These findings are consistent with our previous report of associations between PBDEs (BDE 47, 99 and 100) in house dust and hormone levels in men, and further suggest that exposure to contaminants in indoor dust may be leading to endocrine disruption in men. - Highlights: ► Brominated flame retardants (BFRs) including PBDEs and alternates were measured. ► Exposure to BFRs is characterized from concentrations in participant vacuum bag dust. ► Exposure to PBDEs and

  3. Measurement and human exposure assessment of brominated flame retardants in household products from South China.

    Science.gov (United States)

    Chen, She-Jun; Ma, Yun-Juan; Wang, Jing; Tian, Mi; Luo, Xiao-Jun; Chen, Da; Mai, Bi-Xian

    2010-04-15

    Brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs), and decabromodiphenyl ethane (DBDPE) were examined in household products in the Pearl River Delta, South China, including electronic appliances, furniture and upholstery, car interiors, and raw materials for electronics. The concentrations of PBDEs derived from penta-BDE mixture were much lower (electronic products and their reuse might be also a potential important source of discontinued PBDEs to the environment. DBDPE was found in 20.0% of all the samples, ranging from 311 to 268,230 ng/g. PBDE congener profiles in both the household products and raw materials suggest that some less brominated BDEs in the environment may be derived from the decomposition of higher brominated PBDEs in PBDE-containing products in process of the manufacturing, use and/or recycling. Human exposure to PBDEs from household products via inhalation ranged from 175 to 612 pg/kg bw day, accounting for a small proportion of the total daily exposure via indoor inhalation. Despite the low deleterious risk associated with household products with regard to PBDEs, they are of special concern because of the relatively higher exposures observed for young children and further work is required. 2009 Elsevier B.V. All rights reserved.

  4. Measurement and human exposure assessment of brominated flame retardants in household products from South China

    Energy Technology Data Exchange (ETDEWEB)

    Chen Shejun [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Ma Yunjuan [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Zhuhai Environmental Moniorting Center, Zhuhai 519000 (China); Wang Jing; Tian Mi [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Luo Xiaojun [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Chen Da [Department of Environmental and Aquatic Animal Health, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062 (United States); Mai Bixian, E-mail: nancymai@gig.ac.cn [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2010-04-15

    Brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs), and decabromodiphenyl ethane (DBDPE) were examined in household products in the Pearl River Delta, South China, including electronic appliances, furniture and upholstery, car interiors, and raw materials for electronics. The concentrations of PBDEs derived from penta-BDE mixture were much lower (<111 ng/g) than those for octa- and deca-BDE commercially derived PBDEs, with maximum values of 15,107 and 1,603,343 ng/g, respectively, in all the household products. Our findings suggest the recycling of old electronic products and their reuse might be also a potential important source of discontinued PBDEs to the environment. DBDPE was found in 20.0% of all the samples, ranging from 311 to 268,230 ng/g. PBDE congener profiles in both the household products and raw materials suggest that some less brominated BDEs in the environment may be derived from the decomposition of higher brominated PBDEs in PBDE-containing products in process of the manufacturing, use and/or recycling. Human exposure to PBDEs from household products via inhalation ranged from 175 to 612 pg/kg bw day, accounting for a small proportion of the total daily exposure via indoor inhalation. Despite the low deleterious risk associated with household products with regard to PBDEs, they are of special concern because of the relatively higher exposures observed for young children and further work is required.

  5. Measurement and human exposure assessment of brominated flame retardants in household products from South China

    International Nuclear Information System (INIS)

    Chen Shejun; Ma Yunjuan; Wang Jing; Tian Mi; Luo Xiaojun; Chen Da; Mai Bixian

    2010-01-01

    Brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs), and decabromodiphenyl ethane (DBDPE) were examined in household products in the Pearl River Delta, South China, including electronic appliances, furniture and upholstery, car interiors, and raw materials for electronics. The concentrations of PBDEs derived from penta-BDE mixture were much lower (<111 ng/g) than those for octa- and deca-BDE commercially derived PBDEs, with maximum values of 15,107 and 1,603,343 ng/g, respectively, in all the household products. Our findings suggest the recycling of old electronic products and their reuse might be also a potential important source of discontinued PBDEs to the environment. DBDPE was found in 20.0% of all the samples, ranging from 311 to 268,230 ng/g. PBDE congener profiles in both the household products and raw materials suggest that some less brominated BDEs in the environment may be derived from the decomposition of higher brominated PBDEs in PBDE-containing products in process of the manufacturing, use and/or recycling. Human exposure to PBDEs from household products via inhalation ranged from 175 to 612 pg/kg bw day, accounting for a small proportion of the total daily exposure via indoor inhalation. Despite the low deleterious risk associated with household products with regard to PBDEs, they are of special concern because of the relatively higher exposures observed for young children and further work is required.

  6. Recycling of plastic waste: Screening for brominated flame retardants (BFRs)

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn; Granby, Kit; Eriksson, Eva

    2017-01-01

    ,4,6-TBP)), hexabromocyclododecane stereoisomers (α-, β-, and γ-HBCD), as well as selected polybrominated diphenyl ethers (PBDEs) in samples of household waste plastics, virgin and recycled plastics. A considerable number of samples contained BFRs, with highest concentrations associated with acrylonitrile...

  7. Accumulation of organochlorines and brominated flame retardants in estuarine and marine food chains: Field measurements and model calculations

    NARCIS (Netherlands)

    Veltman, K.; Hendriks, J.; Huijbregts, M.; Leonards, P.E.G.; Heuvel-Greve, van den M.J.; Vethaak, D.

    2005-01-01

    Food chain accumulation of organochlorines and brominated flame retardants in estuarine and marine environments is compared to model estimations and fresh water field data. The food chain consists of herbivores, detritivores and primary and secondary carnivores i.e. fish, fish-eating birds and

  8. Temporal Development of Brominated Flame Retardants in Peregrine Falcon (Falco peregrinus) Eggs from South Greenland (1986-2003)

    DEFF Research Database (Denmark)

    Vorkamp, K.; Thomsen, M.; Falk, K.

    2005-01-01

    A time trend between 1986 and 2003 was found for brominated flame retardants in peregrine falcon eggs from South Greenland, with significantly increasing concentrations of the polybrominated diphenyl ethers (PBDEs) 99, 100, 153, 154, and 209. For BDE-99 and -100, the concentration increased appro...

  9. A Novel Brominated Triazine-based Flame Retardant (TTBP-TAZ) in Plastic Consumer Products and Indoor Dust

    NARCIS (Netherlands)

    Ballesteros Gomez, A.M.; de Boer, J.; Leonards, P.E.G.

    2014-01-01

    The presence of a novel brominated flame retardant named 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ) is reported for the first time in plastic parts of consumer products and indoor dust samples. TTBP-TAZ was identified by untargeted screening and can be a replacement of the banned

  10. Concentrations of legacy and novel brominated flame retardants in indoor dust in Melbourne, Australia: An assessment of human exposure.

    Science.gov (United States)

    McGrath, Thomas J; Morrison, Paul D; Ball, Andrew S; Clarke, Bradley O

    2018-04-01

    Polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (NBFR) have been used in a range of polymers to inhibit the spread of fires but also have a propensity to migrate out of consumer materials and contaminate indoor dust. In this study, a total of 57 dust samples were collected from 12 homes, eight offices and eight vehicles in Melbourne, Australia and analysed for eight PBDEs (-28, -47, -99, -100, -153, -154, -183 and -209) and seven NBFRs (PBT, PBEB, HBB, EH-TBB, BEH-TEBP, BTBPE and DBDPE) to determine human exposure risks from dust ingestion. Samples were analysed using selective pressurized liquid extraction (S-PLE) and gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). Legacy and replacement flame retardants were detected in all samples with overall ∑PBDE concentrations ranging from 120 to 1700,000 ng/g (median 2100 ng/g) and ∑NBFRs ranging from 1.1 to 10,000 ng/g (median 1800 ng/g). BDE-209 and DBDPE were the dominant compounds in dust samples, followed by congeners associated with commercial Penta-BDE formulations (-47, -99, -100, -153 and -154) and then EH-TBB of the FireMaster 550 and BZ-54 products. ∑Penta-BDE concentrations were elevated in office samples compared with homes and vehicles, while EH-TBB and BDE-209 measured higher concentrations in vehicles compared with their respective levels in homes and offices. Risk assessment estimates revealed the majority of exposure to occur in the home for both adults and toddlers in the City of Melbourne. Generally, body weight adjusted exposure to PBDEs and NBFRs was predicted to be 1 to 2 orders of magnitude higher for toddlers than adults. Estimated rates of BDE-47, -99, -153 and -209 ingestion were each 2 orders of magnitude or more below the USEPA's prescribed oral reference dose values (RfDs) for typical exposure scenarios. However, exposure rates for BDE-47 and -99 reached as high as 52 and 95% of RfDs, respectively, for adults and 4.4 and 7

  11. Brominated flame retardants in Chinese air before and after the phase out of polybrominated diphenyl ethers

    Science.gov (United States)

    Li, Wen-Long; Qi, Hong; Ma, Wan-Li; Liu, Li-Yan; Zhang, Zhi; Mohammed, Mohammed O. A.; Song, Wei-Wei; Zhang, Zifeng; Li, Yi-Fan

    2015-09-01

    Brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs) and novel non-BDE flame retardants (NBFRs), were analyzed in Chinese air during China's POPs Soil and Air Monitoring Program Phase I (SAMP-I) and Phase II (SAMP-II). The levels of Σ12PBDEs and Σ6NBFRs in urban sites were significantly higher than those in rural sites and background sites. The higher detection rate and concentrations of high molecular weight PBDEs and NBFRs in Phase II indicated the changing of the commercial pattern of BFRs after the phase out of PBDEs in China. Temperature was the major factor affecting the seasonal variations of molecular weight BFRs in atmosphere. A significant correlation between BFRs concentration and gross domestic product (GDP) was observed, with the GDP parameter explained 59.4% and 72.7% of the total variability for Octa-BDEs and low molecular weight NBFRs, respectively. Our findings indicated an evolving commercial usage of BFRs from SAMP-I to SAMP-II, i.e. shifting from lower molecular weight to higher molecular weight congeners in China.

  12. Brominated flame retardants in children's toys: concentration, composition, and children's exposure and risk assessment.

    Science.gov (United States)

    Chen, She-Jun; Ma, Yun-Juan; Wang, Jing; Chen, Da; Luo, Xiao-Jun; Mai, Bi-Xian

    2009-06-01

    Brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), and polybrominated biphenyls (PBBs) were found in children's toys purchased from South China. The median BFR concentrations in the hard plastic toys were 53,000, 5540 ng/g, 101.1 ng/g, and 27.9 ng/g, fortotal PBDEs, DBDPE, BTBPE, and PBBs, respectively,which were notably higher than values in other toys. The PBDE concentrations were below the threshold limit (1000 ppm) required bythe European Commission's Restriction of Hazardous Substances (RoHS) and Waste Electrical and Electronic Equipment (WEEE) directives in all of the toys, except for one hard plastic toy with a total PBDE concentration of 5,344,000 ng/g. The BFR profiles in the toys were consistent with the patterns of their current production and consumption in China, where PBDEs, specifically decaBDE product, were the dominant BFR, followed by the emerging DBDPE. The relatively high concentrations of octa- and nonaBDEs in the foam toys and the results of principal component analysis (PCA) may suggest the decomposition of highly brominated BDEs during the manufacturing processes of the toys. Daily total PBDE exposures associated with toys via inhalation, mouthing, dermal contact, and oral ingestion ranged from 82.6 to 8992 pg/kg bw-day for children of 3 months to 14 years of age. Higher exposures, predominantly contributed through the mouthing pathway, were observed for infants and toddlers than for the other subgroups. In most cases, children's BFR exposure via the toys likely accounts for a small proportion of their daily BFR exposure, and the hazard quotients for noncancer risk evaluation were far below 1. To the author's knowledge, this is the first study to examine the concentrations of BFRs in toys, and the potential exposures to children.

  13. Characterization of brominated flame retardants from e-waste components in China.

    Science.gov (United States)

    Yu, Danfeng; Duan, Huabo; Song, Qingbin; Liu, Yicheng; Li, Ying; Li, Jinhui; Shen, Weijun; Luo, Jiahui; Wang, Jinben

    2017-10-01

    Many studies show that high levels of many toxic metals and persistent and bio-accumulative chemicals have been found in electronic waste (e-waste) dismantling sites and their surrounding environmental media. Both flame-retardant plastic housing materials and printed circuit boards (PCBs) could be the major contributors. However, relatively little work has focused on the use or content of toxic substances and their changing in scrap housing materials and PCBs from home appliances. This study evaluated the existence of brominated flame retardants (BFRs, including polybrominated diphenyl ethers (PBDEs) and Tetrabromobisphenol-A (TBBPA)) in housing plastics and PCBs from home appliances collected from various e-waste recyclers in China. These were then analyzed for the potential migration of BFRs from the e-waste components into their recycled products. The results show that both PBDEs and TBBPA were found with high level in most of e-waste samples, indicating that the widespread use of BFRs in home appliances are entering into the end-of-life stage. For the plastics samples, CRT TVs and LCD monitors should be given priority for the control of BFRs. Regarding PBDEs, the dominant congeners of BDE-209 in the plastics samples contributed 90.72-93.54% to the total concentrations of PBDEs, yet there are large variations for PCBs samples: BDE-28, -47, -99, and -153 were also important congeners compositions, except for BDE-209. Compared with previous studies, the BFRs concentrations in current Chinese e-waste are trending to decline. This study also found that BFRs in housing plastics and PCBs will be transferred into the recycled products with other purpose use, and the new products could have highly enriched capacities for BFRs. The obtained results could be helpful to manage e-waste and their components properly in order to minimize associated environmental and health risks of BFRs, particularly for their further reuse. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Modulation of human α4β2 nicotinic acetylcholine receptors by brominated and halogen-free flame retardants as a measure for in vitro neurotoxicity

    NARCIS (Netherlands)

    Hendriks, H.S.; van Kleef, R.G.D.M.; Westerink, R.H.S.

    2012-01-01

    Brominated flame retardants (BFRs) are abundant persistent organic pollutants with well-studied toxicity. The toxicological and ecological concern associated with BFRs argues for replacement by safer alternatives. However, the (neuro)toxic potential of alternative halogen-free flame retardants

  15. Soil contamination by brominated flame retardants in open waste dumping sites in Asian developing countries.

    Science.gov (United States)

    Eguchi, Akifimi; Isobe, Tomohiko; Ramu, Karri; Tue, Nguyen Minh; Sudaryanto, Agus; Devanathan, Gnanasekaran; Viet, Pham Hung; Tana, Rouch Seang; Takahashi, Shin; Subramanian, Annamalai; Tanabe, Shinsuke

    2013-03-01

    In Asian developing countries, large amounts of municipal wastes are dumped into open dumping sites each day without adequate management. This practice may cause several adverse environmental consequences and increase health risks to local communities. These dumping sites are contaminated with many chemicals including brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs). BFRs may be released into the environment through production processes and through the disposal of plastics and electronic wastes that contain them. The purpose of this study was to elucidate the status of BFR pollution in municipal waste dumping sites in Asian developing countries. Soil samples were collected from six open waste dumping sites and five reference sites in Cambodia, India, Indonesia, Malaysia, and Vietnam from 1999 to 2007. The results suggest that PBDEs are the dominant contaminants in the dumping sites in Asian developing countries, whereas HBCD contamination remains low. Concentrations of PBDEs and HBCDs ranged from ND to 180 μg/kg dry wt and ND to 1.4 μg/kg dry wt, respectively, in the reference sites and from 0.20 to 430 μg/kg dry wt and ND to 2.5 μg/kg dry wt, respectively, in the dumping sites. Contamination levels of PBDEs in Asian municipal dumping sites were comparable with those reported from electronic waste dismantling areas in Pearl River delta, China. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. A study of the presence of brominated flame retardants in Australian fauna

    Energy Technology Data Exchange (ETDEWEB)

    Symons, R.; Burniston, D.; Piro, N.; Stevenson, G.; Yates, A. [Australian Government Analytical Laboratories, Sydney (Australia)

    2004-09-15

    Brominated flame retardants, in particular polybrominated diphenyl ethers (PBDEs) gained prominence in the late nineties when Noren et al. reported an exponential increase in PBDE levels found in Swedish mothers milk over a quarter of a century period with an associated decrease in levels of dioxin-like compounds. PBDEs have since become exceptionally widely studied being detected in most environmental compartments and food as well as human tissues. Only limited information on the distribution if PBDEs is available for the Southern Hemisphere, however, elevated levels of PBDEs in pork fat were detected during the routine screening for organochlorine pesticide residues. More recently an investigation of breast milk for PBDE levels also demonstrated that levels were comparable with those in the Northern Hemisphere. BFRs are not manufactured in Australia but it has been estimated that over 500 tonnes are imported yearly of which 340 tonnes are PBDEs. In addition, the amount of PBDEs that are contained in imported articles used both in domestic and industrial applications is unknown. In this paper, we report levels of PBDEs in a range of different Australian fauna that show that these POPs have indeed become widely distributed both in terms of the types of the fauna but also the levels determined.

  17. Kinetics of Brominated Flame Retardant (BFR) Releases from Granules of Waste Plastics.

    Science.gov (United States)

    Sun, Bingbing; Hu, Yuanan; Cheng, Hefa; Tao, Shu

    2016-12-20

    Plastic components of e-waste contain high levels of brominated flame retardants (BFRs), whose releases cause environmental and human health concerns. This study characterized the release kinetics of polybrominated diphenyl ethers (PBDEs) from millimeter-sized granules processed from the plastic exteriors of two scrap computer displays at environmentally relevant temperatures. The release rate of a substitute of PBDEs, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), from the waste plastics, was reported for the first time. Deca-BDE was the most abundant PBDE congeners in both materials (87-89%), while BTBPE was also present at relatively high contents. The release kinetics of BFRs could be modeled as one-dimensional diffusion, while the temperature dependence of diffusion coefficients was well described by the Arrhenius equation. The diffusion coefficients of BFRs (at 30 °C) in the plastic matrices were estimated to be in the range of 10 -27.16 to 10 -19.96 m 2 ·s -1 , with apparent activation energies between 88.4 and 154.2 kJ·mol -1 . The half-lives of BFR releases (i.e., 50% depletion) from the plastic granules ranged from thousands to tens of billions of years at ambient temperatures. These findings suggest that BFRs are released very slowly from the matrices of waste plastics through molecular diffusion, while their emissions can be significantly enhanced with wear-and-tear and pulverization.

  18. BROMINATION OF 4-VINYLCYCLOHEXANE AND APPLYING THE RESULTING PRODUCT TO IMPROVE THE FLAME RETARDANT PROPERTIES OF WOOD

    Directory of Open Access Journals (Sweden)

    N. S. Nikulina

    2014-01-01

    Full Text Available Currently, the demand for timber is increasing. Wood and products on its basis are considered to be the most popular in the construction industry, furniture industry, as building materials and other However, along with the positive features of this material there are also negative factors, which include low resistance to biological degradation, high temperature, resistance. Wood and materials based on it are the most flammable, and fire safety is characterized by the velocity of propagation of fire on the wooden structure. He is able to destroy it in a matter of minutes. So the wooden house elements must be protected from fire. It was therefore necessary for the fire protection of wood. It is in the handling of wood with flame retardants. Basic fire fighting methods is the impregnation of wood antipyrene composition, painting fire paint and constructive ways - insulation of timber, non-combustible compositions which can resist the fire. In the work of brominated 4-vinylcyclohexane formed as a by-product in the petrochemical industry, in chloroform synthesized compound with bromine 62-64 % and the possibility of using this product to get antiferromag composition. It is established that the application for the protective treatment of wood synthesized flame retardant has shown that this product can be used for the protective treatment of natural wood to make it flame retardant properties. Use as antiperiodic compositions bromodomain based products 4-vinylcyclohexane allows to obtain images of wood first group of flame retardant efficiency.

  19. Differences in neonatal neurotoxicity of brominated flame retardants, PBDE 99 and TBBPA, in mice

    International Nuclear Information System (INIS)

    Viberg, Henrik; Eriksson, Per

    2011-01-01

    Highlights: → Neonatal exposure to PBDE 99, but not TBBPA, causes changes in the neonatal brain. → CaMKII increases in neonatal hippocampus after PBDE 99 exposure. → CaMKII, GAP-43 and synaptophysin increase in neonatal cortex after PBDE 99 exposure. → CaMKII increase in hippocampus has earlier been seen to proceed behavioral changes. → Neonatal exposure to PBDE 99, but not TBBPA, is known to cause behavioral deficits. -- Abstract: Flame retardants such as polybrominated diphenyl ethers (PBDE) and tetrabromobisphenol A are used as flame retardants and detected in the environmental, wildlife species and human tissues. Exposure to PBDEs during the neonatal development of the brain has been shown to affect behavior and learning and memory in adult mice, while neonatal exposure to TBBPA (another brominated flame retardant) did not affect behavioral variables in the adult. In this study, we hypothesized that the effects of these compounds could be reflected by changes in biochemical substrates and cholinergic receptors and have examined the levels of four proteins involved in maturation of the brain, neuronal growth and synaptogenesis and the densities of both muscarinic and nicotinic cholinergic receptors. We measured the levels of radioactivity in the brain after administration of 14 C-labelled TBBPA at different time points and saw that levels of TBBA peaked earlier and decreased faster than the earlier reported levels of PBDE 99. The protein analysis in the neonatal brain showed changes in the levels of calcium/calmodulin-dependent protein kinase II (CaMKII), growth associated protein-43 (GAP-43) and synaptophysin following neonatal exposure to PBDE 99 (21 μmol/kg body weight), but not following exposure TBBPA. Furthermore, neonatal exposure to PBDE 99 and TBBPA caused a decrease in binding sites of the nicotinic ligand cytisine in frontal cortex. These results confirm earlier reported data that PBDE 99 can act as a developmental neurotoxicant, possibly

  20. Brominated flame retardants in the Arctic environment--trends and new candidates.

    Science.gov (United States)

    de Wit, Cynthia A; Herzke, Dorte; Vorkamp, Katrin

    2010-07-01

    Polybrominated diphenyl ethers (PBDEs) containing two to 10 bromines are ubiquitous in the Arctic, in both abiotic and biotic samples. Hexabromocyclododecane (HBCD) is also ubiquitous in the Arctic, with the gamma-HBCD isomer predominating in air, the alpha-HBCD isomer predominating in biota and similar concentrations of alpha-, beta- and gamma-HBCD found in marine sediments. Other brominated flame retardants (BFRs) found in some Arctic samples are polybrominated biphenyls (PBBs), tetrabromobisphenol A (TBBPA), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), hexabromobenzene (HxBBz), pentabromoethylbenzene (PBEB), pentabromotoluene (PBT), and 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH). Temporal trends of tetra- to heptaBDEs and HBCD show increasing concentrations or a tendency to levelling off depending on the matrix (air, sediment, biota) and location, but no uniform picture for the Arctic emerges. BDE-209 concentrations are increasing in air. PBDEs and HBCD spatial trends in seabirds and marine mammals are similar to those seen previously for polychlorinated biphenyls (PCBs), with highest concentrations found in organisms from East Greenland and Svalbard. These trends indicate western Europe and eastern North America as important source regions of these compounds via long range atmospheric transport and ocean currents. Latitudinal trends showed lower concentrations and fluxes of PBDEs at higher latitudes. The tetra-hexaBDEs and alpha-HBCD biomagnify in Arctic food webs. Results for BDE-209 are more conflicting, showing either only low or no biomagnification potential. PBDE and HBCD concentrations are lower in terrestrial organisms and higher in marine top predators such as some killer whale populations in Alaska and glaucous gulls from the Barents Sea area. Higher concentrations are seen near populated areas indicating local sources. Findings of BTBPE, HxBBz, PBEB, PBT and TBECH in seabirds and/or marine mammals indicate that these compounds reach the

  1. Brominated flame retardants in the Arctic. An overview of spatial and temporal trends

    Energy Technology Data Exchange (ETDEWEB)

    Wit, C de [Institute of Applied Environmental Research, Stockholm (Sweden); Alaee, M; Muir, D [National Water Research Institute, Burlington, MA (United States)

    2004-09-15

    The Stockholm Convention on Persistent Organic Pollutants (POPs), which entered into force on May 17, 2004, includes wording that chemicals with the characteristics of POPs are those found in locations ''distant from sources'' and those for which ''monitoring data showing that long-range environmental transport of the chemical may have occurred''. Thus, the Arctic has become an important indicator region for assessment of persistence and bioaccumulation. The Arctic environment is well suited as a region in which to evaluate POPs. Some regions of thee Arctic, particularly the Barents Sea area north of Norway and western Russia are relatively close to source regions of POPs. Cold conditions favor persistence of POPs relative to temperate or tropical environments. The presence of fourth level carnivores (e.g. polar bears and seabirds), and storage of lipid as an energy source, make Arctic food webs vulnerable to bioaccumulative chemicals. Indigenous people in the Arctic utilizing a traditional diet, which is high in nutritionally beneficial fat, results in their elevated exposure to some POPs. The first indication that brominated flame retardants (BFRs) were reaching the Arctic was the detection by Jansson et al. of lower molecular weight polybrominated diphenyl ethers (PBDEs) in Svalbard Brunnichfs guillemots (130 ng/g lipid weight) and ringed seals (40 ng/g lw) collected in 1981. Whitefish collected from Lake Storvindeln in 1986, a pristine mountain lake in the Swedish mountains near Ammarnas, had {sigma}PBDE levels of 26 ng/g lw. Despite these early findings, only recently have the spatial and temporal trends of BFRs been studied in detail in the Arctic. The purpose of this paper is to review the new data on BFRs in the Arctic and assess whether this information supports the view that PBDEs and other BFRs of similar molecular weight are POPs and potential global pollutants. This review is based on a recent assessment of POPs in the Arctic combined with newer data

  2. Brominated flame retardants in the Arctic. An overview of spatial and temporal trends

    Energy Technology Data Exchange (ETDEWEB)

    Wit, C. de [Institute of Applied Environmental Research, Stockholm (Sweden); Alaee, M.; Muir, D. [National Water Research Institute, Burlington, MA (United States)

    2004-09-15

    The Stockholm Convention on Persistent Organic Pollutants (POPs), which entered into force on May 17, 2004, includes wording that chemicals with the characteristics of POPs are those found in locations ''distant from sources'' and those for which ''monitoring data showing that long-range environmental transport of the chemical may have occurred''. Thus, the Arctic has become an important indicator region for assessment of persistence and bioaccumulation. The Arctic environment is well suited as a region in which to evaluate POPs. Some regions of thee Arctic, particularly the Barents Sea area north of Norway and western Russia are relatively close to source regions of POPs. Cold conditions favor persistence of POPs relative to temperate or tropical environments. The presence of fourth level carnivores (e.g. polar bears and seabirds), and storage of lipid as an energy source, make Arctic food webs vulnerable to bioaccumulative chemicals. Indigenous people in the Arctic utilizing a traditional diet, which is high in nutritionally beneficial fat, results in their elevated exposure to some POPs. The first indication that brominated flame retardants (BFRs) were reaching the Arctic was the detection by Jansson et al. of lower molecular weight polybrominated diphenyl ethers (PBDEs) in Svalbard Brunnichfs guillemots (130 ng/g lipid weight) and ringed seals (40 ng/g lw) collected in 1981. Whitefish collected from Lake Storvindeln in 1986, a pristine mountain lake in the Swedish mountains near Ammarnas, had {sigma}PBDE levels of 26 ng/g lw. Despite these early findings, only recently have the spatial and temporal trends of BFRs been studied in detail in the Arctic. The purpose of this paper is to review the new data on BFRs in the Arctic and assess whether this information supports the view that PBDEs and other BFRs of similar molecular weight are POPs and potential global pollutants. This review is based on a recent assessment of POPs

  3. Dehydrohalogenation during pyrolysis of brominated flame retardant containing high impact polystyrene (HIPS-Br) mixed with polyvinylchloride (PVC)

    Energy Technology Data Exchange (ETDEWEB)

    Uddin, M.A.; Bhaskar, T.; Kaneko, J.; Muto, A.; Sakata, Y.; Matsui, T. [Okayama University, Okayama (Japan). Dept. of Applied Chemistry, Faculty of Engineering

    2002-09-01

    Dehydrohalogenation during pyrolysis of brominated flame retardant containing polystyrene (brominated high impact polystyrene (HIPS-Br)) mixed with polyvinylchloride (PVC) was carried out in a laboratory scale batch process. Thermal and catalytic degradation of HIPS-Br mixed with PVBC on carbon composite of iron oxide (TR-00301) catalyst was investigated. The thermal degradation of waste plastics (HIPS-Br/PVC) yielded liquid products with 55,000 ppm bromine and 4300 ppm chlorine content in oil. Catalytic degradation (4 g; TR-00301) of HIPS-Br/PVC waste plastics at 430{degree}C produced halogen-free clean oil, which can be used as a fuel oil or chemical feedstock. The main liquid products during catalytic degradation were benzene, toluene, styrene, ethyl benzene, {alpha}-methyl styrene, butyl benzene, 1,2-dimethyl benzene etc. The average carbon number of the liquid products produced during catalytic degradation (9.3) of waste plastics was less than that of the thermal degradation (10.4) and the density of liquid products was found to be lower during the catalytic degradation than the thermal degradation. The possibility of a single step catalytic process for the conversion of halogenated waste plastics into fuel oil with the simultaneous removal of chlorine and bromine content form the oil was demonstrated. 21 refs., 7 figs., 2 tabs.

  4. Tracing organophosphorus and brominated flame retardants and plasticizers in an estuarine food web.

    Science.gov (United States)

    Brandsma, Sicco H; Leonards, Pim E G; Leslie, Heather A; de Boer, Jacob

    2015-02-01

    Nine organophosphorus flame retardants (PFRs) were detected in a pelagic and benthic food web of the Western Scheldt estuary, The Netherlands. Concentrations of several PFRs were an order of magnitude higher than those of the brominated flame retardants (BFRs). However, the detection frequency of the PFRs (6-56%) was lower than that of the BFRs (50-97%). Tris(2-butoxyethyl) phosphate (TBOEP), tris(isobutyl) phosphate (TIBP) and tris(2-chloroisopropyl) phosphate (TCIPP) were the dominant PFRs in sediment with median concentrations of 7.0, 8.1 and 1.8 ng/g dry weight (dw), respectively. PFR levels in the suspended particular matter (SPM) were 2-12 times higher than that in sediment. TBOEP, TCIPP, TIBP, tris(2-chloroethyl) phosphate (TCEP) and tris(phenyl) phosphate (TPHP) were found in organisms higher in the estuarine food web. The highest PFR concentrations in the benthic food web were found in sculpin, goby and lugworm with median concentrations of 17, 7.4, 4.6 and 2.0 ng/g wet weight (ww) for TBOEP, TIBP, TCIPP and TPHP, respectively. Comparable levels were observed in the pelagic food web, BDE209 was the predominant PBDE in sediment and SPM with median concentrations up to 9.7 and 385 ng/g dw, respectively. BDE47 was predominant in the biotic compartment of the food web with highest median levels observed in sculpin and common tern eggs of 79 ng/g lipid weight (lw) (2.5 ng/g ww) and 80 ng/g lw (11 ng/g ww), respectively. Trophic magnification was observed for all PBDEs with the exception of BDE209. Indications of trophic magnification of PFRs were observed in the benthic food web for TBOEP, TCIPP and TCEP with tentative trophic magnification factors of 3.5, 2.2 and 2.6, respectively (pwebs. The relative high PFR levels in several fish species suggest high emissions and substantial exposure of organisms to PFRs in the Western Scheldt. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Airborne particle-bound brominated flame retardants: Levels, size distribution and indoor-outdoor exchange.

    Science.gov (United States)

    Zhu, Yue-Shan; Yang, Wan-Dong; Li, Xiu-Wen; Ni, Hong-Gang; Zeng, Hui

    2018-02-01

    The quality of indoor environments has a significant impact on public health. Usually, an indoor environment is treated as a static box, in which physicochemical reactions of indoor air contaminants are negligible. This results in conservative estimates for primary indoor air pollutant concentrations, while also ignoring secondary pollutants. Thus, understanding the relationship between indoor and outdoor particles and particle-bound pollutants is of great significance. For this reason, we collected simultaneous indoor and outdoor measurements of the size distribution of airborne brominated flame retardant (BFR) congeners. The time-dependent concentrations of indoor particles and particle-bound BFRs were then estimated with the mass balance model, accounting for the outdoor concentration, indoor source strength, infiltration, penetration, deposition and indoor resuspension. Based on qualitative observation, the size distributions of ΣPBDE and ΣHBCD were characterized by bimodal peaks. According to our results, particle-bound BDE209 and γ-HBCD underwent degradation. Regardless of the surface adsorption capability of particles and the physicochemical properties of the target compounds, the concentration of BFRs in particles of different size fractions seemed to be governed by the particle distribution. Based on our estimations, for airborne particles and particle-bound BFRs, a window-open ventilated room only takes a quarter of the time to reach an equilibrium between the concentration of pollutants inside and outside compared to a closed room. Unfortunately, indoor pollutants and outdoor pollutants always exist simultaneously, which poses a window-open-or-closed dilemma to achieve proper ventilation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Maternal transfer of emerging brominated and chlorinated flame retardants in European eels

    Energy Technology Data Exchange (ETDEWEB)

    Sühring, Roxana, E-mail: roxana.suehring@hzg.de [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Coastal Research, Department for Environmental Chemistry, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Leuphana University Lüneburg, Institute of Sustainable and Environmental Chemistry, Scharnhorststraße 1, 21335 Lüneburg (Germany); Freese, Marko [Thünen Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg (Germany); Schneider, Mandy [Leuphana University Lüneburg, Institute of Sustainable and Environmental Chemistry, Scharnhorststraße 1, 21335 Lüneburg (Germany); Schubert, Sophia; Pohlmann, Jan-Dag [Thünen Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg (Germany); Alaee, Mehran [Water Science and Technology Directorate, Environment Canada, Burlington, Ontario, L7R4A6 Canada (Canada); Wolschke, Hendrik [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Coastal Research, Department for Environmental Chemistry, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Leuphana University Lüneburg, Institute of Sustainable and Environmental Chemistry, Scharnhorststraße 1, 21335 Lüneburg (Germany); Hanel, Reinhold [Thünen Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg (Germany); Ebinghaus, Ralf [Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Coastal Research, Department for Environmental Chemistry, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Marohn, Lasse [Thünen Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg (Germany)

    2015-10-15

    The European eel (Anguilla anguilla) is regarded as a critically endangered species. Scientists are in agreement that the “quality of spawners” is a vital factor for the survival of the species. This quality can be impaired by parasites, disease and pollution. Especially endocrine disrupting organic chemicals pose a potential threat to reproduction and development of offspring. To our knowledge, the findings in this publication for the first time describe maternal transfer of contaminants in eels. We analysed the concentrations of in total 53 polybrominated diphenyl ethers (PBDEs) and their halogenated substitutes in muscle, gonads and eggs of artificially matured European eels and in muscle and gonads of untreated European eels that were used for comparison. We found evidence that persistent organic pollutants such as PBDEs, as well as their brominated and chlorinated substitutes are redistributed from muscle tissue to gonads and eggs. Concentrations ranged from 0.001 ng g{sup −1} ww for sum Dechlorane metabolites (DPMA, aCL{sub 10}DP, aCl{sub 11}DP) to 2.1 ng g{sup −1} ww for TBA in eggs, 0.001 ng g{sup −1} ww for Dechlorane metabolites to 9.4 ng g{sup −1} ww for TBA in gonads and 0.002 ng g{sup −1} ww for Dechlorane metabolites to 54 ng g{sup −1} ww for TBA in muscle tissue. Average egg muscle ratios (EMRs) for compounds detectable in artificially matured eels from both Schlei Fjord and Ems River ranged from 0.01 for Dechlorane 602 (DDC-DBF) to 10.4 for PBEB. Strong correlations were found between flame retardant concentrations and lipid content in the analysed tissue types, as well as transfer rates and octanol–water partitioning coefficient, indicating that these parameters were the driving factors for the observed maternal transfer. Furthermore, indications were found, that TBP-DBPE, TBP-AE, BATE and TBA have a significant uptake from the surrounding water, rather than just food and might additionally be formed by metabolism or

  7. Maternal transfer of emerging brominated and chlorinated flame retardants in European eels

    International Nuclear Information System (INIS)

    Sühring, Roxana; Freese, Marko; Schneider, Mandy; Schubert, Sophia; Pohlmann, Jan-Dag; Alaee, Mehran; Wolschke, Hendrik; Hanel, Reinhold; Ebinghaus, Ralf; Marohn, Lasse

    2015-01-01

    The European eel (Anguilla anguilla) is regarded as a critically endangered species. Scientists are in agreement that the “quality of spawners” is a vital factor for the survival of the species. This quality can be impaired by parasites, disease and pollution. Especially endocrine disrupting organic chemicals pose a potential threat to reproduction and development of offspring. To our knowledge, the findings in this publication for the first time describe maternal transfer of contaminants in eels. We analysed the concentrations of in total 53 polybrominated diphenyl ethers (PBDEs) and their halogenated substitutes in muscle, gonads and eggs of artificially matured European eels and in muscle and gonads of untreated European eels that were used for comparison. We found evidence that persistent organic pollutants such as PBDEs, as well as their brominated and chlorinated substitutes are redistributed from muscle tissue to gonads and eggs. Concentrations ranged from 0.001 ng g −1 ww for sum Dechlorane metabolites (DPMA, aCL 10 DP, aCl 11 DP) to 2.1 ng g −1 ww for TBA in eggs, 0.001 ng g −1 ww for Dechlorane metabolites to 9.4 ng g −1 ww for TBA in gonads and 0.002 ng g −1 ww for Dechlorane metabolites to 54 ng g −1 ww for TBA in muscle tissue. Average egg muscle ratios (EMRs) for compounds detectable in artificially matured eels from both Schlei Fjord and Ems River ranged from 0.01 for Dechlorane 602 (DDC-DBF) to 10.4 for PBEB. Strong correlations were found between flame retardant concentrations and lipid content in the analysed tissue types, as well as transfer rates and octanol–water partitioning coefficient, indicating that these parameters were the driving factors for the observed maternal transfer. Furthermore, indications were found, that TBP-DBPE, TBP-AE, BATE and TBA have a significant uptake from the surrounding water, rather than just food and might additionally be formed by metabolism or biotransformation processes. Dechloranes seem to be

  8. Emissions and fate of brominated flame retardants in the indoor environment: A critical review of modelling approaches

    Energy Technology Data Exchange (ETDEWEB)

    Liagkouridis, Ioannis, E-mail: ioannis.liagkouridis@ivl.se [IVL Swedish Environmental Research Institute, P.O. Box 21060, SE 100 31 Stockholm (Sweden); ITM Department of Applied Environmental Science, Stockholm University, SE 106 91 Stockholm (Sweden); Cousins, Ian T. [ITM Department of Applied Environmental Science, Stockholm University, SE 106 91 Stockholm (Sweden); Cousins, Anna Palm [IVL Swedish Environmental Research Institute, P.O. Box 21060, SE 100 31 Stockholm (Sweden)

    2014-09-01

    This review explores the existing understanding and the available approaches to estimating the emissions and fate of semi-volatile organic compounds (SVOCs) and in particular focuses on the brominated flame retardants (BFRs). Volatilisation, an important emission mechanism for the more volatile compounds can be well described using current emission models. More research is needed, however, to better characterise alternative release mechanisms such as direct material–particle partitioning and material abrasion. These two particle-mediated emissions are likely to result in an increased chemical release from the source than can be accounted for by volatilisation, especially for low volatile compounds, and emission models need to be updated in order to account for these. Air–surface partitioning is an important fate process for SVOCs such as BFRs however it is still not well characterised indoors. In addition, the assumption of an instantaneous air–particle equilibrium adopted by current indoor fate models might not be valid for high-molecular weight, strongly sorbing compounds. A better description of indoor particle dynamics is required to assess the effect of particle-associated transport as this will control the fate of low volatile BFRs. We suggest further research steps that will improve modelling precision and increase our understanding of the factors that govern the indoor fate of a wide range of SVOCs. It is also considered that the appropriateness of the selected model for a given study relies on the individual characteristics of the study environment and scope of the study. - Highlights: • Current emission models likely underestimate the release of low volatile BFRs from products. • Material abrasion and direct material–dust partitioning are important, yet understudied emission mechanisms. • Indoor surfaces can be significant sinks, but the mechanism is poorly understood. • Indoor fate of low volatile BFRs is strongly associated with particle

  9. Brominated flame retardant emissions from the open burning of five plastic wastes and implications for environmental exposure in China.

    Science.gov (United States)

    Ni, Hong-Gang; Lu, Shao-You; Mo, Ting; Zeng, Hui

    2016-07-01

    Based on the most widely used plastics in China, five plastic wastes were selected for investigation of brominated flame retardant (BFR) emission behaviors during open burning. Considerable variations were observed in the emission factors (EF) of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) from the combustion of different plastic wastes. Distribution of BFR output mass showed that ΣPBDE was emitted mainly by the airborne particle (51%), followed by residual ash (44%) and the gas phase (5.1%); these values for ΣHBCD were 62%, 24%, and 14%, respectively. A lack of mass balance after the burning of the plastic wastes for some congeners (output/input mass ratios>1) suggested that formation and survival exceeded PBDE decomposition during the burns. However, that was not the case for HBCD. A comparison with literature data showed that the open burning of plastic waste is major source of PBDE compared to regulated combustion activities. Even for state-of-the-art waste incinerators equipped with sophisticated complex air pollution control technologies, BFRs are released on a small scale to the environment. According to our estimate, ΣPBDE release to the air and land from municipal solid waste (MSW) incineration plants in China in 2015 were 105 kg/year and 7124 kg/year. These data for ΣHBCD were 25.5 and 71.7 kg/year, respectively. Considering the fact that a growing number of cities in China are switching to incineration as the preferred method for MSW treatment, our estimate is especially important. This study provides the first data on the environmental exposure of BFRs emitted from MSW incineration in China. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Analysis of brominated and phosphate-based flame retardants in polymer samples by HPLC-UV/MS and online-GPC-HPLC-UV

    Energy Technology Data Exchange (ETDEWEB)

    Schlummer, M.; Brandl, F. [Fraunhofer-Institut fuer Verfahrenstechnik und Verpackung (IVV), Freising (Germany); Maeurer, A.

    2004-09-15

    Here we present two analytical approaches for the identification and quantification of brominated and phosphate-based flame retardants. The first is an HPLC-UV/MS approach, which allows the separation and unequivocal identification and quantification of at least 15 different technical flame retardants. The second approach was set-up as a screening tool, consisting of a GPC separation coupled to an HPLC-UV device.

  11. Exposure to brominated flame retardants, perfluorinated compounds, phthalates and phenols in European birth cohorts: ENRIECO evaluation, first human biomonitoring results, and recommendations

    NARCIS (Netherlands)

    Casas, M.; Chevrier, C.; Hond, E.D.; Fernandez, M.F.; Pierik, F.; Philippat, C.; Slama, R.; Toft, G.; Vandentorren, S.; Wilhelm, M.; Vrijheid, M.

    2013-01-01

    There are emerging concerns about potential effects on child health and development of early-life exposure to substances such as brominated flame retardants (BFRs), perfluorinated compounds (PFCs), phthalates and phenols (including bisphenol A (BPA)); pregnancy and birth cohort studies are ideally

  12. Body burdens of brominated flame retardants and other persistent organo-halogenated compounds and their descriptors in US girls

    Energy Technology Data Exchange (ETDEWEB)

    Windham, Gayle C., E-mail: gayle.windham@cdph.ca.gov [CA Department of Public Health, DEODC, 850 Marina Bay Pkwy, Bldg. P, Richmond, CA 94804 (United States); Pinney, Susan M. [University of Cincinnati College of Medicine, Cincinnati, OH 45267 (United States); Sjodin, Andreas [Centers for Disease Control and Prevention, Atlanta, GA 30341 (United States); Lum, Raymond [Impact Assessment Inc., San Diego, CA (United States); Jones, Richard S.; Needham, Larry L. [Centers for Disease Control and Prevention, Atlanta, GA 30341 (United States); Biro, Frank M. [University of Cincinnati College of Medicine, Cincinnati, OH 45267 (United States); Hiatt, Robert A. [University of California Medical School, San Francisco, CA (United States); Kushi, Lawrence H. [Kaiser Permanente Northern California, Oakland, CA 94612 (United States)

    2010-04-15

    Background: Levels of brominated flame retardants are increasing in US populations, yet little data are available on body burdens of these and other persistent hormonally active agents (HAAs) in school-aged children. Exposures to such chemicals may affect a number of health outcomes related to development and reproductive function. Objective: Determine the distribution of biomarkers of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organo-chlorinated pesticides (OCPs), such as DDT/DDE, in children, and their variation by key descriptor variables. Methods: Ethnically diverse cohorts of girls 6-8 y old at baseline are being followed for growth and pubertal development in a multi-site, longitudinal study. Nearly 600 serum samples from the California and Ohio sites were analyzed for lipids, 35 PCB congeners, 11 PBDE congeners, and 9 OCPs. The biomarker distributions were examined and geometric means compared for selected analytes across categories of age, race, site, body mass index (BMI), parental education, maternal age at delivery, and breast feeding in adjusted models. Results: Six PBDE congeners were detected among greater than 70% of samples, with BDE-47 having the highest concentration (median 42.2, range 4.9-855 ng/g lipid). Girls in California had adjusted geometric mean (GM) PBDE levels significantly higher than girls in Ohio. Furthermore, Blacks had significantly higher adjusted GMs of all six PBDE congeners than Whites, and Hispanics had intermediate values. GMs tended to be lower among more obese girls, while other variables were not strongly associated. In contrast, GMs of the six PCB congeners most frequently detected were significantly lower among Blacks and Hispanics than Whites. PCBs and the three pesticides most frequently detected were also consistently lower among girls with high BMI, who were not breast-fed, whose mothers were younger, or whose care-givers (usually parents) were less educated. Girls in California had

  13. Body burdens of brominated flame retardants and other persistent organo-halogenated compounds and their descriptors in US girls

    International Nuclear Information System (INIS)

    Windham, Gayle C.; Pinney, Susan M.; Sjodin, Andreas; Lum, Raymond; Jones, Richard S.; Needham, Larry L.; Biro, Frank M.; Hiatt, Robert A.; Kushi, Lawrence H.

    2010-01-01

    Background: Levels of brominated flame retardants are increasing in US populations, yet little data are available on body burdens of these and other persistent hormonally active agents (HAAs) in school-aged children. Exposures to such chemicals may affect a number of health outcomes related to development and reproductive function. Objective: Determine the distribution of biomarkers of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organo-chlorinated pesticides (OCPs), such as DDT/DDE, in children, and their variation by key descriptor variables. Methods: Ethnically diverse cohorts of girls 6-8 y old at baseline are being followed for growth and pubertal development in a multi-site, longitudinal study. Nearly 600 serum samples from the California and Ohio sites were analyzed for lipids, 35 PCB congeners, 11 PBDE congeners, and 9 OCPs. The biomarker distributions were examined and geometric means compared for selected analytes across categories of age, race, site, body mass index (BMI), parental education, maternal age at delivery, and breast feeding in adjusted models. Results: Six PBDE congeners were detected among greater than 70% of samples, with BDE-47 having the highest concentration (median 42.2, range 4.9-855 ng/g lipid). Girls in California had adjusted geometric mean (GM) PBDE levels significantly higher than girls in Ohio. Furthermore, Blacks had significantly higher adjusted GMs of all six PBDE congeners than Whites, and Hispanics had intermediate values. GMs tended to be lower among more obese girls, while other variables were not strongly associated. In contrast, GMs of the six PCB congeners most frequently detected were significantly lower among Blacks and Hispanics than Whites. PCBs and the three pesticides most frequently detected were also consistently lower among girls with high BMI, who were not breast-fed, whose mothers were younger, or whose care-givers (usually parents) were less educated. Girls in California had

  14. Legacy and novel brominated flame retardants in interior car dust – Implications for human exposure

    International Nuclear Information System (INIS)

    Besis, Athanasios; Christia, Christina; Poma, Giulia; Covaci, Adrian; Samara, Constantini

    2017-01-01

    Brominated flame retardants (BFRs) are organobromine compounds with an inhibitory effect on combustion chemistry tending to reduce the flammability of products. Concerns about health effects and environmental threats have led to phase-out or restrictions in the use of Penta-, Octa- and Deca-BDE technical formulations, increasing the demand for Novel BFRs (NBFRs) as replacements for the banned formulations. This study examined the occurrence of legacy and NBFRs in the dust from the interior of private cars in Thessaloniki, Greece, aged from 1 to 19 years with variable origin and characteristics. The determinants included 20 Polybrominated Diphenyl Ethers (PBDEs) (Di-to Deca-BDEs), four NBFRs such as Decabromodiphenylethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB), and bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH), three isomers of hexabromocyclododecane (HBCD), and tetrabromobisphenol A (TBBPA). The concentrations of ∑ 20 PBDE ranged from 132 to 54,666 ng g −1 being dominated by BDE-209. The concentrations of ∑ 4 NBFRs ranged from 48 to 7626 ng g −1 and were dominated by DBDPE, the major substitute of BDE-209. HBCDs ranged between <5 and 1745 ng g −1 , with alpha-HBCD being the most prevalent isomer Finally, the concentrations of TBBPA varied from <10 to 1064 ng g −1 . The concentration levels and composition profiles of BFRs were investigated in relation to the characteristics of cars, such as year of manufacture, country of origin, and interior equipment (type of car seats, electronic and electrical components, ventilation, etc.). The average daily intakes of selected BFRs (BDE-47, BDE-99, BDE-153, BDE-209, TBB, BTBPE, TBPH, DBDPE, HBCDs and TBBPA) via ingestion and dermal absorption were estimated for adults and toddlers. The potential health risk due to BFRs was found to be several orders of magnitude lower than their corresponding reference dose (RfD) values. - Highlights:

  15. Brominated flame retardant emissions from the open burning of five plastic wastes and implications for environmental exposure in China

    International Nuclear Information System (INIS)

    Ni, Hong-Gang; Lu, Shao-You; Mo, Ting; Zeng, Hui

    2016-01-01

    Based on the most widely used plastics in China, five plastic wastes were selected for investigation of brominated flame retardant (BFR) emission behaviors during open burning. Considerable variations were observed in the emission factors (EF) of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) from the combustion of different plastic wastes. Distribution of BFR output mass showed that ΣPBDE was emitted mainly by the airborne particle (51%), followed by residual ash (44%) and the gas phase (5.1%); these values for ΣHBCD were 62%, 24%, and 14%, respectively. A lack of mass balance after the burning of the plastic wastes for some congeners (output/input mass ratios > 1) suggested that formation and survival exceeded PBDE decomposition during the burns. However, that was not the case for HBCD. A comparison with literature data showed that the open burning of plastic waste is major source of PBDE compared to regulated combustion activities. Even for state-of-the-art waste incinerators equipped with sophisticated complex air pollution control technologies, BFRs are released on a small scale to the environment. According to our estimate, ΣPBDE release to the air and land from municipal solid waste (MSW) incineration plants in China in 2015 were 105 kg/year and 7124 kg/year. These data for ΣHBCD were 25.5 and 71.7 kg/year, respectively. Considering the fact that a growing number of cities in China are switching to incineration as the preferred method for MSW treatment, our estimate is especially important. This study provides the first data on the environmental exposure of BFRs emitted from MSW incineration in China. - Highlights: • Airborne particle and residue ash are two major emissions from burns of plastic waste. • Mass unbalance showed formation of PBDE occurred during burning process. • Open burning of plastic waste is major source of PBDE compared to industrial sources. • BFRs in residual ash of waste combustion would be

  16. Characterization of PBDEs and novel brominated flame retardants in seawater near a coastal mariculture area of the Bohai Sea, China.

    Science.gov (United States)

    Wang, Yan; Wu, Xiaowei; Zhao, Hongxia; Xie, Qing; Hou, Minmin; Zhang, Qiaonan; Du, Juan; Chen, Jingwen

    2017-02-15

    The concentrations and distributions of PBDEs and novel brominated flame retardants (NBFRs) in dissolved phase of surface seawater near a coastal mariculture area of the Bohai Sea were investigated. The total concentrations of PBDE and NBFRs were in the range of 15.4-65.5 and 2.12-13.6ng/L, respectively. The highest concentration was discovered in the water near an anchorage ground, whereas concentrations in water samples from offshore cage-culture area were not elevated. Relatively high concentrations of BDE28, 99, and 100 were discovered in the medium range of distance from shore, where is the path of tidal or coastal current. This suggested that inputs from ships or through tidal current rather than mariculture activities may be the main sources of BFRs in this area. BDE209, BDE47, hexabromobenzene (HBB), and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB) were the most abundant BFR congeners. Relatively high proportions of these BFRs may originate from discharge of wastewater nearby or degradation from higher brominated PBDEs. No correlations were found between BFR concentrations and water dissolved organic carbon, suggesting that concentrations and distributions of BFRs in this area were source-dependent. The relatively high concentrations in this study emphasized the importance of monitoring and managing BFR contaminations in mariculture areas of China. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. In vitro effects of brominated flame retardants and metabolites on CYP17 catalytic activity: A novel mechanism of action?

    International Nuclear Information System (INIS)

    Canton, Rocio F.; Sanderson, J. Thomas; Nijmeijer, Sandra; Bergman, Ake; Letcher, Robert J.; Berg, Martin van den

    2006-01-01

    Fire incidents have decreased significantly over the last 20 years due, in part, to regulations requiring addition of flame retardants (FRs) to consumer products. Five major classes of brominated flame retardants (BFRs) are hexabromocyclododecane isomers (HBCDs), tetrabromobisphenol-A (TBBPA) and three commercial mixtures of penta-, octa- and deca-polybrominated diphenyl ether (PBDE) congeners, which are used extensively as commercial FR additives. Furthermore, concentrations of PBDEs have been rapidly increasing during the 1999s in human breast milk and a number of endocrine effects have been reported. We used the H295R human adrenocortical carcinoma cell line to assess possible effects of some of these BFRs (PBDEs and several of their hydroxylated (OH) and methoxylated (CH 3 O) metabolites or analogues), TBBPA and brominated phenols (BPs) on the combined 17α-hydroxylase and 17,20-lyase activities of CYP17. CYP17 enzyme catalyzes an important step in sex steroidogenesis and is responsible for the biosynthesis of dehydroepiandrosterone (DHEA) and androstenedione in the adrenals. In order to study possible interactions with BFRs, a novel enzymatic method was developed. The precursor substrate of CYP17, pregnenolone, was added to control and exposed H295R cells, and enzymatic production of DHEA was measured using a radioimmunoassay. In order to avoid pregnenolone metabolism via different pathways, specific chemical inhibitor compounds were used. None of the parent/precursor BFRs had a significant effect (P 3 O group eliminated this cytotoxic effect, but CYP17 activity measured as DHEA production was still significantly inhibited. Other OH- or CH 3 O-PBDE analogues were used to elucidate possible structural properties behind this CYP17 inhibition and associated cytotoxicity, but no distinct structure activity relationship could be determined. These in vitro results indicate that OH and CH 3 O-PBDEs have potential to interfere with CYP17 activity for which the in vivo

  18. Levels of brominated flame retardants and other pesistent organic pollutants in breast milk samples from Limpopo province, South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Darnerud, Per Ola, E-mail: poda@slv.se [Toxicology Division, National Food Administration, P.O. Box 622, SE-751 26 Uppsala (Sweden); Aune, Marie; Larsson, Lotta [Chemistry Division 2, National Food Administration, P.O. Box 622, SE-751 26 Uppsala (Sweden); Lignell, Sanna [Toxicology Division, National Food Administration, P.O. Box 622, SE-751 26 Uppsala (Sweden); Mutshatshi, Tshinanne; Okonkwo, Jonathan; Botha, Ben [Faculty of Science, Tshwane University of Technology, Pretoria (South Africa); Agyei, Nana [Department of Chemistry, Limpopo University, Medunsa (South Africa)

    2011-09-01

    The non-occupational exposure to brominated flame retardants, and other persistent organic pollutants (POPs) was studied by collecting human breast milk samples from mothers residing in Thohoyandou area, a rural district in the Limpopo Province, northern part of South Africa (SA). Of all collected samples to be analysed (n = 28), those with large enough milk volumes, (n = 14) were quantified for polybrominated diphenyl ethers (PBDEs) (9 congeners: BDE-28, 47, 66, 99, 100, 138, 153, 154, and 183) and hexabromocyclododecane (HBCD) on a GC equipped with dual capillary columns and dual electron-capture detectors (ECD). The levels of PBDE congeners (median sumBDE 1.3 ng/g of lipids) and of HBCD were not far from levels generally found in European studies, and this study may be the first report on the presence of PBDEs and HBCD in SA breast milk. On a congener basis, the finding of comparably high BDE-183 levels suggests a specific PBDE usage, or contamination situation in SA. Apart from BFRs, the high DDT levels found in the breast milk from this area (median and maximum sumDDT levels of about 4 600 and over 20 000 ng/g of lipids, respectively; n = 28) have earlier been reported. In addition, other POPs (PCBs, HCB and HCHs) were found in SA breast milk, at relatively low levels. To conclude, measurable levels of PBDEs and HBCD, and a specific BDE congener pattern, were found in breast milk from the Limpopo province, SA. A number of other POPs, including DDTs in high levels, were also present. - Highlights: {yields} Persistent organic pollutants (POPs) were analysed in South African breast milk. {yields} Focus of interest were brominated flame retardants (BRFs). {yields} Sampling area was the rural Limpopo Province, northern SA. {yields} Probably the first reported African data on BFRs (PBDEs, HBCD) in breast milk. {yields} Reported BFR data similar to European levels.

  19. Brominated flame retardants and organochlorine pollutants in eggs of little owls (Athene noctua) from Belgium

    International Nuclear Information System (INIS)

    Jaspers, Veerle; Covaci, Adrian; Maervoet, Johan; Dauwe, Tom; Voorspoels, Stefan; Schepens, Paul; Eens, Marcel

    2005-01-01

    Residues of brominated diphenylethers (PBDEs), organochlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) were measured in 40 eggs of little owls (Athene noctua), a terrestrial top predator from Belgium. The major organohalogens detected were PCBs (median 2,600 ng/g lipid, range 790-23000 ng/g lipid). PCB 153,138/163, 170, 180 and 187 were the predominant congeners and constituted 71% of total sum PCBs. PBDEs were measurable in all samples, but their concentrations were much lower than for PCBs, with a range from 29-572 ng/g lipid (median 108 ng/g lipid). The most prevalent PBDE congeners in little owl egg samples were BDE 47, 99 and 153. This profile differs from the profile in marine bird species, for which BDE 47 was the dominant congener, indicating that terrestrial birds may be more exposed to higher brominated BDE congeners than marine birds. The fully brominated BDE 209 could be detected in one egg sample (17 ng/g lipid), suggesting that higher brominated BDEs may accumulate in terrestrial food chains. Brominated biphenyl (BB) 153 was determined in all egg samples, with levels ranging from 0.6 to 5.6 ng/g lipid (median 1.3 ng/g lipid). Additionally, hexabromocyclododecane (HBCD) could be identified and quantified in only two eggs at levels of 20 and 50 ng/g lipid. OCPs were present at low concentrations, suggesting a rather low contamination of the sampled environment with OCPs (median concentrations of sum DDTs: 826 ng/g lipid, sum chlordanes: 1,016 ng/g lipid, sum HCHs: 273 ng/g lipid). Hexachlorobenzene (HCB) and octachlorostyrene (OCS) were also found at low median levels of 134 and 3.4 ng/g lipid, respectively. Concentrations of most analytes were significantly higher in eggs collected from deserted nests in comparison to addled (unhatched) eggs, while eggshell thickness did not differ between deserted and addled eggs. No significant correlations were found between eggshell thickness and the analysed organohalogens. - PBDEs are measurable

  20. Dynamics of brominated flame retardants removal in contaminated wastewater sewage sludge under anaerobic conditions.

    Science.gov (United States)

    Stiborova, Hana; Vrkoslavova, Jana; Pulkrabova, Jana; Poustka, Jan; Hajslova, Jana; Demnerova, Katerina

    2015-11-15

    Disposal of solid waste to landfills from waste water sewage treatment plants (WWTPs) serves as a potential source of contamination by polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD). Native microbial communities have been found to degrade a variety of xenobiotics, such as PBDEs and HBCDs. This study investigates the potential of autochthonous microflora to remove 11 PBDE congeners and HBCDs in waste water sludge under anaerobic conditions. Laboratory microcosms were constructed with sewage sludge from the WWTPs of Hradec Kralove and Brno. BDE 209 was detected as the prevailing congener in concentrations 685 and 1403 ng/g dw and the total amounts of 10 lower PBDEs (BDE 28, 47, 49, 66, 85, 99, 100, 153, 154, 183) were 605 and 205 ng/g dw in sludge from Hradec Kralove and Brno, respectively. The levels of HBCD were detected in both sludge lower than 24 ng/g dw. The experiment was carried out for 15 months. After three months of incubation, HBCD was completely degraded to below detection limits. In sewage from both WWTPs, the higher brominated DEs were removed faster than the lower brominated congeners. One exception was tri-BDE, which was degraded completely within 15 months of cultivation. A significant increase in congener tetra-BDE 49 concentrations was observed over the course of the experiment in all tested sewage. The relative distribution of individual congeners among all PBDEs changed after 15 months of the incubation in favour of lower brominated congeners. This indicates that debromination is the major mechanism of anaerobic biodegradation. Despite of the increase of BDE 49, the overall removal of all 11 PBDEs achieved the levels of 47.4 and 68.7% in samples from WWTPs Hradec Kralove and Brno, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Brominated flame retardants in aquatic organisms from the North Sea in comparison with biota from the high Arctic marine environment.

    Science.gov (United States)

    Sørmo, Eugen G; Jenssen, Bjørn M; Lie, Elisabeth; Skaare, Janneche U

    2009-10-01

    The extent of trophic transfer of brominated flame retardants (BFRs), including hexabromocyclododecane (HBCD) and seven polybrominated diphenyl ethers (PBDEs), were examined in pelagic and benthic aquatic animals (invertebrates and fish) in a near-shore estuary environment of the southeastern North Sea (Norway; 59 degrees N). Whole-body burdens of HBCD and several of the most abundant PBDEs biomagnified with increasing trophic position in the food web. Biomagnification of HBCD was particularly strong, resulting in whole-body burdens of this compound comparable to those of total PBDEs in the higher-trophic-level species. Body burdens of PBDEs were higher in pelagic than in benthic aquatic organisms. This was particularly evident for the lesser-brominated and volatile PBDE congeners. Atmospheric gas-water-phytoplankton exchange of these volatile compounds over the water surface may account for this observation. The PBDE burdens in pelagic zooplankton from the North Sea were more than 60-fold greater than those in corresponding pelagic zooplankton from the colder high Arctic latitudes (>78 degrees N) of Norway (Svalbard). This great difference may relate to reduced chemical gas-water exchange over open waters at the colder Arctic latitudes. However, previously measured whole-body burdens of BFRs in other aquatic marine organisms from the high Arctic were comparable or even exceeded those in the North Sea samples of the present study. These include sympagic (sea ice-associated) invertebrates and fish accumulating high burdens of particle-associated BFRs. The present study provides new insight regarding the distribution of BFRs in ecologically different compartments of marine ecosystems, essential information for understanding the food-web transfer and geographical dispersal of these compounds.

  2. Bromine and water quality – Selected aspects and future perspectives

    International Nuclear Information System (INIS)

    Winid, Bogumiła

    2015-01-01

    Bromine is a microelement present in waters, both in inorganic and in a wide range of organic compounds, though at lower concentrations. Typically, concentrations of organobromine compounds in waters are several orders of magnitude lower than of bromides. Two issues are addressed in the paper: the influence of bromides on the quality of treated waters and organobromines as contaminants of natural waters. Bromide presence in treated water gives rise to formation of potentially mutagenic disinfection by-products (DBPs). Registered amounts of DBPs in potable waters, exceeding the admissible levels, and the published data on DBPs in waters used for leisure and recreation activities, clearly indicate the health risk. Major sources are identified and registered concentrations of EDB, DBCB, methyl bromide, bromacil and PBDEs in the aquatic environment are summarized. The effects of bromide on DBPs formation and numerous examples of organobromine contamination of the aquatic environment indicate that the presence of bromides and organobromine compounds in the aquatic environment will have to be given more consideration, for several reasons. Firstly, larger amounts of bromide are present in saline and contaminated waters and the proportion of such waters being handled is increasing. Similarly, the processes of water purification, treatment and disinfection are now playing a major role. Secondly, emissions from manufacturing of bromine-containing materials growing, due to, inter alia, intensive development of the electronic industry and the plastic manufacturing sector. Thirdly, bromine compounds are also used as medicine ingredients. There is now a growing awareness of the presence of pharmaceuticals in the aquatic environment. Fourth, low bromide concentrations in hypergene zones may be modified in the future, partly because of the climate changes, which may give rise to difficulties with water treatment systems. Water quality standards having relevance to water used for

  3. Brominated flame retardants, tetrabromobisphenol A and hexabromocyclododecane, activate mitogen-activated protein kinases (MAPKs) in human natural killer cells.

    Science.gov (United States)

    Cato, Anita; Celada, Lindsay; Kibakaya, Esther Caroline; Simmons, Nadia; Whalen, Margaret M

    2014-12-01

    Natural killer (NK) cells provide a vital surveillance against virally infected cells, tumor cells, and antibody-coated cells through the release of cytolytic mediators and gamma interferon (IFN-γ). Hexabromocyclododecane (HBCD) is a brominated flame retardant used primarily in expanded (EPS) and extruded (XPS) polystyrene foams for thermal insulation in the building and construction industry. Tetrabromobisphenol A (TBBPA) is used both as a reactive and an additive flame retardant in a variety of materials. HBCD and TBBPA contaminate the environment and are found in human blood samples. In previous studies, we have shown that other environmental contaminants, such as the dibutyltin (DBT) and tributyltin (TBT), decrease NK lytic function by activating mitogen-activated protein kinases (MAPKs) in the NK cells. HBCD and TBBPA also interfere with NK cell(s) lytic function. The current study evaluates whether HBCD and/or TBBPA have the capacity to activate MAPKs and MAPK kinases (MAP2Ks). The effects of concentrations of HBCD and TBBPA that inhibited lytic function on the phosphorylation state and total levels of the MAPKs (p44/42, p38, and JNK) and the phosphorylation and total levels of the MAP2Ks (MEK1/2 and MKK3/6) were examined. Results indicate that exposure of human NK cells to 10-0.5 μM HBCD or TBBPA activate MAPKs and MAP2Ks. This HBCD and TBBPA-induced activation of MAPKs may leave them unavailable for activation by virally infected or tumor target cells and thus contributes to the observed decreases in lytic function seen in NK cells exposed to HBCD and TBBPA.

  4. Effects of the brominated flame retardants hexabromocyclododecane (HBCDD), and tetrabromobisphenol A (TBBPA), on hepatic enzymes and other biomarkers in juvenile rainbow trout and feral eelpout

    International Nuclear Information System (INIS)

    Ronisz, D.; Farmen Finne, E.; Karlsson, H.; Foerlin, L.

    2004-01-01

    Brominated flame retardants (BFRs) leak out in the environment, including the aquatic one. Despite this, sublethal effects of these chemicals are poorly investigated in fish. In this study, a screening of selected biomarkers in juvenile rainbow trout (Oncorhynchus mykiss) and feral eelpout (Zoarces viviparus) was performed after exposure to hexabromocyclododecane (HBCDD) and tetrabromobisphenol A (TBBPA). Rainbow trout was injected intraperitoneally (i.p.) with HBCDD or TBBPA. Two out of four short-term experiments with HBCDD showed an increase in the activity of catalase. A 40% increase in liver somatic index (LSI) could be observed after 28 days. HBCDD did also seem to have an inhibitory effect on CYP1A's activity (ethoxyresorufin-O-deethylase (EROD)). A putative peroxisome proliferating activity of the compound was investigated without giving a definite answer. HBCDD did not seem to be estrogenic or genotoxic. TBBPA increased the activity of glutathione reductase (GR) after 4, 14 and 28 days in rainbow trout suggesting a possible role of this compound in inducing oxidative stress. The compound did not seem to be estrogenic. TBBPA seemed to compete with the artificial substrate ethoxyresorufin in vitro, during the EROD assay. In eelpout, only one 5 days in vivo experiment was performed. Neither of the compounds gave rise to any effect in this fish. This was the first screening of sublethal effects of the two chemicals in fish, using high doses. Our results indicate that there is a need for further studies of long-term, low-dose effects of these two widely used flame retardants

  5. Polybrominated diphenyl ethers and “novel” brominated flame retardants in floor and elevated surface house dust from Iraq: Implications for human exposure assessment

    Directory of Open Access Journals (Sweden)

    Layla Salih Al-Omran

    2016-03-01

    Full Text Available Concentrations of polybrominated diphenyl ethers (PBDEs and selected novel brominated flame retardants (NBFRs were measured in indoor dust from the living areas of 18 homes in Basrah, Iraq. This is the first report of contamination of the Iraqi environment with these chemicals. To evaluate the implications for human exposure, samples were collected from both the floor and from elevated surfaces like tables, shelves and chairs. When normalised for the organic carbon content of the dust sample, concentrations in elevated surface dust of BDE-99, BDE-209, pentabromoethylbenzene (PBEB, bis (2-ethylhexyl 3,4,5,6-tetrabromophthalate (BEH-TEBP, and decabromodiphenylethane (DBDPE exceeded significantly (p < 0.05 those in floor dust from the same rooms. This suggests that previous studies that base estimates of adult exposure via dust ingestion on floor dust, may underestimate exposure. Such underestimation is less likely for toddlers who are far more likely to ingest floor dust. Concentrations of PBDEs and NBFRs in indoor dust from Basrah, Iraq are at the lower end of levels reported elsewhere. The PBDE contamination pattern in our samples suggests that use in Iraq of the Deca-BDE formulation, exceeds substantially that of Penta-BDE, but that use of the Octa-BDE formulation has been higher in Iraq than in some other regions. Reassuringly, our estimates of exposure to our target BFRs via dust ingestion for the Iraqi population fall well below the relevant health-based limit values.

  6. Emissions of brominated flame retardants in Asia: consideration of its potential risk form the view point of the Norwegian regulation

    Science.gov (United States)

    Kikuchi, Ryunosuke; Gerardo, Romeu; Gorbacheva, Tamara

    2010-05-01

    Flame retardants can be divided into two broad categories: additive or reactive, which can be further more divided into brominated or non-brominated sub-categories. These retardants are found in many commercial products such as computers, television sets, furniture, carpets, etc. They are of environmental concern due to their persistence, potential for bioaccumulation and widespread distribution via atmospheric transport, and possible adverse effects in wildlife and humans. Tetrabromobisphenol-A (TBBPA) is mainly used in electrical and electronic appliances (circuit board in particular), and the application of TBBPA accounts for about two thirds of the global production of brominated flame retardant (BFR). The European Union Risk Assessment does not support the restriction of TBBPA: i.e. no risk is identified for the reactive use of TBBPA such as in epoxy resin used in circuit boards. By contrast, in 2007 Norway notified the World Trade Organization of its intention to prohibit 18 substances from consumer goods (Notification No. 2007/9016/N), called the Prohibition on Certain Hazardous Substances in Consumer Products (PoHS). TBBPA is listed in this prohibition list. Marine conservation is recognized as a key issue in Norwegian fishery management e.g. wastewater management in the framework of the North Sea Declarations. TBBPA is very water-soluble, and dimethyl-TBBPA is lipophilic and may accumulate in fat. TBBPA is not readily biodegradable and can have long-term effects in the aquatic environment. Norwegian examples are summarized: TBBPA was found in marine sediment samples from Tromsø harbor (northern Norway) and in Atlantic cod from Lofoten and Varanger; TBBPA has been detected in Norwegian peregrine falcon and golden eagle eggs; and TBBPA has been detected in the blood in the general population of Norway. From these viewpoints, it can be considered that Norway needs to strictly control TBBPA emissions. In recent times, Asia has emerged as one of the leading

  7. Brominated flame retardants in mangrove sediments of the Pearl River Estuary, South China: spatial distribution, temporal trend and mass inventory.

    Science.gov (United States)

    Zhang, Zai-Wang; Sun, Yu-Xin; Sun, Kai-Feng; Xu, Xiang-Rong; Yu, Shen; Zheng, Tian-Ling; Luo, Xiao-Jun; Tian, Yun; Hu, Yong-Xia; Diao, Zeng-Hui; Mai, Bi-Xian

    2015-03-01

    Sediments were collected from three mangrove wetlands in the Pearl River Estuary (PRE) of South China to investigate spatial and temporal distributions of polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE). Concentrations of ΣPBDEs, DBDPE and BTBPE in mangrove sediments of the PRE ranged from 1.25-206, 0.364-34.9, and not detected-0.794 ng g(-1) dry weight, respectively. The highest concentrations of ΣPBDEs, DBDPE and BTBPE were found at the mangrove wetland from Shenzhen, followed by Zhuhai and Guangzhou, showing the dependence on the proximity to urban areas. PBDEs were the predominant brominated flame retardants (BFRs) in mangrove sediments. The concentrations of ΣPBDEs, DBDPE and BTBPE in sediment cores showed an increasing trend from the bottom to top layers, reflecting the increasing usage of these BFRs. The inventories of ΣPBDEs, DBDPE and BTBPE in mangrove sediments were 1962, 245, and 4.10 ng cm(-2), respectively. This is the first study to report the occurrence of DBDPE and BTBPE in mangrove ecosystems. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Occurrences and inventories of heavy metals and brominated flame retardants in wastes from printed circuit board production.

    Science.gov (United States)

    Zhou, Xiaoyu; Guo, Jie; Zhang, Wei; Zhou, Peng; Deng, Jingjing; Lin, Kuangfei

    2014-09-01

    Pollutants including heavy metals and brominated flame retardant were detected in 10 types of production wastes from a typical printed circuit board manufacturing plant, and their inventories were estimated. Rinsing water from etching process had the highest concentrations of copper (665.51 mg/L), lead (1.02 mg/L), nickel (3.60 mg/L), chromium (0.97 mg/L), and tin (1.79 mg/L). Powdered solid waste (SW) from the cut lamination process contained the highest tetrabromobisphenol-A (TBBPA) levels (49.86 mg/kg). Polybrominated diphenyl ethers (PBDEs) were absent in this plant, in agreement with the international regulations of PBDE phase out. The pollutant inventories in the wastes exhibited in the order of copper > > zinc > tin ≈ nickel > lead > chromium > > TBBPA. The potential environmental impact of pollutants in SW during production and disposal were further investigated. A high partitioning of pollutant concentration between the total suspended particle and SW (-0.10 < log K TS < 2.12) was observed for most pollutants, indicating the emission pathway from SW to the airborne atmosphere in the workshop. Although SW met the toxicity characteristic leaching procedure, drilling powder with the smallest particle diameter still showed high leachabilities of lead and tin which may lead to a negative environmental impact during disposal.

  9. Characterization of organochlorine pesticides, brominated flame retardants and dioxin-like compounds in shellfish and eel from Fiji.

    Science.gov (United States)

    Lal, Vincent; Bridgen, Phil; Votadroka, Waisea; Raju, Rupantri; Aalbersberg, William

    2014-09-01

    This article gives an overview of a range of persistent organic pollutant chemical levels in shellfish (Batissa violacea and Anadara antiquata) species and eel (Gymnothorax flavimarginatus) from Fiji. As there is limited data in published literature to date, this paper reports first data on a range of persistent organic pollutants and highlights the more prominent POP chemicals present in marine biota in Fiji. A significant number of POP chemicals were detected (e.g. 17 PCDD/PCDF, 12dl-PCBs, organochlorine pesticides and brominated flame retardants), the concentrations found were generally low (e.g. parts per billion level). The low levels of contamination are indicative of a low input from long range and short-range transport as well as few local point sources. Also concentrations of POPs in eel and shellfish from Fiji are low in comparison to wild species in other regions and are within acceptable limits for POP chemicals in fish and fishery products set by the European Union. It describes also results of early studies on basic POPs levels in shellfish in several Pacific Island Countries, which generally show relatively low levels. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Evaluation of 3D-human skin equivalents for assessment of human dermal absorption of some brominated flame retardants.

    Science.gov (United States)

    Abdallah, Mohamed Abou-Elwafa; Pawar, Gopal; Harrad, Stuart

    2015-11-01

    Ethical and technical difficulties inherent to studies in human tissues are impeding assessment of the dermal bioavailability of brominated flame retardants (BFRs). This is further complicated by increasing restrictions on the use of animals in toxicity testing, and the uncertainties associated with extrapolating data from animal studies to humans due to inter-species variations. To overcome these difficulties, we evaluate 3D-human skin equivalents (3D-HSE) as a novel in vitro alternative to human and animal testing for assessment of dermal absorption of BFRs. The percutaneous penetration of hexabromocyclododecanes (HBCD) and tetrabromobisphenol-A (TBBP-A) through two commercially available 3D-HSE models was studied and compared to data obtained for human ex vivo skin according to a standard protocol. No statistically significant differences were observed between the results obtained using 3D-HSE and human ex vivo skin at two exposure levels. The absorbed dose was low (less than 7%) and was significantly correlated with log Kow of the tested BFR. Permeability coefficient values showed increasing dermal resistance to the penetration of γ-HBCD>β-HBCD>α-HBCD>TBBPA. The estimated long lag times (>30 min) suggests that frequent hand washing may reduce human exposure to HBCDs and TBBPA via dermal contact. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Brominated flame retardants and perfluorinated chemicals, two groups of persistent contaminants in Belgian human blood and milk

    Energy Technology Data Exchange (ETDEWEB)

    Roosens, Laurence [Toxicological Centre, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); D' Hollander, Wendy; Bervoets, Lieven [Laboratory for Ecophysiology, Biochemistry and Toxicology, Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Reynders, Hans; Van Campenhout, Karen [Environment and Health Unit, Department of Environment, Nature and Energy, Flemish Government - Koning Albert II-laan 20, Bus 8, 1000 Brussels (Belgium); Cornelis, Christa; Van Den Heuvel, Rosette; Koppen, Gudrun [Unit Environmental Risk and Health, Flemish Institute of Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Covaci, Adrian, E-mail: adrian.covaci@ua.ac.b [Toxicological Centre, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Laboratory for Ecophysiology, Biochemistry and Toxicology, Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium)

    2010-08-15

    We assessed the exposure of the Flemish population to brominated flame retardants (BFRs) and perfluorinated compounds (PFCs) by analysis of pooled cord blood, adolescent and adult serum, and human milk. Levels of polybrominated diphenyl ethers (PBDEs) in blood (range 1.6-6.5 ng/g lipid weight, lw) and milk (range 2.0-6.4 ng/g lw) agreed with European data. Hexabromocyclododecane ranged between <2.1-5.7 ng/g lw in milk. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) dominated in blood and ranged between 1 and 171 ng/mL and <0.9-9.5 ng/mL, respectively. Total PFC levels in milk ranged between <0.5-29 ng/mL. A significant increase in PBDE concentrations was detected from newborns (median 2.1) to the adolescents and adults (medians 3.8 and 4.6 ng/g lw, respectively). An identical trend was observed for PFOS, but not for PFOA. We estimated that newborn exposure to BFRs and PFCs occurs predominantly post-natally, whereas placental transfer has a minor impact on the body burden. - The exposure to BFRs and PFCs of general Flemish population has been assessed throughout several age groups.

  12. Three decades (1983-2010) of contaminant trends in East Greenland polar bears (Ursus maritimus). Part 2: brominated flame retardants.

    Science.gov (United States)

    Dietz, Rune; Rigét, Frank F; Sonne, Christian; Born, Erik W; Bechshøft, Thea; McKinney, Melissa A; Drimmie, Robert J; Muir, Derek C G; Letcher, Robert J

    2013-09-01

    Brominated flame retardants were determined in adipose tissues from 294 polar bears (Ursus maritimus) sampled in East Greenland in 23 of the 28years between 1983 and 2010. Significant linear increases were found for sum polybrominated diphenyl ether (ΣPBDE), BDE100, BDE153, and hexabromocyclododecane (HBCD). Average increases of 5.0% per year (range: 2.9-7.6%/year) were found for the subadult polar bears. BDE47 and BDE99 concentrations did not show a significant linear trend over time, but rather a significant non-linear trend peaking between 2000 and 2004. The average ΣPBDE concentrations increased 2.3 fold from 25.0ng/g lw (95% C.I.: 15.3-34.7ng/g lw) in 1983-1986 to 58.5ng/g lw (95% C.I.: 43.6-73.4ng/g lw) in 2006-2010. Similar but fewer statistically significant trends were found for adult females and adult males likely due to smaller sample size and years. Analyses of δ(15)N and δ(13)C stable isotopes in hair revealed no clear linear temporal trends in trophic level or carbon source, respectively, and non-linear trends differed among sex and age groups. These increasing concentrations of organobromine contaminants contribute to complex organohalogen mixture, already causing health effects to the East Greenland polar bears. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Effects of dietary exposure to brominated flame retardant BDE-47 on thyroid condition, gonadal development and growth of zebrafish

    Science.gov (United States)

    Torres, Leticia; Orazio, Carl E.; Peterman, Paul H.; Patino, Reynaldo

    2013-01-01

    Little is known about the effects of brominated flame retardants in teleosts and some of the information currently available is inconsistent. This study examined effects of dietary exposure to 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) on thyroid condition, body mass and size, and gonadal development of zebrafish. Pubertal, 49-day-old (posthatch) fish were fed diets without BDE-47 (control) or with 1, 5 or 25 μg/g BDE-47/diet. Treatments were conducted in triplicate 30-L tanks each containing 50 zebrafish, and 15 fish per treatment (5 per tank) were sampled at days 40, 80 and 120 of exposure. Measurements were taken of body mass, standard length, head depth and head length. Sex (at 40–120 days of exposure), germ cell stage (at 40 days) and thyroid condition (at 120 days; follicular cell height, colloid depletion, angiogenesis) were histologically determined. Whole-body BDE-47 levels at study completion were within the high end of levels reported in environmentally exposed (wild) fishes. Analysis of variance was used to determine differences among treatments at each sampling time. No effects were observed on thyroid condition or germ cell stage in either sex. Reduced head length was observed in females exposed to BDE-47 at 80 days but not at 40 or 120 days. In males, no apparent effects of BDE-47 were observed at 40 and 80 days, but fish exposed to 25 μg/g had lower body mass at 120 days compared to control fish. These observations suggest that BDE-47 at environmentally relevant whole-body concentrations does not affect thyroid condition or pubertal development of zebrafish but does affect growth during the juvenile-to-adult transition, especially in males.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-09-01

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

  15. Levels and trends of polybrominated diphenylethers and other brominated flame retardants in wildlife.

    Science.gov (United States)

    Law, Robin J; Alaee, Mehran; Allchin, Colin R; Boon, Jan P; Lebeuf, Michel; Lepom, Peter; Stern, Gary A

    2003-09-01

    In this paper, we review the available data for polybrominated diphenylethers (PBDEs) and other flame retardants in wildlife, with the exception of fishes from Europe and North America which are covered in more detail elsewhere. More data are available for PBDEs than for other compounds, and these show that some of these compounds have become widely distributed in the environment, being found in samples from Europe, Australia, Azerbaijan, North America and the Arctic. Most available data relate to birds and their eggs and marine mammals, but the results of two food web studies are also included. The detection of PBDEs in pelagic marine mammals which feed in deep offshore waters, including baleen whales, indicate that these compounds have found their way into deep-water, oceanic food webs as well as the coastal/shallow sea examples described in detail. In the North Sea study, the most marked increase in lipid-normalised concentrations of six BDE congeners occurred during transfer from predatory fish to marine mammals. In the St. Lawrence Estuary study, marked differences in the ratios observed between species suggested that some fish species may be able to metabolise BDE99.A number of time trend studies have also been conducted, notably in guillemot eggs from Sweden (1969-2000), beluga whales from the Canadian Arctic (1982-1997 and 1989-2001) and from the St. Lawrence Estuary (1988-1999), and ringed seals from the Canadian Arctic (1981-2000). In the temperate latitudes, from these and other studies (e.g. in dated sediment cores), PBDE concentrations began to rise earlier than in those from high latitudes, in line with data for production and use. These trends have now slowed in many cases. Declines could be expected in Europe for many congeners following the cessation of manufacture and use of the penta-mix formulation in the EU, though these are not yet apparent in environmental samples. In Arctic biota, however, the rapidly rising concentrations seen currently in

  16. [Comparative study of the level and distribution of polybrominated diphenyl ethers and new brominated flame retardants in the atmosphere of typical urban].

    Science.gov (United States)

    Wu, Hui; Jin, Jun; Wang, Ying; Li, Ming-Yuan; He, Song-Jie; Xu, Meng; Sun, Yi-Ming

    2014-04-01

    Brominated flame retardants (BFRs) are widely used in industrial and commercial products and are frequently detected in various environmental media. It might be potential harm to the environment and the human body. This study reported the levels of 8 kinds of polybrominated diphenyl ethers (PBDEs: BDE-28, -47, -100, -99, -154, -153, -183, -209) and 3 kinds of new brominated flame retardants (NBFRs: PBT, PBEB, HBB) in the atmosphere of Binhai Development Zone, Weifang City, Shandong Province, which was taken as a BFR production source area and of Nanning City, Guangxi Province, which was taken as a contrast area. The results showed that the average concentrations of sigma8 PBDEs in the atmosphere of Weifang and Nanning were 1.4 x 10(5) pg x m(-3) and 323.0 pg x m(-3), respectively, and the average concentrations of sigma3 NBFRs were 4.2 x 10(3) pg x m(-3) and 11.9 pg x m(-3), respectively. Compared with other cities, the concentrations of BFRs in the atmosphere of the production area were at a high level in the globe, and the concentrations of BFRs in Nanning were similar with other cities in China. The distribution characteristics of PBDEs and NBFRs in the atmosphere of the production area were different from those of Nanning, and the correlations between PBEB, PBT, HBB and BDE-209 were different between Weifang and Nanning.

  17. Human exposure to brominated flame retardants through dust in different indoor environments: Identifying the sources of concentration differences in hair from men and women.

    Science.gov (United States)

    Li, Junqi; Dong, Zheng; Wang, Ying; Bao, Junsong; Yan, Yijun; Liu, Anming; Jin, Jun

    2018-08-01

    Brominated flame retardants (BFRs) can accumulate in humans and are associated with adverse health effects. The study was conducted to determine the differences in Polybrominated diphenyl ethers (PBDEs) and alternative brominated flame retardant (Alt-BFR) concentrations between men and women. We analyzed hair samples from 14 male and 20 female university students, paired dust samples from their dormitories (10 for males and 8 for females), and six dust samples from university teaching buildings. The total PBDE concentrations in hair from females were significantly (three times) higher (p = 0.012) than that from males (means 372 and 109 ng/g, respectively). The mean total PBDE concentrations in classroom and dormitory dust were 36100 and 2012 ng/g, respectively. The PBDE patterns were different in the male and female hair samples, as were the patterns in the classroom and dormitory dust. There are no reports concerning human exposure to BFRs through dust that was assessed considering academic and residential environments simultaneously. The differences between BFR exposure for males and females and the differences between BFR concentrations in hair samples from males and females were consistent for 71.4% of the compounds. However, using only dormitory dust in the calculations gave consistent differences only for 28.6% of the compounds, suggesting that the BFR concentration differences in hair were mainly because females spent much more time than males in classrooms. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Estimation of human percutaneous bioavailability for two novel brominated flame retardants, 2-ethylhexyl tetrabromobenzoate (EH-TBB) and bis(2-ethylhexyl) tetrabromophthalate (BEH-TEBP), using the parallelogram approach

    Science.gov (United States)

    2-ethylhexyltetrabromobenzoate (EH-TBB) and bis(2-ethylhexyl)tetrabromophthalate (BEH-TEBP) are novel brominated flame retardants (FRs). BEH-TEBP is used alone as a plasticizer or with EH-TBB in polyurethane foams; both are contaminants in the indoor and outdoor environments. In ...

  19. An automated wavelength selection for flame spectroscopy

    International Nuclear Information System (INIS)

    Hurteau, M.; Mislan, J.P.; Ashley, R.W.

    1976-01-01

    A simple electro-mechanical programming system is described for use with a flame spectrophotometer. Its application for automated sequential multi-element analysis is illustrated. Reproducibility of wavelength settings are within +-0.5 A. Precision and sensitivities are at least as good as those obtained for single element determinations. (author)

  20. Optimization and development of analytical methods for the determination of new brominated flame retardants and polybrominated diphenyl ethers in sediments and suspended particulate matter

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, P. [VU University Amsterdam, Institute for Environmental Studies (IVM), Amsterdam (Netherlands); Institute for Reference Materials and Measurements, European Commission, Joint Research Centre, Retieseweg 111, 2440, Geel (Belgium); Brandsma, S.A.; Leonards, P.E.G.; Boer, J. de [VU University Amsterdam, Institute for Environmental Studies (IVM), Amsterdam (Netherlands)

    2011-05-15

    With more stringent legislation on brominated flame retardants, it is expected that increasing amounts of substitutes would replace polybrominated diphenylethers (PBDEs). Therefore, the development and optimization of analytical methodologies that allow their identification and quantification are of paramount relevance. This work describes the optimization of an analytical procedure to determine pentabromochlorocyclohexane, tetrabromo-o-chlorotoluene, 2,3,5,6-tetrabromo-p-xylene, tetrabromophthalic anhydride, 2,3,4,5,6-pentabromotoluene, tris(2,3-dibromopropyl)phosphate, decabromodiphenylethane and 1,2-bis(2,4,6-tribromophenoxy)ethane together with PBDEs in sediments and in suspended particulate matter. This method comprises a pressurized liquid extraction followed by three cleanup steps (gel permeation chromatography and solid phase extraction on Oasis trademark HLB and on silica cartridges). Gas chromatography-mass spectrometry, using electron capture negative chemical ionization, is used for the final analysis. The proposed method provides recoveries >85%. The method was applied to sediment and suspended particulate matter samples from different locations in the Western Scheldt estuary (the Netherlands). To the best of our knowledge, this is the first time that the occurrence of the additive flame retardants 2,3,5,6-tetrabromo-p-xylene, 3,4,5,6-tetrabromo-o-chlorotoluene and 2,3,4,5,6-pentabromochlorocyclohexane is reported in the literature. The concentrations of these new flame retardants ranged from 0.05 to 0.30 {mu}g/kg dry weight. (orig.)

  1. Legacy and emerging brominated flame retardants in China: A review on food and human milk contamination, human dietary exposure and risk assessment.

    Science.gov (United States)

    Shi, Zhixiong; Zhang, Lei; Li, Jingguang; Wu, Yongning

    2018-05-01

    Brominated flame retardants (BFRs) are a large group of widely used chemicals, which have been produced and used since 1970s. As a consequence of substantial and long-term usage, BFRs have been found to be ubiquitous in humans, wildlife, and abiotic matrices around the world. Although several reports have reviewed BFRs contamination in general, none have focused specifically on foods and human milk, and the corresponding dietary exposure. Foods (including human milk) have long been recognized as a major pathway of BFRs intake for non-occupationally exposed persons. This review summarizes most available BFRs data in foods and human milk from China in recent years, and emphasizes several specific aspects, i.e., contamination levels of legacy and emerging BFRs, dietary exposure assessment and related health concerns, comparison between various BFRs, and temporal changes in BFRs contamination. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Widespread detection of a brominated flame retardant, hexabromocyclododecane, in expanded polystyrene marine debris and microplastics from South Korea and the Asia-Pacific coastal region

    International Nuclear Information System (INIS)

    Jang, Mi; Shim, Won Joon; Han, Gi Myung; Rani, Manviri; Song, Young Kyoung; Hong, Sang Hee

    2017-01-01

    The role of marine plastic debris and microplastics as a carrier of hazardous chemicals in the marine environment is an emerging issue. This study investigated expanded polystyrene (EPS, commonly known as styrofoam) debris, which is a common marine debris item worldwide, and its additive chemical, hexabromocyclododecane (HBCD). To obtain a better understanding of chemical dispersion via EPS pollution in the marine environment, intensive monitoring of HBCD levels in EPS debris and microplastics was conducted in South Korea, where EPS is the predominant marine debris originate mainly from fishing and aquaculture buoys. At the same time, EPS debris were collected from 12 other countries in the Asia-Pacific region, and HBCD concentrations were measured. HBCD was detected extensively in EPS buoy debris and EPS microplastics stranded along the Korean coasts, which might be related to the detection of a quantity of HBCD in non-flame-retardant EPS bead (raw material). The wide detection of the flame retardant in sea-floating buoys, and the recycling of high-HBCD-containing EPS waste inside large buoys highlight the need for proper guidelines for the production and use of EPS raw materials, and the recycling of EPS waste. HBCD was also abundantly detected in EPS debris collected from the Asia-Pacific coastal region, indicating that HBCD contamination via EPS debris is a common environmental issue worldwide. Suspected tsunami debris from Alaskan beaches indicated that EPS debris has the potential for long-range transport in the ocean, accompanying the movement of hazardous chemicals. The results of this study indicate that EPS debris can be a source of HBCD in marine environments and marine food web. - Highlights: • A brominated flame retardant, HBCD, was assessed in EPS debris and microplastics. • HBCD was widely detected in EPS debris from the Asia-Pacific coastal region. • Additive HBCD are dispersed via EPS pollution in marine environments. • EPS debris can be a

  3. Preparation of poly(trimethyl-2-methacroyloxyethylammonium chloride-co-ethylene glycol dimethacrylate) monolith and its application in solid phase microextraction of brominated flame retardants.

    Science.gov (United States)

    Yang, Ting-ting; Zhou, Lin-feng; Qiao, Jun-qin; Lian, Hong-zhen; Ge, Xin; Chen, Hong-yuan

    2013-05-24

    A capillary poly(trimethyl-2-methacroyloxyethylammonium chloride-co-ethylene glycol dimethacrylate) monolith was in situ synthesized by thermally initiated free radical co-polymerization using trimethyl-2-methacroyloxyethylammonium chloride (MATE) and ethylene glycol dimethacrylate (EGDMA) as functional monomer and cross-linker, respectively. N,N-dimethylformamide and polyethylene glycol 6000 were used as solvent and porogen, respectively. The morphology and porous structure of the resulting monoliths were assessed by scanning electron microscope. In order to prepare practically useful poly(MATE-co-EGDMA) monoliths with low flow resistance and good mechanical strength, some parameters such as PEG-6000 to DMF ratio, total monomer to porogen ratio, and crosslinker to monomer ratio were optimized systematically. Moreover, the extraction mechanism was evaluated using two series of compounds, alkylbenzenes and weak acids, as model compounds on poly(MATE-co-EGDMA) monoliths as liquid chromatographic stationary phase. Finally, the monoliths were applied as the solid phase microextraction medium, and a simple off-line method for simultaneous determination of three brominated flame retardants, 2,4,6-tribromophenol (TBP), tetrabromobisphenol A (TBBPA) and 4,4'-dibrominated diphenyl ether (DBDPE), in environmental waters was developed by coupling the polymer monolith microextraction to HPLC with UV detection. The regression equations for these three brominated flame retardants showed good linearity from their limit of quantification to 5000ng/mL. The limits of detection were 0.20, 0.15 and 0.10ng/mL for TBP, TBBPA and DBDPE, respectively. The recovery of the proposed method was 78.7-106.1% with intra-day relative standard deviation of 1.3-4.4%. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Effects of prenatal exposure to hydoxylated PCB metabolites and some brominated flame retardants on the development of rats

    Energy Technology Data Exchange (ETDEWEB)

    Buitenhuis, C.; Cenijn, P.C.; Velzen, M. van; Gutleb, A.C.; Legler, J. [Institute for Environmental Studies (IVM), Amsterdam (Netherlands); Lilienthal, H. [Heinrich Univ., Duesseldorf (Germany). Dept. Neurobehavioural Toxicology, Medical Institute of Environmental Hygiene; Malmberg, T.; Bergman, Aa. [Stockholm Univ. (Sweden). Dept. of Environmental Chemistry; Brouwer, A.

    2004-09-15

    Possible human health effects from low-level exposure to environmental chemicals are an issue that has attracted much attention. Environmental compounds that may play a role are those that may disrupt endocrine function. Organohalogen compounds, and in particular their hydroxylated metabolites, show a striking resemblance to steroid hormones.The main objective of this research is to investigate comparative pathways of early life-stage exposure and long-term effects for several classes of organohalogens, including polychlorinated biphenyls (PCBs) and flame retardants, polybrominated bisphenols and -diphenylethers, and their hydroxylated metabolites. Due to their prevalence in human plasma, the hydroxylated PCB metabolites 4-OH-CB107 and 4-OH-CB187, as well as 6-OH-BDE47 and 2,4,6- tribromophenol, were selected as test compounds. BDE 47 has been included as a test compound due to its relatively high levels in the environment and biota, whereas tetrabromobisphenol A (TBBPA) was selected because of its high volume production. The in vivo studies involved prenatal exposure of rats to test compounds during critical stages of gonadal development and were focussed on low dose effects. Several endpoints were investigated, including endocrine (thyroid and sex steroid hormones) effects, developmental landmarks, sexual and neurobehavioural development. Blood plasma and tissue levels of test compounds were analysed to determine transplacental transfer of (hydroxylated) organohalogens.

  5. Mode Selection in Flame-Vortex driven Combustion Instabilities

    KAUST Repository

    Speth, Ray

    2011-01-04

    In this paper, we investigate flame-vortex interaction in a lean premixed, laboratory scale, backward-facing step combustor. Two series of tests were conducted, using propane/hydrogen mixtures and carbon monoxide/hydrogen mixtures as fuels, respectively. Pressure measurements and high speed particle imaging velocimetry (PIV) were employed to generate pressure response curves as well as the images of the velocity field and the flame brush. We demonstrate that the step combustor exhibits several operating modes depending on the inlet conditions and fuel composition, characterized by the amplitude and frequency of pressure oscillations along with distinct dynamic flame shapes. We propose a model in which the combustor\\'s selection of the acoustic mode is governed by a combustion-related time delay inversely proportional to the flame speed. Our model predicts the transition between distinct operating modes. We introduce non-dimensional parameters characterizing the flame speed and stretch rate, and develop a relationship between these quantities at the operating conditions corresponding to each mode transition. Based on this relationship, we show that numerically-calculated density-weighted strained flame speed can be used to collapse the combustion dynamics data over the full range of conditions (inlet temperature, fuel composition, and equivalence ratio). Finally, we validate our strain flame based model by measuring the strain rate using the flame image and the velocity field from the PIV measurement. Our results show that the measured strain rates lie in the same range as the critical values at the transitions among distinct modes as those predicted by our model.

  6. Transcriptional and epigenetic mechanisms underlying enhanced in vitro adipocyte differentiation by the brominated flame retardant BDE-47

    DEFF Research Database (Denmark)

    Kamstra, Jorke H; Hruba, Eva; Blumberg, Bruce

    2014-01-01

    Recent studies suggest that exposure to endocrine-disrupting compounds (EDCs) may play a role in the development of obesity. EDCs such as the flame retardant 2,2',4,4'-tetrabrominated diphenyl ether (BDE-47) have been shown to enhance adipocyte differentiation in the murine 3T3-L1 model. The mech......Recent studies suggest that exposure to endocrine-disrupting compounds (EDCs) may play a role in the development of obesity. EDCs such as the flame retardant 2,2',4,4'-tetrabrominated diphenyl ether (BDE-47) have been shown to enhance adipocyte differentiation in the murine 3T3-L1 model....... The mechanisms by which EDCs direct preadipocytes to form adipocytes are poorly understood. Here, we examined transcriptional and epigenetic mechanisms underlying the induction of in vitro adipocyte differentiation by BDE-47. Quantitative high content microscopy revealed concentration-dependent enhanced...

  7. Critical review of soil contamination by polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (NBFRs); concentrations, sources and congener profiles.

    Science.gov (United States)

    McGrath, Thomas J; Ball, Andrew S; Clarke, Bradley O

    2017-11-01

    Polybrominated diphenyl ethers (PBDEs) have been used in a broad array of polymeric materials such as plastics, foams, resins and adhesives to inhibit the spread of fires since the 1970s. The widespread environmental contamination and well documented toxic effects of PBDEs have led to bans and voluntary withdrawals in many jurisdictions. Replacement novel brominated flame retardants (NBFRs) have, however, exhibited many of the same toxic characteristics as PBDEs and appear to share similar environmental fate. This paper presents a critical review of the scientific literature regarding PBDE and NBFR contamination of surface soils internationally, with the secondary objective of identifying probable pollution sources. An evaluation of NBFR distribution in soil was also conducted to assess the suitability of the newer compounds as replacements for PBDEs, with respect to their land contamination potential. Principle production of PBDEs and NBFRs and their consequent use in secondary polymer manufacture appear to be processes with strong potential to contaminate surrounding soils. Evidence suggests that PBDEs and NBFRs are also released from flame retarded products during disposal via landfill, dumping, incineration and recycling. While the land application of sewage sludge represents another major pathway of soil contamination it is not considered in this review as it is extensively covered elsewhere. Both PBDEs and NBFRs were commonly detected at background locations including Antarctica and northern polar regions. PBDE congener profiles in soil were broadly representative of the major constituents in Penta-, Octa- and Deca-BDE commercial mixtures and related to predicted market place demand. BDE-209 dominated soil profiles, followed by BDE-99 and BDE-47. Although further research is required to gain baseline data on NBFRs in soil, the current state of scientific literature suggests that NBFRs pose a similar risk to land contamination as PBDEs. Copyright © 2017

  8. Chlorinated organophosphate and “legacy” brominated flame retardants in UK waste soft furnishings: A preliminary study

    Directory of Open Access Journals (Sweden)

    William A. Stubbings

    2016-12-01

    Full Text Available The Furniture and Furnishings (Fire Safety Regulations 1988 is the major driver for the use of chemical flame retardants (FRs in soft furnishings marketed in the UK. While these regulations specify the level of flame retardancy required, they do not specify how such levels should be achieved. Consequently, it remains unclear which FRs are present in UK soft furnishings. This is important not only to help assess what FRs we may be exposed to currently, but which FRs are currently entering the waste stream with concomitant potential for release into the environment. To address this data gap, concentrations of polybrominated diphenyl ethers (PBDEs, hexabromocyclododecane (HBCDD and a range of chlorinated organophosphate flame retardants (OPFRs were measured in samples of domestic and office waste soft furnishings products entering the UK waste stream in 2011 and 2012. This preliminary study measured the FR content of: carpets (n = 4, curtains (n = 7, mattress fabrics (n = 2, furniture foam (n = 9, and furniture upholstery textiles (n = 10. Polybrominated diphenyl ethers (PBDEs and hexabromocyclododecane (HBCDD were not found at significant concentrations (below detection limits in most samples in any of the twenty two analysed products. In contrast, 7 of the 9 furniture foam samples were treated with tris(2-chloroisopropylphosphate (TCIPP at a mean concentration of 1.9% w/w, with another single foam sample containing tris(1,3-dichloroisopropylphosphate (TDCIPP and tris(2-chloroethylphosphate (TCEP at 1.1 and 0.5% respectively. By comparison, PBDE concentrations are within the range reported previously for UK indoor dust [18], rather than the percent by weight levels required to impart flame retardancy.

  9. Occurrence and Source Effect of Novel Brominated Flame Retardants (NBFRs) in Soils from Five Asian Countries and Their Relationship with PBDEs.

    Science.gov (United States)

    Li, Wen-Long; Ma, Wan-Li; Zhang, Zi-Feng; Liu, Li-Yan; Song, Wei-Wei; Jia, Hong-Liang; Ding, Yong-Sheng; Nakata, Haruhiko; Minh, Nguyen Hung; Sinha, Ravindra Kumar; Moon, Hyo-Bang; Kannan, Kurunthachalam; Sverko, Ed; Li, Yi-Fan

    2017-10-03

    This paper presents the first comprehensive survey of 19 novel brominated flame retardants (NBFRs) in soil samples collected among five Asian countries. High variability in concentrations of all NBFRs was found in soils with the geometric mean (GM) values ranging from 0.50 ng/g dry weight (dw) in Vietnam to 540 ng/g dw in the vicinity of a BFR manufacturer in China. In urban, rural, and background locations, the GM concentrations of ∑ 19 NBFRs decreased in the order of Japan > South Korea > China > India > Vietnam. Correlations among different NBFR compounds were positive and statistically significant (p e-waste sites. For the first time, this study demonstrates a "point source fractionation effect" for NBFRs and PBDEs. The concentrations of all NBFRs and PBDEs were negatively and significantly correlated with the distance from BFR-related industrial and e-waste regions. Positive and significant correlation between population density and NBFR concentrations in soils was identified. Our study revealed that the primary sources effects were stronger than the secondary sources effects in controlling the levels and distribution of NBFRs and PBDEs in soils in these five Asian countries.

  10. Some commonly used brominated flame retardants cause Ca2+-ATPase inhibition, beta-amyloid peptide release and apoptosis in SH-SY5Y neuronal cells.

    Directory of Open Access Journals (Sweden)

    Fawaz Al-Mousa

    Full Text Available Brominated flame retardants (BFRs are chemicals commonly used to reduce the flammability of consumer products and are considered pollutants since they have become widely dispersed throughout the environment and have also been shown to bio-accumulate within animals and man. This study investigated the cytotoxicity of some of the most commonly used groups of BFRs on SH-SY5Y human neuroblastoma cells. The results showed that of the BFRs tested, hexabromocyclododecane (HBCD, tetrabromobisphenol-A (TBBPA and decabromodiphenyl ether (DBPE, all are cytotoxic at low micromolar concentrations (LC(50 being 2.7 ± 0.7 µM, 15 ± 4 µM and 28 ± 7 µM, respectively. They induced cell death, at least in part, by apoptosis through activation of caspases. They also increased intracellular [Ca(2+] levels and reactive-oxygen-species within these neuronal cells. Furthermore, these BFRs also caused rapid depolarization of the mitochondria and cytochrome c release in these neuronal cells. Elevated intracellular [Ca(2+] levels appear to occur through a mechanism involving microsomal Ca(2+-ATPase inhibition and this maybe responsible for Ca(2+-induced mitochondrial dysfunction. In addition, µM levels of these BFRs caused β-amyloid peptide (Aβ-42 processing and release from these cells with a few hours of exposure. These results therefore shows that these pollutants are both neurotoxic and amyloidogenic in-vitro.

  11. New priority substances of the European Water Framework Directive: biocides, pesticides and brominated flame retardants in the aquatic environment of Denmark.

    Science.gov (United States)

    Vorkamp, Katrin; Bossi, Rossana; Bester, Kai; Bollmann, Ulla E; Boutrup, Susanne

    2014-02-01

    The biocides cybutryn (Irgarol) and terbutryn, the herbicides aclonifen and bifenox, the insecticides cypermethrin and heptachlor/heptachlor epoxide and the brominated flame retardant hexabromocyclododecane (HBCD) are new priority substances of the Water Framework Directive of the European Union. In order to gain knowledge about their presence in the aquatic environment in an off-season situation with regard to pesticide and biocide applications, these substances were analysed in freshwater, seawater and fish samples from Denmark. Aclonifen, bifenox, cypermethrin and heptachlor were below the limits of detection (LODs) in all samples. However, the LODs for cypermethrin and heptachlor exceeded the annual average environmental quality standards (AA-EQSs). Cybutryn, terbutryn, heptachlor epoxide and HBCD were detected in the majority of samples, with detection frequencies of 100% for heptachlor epoxide and HBCD in water and 90% in fish. No concentration was above maximum allowable concentration (MAC)-EQS values, but AA-EQS values were exceeded for all four compounds by several samples, including 100% of the water samples with regard to heptachlor epoxide. Methodological issues remain for cypermethrin, and to a certain extent for heptachlor/heptachlor epoxide, for which water LODs were above AA-EQSs although a water volume of 12L was combined with very sensitive high resolution mass spectrometry. © 2013.

  12. Exponential increases of the brominated flame retardants, polybrominated diphenyl ethers, in the Canadian Arctic from 1981 to 2000.

    Science.gov (United States)

    Ikonomou, Michael G; Rayne, Sierra; Addison, Richard F

    2002-05-01

    A suite of 37 polybrominated diphenyl ether (PBDE) congeners and all of the homologue groups from mono- to deca-brominated were determined in ringed seal (Phoca hispida) blubber collected from subsistence hunts in the Canadian Arctic in 1981, 1991, 1996, and 2000. Total PBDE (sum(PBDE)) concentrations have increased exponentially over this period in male ringed seals aged 0-15 years. Penta- and hexa-BDEs are increasing at approximately the same rate (t2 = 4.7 and 4.3 years, respectively) and more rapidly than tetra-BDEs (t2 = 8.6 years) and tri-BDEs (t2 = infinity) in this age/sex grouping. In contrast to declining PBDE concentrations since 1997 in human milk from Sweden, sum(PBDE) concentrations in arctic ringed seals continue to increase exponentially similar to worldwide commercial penta-BDE production. PBDE congener profiles in male ringed seals aged 0-15 years from 1991 to 2000 also differ significantly from other aquatic organisms and semipermeable membrane devices collected from temperate coastal regions of British Columbia. While PBDE concentrations are 50 times lower than those of mono-ortho and non-ortho PCBs, and approxiamately 500 times higher than PCDD/Fs, our data indicate that, at current rates of bioaccumulation, PBDEs will surpass PCBs to become the most prevalent organohalogen compound in Canadian arctic ringed seals by 2050.

  13. Developmental exposure to low concentrations of two brominated flame retardants, BDE-47 and BDE-99, causes life-long behavioral alterations in zebrafish.

    Science.gov (United States)

    Glazer, Lilah; Wells, Corinne N; Drastal, Meghan; Odamah, Kathryn-Ann; Galat, Richard E; Behl, Mamta; Levin, Edward D

    2018-05-01

    Polybrominated diphenyl ethers (PBDEs) were widely used as flame retardants until the early 2000s, mainly in home furnishings and electronics. The persistence of PBDEs in the environment leads to continued ubiquitous exposure to low levels, with infants and children experiencing higher exposures than adults. Accumulating evidence suggest that low-level exposures during early life stages can affect brain development and lead to long-term behavioral impairments. We investigated the effects of zebrafish exposure to low doses of the two prominent PBDEs; 2,2',4,4',5,-Pentabromodiphenyl ether (BDE-99) and 2,2',4,4',-Tetrabromodiphenyl ether (BDE-47), during embryo-development on short- and long-term behavioral endpoints. We included the organophosphate pesticide chlorpyrifos (CPF) due to its well documented neurotoxicity across species from zebrafish to humans. Zebrafish embryos were exposed to the following individual treatments; 0.1% DMSO (vehicle control); 0.3μM CPF; 0.01, 0.03, 0.1, 0.3μM BDE-47; 0.003, 0.03, 0.3, 1, 3, 10, 20μM BDE-99 from 5 until 120h post fertilization (hpf). Low exposure levels were determined as those not causing immediate overt toxicity, and behavior assays were conducted in the low-level range. At 144 hpf the larvae were tested for locomotor activity. At approximately 6 months of age adult zebrafish were tested in a behavioral battery including assays for anxiety-related behavior, sensorimotor response and habituation, social interaction, and predator avoidance. In the short-term, larval locomotor activity was reduced in larvae treated with 0.3μM CPF and 0.1μM BDE-47. BDE-99 treatment caused non-monotonic dose effects, with 0.3μM causing hyperactivity and 1μM or higher causing hypoactivity. In the long-term, adult anxiety-related behavior was reduced in all treatments as measured in both the novel tank dive test and tap test. We show that exposure of zebrafish embryos to low concentrations of the brominated flame retardants BDE-47 and

  14. Simultaneous analysis of historical, emerging and novel brominated flame retardants in food and feed using a common extraction and purification method.

    Science.gov (United States)

    Bichon, Emmanuelle; Guiffard, Ingrid; Vénisseau, Anaïs; Lesquin, Elodie; Vaccher, Vincent; Marchand, Philippe; Le Bizec, Bruno

    2018-04-13

    Brominated Flame Retardants (BFRs) are still widely used for industrial purposes. These contaminants may enter the food chain where they mainly occur in food of animal origin. The aim of our work was to provide a unique method able to quantify the widest range of BFRs in feed and food items. After freeze-drying and grinding, a pressurized liquid extraction was carried out. The extract was purified on acidified silica, Florisil ® and carbon columns, the four separated fractions were analyzed by gas and liquid chromatography coupled to high resolution and tandem mass spectrometry. Isotopic dilution was preferentially used when commercial labelled compounds were available. Analytical sensitivity was in accordance with the expectations of Recommendation 2014/118/EU for PBDEs, HBCDDs, TBBPA, TBBPA-bME, EHTBB, BEHTEBP and TBBPA-bME. Additional BFRs were included in this analytical method with the same level of performances (LOQs below 0.01 ng g -1 ww). These are PBBs, pTBX, TBCT, PBBz, PBT, PBEB, HBBz, BTBPE, OBIND and T23BPIC. However, some of the BFRs listed in Recommendation 2014/118/EU are not yet covered by our analytical method, i.e. TBBPA-bOHEE, TBBPA-bAE, TBBPA-bGE, TBBPA-bDiBPrE, TBBPS, TBBPS-bME, TDBPP, EBTEBPI, HBCYD and DBNPG. The uncertainty measurement was fully calculated for 21 of the 31 analytes monitored in the method. Reproducibility uncertainty was below 23% in isotopic dilution. Certified reference materials are now required to better characterize the trueness of this method, which was applied in the French National Control Plans. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Contamination of indoor dust and air by polychlorinated biphenyls and brominated flame retardants and relevance of non-dietary exposure in Vietnamese informal e-waste recycling sites.

    Science.gov (United States)

    Tue, Nguyen Minh; Takahashi, Shin; Suzuki, Go; Isobe, Tomohiko; Viet, Pham Hung; Kobara, Yuso; Seike, Nobuyasu; Zhang, Gan; Sudaryanto, Agus; Tanabe, Shinsuke

    2013-01-01

    This study investigated the occurrence of polychlorinated biphenyls (PCBs), and several additive brominated flame retardants (BFRs) in indoor dust and air from two Vietnamese informal e-waste recycling sites (EWRSs) and an urban site in order to assess the relevance of these media for human exposure. The levels of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 1,2-bis-(2,4,6-tribromophenoxy)ethane (BTBPE) and decabromodiphenyl ethane (DBDPE) in settled house dust from the EWRSs (130-12,000, 5.4-400, 5.2-620 and 31-1400 ng g(-1), respectively) were significantly higher than in urban house dust but the levels of PCBs (4.8-320 ng g(-1)) were not higher. The levels of PCBs and PBDEs in air at e-waste recycling houses (1000-1800 and 620-720 pg m(-3), respectively), determined using passive sampling, were also higher compared with non-e-waste houses. The composition of BFRs in EWRS samples suggests the influence from high-temperature processes and occurrence of waste materials containing older BFR formulations. Results of daily intake estimation for e-waste recycling workers are in good agreement with the accumulation patterns previously observed in human milk and indicate that dust ingestion contributes a large portion of the PBDE intake (60%-88%), and air inhalation to the low-chlorinated PCB intake (>80% for triCBs) due to their high levels in dust and air, respectively. Further investigation of both indoor dust and air as the exposure media for other e-waste recycling-related contaminants and assessment of health risk associated with exposure to these contaminant mixtures is necessary. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Novel brominated flame retardants in food composites and human milk from the Chinese Total Diet Study in 2011: Concentrations and a dietary exposure assessment.

    Science.gov (United States)

    Shi, Zhixiong; Zhang, Lei; Li, Jingguang; Zhao, Yunfeng; Sun, Zhiwei; Zhou, Xianqing; Wu, Yongning

    2016-11-01

    On the basis of the fifth Chinese total diet study (TDS) performed in 2011, the dietary exposure of the Chinese population to novel brominated flame retardants (NBFRs) was assessed. Six NBFRs were determined in 80 composite samples from four animal origin food groups and 29 pooled human milk samples. Based on gas chromatography-negative chemical ionization mass spectrometry (GC-NCI/MS) analysis, the levels of the total NBFRs ranged from human milk samples. Decabromodiphenyl ethane (DBDPE), with mean levels of 9.03ng/g lw in food composites and 8.06ng/g lw in human milk, was the most abundant compound in the total NBFRs. No obvious spatial distribution patterns in China were observed in food samples or human milk. The average estimated daily intake (EDI) of total NBFRs via food consumption for a "standard Chinese man" was 4.77ng/kg bodyweight (bw)/day, with a range of 0.681 to 18.9ng/kgbw/day. Meat and meat products were the main dietary source of NBFRs, although levels of NBFRs in aquatic food were found to be the highest among the four food groups. The average EDI of total NBFRs for nursing infants was 38.4ng/kgbw/day, with a range of 17.4 to 113ng/kgbw/day, which was approximately eight-fold higher than the EDI for adults, suggesting the heavy body burden of NBFRs on nursing infants. The levels and EDI of DBDPE in the present study were similar to or higher than those of legacy BFRs (i.e., PBDEs and HBCD) in the TDS 2007, indicating that DBDPE, as a main alternative to PBDEs, might have become the primary BFR used in China. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Comparative antioxidant status in freshwater fish Carassius auratus exposed to six current-use brominated flame retardants: A combined experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Mingbao; Qu, Ruijuan; Wang, Chao; Wang, Liansheng; Wang, Zunyao, E-mail: wangzun315cn@163.com

    2013-09-15

    Highlights: •A combined experimental and theoretical approach was used for risk assessments of six BFRs in fish. •Oxidative stress biomarkers were measured for toxicity identification. •Toxicity order was proposed via the integrated biomarker response. •Theoretical calculations were performed to analyze the BFRs toxicity. -- Abstract: Decabromodiphenyl ether (BDE-209) and several non-polybrominated diphenyl ether (PBDE) brominated flame retardants (BFRs), such as tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD), decabromodiphenyl ethane (DBDPE), hexabromobenzene (HBB) and pentabromotoluene (PBT), are persistent halogenated contaminants ubiquitously detected in aquatic systems. However, data on comparative toxicological effects of these BFRs are lacking for fish. In this study, a combined experimental and theoretical approach was used to compare and analyze the effects of these BFRs on biochemical biomarkers in liver of Carassius auratus injected intraperitoneally with different doses (10 and 100 mg/kg) for 7, 14 and 30 days. Oxidative stress was evoked evidently for the prolonged exposure, represented by the significantly altered indices (superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione, and malondialdehyde). The integrated biomarker response (IBR) index ranked biotoxicity as: PBT > HBB > HBCD > TBBPA > BDE-209 > DBDPE. Quantum chemical calculations (electronic parameters, frontier molecular orbitals, and Wiberg bond order) were performed for theoretical analysis. Notably, some descriptors were correlated with the toxicity order, probably implying the existence of a potential structure–activity relationship when more BFRs were included. Besides, theoretical calculations also provided some valuable information regarding the molecular characteristics and metabolic pathways of these current-use BFRs, which may facilitate the understanding on their environmental behavior and fate. Overall, this study adopted a combined

  18. Brominated flame retardants in U.S. biosolids from the EPA national sewage sludge survey and chemical persistence in outdoor soil mesocosms

    Science.gov (United States)

    Venkatesan, Arjun K.; Halden, Rolf U.

    2014-01-01

    We determined national baseline levels and release inventories of 77 traditional and novel brominated flame retardants (BFRs) in biosolids composites (prepared from 110 samples) from the U.S. Environmental Protection Agency’s 2001 national sewage sludge survey (NSSS). Additionally, analyses were performed on archived samples from a 3-year outdoor mesocosm study to determine the environmental persistence of BFRs in biosolids-amended soil. The total polybrominated diphenylether (PBDE) concentration detected in biosolids composites was 9,400±960 μg/kg dry weight, of which deca-BDE constituted 57% followed by nona- and penta-BDE at 18 and 13%, respectively. The annual mean loading rate estimated from the detected concentrations and approximate annual biosolids production and disposal numbers in the U.S., of the sum of PBDEs and non-BDE BFRs was calculated to be 47,900–60,100 and 12,900–16,200 kg/year, of which 24,000–36,000 and 6,400–9,700 kg/year are applied on land, respectively. Mean concentration of PBDEs were higher in the 2001 samples compared to levels reported in EPA’s 2006/7 Targeted NSSS, reflecting on-going efforts in phasing-out PBDEs in the U.S. In outdoor soil mesocosms, >99% of the initial BFRs mass in the biosolids/soil mixtures (1:2) persisted over the monitoring duration of three years. Estimates of environmental releases may be refined in the future by analyzing individual rather than composited samples, and by integrating currently unavailable data on disposal of biosolids on a plant-specific basis. This study informs the risk assessment of BFRs by furnishing national inventories of BFR occurrence and environmental release via biosolids application on land. PMID:24607311

  19. Comparative toxicity of a brominated flame retardant (tetrabromobisphenol A) on microalgae with single and multi-species bioassays.

    Science.gov (United States)

    Debenest, Timothée; Petit, Anne-Nöelle; Gagné, François; Kohli, Mohan; Nguyen, Nien; Blaise, Christian

    2011-09-01

    The potential threat of emerging chemicals to the aquatic flora is a major issue. The purpose of the study was to develop a multispecies microalgae test in order to determine the impact of species interactions on the cytoxicity of an emergent toxic contaminant: the tetrabromobisphenol A (TBBPA). Single and multi-species tests were thus performed to study the effects of this flame retardant on two microalgae (Pseudokirchneriella subcapitata and Nitzschia palea) commonly observed in freshwater. A synthetic medium was designed to allow the growth of both species. The algae were exposed to 1.8, 4.8, 9.2, 12.9 and 16.5 μM of TBBPA for 72 h. After staining with fluorescein diacetate (FDA), viable cells of each alga species were analyzed by flow cytometry based on chlorophyll autofluorescence and intracellular esterase activity. Density and abundance of viable cells were assessed to follow the population growth and the cell viability. In TBBPA treated samples, the growth of the two microalgae was significantly inhibited at the three highest concentrations (9.2, 12.9 and 16.5 μM) in the two tests. At the end of the experiment (t=72 h), the cell viability was also significantly smaller at these concentrations. The decreases of growth rate and viable cell abundance in TBBPA treated populations of N. palea were significantly higher in multi-species test in comparison with the single-species test. No significant differences were noticed between the two tests for P. subcapitata populations exposed to TBBPA. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  20. Mode Selection in Flame-Vortex driven Combustion Instabilities

    KAUST Repository

    Speth, Ray; Hong, Seung Hyuck; Shanbogue, Santosh; Ghoniem, Ahmed

    2011-01-01

    is governed by a combustion-related time delay inversely proportional to the flame speed. Our model predicts the transition between distinct operating modes. We introduce non-dimensional parameters characterizing the flame speed and stretch rate, and develop a

  1. Magnetic solid phase extraction of brominated flame retardants and pentachlorophenol from environmental waters with carbon doped Fe{sub 3}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jing [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering and Center of Materials Analysis, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, College of Chemistry and Materials Science, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023 (China); Li, Jia-yuan; Qiao, Jun-qin [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering and Center of Materials Analysis, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Cui, Shi-hai [Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, College of Chemistry and Materials Science, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023 (China); Lian, Hong-zhen, E-mail: hzlian@nju.edu.cn [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering and Center of Materials Analysis, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Chen, Hong-yuan [State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering and Center of Materials Analysis, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)

    2014-12-01

    Graphical abstract: - Highlights: • Magnetic Fe{sub 3}O{sub 4}/C nanospheres were used in MSPE of BFRs and PCP from water samples. • The method shows merits of simpleness, reliableness and environmental friendliness. • The bonding between Fe{sub 3}O{sub 4} and coated organic carbon has been demonstrated in Fe{sub 3}O{sub 4}/C. • The straight influences of synthesis conditions of Fe{sub 3}O{sub 4}/C on MSPE were investigated. • The extraction characteristics of Fe{sub 3}O{sub 4}/C nanoparticles were further elucidated. - Abstract: Carbon doped Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4}/C) prepared by a facile hydrothermal reaction of glucose with iron resource have been applied as magnetic solid-phase extraction (MSPE) sorbent, for the first time, to extract trace brominated flame retardants (BFRs) and pentachlorophenol (PCP) from environmental waters. Various MSPE parameters were optimized including amount of Fe{sub 3}O{sub 4}/C nanoparticles, pH of sample solution, enrichment factor of analytes and reusability of Fe{sub 3}O{sub 4}/C sorbent. The reliability of the MSPE method was evaluated by the recoveries of BFRs and PCP in spiked water samples. Good recoveries (80.0–110.0%) were achieved with the relative standard deviations range from 0.3% to 6.8%. In this paper, the extraction characteristics of Fe{sub 3}O{sub 4}/C sorbent were further elucidated. It is found that the adsorption process of Fe{sub 3}O{sub 4}/C to analytes predominates the MSPE efficiency. There is hybrid hydrophobic interaction and hydrogen bonding or dipole–dipole attraction between Fe{sub 3}O{sub 4}/C and analytes. Notably, the chemical components of carbon layer on the surface of Fe{sub 3}O{sub 4} nanoparticles were identified by X-ray photoelectron spectroscopy and thermogravimetry-mass spectrometry, and in consequence the covalent bonds between Fe{sub 3}O{sub 4} and the coated carbon have been observed. In addition, the straight influence of synthesis condition of Fe

  2. Magnetic solid phase extraction of brominated flame retardants and pentachlorophenol from environmental waters with carbon doped Fe3O4 nanoparticles

    International Nuclear Information System (INIS)

    Yang, Jing; Li, Jia-yuan; Qiao, Jun-qin; Cui, Shi-hai; Lian, Hong-zhen; Chen, Hong-yuan

    2014-01-01

    Graphical abstract: - Highlights: • Magnetic Fe 3 O 4 /C nanospheres were used in MSPE of BFRs and PCP from water samples. • The method shows merits of simpleness, reliableness and environmental friendliness. • The bonding between Fe 3 O 4 and coated organic carbon has been demonstrated in Fe 3 O 4 /C. • The straight influences of synthesis conditions of Fe 3 O 4 /C on MSPE were investigated. • The extraction characteristics of Fe 3 O 4 /C nanoparticles were further elucidated. - Abstract: Carbon doped Fe 3 O 4 nanoparticles (Fe 3 O 4 /C) prepared by a facile hydrothermal reaction of glucose with iron resource have been applied as magnetic solid-phase extraction (MSPE) sorbent, for the first time, to extract trace brominated flame retardants (BFRs) and pentachlorophenol (PCP) from environmental waters. Various MSPE parameters were optimized including amount of Fe 3 O 4 /C nanoparticles, pH of sample solution, enrichment factor of analytes and reusability of Fe 3 O 4 /C sorbent. The reliability of the MSPE method was evaluated by the recoveries of BFRs and PCP in spiked water samples. Good recoveries (80.0–110.0%) were achieved with the relative standard deviations range from 0.3% to 6.8%. In this paper, the extraction characteristics of Fe 3 O 4 /C sorbent were further elucidated. It is found that the adsorption process of Fe 3 O 4 /C to analytes predominates the MSPE efficiency. There is hybrid hydrophobic interaction and hydrogen bonding or dipole–dipole attraction between Fe 3 O 4 /C and analytes. Notably, the chemical components of carbon layer on the surface of Fe 3 O 4 nanoparticles were identified by X-ray photoelectron spectroscopy and thermogravimetry-mass spectrometry, and in consequence the covalent bonds between Fe 3 O 4 and the coated carbon have been observed. In addition, the straight influence of synthesis condition of Fe 3 O 4 /C nanoparticles including glucose concentration and hydrothermal reaction time on extraction performance for

  3. Advances in the study of current-use non-PBDE brominated flame retardants and dechlorane plus in the environment and humans

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The fate of the high production volume,currently in use,and not regulated non-polybrominated diphenyl ether(PBDE) flame retardants,such as tetrabromobisphenol A(TBBPA) ,hexabromocyclododecane(HBCD) and dechlorane plus(DP),and the alternative flame retardants of PBDE,such as BTBPE and DBDPE,in the environment has attracted increasing attention and aroused concern due to the increasing regulation and phasing-out of PBDEs.This paper reviews the distribution,bioaccumulation,human exposure and environmental behavior of those non-PBDE flame retardants in various environmental compartments.The data gaps and needs for future research are discussed.

  4. Applicability of Gas Chromatography (GC) Coupled to Triple-Quadrupole (QqQ) Tandem Mass Spectrometry (MS/MS) for Polybrominated Diphenyl Ether (PBDE) and Emerging Brominated Flame Retardant (BFR) Determinations in Functional Foods Enriched in Omega-3.

    Science.gov (United States)

    García-Bermejo, Ángel; Mohr, Susana; Herrero, Laura; González, María-José; Gómara, Belén

    2016-09-28

    This paper reports on the optimization, characterization, and applicability of gas chromatography coupled to triple-quadrupole tandem mass spectrometry (GC-QqQ(MS/MS)) for the determination of 14 polybrominated diphenylethers (PBDEs) and 2 emerging brominated flame retardants, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) and decabromodiphenylethane (DBDPE), in functional food samples. The method showed satisfactory precision and linearity with instrumental limits of detection (iLODs) ranging from 0.12 to 7.1 pg, for tri- to octa-BDEs and BTBPE, and equal to 51 and 20 pg for BDE-209 and DBDPE, respectively. The highest ΣBFR concentrations were found in fish oil supplements (924 pg/g fresh weight, fw), followed by biscuits (90 pg/g fw), vegetable oil supplements (46 pg/g fw), chicken eggs (45 pg/g fw), cow's milk (7.7 pg/g fw), and soy products (1.6 pg/g fw). BDE-47, BDE-99, and DBDPE were the most abundant compounds. Foodstuffs enriched with omega-3 presented concentrations similar to or even lower than those of conventional foods commercialized in Spain since 2000.

  5. Brominated flame retardants and organochlorine pollutants in aquatic and terrestrial predatory birds of Belgium: levels, patterns, tissue distribution and condition factors

    International Nuclear Information System (INIS)

    Jaspers, V.L.B.; Covaci, A.; Voorspoels, S.; Dauwe, T.; Eens, M.; Schepens, P.

    2006-01-01

    Liver and muscle samples from 7 species of aquatic and terrestrial predatory birds from Flanders (Belgium) were analysed for polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs) and organochlorine pesticides (OCPs). PCBs were the predominant compounds in our samples, which showed highest concentrations in the liver of barn owl (Tyto alba) and sparrowhawk (Accipiter nisus) (up to 1000 μg/g lipid weight). PBDEs could be determined in most samples at lower concentrations than PCBs (up to 64 μg/g lipid in sparrowhawk liver). Sparrowhawks had the highest levels of hexachlorobenzene, DDTs and PBDEs. In contrast, kestrels (Falco tinnunculus) had relatively low levels of most measured organochlorines. BDE 47 was the most abundant congener in heron (Ardea cinerea) and grebe (Podiceps cristatus), while BDE 47, 99 and 153 were equally important in the terrestrial species. BDE 183 and BDE 209 were only measured in the terrestrial birds. These results indicate that terrestrial birds may be more exposed to higher brominated BDE congeners than aquatic species. - Aquatic and terrestrial predatory birds show different accumulation profiles of PBDEs

  6. Efficient and selective α-bromination of carbonyl compounds with N-bromosuccinimide under microwave

    KAUST Repository

    Guan, Xiao-Yu; Al-Misba'a, Zahra; Huang, Kuo-Wei

    2014-01-01

    A highly efficient method for the synthesis of α-halocarbonyl compounds has been achieved via selective monobromination of aromatic and aliphatic carbonyl compounds with N-bromosuccinimide catalyzed by p-toluenesulfonic acid under microwave irradiation within 30 min.

  7. Efficient and selective α-bromination of carbonyl compounds with N-bromosuccinimide under microwave

    KAUST Repository

    Guan, Xiao-Yu

    2014-02-07

    A highly efficient method for the synthesis of α-halocarbonyl compounds has been achieved via selective monobromination of aromatic and aliphatic carbonyl compounds with N-bromosuccinimide catalyzed by p-toluenesulfonic acid under microwave irradiation within 30 min.

  8. Bromination of Phenol

    Science.gov (United States)

    Talbot, Christopher

    2013-01-01

    This "Science note" examines the bromination of phenol, a reaction that is commonly taught at A-level and IB (International Baccalaureate) as an example of electrophilic substitution. Phenol undergoes bromination with bromine or bromine water at room temperature. A white precipitate of 2,4,6-tribromophenol is rapidly formed. This…

  9. 母乳中溴代/氯代阻燃剂及其代谢产物的分析检测方法%Determination of Chlorinated/Brominated Flame Retardants and their Metabolites in Breast Milk

    Institute of Scientific and Technical Information of China (English)

    贲玉婕; 李龙; 王文月; 李兴红; 田媛; 徐晓白

    2013-01-01

    A method was developed for the determination of trace-amount chlorinated/brominated flame, retardants and their metabolites in breast milk by gas chromatography combined with mass spectrum in negative chemical ionization mode (GC/NCI-LRMS ). Chlorinated/brominated flame retardants and their metabolites were classified into netural and phenolic fractions. Neutral targets included eight brominated diphenyl ether (BDE) congeners (including BDE-209) , five MeO-BDE congeners and other new flame retardants or the metabolites. Phenolic targets referred to nine OH-BDEs congeners. The efficient separation of various neutral targets was obtained on a 30-m column (RTX-1614) and that of phenolic targets was achieved on a 30-m column ( DB-5 ) in the optimized GC condition. In the extraction and clean-up procedures, before supersonic extracting, surrogate/internal standards were required spiking into breast milk, then the samples were separated into neutral and phenolic fractions by a liquid-liquid extraction methods. The extracts were cleaned-up further to remove other co-extracts by sulfuric acid silica prior to injection. It was noticeable that phenolic fractions required to be further derived by diazomethane before clean-up. The recoveries of decabrominated diphenyl ethers, other polybrominated diphenyl ethers, methoxyl-polybrominated diphenyl ethers, dechlorane plus and dechlorinated products, other flame retardants, hydroxylated polybrominated diphenyl ethers were 66.5% -75.4% , 84.2% -126.4% , 60.9% -115.1% , 86.7% -104.9% , 42.9% -113. 8% and 64.7% -129. 5% , respectively. The RSD of neutral targets were all below 22% , and those of the phenolic targets were all below 30%. The method was used for the determination of targets in breast milk collected from an e-waste dismantling area. The results of quality control showed the method was reliable investigation.%建立了低分辨气相色谱-负化学源质谱法(GC/NCI-LRMS)定性与定量检测母乳中的溴代/氯代

  10. Levels of brominated diphenylether, dibenzo-P-dioxin, and dibenzofuran in flue gases of a municipal waste combustor

    Science.gov (United States)

    Due to the extensive use of brominated flame retardants (BFRs), including brominated diphenylether (BDE) formulations, for various domestic and industrial applications, the presence of brominated chemicals in the waste stream is to be expected for decades. As much as 40% to 50% o...

  11. Developmental exposure to a brominated flame retardant: An assessment of effects on physiology, growth, and reproduction in a songbird, the zebra finch

    International Nuclear Information System (INIS)

    Eng, Margaret L.; Williams, Tony D.; Elliott, John E.

    2013-01-01

    Mixtures of polybrominated diphenyl ethers (PBDEs) have been widely used as additive flame retardants, and BDE-99 is one of the most predominant congeners found in the environment. BDE-99 has been reported in avian samples worldwide, yet knowledge of its toxicity to birds is minimal. We assessed the short- and long-term effects of nestling exposure to environmentally relevant levels of BDE-99 in a model passerine, the zebra finch. Early exposure to BDE-99 did not affect hematocrit, oxidative stress, or thyroid hormones in either the juvenile or adult stages, and there were no effects on chick growth or survival. BDE-99 exposure caused a dose-dependent delay in timing of reproduction, but there were no other effects on reproductive success. In zebra finches, endpoints related to reproductive behavior appear to be the most sensitive to BDE-99. However, passerines overall appear to be less sensitive than birds of prey or mammals to PBDE exposure. -- Highlights: •We exposed zebra finches nestlings to BDE-99 and raised them to sexual maturity. •Found no effects on physiology, chick growth, survival, or reproductive success. •As BDE-99 dose increased, laying interval increased. •Passerine birds possibly less sensitive to BDE-99 than mammals or other bird species. -- Nestling exposure to BDE-99 affects timing of breeding in zebra finches, but overall passerines appear to be less sensitive to PBDEs than mammals or other bird species

  12. Preparation of bromine fluoride

    International Nuclear Information System (INIS)

    Domange, Pr; Duflo, J.

    1958-05-01

    This note addresses the preparation of bromine fluoride. It indicates the implemented process for the reaction, used products (fluorine and bromine), and column characteristics. It describes the operating mode. Apparatus drawing is provided

  13. Combining Eosin Y with Selectfluor: A Regioselective Brominating System for Para-Bromination of Aniline Derivatives.

    Science.gov (United States)

    Huang, Binbin; Zhao, Yating; Yang, Chao; Gao, Yuan; Xia, Wujiong

    2017-07-21

    A mild, metal-free, and absolutely para-selective bromination of aniline derivatives has been developed in excellent yields, wherein the organic dye Eosin Y is employed as the bromine source in company with Selectfluor. Neither air nor moisture sensitive, this facile reaction proceeds smoothly at room temperature and completes within a short time. Mechanistic studies indicate a radical pathway; therefore, the existence of an in situ generated brominating reagent, "Selectbrom", is postulated, which may reasonably account for the unique regioselectivity for the para-bromination of N-acyl- as well as N-sulfonylanilines.

  14. Analytical method for biomonitoring of endocrine-disrupting compounds (bisphenol A, parabens, perfluoroalkyl compounds and a brominated flame retardant) in human hair by liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Martín, Julia; Santos, Juan Luis; Aparicio, Irene, E-mail: iaparicio@us.es; Alonso, Esteban

    2016-11-16

    In this paper, a method for the determination of four groups of endocrine-disrupting compounds in human hair is proposed. Target compounds were a plastic monomer (bisphenol A), three parabens commonly used as preservatives (methylparaben, ethylparaben and propylparaben), six perfluoroalkyl compounds commonly used as water, oil and dirt repellents (perfluorooctane sulfonic acid and five perfluoroalkyl carboxylic acids, with alkyl chains from four to eight carbon atoms) and a brominated flame retardant (hexabromocyclododecane). All of them are of especial concern to human health because they are utilized in many everyday products. The method is based on hair incubation with methanol/acetic acid solution (85:15, v/v), extraction with acetone for 15 min in an ultrasonic bath and analysis by liquid chromatography-electrospray-tandem mass spectrometry in negative ionization mode. Limits of quantification in hair samples ranged from 0.6 ng g{sup −1} to 6.1 ng g{sup −1}, except for hexabromocyclododecane (36 ng g{sup −1}). Recoveries were higher than 69%. Intra-day and inter-day precision, expressed as relative standard deviation, were lower than 15% and 10%, respectively. The applicability of the method was proven by analyzing the target compounds in hair samples from six volunteers. High frequencies of detection and concentrations were obtained for bisphenol A (83% of samples; concentrations up to 158 ng g{sup −1}) and parabens (100% of samples; concentrations up to 624 ng g{sup −1}). Lower concentrations were detected for the perfluoroalkyl compounds (up to 13 ng g{sup −1}). Hexabromocyclododecane was not detected. - Highlights: • Method for biomonitoring of endocrine-disrupting compounds in human hair. • Target compounds are commonly present in everyday products. • Method based on hair digestion and liquid chromatography-tandem mass spectrometry. • Good sensitivity, recoveries and precision and low matrix effect were obtained.

  15. Analytical method for biomonitoring of endocrine-disrupting compounds (bisphenol A, parabens, perfluoroalkyl compounds and a brominated flame retardant) in human hair by liquid chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    Martín, Julia; Santos, Juan Luis; Aparicio, Irene; Alonso, Esteban

    2016-01-01

    In this paper, a method for the determination of four groups of endocrine-disrupting compounds in human hair is proposed. Target compounds were a plastic monomer (bisphenol A), three parabens commonly used as preservatives (methylparaben, ethylparaben and propylparaben), six perfluoroalkyl compounds commonly used as water, oil and dirt repellents (perfluorooctane sulfonic acid and five perfluoroalkyl carboxylic acids, with alkyl chains from four to eight carbon atoms) and a brominated flame retardant (hexabromocyclododecane). All of them are of especial concern to human health because they are utilized in many everyday products. The method is based on hair incubation with methanol/acetic acid solution (85:15, v/v), extraction with acetone for 15 min in an ultrasonic bath and analysis by liquid chromatography-electrospray-tandem mass spectrometry in negative ionization mode. Limits of quantification in hair samples ranged from 0.6 ng g"−"1 to 6.1 ng g"−"1, except for hexabromocyclododecane (36 ng g"−"1). Recoveries were higher than 69%. Intra-day and inter-day precision, expressed as relative standard deviation, were lower than 15% and 10%, respectively. The applicability of the method was proven by analyzing the target compounds in hair samples from six volunteers. High frequencies of detection and concentrations were obtained for bisphenol A (83% of samples; concentrations up to 158 ng g"−"1) and parabens (100% of samples; concentrations up to 624 ng g"−"1). Lower concentrations were detected for the perfluoroalkyl compounds (up to 13 ng g"−"1). Hexabromocyclododecane was not detected. - Highlights: • Method for biomonitoring of endocrine-disrupting compounds in human hair. • Target compounds are commonly present in everyday products. • Method based on hair digestion and liquid chromatography-tandem mass spectrometry. • Good sensitivity, recoveries and precision and low matrix effect were obtained. • Method was successfully

  16. Flame treatment for the selective wetting and separation of PVC and PET.

    Science.gov (United States)

    Pascoe, R D; O'Connell, B

    2003-01-01

    Flame treatment has been used for many years to modify the surface of plastics to allow coatings to be added. The effect of the treatment is to produce hydrophilic species on the surface of the plastic making it water-wettable. The production of hydrophilic plastic surfaces is also required in the selective separation of plastics by froth flotation. For the process to be selective one plastic must be rendered hydrophilic while another remains hydrophobic. In this study the potential for separation of PVC and PET has been investigated. Flame treatment was shown to be very effective in producing a hydrophilic surface on both plastics, although the process was not selective under the conditions investigated. Raising the temperature of the plastics above their softening point produced a hydrophobic recovery. As the softening point of PVC was significantly lower than for PET it was possible to produce a significant difference in hydrophobicity, as judged using contact angle measurement. When immersed in water the contact angle of the PVC was found to be strongly dependent on the pH. Good separation efficiency of the two plastics was achieved by froth flotation from pH 4 to 9. One particular advantage of the technique is that no chemical reagents may be required in the flotation stage. The practicalities of designing a flake treatment system however have to be addressed before considering it to be a viable industrial process.

  17. Flame treatment for the selective wetting and separation of PVC and PET

    International Nuclear Information System (INIS)

    Pascoe, R.D.; O'Connell, B.

    2003-01-01

    Flame treatment has been used for many years to modify the surface of plastics to allow coatings to be added. The effect of the treatment is to produce hydrophilic species on the surface of the plastic making it water-wettable. The production of hydrophilic plastic surfaces is also required in the selective separation of plastics by froth flotation. For the process to be selective one plastic must be rendered hydrophilic while another remains hydrophobic. In this study the potential for separation of PVC and PET has been investigated. Flame treatment was shown to be very effective in producing a hydrophilic surface on both plastics, although the process was not selective under the conditions investigated. Raising the temperature of the plastics above their softening point produced a hydrophobic recovery. As the softening point of PVC was significantly lower than for PET it was possible to produce a significant difference in hydrophobicity, as judged using contact angle measurement. When immersed in water the contact angle of the PVC was found to be strongly dependent on the pH. Good separation efficiency of the two plastics was achieved by froth flotation from pH 4 to 9. One particular advantage of the technique is that no chemical reagents may be required in the flotation stage. The practicalities of designing a flake treatment system however have to be addressed before considering it to be a viable industrial process

  18. Selective Oxidation Using Flame Aerosol Synthesized Iron and Vanadium-Doped Nano-TiO2

    Directory of Open Access Journals (Sweden)

    Zhong-Min Wang

    2011-01-01

    Full Text Available Selective photocatalytic oxidation of 1-phenyl ethanol to acetophenone using titanium dioxide (TiO2 raw and doped with Fe or V, prepared by flame aerosol deposition method, was investigated. The effects of metal doping on crystal phase and morphology of the synthesized nanostructured TiO2 were analyzed using XRD, TEM, Raman spectroscopy, and BET nitrogen adsorbed surface area measurement. The increase in the concentration of V and Fe reduced the crystalline structure and the anatase-to-rutile ratios of the synthesized TiO2. Synthesized TiO2 became fine amorphous powder as the Fe and V concentrations were increased to 3 and 5%, respectively. Doping V and Fe to TiO2 synthesized by the flame aerosol increased photocatalytic activity by 6 folds and 2.5 folds, respectively, compared to that of pure TiO2. It was found that an optimal doping concentration for Fe and V were 0.5% and 3%, respectively. The type and concentration of the metal dopants and the method used to add the dopant to the TiO2 are critical parameters for enhancing the activity of the resulting photocatalyst. The effects of solvents on the photocatalytic reaction were also investigated by using both water and acetonitrile as the reaction medium.

  19. Bromine intercalated graphite for lightweight composite conductors

    KAUST Repository

    Amassian, Aram; Patole, Archana

    2017-01-01

    A method of fabricating a bromine-graphite/metal composite includes intercalating bromine within layers of graphite via liquid-phase bromination to create brominated-graphite and consolidating the brominated-graphite with a metal nanopowder via a

  20. Estimation of human percutaneous bioavailability for two novel brominated flame retardants, 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EH-TBB) and bis(2-ethylhexyl) tetrabromophthalate (BEH-TEBP)

    International Nuclear Information System (INIS)

    Knudsen, Gabriel A.; Hughes, Michael F.; Sanders, J. Michael; Hall, Samantha M.; Birnbaum, Linda S.

    2016-01-01

    2-Ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB) and bis(2-ethylhexyl)tetrabromophthalate (BEH-TEBP) are novel brominated flame retardants used in consumer products. A parallelogram approach was used to predict human dermal absorption and flux for EH-TBB and BEH-TEBP. [ 14 C]-EH-TBB or [ 14 C]-BEH-TEBP was applied to human or rat skin at 100 nmol/cm 2 using a flow-through system. Intact rats received analogous dermal doses. Treated skin was washed and tape-stripped to remove “unabsorbed” [ 14 C]-radioactivity after continuous exposure (24 h). “Absorbed” was quantified using dermally retained [ 14 C]-radioactivity; “penetrated” was calculated based on [ 14 C]-radioactivity in media (in vitro) or excreta + tissues (in vivo). Human skin absorbed EH-TBB (24 ± 1%) while 0.2 ± 0.1% penetrated skin. Rat skin absorbed more (51 ± 10%) and was more permeable (2 ± 0.5%) to EH-TBB in vitro; maximal EH-TBB flux was 11 ± 7 and 102 ± 24 pmol-eq/cm 2 /h for human and rat skin, respectively. In vivo, 27 ± 5% was absorbed and 13% reached systemic circulation after 24 h (maximum flux was 464 ± 65 pmol-eq/cm 2 /h). BEH-TEBP in vitro penetrance was minimal (< 0.01%) for rat or human skin. BEH-TEBP absorption was 12 ± 11% for human skin and 41 ± 3% for rat skin. In vivo, total absorption was 27 ± 9%; 1.2% reached systemic circulation. In vitro maximal BEH-TEBP flux was 0.3 ± 0.2 and 1 ± 0.3 pmol-eq/cm 2 /h for human and rat skin; in vivo maximum flux for rat skin was 16 ± 7 pmol-eq/cm 2 /h. EH-TBB was metabolized in rat and human skin to tetrabromobenzoic acid. BEH-TEBP-derived [ 14 C]-radioactivity in the perfusion media could not be characterized. < 1% of the dose of EH-TBB and BEH-TEHP is estimated to reach the systemic circulation following human dermal exposure under the conditions tested. Chemical compounds studied in this article: 2-Ethylhexyl 2,3,4,5-tetrabromobenzoate (PubChem CID: 71316600; CAS No. 183658-27-7 FW: 549.92 g/mol logP est : 7.73–8

  1. Estimation of human percutaneous bioavailability for two novel brominated flame retardants, 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EH-TBB) and bis(2-ethylhexyl) tetrabromophthalate (BEH-TEBP)

    Energy Technology Data Exchange (ETDEWEB)

    Knudsen, Gabriel A., E-mail: gabriel.knudsen@nih.gov [NCI Laboratory of Toxicology and Toxicokinetics, 111 T W Alexander Dr., Research Triangle Park, NC (United States); Hughes, Michael F. [Integrated Systems Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Sanders, J. Michael; Hall, Samantha M.; Birnbaum, Linda S. [NCI Laboratory of Toxicology and Toxicokinetics, 111 T W Alexander Dr., Research Triangle Park, NC (United States)

    2016-11-15

    2-Ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB) and bis(2-ethylhexyl)tetrabromophthalate (BEH-TEBP) are novel brominated flame retardants used in consumer products. A parallelogram approach was used to predict human dermal absorption and flux for EH-TBB and BEH-TEBP. [{sup 14}C]-EH-TBB or [{sup 14}C]-BEH-TEBP was applied to human or rat skin at 100 nmol/cm{sup 2} using a flow-through system. Intact rats received analogous dermal doses. Treated skin was washed and tape-stripped to remove “unabsorbed” [{sup 14}C]-radioactivity after continuous exposure (24 h). “Absorbed” was quantified using dermally retained [{sup 14}C]-radioactivity; “penetrated” was calculated based on [{sup 14}C]-radioactivity in media (in vitro) or excreta + tissues (in vivo). Human skin absorbed EH-TBB (24 ± 1%) while 0.2 ± 0.1% penetrated skin. Rat skin absorbed more (51 ± 10%) and was more permeable (2 ± 0.5%) to EH-TBB in vitro; maximal EH-TBB flux was 11 ± 7 and 102 ± 24 pmol-eq/cm{sup 2}/h for human and rat skin, respectively. In vivo, 27 ± 5% was absorbed and 13% reached systemic circulation after 24 h (maximum flux was 464 ± 65 pmol-eq/cm{sup 2}/h). BEH-TEBP in vitro penetrance was minimal (< 0.01%) for rat or human skin. BEH-TEBP absorption was 12 ± 11% for human skin and 41 ± 3% for rat skin. In vivo, total absorption was 27 ± 9%; 1.2% reached systemic circulation. In vitro maximal BEH-TEBP flux was 0.3 ± 0.2 and 1 ± 0.3 pmol-eq/cm{sup 2}/h for human and rat skin; in vivo maximum flux for rat skin was 16 ± 7 pmol-eq/cm{sup 2}/h. EH-TBB was metabolized in rat and human skin to tetrabromobenzoic acid. BEH-TEBP-derived [{sup 14}C]-radioactivity in the perfusion media could not be characterized. < 1% of the dose of EH-TBB and BEH-TEHP is estimated to reach the systemic circulation following human dermal exposure under the conditions tested. Chemical compounds studied in this article: 2-Ethylhexyl 2,3,4,5-tetrabromobenzoate (PubChem CID: 71316600; CAS No. 183658

  2. Occurrence of bromine in fluidised bed combustion of solid recovered fuel

    Energy Technology Data Exchange (ETDEWEB)

    Vainikka, P.

    2011-12-15

    Corrosive ash species are the single most important factor limiting the electric efficiency of steam boiler plants fired with waste or biomass. Chlorine has been found to have a central role in the chemistry involved as it reduces the melting temperature of ash, forms corrosive vapour and gas species in the furnace and halogenated deposits on boiler heat transfer surfaces. In this context chlorine has been extensively researched. At the time of writing this thesis there was hardly any published data available on the occurrence of bromine (Br) in the aforementioned context. The objective of this work was to review the occurrence of bromine in solid fuels and characterise the behaviour of bromine in full-scale fluidised bed combustion. The review on the occurrence of bromine in solid fuels revealed that in anthropogenic wastes bromine is mainly found in connection to flame retarded substances. Several weight percentages of bromine can be found in plastics treated with brominated flame retardants (BFRs). Bromine is typically found some 100-200 mg kg-1 in mixed municipal solid wastes (MSW). Bromine may be enriched in fuels with high share of plastics, such as solid recovered fuel (SRF) or refuse derived fuel (RDF). Up to 2000 mg kg-1 was found as a monthly average in SRF, typical levels being 20-200 mg kg-1. Wastewater sludge from paper mills may contain bromine 20-100 mg kg-1 due the use of bromine based biocides. In other fuels bromine may be found in significant amounts in marine influenced coal deposits and peat as well as in biomass treated with brominated pesticides. In the experimental part SRF, spruce bark and wastewater sludge from a paper mill were co-fired in a full- scale bubbling fluidised bed (BFB) boiler, and the collected fuels, aerosols and waterwall deposits were analysed with the focus on the fate of bromine. Bromine was mainly found to form water soluble high vapour pressure alkali metal halides in the furnace - in the form of KBr(g) and NaBr(g) as

  3. Peroxometal-mediated oxidation of bromine leading to ...

    Indian Academy of Sciences (India)

    Administrator

    Peroxometal-mediated oxidation of bromine leading to environmentally favourable protocol for selective bromination of organic substrates: Implications for vanadium bromo peroxidase (VBrPO). SIDDHARTHA D DHAR and MIHIR K CHAUDHURI. Department of Chemistry, Indian Institute of Technology,. Guwahati 781 001 ...

  4. Domestic Preparedness Program: Evaluation of the Agilent Gas Chromatograph - Flame Photometric Detector/Mass Selective Detector (GC-FPD/MSD) System Against Chemical Warfare Agents Summary Report

    National Research Council Canada - National Science Library

    Longworth, Terri

    2003-01-01

    This report characterizes the chemical warfare agent (CWA) detection potential of the commercially available Agilent gas chromatograph-flame photometric detector/mass selective detector (GC-FPD/MSD...

  5. Bromine intercalated graphite for lightweight composite conductors

    KAUST Repository

    Amassian, Aram

    2017-07-20

    A method of fabricating a bromine-graphite/metal composite includes intercalating bromine within layers of graphite via liquid-phase bromination to create brominated-graphite and consolidating the brominated-graphite with a metal nanopowder via a mechanical pressing operation to generate a bromine-graphite/metal composite material.

  6. Life cycle assessment of flame retardants in an electronics application

    NARCIS (Netherlands)

    Jonkers, Niels; Krop, Hildo; van Ewijk, Harry; Leonards, Pim E.G.

    2016-01-01

    Purpose: Flame retardants are added to plastics and textiles to save lives. However, certain brominated flame retardants (BFRs) form an environmental hazard and should be replaced by less harmful alternatives. In the recently completed European research project ENFIRO, we examined which alternatives

  7. Selective detection of isomers with photoionization mass spectrometry for studies of hydrocarbon flame chemistry

    International Nuclear Information System (INIS)

    Cool, Terrill A.; Nakajima, Koichi; Mostefaoui, Toufik A.; Qi, Fei; McIlroy, Andrew; Westmoreland, Phillip R.; Law, Matthew E.; Poisson, Lionel; Peterka, Darcy S.; Ahmed, Musahid

    2003-01-01

    We report the first use of synchrotron radiation, continuously tunable from 8 to 15 eV, for flame-sampling photoionization mass spectrometry (PIMS). Synchrotron radiation offers important advantages over the use of pulsed vacuum ultraviolet lasers for PIMS; these include superior signal-to-noise, soft ionization, and access to photon energies outside the limited tuning ranges of current VUV laser sources. Near-threshold photoionization efficiency measurements were used to determine the absolute concentrations of the allene and propyne isomers of C 3 H 4 in low-pressure laminar ethylene-oxygen and benzene-oxygen flames. Similar measurements of the isomeric composition of C 2 H 4 O species in a fuel-rich ethylene-oxygen flame revealed the presence of substantial concentrations of ethenol (vinyl alcohol) and acetaldehyde. Ethenol has not been previously detected in hydrocarbon flames. Absolute photoionization cross sections were measured for ethylene, allene, propyne, and acetaldehyde, using propene as a calibration standard. PIE curves are presented for several additional reaction intermediates prominent in hydrocarbon flames

  8. Exposure assessment of French women and their newborn to brominated flame retardants: Determination of tri- to deca- polybromodiphenylethers (PBDE) in maternal adipose tissue, serum, breast milk and cord serum

    International Nuclear Information System (INIS)

    Antignac, Jean-Philippe; Cariou, Ronan; Zalko, Daniel; Berrebi, Alain; Cravedi, Jean-Pierre; Maume, Daniel; Marchand, Philippe; Monteau, Fabrice; Riu, Anne; Andre, Francois; Le Bizec, Bruno

    2009-01-01

    In the frame of a French monitoring program, tri- to deca- polybromodiphenylethers (PBDE) have been measured in maternal and cord serum, adipose tissue, and breast milk samples, collected from 93 volunteer women during caesarean deliveries. The seven major tri- to heptaBDE (BDE-28, 47, 99, 100, 153, 154, and 183) were detected in adipose tissue and breast milk with cumulated median values of 2.59 and 2.51 ng g -1 l w. Nine highly brominated octa- to decaBDE (BDE-196, 197, 201, 202, 203, 206, 207, 208 and 209) was performed in the same samples, with cumulated median values of 2.73 and 3.39 ng g -1 l w in adipose tissue and breast milk, respectively. At this opposite, median levels of octa- to decaBDE in maternal and cord serum appeared significantly higher than the levels of tri- to heptaBDE in the same matrices, i.e. 8.85 and 12.34 versus 0.98 and 0.69 ng g -1 l w, respectively. - This study provides the first data at the French level regarding the occurrence of PBDE in human, and demonstrates the exposure of both human foetus at late stage of pregnancy and newborn at early stages of life through breastfeeding with special emphasis on the presence of highly brominated compounds

  9. Exposure assessment of French women and their newborn to brominated flame retardants: Determination of tri- to deca- polybromodiphenylethers (PBDE) in maternal adipose tissue, serum, breast milk and cord serum

    Energy Technology Data Exchange (ETDEWEB)

    Antignac, Jean-Philippe [Laboratoire d' Etude des Residus et Contaminants dans les Aliments (LABERCA), USC INRA 2013, Ecole Nationale Veterinaire de Nantes (ENVN), Route de Gachet, BP 50707, 44307 Nantes Cedex 3 (France)], E-mail: antignac@vet-nantes.fr; Cariou, Ronan [Laboratoire d' Etude des Residus et Contaminants dans les Aliments (LABERCA), USC INRA 2013, Ecole Nationale Veterinaire de Nantes (ENVN), Route de Gachet, BP 50707, 44307 Nantes Cedex 3 (France); Zalko, Daniel [UMR 1089 Xenobiotiques, INRA, 31931 Toulouse (France); Berrebi, Alain [Centre Hospitalier Universitaire de Toulouse, Hopital Paule de Viguier, Service de gynecologie-obstetrique, Toulouse (France); Cravedi, Jean-Pierre [UMR 1089 Xenobiotiques, INRA, 31931 Toulouse (France); Maume, Daniel; Marchand, Philippe; Monteau, Fabrice [Laboratoire d' Etude des Residus et Contaminants dans les Aliments (LABERCA), USC INRA 2013, Ecole Nationale Veterinaire de Nantes (ENVN), Route de Gachet, BP 50707, 44307 Nantes Cedex 3 (France); Riu, Anne [Unite Signalisation Hormonale, Environnement et Cancer, U824 INSERM, 34298 Montpellier Cedex 5 (France); Andre, Francois; Le Bizec, Bruno [Laboratoire d' Etude des Residus et Contaminants dans les Aliments (LABERCA), USC INRA 2013, Ecole Nationale Veterinaire de Nantes (ENVN), Route de Gachet, BP 50707, 44307 Nantes Cedex 3 (France)

    2009-01-15

    In the frame of a French monitoring program, tri- to deca- polybromodiphenylethers (PBDE) have been measured in maternal and cord serum, adipose tissue, and breast milk samples, collected from 93 volunteer women during caesarean deliveries. The seven major tri- to heptaBDE (BDE-28, 47, 99, 100, 153, 154, and 183) were detected in adipose tissue and breast milk with cumulated median values of 2.59 and 2.51 ng g{sup -1} l w. Nine highly brominated octa- to decaBDE (BDE-196, 197, 201, 202, 203, 206, 207, 208 and 209) was performed in the same samples, with cumulated median values of 2.73 and 3.39 ng g{sup -1} l w in adipose tissue and breast milk, respectively. At this opposite, median levels of octa- to decaBDE in maternal and cord serum appeared significantly higher than the levels of tri- to heptaBDE in the same matrices, i.e. 8.85 and 12.34 versus 0.98 and 0.69 ng g{sup -1} l w, respectively. - This study provides the first data at the French level regarding the occurrence of PBDE in human, and demonstrates the exposure of both human foetus at late stage of pregnancy and newborn at early stages of life through breastfeeding with special emphasis on the presence of highly brominated compounds.

  10. Determination of bromine in selected polymer materials by a wavelength-dispersive X-ray fluorescence spectrometric method - Critical thickness problem and solutions

    Science.gov (United States)

    Gorewoda, Tadeusz; Mzyk, Zofia; Anyszkiewicz, Jacek; Charasińska, Jadwiga

    2015-04-01

    The purpose of this study was to develop an accurate method for the determination of bromine in polymer materials using X-ray fluorescence spectrometry when the thickness of the sample is less than the bromine critical thickness (tc) value. This is particularly important for analyzing compliance with the Restriction of Hazardous Substances Directive. Mathematically and experimentally estimated tc values in polyethylene and cellulose matrixes were up to several millimeters. Four methods were developed to obtain an accurate result. These methods include the addition of an element with a high mass absorption coefficient, the measurement of the total bromine contained in a defined volume of the sample, the exploitation of tube-Rayleigh line intensities and using the Br-Lβ line.

  11. Synthesis of substituted bromobenzene derivatives via bromoanilines. A moderately selective ortho-bromination of [14C]-aniline

    International Nuclear Information System (INIS)

    Weller, P.E.; Hanzlik, R.P.

    1988-01-01

    The synthesis of [ 14 C]-labeled bromobenzene, 2-bromophenol, 4-bromophenol, 1,2-dibromobenzene, 2-bromobenzonitrile, 2-bromotoluene, and 2-bromoanisole are reported. [ 14 C]-Aniline is selectively monobrominated to ortho- and para-bromoanilines in 5 to 3 ratio. The separated bromoanilines are diazotized and either reduced, hydrolyzed, coupled to bromide, coupled to cyanide, or coupled to carbon. 2-Bromophenol is O-methylated to 2-bromoanisole. (author)

  12. Selective bromination of 4-chloro-1-indanone and synthesis of (4-chloro-2, 3-dihydro-1H-indene-2-yl)methanamine

    OpenAIRE

    Jasouri, S.; Khalafy, J.; Badali, M.; Piltan, M.

    2010-01-01

    The synthesis of 4-chloro-1-indanone in four steps from 2-chlorobenzaldehyde was investigated. Bromination of this compound under various conditions occurred in the cyclopentanone ring, producing mono- and dibromo derivatives. Cyanation of 2-bromo-4-chloro-1-indanone followed by reduction gave (4-chloro-2, 3-dihydro-1H-indene-2-yl)methanamine in quantitative yield.

  13. Atmospheric Bromine in the Arctic

    International Nuclear Information System (INIS)

    Berg, W.W.; Sperry, P.D.; Rahn, K.A.; Gladney, E.S.

    1983-01-01

    We report the first measurements of both particulate and gas phase bromine in the Arctic troposphere. Data from continuous sampling of the Arctic aerosol over a period of 4 years (1976--1980) indicate that the bromine content in the aerosol averages 6 +- 4 ngBr/SCM (5 +- 3 pptm Br) for 9 months of every year. During the 3-month period between February 15 and May 15, however, we observed an annual sharp maximum in particulate bromine with levels exceeding 100 ngBr/SCM (82 pptm Br). The Arctic aerosol showed no bromine enrichment relative to seawater except for this 3 month peak period. During the bromine maximum, enrichment factors reached 40 with average values near 10. Calculations of the amount of excess bromine in the Arctic aerosol showed that over 90% of the peak bromine had an origin other than from direct bulk seawater injection. Total levels of gas phase bromine in the Arctic troposphere found during the peak aerosol period averaged 422 +- 48 ngBr/SCM (118 +- 14 pptv). Total bromine content during this period averaged 474 +- 49 ngBr/SCM with gas-to-particle ratios ranging from 7 to 18. A measurement under nonpeak conditions showed total bromine levels at <25 ngBr/SCM. The possibility that local contamination contributed to the seasonal development of the 3-month bromine peak was carefully considered and ruled out. Elevated particualte bromine levels, with peak values ranging from 22 to 30 ngBr/SCM, were also found at Ny-Alesund, Spitsbergen (Norway). The apparent seasonal nature of this bromine peak suggests that the large bromine maximum observed at Barrow is not an isolated or unique phenomenon characteristic of that sampling location

  14. Brominated flame retardants as persistent organic pollutants. Distribution in the environment and human exposition; Los retardantes de llama bromados como compuestos organicos persistentes. Distribucion en el medio ambiente y exposicion en humanos

    Energy Technology Data Exchange (ETDEWEB)

    Fabrellas, B.; Solis, A.; Alvarez, A.; Larrazabal, D.; Martinez, A.

    2004-07-01

    Polybrominated diphenyl ethers (PBDE) are a family of synthetic chemicals widely used in industry to delay, inhibit or even suppress combustion process in manufactured items. Flame retardant products are frequently added into plastic, electronic, paint and textile materials to reduce the risk of ignition. During last years, increasing levels of PBDEs have been detected in the environment, suggesting release from the treated surface as main pathway for environmental intake. Their physicochemical structure makes them substances of highly lipophilic bio accumulative and persistent nature, with potential toxic effects observed onto wildlife and humans. This publication resumes actual knowledge on PBDEs research and submits initiatives of human and environment exposure minimization. (Author)

  15. (Development of Bromine-77 from the LAMPF facility)

    Energy Technology Data Exchange (ETDEWEB)

    1989-01-01

    The objective of the work was to conduct the necessary studies required to evaluate the efficacy, potential benefit and role of bromine-77 labeled steroids in the detection and evaluation of treatment for hormone-dependent tumors. This report presents progress on the following tasks: An initial investigation concentrating on the radiobromination at carbon-6 or carbon-7 in selected simple steroids utilizing the nuclides, bromine-82 and bromine-77, analytical spectroscopy of radiolabeled compounds, and investigating the biodistribution, toxicology and tumor affinity of labeled agents.

  16. Selectivity Enhancement by Using Double-Layer MOX-Based Gas Sensors Prepared by Flame Spray Pyrolysis (FSP

    Directory of Open Access Journals (Sweden)

    Julia Rebholz

    2016-09-01

    Full Text Available Here we present a novel concept for the selective recognition of different target gases with a multilayer semiconducting metal oxide (SMOX-based sensor device. Direct current (DC electrical resistance measurements were performed during exposure to CO and ethanol as single gases and mixtures of highly porous metal oxide double- and single-layer sensors obtained by flame spray pyrolysis. The results show that the calculated resistance ratios of the single- and double-layer sensors are a good indicator for the presence of specific gases in the atmosphere, and can constitute some building blocks for the development of chemical logic devices. Due to the inherent lack of selectivity of SMOX-based gas sensors, such devices could be especially relevant for domestic applications.

  17. Formation of brominated pollutants during the pyrolysis and combustion of tetrabromobisphenol A at different temperatures

    International Nuclear Information System (INIS)

    Ortuño, Nuria; Moltó, Julia; Conesa, Juan A.; Font, Rafael

    2014-01-01

    Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant worldwide. A detailed examination of the degradation products emitted during thermal decomposition of TBBPA is presented in the study. Runs were performed in a laboratory furnace at different temperatures (650 and 800 °C) and in different atmospheres (nitrogen and air). More than one hundred semivolatile compounds have been identified by GC/MS, with special interest in brominated ones. Presence of HBr and brominated light hydrocarbons increased with temperature and in the presence of oxygen. Maximum formation of PAHs is observed at pyrolytic condition at the higher temperature. High levels of 2,4-, 2,6- and 2,4,6- bromophenols were found. The levels of polybrominated dibenzo-p-dioxins and furans have been detected in the ppm range. The most abundant isomers are 2,4,6,8-TeBDF in pyrolysis and 1,2,3,7,8-PeBDF in combustion. These results should be considered in the assessment of thermal treatment of materials containing brominated flame retardants. - Highlights: • Decomposition of a brominated flame retardant is performed in a laboratory furnace. • Both pyrolysis and combustion at two different temperatures are studied. • Brominated organic compounds such as Br-dioxins and furans are analysed. • Main product of decomposition is HBr, accounting for ca. 50%. • Very high and dangerous levels of PBDD/Fs and precursors (bromophenols) are detected. - TBBPA mainly decomposes to give HBr and brominated hydrocarbons at high temperature, but high levels of bromophenols and polybrominated dibenzo-p-dioxins and furans are also produced

  18. Uranium hexafluoride. Bromine spectrophotometric determination

    International Nuclear Information System (INIS)

    Anon.

    Bromine determination in hydrolized uranium hexafluoride by reduction of bromates by ferrous sulfate, oxidation of bromides by potassium permanganate to give bromine which is extracted into carbon tetrachloride and transformed in eosine for spectrophotometry at 510 nm. The method is suitable for determining 5 to 150 ppm with respect to uranium [fr

  19. Brominated Dioxins: Little-Known New Health Hazards - A Review

    Directory of Open Access Journals (Sweden)

    Piskorska-Pliszczyńska Jadwiga

    2014-10-01

    Full Text Available This article reviews the present state of the science concerning the polybrominated dibenzo-p-dioxins (PBDDs and dibenzofurans (PBDFs. Everywhere in the world people are exposed to anthropogenic origin chemicals. Some of them are long-lived organic compounds, which persist over the years in the environment. Persistent organic pollutants, such as organohalogen compounds, accumulate in environmental and biological compartments and have adverse effects on the health of humans and animals. Little is known about the brominated and mixed chloro/bromo dioxin and furans. Existing literature suggests that brominated dioxins and furans have similar toxicity profiles to their chlorinated analogues. The exposure data are extremely limited, showing a major data gap in estimating the potential environmental and health risk of these chemicals. The rapid increase in the use of brominated flame retardants (the main source of these pollutants has raised the level of concern over environmental and health damage from brominated dioxins and furans. It is likely that human as well as wildlife exposure to these contaminants will increase with their greater use. The findings reported here present strong evidence of the PBDDs and PBDFs as an emerging new class of contaminants.

  20. Brominated flame retardant trends in aquatic birds from the Salish Sea region of the west coast of North America, including a mini-review of recent trends in marine and estuarine birds

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Aroha [Department of Applied Biology, University of British Columbia, 2357 Main Mall, Vancouver, BC (Canada); Elliott, John E., E-mail: John.Elliott@ec.gc.ca [Science and Technology, Environment Canada, Delta, BC V4K 3N2 (Canada); Elliott, Kyle H.; Guigueno, Mélanie F. [Department of Biology, University of Western Ontario, 1151 Richmond Street, London, ON N6A 3K7 (Canada); Wilson, Laurie K. [Canadian Wildlife Service, Pacific Wildlife Research Centre, Environment Canada, Delta, BC V4K 3N2 (Canada); Lee, Sandi [Science and Technology, Environment Canada, Delta, BC V4K 3N2 (Canada); Idrissi, Abde [Environment Canada, National Wildlife Research Centre, Ottawa, ON K1A 0H3 (Canada)

    2015-01-01

    Polybrominated diphenyl ethers (PBDEs) increased in many matrices during the 1990s and early 2000s. Since voluntary restrictions and regulations on PBDEs were implemented in North America circa early 2000s, decreases in PBDEs have occurred in many of these same matrices. To examine temporal trends in the North Pacific, we retrospectively analysed PBDEs and eight non-PBDE flame retardants (FR) in eggs of two aquatic bird species, great blue herons, Ardea herodias, and double-crested cormorants, Phalacrocorax auritus, collected along the British Columbia coast, Canada from 1979 to 2012. Increasing PBDE concentrations were observed in both species followed by significant decreases post-2000 for all dominant congeners and ΣPBDE. Non-PBDE FRs were generally undetected in cormorant eggs, or detected at very low levels in heron eggs, except for hexabromocyclododecane (HBCDD). HBCDD, currently unregulated in North America, was not detected in early sampling years; however low concentrations were observed in both species in recent sampling years (2003–2012). Dietary tracers (δ{sup 13}C and δ{sup 15}N) did not change significantly over time, indicating that temporal changes in PBDEs are likely caused by implemented regulations. A comparison with recently published temporal trends of ΣPBDE in marine birds from North America and Europe is given. - Highlights: • Seabird eggs have been used to monitor POPs on the west coast of Canada since 1979. • Samples of these eggs were analysed retrospectively for PBDEs and HBCDD. • Regulations exist in North America to control PBDEs, but not HBCDD. • PBDEs decreased significantly since regulations were applied. • HBCDD was not detected pre-2003, but is now found in low concentrations.

  1. Five-year trends of selected halogenated flame retardants in the atmosphere of Northeast China

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wen-Long; Liu, Li-Yan; Song, Wei-Wei; Zhang, Zi-Feng; Qiao, Li-Na [International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Ma, Wan-Li, E-mail: mawanli002@163.com [International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Li, Yi-Fan, E-mail: ijrc_pts_paper@yahoo.com [International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); IJRC-PTS-NA, Toronto M2N 6X9 (Canada)

    2016-01-01

    This study collected 227 pairs of gas phase and particle phase air samples in a typical urban city of Northeast China from 2008 to 2013. Four alternative halogenated flame retardants for polybrominated diphenyl ethers (PBDEs) were analyzed, namely 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EHTBB), bis (2-ethylhexyl) tetrabromophthalate (BEHTBP), syn-dechlorane plus (syn-DP) and anti-dechlorane plus (anti-DP). The average concentrations for EHTBB and BEHTBP were 5.2 ± 20 and 30 ± 200 pg/m{sup 3}, respectively, while for syn-DP and anti-DP were 1.9 ± 5.1 and 5.8 ± 18 pg/m{sup 3}, respectively. Generally, they were frequently detected in the particle phase, and the gas/particle partitioning suggested they were the maximum partition chemicals. The fractional abundance of EHTBB (f{sub EHTBB}) and syn-DP (f{sub syn}) were comparable with those in other studies. Strong local sources were identified based on the air parcel backward trajectories and the potential source contribution function. The concentrations of these chemicals were significantly increased during this sampling campaign, possibly suggesting their increasing usages from 2008 to 2013 in China. - Highlights: • Five-year air samples were analyzed for four alternative HFRs. • BEHTBP and DP were frequently detected in the particle phase. • Local and nearby city sources of these HFRs were suggested. • Concentrations of these HFRs were significantly increased in the five-year period.

  2. Flame Retardancy of Chemically Modified Lignin as Functional Additive to Epoxy Nanocomposites

    Science.gov (United States)

    John A. Howarter; Gamini P. Mendis; Alex N. Bruce; Jeffrey P. Youngblood; Mark A. Dietenberger; Laura Hasburgh

    2015-01-01

    Epoxy printed circuit boards are used in a variety of electronics applications as rigid, thermally stable substrates. Due to the propensity of components on the boards, such as batteries and interconnects, to fail and ignite the epoxy, flame retardant additives are required to minimize fire risk. Currently, industry uses brominated flame retardants, such as TBBPA, to...

  3. Halogenated flame retardants in the Great Lakes environment.

    Science.gov (United States)

    Venier, Marta; Salamova, Amina; Hites, Ronald A

    2015-07-21

    Flame retardants are widely used industrial chemicals that are added to polymers, such as polyurethane foam, to prevent them from rapidly burning if exposed to a small flame or a smoldering cigarette. Flame retardants, especially brominated flame retardants, are added to many polymeric products at percent levels and are present in most upholstered furniture and mattresses. Most of these chemicals are so-called "additive" flame retardants and are not chemically bound to the polymer; thus, they migrate from the polymeric materials into the environment and into people. As a result, some of these chemicals have become widespread pollutants, which is a concern given their possible adverse health effects. Perhaps because of their environmental ubiquity, the most heavily used group of brominated flame retardants, the polybrominated diphenyl ethers (PBDEs), was withdrawn from production and use during the 2004-2013 period. This led to an increasing demand for other flame retardants, including other brominated aromatics and organophosphate esters. Although little is known about the use or production volumes of these newer flame retardants, it is evident that some of these chemicals are also becoming pervasive in the environment and in humans. In this Account, we describe our research on the occurrence of halogenated and organophosphate flame retardants in the environment, with a specific focus on the Great Lakes region. This Account starts with a short introduction to the first generation of brominated flame retardants, the polybrominated biphenyls, and then presents our measurements of their replacement, the PBDEs. We summarize our data on PBDE levels in babies, bald eagles, and in air. Once these compounds came off the market, we began to measure several of the newer flame retardants in air collected on the shores of the Great Lakes once every 12 days. These new measurements focus on a tetrabrominated benzoate, a tetrabrominated phthalate, a hexabrominated diphenoxyethane

  4. Presence and select determinants of organophosphate flame retardants in public swimming pools

    Energy Technology Data Exchange (ETDEWEB)

    Teo, Tiffany L.L., E-mail: tiffany.teo@unsw.edu.au [UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Kensington NSW 2052 (Australia); Coleman, Heather M., E-mail: h.coleman@ulster.ac.uk [Nanotechnology and Integrated BioEngineering Centre, School of Engineering, University of Ulster, Jordanstown, County Antrim BT37 0QB, Northern Ireland (United Kingdom); Khan, Stuart J., E-mail: s.khan@unsw.edu.au [UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Kensington NSW 2052 (Australia)

    2016-11-01

    The occurrence of five organophosphate flame retardants (PFRs) consisting of tributyl phosphate (TNBP), tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCIPP), tris(1.3-dichloro-2-propyl) phosphate (TDCIPP) and triphenyl phosphate (TPHP) in swimming pools were investigated. Fifteen chlorinated public swimming pools were sampled, including indoor pools, outdoor pools and spa pools. The analyses were carried out using isotope dilution gas chromatography tandem mass spectrometry. All five PFRs were detected in swimming pool waters with concentrations ranging from 5–27 ng/L (TNBP), 7–293 ng/L (TCEP), 62–1180 ng/L (TCIPP), 10–670 ng/L (TDCIPP) and 8–132 ng/L (TPHP). The concentrations of PFRs were generally higher in indoor swimming pools compared to outdoor swimming pools. In municipal water supplies, used to fill the swimming pools in three of the sampling locations, the five PFRs were all below the limit of quantifications, eliminating this as the source. Potential leaching of PFRs from commonly used swimming equipment, including newly purchased kickboards and swimsuits was investigated. These experiments revealed that PFRs leached from swimsuits, and may be a source of PFRs in swimming pools. A quantitative risk assessment revealed that the health risk to PFRs via swimming pools was generally low and below commonly applied health risk benchmarks. - Highlights: • TNBP, TCEP, TCIPP, TDCIPP and TPHP were detected in chlorinated swimming pools. • PFRs were below the LOQ in fill water samples collected from 3 locations. • TCIPP was observed to have the highest concentrations in swimming pools. • PFRs are leaching from swimsuits and may be a source in swimming pools. • Health risks through oral and dermal exposure to PFRs in swimming pools were low.

  5. Presence and select determinants of organophosphate flame retardants in public swimming pools

    International Nuclear Information System (INIS)

    Teo, Tiffany L.L.; Coleman, Heather M.; Khan, Stuart J.

    2016-01-01

    The occurrence of five organophosphate flame retardants (PFRs) consisting of tributyl phosphate (TNBP), tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCIPP), tris(1.3-dichloro-2-propyl) phosphate (TDCIPP) and triphenyl phosphate (TPHP) in swimming pools were investigated. Fifteen chlorinated public swimming pools were sampled, including indoor pools, outdoor pools and spa pools. The analyses were carried out using isotope dilution gas chromatography tandem mass spectrometry. All five PFRs were detected in swimming pool waters with concentrations ranging from 5–27 ng/L (TNBP), 7–293 ng/L (TCEP), 62–1180 ng/L (TCIPP), 10–670 ng/L (TDCIPP) and 8–132 ng/L (TPHP). The concentrations of PFRs were generally higher in indoor swimming pools compared to outdoor swimming pools. In municipal water supplies, used to fill the swimming pools in three of the sampling locations, the five PFRs were all below the limit of quantifications, eliminating this as the source. Potential leaching of PFRs from commonly used swimming equipment, including newly purchased kickboards and swimsuits was investigated. These experiments revealed that PFRs leached from swimsuits, and may be a source of PFRs in swimming pools. A quantitative risk assessment revealed that the health risk to PFRs via swimming pools was generally low and below commonly applied health risk benchmarks. - Highlights: • TNBP, TCEP, TCIPP, TDCIPP and TPHP were detected in chlorinated swimming pools. • PFRs were below the LOQ in fill water samples collected from 3 locations. • TCIPP was observed to have the highest concentrations in swimming pools. • PFRs are leaching from swimsuits and may be a source in swimming pools. • Health risks through oral and dermal exposure to PFRs in swimming pools were low.

  6. The Levels and Analytical Developments of Brominated Flame Retardant Hexabromocyclododecanes from Various Environmental Media%环境中溴系阻燃剂六溴环十二烷的水平及分析进展

    Institute of Scientific and Technical Information of China (English)

    焦杏春; 路国慧; 王晓春; 杨永亮

    2012-01-01

    Hexabromocyclododecanes (HBCDs) are used as flame retardants primarily in thermal insulation building materials, upholstery textiles, and a little in electronics. During 2006, the production and use of penta- and octa-bromodiphenyl ethers was restricted in Europe, and therefore HBCDs may be used as an alternative for polybrominated diphenyl ethers (PBDEs) in some applications. The atmosphere and bodies of water are the two main persistent reservoirs. The high content of HBCDs was detected in the environmental medium adjacent to the point source, which was much higher than that in the region without any point source. According to the different compound structure, environmental condition and biological metabolism processing, synthetic HBCDs were mainly y-HBCD and the biotic HBCDs were a-HBCD. Although the Gas Chromatography-Mass Spectrometry (GC-MS) technique has high sensitive detection for HBCDs, it is restricted to isomer analysis of compounds by thermal recomposition and thermal degradation of HBCDs. LC-MS overcame these restrictions and was applied to distinguish enantiomer anddiastereomer. The detection limit was improved by the coupling technique of MS/MS. This review summarizes the levels and analytical developments of HBCDs. HBCD stereoisomers transform and degrade during production, which is a potential avenue for future research work. Further study on the environmental behaviour of HBCDs, their evolvement trend, control measures and alternative development are suggested in order to to build a larger HBCD database to meet the convention and to prepare more efficient risk management.%六溴环十二烷(HBCDs)是一种添加型溴系阻燃剂,被广泛应用于建筑隔热材料、纺织用品及少量电子产品中.2006年欧盟、国际公约等组织相继停止生产和使用多溴联苯醚后,HBCDs也曾在某些用途中作为替代品使用.在各环境介质中,空气和水体是HBCDs的主要释放空间.点源附近的环境介质中通常能够

  7. Radiation flame proofing of polyester/cotton blends

    International Nuclear Information System (INIS)

    Liepins, R.; Surles, J.R.; Morosoff, N.; Stannett, V.T.; Barker, R.H.

    1977-01-01

    Methodology has been developed for the grafting of vinyl functional organobromide and organophosphorus compounds on polyester fibers and 50/50 PET/cotton fabric. Procedures were developed for localized grafting of vinyl bromide (VBr) and diethylvinylphosphonate (DEVP) upon PET fibers. Oxygen index was used to evaluate the effect of the location of VBr and DEVP within the filament upon their flame retardance efficiencies. For the various bromine homopolymer grafts the apparent thermal stability of the graft and its flame retardance efficiency may be related to the alpha aliphatic hydrogen to bromine ratio. Using results from the polyester studies, techniques were devised for the treatment of 50/50 polyester/ cotton fabrics. Both homopolymer and copolymer grafts were evaluated but the greatest degree of success was attained using mixtures of phosphorus and bromine containing monomers. The results of these studies will be reviewed and their implications for development as commercial textile treatments discussed. (author)

  8. Non-invasive biomonitoring for PFRs and PSDEs: New insights in analysis of human hair externally exposed to selected flame retardants

    OpenAIRE

    Kucharska, Agnieszka; Covaci, Adrian; Vanermen, Guido; Voorspoels, Stefan

    2015-01-01

    Abstract: In this study, we investigated the hypothesis whether externally adsorbed and internally deposited flame retardants (FRs) in hair could be distinguished. To this extent, hair samples collected from one volunteer were exposed under controlled conditions to phosphate FR (PFR) and polybrominated diphenyl ether (PBDE) standards to mimic external contamination. Afterwards, suitable washing procedures to selectively remove contaminants from the hair surface were investigated. The samples ...

  9. Speciation analysis of arsenic by selective hydride generation- cryotrapping-atomic fluorescence spectrometry with flame-in-gas- shield atomizer: Achieving extremely low detection limits with inexpensive instrumentation

    Czech Academy of Sciences Publication Activity Database

    Musil, Stanislav; Matoušek, Tomáš; Currier, J. M.; Stýblo, M.; Dědina, Jiří

    2014-01-01

    Roč. 86, č. 20 (2014), s. 10422-10428 ISSN 0003-2700 R&D Projects: GA ČR GA14-23532S; GA MŠk LH12040 Institutional support: RVO:68081715 Keywords : speciation analysis of arsenic * selective hydride generation * flame-in-gas-shield atomizer * cryotrapping-atomic fluorescence spectrometry Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 5.636, year: 2014

  10. New insight into photo-bromination processes in saline surface waters: The case of salicylic acid

    International Nuclear Information System (INIS)

    Tamtam, Fatima; Chiron, Serge

    2012-01-01

    It was shown, through a combination of field and laboratory observations, that salicylic acid can undergo photo-bromination reactions in sunlit saline surface waters. Laboratory-scale experiments revealed that the photochemical yields of 5-bromosalicylic acid and 3,5-dibromosalicylic acid from salicylic acid were always low (in the 4% range at most). However, this might be of concern since these compounds are potential inhibitors of the 20α-hydroxysteroid dehydrogenase enzyme, with potential implications in endocrine disruption processes. At least two mechanisms were involved simultaneously to account for the photo-generation of brominated substances. The first one might involve the formation of reactive brominated radical species (Br·, Br 2 · − ) through hydroxyl radical mediated oxidation of bromide ions. These ions reacted more selectively than hydroxyl radicals with electron-rich organic pollutants such as salicylic acid. The second one might involve the formation of hypobromous acid, through a two electron oxidation of bromine ions by peroxynitrite. This reaction was catalyzed by nitrite, since these ions play a crucial role in the formation of nitric oxide upon photolysis. This nitric oxide further reacts with superoxide radical anions to yield peroxynitrite and by ammonium through the formation of N-bromoamines, probably due to the ability of N-bromoamines to promote the aromatic bromination of phenolic compounds. Field measurements revealed the presence of salicylic acid together with 5-bromosalicylic and 3,5-dibromosalicylic acid in a brackish coastal lagoon, thus confirming the environmental significance of the proposed photochemically induced bromination pathways. -- Highlights: ► Brominated derivatives of salicylic acid were detected in a brackish lagoon. ► A photochemical pathway was hypothesized to account for bromination of salicylic acid. ► Radical bromine species are partly responsible for the bromination process. ► Hypobromous acid

  11. Flame analysis using image processing techniques

    Science.gov (United States)

    Her Jie, Albert Chang; Zamli, Ahmad Faizal Ahmad; Zulazlan Shah Zulkifli, Ahmad; Yee, Joanne Lim Mun; Lim, Mooktzeng

    2018-04-01

    This paper presents image processing techniques with the use of fuzzy logic and neural network approach to perform flame analysis. Flame diagnostic is important in the industry to extract relevant information from flame images. Experiment test is carried out in a model industrial burner with different flow rates. Flame features such as luminous and spectral parameters are extracted using image processing and Fast Fourier Transform (FFT). Flame images are acquired using FLIR infrared camera. Non-linearities such as thermal acoustic oscillations and background noise affect the stability of flame. Flame velocity is one of the important characteristics that determines stability of flame. In this paper, an image processing method is proposed to determine flame velocity. Power spectral density (PSD) graph is a good tool for vibration analysis where flame stability can be approximated. However, a more intelligent diagnostic system is needed to automatically determine flame stability. In this paper, flame features of different flow rates are compared and analyzed. The selected flame features are used as inputs to the proposed fuzzy inference system to determine flame stability. Neural network is used to test the performance of the fuzzy inference system.

  12. Wastewater analysis of Census day samples to investigate per capita input of organophosphorus flame retardants and plasticizers into wastewater

    NARCIS (Netherlands)

    O'Brien, J.W.; Thai, P.K.; Brandsma, S.H.; Leonards, P.E.G.; Ort, C.; Mueller, J.F.

    2015-01-01

    The use of organophosphate esters (PFRs) as flame retardants and plasticizers has increased due to the ban of some brominated flame retardants. There is however some concern regarding the toxicity, particularly carcinogenicity and neurotoxicity, of some of the PFRs. In this study we applied

  13. Influences of the molecular fuel structure on combustion reactions towards soot precursors in selected alkane and alkene flames.

    Science.gov (United States)

    Ruwe, Lena; Moshammer, Kai; Hansen, Nils; Kohse-Höinghaus, Katharina

    2018-04-25

    In this study, we experimentally investigate the high-temperature oxidation kinetics of n-pentane, 1-pentene and 2-methyl-2-butene (2M2B) in a combustion environment using flame-sampling molecular beam mass spectrometry. The selected C5 fuels are prototypes for linear and branched, saturated and unsaturated fuel components, featuring different C-C and C-H bond structures. It is shown that the formation tendency of species, such as polycyclic aromatic hydrocarbons (PAHs), yielded through mass growth reactions increases drastically in the sequence n-pentane fuel-dependent reaction sequences of the gas-phase combustion mechanism that provide explanations for the observed difference in the PAH formation tendency. First, we investigate the fuel-structure-dependent formation of small hydrocarbon species that are yielded as intermediate species during the fuel decomposition, because these species are at the origin of the subsequent mass growth reaction pathways. Second, we review typical PAH formation reactions inspecting repetitive growth sequences in dependence of the molecular fuel structure. Third, we discuss how differences in the intermediate species pool influence the formation reactions of key aromatic ring species that are important for the PAH growth process underlying soot formation. As a main result it was found that for the fuels featuring a C[double bond, length as m-dash]C double bond, the chemistry of their allylic fuel radicals and their decomposition products strongly influences the combination reactions to the initially formed aromatic ring species and as a consequence, the PAH formation tendency.

  14. Brominated flame retardants in birds of prey from Flanders, Belgium

    Energy Technology Data Exchange (ETDEWEB)

    Voorspoels, S.; Covaci, A.; Schepens, P. [Antwerp Univ., Wilrijk (Belgium). Toxicological Centre

    2004-09-15

    Since their introduction on the market, environmental levels of polybrominated diphenyl ethers (PBDEs) are continuously increasing. This is caused by spillage and emission during production and use, but also by improper disposal at the end-of-life of the products in which they are used. These chemicals are highly persistent and lipophilic which results in bioaccumulation in fatty tissues of biota and biomagnification throughout the food chain. Because PBDEs have a high toxicological potential, this biomagnification can have serious health consequences for top-predators, such as birds of prey. Data about PBDE concentrations in terrestrial biota, especially in birds of prey, is scarce. A rapid increase of PBDE concentrations has been seen in pooled guillemot (Uria algae) eggs from the Baltic proper7 during the late 1970's and early 1980's, followed by a decrease during the 1990's8. In herring gull eggs from the Great Lakes, the PBDE concentrations increased exponentially from 1981 to 2000. Most of the studies look at concentrations in eggs, while less is known about tissue levels and distribution of these pollutants in birds of prey.

  15. Flame Length

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Flame length was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The tool...

  16. Electronic properties of bromine-doped carbon nanotubes

    CERN Document Server

    Jhi, S H; Cohen, M L

    2002-01-01

    Intercalation of bromine molecules (Br2) into single-wall carbon nanotube (SWNT) ropes is studied using the ab initio pseudopotential density functional method. Electronic and vibrational properties of the SWNT and Br2 are studied for various bromine concentrations. A drastic change in the charge transfer, bromine stretching-mode, and bromine bond-length is observed when the bromine-bromine distance decreases. Calculated electronic structures show that, at high bromine concentrations, the bromine ppsigma level broadens due to the interbromine interaction. These states overlap with the electronic bands of the SWNT near the Fermi level which results in a substantial charge transfer from carbon to bromine.

  17. One-step synthesis of bismuth molybdate catalysts via flame spray pyrolysis for the selective oxidation of propylene to acrolein

    DEFF Research Database (Denmark)

    Schuh, K.; Kleist, W.; Høj, Martin

    2014-01-01

    Flame spray pyrolysis (FSP) of Bi(III)-and Mo(VI)-2-ethylhexanoate dissolved in xylene resulted in various nanocrystalline bismuth molybdate phases depending on the Bi/Mo ratio. Besides alpha-Bi2Mo3O12 and gamma-Bi2MoO6, FSP gave direct access to the metastable beta-Bi2Mo2O9 phase with high surfa...

  18. 凝胶渗透色谱-固相萃取结合色谱-质谱法测定乳制品中18种溴系阻燃剂%Determination of 18 Brominated Flame Retardants in Dairy Product by Gel Permeation Chromatography-Solid Phase Extraction Coupled to Gas Chromatography-Mass Spectrometry and High Performance Liquid Chromatography-Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    李健; 王翼飞; 周显青; 施致雄

    2016-01-01

    A novel method was developed for the simultaneous determination of 6 novel brominated flame retardants ( NBFRs) , 8 polybrominated diphenyl ethers ( PBDEs) , tetrabromobisphenolA ( TBBPA) and α,β,γ-hexabromocyclododecane (α, β, γ-HBCD ) in dairy product. Dairy product samples were extracted using soxhlet extraction with acetone/hexane (1:1, V/V). The removal of co-extracted materials was achieved by gel permeation chromatography followed by acidified silica treatment. The fractionation of the PBDEs/NBFRs and HBCD/TBBPA was performed using a Supelco LC-Si SPE cartridge. The detection of the PBDEs and NBFRs was then performed by GC-NCI/MS, and that of the HBCDs and the TBBPA was performed using HPLC-MS/MS. A recovery test was performed using a matrix spiking test and for most of the analytes the recoveries ranged from 80 . 1% to 114 . 7% with RSDs equal to or lower than 14 . 9%. The LODs were 0 . 2-119. 2 pg/g. This methodology was validated to be accurate and sensitive for the simultaneous pretreatment and analysis of brominated flame retardants in dairy product.%采用索氏提取、凝胶渗透色谱和固相萃取技术作为前处理方法,建立乳制品中6种新型溴系阻燃剂、8种多溴联苯醚、四溴双酚A和α、β、γ-六溴环十二烷异构体共18种溴系阻燃剂的同时提取与净化方法,并结合气相色谱-负化学源质谱法(GC-NCI/MS)和高效液相色谱-电喷雾电离-串联质谱法(HPLC-ESI-MS/MS)进行检测。奶样经冷冻干燥后以正己烷-丙酮(1:1, V/V)索氏提取,采用凝胶渗透色谱结合酸化硅胶柱净化,随后以LC-Si固相萃取柱分离气相和液相待测物。以GC-NCI/MS测定6种新型溴系阻燃剂和8种多溴联苯醚,以HPLC-MS/MS检测四溴双酚A和六溴环十二烷异构体,内标法定量。结果表明,以空白牛奶样品为加标基质,多数待测物平均回收率为80.1%~114.7%,方法具有良好的精密度(多数待测物相对标准偏差( RSD)在0.87%~14.9%)

  19. Detection of halogenated flame retardants in polyurethane foam by particle induced X-ray emission

    International Nuclear Information System (INIS)

    Maley, Adam M.; Falk, Kyle A.; Hoover, Luke; Earlywine, Elly B.; Seymour, Michael D.; DeYoung, Paul A.; Blum, Arlene; Stapleton, Heather M.; Peaslee, Graham F.

    2015-01-01

    A novel application of particle-induced X-ray emission (PIXE) has been developed to detect the presence of chlorinated and brominated flame retardant chemicals in polyurethane foams. Traditional Gas Chromatography–Mass Spectrometry (GC–MS) methods for the detection and identification of halogenated flame retardants in foams require extensive sample preparation and data acquisition time. The elemental analysis of the halogens in polyurethane foam performed by PIXE offers the opportunity to identify the presence of halogenated flame retardants in a fraction of the time and sample preparation cost. Through comparative GC–MS and PIXE analysis of 215 foam samples, excellent agreement between the two methods was obtained. These results suggest that PIXE could be an ideal rapid screening method for the presence of chlorinated and brominated flame retardants in polyurethane foams

  20. Detection of halogenated flame retardants in polyurethane foam by particle induced X-ray emission

    Energy Technology Data Exchange (ETDEWEB)

    Maley, Adam M.; Falk, Kyle A.; Hoover, Luke; Earlywine, Elly B.; Seymour, Michael D. [Department of Chemistry, Hope College, 35 E. 12th Street, Holland, MI 49423 (United States); DeYoung, Paul A. [Department of Physics, Hope College, 27 Graves Place, Holland, MI 49423 (United States); Blum, Arlene [Green Science Policy Institute, Box 5455, Berkeley, CA 94705 (United States); Stapleton, Heather M. [Nicholas School of the Environment, Duke University, LSRC Box 90328, Durham, NC 27708 (United States); Peaslee, Graham F., E-mail: peaslee@hope.edu [Department of Chemistry, Hope College, 35 E. 12th Street, Holland, MI 49423 (United States)

    2015-09-01

    A novel application of particle-induced X-ray emission (PIXE) has been developed to detect the presence of chlorinated and brominated flame retardant chemicals in polyurethane foams. Traditional Gas Chromatography–Mass Spectrometry (GC–MS) methods for the detection and identification of halogenated flame retardants in foams require extensive sample preparation and data acquisition time. The elemental analysis of the halogens in polyurethane foam performed by PIXE offers the opportunity to identify the presence of halogenated flame retardants in a fraction of the time and sample preparation cost. Through comparative GC–MS and PIXE analysis of 215 foam samples, excellent agreement between the two methods was obtained. These results suggest that PIXE could be an ideal rapid screening method for the presence of chlorinated and brominated flame retardants in polyurethane foams.

  1. Refractory concentrate gold leaching: Cyanide vs. bromine

    Science.gov (United States)

    Dadgar, Ahmad

    1989-12-01

    Gold extraction, recovery and economics for two refractory concentrates were investigated using cyanide and bromine reagents. Gold extractions for cyanide leaching (24-48 hours) and bromine leaching (six hours) were the same and ranged from 94 to 96%. Gold recoveries from bromine pregnant solutions using carbon adsorption, ion exchange, solvent extraction, and zinc and aluminum precipitation methods were better than 99.9%. A preliminary economic analysis indicates that chemical costs for cyanidation and bromine process are 11.70 and 11.60 respectively, per tonne of calcine processed.

  2. Flames in vortices & tulip-flame inversion

    Science.gov (United States)

    Dold, J. W.

    This article summarises two areas of research regarding the propagation of flames in flows which involve significant fluid-dynamical motion [1]-[3]. The major difference between the two is that in the first study the fluid motion is present before the arrival of any flame and remains unaffected by the flame [1, 2] while, in the second study it is the flame that is responsible for all of the fluid dynamical effects [3]. It is currently very difficult to study flame-motion in which the medium is both highly disturbed before the arrival of a flame and is further influenced by the passage of the flame.

  3. Magnetic trapping of cold bromine atoms.

    Science.gov (United States)

    Rennick, C J; Lam, J; Doherty, W G; Softley, T P

    2014-01-17

    Magnetic trapping of bromine atoms at temperatures in the millikelvin regime is demonstrated for the first time. The atoms are produced by photodissociation of Br2 molecules in a molecular beam. The lab-frame velocity of Br atoms is controlled by the wavelength and polarization of the photodissociation laser. Careful selection of the wavelength results in one of the pair of atoms having sufficient velocity to exactly cancel that of the parent molecule, and it remains stationary in the lab frame. A trap is formed at the null point between two opposing neodymium permanent magnets. Dissociation of molecules at the field minimum results in the slowest fraction of photofragments remaining trapped. After the ballistic escape of the fastest atoms, the trapped slow atoms are lost only by elastic collisions with the chamber background gas. The measured loss rate is consistent with estimates of the total cross section for only those collisions transferring sufficient kinetic energy to overcome the trapping potential.

  4. Algae form brominated organic compounds in surface waters

    Energy Technology Data Exchange (ETDEWEB)

    Huetteroth, A; Putschew, A; Jekel, M [Tech. Univ. Berlin (Germany)

    2004-09-15

    Monitoring of organic halogen compounds, measured as adsorbable organic bromine (AOBr) revealed seasonal high concentrations of organic bromine compounds in a surface water (Lake Tegel, Berlin, Germany). Usually, in late summer, concentrations are up to five times higher than during the rest of the year. The AOBr of the lake inflows (throughout the year less then 6 {mu}g/L) were always lower then those in the lake, which indicates a production of AOBr in the lake. A correlation of the AOBr and chlorophyll-a concentration (1) in the lake provides first evidence for the influence of phototrophic organisms. The knowledge of the natural production of organohalogens is relatively recent. Up to now there are more then 3800 identified natural organohalogen compounds that have been detected in marine plants, animals, and bacteria and also in terrestrial plants, fungi, lichen, bacteria, insects, some higher animals, and humans. Halogenated organic compounds are commonly considered to be of anthropogenic origin; derived from e.g. pharmaceuticals, herbicides, fungicides, insecticides, flame retardants, intermediates in organic synthesis and solvents. Additionally they are also produced as by-products during industrial processes and by waste water and drinking water disinfection. Organohalogen compounds may be toxic, persistent and/or carcinogenic. In order to understand the source and environmental relevance of naturally produced organobromine compounds in surface waters, the mechanism of the formation was investigated using batch tests with lake water and algae cultures.

  5. Regional variation and possible sources of brominated contaminants in breast milk from Japan

    International Nuclear Information System (INIS)

    Fujii, Yukiko; Ito, Yoshiko; Harada, Kouji H.; Hitomi, Toshiaki; Koizumi, Akio; Haraguchi, Koichi

    2012-01-01

    This study focuses on the regional trends and possible sources of brominated organic contaminants accumulated in breast milk from mothers in southeastern (Okinawa) and northwestern (Hokkaido) areas of Japan. For persistent brominated flame retardants, polybrominated diphenyl ethers (PBDEs; major components, BDE-47 and BDE-153) were distributed at higher levels in mothers from Okinawa (mean, 2.1 ng/g lipid), while hexabromobenzene (HeBB) and its metabolite 1,2,4,5-tetrabromobenzene were more abundantly detected in mothers from Hokkaido (0.86 and 2.6 ng/g lipid), suggesting that there are regional differences in their exposure in Japan. We also detected naturally produced brominated compounds, one of which was identified as 2′-methoxy-2,3′,4,5′-tetrabromodiphenyl ether (2′-MeO-BDE68) at higher levels in mothers from Okinawa (0.39 ng/g lipid), while the other was identified as 3,3′,4,4′-tetrabromo-5,5′-dichloro-2,2′-dimethyl-1,1′-bipyrrole in mothers from Hokkaido (0.45 ng/g lipid). The regional variation may be caused by source differences, i.e. southern seafood for MeO-PBDEs and northern biota for halogenated bipyrroles in the Japanese coastal water. - Highlights: ► In this study, we detected brominated organic contaminants in Japanese breast milk. ► Naturally produced brominated organic contaminants were also detected. ► Northern and southern Japan showed regional differences in these contaminants. ► Exposure to the contaminants is suggested to arise from different specific sources. - Brominated organic contaminants were detected in Japanese breast milk.

  6. Bromine pretreated chitosan for adsorption of lead

    Indian Academy of Sciences (India)

    Pollution by heavy metals like lead (II) is responsible for health hazards and environmental degradation. Adsorption is a prevalent method applied for removal of heavy metal pollutants from water. This study explored adsorption performances of 30% bromine pretreated chitosan for lead (II) abatement from water. Bromine ...

  7. Regulated and Unregulated Halogenated Flame Retardants in Peregrine Falcon Eggs from Greenland

    DEFF Research Database (Denmark)

    Vorkamp, Katrin; Falk, Knud; Møller, Søren

    2018-01-01

    Median levels of regulated flame retardants, i.e. polybrominated diphenyl ethers (PBDEs), brominated biphenyl (BB) 153 and hexabromocyclododecane (HBCD) in 33-48 eggs of peregrine falcons (Falco peregrinus) from Greenland were 1900, 359 and 5.98 ng/g lipid weight (lw) and generally intermediate...

  8. New insight into photo-bromination processes in saline surface waters: The case of salicylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Tamtam, Fatima; Chiron, Serge, E-mail: serge.chiron@msem.univ-montp2.fr

    2012-10-01

    It was shown, through a combination of field and laboratory observations, that salicylic acid can undergo photo-bromination reactions in sunlit saline surface waters. Laboratory-scale experiments revealed that the photochemical yields of 5-bromosalicylic acid and 3,5-dibromosalicylic acid from salicylic acid were always low (in the 4% range at most). However, this might be of concern since these compounds are potential inhibitors of the 20{alpha}-hydroxysteroid dehydrogenase enzyme, with potential implications in endocrine disruption processes. At least two mechanisms were involved simultaneously to account for the photo-generation of brominated substances. The first one might involve the formation of reactive brominated radical species (Br{center_dot}, Br{sub 2}{center_dot}{sup -}) through hydroxyl radical mediated oxidation of bromide ions. These ions reacted more selectively than hydroxyl radicals with electron-rich organic pollutants such as salicylic acid. The second one might involve the formation of hypobromous acid, through a two electron oxidation of bromine ions by peroxynitrite. This reaction was catalyzed by nitrite, since these ions play a crucial role in the formation of nitric oxide upon photolysis. This nitric oxide further reacts with superoxide radical anions to yield peroxynitrite and by ammonium through the formation of N-bromoamines, probably due to the ability of N-bromoamines to promote the aromatic bromination of phenolic compounds. Field measurements revealed the presence of salicylic acid together with 5-bromosalicylic and 3,5-dibromosalicylic acid in a brackish coastal lagoon, thus confirming the environmental significance of the proposed photochemically induced bromination pathways. -- Highlights: Black-Right-Pointing-Pointer Brominated derivatives of salicylic acid were detected in a brackish lagoon. Black-Right-Pointing-Pointer A photochemical pathway was hypothesized to account for bromination of salicylic acid. Black

  9. short communication polyvinylpyrrolidone-bromine complex

    African Journals Online (AJOL)

    Preferred Customer

    Benzylic bromides were conveniently obtained in high yields via the reaction of the corresponding alcohols with crosslinked polyvinylpyrrolidone-bromine ... The traditional methods include highly toxic reagent such as HBr gas [3], BBr3 [4, ...

  10. Systematic vibration thermodynamic properties of bromine

    Science.gov (United States)

    Liu, G. Y.; Sun, W. G.; Liao, B. T.

    2015-11-01

    Based on the analysis of the maturity and finiteness of vibrational levels of bromine molecule in ground state and evaluating the effect on statistical computation, according to the elementary principles of quantum statistical theorem, using the full set of bromine molecular vibrational levels determined with algebra method, the statistical contribution for bromine systematical macroscopic thermodynamic properties is discussed. Thermodynamic state functions Helmholtz free energy, entropy and observable vibration heat capacity are calculated. The results show that the determination of full set of vibrational levels and maximum vibrational quantum number is the key in the correct statistical analysis of bromine systematical thermodynamic property. Algebra method results are clearly different from data of simple harmonic oscillator and the related algebra method results are no longer analytical but numerical and are superior to simple harmonic oscillator results. Compared with simple harmonic oscillator's heat capacities, the algebra method's heat capacities are more consistent with the experimental data in the given temperature range of 600-2100 K.

  11. Bromine accumulation in acidic black colluvial soils

    Science.gov (United States)

    Martínez Cortizas, Antonio; Ferro Vázquez, Cruz; Kaal, Joeri; Biester, Harald; Costa Casais, Manuela; Taboada Rodríguez, Teresa; Rodríguez Lado, Luis

    2016-02-01

    Recent investigations showed that bromine is incorporated to soil organic matter (SOM), its content increasing with humification. But few research was done on its long-term accumulation and the role played by pedogenetic processes, as those involved in organic matter stabilization. We investigated bromine content and distribution in four deep, acidic, organic-rich, Holocene soils from an oceanic area of Western Europe. Bromine concentrations (93-778 μg g-1) in the silt + clay (stabilized as aluminium-OM associations, and to a lesser extent on soil acidity (pH) and iron-OM associations. Thus, at scales of thousands of years, bromine accumulation in acidic soils is linked to the pool of metal-clay-stabilized organic matter.

  12. Flame Structure and Chemiluminescence Emissions of Inverse Diffusion Flames under Sinusoidally Driven Plasma Discharges

    Directory of Open Access Journals (Sweden)

    Maria Grazia De Giorgi

    2017-03-01

    Full Text Available Reduction of nitric oxides (NOx in aircraft engines and in gas turbines by lean combustion is of great interest in the design of novel combustion systems. However, the stabilization of the flame under lean conditions is a main issue. In this context, the present work investigates the effects of sinusoidal dielectric barrier discharge (DBD on a lean inverse diffusive methane/air flame in a Bunsen-type burner under different actuation conditions. The flame appearance was investigated with fixed methane loading (mass flux, but with varying inner airflow rate. High-speed flame imaging was done by using an intensified (charge-coupled device CCD camera equipped with different optical filters in order to selectively record signals from the chemiluminescent species OH*, CH*, or CO2* to evaluate the flame behavior in presence of plasma actuation. The electrical power consumption was less than 33 W. It was evident that the plasma flame enhancement was significantly influenced by the plasma discharges, particularly at high inner airflow rates. The flame structure changes drastically when the dissipated plasma power increases. The flame area decreases due to the enhancement of mixing and chemical reactions that lead to a more anchored flame on the quartz exit with a reduction of the flame length.

  13. Flame-vortex interaction and mixing behaviors of turbulent non-premixed jet flames under acoustic forcing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Munki; Choi, Youngil; Oh, Jeongseog; Yoon, Youngbin [School of Mechanical and Aerospace Engineering, Seoul National University, Seoul (Korea)

    2009-12-15

    This study examines the effect of acoustic excitation using forced coaxial air on the flame characteristics of turbulent hydrogen non-premixed flames. A resonance frequency was selected to acoustically excite the coaxial air jet due to its ability to effectively amplify the acoustic amplitude and reduce flame length and NO{sub x} emissions. Acoustic excitation causes the flame length to decrease by 15% and consequently, a 25% reduction in EINO{sub x} is achieved, compared to coaxial air flames without acoustic excitation at the same coaxial air to fuel velocity ratio. Moreover, acoustic excitation induces periodical fluctuation of the coaxial air velocity, thus resulting in slight fluctuation of the fuel velocity. From phase-lock PIV and OH PLIF measurement, the local flow properties at the flame surface were investigated under acoustic forcing. During flame-vortex interaction in the near field region, the entrainment velocity and the flame surface area increased locally near the vortex. This increase in flame surface area and entrainment velocity is believed to be a crucial factor in reducing flame length and NO{sub x} emission in coaxial jet flames with acoustic excitation. Local flame extinction occurred frequently when subjected to an excessive strain rate, indicating that intense mass transfer of fuel and air occurs radially inward at the flame surface. (author)

  14. Manganese dioxide causes spurious gold values in flame atomic-absorption readings from HBr-Br2 digestions

    Science.gov (United States)

    Campbell, W.L.

    1981-01-01

    False readings, apparently caused by the presence of high concentrations of manganese dioxide, have been observed in our current flame atomic-absorption procedure for the determination of gold. After a hydrobromic acid (HBr)-bromine (Br2) leach, simply heating the sample to boiling to remove excess Br2 prior to extraction with methyl-isobutyl-ketone (MIBK) eliminates these false readings. ?? 1981.

  15. Using a rainforest-flame forest mosaic to test the hypothesis that leaf and litter fuel flammability is under natural selection.

    Science.gov (United States)

    Clarke, Peter J; Prior, Lynda D; French, Ben J; Vincent, Ben; Knox, Kirsten J E; Bowman, David M J S

    2014-12-01

    We used a mosaic of infrequently burnt temperate rainforest and adjacent, frequently burnt eucalypt forests in temperate eastern Australia to test whether: (1) there were differences in flammability of fresh and dried foliage amongst congeners from contrasting habitats, (2) habitat flammability was related to regeneration strategy, (3) litter fuels were more flammable in frequently burnt forests, (4) the severity of a recent fire influenced the flammability of litter (as this would suggest fire feedbacks), and (5) microclimate contributed to differences in fire hazard amongst habitats. Leaf-level comparisons were made among 11 congeneric pairs from rainforest and eucalypt forests. Leaf-level ignitability, combustibility and sustainability were not consistently higher for taxa from frequently burnt eucalypt forests, nor were they higher for species with fire-driven recruitment. The bulk density of litter-bed fuels strongly influenced flammability, but eucalypt forest litter was not less dense than rainforest litter. Ignitability, combustibility and flame sustainability of community surface fuels (litter) were compared using fuel arrays with standardized fuel mass and moisture content. Forests previously burned at high fire severity did not have consistently higher litter flammability than those burned at lower severity or long unburned. Thus, contrary to the Mutch hypothesis, there was no evidence of higher flammability of litter fuels or leaves from frequently burnt eucalypt forests compared with infrequently burnt rainforests. We suggest the manifest pyrogenicity of eucalypt forests is not due to natural selection for more flammable foliage, but better explained by differences in crown openness and associated microclimatic differences.

  16. Determination of polychlorinated biphenyls, selected persistent organochlorine pesticides, and polybrominated flame retardants in fillets of fishes from the 2007 Missouri Department of Conservation Monitoring Program

    Science.gov (United States)

    Gale, Robert W.; Orazio, Carl E.; McKee, Michael J.

    2009-01-01

    This report presents the results of a study to determine polychlorinated biphenyl, organochlorine pesticide, and polybrominated diphenylether flame retardant concentrations in selected fishes from lakes and streams across Missouri. Fillets were collected from each fish sample and after homogenization, compositing, and preparation, analyte concentrations were determined with dual column capillary gas chromatography-electron-capture detection. Total concentrations of polychlorinated biphenyls in samples ranged from background levels of about 50 to 300 nanograms per gram. In samples with elevated contaminant concentrations, chlordanes, DDT-related chemicals, and dieldrin constituted the primary classes of pesticides present, and ranged from 5 to 75 nanograms per gram. Total concentrations of polybrominated diphenyl ethers in samples ranged from background levels of 5 to 86 nanograms per gram. Channel catfish from the upper and lower Blue River and lake sturgeon from the Mississippi River at Saverton exhibited different polybrominated diphenyl ethers ratios. Concentrations of polychlorinated biphenyls, chlordanes, DDT-related compounds, and polybrominated diphenyl ethers all were greatest in samples of channel catfish from the upper and lower Blue River, and in samples of lake sturgeon from the Mississippi River at Saverton.

  17. Environmental analysis of higher brominated diphenyl ethers and decabromodiphenyl ethane.

    Science.gov (United States)

    Kierkegaard, Amelie; Sellström, Ulla; McLachlan, Michael S

    2009-01-16

    Methods for environmental analysis of higher brominated diphenyl ethers (PBDEs), in particular decabromodiphenyl ether (BDE209), and the recently discovered environmental contaminant decabromodiphenyl ethane (deBDethane) are reviewed. The extensive literature on analysis of BDE209 has identified several critical issues, including contamination of the sample, degradation of the analyte during sample preparation and GC analysis, and the selection of appropriate detection methods and surrogate standards. The limited experience with the analysis of deBDethane suggests that there are many commonalities with BDE209. The experience garnered from the analysis of BDE209 over the last 15 years will greatly facilitate progress in the analysis of deBDethane.

  18. Preparation of bromine fluoride; Preparation du fluorure de brome

    Energy Technology Data Exchange (ETDEWEB)

    Domange, Pr; Duflo, J.

    1958-05-15

    This note addresses the preparation of bromine fluoride. It indicates the implemented process for the reaction, used products (fluorine and bromine), and column characteristics. It describes the operating mode. Apparatus drawing is provided.

  19. Flame structure of methane inverse diffusion flame

    KAUST Repository

    Elbaz, Ayman M.

    2014-07-01

    This paper presents high speed images of OH-PLIF at 10. kHz simultaneously with 2D PIV (particle image velocimetry) measurements collected along the entire length of an inverse diffusion flame with circumferentially arranged methane fuel jets. For a fixed fuel flow rate, the central air jet Re was varied, leading to four air to fuel velocity ratios, namely Vr = 20.7, 29, 37.4 and 49.8. A double flame structure could be observed composed of a lower fuel entrainment region and an upper mixing and intense combustion region. The entrainment region was enveloped by an early OH layer, and then merged through a very thin OH neck to an annular OH layer located at the shear layer of the air jet. The two branches of this annular OH layer broaden as they moved downstream and eventfully merged together. Three types of events were observed common to all flames: breaks, closures and growing kernels. In upstream regions of the flames, the breaks were counterbalanced by flame closures. These breaks in OH signal were found to occur at locations where locally high velocity flows were impinging on the flame. As the Vr increased to 37.4, the OH layers became discontinuous over the downstream region of the flame, and these regions of low or no OH moved upstream. With further increases in Vr, these OH pockets act as flame kernels, growing as they moved downstream, and became the main mechanism for flame re-ignition. Along the flame length, the direction of the two dimensional principle compressive strain rate axis exhibited a preferred orientation of approximately 45° with respect to the flow direction. Moreover, the OH zones were associated with elongated regions of high vorticity. © 2013 Elsevier Inc.

  20. On the Flame Height Definition for Upward Flame Spread

    OpenAIRE

    Consalvi, Jean L; Pizzo, Yannick; Porterie, Bernard; Torero, Jose L

    2007-01-01

    Flame height is defined by the experimentalists as the average position of the luminous flame and, consequently is not directly linked with a quantitative value of a physical parameter. To determine flame heights from both numerical and theoretical results, a more quantifiable criterion is needed to define flame heights and must be in agreement with the experiments to allow comparisons. For wall flames, steady wall flame experiments revealed that flame height may be define...

  1. Structure and functionality of bromine doped graphite.

    Science.gov (United States)

    Hamdan, Rashid; Kemper, A F; Cao, Chao; Cheng, H P

    2013-04-28

    First-principles calculations are used to study the enhanced in-plane conductivity observed experimentally in Br-doped graphite, and to study the effect of external stress on the structure and functionality of such systems. The model used in the numerical calculations is that of stage two doped graphite. The band structure near the Fermi surface of the doped systems with different bromine concentrations is compared to that of pure graphite, and the charge transfer between carbon and bromine atoms is analyzed to understand the conductivity change along different high symmetry directions. Our calculations show that, for large interlayer separation between doped graphite layers, bromine is stable in the molecular form (Br2). However, with increased compression (decreased layer-layer separation) Br2 molecules tend to dissociate. While in both forms, bromine is an electron acceptor. The charge exchange between the graphite layers and Br atoms is higher than that with Br2 molecules. Electron transfer to the Br atoms increases the number of hole carriers in the graphite sheets, resulting in an increase of conductivity.

  2. short communication polyvinylpyrrolidone-bromine complex

    African Journals Online (AJOL)

    Preferred Customer

    2011-06-15

    2Department of Organic-Polymer Chemistry, Mazandaran University, Babolsar, Iran. (Received June 15, 2011; revised January 11, 2012). ABSTRACT. Benzylic bromides were conveniently obtained in high yields via the reaction of the corresponding alcohols with crosslinked polyvinylpyrrolidone-bromine complex ...

  3. Flame and flameless atomic-absorption determination of tellurium in geological materials

    Science.gov (United States)

    Chao, T.T.; Sanzolone, R.F.; Hubert, A.E.

    1978-01-01

    The sample is digested with a solution of hydrobromic acid and bromine and the excess of bromine is expelled. After dilution of the solution to approximately 3 M in hydrobromic acid, ascorbic acid is added to reduce iron(III) before extraction of tellurium into methyl isobutyl ketone (MIBK). An oxidizing air-acetylene flame is used to determine tellurium in the 0.1-20 ppm range. For samples containing 4-200 ppb of tellurium, a carbon-rod atomizer is used after the MIBK extract has been washed with 0.5 M hydrobromic acid to remove the residual iron. The flame procedure is useful for rapid preliminary monitoring, and the flameless procedure can determine tellurium at very low concentrations. ?? 1978.

  4. A novel lead imprinted polymer as the selective solid phase for extraction and trace detection of lead ions by flame atomic absorption spectrophotometry: Synthesis, characterization and analytical application

    Directory of Open Access Journals (Sweden)

    Homeira Ebrahimzadeh

    2017-05-01

    Full Text Available A novel ion imprinted polymer as the selective solid phase combined with flame atomic absorption spectrometry (FAAS was applied for preconcentration and determination of lead in real samples. In the first step, Pb(II-IIP was synthesized by copolymerization of 2-vinyl pyridine as the functional monomer, ethylene glycol dimethacrylate as the cross-linker, 2,2-azobisisobutyronitrile as the initiator that imprinted with Pb(II as the template ion, 2-amino pyridine as the ligand. Subsequently, the imprinted Pb(II was completely removed by leaching the dried and powdered imprinted polymer with HCl (2 mol L−1. This polymer was characterized by Fourier Transform Infrared (FT-IR spectrometer. The effect of different variables on the extraction efficiency such as type and volume of eluent for extraction, solution’s pH for adsorption, sorption and desorption times was evaluated. Under the optimum conditions: type of eluent, HCl (2 mol L−1; volume of eluent, 5 mL; solution’s pH for sorption, 5; sorption time, 90 min; desorption time, 125 min and breakthrough volume of 750 mL were obtained. Preconcentration factor of the method was about 150. The limit of detection was obtained 0.75 μg L−1 and a dynamic linear range (DLR of 3–150 μg L−1 was found. The maximum sorption retention capacity of Pb(II ions on the imprinted polymer was 85.6 mg g−1. The prepared ion-imprinted polymer particles have an increased selectivity toward Pb(II ions over a range of competing metal ions with the same charge and similar ionic radius. Performance of the present method was evaluated for extraction and determination of Pb(II in water samples at microgram per liter concentration and satisfactory results were obtained (RSD = 2.7%.

  5. Environmental Impact of Flame Retardants (Persistence and Biodegradability

    Directory of Open Access Journals (Sweden)

    Asher Brenner

    2009-02-01

    Full Text Available Flame-retardants (FR are a group of anthropogenic environmental contaminants used at relatively high concentrations in many applications. Currently, the largest market group of FRs is the brominated flame retardants (BFRs. Many of the BFRs are considered toxic, persistent and bioaccumulative. Bioremediation of contaminated water, soil and sediments is a possible solution for the problem. However, the main problem with this approach is the lack of knowledge concerning appropriate microorganisms, biochemical pathways and operational conditions facilitating degradation of these chemicals at an acceptable rate. This paper reviews and discusses current knowledge and recent developments related to the environmental fate and impact of FRs in natural systems and in engineered treatment processes.

  6. Lifted Turbulent Jet Flames

    Science.gov (United States)

    1993-04-14

    flame length L simultaneously with h, and measuring the visible radiation I simultaneously with h. L(t) was found to be nearly uncorrelated with h(t...variation of 7i/2 /76 with ýh. These experiments included measuring the flame length L simultaneously with h, and measuring the visible radiation I...Measurements of Liftoff Height and Flame Length ... 66 4.5 Simultaneous Measurements of Liftoff Height and Radiation ....... 71 4.6 D scussion

  7. Nanocellular foam with solid flame retardant

    Science.gov (United States)

    Chen, Liang; Kelly-Rowley, Anne M.; Bunker, Shana P.; Costeux, Stephane

    2017-11-21

    Prepare nanofoam by (a) providing an aqueous solution of a flame retardant dissolved in an aqueous solvent, wherein the flame retardant is a solid at 23.degree. C. and 101 kiloPascals pressure when in neat form; (b) providing a fluid polymer composition selected from a solution of polymer dissolved in a water-miscible solvent or a latex of polymer particles in a continuous aqueous phase; (c) mixing the aqueous solution of flame retardant with the fluid polymer composition to form a mixture; (d) removing water and, if present, solvent from the mixture to produce a polymeric composition having less than 74 weight-percent flame retardant based on total polymeric composition weight; (e) compound the polymeric composition with a matrix polymer to form a matrix polymer composition; and (f) foam the matrix polymer composition into nanofoam having a porosity of at least 60 percent.

  8. Membrane-less hydrogen bromine flow battery

    Science.gov (United States)

    Braff, William A.; Bazant, Martin Z.; Buie, Cullen R.

    2013-08-01

    In order for the widely discussed benefits of flow batteries for electrochemical energy storage to be applied at large scale, the cost of the electrochemical stack must come down substantially. One promising avenue for reducing stack cost is to increase the system power density while maintaining efficiency, enabling smaller stacks. Here we report on a membrane-less hydrogen bromine laminar flow battery as a potential high-power density solution. The membrane-less design enables power densities of 0.795 W cm-2 at room temperature and atmospheric pressure, with a round-trip voltage efficiency of 92% at 25% of peak power. Theoretical solutions are also presented to guide the design of future laminar flow batteries. The high-power density achieved by the hydrogen bromine laminar flow battery, along with the potential for rechargeable operation, will translate into smaller, inexpensive systems that could revolutionize the fields of large-scale energy storage and portable power systems.

  9. Symproportionation versus Disproportionation in Bromine Redox Systems

    International Nuclear Information System (INIS)

    Toporek, Marcin; Michałowska-Kaczmarczyk, Anna M.; Michałowski, Tadeusz

    2015-01-01

    Graphical abstract: Display Omitted -- Highlights: • The disproportionation and symproportionation of bromine in different media is presented. • All the redox systems are elaborated according to the principles of the generalized approach to electrolytic redox systems (GATES/GEB). • All physicochemical knowledge is involved in the algorithm applied for this purpose. • The graphical representation of the systems is the basis of gaining the detailed physicochemical knowledge on the systems in question. -- Abstract: The paper refers to dynamic (titration) redox systems where symproportionation or disproportionation of bromine species occur. The related systems are modeled according to principles assumed in the Generalized Approach to Electrolytic Redox Systems (GATES), with Generalized Electron Balance (GEB) concept involved in the GATES/GEB software. The results obtained from calculations made with use of iterative computer programs prepared according to MATLAB computational software, are presented graphically, as 2D and 3D graphs

  10. Membrane-less hydrogen bromine flow battery

    OpenAIRE

    Braff, W. A.; Bazant, M. Z.; Buie, C. R.

    2014-01-01

    In order for the widely discussed benefits of flow batteries for electrochemical energy storage to be applied at large scale, the cost of the electrochemical stack must come down substantially. One promising avenue for reducing stack cost is to increase the system power density while maintaining efficiency, enabling smaller stacks. Here we report on a membrane-less, hydrogen bromine laminar flow battery as a potential high power density solution. The membrane-less design enables power densiti...

  11. One-step fabrication of novel superhydrophobic and superoleophilic sponge with outstanding absorbency and flame-retardancy for the selective removal of oily organic solvent from water

    Science.gov (United States)

    Xiang, Yuqian; Pang, Youyou; Jiang, Xiaomei; Huang, Jie; Xi, Fengna; Liu, Jiyang

    2018-01-01

    Absorbent materials integrated with superhydrophobicity, superoleophilicity and flame-retardancy are highly desired in the adsorption/removal of flammable oils/organic compounds as well as reducing the risk of fire and explosion. Here, one-step fabrication of novel superhydrophobic and superoleophilic sponge with outstanding absorbency and flame-retardancy was presented. Using raw melamine (ME) sponge as the supporting matrix, the formation of polydopamine (PDA) nanoaggregates via in-situ self-polymerization of high-concentrated dopamine and the covalent grafting of hydrophobic n-dodecylthiol (DT) onto PDA were combined in a feasible alkaline water/ethanol medium. As investigated by scanning electron microscopy (SEM) and X-ray energy-dispersive spectroscopy (EDS), the as-prepared ME/PDA/DT sponge possessed hierarchical structure with submicron PDA nanoaggregates containing DT motif (low surface energy) on 3D interconnected porous network. It exhibited superhydrophobic (water contact angle 157.7°) and superoleophilic (oily/organic solvent contact angle 0° properties. Owing to the highly porous structure, superhydrophobic property, chemical and mechanical stability, the ME/PDA/DT sponge exhibited outstanding absorbency properties of oily organic solvents including fast absorption kinetics, high absorption capacity, and easy reusability. Also, the ME/PDA/DT sponge could be used for one-line continuous organic solvent/water separation. More interestingly, the ME/PDA/DT sponge demonstrated improved flame-retardant property as compared to the intrinsic flame-retardant nature of the raw melamine sponge. Consequently, the risk of fire and explosion was expected to reduce when the fabricated sponge was used as an absorbent for flammable oils and organic compounds. The ease of the one-step superhydrophobic/superoleophilic modification and the promising feature of the obtained materials exhibit great potential for application in oils/organic solvents clean-up.

  12. Hydrogen-bromine fuel cell advance component development

    Science.gov (United States)

    Charleston, Joann; Reed, James

    1988-01-01

    Advanced cell component development is performed by NASA Lewis to achieve improved performance and longer life for the hydrogen-bromine fuel cells system. The state-of-the-art hydrogen-bromine system utilizes the solid polymer electrolyte (SPE) technology, similar to the SPE technology developed for the hydrogen-oxygen fuel cell system. These studies are directed at exploring the potential for this system by assessing and evaluating various types of materials for cell parts and electrode materials for Bromine-hydrogen bromine environment and fabricating experimental membrane/electrode-catalysts by chemical deposition.

  13. Horizontal and vertical structure of reactive bromine events probed by bromine monoxide MAX-DOAS

    Directory of Open Access Journals (Sweden)

    W. R. Simpson

    2017-08-01

    Full Text Available Heterogeneous photochemistry converts bromide (Br− to reactive bromine species (Br atoms and bromine monoxide, BrO that dominate Arctic springtime chemistry. This phenomenon has many impacts such as boundary-layer ozone depletion, mercury oxidation and deposition, and modification of the fate of hydrocarbon species. To study environmental controls on reactive bromine events, the BRomine, Ozone, and Mercury EXperiment (BROMEX was carried out from early March to mid-April 2012 near Barrow (Utqiaġvik, Alaska. We measured horizontal and vertical gradients in BrO with multiple-axis differential optical absorption spectroscopy (MAX-DOAS instrumentation at three sites, two mobile and one fixed. During the campaign, a large crack in the sea ice (an open lead formed pushing one instrument package ∼ 250 km downwind from Barrow (Utqiaġvik. Convection associated with the open lead converted the BrO vertical structure from a surface-based event to a lofted event downwind of the lead influence. The column abundance of BrO downwind of the re-freezing lead was comparable to upwind amounts, indicating direct reactions on frost flowers or open seawater was not a major reactive bromine source. When these three sites were separated by ∼ 30 km length scales of unbroken sea ice, the BrO amount and vertical distributions were highly correlated for most of the time, indicating the horizontal length scales of BrO events were typically larger than ∼ 30 km in the absence of sea ice features. Although BrO amount and vertical distribution were similar between sites most of the time, rapid changes in BrO with edges significantly smaller than this ∼ 30 km length scale episodically transported between the sites, indicating BrO events were large but with sharp edge contrasts. BrO was often found in shallow layers that recycled reactive bromine via heterogeneous reactions on snowpack. Episodically, these surface-based events propagated aloft when

  14. Unsteady Flame Embedding

    KAUST Repository

    El-Asrag, Hossam A.

    2011-01-01

    Direct simulation of all the length and time scales relevant to practical combustion processes is computationally prohibitive. When combustion processes are driven by reaction and transport phenomena occurring at the unresolved scales of a numerical simulation, one must introduce a dynamic subgrid model that accounts for the multiscale nature of the problem using information available on a resolvable grid. Here, we discuss a model that captures unsteady flow-flame interactions- including extinction, re-ignition, and history effects-via embedded simulations at the subgrid level. The model efficiently accounts for subgrid flame structure and incorporates detailed chemistry and transport, allowing more accurate prediction of the stretch effect and the heat release. In this chapter we first review the work done in the past thirty years to develop the flame embedding concept. Next we present a formulation for the same concept that is compatible with Large Eddy Simulation in the flamelet regimes. The unsteady flame embedding approach (UFE) treats the flame as an ensemble of locally one-dimensional flames, similar to the flamelet approach. However, a set of elemental one-dimensional flames is used to describe the turbulent flame structure directly at the subgrid level. The calculations employ a one-dimensional unsteady flame model that incorporates unsteady strain rate, curvature, and mixture boundary conditions imposed by the resolved scales. The model is used for closure of the subgrid terms in the context of large eddy simulation. Direct numerical simulation (DNS) data from a flame-vortex interaction problem is used for comparison. © Springer Science+Business Media B.V. 2011.

  15. Trophic transfer of naturally produced brominated aromatic compounds in a Baltic Sea food chain.

    Science.gov (United States)

    Dahlgren, Elin; Lindqvist, Dennis; Dahlgren, Henrik; Asplund, Lillemor; Lehtilä, Kari

    2016-02-01

    Brominated aromatic compounds (BACs) are widely distributed in the marine environment. Some of these compounds are highly toxic, such as certain hydroxylated polybrominated diphenyl ethers (OH-PBDEs). In addition to anthropogenic emissions through use of BACs as e.g. flame retardants, BACs are natural products formed by marine organisms such as algae, sponges, and cyanobacteria. Little is known of the transfer of BACs from natural producers and further up in the trophic food chain. In this study it was observed that total sum of methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and OH-PBDEs increased in concentration from the filamentous red alga Ceramium tenuicorne, via Gammarus sp. and three-spined stickleback (Gasterosteus aculeatus) to perch (Perca fluviatilis). The MeO-PBDEs, which were expected to bioaccumulate, increased in concentration accordingly up to perch, where the levels suddenly dropped dramatically. The opposite pattern was observed for OH-PBDEs, where the concentration exhibited a general trend of decline up the food web, but increased in perch, indicating metabolic demethylation of MeO-PBDEs. Debromination was also indicated to occur when progressing through the food chain resulting in high levels of tetra-brominated MeO-PBDE and OH-PBDE congeners in fish, while some penta- and hexa-brominated congeners were observed to be the dominant products in the alga. As it has been shown that OH-PBDEs are potent disruptors of oxidative phosphorylation and that mixtures of different congener may act synergistically in terms of this toxic mode of action, the high levels of OH-PBDEs detected in perch in this study warrants further investigation into potential effects of these compounds on Baltic wildlife, and monitoring of their levels. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Hydrogen-enriched non-premixed jet flames : analysis of the flame surface, flame normal, flame index and Wobbe index

    NARCIS (Netherlands)

    Ranga Dinesh, K.K.J.; Jiang, X.; Oijen, van J.A.

    2014-01-01

    A non-premixed impinging jet flame is studied using three-dimensional direct numerical simulation with detailed chemical kinetics in order to investigate the influence of fuel variability on flame surface, flame normal, flame index and Wobbe index for hydrogen-enriched combustion. Analyses indicate

  17. Flame structure of methane inverse diffusion flame

    KAUST Repository

    Elbaz, Ayman M.; Roberts, William L.

    2014-01-01

    This paper presents high speed images of OH-PLIF at 10. kHz simultaneously with 2D PIV (particle image velocimetry) measurements collected along the entire length of an inverse diffusion flame with circumferentially arranged methane fuel jets. For a

  18. Treatment of sewage from iodo-bromine industrial plants from the second group cations using carboxyl cationnites

    International Nuclear Information System (INIS)

    Kononova, G.N.; Dolbysheva, A.G.; Ksenzenko, V.I.; Ryazantseva, Zh.I.

    1977-01-01

    Effectiveness has been shown of purifying sewage from iodo-bromine plants from the second Group cations on a carboxyl cationite KB-4P. For strongly mineralized waters as industrial waters from iodo-bromine plants, the selectivity decreases in the series: Ca 2+ > Sr 2+ > Mg 2+ . It has been shown that the determining stage is an outside diffusion. SH nitric acid has been used for regeneration of cationite. The second Group cations are washed off with nitric acid simultaneously and at a high rate. Strontium can be separated from the eluate obtained by the halurgical method

  19. Uranium hexafluoride and uranyl nitrate. Ionometric determination of bromine

    International Nuclear Information System (INIS)

    Anon.

    Bromine was determined in uranium hexafluoride. The method is suitable for determining 2 to 20 ppm with respect to uranium. Bromides are oxidized by potassium permanganate to give bromine which is extracted into carbon tetrachloride, reduced by ascorbic acid and determined by ionometry [fr

  20. Brominated methanes as photoresponsive molecular storage of elemental Br2.

    Science.gov (United States)

    Kawakami, Kazumitsu; Tsuda, Akihiko

    2012-10-01

    The photochemical generation of elemental Br(2) from brominated methanes is reported. Br(2) was generated by the vaporization of carbon oxides and HBr through oxidative photodecomposition of brominated methanes under a 20 W low-pressure mercury lamp, wherein the amount and situations of Br(2) generation were photochemically controllable. Liquid CH(2)Br(2) can be used not only as an organic solvent but also for the photoresponsive molecular storage of Br(2), which is of great technical benefit in a variety of organic syntheses and in materials science. By taking advantage of the in situ generation of Br(2) from the organic solvent itself, many organobromine compounds were synthesized in high practical yields with or without the addition of a catalyst. Herein, Br(2) that was generated by the photodecomposition of CH(2)Br(2) retained its reactivity in solution to undergo essentially the same reactions as those that were carried out with solutions of Br(2) dissolved in CH(2)Br(2) that were prepared without photoirradiation. Furthermore, HBr, which was generated during the course of the photodecomposition of CH(2)Br(2), was also available for the substitution of the OH group for the Br group and for the preparation of the HBr salts of amines. Furthermore, the photochemical generation of Br(2) from CH(2)Br(2) was available for the area-selective photochemical bleaching of natural colored plants, such as red rose petals, wherein Br(2) that was generated photochemically from CH(2)Br(2) was painted onto the petal to cause radical oxidations of the chromophoric anthocyanin molecules. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Isomer-specific combustion chemistry in allene and propyne flames

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Nils; Miller, James A. [Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551 (United States); Westmoreland, Phillip R. [Department of Chem. Engineering, University of Massachusetts, Amherst, MA 01003 (United States); Kasper, Tina [Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551 (United States); Department of Chemistry, Bielefeld University, D-33615 Bielefeld (Germany); Kohse-Hoeinghaus, Katharina [Department of Chemistry, Bielefeld University, D-33615 Bielefeld (Germany); Wang, Juan; Cool, Terrill A. [School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853 (United States)

    2009-11-15

    A combined experimental and modeling study is performed to clarify the isomer-specific combustion chemistry in flames fueled by the C{sub 3}H{sub 4} isomers allene and propyne. To this end, mole fraction profiles of several flame species in stoichiometric allene (propyne)/O{sub 2}/Ar flames are analyzed by means of a chemical kinetic model. The premixed flames are stabilized on a flat-flame burner under a reduced pressure of 25 Torr (=33.3 mbar). Quantitative species profiles are determined by flame-sampling molecular-beam mass spectrometry, and the isomer-specific flame compositions are unraveled by employing photoionization with tunable vacuum-ultraviolet synchrotron radiation. The temperature profiles are measured by OH laser-induced fluorescence. Experimental and modeled mole fraction profiles of selected flame species are discussed with respect to the isomer-specific combustion chemistry in both flames. The emphasis is put on main reaction pathways of fuel consumption, of allene and propyne isomerization, and of isomer-specific formation of C{sub 6} aromatic species. The present model includes the latest theoretical rate coefficients for reactions on a C{sub 3}H{sub 5} potential [J.A. Miller, J.P. Senosiain, S.J. Klippenstein, Y. Georgievskii, J. Phys. Chem. A 112 (2008) 9429-9438] and for the propargyl recombination reactions [Y. Georgievskii, S.J. Klippenstein, J.A. Miller, Phys. Chem. Chem. Phys. 9 (2007) 4259-4268]. Larger peak mole fractions of propargyl, allyl, and benzene are observed in the allene flame than in the propyne flame. In these flames virtually all of the benzene is formed by the propargyl recombination reaction. (author)

  2. Unsteady Flame Embedding

    KAUST Repository

    El-Asrag, Hossam A.; Ghoniem, Ahmed F.

    2011-01-01

    simulation, one must introduce a dynamic subgrid model that accounts for the multiscale nature of the problem using information available on a resolvable grid. Here, we discuss a model that captures unsteady flow-flame interactions- including extinction, re

  3. Flame synthesis of zinc oxide nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Merchan-Merchan, Wilson, E-mail: wmerchan-merchan@ou.edu [School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019 (United States); Farahani, Moien Farmahini [School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019 (United States)

    2013-02-01

    Highlights: Black-Right-Pointing-Pointer We report a single-step flame method for the synthesis of Zn oxide nanocrystals. Black-Right-Pointing-Pointer Diverse flame positions lead to a variation of Zn oxide nanocrystal growth. Black-Right-Pointing-Pointer The synthesized crystals have polyhedral, pipet- and needle-like shape. Black-Right-Pointing-Pointer High length-to-diameter aspect-ratio crystals appear in a higher temperature flame. Black-Right-Pointing-Pointer The crystal growth mechanism corresponds to vapor-to-solid conversion. - Abstract: Distinctive zinc oxide (ZnO) nanocrystals were synthesized on the surface of Zn probes using a counter-flow flame medium formed by methane/acetylene and oxygen-enriched air streams. The source material, a zinc wire with a purity of {approx}99.99% and diameter of 1 mm, was introduced through a sleeve into the oxygen rich region of the flame. The position of the probe/sleeve was varied within the flame medium resulting in growth variation of ZnO nanocrystals on the surface of the probe. The shape and structural parameters of the grown crystals strongly depend on the flame position. Structural variations of the synthesized crystals include single-crystalline ZnO nanorods and microprisms (ZMPs) (the ZMPs have less than a few micrometers in length and several hundred nanometers in cross section) with a large number of facets and complex axial symmetry with a nanorod protruding from their tips. The protruding rods are less than 100 nm in diameter and lengths are less than 1 {mu}m. The protruding nanorods can be elongated several times by increasing the residence time of the probe/sleeve inside the oxygen-rich flame or by varying the flame position. At different flame heights, nanorods having higher length-to-diameter aspect-ratio can be synthesized. A lattice spacing of {approx}0.26 nm was measured for the synthesized nanorods, which can be closely correlated with the (0 0 2) interplanar spacing of hexagonal ZnO (Wurtzite) cells

  4. Characterization of Some Real Mixed Plastics from WEEE: A Focus on Chlorine and Bromine Determination by Different Analytical Methods

    Directory of Open Access Journals (Sweden)

    Beatrice Beccagutti

    2016-10-01

    Full Text Available Bromine and chlorine are almost ubiquitous in waste of electrical and electronic equipment (WEEE and the knowledge of their content in the plastic fraction is an essential step for proper end of life management. The aim of this study is to compare the following analytical methods: energy dispersive X-ray fluorescence spectroscopy (ED-XRF, ion chromatography (IC, ion-selective electrodes (ISEs, and elemental analysis for the quantitative determination of chlorine and bromine in four real samples taken from different WEEE treatment plants, identifying the best analytical technique for waste management workers. Home-made plastic standard materials with known concentrations of chlorine or bromine have been used for calibration of ED-XRF and to test the techniques before the sample analysis. Results showed that IC and ISEs, based upon dissolution of the products of the sample combustion, have not always achieved a quantitative absorption of the analytes in the basic solutions and that bromine could be underestimated since several oxidation states occur after combustion. Elemental analysis designed for chlorine determination is subjected to strong interference from bromine and required frequent regeneration and recalibration of the measurement cell. The most reliable method seemed to be the non-destructive ED-XRF. Calibration with home-made standards, having a similar plastic matrix of the samples, enabled us to carry out quantitative determinations, which have been revealed to be satisfactorily accurate and precise. In all the analyzed samples a total concentration of chlorine and/or bromine between 0.6 and 4 w/w% was detected, compromising the feasibility of a mechanical recycling and suggesting the exploration of an alternative route for managing these plastic wastes.

  5. Direct Vapor-Phase Bromination of Multiwall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Ilya Mazov

    2012-01-01

    Full Text Available We present the simple procedure of the vapor-phase bromination of multiwall carbon nanotubes (MWNTs at moderate temperatures. MWNTs with average diameter 9±3 nm were treated with Br2 vapors at 250°C to produce Br-functionalized product. Transmission electron microscopy analysis was used to prove low damage of MWNT walls during bromination. X-ray photoelectron spectroscopy (XPS and differential thermal analysis (DTA were used to investigate chemical composition of the surface of initial and brominated nanotubes. The experimental results show that the structure of MWNTs is not affected by the bromination process and the total amount of Br-containing surface functions reaches 2.5 wt. %. Electrophysical properties of initial and brominated MWNTs were investigated showing decrease of conductivity for functionalized sample. Possible mechanism of the vapor-phase bromination via surface defects and oxygen-containing functional groups was proposed according to data obtained. Additional experiments with bromination of annealed low-defected MWNTs were performed giving Br content a low as 0.75 wt. % proving this hypothesis.

  6. Flame retardants: Dust - And not food - Might be the risk.

    Science.gov (United States)

    de Boer, J; Ballesteros-Gómez, A; Leslie, H A; Brandsma, S H; Leonards, P E G

    2016-05-01

    Flame retardants (FRs) are used to delay ignition of materials such as furniture and electric and electronic instruments. Many FRs are persistent and end up in the environment. Environmental studies on flame retardants (FRs) took off in the late 1990s. Polybrominated diphenylethers (PBDEs) appeared to be bioaccumulative and were found in many organisms all over the world. When PBDEs were banned or their production voluntarily terminated, alternatives appeared on the market that often had similar properties or were of more concern due to their toxicity such as halogenated phosphorus-based FRs. Here we show that in spite of the ban on PBDEs more brominated FRs are being produced, an increasing number of other FRs is being applied and FR levels in our homes are much higher than in the outdoor environment. While nowadays we live in better isolated houses and sit in front of the computer or television, on flame retarded upholstery, we are at risk due to the toxic effects of a suite of FRs. The high exposure to these substances indoors calls for better risk assessments that include mixture effects. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Hydrogen-Bromine Flow Battery: Hydrogen Bromine Flow Batteries for Grid Scale Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-10-01

    GRIDS Project: LBNL is designing a flow battery for grid storage that relies on a hydrogen-bromine chemistry which could be more efficient, last longer and cost less than today’s lead-acid batteries. Flow batteries are fundamentally different from traditional lead-acid batteries because the chemical reactants that provide their energy are stored in external tanks instead of inside the battery. A flow battery can provide more energy because all that is required to increase its storage capacity is to increase the size of the external tanks. The hydrogen-bromine reactants used by LBNL in its flow battery are inexpensive, long lasting, and provide power quickly. The cost of the design could be well below $100 per kilowatt hour, which would rival conventional grid-scale battery technologies.

  8. Chlorine and bromine contents in tobacco and tobacco smoke

    International Nuclear Information System (INIS)

    Haesaenen, E.; Manninen, P.K.G.; Himberg, K.; Vaeaetaeinen, V.

    1990-01-01

    The chlorine and bromine contents in tobacco and tobacco smoke in both the particulate and gaseous phases were studied by neutron activation analysis. Eleven popular brands of western filter cigarettes were tested. Methyl chloride and methyl bromide concentrations were measured in the gaseous phase in two leading brands in Finland. The results suggest that the mainstream smoke from one cigarette conveys into the lungs about 150 μg chlorine and about 5 μg bromine. Probably most of the chlorine and bromine is in the form of organic compounds and the main components are methyl chloride and methyl bromide. (author) 14 refs.; 1 tab

  9. Strained flamelets for turbulent premixed flames II: Laboratory flame results

    Energy Technology Data Exchange (ETDEWEB)

    Kolla, H.; Swaminathan, N. [Department of Engineering, Cambridge University, Cambridge CB2 1PZ (United Kingdom)

    2010-07-15

    The predictive ability of strained flamelets model for turbulent premixed flames is assessed using Reynolds Averaged Navier Stokes (RANS) calculations of laboratory flames covering a wide range of conditions. Reactant-to-product (RtP) opposed flow laminar flames parametrised using the scalar dissipation rate of reaction progress variable are used as strained flamelets. Two turbulent flames: a rod stabilised V-flame studied by Robin et al. [Combust. Flame 153 (2008) 288-315] and a set of pilot stabilised Bunsen flames studied by Chen et al. [Combust. Flame 107 (1996) 223-244] are calculated using a single set of model parameters. The V-flame corresponds to the corrugated flamelets regime. The strained flamelet model and an unstrained flamelet model yield similar predictions which are in good agreement with experimental measurements for this flame. On the other hand, for the Bunsen flames which are in the thin reaction zones regime, the unstrained flamelet model predicts a smaller flame brush compared to experiment. The predictions of the strained flamelets model allowing for fluid-dynamics stretch induced attenuation of the chemical reaction are in good agreement with the experimental data. This model predictions of major and minor species are also in good agreement with experimental data. The results demonstrate that the strained flamelets model using the scalar dissipation rate can be used across the combustion regimes. (author)

  10. Flame retardant synergism between molybdenum and halogen-containing compounds in unsaturated polyesters. [Smoke suppression

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, G.A.; Parker, L.E.; Marshall, P.J.

    1978-01-01

    Oxygen index results for a series of unsaturated polyesters, containing molybdenum oxide and various halogenated compounds, have provided definite evidence for some form of flame retardant synergistic effect between molybdenum and halogen. With the halogenated compounds used, the magnitude of the effect was greater in the presence of bromine but was dependent on the type of compound. When dibromoneopentyl glycol was used as the bromine source, the synergistic effect exhibited by molybdenum oxide was comparable to that shown by antimony oxide. Since molybdenum oxide also acts as a smoke suppressant, it could offer a useful alternative to antimony oxide particularly in the light of probable changes in standards and regulatory control regarding smoke emission. 4 figures, 2 tables.

  11. Mechanochemical conversion of brominated POPs into useful oxybromides: a greener approach

    Science.gov (United States)

    Cagnetta, Giovanni; Liu, Han; Zhang, Kunlun; Huang, Jun; Wang, Bin; Deng, Shubo; Wang, Yujue; Yu, Gang

    2016-06-01

    Brominated organic pollutants are considered of great concern for their adverse effect on human health and the environment, so an increasing number of such compounds are being classified as persistent organic pollutants (POPs). Mechanochemical destruction is a promising technology for POPs safe disposal because it can achieve their complete carbonization by solvent-free high energy ball milling at room temperature. However, a large amount of co-milling reagent usually is necessary, so a considerable volume of residue is produced. In the present study a different approach to POPs mechanochemical destruction is proposed. Employing stoichiometric quantities of Bi2O3 or La2O3 as co-milling reagent, brominated POPs are selectively and completely converted into their corresponding oxybromides (i.e. BiOBr and LaOBr), which possess very peculiar properties and can be used for some actual and many more potential applications. In this way, bromine is beneficially reused in the final product, while POPs carbon skeleton is safely destroyed to amorphous carbon. Moreover, mechanochemical destruction is employed in a greener and more sustainable manner.

  12. Flaming on YouTube

    NARCIS (Netherlands)

    Moor, Peter J.; Heuvelman, A.; Verleur, R.

    2010-01-01

    In this explorative study, flaming on YouTube was studied using surveys of YouTube users. Flaming is defined as displaying hostility by insulting, swearing or using otherwise offensive language. Three general conclusions were drawn. First, although many users said that they themselves do not flame,

  13. Tetrameric DABCO™-Bromine: an Efficient and Versatile Reagent ...

    African Journals Online (AJOL)

    NJD

    Reagent for Bromination of Various Organic Compounds. Majid M. Heravi,a* ... aDepartment of Chemistry, School of Sciences, Azzahra University, Vanak, Tehran, Iran. bChemistry ... Synthesis of "-bromo ketones and nitriles has also been ...

  14. Bromine pretreated chitosan for adsorption of lead (II) from water

    Indian Academy of Sciences (India)

    isotherm and maximum sorption capacity of 30% bromine pretreated chitosan sorbent was 1·755 g/kg with 85–. 90% lead .... C by applying Lagergren first ... Lead (II) ions concentrations were determined by using an .... following equation.

  15. The bromine content of some Dutch crops and fruits

    International Nuclear Information System (INIS)

    Admiraal, P.; Kok, H.A.; Das, H.A.; Hoede, D.; Zonderhuis, J.

    1975-09-01

    The natural bromine-content of Dutch potatoes, vegetables and fruits was determined by instrumental neutron activation analysis. Results are given for 348 samples divided over 20 crops and fruits. The data are compared to values published in the literature

  16. Numerical modelling of ion transport in flames

    KAUST Repository

    Han, Jie

    2015-10-20

    This paper presents a modelling framework to compute the diffusivity and mobility of ions in flames. The (n, 6, 4) interaction potential is adopted to model collisions between neutral and charged species. All required parameters in the potential are related to the polarizability of the species pair via semi-empirical formulas, which are derived using the most recently published data or best estimates. The resulting framework permits computation of the transport coefficients of any ion found in a hydrocarbon flame. The accuracy of the proposed method is evaluated by comparing its predictions with experimental data on the mobility of selected ions in single-component neutral gases. Based on this analysis, the value of a model constant available in the literature is modified in order to improve the model\\'s predictions. The newly determined ion transport coefficients are used as part of a previously developed numerical approach to compute the distribution of charged species in a freely propagating premixed lean CH4/O2 flame. Since a significant scatter of polarizability data exists in the literature, the effects of changes in polarizability on ion transport properties and the spatial distribution of ions in flames are explored. Our analysis shows that changes in polarizability propagate with decreasing effect from binary transport coefficients to species number densities. We conclude that the chosen polarizability value has a limited effect on the ion distribution in freely propagating flames. We expect that the modelling framework proposed here will benefit future efforts in modelling the effect of external voltages on flames. Supplemental data for this article can be accessed at http://dx.doi.org/10.1080/13647830.2015.1090018. © 2015 Taylor & Francis.

  17. BROMINATED-FLAME RETARDANTS (BFRS) IN CATS – POSSIBLE LINKAGE TO FELINE HYPERTHYROIDISM?

    Science.gov (United States)

    Coincident with global introduction of BFRs into house¬hold consumer products nearly 30 years ago, hyperthyroidism in cats has increased considerably. The etiopathogenesis of feline hyperthyroidism remains unknown. We hypothesized that increasing exposure of pet cats to BFRs such...

  18. The first exposure assessment of legacy and unrestricted brominated flame retardants in predatory birds of Pakistan

    DEFF Research Database (Denmark)

    Abbasi, Naeem Akhtar; Eulaers, Igor; Jaspers, Veerle Leontina Bernard

    2017-01-01

    The exposure to legacy polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs) and unrestricted 1,2-bis (2,4,6-tribromophenoxy) ethane (BTBPE), bis (2-ethylhexyl)-2,3,4,5-tetrabromophthalate (BEH-TEBP) and 2-ethylhexyl-2,3,4,5-tetrabromo-benzoate (EH-TBB) was examined in tail fea...

  19. Stratified turbulent Bunsen flames : flame surface analysis and flame surface density modelling

    NARCIS (Netherlands)

    Ramaekers, W.J.S.; Oijen, van J.A.; Goey, de L.P.H.

    2012-01-01

    In this paper it is investigated whether the Flame Surface Density (FSD) model, developed for turbulent premixed combustion, is also applicable to stratified flames. Direct Numerical Simulations (DNS) of turbulent stratified Bunsen flames have been carried out, using the Flamelet Generated Manifold

  20. Direct Flame Impingement

    Energy Technology Data Exchange (ETDEWEB)

    None

    2005-09-01

    During the DFI process, high velocity flame jets impinge upon the material being heated, creating a high heat transfer rate. As a result, refractory walls and exhaust gases are cooler, which increases thermal efficiency and lowers NOx emissions. Because the jet nozzles are located a few inches from the load, furnace size can be reduced significantly.

  1. Flame visualization in power stations

    Energy Technology Data Exchange (ETDEWEB)

    Hulshof, H J.M.; Thus, A W; Verhage, A J.L. [KEMA - Fossil Power Plants, Arnhem (Netherlands)

    1993-01-01

    The shapes and temperature of flames in power stations, fired with powder coal and gas, have been measured optically. Spectral information in the visible and near infrared is used. Coal flames are visualized in the blue part of the spectrum, natural gas flames are viewed in the light of CH-emission. Temperatures of flames are derived from the best fit of the Planck-curve to the thermal radiation spectrum of coal and char, or to that of soot in the case of gas flames. A measuring method for the velocity distribution inside a gas flame is presented, employing pulsed alkali salt injection. It has been tested on a 100 kW natural gas flame. 3 refs., 9 figs.

  2. Flame kernel generation and propagation in turbulent partially premixed hydrocarbon jet

    KAUST Repository

    Mansour, Mohy S.

    2014-04-23

    Flame development, propagation, stability, combustion efficiency, pollution formation, and overall system efficiency are affected by the early stage of flame generation defined as flame kernel. Studying the effects of turbulence and chemistry on the flame kernel propagation is the main aim of this work for natural gas (NG) and liquid petroleum gas (LPG). In addition the minimum ignition laser energy (MILE) has been investigated for both fuels. Moreover, the flame stability maps for both fuels are also investigated and analyzed. The flame kernels are generated using Nd:YAG pulsed laser and propagated in a partially premixed turbulent jet. The flow field is measured using 2-D PIV technique. Five cases have been selected for each fuel covering different values of Reynolds number within a range of 6100-14400, at a mean equivalence ratio of 2 and a certain level of partial premixing. The MILE increases by increasing the equivalence ratio. Near stoichiometric the energy density is independent on the jet velocity while in rich conditions it increases by increasing the jet velocity. The stability curves show four distinct regions as lifted, attached, blowout, and a fourth region either an attached flame if ignition occurs near the nozzle or lifted if ignition occurs downstream. LPG flames are more stable than NG flames. This is consistent with the higher values of the laminar flame speed of LPG. The flame kernel propagation speed is affected by both turbulence and chemistry. However, at low turbulence level chemistry effects are more pronounced while at high turbulence level the turbulence becomes dominant. LPG flame kernels propagate faster than those for NG flame. In addition, flame kernel extinguished faster in LPG fuel as compared to NG fuel. The propagation speed is likely to be consistent with the local mean equivalence ratio and its corresponding laminar flame speed. Copyright © Taylor & Francis Group, LLC.

  3. Alternative Flame Retardant, 2,4,6-Tris(2,4,6-tribromophenoxy)-1,3,5-triazine, in an E-waste Recycling Facility and House Dust in North America.

    Science.gov (United States)

    Guo, Jiehong; Stubbings, William A; Romanak, Kevin; Nguyen, Linh V; Jantunen, Liisa; Melymuk, Lisa; Arrandale, Victoria; Diamond, Miriam L; Venier, Marta

    2018-03-20

    A high molecular weight compound, 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ), was detected during the analysis of brominated flame retardants in dust samples collected from an electrical and electronic waste (e-waste) recycling facility in Ontario, Canada. Gas chromatography coupled with both high-resolution and low-resolution mass spectrometry (MS) was used to determine TTBP-TAZ's chemical structure and concentrations. To date, TTBP-TAZ has only been detected in plastic casings of electrical and electronic equipment and house dust from The Netherlands. Here we report on the concentrations of TTBP-TAZ in selected samples from North America: e-waste dust ( n = 7) and air ( n = 4), residential dust ( n = 30), and selected outdoor air ( n = 146), precipitation ( n = 19), sediment ( n = 11) and water ( n = 2) samples from the Great Lakes environment. TTBP-TAZ was detected in all the e-waste dust and air samples, and in 70% of residential dust samples. The median concentrations of TTBP-TAZ in these three types of samples were 5540 ng/g, 5.75 ng/m 3 and 6.76 ng/g, respectively. The flame retardants 2,4,6-tribromophenol, tris(2,3-dibromopropyl) isocyanurate, and 3,3',5,5'-tetrabromobisphenol A bis(2,3-dibromopropyl) ether, BDE-47 and BDE-209 were also measured for comparison. None of these other flame retardants concentrations was significantly correlated with those of TTBP-TAZ in any of the sample types suggesting different sources. TTBP-TAZ was not detected in any of the outdoor environmental samples, which may relate to its application history and physicochemical properties. This is the first report of TTBP-TAZ in North America.

  4. A new ultrasonic-assisted cloud-point-extraction procedure for pre-concentration and determination of ultra-trace levels of copper in selected beverages and foods by flame atomic absorption spectrometry.

    Science.gov (United States)

    Altunay, Nail; Gürkan, Ramazan; Orhan, Ulaş

    2015-01-01

    A new ultrasonic-assisted cloud-point-extraction (UA-CPE) method was developed for the pre-concentration of Cu(II) in selected beverage and food samples prior to flame atomic absorption spectrometric (FAAS) analysis. For this purpose, Safranin T was used as an ion-pairing reagent based on charge transfer in the presence of oxalate as the primary chelating agent at pH 10. Non-ionic surfactant, poly(ethyleneglycol-mono-p-nonylphenylether) (PONPE 7.5) was used as an extracting agent in the presence of NH4Cl as the salting out agent. The variables affecting UA-CPE efficiency were optimised in detail. The linear range for Cu(II) at pH 10 was 0.02-70 µg l(-)(1) with a very low detection limit of 6.10 ng l(-)(1), while the linear range for Cu(I) at pH 8.5 was 0.08-125 µg l(-)(1) with a detection limit of 24.4 ng l(-)(1). The relative standard deviation (RSD %) was in the range of 2.15-4.80% (n = 5). The method was successfully applied to the quantification of Cu(II), Cu(I) and total Cu in selected beverage and food samples. The accuracy of the developed method was demonstrated by the analysis of two standard reference materials (SRMs) as well as recoveries of spiked samples.

  5. Cobalt catalyzed peroxymonosulfate oxidation of tetrabromobisphenol A: Kinetics, reaction pathways, and formation of brominated by-products

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Yuefei [Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095 (China); Kong, Deyang [Nanjing Institute of Environmental Science, Ministry of Environmental Protection of PRC, Nanjing 210042 (China); Lu, Junhe, E-mail: jhlu@njau.edu.cn [Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095 (China); Jin, Hao; Kang, Fuxing; Yin, Xiaoming; Zhou, Quansuo [Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095 (China)

    2016-08-05

    Highlights: • Cobalt catalyzed peroxymonosulfate oxidation of tetrabromobisphenol A. • Phenolic moiety was the reactive site for sulfate radical attack. • Pathways include β-scission, oxidation, debromination and coupling reactions. • Brominated disinfection by-products were found during TBBPA degradation. • Humic acid inhibited TBBPA degradation but promoted DBPs formation. - Abstract: Degradation of tetrabromobisphenol A (TBBPA), a flame retardant widely spread in the environment, in Co(II) catalyzed peroxymonosulfate (PMS) oxidation process was systematically explored. The second-order-rate constant for reaction of sulfate radical (SO{sub 4}{sup ·−}) with TBBPA was determined to be 5.27 × 10{sup 10} M{sup −1} s{sup −1}. Apparently, degradation of TBBPA showed first-order kinetics to the concentrations of both Co(II) and PMS. The presence of humic acid (HA) and bicarbonate inhibited TBBPA degradation, most likely due to their competition for SO{sub 4}{sup ·−}. Degradation of TBBPA was initiated by an electron abstraction from one of the phenolic rings. Detailed transformation pathways were proposed, including β-scission of isopropyl bridge, phenolic ring oxidation, debromination and coupling reactions. Further oxidative degradation of intermediates in Co(II)/PMS process yielded brominated disinfection by-products (Br-DBPs) such as bromoform and brominated acetic acids. Evolution profile of Br-DBPs showed an initially increasing and then decreasing pattern with maximum concentrations occurring around 6–10 h. The presence of HA enhanced the formation of Br-DBPs significantly. These findings reveal potentially important, but previously unrecognized, formation of Br-DBPs during sulfate radical-based oxidation of bromide-containing organic compounds that may pose toxicological risks to human health.

  6. An efficient and fast analytical procedure for the bromine determination in waste electrical and electronic equipment plastics.

    Science.gov (United States)

    Taurino, R; Cannio, M; Mafredini, T; Pozzi, P

    2014-01-01

    In this study, X-ray fluorescence (XRF) spectroscopy was used, in combination with micro-Raman spectroscopy, for a fast determination of bromine concentration and then of brominated flame retardants (BFRs) compounds in waste electrical and electronic equipments. Different samples from different recycling industries were characterized to evaluate the sorting performances of treatment companies. This investigation must be considered of prime research interest since the impact of BFRs on the environment and their potential risk on human health is an actual concern. Indeed, the new European Restriction of Hazardous Substances Directive (RoHS 2011/65/EU) demands that plastics with BFRs concentration above 0.1%, being potential health hazards, are identified and eliminated from the recycling process. Our results show the capability and the potential of Raman spectroscopy, together with XRF analysis, as effective tools for the rapid detection of BFRs in plastic materials. In particular, the use of these two techniques in combination can be considered as a promising method suitable for quality control applications in the recycling industry.

  7. Antimony: a flame fighter

    Science.gov (United States)

    Wintzer, Niki E.; Guberman, David E.

    2015-01-01

    Antimony is a brittle, silvery-white semimetal that conducts heat poorly. The chemical compound antimony trioxide (Sb2O3) is widely used in plastics, rubbers, paints, and textiles, including industrial safety suits and some children’s clothing, to make them resistant to the spread of flames. Also, sodium antimonate (NaSbO3) is used during manufacturing of high-quality glass, which is found in cellular phones.

  8. Magnetically enhanced triode etching of large area silicon membranes in a molecular bromine plasma

    International Nuclear Information System (INIS)

    Wolfe, J.C.; Sen, S.; Pendharkar, S.V.; Mauger, P.; Shimkunas, A.R.

    1992-01-01

    The optimization of a process for etching 125 mm silicon membranes formed on 150 mm wafers and bonded to Pyrex rings is discussed. A magnetically enhanced triode etching system was designed to provide an intense, remote plasma surrounding the membrane while, at the same time, suppressing the discharge over the membrane itself. For the optimized molecular bromine process, the silicon etch rate is 40 nm/min and the selectivity relative to SiO 2 is 160:1. 14 refs., 6 figs

  9. Fate of higher brominated PBDEs in lactating cows.

    Science.gov (United States)

    Kierkegaard, Amelie; Asplund, Lillemor; de Wit, Cynthia A; McLachlan, Michael S; Thomas, Gareth O; Sweetman, Andrew J; Jones, Kevin C

    2007-01-15

    Dietary intake studies of lower brominated diphenyl ethers (BDEs) have shown that fish and animal products are important vectors of human exposure, but almost no data exist for higher brominated BDEs. Therefore, the fate of hepta- to decaBDEs was studied in lactating cows exposed to a naturally contaminated diet by analyzing feed, feces, and milk samples from a previous mass balance study of PCB. Tissue distribution was studied in one cow slaughtered after the experiment. BDE-209 was the dominant congener in feed, organs, adipose tissues, and feces, but not in milk. In contrast to PCBs and lower brominated BDEs, concentrations of hepta- to decaBDEs in adipose tissue were 9-80 times higher than in milk fat and the difference increased with degree of bromination/log K(OW). The congener profiles in adipose tissue and feed differed; BDE-207, BDE-196, BDE-197, and BDE-182 accumulated to a surprisingly greater extent in the fat compared to their isomers, suggesting metabolic debromination of BDE-209 to these BDEs. The results indicate that meat rather than dairy product consumption may be an important human exposure route to higher brominated BDEs.

  10. Aryl- and alkyl-phosphorus-containing flame retardants induced mitochondrial impairment and cell death in Chinese hamster ovary (CHO-k1) cells

    International Nuclear Information System (INIS)

    Huang, Chao; Li, Na; Yuan, Shengwu; Ji, Xiaoya; Ma, Mei; Rao, Kaifeng; Wang, Zijian

    2017-01-01

    Phosphorus-containing flame retardants (PFRs) are increasingly in demand worldwide as replacements for brominated flame retardants (BFRs), but insufficient available toxicological information on PFRs makes assessing their health risks challenging. Mitochondria are important targets of various environmental pollutants, and mitochondrial dysfunction may lead to many common diseases. In the present study, mitochondria impairment-related endpoints were measured by a high content screening (HCS) assay for 11 selected non-halogen PFRs in Chinese hamster ovary (CHO-k1) cells. A cluster analysis was used to categorize these PFRs into three groups according to their structural characteristics and results from the HCS assay. Two groups, containing long-chain alkyl-PFRs and all aryl-PFRs, were found to cause mitochondrial impairment but showed different mechanisms of toxicity. Due to the high correlation between cell death and mitochondrial impairment, two PFRs with different structures, trihexyl phosphate (THP) and cresyl diphenyl phosphate (CDP), were selected and compared with chlorpyrifos (CPF) to elucidate their mechanism of inducing cell death. THP (an alkyl-PFR) was found to utilize a similar pathway as CPF to induce apoptosis. However, cell death induced by CDP (an aryl-PFR) was different from classical necrosis based on experiments to discriminate among the different modes of cell death. These results confirm that mitochondria might be important targets for some PFRs and that differently structured PFRs could function via distinct mechanisms of toxicity. - Highlights: • Mitochondrial impairment induced by PFRs was observed in CHO-k1 cells. • THP (an alkyl-PFR) induced a caspase-mediated apoptosis in CHO-k1 cells. • The cell death induced by CDP (an aryl-PFR) was not traditional apoptosis or necrosis.

  11. Subwoofer and nanotube butterfly acoustic flame extinction

    NARCIS (Netherlands)

    Aliev, Ali E.; Mayo, Nathanael K.; Baughman, Ray H.; Mills, Brent T.; Habtour, Ed

    2017-01-01

    Nonchemical flame control using acoustic waves from a subwoofer and a lightweight carbon nanotube thermoacoustic projector was demonstrated. The intent was to manipulate flame intensity, direction and propagation. The mechanisms of flame suppression using low frequency acoustic waves were discussed.

  12. Emission flame spectrophotometry of chromium, cobalt, nickel trace amounts

    International Nuclear Information System (INIS)

    Prudnikov, Y.D.; Shapkina, Y.S.

    1976-01-01

    Chromium, cobalt, and nickel were determined in a flame spectrophotometer with a dual diffraction monochromator, DFS-12, in a high-temperature nitrogen-acetylene flame. The effect of ionization and the elements in the oxidizing flame was small. The lower limit of detection for the three elements is 1x10 -2 to 1 x10 -3 μg/ml, and the high selectivity of the analysis permits determining down to 10 -4 % Cr and Ni and to 10 -3 % Co. These elements may be determined in rocks and minerals from solutions prepared for analysis for alkali and alkali-earth elements. The possibilities of emission flame spectrophotometry are as great as those of atomic-absorption analysis, and it may be used for determining Cr, Co, and Ni in rocks and minerals, especially pure substances, metals, and other materials

  13. The geochemistry of stable chlorine and bromine isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Eggenkamp, Hans [Onderzock and Beleving, Bussum (Netherlands)

    2014-11-01

    First book solely dedicated to the geochemistry of chlorine and bromine isotopes. Detailed description of analytical techniques, including their advantages and disadvantages. Indication of research fields where measurement of these isotopes is especially useful. This book provides detailed information on the history, analysis and applications of chlorine and bromine isotope geochemistry. Chlorine and bromine are geochemically unique as they prefer to exist as single charged negative ions. For this reason isotope fractionation reflects mostly processes that are not related to changes in the redox state and this fractionation is generally modest. The book will describe the processes that are most easily detected using these isotopes. Also isotope variations, and processes that cause them, measured in oxidised species such as perchlorates and in organic molecules will be described in this book.

  14. Sodium, Iodine and Bromine in Polar Ice Cores

    DEFF Research Database (Denmark)

    Maffezzoli, Niccolo

    Abstract: This research focuses on sodium, bromine and iodine in polar ice cores, with the aim of reviewing and advancing their current understanding with additional measurements and records, and investigating the connections of these tracers with sea ice and their feasibility as sea ice indicators...... with a description of the main analytic al techniques used to measure ionic and elemental species in ice cores. Chapter 4 introduces sodium, bromine and iodine with a theoretical perspective and a particular focus on their connections with sea ice. Some of the physical and chemical properties that are believed...... back trajectory analyses of the past 17 years. The results identify the aerosol source area influencing the Renland ice cap, a result necessary for the interpretation of impurity records obtained from the ice core. Chapter 6 reviews the published ice/snow measurements of bromine and iodine at polar...

  15. On the theory of turbulent flame velocity

    OpenAIRE

    Bychkov, Vitaly; Akkerman, Vyacheslav; Petchenko, Arkady

    2012-01-01

    The renormalization ideas of self-similar dynamics of a strongly turbulent flame front are applied to the case of a flame with realistically large thermal expansion of the burning matter. In that case a flame front is corrugated both by external turbulence and the intrinsic flame instability. The analytical formulas for the velocity of flame propagation are obtained. It is demonstrated that the flame instability is of principal importance when the integral turbulent length scale is much large...

  16. Investigation of a flame holder geometry effect on flame structure in non-premixed combustion

    International Nuclear Information System (INIS)

    Hashemi, S. A.; Hajialigol, N.; Fattahi, A.; Heydari, R.; Mazaheri, K.

    2013-01-01

    In this paper the effect of flame holder geometry on flame structure is studied. The obtained numerical results using realizable k-ε and β-PDF models show a good agreement with experimental data. The results show that increasing in flame holder length decreases flame length and increases flame temperature. Additionally, it is observed that flame lengths decrease by increasing in flame holder radius and increase for larger radii. Furthermore in various radii, the flame temperature is higher for smaller flame lengths. It was found that behavior of flame structure is mainly affected by the mass flow rate of hot gases that come near the reactant by the recirculation zone.

  17. Investigation of a flame holder geometry effect on flame structure in non-premixed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Hashemi, S. A.; Hajialigol, N.; Fattahi, A.; Heydari, R. [University of Kashan, Kashan (Iran, Islamic Republic of); Mazaheri, K. [University of Tarbiat Moddares, Tehran (Iran, Islamic Republic of)

    2013-11-15

    In this paper the effect of flame holder geometry on flame structure is studied. The obtained numerical results using realizable k-ε and β-PDF models show a good agreement with experimental data. The results show that increasing in flame holder length decreases flame length and increases flame temperature. Additionally, it is observed that flame lengths decrease by increasing in flame holder radius and increase for larger radii. Furthermore in various radii, the flame temperature is higher for smaller flame lengths. It was found that behavior of flame structure is mainly affected by the mass flow rate of hot gases that come near the reactant by the recirculation zone.

  18. An Efficient and Facile Methodology for Bromination of Pyrimidine and Purine Nucleosides with Sodium Monobromoisocyanurate (SMBI

    Directory of Open Access Journals (Sweden)

    Roger Stromberg

    2013-10-01

    Full Text Available An efficient and facile strategy has been developed for bromination of nucleosides using sodium monobromoisocyanurate (SMBI. Our methodology demonstrates bromination at the C-5 position of pyrimidine nucleosides and the C-8 position of purine nucleosides. Unprotected and also several protected nucleosides were brominated in moderate to high yields following this procedure.

  19. Polydisperse effects in jet spray flames

    Science.gov (United States)

    Weinberg, Noam; Greenberg, J. Barry

    2018-01-01

    A laminar jet polydisperse spray diffusion flame is analysed mathematically for the first time using an extension of classical similarity solutions for gaseous jet flames. The analysis enables a comparison to be drawn between conditions for flame stability or flame blow-out for purely gaseous flames and for spray flames. It is found that, in contrast to the Schmidt number criteria relevant to gas flames, droplet size and initial spray polydispersity play a critical role in determining potential flame scenarios. Some qualitative agreement for lift-off height is found when comparing predictions of the theory and sparse independent experimental evidence from the literature.

  20. Chlorinated, brominated and fluorinated organic pollutants in African Penguin eggs: 30 years since the previous assessment.

    Science.gov (United States)

    Bouwman, Hindrik; Govender, Danny; Underhill, Les; Polder, Anuschka

    2015-05-01

    The African Penguin population has drastically declined over the last 100 years. Changes in food availability due to over-fishing and other oceanographic changes seem to be major causes. However, it has also been 30 years since organic pollutants as a potential factor have been assessed. We analysed penguin eggs collected in 2011 and 2012 from two breeding colonies 640 km apart: Robben Island near Cape Town on the Atlantic Ocean coast, and Bird Island near Port Elizabeth on the Indian Ocean coast of South Africa. We quantified organochlorine pesticides, brominated flame retardants, and perfluorinated compounds (PFCs). Compared to 30 years ago, concentrations of ΣDDT have remained about the same or slightly lower, while ΣPCBs declined almost four-fold. The use of DDT in malaria control is unlikely to have contributed. PFCs were detected in all eggs. Indications (non-significant) of eggshell thinning associated with ΣDDT and ΣPCB was found. It seems therefore that the concentrations of measured organic pollutants the African Penguin eggs are not contributing directly to its current demise, but concerns remain about thinner shells and desiccation. Effects of combinations of compounds and newer compounds cannot be excluded, as well as more subtle effects on reproduction, development, and behaviour. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Dynamics and structure of stretched flames

    Energy Technology Data Exchange (ETDEWEB)

    Law, C.K. [Princeton Univ., NJ (United States)

    1993-12-01

    This program aims to gain fundamental understanding on the structure, geometry, and dynamics of laminar premixed flames, and relate these understanding to the practical issues of flame extinction and stabilization. The underlying fundamental interest here is the recent recognition that the response of premixed flames can be profoundly affected by flame stretch, as manifested by flow nonuniformity, flame curvature, and flame/flow unsteadiness. As such, many of the existing understanding on the behavior of premixed flames need to be qualitatively revised. The research program consists of three major thrusts: (1) detailed experimental and computational mapping of the structure of aerodynamically-strained planar flames, with emphasis on the effects of heat loss, nonequidiffusion, and finite residence time on the flame thickness, extent of incomplete reaction, and the state of extinction. (2) Analytical study of the geometry and dynamics of stretch-affected wrinkled flame sheets in simple configurations, as exemplified by the Bunsen flame and the spatially-periodic flame, with emphasis on the effects of nonlinear stretch, the phenomena of flame cusping, smoothing, and tip opening, and their implications on the structure and burning rate of turbulent flames. (3) Stabilization and blowoff of two-dimensional inverted premixed and stabilization and determining the criteria governing flame blowoff. The research is synergistically conducted through the use of laser-based diagnostics, computational simulation of the flame structure with detailed chemistry and transport, and mathematical analysis of the flame dynamics.

  2. Electrospun Nafion®/Polyphenylsulfone Composite Membranes for Regenerative Hydrogen Bromine Fuel Cells

    Science.gov (United States)

    Park, Jun Woo; Wycisk, Ryszard; Pintauro, Peter N.; Yarlagadda, Venkata; Van Nguyen, Trung

    2016-01-01

    The regenerative H2/Br2-HBr fuel cell, utilizing an oxidant solution of Br2 in aqueous HBr, shows a number of benefits for grid-scale electricity storage. The membrane-electrode assembly, a key component of a fuel cell, contains a proton-conducting membrane, typically based on the perfluorosulfonic acid (PFSA) ionomer. Unfortunately, the high cost of PFSA membranes and their relatively high bromine crossover are serious drawbacks. Nanofiber composite membranes can overcome these limitations. In this work, composite membranes were prepared from electrospun dual-fiber mats containing Nafion® PFSA ionomer for facile proton transport and an uncharged polymer, polyphenylsulfone (PPSU), for mechanical reinforcement, and swelling control. After electrospinning, Nafion/PPSU mats were converted into composite membranes by softening the PPSU fibers, through exposure to chloroform vapor, thus filling the voids between ionomer nanofibers. It was demonstrated that the relative membrane selectivity, referenced to Nafion® 115, increased with increasing PPSU content, e.g., a selectivity of 11 at 25 vol% of Nafion fibers. H2-Br2 fuel cell power output with a 65 μm thick membrane containing 55 vol% Nafion fibers was somewhat better than that of a 150 μm Nafion® 115 reference, but its cost advantage due to a four-fold decrease in PFSA content and a lower bromine species crossover make it an attractive candidate for use in H2/Br2-HBr systems. PMID:28773268

  3. Electrospun Nafion®/Polyphenylsulfone Composite Membranes for Regenerative Hydrogen Bromine Fuel Cells.

    Science.gov (United States)

    Park, Jun Woo; Wycisk, Ryszard; Pintauro, Peter N; Yarlagadda, Venkata; Van Nguyen, Trung

    2016-02-29

    The regenerative H₂/Br₂-HBr fuel cell, utilizing an oxidant solution of Br₂ in aqueous HBr, shows a number of benefits for grid-scale electricity storage. The membrane-electrode assembly, a key component of a fuel cell, contains a proton-conducting membrane, typically based on the perfluorosulfonic acid (PFSA) ionomer. Unfortunately, the high cost of PFSA membranes and their relatively high bromine crossover are serious drawbacks. Nanofiber composite membranes can overcome these limitations. In this work, composite membranes were prepared from electrospun dual-fiber mats containing Nafion ® PFSA ionomer for facile proton transport and an uncharged polymer, polyphenylsulfone (PPSU), for mechanical reinforcement, and swelling control. After electrospinning, Nafion/PPSU mats were converted into composite membranes by softening the PPSU fibers, through exposure to chloroform vapor, thus filling the voids between ionomer nanofibers. It was demonstrated that the relative membrane selectivity, referenced to Nafion ® 115, increased with increasing PPSU content, e.g., a selectivity of 11 at 25 vol% of Nafion fibers. H₂-Br₂ fuel cell power output with a 65 μm thick membrane containing 55 vol% Nafion fibers was somewhat better than that of a 150 μm Nafion ® 115 reference, but its cost advantage due to a four-fold decrease in PFSA content and a lower bromine species crossover make it an attractive candidate for use in H₂/Br₂-HBr systems.

  4. Electrospun Nafion®/Polyphenylsulfone Composite Membranes for Regenerative Hydrogen Bromine Fuel Cells

    Directory of Open Access Journals (Sweden)

    Jun Woo Park

    2016-02-01

    Full Text Available The regenerative H2/Br2-HBr fuel cell, utilizing an oxidant solution of Br2 in aqueous HBr, shows a number of benefits for grid-scale electricity storage. The membrane-electrode assembly, a key component of a fuel cell, contains a proton-conducting membrane, typically based on the perfluorosulfonic acid (PFSA ionomer. Unfortunately, the high cost of PFSA membranes and their relatively high bromine crossover are serious drawbacks. Nanofiber composite membranes can overcome these limitations. In this work, composite membranes were prepared from electrospun dual-fiber mats containing Nafion® PFSA ionomer for facile proton transport and an uncharged polymer, polyphenylsulfone (PPSU, for mechanical reinforcement, and swelling control. After electrospinning, Nafion/PPSU mats were converted into composite membranes by softening the PPSU fibers, through exposure to chloroform vapor, thus filling the voids between ionomer nanofibers. It was demonstrated that the relative membrane selectivity, referenced to Nafion® 115, increased with increasing PPSU content, e.g., a selectivity of 11 at 25 vol% of Nafion fibers. H2-Br2 fuel cell power output with a 65 μm thick membrane containing 55 vol% Nafion fibers was somewhat better than that of a 150 μm Nafion® 115 reference, but its cost advantage due to a four-fold decrease in PFSA content and a lower bromine species crossover make it an attractive candidate for use in H2/Br2-HBr systems.

  5. Highly stabilized partially premixed flames of propane in a concentric flow conical nozzle burner with coflow

    KAUST Repository

    Elbaz, Ayman M.

    2018-01-11

    Partially premixed turbulent flames with non-homogeneous jet of propane were generated in a concentric flow conical nozzle burner in order to investigate the effect of the coflow on the stability and flame structure. The flame stability is first mapped and then high-speed stereoscopic particle image velocimetry, SPIV, plus OH planar laser-induced fluorescence, OH-PLIF, measurements were conducted on a subset of four flames. The jet equivalence ratio Φ = 2, Jet exit Reynolds number Re = 10,000, and degree of premixing are kept constant for the selected flames, while the coflow velocity, Uc, is progressively changed from 0 to 15 m/s. The results showed that the flame is stable between two extinction limits of mixture inhomogeneity, and the optimum stability is obtained at certain degree of mixture inhomogeneity. Increasing Φ, increases the span between these two extinction limits, while these limits converge to a single point (corresponding to optimum mixture inhomogeneity) with increasing Re. Regardless the value of Φ, increasing the coflow velocity improves the flame stability. The correlation between recessed distance of the burner tubes and the fluctuation of the mixture fraction, Δξ, shows that at Δξ around 40% of the flammability limits leads to optimum flame stability. The time averaged SPIV results show that the coflow induces a big annular recirculation zone surrounds the jet flames. The size and the location of this zone is seen to be sensitive to Uc. However, the instantaneous images show the existence of a small vortical structure close to the shear layer, where the flame resides there in the case of no-coflow. These small vertical structures are seen playing a vital role in the flame structure, and increasing the flame corrugation close to the nozzle exit. Increasing the coflow velocity expands the central jet at the expense of the jet velocity, and drags the flame in the early flame regions towards the recirculation zone, where the flame tracks

  6. Ion imprinted activated carbon solid-phase extraction coupled to flame atomic absorption spectrometry for selective determination of lead ions in environmental samples

    International Nuclear Information System (INIS)

    Naraghi, Kiyana; Panahi, Homayon Ahmad; Hassani, Amir Hesam; Moniri, Elham

    2014-01-01

    A simple lead ion imprinted sorbent was synthesized by coupling activated carbon with a known metal chelating compound, iminodiacetic acid. The ion imprinted sorbent has been characterized using Fourier transform infrared spectroscopy, elemental analysis and thermogravimetric analysis and subjected for the extraction and determination of trace Pb(II) in environmental water samples. The optimum pH value for sorption of the lead ion was 6.5. The sorption capacity of lead imprinted sorbent was 42.2 mg g"−"1. The chelating imprinted sorbent can be reused for five cycles of sorption-desorption without any significant change in sorption capacity. Compared with non-imprinted polymer particles, the lead ion imprinted sorbent showed high adsorption capacity, significant selectivity, good site accessibility for Pb(II). The equilibrium adsorption data of Pb(II) by modified resin were analyzed by Langmuir, Freundlich, Temkin and Redlich-Peterson models

  7. Ion imprinted activated carbon solid-phase extraction coupled to flame atomic absorption spectrometry for selective determination of lead ions in environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Naraghi, Kiyana; Panahi, Homayon Ahmad; Hassani, Amir Hesam [Islamic Azad University, Tehran (Korea, Republic of); Moniri, Elham [Islamic Azad University, Varamin (Iran, Islamic Republic of)

    2014-10-15

    A simple lead ion imprinted sorbent was synthesized by coupling activated carbon with a known metal chelating compound, iminodiacetic acid. The ion imprinted sorbent has been characterized using Fourier transform infrared spectroscopy, elemental analysis and thermogravimetric analysis and subjected for the extraction and determination of trace Pb(II) in environmental water samples. The optimum pH value for sorption of the lead ion was 6.5. The sorption capacity of lead imprinted sorbent was 42.2 mg g{sup −1}. The chelating imprinted sorbent can be reused for five cycles of sorption-desorption without any significant change in sorption capacity. Compared with non-imprinted polymer particles, the lead ion imprinted sorbent showed high adsorption capacity, significant selectivity, good site accessibility for Pb(II). The equilibrium adsorption data of Pb(II) by modified resin were analyzed by Langmuir, Freundlich, Temkin and Redlich-Peterson models.

  8. Novel and simple synthesis of brominated 1,10-phenanthrolines

    Czech Academy of Sciences Publication Activity Database

    Výprachtický, Drahomír; Kaňková, Dana; Pokorná, Veronika; Kmínek, Ivan; Dzhabarov, Vagif; Cimrová, Věra

    2014-01-01

    Roč. 67, č. 6 (2014), s. 915-921 ISSN 0004-9425 R&D Projects: GA ČR GAP106/12/0827; GA ČR(CZ) GA13-26542S Institutional support: RVO:61389013 Keywords : 1,10-phenanthroline * electrophilic aromatic substitution * bromination Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.558, year: 2014

  9. Self-assembled growth of nanostructural Ge islands on bromine ...

    Indian Academy of Sciences (India)

    bromine-passivated Si(111) surfaces at room temperature. AMAL K DAS1 ... Both the islands and the layer are nanocrystalline. This appears ..... coworkers estimated an activation energy of 0.59 ±0.1 eV for Ge diffusion on Si(100) and 0.45 eV ...

  10. Estimation of the residual bromine concentration after disinfection of cooling water by statistical evaluation.

    Science.gov (United States)

    Megalopoulos, Fivos A; Ochsenkuehn-Petropoulou, Maria T

    2015-01-01

    A statistical model based on multiple linear regression is developed, to estimate the bromine residual that can be expected after the bromination of cooling water. Make-up water sampled from a power plant in the Greek territory was used for the creation of the various cooling water matrices under investigation. The amount of bromine fed to the circuit, as well as other important operational parameters such as concentration at the cooling tower, temperature, organic load and contact time are taken as the independent variables. It is found that the highest contribution to the model's predictive ability comes from cooling water's organic load concentration, followed by the amount of bromine fed to the circuit, the water's mean temperature, the duration of the bromination period and finally its conductivity. Comparison of the model results with the experimental data confirms its ability to predict residual bromine given specific bromination conditions.

  11. Mechanistic aspects of ionic reactions in flames

    DEFF Research Database (Denmark)

    Egsgaard, H.; Carlsen, L.

    1993-01-01

    Some fundamentals of the ion chemistry of flames are summarized. Mechanistic aspects of ionic reactions in flames have been studied using a VG PlasmaQuad, the ICP-system being substituted by a simple quartz burner. Simple hydrocarbon flames as well as sulfur-containing flames have been investigated...

  12. Bromine measurements in ozone depleted air over the Arctic Ocean

    Directory of Open Access Journals (Sweden)

    J. A. Neuman

    2010-07-01

    Full Text Available In situ measurements of ozone, photochemically active bromine compounds, and other trace gases over the Arctic Ocean in April 2008 are used to examine the chemistry and geographical extent of ozone depletion in the arctic marine boundary layer (MBL. Data were obtained from the NOAA WP-3D aircraft during the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC study and the NASA DC-8 aircraft during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS study. Fast (1 s and sensitive (detection limits at the low pptv level measurements of BrCl and BrO were obtained from three different chemical ionization mass spectrometer (CIMS instruments, and soluble bromide was measured with a mist chamber. The CIMS instruments also detected Br2. Subsequent laboratory studies showed that HOBr rapidly converts to Br2 on the Teflon instrument inlets. This detected Br2 is identified as active bromine and represents a lower limit of the sum HOBr + Br2. The measured active bromine is shown to likely be HOBr during daytime flights in the arctic. In the MBL over the Arctic Ocean, soluble bromide and active bromine were consistently elevated and ozone was depleted. Ozone depletion and active bromine enhancement were confined to the MBL that was capped by a temperature inversion at 200–500 m altitude. In ozone-depleted air, BrO rarely exceeded 10 pptv and was always substantially lower than soluble bromide that was as high as 40 pptv. BrCl was rarely enhanced above the 2 pptv detection limit, either in the MBL, over Alaska, or in the arctic free troposphere.

  13. A novel task specific magnetic polymeric ionic liquid for selective preconcentration of potassium in oil samples using centrifuge-less dispersive liquid-liquid microextraction technique and its determination by flame atomic emission spectroscopy.

    Science.gov (United States)

    Beiraghi, Asadollah; Shokri, Masood

    2018-02-01

    In the present study a new centrifuge-less dispersive liquid-liquid microextraction technique based on application of a new task specific magnetic polymeric ionic liquid (TSMPIL) as a chelating and extraction solvent for selective preconcentration of trace amounts of potassium from oil samples is developed, for the first time. After extraction, the fine droplets of TSMPIL were transferred into an eppendorf tube and diluted to 500µL using distilled water. Then, the enriched analyte was determined by flame atomic emission spectroscopy (FAES). Several important factors affecting both the complexation and extraction efficiency including extraction time, rate of vortex agitator, amount of carbonyl iron powder, pH of sample solution, volume of ionic liquid as well as effects of interfering species were investigated and optimized. Under the optimal conditions, the limits of detection (LOD) and quantification (LOQ) were 0.5 and 1.6µgL -1 respectively with the preconcentration factor of 128. The precision (RSD %) for seven replicate determinations at 10µgL -1 of potassium was better than 3.9%. The relative recoveries for the spiked samples were in the acceptable range of 95-104%. The results demonstrated that no remarkable interferences are created by other various ions in the determination of potassium, so that the tolerance limits (W Ion /W K ) of major cations and anions were in the range of 2500-10,000. The purposed method was successfully applied for the analysis of potassium in some oil samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Environmental concentration and atmospheric deposition of halogenated flame retardants in soil from Nepal: Source apportionment and soil-air partitioning.

    Science.gov (United States)

    Yadav, Ishwar Chandra; Devi, Ningombam Linthoingambi; Li, Jun; Zhang, Gan

    2018-02-01

    While various investigations have been driven on polybrominated diphenyl ethers (PBDEs) and other flame retardants (FRs) in different framework around the world, information about contamination and fate of PBDEs and other FRs in developing countries especially in the Indian subcontinent is uncommon. Nepal being located in the Indian subcontinent, very little is known about contamination level of semi-volatile organic pollutants discharged into the environment. This motivated us to investigate the environmental fate of halogenated flame retardant (HFRs) in Nepalese condition. In this study, we investigated the concentration, fate, and sources of 9 PBDEs, 2 dechlorane plus isomers (DPs), and 6 novel brominated flame retardants (NBFRs). Moreover, air-soil exchange and soil-air partitioning were also evaluated to characterize the pattern of air-soil exchange and environmental fate. In general, the concentrations of NBFRs in soil were more prevalent than PBDEs and DPs, and accounted 95% of ∑HFRs. By and large, the concentrations of NBFRs and DPs were measured high in Kathmandu, while PBDEs level exceeded in Pokhara. Principal component analysis (PCA) study suggested contributions from commercial penta-, octa-, and deca-BDEs products and de-bromination of highly brominated PBDEs as the significant source of PBDEs. Likewise, low f anti ratio suggested DPs in soil might have originated from long-range atmospheric transport from remote areas, while high levels of decabromodiphenyl ethane (DBDPE) in soil were linked with the use of wide varieties of consumer products. The estimated fugacity fraction (ff) for individual HFR was quite lower (soil is overwhelming. Soil-air partitioning study revealed neither octanol-air partition coefficient (K OA ) nor black carbon partition coefficient (K BC-A ) is an appropriate surrogate for soil organic matter (SOM), subsequently, absorption by SOM has no or little role in the partitioning of HFRs. Copyright © 2017 Elsevier Ltd. All

  15. Role of the outer-edge flame on flame extinction in nitrogen-diluted non-premixed counterflow flames with finite burner diameters

    KAUST Repository

    Chung, Yong Ho; Park, Daegeun; Park, Jeong; Kwon, Oh Boong; Yun, Jin Han; Keel, Sang In

    2013-01-01

    This study of nitrogen-diluted non-premixed counterflow flames with finite burner diameters investigates the important role of the outer-edge flame on flame extinction through experimental and numerical analyses. It explores flame stability diagrams

  16. Flame spraying of polymers

    International Nuclear Information System (INIS)

    Varacalle, D.J. Jr.; Zeek, D.P.; Couch, K.W.; Benson, D.M.; Kirk, S.M.

    1997-01-01

    Statistical design-of-experiment studies of the thermal spraying of polymer powders are presented. Studies of the subsonic combustion (i.e., Flame) process were conducted in order to determine the quality and economics of polyester and urethane coatings. Thermally sprayed polymer coatings are of interest to several industries for anticorrosion applications, including the chemical, automotive, and aircraft industries. In this study, the coating design has been optimized for a site-specific application using Taguchi-type fractional-factorial experiments. Optimized coating designs are presented for the two powder systems. A substantial range of thermal processing conditions and their effect on the resultant polymer coatings is presented. The coatings were characterized by optical metallography, hardness testing, tensile testing, and compositional analysis. Characterization of the coatings yielded the thickness, bond strength, Knoop microhardness, roughness, deposition efficiency, and porosity. Confirmation testing was accomplished to verify the coating designs

  17. Physical and Chemical Processes in Turbulent Flames

    Science.gov (United States)

    2015-06-23

    equiangular sectors, defined as the ratio of the actual flame length to the length of a circular-arc of radius equal to the average flame radius. Assuming... flame length ratio obtained directly from the experiments, without any assumption. As explained earlier (Eq. 2.8) the length ratio, (LR=dl(G0)/dl0) is...spherically expanding flames, with the length ratio on the measurement plane, at predefined equiangular sectors, defined as the ratio of the actual flame length to

  18. Brominated and fluorinated organic pollutants in the breast milk of first-time Irish mothers: is there a relationship to levels in food?

    LENUS (Irish Health Repository)

    Pratt, Iona

    2013-01-01

    Brominated flame retardants - polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), hexabromocyclododecane (HBCD) and others - have been measured in 11 pooled breast milk samples from 109 first-time mothers in Ireland. Additionally, the study has measured levels of polybrominated dibenzo-p-dioxins and furans (PBDD\\/Fs), mixed halogenated dioxins (PXCC\\/Fs) and biphenyls (PXBs), polychlorinated naphthalenes (PCNs) and perfluoroalkylated substances (PFAS) in these samples. The mean sum of 19 PBDEs including BDE-209 was 4.85 ng g(-1) fat, which is comparable with that found in other European countries. BDE-47, BDE-153, BDE-209, BDE-99 and BDE-100 were found at the highest concentrations. The only PBBs detected consistently were BB-77, BB-126 and BB-153, with highest concentrations being found for BB-153 (mean = 0.13 ng g(-1) fat). The mean sum of HBCD enantiomers was 3.52 ng g(-1) fat, with α-HBCD representing over 70% of the total. Of the other brominated flame retardants - tetrabromobisphenol-A (TBBP-A), hexabromobenzene (HBB), decabromodiphenylethane (DBDPE) and bis(2,4,6-tribromophenoxyethane) (BTBPE) - examined, only TBBP-A was detected above the limit of detection (LOD), in two of the 11 pools analysed. All measured PBDF congeners were observed (at 0.02-0.91 pg g(-1) fat), but 2,3,7,8-tetrabromo-dibenzodioxin (TeBDD) was the only PBDD detected, with a mean concentration of 0.09 pg g(-1) fat. The occurrence of the mixed chlorinated\\/brominated dibenzodioxins, dibenzofurans and biphenyls, 2-B-3,7,8-CDD, 2,3-B-7,8-CDF, 4-B-2,3,7,8-CDF, PXB 105, PXB 118, PXB 126 and PCB 156 in breast milk in the current study may indicate that levels of these contaminants are increasing in the environment. Polychlorinated naphthalenes were detected in all samples, but not perfluorooctane sulfonate (PFOS) and other PFAS. The pattern of occurrence of these brominated and fluorinated persistent organic pollutants (POPs) in Irish breast milk shows a general

  19. Supplementary Material for: Measurements of Positively Charged Ions in Premixed Methane-Oxygen Atmospheric Flames

    KAUST Repository

    Alquaity, Awad B. S.

    2017-01-01

    Cations and anions are formed as a result of chemi-ionization processes in combustion systems. Electric fields can be applied to reduce emissions and improve combustion efficiency by active control of the combustion process. Detailed flame ion chemistry models are needed to understand and predict the effect of external electric fields on combustion plasmas. In this work, a molecular beam mass spectrometer (MBMS) is utilized to measure ion concentration profiles in premixed methane–oxygen argon burner-stabilized atmospheric flames. Lean and stoichiometric flames are considered to assess the dependence of ion chemistry on flame stoichiometry. Relative ion concentration profiles are compared with numerical simulations using various temperature profiles, and good qualitative agreement was observed for the stoichiometric flame. However, for the lean flame, numerical simulations misrepresent the spatial distribution of selected ions greatly. Three modifications are suggested to enhance the ion mechanism and improve the agreement between experiments and simulations. The first two modifications comprise the addition of anion detachment reactions to increase anion recombination at low temperatures. The third modification involves restoring a detachment reaction to its original irreversible form. To our knowledge, this work presents the first detailed measurements of cations and flame temperature in canonical methane–oxygen-argon atmospheric flat flames. The positive ion profiles reported here may be useful to validate and improve ion chemistry models for methane-oxygen flames.

  20. Measurements of Positively Charged Ions in Premixed Methane-Oxygen Atmospheric Flames

    KAUST Repository

    Alquaity, Awad

    2016-08-22

    Cations and anions are formed as a result of chemi-ionization processes in combustion systems. Electric fields can be applied to reduce emissions and improve combustion efficiency by active control of the combustion process. Detailed flame ion chemistry models are needed to understand and predict the effect of external electric fields on combustion plasmas. In this work, a molecular beam mass spectrometer (MBMS) is utilized to measure ion concentration profiles in premixed methane–oxygen argon burner-stabilized atmospheric flames. Lean and stoichiometric flames are considered to assess the dependence of ion chemistry on flame stoichiometry. Relative ion concentration profiles are compared with numerical simulations using various temperature profiles, and good qualitative agreement was observed for the stoichiometric flame. However, for the lean flame, numerical simulations misrepresent the spatial distribution of selected ions greatly. Three modifications are suggested to enhance the ion mechanism and improve the agreement between experiments and simulations. The first two modifications comprise the addition of anion detachment reactions to increase anion recombination at low temperatures. The third modification involves restoring a detachment reaction to its original irreversible form. To our knowledge, this work presents the first detailed measurements of cations and flame temperature in canonical methane–oxygen-argon atmospheric flat flames. The positive ion profiles reported here may be useful to validate and improve ion chemistry models for methane-oxygen flames.

  1. Extinction of laminar partially premixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, Suresh K. [Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, 842 W. Taylor Street, Room 2039, MC-251, Chicago, IL 60607-7022 (United States)

    2009-12-15

    Flame extinction represents one of the classical phenomena in combustion science. It is important to a variety of combustion systems in transportation and power generation applications. Flame extinguishment studies are also motivated from the consideration of fire safety and suppression. Such studies have generally considered non-premixed and premixed flames, although fires can often originate in a partially premixed mode, i.e., fuel and oxidizer are partially premixed as they are transported to the reaction zone. Several recent investigations have considered this scenario and focused on the extinction of partially premixed flames (PPFs). Such flames have been described as hybrid flames possessing characteristics of both premixed and non-premixed flames. This paper provides a review of studies dealing with the extinction of PPFs, which represent a broad family of flames, including double, triple (tribrachial), and edge flames. Theoretical, numerical and experimental studies dealing with the extinction of such flames in coflow and counterflow configurations are discussed. Since these flames contain both premixed and non-premixed burning zones, a brief review of the dilution-induced extinction of premixed and non-premixed flames is also provided. For the coflow configuration, processes associated with flame liftoff and blowout are described. Since lifted non-premixed jet flames often contain a partially premixed or an edge-flame structure prior to blowout, the review also considers such flames. While the perspective of this review is broad focusing on the fundamental aspects of flame extinction and blowout, results mostly consider flame extinction caused by the addition of a flame suppressant, with relevance to fire suppression on earth and in space environment. With respect to the latter, the effect of gravity on the extinction of PPFs is discussed. Future research needs are identified. (author)

  2. Edge flame instability in low-strain-rate counterflow diffusion flames

    Energy Technology Data Exchange (ETDEWEB)

    Park, June Sung; Hwang, Dong Jin; Park, Jeong; Kim, Jeong Soo; Kim, Sungcho [School of Mechanical and Aerospace Engineering, Sunchon National University, 315 Maegok-dong, Suncheon, Jeonnam 540-742 (Korea, Republic of); Keel, Sang In [Environment & amp; Energy Research Division, Korea Institute of Machinery and Materials, P.O. Box 101, Yusung-gu, Taejon 305-343 (Korea, Republic of); Kim, Tae Kwon [School of Mechanical & amp; Automotive Engineering, Keimyung University, 1000 Sindang-dong, Dalseo-gu, Daegu 704-701 (Korea, Republic of); Noh, Dong Soon [Energy System Research Department, Korea Institute of Energy Research, 71-2 Jang-dong, Yusung-gu, Taejon 305-343 (Korea, Republic of)

    2006-09-15

    Experiments in low-strain-rate methane-air counterflow diffusion flames diluted with nitrogen have been conducted to study flame extinction behavior and edge flame oscillation in which flame length is less than the burner diameter and thus lateral conductive heat loss, in addition to radiative loss, could be high at low global strain rates. The critical mole fraction at flame extinction is examined in terms of velocity ratio and global strain rate. Onset conditions of the edge flame oscillation and the relevant modes are also provided with global strain rate and nitrogen mole fraction in the fuel stream or in terms of fuel Lewis number. It is observed that flame length is intimately relevant to lateral heat loss, and this affects flame extinction and edge flame oscillation considerably. Lateral heat loss causes flame oscillation even at fuel Lewis number less than unity. Edge flame oscillations, which result from the advancing and retreating edge flame motion of the outer flame edge of low-strain-rate flames, are categorized into three modes: a growing, a decaying, and a harmonic-oscillation mode. A flame stability map based on the flame oscillation modes is also provided for low-strain-rate flames. The important contribution of lateral heat loss even to edge flame oscillation is clarified finally. (author)

  3. Occupational exposure to polybrominated diphenyl ethers (PBDEs) and other flame retardant foam additives at gymnastics studios: Before, during and after the replacement of pit foam with PBDE-free foams.

    Science.gov (United States)

    Ceballos, Diana M; Broadwater, Kendra; Page, Elena; Croteau, Gerry; La Guardia, Mark J

    2018-07-01

    Coaches spend long hours training gymnasts of all ages aided by polyurethane foam used in loose blocks, mats, and other padded equipment. Polyurethane foam can contain flame retardant additives such as polybrominated diphenyl ethers (PBDEs), to delay the spread of fires. However, flame retardants have been associated with endocrine disruption and carcinogenicity. The National Institute for Occupational Safety and Health (NIOSH) evaluated employee exposure to flame retardants in four gymnastics studios utilized by recreational and competitive gymnasts. We evaluated flame retardant exposure at the gymnastics studios before, during, and after the replacement of foam blocks used in safety pits with foam blocks certified not to contain several flame retardants, including PBDEs. We collected hand wipes on coaches to measure levels of flame retardants on skin before and after their work shift. We measured flame retardant levels in the dust on window glass in the gymnastics areas and office areas, and in the old and new foam blocks used throughout the gymnastics studios. We found statistically higher levels of 9 out of 13 flame retardants on employees' hands after work than before, and this difference was reduced after the foam replacement. Windows in the gymnastics areas had higher levels of 3 of the 13 flame retardants than windows outside the gymnastics areas, suggesting that dust and vapor containing flame retardants became airborne. Mats and other padded equipment contained levels of bromine consistent with the amount of brominated flame retardants in foam samples analyzed in the laboratory. New blocks did not contain PBDEs, but did contain the flame retardants 2-ethylhexyl 2,3,4,5-tetrabromobenzoate and 2-ethylhexyl 2,3,4,5-tetrabromophthalate. We conclude that replacing the pit foam blocks eliminated a source of PBDEs, but not 2-ethylhexyl 2,3,4,5-tetrabromobenzoate and 2-ethylhexyl 2,3,4,5-tetrabromophthalate. We recommend ways to further minimize employee exposure

  4. Stratified turbulent Bunsen flames: flame surface analysis and flame surface density modelling

    Science.gov (United States)

    Ramaekers, W. J. S.; van Oijen, J. A.; de Goey, L. P. H.

    2012-12-01

    In this paper it is investigated whether the Flame Surface Density (FSD) model, developed for turbulent premixed combustion, is also applicable to stratified flames. Direct Numerical Simulations (DNS) of turbulent stratified Bunsen flames have been carried out, using the Flamelet Generated Manifold (FGM) reduction method for reaction kinetics. Before examining the suitability of the FSD model, flame surfaces are characterized in terms of thickness, curvature and stratification. All flames are in the Thin Reaction Zones regime, and the maximum equivalence ratio range covers 0.1⩽φ⩽1.3. For all flames, local flame thicknesses correspond very well to those observed in stretchless, steady premixed flamelets. Extracted curvature radii and mixing length scales are significantly larger than the flame thickness, implying that the stratified flames all burn in a premixed mode. The remaining challenge is accounting for the large variation in (subfilter) mass burning rate. In this contribution, the FSD model is proven to be applicable for Large Eddy Simulations (LES) of stratified flames for the equivalence ratio range 0.1⩽φ⩽1.3. Subfilter mass burning rate variations are taken into account by a subfilter Probability Density Function (PDF) for the mixture fraction, on which the mass burning rate directly depends. A priori analysis point out that for small stratifications (0.4⩽φ⩽1.0), the replacement of the subfilter PDF (obtained from DNS data) by the corresponding Dirac function is appropriate. Integration of the Dirac function with the mass burning rate m=m(φ), can then adequately model the filtered mass burning rate obtained from filtered DNS data. For a larger stratification (0.1⩽φ⩽1.3), and filter widths up to ten flame thicknesses, a β-function for the subfilter PDF yields substantially better predictions than a Dirac function. Finally, inclusion of a simple algebraic model for the FSD resulted only in small additional deviations from DNS data

  5. Competition between Halogen, Hydrogen and Dihydrogen Bonding in Brominated Carboranes

    Czech Academy of Sciences Publication Activity Database

    Fanfrlík, Jindřich; Holub, Josef; Růžičková, Z.; Řezáč, Jan; Lane, P. D.; Wann, D. A.; Hnyk, Drahomír; Růžička, A.; Hobza, Pavel

    2016-01-01

    Roč. 17, č. 21 (2016), s. 3373-3376 ISSN 1439-4235 R&D Projects: GA ČR(CZ) GBP208/12/G016; GA ČR(CZ) GA15-05677S Institutional support: RVO:61388963 ; RVO:61388980 Keywords : bromine * carboranes * halogen bonds * sigma holes * X-ray crystal structure Subject RIV: CF - Physical ; Theoretical Chemistry; CA - Inorganic Chemistry (UACH-T) Impact factor: 3.075, year: 2016

  6. Overview of the Fire Lab at Missoula Experiments (FLAME)

    Science.gov (United States)

    S. M. Kreidenweis; J. L. Collett; H. Moosmuller; W. P. Arnott; WeiMin Hao; W. C. Malm

    2010-01-01

    The Fire Lab at Missoula Experiments (FLAME) used a series of open biomass burns, conducted in 2006 and 2007 at the Forest Service Fire Science Laboratory in Missoula, MT, to characterize the physical, chemical and optical properties of biomass combustion emissions. Fuels were selected primarily based on their projected importance for emissions from prescribed and wild...

  7. Gaseous diffusion flames: simple structures and their interaction

    Energy Technology Data Exchange (ETDEWEB)

    Cavaliere, A. [Universita degli Studi Federico II, Naples (Italy). Dip. di Ingegneria Chimica; Ragucci, R. [Istituto di Ricerche sulla Combustione C,N.R., Naples (Italy)

    2001-07-01

    This is a synoptic overview of a selection of works dealing with single diffusive structures, with their mutual interaction in simple flows and their statistical modeling in complex flows. The focus is on reacting conditions pertaining to gaseous diffusion flames, but isothermal structures are also described when they are of some conceptual interest. This paper considers only few representative works for each subject, which are functional in explaining the key characteristics of the diffusive structures. The extension, given to single subjects, is not weighed according to the number of related publications but on the relevance to the basic understanding of the general framework concerning diffusion flames. One-dimensional structures are first discussed. They are ordered according to the number of balance equation terms needed for their description. Two-dimensional (2D) structures are then introduced following an order based on their convolution level. Some pioneering work on three-dimensional structures is further quoted. The temporal evolution of simple structures in quiescent or simple flowing 2D systems is considered. The latter case is exploited to present classification of diffusion-controlled mixing regimes. Modeling characterization approach of turbulent diffusion flames is also described in order to yield a self-sufficient didactic presentation. The approach based on the flame surface density model is specifically discussed because of its potential use in the determination of qualitative and quantitative features of simple diffusion flames. (author)

  8. An improved multiple flame photometric detector for gas chromatography.

    Science.gov (United States)

    Clark, Adrian G; Thurbide, Kevin B

    2015-11-20

    An improved multiple flame photometric detector (mFPD) is introduced, based upon interconnecting fluidic channels within a planar stainless steel (SS) plate. Relative to the previous quartz tube mFPD prototype, the SS mFPD provides a 50% reduction in background emission levels, an orthogonal analytical flame, and easier more sensitive operation. As a result, sulfur response in the SS mFPD spans 4 orders of magnitude, yields a minimum detectable limit near 9×10(-12)gS/s, and has a selectivity approaching 10(4) over carbon. The device also exhibits exceptionally large resistance to hydrocarbon response quenching. Additionally, the SS mFPD uniquely allows analyte emission monitoring in the multiple worker flames for the first time. The findings suggest that this mode can potentially further improve upon the analytical flame response of sulfur (both linear HSO, and quadratic S2) and also phosphorus. Of note, the latter is nearly 20-fold stronger in S/N in the collective worker flames response and provides 6 orders of linearity with a detection limit of about 2.0×10(-13)gP/s. Overall, the results indicate that this new SS design notably improves the analytical performance of the mFPD and can provide a versatile and beneficial monitoring tool for gas chromatography. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Natural gas jet flames. Topical report, January 1994-August 1995

    Energy Technology Data Exchange (ETDEWEB)

    Atallah, S.; Saxena, S.K.

    1995-08-15

    Several incidents have been reported where high pressure natural gas transmission pipelines were ruptured and the escaping gas jet ignited. It was desired to estimate the length of the ensuing jet flame. Data on large scale jet fires were collected from accidents investigated by the National Transportation Safety Board, large-scale experiments on natural gas and LPG and from observations made during the Kuwaiti oil well fires. Analytical models which predict the size of jet flames were assembled and each model was evaluated against these data. A theoretical model developed by Kalghatgi at Shell, which most closely predicted the collected data, was selected and programmed for use on a PC. In addition, a simple empirical correlation similar to API`s flare correlation was developed by the authors for application to natural gas jet flames.

  10. Observations of Inland Snowpack-driven Bromine Chemistry near the Brooks Range, Alaska

    Science.gov (United States)

    Peterson, P.; Pöhler, D.; Sihler, H.; Zielcke, J.; S., General; Friess, U.; Platt, U.; Simpson, W. R.; Nghiem, S. V.; Shepson, P. B.; Stirm, B. H.; Pratt, K.

    2017-12-01

    The snowpack produces high amounts of reactive bromine in the polar regions during spring. The resulting atmospheric bromine chemistry depletes boundary layer ozone to near-zero levels and alters oxidation of atmospheric pollutants, particularly elemental mercury. To improve our understanding of the spatial extent of this bromine chemistry in Arctic coastal regions, the Purdue Airborne Laboratory for Atmospheric Research (ALAR), equipped with the Heidelberg Imaging differential optical absorption spectroscopy (DOAS) instrument, measured the spatial distribution of BrO, an indicator of active bromine chemistry, over northern Alaska during the March 2012 BRomine Ozone Mercury Experiment (BROMEX). Here we show that this bromine chemistry, commonly associated with snow-covered sea ice regions in the Arctic Ocean, is active 200 km inland in the foothills of the Brooks Range. Profiles retrieved from limb-viewing measurements show this event was located near the snowpack surface, with measured BrO mole ratios of 20 pmol mol-1 in a 500 m thick layer. This observed bromine chemistry is likely enabled by deposition of transported sea salt aerosol or gas phase bromine species from prior activation events to the snowpack. These observations of halogen activation hundreds of km from the coast suggest the impacts of this springtime bromine chemistry are not restricted to sea ice regions and directly adjacent coastal regions.

  11. Photochemical reactions of brominated diphenylethers in organic solvents and adsorbed on silicon dioxide in aqueous suspension

    Energy Technology Data Exchange (ETDEWEB)

    Palm, W.U.; Kopetzky, R.; Sossinka, W.; Ruck, W. [Univ. of Lueneburg, Environmental Chemistry, Lueneburg (Germany); Zetzsch, C. [Univ. of Bayreuth, Atmos. Chem. Research, Bayreuth, and Fraunhofer-Inst. of Toxicology and Experimental Medicine, Hannover (Germany)

    2004-09-15

    Polybrominated diphenylethers (BDEs) are in use as flame retardants worldwide and are found as xenobiotics in environmental samples. Photolysis by sunlight, one of the potential abiotic degradation pathways, is found to be rapid in laboratory experiments, especially for deca-BDE, the most prominent BDE as compared to commercial penta- and octa-BDEs. Due to the extremely low water solubility of BDEs, these experiments were mostly performed in organic solvents so far, and a few in environmental matrices (sand and soil) and on dry and hydrated quartz glass. However, detailed UV absorption spectra of deca-BDE and debrominated BDEs in the relevant wavelength range above 300 nm have become available only recently, besides the UV maxima of a number of synthesized congeners at shorter wavelengths and an exploratory study from our laboratory. Other important parameters to assess the abiotic degradation in the environment, such as OH-rate constants and photolytic quantum yields of BDEs are not available. Furthermore, analysis of BDEs was mostly performed by GC-MS, and the capability of HPLC with a diode array detector (DAD) has not yet been exploited. This study presents kinetic results on the photolysis of BDEs in tetrahydrofuran (THF) with detailed photolytic pathways for a tetra-BDE (2,2'4,4'-BDE), a hexa-BDE (2,2'4,4',5,5'-BDE) and deca-BDE. Employing HPLC with a diode array detector (DAD) as analytical tool, quantum yields of BDEs with N{sub Br} = 1-10 are determined. Furthermore, the formation of brominated dibenzofurans (BDFs) was investigated. Since the environmental relevance of photolysis experiments in organic solvents is questionable, first results on photolysis of deca-BDE adsorbed on silicon dioxide particles, suspended in water, are presented.

  12. Research on flame retardation of wool fibers

    International Nuclear Information System (INIS)

    Enomoto, Ichiro; Ametani, Kazuo; Sawai, Takeshi

    1990-01-01

    Flame retardant, vinyl phosphonate oligomer, was uniformly impregnated in wool fibers, and by irradiating low energy electron beam or cobalt-60 gamma ray, the flame retardation of fabrics was attempted, as the results, the following knowledges were obtained. At the rate of sticking of flame retardant lower than that in cotton fabrics, sufficient flame retarding property can be given. The flame retarding property withstands 30 times of washing. The lowering of strength due to the processing hardly arose. For the flame retardation, gamma-ray was more effective than electron beam. Since the accidents of burning clothes have occurred frequently, their flame retardation has been demanded. So far the flame retardation of cotton fabrics has been advanced, but this time the research on the flame retardation of wool fabrics was carried out by the same method. The experimental method is explained. As for the performance of the processed fabrics, the rate of sticking of the flame retardant, the efficiency of utilization, the flame retarding property, the endurance in washing and the tensile and tearing strength were examined. As the oxygen index was higher, the flame retarding property was higher, and in the case of the index being more than 27, the flame retarding property is sufficient, that is, the rate of sticking of 6% in serge and 5% in muslin. (K.I.)

  13. Inorganic bromine in the marine boundary layer: a critical review

    Directory of Open Access Journals (Sweden)

    R. Sander

    2003-01-01

    Full Text Available The cycling of inorganic bromine in the marine boundary layer (mbl has received increased attention in recent years. Bromide, a constituent of sea water, is injected into the atmosphere in association with sea-salt aerosol by breaking waves on the ocean surface. Measurements reveal that supermicrometer sea-salt aerosol is substantially depleted in bromine (often exceeding 50% relative to conservative tracers, whereas marine submicrometer aerosol is often enriched in bromine. Model calculations, laboratory studies, and field observations strongly suggest that the supermicrometer depletions reflect the chemical transformation of particulate bromide to reactive inorganic gases that influence the processing of ozone and other important constituents of marine air. Mechanisms for the submicrometer enrichments are not well understood. Currently available techniques cannot reliably quantify many Br containing compounds at ambient concentrations and, consequently, our understanding of inorganic Br cycling over the oceans and its global significance are uncertain. To provide a more coherent framework for future research, we have reviewed measurements in marine aerosol, the gas phase, and in rain. We also summarize sources and sinks, as well as model and laboratory studies of chemical transformations. The focus is on inorganic bromine over the open oceans outside the polar regions. The generation of sea-salt aerosol at the ocean surface is the major tropospheric source producing about 6.2 Tg/a of bromide. The transport of Br from continents (as mineral aerosol, and as products from biomass-burning and fossil-fuel combustion can be of local importance. Transport of degradation products of long-lived Br containing compounds from the stratosphere and other sources contribute lesser amounts. Available evidence suggests that, following aerosol acidification, sea-salt bromide reacts to form Br2 and BrCl that volatilize to the gas phase and photolyze in daylight

  14. Analysis of the flamelet concept in the numerical simulation of laminar partially premixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Consul, R.; Oliva, A.; Perez-Segarra, C.D.; Carbonell, D. [Centre Tecnologic de Transferencia de Calor (CTTC), Universitat Politecnica de Catalunya (UPC), Colom 11, E-08222, Terrassa, Barcelona (Spain); de Goey, L.P.H. [Eindhoven University of Technology, Department of Mechanical Engineering, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2008-04-15

    The aim of this work is to analyze the application of flamelet models based on the mixture fraction variable and its dissipation rate to the numerical simulation of partially premixed flames. Although the main application of these models is the computation of turbulent flames, this work focuses on the performance of flamelet concept in laminar flame simulations removing, in this way, turbulence closure interactions. A well-known coflow methane/air laminar flame is selected. Five levels of premixing are taken into account from an equivalence ratio {phi}={infinity} (nonpremixed) to {phi}=2.464. Results obtained using the flamelet approaches are compared to data obtained from the detailed solution of the complete transport equations using primitive variables. Numerical simulations of a counterflow flame are also presented to support the discussion of the results. Special emphasis is given to the analysis of the scalar dissipation rate modeling. (author)

  15. Flame visualization in power stations

    Energy Technology Data Exchange (ETDEWEB)

    Hulshof, H J.M.; Thus, A W; Verhage, A J.L. [KEMA Fossil Generation, Arnhem (Netherlands)

    1994-01-01

    The study on the title subject is aimed at the determination of the form of the flame and the radiation temperature of the flames of the burners in electric power plants. The adjustment of the burners in a boiler is assessed on the basis of the total performance, in which the NO[sub x]- and CO-concentrations in the flue gases are normative. By comparing the burners mutually, deviating adjustments can be observed, applying optical monitoring techniques. Measurements have been carried out of the coal flames in the unit Gelderland13 of the Dutch energy production company EPON and of the gas flames at the Claus plant A and B of the Dutch energy company EPZ. The final aim of the title study is to draft guidelines, based on the measured flame data, by means of which for every individual burner the adjustment of the fuel supply, the relation with the air supply and the swirl of the combustion air can be optimized

  16. Role of the outer-edge flame on flame extinction in nitrogen-diluted non-premixed counterflow flames with finite burner diameters

    KAUST Repository

    Chung, Yong Ho

    2013-03-01

    This study of nitrogen-diluted non-premixed counterflow flames with finite burner diameters investigates the important role of the outer-edge flame on flame extinction through experimental and numerical analyses. It explores flame stability diagrams mapping the flame extinction response of nitrogen-diluted non-premixed counterflow flames to varying global strain rates in terms of burner diameter, burner gap, and velocity ratio. A critical nitrogen mole fraction exists beyond which the flame cannot be sustained; the critical nitrogen mole fraction versus global strain rate curves have C-shapes for various burner diameters, burner gaps, and velocity ratios. At sufficiently high strain-rate flames, these curves collapse into one curve; therefore, the flames follow the one-dimensional flame response of a typical diffusion flame. Low strain-rate flames are significantly affected by radial conductive heat loss, and therefore flame length. Three flame extinction modes are identified: flame extinction through shrinkage of the outer-edge flame with or without oscillations at the outer-edge flame prior to the extinction, and flame extinction through a flame hole at the flame center. The extinction modes are significantly affected by the behavior of the outer-edge flame. Detailed explanations are provided based on the measured flame-surface temperature and numerical evaluation of the fractional contribution of each term in the energy equation. Radial conductive heat loss at the flame edge to ambience is the main mechanism of extinction through shrinkage of the outer-edge flame in low strain-rate flames. Reduction of the burner diameter can extend the flame extinction mode by shrinking the outer-edge flame in higher strain-rate flames. © 2012 Elsevier Ltd. All rights reserved.

  17. Flame Retardants Used in Flexible Polyurethane Foam

    Science.gov (United States)

    The partnership project on flame retardants in furniture seeks to update the health and environmental profiles of flame-retardant chemicals that meet fire safety standards for upholstered consumer products with polyurethane foam

  18. Flame retardant treatments of PBI fabric.

    Science.gov (United States)

    Temin, S. C.

    1972-01-01

    Fabrics knitted or woven from polybenzimidazole (PBI) fibers were treated to reduce flammability in oxygen atmospheres, particularly that of 5 psia oxygen. Bromination to approximately 15% weight gain of such fabrics led to markedly lower burning rates; samples brominated to over 80% weight gain were self-extinguishing in 5 psia oxygen. The loss in tensile strength of fabrics due to bromination was negligible although shrinkage was observed. Free fibers showed negligible losses on bromination. Treatment of PBI fabric with organophosphorus compounds also achieved self-extinguishing character in 5 psia oxygen but the enhanced flameproofing was largely lost on leaching. Reaction with POCl3 in pyridine led to a permanent reduction in flammability.

  19. Superior bactericidal activity of N-bromine compounds compared to their N-chlorine analogues can be reversed under protein load.

    Science.gov (United States)

    Gottardi, W; Klotz, S; Nagl, M

    2014-06-01

    To investigate and compare the bactericidal activity (BA) of active bromine and chlorine compounds in the absence and presence of protein load. Quantitative killing tests against Escherichia coli and Staphylococcus aureus were performed both in the absence and in the presence of peptone with pairs of isosteric active chlorine and bromine compounds: hypochlorous and hypobromous acid (HOCl and HOBr), dichloro- and dibromoisocyanuric acid, chlorantine and bromantine (1,3-dibromo- and 1,3 dichloro-5,5-dimethylhydantoine), chloramine T and bromamine T (N-chloro- and N-bromo-4-methylbenzenesulphonamide sodium), and N-chloro- and N-bromotaurine sodium. To classify the bactericidal activities on a quantitative basis, an empirical coefficient named specific bactericidal activity (SBA), founded on the parameters of killing curves, was defined: SBA= mean log reductions/(mean exposure times x concentration) [mmol 1(-1) min (-1)]. In the absence of peptone, tests with washed micro-organisms revealed a throughout higher BA of bromine compounds with only slight differences between single substances. This was in contrast to chlorine compounds, whose killing times differed by a factor of more than four decimal powers. As a consequence, also the isosteric pairs showed according differences. In the presence of peptone, however, bromine compounds showed an increased loss of BA, which partly caused a reversal of efficacy within isosteric pairs. In medical practice, weakly oxidizing active chlorine compounds like chloramines have the highest potential as topical anti-infectives in the presence of proteinaceous material (mucous membranes, open wounds). Active bromine compounds, on the other hand, have their chance at insensitive body regions with low organic matter, for example skin surfaces. The expected protein load is one of the most important parameters for selection of a suited active halogen compound. © 2014 The Society for Applied Microbiology.

  20. Speciation of the bio-available iodine and bromine forms in edible seaweed by high performance liquid chromatography hyphenated with inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Romarís-Hortas, Vanessa; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Jorge; Moreda-Piñeiro, Antonio

    2012-01-01

    Highlights: ► Bioavailable iodine and bromine speciation in edible seaweed were developed. ► In vitro dialyzability was used to assess the bioavailable fractions. ► AEC hyphenated with inductively coupled plasma-mass spectrometry was used. ► Iodide, MIT, DIT, bromide and bromate were found in dialyzates from edible seaweed. ► Positive correlation between bioavailability and protein contents was found. - Abstract: A bioavailability study based on an in vitro dialyzability approach has been applied to assess the bio-available fractions of iodine and bromine species from edible seaweed. Iodide, iodate, 3-iodo-tyrosine (MIT), 3,5-diiodo-tyrosine (DIT), bromide and bromate were separated by anion exchange chromatography under a gradient elution mode (175 mM ammonium nitrate plus 15% (v/v) methanol, pH 3.8, as a mobile phase, and flow rates within the 0.5–1.5 mL min −1 range). Inductively coupled plasma-mass spectrometry (ICP-MS) was used as a selective detector for iodine ( 127 I) and bromine ( 79 Br). Low dialyzability ratios (within the 2.0–18% range) were found for iodine species; whereas, moderate dialyzability percentages (from 9.0 to 40%) were obtained for bromine species. Iodide and bromide were the major species found in the dialyzates from seaweed, although MIT and bromate were also found in the dialyzates from most of the seaweed samples analysed. However, DIT was only found in dialyzates from Wakame, Kombu, and NIES 09 (Sargasso) certified reference material; whereas, iodate was not found in any dialyzate. Iodine dialyzability was found to be dependent on the protein content (negative correlation), and on the carbohydrate and dietary fibre levels (positive correlation). However, bromine dialyzability was only dependent on the protein amount in seaweed (negative correlation).

  1. Experiment and Simulation of Autoignition in Jet Flames and its Relevance to Flame Stabilization and Structure

    KAUST Repository

    Al-Noman, Saeed M.

    2016-01-01

    temperature coflow air were studied numerically. Several flame configurations were investigated by varying the initial temperature and fuel mole fraction. Characteristics of chemical kinetics structures for autoignited lifted flames were discussed based on the kinetic structures of homogeneous autoignition and flame propagation of premixed mixtures. Results showed that for autoignited lifted flame with tribrachial structure, a transition from autoignition to flame propagation modes occurs for reasonably stoichiometric mixtures. Characteristics of Mild combustion can be treated as an autoignited lean premixed lifted flame. Transition behavior from Mild combustion to a nozzle-attached flame was also investigated by increasing the fuel mole fraction.

  2. Flame emission, atomic absorption and fluorescence spectrometry

    International Nuclear Information System (INIS)

    Horlick, G.

    1980-01-01

    Six hundred and thirty references are cited in this review. The information in the review is divided into 12 major areas: books, reviews, and bibliographies; fundamental studies in flames; developments in instrumentation; measurement techniques and procedure; flame emission spectrometry; flame atomic absorption spectrometry; flame molecular absorption spectrometry; electrothermal atomization atomic absorption spectroscopy; hydride generation techniques; graphite furnace atomic emission spectrometry; atomic fluorescence spectrometry; and analytical comparisons

  3. Identification of the flame retardant decabromodiphenyl ethane in the environment.

    Science.gov (United States)

    Kierkegaard, Amelie; Björklund, Jonas; Fridén, Ulrika

    2004-06-15

    The brominated flame retardant decabromodiphenyl ethane, DeBDethane, is marketed as an alternative to decabromodiphenyl ether, BDE209. There are currently no data available about the presence of DeBDethane in the environment. In this study, DeBDethane was positively identified by high-resolution mass spectrometry and quantified by low-resolution mass spectrometry with electron capture negative ionization in sewage sludge, sediment, and indoor air. It was found in 25 of the 50 Swedish sewage treatment plants investigated, with estimated levels up to about 100 ng/g dry weight. The concentration of DeBDethane in sediment from Western Scheldt in The Netherlands was 24 ng/g dry weight, and in an air sample from a Swedish electronics dismantling facility it was 0.6 ng/m3. DeBDethane was also found together with nonabromodiphenyl ethanes in water piping insulation. All samples contained BDE209 in higher concentrations as compared to DeBDethane (DeBDethane/BDE209 ratios ranging from 0.02 to 0.7), probably reflecting the higher and longer usage of BDE209. There is an ongoing risk assessment within the European Union regarding BDE209. Since DeBDethane has similar applications, it is important to investigate its environmental behavior before using it to replace BDE209.

  4. Preparation of candidate reference materials for the determination of phosphorus containing flame retardants in styrene-based polymers.

    Science.gov (United States)

    Roth, Thomas; Urpi Bertran, Raquel; Latza, Andreas; Andörfer-Lang, Katrin; Hügelschäffer, Claudia; Pöhlein, Manfred; Puchta, Ralph; Placht, Christian; Maid, Harald; Bauer, Walter; van Eldik, Rudi

    2015-04-01

    Candidate reference materials (RM) for the analysis of phosphorus-based flame retardants in styrene-based polymers were prepared using a self-made mini-extruder. Due to legal requirements of the current restriction for the use of certain hazardous substances in electrical and electronic equipment, focus now is placed on phosphorus-based flame retardants instead of the brominated kind. Newly developed analytical methods for the first-mentioned substances also require RMs similar to industrial samples for validation and verification purposes. Hence, the prepared candidate RMs contained resorcinol-bis-(diphenyl phosphate), bisphenol A bis(diphenyl phosphate), triphenyl phosphate and triphenyl phosphine oxide as phosphorus-based flame retardants. Blends of polycarbonate and acrylonitrile-co-butadiene-co-styrene as well as blends of high-impact polystyrene and polyphenylene oxide were chosen as carrier polymers. Homogeneity and thermal stability of the candidate RMs were investigated. Results showed that the candidate RMs were comparable to the available industrial materials. Measurements by ICP/OES, FTIR and NMR confirmed the expected concentrations of the flame retardants and proved that analyte loss and degradation, respectively, was below the uncertainty of measurement during the extrusion process. Thus, the candidate RMs were found to be suitable for laboratory use.

  5. Removal of pharmaceuticals, polybrominated flame retardants and UV-filters from sludge by the fungus Trametes versicolor in bioslurry reactor

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Rodriguez, Carlos E. [Unitat Asociada de Biocatalisi Aplicada IQAC-CSIC, Escola d' Enginyeria, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Centro de Investigacion en Contaminacion Ambiental, Universidad de Costa Rica, 2060 San Jose (Costa Rica); Baron, Enrique; Gago-Ferrero, Pablo; Jelic, Aleksandra; Llorca, Marta; Farre, Marinella; Diaz-Cruz, M. Silvia; Eljarrat, Ethel [Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain); Petrovic, Mira [Institucio Catalana de Reserca i Estudis Avancats (ICREA), Passeig Lluis Companys 23, 80010 Barcelona (Spain); Catalan Institute for Water Research (ICRA), H2O Building, Scientific and Technological Park of the University of Girona, 101-E-17003 Girona (Spain); Caminal, Gloria, E-mail: Gloria.Caminal@uab.cat [Unitat Asociada de Biocatalisi Aplicada IQAC-CSIC, Escola d' Enginyeria, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Barcelo, Damia [Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain); Catalan Institute for Water Research (ICRA), H2O Building, Scientific and Technological Park of the University of Girona, 101-E-17003 Girona (Spain); King Saud University (KSU), P.O. Box 2455, 11451 Riyadh (Saudi Arabia); and others

    2012-09-30

    Highlights: Black-Right-Pointing-Pointer Sludge from a WWTP was treated in a fungal slurry reactor with Trametes versicolor. Black-Right-Pointing-Pointer Twenty-four pharmaceuticals were removed at important extents. Black-Right-Pointing-Pointer UV-filters and brominated flame retardants were also degraded. Black-Right-Pointing-Pointer Overall toxicity of sludge increased despite the pollutant removal. - Abstract: Conventional wastewater treatments are inefficient in the removal of many organic pollutants. The presence of these contaminants in the final sludge represents a source of environmental pollution due to the increasing use of biosolids in land application. A biotechnological approach which employed the fungus Trametes versicolor in a sludge-bioslurry reactor was assessed in order to remove several groups of emerging pollutants. Biological fungal activity was monitored by means of ergosterol and laccase determinations. Fifteen out of 24 detected pharmaceuticals were removed at efficiencies over 50% after the treatment, including eight completely degraded. Removal ranged between 16-53% and 22-100% for the brominated flame retardants and the UV-filters, respectively. Only two of all the detected compounds remained unchanged after the treatment. Although elimination results are promising, the toxicity of the final sludge increased after the treatment. This finding is contrary to the toxicity results obtained in similar treatments of sludge with T. versicolor in solid-phase.

  6. Removal of pharmaceuticals, polybrominated flame retardants and UV-filters from sludge by the fungus Trametes versicolor in bioslurry reactor

    International Nuclear Information System (INIS)

    Rodríguez-Rodríguez, Carlos E.; Barón, Enrique; Gago-Ferrero, Pablo; Jelić, Aleksandra; Llorca, Marta; Farré, Marinella; Díaz-Cruz, M. Silvia; Eljarrat, Ethel; Petrović, Mira; Caminal, Glòria; Barceló, Damià

    2012-01-01

    Highlights: ► Sludge from a WWTP was treated in a fungal slurry reactor with Trametes versicolor. ► Twenty-four pharmaceuticals were removed at important extents. ► UV-filters and brominated flame retardants were also degraded. ► Overall toxicity of sludge increased despite the pollutant removal. - Abstract: Conventional wastewater treatments are inefficient in the removal of many organic pollutants. The presence of these contaminants in the final sludge represents a source of environmental pollution due to the increasing use of biosolids in land application. A biotechnological approach which employed the fungus Trametes versicolor in a sludge-bioslurry reactor was assessed in order to remove several groups of emerging pollutants. Biological fungal activity was monitored by means of ergosterol and laccase determinations. Fifteen out of 24 detected pharmaceuticals were removed at efficiencies over 50% after the treatment, including eight completely degraded. Removal ranged between 16–53% and 22–100% for the brominated flame retardants and the UV-filters, respectively. Only two of all the detected compounds remained unchanged after the treatment. Although elimination results are promising, the toxicity of the final sludge increased after the treatment. This finding is contrary to the toxicity results obtained in similar treatments of sludge with T. versicolor in solid-phase.

  7. 30 CFR 14.20 - Flame resistance.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Flame resistance. 14.20 Section 14.20 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF... § 14.20 Flame resistance. Conveyor belts for use in underground coal mines must be flame-resistant and...

  8. TURBULENT OXYGEN FLAMES IN TYPE Ia SUPERNOVAE

    International Nuclear Information System (INIS)

    Aspden, A. J.; Bell, J. B.; Woosley, S. E.

    2011-01-01

    In previous studies, we examined turbulence-flame interactions in carbon-burning thermonuclear flames in Type Ia supernovae. In this study, we consider turbulence-flame interactions in the trailing oxygen flames. The two aims of the paper are to examine the response of the inductive oxygen flame to intense levels of turbulence, and to explore the possibility of transition to detonation in the oxygen flame. Scaling arguments analogous to the carbon flames are presented and then compared against three-dimensional simulations for a range of Damkoehler numbers (Da 16 ) at a fixed Karlovitz number. The simulations suggest that turbulence does not significantly affect the oxygen flame when Da 16 16 >1, turbulence enhances heat transfer and drives the propagation of a flame that is narrower than the corresponding inductive flame would be. Furthermore, burning under these conditions appears to occur as part of a combined carbon-oxygen turbulent flame with complex compound structure. The simulations do not appear to support the possibility of a transition to detonation in the oxygen flame, but do not preclude it either.

  9. Hysteresis and transition in swirling nonpremixed flames

    NARCIS (Netherlands)

    Tummers, M.J.; Hübner, A.W.; van Veen, E.H.; Hanjalic, K.; van der Meer, Theodorus H.

    2009-01-01

    Strongly swirling nonpremixed flames are known to exhibit a hysteresis when transiting from an attached long, sooty, yellow flame to a short lifted blue flame, and vice versa. The upward transition (by increasing the air and fuel flow rates) corresponds to a vortex breakdown, i.e. an abrupt change

  10. Experimental characterization of methane inverse diffusion flame

    KAUST Repository

    Elbaz, Ayman M.

    2014-06-26

    This article presents 10-kHz images of OH-PLIF simultaneously with 2-D PIV measurements in an inverse methane diffusion flame. Under a constant fuel flow rate, the central air jet Re was varied, leading to air to fuel velocity ratio, Vr, to vary from 8.3 to 66.5. Starting from Vr = 20.7, the flame is commonly characterized by three distinct zones. The length of the lower fuel entrainment region is inversely proportional to Vr. The flames investigated resemble a string shear layer confining this zone, and converging into the second distinct region, the flame neck zone. The third region is the rest of the flame, which spreads in a jet-like manner. The inverse diffusion flames exhibit varying degrees of partial premixing, depending upon on the velocity ratio Vr, and this region of partial premixing evolves into a well-mixed reaction zone along the flame centerline. The OH distribution correlated with the changes in the mean characteristics of the flow through reduction in the local Reynolds number due to heat release. The existence of a flame suppresses or laminarizes the turbulence at early axial locations and promotes fluctuations at the flame tip for flames with Vr < 49.8. In addition, the flame jet width can be correlated to the OH distribution. In upstream regions of the flames, the breaks in OH are counterbalanced by flame closures and are governed by edge flame propagation. These local extinctions were found to occur at locations where large flow structures were impinging on the flame and are associated with a locally higher strain rate or correlated to the local high strain rates at the flame hole edges without this flow impinging. Another contributor to re-ignition was found to be growing flame kernels. As the flames approach global blow-off, these kernels become the main mechanism for re-ignition further downstream of the flames. At low Vr, laminarization within the early regions of the flame provides an effective shield, preventing the jet flow from

  11. Distribution of bromine in mixed iodide-bromide organolead perovskites and its impact on photovoltaic performance

    NARCIS (Netherlands)

    Zhou, Yang; Wang, Feng; Fang, Hong-Hua; Loi, Maria Antonietta; Xie, Fang-Yan; Zhao, Ni; Wong, Ching-Ping

    2016-01-01

    Mixed iodide-bromide (I-Br) organolead perovskites are of great interest for both single junction and tandem solar cells since the optical bandgap of the materials can be tuned by varying the bromine to iodine ratio. Yet, it remains unclear how bromine incorporation modifies the properties of the

  12. Control of fouling organisms in estuarine cooling water systems by chlorine and bromine chloride

    International Nuclear Information System (INIS)

    Burton, D.T.; Margrey, S.L.

    1979-01-01

    The study described was initiated to evaluate the antifouling effectiveness of chlorine and bromine chloride in low velocity flow areas where estuarine waters are used for cooling purposes. The relative antifouling effectiveness of chlorine and bromine chloride under intermittent and continuous modes of application in low velocity flow areas was evaluated at an estuarine power plant located on the Chesapeake Bay

  13. A Multistep Synthesis Incorporating a Green Bromination of an Aromatic Ring

    Science.gov (United States)

    Cardinal, Pascal; Greer, Brandon; Luong, Horace; Tyagunova, Yevgeniya

    2012-01-01

    Electrophilic aromatic substitution is a fundamental topic taught in the undergraduate organic chemistry curriculum. A multistep synthesis that includes a safer and greener method for the bromination of an aromatic ring than traditional bromination methods is described. This experiment is multifaceted and can be used to teach students about…

  14. Obtaining the Iodine Value of Various Oils via Bromination with Pyridinium Tribromide

    Science.gov (United States)

    Simurdiak, Michael; Olukoga, Olushola; Hedberg, Kirk

    2016-01-01

    A laboratory exercise was devised that allows students to rapidly and fairly accurately determine the iodine value of oleic acid. This method utilizes the addition of elemental bromine to the unsaturated bonds in oleic acid, due to bromine's relatively fast reaction rate compared to that of the traditional Wijs solution method. This method also…

  15. New fast organic scintillators using intramolecular bromine quenching

    International Nuclear Information System (INIS)

    Berlman, I.B.; Lutz, S.S.; Flournoy, J.M.; Ashford, C.B.; Franks, L.A.

    1984-01-01

    Organic scintillator solutions with decay times as fast as 500 ps and with relatively high conversion efficiencies have been developed. The intramolecular quenching was achieved through the novel approach of adding a bromine atom to the 3- or 4-position of para-oligophenylenes, the fluorescent solutes in these binary solutions. The bromine serves to enhance singlet-to-triplet intersystem crossing in the chromophore, causing a reduction in the scintillation yield and a concomitant reduction in the decay time. The very fast value given above probably also involves some intermolecular self-quenching at high concentration. In addition, the bromine reduces the symmetry of the molecules, thereby increasing their solubility. Finally, an alkyl chain on the opposite para position further increases the solubility and also increases the immunity of the chromophore to quenching. The decay times for binary liquid solutions in toluene (at the indicated concentrations) were 0.51 ns for 4-BHTP (0.14 M), 0.75 ns for 3-BHTP (0.14 M), 0.57 ns for 3-BTP (0.14 M), and 1.3 ns for 4-BHQP (0.06 M). Binary plastics with 4-BHTP as the solute in concentrations up to 0.14 M were cast in polystyrene. The shortest decay time, 0.40 ns, was measured for the 0.14 M concentration. A plastic scintillator containing 3-BTP (0.11 M in polystyrene) had a decay time of 0.85 ns. These results compare favorably with the plastic scintillator BC-422 whose decay time is about 1.4 ns. (orig./HSI)

  16. Theoretical performance of hydrogen-bromine rechargeable SPE fuel cell

    Science.gov (United States)

    Savinell, Robert F.; Fritts, S. D.

    1987-01-01

    A mathematical model was formulated to describe the performance of a hydrogen-bromine fuel cell. Porous electrode theory was applied to the carbon felt flow-by electrode and was coupled to theory describing the solid polymer electrolyte (SPE) system. Parametric studies using the numerical solution to this model were performed to determine the effect of kinetic, mass transfer, and design parameters on the performance of the fuel cell. The results indicate that the cell performance is most sensitive to the transport properties of the SPE membrane. The model was also shown to be a useful tool for scale-up studies.

  17. Deriving an atmospheric budget of total organic bromine using airborne in-situ measurements of brominated hydrocarbons in the Western Pacific during SHIVA

    Science.gov (United States)

    Sala, Stephan; Bönisch, Harald; Keber, Timo; Oram, Dave; Mills, Graham; Engel, Andreas

    2014-05-01

    Halogenated hydrocarbons play a major role as precursors for stratospheric ozone depletion. Released from the surface in the troposphere, the halocarbons reach the stratosphere via transport through the tropical tropopause layer. The contribution of the so called very short lived species (VSLS), having atmospheric lifetimes of less than half a year as sources gases for stratospheric bromine is significant. Source gas observations of long-lived bromine compounds and VSLS have so far not been able to explain the amount of bromine derived in the stratosphere from observations of BrO and modeling of the ratio of BrO to total bromine. Due to the short lifetimes and the high atmospheric variability, the representativeness of the available observations of VSLS source gases remains unclear, as these may vary with region and display seasonal variability. During the SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) project an extensive dataset with over 700 samples of ambient air of all halogen species relevant for the atmospheric budget of total organic bromine (long lived halocarbons: H-1301, H-1211, H-1202, H-2402 and CH3Br, very short lived substances: CHBr3, CH2Br2, CHBr2Cl, CHBrCl2 and CHBrCl) have been collected from onboard the FALCON aircraft in the West Pacific region. Measurements were performed with the newly developed fully-automated in-situ instrument GHOST-MS (Gas chromatograph for the Observation of Tracers - coupled with a Mass Spectrometer) by the Goethe University of Frankfurt and with the onboard whole-air sampler WASP with subsequent ground based state-of-the-art GC/MS analysis by the University of East Anglia. We will present the datasets, compare these to other observation, derive a bromine budget for the West Pacific and derive an estimate of the amount of bromine from VSLS reaching the stratosphere. Using the mean mixing ratios in the upper troposphere of the halocarbons mentioned above, the calculated budget of the total organic

  18. Research on the phenomenon of graphitization. Crystallographic study - Study of bromine sorption

    International Nuclear Information System (INIS)

    Maire, Jacques

    1967-01-01

    This research thesis reports the study of the mechanism of graphitization of carbon by using X-ray diffraction analysis and the physical and chemical study of lamellar reactions between carbon and bromine. The author first presents generalities and results of preliminary studies (meaning of graphitization, presentation of the various carbon groups and classes), and then reports the study of the graphitization of compact carbons (soft carbons). More precisely, he reports the crystallographic study of partially graphitized carbons: methods and principles, experimental results and their analysis, discussion of the graphitization mechanism. In the next part, the author reports the study of bromine sorption on carbons: experimental method, isotherms of a natural graphite and of a graphitized carbon, structure of carbon-bromine complexes, isotherms of graphitizable carbons and of all other carbons, distribution of bromine layers in partially graphitized carbons, bromine sorption and Fermi level

  19. Effects of bromine on mitosis in root-tips of Allium cepa

    Energy Technology Data Exchange (ETDEWEB)

    Chury, J; Slouka, V

    1949-01-01

    The root-tips of Allium cepa, 1.5-2 cm. long, were exposed to pure bromine vapor for five minutes. The root-tips were then washed for ten minutes in water, and kept in fresh-water at a temperature of 20-24/sup 0/C. Squash preparations were made and stained according to the method of Darlington and La Cour. Bromine acting for five minutes on the root-tips of Allium has a specific effect on the cell nucleus in the resting stage. The effects induced are shown thirty-six hours after treatment by spindle abnormalities in metaphase and anaphase, and result in polyploidy in a large number of cells. Bromine produces chromosome and chromatid fragmentation; the latter may be followed by reunion. The effect of the bromine is cumulative and depends on the time which elapses between treatment and fixation. The cytological effects induced by bromine strongly suggest that it is another specific mutafacient chemical.

  20. Labeling of receptor ligands with bromine radionuclides. Progress report, March 1, 1981-February 28, 1982

    International Nuclear Information System (INIS)

    Welch, M.J.

    1981-10-01

    In recent years there has been an interest in the use of various radioisotopes of bromine as labels for radiopharmaceuticals. Although radioisotopes of iodine have been used extensively as radiopharmaceutical labels, there are several advantages associated with the use of radiobromine as a label, due primarily to increased stability of bonds to the radiohalide and smaller steric perturbation resulting from substitution of the radiohalide. Methods of attaching radiobromine to receptor ligands with the potential of mapping estrogen receptors in mammary tumors and uteri were studied. Two ligands were studied extensively in vitro and in animal models; preliminary studies were also carried out in humans. To date, the only radioisotope of bromine used was bromine-77. In addition, a series of model compounds were labeled with bromine-77 using a recently described method for rapid bromination; the scope and limitations of this new rapid radiobromination technique were evaluated

  1. The VLT FLAMES Tarantula Survey

    NARCIS (Netherlands)

    Evans, C.; Taylor, W.; Sana, H.; Hénault-Brunet, V.; Bagnoli, T.; Bastian, N.; Bestenlehner, J.; Bonanos, A.; Bressert, E.; Brott, I.; Campbell, M.; Cantiello, M.; Carraro, G.; Clark, S.; Costa, E.; Crowther, P.; de Koter, A.; de Mink, S.; Doran, E.; Dufton, P.; Dunstall, P.; Garcia, M.; Gieles, M.; Gräfener, G.; Herrero, A.; Howarth, I.; Izzard, R.; Köhler, K.; Langer, N.; Lennon, D.; Maíz Apellániz, J.; Markova, N.; Najarro, P.; Puls, J.; Ramirez, O.; Sabín-Sanjulián, C.; Simón-Díaz, S.; Smartt, S.; Stroud, V.; van Loon, J.; Vink, J.S.; Walborn, N.

    2011-01-01

    We introduce the VLT FLAMES Tarantula Survey, an ESO Large Programme from which we have obtained optical spectroscopy of over 800 massive stars in the spectacular 30 Doradus region of the Large Magellanic Cloud. A key feature is the use of multi-epoch observations to provide strong constraints on

  2. Flex-flame burner and combustion method

    Science.gov (United States)

    Soupos, Vasilios; Zelepouga, Serguei; Rue, David M.; Abbasi, Hamid A.

    2010-08-24

    A combustion method and apparatus which produce a hybrid flame for heating metals and metal alloys, which hybrid flame has the characteristic of having an oxidant-lean portion proximate the metal or metal alloy and having an oxidant-rich portion disposed above the oxidant lean portion. This hybrid flame is produced by introducing fuel and primary combustion oxidant into the furnace chamber containing the metal or metal alloy in a substoichiometric ratio to produce a fuel-rich flame and by introducing a secondary combustion oxidant into the furnace chamber above the fuel-rich flame in a manner whereby mixing of the secondary combustion oxidant with the fuel-rich flame is delayed for a portion of the length of the flame.

  3. Simulation of flame surface density and burning rate of a premixed turbulent flame using contour advection

    Energy Technology Data Exchange (ETDEWEB)

    Tang, B.H.Y.; Chan, C.K. [Department of Applied Mathematics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

    2006-10-15

    In this paper, a 2-dimensional rod-stabilized V-shaped flame is simulated using contour advection with surgery as well as the random vortex method. Effects of turbulence on various quantities, such as flame brush thickness and flame surface density, are investigated. The flame surface density S is estimated using the Bray-Moss-Libby formulation, which involves the use of a mean orientation factor {sigma}{sub c}. As a comparison, values of S are also obtained using Shepherd's model, which employs the values of mean flame surface area and mean flame length. Local flame structure is characterized in terms of turbulent flame brush, orientation factor, and flame surface density. Profiles of S obtained using the two different models are compared and show that discrepancy is more evident with increasing turbulence intensity. (author)

  4. A flame particle tracking analysis of turbulence–chemistry interaction in hydrogen–air premixed flames

    KAUST Repository

    Uranakara, Harshavardhana A.; Chaudhuri, Swetaprovo; Dave, Himanshu L.; Arias, Paul G.; Im, Hong G.

    2015-01-01

    Interactions of turbulence, molecular transport, and energy transport, coupled with chemistry play a crucial role in the evolution of flame surface geometry, propagation, annihilation, and local extinction/re-ignition characteristics of intensely turbulent premixed flames. This study seeks to understand how these interactions affect flame surface annihilation of lean hydrogen–air premixed turbulent flames. Direct numerical simulations (DNSs) are conducted at different parametric conditions with a detailed reaction mechanism and transport properties for hydrogen–air flames. Flame particle tracking (FPT) technique is used to follow specific flame surface segments. An analytical expression for the local displacement flame speed (Sd) of a temperature isosurface is considered, and the contributions of transport, chemistry, and kinematics on the displacement flame speed at different turbulence-flame interaction conditions are identified. In general, the displacement flame speed for the flame particles is found to increase with time for all conditions considered. This is because, eventually all flame surfaces and their resident flame particles approach annihilation by reactant island formation at the end of stretching and folding processes induced by turbulence. Statistics of principal curvature evolving in time, obtained using FPT, suggest that these islands are ellipsoidal on average enclosing fresh reactants. Further examinations show that the increase in Sd is caused by the increased negative curvature of the flame surface and eventual homogenization of temperature gradients as these reactant islands shrink due to flame propagation and turbulent mixing. Finally, the evolution of the normalized, averaged, displacement flame speed vs. stretch Karlovitz number are found to collapse on a narrow band, suggesting that a unified description of flame speed dependence on stretch rate may be possible in the Lagrangian description.

  5. A flame particle tracking analysis of turbulence–chemistry interaction in hydrogen–air premixed flames

    KAUST Repository

    Uranakara, Harshavardhana A.

    2015-11-21

    Interactions of turbulence, molecular transport, and energy transport, coupled with chemistry play a crucial role in the evolution of flame surface geometry, propagation, annihilation, and local extinction/re-ignition characteristics of intensely turbulent premixed flames. This study seeks to understand how these interactions affect flame surface annihilation of lean hydrogen–air premixed turbulent flames. Direct numerical simulations (DNSs) are conducted at different parametric conditions with a detailed reaction mechanism and transport properties for hydrogen–air flames. Flame particle tracking (FPT) technique is used to follow specific flame surface segments. An analytical expression for the local displacement flame speed (Sd) of a temperature isosurface is considered, and the contributions of transport, chemistry, and kinematics on the displacement flame speed at different turbulence-flame interaction conditions are identified. In general, the displacement flame speed for the flame particles is found to increase with time for all conditions considered. This is because, eventually all flame surfaces and their resident flame particles approach annihilation by reactant island formation at the end of stretching and folding processes induced by turbulence. Statistics of principal curvature evolving in time, obtained using FPT, suggest that these islands are ellipsoidal on average enclosing fresh reactants. Further examinations show that the increase in Sd is caused by the increased negative curvature of the flame surface and eventual homogenization of temperature gradients as these reactant islands shrink due to flame propagation and turbulent mixing. Finally, the evolution of the normalized, averaged, displacement flame speed vs. stretch Karlovitz number are found to collapse on a narrow band, suggesting that a unified description of flame speed dependence on stretch rate may be possible in the Lagrangian description.

  6. Improved electrolyte for zinc-bromine flow batteries

    Science.gov (United States)

    Wu, M. C.; Zhao, T. S.; Wei, L.; Jiang, H. R.; Zhang, R. H.

    2018-04-01

    Conventional zinc bromide electrolytes offer low ionic conductivity and often trigger severe zinc dendrite growth in zinc-bromine flow batteries. Here we report an improved electrolyte modified with methanesulfonic acid, which not only improves the electrolyte conductivity but also ameliorates zinc dendrite. Experimental results also reveal that the kinetics and reversibility of Zn2+/Zn and Br2/Br- are improved in this modified electrolyte. Moreover, the battery's internal resistance is significantly reduced from 4.9 to 2.0 Ω cm2 after adding 1 M methanesulfonic acid, thus leading to an improved energy efficiency from 64% to 75% at a current density of 40 mA cm-2. More impressively, the battery is capable of delivering an energy efficiency of about 78% at a current density of as high as 80 mA cm-2 when the electrode is replaced by a thermally treated one. Additionally, zinc dendrite growth is found to be effectively suppressed in methanesulfonic acid supported media, which, as a result, enables the battery to be operated for 50 cycles without degradation, whereas the one without methanesulfonic acid suffers from significant decay after only 40 cycles, primarily due to severe zinc dendrite growth. These superior results indicate methanesulfonic acid is a promising supporting electrolyte for zinc-bromine flow batteries.

  7. Comparative environmental analysis of waste brominated plastic thermal treatments

    International Nuclear Information System (INIS)

    Bientinesi, M.; Petarca, L.

    2009-01-01

    The aim of this research activity is to investigate the environmental impact of different thermal treatments of waste electric and electronic equipment (WEEE), applying a life cycle assessment methodology. Two scenarios were assessed, which both allow the recovery of bromine: (A) the co-combustion of WEEE and green waste in a municipal solid waste combustion plant, and (B) the staged-gasification of WEEE and combustion of produced syngas in gas turbines. Mass and energy balances on the two scenarios were set and the analysis of the life cycle inventory and the life cycle impact assessment were conducted. Two impact assessment methods (Ecoindicator 99 and Impact 2002+) were slightly modified and then used with both scenarios. The results showed that scenario B (staged-gasification) had a potentially smaller environmental impact than scenario A (co-combustion). In particular, the thermal treatment of staged-gasification was more energy efficient than co-combustion, and therefore scenario B performed better than scenario A, mainly in the impact categories of 'fossil fuels' and 'climate change'. Moreover, the results showed that scenario B allows a higher recovery of bromine than scenario A; however, Br recovery leads to environmental benefits for both the scenarios. Finally the study demonstrates that WEEE thermal treatment for energy and matter recovery is an eco-efficient way to dispose of this kind of waste

  8. Theoretical analysis of the conical premixed flame response to upstream velocity disturbances considering flame speed development effects

    OpenAIRE

    Ghazaleh Esmaeelzade; Mohammad Reza Khani; Rouzbeh Riazi; Mohammad Hossein Sabour

    2017-01-01

    The effect of upstream velocity perturbations on the response of a premixed flame was investigated in terms of the flame transfer function dependency on excitation frequency. In this study, the assumption of constant flame speed was extended and the effect of flame speed development was considered; i.e., the flame speed would grow with the time after ignition or with the distance from a flame-holder. In the present study, the kinematics of a conical flame was investigated by linearization of ...

  9. Bromine species fluxes from Lake Constance’s catchment, and a preliminary lake mass balance

    Science.gov (United States)

    Gilfedder, B. S.; Petri, M.; Wessels, M.; Biester, H.

    2011-06-01

    Bromine was historically termed a cyclic salt in terrestrial freshwater environments due to its perceived conservative cycling between the oceans and the continents. This basic assumption has been challenged recently, with evidence that bromine is involved in dynamic chemical cycles in soils and freshwaters. We present here a study on dissolved bromine species (bromide, organically bound bromine, DOBr) concentrations and fluxes as well as sediment trap bromine levels and fluxes in Lake Constance, a large lake in southern Germany. Water samples were obtained from all major and some minor inflows and outflows over one year, where-after dissolved bromine species were measured by a combination of ICP-MS and ion chromatography coupled to an ICP-MS (IC-ICP-MS). Sediment traps were deployed at two locations for two years with Br, Ti and Zr levels being measured by μ-XRF. 190 t yr -1 of total dissolved bromine (TDBr) was delivered to the lake via 14 rivers and precipitation, with the rivers Alpenrhein (84 t TDBr yr -1) and the Schussen (50 t TDBr yr -1) providing the largest sources. The estimated particulate bromine flux contributed an extra 24-26 t Br yr -1. In comparison, only 40 t TDBr yr -1 was deposited to the lake's catchment by precipitation, and thus ˜80% of the riverine TDBr flux came from soils and rocks. Bromide was the dominant species accounting for, on average, 78% of TDBr concentrations and 93% of TDBr flux to the lake. Despite some high concentrations in the smaller lowland rivers, DOBr was only a minor component of the total riverine bromine flux (˜12 t yr -1, 7%), most of which came from the rivers Schussen, Bregenzer Ach and Argen. In contrast, most of the bromine in the sediment traps was bound to organic matter, and showed a clear seasonal pattern in concentrations, with a maximum in winter and minimum in summer. The summer minimum is thought to be due to dilution of a high Br autochthonous component by low bromine mineral and organic material from

  10. Kinetic solvent isotope effects in the additions of bromine and 4-chlorobenzenesulfenyl chloride to alkenes and alkynes

    International Nuclear Information System (INIS)

    Modro, A.; Schmid, G.H.; Yates, K.

    1979-01-01

    The rates of bromination of selected alkenes and alkynes in methanol/methanol-d, acetic acid/acetic acid-d, and formic acid/formic acid-d have a nearly constant value of k/sub H//k/sub D/ = 1.23 +- 0.02. This kinetic solvent isotope effect is attributed to specific electrophilic solvation of the incipient bromide anion by hydrogen bonding in the rate-determining transition state. The rates of bromination were measured in two solvents having the same values of the solvent parameter Y but different nucleophilicities in order to assess the importance of nucleophilic solvation. Significant nucleophilic solvent assistance is found for only alkylacetylenes. The kinetic solvent isotope effects of the addition of 4-chlorobenzenesulfenyl chloride to selected alkenes and alkynes in acetic acid/acetic acid-d vary from 1.00 to 1.28. These data are consistent with two mechanisms: one involves a tetravalent sulfur intermediate while the second is the sulfur analogue of the S/sub N/2 mechanism

  11. Multicomponent Comparison of Optical and Mass Spectrometric Diagnostics in Low-Pressure Flames

    Science.gov (United States)

    1992-04-01

    flame chemistry relevant to gaseous flames of burning propellants. This instrument incorporates several spectral techniques in one apparatus so that...Rev. 2-89) Precribed by ANSI Std 31-11 298.102 ThiTENTIONALLY LEFr BLANK TABLE OF CONTENTS LIST OF FIGURES...known. Propellant selection and optimization are dependent upon burning characteristics and the products formed. Much modeling effort has been

  12. Pulse radiolysis studies of the reactions of bromine atoms and dimethyl sulfoxide bromine atom complexes with alcohols

    Science.gov (United States)

    Sumiyoshi, Takashi; Fujiyoshi, Ryoko; Katagiri, Miho; Sawamura, Sadashi

    2007-05-01

    Dimethylsulfoxide (DMSO)-Br complexes were generated by pulse radiolysis of DMSO/bromomethane mixtures and the formation mechanism and spectral characteristics of the formed complexes were investigated in detail. The rate constant for the reaction of bromine atoms with DMSO and the extinction coefficient of the complex were obtained to be 4.6×10 9 M -1 s -1 and 6300 M -1 cm -1 at the absorption maximum of 430 nm. Rate constants for the reaction of bromine atoms with a series of alcohols were determined in CBrCl 3 solutions applying a competitive kinetic method using the DMSO-Br complex as the reference system. The obtained rate constants were ˜10 8 M -1 s -1, one or two orders larger than those reported for highly polar solvents. Rate constants of DMSO-Br complexes with alcohols were determined to be ˜ 10 7 M -1 s -1. A comparison of the reactivities of Br atoms and DMSO-Br complexes with those of chlorine atoms and chlorine atom complexes which are ascribed to hydrogen abstracting reactants strongly indicates that hydrogen abstraction from alcohols is not the rate determining step in the case of Br atoms and DMSO-Br complexes.

  13. Toxicity and physiological effects of brominated flame retardant PBDE-47 on two life stages of grass shrimp, Palaemonetes pugio.

    Science.gov (United States)

    Key, Peter B; Chung, Katy W; Hoguet, Jennifer; Shaddrix, Brian; Fulton, Michael H

    2008-07-25

    This study examined the effects of a polybrominated diphenyl ether (PBDE) compound, PBDE-47, on adult and larval stages of the estuarine grass shrimp (Palaemonetes pugio). The 96-h LC50 test resulted in an estimate of 23.60 microg/L (95% confidence interval=14.51-38.37 microg/L) for larval shrimp. Adult shrimp had a higher 96-h LC50 of 78.07 microg/L (95% CI=65.1-93.63 microg/L). Four physiological biomarkers glutathione (GSH), lipid peroxidation (LPx), cholesterol (CHL) and acetylcholinesterase (AChE) were then assessed to study the sublethal effects of PBDE-47 exposure. GSH, LPx and AChE levels in both adults and larvae were not affected by PBDE-47 at concentrations up to 50 microg/L for 96 h. CHL levels were elevated in adults and larvae at the lowest exposure concentrations tested, but significant differences were found only in adult exposures. Effects associated with PBDE-47 aqueous exposures were observed at levels well above those reported in the environment.

  14. Exposure to brominated flame retardant PBDE-99 affects cytoskeletal protein expression in the neonatal mouse cerebral cortex

    DEFF Research Database (Denmark)

    Alm, Henrik; Kultima, Kim; Scholz, Birger

    2008-01-01

    , and the cytotoxic and apoptotic effects of PBDE-99 in primary cultures of fetal rat cortical cells. We used two-dimensional difference gel electrophoresis (2D-DIGE) to analyze protein samples isolated from the cortex of NMRI mice 24h after exposure to a single oral dose of 12 mg/kg PBDE-99 on post-natal day 10....... Protein resolution was enhanced by sample pre-fractionation. In the cell model, we determined cell viability using the trypan blue exclusion assay, and apoptosis using immunocytochemical detection of cleaved caspase-3. We determined the identity of 111 differentially expressed proteins, 32 (29%) of which...... are known to be cytoskeleton-related. Similar to previous findings in the striatum, we found elevated levels of the neuron growth-associated protein Gap43 in the cortex. In cultured cortical cells, a high concentration of PBDE-99 (30 microM) induced cell death without any apparent increase in caspase-3...

  15. Impact of flame-wall interaction on premixed flame dynamics and transfer function characteristics

    KAUST Repository

    Kedia, K.S.; Altay, H.M.; Ghoniem, A.F.

    2011-01-01

    In this paper, we numerically investigate the response of a perforated-plate stabilized laminar methane-air premixed flame to imposed inlet velocity perturbations. A flame model using detailed chemical kinetics mechanism is applied and heat exchange

  16. Extinction of corrugated hydrogen/air flames

    International Nuclear Information System (INIS)

    Mizomoto, M.; Asaka, Y.; Ikai, S.; Law, C.K.

    1982-01-01

    Recent studies on flammability limits reveal the importance of flow nonuniformity, flame curvature, and molecular and thermal diffusivities in determining the extinguishability and the associated limits of premixed fuel/air flames. In particular, it is found that conditions which favor extinction of a lean flame may cause intensification of a rich flame. In the present study the authors have experimentally determined the extinction characteristics and limits of highly curved hydrogen/air flames as represented by the opening of bunsen flame tips. Results show that the tip opens at a constant fuel equivalence ratio of phi = 1.15, regardless of the velocity and uniformity of the upstream flow. This critical mixture concentration, while being rich, is still on the lean side of that corresponding to the maximum burning velocity (phi = 1.8), implying that for highly diffusive systems, the relevant reference concentration is that for maximum burning velocity instead of stoichiometry

  17. Microfluidic Flame Barrier

    Science.gov (United States)

    Mungas, Gregory S. (Inventor); Fisher, David J. (Inventor); Mungas, Christopher (Inventor)

    2013-01-01

    Propellants flow through specialized mechanical hardware that is designed for effective and safe ignition and sustained combustion of the propellants. By integrating a micro-fluidic porous media element between a propellant feed source and the combustion chamber, an effective and reliable propellant injector head may be implemented that is capable of withstanding transient combustion and detonation waves that commonly occur during an ignition event. The micro-fluidic porous media element is of specified porosity or porosity gradient selected to be appropriate for a given propellant. Additionally the propellant injector head design integrates a spark ignition mechanism that withstands extremely hot running conditions without noticeable spark mechanism degradation.

  18. Flame Motion In Gas Turbine Burner From Averages Of Single-Pulse Flame Fronts

    Energy Technology Data Exchange (ETDEWEB)

    Tylli, N.; Hubschmid, W.; Inauen, A.; Bombach, R.; Schenker, S.; Guethe, F. [Alstom (Switzerland); Haffner, K. [Alstom (Switzerland)

    2005-03-01

    Thermo acoustic instabilities of a gas turbine burner were investigated by flame front localization from measured OH laser-induced fluorescence single pulse signals. The average position of the flame was obtained from the superposition of the single pulse flame fronts at constant phase of the dominant acoustic oscillation. One observes that the flame position varies periodically with the phase angle of the dominant acoustic oscillation. (author)

  19. Combustion instabilities in sudden expansion oxy-fuel flames

    Energy Technology Data Exchange (ETDEWEB)

    Ditaranto, Mario; Hals, Joergen [Department of Energy Processes, SINTEF Energy Research, 7465 Trondheim (Norway)

    2006-08-15

    An experimental study on combustion instability is presented with focus on oxy-fuel type combustion. Oxidants composed of CO{sub 2}/O{sub 2} and methane are the reactants flowing through a premixer-combustor system. The reaction starts downstream a symmetric sudden expansion and is at the origin of different instability patterns depending on oxygen concentration and Reynolds number. The analysis has been conducted through measurement of pressure, CH* chemiluminescence, and velocity. As far as stability is concerned, oxy-fuel combustion with oxygen concentration similar to that found in air combustion cannot be sustained, but requires at least 30% oxygen to perform in a comparable manner. Under these conditions and for the sudden expansion configuration used in this study, the instability is at low frequency and low amplitude, controlled by the flame length inside the combustion chamber. Above a threshold concentration in oxygen dependent on equivalence ratio, the flame becomes organized and concentrated in the near field. Strong thermoacoustic instability is then triggered at characteristic acoustic modes of the system. Different modes can be triggered depending on the ratio of flame speed to inlet velocity, but for all types of instability encountered, the heat release and pressure fluctuations are linked by a variation in mass-flow rate. An acoustic model of the system coupled with a time-lag-based flame model made it possible to elucidate the acoustic mode selection in the system as a function of laminar flame speed and Reynolds number. The overall work brings elements of reflection concerning the potential risk of strong pressure oscillations in future gas turbine combustors for oxy-fuel gas cycles. (author)

  20. Potential human exposure to halogenated flame-retardants in elevated surface dust and floor dust in an academic environment

    International Nuclear Information System (INIS)

    Allgood, Jaime M.; Jimah, Tamara; McClaskey, Carolyn M.; La Guardia, Mark J.; Hammel, Stephanie C.; Zeineddine, Maryam M.; Tang, Ian W.; Runnerstrom, Miryha G.; Ogunseitan, Oladele A.

    2017-01-01

    Most households and workplaces all over the world possess furnishings and electronics, all of which contain potentially toxic flame retardant chemicals to prevent fire hazards. Indoor dust is a recognized repository of these types of chemicals including polybrominated diphenyl ethers (PBDEs) and non-polybrominated diphenyl ethers (non-PBDEs). However, no previous U.S. studies have differentiated concentrations from elevated surface dust (ESD) and floor dust (FD) within and across microenvironments. We address this information gap by measuring twenty-two flame-retardant chemicals in dust on elevated surfaces (ESD; n=10) and floors (FD; n=10) from rooms on a California campus that contain various concentrations of electronic products. We hypothesized a difference in chemical concentrations in ESD and FD. Secondarily, we examined whether or not this difference persisted: (a) across the studied microenvironments and (b) in rooms with various concentrations of electronics. A Wilcoxon signed-rank test demonstrated that the ESD was statistically significantly higher than FD for BDE-47 (p=0.01), BDE-99 (p=0.01), BDE-100 (p=0.01), BDE-153 (p=0.02), BDE-154 (p=0.02), and 3 non-PBDEs including EH-TBB (p=0.02), BEH-TEBP (p=0.05), and TDCIPP (p=0.03). These results suggest different levels and kinds of exposures to flame-retardant chemicals for individuals spending time in the sampled locations depending on the position of accumulated dust. Therefore, further research is needed to estimate human exposure to flame retardant chemicals based on how much time and where in the room individuals spend their time. Such sub-location estimates will likely differ from assessments that assume continuous unidimensional exposure, with implications for improved understanding of potential health impacts of flame retardant chemicals. - Highlights: • Brominated flame retardants used in electronic products accumulate in room dust • Various chemical moieties of flame retardants leach

  1. Potential human exposure to halogenated flame-retardants in elevated surface dust and floor dust in an academic environment

    Energy Technology Data Exchange (ETDEWEB)

    Allgood, Jaime M.; Jimah, Tamara [Department of Population Health & Disease Prevention, Program in Public Health, University of California, Irvine, CA 92697-3957 (United States); McClaskey, Carolyn M. [Department of Cognitive Sciences, School of Social Sciences, University of California, Irvine, CA 92697-5100 (United States); La Guardia, Mark J. [Department of Aquatic Health Sciences, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062 (United States); Hammel, Stephanie C.; Zeineddine, Maryam M.; Tang, Ian W.; Runnerstrom, Miryha G. [Department of Population Health & Disease Prevention, Program in Public Health, University of California, Irvine, CA 92697-3957 (United States); Ogunseitan, Oladele A., E-mail: Oladele.Ogunseitan@uci.edu [Department of Population Health & Disease Prevention, Program in Public Health, University of California, Irvine, CA 92697-3957 (United States)

    2017-02-15

    Most households and workplaces all over the world possess furnishings and electronics, all of which contain potentially toxic flame retardant chemicals to prevent fire hazards. Indoor dust is a recognized repository of these types of chemicals including polybrominated diphenyl ethers (PBDEs) and non-polybrominated diphenyl ethers (non-PBDEs). However, no previous U.S. studies have differentiated concentrations from elevated surface dust (ESD) and floor dust (FD) within and across microenvironments. We address this information gap by measuring twenty-two flame-retardant chemicals in dust on elevated surfaces (ESD; n=10) and floors (FD; n=10) from rooms on a California campus that contain various concentrations of electronic products. We hypothesized a difference in chemical concentrations in ESD and FD. Secondarily, we examined whether or not this difference persisted: (a) across the studied microenvironments and (b) in rooms with various concentrations of electronics. A Wilcoxon signed-rank test demonstrated that the ESD was statistically significantly higher than FD for BDE-47 (p=0.01), BDE-99 (p=0.01), BDE-100 (p=0.01), BDE-153 (p=0.02), BDE-154 (p=0.02), and 3 non-PBDEs including EH-TBB (p=0.02), BEH-TEBP (p=0.05), and TDCIPP (p=0.03). These results suggest different levels and kinds of exposures to flame-retardant chemicals for individuals spending time in the sampled locations depending on the position of accumulated dust. Therefore, further research is needed to estimate human exposure to flame retardant chemicals based on how much time and where in the room individuals spend their time. Such sub-location estimates will likely differ from assessments that assume continuous unidimensional exposure, with implications for improved understanding of potential health impacts of flame retardant chemicals. - Highlights: • Brominated flame retardants used in electronic products accumulate in room dust • Various chemical moieties of flame retardants leach

  2. Characteristics of Oscillating Flames in a Coaxial Confined Jet

    Directory of Open Access Journals (Sweden)

    Min Suk Cha

    2010-12-01

    Full Text Available Flame characteristics when a non-premixed n-butane jet is ejected into a coaxial cylindrical tube are investigated experimentally. Flame stability depends mainly on the characteristics of flame propagation as well as air entrainment which depend on the jet momentum and on the distance between the nozzle exit and the base of a confined tube. As flow rate increases, the flame lifts off from a nozzle attached diffusion flame and a stationary lifted flame can be stabilized. The liftoff height increases nearly linearly with the average velocity at the nozzle exit. The lifted flame has a tribrachial flame structure, which consists of a rich premixed flame, a lean premixed flame, and a diffusion flame, all extending from a single location. As flow rate further increases, periodically oscillating flames are observed inside the confined tube. Once flame oscillation occurs, the flame undergoes relatively stable oscillation such that it has nearly constant oscillation amplitude and frequency. The criteria of flame oscillation are mapped as functions of nozzle diameter, the distance between nozzle and tube, and jet velocity. This type of flame oscillation can be characterized by Strouhal number in terms of flame oscillation amplitude, frequency, and jet velocity. Buoyancy driven flame oscillation which is one of the viable mechanism for flame oscillation is modeled and the results agrees qualitatively with experimental results, suggesting that the oscillation is due to periodic blowoff and flashback under the influence of buoyancy.

  3. Pole solutions for flame front propagation

    CERN Document Server

    Kupervasser, Oleg

    2015-01-01

    This book deals with solving mathematically the unsteady flame propagation equations. New original mathematical methods for solving complex non-linear equations and investigating their properties are presented. Pole solutions for flame front propagation are developed. Premixed flames and filtration combustion have remarkable properties: the complex nonlinear integro-differential equations for these problems have exact analytical solutions described by the motion of poles in a complex plane. Instead of complex equations, a finite set of ordinary differential equations is applied. These solutions help to investigate analytically and numerically properties of the flame front propagation equations.

  4. Gravitational Effects on Cellular Flame Structure

    Science.gov (United States)

    Dunsky, C. M.; Fernandez-Pello, A. C.

    1991-01-01

    An experimental investigation has been conducted of the effect of gravity on the structure of downwardly propagating, cellular premixed propane-oxygen-nitrogen flames anchored on a water-cooled porous-plug burner. The flame is subjected to microgravity conditions in the NASA Lewis 2.2-second drop tower, and flame characteristics are recorded on high-speed film. These are compared to flames at normal gravity conditions with the same equivalence ratio, dilution index, mixture flow rate, and ambient pressure. The results show that the cellular instability band, which is located in the rich mixture region, changes little under the absence of gravity. Lifted normal-gravity flames near the cellular/lifted limits, however, are observed to become cellular when gravity is reduced. Observations of a transient cell growth period following ignition point to heat loss as being an important mechanism in the overall flame stability, dominating the stabilizing effect of buoyancy for these downwardly-propagating burner-anchored flames. The pulsations that are observed in the plume and diffusion flame generated downstream of the premixed flame in the fuel rich cases disappear in microgravity, verifying that these fluctuations are gravity related.

  5. Analytical and environmental aspects of the flame retardant tetrabromobisphenol-A and its derivatives.

    Science.gov (United States)

    Covaci, Adrian; Voorspoels, Stefan; Abdallah, Mohamed Abou-Elwafa; Geens, Tinne; Harrad, Stuart; Law, Robin J

    2009-01-16

    The present article reviews the available literature on the analytical and environmental aspects of tetrabromobisphenol-A (TBBP-A), a currently intensively used brominated flame retardant (BFR). Analytical methods, including sample preparation, chromatographic separation, detection techniques, and quality control are discussed. An important recent development in the analysis of TBBP-A is the growing tendency for liquid chromatographic techniques. At the detection stage, mass-spectrometry is a well-established and reliable technology in the identification and quantification of TBBP-A. Although interlaboratory exercises for BFRs have grown in popularity in the last 10 years, only a few participating laboratories report concentrations for TBBP-A. Environmental levels of TBBP-A in abiotic and biotic matrices are low, probably due to the major use of TBBP-A as reactive FR. As a consequence, the expected human exposure is low. This is in agreement with the EU risk assessment that concluded that there is no risk for humans concerning TBBP-A exposure. Much less analytical and environmental information exists for the various groups of TBBP-A derivatives which are largely used as additive flame retardants.

  6. Bromine-doped DWNTs: A Molecular Faraday Cage

    Science.gov (United States)

    Chen, Gugang; Margine, Roxana; Gupta, Rajeev; Crespi, Vincent; Eklund, Peter; Sumanasekera, Gamini; Bandow, Shunji; Iijima, S.

    2003-03-01

    Raman scattering is used to probe the charge transfer distribution in Bromine-doped double-walled carbon nanotubes (DWNT). Using 1064 nm and 514.5 nm laser excitation we are able to study the charge-transfer sensitive phonons in the inner ( (5,5)) and outer ( (10,10)) tubes of the double-walled pair. The experimental results are compared to our tight binding band structure calculations that include a self-consistent electrostatic term sensitive to the average net charge density on each tube. Upon doping, the nanotube tangential and radial Raman bands from the outer (primary) tubes were observed to shift dramatically to higher frequencies, consistent with a C-C bond contraction driven by the acceptor-doping. The peak intensities of these bands significantly decreased with increasing doping exposure, and they eventually vanished, consistent with a deep depression in the Fermi energy that extinguishes the resonant Raman effect. Interestingly, at the same time, we observed little or no change for the tangential and radial Raman features identified with the inner (secondary) tubes during the bromine doping. Our electronic structure calculations show that the charge distribution between the outer and inner tubes depends on doping level and also, to some extent, on specific tube chirality combinations. In general, in agreement with experiment, the calculations find a very small net charge on the inner tube, consistent with a "Molecular Faraday Effect", e.g., a DWNT of (10, 10)/ (5, 5) configuration that exhibits 0.5 holes/Å total charge transfer, has only 0.04 holes/Å on the inner (secondary) tube.

  7. A Numerical Study on Premixed Bluff Body Flame of Different Bluff Apex Angle

    Directory of Open Access Journals (Sweden)

    Gelan Yang

    2013-01-01

    Full Text Available In order to investigate effects of apex angle (α on chemically reacting turbulent flow and thermal fields in a channel with a bluff body V-gutter flame holder, a numerical study has been carried out in this paper. With a basic geometry used in a previous experimental study, the apex angle was varied from 45° to 150°. Eddy dissipation concept (EDC combustion model was used for air and propane premixed flame. LES-Smagorinsky model was selected for turbulence. The gird-dependent learning and numerical model verification were done. Both nonreactive and reactive conditions were analyzed and compared. The results show that as α increases, recirculation zone becomes bigger, and Strouhal number increases a little in nonreactive cases while decreases a little in reactive cases, and the increase of α makes the flame shape wider, which will increase the chamber volume heat release ratio and enhance the flame stability.

  8. Theoretical analysis of the conical premixed flame response to upstream velocity disturbances considering flame speed development effects

    Directory of Open Access Journals (Sweden)

    Ghazaleh Esmaeelzade

    2017-03-01

    Full Text Available The effect of upstream velocity perturbations on the response of a premixed flame was investigated in terms of the flame transfer function dependency on excitation frequency. In this study, the assumption of constant flame speed was extended and the effect of flame speed development was considered; i.e., the flame speed would grow with the time after ignition or with the distance from a flame-holder. In the present study, the kinematics of a conical flame was investigated by linearization of the front tracking equation of flame to uniform and convected fluctuations of the flow velocity and the response was compared with that of a V-shaped flame and the experimental data in the previous studies. The results show that the effect of flame speed development could influence a decreasing gain and increase the phase of the flame response to the uniform velocity oscillations in low and moderate frequencies. Comparing the variations in the gain of flame response upon normalized frequency, show that a conical flame has lower values than the V-flame. In other words, these flames might be less susceptible to combustion instabilities than the V-flames. Furthermore, the variations in phase of the V-flames responses, which show a quasi-linear behavior with normalized frequency, have higher values than the saturated behavior in phase of the conical flame responses. Also, considering that the flame speed development induces an increase in the gain and phase of the conical flame response to the convected velocity oscillations in certain frequencies; because the developed flame front has longer length in comparison to the flame front in constant flame speed model. Therefore, the flame length may be longer than convective wavelength and the heat release would be generated in different points of the flame; consequently the flow oscillations might exert a stronger impact on the unsteady heat release fluctuations.

  9. A review of chamber experiments for determining specific emission rates and investigating migration pathways of flame retardants

    Science.gov (United States)

    Rauert, Cassandra; Lazarov, Borislav; Harrad, Stuart; Covaci, Adrian; Stranger, Marianne

    2014-01-01

    The widespread use of flame retardants (FRs) in indoor products has led to their ubiquitous distribution within indoor microenvironments with many studies reporting concentrations in indoor air and dust. Little information is available however on emission of these compounds to air, particularly the measurement of specific emission rates (SERs), or the migration pathways leading to dust contamination. Such knowledge gaps hamper efforts to develop understanding of human exposure. This review summarizes published data on SERs of the following FRs released from treated products: polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), tetrabromobisphenol-A (TBBPA), novel brominated flame retardants (NBFRs) and organophosphate flame retardants (PFRs), including a brief discussion of the methods used to derive these SERs. Also reviewed are published studies that utilize emission chambers for investigations/measurements of mass transfer of FRs to dust, discussing the chamber configurations and methods used for these experiments. A brief review of studies investigating correlations between concentrations detected in indoor air/dust and possible sources in the microenvironment is included along with efforts to model contamination of indoor environments. Critical analysis of the literature reveals that the major limitations with utilizing chambers to derive SERs for FRs arise due to the physicochemical properties of FRs. In particular, increased partitioning to chamber surfaces, airborne particles and dust, causes loss through “sink” effects and results in long times to reach steady state conditions inside the chamber. The limitations of chamber experiments are discussed as well as their potential for filling gaps in knowledge in this area.

  10. Real Time Flame Monitoring of Gasifier and Injectors

    Energy Technology Data Exchange (ETDEWEB)

    Zelepouga, Serguei; Saveliev, Alexei

    2011-12-31

    This project is a multistage effort with the final goal to develop a practical and reliable nonintrusive gasifier injector monitor to assess burner wear and need for replacement. The project team included the National Energy Technology Laboratory (NETL), Gas Technology Institute (GTI), North Carolina State University, and ConocoPhillips. This report presents the results of the sensor development and testing initially at GTI combustion laboratory with natural gas flames, then at the Canada Energy Technology Center (CANMET), Canada in the atmospheric coal combustor as well as in the pilot scale pressurized entrained flow gasifier, and finally the sensor capabilities were demonstrated at the Pratt and Whitney Rocketdyne (PWR) Gasifier and the Wabash River Repowering plant located in West Terre Haute, IN. The initial tests demonstrated that GTI gasifier sensor technology was capable of detecting shape and rich/lean properties of natural gas air/oxygen enriched air flames. The following testing at the Vertical Combustor Research Facility (VCRF) was a logical transition step from the atmospheric natural gas flames to pressurized coal gasification environment. The results of testing with atmospheric coal flames showed that light emitted by excited OH* and CH* radicals in coal/air flames can be detected and quantified. The maximum emission intensities of OH*, CH*, and black body (char combustion) occur at different axial positions along the flame length. Therefore, the excitation rates of CH* and OH* are distinct at different stages of coal combustion and can be utilized to identify and characterize processes which occur during coal combustion such as devolatilization, char heating and burning. To accomplish the goals set for Tasks 4 and 5, GTI utilized the CANMET Pressurized Entrained Flow Gasifier (PEFG). The testing parameters of the PEFG were selected to simulate optimum gasifier operation as well as gasifier conditions normally resulting from improper operation or

  11. Experimental studies of flame stability limits of biogas flame

    International Nuclear Information System (INIS)

    Dai Wanneng; Qin Chaokui; Chen Zhiguang; Tong Chao; Liu Pengjun

    2012-01-01

    Highlights: ► Premixed biogas flame stability for RTBs was studied on different conditions. ► An unusual “float off” phenomenon was observed. ► Decrease of port diameter or gas temperature or methane content motivates lifting. ► Increase of methane content or gas temperature or port diameter motivates yellow tipping. ► Lifting curves become straight lines when semi-logarithmic graph paper is applied. - Abstract: Flame stability of premixed biogas flame for Reference Test Burner (RTB) was investigated. In this study, six kinds of test gases were used to simulate biogas in which CO 2 volume fraction varied from 30% to 45%. A series of experiments were conducted on two RTBs with different port diameters and at different outlet unburned mixture temperatures. It was found that the lifting and yellow tipping limits show similar trends regardless of the biogas components, port diameters and mixture temperatures. A “float off” phenomenon could be observed at low gas flow rate and low primary air ratio. Low mixture temperature, small ports and high CO 2 concentration in biogas can lead to the unstable condition of “float off”. The lifting limits are enhanced with an increase of port diameter or mixture temperature and with a decrease of CO 2 concentration. The yellow tipping limits are extended with an increase of CO 2 concentration and with a decrease of mixture temperature or port diameter. In addition, the lifting limit curve becomes a straight line when semi-logarithmic graph paper is applied. The intercept increases with a decrease of the CO 2 concentration in biogas and with an increase of port diameter or gas temperature.

  12. Preparation of radioactive labelled compounds Pt.1. 82Br labelled organic bromine compounds

    International Nuclear Information System (INIS)

    Otto, R.

    1988-05-01

    A simple method allowing the preparation of 82 Br labelled organic bromine compounds from olefins with chemical and radiochemical yields between 75 and 95% and the specific activities required, is described [fr

  13. Theoretical study of the reaction kinetics of atomic bromine with tetrahydropyran

    KAUST Repository

    Giri, Binod; Lo, John M H; Roscoe, John M.; Alquaity, Awad; Farooq, Aamir

    2015-01-01

    A detailed theoretical analysis of the reaction of atomic bromine with tetrahydropyran (THP, C5H10O) was performed using several ab initio methods and statistical rate theory calculations. Initial geometries of all species involved in the potential

  14. Bromine determination by neutron activation analysis and its distribution in the atmosphere

    International Nuclear Information System (INIS)

    Iturbe Garcia, J.L.; Lopez Munoz, B.E.

    2002-01-01

    Bromine, one of the main participants in ozone layer destruction, is 10 to 100 times more effective than chlorine. There are two principal sources of methyl bromide emissions: the oceans and some pesticides that are used in farming. Bromine was detected in 'premium' and 'magna sin' gasolines (2.86±0.96 and 1.54±0.38 ppm, respectively) as well as in condensed water found in exhaust pipes of vehicles. In addition, samples of rainwater were also analyzed to determine atmospheric bromine concentration. In water samples Br concentrations ranging from 2.09 to 0.06 ppm were found. The techniques utilised were neutron activation analysis and high voltage electrophoresis, the latter to determine the chemical form of bromine in condensed water samples. Finally, suspended particles from rainwater were also analysed by scanning electron microscopy (SEM). (author)

  15. Dynamic dielectric properties and the γ transition of bromine doped polyacrylonitrile

    Directory of Open Access Journals (Sweden)

    2007-10-01

    Full Text Available Based on monitoring the γ process (the lowest temperature-relaxation in polyacrylonitrile (PAN by dynamic dielectric spectroscopy, new evidence for the formation of a charge transfer complex between bromine dopants and nitrile groups is presented. The experimental work is carried out on PAN and nitrile polymerized PAN with and without bromine doping and the effects of these factors on the γ process are measured. Nitrile polymerization results in diminishing of the γ process and in a 15% increase in its activation energy, whereas bromine doping produces splitting of the original γ process in PAN – coupled with a significant activation energy increase – and its complete disappearance in nitrile polymerized PAN. Both the splitting of the γ process and the higher activation energy reflect bromine-nitrile adduct formation..

  16. Bromine and iodine in Chinese medical herbs determined via epithermal neutron activation analysis

    International Nuclear Information System (INIS)

    Chien-Yi Chen; Yuan-Yaw Wei; Sheng-Pin ChangLai; Lung-Kwang Pan

    2003-01-01

    Nineteen natural herbs and two prescriptions prepared from mixed herbs were analyzed via epithermal neutron activation analysis (ENAA) to evaluate their bromine and iodine concentration. Traditional medical doctors prescribed the samples presented in this work to most Taiwanese children for strengthening their immune systems. Empirical results indicated a wide diversity of bromine in the samples. Yet, the iodine concentration was only around one to tenth or twentieth of the bromine. The maximum daily intake (MDI) for various medical herbs was also widely diversified from one to tenfold on the basis of various criteria. The minimum detectable concentration (MDC) of bromine and iodine found was 0.42±0.14 ppm and 0.067±0.016 ppm, respectively. Compared to that from conventional thermal neutron activation analysis (NAA) for a similar evaluation, the extremely low MDC obtained here was attributed to the large amount of thermal neutron absorption during sample irradiation. (author)

  17. Flame dynamics of a meso-scale heat recirculating combustor

    Energy Technology Data Exchange (ETDEWEB)

    Vijayan, V.; Gupta, A.K. [Department of Mechanical Engineering, University of Maryland, College Park, MD 20742 (United States)

    2010-12-15

    The dynamics of premixed propane-air flame in a meso-scale ceramic combustor has been examined here. The flame characteristics in the combustor were examined by measuring the acoustic emissions and preheat temperatures together with high-speed cinematography. For the small-scale combustor, the volume to surface area ratio is small and hence the walls have significant effect on the global flame structure, flame location and flame dynamics. In addition to the flame-wall thermal coupling there is a coupling between flame and acoustics in the case of confined flames. Flame-wall thermal interactions lead to low frequency flame fluctuations ({proportional_to}100 Hz) depending upon the thermal response of the wall. However, the flame-acoustic interactions can result in a wide range of flame fluctuations ranging from few hundred Hz to few kHz. Wall temperature distribution is one of the factors that control the amount of reactant preheating which in turn effects the location of flame stabilization. Acoustic emission signals and high-speed flame imaging confirmed that for the present case flame-acoustic interactions have more significant effect on flame dynamics. Based on the acoustic emissions, five different flame regimes have been identified; whistling/harmonic mode, rich instability mode, lean instability mode, silent mode and pulsating flame mode. (author)

  18. Molecular dynamics simulations and thermochemistry of reactive ion etching of silicon by chlorine, chlorine dimer, bromine, and bromine dimer cations

    Energy Technology Data Exchange (ETDEWEB)

    Valone, S.M.; Hanson, D.E.; Kress, J.D.

    1998-05-08

    Simulations of Cl plasma etch of Si surfaces with MD techniques agree reasonably well with the available experimental information on yields and surface morphologies. This information has been supplied to a Monte Carlo etch profile resulting in substantial agreement with comparable inputs provided through controlled experiments. To the extent that more recent measurements of etch rates are more reliable than older ones, preliminary MD simulations using bond-order corrections to the atomic interactions between neighboring Si atoms on the surface improves agreement with experiment through an increase in etch rate and improved agreement with XPS measurements of surface stoichiometry. Thermochemical and geometric analysis of small Si-Br molecules is consistent with the current notions of the effects of including brominated species in etchant gases.

  19. Fish energy budget under ocean warming and flame retardant exposure.

    Science.gov (United States)

    Anacleto, Patrícia; Figueiredo, Cátia; Baptista, Miguel; Maulvault, Ana Luísa; Camacho, Carolina; Pousão-Ferreira, Pedro; Valente, Luísa M P; Marques, António; Rosa, Rui

    2018-07-01

    Climate change and chemical contamination are global environmental threats of growing concern for the scientific community and regulatory authorities. Yet, the impacts and interactions of both stressors (particularly ocean warming and emerging chemical contaminants) on physiological responses of marine organisms remain unclear and still require further understanding. Within this context, the main goal of this study was to assess, for the first time, the effects of warming (+ 5 °C) and accumulation of a polybrominated diphenyl ether congener (BDE-209, brominated flame retardant) through dietary exposure on energy budget of the juvenile white seabream (Diplodus sargus). Specifically, growth (G), routine metabolism (R), excretion (faecal, F and nitrogenous losses, U) and food consumption (C) were calculated to obtain the energy budget. The results demonstrated that the energy proportion spent for G dominated the mode of the energy allocation of juvenile white seabream (56.0-67.8%), especially under the combined effect of warming plus BDE-209 exposure. Under all treatments, the energy channelled for R varied around 26% and a much smaller percentage was channelled for excretion (F: 4.3-16.0% and U: 2.3-3.3%). An opposite trend to G was observed to F, where the highest percentage (16.0 ± 0.9%) was found under control temperature and BDE-209 exposure via diet. In general, the parameters were significantly affected by increased temperature and flame retardant exposure, where higher levels occurred for: i) wet weight, relative growth rate, protein and ash contents under warming conditions, ii) only for O:N ratio under BDE-209 exposure via diet, and iii) for feed efficiency, ammonia excretion rate, routine metabolic rate and assimilation efficiency under the combination of both stressors. On the other hand, decreased viscerosomatic index was observed under warming and lower fat content was observed under the combined effect of both stressors. Overall, under future

  20. Tulip flames: changes in shape of premixed flames propagating in closed tubes

    Science.gov (United States)

    Dunn-Rankin, D.; Sawyer, R. F.

    The experimental results that are the subject of this communication provide high-speed schlieren images of the closed-tube flame shape that has come to be known as the tulip flame. The schlieren images, along with in-chamber pressure records, help demonstrate the effects of chamber length, equivalence ratio, and igniter geometry on formation of the tulip flame. The pressure/time records show distinct features which correlate with flame shape changes during the transition to tulip. The measurements indicate that the basic tulip flame formation is a robust phenomenon that depends on little except the overall geometry of the combustion vessel.

  1. Determination of arsenic and bromine in hot spring waters by neutron activation analysis

    International Nuclear Information System (INIS)

    Kikawada, Y.; Kawai, S.; Oi, T.

    2004-01-01

    Concentrations of arsenic and bromine dissolved in hot spring waters have been determined by neutron activation analysis using 0.5 cm 3 of sample waters without any chemical pretreatment. The samples prepared for neutron irradiation were simply pieces of filter papers which were infiltrated with samples. With the results of satisfactorily high accuracy and precision, this analytical method was found to be very convenient for the determinations of arsenic and bromine dissolved in water at ppm to sub-ppm levels. (author)

  2. Improvement of flame resistance of non-flame retardant cables by applying fire protection measures

    International Nuclear Information System (INIS)

    Takemura, Yujiro; Segoshi, Yoshinori; Jinno, Susumu; Mii, Kazuki

    2017-01-01

    The new regulatory requirements, which were put in force after the Fukushima Daiichi accident, impose the use of flame retardant cables on the plant components having safety functions for the purpose of fire protection. However, some Japanese nuclear power plants built in the early days use non-flame retardant cables that do not pass the demonstration test to check for the flame resistance. To cope with the new regulatory requirements, a fire protection measure for non-flame retardant cables was introduced to assure flame resistance of non-flame retardant cables equivalent to or higher than that of flame retardant cables. To illustrate the fire protection measure, both non-flame retardant cables and its cable tray are covered with fire protection sheet fabricated from incombustible material to form an assembly. Considering the demonstration test results, it can be concluded that flame resistance performance of non-flame retardant cables equivalent to or higher than that of flame retardant cables can be assured by forming the assembly even if an external fire outside the assembly and internal cable fire inside the assembly are assumed. This paper introduces the design of the assembly consisting of a bundle of cables and a cable tray and summarizes the results of demonstration tests. (author)

  3. Impact of flame-wall interaction on premixed flame dynamics and transfer function characteristics

    KAUST Repository

    Kedia, K.S.

    2011-01-01

    In this paper, we numerically investigate the response of a perforated-plate stabilized laminar methane-air premixed flame to imposed inlet velocity perturbations. A flame model using detailed chemical kinetics mechanism is applied and heat exchange between the burner plate and the gas mixture is incorporated. Linear transfer functions, for low mean inlet velocity oscillations, are analyzed for different equivalence ratio, mean inlet velocity, plate thermal conductivity and distance between adjacent holes. The oscillations of the heat exchange rate at the top of the burner surface plays a critical role in driving the growth of the perturbations over a wide range of conditions, including resonance. The flame response to the perturbations at its base takes the form of consumption speed oscillations in this region. Flame stand-off distance increases/decreases when the flame-wall interaction strengthens/weakens, impacting the overall dynamics of the heat release. The convective lag between the perturbations and the flame base response govern the phase of heat release rate oscillations. There is an additional convective lag between the perturbations at the flame base and the flame tip which has a weaker impact on the heat release rate oscillations. At higher frequencies, the flame-wall interaction is weaker and the heat release oscillations are driven by the flame area oscillations. The response of the flame to higher amplitude oscillations are used to gain further insight into the mechanisms. © 2010 Published by Elsevier Inc. on behalf of The Combustion Institute. All rights reserved.

  4. Flame surface statistics of constant-pressure turbulent expanding premixed flames

    Science.gov (United States)

    Saha, Abhishek; Chaudhuri, Swetaprovo; Law, Chung K.

    2014-04-01

    In this paper we investigate the local flame surface statistics of constant-pressure turbulent expanding flames. First the statistics of local length ratio is experimentally determined from high-speed planar Mie scattering images of spherically expanding flames, with the length ratio on the measurement plane, at predefined equiangular sectors, defined as the ratio of the actual flame length to the length of a circular-arc of radius equal to the average radius of the flame. Assuming isotropic distribution of such flame segments we then convolute suitable forms of the length-ratio probability distribution functions (pdfs) to arrive at the corresponding area-ratio pdfs. It is found that both the length ratio and area ratio pdfs are near log-normally distributed and shows self-similar behavior with increasing radius. Near log-normality and rather intermittent behavior of the flame-length ratio suggests similarity with dissipation rate quantities which stimulates multifractal analysis.

  5. Illustrating sensitivity in environmental fate models using partitioning maps - application to selected contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, T.; Wania, F. [Univ. of Toronto at Scarborough - DPES, Toronto (Canada)

    2004-09-15

    Generic environmental multimedia fate models are important tools in the assessment of the impact of organic pollutants. Because of limited possibilities to evaluate generic models by comparison with measured data and the increasing regulatory use of such models, uncertainties of model input and output are of considerable concern. This led to a demand for sensitivity and uncertainty analyses for the outputs of environmental fate models. Usually, variations of model predictions of the environmental fate of organic contaminants are analyzed for only one or at most a few selected chemicals, even though parameter sensitivity and contribution to uncertainty are widely different for different chemicals. We recently presented a graphical method that allows for the comprehensive investigation of model sensitivity and uncertainty for all neutral organic chemicals simultaneously. This is achieved by defining a two-dimensional hypothetical ''chemical space'' as a function of the equilibrium partition coefficients between air, water, and octanol (K{sub OW}, K{sub AW}, K{sub OA}), and plotting sensitivity and/or uncertainty of a specific model result to each input parameter as function of this chemical space. Here we show how such sensitivity maps can be used to quickly identify the variables with the highest influence on the environmental fate of selected, chlorobenzenes, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), hexachlorocyclohexanes (HCHs) and brominated flame retardents (BFRs).

  6. Simulations of flame generated particles

    KAUST Repository

    Patterson, Robert

    2016-01-05

    The nonlinear structure of the equations describing the evolution of a population of coagulating particles in a flame make the use of stochastic particle methods attractive for numerical purposes. I will present an analysis of the stochastic fluctuations inherent in these numerical methods leading to an efficient sampling technique for steady-state problems. I will also give some examples where stochastic particle methods have been used to explore the effect of uncertain parameters in soot formation models. In conclusion I will try to indicate some of the issues in optimising these methods for the study of uncertain model parameters.

  7. Simulations of flame generated particles

    KAUST Repository

    Patterson, Robert

    2016-01-01

    The nonlinear structure of the equations describing the evolution of a population of coagulating particles in a flame make the use of stochastic particle methods attractive for numerical purposes. I will present an analysis of the stochastic fluctuations inherent in these numerical methods leading to an efficient sampling technique for steady-state problems. I will also give some examples where stochastic particle methods have been used to explore the effect of uncertain parameters in soot formation models. In conclusion I will try to indicate some of the issues in optimising these methods for the study of uncertain model parameters.

  8. Nonequilibrium theory of flame propagation

    International Nuclear Information System (INIS)

    Merzhanov, A.G.

    1995-01-01

    The nonequilibrium theory of flame propagation is considered as applied to the following three processes of wave propagation: the combustion waves of the second kind, the combustion waves with broad reaction zones, and the combustion waves with chemical stages. Kinetic and combustion wave parameters are presented for different in composition mixtures of boron and transition metals, such as Zr, Hf, Ti, Nb, Ta, Mo, as well as for the Ta-N, Zr-C-H, Nb-B-O systems to illustrate specific features of the above-mentioned processes [ru

  9. Chemical processes in the HNF flame

    NARCIS (Netherlands)

    Ermolin, N.E.; Zarko, V.E.; Keizers, H.L.J.

    2006-01-01

    Results of modeling the HNF flame structure are presented. From an analysis of literature data on the thermal decomposition and combustion of HNF, it is concluded that the dissociative vaporization of HNF proceeds via the route HNFliq → (N2H4)g + (HC(NO 2)3)g. The flame structure is modeled using a

  10. Laser Doppler thermometry in flat flames

    NARCIS (Netherlands)

    Maaren, van A.; Goey, de L.P.H.

    1994-01-01

    Laser Doppler Velocimetry measurements are performed in flat flames, stabilized on a newly developed flat-flame burner. It is shown that the velocity component perpendicular to the main flow direction, induced by expansion in the reaction zone and buoyancy in the burnt gas, is significant. A method

  11. Development of PIV for Microgravity Diffusion Flames

    Science.gov (United States)

    Greenberg, Paul S.; Wernet, Mark P.; Yanis, William; Urban, David L.; Sunderland, Peter B.

    2003-01-01

    Results are presented from the application of Particle Image Velocimetry(PIV) to the overfire region of a laminar gas jet diffusion flame in normal gravity. A methane flame burning in air at 0.98 bar was considered. The apparatus demonstrated here is packaged in a drop rig designed for use in the 2.2 second drop tower.

  12. Contributions of BrCl, Br2, BrOCl, Br2O, and HOBr to regiospecific bromination rates of anisole and bromoanisoles in aqueous solution.

    Science.gov (United States)

    Sivey, John D; Bickley, Mark A; Victor, Daniel A

    2015-04-21

    When bromide-containing waters are chlorinated, conventional wisdom typically assumes HOBr is the only active brominating agent. Several additional and often-overlooked brominating agents (including BrCl, Br2, BrOCl, Br2O) can form in chlorinated waters, albeit at generally lower concentrations than HOBr. The extent to which these additional brominating agents influence bromination rates of disinfection byproduct precursors is, however, poorly understood. Herein, the influence of BrCl, Br2, BrOCl, Br2O, and HOBr toward rates of sequential bromination of anisole was quantified. Conditions affecting bromine speciation (e.g., pH, concentrations of chloride, bromide, and chlorine) were varied, and regiospecific second-order rate constants were calculated for reactions of each brominating agent with anisole, 2-bromoanisole, and 4-bromoanisole. The regioselectivity of anisole bromination changed with pH, consistent with the participation of more than one brominating agent. Under conditions representative of chlorinated drinking water, contributions to bromination rates decreased as BrCl > BrOCl > HOBr > Br2O (Br2 negligible). The second-order rate constant determined for net bromination of anisole by HOBr is up to 3000-times less than reported in previous studies (which assumed HOBr was the only active brominating agent). Accordingly, models that assume HOBr is the only kinetically relevant brominating agent in solutions of free bromine may be insufficient for reactions involving modestly nucleophilic organic compounds.

  13. Experimental quantification of transient stretch effects from vortices interacting with premixed flames

    Science.gov (United States)

    Danby, Sean James

    The understanding of complex premixed combustion reactions is paramount to the development of new concepts and devices used to increase the overall usefulness and capabilities of current technology. The complex interactions which occur within any modern practical combustion device were studied by isolating a single turbulent scale of the turbulence-chemistry interaction. Methane-air flame equivalence ratios (φ = 0.64, 0.90, and 1.13) were chosen to observe the mild affects of thermo-diffusive stability on the methane-air flame. Nitrogen was used as a diluent to retard the flame speeds of the φ = 0.90, and 1.13 mixtures so that the undisturbed outwardly propagating spherical flame kernel propagation rates, drf/dt, were approximately equal. Five primary propane equivalence ratios were utilized for investigation: φ = 0.69, 0.87, 1.08, 1.32, and 1.49. The choice of equivalence ratio was strategically made so that the φ = 0.69/1.49 and φ = 0.87/1.32 mixtures have the same undiluted flame propagation rate, drf/dt. Therefore, in the undiluted case, there are three flame speeds (in laboratory coordinates, not to be confused with burning velocity) represented by these mixtures. Three vortices were selected to be used in this investigation. The vortex rotational velocities were measured to be 77 cm/s, 266 cm/s and 398 cm/s for the "weak", "medium" and "strong" vortices, respectively. Ignition of the flame occurred in two ways: (1) spark-ignition or (2) laser ignition using an Nd:YAG laser at its second harmonic (lambda = 532 nm) in order to quantify the effect of electrode interference. Accompanying high-speed chemiluminescence imaging measurements, instantaneous pressure measurements were obtained to give a more detailed understanding of the effect of vortex strength on the overall flame speed and heat release rate over an extended time scale and to explore the use of a simple measurement to describe turbulent mixing. Further local flame-vortex interface analysis was

  14. Aerodynamic features of flames in premixed gases

    Science.gov (United States)

    Oppenheim, A. K.

    1984-01-01

    A variety of experimentally established flame phenomena in premixed gases are interpreted by relating them to basic aerodynamic properties of the flow field. On this basis the essential mechanism of some well known characteristic features of flames stabilized in the wake of a bluff-body or propagating in ducts are revealed. Elementary components of the flame propagation process are shown to be: rotary motion, self-advancement, and expansion. Their consequences are analyzed under a most strict set of idealizations that permit the flow field to be treated as potential in character, while the flame is modelled as a Stefan-like interface capable of exerting a feed-back effect upon the flow field. The results provide an insight into the fundamental fluid-mechanical reasons for the experimentally observed distortions of the flame front, rationalizing in particular its ability to sustain relatively high flow velocities at amazingly low normal burning speeds.

  15. Flame spread along thermally thick horizontal rods

    Science.gov (United States)

    Higuera, F. J.

    2002-06-01

    An analysis is carried out of the spread of a flame along a horizontal solid fuel rod, for which a weak aiding natural convection flow is established in the underside of the rod by the action of the axial gradient of the pressure variation that gravity generates in the warm gas surrounding the flame. The spread rate is determined in the limit of infinitely fast kinetics, taking into account the effect of radiative losses from the solid surface. The effect of a small inclination of the rod is discussed, pointing out a continuous transition between upward and downward flame spread. Flame spread along flat-bottomed solid cylinders, for which the gradient of the hydrostatically generated pressure drives the flow both along and across the direction of flame propagation, is also analysed.

  16. THE COMBINED EFFECT OF ORGANIC PHOSPHINATE BASED FLAME RETARDANT AND ZINC BORATE ON THE FIRE BEHAVIOR OF POLY(BUTYLENE TEREPHTHALATE

    Directory of Open Access Journals (Sweden)

    Mustafa Erdem ÜREYEN

    2016-12-01

    Full Text Available Neat poly(butylene terephthalate is highly combustible. It is not self-extinguishing, and after ignition it burns with dripping. To meet the fire safety requirements, it should be rendered flame retardant. The most common flame retardants for PBT are based on halogenated (most often brominated or phosphorus compounds. Although their efficiency is lower than halogen based flame retardants, expensive phosphorus based flame retardants for polyester are preferred, because of low smoke generation, nontoxicity and low corrosion properties. Zinc borate has been widely used with other flame retardants in wood products and in several polymers. In this work the fire behavior of zinc borate, phosphinic acid and zinc borate/phosphinic acid combination doped poly(butylene terephthalate was investigated. Firstly, the mean particle size of zinc borate (2ZnO.3B2O3.3.5H2O powders were reduced by attrition milling. Samples were produced by twin screw micro compounder. The fire properties of the ZnB, DPA and ZnB/DPA doped PBT were investigated and compared to each other by LOI and thermal analysis. LOI values of ZnB/PBT samples were found very low even with higher filling content. At higher loading of ZnB, the dripping of the sample strongly decreased and char residue increased. It was seen that organic diethyl phosphinic acid based additives DPA is particularly effective with PBT. It was found that the combination of DPA and ZnB can be used to increase the char residue, decrease spread of flame and the melt dripping of PBT.

  17. Kinetics of the reactions of bromine atoms with a series of aliphatic aldehydes at 298 K

    Energy Technology Data Exchange (ETDEWEB)

    Szilagyi, I.; Imrik, K.; Dobe, S.; Berces, T. [Magyar Tudomanyos Akademia, Budapest (Hungary). Koezponti Kemiai Kutato Intezete

    1998-01-01

    The kinetics of the reactions of Br({sup 2}P{sub 3/2}) with selected aldehydes, i.e. ethanal (1), propanal (2), 2-methyl-propanal (3), 2.2-dimethyl-propanal (4) and trichloroacetaldehyde (5) were studied at 298{+-}2 K. Rate constants for overall reactions were measured using the fast flow technique with resonance fluorescence detection of Br. Complementary determinations were carried out by the laser flash photolysis method. The following rate constants were obtained in the kinetic measurements ({+-}2{sigma}): k{sub 1}=(2.1{+-}0.2) x 10{sup 12}, k{sub 2}=(4.3{+-}0.4) x 10{sup 12}, k{sub 3}=(6.3{+-}1.4) x 10{sup 12}, k{sub 4}=(8.5{+-}0.8) x 10{sup 12}, k{sub 5}{<=}1 x 10{sup 9}, all in cm{sup 3}mol{sup -1}s{sup -1} units. The probable mechanism for the reactions of bromine atoms with aliphatic aldehydes has been discussed. (orig.)

  18. Photoelectron imaging spectroscopy for (2+1) resonance-enhanced multiphoton ionization of atomic bromine

    International Nuclear Information System (INIS)

    Kim, Yong Shin; Jung, Young Jae; Kang, Wee Kyung; Jung, Kyung Hoon

    2002-01-01

    Two-photon resonant third photon ionization of atomic bromine (4p 5 2 P 3/2 and 2 P 1/2 ) has been studied using a photoelectron imaging spectroscopy in the wavelength region 250-278 nm. The technique has yielded simultaneously both relative branching ratios to the three levels of Br + ( 3 P 2 , 3 P 0,1 and 1 D 2 ) with 4p 4 configuration and the angular distributions of outgoing photoelectrons. The product branching ratios reveal a strong propensity to populate particular levels in many cases. Several pathways have been documented for selective formation of Br + ( 3 P 2 ) and Br + ( 3 P 0,1 ) ions. In general, the final ion level distributions are dominated by the preservation of the ion core configuration of a resonant excited state. Some deviations from this simple picture are discussed in terms of the configuration interaction of resonant states and the autoionization in the continuum. The photoelectron angular distributions are qualitatively similar for all transitions, with a positive A 2 anisotropy coefficient of 1.0 - 2.0 and negligible A 4 in most cases, which suggests that the angular distribution is mainly determined by the single-photon ionization process of a resonant excited state induced from the third photon absorption

  19. Application of non-aqueous solvents to batteries. I Physicochemical properties of propionitrile/water two-phase solvent relevant to zinc-bromine batteries

    Science.gov (United States)

    Singh, P.; White, K.; Parker, A. J.

    1983-11-01

    The properties of bromine/propionitrile solution are investigated with a view to its use as an electrolyte in zinc-bromine batteries which use circulating electrolyte. The solution, which forms a two-phase system with water, has higher conductivity than the oils formed by complexation of bromine with organic salts such as N,N-methoxymethyl methylpiperidinium bromide and N,N-ethyl methylmorpholinium bromide. The activity of bromine in the aqueous phase of the bromine-propionitrile/water, two-phase system is very low; thus, coulombic efficiencies greater than 85 percent are achieved. Zinc-bromine batteries containing this solvent system show good charge/discharge characteristics.

  20. The modelling of direct chemical kinetic effects in turbulent flames

    Energy Technology Data Exchange (ETDEWEB)

    Lindstet, R.P. [Imperial College of Science, Technology and Medicine, London (United Kingdom). Dept. of Mechanical Engineering

    2000-06-01

    Combustion chemistry-related effects have traditionally been of secondary importance in the design of gas turbine combustors. However, the need to deal with issues such as flame stability, relight and pollutant emissions has served to bring chemical kinetics and the coupling of finite rate chemistry with turbulent flow fields to the centre of combustor design. Indeed, improved cycle efficiency and more stringent environmental legislation, as defined by the ICAO, are current key motivators in combustor design. Furthermore, lean premixed prevaporized (LPP) combustion systems, increasingly used for power generation, often operate close to the lean blow-off limit and are prone to extinction/reignition type phenomena. Thus, current key design issues require that direct chemical kinetic effects be accounted for accurately in any simulation procedure. The transported probability density function (PDF) approach uniquely offers the potential of facilitating the accurate modelling of such effects. The present paper thus assesses the ability of this technique to model kinetically controlled phenomena, such as carbon monoxide emissions and flame blow-off, through the application of a transported PDF method closed at the joint scalar level. The closure for the velocity field is at the second moment level, and a key feature of the present work is the use of comprehensive chemical kinetic mechanisms. The latter are derived from recent work by Lindstedt and co-workers that has resulted in a compact 141 reactions and 28 species mechanism for LNG combustion. The systematically reduced form used here features 14 independent C/H/O scalars, with the remaining species incorporated via steady state approximations. Computations have been performed for hydrogen/carbon dioxide and methane flames. The former (high Reynolds number) flames permit an assessment of the modelling of flame blow-off, and the methane flame has been selected to obtain an indication of the influence of differential

  1. Flame Structure and Emissions of Strongly-Pulsed Turbulent Diffusion Flames with Swirl

    Science.gov (United States)

    Liao, Ying-Hao

    This work studies the turbulent flame structure, the reaction-zone structure and the exhaust emissions of strongly-pulsed, non-premixed flames with co-flow swirl. The fuel injection is controlled by strongly-pulsing the fuel flow by a fast-response solenoid valve such that the fuel flow is completely shut off between pulses. This control strategy allows the fuel injection to be controlled over a wide range of operating conditions, allowing the flame structure to range from isolated fully-modulated puffs to interacting puffs to steady flames. The swirl level is controlled by varying the ratio of the volumetric flow rate of the tangential air to that of the axial air. For strongly-pulsed flames, both with and without swirl, the flame geometry is strongly impacted by the injection time. Flames appear to exhibit compact, puff-like structures for short injection times, while elongated flames, similar in behaviors to steady flames, occur for long injection times. The flames with swirl are found to be shorter for the same fuel injection conditions. The separation/interaction level between flame puffs in these flames is essentially governed by the jet-off time. The separation between flame puffs decreases as swirl is imposed, consistent with the decrease in flame puff celerity due to swirl. The decreased flame length and flame puff celerity are consistent with an increased rate of air entrainment due to swirl. The highest levels of CO emissions are generally found for compact, isolated flame puffs, consistent with the rapid quenching due to rapid dilution with excess air. The imposition of swirl generally results in a decrease in CO levels, suggesting more rapid and complete fuel/air mixing by imposing swirl in the co-flow stream. The levels of NO emissions for most cases are generally below the steady-flame value. The NO levels become comparable to the steady-flame value for sufficiently short jet-off time. The swirled co-flow air can, in some cases, increase the NO

  2. Experiment and Simulation of Autoignition in Jet Flames and its Relevance to Flame Stabilization and Structure

    KAUST Repository

    Al-Noman, Saeed M.

    2016-06-01

    Autoignition characteristics of pre-vaporized iso-octane, primary reference fuels, gasolines, and dimethyl ether (DME) have been investigated experimentally in a coflow with elevated temperature of air. With the coflow air at relatively low initial temperatures below autoignition temperature Tauto, an external ignition source was required to stabilize the flame. Non-autoignited lifted flames had tribrachial edge structures and their liftoff heights correlated well with the jet velocity scaled by the stoichiometric laminar burning velocity, indicating the importance of the edge propagation speed on flame stabilization balanced with local flow velocity. At high initial temperatures over Tauto, the autoignited flames were stabilized without requiring an external ignition source. The autoignited lifted flames exhibited either tribrachial edge structures or Mild combustion behaviors depending on the level of fuel dilution. For the iso-octane and n-heptane fuels, two distinct transition behaviors were observed in the autoignition regime from a nozzle-attached flame to a lifted tribrachial-edge flame and then a sudden transition to lifted Mild combustion as the jet velocity increased at a certain fuel dilution level. The liftoff data of the autoignited flames with tribrachial edges were analyzed based on calculated ignition delay times for the pre-vaporized fuels. Analysis of the experimental data suggested that ignition delay time may be much less sensitive to initial temperature under atmospheric pressure conditions as compared with predictions. For the gasoline fuels for advanced combustion engines (FACEs), and primary reference fuels (PRFs), autoignited liftoff data were correlated with Research Octane Number and Cetane Number. For the DME fuel, planar laser-induced fluorescence (PLIF) of formaldehyde (CH2O) and CH* chemiluminescence were visualized qualitatively. In the autoignition regime for both tribrachial structure and mild combustion, formaldehyde were found

  3. Analysis of flame shapes in turbulent hydrogen jet flames with coaxial air

    International Nuclear Information System (INIS)

    Moon, Hee Jang

    2009-01-01

    This paper addresses the characteristics of flame shapes and flame length in three types of coaxial air flames realizable by varying coaxial air and/or fuel velocity. Forcing coaxial air into turbulent jet flames induces substantial changes in flame shapes and NOx emissions through the complex flow interferences that exist within the mixing region. Mixing enhancement driven by coaxial air results in flame volume decrease, and such a diminished flame volume finally reduces NOx emissions significantly by decreasing NOx formation zone where a fuel/air mixture burns. It is found that mixing in the vicinity of high temperature zone mainly results from the increase of diffusive flux than the convective flux, and that the increase of mass diffusion is amplified as coaxial air is increased. Besides, it is reaffirmed that nonequilibrium chemistry including HO 2 /H 2 O 2 should be taken into account for NOx prediction and scaling analysis by comparing turbulent combustion models. In addition, it is found that coaxial air can break down the self-similarity law of flames by changing mixing mechanism, and that EINOx scaling parameters based on the self-similarity law of simple jet flames may not be eligible in coaxial air flames

  4. Analysis of flame shapes in turbulent hydrogen jet flames with coaxial air

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Hee Jang [Korea Aerospace University, Goyang (Korea, Republic of)

    2009-06-15

    This paper addresses the characteristics of flame shapes and flame length in three types of coaxial air flames realizable by varying coaxial air and/or fuel velocity. Forcing coaxial air into turbulent jet flames induces substantial changes in flame shapes and NOx emissions through the complex flow interferences that exist within the mixing region. Mixing enhancement driven by coaxial air results in flame volume decrease, and such a diminished flame volume finally reduces NOx emissions significantly by decreasing NOx formation zone where a fuel/air mixture burns. It is found that mixing in the vicinity of high temperature zone mainly results from the increase of diffusive flux than the convective flux, and that the increase of mass diffusion is amplified as coaxial air is increased. Besides, it is reaffirmed that nonequilibrium chemistry including HO{sub 2}/H{sub 2}O{sub 2} should be taken into account for NOx prediction and scaling analysis by comparing turbulent combustion models. In addition, it is found that coaxial air can break down the self-similarity law of flames by changing mixing mechanism, and that EINOx scaling parameters based on the self-similarity law of simple jet flames may not be eligible in coaxial air flames

  5. Thermal-diffusional Instability in White Dwarf Flames: Regimes of Flame Pulsation

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Guangzheng; Zhao, Yibo; Zhou, Cheng; Gao, Yang; Law, Chung K. [Center for Combustion Energy, Tsinghua University, Beijing 100084 (China); Modestov, Mikhail, E-mail: gaoyang-00@mails.tsinghua.edu.cn [Nordita, KTH Royal Institute of Technology and Stockholm University, SE-10691, Stockholm (Sweden)

    2017-05-20

    Thermal-diffusional pulsation behaviors in planar as well as outwardly and inwardly propagating white dwarf (WD) carbon flames are systematically studied. In the 1D numerical simulation, the asymptotic degenerate equation of state and simplified one-step reaction rates for nuclear reactions are used to study the flame propagation and pulsation in WDs. The numerical critical Zel’dovich numbers of planar flames at different densities ( ρ = 2, 3, and 4 × 10{sup 7} g cm{sup −3}) and of spherical flames (with curvature c = −0.01, 0, 0.01, and 0.05) at a particular density ( ρ = 2 × 10{sup 7} g cm{sup −3}) are presented. Flame front pulsation in different environmental densities and temperatures are obtained to form the regime diagram of pulsation, showing that carbon flames pulsate in the typical density of 2 × 10{sup 7} g cm{sup −3} and temperature of 0.6 × 10{sup 9} K. While being stable at higher temperatures, at relatively lower temperatures, the amplitude of the flame pulsation becomes larger. In outwardly propagating spherical flames the pulsation instability is enhanced and flames are also easier to quench due to pulsation at small radius, while the inwardly propagating flames are more stable.

  6. Narrow band flame emission from dieseline and diesel spray combustion in a constant volume combustion chamber

    KAUST Repository

    Wu, Zengyang

    2016-08-18

    In this paper, spray combustion of diesel (No. 2) and diesel-gasoline blend (dieseline: 80% diesel and 20% gasoline by volume) were investigated in an optically accessible constant volume combustion chamber. Effects of ambient conditions on flame emissions were studied. Ambient oxygen concentration was varied from 12% to 21% and three ambient temperatures were selected: 800 K, 1000 K and 1200 K. An intensified CCD camera coupled with bandpass filters was employed to capture the quasi-steady state flame emissions at 430 nm and 470 nm bands. Under non-sooting conditions, the narrow-band flame emissions at 430 nm and 470 nm can be used as indicators of CH∗ (methylidyne) and HCHO∗ (formaldehyde), respectively. The lift-off length was measured by imaging the OH∗ chemiluminescence at 310 nm. Flame emission structure and intensity distribution were compared between dieseline and diesel at wavelength bands. Flame emission images show that both narrow band emissions become shorter, thinner and stronger with higher oxygen concentration and higher ambient temperature for both fuels. Areas of weak intensity are observed at the flame periphery and the upstream for both fuels under all ambient conditions. Average flame emission intensity and area were calculated for 430 nm and 470 nm narrow-band emissions. At a lower ambient temperature the average intensity increases with increasing ambient oxygen concentration. However, at the 1200 K ambient temperature condition, the average intensity is not increasing monotonically for both fuels. For most of the conditions, diesel has a stronger average flame emission intensity than dieseline for the 430 nm band, and similar phenomena can be observed for the 470 nm band with 800 K and 1200 K ambient temperatures. However, for the 1000 K ambient temperature cases, dieseline has stronger average flame emission intensities than diesel for all oxygen concentrations at 470 nm band. Flame emissions for the two bands have a

  7. Biomagnification of polybrominated diphenyl ether and hexabromocyclododecane flame retardants in the polar bear food chain in Svalbard, Norway.

    Science.gov (United States)

    Sørmo, Eugen Gravningen; Salmer, Maria Pettersvik; Jenssen, Bjørn Munro; Hop, Haakon; Baek, Kine; Kovacs, Kit Maureen; Lydersen, Christian; Falk-Petersen, Stig; Gabrielsen, Geir Wing; Lie, Elisabeth; Skaare, Janneche Utne

    2006-09-01

    Concentrations of brominated flame retardants (BFRs), including polybrominated diphenylethers (PBDEs) and hexabromocyclododecane (HBCD), were investigated in an arctic marine food chain consisting of four invertebrate species: polar cod (Boreogadus saida), ringed seals (Pusa hispida), and polar bears (Ursus maritimus). The most abundant BFR, brominated diphenyl ether (BDE)-47, was found in detectable concentrations even in zooplankton, the lowest trophic level examined in this study. Most of the investigated BFRs biomagnified as function of tropic level in the food chain. A noticeable exception occurred at the highest trophic level, the polar bear, in which only BDE-153 was found to increase from its main prey, the ringed seal, indicating that polar bears appear to be able to metabolize and biodegrade most BFRs. In contrast, lower-brominated PBDEs, particularly BDE-47, showed clear signs of bioaccumulation in zooplankton, polar cod, and ringed seals. We suggest that this discrepancy in the fate of BFRs among the different species may be related to greater induction of oxidative detoxification activities in the polar bear. Absorption and debromination rates may be more important for bioaccumulation rates of BFRs in zooplankton, polar cod, and ringed seals. Lipid weight-based concentrations (LWCs) and whole body-based concentrations (WBCs) of BFRs were used to assess biomagnification factors (BMFs). Whole-body concentrations gave the most realistic BMFs, as BMFs derived from LWCs seem to be confounded by the large variability in lipid content of tissues from the investigated species. This study demonstrates that PBDEs and HBCD have reached measurable concentrations even in the lower trophic levels (invertebrates and fish) in the Arctic and biomagnifies in the polar bear food chain.

  8. Influence of the flame retardant tetrabromobisphenol-A on the expression of cytochrome P450 isoenzymes in rat liver

    Energy Technology Data Exchange (ETDEWEB)

    Germer, S.; Schmitz, H.J.; Schrenk, D. [Food Chemistry and Environmental Toxicology, Univ. of Kaiserslautern (Germany); Piersma, A.H.; Ven, L. van der [Lab. for Toxicology, Pathology and Genetics, National Inst. for Public Health and the Environment RIVM, Bilthoven (Netherlands)

    2004-09-15

    As one of the major brominated flame retardants (BFRs) tetrabromobisphenol A (TBBPA) is widely used in flammable plastic materials. There, it is incorporated either as covalently binding BFR or as an additive leading to likely leaching out of goods. Indeed, TBBPA was found in indoor air, environmental and human samples, i.e. mother's milk. Thus a certain degree of risk for human has to be considered. Some BFRs have been suspected to act as endocrine disrupters and/or affect the development of the unborn. Induction of drug metabolism may play a role in such effects by changing the body's homeostasis of hormones, such as steroids, thyroxine, and others. BFRs are prospected to lead to thyroid hormone deficiencies, neurodevelopmental deficiencies, cancer. Furthermore a variety of inducing agents have been described as tumor promoters in rodent liver. Herein the induction of enzymes of the cytochrome P450 family (CYP) plays a major role.

  9. An exemplary case of a bromine explosion event linked to cyclone development in the Arctic

    Directory of Open Access Journals (Sweden)

    A.-M. Blechschmidt

    2016-02-01

    Full Text Available Intense, cyclone-like shaped plumes of tropospheric bromine monoxide (BrO are regularly observed by GOME-2 on board the MetOp-A satellite over Arctic sea ice in polar spring. These plumes are often transported by high-latitude cyclones, sometimes over several days despite the short atmospheric lifetime of BrO. However, only few studies have focused on the role of polar weather systems in the development, duration and transport of tropospheric BrO plumes during bromine explosion events. The latter are caused by an autocatalytic chemical chain reaction associated with tropospheric ozone depletion and initiated by the release of bromine from cold brine-covered ice or snow to the atmosphere. In this manuscript, a case study investigating a comma-shaped BrO plume which developed over the Beaufort Sea and was observed by GOME-2 for several days is presented. By making combined use of satellite data and numerical models, it is shown that the occurrence of the plume was closely linked to frontal lifting in a polar cyclone and that it most likely resided in the lowest 3 km of the troposphere. In contrast to previous case studies, we demonstrate that the dry conveyor belt, a potentially bromine-rich stratospheric air stream which can complicate interpretation of satellite retrieved tropospheric BrO, is spatially separated from the observed BrO plume. It is concluded that weather conditions associated with the polar cyclone favoured the bromine activation cycle and blowing snow production, which may have acted as a bromine source during the bromine explosion event.

  10. Observations of bromine monoxide transport in the Arctic sustained on aerosol particles

    Directory of Open Access Journals (Sweden)

    P. K. Peterson

    2017-06-01

    Full Text Available The return of sunlight in the polar spring leads to the production of reactive halogen species from the surface snowpack, significantly altering the chemical composition of the Arctic near-surface atmosphere and the fate of long-range transported pollutants, including mercury. Recent work has shown the initial production of reactive bromine at the Arctic surface snowpack; however, we have limited knowledge of the vertical extent of this chemistry, as well as the lifetime and possible transport of reactive bromine aloft. Here, we present bromine monoxide (BrO and aerosol particle measurements obtained during the March 2012 BRomine Ozone Mercury EXperiment (BROMEX near Utqiaġvik (Barrow, AK. The airborne differential optical absorption spectroscopy (DOAS measurements provided an unprecedented level of spatial resolution, over 2 orders of magnitude greater than satellite observations and with vertical resolution unable to be achieved by satellite methods, for BrO in the Arctic. This novel method provided quantitative identification of a BrO plume, between 500 m and 1 km aloft, moving at the speed of the air mass. Concurrent aerosol particle measurements suggest that this lofted reactive bromine plume was transported and maintained at elevated levels through heterogeneous reactions on colocated supermicron aerosol particles, independent of surface snowpack bromine chemistry. This chemical transport mechanism explains the large spatial extents often observed for reactive bromine chemistry, which impacts atmospheric composition and pollutant fate across the Arctic region, beyond areas of initial snowpack halogen production. The possibility of BrO enhancements disconnected from the surface potentially contributes to sustaining BrO in the free troposphere and must also be considered in the interpretation of satellite BrO column observations, particularly in the context of the rapidly changing Arctic sea ice and snowpack.

  11. Role of heme in bromine-induced lung injury

    Science.gov (United States)

    Lam, Adam; Vetal, Nilam; Matalon, Sadis; Aggarwal, Saurabh

    2016-01-01

    Bromine (Br2) gas inhalation poses an environmental and occupational hazard resulting in high morbidity and mortality. In this review, we underline the acute lung pathology (within 24 hours of exposure) and potential therapeutic interventions that may be utilized to mitigate Br2-induced human toxicity. We will discuss our latest published data, which suggests that an increase in heme-dependent tissue injury underlies the pathogenesis of Br2 toxicity. Our study was based on previous findings that demonstrated that Br2 upregulates the heme-degrading enzyme heme oxygenase-1 (HO-1), which converts toxic heme into billiverdin. Interestingly, following Br2 inhalation, heme levels were indeed elevated in bronchoalveolar lavage fluid, plasma, and whole lung tissue in C57BL/6 mice. High heme levels correlated with increased lung oxidative stress, lung inflammation, respiratory acidosis, lung edema, higher airway resistance, and mortality. However, therapeutic reduction of heme levels, by either scavenging with hemopexin or degradation by HO-1, improved lung function and survival. Therefore, heme attenuation may prove a useful adjuvant therapy to treat patients after Br2 exposure. PMID:27244263

  12. Extended analysis of fifth spectrum of bromine: Br V

    Science.gov (United States)

    Riyaz, A.; Tauheed, A.; Rahimullah, K.

    2014-11-01

    The fifth spectrum of bromine (Br V) has been studied in the 200-2400 Å wavelength region. The spectrum was photographed on a 3-m normal incidence vacuum spectrograph at the St. Francis Xavier University, Antigonish (Canada) and 6.65-m grazing incidence spectrograph at the Zeeman laboratory (Amsterdam). The light sources used were a triggered spark and sliding spark. The ground configuration of Br V is 4s24p. The excited configurations 4s4p2+4s2(4d+5d+5s+6s+7s+5g+6g)+4s4p(5p+4f)+4p24d in the even parity system and the 4p3+4s2(5p+6p+7p+4f)+4s4p4d+4s4p5s configurations in the odd parity system have been studied. Relativistic Hartree-Fock (HFR) and least squares fitted (LSF) parametric calculations have been used to interpret the observed spectrum. 99 levels of Br V have now been established, 43 being new. Among 394 classified spectral lines, 181 are newly classified. The level 4s27s 2S1/2 is revised. We estimate the accuracy of our measured wavelengths for sharp and unblended lines to be±0.005 Å. The ionization limit is determined as 479,657±200 cm-1 (59.470±0.025 eV).

  13. Detection of Alkynes via Click Chemistry with a Brominated Coumarin Azide by Simultaneous Fluorescence and Isotopic Signatures in Mass Spectrometry.

    Science.gov (United States)

    Yang, Lihua; Chumsae, Chris; Kaplan, Jenifer B; Moulton, Kevin Ryan; Wang, Dongdong; Lee, David H; Zhou, Zhaohui Sunny

    2017-09-20

    Alkynes are a key component of click chemistry and used for a wide variety of applications including bioconjugation, selective tagging of protein modifications, and labeling of metabolites and drug targets. However, challenges still exist for detecting alkynes because most 1,2,3-triazole products from alkynes and azides do not possess distinct intrinsic properties that can be used for their facile detection by either fluorescence or mass spectrometry. To address this critical need, a novel brominated coumarin azide was used to tag alkynes and detect alkyne-conjugated biomolecules. This tag has several useful properties: first, it is fluorogenic and the click-chemistry products are highly fluorescent and quantifiable; second, its distinct isotopic pattern facilitates identification by mass spectrometry; and third, its click-chemistry products form a unique pair of reporter ions upon fragmentation that can be used for the quick screening of data. Using a monoclonal antibody conjugated with alkynes, a general workflow has been developed and examined comprehensively.

  14. Measurement-based modeling of bromine chemistry in the boundary layer: 1. Bromine chemistry at the Dead Sea

    Science.gov (United States)

    Tas, E.; Peleg, M.; Pedersen, D. U.; Matveev, V.; Pour Biazar, A.; Luria, M.

    2006-12-01

    The Dead Sea is an excellent natural laboratory for the investigation of Reactive Bromine Species (RBS) chemistry, due to the high RBS levels observed in this area, combined with anthropogenic air pollutants up to several ppb. The present study investigated the basic chemical mechanism of RBS at the Dead Sea using a numerical one-dimensional chemical model. Simulations were based on data obtained from comprehensive measurements performed at sites along the Dead Sea. The simulations showed that the high BrO levels measured frequently at the Dead Sea could only partially be attributed to the highly concentrated Br- present in the Dead Sea water. Furthermore, the RBS activity at the Dead Sea cannot solely be explained by a pure gas phase mechanism. This paper presents a chemical mechanism which can account for the observed chemical activity at the Dead Sea, with the addition of only two heterogeneous processes: the "Bromine Explosion" mechanism and the heterogeneous decomposition of BrONO2. Ozone frequently dropped below a threshold value of ~1 to 2 ppbv at the Dead Sea evaporation ponds, and in such cases, O3 became a limiting factor for the production of BrOx (BrO+Br). The entrainment of O3 fluxes into the evaporation ponds was found to be essential for the continuation of RBS activity, and to be the main reason for the jagged diurnal pattern of BrO observed in the Dead Sea area, and for the positive correlation observed between BrO and O3 at low O3 concentrations. The present study has shown that the heterogeneous decomposition of BrONO2 has a great potential to affect the RBS activity in areas influenced by anthropogenic emissions, mainly due to the positive correlation between the rate of this process and the levels of NO2. Further investigation of the influence of the decomposition of BrONO2 may be especially important in understanding the RBS activity at mid-latitudes.

  15. Measurement-based modeling of bromine chemistry in the boundary layer: 1. Bromine chemistry at the Dead Sea

    Directory of Open Access Journals (Sweden)

    E. Tas

    2006-01-01

    Full Text Available The Dead Sea is an excellent natural laboratory for the investigation of Reactive Bromine Species (RBS chemistry, due to the high RBS levels observed in this area, combined with anthropogenic air pollutants up to several ppb. The present study investigated the basic chemical mechanism of RBS at the Dead Sea using a numerical one-dimensional chemical model. Simulations were based on data obtained from comprehensive measurements performed at sites along the Dead Sea. The simulations showed that the high BrO levels measured frequently at the Dead Sea could only partially be attributed to the highly concentrated Br− present in the Dead Sea water. Furthermore, the RBS activity at the Dead Sea cannot solely be explained by a pure gas phase mechanism. This paper presents a chemical mechanism which can account for the observed chemical activity at the Dead Sea, with the addition of only two heterogeneous processes: the "Bromine Explosion" mechanism and the heterogeneous decomposition of BrONO2. Ozone frequently dropped below a threshold value of ~1 to 2 ppbv at the Dead Sea evaporation ponds, and in such cases, O3 became a limiting factor for the production of BrOx (BrO+Br. The entrainment of O3 fluxes into the evaporation ponds was found to be essential for the continuation of RBS activity, and to be the main reason for the jagged diurnal pattern of BrO observed in the Dead Sea area, and for the positive correlation observed between BrO and O3 at low O3 concentrations. The present study has shown that the heterogeneous decomposition of BrONO2 has a great potential to affect the RBS activity in areas influenced by anthropogenic emissions, mainly due to the positive correlation between the rate of this process and the levels of NO2. Further investigation of the influence of the decomposition of BrONO2 may be especially important in understanding the RBS activity at mid-latitudes.

  16. The FLAME project in Atomki

    International Nuclear Information System (INIS)

    Hunyadi, M.; Iski, N.

    2011-01-01

    Complete text of publication follows. Eleven regions of eight Central European countries have launched the FLAME Project in 2010 (Future Laboratory for the diffusion and Application of innovation in Material Sciences and Engineering) to start and manage a new initiative of a network for innovation activities in the MS and E sector. The project aimed at supporting actors in the field of materials science and exploiting their research and commercial potentials. FLAME partners encourage trans-regional cooperation between R and D centres, universities, start-ups and SMEs by helping companies to distribute their innovations and supporting research in transferring results to the market. The project will implement a new cooperation model: the 'Future Lab', where duly trained 'regional facilitation coaches' will assist SMEs in accessing the whole Central European MS and E market and research potential. Each Future Lab will be specialized on thematic fields and help to make efficient use of local and regional potentials. The three Future Labs will be hosted by the Austrian, Italian and Slovenian partner organizations. Figure 1. Competence and innovation landscape on the FLAME website. Source: http://www.flameurope.eu/mse-actors-145.html As the first step of project implementation in 2011 the competence and innovation maps within the participating regions were elaborated in order to list the relevant actors in the MS and E sector (Figure 1). In 2011, each project partner delegated two regional professionals as facilitation coaches to attend four training weeks across Europe. The facilitation coaches play an active role in the exchange of information and in motivating collaboration between research institutions and enterprises on technology based projects. The training sessions were located at four of the project partners: Kapfenberg/Austria (lead partner - Area m Styria); Warsaw/Poland (PP2 - Warsaw University of Technology); Debrecen/Hungary (PP5 - Atomki); Milan/Italy (PP

  17. The dilution effect on the extinction of wall diffusion flame

    Directory of Open Access Journals (Sweden)

    Ghiti Nadjib

    2014-12-01

    Full Text Available The dynamic process of the interaction between a turbulent jet diffusion methane flame and a lateral wall was experimentally studied. The evolution of the flame temperature field with the Nitrogen dilution of the methane jet flame was examined. The interaction between the diffusion flame and the lateral wall was investigated for different distance between the wall and the central axes of the jet flame. The dilution is found to play the central role in the flame extinction process. The flame response as the lateral wall approaches from infinity and the increasing of the dilution rate make the flame extinction more rapid than the flame without dilution, when the nitrogen dilution rate increase the flame temperature decrease.

  18. Prediction of flame formation in highly preheated air combustion

    International Nuclear Information System (INIS)

    Yang, Jang Sik; Choi, Gyung Min; Kim, Duck Jool; Katsuki, Masashi

    2008-01-01

    Fundamental information about the ignition position and shape of a flame in highly preheated air combustion was obtained, and the suitability of the suggested reduced kinetic mechanism that reflects the characteristics of the highly preheated air combustion was demonstrated. Flame lift height and flame length with variations of premixed air temperature and oxygen concentration were measured by CH chemiluminescence intensity, and were computed with a reduced kinetic mechanism. Flame attached near a fuel nozzle started to lift when preheated air temperature became close to auto-ignition temperature and/or oxygen concentration reduced. The flame lift height increased but the flame length decreased with decreasing preheated air temperature and flame length reversed after a minimum value. Calculated results showed good agreement with those of experiment within tolerable error. Flame shape shifted from diffusion flame shape to partial premixed flame shape with increasing lift height and this tendency was also observed in the computation results

  19. Prediction of flame formation in highly preheated air combustion

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jang Sik; Choi, Gyung Min; Kim, Duck Jool [Pusan National University, Busan (Korea, Republic of); Katsuki, Masashi [Osaka University, Osaka (Japan)

    2008-11-15

    Fundamental information about the ignition position and shape of a flame in highly preheated air combustion was obtained, and the suitability of the suggested reduced kinetic mechanism that reflects the characteristics of the highly preheated air combustion was demonstrated. Flame lift height and flame length with variations of premixed air temperature and oxygen concentration were measured by CH chemiluminescence intensity, and were computed with a reduced kinetic mechanism. Flame attached near a fuel nozzle started to lift when preheated air temperature became close to auto-ignition temperature and/or oxygen concentration reduced. The flame lift height increased but the flame length decreased with decreasing preheated air temperature and flame length reversed after a minimum value. Calculated results showed good agreement with those of experiment within tolerable error. Flame shape shifted from diffusion flame shape to partial premixed flame shape with increasing lift height and this tendency was also observed in the computation results

  20. Flame Speed and Self-Similar Propagation of Expanding Turbulent Premixed Flames

    Science.gov (United States)

    Chaudhuri, Swetaprovo; Wu, Fujia; Zhu, Delin; Law, Chung K.

    2012-01-01

    In this Letter we present turbulent flame speeds and their scaling from experimental measurements on constant-pressure, unity Lewis number expanding turbulent flames, propagating in nearly homogeneous isotropic turbulence in a dual-chamber, fan-stirred vessel. It is found that the normalized turbulent flame speed as a function of the average radius scales as a turbulent Reynolds number to the one-half power, where the average radius is the length scale and the thermal diffusivity is the transport property, thus showing self-similar propagation. Utilizing this dependence it is found that the turbulent flame speeds from the present expanding flames and those from the Bunsen geometry in the literature can be unified by a turbulent Reynolds number based on flame length scales using recent theoretical results obtained by spectral closure of the transformed G equation.

  1. Systems and methods for controlling flame instability

    KAUST Repository

    Cha, Min Suk

    2016-07-21

    A system (62) for controlling flame instability comprising: a nozzle (66) coupled to a fuel supply line (70), an insulation housing (74) coupled to the nozzle, a combustor (78) coupled to the nozzle via the insulation housing, where the combustor is grounded (80), a pressure sensor (82) coupled to the combustor and configured to detect pressure in the combustor, and an instability controlling assembly coupled to the pressure sensor and to an alternating current power supply (86), where, the instability controlling assembly can control flame instability of a flame in the system based on pressure detected by the pressure sensor.

  2. Aromatics oxidation and soot formation in flames

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J.B.; Pope, C.J.; Shandross, R.A.; Yadav, T. [Massachusetts Institute of Technology, Cambridge (United States)

    1993-12-01

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and soot and fullerenes formation in flames. The scope includes detailed measurements of profiles of stable and radical species concentrations in low-pressure one-dimensional premixed flames. Intermediate species identifications and mole fractions, fluxes, and net reaction rates calculated from the measured profiles are used to test postulated reaction mechanisms. Particular objectives are to identify and to determine or confirm rate constants for the main benzene oxidation reactions in flames, and to characterize fullerenes and their formation mechanisms and kinetics.

  3. The determination of the rare earth elements in naturally-occurring materials zy flame spectroscopy

    International Nuclear Information System (INIS)

    Watts, J.C.

    1975-01-01

    Because the quantitative collection of the rare-earth elements retains natural abundance ratios, adequate analytical methodology incorporates their individual sensitivities, and tolerates their mutual contamination. To achieve these ends, the sensitivities of 15 rare-earths in flame emission were determined in the unseparated nitrous oxide/acetylene flame, their mutual interference ascertained at practical concentrations, and useful emission lines selected for their determination in natural materials. Sources of atomic emission interference were extraneous in origin. Fe in the determination of Dy and Zr in the determination of Nd. Inter-element interferences of the rare-earth elements were minimal after wavelength selection and reduction of the spectral band width. For comparison, five rare earths were determined by flame AAS. (author)

  4. Structure of diffusion flames from a vertical burner

    Science.gov (United States)

    Mark A. Finney; Dan Jimenez; Jack D. Cohen; Isaac C. Grenfell; Cyle Wold

    2010-01-01

    Non-steady and turbulent flames are commonly observed to produce flame contacts with adjacent fuels during fire spread in a wide range of fuel bed depths. A stationary gas-fired burner (flame wall) was developed to begin study of flame edge variability along an analagous vertical fuel source. This flame wall is surrogate for a combustion interface at the edge of a deep...

  5. Direct numerical simulations of non-premixed ethylene-air flames: Local flame extinction criterion

    KAUST Repository

    Lecoustre, Vivien R.

    2014-11-01

    Direct Numerical Simulations (DNS) of ethylene/air diffusion flame extinctions in decaying two-dimensional turbulence were performed. A Damköhler-number-based flame extinction criterion as provided by classical large activation energy asymptotic (AEA) theory is assessed for its validity in predicting flame extinction and compared to one based on Chemical Explosive Mode Analysis (CEMA) of the detailed chemistry. The DNS code solves compressible flow conservation equations using high order finite difference and explicit time integration schemes. The ethylene/air chemistry is simulated with a reduced mechanism that is generated based on the directed relation graph (DRG) based methods along with stiffness removal. The numerical configuration is an ethylene fuel strip embedded in ambient air and exposed to a prescribed decaying turbulent flow field. The emphasis of this study is on the several flame extinction events observed in contrived parametric simulations. A modified viscosity and changing pressure (MVCP) scheme was adopted in order to artificially manipulate the probability of flame extinction. Using MVCP, pressure was changed from the baseline case of 1 atm to 0.1 and 10 atm. In the high pressure MVCP case, the simulated flame is extinction-free, whereas in the low pressure MVCP case, the simulated flame features frequent extinction events and is close to global extinction. Results show that, despite its relative simplicity and provided that the global flame activation temperature is correctly calibrated, the AEA-based flame extinction criterion can accurately predict the simulated flame extinction events. It is also found that the AEA-based criterion provides predictions of flame extinction that are consistent with those provided by a CEMA-based criterion. This study supports the validity of a simple Damköhler-number-based criterion to predict flame extinction in engineering-level CFD models. © 2014 The Combustion Institute.

  6. Utilization of oxidation reactions for the spectrophotometric determination of captopril using brominating agents

    Science.gov (United States)

    El-Didamony, Akram M.; Erfan, Eman A. H.

    2010-03-01

    Three simple, accurate and sensitive methods (A-C) for the spectrophotometric assay of captopril (CPL) in bulk drug, in dosage forms and in the presence of its oxidative degradates have been described. The methods are based on the bromination of captopril with a solution of excess brominating mixture in hydrochloric acid medium. After bromination, the excess brominating mixture is followed by the estimation of surplus bromine by three different reaction schemes. In the first method (A), the determination of the residual bromine is based on its ability to bleach the indigo carmine dye and measuring the absorbance at 610 nm. Method B, involves treating the unreacted bromine with a measured excess of iron(II) and the remaining iron(II) is complexed with 1,10-phenanthroline and the increase in absorbance is measured at 510 nm. In method (C), the surplus bromine is treated with excess of iron(II) and the resulting iron(III) is complexed with thiocyanate and the absorbance is measured at 478 nm. In all the methods, the amount of bromine reacted corresponds to the drug content. The different experimental parameters affecting the development and stability of the color are carefully studied and optimized. Beer's law is valid within a concentration range of 0.4-6.0, 0.4-2.8 and 1.2-4.8 μg mL -1 for methods A, B and C, respectively. The calculated apparent molar absorptivity was found to be 5.16 × 10 4, 9.95 × 10 4 and 1.74 × 10 5 L mol -1 cm -1, for methods A, B and C, respectively. Sandell's sensitivity, correlation coefficients, detection and quantification limits are also reported. No interference was observed from common additives found in pharmaceutical preparations. The proposed methods are successfully applied to the determination of CPL in the tablet formulations with mean recoveries of 99.94-100.11% and the results were statistically compared with those of a reference method by applying Student's t- and F-test.

  7. Sea ice and pollution-modulated changes in Greenland ice core methanesulfonate and bromine

    Science.gov (United States)

    Maselli, Olivia J.; Chellman, Nathan J.; Grieman, Mackenzie; Layman, Lawrence; McConnell, Joseph R.; Pasteris, Daniel; Rhodes, Rachael H.; Saltzman, Eric; Sigl, Michael

    2017-01-01

    Reconstruction of past changes in Arctic sea ice extent may be critical for understanding its future evolution. Methanesulfonate (MSA) and bromine concentrations preserved in ice cores have both been proposed as indicators of past sea ice conditions. In this study, two ice cores from central and north-eastern Greenland were analysed at sub-annual resolution for MSA (CH3SO3H) and bromine, covering the time period 1750-2010. We examine correlations between ice core MSA and the HadISST1 ICE sea ice dataset and consult back trajectories to infer the likely source regions. A strong correlation between the low-frequency MSA and bromine records during pre-industrial times indicates that both chemical species are likely linked to processes occurring on or near sea ice in the same source regions. The positive correlation between ice core MSA and bromine persists until the mid-20th century, when the acidity of Greenland ice begins to increase markedly due to increased fossil fuel emissions. After that time, MSA levels decrease as a result of declining sea ice extent but bromine levels increase. We consider several possible explanations and ultimately suggest that increased acidity, specifically nitric acid, of snow on sea ice stimulates the release of reactive Br from sea ice, resulting in increased transport and deposition on the Greenland ice sheet.

  8. Brominated Skeletal Components of the Marine Demosponges, Aplysina cavernicola and Ianthella basta: Analytical and Biochemical Investigations

    Directory of Open Access Journals (Sweden)

    Eike Brunner

    2013-04-01

    Full Text Available Demosponges possess a skeleton made of a composite material with various organic constituents and/or siliceous spicules. Chitin is an integral part of the skeleton of different sponges of the order Verongida. Moreover, sponges of the order Verongida, such as Aplysina cavernicola or Ianthella basta, are well-known for the biosynthesis of brominated tyrosine derivates, characteristic bioactive natural products. It has been unknown so far whether these compounds are exclusively present in the cellular matrix or whether they may also be incorporated into the chitin-based skeletons. In the present study, we therefore examined the skeletons of A. cavernicola and I. basta with respect to the presence of bromotyrosine metabolites. The chitin-based-skeletons isolated from these sponges indeed contain significant amounts of brominated compounds, which are not easily extractable from the skeletons by common solvents, such as MeOH, as shown by HPLC analyses in combination with NMR and IR spectroscopic measurements. Quantitative potentiometric analyses confirm that the skeleton-associated bromine mainly withstands the MeOH-based extraction. This observation suggests that the respective, but yet unidentified, brominated compounds are strongly bound to the sponge skeletons, possibly by covalent bonding. Moreover, gene fragments of halogenases suggested to be responsible for the incorporation of bromine into organic molecules could be amplified from DNA isolated from sponge samples enriched for sponge-associated bacteria.

  9. Effect of cylindrical confinement on the determination of laminar flame speeds using outwardly propagating flames

    Energy Technology Data Exchange (ETDEWEB)

    Burke, Michael P.; Chen, Zheng; Ju, Yiguang; Dryer, Frederick L. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

    2009-04-15

    The effect of nonspherical (i.e. cylindrical) bomb geometry on the evolution of outwardly propagating flames and the determination of laminar flame speeds using the conventional constant-pressure technique is investigated experimentally and theoretically. The cylindrical chamber boundary modifies the propagation rate through the interaction of the wall with the flow induced by thermal expansion across the flame (even with constant pressure), which leads to significant distortion of the flame surface for large flame radii. These departures from the unconfined case, especially the resulting nonzero burned gas velocities, can lead to significant errors in flame speeds calculated using the conventional assumptions, especially for large flame radii. For example, at a flame radius of 0.5 times the wall radius, the flame speed calculated neglecting confinement effects can be low by {proportional_to}15% (even with constant pressure). A methodology to estimate the effect of nonzero burned gas velocities on the measured flame speed in cylindrical chambers is presented. Modeling and experiments indicate that the effect of confinement can be neglected for flame radii less than 0.3 times the wall radius while still achieving acceptable accuracy (within 3%). The methodology is applied to correct the flame speed for nonzero burned gas speeds, in order to extend the range of flame radii useful for flame speed measurements. Under the proposed scaling, the burned gas speed can be well approximated as a function of only flame radius for a given chamber geometry - i.e. the correction function need only be determined once for an apparatus and then it can be used for any mixture. Results indicate that the flow correction can be used to extract flame speeds for flame radii up to 0.5 times the wall radius with somewhat larger, yet still acceptable uncertainties for the cases studied. Flow-corrected burning velocities are measured for hydrogen and syngas mixtures at atmospheric and

  10. Comparison of in vitro hormone activities of novel flame retardants TBB, TBPH and their metabolites TBBA and TBMEPH using reporter gene assays.

    Science.gov (United States)

    Klopčič, Ivana; Skledar, Darja Gramec; Mašič, Lucija Peterlin; Dolenc, Marija Sollner

    2016-10-01

    The anti-androgenic and anti-thyroid hormonal activities of the two novel brominated flame retardants, TBB and TBPH and of their metabolites TBBA and TBMEPH have been compared using the luciferase reporter gene assays. Only the parent compounds TBB and TBPH exhibited anti-glucocorticoid activity with IC50 values of 1.9 μM and 0.3 μM. Furthermore, mode of action for these two compounds is by direct competing to the glucocorticoid receptor (GR) with IC50 values of 0.03 μM and 0.002 μM. All four tested compounds possess anti-androgenic and anti-thyroid hormonal activities, without agonist activities on the respective receptors. Anti-androgenic activities with IC50 values of 43.5 μM, 0.1 μM, 47.5 μM and 1.3 μM were found for TBB, TBPH, TBBA and TBMEPH. The anti-thyroid hormonal IC50 values of 37.5 μM, 0.1 μM, 22.8 μM and 32.3 μM for TBB, TBPH, TBBA and TBMEPH, together with the above quoted results, indicate that metabolism can modify anti-androgenic, anti-glucocorticoid and anti-thyroid hormonal effects of these novel brominated flame retardants. Furthermore, the parent flame retardants are shown to be able to disrupt the function of the GR as antagonists by direct competition to the receptor. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Aromatics Oxidation and Soot Formation in Flames

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J. B.; Richter, H.

    2005-03-29

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and the growth process to polycyclic aromatic hydrocarbons (PAH) of increasing size, soot and fullerenes formation in flames. The overall objective of the experimental aromatics oxidation work is to extend the set of available data by measuring concentration profiles for decomposition intermediates such as phenyl, cyclopentadienyl, phenoxy or indenyl radicals which could not be measured with molecular-beam mass spectrometry to permit further refinement and testing of benzene oxidation mechanisms. The focus includes PAH radicals which are thought to play a major role in the soot formation process while their concentrations are in many cases too low to permit measurement with conventional mass spectrometry. The radical species measurements are used in critical testing and improvement of a kinetic model describing benzene oxidation and PAH growth. Thermodynamic property data of selected species are determined computationally, for instance using density functional theory (DFT). Potential energy surfaces are explored in order to identify additional reaction pathways. The ultimate goal is to understand the conversion of high molecular weight compounds to nascent soot particles, to assess the roles of planar and curved PAH and relationships between soot and fullerenes formation. The specific aims are to characterize both the high molecular weight compounds involved in the nucleation of soot particles and the structure of soot including internal nanoscale features indicative of contributions of planar and/or curved PAH to particle inception.

  12. Characterization of bromine-76-labelled 5-bromo-6-nitroquipazine for PET studies of the serotonin transporter

    Energy Technology Data Exchange (ETDEWEB)

    Lundkvist, Camilla E-mail: Lundkvis@shfj.cea.fr; Loc' h, Christian; Halldin, Christer; Bottlaender, Michel; Ottaviani, Michele; Coulon, Christine; Fuseau, Chantal; Mathis, Chester; Farde, Lars; Maziere, Bernard

    1999-07-01

    The development of suitable radioligands for brain imaging of the serotonin transporter is of great importance for the study of depression and other affective disorders. The potent and selective serotonin transporter ligand, 5-iodo-6-nitro-2-piperazinylquinoline, has been labelled with iodine-123 and used as a radioligand for single photon emission computerized tomography. To evaluate the potential of the bromine-76-labelled analogue, 5-bromo-6-nitroquipazine, as a radioligand for positron emission tomography (PET), its brain distribution and binding characteristics were examined in rats. In vivo brain distribution and ex vivo autoradiography demonstrated that [{sup 76}Br]5-bromo-6-nitroquipazine enters the brain rapidly. The regional brain distribution of [{sup 76}Br]5-bromo-6-nitroquipazine was consistent with the known distribution of serotonin transporters in the midbrain, pons, thalamus, striatum, and neocortex. Specific binding was inhibited by the selective serotonin reuptake inhibitor citalopram. The peripheral metabolism in plasma was rapid, but more than 90% of the radioactivity in brain represented unchanged radioligand 2 h postinjection (p.i.). A preliminary PET study was also performed in a baboon. Following the intravenous injection of [{sup 76}Br]5-bromo-6-nitroquipazine in a baboon, there was a conspicuous accumulation of radioactivity in thalamus, striatum, and pons. The radioactivity in these brain regions was 1.5 times higher than in the cerebellum at 3 h and 2.5-4 times higher at 24 h. A rapid metabolism of the radioligand in plasma was observed (38% unchanged after 5 min). The results indicate that [{sup 76}Br]5-bromo-6-nitroquipazine has potential for PET imaging of the serotonin transporter.

  13. Gas-Flame Brazing of Metals

    National Research Council Canada - National Science Library

    Asinovskaya, G

    1964-01-01

    .... Since a gas flame implies the presence of considerable heat, the term brazing will be used in this translation save where low heats are specifically indicated, or where both high and low heats...

  14. Systems and methods for controlling flame instability

    KAUST Repository

    Cha, Min; Xiong, Yuan; Chung, Suk-Ho

    2016-01-01

    A system (62) for controlling flame instability comprising: a nozzle (66) coupled to a fuel supply line (70), an insulation housing (74) coupled to the nozzle, a combustor (78) coupled to the nozzle via the insulation housing, where the combustor

  15. Distribution of electric potential in hydrocarbon flames

    Energy Technology Data Exchange (ETDEWEB)

    Fialkov, B.S.; Shcherbakov, N.D.; Plitsyn, V.T.

    1978-01-01

    A study was made of the distribution of electrical potential and temperatures in laminar methane and propane--butane flames when the excess air coefficient in the mixture is changed from 0 to 1.2. 7 references, 3 figures.

  16. CloudFlame: Cyberinfrastructure for combustion research

    KAUST Repository

    Goteng, Gokop; Nettyam, Naveena; Sarathy, Mani

    2013-01-01

    Combustion experiments and chemical kinetics simulations generate huge data that is computationally and data intensive. A cloud-based cyber infrastructure known as Cloud Flame is implemented to improve the computational efficiency, scalability

  17. Synthesis of Nano-Particles in Flames

    DEFF Research Database (Denmark)

    Johannessen, Tue

    flame burner and a premixed burner with a precursor jet. The experimental setups and results are shown and discussed in detail. Alumina powder with specific surface area between 45 m2/g and 190 m2/g was obtained.Temperature and flow fields of the flame processes are analysed by numerical simulations...... energy expression.Furthermore, the model is validated by comparison with experimental data of the flame synthesis of titania by combustion of TiCl4 previously presented by Pratsinis et al. (1996).The combination of particle dynamics and CFD simulations has proved to be an efficient method......The scope of this work is to investigate the synthesis of aluminum oxide particles in flames from the combustion of an aluminum alkoxide precursor.A general introduction to particles formation in the gas phase is presented with emphasis on the mechanisms that control the particle morphology after...

  18. Numerical modelling of ion transport in flames

    KAUST Repository

    Han, Jie; Belhi, Memdouh; Bisetti, Fabrizio; Sarathy, Mani

    2015-01-01

    that changes in polarizability propagate with decreasing effect from binary transport coefficients to species number densities. We conclude that the chosen polarizability value has a limited effect on the ion distribution in freely propagating flames. We expect

  19. Understanding the interactions of phosphonate-based flame-retarding additives with graphitic anode for lithium ion batteries

    International Nuclear Information System (INIS)

    Feng, Jinkui; Ma, Peng; Yang, Hanxi; Lu, Li

    2013-01-01

    Highlights: •Diethyl ethylphosphonate (DEEP) and dimethyl methylphosphonate are tested as flame retardants for lithium ion batteries. •The DMMP shows a destructive reaction with graphitic anode while DEEP shows a self-reduction mechanism. •DEEP is reported for the first time as flame-retardant additive for lithium ion batteries and demonstrates a much better compatibility with graphitic anode. -- Abstract: The compatibility with graphitic anode has been one key problem in developing flame-retarding additives for lithium ion batteries. To understand the interactions between flame-retarding additives and graphitic anode, two phosphonate esters (dimethyl methylphosphonate DMMP and diethyl ethylphosphonate DEEP) are selected and characterized as flame retardant addtives. DEEP is reported as a flame-retarding additive for the first time. Their interactions with graphite anode are characterized via current-static charge–discharge, ex-situ XRD, FE-SEM and AC impedance. The results reveal that the two phosphonate esters demonstrate different reaction mechanisms with graphitic anode, which result in different anode compatibility. These findings may be useful for designing better flame-retarding additives for lithium ion batteries

  20. Characterization of flame radiosity in shrubland fires

    Science.gov (United States)

    Miguel G. Cruz; Bret W. Butler; Domingos X. Viegas; Pedro Palheiro

    2011-01-01

    The present study is aimed at quantifying the flame radiosity vertical profile and gas temperature in moderate to high intensity spreading fires in shrubland fuels. We report on the results from 11 experimental fires conducted over a range of fire rate of spread and frontal fire intensity varying respectively between 0.04-0.35ms-1 and 468-14,973kWm-1. Flame radiosity,...

  1. Comparison between Two Bromine Containing Free Radical Initiators in PRESAGE®

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyeonsuk; Ryu, Dongmin; Ye, Sung-Joon [Seoul National University, Seoul (Korea, Republic of)

    2016-10-15

    PRESAGE® is an optically clear 3-D polyurethane dosimeter which contains a halogenated carbon as a free radical initiator and leucomalachite dye. The change of the optical density is known to be linear with respect to the absorbed dose and the sensitivity is related to the carbon–halogen bond dissociation energy of the free radical initiator. Although there are some studies regarding free radical initiators and dye materials, there’s a lack of reports about the effect of other elements like LMG solvent which can be added when there’s a difficulty mixing materials. Also, there are some studies about comparison between free radicals with different kind of halogen atoms but there’s a lack of studies of comparison between initiators with the same halogen atom. In this experiments, two kinds of halocarbon free radical initiator with the same halogen atom (bromine) as well as the effect of the LMG solvent were studied to use the dosimeter as a therapeutic purpose. Effective atomic numbers were also calculated. The initiators with the same halogen atom, CBr{sub 4} and C{sub 2}H{sub 2}Br{sub 4}, reacted totally differently. CBr{sub 4} was more sensitive to the radiation and emitted maximum 4 times more free radicals upon irradiation with no additional effective atomic number but the absorbance after irradiation was highly variable with time. For stable measurement, C{sub 2}H{sub 2}Br{sub 4} would be more appropriate as a free radical initiator.

  2. Extended analysis of fifth spectrum of bromine: Br V

    International Nuclear Information System (INIS)

    Riyaz, A.; Tauheed, A.; Rahimullah, K.

    2014-01-01

    The fifth spectrum of bromine (Br V) has been studied in the 200–2400 Å wavelength region. The spectrum was photographed on a 3-m normal incidence vacuum spectrograph at the St. Francis Xavier University, Antigonish (Canada) and 6.65-m grazing incidence spectrograph at the Zeeman laboratory (Amsterdam). The light sources used were a triggered spark and sliding spark. The ground configuration of Br V is 4s 2 4p. The excited configurations 4s4p 2 +4s 2 (4d+5d+5s+6s+7s+5g+6g)+4s4p(5p+4f)+4p 2 4d in the even parity system and the 4p 3 +4s 2 (5p+6p+7p+4f)+4s4p4d+4s4p5s configurations in the odd parity system have been studied. Relativistic Hartree–Fock (HFR) and least squares fitted (LSF) parametric calculations have been used to interpret the observed spectrum. 99 levels of Br V have now been established, 43 being new. Among 394 classified spectral lines, 181 are newly classified. The level 4s 2 7s 2 S 1/2 is revised. We estimate the accuracy of our measured wavelengths for sharp and unblended lines to be±0.005 Å. The ionization limit is determined as 479,657±200 cm −1 (59.470±0.025 eV). - Highlights: • The spectrum of Br was recorded on a 3-m spectrograph with triggered spark source. • Atomic transitions for Br V were identified to established new energy levels. • CI calculations with relativistic corrections were made for theoretical predictions. • Weighted oscillator strength (gf) and transition probabilities (gA) were calculated. • Ionization potential of Br V was determined experimentally

  3. Occurrence and source apportionment of halogenated flame retardants in the indoor air of Nepalese cities: Implication on human health

    Science.gov (United States)

    Yadav, Ishwar Chandra; Devi, Ningombam Linthoingmabi; Li, Jun; Zhang, Gan

    2017-07-01

    Elevated level of brominated- and chlorinated-flame retardants (FRs) have been accounted in ambient air across the globe. Despite what might be expected, restricted information is available on PBDEs and other halogenated FR contained indoor air in whole of Indian sub-continent especially in case of Nepal, sandwiched between two most populous countries i.e. India and China. It was conjectured that the level of halogenated flame retardant (HFRs) in Nepalese air would be high because they have not been liable to control in Nepal; and henceforth there is more plausibility of HFRs to be available in a diverse array of goods and consumer products. This study therefore aims to measure the occurrence, spatial distributions and sources of 15 brominated- and 2 chlorinated-FRs in indoor air from four major cities of Nepal. The overall concentrations of HFRs ranged from 16.1 to 6750 pg/m3 (median 334 pg/m3). The total concentrations of novel brominated fire retardants (NBFRs) were 20 and 100 times (13.2-6270 pg/m3) higher than PBDEs (2.2-353 pg/m3) and DPs (0.67-129 pg/m3), respectively indicating much higher usages of NBFRs in Nepal. The level of ∑PBDEs in air is identified with utilization of wide variety of consumers products and building materials containing FRs in Nepalese houses, while higher concentration of BDE-209 were subject to emission from materials containing deca-BDE formulation. Significantly higher concentrations of DBDPE than BDE-209 in air demonstrated a move to more prominent use of DBDPE as alternative to BDE-209. The lower fanti ratios suggests the DP level in this study was essentially affected by the long range atmospheric transport from remote DP source instead of commercial products. The exposure to BDE-47, -99, -153, -209 and HBB via inhalation was 3-4 orders of magnitude lower than corresponding RfD values, suggesting insignificant risk to Nepalese population. However, other modes of human exposure might still be significant in Nepal.

  4. NO concentration imaging in turbulent nonpremixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Schefer, R.W. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The importance of NO as a pollutant species is well known. An understanding of the formation characteristics of NO in turbulent hydrocarbon flames is important to both the desired reduction of pollutant emissions and the validation of proposed models for turbulent reacting flows. Of particular interest is the relationship between NO formation and the local flame zone, in which the fuel is oxidized and primary heat release occurs. Planar imaging of NO provides the multipoint statistics needed to relate NO formation to the both the flame zone and the local turbulence characteristics. Planar imaging of NO has been demonstrated in turbulent flames where NO was seeded into the flow at high concentrations (2000 ppm) to determine the gas temperature distribution. The NO concentrations in these experiments were significantly higher than those expected in typical hydrocarbon-air flames, which require a much lower detectability limit for NO measurements. An imaging technique based on laser-induced fluorescence with sufficient sensitivity to study the NO formation mechanism in the stabilization region of turbulent lifted-jet methane flames.

  5. Bromine-77-labeled estrogen receptor-binding radiopharmaceuticals for breast tumor imaging

    International Nuclear Information System (INIS)

    McElvany, K.D.

    1985-01-01

    Two derivatives of 16α-bromoestradiol, both with and without an 11β-methoxy substituent, have been labeled with bromine-77 and evaluated as potential breast tumor imaging agents. Extensive characterization of these radiotracers in animal models has demonstrated their effective concentration in estrogen target tissues. Preliminary clinical studies have demonstrated the potential of radiolabeled estrogens for breast tumor imaging; however, the suboptimal decay properties of bromine-77 limit the utility of these agents in imaging studies. These results with 77 -Br-labeled estrogens suggest that estrogen derivatives labeled with other radionuclides should provide enhanced image resolution with various imaging devices. Although the decay characteristics of bromine-77 are such that it is not ideally suited to imaging with conventional gamma cameras, it may be a useful radionuclide for therapeutic applications

  6. Determination by neutron activation analysis of loss of arsenic, antimony, bromine and mercury during lyophilization

    International Nuclear Information System (INIS)

    Carlson, M.; Litman, R.

    1978-01-01

    Neutron activation analysis has been used to monitor the loss of arsenic, as dimethylarsinic acid, (CH 3 ) 2 AsOOH, or as sodium arsenate (Na 2 HAsO 4 .7H 2 O), antimony (as potassium antimony, tartrate, KSbC 4 O 7 .1/2H 2 O) and bromine (as bromide ion) during lyophilization of acidified and neutral aqueous synthetic and environmental samples. Losses of Sb and As ranged from zero to 60%, while losses of bromine were constant (at 91%) in acidic solutions. The variable losses of As and Sb were due solely to the presence of and partial decomposition of the (CH 3 ) 2 AsOOH. Electrochemical oxidation of Br - to Br 2 is responsible for the high losses of bromine. In addition losses of mercury (as methylmercuric chloride) were 1O0% in both acidic and neutral aqueous synthetic samples during lyophilization. (author)

  7. Use of bromine as biocide in cooling waters (Preprint No. CA-19)

    Energy Technology Data Exchange (ETDEWEB)

    Sriraman, A K [Bhabha Atomic Research Centre, Bombay (India). Water Chemistry Div.

    1989-04-01

    In all fresh water circuits, the slime forming bacteria develop an insulating layer on the condenser surfaces. If these bacteria are not controlled, they induce bacterial promoted corrosion of the materials in contact with cooling water. Chlorination is effective against slime forming bacteria, fungi and algae. The algistatic nature of the chlorine is partly compensated by the use of other non-oxidisable biocides. Amongst the various alternative biocides such as bromine, methyl bis-isocyanate, sodium pentachlorophenate etc, bromine is the most simple biocide, which is being increasingly used in cooling water systems. In this context, the chemistry of bromination and its bactericidal properties is examined along with those of chlorination. (author). 7 refs., 3 tabs., 2 figs.

  8. Introduction to Physics and Chemistry of Combustion Explosion, Flame, Detonation

    CERN Document Server

    Liberman, Michael A

    2008-01-01

    Most of the material covered in this book deals with the fundamentals of chemistry and physics of key processes and fundamental mechanisms for various combustion and combustion related phenomena in gaseous combustible mixture. It provides the reader with basic knowledge of burning processes and mechanisms of reaction wave propagation. The combustion of a gas mixture (flame, explosion, detonation) is necessarily accompanied by motion of the gas. The process of combustion is therefore not only a chemical phenomenon but also one of gas dynamics. The material selection focuses on the gas phase and

  9. Conical quarl swirl stabilized non-premixed flames: flame and flow field interaction

    KAUST Repository

    Elbaz, Ayman M.; Roberts, William L.

    2017-01-01

    The flame-flow field interaction is studied in non-premixed methane swirl flames stabilized in quartz quarl via simultaneous measurements of the flow field using a stereo PIV and OH-PLIF at 5 KHz repetition rate. Under the same swirl intensity, two flames with different fuel jet velocity were investigated. The time-averaged flow field shows a unique flow pattern at the quarl exit, where two recirculation vortices are formed; a strong recirculation zone formed far from the quarl exit and a larger recirculation zone extending inside the quarl. However, the instantaneous images show that, the flow pattern near the quarl exit plays a vital role in the spatial location and structure of the reaction zone. In the low fuel jet velocity flame, a pair of vortical structures, located precisely at the corners of the quarl exit, cause the flame to roll up into the central region of low speed flow, where the flame sheet then tracks the axial velocity fluctuations. The vorticity field reveals a vortical structure surrounding the reaction zones, which reside on a layer of low compressive strain adjacent to that vortical structure. In the high fuel jet velocity flame, initially a laminar flame sheet resides at the inner shear layer of the main jet, along the interface between incoming fresh gas and high temperature recirculating gas. Further downstream, vortex breakdown alters the flame sheet path toward the central flame region. The lower reaction zones show good correlation to the regions of maximum vorticity and track the regions of low compressive strain associated with the inner shear layer of the jet flow. In both flames the reactions zones conform the passage of the large structure while remaining inside the low speed regions or at the inner shear layer.

  10. Conical quarl swirl stabilized non-premixed flames: flame and flow field interaction

    KAUST Repository

    Elbaz, Ayman M.

    2017-09-19

    The flame-flow field interaction is studied in non-premixed methane swirl flames stabilized in quartz quarl via simultaneous measurements of the flow field using a stereo PIV and OH-PLIF at 5 KHz repetition rate. Under the same swirl intensity, two flames with different fuel jet velocity were investigated. The time-averaged flow field shows a unique flow pattern at the quarl exit, where two recirculation vortices are formed; a strong recirculation zone formed far from the quarl exit and a larger recirculation zone extending inside the quarl. However, the instantaneous images show that, the flow pattern near the quarl exit plays a vital role in the spatial location and structure of the reaction zone. In the low fuel jet velocity flame, a pair of vortical structures, located precisely at the corners of the quarl exit, cause the flame to roll up into the central region of low speed flow, where the flame sheet then tracks the axial velocity fluctuations. The vorticity field reveals a vortical structure surrounding the reaction zones, which reside on a layer of low compressive strain adjacent to that vortical structure. In the high fuel jet velocity flame, initially a laminar flame sheet resides at the inner shear layer of the main jet, along the interface between incoming fresh gas and high temperature recirculating gas. Further downstream, vortex breakdown alters the flame sheet path toward the central flame region. The lower reaction zones show good correlation to the regions of maximum vorticity and track the regions of low compressive strain associated with the inner shear layer of the jet flow. In both flames the reactions zones conform the passage of the large structure while remaining inside the low speed regions or at the inner shear layer.

  11. Preparation of Flame Retardant Modified with Titanate for Asphalt Binder

    Directory of Open Access Journals (Sweden)

    Bo Li

    2014-01-01

    Full Text Available Improving the compatibility between flame retardant and asphalt is a difficult task due to the complex nature of the materials. This study explores a low dosage compound flame retardant and seeks to improve the compatibility between flame retardants and asphalt. An orthogonal experiment was designed taking magnesium hydroxide, ammonium polyphosphate, and melamine as factors. The oil absorption and activation index were tested to determine the effect of titanate on the flame retardant additive. The pavement performance test was conducted to evaluate the effect of the flame retardant additive. Oxygen index test was conducted to confirm the effect of flame retardant on flame ability of asphalt binder. The results of this study showed that the new composite flame retardant is more effective in improving the compatibility between flame retardant and asphalt and reducing the limiting oxygen index of asphalt binder tested in this study.

  12. Complete Reductive Dehalogenation of Brominated Biphenyls by Anaerobic Microorganisms in Sediment

    Science.gov (United States)

    Bedard, Donna L.; Van Dort, Heidi M.

    1998-01-01

    We sought to determine whether microorganisms from the polychlorinated biphenyl (PCB)-contaminated sediment in Woods Pond (Lenox, Mass.) could dehalogenate brominated biphenyls. The PCB dechlorination specificities for the microorganisms in this sediment have been well characterized. This allowed us to compare the dehalogenation specificities for brominated biphenyls and chlorinated biphenyls within a single sediment. Anaerobic sediment microcosms were incubated separately at 25°C with 16 different mono- to tetrabrominated biphenyls (350 μM) and disodium malate (10 mM). Samples were extracted and analyzed by gas chromatography with an electron capture detector and a mass spectrometer detector at various times for up to 54 weeks. All of the tested brominated biphenyls were dehalogenated. For most congeners, including 2,6-dibromobiphenyl (26-BB) and 24-25-BB, the dehalogenation began within 1 to 2 weeks. However, for 246-BB and 2-2-BB, debromination was first observed at 7 and 14 weeks, respectively. Most intermediate products did not persist, but when 2-2-BB was produced as a dehalogenation product, it persisted for at least 15 weeks before it was dehalogenated to 2-BB and then to biphenyl. The dehalogenation specificities for brominated and chlorinated biphenyls were similar: meta and para substituents were generally removed first, and ortho substituents were more recalcitrant. However, the brominated biphenyls were better dehalogenation substrates than the chlorinated biphenyls. All of the tested bromobiphenyls, including those with ortho and unflanked meta and para substituents, were ultimately dehalogenated to biphenyl, whereas their chlorinated counterparts either were not dehalogenation substrates or were only partially dehalogenated. Our data suggest that PCB-dechlorinating microorganisms may be able to dehalogenate brominated biphenyls and may exhibit a relaxed specificity for these substrates. PMID:16349530

  13. Bromination of Marine Dissolved Organic Matter following Full Scale Electrochemical Ballast Water Disinfection.

    Science.gov (United States)

    Gonsior, Michael; Mitchelmore, Carys; Heyes, Andrew; Harir, Mourad; Richardson, Susan D; Petty, William Tyler; Wright, David A; Schmitt-Kopplin, Philippe

    2015-08-04

    An extensively diverse array of brominated disinfection byproducts (DBPs) were generated following electrochemical disinfection of natural coastal/estuarine water, which is one of the main treatment methods currently under consideration for ballast water treatment. Ultra-high-resolution mass spectrometry revealed 462 distinct brominated DBPs at a relative abundance in the mass spectra of more than 1%. A brominated DBP with a relative abundance of almost 22% was identified as 2,2,4-tribromo-5-hydroxy-4-cyclopentene-1,3-dione, which is an analogue to several previously described 2,2,4-trihalo-5-hydroxy-4-cyclopentene-1,3-diones in drinking water. Several other brominated molecular formulas matched those of other known brominated DBPs, such as dibromomethane, which could be generated by decarboxylation of dibromoacetic acid during ionization, dibromophenol, dibromopropanoic acid, dibromobutanoic acid, bromohydroxybenzoic acid, bromophenylacetic acid, bromooxopentenoic acid, and dibromopentenedioic acid. Via comparison to previously described chlorine-containing analogues, bromophenylacetic acid, dibromooxopentenoic acid, and dibromopentenedioic acid were also identified. A novel compound at a 4% relative abundance was identified as tribromoethenesulfonate. This compound has not been previously described as a DBP, and its core structure of tribromoethene has been demonstrated to show toxicological implications. Here we show that electrochemical disinfection, suggested as a candidate for successful ballast water treatment, caused considerable production of some previously characterized DBPs in addition to novel brominated DBPs, although several hundred compounds remain structurally uncharacterized. Our results clearly demonstrate that electrochemical and potentially direct chlorination of ballast water in estuarine and marine systems should be approached with caution and the concentrations, fate, and toxicity of DBP need to be further characterized.

  14. Blowoff dynamics of bluff body stabilized turbulent premixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhuri, Swetaprovo; Kostka, Stanislav; Renfro, Michael W.; Cetegen, Baki M. [Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, U-3139, Storrs, CT 06269 (United States)

    2010-04-15

    This article concerns the flame dynamics of a bluff body stabilized turbulent premixed flame as it approaches lean blowoff. Time resolved chemiluminescence imaging along with simultaneous particle image velocimetry and OH planar laser-induced fluorescence were utilized in an axisymmetric bluff body stabilized, propane-air flame to determine the sequence of events leading to blowoff and provide a quantitative analysis of the experimental results. It was found that as lean blowoff is approached by reduction of equivalence ratio, flame speed decreases and the flame shape progressively changes from a conical to a columnar shape. For a stably burning conical flame away from blowoff, the flame front envelopes the shear layer vortices. Near blowoff, the columnar flame front and shear layer vortices overlap to induce high local stretch rates that exceed the extinction stretch rates instantaneously and in the mean, resulting in local flame extinction along the shear layers. Following shear layer extinction, fresh reactants can pass through the shear layers to react within the recirculation zone with all other parts of the flame extinguished. This flame kernel within the recirculation zone may survive for a few milliseconds and can reignite the shear layers such that the entire flame is reestablished for a short period. This extinction and reignition event can happen several times before final blowoff which occurs when the flame kernel fails to reignite the shear layers and ultimately leads to total flame extinguishment. (author)

  15. Flame Structure of Vitiated Fuel-Rich Inverse Diffusion Flames in a Cross-Flow (Postprint)

    Science.gov (United States)

    2011-12-01

    downstream of the slot. The flame length increases as the blowing ratio increases as a result of the greater mass of air which reacts. Ignition of...attributed to the greater penetration of the jet into the cross-stream. It is noted that the flame lengths are similar for the different blowing ratios

  16. Laminar Flame Speeds of Gasoline Surrogates Measured with the Flat Flame Method

    KAUST Repository

    Liao, Y.-H.; Roberts, William L.

    2016-01-01

    © 2016 American Chemical Society. The adiabatic, laminar flame speeds of gasoline surrogates at atmospheric pressure over a range of equivalence ratios of = 0.8-1.3 and unburned gas temperatures of 298-400 K are measured with the flat flame method

  17. On the dynamics of flame edges in diffusion-flame/vortex interactions

    Energy Technology Data Exchange (ETDEWEB)

    Hermanns, Miguel; Linan, Amable [Departamento de Motopropulsion y Termofluidodinamica, Universidad Politecnica de Madrid, Pza. Cardenal Cisneros 3, 28040 Madrid (Spain); Vera, Marcos [Area de Mecanica de Fluidos, Universidad Carlos III de Madrid, 28911 Leganes (Spain)

    2007-04-15

    We analyze the local flame extinction and reignition of a counterflow diffusion flame perturbed by a laminar vortex ring. Local flame extinction leads to the appearance of flame edges separating the burning and extinguished regions of the distorted mixing layer. The dynamics of these edges is modeled based on previous numerical results, with heat release effects fully taken into account, which provide the propagation velocity of triple and edge flames in terms of the upstream unperturbed value of the scalar dissipation. The temporal evolution of the mixing layer is determined using the classical mixture fraction approach, with both unsteady and curvature effects taken into account. Although variable density effects play an important role in exothermic reacting mixing layers, in this paper the description of the mixing layer is carried out using the constant density approximation, leading to a simplified analytical description of the flow field. The mathematical model reveals the relevant nondimensional parameters governing diffusion-flame/vortex interactions and provides the parameter range for the more relevant regime of local flame extinction followed by reignition via flame edges. Despite the simplicity of the model, the results show very good agreement with previously published experimental results. (author)

  18. Turbulence-flame interactions in DNS of a laboratory high Karlovitz premixed turbulent jet flame

    Science.gov (United States)

    Wang, Haiou; Hawkes, Evatt R.; Chen, Jacqueline H.

    2016-09-01

    In the present work, direct numerical simulation (DNS) of a laboratory premixed turbulent jet flame was performed to study turbulence-flame interactions. The turbulent flame features moderate Reynolds number and high Karlovitz number (Ka). The orientations of the flame normal vector n, the vorticity vector ω and the principal strain rate eigenvectors ei are examined. The in-plane and out-of-plane angles are introduced to quantify the vector orientations, which also measure the flame geometry and the vortical structures. A general observation is that the distributions of these angles are more isotropic downstream as the flame and the flow become more developed. The out-of-plane angle of the flame normal vector, β, is a key parameter in developing the correction of 2D measurements to estimate the corresponding 3D quantities. The DNS results show that the correction factor is unity at the inlet and approaches its theoretical value of an isotropic distribution downstream. The alignment characteristics of n, ω and ei, which reflect the interactions of turbulence and flame, are also studied. Similar to a passive scalar gradient in non-reacting flows, the flame normal has a tendency to align with the most compressive strain rate, e3, in the flame, indicating that turbulence contributes to the production of scalar gradient. The vorticity dynamics are examined via the vortex stretching term, which was found to be the predominant source of vorticity generation balanced by dissipation, in the enstrophy transport equation. It is found that although the vorticity preferentially aligns with the intermediate strain rate, e2, the contribution of the most extensive strain rate, e1, to vortex stretching is comparable with that of the intermediate strain rate, e2. This is because the eigenvalue of the most extensive strain rate, λ1, is always large and positive. It is confirmed that the vorticity vector is preferentially positioned along the flame tangential plane, contributing

  19. Analytical capabilities of high performance liquid chromatography - Atmospheric pressure photoionization - Orbitrap mass spectrometry (HPLC-APPI-Orbitrap-MS) for the trace determination of novel and emerging flame retardants in fish.

    Science.gov (United States)

    Zacs, D; Bartkevics, V

    2015-10-22

    A new analytical method was established and validated for the analysis of 27 brominated flame retardants (BFRs), including so called "emerging" and "novel" BFRs (EBFRs and NBFRs) in fish samples. High performance liquid chromatography (HPLC) coupled to Orbitrap mass spectrometry (Orbitrap-MS) employing atmospheric pressure photoionization (APPI) interface operated in negative mode was used for the identification/quantitation of contaminants. HPLC-Orbitrap-MS analysis provided a fast separation of selected analytes within 14 min, thus demonstrating a high throughput processing of samples. The developed methodology was tested by intralaboratory validation in terms of recovery, repeatability, linear calibration ranges, instrumental and method limits of quantitation (i-LOQ and m-LOQ), and where possible, trueness was verified by analysis of certified reference materials (CRMs). Recoveries of analytes were between 80 and 119%, while the repeatability in terms of relative standard deviations (RSDs) was in the range from 1.2 to 15.5%. The measured values for both analyzed CRMs agreed with the provided consensus values, revealing the recovery of reference concentrations in 72-119% range. The elaborated method met the sensitivity criterion according to Commission Recommendation 2014/118/EU on monitoring of BFRs in food products for majority of the compounds. The concentrations of polybrominated diphenyl ethers (PBDEs) in real samples determined by HPLC-APPI-Orbitrap-MS method and validated gas chromatography-high-resolution mass spectrometry (GC-HRMS) method were found to be in a good agreement. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Flame Quenching Dynamics of High Velocity Flames in Rectangular Cross-section Channels

    KAUST Repository

    Mahuthannan, Ariff Magdoom; Lacoste, Deanna; Damazo, Jason; Kwon, Eddie; Roberts, William L.

    2017-01-01

    Understanding flame quenching for different conditions is necessary to develop safety devices like flame arrestors. In practical applications, the speed of a deflagration in the lab-fixed reference frame will be a strong function of the geometry through which the deflagration propagates. This study reports on the effect of the flame speed, at the entrance of a quenching section, on the quenching distance. A 2D rectangular channel joining two main spherical vessels is considered for studying this effect. Two different velocity regimes are investigated and referred to as configurations A, and B. For configuration A, the velocity of the flame is 20 m/s, while it is about 100 m/s for configuration B. Methane-air stoichiometric mixtures at 1 bar and 298 K are used. Simultaneous dynamic pressure measurements along with schlieren imaging are used to analyze the quenching of the flame. Risk assessment of re-ignition is also reported and analyzed.

  1. Flame Quenching Dynamics of High Velocity Flames in Rectangular Cross-section Channels

    KAUST Repository

    Mahuthannan, Ariff Magdoom

    2017-01-05

    Understanding flame quenching for different conditions is necessary to develop safety devices like flame arrestors. In practical applications, the speed of a deflagration in the lab-fixed reference frame will be a strong function of the geometry through which the deflagration propagates. This study reports on the effect of the flame speed, at the entrance of a quenching section, on the quenching distance. A 2D rectangular channel joining two main spherical vessels is considered for studying this effect. Two different velocity regimes are investigated and referred to as configurations A, and B. For configuration A, the velocity of the flame is 20 m/s, while it is about 100 m/s for configuration B. Methane-air stoichiometric mixtures at 1 bar and 298 K are used. Simultaneous dynamic pressure measurements along with schlieren imaging are used to analyze the quenching of the flame. Risk assessment of re-ignition is also reported and analyzed.

  2. Radiation Effects on the Thermodiffusive Instability of Premixed Flames on a Cylindrical Porous Flame Holder

    Science.gov (United States)

    Du, Minglong; Yang, Lijun

    2017-10-01

    A linear analysis method was used to investigate the mechanics of radiation heat loss and mass transfer in the porous wall of premixed annular flames and their effect on thermodiffusive instability. The dispersion relation between the disturbance wave growth rate and wavenumber was calculated numerically. Results showed that radiation heat loss elevated the annular flame slightly away from the porous wall. In the annular flame with small Lewis numbers, radiation heat loss changed the thermodiffusive instability from a pulsating to a cellular state, while for the large Lewis numbers, only the pulsating instability was represented. Increasing radiation heat loss and the radius of the porous wall enhanced the instability of the annular flames. Heat losses decreased with the continued increase in thickness of the porous wall and the decrease in porosity. Annular flames with long-wave mode along the angular direction were more unstable than the shortwave mode.

  3. Enhancement of flame development by microwave-assisted spark ignition in constant volume combustion chamber

    KAUST Repository

    Wolk, Benjamin; DeFilippo, Anthony; Chen, Jyh-Yuan; Dibble, Robert; Nishiyama, Atsushi; Ikeda, Yuji

    2013-01-01

    -thermal chemical kinetic enhancement from energy deposition to free electrons in the flame front and (2) induced flame wrinkling from excitation of flame (plasma) instability. The enhancement of flame development by microwaves diminishes as the initial pressure

  4. Soot reduction under DC electric fields in counterflow non-premixed laminar ethylene flames

    KAUST Repository

    Park, Daegeun

    2014-04-23

    The effects of DC electric fields on non-premixed ethylene flames in a counterflow burner were studied experimentally with a focus on the reduction of soot particles. The experiment was conducted by connecting a high voltage terminal and a ground terminal to a lower (fuel) and upper (oxidizer) nozzle, respectively. We applied direct current (DC) potentials in a range of -5 kV < Vdc < 5 kV. Uniform electric fields were then generated in the gap between the two nozzles. The experimental conditions were selected to cover both soot formation (SF) and soot formation oxidation (SFO) flames. The flames subjected to the negative electric fields moved toward the fuel nozzle because of an ionic wind due to the Lorentz force acting on the positive ions in the flames. In addition, the yellow luminosity significantly decreased, indicating changes in the sooting characteristics. To analyze the sooting characteristics under the electric fields, planar laser induced incandescence (PLII) and fluorescence (PLIF) techniques were used to visualize the soot, polycyclic aromatic hydrocarbons (PAHs), and OH radicals. The sooting limits in terms of the fuel and oxygen mole fractions were measured. No substantial soot formation due to the effects of the DC electric fields for the tested range of voltages and reactant mole fractions could be identified. The detailed flame behaviors and sooting characteristics under the DC electric fields are discussed. Copyright © Taylor & Francis Group, LLC.

  5. NO emission characteristics in counterflow diffusion flame of blended fuel of H2/CO2/Ar

    International Nuclear Information System (INIS)

    Jeong Park; Kyunghwan Lee; Keeman Lee

    2002-01-01

    Flame structure and NO emission characteristics in counterflow diffusion flame of blended fuel of H 2 /CO 2 /Ar have been numerically simulated with detailed chemistry. The combination of H 2 , CO 2 and Ar as fuel is selected to clearly display the contribution of hydrocarbon products to flame structure and NO emission characteristics due to the breakdown of CO 2 . A radiative heat loss term is involved to correctly describe the flame dynamics especially at low strain rates. The detailed chemistry adopts the reaction mechanism of GRI 2.11, which consists of 49 species and 279 elementary reactions. All mechanisms including thermal, NO 2 , N 2 O and Fenimore are taken into account to separately evaluate the effects of CO 2 addition on NO emission characteristics. The increase of added CO 2 quantity causes flame temperature to fall since at high strain rates a diluent effect is prevailing and at low strain rates the breakdown of CO 2 produces relatively populous hydrocarbon products and thus the existence of hydrocarbon products inhibits chain branching. It is also found that the contribution of NO production by N 2 O and NO 2 mechanisms are negligible and that thermal mechanism is concentrated on only the reaction zone. As strain rate and CO 2 quantity increase, NO production is remarkably augmented. (Author)

  6. An experimental and kinetic investigation of premixed furan/oxygen/argon flames.

    Science.gov (United States)

    Tian, Zhenyu; Yuan, Tao; Fournet, Rene; Glaude, Pierre-Alexandre; Sirjean, Baptiste; Battin-Leclerc, Frédérique; Zhang, Kuiwen; Qi, Fei

    2011-04-01

    The detailed chemical structures of three low-pressure (35 Torr) premixed laminar furan/oxygen/argon flames with equivalence ratios of 1.4, 1.8 and 2.2 have been investigated by using tunable synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam mass spectrometry. About 40 combustion species including hydrocarbons and oxygenated intermediates have been identified by measurements of photoionization efficiency spectra. Mole fraction profiles of the flame species including reactants, intermediates and products have been determined by scanning burner position with some selected photon energies near ionization thresholds. Flame temperatures have been measured by a Pt-6%Rh/Pt-30%Rh thermocouple. A new mechanism involving 206 species and 1368 reactions has been proposed whose predictions are in reasonable agreement with measured species profiles for the three investigated flames. Rate-of-production and sensitivity analyses have been performed to track the key reaction paths governing furan consumption for different equivalence ratios. Both experimental and modeling results indicate that few aromatics could be formed in these flames. Furthermore, the current model has been validated against previous pyrolysis results of the literature obtained behind shock waves and the agreement is reasonable as well.

  7. Gravity Effects Observed In Partially Premixed Flames

    Science.gov (United States)

    Puri, Ishwar K.; Aggarwal, Suresh K.; Lock, Andrew J.; Gauguly, Ranjan; Hegde, Uday

    2003-01-01

    Partially premixed flames (PPFs) contain a rich premixed fuel air mixture in a pocket or stream, and, for complete combustion to occur, they require the transport of oxidizer from an appropriately oxidizer-rich (or fuel-lean) mixture that is present in another pocket or stream. Partial oxidation reactions occur in fuel-rich portions of the mixture and any remaining unburned fuel and/or intermediate species are consumed in the oxidizer-rich portions. Partial premixing, therefore, represents that condition when the equivalence ratio (phi) in one portion of the flowfield is greater than unity, and in another section its value is less than unity. In general, for combustion to occur efficiently, the global equivalence ratio is in the range fuel-lean to stoichiometric. These flames can be established by design by placing a fuel-rich mixture in contact with a fuel-lean mixture, but they also occur otherwise in many practical systems, which include nonpremixed lifted flames, turbulent nonpremixed combustion, spray flames, and unwanted fires. Other practical applications of PPFs are reported elsewhere. Although extensive experimental studies have been conducted on premixed and nonpremixed flames under microgravity, there is a absence of previous experimental work on burner stabilized PPFs in this regard. Previous numerical studies by our group employing a detailed numerical model showed gravity effects to be significant on the PPF structure. We report on the results of microgravity experiments conducted on two-dimensional (established on a Wolfhard-Parker slot burner) and axisymmetric flames (on a coannular burner) that were investigated in a self-contained multipurpose rig. Thermocouple and radiometer data were also used to characterize the thermal transport in the flame.

  8. Ultra-high-pressure liquid chromatography tandem mass spectrometry method for the determination of 9 organophosphate flame retardants in water samples

    NARCIS (Netherlands)

    Lorenzo, M.; Campo, J.; Picó, Y.

    2016-01-01

    Few methods are available for comprehensive organophosphate flame retardants (PFRs) detection in water and wastewater. Gas chromatography has been employed previously, but this approach is less selective, not amenable for use with deuterated standards and can suffer unfavorable fragmentation.

  9. Concentrations in air of organobromine, organochlorine and organophosphate flame retardants in Toronto, Canada

    Science.gov (United States)

    Shoeib, Mahiba; Ahrens, Lutz; Jantunen, Liisa; Harner, Tom

    2014-12-01

    Concentrations of organobromine (BFRs), organochlorine (CFRs) and organophosphate esters flame retardants and plasticizers (PFRs) in air were monitored for over one year at an urban site in Toronto, Canada during 2010-2011. The mean value for polybrominated diphenyl ethers (BDEs) (gas + particle phase) was 38 pg/m3 with BDE-47 and BDE-99 as the dominant congeners. The mean concentrations in air for ∑non-BDE (BFRs and CFRs), was 9.6 pg/m3 - about four times lower than the BDEs. The brominated FRs: TBP-AE, BTBPE, EH-TBB, BEH-TEBP and the chlorinated syn- and anti-DP were detected frequently, ranging from 87% to 96%. Highest concentrations in air among all flame retardant classes were observed for the Σ-PFRs. The yearly mean concentration in air for ΣPFRs was 2643 pg/m3 with detection frequency higher than 80%. Except for TBP-AE and b- DBE-DBCH, non-BDEs (BFRs, CFRs and PFRs) were mainly associated with the particle phase. BDE concentrations in air were positively correlated with temperature indicating that volatilization from local sources was an important factor controlling levels in air. This correlation did not hold for most BFRs, CFRs and PFRs which were mainly on particles. For these compounds, air concentrations in Toronto are likely related to emissions from point sources and advective inputs. This study highlights the importance of urban air monitoring for FRs. Urban air can be considered a sentinel for detecting changes in the use and application of FRs in commercial products.

  10. Sooting turbulent jet flame: characterization and quantitative soot measurements

    Science.gov (United States)

    Köhler, M.; Geigle, K. P.; Meier, W.; Crosland, B. M.; Thomson, K. A.; Smallwood, G. J.

    2011-08-01

    Computational fluid dynamics (CFD) modelers require high-quality experimental data sets for validation of their numerical tools. Preferred features for numerical simulations of a sooting, turbulent test case flame are simplicity (no pilot flame), well-defined boundary conditions, and sufficient soot production. This paper proposes a non-premixed C2H4/air turbulent jet flame to fill this role and presents an extensive database for soot model validation. The sooting turbulent jet flame has a total visible flame length of approximately 400 mm and a fuel-jet Reynolds number of 10,000. The flame has a measured lift-off height of 26 mm which acts as a sensitive marker for CFD model validation, while this novel compiled experimental database of soot properties, temperature and velocity maps are useful for the validation of kinetic soot models and numerical flame simulations. Due to the relatively simple burner design which produces a flame with sufficient soot concentration while meeting modelers' needs with respect to boundary conditions and flame specifications as well as the present lack of a sooting "standard flame", this flame is suggested as a new reference turbulent sooting flame. The flame characterization presented here involved a variety of optical diagnostics including quantitative 2D laser-induced incandescence (2D-LII), shifted-vibrational coherent anti-Stokes Raman spectroscopy (SV-CARS), and particle image velocimetry (PIV). Producing an accurate and comprehensive characterization of a transient sooting flame was challenging and required optimization of these diagnostics. In this respect, we present the first simultaneous, instantaneous PIV, and LII measurements in a heavily sooting flame environment. Simultaneous soot and flow field measurements can provide new insights into the interaction between a turbulent vortex and flame chemistry, especially since soot structures in turbulent flames are known to be small and often treated in a statistical manner.

  11. Control of confined nonpremixed flames using a microjet

    International Nuclear Information System (INIS)

    Sinha, Ashok; Ganguly, Ranjan; Puri, Ishwar K.

    2005-01-01

    Industrial burners, such as those used in materials processing furnaces, require precise control over the flame length, width, overall shape and other physical flame attributes. The mechanism used to control the flame topology should be relatively simple, safe, and devoid of an emissions penalty. We have explored the feasibility of hydrodynamic control of confined nonpremixed flames by injecting air through a high-momentum microjet. An innovative strategy for the control of flame shape and luminosity is demonstrated based on a high-momentum coaxial microjet injected along the center of a confined nonpremixed flame burning in a coflowing oxidizer stream. The introduction of the microjet shortens a nonpremixed flame and reduces the amplitude of the buoyancy-induced flickering. For a microjet-assisted flame, the flame length is more sensitive to the fuel flowrate than for laminar or turbulent nonpremixed flames. This provides greater flexibility for the dynamic control of their flame lengths. Measurements of NO x and CO emissions show that the method is robust. Effective flame control without an emissions penalty is possible over a large range of microjet velocities that significantly alter the flame shape. Since the influence of the microjet is primarily of a hydrodynamic nature, inert microjet fluids like recirculated exhaust gas can also be used in practical devices

  12. Control of confined nonpremixed flames using a microjet

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, A.; Puri, I.K. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Engineering Science and Mechanics; Ganguly, R. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Engineering Science and Mechanics; Jadavpur Univ., Calcutta (India). Dept. of Power Engineering

    2005-06-01

    Industrial burners, such as those used in materials processing furnaces, require precise control over the flame length, width, overall shape and other physical flame attributes. The mechanism used to control the flame topology should be relatively simple, safe, and devoid of an emissions penalty. We have explored the feasibility of hydrodynamic control of confined nonpremixed flames by injecting air through a high-momentum microjet. An innovative strategy for the control of flame shape and luminosity is demonstrated based on a high-momentum coaxial microjet injected along the center of a confined nonpremixed flame burning in a coflowing oxidizer stream. The introduction of the microjet shortens a nonpremixed flame and reduces the amplitude of the buoyancy-induced flickering. For a microjet-assisted flame, the flame length is more sensitive to the fuel flowrate than for laminar or turbulent nonpremixed flames. This provides greater flexibility for the dynamic control of their flame lengths. Measurements of NO{sub x} and CO emissions show that the method is robust. Effective flame control without an emissions penalty is possible over a large range of microjet velocities that significantly alter the flame shape. Since the influence of the microjet is primarily of a hydrodynamic nature, inert microjet fluids like recirculated exhaust gas can also be used in practical devices. (Author)

  13. Characteristics of diffusion flames with accelerated motion

    Directory of Open Access Journals (Sweden)

    Lou Bo

    2016-01-01

    Full Text Available The aim of this work is to present an experiment to study the characteristics of a laminar diffusion flame under acceleration. A Bunsen burner (nozzle diameter 8 mm, using liquefied petroleum gas as its fuel, was ignited under acceleration. The temperature field and the diffusion flame angle of inclination were visualised with the assistance of the visual display technology incorporated in MATLAB™. Results show that the 2-d temperature field under different accelerations matched the variation in average temperatures: they both experience three variations at different time and velocity stages. The greater acceleration has a faster change in average temperature with time, due to the accumulation of combustion heat: the smaller acceleration has a higher average temperature at the same speed. No matter what acceleration was used, in time, the flame angle of inclination increased, but the growth rate decreased until an angle of 90°: this could be explained by analysis of the force distribution within the flame. It is also found that, initially, the growth rate of angle with velocity under the greater acceleration was always smaller than that at lower accelerations; it was also different in flames with uniform velocity fire conditions.

  14. Chaotic radiation/turbulence interactions in flames

    Energy Technology Data Exchange (ETDEWEB)

    Menguec, M.P.; McDonough, J.M.

    1998-11-01

    In this paper, the authors present a review of their recent efforts to model chaotic radiation-turbulence interactions in flames. The main focus is to characterize soot volume fraction fluctuations in turbulent diffusion flames, as they strongly contribute to these interaction. The approach is based on the hypothesis that the fluctuations of properties in turbulent flames are deterministic in nature, rather than random. The authors first discuss the theoretical details and then they briefly outline the experiments conducted to measure the scattered light signals from fluctuating soot particles along the axis of an ethylene-air diffusion flame. They compare the power spectra and time series obtained from experiments against the ad-hoc and rigorous models derived using a series of logistic maps. These logistic maps can be used in simulation of the fluctuations in these type of flames, without extensive computational effort or sacrifice of physical detail. Availability of accurate models of these kinds allows investigation of radiation-turbulence interactions at a more fundamental level than it was previously possible.

  15. Flame Retardant Effect of Nano Fillers on Polydimethylsiloxane Composites.

    Science.gov (United States)

    Jagdale, Pravin; Salimpour, Samera; Islam, Md Hujjatul; Cuttica, Fabio; Hernandez, Francisco C Robles; Tagliaferro, Alberto; Frache, Alberto

    2018-02-01

    Polydimethylsiloxane has exceptional fire retardancy characteristics, which make it a popular polymer in flame retardancy applications. Flame retardancy of polydimethylsiloxane with different nano fillers was studied. Polydimethylsiloxane composite fire property varies because of the shape, size, density, and chemical nature of nano fillers. In house made carbon and bismuth oxide nano fillers were used in polydimethylsiloxane composite. Carbon from biochar (carbonised bamboo) and a carbon by-product (carbon soot) were selected. For comparative study of nano fillers, standard commercial multiwall carbon nano tubes (functionalised, graphitised and pristine) as nano fillers were selected. Nano fillers in polydimethylsiloxane positively affects their fire retardant properties such as total smoke release, peak heat release rate, and time to ignition. Charring and surface ceramization are the main reasons for such improvement. Nano fillers in polydimethylsiloxane may affect the thermal mobility of polymer chains, which can directly affect the time to ignition. The study concludes that the addition of pristine multiwall carbon nano tubes and bismuth oxide nano particles as filler in polydimethylsiloxane composite improves the fire retardant property.

  16. Unintentional production of persistent chlorinated and brominated organic pollutants during iron ore sintering processes.

    Science.gov (United States)

    Li, Sumei; Liu, Guorui; Zheng, Minghui; Liu, Wenbin; Li, Jinhui; Wang, Mei; Li, Changliang; Chen, Yuan

    2017-06-05

    Iron ore sintering (SNT) processes are major sources of unintentionally produced chlorinated persistent organic pollutants (POPs), including polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs). However, few studies of emissions of brominated POPs, such as polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs) and polybrominated diphenyl ethers (PBDEs), during SNT have been performed. Stack gas and fly ash samples from six typical SNT plants in China were collected and analyzed to determine the concentrations and profiles of PCDD/Fs, PCBs, PCNs, PBDD/Fs, and PBDEs, as well as any correlations among these compounds. The PCDD/F, PCB, PCN, PBDD/F, and PBDE emission factors were 2.47, 0.61, 552, 0.32, and 107μgt -1 , respectively (109, 4.07, 10.4, 4.41 and 0.02ng toxic equivalents t -1 , respectively). PCBs were the most abundant compounds by mass, while PCNs were the next most abundant, contributing 51% and 42% to the total POP concentration, respectively. However, PCDD/Fs were the dominant contributors to the chlorinated and brominated POP toxic equivalent concentrations, contributing 89% to the total toxic equivalent concentration. The PCDD/F and other chlorinated and brominated POP concentrations were positively correlated, indicating that chlorinated and brominated POP emissions could be synergistically decreased using the best available technologies/best environmental practices already developed for PCDD/Fs. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Interaction of chelate cyclopentadienyl compounds of zirconium and hafnium with bromine

    International Nuclear Information System (INIS)

    Brajnina, Eh.M.; Minacheva, M.Kh.

    1975-01-01

    Interaction of bromine with Zr and Hf dibenzoylmethane (DBM) compounds of following type: (DBM) 4 M, CpM(DBM) 3 and Cp 2 M(DBM) 2 leads to the formation of (DBM) 2 MBr 2 , (DBM) 3 MBr and CpZr(DBM) 2 Br in the rations which depend on the conditions of the reaction (Cp=C 5 H 5 )

  18. XAS AND XPS CHARACTERIZATION OF MERCURY BINDING ON BROMINATED ACTIVATED CARBON

    Science.gov (United States)

    Brominated powdered activated carbon sorbents have been shown to e quite effective for mercury capture when injected into the flue gas duct at coal-fired power plants and are especially useful when buring Western low-chlorine subbituminous coals. X-ray absorption spectroscopy (X...

  19. Preparation of radioactive labelled compounds. Pt. 2. 82Br labelled organic bromine compounds by isotopic exchange

    International Nuclear Information System (INIS)

    Otto, R.

    1988-05-01

    Studies on isotopic exchange between organic bromine compounds and 82 Br labelled dioxane dibromide in the presence of AlCl 3 are described. The results obtained enable to develop a simple and quick preparation method for the labelling with 82 Br [fr

  20. Bromine content in some seaweeds of Goa (Central West Coast of India)

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.; Mittal, P.K.; Kamat, S.Y.; Solimabi; Reddy, C.V.G.

    in chloroform at 400 and 650 nm. The bromine content, on a dry dry weight basis, varied from 0.024 to 0.024% for the green algae, from 0.020 to 0.400% for the algae, and from 0.015 to 0.054% for the brown algae. Only two species @iChondria armata@@ and @i...

  1. Relationship among iodine, bromine and chlorine concentrations in cow's milk in Japan

    International Nuclear Information System (INIS)

    Ohno, Shigeru; Itoh, Takashi; Morishima, Hiroshige; Honda, Yoshihide.

    1989-01-01

    In order to know the relationship among some elements in biological materials, iodine, bromine and chlorine concentrations in cow's milk samples in Japan were determined by the thermal neutron activation analysis using a low power research reactor and a Van de Graaff accelerator. The iodine contents in cow's milk samples ranged from 0.041 to 0.316 ppm with an average of 0.096 ppm. The bromine and chlorine in these samples ranged from 2.3 to 11.1 ppm and from 475 to 1650 ppm, respectively. The average concentration of the bromine was calculated to be 5.6 ppm and that of the chlorine was 853 ppm. The relationship among iodine, bromine and chlorine concentrations in cow's milk samples in Japan was studied with a regression analysis. It was suggested that the correlation has a power function as follows; Y = K(Z) -A where, Y is elemental concentration in ppm, Z is atomic number of element, A (=7.4) is exponent and K (=14.7) is a constant. (author)

  2. Ullmann-type coupling of brominated tetrathienoanthracene on copper and silver

    Czech Academy of Sciences Publication Activity Database

    Gutzler, R.; Cardenas, L.; Lipton-Duffin, J.; El Garah, M.; Dinca, L.E.; Szakacs, C.E.; Fu, Ch.; Gallagher, M.; Vondráček, Martin; Rybachuk, M.; Perepichka, D.F.; Rosei, F.

    2014-01-01

    Roč. 6, č. 5 (2014), 2660-2668 ISSN 2040-3364 R&D Projects: GA MŠk(CZ) LM2011029 Institutional support: RVO:68378271 Keywords : Ullmann reaction * brominated tetrathienoanthracene * high resolution photoemission * STM Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.394, year: 2014

  3. Preliminary study on the occurrence of brominated organic compounds in Dutch marine organisms

    NARCIS (Netherlands)

    Kotterman, M.J.J.; Veen, van der I.; Hesselingen, van J.M.; Leonards, P.E.G.; Osinga, R.; Boer, de J.

    2003-01-01

    The extracts of three marine organisms; the ascidian Ciona intestinalis, the brown seaweed Sargassum muticum and the sponge Halichondria panicea, all elicited a number of brominated compounds, some of which were tentatively identified. Tribromophenol was observed in all species. This compound, also

  4. Kinetics of aerobic cometabolic biodegradation of chlorinated and brominated aliphatic hydrocarbons: A review.

    Science.gov (United States)

    Jesus, João; Frascari, Dario; Pozdniakova, Tatiana; Danko, Anthony S

    2016-05-15

    This review analyses kinetic studies of aerobic cometabolism (AC) of halogenated aliphatic hydrocarbons (HAHs) from 2001-2015 in order to (i) compare the different kinetic models proposed, (ii) analyse the estimated model parameters with a focus on novel HAHs and the identification of general trends, and (iii) identify further research needs. The results of this analysis show that aerobic cometabolism can degrade a wide range of HAHs, including HAHs that were not previously tested such as chlorinated propanes, highly chlorinated ethanes and brominated methanes and ethanes. The degree of chlorine mineralization was very high for the chlorinated HAHs. Bromine mineralization was not determined for studies with brominated aliphatics. The examined research period led to the identification of novel growth substrates of potentially high interest. Decreasing performance of aerobic cometabolism were found with increasing chlorination, indicating the high potential of aerobic cometabolism in the presence of medium- and low-halogenated HAHs. Further research is needed for the AC of brominated aliphatic hydrocarbons, the potential for biofilm aerobic cometabolism processes, HAH-HAH mutual inhibition and the identification of the enzymes responsible for each aerobic cometabolism process. Lastly, some indications for a possible standardization of future kinetic studies of HAH aerobic cometabolism are provided. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Biodegradation of brominated aromatics by cultures and laccase of Trametes versicolor

    Czech Academy of Sciences Publication Activity Database

    Uhnáková, Bronislava; Petříčková, Alena; Biedermann, David; Homolka, Ladislav; Vejvoda, Vojtěch; Bednář, P.; Papoušková, B.; Šulc, Miroslav; Martínková, Ludmila

    2009-01-01

    Roč. 76, č. 6 (2009), s. 826-832 ISSN 0045-6535 R&D Projects: GA MŠk 2B06151 Institutional research plan: CEZ:AV0Z50200510 Keywords : Brominated phenols * Tetrabromobisphenol A * Laccase Subject RIV: CE - Biochemistry Impact factor: 3.253, year: 2009

  6. The distribution of lignin in white birch wood as determined by bromination with TEM-EDXA

    International Nuclear Information System (INIS)

    Saka, S.; Goring, D.A.I.

    1988-01-01

    Ultraviolet absorbance and bromine uptake were measured on various morphological regions of birch wood. To facilitate precise comparison, observations were made on identical locations in successive cross sections. From the data, the concentration of lignin and the ratio of the guaiacyl to syringyl residues were determined. The results obtained were then compared with the previous findings from the use of UV microscopy alone

  7. Laboratory Studies of Stratospheric Bromine Chemistry: Kinetics of the Reactions of Bromine Monoxide with Nitrogen Dioxide and Atomic Oxygen.

    Science.gov (United States)

    Thorn, Robert Peyton, Jr.

    interferences from production of vibrationally or electronically excited O_2 are discussed. The effect of the faster reaction rate coefficients that are reported for the rm BrO + NO_2 + M and BrO + O(^3P) reactions upon bromine partitioning and ozone depletion in the stratosphere is discussed.

  8. Early structure of LPG partially premixed conically stabilized flames

    KAUST Repository

    Elbaz, Ayman M.

    2013-01-01

    This paper presents experimental investigation of LPG partially premixed turbulent flames stabilized within a conical nozzle burner under constant degree of partial premixing. The stability limits and mean flame structure are presented based

  9. Effect of hydrogen addition on autoignited methane lifted flames

    KAUST Repository

    Choin, Byung Chul; Chung, Suk-Ho

    2012-01-01

    Autoignited lifted flames in laminar jets with hydrogen-enriched methane fuels have been investigated experimentally in heated coflow air. The results showed that the autoignited lifted flame of the methane/hydrogen mixture, which had an initial

  10. Ion measurements in premixed methane-oxygen flames

    KAUST Repository

    Alquaity, Awad; Hourani, Nadim; Chahine, May; Selim, Hatem; Sarathy, Mani; Farooq, Aamir

    2014-01-01

    Mass Spectrometer (MBMS) is utilized to measure ion concentration profiles in premixed methane-oxygen-argon burner-stabilized flames. Lean, stoichiometric and rich flames at atmospheric pressure are used to study the dependence of ion chemistry

  11. Visualization of ionic wind in laminar jet flames

    KAUST Repository

    Park, Daegeun

    2017-07-03

    Electric field, when it is applied to hydrocarbon flames, generates ionic wind due to the electric body force on charge carrying species. Ionic wind has been shown to influence soot emission, propagation speed, and stability of flames; however, a detailed behavior of ionic wind and its effects on flames is still not clear. Here, we investigated the dynamic behaviors of flames and ionic wind in the presence of direct current (DC) and alternating current (AC) electric fields in nonpremixed and premixed jet flames with a jet nozzle placed between two parallel electrodes. We observed a skewed flame toward a lower potential electrode with DC and lower frequency AC (e.g., 10Hz) and a steady flame with higher frequencies AC (1000Hz), while we found that the ionic wind blew toward both the anode and cathode regardless of flame type (nonpremixed or premixed) or the source of the electric field (DC and AC).

  12. Beam steering effects in turbulent high pressure flames

    Energy Technology Data Exchange (ETDEWEB)

    Hemmerling, B; Kaeppeli, B [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    The propagation of a laser beam through a flame is influenced by variations of the optical density. Especially in turbulent high pressure flames this may seriously limit the use of laser diagnostic methods. (author) 1 fig., 2 refs.

  13. Flame acceleration in the early stages of burning in tubes

    Energy Technology Data Exchange (ETDEWEB)

    Bychkov, Vitaly; Fru, Gordon; Petchenko, Arkady [Institute of Physics, Umeaa University, S-901 87 Umeaa (Sweden); Akkerman, V' yacheslav [Institute of Physics, Umeaa University, S-901 87 Umeaa (Sweden); Nuclear Safety Institute (IBRAE) of Russian Academy of Sciences, B. Tulskaya 52, 115191 Moscow (Russian Federation); Eriksson, Lars-Erik [Department of Applied Mechanics, Chalmers University of Technology, 412 96 Goeteborg (Sweden)

    2007-09-15

    Acceleration of premixed laminar flames in the early stages of burning in long tubes is considered. The acceleration mechanism was suggested earlier by Clanet and Searby [Combust. Flame 105 (1996) 225]. Acceleration happens due to the initial ignition geometry at the tube axis when a flame develops to a finger-shaped front, with surface area growing exponentially in time. Flame surface area grows quite fast but only for a short time. The analytical theory of flame acceleration is developed, which determines the growth rate, the total acceleration time, and the maximal increase of the flame surface area. Direct numerical simulations of the process are performed for the complete set of combustion equations. The simulations results and the theory are in good agreement with the previous experiments. The numerical simulations also demonstrate flame deceleration, which follows acceleration, and the so-called ''tulip flames''. (author)

  14. Flame Driving of Longitudinal Instabilities in Liquid Fueled Dump Combustors

    Science.gov (United States)

    1988-10-01

    for the first * natural frequency of 80 Hz. As the flame length is much smaller than the acoustic wavelength at 80 Hz the pressure is constant over...release at different locations along the flame. The reason for this is that the flame length is equivalent to several vortical wavelengths as is evident...pressure minimum there was a large radla- flame length . In all cases, it was ?ound that the tion signal at the driving frequency. On the theory

  15. Acoustic Signature from Flames as a Combustion Diagnostic Tool

    Science.gov (United States)

    1983-11-01

    empirical visual flame length had to be input to the computer for the inversion method to give good results. That is, if the experiment cnd inversion...method were asked to yield the flame length , poor results were obtained. Since this wa3 part of the information sought for practical application of the...to small experimental uncertainty. The method gave reasonably good results for the open flame but substantial input (the flame length ) had to be

  16. Effects of wind velocity and slope on flame properties

    Science.gov (United States)

    David R. Weise; Gregory S. Biging

    1996-01-01

    Abstract: The combined effects of wind velocity and percent slope on flame length and angle were measured in an open-topped, tilting wind tunnel by burning fuel beds composed of vertical birch sticks and aspen excelsior. Mean flame length ranged from 0.08 to 1.69 m; 0.25 m was the maximum observed flame length for most backing fires. Flame angle ranged from -46o to 50o...

  17. Experimental Studies of Hydrocarbon Flame Phenomena: Enabling Combustion Control

    Science.gov (United States)

    2016-07-30

    flames," Physics of Fluids , vol. 7, no. 6, pp. 1447-54, 1995. [8] K. Lyons, " Toward an understanding of the stabilization mechanisms of lifted...Experimental Studies of Hydrocarbon Flame Phenomena: Enabling Combustion Control This report summarizes the research accomplished in the project...34Experimental Studies of Hydrocarbon Flame Phenomena: Enabling Combustion Control". The main areas of activity are: a) electrostatic flame and flow

  18. Ion structure and sequence of ion formation in acetylene flames

    Energy Technology Data Exchange (ETDEWEB)

    Larionova, I.A.; Fialkov, B.S.; Kalinich, K.YA.; Fialkov, A.B.; Ospanov, B.S.

    1993-06-01

    Results of a study of the ion composition of acetylene-air flames burning at low pressures are reported. Data on ion formation are compared for flames of saturated hydrocarbons, oxygen-containing fuels, and acetylene. It is shown that the characteristics of ion formation in the flame front and directly ahead of it are similar to those observed in flames of other fuels. These characteristics, however, are different in the low-temperature region. 9 refs.

  19. Effectiveness of Flame Retardants in TufFoam.

    Energy Technology Data Exchange (ETDEWEB)

    Abelow, Alexis Elizabeth [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Nissen, April [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Massey, Lee Taylor [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Whinnery, LeRoy L. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2017-12-01

    An investigation of polyurethane foam filled with known flame retardant fillers including hydroxides, melamine, phosphate-containing compounds, and melamine phosphates was carried out to produce a low-cost material with high flame retardant efficiency. The impact of flame retardant fillers on the physical properties such a s composite foam density, glass transition temperature, storage modulus, and thermal expansion of composite foams was investigated with the goal of synthesizing a robust rigid foam with excellent flame retardant properties.

  20. White Flame Energy switches to backhoes

    Energy Technology Data Exchange (ETDEWEB)

    Fiscor, S.

    2005-06-01

    The mountaintop coal operator, White Flame Energy has switched to different truck-shovel arrangement. Along with many surface mining operations throughout central Appalachia, the company is using hoe-configured hydraulic excavators as opposed to the traditional front-shovel arrangements. Located in Varney, WV, White Flame Energy uses two Terex O & K mining shovels, an RH170 and an RH 200, which have the capacity to move 2 million cu yards per month from five seams, primarily the Coalburg, Stockton, and No 5 Block and associated rider seams. The article records conversations on the operations with Mike Vines, the general manager, and Don Nicewonder, the owner of White Flame Energy. 2 photos.

  1. Aerothermodynamic properties of stretched flames in enclosures

    Science.gov (United States)

    Rotman, D. A.; Oppenheim, A. K.

    Flames are stretched by being pulled along their frontal surface by the flow field in which they reside. Their trajectories tend to approach particle paths, acquiring eventually the role of contact boundaries, -interfaces between the burnt and unburnt medium that may broaden solely as a consequence of diffusion. Fundamental properties of flow fields governing such flames are determined here on the basis of the zero Mach number model, providng a rational method of approach to the computational analysis of combustion fields in enclosures where, besides the aerodynamic properties flow, the thermodynamic process of compression must be taken into account. To illustrate its application, the method is used to reveal the mechanism of formation of a tulip-shape flame in a rectangular enclosure under nonturbulent flow conditions.

  2. Laminar flame properties and flame acceleration prediction of hydrogen-methane mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Coudoro, K. [Inst. de Combustion, Aerothermique, Reactivite et Environnement CNRS Orleans (France); Inst. de Radioprotection et de Surete Nucleaire, DSR/SAGR, Fontenay-aux-Roses (France); Chaumeix, N. [Inst. de Combustion, Aerothermique, Reactivite et Environnement CNRS Orleans (France); Bentaib, A. [Inst. de Radioprotection et de Surete Nucleaire, DSR/SAGR, Fontenay-aux-Roses (France); Paillard, C-E. [Inst. de Combustion, Aerothermique, Reactivite et Environnement CNRS Orleans (France)

    2011-07-01

    The combustion of a binary mixture of methane and hydrogen has been studied using 2 different experimental setups: the spherical bomb to investigate the fundamental flame properties of this mixture with air, initially at 100 kPa, at different initial temperatures (300 - 363 K) and for a wide range of equivalence ratios (0.8 - 1.4); ENACCEF to investigate the flame acceleration phenomena in smooth tube for mixtures initially at ambient conditions and for equivalence ratios ranging between 0.57 and 0.84. A detailed kinetic mechanism has been used to derive the activation energies needed for the flame acceleration analysis. (author)

  3. Experimental Investigation of Turbulent Flames in Hypersonic Flows

    Science.gov (United States)

    2015-09-01

    the flow direction and (b) typical flame length scales seen in the OH-PLIF image with Mach 4.5 freestream (high turbulence) at P0 = 0.65 bar, T0...flame structures (3 mm) are observed at the upstream location of area 1 where the combustion localization first appears. The typical flame length scale

  4. 30 CFR 75.600-1 - Approved cables; flame resistance.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Approved cables; flame resistance. 75.600-1 Section 75.600-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE... cables; flame resistance. Cables shall be accepted or approved by MSHA as flame resistant. [57 FR 61223...

  5. Flexible PVC flame retarded with expandable graphite

    CSIR Research Space (South Africa)

    Focke, WW

    2014-02-01

    Full Text Available this outstanding fire resistance. Thus flame-retardant (FR) and smoke-suppressant (SS) additives must be incorporated in order to meet product test specifications such as oxygen index, heat release rate, smoke evolution, or the extent of burning [1]. Levchik... plot for the composites fabricated in this work. For a material to be effectively flame retarded both the fire load and the fire growth index should assume low values. Figure 11 shows a dramatic decrease for all the EG composites relative to the neat...

  6. Flame-Vortex Interactions Imaged in Microgravity - To Assess the Theory Flame Stretch

    Science.gov (United States)

    Driscoll, James F.

    2001-01-01

    The goals of this research are to: 1) Assess the Theory of Flame Stretch by operating a unique flame-vortex experiment under microgravity conditions in the NASA Glenn 2.2 Second Drop Tower (drops to identify operating conditions have been completed); 2) Obtain high speed shadowgraph images (500-1000 frames/s) using the drop rig (images were obtained at one-g, and the NASA Kodak RO camera is being mounted on the drop rig); 3) Obtain shadowgraph and PIV images at 1-g while varying the effects of buoyancy by controlling the Froude number (completed); 4) Numerically model the inwardly-propagating spherical flame that is observed in the experiment using full chemistry and the RUN 1DL code (completed); 5) Send images of the flame shape to Dr. G. Patniak at NRL who is numerically simulating the entire flame-vortex interaction of the present experiment (data transfer completed); and 6) Assess the feasibility of obtaining PIV velocity field images in the drop rig, which would be useful (but not required) for our assessment of the Theory of Flame Stretch (PIV images were obtained at one-g using same low laser power that is available from fiber optic cable in drop tower). The motivation for the work is to obtain novel measurement needed to develop a physically accurate model of turbulent combustion that can help in the control of engine pollutants. The unique experiment allows, for the first time, the detailed study of a negatively-curved (negatively stretched) flame, which is one of the five fundamental types of premixed flames. While there have been studies of flat flames, positively-curved (outwardly-propagating) cases and positively-strained (counterflow) cases, this is the first detailed study of a negatively-curved (inwardly-propagating) flame. The first set of drops in the 2.2 Second Drop Tower showed that microgravity provides more favorable conditions for achieving inwardly-propagating flames (IPFs) than 1-g. A vortex interacts with a flame and creates a spherical

  7. Global atmospheric model for mercury including oxidation by bromine atoms

    Directory of Open Access Journals (Sweden)

    C. D. Holmes

    2010-12-01

    Full Text Available Global models of atmospheric mercury generally assume that gas-phase OH and ozone are the main oxidants converting Hg0 to HgII and thus driving mercury deposition to ecosystems. However, thermodynamic considerations argue against the importance of these reactions. We demonstrate here the viability of atomic bromine (Br as an alternative Hg0 oxidant. We conduct a global 3-D simulation with the GEOS-Chem model assuming gas-phase Br to be the sole Hg0 oxidant (Hg + Br model and compare to the previous version of the model with OH and ozone as the sole oxidants (Hg + OH/O3 model. We specify global 3-D Br concentration fields based on our best understanding of tropospheric and stratospheric Br chemistry. In both the Hg + Br and Hg + OH/O3 models, we add an aqueous photochemical reduction of HgII in cloud to impose a tropospheric lifetime for mercury of 6.5 months against deposition, as needed to reconcile observed total gaseous mercury (TGM concentrations with current estimates of anthropogenic emissions. This added reduction would not be necessary in the Hg + Br model if we adjusted the Br oxidation kinetics downward within their range of uncertainty. We find that the Hg + Br and Hg + OH/O3 models are equally capable of reproducing the spatial distribution of TGM and its seasonal cycle at northern mid-latitudes. The Hg + Br model shows a steeper decline of TGM concentrations from the tropics to southern mid-latitudes. Only the Hg + Br model can reproduce the springtime depletion and summer rebound of TGM observed at polar sites; the snowpack component of GEOS-Chem suggests that 40% of HgII deposited to snow in the Arctic is transferred to the ocean and land reservoirs, amounting to a net deposition flux to the Arctic of 60 Mg a−1. Summertime events of depleted Hg0 at Antarctic sites due to subsidence are much better simulated by

  8. Involvement of reactive oxygen species in brominated diphenyl ether-47-induced inflammatory cytokine release from human extravillous trophoblasts in vitro

    International Nuclear Information System (INIS)

    Park, Hae-Ryung; Kamau, Patricia W.; Loch-Caruso, Rita

    2014-01-01

    Polybrominated diphenyl ethers (PBDEs) are widely used flame retardant compounds. Brominated diphenyl ether (BDE)-47 is one of the most prevalent PBDE congeners found in human breast milk, serum and placenta. Despite the presence of PBDEs in human placenta, effects of PBDEs on placental cell function are poorly understood. The present study investigated BDE-47-induced reactive oxygen species (ROS) formation and its role in BDE-47-stimulated proinflammatory cytokine release in a first trimester human extravillous trophoblast cell line, HTR-8/SVneo. Exposure of HTR-8/SVneo cells for 4 h to 20 μM BDE-47 increased ROS generation 1.7 fold as measured by the dichlorofluorescein (DCF) assay. Likewise, superoxide anion production increased approximately 5 fold at 10 and 15 μM and 9 fold at 20 μM BDE-47 with a 1-h exposure, as measured by cytochrome c reduction. BDE-47 (10, 15 and 20 μM) decreased the mitochondrial membrane potential by 47–64.5% at 4, 8 and 24 h as assessed with the fluorescent probe Rh123. Treatment with 15 and 20 μM BDE-47 stimulated cellular release and mRNA expression of IL-6 and IL-8 after 12 and 24-h exposures: the greatest increases were a 35-fold increased mRNA expression at 12 h and a 12-fold increased protein concentration at 24 h for IL-6. Antioxidant treatments (deferoxamine mesylate, (±)α-tocopherol, or tempol) suppressed BDE-47-stimulated IL-6 release by 54.1%, 56.3% and 37.7%, respectively, implicating a role for ROS in the regulation of inflammatory pathways in HTR-8/SVneo cells. Solvent (DMSO) controls exhibited statistically significantly decreased responses compared with non-treated controls for IL-6 release and IL-8 mRNA expression, but these responses were not consistent across experiments and times. Nonetheless, it is possible that DMSO (used to dissolve BDE-47) may have attenuated the stimulatory actions of BDE-47 on cytokine responses. Because abnormal activation of proinflammatory responses can disrupt trophoblast functions

  9. Involvement of reactive oxygen species in brominated diphenyl ether-47-induced inflammatory cytokine release from human extravillous trophoblasts in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hae-Ryung, E-mail: heaven@umich.edu; Kamau, Patricia W.; Loch-Caruso, Rita

    2014-01-15

    Polybrominated diphenyl ethers (PBDEs) are widely used flame retardant compounds. Brominated diphenyl ether (BDE)-47 is one of the most prevalent PBDE congeners found in human breast milk, serum and placenta. Despite the presence of PBDEs in human placenta, effects of PBDEs on placental cell function are poorly understood. The present study investigated BDE-47-induced reactive oxygen species (ROS) formation and its role in BDE-47-stimulated proinflammatory cytokine release in a first trimester human extravillous trophoblast cell line, HTR-8/SVneo. Exposure of HTR-8/SVneo cells for 4 h to 20 μM BDE-47 increased ROS generation 1.7 fold as measured by the dichlorofluorescein (DCF) assay. Likewise, superoxide anion production increased approximately 5 fold at 10 and 15 μM and 9 fold at 20 μM BDE-47 with a 1-h exposure, as measured by cytochrome c reduction. BDE-47 (10, 15 and 20 μM) decreased the mitochondrial membrane potential by 47–64.5% at 4, 8 and 24 h as assessed with the fluorescent probe Rh123. Treatment with 15 and 20 μM BDE-47 stimulated cellular release and mRNA expression of IL-6 and IL-8 after 12 and 24-h exposures: the greatest increases were a 35-fold increased mRNA expression at 12 h and a 12-fold increased protein concentration at 24 h for IL-6. Antioxidant treatments (deferoxamine mesylate, (±)α-tocopherol, or tempol) suppressed BDE-47-stimulated IL-6 release by 54.1%, 56.3% and 37.7%, respectively, implicating a role for ROS in the regulation of inflammatory pathways in HTR-8/SVneo cells. Solvent (DMSO) controls exhibited statistically significantly decreased responses compared with non-treated controls for IL-6 release and IL-8 mRNA expression, but these responses were not consistent across experiments and times. Nonetheless, it is possible that DMSO (used to dissolve BDE-47) may have attenuated the stimulatory actions of BDE-47 on cytokine responses. Because abnormal activation of proinflammatory responses can disrupt trophoblast functions

  10. High-temperature oxidation chemistry of n-butanol--experiments in low-pressure premixed flames and detailed kinetic modeling.

    Science.gov (United States)

    Hansen, N; Harper, M R; Green, W H

    2011-12-07

    An automated reaction mechanism generator is used to develop a predictive, comprehensive reaction mechanism for the high-temperature oxidation chemistry of n-butanol. This new kinetic model is an advancement of an earlier model, which had been extensively tested against earlier experimental data (Harper et al., Combust. Flame, 2011, 158, 16-41). In this study, the model's predictive capabilities are improved by targeting isomer-resolved quantitative mole fraction profiles of flame species in low-pressure flames. To this end, a total of three burner-stabilized premixed flames are isomer-selectively analyzed by flame-sampling molecular-beam time-of-flight mass spectrometry using photoionization by tunable vacuum-ultraviolet synchrotron radiation. For most species, the newly developed chemical kinetic model is capable of accurately reproducing the experimental trends in these flames. The results clearly indicate that n-butanol is mainly consumed by H-atom abstraction with H, O, and OH, forming predominantly the α-C(4)H(9)O radical (CH(3)CH(2)CH(2)˙CHOH). Fission of C-C bonds in n-butanol is only predicted to be significant in a similar, but hotter flame studied by Oßwald et al. (Combust. Flame, 2011, 158, 2-15). The water-elimination reaction to 1-butene is found to be of no importance under the premixed conditions studied here. The initially formed isomeric C(4)H(9)O radicals are predicted to further oxidize by reacting with H and O(2) or to decompose to smaller fragments via β-scission. Enols are detected experimentally, with their importance being overpredicted by the model.

  11. LES of a laboratory-scale turbulent premixed bunsen flame using FSD, PCM-FPI and thickened flame models

    NARCIS (Netherlands)

    Hernandez Perez, F.E.; Yuen, F.T.C.; Groth, C.P.T.; Gülder, O.L.

    2011-01-01

    Large-eddy simulations (LES) of a turbulent premixed Bunsen flame were carried out with three subfilter-scale (SFS) modelling approaches for turbulent premixed combustion. One approach is based on the artificially thickened flame and power-law flame wrinkling models, the second approach is based on

  12. Measurements and Experimental Database Review for Laminar Flame Speed Premixed Ch4/Air Flames

    Science.gov (United States)

    Zubrilin, I. A.; Matveev, S. S.; Matveev, S. G.; Idrisov, D. V.

    2018-01-01

    Laminar flame speed (SL ) of CH4 was determined at atmospheric pressure and initial gas temperatures in range from 298 to 358 K. The heat flux method was employed to measure the flame speed in non-stretched flames. The kinetic mechanism GRI 3.0 [1] were used to simulate SL . The measurements were compared with available literature results. The data determined with the heat flux method agree with some previous burner measurements and disagree with the data from some vessel closed method and counterflow method. The GRI 3.0 mechanism was able to reproduce the present experiments. Laminar flame speed was determined at pressures range from of 1 to 20 atmospheres through mechanism GRI 3.0. Based on experimental data and calculations was obtained SL dependence on pressure and temperature. The resulting of dependence recommended use during the numerical simulation of methane combustion.

  13. The role of diet on long-term concentration and pattern trends of brominated and chlorinated contaminants in western Hudson Bay polar bears, 1991-2007

    International Nuclear Information System (INIS)

    McKinney, Melissa A.; Stirling, Ian; Lunn, Nick J.; Peacock, Elizabeth; Letcher, Robert J.

    2010-01-01

    Adipose tissue was sampled from the western Hudson Bay (WHB) subpopulation of polar bears at intervals from 1991 to 2007 to examine temporal trends of PCB and OCP levels both on an individual and sum-(Σ-)contaminant basis. We also determined levels and temporal trends of emerging polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), polybrominated biphenyls (PBBs) and other current-use brominated flame retardants. Over the 17-year period, Σ DDT (and p,p'-DDE, p,p'-DDD, p,p'-DDT) decreased (-8.4%/year); α-hexachlorocyclohexane (α-HCH) decreased (-11%/year); β-HCH increased (+ 8.3%/year); and Σ PCB and Σ chlordane (CHL), both contaminants at highest concentrations in all years (> 1 ppm), showed no distinct trends even when compared to previous data for this subpopulation dating back to 1968. Some of the less persistent PCB congeners decreased significantly (-1.6%/year to -6.3%/year), whereas CB153 levels tended to increase (+ 3.3%/year). Parent CHLs (c-nonachlor, t-nonachlor) declined, whereas non-monotonic trends were detected for metabolites (heptachlor epoxide, oxychlordane). Σ chlorobenzene, octachlorostyrene, Σ mirex, Σ MeSO 2 -PCB and dieldrin did not significantly change. Increasing Σ PBDE levels (+ 13%/year) matched increases in the four consistently detected congeners, BDE47, BDE99, BDE100 and BDE153. Although no trend was observed, total-(α)-HBCD was only detected post-2000. Levels of the highest concentration brominated contaminant, BB153, showed no temporal change. As long-term ecosystem changes affecting contaminant levels may also affect contaminant patterns, we examined the influence of year (i.e., aging or 'weathering' of the contaminant pattern), dietary tracers (carbon stable isotope ratios, fatty acid patterns) and biological (age/sex) group on congener/metabolite profiles. Patterns of PCBs, CHLs and PBDEs were correlated with dietary tracers and biological group, but only PCB and CHL patterns were correlated with year

  14. Bioaccumulation and biotransformation of brominated and chlorinated contaminants and their metabolites in ringed seals (Pusa hispida) and polar bears (Ursus maritimus) from East Greenland.

    Science.gov (United States)

    Letcher, Robert J; Gebbink, Wouter A; Sonne, Christian; Born, Erik W; McKinney, Melissa A; Dietz, Rune

    2009-11-01

    We report on the comparative bioaccumulation, biotransformation and/or biomagnification from East Greenland ringed seal (Pusa hispida) blubber to polar bear (Ursus maritimus) tissues (adipose, liver and brain) of various classes and congeners of persistent chlorinated and brominated contaminants