Sample records for cargo flame exposure

  1. Characterizing Flame Retardant Applications and Potential Human Exposure in Backpacking Tents.

    Gomes, Genna; Ward, Peyton; Lorenzo, Amelia; Hoffman, Kate; Stapleton, Heather M


    Flame retardant (FR) chemicals are applied to products to meet flammability standards; however, exposure to some additive FRs has been shown to be associated with adverse health effects. Previous research on FR exposure has primarily focused on chemicals applied to furniture and electronics; however, camping tents sold in the United States, which often meet flammability standard CPAI-84, remain largely unstudied in regards to their chemical treatments. In this study, FRs from five brands of CPAI-84-compliant, two-person backpacking tents were measured and potential exposure was assessed. Dermal and inhalation exposure levels were assessed by collecting hand wipes from 20 volunteers before and after tent setup and by using active air samplers placed inside assembled tents, respectively. Organophosphate flame retardants (OPFRs) were the most commonly detected FR in the tent materials and included triphenyl phosphate (TPHP), tris(1,3-dichloro-2-propyl)phosphate (TDCIPP) and tris(2-chloroethyl)phosphate (TCEP). Levels of OPFRS measured on hand wipes were significantly higher post-tent setup compared to pre setup, and in the case of TDCIPP, levels were 29 times higher post setup. OPFRs were also detected at measurable concentrations in the air inside of treated tents. Significant, positive correlations were found between FR levels in treated textiles and measures of dermal and inhalation exposure. These results demonstrate that dermal exposure to FRs occurs from handling camping tents and that inhalation exposure will likely occur while inside a tent. PMID:27082445

  2. Developmental exposure of zebrafish larvae to organophosphate flame retardants causes neurotoxicity.

    Sun, Liwei; Xu, Wenbin; Peng, Tao; Chen, Haigang; Ren, Lin; Tan, Hana; Xiao, Dan; Qian, Haifeng; Fu, Zhengwei


    With the gradual ban on brominated flame retardants (FRs), the application of organophosphate flame retardants (OPFRs) has increased remarkably. Considering the structural similarity between OPFRs and organophosphate pesticides, hypotheses that OPFRs may interfere with neurodevelopment as organophosphate pesticides are reasonable. In this study, the neurotoxicity of three OPFRs, including tri-n-butyl phosphate (TNBP), tris (2-butoxyethyl) phosphate (TBOEP) and tris (2-chloroethyl) phosphate (TCEP), was evaluated in zebrafish larvae and then compared with the neurotoxicity of organophosphate pesticide chlorpyrifos (CPF). The results showed that similar to CPF, exposure to OPFRs for 5days resulted in significant changes in locomotor behavior, either in free swimming or in photomotor response. However, given the transcriptional changes that occur in nervous system genes in response to OPFRs and CPF, as well as the altered enzyme activity of AChE and its mRNA level, the underlying mechanisms for neurotoxicity among these organophosphate chemicals might be varied. In summary, the results confirm the potential neurodevelopmental toxicity of OPFRs and underscore the importance of identifying the mechanistic targets of the OPFRs with specific moieties. Furthermore, as the neurobehavioral responses are well conserved among vertebrates and the exposure of children to OPFRs is significant, a thorough assessment of the risk of OPFRs exposure during early development should be highly emphasized in future studies. PMID:27018022

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

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


    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. METHOD

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

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


    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. Methods This study was part of the prospective Groningen infant COMPARE (Comparison of Exposure-Effect Pathways to Improve the Assessment of Human Health Risks of Complex Environmental Mixtures of Organoha...

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

    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. Brominated flame retardants - Exposure and risk assessment for the general population.

    Fromme, H; Becher, G; Hilger, B; Völkel, W


    Brominated flame retardants (BFRs) are a large group of different substances used in numerous products to prevent fire hazards. Some of them are persistent in the environment, accumulate in the food chain and are of toxicological concern, while for others current data are limited. Meanwhile, BFRs have been found in many environmental media, foods, and biota including humans. This review presents recent findings obtained from monitoring data in environmental media relevant for human exposure, as well as dietary exposure. In this context, concentrations in indoor and ambient air and in house dust are outlined. Furthermore, we summarize human biomonitoring data on BFR levels in blood and breast milk. Current estimates of the overall exposure of the general population using different relevant subsets are also addressed. All of these data are discussed in relation to currently available toxicological reference values used for risk assessment purposes. Obviously, the exposure of the general population varies considerably in different parts of the world and even within countries. Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) show the highest intake during infancy. While the highest intake for BDE 47 for all groups was observed in the US, the total BDE 209 and HBCD intake was highest in the UK. For HBCD and all PBDEs except BDE 209, diet accounts for a large proportion of the total intake during infancy in all countries. With regard to toddlers and adults, the contribution of diet to total intake is high in Germany and the UK, while in the US, the high concentrations of PBDE in dust resulted in a notably smaller proportion of the intake being attributed to diet. PMID:26412400

  7. Low level exposure to the flame retardant BDE-209 reduces thyroid hormone levels and disrupts thyroid signaling in fathead minnows

    Noyes, Pamela D.; Lema, Sean C.; Macaulay, Laura J.; Douglas, Nora K.; Stapleton, Heather M.


    Polybrominated diphenyl ether (PBDE) flame retardants have been shown to disrupt thyroid hormone regulation, neurodevelopment, and reproduction in some animals. However, effects of the most heavily used PBDE, decabromodiphenyl ether (BDE-209), on thyroid functioning remain unclear. This study examined low-dose effects of BDE-209 on thyroid hormone levels and signaling in fathead minnows. Adult males received dietary exposures of BDE-209 at a low dose (~3 ng/g bw-day) and high dose (~300 ng/g ...

  8. Size-dependent atmospheric deposition and inhalation exposure of particle-bound organophosphate flame retardants.

    Luo, Pei; Bao, Lian-Jun; Guo, Ying; Li, Shao-Meng; Zeng, Eddy Y


    Atmospheric size-fractionated particles were collected at different heights in an e-waste recycling zone (QY) and urban Guangzhou (GZ), China and analyzed for organophosphate flame retardants (OPFRs). The total air concentrations of eight OPFRs were 130±130 and 138±127 ng m(-3) in QY and GZ, respectively. Compositional profiles of chlorinated OPFRs were different between QY and GZ, but the size distribution patterns of all OPFRs were not significantly different at different heights. Estimated atmospheric deposition fluxes of OPFRs were 51±67 and 55±13 μg m(-2) d(-1) in QY and GZ, respectively, and the coarse particles (Dp>1.8 μm) dominated both the dry and wet deposition fluxes. Moreover, not all particle-bound OPFRs were inhalable and deposited in the human respiratory tract. The calculated inhalation doses of OPFRs were much lower than the reference doses, suggesting that potential health risk due to inhalation exposure to particle-bound OPFRs in the e-waste recycling zone and urban site was low. PMID:26414926

  9. Rice ingestion is a major pathway for human exposure to organophosphate flame retardants (OPFRs) in China.

    Zhang, Xingli; Zou, Wei; Mu, Li; Chen, Yuming; Ren, Chaoxiu; Hu, Xiangang; Zhou, Qixing


    Although organophosphate flame retardants (OPFRs) have been shown to accumulate in abiotic and biotic environmental compartments, data about OPFRs concentrations in various foods are limited and are none in humans through diets. In this work, the concentrations of 6 typical OPFRs were investigated in 50 rice samples, 75 commonly consumed foods and 45 human hair samples from China. The dietary intakes of OPFRs for adult people via food ingestion were estimated. The concentrations of ΣOPFRs in foods ranged from 0.004ng/g to 287ng/g. OPFRs were detected in 53.3% of the human hair samples. The highest OPFRs concentrations were found in rice and vegetables. Tri(2-chloroethyl)phosphate(TCEP), tris(2-chloroisopropyl)phosphate(TCIPP), and tri(2-ethyltexyl)phosphate(TEHP) were predominant in all food samples. OPFRs concentrations in foods were not significantly affected by the packaging materials. The mean dietary intakes of ΣOPFRs for adult males and females were 539 and 601ng/kg body weight/day, respectively. The greatest contribution to these values is from rice, accounting for approximately 60% of the total intake, particularly from rice protein. Rice ingestion was considered a potential major pathway for human exposure to OPFRs, and regional differences in the levels of OPFRs in foods and dietary differences should be given more attention in the future. PMID:27484948

  10. Exposure to organophosphate and polybrominated diphenyl ether flame retardants via indoor dust and childhood asthma.

    Canbaz, D; van Velzen, M J M; Hallner, E; Zwinderman, A H; Wickman, M; Leonards, P E G; van Ree, R; van Rijt, L S


    Although the ubiquitous detection of polybrominated diphenyl ether (PBDE) and organophosphate flame retardants (PFRs) in indoor dust has raised health concerns, only very few epidemiological studies have assessed their impact on human health. Inhalation of dust is one of the exposure routes of FRs, especially in children and can be hazardous for the respiratory health. Moreover, PFRs are structurally similar to organophosphate pesticides, which have been associated with allergic asthma. Thus, we investigated whether the concentrations of PFRs and PBDEs in indoor dust are associated with the development of childhood asthma. We selected 110 children who developed asthma at 4 or at 8 years old and 110 matched controls from a large prospective birth cohort (BAMSE - Barn, Allergy, Milieu Stockholm Epidemiology). We analyzed the concentrations of 7 PFRs and 21 PBDEs in dust collected around 2 months after birth from the mother's mattress. The abundance rank in dust was as follows: TBOEP⪢TPHP>mmp-TMPP>EHDPHP~TDCIPP>TCEP~TCIPP~BDE-209⪢BDE-99>BDE-47>BDE-153>BDE-183>BDE-100. There was no positive association between the FRs in mattress dust and the development of childhood asthma. In contrast, dust collected from mattresses of the mothers of children who would develop asthma contained significant lower levels of TPHP and mmp-TMPP. This study provides data on a wide range of PFRs and PBDEs in dust samples and development of asthma in children. PMID:25952720

  11. Reproductive changes in American kestrels (Falco sparverius) in relation to exposure to technical hexabromocyclododecane flame retardant.

    Fernie, Kim J; Marteinson, Sarah C; Bird, David M; Ritchie, Ian J; Letcher, Robert J


    Recently, the ban of hexabromocyclododecane (HBCD), a high-production-volume flame retardant, was announced in Europe and North America. However, the effects of HCBD remain understudied in birds. The objectives of the present comparative effects study were to determine whether exposure to an HBCD technical mixture (HBCD-TM) altered avian reproductive measures at an environmentally relevant concentration. American kestrels were exposed daily by food to HBCD-TM, i.e., 0.51 µg HBCD/g kestrel/d; exposed kestrels laid eggs that had α-HBCD concentrations (163.5 ± 75.1 ng/g wet wt) tenfold greater than β- and γ-HBCD isomers, an isomer profile and concentrations similar to those of eggs of wild peregrine falcons (Falco peregrinus). Concentrations of HBCD were not detected in the control kestrel eggs. In comparison with controls, the kestrels exposed to HBCD began to lay their eggs 6 d earlier and laid larger clutches of smaller eggs. The size of the eggs was inversely correlated with the in ovo α-HBCD concentrations. The smaller eggs of the HBCD exposed kestrels also lost more weight by midincubation, suggesting increased eggshell porosity since eggshell thickness was comparable. Generally birds that lay more eggs and lay earlier in the breeding season gain the advantage of better hatching and fledging success, yet the kestrels exposed to HBCD failed to have better reproductive success than the control birds. These reproductive changes were a function of HBCD exposure, likely through changes in food consumption, with possible impacts on, for example, reproductive behavior and/or alterations in thyroid hormones. PMID:21898552

  12. Effects of flame made zinc oxide particles in human lung cells - a comparison of aerosol and suspension exposures

    Raemy David O


    Full Text Available Abstract Background Predominantly, studies of nanoparticle (NPs toxicology in vitro are based upon the exposure of submerged cell cultures to particle suspensions. Such an approach however, does not reflect particle inhalation. As a more realistic simulation of such a scenario, efforts were made towards direct delivery of aerosols to air-liquid-interface cultivated cell cultures by the use of aerosol exposure systems. This study aims to provide a direct comparison of the effects of zinc oxide (ZnO NPs when delivered as either an aerosol, or in suspension to a triple cell co-culture model of the epithelial airway barrier. To ensure dose–equivalence, ZnO-deposition was determined in each exposure scenario by atomic absorption spectroscopy. Biological endpoints being investigated after 4 or 24h incubation include cytotoxicity, total reduced glutathione, induction of antioxidative genes such as heme-oxygenase 1 (HO–1 as well as the release of the (pro-inflammatory cytokine TNFα. Results Off-gases released as by-product of flame ZnO synthesis caused a significant decrease of total reduced GSH and induced further the release of the cytokine TNFα, demonstrating the influence of the gas phase on aerosol toxicology. No direct effects could be attributed to ZnO particles. By performing suspension exposure to avoid the factor “flame-gases”, particle specific effects become apparent. Other parameters such as LDH and HO–1 were not influenced by gaseous compounds: Following aerosol exposure, LDH levels appeared elevated at both timepoints and the HO–1 transcript correlated positively with deposited ZnO-dose. Under submerged conditions, the HO–1 induction scheme deviated for 4 and 24h and increased extracellular LDH was found following 24h exposure. Conclusion In the current study, aerosol and suspension-exposure has been compared by exposing cell cultures to equivalent amounts of ZnO. Both exposure strategies differ fundamentally in their

  13. Design of an experiment to measure the fire exposure of radioactive materials packages aboard container cargo ships

    The test described in this paper is intended to measure the typical accident environment for a radioactive materials package in a fire aboard a container cargo ship. A stack of nine used standard cargo containers will be variously loaded with empty packages, simulated packages and combustible cargo and placed over a large hydrocarbon pool fire of one hour duration. Both internal and external fire container fire environments typical of on-deck stowage will be measured as well as the potential for container to container fire spread. With the use of the inverse heat conduction calculations, the local heat transfer to the simulated packages can be estimated from thermocouple data. Data recorded will also provide information on fire durations in each container, fire intensity and container to container fire spread characteristics

  14. Design of an experiment to measure the fire exposure of radioactive materials packages aboard container cargo ships

    Koski, J.A.


    The test described in this paper is intended to measure the typical accident environment for a radioactive materials package in a fire aboard a container cargo ship. A stack of nine used standard cargo containers will be variously loaded with empty packages, simulated packages and combustible cargo and placed over a large hydrocarbon pool fire of one hour duration. Both internal and external fire container fire environments typical of on-deck stowage will be measured as well as the potential for container to container fire spread. With the use of the inverse heat conduction calculations, the local heat transfer to the simulated packages can be estimated from thermocouple data. Data recorded will also provide information on fire durations in each container, fire intensity and container to container fire spread characteristics.

  15. Environmental occurrence, analysis and human exposure to the flame retardant tetrabromobisphenol-A (TBBP-A)-A review.

    Abou-Elwafa Abdallah, Mohamed


    TBBP-A is a high production volume chemical applied widely as a flame retardant in printed circuit boards. Recent studies have raised concern over potential harmful implications of TBBP-A exposure in human and wildlife, leading to its classification under group 2A "Probably carcinogenic to humans" by the International Agency for Research on Cancer. This article provides a comprehensive review of the available literature on TBBP-A analysis, environmental levels and human exposure. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been identified as the method of choice for robust, accurate and sensitive analysis of TBBP-A in different matrices. TBBP-A has been detected in almost all environmental compartments all over the world, rendering it a ubiquitous contaminant. Human exposure studies revealed dust ingestion and diet as the major pathways of TBBP-A exposure in the general population. Toddlers are likely to be more exposed than adults via accidental indoor dust ingestion. Moreover, exposure to TBBP-A may occur prenatally and via breast milk. There are no current restrictions on the production of TBBP-A in the EU or worldwide. However, more research is required to characterise human exposure to TBBP-A in and around production facilities, as well as in e-waste recycling regions. PMID:27266836

  16. Exposure to brominated flame retardant PBDE-99 affects cytoskeletal protein expression in the neonatal mouse cerebral cortex

    Alm, Henrik; Kultima, Kim; Scholz, Birger;


    Polybrominated diphenyl ethers (PBDEs) are environmental contaminants found in human and animal tissues worldwide. Neonatal exposure to the flame retardant 2,2', 4,4',5-pentabromodiphenyl ether (PBDE-99) disrupts normal brain development in mice, and results in disturbed spontaneous behavior in the...... adult. The mechanisms underlying the late effects of early exposure are not clear. To gain insight into the initial neurodevelopmental damage inflicted by PBDE-99, we investigated the short-term effects of PBDE-99 on protein expression in the developing cerebral cortex of neonatal mice, and the......-3 activity. These results indicate that the permanent neurological damage induced by PBDE-99 during the brain growth spurt involve detrimental effects on cytoskeletal regulation and neuronal maturation in the developing cerebral cortex....

  17. Neurobehavioral function and low-level exposure to brominated flame retardants in adolescents: a cross-sectional study

    Kiciński Michał


    Full Text Available Abstract Background Animal and in vitro studies demonstrated a neurotoxic potential of brominated flame retardants, a group of chemicals used in many household and commercial products to prevent fire. Although the first reports of detrimental neurobehavioral effects in rodents appeared more than ten years ago, human data are sparse. Methods As a part of a biomonitoring program for environmental health surveillance in Flanders, Belgium, we assessed the neurobehavioral function with the Neurobehavioral Evaluation System (NES-3, and collected blood samples in a group of high school students. Cross-sectional data on 515 adolescents (13.6-17 years of age was available for the analysis. Multiple regression models accounting for potential confounders were used to investigate the associations between biomarkers of internal exposure to brominated flame retardants [serum levels of polybrominated diphenyl ether (PBDE congeners 47, 99, 100, 153, 209, hexabromocyclododecane (HBCD, and tetrabromobisphenol A (TBBPA] and cognitive performance. In addition, we investigated the association between brominated flame retardants and serum levels of FT3, FT4, and TSH. Results A two-fold increase of the sum of serum PBDE’s was associated with a decrease of the number of taps with the preferred-hand in the Finger Tapping test by 5.31 (95% CI: 0.56 to 10.05, p = 0.029. The effects of the individual PBDE congeners on the motor speed were consistent. Serum levels above the level of quantification were associated with an average decrease of FT3 level by 0.18 pg/mL (95% CI: 0.03 to 0.34, p = 0.020 for PBDE-99 and by 0.15 pg/mL (95% CI: 0.004 to 0.29, p = 0.045 for PBDE-100, compared with concentrations below the level of quantification. PBDE-47 level above the level of quantification was associated with an average increase of TSH levels by 10.1% (95% CI: 0.8% to 20.2%, p = 0.033, compared with concentrations below the level of quantification. We did not

  18. Occupational exposure to brominated flame retardants : With emphasis on polybrominated diphenyl ethers

    Thuresson, Kaj


    Brominated flame retardants (BFRs) are a diverse group of chemicals, which are used to slow down or inhibit the development of fires. BFRs are incorporated into a wide range of consumer products that are considered as potential fire hazards, such as TV-sets, household appliances, computers, and textiles. The production and use of BFRs is extensive and consists of mainly tetrabromobisphenol A (TBBPA), polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecan (HBCD). BFRs in general, but...

  19. Brominated and organophosphate flame retardants in indoor dust of Jeddah, Kingdom of Saudi Arabia: Implications for human exposure.

    Ali, Nadeem; Eqani, Syed Ali Musstjab Akber Shah; Ismail, Iqbal Mohammad Ibrahim; Malarvannan, Govindan; Kadi, Mohammad W; Albar, Hussain Mohammed Salem; Rehan, Mohammad; Covaci, Adrian


    Different flame retardants (FRs) namely polybrominated diphenyl ethers (PBDEs), emerging brominated/chlorinated flame retardants (Br/Cl FRs), and organophosphate FRs (OPFRs) were analyzed in cars, air conditioner (AC) filters and floor dust of different households from Jeddah, Kingdom of Saudi Arabia (KSA). To the best of our knowledge, this is first study in literature reporting emerging Br/Cl FRs and OPFRs in AC filter dust and also first to report on their occurrence in dust from KSA. Chlorinated alkyl phosphate, penta-BDEs, BDE-209, and decabromodiphenylethane (DBDPE) were the major chemicals in dust samples from all microenvironments. ΣOPFRs occurred at median concentrations (ng/g dust) of 15,400, 10,500, and 3750 in AC filter, car and house floor dust, respectively. For all analyzed chemicals, relatively lower levels were observed in floor dust than car and AC filter dust. The profiles of FRs in car dust were different from AC filter and floor dust, which reflected their wider application as FR and plasticizer in variety of household and commercial products. For toddlers, assuming high dust intake and 95th percentile concentrations, the computed exposure estimation for BDE-99 was higher than RfD values. PMID:27343946

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

    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.


    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.

  1. Exposure of male mice to two kinds of organophosphate flame retardants (OPFRs) induced oxidative stress and endocrine disruption.

    Chen, Guanliang; Jin, Yuanxiang; Wu, Yan; Liu, Ling; Fu, Zhengwei


    Triphenyl phosphate (TPP) and tris(2-chloroethyl) phosphate (TCEP) are two of the most common organophosphate flame retardants in the ecosystem. Effects of TPP and TCEP on the induction of oxidative stress and endocrine disruption were evaluated in five weeks old male mice. After receiving 100, 300 mg/kg/bodyweight oral exposure to TPP and TCEP for 35 days, the body and testis weights decreased in 300 mg/kg TPP and TCEP treated groups. Hepatic malondialdehyde (MDA) contents increased significantly in both TPP treated groups, while the contents of glutathione (GSH) decreased significantly in 300 mg/kg TPP and both TCEP treated groups. In addition, the hepatic activities of antioxidant enzymes including glutathione peroxidase (GPX), catalase (CAT) and glutathione S-transferase (GST) as well as their related gene expression were affected by TPP or TECP exposure. On the other hand, 300 mg/kg of TPP or TECP treatment resulted in histopathological damage and the decrease of testicular testosterone levels. Moreover, the expression of main genes related to testosterone synthesis including steroidogenic acute regulatory protein (StAR), low-density lipoprotein receptor (LDL-R), cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc) and cytochrome P450 17α-hydroxysteroid dehydrogenase (P450-17α) in the testes also decreased after the exposure to 300 mg/kg TPP or TCEP for 35 days. Combined with the effects on physiology, histopathology and the expression of genes, TPP and TCEP can induce oxidative stress and endocrine disruption in mice. PMID:26183808

  2. Analysis of human hair to assess exposure to organophosphate flame retardants: Influence of hair segments and gender differences.

    Qiao, Lin; Zheng, Xiao-Bo; Zheng, Jing; Lei, Wei-Xiang; Li, Hong-Fang; Wang, Mei-Huan; He, Chun-Tao; Chen, She-Jun; Yuan, Jian-Gang; Luo, Xiao-Jun; Yu, Yun-Jiang; Yang, Zhong-Yi; Mai, Bi-Xian


    Hair is a promising, non-invasive, human biomonitoring matrix that can provide insight into retrospective and integral exposure to organic pollutants. In the present study, we measured the concentrations of organophosphate flame retardants (PFRs) in hair and serum samples from university students in Guangzhou, China, and compared the PFR concentrations in the female hair segments using paired distal (5~10cm from the root) and proximal (0~5cm from the root) samples. PFRs were not detected in the serum samples. All PFRs except tricresyl phosphate (TMPP) and tri-n-propyl phosphate (TPP) were detected in more than half of all hair samples. The concentrations of total PFRs varied from 10.1 to 604ng/g, with a median of 148ng/g. Tris(chloroisopropyl) phosphate (TCIPP) and tri(2-ethylexyl) phosphate (TEHP) were the predominant PFRs in hair. The concentrations of most PFRs in the distal segments were 1.5~8.6 times higher than those in the proximal segments of the hair (t-test, p<0.05), which may be due to the longer exposure time of the distal segments to external sources. The values of log (PFR concentrations-distal/PFR concentrations-proximal) were positively and significantly correlated with log KOA of PFRs (p<0.05, r=0.68), indicating that PFRs with a higher log KOA tend to accumulate in hair at a higher rate than PFRs with a lower log KOA. Using combined segments of female hair, significantly higher PFR concentrations were observed in female hair than in male hair. In contrast, female hair exhibited significantly lower PFR concentrations than male hair when using the same hair position for both genders (0-5cm from the scalp). The controversial results regarding gender differences in PFRs in hair highlight the importance of segmental analysis when using hair as an indicator of human exposure to PFRs. PMID:27078091

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

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


    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. PMID:27064612

  4. 46 CFR 154.534 - Cargo pumps and cargo compressors.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo pumps and cargo compressors. 154.534 Section 154... Equipment Cargo and Process Piping Systems § 154.534 Cargo pumps and cargo compressors. Cargo pumps and cargo compressors must shut-down automatically when the quick-closing shut-off valves under §§...

  5. Developmental Exposure to Organophosphate Flame Retardants Elicits Overt Toxicity and Alters Behavior in Early Life Stage Zebrafish (Danio rerio)

    Dishaw, Laura V.; Hunter, Deborah L.; Padnos, Beth; Padilla, Stephanie; Stapleton, Heather M.


    Organophosphate flame retardants (OPFRs) are common replacements for the phased-out polybrominated diphenyl ethers (PBDEs) and have been detected at high concentrations in environmental samples. OPFRs are structurally similar to organophosphate pesticides and may adversely affect the developing nervous system. This study evaluated the overt toxicity, uptake, and neurobehavioral effects of tris (1,3-dichloro-2-propyl) phosphate (TDCPP), tris (2-chloroethyl) phosphate (TCEP), tris (1-chloro-2-p...

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

    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

  7. Rocket flames

    W. M. Vaidya


    Full Text Available Among the important parameters which characterize the rocket flames are the (1 velocity, (2 pressure, (3 temperature of the exhaust gases and (4 the nature of chemical reactions in the flame of such gases. For the determination of these quantities ordinary methods fail because the flow of exhaust gases is supersonic in character. An introduction of a probe or any foreign body will create such strong disturbances in the supersonic flow that the readings of observing instruments will have no value. Spectroscopic methods are therefore eminently suitable because observations can be taken on the flame under running conditions.

  8. Flame Length

    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...


    The increased use of organophosphorus compounds as alternatives to brominated flame retardants (BFRs) has led to widespread human exposure, There is, however, limited information on their potential health effects. This study compared the effects of nii ne organophosphorus flame...

  10. Groupage Cargo Transportation Model

    Aleksejevs Ruslans; Guseinovs Raufs; Medvedev Alexander N.; Guseynov Sharif E.


    In this work we consider a specific problem of optimal planning of maritime transportation of multiproduct cargo by ships of one (corporate strategy) or several (partially corporate strategy) companies: the core of the problem consists of the existence of the network of intermediate seaports (i.e. transitional seaports), where for every ship arrived the cargo handling is done, and which are situated between the starting and the finishing seaports. In this work, there are mathematical models b...

  11. Is the bone tissue of ring-billed gulls breeding in a pollution hotspot in the St. Lawrence River, Canada, impacted by halogenated flame retardant exposure?

    Plourde, Stéphanie Pellerin; Moreau, Robert; Letcher, Robert J; Verreault, Jonathan


    Bone metabolism is a tightly regulated process that controls bone remodeling and repair in addition to maintaining circulating calcium and phosphate levels. It has been shown that certain organohalogen contaminants may adversely impact bone tissue metabolism and structure in wildlife species. However, exceedingly few studies have addressed the bone-related effects of organohalogen exposure in birds. The objective of the present study was to investigate the associations between markers of bone metabolism and structural integrity, and concentrations of established and current-use halogenated flame retardants (FRs) in ring-billed gulls (Larus delawarensis) nesting in a known FR hotspot area in the St. Lawrence River (Montreal, Canada). Bone metabolism was assessed using plasma calcium and inorganic phosphate levels, and alkaline phophatase activity, while bone (tarsus; trabecular and cortical sections) structure quality was examined using the percentage of bone tissue comprised in the total bone volume (Bv/Tv) and bone mineral density (BMD). Bv/Tv and BMD of the tarsus tended (not significant) to be positively associated with circulating calcium levels in male ring-billed gulls. Moreover, concentrations of FRs in male bird liver (brominated diphenyl ether (BDE)-154, -183, -201, and -209) and plasma (BDE-209) were negatively correlated with trabecular and cortical BMD of the tarsus. These correlative associations may suggest light demineralization of bone tissue associated with FR exposure in male ring-billed gulls. Present findings provide some evidence that bone (tarsus) metabolism and mineral composition may be impacted in high FR-exposed (mainly to PBDEs) ring-billed gulls breeding in the highly urbanized Montreal region. PMID:24016627

  12. Groupage Cargo Transportation Model

    Aleksejevs Ruslans


    Full Text Available In this work we consider a specific problem of optimal planning of maritime transportation of multiproduct cargo by ships of one (corporate strategy or several (partially corporate strategy companies: the core of the problem consists of the existence of the network of intermediate seaports (i.e. transitional seaports, where for every ship arrived the cargo handling is done, and which are situated between the starting and the finishing seaports. In this work, there are mathematical models built from scratch in the form of multicriteria optimization problem; then the goal attainment method of Gembicki is used for reducing the built models to a one-criterion problem of linear programming.

  13. 46 CFR 154.315 - Cargo pump and cargo compressor rooms.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo pump and cargo compressor rooms. 154.315 Section... Equipment Ship Arrangements § 154.315 Cargo pump and cargo compressor rooms. (a) Cargo pump rooms and cargo compressor rooms must be above the weather deck and must be within the cargo area. (b) Where pumps...

  14. BNFL's experience in preparing and implementing radiation protection programmes for the control of exposure to workers involved with the international transport of nuclear cargoes

    BNFL International Transport have successfully developed appropriate Radiation Protection Programmes for their business. The business supports BNFL's worldwide Nuclear Fuel Services with key customer bases in Europe, Japan and the UK, utilising marine, rail and road modal transports. Experience in the business spans over 4 decades. The preparation of RPP's for each aspect of its operations has been made relatively straight forward in that the key elements within the internationally recognised model RPP (by WNTI) were already in place in BNFL's procedures to satisfy current National UK and International Regulations. Arrangements are supported by Management systems which comply with International Standards for Quality Assurance. Exposure to key worker groups continues to be within Category 1 (less than 1mSv/y) of the IAEA Transport Regulations TS-R-1 (ST-1 revised)

  15. Enfermeiros com cargos de chefia e medidas preventivas à exposição ocupacional: facilidades e barreiras Enfermeros con cargos de jefe y medidas preventivas a la exposición ocupacional: facilidades y barreras Nurses in leading positions and measures to prevent occupational exposure: facilities and barriers

    Silmara Elaine Malaguti


    Full Text Available Este estudo descritivo teve como objetivo avaliar as facilidades e barreiras enfrentadas por enfermeiros com cargo de chefia quanto às medidas preventivas à exposição ocupacional envolvendo material biológico, tendo como base o Modelo de Crenças em Saúde de Rosenstock. O estudo foi realizado com 87 enfermeiros de um hospital-escola do interior paulista em 2006. Os dados foram coletados através de um roteiro semi-estruturado, com questões abertas e fechadas e analisados pela técnica de Análise de Conteúdo. O equipamento de proteção individual foi citado como a maior facilidade para a prevenção de acidentes, porém a falta de adesão ao uso e o uso incorreto foram referidos como barreiras para a prevenção de acidentes e como os principais motivos para a ocorrência destes. É importante que estes enfermeiros estejam preparados para desenvolver estratégias individualizadas e motivadoras para adesão ao uso do equipamento de proteção individual em seus setores de trabalho.En este estudio descriptivo se tuvo como objetivo evaluar las facilidades y barreras enfrentadas por enfermeros con cargo de jefe en cuanto a las medidas preventivas a la exposición ocupacional que involucre material biológico, teniendo como base el Modelo de Creencias en Salud de Rosenstock. El estudio fue realizado con 87 enfermeros de un hospital escuela del interior de Sao Paulo, en el 2006. Los datos fueron recolectados a través de una guía de entrevista semi-estructurada, con preguntas abiertas y cerradas y analizados con la técnica del Análisis de Contenido. El equipamiento de protección individual fue citado como la mayor facilidad para la prevención de accidentes, no obstante la falta de adhesión al uso y uso incorrecto fueron referidos como barreras para la prevención de accidentes y como los principales motivos para que éstos ocurran. Es importante que estos enfermeros estén preparados para desarrollar estrategias individualizadas y

  16. Pilot study on the dietary habits and lifestyles of girls with idiopathic precocious puberty from the city of Rome: potential impact of exposure to flame retardant polybrominated diphenyl ethers.

    Tassinari, Roberta; Mancini, Francesca R; Mantovani, Alberto; Busani, Luca; Maranghi, Francesca


    Puberty is regulated by the endocrine system, which when disrupted can affect reproductive health. Endocrine disrupters (ED) are involved in the pathogenesis of idiopathic central precocious puberty (ICPP). Polybrominated diphenyl ethers (PBDE) are lipophilic, persistent ED used as flame retardants in several products; thus, human population is exposed through food and domestic dust. PBDE exposure during the peripubertal period is suspected to interfere with reproductive development. The study aimed to investigate PBDE serum concentration in 31 girls with ICPP as well as describe their dietary habits and lifestyles. The PBDE median level was 59 ng/g of lipids, higher than in healthy girls in comparable studies. Interestingly, elder girls and girls with higher body mass index (BMI) showed higher PBDE serum levels. Considering the relevance of altered puberty onset as a risk factor for reproductive health, studies on food contribution to PBDE exposure in Italian children, and efforts to ameliorate risk assessment for emerging chemicals are suggested. PMID:26226124

  17. Flame structure of methane inverse diffusion flame

    Elbaz, Ayman M.


    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.

  18. Cargo-cult training

    Magueijo, João


    Richard Feynman, in one of his famous rants, evoked as a metaphor what he called "cargo-cult science". During the Second World War, the indigenous people of the South Pacific became accustomed to US Air Force planes landing on their islands, invariably bringing a profusion of desirable goods and tasty foods. When the war ended, they were distressed by the discontinuation of this popular service. So, they decided to take action. They cleared elongated patches of land to make them look like runways. They lit wood fires where they had seen electric floodlights guiding in the planes. They built a wooden shack and made a man sit inside with two halves of a coconut on each ear and bamboo bars sticking out like antennas: he was the "air controller". And they waited for the planes to return.

  19. Operational efficiency in STS cargo processing

    Wilson, R. E.


    A multifaceted program is presented that addresses both the operational aspects of Shuttle-cargo integration and the needs of the STS Cargo Community. The program consists of the following key elements: (1) processing team awareness of cargo needs and requirements; (2) standardization of Orbiter preparation and cargo integration procedures and methods; (3) maximum application of state-of-the-art ADP techniques in all relevant areas; (4) continual review of cargo integration facility and ground system capabilities versus requirements and enhancement; (5) continual assessment of proposed cargo processing changes for safety and other needs; and (6) review of cargo processing philosophies, policies, and concepts for potential improvements.

  20. Turbulent Flames in Supernovae

    Khokhlov, A. M.


    First results of three-dimensional simulations of a thermonuclear flame in Type Ia supernovae are obtained using a new flame-capturing algorithm, and a PPM hydrodynamical code. In the absence of gravity, the flame is stabilized with respect to the Landau (1944) instability due to the difference in the behaviour of convex and concave portions of the perturbed flame front. The transition to turbulence in supernovae occurs on scales =~ 0.1 - 10 km in agreement with the non-linear estimate lambda =~ 2pi D(2_l/geff) based on the Zeldovich (1966) model for a perturbed flame when the gravity acceleration increases; D_l is the normal speed of the laminar flame, and geff is the effective acceleration. The turbulent flame is mainly spread by large scale motions driven by the Rayleigh-Taylor instability. Small scale turbulence facilitates rapid incineration of the fuel left behind the front. The turbulent flame speed D_t approaches D_t =~ U', where U' is the root mean square velocity of turbulent motions, when the turbulent flame forgets initial conditions and reaches a steady state. The results indicate that in a steady state the turbulent flame speed should be independent of the normal laminar flame speed D_l. The three-dimensional results are in sharp contrast with the results of previous two-dimensional simulations which underestimate flame speed due to the lack of turbulent cascade directed in three dimensions from big to small spatial scales. The work was supported by the NSF grants AST 92-18035 and AST 93-005P.

  1. Diffusion Flame Stabilization

    Takahashi, Fumiaki; Katta, Viswanath R.


    Diffusion flames are commonly used for industrial burners in furnaces and flares. Oxygen/fuel burners are usually diffusion burners, primarily for safety reasons, to prevent flashback and explosion in a potentially dangerous system. Furthermore, in most fires, condensed materials pyrolyze, vaporize, and burn in air as diffusion flames. As a result of the interaction of a diffusion flame with burner or condensed-fuel surfaces, a quenched space is formed, thus leaving a diffusion flame edge, which plays an important role in flame holding in combustion systems and fire spread through condensed fuels. Despite a long history of jet diffusion flame studies, lifting/blowoff mechanisms have not yet been fully understood, compared to those of premixed flames. In this study, the structure and stability of diffusion flames of gaseous hydrocarbon fuels in coflowing air at normal earth gravity have been investigated experimentally and computationally. Measurements of the critical mean jet velocity (U(sub jc)) of methane, ethane, or propane at lifting or blowoff were made as a function of the coflowing air velocity (U(sub a)) using a tube burner (i.d.: 2.87 mm) (Fig. 1, left). By using a computational fluid dynamics code with 33 species and 112 elementary reaction steps, the internal chemical-kinetic structures of the stabilizing region of methane and propane flames were investigated (Fig. 1, right). A peak reactivity spot, i.e., reaction kernel, is formed in the flame stabilizing region due to back-diffusion of heat and radical species against an oxygen-rich incoming flow, thus holding the trailing diffusion flame. The simulated flame base moved downstream under flow conditions close to the measured stability limit.

  2. Flat flame burner

    Matsumura, Y.; Mitsudomi, H.


    Osaka Gas Co., Ltd.'s new flat-flame burner has an air-swirling chamber with a flame opening in one side so constructed that combustion gas is forced out from the flame opening in a spiral direction by the swirling air current within the air chamber. The orifice effect of permitting the flame to emanate from a small opening to an unconfined outer space assures formation of a flat flame spreading out over a very wide area, thereby ensuring very rapid, uniform and highly efficient heat treatment of an article to be heated. With the present invention, moreover, it is possible to materially reduce the thickness of the overall device.

  3. Unsteady Flame Embedding

    El-Asrag, Hossam A.


    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.

  4. 49 CFR 1544.228 - Access to cargo and cargo screening: Security threat assessments for cargo personnel in the...


    ... threat assessments for cargo personnel in the United States. 1544.228 Section 1544.228 Transportation... COMMERCIAL OPERATORS Operations § 1544.228 Access to cargo and cargo screening: Security threat assessments... paragraph (b) of this section— (1) Each individual must successfully complete a security threat...

  5. Measurements of a high-luminosity flame structure by a shuttered PIV system

    It is difficult to measure the velocity distribution inside a high-luminosity flame by using the particle image velocimetry (PIV) system with a double-shutter mode CCD camera. The second raw image of the PIV image pair is usually contaminated by flame emission. The main cause of the problem is an excess exposure time which lets the flame emission overlap the particle image in the second frame. If the flame-contamination problem is not significant, for example in faint flames, digital image processing can improve the image to an acceptable level. Nevertheless, when the PIV technique is applied to high-luminosity flames, the second raw particle image would be contaminated by flame emission. In this paper, incorporating a mechanical shutter in the PIV system with a double-shutter CCD camera is proposed to improve PIV measurements in high-luminosity flames. Measurements in faint, high-luminosity as well as very bright flames were tested. The results show that the present setup can accurately resolve the flow velocity field inside the flame cone, through the flame and in the post flame zone for all the flame conditions analyzed. The velocity distributions and streamline patterns measured by the present equipment are reasonable and meaningful

  6. 46 CFR 153.908 - Cargo viscosity and melting point information; measuring cargo temperature during discharge...


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo viscosity and melting point information; measuring... Cargo viscosity and melting point information; measuring cargo temperature during discharge: Categories... lading, a written statement of the following: (1) For Category A or B NLS, the cargo's viscosity at 20...

  7. Flat flame burner

    Matsumura, Y.; Mitsudomi, H.


    Osaka Gas Co., Ltd.'s new flat-flame heat-treatment burner offers lower material costs, reduced combustion noise, and elimination of the need for a high-pressure fuel gas to provide a high-velocity combustion burner. The flat-flame burner contains an air-swirling chamber with a flame opening in one side; the wall defining the flame opening has a small thickness around the opening and a flat outer face. This construction causes the combustion gas to be forced out from the flame opening in a spiral direction by the swirling air current within the air chamber; together with the orifice effect of permitting the flame to emanate from a small opening to an unconfined outer space, this helps assure the formation of a flat flame spreading out over a very wide area for very rapid, uniform, and highly efficient heat treatment of an article to be heated. This approach also permits the thickness of the overall device to be reduced. The supply of combustion air in the form of a swirling stream makes it possible to provide a high-velocity combustion burner without using a high-pressure fuel gas, with the advantage of satisfactory mixture of the fuel gas and combustion air and consequently markedly reduced combustion noise.

  8. 46 CFR 154.1810 - Cargo manual.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo manual. 154.1810 Section 154.1810 Shipping COAST... SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Operations § 154.1810 Cargo manual. (a) No person... navigable waters of the United States, or a U.S. flag vessel, unless the vessel has on board a cargo...

  9. 46 CFR 153.907 - Cargo information.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo information. 153.907 Section 153.907 Shipping... Information § 153.907 Cargo information. (a) The master shall ensure that the following information for each... process for the vessel. (b) The master shall make sure that the following information for cargoes...

  10. Determination of high-risk cargo

    Morris, Leo A.; Smith, Douglas E.; Khan, Siraj M.


    The approach and methodology used in the determination of the type of cargo containing concealments of commercial quantities of narcotics such as cocaine and heroin is described. This high-risk cargo enters the United States through border crossings at land, seaports and airports. The volume and variety of cargos make it a complex and challenging task for the U.S. Customs Service.

  11. Cargo-shell and cargo-cargo couplings govern the mechanics of artificially loaded virus-derived cages

    Llauró, Aida; Luque, Daniel; Edwards, Ethan; Trus, Benes L.; Avera, John; Reguera, David; Douglas, Trevor; Pablo, Pedro J. De; Castón, José R.


    Nucleic acids are the natural cargo of viruses and key determinants that affect viral shell stability. In some cases the genome structurally reinforces the shell, whereas in others genome packaging causes internal pressure that can induce destabilization. Although it is possible to pack heterologous cargoes inside virus-derived shells, little is known about the physical determinants of these artificial nanocontainers' stability. Atomic force and three-dimensional cryo-electron microscopy provided mechanical and structural information about the physical mechanisms of viral cage stabilization beyond the mere presence/absence of cargos. We analyzed the effects of cargo-shell and cargo-cargo interactions on shell stability after encapsulating two types of proteinaceous payloads. While bound cargo to the inner capsid surface mechanically reinforced the capsid in a structural manner, unbound cargo diffusing freely within the shell cavity pressurized the cages up to ~30 atm due to steric effects. Strong cargo-cargo coupling reduces the resilience of these nanocompartments in ~20% when bound to the shell. Understanding the stability of artificially loaded nanocages will help to design more robust and durable molecular nanocontainers.Nucleic acids are the natural cargo of viruses and key determinants that affect viral shell stability. In some cases the genome structurally reinforces the shell, whereas in others genome packaging causes internal pressure that can induce destabilization. Although it is possible to pack heterologous cargoes inside virus-derived shells, little is known about the physical determinants of these artificial nanocontainers' stability. Atomic force and three-dimensional cryo-electron microscopy provided mechanical and structural information about the physical mechanisms of viral cage stabilization beyond the mere presence/absence of cargos. We analyzed the effects of cargo-shell and cargo-cargo interactions on shell stability after encapsulating two

  12. Launch Pad Flame Trench Refractory Materials

    Calle, Luz M.; Hintze, Paul E.; Parlier, Christopher R.; Bucherl, Cori; Sampson, Jeffrey W.; Curran, Jerome P.; Kolody, Mark; Perusich, Steve; Whitten, Mary


    The launch complexes at NASA's John F. Kennedy Space Center (KSC) are critical support facilities for the successful launch of space-based vehicles. These facilities include a flame trench that bisects the pad at ground level. This trench includes a flame deflector system that consists of an inverted, V-shaped steel structure covered with a high temperature concrete material five inches thick that extends across the center of the flame trench. One side of the "V11 receives and deflects the flames from the orbiter main engines; the opposite side deflects the flames from the solid rocket boosters. There are also two movable deflectors at the top of the trench to provide additional protection to shuttle hardware from the solid rocket booster flames. These facilities are over 40 years old and are experiencing constant deterioration from launch heat/blast effects and environmental exposure. The refractory material currently used in launch pad flame deflectors has become susceptible to failure, resulting in large sections of the material breaking away from the steel base structure and creating high-speed projectiles during launch. These projectiles jeopardize the safety of the launch complex, crew, and vehicle. Post launch inspections have revealed that the number and frequency of repairs, as well as the area and size of the damage, is increasing with the number of launches. The Space Shuttle Program has accepted the extensive ground processing costs for post launch repair of damaged areas and investigations of future launch related failures for the remainder of the program. There currently are no long term solutions available for Constellation Program ground operations to address the poor performance and subsequent failures of the refractory materials. Over the last three years, significant liberation of refractory material in the flame trench and fire bricks along the adjacent trench walls following Space Shuttle launches have resulted in extensive investigations of

  13. Cargo Assured Access to International Space Station

    Smith, David A.


    Boeing's Cargo Assured Access logistics delivery system will provide a means to transport cargo to/from the International Space Station, Low Earth Orbit and the moon using Expendable Launch Vehicles. For Space Station, this capability will reduce cargo resupply backlog during nominal operations (e.g., supplement Shuttle, Progress, ATV and HTV) and augment cargo resupply capability during contingency operations (e.g., Shuttle delay and/or unavailability of International Partner launch or transfer vehicles). This capability can also provide an autonomous means to deliver cargo to lunar orbit, a lunar orbit refueling and work platform, and a contingency crew safe haven in support of NASA's new Exploration Initiative.

  14. Associations between human exposure to polybrominated diphenyl ether flame retardants via diet and indoor dust, and internal dose: A systematic review.

    Bramwell, Lindsay; Glinianaia, Svetlana V; Rankin, Judith; Rose, Martin; Fernandes, Alwyn; Harrad, Stuart; Pless-Mulolli, Tanja


    The aim of this review was to identify and appraise the current international evidence of associations between concentrations of polybrominated diphenyl ethers (PBDEs) in humans and their indoor dusts and food. We systematically searched Medline, Embase, Web of Science and Scopus (up to Jan 2015), using a comprehensive list of keywords, for English-language studies published in peer-reviewed journals. We extracted information on study design, quality, participants, sample collection methods, adjustments for potential confounders and correlations between PBDE concentrations in internal and external matrices. Of 131 potential articles, 17 studies met the inclusion criteria and were included in the narrative synthesis. We concluded that three key factors influenced correlations between external and internal PBDE exposure; half-life of individual congeners in the human body; proximity and interaction between PBDE source and study subject; and time of study relative to phase out of PBDE technical products. Internal dose of Penta-BDE technical mix congeners generally correlated strongly with dust. The exception was BDE-153 which is known to have higher persistence in human tissues. Despite the low bioaccessibility and short half-life of BDE-209, its high loading in dusts gave strong correlations with body burden where measured. Correlations between PBDE concentrations in duplicate diet and body burden were not apparent from the included studies. Whether dust or diet is the primary exposure source for an individual is tied to the loading of PBDE in dust or food items and the amounts ingested. Simple recommendations such as more frequent hand washing may reduce PBDE body burden. PMID:27066981

  15. 46 CFR 32.55-20 - Venting of cargo tanks of tankships constructed on or after July 1, 1951-T/ALL.


    ... relief valve, provided means are supplied for relieving all internal pressure on cargo tanks by fitting.... (4) The vent header shall be fitted with a flame arrester or pressure vacuum relief valve. If a pressure vacuum relief valve is used in the header, means shall be provided for relieving all...

  16. Cargo-shell and cargo-cargo couplings govern the mechanics of artificially loaded virus-derived cages.

    Llauró, Aida; Luque, Daniel; Edwards, Ethan; Trus, Benes L; Avera, John; Reguera, David; Douglas, Trevor; Pablo, Pedro J de; Castón, José R


    Nucleic acids are the natural cargo of viruses and key determinants that affect viral shell stability. In some cases the genome structurally reinforces the shell, whereas in others genome packaging causes internal pressure that can induce destabilization. Although it is possible to pack heterologous cargoes inside virus-derived shells, little is known about the physical determinants of these artificial nanocontainers' stability. Atomic force and three-dimensional cryo-electron microscopy provided mechanical and structural information about the physical mechanisms of viral cage stabilization beyond the mere presence/absence of cargos. We analyzed the effects of cargo-shell and cargo-cargo interactions on shell stability after encapsulating two types of proteinaceous payloads. While bound cargo to the inner capsid surface mechanically reinforced the capsid in a structural manner, unbound cargo diffusing freely within the shell cavity pressurized the cages up to ∼30 atm due to steric effects. Strong cargo-cargo coupling reduces the resilience of these nanocompartments in ∼20% when bound to the shell. Understanding the stability of artificially loaded nanocages will help to design more robust and durable molecular nanocontainers. PMID:27091107

  17. Green channel cargo inspection system

    A radiation detection device was installed in the lanes of a highway toll station, radioactive rays which was collimated emitted through the measured, and arrived the detector. The average density of the fresh agricultural products belonged to Green channel and other prohibited items vary greatly, the absorption of radiation are different between the Green Channel Cargo and other substances. Prior to the experimental group, different standard samples which represent different models and goods were measured, the different standard samples were stored in a computer database. When the trucks get through the Green Channel, the detector will detect the radiation signal and bring to the computer, the computer will process the measured data, and make a conclusion whether the goods are Green Channel cargo. (authors)

  18. NWA Cargo Is Granted Additional Cargo Frequencies to China Four all-cargo frequencies per week granted by U.S. Department of Transportation


    @@ NWA Cargo, the cargo division of Northwest Airlines, will expand its all-cargo freighter service between the United States and China after being awarded four additional frequencies per week by the U.S. Department of Transportation.

  19. Flaming on YouTube

    Moor, Peter J.; Heuvelman, Ard; Verleur, Ria


    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,

  20. 46 CFR 64.89 - Cargo pump unit.


    ... 46 Shipping 2 2010-10-01 2010-10-01 false Cargo pump unit. 64.89 Section 64.89 Shipping COAST... HANDLING SYSTEMS Cargo Handling System § 64.89 Cargo pump unit. (a) A cargo pump unit that fills or...) The cargo pump power unit must be— (1) Diesel; (2) Hydraulic; (3) Pneumatic; or (4) Electric. (c)...



    The Olympic torch relay will spread peace and harmony across the world Two old nations,one shared dream.A symbolic integration of Eastern and Western civi- lizations was realized when a dramatically dressed Greek priestess kindled a specially designed torch for the Beijing Olympics at the ancient stadium in Olympia,Greece.In a flawless ceremony amid sunrays on March 24,High Priestess Maria Nafpliotou lit the Olympic flame with a concave mirror in front of the Hera Temple in Olympia.The flame was then held in a replica of an ancient urn to ignite the first torch for the upcoming Summer Games in

  2. Flame Stretch Analysis in Diffusion Flames with Inert Gas

    Ay Su; Ying-Chieh Liu


    Experimental investigations of impinging flame with fuel mixed with non-reaction gas were conducted.According to the observations of combustion test and temperature measurement, the non-reaction gas might dilute the local concentration of fuel in the diffusion process. The shape of the flame was symmetrical due to the flame stretch force. Results show that the conical flame might be de-structured by the addition of inert gas in pure methane fuel. The impinging flame became shorter and bluer as nitrogen was added to the fuel. The conditions of N2/CH4 equal to 1/2 and 1/1 show a wider plane in the YZ plane. The effect of inert gas overcomes the flame stretch and destroys the symmetrical column flame as well as the cold flow. Nitrogen addition also enhances the diffusion rate and combustion efficiency.

  3. Unlocking the Keys to Vortex/Flame Interactions in Turbulent Gas-Jet Diffusion Flames--Dynamic Behavior Explored on the Space Shuttle

    Stocker, Dennis P.


    Most combustion processes in industrial applications (e.g., furnaces and engines) and in nature (e.g., forest fires) are turbulent. A better understanding of turbulent combustion could lead to improved combustor design, with enhanced efficiency and reduced emissions. Despite its importance, turbulent combustion is poorly understood because of its complexity. The rapidly changing and random behavior of such flames currently prevents detailed analysis, whether experimentally or computationally. However, it is possible to learn about the fundamental behavior of turbulent flames by exploring the controlled interaction of steady laminar flames and artificially induced flow vortices. These interactions are an inherent part of turbulent flames, and understanding them is essential to the characterization of turbulent combustion. Well-controlled and defined experiments of vortex interaction with laminar flames are not possible in normal gravity because of the interference of buoyancy- (i.e., gravity) induced vortices. Therefore, a joint microgravity study was established by researchers from the Science and Technology Development Corp. and the NASA Lewis Research Center. The experimental study culminated in the conduct of the Turbulent Gas-Jet Diffusion Flames (TGDF) Experiment on the STS-87 space shuttle mission in November 1997. The fully automated hardware, shown in photo, was designed and built at Lewis. During the mission, the experiment was housed in a Get Away Special (GAS) canister in the cargo bay.

  4. Flame Radiation Measurements

    Claus, R. W.; Humenik, F. M.; Neely, G. M.


    Spectral and total flame radiation measurements exhibited: (1) that radiant heat flux increases with vision combustor inlet air pressure; (2) the effect of fuel atomization characteristics on radiant heat flux; and (3) that a reduction in fuel hydrogen content produces a significant increase in radiant heat flux primarily at low combustor pressures.

  5. Flame retardant tarpaulin

    Nozaki, Saiji; Takahashi, Yutaka; Uehara, Hiroshi


    A flame retardant tarpaulin is used for protecting equipments upon periodical repairing in places for handling radioactive materials such as a nuclear power plant. It is formed by coating a woven fabric, a knitted fabric or a non-woven fabric with from 100 to 1000% by weight of a composition formed by blending from 3 to 10 parts by weight of red phosphorus and from 7 to 25 parts by weight of melamine sulfate to 100 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of from 8 to 28% by weight. Further, it comprises metal hydroxides such as Mg hydroxide and Al hydroxide. Aids such as plasticizers, stabilizers, lubricants and colorants can optionally be blended so long as they do not inhibit the flame retardant effect. It has an excellent flame retardancy, and does not produce poisonous gases or a great amount of ashes when burnt and discarded. It can be processed with satisfactory dimensional accuracy upon cutting and stitching, and has flame-proofness as specified by the fire laws. (T.M.)

  6. 46 CFR 151.45-6 - Maximum amount of cargo.


    ... temperature corresponding to the vapor pressure of the cargo at the safety relief valve setting. A reduction... required for a cargo vapor pressure equal to the relief valve setting. d L=Density of cargo at the...

  7. Turbulent oxygen flames in type Ia supernovae

    Aspden, Andrew; Bell, J.; Woosley, S.


    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 agains...

  8. 46 CFR 28.885 - Cargo gear.


    ... 46 Shipping 1 2010-10-01 2010-10-01 false Cargo gear. 28.885 Section 28.885 Shipping COAST GUARD... Aleutian Trade Act Vessels § 28.885 Cargo gear. (a) The safe working load (SWL) for the assembled gear... the load the gear is approved to lift, excluding the weight of the gear itself. (b) All wire...

  9. 48 CFR 470.203 - Cargo preference.


    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Cargo preference. 470.203 Section 470.203 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE FOOD ASSISTANCE PROGRAMS COMMODITY ACQUISITIONS 470.203 Cargo preference. An agency having responsibility under this subpart...

  10. Irradiation Effects for the Pulsed Fast Neutron Analysis (PFNA) Cargo Interrogation System

    Slater, C.O.


    At the request of Safety and Ecology Corporation of Tennessee, radiation effects of the proposed Pulsed Fast Neutron Analysis (PFNA) Cargo Interrogation System have been examined. First, fissile cargo were examined to determine if a significant neutron signal would be observable during interrogation. Results indicated that ample multiplication would be seen for near critical bare targets. The water-reflected sphere showed relatively little multiplication. By implication, a fissile target shielded by hydrogenous cargo might not be detectable by neutron interrogation, particularly if reliance is placed on the neutron signal. The cargo may be detectable if use can be made of the ample increase in the photon signal. Second, dose rates were calculated at various locations within and just outside the facility building. These results showed that some dose rates may be higher than the target dose rate of 0.05 mrem/h. However, with limited exposure time, the total dose may be well below the allowed total dose. Lastly, estimates were made of the activation of structures and typical cargo. Most cargo will not be exposed long enough to be activated to levels of concern. On the other hand, portions of the structure may experience buildup of some radionuclides to levels of concern.

  11. Vehicle and cargo inspection system

    Verbinski, Victor V.; Orphan, Victor J.


    Vehicle and Cargo Inspection System (VACIS) is comprised of a 1 Curie 137Cs gamma-ray source in a shield and collimator which produces a fan-shaped beam designed to intercept a vertical array of gama-ray detectors contained in a tower structure. The source and detector modules straddle the vehicle or container being inspected and are mounted on self-propelled trolleys which travel in synchronization along two parallel tracks covering the length of the scanned object. The signals from the gamma-ray detector array are processed and displayed so as to produce a 2D gamma-radiographic image of the object. Testing of the system on a variety of empty and lightly-loaded vehicles and containers has demonstrated the effectiveness of VACIS in detecting hidden contraband. For example, a small sample of cocaine only 1.5 inches thick was readily detected in a container.

  12. Vortex/Flame Interactions in Microgravity Pulsed Jet Diffusion Flames

    Bahadori, M. Y.; Hegde, U.; Stocker, D. P.


    The problem of vortex/flame interaction is of fundamental importance to turbulent combustion. These interactions have been studied in normal gravity. It was found that due to the interactions between the imposed disturbances and buoyancy induced instabilities, several overall length scales dominated the flame. The problem of multiple scales does not exist in microgravity for a pulsed laminar flame, since there are no buoyancy induced instabilities. The absence of buoyant convection therefore provides an environment to study the role of vortices interacting with flames in a controlled manner. There are strong similarities between imposed and naturally occurring perturbations, since both can be described by the same spatial instability theory. Hence, imposing a harmonic disturbance on a microgravity laminar flame creates effects similar to those occurring naturally in transitional/turbulent diffusion flames observed in microgravity. In this study, controlled, large-scale, axisymmetric vortices are imposed on a microgravity laminar diffusion flame. The experimental results and predictions from a numerical model of transient jet diffusion flames are presented and the characteristics of pulsed flame are described.

  13. Photonic flame effect

    Tcherniega, N. V.; Kudryavtseva, A. D.


    We observed new effect which we called photonic flame effect (PFE). Several 3-dimensional photonic crystals (artificial opals) were posed on Cu plate at the temperature of liquid nitrogen (77K). Typical distance between them was 1-5 centimeters. Long-continued optical luminescence was excited in one of them by the ruby laser pulse. Analogous visible luminescence manifesting time delay appeared in other samples of the crystals. Experiments were realized for opal crystals and for nanocomposites...

  14. When the flame dies

    Hughes, Ed; Morris, R


    When the flame dies Composer - Ed Hughes Librettist - Roger Morris Video - Will Reynolds & Poppy Burton-Morgan With the voices of Andrew McIntosh (baritone); Lucy Williams (mezzo); Peter Kirk (tenor); Emily Phillips (soprano); Ben Williamson (counter-tenor); also video artist Loren O'Dair. Ensemble - The New Music Players Advisers: Tim Hopkins and David Chandler (Professor of Photography, University of Plymouth). Duration: 70 minutes The unnamed Poet, protagonist of the drama, dreams of the U...

  15. Characterization of organophosphorus flame retardants' sorption on building materials and consumer products

    Better understanding the transport mechanisms of organophosphorus flame-retardants (OPFRs) in the residential environment is important to more accurately estimate their indoor exposure and develop risk management strategies that protect human health. This study describes an impro...

  16. Flame Imaging for Safety Surveillance

    Fukuchi, Tetsuo

    Flame detection is important for prevention of spreading of accidental fires. When combustible gas is ignited under daylight conditions, the flame is often difficult to detect by conventional imaging because of the high background radiation. The flame can be visualized by selectively detecting the emission of the OH radical, which is present in hydrocarbon or hydrogen flames. By detecting the OH radical emission in the solar blind region of wavelength below 290 nm, the background radiation can be effectively eliminated. In this study, an experimental device for visualization of flame at wavelength 285 nm was constructed. A combination of two narrowband interference filters was found to be sufficient to eliminate background radiation and selectively image the OH emission. The device could detect butane burner flame under daylight conditions.

  17. Dynamics of unconfined spherical flames

    Leblanc, Louis; Dennis, Kadeem; Zhe,; Liang,; Radulescu, Matei I


    Using the soap bubble technique, we visualize the dynamics of unconfined hydrogen-air flames using high speed schlieren video. We show that for sufficiently weak mixtures, i.e., low flame speeds, buoyancy effects become important. Flame balls of a critical dimension begin to rise. The experiments are found in very good agreement with the scaling laws proposed by Zingale and Dursi. We report the results in a fluid dynamics video.

  18. 46 CFR 105.25-10 - Cargo pumping installation.


    ... 46 Shipping 4 2010-10-01 2010-10-01 false Cargo pumping installation. 105.25-10 Section 105.25-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS... Installed Below Decks § 105.25-10 Cargo pumping installation. (a) Cargo pumps shall not be installed in...

  19. 46 CFR 154.412 - Cargo tank corrosion allowance.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo tank corrosion allowance. 154.412 Section 154.412... Containment Systems § 154.412 Cargo tank corrosion allowance. A cargo tank must be designed with a corrosion...) carries a cargo that corrodes the tank material. Note: Corrosion allowance for independent tank type C...

  20. 46 CFR 154.195 - Aluminum cargo tank: Steel enclosure.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Aluminum cargo tank: Steel enclosure. 154.195 Section... Equipment Hull Structure § 154.195 Aluminum cargo tank: Steel enclosure. (a) An aluminum cargo tank and its... the aluminum cargo tank must meet the steel structural standards of the American Bureau of...

  1. 46 CFR 154.562 - Cargo hose: Hydrostatic test.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo hose: Hydrostatic test. 154.562 Section 154.562 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Hose § 154.562 Cargo hose: Hydrostatic test. Each cargo hose must pass a hydrostatic pressure test...

  2. 29 CFR 1918.87 - Ship's cargo elevators.


    ... 29 Labor 7 2010-07-01 2010-07-01 false Ship's cargo elevators. 1918.87 Section 1918.87 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR LONGSHORING Handling Cargo § 1918.87 Ship's cargo elevators. (a) Safe working load. The safe working loads of ship's cargo elevators shall be determined and...

  3. 46 CFR 153.977 - Supervision of cargo transfer.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Supervision of cargo transfer. 153.977 Section 153.977 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS... Procedures § 153.977 Supervision of cargo transfer. The person in charge of cargo transfer shall:...

  4. 46 CFR 151.13-5 - Cargo segregation-tanks.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo segregation-tanks. 151.13-5 Section 151.13-5... CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Cargo Segregation § 151.13-5 Cargo segregation—tanks. (a... and list the various degrees of segregation required. Paragraphs and (2) of this section explain...

  5. 46 CFR 154.500 - Cargo and process piping standards.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo and process piping standards. 154.500 Section 154... SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo and Process Piping Systems § 154.500 Cargo and process piping standards. The cargo...

  6. 41 CFR 102-117.140 - What is cargo preference?


    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false What is cargo preference... cargo preference? Cargo preference is the statutory requirement that all, or a portion of all, ocean... the cargo preference laws must be approved by: Department of Transportation Maritime...

  7. Continuous Diffusion Flames and Flame Streets in Micro-Channels

    Mohan, Shikhar; Matalon, Moshe


    Experiments of non-premixed combustion in micro-channels have shown different modes of burning. Normally, a flame is established along, or near the axis of a channel that spreads the entire mixing layer and separates a region of fuel but no oxidizer from a region with only oxidizer. Often, however, a periodic sequence of extinction and reignition events, termed collectively as ``flame streets'', are observed. They constitute a series of diffusion flames, each with a tribrachial leading edge stabilized along the channel. This work focuses on understanding the underlying mechanism responsible for these distinct observations. Numerical simulations were conducted in the thermo-diffusive limit in order to study the effects of confinement and heat loss on non-premixed flames in three-dimensional micro-channels with low aspect ratios. The three dimensionality of the channel was captured qualitatively through a systematic asymptotic analysis that led to a two dimensional problem with an effective parameter representing heat losses in the vertical direction. There exist three key flame regimes: (1) a stable continuous diffusion flame, (2) an unsteady flame, and (3) a stable ``flame street'' the transition between regimes demarcated primarily by Reynolds and Nusselt numbers.

  8. System for inspection of stacked cargo containers

    Derenzo, Stephen


    The present invention relates to a system for inspection of stacked cargo containers. One embodiment of the invention generally comprises a plurality of stacked cargo containers arranged in rows or tiers, each container having a top, a bottom a first side, a second side, a front end, and a back end; a plurality of spacers arranged in rows or tiers; one or more mobile inspection devices for inspecting the cargo containers, wherein the one or more inspection devices are removeably disposed within the spacers, the inspection means configured to move through the spacers to detect radiation within the containers. The invented system can also be configured to inspect the cargo containers for a variety of other potentially hazardous materials including but not limited to explosive and chemical threats.

  9. Design of heavy lift cargo aircraft

    National Aeronautics and Space Administration — This is the bird of the skies of the future. The heavy lift cargo aircraft which is currently being developed by me has twice the payload capacity of an Antonov...

  10. IP-1 Certification of Cargo Containers

    Hagler, Lisle [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    The purpose and scope of this engineering note is to demonstrate that the structural design of the cargo container complies with the IP-1 container requirements of 49 CFR 173.410 as required by CFR 173.411.

  11. Characterizing X-ray Attenuation of Containerized Cargo

    Birrer, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Divin, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Glenn, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martz, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wang, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    X-ray inspection systems can be used to detect radiological and nuclear threats in imported cargo. In order to better understand performance of these systems, the attenuation characteristics of imported cargo need to be determined. This project focused on developing image processing algorithms for segmenting cargo and using x-ray attenuation to quantify equivalent steel thickness to determine cargo density. These algorithms were applied to over 450 cargo radiographs. The results are summarized in this report.

  12. The Moving Flame Experiment

    Stern, Melvin E.


    When a flame is rotated around the outside bottom rim of a cylindrical pan of water initially at rest, D. Fultz has observed that the fluid acquires a net vertical component of angular momentum opposite to the rotation of the heat source. We have repeated this experiment in a cylindrical annulus in order to restrict the radial motions and have found that the same phenomenon occurs. Using a simple model based on the latter experiment we investigate the mechanism by which a fluid can acquire an...

  13. Dynamics and structure of stretched flames

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


    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.

  14. Flame retardant polyphosphazenes

    Paciorek, K. L.; Karle, D. W.; Kratzer, R. H.


    Six polyphosphazene compositions were prepared by reaction of three bis-tertiary phosphines with two phenyl-s-triazine derived diazides. All six polyphosphazenes produced were completely characterized, four of them were furthermore subjected to isothermal gravimetric analysis, smoke density measurements, flammability and oxidative thermal degradation testing. The results of the characterization studies indicate that only low molecular weight oligomers, possibly of a cyclic structure, were obtained in the polymerization reactions. Despite this, however, two of the materials showed no weight loss after 96 hr at 200 C, one did not autoignite at 500 C in air, and all four self extinguished when exposed to a flame as soon as contact between flame and resin was lost. The only toxic decomposition products to be concerned about were found to be hydrogen cyanide and benzene. Under the conditions employed it was proven, however, that the quantities of toxic products are greatly reduced if no ignition takes place, e.g., if thermal decomposition proceeds at a sufficiently low rate.

  15. Indirect estimation of radioactivity in containerized cargo

    Naturally occurring radioactive material in containerized cargo challenges the state of the art in national and international efforts to detect illicit nuclear and radiological material in transported containers. Current systems are being evaluated and new systems envisioned to provide the high probability of detection necessary to thwart potential threats, combined with extremely low nuisance and false alarm rates necessary to maintain the flow of commerce impacted by the enormous volume of commodities imported in shipping containers. Maintaining flow of commerce also means that inspection must be rapid, requiring relatively non-intrusive, indirect measurements of cargo from outside containers to the extent possible. With increasing information content in such measurements, it is natural to ask how the information might be combined to improve detection. Toward this end, we present an approach to estimating isotopic activity of naturally occurring radioactive material in cargo grouped by commodity type, combining container manifest data with radiography and gamma-ray spectroscopy aligned to location along the container. The heart of this approach is our statistical model of gamma-ray counts within peak regions of interest, which captures the effects of background suppression, counting noise, convolution of neighboring cargo contributions, and down-scattered photons to provide estimates of counts due to decay of specific radioisotopes in cargo alone. Coupled to that model, we use a mechanistic model of self-attenuated radiation flux to estimate the isotopic activity within cargo, segmented by location within each container, that produces those counts. We test our approach by applying it to a set of measurements taken at the Port of Seattle in 2006. This approach to synthesizing disparate available data streams and extraction of cargo characteristics, while relying on several simplifying assumptions and approximations, holds the potential to support improvement of

  16. Recent Advances in Flame Tomographyt

    闫勇; 邱天; 卢钢; M.M.Hossain; G.Gilabert; 刘石


    To reduce greenhouse gas emissions from fossil fuel fired power plants,a range of new combustion technologies are being developed or refined,including oxy-fuel combustion,co-firing biomass with coal and fluidized bed combustion.Flame characteristics under such combustion conditions are expected to be different from those in normal air fired combustion processes.Quantified flame characteristics such as temperature distribution,oscillation frequency,and ignition volume play an important part in the optimized design and operation of the environmentally friendly power generation systems.However,it is challenging to obtain such flame characteristics particularly through a three-dimensional and non-intrusive means.Various tomography methods have been proposed to visualize and characterize flames,including passive optical tomography,laser based tomography,and electrical tomography.This paper identifies the challenges in flame tomography and reviews existing techniques for the quantitative characterization of flames.Future trends in flame tomography for industrial applications are discussed.

  17. Premixed flame propagation in vertical tubes

    Kazakov, Kirill A


    Analytical treatment of premixed flame propagation in vertical tubes with smooth walls is given. Using the on-shell flame description, equations describing quasi-steady flame with a small but finite front thickness are obtained and solved numerically. It is found that near the limits of inflammability, solutions describing upward flame propagation come in pairs having close propagation speeds, and that the effect of gravity is to reverse the burnt gas velocity profile generated by the flame. On the basis of these results, a theory of partial flame propagation driven by the gravitational field is developed. A complete explanation is given of the intricate observed behavior of limit flames, including dependence of the inflammability range on the size of the combustion domain, the large distances of partial flame propagation, and the progression of flame extinction. The role of the finite front-thickness effects is discussed in detail. Also, various mechanisms governing flame acceleration in smooth tubes are ide...

  18. Uncertainty Quantification for Cargo Hold Fires

    DeGennaro, Anthony M; Martinelli, Luigi; Rowley, Clarence W


    The purpose of this study is twofold -- first, to introduce the application of high-order discontinuous Galerkin methods to buoyancy-driven cargo hold fire simulations, second, to explore statistical variation in the fluid dynamics of a cargo hold fire given parameterized uncertainty in the fire source location and temperature. Cargo hold fires represent a class of problems that require highly-accurate computational methods to simulate faithfully. Hence, we use an in-house discontinuous Galerkin code to treat these flows. Cargo hold fires also exhibit a large amount of uncertainty with respect to the boundary conditions. Thus, the second aim of this paper is to quantify the resulting uncertainty in the flow, using tools from the uncertainty quantification community to ensure that our efforts require a minimal number of simulations. We expect that the results of this study will provide statistical insight into the effects of fire location and temperature on cargo fires, and also assist in the optimization of f...

  19. X-ray scan detection for cargo integrity

    Valencia, Juan; Miller, Steve


    The increase of terrorism and its global impact has made the determination of the contents of cargo containers a necessity. Existing technology allows non-intrusive inspections to determine the contents of a container rapidly and accurately. However, some cargo shipments are exempt from such inspections. Hence, there is a need for a technology that enables rapid and accurate means of detecting whether such containers were non-intrusively inspected. Non-intrusive inspections are most commonly performed utilizing high powered X-ray equipment. The challenge is creating a device that can detect short duration X-ray scans while maintaining a portable, battery powered, low cost, and easy to use platform. The Pacific Northwest National Laboratory (PNNL) has developed a methodology and prototype device focused on this challenge. The prototype, developed by PNNL, is a battery powered electronic device that continuously measures its X-ray and Gamma exposure, calculates the dose equivalent rate, and makes a determination of whether the device has been exposed to the amount of radiation experienced during an X-ray inspection. Once an inspection is detected, the device will record a timestamp of the event and relay the information to authorized personnel via a visual alert, USB connection, and/or wireless communication. The results of this research demonstrate that PNNL's prototype device can be effective at determining whether a container was scanned by X-ray equipment typically used for cargo container inspections. This paper focuses on laboratory measurements and test results acquired with the PNNL prototype device using several X-ray radiation levels.

  20. Photonuclear-based Detection of Nuclear Smuggling in Cargo Containers

    The Idaho National Engineering and Environmental Laboratory (INEEL) and the Los Alamos National Laboratory (LANL) have performed experiments in La Honda, California and at the Idaho Accelerator Center in Pocatello, Idaho to assess and develop a photonuclear-based detection system for shielded nuclear materials in cargo containers. The detection system, measuring photonuclear-related neutron emissions, is planned for integration with the ARACOR Eagle Cargo Container Inspection System (Sunnyvale, CA). The Eagle Inspection system uses a nominal 6-MeV electron accelerator and operates with safe radiation exposure limits to both container stowaways and to its operators. The INEEL has fabricated custom-built, helium-3-based, neutron detectors for this inspection application and is performing an experimental application assessment. Because the Eagle Inspection system could not be moved to LANL where special nuclear material was available, the response of the Eagle had to be determined indirectly so as to support the development and testing of the detection system. Experiments in California have successfully matched the delayed neutron emission performance of the ARACOR Eagle with that of the transportable INEEL electron accelerator (i.e., the Varitron) and are reported here. A demonstration test is planned at LANL using the Varitron and shielded special nuclear materials within a cargo container. Detector results are providing very useful information regarding the challenges of delayed neutron counting near the photofission threshold energy of 5.5 - 6.0 MeV, are identifying the possible utilization of prompt neutron emissions to allow enhanced signal-to-noise measurements, and are showing the overall benefits of using higher electron beam energies

  1. Photonuclear-based Detection of Nuclear Smuggling in Cargo Containers

    Jones, J. L.; Haskell, K. J.; Hoggan, J. M.; Norman, D. R.; Yoon, W. Y.


    The Idaho National Engineering and Environmental Laboratory (INEEL) and the Los Alamos National Laboratory (LANL) have performed experiments in La Honda, California and at the Idaho Accelerator Center in Pocatello, Idaho to assess and develop a photonuclear-based detection system for shielded nuclear materials in cargo containers. The detection system, measuring photonuclear-related neutron emissions, is planned for integration with the ARACOR Eagle Cargo Container Inspection System (Sunnyvale, CA). The Eagle Inspection system uses a nominal 6-MeV electron accelerator and operates with safe radiation exposure limits to both container stowaways and to its operators. The INEEL has fabricated custom-built, helium-3-based, neutron detectors for this inspection application and is performing an experimental application assessment. Because the Eagle Inspection system could not be moved to LANL where special nuclear material was available, the response of the Eagle had to be determined indirectly so as to support the development and testing of the detection system. Experiments in California have successfully matched the delayed neutron emission performance of the ARACOR Eagle with that of the transportable INEEL electron accelerator (i.e., the Varitron) and are reported here. A demonstration test is planned at LANL using the Varitron and shielded special nuclear materials within a cargo container. Detector results are providing very useful information regarding the challenges of delayed neutron counting near the photofission threshold energy of 5.5 - 6.0 MeV, are identifying the possible utilization of prompt neutron emissions to allow enhanced signal-to-noise measurements, and are showing the overall benefits of using higher electron beam energies.

  2. Flame-coating method and flame-coating device

    The method and the device of the present invention improve the quality and operation efficiency of coating applied to corner portions of under water reactor structural components of a nuclear reactor. Namely, powders for the flame-coating are provided with ferromagnetic property in a step of forming coating films to underwater structural members by an underwater flame-coating method in a nuclear reactor. A flow of plasma arc can be bent by applying magnetic fields to the flame-coating plasma arc. Accordingly, coatings can be applied to corner portions particularly to pad-weld portions among welded members. Further, the flame-coating can be applied while being conformed to the shape of the place where a surface layer is formed, by controlling the extension of the plasma arc by making the shape of the plasma arc irradiated on the surface of a work rectangular, elliptic or linear. (I.S.)

  3. Characterizing Complexity of Containerized Cargo X-ray Images

    Wang, Guangxing [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martz, Harry [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Glenn, Steven [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Divin, Charles [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Birrer, Nat [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    X-ray imaging can be used to inspect cargos imported into the United States. In order to better understand the performance of X-ray inspection systems, the X-ray characteristics (density, complexity) of cargo need to be quantified. In this project, an image complexity measure called integrated power spectral density (IPSD) was studied using both DNDO engineered cargos and stream-of-commerce (SOC) cargos. A joint distribution of cargo density and complexity was obtained. A support vector machine was used to classify the SOC cargos into four categories to estimate the relative fractions.

  4. Flame spraying of polymers

    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

  5. Electrical Aspects of Impinging Flames

    Chien, Yu-Chien

    This dissertation examines the use of electric fields as one mechanism for controlling combustion as flames are partially extinguished when impinging on nearby surfaces. Electrical aspects of flames, specifically, the production of chemi-ions in hydrocarbon flames and the use of convective flows driven by these ions, have been investigated in a wide range of applications in prior work but despite this fairly comprehensive effort to study electrical aspects of combustion, relatively little research has focused on electrical phenomena near flame extinguishment, nor for flames near impingement surfaces. Electrical impinging flames have complex properties under global influences of ion-driven winds and flow field disturbances from the impingement surface. Challenges of measurements when an electric field is applied in the system have limited an understanding of changes to the flame behavior and species concentrations caused by the field. This research initially characterizes the ability of high voltage power supplies to respond on sufficiently short time scales to permit real time electrical flame actuation. The study then characterizes the influence of an electric field on the impinging flame shape, ion current and flow field of the thermal plume associated with the flame. The more significant further examinations can be separated into two parts: 1) the potential for using electric fields to control the release of carbon monoxide (CO) from surface-impinging flames, and 2) an investigation of controlling electrically the heat transfer to a plate on which the flame impinges. Carbon monoxide (CO) results from the incomplete oxidation of hydrocarbon fuels and, while CO can be desirable in some syngas processes, it is usually a dangerous emission from forest fires, gas heaters, gas stoves, or furnaces where insufficient oxygen in the core reaction does not fully oxidize the fuel to carbon dioxide and water. Determining how carbon monoxide is released and how heat transfer

  6. Fluctuation effects in bidirectional cargo transport

    Klein, Sarah; Santen, Ludger


    We discuss a theoretical model for bidirectional cargo transport in biological cells, which is driven by teams of molecular motors and subject to thermal fluctuations. The model describes explicitly the directed motion of the molecular motors on the filament. The motor-cargo coupling is implemented via linear springs. By means of extensive Monte Carlo simulations we show that the model describes the experimentally observed regimes of anomalous diffusion, i.e. subdiffusive behavior at short times followed by superdiffusion at intermediate times. The model results indicate that subdiffuse regime is induced by thermal fluctuations while the superdiffusive motion is generated by correlations of the motors' activity. We also tested the efficiency of bidirectional cargo transport in crowded areas by measuring its ability to pass barriers with increased viscosity. Our results show a remarkable gain of efficiency for high viscosities.

  7. Flame stabilization by a plasma driven radical jet in a high speed flow

    Choi, Woong-Sik

    In current afterburners combustion is stabilized by the high temperature, recirculating region behind bluff body flame holders, such as V-gutters. Blocking the high speed flow with bluff bodies causes a significant pressure drop, and heating the flame holder by the hot combustion product causes a thermal signature, which is a critical problem in a military jet. To reduce these problems, ignition methods using a high frequency (HF) spark discharge, or a radical jet generator (RJG) were developed. The HF discharge ignited and stabilized a flame successfully in a premixed methane-air flow. The electrical power consumption was very small compared to the combustion heat release, as long as the operating velocity was relatively low. However, a theoretical study showed that the ratio of the electrical power consumption to the heat generation by the stabilized flame increases rapidly with increasing flow velocity. For flame stabilization in a high velocity flow, the developed RJG showed much better performance than direct exposure to a plasma. The present study investigated the characteristics of a radical jet produced in a RJG and injected into a main combustor. The limits of flame stabilization by this jet was measured experimentally, and compared to those of bluff body flame holders. The flame holding performance of the radical jet was also experimentally compared to that of a thermal jet. The effect of radicals on flame stabilization was examined using CHEMKIN, and the limit of flame stabilization by the radical jet was estimated for a simple flow configuration using an approximate solution. The results suggest that the reduction of local spontaneous ignition delay time by active species in the radical jet and the longer length of a typical radical jet compared to the dimension of the recirculation zone behind a bluff body increases the maximum velocity at which a flame can be stabilized.

  8. Institute Cargo Clauses : Nova verzija 2009.

    Lovrić, Ivana


    Institute Cargo Clauses, 2009. znače izmijenjene i dopunjene Institute Cargo Clauses iz 1982. Osnovni razlozi za reviziju prijašnjih uvjeta leže u pojavi novih rizika, potrebi da se uvjeti kargo osiguranja prilagode promjenama u suvremenom transportnom sustavu te jezično i terminološki osuvremene. Novi uvjeti donose niz rješenja koja znače modernizaciju u odnosu na rješenja Marine Insurance Acta iz 1906. Redaktori novih uvjeta vodili su računa i o tome da pojedine odredbe budu jasnije form...

  9. Trajanje osiguranja prema Institute Cargo Clauses (2009.)

    Petrinović, Ranka; Lovrić, Ivana


    Institute Cargo Clauses iz 2009. zapravo su izmjene i dopune Institute Cargo Clauses iz 1982. Osnovni su razlozi za reviziju prijašnjih uvjeta u pojavi novih rizika, potrebi da se uvjeti kargo-osiguranja prilagode promjenama u suvremenome transportnom sustavu te jezično i terminološki osuvremene. Novi uvjeti donose više rješenja koja znače modernizaciju u usporedbi s onima u Marine Insurance Acta iz 1906., pa se prezentiraju kao klauzule za novo tisućljeće. Među bitnim promjenama koje donose ...

  10. 46 CFR 105.20-3 - Cargo tanks.


    ... VESSELS DISPENSING PETROLEUM PRODUCTS Specific Requirements-Cargo Tanks § 105.20-3 Cargo tanks. (a... subjected, except that in no case shall the thickness of the shell or head be less than that specified...

  11. On the theory of turbulent flame velocity

    Bychkov, Vitaly; Petchenko, Arkady; 10.1080/00102200600808466


    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 larger than the cut off wavelength of the instability. The developed theory is used to analyse recent experiments on turbulent flames propagating in tubes. It is demonstrated that most of the flame velocity increase measured experimentally is provided by the large scale effects like the flame instability, and not by the small-scale external turbulence.

  12. Coupling of wrinkled laminar flames with gravity

    Bedat, Benoit; Kostiuk, Larry W.; Cheng, Robert K.


    The overall objective of our research is to understand flame-gravity coupling processes in laminar and low turbulent Reynolds number, Re(sub l), premixed flames (i.e. wrinkled- laminar flames). The approach we have developed is to compare the flowfields and mean flame properties under different gravitational orientations. Key to our study is the investigation of microgravity (mu g) flames. These mu g experiments provide vital information to reconcile the differences between flames in normal gravity (+g, flame pointing upward) and reverse gravity (-g, flame pointing downwards). Traditionally, gravity effects are assumed to be insignificant or circumvented in the laboratory, therefore, not much is available in the literature on the behavior of -g flames.

  13. 49 CFR 172.448 - CARGO AIRCRAFT ONLY label.


    ... 49 Transportation 2 2010-10-01 2010-10-01 false CARGO AIRCRAFT ONLY label. 172.448 Section 172.448... SECURITY PLANS Labeling § 172.448 CARGO AIRCRAFT ONLY label. (a) Except for size and color, the CARGO AIRCRAFT ONLY label must be as follows: ER14JA09.001 (b) The CARGO AIRCRAFT ONLY label must be black on...

  14. Visual Analysis Special Report Technical Appendix, Operation of Flaming Gorge Dam Final Environmental Impact Statement

    Hanchett, Brent


    This report addresses the scenic resources surrounding Flaming Gorge Reservoir and the Green River Corridor. The focus is on potential visual impacts to changes in shoreline exposure resulting from fluctuating ongoing water levels and downstream water flows. Discussion will include scenic resources on the Flaming Gorge National Recreation Area (NRA) and the Green River Corridor. The U.S. Department of Agriculture Forest Service (USDA Forest Service) and Bureau of Land Management (BLM) have de...

  15. 46 CFR 151.25-2 - Cargo handling space.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo handling space. 151.25-2 Section 151.25-2 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Environmental Control § 151.25-2 Cargo handling space. Pump rooms, compressor rooms, refrigeration rooms, heating rooms, instrument rooms or other closed...

  16. 33 CFR 157.23 - Cargo and ballast system information.


    ... CARRYING OIL IN BULK Design, Equipment, and Installation § 157.23 Cargo and ballast system information. (a... automatic and manual operation of the cargo and ballast system in the vessel. (b) The format and information... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Cargo and ballast...

  17. 46 CFR 153.440 - Cargo temperature sensors.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo temperature sensors. 153.440 Section 153.440 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS... Temperature Control Systems § 153.440 Cargo temperature sensors. (a) Except as prescribed in paragraph (c)...

  18. 48 CFR 52.228-9 - Cargo Insurance.


    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Cargo Insurance. 52.228-9... Insurance. As prescribed in 28.313(a), insert the following clause: Cargo Insurance (MAY 1999) (a) The..., cargo insurance of $_____ per vehicle to cover the value of property on each vehicle and of $_____...

  19. 46 CFR 151.20-20 - Cargo transfer methods.


    ... 90 percent of the set pressure of the cargo tank safety relief valve. The pressurizing line shall be... shall be fitted with a safety relief valve set to lift at a pressure no higher than 80 percent of the cargo tank safety relief valve setting. (d) When cargo vapors are flammable, combustible or toxic,...


    N. Ponomariova; Stoliar, T.


    The matter concerning customs logistics being an integral part of cargo delivery logistics range of international routes has been considered. The aim of functioning of cargo customs handling process has been determined. The application of Petri network theory for the purpose of customs cargo handling model development has been proved.

  1. Development of 60Co cargo train inspection system

    The author introduces the research and development of 60Co cargo train inspection system. With the use of radiography principle, every car image is acquired when the cargo train runs through the inspection channel. It is evaluated whether the cargo in car matches the corresponding customs declaration information with digital image processing techniques. The system has been installed in railway port at Manzhouli Customs

  2. Molecular approach to intracellular cargo transport

    Yildiz, Ahmet


    Landmark discoveries in the study of cytoplasmic motors have been made through advances in single molecule biophysics and detailed mechanistic models exist for kinesin and dynein. However, the function of motors in physiological conditions has not been carefully tested. In cells, more than few dyneins can attach to the same cargo and interact with the opposite polarity motors of kinesin. To study the molecular crosstalk between the motors, we have used intraflagellar transport (IFT) in Chlamydomonas reinhardtii as a model system. Ultrahigh spatio-temporal tracking of single cargo movement showed that IFT particles move for long distances unidirectionally with 8 nm increments, agreeing with measured step sizes of kinesin and dynein. To measure how many motors transport each cargo, we have linked large polystyrene beads to internal IFT particles through a transmembrane protein. Force measurements indicated that, on average, 3-4 motors transport cargoes in each direction. The results showed that IFT motors are tightly coordinated and might be involved in recycling each other to the appropriate end of the flagellum.

  3. 78 FR 68784 - Cargo Securing Manuals


    ... regarding our public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316). D. Public... Practice for Cargo Stowage and Securing E.O. Executive Order FR Federal Register IMO International Maritime.... vessels or for foreign vessels operating in U.S. waters. In a notice (64 FR 1648; Jan. 11,...

  4. 46 CFR 64.91 - Relief valve for the cargo pump discharge.


    ... 46 Shipping 2 2010-10-01 2010-10-01 false Relief valve for the cargo pump discharge. 64.91 Section... PORTABLE TANKS AND CARGO HANDLING SYSTEMS Cargo Handling System § 64.91 Relief valve for the cargo pump discharge. The cargo pump discharge must have a relief valve that is— (a) Fitted between the cargo...

  5. Discharging Part of LNG Liquid Cargo Handling Simulator

    Zhen-Zhou Yang


    Full Text Available With the development of the national economy, it is important to develop LNG (Liquefied Natural Gas liquid cargo handling simulator. In this paper, the discharging part of Liquid Cargo Handling Simulator of LNG Carriers is developed by Visual Basic. The system includes 5 major forms and 3 mathematical models such as cargo pump model, the pressure and temperature model of the LNG vapour in the cargo tank and the liquid level model. The system can complete the unloading task. The system has become a preliminary model of LNG liquid cargo handlings simulator training.

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

    Chung, Yong Ho


    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.

  7. Aviation System Analysis Capability Air Carrier Investment Model-Cargo

    Johnson, Jesse; Santmire, Tara


    The purpose of the Aviation System Analysis Capability (ASAC) Air Cargo Investment Model-Cargo (ACIMC), is to examine the economic effects of technology investment on the air cargo market, particularly the market for new cargo aircraft. To do so, we have built an econometrically based model designed to operate like the ACIM. Two main drivers account for virtually all of the demand: the growth rate of the Gross Domestic Product (GDP) and changes in the fare yield (which is a proxy of the price charged or fare). These differences arise from a combination of the nature of air cargo demand and the peculiarities of the air cargo market. The net effect of these two factors are that sales of new cargo aircraft are much less sensitive to either increases in GDP or changes in the costs of labor, capital, fuel, materials, and energy associated with the production of new cargo aircraft than the sales of new passenger aircraft. This in conjunction with the relatively small size of the cargo aircraft market means technology improvements to the cargo aircraft will do relatively very little to spur increased sales of new cargo aircraft.

  8. Premixed Turbulent Flame Propagation in Microgravity

    Menon, S.; Disseau, M.; Chakravarthy, V. K.; Jagoda, J.


    Papers included address the following topics: (1) Turbulent premixed flame propagation in microgravity; (2) The effect of gravity on turbulent premixed flame propagation - a preliminary cold flow study; and (3) Characteristics of a subgrid model for turbulent premixed combustion.

  9. Displacement speeds in turbulent premixed flame simulations

    Day, Marcus S.; Shepherd, Ian G.; Bell, J.; Grcar, Joseph F.; Lijewski, Michael J.


    The theory of turbulent premixed flames is based on acharacterization of the flame as a discontinuous surface propagatingthrough the fluid. The displacement speed, defined as the local speed ofthe flame front normal to itself, relative to the unburned fluid,provides one characterization of the burning velocity. In this paper, weintroduce a geometric approach to computing displacement speed anddiscuss the efficacy of the displacement speed for characterizing aturbulent flame.

  10. Self-turbulizing flame fronts

    Clavin, P.; Searby, G.

    A heuristic derivation of a flame front model is presented that takes into account the effects of gravity, nonlinear effects introduced by advection of the front, and gradients in the tangential component of the flow. A local equation is defined to relate the normal flame speed to the upstream gas flow characteristics. Jump conditions are obtained from an asymptotic analysis of the local structure of the wrinkled flame in order to address the hydrodynamic problem possed by the front being treated as a free boundary between fresh and burnt gases. The expression for the jump conditions is defined in Fourier space. The model extends the equations defined in Fourier space. The model extends the equations defined by Sivashinsky (1977) to cover the effects of gas expansion.

  11. Model flames in a hydrostatic atmosphere

    Caceres Calleja, Alvaro

    A model flame system based on the advection-diffusion-reaction method is defined and used to numerically study the problem of a flame propagating up an initially hydrostatic atmosphere, in 2-D. We identify and characterize the flame's steady states over a range of parameters, in the case where the gravitational scale height is much greater than the size of the flame, which itself is much greater than the flame's laminar width. We observe both laminar and turbulent steady flames and verify that, for strong enough gravity G, the turbulent flame speed is independent of the laminar flame speed and scales like the square root of GL, where L is the size of our domain. As this scaling law is commonly used to implement flame subgrid models, one of the aims of this thesis is to understand its robustness. We describe the flame geometry and discuss its relationship with the flame speed. The flow statistics inside turbulent flames are measured and found to be gaussian and isotropic, corresponding to strong mixing.

  12. Flame assisted synthesis of catalytic ceramic membranes

    Johansen, Johnny; Mosleh, Majid; Johannessen, Tue;


    Membranes consisting of one or more metal oxides can be synthesized by flame pyrolysis. The general principle behind flame pyrolysis is the decomposition and oxidation of evaporated organo-metallic precursors in a flame, thereby forming metal oxide monomers. Because of the extreme supersaturation...

  13. Premixed flame propagation in vertical tubes

    Kazakov, Kirill A.


    Analytical treatment of the premixed flame propagation in vertical tubes with smooth walls is given. Using the on-shell flame description, equations for a quasi-steady flame with a small but finite front thickness are obtained and solved numerically. It is found that near the limits of inflammability, solutions describing upward flame propagation come in pairs having close propagation speeds and that the effect of gravity is to reverse the burnt gas velocity profile generated by the flame. On the basis of these results, a theory of partial flame propagation driven by a strong gravitational field is developed. A complete explanation is given of the intricate observed behavior of limit flames, including dependence of the inflammability range on the size of the combustion domain, the large distances of partial flame propagation, and the progression of flame extinction. The role of the finite front-thickness effects is discussed in detail. Also, various mechanisms governing flame acceleration in smooth tubes are identified. Acceleration of methane-air flames in open tubes is shown to be a combined effect of the hydrostatic pressure difference produced by the ambient cold air and the difference of dynamic gas pressure at the tube ends. On the other hand, a strong spontaneous acceleration of the fast methane-oxygen flames at the initial stage of their evolution in open-closed tubes is conditioned by metastability of the quasi-steady propagation regimes. An extensive comparison of the obtained results with the experimental data is made.

  14. Temperature measurement of axi- symmetric butane diffusion flame under the influence of upward decreasing gradient magnetic field using digital holographic interferometry

    Kumar, Varun; Kumar, Manoj; Shakher, Chandra


    In this paper, digital holographic interferometry (DHI) is implemented to investigate the effect of upward decreasing gradient magnetic field on the temperature and temperature profile of diffusion flame created by butane torch burner. In the experiment double exposure digital holographic interferometry is used to calculate the temperature distribution inside the flame. First a digital hologram is recorded in the absence of flame and second hologram is recorded in the presence of flame. Phases in two different states of air (i.e. in absence of flame and presence of flame) are reconstructed individually by numerical method. The phase difference map is obtained by subtracting the reconstructed phase of air in presence and absence of flame. Refractive index inside the flame is obtained from the axi-symmetric phase difference data using the Abel inversion integral. Temperature distribution inside the flame is calculated from the refractive index data using Lorentz - Lorentz equation. Experiment is conducted on a diffusion flame created by butane torch burner in the absence of magnetic field and in presence of upward decreasing gradient magnetic field. Experimental investigations reveal that the maximum temperature inside the flame increases under the influence of upward decreasing magnetic field.

  15. Experimental characterization of methane inverse diffusion flame

    Elbaz, Ayman M.


    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

  16. Detection of Neutron Sources in Cargo Containers

    Katz, J. I.


    We investigate the problem of detecting the presence of clandestine neutron sources, such as would be produced by nuclear weapons containing plutonium, within cargo containers. Small, simple and economical semiconductor photodiode detectors affixed to the outsides of containers are capable of producing statistically robust detections of unshielded sources when their output is integrated over the durations of ocean voyages. It is possible to shield such sources with thick layers of neutron-abs...

  17. Design of a spanloader cargo aircraft


    With a growing demand for fast international freight service, the slow-moving cargo ships currently in use will soon find a substantial portion of their clients looking elsewhere. One candidate for filling this expected gap in the freight market is a span-loading aircraft (or 'flying wing') capable of long-range operation with extremely large payloads. This report summarizes the design features of an aircraft capable of fulfilling a long-haul, high-capacity cargo mission. The spanloader seeks to gain advantage over conventional aircraft by eliminating the aircraft fuselage and thus reducing empty weight. The primary disadvantage of this configuration is that the cargo-containing wing tends to be thick, thus posing a challenge to the airfoil designer. It also suffers from stability and control problems not encountered by conventional aircraft. The result is an interesting, challenging exercise in unconventional design. The report that follows is a student written synopsis of an effort judged to be the best of eight designs developed during the year 1988-1989.

  18. KSC Launch Pad Flame Trench Environment Assessment

    Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Curran, Jerome P.; Kolody, Mark R.; Sampson, Jeffrey W.


    This report summarizes conditions in the Launch Complex 39 (LC-39) flame trenches during a Space Shuttle Launch, as they have been measured to date. Instrumentation of the flame trench has been carried out by NASA and United Space Alliance for four Shuttle launches. Measurements in the flame trench are planned to continue for the duration of the Shuttle Program. The assessment of the launch environment is intended to provide guidance in selecting appropriate test methods for refractory materials used in the flame trench and to provide data used to improve models of the launch environment in the flame trench.

  19. An Improved Calcium Flame Test.

    Pearson, Robert S.


    Indicates that the true red color of calcium can be obtained (using the procedure described by Sorm and Logowski) if the calcium ion solution is mixed with an equal volume of saturated ammonium bromide solution. Suggestions for flame tests of other elements are also noted. (JN)

  20. The VLT FLAMES Tarantula Survey

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


    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 th

  1. Improvements of natural rubber for flame resistance

    Orasa Patarapaiboolchai


    Full Text Available The present invention provides a process for treating natural rubber to increase its flame retardant capability. Theprocess comprises a mixture of a natural rubber with, (a halogenated free flame retardant agent (zinc hydroxystannate;STORFLAM ZHS and (b halogenated flame retardant agent (decabromodiphenyl; Great Lake DE-83R and chlorinatedparaffins; Plastoil 152 and another material like antimony trioxide and aluminium hydroxide in appropriate amount, with ratio of halogenated flame retardant agent: antimony trioxide 3:1. In the resulting product with halogen flame retardant showed a more efficient flame retardant property than halogen free flame retardant, i.e. brominated flame retardant provide higher efficiency than chlorinated and ZHS, respectively. The minimum requirement ratio for being flame retardant of antimonytrioxide: brominated or chlorinated agent is 7:21 or 10:30 phr while aluminium hydroxide: ZHS is 10: 150 phr. It was found thatburning rate was zero for brominated and chlorinated agent used but not for zinc hydroxyl stannate system. Average time of burning (ATB was 135, 118 and 41 second for brominated, chlorinated and ZHS flame retardant, respectively. Average extent of burning (AEB was 24, 19 and 14 millimeters, respectively. An advantage of this invention is that chemicals (antimony trioxide and either brominated or chlorinated agent added to natural rubber have the effect of rendering the natural rubber flame-resistant like synthetic rubbers, chloroprene.

  2. Flame Reconstruction Using Synthetic Aperture Imaging

    Murray, Preston; Tree, Dale; Truscott, Tadd


    Flames can be formed by burning methane (CH4). When oxygen is scarce, carbon particles nucleate into solid particles called soot. These particles emit photons, making the flame yellow. Later, methane is pre-mixed with air forming a blue flame; burning more efficiently, providing less soot and light. Imaging flames and knowing their temperature are vital to maximizing efficiency and validating numerical models. Most temperature probes disrupt the flame and create differences leading to an inaccurate measurement of the flame temperature. We seek to image the flame in three dimensions using synthetic aperture imaging. This technique has already successfully measured velocity fields of a vortex ring [1]. Synthetic aperture imaging is a technique that views one scene from multiple cameras set at different angles, allowing some cameras to view objects that are obscured by others. As the resulting images are overlapped different depths of the scene come into and out of focus, known as focal planes, similar to tomogr...

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

    Uranakara, Harshavardhana A.


    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.

  4. Determination of Fire Enviroment in Stacked Cargo Containers with Radioactive Materials Packages

    Arviso, M.; Bobbe, J.G.; Dukart, R.D.; Koski, J.A.


    Results from a Fire Test with a three-by-three stack of standard 6 m long International Standards Organization shipping containers containing combustible fuels and empty radioactive materials packages are reported and discussed. The stack is intended to simulate fire conditions that could occur during on-deck stowage on container cargo ships. The fire is initated by locating the container stack adjacent to a 9.8 x 6 m pool fire. Temperatures of both cargoes (empty and simulated radioactive materials packages) and containers are recorded and reported. Observations on the duration, intensity and spread of the fire are discussed. Based on the results, models for simulation of fire exposure of radioactive materials packages in such fires are suggested.

  5. Cargo transportation by two species of motor protein

    Zhang, Yunxin


    The cargo motion in living cells transported by two species of motor protein with different intrinsic directionality is discussed in this study. Similar to single motor movement, cargo steps forward and backward along microtubule stochastically. Recent experiments found that, cargo transportation by two motor species has a memory, it does not change its direction as frequently as expected, which means that its forward and backward step rates depends on its previous motion trajectory. By assuming cargo has only the least memory, i.e. its step direction depends only on the direction of its last step, two cases of cargo motion are detailed analyzed in this study: {\\bf (I)} cargo motion under constant external load; and {\\bf (II)} cargo motion in one fixed optical trap. Due to the existence of memory, for the first case, cargo can keep moving in the same direction for a long distance. For the second case, the cargo will oscillate in the trap. The oscillation period decreases and the oscillation amplitude increase...

  6. Flame extinction of oxy-syngas nonpremixed jet flames

    Ranga Dinesh, K. K. J.; Luo, K.H.; van Oijen, J. A.


    Interest in carbon capture relevant to syngas based oxy-fuel combustion has inspired an extension of the high-resolution direct numerical simulation (DNS) to investigate the comprehensive nature of oxy-syngas combustion. The current research was motivated by two observations: (1) the local flame extinction of CO2-diluted oxy-syngas combustion has not been fully understood; (2) there is a lack of high resolution numerical data to gain new physical insights and to facilitate model development f...


    A. M. Okorokov


    Full Text Available Purpose. Making the qualitative administrative decisions defining strategy and tactics of transport cargo complexes development, and also its subsystems, is possible only in the presence of flexible optimization model. This model has to consider multiparametricity and multicriteriality of the given task, uncertainty and vagueness of input information, and also to provide process automation of searching the best parameters of the given production facility. The purpose of the research is to develop procedures for the strategic management of complex with view of the most important factors and their stochastic nature, which will execute the improvement of technical equipment of TCC. Methodology. The problem of strategic management is based on solving the complex of issues of the optimal number of shunting locomotives, optimal processing capability of handling the front and rational capacity of warehouses. The problem is solved on the basis of the proposed optimality criterion – the specific set of profit per unit of capital assets of freight industry. The listed problems are solved using simulation modeling of the freight industry. Findings. The use of developed procedure allows one to improve the technical equipment of the freight stations and complexes. Originality. For the first time it was developed the procedure of strategic management of development. This procedure allows taking into account the probabilistic nature of demand for services of transport freight complexes and technological processes of client services on the complex stations. The proposed procedure can be applied during when planning the investments in the creation of transport freight complexes. Practical value. Use as a basic tool of simulation models of complex cargo operation allows estimating the effectiveness of the capital investments, the level of operating costs, as well as the quality of meeting the demands of potential customers in transportations at the stage of

  8. Fully Modulated Turbulent Diffusion Flames in Microgravity*

    Sangras, Ravikiran; Hermanson, James C.; Johari, Hamid; Stocker, Dennis P.; Hegde, Uday G.


    Fully modulated, turbulent diffusion flames are studied in microgravity in 2.2 s drop-tower tests with a co-flow combustor. The fuel consists of pure ethylene or a 50/50 mixture with nitrogen; the oxidizer is either normal air or up to 40% oxygen in nitrogen. A fast solenoid valve is used to fully modulate (completely shut off) the fuel flow. The injection times range from 5 to 400 ms with a duty-cycle of 0.1 - 0.5. The fuel nozzle is 2 mm in diameter with a jet Reynolds number of 5000. The shortest injection times yield compact puffs with a mean flame length as little as 20% of that of the steady-state flame. The reduction in flame length appears to be somewhat greater in microgravity than in normal gravity. As the injection time increases, elongated flames result with a mean flame length comparable to that of a steady flame. The injection time for which the steady-state flame length is approached is shorter for lower air/fuel ratios. For a given duty-cycle, the separation between puffs is greater in microgravity than in normal gravity. For compact puffs, increasing the duty-cycle appears to increase the flame length more in microgravity than in normal gravity. The microgravity flame puffs do not exhibit the vortex-ring-like structure seen in normal gravity.

  9. Effects of Buoyancy on Lean Premixed V-Flames Part I: Laminar and Turblent Flame Structure

    Cheng, Robert K.; Bedat, Benoit; Kostiuk, Larry W.


    Laser schlieren and planar laser-induced fluorescence techniques have been used to investigate laminar and turbulent v-flames in +g, -g, and micro g under flow conditions that span the regimes of momentum domination (Ri buoyancy domination (Ri > 0.1). Overall flame features shown by schlieren indicate that buoyancy dominates the entire flow field for conditions close to Ri = 1. With decreasing Ri, buoyancy effects are observed only in the far-field regions. Analyses of the mean flame angles demonstrate that laminar and turbulent flames do not have similar responses to buoyancy. Difference in the laminar +g and -g flame angles decrease with Ri (i.e., increasing Re) and converge to the microgravity flame angle at the momentum limit (Ri - 0). This is consistent with the notion that the effects of buoyancy diminish with increasing flow momentum. The +g and -g turbulent flame angles, however, do not converge at Ri = 0. As shown by OH-PLIF images, the inconsistency in +g and -g turbulent flame angles is associated with the differences in flame wrinkles. Turbulent flame wrinkles evolve more slowly in +g than in -g. The difference in flame wrinkle structures, however, cannot be explained in terms of buoyancy effects on flame instability mechanisms. It seems to be associated with the field effects of buoyancy that stretches the turbulent flame brushes in +g and compresses the flame brush in -g. Flame wrinkling offers a mechanism through which the flame responds to the field effects of buoyancy despite increasing flow momentum. These observations point to the need to include both upstream and downstream contributions in theoretical analysis of flame turbulence interactions.

  10. NLS cargo transfer vehicle propulsion system

    Hearn, Hank C.; Langford, G. K.


    The propulsion system of the Cargo Transfer Vehicle is designed to meet a wide range of requirements associated with the National Launch System (NLS) resupply function for Space Station Freedom. It provides both orbit adjustment and precise vehicle control capability, and is compatible with close proximity operation at the space station as well as return on the shuttle for ground refurbishment and reuse. Preliminary trade studies have resulted in designing and sizing an integrated bipropellant system using monomethyl hydrazine and nitrogen tetroxide. Design and analysis activities are continuing, and the design will evolve and mature as part of the NLS program.

  11. Refractory Materials for Flame Deflector Protection System Corrosion Control: Coatings Systems Literature Survey

    Calle, Luz M.; Hintze, Paul E.; Parlier, Christopher R.; Sampson, Jeffrey W.; Coffman, Brekke E.; Coffman, Brekke E.; Curran, Jerome P.; Kolody, Mark R.; Whitten, Mary; Perisich, Steven; Trejo, David


    When space vehicles are launched, extreme heat, exhaust, and chemicals are produced and these form a very aggressive exposure environment at the launch complex. The facilities in the launch complex are exposed to this aggressive environment. The vehicle exhaust directly impacts the flame deflectors, making these systems very susceptible to high wear and potential failure. A project was formulated to develop or identify new materials or systems such that the wear and/or damage to the flame deflector system, as a result of the severe environmental exposure conditions during launches, can be mitigated. This report provides a survey of potential protective coatings for the refractory concrete lining on the steel base structure on the flame deflectors at Kennedy Space Center (KSC).

  12. Flame Propagation Through Concentration Gradient

    JunyaIINO; MitsuakiTANABE; 等


    The experiment was carried out in homogeneous propane-air mixture and in several concentration gradient of mixture.Igniter is put on the upper side of the combustion chamber,In concentration gradient experiment.ixture was ignited from lean side.An experimental study was conducted in a combustion chamber.The combustion chamber has glass windows for optical measurements at any side.For the measurement of distribution of fuel concentration,infraed absorption method using 3.39μm He-Ne laser was used,and for the observation of proagating flams,Schlieren method was employed.As a measurment result of flame propagation velocity and flammable limit,for a mixture of an identical local equivalence ratio.flame propagation velocity in concentration gradient is faster than that in homogeneous mixture,and rich flammable limit in concentration gradient shows a tendency to be higher than that in homogeneous mixture.

  13. Numerical investigations of gaseous spherical diffusion flames

    Lecoustre, Vivien R.

    Spherical diffusion flames have several unique characteristics that make them attractive from experimental and theoretical perspectives. They can be modeled with one spatial dimension, which frees computational resources for detailed chemistry, transport, and radiative loss models. This dissertation is a numerical study of two classes of spherical diffusion flames: hydrogen micro-diffusion flames, emphasizing kinetic extinction, and ethylene diffusion flames, emphasizing sooting limits. The flames were modeled using a one-dimensional, time-accurate diffusion flame code with detailed chemistry and transport. Radiative losses from products were modeled using a detailed absorption/emission statistical narrow band model and the discrete ordinates method. During this work the code has been enhanced by the implementation of a soot formation/oxidation model using the method of moments. Hydrogen micro-diffusion flames were studied experimentally and numerically. The experiments involved gas jets of hydrogen. At their quenching limits, these flames had heat release rates of 0.46 and 0.25 W in air and in oxygen, respectively. These are the weakest flames ever observed. The modeling results confirmed the quenching limits and revealed high rates of reactant leakage near the limits. The effects of the burner size and mass flow rate were predicted to have a significant impact on the flame chemistry and species distribution profiles, favoring kinetic extinction. Spherical ethylene diffusion flames at their sooting limits were also examined. Seventeen normal and inverse spherical flames were considered. Initially sooty, these flames were experimentally observed to reach their sooting limits 2 s after ignition. Structure of the flames at 2 s was considered, with an emphasis on the relationships among local temperature, carbon to oxygen atom ratio (C/O), and scalar dissipation rate. A critical C/O ratio was identified, along with two different sooting limit regimes. Diffusion flames

  14. Transportation of nanoscale cargoes by myosin propelled actin filaments.

    Malin Persson

    Full Text Available Myosin II propelled actin filaments move ten times faster than kinesin driven microtubules and are thus attractive candidates as cargo-transporting shuttles in motor driven lab-on-a-chip devices. In addition, actomyosin-based transportation of nanoparticles is useful in various fundamental studies. However, it is poorly understood how actomyosin function is affected by different number of nanoscale cargoes, by cargo size, and by the mode of cargo-attachment to the actin filament. This is studied here using biotin/fluorophores, streptavidin, streptavidin-coated quantum dots, and liposomes as model cargoes attached to monomers along the actin filaments ("side-attached" or to the trailing filament end via the plus end capping protein CapZ. Long-distance transportation (>100 µm could be seen for all cargoes independently of attachment mode but the fraction of motile filaments decreased with increasing number of side-attached cargoes, a reduction that occurred within a range of 10-50 streptavidin molecules, 1-10 quantum dots or with just 1 liposome. However, as observed by monitoring these motile filaments with the attached cargo, the velocity was little affected. This also applied for end-attached cargoes where the attachment was mediated by CapZ. The results with side-attached cargoes argue against certain models for chemomechanical energy transduction in actomyosin and give important insights of relevance for effective exploitation of actomyosin-based cargo-transportation in molecular diagnostics and other nanotechnological applications. The attachment of quantum dots via CapZ, without appreciable modulation of actomyosin function, is useful in fundamental studies as exemplified here by tracking with nanometer accuracy.

  15. Heat and mass transfer in flames

    Faeth, G. M.


    Heat- and mass-transfer processes in turbulent diffusion flames are discussed, considering turbulent mixing and the structure of single-phase flames, drop processes in spray flames, and nonluminous and luminous flame radiation. Interactions between turbulence and other phenomena are emphasized, concentrating on past work of the author and his associates. The conserved-scalar formalism, along with the laminar-flamelet approximation, is shown to provide reasonable estimates of the structure of gas flames, with modest levels of empiricism. Extending this approach to spray flames has highlighted the importance of drop/turbulence interactions; e.g., turbulent dispersion of drops, modification of turbulence by drops, etc. Stochastic methods being developed to treat these phenomena are yielding encouraging results.

  16. Extinction of corrugated hydrogen/air flames

    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




    Full Text Available The aim of this investigation is to comprehensively understand the polymeric composite behavior under direct fire sources. The synergistic effects of hybrid flame retardant material on inhabiting the pyrolysis of hybrid reinforced fibers, woven roving (0°- 45° carbon and kevlar (50/50 wt/wt, and an araldite resin composites were studied. The composites were synthesised and coated primarily by zinc borate (2ZnO.3B2O3.3.5H2O and modified by antimony trioxide (Sb2O3 with different amounts (10-30 wt% of flame retardant materials. In the experiments, the composite samples were exposed to a direct flame source generated by oxyacetylene flame (~3000ºC at variable exposure distances of 10-20 mm. The synergic flame retardants role of antimony trioxide and zinc borate on the composite surface noticeably improves the flame resistance of the composite which is attributed to forming a protective mass and heat barrier on the composite surface and increasing the melt viscosity.

  18. Microgravity Turbulent Gas-Jet Diffusion Flames


    A gas-jet diffusion flame is similar to the flame on a Bunsen burner, where a gaseous fuel (e.g., propane) flows from a nozzle into an oxygen-containing atmosphere (e.g., air). The difference is that a Bunsen burner allows for (partial) premixing of the fuel and the air, whereas a diffusion flame is not premixed and gets its oxygen (principally) by diffusion from the atmosphere around the flame. Simple gas-jet diffusion flames are often used for combustion studies because they embody the mechanisms operating in accidental fires and in practical combustion systems. However, most practical combustion is turbulent (i.e., with random flow vortices), which enhances the fuel/air mixing. These turbulent flames are not well understood because their random and transient nature complicates analysis. Normal gravity studies of turbulence in gas-jet diffusion flames can be impeded by buoyancy-induced instabilities. These gravitycaused instabilities, which are evident in the flickering of a candle flame in normal gravity, interfere with the study of turbulent gas-jet diffusion flames. By conducting experiments in microgravity, where buoyant instabilities are avoided, we at the NASA Lewis Research Center hope to improve our understanding of turbulent combustion. Ultimately, this could lead to improvements in combustor design, yielding higher efficiency and lower pollutant emissions. Gas-jet diffusion flames are often researched as model flames, because they embody mechanisms operating in both accidental fires and practical combustion systems (see the first figure). In normal gravity laboratory research, buoyant air flows, which are often negligible in practical situations, dominate the heat and mass transfer processes. Microgravity research studies, however, are not constrained by buoyant air flows, and new, unique information on the behavior of gas-jet diffusion flames has been obtained.

  19. 33 CFR 154.822 - Detonation arresters, flame arresters, and flame screens.


    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Detonation arresters, flame... BULK Vapor Control Systems § 154.822 Detonation arresters, flame arresters, and flame screens. (a) Each detonation arrester required by this part must: (1) Be capable of arresting a detonation from either side...

  20. Information tecnology and its impact on port cargo distribution businness

    Trampus, Francesca


    The IT revolution has dynamised the port cargo business: up-to-date software is needed to optimize operations such as vessel loading, yard planning, equipment flow, gate handling, administration and invoicing and it is also essential for vessel tracking, electronic declaration of cargo and passengers and as a communication platform to all port users.

  1. 29 CFR 1917.14 - Stacking of cargo and pallets.


    ... 29 Labor 7 2010-07-01 2010-07-01 false Stacking of cargo and pallets. 1917.14 Section 1917.14 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... pallets. Cargo, pallets and other material stored in tiers shall be stacked in such a manner as to...

  2. 33 CFR 155.775 - Maximum cargo level of oil.


    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Maximum cargo level of oil. 155.775 Section 155.775 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... Personnel, Procedures, Equipment, and Records § 155.775 Maximum cargo level of oil. (a) For the purposes...

  3. Visible structure of buoyant diffusion flames

    Zukoski, E. E.; Cetegen, B. M.; Kubota, T.


    Natural gas diffusion flames stabilized on 0.10, 0.19 and 0.50 m. diameter porous bed burners have been studied for heat release rates ranging from 10 to 200 kW. Flame heights were measured from video tape recordings and by eye averaged techniques. The dependence of flame height on a dimensionless heat addition parameter shows a transition for values of the parameter around unity. For flames taller than three burner diameters, the initial diameter of the fire does not affect the length of the...

  4. Laser Ionization Studies of Hydrocarbon Flames.

    Bernstein, Jeffrey Scott

    Resonance-enhanced multiphoton ionization (REMPI) and laser induced fluorescence (LIF) are applied as laser based flame diagnostics for studies of hydrocarbon combustion chemistry. rm CH_4/O_2, C _2H_4/O_2, and rm C_2H_6/O_2 low pressure ( ~20 Torr), stoichiometric burner stabilized flat flames are studied. Density profiles of intermediate flame species, existing at ppm concentrations, are mapped out as a function of distance from the burner head. Profiles resulting from REMPI and LIF detection are obtained for HCO, CH_3, H, O, OH, CH, and CO flame radicals. The above flame systems are computer modeled against currently accepted combustion mechanisms using the Chemkin and Premix flame codes developed at Sandia National Laboratories. The modeled profile densities show good agreement with the experimental results of the CH_4/O_2 flame system, thus confirming the current C1 kinetic flame mechanism. Discrepancies between experimental and modeled results are found with the C2 flames. These discrepancies are partially amended by modifying the rate constant of the rm C_2H_3+rm O_2 to H_2CO + HCO reaction. The modeled results computed with the modified rate constant strongly suggest that the kinetics of several or possibly many reactions in the C2 mechanism need refinement.

  5. Atomic absorption spectroscopy with high temperature flames.

    Willis, J B


    An account is given of the history of the development of high temperature flames for the atomic absorption measurement of metals forming refractory oxides. The principles governing the design of premix burners for such flames, and the relative merits of different types of nebulizer burner systems are described. After a brief account of the structure and emission characteristics of the premixed oxygen-acetylene and nitrous oxide-acetylene flames, the scope and limitations of the latter flame in chemical analysis are discussed. PMID:20068790

  6. Imaging of premixed flames in microgravity

    Kostiuk, L. W.; Cheng, R. K.


    A laser schlieren system which uses video recording and digital images analysis has been developed and applied successfully to microgravity combustion experiments performed in a drop-tower. The optical system and the experiment are installed within a small package which is subjected to free-fall. The images are recorded on video tape and are digitized and analyzed by a computer-controlled image processor. The experimental results include laminar and turbulent premixed conical flames in microgravity, normal positive gravity (upward), and reverse gravity (downward). The procedures to extract frequency information from the digitized images are described. Many gross features of the effects of gravity on premixed conical flames are found. Flames that ignite easily in normal gravity fail to ignite in microgravity. Buoyancy driven instabilities associated with an interface formed between the hot products and the cold surrounding air is the mechanism through which gravity influences premixed laminar and turbulent flames. In normal gravity, this causes the flame to flicker. In reverse gravity, - g, and microgravity, μg, the interface is stable and flame flickering ceases. The flickering frequencies of + g flames vary with changing upstream boundary conditions. The absence of flame flickering in μg suggest that μg flames would be less sensitive to these changes.

  7. Pole solutions for flame front propagation

    Kupervasser, Oleg


    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.

  8. Environmental control of microtubule-based bidirectional cargo-transport

    Klein, Sarah; Santen, Ludger


    Inside cells, various cargos are transported by teams of molecular motors. Intriguingly, the motors involved generally have opposite pulling directions, and the resulting cargo dynamics is a biased stochastic motion. It is an open question how the cell can control this bias. Here we develop a model which takes explicitly into account the elastic coupling of the cargo with each motor. We show that bias can be simply controlled or even reversed in a counterintuitive manner via a change in the external force exerted on the cargo or a variation of the ATP binding rate to motors. Furthermore, the superdiffusive behavior found at short time scales indicates the emergence of motor cooperation induced by cargo-mediated coupling.

  9. Experimental studies of flame stability limits of biogas flame

    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 CO2 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 CO2 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 CO2 concentration. The yellow tipping limits are extended with an increase of CO2 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 CO2 concentration in biogas and with an increase of port diameter or gas temperature.

  10. Fatalities to occupants of cargo areas of pickup trucks.

    Anderson, C L; Agran, P F; Winn, D G; Greenland, S


    We sought to describe the fatalities to occupants of pickup truck cargo areas and to compare the mortality of cargo area occupants to passengers in the cab. From the Fatality Analysis Reporting System (FARS) files for 1987-1996, we identified occupants of pickup trucks with at least one fatality and at least one passenger in the cargo area. Outcomes of cargo area occupants and passengers in the cab were compared using estimating equations conditional on the crash and vehicle. Thirty-four percent of deaths to cargo occupants were in noncrash events without vehicle deformation. Fifty-five percent of those who died were age 15-29 years and 79% were male. The fatality risk ratio (FRR) comparing cargo area occupants to front seat occupants was 3.0 (95% Confidence Interval [CI] = 2.7-3.4). The risk was 7.9 (95% CI = 6.2-10.1) times that of restrained front seat occupants. The FRR ranged from 92 (95% CI = 47-179) in noncrash events to 1.7 (95% CI = 1.5-1.9) in crashes with severe vehicle deformation. The FRR was 1.8 (95% CI = 1.4-2.3) for occupants of enclosed cargo areas and 3.5 (95% CI = 3.1-4.0) for occupants of open cargo areas. We conclude that passengers in cargo areas of pickup trucks have a higher risk of death than front seat occupants, especially in noncrash events, and that camper shells offer only limited protection for cargo area occupants. PMID:10868756

  11. Dose to drivers during drive-through cargo scanning using GEANT4 Monte Carlo simulation

    Gomes, Rogerio S.; Gomes, Joana D' Arc R.L.; Costa, Mara Lucia L., E-mail:, E-mail:, E-mail: [Comissao Nacional de Energia Nuclear (CNEN-RJ), Rio de Janeiro, RJ (Brazil). Diretoria de Radioprotecao e Seguranca muclear; Miranda, Valeria F.E.S., E-mail: [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)


    The use of radiation technologies to perform screening for cargo containers has been increased due to security issues, mainly, as a consequence of the United States (US) legislation which requires, from 2013, the scanning of all intermodal cargo containers which arrive at US ports. Currently, systems to cargo inspections, using accelerator-driven high energy X-rays, between 4 and 9 MeV, are available for scanning operations. It is expected that, in the future, the use of these systems will be widely spread on roads, ports and airports in Brazil. However, in order to improve the productivity and reduce the costs of acquisition, operation and maintenance these systems require that the driver drives its vehicle through irradiation area, in a situation where members of the public (the truck drivers) enter in controlled area and are deliberately exposed to high-energy beam. Some manufacturers justifies this procedure arguing that the drivers are exposed briefly, and only to the scattered beam, since there are safety systems in order to avoid that the drivers are exposed to direct beam. In this work, it is presented the preliminary results of Monte Carlo simulations concerning the dose of drivers during scanning operations, including the dose due to a failure of safety system, producing an exposure of drivers to the direct beam, as well as, an analysis of the justification of practice, mainly related to the drive-through operational procedure. (author)

  12. Interaction of Two Micro-slot Flames: Heat Release Rate and Flame Shape

    This paper studies the interaction between two identical micro-slot diffusion flames. Here, we define a micro-slot flame as a slot flame of which the slot width is less than about 1 mm. Because of its smallness, a micro-slot flame has a high heating density and can be used as a small heat source. However, the heat release rate of a single micro-slot flame is limited, and therefore, multiple micro-slot flames may be used to increase total heat release rate. As a first step, this paper considers a situation in which two micro-slot flames are used with certain burner spacing. When two diffusion flames are placed closely, flame shape changes from that of an isolated flame. Studying such flame shape change and resultant change in total heat release rate is the topic of this paper. Experiment is conducted and total heat release rate is measured by integrating CH* chemiluminescence recorded using a CCD camera and an optical filter of the wavelength of 430 nm. Two different burner materials, copper and glass, are tested to study the effect of heat loss to burners. An analytical model is applied to predict flame shape. In addition to the classical Burke-Schumann assumptions, two slot flames are modeled as line sources with zero width, enabling a simple analytical solution for the critical burner spacing at which two flames touch each other. The critical burner spacing is a key parameter that characterizes the interaction between two micro-slot flames. Computational fluid dynamics (CFD) simulations are then conducted to test the validity of the present theory. CFD results are favorably compared with the theoretical prediction

  13. 49 CFR 1546.213 - Access to cargo: Security threat assessments for cargo personnel in the United States.


    ... 49 Transportation 9 2010-10-01 2010-10-01 false Access to cargo: Security threat assessments for...: Security threat assessments for cargo personnel in the United States. This section applies in the United...— (1) Each individual must successfully complete a security threat assessment or comparable...

  14. 49 CFR 1548.15 - Access to cargo: Security threat assessments for individuals having unescorted access to cargo.


    ... 49 Transportation 9 2010-10-01 2010-10-01 false Access to cargo: Security threat assessments for... SECURITY CIVIL AVIATION SECURITY INDIRECT AIR CARRIER SECURITY § 1548.15 Access to cargo: Security threat... must successfully complete a security threat assessment or comparable security threat...

  15. Magnetically triggered release of molecular cargo from iron oxide nanoparticle loaded microcapsules

    Carregal-Romero, Susana; Guardia, Pablo; Yu, Xiang; Hartmann, Raimo; Pellegrino, Teresa; Parak, Wolfgang J.


    Photothermal release of cargo molecules has been extensively studied for bioapplications. For instance, microcapsules decorated with plasmonic nanoparticles have been widely used in in vitro assays. However, some concerns about their suitability for some in vivo applications cannot be easily overcome, in particular the limited penetration depth of light (even infrared). Magnetic nanoparticles are alternative heat-mediators for local heating, which can be triggered by applying an alternating magnetic field (AMF). AMFs are much less absorbed by tissue than light and thus can penetrate deeper overcoming the above mentioned limitations. Here we present iron oxide nanocube-modified microcapsules as a platform for magnetically triggered molecular release. Layer-by-layer assembled polyelectrolyte microcapsules with 4.6 μm diameter, which had 18 nm diameter iron oxide nanocubes integrated in their walls, were synthesized. The microcapsules were further loaded with an organic fluorescent polymer (Cascade Blue-labelled dextran), which was used as a model of molecular cargo. Through an AMF the magnetic nanoparticles were able to heat their surroundings and destroy the microcapsule walls, leading to a final release of the embedded cargo to the surrounding solution. The cargo release was monitored in solution by measuring the increase in both absorbance and fluorescence signal after the exposure to an AMF. Our results demonstrate that magnetothermal release of the encapsulated material is possible using magnetic nanoparticles with a high heating performance.Photothermal release of cargo molecules has been extensively studied for bioapplications. For instance, microcapsules decorated with plasmonic nanoparticles have been widely used in in vitro assays. However, some concerns about their suitability for some in vivo applications cannot be easily overcome, in particular the limited penetration depth of light (even infrared). Magnetic nanoparticles are alternative heat

  16. 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

    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:; 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)


    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.

  17. Flame dynamics of a meso-scale heat recirculating combustor

    Vijayan, V.; Gupta, A.K. [Department of Mechanical Engineering, University of Maryland, College Park, MD 20742 (United States)


    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. Toxicity of brominated flame retardants with focus on retinoid system disturbances

    Litens Karlsson, Sabina


    Background: Brominated flame retardants (BFR) are detected in the environment and biota all over the world. They contribute to the human body burden of industrial chemicals and exposure is mainly via food. Indoor dust contributes substantially in some exposure situations, which involve small children. Regulatory restrictions and bans have been introduced as some BFRs can impact proper development, potentially via the endocrine system. Objectives: The study aim was to clarify the role of...

  19. Transporting "exceptional cargo" on the CERN sites

    EN Department


    When the Transport Service is managing "exceptional cargo", the driver and the escort are often in charge of an operation involving equipment worth many hundred thousand francs. Equipment that may well be irreplaceable for a facility or an experiment.   The members of the Transport Service who carry out these tasks are very professional and are – needless to say – highly concentrated on the job. They count on your understanding and support in the traffic on site. Their convoys are – for good reasons – moving slowly. Kindly do not overtake, do not cut in in front of them and do not drive too closely. Respect the escort and do not position yourself between the truck and the escort vehicles. The EN department counts on your courtesy on the road.  

  20. A Liquid Cargo Handling Training Simulator

    Malvin Villabø


    Full Text Available This paper describes a computer-based, real-time training simulator for liquid cargo handling. The mathematical model description is modular and emphasizes the flow generating part. The flow model applies network theory to describe the logical piping connections and the overall flow system performance, while Bernoulli's equation is used for the description of the piping elements. Numerically the Newton-Raphson method is applied for computation of the non-linear flow model. The programming language is HP-FORTRAN IV and the simulator is implemented on an HP minicomputer system. The instructor part of the system is interactive and controlled by the use of a standard ASCII terminal. The simulation part of the system is running in real-time or scaled real-time, and is controlled from the trainee's panel.

  1. Impact of flame-wall interaction on premixed flame dynamics and transfer function characteristics

    Kedia, K.S.


    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.

  2. Analysis of Premixed Flame Response and Rayleigh Criterion through a Novel Flame Transfer Function

    Rani, Vijaya Krishna; Rani, Sarma


    Linear modal analysis of combustion instabilities requires a flame transfer function which describes the flame heat-release response to acoustic perturbations. In this study, a novel flame transfer function (FTF) is developed that provides an explicit relationship between heat-release and pressure fluctuations for laminar premixed flames. While the FTF is generalized for any mean flame shape, a triangular mean flame stabilized at the cross-sectional interface of a dump combustor is analyzed. For this flame, the effects on the FTF magnitude and phase of the acoustic frequency, location (on the mean flame), modal index, and the mean Mach number are investigated. To illustrate and analyze the Rayleigh's criterion, the spatio-temporal integral of the correlation of pressure and heat-release fluctuations is calculated. It is found that the magnitude of the FTF shows harmonic-like oscillations whose amplitude decreases with frequency, suggesting that the flame shows preferential response to certain frequencies than others. The oscillatory behavior becomes increasingly prominent as one moves away from the flame anchoring point(s). Finally, evaluation of the Rayleigh integral clearly demonstrates the flame-acoustic phase shifts at which combustion instability may arise.

  3. Nonequilibrium theory of flame propagation

    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

  4. Flame Imaging of Gas-Turbine Relight

    Read, Robert; Rogerson, J.W.; Hochgreb, S.


    . The motion of hot gases during the early stages of relight is recorded using a high-speed camera. An algorithm is developed to track the flame movement and breakup, revealing important characteristics of the flame development process, including stabilization timescales, spatial trajectories, and typical...

  5. Flaming in CMC: Prometheus' Fire or Inferno's?

    Abrams, Zsuzsanna Ittzes


    Reports on a descriptive study with 75 intermediate college learners of German participating in two sessions of synchronous computer mediated communication during the course of a semester that investigated students' flaming behavior--aggressive interpersonal language and rude behavior. Shows that not only is flaming a very infrequent occurrence,…

  6. Active control for turbulent premixed flame simulations

    Bell, John B.; Day, Marcus S.; Grcar, Joseph F.; Lijewski, Michael J.


    Many turbulent premixed flames of practical interest are statistically stationary. They occur in combustors that have anchoring mechanisms to prevent blow-off and flashback. The stabilization devices often introduce a level of geometric complexity that is prohibitive for detailed computational studies of turbulent flame dynamics. As a result, typical detailed simulations are performed in simplified model configurations such as decaying isotropic turbulence or inflowing turbulence. In these configurations, the turbulence seen by the flame either decays or, in the latter case, increases as the flame accelerates toward the turbulent inflow. This limits the duration of the eddy evolutions experienced by the flame at a given level of turbulent intensity, so that statistically valid observations cannot be made. In this paper, we apply a feedback control to computationally stabilize an otherwise unstable turbulent premixed flame in two dimensions. For the simulations, we specify turbulent in flow conditions and dynamically adjust the integrated fueling rate to control the mean location of the flame in the domain. We outline the numerical procedure, and illustrate the behavior of the control algorithm. We use the simulations to study the propagation and the local chemical variability of turbulent flame chemistry.

  7. Chemical processes in the HNF flame

    Ermolin, N.E.; Zarko, V.E.; Keizers, H.L.J.


    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

  8. Injuries to occupants in cargo areas of pickup trucks.

    Agran, P; Winn, D; Anderson, C


    Transporting passengers in the cargo area of pickup trucks is a public health safety issue in the United States. Our study compared crashes involving passengers in the cargo area with those involving passengers in the cab. We obtained data for all injury events of pickup occupants for 1990 from the California Highway Patrol. A total of 702 traffic reports coded as having passengers riding in pickup truck beds involved 1,685 passengers in the cargo area and 865 in the cab. Significantly more events involving passengers in the cargo area occurred in summer in rural areas and were noncollisions than did events with only cab passengers. Crashes with passengers in the cargo area resulted in death in 5% of passengers. Of the drivers, 81% were male and 22% were younger than 20 years. Among the 1,685 passengers in the cargo area, 65% were male, 36% were younger than 15 years, and 30% were ages 15 to 19 years. Passengers in the cargo area were more frequently ejected and more seriously injured than their counterparts in the cab. Legislation to restrict travel in truck beds and the design of restraints for this area are some measures that may reduce the risk of injury. PMID:7810125

  9. Effects of gravity on turbulent nonpremixed flames

    Elghobashi, S.; Zhong, R.; Boratav, O.


    The paper examines the effects of buoyancy on the behavior of turbulent nonpremixed flames using the method of direct numerical simulation. We examine the effects of the interactions between turbulence, chemical reaction, and buoyancy on the fields of vorticity, turbulence kinetic energy, scalar dissipation, and reaction rate. In the buoyant flame, the baroclinic torque creates strong counter-rotating vortices saddling the flame surface. These vortices result in a significantly more wrinkled flame surface than in the nonbuoyant case. One of the effects of wrinkling is that it reduces the distances between the isosurfaces of the mixture fraction F, thus augmenting the local ∇F and the scalar dissipation ɛF, and consequently the reaction rate ṙT. The zones of maximum ṙT coincide with those of maximum tangential extensional strain. Our results show a direct correlation between ɛF and ṙT for both the buoyant and nonbuoyant flames.

  10. Propagation Regime of Iron Dust Flames

    Tang, Francois-David; Goroshin, Samuel; Higgins, Andrew J.


    A flame propagating through an iron-dust mixture can propagate in two asymptotic regimes. When the characteristic time of heat transfer between particles is much smaller than the characteristic time of particle combustion, the flame propagates in the continuum regime where the heat released by reacting particles can be modelled as a space-averaged function. In contrast, when the characteristic time of heat transfer is much larger than the particle reaction time, the flame can no longer be treated as a continuum due to dominating effects associated with the discrete nature of the particle reaction. The discrete regime is characterized by weak dependence of the flame speed on the oxygen concentration compared to the continuum regime. The discrete regime is observed in flames propagating through an iron dust cloud within a gas mixture containing xenon, while the continuum regime is obtained when xenon is substituted with helium.

  11. Rayleigh-Taylor Unstable Flames -- Fast or Faster?

    Hicks, E. P.


    Rayleigh-Taylor (RT) unstable flames play a key role in the explosions of supernovae Ia. However, the dynamics of these flames are still not well understood. RT unstable flames are affected by both the RT instability of the flame front and by RT-generated turbulence. The coexistence of these factors complicates the choice of flame speed subgrid models for full-star Type Ia simulations. Both processes can stretch and wrinkle the flame surface, increasing its area and, therefore, the burning rate. In past research, subgrid models have been based on either the RT instability or turbulence setting the flame speed. We evaluate both models, checking their assumptions and their ability to correctly predict the turbulent flame speed. Specifically, we analyze a large parameter study of 3D direct numerical simulations of RT unstable model flames. This study varies both the simulation domain width and the gravity in order to probe a wide range of flame behaviors. We show that RT unstable flames are different from traditional turbulent flames: they are thinner rather than thicker when turbulence is stronger. We also show that none of the several different types of turbulent flame speed models accurately predicts measured flame speeds. In addition, we find that the RT flame speed model only correctly predicts the measured flame speed in a certain parameter regime. Finally, we propose that the formation of cusps may be the factor causing the flame to propagate more quickly than predicted by the RT model.

  12. Technical and economic evaluation of advanced air cargo system concepts

    Whitehead, A. H., Jr.


    The paper reviews NASA air cargo market studies, reports on NASA and NASA-sponsored studies of advanced freighter concepts, and identifies the opportunities for the application of advanced technology. The air cargo market is studied to evaluate the timing for, and the potential market response to, advanced technology aircraft. The degree of elasticity in future air freight markets is also being investigated, since the demand for a new aircraft is most favorable in a price-sensitive environment. Aircraft design studies are considered with attention to mission and design requirements, incorporation of advanced technologies in transport aircraft, new cargo aircraft concepts, advanced freighter evaluation, and civil-military design commonality.

  13. The flaming gypsy skirt injury.

    Leong, S C L; Emecheta, I E; James, M I


    On review of admissions over a 12-month period, we noted a significant number of women presenting with gypsy skirt burns. We describe all six cases to highlight the unique distribution of the wounds and the circumstances in which the accidents occurred. Four skirts were ignited by open fire heaters: two skirts ignited whilst the women were standing nearby, distracted with a telephone conversation; one brushed over the flame as she was walking past the heater; other whilst dancing in the lounge. One skirt was ignited by decorative candles placed on the floor during a social gathering. Another skirt was set alight by cigarette ember, whilst smoking in the toilet. Percentage surface area burned, estimated according to the rule of nines, showed that gypsy skirt burns were significant ranging from 7 to 14% total body surface area (TBSA) and averaging 9% TBSA. Two patients required allogenic split-skin grafts. Common sense care with proximity to naked flame is all that is needed to prevent this injury. PMID:17081546

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

    Al-Noman, Saeed M.


    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

  15. Flame Structure and Emissions of Strongly-Pulsed Turbulent Diffusion Flames with Swirl

    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

  16. 19 CFR 122.117 - Requirements for transit air cargo transport.


    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Requirements for transit air cargo transport. 122... Requirements for transit air cargo transport. (a) Transportation—(1) Port to port. Transit air cargo may be... cargo, a receipt shall be given. The receipt shall be made by the airline responsible for transport...

  17. 46 CFR 153.436 - Heat transfer fluids: compatibility with cargo.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Heat transfer fluids: compatibility with cargo. 153.436... Equipment Cargo Temperature Control Systems § 153.436 Heat transfer fluids: compatibility with cargo. A heat transfer fluid separated from the cargo by only one wall (for example, the heat transfer fluid in a...

  18. 46 CFR 153.371 - Minimum relief valve setting for refrigerated cargo tanks.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Minimum relief valve setting for refrigerated cargo... Design and Equipment Cargo Venting Systems § 153.371 Minimum relief valve setting for refrigerated cargo tanks. The relief valve setting for a containment system that carries a refrigerated cargo must at...

  19. 46 CFR 153.438 - Cargo pressure or temperature alarms required.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo pressure or temperature alarms required. 153.438... Equipment Cargo Temperature Control Systems § 153.438 Cargo pressure or temperature alarms required. (a... vapor pressure described in § 153.371(b); or (2) An alarm that operates when the cargo's...

  20. 46 CFR 154.707 - Cargo boil-off as fuel: Ventilation.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo boil-off as fuel: Ventilation. 154.707 Section 154.707 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES... Equipment Cargo Pressure and Temperature Control § 154.707 Cargo boil-off as fuel: Ventilation. (a)...

  1. 46 CFR 98.25-55 - Cargo piping.


    ... piping by means of seamless steel pipe expansion bends. Special consideration will be given for packless... Cargo piping. (a) Piping shall be of seamless steel meeting the requirements of § 56.60-1 of...

  2. Bidirectionality From Cargo Thermal Fluctuations in Motor-Mediated Transport

    Miles, Christopher E


    Molecular motor proteins serve as an essential component of intracellular transport by generating forces to haul cargoes along cytoskeletal filaments. In some circumstances, two species of motors that are directed oppositely (e.g. kinesin, dynein) can be attached to the same cargo. The resulting net motion is known to be bidirectional, but the mechanism of switching remains unclear. In this work, we propose a mean-field mathematical model of the mechanical interactions of two populations of molecular motors with diffusion of the cargo (thermal fluctuations) as the fundamental noise source. By studying a simplified model, the delayed response of motors to rapid fluctuations in the cargo is quantified, allowing for the reduction of the full model to two "characteristic positions" of each of the motor populations. The system is then found to be "metastable", switching between two distinct directional transport states, or bidirectional motion. The time to switch between these states is then investigated using WKB...

  3. 46 CFR 98.25-80 - Cargo hose.


    ... rubber or other hose material acceptable to the Commandant, shall be fitted to the liquid or vapor lines... valve. (d) Before being placed in service, each new cargo hose, with all necessary fittings...

  4. Stochastic modeling of cargo transport by teams of molecular motors

    Klein, Sarah; Santen, Ludger


    Many different types of cellular cargos are transported bidirectionally along microtubules by teams of molecular motors. The motion of this cargo-motors system has been experimentally characterized in vivo as processive with rather persistent directionality. Different theoretical approaches have been suggested in order to explore the origin of this kind of motion. An effective theoretical approach, introduced by M\\"uller et al., describes the cargo dynamics as a tug-of-war between different kinds of motors. An alternative approach has been suggested recently by Kunwar et al., who considered the coupling between motor and cargo in more detail. Based on this framework we introduce a model considering single motor positions which we propagate in continuous time. Furthermore, we analyze the possible influence of the discrete time update schemes used in previous publications on the system's dynamic.

  5. Multi-Purpose Logistics Module (MPLM) Cargo Heat Exchanger

    Zampiceni, John J.; Harper, Lon T.


    This paper describes the New Shuttle Orbiter's Multi- Purpose Logistics Modulo (MPLM) Cargo Heat Exchanger (HX) and associated MPLM cooling system. This paper presents Heat Exchanger (HX) design and performance characteristics of the system.

  6. Bidirectional cargo transport: Moving beyond tug-of-war

    Hancock, William O.


    Preface Vesicles, organelles and other intracellular cargo are transported by kinesin and dynein motors, which move in opposite directions along microtubules. This bidirectional cargo movement is frequently described as a “tug-of-war” between oppositely-directed motors attached to the same cargo. However, although many experimental and modeling studies support the tug-of-war paradigm, numerous knockout and inhibition studies in a variety of systems have found that inhibiting one motor leads to diminished motility in both directions, which is a “paradox of codependence” that challenges it. In an effort to resolve this paradox, three classes of bidirectional transport models, termed microtubule tethering, mechanical activation, and steric disinhibition, are proposed and a general mathematical modeling framework for bidirectional cargo transport is put forward to guide future experiments. PMID:25118718

  7. 33 CFR 157.134 - Cargo tank drainage.


    ...) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK Crude Oil Washing (COW) System on Tank Vessels Design, Equipment, and Installation § 157.134 Cargo...

  8. Aggregating Secondary Source Data for Air Cargo Prescreening Project

    National Aeronautics and Space Administration — We propose to improve the effectiveness of air cargo prescreening by enabling background knowledge about companies and products to be used for threat assessment....

  9. Progress and challenges in swirling flame dynamics

    Candel, Sébastien; Durox, Daniel; Schuller, Thierry; Palies, Paul; Bourgouin, Jean-François; Moeck, Jonas P.


    In many continuous combustion processes the flame is stabilized by swirling the injected flow. This is the case for example in aeroengine combustors or in gas turbines where aerodynamic injectors impart a rotating component to the flow to create a central recirculation zone which anchors the flame. Swirling flame dynamics is of technical interest and also gives rise to interesting scientific issues. Some of the recent progress in this field will be reviewed. It is first shown that the swirler response to incident acoustic perturbations generates a vorticity wave which is convected by the flow. A result of this process is that the swirl number fluctuates. It is then shown that the flame response is defined by a combination of heat release rate fluctuations induced by the incoming acoustic and convective perturbations. This is confirmed by experimental measurements and by large eddy simulations of the reactive flow. Measured flame describing functions (FDFs) are then used to characterize the nonlinear response of swirling flames to incident perturbations and determine the regimes of instability of a generic system comprising an upstream manifold, an injector equipped with a swirler and a combustion chamber confining the flame. The last part of this article is concerned with interactions of the precessing vortex core (PVC) with incoming acoustic perturbations. The PVC is formed at high swirl number and this hydrodynamic helical instability gives rise to some interesting nonlinear interactions between the acoustic frequency, the PVC frequency and their difference frequency.

  10. Fluid-Plasma Coupling in Hydrogen Flames

    Massa, Luca; Retter, Jonathan; Glumac, Nick; Elliot, Gregg; Freund, Jonathan


    Recent experiments show that hydrogen diffusion flames at low Reynolds number can be markedly affected by a dielectric barrier discharge (DBD) plasma. The flame surface deforms and flattens, and light emissions increase. We develop a simulation model to analyze the mechanisms that causes these changes, and apply it to numerical calculations of axisymmetric flames with co-annular DBD, matching the corresponding experiments. Body forces due to charge sheaths are found to be the main mechanism, with radicals produced by plasma excitation playing a secondary role for the present conditions. The non-actuated flame flickers at approximately 10 Hz, in good agreement with the experiments. As the DBD voltage is increased, the flame flattens and oscillations decrease, eventually ceasing above a threshold value. The fully flattened case has a stoichiometric surface lying flat across the fuel orifice, with flame temperature exceeding significantly the adiabatic flame value. A force based on a linearized plasma sheath model, calibrated against air experiments, reproduces the main features of the experiments and provides a good estimate for the threshold flattening potential. In faster flowing regimes, radical production by the plasma becomes more important.

  11. Particle clustering in turbulent premixed flames

    F, Battista; F, Picano; G, Troiani; M, Casciola C.


    Transport of inertial particles in turbulent reacting flows is frequent in a number of engineering and natural systems. Aim of this work is to illustrate the effect of the fluctuating instantaneous flame front on the particle spatial distribution. To this purpose a Direct Numerical Simulation of a Bunsen premixed flame seeded with small inertial particles is performed. The flamelet Stokes number Stfl, defined as the ratio between the particle relaxation time and the flame front time scale, is found to be the proper parameter to characterize the particle dynamics in a premixed flame. Clustering of inertial particles is apparent, especially beyond the flame front. The amount of particle segregation is here quantified by the clustering index and two distinct contributions are found to interplay. The first is independent of the particle inertia and affects also tracers. Actually it is associated to the abrupt variation of the particle concentration induced by the fluid expansion across the flame front. The second effect is mainly due to the time lag associated to the particle inertia that, in proximity of the front, affects both the mean and the fluctuation of the particle number in a fixed volume. The global effect results in an intense clustering of the inertial particles in the flame brush region with a maximum for particles with flamelet Stokes number: Stfl = Script O(1).

  12. Combustion characteristics of Mg−CO2 counterflow diffusion flames

    Fukuchi, Aporo; Kawashima, Masaru; Yuasa, Saburo


    To examine the details of the Mg−CO2 combustion consisting of the gas-phase reactions and the surface reactions, we tried to separate the Mg−CO2 flame from the surface reactions. For this purpose, we formed a stable Mg−CO2 counterflow diffusion flame between the Mg vapor and a CO2 stream by using a Mg vaporizer with many small ejection holes.The Mg−CO2 counterflow diffusion flames contained two types of flames: the luminous flame and the dark flame. In the luminous flame, the homogeneous reac...

  13. Role of compressibility in moderating flame acceleration in tubes.

    Bychkov, Vitaly; Akkerman, V'yacheslav; Valiev, Damir; Law, Chung K


    The effect of gas compression on spontaneous flame acceleration leading to deflagration-to-detonation transition is studied theoretically for small Reynolds number flame propagation from the closed end of a tube. The theory assumes weak compressibility through expansion in small Mach number. Results show that the flame front accelerates exponentially during the initial stage of propagation when the Mach number is negligible. With continuous increase in the flame velocity with respect to the tube wall, the flame-generated compression waves subsequently moderate the acceleration process by affecting the flame shape and velocity, as well as the flow driven by the flame. PMID:20365653

  14. The FLAME project in Atomki

    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: 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

  15. Flame Acceleration Tests with Hydrogen Combustions

    According to the domestic and foreign regulations, a detonation or DDT (deflagration to detonation transition) by a hydrogen combustion should be prohibited to occur in a containment of a nuclear power plant. A hydrogen control in the IRWST(Incontainment Refueling Water Storage Tank) under a severe accident still remains a debatable issue to be solved in APR1400. The characteristics of the hydrogen flame in the IRWST expected during the station black-out (SBO) and total loss of feed water (LOFW) accidents have been evaluated based on a sigma-lambda criteria from the simulation results by the numerical codes such as GASFLOW. And it was found that hydrogen mixture was non-flammable most of the accident time when the non-condensed steam was released into the free volume of the IRWST, but there existed a small period of time with a high possibility of a flame acceleration during the SBO accident because most of the steam discharged from sparger was well condensed. Therefore, detail analysis and experiment of the hydrogen flame should be required to fix a DDT possibility by the hydrogen combustion in the IRWST of the APR1400. Most experiments on the hydrogen combustion have been limited only to straight pipes or channels. However, the hydrogen flame acceleration phenomena in the IRWST with a closed annular path may be different from those in the straight path in respect to a centrifugal force and degree of freedom in flame propagation etc. So, an experiment of hydrogen combustion in a closed annular chamber is needed to find out the geometrical effect on the flame propagation and to validate the numerical results. KAERI has been performing the experiments of the hydrogen combustion in the IRWST. As the fist stage, flame acceleration tests with the hydrogen combustions are studied preliminarily for a circular straight pipe to confirm the characteristics hydrogen flame propagation, and to evaluate flame detection systems

  16. The Cargo Tray Industry in India – A Market Research

    Eriksson, Martin; Ohlsson, Tobias


    Title: The Cargo Tray Industry in India – A Market Research Authors: Martin Eriksson and Tobias Ohlsson Supervisor: Cecilia Lindh University: University of MälardalenDepartment: School of Sustainable Development of Society and TechnologyCourse: Bachelor thesis in Business Administration, 15 credits Research question: Is the Indian cargo tray industry a promising place for Autoform to make futureinvestments? Target group: The primary target is Autoform. The secondary target group is other cara...


    Evstigneeva, Anastasia


    This Master Thesis was created because of great personal interest towards marine insurance as such ans cargo insurance in particular. The purpose of this work is to give a proper overview of three legal fields - Norwegian, English and Russian Law. Cargo insurance is of no doubts tremendously important nowadays. How often do people consider where the goods they use daily are coming from? Some tea from India, a new phone form Japan, household appliances from Germany. All these goods were made l...

  18. Prediction of flame formation in highly preheated air combustion

    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. Methane Formation by Flame-Generated Hydrogen Atoms in the Flame Ionization Detector

    Holm, Torkil; Madsen, Jørgen Øgaard


    The precombustion degradation of organic compounds in the flame ionization detector has been studied (1) by heating the additives in hydrogen in a quartz capillary and analyzing the reaction products by GC and (2) by following the degradation of the additives in a hydrogen flame, by means of a thin...... fused silica probe inserted from the bottom of the flame and connected to the ion source of a mass spectrometer. The results show that the thermic hydrogenolysis of hydrocarbons at flame temperatures produces mixtures of methane, ethene, and ethyne. In the flame, however, ethyne, benzene, isobutane...... atoms, which are formed in the burning hydrogen and which diffuse into the inner core of the flame. The quantitative formation of methane appears to explain the "equal per carbon" rule for the detector response of hydrocarbons, since all carbons are "exchanged" for methane molecules....

  20. Flaming alcoholic drinks: flirting with danger.

    Tan, Alethea; Frew, Quentin; Yousif, Ali; Ueckermann, Nicola; Dziewulksi, Peter


    Alcohol-related burn injuries carry significant mortality and morbidity rates. Flaming alcoholic beverages served in trendy bars and clubs are becoming increasingly popular. The dangers associated with an ignited alcoholic drink are often underestimated by party goers whose risk assessment ability is already impaired by heavy alcohol consumption. The authors present two cases demonstrating the varied severity of burn injuries associated with flaming alcoholic drinks, and their clinical management. Consumption of flaming alcoholic drinks poses potential risks for burn injuries. Further support is required to enable national and local agencies to implement effective interventions in drinking environments. PMID:24043236

  1. Aromatics oxidation and soot formation in flames

    Howard, J.B.; Pope, C.J.; Shandross, R.A.; Yadav, T. [Massachusetts Institute of Technology, Cambridge (United States)


    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.

  2. Three-dimensional container and cargo inspection system

    Tumer, Tumay O.; Su, Chih-Wu; Baritelle, J.; Rhoton, B.


    A fusion of two independent but complementary three- dimensional imaging techniques is proposed for detecting drugs in containers, cargo, mail and luggage. The containers, cargo, mail and/or luggage are scanned using a combined neutron and gamma ray source. A detector that can detect both neutrons and gamma rays is used to produce three dimensional images from both signals. The two images will be combined and analyzed by a fast host computer to detect drugs that may be concealed in the container, cargo and/or luggage. The two independent signatures from both neutrons and gamma rays, when analyzed simultaneously, may help determine the type of concealed material inside the containers. Containers, cargo and luggage are filled with a large variety of materials. Imaging them only in two dimensions may result in a poor contraband detection probability as different materials may shield each other. Therefore, a true three-dimensional imaging system is proposed, where the individual items inside the container or cargo can be resolved. This is expected to lead to reliable identification of the drugs even in small quantities. Such a system will also pinpoint the location of the suspected item and help expedite inspection by law enforcement agents. The proposed detection system produces two complementary three- dimensional images of the containers, cargo and/or luggage. These images are combined and analyzed by a specially developed algorithm to identify and locate the contraband automatically.

  3. Numerical simulation of autoigniting flames

    Asaithambi, Rajapandiyan; Mahesh, Krishnan


    Autoignition is highly sensitive to temperature and mixing. A density based method for DNS/LES of compressible chemically reacting flows is proposed with an explicit predictor step for advection and diffusion terms, and a semi-implicit corrector step for stiff chemical source terms. This segregated approach permits independent modification of the Navier-Stokes solver and the time integration algorithm for the chemical source term. The algorithm solves the total chemical and sensible energy equation and heat capacities of species are obtained from thermodynamic tables. Chemical mechanisms in the Chemkin format is parsed and source terms are automatically linearized allowing the ability to simulate multiple fuels with minimal effort. Validation of the algorithm is presented and results from autoigniting non-premixed flames in vitiated coflow with different fuels are discussed.

  4. Direct numerical simulations of non-premixed ethylene-air flames: Local flame extinction criterion

    Lecoustre, Vivien R.


    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.

  5. Large area x-ray detectors for cargo radiography

    Bueno, C.; Albagli, D.; Bendahan, J.; Castleberry, D.; Gordon, C.; Hopkins, F.; Ross, W.


    Large area x-ray detectors based on phosphors coupled to flat panel amorphous silicon diode technology offer significant advances for cargo radiologic imaging. Flat panel area detectors provide large object coverage offering high throughput inspections to meet the high flow rate of container commerce. These detectors provide excellent spatial resolution when needed, and enhanced SNR through low noise electronics. If the resolution is reduced through pixel binning, further advances in SNR are achievable. Extended exposure imaging and frame averaging enables improved x-ray penetration of ultra-thick objects, or "select-your-own" contrast sensitivity at a rate many times faster than LDAs. The areal coverage of flat panel technology provides inherent volumetric imaging with the appropriate scanning methods. Flat panel area detectors have flexible designs in terms of electronic control, scintillator selection, pixel pitch, and frame rates. Their cost is becoming more competitive as production ramps up for the healthcare, nondestructive testing (NDT), and homeland protection industries. Typically used medical and industrial polycrystalline phosphor materials such as Gd2O2S:Tb (GOS) can be applied to megavolt applications if the phosphor layer is sufficiently thick to enhance x-ray absorption, and if a metal radiator is used to augment the quantum detection efficiency and reduce x-ray scatter. Phosphor layers ranging from 0.2-mm to 1-mm can be "sandwiched" between amorphous silicon flat panel diode arrays and metal radiators. Metal plates consisting of W, Pb or Cu, with thicknesses ranging from 0.25-mm to well over 1-mm can be used by covering the entire area of the phosphor plate. In some combinations of high density metal and phosphor layers, the metal plate provides an intensification of 25% in signal due to electron emission from the plate and subsequent excitation within the phosphor material. This further improves the SNR of the system.

  6. The correspondence concerning fire protection regulation for operating reactors (flame test of non-flame-resistant cables)

    It is required that a flame-resistant cable should be used in the fire protection regulation demanded by the regulation about the nuclear power plant enforced in July, 2013. When we are using non-flame-resistant cables in a nuclear power plant, we need to show that it has fire-resistant capability equivalent to the capability of flame-resistant cables. For this reason, we did the vertical tray flame test and the vertical flame test using non-flame-resistant cables which applied flame-retardant coating. As a result, we checked that non-flame-resistant cables which applied flame-retardant coating had fire-resistant capability equivalent to flame-resistant cables. (author)

  7. Laminar Diffusion Flame Studies (Ground- and Space-Based Studies)

    Dai, Z.; El-Leathy, A. M.; Lin, K.-C.; Sunderland, P. B.; Xu, F.; Faeth, G. M.; Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)


    Laminar diffusion flames are of interest because they provide model flame systems that are far more tractable for analysis and experiments than more practical turbulent diffusion flames. Certainly, understanding flame processes within laminar diffusion flames must precede understanding these processes in more complex turbulent diffusion flames. In addition, many properties of laminar diffusion flames are directly relevant to turbulent diffusion flames using laminar flamelet concepts. Laminar jet diffusion flame shapes (luminous flame boundaries) have been of particular interest since the classical study of Burke and Schumann because they are a simple nonintrusive measurement that is convenient for evaluating flame structure predictions. Thus, consideration of laminar flame shapes is undertaken in the following, emphasizing conditions where effects of gravity are small, due to the importance of such conditions to practical applications. Another class of interesting properties of laminar diffusion flames are their laminar soot and smoke point properties (i.e., the flame length, fuel flow rate, characteristic residence time, etc., at the onset of soot appearance in the flame (the soot point) and the onset of soot emissions from the flame (the smoke point)). These are useful observable soot properties of nonpremixed flames because they provide a convenient means to rate several aspects of flame sooting properties: the relative propensity of various fuels to produce soot in flames; the relative effects of fuel structure, fuel dilution, flame temperature and ambient pressure on the soot appearance and emission properties of flames; the relative levels of continuum radiation from soot in flames; and effects of the intrusion of gravity (or buoyant motion) on emissions of soot from flames. An important motivation to define conditions for soot emissions is that observations of laminar jet diffusion flames in critical environments, e.g., space shuttle and space station

  8. Flame Retardant Exposures in California Early Childhood Education Environments

    Infants and young children spend as much as 50 hours per week in child care and preschool centers. Although approximately 13 million children, or 65% of all U.S. children, spend a portion of each day in early childhood education (ECE) facilities, little information is available a...

  9. Dynamics and structure of turbulent premixed flames

    Bilger, R. W.; Swaminathan, N.; Ruetsch, G. R.; Smith, N. S. A.


    In earlier work (Mantel & Bilger, 1994) the structure of the turbulent premixed flame was investigated using statistics based on conditional averaging with the reaction progress variable as the conditioning variable. The DNS data base of Trouve and Poinsot (1994) was used in this investigation. Attention was focused on the conditional dissipation and conditional axial velocity in the flame with a view to modeling these quantities for use in the conditional moment closure (CMC) approach to analysis of kinetics in premixed flames (Bilger, 1993). Two remarkable findings were made: there was almost no acceleration of the axial velocity in the flame front itself; and the conditional scalar dissipation remained as high, or higher, than that found in laminar premixed flames. The first finding was surprising since in laminar flames all the fluid acceleration occurs through the flame front, and this could be expected also for turbulent premixed flames at the flamelet limit. The finding gave hope of inventing a new approach to the dynamics of turbulent premixed flames through use of rapid distortion theory or an unsteady Bernoulli equation. This could lead to a new second order closure for turbulent premixed flames. The second finding was contrary to our measurements with laser diagnostics in lean hydrocarbon flames where it is found that conditional scalar dissipation drops dramatically below that for laminar flamelets when the turbulence intensity becomes high. Such behavior was not explainable with a one-step kinetic model, even at non-unity Lewis number. It could be due to depletion of H2 from the reaction zone by preferential diffusion. The capacity of the flame to generate radicals is critically dependent on the levels of H2 present (Bilger, et al., 1991). It seemed that a DNS computation with a multistep reduced mechanism would be worthwhile if a way could be found to make this feasible. Truly innovative approaches to complex problems often come only when there is the

  10. Distribution of electric potential in hydrocarbon flames

    Fialkov, B.S.; Shcherbakov, N.D.; Plitsyn, V.T.


    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.

  11. Theory of DDT in unconfined flames

    Khokhlov, A M; Wheeler, J C; Wheeler, J Craig


    This paper outlines a theoretical approach for predicting the onset of detonation in unconfined turbulent flames which is relevant both to problems of terrestrial combustion and to thermonuclear burning in Type Ia supernovae. Two basic assumuptions are made: 1) the gradient mechanism is the inherent mechanism that leads to DDT in unconfined conditions, and 2) the sole mechanism for preparing the gradient in induction time is by turbulent mixing and local flame quenching. The criterion for DDT is derived in terms of the one-dimensional detonation wave thickness, the laminar flame speed, and the laminar flame thickness in the reactive gas. This approach gives a lower-bound criterion for DDT for conditions where shock preheating, wall effects, and interactions with obstacles are absent. Regions in parameter space where unconfined DDT can and cannot occur are determined. A subsequent paper will address these issues specifically in the astrophysical context.

  12. Flame resistant fibrous materials. [developed from chlorofluoropolymers


    Four chlorofluoropolymer systems were developed that satisfactorily met the criteria for classification as self-extinguishing. Three of these systems consisted of Halar (a copolymer of chlorotrifluoroethylene and ethylene) and tin-based flame retardants. The fourth system was a copolymer of chlorotrifluoroethylene and tetrafluoroethylene with no flame retardants added. Production of fibers from all four candidates, by melt extrusion, was demonstrated. Fibers produced from the chlorotrifluoroethylene tetrafluoroethylene copolymer showed the most promise.

  13. Failure of cargo aileron’s actuator

    G. Zucca


    Full Text Available During a ferry flight, in a standard operation condition and at cruising level, a military cargo experienced a double hydraulic system failure due to a structural damage of the dual booster actuator. The booster actuator is the main component in mechanism of aileron’s deflection. The crew was able to arrange an emergency landing thanks to the spare oil onboard: load specialists refilled the hydraulic reservoirs. Due to safety concerns and in order to prevent the possibility of other similar incidents, a technical investigation took place. The study aimed to carry out the analysis of root causes of the actuator failure. The Booster actuator is composed mainly by the piston rod and its aluminum external case (AA7049. The assembly has two bronze caps on both ends. These are fixed in position by means of two retainers. At one end of the actuator case is placed a trunnion: a cylindrical protrusion used as a pivoting point on the aircraft. The fracture was located at one end of the case, on the trunnion side, in correspondence to the cap and over the retainer. One of the two fracture surfaces was found separated to the case and with the cap entangled inside. The fracture surfaces of the external case indicated fatigue crack growth followed by ductile separation. The failure analysis was performed by means of optical, metallographic, digital and electronic microscopy. The collected evidences showed a multiple initiation fracture mechanism. Moreover, 3D scanner reconstruction and numerical simulation demonstrated that dimensional non conformances and thermal loads caused an abnormal stress concentration. Stress concentration was located along the case assy outer surface where the fatigue crack originated. The progressive rupture mechanism grew under cyclical axial load due to the normal operations. Recommendations were issued in order to improve dimensional controls and assembly procedures during production and overhaul activities.

  14. Quantitative Species Measurements In Microgravity Combustion Flames

    Chen, Shin-Juh; Pilgrim, Jeffrey S.; Silver, Joel A.; Piltch, Nancy D.


    The capability of models and theories to accurately predict and describe the behavior of low gravity flames can only be verified by quantitative measurements. Although video imaging, simple temperature measurements, and velocimetry methods have provided useful information in many cases, there is still a need for quantitative species measurements. Over the past decade, we have been developing high sensitivity optical absorption techniques to permit in situ, non-intrusive, absolute concentration measurements for both major and minor flames species using diode lasers. This work has helped to establish wavelength modulation spectroscopy (WMS) as an important method for species detection within the restrictions of microgravity-based measurements. More recently, in collaboration with Prof. Dahm at the University of Michigan, a new methodology combining computed flame libraries with a single experimental measurement has allowed us to determine the concentration profiles for all species in a flame. This method, termed ITAC (Iterative Temperature with Assumed Chemistry) was demonstrated for a simple laminar nonpremixed methane-air flame at both 1-g and at 0-g in a vortex ring flame. In this paper, we report additional normal and microgravity experiments which further confirm the usefulness of this approach. We also present the development of a new type of laser. This is an external cavity diode laser (ECDL) which has the unique capability of high frequency modulation as well as a very wide tuning range. This will permit the detection of multiple species with one laser while using WMS detection.

  15. Sensing flame structure by process tomography.

    Liu, Jing; Liu, Shi; Zhou, Wanting; Qi, Xin; Lei, Jing; Mu, Huaiping


    Non-intrusive visualization of the structure of flames can offer us many advantages in studying the reaction mechanisms of combustion and observing special distributions of the parameters required for the development of equipment such as jet engines and gas turbines. Process tomography is a relatively new technique for such a task, but is useful owing to its fast speed and capability of detecting signals related to ionizations caused by chemical reactions and thermal effects. Electric capacitance tomography (ECT) is one of the process tomographic techniques. ECT usually comprises a sensor array of electrodes that detect permittivity variations in the measuring zone, a data-logging device and a computer that controls data acquisition and carries out image reconstruction. There have been studies on ECT imaging of flames; however, ECT has not been exploited sufficiently to reveal the inner structure of the flames. In this study, a sensor with planar electrodes is created, and the associated three-dimensional sensitivity map is generated by the finite-element method to detect flame structure. A series of experiments are carried out covering a range of feed rates of fuel and air. Data are collected by the ECT sensor and hardware. The results of the ECT reconstruction show good agreement with actual features, and the structure of the flame is found. This opens up a new route for the study of flames. This article is part of the themed issue 'Supersensing through industrial process tomography'. PMID:27185962

  16. On-Shell Description of Stationary Flames

    Kazakov, K A


    The problem of non-perturbative description of stationary flames with arbitrary gas expansion is considered. On the basis of the Thomson circulation theorem an implicit integral of the flow equations is constructed. With the help of this integral, a simple explicit expression for the vortex mode of the burnt gas flow near the flame front is obtained. Furthermore, a dispersion relation for the potential mode at the flame front is written down, thus reducing the initial system of bulk equations and jump conditions for the flow variables to a set of integro-differential equations for the flame front position and the flow velocity at the front. The developed approach is applied to the case of zero-thickness flames. An equation accounting the transfer processes in the flame front is also obtained. Finally, an asymptotic expansion of the derived equations is carried out in the case \\theta\\to 1 where \\theta is the gas expansion coefficient, and a single equation for the front position is obtained in the first post-S...

  17. Quantitative Species Measurements in Microgravity Combustion Flames

    Silver, Joel A.; Wood, William R.; Chen, Shin-Juh; Dahm, Werner J. A.; Piltch, Nancy D.


    Flame-vortex interactions are canonical configurations that can be used to study the underlying processes occurring in complicated turbulent reacting flows. The elegant simplicity of the flame-vortex interaction permits the study of these complex interactions under relatively controllable experimental configurations, in contrast to direct measurements in turbulent flames. The ability to measure and model the fundamental phenomena that occur in a turbulent flame, but with time and spatial scales which are amenable to our diagnostics, permits significant improvements in the understanding of turbulent combustion under both normal and reduced gravity conditions. In this paper, we report absolute mole fraction measurements of methane in a reacting vortex ring. These microgravity experiments are performed in the 2.2-sec drop tower at NASA Glenn Research Center. In collaboration with Drs. Chen and Dahm at the University of Michigan, measured methane absorbances are incorporated into a new model from which the temperature and concentrations of all major gases in the flame can be determined at all positions and times in the development of the vortex ring. This is the first demonstration of the ITAC (Iterative Temperature with Assumed Chemistry) approach, and the results of these computations and analyses are presented in a companion paper by Dahm and Chen at this Workshop. We believe that the ITAC approach will become a powerful tool in understanding a wide variety of combustion flames under both equilibrium and non-equilibrium conditions.

  18. NO concentration imaging in turbulent nonpremixed flames

    Schefer, R.W. [Sandia National Laboratories, Livermore, CA (United States)


    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.

  19. Spectroscopic neutron radiography for a cargo scanning system

    Rahon, Jill; Danagoulian, Areg; MacDonald, Thomas D.; Hartwig, Zachary S.; Lanza, Richard C.


    Detection of cross-border smuggling of illicit materials and contraband is a challenge that requires rapid, low-dose, and efficient radiographic technology. The work we describe here is derived from a technique which uses monoenergetic gamma rays from low energy nuclear reactions, such as 11B(d,nγ)12C, to perform radiographic analysis of shipping containers. Transmission ratios of multiple monoenergetic gamma lines resulting from several gamma producing nuclear reactions can be employed to detect materials of high atomic number (Z), the details of which will be described in a separate paper. Inherent in this particular nuclear reaction is the production of fast neutrons which could enable neutron radiography and further characterization of the effective-Z of the cargo, especially within the range of lower Z. Previous research efforts focused on the use of total neutron counts in combination with X-ray radiography to characterize the hydrogenous content of the cargo. We present a technique of performing transmitted neutron spectral analysis to reconstruct the effective Z and potentially the density of the cargo. This is made possible by the large differences in the energy dependence of neutron scattering cross-sections between hydrogenous materials and those of higher Z. These dependencies result in harder transmission spectra for hydrogenous cargoes than those of non-hydrogenous cargoes. Such observed differences can then be used to classify the cargo based on its hydrogenous content. The studies presented in this paper demonstrate that such techniques are feasible and can provide a contribution to cargo security, especially when used in concert with gamma radiography.

  20. Monte-Carlo simulations of neutron-induced activation in a Fast-Neutron and Gamma-Based Cargo Inspection System

    Bromberger, B.; Bar, D.; Brandis, M.; Dangendorf, V.; Goldberg, M. B.; Kaufmann, F.; Mor, I.; Nolte, R.; Schmiedel, M.; Tittelmeier, K.; Vartsky, D.; Wershofen, H.


    An air cargo inspection system combining two nuclear reaction based techniques, namely Fast-Neutron Resonance Radiography and Dual-Discrete-Energy Gamma Radiography is currently being developed. This system is expected to allow detection of standard and improvised explosives as well as special nuclear materials. An important aspect for the applicability of nuclear techniques in an airport inspection facility is the inventory and lifetimes of radioactive isotopes produced by the neutron radiation inside the cargo, as well as the dose delivered by these isotopes to people in contact with the cargo during and following the interrogation procedure. Using MCNPX and CINDER90 we have calculated the activation levels for several typical inspection scenarios. One example is the activation of various metal samples embedded in a cotton-filled container. To validate the simulation results, a benchmark experiment was performed, in which metal samples were activated by fast-neutrons in a water-filled glass jar. The induced activity was determined by analyzing the gamma spectra. Based on the calculated radioactive inventory in the container, the dose levels due to the induced gamma radiation were calculated at several distances from the container and in relevant time windows after the irradiation, in order to evaluate the radiation exposure of the cargo handling staff, air crew and passengers during flight. The possibility of remanent long-lived radioactive inventory after cargo is delivered to the client is also of concern and was evaluated.

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


    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.

  2. The Linear Instability of Astrophysical Flames in Magnetic Fields

    Dursi, L J


    Supernovae of Type Ia are used as standard candles for cosmological observations despite the as yet incomplete understanding of their explosion mechanism. In one model, these events are thought to result from subsonic burning in the core of an accreting Carbon/Oxygen white dwarf that is accelerated through flame wrinkling and flame instabilities. Many such white dwarfs have significant magnetic fields. Here we derive the linear effects of such magnetic fields on one flame instability, the well-known Landau-Darrieus instability. When the magnetic field is strong enough that the flame is everywhere sub-Alfvenic, the instability can be greatly suppressed. Super-Alfvenic flames are much less affected by the field, with flames propagating parallel to the field somewh at destabilized, and flames propagating perpendicular to the field somewhat stabili zed. Trans-Alfvenic parallel flames, however, like trans-Alfvenic parallel shocks, are seen to be non-evolutionary; understanding the behavior of these flames will req...

  3. Laminar and Turbulent Gaseous Diffusion Flames. Appendix C

    Faeth, G. M.; Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)


    Recent measurements and predictions of the properties of homogeneous (gaseous) laminar and turbulent non-premixed (diffusion) flames are discussed, emphasizing results from both ground- and space-based studies at microgravity conditions. Initial considerations show that effects of buoyancy not only complicate the interpretation of observations of diffusion flames but at times mislead when such results are applied to the non-buoyant diffusion flame conditions of greatest practical interest. This behavior motivates consideration of experiments where effects of buoyancy are minimized; therefore, methods of controlling the intrusion of buoyancy during observations of non-premixed flames are described, considering approaches suitable for both normal laboratory conditions as well as classical microgravity techniques. Studies of laminar flames at low-gravity and microgravity conditions are emphasized in view of the computational tractability of such flames for developing methods of predicting flame structure as well as the relevance of such flames to more practical turbulent flames by exploiting laminar flamelet concepts.

  4. Preparation of Flame Retardant Modified with Titanate for Asphalt Binder

    Bo Li


    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.

  5. A Computational Investigation of Sooting Limits of Spherical Diffusion Flames

    Lecoustre, V. R.; Chao, B. H.; Sunderland, P. B.; Urban, D. L.; Stocker, D. P.; Axelbaum, R. L.


    Limiting conditions for soot particle inception in spherical diffusion flames were investigated numerically. The flames were modeled using a one-dimensional, time accurate diffusion flame code with detailed chemistry and transport and an optically thick radiation model. Seventeen normal and inverse flames were considered, covering a wide range of stoichiometric mixture fraction, adiabatic flame temperature, and residence time. These flames were previously observed to reach their sooting limits after 2 s of microgravity. Sooting-limit diffusion flames with residence times longer than 200 ms were found to have temperatures near 1190 K where C/O = 0.6, whereas flames with shorter residence times required increased temperatures. Acetylene was found to be a reasonable surrogate for soot precursor species in these flames, having peak mole fractions of about 0.01.

  6. 46 CFR 151.05-2 - Compliance with requirements for tank barges carrying benzene and benzene containing cargoes, or...


    ... benzene and benzene containing cargoes, or butyl acrylate cargoes. 151.05-2 Section 151.05-2 Shipping... Compliance with requirements for tank barges carrying benzene and benzene containing cargoes, or butyl acrylate cargoes. A tank barge certificated to carry benzene and benzene containing cargoes or...

  7. The Effects of Gravity on Wrinkled Laminar Flames

    Kostiuk, Larry W.; Zhou, Liming; Cheng, Robert K.


    The effects of gravity are significant to the dynamics of idealized unconfined open premixed flames. Moderate to low turbulence Reynolds number flames, i.e., wrinkled laminar flames, of various unconfined geometries have been used extensively for investigating fundamental processes of turbulent flame propagation and to validate theoretical models. Without the wall constraints, the flames are free to expand and interact with surrounding ambient air. The flow field in which the flame exists is determined by a coupling of burner geometry, flame orientation and the gravity field. These complex interactions raise serious questions regarding the validity of comparing the experimental data of open flames with current theoretical and numerical models that do not include the effects of gravity nor effects of the larger aerodynamic flowfield. Therefore, studies of wrinkled laminar flame in microgravity are needed for a better understanding of the role of gravity on flame characteristics such as the orientation, mean aerodynamics stretch, flame wrinkle size and burning rate. Our approach to characterize and quantify turbulent flame structures under microgravity is to exploit qualitative and quantitative flow visualization techniques coupled with video recording and computer controlled image analysis technologies. The experiments will be carried out in the 2.2 second drop tower at the NASA Lewis Research Center. The longest time scales of typical wrinkled laminar flames in the geometries considered here are in the order of 10 msec. Hence, the duration of the drop is sufficient to obtain the amount of statistical data necessary for characterize turbulent flame structures.

  8. Gravitational effects on the structure and propagation of premixed flames

    Hamins, A.; Heitor, M.; Libby, P. A.

    The influence of gravity on the propagation velocity and shape of premixed laminar flames is studied experimentally over the entire flammability range of methane-air mixtures. In the experiments reported here a vertical tube 10 cm dia, closed on both ends and open in the middle is filled with reactants and ignited in its central plane so that flames propagate in both the upward and downward directions. Additional experiments are made in a vertical tube 5 cm dia with flames propagating from an open towards a closed end. Steady flame propagation is achieved over the entire range of equivalence ratios by locating a series of holes along the length of the tubes covered with a thin film which is vaporized by the passage of the flame. Measurements in the larger tube indicate that gravity affects both rich and lean laminar flames in that upward propagating flames are faster than downward. The shape of the flames is complex with the former roughly hemispherical, the latter flat but with a cellular structure. In near stoichiometric mixtures the flames are oscillatory, are unaffected by gravity and correspond to weakly turbulent flames. The results in the smaller tube indicate that upward moving flames propagate faster than downward moving flames over the entire range of equivalence ratios studied and that the flame shape is always hemispherical. The preliminary results for turbulent premixed flames propagating upward and downward are discussed.

  9. Characteristics of Non-Premixed Turbulent Flames in Microgravity

    Hegde, U.; Yuan, Z. G.; Stocker, D. P.; Bahadori, M. Y.


    This project is concerned with the characteristics of turbulent hydrocarbon (primarily propane) gas-jet diffusion flames in microgravity. A microgravity environment provides the opportunity to study the structure of turbulent diffusion flames under momentum-dominated conditions (large Froude number) at moderate Reynolds number which is a combination not achievable in normal gravity. This paper summarizes progress made since the last workshop. Primarily, the features of flame radiation from microgravity turbulent jet diffusion flames in a reduced gravity environment are described. Tests were conducted for non-premixed, nitrogen diluted propane flames burning in quiescent air in the NASA Glenn 5.18 Second Zero Gravity Facility. Measured flame radiation from wedge-shaped, axial slices of the flame are compared for microgravity and normal gravity flames. Results from numerical computations of the flame using a k-e model for the turbulence are also presented to show the effects of flame radiation on the thermal field. Flame radiation is an important quantity that is impacted by buoyancy as has been shown in previous studies by the authors and also by Urban et al. It was found that jet diffusion flames burning under microgravity conditions have significantly higher radiative loss (about five to seven times higher) compared to their normal gravity counterparts because of larger flame size in microgravity and larger convective heat loss fraction from the flame in normal gravity. These studies, however, were confined to laminar flames. For the case of turbulent flames, the flame radiation is a function of time and both the time-averaged and time-dependent components are of interest. In this paper, attention is focused primarily on the time-averaged level of the radiation but the turbulent structure of the flame is also assessed from considerations of the radiation power spectra.

  10. On the dynamics of flame edges in diffusion-flame/vortex interactions

    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)


    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)