Science.gov

Sample records for 1-3 perfluorinated fused

  1. Short and general procedure for synthesizing cis-1,2-fused 1,3-oxathiolan-, 1,3-oxaselenolan-, and 1,3-oxazolidin-2-imine carbohydrate derivatives.

    PubMed

    Castilla, Javier; Marín, Irene; Matheu, M Isabel; Díaz, Yolanda; Castillón, Sergio

    2010-01-15

    Novel cis-1,2-fused 1,3-oxathiolan-, 1,3-oxaselenolan-, and 1,3-oxazolidin-2-imine carbohydrate derivatives have been prepared by treatment of the corresponding 1,2-anhydrosugars with potassium thiocyanate, potassium selenocyanate, and sodium cyanamide, respectively. The procedure is compatible with several protecting groups such as acyl, benzyl, and silyl and also with sugars of different configurations.

  2. Perfluorinated Compounds

    EPA Science Inventory

    Perfluorinated compounds such as the perfluoroalkyl acids (PFAAs) and their derivatives are important man-made chemicals that have wide consumer and industrial applications. They are relatively contemporary chemicals, being in use only since the 1950s, and until recently, have be...

  3. A novel protocol for the facile construction of tetrahydroquinoline fused tricyclic frameworks via an intramolecular 1,3-dipolar nitrile oxide cycloaddition reaction.

    PubMed

    Bakthadoss, Manickam; Vinayagam, Varathan

    2015-10-21

    An efficient method towards the synthesis of quinoline fused tricyclic compounds involving an intramolecular 1,3-dipolar nitrile oxide cycloaddition reaction utilizing Baylis-Hillman derivatives in good yields has been described for the first time. A highly functionalized tricyclic framework was created by forming two rings and two adjacent stereocentres through the formation of two N-C bonds, one C-C bond and one O-C bond in a highly regio and diastereoselective manner.

  4. Human cancer cell line based approach of 1,3,4-thiadiazole and its fused ring: A comprehensive review.

    PubMed

    Raj, Vinit; Rai, Amit; Saha, Sudipta

    2016-10-13

    The chemistry of heterocyclic containing, 1,3,4-thiadiazole has been an interesting field of study from ancient years. Subsequently, 1,3,4-thiadiazole nucleus constitutes a significant class of compounds for new drug development. Recently, various 1,3,4-thiadiazole derivatives have been synthesized and evaluated their biological activities including antimicrobial, antituberculosis, antioxidant, anti-inflammatory, anticonvulsants, antidepressant and anxiolytic, antihypertensive, anticancer and antifungal activity. The search for anticancer compounds with more selective activity and lower side effect continue to be an active area of argument examination in medicinal chemistry. This review is elaborately described the medicinal chemistry, their structural activity relationship and anticancer properties with respect to human cell line based approach related to synthesized 1,3,4-thiadiazole derivatives.

  5. A synthesis of fused acenaphthopyrrolizines via the 1,3-dipolar cycloaddition reaction of azomethine ylides with acetylenic esters.

    PubMed

    Yavari, Issa; Baoosi, Leila; Halvagar, Mohammad R

    2017-01-13

    An efficient synthesis of tetraalkyl 6a-hydroxy-3-alkyl-3H,6aH-acenaphtho[1,2-g] pyrrolizine-1,2,5,6-tetracarboxylates via the 1,3-dipolar cycloaddition reaction of azomethine ylides (generated in situ from [Formula: see text]-amino acids and acenaphthylene-1,2-dione) with dialkyl acetylenedicarboxylates is described. When glycine was used instead of alanine, phenylalanine, valine, or isoleucine, dialkyl (E)-1[Formula: see text]-(1,4-dialkoxy-1,4-dioxobut-2-en-2-yl)-2-oxo-[Formula: see text],5[Formula: see text]-dihydro-2H-spiro [acenaphthylene-1,2[Formula: see text]-pyrrole]-3[Formula: see text],4[Formula: see text]-dicarboxylates were obtained. The steric effects of the [Formula: see text]-amino acids side chains may be responsible for their different behaviors.

  6. PERSISTENT PERFLUORINATED ORGANIC COMPOUNDS

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have gained notoriety in the recent past. Global distribution of PFCs in wildlife, environmental samples and humans has sparked a recent increase in new investigations concerning PFCs. Historically PFCs have been used in a wide variety of consume...

  7. Preparation of Perfluorinated Imidoylamidoxime Polymers

    NASA Technical Reports Server (NTRS)

    Rosser, R. W.; Kratzer, R. H.; Paciorek, K. J. L.; Ito, T. I.

    1982-01-01

    Perfluorinated imidoylamidoxime polymers with excellent resistance to heat, chemicals and solvents are prepared by condensing a perfluorinated nitrile with a perfluorinated amidoxime in vacuum or inert atmosphere from 20 degrees to 70 degrees C. When both reactants are difunctional, oligomeric or polymeric products are obtained. After cyclization of imidoylamidoxime groups to 1,2,4-oxadiazole linkages, process yields highly resistant elastomers. Competing side reactions are inhibited by low processing temperature.

  8. Nickel(II)-Catalyzed Cascade Vinylogous Mukaiyama 1,6-Michael/Michael Addition of 2-Silyloxyfuran with N-Sulfonyl-1-aza-1,3-dienes: Access to Fused Piperidine/Butyrolactone Skeletons.

    PubMed

    Liu, Kang; Chang, Xin; Wang, Chun-Jiang

    2016-12-16

    An unprecedented and highly efficient nickel-catalyzed cascade vinylogous Mukaiyama 1,6-Michael/Michael addition of 2-silyloxyfuran with N-sulfonyl-1-aza-1,3-dienes is reported, in which 2-silyloxyfuran was successfully employed as nucleophile and electrophile sequentially. This methodology combined with subsequent reduction provides a facile access to biologically important fused piperidine/butyrolactone skeletons in good yield with exclusive diastereoselectivity under mild reaction conditions.

  9. Regio- and stereoselective synthesis of pregnane-fused isoxazolines by nitril-oxide/alkene 1,3-dipolar cycloaddition and an evaluation of their cell-growth inhibitory effect in vitro

    NASA Astrophysics Data System (ADS)

    Mótyán, Gergő; Baji, Ádám; Zupkó, István; Frank, Éva

    2016-04-01

    Efficient syntheses of some pregnane-fused isoxazolines from 16-dehydropregnenolone acetate with different arylnitrile oxides were carried out by 1,3-dipolar cycloadditions. The intermolecular ring-closures occurred in a highly regio- and stereoselective manner permitting the formation of a single 16α,17α-condensed diastereomer in which the O terminus of the nitrile oxide dipole is attached to C-17 of the sterane core. The conversions were found to be affected significantly by the electronic character of the substituents on the aromatic moiety of the 1,3-dipoles. Deacetylation of the primary products resulted in the corresponding 3β-OH analogs. All of the synthesized compounds were subjected to in vitro pharmacological studies for the determination of their antiproliferative effects on four breast cancer cell lines (MCF7, T47D, MDA-MB-231 and MDA-MB-361).

  10. Application of a radial-flow bioreactor in the production of beta1,3-N-acetylglucosaminyltransferase-2 fused with GFPuv using stably transformed insect cell lines.

    PubMed

    Kwon, Mi Sun; Kato, Tatsuya; Dojima, Takashi; Park, Enoch Y

    2005-08-01

    An RFB (radial-flow bioreactor) with a reactor volume of 5 ml was applied to produce human beta3GnT (beta1,3-N-acetylglucosaminyltransferase) using two stably transformed insect cell lines. When air was supplied to the RFB, cell growth stopped at 4 days of culture and beta3GnT was not detected. However, with a supply of pure oxygen, the cell concentration, assumed from glucose consumption, increased by 1.3x10(7) cells/ml. Insect cells attached to poly(vinyl alcohol) matrixes packed in the RFB and grew confluently; 5.6 m-units/ml beta3GnT was produced under the conditions of pure oxygen supply and addition of glucose and glutamine. This RFB was first applied in beta3GnT production using stably transformed insect cells. The amount of beta3GnT production in only a 5 ml-scale RFB was comparable with that of a 100 ml shaking flask culture.

  11. Direct formation of ring-fused 1,3-thiazine-2,4-dithiones from aromatic o-amino carboxylic acids: observation of a carbon disulfide mediated thionation.

    PubMed

    Ottersbach, Philipp A; Elsinghorst, Paul W; Häcker, Hans-Georg; Gütschow, Michael

    2010-08-20

    A facile synthesis of 2H-3,1-benzothiazine-2,4(1H)-dithiones (trithioisatoic anhydrides) or 2H-naphtho[2,3-d][1,3]thiazine-2,4(1H)-dithione solely from anthranilic acids or 3-amino-2-naphthoic acid and carbon disulfide, performed at room temperature in 1,4-dioxane in the presence of Et(3)N, is reported. Corresponding 2-alkylsulfanyl derivatives were obtained in one-pot reactions under the same conditions after addition of alkyl halides. The mechanism of the thiazine cyclization was investigated using (13)C-labeled carbon disulfide to reveal that carbon disulfide was incorporated into the heterocycle and additionally acted as a thionation reagent.

  12. Thermally Stable Perfluorinated Polymers.

    DTIC Science & Technology

    Studies of the poly(perfluoroalkylene-1,3,4- oxadiazole ) systems have been continued using the following monomers: 1,3-bis(5-tetrazolys...perfluoropropane; 1,8-bis(5-tetrazolyl) perfluorooctane; bitetrazole; perfluorosebacoyl chloride; 5,5’-bis(n-perfluorobutyryl) chloride)-2,2’-bi-1,3,4- oxadiazole ... oxadiazole rings; attempts were made to form a polymer incorporating 1,2,4-oxidiazole linkages. Syntheses have been carried out which gave new monomers containing triazole rings. (Author).

  13. Brominated Flame Retardants and Perfluorinated Chemicals

    EPA Science Inventory

    Brominated flame retardants (BFRs) and perfluorinated chemicals (PFCs) belong to a large class of chemicals known as organohalogens. It is believed that both BFRs and PFCs saved lives by reducing flammability of materials commonly used and bactericidal (biocidal) properties. Thes...

  14. Perfluorinated Compounds In The Ohio River Basin

    EPA Science Inventory

    Contaminants of emerging concern (CECs) in waterways include pharmaceuticals and personal care products (PPCPs), alkylphenols, endocrine disrupting chemicals (EDCs) and perfluorinated alkyl compounds (PFCs). Their distributions and persistence in the aquatic environment remain p...

  15. Formation of Fused-Ring 2′-Deoxycytidine Adducts from 1-Chloro-3-buten-2-one, an in Vitro 1,3-Butadiene Metabolite, under in Vitro Physiological Conditions

    PubMed Central

    Sun, Liang; Pelah, Avishay; Zhang, Dong-Ping; Zhong, Yu-Fang; An, Jing; Yu, Ying-Xin; Zhang, Xin-Yu; Elfarra, Adnan A.

    2013-01-01

    1-Chloro-3-buten-2-one (CBO) is a potential metabolite of 1,3-butadiene (BD), a carcinogenic air pollutant. CBO is a bifunctional alkylating agent that readily reacts with glutathione (GSH) to form mono-GSH and di-GSH adducts. Recently, CBO and its precursor 1-chloro-2-hydroxy-3-butene (CHB) were found to be cytotoxic and genotoxic in human liver cells in culture with CBO being approximately 100-fold more potent than CHB. In the present study, CBO was shown to react readily with 2′-deoxycytidine (dC) under in vitro physiological conditions (pH 7.4, 37 °C) to form four dC adducts with the CBO moieties forming fused rings with the N3 and N4 atoms of dC. The four products were structurally characterized as 2-hydroxy-2-hydroxymethyl-7-(2-deoxy-β-D-erythro-pentofuranosyl)-1,2,3,4-tetrahy dro-6-oxo-6H,7H-pyrimido[1,6-a]pyrimidin-5-ium (dC-1 and dC-2, a pair of diastereomers), 4-chloromethyl-4-hydroxy-7-(2-deoxy-β-D-erythro-pentofuranosyl)-1,2,3,4-tetrahydr o-6-oxo-6H,7H-pyrimido[1,6-a]pyrimidin-5-ium (dC-3), and 2-chloromethyl-2-hydroxy-7-(2-deoxy-β-D-erythro-pentofuranosyl)-1,2,3,4-tetrahydr o-6-oxo-6H,7H-pyrimido[1,6-a]pyrimidin-5-ium (dC-4). Interestingly, dC-1 and dC-2 were stable under our experimental conditions (pH 7.4, 37 °C, 6 h) and existed in equilibrium as indicated by HPLC analysis, whereas dC-3 and dC-4 were labile with the half-lives being 3.0 ± 0.36 and 1.7 ± 0.06 h, respectively. Decomposition of dC-4 produced both dC-1 and dC-2, whereas acid hydrolysis of dC-1/dC-2 and dC-4 in 1 M HCl at 100 °C for 30 min yielded the deribosylated adducts dC-1H/dC-2H and dC-4H, respectively. Because fused-ring dC adducts of other chemicals are mutagenic, the characterized CBO-dC adducts could be mutagenic and play a role in the cytotoxicity and genotoxicity of CBO and its precursors, CHB and BD. The CBO-dC adducts may also be used as standards to characterize CBO-DNA adducts and to develop potential biomarkers for CBO formation in vivo. PMID:24020501

  16. 40 CFR 721.10516 - Perfluorinated alkylthio betaine (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Perfluorinated alkylthio betaine... Specific Chemical Substances § 721.10516 Perfluorinated alkylthio betaine (generic). (a) Chemical substance... perfluorinated alkylthio betaine (PMN P-10-405) is subject to reporting under this section for the...

  17. 40 CFR 721.10516 - Perfluorinated alkylthio betaine (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Perfluorinated alkylthio betaine... Specific Chemical Substances § 721.10516 Perfluorinated alkylthio betaine (generic). (a) Chemical substance... perfluorinated alkylthio betaine (PMN P-10-405) is subject to reporting under this section for the...

  18. Anionic Derivatives of Perfluorinated Trimethylgold.

    PubMed

    Menjón, Babil; Pérez-Bitrián, Alberto; Martínez-Salvador, Sonia; Baya, Miguel; Casas, José María; Martín, Antonio; Orduna, Jesús

    2017-03-20

    The homoleptic compound [PPh₄][CF₃AuCF₃] cleanly undergoes photoinduced oxidative addition of CF₃I to afford the organogold(III) derivative [PPh₄][(CF₃)₃AuI] in good yield and under mild conditions. This compound provides a convenient entry to the chemistry of the perfluorinated (CF₃)₃Au fragment whose properties are analyzed with the aid of DFT methods and compared with those of the homologous non-fluorinated (CH₃)₃Au moiety. It is found that reductive elimination of CX₃-CX₃ in the former (X = F) requires a much higher energy barrier than in the latter (X = H) and is therefore considerably less favored. This can be considered as one of the main features underlying the significantly higher stability associated to the (CF₃)₃Au fragment and its derivatives. This unsaturated, 14-electron species can be stabilized by coordination of any of the halide ligands, including fluoride. In fact, the whole series of anionic [PPh₄][(CF₃)₃AuX] complexes (X = F, Cl, Br, I, CN) has now been isolated and conveniently characterized. Evidence for intermolecular decomposition pathways upon thermolysis in the condensed phase is presented.

  19. Superhydrophobic perfluorinated metal-organic frameworks.

    PubMed

    Chen, Teng-Hao; Popov, Ilya; Zenasni, Oussama; Daugulis, Olafs; Miljanić, Ognjen Š

    2013-08-07

    Three perfluorinated Cu-based metal-organic frameworks (MOFs) were prepared starting from extensively fluorinated biphenyl-based ligands accessed via C-H functionalization. These new materials are highly hydrophobic: with water contact angles of up to 151 ± 1°, they are among the most water-repellent MOFs ever reported.

  20. PERFLUORINATED ORGANIC COMPOUND EXPOSURE ASSESSMENT RESEARCH

    EPA Science Inventory

    A wide range of perfluorinated organic compounds (PFCs) has been used in a variety of industrial processes and consumer products. The most commonly studied PFCs include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), but there are many more compounds in this c...

  1. (CHINA) PERFLUORINATED ORGANIC COMPOUND EXPOSURE ASSESSMENT RESEARCH

    EPA Science Inventory

    A wide range of perfluorinated organic compounds (PFCs) has been used in a variety of industrial processes and consumer products. The most commonly studied PFCs include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), but there are many more compounds in this c...

  2. Effects of perfluorinated chemicals on adipocyte development

    EPA Science Inventory

    Obesity is a growing concern in the US population. Current interest is high in the role played by environmental factors called obesogens that may contribute to obesity through developmental exposure. One class of potential obesogens is the family of perfluorinated chemicals used ...

  3. Perfluorinated Compounds: Emerging POPs with Potential Immunotoxicity

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have been recognized as an important class of environmental contaminants commonly detected in blood samples of both wildlife and humans. These compounds have been in use for more than 60 years as surface treatment chemicals, polymerization aids, an...

  4. Cellular Effects of Perfluorinated Fatty Acids.

    DTIC Science & Technology

    1985-01-01

    TCDD appeared to interfere with fatty acid metabolism leading to an increase in unsaturation. Furthermore, Andersen et al. (2) proposed that such an...increase in cellular unsaturated fatty acids may lead-to excessive membrane fluidity (as indicated by induced changes in red blood cell fragility) and...TASK WORK UNITELEMENT NO. NO. NO. NO. 11. TITLE (include Security Claificati on) ~/~. Cellular Effects of Perfluorinated Fatty Ac ds 12. PERSONAL

  5. 21 CFR 173.21 - Perfluorinated ion exchange membranes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Perfluorinated ion exchange membranes. 173.21... Polymer Adjuvants for Food Treatment § 173.21 Perfluorinated ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in...

  6. Novel synthesis of a series of spiro 1,3-indanedione-fused dihydropyridines through the condensation of a tetrone with N-aryl/alkylenamines in presence of solid support silica sulfuric acid.

    PubMed

    Kundu, Ashis; Pramanik, Animesh

    2015-08-01

    A convenient protocol for the library synthesis of biologically important 1-aryl-2',6-spiro(1',3'-indanedione)-1H-indeno[1,2-b]quinoline-5,7-diones has been developed. In this one-pot reaction protocol a tetrone is condensed with various N-aryl/alkylenamines of 1,3-cyclohexadiones on the surface of a solid-supported acid catalyst silica sulfuric acid under solvent-free condition. The significant advantages of this methodology are the use of solvent-free reaction conditions, operational simplicity of the reaction, good yield of the products with high atom economy, and employment of a recyclable catalyst. All these favorable factors make the present method convenient, economic, and 'benign by design'.

  7. Effects of perfluorinated chemicals on adipocyte development ...

    EPA Pesticide Factsheets

    Obesity is a growing concern in the US population. Current interest is high in the role played by environmental factors called obesogens that may contribute to obesity through developmental exposure. One class of potential obesogens is the family of perfluorinated chemicals used as surfactants in a variety of industrial applications. Given the importance of understanding the role these compounds play in lipid homeostasis we used pre-adipocyte 3T3-L1 mouse fibroblast cells (Zen-Bio, RTP NC) to study their effects on adipogenesis and lipid accumulation. These cells differentiate into adipocytes accumulating large lipid droplets. Cultures were treated with perfluorooctanoic acid (PFOA) (1-200uM), perfluorononanoic acid (PFNA) (5-lOOuM), perfluorooctane sulfonate (PFOS) (5O-300uM), and perfluorohexane sulfonate (PFHxS) (40- 250uM). Cell size number, and lipid content were assessed using morphomeiric analysis. All four compounds decreased cell size compared to control, and PFNA was most potent, in terms of lowest observed effect concentration (LOEC), whereas PFOA was least potent. Cell number increased for all perfluorinated chemicals tested, most potently for PFNA and least for PFOS. Interestingly, average lipid area per cell for all four chemicals decreased compared to control, but PFOS and PFHxS had increased total lipid area. Additionally, significant increases in total triglyceride were noted for all compounds compared to controls. PFOA and PFNA increased trigly

  8. Features of ion transport in perfluorinated ion-exchange membranes

    SciTech Connect

    Timashev, S.F.

    1986-02-01

    The conditions for functioning for various systems and devices electrolyzers for ''chlorate'' electrolysis, current sources, etc.) with perfluorinated ion-exchange membranes and septums are determined to a considerable degree by the physicochemical properties of the perfluorinated materials. In this work, on the basis of concepts developed in streaming theory as to the topology of the ''infinite clusters'' (ICs), the author defines more precisely the form of the preexponential dependence of ion transport coefficients and draws conclusions on the character of heat evolution in a perfluorinated membrane when an electric current is passed through the membrane.

  9. Developmental Toxicity of Perfluorinated Phosphonic Acids in Mice

    EPA Science Inventory

    Perfluorinated phosphonic acids (PFPAs) are a third member of the perfluoroalkyl acid (PFAA) family, and are structurally similar to the perfluoroalkyl sulfonates and perfluoroalkyl carboxylates. PFPAs are used primarily as a surfactant defoaming agent in pesticide production. Re...

  10. Perfluorinated Alkyl Compounds: Challenges To Develop Robust And Reliable Methods

    EPA Science Inventory

    An increasing number of studies have been conducted to investigate the environmental distribution of perfluorinated alkyl compounds (PFCs), some of which are known to be toxic in laboratory studies. Despite growing public concerns, environmental monitoring data are still limited...

  11. ANALYSIS OF PERFLUORINATED CARBOXYLIC ACIDS IN SOILS II: OPTIMIZATION OF CHROMATOGRAPHY AND EXTRACTION

    EPA Science Inventory

    With the objective of detecting and quantitating low concentrations of perfluorinated carboxylic acids (PFCAs), including perfluorinated octanoic acid (PFOA), in soils, we compared the analytical suitability of liquid chromatography columns containing three different stationary p...

  12. ANALYSIS OF PERFLUORINATED CARBOXYLIC ACIDS IN SOILS: DETECTION AND QUANTITATION ISSUES AT LOW CONCENTRATIONS

    EPA Science Inventory

    Methods were developed for the extraction from soil, identification, confirmation and quantitation by LC/MS/MS of trace levels of perfluorinated octanoic acid (PFOA), perfluorinated nonanoic acid (PFNA) and perfluorinated decanoic acid (PFDA). Whereas PFOA, PFNA and PFDA all can...

  13. Perfluorinated compounds in food: a global perspective.

    PubMed

    Picó, Yolanda; Farré, Marinella; Llorca, Marta; Barceló, Damià

    2011-08-01

    Perfluorinated compounds (PFCs) are resistant to breakdown and are turning up in unexpected places around the world, becoming emerging food contaminants. Although these chemicals have been used in countless products since the 1950s, they have been subject to little control until now. There is still an insufficient knowledge of their sources, occurrence, and hazards for food safety decision making. This article provides a comprehensive review of the food contamination levels and dietary intake risks posed by PFCs, as well as the specific methods developed for their determination. It is based on the evaluation of the published literature between 2004 and the beginning of 2010, with special emphasis on those reports of the last two years and in the examination of the growing body of studies on the exposure assessment and food occurrence of PFCs. The current state-of-the art and future perspectives in extraction, clean-up, detection, identification, confirmation, and quantification highlighting the advantages and limitations of each technique have been summarized. How much is known about the sources and pathways of food web and human exposure, which is needed to control and manage the release of these emerging toxic contaminants, has also been explained.

  14. Groundwater pollution by perfluorinated surfactants in Tokyo.

    PubMed

    Murakami, Michio; Kuroda, Keisuke; Sato, Nobuyuki; Fukushi, Tetsuo; Takizawa, Satoshi; Takada, Hideshige

    2009-05-15

    Perfluorinated surfactants (PFSs) in groundwater were analyzed to reveal their distribution and sources. Sixteen groundwater and spring samples were collected from the Tokyo metropolitan area, and nine PFSs, including perfluorooctane-sulfonate (PFOS) and perfluorooctanoate (PFOA), were analyzed by liquid chromatography-tandem mass spectrometry. A column test using artificial street runoff was also performed to study their behavior. PFSs were detected in all groundwater samples, some at concentrations comparable to those in wastewater and street runoff, suggesting widespread contamination of groundwater by PFSs. In particular, PFOS -was more abundant in groundwater than in rivers, wastewater, and street runoff. This was attributed to its production from the degradation of its precursors, as supported by the column test. The occurrence of short-chain perfluorocarboxylates (PFCAs) in groundwater was also consistent with the results of the column test, showing that limited amounts of short-chain PFCAs were removed by soil, as the efficiency of removal increased with the chain length. We evaluated the contributions of PFCAs from wastewater and surface runoff to groundwater by using two indicators, the long/(short + long) ratio and the even(even + odd) ratio. Both ratios showed good agreement in their calculated contributions in heavily contaminated groundwater where breakthroughs likely occurred. Wastewater and surface runoff contributed to 54-86% and 16-46% of PFCAs, respectively, in groundwater.

  15. Serum concentrations of perfluorinated compounds (PFC) ...

    EPA Pesticide Factsheets

    Perfluorinated compounds (PFCs) have been widely used in industrial applications and consumer products. Their persistent nature and potential health impacts are of concern. Given the high cost of collecting serum samples, this study is to understand whether we can quantify PFC serum concentrations using factors extracted from questionnaire responses and indirect measurements, and whether a single serum measurement can be used to classify an individual′s exposure over a one-year period. The study population included three demographic groups: young children (2–8 years old) (N=67), parents of young children (55 years old) (N=59). PFC serum concentrations, house dust concentrations, and questionnaires were collected. The geometric mean of perfluorooctane sulfonic acid (PFOS) was highest for the older adults. In contrast, the geometric mean of perfluorooctanoic acid (PFOA) was highest for children. Serum concentrations of the parent and the child from the same family were moderately correlated (Spearman correlation (r)=0.26–0.79, p<0.05), indicating common sources within a family. For adults, age, having occupational exposure or having used fire extinguisher, frequencies of consuming butter/margarine, pork, canned meat entrées, tuna and white fish, freshwater fish, and whether they ate microwave popcorn were significantly positively associated with serum concentrations of individual PFCs. For children, residential dust

  16. Electrochemical oxidation of perfluorinated compounds in water.

    PubMed

    Niu, Junfeng; Li, Yang; Shang, Enxiang; Xu, Zesheng; Liu, Jinzi

    2016-03-01

    Perfluorinated compounds (PFCs) are persistent and refractory organic pollutants that have been detected in various environmental matrices and municipal wastewater. Electrochemical oxidation (EO) is a promising remediation technique for wastewater contaminated with PFCs. A number of recent studies have demonstrated that the "non-active" anodes, including boron-doped diamond, tin oxide, and lead dioxide, are effective in PFCs elimination in wastewater due to their high oxygen evolution potential. Many researchers have conducted experiments to investigate the optimal conditions (i.e., potential, current density, pH value, plate distance, initial PFCs concentration, electrolyte, and other factors) for PFCs elimination to obtain the maximal elimination efficiency and current efficiency. The EO mechanism and pathways of PFCs have been clearly elucidated, which undergo electron transfer, Kolbe decarboxylation or desulfonation, hydrolysis, and radical reaction. In addition, the safety evaluation and energy consumption evaluation of the EO technology have also been summarized to decrease toxic ion release from electrode and reduce the cost of this technique. Although the ultrasonication and hydrothermal techniques combined with the EO process can improve the removal efficiency and current efficiency significantly, these coupled techniques have not been commercialized and applied in industrial wastewater treatment. Finally, key challenges facing EO technology are listed and the directions for further research are pointed out (such as combination with other techniques, treatment for natural waters contaminated by low levels of PFCs, and reactor design).

  17. PERFLUORINATED COMPOUNDS IN ARCHIVED HOUSE-DUST SAMPLES

    EPA Science Inventory

    Archived house-dust samples were analyzed for 13 perfluorinated compounds (PFCs). Results show that PFCs are found in house-dust samples, and the data are log-normally distributed. PFOS/PFOA were present in 94.6% and 96.4% of the samples respectively. Concentrations ranged fro...

  18. 21 CFR 173.21 - Perfluorinated ion exchange membranes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Perfluorinated ion exchange membranes. 173.21... ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in the treatment of bulk quantities of liquid food under...

  19. 21 CFR 173.21 - Perfluorinated ion exchange membranes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Perfluorinated ion exchange membranes. 173.21... ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in the treatment of bulk quantities of liquid food under...

  20. 21 CFR 173.21 - Perfluorinated ion exchange membranes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Perfluorinated ion exchange membranes. 173.21... ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in the treatment of bulk quantities of liquid food under...

  1. 21 CFR 173.21 - Perfluorinated ion exchange membranes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Perfluorinated ion exchange membranes. 173.21... ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in the treatment of bulk quantities of liquid food under...

  2. Self-healing fuse development

    NASA Technical Reports Server (NTRS)

    Jones, N. D.; Kinsinger, R. E.; Harris, L. P.

    1973-01-01

    The mercury-filled self-healing fuses developed for this program afford very good protection from circuit faults with rapid reclosure. Fuse performance and design parameters have been characterized. Life tests indicate a capability of 500 fuse operations. Fuse ratings are 150 v at 5, 15, 25 and 50 circuit A. A series of sample fuses using alumina and beryllia insulation have been furnished to NASA for circuit evaluation.

  3. OLED panel with fuses

    SciTech Connect

    Levermore, Levermore; Pang, Huiqing; Rajan, Kamala

    2014-09-16

    Embodiments may provide a first device that may comprise a substrate, a plurality of conductive bus lines disposed over the substrate, and a plurality of OLED circuit elements disposed on the substrate, where each of the OLED circuit elements comprises one and only one pixel electrically connected in series with a fuse. Each pixel may further comprise a first electrode, a second electrode, and an organic electroluminescent (EL) material disposed between the first and the second electrodes. The fuse of each of the plurality of OLED circuit elements may electrically connect each of the OLED circuit elements to at least one of the plurality of bus lines. Each of the plurality of bus lines may be electrically connected to a plurality of OLED circuit elements that are commonly addressable and at least two of the bus lines may be separately addressable.

  4. Perfluorinated plastic optical fiber tapers for evanescent wave sensing.

    PubMed

    Gravina, Roberto; Testa, Genni; Bernini, Romeo

    2009-01-01

    In this work we describe the fabrication and the characterization of perfluorinated plastic-cladded optical fiber tapers. The heat-and-pull procedure has been used to fabricate symmetric tapers. Devices with different taper ratio have been produced and the repeatability of the process has been verified. The very low refractive indexes of the core-cladding perfluorinated polymers (n = 1.35-1.34) permit a strong enhancement of the evanescent wave power fraction in aqueous environments (n = 1.33), making them very attractive for evanescent wave sensing. The tapers have been characterized carrying out evanescent field absorbance measurements with different concentrations of methylene blue in water and fluorescence collection measurements in an aqueous solution containing Cy5 dye. A good sensitivity, tightly related to the low refractive index of the core-cladding materials and the geometrical profile, has been shown.

  5. Concentrations and trends of Perfluorinated chemicals in potential indoor sources from 2007 through 2011 in the US

    EPA Science Inventory

    Certain perfluorinated chemicals in consumer products have been associated with developmental toxicity and other adverse health effects. Temporal trends in the concentrations of selected perfluorinated chemicals (PFCs), including perfluorooctanoic acid (PFOA) and other perfluoroc...

  6. Removal of Perfluorinated Grease Components from NTO Oxidizer

    NASA Technical Reports Server (NTRS)

    McClure, Mark B.; Greene, Ben; Johnson, Harry T.

    2004-01-01

    Perfluorinated greases are typically used as a thread lubricant in the assembly of non-welded nitrogen tetroxide (NTO) oxidizer systems. These greases, typically a perfluoroalkylether, with suspended polytetrafluoroethylene (PTFE) micro-powder, have attractive lubricating properties toward threaded components and are relatively chemically inert toward NTO oxidizers. A major drawback, however, is that perfluoroalkylether greases are soluble or dispersible in NTO oxidizers and can contaminate the propellant. The result is propellant that fails the non-volatile residue (NVR) specification analyses and that may have negative effects on test hardware performance and lifetime. Consequently, removal of the grease contaminants from NTO may be highly desirable. Methods for the removal of perfluorinated grease components from NTO oxidizers including distillation, adsorption, filtration, and adjustment of temperature are investigated and reported in this work. Solubility or dispersibility data for the perfluoroalkylether oil (Krytox(tm)143 AC) component of a perfluorinated grease (Krytox 240 AC) and for Krytox 240 AC in NTO were determined and are reported.

  7. Bioaccumulation of perfluorinated alkyl acids: observations and models.

    PubMed

    Ng, Carla A; Hungerbühler, Konrad

    2014-05-06

    In this review, we consider the two prevailing hypotheses for the mechanisms that control the bioaccumulation of perfluorinated alkyl acids (PFAAs). The first assumes that partitioning to membrane phospholipids, which have a higher affinity for charged species than neutral storage lipids, can explain the high bioaccumulation potential of these compounds. The second assumes that interactions with proteins--including serum albumin, liver fatty acid binding proteins (L-FABP), and organic anion transporters--determine the distribution, accumulation and half-lives of PFAAs. We consider three unique phenomena to evaluate the two models: (1) observed patterns of tissue distribution in the laboratory and field, (2) the relationship between perfluorinated chain length and bioaccumulation, and (3) species- and gender-specific variation in elimination half-lives. Through investigation of these three characteristics of PFAA bioaccumulation, we show the strengths and weaknesses of the two modeling approaches. We conclude that the models need not be mutually exclusive, but that protein interactions are needed to explain some important features of PFAA bioaccumulation. Although open questions remain, further research should include perfluorinated alkyl substances (PFASs) beyond the long-chain PFAAs, as these substances are being phased out and replaced by a wide variety of PFASs with largely unknown properties and bioaccumulation behavior.

  8. Method for fusing bone

    DOEpatents

    Mourant, Judith R.; Anderson, Gerhard D.; Bigio, Irving J.; Johnson, Tamara M.

    1996-01-01

    Method for fusing bone. The present invention is a method for joining hard tissue which includes chemically removing the mineral matrix from a thin layer of the surfaces to be joined, placing the two bones together, and heating the joint using electromagnetic radiation. The goal of the method is not to produce a full-strength weld of, for example, a cortical bone of the tibia, but rather to produce a weld of sufficient strength to hold the bone halves in registration while either external fixative devices are applied to stabilize the bone segments, or normal healing processes restore full strength to the tibia.

  9. Computational investigation of the effects of perfluorination on the charge-transport properties of polyaromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Cardia, R.; Malloci, G.; Bosin, A.; Serra, G.; Cappellini, G.

    2016-10-01

    We present a systematic computational study of the effects of perfluorination on the charge-transport properties of three homologous classes of polyaromatic hydrocarbons of interest for molecular electronics: acenes, pyrenes, and circumacenes. By means of Density Functional Theory calculations we first obtained the key molecular properties for transport of both holes and electrons. We then used these parameters in the framework of Marcus theory to compare charge-transfer rates in the high temperatures regime for both unsubstituted and perfluorinated molecules. We additionally estimated the relative charge-mobility of each unsubstituted (perfluorinated) molecule with respect to unsubstituted (perfluorinated) pentacene. We found in all cases that perfluorination reduces the charge-transfer rate in absolute terms. This is largely due to the higher values of the molecular reorganization energies predicted for perfluorinated compounds. Interestingly, however, the charge-transfer rates for both holes and electrons of perfluorinated species are remarkably similar, especially for the larger species. In addition, in the case of the larger circumacenes the charge-mobility values relative to pentacene values are found to increase upon perfluorination.

  10. Fused Lasso Additive Model

    PubMed Central

    Petersen, Ashley; Witten, Daniela; Simon, Noah

    2016-01-01

    We consider the problem of predicting an outcome variable using p covariates that are measured on n independent observations, in a setting in which additive, flexible, and interpretable fits are desired. We propose the fused lasso additive model (FLAM), in which each additive function is estimated to be piecewise constant with a small number of adaptively-chosen knots. FLAM is the solution to a convex optimization problem, for which a simple algorithm with guaranteed convergence to a global optimum is provided. FLAM is shown to be consistent in high dimensions, and an unbiased estimator of its degrees of freedom is proposed. We evaluate the performance of FLAM in a simulation study and on two data sets. Supplemental materials are available online, and the R package flam is available on CRAN. PMID:28239246

  11. Coupling losses in perfluorinated multi-core polymer optical fibers.

    PubMed

    Durana, Gaizka; Aldabaldetreku, Gotzon; Zubia, Joseba; Arrue, Jon; Tanaka, Chikafumi

    2008-05-26

    The aim of the present paper is to provide a comprehensive analysis of coupling losses in perfluorinated (PF) multi-core polymer optical fibers (MC-POFs), which consist of groups of 127 graded-index cores. In our analysis we take into account geometrical, longitudinal, transverse, and angular misalignments. We perform several experimental measurements and computer simulations in order to calculate the coupling losses for a PF MC-POF prototype. Based on these results, we propose several hints of practical interest to the manufacturer which would allow an appropriate connector design in order to handle conveniently the coupling losses incurred when connectorizing two PF MC-POFs.

  12. Multi-Platform Metabolomic Analyses of Rat Urine Following Exposure to Perfluorinated Chemicals (PFCs)

    EPA Science Inventory

    Perfluorinated chemicals (PFCs), namely perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), represent an emerging class of persistent and bioaccumulative compounds. Global occurrence of these fluorochemicals, coupled with probable human exposure, has prompted inv...

  13. Effects of Perfluorinated Phosphonic Acid Exposure during pregnancy in the mouse

    EPA Science Inventory

    Perfluorinated phosphonic acids (PFPAs) are a member of the perfluoroalkyl acid (PFAA) family, and are structurally similar to the perfluoroalkyl sulfonates and perfluoroalkyl carboxylates. These chemicals have recently been detected in the environment, particularly in surface wa...

  14. DETERMINATION OF PERFLUORINATED CHEMICALS (PFCS) IN SOILS, SEDIMENT AND OTHER MATRICES

    EPA Science Inventory

    Soils that receive land application of treated wastewater from carpet manufacturing plants were sampled for perfluorooctanoic acid (PFOA) and other perfluorinated chemicals (PFCs) that are potential degradation products of fluorotelomer-based polymers (FBPs). Soils from other pot...

  15. Determination of Ten Perfluorinated Compounds in Bluegill Sunfish (Lepomis macrochirus) Fillets

    EPA Science Inventory

    Limited information is known about the environmental distributions of the perfluorinated compounds (PFCs) such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), in part due to a lack of well characterized analytical methods that can be used to accurately mea...

  16. Factors Affecting the Distribution of Perfluorinated Compounds in Sediments from Lake Shihwa, Korea

    EPA Science Inventory

    Perfluorinated compounds (PFCs) are ubiquitously distributed in various environmental media including water, soil, sediment, and biota. PFCs have also been shown to biomagnify in both aquatic and terrestrial environments. Lake Shihwa is an artificial saltwater lake, located on ...

  17. AN INTERLABORATORY STUDY OF PERFLUORINATED ALKYL COMPOUND LEVELS IN HUMAN PLASMA

    EPA Science Inventory

    The present study was designed to investigate intra- and interlaboratory variability in results from six laboratories experienced in the analysis of perfluorinated alkyl compounds in blood matrices and that use stringent procedures to control and assure accuracy and precision. Ea...

  18. Preliminary assessment of developmental toxicity of Perfluorinated Phosphonic Acid in mice

    EPA Science Inventory

    Perfluorinated phosphonic acids (PFPAs) are a third member of the perfluoroalkyl acid (PFAA) family, and are structurally similar to the perfluoroalkyl sulfonates and perfluoroalkyl carboxylates. These emerging chemicals have recently been detected in the environment, particularl...

  19. Perfluorinated Compounds in Fish from U.S. Urban Rivers and the Great Lakes

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have recently received scientific and regulatory attention due to their broad environmental distribution, persistence, bioaccumulative potential, and toxicity. Some studies suggest that the consumption of fish from contaminated waters may be a maj...

  20. Watershed-based riverine discharge loads and emission factor of perfluorinated surfactants in Korean peninsula.

    PubMed

    Kim, Seung-Kyu

    2012-11-01

    Long-range transport of and exposure to perfluorinated substances (PFSs) strongly depend on their emission mode. In the present study, watershed-based riverine discharge loads and emission factors are estimated for perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorohexylsulfonate (PFHxS), and perfluorooctylsulfonate (PFOS) by using spatially distributed data of chemical concentrations together with water flows and a geographic information system (GIS). Average per capita emissions (emission factor, μg capita(-1) d(-1)) are 75 for PFOA, 36 for PFNA, 17 for PFHxS, and 43 for PFOS, which are several times lower than the estimates for Japan and the European continent. A relatively uniform distribution is observed for PFHxS and PFOS emission factors, while elevated values of PFOA and PFNA predominate in one of eight river basins. This may indicate the leading contribution of diffusive sources (e.g. nonpoint source) for PFHxS and PFOS versus the presence of localized point sources for PFOA and PFNA. The lower-upper bound of total riverine loads discharged annually from the Korean peninsula are in the range of 0.53-1.3 tons for PFOA, 0.09-0.60 tons for PFNA, 0.07-0.29 tons for PFHxS, and 0.19-0.73 tons for PFOS, accounting for <1% of global annual emissions. Furthermore, these riverine discharge loads are significantly greater than the discharge loads from a wastewater treatment plant, indicating the necessity of further study of nonpoint sources.

  1. Perfluorinated contaminants in fur seal pups and penguin eggs from South Shetland, Antarctica.

    PubMed

    Schiavone, A; Corsolini, S; Kannan, K; Tao, L; Trivelpiece, W; Torres, D; Focardi, S

    2009-06-01

    Perfluorinated compounds (PFCs) have emerged as a new class of global environmental pollutants. In this study, the presence of perfluorochemicals (PFCs) in penguin eggs and Antarctic fur seals was reported for the first time. Tissue samples from Antarctic fur seal pups and penguin eggs were collected during the 2003/04 breeding season. Ten PFC contaminants were determined in seal and penguin samples. The PFC concentrations in seal liver were in the decreasing order, PFOS>PFNA>PFHpA>PFUnDA while in Adélie penguin eggs were PFHpA>PFUnDA>PFDA>PFDoDA, and in Gentoo penguin eggs were PFUnDA>PFOS>PFDoDA>PFHpA. The PFC concentrations differed significantly between seals and penguins (p<0.005) and a species-specific difference was found between the two species of penguins (p<0.005). In our study we found a mean concentration of PFOS in seal muscle and liver samples of 1.3 ng/g and 9.4 ng/g wet wt, respectively, and a mean concentration in Gentoo and Adélie penguin eggs of 0.3 ng/g and 0.38 ng/g wet wt, respectively. PFCs detected in penguin eggs and seal pups suggested oviparous and viviparous transfer of PFOS to eggs and off-springs.

  2. Perfluorinated polymer optical fiber for gamma radiation monitoring

    NASA Astrophysics Data System (ADS)

    Stajanca, P.; Mihai, L.; Sporea, D.; Negut, D.; Krebber, K.

    2016-05-01

    The sensitivity of low-loss perfluorinated polymer optical fiber (PF-POF) to gamma radiation is investigated for on-line radiation monitoring purposes. The radiation-induced attenuation (RIA) of a commercial PF-POF based on Cytop material is measured in the visible spectral region. The fiber RIA shows strong wavelength dependence with rapid increase towards the blue side of the spectrum. The wide range of radiation sensitivities is available via careful selection of appropriate monitoring wavelength. The accessible sensitivities span from 1.6 +/- 0.2 dBm-1/kGy measured at 750 nm to 18.3 +/- 0.7 dBm-1/kGy measured at 420 nm. The fairly high radiation sensitivity as well as its wide tunability makes the fiber a promising candidate for a broad range of applications.

  3. (PRESENTED AT TSUKUBA, JAPAN) PERSISTENT PERFLUORINATED ORGANIC COMPOUNDS METHOD DEVELOPMENT RESEARCH AT THE U.S. ENVIRONMENTAL PROTECTION AGENCY

    EPA Science Inventory

    PowerPoint presentation summarizing method development research involving the persistent perfluorinated organic compounds. Review of data indicating widespread distribution of these materials and the potential for toxicity.

  4. A new and efficient procedure for the synthesis of hexahydropyrimidine-fused 1,4-naphthoquinones

    PubMed Central

    Reis, Marcelo Isidoro P; Campos, Vinícius R; Resende, Jackson A L C; Silva, Fernando C

    2015-01-01

    Summary A new and efficient method for the synthesis of hexahydropyrimidine-fused 1,4-naphthoquinones in one step with high yields from the reaction of lawsone with 1,3,5-triazinanes was developed. PMID:26425181

  5. Heteroleptic Tetrapyrrole-Fused Dimeric and Trimeric Skeletons with Unusual Non-Frustrated Fluorescence.

    PubMed

    Zhang, Yuehong; Oh, Juwon; Wang, Kang; Chen, Chao; Cao, Wei; Park, Kyu Hyung; Kim, Dongho; Jiang, Jianzhuang

    2016-03-18

    Phthalocyanine (Pc) and porphyrin (Por) chromophores have been fused through the benzo[α]pyrazine moiety, resulting in unprecedented heteroleptic tetrapyrrole-fused dimers and trimers. The heteroleptic tetrapyrrole nature has been clearly revealed based on single-crystal X-ray diffraction analysis of the zinc dimer. Electrochemical analysis, theoretical calculations, and time-resolved spectroscopic results disclose that the two/three-tetrapyrrole-fused skeletons behave as one totally π-conjugated system as a result of the strong conjugative interaction between/among the tetrapyrrole chromophores. In particular, the effectively extended π-electron system through the fused-bridge induced strong electronic communication between the Pc and Por moieties and large transition dipole moments in the Pc-Por-fused systems, providing high fluorescence quantum yields (>0.13) and relatively long excited state lifetimes (>1.3 ns) in comparison with their homo-tetrapyrrole-fused analogues.

  6. 1,3-Dichlorobenzene

    Integrated Risk Information System (IRIS)

    1,3 - Dichlorobenzene ; CASRN 541 - 73 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinog

  7. 1,3-Dichloropropene

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 00 / 001 TOXICOLOGICAL REVIEW OF 1,3 - DICHLOROPROPENE ( CAS No . 542 - 75 - 6 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) May 2000 U.S . Environmental Protection Agency Washington , DC DISCLAIMER This document has been reviewed in accordanc

  8. 1,3-Butadiene

    Integrated Risk Information System (IRIS)

    1,3 - Butadiene ; CASRN 106 - 99 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic E

  9. Mass spectra of tetrahydroisoquinoline-fused 1,3,2-O,N,P- and 1,2,3-O,S,N-heterocycles: influence of ring size and fusion, of present heteroatoms, substituent effects and of the stereochemistry on fragmentation.

    PubMed

    Starke, Ines; Schuster, Ildikó; Fülöp, Ferenc; Kleinpeter, Erich

    2008-05-01

    The electron ionization (EI) mass spectra of a variety of stereoisomeric tricyclic 1,3,2-oxazaphosphino[4,3-a]isoquinolines (1-4), 1,2,3-oxathiazino[4,3-a]isoquinoline-4-oxides (5-7) and the -4,4-dioxides (8-10) of oxazaphospholo- and oxathiazolo[4,3-a]- (11, 12, 15 and 16) and -[3,4-b]isoquinolines (13, 14 and 17) were recorded. Ring size and fusion, the different heteroatoms (P and S) and substituents on the ring systems strongly influence the mass spectra. In addition, mass spectra of the stereoisomers of compounds 1, 2 and 13, 14 revealed stereochemically relevant differences which are not observed for the other pairs of isomers.

  10. Unusual dynamic dewetting behavior of smooth perfluorinated hybrid films: potential advantages over conventional textured and liquid-infused perfluorinated surfaces.

    PubMed

    Urata, Chihiro; Masheder, Benjamin; Cheng, Dalton F; Hozumi, Atsushi

    2013-10-08

    From a viewpoint of reducing the burden on the environment and human health, an alternative method for preparing liquid-repellent surfaces without relying on the long perfluorocarbons (C((X-1)/2)F(X), X ≥ 17) has been strongly demanded lately. In this study, we have successfully demonstrated that dynamic dewettability toward various probe liquids (polar and nonpolar liquids with high or low surface tension) can be tuned by not only controlling surface chemistries (surface energies) but also the physical (solid-like or liquid-like) nature of the surface. We prepared smooth and transparent organic-inorganic hybrid films exhibiting unusual dynamic dewetting behavior toward various probe liquids using a simple sol-gel reaction based on the co-hydrolysis and co-condensation of a mixture including a range of perfluoroalkylsilanes (FASX, C((X-1)/2)F(X)CH2CH2Si(OR)3, where X = 3, 9, 13, and 17) and tetramethoxysilane (Si(OCH3)4, TMOS). Dynamic contact angle (CA) and substrate tilt angle (TA) measurements confirmed that our FASX-hybrid films exhibited excellent dynamic dewetting properties and were mostly independent of the length of perfluoroalkyl (Rf) groups. For example, 10 μL droplets of ultralow surface tension liquids (e.g., diethyl ether (γ = 16.26 dyn/cm) and n-pentane (γ = 15.51 dyn/cm)) could move easily on our FAS9-, FAS13-, and FAS17-hybrid film surfaces at low substrate TAs (<4°) without pinning. This is comparable or superior to the best perfluorinated textured and flat surfaces reported so far. This exceptional dynamic dewetting behavior appeared only when TMOS molecules were added to the precursor solutions; we assume this is due to co-condensed TMOS-derived silica species working as spacers between the neighboring Rf chains, enabling them to rotate freely and in doing so provide a surface with liquid-like properties. This led to the distinguished dynamic dewettability of our hybrid films, regardless of the small static CAs. Our FASX-hybrid films also

  11. Biomonitoring of perfluorinated compounds in a drop of blood.

    PubMed

    Mao, Pan; Wang, Daojing

    2015-06-02

    Biomonitoring of pollutants and their metabolites and derivatives using biofluids provides new opportunities for spatiotemporal assessment of human risks to environmental exposures. Perfluorinated compounds (PFCs) have been used widely in industry and pose significant environmental concerns due to their stability and bioaccumulation in humans and animals. However, current methods for extraction and measurement of PFCs require relatively large volumes (over one hundred microliters) of blood samples, and therefore, are not suitable for frequent blood sampling and longitudinal biomonitoring of PFCs. We have developed a new microassay, enabled by our silicon microfluidic chip platform, for analyzing PFCs in small volumes (less than five microliters) of blood. Our assay integrates on-chip solid-phase extraction (SPE) with online nanoflow liquid chromatography-electrospray ionization-mass spectrometry (nanoLC-ESI-MS) detection. We demonstrated high sample recovery, excellent interday and intraday accuracy and precision, and a limit of detection down to 50 femtogram of PFCs, in one microliter of human plasma. We validated our assay performance using pooled human plasma and NIST SRM 1950 samples. Our microfluidic chip-based assay may enable frequent longitudinal biomonitoring of PFCs and other environmental toxins using a finger prick of blood, thereby providing new insights into their bioaccumulation, bioavailability, and toxicity.

  12. Gastrointestinal Elimination of Perfluorinated Compounds Using Cholestyramine and Chlorella pyrenoidosa

    PubMed Central

    Genuis, Stephen J.; Curtis, Luke; Birkholz, Detlef

    2013-01-01

    Background. While perfluorinated compounds (PFCs) are a family of commonly used synthetic compounds with many applications, some PFCs remain persistent within the human body due, in part, to enterohepatic recirculation and renal tubular reabsorption. With increasing recognition of potential harm to human health associated with PFC bioaccumulation, interventions to facilitate elimination of these toxicants are welcome in order to potentially preclude or overcome illness. Minimal research has been undertaken thus far on methods to accelerate human clearance of PFCs. Methods. To test for possible oral treatments to hasten PFC elimination, a group of individuals with elevated PFC levels was treated with cholestyramine (CSM) and, after a break, was subsequently treated with Chlorella pyrenoidosa (CP). Stool samples were collected from all participants (i) prior to any treatment, (ii) during treatment with CSM, and (iii) during treatment with CP. Results. With CSM treatment, significant levels of three distinct PFCs were found in all stools, while levels were mostly undetectable prior to treatment. Following treatment with oral CP, undetectable or very low levels of all PFCs were noted in each sample tested. Conclusion. CSM appears to facilitate elimination of some common PFCs and may have some role in the clinical management of patients with accrued PFCs. PMID:24106616

  13. [Residue Characteristics of Perfluorinated Compounds in the Atmosphere of Shenzhen].

    PubMed

    He, Peng-fei; Zhang, Hong; Li, Jing; He, Long; Luo, Ji; Liu, Guo-qing; Shen, Jin-can; Yang, Bo; Cui, Xiao-yu

    2016-04-15

    In order to explore the residual characteristics of perfluorinated compounds (PFCs) in the atmosphere of Shenzhen, passive air samplers consisting of polyurethane foam (PUF) disks impregnated with XAD-4 power were deployed at 12 sites in Shenzhen from November 2014 to February 2015. Seven volatile and fifteen ionic PFCs were analyzed. The results indicated that ΣPFCs concentration ranged from 23.7 pg x m(-3) to 157 pg x m(-3) (mean: 79.0 pg x m(-3)), dominated by volatile PFCs, with 8:2 FTOITI, 6:2 FTOH, PFPeA, PFOA being the dominant compounds. The spatial distribution of volatile and ionic PFCs concentrations was the same, displaying the characteristic of "the northwest being higher than the southeast ". Furthermore, the concentrations of 6:2 FTOHs, 8:2 FTOHs, PFPeA, PFHxA and PFOA had positive correlations with PM2.5 and PM10 (P < 0.05, P < 0.01) and were more positively correlated with the levels of PM10 than those of PM2.5.

  14. Biomonitoring of Perfluorinated Compounds in a Drop of Blood

    PubMed Central

    2015-01-01

    Biomonitoring of pollutants and their metabolites and derivatives using biofluids provides new opportunities for spatiotemporal assessment of human risks to environmental exposures. Perfluorinated compounds (PFCs) have been used widely in industry and pose significant environmental concerns due to their stability and bioaccumulation in humans and animals. However, current methods for extraction and measurement of PFCs require relatively large volumes (over one hundred microliters) of blood samples, and therefore, are not suitable for frequent blood sampling and longitudinal biomonitoring of PFCs. We have developed a new microassay, enabled by our silicon microfluidic chip platform, for analyzing PFCs in small volumes (less than five microliters) of blood. Our assay integrates on-chip solid-phase extraction (SPE) with online nanoflow liquid chromatography-electrospray ionization-mass spectrometry (nanoLC-ESI-MS) detection. We demonstrated high sample recovery, excellent interday and intraday accuracy and precision, and a limit of detection down to 50 femtogram of PFCs, in one microliter of human plasma. We validated our assay performance using pooled human plasma and NIST SRM 1950 samples. Our microfluidic chip-based assay may enable frequent longitudinal biomonitoring of PFCs and other environmental toxins using a finger prick of blood, thereby providing new insights into their bioaccumulation, bioavailability, and toxicity. PMID:25997583

  15. Effects of perfluorinated amphiphiles on backward swimming in Paramecium caudatum

    SciTech Connect

    Matsubara, Eriko; Harada, Kouji; Inoue, Kayoko; Koizumi, Akio . E-mail: koizumi@pbh.med.kyoto-u.ac.jp

    2006-01-13

    PFOS and PFOA are ubiquitous contaminants in the environment. We investigated the effects of fluorochemicals on calcium currents in Paramecium caudatum using its behavioral changes. Negatively charged amphiphiles prolonged backward swimming (BWS) of Paramecium. PFOS significantly prolonged BWS, while PFOA was less potent (EC{sub 5}: 29.8 {+-} 4.1 and 424.1 {+-} 124.0 {mu}M, respectively). The BWS prolongation was blocked by cadmium, indicating that the cellular calcium conductance had been modified. The positively charged amphiphile FOSAPrTMA shortened BWS (EC{sub 5}: 19.1 {+-} 17.3). Nonionic amphiphiles did not affect BWS. The longer-chain perfluorinated carboxylates PFNA and PFDA were more potent than PFOA (EC{sub 5}: 98.7 {+-} 20.1 and 60.4 {+-} 10.1 {mu}M, respectively). However, 1,8-perfluorooctanedioic acid and 1,10-perfluorodecanedioic acid did not prolong BWS. The critical micelle concentration (CMC) and BWS prolongation for negatively charged amphiphiles showed a clear correlation (r {sup 2} = 0.8008, p < 0.001). In summary, several perfluorochemicals and PFOS and PFOA had similar effects in Paramecium, while chain length, CMC, and electric charge were major determinants of BWS duration.

  16. Effects of gamma radiation on perfluorinated polymer optical fibers

    NASA Astrophysics Data System (ADS)

    Stajanca, Pavol; Mihai, Laura; Sporea, Dan; Neguţ, Daniel; Sturm, Heinz; Schukar, Marcus; Krebber, Katerina

    2016-08-01

    The paper presents the first complex study of gamma radiation effects on a low-loss perfluorinated polymer optical fiber (PF-POF) based on Cytop® polymer. Influence of gamma radiation on fiber's optical, mechanical and climatic performance is investigated. The radiation-induced attenuation (RIA) in the visible and near-infrared region (0.4 μm-1.7 μm) is measured and its origins are discussed. Besides attenuation increase, radiation is also shown to decrease the thermal degradation stability of the fiber and to increase its susceptibility to water. With regard to complex fiber transmission performance upon irradiation, the optimal operation wavelength region of PF-POF-based systems intended for use in radiation environments is determined to be around 1.1 μm. On the other hand, the investigated fiber holds potential for low-cost RIA-based optical fiber dosimetry applications with sensitivity as high as 260 dBm-1/kGy in the visible region.

  17. Online monitoring of gamma irradiated perfluorinated polymer optical fiber

    NASA Astrophysics Data System (ADS)

    Sporea, Dan; Mihai, Laura; Neguţ, Daniel; Stajanca, Pavol; Krebber, Katerina

    2016-04-01

    In this paper, we present the first results regarding the on-line monitoring of gamma-ray exposure effects on a commercial multi-mode perfluorinated polymer optical fiber (PF-POF), type GigaPOF-50SR from Chromis Fiberoptics. Our focus was to evaluate on-line the radiation induced attenuation (RIA) over a wide spectral range (320 nm - 1700 nm), in order to assess the fiber's radiation hardness and its possible use in radiation detection. An Ocean Optics QE65000 high sensitivity spectrometer and a StellarNet near-IR spectrometer were used to cover the spectral ranges 200 nm - 1μm and 900 nm - 1.6 μm, respectively. Electron paramagnetic resonance was used to monitor the recovery of the irradiation induced centers at room temperature. The study indicated that the optical fiber can be used as radiation monitor at low dose rates by measuring the attenuation in the UV, while higher dose rates irradiation can be observed by RIA monitoring at specific wavelengths in the visible spectral range.

  18. Electrolytic production of neodymium without perfluorinated carbon compounds on the offgases

    DOEpatents

    Keller, Rudolf; Larimer, Kirk T.

    1998-01-01

    A method of producing neodymium in an electrolytic cell without formation of perfluorinated carbon gases (PFCs), the method comprising the steps of providing an electrolyte in the electrolytic cell and providing an anode in an anode region of the electrolyte and providing a cathode in a cathode region of the electrolytic cell. Dissolving an oxygen-containing neodymium compound in the electrolyte in the anode region and maintaining a more intense electrolyte circulation in the anode region than in the cathode region. Passing an electrolytic current between said anode and said cathode and depositing neodymium metal at the cathode, preventing the formation of perfluorinated carbon gases by limiting anode over voltage.

  19. FUSE satellite electrical power subsystem

    SciTech Connect

    Roufberg, L.; Noah, K.

    1998-07-01

    The Far Ultraviolet Spectroscopic Explorer (FUSE) satellite will be placed into a low earth orbit to investigate astrophysical processes related to the formation and development of the early universe. The FUSE satellite is considered a pathfinder for NASA's Mid-Class Explorers (MIDEX). To reduce mission cost and development time while delivering quality science, NASA has enforced strict cost caps with a clear definition of high-level science objectives. As a result, a significant design driver for the electrical power subsystem (EPS) was to minimize cost. The FUSE EPS is a direct energy transfer, unregulated bus architecture, with batteries directly on the bus and solar array power limted by pulse-width-modulated shunt regulators. The power subsystem electronics (PSE) contains circuitry to control battery charging, provide power to the loads, and provide fault protection. The electronics is based on the PSE which Orbital (formerly, Fairchild Space) designed and built for NASA/GSFC's XTE spacecraft. However, the FUSE PSE design incorporates a number of unique features to meet the mission requirements. To minimize size of the solar panels due to stowed attachment constraints, GaAs/Ge solar cells were selected. This is the first time this type of large area, thinned solar cell with integral bypass diodes are being used for a NASA LEO mission. The solar panels support a satellite load power of 520W. Nickel Cadmium (NiCd) batteries are used which are identical to the RADARSAT-I design, except for different temperature sensors. This is the first mission for which Orbital is using SAFT NiCd batteries. The spacecraft bus, including the EPS, has successfully completed environmental testing and has been delivered for instrument integration. Tradeoffs involved in designing the EPS and selecting components based on the requirements are discussed. Analyses including solar array and battery sizing and energy balance are presented in addition to results from testing the flight

  20. 16 CFR 1507.3 - Fuses.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES § 1507.3 Fuses. (a) Fireworks devices that require a fuse shall: (1) Utilize only a fuse that has been... it will support either the weight of the fireworks device plus 8 ounces of dead weight or double...

  1. 16 CFR 1507.3 - Fuses.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES § 1507.3 Fuses. (a) Fireworks devices that require a fuse shall: (1) Utilize only a fuse that has been... it will support either the weight of the fireworks device plus 8 ounces of dead weight or double...

  2. 16 CFR 1507.3 - Fuses.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES § 1507.3 Fuses. (a) Fireworks devices that require a fuse shall: (1) Utilize only a fuse that has been... it will support either the weight of the fireworks device plus 8 ounces of dead weight or double...

  3. 16 CFR 1507.3 - Fuses.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS FIREWORKS DEVICES § 1507.3 Fuses. (a) Fireworks devices that require a fuse shall: (1) Utilize only a fuse that has been... it will support either the weight of the fireworks device plus 8 ounces of dead weight or double...

  4. 30 CFR 56.6502 - Safety fuse.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... purpose. Carbide lights, liquefied petroleum gas torches, and cigarette lighters shall not be used to light safety fuse. (h) At least two persons shall be present when lighting safety fuse, and no one shall light more than 15 individual fuses. If more than 15 holes per person are to be fired,...

  5. 30 CFR 57.6502 - Safety fuse.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... with devices designed for that purpose. Carbide lights, liquefied petroleum gas torches, and cigarette lighters shall not be used to light safety fuse. (h) At least two persons shall be present when lighting safety fuse, and no one shall light more than 15 individual fuses. If more than 15 holes per person...

  6. 30 CFR 28.2 - Approved fuses.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... MINING PRODUCTS FUSES FOR USE WITH DIRECT CURRENT IN PROVIDING SHORT-CIRCUIT PROTECTION FOR TRAILING CABLES IN COAL MINES General Provisions § 28.2 Approved fuses. (a) On and after the effective date of this part, fuses shall be considered to be approved for use with direct current in providing...

  7. Ferrocene-fused derivatives of acenes, tropones and thiepins

    NASA Astrophysics Data System (ADS)

    Maharjan, Bidhya Laxmi

    bottomcontact, bottom-gate (BCBG) device architecture and the resulting performance parameters are described herein. Similarly, we are also interested in potential applications of metallocene-fused tropones and derivatives as organic electronic materials. Condensation of 1,2- diformylferrocene with acetone or 1,3-diphenylacetone in the presence of KOH resulted in the ferrocene-fused tropone (eta5-2,4-cyclopentadien-1-yl)[(1,2,3,3a,8a-eta)-1,6-dihydro- 6-oxo-1-azulenyl]iron (1, R = H, E = O) and its 5,7-diphenyl derivative (1, R = Ph, E = O) as previously reported by Tirouflet. The use of piperidine as base resulted in Michael addition of piperidine to one of the carbon-carbon double bonds of the tropones. Lawesson's reagent converted the ferrocene-fused tropones to either a thiotropone (1, R = H, E = S) or a detached 5,7-diphenylazulenethiol (2). Reaction of the ferrocene-fused thiotropone with hydroxylamine gave the corresponding oxime (1, R = H, E = NOH). Products were characterized by using spectroscopic methods and X-ray crystallography. Their electronic properties were studied by using cyclic voltammetry and UV-visible spectroscopy. The third project involved the two-fold aldol condensation of 1,2- diformylferrocene with dimethylthioglycolate S-oxide in the presence of freshly distilled triethylamine, which gave mono- and di-dehydrated products. Deoxygenation of the ferrocene-fused thiepin S-oxide with 2-chloro-1,3,2-benzodioxaphosphole in the presence of pyridine resulted in the corresponding thiepin. The ester groups of the thiepin and thiepin S-oxide were hydrolyzed under basic conditions to give carboxylic acids, which were converted into acid chlorides using oxalyl chloride. Attempts to decarboxylate the thiepin and thiepin S-oxide diacids resulted in decomposition.

  8. Occurrence and sources of perfluorinated surfactants in rivers in Japan.

    PubMed

    Murakami, Michio; Imamura, Eiji; Shinohara, Hiroyuki; Kiri, Kentaro; Muramatsu, Yuki; Harada, Arata; Takada, Hideshige

    2008-09-01

    We analyzed perfluorinated surfactants (PFSs) in 20 river samples and 5 wastewater secondary effluent samples in Japan to reveal their occurrence and sources. Nine PFS species were determined: perfluorooctanesulfonate (PFOS), perfluorooctane sulfonamide (FOSA), perfluoroheptanoate (PFHpA), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), perfluoroundecanoate (PFUA), perfluorododecanoate (PFDDA), and perfluorotridecanoate (PFTDA). PFSs were detected in all rivers, revealing nationwide contamination of rivers. In particular, 11 out of 20 river samples exceeded New Jersey guidance for PFOA in drinking water (40 ng/L). PFOS, PFHpA, PFOA, and PFNA were major species in Japan. Concentrations of PFOS, PFHpA, and PFNA in rivers were strongly correlated with population density, suggesting that the chemicals were derived from urban activities. PFOA showed a significant but weak correlation. We used crotamiton, a marker of sewage effluent, for further source analysis. Concentrations of PFOS, PFHpA, and PFNAwere strongly correlated with those of crotamiton, and plots of secondary effluents fell near the regression lines of rivers, indicating that the PFOS, PFHpA, and PFNA in rivers were derived from sewage effluent. On the other hand, PFOA was found at remarkably high levels (54-192 ng/L) in seven river samples containing low levels of crotamiton, suggesting that it was derived from nonsewage point sources, as well as sewage effluent. The total fluxes of sewage-derived PFOS, PFHpA, PFOA, and PFNA from Japan were estimated to be 3.6, 2.6, 5.6, and 2.6 t/year, respectively. This is the first report to identify PFOA in several rivers, derived from nonsewage point sources, by using a marker of sewage effluent.

  9. Perfluorinated acids in Arctic snow: new evidence for atmospheric formation.

    PubMed

    Young, Cora J; Furdui, Vasile I; Franklin, James; Koerner, Roy M; Muir, Derek C G; Mabury, Scott A

    2007-05-15

    Perfluorinated acids (PFAs) are ubiquitously found in water and biota, including remote regions such as the High Arctic. Under environmental conditions, PFAs exist mainly as anions and are not expected to be subject to long-range atmospheric transport in the gas phase. Fluorinated telomer alcohols (FTOHs) are volatile and can be atmospherically oxidized to form perfluorocarboxylic acids. Analogously, fluorosulfamido alcohols can be oxidized to form perfluorooctane sulfonate (PFOS). High Arctic ice caps experience contamination solely from atmospheric sources. By examining concentrations of PFAs in ice cap samples, it is possible to determine atmospheric fluxes to the Arctic. Ice samples were collected from high Arctic ice caps in the spring of 2005 and 2006. Samples were concentrated using solid-phase extraction and analyzed by LC-MS-MS. PFAs were observed in all samples, dating from 1996 to 2005. Concentrations were in the low-mid pg L(-1) range and exhibited seasonality, with maximum concentrations in the spring-summer. The presence of perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUnA) on the ice cap was indicative of atmospheric oxidation as a source. Ratios of PFAs to sodium concentrations were highly variable, signifying PFA concentrations on the ice cap were unrelated to marine chemistry. Fluxes of the PFAs were estimated to the area north of 65 degrees N for the 2005 season, which ranged from 114 to 587 kg year(-1) for perfluorooctanoic acid (PFOA), 73 to 860 kg year(-1) for perfluorononanoic acid (PFNA), 16 to 84 kg year(-1) for PFDA, 26 to 62 kg year(-1) for PFUnA, and 18 to 48 kg year(-1) for PFOS. The PFOA and PFNA fluxes agreed with FTOH modeling estimations. A decrease in PFOS concentrations through time was observed, suggesting a fast response to changes in production. These data suggest that atmospheric oxidation of volatile precursors is a primary source of PFAs to the Arctic.

  10. Impact of perfluorination on the charge-transport parameters of oligoacene crystals.

    PubMed

    Delgado, M Carmen Ruiz; Pigg, Kathryn R; da Silva Filho, Demétrio A; Gruhn, Nadine E; Sakamoto, Youichi; Suzuki, Toshiyasu; Osuna, Reyes Malavé; Casado, Juan; Hernández, Víctor; Navarrete, Juan Teodomiro López; Martinelli, Nicolas G; Cornil, Jérôme; Sánchez-Carrera, Roel S; Coropceanu, Veaceslav; Brédas, Jean-Luc

    2009-02-04

    The charge-transport parameters of the perfluoropentacene and perfluorotetracene crystals are studied with a joint experimental and theoretical approach that combines gas-phase ultraviolet photoelectron spectroscopy and density functional theory. To gain a better understanding of the role of perfluorination, the results for perfluoropentacene and perfluorotetracene are compared to those for their parent oligoacenes, that is, pentacene and tetracene. Perfluorination is calculated to increase the ionization potentials and electron affinities by approximately 1 eV, which is expected to reduce significantly the injection barrier for electrons in organic electronics devices. Perfluorination also leads to significant changes in the crystalline packing, which greatly affects the electronic properties of the crystals and their charge-transport characteristics. The calculations predict large conduction and valence bandwidths and low hole and electron effective masses in the perfluoroacene crystals, with the largest mobilities expected along the pi-stacks. Perfluorination impacts as well both local and nonlocal vibrational couplings, whose strengths increase by a factor of about 2 with respect to the parent compounds.

  11. Perfluorinated nitrosopyrazolone-based erbium chelates: a new efficient solution processable NIR emitter.

    PubMed

    Beverina, Luca; Crippa, Maurizio; Sassi, Mauro; Monguzzi, Angelo; Meinardi, Francesco; Tubino, Riccardo; Pagani, Giorgio A

    2009-09-14

    We show the design and synthesis of new perfluorinated nitrosopyrazolone-based ligands and the original method employed for their complexation of erbium ions in the presence of the co-ligand perfluorotriphenylphosphine oxide; the resulting chelate is non-hygroscopic, solution processable and possesses a NIR emission with lifetimes as long as 16 micros.

  12. PERFLUORINATED COMPOUNDS IN THE CAPE FEAR DRAINAGE BASIN IN NORTH CAROLINA

    EPA Science Inventory

    Concern over perfluorinated organic compounds (PFCs), e.g., perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), is due to a number of recent studies which show that the PFCs are persistent, bioaccumulative, and toxic. Despite sustained interest in this topic, lit...

  13. Serum concentrations of perfluorinated compounds (PFC) among selected populations of children and Adults in California

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have been widely used in industrial applications and consumer products. Their persistent nature and potential health impacts are of concern. Given the high cost of collecting serum samples, this study is to understand whether we can quantify PFC se...

  14. Synthesis of multi ring-fused 2-pyridones via an acyl-ketene imine cyclocondensation.

    PubMed

    Pemberton, Nils; Jakobsson, Lotta; Almqvist, Fredrik

    2006-03-02

    Polycyclic ring-fused 2-pyridones (5a-e and 9a-e) have been prepared via a microwave-assisted acyl-ketene imine cyclocondensation. Starting from 3,4-dihydroisoquinolines (4a-b) or 3,4-dihydroharman (8), fused 2-pyridones could be prepared in a one-step procedure. By using either Meldrum's acid derivatives (1a-d) or 1,3-dioxine-4-ones (7a-b) as acyl-ketene sources, mono- or disubstitution of the fused 2-pyridone ring could be accomplished. As an application of the method, a formal synthesis of the indole alkaloid sempervilam was performed.

  15. Determination of an Effective Perfluorinated Compounds (PFCs) Oxidation Method

    NASA Astrophysics Data System (ADS)

    Siriwardena, D. P.; Crimi, M.; Holsen, T.; Bellona, C.

    2014-12-01

    Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are a stable synthetic class of chemicals ubiquitously spread in environmental media (i.e. air, soil, biota, surface water and groundwater). The substances' strong polar carbon-fluorine bonds and their high thermal and chemical stability make them resistant to biological, chemical, and physical degradation. The purpose of this research is to identify the most effective oxidation method to treat perfluorinated compounds (PFCs) and their by-products that is suitable for in situ application. The laboratory oxidation study focuses on the more commonly detected and studied long-chain (C-8) PFAS; perfluorooctanoic acids (PFOA) and perfluorooctane sulfonic acid (PFOS). Existing research evaluating oxidizing treatment effectiveness on perfluoroalkyl sulfoinoic acids (PFSAs) is limited. A review of the literature and results from preliminary studies indicate that activated persulfate and catalyzed hydrogen peroxide propagation (CHP) reactions appear to be promising oxidants for PFOA. It has been demonstrated that the reactivity of superoxide in water increases in the presence of hydrogen peroxide (H2O2) and solids. Superoxide generated in CHP reactions degrades PFOA seemingly similar to superoxide-mediated destruction of the perhalogenated compounds.The goal of this study is to look at conditions that promote generation of superoxide and look at PFASs treatment effectiveness and byproduct generation. CHP reactions are conducted with varying amount of H2O2 and Fe(III) to determine the optimum conditions for PFC degradation. Results will be compared to those of another experiment using manganese dioxide as a CHP catalyst with varied H2O2 concentration to generate superoxide to degrade PFASs. Activated persulfate conditions to be compared include alkaline pH activation, heat activation, and dual oxidation (combined H2O2 and persulfate ). This presentation will focus on a comparison of oxidation effectiveness under the

  16. Application of WWTP Biosolids and Resulting Perfluorinated Compound Contamination of Surface and Well Water in Decatur, Alabama, USA

    EPA Science Inventory

    Perfluorinated chemicals (PFCs) such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been produced and used in a wide range of industrial and consumer products for many decades. Their resistance to degradation has led to their widespread distribution in...

  17. Perfluorinated Chemicals in Surface Waters and Sediments from Northwest Georgia, USA, and Their Bioaccumulation in Lumbriculus variegatus

    EPA Science Inventory

    Concentrations of perfluorinated chemicals (PFCs) were measured in surface waters and sediments from the Coosa River watershed in northwest Georgia, USA, to examine their distribution downstream of a suspected source. Samples from eight sites were analyzed using liquid chromatogr...

  18. FUSE observations of Luminous Blue Variables

    NASA Astrophysics Data System (ADS)

    Iping, Rosina C.; Sonneborn, George; Massa, Derck L.

    P Cyg, AG Car, HD 5980 and η Car were observed with the Far Ultraviolet Spectroscopic Explorer ( FUSE) satellite. FUSE covers the spectral range from 980 Å to 1187 Å at a resolution of 0.05 Å. In this paper we discuss the far-UV properties of these LBVs and explore their similarities and differences. The FUSE observations of P Cyg and AG Car, both spectral type B2pe, are very similar. The atmospheres of both η Car and HD 5980 appear to be somewhat hotter and have much higher ionization stages (Si IV, S IV, and P V) in the FUSE spectrum than P Cyg and AG Car. There is a very good agreement between the FUSE spectrum of P Cygni and the model atmosphere computed by John Hillier with his code CMFGEN. The FUSE spectrum of η Car, however, does not agree very well with existing model spectra.

  19. Internal fuse modules for solid tantalum capacitors

    NASA Technical Reports Server (NTRS)

    Dematos, H. V.

    1981-01-01

    Miniature fuse modules were designed for and incorporated into two styles of solid tantalum capacitors. One is an epoxy molded, radial leaded, high frequency decoupling capacitor; the other is an hermetically sealed device with axial lead wires. The fusible element for both devices consists of a fine bimetallic wire which reacts exothermically upon reaching a critical temperature and then disintegrates. The desirability of having fused devices is discussed and design constraints, in particular those which minimize inductance and series resistance while optimizing fuse actuation characteristics, are reviewed. Factors affecting the amount of energy required to actuate the fuse and reliability of acuation are identified.

  20. Integrated fuses for OLED lighting device

    DOEpatents

    Pschenitzka, Florian

    2007-07-10

    An embodiment of the present invention pertains to an electroluminescent lighting device for area illumination. The lighting device is fault tolerant due, in part, to the patterning of one or both of the electrodes into strips, and each of one or more of these strips has a fuse formed on it. The fuses are integrated on the substrate. By using the integrated fuses, the number of external contacts that are used is minimized. The fuse material is deposited using one of the deposition techniques that is used to deposit the thin layers of the electroluminescent lighting device.

  1. Precise Sealing of Fused-Quartz Ampoules

    NASA Technical Reports Server (NTRS)

    Debnan, W. J. J.; Clark, I. O.

    1982-01-01

    New technique rapidly evacuates and seals fused-quartz ampoule with precise clearance over contents without appreciably thinning ampoule walls. Quartz plug is lowered into working section of ampoule after ampoule has been evacuated. Plug is then fused to ampoule walls, forming vacuum seal. New technique maintains wall strength and pumping speed.

  2. Blast Off into Space Science with Fuses.

    ERIC Educational Resources Information Center

    Bombaugh, Ruth

    2000-01-01

    Introduces an activity in which students build a fuse with steel, wood, light bulbs, copper wire, clay, and batteries. Uses the cross-age instructional approach to teach about the value of instructional time. Contains directions for building a fuse. (YDS)

  3. Electrolytic production of neodymium without perfluorinated carbon compounds on the offgases

    DOEpatents

    Keller, R.; Larimer, K.T.

    1998-09-22

    A method is described for producing neodymium in an electrolytic cell without formation of perfluorinated carbon gases (PFCs), the method comprising the steps of providing an electrolyte in the electrolytic cell and providing an anode in an anode region of the electrolyte and providing a cathode in a cathode region of the electrolytic cell. Dissolving an oxygen-containing neodymium compound in the electrolyte in the anode region and maintaining a more intense electrolyte circulation in the anode region than in the cathode region. Passing an electrolytic current between said anode and said cathode and depositing neodymium metal at the cathode, preventing the formation of perfluorinated carbon gases by limiting anode over voltage. 4 figs.

  4. Perfluorinated and Partially-Fluorinated Silane Derivatives of Perfluorooctyne: Synthesis Characterization and Chemical Reactivity

    DTIC Science & Technology

    2011-11-29

    silanes were explored. Fluorinated compounds are unique in that they are water and oil repellent , lubricative, incombustible, and chemically inert...Conference Paper 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Perfluorinated and Partially-Fluorinated Silane Derivatives of...alkynyl silane monomer represented by the formula RfSiX3 [Rf = perfluorooctyne group, X = OC2H5] was synthesized in 50% yield by nucleophilic

  5. Helsingør statement on poly- and perfluorinated alkyl substances (PFASs).

    PubMed

    Scheringer, Martin; Trier, Xenia; Cousins, Ian T; de Voogt, Pim; Fletcher, Tony; Wang, Zhanyun; Webster, Thomas F

    2014-11-01

    In this discussion paper, the transition from long-chain poly- and perfluorinated alkyl substances (PFASs) to fluorinated alternatives is addressed. Long-chain PFASs include perfluoroalkyl carboxylic acids (PFCAs) with 7 or more perfluorinated carbons, perfluoroalkyl sulfonic acids (PFSAs) with 6 or more perfluorinated carbons, and their precursors. Because long-chain PFASs have been found to be persistent, bioaccumulative and toxic, they are being replaced by a wide range of fluorinated alternatives. We summarize key concerns about the potential impacts of fluorinated alternatives on human health and the environment in order to provide concise information for different stakeholders and the public. These concerns include, amongst others, the likelihood of fluorinated alternatives or their transformation products becoming ubiquitously present in the global environment; the need for more information on uses, properties and effects of fluorinated alternatives; the formation of persistent terminal transformation products including PFCAs and PFSAs; increasing environmental and human exposure and potential of adverse effects as a consequence of the high ultimate persistence and increasing usage of fluorinated alternatives; the high societal costs that would be caused if the uses, environmental fate, and adverse effects of fluorinated alternatives had to be investigated by publicly funded research; and the lack of consideration of non-persistent alternatives to long-chain PFASs.

  6. Uptake of perfluorinated alkyl acids by hydroponically grown lettuce (Lactuca sativa).

    PubMed

    Felizeter, Sebastian; McLachlan, Michael S; de Voogt, Pim

    2012-11-06

    An uptake study was carried out to assess the potential human exposure to perfluorinated alkyl acids (PFAAs) through the ingestion of vegetables. Lettuce (Lactuca sativa) was grown in PFAA-spiked nutrient solutions at four different concentrations, ranging from 10 ng/L to 10 μg/L. Eleven perfluorinated carboxylic acids (PFCAs) and three perfluorinated sulfonic acids (PFSAs) were analyzed by HPLC-MS/MS. At the end of the experiment, the major part of the total mass of each of the PFAAs (except the short-chain, C4-C7, PFCAs) taken up by plants appeared to be retained in the nonedible part, viz. the roots. Root concentration factors (RCF), foliage/root concentration factors (FRCF), and transpiration stream concentration factors (TSCF) were calculated. For the long chained PFAAs, RCF values were highest, whereas FRCF were lowest. This indicates that uptake by roots is likely governed by sorption of PFAAs to lipid-rich root solids. Translocation from roots to shoots is restricted and highly depending on the hydrophobicity of the compounds. Although the TSCF show that longer-chain PFCAs (e.g., perfluorododecanoic acid) get better transferred from the nutrient solution to the foliage than shorter-chain PFCAs (e.g., perfluoroheptanoic acid), the major fraction of longer-chain PFCAs is found in roots due to additional adsorption from the spiked solution. Due to the strong electron-withdrawing effect of the fluorine atoms the role of the negative charge of the dissociated PFAAs is likely insignificant.

  7. Microgravity Manufacturing Via Fused Deposition

    NASA Technical Reports Server (NTRS)

    Cooper, K. G.; Griffin, M. R.

    2003-01-01

    Manufacturing polymer hardware during space flight is currently outside the state of the art. A process called fused deposition modeling (FDM) can make this approach a reality by producing net-shaped components of polymer materials directly from a CAE model. FDM is a rapid prototyping process developed by Stratasys, Inc.. which deposits a fine line of semi-molten polymer onto a substrate while moving via computer control to form the cross-sectional shape of the part it is building. The build platen is then lowered and the process is repeated, building a component directly layer by layer. This method enables direct net-shaped production of polymer components directly from a computer file. The layered manufacturing process allows for the manufacture of complex shapes and internal cavities otherwise impossible to machine. This task demonstrated the benefits of the FDM technique to quickly and inexpensively produce replacement components or repair broken hardware in a Space Shuttle or Space Station environment. The intent of the task was to develop and fabricate an FDM system that was lightweight, compact, and required minimum power consumption to fabricate ABS plastic hardware in microgravity. The final product of the shortened task turned out to be a ground-based breadboard device, demonstrating miniaturization capability of the system.

  8. Laser welding of fused quartz

    DOEpatents

    Piltch, Martin S.; Carpenter, Robert W.; Archer, III, McIlwaine

    2003-06-10

    Refractory materials, such as fused quartz plates and rods are welded using a heat source, such as a high power continuous wave carbon dioxide laser. The radiation is optimized through a process of varying the power, the focus, and the feed rates of the laser such that full penetration welds may be accomplished. The process of optimization varies the characteristic wavelengths of the laser until the radiation is almost completely absorbed by the refractory material, thereby leading to a very rapid heating of the material to the melting point. This optimization naturally occurs when a carbon dioxide laser is used to weld quartz. As such this method of quartz welding creates a minimum sized heat-affected zone. Furthermore, the welding apparatus and process requires a ventilation system to carry away the silicon oxides that are produced during the welding process to avoid the deposition of the silicon oxides on the surface of the quartz plates or the contamination of the welds with the silicon oxides.

  9. Single connector provides safety fuses for multiple lines

    NASA Technical Reports Server (NTRS)

    Weber, G. J.

    1966-01-01

    Fuse-bearing sleeve which is inserted between the male and female members of a multiple-line connector contains a safety fuse for each pin of the connector assembly. The sleeve is easily and quickly opened for fuse replacement.

  10. Fused Silica and Other Transparent Window Materials

    NASA Technical Reports Server (NTRS)

    Salem, Jon

    2016-01-01

    Several transparent ceramics, such as spinel and AlONs are now being produced in sufficient large areas to be used in space craft window applications. The work horse transparent material for space missions from Apollo to the International Space Station has been fused silica due in part to its low coefficient of expansion and optical quality. Despite its successful use, fused silica exhibits anomalies in its crack growth behavior, depending on environmental preconditioning and surface damage. This presentation will compare recent optical ceramics to fused silica and discuss sources of variation in slow crack growth behavior.

  11. Fluorine-Based DRIE of Fused Silica

    NASA Technical Reports Server (NTRS)

    Yee, Karl; Shcheglov, Kirill; Li, Jian; Choi, Daniel

    2007-01-01

    A process of deep reactive-ion etching (DRIE) using a fluorine-based gas mixture enhanced by induction-coupled plasma (ICP) has been demonstrated to be effective in forming high-aspect-ratio three-dimensional patterns in fused silica. The patterns are defined in part by an etch mask in the form of a thick, high-quality aluminum film. The process was developed to satisfy a need to fabricate high-aspect-ratio fused-silica resonators for vibratory microgyroscopes, and could be used to satisfy similar requirements for fabricating other fused-silica components.

  12. Organometallic chemistry: Fused ferrocenes come full circle

    NASA Astrophysics Data System (ADS)

    Musgrave, Rebecca A.; Manners, Ian

    2016-09-01

    Chemists have long been fascinated by electron delocalization, from both a fundamental and applied perspective. Macrocyclic oligomers containing fused ferrocenes provide a new structural framework -- containing strongly interacting metal centres -- that is capable of supporting substantial charge delocalization.

  13. Coordination chemistry in fused-salt solutions

    NASA Technical Reports Server (NTRS)

    Gruen, D. M.

    1969-01-01

    Spectrophotometric work on structural determinations with fused-salt solutions is reviewed. Constraints placed on the method, as well as interpretation of the spectra, are discussed with parallels drawn to aqueous spectrophotometric curves of the same materials.

  14. Process for energy reduction with flash fusing

    SciTech Connect

    Berkes, J.S.

    1987-10-06

    This patent describes a process for affecting a reduction in the energy needed for accomplishing the flash fusing of a developed image which comprises (1) providing a toner composition with resin particles, pigment articles, and wax. The wax possesses a lower melting temperature than the resin particles and is selected from the group consisting of polyethylene and polypropylene with a molecular weight of less than about 6,000; (2) introducing the aforementioned toner composition into a xerographic imaging apparatus having incorporated therein a flash fusing device; (3) generating an electrostatic latent image in the imaging apparatus, and subsequently developing this image with the toner composition; (4) transferring the image to a supporting substrate; and (5) permanently attaching the image to the substrate with energy emitted from a flash fusing device, and wherein there is formed between the supporting substrate and the toner composition during fusing a wax layer.

  15. RHEOLOGICAL PROPERTIES & MOLECULAR WEIGHT DISTRIBUTIONS OF FOUR PERFLUORINATED THERMOPLASTIC POLYMERS

    SciTech Connect

    Hoffman, D M; Shields, A L

    2009-02-24

    Dynamic viscosity measurements and molecular weight estimates have been made on four commercial, amorphous fluoropolymers with glass transitions (Tg) above 100 C: Teflon AF 1600, Hyflon AD 60, Cytop A and Cytop M. These polymers are of interest as binders for the insensitive high explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) because of their high density and Tg above ambient, but within a suitable processing range of TATB. As part of this effort, the rheological properties and molecular weight distributions of these polymers were evaluated.

  16. Fused Bead Analysis of Diogenite Meteorites

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D.W.; Beck, B.W.; McSween, H.Y.; Lee, C.T. A.

    2009-01-01

    Bulk rock chemistry is an essential dataset in meteoritics and planetary science [1]. A common method used to obtain the bulk chemistry of meteorites is ICP-MS. While the accuracy, precision and low detection limits of this process are advantageous [2], the sample size used for analysis (approx.70 mg) can be a problem in a field where small and finite samples are the norm. Fused bead analysis is another bulk rock analytical technique that has been used in meteoritics [3]. This technique involves forming a glass bead from 10 mg of sample and measuring its chemistry using a defocused beam on a microprobe. Though the ICP-MS has lower detection limits than the microprobe, the fused bead method destroys a much smaller sample of the meteorite. Fused bead analysis was initially designed for samples with near-eutectic compositions and low viscosities. Melts generated of this type homogenize at relatively low temperatures and produce primary melts near the sample s bulk composition [3]. The application of fused bead analysis to samples with noneutectic melt compositions has not been validated. The purpose of this study is to test if fused bead analysis can accurately determine the bulk rock chemistry of non-eutectic melt composition meteorites. To determine this, we conduct two examinations of the fused bead. First, we compare ICP-MS and fused bead results of the same samples using statistical analysis. Secondly, we inspect the beads for the presence of crystals and chemical heterogeneity. The presence of either of these would indicate incomplete melting and quenching of the bead.

  17. Modification of epoxy-reinforced glass-cloth composites with a perfluorinated alkyl ether elastomer

    NASA Technical Reports Server (NTRS)

    Rosser, R. W.; Chen, T. S.; Taylor, M.

    1984-01-01

    A perfluorinated alkyl ether diacyl fluoride prepolymer (molecular weight about 1500) was coreacted with Epon 828 epoxy resin and diamino diphenyl sulfone to obtain an elastomer-toughened, glass-cloth composite. Improvements in flexural toughness, impact resistance, and water resistance, without loss of strength, modulus of elasticity or a lowering of the glass-transition temperature, were realized over those of the unmodified composite. Factors concerning optimization of the process are discussed. Results suggest that a simultaneously interpenetrating polymer network may be formed which gives rise to a measured improvement in composite mechanical properties.

  18. The application of Dow Chemical's perfluorinated membranes in proton-exchange membrane fuel cells

    NASA Technical Reports Server (NTRS)

    Eisman, G. A.

    1989-01-01

    Dow Chemical's research activities in fuel cell devices revolves around the development and subsequent investigation of the perfluorinated inomeric membrane separator useful in proton-exchange membrane systems. Work is currently focusing on studying the effects of equivalent weight, thickness, water of hydration, pretreatment procedures, as well as the degree of water management required for a given membrane separator in the cell. The presentation will include details of certain aspects of the above as well as some of the requirements for high and low power generation.

  19. Wafer-fused semiconductor radiation detector

    DOEpatents

    Lee, Edwin Y.; James, Ralph B.

    2002-01-01

    Wafer-fused semiconductor radiation detector useful for gamma-ray and x-ray spectrometers and imaging systems. The detector is fabricated using wafer fusion to insert an electrically conductive grid, typically comprising a metal, between two solid semiconductor pieces, one having a cathode (negative electrode) and the other having an anode (positive electrode). The wafer fused semiconductor radiation detector functions like the commonly used Frisch grid radiation detector, in which an electrically conductive grid is inserted in high vacuum between the cathode and the anode. The wafer-fused semiconductor radiation detector can be fabricated using the same or two different semiconductor materials of different sizes and of the same or different thicknesses; and it may utilize a wide range of metals, or other electrically conducting materials, to form the grid, to optimize the detector performance, without being constrained by structural dissimilarity of the individual parts. The wafer-fused detector is basically formed, for example, by etching spaced grooves across one end of one of two pieces of semiconductor materials, partially filling the grooves with a selected electrical conductor which forms a grid electrode, and then fusing the grooved end of the one semiconductor piece to an end of the other semiconductor piece with a cathode and an anode being formed on opposite ends of the semiconductor pieces.

  20. OPUS: the FUSE science data pipeline

    NASA Astrophysics Data System (ADS)

    Rose, James F.; Heller-Boyer, C.; Rose, M. A.; Swam, M.; Miller, W.; Kriss, G. A.; Oegerle, William R.

    1998-07-01

    This paper describes how the OPUS pipeline, currently used for processing science data from the Hubble Space Telescope (HST), was used as the backbone for developing the science data pipeline for a much smaller mission. The far ultraviolet spectroscopic explorer (FUSE) project selected OPUS for its data processing pipeline platform and selected the OPUS team at the STScI to write the FUSE pipeline applications. A total of 105 new modules were developed for the FUSE pipeline. The foundation of over 250 modules in the OPUS libraries allowed development to proceed quickly and with considerable confidence that the underlying functionality is reliable and robust. Each task represented roughly 90 percent reuse, and the project as a whole shows over 70 percent reuse of the existing OPUS system. Taking an existing system that is operational, and will be maintained for many years to come, was a key decision for the FUSE mission. Adding the extensive experience of the OPUS team to the task resulted in the development of a complete telemetry pipeline system within a matter of months. Reusable software has been the siren song of software engineering and object- oriented design for a decade or more. The development of inexpensive software systems by adapting existing code to new applications is as attractive as it has been elusive. The OPUS telemetry pipeline for the FUSE mission has proven to be a significant exception to that trend.

  1. Determination of perfluorinated surfactants in surface water samples by two independent analytical techniques: liquid chromatography/tandem mass spectrometry and 19F NMR.

    PubMed

    Moody, C A; Kwan, W C; Martin, J W; Muir, D C; Mabury, S A

    2001-05-15

    Perfluorinated surfactants are an important class of specialty chemicals that have received recent attention as a result of their persistence in the environment. Two analytical methods for the determination of perfluorinated surfactants in aqueous samples were developed in order to investigate a spill of 22000 L of fire retardant foam containing perfluorinated surfactants into Etobicoke Creek (Toronto, Ontario). With the first method, aliquots of surface water (0.2-200 mL) were preconcentrated using solid-phase extraction. Liquid chromatography/tandem mass spectrometry was employed for identification and quantification of each perfluorinated surfactant. Total perfluorinated surfactant concentrations in surface water samples ranged from 0.011 to 2270 microg/L, and perfluorooctanesulfonate was the predominant surfactant observed. Interestingly, perfluorooctanoate was detected in surface water sampled upstream of the spill. A second method employing 19F NMR was developed for the determination of total perfluorinated surfactant concentrations in aqueous samples (2-100 mL). By 19F NMR, the surface water concentrations ranged from nondetect (method detection limit, 10 microg/L for a 100-mL sample) to 17000 microg/L. These methods permit comprehensive evaluation of aqueous samples for the presence of perfluorinated surfactants and have applicability to other sample matrixes.

  2. Fused silica windows for solar receiver applications

    NASA Astrophysics Data System (ADS)

    Hertel, Johannes; Uhlig, Ralf; Söhn, Matthias; Schenk, Christian; Helsch, Gundula; Bornhöft, Hansjörg

    2016-05-01

    A comprehensive study of optical and mechanical properties of quartz glass (fused silica) with regard to application in high temperature solar receivers is presented. The dependence of rupture strength on different surface conditions as well as high temperature is analyzed, focussing particularly on damage by devitrification and sandblasting. The influence of typical types of contamination in combination with thermal cycling on the optical properties of fused silica is determined. Cleaning methods are compared regarding effectiveness on contamination-induced degradation for samples with and without antireflective coating. The FEM-aided design of different types of receiver windows and their support structure is presented. A large-scale production process has been developed for producing fused silica dome shaped windows (pressurized window) up to a diameter of 816 mm. Prototypes were successfully pressure-tested in a test bench and certified according to the European Pressure Vessel Directive.

  3. Propagation mechanism of polymer optical fiber fuse

    PubMed Central

    Mizuno, Yosuke; Hayashi, Neisei; Tanaka, Hiroki; Nakamura, Kentaro; Todoroki, Shin-ichi

    2014-01-01

    A fiber fuse phenomenon in polymer optical fibers (POFs) has recently been observed, and its unique properties such as slow propagation, low threshold power density, and the formation of a black oscillatory damage curve, have been reported. However, its characterization is still insufficient to well understand the mechanism and to avoid the destruction of POFs. Here, we present detailed experimental and theoretical analyses of the POF fuse propagation. First, we clarify that the bright spot is not a plasma but an optical discharge, the temperature of which is ~3600 K. We then elucidate the reasons for the oscillation of the damage curve along with the formation of newly-observed gas bubbles as well as for the low threshold power density. We also present the idea that the POF fuse can potentially be exploited to offer a long photoelectric interaction length. PMID:24762949

  4. 200 kj copper foil fuses. Final report

    SciTech Connect

    McClenahan, C.R.; Goforth, J.H.; Degnan, J.H.; Henderson, R.M.; Janssen, W.H.

    1980-04-01

    A 200-kJ, 50-kV capacitor bank has been discharged into 1-mil-thick copper foils immersed in fine glass beads. These foils ranged in length from 27 to 71 cm and in width from 15 to 40 cm. Voltage spikes of over 250 kV were produced by the resulting fuse behavior of the foil. Moreover, the current turned off at a rate that was over 6 times the initial bank dI/dt. Full widths at half maxima for the voltage and dI/dt spikes were about 0.5 microsec, with some as short as 300 nanosec. Electrical breakdown was prevented in all but one size fuze with maximum applied fields of 7 kV/cm. Fuses that were split into two parallel sections have been tested, and the effects relative to one-piece fuses are much larger than would be expected on the basis of inductance differences alone. A resistivity model for copper foil fuses, which differs from previous work in that it includes a current density dependence, has been devised. Fuse behavior is predicted with reasonable accuracy over a wide range of foil sizes by a quasi-two-dimensional fuse code that incorporates this resistivity model. A variation of Maisonnier's method for predicting optimum fuze size has been derived. This method is valid if the risetime of the bank exceeds 3 microsec, in which case it can be expected to be applicable over a wide range of peak current densities.

  5. Liquid-liquid interfaces of semifluorinated alkane diblock copolymers with water, alkanes, and perfluorinated alkanes.

    SciTech Connect

    Perahia, Dvora, Dr.; Pierce, Flint; Tsige, Mesfin; Grest, Gary Stephen, Dr.

    2008-08-01

    The liquid-liquid interface between semifluorinated alkane diblock copolymers of the form F3C(CF2)n-1-(CH2)m-1CH3 and water, protonated alkanes, and perfluorinated alkanes are studied by fully atomistic molecular dynamics simulations. A modified version of the OPLS-AA (Optimized Parameter for Liquid Simulation All-Atom) force field of Jorgensen et al. has been used to study the interfacial behavior of semifluorinated diblocks. Aqueous interfaces are found to be sharp, with correspondingly large values of the interfacial tension. Due to the reduced hydrophobicity of the protonated block compared to the fluorinated block, hydrogen enhancement is observed at the interface. Water dipoles in the interfacial region are found to be oriented nearly parallel to the liquid-liquid interface. A number of protonated alkanes and perfluorinated alkanes are found to be mutually miscible with the semifluorinated diblocks. For these liquids, interdiffusion follows the expected Fickian behavior, and concentration-dependent diffusivities are determined.

  6. Liquid-liquid interfaces of semifluorinated alkane diblock copolymers with water, alkanes, and perfluorinated alkanes.

    PubMed

    Pierce, Flint; Tsige, Mesfin; Perahia, Dvora; Grest, Gary S

    2008-12-18

    The liquid-liquid interface between semifluorinated alkane diblock copolymers of the form F3C(CF2)n-1-(CH2)m-1CH3 and water, protonated alkanes, and perfluorinated alkanes are studied by fully atomistic molecular dynamics simulations. A modified version of the OPLS-AA (Optimized Parameter for Liquid Simulation All-Atom) force field of Jorgensen et al. has been used to study the interfacial behavior of semifluorinated diblocks. Aqueous interfaces are found to be sharp, with correspondingly large values of the interfacial tension. Due to the reduced hydrophobicity of the protonated block compared to the fluorinated block, hydrogen enhancement is observed at the interface. Water dipoles in the interfacial region are found to be oriented nearly parallel to the liquid-liquid interface. A number of protonated alkanes and perfluorinated alkanes are found to be mutually miscible with the semifluorinated diblocks. For these liquids, interdiffusion follows the expected Fickian behavior, and concentration-dependent diffusivities are determined.

  7. QSAR classification models for the screening of the endocrine-disrupting activity of perfluorinated compounds.

    PubMed

    Kovarich, S; Papa, E; Li, J; Gramatica, P

    2012-01-01

    Perfluorinated compounds (PFCs) are a class of emerging pollutants still widely used in different materials as non-adhesives, waterproof fabrics, fire-fighting foams, etc. Their toxic effects include potential for endocrine-disrupting activity, but the amount of experimental data available for these pollutants is limited. The use of predictive strategies such as quantitative structure-activity relationships (QSARs) is recommended under the REACH regulation, to fill data gaps and to screen and prioritize chemicals for further experimentation, with a consequent reduction of costs and number of tested animals. In this study, local classification models for PFCs were developed to predict their T4-TTR (thyroxin-transthyretin) competing potency. The best models were selected by maximizing the sensitivity and external predictive ability. These models, characterized by robustness, good predictive power and a defined applicability domain, were applied to predict the activity of 33 other PFCs of environmental concern. Finally, classification models recently published by our research group for T4-TTR binding of brominated flame retardants and for estrogenic and anti-androgenic activity were applied to the studied perfluorinated chemicals to compare results and to further evaluate the potential for these PFCs to cause endocrine disruption.

  8. Proton exchange membranes based on the short-side-chain perfluorinated ionomer

    NASA Astrophysics Data System (ADS)

    Ghielmi, A.; Vaccarono, P.; Troglia, C.; Arcella, V.

    Due to the renovated availability of the base monomer for the synthesis of the short-side-chain (SSC) perfluorinated ionomer, fuel cell membrane development is being pursued using this well known ionomer structure, which was originally developed by Dow in the 1980s. The new membranes under development have the trade name Hyflon Ion. After briefly reviewing the literature on the Dow ionomer, new characterization data are reported on extruded Hyflon Ion membranes. The data are compared to those available in the literature on the Dow SSC ionomer and membranes. Comparison is made also with data obtained in this work or available in the literature on the long-side-chain (LSC) perfluorinated ionomer (Nafion). Thermal, visco-elastic, water absorption and mechanical properties of Hyflon Ion are studied. While the general behavior is similar to that shown in the past by the Dow membranes, slight differences are evident in the hydration behavior at equivalent weight (EW) < 900, probably due to different EW distributions. Measurements on dry membranes confirm that Hyflon Ion has a higher glass transition temperature compared to Nafion, which makes it a more promising material for high temperature proton exchange membrane (PEM) fuel cell operation ( T > 100 °C). Beginning of life fuel cell performance has also been confirmed to be higher than that given by a Nafion membrane of equal thickness.

  9. Acoustic Cavitation: A Potential Remediation Technology for On-Site Elimination of Perfluorinated Contaminants

    NASA Astrophysics Data System (ADS)

    Vecitis, C. D.; Cheng, J.; Park, H.; Hoffmann, M. R.

    2006-12-01

    Perfluorinated chemicals are emerging as globally ubiquitous contaminants which are recalcitrant to the conventional remediation techniques of adsorption and chemical oxidation. The release of these chemicals to the environment occurs from specific sites such as manufacturing plants, fire-fighting foams at airports and contaminated landfills. Even though these compounds are widely recognized as potentially hazardous, disposal regulations have been limited due to the ineffectiveness of current pump and treat technologies towards these species. We have shown that ultrasonically induced acoustic cavitation can effectively mineralize aqueous perfluorinated acid and sulfonate species by in situ pyrolysis and chemical oxidation at the lab and pilot scale. Efficiency has been tested on a variety of matrices such as tap water, groundwater and landfill pump-out with VOC content being the major detriment towards remediation. Advanced oxidation by the simultaneously application of ozone and ultrasound seems to partially eliminate this barrier by enhancing the rate of VOC mineralization. Application of this technology to a contaminated field site and the obstacles of scaling to such a degree are discussed.

  10. Bioaccumulation and trophic transfer of perfluorinated compounds in a eutrophic freshwater food web.

    PubMed

    Xu, Jian; Guo, Chang-Sheng; Zhang, Yuan; Meng, Wei

    2014-01-01

    In this study, the bioaccumulation of perfluorinated compounds from a food web in Taihu Lake in China was investigated. The organisms included egret bird species, carnivorous fish, omnivorous fish, herbivorous fish, zooplankton, phytoplankton, zoobenthos and white shrimp. Isotope analysis by δ(13)C and δ(15)N indicated that the carnivorous fish and egret were the top predators in the studied web, occupying trophic levels intermediate between 3.66 and 4.61, while plankton was at the lowest trophic level. Perfluorinated carboxylates (PFCAs) with 9-12 carbons were significantly biomagnified, with trophic magnification factors (TMFs) ranging from 2.1 to 3.7. The TMF of perfluorooctane sulfonate (PFOS) (2.9) was generally comparable to or lower than those of the PFCAs in the same food web. All hazard ratio (HR) values reported for PFOS and perfluorooctanoate (PFOA) were less than unity, suggesting that the detected levels would not cause any immediate health effects to the people in Taihu Lake region through the consumption of shrimps and fish.

  11. 1,3,5-Trinitrobenzene

    Integrated Risk Information System (IRIS)

    1,3,5 - Trinitrobenzene ; CASRN 99 - 35 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcino

  12. Spatial and Temporal Patterns in Concentrations of Perfluorinated Compounds in Bald Eagle Nestlings in the Upper Midwestern United States

    EPA Science Inventory

    Perfluorinated chemicals (PFCs) are of concern due to their widespread use, persistence in the environment, tendency to accumulate in animal tissues, and growing evidence of toxicity. Between 2006 and 2011 we collected blood plasma from 261 bald eagle nestlings in six study areas...

  13. Helicopter Aircrew Training Using Fused Reality

    DTIC Science & Technology

    2006-06-01

    RTO-MP-HFM-136 27 - 1 Helicopter Aircrew Training Using Fused Reality Dr. Ed Bachelder Systems Technology Inc. 13766 Hawthorne Blvd...applied to training helicopter aircrew personnel using a prototype simulator, the Prototype Aircrew Virtual Environment Training (PAVET) System...cabin) pixels using blue screen imaging techniques. This bitmap is overlaid on a virtual environment, and sent Bachelder, E. (2006) Helicopter Aircrew

  14. Crystal growth in fused solvent systems

    NASA Technical Reports Server (NTRS)

    Ulrich, D. R.; Noone, M. J.; Spear, K. E.; White, W. B.; Henry, E. C.

    1973-01-01

    Research is reported on the growth of electronic ceramic single crystals from solution for the future growth of crystals in a microgravity environment. Work included growth from fused or glass solvents and aqueous solutions. Topics discussed include: crystal identification and selection; aqueous solution growth of triglycine sulphate (TGS); and characterization of TGS.

  15. Fused thiophene derivatives as MEK inhibitors.

    PubMed

    Laing, Victoria E; Brookings, Daniel C; Carbery, Rachel J; Simorte, Jose Gascon; Hutchings, Martin C; Langham, Barry J; Lowe, Martin A; Allen, Rodger A; Fetterman, Joanne R; Turner, James; Meier, Christoph; Kennedy, Jeff; Merriman, Mark

    2012-01-01

    A number of novel fused thiophene derivatives have been prepared and identified as potent inhibitors of MEK. The SAR data of selected examples and the in vivo profiling of compound 13 h demonstrates the functional activity of this class of compounds in HT-29 PK/PD models.

  16. Perfluorinated carboxylic and sulphonic acids in surface water media from the regions of Tibetan Plateau: Indirect evidence on photochemical degradation?

    PubMed

    Yamazaki, Eriko; Falandysz, Jerzy; Taniyasu, Sachi; Hui, Ge; Jurkiewicz, Gabriela; Yamashita, Nobuyoshi; Yang, Yong-Liang; Lam, Paul K S

    2016-01-01

    Perfluorinated surfactants and repellents are synthetic substances that have found numerous industrial and customer applications. Due to their persistence, at least two groups of these substances-perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonic acids (PFSAs)-are diffused widely in the environment. It is hypothesized that the Tibetan Plateau, is one of few unique places on the Earth, due to its topography, specifically the vast space and high elevation above sea level, geographic location, climate, high solar radiation, lack of industry, little urbanization and general lack of significant direct sources of pollution. There it is believed possible to gain an insight into atmospheric fate (possible photochemical degradation of higher molecular mass and formation of lower molecular mass PFCAs and PFSAs) of PFASs under un-disturbed environmental conditions. Ultratrace analytical method for PFCAs and PFSAs and use of transportation and field blanks, laboratory blanks and isotopically labelled surrogates for recovery control has allowed the determination of nine perfluorinated carboxylic acids and six perfluorinated sulfonic acids at ultra-trace levels in water based samples from the alpine dimension regions of the Tibetan Plateau, the eastern slope of Minya Konka peak at the eastern edge of the Tibetan Plateau, and also from the city of Chengdu from the lowland of the Sichuan Province in China. The specific compositional pattern of PFCAs and PFSAs and low levels of pollution with those compounds were observed in the central region of the Tibetan Plateau and in the region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau. The fingerprint of the compositional pattern of PFCAs and PFSAs in water samples in the central region of the Tibetan Plateau and in the alpine region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau may be explained by the result of photochemical degradation with dealkylation of longer chain

  17. INHIBITION OF GAP JUNCTIONAL INTERCELLULAR COMMUNICATION BY PERFLUORINATED COMPOUNDS IN RAT LIVER AND DOLPHIN KIDNEY EPITHELIAL CELL LINES IN VITRO AND SPRAGUE-DAWLEY RATS IN VIVO

    EPA Science Inventory

    Abstract

    Gap Junctional Intercellular Communication (GJIC) is the major pathway of intercellular signal transduction, and is, thus, important for normal cell growth and function. Recent studies have revealed a global distribution of some perfluorinated organic compounds e...

  18. Levels and trends of poly- and perfluorinated compounds in the arctic environment.

    PubMed

    Butt, Craig M; Berger, Urs; Bossi, Rossana; Tomy, Gregg T

    2010-07-01

    Poly- and perfluorinated organic compounds (PFCs) are ubiquitous in the Arctic environment. Several modeling studies have been conducted in attempt to resolve the dominant transport pathway of PFCs to the arctic-atmospheric transport of precursors versus direct transport via ocean currents. These studies are generally limited by their focus on perfluorooctanoate (PFOA) fluxes to arctic seawater and thus far have only used fluorotelomer alcohols (FTOHs) and sulfonamide alcohols as inputs for volatile precursors. There have been many monitoring studies from the North American and European Arctic, however, almost nothing is known about PFC levels from the Russian Arctic. In general, there are very few measurements of PFCs from the abiotic environment. Atmospheric measurements show the widespread occurrence of PFC precursors, FTOHs and perfluorinated sulfonamide alcohols. Further, PFCAs and PFSAs have been detected on atmospheric particles. The detection of PFCAs and PFSAs in snow deposition is consistent with the volatile precursor transport hypothesis. There are very limited measurements of PFCs in seawater. PFOA is generally detected in the greatest concentrations. Additional seawater measurements are needed to validate existing model predications. The bulk of the monitoring efforts in biological samples have focused on the perfluorinated carboxylates (PFCAs) and sulfonates (PFSAs), although there are very few measurements of PFC precursors. The marine food web has been well studied, particularly the top predators. In contrast, freshwater and terrestrial ecosystems have been poorly studied. Studies show that in wildlife perfluorooctane sulfonate (PFOS) is generally measured in the highest concentration, followed by either perfluorononanoate (PFNA) or perfluoroundecanoate (PFUnA). However, some whale species show relatively high levels of perfluorooctane sulfonamide (PFOSA) and seabirds are typically characterized by high proportions of the C(11)-C(15) PFCAs. PFOA is

  19. [Pollution Characteristics of Perfluorinated Compounds in Offshore Marine Area of Shenzhen].

    PubMed

    Liu, Bao-lin; Zhang, Hong; Xie, Liu-wei; Liu, Guo-qing; Wang, Yan-ping; Wang, Xin-xuan; Li, Jing; Dong, Wei-hua

    2015-06-01

    In order to explore the pollution characteristics of perfluorinated compounds (PFCs), 10 surface seawaters and 7 surface sediments were collected in offshore marine area of Shenzhen (offshore distance >2 km) in September 2013. All the samples were prepared by solid-phase extraction and analyzed using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/ MS). The results showed that 10 PFCs, including C4, C6 and C8 perfluorinated sulfonates (PFSAs) and C5-C11, perfluorinated carboxylic acids (PFCAs) were detected in the surface waters. ∑ PFC concentrations ranged from 1.74 ng x L(-1) to 14.7 ng x L(-1) with PFBS, PFOS and PFOA being the dominant compounds. The spatial distribution of ∑ PFC concentrations displayed the characteristic of "the west being higher than the east", with ∑ PFC concentrations of Lingding Sea and Shenzhen Bay being higher than those of Daya Bay and Dapeng Bay (P < 0.05). The farther the sampling location was from the shore, the lower the ∑ PFC concentrations were. Direct sewage emissions and rivers emptying into the sea might be the primary sources of PFCs in the surface seawaters. 8 PFCs, including C6 and C8 PFSAs and C5, C6, and C8-C11 PFCAs were detected in the surface sediments. ∑ PFC concentrations ranged from 2.22 micorg x kg(-1) to 2.62 microg x kg(-1) with PFOS being the dominant compounds. There was a small change of ∑ PFC concentrations in surface sediments, which might be contributed by the adsorption from overlying water. The adsorption of PFCs on sediment significantly increased with the increasing length of carbon chain, and the adsorption of PFSA was higher than that of PFCA with the same length of carbon chain as PFSA. Additionally, the comparison with other seawater PFC measurements showed high PFBS pollution in this study, whereas the level of PFOS in sediment was close to those of other studies.

  20. Transmitting and reflecting diffuser. [using ultraviolet grade fused silica coatings

    NASA Technical Reports Server (NTRS)

    Keafer, L. S., Jr.; Burcher, E. E.; Kopia, L. P. (Inventor)

    1977-01-01

    An ultraviolet grade fused silica substrate is coated with vaporized fused silica. The coating thickness is controlled, one thickness causing ultraviolet light to diffuse and another thickness causing ultraviolet light to reflect a near Lambertian pattern.

  1. Cam-operated limit switch features safe fuse replacement

    NASA Technical Reports Server (NTRS)

    Weber, G. J.

    1965-01-01

    Two hermetically sealed, short travel, limit switches permit fuse replacement without danger of a spark or arcing. The switches are wired in parallel circuits and actuated by manually operated cams containing the circuit fuses.

  2. 29 CFR 1926.907 - Use of safety fuse.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... way shall be forbidden. (b) The hanging of a fuse on nails or other projections which will cause a... destroyed. (f) No fuse shall be capped, or primers made up, in any magazine or near any possible source...

  3. 29 CFR 1926.907 - Use of safety fuse.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... way shall be forbidden. (b) The hanging of a fuse on nails or other projections which will cause a... destroyed. (f) No fuse shall be capped, or primers made up, in any magazine or near any possible source...

  4. Multimodal plasmonics in fused colloidal networks

    NASA Astrophysics Data System (ADS)

    Teulle, Alexandre; Bosman, Michel; Girard, Christian; Gurunatha, Kargal L.; Li, Mei; Mann, Stephen; Dujardin, Erik

    2015-01-01

    Harnessing the optical properties of noble metals down to the nanometre scale is a key step towards fast and low-dissipative information processing. At the 10-nm length scale, metal crystallinity and patterning as well as probing of surface plasmon properties must be controlled with a challenging high level of precision. Here, we demonstrate that ultimate lateral confinement and delocalization of surface plasmon modes are simultaneously achieved in extended self-assembled networks comprising linear chains of partially fused gold nanoparticles. The spectral and spatial distributions of the surface plasmon modes associated with the colloidal superstructures are evidenced by performing monochromated electron energy-loss spectroscopy with a nanometre-sized electron probe. We prepare the metallic bead strings by electron-beam-induced interparticle fusion of nanoparticle networks. The fused superstructures retain the native morphology and crystallinity but develop very low-energy surface plasmon modes that are capable of supporting long-range and spectrally tunable propagation in nanoscale waveguides.

  5. Fast Color Change with Photochromic Fused Naphthopyrans.

    PubMed

    Sousa, Céu M; Berthet, Jerome; Delbaere, Stephanie; Polónia, André; Coelho, Paulo J

    2015-12-18

    Photochromic molecules can reversibly develop color upon irradiation with UV light. These smart molecules, mainly in the naphthopyran family, have been applied with success to ophthalmic lenses that darken quickly under sunlight and revert to the uncolored state after several minutes in the dark. This slow adaptation to the absence of light is one of the limitations and is due to the formation of an unwanted photoisomer. We have designed a new naphthopyran with a bridged structure which prohibits the formation of the undesirable, persistent photoisomer and thus shows a very fast switching between the uncolored and colored states. UV irradiation of a hybrid siloxane matrix doped with the new fused naphthopyran leads to the formation of a pink coloration bleaching in a few milliseconds, in the absence of light, at room temperature. This new fused naphthopyran is easily prepared in three steps from readily accessible precursors and is amenable to structural modifications to tailor color and lifetime of the colored photoisomer.

  6. Periclase-chromite refractories from fused materials

    SciTech Connect

    Slovikovskii, V.V.; Eroshkina, V.I.; Kononenko, G.V.; Nechistykh, G.A.; Simonov, K.V.

    1985-11-01

    Experiments were carried out to obtain high-grade fused chromitepericlase. It is shown that during the melting of batch consisting of raw magnesite and chromite ore the process of reducing the chromite ore to metallic ferrochromium is eliminated, which adversely affects both the content of Cr/sub 2/O/sub 3/ in the fused material, and also the commercial appearance of the resulting refractories. The authors developed a technology for preparing periclase-chromite refractories with chrommite-periclase constituents. The goods obtained possess good physicoceramic properties and a low content of silicites. The articles thus prepared were used to make the linings of the most critical parts of the converters which allowed an increase to be made in the duration of campaigns for the Kivset units of 1.5-2 times.

  7. Multimodal Plasmonics in Fused Colloidal Networks

    PubMed Central

    Teulle, Alexandre; Bosman, Michel; Girard, Christian; Gurunatha, Kargal L.; Li, Mei; Mann, Stephen; Dujardin, Erik

    2014-01-01

    Harnessing the optical properties of noble metals down to the nanometer-scale is a key step towards fast and low-dissipative information processing. At the 10-nm length scale, metal crystallinity and patterning as well as probing of surface plasmon (SP) properties must be controlled with a challenging high level of precision. Here, we demonstrate that ultimate lateral confinement and delocalization of SP modes are simultaneously achieved in extended self-assembled networks comprising linear chains of partially fused gold nanoparticles. The spectral and spatial distributions of the SP modes associated with the colloidal superstructures are evidenced by performing monochromated electron energy loss spectroscopy with a nanometer-sized electron probe. We prepare the metallic bead strings by electron beam-induced interparticle fusion of nanoparticle networks. The fused superstructures retain the native morphology and crystallinity but develop very low energy SP modes that are capable of supporting long range and spectrally tunable propagation in nanoscale waveguides. PMID:25344783

  8. Wear of Spur Gears Having a Dithering Motion and Lubricated with a Perfluorinated Polyether Grease

    NASA Technical Reports Server (NTRS)

    Krantz, Timothy; Oswald, Fred; Handschuh, Robert

    2007-01-01

    Gear contact surface wear is one of the important failure modes for gear systems. Dedicated experiments are required to enable precise evaluations of gear wear for a particular application. The application of interest for this study required evaluation of wear of gears lubricated with a grade 2 perfluorinated polyether grease and having a dithering (rotation reversal) motion. Experiments were conducted using spur gears made from AISI 9310 steel. Wear was measured using a profilometer at test intervals encompassing 10,000 to 80,000 cycles of dithering motion. The test load level was 1.1 GPa maximum Hertz contact stress at the pitch-line. The trend of total wear as a function of test cycles was linear, and the wear depth rate was approximately 1.2 nm maximum wear depth per gear dithering cycle. The observed wear rate was about 600 times greater than the wear rate for the same gears operated at high speed and lubricated with oil.

  9. Adsorption and hydraulic conductivity of landfill-leachate perfluorinated compounds in bentonite barrier mixtures.

    PubMed

    Li, Belinda; Li, Loretta Y; Grace, John R

    2015-06-01

    Perfluorinated compounds (PFCs) are leached in landfills from a wide range of domestic and industrial products. Sodium bentonite, a common barrier material, was contacted with water and landfill leachate spiked with PFCs in batch adsorption tests to measure PFC adsorption. Leaching cell tests were also conducted in which water, landfill leachate and PFC-spiked leachate permeated through compacted sand-bentonite mixtures. It was found that the PFCs did not bind substantially to the bentonite. Hydraulic conductivities were not appreciably affected by the PFCs, showing that bentonite liners are not affected for the range of concentrations tested. The sand-bentonite mixture partially retained the PFCs, indicating limited effectiveness in containing PFC within landfills.

  10. Removal of perfluorinated compounds in wastewater treatment plant effluents by electrochemical oxidation.

    PubMed

    Zhang, Chunhui; Wang, Liangliang; Li, Juan; Su, Peidong; Peng, Chen

    2015-01-01

    The presence of perfluorinated compounds (PFCs) in the effluents of a wastewater treatment plant (WWTP) in Beijing was investigated in the current study. Perfluorooctanoate acid and perfluorooctane sulfonate were the predominant PFCs in wastewater, accounting for 19-27% and 18-31%, respectively. The concentrations of PFCs with long chains were much lower than those PFCs with short chains (≤C8). An electrochemical oxidation reactor was employed for advanced treatment of PFCs in WWTP effluents using stainless steel plates as anode and cathode electrodes. It was concluded that the removal efficiency of PFCs was improved accordingly with the increasing applied current density. The removal efficiencies of target PFCs ranged from 23.53 to 51.79% with a reaction time of 30 minutes, current density of 20 mA/cm(2), electrode plate distance of 1.0 cm and electrode plate amounts of five pairs.

  11. Perfluorinated polymer electrolytes hybridized with in situ grown titania quasi-networks.

    PubMed

    Patil, Yatin; Sambandam, Satheesh; Ramani, Vijay; Mauritz, Kenneth

    2013-01-01

    Perfluorinated Nafion membranes, neutralized to various extents, were hybridized with titania quasi-networks that were grown in situ via catalyzed sol-gel reactions of an titanium isopropoxide precursor. The formation of Ti-O-Ti groups within the ionomer was verified by FTIR-ATR spectroscopy. EDAX studies confirmed that the extent of propagation of titania quasi-networks into the bulk of the ionomer film increased with ionomer neutralization. Compared to the unmodified control membrane, the hybrid membranes exhibited superior dimensional stability, modulus, stress, and strain at break and gas barrier properties. All hybrid membranes exhibited superior resistance to degradation when subjected to an accelerated stress test in an operating fuel cell environment, as a resultant of the better dimensional stability and gas barrier properties induced through addition of the inorganic titania phase.

  12. The Effects of Confinement of Thin Spin Cast Films of Perfluorinated Ionomers

    NASA Astrophysics Data System (ADS)

    Perahia, Dvora; Hill, Teresa

    2003-03-01

    The surface structure and its response to annealing upon confinement of spin coated perfluorinated ion-containing polymer have been studied by atomic force microscopy, X-ray scattering, and non-polarized neutron reflectometry. Similar to self- assembled films, the spin coated ionomers form structured films consisting of bundles of micelles. In contrast to self-assembled films, in spin coated ones hexagonal arrangements of the basic structural units are observed. Films with thickness ranging from 350 Å to 1050 Å have been investigated as a function of annealing time above the glass transition temperature of the fluorinated backbones. The films remain intact and do not de-wet when heated above the glass transition temperature of the polymer, contrary to what has been observed in thin di-block copolymers. The film thickness affects the ability of the ionomer to rearrange and releases constraints imposed by the spin coating procedure.

  13. [Distribution of perfluorinated compounds in surface water of Shenzhen reservoir groups].

    PubMed

    Wang, Xin-Xuan; Zhang, Hong; He, Long; Shen, Jin-Can; Chai, Zhi-Fang; Yang, Bo; Wang, Yan-Ping

    2014-06-01

    In order to study the concentrations of 14 perfluorinated compounds (PFCs) in 25 surface water samples collected from 12 Shenzhen reservoirs in November of 2012 and January of 2013, high performance liquid chromatography-tandem mass spectrometry was combined with solid phase extraction enrichment in this research. The results indicated that perfluorohexane sulfonate and long-chain (C > or = 11) PFCs were below the detection limit in all samples and perfluorooctane acid was the primary species. No significant difference in concentration was found between samples from the center of the reservoir and the outlet. Heavy precipitations diluted PFCs concentrations in surface water, but also led to PFOA input. PFCs concentrations in surface water of the reservoir were mainly affected by water inlet, source environment and geography. Although the water temperature had positive correlations with sigma PFCs concentration, the influence of heavy precipitations was stronger than that of water temperature.

  14. QENS investigation of proton confined motions in hydrated perfluorinated sulfonic membranes and self-assembled surfactants

    NASA Astrophysics Data System (ADS)

    Berrod, Quentin; Lyonnard, Sandrine; Guillermo, Armel; Ollivier, Jacques; Frick, Bernhard; Gébel, Gérard

    2015-01-01

    We report on QuasiElastic Neutron Scattering (QENS) investigations of the dynamics of protons and water molecules confined in nanostructured perfluorinated sulfonic acid (PFSA) materials, namely a commercial Aquivion membrane and the perfluorooctane sulfonic acid (PFOS) surfactant. The former is used as electrolyte in low-temperature fuel cells, while the latter forms mesomorphous self-assembled phases in water. The dynamics was investigated as a function of the hydration level, in a wide time range by combining time-of-flight and backscattering incoherent QENS experiments. Analysis of the quasielastic broadening revealed for both systems the existence of localized translational diffusive motions, fast rotational motions and slow hopping of protons in the vicinity of the sulfonic charges. The characteristic times and diffusion coefficients have been found to exhibit a very similar behaviour in both membrane and surfactant structures. Our study provides a comprehensive picture of the proton motion mechanisms and the dynamics of confined water in model and real PFSA nanostructures.

  15. Perfluorinated compounds in the Antarctic region: ocean circulation provides prolonged protection from distant sources.

    PubMed

    Bengtson Nash, Susan; Rintoul, Stephen R; Kawaguchi, So; Staniland, Iain; van den Hoff, John; Tierney, Megan; Bossi, Rossana

    2010-09-01

    In order to investigate the extent to which Perfluorinated Contaminants (PFCs) have permeated the Southern Ocean food web to date, a range of Antarctic, sub-Antarctic and Antarctic-migratory biota were analysed for key ionic PFCs. Based upon the geographical distribution pattern and ecology of biota with detectable vs. non-detectable PFC burdens, an evaluation of the potential contributory roles of alternative system input pathways is made. Our analytical findings, together with previous reports, reveal only the occasional occurrence of PFCs in migratory biota and vertebrate predators with foraging ranges extending into or north of the Antarctic Circumpolar Current (ACC). Geographical contamination patterns observed correspond most strongly with those expected from delivery via hydrospheric transport as governed by the unique oceanographic features of the Southern Ocean. We suggest that hydrospheric transport will form a slow, but primary, input pathway of PFCs to the Antarctic region.

  16. Degradation of Perfluorinated Ether Lubricants on Pure Aluminum Surfaces: Semiempirical Quantum Chemical Modeling

    NASA Technical Reports Server (NTRS)

    Slaby, Scott M.; Ewing, David W.; Zehe, Michael J.

    1997-01-01

    The AM1 semiempirical quantum chemical method was used to model the interaction of perfluoroethers with aluminum surfaces. Perfluorodimethoxymethane and perfluorodimethyl ether were studied interacting with aluminum surfaces, which were modeled by a five-atom cluster and a nine-atom cluster. Interactions were studied for edge (high index) sites and top (low index) sites of the clusters. Both dissociative binding and nondissociative binding were found, with dissociative binding being stronger. The two different ethers bound and dissociated on the clusters in different ways: perfluorodimethoxymethane through its oxygen atoms, but perfluorodimethyl ether through its fluorine atoms. The acetal linkage of perfluorodimeth-oxymethane was the key structural feature of this molecule in its binding and dissociation on the aluminum surface models. The high-index sites of the clusters caused the dissociation of both ethers. These results are consistent with the experimental observation that perfluorinated ethers decompose in contact with sputtered aluminum surfaces.

  17. Demonstrating Earth connections and fuses working together

    NASA Astrophysics Data System (ADS)

    Harrison, Mark

    2017-03-01

    Earth wires and fuses work together in UK mains circuits to keep users safe from electric shocks and are taught in many school contexts. The subject can be quite abstract and difficult for pupils to grasp, and a simple but visually clear and direct demonstration is described which would be easy for most physics departments to build and which can make the concepts much more immediately understandable.

  18. Thermal fuse for high-temperature batteries

    DOEpatents

    Jungst, Rudolph G.; Armijo, James R.; Frear, Darrel R.

    2000-01-01

    A thermal fuse, preferably for a high-temperature battery, comprising leads and a body therebetween having a melting point between approximately 400.degree. C. and 500.degree. C. The body is preferably an alloy of Ag--Mg, Ag--Sb, Al--Ge, Au--In, Bi--Te, Cd--Sb, Cu--Mg, In--Sb, Mg--Pb, Pb--Pd, Sb--Zn, Sn--Te, or Mg--Al.

  19. 49 CFR 173.184 - Highway or rail fusee.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SHIPMENTS AND PACKAGINGS Non-bulk Packaging for Hazardous Materials Other Than Class 1 and Class 7 § 173.184 Highway or rail fusee. (a) A fusee is a device designed to burn at a controlled rate and to produce visual...), plywood (1D) or fiber (1G) drums. If the fusees are equipped with spikes packagings must have...

  20. Perfluorinated alkyl acids in the plasma of South African crocodiles (Crocodylus niloticus).

    PubMed

    Christie, Ian; Reiner, Jessica L; Bowden, John A; Botha, Hannes; Cantu, Theresa M; Govender, Danny; Guillette, Matthew P; Lowers, Russell H; Luus-Powell, Wilmien J; Pienaar, Danie; Smit, Willem J; Guillette, Louis J

    2016-07-01

    Perfluorinated alkyl acids (PFAAs) are environmental contaminants that have been used in many products for over 50 years. Interest and concern has grown since 2000 on the widespread presence of PFAAs, when it was discovered that PFAAs were present in wildlife samples around the northern hemisphere. Since then, several studies have reported PFAAs in wildlife from many locations, including the remote regions of Antarctica and the Arctic. Although there are a multitude of studies, few have reported PFAA concentrations in reptiles and wildlife in the Southern Hemisphere. This study investigated the presence of PFAAs in the plasma of Nile crocodiles (Crocodylus niloticus) from South Africa. Crocodiles were captured from five sites in and around the Kruger National Park, South Africa, and plasma samples examined for PFAAs. Perfluorooctane sulfonate (PFOS) was the most frequent PFAA detected; with median values of 13.5 ng/g wet mass in crocodiles. In addition to PFOS, long chain perfluorinated carboxylic acids were also detected. Correlations between total length and PFAA load were investigated, as were differences in PFAA accumulation between sexes. No correlations were seen between crocodile size, nor were there sex-related differences. Spatial differences were examined and significant differences were observed in samples collected from the different sites (p < 0.05). Flag Boshielo Dam had the highest PFOS measurements, with a median concentration of 50.3 ng/g wet mass, when compared to the other sites (median concentrations at other sites below 14.0 ng/g wet mass). This suggests a point source of PFOS in this area.

  1. Mechanism of cytotoxic action of perfluorinated acids. III. Disturbance in Ca{sup 2+} homeostasis

    SciTech Connect

    Kleszczynski, Konrad; Skladanowski, Andrzej C.

    2011-03-01

    The global distribution of perfluorinated acids (PFAs) in industry and in household is well known. Their increasing environmental occurrence and biomagnification in the living organisms have drawn growing interests in efforts to describe precisely the mechanisms of action in vitro and in vivo. Our previous investigations widely described lipophilicity-dependent cytotoxicity of PFAs as well as the effect of perfluorination of carbon chain on depolarization of plasma membrane potential, acidification or mitochondrial dysfunctions. In this study we presented in dose- and time-dependent manner the impact of PFAs on calcium homeostasis in HCT116 cells. Comparative analysis of cytosolic [Ca{sup 2+}]{sub c} and mitochondrial calcium [Ca{sup 2+}]{sub m} carried out by flow cytometry revealed distinct uptake of calcium into mitochondria in correlation to increasing lipophilicity of PFAs. Massive accumulation of [Ca{sup 2+}]{sub m} was not accompanied by equivalent loss of [Ca{sup 2+}]{sub c}. Indeed, moderate changes of [Ca{sup 2+}]{sub c} were observed after incubation with 400 {mu}M PFDoDA reaching 29.83% and 49.17% decrease at 4th and 72nd hour, respectively. At the same time, mitochondrial calcium uptake increased from 2- to more than 4-fold comparing with non-treated cells. Incubation with non-fluorinated decanoic acid (DA) did not cause any changes in calcium homeostasis. Presented data show that PFAs-induced perturbations in calcium distribution seem to be a missing link related to mitochondria dysfunction playing a crucial role in determination of apoptotic cell death. Complete scheme for the mechanism of cytotoxic action of PFAs has been included.

  2. Metabolically inert perfluorinated fatty acids directly activate uncoupling protein 1 in brown-fat mitochondria.

    PubMed

    Shabalina, Irina G; Kalinovich, Anastasia V; Cannon, Barbara; Nedergaard, Jan

    2016-05-01

    The metabolically inert perfluorinated fatty acids perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) can display fatty acid-like activity in biological systems. The uncoupling protein 1 (UCP1) in brown adipose tissue is physiologically (re)activated by fatty acids, including octanoate. This leads to bioenergetically uncoupled energy dissipation (heat production, thermogenesis). We have examined here the possibility that PFOA/PFOS can directly (re)activate UCP1 in isolated mouse brown-fat mitochondria. In wild-type brown-fat mitochondria, PFOS and PFOA overcame GDP-inhibited thermogenesis, leading to increased oxygen consumption and dissipated membrane potential. The absence of this effect in brown-fat mitochondria from UCP1-ablated mice indicated that it occurred through activation of UCP1. A competitive type of inhibition by increased GDP concentrations indicated interaction with the same mechanistic site as that utilized by fatty acids. No effect was observed in heart mitochondria, i.e., in mitochondria without UCP1. The stimulatory effect of PFOA/PFOS was not secondary to non-specific mitochondrial membrane permeabilization or to ROS production. Thus, metabolic effects of perfluorinated fatty acids could include direct brown adipose tissue (UCP1) activation. The possibility that this may lead to unwarranted extra heat production and thus extra utilization of food resources, leading to decreased fitness in mammalian wildlife, is discussed, as well as possible negative effects in humans. However, a possibility to utilize PFOA-/PFOS-like substances for activating UCP1 therapeutically in obesity-prone humans may also be envisaged.

  3. Antioxidant Activity of Novel Fused Heterocyclic Compounds Derived from Tetrahydropyrimidine Derivative.

    PubMed

    Salem, Marwa Sayed; Farhat, Mahmoud; Errayes, Asma Omar; Madkour, Hassan Mohamed Fawzy

    2015-01-01

    6-(Benzo[d][1,3]dioxol-5-yl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile has been utilized for synthesis of the fused heterocyclic compounds namely thiazolopyrimidines, tetrazolopyrimidine, pyrimidoquinazoline, pyrimidothiazolopyrimidine, pyrimidothiazolotriazine and pyrrolothiazolopyrimidine derivatives. The newly synthesized compounds were characterized by IR, (1)H-NMR, (13)C-NMR, and mass spectral data. Antioxidant activities of all synthesized compounds were investigated.

  4. Outbursts In Symbiotic Binaries (FUSE 2000)

    NASA Technical Reports Server (NTRS)

    Kenyon, Scott J.; Sonneborn, George (Technical Monitor)

    2002-01-01

    During the past year, we made good progress on analysis of FUSE observations of the symbiotic binary Z And. For background, Z And is a binary system composed of a red giant and a hot component of unknown status. The orbital period is roughly 750 days. The hot component undergoes large-scale eruptions every 10-20 yr. An outburst began several years ago, triggering this FUSE opportunity. First, we obtained an excellent set of ground-based optical data in support, of the FUSE observations. We used FAST, a high throughput low resolution spectrograph on the 1.5-m telescope at Mt. Hopkins, Arizona. A 300 g/ mm grating blazed at 4750 A, a 3 in. slit, and a thinned Loral 512 x 2688 CCD gave us spectra covering 3800-7500 A at a resolution of 6 A. The wavelength solution for each spectrum has a probable error of +/- 0.5 A or better. Most of the resulting spectra have moderate signal-to-noise, S/.N approx. greater than 30 per pixel. The time coverage for these spectra is excellent. Typically, we acquired spectra every 1-2 nights during dark runs at Mt. Hopkins. These data cover most of the rise and all of the decline of the recent outburst. The spectra show a wealth of emission lines, including H I, He I, He II, [Fe V11], and the Raman scattering bands at 6830 A and 7088 A. The Raman bands and other high ionization features vary considerably throughout the outburst. These features will enable us to correlate variations in the FUSE spectra with variations in the optical spectra. Second, we began an analysis of FUSE spectra of Z And. We have carefully examined the spectra, identifying real features and defects. We have identified and measured fluxes for all strong emission lines, including the O VI doublet at 1032 A and 1038 A. These and several other strong emission lines display pronounced P Cygni absorption components indicative of outgrowing gas. We will attempt to correlate these velocities with similar profiles observed on optical spectra. The line velocities - together

  5. FL V1.3

    SciTech Connect

    Rothganger, Frederick

    2009-08-03

    A library of utility classes for computer vision. Contains implementations of various well-known image processing techniques, such as interest point operators and region descriptors. Includes interfaces to various libraries for image and video I/O, as well as an interface to LAPACK/BLAS. FL was developed at the University of Illinois, Urbana-Champaign (UIUC) and released under an open source license. Version 1.2 was a maintenance release provided by SNL under the LGPL license. Version 1.3 is a maintenance release, containing the following changes: - Improved image format handling. Now handles strided and planar memory layouts and a wider range of pixel formats. - Improved image file I/O, including better support for metadata, a wider range of stored pixel types, and a couple of new file formats. - Improvements to DOG and SIFT, and efficiency improvements in low-level convolution. - Improvements to networking, including a generic TCP listener. - Various improvements to numerical processing. The HISTORY file included in the distribution contains a more detailed description of the changes.

  6. Perfluorinated carbon-chain copolymers with functional groups and cation exchange membranes based on them: synthesis, structure and properties

    NASA Astrophysics Data System (ADS)

    Kirsh, Yu E.; Smirnov, S. A.; Popkov, Yu M.; Timashev, Sergei F.

    1990-06-01

    The review is devoted to perfluorinated polymers with sulphonic and carboxylic acid groups and to cation exchange membranes based on them. The synthesis is described of copolymers of tetrafluoroethylene with perfluorovinyl ethers containing functional groups by radical copolymerisation in an organic medium and in aqueous emulsions. Special features of the copolymerisation and approaches to obtaining copolymers with set characteristics are discussed. Data are presented on the structure and physicochemical properties of the polymeric films. Attempts to form membranes from the polymers obtained, the means of strengthening them and methods for chemical modification are described. Data are correlated on the influence of structure and polymer composition and the nature of the functional groups on the electrochemical characteristics of membranes. Special features of the functioning of perfluorinated membranes in the process for making chlorine and alkali by the electrolysis of sodium chloride solution are considered. The bibliography has 104 references.

  7. Organocatalytic sequential hetero-Diels-Alder and Friedel-Crafts reaction: constructions of fused heterocycles with scaffold diversity.

    PubMed

    Zhou, Si-Li; Li, Jun-Long; Dong, Lin; Chen, Ying-Chun

    2011-11-04

    A highly enantioselective aza-Diels-Alder and Friedel-Crafts reaction sequence of N-sulfonyl-1-aza-1,3-butadienes and aliphatic aldehydes tethered to an arene motif has been developed, affording the fused chiral piperidine frameworks with a versatile scaffold diversity. A similar strategy has been applied for the construction of complex chiral tetrahydroquinoxaline structures.

  8. FUSE Observations of Comet C/2001 Q4 (NEAT)

    NASA Astrophysics Data System (ADS)

    Feldman, P. D.; Weaver, H. A.; Christian, D.; Combi, M. R.; Krasnopolsky, V.; Lisse, C. M.; Mumma, M. J.; Shemansky, D. E.; Stern, S. A.

    2004-11-01

    We report observations of comet C/2001 Q4 (NEAT) with the Far Ultraviolet Spectroscopic Explorer (FUSE) beginning 00:40 UT on 2004 April 24. This was the first moving target observation made by FUSE since the failure of two reaction wheels in December 2001. Spectra were obtained in the 905--1180 Å range at 0.3 Å spectral resolution using the 30'' × 30'' aperture and closely resemble the spectra of three comets observed in 2001 and reported previously. The principal features are the (0,0) bands of the CO Birge-Hopfield systems, atomic lines of \\ion{O}{1} and \\ion{H}{1}, and three lines of the H2 Lyman pumped by solar Lyman-β fluorescence. The CO C - X (0,0) band showed a nearly sinusoidal variation over the 27 hr observation interval with a period of 17.0 hr and a peak to minimum ratio of 1.56. The derived average CO production rate is Q(CO) = 8 × 1027 molecules s-1 which is about 4% that of H2O based on concurrent HST/STIS observations of OH emission. As in the previous observations, only upper limits are found for emission from \\ion{Ar}{1} and N2. A relatively strong feature near 1031.8 Å is most likely the H2 Werner (1,1) Q3 line pumped by solar \\ion{O}{6} and \\ion{N}{3}, as the corresponding lines in the (1,3) and (1,4) bands are also present. There may be evidence for weak \\ion{O}{6} emission at 1031.9 Å, in the wing of the H2 line, and at 1037.6 Å. The roughly two dozen other emissions that were not identified in the earlier spectra are also present in C/2001 Q4 at comparable strength to those in comet C/2001 A2 (LINEAR). As C/2001 A2 had a comparable water production rate to that of C/2001 Q4 at the time of observation, the source(s) of these emissions may be ubiquitous in comets. This work is based on data obtained by the NASA-CNES-CSA FUSE mission operated by The Johns Hopkins University. Financial support was partly provided by NASA contract NAS5-32985.

  9. Perfluorinated chemicals: Differential toxicity, inhibition of aromatase activity and alteration of cellular lipids in human placental cells

    SciTech Connect

    Gorrochategui, Eva; Pérez-Albaladejo, Elisabet; Casas, Josefina; Lacorte, Sílvia; Porte, Cinta

    2014-06-01

    The cytotoxicity of eight perfluorinated chemicals (PFCs), namely, perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorododecanoic acid (PFDoA), perfluorobutanesulfonate (PFBS), perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) was assessed in the human placental choriocarcinoma cell line JEG-3. Only the long chain PFCs – PFOS, PFDoA, PFNA, PFOA – showed significant cytotoxicity in JEG-3 cells with EC50 values in the range of 107 to 647 μM. The observed cytotoxicity was to some extent related to a higher uptake of the longer chain PFCs by cells (PFDoA > PFOS ≫ PFNA > PFOA > PFHxA). Moreover, this work evidences a high potential of PFOS, PFOA and PFBS to act as aromatase inhibitors in placental cells with IC50s in the range of 57–80 μM, the inhibitory effect of PFBS being particularly important despite the rather low uptake of the compound by cells. Finally, exposure of JEG-3 cells to a mixture of the eight PFCs (0.6 μM each) led to a relative increase (up to 3.4-fold) of several lipid classes, including phosphatidylcholines (PCs), plasmalogen PC and lyso plasmalogen PC, which suggests an interference of PFCs with membrane lipids. Overall, this work highlights the ability of the PFC mixture to alter cellular lipid pattern at concentrations well below those that generate toxicity, and the potential of the short chain PFBS, often considered a safe substitute of PFOS, to significantly inhibit aromatase activity in placental cells. - Highlights: • Eight perfluorinated chemicals of different chain lengths have been selected. • Long chain ones – PFOS, PFDoA, PFNA, PFOA – were cytotoxic in placenta cells. • The uptake of long chain perfluorinated chemicals by cells was comparatively higher. • PFOS, PFOA and the short chain PFBS significantly inhibited aromatase activity. • A mixture of perfluorinated chemicals significantly altered placenta cell

  10. Determination of perfluorinated compounds in fish fillet homogenates: method validation and application to fillet homogenates from the Mississippi River.

    PubMed

    Malinsky, Michelle Duval; Jacoby, Cliffton B; Reagen, William K

    2011-01-10

    We report herein a simple protein precipitation extraction-liquid chromatography tandem mass spectrometry (LC/MS/MS) method, validation, and application for the analysis of perfluorinated carboxylic acids (C7-C12), perfluorinated sulfonic acids (C4, C6, and C8), and perfluorooctane sulfonamide (FOSA) in fish fillet tissue. The method combines a rapid homogenization and protein precipitation tissue extraction procedure using stable-isotope internal standard (IS) calibration. Method validation in bluegill (Lepomis macrochirus) fillet tissue evaluated the following: (1) method accuracy and precision in both extracted matrix-matched calibration and solvent (unextracted) calibration, (2) quantitation of mixed branched and linear isomers of perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) with linear isomer calibration, (3) quantitation of low level (ppb) perfluorinated compounds (PFCs) in the presence of high level (ppm) PFOS, and (4) specificity from matrix interferences. Both calibration techniques produced method accuracy of at least 100±13% with a precision (%RSD) ≤18% for all target analytes. Method accuracy and precision results for fillet samples from nine different fish species taken from the Mississippi River in 2008 and 2009 are also presented.

  11. Optical Performance Modeling of FUSE Telescope Mirror

    NASA Technical Reports Server (NTRS)

    Saha, Timo T.; Ohl, Raymond G.; Friedman, Scott D.; Moos, H. Warren

    2000-01-01

    We describe the Metrology Data Processor (METDAT), the Optical Surface Analysis Code (OSAC), and their application to the image evaluation of the Far Ultraviolet Spectroscopic Explorer (FUSE) mirrors. The FUSE instrument - designed and developed by the Johns Hopkins University and launched in June 1999 is an astrophysics satellite which provides high resolution spectra (lambda/Delta(lambda) = 20,000 - 25,000) in the wavelength region from 90.5 to 118.7 nm The FUSE instrument is comprised of four co-aligned, normal incidence, off-axis parabolic mirrors, four Rowland circle spectrograph channels with holographic gratings, and delay line microchannel plate detectors. The OSAC code provides a comprehensive analysis of optical system performance, including the effects of optical surface misalignments, low spatial frequency deformations described by discrete polynomial terms, mid- and high-spatial frequency deformations (surface roughness), and diffraction due to the finite size of the aperture. Both normal incidence (traditionally infrared, visible, and near ultraviolet mirror systems) and grazing incidence (x-ray mirror systems) systems can be analyzed. The code also properly accounts for reflectance losses on the mirror surfaces. Low frequency surface errors are described in OSAC by using Zernike polynomials for normal incidence mirrors and Legendre-Fourier polynomials for grazing incidence mirrors. The scatter analysis of the mirror is based on scalar scatter theory. The program accepts simple autocovariance (ACV) function models or power spectral density (PSD) models derived from mirror surface metrology data as input to the scatter calculation. The end product of the program is a user-defined pixel array containing the system Point Spread Function (PSF). The METDAT routine is used in conjunction with the OSAC program. This code reads in laboratory metrology data in a normalized format. The code then fits the data using Zernike polynomials for normal incidence

  12. Quartz/fused silica chip carriers

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The primary objective of this research and development effort was to develop monolithic microwave integrated circuit (MMIC) packaging which will operate efficiently at millimeter-wave frequencies. The packages incorporated fused silica as the substrate material which was selected due to its favorable electrical properties and potential performance improvement over more conventional materials for Ka-band operation. The first step towards meeting this objective is to develop a package that meets standard mechanical and thermal requirements using fused silica and to be compatible with semiconductor devices operating up to at least 44 GHz. The second step is to modify the package design and add multilayer and multicavity capacity to allow for application specific integrated circuits (ASIC's) to control multiple phase shifters. The final step is to adapt the package design to a phased array module with integral radiating elements. The first task was a continuation of the SBIR Phase 1 work. Phase 1 identified fused silica as a viable substrate material by demonstrating various plating, machining, and adhesion properties. In Phase 2 Task 1, a package was designed and fabricated to validate these findings. Task 2 was to take the next step in packaging and fabricate a multilayer, multichip module (MCM). This package is the predecessor to the phased array module and demonstrates the ability to via fill, circuit print, laminate, and to form vertical interconnects. The final task was to build a phased array module. The radiating elements were to be incorporated into the package instead of connecting to it with wire or ribbon bonds.

  13. Synthesis of novel fused quinazolinone derivatives.

    PubMed

    Mahdavi, Mohammad; Lotfi, Vahid; Saeedi, Mina; Kianmehr, Ebrahim; Shafiee, Abbas

    2016-08-01

    A four-step synthetic route was developed for the synthesis of novel fused quinazolinones, quinazolino[3,4-a]quinazolinones, and isoinodolo[2,1-a]quinazolino[1,2-c]quinazolineones. Reaction of isatoic anhydride and different amines gave various 2-aminobenzamides. Then, reaction of 2-aminobenzamides with 2-nitrobenzaldehyde followed by the reduction of nitro group afforded 2-(2-aminophenyl)-3-aryl-2,3-dihydroquinazolin-4(1H)-one derivatives. Finally, reaction of the latter compounds with aromatic aldehydes or 2-formylbenzoic acid led to the formation of the corresponding products.

  14. Fused silica mirror development for SIRTF

    NASA Technical Reports Server (NTRS)

    Barnes, W. P., Jr.

    1983-01-01

    An advanced design, lightweight, fuse-quartz mirror of sandwich construction was evaluated for optical figure performance at cryogenic temperatures. A low temperature shroud was constructed with an integral mirror mount and interface to a cryostat for use in a vacuum chamber. The mirror was tested to 13 K. Cryogenic distortion of the mirror was measured interferometrically. Separate interferometry of the chamber window during the test permitted subtraction of the small window distortions from the data. Results indicate that the imaging performance of helium cooled, infrared telescopes will be improved using this type of mirror without correction of cryogenic distortion of the primary mirror.

  15. Evolutionary explosions and the phylogenetic fuse.

    PubMed

    Cooper, A; Fortey, R

    1998-04-01

    A literal reading of the fossil record indicates that the early Cambrian (c. 545 million years ago) and early Tertiary (c. 65 million years ago) were characterized by enormously accelerated periods of morphological evolution marking the appearance of the animal phyla, and modern bird and placental mammal orders, respectively. Recently, the evidence for these evolutionary `explosions' has been questioned by cladistic and biogeographic studies which reveal that periods of diversification before these events are missing from the fossil record. Furthermore, molecular evidence indicates that prolonged periods of evolutionary innovation and cladogenesis lit the fuse long before the `explosions' apparent in the fossil record.

  16. Medicinal Chemistry Perspective of Fused Isoxazole Derivatives.

    PubMed

    Barmade, Mahesh A; Murumkar, Prashant R; Sharma, Mayank Kumar; Yadav, Mange Ram

    2016-01-01

    Nitrogen containing heterocyclic rings with an oxygen atom is considered as one of the best combination in medicinal chemistry due to their diversified biological activities. Isoxazole, a five membered heterocyclic azole ring is found in naturally occuring ibetonic acid along with some of the marketed drugs such as valdecoxib, flucloxacillin, cloxacillin, dicloxacillin, and danazol. It is also significant for showing antipsychotic activity in risperidone and anticonvulsant activity in zonisamide, the marketed drugs. This review article covers research articles reported till date covering biological activity along with SAR of fused isoxazole derivatives.

  17. FUSE Observations of K--M Stars

    NASA Astrophysics Data System (ADS)

    Ake, T. B.; Dupree, A. K.; Linsky, J. L.; Harper, G. M.; Young, P. R.

    2000-12-01

    As part of the FUSE PI program, a representative sample of cool stars is being surveyed in the LWRS (30 x 30 arcsec) aperture. We report on recent observations of three late-type stars, AU Mic (HD 197481, M0 Ve), β Gem (HD 62509, K0 IIIb), and α Ori (HD 39801, M1-2 Ia--Iab). AU Mic and β Gem show strong emission lines of O VI 1032/1037 and C III 977/1176 and weaker lines of C II, N II, N III, S IV, Si III, Si IV, and perhaps Fe III. AU Mic has evidence of He II and S III emission, and β Gem shows S I emission. Differences are seen in line ratios and line profiles between these stars. In α Ori, these features are very weak or non-existent, and Fe II fluorescent lines in the 1100-1150 Å region, pumped by H I Lyman α , are present. Several emission lines are still unidentified in all spectra. Prospects for future cool star observations will be discussed. This work is based on data obtained for the Guaranteed Time Team by the NASA-CNES-CSA FUSE mission operated by the Johns Hopkins University. Financial support to U. S. participants has been provided by NASA contract NAS5-32985.

  18. Fused Reality for Enhanced Flight Test Capabilities

    NASA Technical Reports Server (NTRS)

    Bachelder, Ed; Klyde, David

    2011-01-01

    The feasibility of using Fused Reality-based simulation technology to enhance flight test capabilities has been investigated. In terms of relevancy to piloted evaluation, there remains no substitute for actual flight tests, even when considering the fidelity and effectiveness of modern ground-based simulators. In addition to real-world cueing (vestibular, visual, aural, environmental, etc.), flight tests provide subtle but key intangibles that cannot be duplicated in a ground-based simulator. There is, however, a cost to be paid for the benefits of flight in terms of budget, mission complexity, and safety, including the need for ground and control-room personnel, additional aircraft, etc. A Fused Reality(tm) (FR) Flight system was developed that allows a virtual environment to be integrated with the test aircraft so that tasks such as aerial refueling, formation flying, or approach and landing can be accomplished without additional aircraft resources or the risk of operating in close proximity to the ground or other aircraft. Furthermore, the dynamic motions of the simulated objects can be directly correlated with the responses of the test aircraft. The FR Flight system will allow real-time observation of, and manual interaction with, the cockpit environment that serves as a frame for the virtual out-the-window scene.

  19. Fusing Symbolic and Numerical Diagnostic Computations

    NASA Technical Reports Server (NTRS)

    James, Mark

    2007-01-01

    X-2000 Anomaly Detection Language denotes a developmental computing language, and the software that establishes and utilizes the language, for fusing two diagnostic computer programs, one implementing a numerical analysis method, the other implementing a symbolic analysis method into a unified event-based decision analysis software system for realtime detection of events (e.g., failures) in a spacecraft, aircraft, or other complex engineering system. The numerical analysis method is performed by beacon-based exception analysis for multi-missions (BEAMs), which has been discussed in several previous NASA Tech Briefs articles. The symbolic analysis method is, more specifically, an artificial-intelligence method of the knowledge-based, inference engine type, and its implementation is exemplified by the Spacecraft Health Inference Engine (SHINE) software. The goal in developing the capability to fuse numerical and symbolic diagnostic components is to increase the depth of analysis beyond that previously attainable, thereby increasing the degree of confidence in the computed results. In practical terms, the sought improvement is to enable detection of all or most events, with no or few false alarms.

  20. Spectral fusing Gabor domain optical coherence microscopy.

    PubMed

    Meemon, Panomsak; Widjaja, Joewono; Rolland, Jannick P

    2016-02-01

    Gabor domain optical coherence microscopy (GD-OCM) is one of many variations of optical coherence tomography (OCT) techniques that aims for invariant high resolution across a 3D field of view by utilizing the ability to dynamically refocus the imaging optics in the sample arm. GD-OCM acquires multiple cross-sectional images at different focus positions of the objective lens, and then fuses them to obtain an invariant high-resolution 3D image of the sample, which comes with the intrinsic drawback of a longer processing time as compared to conventional Fourier domain OCT. Here, we report on an alternative Gabor fusing algorithm, the spectral-fusion technique, which directly processes each acquired spectrum and combines them prior to the Fourier transformation to obtain a depth profile. The implementation of the spectral-fusion algorithm is presented and its performance is compared to that of the prior GD-OCM spatial-fusion approach. The spectral-fusion approach shows twice the speed of the spatial-fusion approach for a spectrum size of less than 2000 point sampling, which is a commonly used spectrum size in OCT imaging, including GD-OCM.

  1. Analysis of perfluorinated carboxylic acids in soils II: optimization of chromatography and extraction.

    PubMed

    Washington, John W; Henderson, W Matthew; Ellington, J Jackson; Jenkins, Thomas M; Evans, John J

    2008-02-15

    With the objective of detecting and quantitating low concentrations of perfluorinated carboxylic acids (PFCAs), including perfluorooctanoic acid (PFOA), in soils, we compared the analytical suitability of liquid chromatography columns containing three different stationary phases, two different liquid chromatography-tandem mass spectrometry (LC/MS/MS) systems, and eight combinations of sample-extract pretreatments, extractions and cleanups on three test soils. For the columns and systems we tested, we achieved the greatest analytical sensitivity for PFCAs using a column with a C(18) stationary phase in a Waters LC/MS/MS. In this system we achieved an instrument detection limit for PFOA of 270 ag/microL, equating to about 14 fg of PFOA on-column. While an elementary acetonitrile/water extraction of soils recovers PFCAs effectively, natural soil organic matter also dissolved in the extracts commonly imparts significant noise that appears as broad, multi-nodal, asymmetric peaks that coelute with several PFCAs. The intensity and elution profile of this noise is highly variable among soils and it challenges detection of low concentrations of PFCAs by decreasing the signal-to-noise contrast. In an effort to decrease this background noise, we investigated several methods of pretreatment, extraction and cleanup, in a variety of combinations, that used alkaline and unbuffered water, acetonitrile, tetrabutylammonium hydrogen sulfate, methyl-tert-butyl ether, dispersed activated carbon and solid-phase extraction. For the combined objectives of complete recovery and minimization of background noise, we have chosen: (1) alkaline pretreatment; (2) extraction with acetonitrile/water; (3) evaporation to dryness; (4) reconstitution with tetrabutylammonium-hydrogen-sulfate ion-pairing solution; (5) ion-pair extraction to methyl-tert-butyl ether; (6) evaporation to dryness; (7) reconstitution with 60/40 acetonitrile/water (v/v); and (8) analysis by LC/MS/MS. Using this method, we

  2. Perfluorinated compounds in surface waters and WWTPs in Shenyang, China: mass flows and source analysis.

    PubMed

    Sun, Hongwen; Li, Fasong; Zhang, Tao; Zhang, Xianzhong; He, Na; Song, Qi; Zhao, Lijie; Sun, Lina; Sun, Tieheng

    2011-10-01

    Concentrations of 10 perfluorinated chemicals (PFCs) were investigated in the Hun River (HR), four canals, ten lakes, and influents and effluents from four main municipal wastewater treatment plants (WWTPs) in Shenyang, China. Mass flows of four main PFCs were calculated to elucidate the contribution from different sections of the HR. Overall, perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (PFHxA) were the major PFCs in the HR, with ranges of 2.68-9.13 ng/L, and 2.12-11.3 ng/L, respectively, while perfluorooctane sulfonate (PFOS) was detected at lower levels, ranging from 0.40 to 3.32 ng/L. The PFC concentrations in the HR increased after the river passes through two cities (Shenyang and Fushun), indicating cities are an important contributor for PFCs. Mass flow analysis in the HR revealed that PFC mass flows from Fushun are 1.65-5.50 kg/year for C6-C8 perfluorinated acids (PFCAs) and 1.29 kg/year for PFOS, while Shenyang contributed 2.83-5.18 kg C6-C8 PFCAs/year, and 3.65 kg PFOS/year. The concentrations of PFCs in four urban canals were higher than those in the HR, with the maximum total PFCs of 240 ng/L. PFOA and PFOS showed different trends along these canals, suggesting different sources for the two PFCs. Total PFCs in ten lakes from Shenyang were at low levels, with the greatest concentration (56.2 ng/L) detected in a heavily industrialized area. The PFC levels in WWTP effluents were higher than those in surface waters with concentrations ranging from 18.4 to 41.1 ng/L for PFOA, and 1.69-3.85 ng/L for PFOS. Similar PFC profiles between effluents from WWTPs and urban surface waters were found. These results indicate that WWTPs are an important PFC source in surface water. Finally, we found that the composition profiles of PFCs in surface waters were similar to those in tap water, but not consistent with those in adult blood from Shenyang. The calculation on total daily intake of PFOS by adults from Shenyang showed that the contribution of

  3. Fate of perfluorinated carboxylates and sulfonates during snowmelt within an urban watershed.

    PubMed

    Meyer, Torsten; De Silva, Amila O; Spencer, Christine; Wania, Frank

    2011-10-01

    The transport dynamics of perfluorinated carboxylic acids and sulfonates during snowmelt in the highly urbanized Highland Creek watershed in Toronto, Canada was investigated by analyzing river water, bulk snow, and groundwater, sampled in February and March 2010, by means of liquid chromatography-tandem mass spectrometry. Perfluorohexanoate, perfluorooctanoate, and perfluorooctane sulfonate were dominant in river water, with concentrations of 4.0-14 ng·L(-1), 2.2-7.9 ng·L(-1), and 2.1-6.5 ng·L(-1), respectively. Relatively high levels of perfluorohexanoate may be related to the recent partial replacement in various consumer products of perfluorooctyl substances with shorter-chained perfluorinated compounds (PFCs). Highest PFC concentrations were found within the more urbanized part of the drainage area, suggestive of residential, industrial, and/or traffic-related sources. The riverine flux of PFCs increased during the snowmelt period, but only approximately one-fifth of the increased flux can be attributed to PFCs present in the snowpack, mostly because concentration in snow are generally quite low compared to those in river water. The remainder of the increased flux must be due to the mobilization of PFCs by the high flow conditions prevalent during snowmelt. Run-off behavior was clearly dependent on perfluoroalkyl chain length: Dilution with relatively clean snowmelt water caused a drop in the river water concentrations of short-chain PFCs at high flow during early melting. This prevented an early concentration peak of those water-soluble PFCs within the stream, as could have been expected in response to their early release from a melting snowpack. Instead, concentrations of particle-associated long-chain PFCs in creek water peaked early in the melt, presumably because high flow mobilized contaminated particles from impervious surfaces in the more urbanized areas of the watershed. The ability to enter the subsurface and deeper groundwater aquifers increased

  4. Rapid, Microwave Accelerated Synthesis of [1,2,4]Triazolo[3,4-b][1,3,4]oxadiazoles from 4-Acylamino-1,2,4-Triazoles.

    PubMed

    Breunig, Stesphanie L; Olson, Margaret E; Harki, Daniel A

    2016-09-07

    1,2,4-Triazoles and 1,3,4-oxadiazoles are prevalent moieties in pharmaceutical agents, yet fused [1,2,4]-triazolo[3,4-b][1,3,4]oxadiazoles are surprisingly under-represented for both synthesis and biological application. We report a rapid, two-step synthesis of [1,2,4]-triazolo[3,4-b][1,3,4]oxadiazoles from commercial 4-amino-1,2,4-triazoles that is highlighted by a microwave accelerated intramolecular cyclization to generate the fused ring system. Our efforts to optimize reaction conditions and elucidate reaction mechanism are also described.

  5. High performance liquid chromatography tandem mass spectrometry determination of perfluorinated acids in cow milk.

    PubMed

    Capriotti, Anna Laura; Cavaliere, Chiara; Cavazzini, Alberto; Foglia, Patrizia; Laganà, Aldo; Piovesana, Susy; Samperi, Roberto

    2013-12-06

    A new and sensitive liquid chromatography/electrospray-tandem mass spectrometric (LC/ESI-MS/MS) method for the determination of 12 perfluorinated compounds (PFCs) in cow milk is described. Milk samples were extracted with acetone and cleaned-up by a graphitized carbon black solid-phase extraction cartridge, optimizing the entire procedure by using a screening experimental design. LC/ESI-MS/MS was performed in negative ion mode using multiple reaction monitoring mode. The performance of the method was evaluated under the optimized conditions in terms of matrix effects, range of linearity, accuracy, and repeatability. For all compounds, linearity in matrix was observed in the range LOQ-10μgL(-1), and coefficients of determination R(2) ranged from 0.9982 to 0.9999. The analytical recoveries, relative to the isotopic internal standard, measured at 10 and 50ngL(-1) were in the range of 91-105%, with relative standard deviations below 6% and method detection limit, based on the blank value +3 times the standard deviation of the blank, ranged from 0.5 to 3ngL(-1). The final method developed was used to determine the concentration of PFCs in 15 retail milk samples. None of these compounds were detected in cow milk analyzed samples.

  6. Abatement of Perfluorinated Compounds Using Cylindrical Microwave Plasma Source at Low Pressure

    NASA Astrophysics Data System (ADS)

    Kim, Seong Bong; Park, S.; Park, Y.; Youn, S.; Yoo, S. J.

    2016-10-01

    Microwave plasma source with a cylindrical cavity has been proposed to abate the perfluorinated compounds (PFCs). This plasma source was designed to generate microwave plasma with the cylindrical shape and to be easily installed in existing exhaust line. The microwave frequency is 2.45 GHz and the operating pressure range is 0.1 Torr to 0.3 Torr. The plasma characteristic of the cylindrical microwave plasma source was measured using the optical spectrometer, and tunable diode laser absorption spectroscopy (TDLAS). The destruction and removal efficiency (DRE) of CF4 and CHF3 were measured by a quadrupole mass spectroscopy (QMS) with the various operation conditions. The effect of the addition of the oxygen gas were tested and also the correlation between the plasma parameters and the DRE are presented in this study. This work was supported by R&D Program of ``Plasma Advanced Technology for Agriculture and Food (Plasma Farming)'' through the National Fusion Research Institute of Korea (NFRI) funded by the Government funds.

  7. Toxic effects of perfluorinated compounds at human cellular level and on a model vertebrate.

    PubMed

    Rainieri, Sandra; Conlledo, Nadia; Langerholc, Tomaž; Madorran, Eneko; Sala, Martin; Barranco, Alejandro

    2017-03-09

    This work aims at deepening the understanding of the mode of action of some of the most prominent perfluorinated compounds (PFCs) by detecting in a realistic way their effects. To this end, after adjusting the exposure media taking into account the biological model employed and the physico-chemical properties of PFCs, we evaluated the toxic effects of PFOA, PFOS and PFNA in a human macrophage cell line (TLT cells) and in zebrafish embryos. We performed such evaluation on individual compounds and mixtures. Acute toxicity was greater for PFOS in zebrafish; however, it was greater for PFNA in TLT cells. PFNA was also the compound producing the greatest levels of oxidative stress, both in zebrafish and TLT cells. Additionally, in both biological systems, it showed a much stronger effect on mixtures in comparison to the others PFCs tested in this work. Mixture studies in zebrafish showed that acute toxicity depended on the concentration and that the mixture was far more toxic than the individual compounds. This study highlights the importance of studying PFCs in realistic conditions on various biological models.

  8. Contamination of perfluorinated compounds (PFCs) in Chao Phraya River and Bangpakong River, Thailand.

    PubMed

    Kunacheva, Chinagarn; Boontanon, Suwanna Kitpati; Fujii, Shigeo; Tanaka, Shuhei; Musirat, Chanatip; Artsalee, Chattakarn; Wongwattana, Thana

    2009-01-01

    Perfluorinated compounds (PFCs) have been used for many years, and are distributed all over the world. This study focused on occurrences of PFCs, especially perfluorooctane sulfonate (PFOS) and perfluorooctonoic acid (PFOA) in Thai rivers and industrial estate discharges, while comparing results with rivers of other Asian countries (Japan, China, and Malaysia). Surveys were conducted in Chao Phraya River, Bangpakong River and three industrial estates. A solid phase extraction (SPE) and HPLC-ESI-MS/MS were used for the analysis of these chemicals. The average concentrations of PFOS and PFOA were 1.9 and 4.7 ng/L, respectively in Chao Phraya River, while lower concentrations were detected in Bangpakong River with the averages of 0.7 ng/L for both PFOS and PFOA. Higher concentrations were detected in all industrial estate discharges with the averages of 64.3 ng/L for PFOA and 17.9 ng/L for PFOS., Total loadings from three industrial estates were 1.93 g/d for PFOS and 11.81 g/d for PFOA. The concentration levels in Thai rivers were less than rivers in Japan, China, and Malaysia. However, PFCs loading rate of Chao Phraya River was much higher than Yodo River (Japan), due to the higher flow rate. The other six PFCs were found above the Limit of Quantification (LOQ) in most samples. PFHxS and PFNA were also highly detected in some river samples.

  9. Effects of perfluorinated chemicals on thyroid function, markers of ovarian reserve, and natural fertility.

    PubMed

    Crawford, Natalie M; Fenton, Suzanne E; Strynar, Mark; Hines, Erin P; Pritchard, David A; Steiner, Anne Z

    2017-01-19

    Perfluorinated chemicals (PFCs) can act as endocrine-disrupting chemicals, but there has been limited study of their effects on ovarian reserve or fecundability. 99 women, 30-44 years old, without infertility were followed until pregnancy. Initially, serum was evaluated for Antimullerian hormone (AMH), thyroid hormones: thyroid stimulating hormone (TSH), thyroxine (T4), free thyroxine (fT4), and triiodothyronine (T3), and PFCs: perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), and perfluorohexanesulfonic acid (PFHxS). Bivariate analyses assessed the relationship between thyroid hormones, AMH, and PFCs. Fecundability ratios (FR) were determined for each PFC using a discrete time-varying Cox model and a day-specific probability model. PFC levels were positively correlated with each other (r 0.24-0.90), but there was no correlation with TSH (r 0.02-0.15) or AMH (r -0.01 to -0.15). FR point estimates for each PFC were neither strong nor statistically significant. Although increased exposure to PFCs correlates with thyroid hormone levels, there is no significant association with fecundability or ovarian reserve.

  10. Effect of effluent organic matter on the adsorption of perfluorinated compounds onto activated carbon.

    PubMed

    Yu, Jing; Lv, Lu; Lan, Pei; Zhang, Shujuan; Pan, Bingcai; Zhang, Weiming

    2012-07-30

    Effect of effluent organic matter (EfOM) on the adsorption of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) onto powdered activated carbon (PAC) was quantitatively investigated at environmentally relevant concentration levels. The adsorption of both perfluorinated compounds (PFCs) onto PAC followed pseudo-second order kinetics and fitted the Freundlich model well under the given conditions. Intraparticle diffusion was found to be the rate-controlling step in the PFC adsorption process onto PAC in the absence and presence of EfOM. The presence of EfOM, either in PFC-EfOM simultaneous adsorption onto fresh PAC or in PFC adsorption onto EfOM-preloaded PAC, significantly reduced the adsorption capacities and sorption rates of PFCs. The pH of zero point of charge was found to be 7.5 for fresh PAC and 4.2 for EfOM-preloaded PAC, suggesting that the adsorbed EfOM imparted a negative charge on PAC surface. The effect of molecular weight distribution of EfOM on the adsorption of PFCs was investigated with two EfOM fractions obtained by ultrafiltration. The low-molecular-weight compounds (<1kDa) were found to be the major contributors to the significant reduction in PFC adsorption capacity, while large-molecular-weight compounds (>30kDa) had much less effect on PFC adsorption capacity.

  11. Contamination by perfluorinated compounds in water near waste recycling and disposal sites in Vietnam.

    PubMed

    Kim, Joon-Woo; Tue, Nguyen Minh; Isobe, Tomohiko; Misaki, Kentaro; Takahashi, Shin; Viet, Pham Hung; Tanabe, Shinsuke

    2013-04-01

    There are very few reports on the contamination by perfluorinated chemicals (PFCs) in the environment of developing countries, especially regarding their emission from waste recycling and disposal sites. This is the first study on the occurrence of a wide range of PFCs (17 compounds) in ambient water in Vietnam, including samples collected from a municipal dumping site (MD), an e-waste recycling site (ER), a battery recycling site (BR) and a rural control site. The highest PFC concentration was found in a leachate sample from MD (360 ng/L). The PFC concentrations in ER and BR (mean, 57 and 16 ng/L, respectively) were also significantly higher than those detected in the rural control site (mean, 9.4 ng/L), suggesting that municipal solid waste and waste electrical and electronic equipment are potential contamination sources of PFCs in Vietnam. In general, the most abundant PFCs were perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluoroundecanoic acid (PFUDA; <1.4-100, <1.2-100, and <0.5-20 ng/L, respectively). Interestingly, there were specific PFC profiles: perfluoroheptanoic acid and perfluorohexanoic acid (88 and 77 ng/L, respectively) were almost as abundant as PFOA in MD leachate (100 ng/L), whereas PFNA was prevalent in ER and BR (mean, 17 and 6.2 ng/L, respectively) and PFUDA was the most abundant in municipal wastewater (mean, 5.6 ng/L), indicating differences in PFC contents in different waste materials.

  12. Perfluorinated compounds in tap water from China and several other countries.

    PubMed

    Mak, Yim Ling; Taniyasu, Sachi; Yeung, Leo W Y; Lu, Guohui; Jin, Ling; Yang, Yongliang; Lam, Paul K S; Kannan, Kurunthachalam; Yamashita, Nobuyoshi

    2009-07-01

    The recent development of a sensitive and accurate analytical method for the analysis of 20 perfluorinated compounds (PFCs), including several short-chain PFCs, has enabled their quantification in tap water collected in China, Japan, India, the United States, and Canada between 2006 and 2008. Of the PFCs measured, PFOS, PFHxS, PFBS, PFPrS, PFEtS, PFOSA, N-EtFOSAA, PFDoDA, PFUnDA, PFDA, PFNA, PFHpA, PFHxA, PFPeA, PFBA, and PFPrA were found at detectable concentrations in the tap water samples. The water samples from Shanghai (China) contained the greatest concentrations of total PFCs (arithmetic mean = 130 ng/L), whereas those from Toyama (Japan) contained only 0.62 ng/L. In addition to PFOS and PFOA, short-chain PFCs such as PFHxS, PFBS, PFHxA, and PFBA were found to be prevalent in drinking water. According to the health-based values (HBVs) and advisory guidelines derived for PFOS, PFOA, PFBA, PFHxS, PFBS, PFHxA, and PFPeA by the U.S.EPA and the Minnesota Department of Health, tap water may not pose an immediate health risk to consumers.

  13. Detection of a cyclic perfluorinated acid, perfluoroethylcyclohexane sulfonate, in the Great Lakes of North America.

    PubMed

    De Silva, Amila O; Spencer, Christine; Scott, Brian F; Backus, Sean; Muir, Derek C G

    2011-10-01

    Perfluoroethylcyclohexanesulfonate (PFECHS) is a cyclic perfluorinated acid (PFA) mainly used as an erosion inhibitor in aircraft hydraulic fluids. It is expected to be as recalcitrant to environmental degradation as aliphatic PFAs including perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS). For the first time, PFECHS is reported in top predator fish (

  14. Perfluorinated alkyl substances (PFASs) in household dust in Central Europe and North America.

    PubMed

    Karásková, Pavlína; Venier, Marta; Melymuk, Lisa; Bečanová, Jitka; Vojta, Šimon; Prokeš, Roman; Diamond, Miriam L; Klánová, Jana

    2016-09-01

    Concentrations of 20 perfluorinated alkyl substances (PFASs) were measured in dust samples from 41 homes in Canada, the Czech Republic, and United States in the spring-summer of 2013. The most frequently detected compounds were perfluorohexanoic acid (PFHxA) and perfluorooctane sulfonate (PFOS). PFOS and perfluorooctanoic acid (PFOA) had the highest concentrations of PFASs in all countries. PFOS median concentrations for the three countries were between 9.1 and 14.1ng/g, and PFOA medians ranged between 8.2 and 9.3ng/g. In general, concentrations in North America were higher than in the Czech Republic, which is consistent with usage patterns. No differences were found for perfluorooctane sulfonamides/sulfonamidoethanols (FOSA/Es) levels due to the low number of detections. Homologue profiles suggest that the shift from longer to shorter chain PFASs is more advanced in North America than in Europe. Significant relationships were found among individual homologues and between PFAS concentrations in dust and type of floor, number of people living in the house, and building age.

  15. Pine Needles for the Screening of Perfluorinated Alkylated Substances (PFASs) along Ski Tracks.

    PubMed

    Chropeňová, Mária; Karásková, Pavlína; Kallenborn, Roland; Gregušková, Eva Klemmová; Čupr, Pavel

    2016-09-06

    Perfluorinated alkylated substances (PFASs) are today considered persistent, toxic, and bioaccumulative contaminants. Perfluorooctansulfonate (PFOS) and perfluorooctanoic acid (PFOA) are currently listed as priority substances under the UNEP global convention for the regulation of POPs. A previous study reported higher levels of PFASs in pine needles near ski areas. Their application as stain repellents in modern outdoor clothes and in ski waxes is assumed to be a potential source. Pine trees (Pinus mugo in Slovakia and Pinus sylvestris in Norway) were chosen for sampling in ski resorts. Relative distributions, overall concentrations, trend estimates, elevation patterns, and distance from primary sources were assessed. PFOA was the predominant PFAS constituent in pine needles from Slovakia (8-93%). In Norway, the most-abundant PFAS was perfluorobutanoic acid (PFBA: 3-66%). A difference in product composition (particularly in ski waxes) and differences in Norwegian and Slovakian regulations are considered to be the primary reason for these differences. Open application of PFOA in industry and products has been banned in Norway since 2011. The replacement of PFOA with short-chain substitutes is thus considered the reason for the observed pattern differences in the analyzed pine needles. Regular monitoring and screening programs are recommended.

  16. Adsorption of perfluorinated compounds on aminated rice husk prepared by atom transfer radical polymerization.

    PubMed

    Deng, Shubo; Niu, Li; Bei, Yue; Wang, Bin; Huang, Jun; Yu, Gang

    2013-04-01

    Adsorption is considered as an effective method to remove perfluorinated compounds (PFCs) from aqueous solution. In this study, an aminated rice husk (RH) adsorbent was successfully prepared through surface-initiated atom transfer radical polymerization (ATRP) and subsequent amination reaction, and it was used to remove perfluorooctanoate (PFOA), perfluorobutanoic acid (PFBA) and perfluorooctane sulfonate (PFOS) from aqueous solution. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analysis verified the presence of grafted polymer brushes and amine groups on the RH surface. The zero point of zeta potential of aminated RH was 8.5, which facilitated the sorption of anionic PFCs on the positively charged adsorbent at pH below 8.5. The sorption equilibria of PFOA, PFBA and PFOS were achieved within 5 h, 3 h and 9 h, respectively, faster than the reported porous adsorbents. Sorption isotherms showed that the adsorption capacities of PFOA, PFBA and PFOS on the aminated RH at pH 5.0 were 2.49, 1.70 and 2.65 mmol g(-1), respectively. Sorption behavior and X-ray photoelectron spectroscopy (XPS) analysis confirmed that the electrostatic and hydrophobic interactions were involved in the sorption process, and the micelles and hemi-micelles of PFOA and PFOS may form on the adsorbent surface.

  17. Perfluorinated chemicals infiltrate ocean waters: link between exposure levels and stable isotope ratios in marine mammals.

    PubMed

    Van de Vijver, Kristin Inneke; Hoff, Philippe Tony; Das, Krishna; Van Dongen, Walter; Esmans, Eddy Louis; Jauniaux, Thierry; Bouquegneau, Jean-Marie; Blust, Ronny; de Coen, Wim

    2003-12-15

    This is the first study to report on concentrations of perfluorinated organochemicals (FOCs) in marine mammals stranded along the southern North Sea coast in relation to stable nitrogen and carbon isotope ratios (delta15N and delta13C). The presence of FOCs in top predators such as marine mammals would indicate a potential biomagnification of these compounds and their widespread occurrence. Liver and kidney tissues of nine marine mammal species have been sampled. Among all the measured FOCs compounds, PFOS (perfluorooctane sulfonate) was predominant in terms of concentration. The highest PFOS concentrations were found in the liver of harbor seal compared to white-beaked dolphin, harbor porpoise, gray seal, sperm whale, white-sided dolphin, striped dolphin, fin whale, and hooded seal. PFOS concentrations differed significantly between sexes and age classes in harbor porpoises. Stable isotope measurements (delta13C and delta15N) were used in this study to describe the behavior of contaminants in food webs. We found a significant (p < 0.05) linear relationship between PFOS concentrations in livers of harbor porpoises and both muscle delta13C and delta15N measurements. Harbor and gray seals and white-beaked dolphin, which displayed the highest trophic position, contained the highest PFOS levels, while offshore feeders such as sperm whales, fin whales, striped dolphin, and white-sided dolphin showed lower PFOS concentrations than inshore species.

  18. Association between perfluorinated compounds and pathological conditions in southern sea otters

    USGS Publications Warehouse

    Kannan, K.; Perrotta, E.; Thomas, N.J.

    2006-01-01

    Concentrations of four perfluorinated contaminants, including perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA), were measured in liver tissue from 80 adult female sea otters collected from the California coast during 1992a??2002. Concentrations of PFOS and PFOA were in the ranges of <1a??884 and <5a??147 ng/g, wet wt, respectively. Concentrations of PFOA in the livers of these sea otters were among the highest values reported for marine mammals to date. Liver tissue from 6 male sea otters also was analyzed and contained significantly higher concentrations of PFOS than did tissues from female otters. To examine the association between exposures and potential effects, concentrations of PFOS and PFOA were compared among the adult female otters that died from infectious diseases, noninfectious causes, and from apparent emaciation. Concentrations of both PFOA and PFOS were significantly higher in sea otters in the infectious disease category than in the noninfectious category. Concentrations of PFOS and PFOA were not significantly different between noninfectious and emaciated otters, suggesting that the poor nutritive (body) status of emaciated otters did not affect the concentrations of perfluorochemicals in livers. Concentrations of PFOA increased significantly from 1992 to 2002, whereas PFOS concentrations increased from 1992 to 1998 and then decreased after 2000. Significant association between infectious diseases and elevated concentrations of PFOS/PFOA in the livers of sea otters is a cause for concern and suggests the need for further studies.

  19. Association between perfluorinated compounds and pathological conditions in southern sea otters.

    PubMed

    Kannan, Kurunthachalam; Perrotta, Emily; Thomas, Nancy J

    2006-08-15

    Concentrations of four perfluorinated contaminants, including perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA), were measured in liver tissue from 80 adult female sea otters collected from the California coast during 1992-2002. Concentrations of PFOS and PFOA were in the ranges of <1-884 and <5-147 ng/g, wet wt, respectively. Concentrations of PFOA in the livers of these sea otters were among the highest values reported for marine mammals to date. Liver tissue from 6 male sea otters also was analyzed and contained significantly higher concentrations of PFOS than did tissues from female otters. To examine the association between exposures and potential effects, concentrations of PFOS and PFOA were compared among the adult female otters that died from infectious diseases, noninfectious causes, and from apparent emaciation. Concentrations of both PFOA and PFOS were significantly higher in sea otters in the infectious disease category than in the noninfectious category. Concentrations of PFOS and PFOA were not significantly different between noninfectious and emaciated otters, suggesting that the poor nutritive (body) status of emaciated otters did not affectthe concentrations of perfluorochemicals in livers. Concentrations of PFOA increased significantly from 1992 to 2002, whereas PFOS concentrations increased from 1992to 1998 and then decreased after 2000. Significant association between infectious diseases and elevated concentrations of PFOS/PFOA in the livers of sea otters is a cause for concern and suggests the need for further studies.

  20. Biomonitoring and Elimination of Perfluorinated Compounds and Polychlorinated Biphenyls through Perspiration: Blood, Urine, and Sweat Study

    PubMed Central

    Genuis, Stephen J.; Beesoon, Sanjay; Birkholz, Detlef

    2013-01-01

    Perfluorinated compounds (PFCs) are man-made organofluorine chemicals manufactured and marketed for their stain-resistant properties. Polychlorinated biphenyls (PCBs) are anthropogenic organochlorine compounds previously used in various industrial and chemical applications prior to being banned in the Western world in the 1970s. Both PFCs and PCBs are persistent contaminants within the human organism and both have been linked to adverse health sequelae. Data is lacking on effective means to facilitate clearance of PFCs and PCBs from the body. Methods. Blood, urine, and sweat were collected from 20 individuals (10 healthy participants and 10 participants with assorted health problems) and analyzed for PFCs and PCBs using high performance liquid chromatography tandem mass spectrometry. Results. Some individual PCB congeners, but not all, were released into sweat at varying concentrations. None of the PFCs found in serum testing appeared to be excreted efficiently into perspiration. Conclusions. Induced perspiration may have some role in facilitating elimination of selected PCBs. Sweat analysis may be helpful in establishing the existence of some accrued PCBs in the human body. Sweating does not appear to facilitate clearance of accrued PFHxS (perfluorohexane sulfonate), PFOS (perfluorooctane sulfonate), or PFOA (perfluorooctanoic acid), the most common PFCs found in the human body. PMID:24083032

  1. [Influence of tap water treatment on perfluorinated compounds residue in the dissolved phase].

    PubMed

    Zhang, Hong; Chen, Qing-wu; Wang, Xin-xuan; Chai, Zhi-fang; Shen, Jin-can; Yang, Bo; Liu, Guo-qing

    2013-09-01

    To study the perfluorinated compounds (PFCs) residues through water treatments including flocculation, sedimentation, sand filtration, ozonation with activated carbon and chlorination, as well as the seasonal variation of PFCs in the raw water of waterworks, 13 PFCs species in the dissolved phase of raw water, finished water, as well as the water samples after flocculation, sedimentation, sand filtration, and ozonation with activated carbon filtration were measured by the high performance liquid chromatography-tandem mass spectrometry combined with solid phase extraction. Results indicated that sigma PFCs residue in water was higher in spring and summer than that in fall and winter. The vast majority of PFCs in samples were of short and medium chains (C < or = 10), and perfluorooctane sulfonate was the most typical residue species. Among the five water treatment stages, sedimentation, sand filtration and ozonation with activated carbon filtration can remove PFCs, while flocculation and chlorination significantly raise the levels of short- (C < or = 6) and medium-chain (10 > or = C > or = 7) PFCs, respectively, causing sigma PFCs increase in finished water by 10%-44% compared to raw water. However, the PFCs residues in finished water are still far below their limit values, posing no threat against human health.

  2. Dietary predictors and plasma concentrations of perfluorinated alkyl acids in a Singapore population.

    PubMed

    Liu, Yu; Su, Jin; van Dam, Rob M; Prem, Kiesha; Hoong, Joey Y S; Zou, Li; Lu, Yonghai; Ong, Choon Nam

    2017-03-01

    Perfluorinated alkyl acids (PFAAs), a family of man-made organofluorinated compounds, have drawn much attention due to their ubiquitous existence in the environment and their bioaccumulation potential. Here, we examined the plasma concentrations of thirteen PFAAs in a healthy population (N = 270) in Singapore, and investigated the association between major food groups and plasma PFAA concentrations. We detected eight types of PFAAs in more than 75% of all samples (N = 270), and their median concentrations ranged from 0.05 to 8.34 ng mL(-1). Age- and gender-related differences were observed for the three dominant PFAAs, i.e., perfluorooctanesulfonic acid (PFOS), perfluorohexane sulfonate (PFHxS) and perfluorooctanoate acid (PFOA), with concentrations being higher in men and older adults. Multiple linear regression analyses showed that fish, shellfish, red meat and poultry were associated with increased PFAAs concentrations in plasma, whereas grains and soy products showed inverse associations with PFAAs. Further, significant correlations were observed between various long-chain PFAAs and plasma concentrations of omega-3 fatty acids, suggesting seafood was a significant source of these PFAAs, within this population. Future studies on diet exposure to PFAAs are encouraged to focus more on the effects on diet pattern.

  3. [Residue characteristics and distributions of perfluorinated compounds in surface seawater along Shenzhen coastline].

    PubMed

    Chen, Qing-Wu; Zhang, Hong; Chai, Zhi-Fang; Shen, Jin-Can; Yang, Bo

    2012-06-01

    In order to explore the residue characteristics and distributions of 15 perfluorinated compounds (PFCs) in 18 surface seawater samples along Shenzhen coastline, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) combined with solid phase extraction enrichment was applied in this research. The results indicated that residue level of PFCs in coastal surface seawater samples was significantly affected by human activities. Sigma PFCs residue levels in surface seawater from Shenzhen west coast, which locates below the estuary of Pearl River and Donghao River, are much higher than those from the east coast, which has low development and sparse population (P<0.05). Under natural conditions, sigma PFCs residue levels in coastal surface seawater samples from Shenzhen Bays are higher than those out of bays. The major residue species in surface seawater samples along Shenzhen coast were medium- and short-chain PFCs, including perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanoic acid and perfluoropentanoic acid. Their similar environmental behavior (P<0.05, P<0.01) is likely associated with the production process of PFCs-related products. Furthermore, cluster analysis results show that PFOS (R2 = 0.4092) level can be used as a representative parameter for evaluating PFCs contamination status in surface seawater along Shenzhen coast.

  4. Understanding Potential Exposure Sources of Perfluorinated Carboxylic Acids in the Workplace

    PubMed Central

    Kaiser, Mary A.; Dawson, Barbara J.; Barton, Catherine A.; Botelho, Miguel A.

    2010-01-01

    This paper integrates perspectives from analytical chemistry, environmental engineering, and industrial hygiene to better understand how workers may be exposed to perfluorinated carboxylic acids when handling them in the workplace in order to identify appropriate exposure controls. Due to the dramatic difference in physical properties of the protonated acid form and the anionic form, this family of chemicals provides unique industrial hygiene challenges. Workplace monitoring, experimental data, and modeling results were used to ascertain the most probable workplace exposure sources and transport mechanisms for perfluorooctanoic acid (PFOA) and its ammonium salt (APFO). PFOA is biopersistent and its measurement in the blood has been used to assess human exposure since it integrates exposure from all routes of entry. Monitoring suggests that inhalation of airborne material may be an important exposure route. Transport studies indicated that, under low pH conditions, PFOA, the undissociated (acid) species, actively partitions from water into air. In addition, solid-phase PFOA and APFO may also sublime into the air. Modeling studies determined that contributions from surface sublimation and loss from low pH aqueous solutions can be significant potential sources of workplace exposure. These findings suggest that keeping surfaces clean, preventing accumulation of material in unventilated areas, removing solids from waste trenches and sumps, and maintaining neutral pH in sumps can lower workplace exposures. PMID:20974675

  5. Perfluorinated compounds in whole fish homogenates from the Ohio, Missouri, and Upper Mississippi Rivers, USA.

    PubMed

    Ye, Xibiao; Strynar, Mark J; Nakayama, Shoji F; Varns, Jerry; Helfant, Larry; Lazorchak, James; Lindstrom, Andrew B

    2008-12-01

    A method for the analysis of 10 perfluorinated compounds (PFCs) in whole fish homogenate is presented and applied to 60 fish samples collected from the Ohio, Missouri, and upper Mississippi Rivers in 2005. Method accuracy ranged between 86 and 125% with limits of quantitation between 0.2 and 10 ng/g wet weight. Intra- and inter-batch precision was generally +/-20%. Perfluorooctane sulfonate (PFOS) was the predominant compound identified in these samples, contributing over 80% of total PFC composition in the fish from these rivers, with median PFOS concentrations of 24.4, 31.8, and 53.9 ng/g wet wt in the Missouri, Ohio, and Mississippi Rivers, respectively. Median PFOS levels were significantly (p=0.01) elevated in piscivorous fish (88.0 ng/g) when compared with non-piscivorous fish (15.9 ng/g). The 10 samples with PFOS concentrations above 200 ng/g were broadly scattered across all three rivers, providing evidence of the widespread presence of this compound in these US waterways.

  6. Composition, distribution and risk of total fluorine, extractable organofluorine and perfluorinated compounds in Chinese teas.

    PubMed

    Zhang, Ruobing; Zhang, Hong; Chen, Qingwu; Luo, Ji; Chai, Zhifang; Shen, Jincan

    2017-03-15

    To explore the residual characteristics of fluorine and perfluorinated compounds (PFCs) in tea, the total fluorine (TF), extractable organofluorine (EOF) and PFCs in 19 Chinese commercial teas of five categories were measured using cyclic neutron activation analysis combined with HPLC-MS/MS. The results showed that fluorine mainly existed as inorganic fluorine in teas, and identified fluorine (∑PFCs quantified as F) only accounted for 0.023-0.41% of EOF, indicating that most EOF in tea were still unknown. 50-99% of ∑PFCs in tea were short-chain (C⩽6), while perfluorooctanoic acid was the typical PFCs residual species. Less fermented teas contained significantly higher PFCs (mean, 20ng/g) than more fermented teas (3.0ng/g, p<0.01), suggesting that microbe may degrade PFCs during fermentation. The highest TF content was discovered in Hubei brick tea, which poses risk of fluorosis, whereas PFCs residues in teas caused no immediate harm.

  7. Hydrophobicity-dependent QSARs to predict the toxicity of perfluorinated carboxylic acids and their mixtures.

    PubMed

    Wang, Ting; Lin, Zhifen; Yin, Daqiang; Tian, Dayong; Zhang, Yalei; Kong, Deyang

    2011-09-01

    Perfluorinated carboxylic acids (PFCAs) have wide industrial applications because of their unique physicochemical characteristics. However, data on the toxicity of much of this chemical class is lacking, particularly with regard to mixture toxicity. In this study, the toxicity of individual PFCAs and their mixtures to Photobacterium phosphoreum were observed. There was a tendency of increasing toxicity from C3 to C14 PFCA and a tendency of decreasing toxicity from C14 to C18 PFCA because of "the maximum tolerance of the cell membrane". Using the equivalent logK(OW) (octanol-water partition coefficient) and logK(SD) (C(18)-Empore™ disks/water partition coefficient), two linear quantitative structure-activity relationship (QSAR) models were formulated. This indicated both K(SD) and K(OW) can describe the hydrophobicity of a single chemical. However, for the PFCA mixtures, K(MD) is the more reasonable parameter than K(owmix) to describe the hydrophobicity because only the equivalent logK(MD) could be used to predict the mixture toxicity.

  8. An Integrated Modeling Approach for Describing Fate and Transport of Perfluorinated Compounds (PFCs) in Estuarine Reservoir

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Nguyen Viet, T.; Wang, X.; Chen, H.; Gin, K. Y. H.

    2014-12-01

    The fate and transport processes of emerging contaminants in aquatic ecosystems are complex, which are not only determined by their own properties but also influenced by the environmental setting, physical, chemical and biological processes. A 3D-emerging contaminant model has been developed based on Delft3D water quality model and coupled with a hydrodynamic model and a catchment-scale 1D- hydrological and hydraulic model to study the possible fate and transport mechanisms of perfluorinated compounds (PFCs) in Marina Reservoir in Singapore. The main processes in the contaminant model include partitioning (among detritus, dissolved organic matter and phytoplankton), settling, resuspension and degradation. We used the integrated model to quantify the distribution of the total PFCs and two major components, namely perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in the water, sediments and organisms in the reservoir. The model yielded good agreement with the field measurements when evaluated based on the datasets in 2009 and 2010 as well as recent observations in 2013 and 2014. Our results elucidate that the model can be a useful tool to characterize the occurrence, sources, sinks and trends of PFCs both in the water column and in the sediments in the reservoir. Thisapproach provides a better understanding of mechanisms that influence the fate and transport of emerging contaminants and lays down a framework for future experiments to further explore how the dominant environmental factors change towards mitigation of emerging contaminants in the reservoirs.

  9. Prediction of aqueous solubility, vapor pressure and critical micelle concentration for aquatic partitioning of perfluorinated chemicals.

    PubMed

    Bhhatarai, Barun; Gramatica, Paola

    2011-10-01

    The majority of perfluorinated chemicals (PFCs) are of increasing risk to biota and environment due to their physicochemical stability, wide transport in the environment and difficulty in biodegradation. It is necessary to identify and prioritize these harmful PFCs and to characterize their physicochemical properties that govern the solubility, distribution and fate of these chemicals in an aquatic ecosystem. Therefore, available experimental data (10-35 compounds) of three important properties: aqueous solubility (AqS), vapor pressure (VP) and critical micelle concentration (CMC) on per- and polyfluorinated compounds were collected for quantitative structure-property relationship (QSPR) modeling. Simple and robust models based on theoretical molecular descriptors were developed and externally validated for predictivity. Model predictions on selected PFCs were compared with available experimental data and other published in silico predictions. The structural applicability domains (AD) of the models were verified on a bigger data set of 221 compounds. The predicted properties of the chemicals that are within the AD, are reliable, and they help to reduce the wide data gap that exists. Moreover, the predictions of AqS, VP, and CMC of most common PFCs were evaluated to understand the aquatic partitioning and to derive a relation with the available experimental data of bioconcentration factor (BCF).

  10. Perfluorinated acid isomer profiling in water and quantitative assessment of manufacturing source.

    PubMed

    Benskin, Jonathan P; Yeung, Leo W Y; Yamashita, Nobuyoshi; Taniyasu, Sachi; Lam, Paul K S; Martin, Jonathan W

    2010-12-01

    A method for isomer profiling of perfluorinated compounds (PFCs) in water was developed and applied to quantitatively assess the contributions from electrochemical (ECF) and telomer manufacturing processes around source regions of North America, Asia, and Europe. With the exception of 3 sites in Japan, over 80% of total perfluorooctanoate (PFOA, C(7)F(15)COO(-)) was from ECF, with the balance attributable to strictly linear (presumably telomer) manufacturing source(s). Comparing PFOA isomer profiles in samples from China, with PFOA obtained from a local Chinese manufacturer, indicated <3% difference in overall branched isomer content; thus, exclusive contribution from local ECF production cannot be ruled out. In Tokyo Bay, ECF, linear-telomer, and isopropyl-telomer sources contributed to 33%, 53%, and 14% of total PFOA, respectively. Perfluorooctane sulfonate (PFOS, C(8)F(17)SO(3)(-)) isomer profiles were enriched in branched content (i.e., >50% branched) in the Mississippi River but in all other locations were similar or only slightly enriched in branched content relative to historical ECF PFOS. Isomer profiles of other PFCs are also reported. Overall, these data suggest that, with the exception of Tokyo Bay, ECF manufacturing has contributed to the bulk of contamination around these source regions, but other sources are significant, and remote sites should be monitored.

  11. Novel Perfluorinated Polymer-Based Pervaporation Membranes for Separation of Solvent/Water Mixtures.

    PubMed

    Smuleac, V; Wu, J; Nemser, S; Majumdar, S; Bhattacharyya, D

    2010-04-15

    Traditionally, the pervaporation of water-solvent mixtures where the solvent is the major component is performed using hydrophilic membranes (such as PVA or zeolites). In the present paper a new type of pervaporation membrane (amorphous perfluorinated polymer, hydrophobic) was studied for separation of water-solvent mixtures. This membrane has high free volume and is inert for all solvents, and has a remarkable mechanical, chemical and thermal stability. The water is transported by solution diffusion model and the separation of solvent is primarily based on molecular sieving (size exclusion) principles. The membrane shows a high stability for operation over a broad range of feed concentrations without swelling; the operating temperature does not have a significant effect on membrane separation performance. Separation factors as high as 349 and 500 for water-ethanol and water-IPA mixtures (2-98 % wt water-solvent) and fluxes of 0.15 and 0.05 kg/m(2)h, respectively were obtained at 22 °C. The permeance-based selectivities were also calculated, and the selectivity is approximately constant for a wide range of feed concentrations. The pervaporation of more complex (ternary) mixtures of water-ethanol-ethyl acetate showed that this system could be successfully applied for solute separation based on size exclusion.

  12. Occurrence of perfluorinated compounds in water, sediment and mussels from the Cantabrian Sea (North Spain).

    PubMed

    Gómez, Cristian; Vicente, Joana; Echavarri-Erasun, Beatriz; Porte, Cinta; Lacorte, Silvia

    2011-05-01

    Perfluorinated compounds (PFCs) have emerged as significant global environmental pollutants with persistent, bioaccumulative and toxic properties. The aim of this study was to determine the occurrence of PFCs in water (wastewater, submarine emissaries and port-waters), sediment and transplanted mussels in estuarine areas of high urban and industrial impact from Northern Spain. Five PFCs of industrial use were studied: perfluorooctanesulfonate, perfluorohexanesulfonate, perfluorobutanesulfonate, perfluorooctanoate acid and perfluorononanoate acid. After selective extraction, samples were analyzed by Ultra Performance Liquid Chromatography coupled to tandem mass spectrometry. ΣPFCs ranged from 0.06 to 10.9 ng/L in water, with higher levels in wastewater treatment plants effluents and port waters than in submarine emissaries. Little accumulation was observed in sediments and mussels with ΣPFCs ranging from 0.01-0.13 ng/g dw and 0.01-0.06 ng/g ww, respectively. Most ubiquitous compounds were PFOS and PFOA. Mass fluxes of PFCs to the Cantabrian Sea are estimated and the impact to the coastal ecosystem is discussed.

  13. Geographical distribution of perfluorinated compounds in fish from Minnesota lakes and rivers.

    PubMed

    Delinsky, Amy D; Strynar, Mark J; McCann, Patricia J; Varns, Jerry L; McMillan, Larry; Nakayama, Shoji F; Lindstrom, Andrew B

    2010-04-01

    In response to growing interest in human exposure to perfluorinated compounds (PFCs), the state of Minnesota measured and reported PFC concentrations in fish collected from the Minneapolis-St. Paul area. To better determine the geographical distribution of PFC contamination throughout Minnesota, fish were collected from 59 lakes throughout the state and several areas along the Mississippi River. Composite fish samples were analyzed for 10 PFC analytes by solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC/MS/MS). PFOS (perfluorooctanesulfonate) was the most commonly detected PFC, occurring in 73% of fish from the Mississippi River but only 22% of fish from lakes. Fish from Mississippi River Pool 2 near the Minneapolis-St. Paul area had the highest levels of PFOS, whereas locations upstream had PFOS concentrations below 40 ng/g, the concentration at which Minnesota issues "one meal per week" fish consumption advice. Fish from most Minnesota lakes tested (88%) had PFOS concentrations below 3 ng/g. Two lakes, McCarrons and Zumbro, contained fish with PFOS levels above 40 ng/g. The results reported here will help researchers to better understand the extent of PFC contamination in Minnesota fish and evaluate potential sources of contamination and will provide a basis for comprehensive fish consumption advice.

  14. Time trends of perfluorinated compounds from the sediment core of Tokyo Bay, Japan (1950s-2004).

    PubMed

    Zushi, Yasuyuki; Tamada, Masafumi; Kanai, Yutaka; Masunaga, Shigeki

    2010-03-01

    Perfluorinated compounds (PFCs) were detected in sediment core samples collected in Tokyo Bay to reveal their time trends. The core sample deposited during 1950s-2004 was divided into two- to three-year intervals and the concentrations of 24 types of PFCs were determined. Perfluorooctane sulfonate (PFOS) decreased gradually from the early 1990s and its precursor decreased rapidly in the late 1990s, whereas perfluorooctanoic acid (PFOA) increased rapidly. The observed trends were regarded as a reflection of the shift from perfluorooctyl sulfonyl fluoride (PFOSF)-based products to telomer-based products after the phaseout of PFOSF-based products in 2001. The branched isomers of perfluoroundecanoic acid (PFUnDA) and perfluorotridecanoic acid (PFTrDA) were detected in the sample with its ratio of linear-isomer/branched-isomer concentrations decreasing. In this study, we revealed that the sediment core can serve as a tool for reconstructing the past pollution trend of PFCs and can provide interesting evidence concerning their environmental dynamics and time trend.

  15. [Pollution fingerprints and sources of perfluorinated compounds in surface soil of different functional areas].

    PubMed

    Zhang, Hong; Zhao, Liang; He, Long; Chai, Zhi-Fang; Shen, Jin-Can; Yang, Bo

    2014-07-01

    In order to explore the effect of regional functions on the pollution fingerprints and levels of perfluorinated compounds (PFCs), principal components analysis was combined with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and solid phase extraction enrichment in this research to analyze the levels of 14 PFCs species in 76 surface soil samples, which were collected from 4 functional regions, namely parks, communities, crossroads and surroundings of factories, as well as the urban background of Shenzhen. The results showed that regional functions had significant effect on total PFCs (sigma PFCs), which ranked as the following: surroundings of factories (P < 0.001) > crossroads (P < 0.01) > communities (P < 0.05) > parks > urban background. The distribution of PFCs was in the order of medium- (P < 0.05) > long- > short-chain PFCs in surroundings of factories, communities and crossroads, while in the order of medium- approximately short- (P < 0.05) > long chain PFCs in crossroads. Over 81% of sigmaPFCs in the surface soil of Shenzhen could be attributed to the three principal components, represented by perfluorooctane sulfonate, perfluorooctane acid and perfluorotridecanoic acid, respectively. PFCs fingerprints were clearly shown in crossroads, as well as in surroundings of electroplating and paint factories.

  16. Dietary Predictors and Plasma Concentrations of Perfluorinated Compounds in a Coastal Population from Northern Norway

    PubMed Central

    Rylander, Charlotta; Brustad, Magritt; Falk, Helena; Sandanger, Torkjel M.

    2009-01-01

    Dietary intake, age, gender, and body mass index were investigated as possible predictors of perfluorinated compounds in a study population from northern Norway (44 women and 16 men). In addition to donating a blood sample, the participants answered a detailed questionnaire about diet and lifestyle. Perfluorooctane sulfonate (PFOS) (29 ng/mL), perfluorooctanoate (PFOA) (3.9 ng/mL), perfluorohexane sulfonate (PFHxS) (0.5 ng/mL), perfluorononanoate (PFNA) (0.8 ng/mL), and perfluoroheptane sulfonate (PFHpS) (1.1 ng/mL) were detected in more than 95% of all samples. Of the dietary items investigated, fruit and vegetables significantly reduced the concentrations of PFOS and PFHpS, whereas fatty fish to a smaller extent significantly increased the levels of the same compounds. Men had significantly higher concentrations of PFOS, PFOA, PFHxS, and PFHpS than women. There were significant differences in PFOS isomer pattern between genders, with women having the largest proportion of linear PFOS. PFOS, PFHxS, and PFHpS concentrations also increased with age. PMID:20111729

  17. Laser Damage Precursors in Fused Silica

    SciTech Connect

    Miller, P; Suratwala, T; Bude, J; Laurence, T A; Shen, N; Steele, W A; Feit, M; Menapace, J; Wong, L

    2009-11-11

    There is a longstanding, and largely unexplained, correlation between the laser damage susceptibility of optical components and both the surface quality of the optics, and the presence of near surface fractures in an optic. In the present work, a combination of acid leaching, acid etching, and confocal time resolved photoluminescence (CTP) microscopy has been used to study laser damage initiation at indentation sites. The combination of localized polishing and variations in indentation loads allows one to isolate and characterize the laser damage susceptibility of densified, plastically flowed and fractured fused silica. The present results suggest that: (1) laser damage initiation and growth are strongly correlated with fracture surfaces, while densified and plastically flowed material is relatively benign, and (2) fracture events result in the formation of an electronically defective rich surface layer which promotes energy transfer from the optical beam to the glass matrix.

  18. Understanding error generation in fused deposition modeling

    NASA Astrophysics Data System (ADS)

    Bochmann, Lennart; Bayley, Cindy; Helu, Moneer; Transchel, Robert; Wegener, Konrad; Dornfeld, David

    2015-03-01

    Additive manufacturing offers completely new possibilities for the manufacturing of parts. The advantages of flexibility and convenience of additive manufacturing have had a significant impact on many industries, and optimizing part quality is crucial for expanding its utilization. This research aims to determine the sources of imprecision in fused deposition modeling (FDM). Process errors in terms of surface quality, accuracy and precision are identified and quantified, and an error-budget approach is used to characterize errors of the machine tool. It was determined that accuracy and precision in the y direction (0.08-0.30 mm) are generally greater than in the x direction (0.12-0.62 mm) and the z direction (0.21-0.57 mm). Furthermore, accuracy and precision tend to decrease at increasing axis positions. The results of this work can be used to identify possible process improvements in the design and control of FDM technology.

  19. Itinerant Conductance in Fuse-Antifuse Networks

    NASA Astrophysics Data System (ADS)

    Filho, Cesar I. N. Sampaio; Moreira, André A.; Araújo, Nuno A. M.; Andrade, José S.; Herrmann, Hans J.

    2016-12-01

    We report on a novel dynamic phase in electrical networks, in which current channels perpetually change in time. This occurs when the elementary units of the network are fuse-antifuse devices, namely, become insulators within a certain finite interval of local applied voltages. As a consequence, the macroscopic current exhibits temporal fluctuations which increase with system size. We determine the conditions under which this exotic situation appears by establishing a phase diagram as a function of the applied field and the size of the insulating window. Besides its obvious application as a versatile electronic device, due to its rich variety of behaviors, this network model provides a possible description for particle-laden flow through porous media leading to dynamical clogging and reopening of the local channels in the pore space.

  20. Multicomponent synthesis of 3,6-dihydro-2H-1,3-thiazine-2-thiones.

    PubMed

    Kruithof, Art; Ploeger, Marten L; Janssen, Elwin; Helliwell, Madeleine; de Kanter, Frans J J; Ruijter, Eelco; Orru, Romano V A

    2012-02-08

    Non-fused 3,6-dihydro-2H-1,3-thiazine-2-thiones constitute a so far rather unexplored class of compounds, with the latest report dating back more than two decades. Thiazine-2-thiones contain an endocyclic dithiocarbamate group, which is often found in pesticides, in substrates for radical chemistry and in synthetic intermediates towards thioureas and amidines. We now report the multicomponent reaction (MCR) of in situ-generated 1-azadienes with carbon disulfide. With this reaction, a one-step protocol towards the potentially interesting 3,6-dihydro-2H-1,3-thiazine-2-thiones was established and a small library was synthesized.

  1. FUSE Observations of Luminous Cool Stars

    NASA Astrophysics Data System (ADS)

    Dupree, A. K.; Young, P. R.; Ake, T. B.

    2000-12-01

    Luminous cool stars can address the evolution of magnetic activity and the dynamics of stellar winds and mass loss. The region of yellow supergiants in the HR diagram contains stars of intermediate mass both with coronas and those possessing a hot outer atmosphere in the presence of a strong wind (the ``hybrid'' stars). These hybrid objects hold particular significance for evolution studies because they represent the physically important connection between solar-like stars (with coronas and fast winds of low-mass loss rate) and the cool supergiant stars (Alpha Ori-like) with cool outer atmospheres and massive winds. The Far Ultraviolet Spectroscopic Explorer (FUSE) measured the chromospheric and transition region emissions of the bright G2 Ib supergiant Beta Draconis (HD 159181) on 9 May 2000. Two exposures through the large aperture totaled 7695 s and were obtained in all channels covering the region λ λ 912-1180. Emission from chromospheric and transition region ions (C III, O VI, Si III, S IV, S VI) is detected along with a number of low ion stages. Profiles of strong lines are asymmetric suggesting the presence of a wind. A short exposure (3260 s) of Alpha Aquarii (HD 209750), a hybrid supergiant also of spectral type G2 Ib was obtained June 29, 2000. Dynamics of the atmospheres can be inferred from line profiles. The atmospheric temperature distribution, densities, and scale sizes can be evaluated from line fluxes to characterize the differences between a coronal star and a hybrid supergiant. FUSE is a NASA Origins mission operated by The Johns Hopkins University. Funding for this research is provided through NASA Contract NAS-532985.

  2. High Voltage Applications of Explosively Formed Fuses

    NASA Astrophysics Data System (ADS)

    Tasker, D. G.; Goforth, J. H.; Fowler, C. M.; Herrera, D. H.; King, J. C.; Lopez, E. A.; Martinez, E. C.; Oona, H.; Marsh, S. P.; Reinovsky, R. E.; Stokes, J.; Tabaka, L. J.; Torres, D. T.; Sena, F. C.; Kiuttu, G.; Degnan, J.

    2004-11-01

    At Los Alamos, we have primarily applied Explosively Formed Fuse (EFF) techniques to high current systems. In these systems, the EFF has interrupted currents from 19-25 MA, thus diverting the current to low inductance loads. The transferred current magnitude is determined by the ratio of storage inductance to load inductance and, with dynamic loads, the current has ranged from 12-20 MA. In a system with 18 MJ stored energy, the switch operates at a power of up to 6 TW. We are now investigating the use of the EFF technique to apply high voltages to high impedance loads in systems that are more compact. In these systems we are exploring circuits with EFF lengths from 43-100 cm, which have storage inductances large enough to apply 300-500 kV across high impedance loads. Experimental results and design considerations are presented. Using cylindrical EFF switches of 10 cm diameter and 43 cm length, currents of approximately 3 MA were interrupted producing ~200 kV. This indicates the switch had an effective resistance of ~100 mΩ where 150-200 mΩ was expected. To understand the lower performance, several parameters were studied including electrical conduction through the explosive products; current density; explosive initiation; insulator type and conductor thickness. The results show a number of interesting features, most notably that the primary mechanism of switch operation is mechanical and not electrical fusing of the conductor. Switches opening on a 1-10 μs time scale with resistances starting at 50 μΩ and increasing to perhaps 1 Ω now seem possible to construct using explosive charges as small as a few pounds.

  3. High Voltage Application of Explosively Formed Fuses

    SciTech Connect

    Tasker, D.G.; Goforth, J.H.; Fowler, C.M.; Lopez, E.M.; Oona, H.; Marsh, S.P.; King, J.C.; Herrera, D.H.; Torres, D.T.; Sena, F.C.; Martinez, E.C.; Reinovsky, R.E.; Stokes, J.L.; Tabaka, L.J.; Kiuttu, G.; Degnan, J.

    1998-10-18

    At Los Alamos, the authors have primarily applied Explosively Formed Fuse (EFF) techniques to high current systems. In these systems, the EFF has interrupted currents from 19 to 25 MA, thus diverting the current to low inductance loads. The magnitude of transferred current is determined by the ratio of storage inductance to load inductance, and with dynamic loads, the current has ranged from 12 to 20 MA. In a system with 18 MJ stored energy, the switch operates at a power up to 6 TW. The authors are now investigating the use of the EFF technique to apply high voltages to high impedance loads in systems that are more compact. In these systems, they are exploring circuits with EFF lengths from 43 to 100 cm, which have storage inductances large enough to apply 300 to 500 kV across high impedance loads. Experimental results and design considerations are presented. Using cylindrical EFF switches of 10 cm diameter and 43 cm length, currents of approximately 3 MA were interrupted producing {approximately}200 kV. This indicate s the switch had an effective resistance of {approximately}100 m{Omega} where 150--200 m{Omega} was expected. To understand the lower performance, several parameters were studied, including: electrical conduction through the explosive products; current density; explosive initiation; insulator type; conductor thickness; and so on. The results show a number of interesting features, most notably that the primary mechanism of switch operation is mechanical and not electrical fusing of the conductor. Switches opening on a 10 to 10 {micro}s time scale with resistances starting at 50 {micro}{Omega} and increasing to perhaps 1 {Omega} now seem possible to construct, using explosive charges as small as a few pounds.

  4. 50 CFR 1.3 - Service.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 1 2010-10-01 2010-10-01 false Service. 1.3 Section 1.3 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR GENERAL PROVISIONS DEFINITIONS § 1.3 Service. Service means the United States Fish and Wildlife Service, Department of the Interior....

  5. 45 CFR 1216.1-3 - Policy.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 4 2011-10-01 2011-10-01 false Policy. 1216.1-3 Section 1216.1-3 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE NONDISPLACEMENT OF EMPLOYED WORKERS AND NONIMPAIRMENT OF CONTRACTS FOR SERVICE § 1216.1-3 Policy. (a) Volunteers enrolled or participating in...

  6. 45 CFR 1211.1-3 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 4 2011-10-01 2011-10-01 false Definitions. 1211.1-3 Section 1211.1-3 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE VOLUNTEER GRIEVANCE PROCEDURES § 1211.1-3 Definitions. (a) Volunteer means a person enrolled and currently serving as a full-time volunteer...

  7. 45 CFR 1210.1-3 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 4 2011-10-01 2011-10-01 false Definitions. 1210.1-3 Section 1210.1-3 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE VISTA TRAINEE DESELECTION AND VOLUNTEER EARLY TERMINATION PROCEDURES General § 1210.1-3 Definitions. (a) Trainee means a person enrolled in...

  8. 5 CFR 1.3 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Definitions. 1.3 Section 1.3 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE RULES COVERAGE AND DEFINITIONS (RULE I) § 1.3 Definitions. As used in the rules in this subchapter: (a) Competitive service shall have the...

  9. 43 CFR 8365.1-3 - Vehicles.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Vehicles. 8365.1-3 Section 8365.1-3 Public... OF THE INTERIOR RECREATION PROGRAMS VISITOR SERVICES Rules of Conduct § 8365.1-3 Vehicles. (a) When operating a vehicle on the public lands, no person shall exceed posted speed limits, willfully...

  10. 43 CFR 8365.1-3 - Vehicles.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Vehicles. 8365.1-3 Section 8365.1-3 Public... OF THE INTERIOR RECREATION PROGRAMS VISITOR SERVICES Rules of Conduct § 8365.1-3 Vehicles. (a) When operating a vehicle on the public lands, no person shall exceed posted speed limits, willfully...

  11. 43 CFR 8365.1-3 - Vehicles.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Vehicles. 8365.1-3 Section 8365.1-3 Public... OF THE INTERIOR RECREATION PROGRAMS VISITOR SERVICES Rules of Conduct § 8365.1-3 Vehicles. (a) When operating a vehicle on the public lands, no person shall exceed posted speed limits, willfully...

  12. 43 CFR 8365.1-3 - Vehicles.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Vehicles. 8365.1-3 Section 8365.1-3 Public... OF THE INTERIOR RECREATION PROGRAMS VISITOR SERVICES Rules of Conduct § 8365.1-3 Vehicles. (a) When operating a vehicle on the public lands, no person shall exceed posted speed limits, willfully...

  13. π-Stacked structure of thiadiazolo-fused benzotriazinyl radical: Crystal structure and magnetic properties

    NASA Astrophysics Data System (ADS)

    Miura, Youhei; Yoshioka, Naoki

    2015-04-01

    A novel benzotriazinyl radical with a 2,1,3-thiadiazolo fused ring (1,3-diphenyl-1,2-dihydro-[1,2,5]thiadiazolo[3‧,4‧:3,4]benzo[1,2-e]-1,2,4-triazine-2-yl; NSNBT) was prepared and characterized by ESR measurement, cyclic voltammetry, and X-ray crystallographic analysis. By a detailed study of bond lengths and angles, it was found that the molecular structure of NSNBT borrows characteristics both from 2,1,3-benzothiadiazole and from the unsubstituted benzotriazinyl radical, and the central phenyl ring presents a phenanthrene-type bond alternation. Molecules were shown to be arranged in a π-stacked columnar structure, with columns connected to each other through sulfur-sulfur interactions in the crystal. It exhibited strong antiferromagnetic interactions (J/kB = -434 K) derived from its dimer structure.

  14. 29 CFR 1926.907 - Use of safety fuse.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... destroyed. (f) No fuse shall be capped, or primers made up, in any magazine or near any possible source of ignition. (g) No one shall be permitted to carry detonators or primers of any kind on his person. (h) The...-called “drop fuse” method of dropping or pushing a primer or any explosive with a lighted fuse...

  15. 29 CFR 1926.907 - Use of safety fuse.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... destroyed. (f) No fuse shall be capped, or primers made up, in any magazine or near any possible source of ignition. (g) No one shall be permitted to carry detonators or primers of any kind on his person. (h) The...-called “drop fuse” method of dropping or pushing a primer or any explosive with a lighted fuse...

  16. Can Shells be Biomonitor of Contaminants in the Environment: an Investigation Study of Perfluorinated Compounds in Bivalve Shells of China

    NASA Astrophysics Data System (ADS)

    Wang, Lei

    2010-05-01

    To assess the feasibility of using biominerals to biomonitor the extent of persistent contaminants in the environment, concentrations of perfluorinated compounds (PFCs), including perfluorinated carboxylic acids (PFCAs) and perfluorinated alkylsulfonates (PFASs), in the bivalve shells of clams, razor clams, oysters and mussels sampled from 8 sampling sites along China coast were analyzed. Concentrations of these contaminants in the waters and sediments of the sampling sites, as well as in the soft tissues of clams were also determined. Results show that though the concentrations of most PFCs in shells were lower than in soft tissues, the amount of contaminants in shells and soft tissues of bivalves are comparable, due to the larger dry-weight of shells than soft tissues of these animals. Concentrations of some PFCs in shells primarily correlate to concentrations in sediments, while concentrations in the soft tissues seems to be more related to those in water samples. We suggested that shells uptake PFCs by adsorption or passive deposition of the target chemicals to the shell organic matrix followed by a biomineralisation process. Therefore, contaminants bound to the organic matrix in the shell microstructure are sequestrated and hard to release. Like soft tissues, biominerals, e.g. shells, might also be considered as biomonitoring matrix for some contaminants in environments, because (i) the individual differences of contaminants concentrations among shell samples were smaller than soft tissue samples; (ii) secondary pollution is less likely to affect shell samples during sampling and transportation; and (iii) the shells was hypothesized to "record" past exposure to contaminants according to their annual growth ring. (This study was supported by National Science Foundation for Natural Science, China (No. 20807024) & Research Fund for the Doctoral Program of Higher Education of China (No. 200800551051))

  17. Structure-dependent binding and activation of perfluorinated compounds on human peroxisome proliferator-activated receptor γ

    SciTech Connect

    Zhang, Lianying; Ren, Xiao-Min; Wan, Bin; Guo, Liang-Hong

    2014-09-15

    Perfluorinated compounds (PFCs) have been shown to disrupt lipid metabolism and even induce cancer in rodents through activation of peroxisome proliferator-activated receptors (PPARs). Lines of evidence showed that PPARα was activated by PFCs. However, the information on the binding interactions between PPARγ and PFCs and subsequent alteration of PPARγ activity is still limited and sometimes inconsistent. In the present study, in vitro binding of 16 PFCs to human PPARγ ligand binding domain (hPPARγ-LBD) and their activity on the receptor in cells were investigated. The results showed that the binding affinity was strongly dependent on their carbon number and functional group. For the eleven perfluorinated carboxylic acids (PFCAs), the binding affinity increased with their carbon number from 4 to 11, and then decreased slightly. The binding affinity of the three perfluorinated sulfonic acids (PFSAs) was stronger than their PFCA counterparts. No binding was detected for the two fluorotelomer alcohols (FTOHs). Circular dichroim spectroscopy showed that PFC binding induced distinctive structural change of the receptor. In dual luciferase reporter assays using transiently transfected Hep G2 cells, PFCs acted as hPPARγ agonists, and their potency correlated with their binding affinity with hPPARγ-LBD. Molecular docking showed that PFCs with different chain length bind with the receptor in different geometry, which may contribute to their differences in binding affinity and transcriptional activity. - Highlights: • Binding affinity between PFCs and PPARγ was evaluated for the first time. • The binding strength was dependent on fluorinated carbon chain and functional group. • PFC binding induced distinctive structural change of the receptor. • PFCs could act as hPPARγ agonists in Hep G2 cells.

  18. Synthesis and characterization of perfluorinated sulfonimide copolymers as polymer electrolyte membranes

    NASA Astrophysics Data System (ADS)

    Zhou, Shuang

    Ionomers for polymer electrolyte membranes in fuel cell applications were developed utilizing the acidic bis(perfluoromethyl sulfonyl) imide functional group. Perfluorinated vinyl ether sulfonimide monomers CF2=CFOCF 2CF(CF3)O(CF2)2SO2N(Na)SO 2CF3 (1), CF2=CFOCF2CF(CF 3)O(CF2)2SO2N(Na)SO2(CF 2)4SO2N(Na)CF3 (2), CF 2=CFOCF2CF(CF3)O(CF2)2SO 2N(Na)SO2(CF2)6SO2N(Na)CF 3 (3) and CF2=CFOCF2CF(CF3)O(CF2) 2SO2N(Na)SO2(CF2)2O(CF 2)2SO2N(Na)CF3 (4) were synthesized through multiple steps. The complete coupling reaction between the water sensitive CF3SO 2N(Na)Si(CH3)3 and the bromine-protected Dupont monomer BrCF2CFBrOCF2CF(CF3)O(CF2) 2SO2F is an important step to incorporate the sulfonimide group into the monomer 1. Bis(fluorosulfonyl) perfluoroalkanes FSO2RfSO2F (Rf = -(CF 2)4-, -(CF2)6- and -(CF 2)2O(CF2)2-) were used to introduce multifunctional sulfonimides into monomers 2, 3 and 4. Disulfonyl fluoride compounds were reacted with CF 3SO2N(Na)SiMe3 affording the unsymmetrical sulfonyl fluoride intermediates CF3SO2N(Na)SO2R fSO2F. After the transformation of -SO2F into -SO2N(Na)Si(CH3), the coupling reaction of the silyl compounds with BrCF2CFBrOCF2CF(CF3)O(CF 2)2SO2F followed by debromination gave the final products 2, 3 and 4. Copolymers of the sulfonimide monomers with tetrafluoroethylene (TFE) were produced by semi-batch free-radical emulsion copolymerizations. The perflurinated vinyl ether sulfonimide, TFE, the redox initiator pair (NH4) 2S2O8/NaHSO3, the emulsifier C 7F15COONH4 and the buffer NaH2PO 4/Na2HPO4 were mixed in a stirred Parr autoclave at 10°C. During the copolymerization, TFE pressure and the sulfonimide monomer concentration were kept nearly constant in the reaction system to generate copolymers with acidic groups randomly distributed in the polymer chains. Copolymerization conditions were optimized through variations of some important reaction parameters such as the initiator concentration, TFE pressure, the sulfonimide monomer concentration and the

  19. Review on the occurrence, fate and removal of perfluorinated compounds during wastewater treatment.

    PubMed

    Arvaniti, Olga S; Stasinakis, Athanasios S

    2015-08-15

    Perfluorinated compounds (PFCs) consist of a fully fluorinated hydrophobic alkyl chain attached to a hydrophilic end group. Due to their wide use in several industrial and household applications, they have been detected in numerous Sewage Treatment Plants (STPs) during the last ten years. The present review reports the occurrence of 22 PFCs (C4-C14, C16, C18 carboxylates; C4-C8 and C10 sulfonates; 3 sulfonamides) in municipal or/and industrial wastewater, originating from 24 monitoring studies. PFCs levels in sewage sludge have also been reported using data from 12 studies. Most of the above monitoring data originate from the USA, North Europe and Asia and concern perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA), while limited information is available from Mediterranean area, Canada and Australia. PFCs concentrations range up to some hundreds ng/L and some thousands ng/g dry weight in raw wastewater and sludge, respectively. They are not significantly removed during secondary biological treatment, while their concentrations in treated wastewater are often higher compared to raw sewage. Their biodegradation during wastewater treatment does not seem possible; whereas some recent studies have noted the potential transformation of precursor compounds to PFCs during biological wastewater treatment. PFCs sorption onto sludge has been studied in depth and seems to be an important mechanism governing their removal in STPs. Concerning tertiary treatment technologies, significant PFCs removal has been observed using activated carbon, nanofiltration, reverse osmosis or applying advanced oxidation and reduction processes. Most of these studies have been conducted using pure water, while in many cases the experiments have been performed under extreme laboratory conditions (high concentrations, high radiation source, temperature or pressure). Future efforts should be focused on better understanding of biotransformation processes occurred in aerobic and anaerobic

  20. Levels of chlorinated, brominated, and perfluorinated contaminants in birds of prey spanning multiple trophic levels.

    PubMed

    Yordy, Jennifer E; Rossman, Sam; Ostrom, Peggy H; Reiner, Jessica L; Bargnesi, Keely; Hughes, Stacy; Elliot, James D

    2013-04-01

    Birds of prey occupy high trophic levels and can consequently bioaccumulate high levels of environmental contaminants. To evaluate exposure to past- and current-use pollutants, we measured legacy contaminants (i.e., polychlorinated biphenyls [PCBs]; organochlorine pesticides, e.g., DDT), contaminants of emerging concern (polybrominated diphenyl ethers [PBDEs]; perfluorinated compounds [PFCs]), and stable isotopes (δ(13)C, δ(15)N) in 26 birds of prey (10 species) from coastal South Carolina (USA) sampled in 2009 and 2010. Nitrogen isotope ratios (δ(15)N) ranged from 5.2% to 13.7%, indicating the birds of prey spanned two to three trophic levels. Legacy contaminant levels were highly variable but generally comparable to levels reported previously for birds of prey in the southeast US, suggesting exposure has not declined substantially over the past 40 yr. Despite their status as newly emerging environmental contaminants, PFC levels were within the same order of magnitude as legacy contaminants. Although PBDEs were less prevalent, levels were among the greatest observed in wildlife to date (∑PBDEs max. 200 μg/g lipid). Relative contaminant profiles also varied between birds of prey utilizing low and high trophic levels; specifically PFCs contributed to a larger proportion of the contaminant burden in birds utilizing high trophic levels, whereas the legacy pesticide mirex was a larger contributor in low-trophic-level birds, indicating that relative exposure is in part dependent on foraging ecology. This study demonstrates that birds of prey continue to face exposure to legacy contaminants as well as newly emerging contaminants at levels of concern.

  1. Perfluorinated compounds (PFCs) in the atmosphere of Shenzhen, China: Spatial distribution, sources and health risk assessment.

    PubMed

    Liu, Baolin; Zhang, Hong; Yao, Dan; Li, Juying; Xie, Liuwei; Wang, Xinxuan; Wang, Yanping; Liu, Guoqing; Yang, Bo

    2015-11-01

    This study investigated the occurrence of perfluorinated compounds (PFCs) in the atmosphere of Shenzhen, China. 11 PFCs, including two perfluoroalkyl sulfonic acids (PFSAs, C6 and C8) and perfluoroalkyl carboxylic acids (PFCAs, C4-12) were determined by high performance liquid chromatography-negative electrospray ionization-tandem mass spectrometry (HPLC/ESI-MS/MS). Total PFC concentrations (∑ PFCs) in the atmospheric samples ranged from 3.4 to 34 pg m(-3) with an average of 15 pg m(-3). Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were the two most abundant PFCs and on average accounted for 35% and 22% of ∑ PFCs, respectively. ∑ PFCs and total PFCA concentrations (∑ PFCAs) showed a tendency of low-lying East West, while the distribution of total PFSA concentrations (∑ PFSAs) was uniform. Higher concentrations of ∑ PFCs were found in Bao'an District which had very well-developed manufacturing industries. PCA model was employed to quantitatively calculate the contributions of sources. The results showed that PFOA-factor, long chain PFCs-factor and PFOS-factor were the three main source categories for PFCs in the atmosphere. Meanwhile, long-distance transport of pollutants from southeastern coastal areas might be another source of PFCs in Shenzhen atmosphere. PFCs in the atmosphere were more positively correlated with the levels PM10 than PM2.5, which indicated PFCs were more likely to adhere to particles with relatively large sizes. The hazard ratios of noncancer risk through breathing based on PFOS and PFOA concentrations were calculated and were less than unity, suggesting that PFCs concentrations may pose no or immediate threat to the residents in Shenzhen.

  2. Determination of perfluorinated compounds (PFCs) in various foodstuff packaging materials used in the Greek market.

    PubMed

    Zafeiraki, Effrosyni; Costopoulou, Danae; Vassiliadou, Irene; Bakeas, Evangelos; Leondiadis, Leondios

    2014-01-01

    Perfluorinated compounds (PFCs) are used in food packaging materials as coatings/additives for oil and moisture resistance. In the current study, foodstuff-packaging materials collected from the Greek market, made of paper, paperboard or aluminum foil were analyzed for the determination of PFCs. For the analysis of the samples, pressurized liquid extraction (PLE), liquid chromatography–tandem mass spectrometry (LC–MS/MS) and isotope dilution method were applied to develop a specific and sensitive method of analysis for the quantification of 12 PFCs: perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoA), perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS) and perfluorooctane sulfonate (PFOS) and the qualitative detection of 5 more: perfluorotridecanoic acid (PFTrDA), perfluorotetradecanoic acid (PFTeDA), perflyohexadecanoic acid (PFHxDA), perfluorooctadecanoic acid (PFODA) and perfluorodecane sulfonate (PFDS). No PFCs were quantified in aluminum foil wrappers, baking paper materials or beverage cups. PFTrDA, PFTeDA and PFHxDA were detected in fast food boxes. In the ice cream cup sample only PFHxA was found. On the other hand, several PFCs were quantified and detected in fast food wrappers, while the highest levels of PFCs were found in the microwave popcorn bag. PFOA and PFOS were not detected in any of the samples. Compared to other studies from different countries, very low concentrations of PFCs were detected in the packaging materials analyzed. Our results suggest that probably no serious danger for consumers’ health can be associated with PFCs contamination of packaging materials used in Greece.

  3. Terrestrial Sources of Perfluorinated Gases: Excess CF4 and SF6 in Mojave Desert Groundwaters

    NASA Astrophysics Data System (ADS)

    Deeds, D. A.; Vollmer, M. K.; Kulongoski, J. T.; Miller, B. R.; Hilton, D. R.; Izbicki, J. A.; Harth, C. M.; Weiss, R. F.

    2004-12-01

    The recent discovery of perfluorinated gases in fluid inclusions of granites and fluorites suggests a geologic source for the estimated 40 parts-per-trillion (ppt) of tetrafluoromethane (CF4) and <0.006 ppt of sulfur hexafluoride (SF6) in the preindustrial atmosphere. The accumulation of these gases in groundwaters with long residence times enables the detection of even small emissions from the surrounding aquifer material. We have measured high concentrations of CF4 and SF6 in groundwaters from the Mojave Desert, California. Dissolved SF6 was extracted by a purge and trap technique and analyzed by gas chromatography with electron capture detection. Dissolved CF4 was sampled by headspace extraction, using liquid helium to cryofocus the analytes prior to injection into the Medusa gas chromatograph/quadrupole mass spectrometer analytical system. Current precisions and accuracies for these measurements are on the order of 2% for both gases. Initial measurements of dissolved CF4 concentrations range from ˜0.05 to ˜1.5 pmol kg-1, about 5 to 15 times higher than expected for water in equilibrium with the preindustrial atmosphere at the local temperature and altitude of the recharge site. SF6 concentrations range from ˜0.3 to ˜16 fmol kg-1, up to several thousand times higher than expected for air-saturated water. Taking into account the large uncertainties in the estimated preindustrial atmospheric concentration of SF6, and in the estimated atmospheric lifetimes of both SF6 and CF4, the ratio of their excess abundances in Mojave Desert groundwaters agrees within an order of magnitude with the estimated ratio of natural fluxes required to sustain their preindustrial atmospheric concentrations. Relationships among dissolved CF4 and SF6 concentrations and the other geochemical properties of the aquifer, including groundwater residence times (ages), helium abundances and isotopic ratios, and fluoride concentrations will be presented.

  4. Biomonitoring of Perfluorinated Compounds in Children and Adults Exposed to Perfluorooctanoate-Contaminated Drinking Water

    PubMed Central

    Hölzer, Jürgen; Midasch, Oliver; Rauchfuss, Knut; Kraft, Martin; Reupert, Rolf; Angerer, Jürgen; Kleeschulte, Peter; Marschall, Nina; Wilhelm, Michael

    2008-01-01

    Objective 40,000 residents in Arnsberg, Germany, had been exposed to drinking water contaminated with perfluorinated compounds (PFCs). Internal exposure of the residents of Arnsberg to six PFCs was assessed in comparison with reference areas. Design and participants One hundred seventy children (5–6 years of age), 317 mothers (23–49 years), and 204 men (18–69 years) took part in the cross-sectional study. Measurements Individual consumption of drinking water and personal characteristics were assessed by questionnaire and interview. Perfluorooctanoate (PFOA), perfluorooctanesulfonate (PFOS), perfluorohexanoate, perfluorohexanesulfonate (PFHxS), perfluoropentanoate, and perfluorobutanesulfonate (PFBS) in blood plasma and PFOA/PFOS in drinking water samples were measured by solid-phase extraction, high-performance liquid chromatrography, and tandem mass spectrometry detection. Results Of the various PFCs, PFOA was the main compound found in drinking water (500–640 ng/L). PFOA levels in blood plasma of residents living in Arnsberg were 4.5–8.3 times higher than those for the reference population (arithmetic means Arnsberg/controls: children 24.6/5.2 μg/L, mothers 26.7/3.2 μg/L, men 28.5/6.4 μg/L). Consumption of tap water at home was a significant predictor of PFOA blood concentrations in Arnsberg. PFHxS concentrations were significantly increased in Arnsberg compared with controls (p < 0.05). PFBS was detected in 33% of the children, 4% of the women, and 13% of the men in Arnsberg compared with 5%, 0.7%, and 3%, respectively, in the reference areas (p < 0.05). Regression analysis showed that age and male sex were significant predictors of PFOS, PFOA, and PFHxS; associations of other regressors (diet, body mass index) varied among PFCs. Conclusions PFC concentrations in blood plasma of children and adults exposed to PFC-contaminated drinking water were increased 4- to 8-fold compared with controls. PMID:18470314

  5. Perfluorinated acids as novel chemical tracers of global circulation of ocean waters.

    PubMed

    Yamashita, Nobuyoshi; Taniyasu, Sachi; Petrick, Gert; Wei, Si; Gamo, Toshitaka; Lam, Paul K S; Kannan, Kurunthachalam

    2008-01-01

    Perfluorinated acids (PFAs) such as perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) are global environmental contaminants. The physicochemical properties of PFAs are unique in that they have high water solubilities despite the low reactivity of carbon-fluorine bond, which also imparts high stability in the environment. Because of the high water solubilities, the open-ocean water column is suggested to be the final sink for PFOS and PFOA. However, little is known on the distribution of PFAs in the oceans around the world. Here we describe the horizontal (spatial) and vertical distribution of PFAs in ocean waters worldwide. PFOS and PFOA concentrations in the North Atlantic Ocean ranged from 8.6 to 36pg l(-1) and from 52 to 338pg l(-1), respectively, whereas the corresponding concentrations in the Mid Atlantic Ocean were 13-73pg l(-1) and 67-439pg l(-1). These were completely different from the surface waters of the South Pacific Ocean and the Indian Ocean (overall range of <5-11pg l(-1) for PFOS and PFOA). Vertical profiles of PFAs in the marine water column were associated with the global ocean circulation theory. Vertical profiles of PFAs in water columns from the Labrador Sea reflected the influx of the North Atlantic Current in surface waters, the Labrador Current in subsurface waters, and the Denmark Strait Overflow Water in deep layers below 2000m. Striking differences in the vertical and spatial distribution of PFAs, depending on the oceans, suggest that these persistent acids can serve as useful chemical tracers to allow us to study oceanic transportation by major water currents. The results provide evidence that PFA concentrations and profiles in the oceans adhere to a pattern consistent with the global "Broecker's Conveyor Belt" theory of open ocean water circulation.

  6. Metabolical shifts towards alternative BTEX biodegradation intermediates induced by perfluorinated compounds in firefighting foams.

    PubMed

    Montagnolli, Renato Nallin; Lopes, Paulo Renato Matos; Cruz, Jaqueline Matos; Claro, Marina Turini; Quiterio, Gabriela Mercuri; Bidoia, Ederio Dino

    2017-04-01

    The type and concentration of perfluorinated compounds (PFCs) can induce different types of enzymes and promote alternate patterns of BTEX transformation. However, it is not known how the presence of active fluorocarbon-degrading microbial populations affects the transformation of BTEX. In addition to chemical analysis at the molecular level, our research approached the aqueous film forming fire-fighting foams (AFFF) and BTEX co-contamination at a large-scale with respirometers to quantify the total microbial metabolism of soil via CO2 output levels. The intended outcome of this research was to obtain and characterize shifts in BTEX degradation at a set realistic environmental condition while measuring byproducts and CO2 production. Both methodologies complimentarily provided an in-depth knowledge of the environmental behavior of fire-fighting foams. The biodegradation was monitored using headspace sampling and two types of gas chromatography: thermal conductivity detector and flame ionization detector. Headspace samples were periodically withdrawn for BTEX biodegradation and CO2 production analysis. Our research suggests the discovery of an altered metabolic pathway in aromatic hydrocarbons biodegradation that is directly affected by fluorinated substances. The fluorinated compounds affected the BTEX biodegradation kinetics, as PFCs may contribute to a shift in styrene and catechol concentrations in co-contamination scenarios. A faster production of styrene and catechol was detected. Catechol is also rapidly consumed, thus undergoing further metabolic stages earlier under the presence of PFCs. The release of AFFF compounds not only changes byproducts output but also drastically disturbs the soil microbiota according to the highly variable CO2 yields. Therefore, we observed a high sensitivity of microbial consortia due to PFCs in the AFFF formulation, therefore shifting their BTEX degradation routes in terms of intermediate products concentration.

  7. Determination of ten perfluorinated compounds in bluegill sunfish (Lepomis macrochirus) fillets

    SciTech Connect

    Delinsky, Amy D.; Strynar, Mark J.; Nakayama, Shoji F.; Varns, Jerry L.; Ye, XiBiao; McCann, Patricia J.; Lindstrom, Andrew B.

    2009-11-15

    A rigorous solid phase extraction/liquid chromatography/tandem mass spectrometry method for the measurement of 10 perfluorinated compounds (PFCs) in fish fillets is described and applied to fillets of bluegill sunfish (Lepomis macrochirus) collected from selected areas of Minnesota and North Carolina. The 4 PFC analytes routinely detected in bluegill fillets were perfluorooctane sulfonate (PFOS), perfluorodecanoic acid (C10), perfluoroundecanoic acid (C11), and perflurododecanoic acid (C12). Measures of method accuracy and precision for these compounds showed that calculated concentrations of PFCs in spiked samples differed by less than 20% from their theoretical values and that the %RSD for repeated measurements was less than 20%. Minnesota samples were collected from areas of the Mississippi River near historical PFC sources, from the St. Croix River as a background site, and from Lake Calhoun, which has no documented PFC sources. PFOS was the most prevalent PFC found in the Minnesota samples, with median concentrations of 47.0-102 ng/g at locations along the Mississippi River, 2.08 ng/g in the St. Croix River, and 275 ng/g in Lake Calhoun. North Carolina samples were collected from two rivers with no known historical PFC sources. PFOS was the predominant analyte in fish taken from the Haw and Deep Rivers, with median concentrations of 30.3 and 62.2 ng/g, respectively. Concentrations of C10, C11, and C12 in NC samples were among the highest reported in the literature, with respective median values of 9.08, 23.9, and 6.60 ng/g in fish from the Haw River and 2.90, 9.15, and 3.46 ng/g in fish from the Deep River. These results suggest that PFC contamination in freshwater fish may not be limited to areas with known historical PFC inputs.

  8. In vitro evaluation of the immunotoxic potential of perfluorinated compounds (PFCs).

    PubMed

    Corsini, Emanuela; Avogadro, Anna; Galbiati, Valentina; dell'Agli, Mario; Marinovich, Marina; Galli, Corrado L; Germolec, Dori R

    2011-01-15

    There is evidence from both epidemiology and laboratory studies that perfluorinated compounds may be immunotoxic, affecting both cell-mediated and humoral immunity. The overall goal of this study was to investigate the mechanisms underlying the immunotoxic effects of perfluorooctane sulfonate (PFOS) and perfluorooctane acid (PFOA), using in vitro assays. The release of the pro-inflammatory cytokines IL-6, IL-8, and TNF-α was evaluated in lipolysaccharide (LPS)-stimulated human peripheral blood leukocytes and in the human promyelocytic cell line THP-1, while the release of IL-4, IL-10 and IFN-γ was evaluated in phytohaemagglutinin (PHA)-stimulated peripheral blood leukocytes. PFOA and PFOS suppressed LPS-induced TNF-α production in primary human cultures and THP-1 cells, while IL-8 was suppressed only in THP-1 cells. IL-6 release was decreased only by PFOS. Both PFOA and PFOS decreased T-cell derived, PHA-induced IL-4 and IL-10 release, while IFN-γ release was affected only by PFOS. In all instances, PFOS was more potent than PFOA. Mechanistic investigations carried out in THP-1 cells demonstrated that the effect on cytokine release was pre-transcriptional, as assessed by a reduction in LPS-induced TNF-α mRNA expression. Using siRNA, a role for PPAR-α could be demonstrated for PFOA-induced immunotoxicity, while an inhibitory effect on LPS-induced I-κB degradation could explain the immunomodulatory effect of PFOS. The dissimilar role of PPAR-α in PFOA and PFOS-induced immunotoxicity was consistent with the differing effects observed on LPS-induced MMP-9 release: PFOA, as the PPAR-α agonist fenofibrate, modulated the release, while PFOS had no effect. Overall, these studies suggest that PFCs directly suppress cytokine secretion by immune cells, and that PFOA and PFOS have different mechanisms of action.

  9. In vitro evaluation of the immunotoxic potential of perfluorinated compounds (PFCs)

    SciTech Connect

    Corsini, Emanuela; Avogadro, Anna; Galbiati, Valentina; Dell'Agli, Mario; Marinovich, Marina; Galli, Corrado L.; Germolec, Dori R.

    2011-01-15

    There is evidence from both epidemiology and laboratory studies that perfluorinated compounds may be immunotoxic, affecting both cell-mediated and humoral immunity. The overall goal of this study was to investigate the mechanisms underlying the immunotoxic effects of perfluorooctane sulfonate (PFOS) and perfluorooctane acid (PFOA), using in vitro assays. The release of the pro-inflammatory cytokines IL-6, IL-8, and TNF-{alpha} was evaluated in lipolysaccharide (LPS)-stimulated human peripheral blood leukocytes and in the human promyelocytic cell line THP-1, while the release of IL-4, IL-10 and IFN-{gamma} was evaluated in phytohaemagglutinin (PHA)-stimulated peripheral blood leukocytes. PFOA and PFOS suppressed LPS-induced TNF-{alpha} production in primary human cultures and THP-1 cells, while IL-8 was suppressed only in THP-1 cells. IL-6 release was decreased only by PFOS. Both PFOA and PFOS decreased T-cell derived, PHA-induced IL-4 and IL-10 release, while IFN-{gamma} release was affected only by PFOS. In all instances, PFOS was more potent than PFOA. Mechanistic investigations carried out in THP-1 cells demonstrated that the effect on cytokine release was pre-transcriptional, as assessed by a reduction in LPS-induced TNF-{alpha} mRNA expression. Using siRNA, a role for PPAR-{alpha} could be demonstrated for PFOA-induced immunotoxicity, while an inhibitory effect on LPS-induced I-{kappa}B degradation could explain the immunomodulatory effect of PFOS. The dissimilar role of PPAR-{alpha} in PFOA and PFOS-induced immunotoxicity was consistent with the differing effects observed on LPS-induced MMP-9 release: PFOA, as the PPAR-{alpha} agonist fenofibrate, modulated the release, while PFOS had no effect. Overall, these studies suggest that PFCs directly suppress cytokine secretion by immune cells, and that PFOA and PFOS have different mechanisms of action.

  10. Perfluorinated alkylated substances in the aquatic environment: an Austrian case study.

    PubMed

    Clara, M; Gans, O; Weiss, S; Sanz-Escribano, D; Scharf, S; Scheffknecht, C

    2009-10-01

    Perfluorinated alkylated substances (PFAS) are of global interest due to their occurrence and persistency in the environment. This study includes surface waters and sediments for the analysis of eleven PFAS. The PFAS studied can be grouped in perfluoroalkyl carboxylates (PFCAs), perfluoroalkyl sulfonates (PFS) and perfluoroalkyl sulfonamides (PFSA). The two most important compounds are perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS). These two substances showed the most significant values for surface water samples with maximum concentrations of 21 ng l(-1) for PFOA and 37 ng l(-1) for PFOS. Sediment samples from seven Austrian lakes and the river Danube were studied. Whereas PFSA and PFS were not detected in any sediment sample PFCAs were detected in most of the lake samples in concentrations up to 1.7 microg kg(-1) dry wt. PFOA, perfluorohexanoic acid (PFHxA) and perfluoroheptanoic acid (PFHpA) were detected in all Danube river sediment samples in concentrations varying from 0.1 up to 5.1 microg kg(-1) dry wt. For the various sampling points the proportional mass flows deriving from wastewater discharges were calculated. Whereas only up to 10% of the average flow is discharged wastewater up to more than 50% of the PFAS mass flows in the rivers can be attributed to wastewater discharges. Besides wastewater different other pathways as emissions from point sources, further degradation of precursor products, runoff from contaminated sites or surface runoff as well as dry and wet deposition have to be considered as relevant sources for PFAS contamination in surface waters.

  11. Skipjack tuna as a bioindicator of contamination by perfluorinated compounds in the oceans.

    PubMed

    Hart, Kimberly; Kannan, Kurunthachalam; Tao, Lin; Takahashi, Shin; Tanabe, Shinsuke

    2008-09-15

    Perfluorinated chemicals (PFCs) have emerged as global environmental contaminants. Studies have reported the widespread occurrence of PFCs in biota from marine coastal waters and in remote polar regions. However, few studies have reported the distribution of PFCs in biota from offshore waters and open oceans. In this study, concentrations of nine PFCs were determined in the livers of 60 skipjack tuna (Katsuwonus pelamis) collected from offshore waters and the open ocean along the Pacific Rim, including the Sea of Japan, the East China Sea, the Indian Ocean, and the Western North Pacific Ocean, during 1997-1999. At least one of the nine PFCs was found in every tuna sample analyzed. Overall, perfluorooctanesulfonate (PFOS) and perfluoroundecanoic acid (PFUnDA) were the predominant compounds found in livers of tuna at concentrations of <1-58.9 and <1-31.6 ng/g, wet wt, respectively. Long-chain perfluorocarboxylates such as perfluorodecanoic acid (PFDA) and perfluorododecanoic acid (PFDoDA) were common in the tuna livers. In livers of tuna from several offshore and open-ocean locations, concentrations of PFUnDA were greater than the concentrations of PFOS. The profiles and concentrations of PFCs in tuna livers suggest that the sources in East Asia are dominated by long-chain perfluorocarboxylates, especially PFUnDA. High concentrations of PFUnDA in tuna may indicate a shift in sources of PFCs in East Asia. The spatial distribution of PFOS in skipjack tuna reflected the concentrations previously reported in seawater samples from the Pacific and Indian Oceans, suggesting that tuna are good bioindicators of pollution by PFOS. Despite its predominance in ocean waters, PFOA was rarely found in tuna livers, indicative of the low bioaccumulation potential of this compound. Our study establishes baseline concentrations of PFCs in skipjack tuna from the oceans of the Asia-Pacific region, enabling future temporal trend studies of PFCs in oceans.

  12. Genotoxicity of perfluorinated chemicals (PFCs) to the green mussel (Perna viridis).

    PubMed

    Liu, Changhui; Chang, Victor W C; Gin, Karina Y H; Nguyen, Viet Tung

    2014-07-15

    Concerns regarding perfluorinated chemicals (PFCs) have grown significantly in recent years. However, regulations and guidelines regarding the emission and treatment of PFCs are still missing in most parts of the world, mostly due to the lack of PFC toxicity data. In the current study, the genotoxic effects of four common PFCs, named perfluorooctanesulfonate (PFOS), perfluoroocanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were investigated on marine mussels. The effects of exposure time and concentration on the toxic behavior of the compounds were also examined. Genotoxicity of PFCs was assessed in biomarker assays, showing that exposure to the target compounds could damage the organism's genetic material to varying extents, including DNA strand breaks and fragmentation, chromosomal breaks and apoptosis. The adverse effects increased with both exposure concentration and time and were related with the organism burden of PFCs. The integrated biomarker response analysis demonstrated that PFOS exhibited a higher genotoxicity than the other tested compounds. The EC50 values and confidence intervals based on integrative genotoxicity were 33 (29-37), 594 (341-1036), 195 (144-265) and 78 (73-84) μg/L for PFOS, PFOA, PFNA and PFDA respectively, classifying PFOS as a highly genotoxic compound. Although primary DNA damage was shown to be recoverable after exposure ceased, permanent genetic damage caused by elevated PFC concentrations was not restored. This is the first ecotoxicity study of PFCs that focuses on the genotoxic effects of the compounds, clearly indicating the genotoxicity of the tested PFCs and demonstrating that functional groups have a major impact on the compounds' genotoxic behavior.

  13. Perfluorinated compounds in fish from U.S. urban rivers and the Great Lakes.

    PubMed

    Stahl, Leanne L; Snyder, Blaine D; Olsen, Anthony R; Kincaid, Thomas M; Wathen, John B; McCarty, Harry B

    2014-11-15

    Perfluorinated compounds (PFCs) have recently received scientific and regulatory attention due to their broad environmental distribution, persistence, bioaccumulative potential, and toxicity. Studies suggest that fish consumption may be a source of human exposure to perfluorooctane sulfonate (PFOS) or long-chain perfluorocarboxylic acids. Most PFC fish tissue literature focuses on marine fish and waters outside of the United States (U.S.). To broaden assessments in U.S. fish, a characterization of PFCs in freshwater fish was initiated on a national scale using an unequal probability design during the U.S. Environmental Protection Agency's (EPA's) 2008-2009 National Rivers and Streams Assessment (NRSA) and the Great Lakes Human Health Fish Tissue Study component of the 2010 EPA National Coastal Condition Assessment (NCCA/GL). Fish were collected from randomly selected locations--164 urban river sites and 157 nearshore Great Lake sites. The probability design allowed extrapolation to the sampled population of 17,059 km in urban rivers and a nearshore area of 11,091 km(2) in the Great Lakes. Fillets were analyzed for 13 PFCs using high-performance liquid chromatography tandem mass spectrometry. Results showed that PFOS dominated in frequency of occurrence, followed by three other longer-chain PFCs (perfluorodecanoic acid, perfluoroundecanoic acid, and perfluorododecanoic acid). Maximum PFOS concentrations were 127 and 80 ng/g in urban river samples and Great Lakes samples, respectively. The range of NRSA PFOS detections was similar to literature accounts from targeted riverine fish sampling. NCCA/GL PFOS levels were lower than those reported by other Great Lakes researchers, but generally higher than values in targeted inland lake studies. The probability design allowed development of cumulative distribution functions (CDFs) to quantify PFOS concentrations versus the sampled population, and the application of fish consumption advisory guidance to the CDFs resulted in

  14. Perfluorinated alkylated acids in groundwater and drinking water: identification, origin and mobility.

    PubMed

    Eschauzier, Christian; Raat, Klaasjan J; Stuyfzand, Pieter J; De Voogt, Pim

    2013-08-01

    Human exposure to perfluorinated alkylated acids (PFAA) occurs primarily via the dietary intake and drinking water can contribute significantly to the overall PFAA intake. Drinking water is produced from surface water and groundwater. Waste water treatment plants have been identified as the main source for PFAA in surface waters and corresponding drinking water. However, even though groundwater is an important source for drinking water production, PFAA sources remain largely uncertain. In this paper, we identified different direct and indirect sources of PFAA to groundwater within the catchment area of a public supply well field (PSWF) in The Netherlands. Direct sources were landfill leachate and water draining from a nearby military base/urban area. Indirect sources were infiltrated rainwater. Maximum concentrations encountered in groundwater within the landfill leachate plume were 1.8 μg/L of non branched perfluorooctanoic acid (L-PFOA) and 1.2 μg/L of perfluorobutanoic acid (PFBA). Sum concentrations amounted to 4.4 μg/L total PFAA. The maximum concentration of ΣPFAA in the groundwater originating from the military camp was around 17 ng/L. Maximum concentrations measured in the groundwater halfway the landfill and the PWSF (15 years travel distance) were 29 and 160 ng/L for L-PFOA and PFBA, respectively. Concentrations in the groundwater pumping wells (travel distance >25 years) were much lower: 0.96 and 3.5 ng/L for L-PFOA and PFBA, respectively. The chemical signature of these pumping wells corresponded to the signature encountered in other wells sampled which were fed by water that had not been in contact with potential contaminant sources, suggesting a widespread diffuse contamination from atmospheric deposition.

  15. Fused silica challenges in sensitive space applications

    NASA Astrophysics Data System (ADS)

    Criddle, Josephine; Nürnberg, Frank; Sawyer, Robert; Bauer, Peter; Langner, Andreas; Schötz, Gerhard

    2016-07-01

    Space bound as well as earthbound spectroscopy of extra-terrestrial objects finds its challenge in light sources with low intensities. High transmission for every optical element along the light path requires optical materials with outstanding performance to enable the measurement of even a one-photon event. Using the Lunar Laser Ranging Project and the LIGO and VIRGO Gravitational Wave Detectors as examples, the influence of the optical properties of fused silica will be described. The Visible and Infrared Surveillance Telescope for Astronomy (VISTA) points out the material behavior in the NIR regime, where the chemical composition of optical materials changes the performance. Special fibers are often used in combination with optical elements as light guides to the spectroscopic application. In an extended spectral range between 350 and 2,200 nm Heraeus developed STU fiber preforms dedicated for broad band spectroscopy in astronomy. STU fibers in the broad spectral range as well as SSU fibers for UV transmission (180 - 400 nm) show also high gamma radiation resistance which allows space applications.

  16. Novel, Broad Spectrum Anticancer Agents Containing the Tricyclic 5:7:5-Fused Diimidazodiazepine Ring System

    PubMed Central

    2010-01-01

    Synthesis of a series of novel, broad spectrum anticancer agents containing the tricyclic 5:7:5-fused diimidazo[4,5-d:4′,5′-f][1,3]diazepine ring system is reported. Compounds 1, 2, 8, 11, and 12 in the series show promising in vitro antitumor activity with low micromolar IC50 values against prostate, lung, breast, and ovarian cancer cell lines. Some notions about structure−activity relationships and a possible mechanism of biological activity are presented. Also presented are preliminary in vivo toxicity studies of 1 using SCID mice. PMID:21572541

  17. Deuterium Abundance Toward WD2211-495: Results from the Far Ultraviolet Spectroscopic Explorer (FUSE) Mission

    NASA Technical Reports Server (NTRS)

    Hebrard, G.; Lemoine, M.; Vidal-Madjar, A.; Desert, J. M.; LecavelierdesEtangs, A.; Ferlet, R.; Wood, B. E.; Linsky, J. L.; Kruk, J. W.; Chayer, P.; Oegerle, William R. (Technical Monitor)

    2002-01-01

    We present a deuterium abundance analysis of the line of sight toward the white dwarf WD 2211-495 observed with the Far Ultraviolet Spectroscopic Explorer (FUSE). Numerous interstellar lines are detected on the continuum of the stellar spectrum. A thorough analysis was performed through the simultaneous fit of interstellar absorption lines detected in the four FUSE channels of multiple observations with different slits. We excluded all saturated lines in order to reduce possible systematic errors on the column density measurements. We report the determination of the average interstellar D/O and D/N ratios along this line of sight at the 95% confidence level: D/O = 4.0 (+/-1.2) x 10(exp -2); D/N = 4.4 (+/-1.3) x 10(exp -1). In conjunction with FUSE observations of other nearby sight lines, the results of this study will allow a deeper understanding of the present-day abundance of deuterium in the local interstellar medium and its evolution with time.

  18. Automated Driftmeter Fused with Inertial Navigation

    DTIC Science & Technology

    2014-03-27

    DCM direction cosine matrix . . . . . . . . . . . . . . . . . . . . . . . . . 20 RLG ring laser gyro...The cameras had a 1280 × 1024 (1.3 megapixel (MP)) resolution. They were rigidly mounted with space between them, allowing distance for triangulation ...dynamics range. Fortunately, both of these concerns are easily satisfied with today’s ring laser gyro (RLG) or fiber optic gyroscope (FOG) technology

  19. Determination of perfluorinated compounds in packaging materials and textiles using pressurized liquid extraction with gas chromatography-mass spectrometry.

    PubMed

    Lv, Gang; Wang, Libing; Liu, Shaocong; Li, Shufen

    2009-03-01

    A simultaneous determination method of trace amounts of perfluorinated compounds, such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in packaging materials and textiles, has been developed, using pressurized liquid extraction (PLE) with gas chromatography-mass spectrometry (GC/MS). The perfluorinated compounds were primarily extracted from the samples by a PLE procedure, in which the parameters were optimized by response surface methodology. The solvent was then removed by blowing nitrogen and a silylation step was carried out with N,N-bis(trimethylsilyl)trifluoroacetamide. The silylated compounds were identified and quantified by GC/MS. The proposed method was applied to determine the PFOA and PFOS in polytetrafluoroethylene packaging materials and textiles, where the detection limits of the two compounds were 1.6 and 13.9 ng mL(-1), respectively. The results showed that the concentrations of PFOA and PFOS in the packaging materials and textiles ranged from 17.5 to 45.9 and 33.7 to 81.3 ng g(-1), respectively.

  20. Synthesis of per-fluorinated polymer-alloy based on PTFE by high temperature EB-irradiation

    NASA Astrophysics Data System (ADS)

    Oshima, Akihiro; Mutou, Fumihiro; Hyuga, Toshiyuki; Asano, Saneto; Ichizuri, Shogo; Li, Jingye; Miura, Takaharu; Washio, Masakazu

    2005-07-01

    In this study, synthesis of per-fluorinated polymer-alloy based on polytetrafluoroethylene (PTFE) has been demonstrated by high temperature irradiation techniques. The per-fluorinated polymer-blend thin films originated from polymer dispersion (PTFE, PTFE/PFA polymer-blend: FA and PTFE/FEP polymer-blend: FE) have been fabricated by the wire-bar coating equipment. The obtained films (thickness: 5-15 μm) were irradiated by EB at 335 °C ± 5 °C in nitrogen gas atmosphere. Characterization of irradiated polymer-blends has been performed by 19F solid-state NMR spectroscopy, thermal analysis and so on. By DSC analysis, the heat of crystallization (ΔHc) of both irradiated polymer-blends were decreased with increase in absorbed dose. Moreover, the melting and crystallization temperatures of both materials shift to lower temperatures, compared with crosslinked PTFE. The obtained materials showed the lower crystallinity. By 19F solid-state NMR spectroscopy, the new signals appeared at around -160 ppm and at -188 ppm. The signals are assigned to the fluorine signals of CF groups, which represent crosslinking sites with Y-type (>CF-) and Y‧-type (>Cdbnd CF-) in the polymer-blend chains. Thus, it is confirmed that the polymer-alloys with good performance based on PTFE are synthesized through the radiation crosslinking reaction between PTFE and PFA or FEP molecules.

  1. Organic-inorganic hybrid fluorous monolithic capillary column for selective solid-phase microextraction of perfluorinated persistent organic pollutants.

    PubMed

    Xiong, Xiyue; Yang, Zihui; Huang, Yongbin; Jiang, Linbo; Chen, Yingzhuang; Shen, Yao; Chen, Bo

    2013-03-01

    A novel construction strategy of monolithic capillary column for selectively enriching perfluorinated persistent organic pollutants was proposed. The organic-inorganic hybrid fluorous monolithic capillary column was synthesized by a "one-pot" approach via the polycondensation of γ-methacryloxypropyltrimethoxy-silane, then in situ copolymerization of 1H,1H,7H-dodecafluoroheptyl methacrylate and vinyl group on the precondensed siloxanes. The obtained monolithic columns were systematically characterized. The results demonstrated that the optimal column possessed good mechanical stability and high permeability. The adsorption capacities of the optimized monolithic column for perfluorooctanoic acid and perfluorooctane sulfonate were 0.257 and 0.513 μg/mg, respectively. Adsorption capacities of the monoliths were proved to increasing with increasing the amounts of fluorinated monomers in the fluorous monoliths. Sodium 1-octanesulfonate, as a comparison compound, was hardly adsorbed on the fluorous monolith. In addition, the trace amounts of perfluorooctanoic acid and perfluorooctane sulfonate in water samples can be successfully concentrated about 160 times to their original concentrations by this monolithic column. These results demonstrated that the capacity and selectivity of the affinity fluorous column is high and can be applied to the selective enrichment for the perfluorinated persistent organic pollutants from environmental samples.

  2. Perfluorinated chemicals in surface waters and sediments from northwest Georgia, USA, and their bioaccumulation in Lumbriculus variegatus

    USGS Publications Warehouse

    Lasier, Peter J.; Washington, John W.; Hassan, Sayed M.; Jenkins, Thomas M.

    2011-01-01

    Concentrations of perfluorinated chemicals (PFCs) were measured in surface waters and sediments from the Coosa River watershed in northwest Georgia, USA, to examine their distribution downstream of a suspected source. Samples from eight sites were analyzed using liquid chromatography-tandem mass spectrometry. Sediments were also used in 28-d exposures with the aquatic oligochaete, Lumbriculus variegatus, to assess PFC bioaccumulation. Concentrations of PFCs in surface waters and sediments increased significantly below a land-application site (LAS) of municipal/industrial wastewater and were further elevated by unknown sources downstream. Perfluorinated carboxylic acids (PFCAs) with eight or fewer carbons were the most prominent in surface waters. Those with 10 or more carbons predominated sediment and tissue samples. Perfluorooctane sulfonate (PFOS) was the major homolog in contaminated sediments and tissues. This pattern among sediment PFC concentrations was consistent among sites and reflected homolog concentrations emanating from the LAS. Concentrations of PFCs in oligochaete tissues revealed patterns similar to those observed in the respective sediments. The tendency to bioaccumulate increased with PFCA chain length and the presence of the sulfonate moiety. Biota-sediment accumulation factors indicated that short-chain PFCAs with fewer than seven carbons may be environmentally benign alternatives in aquatic ecosystems; however, sulfonates with four to seven carbons may be as likely to bioaccumulate as PFOS.

  3. Perfluorinated chemicals in surface waters and sediments from northwest Georgia, USA, and their bioaccumulation in Lumbriculus variegatus.

    PubMed

    Lasier, Peter J; Washington, John W; Hassan, Sayed M; Jenkins, Thomas M

    2011-10-01

    Concentrations of perfluorinated chemicals (PFCs) were measured in surface waters and sediments from the Coosa River watershed in northwest Georgia, USA, to examine their distribution downstream of a suspected source. Samples from eight sites were analyzed using liquid chromatography-tandem mass spectrometry. Sediments were also used in 28-d exposures with the aquatic oligochaete, Lumbriculus variegatus, to assess PFC bioaccumulation. Concentrations of PFCs in surface waters and sediments increased significantly below a land-application site (LAS) of municipal/industrial wastewater and were further elevated by unknown sources downstream. Perfluorinated carboxylic acids (PFCAs) with eight or fewer carbons were the most prominent in surface waters. Those with 10 or more carbons predominated sediment and tissue samples. Perfluorooctane sulfonate (PFOS) was the major homolog in contaminated sediments and tissues. This pattern among sediment PFC concentrations was consistent among sites and reflected homolog concentrations emanating from the LAS. Concentrations of PFCs in oligochaete tissues revealed patterns similar to those observed in the respective sediments. The tendency to bioaccumulate increased with PFCA chain length and the presence of the sulfonate moiety. Biota-sediment accumulation factors indicated that short-chain PFCAs with fewer than seven carbons may be environmentally benign alternatives in aquatic ecosystems; however, sulfonates with four to seven carbons may be as likely to bioaccumulate as PFOS.

  4. Levels of perfluorinated acids (PFCAs) in different tissues of Lepidochelys olivacea sea turtles from the Escobilla beach (Oaxaca, Mexico).

    PubMed

    Pasanisi, Eugenia; Cortés-Gómez, Adriana A; Pérez-López, Marcos; Soler, Francisco; Hernández-Moreno, David; Guerranti, Cristiana; Martellini, Tania; Fuentes-Mascorro, Gisela; Romero, Diego; Cincinelli, Alessandra

    2016-12-01

    Lepidochelys olivacea is the most abundant and globally distributed sea turtle species in the world and thus, monitoring this species for persistent organic pollutants, such as perfluorinated chemicals, is fundamental for their protection. This study was the first to evaluate the occurrence of five PFCAs (PFOA, PFNA, PFDA, PFUnA, PFDoA) in liver and blood samples of Olive Ridley turtle population from the Escobilla beach (Oaxaca, Mexico). PFDA and PFUnA were the predominant PFCs in blood samples (detected in 93% and 84% of samples, respectively) and were also present in the highest concentrations. Liver samples showed higher PFCA concentrations than whole blood samples, with PFNA and PFDA the most abundant PFCs congeners in liver samples, detected in 65% and 47% of the samples, respectively. The measured levels of contaminants in the blood samples of Lepidochelys olivacea sea turtles were compared to the levels reported in the literature for other turtle species. While linear significant correlations between PFNA, PFDA and PFUnA concentrations in blood samples and curved carapace lengths were determined, no correlation was found for PFOA, supporting the hypothesis that sea turtles could have a higher ability to eliminate this perfluorinated chemical from their blood than other PFCAs. However, we do not know if the concentrations are species or sampling areas dependent.

  5. A Novel Way To Identify Precursors That Degrade To Perfluorinated Compounds In Activated Sludge Using Ion-Trap Time-Of-Flight Mass Spectrometry

    EPA Science Inventory

    An increasing number of studies have been conducted to investigate the environmental distribution of perfluorinated alkyl compounds (PFCs), many of which are known to be toxic in laboratory animals. Despite growing public concerns, fate and transport of PFCs are little known. M...

  6. Facile and robust dual interaction modification of hexadecyldimethyl amine magnetic nanoparticles for the ultrasensitive analysis of perfluorinated compounds in environmental water.

    PubMed

    Liang, Xiaotong; Zou, Ying; Liu, Shengquan; Chen, Chunyan; Wang, Jianping; Hu, Huiping; Yao, Shouzhuo

    2015-05-01

    In this work, a novel extraction and enrichment technique based on hexadecyldimethyl amine functionalized magnetic nanoparticles has been successfully developed for the preconcentration and ultrasensitive detection of perfluorinated compounds in environmental water samples with high-performance liquid chromatography coupled with tandem triple quadrupole mass spectrometry. As a novel surfactant, hexadecyldimethyl amine functionalized on magnetic nanoparticles was realized through one-step facile and robust quaterization reaction, greatly superior to previous multiple-step and unstable modification. The functional nanoparticles of homogeneous nanospheres and excellent magnetic properties were characterized with scanning electron microscopy, X-ray diffraction patterns, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. Dual mechanisms of both hydrophobic and electrostatic interactions were simultaneously introduced for anionic perfluorinated compounds effective enrichment. Under optimized extraction conditions, satisfactory precision and accuracy for anionic perfluorinated compounds analysis were achieved with good linear ranging from 0.5 to 20 ng/L, as well as fascinating sensitivity with low limits of detection up to 3.0 × 10(-2) -5.0 × 10(-2) ng/L. High preconcentration efficiency and extraction recoveries ranged from 81.04-103.2% with relative standard deviations (n = 5) less than 10% have also been realized. Thereby, our proposed method is convenient and efficient for enrichment, exhibiting good application prospect in future environmental perfluorinated compounds analysis.

  7. 36 CFR 1.3 - Penalties.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Penalties. 1.3 Section 1.3 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR GENERAL PROVISIONS... 1 through 7, 12 and 13 of this chapter, within a park area not covered in paragraphs (b) or (c)...

  8. 45 CFR 1206.1-3 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 4 2011-10-01 2011-10-01 false Definitions. 1206.1-3 Section 1206.1-3 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE GRANTS AND CONTRACTS-SUSPENSION AND TERMINATION AND DENIAL OF APPLICATION FOR REFUNDING Suspension and Termination of Assistance §...

  9. 21 CFR 1.3 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Definitions. 1.3 Section 1.3 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL GENERAL ENFORCEMENT... after shipment or delivery in interstate commerce. (b) Label means any display of written, printed,...

  10. Synthesis of 1,3,3-trinitroazetidine

    DOEpatents

    Hiskey, M.A.; Coburn, M.D.

    1994-08-09

    A process of preparing 1,3,3-trinitroazetidine includes forming a 5-hydroxymethyl-5-nitro-1-alkyltetrahydro-1,3-oxazine, e.g., reacting a 1,3,5-trialkyl hexahydrotriazine and tris(hydroxymethyl)nitromethane, ring opening said 5-hydroxymethyl-5-nitro-1-alkyltetrahydro-1,3-oxazine to form a 3-alkylamino-2-hydroxymethyl-2-nitro-1-propanol salt, ring closing said 3-alkylamino-2-hydroxymethyl-2-nitro-1-propanol salt to form a 3-hydroxymethyl-3-nitro-1-alkylazetidine salt, nitrating said 3-hydroxymethyl-3-nitro-1-alkylazetidine salt to form a 1-alkyl-3,3-dinitroazetidine, and converting said 1-alkyl-3,3-dinitroazetidine into 1,3,3-trinitroazetidine is disclosed. 1 fig.

  11. Synthesis of 1,3,3-trinitroazetidine

    DOEpatents

    Hiskey, Michael A.; Coburn, Michael D.

    1994-01-01

    A process of preparing 1,3,3-trinitroazetidine including forming a 5-hydroxymethyl-5-nitro-1-alkyltetrahydro-1,3-oxazine, e.g., reacting a 1,3,5-trialkyl hexahydrotriazine and tris(hydroxymethyl)nitromethane, ring opening said 5-hydroxymethyl-5-nitro-1-alkyltetrahydro-1,3-oxazine to form a 3-alkylamino-2-hydroxymethyl-2-nitro-1-propanol salt, ring closing said 3-alkylamino-2-hydroxymethyl-2-nitro-1-propanol salt to form a 3-hydroxymethyl-3-nitro-1-alkylazetidine salt, nitrating said 3-hydroxymethyl-3-nitro-1-alkylazetidine salt to form a 1-alkyl-3,3-dinitroazetidine, and converting said 1-alkyl-3,3-dinitroazetidine into 1,3,3-trinitroazetidine is disclosed.

  12. Monitoring perfluorinated surfactants in biota and surface water samples following an accidental release of fire-fighting foam into Etobicoke Creek.

    PubMed

    Moody, Cheryl A; Martin, Jonathan W; Kwan, Wai Chi; Muir, Derek C G; Mabury, Scott A

    2002-02-15

    Perfluorinated surfactants have emerged as priority environmental contaminants due to recent reports of their detection in environmental and biological matrices as well as concerns regarding their persistence and toxicity. In June 2000, 22000 L of fire retardant foam containing perfluorinated surfactants was accidentally released at L. B. Pearson International Airport, Toronto, ON, and subsequently entered into Etobicoke Creek, a tributary to Lake Ontario. A suite of analytical tools that include liquid chromatography/tandem mass spectrometry (LC/MS/MS) and 19F NMR were employed to characterize fish (common shiner, Notropus cornutus) and surface water samples collected following the discharge of the perfluorinated material. Total perfluoroalkanesulfonate (4, 6, and 8 carbons) concentrations in fish liver samples ranged from 2.00 to 72.9 microg/g, and total perfluorocarboxylate (5-14 carbons) concentrations ranged from 0.07 to 1.02 microg/g. In addition to fish samples, total perfluoroalkanesulfonate (6 and 8 carbons) concentrations were detected in creek water samples by LC/MS/MS over a 153 day sampling period with concentrations ranging from <0.017 to 2260 microg/L; perfluorooctanoate concentrations (<0.009-11.3 microg/L) were lower than those observed for the perfluoroalkane-sulfonates. By 19F NMR, the total perfluorinated surfactant concentrations in surface water samples ranged from < 10 to 17000 microg/L. A bioaccumulation factor range of 6300-125000 was calculated for perfluorooctanesulfonate, based on concentrations in fish liver and surface water. The residence time of perfluorooctanesulfonate in Etobicoke Creek as well as the high bioaccumulation in fish liver suggests that perfluorinated surfactants will persist and bioaccumulate following release into the aquatic environment.

  13. Radiation Effects on Fused Biconical Taper Wavelength Division Multiplexers

    NASA Technical Reports Server (NTRS)

    Gutierrez, Roman C.; Swift, Gary M.; Dubovitsky, Serge; Bartman, Randall K.; Barnes, Charles E.; Dorsky, Leonard

    1994-01-01

    The effects of radiation on fused biconical taper wavelength division multiplexers are presented. A theoretical model indicates that index changes in the fiber are primarily responsible for the degradation of these devices.

  14. Astronaut Hoffman replaces fuse plugs on Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Astronaut Jeffrey A. Hoffman sees to the replacement of fuse plugs on the Hubble Space Telescope (HST) during the first of five space walks. Thunderclouds are all that is visible on the dark earth in the background.

  15. Quantification of residual stress from photonic signatures of fused silica

    NASA Astrophysics Data System (ADS)

    Cramer, K. Elliott; Hayward, Maurice; Yost, William T.

    2014-02-01

    A commercially available grey-field polariscope (GFP) instrument for photoelastic examination is used to assess impact damage inflicted upon the outer-most pane of Space Shuttle windows made from fused silica. A method and apparatus for calibration of the stress-optic coefficient using four-point bending is discussed. The results are validated on known material (acrylic) and are found to agree with literature values to within 6%. The calibration procedure is then applied to fused-silica specimens and the stress-optic coefficient is determined to be 2.43 ± 0.54 × 10-12 Pa-1. Fused silica specimens containing impacts artificially made at NASA's Hypervelocity Impact Technology Facility (HIT-F), to simulate damage typical during space flight, are examined. The damage sites are cored from fused silica window carcasses and examined with the GFP. The calibrated GFP measurements of residual stress patterns surrounding the damage sites are presented.

  16. Technical report on galvanic cells with fused-salt electrolytes

    NASA Technical Reports Server (NTRS)

    Cairns, E. J.; Crouthamel, C. E.; Fischer, A. K.; Foster, M. S.; Hesson, J. C.; Johnson, C. E.; Shimotake, H.; Tevebaugh, A. D.

    1969-01-01

    Technical report is presented on sodium and lithium cells using fused salt electrolytes. It includes a discussion of the thermally regenerative galvanic cell and the secondary bimetallic cell for storage of electricity.

  17. Serum concentrations of perfluorinated compounds (PFC) among selected populations of children and Adults in California

    PubMed Central

    Wu, Xiangmei (May); Bennett, Deborah H.; Calafat, Antonia M.; Kato, Kayoko; Strynar, Mark; Andersen, Erik; Moran, Rebecca E.; Tancredi, Daniel J.; Tulve, Nicolle S.; Hertz-Picciotto, Irva

    2016-01-01

    Perfluorinated compounds (PFCs) have been widely used in industrial applications and consumer products. Their persistent nature and potential health impacts are of concern. Given the high cost of collecting serum samples, this study is to understand whether we can quantify PFC serum concentrations using factors extracted from questionnaire responses and indirect measurements, and whether a single serum measurement can be used to classify an individual’s exposure over a one-year period. The study population included three demographic groups: young children (2–8 years old) (N=67), parents of young children (<55 years old) (N=90), and older adults (>55 years old) (N=59). PFC serum concentrations, house dust concentrations, and questionnaires were collected. The geometric mean of perfluorooctane sulfonic acid (PFOS) was highest for the older adults. In contrast, the geometric mean of perfluorooctanoic acid (PFOA) was highest for children. Serum concentrations of the parent and the child from the same family were moderately correlated (Spearman correlation (r)=0.26–0.79, p<0.05), indicating common sources within a family. For adults, age, having occupational exposure or having used fire extinguisher, frequencies of consuming butter/margarine, pork, canned meat entrées, tuna and white fish, freshwater fish, and whether they ate microwave popcorn were significantly positively associated with serum concentrations of individual PFCs. For children, residential dust concentrations, frequency of wearing waterproof clothes, frequency of having canned fish, hotdogs, chicken nuggets, French fries, and chips, and whether they ate microwave popcorn were significant positive predictors of individual PFC serum concentrations. In addition, the serum concentrations collected in a subset of young children (N=20) and the parents (N=42) one year later were strongly correlated (r=0.68–0.98, p<0.001) with the levels measured at the first visits, but showed a decreasing trend

  18. Theoretical study of the decomposition pathways and products of C5- perfluorinated ketone (C5 PFK)

    NASA Astrophysics Data System (ADS)

    Fu, Yuwei; Wang, Xiaohua; Li, Xi; Yang, Aijun; Han, Guohui; Lu, Yanhui; Wu, Yi; Rong, Mingzhe

    2016-08-01

    Due to the high global warming potential (GWP) and increasing environmental concerns, efforts on searching the alternative gases to SF6, which is predominantly used as insulating and interrupting medium in high-voltage equipment, have become a hot topic in recent decades. Overcoming the drawbacks of the existing candidate gases, C5- perfluorinated ketone (C5 PFK) was reported as a promising gas with remarkable insulation capacity and the low GWP of approximately 1. Experimental measurements of the dielectric strength of this novel gas and its mixtures have been carried out, but the chemical decomposition pathways and products of C5 PFK during breakdown are still unknown, which are the essential factors in evaluating the electric strength of this gas in high-voltage equipment. Therefore, this paper is devoted to exploring all the possible decomposition pathways and species of C5 PFK by density functional theory (DFT). The structural optimizations, vibrational frequency calculations and energy calculations of the species involved in a considered pathway were carried out with DFT-(U)B3LYP/6-311G(d,p) method. Detailed potential energy surface was then investigated thoroughly by the same method. Lastly, six decomposition pathways of C5 PFK decomposition involving fission reactions and the reactions with a transition states were obtained. Important intermediate products were also determined. Among all the pathways studied, the favorable decomposition reactions of C5 PFK were found, involving C-C bond ruptures producing Ia and Ib in pathway I, followed by subsequent C-C bond ruptures and internal F atom transfers in the decomposition of Ia and Ib presented in pathways II + III and IV + V, respectively. Possible routes were pointed out in pathway III and lead to the decomposition of IIa, which is the main intermediate product found in pathway II of Ia decomposition. We also investigated the decomposition of Ib, which can undergo unimolecular reactions to give the formation

  19. Perfluorinated compounds in coastal waters of Hong Kong, South China, and Korea.

    PubMed

    So, M K; Taniyasu, S; Yamashita, N; Giesy, J P; Zheng, J; Fang, Z; Im, S H; Lam, Paul K S

    2004-08-01

    Perfluorinated compounds (PFCs), such as perfluorooctanesulfonate (PFOS) and related compounds, have recently been identified in the environment. PFOS, the terminal degradation product of many of the PFCs, has been found globally in many wildlife species, as well as open ocean waters, even in remote regions far from sources. In this study, a solid-phase extraction procedure coupled with high-performance liquid chromatography interfaced to high-resolution mass spectrometry was used to isolate, identify, and quantify small concentrations of PFCs in seawater. These techniques were applied to investigate the local sources of PFCs in several industrialized areas of Asia and provide information on how the PFCs are circulated by coastal currents. Ranges of concentrations of PFOS in coastal seawaters of Hong Kong, the Pearl River Delta, including the South China Sea, and Korea were 0.09-3.1, 0.02-12, and 0.04-730 pg/mL, respectively, while those of perfluorooctanoic acid (PFOA) were 0.73-5.5, 0.24-16, and 0.24-320 pg/mL, respectively. Potential sources of PFCs include major industrialized areas along the Pearl River Delta of southern China and major cities of Korea, which are several of the fastest growing industrial and economic regions in the world. Detectable concentrations of PFOS and PFOA in waters of southern China were similar to those in the coastal marine environment of Japan and certain regions in Korea. Concentrations of PFCs in several locations in Korean waters were 10-100-fold greater than those in the other locations on which we report here. The spatial and seasonal variations in PFC concentrations in surface seawaters in the Pearl River Delta and South China Sea indicate the strong influence of the Pearl River discharge on the magnitude and extent of PFC contamination in southern China. All of the concentrations of PFOS were less than those that would be expected to cause adverse effects to aquatic organisms or their predators except for one location in

  20. Occurrence of perfluorinated compounds in raw water from New Jersey public drinking water systems.

    PubMed

    Post, Gloria B; Louis, Judith B; Lippincott, R Lee; Procopio, Nicholas A

    2013-01-01

    Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were previously detected (≥ 4 ng/L) in 65% and 30%, respectively, of 23 New Jersey (NJ) public drinking water systems (PWS) sampled in 2006. We now report on a 2009 study of the occurrence of PFOA, PFOS, and eight other perfluorinated compounds (PFCs) in raw water samples from 30 intakes (18 groundwater and 12 surface water) from 29 additional NJ PWS. Between 1 and 8 PFCs were detected (≥ 5 ng/L) in 21 (70%) of 30 PWS samples at total PFC concentrations of 5-174 ng/L. Although PFOA was the most commonly detected PFC (57% of samples) and was found at the highest maximum concentration (100 ng/L), some of the higher levels of other PFCs were at sites with little or no PFOA. Perfluorononanoic acid was detected more frequently (30%) and at higher concentrations (up to 96 ng/L) than in raw or finished drinking water elsewhere, and it was found at several sites as the sole or predominant PFC, a pattern not reported in other drinking water studies. PFOS, perfluoropentanoic acid, and perfluorohexanoic acid were each detected in more than 20% of samples, while perfluoroheptanoic acid, perfluorobutane sulfonic acid, and perfluorohexane sulfonic acid were detected less frequently. Perfluorobutanoic acid was found only once (6 ng/L), and perfluorodecanoic acid was not detected. Total PFCs were highest in two reservoirs near an airfield; these were also the only sites with total perfluorosulfonic acids higher than total perfluorocarboxylic acids (PFCAs). PFC levels in raw and finished water from the same source were similar at those sites where both were tested. Five wells of two additional NJ PWS known to be contaminated with PFOA were also each sampled 4-9 times in 2010-13 for nine of the same PFCs. Total PFCs (almost completely PFCAs) at one of these PWS located near an industrial source of PFCs were higher than in any other PWS tested (up to 330 ng/L). These results show that multiple PFCs are

  1. Does wet precipitation represent local and regional atmospheric transportation by perfluorinated alkyl substances?

    PubMed

    Taniyasu, Sachi; Yamashita, Nobuyoshi; Moon, Hyo-Bang; Kwok, Karen Y; Lam, Paul K S; Horii, Yuichi; Petrick, Gert; Kannan, Kurunthachalam

    2013-05-01

    Perfluorinated alkyl substances (PFASs) have been found widely in the environment including remote marine locations. The mode of transport of PFASs to remote marine locations is a subject of considerable scientific interest. Assessment of distribution of PFASs in wet precipitation samples (i.e., rainfall and snow) collected over an area covering continental, coastal, and open ocean will enable an understanding of not only the global transport but also the regional transport of PFASs. Nevertheless, it is imperative to examine the representativeness and suitability of wet precipitation matrixes to allow for drawing conclusions on the transport PFASs. In this study, we collected wet precipitation samples including rainfall, surface snow, and snow core from several locations in Japan to elucidate the suitability of these matrixes for describing local and regional transport of PFASs. Rain water collected at various time intervals within a single rainfall event showed high fluxes of PFASs in the first 1-mm deposition. The scavenging rate of PFASs by wet deposition varied depending on the fluorocarbon chain length of PFAS. The depositional fluxes of PFASs measured for continental (Tsukuba, Japan) and open ocean (Pacific Ocean, 1000km off Japanese coast) locations were similar, on the order of a few nanograms per square meter. The PFAS profiles in "freshly" deposited and "aged" (deposited on the ground for a few days) snow samples taken from the same location varied considerably. The freshly deposited snow represents current atmospheric profiles of PFASs, whereas the aged snow sample reflects sequestration of local sources of PFASs from the atmosphere. Post-depositional modifications in PFAS profiles were evident, suggesting reactions of PFASs on snow/ice surface. Transformation of precursor chemicals such as fluorotelomer alcohols into perfluoroalkylcarboxylates is evident on snow surface. Snow cores have been used to evaluate time trends of PFAS contamination in remote

  2. Global equation of state for a glassy material: Fused silica

    SciTech Connect

    Boettger, J.C.

    1994-09-01

    A new SESAME equation of state (EOS) for fused silica has been generated using the computer program GRIZZLY and will be added to the SESAME library as material number 7387. This new EOS provides better agreement with experimental data than was achieved by all previous SESAME EOSs for fused silica. Material number 7387 also constitutes the most realistic SESAME-type EOS generated for any glassy material thus far.

  3. Fused liposome and acid induced method for liposome fusion

    SciTech Connect

    Huang, L.; Connor, J.

    1988-12-06

    This patent describes a method of fusing liposomes. It comprises: preparing a suspension of liposomes containing at least one lipid which has a tendency to form the inverted hexagonal phase and at least 20 mol percent of palmitoylhomocysteine; and in the absence of externally added divalent cations, proteins or other macromolecules, acidifying the liposome suspension to reduce the pH of the liposomes to below pH 7, such that at least about 20% of the liposomes fuse to one another.

  4. Fusing Manual and Machine Feedback in Biomedical Domain

    DTIC Science & Technology

    2014-11-01

    Fusing manual and machine feedback in biomedical domain 1Jainisha Sankhavara, 1Fenny Thakrar, 2Shamayeeta Sarkar, 1Prasenjit Majumder 1DA-IICT...to obtain efficient biomedical document retrieval. We focused on fusing manual and machine feedback runs. Fusion run performs better and gives... feedback was used (top 5 documents were manually judged). we have applied two types of fusions: CombSUM and Z fusion [1] [2]. After the relevance

  5. Convenient synthesis of bis(benzo)-fused BEDT-TTF and higher homologues: new electron donor molecules for organic charge transfer salts and `molecular rulers`

    SciTech Connect

    Parakka, J.P.; Kini, A.M.; Williams, J.M.

    1996-10-01

    A convenient synthesis of bis(benzo)- and bis(naphtho)-fused bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or ET) derivatives, employing the [4+2] cycloaddition reaction of oligo(1,3-dithiole-2,4, 5-trithione) with appropriate alkenes as a key step, is presented.

  6. 21 CFR 1.3 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... REGULATIONS General Provisions § 1.3 Definitions. (a) Labeling includes all written, printed, or graphic... graphic matter on the immediate container of any article, or any such matter affixed to any...

  7. 21 CFR 1.3 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... REGULATIONS General Provisions § 1.3 Definitions. (a) Labeling includes all written, printed, or graphic... graphic matter on the immediate container of any article, or any such matter affixed to any...

  8. 21 CFR 1.3 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... REGULATIONS § 1.3 Definitions. (a) Labeling includes all written, printed, or graphic matter accompanying an... delivery in interstate commerce. (b) Label means any display of written, printed, or graphic matter on...

  9. Screening of perfluorinated compounds in water, sediment and biota of the Llobregat River basin (NE Spain)

    NASA Astrophysics Data System (ADS)

    Campo, Julian; Perez, Francisca; Pico, Yolanda; Farre, Marinella; Barcelo, Damia; Andreu, Vicente

    2014-05-01

    PFCs present significant thermal and chemical stability being persistent in the environment, where they can bio-accumulate and adversely affect humans and wildlife (Llorca et al., 2012). Human exposure to PFCs is of concern since PFCs tend to be associated with fatty acid binding proteins in the liver or albumin proteins in blood, and have been detected in human serum, urine, saliva, seminal plasma and breast milk (Sundstrom et al., 2011). This study is aimed at the screening of 21 perfluorinated compounds (PFCs) in environmental samples by high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS). The main objective is to identify target compounds at low levels in water, sediments and biota of the Llobregat River (2010), second longest river in Catalonia and one of Barcelona's major drinking water resources. PFCs were extracted from water samples by Solid Phase Extraction (SPE); from sediment by ultrasonication with acidified methanol followed by an off-line SPE procedure (Picó et al., 2012), and from biota (fish) with alkaline digestion, clean-up by TurboFlow™ on line technology coupled to LC-MS/MS (Llorca et al., 2012). The limits of detection (LODs) and limits of quantification (LOQs) of the method were calculated by analysis of spiked river water, sediment, and biota with minimum concentrations of each individual compound at a signal-to-noise ratio of 3 and 10, respectively. The LODs and LOQs of the method in river water ranged between 0.004 and 0.8 ng L-1 and between 0.01 and 2 ng L-1, respectively. In sediment LODs were 0.013-2.667 ng g-1 dry weight (dw) and LOQs were 0.04-8 ng g-1 dw, meanwhile in biota these were 0.006-0.7 pg μL-1 and 0.02-2.26 pg μL-1, respectively. Recoveries ranged between 65% and 102% for all target compounds. The method was applied to study the spatial distribution of these compounds in the Llobregat River basin. For this, a total of 40 samples were analysed (14 water, 14 sediments, 12 fishes). Of the 21 target

  10. Process for manufacturing hollow fused-silica insulator cylinder

    SciTech Connect

    Sampayan, Stephen E.; Krogh, Michael L.; Davis, Steven C.; Decker, Derek E.; Rosenblum, Ben Z.; Sanders, David M.; Elizondo-Decanini, Juan M.

    2001-01-01

    A method for building hollow insulator cylinders that can have each end closed off with a high voltage electrode to contain a vacuum. A series of fused-silica round flat plates are fabricated with a large central hole and equal inside and outside diameters. The thickness of each is related to the electron orbit diameter of electrons that escape the material surface, loop, and return back. Electrons in such electron orbits can support avalanche mechanisms that result in surface flashover. For example, the thickness of each of the fused-silica round flat plates is about 0.5 millimeter. In general, the thinner the better. Metal, such as gold, is deposited onto each top and bottom surface of the fused-silica round flat plates using chemical vapor deposition (CVD). Eutectic metals can also be used with one alloy constituent on the top and the other on the bottom. The CVD, or a separate diffusion step, can be used to defuse the deposited metal deep into each fused-silica round flat plate. The conductive layer may also be applied by ion implantation or gas diffusion into the surface. The resulting structure may then be fused together into an insulator stack. The coated plates are aligned and then stacked, head-to-toe. Such stack is heated and pressed together enough to cause the metal interfaces to fuse, e.g., by welding, brazing or eutectic bonding. Such fusing is preferably complete enough to maintain a vacuum within the inner core of the assembled structure. A hollow cylinder structure results that can be used as a core liner in a dielectric wall accelerator and as a vacuum envelope for a vacuum tube device where the voltage gradients exceed 150 kV/cm.

  11. Simultaneous determination of perfluorinated compounds and their potential precursors in mussel tissue and fish muscle tissue and liver samples by liquid chromatography-electrospray-tandem mass spectrometry.

    PubMed

    Zabaleta, I; Bizkarguenaga, E; Prieto, A; Ortiz-Zarragoitia, M; Fernández, L A; Zuloaga, O

    2015-03-27

    An analytical method for the simultaneous determination in fish liver and muscle tissue and mussel samples of 14 perfluorinated compounds (PFCs), including three perfluoroalkylsulfonates (PFSAs), seven perfluorocarboxylic acids (PFCAs), three perfluorophosphonic acids (PFPAs) and perfluorooctanesulfonamide (PFOSA), and 10 potential precursors, including four polyfluoroalkyl phosphates (PAPs), four fluorotelomer saturated acids (FTCAs) and two fluorotelomer unsaturated acids (FTUCAs), was developed in the present work. Different clean-up strategies by means of solid-phase extraction (SPE) using a mix-mode weak anion exchanger (WAX), reverse phase Envi-Carb or a combination of them was optimized and evaluated for the clean-up of focused ultrasonic solid-liquid (FUSLE) extracts before the analysis by liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS/MS). Mix-mode WAX coupled in-line to Envi-Carb was finally selected since it rendered the cleanest extracts and minimum matrix effect. The FUSLE-SPE-LC-MS/MS methodology was validated in terms of recovery, precision and method detection limits (MDLs). Apparent recovery values in the 65-116%, 59-119% and 67-126% range and MDLs in the 0.1-2.7 ng/g, 0.1-3.8 ng/g and 0.2-3.1ng/g range were obtained for liver, mussel and fish muscle tissue samples, respectively. The method developed was applied to the analysis of grey mullet liver (Chelon labrosus) and mussel (Mytilus galloprovincialis) samples from the Basque Coast (North of Spain) and Yellowfin tuna muscle tissue (Thunnus albacares) samples from the Indian Ocean. To the best of our knowledge this is the first method that describes the simultaneous determination of 14 PFCs and 10 potential precursors in fish liver, fish muscle tissue and mussel samples. Besides, this is the first time that 8:2 monosubstituted polyfluorodecyl phosphate (8:2 monoPAP) and 8:2 disubstituted polyfluorodecyl phosphate (8:2 diPAP) were detected in mussel and tuna samples

  12. Microbial production of 1,3-propanediol.

    PubMed

    Sauer, Michael; Marx, Hans; Mattanovich, Diethard

    2008-01-01

    The introduction of economic production processes for 1,3-propanediol is a success story for the creation of a new market for a (bulk) chemical. The compound and its favorable properties have long been known; also the fermentation of glycerol to 1,3-propanediol had been described more than 120 years ago. Nevertheless, the product remained a specialty chemical until recently, when two new processes were introduced, providing 1,3-propanediol at a competitive price. Remarkably, one of the processes is in the field of white biotechnology and based on microbial fermentation, converting a renewable carbon source into a bulk chemical. This review covers the most important patents that led to the commercialization of bio-based 1,3-propanediol. Furthermore, some of the recent developments towards a sustainable industry are addressed. Similar questions arise for a variety of products if they are to be produced bio-based in large scale. However, special emphasis is given to 1,3-propanediol production.

  13. Spectral and spatial characterization of perfluorinated graded-index polymer optical fibers for the distribution of optical wireless communication cells.

    PubMed

    Hajjar, Hani Al; Montero, David S; Lallana, Pedro C; Vázquez, Carmen; Fracasso, Bruno

    2015-02-10

    In this paper, the characterization of a perfluorinated graded-index polymer optical fiber (PF-GIPOF) for a high-bitrate indoor optical wireless system is reported. PF-GIPOF is used here to interconnect different optical wireless access points that distribute optical free-space high-bitrate wireless communication cells. The PF-GIPOF channel is first studied in terms of transmission attenuation and frequency response and, in a second step, the spatial power profile distribution at the fiber output is analyzed. Both characterizations are performed under varying restricted mode launch conditions, enabling us to assess the transmission channel performance subject to potential connectorization errors within an environment where the end users may intervene by themselves on the home network infrastructure.

  14. Perfluorinated compounds and polybrominated diphenyl ethers in great blue heron eggs from Indiana Dunes National Lakeshore, Indiana

    USGS Publications Warehouse

    Custer, T.W.; Kannan, K.; Tao, L.; Saxena, A.R.; Route, B.

    2009-01-01

    In 2007 archived great blue heron (Ardea herodias) eggs collected from Indiana Dunes National Lakeshore, IN, (Indiana Dunes) in 1993 were analyzed for 11 perfluorinated compounds (PFCs) and 7 polybrominated diphenyl ethers (PBDEs). Concentrations of perfluorooctane sulfonate, the major contributor to total PFC concentrations, were below the toxicity thresholds estimated for bobwhite quail (Colinus virginianus) and mallards (Anas platyrhynchos), but within the toxicity threshold estimated for white leghorn chickens (Gallus domesticus). The ranking of PBDE congener concentrations by percent concentration (PBDE-47 > -99 > -100 > -153 > -154 > -28 > -183) was consistent with the Penta-PBDE formulation. Total PBDE concentrations in great blue heron eggs from Indiana Dunes were elevated and probably reflect local contamination from highly urbanized and industrialized inputs into Lake Michigan. Polybrominated diphenyl ether concentrations were within levels associated with altered reproductive behavior in other avian species and based on trends in other Great Lakes birds are probably higher today.

  15. Optical coatings of variable refractive index and high laser-resistance from physical-vapor-deposited perfluorinated amorphous polymer

    DOEpatents

    Chow, Robert; Loomis, Gary E.; Thomas, Ian M.

    1999-01-01

    Variable index optical single-layers, optical multilayer, and laser-resistant coatings were made from a perfluorinated amorphous polymer material by physical vapor deposition. This was accomplished by physically vapor depositing a polymer material, such as bulk Teflon AF2400, for example, to form thin layers that have a very low refractive index (.about.1.10-1.31) and are highly transparent from the ultra-violet through the near infrared regime, and maintain the low refractive index of the bulk material. The refractive index can be varied by simply varying one process parameter, either the deposition rate or the substrate temperature. The thus forming coatings may be utilized in anti-reflectors and graded anti-reflection coatings, as well as in optical layers for laser-resistant coatings at optical wavelengths of less than about 2000 nm.

  16. Optical coatings of variable refractive index and high laser-resistance from physical-vapor-deposited perfluorinated amorphous polymer

    DOEpatents

    Chow, R.; Loomis, G.E.; Thomas, I.M.

    1999-03-16

    Variable index optical single-layers, optical multilayer, and laser-resistant coatings were made from a perfluorinated amorphous polymer material by physical vapor deposition. This was accomplished by physically vapor depositing a polymer material, such as bulk Teflon AF2400, for example, to form thin layers that have a very low refractive index (ca. 1.10--1.31) and are highly transparent from the ultra-violet through the near infrared regime, and maintain the low refractive index of the bulk material. The refractive index can be varied by simply varying one process parameter, either the deposition rate or the substrate temperature. The thus forming coatings may be utilized in anti-reflectors and graded anti-reflection coatings, as well as in optical layers for laser-resistant coatings at optical wavelengths of less than about 2000 nm. 2 figs.

  17. Fate of a broad spectrum of perfluorinated compounds in soils and biota from Tierra del Fuego and Antarctica.

    PubMed

    Llorca, Marta; Farré, Marinella; Tavano, Máximo Sebastián; Alonso, Bruno; Koremblit, Gabriel; Barceló, Damià

    2012-04-01

    In this study, the presence of 18 perfluorinated compounds was investigated in biota and environmental samples from the Antarctica and Tierra de Fuego, which were collected during a sampling campaign carried out along February and March 2010. 61 samples were analysed including fish, superficial soils, guano, algae, dung and tissues of Papua penguin by liquid chromatography coupled to tandem mass spectrometry. The concentrations of PFCs were ranging from 0.10 to 240 ng/g for most of the samples except for penguin dung, which presented levels between 95 and 603 ng/g for perfluorooctane sulfonate, and guano samples from Ushuaia, with concentration levels of 1190-2480 ng/g of perfluorohexanoic acid. PFCs acids presented, in general, the highest levels of concentration and perfluorooctanesulfonate was the most frequently found compound. The present study provides a significant amount of results, which globally supports the previous studies, related to the transport, deposition, biodegradation and bioaccumulation patterns of PFCs.

  18. 30 CFR 57.12037 - Fuses in high-potential circuits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fuses in high-potential circuits. 57.12037... Electricity Surface and Underground § 57.12037 Fuses in high-potential circuits. Fuse tongs or hotline tools, shall be used when fuses are removed or replaced in high-potential circuits....

  19. Carcinogenicity of 1,3-butadiene.

    PubMed Central

    Melnick, R L; Shackelford, C C; Huff, J

    1993-01-01

    1,3-Butadiene, a high-production volume chemical used largely in the manufacture of synthetic rubber, is a multiple organ carcinogen in rats and mice. In inhalation studies conducted in mice by the National Toxicology Program, high rates of early lethal lymphomas occurring at exposure levels of 625 ppm or higher reduced the development and expression of later developing tumors at other sites. Use of survival-adjusted tumor rates to account for competing risk factors provided a clearer indication of the dose responses for 1,3-butadiene-induced neoplasms. An increase in lung tumors in female mice was observed at exposure concentrations as low as 6.25 ppm, the lowest concentration ever used in a long-term carcinogenicity study of this gas. Human exposures to 1,3-butadiene by workers employed at facilities that produce this chemical and at facilities that produce styrene-butadiene rubber have been measured at levels higher than those that cause cancer in animals. Furthermore, epidemiology studies have consistently revealed associations between occupational exposure to 1,3-butadiene and excess mortality due to lymphatic and hematopoietic cancers. In response to the carcinogenicity findings for 1,3-butadiene in animals and in humans, the Occupational Safety and Health Administration has proposed lowering the occupational exposure standard for this chemical from 1000 ppm to 2 ppm. Future work is needed to understand the mechanisms of tumor induction by 1,3-butadiene; however, the pursuit of this research should not delay the reduction of human exposure to this chemical. PMID:8354171

  20. Electric fuses operation, a review: 1. Pre-arcing period

    NASA Astrophysics Data System (ADS)

    Bussière, W.

    2012-02-01

    Electrical needs are continously growing because of many various factors linked to increasing consumption and a green perception. This development - geographical, increasing production, growth of transport network, interconnection of continental networks, diversity of the transport technologies ... - can not be dissociated from electrical safety considerations whatever the voltage level. For the three main levels of electric network - High Voltage, Middle Voltage and Low Voltage - one has to provide efficient electrical safety techniques or schemas which integrate different electrical safety apparatus. Among well-known apparatus we can cite SF6 breakers, HV and MV switchgears (such as MV cells, MV and LV high current vacuum switchgears), and fuses. Electrical fuses are especially used in the MV and LV domains, sometimes as an additional safety device and sometimes as the main electrical safety component which is linked to the electrical current breaking function of electric fuse. In the paper, we will quickly depict the various kinds of electric fuses. We will especially focuss on the physical mechanisms - whatever the type of work, experimental, theoretical, modelling or empirical - prevailing during the pre-arcing period of the electric fuse operation.

  1. Consistency results for the ROC curves of fused classifiers

    NASA Astrophysics Data System (ADS)

    Bjerkaas, Kristopher S.; Oxley, Mark E.; Bauer, Kenneth W., Jr.

    2004-08-01

    The U.S. Air Force is researching the fusion of multiple sensors and classifiers. Given a finite collection of classifiers to be fused one seeks a new classifier with improved performance. An established performance quantifier is the Receiver Operating Characteristic (ROC) curve. This curve allows one to view the probability of detection versus probability of false alarm in one graph. In reality only finite data is available so only an approximate ROC curve can be constructed. Previous research shows that one does not have to perform an experiment for this new fused classifier to determine its ROC curve. If the ROC curve for each individual classifier has been determined, then formulas for the ROC curve of the fused classifier exist for certain fusion rules. This will be an enormous saving in time and money since the performance of many fused classifiers will be determined without having to perform tests on each one. But, again, these will be approximate ROC curves, since they are based on finite data. We show that if the individual approximate ROC curves are consistent then the approximate ROC curve for the fused classifier is also consistent under certain circumstances. We give the details for these circumstances, as well as some examples related to sensor fusion.

  2. Quantification of Residual Stress from Photonic Signatures of Fused Silica

    NASA Technical Reports Server (NTRS)

    Cramer, K. Elliott; Hayward, Maurice; Yost, William E.

    2013-01-01

    A commercially available grey-field polariscope (GFP) instrument for photoelastic examination is used to assess impact damage inflicted upon the outer-most pane of Space Shuttle windows made from fused silica. A method and apparatus for calibration of the stress-optic coefficient using four-point bending is discussed. The results are validated on known material (acrylic) and are found to agree with literature values to within 6%. The calibration procedure is then applied to fused-silica specimens and the stress-optic coefficient is determined to be 2.43 +/- 0.54 x 10(exp -12)/Pa. Fused silica specimens containing impacts artificially made at NASA's Hypervelocity Impact Technology Facility (HIT-F), to simulate damage typical during space flight, are examined. The damage sites are cored from fused silica window carcasses and examined with the GFP. The calibrated GFP measurements of residual stress patterns surrounding the damage sites are presented. Keywords: Glass, fused silica, photoelasticity, residual stress

  3. Bilateral maxillary fused second and third molars: a rare occurrence

    PubMed Central

    Liang, Rui-Zhen; Wu, Jin-Tao; Wu, You-Nong; Smales, Roger J; Hu, Ming; Yu, Jin-Hua; Zhang, Guang-Dong

    2012-01-01

    This case report describes the diagnosis and endodontic therapy of maxillary fused second and third molars, using cone-beam computed tomography (CBCT). A 31-year-old Chinese male, with no contributory medical or family/social history, presented with throbbing pain in the maxillary right molar area following an unsuccessful attempted tooth extraction. Clinical examination revealed what appeared initially to be a damaged large extra cusp on the buccal aspect of the distobuccal cusp of the second molar. However, CBCT revealed that a third molar was fused to the second molar. Unexpectedly, the maxillary left third molar also was fused to the second molar, and the crown of an unerupted supernumerary fourth molar was possibly also fused to the apical root region of the second molar. Operative procedures should not be attempted without adequate radiographic investigation. CBCT allowed the precise location of the root canals of the right maxillary fused molar teeth to permit successful endodontic therapy, confirmed after 6 months. PMID:23222992

  4. A Dogrib History. Grade 1-3.

    ERIC Educational Resources Information Center

    Fraser, Tara

    A publication on the history and traditional lifestyle of the Dogrib Tribe of Canada's Northwest Territories is intended for use in grades 1-3. Text is printed in large, clear letters and accompanied by many drawings. Some subjects covered are cooking, food, canoes, clothes, homes, and games. Sections are devoted to beavers and caribou and their…

  5. Concertedness of 1,3-Dipolar Cycloadditions.

    ERIC Educational Resources Information Center

    Haque, M. Serajul

    1984-01-01

    There are two conflicting views about the mechanism of 1,3-dipolar cycloadditions to multibonds. To reconcile these viewpoints a concerted, spin-paired, diradical mechanism, based on valence bond theory, is proposed. Each of these three mechanisms is discussed. (JN)

  6. Modulating Paratropicity Strength in Diareno-Fused Antiaromatics.

    PubMed

    Frederickson, Conerd K; Zakharov, Lev N; Haley, Michael M

    2016-12-28

    Understanding and controlling the electronic structure of molecules is crucial when designing and optimizing new organic semiconductor materials. We report the regioselective synthesis of eight π-expanded diarenoindacene analogues based on the indeno[1,2-b]fluorene framework along with the computational investigation of an array of diareno-fused antiaromatic compounds possessing s-indacene, pentalene, or cyclobutadiene cores. Analysis of the experimental and computationally derived optoelectronic properties uncovered a linear correlation between the bond order of the fused arene bond and the paratropicity strength of the antiaromatic unit. The Ered(1) for the pentalene and indacene core molecules correlates well with their calculated NICSπZZ values. The findings of this study can be used to predict the properties of, and thus rationally design, new diareno-fused antiaromatic molecules for use as organic semiconductors.

  7. HVI Ballistic Limit Characterization of Fused Silica Thermal Panes

    NASA Technical Reports Server (NTRS)

    Miller, J. E.; Bohl, W. D.; Christiansen, E. L.; Davis, B. A.; Deighton, K. D.

    2015-01-01

    Fused silica window systems are used heavily on crewed reentry vehicles, and they are currently being used on the next generation of US crewed spacecraft, Orion. These systems improve crew situational awareness and comfort, as well as, insulating the reentry critical components of a spacecraft against the intense thermal environments of atmospheric reentry. Additionally, these materials are highly exposed to space environment hazards like solid particle impacts. This paper discusses impact studies up to 10 km/s on a fused silica window system proposed for the Orion spacecraft. A ballistic limit equation that describes the threshold of perforation of a fuse silica pane over a broad range of impact velocities, obliquities and projectile materials is discussed here.

  8. Enhanced characteristics of fused silica fibers using laser polishing

    NASA Astrophysics Data System (ADS)

    Heptonstall, A.; Barton, M. A.; Bell, A. S.; Bohn, A.; Cagnoli, G.; Cumming, A.; Grant, A.; Gustafson, E.; Hammond, G. D.; Hough, J.; Jones, R.; Kumar, R.; Lee, K.; Martin, I. W.; Robertson, N. A.; Rowan, S.; Strain, K. A.; Tokmakov, K. V.

    2014-05-01

    The search for gravitational wave signals from astrophysical sources has led to the current work to upgrade the two largest of the long-baseline laser interferometers, the LIGO detectors. The first fused silica mirror suspensions for the Advanced LIGO gravitational wave detectors have been installed at the LIGO Hanford and Livingston sites. These quadruple pendulums use synthetic fused silica fibers produced using a CO2 laser pulling machine to reduce thermal noise in the final suspension stage. The suspension thermal noise in Advanced LIGO is predicted to be limited by internal damping in the surface layer of the fibers, damping in the weld regions, and the strength of the fibers. We present here a new method for increasing the fracture strength of fused silica fibers by laser polishing of the stock material from which they are produced. We also show measurements of mechanical loss in laser polished fibers, showing a reduction of 30% in internal damping in the surface layer.

  9. Interdisciplinary Treatment of a Fused Lower Premolar with Supernumerary Tooth

    PubMed Central

    Gadimli, Cengiz; Sari, Zafer

    2011-01-01

    The objective of this report is to describe combined orthodontic and endodontic treatment of a fused mandibular premolar with supernumerary tooth. The patient was a 15 year old girl seeking orthodontic treatment for the correction of maxillary and mandibular crowding. Cephalometric examination revealed skeletally Class I relationship. The panoramic radiograph showed a fused tooth with two separate pulp chambers and two separate root canals connecting in apical third. After the endodontic treatment of the fused teeth, the stripping of the supernumerary tooth was performed to establish a Class I canine relationship and to correct midline deviation. At the end of the treatment, the crowding was resolved and positive overjet and overbite was achieved. PMID:21769280

  10. Micromachined contact fuses for earth penetrator applications. LDRD final report

    SciTech Connect

    Davies, B.R.; Montague, S.; Smith, J.H.; Rimkus, V.C.

    1998-01-01

    MEMS is an enabling technology that may provide low-cost devices capable of sensing motion in a reliable and accurate manner. This paper describes preliminary work in MEMS contact fuse development at Sandia National Laboratories. This work leverages a process for integrating both the micromechanical structures and microelectronics circuitry of a MEMS devices on the same chip. The design and test results of an integrated MEMS high-g accelerometer will be detailed. This design could be readily modified to create a high-g switching device suitable for a contact fuse. A potential design for a low-g acceleration measurement device (suitable for such fusing operations as path length measurement device of both whole path length or safe separation distance) for artillery rounds and earth penetrator devices will also be discussed in this document (where 1 g {approx} 9.81 m/s{sup 2}).

  11. On Fusing Recursive Traversals of K-d Trees

    SciTech Connect

    Rajbhandari, Samyam; Kim, Jinsung; Krishnamoorthy, Sriram; Pouchet, Louis-Noel; Rastello, Fabrice; Harrison, Robert J.; Sadayappan, Ponnuswamy

    2016-03-17

    Loop fusion is a key program transformation for data locality optimization that is implemented in production compilers. But optimizing compilers currently cannot exploit fusion opportunities across a set of recursive tree traversal computations with producer-consumer relationships. In this paper, we develop a compile-time approach to dependence characterization and program transformation to enable fusion across recursively specified traversals over k-ary trees. We present the FuseT source-to-source code transformation framework to automatically generate fused composite recursive operators from an input program containing a sequence of primitive recursive operators. We use our framework to implement fused operators for MADNESS, Multiresolution Adaptive Numerical Environment for Scientific Simulation. We show that locality optimization through fusion can offer more than an order of magnitude performance improvement.

  12. Coated Fused Silica Fibers for Enhanced Sensitivity Torsion Pendulum

    NASA Technical Reports Server (NTRS)

    Numata, Kenji; Horowitz, Jordan; Camp, Jordan

    2007-01-01

    In order to investigate the fundamental thermal noise limit of a torsion pendulum using a fused silica fiber, we systematically measured and modeled the mechanical losses of thin fused silica fibers coated by electrically conductive thin metal films. Our results indicate that it is possible to achieve a thermal noise limit for coated silica lower by a factor between 3 and 9, depending on the silica diameter, compared to the best tungsten fibers available. This will allow a corresponding increase in sensitivity of torsion pendula used for weak force measurements, including the gravitational constant measurement and ground-based force noise testing for the Laser Interferometer Space Antenna (LISA) mission.

  13. Push-pull enamines in the synthesis of fused azaheterocycles

    NASA Astrophysics Data System (ADS)

    Dar'in, D. V.; Lobanov, P. S.

    2015-06-01

    The review summarizes published data on the methods of the synthesis of fused nitrogen-containing heterocycles via push-pull enamines (mainly enaminones). Both intermolecular (cyclocondensations) and intramolecular (cyclizations) transformations of enamines, in which both nucleophilic centres of enamine (carbon and nitrogen) are incorporated into the resulting heterocycle, are considered. The data on the reactivity of enamines cover a broad range of facile methods for the preparation of diverse fused pyridines (quinolines, isoquinolines, pyridopyridines, etc.) and pyrroles (indoles, tetrahydrocarbazoles, pyrrolopyridines, etc.). The bibliography includes 191 references.

  14. 1,3,6,8-Tetraazapyrenes: synthesis, solid-state structures, and properties as redox-active materials.

    PubMed

    Geib, Sonja; Martens, Susanne C; Zschieschang, Ute; Lombeck, Florian; Wadepohl, Hubert; Klauk, Hagen; Gade, Lutz H

    2012-07-20

    A series of new tetraazapyrene (TAPy) derivatives has been synthesized by reducing 1,4,5,8-tetranitronaphthalene to its corresponding tin salt (I) and reacting it with perfluorinated alkyl or aryl anhydrides. The resulting 2,7-disubstituted TAPy molecules and the known parent compound 1,3,6,8-tetraazapyrene (II) have been further derivatized by core chlorination and bromination. The brominated compounds served as starting materials for Suzuki cross-coupling reactions with electron-poor arylboronic acids. Single-crystal X-ray analyses established polymorphism for some TAPy compounds. The ground-state geometries of all new TAPy derivatives were modeled with DFT methods [B3PW91/6-31 g(d,p) and B3PW91/6-311+g(d,p)], especially focusing on the energies of the lowest unoccupied molecular orbital (LUMO) and the electron affinities (EA) of the molecules. The results of the calculations were confirmed experimentally by cyclic voltammetry to evaluate the substitution effects at the 2 and 7 position and the core positions, respectively, and gave LUMO energy levels that range from -3.57 to -4.14 eV. Fabrication of organic field-effect transistors (OFETs) with several of these tetraazapyrenes established their potential as organic n-type semiconductors.

  15. Bioaccumulation of perfluorinated carboxylates and sulfonates and polychlorinated biphenyls in laboratory-cultured Hexagenia spp., Lumbriculus variegatus and Pimephales promelas from field-collected sediments.

    PubMed

    Prosser, R S; Mahon, K; Sibley, P K; Poirier, D; Watson-Leung, T

    2016-02-01

    Polychlorinated biphenyls (PCBs) and perfluorinated carboxylates and sulfonates (PFASs) are persistent pollutants in sediment that can potentially bioaccumulate in aquatic organisms. The current study investigates variation in the accumulation of PCBs and PFASs in laboratory-cultured Hexagenia spp., Lumbriculus variegatus and Pimephales promelas from contaminated field-collected sediment using 28-day tests. BSAF(lipid) (lipid-normalized biota-sediment accumulation factor) values for total concentration of PCBs were greater in Hexagenia spp. relative to L. variegatus and P. promelas. The distribution of congeners contributing to the total concentration of PCBs in tissue varied among the three species. Trichlorobiphenyl congeners composed the greatest proportion of the total concentration of PCBs in L. variegatus while tetra- and pentabiphenyl congeners dominated in Hexagenia spp. and P. promelas. Perfluorooctane sulfonate (PFOS) was present in all three species at concentrations greater than all other PFASs analyzed. Hexagenia spp. also produced the greatest BSAF(lipid) and BSAF(ww) (non-lipid-normalized biota-sediment accumulation factor) values for PFOS relative to the other two species. However, this was not the case for all PFASs. The trend of BSAF values and number of carbon atoms in the perfluoroalkyl chain of perfluorinated carboxylates varied among the three species but was similar for perfluorinated sulfonates. Differences in the dominant pathways of exposure (e.g., water, sediment ingestion) likely explain a large proportion of the variation in accumulation observed across the three species.

  16. Fluorocarbon-bonded magnetic mesoporous microspheres for the analysis of perfluorinated compounds in human serum by high-performance liquid chromatography coupled to tandem mass spectrometry.

    PubMed

    Liu, Xiaodan; Yu, Yingjia; Li, Yan; Zhang, Haiying; Ling, Jin; Sun, Xueni; Feng, Jianan; Duan, Gengli

    2014-09-24

    We report herein an extraction method for the analysis of perfluorinated compounds in human serum based on magnetic core-mesoporous shell microspheres with decyl-perfluorinated interior pore-walls (Fe3O4@mSiO2-F17). Thanks to the unique properties of the Fe3O4@mSiO2-F17 microspheres, macromolecules like proteins could be easily excluded from the mesoporous channels due to size exclusion effect, and perfluorinated compounds (PFCs) in protein-rich biosamples such as serum could thus be directly extracted with the fluorocarbon modified on the channel wall without any other pretreatment procedure. The PFCs adsorbed Fe3O4@mSiO2-F17 microspheres could then be simply and rapidly isolated by using a magnet, followed by being identified and quantified by LC-MS/MS (high-performance liquid chromatography coupled to tandem mass spectrometry). Five perfluorinatedcarboxylic acids (C6, C8-C11) and perfluorooctane sulfonate (PFOS) were selected as model analytes. In order to achieve the best extraction efficiency, some important factors including the amount of Fe3O4@mSiO2-F17 microspheres added, adsorption time, type of elution solvent, eluting solvent volume and elution time were investigated. The ranges of the LOD were 0.02-0.05 ng mL(-1) for the six PFCs. The recovery of the optimized method varies from 83.13% to 92.42% for human serum samples.

  17. Gypsum-bonded alumina dental investment for high-fusing casting.

    PubMed

    Yan, M; Takahashi, H

    1998-09-01

    In this study, we developed a new gypsum-bonded investment for high-fusing alloys. The investment was composed of gypsum as a binder and alumina as a refractory. Effects of type of alumina powder and gypsum content on characteristics of the gypsum-bonded alumina investment were investigated. Obtained characteristics of this experimental investment were as follows: fluidities ranged from 48.8 to 88.9 mm; setting times ranged from 21.2 to more than 120 minutes; setting expansions ranged from 0.4 to 1.3%; green strengths showed 0.5 to 4.5 MPa; fired strengths ranged from 0.2 to 1.7 MPa; thermal expansions after firing were -1.60 to 2.16%. Thermal expansion occurred because of the chemical reaction between Al2O3 and CaO decomposed from gypsum. These results suggest that this gypsum-bonded alumina investment with 20 or 25 mass% gypsum content possessed the fundamental properties for high-fusing alloy casting.

  18. Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)

    Integrated Risk Information System (IRIS)

    Hexahydro - 1,3,5 - trinitro - 1,3,5 - triazine ( RDX ) ; CASRN 121 - 82 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health

  19. Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)

    Integrated Risk Information System (IRIS)

    Octahydro - 1,3,5,7 - tetranitro - 1,3,5,7 - tetr . . . ( HMX ) ; CASRN 2691 - 41 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I

  20. 29 CFR 1926.907 - Use of safety fuse.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Use of safety fuse. 1926.907 Section 1926.907 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Blasting and the Use of Explosives § 1926.907...

  1. 59. VIEW OF FUSES AND A CURRENT TRANSFORMER LOCATED IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    59. VIEW OF FUSES AND A CURRENT TRANSFORMER LOCATED IN THE SIGNAL POWER CONDITIONING ROOM. THE CURRENT TRANSFORMER (UPPER RIGHT) IS AN INDUCTION COUPLED SENSOR WHICH IS USED TO REDUCE HIGH CURRENT TO ANALOGOUS LOW VALUES SAFE TO USE IN CONTROL ROOM CIRCUITRY. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

  2. Fused-Ring Oxazolopyrrolopyridopyrimidine Systems with Gram-Negative Activity

    PubMed Central

    Chen, Yiyuan; Moloney, Jonathan G.; Christensen, Kirsten E.; Moloney, Mark G.

    2017-01-01

    Fused polyheterocyclic derivatives are available by annulation of a tetramate scaffold, and been shown to have antibacterial activity against a Gram-negative, but not a Gram-positive, bacterial strain. While the activity is not potent, these systems are structurally novel showing, in particular, a high level of polarity, and offer potential for the optimization of antibacterial activity. PMID:28098784

  3. The burning fuse model of unbecoming in time

    NASA Astrophysics Data System (ADS)

    Norton, John D.

    2015-11-01

    In the burning fuse model of unbecoming in time, the future is real and the past is unreal. It is used to motivate the idea that there is something unbecoming in the present literature on the metaphysics of time: its focus is merely the assigning of a label "real."

  4. Crossed fused renal ectopia: Challenges in diagnosis and management

    PubMed Central

    Solanki, Shailesh; Bhatnagar, Veereshwar; Gupta, Arun K.; Kumar, Rakesh

    2013-01-01

    Aim: Crossed fused renal ectopia is a rare congenital malformation, which is reported to be usually asymptomatic but may have varied presentations. This survey was conducted to study the clinical profile and the challenges posed in the management of this entity. Materials and Methods: Retrospective analysis of 6 patients diagnosed to have crossed fused renal ectopia during 1997-2010. The diagnosis was confirmed during surgical exploration in one patient. In one patient it was detected on antenatal ultrasonography and in the other 4 patients it was detected during investigations for abdominal pain, abdominal mass, anorectal malformation and urinary tract infection. Results: The left moiety was crossed and fused with the right moiety in 4 cases. Ultrasonography was found to be a good screening investigation with useful diagnostic contributions from CT scans, radionuclide scintigraphy and magnetic resonance urography. Micturating cystourethrography revealed presence of VUR in 4 cases, 3 of whom have undergone ureteric reimplantation. Two patients required pyeloplasty for pelviureteric junction obstruction; in one of these patients the upper ureter was entrapped in the isthmus. In one patient, a non-functioning moiety resulted in nephrectomy. All children were asymptomatic at last follow-up with stable renal functions. Conclusions: Crossed fused renal ectopia was detected in most patients during investigation for other problems. It was found more commonly in boys. The left moiety was crossed to the right in the majority of cases. Associated urological problems were found in most cases and required the appropriate surgical management. PMID:23599575

  5. 40. Main fuses and knife switch for power to the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    40. Main fuses and knife switch for power to the bridge, located in the control house. This is one of two located at either end of the main electrical panel (photograph 41). Facing east. - Henry Ford Bridge, Spanning Cerritos Channel, Los Angeles-Long Beach Harbor, Los Angeles, Los Angeles County, CA

  6. Quantification of residual stress from photonic signatures of fused silica

    SciTech Connect

    Cramer, K. Elliott; Yost, William T.; Hayward, Maurice

    2014-02-18

    A commercially available grey-field polariscope (GFP) instrument for photoelastic examination is used to assess impact damage inflicted upon the outer-most pane of Space Shuttle windows made from fused silica. A method and apparatus for calibration of the stress-optic coefficient using four-point bending is discussed. The results are validated on known material (acrylic) and are found to agree with literature values to within 6%. The calibration procedure is then applied to fused-silica specimens and the stress-optic coefficient is determined to be 2.43 ± 0.54 × 10{sup −12} Pa{sup −1}. Fused silica specimens containing impacts artificially made at NASA’s Hypervelocity Impact Technology Facility (HIT-F), to simulate damage typical during space flight, are examined. The damage sites are cored from fused silica window carcasses and examined with the GFP. The calibrated GFP measurements of residual stress patterns surrounding the damage sites are presented.

  7. Improved synthesis of 3-aryl isoxazoles containing fused aromatic rings

    PubMed Central

    Mirzaei, Yousef R.; Weaver, Matthew J.; Steiger, Scott A.; Kearns, Alison K.; Gajewski, Mariusz P.; Rider, Kevin C.; Beall, Howard D.; Natale, N.R.

    2012-01-01

    A critical comparison of methods to prepare sterically hindered 3-aryl isoxazoles containing fused aromatic rings using the nitrile oxide cycloaddition (NOC) reveal that modification of the method of Bode, Hachisu, Matsuura, and Suzuki (BHMS), utilizing either triethylamine as base or sodium enolates of the diketone, ketoester, and ketoamide dipolarophiles, respectively, was the method of choice for this transformation. PMID:23526841

  8. Non-invasive management of fused upper incisors.

    PubMed

    Samimi, Pouran; Shirban, Mohammad-Reza; Arbabzadeh-Zavareh, Farahnaz

    2012-01-01

    The union of two different dental sprouts which can happen in any phase of dental development is commonly called fusion. This developmental anomaly may cause clinical problems including esthetic impairment, which are mainly treated by endodontic and surgical treatments. There are a few reports of conservative not invasive treatment of fused incisors teeth through restorative or prosthetic techniques. They are rarely reported in mandibular posterior teeth. This paper presents an unusual case of fusion of 7 and 8, and also 9 and 10 teeth which was treated with a nonendodontic and nonsurgical conservative approach. Patient was a healthy18-year-old female with chief complaint of bad-looking teeth that in intraoral examination revealed the fusion of 7 and 8, and also 9 and 10 teeth. The space between the mesial of the 6 and 11 teeth was reconstructed. Diastema between the fused teeth was closed. A new lateral tooth was replaced between the fused teeth (7 and 8) and 6 tooth with direct fiber-reinforced composite. The space between the fused teeth (9 and 10) and also tooth 11 was partially closed. Gingival papillas were reconstructed using pink composite. The mandibular anterior missing teeth were replaced with rochett bridge. At the end of treatment the esthetic of the patient was improved. As the treatment was not invasive, major complications are not expected; however, there is potential for eventual long-term periodontal problems due to poor oral hygiene. Debonding of the rochett bridge may happen as well.

  9. Non-invasive management of fused upper incisors

    PubMed Central

    Samimi, Pouran; Shirban, Mohammad-Reza; Arbabzadeh-Zavareh, Farahnaz

    2012-01-01

    The union of two different dental sprouts which can happen in any phase of dental development is commonly called fusion. This developmental anomaly may cause clinical problems including esthetic impairment, which are mainly treated by endodontic and surgical treatments. There are a few reports of conservative not invasive treatment of fused incisors teeth through restorative or prosthetic techniques. They are rarely reported in mandibular posterior teeth. This paper presents an unusual case of fusion of 7 and 8, and also 9 and 10 teeth which was treated with a nonendodontic and nonsurgical conservative approach. Patient was a healthy18-year-old female with chief complaint of bad-looking teeth that in intraoral examination revealed the fusion of 7 and 8, and also 9 and 10 teeth. The space between the mesial of the 6 and 11 teeth was reconstructed. Diastema between the fused teeth was closed. A new lateral tooth was replaced between the fused teeth (7 and 8) and 6 tooth with direct fiber-reinforced composite. The space between the fused teeth (9 and 10) and also tooth 11 was partially closed. Gingival papillas were reconstructed using pink composite. The mandibular anterior missing teeth were replaced with rochett bridge. At the end of treatment the esthetic of the patient was improved. As the treatment was not invasive, major complications are not expected; however, there is potential for eventual long-term periodontal problems due to poor oral hygiene. Debonding of the rochett bridge may happen as well. PMID:22363372

  10. 30 CFR 56.12036 - Fuse removal or replacement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Fuse removal or replacement. 56.12036 Section 56.12036 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES...

  11. 30 CFR 56.12036 - Fuse removal or replacement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Fuse removal or replacement. 56.12036 Section 56.12036 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES...

  12. 30 CFR 56.12036 - Fuse removal or replacement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fuse removal or replacement. 56.12036 Section 56.12036 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES...

  13. 30 CFR 56.12036 - Fuse removal or replacement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Fuse removal or replacement. 56.12036 Section 56.12036 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES...

  14. 30 CFR 56.12036 - Fuse removal or replacement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Fuse removal or replacement. 56.12036 Section 56.12036 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES...

  15. 30 CFR 18.52 - Renewal of fuses.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Renewal of fuses. 18.52 Section 18.52 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and Design...

  16. METHOD OF SEPARATING FISSION PRODUCTS FROM FUSED BISMUTH-CONTAINING URANIUM

    DOEpatents

    Wiswall, R.H.

    1958-06-24

    A process is described for removing metal selectively from liquid metal compositions. The method effects separation of flssion product metals selectively from dilute solution in fused bismuth, which contains uraniunn in solution without removal of more than 1% of the uranium. The process comprises contacting the fused bismuth with a fused salt composition consisting of sodium, potassium and lithium chlorides, adding to fused bismuth and molten salt a quantity of bismuth chloride which is stoichiometrically required to convert the flssion product metals to be removed to their chlorides which are more stable in the fused salt than in the molten metal and are, therefore, preferentially taken up in the fused salt phase.

  17. Biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine

    SciTech Connect

    McCormick, N.G.; Cornell, J.H.; Kaplan, A.M.

    1981-11-01

    Biodegradation of the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) occurs under anaerobic conditions, yielding a number of products, including: hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine, hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine, hexahydro-1,3,5-trinitroso-1,3,5-triazine, hydrazine, 1,1-dimethylhydrazine, 1,2-dimethylhydrazine, formaldehyde, and methanol. A scheme for the biodegradation of RDX is poposed which proceeds via successive reduction of the nitro groups to a point where destabilization and fragmentation of the ring occurs. The noncyclic degradation products arise via subsequent reduction and rearrangement reactions of the fragments. The scheme suggests the presence of several additional compounds, not yet identified. Several of the products are mutagenic or carcinogenic or both. Anaerobic treatment of RDX wastewaters, which also contain high nitrate levels, would permit the denitrification to occur, with concurrent degradation of RDX ultimately to a mixture of hydrazines and methanol. The feasibility of using an aerobic mode in the further degradation of these products is discussed.

  18. Biodegradation of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine

    PubMed Central

    McCormick, N. G.; Cornell, J. H.; Kaplan, A. M.

    1981-01-01

    Biodegradation of the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) occurs under anaerobic conditions, yielding a number of products, including: hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine, hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine, hexahydro-1,3,5-trinitroso-1,3,5-triazine, hydrazine, 1,1-dimethyl-hydrazine, 1,2-dimethylhydrazine, formaldehyde, and methanol. A scheme for the biodegradation of RDX is proposed which proceeds via successive reduction of the nitro groups to a point where destabilization and fragmentation of the ring occurs. The noncyclic degradation products arise via subsequent reduction and rearrangement reactions of the fragments. The scheme suggests the presence of several additional compounds, not yet identified. Several of the products are mutagenic or carcinogenic or both. Anaerobic treatment of RDX wastewaters, which also contain high nitrate levels, would permit the denitrification to occur, with concurrent degradation of RDX ultimately to a mixture of hydrazines and methanol. The feasibility of using an aerobic mode in the further degradation of these products is discussed. PMID:16345884

  19. The Association of Prenatal Exposure to Perfluorinated Chemicals with Glucocorticoid and Androgenic Hormones in Cord Blood Samples: The Hokkaido Study

    PubMed Central

    Goudarzi, Houman; Araki, Atsuko; Itoh, Sachiko; Sasaki, Seiko; Miyashita, Chihiro; Mitsui, Takahiko; Nakazawa, Hiroyuki; Nonomura, Katsuya; Kishi, Reiko

    2016-01-01

    Background: Perfluorinated chemicals (PFCs) disrupt cholesterol homeostasis. All steroid hormones are derived from cholesterol, and steroid hormones such as glucocorticoids and androgenic hormones mediate several vital physiologic functions. However, the in utero effects of PFCs exposure on the homeostasis of these steroid hormones are not well understood in humans. Objectives: We examined the relationship between prenatal exposure to perfluorooctane sulfonate (PFOS)/perfluorooctanoate (PFOA) and cord blood levels of glucocorticoid and androgenic hormones. Methods: We conducted a hospital-based birth cohort study between July 2002 and October 2005 in Sapporo, Japan (n = 514). In total, 185 mother–infant pairs were included in the present study. Prenatal PFOS and PFOA levels in maternal serum samples were measured using liquid chromatography–tandem mass spectrometry (LC-MS-MS). Cord blood levels of glucocorticoid (cortisol and cortisone) and androgenic hormones [dehydroepiandrosterone (DHEA) and androstenedione] were also measured in the same way. Results: We found a dose–response relationship of prenatal PFOS, but not PFOA, exposure with glucocorticoid levels after adjusting for potential confounders. Cortisol and cortisone concentrations were –23.98-ng/mL (95% CI: –0.47.12, –11.99; p for trend = 0.006) and –63.21-ng/mL (95% CI: –132.56, –26.72; p for trend < 0.001) lower, respectively, in infants with prenatal PFOS exposure in the fourth quartile compared with those in the first quartile. The highest quartile of prenatal PFOS exposure was positively associated with a 1.33-ng/mL higher DHEA level compared with the lowest quartile (95% CI: 0.17, 1.82; p for trend = 0.017), whereas PFOA showed a negative association with DHEA levels (quartile 4 vs. quartile 1: –1.23 ng/mL, 95% CI: –1.72, –0.25; p for trend = 0.004). We observed no significant association between PFCs and androstenedione levels. Conclusions: Our results indicate that prenatal

  20. Focused ultrasound solid-liquid extraction for the determination of perfluorinated compounds in fish, vegetables and amended soil.

    PubMed

    Zabaleta, Itsaso; Bizkarguenaga, Ekhiñe; Iparragirre, Arantza; Navarro, Patricia; Prieto, Ailette; Fernández, Luis Ángel; Zuloaga, Olatz

    2014-02-28

    In the present work a method was developed for the determination of different perfluorinated compounds (PFCs), including three perfluorinated sulfonic acids (PFSAs), seven perfluorocarboxylic acids (PFCAs), three perfluorophosphonic acids (PFPAs) and perfluorooctanesulfonamide (PFOSA) in fish, vegetables and amended soil samples based on focused ultrasound solid-liquid extraction (FUSLE) followed by solid-phase extraction (SPE) clean-up and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Different variables affecting the chromatographic separation (column type and pH of the mobile phase), the electrospray ionization (capillary voltage, nebulizer pressure and drying gas flow) and mass spectrometric detection (fragmentor voltage and collision energy) were optimized in order to improve the sensitivity of the separation and detection steps. In the case of FUSLE variables such as the solvent type, the solvent volume, the extraction temperature, the sonication and extraction time and the percentage of applied irradiation power were studied. Under optimized conditions, sonication of 2.5min with pulse times on of 0.8s and pulse times off of 0.2s in 7mL of (9:1) acetonitrile (ACN): water mixture in duplicate guaranteed exhaustive extraction of the matrices analyzed. Due to the non-selective extraction using FUSLE, different SPE cartridges (200-mg Waters Oasis-HLB, 150-mg Waters Oasis-WAX and 150-mg Waters Oasis-MAX) were tested in terms of extraction efficiency and matrix effect both in the extraction and detection steps. Mix mode SPE using Waters Oasis-WAX provided the best extraction efficiencies with the lowest matrix effect. The final method was validated in terms of recovery at two fortification levels (in the 80-120% for most of the analytes and matrices), precision (relative standard deviation in the 2-15% range) and method detection limits (MDLs, 0.3-12.4ng/g for vegetables, 0.2-12.5ng/g for fish and 1-22ng/g for amended soil). Finally the method was

  1. Temporal trends of polychlorinated biphenyls, polybrominated diphenyl ethers, and perfluorinated compounds in Chinese sturgeon (Acipenser sinensis) eggs (1984-2008).

    PubMed

    Jianxian, Sun; Hui, Peng; Jianying, Hu

    2015-02-03

    Because investigation on the temporal trends of persistent halogenated compounds (PHCs) is necessary to predict their future impacts on the environment and human health and evaluate the effectiveness of regulations on their production and usage, it is of concern to investigate annual temporal trends of PHCs in biota samples. This study examined the temporal trends of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and perfluorinated compounds (PFCs) in Chinese sturgeon (Acipenser sinensis) eggs over a period of 25 years (1984-2008), and 62 PCBs (19.2-1030 ng/g dw for total PCBs), 16 PBDEs (4.7-572 ng/g dw for total PBDEs), and 14 PFCs (26-46 ng/g dw for total PFCs) were detected. Although a decreasing temporal trend was observed for total PCBs with annual reduction rate of 3.4% (ρ = 0.005), a clear break point was observed around 1991, indicating their continuing emission in the 1980s in China. All major PBDEs showed increasing temporal trends, with annual change rates at 3.5-10.2% over the 25 years, but a sharp decreasing trend was observed after 2006, indicating a rapid response to the banning of PBDE usage in China in 2004. The greatest annual rate of increase was observed for BDE-28 (10.2%) followed by BDE-100 (7.7%), which would be due to metabolism input from higher brominated PBDEs. Significantly increasing temporal trends were observed for all PFCs, and the annual rates of increase were 7.9% and 5.9% for total perfluorinated carboxylic acids and perfluorooctanesulfonate (PFOS), respectively. A peak concentration for PFOS was observed in 1989, which may be related to the import history of PFCs in China. The present study is the first report of systematic temporal trends of PHCs in biota samples from China and shows that regulatory policy is needed to reduce their potential health and ecological risk in China considering the increasing temporal trends of PBDEs and PFCs.

  2. Intramolecular Diels–Alder/1,3-Dipolar Cycloaddition Cascade of 1,3,4-Oxadiazoles

    PubMed Central

    Elliott, Gregory I.; Fuchs, James R.; Blagg, Brian S. J.; Ishikawa, Hayato; Tao, Houchao; Yuan, Z.-Q.; Boger, Dale L.

    2008-01-01

    Full details of a systematic exploration of the intramolecular [4+2]/[3+2] cycloaddition cascade of 1,3,4-oxadiazoles are disclosed in which the scope and utility of the reaction are defined. PMID:16895427

  3. CMMI(Registered) for Acquisition, Version 1.3. CMMI-ACQ, V1.3

    DTIC Science & Technology

    2010-11-01

    So Norimatsu, Norimatsu Process Engineering Lab, Inc. Mary Lynn Penn, Lockheed Martin Corporation David (Mike) Phillips , Software Engineering...CMMI ® for Acquisition, Version 1.3 CMMI-ACQ, V1.3 CMMI Product Team Improving processes for acquiring better products and services...November 2010 TECHNICAL REPORT CMU/SEI-2010-TR-032 ESC-TR-2010-032 Software Engineering Process Management Program Unlimited distribution

  4. Silyl- and disilanyl-1,3-butadiyne polymers from hexachloro-1,3-butadiene

    DOEpatents

    Barton, T.J.; Ijadi-Maghsoodi, S.

    1990-10-23

    Organosilane polymers having recurring silylene-1,3-butadiyne and/or disilylene-1,3-butadiyne units are prepared in a one-pot synthesis from hexachlorobutadiene. Depending on the organic substituents (R and R[prime]), these polymers have useful film-forming properties, and are converted to the ceramic, silicon carbide upon heating a very uniform high char yields. They can also be pulled into fibers. The polymers are thermally crosslinked above 100 C.

  5. Silyl- and disilanyl-1,3-butadiyne polymers from hexachloro-1,3-butadiene

    DOEpatents

    Barton, Thomas J.; Ijadi-Maghsoodi, Sina

    1990-10-23

    Organosilane polymers having recurring silylene-1,3-butadiyne and/or disilylene-1,3-butadiyne units are prepared in a one-pot synthesis from hexachlorobutadiene. Depending on the organic substituents (R and R'), these polymers have useful film-forming properties, and are converted to the ceramic, silicon carbide upon heating a very uniform high char yields. They can also be pulled into fibers. The polymers are thermally crosslinked above 100.degree. C.

  6. Perfluorinated alkyl substances in serum of the southern Chinese general population and potential impact on thyroid hormones.

    PubMed

    Li, Yangjie; Cheng, Yating; Xie, Zhiyong; Zeng, Feng

    2017-02-27

    In this study, eight perfluorinated alkyl substances (PFASs) and five thyroid hormones (TSH, FT4, FT3, TGAb, and TMAb) were determined in 202 human serum samples of the general population of Guangdong, Guangxi and Hainan provinces in southern China. Σ8PFASs concentrations ranged from 0.85 to 24.3 ng/mL with a mean value of 4.66 ng/mL. The PFASs composition profiles of human serum samples nearly make no difference at different locations. A significant increase was observed for ∑8PFASs, PFOS, and PFHxS concentrations with age (p < 0.01). Gender-related differences were found; PFOS, PFHxS, PFBS, and PFOA levels were higher in males (p < 0.05), and the mean concentration of ∑8PFASs was 1.5 times greater in males (6.02 ng/mL) than in females (4.15 ng/mL). PFOS and ∑8PFASs were significantly negatively correlated with FT3 and FT4 and positively correlated with TSH while PFPeA and PFHxA were significantly positively correlated with TGAb and TMAb in all the samples. The opposite associations between FT3, TSH and PFOS, PFOA and PFHxS levels in hypothyroidism and hyperthyroidism group indicate that the PFOS, PFOA and PFHxS enhance the negative feedback mechanisms of the thyroid gland.

  7. Perfluorinated alkyl substances in serum of the southern Chinese general population and potential impact on thyroid hormones

    PubMed Central

    Li, Yangjie; Cheng, Yating; Xie, Zhiyong; Zeng, Feng

    2017-01-01

    In this study, eight perfluorinated alkyl substances (PFASs) and five thyroid hormones (TSH, FT4, FT3, TGAb, and TMAb) were determined in 202 human serum samples of the general population of Guangdong, Guangxi and Hainan provinces in southern China. Σ8PFASs concentrations ranged from 0.85 to 24.3 ng/mL with a mean value of 4.66 ng/mL. The PFASs composition profiles of human serum samples nearly make no difference at different locations. A significant increase was observed for ∑8PFASs, PFOS, and PFHxS concentrations with age (p < 0.01). Gender-related differences were found; PFOS, PFHxS, PFBS, and PFOA levels were higher in males (p < 0.05), and the mean concentration of ∑8PFASs was 1.5 times greater in males (6.02 ng/mL) than in females (4.15 ng/mL). PFOS and ∑8PFASs were significantly negatively correlated with FT3 and FT4 and positively correlated with TSH while PFPeA and PFHxA were significantly positively correlated with TGAb and TMAb in all the samples. The opposite associations between FT3, TSH and PFOS, PFOA and PFHxS levels in hypothyroidism and hyperthyroidism group indicate that the PFOS, PFOA and PFHxS enhance the negative feedback mechanisms of the thyroid gland. PMID:28240244

  8. An Assessment of Perfluorinated Organic Compounds and the Potentail Impacts to Water Quality and Biota in Coastal Ecosystems

    NASA Astrophysics Data System (ADS)

    Erhunse, A.; Gragg, R.

    2006-12-01

    Urbanized estuaries are well-documented to have elevated contaminant levels in sediments, water and associated biota. Most previous research efforts examining the effects of anthropogenic contamination in urbanized estuaries has focused on persistent priority pollutants, such as trace metals, pesticides, PCBs and PAHs. Recently, concerns have been raised about the occurrence, transport and distribution and effects of emerging contaminants being released into coastal watersheds through upland runoff from both urban and agricultural lands, sewage discharges, industrial releases, and aquaculture. Apalachicola Bay a major estuarine, commercial and recreational seafood resource is the endpoint of the Apalachicola-Chattahoochee-Flint River Basin. Today the river basin encapsulates a vast and evolving expanse of agricultural, urban, industrial, silvaculture, and natural landscapes and activities. The purpose of this study is to monitor the occurrence of an emerging class of compounds (perfluorinated organic compounds) in the Apalachicola Bay watershed. Given the dynamic growth and development up river from the Bay organic substances (lipophillic and water soluble compounds) inputs may be increasing and impacting the ecology of the Bay which compared to other bay areas is at this time relatively pristine. This issue can be investigated utilizing in-situ permeable membrane sampling devices specific for lipophillic and water-soluble compounds in concert with sediment samples. The results may serve as a baseline for the hypothesized increase in inputs coinciding with upstream and coastal development.

  9. Extraction of perfluorinated alkyl acids from human serum for determination of the combined xenoestrogenic transactivity: a method development.

    PubMed

    Bjerregaard-Olesen, Christian; Bossi, Rossana; Bech, Bodil Hammer; Bonefeld-Jørgensen, Eva Cecilie

    2015-06-01

    Humans are exposed to perfluorinated alkyl acids (PFAAs) through food, drinking water, consumer products, dust, etc. The human metabolism and excretion of the long-chain PFAAs is slow with half-lives up to 8.8years. Studies suggest that the PFAAs are potential endocrine-disrupting compounds that might affect human health. We developed a method for extraction of PFAAs from human serum with simultaneous removal of endogenous sex hormones. The developed method includes solid phase extraction, liquid/liquid extraction, HPLC fractionation and weak anion exchange. The method was validated by extraction of seven persistent PFAAs spiked to human male serum obtaining mean recoveries between 49.6% and 78.6%. Using an estrogen receptor (ER) transactivation luciferase reporter gene assay, analysis of the extracted PFAA serum fraction from three pregnant women showed the ER-active endogenous hormones were removed. The developed method was further documented by extraction of the PFAAs from the serum of 18 Danish pregnant women. The PFAA fraction from three of the 18 samples significantly induced the ER-transactivity. Upon co-exposure with the natural ER-ligand 17β-estradiol (E2), 17 of the 18 PFAA fractions caused a significant further increase of the E2 induced ER-transactivity. In conclusion, we developed a method to extract PFAAs from human serum, and the method documentation suggested that PFAAs at the levels found in human serum can transactivate the ER.

  10. Perfluorinated poly(dimethylsiloxane) via the covalent attachment of perfluoroalkylsilanes on the oxidized surface: Effects on zeta-potential values

    NASA Astrophysics Data System (ADS)

    Sun, Peiling; Horton, J. Hugh

    2013-04-01

    Poly(dimethylsiloxane) (PDMS) is a widely-used polymer in microfluidic devices due to its range of physical and chemical properties suitable for molding micron-sized features. However, its hydrophobicity also leads to some limitations: it poorly supports electro-osmotic flow, and can be incompatible with biomolecules and with many organic solvents. Surface modification is commonly used to vary PDMS surface properties to make it more suitable for specific microfluidic applications. Here, we report on the surface modification of PDMS using perfluoroalkane-triethoxysilanes, via the covalent attachment of triethoxysilane groups on plasma-oxidized PDMS. A device constructed from such fluorinated materials could be used for separating fluorous-tagged proteins or peptides. Modified PDMS were characterized using a range of surface analytical methods. In particular, zeta- (ζ-) potential values at the interfaces of both modified and unmodified PDMS and under varying pH conditions were measured, as ζ-potential is an essential parameter to support electroosmotic flow (EOF), a common pumping method in microfluidic devices. The results showed the length of fluorinated alkane chain has significant effect on the density of surface modifying species and topography following modification. In addition, the perfluorinated modification increases the magnitude of the ζ-potential at the PDMS interface when compared to that of native PDMS, increasing the electro-osmotic flow rate, over a wide pH range. The modified surface is resistant to the diffusion of PDMS oligomers that affects other PDMS surface modification processes.

  11. Perfluorinated acids in air, rain, snow, surface runoff, and lakes: relative importance of pathways to contamination of urban lakes.

    PubMed

    Kim, Seung-Kyu; Kannan, Kurunthachalam

    2007-12-15

    Concentrations of perfluorinated acids (PFAs) were measured in various environmental matrices (air, rain, snow, surface runoff water, and lake water) in an urban area, to enable identification of sources and pathways of PFAs to urban water bodies. Total PFA concentrations ranged from 8.28 to 16.0 pg/ m3 (mean 11.3) in bulk air (sum of vapor and particulate phases), 0.91 to 13.2 ng/L (6.19) in rainwater, 0.91 to 23.9 ng/L (7.98) in snow, 1.11-81.8 ng/L (15.1 ng/L) in surface runoff water (SRW), and 9.49 to 35.9 ng/L (21.8) in lake water. Perfluorooctanoic acid (PFOA) was the predominant compound, accounting for > 35% of the total PFA concentrations, in all environmental matrices analyzed. Concentrations and relative compositions of PFAs in SRW were similar to those found for urban lakes. SRW contributes to contamination by PFOA in urban lakes. The measured concentration ratios of FTOH to PFOA in air were 1-2 orders of magnitude lower than the ratios calculated based on an assumption of exclusive atmospheric oxidation of FTOHs. Nevertheless, the mass balance analysis suggested the presence of an unknown input pathway that could contribute to a significant amount of total PFOA loadings to the lake. Flux estimates of PFOA at the air-water interface in the urban lake suggest net volatilization from water.

  12. TiO2-assisted degradation of a perfluorinated surfactant in aqueous solutions treated by gliding arc discharge.

    PubMed

    Marouf-Khelifa, Kheira; Abdelmalek, Fatiha; Khelifa, Amine; Addou, Ahmed

    2008-02-01

    The plasma-chemical degradation of Forafac 1110, a perfluorinated non-ionic surfactant, in aqueous solutions was investigated using TiO2 catalysts. The considered plasma was the gliding arc in humid air, which results from an electric discharge at atmospheric pressure and quasi-ambient temperature. Two titanium dioxide powders were used and their synergistic effects on the Forafac degradation were compared. The results were discussed through the evolution of the pH, the conductivity, the fluoride ions concentration released in solutions, the surfactant concentration remaining after treatment and the chemical oxygen demand (COD) measurement. The combination of the plasma-chemical treatment with heterogeneous catalysis through the use of TiO2 accelerated the Forafac degradation, since only 60 min was sufficient to remove 96% instead of 360 min needed in the absence of TiO2. The use of anatase and rutile under the trade-name of Rhodia TiO2 and Merck TiO2, respectively, led to different results, because Rhodia TiO2 has proven to be more efficient. It would seem that the crystalline phase as well as the crystallite size, explain the efficiency of anatase. The advantage of the plasma-catalysis is due to the fact that there is a significant production of the OH* radicals not only generated by the gliding arc discharge but also by TiO2.

  13. Perfluorinated alkyl substances in serum of the southern Chinese general population and potential impact on thyroid hormones

    NASA Astrophysics Data System (ADS)

    Li, Yangjie; Cheng, Yating; Xie, Zhiyong; Zeng, Feng

    2017-02-01

    In this study, eight perfluorinated alkyl substances (PFASs) and five thyroid hormones (TSH, FT4, FT3, TGAb, and TMAb) were determined in 202 human serum samples of the general population of Guangdong, Guangxi and Hainan provinces in southern China. Σ8PFASs concentrations ranged from 0.85 to 24.3 ng/mL with a mean value of 4.66 ng/mL. The PFASs composition profiles of human serum samples nearly make no difference at different locations. A significant increase was observed for ∑8PFASs, PFOS, and PFHxS concentrations with age (p < 0.01). Gender-related differences were found; PFOS, PFHxS, PFBS, and PFOA levels were higher in males (p < 0.05), and the mean concentration of ∑8PFASs was 1.5 times greater in males (6.02 ng/mL) than in females (4.15 ng/mL). PFOS and ∑8PFASs were significantly negatively correlated with FT3 and FT4 and positively correlated with TSH while PFPeA and PFHxA were significantly positively correlated with TGAb and TMAb in all the samples. The opposite associations between FT3, TSH and PFOS, PFOA and PFHxS levels in hypothyroidism and hyperthyroidism group indicate that the PFOS, PFOA and PFHxS enhance the negative feedback mechanisms of the thyroid gland.

  14. Spatial and temporal patterns in concentrations of perfluorinated compounds in bald eagle nestlings in the upper Midwestern United States.

    PubMed

    Route, William T; Russell, Robin E; Lindstrom, Andrew B; Strynar, Mark J; Key, Rebecca L

    2014-06-17

    Perfluorinated chemicals (PFCs) are of concern due to their widespread use, persistence in the environment, tendency to accumulate in animal tissues, and growing evidence of toxicity. Between 2006 and 2011 we collected blood plasma from 261 bald eagle nestlings in six study areas from the upper Midwestern United States. Samples were assessed for levels of 16 different PFCs. We used regression analysis in a Bayesian framework to evaluate spatial and temporal trends for these analytes. We found levels as high as 7370 ng/mL for the sum of all 16 PFCs (∑PFCs). Perfluorooctanesulfonate (PFOS) and perfluorodecanesulfonate (PFDS) were the most abundant analytes, making up 67% and 23% of the PFC burden, respectively. Levels of ∑PFC, PFOS, and PFDS were highest in more urban and industrial areas, moderate on Lake Superior, and low on the remote upper St. Croix River watershed. We found evidence of declines in ∑PFCs and seven analytes, including PFOS, PFDS, and perfluorooctanoic acid (PFOA); no trend in two analytes; and increases in two analytes. We argue that PFDS, a long-chained PFC with potential for high bioaccumulation and toxicity, should be considered for future animal and human studies.

  15. Binary fluorous alkylation of biogenic primary amines with perfluorinated aldehyde followed by fluorous liquid chromatography-tandem mass spectrometry analysis.

    PubMed

    Hayama, Tadashi; Sakaguchi, Yohei; Yoshida, Hideyuki; Itoyama, Miki; Todoroki, Kenichiro; Yamaguchi, Masatoshi; Nohta, Hitoshi

    2012-10-02

    We have developed a novel method for the determination of biogenic amines (dopamine, norepinephrine, 3-methoxytyramine, normetanephrine, serotonin, tyramine, tryptamine, 5-methoxytryptamine, and histamine) utilizing liquid chromatography with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) combined with a separation-oriented derivatization technique. Using this approach, primary amino groups in the target amines were selectively dialkylated with a perfluorinated aldehyde reagent (2H,2H,3H,3H-perfluoroundecan-1-al) through reductive amination. The derivatives were directly injected onto an LC column containing perfluoroalkyl-modified stationary phase and were separated via gradient elution using a water/methanol/trifluoroacetic acid mixture and trifluoroethanol with formic acid as mobile phases. Matrix-induced signal suppression effects were eliminated because the binary fluorous-labeled amines were strongly retained on the fluorous-phase LC column, whereas the nonfluorous derivatives, including matrix components and monofluorous-labeled compounds such as the derivatization reagent, were poorly retained under the separation conditions. The linear dynamic ranges of the target amines were established over a concentration range of 0.01-1 nM (r > 0.9978), and the limits of detection were found to be 7.8-26 amol on column. The feasibility of this method was further evaluated by applying it to human plasma samples.

  16. Slippery liquid-infused porous surface based on perfluorinated lubricant/iron tetradecanoate: Preparation and corrosion protection application

    NASA Astrophysics Data System (ADS)

    Yang, Shengsheng; Qiu, Ri; Song, Hongqing; Wang, Peng; Shi, Zhiqiang; Wang, Yanfang

    2015-02-01

    Corrosion and fouling have been two major enemies for materials immersed in seawater. Fluid including gas and liquid as coating for marine corrosion protection has attracted much attention, since it can also exert antifouling capability in seawater environment. Combining gas and solid phases, superhydrophobic surface is promising to protect the underlying metal from corrosion. However, the intrinsically short sustainability in underwater environment has hindered its practical application, so that its corrosion protection ability is only temporary. Originated from liquid and solid phases, slippery liquid-infused porous surface (SLIPS) has spurred wide interest due to its prominent performance in different fields. However, the exploration of corrosion protection efficiency from SLIPS remains rare. In this research, SLIPS is constructed onto steel surface via a facile two-step protocol. First, based on a dissolution-deposition strategy, iron tetradecanoate is formed by an electrochemical route. After that, fluid lubricant is infused onto the deposit, whose rough surface acts as the reservoir to entrap the fluid to form a static liquid coating. Compared to the bare and hydrophobic deposit covering low alloy steel, the SLIPS composed perfluorinated lubricant and iron tetradecanoate endows good corrosion protection property.

  17. First-flush loads of perfluorinated compounds in stormwater runoff from Hayabuchi River basin, Japan served by separated sewerage system.

    PubMed

    Zushi, Yasuyuki; Masunaga, Shigeki

    2009-08-01

    Worldwide environmental pollution by perfluorinated compounds (PFCs) has been reported. PFCs have also been reported to have nonpoint sources (NPSs). A fixed-point hourly monitoring in the river was conducted during a storm event using an automatic sampler to estimate the impact of the first-flush of PFCs from NPS in this study. Perfluorocarboxylates (PFCAs) and perfluoroalkyl sulfonates (PFASs) with different chain lengths were monitored. The concentrations of short- to medium-chain-length PFCAs such as PFHpA, PFOA and PFNA, and PFASs such as PFBS, PFPeS, PFHxS, PFHpS and PFOS showed no marked increase with the storm-runoff event. However, in contrast to this, concentrations of long-chain-length PFCAs such as PFDA and PFUnA increased markedly. The concentrations of PFDA and PFUnA increased 3.4 (1.5-5.0 ng L(-1))- and 2.0 (3.3-6.7 ng L(-1))-fold, respectively. This study demonstrates that large loads of long-chain-length PFCAs are discharged to the Hayabuchi River during the first-flush after the rain event.

  18. Complete Defluorination of Perfluorinated Compounds by Hydrated Electrons Generated from 3-Indole-acetic-acid in Organomodified Montmorillonite

    NASA Astrophysics Data System (ADS)

    Tian, Haoting; Gao, Juan; Li, Hui; Boyd, Stephen A.; Gu, Cheng

    2016-09-01

    Here we describe a unique process that achieves complete defluorination and decomposition of perfluorinated compounds (PFCs) which comprise one of the most recalcitrant and widely distributed classes of toxic pollutant chemicals found in natural environments. Photogenerated hydrated electrons derived from 3-indole-acetic-acid within an organomodified clay induce the reductive defluorination of co-sorbed PFCs. The process proceeds to completion within a few hours under mild reaction conditions. The organomontmorillonite clay promotes the formation of highly reactive hydrated electrons by stabilizing indole radical cations formed upon photolysis, and prevents their deactivation by reaction with protons or oxygen. In the constrained interlayer regions of the clay, hydrated electrons and co-sorbed PFCs are brought in close proximity thereby increasing the probability of reaction. This novel green chemistry provides the basis for in situ and ex situ technologies to treat one of the most troublesome, recalcitrant and ubiquitous classes of environmental contaminants, i.e., PFCs, utilizing innocuous reagents, naturally occurring materials and mild reaction conditions.

  19. Exposure to perfluorinated compounds in Catalonia, Spain, through consumption of various raw and cooked foodstuffs, including packaged food.

    PubMed

    Jogsten, Ingrid Ericson; Perelló, Gemma; Llebaria, Xavier; Bigas, Esther; Martí-Cid, Roser; Kärrman, Anna; Domingo, José L

    2009-07-01

    In this study, the role that some food processing and packaging might play as a source of perfluorinated compounds (PFCs) through the diet was assessed. The levels of PFCs were determined in composite samples of veal steak (raw, grilled, and fried), pork loin (raw, grilled, and fried), chicken breast (raw, grilled, and fried), black pudding (uncooked), liver lamb (raw), marinated salmon (home-made and packaged), lettuce (fresh and packaged), pate of pork liver, foie gras of duck, frankfurt, sausages, chicken nuggets (fried), and common salt. Among the 11 PFCs analyzed, only PFHxS, PFOS, PFHxA, and PFOA were detected in at least one composite sample, while the levels of the remaining PFCs (PFBuS, PFHpA, PFNA, PFDA, PFUnDA, and PFDoDA) were under their respective detection limits. PFOS was the compound most frequently detected, being found in 8 of the 20 food items analyzed, while PFHxA was detected in samples of raw veal, chicken nuggets, frankfurt, sausages, and packaged lettuce. According to the results of the present study, it is not sufficiently clear if cooking with non-stick cookware, or packaging some foods, could contribute to a higher human exposure to PFCs.

  20. Spatial and temporal patterns in concentrations of perfluorinated compounds in bald eagle nestlings in the Upper Midwestern United States

    USGS Publications Warehouse

    Route, William T.; Russell, Robin E.; Lindstrom, Andrew B.; Strynor, Mark J.; Key, Rebecca L.

    2014-01-01

    Perfluorinated chemicals (PFCs) are of concern due to their widespread use, persistence in the environment, tendency to accumulate in animal tissues, and growing evidence of toxicity. Between 2006 and 2011 we collected blood plasma from 261 bald eagle nestlings in six study areas from the upper Midwestern United States. Samples were assessed for levels of 16 different PFCs. We used regression analysis in a Bayesian framework to evaluate spatial and temporal trends for these analytes. We found levels as high as 7370 ng/mL for the sum of all 16 PFCs (∑PFCs). Perfluorooctanesulfonate (PFOS) and perfluorodecanesulfonate (PFDS) were the most abundant analytes, making up 67% and 23% of the PFC burden, respectively. Levels of ∑PFC, PFOS, and PFDS were highest in more urban and industrial areas, moderate on Lake Superior, and low on the remote upper St. Croix River watershed. We found evidence of declines in ∑PFCs and seven analytes, including PFOS, PFDS, and perfluorooctanoic acid (PFOA); no trend in two analytes; and increases in two analytes. We argue that PFDS, a long-chained PFC with potential for high bioaccumulation and toxicity, should be considered for future animal and human studies.

  1. GIS-based source identification and apportionment of diffuse water pollution: perfluorinated compound pollution in the Tokyo Bay basin.

    PubMed

    Zushi, Yasuyuki; Masunaga, Shigeki

    2011-11-01

    To efficiently reduce perfluorinated compound (PFC) pollution, it is important to have an understanding of PFC sources and their contribution to the pollution. In this study, source identification of diffuse water pollution by PFCs was conducted using a GIS-based approach. Major components of the source identification were collection of the monitoring data and preparation of the corresponding geographic information that was extracted from a constructed GIS database. The spatially distributed pollution factors were then explored by multiple linear regression analysis, after which they were visually expressed using GIS. Among the 35 PFC homologues measured in a survey of the Tokyo Bay basin, 18 homologues were analyzed. Pollution by perfluorooctane sulfonate (PFOS) was explained well by the percentage of arterial traffic area in the basin, and the 84% variance of the measured PFOS concentration was explained by two geographic variables, arterial traffic area and population. Source apportionment between point and nonpoint sources was conducted based on the results of the analysis. The contribution of PFOS from nonpoint sources was comparable to that from point sources in several major rivers flowing into Tokyo Bay. Source identification and apportionment using the GIS-based approach was shown to be effective, especially for ubiquitous types of pollution, such as PFC pollution.

  2. Perfluorinated compound concentrations in great blue heron eggs near St. Paul, Minnesota, USA, in 1993 and 2010-2011.

    PubMed

    Custer, Thomas W; Dummer, Paul M; Custer, Christine M; Wu, Qian; Kannan, Kurunthachalam; Trowbridge, Annette

    2013-04-01

    A great blue heron (Ardea herodias) colony on Pig's Eye Island on the Mississippi River near St. Paul, Minnesota, USA, is located near several potential perfluorinated compound (PFC) sources. The PFC concentrations in great blue heron eggs reported from a 1993 collection from the Pig's Eye colony were among the highest measured in bird eggs worldwide. The objective of this investigation was to determine whether PFC concentrations in great blue heron eggs at the Pig's Eye colony have changed since 1993. Total PFC concentrations in great blue heron eggs collected at the Pig's Eye colony in 2010 and 2011 (geometric mean=340 and 492 ng/g wet wt) were 60% lower than the 1993 collection (1,015 ng/g wet wt). Among PFCs, perfluoroalkyl sulfonate concentrations were lower and perfluoroalkyl carboxylate concentrations were higher in the 2010 and 2011 collections. Two of 20 (10%) of the eggs analyzed from Pig's Eye in 2010 and 2011 were >1,000 ng PFCs/g wet weight and the maximum PFC value (2,506 ng PFCs/g wet wt) measured in 2010 and 2011 was among the highest PFC concentration reported in bird eggs. These high concentrations are at levels associated with physiological and neurological effects in birds.

  3. Perfluorinated compound concentrations in great blue heron eggs near St. Paul, Minnesota, USA, in 1993 and 2010-2011

    USGS Publications Warehouse

    Custer, Thomas W.; Dummer, Paul M.; Custer, Christine M.; Wu, Qian; Kannan, Kurunthachalam; Trowbridge, Annette

    2013-01-01

    A great blue heron (Ardea herodias) colony on Pig's Eye Island on the Mississippi River near St. Paul, Minnesota, USA, is located near several potential perfluorinated compound (PFC) sources. The PFC concentrations in great blue heron eggs reported from a 1993 collection from the Pig's Eye colony were among the highest measured in bird eggs worldwide. The objective of this investigation was to determine whether PFC concentrations in great blue heron eggs at the Pig's Eye colony have changed since 1993. Total PFC concentrations in great blue heron eggs collected at the Pig's Eye colony in 2010 and 2011 (geometric mean = 340 and 492 ng/g wet wt) were 60% lower than the 1993 collection (1,015 ng/g wet wt). Among PFCs, perfluoroalkyl sulfonate concentrations were lower and perfluoroalkyl carboxylate concentrations were higher in the 2010 and 2011 collections. Two of 20 (10%) of the eggs analyzed from Pig's Eye in 2010 and 2011 were >1,000 ng PFCs/g wet weight and the maximum PFC value (2,506 ng PFCs/g wet wt) measured in 2010 and 2011 was among the highest PFC concentration reported in bird eggs. These high concentrations are at levels associated with physiological and neurological effects in birds.

  4. Identification, Tissue Distribution, and Bioaccumulation Potential of Cyclic Perfluorinated Sulfonic Acids Isomers in an Airport Impacted Ecosystem.

    PubMed

    Wang, Yuan; Vestergren, Robin; Shi, Yali; Cao, Dong; Xu, Lin; Cai, Yaqi; Zhao, Xiaoli; Wu, Fengchang

    2016-10-18

    The use of cyclic perfluoroalkyl acids as anticorrosive agents in hydraulic fluids remains a poorly characterized source of organofluorine compounds to the environment. Here, we investigated the presence of perfluoroethylenecyclohexanesulfonate (PFECHS) isomers in environmental samples for the first time using a combination of high resolution and tandem mass spectrometry. Five distinct peaks attributed to different isomers of PFECHS and perfluoropropylcyclopentanesulfonate (PFPCPeS) were identified in environmental samples. The sum of PFECHS and PFPCPeS isomers displayed logarithmically decreasing spatial trends in water (1.04-324 ng/L) and sediment samples (perfluorinated acids it is suggested that contamination of aquifers used for drinking water around airports may be a hitherto overlooked problem for this novel class of contaminants.

  5. Analysis of perfluorinated phosponic acids and perfluorooctane sulfonic acid in water, sludge and sediment by LC-MS/MS.

    PubMed

    Esparza, X; Moyano, E; de Boer, J; Galceran, M T; van Leeuwen, S P J

    2011-10-30

    Residues of perfluorinated phosphonic acids (PFPAs) and perfluorooctane sulfonic acid (PFOS) were investigated in various Dutch surface waters, sludge and sediments. For this purpose, a liquid chromatographic (LC) method was optimized by testing several columns with different mobile phases. Atmospheric pressure chemical ionization (APCI) was chosen for the LC tandem mass spectrometry (MS/MS) analysis. An ion-pair reagent was added to the injection solvent to improve peak shape. Different solvents were studied for the extraction from solid samples. For clean-up and pre-concentration, weak anion-exchange solid-phase extraction cartridges were used. Water samples were extracted using the same cartridges. The method was used for screening PFPAs in the Dutch aquatic environment. PFPAs were not observed in sediment or sludge samples. PFOPA was found at 1 ng L(-1) in one surface water sample. PFOS was found at levels between 0.07 ng g(-1) and 48 ng g(-1) (dry weight) in sediments and sewage sludge samples. PFOS concentrations in surface water ranged from 3.3 ng L(-1) to 25.4 ng L(-1).

  6. Estimated pKa values for the environmentally relevant C1 through C8 perfluorinated sulfonic acid isomers.

    PubMed

    Rayne, Sierra; Forest, Kaya

    2016-10-14

    In order to estimate isomer-specific acidity constants (pKa) for the perfluorinated sulfonic acid (PFSA) environmental contaminants, the parameterization method 6 (PM6) pKa prediction method was extensively validated against a wide range of carbon oxyacids and related sulfonic/sulfinic acids. Excellent pKa prediction performance was observed for the carbon oxyacids using the PM6 method, but this approach was found to have a severe positive bias for sulfonic/sulfinic acids. To overcome this obstacle, a correlation was developed between non-adjusted PM6 pKa values and the corresponding experimentally obtained/estimated acidity constants for a range of representative alkyl, aryl and halogen-substituted sulfonic acids. Application of this correction to the PM6 values allows for extension of this computational method to a new acid functional group. When used to estimate isomer-specific pKa values for the C1 through C8 PFSAs, the modified PM6 approach suggests an adjusted pKa range from -5.3 to -9.0, indicating that all members of this class of well-known environmental contaminants will be effectively completely dissociated in aquatic systems.

  7. Characterization of the thermolysis products of Nafion membrane: A potential source of perfluorinated compounds in the environment

    NASA Astrophysics Data System (ADS)

    Feng, Mingbao; Qu, Ruijuan; Wei, Zhongbo; Wang, Liansheng; Sun, Ping; Wang, Zunyao

    2015-05-01

    The thermal decomposition of Nafion N117 membrane, a typical perfluorosulfonic acid membrane that is widely used in various chemical technologies, was investigated in this study. Structural identification of thermolysis products in water and methanol was performed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS). The fluoride release was studied using an ion-chromatography system, and the membrane thermal stability was characterized by thermogravimetric analysis. Notably, several types of perfluorinated compounds (PFCs) including perfluorocarboxylic acids were detected and identified. Based on these data, a thermolysis mechanism was proposed involving cleavage of both the polymer backbone and its side chains by attack of radical species. This is the first systematic report on the thermolysis products of Nafion by simulating its high-temperature operation and disposal process via incineration. The results of this study indicate that Nafion is a potential environmental source of PFCs, which have attracted growing interest and concern in recent years. Additionally, this study provides an analytical justification of the LC/ESI-MS/MS method for characterizing the degradation products of polymer electrolyte membranes. These identifications can substantially facilitate an understanding of their decomposition mechanisms and offer insight into the proper utilization and effective management on these membranes.

  8. Accumulation of perfluorinated compounds in captive Bengal tigers (Panthera tigris tigris) and African lions (Panthera leo Linnaeus) in China.

    PubMed

    Li, Xuemei; Yeung, Leo Wai Yin; Taniyasu, Sachi; Lam, Paul K S; Yamashita, Nobuyoshi; Xu, Muqi; Dai, Jiayin

    2008-11-01

    The accumulation of perfluorinated compounds (PFCs) in the sera of captive wildlife species Bengal tigers (Panthera tigris tigris) and African lions (Panthera leo Linnaeus) from Harbin Wildlife Park, Heilongjiang Province, in China were analyzed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Perfluorooctanesulfonate (PFOS) was the predominant contaminant with a mean serum concentration of 1.18 ng mL(-1) in tigers and 2.69 ng mL(-1) in lions. Perfluorononanoic acid (PFNA) was the second most prevalent contaminant in both species. The composition profiles of the tested PFCs differed between tigers and lions, and the percentages of perfluorooctanoic acid (PFOA) were greater in lions than in tigers, indicating different exposures and/or metabolic capabilities between the two species. Assessments of the risk of PFC contamination to the two species were obtained by comparing measured concentrations to points of departure or toxicity reference values (TRVs). Results suggest no risk of PFOS exposure or toxicity for the two species.

  9. Complete Defluorination of Perfluorinated Compounds by Hydrated Electrons Generated from 3-Indole-acetic-acid in Organomodified Montmorillonite

    PubMed Central

    Tian, Haoting; Gao, Juan; Li, Hui; Boyd, Stephen A.; Gu, Cheng

    2016-01-01

    Here we describe a unique process that achieves complete defluorination and decomposition of perfluorinated compounds (PFCs) which comprise one of the most recalcitrant and widely distributed classes of toxic pollutant chemicals found in natural environments. Photogenerated hydrated electrons derived from 3-indole-acetic-acid within an organomodified clay induce the reductive defluorination of co-sorbed PFCs. The process proceeds to completion within a few hours under mild reaction conditions. The organomontmorillonite clay promotes the formation of highly reactive hydrated electrons by stabilizing indole radical cations formed upon photolysis, and prevents their deactivation by reaction with protons or oxygen. In the constrained interlayer regions of the clay, hydrated electrons and co-sorbed PFCs are brought in close proximity thereby increasing the probability of reaction. This novel green chemistry provides the basis for in situ and ex situ technologies to treat one of the most troublesome, recalcitrant and ubiquitous classes of environmental contaminants, i.e., PFCs, utilizing innocuous reagents, naturally occurring materials and mild reaction conditions. PMID:27608658

  10. Application of WWTP biosolids and resulting perfluorinated compound contamination of surface and well water in Decatur, Alabama, USA.

    PubMed

    Lindstrom, Andrew B; Strynar, Mark J; Delinsky, Amy D; Nakayama, Shoji F; McMillan, Larry; Libelo, E Laurence; Neill, Michael; Thomas, Lee

    2011-10-01

    Perfluorinated chemicals (PFCs) such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been produced and used in a wide range of industrial and consumer products for many decades. Their resistance to degradation has led to their widespread distribution in the environment, but little is known about how humans become exposed. Recent studies have demonstrated that the application of PFC contaminated biosolids can have important effects on local environments, ultimately leading to demonstrable human exposures. This manuscript describes a situation in Decatur, Alabama where PFC contaminated biosolids from a local municipal wastewater treatment facility that had received waste from local fluorochemical facilities were used as a soil amendment in local agricultural fields for as many as twelve years. Ten target PFCs were measured in surface and groundwater samples. Results show that surface and well water in the vicinity of these fields had elevated PFC concentrations, with 22% of the samples exceeding the U.S. Environmental Protection Agency's Provisional Health Advisory level for PFOA in drinking water of 400 ng/L. Water/soil concentration ratios as high as 0.34 for perfluorohexanoic acid, 0.17 for perfluoroheptanoic acid, and 0.04 for PFOA verify decreasing mobility from soils with increasing chain length while indicating that relatively high transport from soils to surface and well water is possible.

  11. Relative importance of wastewater treatment plants and non-point sources of perfluorinated compounds to Washington State rivers.

    PubMed

    Furl, Chad V; Meredith, Callie A; Strynar, Mark J; Nakayama, Shoji F

    2011-07-01

    Perfluorinated compounds (PFCs) were measured in 10 Washington State rivers and 4 wastewater treatment plants (WWTPs) under periods of low and high flows to investigate the relative importance of point and non-point sources to rivers. PFCs were detected in all samples with summed values ranging from 1.11 to 74.9 ng/L in surface waters and 62.3-418 ng/L in WWTP effluent. Concentrations in 6 of the 10 rivers exhibited a positive relationship with flow, indicating runoff as a contributing source, with PFC loads greatest at all 10 waterbodies during high flows. Perfluoroheptanoic acid:perfluorooctanoic acid homologue ratios suggest atmospheric contributions to the waterbodies are important throughout the year. Principal component analysis (PCA) indicated distinct homologue profiles for high flow, low flow, and effluent samples. The PCA demonstrates that during the spring when flows and loads are at their greatest; WWTP discharges are not the primary sources of PFCs to the river systems. Taken together, the evidence provided signifies non-point inputs are a major pathway for PFCs to surface waters in Washington State.

  12. Concentrations and trends of perfluorinated chemicals in potential indoor sources from 2007 through 2011 in the US.

    PubMed

    Liu, Xiaoyu; Guo, Zhishi; Krebs, Kenneth A; Pope, Robert H; Roache, Nancy F

    2014-03-01

    Certain perfluorinated chemicals (PFCs) in consumer products used indoors are potential indoor PFCs sources and have been associated with developmental toxicity and other adverse health effects in laboratory animals (Lao et al., 2007). The concentrations of selected PFCs including perfluorooctanoic acid (PFOA) and other perfluorocarboxylic acids (PFCAs), in 35 selected consumer products that are commonly used in indoors were measured from the year of 2007 through 2011. The products collected included carpet, commercial carpet-care liquids, household carpet/fabric-care liquids, treated apparel, treated home textiles, treated non-woven medical garments, floor waxes, food-contact paper, membranes for apparel, and thread-sealant tapes. They were purchased from retail outlets in the United States between March 2007 and September 2011. The perfluorocarboxylic acid (PFCA) contents in the products have shown an overall downward trend. However, PFOA (C8) could still be detected in many products that we analyzed. Reductions of PFCAs were shown in both short-chain PFCAs (sum of C4 to C7) and long-chain PFCAs (sum of C8 to C12) over the study period. There were no significant changes observed between short-chain PFCAs and long-chain PFCAs. Fourteen products were analyzed to determine the amounts of perfluoroalkyl sulfonates (PFASs) they contained. These limited data show the pronounced increase of perfluoro-butane sulfonate (PFBS), an alternative to perfluorooctanoic sulfonate (PFOS), in the samples. A longer and wider range of study will be required to confirm this observed trend.

  13. Ion-pair sorptive extraction of perfluorinated compounds from water with low-cost polymeric materials: polyethersulfone vs polydimethylsiloxane.

    PubMed

    Villaverde-de-Sáa, Eugenia; Racamonde, Inés; Quintana, José Benito; Rodil, Rosario; Cela, Rafael

    2012-08-31

    A method for the determination of seven perfluorinated carboxylic acids and perfluorooctane sulphonate (PFOS) in aqueous samples using low-cost polymeric sorptive extraction as sample preparation technique, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination has been developed and validated. Simplicity of the analytical procedure, low volume of solvent and sample required, low global price and a good selectivity providing cleaner extracts are the main advantages of this extraction technique. Polydimethylsiloxane (PDMS) and polyethersulfone (PES) materials were evaluated and compared to achieve the best extraction efficiencies. Hence, different variables have been optimized, viz.: sample pH, concentration of an ion-pairing agent (tetrabutylammonium), ionic strength, sample volume, extraction time, desorption solvent volume, desorption time and the need for auxiliary desorption techniques (sonication). Overall, PES leaded to a better sensitivity than PDMS, particularly for the most polar compounds, reaching detection limits (LODs) in the 0.2-20 ng L(-1) range. The precision of the method, expressed as relative standard deviation (RSD), was lower than 16%. Finally, the PES material was employed for the analysis of sea, sewage and fresh water samples. Perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were detected in all the analyzed influent samples reaching levels of up to 401 ng L(-1). In surface water, perfluorohexanoic acid (PFHxA) exhibited the highest concentrations, up to 137 ng L(-1).

  14. Fused silica reflecting heat shields for outer planet entry probes

    NASA Technical Reports Server (NTRS)

    Congdon, W. M.; Peterson, D. L.

    1975-01-01

    The development of slip-cast fused silica is discussed as a heat shield designed to meet the needs of outer-planet entry probes. The distinguishing feature of silica is its ability to reflect the radiation imposed by planetary-entry environments. This reflectivity is particularly sensitive to degradation by the presence of trace amounts of contaminants introduced by the starting materials or by processing. The microstructure of a silica configuration also significantly influences the reflectivity and other thermomechanical properties. The processing techniques attendant on controlling microstructure while maintaining purity are discussed. The selection of a starting material of essential purity precludes the use of purified natural quartz and requires the use of synthetic fused silica. The silica is characterized in a limited combined heating test environment. The surface mass loss is controlled by liquid runoff from a relatively low-temperature melt layer; the reflectance is basically maintained and the material achieves a surprisingly high heat of ablation.

  15. HVI Ballistic Limit Charaterization of Fused Silica Thermal Pane

    NASA Technical Reports Server (NTRS)

    Bohl, William E.; Miller, Joshua E.; Christiansen, Eric L.; Deighton, Kevin.; Davis, Bruce

    2015-01-01

    The Orion spacecraft's windows are exposed to the micrometeroid and orbital debris (MMOD) space environments while in space as well as the Earth entry environment at the mission's conclusion. The need for a low-mass spacecraft window design drives the need to reduce conservatism when assessing the design for loss of crew due to MMOD impact and subsequent Earth entry. Therefore, work is underway at NASA and Lockheed Martin to improve characterization of the complete penetration ballistic limit of an outer fused silica thermal pane. Hypervelocity impact tests of the window configuration at up to 10 km/s and hydrocode modeling have been performed with a variety of projectile materials to enable refinement of the fused silica ballistic limit equation.

  16. Mechanical protection of DLC films on fused silica slides

    NASA Technical Reports Server (NTRS)

    Nir, D.

    1985-01-01

    Measurements were made with a new test for improved quantitative estimation of the mechanical protection of thin films on optical materials. The mechanical damage was induced by a sand blasting system using spherical glass beads. Development of the surface damage was measured by the changes in the specular transmission and reflection, and by inspection using a surface profilometer and a scanning electron microscope. The changes in the transmittance versus the duration of sand blasting was measured for uncoated fused silica slides and coated ones. It was determined that the diamond like carbon films double the useful optical lifetime of the fused silica. Theoretical expressions were developed to describe the stages in surface deterioration. Conclusions were obtained for the SiO2 surface mechanism and for the film removal mechanism.

  17. Depth-fused 3D imagery on an immaterial display.

    PubMed

    Lee, Cha; Diverdi, Stephen; Höllerer, Tobias

    2009-01-01

    We present an immaterial display that uses a generalized form of depth-fused 3D (DFD) rendering to create unencumbered 3D visuals. To accomplish this result, we demonstrate a DFD display simulator that extends the established depth-fused 3D principle by using screens in arbitrary configurations and from arbitrary viewpoints. The feasibility of the generalized DFD effect is established with a user study using the simulator. Based on these results, we developed a prototype display using one or two immaterial screens to create an unencumbered 3D visual that users can penetrate, examining the potential for direct walk-through and reach-through manipulation of the 3D scene. We evaluate the prototype system in formative and summative user studies and report the tolerance thresholds discovered for both tracking and projector errors.

  18. The ROC Curves of Fused Independent Classification Systems

    DTIC Science & Technology

    2008-09-01

    spectral settings arises in many fields of study; in medicine, the detection of a cancer; in marketing , the detection of the best customer base; in the...THE ROC CURVES OF FUSED INDEPENDENT CLASSIFICATION SYSTEMS THESIS Michael B. Walsh AFIT/GAM/ENC/08/06 DEPARTMENT OF THE AIR FORCE AIR UNIVERSITY AIR...FORCE INSTITUTE OF TECHNOLOGY Wright-Patterson Air Force Base, Ohio APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. The views expressed in this

  19. Chemical and Biological Sensing Utilizing Fused Bacteriorhodopsin Protein Hybrids

    DTIC Science & Technology

    2008-12-01

    Utilizing this purified DNA and a plasmid expression vector system, a fused protein hybrid consisting of maltose binding protein and bacterio-opsin has...prior to transcription, or post-expression. Therefore, for the development of the current proof of concept biosensor, maltose binding protein has...been chosen for attachment to the N-terminus of bR by genetic fusion and subsequent expression in E. coli. The maltose binding protein is a

  20. 30 CFR 75.601-3 - Short circuit protection; dual element fuses; current ratings; maximum values.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Short circuit protection; dual element fuses... Trailing Cables § 75.601-3 Short circuit protection; dual element fuses; current ratings; maximum values. Dual element fuses having adequate current-interrupting capacity shall meet the requirements for...

  1. 30 CFR 75.601-3 - Short circuit protection; dual element fuses; current ratings; maximum values.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Short circuit protection; dual element fuses... Trailing Cables § 75.601-3 Short circuit protection; dual element fuses; current ratings; maximum values. Dual element fuses having adequate current-interrupting capacity shall meet the requirements for...

  2. 30 CFR 75.601-3 - Short circuit protection; dual element fuses; current ratings; maximum values.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Short circuit protection; dual element fuses... Trailing Cables § 75.601-3 Short circuit protection; dual element fuses; current ratings; maximum values. Dual element fuses having adequate current-interrupting capacity shall meet the requirements for...

  3. Characterization of copper and nichrome wires for safety fuse

    NASA Astrophysics Data System (ADS)

    Murdani, E.

    2016-11-01

    Fuse is an important component of an electrical circuit to limiting the current through the electrical circuit for electrical equipment safety. Safety fuses are made of a conductor such as copper and nichrome wires. The aim of this research was to determine the maximum current that can flow in the conductor wires (copper and nichrome). In the experiment used copper and nichrome wires by varying the length of wires (0.2 cm to 20 cm) and diameter of wires (0.1, 0.2, 0.3, 0.4 and 0.5) mm until maximum current reached that marked by melted or broken wire. From this experiment, it will be obtained the dependences data of maximum current to the length and diameter of wires. All data are plotted and it's known as a standard curve. The standard curve will provide an alternative choice of replacing fuse wire according to the maximum current requirement, including the wire type (copper and nichrome wires) and wire dimensions (length and diameter of wire).

  4. FUSE observations of Hot Gas in the Carina Nebula

    NASA Astrophysics Data System (ADS)

    Iping, R. C.; Sonneborn, G.; Jenkins, E. B.; Bowen, D. V.

    2002-06-01

    We present an analysis of interstellar O VI 1031.93 toward several O and WR stars in the Tr 16 cluster, based on high-resolution spectra obtained with the FUSE satellite. The objective of this study is to investigate the distribution of O VI absorption within the cluster. The target stars include CPD-59D2628, CPD-59D2627, CPD-59D2632, HDE 303308, CPD -59 2600, CPD -59 2603, HD093205, HD093204, HD93162, HD093250 and HD 93308 (Eta Car). Two interstellar molecular hydrogen transitions, Lyman 6-0 P(3) 1031.19 and Lyman 6-0 R(4) 1032.35, are located very close to the interstellar O VI feature. These lines have been modelled by analyzing other P(3) and R(4) transitions in the FUSE spectrum. The column densities and distribution of the O VI ion in the Carina Nebulae is determined by using Gaussian profile fitting procedures. These results are compared with FUSE observations of other OB stars in the general vicinity of Carina, but outside the active region. This work has been supported in part by NASA grants NAG5-11137 to Catholic University of America and NASA contract NAS5-32985 to Johns Hopkins University.

  5. FUSE Observations of the Herbig Be star HD 100546

    NASA Astrophysics Data System (ADS)

    Deleuil, M.; Roberge, A.; Feldman, P. D.; Lecavelier des Etangs, A.; Vidal-Madjar, A.; Bouret, J.-C.; Ferlet, R.; André, M.; Moos, H. W.; Blair, W. P.; FUSE Science Team

    2000-12-01

    The first observation of the Herbig Be star HD100546 in the far UV has been made by the Far Ultraviolet Spectroscopic Explorer (FUSE). The spectra reveal numerous circumstellar absorption lines arising not only from the fine structure levels of refractory species like Fe 2, but also from neutral volatiles: C 1, C 1*, N 1 and N 1*. H2 transitions detected in absorption probe the cold gaseous portion of the circumstellar environment. Strong unexpected emission lines are also observed below 1100 Å, where the stellar continuum flux is very low. In particular, broad C 3 and O 6 emission lines demonstrate the presence of hot, dense, collisionally ionized gas which may be related to an extended chromosphere and/or corona. These features reveal a complex circumstellar environment, with wide range of temperatures and physical conditions. Based on observations obtained for the Guaranteed Time Team by the NASA-CNES-CSA FUSE mission. FUSE is operated for NASA by the John Hopkins University under NASA contract NASS-32985.

  6. Psychophysical assessments of image-sensor fused imagery.

    PubMed

    Krebs, William K; Sinai, Michael J

    2002-01-01

    The goal of this study was to determine the perceptual advantages of multiband sensor-fused (achromatic and chromatic) imagery over conventional single-band nighttime (image-intensified and infrared) imagery for a wide range of visual tasks, including detection, orientation, and scene recognition. Participants were 151 active-duty military observers whose reaction time and accuracy scores were recorded during a visual search task. Data indicate that sensor fusion did not improve performance relative to that obtained with single-band imagery on a target detection task but did facilitate object recognition, judgments of spatial orientation, and scene recognition. Observers' recognition and orientation judgments were improved by the emergent information within the image-fused imagery (i.e., combining dominant information from two or more sensors into a single displayed image). Actual or potential applications of this research include the deployment of image-sensor fused systems for automobile, aviation, and maritime displays to increase operators' visual processing during low-light conditions.

  7. Monolithic Cylindrical Fused Silica Resonators with High Q Factors

    PubMed Central

    Pan, Yao; Wang, Dongya; Wang, Yanyan; Liu, Jianping; Wu, Suyong; Qu, Tianliang; Yang, Kaiyong; Luo, Hui

    2016-01-01

    The cylindrical resonator gyroscope (CRG) is a typical Coriolis vibratory gyroscope whose performance is determined by the Q factor and frequency mismatch of the cylindrical resonator. Enhancing the Q factor is crucial for improving the rate sensitivity and noise performance of the CRG. In this paper, for the first time, a monolithic cylindrical fused silica resonator with a Q factor approaching 8 × 105 (ring-down time over 1 min) is reported. The resonator is made of fused silica with low internal friction and high isotropy, with a diameter of 25 mm and a center frequency of 3974.35 Hz. The structure of the resonator is first briefly introduced, and then the experimental non-contact characterization method is presented. In addition, the post-fabrication experimental procedure of Q factor improvement, including chemical and thermal treatment, is demonstrated. The Q factor improvement by both treatments is compared and the primary loss mechanism is analyzed. To the best of our knowledge, the work presented in this paper represents the highest reported Q factor for a cylindrical resonator. The proposed monolithic cylindrical fused silica resonator may enable high performance inertial sensing with standard manufacturing process and simple post-fabrication treatment. PMID:27483263

  8. High strength fused silica flexures manufactured by femtosecond laser

    NASA Astrophysics Data System (ADS)

    Bellouard, Yves; Said, Ali A.; Dugan, Mark; Bado, Philippe

    2009-02-01

    Flexures are mechanical elements used in micro- and precision-engineering to precisely guide the motion of micro-parts. They consist of slender bodies that deform elastically upon the application of a force. Although counter-intuitive at first, fused silica is an attractive material for flexure. Pending that the machining process does not introduce surface flaws that would lead to catastrophic failure, the material has a theoretically high ultimate tensile strength of several GPa. We report on high-aspect ratio fused silica flexures manufactured by femtosecond laser combined with chemical etching. Notch-hinges with thickness as small as twenty microns and aspect ratios comparable to aspect ratios obtained by Deep- Reactive-Ion-Etching (DRIE) were fabricated and tested under different loading conditions. Multiple fracture tests were performed for various loading conditions and the cracks morphologies were analyzed using Scanning Electron Microscopy. The manufactured elements show outstanding mechanical properties with flexural strengths largely exceeding those obtained with other technologies and materials. Fused silica flexures offer a mean to combine integrated optics with micro-mechanics in a single monolithic substrate. Waveguides and mechanical elements can be combined in a monolithic devices opening new opportunities for integrated opto-mechatronics devices.

  9. A hierarachical data structure representation for fusing multisensor information

    SciTech Connect

    Maren, A.J.; Pap, R.M.; Harston, C.T.

    1989-12-31

    A major problem with MultiSensor Information Fusion (MSIF) is establishing the level of processing at which information should be fused. Current methodologies, whether based on fusion at the data element, segment/feature, or symbolic levels, are each inadequate for robust MSIF. Data-element fusion has problems with coregistration. Attempts to fuse information using the features of segmented data relies on a Presumed similarity between the segmentation characteristics of each data stream. Symbolic-level fusion requires too much advance processing (including object identification) to be useful. MSIF systems need to operate in real-time, must perform fusion using a variety of sensor types, and should be effective across a wide range of operating conditions or deployment environments. We address this problem through developing a new representation level which facilitates matching and information fusion. The Hierarchical Data Structure (HDS) representation, created using a multilayer, cooperative/competitive neural network, meets this need. The HDS is an intermediate representation between the raw or smoothed data stream and symbolic interpretation of the data. it represents the structural organization of the data. Fused HDSs will incorporate information from multiple sensors. Their knowledge-rich structure aids top-down scene interpretation via both model matching and knowledge-based region interpretation.

  10. A hierarachical data structure representation for fusing multisensor information

    SciTech Connect

    Maren, A.J. . Space Inst.); Pap, R.M.; Harston, C.T. )

    1989-01-01

    A major problem with MultiSensor Information Fusion (MSIF) is establishing the level of processing at which information should be fused. Current methodologies, whether based on fusion at the data element, segment/feature, or symbolic levels, are each inadequate for robust MSIF. Data-element fusion has problems with coregistration. Attempts to fuse information using the features of segmented data relies on a Presumed similarity between the segmentation characteristics of each data stream. Symbolic-level fusion requires too much advance processing (including object identification) to be useful. MSIF systems need to operate in real-time, must perform fusion using a variety of sensor types, and should be effective across a wide range of operating conditions or deployment environments. We address this problem through developing a new representation level which facilitates matching and information fusion. The Hierarchical Data Structure (HDS) representation, created using a multilayer, cooperative/competitive neural network, meets this need. The HDS is an intermediate representation between the raw or smoothed data stream and symbolic interpretation of the data. it represents the structural organization of the data. Fused HDSs will incorporate information from multiple sensors. Their knowledge-rich structure aids top-down scene interpretation via both model matching and knowledge-based region interpretation.

  11. Hysteretic Behavior of Proprotein Convertase 1/3 (PC1/3)

    PubMed Central

    Icimoto, Marcelo Y.; Barros, Nilana M.; Ferreira, Juliana C.; Marcondes, Marcelo F.; Andrade, Douglas; Machado, Mauricio F.; Juliano, Maria A.; Júdice, Wagner A.; Juliano, Luiz; Oliveira, Vitor

    2011-01-01

    The proprotein convertases (PCs) are calcium-dependent proteases responsible for processing precursor proteins into their active forms in eukariotes. The PC1/3 is a pivotal enzyme of this family that participates in the proteolytic maturation of prohormones and neuropeptides inside the regulated secretory pathway. In this paper we demonstrate that mouse proprotein convertase 1/3 (mPC1/3) has a lag phase of activation by substrates that can be interpreted as a hysteretic behavior of the enzyme for their hydrolysis. This is an unprecedented observation in peptidases, but is frequent in regulatory enzymes with physiological relevance. The lag phase of mPC1/3 is dependent on substrate, calcium concentration and pH. This hysteretic behavior may have implications in the physiological processes in which PC1/3 participates and could be considered an additional control step in the peptide hormone maturation processes as for instance in the transformation of proinsulin to insulin. PMID:21935423

  12. High-performance fused indium gallium arsenide/silicon photodiode

    NASA Astrophysics Data System (ADS)

    Kang, Yimin

    Modern long haul, high bit rate fiber-optic communication systems demand photodetectors with high sensitivity. Avalanche photodiodes (APDs) exhibit superior sensitivity performance than other types of photodetectors by virtual of its internal gain mechanism. This dissertation work further advances the APD performance by applying a novel materials integration technique. It is the first successful demonstration of wafer fused InGaAs/Si APDs with low dark current and low noise. APDs generally adopt separate absorption and multiplication (SAM) structure, which allows independent optimization of materials properties in two distinct regions. While the absorption material needs to have high absorption coefficient in the target wavelength range to achieve high quantum efficiency, it is desirable for the multiplication material to have large discrepancy between its electron and hole ionization coefficients to reduce noise. According to these criteria, InGaAs and Si are the ideal materials combination. Wafer fusion is the enabling technique that makes this theoretical ideal an experimental possibility. APDs fabricated on the fused InGaAs/Si wafer with mesa structure exhibit low dark current and low noise. Special device fabrication techniques and high quality wafer fusion reduce dark current to nano ampere level at unity gain, comparable to state-of-the-art commercial III/V APDs. The small excess noise is attributed to the large difference in ionization coefficients between electrons and holes in silicon. Detailed layer structure designs are developed specifically for fused InGaAs/Si APDs based on principles similar to those used in traditional InGaAs/InP APDs. An accurate yet straightforward technique for device structural parameters extraction is also proposed. The extracted results from the fabricated APDs agree with device design parameters. This agreement also confirms that the fusion interface has negligible effect on electric field distributions for devices fabricated

  13. IRIS Toxicological Review of Hexahydro-1,3,5-Trinitro-1,3,5 ...

    EPA Pesticide Factsheets

    The IRIS Toxicological Review of Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was released for external peer review in September 2016. The EPA’s Science Advisory Board’s (SAB) Chemical Assessment Advisory Committee (CAAC) will conduct a peer review of the scientific basis supporting the RDX assessment and release a final report of their review. Information regarding the peer review can be found on the SAB website. EPA is undertaking an update of the Integrated Risk Information System (IRIS) health assessment for RDX. The outcome of this project is an updated Toxicological Review and IRIS Summary for RDX that will be entered into the IRIS database.

  14. Microwave assisted synthesis of some new fused 1,2,4-triazines bearing thiophene moieties with expected pharmacological activity.

    PubMed

    Saad, Hosam A; Youssef, Mohamed M; Mosselhi, Mosselhi A

    2011-06-15

    Rapid and efficient solvent-free synthesis of 4-amino-3-mercapto-6-[2-(2-thienyl)vinyl]-1,2,4-triazin-5(4H)-one 1 under microwave irradiation is described. Some new fused heterobicyclic nitrogen systems such as 1,2,4-triazino[3,4-b][1,3,4]thiadiazinones, 1,3,4-thiadiazolo[2,3-c][1,2,4]triazinone and pyrazolo[5,1-c]-[1,2,4]triazine-7-carbonitrile, have been synthesized by treatment of 1 with bifunctional oxygen and halogen compounds, CS₂/KOH and malononitrile via heterocyclization reactions, in addition to some uncondensed triazines. Structures of the products have been deduced from their elemental analysis and spectral data (IR, ¹H-NMR, ¹³C-NMR). Select new synthesized compounds were screened as anticancer agents, with some showing activity as cytotoxic agents against different cancer cell lines.

  15. Ambiphilic properties of SF5CF2CF2Br derived perfluorinated radical in addition reactions across carbon-carbon double bonds.

    PubMed

    Dudziński, Piotr; Matsnev, Andrej V; Thrasher, Joseph S; Haufe, Günter

    2015-03-06

    The extraordinary properties of the pentafluorosulfanyl (SF5) group attract attention of organic chemists. While numerous SF5-substituted compounds have been synthesized, the direct introduction of SF5(CF2)n moieties has remained almost unexplored. Our investigations revealed the ambiphilic character of the SF5CF2CF2 radical. Addition reactions to electron-rich or electron-deficient alkenes profit either from its electrophilic or nucleophilic properties. Thus, the readily available SF5CF2CF2Br proved to be a promising and versatile building block for the introduction of this perfluorinated moiety.

  16. Mitigation of Laser Damage Growth in Fused Silica with a Galvanometer Scanned CO2 Laser

    SciTech Connect

    Bass, I L; Guss, G M; Hackel, R P

    2005-10-28

    At the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL), mitigation of laser surface damage growth on fused silica using single and multiple CO{sub 2} laser pulses has been consistently successful for damage sites whose lateral dimensions are less than 100 {micro}m, but has not been for larger sites. Cracks would often radiate outward from the damage when a CO{sub 2} pulse was applied to the larger sites. An investigation was conducted to mitigate large surface damage sites using galvanometer scanning of a tightly focused CO{sub 2} laser spot over an area encompassing the laser damage. It was thought that by initially scanning the CO{sub 2} spot outside the damage site, radiating crack propagation would be inhibited. Scan patterns were typically inward moving spirals starting at radii somewhat larger than that of the damage site. The duration of the mitigation spiral pattern was {approx}110 ms during which a total of {approx}1.3 J of energy was delivered to the sample. The CO{sub 2} laser spot had a 1/e{sup 2}-diameter of {approx}200 {micro}m. Thus, there was general heating of a large area around the damage site while rapid evaporation occurred locally at the laser spot position in the spiral. A 30 to 40 {micro}m deep crater was typically generated by this spiral with a diameter of {approx}600 {micro}m. The spiral would be repeated until there was no evidence of the original damage in microscope images. Using this technique, damage sites as large as 300 mm in size did not display new damage after mitigation when exposed to fluences exceeding 22 J/cm{sup 2} at 355 nm, 7.5 ns. It was found necessary to use a vacuum nozzle during the mitigation process to reduce the amount of re-deposited fused silica. In addition, curing spiral patterns at lower laser powers were used to presumably ''re-melt'' any re-deposited fused silica. A compact, shearing interferometer microscope was developed to permit in situ measurement of the depth of

  17. Perfluorinated compounds differentially affect steroidogenesis and viability in the human adrenocortical carcinoma (H295R) in vitro cell assay.

    PubMed

    Kraugerud, Marianne; Zimmer, Karin E; Ropstad, Erik; Verhaegen, Steven

    2011-08-10

    Perfluorinated compounds (PFCs) comprise a large class of man-made chemicals of which some are persistent and present throughout the ecosystem. This raises concerns about potential harmful effects of such PFCs on humans and the environment. In order to investigate the effects of potentially harmful PFCs on steroid hormone production, human adrenocortical H295R cells were exposed to three persistent PFCs including perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) at six different concentrations (6nM to 600μM) for 48h. Exposure to 600μM PFOS resulted in a dose-responsive increase in oestradiol as well as a smaller dose-responsive increase in progesterone and testosterone secretion measured using radioimmunoassay. The aromatase activity was not significantly altered by PFOS. Only small changes in hormone secretion were detected following exposure to PFOA and PFNA. Gene expression of CYP11A, quantified using qRT-PCR was decreased by all exposure doses of PFOA, whereas HMGR expression was decreased by 60nM PFNA. The viability markedly decreased by exposure to 600μM of PFOA or PFNA, but not PFOS. Flow cytometric analysis demonstrated a significant increase in apoptosis following exposure to PFNA at the highest concentration. We conclude that PFOS is capable of altering steroidogenesis in the H295R in vitro model by a mechanism other than changes in gene expression or activity of aromatase. Additionally, PFCs appear to differentially affect cell viability with induction of cell death via apoptosis at high doses of PFNA.

  18. Fragmentation and reactivity in collisions of protonated diglycine with chemically modified perfluorinated alkylthiolate-self-assembled monolayer surfaces

    SciTech Connect

    Barnes, George L.; Yang Li; Hase, William L.; Young, Kelsey

    2011-03-07

    Direct dynamics simulations are reported for quantum mechanical (QM)/molecular mechanical (MM) trajectories of N-protonated diglycine (gly{sub 2}-H{sup +}) colliding with chemically modified perfluorinated octanethiolate self-assembled monolayer (SAM) surfaces. The RM1 semiempirical theory is used for the QM component of the trajectories. RM1 activation and reaction energies were compared with those determined from higher-level ab initio theories. Two chemical modifications are considered in which a head group (-COCl or -CHO) is substituted on the terminal carbon of a single chain of the SAM. These surfaces are designated as the COCl-SAM and CHO-SAM, respectively. Fragmentation, peptide reaction with the SAM, and covalent linkage of the peptide or its fragments with the SAM surface are observed. Peptide fragmentation via concerted CH{sub 2}-CO bond breakage is the dominant pathway for both surfaces. HCl formation is the dominant species produced by reaction with the COCl-SAM, while for the CHO-SAM a concerted H-atom transfer from the CHO-SAM to the peptide combined with either a H-atom or radical transfer from the peptide to the surface to form singlet reaction products is the dominant pathway. A strong collision energy dependence is found for the probability of peptide fragmentation, its reactivity, and linkage with the SAM. Surface deposition, i.e., covalent linkage between the surface and the peptide, is compared to recent experimental observations of such bonding by Laskin and co-workers [Phys. Chem. Chem. Phys. 10, 1512 (2008)]. Qualitative differences in reactivity are seen between the COCl-SAM and CHO-SAM showing that chemical identity is important for surface reactivity. The probability of reactive surface deposition, which is most closely analogous to experimental observables, peaks at a value of around 20% for a collision energy of 50 eV.

  19. Determination of perfluorinated compounds (PFCs) in solid and liquid phase river water samples in Chao Phraya River, Thailand.

    PubMed

    Kunacheva, Chinagarn; Tanaka, Shuhei; Fujii, Shigeo; Boontanon, Suwanna Kitpati; Musirat, Chanatip; Wongwattana, Thana

    2011-01-01

    Perfluorinated compounds (PFCs), especially perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are fully fluorinated organic compounds, which have been used in many industrial applications. These chemicals have contaminated surface water all over the world even in developing countries like Thailand. The previous study showed the contamination in Chao Phraya River in 2006 and 2007. The purposes of this field study were to determine the solid and liquid phase of PFCs contamination in Chao Phraya River and to compare the changes of PFC concentration in 2008. Surveys were conducted in the lower reach of Chao Phraya River in the industrialized area. A solid phase extraction (SPE) coupled with HPLC-ESI-MS/MS were used for the analysis for ten PFCs. Ten PFCs were analyzed to identify the contamination in both solid and liquid phases. PFCs were detected in both the solid and liquid phase in every sample. PFOA was the most dominant PFC while PFPA and PFOS were also highly detected in most samples. The average loadings of PFPA, PFOA and PFOS in Chao Phraya River were 94.3, 284.6 and 93.4 g/d, respectively. PFOS concentrations did not show differences between 2006 and 2008. However, PFOA concentrations were higher in 2008/5/26, while comparing other samplings. The ratio of solid:liquid PFPA (2.1:1.0) [(ng/g)/(ng/L)] was lower than PFOA (13.9:1.0) [(ng/g)/(ng/L)] and PFOS (17.6:1.0) [(ng/g)/(ng/L)]. The shorter chain (more hydrophilic) PFC was better to dissolve in water rather than adsorb onto suspended solids. PFOS also showed more potential to attach in the suspended solids than PFOA.

  20. Perfluorinated chemicals: differential toxicity, inhibition of aromatase activity and alteration of cellular lipids in human placental cells.

    PubMed

    Gorrochategui, Eva; Pérez-Albaladejo, Elisabet; Casas, Josefina; Lacorte, Sílvia; Porte, Cinta

    2014-06-01

    The cytotoxicity of eight perfluorinated chemicals (PFCs), namely, perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorododecanoic acid (PFDoA), perfluorobutanesulfonate (PFBS), perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) was assessed in the human placental choriocarcinoma cell line JEG-3. Only the long chain PFCs--PFOS, PFDoA, PFNA, PFOA--showed significant cytotoxicity in JEG-3 cells with EC50 values in the range of 107 to 647 μM. The observed cytotoxicity was to some extent related to a higher uptake of the longer chain PFCs by cells (PFDoA>PFOS≫PFNA>PFOA>PFHxA). Moreover, this work evidences a high potential of PFOS, PFOA and PFBS to act as aromatase inhibitors in placental cells with IC50s in the range of 57-80 μM, the inhibitory effect of PFBS being particularly important despite the rather low uptake of the compound by cells. Finally, exposure of JEG-3 cells to a mixture of the eight PFCs (0.6 μM each) led to a relative increase (up to 3.4-fold) of several lipid classes, including phosphatidylcholines (PCs), plasmalogen PC and lyso plasmalogen PC, which suggests an interference of PFCs with membrane lipids. Overall, this work highlights the ability of the PFC mixture to alter cellular lipid pattern at concentrations well below those that generate toxicity, and the potential of the short chain PFBS, often considered a safe substitute of PFOS, to significantly inhibit aromatase activity in placental cells.

  1. Perfluorinated Compounds and Polybrominated Diphenyl Ethers in Great Blue Heron Eggs from Three Colonies on the Mississippi River, Minnesota

    USGS Publications Warehouse

    Custer, T.W.; Kannan, K.; Tao, L.; Yun, S.-H.; Trowbridge, A.

    2010-01-01

    Archived Great Blue Heron (Ardea herodias) eggs (N = 16) collected in 1993 from three colonies on the Mississippi River in Minnesota were analyzed in 2007 for perfluorinated compounds (PFCs) and polybrominated diphenyl ethers (PBDEs). One of the three colonies, Pig's Eye, was located near a presumed source of PFCs. Based on a multivariate analysis, the pattern of nine PFC concentrations differed significantly between Pig's Eye and the upriver (P = 0.002) and downriver (P = 0.02) colonies; but not between the upriver and downriver colonies (P = 0.25). Mean concentrations of perfluorooctane sulfonate (PFOS), a major PFC compound, were significantly higher at the Pig's Eye colony (geometric mean = 940 ng/g wet weight) than at upriver (60 ng/g wet weight) and downriver (131 ng/g wet weight) colonies. Perfluorooctane sulfonate concentrations from the Pig's Eye colony are among the highest reported in bird eggs. Concentrations of PFOS in Great Blue Heron eggs from Pig's Eye were well below the toxicity thresholds estimated for Bobwhite Quail (Colinus virginianus) and Mallards (Anas platyrhynchos), but within the toxicity threshold estimated for White Leghorn Chickens (Gallus domesticus). The pattern of six PBDE congener concentrations did not differ among the three colonies (P = 0.08). Total PBDE concentrations, however, were significantly greater (P = 0.03) at Pig's Eye (geometric mean = 142 ng/g wet weight) than the upriver colony (13 ng/g wet weight). Polybrominated diphenyl ether concentrations in two of six Great Blue Heron eggs from the Pig's Eye colony were within levels associated with altered reproductive behavior in American Kestrels (Falco sparverius).

  2. Oral (Gavage) Combined Developmental and Perinatal/Postnatal Reproduction Toxicity Study of Ammonium Salt of Perfluorinated Hexanoic Acid in Mice.

    PubMed

    Iwai, Hiroyuki; Hoberman, Alan M

    2014-05-01

    The reproductive toxicity potential of Ammonium Salt of Perfluorinated Hexanoic Acid (PFHxA Ammonium Salt) in pregnant Crl: CD1(ICR) mice was investigated. Twenty females/group were administered the test substance or vehicle once daily from gestation day 6 through 18. Phase 1 doses: 0, 100, 350, and 500 mg/kg/d; phase 2: 0, 7, 35, and 175 mg/kg/d. Parameters evaluated include mortality, viability, body weights, clinical signs, abortions, premature deliveries, pregnancy and fertility, litter observations, maternal behavior, and sexual maturity in the F1 generation. The level of PFHxA Ammonium Salt was measured in the liver of F0 and F1 mice. At doses of 350 and 500 mg/kg/d maternal mortalities, excess salivation and changes in body weight gains occurred. Pup body weights were reduced on postpartum day (PPD) 0 in all the dosage groups, but persisted only in the 350 and 500 mg/kg/d groups. Additional effects at 300 and 500 mg/kg/d included stillbirths, reductions in viability indices, and delays in physical development. Levels of PFHxA Ammonium Salt in the livers of the 100 mg/kg/d dams were all below the lower limit of quantization (0.02 µg/mL); in the 350 mg/kg/d group, 3 of the 8 samples had quantifiable analytical results. In phase 2 no PFHxA Ammonium Salt was found in the liver. Adverse effects occurred only in the 175 mg/kg/d group and consisted of increased stillborn pups, pups dying on PPD 1, and reduced pup weights on PPD 1. Based on these data, the maternal and reproductive no observable adverse effect level of PFHxA Ammonium Salt is 100 mg/kg/d.

  3. The relationship between perfluorinated chemical levels in the feathers and livers of birds from different trophic levels.

    PubMed

    Meyer, Johan; Jaspers, Veerle L B; Eens, Marcel; de Coen, Wim

    2009-11-01

    Although feathers have been used successfully for monitoring heavy metals and organic pollutants, there are currently no data available on the use of feathers as indicators of perfluorinated chemical (PFC) exposure in birds. Also, no study has evaluated PFC levels in birds with different diets from different habitats. In the current study we investigated the PFC exposure of five different bird species from the same geographic region in Belgium, using both feathers and liver tissue. The highest mean liver perfluorooctane sulfonate (PFOS) levels were found in the Grey Heron (476 ng/g ww) followed by the Herring Gull (292 ng/g ww) and Eurasian Sparrowhawk (236 ng/g ww), whereas the Eurasian Magpie (17 ng/g ww) and the Eurasian Collared Dove (12 ng/g ww) had the lowest levels. The PFOS levels in the feathers showed a different pattern. The Grey Heron had the highest feather PFOS levels (247 ng/g dw), the Eurasian Sparrowhawk (102 ng/g dw) had the second highest feather PFOS levels, followed by the Herring Gull (79 ng/g dw) and the Eurasian Collared Dove (48 ng/g dw), and the lowest levels were found in the Eurasian Magpie (31 ng/g dw). Overall, there was a significant positive correlation (Pearson, R=0.622, p<0.01) between the feather and liver PFOS levels, indicating that feathers could be an alternative bioindicator for PFOS exposure in birds. However, caution should be taken as there was no significant correlation between the PFOS levels in the feathers and livers of the individual species. In general, birds from a higher trophic level had higher PFC levels in their tissues. This indicates that diet plays a role in PFC exposure in birds and confirms the bioaccumulation potential of PFC.

  4. Plasma Source Development for Effective Dissociation and Abatement of Perfluorinated Compounds for the Reduction of Gas Emissions

    NASA Astrophysics Data System (ADS)

    Mahoney, Leonard J.

    2001-10-01

    Perfluorinated gas compounds (PFCs) are widely used in the semiconductor industry for etching process and for cleaning of chemical vapor deposition (CVD) systems. However, most of these compounds have very high infrared adsorbance strengths and long life times (i.e. several times greater than carbon dioxide). Thus their emissions can strongly contribute to global warming if left unabated. To reduce PFC emissions, the industry has adopted high power density, sub-atmospheric plasma sources to completely dissociate F-bearing compounds at the point of use or to completely convert PFC emissions within the post process exhaust stream. Many electrodeless plasma sources have been applied including microwave, conventional inductive, and ferrite-based inductive plasma devices. As a general scaling rule, most all of these devices provide effective electric field strengths on the order 1-10 V/cm and power densities of 0.1-10 W/cm3 into electronegative discharges at pressures ranging from 0.1-100 Torr. To explore one contemporary example, we examine the properties a ferrite-based, inductively-coupled plasma source as applied to typical processes used in CVD chamber clean and PFC-based etching processes. Along with the operational properties of this device, we examine mass spectroscopy measurements of residual gases from the source when used to (1) fully dissociate high flows of pure NF3 and mixtures of C3F8/O2 and (2) abate moderate flows of CF4, C2F6 and SF6 in combination with O2 or H2O vapor. Also, we review select plasma engineering topics related to these PFC abatement approaches whose study would greatly advance the performance and cost effectiveness of plasma abatement technology within the industry.

  5. Levels and trends of the emerging contaminants HBCDs (hexabromocyclododecanes) and PFCs (perfluorinated compounds) in marine shellfish along French coasts.

    PubMed

    Munschy, C; Marchand, P; Venisseau, A; Veyrand, B; Zendong, Z

    2013-04-01

    The levels and congener patterns of HBCDs (hexabromocyclododecanes) and PFCs (perfluorinated compounds) were determined in filter-feeding molluscs collected in 2008 and 2010 along the coasts of mainland France. α-HBCD and PFOS (perfluorooctane sulfonate) were detected in all samples, revealing widespread contamination of the coastal environment by these emerging contaminants. The spatial distribution of Σ-HBCD concentrations showed higher median levels in samples from the Mediterranean Sea and English Channel respectively, i.e. 0.19 ng g(-1) wet weight (ww) and 0.08 ng g(-1) ww, related to high anthropogenic pressure from urban and industrial activities, while the median concentration was 0.05 ng g(-1) ww in samples from the Atlantic coast. Among PFCs, PFOS was the only compound detected in all samples and PFDA (perfluorodecanoic acid) was the second most frequently-detected compound. PFOS median concentrations were 0.18 ng g(-1) ww, 0.09 ng g(-1) ww and 0.04 ng g(-1) ww in samples from the English Channel, the Atlantic coast and the Mediterranean coast respectively. The highest PFOS concentration was found in the Loire estuary, possibly related to local industrial activities. The Mediterranean samples showed a different pattern, with predominant long-chain PFCAs (perfluorocarboxylic acids), suggesting the presence of alternative sources on the Mediterranean coast. The temporal trends studied in archived samples from the Seine estuary site showed a significant exponential increase in HBCD concentrations between 1981 and 2011, with a doubling time of 7 years, while PFOS levels underwent a significant linear decrease over time. These trends are coherent with current regulations on the use of these compounds. The results presented in this paper provide the first data on the contamination of the French coastal marine environment by the selected emerging compounds, and constitute a reference for the future monitoring of French coastal contamination by emerging

  6. Nano-Sized Cyclodextrin-Based Molecularly Imprinted Polymer Adsorbents for Perfluorinated Compounds—A Mini-Review

    PubMed Central

    Karoyo, Abdalla H.; Wilson, Lee D.

    2015-01-01

    Recent efforts have been directed towards the design of efficient and contaminant selective remediation technology for the removal of perfluorinated compounds (PFCs) from soils, sediments, and aquatic environments. While there is a general consensus on adsorption-based processes as the most suitable methodology for the removal of PFCs from aquatic environments, challenges exist regarding the optimal materials design of sorbents for selective uptake of PFCs. This article reviews the sorptive uptake of PFCs using cyclodextrin (CD)-based polymer adsorbents with nano- to micron-sized structural attributes. The relationship between synthesis of adsorbent materials and their structure relate to the overall sorption properties. Hence, the adsorptive uptake properties of CD-based molecularly imprinted polymers (CD-MIPs) are reviewed and compared with conventional MIPs. Further comparison is made with non-imprinted polymers (NIPs) that are based on cross-linking of pre-polymer units such as chitosan with epichlorohydrin in the absence of a molecular template. In general, MIPs offer the advantage of selectivity, chemical tunability, high stability and mechanical strength, ease of regeneration, and overall lower cost compared to NIPs. In particular, CD-MIPs offer the added advantage of possessing multiple binding sites with unique physicochemical properties such as tunable surface properties and morphology that may vary considerably. This mini-review provides a rationale for the design of unique polymer adsorbent materials that employ an intrinsic porogen via incorporation of a macrocyclic compound in the polymer framework to afford adsorbent materials with tunable physicochemical properties and unique nanostructure properties. PMID:28347047

  7. Structural and thermal stabilities of layered Li(Ni 1/3Co 1/3Mn 1/3)O 2 materials in 18650 high power batteries

    NASA Astrophysics Data System (ADS)

    He, Yan-Bing; Ning, Feng; Yang, Quan-Hong; Song, Quan-Sheng; Li, Baohua; Su, Fangyuan; Du, Hongda; Tang, Zhi-Yuan; Kang, Feiyu

    The structural and thermal stabilities of the layered Li(Ni 1/3Co 1/3Mn 1/3)O 2 cathode materials under high rate cycling and abusive conditions are investigated using the commercial 18650 Li(Ni 1/3Co 1/3Mn 1/3)O 2/graphite high power batteries. The Li(Ni 1/3Co 1/3Mn 1/3)O 2 materials maintain their layered structure even when the power batteries are subjected to 200 cycles with 10 C discharge rate at temperatures of 25 and 50 °C, whereas their microstructure undergoes obvious distortion, which leads to the relatively poor cycling performance of power batteries at high charge/discharge rates and working temperature. Under abusive conditions, the increase in the battery temperature during overcharge is attributed to both the reactions of electrolyte solvents with overcharged graphite anode and Li(Ni 1/3Co 1/3Mn 1/3)O 2 cathode and the Joule heat that results from the great increase in the total resistance (R cell) of batteries. The reactions of fully charged Li(Ni 1/3Co 1/3Mn 1/3)O 2 cathodes and graphite anodes with electrolyte cannot be activated during short current test in the fully charged batteries. However, these reactions occur at around 140 °C in the fully charged batteries during oven test, which is much lower than the temperature of about 240 °C required for the reactions outside batteries.

  8. D/H Toward BD+28 4211: First FUSE Results

    NASA Technical Reports Server (NTRS)

    Sonneborne, George; Andre, M.; Oliveira, C.; Friedman, S. D.; Howk, J. C.; Kruk, J. W.; Moos, H. W.; Oegerle, W. R.; Sembach, K. R.; Chayer, P.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    The atomic deuterium-to-hydrogen abundance ratio has been evaluated for the sight line toward the hot O subdwarf BD+28(sup circ) 4211. High signal-to-noise ratio (S/N is approx. 100) observations covering the wavelength range 905 to 1187 angstroms at a wavelength resolving power of lambda/Delta/lambda at approx. 20,000 were obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. BD+28(sup circ) 4211 is approx. 00 pc away with a total H I column density of approx. 10(exp 19)/sq cm, much higher than is typically found in the local interstellar medium (ISM). The deuterium column density was measured by analyzing several D I Lyman series transitions (Lyman delta, C, epsilon, eta, theta, iota with curve of growth and profile fitting techniques, after determining which lines were free of interference from other interstellar species and narrow stellar features. The neutral hydrogen column density was measured by an analysis of the Lyman-alpha profile using HST/Space Telescope Imaging Spectrograph (STIS) and Goddard High Resolution Spectrograph (GHRS) spectra. The stellar spectrum of BD+28(sup circ) 4211 was modelled to assist in determining the sensitivity of H I (Ly-alpha) and D I to the continuum placement and to identify stellar transitions. The D I and H I column densities, their uncertainties, and potential sources of systematic error will be presented. This work is based on data obtained for the FUSE Guaranteed Time Team by the NASA-CNES-CSA FUSE mission operated by the Johns Hopkins University. Financial support to U. S. participants has been provided in part by NASA contract NAS5-32985.

  9. Tree classification with fused mobile laser scanning and hyperspectral data.

    PubMed

    Puttonen, Eetu; Jaakkola, Anttoni; Litkey, Paula; Hyyppä, Juha

    2011-01-01

    Mobile Laser Scanning data were collected simultaneously with hyperspectral data using the Finnish Geodetic Institute Sensei system. The data were tested for tree species classification. The test area was an urban garden in the City of Espoo, Finland. Point clouds representing 168 individual tree specimens of 23 tree species were determined manually. The classification of the trees was done using first only the spatial data from point clouds, then with only the spectral data obtained with a spectrometer, and finally with the combined spatial and hyperspectral data from both sensors. Two classification tests were performed: the separation of coniferous and deciduous trees, and the identification of individual tree species. All determined tree specimens were used in distinguishing coniferous and deciduous trees. A subset of 133 trees and 10 tree species was used in the tree species classification. The best classification results for the fused data were 95.8% for the separation of the coniferous and deciduous classes. The best overall tree species classification succeeded with 83.5% accuracy for the best tested fused data feature combination. The respective results for paired structural features derived from the laser point cloud were 90.5% for the separation of the coniferous and deciduous classes and 65.4% for the species classification. Classification accuracies with paired hyperspectral reflectance value data were 90.5% for the separation of coniferous and deciduous classes and 62.4% for different species. The results are among the first of their kind and they show that mobile collected fused data outperformed single-sensor data in both classification tests and by a significant margin.

  10. Bis(1,3-dimethyl-1,3-diazinan-2-one)dinitratodioxidouranium(VI)

    PubMed Central

    Suzuki, Tomoya; Kawasaki, Takeshi; Ikeda, Yasuhisa

    2011-01-01

    The title compound, [U(NO3)2O2(C6H12N2O)2], exhibits a hexa­gonal–bipyramidal geometry around the UVI ion, which is situated on an inversion centre and coordinated by two oxide ligands in the axial positions, and four O atoms from two bidentate NO3 − and two O atoms from two 1,3-dimethyl-1,3-diazinan-2-one (DMPU) ligands in the equatorial plane. These ligands are located in trans positions. The –(CH2)3– moiety in the DMPU ligand is disordered over two positions in a 0.786 (11):0.214 (11) ratio. PMID:21522544

  11. Biodegradation of 1,3,5-trinitro-1,3,5-triazine (RDX).

    PubMed

    Lee, Sheng-Yih; Brodman, Bruce W

    2004-01-01

    Two bacteria were isolated from 1,3,5-trinitro-1,3,5-triazine (RDX) contaminated soil at Picatinny Arsenal, New Jersey. These organisms were subsequently identified as Rhiziobium rhizogenes BL and Burkholderia sp.BL by the Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH (DSMZ, German Collection of Microorganisms and Cell Cultures). In addition a fungus, identified as Cladosporium cladosporioides by DSMZ, was found to be growing on water wet RDX. All of these organisms were found to degrade RDX. The two bacteria were found to represent new species that have not been reported before. It was found that these organisms along with an added carbon source could degrade RDX to simple gaseous products. Data are presented that elucidate the mechanisms of RDX biodegradation for these organisms.

  12. Synthesis of planar chiral ferrocenyl 1,3-diamines and 1,3-amino ethers.

    PubMed

    Anderson, James C; Blake, Alexander J; Arnall-Culliford, Jennifer C

    2003-10-21

    The efficient syntheses of novel planar chiral 1,3-diamines and 1,3-amino ethers with an oxy or amino function directly bound to the cyclopentadienyl ring of ferrocene has been developed. The key reaction is the Cu2O promoted substitution of (pR)-N,N-diisopropyl-2-iodoferrocenecarboxamide with either phthalimide or AcOH to introduce nitrogen or oxygen functionality onto the cyclopentadienyl ring. The enantiomerically pure iodoferrocene derivative is available from the known enantioselective ortho-lithiation of N,N-diisopropylferrocenecarboxamide with n-BuLi-sparteine. In the course of these studies the synthesis of a novel C2 symmetric C-2 dimer of N,N-dimethyl-1-ferrocenylethylamine was characterised by single crystal X-ray diffraction.

  13. Fused Deposition Technique for Continuous Fiber Reinforced Thermoplastic

    NASA Astrophysics Data System (ADS)

    Bettini, Paolo; Alitta, Gianluca; Sala, Giuseppe; Di Landro, Luca

    2016-12-01

    A simple technique for the production of continuous fiber reinforced thermoplastic by fused deposition modeling, which involves a common 3D printer with quite limited modifications, is presented. An adequate setting of processing parameters and deposition path allows to obtain components with well-enhanced mechanical characteristics compared to conventional 3D printed items. The most relevant problems related to the simultaneous feeding of fibers and polymer are discussed. The properties of obtained aramid fiber reinforced polylactic acid (PLA) in terms of impregnation quality and of mechanical response are measured.

  14. Fused Deposition Technique for Continuous Fiber Reinforced Thermoplastic

    NASA Astrophysics Data System (ADS)

    Bettini, Paolo; Alitta, Gianluca; Sala, Giuseppe; Di Landro, Luca

    2017-02-01

    A simple technique for the production of continuous fiber reinforced thermoplastic by fused deposition modeling, which involves a common 3D printer with quite limited modifications, is presented. An adequate setting of processing parameters and deposition path allows to obtain components with well-enhanced mechanical characteristics compared to conventional 3D printed items. The most relevant problems related to the simultaneous feeding of fibers and polymer are discussed. The properties of obtained aramid fiber reinforced polylactic acid (PLA) in terms of impregnation quality and of mechanical response are measured.

  15. Processing of fused silicide coatings for carbon-based materials

    NASA Technical Reports Server (NTRS)

    Smialek, J. L.

    1982-01-01

    The processing and oxidation resistance of fused Al-Si and Ni-Si slurry coatings on ATJ graphite was studied. Ni-Si coatings in the 70 to 90 percent Si range were successfully processed to melt, wet, and bond to the graphite. The molten coatings also infiltrated the porosity in graphite and reacted with it to form SiC in the coating. Cyclic oxidation at 1200 C showed that these coatings were not totally protective because of local attack of the substrate, due to the extreme thinness of the coatings in combination with coating cracks.

  16. Shocks in Dense Clouds in the Vela Supernova Remnant: FUSE

    NASA Technical Reports Server (NTRS)

    Nichols, Joy; Sonneborn, George (Technical Monitor)

    2002-01-01

    We have obtained 8 LWRS FUSE spectra to study a recently identified interaction of the Vela supernova remnant with a dense cloud region along its western edge. The goal is to quantify the temperature, ionization, density, and abundance characteristics associated with this shock/dense cloud interface by means of UV absorption line studies. Our detection of high-velocity absorption line C I at +90 to +130 km/s with IUE toward a narrow region interior to the Vela SNR strongly suggests the Vela supernova remnant is interacting with a dense ISM or molecular cloud. The shock/dense cloud interface is suggested by (1) the rarity of detection of high-velocity C I seen in IUE spectra, (2) its very limited spatial distribution in the remnant, and (3) a marked decrease in X-ray emission in the region immediately west of the position of these stars where one also finds a 100 micron emission ridge in IRAS images. We have investigated the shock physics and general properties of this interaction region through a focussed UV absorption line study using FUSE spectra. We have FUSE data on OVI absorption lines observed toward 8 stars behind the Vela supernova remnant (SNR). We compare the OVI observations with IUE observations of CIV absorption toward the same stars. Most of the stars, which are all B stars, have complex continua making the extraction of absorption lines difficult. Three of the stars, HD 72088, HD 72089 and HD 72350, however, are rapid rotators (v sin i less than 100 km/s) making the derivation of absorption column densities much easier. We have measured OVI and CIV column densities for the "main component" (i.e. the low velocity component) for these stars. In addition, by removing the H2 line at 1032.35A (121.6 km/s relative to OVI), we find high velocity components of OVI at approximately 150 km/s that we attribute to the shock in the Vela SNR. The column density ratios and magnitudes are compared to both steady shock models and results of hydrodynamical SNR

  17. Occurrence and persistence of perfluorooctanesulfonate and other perfluorinated surfactants in groundwater at a fire-training area at Wurtsmith Air Force Base, Michigan, USA.

    PubMed

    Moody, Cheryl A; Hebert, Gretchen N; Strauss, Steven H; Field, Jennifer A

    2003-04-01

    Various formulations of fire-extinguishing materials, including aqueous film-forming foams (AFFFs), were used as part of fire-training exercises conducted at Wurtsmith Air Force Base (WAFB) in northeastern Michigan from the 1950s until the base was decommissioned in 1993. As a result of past fire-training exercises, AFFF-laden wastewater containing fuels, solvents, and other materials directly entered groundwater without prior treatment. Perfluorinated surfactants are key components in some AFFF formulations. In this study, groundwater was analyzed for perfluoroalkanesulfonates and perfluorocarboxylates. Perfluoroalkanesulfonates were directly detected using negative-ion electrospray ionization mass spectrometry. Derivatized perfluorocarboxylates were detected using electron impact gas chromatography-mass spectrometry. Groundwater from wells around fire-training area FTA-02 at WAFB contained four perfluorinated surfactants ranging in concentration from 3 to 120 microg L(-1): perfluorooctanesulfonate (PFOS); perfluorohexanesulfonate; perfluorooctanoate; and perfluorohexanoate. This is the first report demonstrating that PFOS, recently shown to be toxic to organisms ranging from zooplankton to primates, is still present in groundwater in measurable quantities five or more years after its last known use.

  18. Sources and fate of perfluorinated compounds in the aqueous environment and in drinking water of a highly urbanized and industrialized area in Italy.

    PubMed

    Castiglioni, Sara; Valsecchi, Sara; Polesello, Stefano; Rusconi, Marianna; Melis, Manuela; Palmiotto, Marinella; Manenti, Angela; Davoli, Enrico; Zuccato, Ettore

    2015-01-23

    Perfluorinated substances are listed among emerging contaminants because they are globally distributed, environmentally persistent, bioaccumulative and potentially harmful. In a three-year monitoring campaign (2010-2013) we investigated the occurrence, sources and fate of nine perfluoroalkylcarboxylic acids and three perfluoroalkylsulfonic acids, in the most industrialized region of Italy. Composite samples were collected in influents and effluents of wastewater treatment plants (WWTPs), in the main rivers flowing through the basin, and in raw groundwater and finished drinking water. Samples were analyzed by liquid chromatography tandem mass spectrometry. Perfluorinated substances were not removed in WWTPs and those receiving industrial wastes discharged up to 50 times the loads of WWTPs receiving municipal wastes. The mass balance of the emissions in the River Lambro basin showed continuously increasing contamination from north to south and differences in the composition of homologues in the west and east sides of the basin. Ground and drinking water were contaminated in industrial areas, but these substances were removed well in Milan. Contamination from industrial sources was prevalent over urban sources, contributing to 90% of the loads measured at the closure of the basin. The River Lambro was confirmed as one of the main sources of contamination in the Po River.

  19. Ultrafast double-pulse ablation of fused silica

    SciTech Connect

    Chowdhury, Ihtesham H.; Xu Xianfan; Weiner, Andrew M.

    2005-04-11

    Ultrafast pump-probe experiments were used to study high-intensity ultrafast pulse-ablation dynamics in fused silica. Two laser pulses with varied time delay and pulse energy were used to irradiate fused silica samples and observe the transient reflectivity and transmissivity of the probe pulse. It was seen that the probe reflectivity initially increased due to the formation of free-electron plasma and then dropped to a low value within a period of about 10 ps caused by a rapid structural change at the surface. The time-resolved measurements of reflectivity and transmissivity were also related to atomic force microscopy measurements of the depth of the laser-ablated hole. It was seen that the depth peaked at zero delay between the pulses and decreased within a period of about 1 ps as the temporal separation between the pulses was increased caused by the screening by the plasma produced by the first pulse. When the temporal separation is about 100 ps or longer, evidence for melting and resolidification during double-pulse ablation was also observed in the form of ridges at the circumference of the ablated holes.

  20. Exploding metallic foil fuse modeling at Los Alamos

    SciTech Connect

    Lindemuth, I.R.; Reinovsky, R.E.; Goforth, J.H.

    1989-01-01

    A ''first-principles'' computational model of exploding metallic foil behavior has been developed at Los Alamos. The model couples zero-dimensional magnetohydrodynamics with ohmic heating and electrical circuit equations and uses the Los Alamos SESAME atomic data base computer library to determine the foil material's temperature- and density-dependent pressure, specific energy, and electrical conductivity. The model encompasses many previously successful empirical models and offers plausible physical explanations of phenomena not treated by the empirical models. In addition to addressing the electrical circuit performance of an exploding foil, the model provides information on the temporal evolution of the foil material's density, temperature, pressure, electrical conductivity, and expansion and translational velocities. In this paper, we report the physical insight gained by computational studies of two opening switch concepts being developed for application in an FCG-driven 1-MJ-class imploding plasma z-pinch experiment. The first concept considered is a ''conventional'' electrically exploded fuse, which has been demonstrated to operate at 16 MA driven by the 15-MJ-class FCG to be used in the 1 MJ implosion experiment. The second concept considered is a Type 2 explosively formed fuse (EFF), which has been demonstrated to operate at the 8 MA level by a 1-MJ-class FCG.

  1. A New Measure for Analyzing and Fusing Sequences of Objects.

    PubMed

    Goulermas, John Yannis; Kostopoulos, Alexandros; Mu, Tingting

    2016-05-01

    This work is related to the combinatorial data analysis problem of seriation used for data visualization and exploratory analysis. Seriation re-sequences the data, so that more similar samples or objects appear closer together, whereas dissimilar ones are further apart. Despite the large number of current algorithms to realize such re-sequencing, there has not been a systematic way for analyzing the resulting sequences, comparing them, or fusing them to obtain a single unifying one. We propose a new positional proximity measure that evaluates the similarity of two arbitrary sequences based on their agreement on pairwise positional information of the sequenced objects. Furthermore, we present various statistical properties of this measure as well as its normalized version modeled as an instance of the generalized correlation coefficient. Based on this measure, we define a new procedure for consensus seriation that fuses multiple arbitrary sequences based on a quadratic assignment problem formulation and an efficient way of approximating its solution. We also derive theoretical links with other permutation distance functions and present their associated combinatorial optimization forms for consensus tasks. The utility of the proposed contributions is demonstrated through the comparison and fusion of multiple seriation algorithms we have implemented, using many real-world datasets from different application domains.

  2. Laser induced damage and fracture in fused silica vacuum windows

    SciTech Connect

    Campbell, J.H.; Hurst, P.A.; Heggins, D.D.; Steele, W.A.; Bumpas, S.E.

    1996-11-01

    Laser-induced damage, that initiates catastrophic fracture, has been observed in large ({le}61 cm dia) fused silica lenses that also serve as vacuum barriers in Nova and Beamlet lasers. If the elastic stored energy in the lens is high enough, the lens will fracture into many pieces (implosion). Three parameters control the degree of fracture in the vacuum barrier window: elastic stored energy (tensile stress), ratio of window thickness to flaw depth, and secondary crack propagation. Fracture experiments were conducted on 15-cm dia fused silica windows that contain surface flaws caused by laser damage. Results, combined with window failure data on Beamlet and Nova, were used to develop design criteria for a ``fail-safe`` lens (that may catastrophically fracture but not implode). Specifically, the window must be made thick enough so that the peak tensile stress is less than 500 psi (3.4 MPa) and the thickness/critical flaw size is less than 6. The air leak through the window fracture and into the vacuum must be rapid enough to reduce the load on the window before secondary crack growth occurs. Finite element stress calculations of a window before and immediately following fracture into two pieces show that the elastic stored energy is redistributed if the fragments ``lock`` in place and thereby bridge the opening. In such cases, the peak stresses at the flaw site can increase, leading to further (i.e. secondary) crack growth.

  3. Covert photo classification by fusing image features and visual attributes.

    PubMed

    Lang, Haitao; Ling, Haibin

    2015-10-01

    In this paper, we study a novel problem of classifying covert photos, whose acquisition processes are intentionally concealed from the subjects being photographed. Covert photos are often privacy invasive and, if distributed over Internet, can cause serious consequences. Automatic identification of such photos, therefore, serves as an important initial step toward further privacy protection operations. The problem is, however, very challenging due to the large semantic similarity between covert and noncovert photos, the enormous diversity in the photographing process and environment of cover photos, and the difficulty to collect an effective data set for the study. Attacking these challenges, we make three consecutive contributions. First, we collect a large data set containing 2500 covert photos, each of them is verified rigorously and carefully. Second, we conduct a user study on how humans distinguish covert photos from noncovert ones. The user study not only provides an important evaluation baseline, but also suggests fusing heterogeneous information for an automatic solution. Our third contribution is a covert photo classification algorithm that fuses various image features and visual attributes in the multiple kernel learning framework. We evaluate the proposed approach on the collected data set in comparison with other modern image classifiers. The results show that our approach achieves an average classification rate (1-EER) of 0.8940, which significantly outperforms other competitors as well as human's performance.

  4. Ball driven type MEMS SAD for artillery fuse

    NASA Astrophysics Data System (ADS)

    Seok, Jin Oh; Jeong, Ji-hun; Eom, Junseong; Lee, Seung S.; Lee, Chun Jae; Ryu, Sung Moon; Oh, Jong Soo

    2017-01-01

    The SAD (safety and arming device) is an indispensable fuse component that ensures safe and reliable performance during the use of ammunition. Because the application of electronic devices for smart munitions is increasing, miniaturization of the SAD has become one of the key issues for next-generation artillery fuses. Based on MEMS technology, various types of miniaturized SADs have been proposed and fabricated. However, none of them have been reported to have been used in actual munitions due to their lack of high impact endurance and complicated explosive train arrangements. In this research, a new MEMS SAD using a ball driven mechanism, is successfully demonstrated based on a UV LIGA (lithography, electroplating and molding) process. Unlike other MEMS SADs, both high impact endurance and simple structure were achieved by using a ball driven mechanism. The simple structural design also simplified the fabrication process and increased the processing yield. The ball driven type MEMS SAD performed successfully under the desired safe and arming conditions of a spin test and showed fine agreement with the FEM simulation result, conducted prior to its fabrication. A field test was also performed with a grenade launcher to evaluate the SAD performance in the firing environment. All 30 of the grenade samples equipped with the proposed MEMS SAD operated successfully under the high-G setback condition.

  5. Planning the FUSE Mission Using the SOVA Algorithm

    NASA Technical Reports Server (NTRS)

    Lanzi, James; Heatwole, Scott; Ward, Philip R.; Civeit, Thomas; Calvani, Humberto; Kruk, Jeffrey W.; Suchkov, Anatoly

    2011-01-01

    Three documents discuss the Sustainable Objective Valuation and Attainability (SOVA) algorithm and software as used to plan tasks (principally, scientific observations and associated maneuvers) for the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. SOVA is a means of managing risk in a complex system, based on a concept of computing the expected return value of a candidate ordered set of tasks as a product of pre-assigned task values and assessments of attainability made against qualitatively defined strategic objectives. For the FUSE mission, SOVA autonomously assembles a week-long schedule of target observations and associated maneuvers so as to maximize the expected scientific return value while keeping the satellite stable, managing the angular momentum of spacecraft attitude- control reaction wheels, and striving for other strategic objectives. A six-degree-of-freedom model of the spacecraft is used in simulating the tasks, and the attainability of a task is calculated at each step by use of strategic objectives as defined by use of fuzzy inference systems. SOVA utilizes a variant of a graph-search algorithm known as the A* search algorithm to assemble the tasks into a week-long target schedule, using the expected scientific return value to guide the search.

  6. Sc(OTf)3-catalyzed three-component cyclization of arylamines, β,γ-unsaturated α-ketoesters, and 1,3-dicarbonyl compounds for the synthesis of highly substituted 1,4-dihydropyridines and tetrahydropyridines.

    PubMed

    Liu, Lu; Sarkisian, Ryan; Deng, Yongming; Wang, Hong

    2013-06-07

    A Sc(OTf)3-catalyzed three-component cyclization reaction of arylamines, β,γ-unsaturated α-ketoesters and 1,3-dicarbonyl compounds was developed to synthesize highly substituted 1,4-dihydropyridines and fused bicyclic tetrahydropyridines carrying a quaternary all-carbon center.

  7. Preparation, characterization of LiNi{sub 1/3}Mn{sub 1/3}Co{sub 1/3}O{sub 2} film cathode.

    SciTech Connect

    Kang, S. H.; Abraham, D. P.; Chemical Engineering

    2006-01-01

    Positive electrodes based on the LiNi{sub 1/3}Mn{sub 1/3}Co{sub 1/3}O{sub 2} material are being evaluated in high-power lithium-ion cells for hybrid-electric vehicle applications. To determine performance degradation mechanisms that are associated with the active material, we prepared carbon- and binder-free LiNi{sub 1/3}Mn{sub 1/3}Co{sub 1/3}O{sub 2} film cathode on a Pt substrate using a sol-gel spin coating technique. The material was characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Initial data from cyclic voltammetry, galvanostatic cycling, and electrochemical impedance spectroscopy measurements conducted on the electrodes are reported.

  8. Electrochemical characteristics of layered LiNi 1/3Co 1/3Mn 1/3O 2 and with different synthesis conditions

    NASA Astrophysics Data System (ADS)

    He, Ping; Wang, Haoran; Qi, Lu; Osaka, Tetsuya

    LiNi 1/3Mn 1/3Co 1/3O 2 had been successfully prepared from spherical composite carbonate via a simple uniform-phase precipitation method [P. He, H. Wang, L. Qi, T. Osaka, J. Power Sources, in press] at normal pressure, using nickel, cobalt and manganese sulfate and ammonia bicarbonate as reactants. The preparation of spherical composite carbonate was significantly dependant on synthetic condition, such as the reaction temperature, feed rate, molar ratio of these reactants, etc. The optimized condition resulted in spherical composite carbonate of which the particle size distribution was uniform, as observed by scanning electronic microscopy (SEM). Calcination of the uniform composite carbonate with lithium carbonate at high temperature led to a well-ordered layer structured LiNi 1/3Mn 1/3Co 1/3O 2 as confirmed by X-ray diffraction (XRD), without obvious change in shape. Due to the homogeneity of the composite carbonate, the final product, LiNi 1/3Mn 1/3Co 1/3O 2, was also significantly uniform, i.e., the average particle size was of about 10 μm in diameter and the distribution was relatively narrow. As a result, the corresponding tap density was also high, approximately 2.32 g cm -3, of which the value is very near to that of commercialized LiCoO 2. In the voltage range of 2.8-4.2, 2.8-4.35 and 2.8-4.5 V, the discharge capacities of LiNi 1/3Mn 1/3Co 1/3O 2 electrode were 159, 168 and 179 mAh g -1, respectively, with good cyclability.

  9. Seismic design or retrofit of buildings with metallic structural fuses by the damage-reduction spectrum

    NASA Astrophysics Data System (ADS)

    Li, Gang; Jiang, Yi; Zhang, Shuchuan; Zeng, Yan; Li, Qiang

    2015-03-01

    Recently, the structural fuse has become an important issue in the field of earthquake engineering. Due to the trilinearity of the pushover curve of buildings with metallic structural fuses, the mechanism of the structural fuse is investigated through the ductility equation of a single-degree-of-freedom system, and the corresponding damage-reduction spectrum is proposed to design and retrofit buildings. Furthermore, the controlling parameters, the stiffness ratio between the main frame and structural fuse and the ductility factor of the main frame, are parametrically studied, and it is shown that the structural fuse concept can be achieved by specific combinations of the controlling parameters based on the proposed damage-reduction spectrum. Finally, a design example and a retrofit example, variations of real engineering projects after the 2008 Wenchuan earthquake, are provided to demonstrate the effectiveness of the proposed design procedures using buckling restrained braces as the structural fuses.

  10. Water quality criteria for hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX).

    PubMed

    Etnier, E L

    1989-04-01

    The occurrence of the munitions compound hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in groundwater surrounding Army ammunition plants may result in contamination of local drinking water supplies. RDX exerts its primary toxic effect in humans on the central nervous system, but also involves gastrointestinal and renal effects. Symptomatic effects following acute exposure include hyperirritability, nausea, vomiting, generalized epileptiform seizures, and prolonged postictal confusion and amnesia. Health effects data were analyzed for RDX, and although no controlled human studies exist concerning the acute or chronic toxic effects of exposure to RDX, sufficient animal toxicity data are available to derive an ambient water quality criterion for the protection of human health. This paper summarizes the available literature on metabolism of RDX and human and animal toxicity. Based on noncarcinogenic mammalian toxicity data, and following the methodologies of the U.S. Environmental Protection Agency, an ambient water quality criterion for the protection of human health of 103 micrograms/liter is proposed for ingestion of drinking water and aquatic foodstuffs. A criterion of 105 micrograms/liter is proposed for ingestion of drinking water alone.

  11. Water quality criteria for hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)

    SciTech Connect

    Etnier, E.L.

    1989-04-01

    The occurrence of the munitions compound hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in groundwater surrounding Army ammunition plants may result in contamination of local drinking water supplies. RDX exerts its primary toxic effect in humans on the central nervous system, but also involves gastrointestinal and renal effects. Symptomatic effects following acute exposure include hyperirritability, nausea, vomiting, generalized epileptiform seizures, and prolonged postictal confusion and amnesia. Health effects data were analyzed for RDX, and although no controlled human studies exist concerning the acute or chronic toxic effects of exposure to RDX, sufficient animal toxicity data are available to derive an ambient water quality criterion for the protection of human health. This paper summarizes the available literature on metabolism of RDX and human and animal toxicity. Based on noncarcinogenic mammalian toxicity data, and following the methodologies of the U.S. Environmental Protection Agency, an ambient water quality criterion for the protection of human health of 103 micrograms/liter is proposed for ingestion of drinking water and aquatic foodstuffs. A criterion of 105 micrograms/liter is proposed for ingestion of drinking water alone.54 references.

  12. Temporal trends (1992-2007) of perfluorinated chemicals in Northern Sea Otters (Enhydra lutris kenyoni) from South-Central Alaska.

    PubMed

    Hart, Kimberly; Gill, Verena A; Kannan, Kurunthachalam

    2009-04-01

    Perfluorinated chemicals (PFCs) have been detected in abiotic and biotic matrices worldwide, including the Arctic Ocean. Considering these chemicals' persistent and bioaccumulative potentials, it was expected that levels of PFCs, like those of many legacy organic pollutants, would respond slowly to the restrictions in production and usage. Temporal trend studies in remote areas, such as the Arctic, can help determine the chronology of contamination and the response of the environment to regulations on PFCs. Prior to this study, temporal trends of PFCs in Alaskan coastal waters had not been examined. In the present study, concentrations of six PFCs were determined in livers of northern sea otters (Enhydra lutris kenyoni) collected from three areas in south-central Alaska (Prince William Sound, n = 36; Resurrection Bay, n = 7; Kachemak Bay, n = 34) from 1992 to 2007. Additionally, previously published profiles and concentrations of PFCs in southern sea otters from California and Asian sea otters from Kamchatka (Russia) were compared to our new data, to determine the geographical differences in PFC profiles among these three regions in the Pacific Ocean. Perfluorooctanesulfonate (PFOS), perfluorooctanesulfonamide (PFOSA), and perfluorononanoate (PFNA) were the predominant PFCs found in the livers of northern sea otters from 1992 to 2007. Other PFCs, such as perfluorooctanoate (PFOA), perfluoroundecanoate (PFUnDA), and perfluorodecanoate (PFDA), were detected less frequently, and at low concentrations. Overall, from 2001 to 2007, a decrease in concentrations of PFOS was found in northern sea otters, suggesting an immediate response to the phase-out in 2000 of perfluorooctanesulfonyl-based compounds by a major producer in the United States. In contrast, concentrations of PFNA in northern sea otters increased by 10-fold from 2004 to 2007. These results indicate that the contribution by PFNA to SigmaPFC concentrations is increasing in northern sea otters. The profiles (i

  13. Optimized condition for etching fused-silica phase gratings with inductively coupled plasma technology.

    PubMed

    Wang, Shunquan; Zhou, Changhe; Ru, Huayi; Zhang, Yanyan

    2005-07-20

    Polymer deposition is a serious problem associated with the etching of fused silica by use of inductively coupled plasma (ICP) technology, and it usually prevents further etching. We report an optimized etching condition under which no polymer deposition will occur for etching fused silica with ICP technology. Under the optimized etching condition, surfaces of the fabricated fused silica gratings are smooth and clean. Etch rate of fused silica is relatively high, and it demonstrates a linear relation between etched depth and working time. Results of the diffraction of gratings fabricated under the optimized etching condition match theoretical results well.

  14. The canister around the FUSE satellite is removed on the pad at CCAS.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At Launch Pad 17A, Cape Canaveral Air Station (CCAS), workers remove another section of the canister surrounding NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. FUSE is designed to scour the cosmos for the fossil record of the origins of the universe hydrogen and deuterium. Scientists will use FUSE to study hydrogen and deuterium to unlock the secrets of how the primordial chemical elements of which all stars, planets and life evolved, were created and distributed since the birth of the universe. FUSE is scheduled to be launched from CCAS June 23 aboard a Boeing Delta II rocket.

  15. The canister around the FUSE satellite is removed on the pad at CCAS.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At Launch Pad 17A, Cape Canaveral Air Station (CCAS), workers look over NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite after sections of the canister have been removed. FUSE is scheduled to be launched from CCAS June 23 aboard a Boeing Delta II rocket. FUSE is designed to scour the cosmos for the fossil record of the origins of the universe hydrogen and deuterium. Scientists will use FUSE to study hydrogen and deuterium to unlock the secrets of how the primordial chemical elements of which all stars, planets and life evolved, were created and distributed since the birth of the universe.

  16. The canister around the FUSE satellite is removed on the pad at CCAS.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At Launch Pad 17A, Cape Canaveral Air Station (CCAS), workers begin to remove the canister around the top of the NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. FUSE is designed to scour the cosmos for the fossil record of the origins of the universe hydrogen and deuterium. Scientists will use FUSE to study hydrogen and deuterium to unlock the secrets of how the primordial chemical elements of which all stars, planets and life evolved, were created and distributed since the birth of the universe. FUSE is scheduled to be launched from CCAS June 23 aboard a Boeing Delta II rocket.

  17. The canister around the FUSE satellite is removed on the pad at CCAS.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At Launch Pad 17A, Cape Canaveral Air Station (CCAS), workers begin removing the lower sections of the canister surrounding NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. FUSE is designed to scour the cosmos for the fossil record of the origins of the universe hydrogen and deuterium. Scientists will use FUSE to study hydrogen and deuterium to unlock the secrets of how the primordial chemical elements of which all stars, planets and life evolved, were created and distributed since the birth of the universe. FUSE is scheduled to be launched from CCAS June 23 aboard a Boeing Delta II rocket.

  18. The canister around the FUSE satellite is removed on the pad at CCAS.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At Launch Pad 17A, Cape Canaveral Air Station (CCAS), workers oversee the removal of the canister from the top of NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. FUSE is designed to scour the cosmos for the fossil record of the origins of the universe hydrogen and deuterium. Scientists will use FUSE to study hydrogen and deuterium to unlock the secrets of how the primordial chemical elements of which all stars, planets and life evolved, were created and distributed since the birth of the universe. FUSE is scheduled to be launched from CCAS June 23 aboard a Boeing Delta II rocket.

  19. Development of Fuses for Protection of Geiger-Mode Avalanche Photodiode Arrays

    NASA Astrophysics Data System (ADS)

    Grzesik, Michael; Bailey, Robert; Mahan, Joe; Ampe, Jim

    2015-11-01

    Current-limiting fuses composed of Ti/Al/Ni were developed for use in Geiger-mode avalanche photodiode arrays for each individual pixel in the array. The fuses were designed to burn out at ˜4.5 × 10-3 A and maintain post-burnout leakage currents less than 10-7 A at 70 V sustained for several minutes. Experimental fuse data are presented and successful incorporation of the fuses into a 256 × 64 pixel InP-based Geiger-mode avalanche photodiode array is reported.

  20. 21 CFR 172.712 - 1,3-Butylene glycol.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Other Specific Usage Additives § 172.712 1,3-Butylene glycol. The food additive 1,3-butylene glycol (CAS... 20740, or may be examined at the Center for Food Safety and Applied Nutrition's Library, Food and...

  1. Transgenic barley expressing a protein-engineered, thermostable (1,3-1,4)-beta-glucanase during germination.

    PubMed Central

    Jensen, L G; Olsen, O; Kops, O; Wolf, N; Thomsen, K K; von Wettstein, D

    1996-01-01

    The codon usage of a hybrid bacterial gene encoding a thermostable (1,3-1,4)-beta-glucanase was modified to match that of the barley (1,3-1,4)-beta-glucanase isoenzyme EII gene. Both the modified and unmodified bacterial genes were fused to a DNA segment encoding the barley high-pI alpha-amylase signal peptide downstream of the barley (1,3-1,4)-beta-glucanase isoenzyme EII gene promoter. When introduced into barley aleurone protoplasts, the bacterial gene with adapted codon usage directed synthesis of heat stable (1,3-1,4)-beta-glucanase, whereas activity of the heterologous enzyme was not detectable when protoplasts were transfected with the unmodified gene. In a different expression plasmid, the codon modified bacterial gene was cloned downstream of the barley high-pI alpha-amylase gene promoter and signal peptide coding region. This expression cassette was introduced into immature barley embryos together with plasmids carrying the bar and the uidA genes. Green, fertile plants were regenerated and approximately 75% of grains harvested from primary transformants synthesized thermostable (1,3-1,4)-beta-glucanase during germination. All three trans genes were detected in 17 progenies from a homozygous T1 plant. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8622963

  2. Prototyping of radially oriented piezoelectric ceramic-polymer tube composites using fused deposition and lost mold processing techniques

    NASA Astrophysics Data System (ADS)

    McNulty, Thomas Francis

    Piezoelectric tube composite hydrophones of 3-1, 3-2, and 2-2 connectivity were developed using Fused Deposition (FD) and lost mold processing (LMP). In this work, a new series of thermoplastic binder formulations, named the ECG series, were developed for the FD process. The ECG-9 formulation exhibits mechanical, thermal, and rheological properties suitable for the Fused Deposition of functional lead zirconate titanate ceramic devices. This binder consists of 100 parts (by weight) Vestoplast 408, 20 parts Escorez 2520, 15 parts Vestowax A-227, and 5 parts Indopol H-1500. Oleic acid, oleyl alcohol, stearic acid, and stearyl alcohol (in toluene) were tested for use as a dispersant in the PZT/ECG-9 system. It was found that stearic acid adsorbs the most onto PZT powder, adsorbing 8.1 mg/m2. Using stearic acid, solutions of increasing concentration (5.0--50.0 g/l) were measured for adsorption. It was found that 30.0 g/l is the minimum concentration necessary for optimum surface coverage. The surfactant-coated powder was compounded with ECG-9 binder to create a 54 vol.% mix. The mix was extruded using a single screw extrusion apparatus into continuous lengths (>30 m) of 1.78 mm diameter filament. Fused Deposition was used to create composite designs of 3-1, 3-2, and 2-2 connectivity. After sintering, samples exhibit a sintered density greater than 97%. Sanders Prototyping (SPI) was used to manufacture molds for use with LMP techniques. Molds of 3-1, 3-2, and 2-2 connectivity were developed. The molds were infiltrated with a 55 vol.% aqueous based PZT slurry. The parts were subjected to a binder decomposition cycle, followed by sintering. Resultant samples were highly variable due to random macro-pores present in the samples after sintering. The resultant preforms were embedded in epoxy, and polished to dimensions of 8.0 mm inside diameter (ID), 14.0 mm outside diameter (OD), and 10.0 mm length (l) the OD and l dimensions are accurate to +/--2%, while the ID is accurate

  3. 21 CFR 573.225 - 1,3-Butylene glycol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.225 1,3-Butylene glycol. The food additive 1,3-butylene glycol (1,3-butanediol) may... 21 Food and Drugs 6 2014-04-01 2014-04-01 false 1,3-Butylene glycol. 573.225 Section 573.225...

  4. 21 CFR 573.225 - 1,3-Butylene glycol.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.225 1,3-Butylene glycol. The food additive 1,3-butylene glycol (1,3-butanediol) may... 21 Food and Drugs 6 2012-04-01 2012-04-01 false 1,3-Butylene glycol. 573.225 Section 573.225...

  5. 21 CFR 573.225 - 1,3-Butylene glycol.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.225 1,3-Butylene glycol. The food additive 1,3-butylene glycol (1,3-butanediol) may... 21 Food and Drugs 6 2013-04-01 2013-04-01 false 1,3-Butylene glycol. 573.225 Section 573.225...

  6. 1,3,2-Dioxaarsolanes. Attempts to synthesize hydrospiroarsoranes

    SciTech Connect

    Gamayurova, V.S.; Niyazov, N.A.

    1986-04-20

    2-Hydroxyalkoxyloxy-1,3,2-dioxaarsolanes were obtained by the interaction of trialkyl arsenites with diols and in the absence of steric hindrance were inclined toward dimerization with the formation of 2,2-ethylenedioxybis(1,3,2-dioxaarsolanes). o-Hydroxyphenylenoxy-benzo-1,3,2-dioxaarsole in solution is in equilibrium with 2-hydro-2,2-spirodibenzo-1,3,2-di-oxaarsoranide.

  7. Separation of 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane and 1,3,5-trinitro-1,3,5- triazacyclohexane by molecularly imprinted solid-phase extraction.

    PubMed

    Wang, Jian; Meng, Zi-Hui; Xue, Min; Qiu, Li-Li; Zhang, Chen-Fan

    2017-03-01

    Synthesis of 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane and 1,3,5-trinitro-1,3,5-triazacyclohexane by the Bachmann process leads to a mixture of both. The separation of 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane and 1,3,5-trinitro-1,3,5-triazacyclohexane from their mixture is difficult because the sizes and physical properties of these homologous compounds are similar. For this purpose, seven molecularly imprinted polymers have been synthesized for each explosive, and a selective solid-phase extraction procedure has been developed. A molecularly imprinted polymer, synthesized with 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane as the template, methacrylic acid as the monomer and trimethylolpropane trimethacrylate as the cross-linking agent in a molar ratio of 1:8:8 showed the best separation capability. A packed cartridge containing this polymer can be reused for 23 solid-phase extraction cycles without repacking, and the total separation capability toward 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane reached 6.81 mg per gram of polymer. 1,3,5-Trinitro-1,3,5-triazacyclohexane was not detected in the separated 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane by high-performance liquid chromatography and vice versa. This newly developed method had the advantages of high recovery (100%) and purity, environmental friendliness, and room temperature operability. This study showed that some molecularly imprinted polymers that cannot absorb target analytes well in the solvent in which the polymers were polymerized might have high-binding capacity for the analytes and show imprinting effects in other solvents.

  8. Characterization of the polishing induced contamination of fused silica optics

    NASA Astrophysics Data System (ADS)

    Pfiffer, Mathilde; Longuet, Jean-Louis; Labrugère, Christine; Fargin, Evelyne; Bousquet, Bruno; Dussauze, Marc; Lambert, Sébastien; Cormont, Philippe; Néauport, Jérôme

    2016-12-01

    Secondary Ion Mass Spectroscopy (SIMS), Electron Probe Micro Analysis (EPMA) and X-Ray Photoelectron Spectroscopy (XPS) were used to analyze the polishing induced contamination layer at the fused silica optics surface. Samples were prepared using an MRF polishing machine and cerium-based slurry. The cerium and iron penetration and concentration were measured in the surface out of defects. Cerium is embedded at the surface in a 60 nm layer and concentrated at 1200 ppmw in this layer while iron concentration falls down at 30 nm. Spatial distribution and homogeneity of the pollution were also studied in scratches and bevel using SIMS and EPMA techniques. An overconcentration was observed in the chamfer and we saw evidence that surface defects such as scratches are specific places that hold the pollutants. A wet etching was able to completely remove the contamination in the scratch.

  9. Fabrication of microchannels in fused silica using femtosecond Bessel beams

    SciTech Connect

    Yashunin, D. A.; Malkov, Yu. A.; Mochalov, L. A.; Stepanov, A. N.

    2015-09-07

    Extended birefringent waveguiding microchannels up to 15 mm long were created inside fused silica by single-pulse irradiation with femtosecond Bessel beams. The birefringent refractive index change of 2–4 × 10{sup −4} is attributed to residual mechanical stress. The microchannels were chemically etched in KOH solution to produce 15 mm long microcapillaries with smooth walls and a high aspect ratio of 1:250. Bessel beams provide higher speed of material processing compared to conventional multipulse femtosecond laser micromachining techniques and permit simple control of the optical axis direction of the birefringent waveguides, which is important for practical applications [Corrielli et al., “Rotated waveplates in integrated waveguide optics,” Nat. Commun. 5, 4249 (2014)].

  10. Fused Nonacyclic Electron Acceptors for Efficient Polymer Solar Cells.

    PubMed

    Dai, Shuixing; Zhao, Fuwen; Zhang, Qianqian; Lau, Tsz-Ki; Li, Tengfei; Liu, Kuan; Ling, Qidan; Wang, Chunru; Lu, Xinhui; You, Wei; Zhan, Xiaowei

    2017-01-25

    We design and synthesize four fused-ring electron acceptors based on 6,6,12,12-tetrakis(4-hexylphenyl)-indacenobis(dithieno[3,2-b;2',3'-d]thiophene) as the electron-rich unit and 1,1-dicyanomethylene-3-indanones with 0-2 fluorine substituents as the electron-deficient units. These four molecules exhibit broad (550-850 nm) and strong absorption with high extinction coefficients of (2.1-2.5) × 10(5) M(-1) cm(-1). Fluorine substitution downshifts the LUMO energy level, red-shifts the absorption spectrum, and enhances electron mobility. The polymer solar cells based on the fluorinated electron acceptors exhibit power conversion efficiencies as high as 11.5%, much higher than that of their nonfluorinated counterpart (7.7%). We investigate the effects of the fluorine atom number and position on electronic properties, charge transport, film morphology, and photovoltaic properties.

  11. Nanoimprint Lithography on curved surfaces prepared by fused deposition modelling

    NASA Astrophysics Data System (ADS)

    Köpplmayr, Thomas; Häusler, Lukas; Bergmair, Iris; Mühlberger, Michael

    2015-06-01

    Fused deposition modelling (FDM) is an additive manufacturing technology commonly used for modelling, prototyping and production applications. The achievable surface roughness is one of its most limiting aspects. It is however of great interest to create well-defined (nanosized) patterns on the surface for functional applications such as optical effects, electronics or bio-medical devices. We used UV-curable polymers of different viscosities and flexible stamps made of poly(dimethylsiloxane) (PDMS) to perform Nanoimprint Lithography (NIL) on FDM-printed curved parts. Substrates with different roughness and curvature were prepared using a commercially available 3D printer. The nanoimprint results were characterized by optical light microscopy, profilometry and atomic force microscopy (AFM). Our experiments show promising results in creating well-defined microstructures on the 3D-printed parts.

  12. The mechanism of growth of quartz crystals into fused silica

    NASA Technical Reports Server (NTRS)

    Fratello, V. J.; Hays, J. F.; Spaepen, F.; Turnbull, D.

    1980-01-01

    It is proposed that the growth of quartz crystals into fused silica is effected by a mechanism involving the breaking of an Si-O bond and its association with an OH group, followed by cooperative motion of the nonbridging oxygen and the hydroxyl group which results in the crystallization of a row of several molecules along a crystalline-amorphous interfacial ledge. This mechanism explains, at least qualitatively, all the results of the earlier experimental study of the dependence of quartz crystal growth upon applied pressure: large negative activation volume; single activation enthalpy below Si-O bond energy; growth velocity constant in time, proportional to the hydroxyl and chlorine content, decreasing with increasing degree of reduction, and enhanced by nonhydrostatic stresses; lower pre-exponential for the synthetic than for the natural silica.

  13. Optical design of Lyman/FUSE. [Far UV Spectroscopic Explorer

    NASA Technical Reports Server (NTRS)

    Content, D. A.; Davila, P. M.; Osantowski, J. F.; Saha, T. T.; Wilson, M. E.

    1990-01-01

    The optical system for the proposed Lyman/Far UV Spectroscopic Explorer (FUSE) orbiting observatory is described and illustrated with drawings and graphs of predicted performance. The system comprises (1) an FUV channel based on a 1.84-m-diameter Rowland circle spectrograph with five high-density modified ellipsiodal near-normal-incidence gratings and an array of four MAMA detectors; (2) an EUV channel with ellipsoidal mirror, planar varied-line-space grating, microchannel-plate array, and wedge-and-strip anode detector; (3) a 70-cm Wolter II glancing-incidence telescope; and (4) a CCD-detector fine-error sensor to provide accurate pointing (within 200 marcsec rms). The resolving powers of the spectrographs are 30,000 in the FUV and 300-600 (wavelength-dependent) in the EUV.

  14. Optical Properties of the DIRC Fused Silica Radiator

    SciTech Connect

    Convery, Mark R

    2003-04-15

    The DIRC detector is successfully operating as the hadronic particle identification system for the BaBar experiment at SLAC. The production of its Cherenkov radiator required much effort in practice, both in manufacture and conception, which in turn required a large number of R&D measurements. One of the major outcomes of this R&D work was an understanding of methods to select radiation hard and optically uniform fused silica material. Others included measurement of the wavelength dependency of the internal reflection coefficient, and its sensitivity to the surface pollution, selection of the radiator support, selection of good optical glue, etc. This note summarizes the optical R&D test results.

  15. Discharging fused silica optics occluded by an electrostatic drive

    NASA Astrophysics Data System (ADS)

    Ugolini, D.; Fitzgerald, C.; Rothbarth, I.; Wang, J.

    2014-03-01

    Charge accumulation on test masses is a potentially limiting noise source for gravitational-wave interferometers, and may occur due to exposure to an electrostatic drive (ESD) in modern test mass suspensions. We verify that an ESD can cause charge accumulation on a fused silica test mass at a rate of 8 × 10-16 C/cm2/h. We also demonstrate a charge mitigation system consisting of a stream of nitrogen ionized by copper feedthrough pins at 3750 VAC. We demonstrate that the system can neutralize positive and negative charge from 10-11 C/cm2 to 3 × 10-14 C/cm2 in under 2 h.

  16. Interferometric Measurement of the Diameters of Fused Quartz Spheres

    NASA Astrophysics Data System (ADS)

    Seino, Shoichi

    1981-12-01

    This paper describes a method for the interferometric measurement of the diameter of a fused quartz sphere with Fabry-Perot etalon. Interference fringes are produced by laser radiation reflected from each surface of the etalon and the adjacent surface of the sphere and then their gaps are measured. The diameter of the sphere is derived by subtracting the two gaps from the plate separation of the etalon. Several lines from a free-running He-Se laser are used as the light sources for the exact fraction method together with the 633 nm line of a Lamb-dip stabilized He-Ne laser. The effects of fringe distortion, caused by laser radiation reflected from the other surface of the transparent sphere, are eliminated by placing a small circular stop at the image point of the light source. Experiments have shown that the precision of measurement of the diameter is about ± 0.16 ppm at 95% confidence interval.

  17. Biased attention and the fused dichotic words test.

    PubMed

    Asbjornsen, A E; Bryden, M P

    1996-05-01

    This study examines the effect of biased attention on the fused dichotic words test (FDWT) and the CV syllables dichotic listening test (CVT). Eight males and eight females were given both tests with two different instructions: to direct attention to the left ear (DL), or to the right ear (DR). These instructions led to highly significant differences in response on the CVT, but only a marginal shift in performance on the FDWT. While the FDWT is not completely unaffected by attentional manipulations, it is far less influenced by such effects than the CVT. This indicates that subject-initiated shifts of attention are much less likely to affect performance on the FDWT than on other dichotic tests and makes it a more valuable task to assess cerebral speech lateralization.

  18. Fusing Quantitative Requirements Analysis with Model-based Systems Engineering

    NASA Technical Reports Server (NTRS)

    Cornford, Steven L.; Feather, Martin S.; Heron, Vance A.; Jenkins, J. Steven

    2006-01-01

    A vision is presented for fusing quantitative requirements analysis with model-based systems engineering. This vision draws upon and combines emergent themes in the engineering milieu. "Requirements engineering" provides means to explicitly represent requirements (both functional and non-functional) as constraints and preferences on acceptable solutions, and emphasizes early-lifecycle review, analysis and verification of design and development plans. "Design by shopping" emphasizes revealing the space of options available from which to choose (without presuming that all selection criteria have previously been elicited), and provides means to make understandable the range of choices and their ramifications. "Model-based engineering" emphasizes the goal of utilizing a formal representation of all aspects of system design, from development through operations, and provides powerful tool suites that support the practical application of these principles. A first step prototype towards this vision is described, embodying the key capabilities. Illustrations, implications, further challenges and opportunities are outlined.

  19. Note: Discharging fused silica test masses with ionized nitrogen

    NASA Astrophysics Data System (ADS)

    Ugolini, D.; Funk, Q.; Amen, T.

    2011-04-01

    We have developed a technique for discharging fused silica test masses in a gravitational-wave interferometer with nitrogen ionized by an electron beam. The electrons are produced from a heated filament by thermionic emission in a low-pressure region to avoid contamination and burnout. Some electrons then pass through a small aperture and ionize nitrogen in a higher-pressure region, and this ionized gas is pumped across the test mass surface, neutralizing both polarities of charge. The discharge rate varies exponentially with charge density and filament current, quadratically with filament potential, and has an optimal working pressure of ˜8 mT. Adapting the technique to larger test mass chambers is also discussed.

  20. Facade model refinement by fusing terrestrial laser data and image

    NASA Astrophysics Data System (ADS)

    Liu, Yawen; Qin, Sushun

    2015-12-01

    The building facade model is one of main landscapes of a city and basic data of city geographic information. It is widely useful in accurate path planning, real navigation through the urban environment, location-based application, etc. In this paper, a method of facade model refinement by fusing terrestrial laser data and image is presented. It uses the matching of model edge and image line combined with laser data verification and effectively refines facade geometry model that reconstructed from laser data. The laser data of geometric structures on building facade such as window, balcony and door are segmented, and used as a constraint for further selecting the optical model edges that are located at the cross-line of point data and no data. The results demonstrate the deviation of model edges caused by laser sampling interval can be removed in the proposed method.

  1. SCALABLE FUSED LASSO SVM FOR CONNECTOME-BASED DISEASE PREDICTION

    PubMed Central

    Watanabe, Takanori; Scott, Clayton D.; Kessler, Daniel; Angstadt, Michael; Sripada, Chandra S.

    2015-01-01

    There is substantial interest in developing machine-based methods that reliably distinguish patients from healthy controls using high dimensional correlation maps known as functional connectomes (FC's) generated from resting state fMRI. To address the dimensionality of FC's, the current body of work relies on feature selection techniques that are blind to the spatial structure of the data. In this paper, we propose to use the fused Lasso regularized support vector machine to explicitly account for the 6-D structure of the FC (defined by pairs of points in 3-D brain space). In order to solve the resulting nonsmooth and large-scale optimization problem, we introduce a novel and scalable algorithm based on the alternating direction method. Experiments on real resting state scans show that our approach can recover results that are more neuroscientifically informative than previous methods. PMID:25892971

  2. FUSE Spectroscopy of the Accreting Hot Components in Symbiotic Variables

    NASA Astrophysics Data System (ADS)

    Sion, Edward M.; Godon, Patrick; Mikolajewska, Joanna; Sabra, Bassem; Kolobow, Craig

    2017-04-01

    We have conducted a spectroscopic analysis of the far-ultraviolet archival spectra of four symbiotic variables, EG And, AE Ara, CQ Dra, and RW Hya. RW Hya and EG And have never had a recorded outburst, while CQ Dra and AE Ara have outburst histories. We analyze these systems while they are in quiescence in order to help reveal the physical properties of their hot components via comparisons of the observations with optically thick accretion disk models and non-LTE model white dwarf photospheres. We have extended the wavelength coverage down to the Lyman limit with Far Ultraviolet Spectroscopic Explorer (FUSE) spectra. We find that the hot component in RW Hya is a low-mass white dwarf with a surface temperature of 160,000 K. We reexamine whether or not the symbiotic system CQ Dra is a triple system with a red giant transferring matter to a hot component made up of a cataclysmic variable in which the white dwarf has a surface temperature as low as ∼20,000 K. The very small size of the hot component contributing to the shortest wavelengths of the FUSE spectrum of CQ Dra agrees with an optically thick and geometrically thin (∼4% of the WD surface) hot (∼120,000 K) boundary layer. Our analysis of EG And reveals that its hot component is a hot, bare, low-mass white dwarf with a surface temperature of 80,000–95,000 K, with a surface gravity {log}(g)=7.5. For AE Ara, we also find that a low-gravity ({log}(g)∼ 6), hot (T∼ {{130,000}} K) WD accounts for the hot component.

  3. Modeling Disease Progression via Fused Sparse Group Lasso

    PubMed Central

    Zhou, Jiayu; Liu, Jun; Narayan, Vaibhav A.; Ye, Jieping

    2013-01-01

    Alzheimer’s Disease (AD) is the most common neurodegenerative disorder associated with aging. Understanding how the disease progresses and identifying related pathological biomarkers for the progression is of primary importance in the clinical diagnosis and prognosis of Alzheimer’s disease. In this paper, we develop novel multi-task learning techniques to predict the disease progression measured by cognitive scores and select biomarkers predictive of the progression. In multi-task learning, the prediction of cognitive scores at each time point is considered as a task, and multiple prediction tasks at different time points are performed simultaneously to capture the temporal smoothness of the prediction models across different time points. Specifically, we propose a novel convex fused sparse group Lasso (cFSGL) formulation that allows the simultaneous selection of a common set of biomarkers for multiple time points and specific sets of biomarkers for different time points using the sparse group Lasso penalty and in the meantime incorporates the temporal smoothness using the fused Lasso penalty. The proposed formulation is challenging to solve due to the use of several non-smooth penalties. One of the main technical contributions of this paper is to show that the proximal operator associated with the proposed formulation exhibits a certain decomposition property and can be computed efficiently; thus cFSGL can be solved efficiently using the accelerated gradient method. To further improve the model, we propose two non-convex formulations to reduce the shrinkage bias inherent in the convex formulation. We employ the difference of convex (DC) programming technique to solve the non-convex formulations. We have performed extensive experiments using data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Results demonstrate the effectiveness of the proposed progression models in comparison with existing methods for disease progression. We also perform

  4. Thermal annealing of laser damage precursors on fused silica surfaces

    SciTech Connect

    Shen, N; Miller, P E; Bude, J D; Laurence, T A; Suratwala, T I; Steele, W A; Feit, M D; Wang, L L

    2012-03-19

    Previous studies have identified two significant precursors of laser damage on fused silica surfaces at fluenes below {approx} 35 J/cm{sup 2}, photoactive impurities in the polishing layer and surface fractures. In the present work, isothermal heating is studied as a means of remediating the highly absorptive, defect structure associated with surface fractures. A series of Vickers indentations were applied to silica surfaces at loads between 0.5N and 10N creating fracture networks between {approx} 10{micro}m and {approx} 50{micro}m in diameter. The indentations were characterized prior to and following thermal annealing under various times and temperature conditions using confocal time-resolved photo-luminescence (CTP) imaging, and R/1 optical damage testing with 3ns, 355nm laser pulses. Significant improvements in the damage thresholds, together with corresponding reductions in CTP intensity, were observed at temperatures well below the glass transition temperature (T{sub g}). For example, the damage threshold on 05.N indentations which typically initiates at fluences <8 J/cm{sup 2} could be improved >35 J/cm{sup 2} through the use of a {approx} 750 C thermal treatment. Larger fracture networks required longer or higher temperature treatment to achieve similar results. At an annealing temperature > 1100 C, optical microscopy indicates morphological changes in some of the fracture structure of indentations, although remnants of the original fracture and significant deformation was still observed after thermal annealing. This study demonstrates the potential of using isothermal annealing as a means of improving the laser damage resistance of fused silica optical components. Similarly, it provides a means of further understanding the physics associated with optical damage and related mitigation processes.

  5. Using conceptual spaces to fuse knowledge from heterogeneous robot platforms

    NASA Astrophysics Data System (ADS)

    Kira, Zsolt

    2010-04-01

    As robots become more common, it becomes increasingly useful for many applications to use them in teams that sense the world in a distributed manner. In such situations, the robots or a central control center must communicate and fuse information received from multiple sources. A key challenge for this problem is perceptual heterogeneity, where the sensors, perceptual representations, and training instances used by the robots differ dramatically. In this paper, we use Gärdenfors' conceptual spaces, a geometric representation with strong roots in cognitive science and psychology, in order to represent the appearance of objects and show how the problem of heterogeneity can be intuitively explored by looking at the situation where multiple robots differ in their conceptual spaces at different levels. To bridge low-level sensory differences, we abstract raw sensory data into properties (such as color or texture categories), represented as Gaussian Mixture Models, and demonstrate that this facilitates both individual learning and the fusion of concepts between robots. Concepts (e.g. objects) are represented as a fuzzy mixture of these properties. We then treat the problem where the conceptual spaces of two robots differ and they only share a subset of these properties. In this case, we use joint interaction and statistical metrics to determine which properties are shared. Finally, we show how conceptual spaces can handle the combination of such missing properties when fusing concepts received from different robots. We demonstrate the fusion of information in real-robot experiments with a Mobile Robots Amigobot and Pioneer 2DX with significantly different cameras and (on one robot) a SICK lidar.ÿÿÿÿ

  6. Procyon experiments utilizing foil-fuse opening switches

    SciTech Connect

    Rickel, D.G.; Lindemuth, I.R.; Reinovsky, R.E.; Brownell, J.H.; Goforth, J.H.; Greene, A.E.; Kruse, H.W.; Oona, H.; Parker, J.V.; Turchi, P.J.

    1991-01-01

    The Los Alamos National Laboratory has applied the explosive magnetic flux compression generator (FCG) technology to the high-energy foil-implosion project, Trailmaster, to reach energy levels unattainable by other methods under current budget constraints. A required component for FCG systems is a power-conditioning stage that matches the slow risetime of the energy source with the fast-risetime requirements of the foil-implosion load. Currently, the Trailmaster concept is based on a two-step process of combining an intermediate power compression stage with a plasma flow switch (PFS) that will deliver energy to an imploding foil on the order of 100 ns. The intermediate power compression stage, which is the main emphasis of this report, consists of an energy storage inductor loaded by the FCG (the energy sauce) and an associated opening and closing switch. In our Procyon testing series, a subtask of the Trailmaster project, we have explored two approaches for opening and closing switches. One uses an explosive opening switch (EFF) and a detonator-initiated closing switch, the topic of another paper at this conference, and the other a resistive fuse opening switch a surface tracking closing switch (STS), the subject of this presentation. This latter concept was successfully tested last summer with a complete plasma flow switch assembly except the dynamic implosion foil was replaced by a rigid passive inductive load. We present data on the performance of the fuse opening switch, the surface tracking closing switch, and the plasma flow switch. 7 refs., 9 figs.

  7. Characteristics Of Fused Couplers Below Cut-Off

    NASA Astrophysics Data System (ADS)

    Meyer, T. J.; Tekippe, V. J.

    1989-02-01

    A number of different architectures are being explored for the utilization of optical fiber in the subscriber loop. In addition to reliability and maintainability, cost is a prime consideration since full implementation of fiber in the local loop will not occur until it is economically viable. It is becoming increasingly clear that in order to accommodate a number of ISDN applications, including high definition television (HDTV), singlemode fiber with a singlemode laser at the terminal end will be required. The situation at the subscriber end is quite different, however. The data rates are expected to be low on the return path to allow for POTS ( plain old telephone service) and some data transfer. When this requirement is combined with cost and reliability considerations, the inexpensive lasers developed for the CD (compact disk) market become quite attractive. The biggest disadvantage of this source is that the fiber which is optimized for singlemode operation at 1300nm tends to be multimode in the 800nm band where these lasers operate. Previous papers have considered such effects as modal noise and pulse dispersion when using these lasers with fiber that is singlemode in the 1300nm band.[1] Another consideration is the passive components required to implement such an architecture. Figure 1 shows a typical bidirectional design with full duplex operation on a single fiber. The key component is the 800/1300 wavelength division multiplexer/demultiplexer (WDM). Because of the multimode nature of the fiber in the 800nm band, all fiber approaches to fabricating the WDM, such as the fused beconical taper (FBT) approach, raise new issues which are not encountered, for example, with 1300/1500nm WDM's.[2] In this paper we discuss the effects of the multimode behavior of the fiber on the performance of fused couplers and WDM's.

  8. 49 CFR 1.3 - Exercise of authority.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Exercise of authority. 1.3 Section 1.3... § 1.3 Exercise of authority. (a) In exercising powers and performing duties delegated by this part or..., the Assistant Secretaries, the Inspector General, and the Administrators exercise the powers...

  9. 49 CFR 1.3 - Exercise of authority.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Exercise of authority. 1.3 Section 1.3... § 1.3 Exercise of authority. (a) In exercising powers and performing duties delegated by this part or..., the Assistant Secretaries, the Inspector General, and the Administrators exercise the powers...

  10. 49 CFR 1.3 - Exercise of authority.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 1 2013-10-01 2013-10-01 false Exercise of authority. 1.3 Section 1.3... § 1.3 Exercise of authority. (a) In exercising powers and performing duties delegated by this part or..., the Assistant Secretaries, the Inspector General, and the Administrators exercise the powers...

  11. 14 CFR 1.3 - Rules of construction.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Rules of construction. 1.3 Section 1.3 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION DEFINITIONS DEFINITIONS AND ABBREVIATIONS § 1.3 Rules of construction. (a) In Subchapters A through K of this chapter,...

  12. 7 CFR 1.3 - Agency implementing regulations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Agency implementing regulations. 1.3 Section 1.3 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Official Records § 1.3 Agency implementing regulations. Each agency of the Department shall promulgate regulations setting forth...

  13. 7 CFR 1.3 - Agency implementing regulations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false Agency implementing regulations. 1.3 Section 1.3 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Official Records § 1.3 Agency implementing regulations. Each agency of the Department shall promulgate regulations setting forth...

  14. 43 CFR 3862.1-3 - Evidence of title.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Evidence of title. 3862.1-3 Section 3862.1-3 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL PATENT APPLICATIONS Lode Mining Claim Patent Applications § 3862.1-3 Evidence of...

  15. 43 CFR 3862.1-3 - Evidence of title.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Evidence of title. 3862.1-3 Section 3862.1-3 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL PATENT APPLICATIONS Lode Mining Claim Patent Applications § 3862.1-3 Evidence of...

  16. 43 CFR 3862.1-3 - Evidence of title.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Evidence of title. 3862.1-3 Section 3862.1-3 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL PATENT APPLICATIONS Lode Mining Claim Patent Applications § 3862.1-3 Evidence of...

  17. The industrial production and use of 1,3-butadiene.

    PubMed Central

    Morrow, N L

    1990-01-01

    This presentation provides a brief overview of the production and use of 1,3-butadiene in the United States. Starting as a coproduct of ethylene, the 1,3-butadiene monomer is extracted and purified, then transferred to consumers. Major uses of 1,3-butadiene include the manufacture of styrene-butadiene rubber, polybutadiene rubber, and adiponitrile. PMID:2205493

  18. 49 CFR 1.3 - Organization of the Department.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Organization of the Department. 1.3 Section 1.3 Transportation Office of the Secretary of Transportation ORGANIZATION AND DELEGATION OF POWERS AND DUTIES General § 1.3 Organization of the Department. (a) The Secretary of Transportation is the head of...

  19. Direct, Regioselective N-Alkylation of 1,3-Azoles.

    PubMed

    Chen, Shuai; Graceffa, Russell F; Boezio, Alessandro A

    2016-01-04

    Regioselective N-alkylation of 1,3-azoles is a valuable transformation. Organomagnesium reagents were discovered to be competent bases to affect regioselective alkylation of various 1,3-azoles. Counterintuitively, substitution selectively occurred at the more sterically hindered nitrogen atom. Numerous examples are provided, on varying 1,3-azole scaffolds, with yields ranging from 25 to 95%.

  20. 10 CFR 960.3-1-3 - Regionality.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Regionality. 960.3-1-3 Section 960.3-1-3 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-3 Regionality. In making site recommendations for...

  1. 10 CFR 960.3-1-3 - Regionality.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Regionality. 960.3-1-3 Section 960.3-1-3 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-3 Regionality. In making site recommendations for...

  2. 10 CFR 960.3-1-3 - Regionality.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Regionality. 960.3-1-3 Section 960.3-1-3 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-3 Regionality. In making site recommendations for...

  3. 10 CFR 960.3-1-3 - Regionality.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Regionality. 960.3-1-3 Section 960.3-1-3 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-3 Regionality. In making site recommendations for...

  4. 10 CFR 960.3-1-3 - Regionality.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Regionality. 960.3-1-3 Section 960.3-1-3 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-3 Regionality. In making site recommendations for...

  5. Fluorescence properties and dipole moments of novel fused thienobenzofurans. Solvent and structural effects.

    PubMed

    Aaron, Jean-Jacques; Párkányi, Cyril; Adenier, Alain; Potin, Caroline; Zajíčková, Zuzana; Martínez, Omar R; Svoboda, Jiří; Pihera, Pavel; Váchal, Petr

    2011-11-01

    The electronic absorption, fluorescence excitation and emission spectra, and fluorescence quantum yields of novel fused thienobenzofurans, including thieno[3,2-b][1]benzofuran (1), [1]benzothieno[3,2-b]furan (2), and [1]benzothieno[3,2-b][1]benzofuran (3), were recorded in fourteen solvents of different polarities at room temperature. Compound 2 was not fluorescent. Experimental ground-state dipole moments of compounds 1-3 were measured in benzene at 298 K and compared with the corresponding theoretical dipole moment values. The solvent effects on the electronic absorption and fluorescence spectra of these thienobenzofurans were quantitatively investigated by means of solvatochromic correlations based on the Kawski-Chamma-Viallet and McRae equations. A weak negative solvatochromic behavior was found for these compounds, showing that their dipole moments are slightly lower in the excited singlet-state than in the ground-state. Kamlet-Abboud-Taft multiparameter relationships were also established for electronic absorption and fluorescence wavenumbers, and fluorescence quantum yields in most solvents, demonstrating the occurrence of specific solute-solvent interactions.

  6. Identification and enzymatic characterization of an endo-1,3-β-glucanase from Euglena gracilis.

    PubMed

    Takeda, Takumi; Nakano, Yuki; Takahashi, Machiko; Konno, Naotake; Sakamoto, Yuichi; Arashida, Ryo; Marukawa, Yuka; Yoshida, Eriko; Ishikawa, Takahiro; Suzuki, Kengo

    2015-08-01

    Euglena produces paramylon as a storage polysaccharide, and is thought to require β-1,3-glucan degrading enzymes to release and utilize the accumulated carbohydrate. To investigate β-1,3-glucan degradation in Euglena, endo-1,3-β-glucanases were partially purified from Euglena gracilis by hydrophobic, gel filtration and anion-exchange chromatography. Tryptic digests and mass-spectrometric analysis identified three proteins in the purified fraction as a member of glycoside hydrolase family (GH) 17 and two members of GH81. These genes were cloned from an Euglena cDNA pool by PCR. EgCel17A fused with a histidine-tag at the carboxy terminus was heterologously produced by Aspergillus oryzae and purified by immobilized metal affinity chromatography. Purified EgCel17A had a molecular weight of about 40kDa by SDS-PAGE, which was identical to that deduced from its amino acid sequence. The enzyme showed hydrolytic activity towards β-1,3-glucans such as laminarin and paramylon. Maximum activity of laminarin degradation by EgCel17A was attained at pH 4.0-5.5 and 60°C after 1h incubation or 50°C after 20h incubation. The enzyme had a Km of 0.21mg/ml and a Vmax of 40.5units/mg protein for laminarin degradation at pH 5.0 and 50°C. Furthermore, EgCel17A catalyzed a transglycosylation reaction by which reaction products with a higher molecular weight than the supplied substrates were initially generated; however, ultimately the substrates were degraded into glucose, laminaribiose and laminaritriose. EgCel17A effectively produced soluble β-1,3-glucans from alkaline-treated Euglena freeze-dried powder containing paramylon. Thus, EgCel17 is the first functional endo-1,3-β-glucanase to be identified from E. gracilis.

  7. FUSE and STIS Observations of Highly Ionized Gas along the Line of Sight towards HD 116852

    NASA Astrophysics Data System (ADS)

    Fox, A. J.; Savage, B. D.; Fabian, D.; Richter, P.; Sembach, K. R.; Meyer, D. M.; Lauroesch, J.; Howk, J. C.

    2002-05-01

    We present Space Telescope Imaging Spectrograph (STIS) and Far-Ultraviolet Spectroscopic Explorer (FUSE) observations of high ion interstellar ultraviolet absorption along the sight line to HD 116852. At a distance of 4.8 kpc, HD 116852 is an O9 III star lying in the low Galactic halo, -1.3 kpc from the plane of the Galaxy in the direction l = 304.9o, b = -6.1o. The sight line passes underneath the Sagittarius-Carina and the Norma-Centaurus spiral arms. The STIS E140H grating observations provide high-resolution (FWHM ≈ 2.7 km s-1) spectra of the resonance doublets of Si 4, C 4 and N 5. These data are complemented by medium-resolution (FWHM ≈ 20 km s-1) FUSE spectra of O 6. We find evidence for three distinct types of absorbing gas present in the data. First, two narrow absorption components are resolved in the Si 4 and \\ion {C}{4} profiles, at approximate LSR velocities of -36 and -10 km s-1. These narrow components appear to be produced in gas associated with the Norma and Sagittarius spiral arms, at approximate z-distances of -1.0 and -0.5 kpc respectively. The temperature of the gas in in these narrow components, as implied by their b-values, suggests that the gas is photoionized. The ratio of C 4 to Si 4 in these narrow components is low compared to the Galactic average. Second, we detect an intermediate-width component in C 4 and Si 4, at +17 km s-1, which we propose could arise at the conductive interface at the boundary between a dense cloud and the surrounding medium. Finally, a broad collisionally ionized component of gas responsible for producing the smooth N 5 and O 6 profiles is observed; such absorption is also present to a lesser degree in the profiles of Si 4 and \\ion {C}{4}. The broad O 6 absorption is observed at a velocity displaced from the C 4 profile by almost 20 km s-1, an amount large enough to suggest that the two ions may not co-exist in the same physical location. If these two ions do exist together, then the ratio N(C 4)/N(O 6) is

  8. Performance oriented packaging report for ignitor, time blasting fuse, weatherproof: M60. Final report

    SciTech Connect

    Sniezek, F.

    1992-11-02

    This POP report is for the Time Blasting Fuse, Weatherproof: M60 which is packaged 300/ Mil-B-2427 wood box. This report describes the results of testing conducted.... Performance oriented packaging, POP, Time blasting fuse, Weatherproof: M60 Mil-B-2427 wood box.

  9. Performance oriented packaging report for fuse, blasting, time, M700. Final report

    SciTech Connect

    Sniezek, F.M.

    1992-11-02

    This POP report is for the Fuse, Blasting, Time, M700 which is packaged 4000 feet/ Mil-B-2427 wood box. This report describes the results of testing conducted on a similar packaging which is used as an analogy for this item....Performance oriented packaging, POP, Fuse, Blasting, Time, M700, Mil-B-2427 Wood box.

  10. Relationship between industrial discharges and contamination of raw water resources by perfluorinated compounds: part II: Case study of a fluorotelomer polymer manufacturing plant.

    PubMed

    Dauchy, Xavier; Boiteux, Virginie; Rosin, Christophe; Munoz, Jean-François

    2012-09-01

    In this study, the concentrations of 10 perfluorinated compounds (PFCs) were measured in effluents of a fluorotelomer polymer manufacturing plant and its wastewater treatment plant. A 50-fold increase between the two effluents mass flows was observed. The water quality of two drinking water treatment plants located downstream at 15 and 25 km from the manufacturing plant was examined. An increase of the sum of PFCs was observed between the river (30 ng/L) and an alluvial well (70 ng/L), and between the raw water (9 ng/L) and the outlet of a biological treatment (97 ng/L). These results indicate a possible degradation of fluorotelomers, occurring during wastewater treatment, sediment infiltration in the alluvial aquifer, and drinking water treatment.

  11. Relationship between industrial discharges and contamination of raw water resources by perfluorinated compounds. Part I: Case study of a fluoropolymer manufacturing plant.

    PubMed

    Dauchy, Xavier; Boiteux, Virginie; Rosin, Christophe; Munoz, Jean-François

    2012-09-01

    Perfluorinated compounds (PFCs) have been recognized as global environmental pollutants. They are used in various applications and high levels have been found in water bodies located near highly industrialized sites. In the present study, 10 PFCs were quantitatively determined in water samples collected in the vicinity of a fluoropolymer manufacturing plant and in drinking water resources located downstream. The release of PFHxA and PFNA to the receiving river was estimated at 10 and 4.5 tons/year, respectively. PFHxA (0.058-0.156 μg/L), PFNA (0.013-0.035 μg/L) and PFOA (0.007-0.025 μg/L) were predominant and prevalent in all the studied drinking water resources, confirming with the composition profile the impact of the industrial park release.

  12. Enhancing the Brightness of Cesium Lead Halide Perovskite Nanocrystal Based Green Light-Emitting Devices through the Interface Engineering with Perfluorinated Ionomer.

    PubMed

    Zhang, Xiaoyu; Lin, Hong; Huang, He; Reckmeier, Claas; Zhang, Yu; Choy, Wallace C H; Rogach, Andrey L

    2016-02-10

    High photoluminescence quantum yield, easily tuned emission colors, and high color purity of perovskite nanocrystals make this class of material attractive for light source or display applications. Here, green light-emitting devices (LEDs) were fabricated using inorganic cesium lead halide perovskite nanocrystals as emitters. By introducing a thin film of perfluorinated ionomer (PFI) sandwiched between the hole transporting layer and perovskite emissive layer, the device hole injection efficiency has been significantly enhanced. At the same time, PFI layer suppressed charging of the perovskite nanocrystal emitters thus preserving their superior emissive properties, which led to the three-fold increase in peak brightness reaching 1377 cd m(-2). The full width at half-maximum of the symmetric emission peak with color coordinates of (0.09, 0.76) was 18 nm, the narrowest value among perovskite based green LEDs.

  13. Synthesis, fine structure of 19F NMR and fluorescence of novel amorphous TPA derivatives having perfluorinated cyclopentenyl and benzo[b]thiophene unit

    NASA Astrophysics Data System (ADS)

    Wu, Bian-Peng; Pang, Mei-Li; Tan, Ting-Feng; Meng, Ji-ben

    2013-04-01

    Three novel triphenylamine (TPA) derivatives having perfluorinated cyclopentenyl and benzo[b]thiophene unit are obtained from 4-bromo-N,N-diphenyl-2-methylbenzo[b]thiophen-5-amine. The new compounds are expected to find their use in thin film devices as charge transport materials and host organic light-emitting materials. It is found that the new compounds show relatively strong fluorescence either in solution or in solid state, and are amorphous due to a special conformation which is elucidated by the fine structure of 19F NMR. Molecular structure and properties of these compounds is characterized by 1H NMR, 13C NMR (broadband decoupled), ESI-HRMS, elemental analysis and thermal analysis (DSC). Fluorescent quantum yield in solution is measured using 9,10-diphenylanthrancene (DPA) as standard fluorescent substance.

  14. A food-grade industrial arming yeast expressing beta-1,3-1,4-glucanase with enhanced thermal stability.

    PubMed

    Guo, Qin; Zhang, Wei; Ma, Liu-liu; Chen, Qi-he; Chen, Ji-cheng; Zhang, Hong-bo; Ruan, Hui; He, Guo-qing

    2010-01-01

    The aim of this work was to construct a novel food-grade industrial arming yeast displaying beta-1,3-1,4-glucanase and to evaluate the thermal stability of the glucanase for practical application. For this purpose, a bi-directional vector containing galactokinase (GAL1) and phosphoglycerate kinase 1 (PGK1) promoters in different orientations was constructed. The beta-1,3-1,4-glucanase gene from Bacillus subtilis was fused to alpha-agglutinin and expressed under the control of the GAL1 promoter. alpha-galactosidase induced by the constitutive PGK1 promoter was used as a food-grade selection marker. The feasibility of the alpha-galactosidase marker was confirmed by the growth of transformants harboring the constructed vector on a medium containing melibiose as a sole carbon source, and by the clear halo around the transformants in Congo-red plates owing to the expression of beta-1,3-1,4-glucanase. The analysis of beta-1,3-1,4-glucanase activity in cell pellets and in the supernatant of the recombinant yeast strain revealed that beta-1,3-1,4-glucanase was successfully displayed on the cell surface of the yeast. The displayed beta-1,3-1,4-glucanase activity in the recombinant yeast cells increased immediately after the addition of galactose and reached 45.1 U/ml after 32-h induction. The thermal stability of beta-1,3-1,4-glucanase displayed in the recombinant yeast cells was enhanced compared with the free enzyme. These results suggest that the constructed food-grade yeast has the potential to improve the brewing properties of beer.

  15. PEDOT modified LiNi1/3Co1/3Mn1/3O2 with enhanced electrochemical performance for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Liu, Xizheng; Li, Huiqiao; Li, De; Ishida, Masayoshi; Zhou, Haoshen

    2013-12-01

    Layered LiNi1/3Co1/3Mn1/3O2 was modified by poly(3,4-dioxyethylenethiophene) PEDOT via a facile method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and infrared spectroscopy (IR). PEDOT modified samples exhibited both improved rate and cycle performance compared with the pristine LiNi1/3Co1/3Mn1/3O2. At a charge/discharge current of 1500 mA g-1, the discharge capacity was improved from 44.3 to 73.9 mAh g-1. The sample with 2 wt% and heat treated at 300 °C showed the optimized electrochemical performance. Galvanostatic intermittent titration technique (GITT) and cyclic voltammetry (CV) results indicated that the battery polarization of coated samples have been suppressed obviously because the PEDOT layer facilitated the electron transfer at the interface of electrode and electrolyte.

  16. Calendering effects on the physical and electrochemical properties of Li[Ni1/3Mn1/3Co1/3]O2 cathode

    NASA Astrophysics Data System (ADS)

    Zheng, Honghe; Tan, Li; Liu, Gao; Song, Xiangyun; Battaglia, Vincent S.

    2012-06-01

    Li[Ni1/3Mn1/3Co1/3]O2 cathode laminate containing 8% PVDF and 7% acetylene black is fabricated and calendered to different porosities. Calendering effects on the physical and electrochemical properties of the Li[Ni1/3Mn1/3Co1/3]O2 cathode are investigated. It is found that mechanical properties of the composite laminate strongly depend on the electrode porosity whereas the electronic conductivity is not significantly affected by calendering. Electrochemical performances including the specific capacity, the first coulombic efficiency, cycling performance and rate capability for the cathode at different porosities are compared. An optimized porosity of around 30-40% is identified. Electrochemical impedance spectroscopy (EIS) studies illustrate that calendering improves the electronic conductivity between active particles at relatively high porosities, but increases charge transfer resistance at electrode/electrolyte interface at relatively low porosities. An increase of activation energy of Li interfacial transfer for the electrode at 0% porosity indicates a relatively high barrier of activation at the electrode/electrolyte interface, which accounts for the poor rate capability of the electrode at extremely low porosity.

  17. Capacity improvement by deficit of transition metals in inverse spinel LiNi1/3Co1/3Mn1/3VO4 cathodes

    NASA Astrophysics Data System (ADS)

    Kitajou, Ayuko; Yoshida, Jun; Nakanishi, Shinji; Matsuda, Yasuaki; Kanno, Ryoji; Okajima, Toshihiro; Okada, Shigeto

    2016-01-01

    Although inverse spinel materials have attracted attention because of their unusually high voltage characteristics, their rechargeable capacities are generally less than 50 mAh g-1, as a result of the coexistence of Li and transition metal ions at 16d octahedral sites. This work attempted to improve cathode functioning by optimizing the quantities of Li and transition metal ions residing at the 16d sites of LiNi1/3Co1/3Mn1/3VO4. The rechargeable capacity of the LiNi0.28Co0.28Mn0.26V0.80O4 synthesized in the present study was found to be above 120 mAh g-1, representing the largest capacity reported to date for an inverse spinel material. The results of in-situ XANES analysis demonstrated that the charge-discharge reactions of LiNi1/3Co1/3Mn1/3VO4 corresponds to the Mn2+/Mn4+ and Co2+/Co3+ redox couples, mainly.

  18. Real-time locating and speed measurement of fibre fuse using optical frequency-domain reflectometry

    PubMed Central

    Jiang, Shoulin; Ma, Lin; Fan, Xinyu; Wang, Bin; He, Zuyuan

    2016-01-01

    We propose and experimentally demonstrate real-time locating and speed measurement of fibre fuse by analysing the Doppler shift of reflected light using optical frequency-domain reflectometry (OFDR). Our method can detect the start of a fibre fuse within 200 ms which is equivalent to a propagation distance of about 10 cm in standard single-mode fibre. We successfully measured instantaneous speed of propagating fibre fuses and observed their subtle fluctuation owing to the laser power instability. The resolution achieved for speed measurement in our demonstration is 1 × 10−3 m/s. We studied the fibre fuse propagation speed dependence on the launched power in different fibres. Our method is promising for both real time fibre fuse monitoring and future studies on its propagation and termination. PMID:27146550

  19. Modification of nanostructured fused silica for use as superhydrophobic, IR-transmissive, anti-reflective surfaces

    NASA Astrophysics Data System (ADS)

    Boyd, Darryl A.; Frantz, Jesse A.; Bayya, Shyam S.; Busse, Lynda E.; Kim, Woohong; Aggarwal, Ishwar; Poutous, Menelaos; Sanghera, Jasbinder S.

    2016-04-01

    In order to mimic and enhance the properties of moth eye-like materials, nanopatterned fused silica was chemically modified to produce self-cleaning substrates that have anti-reflective and infrared transmissive properties. The characteristics of these substrates were evaluated before and after chemical modification. Furthermore, their properties were compared to fused silica that was devoid of surface features. The chemical modification imparted superhydrophobic character to the substrates, as demonstrated by the average water contact angles which exceeded 170°. Finally, optical analysis of the substrates revealed that the infrared transmission capabilities of the fused silica substrates (nanopatterned to have moth eye on one side) were superior to those of the regular fused silica substrates within the visible and near-infrared region of the light spectrum, with transmission values of 95% versus 92%, respectively. The superior transmission properties of the fused silica moth eye were virtually unchanged following chemical modification.

  20. Refractive index sensors based on the fused tapered special multi-mode fiber

    NASA Astrophysics Data System (ADS)

    Fu, Xing-hu; Xiu, Yan-li; Liu, Qin; Xie, Hai-yang; Yang, Chuan-qing; Zhang, Shun-yang; Fu, Guang-wei; Bi, Wei-hong

    2016-01-01

    In this paper, a novel refractive index (RI) sensor is proposed based on the fused tapered special multi-mode fiber (SMMF). Firstly, a section of SMMF is spliced between two single-mode fibers (SMFs). Then, the SMMF is processed by a fused tapering machine, and a tapered fiber structure is fabricated. Finally, a fused tapered SMMF sensor is obtained for measuring external RI. The RI sensing mechanism of tapered SMMF sensor is analyzed in detail. For different fused tapering lengths, the experimental results show that the RI sensitivity can be up to 444.517 81 nm/RIU in the RI range of 1.334 9—1.347 0. The RI sensitivity is increased with the increase of fused tapering length. Moreover, it has many advantages, including high sensitivity, compact structure, fast response and wide application range. So it can be used to measure the solution concentration in the fields of biochemistry, health care and food processing.