WorldWideScience

Sample records for aromatics saturation opening

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

    Institute of Scientific and Technical Information of China (English)

    张轩; 徐亮; 王希涛; 马宁; 孙菲菲

    2012-01-01

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

  2. Saturated and aromatic diterpenoids and triterpenoids in Eocene coals and mudstones from China

    Energy Technology Data Exchange (ETDEWEB)

    Tuo, J.C.; Philp, R.P. [Chinese Academy of Science, Gansu (China)

    2005-02-01

    Several series of saturated, diaromatic, triaromatic C-ring cleaved and triaromatic diterpenoids and triterpernoids have been detected in 4 immature coal and mudstone samples. A number of these compounds appear to represent intermediates in a series of postulated pathways for progressive aromatization of biogenic diterpenoids and triterpenoids. Diagenetic pathways for the formation of tricyclic aromatic hydrocarbons from abietane and pimarane type diterpenoid precursors and for the formation of diaromatic, triaromatic C-cleaved and triaromatic hydrocarbons from P-amyrin and other triterpenoid precursors are proposed. Saturated and aromatized abietanes, pimaranes and phyllocladanes, which are the most abundant compounds in all 4 samples, indicate a predominant higher plant input which can be related to the Coniferales group but not to individual plant families. beta-Amyrin and other triterpenoid-derived triaromatic and triaromatic C-ring cleaved hydrocarbons with triterpenoid structures are thought to be characteristic for angiosperms. The relative concentrations of the triaromatic and triaromatic C-ring cleaved hydrocarbons are higher in samples 9602 (mudstone) and 9603 (coal) than samples 9601 (coal) and 9604 (mudstone) indicating samples 9602 (mudstone) and 9603 (coal) contain relatively more angiosperm derived organic matter than samples 9601 (coal) and 9604 (mudstone). The distribution patterns and the relative concentrations of saturated and aromatic diterpenoids and triterpenoids thus are valuable markers for the determination of the relative contents of biological sources of organic material in geological samples.

  3. Saturated and aromatic diterpenoids and triterpenoids in Eocene coals and mudstones from China

    Energy Technology Data Exchange (ETDEWEB)

    Jincai Tuo [Chinese Academy of Sciences, Lanzhou (China). Inst. of Geology; Philp, R.P. [Oklahoma Univ., Norman, OK (United States). School of Geology and Geophysics

    2005-02-01

    Several series of saturated, diaromatic, triaromatic C-ring cleaved and triaromatic diterpenoids and triterpenoids have been detected in 4 immature coal and mudstone samples. A number of these compounds appear to represent intermediates in a series of postulated pathways for progressive aromatization of biogenic diterpenoids and triterpenoids. Diagenetic pathways for the formation of tricyclic aromatic hydrocarbons from abietane and pimarane type diterpenoid precursors and for the formation of diaromatic, triaromatic C-cleaved and triaromatic hydrocarbons from {beta}-amyrin and other triterpenoid precursors are proposed. Saturated and aromatized abietanes, pimaranes and phyllocladanes, which are the most abundant compounds in all 4 samples, indicate a predominant higher plant input which can be related to the Coniferales group but not to individual plant families. {beta}-Amyrin and other triterpenoid-derived triaromatic and triaromatic C-ring cleaved hydrocarbons with triterpenoid structures are thought to be characteristic for angiosperms. The relative concentrations of the triaromatic and triaromatic C-ring cleaved hydrocarbons are higher in samples 9602 (mudstone) and 9603 (coal) than samples 9601 (coal) and 9604 (mudstone) indicating samples 9602 (mudstone) and 9603 (coal) contain relatively more angiosperm derived organic matter than samples 9601 (coal) and 9604 (mudstone). The distribution patterns and the relative concentrations of saturated and aromatic diterpenoids and triterpenoids thus are valuable markers for the determination of the relative contents of biological sources of organic material in geological samples. (author)

  4. Sequential Isolation of Saturated, Aromatic, Resinic and Asphaltic Fractions Degrading Bacteria from Oil Contaminated Soil in South Sumatera

    OpenAIRE

    Pingkan Aditiawati; Munawar; Dea Indriani Astuti

    2012-01-01

    Sequential isolation has been conducted to obtain isolates of saturated, aromatic, resin, and asphaltene fractions degrading bacteria from oil contaminated sites. Five soil samples were collected from South Sumatera. These were analyzed using soil extract medium enriched with oil recovery or Remaining-Oil recovery Degradated (ROD) as sole carbon and energy sources according to the isolation stage. ROD at the end of every isolation stage analyzed oil fractions by use of the SARA analysis metho...

  5. Open ended-coaxial Cable Measurements of Saturated Sandy Soils

    Directory of Open Access Journals (Sweden)

    Alberto Godio

    2007-01-01

    Full Text Available The application of electromagnetic methods in the radar and micro-wave frequency band allows the fluid content of soils to be estimated; the heuristic or physically-based models permit to relate the observed electrical permittivity of the soils with the porosity and fluid saturation. The role of the effect of the free water and bound water in the overall electromagnetic behaviour of soils is discussed. The measurements of the complex electrical permittivity of samples with different fluid content were carried out using an open ended coaxial cable in the frequency range between 0.2 and 6 GHz. The data processing permitted to estimate the water content with good accuracy; the slight overestimate of the values with respect to the standard laboratory measures of the fluid content is due to the propagation of the experimental uncertainties and to the effect of the bound water.

  6. Comparison of pulseoximetry oxygen saturation and arterial oxygen saturation in open heart intensive care unit

    Directory of Open Access Journals (Sweden)

    Alireza Mahoori

    2013-08-01

    Full Text Available Background: Pulseoximetry is widely used in the critical care setting, currently used to guide therapeutic interventions. Few studies have evaluated the accuracy of SPO2 (puls-eoximetry oxygen saturation in intensive care unit after cardiac surgery. Our objective was to compare pulseoximetry with arterial oxygen saturation (SaO2 during clinical routine in such patients, and to examine the effect of mild acidosis on this relationship.Methods: In an observational prospective study 80 patients were evaluated in intensive care unit after cardiac surgery. SPO2 was recorded and compared with SaO2 obtained by blood gas analysis. One or serial arterial blood gas analyses (ABGs were performed via a radial artery line while a reliable pulseoximeter signal was present. One hundred thirty seven samples were collected and for each blood gas analyses, SaO2 and SPO2 we recorded.Results: O2 saturation as a marker of peripheral perfusion was measured by Pulseoxim-etry (SPO2. The mean difference between arterial oxygen saturation and pulseoximetry oxygen saturation was 0.12%±1.6%. A total of 137 paired readings demonstrated good correlation (r=0.754; P<0.0001 between changes in SPO2 and those in SaO2 in samples with normal hemoglobin. Also in forty seven samples with mild acidosis, paired readings demonstrated good correlation (r=0.799; P<0.0001 and the mean difference between SaO2 and SPO2 was 0.05%±1.5%.Conclusion: Data showed that in patients with stable hemodynamic and good signal quality, changes in pulseoximetry oxygen saturation reliably predict equivalent changes in arterial oxygen saturation. Mild acidosis doesn’t alter the relation between SPO2 and SaO2 to any clinically important extent. In conclusion, the pulse oximeter is useful to monitor oxygen saturation in patients with stable hemodynamic.

  7. Sequential Isolation of Saturated, Aromatic, Resinic and Asphaltic Fractions Degrading Bacteria from Oil Contaminated Soil in South Sumatera

    Directory of Open Access Journals (Sweden)

    Pingkan Aditiawati

    2012-04-01

    Full Text Available Sequential isolation has been conducted to obtain isolates of saturated, aromatic, resin, and asphaltene fractions degrading bacteria from oil contaminated sites. Five soil samples were collected from South Sumatera. These were analyzed using soil extract medium enriched with oil recovery or Remaining-Oil recovery Degradated (ROD as sole carbon and energy sources according to the isolation stage. ROD at the end of every isolation stage analyzed oil fractions by use of the SARA analysis method. Six isolates of bacteria have been selected, one isolate was fraction saturates degrading bacteria that are Mycobacterium sp. T1H2D4-7 at degradation rate 0.0199 mgs/h with density 8.4x106 cfu/g from stage I. The isolate T2H1D2-4, identified as Pseudomonas sp. was fraction aromatics degrading bacteria at accelerate 0.0141 mgs/h with density 5.1x106 cfu/g are obtained at stage II. Two isolates namely Micrococcus sp. T3H2D4-2 and Pseudomonas sp. T1H1D5-5 were fraction resins degrading bacteria by accelerate 0.0088 mgs/h at density 5.6x106 cfu/g and 0.0089 mgs/h at density 5.7x106 cfu/g are obtained at stage III. Isolation of stage IV has been obtained two isolates Pseudomonas sp. T4H1D3-1and Pseudomonas sp. T4H3D5-4 were fraction asphaltenes degrading bacteria by accelerate 0.0057 mgs/h at density 5.6x106 cfu/g and accelerate 0.0058 mgs/h at density 5.7x106 cfu/g.

  8. Saturable Nonlinearity in Photovoltaic-Photorefractive Crystals Under Open-circuit Condition

    Institute of Scientific and Technical Information of China (English)

    GUO Ru; LING Zhen-Fang; CHEN Xiao-Hu; ZHANG Guo-Quan; ZHANG Xin-Zheng; WEN Hai-Dong; JIANG Ying; LIU Si-Min

    2000-01-01

    We show that the refractive index change induced by a focused incident beam with an additional incoherent uniform illumination in photovoltaic-photorefractive crystals under open-circuit condition has a saturable nonlinearity form. The incoherent uniform background illumination can be used to increase the effective dark irradiance. The formation time of the photovoltaic soliton can be decreased by keeping the intensity of the soliton at a higher value without over-saturation by use of the background illumination.

  9. Analysis of saturated and aromatic hydrocarbons migrating from a polyolefin-based hot-melt adhesive into food.

    Science.gov (United States)

    Lommatzsch, Martin; Biedermann, Maurus; Grob, Koni; Simat, Thomas J

    2016-03-01

    Hot-melt adhesives are widely utilised to glue cardboard boxes used as food packaging material. They have to comply with the requirements of Article 3 of the European Framework Regulation for food contact materials (1935/2004). The hot melt raw materials analysed mainly consisted of paraffinic waxes, hydrocarbon resins and polyolefins. The hydrocarbon resins, functioning as tackifiers, were the predominant source of hydrocarbons of sufficient volatility to migrate into dry foods: the 18 hydrocarbon resins analysed contained 8.2-118 g kg(-1) saturated and up to 59 g kg(-1) aromatic hydrocarbons eluted from GC between n-C16 and n-C24, substantially more than the paraffinic waxes and the polyolefins. These tackfier resins, especially the oligomers ≤ C24, have been characterised structurally by GC×GC-MS and (1)H-NMR spectroscopy. Migration into food was estimated using a simulating system with polenta as food simulant, which was verified by the analysis of a commercial risotto rice sample packed in a virgin fibre folding box sealed with a hot melt. About 0.5-1.5% of the potentially migrating substances (between n-C16 and n-C24) of a hot melt were found to be transferred into food under storage conditions, which can result in a food contamination in the order of 1 mg kg(-1) food (depending on the amount of potentially migrating substances from the hot melt, the hot melt surface, amount of food, contact time etc.). Migrates from hot melts are easily mistaken for mineral oil hydrocarbons from recycled cardboard. PMID:26744923

  10. Ring closing and opening reactions leading to aza-polycyclic aromatic compounds

    OpenAIRE

    Kethe, Anila; Li, Ang; Klumpp, Douglas A.

    2012-01-01

    A series of functionalized aza-polycyclic aromatic compounds were prepared by a superacid-promoted ring closing and opening reaction cascade. A reaction mechanism is proposed, which involves reactive dicationic intermediates. A key step in the conversions involves ipso protonation of an aryl group and elimination of an alkyl phenyl group.

  11. Improvement of mineral oil saturated and aromatic hydrocarbons determination in edible oil by liquid-liquid-gas chromatography with dual detection.

    Science.gov (United States)

    Zoccali, Mariosimone; Barp, Laura; Beccaria, Marco; Sciarrone, Danilo; Purcaro, Giorgia; Mondello, Luigi

    2016-02-01

    Mineral oils, which are mainly composed of saturated hydrocarbons and aromatic hydrocarbons, are widespread food contaminants. Liquid chromatography coupled to gas chromatography with flame ionization detection represents the method of choice to determine these two families. However, despite the high selectivity of this technique, the presence of olefins (particularly squalene and its isomers) in some samples as in olive oils, does not allow the correct quantification of the mineral oil aromatic hydrocarbons fraction, requiring additional off-line tools to eliminate them. In the present research, a novel on-line liquid chromatography coupled to gas chromatography method is described for the determination of hydrocarbon contamination in edible oils. Two different liquid chromatography columns, namely a silica one (to retain the bulk of the matrix) and a silver-ion one (which better retains the olefins), were coupled in series to obtain the mineral oil aromatic hydrocarbons hump free of interfering peaks. Furthermore, the use of a simultaneous dual detection, flame ionization detector and triple quadrupole mass spectrometer allowed us not only to quantify the mineral oil contamination, but also to evaluate the presence of specific markers (i.e. hopanes) to confirm the petrogenic origin of the contamination. PMID:26614690

  12. Analysis of Maisotsenko open gas turbine power cycle with a detailed air saturator model

    International Nuclear Information System (INIS)

    Highlights: • Developed an accurate air saturator model. • Performed sensitivity analysis for Maisotsenko gas turbine cycle (MGTC). • Performed comparative analysis for MGTC and simple gas turbine with reheat (SGTR) and humid air turbine (HAT). • MGTC has higher efficiency and specific work output with at high compressor pressure ratio. • Optimum air saturator water mass flow rate is calculated. - Abstract: With ever increasing cost of fossil fuels and natural gas, the improvement in gas turbine power cycle efficiency is needed due to the tremendous savings in fuel consumption. Water/steam injection is considered as one of the most popular power augmentation techniques because of its significant impact on the gas turbine performance. One of the recently suggested evaporative gas turbine cycles is the Maisotsenko open cycle for gas turbine power generation. In this paper, detailed thermodynamic analysis of this cycle is investigated with a thorough air saturator model. A comparative analysis is carried out to signify the advantages and disadvantages of Maisotsenko gas turbine cycle (MGTC) as compared with humid air gas turbine cycles. MGTC performance is evaluated based on a simple recuperated gas turbine cycle. In addition, sensitivity analysis is performed to investigate the effect of different operating parameters on the overall cycle performance. Finally, integrating an air saturator instead of a conventional heat exchanger in recuperated gas turbine cycles enhances the power plant performance such that an efficiency enhancement of 7% points and net specific work output augmentation of 44.4% are obtained

  13. Geochemical implications of trace elements and sulfur in the saturate, aromatic and resin fractions of crude oil from the Mara and Mara Oeste fields, Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Liliana Lopez; Salvador Lo Monaco [Universidad Central de Venezuela, Caracas (Venezuela). Facultad de Ciencias, Instituto de Ciencias de la Tierra

    2004-02-01

    Ten trace elements (Cr, Zn, Fe, Mn, Cu, Co, Ni, Mo, V and Sr) and sulfur were determined in the saturate, aromatic and resin fractions of 15 crude oils from Mara (DM) and Mara Oeste (DMO) fields of the Maracaibo Basin, Venezuela. The oils studied are classified as unaltered or altered by biodegradation. In the altered oil, the depletion of n-alkanes, the absence of isoprenoids and the presence of steranes and hopanes unaltered by biodegradation are indicative of moderate biodegradation. The elements Zn, Fe, Mn, Cu, Ni, and Sr were detected in the saturated hydrocarbon fraction; Cr and V were detected in the aromatic fraction in addition to the above elements; whereas the elements detected for the resin fraction were Cr, Zn, Fe, Cu, Ni, Mo, V, and Sr. Co was not detected in any fractions of the oils analyzed. Sulfur was found in all fractions of the oils studied. It was proposed that Fe, Zn, Sr, and Mn could have entered the oil during migration or Fe, Zn and Mn as pollutants during oil extraction. Cr and Cu may be of biological origin and Mo could be incorporated into the reservoir through bacteria. Only S, V, and Ni in the resin fractions can be used as indicators of the origin and correlation of Mara and Mara Oeste oils. Based on the results obtained in this work, it can be established that the V/(V+Ni) ratio in the resin fraction can be used as a correlation parameter, for these oils. 30 refs., 7 figs., 8 tabs.

  14. Geochemical characterization of lower Toarcian source rocks from NW Germany: interpretation of aromatic and saturated hydrocarbons in relation to depositional environment and maturation effects

    Energy Technology Data Exchange (ETDEWEB)

    Radke, M.; Schaefer, R.G. [Institut fuer Erdol und Organische Geochemie, Juelich (Germany); Vriend, S.P. [University of Utrecht (Netherlands). Institute of Earth Sciences

    2001-07-01

    The characterization of crude oils in terms of source rock facies and depositional environment, as well as their maturity and alteration stage, is a crucial element in exploration studies. The present contribution has implications for oil-oil and oil-source rock correlations. In the past, numerous parameters have been used for this purpose most of which are based on the analysis of saturated and aromatic hydrocarbons (including sulphur aromatics) and also on stable isotope signatures and elemental compositions. Recently, molecular indicators based on dibenzothiophene (DBT), phenanthrene (PHE) and their methyl derivatives methyldlbenzothiophene (MDBT) an methylphenanthrene, as well as pristane (PRI) and phytane (PHY), have also been proposed (Hughes et al, 1995). These studies have attempted to infer a crude oil's source rock facies and lithology, and to classify the source rock's depositional environment. In the present study, the above compounds have been quantified by solvent extraction, liquid chromatography and capillary gas chromatography in 98 core samples of the Lower Toarcian Posidonia Shale Formation, a source rock in NW Germany. Most samples cored between depths of 7m and 70 m, came from the Hils Half-Graben in the Lower Saxony Basin. With a few exceptions from on borehole, the samples were unweathered maris or calcareous shales. The rocks contained mainly marine organic matter (Type 1 kerogen), the thermal maturity of which ranged from early mature to postmature (corresponding to 0.48-1.44% mean vitrinite reflectance), therefore encompassing the range over which effective petroleum generation had occurred. We found that the influence of organic matter type and maturity on the molecular distributions of the above compounds were not obvious when interpreted in term of a DBT/PHE vs PRI/PHY diagram. However, Principal Component Analysis (PCA) of our data-set showed that alkylphenanthren concentrations are strongly controlled by maturity, while the

  15. Optimization of pressurized liquid extraction (PLE) for rapid determination of mineral oil saturated (MOSH) and aromatic hydrocarbons (MOAH) in cardboard and paper intended for food contact.

    Science.gov (United States)

    Moret, Sabrina; Sander, Maren; Purcaro, Giorgia; Scolaro, Marianna; Barp, Laura; Conte, Lanfranco S

    2013-10-15

    Packaging can represent a primary source of food contamination with mineral oil saturated hydrocarbons (MOSH) and aromatic hydrocarbons (MOAH), especially when recycled cardboard or mineral oil based printing inks are used. A pressurized liquid extraction (PLE) method, followed by on-line LC-GC analysis, has been optimized for rapid mineral oil determination in cardboard and paper samples. The proposed method involves extraction with hexane (2 cycles) at 60°C for 5 min, and allows for the processing of up to 6 samples in parallel with minimal sample manipulation and solvent consumption. It gave good repeatability (coefficient of variation lower than 5%) and practically quantitative extraction yield (less than 2% of the total contamination found in a third separate cycle). The method was applied to different cardboards and paper materials intended for food contact. Results obtained were similar to those obtained by applying classical solvent extraction with hexane/ethanol 1:1 (v/v) as described by Lorenzini et al. [20]. PMID:24054587

  16. Saturation mutagenesis of Bradyrhizobium sp. BTAi1 toluene 4-monooxygenase at alpha-subunit residues proline 101, proline 103, and histidine 214 for regiospecific oxidation of aromatics.

    Science.gov (United States)

    Yanık-Yıldırım, K Cansu; Vardar-Schara, Gönül

    2014-11-01

    A novel toluene monooxygenase (TMO) six-gene cluster from Bradyrhizobium sp. BTAi1 having an overall 35, 36, and 38 % protein similarity with toluene o-xylene monooxygenase (ToMO) of Pseudomonas sp. OX1, toluene 4-monooxygenase (T4MO) of Pseudomonas mendocina KR1, and toluene-para-monooxygenase (TpMO) of Ralstonia pickettii PKO1, respectively, was cloned and expressed in Escherichia coli TG1, and its potential activity was investigated for aromatic hydroxylation and trichloroethylene (TCE) degradation. The natural substrate toluene was hydroxylated to p-cresol, indicating that the new toluene monooxygenase (T4MO·BTAi1) acts as a para hydroxylating enzyme, similar to T4MO and TpMO. Some shifts in regiospecific hydroxylations were observed compared to the other wild-type TMOs. For example, wild-type T4MO·BTAi1 formed catechol (88 %) and hydroquinone (12 %) from phenol, whereas all the other wild-type TMOs were reported to form only catechol. Furthermore, it was discovered that TG1 cells expressing wild-type T4MO·BTAi1 mineralized TCE at a rate of 0.67 ± 0.10 nmol Cl(-)/h/mg protein. Saturation and site directed mutagenesis were used to generate eight variants of T4MO·BTAi1 at alpha-subunit positions P101, P103, and H214: P101T/P103A, P101S, P101N/P103T, P101V, P103T, P101V/P103T, H214G, and H214G/D278N; by testing the substrates phenol, nitrobenzene, and naphthalene, positions P101 and P103 were found to influence the regiospecific oxidation of aromatics. For example, compared to wild type, variant P103T produced four fold more m-nitrophenol from nitrobenzene as well as produced mainly resorcinol (60 %) from phenol whereas wild-type T4MO·BTAi1 did not. Similarly, variants P101T/P103A and P101S synthesized more 2-naphthol and 2.3-fold and 1.6-fold less 1-naphthol from naphthalene, respectively. PMID:25016343

  17. EPOXIDE RING OPENING AND RELATED REACTIVITIES OF CYCLOPENTAL POLYCYCLIC AROMATIC HYDROCARBONS: QUANTUM MECHANICAL STUDIES

    Science.gov (United States)

    For a series of cyclopenta-polynuclear aromatic hydrocarbons, epoxidated in the cyclopenta ring, semi-empirical AM1 calculations, and single point ab initio calculations using the 3-21g split valence basis set, have been performed for the each carbocation that might be formed by ...

  18. Matrix isolation Fourier transform infrared spectrometric detection in the open tubular column gas chromatography of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Hembree, D.M.; Garrison, A.A.; Crocombe, R.A.; Yokley, R.A.; Wehry, E.L.; Mamantov, G.

    1981-10-01

    A detailed description of a system for gas chromatographic (GC) detection of matrix isolation Fourier transform infrared (FTIR) spectrometry is presented. Substances eluting from a support-coated open tubular column are deposited directly on individual faces of a 12-sided movable gold-plated copper disk mounted within the cold head of a closed-cycle cryostat. The same gas is used as GC carrier and spectroscopic matrix gas. An optical interface, comprising beam condensing and rod optics, permits the modified cryostat head to be mounted in proximity to the sample chamber of an FTIR spectrometer. Applications of the technique to identification of polycyclic aromatic hydrocarbon constituents of coal-derived materials are demonstrated, and quantitative aspects of the procedure are considered.

  19. Effect of slow versus rapid rewarming on jugular bulb oxygen saturation in adult patients undergoing open heart surgery

    Directory of Open Access Journals (Sweden)

    Mohmaed Shaaban Ali

    2014-01-01

    Full Text Available Background: A debate has appeared in the recent literature about the optimum rewarming strategy (slow vs. rapid for the best brain function. This study was designed to compare the effect of slow versus rapid rewarming on jugular bulb oxygen saturation (SjO 2 in adult patients undergoing open heart surgery. Materials and Methods: A total of 80 patients undergoing valve and adult congenital heart surgery were randomly allocated equally to rapid rewarming group 0.5 (0.136°C/min and slow rewarming group 0.219 (0.055°C/min in jugular bulb sampling was taken before, during and after surgery. Surgery was done at cardiopulmonary bypass (CPB temperature of 28-30°C and rewarming was performed at the end of the surgical procedure. Results: CPB time, rewarming period were significantly longer in the slow rewarming group. Significant difference was observed in the number of the desaturated patients (SjO 2 ≤ 50% between the two groups; 14 (35% in rapid rewarming versus 6 (15% in the slow rewarming group; P = 0.035 by Fisher′s exact test. Conclusions: Slow rewarming could reduce the incidence of SjO 2 desaturation during rewarming in adult patients undergoing open heart surgery.

  20. Calculation of the thermodynamic properties at elevated temperatures and pressures of saturated and aromatic high molecular weight solid and liquid hydrocarbons in kerogen, bitumen, petroleum, and other organic matter of biogeochemical interest

    Energy Technology Data Exchange (ETDEWEB)

    Richard, L.; Helgeson, H.C. [Univ. of California, Berkeley, CA (United States). Dept. of Geology and Geophysics

    1998-12-01

    To supplement the relatively sparse set of calorimetric data available for the multitude of high molecular weight organic compounds of biogeochemical interest, group additivity algorithms have been developed to estimate heat capacity power function coefficients and the standard molal thermodynamic properties at 25 C and 1 bar of high molecular weight compounds in hydrocarbon source rocks and reservoirs, including crystalline and liquid isoprenoids, steroids, tricyclic diterpenoids, hopanoids, and polynuclear aromatic hydrocarbons. A total of ninety-six group contributions for each coefficient and property were generated from the thermodynamic properties of lower molecular weight reference species for which calorimetric data are available in the literature. These group contributions were then used to compute corresponding coefficients and properties for {approximately}360 representative solid and liquid high molecular weight compounds in kerogen, bitumen, and petroleum for which few or no experimental data are available. The coefficients and properties of these high molecular weight compounds are summarized in tables, together with those of the groups and reference species from which they were generated. The tabulated heat capacity power function coefficients and standard molal thermodynamic properties at 25 C and 1 bar include selected crystalline and liquid regular, irregular and highly branched isoprenoids, tricyclic diterpanes, 17{alpha}(H)- and 17{beta}(H)-hopanes, 5{alpha}(H),14{alpha}(H)-, 5{beta}(H),14{alpha}(H)-, 5{alpha}(H),14{beta}(H)-, and 5{beta}(H),14{beta}(H)-steranes, double ether- and ester-bonded n-alkanes, and various polynuclear aromatic hydrocarbons, including methylated biphenyls, naphthalenes, phenanthrenes, anthracenes, pyrenes, and chrysenes. However, corresponding coefficients and properties for many more saturated and unsaturated high molecular weight hydrocarbons can be estimated from the equations of state group additivity algorithms

  1. Calculation of the thermodynamic properties at elevated temperatures and pressures of saturated and aromatic high molecular weight solid and liquid hydrocarbons in kerogen, bitumen, petroleum, and other organic matter of biogeochemical interest

    Science.gov (United States)

    Richard, Laurent; Helgeson, Harold C.

    1998-12-01

    To supplement the relatively sparse set of calorimetric data available for the multitude of high molecular weight organic compounds of biogeochemical interest, group additivity algorithms have been developed to estimate heat capacity power function coefficients and the standard molal thermodynamic properties at 25°C and 1 bar of high molecular weight compounds in hydrocarbon source rocks and reservoirs, including crystalline and liquid isoprenoids, steroids, tricyclic diterpenoids, hopanoids, and polynuclear aromatic hydrocarbons. A total of ninety-six group contributions for each coefficient and property were generated from the thermodynamic properties of lower molecular weight reference species for which calorimetric data are available in the literature. These group contributions were then used to compute corresponding coefficients and properties for ˜360 representative solid and liquid high molecular weight compounds in kerogen, bitumen, and petroleum for which few or no experimental data are available. The coefficients and properties of these high molecular weight compounds are summarized in tables, together with those of the groups and reference species from which they were generated. The tabulated heat capacity power function coefficients and standard molal thermodynamic properties at 25°C and 1 bar include selected crystalline and liquid regular, irregular and highly branched isoprenoids, tricyclic diterpanes, 17α(H)- and 17β(H)-hopanes, 5α(H),14α(H)-, 5β(H),14α(H)-, 5α(H),14β(H)-, and 5β(H),14β(H)-steranes, double ether- and ester-bonded n-alkanes, and various polynuclear aromatic hydrocarbons, including methylated biphenyls, naphthalenes, phenanthrenes, anthracenes, pyrenes, and chrysenes. However, corresponding coefficients and properties for many more saturated and unsaturated high molecular weight hydrocarbons can be estimated from the equations of state group additivity algorithms. Calculations of this kind permit comprehensive

  2. Use of the modified three-point Dixon technique in obtaining T1-weighted contrast-enhanced fat-saturated images on an open magnet

    Energy Technology Data Exchange (ETDEWEB)

    Huegli, Rolf W. [University of California, Osteoporosis and Arthritis Research Group, Department of Radiology, San Francisco, CA (United States); Kantonsspital Basel, Universitaetskliniken, Departement Medizinische Radiologie, Basel (Switzerland); Tirman, Phillip F.J. [Marin Magnetic Imaging, National Orthopaedic Imaging Associates, Greenbrae, CA (United States); Bonel, Harald M.; Zaim, Souhil; Grigorian, Mikayel; Genant, Harry K. [University of California, Osteoporosis and Arthritis Research Group, Department of Radiology, San Francisco, CA (United States); Staedele, Harald [Kantonsspital Basel, Universitaetskliniken, Departement Medizinische Radiologie, Basel (Switzerland)

    2004-10-01

    The purpose of this study was to investigate the modified three-point Dixon technique as a method for obtaining fat-saturated T1-weighted sequences before and after intravenous gadolinium administration using an open MR imaging scanner. A preliminary experiment using an oil/gadolinium phantom was performed on a 0.35-T open magnet and an advanced 1.5-T unit. Fat saturation was achieved at 1.5 T using a frequency selective presaturation technique and a modified three-point Dixon technique on the low-field scanner. The modified three-point Dixon sequence was then evaluated in ten patients undergoing MRI examinations of the spine with gadolinium enhancement to determine image characteristics and diagnostic potential. The phantom study demonstrated a homogenous suppression of signal from oil and a good distinction between fat and a gadolinium chelate on the 0.35-T unit comparable to that on the 1.5-T scanner. By applying the modified three-point Dixon technique on the open-magnet, the distinction between fat and gadolinium dimeglumine was rated as very good in 139 and good in 17 axial slices in a total of 156 images. No image was rated as difficult or not possible. Motion artifacts that hampered the reading were detected in the lower cervical spine due to respiratory movement in four (3% of all) images. The modified three-point Dixon technique provides the combination of gadolinium enhancement with fat saturation on an open magnet. Early clinical applications appear promising. (orig.)

  3. Use of the modified three-point Dixon technique in obtaining T1-weighted contrast-enhanced fat-saturated images on an open magnet

    International Nuclear Information System (INIS)

    The purpose of this study was to investigate the modified three-point Dixon technique as a method for obtaining fat-saturated T1-weighted sequences before and after intravenous gadolinium administration using an open MR imaging scanner. A preliminary experiment using an oil/gadolinium phantom was performed on a 0.35-T open magnet and an advanced 1.5-T unit. Fat saturation was achieved at 1.5 T using a frequency selective presaturation technique and a modified three-point Dixon technique on the low-field scanner. The modified three-point Dixon sequence was then evaluated in ten patients undergoing MRI examinations of the spine with gadolinium enhancement to determine image characteristics and diagnostic potential. The phantom study demonstrated a homogenous suppression of signal from oil and a good distinction between fat and a gadolinium chelate on the 0.35-T unit comparable to that on the 1.5-T scanner. By applying the modified three-point Dixon technique on the open-magnet, the distinction between fat and gadolinium dimeglumine was rated as very good in 139 and good in 17 axial slices in a total of 156 images. No image was rated as difficult or not possible. Motion artifacts that hampered the reading were detected in the lower cervical spine due to respiratory movement in four (3% of all) images. The modified three-point Dixon technique provides the combination of gadolinium enhancement with fat saturation on an open magnet. Early clinical applications appear promising. (orig.)

  4. Scientific Opinion on the safety and efficacy of aliphatic, alicyclic and aromatic saturated and unsaturated tertiary alcohols and esters with esters containing tertiary alcohols ethers (chemical group 6 when used as flavourings for all animal species

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2012-11-01

    Full Text Available Chemical group 6 consists of aliphatic, alicyclic and aromatic saturated and unsaturated tertiary alcohols and esters with esters containing tertiary alcohols ethers, of which 13 are currently authorised for use as flavours in food. The high use level proposed by the applicant for linalool (25 mg/kg complete feed is safe for salmonids, veal calves, cattle for fattening and pets (excluding cats without a margin of safety with the exception of dogs (SF = 1.4. The safe use level for pigs and dairy cows is 20, for piglets 12 and for poultry 10 mg/kg complete feed. The high use level of 5 mg/kg complete feed for linalyl acetate, linalyl butyrate, linalyl formate, linalyl propionate, linalyl isobutyrate, terpineol, α-terpineol and terpineol acetate and 4-terpinenol is safe for all species with a margin of safety of 1.2 to 12. For nerolidol, 2-methyl-1-phenylpropan-2-ol and 2-(4-methylphenylpropan-2-ol, the maximum safe concentration is 1 mg/kg complete feed for pigs and poultry and 1.5 mg/kg complete feed for all other species. The absence of a margin of safety would not allow the simultaneous administration in feed and water for drinking of the following compounds: linalool, nerolidol, 2-methyl-1-phenylpropan-2-ol and 2-(4methylphenylpropan-2-ol. No safety concern would arise for the consumer from the use of compounds belonging to CG 6 up to the highest safe level in feedingstuffs for all animal species. All compounds should be considered as irritants to skin, eyes and respiratory tract, and as skin sensitisers. All compounds of CG 6 are predicted to be safe to the soil compartment when used at levels safe to the target species. Using predictions based on chemical structure, 2-methyl-1-phenylpropan-2-ol and 2-(4-methylphenylpropan-2-ol were estimated to be safe to aquatic compartments. In the absence of experimental data, safety to aquatic compartments could not be established for linalyl butyrate, linalyl isobutyrate, terpineol acetate, 4

  5. Fiscal 1996 international research cooperation project. Feasibility study of finding out the seeds of international joint research (technology for effective use of saturated hydrocarbon, technology for reducing excess of aromatic hydrocarbon, high-grade treatment technology of petroleum coke); 1996 nendo kokusai kenkyu kyoryoku jigyo. Kokusai kyodo kenkyu seeds hakkutsu no tame no FS chosa (howa tanka suiso no yuko riyo gijutsu, hokozoku tanka suiso no yojo taisaku gijutsu, sekiyu cokes no kodo shori gijutsu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    This project is aimed at internationally cooperating in the R and D of industrial technology and improving industrial technology of Japan. For it, the following three technologies were investigated: (1) technology for effective use of saturated hydrocarbon, (2) technology for reducing excess of aromatic hydrocarbon, (3) high-grade treatment technology of petroleum coke. In (1), surveys were conducted of technologies of effective use of natural gas and effective use of C4 saturated hydrocarbon. Surveyed were a method for producing synthesis gas from natural gas, a technology to liquefy natural gas into fuel following the synthesis gas production process, a technology to liquefy natural gas into fuel without the synthesis gas production process, and the trend of effective use of C4 saturated hydrocarbon. In (2), surveys were made of process to reduce production of aromatic hydrocarbon as much as possible, process to effectively separate aromatic hydrocarbon, and process to convert excess aromatic hydrocarbon into polymer, etc. In (3), surveys were conducted on petroleum coke and pitch in terms of production methods, the supply/demand situation, property characteristics, usability to new fields, etc. 170 refs., 114 figs., 65 tabs.

  6. X-ray computed-tomography imaging of gas migration in water-saturated sediments: From capillary invasion to conduit opening

    Science.gov (United States)

    Choi, Jeong-Hoon; Seol, Yongkoo; Boswell, Ray; Juanes, Ruben

    2011-09-01

    The strong coupling between multiphase flow and sediment mechanics determines the spatial distribution and migration dynamics of gas percolating through liquid-filled soft granular media. Here, we investigate, by means of controlled experiments and computed tomography (CT) imaging, the preferential mode of gas migration in three-dimensional samples of water-saturated silica-sand and silica-silt sediments. Our experimental system allowed us to independently control radial and axial confining stresses and pore pressure while performing continuous x-ray CT scanning. The CT image analysis of the three-dimensional gas migration provides the first experimental confirmation that capillary invasion preferentially occurs in coarse-grained sediments whereas grain displacement and conduit openings are dominant in fine-grained sediments. Our findings allow us to rationalize prior field observations and pore-scale modeling results, and provide critical experimental evidence to explain the means by which conduits for the transit of methane gas may be established through the gas hydrate stability zone in oceanic sediments, and cause large episodic releases of carbon into the deep ocean.

  7. Differences in Ambient Polycyclic Aromatic Hydrocarbon Concentrations between Streets and Alleys in New York City: Open Space vs. Semi-Closed Space

    Directory of Open Access Journals (Sweden)

    Stephanie Lovinsky-Desir

    2016-01-01

    Full Text Available Background: Outdoor ambient polycyclic aromatic hydrocarbon (PAH concentrations are variable throughout an urban environment. However, little is known about how variation in semivolatile and nonvolatile PAHs related to the built environment (open space vs. semi-closed space contributes to differences in concentrations. Methods: We simultaneously collected 14, two-week samples of PAHs from the outside of windows facing the front (adjacent to the street open side of a New York City apartment building and the alley, semi-closed side of the same apartment unit between 2007 and 2012. We also analyzed samples of PAHs measured from 35 homes across Northern Manhattan and the Bronx, 17 from street facing windows with a median floor level of 4 (range 2–26 and 18 from alley-facing windows with a median floor level of 4 (range 1–15. Results: Levels of nonvolatile ambient PAHs were significantly higher when measured from a window adjacent to a street (an open space, compared to a window 30 feet away, adjacent to an alley (a semi-closed space (street geometric mean (GM 1.32 ng/m3, arithmetic mean ± standard deviation (AM ± SD 1.61 ± 1.04 ng/m3; alley GM 1.10 ng/m3, AM ± SD 1.37 ± 0.94 ng/m3. In the neighborhood-wide comparison, nonvolatile PAHs were also significantly higher when measured adjacent to streets compared with adjacent to alley sides of apartment buildings (street GM 1.10 ng/m3, AM ± SD 1.46 ± 1.24 ng/m3; alley GM 0.61 ng/m3, AM ± SD 0.81 ± 0.80 ng/m3, but not semivolatile PAHs. Conclusions: Ambient PAHs, nonvolatile PAHs in particular, are significantly higher when measured from a window adjacent to a street compared to a window adjacent to an alley, despite both locations being relatively close to street traffic. This study highlights small-scale spatial variations in ambient PAH concentrations that may be related to the built environment (open space vs. semi-closed space from which the samples are measured, as well as the relative

  8. Aromatic graphene

    Science.gov (United States)

    Das, D. K.; Sahoo, S.

    2016-04-01

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

  9. Saturated fat (image)

    Science.gov (United States)

    ... saturated fats. Vegetable sources of saturated fat include coconut and palm oils. When looking at a food ... saturated fats. Vegetable sources of saturated fat include coconut and palm oils. When looking at a food ...

  10. Advances towards aromatic oligoamide foldamers

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  11. Fiscal 1997 report on the results of the international research cooperation project for a feasibility survey for finding out seeds of the international joint research. Effective use technology of saturated hydrocarbon (technology against the surplus aromatic hydrocarbon/technology of high grade treatment of petroleum coke); 1997 nendo kokusai kenkyu kyoryoku jigyo (kokusai kyodo kenkyu seeds hakkutsu no tame no FS chosa). Howa tanka suiso no yuko riyo gijutsu / hokozoku tanka suiso no yojo taisaku gijutsu / sekiyu cokes no kodo shori gijutsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    For the purpose of the effective international research cooperation, the paper surveyed in fiscal 1997 the effective use technology of saturated hydrocarbon, technology against the surplus aromatic hydrocarbon and technology of high grade treatment of petroleum coke. In the survey of the effective use technology of saturated hydrocarbon, trends of FT synthesis technology and DME synthesis technology were studied as trends of technology to produce synthetic gas, and a project was proposed for technical development of using natural gas as liquid fuel in Japan. In the survey of technology against the surplus aromatic hydrocarbon, studied were the benzene law regulation and the supply/demand trend of aromatic hydrocarbon, process to reduce production of aromatic hydrocarbon as much as possible, process to reduce aromatics of the produced petroleum products, and process to effectively use aromatic hydrocarbon as chemical raw material. In the survey of high grade treatment of petroleum coke, studied were a possibility of using HS petroleum coke in the DIOS method, iron bath gasification, and copper bath gasification technology. 108 refs., 146 figs., 103 tabs.

  12. Volatilisation of aromatic hydrocarbons from soil

    DEFF Research Database (Denmark)

    Lindhardt, B.; Christensen, T.H.

    1996-01-01

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

  13. Theory of graphene saturable absorption

    CERN Document Server

    Marini, A; de Abajo, F J Garcia

    2016-01-01

    Saturable absorption is a non-perturbative nonlinear optical phenomenon that plays a pivotal role in the generation of ultrafast light pulses. Here we show that this effect emerges in graphene at unprecedentedly low light intensities, thus opening avenues to new nonlinear physics and applications in optical technology. Specifically, we theoretically investigate saturable absorption in extended graphene by developing a non-perturbative single-particle approach, describing conduction-electron dynamics in the atomically-thin material using the two-dimensional Dirac equation for massless Dirac fermions, which is recast in the form of generalized Bloch equations. By solving the electron dynamics non-perturbatively, we account for both interband and intraband contributions to the intensity-dependent saturated conductivity and conclude that the former dominates regardless of the intrinsic doping state of the material. The results are in excellent agreement with atomistic quantum-mechanical simulations including high...

  14. Saturated Switching Systems

    CERN Document Server

    Benzaouia, Abdellah

    2012-01-01

    Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

  15. Gluon saturation in a saturated environment

    Science.gov (United States)

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan

    2011-07-01

    A bootstrap equation for self-quenched gluon shadowing leads to a reduced magnitude of broadening for partons propagating through a nucleus. Saturation of small-x gluons in a nucleus, which has the form of transverse momentum broadening of projectile gluons in pA collisions in the nuclear rest frame, leads to a modification of the parton distribution functions in the beam compared with pp collisions. In nucleus-nucleus collisions all participating nucleons acquire enhanced gluon density at small x, which boosts further the saturation scale. Solution of the reciprocity equations for central collisions of two heavy nuclei demonstrate a significant, up to several times, enhancement of QsA2, in AA compared with pA collisions.

  16. Gluon saturation in a saturated environment

    International Nuclear Information System (INIS)

    A bootstrap equation for self-quenched gluon shadowing leads to a reduced magnitude of broadening for partons propagating through a nucleus. Saturation of small-x gluons in a nucleus, which has the form of transverse momentum broadening of projectile gluons in pA collisions in the nuclear rest frame, leads to a modification of the parton distribution functions in the beam compared with pp collisions. In nucleus-nucleus collisions all participating nucleons acquire enhanced gluon density at small x, which boosts further the saturation scale. Solution of the reciprocity equations for central collisions of two heavy nuclei demonstrate a significant, up to several times, enhancement of QsA2, in AA compared with pA collisions.

  17. Adsorption of Oil onto API-X100 Pipeline Steel in CO2-Saturated Solutions

    Science.gov (United States)

    Eliyan, Faysal Fayez; Alfantazi, Akram

    2013-12-01

    This research explores the validity of Langmuir adsorption theorem in analyzing the natural corrosion inhibition by an aromatic C10H12 compound, in a hydrocarbon fuel, in 1-bar CO2-saturated solutions. The adsorption isotherms were constructed from the efficiencies of inhibition, by 10, 20, and 30 vol pct of the fuel, of the corrosion rates calculated from potentiodynamic polarization measurements, in 2 NaCl g/L solutions at 293 K, 323 K, and 353 K (20 °C, 50 °C, and 80 °C). The corrosion rates increased with temperature, and the hydrocarbon fuel, seemingly showing cathodic-inhibition characteristics, acted less efficiently accordingly; two main results the potentiodynamic polarization, electrochemical impedance spectroscopy and open-circuit measurements, demonstrated agreement on with each other.

  18. Saturated Domino Coverings

    CERN Document Server

    Buchanan, Andrew; Ryba, Alex

    2011-01-01

    A domino covering of a board is saturated if no domino is redundant. We introduce the concept of a fragment tiling and show that a minimal fragment tiling always corresponds to a maximal saturated domino covering. The size of a minimal fragment tiling is the domination number of the board. We define a class of regular boards and show that for these boards the domination number gives the size of a minimal X-pentomino covering. Natural sequences that count maximal saturated domino coverings of square and rectangular boards are obtained. These include the new sequences A193764, A193765, A193766, A193767, and A193768 of OEIS.

  19. Global aromatics supply. Today and tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Bender, M. [BASF SE, Ludwigshafen (Germany)

    2013-11-01

    Aromatics are the essential building blocks for some of the largest petrochemical products in today's use. To the vast majority they are consumed to produce intermediates for polymer products and, hence, contribute to our modern lifestyle. Their growth rates are expected to be in line with GDP growth in future. This contrasts the significantly lower growth rates of the primary sources for aromatics - fuel processing and steam cracking of naphtha fractions. A supply gap can be expected to open up in future for which creative solutions will be required. (orig.)

  20. Superconductivity in aromatic hydrocarbons

    International Nuclear Information System (INIS)

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

  1. Crack arrest saturation model under combined electrical and mechanical loadings

    OpenAIRE

    R.R. Bhargava; A. Setia

    2009-01-01

    Purpose: The investigation aims at proposing a model for cracked piezoelectric strip which is capable to arrest the crack.Design/methodology/approach: Under the combined effect of electrical and mechanical loadings applied at the edges of the strip, the developed saturation zone is produced at each tip of the crack. To arrest further opening of the crack, the rims of the developed saturation zones are subjected to in-plane cohesive, normal uniform constant saturation point electrical displace...

  2. Biodegradation of diesel/biodiesel blends in saturated sand microcosms

    DEFF Research Database (Denmark)

    Lisiecki, Piotr; Chrzanowski, Łukasz; Szulc, Alicja;

    2014-01-01

    The aim of the study was to evaluate the biodegradation extent of both aromatic and aliphatic hydrocarbon fractions in saturated sandy microcosm spiked with diesel/biodiesel blends (D, B10, B20, B30, B40, B50, B60, B70, B80, B90 and B100, where D is commercial petroleum diesel fuel and B is...... commercial biodiesel blend) augmented with a bacterial consortium of petroleum degraders. The biodegradation kinetics for blends were evaluated based on measuring the amount of emitted CO2 after 578 days. Subsequently, the residual aromatic and aliphatic fractions were separated and determined by employing...... GC-FID and GC _ GC–TOF-MS. Additionally, the influence of biodiesel-amendment on the community dynamics was assessed based on the results of real-time PCR analyzes. Our results suggest that the biodegradation extents of both aliphatic and aromatic hydrocarbon were uninfluenced by the addition of...

  3. Superconductivity in aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-15

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

  4. Infinite saturated orders

    CERN Document Server

    Dzhafarov, Damir D

    2010-01-01

    We generalize the notion of saturated order to infinite partial orders and give both a set-theoretic and an algebraic characterization of such orders. We then study the proof theoretic strength of the equivalence of these characterizations in the context of reverse mathematics, showing that depending on one's choice of definitions it is either provable in $\\mathsf{RCA}_0$ or equivalent to $\\mathsf{ACA}_0$.

  5. Capillary saturation and desaturation.

    Science.gov (United States)

    Hilfer, R; Armstrong, R T; Berg, S; Georgiadis, A; Ott, H

    2015-12-01

    Capillary desaturation experiments produce disconnected (trapped) ganglia of mesoscopic sizes intermediate between pore size and system size. Experimental evidence for interactions between these mesoscale clusters during desaturation is analyzed and discussed within the established microscopic and macroscopic laws of Newton, Young-Laplace, and Darcy. A theoretical expression for capillary number correlations is introduced that seems to have remained unnoticed. It expresses capillary desaturation curves in terms of stationary capillary pressures and relative permeabilities. The theoretical expression shows that the plateau saturation in capillary desaturation curves may in general differ from the residual nonwetting saturation defined through the saturation limit of the main hysteresis loop. Hysteresis effects as well as the difference between wetting and nonwetting fluids are introduced into the analysis of capillary desaturation experiments. The article examines experiments with different desaturation protocols and discusses the existence of a mesoscopic length scale intermediate between pore scale and sample scale. The theoretical expression is derived entirely within the existing traditional theory of two-phase flow in porous media and compared to a recent experiment. PMID:26764820

  6. Capillary saturation and desaturation

    Science.gov (United States)

    Hilfer, R.; Armstrong, R. T.; Berg, S.; Georgiadis, A.; Ott, H.

    2015-12-01

    Capillary desaturation experiments produce disconnected (trapped) ganglia of mesoscopic sizes intermediate between pore size and system size. Experimental evidence for interactions between these mesoscale clusters during desaturation is analyzed and discussed within the established microscopic and macroscopic laws of Newton, Young-Laplace, and Darcy. A theoretical expression for capillary number correlations is introduced that seems to have remained unnoticed. It expresses capillary desaturation curves in terms of stationary capillary pressures and relative permeabilities. The theoretical expression shows that the plateau saturation in capillary desaturation curves may in general differ from the residual nonwetting saturation defined through the saturation limit of the main hysteresis loop. Hysteresis effects as well as the difference between wetting and nonwetting fluids are introduced into the analysis of capillary desaturation experiments. The article examines experiments with different desaturation protocols and discusses the existence of a mesoscopic length scale intermediate between pore scale and sample scale. The theoretical expression is derived entirely within the existing traditional theory of two-phase flow in porous media and compared to a recent experiment.

  7. PROTONATED POLYCYCLIC AROMATIC HYDROCARBONS REVISITED

    International Nuclear Information System (INIS)

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

  8. Investigating coronal saturation and super-saturation in fast-rotating M-dwarf stars

    OpenAIRE

    Jeffries, R. D.; Jackson, R J; Briggs, K. R.; Evans, P A; Pye, J. P.

    2010-01-01

    At fast rotation rates the coronal activity of G- and K-type stars has been observed to "saturate" and then decline again at even faster rotation rates -- a phenomenon dubbed "super-saturation". In this paper we investigate coronal activity in fast-rotating M-dwarfs using deep XMM-Newton observations of 97 low-mass stars of known rotation period in the young open cluster NGC 2547, and combine these with published X-ray surveys of low-mass field and cluster stars of known rotation period. Like...

  9. Saturated Zone Colloid Transport

    International Nuclear Information System (INIS)

    This scientific analysis provides retardation factors for colloids transporting in the saturated zone (SZ) and the unsaturated zone (UZ). These retardation factors represent the reversible chemical and physical filtration of colloids in the SZ. The value of the colloid retardation factor, Rcol is dependent on several factors, such as colloid size, colloid type, and geochemical conditions (e.g., pH, Eh, and ionic strength). These factors are folded into the distributions of Rcol that have been developed from field and experimental data collected under varying geochemical conditions with different colloid types and sizes. Attachment rate constants, katt, and detachment rate constants, kdet, of colloids to the fracture surface have been measured for the fractured volcanics, and separate Rcol uncertainty distributions have been developed for attachment and detachment to clastic material and mineral grains in the alluvium. Radionuclides such as plutonium and americium sorb mostly (90 to 99 percent) irreversibly to colloids (BSC 2004 [DIRS 170025], Section 6.3.3.2). The colloid retardation factors developed in this analysis are needed to simulate the transport of radionuclides that are irreversibly sorbed onto colloids; this transport is discussed in the model report ''Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]). Although it is not exclusive to any particular radionuclide release scenario, this scientific analysis especially addresses those scenarios pertaining to evidence from waste-degradation experiments, which indicate that plutonium and americium may be irreversibly attached to colloids for the time scales of interest. A section of this report will also discuss the validity of using microspheres as analogs to colloids in some of the lab and field experiments used to obtain the colloid retardation factors. In addition, a small fraction of colloids travels with the groundwater without any significant retardation. Radionuclides irreversibly sorbed

  10. PROGRESS IN CATALYST AND PROCESS DEVELOPMENT FOR LOW SULFUR AND LOW AROMATICS DIESEL PRODUCTION

    Institute of Scientific and Technical Information of China (English)

    ZHOUYong; HANChong-ren

    2003-01-01

    The article includes three parts:①The development and performance of FH-DS catalyst for deep and ultra -deep distillate HDS;②The single stage HDS/HDA hydrotreating process for the production of low sulfur and low aromatics diesels from straight run and coker AGO by using highly active base metal catalyst at moderate pressure;③A two-stage aromatics saturation system utilizing noble metal catalyst in the second stage developed for production of low sulfur and low aromatics diesel from LCO.FDA catalyst developed by FRIPP has high activity for aromatics saturation together with high tolerance for sulfur and nitrogen in the feed.The process is effective in reducing density and increasing cetane number.

  11. Estrogenic Activity of Mineral Oil Aromatic Hydrocarbons Used in Printing Inks

    OpenAIRE

    Tarnow, Patrick; Hutzler, Christoph; Grabiger, Stefan; Schön, Karsten; Tralau, Tewes; Luch, Andreas

    2016-01-01

    The majority of printing inks are based on mineral oils (MOs) which contain complex mixtures of saturated and aromatic hydrocarbons. Consumer exposure to these oils occurs either through direct skin contacts or, more frequently, as a result of MO migration into the contents of food packaging that was made from recycled newspaper. Despite this ubiquitous and frequent exposure little is known about the potential toxicological effects, particularly with regard to the aromatic MO fractions. From ...

  12. Saturated Zone Colloid Transport

    Energy Technology Data Exchange (ETDEWEB)

    H. S. Viswanathan

    2004-10-07

    This scientific analysis provides retardation factors for colloids transporting in the saturated zone (SZ) and the unsaturated zone (UZ). These retardation factors represent the reversible chemical and physical filtration of colloids in the SZ. The value of the colloid retardation factor, R{sub col} is dependent on several factors, such as colloid size, colloid type, and geochemical conditions (e.g., pH, Eh, and ionic strength). These factors are folded into the distributions of R{sub col} that have been developed from field and experimental data collected under varying geochemical conditions with different colloid types and sizes. Attachment rate constants, k{sub att}, and detachment rate constants, k{sub det}, of colloids to the fracture surface have been measured for the fractured volcanics, and separate R{sub col} uncertainty distributions have been developed for attachment and detachment to clastic material and mineral grains in the alluvium. Radionuclides such as plutonium and americium sorb mostly (90 to 99 percent) irreversibly to colloids (BSC 2004 [DIRS 170025], Section 6.3.3.2). The colloid retardation factors developed in this analysis are needed to simulate the transport of radionuclides that are irreversibly sorbed onto colloids; this transport is discussed in the model report ''Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]). Although it is not exclusive to any particular radionuclide release scenario, this scientific analysis especially addresses those scenarios pertaining to evidence from waste-degradation experiments, which indicate that plutonium and americium may be irreversibly attached to colloids for the time scales of interest. A section of this report will also discuss the validity of using microspheres as analogs to colloids in some of the lab and field experiments used to obtain the colloid retardation factors. In addition, a small fraction of colloids travels with the groundwater without any significant

  13. Aliphatic and aromatic hydrocarbons in Candiota coal samples: novel series of bicyclic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, A.C.M.L.; Loureiro, M.R.B.; Cardoso, J.N. [Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil). Inst. de Quimica

    1999-07-01

    Gas chromatography - mass spectrometry was used to analyse aliphatic and aromatic fractions obtained from nine samples taken from two different seams of five boreholes in the Candiota coalfield (Lower Permian). The occurrence of certain tetracyclic diterpenoids among the aliphatic hydrocarbons, and the tricyclic diterpenoids simonellite and retene in the aromatic hydrocarbon concentrates, suggest an important input from conifers to the sedimentary biomass. This may explain the origin of a novel series of saturated and aromatic bicyclic compounds detected in the extracts which may be structurally related to the same precursor, possibly a conifer resin-derived tricyclic diterpenoid.

  14. Polyimidazoles via aromatic nucleophilic displacement

    Science.gov (United States)

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

    1992-01-01

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

  15. Brine Distribution after Vacuum Saturation

    DEFF Research Database (Denmark)

    Hedegaard, Kathrine; Andersen, Bertel Lohmann

    1999-01-01

    Experiments with the vacuum saturation method for brine in plugs of chalk showed that a homogeneous distribution of brine cannot be ensured at saturations below 20% volume. Instead of a homogeneous volume distribution the brine becomes concentrated close to the surfaces of the plugs......Experiments with the vacuum saturation method for brine in plugs of chalk showed that a homogeneous distribution of brine cannot be ensured at saturations below 20% volume. Instead of a homogeneous volume distribution the brine becomes concentrated close to the surfaces of the plugs...

  16. Aromatic molecules as spintronic devices

    International Nuclear Information System (INIS)

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

  17. Investigating coronal saturation and super-saturation in fast-rotating M-dwarf stars

    CERN Document Server

    Jeffries, R D; Briggs, K R; Evans, P A; Pye, J P

    2010-01-01

    At fast rotation rates the coronal activity of G- and K-type stars has been observed to "saturate" and then decline again at even faster rotation rates -- a phenomenon dubbed "super-saturation". In this paper we investigate coronal activity in fast-rotating M-dwarfs using deep XMM-Newton observations of 97 low-mass stars of known rotation period in the young open cluster NGC 2547, and combine these with published X-ray surveys of low-mass field and cluster stars of known rotation period. Like G- and K-dwarfs, we find that M-dwarfs exhibit increasing coronal activity with decreasing Rossby number N_R, the ratio of period to convective turnover time, and that activity saturates at L_x/L_bol ~ 10^-3 for log N_R < -0.8. However, super-saturation is not convincingly displayed by M-dwarfs, despite the presence of many objects in our sample with log N_R < -1.8, where super-saturation is observed to occur in higher mass stars. Instead, it appears that a short rotation period is the primary predictor of super-sa...

  18. Saturation and linear transport equation

    Energy Technology Data Exchange (ETDEWEB)

    Kutak, K.

    2009-03-15

    We show that the GBW saturation model provides an exact solution to the one dimensional linear transport equation. We also show that it is motivated by the BK equation considered in the saturated regime when the diffusion and the splitting term in the diffusive approximation are balanced by the nonlinear term. (orig.)

  19. Saturation and linear transport equation

    International Nuclear Information System (INIS)

    We show that the GBW saturation model provides an exact solution to the one dimensional linear transport equation. We also show that it is motivated by the BK equation considered in the saturated regime when the diffusion and the splitting term in the diffusive approximation are balanced by the nonlinear term. (orig.)

  20. Adaptive dynamics of saturated polymorphisms.

    Science.gov (United States)

    Kisdi, Éva; Geritz, Stefan A H

    2016-03-01

    We study the joint adaptive dynamics of n scalar-valued strategies in ecosystems where n is the maximum number of coexisting strategies permitted by the (generalized) competitive exclusion principle. The adaptive dynamics of such saturated systems exhibits special characteristics, which we first demonstrate in a simple example of a host-pathogen-predator model. The main part of the paper characterizes the adaptive dynamics of saturated polymorphisms in general. In order to investigate convergence stability, we give a new sufficient condition for absolute stability of an arbitrary (not necessarily saturated) polymorphic singularity and show that saturated evolutionarily stable polymorphisms satisfy it. For the case [Formula: see text], we also introduce a method to construct different pairwise invasibility plots of the monomorphic population without changing the selection gradients of the saturated dimorphism. PMID:26676357

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

    Science.gov (United States)

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

    2015-09-21

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

  2. Bacterial Degradation of Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Qing X. Li

    2009-01-01

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

  3. Effects of partial liquid/gas saturation on extensional wave attenuation in Berea sandstone

    Science.gov (United States)

    Yin, C.-S.; Batzle, M. L.; Smith, B. J.

    1992-07-01

    Extensional wave attenuation measurements on Berea sandstone were made during increasing (imbibition) and decreasing (drainage) brine saturations. Measurements on samples with both open-pore and closed-pore surfaces were made using the resonant-bar technique. The frequency dependence was examined using the forced-deformation method. The attenuation was found to be dependent on saturation history as well as degree of saturation and boundary flow conditions. The sample with open-pore surface had a larger attenuation which peaked at greater brine saturations than the sample with closed-pore surface. During drainage, the attenuation reached a maximum at about 90% brine saturation as opposed to about 97% brine saturation during imbibition. The variation of the size and number of air pockets within the rock can account for this discrepancy. The magnitude of the attenuation peak value decreases substantially with decreasing frequency to the extent that no attenuation peak with saturation was apparent at seismic frequencies, say, below 100 Hz.

  4. Saturated Subgraphs of the Hypercube

    OpenAIRE

    Johnson, J. Robert; Pinto, Trevor

    2014-01-01

    We say $G$ is \\emph{$(Q_n,Q_m)$-saturated} if it is a maximal $Q_m$-free subgraph of the $n$-dimensional hypercube $Q_n$. A graph, $G$, is said to be $(Q_n,Q_m)$-semi-saturated if it is a subgraph of $Q_n$ and adding any edge forms a new copy of $Q_m$. The minimum number of edges a $(Q_n,Q_m)$-saturated graph (resp. $(Q_n,Q_m)$-semi-saturated graph) can have is denoted by $sat(Q_n,Q_m)$ (resp. $s\\text{-}sat(Q_n,Q_m)$). We prove that $ \\lim_{n\\to\\infty}\\frac{sat(Q_n,Q_m)}{e(Q_n)}=0$, for fixed...

  5. Energy dependent saturable and reverse saturable absorption in cube-like polyaniline/polymethyl methacrylate film

    Energy Technology Data Exchange (ETDEWEB)

    Thekkayil, Remyamol [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India); Philip, Reji [Light and Matter Physics Group, Raman Research Institute, C.V. Raman Avenue, Bangalore 560 080 (India); Gopinath, Pramod [Department of Physics, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India); John, Honey, E-mail: honey@iist.ac.in [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695 547 (India)

    2014-08-01

    Solid films of cube-like polyaniline synthesized by inverse microemulsion polymerization method have been fabricated in a transparent PMMA host by an in situ free radical polymerization technique, and are characterized by spectroscopic and microscopic techniques. The nonlinear optical properties are studied by open aperture Z-scan technique employing 5 ns (532 nm) and 100 fs (800 nm) laser pulses. At the relatively lower laser pulse energy of 5 μJ, the film shows saturable absorption both in the nanosecond and femtosecond excitation domains. An interesting switchover from saturable absorption to reverse saturable absorption is observed at 532 nm when the energy of the nanosecond laser pulses is increased. The nonlinear absorption coefficient increases with increase in polyaniline concentration, with low optical limiting threshold, as required for a good optical limiter. - Highlights: • Synthesized cube-like polyaniline nanostructures. • Fabricated polyaniline/PMMA nanocomposite films. • At 5 μJ energy, saturable absorption is observed both at ns and fs regime. • Switchover from SA to RSA is observed as energy of laser beam increases. • Film (0.1 wt % polyaniline) shows high β{sub eff} (230 cm GW{sup −1}) and low limiting threshold at 150 μJ.

  6. Energy dependent saturable and reverse saturable absorption in cube-like polyaniline/polymethyl methacrylate film

    International Nuclear Information System (INIS)

    Solid films of cube-like polyaniline synthesized by inverse microemulsion polymerization method have been fabricated in a transparent PMMA host by an in situ free radical polymerization technique, and are characterized by spectroscopic and microscopic techniques. The nonlinear optical properties are studied by open aperture Z-scan technique employing 5 ns (532 nm) and 100 fs (800 nm) laser pulses. At the relatively lower laser pulse energy of 5 μJ, the film shows saturable absorption both in the nanosecond and femtosecond excitation domains. An interesting switchover from saturable absorption to reverse saturable absorption is observed at 532 nm when the energy of the nanosecond laser pulses is increased. The nonlinear absorption coefficient increases with increase in polyaniline concentration, with low optical limiting threshold, as required for a good optical limiter. - Highlights: • Synthesized cube-like polyaniline nanostructures. • Fabricated polyaniline/PMMA nanocomposite films. • At 5 μJ energy, saturable absorption is observed both at ns and fs regime. • Switchover from SA to RSA is observed as energy of laser beam increases. • Film (0.1 wt % polyaniline) shows high βeff (230 cm GW−1) and low limiting threshold at 150 μJ

  7. Creating pathways towards aromatic building blocks and fine chemicals.

    Science.gov (United States)

    Thompson, Brian; Machas, Michael; Nielsen, David R

    2015-12-01

    Aromatic compounds represent a broad class of chemicals with a range of industrial applications, all of which are conventionally derived from petroleum feedstocks. However, owing to a diversity of available pathway precursors along with natural and engineered enzyme 'parts', microbial cell factories can be engineered to create alternative, renewable routes to many of the same aromatic products. Drawing from the latest tools and strategies in metabolic engineering and synthetic biology, such efforts are becoming an increasingly systematic practice, while continued efforts promise to open new doors to an ever-expanding range and diversity of renewable chemical and material products. This short review will highlight recent and notable achievements related for the microbial production of aromatic chemicals. PMID:26264997

  8. Polybenzimidazoles Via Aromatic Nucleophilic Displacement

    Science.gov (United States)

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

    1997-01-01

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

  9. Bioassay of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Van Kirk, E.A.

    1980-08-01

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

  10. Micropropagation of different aromatic plants

    OpenAIRE

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

    2014-01-01

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

  11. Modified strip saturation model for a cracked piezoelectric strip

    Directory of Open Access Journals (Sweden)

    R.R. Bhargava

    2008-03-01

    Full Text Available Purpose: The investigations aim to propose a model for arresting an electrical opening of a crack which weakensa narrow, poled and infinite piezoelectric strip. The edges of the strip are subjected to uniform, constant anti-planestresses and in-plane electrical displacements.Design/methodology/approach: The loads applied at the edges of the strip open the crack in a self-similar fashion.Consequently at each tip of the crack a saturation zone protrudes. To stop the crack from further opening the rims ofdeveloped saturation zones are subjected to normal, cohesive linearly varying saturation limit electric displacement. Theedges of the strip are subjected to anti-plane deformation and in-plane electrical displacement. Fourier integral transformmethod employed reduces the problem to the solution of a Fredholm integral equation of second kind.Findings: The electrical displacement, stress intensity factor, the saturation zone length, crack opening displacementand crack growth rate have been calculated. The results obtained presented graphically, analysed and concluded.Research limitations/implications: The ceramic used for strip is being assumed to be electrically morebrittle. The investigations are carried at this level in the present paper. Also the small scale electrical yielding isconsidered. Consequently the developed saturation zone is proposed to lie in a line segment ahead of crack.Practical implications: Piezoelectric ceramics being widely used as transducers. Their wide utility hasprompted to study many attires of such ceramic and one such attire is fracture mechanics of these ceramics.Originality/value: The paper gives an assessment of the electrical load necessary to arrest the electrical crack opening.The investigations are useful to smart material design technology where sensors and actuators are manufactured.

  12. Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    Salama, Farid

    2010-01-01

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

  13. Modified strip saturation model for a cracked piezoelectric strip

    OpenAIRE

    R.R. Bhargava; A. Setia

    2008-01-01

    Purpose: The investigations aim to propose a model for arresting an electrical opening of a crack which weakensa narrow, poled and infinite piezoelectric strip. The edges of the strip are subjected to uniform, constant anti-planestresses and in-plane electrical displacements.Design/methodology/approach: The loads applied at the edges of the strip open the crack in a self-similar fashion.Consequently at each tip of the crack a saturation zone protrudes. To stop the crack from further opening t...

  14. Bacterial degradation of monocyclic aromatic amines

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar Arora

    2015-08-01

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

  15. Decentralized control with input saturation

    OpenAIRE

    Saberi, Ali; Stoorvogel, Anton A.; Sannuti, Peddapullaiah

    2004-01-01

    In decentralized control it is known that the system can be stabilized only if the so-called fixed modes are all stable. If we have input constraints then (semi-)global stability requires all poles to be in the closed left half plane. This paper establishes that these two requirements are necessary and sufficient for stabilizability of a decentralized system with input saturation.

  16. Exact expression for the effective acoustics of patchy-saturated rocks

    NARCIS (Netherlands)

    Vogelaar, B.; Smeulders, D.M.J.; Harris, J.

    2010-01-01

    Seismic effects of a partially gas-saturated subsurface have been known for many years. For example, patches of nonuniform saturation occur at the gas-oil and gas-water contacts in hydrocarbon reservoirs. Open-pore boundary conditions are applied to the quasi-static Biot equations of poroelasticity

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-02-26

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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Rajagopal Appavu

    2016-03-01

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

  20. Compositional changes of aromatic steroid hydrocarbons in naturally weathered oil residues in the Egyptian western desert

    International Nuclear Information System (INIS)

    Aromatic steranes are geochemical markers that can be used to study the maturation of organic matter of sediments and to correlate crude oils and source rocks. In this study, naturally weathered oil residues from an arid waste disposal site in Al-Alamein, Egypt, were analyzed for monoaromatic and triaromatic steranes to show the usefulness of biomarker compounds in assessing changes in chemical composition during the degradation of oil residues that have been released onto terrestrial environments. Gas chromatography and mass spectrometry were used to characterize the individual aromatic compounds. Results indicate that triaromatic sterane distributions are similar in oil residues with varying extents of weathering. The distribution correlated with a fresh crude oil sample from Western Desert-sourced oil. Molecular ratios of triaromatic sterane compounds were found to be suitable for source identification. The major changes in chemical compositions resulting from the weathering of the oil included the depletion of short chain mono- and tri-aromatic steranes in extremely weathered samples. The results of the triaromatic sterane distribution correspond with weathering classifications based on the analyses of saturated and aromatic hydrocarbons and the ratios of n-alkanes, polycyclic aromatic hydrocarbons, and saturate biomarker compounds. 15 refs., 3 tabs., 3 figs

  1. Sensory and aromatic characteristics of tongue sole by-products hydrolysates (Cynoglossus senegalensis)

    OpenAIRE

    Sylla, K. S. B.; Berge, Jean-pascal; PROST Carole; Musabyemariya, B.; Seydi, Mg

    2009-01-01

    Tongue sole by-products coming from fish-filleting plant were hydrolyzed by Protamex® protease. To identify the future application of hydrolysates, a sensory analysis was carried out.The sensory profile was performed with a jury of 14 specialized judges.11 profiles were found by this panel of tasting. In addition, the aromatic characterization revealed that 57 molecules are responsible for these odours described in sensory analysis.The description of these aromatic compounds opens potentia...

  2. Survey of Recent Innovations in Aromatic Rice

    OpenAIRE

    Napasintuwong, Orachos

    2012-01-01

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

  3. Catalytic ring opening of cyclic hydrocarbons in diesel fuels

    Energy Technology Data Exchange (ETDEWEB)

    Calemma, V.; Ferrari, M. [Eni S.p.A., San Donato Milanese (Italy). R and M Div.; Rabl, S.; Haas, A.; Santi, D.; Weitkamp, J. [Stuttgart Univ. (Germany). Inst. of Chemical Technology

    2013-11-01

    An approach for high-aromatic streams upgrading, allowing to meet future diesel quality standards, is saturation of the aromatic structures followed by the selective breaking of endocyclic C-C bonds of naphthenic structures so formed to produce alkanes with the same number of carbon atoms as the starting molecule ('selective ring opening, SRO'). Although theoretically, SRO is a promising route for upgrading low-value feeds to high-quality products, in practice, it continues to be a challenge owing to its complex chemistry. Product characteristics, do not only depend on the composition of the feed, but also on the operating conditions and the nature of the catalyst. Very recently, novel catalysts ('HIgh-PErformance Ring Opening Catalysts, HIPEROCs') were developed which allow a very selective ring opening of the model compound decalin to paraffins without degradation of the carbon number. The hydroconversion of dearomatized Light Cycle Oil (DeAr-LCO) over the abovementioned catalysts resulted in a remarkable change of the chemical structure of the feed with a strong decrease of naphthenic structures with two or more condensed rings and a concomitant increase of alkyl-substituted cyclohexanes and open-chain alkanes. The changes occurring in the chemical structures of feedstock during hydroconversion resulted in a remarkable increase of the Cetane Index of the products up to 11 units. In the present contribution, we examine the main factors affecting activity and selectivity of SRO catalysts in the light of the recent literature dealing with the subject and we report on the recent advances in hydroconversion of refinery cuts such as DeAr- LCO over HIPEROCs. (orig.)

  4. Saturation of repeated quantum measurements

    Science.gov (United States)

    Haapasalo, Erkka; Heinosaari, Teiko; Kuramochi, Yui

    2016-08-01

    We study sequential measurement scenarios where the system is repeatedly subjected to the same measurement process. We first provide examples of such repeated measurements where further repetitions of the measurement do not increase our knowledge on the system after some finite number of measurement steps. We also prove, however, that repeating the Lüders measurement of an unsharp two-outcome observable never saturates in this sense, and we characterize the observable measured in the limit of infinitely many repetitions. Our result implies that a repeated measurement can be used to correct the inherent noise of an unsharp observable.

  5. Saturation Physics: Probes and Signatures

    International Nuclear Information System (INIS)

    A hadron wavefunction at high energy contains many gluons which carry a small fraction x of the valence quark energy. At fixed impact parameters as one increases the hadron energy, the gluon occupation number in the wavefunction eventually saturates and becomes of order of 1/αs, the maximum allowed by QCD. The resulting hadron state at high energy is then called a Color Glass Condensate (CGC). Signatures and predictions of the formalism are reviewed and compared with the experimental data at RHIC.

  6. Gluon Evolution and Saturation Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    McLerran, L.D.

    2010-05-26

    Almost 40 years ago, Gribov and colleagues at the Leningrad Nuclear Physics Institute developed the ideas that led to the Dokhsitzer-Gribov-Altarelli-Parisi the Baltisky-Fadin-Kuraev-Lipatov equations. These equations describe the evolution of the distributions for quarks and gluon inside a hadron to increased resolution scale of a probe or to smaller values of the fractional momentum of a hadronic constituent. I motivate and discuss the generalization required of these equations needed for high energy processes when the density of constituents is large. This leads to a theory of saturation realized by the Color Glass Condensate

  7. A three-step process to facilitate the annulation of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Martin, Sara E; Streeter, Matthew D; Jones, Laurel L; Klepfer, Matthew S; Atmatzidis, Kyriakos; Wille, Kristen D; Harrison, Sean A; Hoegg, Edward D; Sheridan, Heather M; Kramer, Stephanie; Parrish, Damon A; Amick, Aaron W

    2014-09-01

    A new efficient three-step process to annulate polycyclic aromatic hydrocarbons (PAHs) has been developed, providing access to PAHs with saturated rings that under current chemical methods would be difficult to produce in an efficient manner. This method relies on a palladium-catalyzed cross-coupling reaction of various brominated PAHs with cyclohexanone to yield α-arylated ketones, which are converted to regiospecific vinyl triflates and cyclized by a palladium-catalyzed intramolecular arene-vinyl triflate coupling to produce PAHs with incorporated saturated rings or "tetrahydroindeno-annulated" PAHs. PMID:25137354

  8. A phenomenological modeling of critical condensate saturation

    Energy Technology Data Exchange (ETDEWEB)

    Fang, F.; Firoozabadi, A.; Abbaszadeh, M. [and others

    1996-12-31

    We have developed a phenomenological model for critical condensate saturation. This model reveals that critical condensate saturation is a function of surface tension and contact angle hysteresis. On the other hand, residual oil saturation does not have such a dependency. Consequently, the selection of fluids in laboratory measurements for gas condensate systems should be made with care.

  9. Nucleophilic fluorination of aromatic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Satyamurthy, Nagichettiar; Barrio, Jorge R

    2014-03-18

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

  10. Biodegradation of Polycyclic Aromatic Hydrocarbons

    OpenAIRE

    DEMİR, İsmail; DEMİRBAĞ, Zihni

    1999-01-01

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

  11. Analysis of heterocyclic aromatic amines.

    Science.gov (United States)

    Murkovic, M

    2007-09-01

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

  12. Deuterated polycyclic aromatic hydrocarbons: Revisited

    CERN Document Server

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

    2016-01-01

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

  13. The direct aromatization of methane

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-31

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

  14. Mechanics of non-saturated soils

    International Nuclear Information System (INIS)

    This book presents the different ways to approach the mechanics of non saturated soils, from the physico-chemical aspect to the mechanical aspect, from the experiment to the theoretical modeling, from the laboratory to the workmanship, and from the microscopic scale to the macroscopic one. Content: water and its representation; experimental bases of the behaviour of non-saturated soils; transfer laws in non-saturated environment; energy approach of the behaviour of non-saturated soils; homogenization for the non-saturated soils; plasticity and hysteresis; dams and backfilling; elaborated barriers. (J.S.)

  15. Semiconductor saturable absorbers for ultrafast terahertz signals

    DEFF Research Database (Denmark)

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    2010-01-01

    We demonstrate saturable absorber behavior of n-type semiconductors GaAs, GaP, and Ge in the terahertz THz frequency range at room temperature using nonlinear THz spectroscopy. The saturation mechanism is based on a decrease in electron conductivity of semiconductors at high electron momentum...... states, due to conduction band onparabolicity and scattering into satellite valleys in strong THz fields. Saturable absorber parameters, such as linear and nonsaturable transmission, and saturation fluence, are extracted by fits to a classic saturable absorber model. Further, we observe THz pulse...

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

    OpenAIRE

    Muhajir Marsaoli

    2004-01-01

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

  17. The use of polynuclear aromatic hydrocarbon (PAH) alkyl homologues in determining petroleum source identification and weathering

    International Nuclear Information System (INIS)

    Techniques utilizing double ratio plots of selected polynuclear aromatic hydrocarbon (PAH) alkyl homologues were used to identify and distinguish crude oils and refined petroleum products from each other and to distinguish petroleum sources in complex pollutant regimes. Petroleum samples were fractionated by high performance liquid chromatography (HPLC) into saturated and aromatic (PAH) hydrocarbon fractions. The saturated hydrocarbon fractions were then analyzed by gas chromatography/flame ionization detection (GC/FID) to obtain a resolved/unresolved alkane fingerprint of each oil. The aromatic fractions of the oils were analyzed by gas chromatography/mass spectrometry (GC/MS) for PAH and selected alkyl homologues. Comparisons of the saturated hydrocarbon fingerprints indicated that some oils were indistinguishable based on the alkane fingerprint alone. Another double ratio plot of the alkyl chrysenes and alkyl dibenzothiophenes was effective in establishing the weathering of oil in environmental samples which were processed using the same analytical techniques, since the dibenzothiophenes are degraded more rapidly than the chrysenes. The application of selected ratios in oil spill source identification in complex environmental samples from Suisin Bay California and Boston Harbor are discussed. The use of ratios to measure the extent of weathering in oil spill samples from Prince William Sound and the Gulf of Alaska is examined

  18. Noncomparative scaling of aromaticity through electron itinerancy

    International Nuclear Information System (INIS)

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

  19. Measuring tissue oxygen saturation using NIR spectroscopy

    Science.gov (United States)

    Sircan-Kucuksayan, Aslinur; Uyuklu, Mehmet; Canpolat, Murat

    2014-05-01

    Tissue oxygen saturation (StO2) is known quite useful parameter for medical applications. A spectroscopic method has been developed to diagnose pathologic tissues due to lack of normal blood circulation by measuring tissue oxygen saturation. In the study, human blood samples with different level of oxygen saturations have been prepared and spectra were taken using an optical fiber probe to investigate correlation between the oxygen saturations and the spectra. The experimental set up for the spectroscopic measurements was consists of a miniature NIR light spectrometer, an optical fiber probe, a halogen-tungsten light source and a laptop. A linear correlation between the oxygen saturation of the blood samples and the ratio of the light of wavelengths 660 nm to 790 nm has been found from the spectra. Then, oxygen saturations of the blood samples were estimated from the spectroscopic measurements within an error of 2.9%. Furthermore, it has been shown that the linear dependence between the ratio and the oxygen saturation of the blood samples was valid for the blood samples with different hematocrits. Tissue oxygen saturation has been estimated from the spectroscopic measurements were taken from the fingers of healthy volunteers using the correlation between the spectra and blood oxygen saturation. The tissue StO2 measured was 80% as expected. The technique developed to measure tissue oxygen saturation has potential to diagnose premalignant tissues, follow up prognosis of cancerous tissues, and evaluation of ischemia reperfusion tissues.

  20. Saturation of the Electric Field Transmitted to the Magnetosphere

    Science.gov (United States)

    Lyatsky, Wladislaw; Khazanov, George V.; Slavin, James A.

    2010-01-01

    We reexamined the processes leading to saturation of the electric field, transmitted into the Earth's ionosphere from the solar wind, incorporating features of the coupled system previously ignored. We took into account that the electric field is transmitted into the ionosphere through a region of open field lines, and that the ionospheric conductivity in the polar cap and auroral zone may be different. Penetration of the electric field into the magnetosphere is linked with the generation of the Alfven wave, going out from the ionosphere into the solar wind and being coupled with the field-aligned currents at the boundary of the open field limes. The electric field of the outgoing Alfven wave reduces the original electric field and provides the saturation effect in the electric field and currents during strong geomagnetic disturbances, associated with increasing ionospheric conductivity. The electric field and field-aligned currents of this Alfven wave are dependent on the ionospheric and solar wind parameters and may significantly affect the electric field and field-aligned currents, generated in the polar ionosphere. Estimating the magnitude of the saturation effect in the electric field and field-aligned currents allows us to improve the correlation between solar wind parameters and resulting disturbances in the Earth's magnetosphere.

  1. Quantum transport through aromatic molecules

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Agnieszka Mironowicz; Krystyna Kukułczanka; Antoni Siewiński

    2014-01-01

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

  3. Power flow control using distributed saturable reactors

    Science.gov (United States)

    Dimitrovski, Aleksandar D.

    2016-02-13

    A magnetic amplifier includes a saturable core having a plurality of legs. Control windings wound around separate legs are spaced apart from each other and connected in series in an anti-symmetric relation. The control windings are configured in such a way that a biasing magnetic flux arising from a control current flowing through one of the plurality of control windings is substantially equal to the biasing magnetic flux flowing into a second of the plurality of control windings. The flow of the control current through each of the plurality of control windings changes the reactance of the saturable core reactor by driving those portions of the saturable core that convey the biasing magnetic flux in the saturable core into saturation. The phasing of the control winding limits a voltage induced in the plurality of control windings caused by a magnetic flux passing around a portion of the saturable core.

  4. Raman-Nath thin gratings of low-saturated dynamic recording materials

    Directory of Open Access Journals (Sweden)

    S.Bugaychuk

    2002-03-01

    Full Text Available The holographic kinetics of organic polymer thin films with low-saturated absorption are considered both for self-diffraction and diffraction of a weak probe beam in Raman-Nath conditions. The coupling effect between different diffracted orders is taking into account. The coupling effect results in considerable increase of the diffraction efficiency of self-diffracted beams compared with the diffraction of the probe beam were shown. For the region of deep saturation the maximum diffraction efficiency is higher than in the region far from the saturation. The maximum of diffraction efficiency is reached for considerable shorter time in grating recording kinetics in the region of deep saturation. This opens the perspective of using those materials for novelty filter. The experimental results on low-saturated dry bacteriorhodopsin films well agree the theoretical predictions.

  5. Can a Bose Gas Be Saturated?

    International Nuclear Information System (INIS)

    We scrutinize the concept of saturation of the thermal component in a partially condensed trapped Bose gas. Using a 39K gas with tunable interactions, we demonstrate strong deviation from Einstein's textbook concept of a saturated vapor. However, the saturation picture can be recovered by extrapolation to the strictly noninteracting limit. We provide evidence for the universality of our observations through additional measurements with a different atomic species, 87Rb.

  6. THz saturable absorption in turbostratic multilayer graphene on silicon carbide.

    Science.gov (United States)

    Bianco, Federica; Miseikis, Vaidotas; Convertino, Domenica; Xu, Ji-Hua; Castellano, Fabrizio; Beere, Harvey E; Ritchie, David A; Vitiello, Miriam S; Tredicucci, Alessandro; Coletti, Camilla

    2015-05-01

    We investigated the room-temperature Terahertz (THz) response as saturable absorber of turbostratic multilayer graphene grown on the carbon-face of silicon carbide. By employing an open-aperture z-scan method and a 2.9 THz quantum cascade laser as source, a 10% enhancement of transparency is observed. The saturation intensity is several W/cm2, mostly attributed to the Pauli blocking effect in the intrinsic graphene layers. A visible increase of the modulation depth as a function of the number of graphene sheets was recorded as consequence of the low nonsaturable losses. The latter in turn revealed that crystalline disorder is the main limitation to larger modulations, demonstrating that the THz nonlinear absorption properties of turbostratic graphene can be engineered via a proper control of the crystalline disorder and the layers number. PMID:25969255

  7. Does deformation saturate seismic anisotropy?

    Science.gov (United States)

    Tatham, D. J.; Lloyd, G. E.; Butler, R. W.; Casey, M.

    2006-12-01

    The progressive simple shear deformation that characterizes ductile fault zones in the crust involves both rotation and intensification of the strain ellipsoid. These mathematic predictions have been confirmed repeatedly by finite strain determinations in outcrop studies of natural shear zones and used to test geodynamic models of mountain belts. Seismic anisotropy (SA) methods offer the opportunity to pursue these approaches in situ. First however, we must calibrate the magnitude and orientation of the SA ellipsoid against naturally deformed tectonites of known strain state and microstructure. Here we present data from a field analogue of mafic ductile crust in an amphibolite-facies shear zone developed in a deformed mafic dyke embedded within the Lewisian Gneiss (Badcall, NW Scotland). Deflection of pre-existing linear and planar elements and attenuation of the dyke into the shear zone are used to determine the strain gradient. Specimens collected along this gradient were used to establish the geometric fabric intensity defined by different minerals (hornblende grain alignment and ellipticity of plagioclase clots). Finally, petrophysical properties were calculated for the specimens using the SEM-EBSD measured populations of lattice preferred orientations (LPO) for all mineral phases. It is the hornblende-plagioclase LPO, combined in their modal proportions and modulated by the individual mineral single crystal elastic properties, which define the SA profile across the shear zone. Hornblende develops a strong preferred dimensional orientation and hence LPO at shear strains of about 2, whereas the plagioclase LPO remains close to random regardless of bulk strain. The modelled SA of the samples is dominated therefore by the amphibole LPO. Although the values of bulk shear strain vary across the shear zone (0 at the margins to greater than 12 in the centre), the calculated intensity of SA saturates at a shear strain of about 2. These results, if typical of large

  8. The potential production of aromatic compounds in flowers of Vanda tricolor

    Science.gov (United States)

    Darmasiwi, Sari; Indriani, Vitri; Innata, Dita; Semiarti, Endang

    2015-09-01

    Vanda tricolor is a famous natural orchid that has beautiful flowers with fragrance, therefore analysis of aromatic compounds of this orchid are important. The objective of this research was to isolate and identify the aromatic compounds of Vanda tricolor flower. The flower petals were picked at various developmental stages (0,4,7, and 10 days of flower opened) at 12.00 noon. It was then extracted using solvent extraction method and enfleurage method. The hexane:acetone (9:1) extract was considered as concrete extract, while some parts of concrete that were further extracted with ethanol, considered as absolute extract. The olive oil extract was considered as enfleurage extract. Those extracts were then evaporated using nitrogen gas, and analyzed by GC/MS (GC/MS-QP 2010S Shimadzu, Agilent HP-5 MS UI column, 30 m ID length: 0.25 mm, Helium gas carrier). The results showed that aromatic compounds composition in Vanda tricolor flower extracts were consisted of fatty acid derivates, monoterpenoids, sesquiterpenoids, benzenoids, phenylpropanoids, hydrocarbons and other oxygenated compounds. The highest diversity of aromatic compounds were found at the 10th days after floral opened, and the sensory test among those 3 (three) extracts showed that the absolute extract had more similarity with the original flower scent profile rather than the other extracts. This research showed that Vanda tricolor has potential production of aromatic compounds which was different compare to another species of Vanda.

  9. Beyond organic chemistry: aromaticity in atomic clusters.

    Science.gov (United States)

    Boldyrev, Alexander I; Wang, Lai-Sheng

    2016-04-28

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

  10. Multiscale optimization of saturated poroelastic actuators

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe; Sigmund, Ole

    A multiscale method for optimizing the material micro structure in a macroscopically heterogeneous saturated poroelastic media with respect to macro properties is presented. The method is based on topology optimization using the homogenization technique, here applied to the optimization of a bi......-morph saturated poroelastic actuator....

  11. Saturated poroelastic actuators generated by topology optimization

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe; Sigmund, Ole

    2011-01-01

    In this paper the fluid-structure interaction problem of a saturated porous media is considered. The pressure coupling properties of porous saturated materials change with the microstructure and this is utilized in the design of an actuator using a topology optimized porous material. By maximizin...

  12. Saturation and geometrical scaling in small systems

    CERN Document Server

    Praszalowicz, Michal

    2016-01-01

    Saturation and geometrical scaling (GS) of gluon distributions are a consequence of the non-linear evolution equations of QCD. We argue that in pp GS holds for the inelastic cross-section rather than for the multiplicity distributions. We also discuss possible fluctuations of the proton saturation scale in pA collisions at the LHC.

  13. Ultrafast THz Saturable Absorption in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hoffmann, Matthias C.

    2011-01-01

    We demonstrate THz saturable absorption in n-doped semiconductors GaAs, GaP, and Ge in a nonlinear THz time-domain spectroscopy experiment. Saturable absorption is caused by sample conductivity modulation due to electron heating and satellite valley scattering in the field of a strong THz pulse....

  14. Fault tolerant control of systems with saturations

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2013-01-01

    This paper presents framework for fault tolerant controllers (FTC) that includes input saturation. The controller architecture known from FTC is based on the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization is extended to handle input saturation. Applying this controller architecture in connec...

  15. Zircon Saturation Re-Revisited

    Science.gov (United States)

    Boehnke, P.; Trail, D.; Schmitt, A. K.; Watson, E. B.; Harrison, M.

    2011-12-01

    Zircon saturation in silicate melts has been utilized for magma thermometry and predicting the survival of zircon xenocrysts in crustal melts for nearly 30 years. The original calibration, which assumed only compositional (M = [2Ca+Na+K]/[AlxSi]) and temperature controls, was bolstered by subsequent experimental investigations and thermometry of volcanic rocks and glasses. These latter studies, while confirming the general predictions of the model, suggested that other environmental parameters (e.g., pressure, H 2O, halogens, [Fe], oxygen fugacity, etc.) might have second-order effects. Given the tremendous advances in micro-analytical capabilities over the intervening three decades, we have returned to this question with a view to obtaining a refined zircon solubility calibration as a function of P, T, [H2O] and FM (= [Na+K+2(Ca+Mg+Fe)]/[AlxSi]). Detailed SEM imaging of the original low-temperature crystallization experiments (1.2-2.1 kbar) revealed limitations of this approach and we chose instead to use a new experimental design in which shattered Mud Tank zircon is infiltrated by melts of selected composition and water contents. 10 kbar hydrothermal experiments (925o and 850oC) were run for sufficiently long durations (2 to 3 days) to ensure microscale diffusive equilibration of Zr released by zircon dissolution into the intercrystalline melt pools. Sectioned run products were analyzed by SIMS ion imaging of selected areas where glass is exposed in close proximity to or surrounded by Mud Tank zircon fragments. Ion imaging has the advantage of permitting high spatial resolution (3 μm) analysis of the glasses allowing assessment of Zr equilibration. Using synthetic glass standards, we found [Zr] in anhydrous glasses to be enhanced by ca. 20% relative to hydrous (at 6 wt.% H2O). Our new experiments and re-analysis of the earlier glasses broadly reproduce the original calibration, albeit with substantially enhanced (factor of five) precision compared to the

  16. Groundwater: Saturated and Unsaturated Zone

    International Nuclear Information System (INIS)

    The interpretation of isotope hydrological data is not straightforward. Many field studies lead to a conclusion that the origin of groundwater and the chemical and isotopic processes in groundwater systems can only be studied successfully, if a composition of isotopic, chemical, geological and hydrogeological data is available for interpretation. Following the previous volumes on isotopic principles, precipitation and surface waters, this volume is dealing with the application of isotope hydrological methods in groundwater studies. It conveys basic knowledge in geohydraulics and hydrogeology required for a consistent interpretation of isotope hydrological data. This volume starts with a brief discussion of the characteristics and behaviour of groundwater as a medium of mass transport for gases, dissolved constituents and colloids. The geohydraulic aspects of groundwater flow under steady-state conditions are described in combination with an explanation of the most important terms related to isotope hydrology (e.g. transit time, turn-over time, mean residence time, water age). Non-steady state flow conditions caused by palaeoclimatic variations and anthropogenic activities such as overexploitation or groundwater mining seriously affect the interpretation of isotope hydrological data. Also water-rock interactions may modify the isotope composition of a carbonate rock environment, especially in high-temperature systems. Environmental isotope techniques are pre-eminently suitable for studying the unsaturated and saturated zone, the latter particularly concerning the stable and radioactive natural isotopes. Stable isotope data preferentially yield information on the origin of groundwater. Radioactive isotopes allow groundwater to be 'dated' in support of geohydraulic investigations. In undisturbed high-temperature systems isotopic geothermometry, i.e. the study of the temperature effect of stable isotopic abundances, is applied for gaining information on water mixing as

  17. Polycyclic aromatic hydrocarbons with SPICA

    CERN Document Server

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

    2009-01-01

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

  18. Evaluation of the Performance of Grouting Materials for Saturated Riprap

    Directory of Open Access Journals (Sweden)

    Daehyeon Kim

    2013-12-01

    Full Text Available In this study, four types of grout were developed to evaluate the effect of grouting of saturated riprap layers on ground water flow. The developed types of grout are divided into a quick-setting type and a general-type, and also into high and low viscosities. A number of grout tests were performed in a model acrylic chamber, 0.4 m in diameter and 2.0 m in length, for visual observation of injection. To reproduce the field flow condition of the saturated riprap layers (approach flow, the grout tests were carried out at 0 cm/s and 100 cm/s for the flow speed and 10 L/min for the grout injection speed after installing a flow injection opening on the lower part of the chamber. Based on the results of the grout tests, the injection of each grout in the saturated riprap layers was examined to find out the most effective grout.

  19. Translation of an aromatic field image

    Science.gov (United States)

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

    2005-04-01

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

  20. Uniquely K_r-Saturated Graphs

    CERN Document Server

    Hartke, Stephen G

    2012-01-01

    A graph G is uniquely K_r-saturated if it contains no clique with r vertices and if for all edges e in the complement, G + e has a unique clique with r vertices. Previously, few examples of uniquely K_r-saturated graphs were known, and little was known about their properties. We search for these graphs by adapting orbital branching, a technique originally developed for symmetric integer linear programs. We find several new uniquely K_r-saturated graphs with 4 \\leq r \\leq 7, as well as two new infinite families based on Cayley graphs for Z_n with a small number of generators.

  1. SATURATION BIOPSY OF THE PROSTATE (REVIEW

    Directory of Open Access Journals (Sweden)

    A. V. Sadchenko

    2014-07-01

    Full Text Available Prostate biopsy is the principal method of diagnois of prostate cancer, allowing to start the adequate treatment. The tactics of the patients, which have negative initial biopsy, is a subject of discussion. Saturation biopsy is a “gold standard„ of diagnostics of PCA with repeat biopsy. Saturation biopsy of the prostate is not a primary procedure, usually apply in patients with negative biopsies in anamnesis, patients with multifocal PIN and ASAP. Saturation biopsy allows to more precisely predict the volume and degree of malignancy of PCA, that can be used for planning tactics of active surveillance and focal therapy.

  2. Scintillation probe with photomultiplier tube saturation indicator

    Science.gov (United States)

    Ruch, Jeffrey F.; Urban, David J.

    1996-01-01

    A photomultiplier tube saturation indicator is formed by supplying a supplemental light source, typically an light emitting diode (LED), adjacent to the photomultiplier tube. A switch allows the light source to be activated. The light is forwarded to the photomultiplier tube by an optical fiber. If the probe is properly light tight, then a meter attached to the indicator will register the light from the LED. If the probe is no longer light tight, and the saturation indicator is saturated, no signal will be registered when the LED is activated.

  3. Conservation of medicinal and aromatic plants

    Directory of Open Access Journals (Sweden)

    Šveistytė, Laima

    2016-07-01

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

  4. Aromaticity influencing the thermostability of micellar dispersions

    Energy Technology Data Exchange (ETDEWEB)

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

    1970-02-17

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

  5. Hexacoordinate bonding and aromaticity in silicon phthalocyanine.

    Science.gov (United States)

    Yang, Yang

    2010-12-23

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

  6. Benzo-thia-fused [n]Thienoacenequinodimethanes with Small to Moderate Diradical Characters: The Role of Pro-aromaticity versus Anti-aromaticity

    KAUST Repository

    Shi, Xueliang

    2016-01-19

    Open-shell singlet diradicaloids recently have received much attention due to their unique optical, electronic and magnetic properties and promising applications in materials science. Among various diradicaloids, quinoidal π-conjugated molecules have become the prevailing designs. However, there still lacks fundamental understanding on how the fusion mode and pro-aromaticity/anti-aromaticity affect their diradical character and physical properties. In this work, a series of pro-aromatic benzo-thia-fused [n]thienoacenequinodimethanes (Thn-TIPS (n=1-3) and BDTh-TIPS) were synthesized and compared with the previously reported anti-aromatic bisindeno-[n]thienoacenes (Sn-TIPS, n=1-4). The ground-state geometric and electronic structures of these new quinoidal molecules were systematically investigated by X-ray crystallographic analysis, variable temperature NMR, ESR, SQUID, Raman, and electronic absorption spectroscopy, assisted by DFT calculations. It was found that the diradical character index (y0) increased from nearly zero for Th1-TIPS to 2.4% for Th2-TIPS, 18.2% for Th3-TIPS, and 38.2% for BDTh-TIPS, due to the enhanced aromatic stabilization. Consequently, with the extension of molecular size, the one-photon absorption spectra are gradually red-shifted, the two-photon absorption (TPA) cross section values increase, and the singlet excited state lifetimes decrease. By comparison with the corresponding anti-aromatic analogues Sn-TIPS (n=1-3), the pro-aromatic Thn-TIPS (n=1-3) exhibit larger diradical character, longer singlet excited state lifetime and larger TPA cross section value. At the same time, they display distinctively different electronic absorption spectra and improved electrochemical amphotericity. Spectroelectrochemical studies revealed a good linear relationship between the optical energy gaps and the molecular length in the neutral, radical cationic and dicationic forms. Our research work disclosed the significant difference between the pro-aromatic

  7. Estrogenic Activity of Mineral Oil Aromatic Hydrocarbons Used in Printing Inks.

    Directory of Open Access Journals (Sweden)

    Patrick Tarnow

    Full Text Available The majority of printing inks are based on mineral oils (MOs which contain complex mixtures of saturated and aromatic hydrocarbons. Consumer exposure to these oils occurs either through direct skin contacts or, more frequently, as a result of MO migration into the contents of food packaging that was made from recycled newspaper. Despite this ubiquitous and frequent exposure little is known about the potential toxicological effects, particularly with regard to the aromatic MO fractions. From a toxicological point of view the huge amount of alkylated and unsubstituted compounds therein is reason for concern as they can harbor genotoxicants as well as potential endocrine disruptors. The aim of this study was to assess both the genotoxic and estrogenic potential of MOs used in printing inks. Mineral oils with various aromatic hydrocarbon contents were tested using a battery of in vitro assays selected to address various endpoints such as estrogen-dependent cell proliferation, activation of estrogen receptor α or transcriptional induction of estrogenic target genes. In addition, the comet assay has been applied to test for genotoxicity. Out of 15 MOs tested, 10 were found to potentially act as xenoestrogens. For most of the oils the effects were clearly triggered by constituents of the aromatic hydrocarbon fraction. From 5 oils tested in the comet assay, 2 showed slight genotoxicity. Altogether it appears that MOs used in printing inks are potential endocrine disruptors and should thus be assessed carefully to what extent they might contribute to the total estrogenic burden in humans.

  8. Estrogenic Activity of Mineral Oil Aromatic Hydrocarbons Used in Printing Inks

    Science.gov (United States)

    Tarnow, Patrick; Hutzler, Christoph; Grabiger, Stefan; Schön, Karsten; Tralau, Tewes; Luch, Andreas

    2016-01-01

    The majority of printing inks are based on mineral oils (MOs) which contain complex mixtures of saturated and aromatic hydrocarbons. Consumer exposure to these oils occurs either through direct skin contacts or, more frequently, as a result of MO migration into the contents of food packaging that was made from recycled newspaper. Despite this ubiquitous and frequent exposure little is known about the potential toxicological effects, particularly with regard to the aromatic MO fractions. From a toxicological point of view the huge amount of alkylated and unsubstituted compounds therein is reason for concern as they can harbor genotoxicants as well as potential endocrine disruptors. The aim of this study was to assess both the genotoxic and estrogenic potential of MOs used in printing inks. Mineral oils with various aromatic hydrocarbon contents were tested using a battery of in vitro assays selected to address various endpoints such as estrogen-dependent cell proliferation, activation of estrogen receptor α or transcriptional induction of estrogenic target genes. In addition, the comet assay has been applied to test for genotoxicity. Out of 15 MOs tested, 10 were found to potentially act as xenoestrogens. For most of the oils the effects were clearly triggered by constituents of the aromatic hydrocarbon fraction. From 5 oils tested in the comet assay, 2 showed slight genotoxicity. Altogether it appears that MOs used in printing inks are potential endocrine disruptors and should thus be assessed carefully to what extent they might contribute to the total estrogenic burden in humans. PMID:26771904

  9. Crack arrest saturation model under combined electrical and mechanical loadings

    Directory of Open Access Journals (Sweden)

    R.R. Bhargava

    2009-12-01

    Full Text Available Purpose: The investigation aims at proposing a model for cracked piezoelectric strip which is capable to arrest the crack.Design/methodology/approach: Under the combined effect of electrical and mechanical loadings applied at the edges of the strip, the developed saturation zone is produced at each tip of the crack. To arrest further opening of the crack, the rims of the developed saturation zones are subjected to in-plane cohesive, normal uniform constant saturation point electrical displacement. The problem is solved using Fourier integral transform method which reduces the problem to the solution of Fredholm integral equation of the second kind. This integral equation in turn is solved numerically.Findings: The expressions are derived for different intensity factors and energy release rate. A qualitative analysis of the parameters affecting the arrest of opening of the crack and fatigue crack growth with respect to strip thickness and material constants are presented graphically.Research limitations/implications: The investigations are carried out by considering the material electrical brittle. Consequently, the zones protrude along the straight lines ahead of the crack tips. And further, the small scale electrical yielding conditions are used.Practical implications: Piezoelectric materials are widely getting used nowadays, even in day to day life like piezoelectric cigarette lighter, children toys etc. And, its advance used in technology like transducers, actuators has been already in progress. So, the aspect of cracking of piezoelectric materials are of great practical importance.Originality/value: The piezoelectric material under the combined effect of electrical and mechanical loadings gives the assessment of electrical displacement which is required to arrest the crack. The various useful interpretations are also drawn from the graphs.

  10. The Perturbational MO Method for Saturated Systems.

    Science.gov (United States)

    Herndon, William C.

    1979-01-01

    Summarizes a theoretical approach using nonbonding MO's and perturbation theory to correlate properties of saturated hydrocarbons. Discussion is limited to correctly predicted using this method. Suggests calculations can be carried out quickly in organic chemistry. (Author/SA)

  11. Saturated thickness, High Plains aquifer, 2009

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents the saturated thickness of the High Plains aquifer of the United States, 2009, in feet. The High Plains aquifer underlies...

  12. Saturation of biphoton generation near atomic resonance

    Institute of Scientific and Technical Information of China (English)

    Chen Peng; Qian Jun; Hu Zheng-Feng; Wang Yu-Zhu

    2012-01-01

    We have numerically investigated the biphoton generation rate as a function of several parameters in the spontaneous four-wave mixing in cold atoms.It has been found that the biphoton generation rate can easily reach saturation with the intensity of the coupling laser increasing.The saturation intensity is mainly dependent on the dephasing rate of the ground states,unrelated to the pumping laser.It implies that though the biphoton waveform can be manipulated by the coupling laser,the generation rate of the biphoton cannot increase markedly after the saturation.The saturation effect also suggests that there is an optimal coupling laser for obtaining the largest biphoton generation rate with a sufficiently long coherence time.

  13. Combinatorics of saturated secondary structures of RNA.

    Science.gov (United States)

    Clote, P

    2006-11-01

    Following Zuker (1986), a saturated secondary structure for a given RNA sequence is a secondary structure such that no base pair can be added without violating the definition of secondary structure, e.g., without introducing a pseudoknot. In the Nussinov-Jacobson energy model (Nussinov and Jacobson, 1980), where the energy of a secondary structure is -1 times the number of base pairs, saturated secondary structures are local minima in the energy landscape, hence form kinetic traps during the folding process. Here we present recurrence relations and closed form asymptotic limits for combinatorial problems related to the number of saturated secondary structures. In addition, Python source code to compute the number of saturated secondary structures having k base pairs can be found at the web servers link of bioinformatics.bc.edu/clotelab/. PMID:17147486

  14. PROGRESS IN CATALYST AND PROCESS DEVELOPMENT FOR LOW SULFUR AND LOW AROMATICS DIESEL PRODUCTION%低硫低芳烃柴油生产技术开发进展

    Institute of Scientific and Technical Information of China (English)

    周勇; 韩崇仁

    2003-01-01

    The article includes three parts: ①The development and performance of FH-DS catalyst for deep and ultra-deep distillate HDS; ②The single stage HDS/HDA hydrotreating process for the production of low sulfur and low aromatics diesels from straight run and coker AGO by using highly active base metal catalyst at moderate pressure; ③A two-stage aromatics saturation system utilizing noble metal catalyst in the second stage developed for production of low sulfur and low aromatics diesel from LCO. FDA catalyst developed by FRIPP has high activity for aromatics saturation together with high tolerance for sulfur and nitrogen in the feed. The process is effective in reducing density and increasing cetane number.

  15. Ultrafast THz Saturable Absorption in Doped Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hoffmann, Matthias C.

    2011-01-01

    We demonstrate ultrafast THz saturable absorption in n-doped semiconductors by nonlinear THz time-domain spectroscopy. This effect is caused by the semiconductor conductivity modulation due to electron heating and satellite-valley scattering in strong THz fields.......We demonstrate ultrafast THz saturable absorption in n-doped semiconductors by nonlinear THz time-domain spectroscopy. This effect is caused by the semiconductor conductivity modulation due to electron heating and satellite-valley scattering in strong THz fields....

  16. Semiconductor saturable absorbers for ultrafast THz signals

    DEFF Research Database (Denmark)

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    We demonstrate saturable absorber behavior of n-type semiconductors in the THz frequency range using nonlinear THz spectroscopy. Further, we observe THz pulse shortening and increase of the group refractive index at high field strengths.......We demonstrate saturable absorber behavior of n-type semiconductors in the THz frequency range using nonlinear THz spectroscopy. Further, we observe THz pulse shortening and increase of the group refractive index at high field strengths....

  17. Minimum K_2,3-saturated Graphs

    CERN Document Server

    Chen, Ya-Chen

    2010-01-01

    A graph is K_{2,3}-saturated if it has no subgraph isomorphic to K_{2,3}, but does contain a K_{2,3} after the addition of any new edge. We prove that the minimum number of edges in a K_{2,3}-saturated graph on n >= 5 vertices is sat(n, K_{2,3}) = 2n - 3.

  18. Pulse shape discrimination in non-aromatic plastics

    International Nuclear Information System (INIS)

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

  19. Dwell-time related saturation of phase coherence in ballistic quantum dots

    Science.gov (United States)

    Hackens, B.; Faniel, S.; Gustin, C.; Wallart, X.; Bollaert, S.; Cappy, A.; Bayot, V.

    2006-08-01

    We present our experimental investigations on the low-temperature ( T) saturation of the electron phase coherence time τ φ in open ballistic quantum dots fabricated from InGaAs/InAlAs heterostructures. At high temperature, we observe that τ φ= aT- p, with 2/3saturates in all our samples. The condition for the occurrence of saturation is found to be τ φ, sat= τd, where τ φ, sat is the saturated coherence time and τd is the dwell time. We discuss possible interpretations for this observation.

  20. Graphite Oxide and Aromatic Amines : Size Matters

    NARCIS (Netherlands)

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

    2015-01-01

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

  1. International congress on aromatic and medicinal plants

    International Nuclear Information System (INIS)

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

  2. Activity relationships for aromatic crown ethers

    CERN Document Server

    Wilson, M J

    1998-01-01

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

  3. Comments on Coulomb pairing in aromatic hydrocarbons

    CERN Document Server

    Huber, D L

    2013-01-01

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

  4. Aromatic hydrocarbons of petroleum from the Sergipe-Alagoas basin; Hidrocarbonetos aromaticos de petroleos da Bacia Sergipe-Alagoas

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Daniel I. de; Lima, Sandovanio F. de; Silva, Valeria W.; Sant' Ana, Antonio E.G.; Reboucas, Lucia M.C. [Alagoas Univ., Maceio, AL (Brazil). Dept. de Quimica]. E-mail: lmcr@qui.ufal.br

    2003-07-01

    Analysis using capillary gas chromatography-mass spectrometry (GC-MS) were carried out on the aromatic and saturated fraction from 4 crude oil samples from Sergipe-Alagoas basin, Brazil. On the basis of GC/MS analysis saturated fraction (n-alkanes and the isoprenoid alkanes pristane and phytane) it is assumed that 1 oil was biodegraded and 3 oils were non biodegraded. Variations in the distributions of trimethyl naphthalenes (TMNs), tetramethyl naphthalenes (TeMNs) and pentamethyl naphthalenes (PMNs) were studied in the 4 crude oils. The percentage of phenanthrene (P), in the tricyclic aromatic fractions, was the same in 3 of the 4 oils studied. Their maturation is assessed on the basis of the distribution and abundance of tricyclic aromatic hydrocarbons that are more resistant to biodegradation than alkane-type biological markers. These crude oils may be classified, on the basis of the maturation parameter MPI 3, as moderately mature. The occurrence of two series of tri aromatic steranes, m/z 231 and m/z 245, were also studied. (author)

  5. Aromatic amines sources, environmental impact and remediation

    OpenAIRE

    Pereira, Luciana; Mondal, P. K.; Alves, M. M.

    2015-01-01

    Aromatic amines are widely used industrial chemicals as their major sources in the environment include several chemical industry sectors such as oil refining, synthetic polymers, dyes, adhesives, rubbers, perfume, pharmaceuticals, pesticides and explosives. They result also from diesel exhaust, combustion of wood chips and rubber and tobacco smoke. Some types of aromatic amines are generated during cooking, special grilled meat and fish, as well. The intensive use and production of these comp...

  6. Aromaticity influencing the thermostability of micellar dispersions

    Energy Technology Data Exchange (ETDEWEB)

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

    1971-05-11

    A hydrocarbon, having sufficient aromaticity to obtain a stable micellar dispersion at the temperature of the formation, is mixed with a surfactant and aqueous medium for injection into the formation to recover crude oil. Higher reservoir temperatures require a greater degree of aromaticity in the hydrocarbon component of the micellar dispersion. This patent is a continuation of U.S. Patent Number 3,495,660 (item No. 118).

  7. Nonchemical weeding of medicinal and aromatic plants

    OpenAIRE

    Carrubba, Alessandra; Militello, Marcello

    2013-01-01

    Medicinal and aromatic plants are major crops of domestic and industrial interest. Medicinal and aromatic plants are increasingly organically grown to enhance profitability. However, the presence of weeds may lead to a decrease in both yield and quality. Therefore, nonchemical methods of weed control are needed. In this study, mechanical weeding, flaming, stale seedbed, and biodegradable mulch were tested from 2003/2004 to 2006/2007 on coriander, fennel, and psyllium. Biomass and seed yield w...

  8. Chemotaxis of Azospirillum Species to Aromatic Compounds

    OpenAIRE

    Lopez-de-Victoria, Geralyne; Lovell, Charles R.

    1993-01-01

    Chemotaxis of Azospirillum lipoferum Sp 59b and Azospirillum brasilense Sp 7 and Sp CD to malate and to the aromatic substrates benzoate, protocatechuate, 4-hydroxybenzoate, and catechol was assayed by the capillary method and direct cell counts. A. lipoferum required induction by growth on 4-hydroxybenzoate for positive chemotaxis to this compound. Chemotaxis of Azospirillum spp. to all other substrates did not require induction. Maximum chemotactic responses for most aromatic compounds occu...

  9. SATURATED ZONE IN-SITU TESTING

    Energy Technology Data Exchange (ETDEWEB)

    P.W. REIMUS

    2004-11-08

    The purpose of this scientific analysis is to document the results and interpretations of field experiments that test and validate conceptual flow and radionuclide transport models in the saturated zone (SZ) near Yucca Mountain, Nevada. The test interpretations provide estimates of flow and transport parameters used in the development of parameter distributions for total system performance assessment (TSPA) calculations. These parameter distributions are documented in ''Site-Scale Saturated Zone Flow Model (BSC 2004 [DIRS 170037]), Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]), Saturated Zone Colloid Transport (BSC 2004 [DIRS 170006]), and ''Saturated Zone Flow and Transport Model Abstraction'' (BSC 2004 [DIRS 170042]). Specifically, this scientific analysis contributes the following to the assessment of the capability of the SZ to serve as part of a natural barrier for waste isolation for the Yucca Mountain repository system: (1) The bases for selection of conceptual flow and transport models in the saturated volcanics and the saturated alluvium located near Yucca Mountain. (2) Results and interpretations of hydraulic and tracer tests conducted in saturated fractured volcanics at the C-wells complex near Yucca Mountain. The test interpretations include estimates of hydraulic conductivities, anisotropy in hydraulic conductivity, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, matrix diffusion coefficients, fracture apertures, and colloid transport parameters. (3) Results and interpretations of hydraulic and tracer tests conducted in saturated alluvium at the Alluvial Testing Complex (ATC) located at the southwestern corner of the Nevada Test Site (NTS). The test interpretations include estimates of hydraulic conductivities, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass

  10. SATURATED ZONE IN-SITU TESTING

    International Nuclear Information System (INIS)

    The purpose of this scientific analysis is to document the results and interpretations of field experiments that test and validate conceptual flow and radionuclide transport models in the saturated zone (SZ) near Yucca Mountain, Nevada. The test interpretations provide estimates of flow and transport parameters used in the development of parameter distributions for total system performance assessment (TSPA) calculations. These parameter distributions are documented in ''Site-Scale Saturated Zone Flow Model (BSC 2004 [DIRS 170037]), Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]), Saturated Zone Colloid Transport (BSC 2004 [DIRS 170006]), and ''Saturated Zone Flow and Transport Model Abstraction'' (BSC 2004 [DIRS 170042]). Specifically, this scientific analysis contributes the following to the assessment of the capability of the SZ to serve as part of a natural barrier for waste isolation for the Yucca Mountain repository system: (1) The bases for selection of conceptual flow and transport models in the saturated volcanics and the saturated alluvium located near Yucca Mountain. (2) Results and interpretations of hydraulic and tracer tests conducted in saturated fractured volcanics at the C-wells complex near Yucca Mountain. The test interpretations include estimates of hydraulic conductivities, anisotropy in hydraulic conductivity, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, matrix diffusion coefficients, fracture apertures, and colloid transport parameters. (3) Results and interpretations of hydraulic and tracer tests conducted in saturated alluvium at the Alluvial Testing Complex (ATC) located at the southwestern corner of the Nevada Test Site (NTS). The test interpretations include estimates of hydraulic conductivities, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, and colloid

  11. Polynuclear aromatic hydrocarbons for fullerene synthesis in flames

    Science.gov (United States)

    Alford, J. Michael; Diener, Michael D.

    2006-12-19

    This invention provides improved methods for combustion synthesis of carbon nanomaterials, including fullerenes, employing multiple-ring aromatic hydrocarbon fuels selected for high carbon conversion to extractable fullerenes. The multiple-ring aromatic hydrocarbon fuels include those that contain polynuclear aromatic hydrocarbons. More specifically, multiple-ring aromatic hydrocarbon fuels contain a substantial amount of indene, methylnapthalenes or mixtures thereof. Coal tar and petroleum distillate fractions provide low cost hydrocarbon fuels containing polynuclear aromatic hydrocarbons, including without limitation, indene, methylnapthalenes or mixtures thereof.

  12. Hydraulic Fracturing in Saturated Cohesionless Materials

    Science.gov (United States)

    Germanovich, L. N.; Hurt, R. S.; Huang, H.

    2007-12-01

    Based on the developed experimental techniques, hydraulic fracturing in particulate materials has been directly observed in the laboratory. As a result, we suggested several mechanisms of hydraulic fracturing in particulate materials and determined relevant scaling relationships (e.g., the interplay between elastic and plastic processes). While the ongoing work is likely to change at least some conclusions, it is important that the results reported in this work appear to form the framework for modeling and, perhaps, even for (qualitative) interpretation of field data. The observed fracture geometry and the measured pressure injection curves suggest that hydraulic fracturing occurs in soft sediments in the following sequence: (i) cavity expansion, (ii) fracture front initiation, and (iii) propagation of the developed fracture. Our experiments show that liquid can indeed propagate as a crack-like feature when injected into cohesionless saturated materials. Laboratory observations suggest that at the initial stage, the cavity expansion process ends with fracture initiation. Sometimes, the growing fracture resembles penetration of one movable material into another less movable material, which may be a manifestation of the Taylor-like instability. An important conclusion of our work is that all parts of the cohesionless particulate material (including the tip zone of hydraulic fracture) are likely to be in compression. The compressive stress state is an important characteristic of hydraulic fracturing in particulate materials with low, or no, cohesion (such as were used in our experiments). At present, two kinematic mechanisms of fracture propagation, consistent with the compressive stress regime, can be offered. The first mechanism is based on shear bands propagating ahead of the tip of an open fracture. The second is based on the tensile strain ahead of the fracture tip and reduction of the effective stresses to zero within the leak-off zone. Additionally, an

  13. Planetary cratering 2: Studies of saturation equilibrium

    Science.gov (United States)

    Hartmann, William K.; Gaskell, Robert W.

    1997-01-01

    A realistic computer model has been developed to display images of imaginary cratered surfaces, taking into account empirically measured input size distributions of primary and secondary craters, ejecta blanket morphology including feathering with distance, obliteration due to ejecta from outside the imaged area, lighting effects, etc. The model allows us to track surface evolution of morphology as new craters are added. Using the model as well as lunar photos, we have studied the approach to saturation equilibrium (defined as a condition when no further proportionate increase in crater density occurs as input cratering increases). We find that an identifiable saturation equilibrium occurs close to a level previously identified for this state (Hartmann 1984), typically fluctuating around a crater density from about 0.4 to 2 times that level. This result is fairly robust vis-a-vis the range of model parameters we have chosen. Flooding, basin ejecta blankets, and other obliterative effects can introduce structure and oscillations within this range, even after saturation equilibrium is achieved. These findings may constrain or revise certain earlier interpretations of satellite and planet surface evolution and impactor populations which were predicated on the assumed absence of saturation equilibrium. In our fourth experimental run, we found that suppression of "sandblasting" by sub-resolution impacts allows the smallest secondaries to rise above the saturation equilibrium line, a result that might be relevant to a similar situation on Gaspra and perhaps some other asteroids.

  14. Locally Controlled Deeply Saturated Fiber Optic Parametric Amplifiers

    Science.gov (United States)

    Nissim, Ron Reuven

    A new class of highly efficient Optical Parametric Amplifiers (OPA) is explored in this dissertation, which have the potential to reduce the power requirement on the pump and enable new functionalities. This originates from the simple notion that figure of merit (FoM) of an OPA is proportional to the product of the pump power and amplifier's length and nonlinearity. Silica fibers have been developed for over five decades and offer unparalleled transparency. By merely extending the fiber, i.e. the amplifier's length, a high FoM amplifier can be formed while keeping the pump at a moderate, sub-Watt power level. Unfortunately, optical fibers are inherently non-uniform. Their core size fluctuates along the fiber on a nanometer scale which is on the order of the fiber's molecular constituents. It is currently established that the performance of a fiber-based OPA (FOPA) is dictated by its stochastic nature. In fact, given a moderate pump power level, the highly efficient OPA will be required to maintain a strict phase matching condition across hundreds of meters. Facing this challenge, this dissertation focuses on a locally-controlled, high FoM FOPA. A high FoM FOPA operates in the deeply saturated regime in which a weak signal saturates the amplifier and depletes the pump power, effectively generating an inverse response of the pump output power to the signal input power. Given FOPAs' inhomogeneous nature, the performance limit of deeply saturated FOPAs is studied. So far, FOPAs have been commonly treated as a uniform entity; however, this study discovers unique features of the system which originate from and are strongly influenced by the fiber's inhomogeneous nature. One major example is the non-reciprocal response of deeply saturated FOPAs. It was found that deeply saturated FOPAs perform very highly, as the pump can respond to a rapidly varying (sub-THz) weak (sub-muW) signal. This is a novel method which obtained orders of magnitude improvement over current

  15. Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle

    2006-04-30

    During this last period of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we finalized integration of rock physics, well log analysis, seismic processing, and forward modeling techniques. Most of the last quarter was spent combining the results from the principal investigators and come to some final conclusions about the project. Also much of the effort was directed towards technology transfer through the Direct Hydrocarbon Indicators mini-symposium at UH and through publications. As a result we have: (1) Tested a new method to directly invert reservoir properties, water saturation, Sw, and porosity from seismic AVO attributes; (2) Constrained the seismic response based on fluid and rock property correlations; (3) Reprocessed seismic data from Ursa field; (4) Compared thin layer property distributions and averaging on AVO response; (5) Related pressures and sorting effects on porosity and their influence on DHI's; (6) Examined and compared gas saturation effects for deep and shallow reservoirs; (7) Performed forward modeling using geobodies from deepwater outcrops; (8) Documented velocities for deepwater sediments; (9) Continued incorporating outcrop descriptive models in seismic forward models; (10) Held an open DHI symposium to present the final results of the project; (11) Relations between Sw, porosity, and AVO attributes; (12) Models of Complex, Layered Reservoirs; and (14) Technology transfer Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and

  16. An overview of the AROMAT campaigns

    Science.gov (United States)

    Merlaud, Alexis; Dekemper, Emmanuel; Van Roozendael, Michel; Constantin, Daniel; Georgescu, Lucian; Meier, Andreas; Richter, Andreas; Den Hoed, Mirjam; Allaart, Marc; Boscornea, Andreea; Vajaiac, Sorin; Bellegante, Livio; Nemuc, Anca; Nicolae, Doina; Shaifangar, Reza; Dörner, Steffen; Wagner, Thomas; Stebel, Kerstin; Schuettemeyer, Dirk

    2016-04-01

    The Airborne ROmanian Measurements of Aerosols and Trace gases (AROMAT) campaign and its follow-up AROMAT-2 were held in September 2014 and August 2015, respectively. Both campaigns focused on two geophysical targets: the city of Bucharest and the large power plants of the Jiu Valley, which are located in a rural area 170 km West of Bucharest. These two areas are complementary in terms of emitted chemical species and their spatial distributions. The objectives of the AROMAT campaigns were (i) to test recently developed airborne observation systems dedicated to air quality satellite validation studies such as the AirMAP imaging DOAS system (University of Bremen), the NO2 sonde (KNMI), and the compact SWING whiskbroom imager (BIRA), and (ii) to prepare the validation programme of the future Atmospheric Sentinels, starting with Sentinel-5 Precursor (S5P) to be launched in early summer 2016. We present results from the different airborne instrumentations and from coincident ground-based measurements (lidar, in-situ, and mobile DOAS systems) performed during both campaigns. The AROMAT dataset addresses several of the mandatory products of TROPOMI/S5P, in particular NO2 and SO2 (horizontal distribution and profile from aircraft, plume image with ground-based SO2 and NO2 cameras, transects with mobile DOAS, in-situ), H2CO (mobile MAX-DOAS), and aerosols (lidar, airborne FUBISS-ASA2 sun-photometer, and aircraft in-situ). We investigate the information content of the AROMAT dataset for satellite validation studies based on co-located OMI and GOME-2 data, and simulations of TROPOMI measurements. The experience gained during AROMAT and AROMAT-2 will be used in support of a large-scale TROPOMI/S5P validation campaign in Romania scheduled for summer 2017.

  17. Lipid order, saturation and surface property relationships: a study of human meibum saturation.

    Science.gov (United States)

    Mudgil, Poonam; Borchman, Douglas; Yappert, Marta C; Duran, Diana; Cox, Gregory W; Smith, Ryan J; Bhola, Rahul; Dennis, Gary R; Whitehall, John S

    2013-11-01

    Tear film stability decreases with age however the cause(s) of the instability are speculative. Perhaps the more saturated meibum from infants may contribute to tear film stability. The meibum lipid phase transition temperature and lipid hydrocarbon chain order at physiological temperature (33 °C) decrease with increasing age. It is reasonable that stronger lipid-lipid interactions could stabilize the tear film since these interactions must be broken for tear break up to occur. In this study, meibum from a pool of adult donors was saturated catalytically. The influence of saturation on meibum hydrocarbon chain order was determined by infrared spectroscopy. Meibum is in an anhydrous state in the meibomian glands and on the surface of the eyelid. The influence of saturation on the surface properties of meibum was determined using Langmuir trough technology. Saturation of native human meibum did not change the minimum or maximum values of hydrocarbon chain order so at temperatures far above or below the phase transition of human meibum, saturation does not play a role in ordering or disordering the lipid hydrocarbon chains. Saturation did increase the phase transition temperature in human meibum by over 20 °C, a relatively high amount. Surface pressure-area studies showing the late take off and higher maximum surface pressure of saturated meibum compared to native meibum suggest that the saturated meibum film is quite molecularly ordered (stiff molecular arrangement) and elastic (molecules are able to rearrange during compression and expansion) compared with native meibum films which are more fluid agreeing with the infrared spectroscopic results of this study. In saturated meibum, the formation of compacted ordered islands of lipids above the surfactant layer would be expected to decrease the rate of evaporation compared to fluid and more loosely packed native meibum. Higher surface pressure observed with films of saturated meibum compared to native meibum

  18. Dilatant hardening of fluid-saturated sandstone

    Science.gov (United States)

    Makhnenko, Roman Y.; Labuz, Joseph F.

    2015-02-01

    The presence of pore fluid in rock affects both the elastic and inelastic deformation processes, yet laboratory testing is typically performed on dry material even though in situ the rock is often saturated. Techniques were developed for testing fluid-saturated porous rock under the limiting conditions of drained, undrained, and unjacketed response. Confined compression experiments, both conventional triaxial and plane strain, were performed on water-saturated Berea sandstone to investigate poroelastic and inelastic behavior. Measured drained response was used to calibrate an elasto-plastic constitutive model that predicts undrained inelastic deformation. The experimental data show good agreement with the model: dilatant hardening in undrained triaxial and plane strain compression tests under constant mean stress was predicted and observed.

  19. Site-Scale Saturated Zone Flow Model

    Energy Technology Data Exchange (ETDEWEB)

    G. Zyvoloski

    2003-12-17

    The purpose of this model report is to document the components of the site-scale saturated-zone flow model at Yucca Mountain, Nevada, in accordance with administrative procedure (AP)-SIII.lOQ, ''Models''. This report provides validation and confidence in the flow model that was developed for site recommendation (SR) and will be used to provide flow fields in support of the Total Systems Performance Assessment (TSPA) for the License Application. The output from this report provides the flow model used in the ''Site-Scale Saturated Zone Transport'', MDL-NBS-HS-000010 Rev 01 (BSC 2003 [162419]). The Site-Scale Saturated Zone Transport model then provides output to the SZ Transport Abstraction Model (BSC 2003 [164870]). In particular, the output from the SZ site-scale flow model is used to simulate the groundwater flow pathways and radionuclide transport to the accessible environment for use in the TSPA calculations. Since the development and calibration of the saturated-zone flow model, more data have been gathered for use in model validation and confidence building, including new water-level data from Nye County wells, single- and multiple-well hydraulic testing data, and new hydrochemistry data. In addition, a new hydrogeologic framework model (HFM), which incorporates Nye County wells lithology, also provides geologic data for corroboration and confidence in the flow model. The intended use of this work is to provide a flow model that generates flow fields to simulate radionuclide transport in saturated porous rock and alluvium under natural or forced gradient flow conditions. The flow model simulations are completed using the three-dimensional (3-D), finite-element, flow, heat, and transport computer code, FEHM Version (V) 2.20 (software tracking number (STN): 10086-2.20-00; LANL 2003 [161725]). Concurrently, process-level transport model and methodology for calculating radionuclide transport in the saturated zone at Yucca

  20. Oxygen Saturation Targeting and Bronchopulmonary Dysplasia.

    Science.gov (United States)

    Darlow, Brian A; Morley, Colin J

    2015-12-01

    Oxygen saturation targeting is widely used in neonatal intensive care, but the optimal target range in very preterm infants has been uncertain and is the subject of recent debate and research. This review briefly discusses the technology of oxygen monitoring and the role of oxygen toxicity in preterm infants. The background to the recent trials of oxygen saturation targeting in acute and continuing care of very preterm infants is reviewed, and the findings and implications of the recent trials, particularly with respect to bronchopulmonary dysplasia, are discussed. PMID:26593080

  1. Saturated Zone Colloid-Facilitated Transport

    Energy Technology Data Exchange (ETDEWEB)

    A. Wolfsberg; P. Reimus

    2001-12-18

    The purpose of the Saturated Zone Colloid-Facilitated Transport Analysis and Modeling Report (AMR), as outlined in its Work Direction and Planning Document (CRWMS M&O 1999a), is to provide retardation factors for colloids with irreversibly-attached radionuclides, such as plutonium, in the saturated zone (SZ) between their point of entrance from the unsaturated zone (UZ) and downgradient compliance points. Although it is not exclusive to any particular radionuclide release scenario, this AMR especially addresses those scenarios pertaining to evidence from waste degradation experiments, which indicate that plutonium and perhaps other radionuclides may be irreversibly attached to colloids. This report establishes the requirements and elements of the design of a methodology for calculating colloid transport in the saturated zone at Yucca Mountain. In previous Total Systems Performance Assessment (TSPA) analyses, radionuclide-bearing colloids were assumed to be unretarded in their migration. Field experiments in fractured tuff at Yucca Mountain and in porous media at other sites indicate that colloids may, in fact, experience retardation relative to the mean pore-water velocity, suggesting that contaminants associated with colloids should also experience some retardation. Therefore, this analysis incorporates field data where available and a theoretical framework when site-specific data are not available for estimating plausible ranges of retardation factors in both saturated fractured tuff and saturated alluvium. The distribution of retardation factors for tuff and alluvium are developed in a form consistent with the Performance Assessment (PA) analysis framework for simulating radionuclide transport in the saturated zone. To improve on the work performed so far for the saturated-zone flow and transport modeling, concerted effort has been made in quantifying colloid retardation factors in both fractured tuff and alluvium. The fractured tuff analysis used recent data

  2. High speed drying of saturated steam

    International Nuclear Information System (INIS)

    This paper describes the development of the drying process for the saturated steam used in the PWR nuclear plant turbines in order to prevent negative effects of water on turbine efficiency, maintenance costs and equipment lifetime. The high speed drying concept is based on rotating the incoming saturated steam in order to separate water which is more denser than the steam; the water film is then extracted through an annular slot. A multicellular modular equipment has been tested. Applications on high and low pressure extraction of various PWR plants are described (Bugey, Loviisa)

  3. Site-Scale Saturated Zone Flow Model

    International Nuclear Information System (INIS)

    The purpose of this model report is to document the components of the site-scale saturated-zone flow model at Yucca Mountain, Nevada, in accordance with administrative procedure (AP)-SIII.lOQ, ''Models''. This report provides validation and confidence in the flow model that was developed for site recommendation (SR) and will be used to provide flow fields in support of the Total Systems Performance Assessment (TSPA) for the License Application. The output from this report provides the flow model used in the ''Site-Scale Saturated Zone Transport'', MDL-NBS-HS-000010 Rev 01 (BSC 2003 [162419]). The Site-Scale Saturated Zone Transport model then provides output to the SZ Transport Abstraction Model (BSC 2003 [164870]). In particular, the output from the SZ site-scale flow model is used to simulate the groundwater flow pathways and radionuclide transport to the accessible environment for use in the TSPA calculations. Since the development and calibration of the saturated-zone flow model, more data have been gathered for use in model validation and confidence building, including new water-level data from Nye County wells, single- and multiple-well hydraulic testing data, and new hydrochemistry data. In addition, a new hydrogeologic framework model (HFM), which incorporates Nye County wells lithology, also provides geologic data for corroboration and confidence in the flow model. The intended use of this work is to provide a flow model that generates flow fields to simulate radionuclide transport in saturated porous rock and alluvium under natural or forced gradient flow conditions. The flow model simulations are completed using the three-dimensional (3-D), finite-element, flow, heat, and transport computer code, FEHM Version (V) 2.20 (software tracking number (STN): 10086-2.20-00; LANL 2003 [161725]). Concurrently, process-level transport model and methodology for calculating radionuclide transport in the saturated zone at Yucca Mountain using FEHM V 2.20 are being

  4. Beyond nonlinear saturation of backward Raman amplifiers

    Science.gov (United States)

    Barth, Ido; Toroker, Zeev; Balakin, Alexey A.; Fisch, Nathaniel J.

    2016-06-01

    Backward Raman amplification is limited by relativistic nonlinear dephasing resulting in saturation of the leading spike of the amplified pulse. Pump detuning is employed to mitigate the relativistic phase mismatch and to overcome the associated saturation. The amplified pulse can then be reshaped into a monospike pulse with little precursory power ahead of it, with the maximum intensity increasing by a factor of two. This detuning can be employed advantageously both in regimes where the group velocity dispersion is unimportant and where the dispersion is important but small.

  5. Supercritical water oxidation for destruction of polycyclic aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Polycyclic aromatic hydrocarbons (PAHs) represent a large class of hydrocarbons that are considered hazardous to the environment. Large amount of PAHs have been dumped onto open ground in cases such as Town gas sites. These sites represent a major environmental liability due to the difficulty in removing them by conventional methods and the large amount of sites, more than 2,000. Supercritical water oxidation offers a unique method of both removing the contaminates and destroying them in a single stage processing step. The process utilizes the single phase mixture of water and oxygen at supercritical water conditions. This allows for the PAHs to be extracted and destroyed simultaneously. The reaction produces an effluent stream rich in carbon dioxide and water. Town gas soil containing 3.37 wt% contamination was ultra-cleaned in a 1-liter pilot plant to an environmentally acceptable level of less than 200 ppm

  6. Silicone elastomers with aromatic voltage stabilizers

    DEFF Research Database (Denmark)

    A Razak, Aliff Hisyam; Skov, Anne Ladegaard

    insulation cables.3–5 As an alternative to utilise additives as voltage stabilizers, grafting aromatic compounds to silicone backbones may overcome the common problem of insolubility of the aromatic voltage stabilizer in the silicone elastomers due to phase separation. Preventing phase separation during...... via hydrosilylation by a vinyl-functional crosslinker. The mechanism of electron-trapping by aromatic compounds grafted to silicone backbones in a crosslinked PDMS is illustrated in Fig. 1. The electrical breakdown strength, the storage modulus and the loss modulus of the elastomer were investigated...... attached to the silicone backbone. The dielectric relative permittivity of PDMS-PPMS copolymers remained between 2 to 3 with low conductivity and low dielectric loss as well as high storage moduli with low viscous loss, thereby maintaining the electro-mechanical integrity of the elastomer....

  7. Chemotaxis of Azospirillum species to aromatic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-de-Victoria, G.; Lovell, C.R. (Univ. of South Carolina, Columbia, SC (United States))

    1993-09-01

    Azospirillum sspeciesare free-living nitrogen fixing bacteria commonly found in soils and in association with plant roots, including important agricultural crops. Rhizosphere colonization my Azospirillum species has been shown to stimulate growth of a variety of plant species. Chemotaxis is one of the properties which may contribute to survival, rhizosphere colonization and the initiation of mutualistic interactions by Azospirillum species. This study evaluates the chemotactic responses of three Azospirillum stains to a variety of aromatic compounds:benzoate, catechol, 4-HB, and PCA. Results indicate that the same aromatic substance can elicit different chemotactic responses from different Azospirillum species, and that Azospirillum can detect aromatic substrates at concentrations similar to those they encounter naturally. 36 refs., 1 fig., 6 tabs.

  8. Boundary conditions for porous solids saturated with viscous fluid

    Institute of Scientific and Technical Information of China (English)

    M.D.Sharma

    2009-01-01

    Boundary conditions are derived to represent the continuity requirements at the boundaries of a porous solid saturated with viscous fluid.They are derived from the physically grounded principles with a mathematical check on the conservation of energy.The poroelastic solid is a dissipative one for the presence of viscosity in the interstitial fluid.The dissipative stresses due to the viscosity of pore-fluid are well represented in the boundary conditions.The unequal particle motions of two constituents of porous aggregate at a boundary between two solids are explained in terms of the drainage of pore-fluid leading to imperfect bonding.A mathematical model is derived for the partial connection of surface pores at the porous-porous interface.At this interface,the loose-contact slipping and partial pore opening/connection may dissipate a part of strain energy.A numerical example shows that,at the interface between water and oil-saturated sandstone,the modified boundary conditions do affect the energies of the waves refracting into the isotropic porous medium.

  9. Mechanism of tetralin ring opening and contraction over bifunctional Ir/SiO₂-Al₂O₃ Catalysts.

    Science.gov (United States)

    Piccolo, Laurent; Nassreddine, Salim; Toussaint, Guy; Geantet, Christophe

    2012-09-01

    The development of cleaner fuels from conventional resources requires the finding of new hydrotreatment processes able to improve the combustion performances of fuels and limit undesirable emissions. In the context of gas oil upgrading by selective ring opening, we have investigated the hydroconversion of tetralin over iridium nanoparticles supported on amorphous silica-alumina. The conversion of tetralin leads to hydrogenation, ring-contraction, and ring-opening products. The selectivity to ring-opening/-contraction products (ROCPs) increases linearly with the acid-metal site ratio and can be tuned by modifying the metal loading, the metal nanoparticle size, or the support composition. From the combination of catalytic tests at variable conversion and the products identification by two-dimensional gas chromatography, a mechanistic reaction scheme has been established. Aromatic ROCPs are formed through purely acidic steps, whereas the formation of saturated ROCPs mostly involves bifunctional reaction steps. Iridium-catalyzed hydrogenolysis appears to be a minor pathway with respect to iridium-catalyzed hydrogenation and Brønsted acid catalyzed isomerization. PMID:22949005

  10. CALCULATING THE PH OF CALCIUM CARBONATE SATURATION

    Science.gov (United States)

    Two new expressions for the pH of saturation (pH subs) were derived. One is a simplified equation developed from an aqueous carbonate equilibrium system in which correction for ionic strength was considered. The other is a more accurate quadratic formula that involves computerize...

  11. Nasal pulse oximetry overestimates oxygen saturation

    DEFF Research Database (Denmark)

    Rosenberg, J; Pedersen, M H

    1990-01-01

    Ten surgical patients were monitored with nasal and finger pulse oximetry (Nellcor N-200) for five study periods with alternating mouth and nasal breathing and switching of cables and sensors. Nasal pulse oximetry was found to overestimate arterial oxygen saturation by 4.7 (SD 1.4%) (bias and...

  12. On the saturation of astrophysical dynamos

    DEFF Research Database (Denmark)

    Dorch, Bertil; Archontis, Vasilis

    2004-01-01

    In the context of astrophysical dynamos we illustrate that the no-cosines flow, with zero mean helicity, can drive fast dynamo action and we study the dynamo's mode of operation during both the linear and non-linear saturation regimes. It turns out that in addition to a high growth rate in the...

  13. Electric pulse generator with a saturable inductance

    International Nuclear Information System (INIS)

    Power supply of induction accelerators is obtained with a pulse generator comprising a coaxial line shaping the pulses and magnetic compression means feeding this line with a capacitor and a saturable inductance, inside the line. A conductor is connected to the end of the inductance and to the median part of the internal electrode and a magnetic commutator discharging the line

  14. Saturation Advertising and the Repetition Effect.

    Science.gov (United States)

    Baddeley, A. D.; Bekerian, D. A.

    1980-01-01

    An investigation of a saturation advertising campaign to acquaint the public with changes in radio wavelengths showed that repeated presentation of material does not lead to learning unless appropriate encoding occurs. Such encoding will occur when subjects are allowed to use previously acquired learning strategies. (PMJ)

  15. Two-beam interaction in saturable media

    DEFF Research Database (Denmark)

    Schjødt-Eriksen, Jens; Schmidt, Michel R.; Juul Rasmussen, Jens;

    1998-01-01

    The dynamics of two coupled soliton solutions of the nonlinear Schrodinger equation with a saturable nonlinearity is investigated It is shown by means of a variational method and by direct numerical calculations that two well-separated solitons can orbit around each other, if their initial veloci...

  16. Saturated gravity wave spectra measured with balloons in Mendoza (Argentina)

    Science.gov (United States)

    de la Torre, A.; Giraldez, A.; Alexander, P.

    1994-09-01

    Spectral results from a sounding of temperature and wind velocity between 11.9 and 23.1 km performed with an open type stratospheric balloon near the Andes Mountains, are reported. The use of this kind of balloons and high performance instruments, allowed to attain better spatial resolution (around 2.5 meters during the descent) than previous results and other sounding techniques. This high resolution permitted to study the complete interval of altitude data in three consecutive subintervals (below, around and above the tropopause). Each of these subintervals shows different saturation characteristics. Some differences have been found with the general pattern of power spectral densities reported by different theories. A large amplitude wave of around 1.8 km and possibly originated in the mountain relief, is clearly observed in the temperature, vertical and shear wind velocity components.

  17. Dibenzoheptazethrene isomers with different biradical characters: An exercise of clar's aromatic sextet rule in singlet biradicaloids

    KAUST Repository

    Sun, Zhe

    2013-12-04

    Clar\\'s aromatic sextet rule has been widely used for the prediction of the reactivity and stability of polycyclic aromatic hydrocarbons with a closed-shell electronic configuration. Recent advances in open-shell biradicaloids have shown that the number of aromatic sextet rings plays an important role in determination of their ground states. In order to test the validity of this rule in singlet biradicaloids, the two soluble and stable dibenzoheptazethrene isomers DBHZ1 and DBHZ2 were prepared by different synthetic approaches and isolated in crystalline form. These two molecules have different numbers of aromatic sextet rings in their respective biradical resonance forms and thus are expected to exhibit varied singlet biradical character. This assumption was verified by different experimental methods, including nuclear magnetic resonance (NMR), electron spin resonance (ESR), superconducting quantum interference device (SQUID), steady-state and transient absorption spectroscopy (TA), and X-ray crystallographic analysis, assisted by unrestricted symmetry-broken density functional theory (DFT) calculations. DBHZ2, with more aromatic sextet rings in the biradical form, was demonstrated to possess greater biradical character than DBHZ1; as a result, DBHZ2 exhibited an intense one-photon absorption (OPA) in the near-infrared region (λabs max = 804 nm) and a large two-photon absorption (TPA) cross-section (σ(2)max = 2800 GM at 1600 nm). This investigation together with previous studies indicates that Clar\\'s aromatic sextet rule can be further extended to the singlet biradicaloids to predict their ground states and singlet biradical characters. © 2013 American Chemical Society.

  18. Production of aromatics from di- and polyoxygenates

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Taylor; Blank, Brian; Jones, Casey; Woods, Elizabeth; Cortright, Randy

    2016-08-02

    Methods, catalysts, and reactor systems for producing in high yield aromatic chemicals and liquid fuels from a mixture of oxygenates comprising di- and polyoxygenates are disclosed. Also disclosed are methods, catalysts, and reactor systems for producing aromatic chemicals and liquid fuels from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like; and methods, catalysts, and reactor systems for producing the mixture of oxygenates from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like. The disclosed catalysts for preparing the mixture of oxygenates comprise a Ni.sub.nSn.sub.m alloy and a crystalline alumina support.

  19. Electron beam irradiation effects on aromatic polymers

    International Nuclear Information System (INIS)

    Electron irradiation effects on aromatic polymers having various molecular structures were studied to elucidate the following subjects; (1) relation between radiation stability and molecular structure of repeating units, (2) mechanism of deterioration and (3) adaptability to matrix resin for radiation resistant FRP. Results are summarized as follows: (1) An order of radiation stability of units is; imide ring > diphenyl ether, diphenyl ketone > aromatic amide >> bis-phenol A > diphenyl sulphone. (2) Poly (ether-ether-ketone) and most polyimide are crosslinkable but polysulphones and polyarylate are chain degradation type polymers. (3) Newly developed thermoplastic polyimides have possibilities for use as matrix materials in radiation resistant FRP. (author)

  20. Microscopic analysis of saturable absorbers: Semiconductor saturable absorber mirrors versus graphene

    Energy Technology Data Exchange (ETDEWEB)

    Hader, J.; Moloney, J. V. [Nonlinear Control Strategies, Inc., 3542 N. Geronimo Ave., Tucson, Arizona 85705 (United States); College of Optical Sciences, University of Arizona, Tucson, Arizona 85721 (United States); Yang, H.-J.; Scheller, M. [College of Optical Sciences, University of Arizona, Tucson, Arizona 85721 (United States); Koch, S. W. [Department of Physics and Materials Sciences Center, Philipps Universität Marburg, Renthof 5, 35032 Marburg (Germany)

    2016-02-07

    Fully microscopic many-body calculations are used to study the influence of strong sub-picosecond pulses on the carrier distributions and corresponding optical response in saturable absorbers used for mode-locking—semiconductor (quantum well) saturable absorber mirrors (SESAMs) and single layer graphene based saturable absorber mirrors (GSAMs). Unlike in GSAMs, the saturation fluence and recovery time in SESAMs show a strong spectral dependence. While the saturation fluence in the SESAM is minimal at the excitonic bandgap, the optimal recovery time and least pulse distortion due to group delay dispersion are found for excitation higher in the first subband. For excitation near the SESAM bandgap, the saturation fluence is about one tenth of that in the GSAM. At energies above the bandgap, the fluences in both systems become similar. A strong dependence of the saturation fluence on the pulse width in both systems is caused by carrier relaxation during the pulse. The recovery time in graphene is found to be about two to four times faster than that in the SESAMs. The occurrence of negative differential transmission in graphene is shown to be caused by dopant related carriers. In SESAMs, a negative differential transmission is found when exciting below the excitonic resonance where excitation induced dephasing leads to an enhancement of the absorption. Comparisons of the simulation data to the experiment show a very good quantitative agreement.

  1. Dependence of mountain moisture retention on downstream saturation

    CERN Document Server

    November, L J

    2007-01-01

    We derive 1D steady equilibria for partially saturated downslope flow as a solution to the reposed vadose-zone problem. The equilibria are determined by two free parameters: a mean flow and a downstream saturation. Where there is no downstream saturation, a uniform outflow of constant saturation is obtained, but if an isolated zone of excess downstream saturation exists, the upstream flow speed is reduced and saturation increased. The saturated zone produces a capillary head jump that blocks the downward percolation. With a fully saturated downstream zone in medium clay mixtures, flow backs up more than 20 km projected vertically, but with 90% downstream saturation, the back up is reduced to less than a km. The drying of downstream saturated zones with the increased rate of mountain moisture outflow gives a viable quantitative explanation for the mysterious 56% unaccounted drop seen in the output of the southern NM La Luz / Fresnal Watershed at Alamogordo's upstream spring-box diversions.

  2. Fluorescence method for enzyme analysis which couples aromatic amines with aromatic aldehydes

    Science.gov (United States)

    Smith, R.E.; Dolbeare, F.A.

    1980-10-21

    Analysis of proteinases is accomplished using conventional amino acid containing aromatic amine substrates. Aromatic amines such as 4-methoxy-2-naphthylamine (4M2NA), 2-naphthylamine, aminoisophthalic acid dimethyl ester, p-nitroaniline, 4-methoxy-1-aminofluorene and coumarin derivatives resulting from enzymatic hydrolysis of the substrate couples with aromatic aldehydes such as 5-nitrosalicylaldehyde (5-NSA), benzaldehyde and p-nitrobenzaldehyde to produce Schiff-base complexes which are water insoluble. Certain Schiff-base complexes produce a shift from blue to orange-red (visible) fluorescence. Such complexes are useful in the assay of enzymes. No Drawings

  3. Fluorescence method for enzyme analysis which couples aromatic amines with aromatic aldehydes

    Science.gov (United States)

    Smith, Robert E.; Dolbeare, Frank A.

    1979-01-01

    Analysis of proteinases is accomplished using conventional amino acid containing aromatic amine substrates. Aromatic amines such as 4-methoxy-2-naphthylamine (4M2NA), 2-naphthylamine, aminoisophthalic acid dimethyl ester, p-nitroaniline, 5-methoxy-1-aminofluorene and coumarin derivatives resulting from enzymatic hydrolysis of the substrate couples with aromatic aldehydes such as 5-nitrosalicylaldehyde (5-NSA), benzaldehyde and p-nitrobenzaldehyde to produce Schiff-base complexes which are water insoluble. Certain Schiff-base complexes produce a shift from blue to orange-red (visible) fluorescence. Such complexes are useful in the assay of enzymes.

  4. Using X-ray computed tomography to evaluate the initial saturation resulting from different saturation procedures

    DEFF Research Database (Denmark)

    Christensen, Britt Stenhøj Baun; Wildenschild, D; Jensen, K.H.

    2006-01-01

    for saturation. Evaluation of the different enhanced saturation techniques was done with Xray computed tomography (CT) and gravimetrically. The use of CT scanning makes it possible to observe the spatial distribution of wetting and non-wetting phases in the porous medium in a non-destructive way. In...... this case the sample was scanned in 1 mm intervals over the height of the 3.5 cm tall sample, providing detailed information on the performance of the different procedures. Five different combinations of the above mentioned saturation procedures were applied to a disturbed silica sand sample. The...

  5. Fluorescent aromatic sensors and their methods of use

    Science.gov (United States)

    Meador, Michael A. (Inventor); Tyson, Daniel S. (Inventor); Ilan, Ulvi F. (Inventor)

    2012-01-01

    Aromatic molecules that can be used as sensors are described. The aromatic sensors include a polycyclic aromatic hydrocarbon core with a five-membered imide rings fused to the core and at least two pendant aryl groups. The aromatic sensor molecules can detect target analytes or molecular strain as a result of changes in their fluorescence, in many cases with on-off behavior. Aromatic molecules that fluoresce at various frequencies can be prepared by altering the structure of the aromatic core or the substituents attached to it. The aromatic molecules can be used as sensors for various applications such as, for example, the detection of dangerous chemicals, biomedical diagnosis, and the detection of damage or strain in composite materials. Methods of preparing aromatic sensor molecules are also described.

  6. Saturated Zone In-Situ Testing

    International Nuclear Information System (INIS)

    The purpose of this scientific analysis is to document the results and interpretations of field experiments that have been conducted to test and validate conceptual flow and radionuclide transport models in the saturated zone (SZ) near Yucca Mountain. The test interpretations provide estimates of flow and transport parameters that are used in the development of parameter distributions for Total System Performance Assessment (TSPA) calculations. These parameter distributions are documented in the revisions to the SZ flow model report (BSC 2003 [ 162649]), the SZ transport model report (BSC 2003 [ 162419]), the SZ colloid transport report (BSC 2003 [162729]), and the SZ transport model abstraction report (BSC 2003 [1648701]). Specifically, this scientific analysis report provides the following information that contributes to the assessment of the capability of the SZ to serve as a barrier for waste isolation for the Yucca Mountain repository system: (1) The bases for selection of conceptual flow and transport models in the saturated volcanics and the saturated alluvium located near Yucca Mountain. (2) Results and interpretations of hydraulic and tracer tests conducted in saturated fractured volcanics at the C-wells complex near Yucca Mountain. The test interpretations include estimates of hydraulic conductivities, anisotropy in hydraulic conductivity, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, matrix diffusion coefficients, fracture apertures, and colloid transport parameters. (3) Results and interpretations of hydraulic and tracer tests conducted in saturated alluvium at the Alluvium Testing Complex (ATC), which is located at the southwestern corner of the Nevada Test Site (NTS). The test interpretations include estimates of hydraulic conductivities, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, and

  7. Saturated Zone In-Situ Testing

    Energy Technology Data Exchange (ETDEWEB)

    P. W. Reimus; M. J. Umari

    2003-12-23

    The purpose of this scientific analysis is to document the results and interpretations of field experiments that have been conducted to test and validate conceptual flow and radionuclide transport models in the saturated zone (SZ) near Yucca Mountain. The test interpretations provide estimates of flow and transport parameters that are used in the development of parameter distributions for Total System Performance Assessment (TSPA) calculations. These parameter distributions are documented in the revisions to the SZ flow model report (BSC 2003 [ 162649]), the SZ transport model report (BSC 2003 [ 162419]), the SZ colloid transport report (BSC 2003 [162729]), and the SZ transport model abstraction report (BSC 2003 [1648701]). Specifically, this scientific analysis report provides the following information that contributes to the assessment of the capability of the SZ to serve as a barrier for waste isolation for the Yucca Mountain repository system: (1) The bases for selection of conceptual flow and transport models in the saturated volcanics and the saturated alluvium located near Yucca Mountain. (2) Results and interpretations of hydraulic and tracer tests conducted in saturated fractured volcanics at the C-wells complex near Yucca Mountain. The test interpretations include estimates of hydraulic conductivities, anisotropy in hydraulic conductivity, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, matrix diffusion coefficients, fracture apertures, and colloid transport parameters. (3) Results and interpretations of hydraulic and tracer tests conducted in saturated alluvium at the Alluvium Testing Complex (ATC), which is located at the southwestern corner of the Nevada Test Site (NTS). The test interpretations include estimates of hydraulic conductivities, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, and

  8. Polycyclic Aromatic Hydrocarbons as Plausible Prebiotic Membrane Components

    OpenAIRE

    Groen, Joost; Deamer, David W.; Kros, Alexander; Ehrenfreund, Pascale

    2012-01-01

    Aromatic molecules delivered to the young Earth during the heavy bombardment phase in the early history of our solar system were likely to be among the most abundant and stable organic compounds available. The Aromatic World hypothesis suggests that aromatic molecules might function as container elements, energy transduction elements and templating genetic components for early life forms. To investigate the possible role of aromatic molecules as container elements, we incorporated different p...

  9. Electronic Aromaticity Index for Large Rings

    CERN Document Server

    Matito, Eduard

    2015-01-01

    We introduce a new electronic aromaticity index, AV1245, consisting in the average of the 4-center MCI values along the ring that keep a positional relationship of 1,2,4,5. AV1245 measures the extent of transferability of the delocalized electrons between bonds 1-2 and 4-5, which is expected to be large in conjugated circuits and, therefore, in aromatic molecules. A new algorithm for the calculation of MCI for large rings is also introduced and used to produce the data for the calibration of the new aromaticity index. AV1245 does not rely on reference values, does not suffer from large numerical precision errors, and it does not present any limitation on the nature of atoms, the molecular geometry or the level of calculation. It is a size-extensive measure with a small computational cost that grows linearly with the number of ring members. Therefore, it is specially suitable to study the aromaticity of large molecular rings as those occurring in belt-shaped M\\"obius structures or porphyrins.

  10. Extremely long aromatics: Diastereomerically pure [19]helicene

    Czech Academy of Sciences Publication Activity Database

    Nejedlý, Jindřich; Rybáček, Jiří; Stará, Irena G.; Starý, Ivo

    Praha: Czech Chemical Society, 2015. s. 119. [Liblice 2015. Advances in Organic , Bioorganic and Pharmaceutical Chemistry /50./. 06.11.2015-08.11.2015, Olomouc] R&D Projects: GA ČR(CZ) GA14-29667S Institutional support: RVO:61388963 Keywords : helically chiral aromatics * helicenes * [2+2+2] cycloisomerisation Subject RIV: CC - Organic Chemistry

  11. Aromatic cytokinins in micropropagated potato plants

    Czech Academy of Sciences Publication Activity Database

    Baroja, F. E.; Aguirreolea, J.; Martínková, Hana; Hanuš, Jan; Strnad, Miroslav

    2002-01-01

    Roč. 40, č. 3 (2002), s. 217-224. ISSN 0981-9428 R&D Projects: GA MŠk OC 844.10; GA ČR GA301/02/0475 Institutional research plan: CEZ:AV0Z5038910 Keywords : Acclimatization * Aromatic cytokinins * Micropropagation Subject RIV: CE - Biochemistry Impact factor: 1.582, year: 2002

  12. Discovering Chemical Aromaticity Using Fragrant Plants

    Science.gov (United States)

    Schneider, Tanya L.

    2010-01-01

    Introductory organic chemistry is often perceived as inaccessible by students. This article describes a method used to link organic chemistry to everyday experience, asking students to explore whether fragrant molecules are also aromatic in the chemical sense. Students were engaged in this activity, excited about their results, and performed well…

  13. Thermoset/Thermoplastic Aromatic Polyamides for Composites

    Science.gov (United States)

    St. Clair, T. L.; St. Clair, A. K.; Barrick, J. D.; Wolfe, J. F.; Greenwood, T. D.

    1983-01-01

    Aromatic polyamides are processed at relatively low temperature, then heat-treated to attain high softening temperature required when polyamides are used as matrix resins in structural composites. New polyamides are compatable with organic fibers often used as reinforcing agents in such composites Pendent propargyl groups serve as latent cross-linking agents in new series of polyamide resins.

  14. An electronic aromaticity index for large rings.

    Science.gov (United States)

    Matito, Eduard

    2016-04-28

    We introduce a new electronic aromaticity index, AV1245, consisting of an average of the 4-center multicenter indices (MCI) along the ring that keeps a positional relationship of 1, 2, 4, 5. AV1245 measures the extent of transferability of the delocalized electrons between bonds 1-2 and 4-5, which is expected to be large in conjugated circuits and, therefore, in aromatic molecules. A new algorithm for the calculation of MCI for large rings is also introduced and used to produce the data for the calibration of the new aromaticity index. AV1245 does not rely on reference values, does not suffer from large numerical precision errors, and it does not present any limitation on the nature of atoms, the molecular geometry or the level of calculation. It is a size-extensive measure with low computational cost that grows linearly with the number of ring members. Therefore, it is especially suitable to study the aromaticity of large molecular rings such as those occurring in belt-shaped Möbius structures or porphyrins. The analysis of AV1245 in free-base and bis-metalated Pd [32]octaphyrins(1,0,1,0,1,0,1,0) completes this study. PMID:26878146

  15. Fused aromatic thienopyrazines: structure, properties and function

    KAUST Repository

    Mondal, Rajib

    2010-01-01

    Recent development of a fused aromatic thieno[3.4-b]pyrazine system and their application in optoelectronic devices are reviewed. Introduction of a fused aromatic unit followed by side chain engineering, dramatically enhanced the charge carrier mobility in thin film transistor devices and mobilities up to 0.2 cm2/Vs were achieved. The optoelectronic properties of these fused aromatic thienopyrazine polymers (Eg = 1.3 to 1.6 eV, HOMO = -4.9 to -5.2 V) were tuned by introduction of various fused aromatic rings within thienopyrazine. By balancing the fundamental properties of these polymers, both high charge carrier mobilities and moderate PCEs in solar cells were achieved. Further, effects of copolymerizing units are discussed. Low band gap semiconducting polymer (Eg ∼ 1 eV) with high field effect mobility (0.044 cm2/Vs) was obtained using cyclopentadithiophene as copolymerizing unit. Finally, a molecular design approach to enhance the absorption coefficients is discussed, which resulted in improved power conversion efficiency in bulk heterojunction solar cells. © 2010 The Royal Society of Chemistry.

  16. Silicone elastomers with aromatic voltage stabilizers

    DEFF Research Database (Denmark)

    A Razak, Aliff Hisyam; Skov, Anne Ladegaard

    enhanced electrical breakdown strength due to delocalized pi-electrons of aromatic rings attached to the silicone backbone. The dielectric relative permittivity of PDMS-PPMS copolymers remained between 2 to3 with low conductivity and low dielectric loss as well as high storage moduli with low viscousloss...

  17. Dihydrodiol dehydrogenase and polycyclic aromatic hydrocarbon metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Smithgall, T.E.

    1986-01-01

    Carcinogenic activation of polycyclic aromatic hydrocarbons by microsomal monoxygenases proceeds through trans-dihydrodiol metabolites to diol-epoxide ultimate carcinogens. This thesis directly investigated the role of dihydrodiol dehydrogenase, a cytosolic NAD(P)-linked oxidoreductase, in the detoxification of polycyclic aromatic trans-dihydrodiols. A wide variety of non-K-region trans-dihydrodiols were synthesized and shown to be substrates for the homogeneous rat liver dehydrogenase, including several potent proximate carcinogens derived from 7,12-dimethylbenz(a)anthracene, 5-methylchrysene, and benzo(a)pyrene. Since microsomal activation of polycyclic aromatic hydrocarbons is highly stereospecific, the stereochemical course of enzymatic trans-dihydrodiol oxidation was monitored using circular dichroism spectropolarimetry. The major product formed from the dehydrogenase-catalyzed oxidation of the trans-1,2-dihydrodiol of naphthalene was characterized using UV, IR, NMR, and mass spectroscopy, and appears to be 4-hydroxy-1,2-naphthoquinone. Mass spectral analysis suggests that an analogous hydroxylated o-quinone is formed as the major product of benzo(a)pyrene-7,8-dihydrodiol oxidation. Enzymatic oxidation of trans-dihydrodiols was shown to be potently inhibited by all of the major classes of the nonsteroidal antiinflammatory drugs. Enhancement of trans-dihydrodiol proximate carcinogen oxidation may protect against possible adverse effects of the aspirin-like drugs, and help maintain the balance between activation and detoxification of polycyclic aromatic hydrocarbons.

  18. Design of feedback control systems for unstable plants with saturating actuators

    Science.gov (United States)

    Kapasouris, Petros; Athans, Michael; Stein, Gunter

    1988-01-01

    A new control design methodology is introduced for multi-input/multi-output systems with unstable open loop plants and saturating actuators. A control system is designed using well known linear control theory techniques and then a reference prefilter is introduced so that when the references are sufficiently small, the control system operates linearly as designated. For signals large enough to cause saturations, the control law is modified in such a way to ensure stability and to preserve, to the extent possible, the behavior of the linear control design. Key benefits of this methodology are: the modified feedback system never produces saturating control signals, integrators and/or slow dynamics in the compensator never windup, the directionaL properties of the controls are maintained, and the closed loop system has certain guaranteed stability properties. The advantages of the new design methodology are illustrated in the simulation of an approximation of the AFTI-16 (Advanced Fighter Technology Integration) aircraft multivariable longitudinal dynamics.

  19. Saturation dynamics and working limits of saturated absorption cavity ringdown spectroscopy.

    Science.gov (United States)

    Sadiek, Ibrahim; Friedrichs, Gernot

    2016-08-17

    Cavity ringdown spectroscopy (CRDS) in the linear absorption regime is a well-established method for sensitive trace gas detection, but only a few studies have addressed quantitative measurements in the presence of a saturated sample. In fact, saturation is usually avoided in order to escape from the required complex modeling of the saturation process that depends on the characteristics of the absorbing species, its interaction with the surrounding gas as well as on the temporal and spectral characteristics of the cavity excitation. Conversely, the novel saturated-absorption cavity ringdown spectroscopy approach (SCAR/Sat-CRDS) takes advantage of sample saturation in order to allow one to extract both the gas absorption and the empty cavity loss rates from a single ringdown event. Using a new continuous-wave infrared CRD spectrometer equipped with a tunable narrow-bandwidth high-power OPO laser system and a 18 bit digitizer, the transient dynamics of absorption saturation and the working limits of the Sat-CRDS approach in terms of its ability to extract reliable trace gas concentrations have been experimentally studied in this work. Using a strong methane transition as a test case, the excitation power P0 and saturation power PS have been systematically varied to explore a wide range of saturation regimes. At pressures 5 μbar γc, a pronounced coupling between the two parameters has been observed. Finally, a standard error analysis was performed revealing that the Sat-CRDS approach holds its advantages over conventional CRDS implementations in particular when the attainable ultimate detection sensitivity is limited by uncertainties in the empty cavity ringdown constant. PMID:27488884

  20. Space Charge Saturated Sheath Regime and Electron Temperature Saturation in Hall Thrusters

    Energy Technology Data Exchange (ETDEWEB)

    Y. Raitses; D. Staack; A. Smirnov; N.J. Fisch

    2005-03-16

    Secondary electron emission in Hall thrusters is predicted to lead to space charge saturated wall sheaths resulting in enhanced power losses in the thruster channel. Analysis of experimentally obtained electron-wall collision frequency suggests that the electron temperature saturation, which occurs at high discharge voltages, appears to be caused by a decrease of the Joule heating rather than by the enhancement of the electron energy loss at the walls due to a strong secondary electron emission.

  1. Aromatic oligoamides with a rare ortho-connectivity

    DEFF Research Database (Denmark)

    Hjelmgaard, T.; Nielsen, John

    2013-01-01

    Even though aromatic oligoamides composed of aromatic amino acids in a "one-way sequence" attract ever increasing research interest, backbones connected through ortho-linked aromatics remain rare. Herein, we present the first synthesis and study of N-alkylated ortho-aminomethyl- benzamides termed...

  2. 40 CFR 721.5762 - Aromatic aldehyde phenolic resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic aldehyde phenolic resin... Specific Chemical Substances § 721.5762 Aromatic aldehyde phenolic resin (generic). (a) Chemical substance... aromatic aldehyde phenolic resin (PMN P-01-573) is subject to reporting under this section for...

  3. 40 CFR 721.2673 - Aromatic epoxide resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic epoxide resin (generic). 721... Substances § 721.2673 Aromatic epoxide resin (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aromatic epoxide resin (PMN...

  4. Attitude control with active actuator saturation prevention

    Science.gov (United States)

    Forbes, James Richard

    2015-02-01

    Spacecraft attitude control in the presence of actuator saturation is considered. The attitude controller developed has two components: a proportional component and an angular velocity component. The proportional control has a special form that depends on the attitude parameterization. The angular velocity control is realized by a strictly positive real system with its own input nonlinearity. The strictly positive real system can filter noise in the angular velocity measurement. With this control architecture the torques applied to the body are guaranteed to be below a predetermined value, thus preventing saturation of the actuators. The closed-loop equilibrium point corresponding to the desired attitude is shown to be asymptotically stable. Additionally, the control law does not require specific knowledge of the body's inertia properties, and is therefore robust to such modelling errors.

  5. The Danish tax on saturated fat

    DEFF Research Database (Denmark)

    Jensen, Jørgen Dejgård; Smed, Sinne

    2013-01-01

    Denmark introduced a new tax on saturated fat in food products with effect from October 2011. The objective of this paper is to make an effect assessment of this tax for some of the product categories most significantly affected by the new tax, namely fats such as butter, butter-blends, margarine...... and oils. This assessment is done by conducting an econometric analysis on weekly food purchase data from a large household panel dataset (GfK Consumer Tracking Scandinavia), spanning the period from January 2008 until July 2012.The econometric analysis suggest that the introduction of the tax on...... saturated fat in food products has had some effects on the market for the considered products, in that the level of consumption of fats dropped by 10 – 20%. Furthermore, the analysis points at shifts in demand from high-price supermarkets towards low-price discount stores – at least for some types of oils...

  6. Scaling of saturation amplitudes in baroclinic instability

    International Nuclear Information System (INIS)

    By using finite-amplitude conservation laws for pseudomomentum and pseudoenergy, rigorous upper bounds have been derived on the saturation amplitudes in baroclinic instability for layered and continuously-stratified quasi-geostrophic models. Bounds have been obtained for both the eddy energy and the eddy potential enstrophy. The bounds apply to conservative (inviscid, unforced) flow, as well as to forced-dissipative flow when the dissipation is proportional to the potential vorticity. This approach provides an efficient way of extracting an analytical estimate of the dynamical scalings of the saturation amplitudes in terms of crucial non-dimensional parameters. A possible use is in constructing eddy parameterization schemes for zonally-averaged climate models. The scaling dependences are summarized, and compared with those derived from weakly-nonlinear theory and from baroclinic-adjustment estimates

  7. Wave propagation in thermoelastic saturated porous medium

    Indian Academy of Sciences (India)

    M D Sharma

    2008-12-01

    Biot ’s theory for wave propagation in saturated porous solid is modified to study the propagation of thermoelastic waves in poroelastic medium. Propagation of plane harmonic waves is considered in isotropic poroelastic medium. Relations are derived among the wave-induced temperature in the medium and the displacements of fluid and solid particles. Christoffel equations obtained are modified with the thermal as well as thermoelastic coupling parameters. These equations explain the existence and propagation of four waves in the medium. Three of the waves are attenuating longitudinal waves and one is a non-attenuating transverse wave. Thermal properties of the medium have no effect on the transverse wave. The velocities and attenuation of the longitudinal waves are computed for a numerical model of liquid-saturated sandstone. Their variations with thermal as well as poroelastic parameters are exhibited through numerical examples.

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

    OpenAIRE

    SipilÀ, Timo

    2009-01-01

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

  9. The coordination chemistry of saturated molecules

    OpenAIRE

    Bercaw, John E.; Labinger, Jay A.

    2007-01-01

    Our understanding of bonding in transition metal complexes, as well as our ability to use that understanding in the synthesis and application of new species, has evolved over the last 100 years; and in some sense this special feature on the coordination chemistry of saturated molecules may be considered to represent its culmination. The nature of complexes between transition metal ions and neutral molecules such as ammonia was first correctly described by Werner around the beginning of the 20...

  10. Saturation and Critical Phenomena in DIS

    OpenAIRE

    Jenkovszky, L. L.; Troshin, S. M.; Tyurin, N. E.

    2009-01-01

    It is argued that the expected turn-down in $x- Q^2$ of the cross sections (structure functions $F_2(x,Q^2)$), assumed to result from the saturation of parton densities in the nucleon, is related to a phase transition from the (almost) ideal partonic gas, obeying Bjorken scaling, to a partonic "liquid". This can be quantified in the framework of statistical models, percolation and other approaches to collective phenomena of the strongly interacting matter. Similarities and differences between...

  11. Flux saturation length of sediment transport

    OpenAIRE

    Pähtz, T.; Kok, JF; Parteli, EJR; Herrmann, HJ

    2013-01-01

    Sediment transport along the surface drives geophysical phenomena as diverse as wind erosion and dune formation. The main length-scale controlling the dynamics of sediment erosion and deposition is the saturation length $L_\\mathrm{s}$, which characterizes the flux response to a change in transport conditions. Here we derive, for the first time, an expression predicting $L_\\mathrm{s}$ as a function of the average sediment velocity under different physical environments. Our expression accounts ...

  12. 2D Saturable Absorbers for Fibre Lasers

    Directory of Open Access Journals (Sweden)

    Robert I. Woodward

    2015-11-01

    Full Text Available Two-dimensional (2D nanomaterials are an emergent and promising platform for future photonic and optoelectronic applications. Here, we review recent progress demonstrating the application of 2D nanomaterials as versatile, wideband saturable absorbers for Q-switching and mode-locking fibre lasers. We focus specifically on the family of few-layer transition metal dichalcogenides, including MoS2, MoSe2 and WS2.

  13. Optimal oxygen saturation in premature infants

    OpenAIRE

    Meayoung Chang

    2011-01-01

    There is a delicate balance between too little and too much supplemental oxygen exposure in premature infants. Since underuse and overuse of supplemental oxygen can harm premature infants, oxygen saturation levels must be monitored and kept at less than 95% to prevent reactive oxygen species-related diseases, such as retinopathy of prematurity and bronchopulmonary dysplasia. At the same time, desaturation below 80 to 85% must be avoided to prevent adverse consequences, such as cerebra...

  14. Complex steel saturation with niobium and vanadium

    International Nuclear Information System (INIS)

    Studies on determining possibility of niobium and vanadium alloying with carbides were conducted. Possibility of simultaneous saturation of carbon steels with niobium and vanadium was established. Diffusion layers coated on surfaces of 45, U8A and U10A steels under different conditions. It is shown that increase of coating density by means of alloying favours the increase of its corrosion resistance in water and aqueous solutions of salt and soda 2 times, wear resistance -1.6-5 times

  15. Optimal oxygen saturation in premature infants

    Directory of Open Access Journals (Sweden)

    Meayoung Chang

    2011-09-01

    Full Text Available There is a delicate balance between too little and too much supplemental oxygen exposure in premature infants. Since underuse and overuse of supplemental oxygen can harm premature infants, oxygen saturation levels must be monitored and kept at less than 95% to prevent reactive oxygen species-related diseases, such as retinopathy of prematurity and bronchopulmonary dysplasia. At the same time, desaturation below 80 to 85% must be avoided to prevent adverse consequences, such as cerebral palsy. It is still unclear what range of oxygen saturation is appropriate for premature infants; however, until the results of further studies are available, a reasonable target for pulse oxygen saturation (SpO2 is 90 to 93% with an intermittent review of the correlation between SpO2 and the partial pressure of arterial oxygen tension (PaO2. Because optimal oxygenation depends on individuals at the bedside making ongoing adjustments, each unit must define an optimal target range and set alarm limits according to their own equipment or conditions. All staff must be aware of these values and adjust the concentration of supplemental oxygen frequently.

  16. Modeling of synchronous machines with magnetic saturation

    Energy Technology Data Exchange (ETDEWEB)

    Rehaoulia, H. [Universite de Tunis-Ecole Superieure des Sciences et Techniques de Tunis (Unite de Recherche CSSS), 5 Avenue Taha Hussein Tunis 10008 (Tunisia); Henao, H.; Capolino, G.A. [Universite de Picardie Jules Vernes-Centre de Robotique, d' Electrotechnique et d' Automatique (UPRES-EA3299), 33 Rue Saint Leu, 80039 Amiens Cedex 1 (France)

    2007-04-15

    This paper deals with a method to derive multiple models of saturated round rotor synchronous machines, based on different selections of state-space variables. By considering the machine currents and fluxes as space vectors, possible d-q models are discussed and adequately numbered. As a result several novel models are found and presented. It is shown that the total number of d-q models for a synchronous machine, with basic dampers, is 64 and therefore much higher than known. Found models are classified into three families: current, flux and mixed models. These latter, the mixed ones, constitute the major part (52) and hence offer a large choice. Regarding magnetic saturation, the paper also presents a method to account for whatever the choice of state-space variables. The approach consists of just elaborating the saturation model with winding currents as main variables and deriving all the other models from it, by ordinary mathematical manipulations. The paper emphasizes the ability of the proposed approach to develop any existing model without exception. An application to prove the validity of the method and the equivalence between all developed models is reported. (author)

  17. Synthesis and stereochemical investigation of potential saturated heterocyclic drugs Pt. 1

    International Nuclear Information System (INIS)

    Studies of partially and fully saturated heterocyclic compounds with condensed skeleton containing two heteroatoms are presented. The synthesis, stereochemical and conformation analyses aimed at the synthesis of potential drugs. Dihydro- and tetrahydro-1,3-oxazines were prepared from alicyclic 1,3-amino-alcohols by ring closure with aldehydes or imide esters. 1,3-oxazine-4-one derivatives were prepared by reacting alicyclic cis- and trans-2-hydroxy-1-carboxamides with aliphatic or aromatic aldehides. The conformations of the compounds prepared were determined by means of NMR spectroscopy. The main results of the determination of the steric structure of some representatives of the above described families of compounds by means of X-ray diffraction analysis are also presented. (author)

  18. Aromatic Structure in Simulates Titan Aerosol

    Science.gov (United States)

    Trainer, Melissa G.; Loeffler, M. J.; Anderson, C. M.; Hudson, R. L.; Samuelson, R. E.; Moore, M. A.

    2011-01-01

    Observations of Titan by the Cassini Composite Infrared Spectrometer (CIRS) between 560 and 20 per centimeter (approximately 18 to 500 micrometers) have been used to infer the vertical variations of Titan's ice abundances, as well as those of the aerosol from the surface to an altitude of 300 km [1]. The aerosol has a broad emission feature centered approximately at 140 per centimeter (71 micrometers). As seen in Figure 1, this feature cannot be reproduced using currently available optical constants from laboratory-generated Titan aerosol analogs [2]. The far-IR is uniquely qualified for investigating low-energy vibrational motions within the lattice structures of COITIDlex aerosol. The feature observed by CIRS is broad, and does not likely arise from individual molecules, but rather is representative of the skeletal movements of macromolecules. Since Cassini's arrival at Titan, benzene (C6H6) has been detected in the atmosphere at ppm levels as well as ions that may be polycyclic aromatic hydrocarbons (PAHs) [3]. We speculate that the feature may be a blended composite that can be identified with low-energy vibrations of two-dimensional lattice structures of large molecules, such as PAHs or nitrogenated aromatics. Such structures do not dominate the composition of analog materials generated from CH4 and N2 irradiation. We are performing studies forming aerosol analog via UV irradiation of aromatic precursors - specifically C6H6 - to understand how the unique chemical architecture of the products will influence the observable aerosol characteristics. The optical and chemical properties of the aromatic analog will be compared to those formed from CH4/N2 mixtures, with a focus on the as-yet unidentified far-IR absorbance feature. Preliminary results indicate that the photochemically-formed aromatic aerosol has distinct chemical composition, and may incorporate nitrogen either into the ring structure or adjoined chemical groups. These compositional differences are

  19. Structural description of aromatic core in residue fractions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.C.; Sun, W.F.; Fang, X.C.; Guan, M.H. [Fushun Research Inst. of Petroleum and Petrochemicals, Fushun, Liaoning (China)

    2008-07-01

    The chemical structures of a polycyclic aromatic core in Oman residue fractions was examined using proton nuclear magnetic resonance spectroscopy (1H-NMR), synchronous fluorescence spectrometry (SFS) and ruthenium ions catalyzed oxidation (RICO). It was important to understand the aromatic core structure in heavy oil fractions, including aromatic rings system size and condensed type. The types and content of benzenepolycarboxylic acids disclosed the condensed types of aromatic rings in core. Biphenyl fraction (BIPH), cata-condensed fraction (CATA), peri-condensed fraction (PERI) and condensed index (BCI) were calculated by benzenepolycarboxylic acids. The results from 1H-NMR showed that about 3.2 aromatic rings were in the aromatics core, 5.6 rings were in the resins unit, and 8.2 rings were in the asphaltenes unit. This paper also described the aromatic rings distribution of residue fractions as determined by SFS. The type and content of benzenepolycarboxylic acids from RICO of residue fractions suggested the condensed mode of rings in the aromatic core. The most cata-condensed type aromatic structures were in aromatics, the whole peri-condensed type were in asphaltenes, while the dominant peri-condensed type, as well as some quantity of cata-condensed type structures existed together in resins. Aromatics, resins and asphaltenes were given likely structural models based on results from this study. 8 refs., 3 tabs., 7 figs.

  20. Open Babel: An open chemical toolbox

    Directory of Open Access Journals (Sweden)

    O'Boyle Noel M

    2011-10-01

    Full Text Available Abstract Background A frequent problem in computational modeling is the interconversion of chemical structures between different formats. While standard interchange formats exist (for example, Chemical Markup Language and de facto standards have arisen (for example, SMILES format, the need to interconvert formats is a continuing problem due to the multitude of different application areas for chemistry data, differences in the data stored by different formats (0D versus 3D, for example, and competition between software along with a lack of vendor-neutral formats. Results We discuss, for the first time, Open Babel, an open-source chemical toolbox that speaks the many languages of chemical data. Open Babel version 2.3 interconverts over 110 formats. The need to represent such a wide variety of chemical and molecular data requires a library that implements a wide range of cheminformatics algorithms, from partial charge assignment and aromaticity detection, to bond order perception and canonicalization. We detail the implementation of Open Babel, describe key advances in the 2.3 release, and outline a variety of uses both in terms of software products and scientific research, including applications far beyond simple format interconversion. Conclusions Open Babel presents a solution to the proliferation of multiple chemical file formats. In addition, it provides a variety of useful utilities from conformer searching and 2D depiction, to filtering, batch conversion, and substructure and similarity searching. For developers, it can be used as a programming library to handle chemical data in areas such as organic chemistry, drug design, materials science, and computational chemistry. It is freely available under an open-source license from http://openbabel.org.

  1. Porosity determination of self-compacting concretes using combined forced saturation

    OpenAIRE

    Desmet, Bram; Serrano, Hernandez; Vantomme, John; Feys, Dimitri; De Schutter, Geert; Elsen, Jan; Cizer, Özlem; Heirman, Gert; Vandewalle, Lucie; Gemert, Dionys van

    2011-01-01

    The superplasticizers (SP) and high mineral addition contents used in self-compacting concrete (SCC) can have an important effect on the porosity of the hardened mixtures, influencing their durability and strength. In this paper, a combination of forced vacuum and boiling saturation techniques is used to determine the influence of the composition of seven SCC concretes on the open porosity. The mixtures differ by the type of addition (quartzite, fly ash and two types of limestone addition), t...

  2. PLD-grown thin film saturable absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Tellkamp, Friedjof

    2012-11-01

    The subject of this thesis is the preparation and characterization of thin films made of oxidic dielectrics which may find their application as saturable absorber in passively Q-switched lasers. The solely process applied for fabrication of the thin films was the pulsed laser deposition (PLD) which stands out against other processes by its flexibility considering the composition of the systems to be investigated. Within the scope of this thesis the applied saturable absorbers can be divided into two fundamentally different kinds of functional principles: On the one hand, saturable absorption can be achieved by ions embedded in a host medium. Most commonly applied bulk crystals are certain garnets like YAG (Y{sub 3}Al{sub 5}O{sub 12}) or the spinel forsterite (Mg{sub 2}SiO{sub 4}), in each case with chromium as dopant. Either of these media was investigated in terms of their behavior as PLD-grown saturable absorber. Moreover, experiments with Mg{sub 2}GeO{sub 4}, Ca{sub 2}GeO{sub 4}, Sc{sub 2}O{sub 3}, and further garnets like YSAG or GSGG took place. The absorption coefficients of the grown films of Cr{sup 4+}:YAG were determined by spectroscopic investigations to be one to two orders of magnitude higher compared to commercially available saturable absorbers. For the first time, passive Q-switching of a Nd:YAG laser at 1064 nm with Cr{sup 4+}:YAG thin films could be realized as well as with Cr:Sc{sub 2}O{sub 3} thin films. On the other hand, the desirable effect of saturable absorption can also be generated by quantum well structures. For this purpose, several layer system like YAG/LuAG, Cu{sub 2}O/MgO, and ZnO/corumdum were investigated. It turned out that layer systems with indium oxide (In{sub 2}O{sub 3}) did not only grew in an excellent way but also showed up a behavior regarding their photo luminescence which cannot be explained by classical considerations. The observed luminescence at roughly 3 eV (410 nm) was assumed to be of excitonic nature and its

  3. Radiation chemistry of aromatic dimer radical cations

    International Nuclear Information System (INIS)

    π-π Interactions of aromatic molecules are paid attention much in many fields, especially biology, chemistry, and applied physics, represented as protein, DNA, electron donor-accepter complexes, charge transfers, and self assembly molecules. Aromatic molecules including benzene rings are the simplest case to study the π-π interactions. To interpret the charge resonance (CR) structure in the dimer radical cations, spectroscopic and ESR methods have been carried out. The spectroscopic study on the dimer radical ion of molecules with two chromophores would be profitable to identify the electronic and configurational properties. In this article, dynamics of the dimer radical cation of benzenes, polystyrenes, and resist polymers is described on the basis of direct observation of CR band by the nanosecond pulse radiolysis and low temperature γ-radiolysis methods. (author)

  4. Starlike aluminum-carbon aromatic species.

    Science.gov (United States)

    Wu, Yan-Bo; Jiang, Jin-Liang; Lu, Hai-Gang; Wang, Zhi-Xiang; Perez-Peralta, Nancy; Islas, Rafael; Contreras, Maryel; Merino, Gabriel; Wu, Judy I-Chia; Schleyer, Paul von Ragué

    2011-01-10

    Is it possible to achieve molecules with starlike structures by replacing the H atoms in (CH)(n)(q) aromatic hydrocarbons with aluminum atoms in bridging positions? Although D(4h) C(4)Al(4)(2-) and D(2) C(6)Al(6) are not good prospects for experimental realization, a very extensive computational survey of fifty C(5)Al(5)(-) isomers identified the starlike D(5h) global minimum with five planar tetracoordinate carbon atoms to be a promising candidate for detection by photoelectron detachment spectroscopy. BOMD (Born-Oppenheimer molecular dynamics) simulations and high-level theoretical computations verified this conclusion. The combination of favorable electronic and geometric structural features (including aromaticity and optimum C-Al-C bridge bonding) stabilizes the C(5)Al(5)(-) star preferentially. PMID:21207593

  5. Synthesis of aromatic cytokinins for plant biotechnology.

    Science.gov (United States)

    Plíhalová, Lucie; Vylíčilová, Hana; Doležal, Karel; Zahajská, Lenka; Zatloukal, Marek; Strnad, Miroslav

    2016-09-25

    Cytokinins represent an important group of plant growth regulators that can modulate several biotechnological processes owing to their ability to influence almost all stages of plant development and growth. In addition, the use of purine based cytokinins with aromatic substituent in C6 position of the purine moiety in tissue culture techniques is currently experiencing a surge in interest, made possible by the ongoing systematic synthesis and study of these compounds. This review article outlines progress in the synthesis of aromatic cytokinins, the in vitro and in vivo effects of these substances and insights gleaned from their synthesis. As the purine moiety in these compounds can be substituted at several positions, we examine each of the substitution possibilities in relation to the derivatives prepared so far. The discussion highlights the gradual simplification of their preparation in relation to their application in practice and summarizes the relevant organic chemistry literature and published patents. PMID:26703810

  6. Trans Fat Now Listed With Saturated Fat and Cholesterol

    Science.gov (United States)

    ... Trans Fat Now Listed With Saturated Fat and Cholesterol Share Tweet Linkedin Pin it More sharing options ... I Do About Saturated Fat, Trans Fat, and Cholesterol? When comparing foods, look at the Nutrition Facts ...

  7. Hole-hole propagation and saturation

    International Nuclear Information System (INIS)

    Ladder contributions to the effective interaction are calculated with inclusion of hole-hole (hh) propagation to all orders. For a correct calculation of the self-energy resulting from the ladder-summed effective interaction, ΓL, dispersion relations are used numerically. The single-particle (sp) energy is calculated self-consistently from the real on-shell self-energy. The contribution of the hh terms leads to a repulsive contribution to the energy per particle which increases with density. This saturation mechanism has not been identified previously and results are presented for the ν2 homework potential. (orig.)

  8. The Danish tax on saturated fat

    DEFF Research Database (Denmark)

    Vallgårda, Signild; Holm, Lotte; Jensen, Jørgen Dejgård

    2015-01-01

    arguments and themes involved in the debates surrounding the introduction and the repeal. SUBJECTS/METHODS: An analysis of parliamentary debates, expert reports and media coverage; key informant interviews; and a review of studies about the effects of the tax on consumer behaviour. RESULTS: A tax on......BACKGROUND/OBJECTIVES: Health promoters have repeatedly proposed using economic policy tools, taxes and subsidies, as a means of changing consumer behaviour. As the first country in the world, Denmark introduced a tax on saturated fat in 2011. It was repealed in 2012. In this paper, we present...... research indicates that the tax was effective in changing consumer behaviour....

  9. The danish tax on saturated fat

    DEFF Research Database (Denmark)

    Jensen, Jørgen Dejgård; Smed, Sinne

    and oils. This assessment was done by conducting an econometric analysis on weekly food purchase data from a large household panel dataset (GfK ConsumerTracking Scandinavia), spanning the period from January 2009 until December 2011.The econometric analysis suggest that the introduction of the tax on...... saturated fat in food products has had some effects on the market for the considered products, in that the level of consumption of fats dropped by 10 – 20%. Furthermore, the analysis points at shifts in demand from high-price supermarkets towards low-price discount stores – a shift that seems to have been...

  10. Saturation point structure of marine stratocumulus clouds

    Science.gov (United States)

    Boers, Reinout; Betts, Alan K.

    1988-01-01

    An investigation of the microstructure of a Pacific stratocumulus capped boundary layer is presented. A complex structure of three branches, identified using conserved variable diagrams, is found to correspond well to a conceptual model for the unstable, radiatively cooled cloud topped boundary layer. A simple conditional sampling method was used to identify saturation point pairs for ascending and descending branches of the internal boundary layer circulation. Results indicate a primary circulation scale of 5 km and provide a reasonable cloud top entrainment rate of 1 cm/s.

  11. LABORATORY STUDY ON CRACKS IN SATURATED SANDS

    Institute of Scientific and Technical Information of China (English)

    Peng Fujiao; Tan Qingming; Che-Min Cheng

    2000-01-01

    It has been reported[1]that when a loosely packed column of saturated sand in a vertical cylindrical container is shock loaded axially by dropping to the floor,large horizontal cracks initiate,grow and eventually fade away in the sand as it settles under gravity.This paper shows that a similar phenomenon can also be observed when shock loading is replaced by forcing water to percolate upward through the sand column.It is believed that our result sheds further light on the physics of formation of these cracks.

  12. Elevated transferrin saturation and risk of diabetes

    DEFF Research Database (Denmark)

    Ellervik, Christina; Mandrup-Poulsen, Thomas; Andersen, Henrik Ullits;

    2011-01-01

    OBJECTIVE We tested the hypothesis that elevated transferrin saturation is associated with an increased risk of any form of diabetes, as well as type 1 or type 2 diabetes separately. RESEARCH DESIGN AND METHODS We used two general population studies, The Copenhagen City Heart Study (CCHS, N = 9......,121) and The Copenhagen General Population Study (CGPS, N = 24,195), as well as a 1:1 age- and sex-matched population-based case-control study with 6,129 patients with diabetes from the Steno Diabetes Centre and 6,129 control subjects, totaling 8,535 patients with diabetes and 37,039 control subjects...

  13. Saturation Effects in Hadronic Cross Sections

    OpenAIRE

    Shoshi, Arif I.; Steffen, Frank D.

    2002-01-01

    We compute total and differential elastic cross sections of high-energy hadronic collisions in the loop-loop correlation model that provides a unified description of hadron-hadron, photon-hadron, and photon-photon reactions. The impact parameter profiles of pp and gamma*p collisions are calculated. For ultra-high energies the hadron opacity saturates at the black disc limit which tames the growth of the hadronic cross sections in agreement with the Froissart bound. We compute the impact param...

  14. Gas transport through saturated bentonite and interfaces

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. The aim of this investigation was the determination of the gas transport properties of saturated compacted bentonite and its interfaces. The bentonite used was the Spanish FEBEX bentonite, which is mainly composed of montmorillonite (more than 90%). For a dry density of 1.6 g/cm3 the saturated permeability of the bentonite is about 5.10-14 m/s, with deionised water used as percolating fluid. The saturated swelling pressure for the same dry density has a value of about 6 MPa. To perform the gas breakthrough tests a series of stainless steel cells were designed and manufactured. The cells consisted of a body, in which the cylindrical sample was inserted, pistons with o-rings at both ends of the samples and threaded caps. The samples, of 3.8 and 5.0 cm in diameter and 2.5 or 5.0 in height, were obtained by uniaxial compaction of the bentonite with its hygroscopic water content directly inside the cell body. Saturation with deionised water was accomplished by applying injection pressures of between 2 and 10 bar. The water content of the bentonite after saturation was higher than 27% for all the dry densities. Once the samples saturated, the filters on top and bottom of the samples were replaced by dry ones, the cells were again closed, and they were connected to a setup specially designed to measure breakthrough pressure. It consisted of two stainless steel deposits connected to the ends of the cell. One of the deposits was pressurised with nitrogen at 2 bar, whereas vacuum was applied to the other one. The pressures were measured by means of pressure transmitters. If no changes in pressure were recorded during 24 h, the injection pressure in the upstream deposit was increased by 2 bar and kept constant for 24 h. The process was repeated until gas started to flow through the sample. The time required for the completion of a particular experiment was determined by the conditions of the sample being studied. Although

  15. Dispersants as Used in Response to the MC252-Spill Lead to Higher Mobility of Polycyclic Aromatic Hydrocarbons in Oil-Contaminated Gulf of Mexico Sand

    OpenAIRE

    Zuijdgeest, A.; M. Huettel

    2012-01-01

    After the explosion of the Deepwater Horizon oil rig, large volumes of crude oil were washed onto and embedded in the sandy beaches and sublittoral sands of the Northern Gulf of Mexico. Some of this oil was mechanically or chemically dispersed before reaching the shore. With a set of laboratory-column experiments we show that the addition of chemical dispersants (Corexit 9500A) increases the mobility of polycyclic aromatic hydrocarbons (PAHs) in saturated permeable sediments by up to two orde...

  16. Carcinogenic potential of hydrotreated petroleum aromatic extracts.

    OpenAIRE

    Doak, S. M.; Hend, R W; van der Wiel, A; Hunt, P F

    1985-01-01

    Five experimental petroleum extracts were produced from luboil distillates derived from Middle East paraffinic crude by solvent extraction and severe hydrotreatment. The polycyclic aromatic content (PCA) of the extracts was determined by dimethyl sulphoxide extraction and ranged from 3.7-9.2% w/w. The five extracts were evaluated for their potential to induce cutaneous and systemic neoplasia in female mice derived from Carworth Farm No 1 strain (CF1). The test substances were applied undilute...

  17. Aromatic compounds from three Brazilian Lauraceae species

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Andrea Nastri de Luca; Batista Junior, Joao Marcos; Lopez, Silvia Noeli; Furlan, Maysa; Cavalheiro, Alberto Jose; Silva, Dulce Helena Siqueira; Bolzani, Vanderlan da Silva [UNESP, Araraquara, SP (Brazil). Inst. de Quimica. Dept. de Quimica Organica; Nunomura, Sergio Massayoshi [Instituto Nacional de Pesquisa da Amazonia (INPA), Manaus, AM (Brazil). Dept. de Produtos Naturais; Yoshida, Massayoshi [Centro de Biotecnologia da Amazonia, Manaus, AM (Brazil)

    2010-07-01

    Phytochemical investigations on three Brazilian Lauraceae species from the Cerrado region of Sao Paulo State, Ocotea corymbosa (Meins) Mez., O. elegans Mez. and Persea pyrifolia Nees and Mart. ex Nees resulted in the isolation of flavonoids, an ester of the 4-O-E-caffeoylquinic acid, an aromatic sesquiterpene besides furofuran lignans. This is the first chemical study on the leaves of Ocotea elegans and O. corymbosa as well as the first report of non-volatile compounds from Persea pyrifolia. (author)

  18. Aromatic compounds from three Brazilian Lauraceae species

    International Nuclear Information System (INIS)

    Phytochemical investigations on three Brazilian Lauraceae species from the Cerrado region of Sao Paulo State, Ocotea corymbosa (Meins) Mez., O. elegans Mez. and Persea pyrifolia Nees and Mart. ex Nees resulted in the isolation of flavonoids, an ester of the 4-O-E-caffeoylquinic acid, an aromatic sesquiterpene besides furofuran lignans. This is the first chemical study on the leaves of Ocotea elegans and O. corymbosa as well as the first report of non-volatile compounds from Persea pyrifolia. (author)

  19. Decarboxylative and direct functionalisations of aromatic compounds

    OpenAIRE

    Seo, Sangwon

    2014-01-01

    Aromatic rings are privileged structures found in a diverse range of natural and synthetic compounds, thus synthetic methods for their functionalisations are important in organic synthesis. Despite significant advancements made, especially in the field of transition metal catalysis, work still continues for the development of milder, more efficient, and more atom economical reactions. We describe here our efforts towards the development of decarboxylative/direct C(aryl)–N and C(aryl)–C bond f...

  20. AN AROMATIC COMPOUND from CENTAUREA PTOSIMOPAPPOIDES

    OpenAIRE

    A. ULUBELEN, S. ÖKSÜZ

    2015-01-01

    Centaurea ptosimopappoides was previously investigated by our groupand the presence of two new triterpenes were reported. The rare occurrence ofthis type compounds in the plants prompted us to further investigation of Centaureaptosimopappoides. In this work we report the isolation and structure determinationof an aromatic glycoside which was found in the genus Centaureafor the first time. The structure of the compound was determined by spectralmethods.Key words: Centaurea ptosimopappoides; Co...

  1. Synthetic fuel aromaticity and staged combustion

    Energy Technology Data Exchange (ETDEWEB)

    Longanbach, J. R.; Chan, L. K.; Levy, A.

    1982-11-15

    Samples of middle and heavy SRC-II distillates were distilled into 50 C boiling point range fractions. These were characterized by measurements of their molecular weight, elemental analysis and basic nitrogen content and calculation of average molecular structures. The structures typically consisted of 1 to 3 aromatic rings fused to alicyclic rings with short, 1 to 3 carbon aliphatic side chains. The lower boiling fractions contained significant amounts (1 atom/molecule) of oxygen while the heavier fractions contained so few heteroatoms that they were essentially hydrocarbons. Laboratory scale oxidative-pyrolysis experiments were carried out at pyrolysis temperatures of 500 to 1100 C and oxygen concentrations from 0 to 100 percent of stoichiometry. Analysis of liquid products, collected in condensers cooled with liquid nitrogen showed that aromatization is a major reaction in the absence of oxygen. The oxygen-containing materials (phenolics) seem to be more resistant to thermal pyrolysis than unsubstituted aromatics. Nitrogen converts from basic to nonbasic forms at about 500 C. The nonbasic nitrogen is more stable and survives up to 700 C after which it is slowly removed. A recently constructed 50,000 Btu/hr staged combustor was used to study the chemistry of the nitrogen and aromatics. SRC II combustion was studied under fuel-rich, first-stage conditions at air/fuel ratios from 0.6 to 1.0 times stoichiometric. The chemistry of the fuel during combustion calls for further investigation in order to examine the mechanism by which HCN is evolved as a common intermediate for the formation of the nitrogen-containing gaseous combustion products. 25 references, 45 figures, 25 tables.

  2. Transformations of aromatic hydrocarbons over zeolites

    Czech Academy of Sciences Publication Activity Database

    Voláková, Martina; Žilková, Naděžda; Čejka, Jiří

    2008-01-01

    Roč. 34, 5-7 (2008), s. 439-454. ISSN 0922-6168 R&D Projects: GA ČR GA203/05/0197; GA AV ČR 1QS400400560; GA AV ČR KJB4040402 Institutional research plan: CEZ:AV0Z40400503 Keywords : aromatic hydrocarbons * zeolites * alkylation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.514, year: 2008

  3. ANTIEMETIC ACTIVITY OF SOME AROMATIC PLANTS

    OpenAIRE

    Hasan MuhammadMohtasheemul; Ahmed Salman; Ahmed Ziauddin; Azhar Iqbal

    2012-01-01

    Current study was conducted to explore the antiemetic activity of ten aromatic medicinal plants viz., Carissa carandus L. (fruits), Chichorium intybus L (flowers), Cinnamum tamala L (leaves), Curcuma caesia Roxb (rhizomes), Lallemantia royleana Benth (leaves), Matricaria chamomila L (flowers), Piper longum L (fruits), Piper methysticum G. Forst (fruits), Piper nigrum Linn. (fruits) and Syzygium aromaticum (Linn.) Merr. & Perry (flowering buds) was studied using chick emetic model. The ethan...

  4. Spectroscopic Characterisation of Novel Polycyclic Aromatic Polymers

    OpenAIRE

    O'Neill, Luke; Lynch, Patrick; McNamara, Mary; Byrne, Hugh

    2007-01-01

    A series of novel polyphenylenevinylene (PPV) derivative polymers were studied by absorption and photoluminescence spectroscopies. The effect of the sequential introduction of polycyclic aromatic ring substituents into the delocalized backbone was examined with relation to hypsochromatic and bathochromatic shifting. While the replacement of the phenyl units by naphthyl units results in a substantial hypsochromic shift of both the absorption and emission spectra, their subsequent substitution ...

  5. Enhanced phosphorescence emission by incorporating aromatic halides into an entangled coordination framework based on naphthalenediimide.

    Science.gov (United States)

    Martínez-Martínez, Virginia; Sola Llano, Rebeca; Furukawa, Shuhei; Takashima, Yohei; López Arbeloa, Iñigo; Kitagawa, Susumu

    2014-08-25

    Phosphorescence emission at room temperature is turned on in an entangled porous coordination polymer (PCP) with naphthalenediimide (NDI) as chromophore, by incorporating halogenated guests into the pores. The phosphorescent efficiency is drastically increased by the incorporation of aromatic halide guests in comparison with the incorporation of nonaromatic derivatives. Aromatic halide guests trigger a structural transformation, which allows a strong interaction with the NDI ligand in the framework through charge-transfer complexation, and provides an extra population process of the triplet state. The long-lived photoinduced triplet states, with an emission wavelength in the red region of the visible spectrum, demonstrated by this PCP, may open the door for potential uses, for example, as singlet-oxygen generators or for bio-imaging applications. PMID:24953198

  6. Aromatics Oxidation and Soot Formation in Flames

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J. B.; Richter, H.

    2005-03-29

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and the growth process to polycyclic aromatic hydrocarbons (PAH) of increasing size, soot and fullerenes formation in flames. The overall objective of the experimental aromatics oxidation work is to extend the set of available data by measuring concentration profiles for decomposition intermediates such as phenyl, cyclopentadienyl, phenoxy or indenyl radicals which could not be measured with molecular-beam mass spectrometry to permit further refinement and testing of benzene oxidation mechanisms. The focus includes PAH radicals which are thought to play a major role in the soot formation process while their concentrations are in many cases too low to permit measurement with conventional mass spectrometry. The radical species measurements are used in critical testing and improvement of a kinetic model describing benzene oxidation and PAH growth. Thermodynamic property data of selected species are determined computationally, for instance using density functional theory (DFT). Potential energy surfaces are explored in order to identify additional reaction pathways. The ultimate goal is to understand the conversion of high molecular weight compounds to nascent soot particles, to assess the roles of planar and curved PAH and relationships between soot and fullerenes formation. The specific aims are to characterize both the high molecular weight compounds involved in the nucleation of soot particles and the structure of soot including internal nanoscale features indicative of contributions of planar and/or curved PAH to particle inception.

  7. Serum albumin--a non-saturable carrier

    DEFF Research Database (Denmark)

    Brodersen, R; Honoré, B; Larsen, F G

    1984-01-01

    The shape of binding isotherms for sixteen ligands to human serum albumin showed no signs of approaching saturation at high ligand concentrations. It is suggested that ligand binding to serum albumin is essentially different from saturable binding of substrates to enzymes, of oxygen to haemoglobin......, etc. Binding to serum albumin appears to be non-saturable. Udgivelsesdato: 1984-Feb...

  8. Preliminary Saturated-Zone Flow Model

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-06-10

    This milestone consists of an updated fully 3D model of ground-water flow within the saturated zone at Yucca Mountain, Nevada. All electronic files pertaining to this deliverable have been transferred via ftp transmission to Steve Bodnar (M and O) and the technical data base. The model was developed using a flow and transport simulator, FEHMN, developed at Los Alamos National Laboratory, and represents a collaborative effort between staff from the US Geological Survey and Los Alamos National Laboratory. The model contained in this deliverable is minimally calibrated and represents work in progress. The flow model developed for this milestone is designed to feed subsequent transport modeling studies at Los Alamos which also use the FEHMN software. In addition, a general-application parameter estimation routine, PEST, was used in conjunction with FEHMN to reduce the difference between observed and simulated values of hydraulic head through the adjustment of model variables. This deliverable in large part consists of the electronic files for Yucca Mountain Site saturated-zone flow model as it existed as of 6/6/97, including the executable version of FEHMN (accession no. MOL.19970610.0204) used to run the code on a Sun Ultrasparc I workstation. It is expected that users of the contents of this deliverable be knowledgeable about the oration of FEHMN.

  9. Nuclear Magnetic Resonance Measurements of Original Water Saturation and Mobile Water Saturation in Low Permeability Sandstone Gas

    International Nuclear Information System (INIS)

    We use nuclear magnetic resonance (NMR) and centrifugation to measure the original water saturation and mobile water saturation of cores from the Xujiahe low permeability sandstone gas reservoir, and compare the NMR results with the corresponding field data. It is shown that the NMR water saturation after 300 psi centrifugation effectively represents the original water saturation measured by weighing fresh cores. There is a good correlation between mobile water saturation and the water production performance of the corresponding gas wells. The critical mobile water saturation whether reservoir produces water of the Xujiahe low permeability sandstone gas is 6%. The higher the mobile water saturation, the greater the water production rate of gas well. This indicates that well's water production performance can be forecasted by mobile water saturation of cores. (cross-disciplinary physics and related areas of science and technology)

  10. SITE-SCALE SATURATED ZONE TRANSPORT

    International Nuclear Information System (INIS)

    This work provides a site-scale transport model for calculating radionuclide transport in the saturated zone (SZ) at Yucca Mountain, for use in the abstractions model in support of ''Total System Performance Assessment for License Application'' (TSPA-LA). The purpose of this model report is to provide documentation for the components of the site-scale SZ transport model in accordance with administrative procedure AP-SIII.10Q, Models. The initial documentation of this model report was conducted under the ''Technical Work Plan For: Saturated Zone Flow and Transport Modeling and Testing'' (BSC 2003 [DIRS 163965]). The model report has been revised in accordance with the ''Technical Work Plan For: Natural System--Saturated Zone Analysis and Model Report Integration'', Section 2.1.1.4 (BSC 2004 [DIRS 171421]) to incorporate Regulatory Integration Team comments. All activities listed in the technical work plan that are appropriate to the transport model are documented in this report and are described in Section 2.1.1.4 (BSC 2004 [DIRS 171421]). This report documents: (1) the advection-dispersion transport model including matrix diffusion (Sections 6.3 and 6.4); (2) a description and validation of the transport model (Sections 6.3 and 7); (3) the numerical methods for simulating radionuclide transport (Section 6.4); (4) the parameters (sorption coefficient, Kd ) and their uncertainty distributions used for modeling radionuclide sorption (Appendices A and C); (5) the parameters used for modeling colloid-facilitated radionuclide transport (Table 4-1, Section 6.4.2.6, and Appendix B); and (6) alternative conceptual models and their dispositions (Section 6.6). The intended use of this model is to simulate transport in saturated fractured porous rock (double porosity) and alluvium. The particle-tracking method of simulating radionuclide transport is incorporated in the finite-volume heat and mass transfer numerical analysis (FEHM) computer code, (FEHM V2.20, STN: 10086

  11. SITE-SCALE SATURATED ZONE TRANSPORT

    Energy Technology Data Exchange (ETDEWEB)

    S. KELLER

    2004-11-03

    This work provides a site-scale transport model for calculating radionuclide transport in the saturated zone (SZ) at Yucca Mountain, for use in the abstractions model in support of ''Total System Performance Assessment for License Application'' (TSPA-LA). The purpose of this model report is to provide documentation for the components of the site-scale SZ transport model in accordance with administrative procedure AP-SIII.10Q, Models. The initial documentation of this model report was conducted under the ''Technical Work Plan For: Saturated Zone Flow and Transport Modeling and Testing'' (BSC 2003 [DIRS 163965]). The model report has been revised in accordance with the ''Technical Work Plan For: Natural System--Saturated Zone Analysis and Model Report Integration'', Section 2.1.1.4 (BSC 2004 [DIRS 171421]) to incorporate Regulatory Integration Team comments. All activities listed in the technical work plan that are appropriate to the transport model are documented in this report and are described in Section 2.1.1.4 (BSC 2004 [DIRS 171421]). This report documents: (1) the advection-dispersion transport model including matrix diffusion (Sections 6.3 and 6.4); (2) a description and validation of the transport model (Sections 6.3 and 7); (3) the numerical methods for simulating radionuclide transport (Section 6.4); (4) the parameters (sorption coefficient, Kd ) and their uncertainty distributions used for modeling radionuclide sorption (Appendices A and C); (5) the parameters used for modeling colloid-facilitated radionuclide transport (Table 4-1, Section 6.4.2.6, and Appendix B); and (6) alternative conceptual models and their dispositions (Section 6.6). The intended use of this model is to simulate transport in saturated fractured porous rock (double porosity) and alluvium. The particle-tracking method of simulating radionuclide transport is incorporated in the finite-volume heat and mass transfer numerical

  12. Novel application of cyclolipopeptide amphisin: feasibility study as additive to remediate polycyclic aromatic hydrocarbon (PAH) contaminated sediments.

    Science.gov (United States)

    Groboillot, Anne; Portet-Koltalo, Florence; Le Derf, Franck; Feuilloley, Marc J G; Orange, Nicole; Poc, Cécile Duclairoir

    2011-01-01

    To decontaminate dredged harbor sediments by bioremediation or electromigration processes, adding biosurfactants could enhance the bioavailability or mobility of contaminants in an aqueous phase. Pure amphisin from Pseudomonas fluorescens DSS73 displays increased effectiveness in releasing polycyclic aromatic hydrocarbons (PAHs) strongly adsorbed to sediments when compared to a synthetic anionic surfactant. Amphisin production by the bacteria in the natural environment was also considered. DSS73's growth is weakened by three model PAHs above saturation, but amphisin is still produced. Estuarine water feeding the dredged material disposal site of a Norman harbor (France) allows both P. fluorescens DSS73 growth and amphisin production. PMID:21673923

  13. Novel Application of Cyclolipopeptide Amphisin: Feasibility Study as Additive to Remediate Polycyclic Aromatic Hydrocarbon (PAH Contaminated Sediments

    Directory of Open Access Journals (Sweden)

    Anne Groboillot

    2011-03-01

    Full Text Available To decontaminate dredged harbor sediments by bioremediation or electromigration processes, adding biosurfactants could enhance the bioavailability or mobility of contaminants in an aqueous phase. Pure amphisin from Pseudomonas fluorescens DSS73 displays increased effectiveness in releasing polycyclic aromatic hydrocarbons (PAHs strongly adsorbed to sediments when compared to a synthetic anionic surfactant. Amphisin production by the bacteria in the natural environment was also considered. DSS73’s growth is weakened by three model PAHs above saturation, but amphisin is still produced. Estuarine water feeding the dredged material disposal site of a Norman harbor (France allows both P. fluorescens DSS73 growth and amphisin production.

  14. Vertical fluxes of aromatic and aliphatic hydrocarbons in the Northwestern Mediterranean Sea

    International Nuclear Information System (INIS)

    Aliphatic and aromatic hydrocarbon fluxes were measured in time series sediment trap samples at 200 m and at 1000 m depths in the open Northwestern Mediterranean Sea, from December 2000 to July 2002. Averaged fluxes of n-alkanes, UCM and T-PAH35 were 2.96 ± 2.60 μg m-2 d-1, 64 ± 60 μg m-2 d-1 and 0.68 ± 0.59 μg m-2 d-1, respectively. Molecular compositions of both hydrocarbon classes showed a contamination in petrogenic hydrocarbons well above the background levels of such an open site, whereas pyrolytic hydrocarbons stand in the range of other open Mediterranean locations. Fluxes displayed ample interannual and seasonal variabilities, mainly related to mass flux variation while concentration evolutions trigger secondary changes in pollutant fluxes. High lithogenic flux events exported particles with a larger pollutant load than biogenic particles formed during the spring bloom and during the summer. Sinking hydrocarbons were efficiently transported from 200 m to 1000 m. - Highlights: → PAH composition, plots of diagnostic PAH ratios and the UCM abundance indicate that non aromatic and aromatic hydrocarbons in sinking particles in the Ligurian Sea were mainly of petrogenic origin. → Fluxes of T-PAH35, n-alkanes and UCM transported downward at 200 m during the year 2001 were 269, 1218 and 26 910 mg m-2 yr-1, respectively. → Vertical fluxes of aliphatic and aromatic hydrocarbons displayed ample seasonal and inter-annual variabilities, mainly related to mass flux variation. Concentration variation triggered smaller changes in pollutant fluxes. → High fluxes of lithogenic particles occurring from early January to early March 2001 transported about 45% of the annual vertical export of contaminants. In April-May, high fluxes of biogenic particles also transported a significant fraction of pollutants, despite the dilution of petrogenic and pyrolytic PAHs by biogenic material. - Vertical fluxes of aliphatic and aromatic hydrocarbons in the Ligurian Sea show

  15. Vertical fluxes of aromatic and aliphatic hydrocarbons in the Northwestern Mediterranean Sea

    Energy Technology Data Exchange (ETDEWEB)

    Deyme, Remi; Bouloubassi, Ioanna; Taphanel-Valt, Marie-Helene [Laboratoire d' Oceanographie et du Climat, Experimentation et Approches Numeriques (LOCEAN/IPSL), Universite Pierre et Marie Curie-CNRS-IRD-MNHN, UMR 7159, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Miquel, Juan-Carlos [Environment Laboratories, International Atomic Energy Agency, 4 Quai Antoine 1er, MC98000 Monaco, Principality of Monaco (Monaco); Lorre, Anne [Laboratoire d' Oceanographie et du Climat, Experimentation et Approches Numeriques (LOCEAN/IPSL), Universite Pierre et Marie Curie-CNRS-IRD-MNHN, UMR 7159, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Marty, Jean-Claude [CNRS- Universite Pierre et Marie Curie, UMR 7093, LOV, Observatoire oceanographique, 06234 Villefranche/mer (France); Mejanelle, Laurence, E-mail: laurence.mejanelle@upmc.fr [Laboratoire d' ECObiogeochimie Benthique, FRE3350, CNRS-Universite Pierre et Marie Curie, Avenue du Fontaule, 66650 Banyuls Sur Mer (France)

    2011-12-15

    Aliphatic and aromatic hydrocarbon fluxes were measured in time series sediment trap samples at 200 m and at 1000 m depths in the open Northwestern Mediterranean Sea, from December 2000 to July 2002. Averaged fluxes of n-alkanes, UCM and T-PAH{sub 35} were 2.96 {+-} 2.60 {mu}g m{sup -2} d{sup -1}, 64 {+-} 60 {mu}g m{sup -2} d{sup -1} and 0.68 {+-} 0.59 {mu}g m{sup -2} d{sup -1}, respectively. Molecular compositions of both hydrocarbon classes showed a contamination in petrogenic hydrocarbons well above the background levels of such an open site, whereas pyrolytic hydrocarbons stand in the range of other open Mediterranean locations. Fluxes displayed ample interannual and seasonal variabilities, mainly related to mass flux variation while concentration evolutions trigger secondary changes in pollutant fluxes. High lithogenic flux events exported particles with a larger pollutant load than biogenic particles formed during the spring bloom and during the summer. Sinking hydrocarbons were efficiently transported from 200 m to 1000 m. - Highlights: > PAH composition, plots of diagnostic PAH ratios and the UCM abundance indicate that non aromatic and aromatic hydrocarbons in sinking particles in the Ligurian Sea were mainly of petrogenic origin. > Fluxes of T-PAH35, n-alkanes and UCM transported downward at 200 m during the year 2001 were 269, 1218 and 26 910 mg m{sup -2} yr{sup -1}, respectively. > Vertical fluxes of aliphatic and aromatic hydrocarbons displayed ample seasonal and inter-annual variabilities, mainly related to mass flux variation. Concentration variation triggered smaller changes in pollutant fluxes. > High fluxes of lithogenic particles occurring from early January to early March 2001 transported about 45% of the annual vertical export of contaminants. In April-May, high fluxes of biogenic particles also transported a significant fraction of pollutants, despite the dilution of petrogenic and pyrolytic PAHs by biogenic material. - Vertical fluxes of

  16. The Design of Reactions, Catalysts and Materials with Aromatic Ions

    Science.gov (United States)

    Bandar, Jeffrey Scott

    This thesis details the use of aromatic ions, especially aminocyclopropenium ions, as empowering design elements in the development of new chemical reactions, organic catalysts and polymeric materials. A particular focus is placed throughout on understanding the relationship between the structure of aromatic ions and their performance in these novel applications. Additionally, the benefits that aromatic ions provide in these contexts are highlighted. The first chapter briefly summarizes the Lambert Group's prior efforts toward exploiting the unique reactivity profiles of aromatic ions in the context of new reaction design. Also provided in the first chapter is a comprehensive literature review of aminocyclopropenium ions, upon which the majority of advances described in this thesis are based. To set the stage for the first application of aminocyclopropenium ions, Chapter 2 provides an account of existing highly Bronsted basic functional groups, including guanidines, proazaphosphatranes and iminophosphoranes. The provided review on the synthesis and use in asymmetric catalysis of these bases indicates that there is a high need for conceptually new Bronsted basic functional groups. To address this need, the development of chiral 2,3-bis(dialkylamino)cyclopropenimines as a new platform for asymmetric Bronsted base catalysis is described in Chapter 3. This new class of Bronsted base is readily synthesized on scale, operates efficiently under practical conditions, and greatly outperforms closely related guanidine-based catalysts. Structure-activity relationship studies, mechanistic experiments and computational transition state modeling are all discussed in the context of asymmetric glycinate imine Michael reactions in order to arrive at a working model for cyclopropenimine chemistry. Cumulatively, this chapter provides a "user's guide" to understanding and developing further applications of 2,3-bis(dialkylamino)cyclopropenimines. The use of our optimal chiral 2,3-bis

  17. Asymmetric Wave Propagation Through Saturable Nonlinear Oligomers

    Directory of Open Access Journals (Sweden)

    Daniel Law

    2014-10-01

    Full Text Available In the present paper we consider nonlinear dimers and trimers (more generally, oligomers embedded within a linear Schrödinger lattice where the nonlinear sites are of saturable type. We examine the stationary states of such chains in the form of plane waves, and analytically compute their reflection and transmission coefficients through the nonlinear oligomer, as well as the corresponding rectification factors which clearly illustrate the asymmetry between left and right propagation in such systems. We examine not only the existence but also the dynamical stability of the plane wave states. Lastly, we generalize our numerical considerations to the more physically relevant case of Gaussian initial wavepackets and confirm that the asymmetry in the transmission properties also persists in the case of such wavepackets.

  18. Gamma irradiation in a saturated tuff environment

    International Nuclear Information System (INIS)

    The influence of gamma irradiation on the reaction of actinide doped SRL 165 and PNL 76-68 glasses in a saturated tuff environment has been studied in a series of tests lasting up to 56 days. The reaction, and subsequent actinide release, of both glasses depends on the dynamic interaction between radiolysis effects which cause the solution pH to become more acidic and glass reaction which drives the pH more basic. The use of large gamma irradiation dose rates to accelerate reactions that would occur in an actual repository radiation field may affect this dynamic balance by unduly influencing the mechanism of the glass-water reaction. Comparisons are made between the present results and data obtained by reacting the same or similar glasses using MCC-1 and NNWSI rock cup procedures. 11 references, 3 figures

  19. Convection of Moist Saturated Air: Analytical Study

    Directory of Open Access Journals (Sweden)

    Robert Zakinyan

    2016-01-01

    Full Text Available In the present work, the steady-state stationary thermal convection of moist saturated air in a lower atmosphere has been studied theoretically. Thermal convection was considered without accounting for the Coriolis force, and with only the vertical temperature gradient. The analytical solution of geophysical fluid dynamics equations, which generalizes the formulation of the moist convection problem, is obtained in the two-dimensional case. The stream function is derived in the Boussinesq approximation with velocity divergence taken as zero. It has been shown that the stream function is asymmetrical in vertical direction contrary to the dry and moist unsaturated air convection. It has been demonstrated that the convection in moist atmosphere strongly depends on the vapor mass fraction gradient.

  20. Nonlinear saturation of stimulated diffusion scattering

    International Nuclear Information System (INIS)

    A nonlinear instability theory is presented for stimulated scattering of electromagnetic ordinary-mode radiation from electrostatic ''diffusion modes.'' These ''diffusion modes'' are excited unstable by the incident radiation, and have their linear damping rates proportional to the diffusion tensor. Two diffusion modes are found; one corresponds to thermal diffusion and the other to particle diffusion. The thermal diffusion mode was previously calculated by Berger, Goldman, and DuBois for a two-dimensional model. The present calculation is made for three dimensions to show that the radiation is scattered over a wide angle in the plane perpendicular to a uniform magnetic field. A three-dimensional model is necessary to determine nonlienar effects. The saturated level of the electrostatic diffusion modes is calculated explicitly. For ionospheric modification experiments it is found that the electron density fluctuations are almost 1% of the ambient electron density

  1. Terahertz Saturable Absorption in Superconducting Metamaterials

    CERN Document Server

    Keiser, George R; Zhao, Xiaoguang; Zhang, Xin; Averitt, Richard D

    2016-01-01

    We present a superconducting metamaterial saturable absorber at terahertz frequencies. The absorber consists of an array of split ring resonators (SRRs) etched from a 100nm YBaCu3O7 (YBCO) film. A polyimide spacer layer and gold ground plane are deposited above the SRRs, creating a reflecting perfect absorber. Increasing either the temperature or incident electric field (E) decreases the superconducting condensate density and corresponding kinetic inductance of the SRRs. This alters the impedance matching in the metamaterial, reducing the peak absorption. At low electric fields, the absorption was optimized near 80% at T=10K and decreased to 20% at T=70K. For E=40kV/cm and T=10K, the peak absorption was 70% decreasing to 40% at 200kV/cm, corresponding to a modulation of 43%.

  2. Equatorial trench at the magnetopause under saturation

    CERN Document Server

    Dmitriev, A; 10.1029/2012JA017834

    2013-01-01

    Magnetic data from GOES geosynchronous satellites were applied for statistical study of the low-latitude dayside magnetopause under a strong interplanetary magnetic field of southward orientation when the reconnection at the magnetopause was saturated. From minimum variance analysis, we determined the magnetopause orientation and compared it with predictions of a reference model. The magnetopause shape was found to be substantially distorted by a duskward shifting such that the nose region appeared in the postnoon sector. At equatorial latitudes, the shape of magnetopause was characterized by a prominent bluntness and by a trench formed in the postnoon sector. The origin of distortions was regarded in the context of the storm-time magnetospheric currents and the large-scale quasi-state reconnection at the dayside magnetopause.

  3. From QCD to nuclear matter saturation

    International Nuclear Information System (INIS)

    We discuss a relativistic chiral theory of nuclear matter with σ and ω exchange using a formulation of the σ model in which all the chiral constraints are automatically fulfilled. We establish a relation between the nuclear response to the scalar field and the QCD one which includes the nucleonic parts. It allows a comparison between nuclear and QCD information. Going beyond the mean field approach we introduce the effects of the pion loops supplemented by the short-range interaction. The corresponding Landau-Migdal parameters are taken from spin-isospin physics results. The parameters linked to the scalar meson exchange are extracted from lattice QCD results. These inputs lead to a reasonable description of the saturation properties, illustrating the link between QCD and nuclear physics. We also derive from the corresponding equation of state the density dependence of the quark condensate and of the QCD susceptibilities. (authors)

  4. Aromatic plant production on metal contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Zheljazkov, Valtcho D. [Mississippi State, Department of Plant and Soil Sciences and North Mississippi Research and Extension Center, 5421 Highway 145 South, Verona, MS 38879 (United States)], E-mail: vj40@pss.msstate.edu; Craker, Lyle E.; Xing Baoshan [Department of Plant and Soil Sciences, 12 Stockbridge Hall, University of Massachusetts, Amherst, MA 01003 (United States); Nielsen, Niels E. [Plant Nutrition and Soil Fertility Lab, Department of Agricultural Sciences, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK1871, Copenhagen (Denmark); Wilcox, Andrew [Harper Adams University College, Newport, Shropshire, TF10 8NB (United Kingdom)

    2008-06-01

    Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha{sup -1} for Cd, 660 g ha{sup -1} for Pb, 180 g ha{sup -1} for Cu, 350 g ha{sup -1} for Mn, and 205 g ha{sup -1} for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (< 1 {mu}m) particles, although there were larger particles (1-5 {mu}m) with high concentrations of individual metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil.

  5. Aromatic plant production on metal contaminated soils

    International Nuclear Information System (INIS)

    Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha-1 for Cd, 660 g ha-1 for Pb, 180 g ha-1 for Cu, 350 g ha-1 for Mn, and 205 g ha-1 for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (< 1 μm) particles, although there were larger particles (1-5 μm) with high concentrations of individual metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil

  6. Biosynthesis of the Aromatic Amino Acids.

    Science.gov (United States)

    Pittard, James; Yang, Ji

    2008-09-01

    This chapter describes in detail the genes and proteins of Escherichia coli involved in the biosynthesis and transport of the three aromatic amino acids tyrosine, phenylalanine, and tryptophan. It provides a historical perspective on the elaboration of the various reactions of the common pathway converting erythrose-4-phosphate and phosphoenolpyruvate to chorismate and those of the three terminal pathways converting chorismate to phenylalanine, tyrosine, and tryptophan. The regulation of key reactions by feedback inhibition, attenuation, repression, and activation are also discussed. Two regulatory proteins, TrpR (108 amino acids) and TyrR (513 amino acids), play a major role in transcriptional regulation. The TrpR protein functions only as a dimer which, in the presence of tryptophan, represses the expression of trp operon plus four other genes (the TrpR regulon). The TyrR protein, which can function both as a dimer and as a hexamer, regulates the expression of nine genes constituting the TyrR regulon. TyrR can bind each of the three aromatic amino acids and ATP and under their influence can act as a repressor or activator of gene expression. The various domains of this protein involved in binding the aromatic amino acids and ATP, recognizing DNA binding sites, interacting with the alpha subunit of RNA polymerase, and changing from a monomer to a dimer or a hexamer are all described. There is also an analysis of the various strategies which allow TyrR in conjunction with particular amino acids to differentially affect the expression of individual genes of the TyrR regulon. PMID:26443741

  7. Biodegradation Rates of Aromatic Contaminants in Biofilm Reactors

    DEFF Research Database (Denmark)

    Arcangeli, Jean-Pierre; Arvin, Erik

    1995-01-01

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

  8. Critical analysis of the local aromaticity concept in polyaromatic hydrocarbons.

    Science.gov (United States)

    Bultinck, Patrick

    2007-01-01

    A large number of local aromaticity indices for the benzenoid rings in polyaromatic hydrocarbons is computed. The results are interpreted, supporting Clar's hypothesis, and mutual correlations are investigated. It is shown that there are good correlations between all indices that strictly allow comparing benzenoid character. Poor correlations are found with NICS. A rationale is offered, yielding the conclusion that NICS and ring current maps follow a fundamentally different path to local aromaticity. In this sense the lack of correlation is not due to a real multidimensional character of aromaticity but rather to confusion and vagueness of the aromaticity concept. PMID:17328438

  9. Aromatic compounds from three Brazilian Lauraceae species

    Directory of Open Access Journals (Sweden)

    Andrea Nastri de Luca Batista

    2010-01-01

    Full Text Available Phytochemical investigations on three Brazilian Lauraceae species from the Cerrado region of São Paulo State, Ocotea corymbosa (Meins Mez., O. elegans Mez. and Persea pyrifolia Nees & Mart. ex Nees resulted in the isolation of flavonoids, an ester of the 4-O-E-caffeoylquinic acid, an aromatic sesquiterpene besides furofuran lignans. This is the first chemical study on the leaves of Ocotea elegans and O. corymbosa as well as the first report of non-volatile compounds from Persea pyrifolia.

  10. Carcinogenic potential of hydrotreated petroleum aromatic extracts.

    Science.gov (United States)

    Doak, S M; Hend, R W; van der Wiel, A; Hunt, P F

    1985-06-01

    Five experimental petroleum extracts were produced from luboil distillates derived from Middle East paraffinic crude by solvent extraction and severe hydrotreatment. The polycyclic aromatic content (PCA) of the extracts was determined by dimethyl sulphoxide extraction and ranged from 3.7-9.2% w/w. The five extracts were evaluated for their potential to induce cutaneous and systemic neoplasia in female mice derived from Carworth Farm No 1 strain (CF1). The test substances were applied undiluted (0.2 ml per application) to the shorn dorsal skin twice weekly for up to 78 weeks, with 48 mice in each treatment group and 96 in the untreated control group; two further groups, each of 48 mice, were similarly treated either with a non-hydrotreated commercial aromatic extract (PCA content, 19.7% w/v) or with a low dose of benzo(a)pyrene (12.5 micrograms/ml acetone). The mice were housed individually in polypropylene cages in specified pathogen free conditions. The incidence of cutaneous and systemic tumours was determined from histological analysis of haematoxylin and eosin stained tissue sections. The results were correlated with the PCA content of the extracts and compared with those from female mice exposed to a non-hydrotreated commercial aromatic extract. Four of the hydrotreated extracts were carcinogenic for murine skin; the two products with the lower PCA contents were less carcinogenic than the products with the higher PCA contents and all were less carcinogenic than the commercial extract. One extract with the lowest PCA content was non-carcinogenic. Thus refining by severe hydrotreatment was an effective method of reducing the carcinogenic potential of petroleum aromatic extracts. Although other physicochemical properties may influence the biological activity of oil products, the PCA content determined by dimethyl sulphoxide extraction may be a useful indicator of the potential of oil products to induce cutaneous tumours in experimental animals. There was no

  11. Aromatics oxidation and soot formation in flames

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-12-01

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and soot and fullerenes formation in flames. The scope includes detailed measurements of profiles of stable and radical species concentrations in low-pressure one-dimensional premixed flames. Intermediate species identifications and mole fractions, fluxes, and net reaction rates calculated from the measured profiles are used to test postulated reaction mechanisms. Particular objectives are to identify and to determine or confirm rate constants for the main benzene oxidation reactions in flames, and to characterize fullerenes and their formation mechanisms and kinetics.

  12. Photoinduced dynamics in protonated aromatic amino acid

    CERN Document Server

    Grégoire, Gilles; Barat, Michel; Fayeton, Jacqueline; Dedonder-Lardeux, Claude; Jouvet, Christophe

    2008-01-01

    UV photoinduced fragmentation of protonated aromatics amino acids have emerged the last few years, coming from a situation where nothing was known to what we think a good understanding of the optical properties. We will mainly focus this review on the tryptophan case. Three groups have mostly done spectroscopic studies and one has mainly been involved in dynamics studies of the excited states in the femtosecond/picosecond range and also in the fragmentation kinetics from nanosecond to millisecond. All these data, along with high level ab initio calculations, have shed light on the role of the different electronic states of the protonated molecules upon the fragmentation mechanisms.

  13. Studies on the adsorption of sulfo-group-containing aromatics by chitosan-β-cyclodextrin.

    Science.gov (United States)

    Shi, Wenjian; Chen, Shuwei; Chang, Fei; Han, Yue; Zhang, Yuanzhang

    2012-01-01

    Chitosan-β-cyclodextrin (CTS-CD) prepared through a crosslinking reaction between chitosan and β-cyclodextrin was employed to adsorb the three following sulfo-group-containing aromatics: disodium 2-naphthol-3,6-disulfonate (R salt), 2-naphthalene sulfonic acid (NSA), and sodium dodecylbenzene sulfonate (SDBS). At 318 K, the saturated adsorption capacity of CTS-CD for R salt, NSA, and SDBS was 431, 416, and 376 mg/g, respectively. The experimental data fitted the second-order model well and the rate constant of the adsorption increased with the temperature increment. The values of apparent activation energy for R salt, NSA, and SDBS were calculated as 33.2, 34.2, and 16.8 kJ/mol respectively. The isothermal adsorption was found following the Langmuir adsorption equation. The negative values of ΔG and the positive values of ΔH indicated that the adsorption process was spontaneous and exothermic. PMID:22339013

  14. Sulfur tolerant zeolite supported platinum catalysts for aromatics hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Bergem, Haakon

    1997-12-31

    The increased demand for transportation fuels at the expence of heavier fuel oil has forced the refinery industry to expand their conversion capacity with hydrotreating as one of the key processes. A shift towards more diesel powered vehicles along with tightening fuel regulations demanding cleaner fuels has lead to increasing interest in catalytic processes for the manufacturing of such environmentally acceptable fuels. This provides the motivation for this thesis. Its main objective was to study possible catalysts active for desulfurization, hydrogenation, and ring-opening of aromatics all in the presence of sulfur. A close examination of the physical properties and kinetical behaviour of the chosen catalysts has been performed. A high pressure reactor setup was designed and built for activity measurements. Zeolite supported platinum catalysts were prepared and both the metal and acid functions were characterized utilizing various experimental techniques. Hydrogenation of toluene was used as a model reaction and the effect of sulfur adsorption on the activity and kinetic behaviour of the catalysts was investigated. The catalyst samples showed hydrogenation activities comparable to a commercial Pt/Al2O3 catalyst. There were no clear differences in the effect of the various sulfur compounds studied. Platinum supported on zeolite Y gave considerably more sulfur tolerant catalysts compared to Al2O3 as support. 155 refs., 58 figs., 36 tabs.

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

    OpenAIRE

    Yang, Kaijie; Chen, Baoliang; Zhu, Lizhong

    2015-01-01

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

  16. Tracking Controller for Intrinsic Output Saturated Systems in Presence of Amplitude and Rate Input Saturations

    DEFF Research Database (Denmark)

    Chater, E.; Giri, F.; Guerrero, Josep M.;

    2014-01-01

    We consider the problem of controlling plants that are subject to multiple saturation constraints. Especially, we are interested in linear systems whose input is subject to amplitude and rate constraints of saturation type. Furthermore, the considered systems output is also subject to an intrinsic......-loop control system is analyzed using input-output stability tools. Thus, conditions guaranteeing l2-tracking performances are formally defined. Interestingly, the proposed controller is shown to ensure perfect output-reference tracking in presence of varying with l2-vanishing rate inputs. On the other hand......, in the case of arbitrary inputs, the proposed controller guarantees that the less changing the inputs are the better the output-reference tracking....

  17. An Aromatic Inventory of the Local Volume

    CERN Document Server

    Marble, A R; van Zee, L; Dale, D A; Smith, J D T; Gordon, K D; Wu, Y; Lee, J C; Kennicutt, R C; Skillman, E D; Johnson, L C; Block, M; Calzetti, D; Cohen, S A; Lee, H; Schuster, M D

    2010-01-01

    Using infrared photometry from the Spitzer Space Telescope, we perform the first inventory of aromatic feature emission (AFE, but also commonly referred to as PAH emission) for a statistically complete sample of star-forming galaxies in the local volume. The photometric methodology involved is calibrated and demonstrated to recover the aromatic fraction of the IRAC 8 micron flux with a standard deviation of 6% for a training set of 40 SINGS galaxies (ranging from stellar to dust dominated) with both suitable mid-infrared Spitzer IRS spectra and equivalent photometry. A potential factor of two improvement could be realized with suitable 5.5 and 10 micron photometry, such as what may be provided in the future by JWST. The resulting technique is then applied to mid-infrared photometry for the 258 galaxies from the Local Volume Legacy (LVL) survey, a large sample dominated in number by low-luminosity dwarf galaxies for which obtaining comparable mid-infrared spectroscopy is not feasible. We find the total LVL lum...

  18. Molecular dynamics studies of aromatic hydrocarbon liquids

    International Nuclear Information System (INIS)

    This project mainly involves a molecular dynamics and Monte Carlo study of the effect of molecular shape on thermophysical properties of bulk fluids with an emphasis on the aromatic hydrocarbon liquids. In this regard we have studied the modeling, simulation methodologies, and predictive and correlating methods for thermodynamic properties of fluids of nonspherical molecules. In connection with modeling we have studied the use of anisotropic site-site potentials, through a modification of the Gay-Berne Gaussian overlap potential, to successfully model the aromatic rings after adding the necessary electrostatic moments. We have also shown these interaction sites should be located at the geometric centers of the chemical groups. In connection with predictive methods, we have shown two perturbation type theories to work well for fluids modeled using one-center anisotropic potentials and the possibility exists for extending these to anisotropic site-site models. In connection with correlation methods, we have studied, through simulations, the effect of molecular shape on the attraction term in the generalized van der Waals equation of state for fluids of nonspherical molecules and proposed a possible form which is to be studied further. We have successfully studied the vector and parallel processing aspects of molecular simulations for fluids of nonspherical molecules

  19. Saturated phosphatidic acids mediate saturated fatty acid–induced vascular calcification and lipotoxicity

    OpenAIRE

    Masuda, Masashi; Miyazaki-Anzai, Shinobu; Audrey L Keenan; Okamura, Kayo; Kendrick, Jessica; Chonchol, Michel; Offermanns, Stefan; James M. Ntambi; Kuro-o, Makoto; Miyazaki, Makoto

    2015-01-01

    Recent evidence indicates that saturated fatty acid–induced (SFA-induced) lipotoxicity contributes to the pathogenesis of cardiovascular and metabolic diseases; however, the molecular mechanisms that underlie SFA-induced lipotoxicity remain unclear. Here, we have shown that repression of stearoyl-CoA desaturase (SCD) enzymes, which regulate the intracellular balance of SFAs and unsaturated FAs, and the subsequent accumulation of SFAs in vascular smooth muscle cells (VSMCs), are characteristic...

  20. Protocol for the development of the Master Chemical Mechanism, MCM v3 (Part B: tropospheric degradation of aromatic volatile organic compounds

    Directory of Open Access Journals (Sweden)

    M. E. Jenkin

    2002-11-01

    Full Text Available Kinetic and mechanistic data relevant to the tropospheric degradation of aromatic volatile organic compounds (VOC have been used to define a mechanism development protocol, which has been used to construct degradation schemes for 18 aromatic VOC as part of version 3 of the Master Chemical Mechanism (MCM v3. This is complementary to the treatment of 107 non-aromatic VOC, presented in a companion paper. The protocol is divided into a series of subsections describing initiation reactions, the degradation chemistry to first generation products via a number of competitive routes, and the further degradation of first and subsequent generation products. Emphasis is placed on describing where the treatment differs from that applied to the non-aromatic VOC. The protocol is based on work available in the open literature up to the beginning of 2001, and some other studies known by the authors which were under review at the time. Photochemical Ozone Creation Potentials (POCP have been calculated for the 18 aromatic VOC in MCM v3 for idealised conditions appropriate to north-west Europe, using a photochemical trajectory model. The POCP values provide a measure of the relative ozone forming abilities of the VOC. These show distinct differences from POCP values calculated previously for the aromatics, using earlier versions of the MCM, and reasons for these differences are discussed.

  1. Protocol for the development of the Master Chemical Mechanism, MCM v3 (Part B: tropospheric degradation of aromatic volatile organic compounds

    Directory of Open Access Journals (Sweden)

    M. E. Jenkin

    2003-01-01

    Full Text Available Kinetic and mechanistic data relevant to the tropospheric degradation of aromatic volatile organic compounds (VOC have been used to define a mechanism development protocol, which has been used to construct degradation schemes for 18 aromatic VOC as part of version 3 of the Master Chemical Mechanism (MCM v3. This is complementary to the treatment of 107 non-aromatic VOC, presented in a companion paper. The protocol is divided into a series of subsections describing initiation reactions, the degradation chemistry to first generation products via a number of competitive routes, and the further degradation of first and subsequent generation products. Emphasis is placed on describing where the treatment differs from that applied to the non-aromatic VOC. The protocol is based on work available in the open literature up to the beginning of 2001, and some other studies known by the authors which were under review at the time. Photochemical Ozone Creation Potentials (POCP have been calculated for the 18 aromatic VOC in MCM v3 for idealised conditions appropriate to north-west Europe, using a photochemical trajectory model. The POCP values provide a measure of the relative ozone forming abilities of the VOC. These show distinct differences from POCP values calculated previously for the aromatics, using earlier versions of the MCM, and reasons for these differences are discussed.

  2. SATURATED ZONE FLOW AND TRANSPORT MODEL ABSTRACTION

    Energy Technology Data Exchange (ETDEWEB)

    B.W. ARNOLD

    2004-10-27

    The purpose of the saturated zone (SZ) flow and transport model abstraction task is to provide radionuclide-transport simulation results for use in the total system performance assessment (TSPA) for license application (LA) calculations. This task includes assessment of uncertainty in parameters that pertain to both groundwater flow and radionuclide transport in the models used for this purpose. This model report documents the following: (1) The SZ transport abstraction model, which consists of a set of radionuclide breakthrough curves at the accessible environment for use in the TSPA-LA simulations of radionuclide releases into the biosphere. These radionuclide breakthrough curves contain information on radionuclide-transport times through the SZ. (2) The SZ one-dimensional (I-D) transport model, which is incorporated in the TSPA-LA model to simulate the transport, decay, and ingrowth of radionuclide decay chains in the SZ. (3) The analysis of uncertainty in groundwater-flow and radionuclide-transport input parameters for the SZ transport abstraction model and the SZ 1-D transport model. (4) The analysis of the background concentration of alpha-emitting species in the groundwater of the SZ.

  3. Neutron logging in partially saturated media

    International Nuclear Information System (INIS)

    At the Lawrence Livermore Laboratory the behavior of epithermal neutron logging equipment in large holes in partially saturated alluvium and in ashfall and ashflow tuff is being studied. Monte Carlo neutron transport calculations indicate that the number of epithermal neutrons from either a fission or 14-MeV source depends not only on the water content of the medium, but also on its bulk density. Curves as functions of both parameters have been developed and an interpolation method devised. Attempts to calibrate neutron logs by comparing log-measured water content with water content from cores result in unacceptably large errors. Part of the error is due to the fact that commercial neutron logs are quite sensitive to hold size variations. It is shown that with proper shielding the hole size effect can be eliminated. An effort is in progress to study the two water contents, bulk density, and material type in a number of holes to determine whether core data calibration would be satisfactory with proper corrections

  4. Saturated output tabletop x-ray lasers

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, J; Osterheld, A L; Nilsen, J; Hunter, J R; Li, Y; Faenov, A Ya; Pikuz, T A; Shlyaptsev, N

    2000-12-01

    The high efficiency method of transient collisional excitation has been successfully demonstrated for Ne-like and Ni-like ion x-ray laser schemes with small 5-10 J laser facilities. Our recent studies using the tabletop COMET (Compact Multipulse Terawatt) laser system at the Lawrence Livermore National Laboratory (LLNL) have produced several x-ray lasers operating in the saturation regime. Output energy of 10-15 {micro}J corresponding to a gL product of 18 has been achieved on the Ni-like Pd 4d {yields} 4p transition at 147 {angstrom} with a total energy of 5-7 J in a 600 ps pulse followed by a 1.2 ps pulse. Analysis of the laser beam angular profile indicates that refraction plays an important role in the amplification and propagation process in the plasma column. We report further improvement in the extraction efficiency by varying a number of laser driver parameters. In particular, the duration of the second short pulse producing the inversion has an observed effect on the x-ray laser output.

  5. SATURATED ZONE FLOW AND TRANSPORT MODEL ABSTRACTION

    International Nuclear Information System (INIS)

    The purpose of the saturated zone (SZ) flow and transport model abstraction task is to provide radionuclide-transport simulation results for use in the total system performance assessment (TSPA) for license application (LA) calculations. This task includes assessment of uncertainty in parameters that pertain to both groundwater flow and radionuclide transport in the models used for this purpose. This model report documents the following: (1) The SZ transport abstraction model, which consists of a set of radionuclide breakthrough curves at the accessible environment for use in the TSPA-LA simulations of radionuclide releases into the biosphere. These radionuclide breakthrough curves contain information on radionuclide-transport times through the SZ. (2) The SZ one-dimensional (I-D) transport model, which is incorporated in the TSPA-LA model to simulate the transport, decay, and ingrowth of radionuclide decay chains in the SZ. (3) The analysis of uncertainty in groundwater-flow and radionuclide-transport input parameters for the SZ transport abstraction model and the SZ 1-D transport model. (4) The analysis of the background concentration of alpha-emitting species in the groundwater of the SZ

  6. Cyclic Shearing Deformation Behavior of Saturated Clays

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The apparatus for static and dynamic universal triaxial and torsional shear soil testing is employed to perform stress-controlled cyclic single-direction torsional shear tests and two-direction coupled shear tests under unconsolidated-undrained conditions. Through a series of tests on saturated clay, the effects of initial shear stress and stress reversal on the clay's strain-stress behavior are examined, and the behavior of pore water pressure is studied. The experimental results indicate that the patterns of stress-strain relations are distinctly influenced by the initial shear stress in the cyclic single-direction shear tests. When the initial shear stress is large and no stress reversal occurs, the predominant deformation behavior is characterized by an accumulative effect. When the initial shear stress is zero and symmetrical cyclic stress occurs, the predominant deformation behavior is characterized by a cyclic effect. The pore water pressure fluctuates around the confining pressure with the increase of cycle number. It seems that the fluctuating amplitude increases with the increase of the cyclic stress. But a buildup of pore water pressure does not occur. The deformations of clay samples under the complex initial and the cyclic coupled stress conditions include the normal deviatoric deformation and horizontal shear deformation, the average deformation and cyclic deformation. A general strain failure criterion taking into account these deformations is recommended and is proved more stable and suitable compared to the strain failure criteria currently used.

  7. Saturation of Alfven modes in tokamaks

    Science.gov (United States)

    White, Roscoe; Gorelenkov, Nikolai; Gorelenkova, Marina; Podesta, Mario; Chen, Yang

    2015-11-01

    The effect of Alfven modes on high energetic particles in tokamaks is important in general, and could be of significance for ITER. This work is a combination of analytic models and numerical simulation to find the saturation levels of unstable Alfven modes and the resulting effect on beam and alpha particle distributions. Solving the drift kinetic equation with a guiding center code in the presence of Alfven modes driven unstable by a distribution of high energy particles requires the use of a δf formalism, wherby the initial distribution f0 is assumed to be a steady state high energy particle distribution in the absense of the modes, and f =f0 + δf describes the particle distribution in the presence of the modes. The Hamiltonian is written as H =H0 +H1 with H0 giving the unperturbed motion, conserving particle energy E, toroidal canonical momentum Pζ, and magnetic moment μ. By writing the initial particle distribution in terms of these variables, a simple means of calculating mode-particle energy and momentum transfer results, giving a very accurate δf formalism.

  8. Metal saturation in the upper mantle.

    Science.gov (United States)

    Rohrbach, Arno; Ballhaus, Chris; Golla-Schindler, Ute; Ulmer, Peter; Kamenetsky, Vadim S; Kuzmin, Dmitry V

    2007-09-27

    The oxygen fugacity f(O2)of the Earth's mantle is one of the fundamental variables in mantle petrology. Through ferric-ferrous iron and carbon-hydrogen-oxygen equilibria, f(O2) influences the pressure-temperature positions of mantle solidi and compositions of small-degree mantle melts. Among other parameters, f(O2) affects the water storage capacity and rheology of the mantle. The uppermost mantle, as represented by samples and partial melts, is sufficiently oxidized to sustain volatiles, such as H2O and CO2, as well as carbonatitic melts, but it is not known whether the shallow mantle is representative of the entire upper mantle. Using high-pressure experiments, we show here that large parts of the asthenosphere are likely to be metal-saturated. We found that pyroxene and garnet synthesized at >7 GPa in equilibrium with metallic Fe can incorporate sufficient ferric iron that the mantle at >250 km depth is so reduced that an (Fe,Ni)-metal phase may be stable. Our results indicate that the oxidized nature of the upper mantle can no longer be regarded as being representative for the Earth's upper mantle as a whole and instead that oxidation is a shallow phenomenon restricted to an upper veneer only about 250 km in thickness. PMID:17898766

  9. Saturated Zone Denitrification at California Dairies

    International Nuclear Information System (INIS)

    Denitrification can effectively mitigate the problem of high nitrate concentrations in groundwater under dairy operations by reducing nitrate to N2 gas, at sites where biogeochemical conditions are favorable. We present results from field studies at central California dairies that document the occurrence of saturated-zone denitrification in shallow groundwater using biomolecular indicators, stable isotope compositions of nitrate, and measurements of dissolved excess N2 gas. Excess N2 concentrations provide a measure of the extent to which nitrate in groundwater has been partially or completely denitrified. Abundant excess N2 and young 3H/3He apparent groundwater ages indicate high denitrification rates near manure lagoons where multiple lines of evidence indicate seepage of lagoon water into the groundwater system. Natural tracers of lagoon water include high chloride and dissolved organic carbon concentrations, distinctive trace organic compounds, and high groundwater (delta)18O values (relative to other recharge sources). Proximal to the lagoons, NH4+ may be present in groundwater, but is strongly adsorbed on to sediment particles. Bubble formation in the lagoons causes the exsolution of other gases (N2, Ar, Ne, He, etc.), which partition into the gas phase and strip the lagoon water of its dissolved gas load, providing a unique tracer of lagoon seepage in groundwater

  10. Magnetic Field Saturation in the Riga Dynamo Experiment

    CERN Document Server

    Gailitis, A; Platacis, E; Dementev, S; Cifersons, A; Gerbeth, G; Gundrum, T; Stefani, F; Christen, M; Will, G; Gailitis, Agris; Lielausis, Olgerts; Platacis, Ernests; Dement'ev, Sergej; Cifersons, Arnis; Gerbeth, Gunter; Gundrum, Thomas; Stefani, Frank; Christen, Michael; Will, Gotthard

    2001-01-01

    After the dynamo experiment in November 1999 had shown magnetic field self-excitation in a spiraling liquid metal flow, in a second series of experiments emphasis was placed on the magnetic field saturation regime as the next principal step in the dynamo process. The dependence of the strength of the magnetic field on the rotation rate is studied. Various features of the saturated magnetic field are outlined and possible saturation mechanisms are discussed.

  11. Coherent population oscillation produced by saturating probe and pump fields on the intercombination Line

    CERN Document Server

    Vafafard, A; Agarwal, G S

    2016-01-01

    We present a theoretical study of the experiments on coherent population oscillations and coher- ent population trapping on the intercombination line of 174Y b. The transition involves a change of the spin and thus can not be interpreted in terms of an effective Lambda system. The reported experiments are done in the regime where both pump and probe fields can saturate the transition. We demonstrate by both numerical and analytical calculations the appearance of the interference minimum as both pump and probe start saturating the transition. We present an analytical result for the threshold probe power when the interference minimum can appear. We also present de- tailed study of the appearance of the interference minimum when magnetic fields are applied. The magnetic fields not only create Zeeman splittings but in addition make the system open because of the couplings to other levels. We show the possibility of interference minimum at the position of subharmonic resonances.

  12. Selection of sorghum hybrids grown under aluminum saturation.

    Science.gov (United States)

    Menezes, C B; Carvalho Junior, G A; Silva, L A; Bernardino, K C; Magalhães, J V; Guimarães, C T; Guimarães, L J M; Schaffert, R E

    2014-01-01

    The purpose of this study was to evaluate 165 hybrids derived from lines previously selected for aluminum (Al) tolerance. Nine check cultivars were used, eight commercial hybrids and one experimental hybrid. Hybrids were evaluated at three levels of Al saturation (0, 20 and 40% on average). The differences between the environments were significant. Environment with 0% Al saturation yielded 29.5% more than that with 40% Al saturation, showing the importance of genotype selection for acid soils. The best check cultivar was the hybrid DKB550. The hybrids AG1020 and AG1040 also performed well, where the latter was more tolerant but the former more responsive to environment improvement. The hybrid BRS304 was susceptible to high levels of Al saturation. The three commercial BRS hybrids (BRS310, BRS330 and BRS332) performed better than BRS304 at high Al saturation. The hybrid BRS330 was the best BRS hybrid to grow on a field with high Al saturation. The hybrid DKB559 performed well at high Al saturation but did not respond to environment improvement. The hybrids 727029, 727039, 729041, 729095, 729109, AG1040, and DKB550 were tolerant to higher levels of Al saturation and responsive to environment improvement, and showed good stability and adaptability at both low and high Al saturation. PMID:25117355

  13. Estimating seismic velocities at ultrasonic frequencies in partially saturated rocks

    Energy Technology Data Exchange (ETDEWEB)

    Mavko, G.; Nolen-Hoeksema, R. (Stanford Univ., CA (United States). Dept. of Geophysics)

    1994-02-01

    Seismic velocities in rocks at ultrasonic frequencies depend not only on the degree of saturation but also on the distribution of the fluid phase at various scales within the pore space. Two scales of saturation heterogeneity are important: (1) saturation differences between thin compliant pores and larger stiffer pores, and (2) differences between saturated patches and undersaturated patches at a scale much larger than any pore. The authors propose a formalism for predicting the range of velocities in partially saturated rocks that avoids assuming idealized pore shapes by using measured dry rock velocity versus pressure and dry rock porosity versus pressure. The pressure dependence contains all of the necessary information about the distribution of pore compliance for estimating effects of saturation at the finest scales where small amounts of fluid in the thinnest, most compliant parts of the pore space stiffen the rock in both compression and shear (increasing both P- and S-wave velocities) in approximately the same way that confining pressure stiffens the rock by closing the compliant pores. Large-scale saturation patches tend to increase only the high-frequency bulk modulus by amounts roughly proportional to the saturation. The pore-scale effects will be most important at laboratory and logging frequencies when pore-scale pore pressure gradients are unrelaxed. The patchy-saturation effects can persist even at seismic field frequencies if the patch sizes are sufficiently large and the diffusivities are sufficiently low for the larger-scale pressure gradients to be unrelaxed.

  14. The role of meson dynamics in nuclear matter saturation

    International Nuclear Information System (INIS)

    The problem of the saturation of nuclea matter in the non-relativistic limit of the model proposed by J.D. Walecka is studied. In the original context nuclear matter saturation is obtained as a direct consequence of relativistic effects and both scalar and vector mesons are treated statically. In the present work we investigate the effect of the meson dynamics for the saturation using a Born-Oppenheimer approximation for the ground state. An upper limit for the saturation curve of nuclear matter and are able to decide now essential is the relativistic treatment of the nucleons for this problem, is obtained. (author)

  15. Heat Saturation Time of Solid Spherical Regenerator of HTAC

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In order to control the heat saturation time, the temperature field of the regenerators of high temperature air combustion (HTAC) technology after reheating furnace was studied. A one-dimensional unsteady mathematical model was established and discretized through finite difference method. The relationship between the heat saturation time and some factors was determined through the calculation of a program developed by language C. The heat saturation time decreases with the increase of heat convection coefficient, however, the increase of heat capacity,density and radius of regenerator all increase the heat saturation time approximately linearly.

  16. Biodegradation Rates of Aromatic Contaminants in Biofilm Reactors

    DEFF Research Database (Denmark)

    Arcangeli, Jean-Pierre; Arvin, Erik

    1995-01-01

    , chlorophenols, nitrophenol, chlorobenzenes and aromatic nitrogen-, sulphur- or oxygen-containing heterocyclic compounds (NSO-compounds). Furthermore, a comparison with degradation rates observed for easily degradable organics is also presented. At concentrations below 20-100 μg/l the degradation of the aromatic...

  17. Products Distribution of Meta-Oriented Aromatic Polyamide Needs Improvement

    Institute of Scientific and Technical Information of China (English)

    Sun Maojian

    2007-01-01

    @@ Capacity holding the second place in the world Metaoriented aromatic polya-mide fiber was first developed by DuPont of the United States. Commercial production began in the late 1960s.Today the world's capacity to produce meta-oriented aromatic polyamide fiber is 28 150t/a, and DuPont holds a 78% market share.

  18. High atmosphere-ocean exchange of semivolatile aromatic hydrocarbons

    Science.gov (United States)

    González-Gaya, Belén; Fernández-Pinos, María-Carmen; Morales, Laura; Méjanelle, Laurence; Abad, Esteban; Piña, Benjamin; Duarte, Carlos M.; Jiménez, Begoña; Dachs, Jordi

    2016-06-01

    Polycyclic aromatic hydrocarbons, and other semivolatile aromatic-like compounds, are an important and ubiquitous fraction of organic matter in the environment. The occurrence of semivolatile aromatic hydrocarbons is due to anthropogenic sources such as incomplete combustion of fossil fuels or oil spills, and other biogenic sources. However, their global transport, fate and relevance for the carbon cycle have been poorly assessed, especially in terms of fluxes. Here we report a global assessment of the occurrence and atmosphere-ocean fluxes of 64 polycyclic aromatic hydrocarbons analysed in paired atmospheric and seawater samples from the tropical and subtropical Atlantic, Pacific and Indian oceans. The global atmospheric input of polycyclic aromatic hydrocarbons to the global ocean is estimated at 0.09 Tg per month, four times greater than the input from the Deepwater Horizon spill. Moreover, the environmental concentrations of total semivolatile aromatic-like compounds were 102-103 times higher than those of the targeted polycyclic aromatic hydrocarbons, with a relevant contribution of an aromatic unresolved complex mixture. These concentrations drive a large global deposition of carbon, estimated at 400 Tg C yr-1, around 15% of the oceanic CO2 uptake.

  19. Laboratory Investigation of Organic Aerosol Formation from Aromatic Hydrocarbons

    Science.gov (United States)

    Molina, Luisa T.; Molina, Mario J.; Zhang, Renyi

    2006-08-23

    Our work for this DOE funded project includes: (1) measurements of the kinetics and mechanism of the gas-phase oxidation reactions of the aromatic hydrocarbons initiated by OH; (2) measurements of aerosol formation from the aromatic hydrocarbons; and (3) theoretical studies to elucidate the OH-toluene reaction mechanism using quantum-chemical and rate theories.

  20. Bis-perfluoroalkylation of aromatic compounds with sodium perfluoroalkanesulfinates

    Institute of Scientific and Technical Information of China (English)

    LIU, Jin-Tao(刘金涛); LU, He-Jun(吕贺军)

    2000-01-01

    Bis-perfluoroalkylation of aromatic compounds such as dimethoxybenzenes (2,4,6), anisole (8), pyridine (10) and quinoline (13) was accomplished by reaction with excess sodium perfluoroalkanesulfinates, RFSO2Na (1), in the presence of Mn(OAc)3·2H2O under mild conditions. The reaction provides a facile method for the synthesis of bis-perfluoroalkylated aromatic compounds.

  1. 40 CFR 721.757 - Polyoxyalkylene substituted aromatic azo colorant.

    Science.gov (United States)

    2010-07-01

    ... azo colorant. 721.757 Section 721.757 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.757 Polyoxyalkylene substituted aromatic azo colorant. (a) Chemical... as polyoxyalkylene substituted aromatic azo colorant (PMN P-92-1131) is subject to reporting...

  2. Electron-Exchange Reactions of Aromatic Molecules

    International Nuclear Information System (INIS)

    A large body of information is available on the rates and mechanisms of inorganic electron-exchange processes. In contrast, purely organic systems have received only minor attention. The homogeneous electron-exchange rates (kexc) and the heterogeneous rate constants for the electrode reaction (kel) have been measured only for a few hydrocarbons. We have measured kexc for a variety of aromatic systems including hydrocarbons, quinones and nitro compounds. These measurements have been carried out via electron paramagnetic resonance (EPR) line broadening measurements on mixtures of radical ions and their parent compounds. We have been able to measure kexc with a precision that allows detection of small differences presumably due to molecular structure and environment. Hydrocarbon systems like anthracene/anthracene anion are very rapid with kexc values of ca. 108-109 litres mole-1 sec-1. Some substituted aromatics like quinones and nitriles are also quite rapid. However, when a strong electron acceptor function is present like a nitro group in nitrobenzene, the value of kexc decreases by a factor of 10. It is possible to correlate changes in kexc in the nitrobenzene series with the unpaired electron density in terms of the 14N coupling constants of the EPR spectra. Further, the nitro aromatic series show very large variations in kexc with the solvent system. These changes can be correlated with recent studies of the solvation effect on hyperfine coupling constants. Marcus has reviewed recently chemical and electrochemical electron-transfer theory and suggested correlations between kexc and kel. We have measured kel especially for the nitrobenzene system under conditions which are as nearly identical experimentally to the EPR studies as possible. The electrochemical investigations were carried out by a steady-state d.c. method to eliminate some of the uncertainties inherent in electrochemical relaxation techniques. Rotated disc electrodes at low temperatures were used

  3. Pro-aromatic and anti-aromatic π-conjugated molecules: an irresistible wish to be diradicals

    KAUST Repository

    Zeng, Zebing

    2015-01-01

    © 2015 The Royal Society of Chemistry. Aromaticity is an important concept to understand the stability and physical properties of π-conjugated molecules. Recent studies on pro-aromatic and anti-aromatic molecules revealed their irresistible tendency to become diradicals in the ground state. Diradical character thus becomes another very important concept and it is fundamentally correlated to the physical (optical, electronic and magnetic) properties and chemical reactivity of most of the organic optoelectronic materials. Molecules with distinctive diradical character show unique properties which are very different from those of traditional closed-shell π-conjugated systems, and thus they have many potential applications in organic electronics, spintronics, non-linear optics and energy storage. This critical review first introduces the fundamental electronic structure of Kekulé diradicals within the concepts of anti-aromaticity and pro-aromaticity in the context of Hückel aromaticity and diradical character. Then recent research studies on various stable/persistent diradicaloids based on pro-aromatic and anti-aromatic compounds are summarized and discussed with regard to their synthetic chemistry, physical properties, structure-property relationships and potential material applications. A summary and personal perspective is given at the end.

  4. Neutron Scattering of Aromatic and Aliphatic Liquids

    Science.gov (United States)

    Falkowska, Marta; Bowron, Daniel T.; Manyar, Haresh G.

    2016-01-01

    Abstract Organic solvents, such as cyclohexane, cyclohexene, methylcyclohexane, benzene and toluene, are widely used as both reagents and solvents in industrial processes. Despite the ubiquity of these liquids, the local structures that govern the chemical properties have not been studied extensively. Herein, we report neutron diffraction measurements on liquid cyclohexane, cyclohexene, methylcyclohexane, benzene and toluene at 298 K to obtain a detailed description of the local structure in these compounds. The radial distribution functions of the centres of the molecules, as well as the partial distribution functions for the double bond for cyclohexene and methyl group for methylcyclohexane and toluene have been calculated. Additionally, probability density functions and angular radial distribution functions were extracted to provide a full description of the local structure within the chosen liquids. Structural motifs are discussed and compared for all liquids, referring specifically to the functional group and aromaticity present in the different liquids. PMID:26990367

  5. Photochemically induced oscillations of aromatic pentazadienes

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, T.; Hahn, C.; Wokaun, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Aromatic pentazadienes are used to enhance the laser induced ablation of standard polymers with low absorption in the UV. Therefore the photochemistry of substituted 1,5-diaryl-3-alkyl-1,4-pentazadiene monomers was studied with a pulsed excimer laser as irradiation source. The net photochemical reaction proceeds in an overall one-step pathway A{yields}B. Quantum yields for the laser decomposition were determined to be up to 10%. An oscillating behaviour of the absorption was found during the dark period following the irradiation. The temperature dependence of this dark reaction has been studied. An attempt to model this behaviour in terms of a non-linear coupling between heat released, heat transfer, and reaction kinetics will be described. (author) 4 figs., 4 refs.

  6. Neutron Scattering of Aromatic and Aliphatic Liquids.

    Science.gov (United States)

    Falkowska, Marta; Bowron, Daniel T; Manyar, Haresh G; Hardacre, Christopher; Youngs, Tristan G A

    2016-07-01

    Organic solvents, such as cyclohexane, cyclohexene, methylcyclohexane, benzene and toluene, are widely used as both reagents and solvents in industrial processes. Despite the ubiquity of these liquids, the local structures that govern the chemical properties have not been studied extensively. Herein, we report neutron diffraction measurements on liquid cyclohexane, cyclohexene, methylcyclohexane, benzene and toluene at 298 K to obtain a detailed description of the local structure in these compounds. The radial distribution functions of the centres of the molecules, as well as the partial distribution functions for the double bond for cyclohexene and methyl group for methylcyclohexane and toluene have been calculated. Additionally, probability density functions and angular radial distribution functions were extracted to provide a full description of the local structure within the chosen liquids. Structural motifs are discussed and compared for all liquids, referring specifically to the functional group and aromaticity present in the different liquids. PMID:26990367

  7. Muonium addition reactions to aromatic solutes

    International Nuclear Information System (INIS)

    Reaction rate constants of 0.3 to 1.1 x 10sup(10) Msup(-1) ssup(-1) were determined for the reaction of muonium (μsup(+)esup(-),Mu) with seven aromatic solutes in dilute aqueous solution at approximately 295K. The reaction was deduced to be that of addition to the benzene ring to form cyclohexadienyl radicals. On comparison with the analogous H-atom reactions, the kinetic isotope effects were generally about three, equal to the mean thermal velocity ratio of Mu/H. When analyzed through the Hammett equation there were serious discontinuities but a rho value of +0.6 was deduced, not inconsistent with attack by a mildly electron-donating neutral atom forming only free radical intermediates

  8. Naturally occurring antifungal aromatic esters and amides

    International Nuclear Information System (INIS)

    During the search of antifungal natural products from terrestrial plants, a new long chained aromatic ester named grandiflorate along with spatazoate from Portulaca grandiflora and N-[2-methoxy-2-(4-methoxyphenyl) ethyl]-trans-cinnamide and aegeline from Solanum erianthum of Nigeria were isolated and tested against six fungal species. The known constituents have not been reported so far from mentioned investigated plants. Structures of the isolated compounds were elucidated with the aid of spectroscopic techniques including two dimensional NMR experiments. Among the compounds, the esters found more potent than amides against Candida albicans and Aspergillus flavus. The new compound grandiflorate gave response against all tested fungal species while aegeline was found to give lowest inhibition during this study. (author)

  9. ANTIEMETIC ACTIVITY OF SOME AROMATIC PLANTS

    Directory of Open Access Journals (Sweden)

    Hasan MuhammadMohtasheemul

    2012-02-01

    Full Text Available Current study was conducted to explore the antiemetic activity of ten aromatic medicinal plants viz., Carissa carandus L. (fruits, Chichorium intybus L (flowers, Cinnamum tamala L (leaves, Curcuma caesia Roxb (rhizomes, Lallemantia royleana Benth (leaves, Matricaria chamomila L (flowers, Piper longum L (fruits, Piper methysticum G. Forst (fruits, Piper nigrum Linn. (fruits and Syzygium aromaticum (Linn. Merr. & Perry (flowering buds was studied using chick emetic model. The ethanol extracts of these plants were administered at 150 mg/kg body weight orally. Domperidone was given at 100 mg/kg as a reference drug. All the extracts decrease in retches induced by copper sulphate pentahydrate given orally at 50 mg/kg body weight and showed comparable antiemetic activity with domperidone. Compound targeted antiemetic activity is further suggested.

  10. Eco-physiological Effects of Atmospheric Ozone and Polycyclic Aromatic Hydrocarbons (PAHs) on Plants

    Science.gov (United States)

    Bandai, S.; Sakugawa, H. H.

    2012-12-01

    [Introduction] Tropospheric ozone is one of most concerned air pollutant, by causing damage to trees and crops. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants found in various environmental compartments. Photo-induced toxicity of PAHs can be driven from formation of intracellular single oxygen and other reactive oxygen intermediates (ROI) leading to biological damages.(1) In the present study, we measured photosynthesis rate and other variables to investigate the effects of ozone and PAHs on the eco-physiological status of plants such as eggplant, common bean and strawberry. Plants treated with the single or combined air pollutants are expected to exhibit altered physiological, morphological and possibly growth changes. [Materials and Methods] We performed three exposure experiments. Exp.1. Eggplant (Solanum melongena) seedlings, were placed in the open-top chambers (n=6 plants/treatment). Treatment system was ozone (O)(120ppb), phenanthrene (P)(10μM), O+P, fluoranthene (F)(10μM), O+F, mannitol (M)(1mM) and the control (Milli-Q water)(C). P, F and M were sprayed three times weekly on the foliage part of eggplant. Average volume sprayed per seedling was 50mL. The treatment period was 30days and [AOT 40 (Accumulated exposure over a threshold of 40 ppb)]=28.8 ppmh. Exp.2, Common bean (Phaseolus vulgaris L.) seedlings were used (n=5 plants/treatment). The treatment system was the same as Exp.1. The treatment period was 40days and [AOT 40]=38.4ppmh. Exp.3. Strawberry (Fragaria L.) seedlings were used (n=5 plants/treatment). Treatment system was O (120ppb), F(10μM), O+F, F+M, O+M and C. The treatment period was 90days and [AOT 40]=86.4ppmh. Ecophysiological variables examined were photosynthesis rate measured at saturated irradiance (Amax), stomatal conductance to water vapour (gs), internal CO2 concentration (Ci), photochemical efficiency of PS2 in the dark (Fv/Fm), chlorophyll contents, visual symptom assessment and elemental composition in the

  11. Aromatic fluorine compounds. VII. Replacement of aromatic -Cl and -NO2 groups by -F

    Science.gov (United States)

    Finger, G.C.; Kruse, C.W.

    1956-01-01

    Replacement of -Cl by -F in aryl chlorides with potassium fluoride has been extended from 2,4-dinitrochlorobenzene to less activated halides by the use of non-aqueous solvents, especially dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). Also replacement of -NO2 by -F in substituted nitrobenzenes was studied in DMF. As a direct result of this study, many aromatic fluorine compounds can now be obtained by a relatively simple synthetic route.

  12. Environmental Remediation: Removal of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Nkansah, Marian Asantewah

    2012-11-15

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous persistent semi-volatile organic compounds. They are contaminants that are resistant to degradation and can remain in the environment for long periods due to their high degree of conjugation, and aromaticity. PAHs are present in industrial effluents as products of incomplete combustion processes of organic compounds. Petroleum, coal and shale oil contain extremely complex mixtures of these PAHs, and their transport and refining process can also result in the release of PAHs. It is therefore prudent that such effluents are treated before discharge into the environment. In this project, different approaches to the treatment of PAHs have been investigated. Hydrous pyrolysis has been explored as a potential technique for degrading PAHs in water using anthracene as a model compound. The experiments were performed under different conditions of temperature, substrate, redox systems and durations. The conditions include oxidising systems comprising pure water, hydrogen peroxide and Nafion-SiO2 solid catalyst in water; and reducing systems of formic acid and formic acid / Nafion-SiO2 / Pd-C catalysts to assess a range of reactivities. Products observed in GCMS analysis of the extract from the water phase include anthrone, anthraquinone, xanthone and multiple hydro-anthracene derivatives (Paper I). In addition a modified version of the Nafion-SiO2 solid catalyst in water oxidising system was tested; and reducing systems of formic acid and formic acid / Nafion-SiO2 / Pd-C catalysts were adopted for the conversion of a mixture of anthracene, fluorene and fluoranthene. The rate of conversion in the mixture was high as compared to that of only anthracene (Paper II). Also the use of LECA (Lightweight expanded clay aggregates) as an adsorbent (Paper III) for PAHs (phenanthrene, fluoranthene and pyrene) removal from water has been.(Author)

  13. Characterizing polycyclic aromatic hydrocarbon build-up processes on urban road surfaces.

    Science.gov (United States)

    Liu, Liang; Liu, An; Li, Dunzhu; Zhang, Lixun; Guan, Yuntao

    2016-07-01

    Reliable prediction models are essential for modeling pollutant build-up processes on urban road surfaces. Based on successive samplings of road deposited sediments (RDS), this study presents empirical models for mathematical replication of the polycyclic aromatic hydrocarbon (PAH) build-up processes on urban road surfaces. The contaminant build-up behavior was modeled using saturation functions, which are commonly applied in US EPA's Stormwater Management Model (SWMM). Accurate fitting results were achieved in three typical urban land use types, and the applicability of the models was confirmed based on their acceptable relative prediction errors. The fitting results showed high variability in PAH saturation value and build-up rate among different land use types. Results of multivariate data and temporal-based analyses suggested that the quantity and property of RDS significantly influenced PAH build-up. Furthermore, pollution sources, traffic parameters, road surface conditions, and sweeping frequency could synthetically impact the RDS build-up and RDS property change processes. Thus, changes in these parameters could be the main reason for variations in PAH build-up in different urban land use types. PMID:27086074

  14. Gain characteristics of a saturated fiber optic parametric amplifier

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Lorenzen, Michael Rodas; Noordegraaf, Danny;

    2008-01-01

    In this work we discuss saturation performance of a fiber optic parametric amplifier. A simple numerical model is described and applied to specific cases. A system experiment using a saturated amplifier illustrates a 4 dB improvement in required signal to noise ratio for a fixed bit error ratio....

  15. Excitable solitons in a semiconductor laser with a saturable absorber

    Science.gov (United States)

    Turconi, Margherita; Prati, Franco; Barland, Stéphane; Tissoni, Giovanna

    2015-11-01

    Self-pulsing cavity solitons may exist in a semiconductor laser with an intracavity saturable absorber. They show locally the passive Q -switching behavior that is typical of lasers with saturable absorbers in the plane-wave approximation. Here we show that excitable cavity solitons are also possible in a suitable parameter range and characterize their excitable dynamics and properties.

  16. Stability and stabilization of linear systems with saturating actuators

    CERN Document Server

    Tarbouriech, Sophie; Gomes da Silva Jr, João Manoel; Queinnec, Isabelle

    2011-01-01

    Gives the reader an in-depth understanding of the phenomena caused by the more-or-less ubiquitous problem of actuator saturation. Proposes methods and algorithms designed to avoid, manage or overcome the effects of actuator saturation. Uses a state-space approach to ensure local and global stability of the systems considered. Compilation of fifteen years' worth of research results.

  17. Nonmonotone Saturation Profiles for Hydrostatic Equilibrium in Homogeneous Porous Media

    NARCIS (Netherlands)

    Hilfer, R.; Doster, F.; Zegeling, P.A.

    2012-01-01

    Nonmonotonic saturation profiles (saturation overshoot) occur as travelling waves in gravity driven fingering. They seem important for preferential flow mechanisms and have found much attention recently. Here, we predict them even for hydrostatic equilibrium when all velocities vanish. We suggest th

  18. Quantitative 1D saturation profiles on chalk by NMR

    DEFF Research Database (Denmark)

    Olsen, Dan; Topp, Simon; Stensgaard, Anders;

    1996-01-01

    Quantitative one-dimensional saturation profiles showing the distribution of water and oil in chalk core samples are calculated from NMR measurements utilizing a 1D CSI spectroscopy pulse sequence. Saturation profiles may be acquired under conditions of fluid flow through the sample. Results reveal...

  19. Determination of residual oil saturation from time-lapse pulsed neutron capture logs in a large sandstone reservoir

    International Nuclear Information System (INIS)

    Cased hole logging with pulsed neutron tools finds extensive use for identifying zones of water breakthrough and monitoring oil-water contacts in oil reservoirs being depleted by waterflooding or natural water drive. Results of such surveys then find direct use for planning recompletions and water shutoff treatments. Pulsed neutron capture (PNC) logs are useful for estimating water saturation changes behind casing in the presence of a constant, high-salinity environment. PNC log surveys run at different times, i.e., in a time-lapse mode, are particularly amenable to quantitative analysis. The combined use of the original open hole and PNC time-lapse log information can then provide information on remaining or residual oil saturations in a reservoir. This paper reports analyses of historical pulsed neutron capture log data to assess residual oil saturation in naturally water-swept zones for selected wells from a large sandstone reservoir in the Middle East

  20. Numerical method for computing flow through partially saturated porous media

    Science.gov (United States)

    Eaton, R. R.

    This paper discusses the development of the finite element computer code SAGUARO which calculates the two-dimensional flow of mass and energy through porous media. The media may be saturated or partially saturated. SAGUARO solves the parabolic time-dependent mass transport equation which accounts for the presence of partially saturated zones through the use of highly non-linear material characteristic curves. The energy equation accounts for the possibility of partially-saturated regions by adjusting the thermal capacitances and thermal conductivities according to the volume fraction of water present in the local pores. The code capabilities are demonstrated through the presentation of a sample problem involving the one dimensional calculation of simultaneous energy transfer and water infiltration into partially saturated hard rock.

  1. Input saturation in nonlinear multivariable processes resolved by nonlinear decoupling

    Directory of Open Access Journals (Sweden)

    Jens G. Balchen

    1995-04-01

    Full Text Available A new method is presented for the resolution of the problem of input saturation in nonlinear multivariable process control by means of elementary nonlinear decoupling (END. Input saturation can have serious consequences particularly in multivariable control because it may lead to very undesirable system behaviour and quite often system instability. Many authors have searched for systematic techniques for designing multivariable control systems in which saturation may occur in any of the control variables (inputs, manipulated variables. No generally accepted method seems to have been presented so far which gives a solution in closed form. The method of elementary nonlinear decoupling (END can be applied directly to the case of saturation control variables by deriving as many control strategies as there are combinations of saturating control variables. The method is demonstrated by the multivariable control of a simulated Fluidized Catalytic Cracker (FCC with very convincing results.

  2. Saturation mechanism in clarinet-like instruments, the effect of the localised non-linear losses

    OpenAIRE

    Atig, Merouane; Dalmont, Jean-Pierre; Gilbert, Joël

    2004-01-01

    The question of what limits the amplitude of the oscillations of clarinet-like instruments is investigated. The study is based on numerical simulations in which two kind of losses are taken into account: linear losses and non-linear losses localised at the open end of the tube. The influence of the amount of losses on the saturation process and on the playing range of clarinet-like instruments is shown. Results are confirmed by experiments using an artificial mouth in which the non-linear los...

  3. The future role of aromatics in refining and petrochemistry. Proceedings of the DGMK-Conference (Authors' manuscripts)

    Energy Technology Data Exchange (ETDEWEB)

    Emig, G.; Rupp, M.; Weitkamp, J. [eds.

    1999-07-01

    Topic of this conference has been the furure role of aromatics in the refinign industry. The articles deal with the following topics: Refining; legal aspects in the aromatics market; transportation fuels; dearomatization; catalytic reforming and aromatics; separation processes for aromatics; oxidation and ammoxidation of aromatics; electrophilic substitution of aromatics; hydrogenation of benzene; zeolites. (orig./sr)

  4. Streaming Potential In Rocks Saturated With Water And Oil

    Science.gov (United States)

    Tarvin, J. A.; Caston, A.

    2011-12-01

    Fluids flowing through porous media generate electrical currents. These currents cause electric potentials, called "streaming potentials." Streaming potential amplitude depends on the applied pressure gradient, on rock and fluid properties, and on the interaction between rock and fluid. Streaming potential has been measured for rocks saturated with water (1) and with water-gas mixtures. (2) Few measurements (3) have been reported for rocks saturated with water-oil mixtures. We measured streaming potential for sandstone and limestone saturated with a mixture of brine and laboratory oil. Cylindrical samples were initially saturated with brine and submerged in oil. Saturation was changed by pumping oil from one end of a sample to the other and then through the sample in the opposite direction. Saturation was estimated from sample resistivity. The final saturation of each sample was determined by heating the sample in a closed container and measuring the pressure. Measurements were made by modulating the pressure difference (of oil) between the ends of a sample at multiple frequencies below 20 Hz. The observed streaming potential is a weak function of the saturation. Since sample conductivity decreases with increasing oil saturation, the electro-kinetic coupling coefficient (Pride's L (4)) decreases with increasing oil saturation. (1) David B. Pengra and Po-zen Wong, Colloids and Surfaces, vol., p. 159 283-292 (1999). (2) Eve S. Sprunt, Tony B. Mercer, and Nizar F. Djabbarah, Geophysics, vol. 59, p. 707-711 (1994). (3) Vinogradov, J., Jackson, M.D., Geophysical Res. L., Vol. 38, Article L01301 (2011). (4) Steve Pride, Phys. Rev. B, vol. 50, pp. 15678-15696 (1994).

  5. Understanding NMR relaxometry of partially water-saturated rocks

    Directory of Open Access Journals (Sweden)

    O. Mohnke

    2014-11-01

    Full Text Available Nuclear Magnetic Resonance (NMR relaxometry measurements are commonly used to characterize the storage and transport properties of water-saturated rocks. These assessments are based on the proportionality of NMR signal amplitude and relaxation time to porosity (water content and pore size, respectively. The relationship between pore size and NMR relaxation time depends on pore shape, which is usually assumed to be spherical or cylindrical. However, the NMR response at partial water saturation for natural sediments and rocks differs strongly from the response calculated for spherical or cylindrical pores, because these pore shapes cannot account for water menisci remaining in the corners of de-saturated angular pores. Therefore, we consider a bundle of pores with triangular cross-sections. We introduce analytical solutions of the NMR equations at partial saturation of these pores, which account for water menisci of de-saturated pores. After developing equations that describe the water distribution inside the pores, we calculate the NMR response at partial saturation for imbibition and drainage based on the deduced water distributions. For this pore model, NMR amplitude and NMR relaxation time at partial water saturation strongly depend on pore shape even so the NMR relaxation time at full saturation only depends on the surface to volume ratio of the pore. The pore-shape-dependence at partial saturation arises from the pore shape and capillary pressure dependent water distribution in pores with triangular cross-sections. Moreover, we show the qualitative agreement of the saturation dependent relaxation time distributions of our model with those observed for rocks and soils.

  6. Aromatic hydrocarbon concentrations in sediments of Placentia Bay, Newfoundland

    International Nuclear Information System (INIS)

    A study was conducted to examine the potential for contamination of recent sediments with polycyclic aromatic hydrocarbons due to tanker and refinery activity in Placentia Bay, Newfoundland, an area without large local anthropogenic sources of aromatics. Sediment samples were taken from the vicinity of the Come By Chance refinery, Woody Island, Wild Cove, and Port Royal Arm, all in the north end of the bay. The samples were extracted by two methods, dichloromethane extraction of dried sediment for determination of total aromatic hydrocarbon content and hexane extraction of wet sediment for estimation of the bioavailability of hydrocarbons and determination of more volatile compounds. Class analysis of aromatic hydrocarbons was conducted on a NH2 column with detection at 255 nm. Total concentrations of di-tricyclic aromatics were highest at the Woody Island site (0.6 μg/g). The sediments from the Come By Chance site, Wild Cove, and Port Royal Arm sediments contained 0.3, 0.1, and 0.2 μg/g respectively. The hexane extracts from Come By Chance were lowest in di-tricyclic aromatics (0.007 μg/g), with the other sites being equal in concentration (0.01 μg/g). It is evident from the study that aromatic hydrocarbon concentrations in Placentia Bay are elevated in some parts of the bay in the absence of local combustion sources, and that the most likely source is petroleum. 12 refs., 5 figs., 2 tabs

  7. How non-conventional feedstocks will affect aromatics technologies

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, E. [Clariant Produkte (Deutschland) GmbH, Muenchen (Germany)

    2013-11-01

    The abundance of non-conventional feedstocks such as coal and shale gas has begun to affect the availability of traditional base chemicals such as propylene and BTX aromatics. Although this trend is primarily fueled by the fast growing shale gas economy in the US and the abundance of coal in China, it will cause the global supply and demand situation to equilibrate across the regions. Lower demand for gasoline and consequently less aromatics rich reformate from refineries will further tighten the aromatics markets that are expected to grow at healthy rates, however. Refiners can benefit from this trend by abandoning their traditional fuel-oriented business model and becoming producers of petrochemical intermediates, with special focus on paraxylene (PX). Cheap gas from coal (via gasification) or shale reserves is an advantaged feedstock that offers a great platform to make aromatics in a cost-competitive manner, especially in regions where naphtha is in short supply. Gas condensates (LPG and naphtha) are good feedstocks for paraffin aromatization, and methanol from coal or (shale) gas can be directly converted to BTX aromatics (MTA) or alkylated with benzene or toluene to make paraxylene. Most of today's technologies for the production and upgrading of BTX aromatics and their derivatives make use of the unique properties of zeolites. (orig.)

  8. Permeability of compacted saturated clays from high stress consolidation test

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In the past years, compacted bentonites have been proposed as suitable barrier and backfilling materials in the toxic waste repositories. In the waste disposal repositories at depths ranging from 500 m to 1000 m, the saturated host rock serves as the source for supplying fluid to the compacted bentonites and also acts as confinement against the volume increase. Considering the stress level at the location of the waste disposal repositories and the stress convergence of the host rock with the compacted saturated bentonites, it is necessary to study the permeability of compacted saturated bentonites for these conditions. The behaviour of compacted expansive clays has been intensively studied since last three decades with respect to key aspects such as swelling pressure, swell potential, compressibility, water absorption and desorption, temperature dependent behaviour of the material, micro-structural features. In contrast, less information about fluid flow in compacted bentonites is available in literature. In the present study, the permeability was determined indirectly based on consolidation tests of compacted saturated clay specimens. The material used was Calcigel bentonite and Spergau kaolin in order to investigate the effect of different mineralogy. De-ionised water was used as the fluid. The initial dry densities?d (in Mg/m3) and water contents w (in %) of the compacted bentonite specimens (CB1 to CB9) and those of the compacted Spergau kaolin specimens (CK1 to CK6) are presented. The initially compacted clay specimens were allowed to saturate at constant volume condition (phase 1) and were then submitted to vertical stresses higher than the swelling pressure measured (phase 2). Maximum applied vertical stress was 25 MPa. The special high stress odometer device used is described in detail in Baille et al. (2010). For each loading step, the coefficient of consolidation, cv was determined from the time

  9. Theoretical study of aromaticity in inorganic tetramer clusters

    Indian Academy of Sciences (India)

    Sandeep Nigam; Chiranjib Majumder; S K Kulshreshtha

    2006-11-01

    Ground state geometry and electronic structure of M$^{2-}_{4}$ cluster (M = B, Al, Ga) have been investigated to evaluate their aromatic properties. The calculations are performed by employing the Density Functional Theory (DFT) method. It is found that all these three clusters adopt square planar configuration. Results reveal that square planar M$^{2-}_{4}$ dianion exhibits characteristics of multifold aromaticity with two delocalised -electrons. In spite of the unstable nature of these dianionic clusters in the gas phase, their interaction with the sodium atoms forms very stable dipyramidal M4Na2 complexes while maintaining their square planar structure and aromaticity.

  10. POLYCYCLIC AROMATIC HYDROCARBONS AND THE DIFFUSE INTERSTELLAR BANDS: A SURVEY

    International Nuclear Information System (INIS)

    We discuss the proposal of relating the origin of some of the diffuse interstellar absorption bands (DIBs) to neutral polycyclic aromatic hydrocarbons (PAHs) present in translucent interstellar clouds. An assessment of ionized PAHs will be examined in a future report. The spectra of several cold, isolated gas-phase PAHs have been measured in the laboratory under experimental conditions that mimic the interstellar conditions and are compared with an extensive set of astronomical spectra of reddened, early-type stars. This comparison provides-for the first time-accurate upper limits for the abundances of specific PAH molecules along specific lines of sight, something not attainable from IR observations alone. The comparison of these unique laboratory data with high-resolution, high signal-to-noise ratio spectra leads to two major findings: (1) a finding specific to the individual molecules that were probed in this study and, which leads to the clear and unambiguous conclusion that the abundance of these specific neutral PAHs must be very low in the individual translucent interstellar clouds that were probed in this survey (PAH features remain below the level of detection) and, (2) a general finding that neutral PAHs exhibit intrinsic band profiles that are similar to the profile of the narrow DIBs indicating that the carriers of the narrow DIBs must have close molecular structure and characteristics. This study is the first quantitative survey of neutral PAHs in the optical range and it opens the way for unambiguous quantitative searches of PAHs in a variety of interstellar and circumstellar environments.

  11. Kinetics and mechanisms of reactions involving small aromatic reactive intermediates

    Energy Technology Data Exchange (ETDEWEB)

    Lin, M.C. [Emory Univ., Atlanta, GA (United States)

    1993-12-01

    Small aromatic radicals such as C{sub 6}H{sub 5}, C{sub 6}H{sub 5}O and C{sub 6}H{sub 4} are key prototype species of their homologs. C{sub 6}H{sub 5} and its oxidation product, C{sub 6}H{sub 5}O are believed to be important intermediates which play a pivotal role in hydrocarbon combustion, particularly with regard to soot formation. Despite their fundamental importance, experimental data on the reaction mechanisms and reactivities of these species are very limited. For C{sub 6}H{sub 5}, most kinetic data except its reactions with NO and NO{sub 2}, were obtained by relative rate measurements. For C{sub 6}H{sub 5}O, the authors have earlier measured its fragmentation reaction producing C{sub 5}H{sub 5} + CO in shock waves. For C{sub 6}H{sub 4}, the only rate constant measured in the gas phase is its recombination rate at room temperature. The authors have proposed to investigate systematically the kinetics and mechanisms of this important class of molecules using two parallel laser diagnostic techniques--laser resonance absorption (LRA) and resonance enhanced multiphoton ionization mass spectrometry (REMPI/MS). In the past two years, study has been focused on the development of a new multipass adsorption technique--the {open_quotes}cavity-ring-down{close_quotes} technique for kinetic applications. The preliminary results of this study appear to be quite good and the sensitivity of the technique is at least comparable to that of the laser-induced fluorescence method.

  12. Emissions from Open burning of Used Agricultural Pesticide Containers

    Science.gov (United States)

    Emissions from simulated open burning of used agricultural pesticide containers were sampled for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs), polycyclic aromatic hydrocarbon compounds (PAHs), and particle matter (PM10 and PM2.5). Clean high density polyethyl...

  13. Microfiber-based few-layer black phosphorus saturable absorber for ultra-fast fiber laser

    CERN Document Server

    Luo, Zhi-Chao; Guo, Zhi-Nan; Jiang, Xiao-Fang; Luo, Ai-Ping; Zhao, Chu-Jun; Yu, Xue-Feng; Xu, Wen-Cheng; Zhang, Han

    2015-01-01

    Few-layer black phosphorus (BP), as the most alluring graphene analogue owing to its similar structure as graphene and thickness dependent direct band-gap, has now triggered a new wave of research on two-dimensional (2D) materials based photonics and optoelectronics. However, a major obstacle of practical applications for few-layer BPs comes from their instabilities of laser-induced optical damage. Herein, we demonstrate that, few-layer BPs, fabricated through the liquid exfoliation approach, can be developed as a new and practical saturable absorber (SA) by depositing few-layer BPs with microfiber. The saturable absorption property of few-layer BPs had been verified through an open-aperture z-scan measurement at the telecommunication band and the microfiber-based BP device had been found to show a saturable average power of ~4.5 mW and a modulation depth of 10.9%, which is further confirmed through a balanced twin detection measurement. By further integrating this optical SA device into an erbium-doped fiber...

  14. Impact of sample geometry on the measurement of pressure-saturation curves: experiments and simulations

    CERN Document Server

    Moura, M; Måløy, Knut Jørgen; Schäfer, G; Toussaint, R

    2015-01-01

    In this paper we study the influence of sample geometry on the measurement of pressure-saturation relationships, by analyzing the drainage of a two-phase flow from a quasi-2D random porous medium. The medium is transparent, which allows for the direct visualization of the invasion pattern during flow, and is initially saturated with a viscous liquid (a dyed glycerol-water mix). As the pressure in the liquid is gradually reduced, air penetrates from an open inlet, displacing the liquid which leaves the system from an outlet on the opposite side. Pressure measurements and images of the flow are recorded and the pressure-saturation relationship is computed. We show that this relationship depends on the system size and aspect ratio. The effects of the system's boundaries on this relationship are measured experimentally and compared with simulations produced using an invasion percolation algorithm. The pressure build up at the beginning and end of the invasion process are particularly affected by the boundaries of...

  15. Transport of synthetic colloids through single saturated fractures: A literature review

    International Nuclear Information System (INIS)

    Colloids having the same surface charge sign as the bulk of the geologic media in a groundwater system may be able to travel through the system faster than soluble species because they will follow fluid streamlines more closely and they should have less tendency to diffuse into pores or dead spaces in the media than soluble species. Synthetic colloids with uniform, controlled properties may be ideal for serving as open-quotes worst-caseclose quotes tracers that provide lower-bound estimates of contaminant travel times in hydrologic systems. This report discusses a review of the literature pertaining to colloid transport in single saturated natural fractures. After a brief background discussion to put the literature review in perspective, the phenomenon of colloid transport in saturated fractures is divided into three major topics, each of which is reviewed in detail: (1) saturated fluid flow through fractures; (2) colloid transport by convection, diffusion, and force fields; and (3) colloid interactions with surfaces. It is suggested that these phenomena be accounted for in colloid transport models by using (1) lubrication theory to describe water flow through fractures, (2) particle tracking methods to describe colloid transport in fractures, and (3) a kinetic boundary layer approximation to describe colloid interactions with fracture walls. These methods offer better computational efficiency and better experimental accessibility to model parameters than rigorously solving the complete governing equations

  16. Effect of calcium carbonate saturation of seawater on coral calcification

    Science.gov (United States)

    Gattuso, J.-P.; Frankignoulle, M.; Bourge, I.; Romaine, S.; Buddemeier, R.W.

    1998-01-01

    The carbonate chemistry of seawater is usually not considered to be an important factor influencing calcium-carbonate-precipitation by corals because surface seawater is supersaturated with respect to aragonite. Recent reports, however, suggest that it could play a major role in the evolution and biogeography of recent corals. We investigated the calcification rates of five colonies of the zooxanthellate coral Stylophora pistillata in synthetic seawater using the alkalinity anomaly technique. Changes in aragonite saturation from 98% to 585% were obtained by manipulating the calcium concentration. The results show a nonlinear increase in calcification rate as a function of aragonite saturation level. Calcification increases nearly 3-fold when aragonite saturation increases from 98% to 390%, i.e., close to the typical present saturation state of tropical seawater. There is no further increase of calcification at saturation values above this threshold. Preliminary data suggest that another coral species, Acropora sp., displays a similar behaviour. These experimental results suggest: (l) that the rate of calcification does not change significantly within the range of saturation levels corresponding to the last glacial-interglacial cycle, and (2) that it may decrease significantly in the future as a result of the decrease in the saturation level due to anthropogenic release of CO2 into the atmosphere. Experimental studies that control environmental conditions and seawater composition provide unique opportunities to unravel the response of corals to global environmental changes.

  17. On the propagation of a coupled saturation and pressure front

    Energy Technology Data Exchange (ETDEWEB)

    Vasco, D. W.

    2010-12-01

    Using an asymptotic technique, valid for a medium with smoothly varying heterogeneity, I derive an expression for the velocity of a propagating, coupled saturation and pressure front. Due to the nonlinearity of the governing equations, the velocity of the propagating front depends upon the magnitude of the saturation and pressure changes across the front in addition to the properties of the medium. Thus, the expression must be evaluated in conjunction with numerical reservoir simulation. The propagation of the two-phase front is governed by the background saturation distribution, the saturation-dependent component of the fluid mobility, the porosity, the permeability, the capillary pressure function, the medium compressibility, and the ratio of the slopes of the relative permeability curves. Numerical simulation of water injection into a porous layer saturated with a nonaqueous phase liquid indicates that two modes of propagation are important. The fastest mode of propagation is a pressure-dominated disturbance that travels through the saturated layer. This is followed, much later, by a coupled mode with a large saturation change. These two modes are also observed in a simulation using a heterogeneous porous layer. A comparison between the propagation times estimated from the results of the numerical simulation and predictions from the asymptotic expression indicates overall agreement.

  18. Dispersants as used in response to the MC252-spill lead to higher mobility of polycyclic aromatic hydrocarbons in oil-contaminated Gulf of Mexico sand.

    Directory of Open Access Journals (Sweden)

    Alissa Zuijdgeest

    Full Text Available After the explosion of the Deepwater Horizon oil rig, large volumes of crude oil were washed onto and embedded in the sandy beaches and sublittoral sands of the Northern Gulf of Mexico. Some of this oil was mechanically or chemically dispersed before reaching the shore. With a set of laboratory-column experiments we show that the addition of chemical dispersants (Corexit 9500A increases the mobility of polycyclic aromatic hydrocarbons (PAHs in saturated permeable sediments by up to two orders of magnitude. Distribution and concentrations of PAHs, measured in the solid phase and effluent water of the columns using GC/MS, revealed that the mobility of the PAHs depended on their hydrophobicity and was species specific also in the presence of dispersant. Deepest penetration was observed for acenaphthylene and phenanthrene. Flushing of the columns with seawater after percolation of the oiled water resulted in enhanced movement by remobilization of retained PAHs. An in-situ benthic chamber experiment demonstrated that aromatic hydrocarbons are transported into permeable sublittoral sediment, emphasizing the relevance of our laboratory column experiments in natural settings. We conclude that the addition of dispersants permits crude oil components to penetrate faster and deeper into permeable saturated sands, where anaerobic conditions may slow degradation of these compounds, thus extending the persistence of potentially harmful PAHs in the marine environment. Application of dispersants in nearshore oil spills should take into account enhanced penetration depths into saturated sands as this may entail potential threats to the groundwater.

  19. Hydrate morphology: Physical properties of sands with patchy hydrate saturation

    Science.gov (United States)

    Dai, S.; Santamarina, J.C.; Waite, William F.; Kneafsey, T.J.

    2012-01-01

    The physical properties of gas hydrate-bearing sediments depend on the volume fraction and spatial distribution of the hydrate phase. The host sediment grain size and the state of effective stress determine the hydrate morphology in sediments; this information can be used to significantly constrain estimates of the physical properties of hydrate-bearing sediments, including the coarse-grained sands subjected to high effective stress that are of interest as potential energy resources. Reported data and physical analyses suggest hydrate-bearing sands contain a heterogeneous, patchy hydrate distribution, whereby zones with 100% pore-space hydrate saturation are embedded in hydrate-free sand. Accounting for patchy rather than homogeneous hydrate distribution yields more tightly constrained estimates of physical properties in hydrate-bearing sands and captures observed physical-property dependencies on hydrate saturation. For example, numerical modeling results of sands with patchy saturation agree with experimental observation, showing a transition in stiffness starting near the series bound at low hydrate saturations but moving toward the parallel bound at high hydrate saturations. The hydrate-patch size itself impacts the physical properties of hydrate-bearing sediments; for example, at constant hydrate saturation, we find that conductivity (electrical, hydraulic and thermal) increases as the number of hydrate-saturated patches increases. This increase reflects the larger number of conductive flow paths that exist in specimens with many small hydrate-saturated patches in comparison to specimens in which a few large hydrate saturated patches can block flow over a significant cross-section of the specimen.

  20. Prediction of saturated liquid enthalpy of refrigerant mixtures

    Institute of Scientific and Technical Information of China (English)

    CHEN ZeShao; CHEN JianXin; HU Peng

    2007-01-01

    New corresponding temperature and corresponding enthalpy of refrigerant mixtures were defined. The relationship between saturated liquid corresponding enthalpy and corresponding temperature of refrigerant mixtures accorded with that of pure components. The characteristic parameters of saturated liquid enthalpy difference of refrigerant mixtures were calculated by three methods according to the different application conditions. The generalized equation of saturated liquid enthalpy of refrigerant mixtures was presented. The calculated values were compared with the values in literature for five ternary and binary refrigerant mixtures, namely R404A, R407A, R407B, R32/R134a, and R410A. The overall average absolute deviation was less than 1.0%.

  1. The Reverse Saturation Absorption Property of Indanthrone and Its Derivatives

    Institute of Scientific and Technical Information of China (English)

    LIU Dajun; DUAN Qian; HE Xingquan; ZOU Ying

    2005-01-01

    The syntheses of three nonlinear reverse saturation absorption compounds-Indanthrone and its two derivatives are discussed. The properties of nonlinear reverse saturable absorption of the compounds were studied by using the Z- scanning technique, and the influences of its conjugated structure on the absorption threshold value and the absorbable light density were discussed based on the reverse saturation absorption principle. The results shows that when the structure' s conjugation property of Indanthrone and its derivatives becomes more powerful , its absorption threshold reduces, the light lowest transmittance increases.

  2. Saturable absorption in multi-core fiber couplers

    CERN Document Server

    Nazemosadat, Elham

    2013-01-01

    The saturable absorption characteristics of two-, three-, and five-core one-dimensional fiber coupler arrays and the seven-core hexagonal fiber coupler array are investigated. It is shown that the performance of all these saturable absorbers are comparable and not much is gained, if anything, by going from a two-core nonlinear coupler geometry to a higher number of cores. This observation is supported by the similarity of the saturable absorption curves, as well as comparable pulse characteristics obtained from the simulation of a generic mode-locked fiber laser cavity.

  3. An Elastoplastic Model for Partially Saturated Collapsible Rocks

    Science.gov (United States)

    Ma, Jianjun

    2016-02-01

    A unified elastoplastic model for describing the stress-strain behavior of partially saturated collapsible rocks is proposed. The elastic-plastic response due to loading and unloading is captured using bounding surface plasticity. The coupling effect of hydraulic and mechanical responses is addressed by applying the effective stress concept. Special attention is paid to the rock-fluid characteristic curve (RFCC), effective stress parameter, and suction hardening. A wide range of saturation degree is considered. The characteristics of mechanical behavior in partially saturated collapsible rocks are captured for all cases considered.

  4. Application of aromatization catalyst in synthesis of carbon nanotubes

    Indian Academy of Sciences (India)

    Song Rongjun; Yang Yunpeng; Ji Qing; Li Bin

    2012-02-01

    In a typical chemical vapour deposition (CVD) process for synthesizing carbon nanotubes (CNTs), it was found that the aromatization catalysts could promote effectively the formation of CNT. The essence of this phenomenon was attributed to the fact that the aromatization catalyst can accelerate the dehydrogenation–cyclization and condensation reaction of carbon source, which belongs to a necessary step in the formation of CNTs. In this work, aromatization catalysts, H-beta zeolite, HZSM-5 zeolite and organically modified montmorillonite (OMMT) were chosen to investigate their effects on the formation of multi-walled carbon nanotubes (MWCNTs) via pyrolysis method when polypropylene and 1-hexene as carbon source and Ni2O3 as the charring catalyst. The results demonstrated that the combination of those aromatization catalysts with nickel catalyst can effectively improve the formation of MWCNTs.

  5. Affinity labelling enzymes with esters of aromatic sulfonic acids

    Science.gov (United States)

    Wong, Show-Chu; Shaw, Elliott

    1977-01-01

    Novel esters of aromatic sulfonic acids are disclosed. The specific esters are nitrophenyl p- and m-amidinophenylmethanesulfonate. Also disclosed is a method for specific inactivation of the enzyme, thrombin, employing nitrophenyl p-amidinophenylmethanesulfonate.

  6. Six-Membered Aromatic Polyazides: Synthesis and Application

    Directory of Open Access Journals (Sweden)

    Sergei V. Chapyshev

    2015-10-01

    Full Text Available Aromatic polyazides are widely used as starting materials in organic synthesis and photochemical studies, as well as photoresists in microelectronics and as cross-linking agents in polymer chemistry. Some aromatic polyazides possess high antitumor activity, while many others are of considerable interest as high-energy materials and precursors of high-spin nitrenes and C3N4 carbon nitride nanomaterials. The use of aromatic polyazides in click-reactions may be a new promising direction in the design of various supramolecular systems possessing interesting chemical, physical and biological properties. This review is devoted to the synthesis, properties and applications of six-membered aromatic compounds containing three and more azido groups in the ring.

  7. THE UPTAKE OF AROMATIC AND BRANCHED CHAIN HYDROCARBONS BY YEAST

    Science.gov (United States)

    Studies of the hydrocarbon utilizing yeasts, Candida maltosa and C. lipolytica, have shown that both were capable of reducing recoverable amounts of branched chain and aromatic hydrocarbons in a mixture of naphthalene, tetradecane, hexadecane, pristane (tetra-methylpentadecane). ...

  8. Aromatic Plants as a Source of Bioactive Compounds

    Directory of Open Access Journals (Sweden)

    Panagiota Florou-Paneri

    2012-09-01

    Full Text Available Aromatic plants, also known as herbs and spices, have been used since antiquity as folk medicine and as preservatives in foods. The best known aromatic plants, such as oregano, rosemary, sage, anise, basil, etc., originate from the Mediterranean area. They contain many biologically active compounds, mainly polyphenolics, which have been found to possess antimicrobial, antioxidant, antiparasitic, antiprotozoal, antifungal, and anti-inflammatory properties. Currently, the demand for these plants and their derivatives has increased because they are natural, eco-friendly and generally recognized as safe products. Therefore, aromatic plants and their extracts have the potential to become new generation substances for human and animal nutrition and health. The purpose of this review is to provide an overview of the literature surrounding the in vivo and in vitro use of aromatic plants.

  9. Provisional Guidance for Quantitative Risk Assessment of Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    Polycyclic Aromatic Hydrocarbons (PAHs) are products of incomplete combustion of organic materials; sources are, thus, widespread,including cigarette smoke, municipal waste incineration, wood stove emissions, coal conversion, energy production form fossil fuels, and automobile an...

  10. Synthesis and characterization of organosoluble aromatic copolyimids

    Institute of Scientific and Technical Information of China (English)

    YANG Jintian; HUANG Wei; ZHOU Yongfeng; YAN Deyue

    2007-01-01

    A series of aromatic copolyimides was success fully synthesized from the commercial pyromellitic dianhy dride (PMDA) with a commercial diamine p-phenyldiamine (PDA) and a diamine 4,4'-methylenebis-(2-tert-butylaniline)(MBTBA) specially designed by the authors.The copoly imides were characterized by Infra-red (IR),Nuclear Magnetic Resonance (NMR),Gel Permeation Chromato graphy (GPC),Ultraviolet Visual (UV-Vis),Thermogra vimetic Analysis (TGA) and Dynamic Mechanical Analysis (DMA).The copolyimide was precipitated in m-cresol in the polymerization process when the molar ratio of MBTBA and PDA was lower than 6/4.The number-average molecular weight of the soluble copolyimides measured by GPC was larger than 4.0 x 104,and the polydispersity index was higher than 1.5.Only one glass transition temperature of these copolyimdies was detected around 360℃ by DMA.The copolyimides did not show appreciable decomposition up to 500℃ under N2,and the thermal stability of the copolyimide increased a little with the introduction of PDA into the polyimide main chain.

  11. Porphyrins Fused with Unactivated Polycyclic Aromatic Hydrocarbons

    KAUST Repository

    Diev, Vyacheslav V.

    2012-01-06

    A systematic study of the preparation of porphyrins with extended conjugation by meso,β-fusion with polycyclic aromatic hydrocarbons (PAHs) is reported. The meso-positions of 5,15-unsubstituted porphyrins were readily functionalized with PAHs. Ring fusion using standard Scholl reaction conditions (FeCl 3, dichloromethane) occurs for perylene-substituted porphyrins to give a porphyrin β,meso annulated with perylene rings (0.7:1 ratio of syn and anti isomers). The naphthalene, pyrene, and coronene derivatives do not react under Scholl conditions but are fused using thermal cyclodehydrogenation at high temperatures, giving mixtures of syn and anti isomers of the meso,β-fused porphyrins. For pyrenyl-substituted porphyrins, a thermal method gives synthetically acceptable yields (>30%). Absorption spectra of the fused porphyrins undergo a progressive bathochromic shift in a series of naphthyl (λ max = 730 nm), coronenyl (λ max = 780 nm), pyrenyl (λ max = 815 nm), and perylenyl (λ max = 900 nm) annulated porphyrins. Despite being conjugated with unsubstituted fused PAHs, the β,meso-fused porphyrins are more soluble and processable than the parent nonfused precursors. Pyrenyl-fused porphyrins exhibit strong fluorescence in the near-infrared (NIR) spectral region, with a progressive improvement in luminescent efficiency (up to 13% with λ max = 829 nm) with increasing degree of fusion. Fused pyrenyl-porphyrins have been used as broadband absorption donor materials in photovoltaic cells, leading to devices that show comparatively high photovoltaic efficiencies. © 2011 American Chemical Society.

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

    Science.gov (United States)

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

    2016-06-01

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

  13. Optimization of low ring polycylic aromatic biodegradation

    Science.gov (United States)

    Othman, N.; Abdul-Talib, S.; Tay, C. C.

    2016-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are recalcitrance and persistence that finally turn into problematic environmental contaminants. Microbial degradation is considered to be the primary mechanism of PAHs removal from the environment due to its organic criteria. This study is carried out to optimize degradation process of low ring PAHs. Bacteria used in this study was isolated from sludge collected from Kolej Mawar, Universiti Teknologi MARA, Shah Alam, Selangor. Working condition namely, substrate concentration, bacteria concentration, pH and temperature were optimized. PAHs in the liquid sample was extracted by using solid phase microextractio equipped with a 7 µm polydimethylsiloxane (PDMS) SPME fibr. Removal of PAHs were assessed by measuring PAHs concentration using GC-FID. Results from the optimization study of biodegradation indicated that maximum rate of PAHs removal occurred at 100 mgL-1 of PAHs, 10% bacteria concentration, pH 7.0 and 30°C. These working condition had proved the effectiveness of using bacteria in biodegradation process of PAHs.

  14. Polycyclic aromatic hydrocarbon molecules in astrophysics

    Science.gov (United States)

    Rastogi, Shantanu; Pathak, Amit; Maurya, Anju

    2013-06-01

    Polycyclic aromatic hydrocarbon (PAH) molecules are responsible for the mid-infrared emission features. Their ubiquitous presence in almost all types of astrophysical environments and related variations in their spectral profilesmake them an important tool to understand the physics and chemistry of the interstellar medium. The observed spectrum is generally a composite superposition of all different types of PAHs possible in the region. In the era of space telescopes the spectral richness of the emission features has enhanced their importance as probe and also the need to understand the variations with respect to PAH size, type and ionic state. Quantum computational studies of PAHs have proved useful in elucidating the profile variations and put constraints on the possible types of PAHs in different environments. The study of PAHs has also significantly contributed to the problems of diffuse interstellar bands (DIBs), UV extinction and understanding the chemistry of the formation of complex organics in space. The review highlights the results of various computational models for the understanding of infrared emission features, the PAH-DIB relation, formation of prebiotics and possible impact in the understanding of far-infrared features.

  15. Saudi decree encourages MTBE, Chevron aromatics plant

    International Nuclear Information System (INIS)

    Chevron Chemical (Houston), encouraged by a new Saudi royal decree that establishes extremely low feedstock prices, is in final negotiations to build a novel aromatics plant in Saudi Arabia. Chevron says it plans to close the deal and announce details the first week of March. The unit will be based on Chevron's Aromax reforming process, which uses a zeolite catalyst to convert light naphtha into benzene and toluene. No existing plant is using the technology, but Chevron is building a $250-million, 150-million gal/year Aromax unit at its refinery site in Pascagoula, MS, and Idemitsu has licensed the process for a plant in Chiba, Japan. The Saudi decree, issued late last year, pegs domestic feedstocks - propane, butane, and naphthas - at 30% below the lowest price of the prior quarter in major non-domestic markets. That clarifies and guarantees the Saudi feedstock price, which has always been nebulous, and thus allows project feasibility to be more clearly assessed. The decree is designed to encourage further private petrochemical investment in the country. In particular, the Saudi government hopes guaranteed low prices for butane will encourage more methyl tert-butyl ether (MTBE) projects. Arabian American Chemical, a 50/50 joint venture between Mobile and Arabian Chemical Investments, said in October of last year that its 830,000-m.t./year MTBE project at Yanbu, Saudi Arabia, would go ahead if feedstock questions could be resolved. The decree apparently resolves those questions

  16. Aromatizing unzipping polyester for EUV photoresist

    Science.gov (United States)

    Matsuzawa, Kensuke; Mesch, Ryan; Olah, Mike; Wang, Wade; Phillips, Scott T.; Willson, C. Grant

    2015-03-01

    New "self-immolating" or "unzipping" polymers, materials that depolymerize in response to irradiation, were designed and prepared successfully. We studied several candidate polymers and ultimately chose two of them for further development. One is a polyester that aromatizes upon depolymerization. The unzipping reaction initiated by UV exposure in solution was confirmed. The polymer was then studied in thin films to assess its potential for use in formulating photoresists. The neat polymer was tested as a blend with novolac resin. The effect of unzipping polyester loading in novolac on the rate of dissolution of films in TMAH was studied. Inhibition occurs at 20-30% loading. The films were exposed with DUV light and patterning was observed. The sensitivity of the unzipping polyester formulation is low in part due to the low absorption of the polymer for UV light. However, the polymer showed higher sensitivity with EUV exposure and first contrast curves show sensitivity in the range of 20-25mJ/cm2.

  17. Coassembly of aromatic dipeptides into biomolecular necklaces.

    Science.gov (United States)

    Yuran, Sivan; Razvag, Yair; Reches, Meital

    2012-11-27

    This paper describes the formation of complex peptide-based structures by the coassembly of two simple peptides, the diphenylalanine peptide and its tert-butyl dicarbonate (Boc) protected analogue. Each of these peptides can self-assemble into a distinct architecture: the diphenylalanine peptide into tubular structures and its analogue into spheres. Integrated together, these peptides coassemble into a construction of beaded strings, where spherical assemblies are connected by elongated elements. Electron and scanning force microscopy demonstrated the morphology of these structures, which we termed "biomolecular necklaces". Additional experiments indicated the reversibility of the coassembly process and the stability of the structures. Furthermore, we suggest a possible mechanism of formation for the biomolecular necklaces. Our suggestion is based on the necklace model for polyelectrolyte chains, which proposes that a necklace structure appears as a result of counterion condensation on the backbone of a polyelectrolyte. Overall, the approach of coassembly, demonstrated using aromatic peptides, can be adapted to any peptides and may lead to the development and discovery of new self-assembled architectures formed by peptides and other biomolecules. PMID:23061818

  18. Solubilities of solid polycyclic aromatic hydrocarbons and polycyclic aromatic heterocycles in pressurized hot water

    Czech Academy of Sciences Publication Activity Database

    Karásek, Pavel; Planeta, Josef; Roth, Michal

    Boulder, CO: National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA, 2006 - (Friend, D.; Frenkel, M.; Muzny, C.; Hardin, G.). s. 641-642 [International Conference on Chemical Thermodynamics /19./. THERMO International 2006. 30.07.2006-04.08.2006, Boulder, CO] R&D Projects: GA AV ČR IAA4031301; GA AV ČR KJB400310504; GA ČR GA203/05/2106 Keywords : aqueous solubility * pressurized hot water * polycyclic aromatic compounds Subject RIV: CF - Physical ; Theoretical Chemistry

  19. Response of Rice and Carbon Emission to Application of Ameliorant Dregs in The Peat Soil with Saturation and Unsaturation Condition

    Directory of Open Access Journals (Sweden)

    Nelvia Nelvia

    2014-01-01

    Full Text Available Fertility of peat land is very poor and makes it not suitable for crop without any high input.  This condition was indicated by the very high soil acidity ( low pH, low availability of macro (N, K, Ca and P, and micro (Cu, Zn, Mn and Bo nutriens and high cation exchange capacity (CEC but low base saturation (BS, the presence of toxic organic acid. The main organic acids, as a result of lignin biodegradation and the sources of C-release, are of aromatic group consisting mainly of derivate phenolic acids. The peat soil material was taken at depths from 0 to 30 cm, with weathering rate saprik and dregs from Indah Kiat Pulp and Paper at Perawang, Riau. These experiments using split plot design, the main plot is the condition of the water (unsaturated and saturated and the subplot is ameliorant dregs consisting of 4 levels (0, 10, 15 and 20 ton ha-1, each combination was repeated 4 times. The activities were focused on the interaction of water condition and ameliorant dregs, and its influences to growth and yield of rice, C-emission (CO2 and CH4. The results showed that the aplication of dregs improves plant growth and increase the yield of rice (weight of dry milled grain compared without dreg both at unsaturated condition and saturated conditions. The Cabon-release in the forms of CO2 and CH4 fluxes in saturated conditions is smaller than unsaturated conditions. The application dreg 10 t ha-1 increase the number of productive tillers and the weight of milled rice about 35 and 75% compared without dreg on saturated condition, whereas the increase is greater unsaturated conditions about 63 and 80%. The application of dregs 10 t ha-1 in saturated condition can reduce CO2 and CH4 emissions about 18.19% and 93.71% compared without dreg, otherwise the application dreg 10-20 t ha-1 increase the production of CO2 and CH4 in unsaturated conditions. 

  20. Measurement of Aromatic-hydrocarbons With the DOAS Technique

    OpenAIRE

    Axelsson, H; Eilard, A.; Emanuelsson, A.; Galle, B.; Edner, Hans; Ragnarson, P; Kloo, H

    1995-01-01

    Long-path DOAS (differential optical absorption spectroscopy) in the ultraviolet spectral region has been shown to be applicable for low-concentration measurements of light aromatic hydrocarbons. However, because of spectral interferences among different aromatics as well as with oxygen, ozone, and sulfur dioxide, the application of the DOAS technique for this group of components is not without problems. This project includes a study of the differential absorption characteristics, between 250...

  1. DNA-Catalyzed Hydrolysis of Esters and Aromatic Amides

    OpenAIRE

    Brandsen, Benjamin M.; Hesser, Anthony R.; Castner, Marissa A.; Chandra, Madhavaiah; Silverman, Scott K.

    2013-01-01

    We previously reported that DNA catalysts (deoxyribozymes) can hydrolyze DNA phosphodiester linkages, but DNA-catalyzed amide bond hydrolysis has been elusive. Here we used in vitro selection to identify DNA catalysts that hydrolyze ester linkages as well as DNA catalysts that hydrolyze aromatic amides, for which the leaving group is an aniline moiety. The aromatic amide-hydrolyzing deoxyribozymes were examined using linear free energy relationship analysis. The hydrolysis reaction is unaffec...

  2. Terahertz Spectroscopy of Biochars and Related Aromatic Compounds

    Science.gov (United States)

    Lepodise, L. M.; Horvat, J.; Lewis, R. A.

    2016-07-01

    A recent application of terahertz spectroscopy is to biochar, the agricultural charcoal produced by pyrolysis of various organic materials. Biochars simultaneously improve soil fertility and assist in carbon sequestration. Terahertz spectroscopy allows different biochars to be distinguished. However, the origin of the absorption features observed has not been clear. Given that biochar-based fertilizers are rich in aromatic compounds, we have investigated simple aromatic compounds as an approach to unravelling the complex biochar spectrum.

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

    OpenAIRE

    Ana Kroflič; Miha Grilc; Irena Grgić

    2015-01-01

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

  4. Shifting from Agriculture to Agribusiness: The Case of Aromatic Plants

    OpenAIRE

    Mittal, Rashi; Singh, S. P.

    2007-01-01

    This study has examined the agribusiness opportunities in medicinal and aromatic plants (MAPs), based on the field level information from the state of Uttarakhand. The financial feasibility of important aromatic plants has been studied. It has been found that the returns are substantially higher from these crops than the most profitable commercial crops like sugarcane. The study has identified the constraints that affect the spread of cultivation of MAPs; these include inadequate processing c...

  5. Aromatic Plants as a Source of Bioactive Compounds

    OpenAIRE

    Panagiota Florou-Paneri; Ilias Giannenas; Eleftherios Bonos; Efterpi Christaki

    2012-01-01

    Aromatic plants, also known as herbs and spices, have been used since antiquity as folk medicine and as preservatives in foods. The best known aromatic plants, such as oregano, rosemary, sage, anise, basil, etc., originate from the Mediterranean area. They contain many biologically active compounds, mainly polyphenolics, which have been found to possess antimicrobial, antioxidant, antiparasitic, antiprotozoal, antifungal, and anti-inflammatory properties. Currently, the demand for these plant...

  6. Collection and conservation of medicinal and aromatic plants resources

    OpenAIRE

    Z. Abraham

    2011-01-01

    (Abstract selected from presentation in National Conference on Biodiversity of Medicinal and Aromatic Plants: Collection, Characterization and Utilization, held at Anand, India during November 24-25, 2010)Plant genetic resources have made substantial contributions to the domestication, utilization and improvement of all kinds of crops including medicinal and aromatic plants. Collection, characterization and  their efficient utilization are keys to efficient management of any kind of genetic r...

  7. Aromatic amine dehydrogenase, a second tryptophan tryptophylquinone enzyme.

    OpenAIRE

    Govindaraj, S; Eisenstein, E.; Jones, L. H.; Sanders-Loehr, J; Chistoserdov, A Y; Davidson, V L; Edwards, S. L.

    1994-01-01

    Aromatic amine dehydrogenase (AADH) catalyzes the oxidative deamination of aromatic amines including tyramine and dopamine. AADH is structurally similar to methylamine dehydrogenase (MADH) and possesses the same tryptophan tryptophylquinone (TTQ) prosthetic group. AADH exhibits an alpha 2 beta 2 structure with subunit molecular weights of 39,000 and 18,000 and with a quinone covalently attached to each beta subunit. Neither subunit cross-reacted immunologically with antibodies to the correspo...

  8. Aromatic VOCs global influence in the ozone production

    Science.gov (United States)

    Cabrera-Perez, David; Pozzer, Andrea

    2016-04-01

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

  9. Impact of sample geometry on the measurement of pressure-saturation curves: Experiments and simulations

    Science.gov (United States)

    Moura, M.; Fiorentino, E.-A.; Mâløy, K. J.; Schäfer, G.; Toussaint, R.

    2015-11-01

    In this paper, we study the influence of sample geometry on the measurement of pressure-saturation relationships, by analyzing the drainage of a two-phase flow from a quasi-2-D random porous medium. The medium is transparent, which allows for the direct visualization of the invasion pattern during flow, and is initially saturated with a viscous liquid (a dyed glycerol-water mix). As the pressure in the liquid is gradually reduced, air penetrates from an open inlet, displacing the liquid which leaves the system from an outlet on the opposite side. Pressure measurements and images of the flow are recorded and the pressure-saturation relationship is computed. We show that this relationship depends on the system size and aspect ratio. The effects of the system's boundaries on this relationship are measured experimentally and compared with simulations produced using an invasion percolation algorithm. The pressure build up at the beginning and end of the invasion process are particularly affected by the boundaries of the system whereas at the central part of the model (when the air front progresses far from these boundaries), the invasion happens at a statistically constant capillary pressure. These observations have led us to propose a much simplified pressure-saturation relationship, valid for systems that are large enough such that the invasion is not influenced by boundary effects. The properties of this relationship depend on the capillary pressure thresholds distribution, sample dimensions, and average pore connectivity and its applications may be of particular interest for simulations of two-phase flow in large porous media.

  10. Thermal regeneration of activated carbons saturated with ortho- and meta-chlorophenols

    Energy Technology Data Exchange (ETDEWEB)

    Maroto-Valer, M. Mercedes [School of Chemical, Environmental and Mining Engineering, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Dranca, Ion; Clifford, David [The Energy Institute of the Penn State University, University Park, PA 16802 (United States); Lupascu, Tudor; Nastas, Raisa [Institute of Chemistry of the Academy of Sciences, Chisinau MD 2028 (Moldova, Republic of); Leon y Leon, Carlos A. [Quantachrome Instruments, Boynton Beach, FL 33426 (United States)

    2006-05-15

    Activated carbons (ACs) made from peach and plum stones were oxidized and impregnated with salts of Cu(II), Fe(III), Ni(II) and Cr(III). The chemically modified ACs, along with a commercial AC (S208c), were saturated with ortho- (OCP) and meta-chlorophenol (MCP) to investigate the potential for thermally regenerating the spent ACs. The thermal regeneration process was monitored by thermal analysis (TGA/DSC), gas chromatography and mass spectrometry (GC/MS). Thermal desorption profiles showed that in most cases weight losses occur in two steps (weak physisorption at circa 220{sup o}C and strong chemisorption at circa 620{sup o}C). Intermediate steps at circa 400{sup o}C appeared in samples whose chemical treatments successfully weakened the interactions between strongly chemisorbed chlorophenol (CP) molecules and AC surfaces. The type and quantity of products of OCP and MCP desorption during the thermal regeneration of a spent AC depend on the chemical modification given to the AC prior to its use as CP adsorbent. Besides the original chlorophenols, thermal regeneration products can include chlorobenzene, dichloro-dibenzofuran, phenol, aliphatic and aromatic hydrocarbons, water, chlorides, carbon oxides, hydrogen, and char deposits. Mechanisms for the formation of these compounds are discussed. The char deposits built during this study did not appear to diminish the surface area or porosity of the chemically modified ACs following their thermal regeneration. (author)

  11. Design of nanostructures based on aromatic peptide amphiphiles.

    Science.gov (United States)

    Fleming, Scott; Ulijn, Rein V

    2014-12-01

    Aromatic peptide amphiphiles are gaining popularity as building blocks for the bottom-up fabrication of nanomaterials, including gels. These materials combine the simplicity of small molecules with the versatility of peptides, with a range of applications proposed in biomedicine, nanotechnology, food science, cosmetics, etc. Despite their simplicity, a wide range of self-assembly behaviours have been described. Due to varying conditions and protocols used, care should be taken when attempting to directly compare results from the literature. In this review, we rationalise the structural features which govern the self-assembly of aromatic peptide amphiphiles by focusing on four segments, (i) the N-terminal aromatic component, (ii) linker segment, (iii) peptide sequence, and (iv) C-terminus. It is clear that the molecular structure of these components significantly influences the self-assembly process and resultant supramolecular architectures. A number of modes of assembly have been proposed, including parallel, antiparallel, and interlocked antiparallel stacking conformations. In addition, the co-assembly arrangements of aromatic peptide amphiphiles are reviewed. Overall, this review elucidates the structural trends and design rules that underpin the field of aromatic peptide amphiphile assembly, paving the way to a more rational design of nanomaterials based on aromatic peptide amphiphiles. PMID:25199102

  12. Aromatization of n-octane over Pd/C catalysts

    KAUST Repository

    Yin, Mengchen

    2013-01-01

    Gas-phase aromatization of n-octane was investigated using Pd/C catalyst. The objectives were to: (1) determine the effects of temperature (400-600 °C), weight hourly space velocity (WHSV) (0.8-∞), and hydrogen to hydrocarbon molar ratio (MR) (0-6) on conversion, selectivity, and yield (2) compare the activity of Pd/C with Pt/C and Pt/KL catalysts and (3) test the suitability of Pd/C for aromatization of different alkanes including n-hexane, n-heptane, and n-octane. Pd/C exhibited the best aromatization performance, including 54.4% conversion and 31.5% aromatics yield at 500 °C, WHSV = 2 h-1, and a MR of 2. The Pd/C catalyst had higher selectivity towards the preferred aromatics including ethylbenzene and xylenes, whereas Pt/KL had higher selectivity towards benzene and toluene. The results were somewhat consistent with adsorbed n-octane cyclization proceeding mainly through the six-membered ring closure mechanism. In addition, Pd/C was also capable of catalyzing aromatization of n-hexane and n-heptane. © 2012 Elsevier Ltd. All rights reserved.

  13. Detection of azo dyes and aromatic amines in women undergarment.

    Science.gov (United States)

    Nguyen, Thao; Saleh, Mahmoud A

    2016-07-28

    Women are exposed to several chemical additives including azo dyes that exist in textile materials, which are a potential health hazard for consumers. Our objective was to analyze suspected carcinogenic azo dyes and their degradation aromatic amines in women underwear panties using a fast and simple method for quantification. Here, we evaluated 120 different samples of women underwear for their potential release of aromatic amines to the skin. Seventy-four samples yielded low level mixtures of aromatic amines; however eighteen samples were found to produce greater than 200 mg/kg (ppm) of aromatic amines. Azo dyes in these 18 samples were extracted from the fabrics and analyzed by reverse phase thin layer chromatography in tandem with atmospheric pressure chemical ionization mass spectrometry. Eleven azo dyes were identified based on their mass spectral data and the chemical structure of the aromatic amine produced from these samples. We demonstrate that planar chromatography and mass spectrometry can be really helpful in confirming the identity of the azo dyes, offering highly relevant molecular information of the responsible compounds in the fabrics. With the growing concern about the consumer goods, analysis of aromatic amines in garments has become a highly important issue. PMID:27149414

  14. Saturation of Photoassociation in Cs Magneto-optical Trap

    Institute of Scientific and Technical Information of China (English)

    MA Jie; WANG Li-Rong; JI Wei-Bang; XIAO Lian-Tuan; JIA Suo-Tang

    2007-01-01

    An ultrahigh resolution photoassociation spectrum of caesium atoms in a magneto-optical trap is presented. Hyperfine structure of the excited state molecule is obtained by using the lock-in method based on modulated cold atoms in this spectrum. Amplitude of resonant lines related to the rotational levels increases with photoassociation laser intensity, and saturation effect of photoassociation of cold atoms is observed in our experiment. The saturation intensity of photoassociation is deduced by fitting the experimental data to a saturation model based on scattering theory. Differences among saturation intensities of different rotational progressions in the v = 55vibrational state of the caesium molecular long-range O-g state have been found.

  15. Saturated thickness of the Minnelusa aquifer, Black Hills, South Dakota.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set is a polygon coverage created in ARC/INFO that represents the saturated thickness of the Minnelusa aquifer, Black Hills area, South Dakota. The...

  16. Saturated thickness of the High Plains Aquifer, Colorado, 2000

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are in support of report DS 472 (Arnold and others, 2009). This data set represents the saturated thickness of the High Plains aquifer within Colorado....

  17. Saturated thickness of the Madison aquifer, Black Hills, South Dakota.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set is a polygon coverage created in ARC/INFO that represents the saturated thickness of the Madison aquifer, which includes the entire thickness of the...

  18. Soil hydraulic properties near saturation, an improved conductivity model

    DEFF Research Database (Denmark)

    Børgesen, Christen Duus; Jacobsen, Ole Hørbye; Hansen, Søren;

    2006-01-01

    The hydraulic properties near saturation can change dramatically due to the presence of macropores that are usually difficult to handle in traditional pore size models. The purpose of this study is to establish a data set on hydraulic conductivity near saturation, test the predictive capability...... of commonly used hydraulic conductivity models and give suggestions for improved models. Water retention and near saturated and saturated hydraulic conductivity were measured for a variety of 81 top and subsoils. The hydraulic conductivity models by van Genuchten [van Genuchten, 1980. A closed-form equation...... for predicting the hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J. 44, 892–898.] (vGM) and Brooks and Corey, modified by Jarvis [Jarvis, 1991. MACRO—A Model of Water Movement and Solute Transport in Macroporous Soils. Swedish University of Agricultural Sciences. Department of Soil Sciences...

  19. Pore capillary pressure and saturation of methane hydrate bearing sediments

    Institute of Scientific and Technical Information of China (English)

    SUN Shicai; LIU Changling; YE Yuguang; LIU Yufeng

    2014-01-01

    To better understand the relationship between the pore capillary pressure and hydrate saturation in sedi-ments, a new method was proposed. First, the phase equilibria of methane hydrate in fine-grained silica sands were measured. As to the equilibrium data, the pore capillary pressure and saturation of methane hydrate were calculated. The results showed that the phase equilibria of methane hydrates in fine-grained silica sands changed due to the depressed activity of pore water caused by the surface group and negatively charged characteristic of silica particles as well as the capillary pressure in small pores together. The capil-lary pressure increased with the increase of methane hydrate saturation due to the decrease of the available pore space. However, the capillary-saturation relationship could not yet be described quantitatively because of the stochastic habit of hydrate growth.

  20. Solid-state lamps with optimized color saturation ability.

    Science.gov (United States)

    Zukauskas, Artūras; Vaicekauskas, Rimantas; Shur, Michael

    2010-02-01

    Spectral power distribution of trichromatic clusters of light-emitting diodes (LEDs) was optimized for rendering the highest number of colors with a perceptually noticeable gain in chroma (color saturation) out of 1269 Munsell samples. The basic tradeoffs of the number of colors rendered with increased saturation with the number of colors rendered with high fidelity and with luminous efficacy of radiation were established. High-saturation RGB clusters composed of commercially available AlGaInP and InGaN LEDs were modeled for a standard set of correlated color temperatures and the stability of the color saturation ability of the clusters against the drift of peak wavelengths was investigated. PMID:20174057

  1. Saturation wind power potential and its implications for wind energy

    OpenAIRE

    Jacobson, Mark Z.; Cristina L. Archer

    2012-01-01

    Wind turbines convert kinetic to electrical energy, which returns to the atmosphere as heat to regenerate some potential and kinetic energy. As the number of wind turbines increases over large geographic regions, power extraction first increases linearly, but then converges to a saturation potential not identified previously from physical principles or turbine properties. These saturation potentials are >250 terawatts (TW) at 100 m globally, approximately 80 TW at 100 m over land plus coastal...

  2. Saturated tearing modes in tokamaks. Renewal proposal, progress report

    International Nuclear Information System (INIS)

    We have completed a computer code (GTOR) implementing our quasilinear method for determining saturated tearing mode magnetic island widths in axisymmetric toroidal plasmas. With this code we have surveyed the effect of current profile, aspect ratio and plasma elongation on saturated tearing modes. Current peaking within the islands is found to have a particularly large effect. In support of this research, we have developed a direct method for computing Hamada coordinates from harmonics of the inverse Grad-Shafranov equation

  3. Pulse Distortion in Saturated Fiber Optical Parametric Chirped Pulse Amplification

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Da Ros, Francesco; Rottwitt, Karsten;

    2012-01-01

    Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation.......Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation....

  4. Law of nonlinear flow in saturated clays and radial consolidation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    It was derived that micro-scale amount level of average pore radius of clay changed from 0.01 to 0.1 micron by an equivalent concept of flow in porous media. There is good agreement between the derived results and test ones. Results of experiments show that flow in micro-scale pore of saturated clays follows law of nonlinear flow. Theoretical analyses demonstrate that an interaction of solid-liquid interfaces varies inversely with permeability or porous radius. The interaction is an important reason why nonlinear flow in saturated clays occurs. An exact mathematical model was presented for nonlinear flow in micro-scale pore of saturated clays. Dimension and physical meanings of parameters of it are definite. A new law of nonlinear flow in saturated clays was established. It can describe characteristics of flow curve of the whole process of the nonlinear flow from low hydraulic gradient to high one. Darcy law is a special case of the new law. A mathematical model was presented for consolidation of nonlinear flow in radius direction in saturated clays with constant rate based on the new law of nonlinear flow. Equations of average mass conservation and moving boundary, and formula of excess pore pressure distribution and average degree of consolidation for nonlinear flow in saturated clay were derived by using an idea of viscous boundary layer, a method of steady state in stead of transient state and a method of integral of an equation. Laws of excess pore pressure distribution and changes of average degree of consolidation with time were obtained. Results show that velocity of moving boundary decreases because of the nonlinear flow in saturated clay. The results can provide geology engineering and geotechnical engineering of saturated clay with new scientific bases. Calculations of average degree of consolidation of the Darcy flow are a special case of that of the nonlinear flow.

  5. Noise and saturation properties of semiconductor quantum dot optical amplifiers

    DEFF Research Database (Denmark)

    Berg, Tommy Winther; Mørk, Jesper

    2002-01-01

    We present a detailed theoretical analysis of quantum dot optical amplifiers. Due to the presence of a reservoir of wetting layer states, the saturation and noise properties differ markedly from bulk or QW amplifiers and may be significantly improved.......We present a detailed theoretical analysis of quantum dot optical amplifiers. Due to the presence of a reservoir of wetting layer states, the saturation and noise properties differ markedly from bulk or QW amplifiers and may be significantly improved....

  6. Study of haemoglobin saturation with Mössbauer spectroscopy

    Science.gov (United States)

    Ortalli, I.; Pedrazzi, G.; Mangoni, L.; Rizzoli, V.

    1988-10-01

    Red blood cells from normal subjects, Hodgkin's lymphoma and acute leukaemia have been investigated. Preliminary Mössbauer spectroscopy results in seven patients have shown a high haedmoglobin saturation. Independent measurements of pH, pCO2, pO2, DPG and P50, are in agreement with the Mössbauer data. These results give indication that the evaluation of haemoglobin saturation could be an information to be used in the clinical follow up of these hematological malignancies.

  7. Saturated locally optimal designs under differentiable optimality criteria

    OpenAIRE

    Hu, Linwei; Yang, Min; Stufken, John

    2014-01-01

    We develop general theory for finding locally optimal designs in a class of single-covariate models under any differentiable optimality criterion. Yang and Stufken [Ann. Statist. 40 (2012) 1665–1681] and Dette and Schorning [Ann. Statist. 41 (2013) 1260–1267] gave complete class results for optimal designs under such models. Based on their results, saturated optimal designs exist; however, how to find such designs has not been addressed. We develop tools to find saturated optimal designs, and...

  8. Nonlinear Gain Saturation in Active Slow Light Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2013-01-01

    We present a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguides. The impact of slow-light propagation on the nonlinear gain saturation of the device is investigated.......We present a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguides. The impact of slow-light propagation on the nonlinear gain saturation of the device is investigated....

  9. Simulation of Nonlinear Gain Saturation in Active Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2012-01-01

    In this paper we present a theoretical analysis of slowlight enhanced traveling wave amplification in an active semiconductor Photonic crystal waveguides. The impact of group index on nonlinear modal gain saturation is investigated.......In this paper we present a theoretical analysis of slowlight enhanced traveling wave amplification in an active semiconductor Photonic crystal waveguides. The impact of group index on nonlinear modal gain saturation is investigated....

  10. Aromatic stacking between nucleobase and enzyme promotes phosphate ester hydrolysis in dUTPase

    OpenAIRE

    Pecsi, Ildiko; Leveles, Ibolya; Harmat, Veronika; Vertessy, Beata G.; Toth, Judit

    2010-01-01

    Aromatic interactions are well-known players in molecular recognition but their catalytic role in biological systems is less documented. Here, we report that a conserved aromatic stacking interaction between dUTPase and its nucleotide substrate largely contributes to the stabilization of the associative type transition state of the nucleotide hydrolysis reaction. The effect of the aromatic stacking on catalysis is peculiar in that uracil, the aromatic moiety influenced by the aromatic interac...

  11. Graphene-clad microfibre saturable absorber for ultrafast fibre lasers

    Science.gov (United States)

    Liu, X. M.; Yang, H. R.; Cui, Y. D.; Chen, G. W.; Yang, Y.; Wu, X. Q.; Yao, X. K.; Han, D. D.; Han, X. X.; Zeng, C.; Guo, J.; Li, W. L.; Cheng, G.; Tong, L. M.

    2016-05-01

    Graphene, whose absorbance is approximately independent of wavelength, allows broadband light–matter interactions with ultrafast responses. The interband optical absorption of graphene can be saturated readily under strong excitation, thereby enabling scientists to exploit the photonic properties of graphene to realize ultrafast lasers. The evanescent field interaction scheme of the propagating light with graphene covered on a D-shaped fibre or microfibre has been employed extensively because of the nonblocking configuration. Obviously, most of the fibre surface is unused in these techniques. Here, we exploit a graphene-clad microfibre (GCM) saturable absorber in a mode-locked fibre laser for the generation of ultrafast pulses. The proposed all-surface technique can guarantee a higher efficiency of light–graphene interactions than the aforementioned techniques. Our GCM-based saturable absorber can generate ultrafast optical pulses within 1.5 μm. This saturable absorber is compatible with current fibre lasers and has many merits such as low saturation intensities, ultrafast recovery times, and wide wavelength ranges. The proposed saturable absorber will pave the way for graphene-based wideband photonics.

  12. The relation between oxygen saturation level and retionopathy of prematurity

    Directory of Open Access Journals (Sweden)

    Mohammad Gharavi Fard

    2016-03-01

    Full Text Available Introduction: Oxygen therapy used for preterm infant disease might be associated with oxygen toxicity or oxidative stress. The exact oxygen concentration to control and maintain the arterial oxygen saturation balance is not certainly clear. We aimed to compare the efficacy of higher or lower oxygen saturations on the development of severe retinopathy of prematurity which is a major cause of blindness in preterm neonates. Methods: PubMed was searched for obtaining the relevant articles. A total of seven articles were included after studying the titles, abstracts, and the full text of retrieved articles at initial search. Inclusion criteria were all the English language human clinical randomized controlled trials with no time limitation, which studied the efficacy of low versus high oxygen saturation measured by pulse oximetry in preterm infants.Result: It can be suggested that lower limits of oxygen saturations have higher efficacy at postmesetural age of ≤28 weeks in preterm neonates. This relation has been demonstrated in five large clinical trials including three Boost trials, COT, and Support.Discussion: Applying higher concentrations of oxygen supplementations at mesentural age ≥32 weeks reduced the development of retinopathy of prematurity. Lower concentrations of oxygen saturation decreased the incidence and the development of retinopathy of prematurity in preterm neonates while applied soon after the birth.Conclusions: Targeting levels of oxygen saturation in the low or high range should be performed cautiously with attention to the postmesentural age in preterm infants at the time of starting the procedures.

  13. Graphene-clad microfibre saturable absorber for ultrafast fibre lasers.

    Science.gov (United States)

    Liu, X M; Yang, H R; Cui, Y D; Chen, G W; Yang, Y; Wu, X Q; Yao, X K; Han, D D; Han, X X; Zeng, C; Guo, J; Li, W L; Cheng, G; Tong, L M

    2016-01-01

    Graphene, whose absorbance is approximately independent of wavelength, allows broadband light-matter interactions with ultrafast responses. The interband optical absorption of graphene can be saturated readily under strong excitation, thereby enabling scientists to exploit the photonic properties of graphene to realize ultrafast lasers. The evanescent field interaction scheme of the propagating light with graphene covered on a D-shaped fibre or microfibre has been employed extensively because of the nonblocking configuration. Obviously, most of the fibre surface is unused in these techniques. Here, we exploit a graphene-clad microfibre (GCM) saturable absorber in a mode-locked fibre laser for the generation of ultrafast pulses. The proposed all-surface technique can guarantee a higher efficiency of light-graphene interactions than the aforementioned techniques. Our GCM-based saturable absorber can generate ultrafast optical pulses within 1.5 μm. This saturable absorber is compatible with current fibre lasers and has many merits such as low saturation intensities, ultrafast recovery times, and wide wavelength ranges. The proposed saturable absorber will pave the way for graphene-based wideband photonics. PMID:27181419

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

    International Nuclear Information System (INIS)

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

  15. Aromatic and hetero-aromatic compositional changes during catalytic treatment of shale oil

    Energy Technology Data Exchange (ETDEWEB)

    Chishti, H.M.; Williams, P.T. [University of Leeds, Leeds (United Kingdom). Dept. of Fuel and Energy

    1999-12-01

    Oil shale from the Kimmeridge Clay, of Jurassic age from the UK was pyrolysed in a 5 kg fixed bed reactor at 525{degree}C in a nitrogen atmosphere. The derived shale oil was then hydrotreated at 15.0 MPa pressure and 400{degree}C in a stirred reactor with a nickel-molybdenum (Ni-Mo) catalyst and residence times from 8 to 56 h. The shale oils were analysed for polycyclic aromatic hydrocarbons (PAH) and for nitrogen PAH (PANH) and sulphur-PAH (PASH), before and after hydrotreatment. The results showed that generally the higher molecular weight three and four ring PAH decreased with increasing hydrotreatment time, however, single ring aromatic compounds and two ring PAH were increased. Nitrogen and sulphur containing PAH were significantly reduced in concentration in the oils with increasing hydrotreatment time to reach negligible concentrations after 56 h. The reduction in PANH and PASH coincided with a reduction in the overall nitrogen and sulphur contents of the oils. 37 refs.

  16. Arginine-aromatic interactions and their effects on arginine-induced solubilization of aromatic solutes and suppression of protein aggregation

    KAUST Repository

    Shah, Dhawal

    2011-09-21

    We examine the interaction of aromatic residues of proteins with arginine, an additive commonly used to suppress protein aggregation, using experiments and molecular dynamics simulations. An aromatic-rich peptide, FFYTP (a segment of insulin), and lysozyme and insulin are used as model systems. Mass spectrometry shows that arginine increases the solubility of FFYTP by binding to the peptide, with the simulations revealing the predominant association of arginine to be with the aromatic residues. The calculations further show a positive preferential interaction coefficient, Γ XP, contrary to conventional thinking that positive Γ XP\\'s indicate aggregation rather than suppression of aggregation. Simulations with lysozyme and insulin also show arginine\\'s preference for aromatic residues, in addition to acidic residues. We use these observations and earlier results reported by us and others to discuss the possible implications of arginine\\'s interactions with aromatic residues on the solubilization of aromatic moieties and proteins. Our results also highlight the fact that explanations based purely on Γ XP, which measures average affinity of an additive to a protein, could obscure or misinterpret the underlying molecular mechanisms behind additive-induced suppression of protein aggregation. © 2011 American Institute of Chemical Engineers (AIChE).

  17. Partition of polycyclic aromatic hydrocarbons on organobentonites

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

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

  18. Fate of polynuclear aromatic hydrocarbons in soil

    International Nuclear Information System (INIS)

    A study was performed on the persistence of selected polynuclear aromatic hydrocarbons (PAH's) in soil. Two incubation studies were performed. In the first, a mixture of eight PAH's were added to unacclimated soil at levels of 5 and 50 mg/kg and the concentrations were monitored with time. In the second, C14-labelled benzo(a)pyrene or anthracene was added to soil incubated in biometer flasks. Microbial degradation, physical and chemical degradation, volatilization and binding were assessed as mechanisms affecting benzo(a)pyrene and anthracene in soil. The disappearance of PAH's appeared to be related to molecular weight, water solubility, volatility and adsorptivity to soil. The loss during this initial period approximated first order kinetics, in some cases following a lag period. The remaining 2-6% of the added PAH's, however, was lost at a much reduced rate. With the 50 mg/kg level of application, reduced rates of disappearance in later stages resulted in levels five to ten times the background concentration which persisted throughout the 400 days. Degradation of phenanthrene, anthracene, fluoranthene and pyrene at the 5 mg/kg application rate, however, resulted in concentrations close to background levels within 400 days. Either a model other than first order or a combination of two models was required to adequately describe the loss of 99% of the added PAH's. The mechanisms leading to a decrease in PAH concentration, identified through the use of C14 labelling, were predominantly volatilization and adsorption to soil solids for anthracene and adsorption to soil solids for benzo(a)pyrene. Microbial transformation of benzo(a)pyrene was minimal. 17 refs., 10 figs., 4 tabs

  19. Numerical modelling of multicomponent LNAPL dissolution kinetics at residual saturation in a saturated subsurface system

    Indian Academy of Sciences (India)

    M Vasudevan; G Suresh Kumar; Indumathi M Nambi

    2014-12-01

    Characterization of aquifers contaminated by petroleum hydrocarbons is limited by the use of dissolution mass transfer correlations developed for single compounds without considering the effects of the mass transfer limitations in presence of other components. A one-dimensional implicit numerical model is developed for the coupled mass transfer and transport processes and the results are analysed using existing mass transfer correlations for better understanding of the single and multicomponent dissolution processes. Themass transfer coefficient in the multicomponent system is found to be more nonlinear and extending with changing slope, unlike the exponential reduction for single compound system. During the initial phase, the dissolution rate of a soluble compound is very high due to the high concentration gradient, and as dissolution progresses, its effective solubility decreases with change in mole fraction. At higher pore volumes, the mole fractions of lower solubility fractions increase which can result in higher effective solubility. The kinetics of interphase mass transfer by dissolution and sorption is favoured by coupled biodegradation. However, mass transfer limitation for more soluble compounds under the conditions of low residual saturation and low mole fraction is observed to be due to low dissolution rate coefficient rather than decreasing concentration gradient.

  20. Molybdenite saturation in silicic magmas: Occurrence and petrological implications

    Science.gov (United States)

    Audetat, A.; Dolejs, D.; Lowenstern, J. B.

    2011-01-01

    We identified molybdenite (MoS2) as an accessory magmatic phase in 13 out of 27 felsic magma systems examined worldwide. The molybdenite occurs as small (<20 ??m) triangular or hexagonal platelets included in quartz phenocrysts. Laser-ablation inductively coupled plasma mass spectrometry analyses of melt inclusions in molybdenite-saturated samples reveal 1-13 ppm Mo in the melt and geochemical signatures that imply a strong link to continental rift basalt-rhyolite associations. In contrast, arc-associated rhyolites are rarely molybdenite-saturated, despite similar Mo concentrations. This systematic dependence on tectonic setting seems to reflect the higher oxidation state of arc magmas compared with within-plate magmas. A thermodynamic model devised to investigate the effects of T, f O2 and f S2 on molybdenite solubility reliably predicts measured Mo concentrations in molybdenite-saturated samples if the magmas are assumed to have been saturated also in pyrrhotite. Whereas pyrrhotite microphenocrysts have been observed in some of these samples, they have not been observed from other molybdenite-bearing magmas. Based on the strong influence of f S2 on molybdenite solubility we calculate that also these latter magmas must have been at (or very close to) pyrrhotite saturation. In this case the Mo concentration of molybdenite-saturated melts can be used to constrain both magmatic f O2 and f S2 if temperature is known independently (e.g. by zircon saturation thermometry). Our model thus permits evaluation of magmatic f S2, which is an important variable but is difficult to estimate otherwise, particularly in slowly cooled rocks. ?? The Author 2011. Published by Oxford University Press. All rights reserved.

  1. Elastic laboratory measurements and modeling of saturated basalts

    Science.gov (United States)

    Adam, Ludmila; Otheim, Thomas

    2013-03-01

    Understanding the elastic behavior of basalt is important to seismically monitor volcanoes, subsea basalts, and carbon sequestration in basalt. We estimate the elastic properties of basalt samples from the Snake River Plain, Idaho, at ultrasonic (0.8 MHz) and seismic (2-300 Hz) frequencies. To test the sensitivity of seismic waves to the fluid content in the pore structure, measurements are performed at three saturation conditions: saturated with liquid CO2, water, and dry. When CO2 replaces water, the P-wave velocity drops, on average, by 10%. Vesicles and cracks, observed in the rock microstructure, control the relaxation of pore-fluid pressures in the rock as a wave propagates. The bulk and shear moduli of basalts saturated with liquid CO2 are not frequency dependent, suggesting that fluid pore pressures are in equilibrium between 2 Hz and 0.8 MHz. However, when samples are water saturated, the bulk modulus of the rock is frequency dependent. Modeling with Gassmann's equations predicts the measured saturated rock bulk modulus for all fluids for frequencies below 20 Hz but underpredicts the water-saturated basalt bulk modulus for frequencies greater than 20 Hz. The most likely reason is that the pore-fluid pressures are unrelaxed. Instead, the ultrasonic frequency rock moduli are modeled with high-frequency elastic theories of squirt flow and Kuster-Toksöz (KT). Although KT's model is based on idealized pore shapes, a combination of spheres (vesicles) and penny-shaped cracks (fractures) interpreted and quantified from petrographical data predicts the ultrasonic dry and saturated rock moduli for the measured basalts.

  2. POLYCYCLIC AROMATIC HYDROCARBON FAR-INFRARED SPECTROSCOPY

    International Nuclear Information System (INIS)

    The far-IR characteristics of astrophysically relevant polycyclic aromatic hydrocarbons (PAHs) averaging in size around 100 carbon atoms have been studied using the theoretical spectra in the NASA Ames PAH IR Spectroscopic Database. These spectra were calculated using density functional theory. Selections of PAH species are made, grouped together by common characteristics or trends, such as size, shape, charge, and composition, and their far-IR spectra compared. The out-of-plane modes involving the entire molecule are explored in detail, astronomical relevance is assessed, and an observing strategy is discussed. It is shown that PAHs produce richer far-IR spectra with increasing size. PAHs also produce richer far-IR spectra with increasing number of irregularities. However, series of irregular-shaped PAHs with the same compact core have common 'Jumping-Jack' modes that 'pile up' at specific frequencies in their average spectrum. For the PAHs studied here, around 100 carbon atoms in size, this band falls near 50 μm. PAH charge and nitrogen inclusion affect band intensities but have little effect on far-IR band positions. Detailed analysis of the two-dimensional, out-of-plane bending 'drumhead' modes in the coronene and pyrene 'families' and the one-dimensional, out-of-plane bending 'bar' modes in the acene 'family' show that these molecular vibrations can be treated as classical vibrating sheets and bars of graphene, respectively. The analysis also shows that the peak position of these modes is very sensitive to the area of the emitting PAH and does not depend on the particular geometry. Thus, these longest wavelength PAH bands could provide a unique handle on the size of the largest species in the interstellar PAH family. However, these bands are weak. Observing highly excited regions showing the mid-IR bands in which the emission from classical dust peaks at short wavelengths offers the best chance of detecting PAH emission in the far-IR. For these regions

  3. Experimental investigation of saturated polarization spectroscopy for quantatative concentration measurements

    International Nuclear Information System (INIS)

    Polarization-spectroscopy (PS) line shapes and signal intensities are measured in well-characterized hydrogen-air flames operated over a wide range of equivalence ratios. We use both low (perturbative) and high (saturating) pump beam intensities in the counterpropagating pump-probe geometry. The effects of saturation on the line-center signal intensity and the resonance linewidth are investigated. The PS signal intensities are used to measure relative OH number densities in a series of near-adiabatic flames at equivalence ratios (φ) ranging from 0.5 to 1.5. The use of saturating pump intensities minimizes the effect of pump beam absorption, providing more accurate number density measurements. When calibrated to the calculated OH concentration in the φ=0.6 flame, the saturated PS number density measurements probing the P1(2) transition are in excellent agreement with OH absorption measurements, equilibrium calculations of OH number density, and previous saturated degenerate four-wave mixing OH number density measurements. (c) 2000 Optical Society of America

  4. RESEARCH METHODS OF SATURATED VAPOR PRESSURE AND EXPERIMENTAL INSTALLATIONS

    Directory of Open Access Journals (Sweden)

    Kharchenko P. M.

    2015-02-01

    Full Text Available The static method is the most common, because it is applicable for measuring SVP of substances in wide ranges of temperatures and pressures. The essence of the method consists in measuring of vapor pressure in equilibrium with its liquid at a given temperature. Dynamic method is based on measurement of the boiling point of the liquid at a certain pressure. Saturation method of moving gas used in the case when the SVP does not exceed a few mm Hg. The method consists the following: the liquid is passed through the inert gas and saturated with vapor of liquids and then it flows into a cooler where the absorbed vapors are condensed. Knowing the amount of absorbed liquid and gas, as well as their molecular weight, allow us calculate saturated vapor pressure of the liquid. Knudsen effusion method is applicable for the measurement of very low pressures (up to 100 Pa. This method consists in researching of depending between the pressure and volume of saturated steam at a constant temperature. At the point of saturation an isotherm should have a break and turn into a straight line. Chromatographic method is based on complete chromatographic analysis of liquid and calculating the sum of partial pressures of all mixture components. Also, the article has a description of existing experimental installation for these researches and their advantages and disadvantages compared with each other

  5. Gaseous saturable absorbers for the Helios CO2 laser system

    International Nuclear Information System (INIS)

    Saturable absorbers are widely used to suppress parasitic oscillations in large-aperture, high-power CO2 fusion-laser systems. We report experimental results on SF6-based gaseous saturable absorbers used for parasitic suppression in the eight-beam, 10 kJ Helios fusion-laser system. The gas mix effectively quenches self-lasing in the 9 and 10 μm branches of the CO2 laser spectrum while simultaneously allowing high transmission of subnanosecond multiwavelength pulses for target-irradiation experiments. The gas isolator now in use consists of SF6 and the additional fluorocarbons: 1, 1-difluoroethane (FC-152a); dichlorodifluoromethane (FC-12); chloropentafluoroethane (FC-115); 1,1-dichloro 2,2-difluoroethylene (FC-1112a); chlorotrifluoroethylene (FC-1113); and perfluorocyclobutane (FC-C318). The saturation of the mix was studied as a function of incident fluence, pressure, cell length, and incident wavelength. Experimental results are presented on the saturation properties of pure SF6 and FC-152a and compared with the saturation behavior of CO2 at 4000C

  6. Transport of engineered nanoparticles in partially saturated sand columns.

    Science.gov (United States)

    Yecheskel, Yinon; Dror, Ishai; Berkowitz, Brian

    2016-07-01

    The vadose zone is a critical region controlling fate and transport of contaminants in soils and, ultimately, groundwater. It is therefore important to understand the behavior of engineered nanoparticles (ENPs) in this zone, as a potential group of emerging contaminants. Soil is a significant sink for ENPs; however, only a few studies have considered the fate and transport of ENPs in partially saturated systems, representative of the vadose zone. Here, transport behavior of three commonly used ENPs - gold (Au-NPs), silver (Ag-NPs) and zinc oxide (ZnO-NPs) - is investigated in partially saturated sand columns. High mobilities of Au-NPs and Ag-NPs under different water saturation levels and concentrations were observed. The presence of CaCl2 reduces Ag-NP mobility through chemical interactions, similar to behavior reported in saturated systems. Furthermore, transformation of Ag-NPs in the environment may influence their mobility; aging of Ag-NPs following sulfidation was investigated. The silver sulfide (Ag2S-NPs) remained stable in aqueous suspension, and mobile in the partially saturated sand column. In contrast, the positively-charged ZnO-NPs were completely immobilized in the sand column. Significantly, though, addition of humic acid (HA) to the ZnO-NP suspension reverses particle surface charge and thus increases their mobility. Moreover, remobilization of entrapped ZnO-NPs by HA was demonstrated. PMID:26995325

  7. Oxygen saturation limits and evidence supporting the targets.

    Science.gov (United States)

    Newnam, Katherine M

    2014-12-01

    Supplemental oxygen use in the preterm infant is required for survival. Evidence supports a narrow therapeutic window between the helpful and harmful effects of supplemental oxygen in this vulnerable population. The clinical question was-what are the recommended oxygen saturation targets for the preterm infant and the preterm infant corrected to term? Multiple databases were searched for published research in English from 2008 to 2014 using key search terms. A total of 18 articles met inclusion criteria. Early neonatal research linked high levels of supplemental oxygen with retinopathy of prematurity and blindness. Years later, correlations between high arterial oxygen levels and oxidative stress leading to pulmonary and/or neurologic insults were established. Three large multicentered, international studies have recently been published (BOOST II, COT, and SUPPORT), which support oxygen saturation target ranges of 87% to 94% until vascular maturation of the retina is achieved. Two of the 3 studies reported a significant correlation between low saturation limits (85%-89%) and death in the extremely preterm population. Identified best care strategies to prevent states of hypoxia and/or hyperoxia include establishing clear target saturation limits according to recommendations, which are supported by the multidisciplinary team, adequate nurse to patient ratio, improve knowledge deficits, improve bedside compliance, and finally visual cues to remind caregivers of target saturation ranges. PMID:25422926

  8. 3-D DYNAMIC RESPONSE OF TRANSVERSELY ISOTROPIC SATURATED SOILS

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-gang; HUANG Yi

    2005-01-01

    A study on dynamic response of transversely isotropic saturated poroelastic media under a circular non-axisymmetrical harmonic source has been presented by Huang Yi et al.using the technique of Fourier expansion and Hankel transform. However, the method may not always be valid. The work is extended to the general case being in the rectangular coordinate. The purpose is to study the 3-d dynamic response of transversely isotropic saturated soils under a general source distributing in arbitrary rectangular zoon on the medium surface. Based on Biot's theory for fluid-saturated porous media, the 3-d wave motion equations in rectangular coordinate for transversely isotropic saturated poroelastic media were transformed into the two uncoupling governing differential equations of 6-order and 2-order respectively by means of the displacement functions. Then, using the technique of double Fourier transform, the governing differential equations were easily solved. Integral solutions of soil skeleton displacements and pore pressure as well as the total stresses for poroelastic media were obtained. Furthermore, a systematic study on half-space problem in saturated soils was performed. Integral solutions for surface displacements under the general harmonic source distributing on arbitrary surface zone,considering both case of drained surface and undrained surface,were presented.

  9. (Hetero)aromatics from dienynes, enediynes and enyne-allenes.

    Science.gov (United States)

    Raviola, Carlotta; Protti, Stefano; Ravelli, Davide; Fagnoni, Maurizio

    2016-08-01

    The construction of aromatic rings has become a key objective for organic chemists. While several strategies have been developed for the functionalization of pre-formed aromatic rings, the direct construction of an aromatic core starting from polyunsaturated systems is yet a less explored field. The potential of such reactions in the formation of aromatics increased at a regular pace in the last few years. Nowadays, there are reliable and well-established procedures to prepare polyenic derivatives, such as dienynes, enediynes, enyne-allenes and hetero-analogues. This has stimulated their use in the development of innovative cycloaromatizations. Different examples have recently emerged, suggesting large potential of this strategy in the preparation of (hetero)aromatics. Accordingly, this review highlights the recent advancements in this field and describes the different conditions exploited to trigger the process, including thermal and photochemical activation, as well as the use of transition metal catalysis and the addition of electrophiles/nucleophiles or radical species. PMID:27263976

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-02-01

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

  11. A photochemical approach to aromatic extension of the corannulene nucleus.

    Science.gov (United States)

    Rajeshkumar, Venkatachalam; Stuparu, Mihaiela C

    2016-08-01

    A high yielding, general, and mild synthetic strategy is established for aromatic annulation of the corannulene scaffold. In this approach, a corannulene-based aldehyde, ylide, or ketone compound is conjugated with an aromatic unit of choice through a Wittig reaction. The resulting stilbene-like precursor can be subjected to a photochemically induced oxidative-cyclization process to yield a corannulene structure with an extended π-framework. The generality of synthesis allows for preparation of a wide range of polycyclic aromatic arene as well as heteroarene structures. Meanwhile, the mild nature of the developed protocol permits for incorporation of reactive and functional substituents onto the fused aromatic scaffold. Furthermore, efficient and simple synthesis ensures access to significant amounts of the material in a facile manner. In essence, this work demonstrates, for the first time, that photochemical synthesis is a highly practical alternative to the known flash vacuum pyrolysis and metal catalyzed processes for the aromatic extension of the bucky-bowl structure. PMID:27440449

  12. Genetic Variability in Bangladeshi Aromatic Rice through RAPD Analysis

    Directory of Open Access Journals (Sweden)

    Mehfuz Hasan

    2014-10-01

    Full Text Available Genetic polymorphism and relationships among 30 commercial varieties of Bangladeshi aromatic rice (Oryza sativa L. were established using random amplified polymorphic DNA (RAPD primers. Out of fifty 10-mer RAPD primers screened initially, four were chosen and used in a comparative analysis of different varieties of indigenous Bangladeshi aromatic rice. Of the 33 total RAPD fragments amplified, 7 (21.21% were found to be shared by individuals of all eight varieties. The remaining 26 fragments were found to be polymorphic (78.79%. Pair-wise estimates of similarity ranged from 0.101 to 0.911. Highest genetic diversity was determined between Radhunipagol and Dubsail varieties (0.911. The amount of genetic diversity within aromatic rice germplasm was quite high as determined by the genetic similarity coefficients between varieties. Genetic similarities obtained from RAPD data were also used to create a cluster diagram. Cluster analysis using an un-weighted pair-group method with arithmetic averages (UPGMA was used to group the varieties and the 30 aromatic rice varieties were grouped into 6 clusters where cluster I includes the maximum number of varieties (9. Cluster VI includes minimum number of varieties (2. This Study offered a rapid and reliable method for the estimation of variability between different varieties which could be utilized by the breeders for further improvement of the local aromatic rice varieties.

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

    Science.gov (United States)

    Hayakawa, Kazuichi

    2016-01-01

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

  14. Synthesis and anti-inflammatory properties of some aromatic and heterocyclic aromatic curcuminoids.

    Science.gov (United States)

    Khan, M Akram; El-Khatib, Riyad; Rainsford, K D; Whitehouse, M W

    2012-02-01

    A variety of novel aromatic and heterocyclic aromatic curcuminoids were synthesised, characterised and their anti-inflammatory activities (AIA) determined in vivo. Some of these compounds also were tested for inflammatory mediator production. The AIA of the main representatives of these compounds were assessed by oral administration to female Wistar rats using (a) acute carrageenan-induced paw oedema, (b) chronic adjuvant arthritis (therapeutic mode), and (c) anti-pyretic activity assessed in the yeast pyrexia. Gastric ulceration was determined in pre-inflamed rats. Natural curcumin showed modest aspirin-like anti-inflammatory activity which was enhanced when co-administered with the PGE(1) analogue misoprostol as a synergist. In contrast, four novel curcuminoids (RK-97, RK-103, RK-104 and RK-106) in which the bis-methoxy-phenyl group of curcumin was replaced with bis-dimethoxybutenolidyl-(ascorbate), bis-naphthyl, and bis-furanyl derivatives, respectively, had potent activity in the anti-arthritic assay with little gastric or systemic toxicity, compared with the vehicle-treated controls. Of the curcuminoids the furan RK-106 was the only compound to inhibit production of TNFα and IL-1β in a monocytic cell-line THP-1 in vitro. The inactivity of RK-106 on the production of PGE(2) may be related to its absence of gastrotoxicity. None of the curcuminoids exhibited anti-pyretic activity and this may also be related to its insensitivity to PGE(2). Thus, these novel curcuminoids, such as RK-106, may warrant the development of new low gastro-toxic anti-inflammatory agents with selective inhibitory activity of cytokine inflammatory mediators. PMID:22172598

  15. Parameters describing nonequilibrium transport of polycyclic aromatic hydrocarbons through contaminated soil columns: Estimability analysis, correlation, and optimization

    Science.gov (United States)

    Ngo, Viet V.; Michel, Julien; Gujisaite, Valérie; Latifi, Abderrazak; Simonnot, Marie-Odile

    2014-03-01

    The soil and groundwater at former industrial sites polluted by polycyclic aromatic hydrocarbons (PAHs) produce a very challenging environmental issue. The description of PAH transport by means of mathematical models is therefore needed for risk assessment and remediation strategies at these sites. Due to the complexity of release kinetics and transport behavior of the PAHs in the aged contaminated soils, their transport is usually evaluated at the laboratory scale. Transport parameters are then estimated from the experimental data via the inverse method. To better assess the uncertainty of optimized parameters, an estimability method was applied to firstly investigate the information content of experimental data and the possible correlations among parameters in the two-site sorption model. These works were based on the concentrations of three PAHs, Acenaphthene (ACE), Fluoranthene (FLA) and Pyrene (PYR), in the leaching solutions of the experiments under saturated and unsaturated flow conditions.

  16. Open Innovation

    OpenAIRE

    Аникина, К. Ю.; Таланкина, Н. Г.

    2006-01-01

    In the past 10 years, numerous interesting articles, book chapters, and books have been written on open innovation strategies in mainly large companies. While closed innovation models have resulted in important breakthrough innovations, many large companies have abandoned vertical integration strategies in recent years and have moved toward a combination of both closed and open innovation models that are used for reaching different sets of innovative goals. The definition of open innovation a...

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

    DEFF Research Database (Denmark)

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

    1996-01-01

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

  18. Exchangeable cations-mediated photodegradation of polycyclic aromatic hydrocarbons (PAHs) on smectite surface under visible light

    International Nuclear Information System (INIS)

    Graphical abstract: Roles of exchangeable cations in PAHs photodegradation on clay surafces under visible light. - Highlights: • Photolysis rate are strongly dependent on the type of cations on clay surface. • The strength of “cation–π” interactions governs the photodegradation rate of PAHs. • Several exchangeable cations could cause a shift in the absorption spectrum of PAHs. • Exchangeable cations influence the type and amount of reactive intermediates. - Abstract: Clay minerals saturated with different exchangeable cations are expected to play various roles in photodegradation of polycyclic aromatic hydrocarbons (PAHs) via direct and/or indirect pathways on clay surfaces. In the present study, anthracene and phenanthrene were selected as molecule probes to investigate the roles of exchangeable cations on their photodegradation under visible light irradiation. For five types of cation-modified smectite clays, the photodegradation rate of anthracene and phenanthrene follows the order: Fe3+ > Al3+ > Cu2+ >> Ca2+ > K+ > Na+, which is consistent with the binding energy of cation–π interactions between PAHs and exchangeable cations. The result suggests that PAHs photolysis rate depends on cation–π interactions on clay surfaces. Meanwhile, the deposition of anthracene at the Na+-smectite and K+-smectite surface favors solar light absorption, resulting in enhanced direct photodecomposition of PAHs. On the other hand, smectite clays saturated with Fe3+, Al3+, and Cu2+ are highly photoreactive and can act as potential catalysts giving rise to oxidative radicals such as O2−· , which initiate the transformation of PAHs. The present work provides valuable insights into understanding the transformation and fate of PAHs in the natural soil environment and sheds light on the development of technologies for contaminated land remediation

  19. Exchangeable cations-mediated photodegradation of polycyclic aromatic hydrocarbons (PAHs) on smectite surface under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Hanzhong, E-mail: jiahz@ms.xjb.ac.cn [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Li, Li [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Chen, Hongxia; Zhao, Yue [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); School of Geology and Mining Engineering, Xinjiang University, Urumqi 830046 (China); Li, Xiyou [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Wang, Chuanyi, E-mail: cywang@ms.xjb.ac.cn [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China)

    2015-04-28

    Graphical abstract: Roles of exchangeable cations in PAHs photodegradation on clay surafces under visible light. - Highlights: • Photolysis rate are strongly dependent on the type of cations on clay surface. • The strength of “cation–π” interactions governs the photodegradation rate of PAHs. • Several exchangeable cations could cause a shift in the absorption spectrum of PAHs. • Exchangeable cations influence the type and amount of reactive intermediates. - Abstract: Clay minerals saturated with different exchangeable cations are expected to play various roles in photodegradation of polycyclic aromatic hydrocarbons (PAHs) via direct and/or indirect pathways on clay surfaces. In the present study, anthracene and phenanthrene were selected as molecule probes to investigate the roles of exchangeable cations on their photodegradation under visible light irradiation. For five types of cation-modified smectite clays, the photodegradation rate of anthracene and phenanthrene follows the order: Fe{sup 3+} > Al{sup 3+} > Cu{sup 2+} >> Ca{sup 2+} > K{sup +} > Na{sup +}, which is consistent with the binding energy of cation–π interactions between PAHs and exchangeable cations. The result suggests that PAHs photolysis rate depends on cation–π interactions on clay surfaces. Meanwhile, the deposition of anthracene at the Na{sup +}-smectite and K{sup +}-smectite surface favors solar light absorption, resulting in enhanced direct photodecomposition of PAHs. On the other hand, smectite clays saturated with Fe{sup 3+}, Al{sup 3+}, and Cu{sup 2+} are highly photoreactive and can act as potential catalysts giving rise to oxidative radicals such as O{sub 2}{sup −}· , which initiate the transformation of PAHs. The present work provides valuable insights into understanding the transformation and fate of PAHs in the natural soil environment and sheds light on the development of technologies for contaminated land remediation.

  20. A new through-tubing oil-saturation measurement system

    International Nuclear Information System (INIS)

    This paper reports on carbon-oxygen logging which is used primarily to estimate oil saturation in cased-hole conditions when the formation water is fresh or unknown. The drawbacks of current techniques are: slow logging speed, large tool diameter, and excessive sensitivity to borehole fluid composition. A new, slim, neutron-induced gamma ray spectroscopy logging system has been developed to overcome some of these limitations. The new logging service is called the Reservoir Saturation (RST) Tool. Initial field tests are being carried out in the Middle East. The RST tool uses multiple detectors to separate the signal contributions from the borehole and the formation. Therefore, even when the borehole fluid composition is unknown, oil saturation can be determined in addition to the borehole oil fraction. This presents the possibility of logging flowing wells, which ensures that reinvasion and crossflow will not affect the results, and eliminates the costs of well preparation

  1. Mutual boosting of the saturation scales in colliding nuclei

    Science.gov (United States)

    Kopeliovich, B. Z.; Pirner, H. J.; Potashnikova, I. K.; Schmidt, Iván

    2011-03-01

    Saturation of small-x gluons in a nucleus, which has the form of transverse momentum broadening of projectile gluons in pA collisions in the nuclear rest frame, leads to a modification of the parton distribution functions in the beam compared with pp collisions. The DGLAP driven gluon distribution turns out to be suppressed at large x, but significantly enhanced at x ≪ 1. This is a high twist effect. In the case of nucleus-nucleus collisions all participating nucleons on both sides get enriched in gluon density at small x, which leads to a further boosting of the saturation scale. We derive reciprocity equations for the saturation scales corresponding to a collision of two nuclei. The solution of these equations for central collisions of two heavy nuclei demonstrate a significant, up to several times, enhancement of QsA2, in AA compared with pA collisions.

  2. Mutual boosting of the saturation scales in colliding nuclei

    CERN Document Server

    Kopeliovich, B Z; Potashnikova, I K; Schmidt, Ivan

    2010-01-01

    Saturation of small-x gluons in a nucleus, which has the form of transverse momentum broadening of projectile gluons in pA collisions in the nuclear rest frame, leads to a modification of the parton distribution functions in the beam compared with pp collisions. The DGLAP driven gluon distribution turns out to be suppressed at large x, but significantly enhanced at x<<1. This is a high twist effect. In the case of nucleus-nucleus collisions all participating nucleons on both sides get enriched in gluon density at small x, which leads to a further boosting of the saturation scale. We derive reciprocity equations for the saturation scales corresponding to a collision of two nuclei. The solution of these equations for central collisions of two heavy nuclei demonstrate a significant, up to several times, enhancement of Q_{sA}^2, in AA compared with pA collisions.

  3. Nonlinear acoustics of water-saturated marine sediments

    DEFF Research Database (Denmark)

    Jensen, Leif Bjørnø

    1976-01-01

    Interest in the acoustic qualities of water-saturated marine sediments has increased considerably during recent years. The use of sources of high-intensity sound in oil propsecting, in geophysical and geological studies of bottom and subbottom materials and profiles and recently in marine...... archaeology has emphasized the need of information about the nonlinear acoustic qualities of water-saturated marine sediments. While the acoustic experiments and theoretical investigations hitherto performed have concentrated on a determination of the linear acoustic qualities of water-saturated marine...... sediments, their parameters of nonlinear acoustics are still unexplored. The strong absorption, increasing about linearly with frequency, found in most marine sediments and the occurrence of velocity dispersion by some marine sediments restrict the number of nonlinear acoustic test methods traditionally...

  4. Gaussian beam diffraction in inhomogeneous and logarithmically saturable nonlinear media

    Science.gov (United States)

    Berczynski, Pawel

    2012-08-01

    The method of paraxial complex geometrical optics (PCGO) is presented, which describes Gaussian beam (GB) diffraction and self-focusing in smoothly inhomogeneous and nonlinear saturable media of cylindrical symmetry. PCGO reduces the problem of Gaussian beam diffraction in nonlinear and inhomogeneous media to the system of the first order ordinary differential equations for the complex curvature of the wave front and for GB amplitude, which can be readily solved both analytically and numerically. As a result, PCGO radically simplifies the description of Gaussian beam diffraction in inhomogeneous and nonlinear media as compared to the numerical and analytical methods of nonlinear optics. The power of PCGO method is presented on the example of Gaussian beam evolution in logarithmically saturable medium with either focusing and defocusing refractive profile. Besides, the influence of initial curvature of the wave front on GB evolution in nonlinear saturable medium is discussed in this paper.

  5. Symbolic Computation of Strongly Connected Components Using Saturation

    Science.gov (United States)

    Zhao, Yang; Ciardo, Gianfranco

    2010-01-01

    Finding strongly connected components (SCCs) in the state-space of discrete-state models is a critical task in formal verification of LTL and fair CTL properties, but the potentially huge number of reachable states and SCCs constitutes a formidable challenge. This paper is concerned with computing the sets of states in SCCs or terminal SCCs of asynchronous systems. Because of its advantages in many applications, we employ saturation on two previously proposed approaches: the Xie-Beerel algorithm and transitive closure. First, saturation speeds up state-space exploration when computing each SCC in the Xie-Beerel algorithm. Then, our main contribution is a novel algorithm to compute the transitive closure using saturation. Experimental results indicate that our improved algorithms achieve a clear speedup over previous algorithms in some cases. With the help of the new transitive closure computation algorithm, up to 10(exp 150) SCCs can be explored within a few seconds.

  6. Saturation scale fluctuations and multi-particle rapidity correlations

    CERN Document Server

    Bzdak, Adam

    2016-01-01

    We study the effect of intrinsic fluctuations of the proton saturation momentum scale on event-by-event rapidity distributions. Saturation scale fluctuations generate an asymmetry in the single particle rapidity distribution in each event resulting in genuine n-particle correlations having a component linear in the rapidities of the produced particles, $y_1\\cdots y_n$. We introduce a color domain model that naturally explains the centrality dependence of the two-particle rapidity correlations recently measured by ATLAS while constraining the probability distribution of saturation scale fluctuations in the proton. Predictions for n = 4, 6 and 8 particle correlations find that the four and eight-particle cumulant change sign at an intermediate multiplicity, a signature which could be tested experimentally.

  7. Prediction of saturated liquid enthalpy of refrigerant mixtures

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    New corresponding temperature and corresponding enthalpy of refrigerant mix- tures were defined. The relationship between saturated liquid corresponding en- thalpy and corresponding temperature of refrigerant mixtures accorded with that of pure components. The characteristic parameters of saturated liquid enthalpy dif- ference of refrigerant mixtures were calculated by three methods according to the different application conditions. The generalized equation of saturated liquid en- thalpy of refrigerant mixtures was presented. The calculated values were compared with the values in literature for five ternary and binary refrigerant mixtures, namely R404A, R407A, R407B, R32/R134a, and R410A. The overall average absolute devia- tion was less than 1.0%.

  8. Use of saturated sodium chloride solution as a tissue fixative

    Directory of Open Access Journals (Sweden)

    A. Al-Saraj

    2010-01-01

    Full Text Available The present study was carried out to examine the capability of saturated sodium chloride solution as a fixative agent instead of formalin which is regarded as a carcinogenic material. For this purpose 3 rabbits were used and their livers, kidneys and spleens were exposed and removed. Neutral buffered formalin solution, saturated sodium chloride solution and distilled water were used as fixatives for specimens obtained from the first, second and third rabbits respectively. Routine histological technique was performed to prepare a stained histological sections for light microscopic examination. The result showed that the tissue sections which were obtained by using sodium chloride have the same histological features and without any artifacts when they compared with the results obtained using formalin fixation method. We conclude that the saturated sodium chloride solution can be used as a fixative agent in some circumstances when no any fixative agent is available.

  9. Dynamic Tensile Strength of Coal under Dry and Saturated Conditions

    Science.gov (United States)

    Zhao, Yixin; Liu, Shimin; Jiang, Yaodong; Wang, Kai; Huang, Yaqiong

    2016-05-01

    The tensile failure characterization of dry and saturated coals under different impact loading conditions was experimentally investigated using a Split Hopkinson pressure bar. Indirect dynamic Brazilian disc tension tests for coals were carried out. The indirect tensile strengths for different bedding angles under different impact velocities, strain rates and loading rates are analyzed and discussed. A high-speed high-resolution digital camera was employed to capture and record the dynamic failure process of coal specimens. Based on the experimental results, it was found that the saturated specimens have stronger loading rate dependence than the dry specimens. The bedding angle has a smaller effect on the dynamic indirect tensile strength compared to the impact velocity. Both shear and tensile failures were observed in the tested coal specimens. Saturated coal specimens have higher indirect tensile strength than dry ones.

  10. Saturation dependence of the streaming potential during drainage and imbibition

    Science.gov (United States)

    Vinogradov, J.; Leinov, E.; Jackson, M.

    2012-12-01

    The rock pore space in many subsurface settings is saturated with water and one or more immiscible fluid phases; examples include NAPLs in contaminated aquifers, supercritical CO2 during sequestration in deep saline aquifers, the vadose zone, and hydrocarbon reservoirs. To interpret spontaneous potential measurements for groundwater flow and hydraulic properties in these settings requires an understanding of the saturation dependence of the streaming potential. Vinogradov and Jackson [2011] recently reported measurements of the streaming potential during drainage and, for the first time, imbibition in sandstone plugs saturated with water and either undecane or nitrogen. However, they reported effective values of the streaming potential coupling coefficient (C) at partial saturation (Sw), because Sw in the plugs was not uniform during drainage or imbibition. The aim of this study is to determine the true value of C as a function of Sw. We use a three-step approach in which hydraulic and electrical parameters are determined using numerical simulation and either Nelder-Mead simplex unconstrained optimisation or Active-set constrained optimisation algorithm. In the first step, we determine the saturation dependence of the relative permeability and capillary pressure, assuming these are simple exponential functions of Sw (Corey-type) and using an objective function which is a weighted average of the measured (i) pressure drop across the plug, (ii) liquid rate flowing out of the plug, and (iii) fraction of water flowing out of the plug. In the second, we determine the saturation dependence of the electrical conductivity, using the measured conductivity of the plug as the objective function. In the final step, we determine the saturation dependence of the streaming potential, using the measured streaming potential across the plug as the objective function. We obtain a good match between simulated and measured values of C, and find that it (i) exhibits hysteresis, (ii) can

  11. Premature saturation in backpropagation networks: Mechanism and necessary conditions

    International Nuclear Information System (INIS)

    The mechanism that gives rise to the phenomenon of premature saturation of the output units of feedforward multilayer neural networks during training with the standard backpropagation algorithm is described. The entire process of premature saturation is characterized by three distinct stages and it is concluded that the momentum term plays the leading role in the occurrence of the phenomenon. The necessary conditions for the occurrence of premature saturation are presented and a new method is proposed, based on these conditions, that eliminates the occurrence of the phenomenon. Validity of the conditions and the proposed method are illustrated through simulation results. Three case studies are presented. The first two came from a training session for classification of three component failures in a nuclear power plant. The last case, comes from a training session for classification of welded fuel elements

  12. On the number of $K_4$-saturating edges

    OpenAIRE

    Balogh, József; Liu, Hong

    2013-01-01

    Let $G$ be a $K_4$-free graph, an edge in its complement is a $K_4$-\\emph{saturating} edge if the addition of this edge to $G$ creates a copy of $K_4$. Erd\\H{o}s and Tuza conjectured that for any $n$-vertex $K_4$-free graph $G$ with $\\lfloor n^2/4\\rfloor+1$ edges, one can find at least $(1+o(1))\\frac{n^2}{16}$ $K_4$-saturating edges. We construct a graph with only $\\frac{2n^2}{33}$ $K_4$-saturating edges. Furthermore, we prove that it is best possible, i.e., one can always find at least $(1+o...

  13. Multilayer black phosphorus as broadband saturable absorber for pulsed lasers from 1 to 2.7 {\\mu}m wavelength

    CERN Document Server

    Kong, Lingchen; Xie, Guoqiang; Guo, Zhinan; Zhang, Han; Yuan, Peng; Qian, Liejia

    2015-01-01

    It attracts wide interest to seek universe saturable absorber covering wavelengths from near infrared to mid-infrared band. Multilayer black phosphorus, with variable direct bandgap (0.3-2 eV) depending on the layer number, becomes a good alternative as a universe saturable absorber for pulsed lasers. In this contribution, we first experimentally demonstrated broadband saturable absorption of multilayer black phosphorus from 1 {\\mu}m to 2.7 {\\mu}m wavelength. With the as-fabricated black phosphorus nanoflakes as saturable absorber, stable Q-switching operation of bulk lasers at 1.03 {\\mu}m, 1.93 {\\mu}m, 2.72 {\\mu}m were realized, respectively. In contrast with large-bandgap semiconducting transition metal dichalcogenides, such as MoS2, MoSe2, multilayer black phosphorus shows particular advantage at the long wavelength regime thanks to its narrow direct bandgap. This work will open promising optoelectronic applications of black phosphorus in mid-infrared spectral region and further demonstrate that BP may fil...

  14. Retention of polyphenyls and substituted polycyclic aromatic hydrocarbons in the system hydroxylated silica - n-hexane

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, Y.S.; Lanin, S.N. [Dept. of Chemistry, M.V. Lomonosov State Univ. of Moscow (Russian Federation); Al-Ahmed, A. [University of Aleppo (Syrian Arab Republic)

    1997-12-31

    The regularity of retention of unsubstituted and methyl-substituted polyphenyls and condensed polycyclic aromatic hydrocarbons in normal-phase (NP) HPLC with a non-polar mobile phase (n-hexane) on hydroxylated silica has been studied. It was shown that chromatographic retention of aromatic hydrocarbons depends not only on number of aromatic rings and methyl groups in a molecule, but also on a nature of the bond between the aromatic rings of polyphenyls and condensed polycyclic aromatic hydrocarbons. A structure - retention relationship has been proposed for description of the retention regularity of the aromatic hydrocarbons studied. (orig.)

  15. Impact of the Improved Patsari Biomass Stove on Urinary Polycyclic Aromatic Hydrocarbon Biomarkers and Carbon Monoxide Exposures in Rural Mexican Women

    OpenAIRE

    Riojas-Rodriguez, Horacio; Schilmann, Astrid; Marron-Mares, Adriana Teresa; Masera, Omar; Li, Zheng; Romanoff, Lovisa; Sjödin, Andreas; Rojas-Bracho, Leonora; Needham, Larry L.; Romieu, Isabelle

    2011-01-01

    Background: Cooking with biomass fuels on open fires results in exposure to health-damaging pollutants such as carbon monoxide (CO), polycyclic aromatic hydrocarbons (PAHs), and particulate matter. Objective: We compared CO exposures and urinary PAH biomarkers pre- and postintervention with an improved biomass stove, the Patsari stove. Methods: In a subsample of 63 women participating in a randomized controlled trial in central Mexico, we measured personal CO exposure for 8 hr during the day ...

  16. Sulfide Catalysts Supported on Porous Aromatic Frameworks for Naphthalene Hydroprocessing

    Directory of Open Access Journals (Sweden)

    Eduard Karakhanov

    2016-08-01

    Full Text Available This paper describes the first example of using porous aromatic frameworks as supports for sulfide catalysts for the hydrogenation of aromatic hydrocarbons. The synthesis of bimetallic Ni-W and Ni-Mo sulfides was performed by in situ decomposition of [(n-Bu4N]2[Ni(MeS42] (Me = W, Mo complexes, supported on mesoporous aromatic framework with a diamond-like structure. It is shown that the highest naphthalene conversions were achieved in the case of additional sulfidation with sulfur. After the reaction, catalysts were characterized by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. The activity of synthesized catalysts has been studied using naphthalene as a model substrate. The materials used in this study were substantially active in hydrogenation and slightly in hydrocracking of naphthalene.

  17. Aromatic rings in chemical and biological recognition: energetics and structures.

    Science.gov (United States)

    Salonen, Laura M; Ellermann, Manuel; Diederich, François

    2011-05-16

    This review describes a multidimensional treatment of molecular recognition phenomena involving aromatic rings in chemical and biological systems. It summarizes new results reported since the appearance of an earlier review in 2003 in host-guest chemistry, biological affinity assays and biostructural analysis, data base mining in the Cambridge Structural Database (CSD) and the Protein Data Bank (PDB), and advanced computational studies. Topics addressed are arene-arene, perfluoroarene-arene, S⋅⋅⋅aromatic, cation-π, and anion-π interactions, as well as hydrogen bonding to π systems. The generated knowledge benefits, in particular, structure-based hit-to-lead development and lead optimization both in the pharmaceutical and in the crop protection industry. It equally facilitates the development of new advanced materials and supramolecular systems, and should inspire further utilization of interactions with aromatic rings to control the stereochemical outcome of synthetic transformations. PMID:21538733

  18. Poly(N-arylenebenzimidazole)s via aromatic nucleophilic displacement

    Science.gov (United States)

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

    1996-01-01

    Novel poly(N-arylenebenzimidazole)s (PNABls) are prepared by the aromatic nucleophilic displacement reaction of novel di(hydroxyphenyl-N-arylene benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl-N-arylenebenzimidazole) monomers are synthesized by reacting phenyl-4-hydroxybenzoate with bis(2-aminoanilino)arylenes in diphenylsulfone. Moderate molecular weight PNABIs of new chemical structures were prepared that exhibit a favorable combination of physical and mechanical properties. The use of the novel di(hydroxyphenyI-N-arylenebenzimidazole)s permits a more economical and easier way to prepare PNABIs than previous routes.

  19. Poly(N-arylenbenzimidazoles) via aromatic nucleophilic displacement

    Science.gov (United States)

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

    1995-01-01

    Novel poly(N-arylenebenzimidazole)s (PNABIs) are prepared by the aromatic nucleophilic displacement reaction of novel di(hydroxyphenyl-N-arylene benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl N-arylenebenzimidazole) monomers are synthesized by reacting phenyl 4-hydroxybenzoate with bis(2-aminoanilino) arylenes in diphenylsulfone. Moderate molecular weight PNABIs of new chemical structures were prepared that exhibit a favorable combination of physical and mechanical properties. The use of the novel di(hydroxyphenyl N-arylenebenzimidazole)s permits a more economical and easier way to prepare PNABIs than previous routes.

  20. Does oligomerization in fused thiophene affect reactivity and aromaticity?

    Indian Academy of Sciences (India)

    Siddhartha Kr Purkayastha; Pradip Kr Bhattacharyya

    2016-02-01

    Reactivity and aromaticity of a few fused thiophene oligomers and their conformers are discussed in the light of density functional theory (DFT) and conceptual density functional theory. Reactivity parameters, such as hardness () and electrophilicity (), chemical potential () and energy of the HOMO (highest occupied molecular orbital) have been studied. Oligomerization raises the HOMO of the species, which in turn increases the reactivity of the oligomers. The absorption spectra of the species are analysed using TDDFT (time dependent density functional theory). The absorption peaks show red shift with increasing size of the oligomers. Aromaticity of the species is gauged by nucleus independent chemical shift (NICS). The out-of-plane component, (NICSzz) values advocate higher aromatic character at longer distance whereas, NICS supports the reverse.

  1. Theoretical Estimate of Hydride Affinities of Aromatic Carbonyl Compounds

    Institute of Scientific and Technical Information of China (English)

    AI Teng; ZHU Xiao-Qing; CHENG Jin-Pei

    2003-01-01

    @@ Aromatic carbonyl compounds are one type of the most important organic compounds, and the reductions ofthem by hydride agents such as LiAlH4 or NaBH4 are widely used in organic synthesis. The reactivity of carbonyl compounds generally increases in the following order: ketone < aldehyde, and amide < acid < ester < acid halide, which could be related to their hydride affinities (HA). In the previous paper, Robert[1] calculated the absolute HAof a series of small non-aromatic carbonyl compounds. In this paper, we use DFT method at B3LYP/6-311 + + G (2d, 2p)∥B3LYP/6-31 + G* level to estimate hydride affinities of five groups of aromatic carbonyl compounds. The detailed results are listed in Table 1.

  2. New Multi-1,2,3-Selenadiazole Aromatic Derivatives

    Directory of Open Access Journals (Sweden)

    S. Ratrout

    2005-09-01

    Full Text Available The aromatic polyketones 3a-d are versatile compounds for the synthesis of the multi-1,2,3-selenadiazole aromatic derivatives 1a-d. The preparation starts with the reaction between the multi-bromomethylene benzene derivatives 2a-d and 4-hydroxy- acetophenone to give compounds 3a-d which are transformed through the reaction with semicarbazide hydrochloride or ethyl hydrazine carboxylate into the corresponding semicarbazones derivatives 4a-d or hydrazones 5a-d. The reaction with selenium dioxide leads to regiospecific ring closure of semicarbazones or hydrazones to give the multi- 1,2,3-selenadiazole aromatic derivatives in high yield.

  3. Monitoring of fluorescent and nonfluorescent aromatics in waste water by rapid cyclohexane extraction and fluorometric detection: first measurements

    Science.gov (United States)

    Mittenzwey, Klaus-Henrik; Sinn, Gert

    1997-05-01

    Recently a new fluorescence method has been introduced applying two different signals: (1) the conventional fluorescence CF occurring at short path-lengths of the exciting radiation in the fluids, and (2) the multi-path saturation fluorescence MPSF originating at long path-lengths, which can be achieved by multi-path reflection cells, where the exciting radiation is fully absorbed by the fluid. This method considers both fluorescent as well as nonfluorescent substances. The ratio between CF and MPSF yields the total absorption. First experiments were performed to investigate this method for in-situ monitoring of aromatic substances in waste water. For this purpose samples of a waste water plant near Berlin were extracted with cyclohexane within 5 minutes in a first step yielding extracts with a waste water matrix. Then polycyclic aromatic substances were added directly to the cyclohexane extracts. The fluorescence CF and MPSF were measured at different excitation wavelengths in the UV part of the spectrum using a lab-standing experimental setup as well as a portable device. Synchronously, the conventional absorption of each sample was determined by an optical multi- channel analyzer. Regression analyses between the fluorescence ratio MPSF((lambda) 1)/MPSF((lambda) 2) and substance concentration yielded squared correlation coefficients r2 higher than these of conventional absorption spectrometry. Thus, the MPSF method is more accurate than the conventional absorption leading to lower detection limits. The MPSF method is obviously able to detect fluorescent and nonfluorescent aromatic hydrocarbons in cyclohexane extracts of waste water without further sample pre-treatment. Thus dangerous and harmless samples could be discriminated in field measurements.

  4. Force reflecting control with torque saturation compensation for telemanipulators

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, S. H.; Yun, J. S. [KAERI, Taejon (Korea, Republic of); Lee, S. J. [Chungnam National Univ., Taejon (Korea, Republic of)

    1999-10-01

    A force reflecting control method with torque saturation compensation is proposed for master slave force reflecting control systems which the slave manipulator has a torque saturation due to high reduction rate driver. The proposed force reflecting control method guarantees that the slave manipulator tracks the master position and the internal stability of the closed loop is satisfied. The proposed force reflecting control method enables the teleoperated manipulator treating heavy weight materials to be elaborately controlled maintaining force reflecting. The excellence of the proposed method is confirmed with a simulation.

  5. Force reflecting control with torque saturation compensation for telemanipulators

    International Nuclear Information System (INIS)

    A force reflecting control method with torque saturation compensation is proposed for master slave force reflecting control systems which the slave manipulator has a torque saturation due to high reduction rate driver. The proposed force reflecting control method guarantees that the slave manipulator tracks the master position and the internal stability of the closed loop is satisfied. The proposed force reflecting control method enables the teleoperated manipulator treating heavy weight materials to be elaborately controlled maintaining force reflecting. The excellence of the proposed method is confirmed with a simulation

  6. Bistability By Self-Reflection In A Saturable Absorber

    Science.gov (United States)

    Roso-Franco, Luis

    1987-01-01

    Propagation of laser light through a saturable absorber is theoretically studied. Computed steady state solutions of the Maxwell equations describing the unidimensional propagation of a plane monochromatic wave without introducing the slowly-varying envelope approximation are presented showing how saturation effects can influence the absorption of the field. At a certain range of refractive index and extintion coefficients, computed solutions display a very susprising behaviour, and a self-reflected wave appears inside the absorber. This can be useful for a new kind of biestable device, similar to a standard bistable cavity but with the back mirror self-induced by the light.

  7. Saturation in inclusive production beyond leading logarithm accuracy

    CERN Document Server

    Stasto, Anna M

    2016-01-01

    We review recent progress on the calculations on the inclusive forward hadron production within the saturation formalism. After introducing the concept of perturbative parton saturation and nonlinear evolution we discuss the formalism for the forward hadron production at high energy in the leading and next-to-leading order. Numerical results are presented and compared with the experimental data on forward hadron production in $dA$ and $pA$. We discuss the problem of the negativity of the NLO cross section at high transverse momenta, study its origin in detail and present possible improvements which include the corrected kinematics and the suitable choice of the rapidity cutoff.

  8. Wavelength dependence of gain saturation in GaAs lasers

    Energy Technology Data Exchange (ETDEWEB)

    Goebel, E.O.; Hildebrand, O.; Loehnert, K.

    1977-10-01

    The amplification of light in GaAs lasers is calculated self-consistently. It is shown that the wavelength dependence of the gain saturation is caused by the change of the chemical potential within the excited region due to the coupling of the carrier density with the photon density via the stimulated emission process. The effect of the wavelength dependent gain saturation on the stimulated emission spectra is calculated and compared with experimental results. Comparison of different recombination models indicates that a band-to-band transition without k-selection rules including tail states is the most appropriate description of the experimental data even for pure material.

  9. Contaminant-induced mechanical damping in partially saturated Berea sandstone

    Science.gov (United States)

    Brunner, W. M.; Spetzler, H. A.

    2002-08-01

    We have measured mechanical damping in partially saturated Berea sandstone that is strongly dependent on the presence of a small amount of oil. This effect is observed as a function of water saturation and average strain amplitude. These observations are presented as evidence of a damping mechanism previously observed and characterized in artificial cracks. We conclude that this damping effect is due to surface chemistry changes in the rock, and infer that seismic attenuation can be used to monitor small changes in pore fluid chemistry under certain conditions.

  10. Leaching from solidified waste forms under saturated and unsaturated conditions

    International Nuclear Information System (INIS)

    The leaching behavior of nitrate ion from a cement based waste form containing low-level radioactive waste was shown to be identical under saturated and unsaturated soil conditions. Only in soils containing less than 2 wt %water did the leach rate decrease. The observation of identical leach rates under saturated and unsaturated conditions is explained by diffusion through the waste form being the limiting step. Diffusion through the soil decreases in very dry soil and the limiting step changes. These laboratory tests were verified by measurements on similar, Portland cement based waste form in a field lysimeter

  11. The preliminary study on saturation problem of charge sensitive preamplifier

    International Nuclear Information System (INIS)

    The problem of a CSA (Charge Sensitive Preamplifier) saturation is an important problem .In the paper, starting from the working principle of a CSA, through the analysis of the detector output equivalent pulse sequence characteristics, combined with the actual physical process of a CSA, the upper limit value of CSA is conduced. And at the same time, the relationship between the count rates Ni and the time constant times i and the results of numerical analysis are given, as well as providing the theory basis for the design of a CSA considering the saturation limit. (authors)

  12. Stability study of saturated red polymer light-emitting diodes

    Institute of Scientific and Technical Information of China (English)

    XU Wei; PENG JunBiao; XU YunHua; WANG Jian; HUANG Zhe; NIU QiaoLi; CAO Yong

    2007-01-01

    Saturated red polymer light-emitting diodes have been fabricated with a single emitting polymer blend layer of poly[2-(2-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene](MEH-PPV)and poly[9,9-dioctylfluorene-co-4,7-di-2-thienyl-2,1,3-benzothiadiazole](PFO-DBT15).Saturated red emission with the Commission Internationale de I'Eclairage(CIE)coordinates of(0.67,0.33)was obtained.The device stability was investigated.The results showed that energy transfer occurred from MEH-PPV to PFO-DBT15,and MEH-PPV improved the hole injection and transportation.

  13. Exclusive vector meson production at HERA from QCD with saturation

    International Nuclear Information System (INIS)

    Following recent predictions that the geometric scaling properties of deep inelastic scattering data in inclusive γ*p collisions are expected also in exclusive diffractive processes, we investigate the diffractive production of vector mesons. Using analytic results in the framework of the Balitsky-Kovchegov (BK) equation at nonzero momentum transfer, we extend to the nonforward amplitude a QCD-inspired forward saturation model including charm, following the theoretical predictions for the momentum transfer dependence of the saturation scale. We obtain a good fit to the available HERA data and make predictions for deeply virtual Compton scattering measurements

  14. Porosity and size gradation of saturated gravel with percolated fines

    OpenAIRE

    Núñez González, Francisco; Martín Vide, Juan Pedro; Kleinhans Maarten, G.

    2016-01-01

    This is the accepted version of the following article: [Núñez-González, F., Martín-Vide, J. P., Kleinhans, M. G. (2016), Porosity and size gradation of saturated gravel with percolated fines. Sedimentology, 63: 1209–1232. doi: 10.1111/sed.12257], which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/sed.12257/abstract Fine particles may infiltrate through coarse alluvial beds and eventually saturate the subsurface pore space. It is essential to understand the...

  15. Evaluation of the Performance of Grouting Materials for Saturated Riprap

    OpenAIRE

    Daehyeon Kim; Sinkyu Jung; Kyungsub Cha

    2013-01-01

    In this study, four types of grout were developed to evaluate the effect of grouting of saturated riprap layers on ground water flow. The developed types of grout are divided into a quick-setting type and a general-type, and also into high and low viscosities. A number of grout tests were performed in a model acrylic chamber, 0.4 m in diameter and 2.0 m in length, for visual observation of injection. To reproduce the field flow condition of the saturated riprap layers (approach flow), the gro...

  16. On guaranteed cost control of linear systems with input saturation

    Institute of Scientific and Technical Information of China (English)

    FU Min-yue

    2007-01-01

    This work studies the problem of control design for linear systems with input saturation. It is well known that integral quadratic constraints (IQC) can be used to describe input saturation and that the use of IQC in analysis can lead to less conservative performance bound and larger domain of attraction. In this work, it is shown that a class of commonly used IQCs may not help in control synthesis. That is, the use of these IQCs does not enlarge the guaranteed domain of performance for synthesis.

  17. Open hardware for open science

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    Inspired by the open source software movement, the Open Hardware Repository was created to enable hardware developers to share the results of their R&D activities. The recently published CERN Open Hardware Licence offers the legal framework to support this knowledge and technology exchange.   Two years ago, a group of electronics designers led by Javier Serrano, a CERN engineer, working in experimental physics laboratories created the Open Hardware Repository (OHR). This project was initiated in order to facilitate the exchange of hardware designs across the community in line with the ideals of “open science”. The main objectives include avoiding duplication of effort by sharing results across different teams that might be working on the same need. “For hardware developers, the advantages of open hardware are numerous. For example, it is a great learning tool for technologies some developers would not otherwise master, and it avoids unnecessary work if someone ha...

  18. Classification of Malaysia aromatic rice using multivariate statistical analysis

    International Nuclear Information System (INIS)

    Aromatic rice (Oryza sativa L.) is considered as the best quality premium rice. The varieties are preferred by consumers because of its preference criteria such as shape, colour, distinctive aroma and flavour. The price of aromatic rice is higher than ordinary rice due to its special needed growth condition for instance specific climate and soil. Presently, the aromatic rice quality is identified by using its key elements and isotopic variables. The rice can also be classified via Gas Chromatography Mass Spectrometry (GC-MS) or human sensory panels. However, the uses of human sensory panels have significant drawbacks such as lengthy training time, and prone to fatigue as the number of sample increased and inconsistent. The GC–MS analysis techniques on the other hand, require detailed procedures, lengthy analysis and quite costly. This paper presents the application of in-house developed Electronic Nose (e-nose) to classify new aromatic rice varieties. The e-nose is used to classify the variety of aromatic rice based on the samples odour. The samples were taken from the variety of rice. The instrument utilizes multivariate statistical data analysis, including Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) and K-Nearest Neighbours (KNN) to classify the unknown rice samples. The Leave-One-Out (LOO) validation approach is applied to evaluate the ability of KNN to perform recognition and classification of the unspecified samples. The visual observation of the PCA and LDA plots of the rice proves that the instrument was able to separate the samples into different clusters accordingly. The results of LDA and KNN with low misclassification error support the above findings and we may conclude that the e-nose is successfully applied to the classification of the aromatic rice varieties

  19. Classification of Malaysia aromatic rice using multivariate statistical analysis

    Science.gov (United States)

    Abdullah, A. H.; Adom, A. H.; Shakaff, A. Y. Md; Masnan, M. J.; Zakaria, A.; Rahim, N. A.; Omar, O.

    2015-05-01

    Aromatic rice (Oryza sativa L.) is considered as the best quality premium rice. The varieties are preferred by consumers because of its preference criteria such as shape, colour, distinctive aroma and flavour. The price of aromatic rice is higher than ordinary rice due to its special needed growth condition for instance specific climate and soil. Presently, the aromatic rice quality is identified by using its key elements and isotopic variables. The rice can also be classified via Gas Chromatography Mass Spectrometry (GC-MS) or human sensory panels. However, the uses of human sensory panels have significant drawbacks such as lengthy training time, and prone to fatigue as the number of sample increased and inconsistent. The GC-MS analysis techniques on the other hand, require detailed procedures, lengthy analysis and quite costly. This paper presents the application of in-house developed Electronic Nose (e-nose) to classify new aromatic rice varieties. The e-nose is used to classify the variety of aromatic rice based on the samples odour. The samples were taken from the variety of rice. The instrument utilizes multivariate statistical data analysis, including Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) and K-Nearest Neighbours (KNN) to classify the unknown rice samples. The Leave-One-Out (LOO) validation approach is applied to evaluate the ability of KNN to perform recognition and classification of the unspecified samples. The visual observation of the PCA and LDA plots of the rice proves that the instrument was able to separate the samples into different clusters accordingly. The results of LDA and KNN with low misclassification error support the above findings and we may conclude that the e-nose is successfully applied to the classification of the aromatic rice varieties.

  20. Classification of Malaysia aromatic rice using multivariate statistical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, A. H.; Adom, A. H.; Shakaff, A. Y. Md; Masnan, M. J.; Zakaria, A.; Rahim, N. A. [School of Mechatronic Engineering, Universiti Malaysia Perlis, Kampus Pauh Putra, 02600 Arau, Perlis (Malaysia); Omar, O. [Malaysian Agriculture Research and Development Institute (MARDI), Persiaran MARDI-UPM, 43400 Serdang, Selangor (Malaysia)

    2015-05-15

    Aromatic rice (Oryza sativa L.) is considered as the best quality premium rice. The varieties are preferred by consumers because of its preference criteria such as shape, colour, distinctive aroma and flavour. The price of aromatic rice is higher than ordinary rice due to its special needed growth condition for instance specific climate and soil. Presently, the aromatic rice quality is identified by using its key elements and isotopic variables. The rice can also be classified via Gas Chromatography Mass Spectrometry (GC-MS) or human sensory panels. However, the uses of human sensory panels have significant drawbacks such as lengthy training time, and prone to fatigue as the number of sample increased and inconsistent. The GC–MS analysis techniques on the other hand, require detailed procedures, lengthy analysis and quite costly. This paper presents the application of in-house developed Electronic Nose (e-nose) to classify new aromatic rice varieties. The e-nose is used to classify the variety of aromatic rice based on the samples odour. The samples were taken from the variety of rice. The instrument utilizes multivariate statistical data analysis, including Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) and K-Nearest Neighbours (KNN) to classify the unknown rice samples. The Leave-One-Out (LOO) validation approach is applied to evaluate the ability of KNN to perform recognition and classification of the unspecified samples. The visual observation of the PCA and LDA plots of the rice proves that the instrument was able to separate the samples into different clusters accordingly. The results of LDA and KNN with low misclassification error support the above findings and we may conclude that the e-nose is successfully applied to the classification of the aromatic rice varieties.

  1. Nickel-Catalyzed Aromatic C-H Functionalization.

    Science.gov (United States)

    Yamaguchi, Junichiro; Muto, Kei; Itami, Kenichiro

    2016-08-01

    Catalytic C-H functionalization using transition metals has received significant interest from organic chemists because it provides a new strategy to construct carbon-carbon bonds and carbon-heteroatom bonds in highly functionalized, complex molecules without pre-functionalization. Recently, inexpensive catalysts based on transition metals such as copper, iron, cobalt, and nickel have seen more use in the laboratory. This review describes recent progress in nickel-catalyzed aromatic C-H functionalization reactions classified by reaction types and reaction partners. Furthermore, some reaction mechanisms are described and cutting-edge syntheses of natural products and pharmaceuticals using nickel-catalyzed aromatic C-H functionalization are presented. PMID:27573407

  2. STUDY OF AROMATIC CONTENT OF DIFFERENT BRANDIES MADE IN ARMENIA

    OpenAIRE

    Sukoyan M. R.; Kazumyan K. N.; Gharibyan H. A.; Guguchkina T. I.; Troshin L. P.

    2014-01-01

    Brandy alcohols from the grades of Muscat Berkatu, Kakhet and mixes of white grades of grapes became objects of researches. The content of some aromatic components of wine alcohols was investigated using the device of a gas-liquid chromatography Clarus-400 (with the ardent and ionization detector, a capillary column, 60 m x 0,32 mm, Elite-WAX ETR, gas-carrier-helium). Muscat alcohol according to the general content of aromatic substances (919,35 mg / 100 ml a.a.) was different from the other ...

  3. Database of the Amazon aromatic plants and their essential oils

    OpenAIRE

    José Guilherme S. Maia; Eloísa Helena A. Andrade

    2009-01-01

    The aromatic flora of the Amazon has been inventoried for 30 years. In this sense, were made over 500 field trips to collect over 2500 plants and to obtain more than 2000 essential oils and aroma concentrates, all of them submitted to GC and GC-MS. This work led to the creation of a database for the aromatic plants of the Amazon, which catalogs general information about 1250 specimens. The database has allowed the publication of the chemical composition of the oils and aromas of more than 350...

  4. Low toxicity aromatic diamine curing agents for adhesives

    Energy Technology Data Exchange (ETDEWEB)

    Dorsey, G.F.

    1993-08-24

    Increasing severity of regulations for handling of hazardous materials has led to formulation of adhesives with considerably lowered toxicities for use at the Oak Ridge Y-12 Plant. Fundamental was the development of Asilamine aromatic diamines, a family of liquid aromatic diamines useful as substitutes for methylenedianiline (MDA), a widely used adhesives curing agent. The use of Asilamine has allowed us to continue operations without dealing with expensive measures for regulation of MDA as a carcinogen promulgated by the Occupational Safety and Health Administration (OSHA).

  5. Aroma transition from rosemary leaves during aromatization of olive oil

    Directory of Open Access Journals (Sweden)

    Mustafa Yılmazer

    2016-04-01

    Full Text Available The aroma profile of aromatized olive oil was determined in this study. The primary objective was to investigate the transition of major aroma compounds from rosemary and olive fruit during the kneading step of olive oil production by response surface methodology. For this purpose, temperature, time, and amount of rosemary leaves were determined as independent variables. The results indicated that temperature and time did not affect the transition of target compounds, but rosemary leaves addition had a strong influence on transition, especially for characteristic aroma compounds of this herb. Adequacies of developed models were found to be high enough to predict each aromatic component of interest.

  6. Synthesis and Characterization of Aliphatic-Aromatic Hyperbranched Polyesters

    Institute of Scientific and Technical Information of China (English)

    唐黎明; 张晓龙; 邱藤; 刘德山

    2002-01-01

    Hyperbranched polymers possess special architectures and have potential applications in various areas. In this study, two AB2 monomers, dipropyl 5-(hydroxyethoxy) isophthalate (I) and 5-hydroxyethoxyisophthaic acid (II), were prepared. By bulk polycondensation of each monomer, two aliphatic-aromatic hyperbranched polyesters were prepared and characterized by 1H-nuclear magnetic resonance (1H-NMR), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), and scanning electron microscopy (SEM). Compared with all-aromatic hyperbranched polyesters, the prepared polymers showed lower glass transition temperatures in connection with the moderate decrease in their decomposition temperatures.

  7. Development and Application of Heat-integrated Aromatics Fractionation Process

    Institute of Scientific and Technical Information of China (English)

    Yang Weisheng; Kong Dejin; Tan Yongzhong

    2009-01-01

    The PRO/Ⅱ process simulation software was applied to carry out simulated calculation of the aromatics frac-tionation unit and the heat integrated rectification process was proposed for the aromatics fractionation section of the 1.0 Mt/a toluene disproportionation unit at the Zhenhai Refining and Chemical Company. The optimized operating parameters were obtained through the energy utilization analysis, process simulation, heat exchanger calculations and comparisons of utility consumption. The operation of commercialized unit has revealed that the design parameters of each rectification column were consistent with the operation results, and the utility consumption was about 47% lower than the waditional heat integrated process.

  8. DAR Assisted Layer-by-Layer Assembly of Aromatic Compounds

    Institute of Scientific and Technical Information of China (English)

    姜思光; 陈晓东; 张莉; 刘鸣华

    2003-01-01

    A facile DAR (diphenylamine-4-diazonium-formaldehyde resin)assisted layer-by-layer (LbL) assembly of uitrathin organic film of aromatic compounds has been investigated. The muitilayer of pyrene or anthracene was fabricated through simple dipping of the glass slide into the mixed solution of DAR with the target compounds. In this method, DAR acted as an assistant compound to help the assembling of the aromatic compounds. Such a convenient deposition method not only reserves the advantages of the traditional LbL technique but also simplifies the technique and extends the effectiveness of LbL technique to small molecules without any charge.

  9. Aromatic herbs in Corsican blue tit nests: The 'Potpourri' hypothesis

    Science.gov (United States)

    Lambrechts, Marcel M.; Dos Santos, Anabelle

    2000-05-01

    This study reports that Corsican blue tit ( Parus caeruleus ogliastrae) nests contain between one to five aromatic herb species between the onset of egg laying till the chicks' finished growth 13 d after hatching. An herb removal experiment during the chick stage shows that blue tits bring fresh aromatic material 1-5 d after herb removal. Nests with a series of distinct odour classes easily perceived by humans have never been reported in birds. A new 'Potpourri' hypothesis is proposed that may explain the functional significance of this behaviour.

  10. Open Access

    Science.gov (United States)

    Suber, Peter

    2012-01-01

    The Internet lets us share perfect copies of our work with a worldwide audience at virtually no cost. We take advantage of this revolutionary opportunity when we make our work "open access": digital, online, free of charge, and free of most copyright and licensing restrictions. Open access is made possible by the Internet and copyright-holder…

  11. The generation of stationary π-electron rotations in chiral aromatic ring molecules possessing non-degenerate excited states.

    Science.gov (United States)

    Yamaki, Masahiro; Teranishi, Yoshiaki; Nakamura, Hiroki; Lin, Sheng Hsien; Fujimura, Yuichi

    2016-01-21

    The electron angular momentum is a fundamental quantity of high-symmetry aromatic ring molecules and finds many applications in chemistry such as molecular spectroscopy. The stationary angular momentum or unidirectional rotation of π electrons is generated by the excitation of a degenerated electronic excited state by a circularly-polarized photon. For low-symmetry aromatic ring molecules having non-degenerate states, such as chiral aromatic ring molecules, on the other hand, whether stationary angular momentum can be generated or not is uncertain and has not been clarified so far. We have found by both theoretical treatments and quantum optimal control (QOC) simulations that a stationary angular momentum can be generated even from a low-symmetry aromatic ring molecule. The generation mechanism can be explained in terms of the creation of a dressed-state, and the maximum angular momentum is generated by the dressed state with an equal contribution from the relevant two excited states in a simple three-electronic state model. The dressed state is formed by inducing selective nonresonant transitions between the ground and each excited state by two lasers with the same frequency but having different polarization directions. The selective excitation can be carried out by arranging each photon-polarization vector orthogonal to the electronic transition moment of the other transition. We have successfully analyzed the results of the QOC simulations of (P)-2,2'-biphenol of axial chirality in terms of the analytically determined optimal laser fields. The present findings may open up new types of chemical dynamics and spectroscopy by utilizing strong stationary ring currents and current-induced magnetic fields, which are created at a local site of large compounds such as biomolecules. PMID:26670839

  12. Anomalous length dependence of conductance of aromatic nanoribbons with amine anchoring groups

    KAUST Repository

    Bilić, Ante

    2012-09-06

    Two sets of aromatic nanoribbons, based around a common hexagonal scaffolding, with single and dual terminal amine groups have been considered as potential molecular wires in a junction formed by gold leads. Charge transport through the two-terminal device has been modeled using density functional theory (with and without self-interaction correction) and the nonequilibrium Green\\'s function method. The effects of wire length, multiple terminal contacts, and pathways across the junction have been investigated. For nanoribbons with the oligopyrene motif and conventional single amine terminal groups, an increase in the wire length causes an exponential drop in the conductance. In contrast, for the nanoribbons with the oligoperylene motif and dual amine anchoring groups the predicted conductance rises with the wire length over the whole range of investigated lengths. Only when the effects of self-interaction correction are taken into account, the conductance of the oligoperylene ribbons exhibits saturation for longer members of the series. The oligoperylene nanoribbons, with dual amine groups at both terminals, show the potential to fully harness the highly conjugated system of π molecular orbitals across the junction. © 2012 American Physical Society.

  13. Factors affecting spatial variation of polycyclic aromatic hydrocarbons in surface soils in North China Plain.

    Science.gov (United States)

    Wang, Xilong; Zuo, Qian; Duan, Yonghong; Liu, Wenxin; Cao, Jun; Tao, Shu

    2012-10-01

    The spatial variation in concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in surface soils in the North China Plain and the influential factors were examined in the present study. High concentrations of the sum of 16 PAHs (∑PAH(16) ) appeared in cities and their surrounding areas. Emissions and soil organic carbon (SOC) content significantly regulated spatial differentiation of PAH contamination in soils in the study area. Compared with emissions, concentrations of individual and total PAHs in soils were more closely controlled by the SOC content. Furthermore, concentrations of PAH species with lower molecular weight (e.g., two- or three-ring) in surface soils were more strongly correlated with the SOC content in comparison with those of higher molecular weight (e.g., five- or six-ring), mainly because of their higher saturated vapor pressure, thus higher mobility. The spatial variation of PAH species in soils in the North China Plain tended to be larger with increasing benzene ring numbers, and the difference in physicochemical properties of PAH species determined their distinct spatial distribution characteristics. The present study highlights the relative importance of emissions and SOC content in spatial variation of PAHs and the dependence of the spatial distribution characteristics of PAH species in surface soils on their physicochemical properties at a regional scale. Results of the present work are helpful for regional risk assessment of the contaminants tested. PMID:22847656

  14. Ultrafast recovery time and broadband saturable absorption properties of black phosphorus suspension

    International Nuclear Information System (INIS)

    As a new type of two-dimensional crystal material, black phosphorus (BP) exhibits excellent electronics and optical performance. Herein, we focus on carrier relaxation dynamics and nonlinear optical properties of BP suspension. Atomic force microscopy, transmission electron microscopy, and optical transmission spectrum are employed to characterize the structure and linear optical properties of the BP. Additionally, pump-probe experiments at wavelength of 1550 nm were carried out to study the carrier dynamics in BP suspension, and ultrafast recovery time was observed (τs = 24 ± 2 fs). Furthermore, we demonstrate the saturable absorption signals by open aperture Z-scan experiments at wavelengths of 1550 nm, 532 nm, and 680 nm. The results indicate that BP has broadband saturable absorption properties and the nonlinear absorption coefficients were determined to be β2 = −0.20 ± 0.08 × 10−3 cm/GW (532 nm), β2 = −0.12 ± 0.05 × 10−3 cm/GW (680 nm), and β2 = −0.15 ± 0.09 × 10−3 cm/GW (1550 nm)

  15. Ultrafast recovery time and broadband saturable absorption properties of black phosphorus suspension

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yingwei; Huang, Guanghui; Chen, Jiazhang; Xiao, Si, E-mail: sixiao@csu.edu.cn; He, Jun, E-mail: junhe@csu.edu.cn [Institute of Super-Microstructure and Ultrafast Process in Advanced Materials, School of Physics and Electronics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083 (China); Mu, Haoran; Bao, Qiaoliang [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123 (China); Lin, Shenghuang [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123 (China); Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Hong Kong (China)

    2015-08-31

    As a new type of two-dimensional crystal material, black phosphorus (BP) exhibits excellent electronics and optical performance. Herein, we focus on carrier relaxation dynamics and nonlinear optical properties of BP suspension. Atomic force microscopy, transmission electron microscopy, and optical transmission spectrum are employed to characterize the structure and linear optical properties of the BP. Additionally, pump-probe experiments at wavelength of 1550 nm were carried out to study the carrier dynamics in BP suspension, and ultrafast recovery time was observed (τ{sub s} = 24 ± 2 fs). Furthermore, we demonstrate the saturable absorption signals by open aperture Z-scan experiments at wavelengths of 1550 nm, 532 nm, and 680 nm. The results indicate that BP has broadband saturable absorption properties and the nonlinear absorption coefficients were determined to be β{sub 2} = −0.20 ± 0.08 × 10{sup −3 }cm/GW (532 nm), β{sub 2} = −0.12 ± 0.05 × 10{sup −3 }cm/GW (680 nm), and β{sub 2} = −0.15 ± 0.09 × 10{sup −3 }cm/GW (1550 nm)

  16. The physical understanding on dynamic readout/detection of super-resolution pits with nonlinear reverse saturation absorption thin films

    International Nuclear Information System (INIS)

    The physical mechanism and understanding behind dynamic readout/detection of super-resolution pits with a nonlinear reverse-saturation absorption active layer, such as an InSb active layer, is presented on the basis of experimental results of open-aperture z-scan measurements and pump–probe transient time response analysis. The super-resolution of an InSb active layer is a result of the formation of a sub-wavelength scatterer region at the center of the focused spot. The frequency response function also verifies that the cutoff frequency with an InSb active layer is clearly extended compared to when an InSb active layer is not used. The findings are useful for understanding the physical process of the far-field super-resolution effect with nonlinear reverse-saturation absorption characteristics. (paper)

  17. Imbibition of hydraulic fracturing fluids into partially saturated shale

    Science.gov (United States)

    Birdsell, Daniel T.; Rajaram, Harihar; Lackey, Greg

    2015-08-01

    Recent studies suggest that imbibition of hydraulic fracturing fluids into partially saturated shale is an important mechanism that restricts their migration, thus reducing the risk of groundwater contamination. We present computations of imbibition based on an exact semianalytical solution for spontaneous imbibition. These computations lead to quantitative estimates of an imbibition rate parameter (A) with units of LT-1/2 for shale, which is related to porous medium and fluid properties, and the initial water saturation. Our calculations suggest that significant fractions of injected fluid volumes (15-95%) can be imbibed in shale gas systems, whereas imbibition volumes in shale oil systems is much lower (3-27%). We present a nondimensionalization of A, which provides insights into the critical factors controlling imbibition, and facilitates the estimation of A based on readily measured porous medium and fluid properties. For a given set of medium and fluid properties, A varies by less than factors of ˜1.8 (gas nonwetting phase) and ˜3.4 (oil nonwetting phase) over the range of initial water saturations reported for the Marcellus shale (0.05-0.6). However, for higher initial water saturations, A decreases significantly. The intrinsic permeability of the shale and the viscosity of the fluids are the most important properties controlling the imbibition rate.

  18. Test of the rosetta pedotransfer function for saturated hydraulic conductivity

    NARCIS (Netherlands)

    Alvarez-Acosta, C.; Lascano, R.J.; Stroosnijder, L.

    2012-01-01

    Simulation models are tools that can be used to explore, for example, effects of cultural practices on soil erosion and irrigation on crop yield. However, often these models require many soil related input data of which the saturated hy- draulic conductivity (Ks) is one of the most important ones. T

  19. Double shock dynamics induced by the saturation of defocusing nonlinearities

    KAUST Repository

    Crosta, Matteo

    2012-01-01

    We show that the saturation of defocusing nonlinearities leads to qualitative changes in the onset of wave breaking, determining double shock formation whose regularization occurs in terms of antidark solitons. In a given material, the crossover between different regimes can be controlled by changing the input intensity. © 2012 Optical Society of America.

  20. A characterization of saturated fusion systems over abelian 2-groups

    DEFF Research Database (Denmark)

    Henke, Ellen

    2014-01-01

    Given a saturated fusion system FF over a 2-group S, we prove that S is abelian provided any element of S  is F-conjugate to an element of Z(S). This generalizes a Theorem of Camina–Herzog, leading to a significant simplification of its proof. More importantly, it follows that any 2-block B of a ...

  1. The experiment on the saturation polarization of Rb vapour

    Institute of Scientific and Technical Information of China (English)

    Huang Xiang-You; You Pei-Lin; Du Wei-Min

    2004-01-01

    @@ A cylindrical capacitor containing rubidium vapour is made. The capacitance of it at. different voltages is measured under a certain Rb vapour pressure. The experimental C-V curve shows that the saturation polarization of Rb vapour is easily observed. The experiment further supports the idea that the Rb atom has a large permanent electric dipole moment.

  2. Absorption recovery in strongly saturated quantum-well electroabsorption modulators

    DEFF Research Database (Denmark)

    Højfeldt, Sune; Romstad, F.; Mørk, Jesper

    2003-01-01

    We observe experimentally that a quantum-well electroabsorption modulator, when strongly saturated by a highly energetic optical pulse, may exhibit an absorption recovery time much longer than for excitation with a low-energy pulse. Using a comprehensive drift-diffusion. type model, we are able to...

  3. Nuclear determination of saturation profiles in core plugs

    International Nuclear Information System (INIS)

    A method to determine liquid saturations in core plugs during flooding is of importance when the relative permeability and capillary pressure function are to be determined. This part of the EFP-95 project uses transmission of γ-radiation to determine these saturations. In γ-transmission measurements, the electron density of the given substance is measured. This is an advantage as compared to methods that use electric conductivity, since neither oil nor gas conducts electricity. At the moment a single 137Cs-source is used, but a theoretical investigation of whether it is possible to determine three saturations, using two radioactive sources with different γ-energies, has been performed. Measurements were made on three core plugs. To make sure that the measurements could be reproduced, all the plugs had a point of reference, i.e. a mark so that it was possible to place the plug same way every time. Two computer programs for calculation of saturation and porosity and the experimental setup are listed. (EG)

  4. Asymmetric gain-saturated spectrum in fiber optical parametric amplifiers

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Rottwitt, Karsten; Galili, Michael;

    2012-01-01

    We demonstrate experimentally and numerically an unexpected spectral asymmetry in the saturated-gain spectrum of single-pump fiber optical parametric amplifiers. The interaction between higher-order four-wave mixing products and dispersive waves radiated as an effect of third-order dispersion...

  5. Total mortality by elevated transferrin saturation in patients with diabetes

    DEFF Research Database (Denmark)

    Ellervik, Christina; Andersen, Henrik Ullits; Tybjærg-Hansen, Anne; Frandsen, Merete Müermann; Birgens, Henrik; Nordestgaard, Børge G; Mandrup-Poulsen, Thomas

    2013-01-01

    It is not known to what extent iron overload predicts prognosis in patients with diabetes after diagnosis or whether iron overload is a risk factor independent of the HFE genotype. We investigated total and cause-specific mortality according to increased transferrin saturation (≥ 50 vs....

  6. Simple Predictive Models for Saturated Hydraulic Conductivity of Technosands

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Razzaghi, Fatemeh; Møldrup, Per;

    2012-01-01

    Accurate estimation of saturated hydraulic conductivity (Ks) of technosands (gravel-free, coarse sands with negligible organic matter content) is important for irrigation and drainage management of athletic fields and golf courses. In this study, we developed two simple models for predicting Ks...

  7. Hydrocarbon saturation determination using acoustic velocities obtained through casing

    Science.gov (United States)

    Moos, Daniel

    2010-03-09

    Compressional and shear velocities of earth formations are measured through casing. The determined compressional and shear velocities are used in a two component mixing model to provides improved quantitative values for the solid, the dry frame, and the pore compressibility. These are used in determination of hydrocarbon saturation.

  8. Atmospheric sugar alcohols: evaporation rates and saturation vapor pressures

    DEFF Research Database (Denmark)

    Bilde, Merete; Zardini, Alessandro Alessio; Hong, Juan;

    allowed to evaporate in a laminar flow reactor, and changes in particle size as function of evaporation time are determined using a scanning mobility particle sizer system. In this work saturation vapor pressures of sugar alcohols at several temperatures have been inferred from such measurements using...

  9. Dispersive surface waves along partially saturated porous media

    NARCIS (Netherlands)

    Chao, G.; Smeulders, D.M.J.; Van Dongen, M.E.H.

    2006-01-01

    Numerical results for the velocity and attenuation of surface wave modes in fully permeable liquid/partially saturated porous solid plane interfaces are reported in a broadband of frequencies (100 Hz–1 MHz). A modified Biot theory of poromechanics is implemented which takes into account the interact

  10. PARTON SATURATION, PRODUCTION, AND EQUILIBRATION IN HIGH ENERGY NUCLEAR COLLISIONS

    International Nuclear Information System (INIS)

    Deeply inelastic scattering of electrons off nuclei can determine whether parton distributions saturate at HERA energies. If so, this phenomenon will also tell us a great deal about how particles are produced, and whether they equilibrate, in high energy nuclear collisions

  11. Test of the Rosetta Pedotransfer Function for saturated hydraulic conductivity

    Science.gov (United States)

    Simulation models are tools that can be used to explore, for example, effects of cultural practices on soil erosion and irrigation on crop yield. However, often these models require many soil related input data of which the saturated hydraulic conductivity (Ks) is one of the most important ones. The...

  12. Facilitated transport of copper with hydroxyapatite nanoparticles in saturated sand

    Science.gov (United States)

    Saturated packed column experiments were conducted to investigate the facilitated transport of Cu with hydroxyapatite nanoparticles (nHAP) at different pore water velocities (0.22-2.2 cm min–1), solution pH (6.2-9.0), and fraction of Fe oxide coating on grain surfaces (', 0-0.36). The facilitated tr...

  13. Lipase-catalyzed transesterification to remove saturated monoacylglycerols from biodiesel

    Science.gov (United States)

    Saturated monoacylglycerols (SMG) are known to be present in fatty acid methyl esters (FAME) intended to be used as biodiesel. These SMG can strongly affect the properties of biofuels such as the cloud point, and they have been implicated in engine failure due to filter plugging. It is shown here th...

  14. Approximate physical burnout model for forced convection of saturated fluid

    International Nuclear Information System (INIS)

    Approximate physical burnout model for forced convection of saturated fluid is considered. Relationships for determining critical heat flux are presented. They correspond satisfactorily with experimental data. Experimental data on burnout in two-phase flow for various fluids including water and helium are presented

  15. Reduction of Aromatic and Heterocyclic Aromatic N-Hydroxylamines by Human Cytochrome P450 2S1

    OpenAIRE

    Kai WANG; Guengerich, F. Peter

    2013-01-01

    Many aromatic amines and heterocyclic aromatic amines (HAAs) are known carcinogens for animals and there is also strong evidence for some in human cancer. The activation of these compounds, including some arylamine drugs, involves N-hydroxylation, usually by cytochrome P450 enzymes (P450) in Family 1 (1A2, 1A1, and 1B1). We previously demonstrated that the bioactivation product of the anti-cancer agent 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203), an N-hydroxylamine, can be reduc...

  16. Heating of a fully saturated darcian half-space: Pressure generation, fluid expulsion, and phase change

    Science.gov (United States)

    Delaney, P.

    1984-01-01

    Analytical solutions are developed for the pressurization, expansion, and flow of one- and two-phase liquids during heating of fully saturated and hydraulically open Darcian half-spaces subjected to a step rise in temperature at its surface. For silicate materials, advective transfer is commonly unimportant in the liquid region; this is not always the case in the vapor region. Volume change is commonly more important than heat of vaporization in determining the position of the liquid-vapor interface, assuring that the temperatures cannot be determined independently of pressures. Pressure increases reach a maximum near the leading edge of the thermal front and penetrate well into the isothermal region of the body. Mass flux is insensitive to the hydraulic properties of the half-space. ?? 1984.

  17. Study on Aromatization of C6 Aliphatic Hydrocarbons on ZRP Zeolite Catalyst

    Institute of Scientific and Technical Information of China (English)

    Wang Yongjun; Xie Chaogang

    2004-01-01

    The performance of ZRP zeolite catalysts for aromatization of C6 aliphatic hydrocarbons was investigated in a pulsed microreactor. The influence of metal modified ZRP zeolites on aromatization reaction was also studied, coupled with comparison of aromatization tendencies of olefins, paraffins and paraffins with different degrees of chain branching. Test results had shown that the lower the silicon/aluminum ratio in the ZRP zeolite, the higher the aromatization reactivity of aliphatic hydrocarbons. Modification of ZRP zeolite by zinc and its zinc content had apparent impact on the yield and distribution of aromatics. The aromatization tendency of olefins was apparently better than paraffins, while the aromatization tendency of monomethyl paraffins was better than that of straight-chain paraffins with the exception of dimethyl paraffins, which had worse aromatization tendency because of their steric hindrance.

  18. BIODEGRADATION OF AROMATIC COMPOUNDS UNDER MIXED OXYGEN/DENITRIFYING CONDITIONS: A REVIEW

    Science.gov (United States)

    Bioremediation of aromatic hydrocarbons in groundwater and sediments is often limited by dissolved oxygen. Many aromatic hydrocarbons degrade very slowly or not at all under anaerobic conditions. Nitrate is a good alternative electron acceptor to oxygen, and denitrifying bacteria...

  19. Adsorption of polar, nonpolar, and substituted aromatics to colloidal graphene oxide nanoparticles

    NARCIS (Netherlands)

    Wang, Fang; Haftka, Joris J H; Sinnige, Theo L.; Hermens, Joop L M; Chen, Wei

    2014-01-01

    We conducted batch adsorption experiments to understand the adsorptive properties of colloidal graphene oxide nanoparticles (GONPs) for a range of environmentally relevant aromatics and substituted aromatics, including model nonpolar compounds (pyrene, phenanthrene, naphthalene, and 1,3-dichlorobenz

  20. Open Education and the Open Science Economy

    Science.gov (United States)

    Peters, Michael A.

    2009-01-01

    Openness as a complex code word for a variety of digital trends and movements has emerged as an alternative mode of "social production" based on the growing and overlapping complexities of open source, open access, open archiving, open publishing, and open science. This paper argues that the openness movement with its reinforcing structure of…