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Sample records for benzene experimental study

  1. Experimental study of removing benzene from indoor air by needle-matrix to plate streamer discharge

    International Nuclear Information System (INIS)

    The degradation of benzene by needle-matrix to plate streamer discharge was investigated at normal temperature and pressure in indoor air. The effects of benzene initial concentration, air speed, discharge power and relative humidity (RH) on benzene removal rate were systematically studied. Meanwhile, the benzene removal efficiencies by adding MnO2/SiO2-active carbon catalyst to the system were also studied. The results showed that the benzene removal rate increased with the rise of the air speed and discharge power, decreased with the rise of the benzene initial concentration, and firstly increased and then decreased with the rise of the of RH. Under the same experimental conditions, adding MnO2 catalyst to the system did not significantly improve the removal efficiency of benzene.

  2. Thermal decomposition of norbornane (bicyclo[2.2.1]heptane) dissolved in benzene. Experimental study and mechanism investigation

    CERN Document Server

    Herbinet, Olivier; Battin-Leclerc, Fr{é}d{é}rique; Fournet, Ren{é}; Marquaire, Paul-Marie

    2007-01-01

    The thermal decomposition of norbornane (dissolved in benzene) has been studied in a jet stirred reactor at temperatures between 873 and 973 K, at residence times ranging from 1 to 4 s and at atmospheric pressure, leading to conversions from 0.04 to 22.6%. 25 reaction products were identified and quantified by gas chromatography, amongst which the main ones are hydrogen, ethylene and 1,3-cyclopentadiene. A mechanism investigation of the thermal decomposition of the norbornane - benzene binary mixture has been performed. Reactions involved in the mechanism have been reviewed: unimolecular initiations 1 by C-C bond scission of norbornane, fate of the generated diradicals, reactions of transfer and propagation of norbornyl radicals, reactions of benzene and cross-coupling reactions.

  3. Viscosities and ultrasonic speeds of binary mixtures of benzene with triethylamine and tributylamine at different temperatures: An experimental and theoretical study

    Institute of Scientific and Technical Information of China (English)

    Anwar Ali; Firdosa Nabi; Dinesh Chand; Anil Kumar Nain; Nizamul Haque Ansari

    2009-01-01

    The viscosities, η, and ultrasonic speeds,u, of pure benzene, triethylamine, (TEA) tributylamine, (TBA), and those of their binary mixtures, with benzene as common component, covering the whole composition range have been measured at 278.15 K, 283.15 K, 288.15 K, 293.15 K, 298.15 K, 303.15 K, 308.15 K, 313.15 K, and 318.15 K. From the experimental data the deviations in viscosity, △η, deviations in Gibbs free energy, △G, deviations in ultrasonic speed, Au, deviations in entropies, △S*, and deviations in enthalpies, △H*, of activation of viscous flow have been determined. The sign and magnitude of these parameters were found to be sensitive towards interactions prevailing in the studied systems. Further, the excess molar volumes, VE, were calculated using data for the binary mixtures. Moreover, theoretical values of viscosities and ultrasonic speeds of the binary mixtures were calculated using different empirical relations and theories. The results were discussed in terms of average deviations (AD) in experimental and theoretical values.

  4. A Quantum Monte Carlo Study of mono(benzene)TM and bis(benzene)TM Systems

    CERN Document Server

    Bennett, M Chandler; Mitas, Lubos

    2016-01-01

    We present a study of mono(benzene)TM and bis(benzene)TM systems, where TM={Mo,W}. We calculate the binding energies by quantum Monte Carlo (QMC) approaches and compare the results with other methods and available experiments. The orbitals for the determinantal part of each trial wave function were generated from several types of DFT in order to optimize for fixed-node errors. We estimate and compare the size of the fixed-node errors for both the Mo and W systems with regard to the electron density and degree of localization in these systems. For the W systems we provide benchmarking results of the binding energies, given that experimental data is not available.

  5. 2H NMR study of dynamics of benzene-d6 interacting with humic and fulvic acids.

    Science.gov (United States)

    Eastman, Margaret A; Brothers, Lucinda A; Nanny, Mark A

    2011-05-01

    Samples of three humic acids and one fulvic acid with 1% loading of benzene-d(6) in sealed glass tubes have been studied with solid-state deuterium quadrupole-echo nuclear magnetic resonance spectroscopy. Calculated spectra combining three motional models, two isotropic models and a third more restricted small-angle wobble (SAW) motional model, are fit to the experimental spectra. One isotropic motion (ISO(v)) is assigned to vaporous benzene-d(6) due to the small line width, short T(1), and the loss of this component by about -25 °C when the temperature is lowered. The remaining two motional components, ISO(s) and SAW, are sorbed by the humic or fulvic acid. Benzene-d(6) slowly interacts with the humic substances, progressively filling SAW sites as ISO(s) motion diminishes. Both the sorption and increase in percentage of SAW motion are for the most part complete within 200 days but continue to a lesser extent over a period of a few years. For the SAW motion there are at least two and most likely a series of T(1) values, indicating more than one adsorption environment. Enthalpies of sorption, obtained from application of the van't Hoff equation to the percentages of the different motional models derived from a series of variable temperature spectra, are comparable in magnitude to the enthalpy of vaporization of benzene. In Leonardite humic acid, ΔH and ΔS for the ISO(s) to SAW transition change from positive to negative values with age, implying a transition in the driving force from an entropic effect associated with expansion and deformation in the molecular structure of the humic substance to accommodate benzene-d(6) to an enthalpic effect of strong benzene-d(6)-humic substance interactions. In contrast, at advanced ages, Suwannee River humic and fulvic acids have small positive or near zero ΔH and positive ΔS for the ISO(s) to SAW transition. PMID:21456559

  6. Experimental study and kinetic modeling of the thermal degradation of aromatic volatile organic compounds (benzene, toluene and xylene-para) in methane flames; Etude experimentale et modelisation cinetique de la degradation thermique des composes organiques volatils aromatiques benzenes, toluene et para-xylene dans des flammes de methane

    Energy Technology Data Exchange (ETDEWEB)

    Dupont, L.

    2001-02-01

    This study treats of the thermal degradation of a family of aromatic volatile organic compounds (VOCs) in laminar premixed methane flames at low pressure. The experimental influence of benzene, toluene and xylene-para on the structure of a reference methane flame has been studied. The molar fraction profiles of the stable and reactive, aliphatic, aromatic and cyclic species have been established by the coupling of the molecular beam sampling/mass spectroscopy technique with the gas chromatography/mass spectroscopy technique. Temperature profiles have been measured using a covered thermocouple. A detailed kinetic mechanism of oxidation of these compounds in flame conditions has been developed. Different available sub-mechanisms have been used as references: the GDF-Kin 1.0 model for the oxidation of methane and the models of Tan and Franck (1996) and of Lindstedt and Maurice (1996) in the case of benzene and toluene. In the case of para-xylene, a model has been developed because no mechanisms was available in the literature. These different mechanisms have been refined, completed or adjusted by comparing the experimental results with those obtained by kinetic modeling. The complete kinetic mechanism, comprising 156 chemical species involved in 1072 reactions allows to reproduce all the experimental observations in a satisfactory manner. The kinetic analysis of reactions velocity has permitted to determine oxidation kinetic schemes for benzene, toluene, xylene-para and for the cyclopentadienyl radical, main species at the origin of the rupture of the aromatic cycle. Reactions of recombination with the methyl radicals formed during methane oxidation, of the different aromatic or aliphatic radicals created during the oxidation of aromatics, play an important role and lead to the formation of several aromatic pollutants (ethyl-benzene for instance) or aliphatic pollutants (butadiene or penta-diene for instance) in flames. (J.S.)

  7. On the role of delocalization in benzene: Theoretical and experimental investigation of the effects of strained ring fusion

    Energy Technology Data Exchange (ETDEWEB)

    Faust, R. [Lawrence Berkeley Lab., CA (United States). Chemical Sciences Div.; California Univ., Berkeley, CA (United States). Dept. of Chemistry

    1993-04-01

    When an important compound`s discovery dates back as far as 1825, one would imagine that every facet of its chemical and physical properties has been illuminated in the meantime. Benzene, however, has not ceased to challenge the chemist`s notion of structure and bonding since its first isolation by Michael Faraday. This report is divided into the following six chapters: 1. Aromaticity -- Criteria, manifestations, structural limitations; 2. The role of delocalization in benzene; 3. The thermochemical properties of benzocyclobutadienologs; 4. Ab initio study of benzenes fused to four-membered rings; 5. Non-planar polycyclic aromatic hydrocarbons; and 6. Experimental details and input decks. 210 Refs.

  8. Molecular simulation study on Hofmeister cations and the aqueous solubility of benzene.

    Science.gov (United States)

    Ganguly, Pritam; Hajari, Timir; van der Vegt, Nico F A

    2014-05-22

    We study the ion-specific salting-out process of benzene in aqueous alkali chloride solutions using Kirkwood-Buff (KB) theory of solutions and molecular dynamics simulations with different empirical force field models for the ions and benzene. Despite inaccuracies in the force fields, the simulations indicate that the decrease of the Setchenow salting-out coefficient for the series NaCl > KCl > RbCl > CsCl is determined by direct benzene-cation correlations, with the larger cations showing weak interactions with benzene. Although ion-specific aqueous solubilities of benzene may be affected by indirect ion-ion, ion-water, and water-water correlations, too, these correlations are found to be unimportant, with little to no effect on the Setchenow salting-out coefficients of the various salts. We further considered LiCl, which is experimentally known to be a weaker salting-out agent than NaCl and KCl and, therefore, ranks at an unusual position within the Hofmeister cation series. The simulations indicate that hydrated Li(+) ions can take part of the benzene hydration shell while the other cations are repelled by it. This causes weaker Li(+) exclusion around the solute and a resulting, weaker salting-out propensity of LiCl compared to that of the other salts. Removing benzene-water and benzene-salt electrostatic interactions in the simulations does not affect this mechanism, which may therefore also explain the smaller effect of LiCl, as compared to that of NaCl or KCl, on aqueous solvation and hydrophobic interaction of nonpolar molecules. PMID:24792435

  9. Study of HKUST (Copper benzene-1,3,5-tricarboxylate, Cu-BTC MOF)-1 metal organic frameworks for CH4 adsorption: An experimental Investigation with GCMC (grand canonical Monte-carlo) simulation

    International Nuclear Information System (INIS)

    We have measured the methane uptakes on HKUST (Copper benzene-1,3,5-tricarboxylate, Cu-BTC MOF)-1 MOF (metal organic framework) for the temperatures ranging from 120 K to 300 K and pressures up to 10 bar. The experimentally measured HKUST-1 + CH4 isotherms data are compared with uptakes of various adsorbents and methane systems. We have also simulated the methane uptakes and its density distribution on HKUST-1 employing GCMC (grand canonical Monte-carlo) simulation and compare with experimental data. In this article, we also present an extensive study on characterization and property evaluation of HKUST-1 MOF for CH4 adsorption characteristics employing XRD (X-ray diffraction), SEM (scanning electron microscope) and TGA (thermo gravimetric analysis). Employing GCMC and the thermodynamic property fields of HKUST-1 + CH4 system, the isosteric heat of adsorption (Qst) is calculated and Qst is presented in a T-s (temperature-entropy) diagram. - Highlights: • Characterization of HKUST-1 MOFs by XRD, SEM, N2 adsorption and TGA. • Measurement of CH4 uptakes on HKUST-1 by volumetric methods. • GCMC simulation of methane uptakes and its density distribution on HKUST-1. • Isosteric heat of adsorption in a T-s (temperature-entropy) diagram

  10. A comprehensive study of benzene concentrations and emissions in Houston

    Science.gov (United States)

    Müller, Markus; Eichler, Philipp; Berk Knighton, W.; Estes, Mark; Crawford, James H.; Mikoviny, Tomas; Wisthaler, Armin

    2014-05-01

    The Houston Metropolitan Area (Greater Houston) has a population of over 6 million people, it ranks among the three fastest growing metropolises in the developed world and population growth scenarios predict it to reach megacity status in the coming two to four decades. Greater Houston is home to the largest petrochemical-manufacturing complex in the world with important consequences for the environment in the region. Direct and fugitive emissions of hydrocarbons adversely affect Houston's air quality which has been subject to intense studies over the past two decades. In 2013, NASA conducted the DISCOVER-AQ field campaign in support of developing a satellite-based capability to assess Houston's air quality in the future. Amongst other measurements, airborne, mobile ground-based and stationary ground-based measurements of benzene were carried out. Benzene is a carcinogenic air toxic with strict exposure regulations in the U.S. and in Europe. We have used the obtained comprehensive dataset to map benzene concentrations in the Houston metropolitan area, locate and identify point sources, compare industrial and traffic emissions and put them in relation to previous measurements and emission inventories. The obtained data will allow a better assessment of health risks associated with benzene exposure in a large metropolitan area that includes both traffic and industrial benzene sources. This work was funded by BMVIT / FFG-ALR in the frame of the Austrian Space Application Programme (ASAP 8, project 833451). PE was funded through the PIMMS ITN (EU-FP7, agreement number 287382). Additional resources were provided through NASA's Earth Venture program (EV-1) and the NASA Postdoctoral Program (NPP). We want to thank Scott Herndon and Aerodyne Research for their support.

  11. Experimental and theoretical studies of the structural and electronic properties of vanadium–benzene sandwich clusters and their anions: VnBzn0/− (n = 1–5) and VnBzn−10/− (n = 2–5)

    International Nuclear Information System (INIS)

    One end open VnBzn− (n = 1–5; Bz = benzene) and both ends open VnBzn−1− (n = 2–5) vanadium–benzene cluster anions were studied using anion photoelectron spectroscopy and density functional calculations. The smaller (n ≤ 3) VnBzn and VnBzn−1 clusters and corresponding anions were found to have structural isomers, whereas full-sandwiched VnBzn+1 clusters preferred to form multiple-decker sandwich structures. Several isomeric V2Bz2 structures were identified theoretically and the anion photoelectron spectra of V2Bz20/− were explained well by the coexistence of two isomeric structures: (1) a V2-core structure sandwiched between benzene molecules and (2) an alternating sandwich structure with the spin state strongly dependent on the structure. The adiabatic electron affinity of both VnBzn and VnBzn−1 was found to increase with the cluster size at larger sizes (n = 4 or 5) and approaches to that of VnBzn+1. The evolution of the structural and electronic properties of VnBzm and VnBzm− (m = n and n − 1) with size is discussed in comparison with VnBzn+1 and VnBzn+1−

  12. Electrochemical study of benzene on Pt of various surface structures in alkaline and acidic solutions

    OpenAIRE

    Montilla Jiménez, Francisco; Morallón Núñez, Emilia; Vázquez Picó, José Luis

    2002-01-01

    The electrochemical behaviour of benzene on platinum electrodes (polycrystalline and single-crystal electrodes) has been studied in acidic and alkaline solutions. In acid solutions the reduction of benzene to cyclohexane takes place in all the platinum surface structure employed, however it does not occur in alkaline media (0.1 M NaOH). In this case, the hydrogen adsorption/desorption processes displace the adsorbed benzene from the electrode surface. The oxidation of benzene is also af...

  13. Diffusive Motions in Benzene and Toluene Studied with Slow Neutrons

    International Nuclear Information System (INIS)

    The viscosity of benzene is described by the Arrhenius equation ή = const. exp (E/kBT), where E is the activation energy for viscous flow. The viscosity of toluene, however, follows this law only in the higher temperature region of its liquid range, i.e. above the Arrhenius temperature TA. In the whole normal liquid range the benzene molecule is supposed to be able to rotate many times about at least two symmetry axes between translational jumps. Davies and Matheson suggest that the onset of non-Arrhenius viscosity behaviour in toluene occurs at that temperature at which rotation about two axes becomes restricted, while rotation about the third remains free. Inelastic scattering experiments of slow neutrons have been performed on the two substances using a time-of-flight spectrometer for cold neutrons with an energy resolution of 12 %. The quasi-elastic scattering has been studied for small momentum transfer as a function of temperature. Diffusion coefficients have been determined assuming a Lorentzian cross-section. The temperature dependence of the diffusion coefficient for benzene follows an exponential law, but the coefficient is a few times larger than the macroscopic coefficient, showing that a large amount of rotational diffusion exists. For toluene there is a change in the temperature dependence of the coefficient at about TA. This is taken as an indication of a change in the number of degrees of rotational freedom of the toluene molecule around TA. The methyl group in toluene has a low barrier to rotation (≲500 cal/mole). Therefore the hindered rotation levels of the methyl group as well as molecular rotation will contribute significantly to the inelastic scattering spectrum which overlaps the quasi-elastic peak. Th e inelastic component is subtracted by extrapolation but the possible contribution of the CH3 rotation to the quasi-elastic peak itself is neglected. (author)

  14. On-line CO, CO2 emissions evaluation and (benzene, toluene, xylene) determination from experimental burn of tropical biomass.

    Science.gov (United States)

    Tawfiq, Mohammed F; Aroua, Mohamed Kheireddine; Sulaiman, Nik Meriam Nik

    2015-07-01

    Atmospheric pollution and global warming issues are increasingly becoming major environmental concerns. Fire is one of the significant sources of pollutant gases released into the atmosphere; and tropical biomass fires, which are of particular interest in this study, contribute greatly to the global budget of CO and CO2. This pioneer research simulates the natural biomass burning strategy in Malaysia using an experimental burning facility. The investigation was conducted on the emissions (CO2, CO, and Benzene, Toluene, Ethylbenzene, Xylenes (BTEX)) from ten tropical biomass species. The selected species represent the major tropical forests that are frequently subjected to dry forest fire incidents. An experimental burning facility equipped with an on-line gas analyzer was employed to determine the burning emissions. The major emission factors were found to vary among the species, and the specific results were as follows. The moisture content of a particular biomass greatly influenced its emission pattern. The smoke analysis results revealed the existence of BTEX, which were sampled from a combustion chamber by enrichment traps aided with a universal gas sampler. The BTEX were determined by organic solvent extraction followed by GC/MS quantification, the results of which suggested that the biomass burning emission factor contributed significant amounts of benzene, toluene, and m,p-xylene. The modified combustion efficiency (MCE) changed in response to changes in the sample moisture content. Therefore, this study concluded that the emission of some pollutants mainly depends on the burning phase and sample moisture content of the biomass. PMID:26141898

  15. Human hemoglobin structural and functional alterations and heme degradation upon interaction with benzene: A spectroscopic study

    Science.gov (United States)

    Hosseinzadeh, Reza; Moosavi-Movahedi, Ali Akbar

    2016-03-01

    Here, the effect of benzene on hemoglobin structure, stability and heme prosthetic group integrity was studied by different methods. These included UV-vis absorption spectrophotometry, normal and synchronous fluorescence techniques, and differential scanning calorimetry (DSC). Our results indicated that benzene has high hemolytic potential even at low concentrations. The UV-vis spectroscopic results demonstrated that benzene altered both the globin chain and the heme prosthetic group of hemoglobin increasing met- and deoxy-Hb, while decreasing oxy-Hb. However, with increasing benzene the concentration of all species decreased due to heme destruction. The spectrophotometric results show that benzene has a high potential for penetrating the hydrophobic pocket of hemoglobin. These results were consistent with the molecular docking simulation results of benzene-hHb. Aggregation and thermal denaturation studies show that the increased benzene concentration induced hemoglobin aggregation with a decrease in stability, which is consistent with the DSC results. Conventional fluorescence spectroscopy revealed that the heme degradation species were produced in the presence of benzene. The results of constant wavelength synchronous fluorescence spectroscopy (CWSFS) indicated that at least five heme-degraded species were produced. Together, our results indicated that benzene has adverse effects on hemoglobin structure and function, and heme degradation.

  16. Revisiting the glass transition and dynamics of supercooled benzene by calorimetric studies

    Science.gov (United States)

    Tu, Wenkang; Chen, Zeming; Li, Xiangqian; Gao, Yanqin; Liu, Riping; Wang, Li-Min

    2015-10-01

    The glass transition and dynamics of benzene are studied in binary mixtures of benzene with five glass forming liquids, which can be divided into three groups: (a) o-terphenyl and m-xylene, (b) N-butyl methacrylate, and (c) N,N-dimethylpropionamide and N,N-diethylformamide to represent the weak, moderate, and strong interactions with benzene. The enthalpies of mixing, ΔHmix, for the benzene mixtures are measured to show positive or negative signs, with which the validity of the extrapolations of the glass transition temperature Tg to the benzene-rich regions is examined. The extrapolations for the Tg data in the mixtures are found to converge around the point of 142 K, producing Tg of pure benzene. The fragility m of benzene is also evaluated by extrapolating the results of the mixtures, and a fragility m ˜ 80 is yielded. The obtained Tg and m values for benzene allow for the construction of the activation plot in the deeply supercooled region. The poor glass formability of benzene is found to result from the high melting point, which in turn leads to low viscosity in the supercooled liquid.

  17. Modeling Studies on the Transport of Benzene and H2S in CO2-Water Systems

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, L.; Spycher, N.; Xu, T.; Apps, J.; Kharaka, Y.; Birkholzer, J.T.

    2010-11-05

    selected as a key compound for inclusion into numerical simulations. Note that considering additional organic compounds and/or mixtures of such compounds in the simulations was beyond the scope of this study, because of the effort required to research, calculate, and validate the phase-partitioning data necessary for simulations. The injection of CO{sub 2} into a deep saline aquifer was simulated, followed by modeling the leaching of benzene by SCC and transport of benzene to an overlying aquifer along a hypothetical leakage pathway. One- and two-dimensional models were set up for this purpose. The target storage formation was assumed to initially contain about 10{sup -4} ppm benzene. Model results indicate that: (1) SCC efficiently extracts benzene from the storage formation. (2) Assuming equilibrium, the content of benzene in SCC is roportional to the concentration of benzene in the aqueous and solid phases. (3) Benzene may co-migrate with CO{sub 2} into overlying aquifers if a leakage pathway is present. Because the aqueous solubility of benzene in contact with CO{sub 2} is lower than the aqueous solubility of CO{sub 2}, benzene is actually enriched in the CO{sub 2} phase as the plume advances. (4) For the case studied here, the resulting aqueous benzene concentration in the overlying aquifer is on the same order of magnitude as the initial concentration in the storage formation. This generic modeling study illustrates, in a semi-quantitative manner, the possible mobilization of benzene by SCC. The extent to which the mobilization of this organic compound evolves temporally and spatially depends on a large number of controlling parameters and is largely site specific. Therefore, for more 'truly' predictive work, further sensitivity studies should be conducted, and further modeling should be integrated with site-specific laboratory and/or field experimental data. The co-injection of H{sub 2}S with CO{sub 2} into a deep saline aquifer was also simulated. In

  18. Progress of epidemiological and molecular epidemiological studies on benzene in China.

    Science.gov (United States)

    Li, Guilan; Yin, Songnian

    2006-09-01

    Benzene is an organic solvent that has been used in industry for about 100 years throughout the world. Since 1973, a series of toxicological and molecular epidemiological studies on benzene were conducted by researchers at the Chinese Academy of Preventive Medicine (CAPM) (1973-1986) and subsequently by a collaboration between the CAPM and the National Cancer Institute (NCI) in the United States that began in 1986, which was joined by investigators from the University of California at Berkeley, the University of North Carolina at Chapel Hill, and New York University. The findings demonstrated that the risk of leukemia and lymphoma among benzene-exposed workers was significantly increased, with elevated risks for leukemia present not only at higher exposure but also among workers exposed to under 10 ppm. Therefore, the benzene permissible level was decreased to 1.8 ppm (6 mg/m(3)) and benzene-induced leukemia is treated as an occupational cancer in China. The benzene permissible level is 1.0 in the United States and in several other developed countries and it has been suggested to be decreased to 0.5 ppm (ACGIH). A number of potential biomarkers are related to benzene exposure and poisoning. Some of these are benzene oxide-protein adducts, chromosome aberration of lymphocytes, and GPA mutations in erythrocytes, a decrease in B cell and CD4(-)T cell counts in peripheral blood, and altered expression of CXCL16, ZNF331, JUN, and PF4 in lymphocytes. Variation in multiple benzene metabolizing genes may be associated with risk of benzene hematotoxicity, including CYP2E1, MPO, NQO1, and GSTT1. PMID:17119257

  19. Preparation of theoretical scanning tunneling microscope images of adsorbed molecules: a theoretical study of benzene on the Cu(110) surface

    International Nuclear Information System (INIS)

    Full text: Since its development in 1982, the Scanning Tunneling Microscope (STM) has developed into a powerful tool for the study of surfaces and adsorbates. However, the utility of the technique can be further enhanced through the development of techniques for generating theoretical STM images. This is particularly true when studying molecules adsorbed on a substrate, as the results are often interpreted superficially due to an inadequate understanding of the orbital overlap probed in the experiment. A method of preparing theoretical scanning tunneling microscope (STM) images using comparatively inexpensive desktop computers and the commercially available CRYSTAL98 package is presented through a study of benzene adsorbed on the Cu(110) surface. Density Functional Theory (DFT) and Hartree-Fock (HF) methods are used to model clean Cu(110) slabs of various thicknesses and to simulate the adsorption of benzene onto these slabs. Eight possible orientations of benzene on the Cu(110) surface are proposed, and the optimum orientation according to the calculations is presented. Theoretical STM images of the Cu(110) surface and benzene adsorbed on the Cu(110) surface are compared with experimental STM images of the system from a published study. Significant differences are observed and are examined in detail

  20. Literature study and experimental investigations into the production of organic iodine compounds in alkene, alkanol as well as benzene-vapour/air mixtures with radioiodine in the radiation field

    International Nuclear Information System (INIS)

    It was assumed in these investigations that these compounds originated in the gas phase by irradiation - induced reactions with radioiodine. Benzene, alcohol (methanol, ethanol) and alkene (ethylene, propylene) vapour/air mixtures were radiolysed with iodine in a Co-60 gamma source. The parameters varied were the concentrations and the irradiation doses (2 E + 03 Gy - 6 E + 04 Gy). The gaseous reaction mixtures were analysed qualitatively and quantitatively by an ECD- and a MSD-detector for iodine compounds difficult to separate. (orig.)

  1. Competitive Nitration of Benzene-Fluorobenzene and Benzene-Toluene Mixtures: Orientation and Reactivity Studies Using HPLC

    Science.gov (United States)

    Blankespoor, Ronald L.; Hogendoorn, Stephanie; Pearson, Andrea

    2007-01-01

    The reactivity and orientation effects of a substituent are analyzed by using HPLC to determine the competitive nitration of the benzene-toluene and benzene-fluorobenzene mixtures. The results have shown that HPLC is an excellent instrumental method to use in analyzing these mixtures.

  2. Experimental research on benzene detection using ion mobility spectrometer with a laser ionization source

    Institute of Scientific and Technical Information of China (English)

    LIU Xian-yun; KONG Xiang-he; JI Ren-dong; ZHANG Shu-dong

    2006-01-01

    An ion mobility spectrometer equipped with a laser ionization source is used for the sensitive detection of benzene.Mobility spectra of the benzene are presented.We also discussed the mobility spectra at various concentrations and drift voltages.Detection limits are determined to be in the upper ppbv range.In the end,the advantages and possibilities of this technique are briefly discussed.

  3. DFT study of benzene and CO co-adsorption on PtCo(1 1 1)

    International Nuclear Information System (INIS)

    Co-adsorption of benzene and CO on PtCo(1 1 1) surface at low coverage is studied using density functional theory calculations. We investigated the PtCo FCT alloy surface with a uniform distribution. The most favorable site for CO is top on a Pt atom whereas for benzene is an HCP hollow site (formed by 2 Pt atoms and 1 Co atom). The co-adsorption energy is −1.62 eV. The calculations indicate a CO molecule with a ∼4° tilt angle with the normal to the surface. The most important bond is Pt-CCO, as revealed by overlap population analysis. A very small CO–benzene interaction is also detected. The vibrational frequencies of adsorbed benzene and CO were also computed.

  4. Does borazine-water behave like benzene-water? A matrix isolation infrared and ab initio study

    Science.gov (United States)

    Mishra, P.; Verma, K.; Bawari, D.; Viswanathan, K. S.

    2016-06-01

    Borazine is isoelectronic with benzene and is popularly referred to as inorganic benzene. The study of non-covalent interactions with borazine and comparison with its organic counterpart promises to show interesting similarities and differences. The motivation of the present study of the borazine-water interaction, for the first time, stems from such interesting possibilities. Hydrogen-bonded complexes of borazine and water were studied using matrix isolation infrared spectroscopy and quantum chemical calculations. Computations were performed at M06-2X and MP2 levels of theory using 6-311++G(d,p) and aug-cc-pVDZ basis sets. At both the levels of theory, the complex involving an N-H⋯O interaction, where the N-H of borazine serves as the proton donor to the oxygen of water was found to be the global minimum, in contrast to the benzene-water system, which showed an H-π interaction. The experimentally observed infrared spectra of the complexes corroborated well with our computations for the complex corresponding to the global minimum. In addition to the global minimum, our computations also located two local minima on the borazine-water potential energy surface. Of the two local minima, one corresponded to a structure where the water was the proton donor to the nitrogen of borazine, approaching the borazine ring from above the plane of the ring; a structure that resembled the global minimum in the benzene-water H-π complex. The second local minimum corresponded to an interaction of the oxygen of water with the boron of borazine, which can be termed as the boron bond. Clearly the borazine-water system presents a richer landscape than the benzene-water system.

  5. Retrospective benzene exposure assessment for a multi-center case-cohort study of benzene-exposed workers in China.

    Science.gov (United States)

    Portengen, Lützen; Linet, Martha S; Li, Gui-Lan; Lan, Qing; Dores, Graça M; Ji, Bu-Tian; Hayes, Richard B; Yin, Song-Nian; Rothman, Nathaniel; Vermeulen, Roel

    2016-05-01

    Quality of exposure assessment has been shown to be related to the ability to detect risk of lymphohematopoietic disorders in epidemiological investigations of benzene, especially at low levels of exposure. We set out to build a statistical model for reconstructing exposure levels for 2898 subjects from 501 factories that were part of a nested case-cohort study within the NCI-CAPM cohort of more than 110,000 workers. We used a hierarchical model to allow for clustering of measurements by factory, workshop, job, and date. To calibrate the model we used historical routine monitoring data. Measurements below the limit of detection were accommodated by constructing a censored data likelihood. Potential non-linear and industry-specific time-trends and predictor effects were incorporated using regression splines and random effects. A partial validation of predicted exposures in 2004/2005 was performed through comparison with full-shift measurements from an exposure survey in facilities that were still open. Median cumulative exposure to benzene at age 50 for subjects that ever held an exposed job (n=1175) was 509 mg/m(3) years. Direct comparison of model estimates with measured full-shift personal exposure in the 2004/2005 survey showed moderate correlation and a potential downward bias at low (<1 mg/m(3)) exposure estimates. The modeling framework enabled us to deal with the data complexities generally found in studies using historical exposure data in a comprehensive way and we therefore expect to be able to investigate effects at relatively low exposure levels. PMID:26264985

  6. Endocrine-mediated effects of two benzene related compounds, 1-chloro-4-(chloromethyl)benzene and 1,3-diethyl benzene, based on subacute oral toxicity studies using rats.

    Science.gov (United States)

    Yamasaki, Kanji; Ishii, Satoko; Kikuno, Tsukasa; Minobe, Yasushi

    2012-08-01

    The purpose of this study was to investigate the endocrine-mediated effects of the benzene-related compounds with reference to Organization for Economic Co-operation and Development (OECD) Test Guideline No. 407. Rats were orally gavaged with 0, 10, 50, and 250 mg/kg/day of 1-chloro-4-(chloromethyl)benzene, and 0, 25, 150, and 1000 mg/kg/day of 1,3-diethyl benzene for at least 28 days, beginning at 8 weeks of age. Thyroid dysfunction was observed in rats given the 1,3-diethyl benzene. Serum T4 values increased in all groups of male rats and in the 1000 mg/kg group of female rats, and TSH values also increased in the 1000 mg/kg groups of both sexes after 28 days' administration. Decreased T3 values were observed in the 1000 mg/kg group of female rats after 28 days' administration, and hormone values increased in the 1000 mg/kg groups of both sexes after the 14-day recovery period. In addition, thyroid weight increased in the 1000 mg/kg groups and thyroid follicular cell hyperplasia was detected in one male rat from the 1000 mg/kg group after 28 days' administration. Endocrine-mediated effects, including thyroid dysfunction were not observed in any groups of rats treated with 1-chloro-4-(chloromethyl)benzene. Our results indicated that endocrine-mediated effects such as thyroid dysfunction were associated with some benzene-related compounds. PMID:22643015

  7. Experimental studies

    International Nuclear Information System (INIS)

    Spectral fluence measurements in an adult phantom are reported. A NaI(Tl) probe was used in various locations within the phantom and pulse-height spectra were obtained for seven beam configurations and three generating potentials. Some typical spectra results are presented. A comparison of calculated dose to experimental measurements is presented

  8. An epidemiologic study of early biologic effects of benzene in Chinese workers

    Energy Technology Data Exchange (ETDEWEB)

    Rothman, N.; Hayes, R.B.; Dosemeci, M. [National Cancer Institute, Bethesda, MD (United States)] [and others

    1996-12-01

    Benzene is a recognized hepatotoxin and leukemogen, but its mechanisms of action in humans are still uncertain. To provide insight into these processes, we carried out a cross-sectional study of 44 healthy workers currently exposed to benzene (median 8-hr time-weighted average; 31 ppm), and unexposed controls in Shanghai, China. Here we provide an overview of the study results on peripheral blood cell levels and somatic cell mutation frequency measured by the glycophorin A (GPA) gene loss assay and report on peripheral cytokine levels. 41 refs., 5 tabs.

  9. Study of hydroxylation of benzene and toluene using a micro-DBD plasma reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sekiguchi, H; Ando, M; Kojima, H [Department of Chemical Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2005-06-07

    The hydroxylation behaviour of benzene and toluene were studied using a micro-plasma reactor, where an atmospheric non-thermal plasma was generated by a dielectric barrier discharge (DBD). The results indicated that oxidation products primarily consisted of phenol and C{sub 4}-compounds for benzene hydroxylation, whereas cresol, benzaldehyde, benzylalcohol and C{sub 4}-compounds were detected for toluene hydroxylation. By taking into consideration the reaction mechanism in the plasma reactor, these products were classified into (1) oxidation of the aromatic ring and functional group on the ring and (2) cleavage of the aromatic ring or dissociation of the functional group on the ring.

  10. Study of hydroxylation of benzene and toluene using a micro-DBD plasma reactor

    International Nuclear Information System (INIS)

    The hydroxylation behaviour of benzene and toluene were studied using a micro-plasma reactor, where an atmospheric non-thermal plasma was generated by a dielectric barrier discharge (DBD). The results indicated that oxidation products primarily consisted of phenol and C4-compounds for benzene hydroxylation, whereas cresol, benzaldehyde, benzylalcohol and C4-compounds were detected for toluene hydroxylation. By taking into consideration the reaction mechanism in the plasma reactor, these products were classified into (1) oxidation of the aromatic ring and functional group on the ring and (2) cleavage of the aromatic ring or dissociation of the functional group on the ring

  11. Advances in Study on Catalysts for Phenol Synthesis via Catalytic Hydroxylation of Benzene in China

    Institute of Scientific and Technical Information of China (English)

    Zheng Zhaohui

    2004-01-01

    Synthesis of phenol via direct hydroxylation of benzene as a typical reaction of atomic economy has attracted extensive attention worldwide and has also become an actively investigated domain in China. This article refers to the recent domestic advances in study on phenol synthesis via hydroxylation of benzene from the viewpoint of catalysts, and considers the TS-1/H2O2 and FeZSM-5/N2O catalytic systems to be promising ones with good prospects for commercialization along with some suggestions on future research work.

  12. Study on Testing the Composition of Indoor Air Pollution to Benzene Series by Laser Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    XUE Mei; HE Le-min; ZHONG Wei-gang; ZHAO Xin; LI Xiu-zhen

    2014-01-01

    This paper reports some experimental detecting results of pollutants in the atmosphere by means of laser mass spectrometry. For toluene as calibration gas, the calibration procedure was also given. Benzene, toluene and xylene were discovered in testing indoor atmosphere resulting from dope in the course of fitment. Meanwhile, it is noticeable that the concentration of various harmful elements is obviously decreasing as time goes on.

  13. [High resolution laser transient spectroscopic technology under two-stage light gas-gun loading condition and stability study of shocked benzene].

    Science.gov (United States)

    Zhao, Bei-Jing; Liu, Fu-Sheng; Wang, Wen-Peng; Zhang, Ning-Chao; Feng, Li-Peng; Zhang, Ming-Jian; Xue, Xue-Dong

    2013-10-01

    The present paper reports the high resolution transient Raman laser testing technology under two-stage light gas-gun loading experiment, and its application to studying the Raman spectroscopy of shocked benzene. In the experiments, the frequency shift of C-C stretching vibration (992 cm(-1)) and C-H stretching vibration peak (3 061 cm(-1)) in the low pressure section (less than 8 GPa) varies linearly with the pressure, and the results agree well with reported data in the literature. The structural changes in liquid benzene about 13 GPa were clarified firstly by the Raman spectral technique; the experimental results show that at a pressure of 9.7 GPa, the structural change of liquid benzene has taken place, not reported in the literature about 13 GPa. But the composition in the production is not clear. The measurement system provides an effective means to study the microstructure changes of transparent and translucent material under dynamic loading experiment. PMID:24409699

  14. A mechanistic study on the reaction pathways leading to benzene and naphthalene in cellulose vapor phase cracking

    International Nuclear Information System (INIS)

    The reaction pathways leading to aromatic hydrocarbons such as benzene and naphthalene in gas-phase reactions of multi-component mixtures derived from cellulose fast pyrolysis were studied both experimentally and numerically. A two-stage tubular reactor was used for evaluating the reaction kinetics of secondary vapor phase cracking of the nascent pyrolysates at temperature ranging from 400 to 900 °C, residence time from 0.2 to 4.3 s, and at 241 kPa. The products of alkyne and diene were identified from the primary pyrolysis of cellulose even at low temperature range 500–600 °C. These products include acetylene, propyne, propadiene, vinylacetylene, and cyclopentadiene. Experiments were also numerically validated by a detailed chemical kinetic model consisting of more than 8000 elementary step-like reactions with over 500 chemical species. Acceptable capabilities of the kinetic model in predicting concentration profiles of the products enabled us to assess reaction pathways leading to benzene and naphthalene via the alkyne and diene from primary pyrolysates of cellulose. C3 alkyne and diene are primary precursors of benzene at 650 °C, while combination of ethylene and vinylacetylene produces benzene dominantly at 850 °C. Cyclopentadiene is a prominent precursor of naphthalene. Combination of acetylene with propyne or allyl radical leads to the formation of cyclopentadiene. Furan and acrolein are likely important alkyne precursors in cellulose pyrolysis at low temperature, whereas dehydrogenations of olefins are major route to alkyne at high temperatures. - Highlights: • Analytical pyrolysis experiments provided data for kinetic modeling. • Detailed chemical kinetic model was used and evaluated. • Alkyne and diene were important intermediates for aromatic hydrocarbon formation. • Reaction pathways leading to aromatic hydrocarbons were proposed

  15. TDDFT-MD Study on Dynamics in Photoinduced Ring Opening of Benzene

    Science.gov (United States)

    Tateyama, Yoshitaka; Miyamoto, Yoshiyuki; Oyama, Norihisa; Ohno, Takahisa

    2004-03-01

    Coupled dynamics of ions and electrons in the excited states of molecular and solid benzene is investigated on the femtosecond scale by the efficient simulation scheme recently developed for the time-dependent density functional theory. Within the π arrow π excitations, any out-of-plane motion of ions is not induced in the molecular system basically. In the solid, however, we found that large swing of the C-H bonds and subsequent twist of the carbon ring takes place, leading to sp^3-like bonding of carbon ions. This swing-to-twist motion presents a plausible mechanism underlying the photoinduced ring opening in solid benzene experimentally observed under pressure. This research is partially supported by ACT-JST, and also by FSIS and Special Coordination Funds of Ministry of Education, Culture, Sports, Science and Technology of Japanese Government.

  16. Are there Efimov trimers in hexafluorobenzene rather than in benzene vapor itself?

    International Nuclear Information System (INIS)

    Is there a spectroscopic method to detect an Efimov state? Following our proposal of an Efimov state arising from three pseudo bosons (generalized Cooper pairs) in benzene, our spectroscopic studies have found no evidence of Efimov trimers (ET) in h6- or d6-benzene. However, hexafluoro-benzene has shown peaks that we attributed to ET and the pseudo bosons. The experimental evidence suggests that benzene pseudo bosons and subsequently ET are quite sensitive to the surroundings

  17. NMR studies of benzene mobility in microporous metal-organic framework MOF-5

    International Nuclear Information System (INIS)

    Microporous metal-organic frameworks (MOF) are crystalline coordination polymers with regular three dimensional pore networks. These pore networks enable adsorption and diffusion of guest molecules. Molecular Dynamics (MD) simulations show that benzene has a liquid-like mobility inside the pores of MOF-5. Nuclear Magnetic Resonance (NMR) methods allow experimental access to guest mobilities inside such pore networks. This report presents the results of pulsed field gradient NMR (PFG NMR) self-diffusion measurements of benzene adsorbed in MOF-5. In these experiments multi-exponential spin echo decays were observed, which are usually caused by different phases of self-diffusion. These different phases of benzene mobility were unexpected for diffusion of molecules inside an isotropic framework and have to originate in the host-guest and guest-guest interaction. By modern diffusion-relaxation correlation spectroscopy (DRCOSY) translational self-diffusion and microscopic relaxation behavior were correlated. Together with magic angle spinning (MAS) NMR spectroscopy these investigations reveal that the faster component of the diffusion coefficients can be assigned to diffusion inside the porous crystal structure of MOF-5.

  18. QSTR studies regarding the ECOSAR toxicity of benzene-carboxylic acid' esters to fathead minnow fish (Pimephales promelas).

    Science.gov (United States)

    Tarko, Laszlo; Putz, Mihai V; Ionascu, Cosmin; Putz, Ana-Maria

    2014-01-01

    The present work employs 152 benzene-carboxylic acid' esters having computed the toxicity within the range [2.251, 10.222] for fathead minnow fish (Pimephales promelas). Calibration set includes many pairs having very similar chemical structure, size, shape and hydrophilicity, but very different value of ECOSAR toxicity or vice versa. The QSTR study, which uses all esters as calibration set, emphasized a large percent (16.2%) of outliers. In this QSTR study most of the estimated values of toxicity for outliers are much lower than ECOSAR toxicity. The LogP and some aromaticity descriptors are predictors. The best QSTR for esters having low value (toxicity and the best QSTR for esters having high value (> 5.5) of ECOSAR toxicity are obtained when the number of outliers is very small. These QSTRs are different enough and highlight opposite influences of certain descriptors on toxicity. The results emphasize two possibilities: (a) the esters having low value of ECOSAR toxicity and the esters having high value of ECOSAR toxicity are included in two different classes from the point of view of structure-toxicity relationship and/or (b) many high values of ECOSAR toxicity are wrong. By comparison, a QSTR using experimental values of toxicity against rats for 37 benzene-carboxylic esters included in the same database gives good correlation experimental/computed values of toxicity, the number of outliers is null and the result of validation test is good. PMID:24724900

  19. 脉冲电晕法处理含苯废气实验研究%Experimental analysis of PCPP-removal of exhaust gas involving Benzene

    Institute of Scientific and Technical Information of China (English)

    翁棣; 张艳; 楼婷婷; 吕碧洪; 徐涛; 张文聪

    2011-01-01

    挥发性有机物(VOCs)的污染与控制技术日益受到重视.近年来发展起来的非平衡等离子体技术在治理VOCs方面已初步显示其独特的技术优势,现已成为废气治理研究领域中的前沿热点课题之一.等离子体法降解VOCs的机理较为复杂,研究不同线路对VOCs降解过程的影响意义重大.采用脉冲电晕放电等离子体技术,建立了混合电晕、有机电晕、空气电晕和分别电晕4种不同的实验方案,选取苯为代表物质进行实验研究,在初始浓度、停留时间和电源参数等一定的条件下,考察脉冲电压对苯去除率的影响.结果表明,电压为140 kV、混合电晕时苯的去除率达到82.73%,脉冲电晕技术处理低浓度有机废气效果较好.%More attentions are gradually paid to the pollution and treatment of VOCs. The current technologies for controlling VOCs have associated with some problems. Pulse corona induced plasma discharge process (PCPP) is regarded as a promising technology to control the pollutants. The mechanism with which plasma degrades VOCs is complicated, therefore studies on different connections as well as their influences on decomposing process are significant. PPCP is employed to degrade VOCs such as benzene. Four different connections are built, which are “mix together before corona discharge, corona discharge benzene sample only, corona discharge air only, both benzene sample and air are corona discharged before mix together.” On the basis of unchanged inlet concentration, resident time and parameter of electrical source, the removal efficiency of benzene is investigated at different voltages. Reaction mechanisms are discussed based on the removal efficiency at different connections. For optimal experimental conditions(applied voltage of 140kV, connection of “mix together before corona discharge”), the removal efficiency is equal to 82.73%.

  20. An expanded cohort study of cancer among benzene-exposed workers in China

    Energy Technology Data Exchange (ETDEWEB)

    Song-Nian Yin; Gui-Lan Li; Zhi-Nan Zhang [Chinese Academy of Preventive Medicine, Bejing (China)] [and others

    1996-12-01

    An expanded cohort study of 74,828 benzene-exposed and 35,805 unexposed workers were followed during 1972 to 1987, based on a previous study in 12 cities in China. A small increase was observed in total cancer mortality among benzene-exposed compared with unexposed Workers (relative risk [RR] = 1-2). Statistically significant excesses were noted for leukemia (RR = 2.3), malignant lymphoma (RR = 4.5), and lung cancer (RR = 1.4). When risks were evaluated by leukemia subtype, only acute myelogenous leukemia was significantly elevated (RR = 3.1), although nonsignificant excesses were also noted for chronic myelogenous leukemia (RR = 2.6) and acute lymphocytic leukemia (RR = 2.3). A significant excess was also found for aplastic anemia. 19 refs., 5 tabs.

  1. DFT study of electronic transfer properties of carboxyl and nitro substituted benzene

    International Nuclear Information System (INIS)

    The electronic and optical transfer properties of Benzene, Benzoic Acid (BA), Nitrobenzene (NB) and Para Nitro Benzoic Acid (PNBA) at ground and first excited state has been investigated by the Density functional theory (DFT)and Time Dependent Density Functional Theory (TDDFT) using SVWN functional/3-21G basis set respectively. Possible intra-molecular charge transfer and n to π* transitions in the ground and the first excitation states have been predicted by the molecular orbitals and the Natural Bond Orbital (NBO) analysis. The simulated absorption spectra have been generated and the result compared with existing experimental results

  2. Theoretical study on second-order nonlinear optical properties of unsymmetric bis (phenylethynyl) benzene series derivatives

    Institute of Scientific and Technical Information of China (English)

    FU, Wei; FENG, Ji-Kang; YU, Kun-Qian; REN, Ai-Min; CUI, Meng

    2000-01-01

    On the basis of Z1NDO methods, according to the sum-overstates (SOS) expression, the progran for the calculation of the second-order nonlinear optical susceptibilities βuk and βμ ofmolecules was devised, and the structures and nonlinear optical properties of unsymmetric bis (phenylethynyl) benzene series derivatives were studied. The influence of the molecular conjugated chain lengths, the donor and the acceptor on βμwas examined.

  3. Theoretical Study of the Benzene Cation%苯分子离子的理论研究

    Institute of Scientific and Technical Information of China (English)

    刘亚军; 邝平先; 黄明宝

    2001-01-01

    The Jahn-Teller distorted states, 2B2g and 2B1g of the benzene radical cation have been studied by using ab initio MPn and SDCI methods. The calculations indicate that 2B2g is the ground state of the benzene cation and that 2B1g is higher in energy than 2B2g and represents a saddle point. The calculated isotropic and anisotropic hyperfine coupling constants for the 2B2g state are in excellent agreement with those obtained from the ESR experiments. It is concluded that the benzene cation is in the 2B2g Jahn-Teller distorted state.

  4. Aggregation of deuterodichlormethane molecules with benzene molecules. Quantum-chemical calculations and spectroscopic studies

    International Nuclear Information System (INIS)

    C-D vibration band of deuterodichlormethane CD2Cl2 at its low concentration in benzene is slitted into components with frequency 2198 and 2193 cm-1 that is related to formation of weak benzene+deuterodichlormethane complexes. Quantum-chemical calculations confirm a formation of deuterodichlormethane+benzene dimer with participation of benzene's π -electron. Steric factors lead to a difference in orientation of one of deuterium atoms from the central orientation with respect to benzene ring. According to calculations the energy of deuterodichlormethane+benzene dimer is 1.2 kcal/mole. (author)

  5. Experimental density, viscosity, interfacial tension and water solubility of ethyl benzene-α-methyl benzyl alcohol–water system

    International Nuclear Information System (INIS)

    Highlights: • Properties were measured for MBA (methyl benzyl alcohol)-EB (ethyl benzene)-water. • MBA concentration was found to influence all the properties strongly. • The water solubility, density, and viscosity increased at high MBA concentration. • The interfacial tension decreased sharply at high MBA concentration. • MBA dictates the phase separation and mass transfer of the ternary system. -- Abstract: Density, viscosity, interfacial tension, and water solubility were measured for the (α-methyl benzyl alcohol (MBA) + Ethyl benzene (EB)) system at different concentrations of MBA in contact with water and sodium hydroxide solution (0.01 mol · kg−1) as aqueous phases. The properties were measured to identify the component which plays a governing role in changing the physical properties relevant to mass transfer and phase separation of the ternary system. The concentration of MBA was found to be the major factor influencing all the properties. The water solubility, the density, and the viscosity increased notably at higher concentrations of MBA; while, the interfacial tension decreased strongly. The use of 0.01 mol · kg−1 NaOH as an aqueous phase resulted in a decrease of the interfacial tension and a minor decrease in the water solubility. The density data were correlated using a quadratic mixing rule to describe the influence of concentration at any temperature. The viscosity data are correlated using the Nissan and Grunberg and Katti-Chaudhri equations. The Szyzkowski’s equation was used to correlate the interfacial tension data. The water solubility data were described using an exponential relationship. All the correlations described the experimental physical property data adequately

  6. Phase II metabolism of benzene.

    OpenAIRE

    Schrenk, D.; Orzechowski, A.; Schwarz, L R; Snyder, R.; Burchell, B; Ingelman-Sundberg, M; K. W. DE BOCK

    1996-01-01

    The hepatic metabolism of benzene is thought to be a prerequisite for its bony marrow toxicity. However, the complete pattern of benzene metabolites formed in the liver and their role in bone marrow toxicity are not fully understood. Therefore, benzene metabolism was studied in isolated rodent hepatocytes. Rat hepatocytes released benzene-1,2-dihydrodiol, hydroquinone (HQ), catechol (CT), phenol (PH), trans-trans-muconic acid, and a number of phase II metabolites such as PH sulfate and PH glu...

  7. (Liquid + liquid) equilibria for (benzene + cyclohexane + dimethyl sulfoxide) system at T = (298.15 or 303.15) K: Experimental data and correlation

    International Nuclear Information System (INIS)

    Graphical abstract: The selectivity of DMSO, is usually high. At 25 °C and atmospheric pressure, the selectivity coefficient can reach beyond 14, which means that DMSO can compete with some ionic liquids for extracting benzene from cyclohexane. So, DMSO has large potential to separate benzene from cyclohexane as a new extractant. - Highlights: • The highest selectivity coefficient is beyond 14 of DMSO at T = (298.15 or 303.15) K. • The data’s reliability is approved by the correlation of Othmer–Tobias equation. • NRTL model is in good agreement with the experimental data. - Abstract: (Liquid + liquid) equilibrium (LLE) data were measured experimentally at T = (298.15 or 303.15) K and atmospheric pressure for the (benzene + cyclohexane + dimethyl sulfone (DMSO)) system. The Othmer–Tobias equation was applied to verify the reliability of the data. Based on the data, the selectivity of DMSO was estimated and compared with that of ionic liquids. The highest selectivity coefficient of DMSO can reach beyond 14, which means it is able to compete with some ionic liquids and it would be a good extractant to separate benzene from cyclohexane. At the same time, the NRTL model was used to correlate the data and the results show that the model agrees on the experimental data very well

  8. Aromaticity in benzene-like rings - An experimental electron density investigation

    Indian Academy of Sciences (India)

    Anupama Ranganathan; G U Kulkarni

    2003-10-01

    An experimental charge density study has been carried out on perylene based on X-ray diffraction measurements at 130 K. The electron density and its associated properties have been evaluated at the bond and the ring critical points for the naphthalene residues as well as for the central ring. The variation of the Laplacian along the axis, above and below the ring plane, is found to be symmetric for the central ring while for the naphthalene rings, the Laplacian values are enhanced under the bow-shaped region. A plot of the Laplacian versus density evaluated at various points along the axis above the ring plane, shows a steep variation in the case of the central ring implying that the -density is smeared out compared to that over the naphthalene rings. Similar data extracted from a quinoid ring and a regular phenyl ring (both based on earlier reports from this laboratory) exhibit increasingly shallower trends and indicate, by contrast, that the central ring of perylene is much less aromatic.

  9. Experimental and theoretical studies of the structural and electronic properties of vanadium–benzene sandwich clusters and their anions: V{sub n}Bz{sub n}{sup 0/−} (n = 1–5) and V{sub n}Bz{sub n−1}{sup 0/−} (n = 2–5)

    Energy Technology Data Exchange (ETDEWEB)

    Masubuchi, Tsugunosuke [Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Iwasa, Takeshi [Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); JST, ERATO, Nakajima Designer Nanocluster Assembly Project, 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012 (Japan); Nakajima, Atsushi, E-mail: nakajima@chem.keio.ac.jp [Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); JST, ERATO, Nakajima Designer Nanocluster Assembly Project, 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012 (Japan); Keio Institute of Pure and Applied Sciences (KiPAS), Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

    2014-12-07

    One end open V{sub n}Bz{sub n}{sup −} (n = 1–5; Bz = benzene) and both ends open V{sub n}Bz{sub n−1}{sup −} (n = 2–5) vanadium–benzene cluster anions were studied using anion photoelectron spectroscopy and density functional calculations. The smaller (n ≤ 3) V{sub n}Bz{sub n} and V{sub n}Bz{sub n−1} clusters and corresponding anions were found to have structural isomers, whereas full-sandwiched V{sub n}Bz{sub n+1} clusters preferred to form multiple-decker sandwich structures. Several isomeric V{sub 2}Bz{sub 2} structures were identified theoretically and the anion photoelectron spectra of V{sub 2}Bz{sub 2}{sup 0/−} were explained well by the coexistence of two isomeric structures: (1) a V{sub 2}-core structure sandwiched between benzene molecules and (2) an alternating sandwich structure with the spin state strongly dependent on the structure. The adiabatic electron affinity of both V{sub n}Bz{sub n} and V{sub n}Bz{sub n−1} was found to increase with the cluster size at larger sizes (n = 4 or 5) and approaches to that of V{sub n}Bz{sub n+1}. The evolution of the structural and electronic properties of V{sub n}Bz{sub m} and V{sub n}Bz{sub m}{sup −} (m = n and n − 1) with size is discussed in comparison with V{sub n}Bz{sub n+1} and V{sub n}Bz{sub n+1}{sup −}.

  10. Rice-ball structures of iron-benzene clusters, Fe{sub 4}-(C{sub 6}H{sub 6}){sub m}, m Less-Than-Or-Slanted-Equal-To 3. A density functional study

    Energy Technology Data Exchange (ETDEWEB)

    Valencia, Israel; Tavizon, Gustavo; Barba-Behrens, Norah [Departamento de Fisica y Quimica Teorica, DEPg. Facultad de Quimica, Universidad Nacional Autonoma de Mexico, C.P. 04510, Mexico D.F. (Mexico); Departamento de Quimica Inorganica, DEPg. Facultad de Quimica, Universidad Nacional Autonoma de Mexico, C.P. 04510, Mexico D.F. (Mexico); Castro, Miguel, E-mail: castro@quetzal.pquim.unam.mx [Departamento de Fisica y Quimica Teorica, DEPg. Facultad de Quimica, Universidad Nacional Autonoma de Mexico, C.P. 04510, Mexico D.F. (Mexico); Departamento de Quimica Inorganica, DEPg. Facultad de Quimica, Universidad Nacional Autonoma de Mexico, C.P. 04510, Mexico D.F. (Mexico)

    2011-11-18

    Graphical abstract: Adsorption of benzene molecules on Fe{sub 4} cluster. Highlights: Black-Right-Pointing-Pointer We studied the interactions of iron clusters with benzene molecules. Black-Right-Pointing-Pointer We have used density functional theory based methods for Fe{sub 4} and benzene. Black-Right-Pointing-Pointer The physicochemical properties were determined for the ground states. Black-Right-Pointing-Pointer The ground state structures for the Fe{sub 4}-benzene species were determined. - Abstract: Geometrical rice-ball structures of the Fe{sub 4} cluster with capped adsorbed benzene molecules for neutral, anion, and cation species, Fe{sub 4}-(C{sub 6}H{sub 6}){sub m} (m Less-Than-Or-Slanted-Equal-To 3), are studied by means of all-electron calculations done with the BPW91 approach of density functional theory jointly with 6-311++G(2d, 2p) basis sets. Electronic properties like ionization energies and electron affinities as well as binding energies are estimated and are in good agreement with recently reported experimental results. The computed IR spectra for these species show vibrational bands near those of the isolated benzene molecule and some forbidden IR modes of this ligand become IR active in Fe{sub 4}-(C{sub 6}H{sub 6}){sub m} (m Less-Than-Or-Slanted-Equal-To 3). The metal-benzene bonding issue was studied through the contour plots of molecular orbitals, showing signatures of metal-carbon bonding, originated from the 3d electrons of Fe{sub 4} and the 2p{pi} electrons of benzene.

  11. Evaluation of seawater contamination with benzene, toluene and xylene in the Ubatuba north coast, SP region, and study of their removal by ionizing radiation

    International Nuclear Information System (INIS)

    A major concern with leaking petroleum is the environmental contamination by the toxic and low water-soluble components such as benzene, toluene, and xylenes (BTX). These hydrocarbons have relatively high pollution potential because of their significant toxicity. The objective of this study was to evaluate the contamination of seawater by the main pollutants of the output and transport of petroleum, such as benzene, toluene, and xylene, and their removal by the exposure to the ionizing radiation. The studied region was Ubatuba region, SP, between 23 deg 26'S and 23 deg 46'S of latitude and 45 deg 02'W and 45 deg 11'W of longitude, area of carry and output of petroleum, and samples were collected from November, 2003 to July, 2005. For BTX in seawater analysis, the Purge and Trap concentrator with FIDGC detector showed significantly higher sensibility than Head Space concentrator with MSGC detector. The minimal detected limits (MDL) obtained at FIDGC were of 0.50 μg/L for benzene, 0.70 μg/L for toluene, and 1.54 μg/L for xylene, and the obtained experimental variability was 15%. While the concentrator type Headspace system with MS detector showed higher MLD, about of 9.30 mg/L for benzene, 8.50 mg/L for toluene, and 9.80 mg/L for xylene, and 10% of experimental variability. In the studied area the benzene concentration varied from 1.0 μg/L to 2.0 μg/L, the concentration of toluene varied from 60Co, presented a removal from 10% to 40% of benzene at 20 kGy absorbed doses and concentration of 35.1 mg/L and 70.2 mg/L, respectively; from 20% to 60% of toluene removal with 15 kGy absorbed dose and from 20% to 80% of xylene with 15 kGy absorbed dose in similar concentrations. (author)

  12. Benzene release. Status report

    International Nuclear Information System (INIS)

    Scoping benzene release measurements were conducted on 4 wt percent KTPB 'DEMO' formulation slurry using a round, flat bottomed 100-mL flask containing 75 mL slurry. The slurry was agitated with a magnetic stirrer bar to keep the surface refreshed without creating a vortex. Benzene release measurements were made by purging the vapor space at a constant rate and analyzing for benzene by gas chromatography with automatic data acquisition. Some of the data have been rounded or simplified in view of the scoping nature of this study

  13. An Evaluation of a Teat Dip with Dodecyl Benzene Sulfonic Acid in Preventing Bovine Mammary Gland Infection from Experimental Exposure to Streptococcus agalactiae and Staphylococcus aureus

    OpenAIRE

    Barnum, D A; Johnson, R. E.; Brooks, B W

    1982-01-01

    The effectiveness of a teat dip with dodecyl benzene sulfonic acid (1.94%) for the prevention of intramammary infections was determined in cows experimentally challenged with Streptococcus agalactiae and Staphylococcus aureus. The infection rates with Streptococcus agalactiae and Staphylococcus aureus were 62.5% and 75% in undipped quarters, 12.5% and 21.5% in dipped quarters with a reduction rate of 80% and 71% respectively. The significance of some findings in relation to mastitis control a...

  14. Spectroscopic study of water-NaCl-benzene mixtures at high temperatures and pressures

    OpenAIRE

    Ohya, Tomoyuki; Kitagawa, Masaaki; Jin, Yusuke; Ikawa, Shun-ichi

    2005-01-01

    Near-infrared and ultraviolet spectra of water-NaCl-benzene mixtures have been measured in the 473–573 K and 100–400 bar range and 373–498 K and 50–300 bar range, respectively. Concentrations of water in the benzene-rich phase and benzene in the water-rich phase were estimated from integrated intensities of the absorption bands. It is found that addition of NaCl in the aqueous phase suppresses transfer of water into the benzene-rich phase, and the relative decrease in water solubility in ...

  15. Coarse-grained molecular dynamics studies of cluster-bombarded benzene crystals

    International Nuclear Information System (INIS)

    As high-energy cluster projectile beams become standard analysis probes for SIMS, simulating larger crystals is now a requirement for the modeling community due to the large sputtering yields. As crystals get larger, computer resources become a limitation. Even though computer technology has evolved to include large memory systems and fast processors, there are still issues with having sufficient resources to run a calculation. This manuscript reports a method of studying a full crystal of benzene after impact with a 500 eV C60 projectile using a coarse-grained model. The potentials developed for this model incorporate the C-H bond of benzene into a single coarse-grained bead. This coarse-grained method has several advantages over atomistic models-the amount of time to perform these calculations has been drastically reduced and the potentials for this sample are pair-wise additive potentials. A discussion is made as to how these results compare to those obtained with fully atomistic calculations using the AIREBO potential

  16. Current understandings and perspectives on non-cancer health effects of benzene: A global concern

    Energy Technology Data Exchange (ETDEWEB)

    Bahadar, Haji [International Campus, Tehran University of Medical Sciences (Iran, Islamic Republic of); Pharmaceutical Sciences Research Center and Faculty of Pharmacy, Tehran University of Medical Sciences (Iran, Islamic Republic of); Mostafalou, Sara [Pharmaceutical Sciences Research Center and Faculty of Pharmacy, Tehran University of Medical Sciences (Iran, Islamic Republic of); Abdollahi, Mohammad, E-mail: Mohammad.Abdollahi@UToronto.Ca [Pharmaceutical Sciences Research Center and Faculty of Pharmacy, Tehran University of Medical Sciences (Iran, Islamic Republic of)

    2014-04-15

    Objective: Benzene, as a volatile organic compound, is known as one of the main air pollutants in the environment. The aim of this review is to summarize all available evidences on non-cancerous health effects of benzene providing an overview of possible association of exposure to benzene with human chronic diseases, specially, in those regions of the world where benzene concentration is being poorly monitored. Methodology: A bibliographic search of scientific databases including PubMed, Google Scholar, and Scirus was conducted with key words of “benzene toxic health effects”, “environmental volatile organic compounds”, “diabetes mellitus and environmental pollutants”, “breast cancer and environmental pollution”, “prevalence of lung cancer”, and “diabetes prevalence”. More than 300 peer reviewed papers were examined. Experimental and epidemiologic studies reporting health effects of benzene and volatile organic compounds were included in the study. Results: Epidemiologic and experimental studies suggest that benzene exposure can lead to numerous non-cancerous health effects associated with functional aberration of vital systems in the body like reproductive, immune, nervous, endocrine, cardiovascular, and respiratory. Conclusion: Chronic diseases have become a health burden of global dimension with special emphasis in regions with poor monitoring over contents of benzene in petrochemicals. Benzene is a well known carcinogen of blood and its components, but the concern of benzene exposure is more than carcinogenicity of blood components and should be evaluated in both epidemiologic and experimental studies. Aspect of interactions and mechanism of toxicity in relation to human general health problems especially endocrine disturbances with particular reference to diabetes, breast and lung cancers should be followed up. - Highlights: • Benzene is a volatile organic compound and established blood carcinogen. • Exposure to benzene needs to be

  17. Current understandings and perspectives on non-cancer health effects of benzene: A global concern

    International Nuclear Information System (INIS)

    Objective: Benzene, as a volatile organic compound, is known as one of the main air pollutants in the environment. The aim of this review is to summarize all available evidences on non-cancerous health effects of benzene providing an overview of possible association of exposure to benzene with human chronic diseases, specially, in those regions of the world where benzene concentration is being poorly monitored. Methodology: A bibliographic search of scientific databases including PubMed, Google Scholar, and Scirus was conducted with key words of “benzene toxic health effects”, “environmental volatile organic compounds”, “diabetes mellitus and environmental pollutants”, “breast cancer and environmental pollution”, “prevalence of lung cancer”, and “diabetes prevalence”. More than 300 peer reviewed papers were examined. Experimental and epidemiologic studies reporting health effects of benzene and volatile organic compounds were included in the study. Results: Epidemiologic and experimental studies suggest that benzene exposure can lead to numerous non-cancerous health effects associated with functional aberration of vital systems in the body like reproductive, immune, nervous, endocrine, cardiovascular, and respiratory. Conclusion: Chronic diseases have become a health burden of global dimension with special emphasis in regions with poor monitoring over contents of benzene in petrochemicals. Benzene is a well known carcinogen of blood and its components, but the concern of benzene exposure is more than carcinogenicity of blood components and should be evaluated in both epidemiologic and experimental studies. Aspect of interactions and mechanism of toxicity in relation to human general health problems especially endocrine disturbances with particular reference to diabetes, breast and lung cancers should be followed up. - Highlights: • Benzene is a volatile organic compound and established blood carcinogen. • Exposure to benzene needs to be

  18. Benzene Monitor System report

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, R.R.

    1992-10-12

    Two systems for monitoring benzene in aqueous streams have been designed and assembled by the Savannah River Technology Center, Analytical Development Section (ADS). These systems were used at TNX to support sampling studies of the full-scale {open_quotes}SRAT/SME/PR{close_quotes} and to provide real-time measurements of benzene in Precipitate Hydrolysis Aqueous (PHA) simulant. This report describes the two ADS Benzene Monitor System (BMS) configurations, provides data on system operation, and reviews the results of scoping tests conducted at TNX. These scoping tests will allow comparison with other benzene measurement options being considered for use in the Defense Waste Processing Facility (DWPF) laboratory. A report detailing the preferred BMS configuration statistical performance during recent tests has been issued under separate title: Statistical Analyses of the At-line Benzene Monitor Study, SCS-ASG-92-066. The current BMS design, called the At-line Benzene Monitor (ALBM), allows remote measurement of benzene in PHA solutions. The authors have demonstrated the ability to calibrate and operate this system using peanut vials from a standard Hydragard{trademark} sampler. The equipment and materials used to construct the ALBM are similar to those already used in other applications by the DWPF lab. The precision of this system ({+-}0.5% Relative Standard Deviation (RSD) at 1 sigma) is better than the purge & trap-gas chromatograpy reference method currently in use. Both BMSs provide a direct measurement of the benzene that can be purged from a solution with no sample pretreatment. Each analysis requires about five minutes per sample, and the system operation requires no special skills or training. The analyzer`s computer software can be tailored to provide desired outputs. Use of this system produces no waste stream other than the samples themselves (i.e. no organic extractants).

  19. Benzene exposure is associated with epigenetic changes (Review).

    Science.gov (United States)

    Fenga, Concettina; Gangemi, Silvia; Costa, Chiara

    2016-04-01

    Benzene is a volatile aromatic hydrocarbon solvent and is known as one of the predominant air pollutants in the environment. Chronic exposure to benzene is known to cause aplastic anemia and increased risk of acute myelogenous leukemia in humans. Although the mechanisms by which benzene causes toxicity remain to be fully elucidated, it is widely accepted that its metabolism is crucial to its toxicity, with involvement of one or more reactive metabolites. Novel approaches aimed at evaluating different mechanisms by which benzene can impact on human health by altering gene regulation have been developed. Among these novel approaches, epigenetics appears to be promising. The present review article summarizes the most important findings, reported from the literature, on epigenetic modifications correlated to benzene exposure. A computerized search in PubMed was performed in November 2014, using search terms, including 'benzene', 'epigenetic', 'histone modifications', 'DNA methylation' and 'microRNA'. Epidemiological and experimental studies have demonstrated the potential epigenetic effects of benzene exposure. Several of the epigenomic changes observed in response to environmental exposures may be mechanistically associated with susceptibility to diseases. However, further elucidation of the mechanisms by which benzene alters gene expression may improve prediction of the toxic potential of novel compounds introduced into the environment, and allow for more targeted and appropriate disease prevention strategies. PMID:26936331

  20. Charged vanadium-benzene multidecker clusters: DFT and quantum Monte Carlo study.

    Science.gov (United States)

    Tokár, K; Derian, R; Mitas, L; Štich, I

    2016-02-14

    Using explicitly correlated fixed-node quantum Monte Carlo and density functional theory (DFT) methods, we study electronic properties, ground-state multiplets, ionization potentials, electron affinities, and low-energy fragmentation channels of charged half-sandwich and multidecker vanadium-benzene systems with up to 3 vanadium atoms, including both anions and cations. It is shown that, particularly in anions, electronic correlations play a crucial role; these effects are not systematically captured with any commonly used DFT functionals such as gradient corrected, hybrids, and range-separated hybrids. On the other hand, tightly bound cations can be described qualitatively by DFT. A comparison of DFT and quantum Monte Carlo provides an in-depth understanding of the electronic structure and properties of these correlated systems. The calculations also serve as a benchmark study of 3d molecular anions that require a balanced many-body description of correlations at both short- and long-range distances. PMID:26874484

  1. Charged vanadium-benzene multidecker clusters: DFT and quantum Monte Carlo study

    Science.gov (United States)

    Tokár, K.; Derian, R.; Mitas, L.; Štich, I.

    2016-02-01

    Using explicitly correlated fixed-node quantum Monte Carlo and density functional theory (DFT) methods, we study electronic properties, ground-state multiplets, ionization potentials, electron affinities, and low-energy fragmentation channels of charged half-sandwich and multidecker vanadium-benzene systems with up to 3 vanadium atoms, including both anions and cations. It is shown that, particularly in anions, electronic correlations play a crucial role; these effects are not systematically captured with any commonly used DFT functionals such as gradient corrected, hybrids, and range-separated hybrids. On the other hand, tightly bound cations can be described qualitatively by DFT. A comparison of DFT and quantum Monte Carlo provides an in-depth understanding of the electronic structure and properties of these correlated systems. The calculations also serve as a benchmark study of 3d molecular anions that require a balanced many-body description of correlations at both short- and long-range distances.

  2. Charged vanadium-benzene multidecker clusters: DFT and quantum Monte Carlo study

    International Nuclear Information System (INIS)

    Using explicitly correlated fixed-node quantum Monte Carlo and density functional theory (DFT) methods, we study electronic properties, ground-state multiplets, ionization potentials, electron affinities, and low-energy fragmentation channels of charged half-sandwich and multidecker vanadium-benzene systems with up to 3 vanadium atoms, including both anions and cations. It is shown that, particularly in anions, electronic correlations play a crucial role; these effects are not systematically captured with any commonly used DFT functionals such as gradient corrected, hybrids, and range-separated hybrids. On the other hand, tightly bound cations can be described qualitatively by DFT. A comparison of DFT and quantum Monte Carlo provides an in-depth understanding of the electronic structure and properties of these correlated systems. The calculations also serve as a benchmark study of 3d molecular anions that require a balanced many-body description of correlations at both short- and long-range distances

  3. Charged vanadium-benzene multidecker clusters: DFT and quantum Monte Carlo study

    Energy Technology Data Exchange (ETDEWEB)

    Tokár, K.; Derian, R. [Institute of Physics, CCMS, Slovak Academy of Sciences, 84511 Bratislava (Slovakia); Mitas, L. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-8202 (United States); Štich, I., E-mail: ivan.stich@savba.sk [Institute of Physics, CCMS, Slovak Academy of Sciences, 84511 Bratislava (Slovakia); Ruprecht A. Institute of Technology, Bratislava (Slovakia)

    2016-02-14

    Using explicitly correlated fixed-node quantum Monte Carlo and density functional theory (DFT) methods, we study electronic properties, ground-state multiplets, ionization potentials, electron affinities, and low-energy fragmentation channels of charged half-sandwich and multidecker vanadium-benzene systems with up to 3 vanadium atoms, including both anions and cations. It is shown that, particularly in anions, electronic correlations play a crucial role; these effects are not systematically captured with any commonly used DFT functionals such as gradient corrected, hybrids, and range-separated hybrids. On the other hand, tightly bound cations can be described qualitatively by DFT. A comparison of DFT and quantum Monte Carlo provides an in-depth understanding of the electronic structure and properties of these correlated systems. The calculations also serve as a benchmark study of 3d molecular anions that require a balanced many-body description of correlations at both short- and long-range distances.

  4. Active phase of a Pd-Cu/ZSM-5 catalyst for benzene hydroxylation: in-situ XAFS studies

    International Nuclear Information System (INIS)

    The gas-phase hydroxylation of benzene by using a mixture of oxygen and hydrogen has been carried out over Cu/ZSM-5 catalysts modified with palladium. In-situ X-ray absorption studies employed in the course of H2-temperature programmed reduction (H2-TPR) followed by benzene hydroxylation confirmed that the oxidic phase of Cu2+ was transformed to Cu+ during the reaction. The addition of Pd to Cu/ZSM-5 noticeably improved the reducibility of the oxidic Cu phase, which resulted in an increase in the activity of the reaction.

  5. Study and Pilot Scale Development of Catalyst for Ethylebenzene Synthesis Through Transalkylation of Benzene and Polyethylbenzene

    Institute of Scientific and Technical Information of China (English)

    Wang Jin; Zhang Fengmei; Li Minglin; Hao Xiaoming; Shu Xingtian; He Mingyuan

    2002-01-01

    This paper refers to the results of study and development of benzene and polyethylbenzene transalkylation catalyst (type AEB-1) for synthesis of ethylbenzene. The effect of reaction conditions on the reaction performance of the catalyst was investigated in the pressurized microreactor CDS-900. A transalkylation catalyst with high activity, good selectivity and stability was developed following a 2000-hour test on the activity and stability of the catalyst. The preparation of this catalyst was implemented in pilot scale and this catalyst was tested for activity and stability in a 150 t/a pilot unit for production of ethylbenzene. The test results have shown that this transalkylation catalyst has excellent activity, selectivity and stability. The operation of pilot test unit ran smoothly and the process scheme is viable.

  6. Theoretical study of benzene and pyridine STM-induced reactions on copper surfaces

    International Nuclear Information System (INIS)

    Density functional theory calculations are used to determine the adiabatic reaction pathways of STM-induced reactions of benzene and pyridine molecules on Cu(100), Cu(110) and Cu(111). The studied reactions are rupture of the molecular ring as well as dehydrogenation of the molecules. In order to establish the final fragments of the reactions, the inelastic electron tunneling spectra of the molecules are analyzed and rationalized in terms of the electronic structure of the system. Besides vibrational excitation, the impinging electron confers on the molecule a dynamical evolution that depends on the capacity of the system to damp the excess energy. We predict that in the limit of heavy fragments, and hence for the heaviest isotopes, the STM bias voltage will match the computed adiabatic barriers

  7. Comparative Studies of 1,4-Bis[ 2-(4-Pyridyl) ethenyl ]-benzene Using Density Functional Theory

    Institute of Scientific and Technical Information of China (English)

    CHENG Jian-bo; L(U) Jia-ping; GONG Bao-an; LI Wen-zuo

    2007-01-01

    The optimized molecular structure and harmonic vibrational frequencies of a 1,4-bis [ 2-( 4-pyridyl ) ethenyl ] -benzene(BPENB) molecule were calculated via five popular density functional theory(DFT) methods. On the basis of the comparison between calculated and experimental results, it is concluded that the B3PW91 and B3LYP methods are superior to the others in optimizing structures, and the BPW91 method reproduces the observed fundamental frequencies most satisfactorily.

  8. Study of Humidity Effect on Benzene Decomposition by the Dielectric Barrier Discharge Nonthermal Plasma Reactor

    Science.gov (United States)

    Ma, Tianpeng; Zhao, Qiong; Liu, Jianqi; Zhong, Fangchuan

    2016-06-01

    The humidity effects on the benzene decomposition process were investigated by the dielectric barrier discharge (DBD) plasma reactor. The results showed that the water vapor played an important role in the benzene oxidation process. It was found that there was an optimum humidity value for the benzene removal efficiency, and at around 60% relative humidity (RH), the optimum benzene removal efficiency was achieved. At a SIE of 378 J/L, the removal efficiency was 66% at 0% RH, while the removal efficiency reached 75.3% at 60% RH and dropped to 69% at 80% RH. Furthermore, the addition of water inhibited the formation of ozone and NO2 remarkably. Both of the concentrations of ozone and NO2 decreased with increasing of the RH at the same specific input energy. At a SIE of 256 J/L, the concentrations of ozone and NO2 were 5.4 mg/L and 1791 ppm under dry conditions, whereas they were only 3.4 mg/L and 1119 ppm at 63.5% RH, respectively. Finally, the outlet gas after benzene degradation was qualitatively analyzed by FT-IR and GC-MS to determine possible intermediate byproducts. The results suggested that the byproducts in decomposition of benzene primarily consisted of phenol and substitutions of phenol. Based on these byproducts a benzene degradation mechanism was proposed. supported by National Natural Science Foundation of China (Nos. 11205007 and 11205029)

  9. Influence of van der Waals forces on the adsorption structure of benzene on silicon studied using density functional theory

    DEFF Research Database (Denmark)

    Johnston, Karen; Kleis, Jesper; Lundqvist, Bengt;

    2008-01-01

    Two different adsorption configurations of benzene on the Si(001)-(2×1) surface, the tight-bridge and butterfly structures, were studied using density functional theory. Several exchange and correlation functionals were used, including the recently developed van der Waals density functional (vd...

  10. Study on Kinetics of Hydrogen Absorption by Metal Hydride Slurries Ⅱ. Hydrogenation of Benzene Catalyzed by MlNi5

    Institute of Scientific and Technical Information of China (English)

    安越; 陈长聘; 徐国华; 蔡官明; 王启东

    2002-01-01

    The feasibility of the hydrogenation of benzene into cyclohexane over the hydrogen storage alloy MlNi5 catalyst was studied in the temperature range of 402~463 K. The results show that the reaction order is zero and the energy of activation is 28.9 kJmol-1.

  11. Benzene adsorption on PtCo(1 1 1): A DFT study

    International Nuclear Information System (INIS)

    Adsorption benzene on PtCo(1 1 1) surface at low coverage is investigated using density functional theory calculations. We have investigated the PtCo FCT alloy surface with a uniform distribution and two-benzene orientation on the surface. It was found that the most favorable site is a Co-Co bridge with an adsorption energy of −0.37 eV. A large buckling for the first Co and Pt atoms on the surface layers and a 17–30° H-tilt angles are found. The bonding analysis indicates that C-C and C-H bonding increase while Pt-Pt, Co-Co and Pt-Co decrease 13.2, 73 and 33%, respectively, after adsorption benzene. The vibrational frequencies of adsorbed benzene were also calculated.

  12. Immunoprophylactic potential of wheat grass extract on benzene-induced leukemia: An in vivo study on murine model

    Directory of Open Access Journals (Sweden)

    Neelofar Khan

    2015-01-01

    Full Text Available Objectives: Wheat grass (Triticum aestivum is a gift of nature given to mankind. A number of scientific research on wheatgrass establishes its anticancer and antioxidant potential. Current work was focused to determine antileukemic effect of wheat grass. Materials and Methods: The commercial wheatgrass powder was extracted with 95% of methanol. Methanol extract of wheat grass was studied for acute oral toxicity as per revised Organization for Economic Cooperation and Development Guidelines number 423. Leukemia was successfully induced in Wister rats by intravenous injection of benzene. The blood was collected and analyzed for hematological parameters. Phagocytotic activity of the extract was determined. Results : Phytochemical screening revealed the presence of flavonoids, phenolics, carbohydrates, and amino acids. From acute toxicity studies, it was found that the methanol extract of wheatgrass was safe up to a dose level of 2000 mg/kg of body weight. Outcomes of hematological parameters in various experimental groups of murine model demonstrated antileukemic effect of extract. Methanol extract of wheatgrass aroused the process of phagocytosis of killed Candida albicans and also demonstrated a significant chemotactic activity at all tested concentrations. Conclusion: In the current work, methanol extract of wheat grass demonstrated antileukemic potential that might be due to the presence of flavonoids and polyphenolics in it. Further isolation, structural characterization of active constituents is necessary to extrapolate the mechanism of action.

  13. A Density Functional Theory Study of the Adsorption of Benzene on Hematite (α-Fe2O3 Surfaces

    Directory of Open Access Journals (Sweden)

    Nelson Y. Dzade

    2014-02-01

    Full Text Available The reactivity of mineral surfaces in the fundamental processes of adsorption, dissolution or growth, and electron transfer is directly tied to their atomic structure. However, unraveling the relationship between the atomic surface structure and other physical and chemical properties of complex metal oxides is challenging due to the mixed ionic and covalent bonding that can occur in these minerals. Nonetheless, with the rapid increase in computer processing speed and memory, computer simulations using different theoretical techniques can now probe the nature of matter at both the atomic and sub-atomic levels and are rapidly becoming an effective and quantitatively accurate method for successfully predicting structures, properties and processes occurring at mineral surfaces. In this study, we have used Density Functional Theory calculations to study the adsorption of benzene on hematite (α-Fe2O3 surfaces. The strong electron correlation effects of the Fe 3d-electrons in α-Fe2O3 were described by a Hubbard-type on-site Coulomb repulsion (the DFT+U approach, which was found to provide an accurate description of the electronic and magnetic properties of hematite. For the adsorption of benzene on the hematite surfaces, we show that the adsorption geometries parallel to the surface are energetically more stable than the vertical ones. The benzene molecule interacts with the hematite surfaces through π-bonding in the parallel adsorption geometries and through weak hydrogen bonds in the vertical geometries. Van der Waals interactions are found to play a significant role in stabilizing the absorbed benzene molecule. Analyses of the electronic structures reveal that upon benzene adsorption, the conduction band edge of the surface atoms is shifted towards the valence bands, thereby considerably reducing the band gap and the magnetic moments of the surface Fe atoms.

  14. Computational and Experimental Assessment of Benzene Cation Chemistry for the Measurement of Marine Derived Biogenic Volatile Organic Compounds with Chemical Ionization Mass Spectrometry

    Science.gov (United States)

    Zoerb, M.; Kim, M.; Zimmermann, K.; Bertram, T. H.

    2013-12-01

    Chemical ionization mass spectrometry (CIMS) is a highly selective and sensitive technique for the measurement of trace gases in the atmosphere. However, competing side reactions and dependence on relative humidity (RH) can make the transition from the laboratory to the field challenging. Effective implementation of chemical ionization requires a thorough knowledge of the elementary steps leading to ionization of the analyte. We have recently investigated benzene cations for the detection of marine derived biogenic volatile organic compounds (BVOCs), such isoprene and terpene compounds, from algal bloom events. Our experimental results indicate that benzene ion chemistry is an attractive candidate for field measurements, and the RH dependence is weak. To further understand the advantages and limitations of this approach, we have also used electronic structure theory calculations to compliment the experimental work. These theoretical methods can provide valuable insight into the physical chemistry of ion molecule reactions including thermodynamical information, the stability of ions to fragmentation, and potential sources of interference such as dehydration to form isobaric ions. The combined experimental and computational approach also allows validation of the theoretical methods and will provide useful information towards gaining predictive power for the selection of appropriate reagent ions for future experiments.

  15. Species differences in the metabolism of benzene.

    OpenAIRE

    Henderson, R F

    1996-01-01

    The pathways of metabolism of benzene appear to be qualitatively similar in all species studied thus far. However, there are quantitative differences in the fraction of benzene metabolized by the different pathways. These species differences become important for risk assessments based on animal data. Mice have a greater overall capacity to metabolize benzene than rats or primates, based on mass balance studies conducted in vivo using radiolabled benzene. Mice and monkeys metabolize more of th...

  16. Species differences in the metabolism of benzene

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, R.F. [Inhalation Toxicology Research Institute, Albuquerque, NM (United States)

    1996-12-01

    The pathways of metabolism of benzene appear to be qualitatively similar in all species studied thus far. However, there are quantitative differences in the fraction of benzene metabolized by the different pathways. These species differences become important for risk assessments based on animal data. Mice have a greater overall capacity to metabolize benzene than rats or primates, based on mass balance studies conducted in vivo using radiolabled benzene. Mice and monkeys metabolize more of the benzene to hydroquinone metabolites than do rats or chimpanzees, especially at low doses. Nonhuman primates metabolize less of the benzene to muconic acid than do rodents or humans. In all species studied, a greater proportion of benzene is converted to hydroquinone and ring-breakage metabolites at low doses than at high doses. This finding should be considered in attempting to extrapolate the toxicity of benzene observed at high doses to predicted toxicity at low doses. Because ring-breakage metabolites and hydroquinone have both been implicated in the toxicity of benzene, the higher formation of those metabolites in the mouse may partially explain why mice are more sensitive to benzene than are rats. Metabolism of benzene in humans, the species of interest, does not exactly mimic that of any animal species studied. More information on the urinary and blood metabolites of occupationally exposed people is required to determine the fractional conversion of benzene to putative toxic metabolites and the degree of variability present in human subjects. 12 refs., 4 tabs.

  17. Theoretical Study on the Complexes of Benzene with Isoelectronic Nitrogen-Containing Heterocycles

    Czech Academy of Sciences Publication Activity Database

    Wang, Weizhou; Hobza, Pavel

    2008-01-01

    Roč. 9, č. 7 (2008), s. 1003-1009. ISSN 1439-4235 R&D Projects: GA MŠk LC512; GA AV ČR IAA400550510 Institutional research plan: CEZ:AV0Z40550506 Keywords : benzene * benzenecomplexes * blue shift Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.636, year: 2008

  18. Studies on Ion-molecule Reaction of Disubstituted Benzene with IonSystem of Acetyl Chloride in Gas Phase

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The ion-molecule reactions of disubstituted benzenes with the ion system of acetyl chloride under the chemical ionization condition were examined and the fragmentation reactions of the adduct ions formed by the ion-molecule reactions were studied by using collision-induced dissocia tion technique. It was found that the electron-releasing groups favored the adduct reactions and the electron-withdrawing groups did not. The position and properties of substituting groups had an effect on the relative abundance of the adduct ions. The fragmentation reaction of the adduct ions formed by ortho-benzene diamine with the acetyl ion was similar to the reductive alkylation reaction of amine in condensed phase.

  19. Nonlinear diffusion in Acetone-Benzene Solution

    CERN Document Server

    Obukhovsky, Vjacheslav V

    2010-01-01

    The nonlinear diffusion in multicomponent liquids under chemical reactions influence has been studied. The theory is applied to the analysis of mass transfer in a solution of acetone-benzene. It has been shown, that the creation of molecular complexes should be taken into account for the explanation of the experimental data on concentration dependence of diffusion coefficients. The matrix of mutual diffusivities has been found and effective parameters of the system have been computed.

  20. Marine environmental protection: An application of the nanometer photo catalyst method on decomposition of benzene.

    Science.gov (United States)

    Lin, Mu-Chien; Kao, Jui-Chung

    2016-04-15

    Bioremediation is currently extensively employed in the elimination of coastal oil pollution, but it is not very effective as the process takes several months to degrade oil. Among the components of oil, benzene degradation is difficult due to its stable characteristics. This paper describes an experimental study on the decomposition of benzene by titanium dioxide (TiO2) nanometer photocatalysis. The photocatalyst is illuminated with 360-nm ultraviolet light for generation of peroxide ions. This results in complete decomposition of benzene, thus yielding CO2 and H2O. In this study, a nonwoven fabric is coated with the photocatalyst and benzene. Using the Double-Shot Py-GC system on the residual component, complete decomposition of the benzene was verified by 4h of exposure to ultraviolet light. The method proposed in this study can be directly applied to elimination of marine oil pollution. Further studies will be conducted on coastal oil pollution in situ. PMID:26922359

  1. The study of basis sets for the calculation of the structure and dynamics of the benzene-Kr complex

    International Nuclear Information System (INIS)

    An ab initio intermolecular potential energy surface (PES) has been constructed for the benzene-krypton (BKr) van der Waals (vdW) complex. The interaction energy has been calculated at the coupled cluster level of theory with single, double, and perturbatively included triple excitations using different basis sets. As a result, a few analytical PESs of the complex have been determined. They allowed a prediction of the complex structure and its vibrational vdW states. The vibrational energy level pattern exhibits a distinct polyad structure. Comparison of the equilibrium structure, the dipole moment, and vibrational levels of BKr with their experimental counterparts has allowed us to design an optimal basis set composed of a small Dunning’s basis set for the benzene monomer, a larger effective core potential adapted basis set for Kr and additional midbond functions. Such a basis set yields vibrational energy levels that agree very well with the experimental ones as well as with those calculated from the available empirical PES derived from the microwave spectra of the BKr complex. The basis proposed can be applied to larger complexes including Kr because of a reasonable computational cost and accurate results

  2. The study of basis sets for the calculation of the structure and dynamics of the benzene-Kr complex

    Energy Technology Data Exchange (ETDEWEB)

    Shirkov, Leonid; Makarewicz, Jan, E-mail: jama@amu.edu.pl [Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań (Poland)

    2015-05-28

    An ab initio intermolecular potential energy surface (PES) has been constructed for the benzene-krypton (BKr) van der Waals (vdW) complex. The interaction energy has been calculated at the coupled cluster level of theory with single, double, and perturbatively included triple excitations using different basis sets. As a result, a few analytical PESs of the complex have been determined. They allowed a prediction of the complex structure and its vibrational vdW states. The vibrational energy level pattern exhibits a distinct polyad structure. Comparison of the equilibrium structure, the dipole moment, and vibrational levels of BKr with their experimental counterparts has allowed us to design an optimal basis set composed of a small Dunning’s basis set for the benzene monomer, a larger effective core potential adapted basis set for Kr and additional midbond functions. Such a basis set yields vibrational energy levels that agree very well with the experimental ones as well as with those calculated from the available empirical PES derived from the microwave spectra of the BKr complex. The basis proposed can be applied to larger complexes including Kr because of a reasonable computational cost and accurate results.

  3. Spatial variability in levels of benzene, formaldehyde, and total benzene, toluene, ethylbenzene and xylenes in New York City: a land-use regression study

    Directory of Open Access Journals (Sweden)

    Kheirbek Iyad

    2012-07-01

    Full Text Available Abstract Background Hazardous air pollutant exposures are common in urban areas contributing to increased risk of cancer and other adverse health outcomes. While recent analyses indicate that New York City residents experience significantly higher cancer risks attributable to hazardous air pollutant exposures than the United States as a whole, limited data exist to assess intra-urban variability in air toxics exposures. Methods To assess intra-urban spatial variability in exposures to common hazardous air pollutants, street-level air sampling for volatile organic compounds and aldehydes was conducted at 70 sites throughout New York City during the spring of 2011. Land-use regression models were developed using a subset of 59 sites and validated against the remaining 11 sites to describe the relationship between concentrations of benzene, total BTEX (benzene, toluene, ethylbenzene, xylenes and formaldehyde to indicators of local sources, adjusting for temporal variation. Results Total BTEX levels exhibited the most spatial variability, followed by benzene and formaldehyde (coefficient of variation of temporally adjusted measurements of 0.57, 0.35, 0.22, respectively. Total roadway length within 100 m, traffic signal density within 400 m of monitoring sites, and an indicator of temporal variation explained 65% of the total variability in benzene while 70% of the total variability in BTEX was accounted for by traffic signal density within 450 m, density of permitted solvent-use industries within 500 m, and an indicator of temporal variation. Measures of temporal variation, traffic signal density within 400 m, road length within 100 m, and interior building area within 100 m (indicator of heating fuel combustion predicted 83% of the total variability of formaldehyde. The models built with the modeling subset were found to predict concentrations well, predicting 62% to 68% of monitored values at validation sites. Conclusions Traffic and

  4. Multiphoton ionization studies of benzene in tetramethylsilane and n-pentane solutions

    International Nuclear Information System (INIS)

    The multiphoton ionization spectra of dilute solutions (approx. -3 M) of benzene in tetramethylsilane (TMSi) and n-pentane (n-Pt) have been measured using linearly polarized light over the laser excitation wavelength (λ/sub exc/) region from 360 to 560 nm. Spectra measured with circularly polarized light are also reported for 460 <λ/sub exc/<540 nm. The order of the multiphoton ionization mechanisms that occur in different λ/sub exc/ regions has been determined, and their importance is discussed together with the observed polarization behavior. The polarization ratio and the ''apparent'' order of the ionization process were found to depend on the laser intensity. The ionization threshold of benzene in TMSi was estimated to lie between 6.6 and 5.9 eV, while in n-Pt between 7.36 and 6.8 eV

  5. Small-angle neutron scattering studies of sodium butyl benzene sulfonate aggregates in aqueous solution

    Indian Academy of Sciences (India)

    O R Pal; V G Gaikar; J V Joshi; P S Goyal; V K Aswal

    2004-08-01

    The aggregation behaviour of a hydrotrope, sodium -butyl benzene sulfonate (Na-NBBS), in aqueous solutions is investigated by small-angle neutron scattering (SANS). Nearly ellipsoidal aggregates of Na-NBBS at concentrations well above its minimum hydrotrope concentration were detected by SANS. The hydrotrope seems to form self-assemblies with aggregation number of 36–40 with a substantial charge on the aggregate. This aggregation number is weakly affected by the hydrotrope concentration.

  6. A STUDY ON THE DEGRADATION MECHANISM OF PHOTOCROSSLINKING PRODUCTS FORMED BY CYCLIZED POLYISOPRENE-DIAZIDE SYSTEM UNDER THE INFLUENCE OF ALKYL BENZENE SULFONIC ACIDS

    Institute of Scientific and Technical Information of China (English)

    HUANG Junlian; SUN Meng

    1989-01-01

    The degradation mechanism of photocrosslinking products formed by cyclized polyisoprene-diazide system under the influence of the different alkyl benzene sulfonic acids was studied. The effects ofalkyl chain length and the concentration of alkyl benzene sulfonic acids on the rate of degradation reaction were discussed. It was found that in the initial stage of degradation, the cyclicity ratio and the average fused ring number did not change considerably, but the percentage of uncyclized parts content varied significantly. The suitable mechanism was supposed.

  7. Albumin Adducts of Electrophilic Benzene Metabolites in Benzene-Exposed and Control Workers

    OpenAIRE

    Lin, Yu-Sheng; Vermeulen, Roel; Tsai, Chin H.; Waidyanatha, Suramya; Lan, Qing; Rothman, Nathaniel; Smith, Martyn T.; Zhang, Luoping; Shen, Min; Li, Guilan; Yin, Songnian; Kim, Sungkyoon; Rappaport, Stephen M.

    2006-01-01

    Background Metabolism of benzene produces reactive electrophiles, including benzene oxide (BO), 1,4-benzoquinone (1,4-BQ), and 1,2-benzoquinone (1,2-BQ), that are capable of reacting with blood proteins to produce adducts. Objectives The main purpose of this study was to characterize relationships between levels of albumin adducts of these electrophiles in blood and the corresponding benzene exposures in benzene-exposed and control workers, after adjusting for important covariates. Because se...

  8. Synthesis, molecular structure and DFT studies of tricarbonylrhenium(I) complexes containing nitrogen based bis, tris, tetrakis-(di-2-pyridylaminomethyl)benzene ligands

    Science.gov (United States)

    Sangilipandi, S.; Sutradhar, Dipankar; Kaminsky, Werner; Chandra, Asit K.; Mohan Rao, K.

    2016-07-01

    The reactions of rhenium starting precursor with the corresponding N,N‧-bidentate 2,2‧-dipyridylamine ligands (L1-L5) in toluene medium under nitrogen atmosphere leads to the formation of mononuclear tricarbonylrhenium(I) complexes. These complexes are denoted by general formula fac-[Re(L) (CO)3Br] (1-5); where, L = 1,2-bis(di-2-pyridylaminomethyl)benzene (L1), 1,3-bis(di-2-pyridylaminomethyl)benzene (L2), 1,4-bis(di-2-pyridylaminomethyl)benzene (L3), 1,3,5-tris(di-2-pyridylaminomethyl)benzene (L4) and 1,2,4,5-tetrakis(di-2-pyridylaminomethyl)benzene (L5). All these complexes have been synthesized and characterized by FT-IR, 1H NMR, UV-Vis and mass spectroscopic techniques. Emission spectrum for these complexes has also been investigated and found that complex (5) shows maximum emission as compared to other complexes. Moreover, two of the complexes (2 &4) were structurally determined by single crystal X-ray diffraction analysis. The time-dependent DFT calculations were carried out for the complexes (2, 4 &5) which show good agreement with the experimental absorption data.

  9. Effect of repeated benzene inhalation exposures on benzene metabolism, binding to hemoglobin, and induction of micronuclei

    International Nuclear Information System (INIS)

    Metabolism of benzene is thought to be necessary to produce the toxic effects, including carcinogenicity, associated with benzene exposure. To extrapolate from the results of rodent studies to potential health risks in man, one must know how benzene metabolism is affected by species, dose, dose rate, and repeated versus single exposures. The purpose of our studies was to determine the effect of repeated inhalation exposures on the metabolism of [14C]benzene by rodents. Benzene metabolism was assessed by characterizing and quantitating urinary metabolites, and by quantitating 14C bound to hemoglobin and micronuclei induction. F344/N rats and B6C3F1 mice were exposed, nose-only, to 600 ppm benzene or to air (control) for 6 hr/day, 5 days/week for 3 weeks. On the last day, both benzene-pretreated and control animals were exposed to 600 ppm, 14C-labeled benzene for 6 hr. Individual benzene metabolites in urine collected for 24 hr after the exposure were analyzed. There was a significant decrease in the respiratory rate of mice (but not rats) pretreated with benzene which resulted in lower levels of urinary [14C]benzene metabolites. The analyses indicated that the only effects of benzene pretreatment on the metabolite profile in rat or mouse urine were a slight shift from glucuronidation to sulfation in mice and a shift from sulfation to glucuronidation in rats. Benzene pretreatment also had no effect, in either species, on formation of [14C]benzene-derived hemoglobin adducts. Mice and rats had similar levels of hemoglobin adduct binding, despite the higher metabolism of benzene by mice. This indicates that hemoglobin adduct formation occurs with higher efficiency in rats. After 1 week of exposure to 600 ppm benzene, the frequency of micronucleated, polychromatic erythrocytes (PCEs) in mice was significantly increased

  10. Aggregation of Benzene Molecules with Molecules of Methanol and Formic Acid

    International Nuclear Information System (INIS)

    Calculations and experimental studies of Raman scattering spectra show that there is a dimeric aggregation of benzene molecules with the molecule of methyl alcohol with the use of π-electrons of the benzene ring. In this process, the H-active hydrogen atom of O-H group is oriented to the edge of the benzene ring (a distance along the normal to the plane of the benzene ring is 2.850 A). The unusual position of the H-active hydrogen atom is conditioned by the interaction of two hydrogen atoms of the alcohols methyl group with π-electrons of the benzene ring. In Raman scattering spectra, the aggregation of molecules in the liquid state of the substance leads to a broadening of the band of full-symmetric vibrations with the maximum at 992 cm-1, as well as to a shift of this band toward lower frequencies by ∼ 1 cm-1. The band at 992 cm-1 is narrowed more than twice at the strong dilution of the benzene-methyl alcohol mixture by a large amount of heptane. The aggregation of benzene molecules takes place also with the molecules of formic acid with the use of π-electrons of the benzene ring. As in the case of the benzene-methyl alcohol mixture, the H-active hydrogen atom of O-H group of the acid is shifted toward the edge of the benzene ring. The energy of the benzene-formic acid dimerization is 9.2 kJ/mole.

  11. Spectroscopic study on deuterated benzenes. III. Vibronic structure and dynamics in the S1 state

    Science.gov (United States)

    Kunishige, Sachi; Katori, Toshiharu; Kawabata, Megumi; Yamanaka, Takaya; Baba, Masaaki

    2015-12-01

    We observed the fluorescence excitation spectra and mass-selected resonance enhanced multiphoton ionization (REMPI) excitation spectra for the 6 01 , 6 01 10 1 , and 6 01 10 2 bands of the S1←S0 transition of jet-cooled deuterated benzene and assigned the vibronic bands of C6D6 and C6HD5. The 60 1 10 n (n = 0, 1, 2) and 00 0 transition energies were found to be dependent only on the number of D atoms (ND), which was reflected by the zero-point energy of each H/D isotopomer. In some isotopomers some bands, such as those of out-of-plane vibrations mixed with 611n, make the spectra complex. These included the 611021n level or combination bands with ν12 which are allowed because of reduced molecular symmetry. From the lifetime measurements of each vibronic band, some enhancement of the nonradiative intramolecular vibrational redistribution (IVR) process was observed. It was also found that the threshold excess energy of "channel three" was higher than the 6112 levels, which were similar for all the H/D isotopomers. We suggest that the channel three nonradiative process could be caused mainly by in-plane processes such as IVR and internal conversion at the high vibrational levels in the S1 state of benzene, although the out-of-plane vibrations might contribute to some degree.

  12. Benzene destruction in claus process by sulfur dioxide: A reaction kinetics study

    KAUST Repository

    Sinha, Sourab

    2014-07-02

    Benzene, toluene and xylene (BTX) are present as contaminants in the H 2S gas stream entering a Claus furnace. The exhaust gases from the furnace enter catalytic units, where BTX form soot particles. These particles clog and deactivate the catalysts. A solution to this problem is BTX oxidation before the gases enter catalyst beds. This work presents a theoretical investigation on benzene oxidation by SO2. Density functional theory is used to develop a detailed mechanism for phenyl radical -SO2 interactions. The mechanism begins with SO2 addition to phenyl radical after overcoming an energy barrier of 6.4 kJ/mol. This addition reaction is highly exothermic, where a reaction energy of 182 kJ/mol is released. The most favorable pathway involves O-S bond breakage, leading to the release of SO. A remarkable similarity between the pathways for phenyl radical oxidation by O2 and its oxidation by SO2 is observed. The reaction rate constants are also evaluated to facilitate process simulations. © 2014 American Chemical Society.

  13. Spectroscopic [FT-IR and FT-Raman] and molecular modeling (MM) study of benzene sulfonamide molecule using quantum chemical calculations

    Science.gov (United States)

    Vinod, K. S.; Periandy, S.; Govindarajan, M.

    2016-07-01

    The spectroscopic and molecular modeling (MM) study includes, FT-IR, FT-Raman and 13C NMR and 1H NMR spectra of the Benzene sulfonamide were recorded for the analysis. The observed experimental and theoretical frequencies (IR and Raman) were assigned according to their distinctive region. The present study of this title molecule have been carried out by hybrid computational calculations of HF and DFT (B3LYP) methods with 6-311+G(d,p) and 6-311++G(d,p) basis sets and the corresponding results are tabulated. The structural modifications of the compound due to the substitutions of NH2 and SO2 were investigated. The minimum energy conformers of the compound were studied using conformational analysis. The alternations of the vibrational pattern of the base structure related to the substitutions were analyzed. The thermodynamic parameters (such as zero-point vibrational energy, thermal energy, specific heat capacity, rotational constants, entropy, and dipole moment) of Benzene sulfonamide have been calculated. The donor acceptor interactions of the compound and the corresponding UV transitions are found out using NBO analysis. The NMR spectra were simulated by using the gauge independent atomic orbital (GIAO) method with B3LYP methods and the 6-311++G(d,p) basis set and their spectra were simulated and the chemical shifts related to TMS were compared. A quantum computational study on the electronic and optical properties absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by HF and DFT methods. The energy gap of the present compound was calculated related to HOMO and LUMO energies which confirm the occurring of charge transformation between the base and ligand group. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. The thermodynamic properties (heat capacity, entropy, and enthalpy) of the title compound at different temperatures were calculated in gas phase and

  14. Spectroscopic study on deuterated benzenes. I. Microwave spectra and molecular structure in the ground state

    International Nuclear Information System (INIS)

    We observed microwave absorption spectra of some deuterated benzenes and accurately determined the rotational constants of all H/D isotopomers in the ground vibrational state. Using synthetic analysis assuming that all bond angles are 120°, the mean bond lengths were obtained to be r0(C–C) = 1.3971 Å and r0(C–H) = r0(C–D) = 1.0805 Å. It has been concluded that the effect of deuterium substitution on the molecular structure is negligibly small and that the mean bond lengths of C–H and C–D are identical unlike small aliphatic hydrocarbons, in which r0(C–D) is about 5 mÅ shorter than r0(C–H). It is considered that anharmonicity is very small in the C–H stretching vibration of aromatic hydrocarbons

  15. Spectroscopic study on deuterated benzenes. I. Microwave spectra and molecular structure in the ground state

    Energy Technology Data Exchange (ETDEWEB)

    Kunishige, Sachi; Katori, Toshiharu; Baba, Masaaki, E-mail: baba@kuchem.kyoto-u.ac.jp [Division of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Nakajima, Masakazu; Endo, Yasuki [Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902 (Japan)

    2015-12-28

    We observed microwave absorption spectra of some deuterated benzenes and accurately determined the rotational constants of all H/D isotopomers in the ground vibrational state. Using synthetic analysis assuming that all bond angles are 120°, the mean bond lengths were obtained to be r{sub 0}(C–C) = 1.3971 Å and r{sub 0}(C–H) = r{sub 0}(C–D) = 1.0805 Å. It has been concluded that the effect of deuterium substitution on the molecular structure is negligibly small and that the mean bond lengths of C–H and C–D are identical unlike small aliphatic hydrocarbons, in which r{sub 0}(C–D) is about 5 mÅ shorter than r{sub 0}(C–H). It is considered that anharmonicity is very small in the C–H stretching vibration of aromatic hydrocarbons.

  16. Ultrasonic and viscosimetric studies of samarium laurate in benzene-dimethylsulfoxide mixtures

    International Nuclear Information System (INIS)

    Ultrasonic and viscosity measurements of samarium laurate in benzene-DMSO mixtures of different compositions (7:3 and 1:1 V/V) have been used to determine the critical micelle concentration (CMC), soap-solvent interaction, and various acoustic parameters of the system. The values of critical micelle concentration increase with increasing amount of DMSO in the solvent mixtures. The viscosity results have been explained on the basis of equations proposed by Einstein, Vand. Moulik, and Jones-Dole. The values of CMC for samarium laurate obtained from the viscosity measurements are in agreement with the results obtained from ultrasonic measurements. The results show that the soap molecules do not aggregate appreciably below CMC there is a marked change in the aggregation behaviour at CMC. (author)

  17. Electrochemical behaviour of benzene on platinum electrodes

    OpenAIRE

    Montilla Jiménez, Francisco; Huerta Arráez, Francisco; Morallón Núñez, Emilia; Vázquez Picó, José Luis

    1999-01-01

    The adsorption and oxidation of benzene in acidic media on platinum electrodes (polycrystalline and single-crystal electrodes) have been studied by cyclic voltammetry and in-situ Fourier transform infrared spectroscopy. The oxidation characteristics of benzene depend on the surface structure of the platinum electrode used. In all platinum electrodes studied, the main reduction product of benzene is cyclohexane, and the oxidation products detected by infrared spectroscopy have been CO2 and ben...

  18. Molecular motion of benzene, n-hexane, and cyclohexane in potassium zeolite L studied by deuterium NMR

    International Nuclear Information System (INIS)

    The molecular motions of perdeuterated benzene, n-hexane, and cyclohexane sorbed at loading levels of 1 molecule per channel lobe (or, equivalently, per unit cell) in potassium zeolite L have been examined by 2H nuclear magnetic resonance (NMR) for 100 K ≤ T ≤ 350 K. Benzene (C6D6) gives a broad signal with, for T 6H14) also shows no evidence for isotropic motion. Two distinct spectral components, associated respectively with the methyl and methylene deuterons, are observed. The magnitudes of the 2H quadrupolar coupling strengths can be interpreted solely in terms of torsional rotations about the carbon-carbon bonds. The temperature dependence of the 2H spin-lattice relaxation processes suggests an activation energy of ∼ 2 kcal mol-1 for these C-C bond rotations, consistent with earlier studies of bond rotation in alkanes. Sorbed cyclohexane (C6D12) shows a transition in the dynamical behavior (on the time scale of the 2H NMR experiment) in the vicinity of 280 K. Close to 280 K , a narrow signal is observed consistent with effectively isotropic reorientations, but both above and below 280 K there is a significant residual quadrupole interaction. The narrow component decreases rapidly with temperature, becoming unobservable below 230 K

  19. Spectroscopic study on deuterated benzenes. III. Vibronic structure and dynamics in the S(1) state.

    Science.gov (United States)

    Kunishige, Sachi; Katori, Toshiharu; Kawabata, Megumi; Yamanaka, Takaya; Baba, Masaaki

    2015-12-28

    We observed the fluorescence excitation spectra and mass-selected resonance enhanced multiphoton ionization (REMPI) excitation spectra for the 6(0)(1), 6(0)(1)1(0)(1), and 6(0)(1)1(0)(2) bands of the S1←S0 transition of jet-cooled deuterated benzene and assigned the vibronic bands of C6D6 and C6HD5. The 6(0)(1)1(0)(n) (n = 0, 1, 2) and 0(0)(0) transition energies were found to be dependent only on the number of D atoms (ND), which was reflected by the zero-point energy of each H/D isotopomer. In some isotopomers some bands, such as those of out-of-plane vibrations mixed with 6(1)1(n), make the spectra complex. These included the 6(1)10(2)1(n) level or combination bands with ν12 which are allowed because of reduced molecular symmetry. From the lifetime measurements of each vibronic band, some enhancement of the nonradiative intramolecular vibrational redistribution (IVR) process was observed. It was also found that the threshold excess energy of "channel three" was higher than the 6(1)1(2) levels, which were similar for all the H/D isotopomers. We suggest that the channel three nonradiative process could be caused mainly by in-plane processes such as IVR and internal conversion at the high vibrational levels in the S1 state of benzene, although the out-of-plane vibrations might contribute to some degree. PMID:26723668

  20. Experimental studies of vircator

    Energy Technology Data Exchange (ETDEWEB)

    Xie Wenkai; Qian Guangdi; Meng Lin; Liu Shenggang [Univ. of Electronic Science and Technology of China, Chengdu, Sichuan (China). Inst. of High Energy Electronics

    1995-11-01

    An experimental device of special high impedance, low beam current vircator is designed by means of the pulse-line electronic beam accelerator at UESTC according to the principle of virtual cathode microwave oscillator. A gradient varying region is linked between the drift tube and the diode in order to reducing the impedance of the diode. A strong pulse longitudinal magnetic field is applied, on the diode-drift region. A special plate-cathode mesh-anode, structure is applied, there are annular grooves with 2. 5mm spaced and 60{degree} on the cathode. Numerical analysis of the experimental system is performed. The operation modes and output power of signal are determined. The output power in X-band is greater than 27Mw, and the efficiency is above 1.0%.

  1. Products of the Benzene + O(3P) Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Taatjes, Craig A.; Osborn, David L.; Selby, Talitha M.; Meloni, Giovanni; Trevitt, Adam J.; Epifanovsky, Evgeny; Krylov, Anna I.; Sirjean, Baptiste; Dames, Enoch; Wang, Hai

    2009-12-21

    The gas-phase reaction of benzene with O(3P) is of considerable interest for modeling of aromatic oxidation, and also because there exist fundamental questions concerning the prominence of intersystem crossing in the reaction. While its overall rate constant has been studied extensively, there are still significant uncertainties in the product distribution. The reaction proceeds mainly through the addition of the O atom to benzene, forming an initial triplet diradical adduct, which can either dissociate to form the phenoxy radical and H atom, or undergo intersystem crossing onto a singlet surface, followed by a multiplicity of internal isomerizations, leading to several possible reaction products. In this work, we examined the product branching ratios of the reaction between benzene and O(3P) over the temperature range of 300 to 1000 K and pressure range of 1 to 10 Torr. The reactions were initiated by pulsed-laser photolysis of NO2 in the presence of benzene and helium buffer in a slow-flow reactor, and reaction products were identified by using the multiplexed chemical kinetics photoionization mass spectrometer operating at the Advanced Light Source (ALS) of Lawrence Berkeley National Laboratory. Phenol and phenoxy radical were detected and quantified. Cyclopentadiene and cyclopentadienyl radical were directly identified for the first time. Finally, ab initio calculations and master equation/RRKM modeling were used to reproduce the experimental branching ratios, yielding pressure-dependent rate expressions for the reaction channels, including phenoxy + H, phenol, cyclopentadiene + CO, which are proposed for kinetic modeling of benzene oxidation.

  2. Traffic-related air pollution and the onset of myocardial infarction: disclosing benzene as a trigger? A small-area case-crossover study.

    Directory of Open Access Journals (Sweden)

    Denis Bard

    Full Text Available Exposure to traffic is an established risk factor for the triggering of myocardial infarction (MI. Particulate matter, mainly emitted by diesel vehicles, appears to be the most important stressor. However, the possible influence of benzene from gasoline-fueled cars has not been explored so far.We conducted a case-crossover study from 2,134 MI cases recorded by the local Coronary Heart Disease Registry (2000-2007 in the Strasbourg Metropolitan Area (France. Available individual data were age, gender, previous history of ischemic heart disease and address of residence at the time of the event. Nitrogen dioxide, particles of median aerodynamic diameter <10 µm (PM10, ozone, carbon monoxide and benzene air concentrations were modeled on an hourly basis at the census block level over the study period using the deterministic ADMS-Urban air dispersion model. Model input data were emissions inventories, background pollution measurements, and meteorological data. We have found a positive, statistically significant association between concentrations of benzene and the onset of MI: per cent increase in risk for a 1 µg/m3 increase in benzene concentration in the previous 0, 0-1 and 1 day was 10.4 (95% confidence interval 3-18.2, 10.7 (2.7-19.2 and 7.2 (0.3-14.5, respectively. The associations between the other pollutants and outcome were much lower and in accordance with the literature.We have observed that benzene in ambient air is strongly associated with the triggering of MI. This novel finding needs confirmation. If so, this would mean that not only diesel vehicles, the main particulate matter emitters, but also gasoline-fueled cars--main benzene emitters-, should be taken into account for public health action.

  3. Natural Biological Attenuation of Benzene in Groundwater

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Benzene has been found in subsurface unsaturated soil and groundwater beneath a petro-chemical plant. Although the groundwater contained several mg/L of benzene in the area immediately beneath the source, benzene was not detected in monitoring wells approximately 800m down stream. All kinds of physical processes such as adsorption and advection/dispersion are considered to account for the observed attenuation. The results indicated that the attenuation was primarily due to natural biological processes occurring within the aquifer. The evidence for the natural bioremediation of benzene from the groundwater included: (1) analysis of groundwater chemistry, (2) laboratory studies demonstrating benzene biodegradation in aquifer samples, and (3) computer simulations examining benzene transport. Laboratory experiments indicated that for conditions similar to those in the plume, the aerobic degradation of benzene by the naturally occurring microorganisms in the polluted groundwater samples was quite rapid with a half-life time of from 5 to 15 days. In situ analyses indicated the level of dissolved oxygen in the groundwater was over 2mg/L. Thus, oxygen should not limit the biodegradation. In fact, the benzene was also shown to degrade under anaerobic conditions. The results from the modeling simulations indicate that biodegradation is the dominant process influencing attenuation of the benzene.

  4. Study on Kinetics of Hydrogen Absorption by Metal Hydride Slurries Ⅰ. Absorption of Hydrogen by Hydrogen Storage Alloy MlNi5 Suspended in Benzene

    Institute of Scientific and Technical Information of China (English)

    安越; 陈长聘; 徐国华; 蔡官明; 王启东

    2002-01-01

    The absorption of hydrogen was studied in metal hydride slurry, which is formed by benzene and hydrogen storage alloy powder. The influence of temperature on the rate of absorption was discussed using three-phase mass transfer model. It is also concluded that the suitable absorption temperature is 313 K.

  5. Benzene from Traffic

    DEFF Research Database (Denmark)

    Palmgren, F.; Berkowicz, R.; Skov, H.;

    The measurements of benzene showed very clear decreasing trends in the air concentrations and the emissions since 1994. At the same time the measurements of CO and NOx also showed a decreasing trend, but not so strong as for benzene. The general decreasing trend is explained by the increasing...... number of petrol vehicles with three way catalysts, 60-70% in 1999. The very steep decreasing trend for benzene at the beginning of the period from 1994 was explained by the combination of more catalyst vehicles and reduced benzene content in Danish petrol. The total amount of aromatics in petrol......, including toluene, increased only weakly. The analyses of air concentrations were confirmed by analyses of petrol sold in Denmark. The concentration of benzene at Jagtvej in Copenhagen is still in 1998 above the expected new EU limit value, 5 µg/m3 as annual average. However, the reduced content of benzene...

  6. A theoretical study on the aromaticity of benzene and related derivatives incorporating a C-C C-C fragment

    Czech Academy of Sciences Publication Activity Database

    Sanchez-Sanz, Goar; Trujillo, Cristina; Rozas, I.; Elguero, J.

    2013-01-01

    Roč. 69, č. 35 (2013), s. 7333-7344. ISSN 0040-4020 Institutional support: RVO:61388963 Keywords : dehydroannulenes * aromaticity * NICS * chemical shifts * benzene Subject RIV: CC - Organic Chemistry Impact factor: 2.817, year: 2013

  7. Molecular simulation and experimental study of CO2 absorption in ionic liquid reverse micelle.

    Science.gov (United States)

    Shi, Wei; Hong, Lei; Damodaran, Krishnan; Nulwala, Hunaid B; Luebke, David R

    2014-12-01

    The structure and dynamics for CO2 absorption in ionic liquid reverse micelle (ILRM) were studied using molecular simulations. The ILRM consisted of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) ionic liquid (IL) as the micelle core, the benzylhexadecyldimethylammonium ([BHD](+)) chloride ([Cl](-)) was the cationic surfactant, and benzene was used as the continuous solvent phase in this study. The diffusivity values of this ILRM system were also experimentally determined. Simulations indicate that there is ion exchange between the IL anion ([BF4](-)) and the surfactant anion ([Cl](-)). It was also found that the [bmim][BF4] IL exhibits small local density at the interface region between the IL core and the [BHD](+) surfactant cation layer, which leads to a smaller density for the [bmim][BF4] IL inside the reverse micelle (RM) compared with the neat IL. These simulation findings are consistent with experimental results. Both our simulations and experimental results show that [bmim][BF4] inside the RM diffuses 5-26 times faster than the neat IL, which is partly due to the fast particle diffusion for the ILRM nanodroplet (IL and surfactant) as a whole in benzene solvent compared with neat [bmim][BF4] diffusion. Additionally, it was found that [bmim][BF4] IL solved in benzene diffuses 2 orders of magnitude faster than the neat IL. Lastly, simulations show that CO2 molecules are absorbed in four different regions of the ILRM system, that is, (I) in the IL inner core, (II) in the [BHD](+) surfactant cation layer, (III) at the interface between the [BHD](+) surfactant cation layer and benzene solvent, and (IV) in the benzene solvent. The CO2 solubility was found to decrease in the order II > III ∼ IV > I, while the CO2 diffusivity and permeability decrease in the following order: IV > III > II > I. PMID:25382316

  8. Mechanistic considerations in benzene physiological model development

    Energy Technology Data Exchange (ETDEWEB)

    Medinsky, M.A.; Kenyon, E.M.; Seaton, M.J.; Schlosser, P.M. [Chemical Industry Institute of Toxicology, Research Triangle Park, NC (United States)

    1996-12-01

    Benzene, an important industrial solvent, is also present in unleaded gasoline and cigarette smoke. The hematotoxic effects of benzene in humans are well documented and include aplastic anemia, pancytopenia, and acute myelogenous leukemia. However, the risks of leukemia at low exposure concentrations have not been established. A combination of metabolites (hydroquinone and phenol, for example) may be necessary to duplicate the hematotoxic effect of benzene, perhaps due in part to the synergistic effect of phenol on myeloperoxidase-mediated oxidation of hydroquinone to the reactive metabolite benzoquinone. Because benzene and its hydroxylated metabolites (phenol, hydroquinone, and catechol) are substrates for the same cytochrome P450 enzymes, competitive interactions among the metabolites are possible. In vivo data on metabolite formation by mice exposed to various benzene concentrations are consistent with competitive inhibition of phenol oxidation by benzene. In vitro studies of the metabolic oxidation of benzene, phenol, and hydroquinone are consistent with the mechanism of competitive interaction among the metabolites. The dosimetry of benzene and its metabolites in the target tissue, bone marrow, depends on the balance of activation processes such as enzymatic oxidation and deactivation processes such as conjugation and excretion. Phenol, the primary benzene metabolite, can undergo both oxidation and conjugation. Thus the potential exists for competition among various enzymes for phenol. Zonal localization of phase I and phase 11 enzymes in various regions of the liver acinus also impacts this competition. Biologically based dosimetry models that incorporate the important determinants of benzene flux, including interactions with other chemicals, will enable prediction of target tissue doses of benzene and metabolites at low exposure concentrations relevant for humans. 39 refs., 4 figs., 2 tabs.

  9. Application of nuclear reaction analysis to the study of hydrogen and benzene adsorption on monocrystals of nickel and of the alloy Pt50Ni50

    International Nuclear Information System (INIS)

    The main contribution of nuclear reaction analysis to studies of gas adsorption on surfaces comes from their ability to measure adsorbate concentrations lower than one monolayer with high accuracy, even in gas atmosphere and for a large pressure range. A detailed study of hydrogen analysis by the 1H(15N, αγ)12C nuclear reaction has allowed to define the analytical characteristics of these methods in connection with the various experimental parameters. Deuterium analysis by the 2D(15N, pγ16N and 2D(15N, nγ)16O nuclear reactions has allowed a study of coadsorption the benzene and hydrogen using D-labelled molecules, the carbon concentration being determined from the 12C(d, p0)13C and 13C(p, γ)14N nuclear reactions. The nuclear reaction on hydrogen has been firstly applied to the measurement of room temperature hydrogen coverage of Ni (111). The maximum surface coverage of 0.6 (± 0.05) monolayer is in good agreement with previously published values. Then, hydrogen adsorption on the (111) and (110) faces of Pt50 Ni50 alloy has been studied in the 115 K - 400 K temperature range and the 10-8 - 10-4 mbar pressure range. The hydrogen coverage at saturation, obtained for low temperature adsorption, is 0.92 (± 0.1) monolayer on the (110) face and 0.18 (± 0.04) monolayer on the (111) face. These values are notably lower than the saturation coverages of Ni and Pt single crystals. For the (110) surface, the hydrogen adsorption energy has been deduced from adsorption isobares and its variation as a function of the coverage determined. An interpretation of the results, taking into account the segregation profiles of the metallic atoms which are different for these two faces, is proposed. In a benzene - hydrogen coadsorption study on Ni (111), the measurement of hydrogen, deuterium and carbon concentrations on the surface has allowed to show that at room temperature the predominant surface reaction between the adsorbed molecules is the hydrogen atom exchange reaction

  10. Decomposition of benzene in air streams by UV/TiO2 process

    International Nuclear Information System (INIS)

    Photocatalytic decomposition of gaseous benzene at room temperature was studied with a fixed-bed annular reactor using titania as the photocatalyst. The effects of humidity, UV light intensity and benzene concentration on the conversion and mineralization of benzene were presented. Experimental results can be adequately described by using the Langmuir-Hinshelwood (L-H) kinetic model. The concentration distribution of benzene in the annular reactors of various dimensions can be described by combining the reactor design equation with L-H kinetics. Deactivation of catalyst was observed and attributed to the adsorption of reaction intermediates on TiO2 surface. The deactivated TiO2 catalyst could be photochemically regenerated by ozone-purging in the presence of humidity

  11. Four component catalysis for the hydroalkylation of benzene to cyclohexyl benzene

    Energy Technology Data Exchange (ETDEWEB)

    Fahy, J.; Trimm, D.L. [School of Chemical Engineering and Industrial Chemistry, University of New South Wales, NSW 2052 Sydney (Australia); Cookson, D.J. [BHP Melbourne Research Laboratories, Vic. Melbourne (Australia)

    2001-04-13

    Patent claims that benzene can be hydroalkylated to form cyclohexyl benzene - a potential diesel fuel - over a four component catalyst have been verified, and the role of the individual components has been explored. The hydrogenation of benzene over nickel on zeolite 13X produced reasonably high (ca. 30%) yields of cyclohexane, but the product distribution favoured cyclohexyl benzene in the presence of rare earth ions. The addition of small (ca. 1%) of platinum produced good yields and selectivities to cyclohexyl benzene at ca. 450K, a performance which was matched only at ca. 670K in the absence of platinum. Temperature programmed studies showed that Pt promoted the low temperature reduction of the catalyst to produce better performance. The acidic 13X molecular sieve promoted alkylation, but acidity was not the only factor involved. Rare earth additions were suggested to induce electron transfer to the nickel, weakening adsorption of benzene and promoting hydroalkylation rather than hydrogenation.

  12. Experimental studies of electron capture

    International Nuclear Information System (INIS)

    This thesis discusses the main results of recent experimental studies of electron capture in asymmetric collisions. Most of the results have been published, but the thesis also contains yet unpublished data, or data presented only in unrefereed conference proceedings. The thesis aims at giving a coherent discussion of the understanding of the experimental results, based first on simple qualitative considerations and subsequently on quantitative comparisons with the best theoretical calculations currently available. (Auth.)

  13. Densities and Kinematic Viscosities for the Systems Benzene + Methyl Formate, Benzene + Ethyl Formate, Benzene + Propyl Formate, and Benzene + Butyl Formate

    DEFF Research Database (Denmark)

    Emmerling, Uwe; Rasmussen, Peter

    1998-01-01

    Densities and kinematic viscosities have been measured for the system benzene + methyl formate at 20°C and for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate from 20°C to 50°C. The results for the system benzene + methyl formate have been correlated using...... a Redlich-Kister type of expression with temperature-independent parameters and the data for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate with temperature-dependent parameters. The viscosities have furthermore been compared to values predicted by means...

  14. Double photoionization of halogenated benzene

    International Nuclear Information System (INIS)

    We have experimentally investigated the double-photoionization process in C6BrF5 using monochromatized synchrotron radiation. We compare our results with previously published data for partially deuterated benzene (C6H3D3) over a wide range of photon energies from threshold to 270 eV. A broad resonance in the ratio of doubly to singly charged parent ions at about 65 eV appears shifted in energy compared to benzene data. This shift is due to the difference in the bond lengths in two molecules. A simple model can explain the shape of this resonance. At higher photon energies, we observe another broad resonance that can be explained as a second harmonic of the first resonance

  15. Double photoionization of halogenated benzene

    Energy Technology Data Exchange (ETDEWEB)

    AlKhaldi, Mashaal Q. [Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin (Germany); Wehlitz, Ralf, E-mail: rwehlitz@gmail.com [Synchrotron Radiation Center, University of Wisconsin–Madison, Stoughton, Wisconsin 53589 (United States)

    2016-01-28

    We have experimentally investigated the double-photoionization process in C{sub 6}BrF{sub 5} using monochromatized synchrotron radiation. We compare our results with previously published data for partially deuterated benzene (C{sub 6}H{sub 3}D{sub 3}) over a wide range of photon energies from threshold to 270 eV. A broad resonance in the ratio of doubly to singly charged parent ions at about 65 eV appears shifted in energy compared to benzene data. This shift is due to the difference in the bond lengths in two molecules. A simple model can explain the shape of this resonance. At higher photon energies, we observe another broad resonance that can be explained as a second harmonic of the first resonance.

  16. Tokamak experimental power reactor studies

    International Nuclear Information System (INIS)

    The principal results of a scoping and project definition study for the Tokamak Experimental Power Reactor are presented. Objectives are discussed; a preliminary conceptual design is described; detailed parametric, survey and sensitivity studies are presented; and research and development requirements are outlined. (U.S.)

  17. Theoretical Studies on the One- and Two-Photon Absorption Properties of Double-bis(styryl)benzene Derivatives

    Institute of Scientific and Technical Information of China (English)

    HAN,De-Ming; FENG,Ji-Kang; REN,Ai-Min; SHANG,Xiao-Hong; ZHANG,Xiang-Biao; MA,Yu-Guang; HE,Feng

    2008-01-01

    Two series of bis(styryl)benzene derivatives (BSBD), namely the single-BSBD and the double-BSBD, were investigated. The equilibrium geometries and electronic structures were obtained by using the density functional theory B3LYP and 6-31G basis set. In succession, the one- and two-photon absorption properties of all the molecules were studied theoretically with a ZINDO-SOS (sum-over-states) method in detail. It can be seen that the double-BSBDs have larger two-photon absorption (TPA) cross sections in the visible-IR range than the corresponding single-BSBDs,demonstrating that increasing the molecular dimension is a very effective method to enhance the values of the TPA cross sections. On the other hand, it can be also noticed that the values of the TPA cross sections are correlative with the ability of donating (accepting) electrons of the terminal substituent groups R[N(CH3)2, CH3, H and CF3] in these molecules. That is, the intramolecular charge transfer is also a factor for the enhancement of the TPA efficiency. To sum up, the idea of increasing the molecular dimension to enhance the TPA cross section value is a helpful direction to explore better TPA materials for practical applications. And the double-BSBD molecules are promising TPA materials for the further investigation from the standpoint of the high transparency and the larger TPA cross sections.

  18. The surface of ordered mesoporous benzene-silica hybrid material: an infrared and ab initio molecular modeling study.

    Science.gov (United States)

    Onida, Barbara; Borello, Luisa; Busco, Claudia; Ugliengo, Piero; Goto, Yasutomo; Inagaki, Shinji; Garrone, Edoardo

    2005-06-23

    Joint IR and computational results allow a detailed characterization of the surface properties of a mesoporous benzene-silica hybrid material with crystal-like wall structure. After outgassing at 450 degrees C, hydroxyl species mainly consist of noninteracting silanols, with both O-H and Si-O stretching modes at lower frequencies than those of SiOH in silica. Interaction with several probe molecules, followed both by experiment and calculus, shows that the aryl group in the coordination sphere of Si imparts a lesser acidity with respect to the isolated silanol in silica. In contrast, adsorption isotherms indicate that the interaction with acetone is stronger with benzene-silica than with silica: this is interpreted in terms of secondary interactions taking place between the slightly acidic CH in acetone and the electronic cloud in benzene-like rings. This suggests that both the inorganic component and the organic one play a role in dictating the surface behavior. PMID:16852474

  19. Experimental and predicted data of excess molar enthalpies and excess molar volumes for the ternary system (1,3-dichlorobenzene + benzene + 1-chlorohexane) at T = 298.15 K

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Experimental enthalpy and densitiy for the mixture 1,3-dichlorobenzene + benzene + 1-chlorohexane were measured. • The excess molar volumes were calculated from the densities of the pure liquids and their mixtures. • The Cibulka equation was used to correlate the ternary contribution of the excess molar properties. • The experimental data were used to test several empirical equations. - Abstract: Experimental excess molar enthalpies, densities and excess molar volumes for the ternary system {x1 1,3-dichlorobenzene + x2 benzene + (1 − x1 − x2) 1-chlorohexane} have been determined at the temperature of 298.15 K and atmospheric pressure. Values of excess molar enthalpies were measured using a Calvet microcalorimeter, and excess molar volumes were determined from the densities of the pure liquids and mixtures, using a vibrating-tube densimeter. The results were fitted by means of different variable degree polynomials. Smooth representations of the results are presented and used to construct constant contours of excess molar enthalpy and excess molar volume on Roozeboom diagrams. Several empirical expressions that have been suggested for use with parameters and predicting excess properties of ternary mixtures from the experimental binary data were tested

  20. Interphase cytogenetics of workers exposed to benzene

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, L.; Wang, Yunxia; Venkatesh, P. [Univ. of California, Berkeley, CA (United States)] [and others

    1996-12-01

    Fluorescence in situ hybridization (FISH) is a powerful new technique that allows numerical chromosome aberrations (aneuploidy) to be detected in interphase cells. In previous studies, FISH has been used to demonstrate that the benzene metabolites hydroquinone and 1,2,4-benzenetriol induce aneuploidy of chromosomes 7 and 9 in cultures of human cells. In the present study, we used an interphase FISH procedure to perform cytogenetic analyses on the blood cells of 43 workers exposed to benzene (median=31 ppm, 8-hr time-weighted average) and 44 matched controls from Shanghai, China. High benzene exposure (>31 ppm, n=22) increased the hyperdiploid frequency of chromosome 9 (p<0.01), but lower exposure (<31 ppm, n=21) did not. Trisomy 9 was the major form of benzene-induced hyperdiploidy. The level of hyperdiploidy in exposed workers correlated with their urinary phenol level (r= 0.58, p < 0.0001), a measure of internal benzene close. A significant correlation was also found between hyperdiploicly and decreased absolute lymphocyte count, an indicator of benzene hematotoxicity, in the exposed group (r=-0.44, p=0.003) but not in controls (r=-0.09, P=0.58). These results show that high benzene exposure induces aneuploidy of chromosome 9 in nondiseased individuals, with trisomy being the most prevalent form. They further highlight the usefulness of interphase cytogenetics and FISH for the rapid and sensitive detection of aneuploidy in exposed human populations. 35 refs., 3 figs., 2 tabs.

  1. EXPERIMENTAL STUDY ON THERMOCAPILLARY CONVECTION

    Institute of Scientific and Technical Information of China (English)

    束继祖

    2003-01-01

    In the present paper, the experimental studies on thermocapillary convection are reviewed. The author's interest is mainly focused on the onset of oscillatory thermocapillary convection,the features of oscillatory flow pattern, and the critical Marangoni number related with temperature and free surface oscillation. The coordinated measurement in a microgravity environment of a drop shaft is also addressed.

  2. Experimental Study on Hysucat Vessels

    Institute of Scientific and Technical Information of China (English)

    M.S.Seif; M.Askari

    2004-01-01

    The paper contains the results of an experimental study on a planing catamaran. The aim of this study is resistance reduction with application of foils. Experiments are performed in different conditions and the results are compared with each other. The foils are used in different configurations and it is concluded that unsuitable design may result in larger resistance. But, it is also shown that, for a good design, the resistance may be reduced considerably.

  3. Degradation of Benzene by Using a Silent-Packed Bed Hybrid Discharge Plasma Reactor

    Institute of Scientific and Technical Information of China (English)

    姜楠; 鲁娜; 李杰; 吴彦

    2012-01-01

    In this work, a novel gas phase silent-packed bed hybrid discharge plasma reactor has been proposed, and its ability to control a simulative gas stream containing 240 ppm benzene is experimentally investigated. In order to optimize the geometry of the reactor, the benzene conversion rate and energy yield (EY) were compared for various inner electrode diameters and quartz tube shapes and sizes. In addition, benzene removal efficiency in different discharge regions was qualitatively analyzed and the gas parameter (space velocity) was systematically studied. It has been found that silent-packed bed hybrid discharge plasma reactor can effectively decompose benzene. Benzene removal proved to achieve an optimum value of 60% with a characteristic energy density of 255 J/L in this paper with a 6 mm bolt high-voltage electrode and a 13 mm quartz tube. The optimal space velocity was 188.1 h^-1, which resulted in moderate energy yield and removal efficiency. Reaction by-products such as hydroquinone, heptanoic acid, 4-nitrocatechol, phenol and 4-phenoxy-phenol were identified by mean of GC-MS. In addition, based on these organic by-products, a benzene destruction pathway was proposed.

  4. Degradation of Benzene by Using a Silent-Packed Bed Hybrid Discharge Plasma Reactor

    Science.gov (United States)

    Jiang, Nan; Lu, Na; Li, Jie; Wu, Yan

    2012-02-01

    In this work, a novel gas phase silent-packed bed hybrid discharge plasma reactor has been proposed, and its ability to control a simulative gas stream containing 240 ppm benzene is experimentally investigated. In order to optimize the geometry of the reactor, the benzene conversion rate and energy yield (EY) were compared for various inner electrode diameters and quartz tube shapes and sizes. In addition, benzene removal efficiency in different discharge regions was qualitatively analyzed and the gas parameter (space velocity) was systematically studied. It has been found that silent-packed bed hybrid discharge plasma reactor can effectively decompose benzene. Benzene removal proved to achieve an optimum value of 60% with a characteristic energy density of 255 J/L in this paper with a 6 mm bolt high-voltage electrode and a 13 mm quartz tube. The optimal space velocity was 188.1 h-1, which resulted in moderate energy yield and removal efficiency. Reaction by-products such as hydroquinone, heptanoic acid, 4-nitrocatechol, phenol and 4-phenoxy-phenol were identified by mean of GC-MS. In addition, based on these organic by-products, a benzene destruction pathway was proposed.

  5. Facts about Benzene

    Science.gov (United States)

    ... Lab Info Chemical Emergencies A–Z Abrin Adamsite Ammonia Arsenic Arsine Barium Benzene Brevetoxin Bromine BZ Carbon ... used to make some types of lubricants, rubbers, dyes, detergents, drugs, and pesticides. How you could be ...

  6. Comparative study of the effects of toluene, benzene, 1,1,1-trichloroethane, diethyl ether, and flurothyl on anxiety and nociception in mice

    International Nuclear Information System (INIS)

    The main purpose of this study was to compare the effects of solvents from different chemical classes on anxiety and nociception. Independent groups of mice were exposed to air (control group), toluene (1000-4000 ppm), benzene (1000-4000 ppm), 1,1,1-trichloroethane (TCE, 2000-12000 ppm), diethyl ether (10,000-30,000) or flurothyl (200-600 ppm). After a 30-min exposure, animals were tested either in the anxiety paradigm conditioned defensive burying (CDB) test or in the hot plate test. All solvents but flurothyl produced anxiolytic-like actions being the order of potency toluene > benzene > TCE > diethyl ether. When tested in the hot plate paradigm, toluene and TCE increased nociception, benzene and diethyl ether had no effects, and flurothyl decreased nociception Additional groups of mice were conditioned to recognize the aversive stimulus (electrified prod) prior to toluene exposure and then tested in the CDB test. In unconditioned animals, toluene increased the number of shocks that mice received; however, when mice had previous experience in the CDB test, toluene lacked this effect. Taken together, these results show that inhalants have different effects with different potencies both in the CDB and in the hot plate tests. Additionally, data suggest that acute administration of toluene could impair learning

  7. Portfolio diversification: an experimental study

    OpenAIRE

    Gubaydullina, Zulia; Spiwoks, Markus

    2009-01-01

    The paper analyses on an experimental basis the phenomenon of non-optimal under-diversification in portfolio choice decisions and investigates the reasons behind it. The most important obstacles for optimal diversification are studied – the correlation neglect hypothesis and the overconfidence which both lead to suboptimal diversification decisions. The investment alternatives are constructed in a way that the Markowitz’ efficiency frontier is reduced to a single point in the return-risk diag...

  8. Iodine-benzene complex as a candidate for a real-time control of a bimolecular reaction. Spectroscopic studies of the properties of the 1:1 complex isolated in solid krypton.

    Science.gov (United States)

    Kiviniemi, Tiina; Hulkko, Eero; Kiljunen, Toni; Pettersson, Mika

    2009-06-01

    The properties of the 1:1 iodine-benzene complex isolated in a solid Kr matrix at low temperatures have been studied using UV-vis absorption, FTIR, resonance Raman, and femtosecond coherent anti-Stokes Raman spectroscopy (fs-CARS). The use of all these techniques on similar samples provides a wide view on the spectroscopic properties of the complex and allows comparison and combination of the results from different methods. The results for the complex cover its structure, the changes in the iodine molecule's vibrational frequencies and electronic absorption spectrum upon complexation, and the dynamics of the complexed I(2) molecule on both ground and excited electronic states. In addition, polarization beats between uncomplexed benzene and iodine molecules are detected in the fs-CARS spectra, showing an amplification of an electronically nonresonant CARS signal by the resonant iodine signal. The possibility of controlling the charge-transfer reaction of the I(2)-Bz complex using the excitation of a well-defined ground-state vibrational wavepacket, according to the Tannor-Rice-Kosloff scheme, is discussed on the basis of the experimental findings. PMID:19425545

  9. Spectroscopic study on deuterated benzenes. II. High-resolution laser spectroscopy and rotational structure in the S(1) state.

    Science.gov (United States)

    Kunishige, Sachi; Katori, Toshiharu; Baba, Masaaki; Hayashi, Masato; Hasegawa, Hirokazu; Ohshima, Yasuhiro

    2015-12-28

    High-resolution spectra of the S1←S0 transition in jet-cooled deuterated benzenes were observed using pulse dye amplification of single-mode laser light and mass-selective resonance enhanced multiphoton ionization (REMPI) detection. The vibrational and rotational structures were accurately analyzed for the vibronic levels in the S1 state. The degenerate 6(1) levels of C6H6 or C6D6 are split into 6a(1) and 6b(1) in many of deuterated benzenes. The rigid-rotor rotational constants were assessed and found to be slightly different between 6a and 6b because of different mean molecular structures. Their rotational levels are significantly shifted by Coriolis interactions. It was found that the Coriolis parameter proportionally changed with the number of substituted D atoms. PMID:26723667

  10. Spectroscopic study on deuterated benzenes. II. High-resolution laser spectroscopy and rotational structure in the S1 state

    Science.gov (United States)

    Kunishige, Sachi; Katori, Toshiharu; Baba, Masaaki; Hayashi, Masato; Hasegawa, Hirokazu; Ohshima, Yasuhiro

    2015-12-01

    High-resolution spectra of the S1←S0 transition in jet-cooled deuterated benzenes were observed using pulse dye amplification of single-mode laser light and mass-selective resonance enhanced multiphoton ionization (REMPI) detection. The vibrational and rotational structures were accurately analyzed for the vibronic levels in the S1 state. The degenerate 61 levels of C6H6 or C6D6 are split into 6a1 and 6b1 in many of deuterated benzenes. The rigid-rotor rotational constants were assessed and found to be slightly different between 6a and 6b because of different mean molecular structures. Their rotational levels are significantly shifted by Coriolis interactions. It was found that the Coriolis parameter proportionally changed with the number of substituted D atoms.

  11. Spectroscopic study on deuterated benzenes. II. High-resolution laser spectroscopy and rotational structure in the S1 state

    International Nuclear Information System (INIS)

    High-resolution spectra of the S1←S0 transition in jet-cooled deuterated benzenes were observed using pulse dye amplification of single-mode laser light and mass-selective resonance enhanced multiphoton ionization (REMPI) detection. The vibrational and rotational structures were accurately analyzed for the vibronic levels in the S1 state. The degenerate 61 levels of C6H6 or C6D6 are split into 6a1 and 6b1 in many of deuterated benzenes. The rigid-rotor rotational constants were assessed and found to be slightly different between 6a and 6b because of different mean molecular structures. Their rotational levels are significantly shifted by Coriolis interactions. It was found that the Coriolis parameter proportionally changed with the number of substituted D atoms

  12. Oxidation of benzene by the OH radical. A product and pulse radiolysis study in oxygenated aqueous solution

    International Nuclear Information System (INIS)

    Hydroxyl radicals have been reacted with benzene. The major product is phenol. At low dose rate (γ-radiolysis) it is formed in 53% yield with respect to the OH radical yield. This value increases to 93% in alkaline solution (pH 12.3). With deuteriated benzene it is reduced to 39%. In addition, more than fifteen different ring-opened and fragment products are formed. A good material balance (based on primary OH radical yield and oxygen consumption) was obtained. At high dose rate (pulse radiolysis) the major products are phenol, hydroquinone and cyclohexa-2,5-diene-1,4-diol. An important intermediate is the HO2./O2.-radical. Its rate of formation has been followed by us radiolysis using tetranitromethane as a scavenger as well as conductimetrically (build-up of H+/O2.-). The results have been interpreted. (Author)

  13. Synthesis, structural study and electrochemical properties of copper(II) complexes derived from benzene- and p-toluenesulphonylhydrazones

    OpenAIRE

    A. REGUIG; M. M. MOSTAFA; L. LARABI; Harek, Y

    2003-01-01

    The synthesis and characterization of benzene- and p-toluenesulphonylhydrazones derived from salicylaldehyde and 2-hydroxy-1-naphthaldehyde and their Cu(II) complexes are reported. The compounds were characterized on the basis of elemental analyses, electronic and IR spectra, magnetic moments, and conductance measurements. The electrochemical behavior of the Cu(II) complexes was investigated in DMSO by cyclic voltammetry (CV), rotating disc electrode (RDE) and coulometry. The oxidative polyme...

  14. Kinetics of Liquid-Phase Hydrogenation of Benzene in a Metal Hydride Slurry System Formed by M1Ni5 and Benzene

    Institute of Scientific and Technical Information of China (English)

    代世耀; 徐国华; 安越; 陈长聘; 陈立新; 王启东

    2003-01-01

    The kinetics of liquid-phase hydrogenation of benzene in misch metal nickel-five (M1Ni5) and benzene slurry system was studied by investigating the influences of the reaction temperature, pressure, alloy concentration and stirring speed on the mass transfer-reaction processes inside the slurry. The results show that the whole process is controlled by the reaction at the surface of the catalyst. The mass transfer resistance at gas-liquid interface and that from the bulk liquid phase to the surface of the catalyst particles are negligible. The apparent reaction rate is zero order for benzene concentration and first order for hydrogen concentration in the liquid phase. The kinetic model obtained fits the experimental data very well. The apparent activation energy of the hydrogen absorption reaction of M1Ni5-C6H6 slurry system is 42.16 kJ·mo1-1.

  15. Steric effects of CO2 binding to transition metal-benzene complexes: A first-principles study

    Science.gov (United States)

    Bae, Hyeonhu; Huang, Bing; Lee, Hoonkyung

    2016-09-01

    Using density functional theory (DFT) calculations, we investigated the adsorption of CO2 molecules on 3d transition metal (TM)-benzene complexes. Our calculations show that the maximum number of CO2 molecules adsorbable on Sc or Ti atoms is three, but the 18-electron rule predicts it should be four. The 18-electron rule is generally successful in predicting the maximum H2 adsorption number for TM atoms including Sc or Ti atoms. We found that the 18-electron rule fails to correctly predict CO2 binding on Sc- or Ti-benzene complexes because CO2 binding, in contrast to H2 binding, requires additional consideration for steric hindrance due to the large bond length of CO2. We calculated the occupation function for CO2 using the Tolman cone angle, which shows that three CO2 molecules fully occupy the available space around Sc- and Ti-benzene complexes. This estimation is the same maximum CO2 adsorption number predicted by DFT calculations. Therefore, we propose that the occupation function for CO2 using the Tolman cone angle is an efficient model for evaluating steric hindrance of CO2 adsorption on a surface.

  16. Eucalyptus urograndis and Pinus taeda enhance removal of chlorobenzene and benzene in sand culture: A greenhouse study.

    Science.gov (United States)

    Barcellos, Diego; Morris, Lawrence A; Nzengung, Valentine; Moura, Tiago; Mantripragada, Nehru; Thompson, Aaron

    2016-10-01

    Contamination of soils and groundwater by chlorobenzene and benzene is a common problem at industrial sites worldwide. Since chemical remediation techniques are rarely completely effective, remnants of these contaminants often persist at levels that can still influence ecosystem health. We evaluated the potential of Pinus taeda and Eucalyptus urograndis to accelerate the removal of these compounds from sand/water systems using a completely randomized block greenhouse experiment with a no-plant control. At 2-day intervals, we added a solution containing both chlorobenzene and benzene with the same concentration of 50 mg L(-1) (25 mg pot(-1)), and we monitored leachate concentrations daily. The planted treatments showed greater decrease of contaminants over time. In the absence of plants, the contaminant mass decreased 50-60% during each 2-day cycle; whereas, in the planted treatments the contaminant mass decreased 91-98%. At the end of the experiment the plant roots, leaves, and the sand-substrate each contained less than 1 mg kg(-1) of contaminants, which is ∼1% of the total contaminant mass added. In addition, we observed no tree mortality even at concentrations exceeding the aqueous solubility limit of both compounds. Our results suggest both trees are good candidates for remediating chlorobenzene and benzene in soils and groundwater. PMID:27159839

  17. Steric effects of CO2 binding to transition metal-benzene complexes: a first-principles study

    CERN Document Server

    Bae, Hyeonhu; Lee, Hoonkyung

    2016-01-01

    Using density functional theory (DFT) calculations, we investigated the adsorption of CO2 molecules on 3d transition metal (TM)-benzene complexes. Our calculations show that the maximum number of CO2 molecules adsorbable on Sc or Ti atoms is three, but the 18-electron rule predicts it should be four. The 18-electron rule is generally successful in predicting the maximum H2 adsorption number for TM atoms including Sc or Ti atoms. We found that the 18-electron rule fails to correctly predict CO2 binding on Sc- or Ti-benzene complexes because CO2 binding, in contrast to H2 binding, requires additional consideration for steric hindrance due to the large bond length of CO2. We calculated the occupation function for CO2 using the Tolman cone angle, which shows that three CO2 molecules fully occupy the available space around Sc- and Ti-benzene complexes. This estimation is the same maximum CO2 adsorption number predicted by DFT calculations. Therefore, we propose that the occupation function for CO2 using the Tolman...

  18. A Study of Gas Diffusion Electrodes for the Coupled Reaction of Water Electrolysis and Electrocatalytic Benzene Hydrogenation

    Institute of Scientific and Technical Information of China (English)

    HuangHaiyan; YuYing; WangJing

    2005-01-01

    Gas diffusion electrodes are applied to the coupled reaction of water electrolysis and electrocatalytic benzene hydrogenation. The effects of the preparation conditions of electrodes, electrolyte acidity, the concentration of benzene and water vapor, and the flow rate of N2 are investigated by evaluating the efficiency of the current. Furthermore, the optimal operational conditions have been ascertained. The results of our experiment show that gas diffusion electrodes have good performance when the content of PTFE is 10% (wt) and that of Nation is 0.75mg/cm2. The optimal operational conditions are as follows: The temperature of electrolysis is 70℃, acidity 0.5tool/L, the concentration of benzene 26%,the concentration of vapor 10%, the flow rate of N2 80mL/min-240mL/min. The efficiency of the current can reach 35% under optimal operational conditions. Then, a conclusion can be drawn that gas diffusion electrodes can improve the rate of the coupled reaction effectively.

  19. Experimental study of vortex diffusers

    Energy Technology Data Exchange (ETDEWEB)

    Shakerin, S.; Miller, P.L. [National Renewable Energy Lab., Golden, CO (United States)

    1995-11-01

    This report documents experimental research performed on vortex diffusers used in ventilation and air-conditioning systems. The main objectives of the research were (1) to study the flow characteristics of isothermal jets issuing from vortex diffusers, (2) to compare the vortex diffuser`s performance with that of a conventional diffuser, and (3) to prepare a report that disseminates the results to the designers of ventilation and air-conditioning systems. The researchers considered three diffusers: a conventional round ceiling diffuser and two different styles of vortex diffusers. Overall, the vortex diffusers create slightly more induction of ambient air in comparison to the conventional diffuser.

  20. Experimental study on terahertz radiation

    Institute of Scientific and Technical Information of China (English)

    Liying Lang(郎利影); Qirong Xing(邢岐荣); Shuxin Li(李术新); Fanglin Mao(毛方林); Lu Chai(柴路); Qingyue Wang(王清月)

    2004-01-01

    In this letter, we describe a coherent subpicosecond terahertz (THz) spectroscopy system based on nonresonant optical rectification for the generation of THz radiation. We studied the two-photon absorption (TPA) of ZnTe induced by femtosecond laser pulses via THz generation, and its influence on the generation of THz radiation. Experimental results demonstrated that the intensity of pump beam against TPA must be traded off to get an optimum generation of THz radiation. As an example, we measured absorption spectrum of water vapor by time-domain spectroscopy (TDS) in the frequency range from 0.5 to 2.5 THzwith a high overall accuracy.

  1. Thermodynamics of mixtures involving some (benzene derivatives+benzonitrile)

    International Nuclear Information System (INIS)

    Interactions of binary mixtures involving some benzene derivatives (ethylbenzene, o-, m-, p-xylene, isopropylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, and methoxybenzene) with benzonitrile were investigated in continuation of our previous studies on binary systems (benzene or toluene+benzonitrile). Heat capacities by volume unit, determined with a Picker flow calorimeter at T=298.15K, and densities, measured by using Picker vibrating densimeters at the temperatures (298.15 and 308.15)K, are reported. Measurements were made over the entire range of mole fraction. From the primary measurements, the corresponding excess quantities VE and Cp,mE are obtained. The magnitude of these experimental quantities together with HE literature data is discussed in terms of the nature and type of intermolecular interactions in binary mixtures

  2. Molecular Interactions in Binary Mixtures of Benzene with 1-Alkanols(C5,C7,C8) at 35℃:An Ultrasonic Study

    Institute of Scientific and Technical Information of China (English)

    ALI,A.; IBRAHIM.M; 等

    2003-01-01

    Densities and ultrasonic speeds have been measured in binary mixtures of benzene with 1-pentanol,1-heptanol and 1-octanol,and in the pure components,as a function of compostion at 35℃.The isentropic compressibility,intermolecular free length,relative association,acoustic impedance,isothermal compressibility,thermal expansion coefficient,deviations in isentropic compressibility,excess freee length,excess volume,deviations in ultrasonic speed,excess acoustic impedance,apparent molar compressibility,apparent molar volume,partial molar volume of 1-alkanol in benzene have been calculated from the experimental data of densities and ultrasonic speeds.The variation of these parameters with composition indicates weak interaction between the component molecules and this interaction decreases in the order:1-pentanol>1-heptanol>1-octanol.Further,theoretical values of ultrasonic speeds were evaluated using free length theory,collision factor theory,Nomoto's relation and Van Dael-Vangeel ideal mixing relation.The relative merits of these theories and relations were discussed for these systems.

  3. Vibrational characterization of the 1:1 iodine-benzene complex isolated in solid krypton.

    Science.gov (United States)

    Kiviniemi, Tiina; Hulkko, Eero; Kiljunen, Toni; Pettersson, Mika

    2008-06-12

    The structure and properties of a 1:1 iodine-benzene complex isolated in an inert krypton matrix at low temperature have been studied with infrared and resonance Raman spectroscopy and with MP2 calculations. The structure of the ground-state complex is found to be unsymmetric, and the I-I vibrational frequency is found to be red-shifted by 3.94 cm(-1) upon complexation. The experimental data agree well with computational results, leading to the conclusion that the I2-Bz complex structure is not axial but of above-bond type, identically with other halogen-benzene complexes. PMID:18489172

  4. Ionic Liquid Catalyst Used in Deep Desulfuration of the Coking Benzene for Producing Sulfurless Benzene

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xia-Ping; WANG Yan-Liang; MENG Fan-Wei; FAN Xing-Ming; QIN Song-Bo

    2008-01-01

    For the widening need of benzene used in organic synthesis, ionic liquid catalyst was prepared to study the process of deep desulfuration in the coking benzene. The result shows that the effect of de-thiophene by the ionic liquid catalyst (N-methyl imidazolium hydrogen sulfate [Hmim][HSO4]) is related to its acid function value.Hammett indicator was used to determine the acid function value H0 of the ionic liquid. It can be concluded that while the acid function value is in the range from -4 to -12, the ionic liquid catalyst can make the concentration certain acid quantity and strength, the ionic liquid catalyst helps to form alkyl thiophene through Friedel-Crafts reaction, which differs from the character of benzene and it is absolutely necessary for the separation and refinement of benzene. But overabundant quantity and higher acid value of [Hmim][HSO4] are more suitable for the side copolymerization of benzene, thiophene and alkene, thereby affecting repeated use of the ionic liquid catalyst([Hmim][HSO4]). In our research, thiophene derivant produced by desulfurization in the coking benzene was used as the polymer to provide the passing channel of the charges. The ionic liquid composition in poor performance after repeated use was made to prepare conductive material (resisting to static electricity) as an "electron-receiving" and "electron-giving" doping agent. The result shows that thiophene derivant after desulfuration in the coking benzene can be used to prepare doping conductive materials.

  5. Economical benzene emission reduction

    International Nuclear Information System (INIS)

    Benzene has been classified as a toxic compound under the Canadian Environmental Protection Act. This has prompted the Alberta Energy and Utilities Board (AEUB) to introduce specific reporting and monitoring guidelines for the oil and gas industry regarding excessive benzene emissions. Glycol dehydration units have been determined to be the major single source of benzene emissions causing air and soil pollution. DualTank Corp. has designed a condensation and storage tank unit to enhance emission reduction, odour elimination and liquid recovery from dehydration units. Their newly designed combined tank unit consists of a large, uninsulated surface area for cooling, and an excessive internal volume for increased retention time. The first prototype was installed in December 1998 at an Enerplus Resources Site. The system provides excellent benzene emission reduction and the elimination of odours and visual plumes. Effective January 1, 1999, the petroleum and natural gas industry must either clean up excessive emissions voluntarily or face government imposed regulations, facility shutdowns and/or fines. 1 fig

  6. Molecular dynamics simulation of benzene

    Science.gov (United States)

    Trumpakaj, Zygmunt; Linde, Bogumił B. J.

    2016-03-01

    Intermolecular potentials and a few models of intermolecular interaction in liquid benzene are tested by Molecular Dynamics (MD) simulations. The repulsive part of the Lennard-Jones 12-6 (LJ 12-6) potential is too hard, which yields incorrect results. The exp-6 potential with a too hard repulsive term is also often used. Therefore, we took an expa-6 potential with a small Gaussian correction plus electrostatic interactions. This allows to modify the curvature of the potential. The MD simulations are carried out in the temperature range 280-352 K under normal pressure and at experimental density. The Rayleigh scattering of depolarized light is used for comparison. The results of MD simulations are comparable with the experimental values.

  7. Dynamic Kerr effect study on six-membered-ring molecular liquids: benzene, 1,3-cyclohexadiene, 1,4-cyclohexadiene, cyclohexene, and cyclohexane.

    Science.gov (United States)

    Kakinuma, Shohei; Shirota, Hideaki

    2015-04-01

    The intermolecular dynamics of five six-membered-ring molecular liquids having different aromaticities-benzene, 1,3-cyclohexadiene, 1,4-cyclohexadiene, cyclohexene, and cyclohexane-measured by femtosecond Raman-induced Kerr effect spectroscopy have been compared in this study. The line shapes of the Fourier transform low-frequency spectra, which arise from the intermolecular vibrational dynamics, are trapezoidal for benzene and 1,3-cyclohexadiene, triangular for 1,4-cyclohexadiene and cyclohexene, and monomodal for cyclohexane. The trapezoidal shapes of the low-frequency spectra of benzene and 1,3-cyclohexadiene are due to the librational motions of their aromatic planar structures, which cause damped nuclear response features. The time integrals of the nuclear responses of the five liquids correlate to the squares of the polarizability anisotropies of the molecules calculated on the basis of density functional theory. The first moments of the low-frequency spectra roughly linearly correlate to the bulk parameters of the square roots of the surface tensions divided by the densities and the square roots of the surface tensions divided by the molecular weights, but the plots for cyclohexene deviate slightly from the correlations. The picosecond overdamped transients of the liquids are well fitted by a biexponential function. The fast time constants of all of the liquids are approximately 1.1-1.4 ps, and they do not obey the Stokes-Einstein-Debye hydrodynamic model. On the other hand, the slow time constants are roughly linearly proportional to the products of the shear viscosities and the molar volumes. The observed intramolecular vibrational modes at less than 700 cm(-1) for all of the liquids are also assigned on the basis of quantum chemistry calculations. PMID:25741755

  8. Evaluation of seawater contamination with benzene, toluene and xylene in the Ubatuba north coast, SP region, and study of their removal by ionizing radiation; Avaliacao da contaminacao da agua do mar por benzeno, tolueno e xileno na regiao de Ubatuba, litoral norte (SP) e estudo da degradacao destes compostos por radiacao ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Kelly Cristina Santana de

    2006-07-01

    A major concern with leaking petroleum is the environmental contamination by the toxic and low water-soluble components such as benzene, toluene, and xylenes (BTX). These hydrocarbons have relatively high pollution potential because of their significant toxicity. The objective of this study was to evaluate the contamination of seawater by the main pollutants of the output and transport of petroleum, such as benzene, toluene, and xylene, and their removal by the exposure to the ionizing radiation. The studied region was Ubatuba region, SP, between 23 deg 26'S and 23 deg 46'S of latitude and 45 deg 02'W and 45 deg 11'W of longitude, area of carry and output of petroleum, and samples were collected from November, 2003 to July, 2005. For BTX in seawater analysis, the Purge and Trap concentrator with FIDGC detector showed significantly higher sensibility than Head Space concentrator with MSGC detector. The minimal detected limits (MDL) obtained at FIDGC were of 0.50 {mu}g/L for benzene, 0.70 {mu}g/L for toluene, and 1.54 {mu}g/L for xylene, and the obtained experimental variability was 15%. While the concentrator type Headspace system with MS detector showed higher MLD, about of 9.30 mg/L for benzene, 8.50 mg/L for toluene, and 9.80 mg/L for xylene, and 10% of experimental variability. In the studied area the benzene concentration varied from 1.0 {mu}g/L to 2.0 {mu}g/L, the concentration of toluene varied from < 0.70 {mu}g/L to 3.24 {mu}g/L and the maximum value of xylene observed was of 2.92 {mu}g/L. The seawater samples contaminated with BTX standard and exposed to ionizing radiation using a source of {sup 60}Co, presented a removal from 10% to 40% of benzene at 20 kGy absorbed doses and concentration of 35.1 mg/L and 70.2 mg/L, respectively; from 20% to 60% of toluene removal with 15 kGy absorbed dose and from 20% to 80% of xylene with 15 kGy absorbed dose in similar concentrations. (author)

  9. Compressibility and volumetric studies of polyethylene-glycols in aqueous, methanolic, and benzene solutions at T=298.15K

    International Nuclear Information System (INIS)

    The speed of sound and density measurements in water, methanol, and benzene solutions for the solutes PEG-400, PEG-1000, and PEG-4000 at T=298.15K (0.05 to 0.5mol.kg-1) are reported. The data obtained are used to calculate thermodynamic parameters such as adiabatic (isentropic) compressibility of solutions (βad), apparent molar volume (φV) and apparent molar compressibility (φK) for solute molecules in all the solvent media. The limiting partial molar volume (φVo) and limiting partial molar compressibility (φKo) of solute molecules are used to estimate volume of transfer and compressibility of transfer for PEG molecules from methanol to aqueous and benzene to aqueous media. The high observed negative (φKo) values in methanol are interpreted in terms of breakdown of one-dimensional H-bonded structure of methanolic molecules. The (φKo) values observed in water although negative but of small magnitude as compared to salts in water. Attempt is made to estimate hydration number for these molecules in aqueous solutions by applying Shiio's method and it is observed that PEG-4000 is hydrated most. These results are discussed in terms of solute-solvent and hydrophobic interactions and effects due to conformational characteristic of high molecular weight glycol molecules

  10. Electrochemical Studies of 1,4-Bis[2-(2-pyridyl)-vinyl] Benzene and 1,4-Bis[2-(4-pyridyl) vinyl] Benzene Laser Dyes via Cyclic Voltammetry, Convolutive Voltammetry and Digital Simulation Methods

    Institute of Scientific and Technical Information of China (English)

    EL-DALY, Samy A; EL-HALLAG,Ibrahirn S; EBEED, Ezeiny M; GHONEIM, Mohamed M

    2009-01-01

    Electrochemical properties of two diolefinic laser dyes namely 1,4-bis[2-(2-pyddyl)-vinyl] benzene (2PVB) and 1,4-bis[2-(4-pyridyl) vinyl] benzene (4PVB) have been investigated using cyclic voltammetry and convolutive voltammetry combined with digital simulation at a platinum electrode in 0.1 mol/L tetrabutyl ammonium perchlo-rate (TBAP) in the two different solvents acetonitrile (CH3CN) and dimethylformamide (DMF). The species were reduced via consumption of two sequential electrons to form radical anion and dianion. In switching the potential to positive direction, the two compounds were oxidized by loss of one electron, which was followed by a fast isomeri-sation process. The electrode reaction pathway and the electrochemical parameters of the investigated compounds were determined using cyclic voltammetry. The extracted electrochemical parameters were verified and confirmed via digital simulation and convolutive voltammetry methods.

  11. On the mechanistic differences of benzene-induced leukemogenesis between wild type and p53 knockout mice

    International Nuclear Information System (INIS)

    Leukemia induction by benzene inhalation was first reported by Le Noire in 1887, described multiple cases of leukemia among Parisian cobblers. However, experimental induction of leukemia by benzene exposure was not succeeded for a hundred years, until Snyder et al. and our group reported it nearly 20 years ago. Nevertheless, the mechanistic background of benzene-induced leukemia was still an enigma until recently a benzene-induced peculiar cell kinetics of the stem/progenitor cells has been elucidated by our study, demonstrated a marked repeated oscillatory decrease in peripheral blood and bone marrow (BM) cellularity during and after benzene exposure, which epigenetically preceded and developed the leukemia more than a year later. We utilized the BUUV (bromodeoxyuridine + UV exposure) method to study stem/progenitor cell kinetics during and/or after benzene exposure. Using these methods, we were able to measure the labeling rate, cycling fraction of clonogenic progenitor cells, and other cell cycle parameters. The cycling fraction of stem/progenitor cells was found not to turn into an active hematopoiesis but to remain low during benzene inhalation and further we found evidence that the cycling fraction depression may be mediated in part by a slowing of stem/progenitor cell cycling perse by up-regulation of p21. The benzene induced leukemogenicity between mice carrying wild-type p53 and mice lacking p53 seem to differ from one another. In the case of p53 knockout mouse, DNA damage such as weak mutagenicity and or chromosomal damages are retained, and those damages participated in the induction of a consequent activation of proto-oncogenes and the like, which led cells to further neoplastic changes. In contrast, in the case of wild type mice, a dramatic oscillational change in the cell cycle of the stem cell compartment seems to be an important factor for mice carrying the p53 gene. (author)

  12. Experimental Studies in Ice Nucleation

    Science.gov (United States)

    Wright, Timothy Peter

    Ice nuclei play a critical role in the formation of precipitation in mixed phase clouds. Modification of IN concentrations can lead to changes in cloud lifetimes and precipitation size. Presented in this study are experimental investigations into ice nuclei in an ongoing effort to reduce the uncertainties that ice nuclei have on cloud processes and climate. This research presents a new version of the cold stage drop freezing assay to investigate the time-dependence of heterogeneous nucleation. The temperature range for the instrument spans from the melting point of water to the homogeneous freezing limit of ˜-38 deg C. Temperature stability for the instrument allowed for experimental operation for up to four days while interrogating the same sample. Up to a one hundred fold increase in the number of analyzed drops was accomplished through an in-house written automated drop freezing detection software package. Combined instrument design improvements allow for the analysis of IN concentrations down to ˜10-8 ice nuclei per picoliter of sample water. A new variant of the multiple-component stochastic model for heterogeneous ice nucleation was used to investigate the time dependence of heterogeneous freezing processes. This was accomplished by analyzing how the changes in the cooling rate can impact the observed nucleation rate. The model employed four material-dependent parameters to accurately capture the observed freezing of water drops containing Arizona Test Dust. The parameters were then used to accurately predict the freezing behavior of the drops in time dependent experiments. The time dependence freezing of a wide range of materials was then investigated. These materials included the minerals montmorillonite and kaolinite, the biological proxy ice nuclei contained within the product Icemax, and flame soot generated from the incomplete combustion of ethylene gas. The time dependence for ice nuclei collected from rainwater samples was also investigated. The

  13. FTIR study of the photocatalytic degradation of gaseous benzene over UV-irradiated TiO2 nanoballs synthesized by hydrothermal treatment in alkaline solution

    International Nuclear Information System (INIS)

    In this study, photocatalysts of TiO2 nanoballs were obtained via a hydrothermal treating of commercial P25 in alkaline solution, and then characterized with SEM, XRD, BET and surface photovoltage spectroscopy techniques. The UV-assisted photodegradation of gaseous benzene over P25 and the prepared TiO2 nanoballs was monitored by an in situ infrared technique. The results demonstrated that the prepared TiO2 nanoballs in anatase form were more active than commercial P25 in photocatalytic oxidation of gaseous benzene. The promoted activity of the hydrothermal-treated TiO2 is attributed to the increasing specific surface area and larger band gap induced by the reduced crystallite size. The spectra of FTIR indicated that weakly adsorbed phenol was formed as the reaction progress. Hydroxyl groups on the surface of TiO2 nanoballs are able to react with photo-produced phenol, which is then retained on the catalyst surface leading to the progressive deactivation of the catalyst in the gas-solid system.

  14. Effect of methoxy or benzyloxy groups bound to an amino-benzene donor unit for various nonlinear optical chromophores as studied by hyper-Rayleigh scattering

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Toshiki, E-mail: toshiki@nict.go.jp [Advanced ICT Research Institute, National Institute of Information and Communications Technology, 588-2 Iwaoka, Kobe 651-2492 (Japan); Aoki, Isao; Miki, Hideki; Yamada, Chiyumi; Otomo, Akira [Advanced ICT Research Institute, National Institute of Information and Communications Technology, 588-2 Iwaoka, Kobe 651-2492 (Japan)

    2013-05-15

    We report the molecular first hyperpolarizability (β) of a series of nonlinear optical (NLO) chromophores comprising amino-benzene with an additional methoxy or benzyloxy group as the donor units, polyene, phenyl-di-vinylene, or thienyl-di-vinylene as the π-electron bridges, and 2-(dicyanomethylene)-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran (TCF), 2-(dicyanomethylene)-3-cyano-4,5-dimethyl-5-trifluoromethyl-2, 5-dihydrofuran (CF{sub 3}–TCF) or 2-(dicyanomethylene)-3-cyano-4-methyl-5-phenyl-5-trifluoromethyl-2, 5-dihydrofuran (CF{sub 3}–phenyl–TCF) as the acceptor units. An improvement in linear and nonlinear optical properties was found in the long π-conjugated NLO chromophores with methoxy or benzyloxy groups compared with benchmark chromophores without these groups. We also discuss a possible mechanism with a contribution for improvement, that is, intra-molecular hydrogen bonding. Highlights: ► We report the molecular first hyperpolarizability of a series of NLO chromophores. ► Effect of methoxy or benzyloxy group bound to amino-benzene donor unit was studied. ► Improvements in NLO properties were found for the modified NLO chromophores. ► Intra-molecular hydrogen bonding as a mechanism for the improvement was proposed. ► We found an important area of progress in the design of NLO chromophores.

  15. Effect of methoxy or benzyloxy groups bound to an amino-benzene donor unit for various nonlinear optical chromophores as studied by hyper-Rayleigh scattering

    International Nuclear Information System (INIS)

    We report the molecular first hyperpolarizability (β) of a series of nonlinear optical (NLO) chromophores comprising amino-benzene with an additional methoxy or benzyloxy group as the donor units, polyene, phenyl-di-vinylene, or thienyl-di-vinylene as the π-electron bridges, and 2-(dicyanomethylene)-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran (TCF), 2-(dicyanomethylene)-3-cyano-4,5-dimethyl-5-trifluoromethyl-2, 5-dihydrofuran (CF3–TCF) or 2-(dicyanomethylene)-3-cyano-4-methyl-5-phenyl-5-trifluoromethyl-2, 5-dihydrofuran (CF3–phenyl–TCF) as the acceptor units. An improvement in linear and nonlinear optical properties was found in the long π-conjugated NLO chromophores with methoxy or benzyloxy groups compared with benchmark chromophores without these groups. We also discuss a possible mechanism with a contribution for improvement, that is, intra-molecular hydrogen bonding. Highlights: ► We report the molecular first hyperpolarizability of a series of NLO chromophores. ► Effect of methoxy or benzyloxy group bound to amino-benzene donor unit was studied. ► Improvements in NLO properties were found for the modified NLO chromophores. ► Intra-molecular hydrogen bonding as a mechanism for the improvement was proposed. ► We found an important area of progress in the design of NLO chromophores

  16. Thermodynamic study of sorption processes of gaseous benzene and water on metal–organic framework [Zn4(dmf)(ur)2(ndc)4

    International Nuclear Information System (INIS)

    Highlights: • Pressure of guests was measured in systems host (Zn4(dmf)(ur)2(ndc)4) – guests (benzene, water). • The volatilities of guests and thermodynamic values of desorption processes were obtained. • Gibbs energy change in the process of bonding of liquid guest by the framework was calculated. • Several energy-different states of guests in [Zn4(dmf)(ur)2(ndc)4] were revealed. -- Abstract: The pressure of guests was measured by the static method with glass membrane-gauge manometers in the systems host (metal–organic framework [Zn4(dmf)(ur)2(ndc)4]) – guests (benzene, water) within the temperature range 316 K to 470 K. As a result of this study the thermal stability of investigated systems were established, the temperature dependences of pressure for evaporation processes and the composition of the gas phase were obtained, enthalpies and entropies of desorption were determined, Gibbs energy change in the process of bonding of liquid guest by the framework was calculated. On the base of this information the conclusions about the nature of the interactions between host and guest molecules were made. The adsorption properties of the polymer have been investigated by the isopiestic method

  17. Study on serum metabonomics of rats exposed to low-dose ionizing radiation, carbon monoxide, benzene and noise

    Directory of Open Access Journals (Sweden)

    Qing-rong WANG

    2015-07-01

    Full Text Available Objective To investigate the combined effects of low-dose ionizing radiation, carbon monoxide, benzene and noise on serum metabolites and the mechanism of injury induced by these complex environmental factors in rats. Methods  Sixteen adult SD rats were randomly divided into control group and exposed group (8 each. The exposed group received the combined effect every day for 7 days. At the end of experiment, sera were collected from the abdominal aorta of rats. The metabolic fingerprint of serum was obtained by 1H nuclear magnetic resonance (1H NMR spectroscopy and determined with pattern recognition techniques of principal component analysis (PCA and orthogonal signal correction-partial least squares (OSC-PLS. The similarities and differences in metabolic profiles between two groups were visualized by SIMCA-P software. Results The rat serum 1H NMR spectra revealed different metabolic spectra between the control group and exposed group. The OSC-PLS plots of the serum samples presented respectively marked clustering between the two groups. Compared with the control group, the contents of lipid, high density lipoprotein, glycine/glucose, N-acetyl glycoprotein 1, N-acetyl glycoprotein 2, phosphatidyl choline and unsaturated fatty acid increased, while those of lactic acid, threonine/lipid, alanine, creatine, glycerylphosphorylcholine/ trimethylamine oxide, low density lipoprotein/high density lipoprotein, low density lipoprotein, very low density lipoprotein/ low density lipoprotein, very low density lipoprotein and saturated fatty acid decreased. Conclusions Combination of low-dose ionizing radiation, carbon monoxide, benzene and noise could induce changes of serum metabolites in rats, involving in immune function, renal function and energy metabolism. The NMR-based-metabonomics method has potential of application in research on combined biological effects of the complex environmental factors. DOI: 10.11855/j.issn.0577-7402.2015.07.09

  18. Hydrogenation of single-wall carbon nanotubes using polyamine reagents: combined experimental and theoretical study.

    Science.gov (United States)

    Miller, Glen P; Kintigh, Jeremy; Kim, Eunja; Weck, Philippe F; Berber, Savas; Tomanek, David

    2008-02-20

    We combine experimental observations with ab initio calculations to study the reversible hydrogenation of single-wall carbon nanotubes using high boiling polyamines as hydrogenation reagents. Our calculations characterize the nature of the adsorption bond and identify preferential adsorption geometries at different coverages. We find the barrier for sigmatropic rearrangement of chemisorbed hydrogen atoms to be approximately 1 eV, thus facilitating surface diffusion and formation of energetically favored, axially aligned adsorbate chains. Chemisorbed hydrogen modifies the structure and stability of nanotubes significantly and increases the inter-tube distance, thus explaining the improved dispersability in solvents like methanol, ethanol, chloroform, and benzene. PMID:18220395

  19. Decreased levels of CXC-chemokines in serum of benzene-exposed workers identified by array-based proteomics

    OpenAIRE

    Vermeulen, Roel; Lan, Qing; Zhang, Luoping; Gunn, Laura; McCarthy, Diane; Woodbury, Ronald L; McGuire, Marielena; Podust, Vladimir N.; Li, Guilan; Chatterjee, Nilanjan; Mu, Ruidong; Yin, Songnian; Rothman, Nathaniel; Smith, Martyn T.

    2005-01-01

    Benzene is an important industrial chemical and environmental contaminant that causes leukemia. To obtain mechanistic insight into benzene's mechanism of action, we examined the impact of benzene on the human serum proteome in a study of exposed healthy shoe-factory workers and unexposed controls. Two sequential studies were performed, each using sera from 10 workers exposed to benzene (overall mean benzene air level >30 ppm) and 10 controls. Serum samples were subjected to anion-exchange fra...

  20. Dehydrogenation of benzene on Pt(111) surface

    Science.gov (United States)

    Gao, W.; Zheng, W. T.; Jiang, Q.

    2008-10-01

    The dehydrogenation of benzene on Pt(111) surface is studied by ab initio density functional theory. The minimum energy pathways for benzene dehydrogenation are found with the nudge elastic band method including several factors of the associated barriers, reactive energies, intermediates, and transient states. The results show that there are two possible parallel minimum energy pathways on the Pt(111) surface. Moreover, the tilting angle of the H atom in benzene can be taken as an index for the actual barrier of dehydrogenation. In addition, the properties of dehydrogenation radicals on the Pt(111) surface are explored through their adsorption energy, adsorption geometry, and electronic structure on the surface. The vibrational frequencies of the dehydrogenation radicals derived from the calculations are in agreement with literature data.

  1. Benzene vapor recovery and processing

    International Nuclear Information System (INIS)

    The National Emissions Standards for Hazardous Air Pollutants, or NESHAPs, have provided a powerful motivation for interest in, and attention to, benzene vapor emissions in recent times. Benzene and its related aromatics are volatile organic compounds (VOCs), which marks them for surveillance as potential contributors to air pollution. In addition, benzene is a suspected carcinogen, which applies a special urgency to its control. The regulations governing the control of benzene emissions were issued as Title 40, Code of Federal Regulations, Part 61, subpart Y (Storage Vessels); subpart BB (Transfer Operations); and subpart FF (Waste Operations). These regulations specify very particular emission reduction guidelines for various generating sources. The problem in the hydrocarbon processing industry is to identify significant sources of benzene vapors in plants, and then to collect and process these vapors in an environmentally acceptable manner. This paper discusses various methods for collecting benzene fumes in these facilities

  2. Spectroscopic studies, fluorescence quenching by molecular oxygen and amplified spontaneous emission of 1,4-bis [2-(2-pyridyl) vinyl] benzene (P2VB) diolefinic laser dye

    Science.gov (United States)

    El-Daly, Samy A.; Ebeid, E. M.

    2014-04-01

    The UV-visible electronic absorption spectra, molar absorptivity, fluorescence spectra, fluorescence quantum yield and excited state lifetime of 1,4-bis [2-(2-pyridyl) vinyl] benzene P2VB were measured in different solvents. The fluorescence quenching of P2VB by molecular oxygen was also studied using lifetime measurements. A 2 × 10-4 mol dm-3 solution of P2VB in dimethyl formamide (DMF) gave amplified spontaneous emission (ASE) in blue spectral region with emission maximum at 420 nm upon pumping by 337.1 nitrogen laser pulse. The photochemical quantum yields (ϕc) of trans-cis photoisomerization of P2VB were calculated in different organic solvents. The photoreactivity of P2VB are also studied PMMA matrix.

  3. A density functional study of inhibition of the HDS hydrogenation pathway by pyridine, benzene, and H2S on MoS2-based catalysts

    DEFF Research Database (Denmark)

    Logadottir, A.; Moses, Poul Georg; Hinnemann, Berit; Topsøe, N.-Y.; Topsøe, H.; Nørskov, Jens Kehlet

    interaction of pyridine with the two types of edges of MoS2 catalyst nanoparticles, Particular attention is given to Studies of the hydrogenation (HYD) pathway in HDS since this is the favored pathway for refractory sulfur compounds and it is the pathway, which is most severely poisoned by basic nitrogen......The inhibition of catalytic hydrodesulfurization (HDS) by basic nitrogen compounds is an important problem it) the production of ultra low sulfur transportation fuels and the origin of the inhibition effects is presently elucidated by performing density functional theory (DFT) calculations on the...... compounds. In order to understand the observed inhibitor trends. DFT studies oil (lie adsorption of benzene which is a weaker poison than pyridine, and H2S, which has no or only a very minor influence on the HYD pathway. have also been made, We find that the adsorption of pyridine is quite strong and...

  4. Experimental studies of sewer exfiltration.

    Science.gov (United States)

    Ellis, J B; Revitt, D M; Lister, P; Willgress, C; Buckley, A

    2003-01-01

    The effects of joint openings and in-pipe sediment on exfiltration losses in an experimental sewer are reported and the influence of flow and head on loss rates are also evaluated. Exfiltration rates tend to be exponential with changes in head for clean-water tests but exhibit power functions when the pipe is subject to sedimentation. In-pipe sediment leads to an effective sealing of joints especially if the invert deposits are both organic in nature and contain saturated adhesive material such as shredded toilet tissue. Simple tracer techniques are described to quantify exfiltration losses and the potential effects of tracer adsorption by pipe solids are evaluated. PMID:12666802

  5. Benzene exposures in urban areas

    International Nuclear Information System (INIS)

    Benzene exposures in urban areas were reviewed. Available data confirm that both in USA and Europe, benzene concentrations measured by fixed outdoor monitoring stations underestimate personal exposures of urban residents. Indoor sources, passive smoke and the high exposures during commuting time may explain this difference. Measures in European towns confirm that very frequently mean daily personal exposures to benzene exceed 10 μg/m3, current European air quality guideline for this carcinogenic compound

  6. Biomarkers of environmental benzene exposure.

    OpenAIRE

    Weisel, C; Yu, R; Roy, A; Georgopoulos, P.

    1996-01-01

    Environmental exposures to benzene result in increases in body burden that are reflected in various biomarkers of exposure, including benzene in exhaled breath, benzene in blood and urinary trans-trans-muconic acid and S-phenylmercapturic acid. A review of the literature indicates that these biomarkers can be used to distinguish populations with different levels of exposure (such as smokers from nonsmokers and occupationally exposed from environmentally exposed populations) and to determine d...

  7. Benzene as a Chemical Hazard in Processed Foods

    Directory of Open Access Journals (Sweden)

    Vânia Paula Salviano dos Santos

    2015-01-01

    Full Text Available This paper presents a literature review on benzene in foods, including toxicological aspects, occurrence, formation mechanisms, and mitigation measures and analyzes data reporting benzene levels in foods. Benzene is recognized by the IARC (International Agency for Research on Cancer as carcinogenic to humans, and its presence in foods has been attributed to various potential sources: packaging, storage environment, contaminated drinking water, cooking processes, irradiation processes, and degradation of food preservatives such as benzoates. Since there are no specific limits for benzene levels in beverages and food in general studies have adopted references for drinking water in a range from 1–10 ppb. The presence of benzene has been reported in various food/beverage substances with soft drinks often reported in the literature. Although the analyses reported low levels of benzene in most of the samples studied, some exceeded permissible limits. The available data on dietary exposure to benzene is minimal from the viewpoint of public health. Often benzene levels were low as to be considered negligible and not a consumer health risk, but there is still a need of more studies for a better understanding of their effects on human health through the ingestion of contaminated food.

  8. Study on enrichment of film to low concentration benzene%膜对低浓度苯富集技术研究

    Institute of Scientific and Technical Information of China (English)

    滑迎辉; 郝瑞建; 祝维燕; 艾长波

    2012-01-01

    本文用扫描电镜对CSM膜进行结构表征,照片显示出膜表面均匀平整,膜与支撑层结合紧密,增强了膜的强度和稳定性.利用CSM膜对C6H6/空气体系进行富集.考察了原料气浓度、原料气流量、渗透侧压力和操作温度对富集效果的影响.实验结果表明:随着原料气中苯浓度的增加,富集率先增大后减小;随着原料气流量的增加,富集率明显降低;随着真空度的增大,富集率明显增大;温度对富集率的影响不大.当原料气操作温度为293.2K、苯的浓度为40× 10-6、渗透侧压力0.067MPa、流量为150L·h-1时,CSM膜对低浓度苯的富集效率可达25%.%CSM membranes were characterized by SEM. The photo showed smooth surface, tight combination of membrane and supporting layer, which enhanced the strength and stability of membrane. The enrichment of CSM to C6H6/air system was studied. The effect of concentration and flow of feed gas, osmosis lateral pressure and temperature to enrichment were investigated. The results showed that the enrichment rate increased first and decreased after with the concentration of benzene raised. The enrichment rate decreased with flow of feed gas raised. The enrichment rate increased with vacuity raised. The temperature affected little. The enrichment of CSM membrane to low concentration benzene reached 25% when temperature was 293.2K, the concentration of benzene was 40x10-6, osmosis lateral pressure was 0.067MPa, the flow is 150L·h-1.

  9. Differences in the pathways for metabolism of benzene in rats and mice simulated by a physiological model.

    OpenAIRE

    Medinsky, M A; Sabourin, P J; Henderson, R F; Lucier, G; Birnbaum, L S

    1989-01-01

    Studies conducted by the National Toxicology Program on the chronic toxicity of benzene indicated that B6C3F1 mice were more sensitive to the carcinogenic effects of benzene than were F344 rats. A physiological model was developed to describe the uptake and metabolism of benzene in rats and mice. Our objective was to determine if differences in toxic effects could be explained by differences in pathways for benzene metabolism or by differences in total uptake of benzene. Compartments incorpor...

  10. How the sorption of benzene in soils contaminated with aromatic hydrocarbons is affected by the presence of biofuels

    Directory of Open Access Journals (Sweden)

    Maria Manuela Carvalho

    2015-04-01

    Full Text Available The increasing use of biofuels as additives to gasoline may have potential indirect effects on the efficiency of soil remediation technologies used to remediate fuel spills. This problem has not yet been studied. Sorption is one of the controlling processes in soil remediation. The effect of biofuels on sorption and phase distribution of contaminants by different natural soils has not been reported on the literature. The present work examines how two different biofuels, n-butanol and soybean biodiesel, affect benzene sorption in two naturally occurring subsoils (granite and limestone. Sorption isotherms were made with soils deliberately contaminated with benzene, benzene and n-butanol and benzene plus biodiesel, using lab-scale reactors operated at constant temperature, each one loaded with 700 grams of wet sterilized soil. For each type of soil, five isotherms were determined corresponding to different contamination profiles. It was concluded that sorption was strongly affected by the nature of the soil. The partition of benzene into the different phases of the soil was significantly affected by the presence of biofuels. The experimental data was fitted to conventional sorption models, Freundlich, Langmuir and a second order polynomial. Model parameters were determined using a non-linear least squares (NLLS optimization algorithm and showed a good agreement between experimental and fitted data.

  11. The excited state antiaromatic benzene ring: a molecular Mr Hyde?

    Science.gov (United States)

    Papadakis, Raffaello; Ottosson, Henrik

    2015-09-21

    The antiaromatic character of benzene in its first ππ* excited triplet state (T1) was deduced more than four decades ago by Baird using perturbation molecular orbital (PMO) theory [J. Am. Chem. Soc. 1972, 94, 4941], and since then it has been confirmed through a range of high-level quantum chemical calculations. With focus on benzene we now first review theoretical and computational studies that examine and confirm Baird's rule on reversal in the electron count for aromaticity and antiaromaticity of annulenes in their lowest triplet states as compared to Hückel's rule for the ground state (S0). We also note that the rule according to quantum chemical calculations can be extended to the lowest singlet excited state (S1) of benzene. Importantly, Baird, as well as Aihara [Bull. Chem. Soc. Jpn. 1978, 51, 1788], early put forth that the destabilization and excited state antiaromaticity of the benzene ring should be reflected in its photochemical reactivity, yet, today these conclusions are often overlooked. Thus, in the second part of the article we review photochemical reactions of a series of benzene derivatives that to various extents should stem from the excited state antiaromatic character of the benzene ring. We argue that benzene can be viewed as a molecular "Dr Jekyll and Mr Hyde" with its largely unknown excited state antiaromaticity representing its "Mr Hyde" character. The recognition of the "Jekyll and Hyde" split personality feature of the benzene ring can likely be useful in a range of different areas. PMID:25960203

  12. Toxicogenomic analysis of gene expression changes in rat liver after a 28-day oral benzene exposure

    NARCIS (Netherlands)

    Heijne, W.H.M.; Jonker, D.; Stierum, R.H.; Ommen, B. van; Groten, J.P.

    2005-01-01

    Benzene is an industrial chemical, component of automobile exhaust and cigarette smoke. After hepatic bioactivation benzene induces bone marrow, blood and hepatic toxicity. Using a toxicogenomics approach this study analysed the effects of benzene at three dose levels on gene expression in the liver

  13. CREATIVE DISCLOSURE: AN EXPERIMENTAL STUDY

    OpenAIRE

    Cuzdriorean Dan Dacian; Vladu Alina Beattrice

    2012-01-01

    This empirical study extends the study conducted by Vladu, Grosanu and Cuzdriorean (2012) and reached similar conclusions. This particular research was conducted with the scope of assessing the impact of: positive bias, persuasive language, creative visual manipulation and performance comparisons over the unsophisticated users of accounting opinion. We have chosen this particular category since retail investors have been identified as relying on the information provided in corporate annual re...

  14. Studies of Experimental Bacterial Translocation

    OpenAIRE

    Stenbäck, Anders

    2005-01-01

    One of the main obstacles to maintaining patients with short bowel syndrome on parenteral nutrition, or successfully transplanting these patients with a small bowel graft, is the many severe infections that occur. Evidence is accumulating that translocating bacteria from the patient’s bowel causes a significant part of these infections. In this thesis bacterial translocation is studied in a Thiry-Vella loop of defunctionalised small bowel in the rat. Bacterial translocation to the mesenteric ...

  15. In-situ Investigation of BBr_3/benzene Solution by Fourier Transformation Infrared Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    YU Li-li; GAI Li-gang; CUI De-Hang; WANG Qi-long

    2009-01-01

    By means of the in-situ Fourier transformation infrared spectroscopy(FTIR), the properties of BBr_3/ benzene solution, which is usually used as the reactant and solution to synthesize BN by benzene-thermal method, have been investigated. The results show that there are some side reactions between BBr_3 and benzene: (1) BBr_3 as an electron-deficient molecule reacts with benzene at room temperature; (2) below 100℃, substitution of Br atom for H atom of benzene(ring-H) dominates in BBr_3/benzene solution; (3) cracking of benzene ring occurs at a temperature above 100℃; (4) decomposition of benzene molecules and formation of long-chain aliphatic compounds feature the spectra of BBr_3/benzene solution collected at above 160℃. They are unfavor for BN to form when BBr_3 is excessive in the synthesis of BN by benzene-thermal route. On the basis of the experimental results, a coordination reaction mechanism via a η~2-C_6H_6 binding mode in BBr_3/benzene solution is suggested.

  16. Experimental studies of neutrino oscillations

    CERN Document Server

    Kajita, Takaaki

    2016-01-01

    The 2015 Nobel Prize in physics has been awarded to Takaaki Kajita and Arthur McDonald "for the discovery of neutrino oscillations, which shows that neutrinos have mass". Takaaki Kajita of Tokyo University is a Japanese physicist, known for neutrino experiments at the Kamiokande and its successor, Super-Kamiokande. This volume of collected works of Kajita on neutrino oscillations provides a good glimpse into as well as a record of the rise and the role of Asian research in the frontiers of neutrino physics. Japan is now a major force in the study of the 3 families of neutrinos. Much remains to be done to clarify the Dirac vs. Majorana nature of the neutrino, and the cosmological implications of the neutrino. The collected works of Kajita and his Super-Kamiokande group will leave an indelible foot-print in the history of big and better science.

  17. CREATIVE DISCLOSURE: AN EXPERIMENTAL STUDY

    Directory of Open Access Journals (Sweden)

    Cuzdriorean Dan Dacian

    2012-07-01

    Full Text Available This empirical study extends the study conducted by Vladu, Grosanu and Cuzdriorean (2012 and reached similar conclusions. This particular research was conducted with the scope of assessing the impact of: positive bias, persuasive language, creative visual manipulation and performance comparisons over the unsophisticated users of accounting opinion. We have chosen this particular category since retail investors have been identified as relying on the information provided in corporate annual reports for decision making (Wills, 2008. Based on their relative inexperience and limited knowledge of these investors it is plausible that they can be mislead easily comparing to more sophisticated users of accounting information, as financial analysts. The main argument for conducting such a research is the fact that little research was conducted so far and the effects of creative disclosure on investment decision cannot be assessed so far. Based on this, we conducted a laboratory experiment where participants where provided with an informational set of financial data and required to make an investment decision. Our results document that the users perceptions is strongly affected by creative disclosure, contradictory with previous results documented in the literature, that their opinion cannot be influenced since they relay mostly on numerical information and less on the narrative segments of the financial statements. Even if our sample compressed few participants, we consider the results conclusive. A further research can extend the sample and test if our research hypothesis can be validated. Another possible spring of research can deal with the assessing of the opinion of the users of accounting information that are not considered unsophisticated, as financial analysts.

  18. PROCESS SIMULATION OF BENZENE SEPARATION COLUMN OF LINEAR ALKYL BENZENE (LABPLANT

    Directory of Open Access Journals (Sweden)

    Zaid A. AbdelRahman

    2013-05-01

    Full Text Available       CHEMCAD process simulator was used for the analysis of existing benzene separation column in LAB plant(Arab Detergent Company/Beiji-Iraq.         Simulated column performance curves were constructed. The variables considered in this study are the thermodynamic model option, top and bottom temperatures, feed temperature, feed composition & reflux ratio. Also simulated columns profiles for the temperature, vapor & liquid flow rates compositions, were constructed. Four different thermodynamic models options (SRK, TSRK, PR, and ESSO were used, affecting the results within 1-25% variation for the most cases.            For Benzene Column (32 real stages, feed stage 14, the simulated results show that bottom temperature above 200 oC the weight fractions of top components, except benzene, increases sharply, where as benzene top weight fraction decreasing sharply. Also, feed temperature above 180 oC  shows same trends. The column profiles remain fairly constant from tray 3 (immediately below condenser to tray 10 (immediately above feed and from tray 15 (immediately below feed to tray 25 (immediately above reboiler. Simulation of the benzene separation column in LAB production plant using CHEMCAD simulator, confirms the real plant operation data. The study gives evidence about a successful simulation with CHEMCAD.

  19. Uncertainty in the estimation of benzene risks: application of an uncertainty taxonomy to risk assessments based on an epidemiology study of rubber hydrochloride workers.

    OpenAIRE

    Byrd, D M; Barfield, E T

    1989-01-01

    This paper reviews 14 risk assessments that use the data from descriptions by Rinsky, Young, and co-workers of benzene-associated leukemias among a group of rubber hydrochloride workers in Ohio. The leukemogenic risks of benzene estimated in these assessments differ. The assessors use different assumptions (parameters, confounding factors, or formulas), which account for the differences in risk. The purpose of the review is to determine whether the major source of uncertainty in assessments o...

  20. Experimental study of ozone synthesis

    International Nuclear Information System (INIS)

    A silent discharge ozonizer has been constructed with a design that enables the study of ozone concentration behaviour as a function of different parameters when oxygen used as a working gas. The behaviour of ozone concentration as a function of discharge current density has four characteristic regions. The concentration is enhanced by more than threefold whenever gas pressure is reduced by a factor of two. The flow rate of the working gas is a more effective parameter on ozone concentration than the gas pressure. When the flow rate is kept constant, and the pressure is decreased by 100%, the ozone concentration increases by only 10%. On the other hand, when the flow rate is decreased by 13%, the ozone concentration increases by 200%, whenever the gas pressure is kept constant. The concentration is nearly doubled when the gap space is increased by four times under the same conditions. The length of the discharge region, the thickness and the dielectric constant of the insulating materials are found to have a considerable effect on the generated ozone concentration. Also, the ozone concentration is ten times less when air is used instead of oxygen as a working gas. A maximum efficiency of 185 g/kWh, is obtained for the present system

  1. Pressure Dependence of Molar Volume near the Melting Point in Benzene

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The pressure dependence of the molar volume was at constant temperatures close to the melting point in benzene. The molar volume of benzene was calculated using experimental data for the thermal expansivity for constant temperatures of 25℃, 28.5℃, 40℃, and 51℃ at various pressures for both the solid and liquid phases. The predictions are in good agreement with the observed volumes in both the solid and liquid phases of benzene. The predicted values of the molar volume for a constant temperature of 28.5℃ in the liquid phase of benzene agree well with experimental data in the literature.

  2. Modeling of Pervaporation Separation Benzene from Dilute Aqueous Solutions Through Polydimethylsiloxane Membranes

    Institute of Scientific and Technical Information of China (English)

    彭福兵; 姜忠义

    2005-01-01

    A modified solution-diffusion model was established based on Flory-Huggins thermodynamic theory and Fujita's free volume theory. This model was used for description of the mass transfer of removal benzene from dilute aqueous solutions through polydimethylsiloxane (PDMS) membranes. The effect of component concentration on the interaction parameter between components, that of the polymer membrane on the selectivity to benzene, and that of feed concentration and temperature on the permeation flux and separation factor of benzene/water through PDMS membranes were investigated. Calculated pervaporation fluxes of benzene and water were compared with the experimental results and were in good agreement with the experimental data.

  3. Local Field Factors and Dielectric Properties of Liquid Benzene.

    Science.gov (United States)

    Davari, Nazanin; Daub, Christopher D; Åstrand, Per-Olof; Unge, Mikael

    2015-09-01

    Local electric field factors are calculated for liquid benzene by combining molecular dynamic simulations with a subsequent force-field model based on a combined charge-transfer and point-dipole interaction model for the local field factor. The local field factor is obtained as a linear response of the local field to an external electric field, and the response is calculated at frequencies through the first absorption maximum. It is found that the largest static local field factor is around 2.4, while it is around 6.4 at the absorption frequency. The linear susceptibility, the dielectric constant, and the first absorption maximum of liquid benzene are also studied. The electronic contribution to the dielectric constant is around 2.3 at zero frequency, in good agreement with the experimental value around 2.2, while it increases to 6.3 at the absorption frequency. The π → π* excitation energy is around 6.0 eV, as compared to the gas-phase value of around 6.3 eV, while the experimental values are 6.5 and 6.9 eV for the liquid and gas phase, respectively, demonstrating that the gas-to-liquid shift is well-described. PMID:26241379

  4. Experimental Economics method to study pupils motivation

    OpenAIRE

    Lionel Page

    2010-01-01

    Experimental Economics provide a new set of tools in the tool box of the education economist. This paper review why experimental method may be useful to study how pupils behaviour, formed from their preference and beliefs, may influence their success or failure at school, what are its advantages and what are its limits. Behavioural Economics - Education - Public Policy

  5. Methane-benzene binary mixture destruction in a reverse flow catalytic reactor

    International Nuclear Information System (INIS)

    A reverse flow reactor (RFR) is a packed catalytic bed reactor in which feed flow direction is periodically reversed. When an exothermic catalytic combustion is conducted in a RFR, a hot zone is trapped in the center while both ends of the reactor act as regenerative heat exchanger. This enables an auto thermal operation at high temperatures even for feeds having a low adiabatic temperature rise. These features make RFR highly competitive for VOCs combustion. An experimental study of binary mixture purification in bench scale reverse flow reactor, with an inner diameter of 60 mm, has been carried out. Methane and benzene are chosen due to their different properties. The ignition temperature of methane is higher than any other hydrocarbons and benzene is widely used as solvent in industry. With periodic reversal feed, auto thermal catalytic combustion of very lean binary mixture can be achieved. When peak temperature in the hot zone reaches about 550 degree Celsius, both methane and benzene are well removed and little NOx or no other secondary pollutants are detected. The influence of several operation parameters, such as gas velocity, cycle period and methane-to-benzene ratio are discussed. A mathematical model has been developed and solved using a FORTRAN code, good correspondence being observed between both approaches. This provides a solution if VOC concentration in the contaminated air is too low to maintain an auto thermal operation, while natural gas (which is mainly methane) can be added as auxiliary fuel. (author)

  6. Elevated Atmospheric Levels of Benzene and Benzene-Related Compounds from Unconventional Shale Extraction and Processing: Human Health Concern for Residential Communities

    Science.gov (United States)

    Rich, Alisa L.; Orimoloye, Helen T.

    2016-01-01

    BACKGROUND The advancement of natural gas (NG) extraction across the United States (U.S.) raises concern for potential exposure to hazardous air pollutants (HAPs). Benzene, a HAP and a primary chemical of concern due to its classification as a known human carcinogen, is present in petroleum-rich geologic formations and is formed during the combustion of bypass NG. It is a component in solvents, paraffin breakers, and fuels used in NG extraction and processing (E&P). OBJECTIVES The objectives of this study are to confirm the presence of benzene and benzene-related compounds (benzene[s]) in residential areas, where unconventional shale E&P is occurring, and to determine if benzene[s] exists in elevated atmospheric concentrations when compared to national background levels. METHODS Ambient air sampling was conducted in six counties in the Dallas/Fort Worth Metroplex with passive samples collected in evacuated 6-L Summa canisters. Samples were analyzed by gas chromatography/mass spectrometry, with sampling performed at variable distances from the facility fence line. RESULTS Elevated concentrations of benzene[s] in the atmosphere were identified when compared to U.S. Environmental Protection Agency’s Urban Air Toxics Monitoring Program. The 24-hour benzene concentrations ranged from 0.6 parts per billion by volume (ppbv) to 592 ppbv, with 1-hour concentrations from 2.94 ppbv to 2,900.20 ppbv. CONCLUSION Benzene is a known human carcinogen capable of multisystem health effects. Exposure to benzene is correlated with bone marrow and blood-forming organ damage and immune system depression. Sensitive populations (children, pregnant women, elderly, immunocompromised) and occupational workers are at increased risk for adverse health effects from elevated atmospheric levels of benzene[s] in residential areas with unconventional shale E&P. PMID:27199565

  7. Comparative Investigation of Benzene Steam Reforming over Spinel Supported Rh and Ir Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Mei, Donghai; Lebarbier, Vanessa MC; Rousseau, Roger J.; Glezakou, Vassiliki Alexandra; Albrecht, Karl O.; Kovarik, Libor; Flake, Matthew D.; Dagle, Robert A.

    2013-06-01

    In a combined experimental and first-principles density functional theory (DFT) study, benzene steam reforming (BSR) over MgAl2O4 supported Rh and Ir catalysts was investigated. Experimentally, it has been found that both highly dispersed Rh and Ir clusters (1-2 nm) on the MgAl2O4 spinel support are stable during the BSR in the temperature range of 700-850˚C. Compared to the Ir/MgAl2O4 catalyst, the Rh/MgAl2O4 catalyst is more active with higher benzene turnover frequency and conversion. At typical steam conditions with the steam-to-carbon ratio > 12, the benzene conversion is only a weak function of the H2O concentration in the feed. This suggests that the initial benzene decomposition step rather than the benzene adsorption is most likely the rate-determined step in BSR over supported Rh and Ir catalysts. In order to understand the differences between the two catalysts, we followed with a comparative DFT study of initial benzene decomposition pathways over two representative model systems for each supported metal (Rh and Ir) catalysts. A periodic terrace (111) surface and an amorphous 50-atom metal cluster with a diameter of 1.0 nm were used to represent the two supported model catalysts under low and high dispersion conditions. Our DFT results show that the decreasing catalyst particle size enhances the benzene decomposition on supported Rh catalysts by lowering both C-C and C-H bond scission. The activation barriers of the C-C and the C-H bond scission decrease from 1.60 and 1.61 eV on the Rh(111) surface to 1.34 and 1.26 eV on the Rh50 cluster. For supported Ir catalysts, the decreasing particle size only affects the C-C scission. The activation barrier of the C-C scission of benzene decreases from 1.60 eV on the Ir(111) surface to 1.35 eV on the Ir50 cluster while the barriers of the C-H scission are practically the same. The experimentally measured higher BSR activity on the supported highly dispersed Rh catalyst can be rationalized by the thermodynamic

  8. In vivo toxicity of a new antifungal agent 2,4-dithiophenoxy-1-iodo-4-bromo benzene: a follow up on our in vitro study.

    Science.gov (United States)

    Kılıç Süloğlu, Aysun; Koçkaya, Evrim; Karacaoğlu, Elif; Selmanoğlu, Güldeniz; Loğoğlu, Elif

    2015-03-01

    Triazole fungicide fluconazole has become the most widely used antifungal agent in the world, mainly because of its ability to penetrate well into body fluids and tissues. However, it has been reported to interact with many drugs and because of its common use, the risk of resistance to fluconazole increases. This calls for new anti-fungal drugs that would be able to replace it. In 2006, a new thialo benzene derivative - 2,4-dithiophenoxy-1-iodo-4-bromo benzene (C18H12S2IBr) - was synthesised with a carbon backbone similar to fluconazole, and, according to the early in vitro tests, much greater efficiency. Followed an in vitro test of its cytotoxicity, in which the new drug showed promising results as an alternative to fluconazole. The aim of this study was take the next step and test C18H12S2IBr toxicity in vivo. We opted for a four-week test on Wistar rats, in which the new antifungal agent was orally applied at doses two and a half and five times lower than those of fluconazole. There were no changes in daily food and water consumption, but weight gain in female rats and relative organ weights changed in the treated groups, pointing to sex-related differences in drug metabolism and effects. Fluconazole significantly increased leukocytes and lowered neutrophils whereas C18H12S2IBr did not, while other haematological changes in respect to the vehicle control were similar between the treated groups. Differences in cytochrome c in the liver and kidney suggested greater apoptotic effect of the new drug, but interpretation remains inconclusive, considering that other key indicators (biochemistry and histopathology) do not support greater toxicity. Considering that C18H12S2IBr is more active at lower concentrations and has comparable toxic effects to fluconazole in rats, this new compound shows some promise in the treatment of fungal infections. Future, more detailed animal studies are needed, that will include drug interactions and molecular toxicity pathways. If the

  9. Modulation of mast cell and basophil functions by benzene metabolites.

    Science.gov (United States)

    Triggiani, Massimo; Loffredo, Stefania; Granata, Francescopaolo; Staiano, Rosaria I; Marone, Gianni

    2011-11-01

    Benzene is a carcinogenic compound used in industrial manufacturing and a common environmental pollutant mostly derived from vehicle emissions and cigarette smoke. Benzene exposure is associated with a variety of clinical conditions ranging from hematologic diseases to chronic lung disorders. Beside its direct toxicity, benzene exerts multiple effects after being converted to reactive metabolites such as hydroquinone and benzoquinone. Mast cells and basophils are primary effector cells involved in the development of respiratory allergies such as rhinitis and bronchial asthma and they play an important role in innate immunity. Benzene and its metabolites can influence mast cell and basophil responses either directly or by interfering with other cells, such as T cells, macrophages and monocytes, which are functionally connected to mast cells and basophils. Hydroquinone and benzoquinone inhibit the release of preformed mediators, leukotriene synthesis and cytokine production in human basophils stimulated by IgE- and non IgE-mediated agonists. Furthermore, these metabolites reduce IgE-mediated degranulation of mast cells and the development of allergic lung inflammation in rats. Both in vitro and in vivo studies indicate that benzene metabolites alter biochemical and functional activities of other immunocompetent cells and may impair immune responses in the lung. These inhibitory effects of benzene metabolites are primarily mediated by interference with early transduction signals such as PI3 kinase. Together, currently available studies indicate that benzene metabolites interfere by multiple mechanisms with the role of basophils and mast cells in innate immunity and in chronic inflammation in the lung. PMID:22103854

  10. Solar Powered Vapor Absorption System Using Propane And Alkylated Benzene Ab300 Oil

    OpenAIRE

    Al-Dadah, R.K.; Jackson, G.; Rezk, Ahmed

    2011-01-01

    Abstract This paper describes experimental work on a solar assisted vapour absorption air conditioning system using Propane (refrigerant) and Alkylated Benzene (AB300?refrigeration lubrication oil, absorbent). Preliminary experiments to assess the miscibility of propane in various lubricating oils namely Shell Clavus oils 32 and 64 and Alkylated Benzene oils AB150 and AB300 indicated that Propane is most miscible in Alkylated Benzene AB300. The vapour absorption system is a single ...

  11. The Grand Canonical Monte Carlo Simulations of Benzene and Propylene in ITQ-1 Zeolite

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Grand Canonical Monte Carlo (GCMC) simulations have been performed to study the localization and adsorption behavior of benzene and propylene, in purely siliceous MWW zeolite (ITQ-1). By analyzing the locations of benzene and propylene in ITQ-1, it can be deduced that the alkylation of benzene and propylene will mainly happen in 12-MR supercages at the external surface or close to the external surface. The adsorption isotherms of benzene and propylene at 315K and 0~3.5kPa are predicted, and the results for benzene generally coincide with the trend from the experiments of a series of aromatic compounds.

  12. Benzene conversion by manganese dioxide assisted silent discharge plasma

    Institute of Scientific and Technical Information of China (English)

    LU Bin; JI Min; YU Xin; FENG Tao; YAO Shuiliang

    2007-01-01

    Non-thermal plasma technologies have shown their promising potential specially for the low concentration of volatile organic compound control in indoor air in recent years.But it is also high energy consuming.So,to improve the energy efficiency,adding catalysts which enhance the plasma chemical reactions to plasma reactors may be a good selection.Therefore,in this study the manganese dioxide assisted silent discharge plasma was developed for benzene conversion at a relatively high energy efficiency.The results show that MnO2 could promote complete oxidation of benzene with O2 and O3 produced in the plasma discharge zone.The energy efficiency of benzene conversion with MnO2 was two folds as much as that without catalysts.It was also found that the site of MnO2 in the reactor and the energy density had effects on benzene conversion.While the energy density was lower than 48 J/L,benzene conversion decreased with the increase in the distance between MnO2 bed and the plasma discharge zone.Whereas when the energy density was higher than 104 J/L,benzene conversion had an optimal value that was governed by the distance between MnO2 bed and the plasma discharge zone.The mechanism of benzene oxidation in plasma discharges and over MnO2 is discussed in detail.

  13. Assessment of benzene induced oxidative impairment in rat isolated pancreatic islets and effect on insulin secretion.

    Science.gov (United States)

    Bahadar, Haji; Maqbool, Faheem; Mostafalou, Sara; Baeeri, Maryam; Rahimifard, Mahban; Navaei-Nigjeh, Mona; Abdollahi, Mohammad

    2015-05-01

    Benzene (C6H6) is an organic compound used in petrochemicals and numerous other industries. It is abundantly released to our environment as a chemical pollutant causing widespread human exposure. This study mainly focused on benzene induced toxicity on rat pancreatic islets with respect to oxidative damage, insulin secretion and glucokinase (GK) activity. Benzene was dissolved in corn oil and administered orally at doses 200, 400 and 800mg/kg/day, for 4 weeks. In rats, benzene significantly raised the concentration of plasma insulin. Also the effect of benzene on the release of glucose-induced insulin was pronounced in isolated islets. Benzene caused oxidative DNA damage and lipid peroxidation, and also reduced the cell viability and total thiols groups, in the islets of exposed rats. In conclusion, the current study revealed that pancreatic glucose metabolism is susceptible to benzene toxicity and the resultant oxidative stress could lead to functional abnormalities in the pancreas. PMID:25935538

  14. Intrinsic and enhanced biodegradation of benzene in strongly reduced aquifers

    NARCIS (Netherlands)

    Heiningen, W.N.M. van; Rijnaarts, H.H.M; Langenhoff, A.A.M.

    1999-01-01

    Laboratory microcosm studies were performed to examine intrinsic and enhanced benzene bioremediation using five different sediment and groundwater samples from three deeply anaerobic aquifers sited in northern Netherlands. The influence of addition of nitrate, sulfate, limited amounts of oxygen, and

  15. Benzene exposure: an overview of monitoring methods and their findings.

    Science.gov (United States)

    Weisel, Clifford P

    2010-03-19

    Benzene has been measured throughout the environment and is commonly emitted in several industrial and transportation settings leading to widespread environmental and occupational exposures. Inhalation is the most common exposure route but benzene rapidly penetrates the skin and can contaminant water and food resulting in dermal and ingestion exposures. While less toxic solvents have been substituted for benzene, it still is a component of petroleum products, including gasoline, and is a trace impurity in industrial products resulting in continued sub to low ppm occupational exposures, though higher exposures exist in small, uncontrolled workshops in developing countries. Emissions from gasoline/petrochemical industry are its main sources to the ambient air, but a person's total inhalation exposure can be elevated from emissions from cigarettes, consumer products and gasoline powered engines/tools stored in garages attached to homes. Air samples are collected in canisters or on adsorbent with subsequent quantification by gas chromatography. Ambient air concentrations vary from sub-ppb range, low ppb, and tens of ppb in rural/suburban, urban, and source impacted areas, respectively. Short-term environmental exposures of ppm occur during vehicle fueling. Indoor air concentrations of tens of ppb occur in microenvironments containing indoor sources. Occupational and environmental exposures have declined where regulations limit benzene in gasoline (<1%) and cigarette smoking has been banned from public and work places. Similar controls should be implemented worldwide to reduce benzene exposure. Biomarkers of benzene used to estimate exposure and risk include: benzene in breath, blood and urine; its urinary metabolites: phenol, t,t-muconic acid (t,tMA) and S-phenylmercapturic acid (sPMA); and blood protein adducts. The biomarker studies suggest benzene environmental exposures are in the sub to low ppb range though non-benzene sources for urinary metabolites, differences

  16. Electronic structure of benzene adsorbed on Ni and Cu surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Weinelt, M.; Nilsson, A.; Wassdahl, N. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    Benzene has for a long time served as a prototype adsorption system of large molecules. It adsorbs with the molecular plane parallel to the surface. The bonding of benzene to a transition metal is typically viewed to involve the {pi} system. Benzene adsorbs weakly on Cu and strongly on Ni. It is interesting to study how the adsorption strength is reflected in the electronic structure of the adsorbate-substrate complex. The authors have used X-ray Emission (XE) and X-ray Absorption (XA) spectroscopies to selectively study the electronic states localized on the adsorbed benzene molecule. Using XES the occupied states can be studies and with XAS the unoccupied states. The authors have used beamline 8.0 and the Swedish endstation equipped with a grazing incidence x-ray spectrometer and a partial yield absorption detector. The resolution in the XES and XAS were 0.5 eV and 0.05 eV, respectively.

  17. Identification of genes specifically required for the anaerobic metabolism of benzene in Geobacter metallireducens

    DEFF Research Database (Denmark)

    Zhang, Tian; Tremblay, Pier-Luc; Chaurasia, Akhilesh Kumar;

    2014-01-01

    Although the biochemical pathways for the anaerobic degradation of many of the hydrocarbon constituents in petroleum reservoirs have been elucidated, the mechanisms for anaerobic activation of benzene, a very stable molecule, are not known. Previous studies have demonstrated that Geobacter...... metallireducens can anaerobically oxidize benzene to carbon dioxide with Fe(III) as the sole electron acceptor and that phenol is an intermediate in benzene oxidation. In an attempt to identify enzymes that might be involved in the conversion of benzene to phenol, whole-genome gene transcript abundance was...... compared in cells metabolizing benzene and cells metabolizing phenol. Eleven genes had significantly higher transcript abundance in benzene-metabolizing cells. Five of these genes had annotations suggesting that they did not encode proteins that could be involved in benzene metabolism and were not further...

  18. Experimental radiation carcinogenesis is studies at NIRS

    International Nuclear Information System (INIS)

    Experimental radiation carcinogenesis studies conducted during the past decade at NIRS are briefly reviewed. They include the following: 1) Age dependency of susceptibility to radiation carcinogenesis. 2) Radiation-induced myeloid leukemia. 3) Mechanism of fractionated X-irradiation (FX) induced thymic lymphomas. 4) Significance of radiation-induced immunosuppression in radiation carcinogenesis in vivo. 5) Other ongoing studies. (author)

  19. Experimental study of the radiodepolymerization of starch

    International Nuclear Information System (INIS)

    The radiodepolymerization of starch is studied by means of investigating the variations of intrinsic viscosity and of the rate of water-soluble products. The experimental results corroborate the theoretical laws proposed in an earlier paper. Special study of watersoluble products shows how the theoretical laws can be used to investigate the chemical functions radioinduced on the chains of dextrins. (orig.)

  20. Experimental study of tile grout material behavior

    OpenAIRE

    Kumpová, I. (Ivana); Kloiber, M. (Michal); Ševčík, R. (Radek); Kytýř, D. (Daniel)

    2014-01-01

    Study provides preliminary results of experimental study of tile grout material behavior. Experiments were performed with the use of microCT, three point bending test and methods for chemical analysis. It was proven that material behave very elastic and the suitability of the combination of used methods.

  1. Homolytic iodination and nitration of some benzene derivatives in the gas phase

    International Nuclear Information System (INIS)

    Two gas phase reactions, involving the iodination and nitration of benzene derivatives, are described. The experimental techniques of the apparatus and the methods used are outlined. The kinetic H/D isotope effect in the gas phase nitration of benzene with NO2 is determined. (C.F.)

  2. Formation of reactive metabolites from benzene

    International Nuclear Information System (INIS)

    Rat liver mitoplasts were incubated first with [3H]dGTP, to form DNA labeled in G, and then with [14C]benzene. The DNA was isolated and upon isopycnic density gradient centrifugation in CsCl yielded a single fraction of DNA labeled with both [3H] and [14C]. These data are consistent with the covalent binding of one or more metabolites of benzene to DNA. The DNA was enzymatically hydrolyzed to deoxynucleosides and chromatographed to reveal at least seven deoxyguanosine adducts. Further studies with labeled deoxyadenine revealed one adduct on deoxyadenine. [3H]Deoxyguanosine was reacted with [14C]hydroquinone or benzoquinone. The product was characterized using uv, fluorescence, mass and NMR spectroscopy. A proposed structure is described. (orig.)

  3. Exposure to benzene metabolites causes oxidative damage in Saccharomyces cerevisiae.

    Science.gov (United States)

    Raj, Abhishek; Nachiappan, Vasanthi

    2016-06-01

    Hydroquinone (HQ) and benzoquinone (BQ) are known benzene metabolites that form reactive intermediates such as reactive oxygen species (ROS). This study attempts to understand the effect of benzene metabolites (HQ and BQ) on the antioxidant status, cell morphology, ROS levels and lipid alterations in the yeast Saccharomyces cerevisiae. There was a reduction in the growth pattern of wild-type cells exposed to HQ/BQ. Exposure of yeast cells to benzene metabolites increased the activity of the anti-oxidant enzymes catalase, superoxide dismutase and glutathione peroxidase but lead to a decrease in ascorbic acid and reduced glutathione. Increased triglyceride level and decreased phospholipid levels were observed with exposure to HQ and BQ. These results suggest that the enzymatic antioxidants were increased and are involved in the protection against macromolecular damage during oxidative stress; presumptively, these enzymes are essential for scavenging the pro-oxidant effects of benzene metabolites. PMID:27016252

  4. Study on the decomposition of trace benzene over V2O5–WO3/TiO2-based catalysts in simulated flue gas

    Science.gov (United States)

    Trace levels (1 and 10 ppm) of gaseous benzene were catalytically decomposed in a fixed-bed catalytic reactor with monolithic oxides of vanadium and tungsten supported on titanium oxide (V2O5–WO3/TiO2) catalysts under conditions simulating the cooling of waste incineration flue g...

  5. A combination of 3D-QSAR, docking, local-binding energy (LBE) and GRID study of the species differences in the carcinogenicity of benzene derivatives chemicals.

    Science.gov (United States)

    Fratev, Filip; Benfenati, Emilio

    2008-09-01

    A combination of 3D-QSAR, docking, local-binding energy (LBE) and GRID methods was applied as a tool to study and predict the mechanism of action of 100 carcinogenic benzene derivatives. Two 3D-QSAR models were obtained: (i) model of mouse carcinogenicity on the basis of 100 chemicals (model 1) and (ii) model of the differences in mouse and rat carcinogenicity on the basis of 73 compounds (model 2). 3D-QSAR regression maps indicated the important differences in species carcinogenicity, and the molecular positions associated with them. In order to evaluate the role of P450 metabolic process in carcinogenicity, the following approaches were used. The 3D models of CYP2E1 for mouse and rat were built up. A docking study was applied and the important ligand-protein residues interactions and oxidation positions of the molecules were identified. A new approach for quantitative assessment of metabolism pathways was developed, which enabled us to describe the species differences in CYP2E1 metabolism, and how it can be related to differences in the carcinogenic potential for a subset of compounds. The binding energies of the important substituents (local-binding energy-LBE) were calculated, in order to quantitatively demonstrate the contribution of the substituents in metabolic processes. Furthermore, a computational procedure was used for determining energetically favourable binding sites (GRID examination) of the enzymes. The GRID procedure allowed the identification of some important differences, related to species metabolism in CYP2E1. Comparing GRID, 3D-QSAR maps and LBE results, a similarity was identified, indicating a relationship between P450 metabolic processes and the differences in the carcinogenicity. PMID:18495507

  6. Raman Frequencies Calculated at Various Pressures in Phase I of Benzene

    International Nuclear Information System (INIS)

    We calculate in this study the pressure dependence of the frequencies for the Raman modes of A (Ag), B (Ag, B2g) and C (B1g, B3g) at constant temperatures of 274 and 294K (room temperature) for the solid phase I of benzene. Using the mode Gruneisen parameter of each lattice mode, which correlates the pressure dependence of the crystal volume and the frequency, the Raman frequencies of those modes are computed for phase I of benzene. Our results show that the Raman frequencies of the three lattice modes (A, B and C) increase as the pressure increases, as expected. The temperature effect on the Raman frequencies is not significant, which can be explained by the experimental measurements

  7. Volumetric properties of binary mixtures of benzene with cyano-based ionic liquids

    Science.gov (United States)

    Gonfa, Girma; Bustam, Mohamad Azmi; Moniruzzaman, Muhammad; Murugesan, Thanabalan

    2014-10-01

    The objective of this study is to investigate the volumetric properties of the binary mixtures comprised benzene and two ionic liquids, 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) and 1-butyl-3-methyl- imidazolium dicyanamide ([ BMIM ][ N ( CN )2]( . Densities (ρ) and viscosities (μ) of the binary mixtures were measured over a temperature range of 293.15 to 323.15 K and at atmospheric pressure. Excess molar volumes and viscosity deviations were calculated from the experimental densities and viscosities values. The volumetric properties of the mixtures were changed significantly with the change of compositions and temperatures. It was also found that the value of excess molar volume and viscosity deviations were negative (-ve) over the entire range of compositions. The results have been interpreted in terms of molecular interactions of ILs and benzene.

  8. Sudden Termination Auctions—An Experimental Study

    NARCIS (Netherlands)

    Füllbrunn, S.C.; Sadrieh, A.

    2012-01-01

    The design of online markets has become a major issue due to the capability of operators to implement almost any set of market rules overnight. With this study we contribute to the literature of auction market design by presenting a theoretical and experimental analysis of sudden termination auction

  9. (Na, Sr)-Feldspars: an experimental study

    International Nuclear Information System (INIS)

    The distribution of Na and Sr between feldspar (albite-Sr-celsian series) and a salt-bearing fluid at 700 deg C and 2 kbar was studied experimentally. The distribution of the elements between feldspar and the fluid is not ideal. Strontium enriches feldspar relative to the fluid over the entire compositional range. The unit cell parameters of the albite-Sr-celsian solid solutions were refined. The experimental data are used to calculate the excess volumes and energies of mixing of the solid solutions of (Na, Sr)-feldspars, which are approximated by a two-parameter Margules model. 28 refs., 6 figs., 6 tabs

  10. An experimental study on thermal characteristics of nanofluid with graphene and multi-wall carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    A K M Mahmudul Haque; Sunghyun Kwon; Junhyo Kim; Jungpil Noh; Sunchul Huh; Hanshik Chung; Hyomin Jeong

    2015-01-01

    High-thermal conductivity enhancement of nanofluid is one of the promising topics of the nanoscience research field. This work reports the experimental study on the preparation of graphene (GN) and multi-walled carbon nanotubes (MWCNTs) based nanofluids with the assistance of sodium dodecyl benzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS) surfactants, and their thermal behaviors. The present work suggests not a solution, but a solution approach and deduces a new conclusion by trying to resolve the agglomeration problem and improve the dispersibility of nanoparticles in the base fluid. The analysis results of FESEM, thermal conductivity, diffusivity, effusivity and heat transfer coefficient enhancement ratio of nanofluid with surfactants SDS and SDBS expose strong evidence of the dispersing effect of surfactant on the making of nanofluid.

  11. Experimental study of the natural circulation phenomena

    International Nuclear Information System (INIS)

    The objective of this paper is to study the natural circulation in experimental loops and extend the results to nuclear facilities. New generation of compact nuclear power plants use the natural circulation as cooling and residual heat removal systems in case of accidents or shutdown. Lately the interest in this phenomenon, by scientific community, has increased. The experimental loop, described in this paper, was assembled at Escola Politecnica - USP at the Chemical Engineering Department. It is the goal to generate information to help with the understanding of the one and two phase natural circulation phenomena. Some experiments were performed with different levels of heat power and different flow of the cooling water at the secondary circuit. The data generated from these experiments are going to be used to validate some computational thermal hydraulic codes. Experimental results for one and two phase regimes are presented as well as the proposed model to simulate the flow regimes with the RELAP5 code. (author)

  12. Immunoprophylactic potential of wheat grass extract on benzene-induced leukemia: An in vivo study on murine model

    OpenAIRE

    Neelofar Khan; Aditya Ganeshpurkar; Nazneen Dubey; Divya Bansal

    2015-01-01

    Objectives: Wheat grass (Triticum aestivum) is a gift of nature given to mankind. A number of scientific research on wheatgrass establishes its anticancer and antioxidant potential. Current work was focused to determine antileukemic effect of wheat grass. Materials and Methods: The commercial wheatgrass powder was extracted with 95% of methanol. Methanol extract of wheat grass was studied for acute oral toxicity as per revised Organization for Economic Cooperation and Development Guidelin...

  13. Accumulation of chlorinated benzenes in earthworms

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, W.N. [Patuxent Wildlife Research Center, Laurel, MD (United States)

    1996-12-31

    Chlorinated benzenes are widespread in the environment. Hexachlorobenzene, pentachlorobenzene and all isomers of dichlorobenzenes, trichlorobenzenes, and tetrachlorobenzenes, have been detected in fish, water, and sediments from the Great Lakes. They probably entered the water as leachates from chemical waste dumps and as effluents from manufacturing. Hexachlorobenzene and pentachlorobenzene are commonly present in Herring gull (Larus argentatus) eggs from the Great Lakes, and some of the isomers of trichlorobenzene and tetrachlorobenzene are occasionally detected at low concentrations. Hexachlorobenzene, which was formerly used as a fungicide, has been the most thoroughly studied chlorinated benzene, and has been detected in many species. Its use as a fungicide in the United States was canceled in 1984. Since about 1975 hexachlorobenzene has been formed mainly in the production of chlorinated solvents. It is highly persistent in the environment and some species are poisoned by hexachlorobenzene at very low chronic dietary exposures. As little as 1 ppm in the diet of mink (Mustela vison) reduced the birth weights of young, and 5 ppm in the diet of Japanese quail (Coturnix coturnix japonica) caused slight liver damage. This paper describes a long-term (26 wk) experiment relating the concentrations of chlorinated benzenes in earthworms to length of exposure and three 8 wk experiments relating concentration to the concentration in soil the soil organic matter content, and the degree of chlorination. 20 refs., 3 figs., 1 tab.

  14. Experimental and Modelling Studies of Biomass Pyrolysis

    Institute of Scientific and Technical Information of China (English)

    Ka Leung Lam; Adetoyese Olajire Oyedu~; Chi Wai Hui

    2012-01-01

    The analysis on the feedstock pyrolysis characteristic and the impacts of process parameters on pyrolysis outcomes can assist in the designing, operating and optimizing pyrolysis processes. This work aims to utilize both experimental and modelling approaches to perform the analysis on three biomass feedstocks--wood sawdust, bamboo shred and Jatropha Curcas seed cake residue, and to provide insights for the design_and operation of pyro-lysis processes. For the experimental part, the study investigated the effect of heating rate, final pyrolysis tempera- ture and sample size on pyrolysis using common thermal analysis techniques. For the modelling part, a transient mathematical model that integrates the feedstock characteristic from the experimental study was used to simulate the pyrolysis progress of selected biomass feedstock particles for reactor scenarios. The model composes of several sub-models that describe pyrolysis kinetic and heat flow, particle heat transfer, particle shrinking and reactor opera-tion. With better understanding of the effects of process conditions and feedstock characteristics on pyrolysis through both experimental and modelling studies, this work discusses on the considerations of and interrelation between feedstock size, pyrolysis energy usage, processing time and product quality for the design and operation of pyrolysis processes.

  15. Money, Happiness, and Aspirations: An Experimental Study

    OpenAIRE

    Michael McBride

    2007-01-01

    The past decade has witnessed an explosion of interest in the scientific study of happiness. Economists, in particular, find that happiness increases in income but decreases in income aspirations, and this work prompts examination of how aspirations form and adapt over time. This paper presents results from the first experimental study of how multiple factors -- past payments, social comparisons, and expectations -- influence aspiration formation and reported satisfaction. I find that expecta...

  16. Removal of the hazardous, volatile, and organic compound benzene from aqueous solution using phosphoric acid activated carbon from rice husk

    OpenAIRE

    Yakout, Sobhy M

    2014-01-01

    Background Benzene is one of the most hazardous organic pollutants in groundwater. The removal of benzene from water is very important from a health point of view and for environmental protection. In this study, benzene adsorption kinetics was investigated using phosphoric acid activated carbon, prepared from rice husk. Results An initial rapid uptake of benzene was observed and became almost constant after 40 minutes of contact. Kinetic data was analyzed using pseudo first order, pseudo seco...

  17. [Experimental study of pinostrobine oxime biotransformation].

    Science.gov (United States)

    Sariev, A K; Abaimov, D A; Tankevich, M V; Prokhorov, D I; Adekenov, S M; Arystan, L I; Seĭfulla, R D

    2014-01-01

    We have experimentally studied pathways of elimination of an oximized derivative of phytoflavonoid pinostrobine by HPLC/mass spectrometry. Four potential metabolites of pinostrobine oxime have been found and there was an attempt to determine their molecular structures on the basis of their fragmentation under positive electrospray ionization conditions. It is established that pinostrobine oxime is removed from the organism mainly unchanged and also in the form of glucuronated derivative. PMID:25335390

  18. Experimental Studies of Artificial Conscious Systems

    Institute of Scientific and Technical Information of China (English)

    蔡义发

    1995-01-01

    Human consciousness is the most interesting and mysterious phenomenon in the world.In this paper,the results of the computational study and simulation of the conscious behaviour,such as the learning of language and image patterns,traditional conditioning,association,imagination and dream,have been presented.Based on these results,an experimental conscious systekm-CONSCITRON,has been developed.Further discussion on development of artificial conscious systems is also provided.

  19. Experimental study of rare charged pion decays

    CERN Document Server

    Pocanic, Dinko; van der Schaaf, Andries

    2014-01-01

    The combination of simple dynamics, small number of available decay channels, and extremely well controlled radiative and loop corrections, make charged pion decays a sensitive means for testing the underlying symmetries and the universality of weak fermion couplings, as well as for improving our understanding of pion structure and chiral dynamics. This paper reviews the current state of experimental study of the allowed rare decays of charged pions: (a) leptonic, $\\pi^+ \\to e^+\

  20. Theoretical and experimental studies of elementary particles

    International Nuclear Information System (INIS)

    This report discusses: Fixed target experimentation at Fermilab; the D-zero collider experiment at Fermilab; deep inelastic lepton nucleon scattering; non-accelerator experiments and non-linear QED; the AMY experiment at TRISTAN and other activities at KEK; the collider detector at Fermilab; laser switched linac; preparations for experiments at the SSC; search for massive stable particles; and the Advanced Study Institute on techniques and concepts of high energy physics

  1. Solvodynamics of Benzene and Water Phases by DTAB, MTOAC, TMSOI and Orcinol Studied with Interfacial Tension, Surface Tension and Viscosity Measured with Survismeter

    Directory of Open Access Journals (Sweden)

    Vinod Kumar

    2008-12-01

    Full Text Available Both benzene and water immiscible phases when mixed together develop an energetic interface that remains tense due to individual surface tensions. Physics of a tense interface does equilibrate tensional forces to have an optimized surface force which is denoted as Interfacial Tension (IFT, mN/m. The IFT between water and benzene with addition of surfactants: dodecyltrimethylammonium bromide (DTAB, trimethylsulfoxonium iodide (TMSOI, methyltrioctylammonium chloride (MTOAC and 3,5-dihydroxytoluene monohydrate (Orcinol critically decrease to 15.69, 12.86, 10.59, 8.36, 2.97 mN/m for DTAB , TMSOI, water, orcinol, MTOAC respectively. This lowering of IFT infers a higher mutual miscibility (MM of the phases denoted as wetting. The DTAB and orcinol increased surface tension of water from 71.25 to 79.55 and 72.70 mN/m respectively at 304.65 Kelvin temperature due to stronger cohesive forces.

  2. Spectroscopic study on deuterated benzenes. II. High-resolution laser spectroscopy and rotational structure in the S{sub 1} state

    Energy Technology Data Exchange (ETDEWEB)

    Kunishige, Sachi; Katori, Toshiharu; Baba, Masaaki, E-mail: baba@kuchem.kyoto-u.ac.jp [Division of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Hayashi, Masato [Institute for Molecular Science, National Institute of Natural Science, Myodaiji, Okazaki 444-8585 (Japan); Hasegawa, Hirokazu [Department of Basic Science, Graduated School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902 (Japan); Ohshima, Yasuhiro [Institute for Molecular Science, National Institute of Natural Science, Myodaiji, Okazaki 444-8585 (Japan); Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, Ohokayama, Meguro-ku, Tokyo 152-8551 (Japan)

    2015-12-28

    High-resolution spectra of the S{sub 1}←S{sub 0} transition in jet-cooled deuterated benzenes were observed using pulse dye amplification of single-mode laser light and mass-selective resonance enhanced multiphoton ionization (REMPI) detection. The vibrational and rotational structures were accurately analyzed for the vibronic levels in the S{sub 1} state. The degenerate 6{sup 1} levels of C{sub 6}H{sub 6} or C{sub 6}D{sub 6} are split into 6a{sup 1} and 6b{sup 1} in many of deuterated benzenes. The rigid-rotor rotational constants were assessed and found to be slightly different between 6a and 6b because of different mean molecular structures. Their rotational levels are significantly shifted by Coriolis interactions. It was found that the Coriolis parameter proportionally changed with the number of substituted D atoms.

  3. Combined effects of simultaneous γ-rays irradiation and inhalation of benzene, toluene and carbon monoxide on rabbits

    International Nuclear Information System (INIS)

    Combined effects on rabbits induced by γ-rays irradiation in combination with inhalation of benzene, toluene and carbon monoxide and the interactive characteristics (antagonistic, additive or synergistic) of these agents were studied. Ninety healthy male rabbits were equally divided into 9 groups, eight of which were test groups assigned according to four factor- two-dose-level orthogonal layout [L8(27)] program and one was the control. The two dose-levels of the four factors were: for γ-rays irradiation, 0.0075 Gy/d and 0.0375 Gy/d, and for benzene, toluene and carbon monoxide, 40 +- 15 mg/m3 and 182 +- 33 mg/m3, 90 +- 30 mg/m3 and 407 +- 68 mg/m3, 93 +- 4 mg/m3 and 278 +- 8 mg/m3 respectively. The animals were exposed to γ-rays irradiation combined with benzene, toluene and CO vapor 2h a day and 5 days a week for a period of 8 weeks. Experimental results were analysed with the method of variance analysis and the test groups were compared. The results showed that (1) the interactive factor, the ratio (ω) of the combined effects caused by the four agents to the sum of the four independent effects induced by those agents, was 2.16, 1.58, 2.07, 2.67, 1.31 and 1.18 for dicentric + ring, acentric, aberration cells, total aberration, micronuclei and SCEs/C in lymphocytes respectively, and the ratio for aberrant sperms was as high as 5.97. The ratios showed that interactions were mainly synergistic (ω > 1). However, for acentric interactions between γ-rays and benzene was antagonistic. (2) The four agents could all obviously cause decrease in testis weight index, and γ-rays, benzene and CO could markedly reduce the number of sperms and increase the ratio of aberrant sperms. The interactions between γ-rays and benzene for the decrease in testis weight index and for the elevation of the ratio of aberrant sperms were synergistic. (3) CO could cause decrease in total amount of leucocytes, thrombocytes and hemoglobin, and toluene cause decrease in lymphocytes. (4

  4. Interior and interfacial aqueous solvation of benzene dicarboxylate dianions and their methylated analogues: A combined molecular dynamics and photoelectron spectroscopy study

    Czech Academy of Sciences Publication Activity Database

    Minofar, B.; Vrbka, Luboš; Mucha, Martin; Jungwirth, Pavel; Yang, X.; Wang, X. B.; Fu, Y. J.; Wang, L. S.

    2005-01-01

    Roč. 109, - (2005), s. 5042-5049. ISSN 1089-5639 R&D Projects: GA MŠk(CZ) ME 644; GA MŠk(CZ) LC512 Grant ostatní: NSF(US) CHE041312; NSF(US) CHE0209719 Institutional research plan: CEZ:AV0Z40550506 Keywords : benzene dicarboxylate dianions * molecular dynamics * photoelectron spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.898, year: 2005

  5. 27 CFR 21.97 - Benzene.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Benzene. 21.97 Section 21... TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.97 Benzene. (a..., Standard No. D 836-77; for incorporation by reference, see § 21.6(b).) When 100 ml of benzene are...

  6. Fully Bayesian Experimental Design for Pharmacokinetic Studies

    Directory of Open Access Journals (Sweden)

    Elizabeth G. Ryan

    2015-03-01

    Full Text Available Utility functions in Bayesian experimental design are usually based on the posterior distribution. When the posterior is found by simulation, it must be sampled from for each future dataset drawn from the prior predictive distribution. Many thousands of posterior distributions are often required. A popular technique in the Bayesian experimental design literature, which rapidly obtains samples from the posterior, is importance sampling, using the prior as the importance distribution. However, importance sampling from the prior will tend to break down if there is a reasonable number of experimental observations. In this paper, we explore the use of Laplace approximations in the design setting to overcome this drawback. Furthermore, we consider using the Laplace approximation to form the importance distribution to obtain a more efficient importance distribution than the prior. The methodology is motivated by a pharmacokinetic study, which investigates the effect of extracorporeal membrane oxygenation on the pharmacokinetics of antibiotics in sheep. The design problem is to find 10 near optimal plasma sampling times that produce precise estimates of pharmacokinetic model parameters/measures of interest. We consider several different utility functions of interest in these studies, which involve the posterior distribution of parameter functions.

  7. Experimental study on partial coherence source

    CERN Document Server

    Zhao Xue Qing; Yuan Xiao; LiuJingRu; Wang Long Hua; Tang Ying; Huang, Kerson

    2002-01-01

    Partial coherence source is a key part in the laser system using echelon-free introduced spatial incoherence beam smoothing technique. Different kinds of partial coherence sources have been studied experimentally for improving the uniformity of laser intensity distribution. It is found that the source produced by excimer laser scattering on the surface of a teflon plate is ideal. The properties of this kind of source are studied. As a result, the uniformity of source beam intensity distribution, the beam spatial coherence and energy transfer efficiency of the source are obtained

  8. Core seismic study on experimental VHTR

    International Nuclear Information System (INIS)

    The experimental Very High Temperature Reactor (VHTR) core consists of about 1700 blocks (fuel blocks, replaceable reflectors, permanent reflectors, and core support blocks) and other structures surrounding the blocks. A major research and development effort was initiated in 1975 to study the dynamic response of the experimental VHTR core arrangement to seismic excitation. First, a VHTR core seismic test program was prepared. Next, basic tests and analysis were carried out according to the program. Tests and apparatus and test results are described for one-column and one-region tests, vertical two-dimensional test, and horizontal two-dimensional test. Many data on the response characteristics of columns and the effect of the side support stiffness on the core vibration characteristics were derived from the basic tests

  9. Environmental and occupational exposure to benzene by analysis of breath and blood.

    Science.gov (United States)

    Perbellini, L; Faccini, G B; Pasini, F; Cazzoli, F; Pistoia, S; Rosellini, R; Valsecchi, M; Brugnone, F

    1988-05-01

    Benzene exposure of chemical workers was studied, during the entire workshift, by continuous monitoring of workplace benzene concentration, and 16 hours after the end of the workshift by the measurement of alveolar and blood benzene concentrations and excretion of urinary phenol. Exposure of hospital staff was studied by measuring benzene concentrations in the alveolar and blood samples collected during the hospital workshift. Instantaneous environmental air samples were also collected, at the moment of the biological sampling, for all the subjects tested. A group of 34 chemical workers showed an eight hour exposure to benzene, as a geometric mean, of 1.12 micrograms/l which corresponded, 16 hours after the end of the workshift, to a geometric mean benzene concentration of 70 ng/l in the alveolar air and 597 ng/l in the blood. Another group of 27 chemical workers (group A) turned out to be exposed to an indeterminable eight hour exposure to benzene that corresponded, the morning after, to a geometric mean benzene concentration of 28 ng/l in the alveolar air and 256 ng/l in the blood. The group of hospital staff (group B) had a benzene concentration of 14 ng/l in the alveolar air and 269 ng/l in the blood. Instantaneous environmental samples showed that in the infirmaries the geometric mean benzene concentration was 58 ng/l during the examination of the 34 chemical workers, 36 ng/l during the examination of the 27 chemical workers (group A), and 5 ng/l during the examination of the 19 subjects of the hospital staff (group B). Statistical analysis showed that the alveolar and blood benzene concentrations in the 34 workers exposed to 1.12 microgram/l of benzene differed significantly from those in groups A and B. It was found, moreover, that the alveolar and blood benzene concentrations were higher in the smokers in groups A and B but not in the smokers in the group of 34 chemical workers. The slope of the linear correlation between the alveolar and the instantaneous

  10. Geographical distribution of benzene in air in northwestern Italy and personal exposure.

    OpenAIRE

    Gilli, G.; Scursatone, E; Bono, R.

    1996-01-01

    Benzene is a solvent strictly related to some industrial activities and to automotive emissions. After the reduction in lead content of fuel gasoline, and the consequent decrease in octane number, an increase in benzene and other aromatic hydrocarbons in gasoline occurred. Therefore, an increase in the concentration of these chemicals in the air as primary pollutants and as precursors of photochemical smog could occur in the future. The objectives of this study were to describe the benzene ai...

  11. Experimental study of natural circulation circuit

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Wanderley F.; Su, Jian, E-mail: wlemos@lasme.coppe.ufrj.br, E-mail: sujian@lasme.coppe.ufrj.br [Coordenacao dos Programas de Pos-Graduacao de Engenharia (LASME/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Simulacao e Metodos Numericos; Faccini, Jose L.H., E-mail: faccini@ien.gov.br [Instituto de Engenharia Nuclear (LTE/IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. de Termo-Hidraulica Experimental

    2011-07-01

    This work presents an experimental study about fluid flows behavior in natural circulation, under conditions of single-phase flow. The experiment was performed through experimental thermal-hydraulic circuit built at IEN. This test equipment has performance similar to passive system of residual heat removal present in Advanced Pressurized Water Reactors (APWR). This experimental study aims to observing and analyzing the natural circulation phenomenon, using this experimental circuit that was dimensioned and built based on concepts of similarity and scale. This philosophy allows the analysis of natural circulation behavior in single-phase flow conditions proportionally to the functioning real conditions of a nuclear reactor. The experiment was performed through procedures to initialization of hydraulic feeding of primary and secondary circuits and electrical energizing of resistors installed inside heater. Power controller has availability to adjust values of electrical power to feeding resistors, in order to portray several conditions of energy decay of nuclear reactor in a steady state. Data acquisition system allows the measurement and monitoring of the evolution of the temperature in various points through thermocouples installed in strategic points along hydraulic circuit. The behavior of the natural circulation phenomenon was monitored by graphical interface on computer screen, showing the temperature evolutions of measuring points and results stored in digital spreadsheets. The results stored in digital spreadsheets allowed the getting of data to graphic construction and discussion about natural circulation phenomenon. Finally, the calculus of Reynolds number allowed the establishment for a correlation of friction in function of geometric scales of length, heights and cross section of tubing, considering a natural circulation flow throughout in the region of hot leg. (author)

  12. INVESTIGATION OF BENZENE OXIDE IN BONE MARROW AND OTHER TISSUES OF F344 RATS FOLLOWING METABOLISM OF BENZENE IN VITRO AND IN VIVO

    Science.gov (United States)

    This study examines the initial activation of benzene, exploring key aspects of its metabolism by measurement of benzene oxide (BO) and BO-protein adducts in vitro and in vivo. To assess the potential influence of various factors on the production of BO, microsomes were prepare...

  13. (Liquid + liquid) equilibria for benzene + cyclohexane + N,N-dimethylformamide + sodium thiocyanate

    International Nuclear Information System (INIS)

    Graphical abstract: On the left, the figure was phase diagram about the LLE date. On the right, the figure was about the effects of mass fraction of benzene in the raffinate phase to the selectivity(S) coefficient under different salt concentration. ■, the NaSCN and DMF in ratio of 5/95; • , the NaSCN and DMF in ratio of 10/90; ▴, the NaSCN and DMF in ratio of 15/85; ★, the NaSCN and DMF in ratio of 20/80; ▾, the NaSCN and DMF in ratio of 23/77. ♦, only DMF was used extractant (the selectivity coefficient was calculated by literature 17). w22, refer to the mass fraction of benzene in the raffinate phase (cyclohexane-rich phase). Highlights: • (Liquid + liquid) equilibrium for quaternary system was measured. • The components include benzene, cyclohexane, N,N-dimethylformamide, sodium thiocyanate. • The (liquid + liquid) equilibrium data can be well correlated by the NRTL model. • Separation of benzene and cyclohexane by NaSCN + DMF was discussed. -- Abstract: (Liquid + liquid) equilibrium (LLE) data for benzene + cyclohexane + N,N-dimethylformamide (DMF) + sodium thiocyanate (NaSCN) were measured experimentally at atmospheric pressure and 303.15 K. The selectivity coefficients from these LLE data were calculated and compared to those previously reported in the literature for the systems (benzene + cyclohexane + DMF) and (benzene + cyclohexane + DMF + KSCN). The NRTL equation was used to correlate the experimental data. The agreement between the predicted and experimental results was good. It was found that the selectivity coefficients of DMF + NaSCN for benzene ranged from 2.45 to 11.99. Considering the relatively high extraction capacity and selectivity for benzene, DMF + NaSCN may be used as a potential extracting solvent for the separation of benzene from cyclohexane

  14. 46 CFR 151.05-2 - Compliance with requirements for tank barges carrying benzene and benzene containing cargoes, or...

    Science.gov (United States)

    2010-10-01

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

  15. Benzene hemoglobin adducts in mice and rats: Characterization of formation and physiological modeling

    International Nuclear Information System (INIS)

    Benzene is a myelotoxin and a human leukemogen. Humans are exposed to this compound, both occupationally and environmentally. This study was conducted to determine whether formation of benzene-derived adducts with blood hemoglobin (Hb) can be used as a biomarker of exposure to benzene. B6C3F1 mice and F344/N rats were given 0.1 to 10,000 mumol [14C]benzene/kg body wt, orally. Twenty-four hours later, animals were euthanized, and globin was isolated from blood samples. The globin was analyzed by liquid scintillation spectrometry for the presence of [14C]benzene-derived adducts. Hb adduct formation was linear with respect to dose for amounts of up to 500 mumol [14C]benzene/kg body wt, for both rodent species. Within this linear dose-response range, mice formed adducts from [14C]benzene approximately 3.5 times less efficiently [0.022 +/- 0.010 (pmol adducts/mg globin)/(mumol/kg body wt dose)] than did rats [0.076 +/- 0.014 (pmol adducts)/(mumol/kg body wt dose)]. Benzene-derived Hb adducts also accumulated linearly when mice and rats were given up to three daily doses of 500 mumol [14C]benzene/kg body wt. These data were used to develop a physiological model for benzene-derived Hb adduct formation. Both first-order and saturable pathways for adduct formation were incorporated. The results showed that the model simulated the levels of Hb adducts in both mice and rats after oral exposures to benzene and predicted the levels of Hb adducts present after inhalation exposure. These studies suggest that Hb adducts might be useful biomarkers for human exposures to benzene

  16. A critique of the exposure assessment in the epidemiologic study of benzene-exposed workers in China conducted by the Chinese Academy of Preventive Medicine and the US National Cancer Institute.

    Science.gov (United States)

    Wong, O

    1999-12-01

    As reviewed in some detail in the present paper, workers employed in a wide variety of industries were included in the Chinese benzene study, and were exposed to not only benzene but also a wide range of other industrial chemicals. To attribute any or all health effects observed in the exposed cohort to benzene without examining other concomitant exposures is not appropriate. Although it was stated that one of the major objectives of the expanded study was to examine the effects of other risk factors, no such examination was made in any of the analyses in the expanded CAPM-NCI study. The CAPM-NCI study suffered from a number of limitations. One of the most serious limitations of the study involved the exposure estimates developed by the US NCI team. Comparing the assumptions used in the development of estimates and the exposure estimates themselves to actual data reported previously by the Chinese investigators revealed numerous inconsistencies and, in many cases, large discrepancies. It appeared that the exposure estimates were consistently lower than the actual exposure data. The so-called indirect validation conducted by the NCI team served no useful purpose, since by definition it could not validate the absolute values of the estimates. NCI was fully aware of some of the inadequacies of its exposure estimates. Although in a 1994 paper, the NCI team recognized that little confidence could be attached to the estimated (e.g., only 2% of the estimates for the time interval 1949-1959 and only 6% of the estimates prior to 1975 were rated in the high confidence category), the inadequacy of the estimates was never mentioned or discussed in any subsequent analyses or in the latest report (Hayes et al., 1998). Instead, the exposure of the workers was hailed as "well characterized" (Hayes et al., 1998). In conclusion both CAPM and NCI have made substantial efforts in studying the relationship between benzene exposure and various malignancies. Unfortunately, there were

  17. Angiographic technique in rabbits: an experimental study

    International Nuclear Information System (INIS)

    Objective: The rabbit is the most important experimental animal for the basic interventional research, which has displayed the essential value for the interventional experimental diagnosis and therapy in some tumor and vascular disease, while the angiography is the basic imaging examination for the related study. This research attempts to improve and to optimize the angiographic technique for the experimental rabbits, as well as to modify the hemostasis course in order to increase the success rate of angiographic study in rabbits. At the same time. a preliminary study of CTA and DSA in rabbits has also been made in order to get the relative experience. Methods: Fifteen New Zealand white rabbits were anesthetized, which was followed by CTA with the contrast injection through the ear vein catheterization. The diameters of the major blood vessels were measured and their shape and course were observed. An 18 G needle was used to puncture the blood vessels and a 4 F single bend catheter to perform the DSA examination. The groin area was dissected, the femoral artery and femoral vein were separated, and the catheter was inserted with Seldinger technique. For angiography examination, after the femoral artery was successfully punctured, DSA of the aortic arch, dorsal aorta, abdominal aorta, iliac artery, carotid artery, vertebral artery, celiac artery, anterior mesenteric artery and renal artery was carried out in proper sequence and the appearance of pertaining veins were also observed. For venography examination, after the femoral vein was successfully punctured, angiography of the posterior vena cava and pulmonary artery was performed successively. The femoral vein was pressed for a few minutes to stop bleeding, while the femoral artery bleeding was stanched by forceps, local wet compression with thrombin or surgical reconstruction of femoral artery sheath. Results: According to the diameter and shape of the major vessels, the combination of 18 G vascular puncture

  18. Exposure to benzene in urban workers: environmental and biological monitoring of traffic police in Rome

    OpenAIRE

    Crebelli, R; Tomei, F.; Zijno, A; Ghittori, S; M Imbriani; Gamberale, D; Martini, A.; Carere, A

    2001-01-01

    OBJECTIVES—To evaluate the contribution of traffic fumes to exposure to benzene in urban workers, an investigation on personal exposure to benzene in traffic police from the city of Rome was carried out.
METHODS—The study was performed from December 1998 to June 1999. Diffusive Radiello personal samplers were used to measure external exposures to benzene and alkyl benzenes during the workshift in 139 policemen who controlled medium to high traffic areas and in 63 office police. Moreover, as b...

  19. Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

    International Nuclear Information System (INIS)

    Highlights: → Enriched consortia were able to couple the anaerobic degradation of benzene to the reduction of humic acids. → Electron-equivalents derived from anaerobic benzene oxidation were highly recovered as reduced humic acids. → Several species from classes β-, δ- and γ-Proteobacteria were enriched during the anaerobic degradation of benzene. - Abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 μM of benzene were degraded, which corresponds to 279 ± 27 micro-electron equivalents (μEq) L-1, linked to the reduction of 619 ± 81 μEq L-1 of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two γ-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes β-, δ- and γ-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.

  20. Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes, Francisco J., E-mail: fjcervantes@ipicyt.edu.mx [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Mancilla, Ana Rosa; Toro, E. Emilia Rios-del [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Alpuche-Solis, Angel G.; Montoya-Lorenzana, Lilia [Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico)

    2011-11-15

    Highlights: {yields} Enriched consortia were able to couple the anaerobic degradation of benzene to the reduction of humic acids. {yields} Electron-equivalents derived from anaerobic benzene oxidation were highly recovered as reduced humic acids. {yields} Several species from classes {beta}-, {delta}- and {gamma}-Proteobacteria were enriched during the anaerobic degradation of benzene. - Abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 {mu}M of benzene were degraded, which corresponds to 279 {+-} 27 micro-electron equivalents ({mu}Eq) L{sup -1}, linked to the reduction of 619 {+-} 81 {mu}Eq L{sup -1} of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two {gamma}-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes {beta}-, {delta}- and {gamma}-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.

  1. Lymphocyte chromosome breakage in low benzene exposure among Indonesian workers

    Directory of Open Access Journals (Sweden)

    Dewi S. Soemarko

    2015-01-01

    Full Text Available Background: Benzene has been used in industry since long time and its level in environment should be controled. Although environmental benzene level has been controlled to less than 1 ppm, negative effect of benzene exposure is still observed, such as chromosome breakage. This study aimed to know the prevalence of lymphocyte chromosome breakage and the influencing factors among workers in low level benzene exposure.Methods: This was a cross sectional study in oil & gas industry T, conducted between September 2007 and April 2010. The study subjects consisted of 115 workers from production section and head office. Data on type of work, duration of benzene exposure, and antioxidant consumption were collected by interview as well as observation of working process. Lymphocyte chromosome breakage was examined by banding method. Analysis of relationship between chromosome breakage and risk factors was performed by chi-square and odd ratio, whereas the role of determinant risk factors was analyzed by multivariate forward stepwise.Results: Overall lymphocyte chromosome breakage was experieced by 72 out of 115 subjects (62.61%. The prevalence among workers at production section was 68.9%, while among administration workers was 40% (p > 0.05. Low antioxidant intake increases the risk of chromosome breakage (p = 0.035; ORadjusted = 2.90; 95%CI 1.08-7.78. Other influencing factors are: type of work (p = 0,10; ORcrude = 3.32; 95% CI 1.33-8.3 and chronic benzene exposure at workplace (p = 0.014; ORcrude = 2.61; 95% CI 1.2-5.67, while the work practice-behavior decreases the lymphocyte chromosome breakage (p = 0.007; ORadjusted = 0.30; 95% CI 0.15-0.76.Conclusion: The prevalence of lymphocyte chromosome breakage in the environment with low benzene exposure is quite high especially in production workers. Chronic benzene exposure in the workplace, type of work, and low antioxidant consumption is related to lymphocyte chromosome breakage. Thus, benzene in the

  2. Experimental study of diffusion charging of aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Pui, D.Y.H.

    1976-03-01

    The electrical charging of aerosol particles by unipolar gaseous ions was studied theoretically and experimentally. The primary objective of the study was to make precise determinations of the aerosol particle charge under various conditions of charging and to compare the experimental results with those predicted by theory. Experiments were performed using monodisperse oleic acid aerosols generated by a vibrating orifice generator, monodisperse NaCl and DOP (di-octyl phthalate) aerosols generated by an electrostatic classification method, and sulfuric acid aerosols generated by the photo-chemical conversion of gaseous SO/sub 2/ in the smog chamber. The experiments covered a particle size range of 0.0075 ..mu..m to 5.04 ..mu..m diameter. The corresponding range in Knudsen number (Kn = lambda/sub i//a, lambda/sub i/ = mean free path of ions, a = particle radius) was from 0.0056 to 3.86. The charging parameter, n/sub 0/t, was varied between 2.56 x 10/sup 6/ to 5.1 x 10/sup 7/ ion-s/cc, where n/sub 0/ is the concentration of ions and t is the charging time. Comparisons of the results with available aerosol charging theories indicate that there is reasonable agreement between the theory and experiment in the continuum regime (Kn << 1) where the classical Fuchs--Pluvinage equation is expected to apply. However, in the free molecular (Kn >> 1) and the transition regimes (Kn approx. or equal to 1), where the ion mean free path is no longer small in comparison with particle size, there is considerable discrepancy between the experimental data and available charging theories. A semi-empirical equation was developed which agrees well with the experimental data over the entire range of particle size and charging parameters covered in the experiments. Theoretical results are presented showing the distribution of charges on the particles as a function of particle size and the charging parameter n/sub 0/t. 70 figures, 24 tables, 112 references. (auth)

  3. Low-dose metabolism of benzene in humans: science and obfuscation.

    Science.gov (United States)

    Rappaport, Stephen M; Kim, Sungkyoon; Thomas, Reuben; Johnson, Brent A; Bois, Frederic Y; Kupper, Lawrence L

    2013-01-01

    Benzene is a ubiquitous air pollutant that causes human leukemia and hematotoxic effects. Although the mechanism by which benzene causes toxicity is unclear, metabolism is required. A series of articles by Kim et al. used air and biomonitoring data from workers in Tianjin, China, to investigate the dose-specific metabolism (DSM) of benzene over a wide range of air concentrations (0.03-88.9 p.p.m.). Kim et al. concluded that DSM of benzene is greatest at air concentrations American Petroleum Institute to fund a study by Price et al. to reanalyze the original data. Although their formal 'reanalysis' reproduced Kim's finding of enhanced DSM at sub-p.p.m. benzene concentrations, Price et al. argued that Kim's methods were inappropriate for assigning benzene exposures to low exposed subjects (based on measurements of urinary benzene) and for adjusting background levels of metabolites (based on median values from the 60 lowest exposed subjects). Price et al. then performed uncertainty analyses under alternative approaches, which led them to conclude that '… the Tianjin data appear to be too uncertain to support any conclusions …' regarding the DSM of benzene. They also argued that the apparent low-dose metabolism of benzene could be explained by 'lung clearance.' In addressing these criticisms, we show that the methods and arguments presented by Price et al. are scientifically unsound and that their results are unreliable. PMID:23222815

  4. Determination of benzene in different food matrices by distillation and isotope dilution HS-GC/MS

    International Nuclear Information System (INIS)

    Benzene is classified by the IARC as carcinogenic to humans. Several sources may contribute for the occurrence of benzene in foods, such as, environmental contamination and the reaction of benzoate salts with ascorbic acid (naturally present or added as food additives). Matrix effect on benzene recovery (e.g. in fatty foods) and artefactual benzene formation from benzoate during analysis in the presence of ascorbate are some of the challenges presented when determining benzene in a wide range of foodstuffs. Design of experiment (DOE) was used to determine the most important variables in benzene recovery from headspace GC/MS. Based on the results of the DOE, a versatile method for the extraction of benzene from all kind of food commodities was developed. The method which consisted of distillation and isotope dilution HS-GC/MS was in-house validated. Artefactual benzene was prevented by addition of a borate buffer solution (pH 11) under distillation conditions. The method presented in this study allows the use of a matrix-independent calibration with detection limits below the legal limit established by the European Council for benzene in drinking water (1 μg L-1).

  5. Slow Neutron Scattering by Benzene

    International Nuclear Information System (INIS)

    We have calculated the scattering of slow neutrons by the benzene molecule. The calculations are carried out within the framework of the time dependent formalism of Zemach and Glauber. Detailed account is taken of the effects of the molecular vibrations on the neutron scattering. Among the results explicitly calculated are the slow neutron total scattering cross-section as a function of energy and the energy angular distribution of singly scattered sections. (author)

  6. A laboratory experimental setup for photo-absorption studies using synchrotron radiation

    CERN Document Server

    Shastri, A; Saraswati, P; Sunanda, K

    2002-01-01

    The photophysics beamline, which is being installed at the 450 MeV Synchrotron Radiation Source (SRS), Indus-l, is a medium resolution beamline useful for a variety of experiments in the VUV region viz. 500-2000 A. One of the major applications of this beamline is gas-phase photo-absorption studies. An experimental set up to be used for these experiments was designed, developed and tested in our laboratory. The setup consists of a high vacuum absorption cell, 1/4 m monochromator and detection system. For the purpose of testing, xenon and tungsten continuum sources were used and absorption spectra were recorded in the UV region. This setup was used to record the absorption spectrum of a few molecules like acetone, ammonia, benzene, formaldehyde and acetaldehyde in order to evaluate the performance of the experimental system which will subsequently be used with the photophysics beamline. Details of the design, fabrication and testing of the absorption cell and experimental procedures are presented in this repor...

  7. Experimental study on low pressure flow instability

    International Nuclear Information System (INIS)

    The experiment was performed on the test loop (HRTL-5), which simulates the geometry and system design of the 5 MW reactor. The flow behavior for a wide range of inlet subcooling, in which the flow undergoes from single phase to two phase, is described in a natural circulation system at low pressure (p = 0.1, 0.24 MPa). Several kinds of flow instability, e.g. subcooled boiling instability, subcooled boiling induced flashing instability, pure flashing instability as well as flashing coupled density wave instability and high frequency flow oscillation, are investigated. The mechanism of flashing and flashing concerned flow instability, which has never been studied well in this field, is especially interpreted. The experimental results show that, firstly, for a low pressure natural circulation system the two phase flow is unstable in most of inlet subcooling conditions, the two phase stable flow can only be reached at very low inlet subcooling; secondly, at high inlet subcooling the flow instability is dominated by subcooled boiling in the heated section, and at middle inlet subcooling is dominated by void flashing in the adiabatic long riser; thirdly, in two phase stable flow region the condition for boiling out of the core, namely, single phase flow in the heated section, two phase flow in the riser due to vapor flashing, can be realized. The experimental results are very important for the design and accident analysis of the vessel and swimming pool type natural circulation nuclear heating reactor. (7 refs., 10 figs., 1 tab.)

  8. Experimental models to study cholangiocyte biology

    Institute of Scientific and Technical Information of China (English)

    Pamela S. Tietz; Xian-Ming Chen; Ai-Yu Gong; Robert C. Huebert; Anatoliy Masyuk; Tatyana Masyuk; Patrick L. Splinter; Nicholas F. LaRusso

    2002-01-01

    Cholangiocytes-the epithelial cells which line the bileducts-are increasingly recognized as importanttransporting epithelia actively involved in the absorptionand secretion of water, ions, and solutes. Thisrecognition is due in part to the recent development ofnew experimental models. New biologic concepts haveemerged including the identification and topography ofreceptors and flux proteins on the apical and/orbasolateral membrane which are involved in the molecularmechanisms of ductal bile secretion. Individually isolatedand/or perfused bile duct units from livers of rats andmice serve as new, physiologically relevant in vitromodels to study cholangiocyte transport. Biliary treedimensions and novel insights into anatomic remodeling ofproliferating bile ducts have emerged from three-dimensional reconstruction using CT scanning andsophisticated software. Moreover, new pathologicconcepts have arisen regarding the interaction ofcholangiocytes with pathogens such as Cryptosporidiumparvum. These concepts and associated methodologiesmay provide the framework to develop new therapies for the cholangiopathies, a group of important hepatobiliarydiseases in which cholangiocytes are the target cell.Tietz PS, Chen XM, Gong AY, Huebert RC, Masyuk A, MasyukT, Splinter PL, LaRusso NF. Experimental models to studycoholangiocyte biology.

  9. Experimental studies to calibrate unsaturated flow models

    International Nuclear Information System (INIS)

    Many aspects of the work related to design and performance assessment of the proposed High Level Nuclear Waste Repository at Yucca Mountain are based upon estimates of moisture migration in the surrounding formations. These estimates are usually made using computer codes that have varying degrees of validation. Since most of the moisture flows are in highly nonhomogeneous media and are unsaturated, the development of experimental data for validating models is a difficult task. Work is described that has been designed to serve as a laboratory calibration of numerical models for unsaturated flow studies. The experiment size is configured large enough that the assumptions applicable to most numerical models should apply, but the size is small enough that the test section can be characterized well and accurately monitored. A large piece of consolidated and fractured medium is used for the main test element. In addition to careful assessment of flows in and out, the moisture content at various locations along the element is monitored. Both electromagnetic and ultrasonic techniques are used in our experiments for the latter estimates. The general experimental method, control system, and data acquisition approach are described

  10. Experimental Study on Unconfined Vapor Cloud Explosion

    Institute of Scientific and Technical Information of China (English)

    毕明树; ABULITI; Abudula

    2003-01-01

    An experimental system was setup to study the pressure field of unconfined vapor cloud explosions.The semi-spherical vapor clouds were formed by slotted 0.02mm polyethylene film.In the Center of the cloud was an ignition electrode that met ISO6164"Explosion protection System" and NFPA68 "Guide for Venting of Deflagrations". A data-acquisition system,with dymame responding time less than 0.001s with 0.5% accuracy,recorded the pressure-time diagram of acetylene-air mixture explosion with stoichiometrical ratio.The initial cloud diameters varied from 60cm to 300cm.Based on the analysis of experimental data,the quantitative relationship is obtained for the cloud explosion pressure,the cloud radius and the distance from ignition point .Present results provide a useful way to evaluate the building damage caused by unconfined vapor cloud explosions and to determine the indispensable explosion grade in the application of multi-energy model.

  11. Experimental studies on ozonation of ethylenethiourea

    Institute of Scientific and Technical Information of China (English)

    Xinyu Dong; Junwang Meng; Bo Yang; Yang Zhang; Jie Gan; Xi Shu; Jinian Shu

    2011-01-01

    The experimental study on ozonation of ethylenethiourea (ETU) is conducted. The reaction of gas-phase ETU with 0.63 × l06 mol/L ozone is carried out in a 200-L reaction chamber. The secondary organic aerosol (SOA) resulted from the ozonation of gas-phase ETU is observed with a scanning mobility particle size (SMPS). The rapid exponential growth of SOA reveals that the atmospheric lifetime of ETU vapor towards ozone reaction is less than four days. The ozonation of dry ETU particles, ETU-contained water droplets and ETU aqueous solution is investigated with a vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer (VUVATOFMS). The formation of 2-imidazoline is observed in the ozonation of dry ETU particles and ETU-contained water droplets. The formation of 2-imidazoline and ethylenerea is observed in the ozonation of ETU aqueous solution.

  12. Cognitive network structure: an experimental study

    CERN Document Server

    Guazzini, Andrea; Bagnoli, Franco; Carletti, Timoteo; Grotto, Rosapia Lauro

    2012-01-01

    In this paper we present first experimental results about a small group of people exchanging private and public messages in a virtual community. Our goal is the study of the cognitive network that emerges during a chat seance. We used the Derrida coefficient and the triangle structure under the working assumption that moods and perceived mutual affinity can produce results complementary to a full semantic analysis. The most outstanding outcome is the difference between the network obtained considering publicly exchanged messages and the one considering only privately exchanged messages: in the former case, the network is very homogeneous, in the sense that each individual interacts in the same way with all the participants, whilst in the latter the interactions among different agents are very heterogeneous, and are based on "the enemy of my enemy is my friend" strategy. Finally a recent characterization of the triangular cliques has been considered in order to describe the intimate structure of the network. E...

  13. Free will and consciousness: experimental studies.

    Science.gov (United States)

    Shepherd, Joshua

    2012-06-01

    What are the folk-conceptual connections between free will and consciousness? In this paper I present results which indicate that consciousness plays central roles in folk conceptions of free will. When conscious states cause behavior, people tend to judge that the agent acted freely. And when unconscious states cause behavior, people tend to judge that the agent did not act freely. Further, these studies contribute to recent experimental work on folk philosophical affiliation, which analyzes folk responses to determine whether folk views are consistent with the view that free will and determinism are incompatible (incompatibilism) or with the opposite view (compatibilism). Conscious causation of behavior tends to elicit pro-free will judgments, even when the causation takes place deterministically. Thus, when controlling for consciousness, many folk seem to be compatibilists. However, participants who disagree with the deterministic or cognitive scientific descriptions given of human behavior tend to give incompatibilist responses. PMID:22480780

  14. [Brackets and friction in orthodontics: experimental study].

    Science.gov (United States)

    Ben Rejeb Jdir, Saloua; Tobji, Samir; Turki, Wiem; Dallel, Ines; Khedher, Nedra; Ben Amor, Adel

    2015-09-01

    Many authors have been involved in developing brackets in order to improve the quality, stability, speed and efficiency of orthodontic treatment. In order to reduce friction between bracket and archwire, new therapeutic approaches have been devised based on novel technologies. Among these innovative techniques, self-ligating brackets are increasingly popular. SLBs can be classified into several categories according to their mode of action and their materials. We performed an experimental study to compare the friction forces generated during the sliding of orthodontic archwires made from various alloys through conventional and self-ligating brackets. Results show the favorable influence of SLBs, compared to conventional systems using elastomeric or metal ligatures, on the level of friction, particularly when shape-memory Ni-Ti archwires are used. PMID:26370596

  15. Experimental Study on Scours Downstream of Floodgates

    Institute of Scientific and Technical Information of China (English)

    张玮; 陈锡林; 徐金环; 李国臣; 王志谦

    2000-01-01

    The river reach downstream of a floodgate at the estuary of the Xinyihe River is about 1.3km long, and the riverbed is composed of clotty clay. In the experiment, soil samples are taken from the construction site, and the incipient velocity is determined in a laboratory flume, and it is used to design the scour model and to select model sand material. The experimental results show that scours below the floodgate is unavoidable due to large discharge and low tidal level. Scours is caused by two factors: the rapid flow passing though the floodgate and the water drop near the river mouth during low tide, and the scour below the floodgate is more critical to the structural design. It is suggested that anti-scour walls should be used instead of riprap. The ideas and methods adopted in the experiment can be used as reference in the study on river scour under similar conditions.

  16. Simulation and Experimental Studies on Composite Beams

    Directory of Open Access Journals (Sweden)

    M. Abhinay

    2014-09-01

    Full Text Available A composite beam a one dimensional structure or a rod all of them are sectional dimensions in which width and height are much smaller in comparison to the structure. In structural applications longer beams are more frequently used. In this work a composite beam is manufactured with glass and epoxy combination. And stress analysis is carried out using derived analytical expressions. This research work carried out will enable to determine the beam strength due to bending loads. The importance of fiber reinforcement in the manufacturing of the beam is studied in terms of bending strength of the beam. Mat lab codes are generated to implement analytical equations of the composite beam. The analytical results are validated by performing experiments on composite beams. In this investigation, two different composite beams have been tested and compared the experimental results with the analytical results.

  17. Collision lifetimes of polyatomic molecules at low temperatures: Benzene–benzene vs benzene–rare gas atom collisions

    International Nuclear Information System (INIS)

    We use classical trajectory calculations to study the effects of the interaction strength and the geometry of rigid polyatomic molecules on the formation of long-lived collision complexes at low collision energies. We first compare the results of the calculations for collisions of benzene molecules with rare gas atoms He, Ne, Ar, Kr, and Xe. The comparison illustrates that the mean lifetimes of the collision complexes increase monotonically with the strength of the atom–molecule interaction. We then compare the results of the atom–benzene calculations with those for benzene–benzene collisions. The comparison illustrates that the mean lifetimes of the benzene–benzene collision complexes are significantly reduced due to non-ergodic effects prohibiting the molecules from sampling the entire configuration space. We find that the thermally averaged lifetimes of the benzene–benzene collisions are much shorter than those for Xe with benzene and similar to those for Ne with benzene

  18. CH/pi interaction between benzene and hydrocarbons having six carbon atoms in their binary liquid mixtures.

    Science.gov (United States)

    Kasahara, Yasutoshi; Suzuki, Yuji; Kabasawa, Aino; Minami, Hideyuki; Matsuzawa, Hideyo; Iwahashi, Makio

    2010-01-01

    Molecular interactions between benzene and hydrocarbons having six carbon atoms, such as hexane, cyclohexane and 1-hexene in their binary liquid mixtures were studied through the measurements of density, viscosity, self-diffusion coefficient, (13)C NMR spin-lattice relaxation time and (1)H NMR chemical shift. CH/pi attraction between hexane and benzene in their binary mixture was observed in a relatively benzene rich region, whereas a special attractive interaction was not observed between cyclohexane and benzene. On the other hand, 1-hexene and benzene in their binary mixtures were characteristic in their self-diffusion coefficient behaviors: 1-hexene more strongly attract benzene not only by the CH/pi attraction but also probably by the p/p interaction between the double bond in 1-hexene and the p-electron in benzene ring. PMID:20032596

  19. The past suppression of industry knowledge of the toxicity of benzene to humans and potential bias in future benzene research.

    Science.gov (United States)

    Infante, Peter F

    2006-01-01

    Petrochemical industry representatives often withhold information and misinterpret positive evidence of toxicity of benzene, even from their own research, also discouraging or delaying disclosure of findings of adverse effects to the public. They now appear to be attempting to influence study results in industry's favor by offering predetermined conclusions about study results as part of an effort to draw financial support for the studies. The American Petroleum Institute is currently raising funds for benzene research being conducted in China for which it has already announced the intended conclusions. PMID:16967835

  20. Bee algorithm and adaptive neuro-fuzzy inference system as tools for QSAR study toxicity of substituted benzenes to Tetrahymena pyriformis.

    Science.gov (United States)

    Zarei, Kobra; Atabati, Morteza; Kor, Kamalodin

    2014-06-01

    A quantitative structure-activity relationship (QSAR) was developed to predict the toxicity of substituted benzenes to Tetrahymena pyriformis. A set of 1,497 zero- to three-dimensional descriptors were used for each molecule in the data set. A major problem of QSAR is the high dimensionality of the descriptor space; therefore, descriptor selection is one of the most important steps. In this paper, bee algorithm was used to select the best descriptors. Three descriptors were selected and used as inputs for adaptive neuro-fuzzy inference system (ANFIS). Then the model was corrected for unstable compounds (the compounds that can be ionized in the aqueous solutions or can easily metabolize under some conditions). Finally squared correlation coefficients were obtained as 0.8769, 0.8649 and 0.8301 for training, test and validation sets, respectively. The results showed bee-ANFIS can be used as a powerful model for prediction of toxicity of substituted benzenes to T. pyriformis. PMID:24638918

  1. Experimental and theoretical study of reflux condensation

    Energy Technology Data Exchange (ETDEWEB)

    Bakke, Knut

    1997-12-31

    This thesis studies the separation of gas mixtures in a reflux condenser. also called a dephlegmator. Reflux condensation is separation of a gas mixture, in reflux flow with condensing liquid, under continuous heat removal. A numerical model of a dephlegmator for binary mixtures was developed. The model may readily be extended to multi-component mixtures, as the solution method is based on a matrix solver. Separation of a binary mixture in a reflux condenser test rig is demonstrated. The test facility contains a single-tube test section that was designed and built as part of the project. Test mixtures of propane and n-butane were used, and a total of 15 experiments are reported. Limited degree of separation was achieved due to limited heat transfer area and narrow boiling point range of the test mixture. The numerical model reproduces the experimental data within reasonable accuracy. Deviation between calculated and measured properties is less than 6% of the measured temperature and less than 5% of the measured flow rate. The model is based on mechanistic models of physical processes and is not calibrated or tuned to fit the experimental data. The numerical model is applied to a number of separation processes. These case studies show that the required heat transfer area increases rapidly with increments in top product composition (light component). Flooding limits the amount of reflux liquid. The dephlegmator is suitable for separation of feed mixtures that are rich in light components. The gliding temperature in the dephlegmation process enables utilization of top product as refrigerant, with subsequent energy saving as a result. 61 refs., 50 figs., 34 tabs.

  2. A lack of consensus in the literature findings on the removal of airborne benzene by houseplants: Effect of bacterial enrichment

    Science.gov (United States)

    Sriprapat, Wararat; Strand, Stuart E.

    2016-04-01

    Removal rates of benzene and formaldehyde gas by houseplants reported by several laboratories varied by several orders of magnitude. We hypothesized that these variations were caused by differential responses of soil microbial populations to the high levels of pollutant used in the studies, and tested responses to benzene by plants and soils separately. Five houseplant species and tobacco were exposed to benzene under hydroponic conditions and the uptake rates compared. Among the test plants, Syngonium podophyllum and Chlorophytum comosum and Epipremnum aureum had the highest benzene removal rates. The effects of benzene addition on populations of soil bacteria were determined using reverse transcription quantitative PCR (RT-qPCR) assays targeting microbial genes involved in benzene degradation. The total bacterial population increased as shown by increases in the levels of eubacteria 16S rRNA, which was significantly higher in the high benzene incubations than in the low benzene incubations. Transcripts (mRNA) of genes encoding phenol monooxygenases, catechol-2,3-dioxygenase and the housekeeping gene rpoB increased in all soils incubated with high benzene concentrations. Therefore the enrichment of soils with benzene gas levels typical of experiments with houseplants in the literature artificially increased the levels of total soil bacterial populations, and especially the levels and activities of benzene-degrading bacteria.

  3. Impact of a new gasoline benzene regulation on ambient air pollutants in Anchorage, Alaska

    Science.gov (United States)

    Yano, Yuriko; Morris, Stephen S.; Salerno, Christopher; Schlapia, Anne M.; Stichick, Mathew

    2016-05-01

    The purpose of this study was to quantify the impact of a new U.S. Environmental Protection Agency (EPA) standard that limits the amount of benzene allowed in gasoline on ambient benzene concentrations. This new standard, together with two companion regulations that limit cold-temperature automotive emissions and the permeability of portable fuel containers, was expected to lower the levels of ambient benzene and other volatile organic compounds (VOCs) nationwide. In this study the impact of the gasoline benzene standard was evaluated in Anchorage, Alaska in a two-phase ambient air monitoring study conducted before and after the new gasoline standard was implemented. Gasoline sold by Anchorage retailers was also evaluated in each phase to determine the content of benzene and other gasoline components. The average benzene content in Anchorage gasoline was reduced by 70%, from 5.05% (w/w) to 1.53% (w/w) following the implementation of the standard. The annual mean ambient benzene concentration fell by 51%, from 0.99 ppbv in Phase 1 to 0.49 ppbv in Phase 2. Analysis suggests the change in gasoline benzene content alone reduced benzene emissions by 46%. The changes in toluene, ethylbenzene, and xylene content in gasoline between Phase 1 and 2 were relatively small and the differences in the mean ambient concentrations of these compounds between phases were modest. Our results suggest that cold winter communities in high latitude and mountainous regions may benefit more from the gasoline benzene standard because of high benzene emissions resulting from vehicle cold start and a tendency to develop atmospheric stagnation conditions in the winter.

  4. Theoretical and experimental studies of elementary physics

    International Nuclear Information System (INIS)

    The various components of the high-energy physics research program at the University of Rochester are presented. (I)Fixed-target experimentation at FNAL includes studies of direct photon production by p and π on H, Be, and Cu, and hybrid mesons and other physics issues in Coulomb excitation at high energies. (II)The status of the GEM (Gammas, Electrons, and Muons) Experiment at the SSC is given. (III)The D-Zero experiment at FNAL is reviewed. (IV)Deep inelastic lepton--nucleon scattering experiments are summarized: electron scattering experiments at SLAC, FNAL neutrino quad triplet runs, FNAL neutrino sign selected experiments, and SDC cosmic ray test and test beam calibration. (V)Studies of nonlinear QED at SLAC concentrated on a study of QED at critical field strength in intense laser--high-energy electron collisions. (VI)Development work on the Collider Detector at Fermilab (CDF) emphasized the CDF silicon vertex detector, the end plug calorimeter, and the SDC tile/fiber calorimetry. (VII)The theoretical physics effort is sketched

  5. An experimental study of nerve bypass graft

    Institute of Scientific and Technical Information of China (English)

    XU Jie; LI Xue-shi

    2008-01-01

    Objective: To study the use of a nerve "bypass" graft as a possible alternative to neurolysis or segmental resection with interposition grafting in the treatment of neuroma-in-continuity. Methods: A sciatic nerve crush injury model was established in the Sprague-Dawley rat by compression with a straight hemostatic forceps. Epineurial windows were created proximal and distal to the injury site. An 8-mm segment of radial nerve was harvested and coaptated to the sciatic nerve at the epineurial window sites proximal and distal to the compressed segment (bypass group). A sciatic nerve crush injury without bypass served as a control. Nerve conduction studies were performed over an 8-week period. Sciatic nerves were then harvested and studied under transmission electron microscopy. Myelinated axon counts were obtained. Results: Nerve conduction velocity was significantly faster in the bypass group than in the control group at 8 weeks (63.57 m/s±5.83 m/s vs. 54.88 m/s±4.79m/s, P<0.01). Myelinated axon counts in distal segments were found more in the experimental sciatic nerve than in the control sciatic nerve. Significant axonal growth was noted in the bypass nerve segment itself. Conclusion: Nerve bypass may serve to augment peripheral axonal growth while avoiding further loss of the native nerve.

  6. Experimental study on transient boiling heat transfer

    International Nuclear Information System (INIS)

    Boiling phenomena can be found in the everyday life, thus a lot of studies are devoted to them, especially in steady state conditions. Transient boiling is less known but still interesting as it is involved in the nuclear safety prevention. In this context, the present work was supported by the French Institute of Nuclear Safety (IRSN). In fact, the IRSN wanted to clarify what happens during a Reactivity-initiated Accident (RIA). This accident occurs when the bars that control the nuclear reactions break down and a high power peak is passed from the nuclear fuel bar to the surrounding fluid. The temperature of the nuclear fuel bar wall increases and the fluid vaporises instantaneously. Previous studies on a fuel bar or on a metal tube heated by Joule effect were done in the past in order to understand the rapid boiling phenomena during a RIA. However, the measurements were not really accurate because the measurement techniques were not able to follow rapid phenomena. The main goal of this work was to create an experimental facility able to simulate the RIA boiling conditions but at small scale in order to better understand the boiling characteristics when the heated-wall temperature increases rapidly. Moreover, the experimental set-up was meant to be able to produce less-rapid transients as well, in order to give information on transient boiling in general. The facility was built at the Fluid-Mechanics Institute of Toulouse. The core consists of a metal half-cylinder heated by Joule effect, placed in a half-annulus section. The inner half cylinder is made of a 50 microns thick stainless steel foil. Its diameter is 8 mm, and its length 200 mm. The outer part is a 34 mm internal diameter glass half cylinder. The semi-annular section is filled with a coolant, named HFE7000. The configuration allows to work in similarity conditions. The heated part can be place inside a loop in order to study the flow effect. The fluid temperature influence is taken into account as

  7. FORMATION OF HEMOGLOBIN AND ALBUMIN ADDUCTS OF BENZENE OXIDE IN MOUSE, RAT, AND HUMAN BLOOD

    Science.gov (United States)

    Little is known about the formation and disposition of benzene oxide (BO), the initial metabolite arising from oxidation of benzene by cytochrome P450. In this study, reactions of BO with hemoglobin (Hb) and albumin (Alb) were investigated in blood from B6C3F1 mice, F344 rats, ...

  8. Genotoxic and histotoxic effects of air pollutants at a benzene station on albino rats

    Directory of Open Access Journals (Sweden)

    Mohamed Abousalem

    2014-02-01

    Conclusions: The findings of the present study indicated that benzene exposure may lead to toxic effects including, genotoxicities and histotoxicities. In order to minimize the predicted toxic effect of occupational exposure to benzene the strict protective measures should be put in consideration. [Int J Basic Clin Pharmacol 2014; 3(1.000: 144-150

  9. Hydrogenation of Benzene over Mo2C/Al2O3 Catalyst

    Institute of Scientific and Technical Information of China (English)

    Zhang Jing; Wu Weicheng

    2008-01-01

    The process of benzene hydrogenation over Mo2C catalyst has been studied.Mo2C was the active phase in benzene hydrogenation.The major problem with the metal carbides was their poor stability due to deactivation by carbon deposition.

  10. Differential susceptibility of rats and guinea pigs to the ototoxic effects of ethyl benzene

    NARCIS (Netherlands)

    Cappaert, NLM; Klis, SFL; Muijser, H; Kulig, BM; Ravensberg, LC; Smoorenburg, GF

    2002-01-01

    The present study was designed to compare the ototoxic effects of volatile ethyl benzene in guinea pigs and rats. Rats showed deteriorated auditory thresholds in the mid-frequency range, based on electrocochleography, after 550-ppm ethyl benzene (8 h/day, 5 days). Outer hair cell (OHC) loss was foun

  11. Theoretical and Experimental Studies of Radiative Shocks

    Science.gov (United States)

    Michaut, C.; Vinci, T.; Boireau, L.; Koenig, M.; Bouquet, S.; Benuzzi-Mounaix, A.; Osaki, N.; Herpe, G.; Falize, E.; Loupias, B.; Atzeni, S.

    2007-01-01

    This paper deals with the radiative shock from both theoretical and numerical points of view. It is based on the whole experimental results obtained at Laboratoire d'Utilisation des Lasers Intenses (LULI, École Polytechnique). Radiative shocks are high-Mach number shocks with a strong coupling between radiation and hydrodynamics which leads to a structure governed by a radiative precursor. These shocks are involved in various astrophysical systems: stellar accretion shocks, pulsating stars, interaction between supernovae and the interstellar medium. In laboratory, these radiative shocks are generated using high power lasers. New diagnostics have been implemented to study the geometrical shape of the shock and the front shock density. Data were obtained varying initial conditions for different laser intensities and temperature. The modeling of these phenomena is mainly performed through numerical simulations (1D and 2D) and analytical studies. We exhibit results obtained from several radiative hydrodynamics codes. As a result, it is possible to discuss about the influence of the geometry and physical parameters introduced in the 1D and 2D models.

  12. Benzene/nitrous oxide flammability in the precipitate hydrolysis process

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, R A [Du Pont de Nemours (E.I.) and Co., Aiken, SC (USA). Savannah River Lab.

    1989-09-18

    The HAN (hydroxylamine nitrate) process for destruction of nitrite in precipitate hydrolysis produces nitrous oxide (N2O) gas as one of the products. N2O can form flammable mixtures with benzene which is also present due to radiolysis and hydrolysis of tetraphenylborate. Extensive flame modeling and explosion testing was undertaken to define the minimum oxidant for combustion of N2O/benzene using both nitrogen and carbon dioxide as diluents. The attached memorandum interprets and documents the results of the studies.

  13. Experimental Study of Gas Hydrate Dynamics

    Science.gov (United States)

    Fandino, O.; Ruffine, L.

    2011-12-01

    Important quantities of methane and other gases are trapped below the seafloor and in the permafrost by an ice-like solid, called gas hydrates or clathrate hydrates. The latter is formed when water is mixing with different gases at high pressures and low temperatures. Due to a their possible use as a source of energy [1] or the problematic related to flow assurance failure in pipelines [2] the understanding of their processes of formation/destabilisation of these structures becomes a goal for many laboratories research as well as industries. In this work we present an experimental study on the stochastic behaviour of hydrate formation from a bulk phase. The method used here for the experiments was to repeat several time the same hydrate formation procedure and to notice the different from one experiment to another. A variable-volume type high-pressure apparatus with two sapphire windows was used. This device, already presented by Ruffine et al.[3], allows us to perform both kinetics and phase equilibrium measurements. Three initial pressure conditions were considered here, 5.0 MPa, 7.5 MPa and 10.0 MPa. Hydrates have been formed, then allowed to dissociate by stepwise heating. The memory effect has also been investigated after complete dissociation. It turned out that, although the thermodynamics conditions of formation and/or destabilization were reproducible. An attempt to determine the influence of pressure on the nucleation induction time will be discussed. References 1. Sum, A. K.; Koh, C. A.; Sloan, E. D., Clathrate Hydrates: From Laboratory Science to Engineering Practice. Industrial & Engineering Chemistry Research 2009, 48, 7457-7465. 2. Sloan, E. D., A changing hydrate paradigm-from apprehension to avoidance to risk management. Fluid Phase Equilibria 2005, 228, 67-74. 3. Ruffine, L.; Donval, J. P.; Charlou, J. L.; Cremière, A.; Zehnder, B. H., Experimental study of gas hydrate formation and destabilisation using a novel high-pressure apparatus. Marine

  14. Theoretical and experimental studies on the foundation theoretical and experimental studies on the foundation of mesomechanics

    Science.gov (United States)

    Chudnovsky, A.; Wu, S.

    1992-06-01

    The report summarizes a closely coupled experimental and theoretical investigation of various stages of Fracture Process: (1) accumulation of 'damage' on submicroscopical and microscopical scales leading to crack initiation; (2) slow (subcritical) crack growth and an evolution of the damage zone; (3) transition to dynamic crack growth and the catastrophic failure. The experimental part of the program is focused on the observation and quantitative characterization of damage preceding and accompanying crack initiation and growth. A special experimental setup for studying the fracture process under variable stress field is reported in Chapter 2. A leading role of crack-damage interaction in fracture process is well documented. A new formalism for solution of crack-microcrack array interaction problem and its successful implementation in the evaluation of crack layer driving forces is presented in Chapter 3. A new model of the process zone, which generalizes the well-known Dagdale-Barenblatt model is presented in Chapter 4. A new measure for material toughness and the prediction of R-curve behavior illustrate the practical application of our model. Experimental examinations of our model under various test conditions are reported in Chapters 4, 5 and 6. The development of the constitutive equations for Crack Layer evolution and their experimental examinations under stress relaxation, fatigue and creep conditions are reported in Chapters 5 and 6. An accelerated test procedure and the formulation of crack layer instability criteria as a substitution for the conventional fracture toughness parameters are also discussed in Chapter 6.

  15. Experimental Study of Olivine-rich Troctolites

    Science.gov (United States)

    Mu, S.; Faul, U.

    2014-12-01

    This experimental study is designed to complement field observations of olivine-rich troctolites in ophiolites and from mid-ocean ridges. The olivine-rich troctolites are characterized by high volume proportion of olivine with interstitial plagioclase and clinopyroxene. Typically the clinopyroxene occurs in the form of few large, poikilitic grains. The primary purpose of this study is to investigate the effects of cooling process on the geometry of the interstitial phases (clinopyroxene and plagioclase). Experiments are conducted in a piston cylinder apparatus by first annealing olivine plus a basaltic melt with a composition designed to be in equilibrium with four phases at ~ 1 GPa and 1250ºC. Initially, we anneal the olivine-basalt aggregates at 1350 °C and 0.7 GPa for one week to produce a steady state microstructure. At this temperature only olivine and minor opx are present as crystalline phases. We then cool the samples over two weeks below their solidus temperature, following different protocols. The post-run samples are sectioned, polished, and imaged at high resolution and analyzed by using a field emission SEM. Initial observations show that under certain conditions clinopyroxene nucleates distributed throughout the aggregate at many sites, forming relatively small, rounded to near euhedral grains. Under certain conditions few cpx grains nucleate and grow with a poikilitic shape, partially or fully enclosing olivine grains, as is observed in natural samples. As for partially molten aggregates quenched form the annealing temperature, the microstructure will be characterized by tracing phase boundaries on screen by using ImageJ software. The geometry of the interstitial phases will be quantified by determining the grain boundary wetness, in this case the ratio of the length of polyphase to single phase (olivine-olivine) boundaries. Compositional data will also be used to study the change in major element compositions before and after the cooling process.

  16. Study on GSTase Activity in Benzene Induced Leukemia Patients%苯白血病患者血清GST总酶活性研究

    Institute of Scientific and Technical Information of China (English)

    李昌吉; 龙云芳; 詹承烈; 许峻峰; 王文静

    2001-01-01

    GSTs(glutathione S-transferases,GSTs/GSTase)activity was determined by KMSL method for 34 benzene induced leukemia patients,27 leukemia patients and 96 controls.GSTase activity in benzene induced leukemia patients was markedly lower than that of leukemia patients and healthy controls.The change in GSTase activity is an important factor in resulting leukemia in case of benzene exposure.By stratified analysis with GST μ gene deletion,GSTase activity in benzene induced leukemia was significantly lower than that in leukemia group and control group(P<0.01),and GSTase activity in leukemia group was lower than that of the control(P<0.05).GST μ gene deletion is an important factor affecting the GSTase activities.Since the soluble glutathione s-transferase enzymes have been grouped into five classes,it is of great importance to further determine the activity of the GST μ isoenzyme.%应用考马斯亮蓝(KMSL)法测定苯白血病患者和白血病患者血清GST总酶活性。结果表明,苯白血病患者GST总酶活性低于白血病患者和正常对照人群。分层比较发现,在GST μ基因缺失的情况下,苯白血病组与白血病组、对照组之间GST总酶活性差异有显著性(P<0.01),苯白血病患者GST总酶活性显著低于白血病患者和正常人群,而且白血病患者GST总酶活性也低于对照组(P<0.05)。在GST μ基因携带的情况下,苯白血病组与白血病组、对照组之间GST总酶活性的改变不明显。提示,由于GST总酶活性降低,从而影响了机体对苯及其衍生物的解毒作用,GST总酶活性的改变可能是苯致白血病的主要因素之一。GST μ基因缺失、GST总酶活性的降低与苯白血病的发生有一定的关系。但其相关的程度如何,需进一步测定GST μ亚型酶活性。

  17. Experimental study of finite Larmor radius effects

    International Nuclear Information System (INIS)

    Linear Z-pinches in Ar, Kr, Xe, N2, and He are experimentally studied in regimes where strong finite Larmor radius effects could provide a significant stabilizing effect. Scaling arguments show that for deuterium such a pinch has an electron line density of order 2 x 1015/cm. For higher Z plasmas a higher line density is allowed, the exact value of which depends on the average ion charge. The pinch is formed by puffing gas axially through the cathode towards the anode of an evacuated pinch chamber. When the gas reaches the anode, the pinch bank is fired. The pinch current rises in 2 to 3 μsec to a maximum of 100 to 200 kA. The pinch bank capacitance is 900 μF, and the external inductance is 100 nH. Additionally, the bank is fused to increase dI/dt. The primary diagnostics are a framing camera, a spatially resolved Mach-Zehnder interferometer, and X-ray absorption

  18. Experimental Studies of BGK Ion Waves

    Science.gov (United States)

    Skiff, F.; Noonan, W. A.; Case, A.; Bachet, G.; Doveil, F.

    2000-10-01

    Since the classic work of Bernstein, Green, and Kruskal, it has been known that plasmas support a large class of propagating disturbances that are kinetic equilibria in the propagating frame. We present experimental studies of BGK ion equilibria in singly ionized Argon plasma in two contexts. The first context is the formation of an ion phase-space hole behind a weak electrostatic shock in unmagnetized plasma. The approach toward BGK equilibrium where the contours of the ion distribution function tend to align with curves of constant particle energy in the propagating frame - is observed and the structure is shown to be a solution of the kinetic equation. The second context is a low amplitude time-periodic structure that interacts primarily with ions near wave-particle resonance in magnetized plasma. There exist theoretical predictions of nonlinear waves at very low amplitude. The existence of low amplitude nonlinear waves complicates the formulation of a complete linear description. In each context, laser induced florescence is used to measure the perturbation of the ion distribution and to determine the associated electrostatic electric field.

  19. The experimental studies of thermoacoustic cooler.

    Science.gov (United States)

    Sakamoto, Shin-ichi; Watanabe, Yoshiaki

    2004-04-01

    The experimental studies of thermoacoustic cooler consisting of acoustic loop-tube were carried out. The loop-tube was filled with the mixture of air and helium gas or air at atmospheric pressure. The dimensions of the loop-tube were 3.3 m of length, 44 mm of inner diameter and 4 mm of thickness. A pair of stacks (stack 1 and stack 2) which were sandwiched between two heat exchangers was placed symmetrically in the loop-tube. Stack 1 was employed as a prime mover and stack 2 as a heat pump. The self-sustained sound generated by the thermoacoustic effect and the cooling phenomena at the stack 2 were observed. The distribution of the sound pressures and the waveforms in the loop-tube were measured, and the frequency component of the self-sustained sound was investigated at the starting phase. The fundamental frequency component was confirmed and it was developing as the sound pressure increasing. The higher harmonics frequency components were generated and they were also developing. PMID:15047261

  20. Experimental Study of Mouse Cytomegalovirus Infected Mice

    Institute of Scientific and Technical Information of China (English)

    崔雯; 董永绥; 方峰

    2002-01-01

    Summary: In order to investigate the human cytomegalovirus (HCMV) infection, the mouse cytomegalovirus (MCMV) infected mice were experimentally studied. 6 to 8 week old female BALB/C mice with immunosuppression were selected to undergo the MCMV inoculations: intracranial inoculation and peritoneal inoculation. MCMV of the infected mice in various organs and tissues were detected by using β-gal staining and in situ nucleic acid hybridization assay. The pathological changes were observed in HE staining paraffin-embedded sections. It was found that all the MCMV infected mice showed the retardation of growth and development, and feather looseness. Both intracranial inoculation of 104 PFU viruses or peritoneal inoculation of 106 PFU viruses resulted in the pathological changes, to some extent, of various organs and tissues in the mice. The pathological changes in liver were consistent with the amount of β-gal staining positive cells, indicating the liver lesions were mainly caused by viral proliferation. It was also found that the viruses in the immunosuppressed mice subjected to intracranial inoculation could spread to whole body organs, while the viruses in the immunosuppressed mice subjected to intrapeitoneal inoculation couldn't spread to the brain, suggesting blood-brain barrier could prevent the virus from spreading to the brain.

  1. Experimental study of finite Larmor radius effects

    Energy Technology Data Exchange (ETDEWEB)

    Struve, K.W.

    1980-08-01

    Linear Z-pinches in Ar, Kr, Xe, N/sub 2/, and He are experimentally studied in regimes where strong finite Larmor radius effects could provide a significant stabilizing effect. Scaling arguments show that for deuterium such a pinch has an electron line density of order 2 x 10/sup 15//cm. For higher Z plasmas a higher line density is allowed, the exact value of which depends on the average ion charge. The pinch is formed by puffing gas axially through the cathode towards the anode of an evacuated pinch chamber. When the gas reaches the anode, the pinch bank is fired. The pinch current rises in 2 to 3 ..mu..sec to a maximum of 100 to 200 kA. The pinch bank capacitance is 900 ..mu..F, and the external inductance is 100 nH. Additionally, the bank is fused to increase dI/dt. The primary diagnostics are a framing camera, a spatially resolved Mach-Zehnder interferometer, and X-ray absorption.

  2. Nuclear magnetic resonance study on rotational dynamics of water and benzene in a series of ionic liquids: Anion and cation effects

    Science.gov (United States)

    Kimura, Hiroshi; Yasaka, Yoshiro; Nakahara, Masaru; Matubayasi, Nobuyuki

    2012-11-01

    The rotational correlation times (τ2R) for polar water (D2O) molecule and apolar benzene (C6D6) molecule were determined in ionic liquids (ILs) by means of the 2H (D) NMR spin-lattice relaxation time (T1) measurements. The solvent IL was systematically varied to elucidate the anion and cation effects separately. Five species, bis(trifluoromethylsulfonyl)imide (TFSI-), trifluoromethylsulfonate (TfO-), hexafluorophosphate (PF6-), chloride (Cl-), and formate (HCOO-), were examined for the anion effect against a fixed cation species of 1-butyl-3-methyl-imidazolium (bmim+). Four species, bmim+, N-methyl-N-butylpyrrolidinium (bmpy+), N,N,N-trimethyl-N-propylammonium (N1,1,1,3+), and P,P,P-trihexyl-P-tetradecylphosphonium (P6,6,6,14+), were employed for the cation effect against a fixed anion species of TFSI-. The τ2R ratio of water to benzene, expressed as τW/B, was used as a probe to characterize the strength of Coulombic solute-solvent interaction in ILs beyond the hydrodynamic limit based on the excluded-volume effect. The τW/B value was found to strongly depend on the anion species, and the solute dynamics are sensitive not only to the size but also to the chemical structure of the component anion. The cation effect was rather weak, in contrast. The largest and most hydrophobic P6,6,6,14+ cation was exceptional and a large τW/B was observed, indicating a unique solvation structure in [P6,6,6,14+]-based ILs.

  3. Experimental thermochemical study of 3-acetyl-2-methyl-5-phenylthiophene

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro da Silva, Manuel A.V., E-mail: risilva@fc.up.p [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Santos, Ana Filipa L.O.M. [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)

    2010-01-15

    The standard (p{sup 0}=0.1MPa) massic energy of combustion, in oxygen, of the crystalline 3-acetyl-2-methyl-5-phenylthiophene was measured, at T = 298.15 K, by rotating-bomb combustion calorimetry, from which the standard molar enthalpy of formation, in the condensed phase, was calculated as DELTA{sub f}H{sub m}{sup 0}(cr)=-(104.3+-3.1)kJ.mol{sup -1}. The corresponding standard molar enthalpy of sublimation, at T = 298.15 K, DELTA{sub cr}{sup g}H{sub m}{sup 0}=(108.9+-0.4)kJ.mol{sup -1}, was derived by the Clausius-Clapeyron equation, from the temperature dependence of the vapour pressures of this compound, measured by the Knudsen effusion mass-loss technique. From the results presented above, the standard molar enthalpy of formation, in the gaseous phase, at T = 298.15 K, was derived, DELTA{sub f}H{sub m}{sup 0}(g)=(4.6+-3.1)kJ.mol{sup -1}. This value, in conjunction with the literature values of the experimental enthalpies of formation of thiophene, 2-methylthiophene, and 3-acetylthiophene, was used to predict the enthalpic increment due to the introduction of a phenyl group in the position 2- of the thiophene ring. The calculated increment was compared with the corresponding ones in benzene and pyridine derivatives.

  4. RPBE-vdW Description of Benzene Adsorption on Au(111)

    DEFF Research Database (Denmark)

    Pedersen, Jess Wellendorff; Kelkkanen, Kari André; Mortensen, Jens Jørgen;

    2010-01-01

    der Waals interactions. The adsorption of benzene on Au(111) is an often mentioned such system where standard density functionals predict a very weak adsorption or even a repulsion, whereas a significant adsorption is observed experimentally. We show that a considerable improvement in the description...... of the adsorption of benzene on Au(111) is obtained when using the so-called RPBE-vdW functional....

  5. [bmin]Cl/[FeCl3]离子液体催化的苯与1-十八烯烷基化反应%[bmim]Cl/[FeCl3] Ionic Liquid as Catalyst for Alkylation of Benzene with 1-Octadecene

    Institute of Scientific and Technical Information of China (English)

    孙学文; 赵锁奇

    2006-01-01

    The study on the catalysis of ionic liquids for alkylation of benzene with 1-octadecene to synthesize LAB (linear alkylbenzenes) was performed. The results showed that the most important factor that governed the conversion of olefin and selectivity of LAB was reaction temperature. Moreover, the effects of different ionic liquids and molar ratio of benzene to 1-octadecene on the conversion and selectivity were obviously in different degrees. The reaction temperature, molar ratio of benzene to 1-octadecene and the amount of catalyst were lower, compared with the traditional reaction technologies. The experimental results demonstrated that the ionic liquid had higher activity at 30℃, with over 98% selectivity of monoalkylbenzene and 100% conversion of the olefm at the molar ratio 0.08 of EeCl3 in ionic liquid to 1-octadecene and 10 for benzene to 1-octadecene.

  6. Experimental and computational studies of nanofluids

    Science.gov (United States)

    Vajjha, Ravikanth S.

    The goals of this dissertation were (i) to experimentally investigate the fluid dynamic and heat transfer performance of nanofluids in a circular tube, (ii) to study the influence of temperature and particle volumetric concentration of nanofluids on thermophysical properties, heat transfer and pumping power, (iii) to measure the rheological properties of various nanofluids and (iv) to investigate using a computational fluid dynamic (CFD) technique the performance of nanofluids in the flat tube of a radiator. Nanofluids are a new class of fluids prepared by dispersing nanoparticles with average sizes of less than 100 nm in traditional heat transfer fluids such as water, oil, ethylene glycol and propylene glycol. In cold regions of the world, the choice of base fluid for heat transfer applications is an ethylene glycol or propylene glycol mixed with water in different proportions. In the present research, a 60% ethylene glycol (EG) or propylene glycol (PG) and 40% water (W) by mass fluid mixture (60:40 EG/W or 60:40 PG/W) was used as a base fluid, which provides freeze protection to a very low level of temperature. Experiments were conducted to measure the convective heat transfer coefficient and pressure loss of nanofluids flowing in a circular tube in the fully developed turbulent regime. The experimental measurements were carried out for aluminum oxide (Al2O3), copper oxide (CuO) and silicon dioxide (SiO2) nanoparticles dispersed in 60:40 EG/W base fluid. Experiments revealed that the heat transfer coefficient of nanofluids showed an increase with the particle volumetric concentration. Pressure loss was also observed to increase with the nanoparticle volumetric concentration. New correlations for the Nusselt number and the friction factor were developed. The effects of temperature and particle volumetric concentration on different thermophysical properties (e.g. viscosity, thermal conductivity, specific heat and density) and subsequently on the Prandtl number

  7. Evapotranspiration studies for protective barriers: Experimental plans

    International Nuclear Information System (INIS)

    This document describes a general theory and experimental plans for predicting evapotranspiration in support of the Protective Barrier Program. Evapotranspiration is the combined loss of water from plants and soil surfaces to the atmosphere. 45 refs., 1 fig., 4 tabs

  8. Experimental study of the pile EL3

    International Nuclear Information System (INIS)

    The results of two months' experiments, carried out at low power following the first divergence (4. July 1957) are presented. These experiments dealt with the following points: comparison of experimental and calculated values of the critical size; effects due to the introduction of absorbing materials into the principal experimental facilities, flux distribution measurements especially in these facilities, calibration of safety, control and compensating rods, determination of the average life of the neutrons. (author)

  9. Adsorption of trichloroethylene and benzene vapors onto hypercrosslinked polymeric resin

    International Nuclear Information System (INIS)

    In this research, the adsorption equilibria of trichloroethylene (TCE) and benzene vapors onto hypercrosslinked polymeric resin (NDA201) were investigated by the column adsorption method in the temperature range from 303 to 333 K and pressures up to 8 kPa for TCE, 12 kPa for benzene. The Toth and Dubinin-Astakov (D-A) equations were tested to correlate experimental isotherms, and the experimental data were found to fit well by them. The good fits and characteristic curves of D-A equation provided evidence that a pore-filling phenomenon was involved during the adsorption of TCE and benzene onto NDA-201. Moreover, thermodynamic properties such as the Henry's constant and the isosteric enthalpy of adsorption were calculated. The isosteric enthalpy curves varied with the surface loading for each adsorbate, indicating that the hypercrosslinked polymeric resin has an energetically heterogeneous surface. In addition, a simple mathematic model developed by Yoon and Nelson was applied to investigate the breakthrough behavior on a hypercrosslinked polymeric resin column at 303 K and the calculated breakthrough curves were in high agreement with corresponding experimental data.

  10. Benzene emission from the actual car fleet in relation to petrol composition in Denmark

    International Nuclear Information System (INIS)

    The present study covers an investigation of the trends in air pollution levels of benzene in Danish cities and their relationship with the benzene content in petrol. Petrol samples from the two refineries in Denmark as well as sold petrol from some representative Danish petrol stations were analysed. The benzene content in Danish petrol was reduced from 3.5% for 95 octane prior to 1995 to approx. 2% in 1995 and further to 1% in 1998. Air quality measurements of aromatic VOC are available from two Danish cities; Copenhagen since 1994 and Odense since 1997. Measurements of benzene, CO and NOx from these two locations were analysed using the Operational Street Pollution Model (OSPM) and trends in the actual emissions of these pollutants were determined. It is shown that the decrease in both the concentration levels and in the emissions was significantly larger for benzene than for CO and NOx. The decreasing trends of NOx and CO could be explained by the increasing fraction of petrol-fuelled vehicles with three way catalysts (TWC). The much steeper decreasing trend for benzene can most likely be attributed to a combination of the effect of the increasing share of the TWC vehicles and a simultaneous reduction of benzene content in Danish petrol. The reduction of benzene concentrations and emissions is observed despite that the total amount of aromatics in petrol has increased slightly in the same period. (Author)

  11. Benzene emission from the actual car fleet in relation to petrol composition in Denmark

    Science.gov (United States)

    Palmgren, Finn; Hansen, Asger B.; Berkowicz, Ruwim; Skov, Henrik

    The present study covers an investigation of the trends in air pollution levels of benzene in Danish cities and their relationship with the benzene content in petrol. Petrol samples from the two refineries in Denmark as well as sold petrol from some representative Danish petrol stations were analysed. The benzene content in Danish petrol was reduced from 3.5% for 95 octane prior to 1995 to approx. 2% in 1995 and further to 1 % in 1998. Air quality measurements of aromatic VOC are available from two Danish cities; Copenhagen since 1994 and Odense since 1997. Measurements of benzene, CO and NO x from these two locations were analysed using the Operational Street Pollution Model (OSPM) and trends in the actual emissions of these pollutants were determined. It is shown that the decrease in both the concentration levels and in the emissions was significantly larger for benzene than for CO and NO x. The decreasing trends of NO x and CO could be explained by the increasing fraction of petrol-fuelled vehicles with three way catalysts (TWC). The much steeper decreasing trend for benzene can most likely be attributed to a combination of the effect of the increasing share of the TWC vehicles and a simultaneous reduction of benzene content in Danish petrol. The reduction of benzene concentrations and emissions is observed despite that the total amount of aromatics in petrol has increased slightly in the same period.

  12. Water-clay interactions. Experimental study

    International Nuclear Information System (INIS)

    Clay minerals contribute to the chemical composition of soil and sediment groundwaters via surface and dissolution/precipitation reactions. The understanding of those processes is still today fragmentary. In this context, our experimental purpose is to identify the contribution of each reaction in the chemical composition of water in a water/clay System. Kaolinite, illite, montmorillonite are the reference clays. After a fine mineralogical study, the exchange equilibria between K+ and H+ are characterised. Different exchange sites are identified and the exchange capacities and selectivity coefficients are quantified. Then, mixtures of the three clays are equilibrated with acidic and basic (I≤10-2 M) solutions at 25 deg. C, 60 deg. C, 80 deg. C, during 320 days. The System evolution is observed by chemical analysis of the solutions and mineralogical analysis by TEM. We show that montmorillonite is unstable compared to the kaolinite/amorphous silica assemblage for solutions of pH<7. Aqueous silica is probably controlled by the kinetics of dissolution of the montmorillonite in moderate pH media. In more acidic solutions, amorphous silica precipitates. Al is under control of 'kaolinite' neo-formations. The use of the selectivity coefficients in a numerical simulation shows that K+ concentration depends on exchange reactions. The pH has a more complicated evolution, which is not completely understood. This evolution depends on both exchange equilibria and organic acid occurrence. In this type of experiments, we have demonstrated that the equilibrium equations between smectite and kaolinite are inexact. The problem of the thermodynamic nature of clays remains and is not resolved by these solubility experiments. (author)

  13. Experimental studies on mammary tumors in rats

    International Nuclear Information System (INIS)

    The purpose of this study was to assess the effects of dietary fat components in radiation-induced rat mammary carcinogenesis, and the response of chemically- or radiation-induced rat mammary tumors (MT) to experimental radiotherapy. Female rats of F344 strain were fed, for 400 days after neutron irradiation, with a synthetic diet containing various fat components with different proportion. Transplanted MTs were tested for their response to radiotherapy in terms of their hormone dependency and antigenicity. An incidence rate of MT was significantly higher in rats given 20% corn oil than in those given 5% or 1% corn oil (61.5% vs 23.0% and 23.8%). In giving diet composed of different fat components with a constant rate of 20%, fish oil significantly inhibited the incidence of MT (16.7%) as compared with lard oil (77.0%) and corn oil (61.5%). In the case of corn oil, an MT incidence rate of 61.5% was reduced to 16.7% when the total caloric intake was decreased by 70%. No association was found between the MT incidence and serum levels of estrogen or prolactin in groups of different fat components. In rats transplanted with 7, 12-dimethylbenz(a)anthracene (DMBA), some of DMBA-induced MTs were spontaneously reduced, suggesting a high antigenicity. Other DMBA-induced MTs were rejected by syngeneic recipients upon cellular transplantation. A high antigenicity may be explained by tumor take and growth with a short latency upon transplantation into immunosuppressed syngeneic recipients. Ovarian hormone-dependent MTs tended to have a higher radiosensitivity than hormone-independent autonomous MTs. DMBA-induced MTs began to reduce 10 days and were completely destroyed 30 days after irradiation, irrespective of whether they were directly exposed to or shielded from neutron. This abscopal effect can be explained by immunological reaction of the host. (Namekawa, K) 87 refs

  14. Experimental and numerical study of coaxial jets

    International Nuclear Information System (INIS)

    In some parts of Liquid Metal-cooled Reactors, notably the core exit area, hot and cold sodium jets are mixing. In the turbulent mixing region, temperature fluctuations occur and may cause surface cracking on the lower part of the above core structure. To prevent such a component from thermal striping, it is necessary to estimate the temperature fluctuations in the mixing region. Up to now, temperature fluctuations in sodium flows are generally evaluated by means of reduced scale models operating with a simulant fluid (air or water). Our objective is to give some indications on the similarity criteria when a simulant fluid is used to predict sodium temperature fluctuations in a region of mixing jets. We study a configuration of coaxial vertical jets, the inner one is cold and the outer one is hot. The experimental devices consist of two identical test sections, one operating in sodium and the other in air. We measured mean temperatures and root-mean-square of temperature fluctuations in sodium and in air. The comparison of these two sets of measurements shows that the best agreement is obtained when the air tests are performed at a sufficient level of the Reynolds number. A normalization of the power spectrum density of the temperature fluctuations is proposed to compare the frequency distribution in air and in sodium. The recent improvements in the turbulence modeling, specially the Large Eddy Simulation (LES), allows a numerical estimation of the temperature fluctuations in a region of mixing jets. Large Eddy Simulation is a powerful tool for such application where the various characteristics of the temperature fluctuations (amplitude, frequency) are needed. Thus, we computed the sodium test with the TRIO code which is developed by CEA for thermal-hydraulic applications. The LES calculation shows its ability to predict the temperature characteristics in the mixing region. (author)

  15. 室内观赏植物吸收甲醛和苯能力的比较研究%Comparative study of the absorbility of indoor decorative plants for formaldehyde and benzene

    Institute of Scientific and Technical Information of China (English)

    梁诗; 沈海燕; 陈鑫辉; 林丽琴

    2013-01-01

    This paper has chosen 60 species of indoor decorative plants to absorb formaldehyde and the other forty-one species of indoor decorative plants to absorb benzene. We have done a fumigating experiment by putting the above said plants in some self-made fumigating boxes. In so doing, we kept measuring the change of formaldehyde and benzene 24 hours later. And then we began to do our comparative study for the absorbility of the plants for formaldehyde and benzene by gradually reducing the dose of formaldehyde and benzene in the unit leaf area. The results of our experiments indicate that if the mass concentration of formaldehyde and benzene is 10 times as high as that stipulated in the national standard, all the indoor decorative plants are in a position to absorb both the formaldehyde and the benzene content in the air, though their adsorbilities vary respectively . The absorbility for formaldehyde in the unit leaf area declines as follows, for example, Aloe vera L., Philodendron selloum C.Koch, Monstera deliciosa Liebm., Chamaedorea elegans ( Mart. ) Liebm. , Syngonium podophyllum Schoot, Ficus elastica Roxb. ex Hornem. ' Decora Burgundy ' , Dracaena sanderiana Sander ex Mast. , Chlorophytum amaniense Engl. , Chlorophytum comosum ( Thunb. ) Jacq. 'Vittatum', Neoregelia carolinae (Beer) Sm. 'Tricolor Per-fecta' . However, the absorption capacity for benzene in the unit leaf area has been found declining as follows, Aloe vera L., Peperomia argyreia Merr, Schefflera arboricola (Hay.) Merr. 'Jacqueline', Guzmania lingidala (L.) mez, Philodendron selloum C.Koch, Syngonium podophyllum Schoot, Chlorophytum amaniense Engl., Yucca guatemalensis Baker Variegata' , Dieffenbachia maculata Tryun-fw' , Neoregelia carolinae (Beer) Sm. 'Tricolor Perfecta' . As a result, we have chosen six species of indoor decorative plants for our later experiments while pot and soil were made separated from the haulm. The plants have then been put into the fumigating boxes for further fumigating

  16. The ototoxic effects of ethyl benzene in rats

    NARCIS (Netherlands)

    Cappaert, N.L.M.; Klis, S.F.L.; Muijser, H.; Groot, J.C.M.J. de; Kulig, B.M.; Smoorenburg, G.F.

    1999-01-01

    Exposure to organic solvents has been shown to be ototoxic in animals and there is evidence that these solvents can induce hearing loss in humans. In this study, the effects of inhalation of the possibly ototoxic solvent ethyl benzene on the cochlear function and morphology were evaluated using thre

  17. Extraction of cadmium thiocyanate complex by tributyl phosphate in benzene

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D.; Tandon, S.N. (Roorkee Univ. (India). Dept. of Chemistry)

    1981-09-01

    The extraction of cadmium thiocyanate complex has been studied in benzene solution of tri-n-butyl phosphate. The species extracted is shown to be Cd(SCN)X.4TBP, where X is a common anion. The extraction data have also been used for achieving some metal ion separation.

  18. Selective Oxidation of Benzene to Phenol. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Sherif, F.; Kung, H.; Marshall, C.

    2000-09-30

    Direct catalytic oxidation of commodity aromatics to phenolic compounds was studied by a team from Akzo Nobel Chemicals, Argonne National Lab., and Northwestern University. Results did not exceed previously published performance. The object of the project was to selectively oxidize benzene to phenol using a conventional oxidant.

  19. Benzaldehyde in cherry flavour as a precursor of benzene formation in beverages.

    Science.gov (United States)

    Loch, Christine; Reusch, Helmut; Ruge, Ingrid; Godelmann, Rolf; Pflaum, Tabea; Kuballa, Thomas; Schumacher, Sandra; Lachenmeier, Dirk W

    2016-09-01

    During sampling and analysis of alcohol-free beverages for food control purposes, a comparably high contamination of benzene (up to 4.6μg/L) has been detected in cherry-flavoured products, even when they were not preserved using benzoic acid (which is a known precursor of benzene formation). There has been some speculation in the literature that formation may occur from benzaldehyde, which is contained in natural and artificial cherry flavours. In this study, model experiments were able to confirm that benzaldehyde does indeed degrade to benzene under heating conditions, and especially in the presence of ascorbic acid. Analysis of a large collective of authentic beverages from the market (n=170) further confirmed that benzene content is significantly correlated to the presence of benzaldehyde (r=0.61, pcherry flavoured beverages, industrial best practices should include monitoring for benzene. Formulations containing either benzoic acid or benzaldehyde in combination with ascorbic acid should be avoided. PMID:27041300

  20. Hydrogen Storage in Benzene Moiety Decorated Single-Walled Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bing-Yun; LIANG Qi-Min; SONG Chen; XIA Yue-Yuan; ZHAO Ming-wen; LIU Xiang-Dong; ZHANG Hong-Yu

    2006-01-01

    The hydrogen storage capacity of(5,5)single-walled carbon nanotubes(SWNTs)decorated chemically with benzene moieties is studied by using molecular dynamics simulations(MDSs)and density functional theory(DFT) calculations.It is found that benzene molecules colliding on (5,5) SWNTs at incident energy of 50 eV form very stable configurations of benzene moiety adsorption on the wall of SWNTs.The MDSs indicate that when the benzene moiety decorated(5,5)SWNTs and a pristine(5,5)SWNT are put in a box in which hydrogen molecules are filled to a pressure of~26 atm,the hydrogen storage capacity of the benzene moiety decorated(5,5)SWNT is about 4.7wt.% and that of the pristine (5,5) SwNT is nearly 3.9 wt.%.

  1. Effect of benzene on product evolution in a H2S/O2 flame under Claus condition

    International Nuclear Information System (INIS)

    Highlights: • Effect of trace amounts of benzene (0.3%, 0.5% and 1%) to H2S combustion process. • Benzene favored formation of H2 and reduced conversion of H2S. • Benzene reduced SO2 formation to impact sulfur production. • Benzene addition promoted CO and COS formation and degraded sulfur quality. - Abstract: Experimental results are presented on the role of benzene addition to H2S combustion at an equivalence ratio of three with respect to H2S (Claus condition) and complete combustion of benzene. The results are reported with 0.3%, 0.5% and 1% benzene addition to H2S/O2 flame. Combustion of H2S and benzene mixtures is of practical value for sulfur recovery during combustion of acid gases. The results showed that H2S combustion caused H2S to decompose to a minimum mole fraction with high conversion of H2S while the SO2 mole fraction reached a maximum value. Addition of benzene decreased the conversion of H2S with reduced mole fraction of SO2 in the reactor to subsequently reduce the formation of elemental sulfur. Benzene also caused significant production of H2, CO and COS formation along with faster decomposition of the formed SO2. Presence of benzene, even in trace amounts, in acid gas hinders sulfur conversion in a Claus reactor and increases emission of unwanted sulfur bearing compounds. Increased hydrogen production with benzene offers potential value for hydrogen recovery under certain conditions

  2. Retrievable IVC Square Stent Filter: Experimental Study

    International Nuclear Information System (INIS)

    experimental and eventual clinical studies with a commercially manufactured SSF

  3. Computatonal and experimental study of laminar flames

    Energy Technology Data Exchange (ETDEWEB)

    Smooke, M.D.; Long, M.B. [Yale Univ., New Haven, CT (United States)

    1993-12-01

    This research has centered on an investigation of the effects of complex chemistry and detailed transport on the structure and extinction of hydrocarbon flames in counterflow, cylindrical and coflowing axisymmetric configurations. The authors have pursued both computational and experimental aspects of the research in parallel. The computational work has focused on the application of accurate and efficient numerical methods for the solution of the one and two-dimensional nonlinear boundary value problems describing the various reacting systems. Detailed experimental measurements were performed on axisymmetric coflow flames using two-dimensional imaging techniques. In particular, spontaneous Raman scattering and laser induced fluorescence were used to measure the temperature, major and minor species profiles.

  4. Experimental Study of a Thermoelectric Generation System

    DEFF Research Database (Denmark)

    Zhu, Junpeng; Gao, Junling; Chen, Min;

    2011-01-01

    A flat wall-like thermoelectric generation system is developed for applications in exhaust heat of kilns. The design of the whole experimental setup is presented. The essential performance of the thermoelectric generation system is tested, including open-circuit voltage, output power, and system....... System-level simulation is carried out using a quasi-one-dimensional numerical model that enables direct comparison with experimental results. The results of both experiment and simulation will provide a foundation to improve and optimize complex thermoelectric generation systems....

  5. 46 CFR 30.25-3 - Benzene.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Benzene. 30.25-3 Section 30.25-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Commodities Regulated § 30.25-3 Benzene. The provisions contained in 46 CFR part 197, subpart C, apply to liquid cargoes containing 0.5% or more...

  6. 46 CFR 151.50-60 - Benzene.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Benzene. 151.50-60 Section 151.50-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-60 Benzene. The person in charge of...

  7. 29 CFR 1926.1128 - Benzene.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Benzene. 1926.1128 Section 1926.1128 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Toxic and Hazardous Substances § 1926.1128 Benzene....

  8. 29 CFR 1915.1028 - Benzene.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Benzene. 1915.1028 Section 1915.1028 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED... Benzene. Note: The requirements applicable to shipyard employment under this section are identical...

  9. Bio sensing Benzene in the refinery

    International Nuclear Information System (INIS)

    A biosensor based on Pseudomonas putida cells was utilized for Benzene analysis in air of an oil refinery. Biosensoristic approach was compared to gaschromatografic essay. We also developed bio sensing Benzene genetically modified Escherichia coli and tested them with refinery samples. Microbial biosensor were useful to determine air pollution.

  10. Studies of nematic to smectic-A phase transitions using synchrotron radiation. Experimental techniques and experiments

    International Nuclear Information System (INIS)

    High resolution X-ray diffraction on liquid crystals, with a triple-axis spectrometer, was initiated 4-5 years ago, using rotating-anode sources. The triple-axis spectrometer, built at Risoe, is permanently positioned at the DORIS storage ring. Triple-axis X-ray spectrometer work in general and especially at the synchrotron source is a new field and a description of the techniques used is given. The experiments described are studies of the nematic to smectic-A phase transition in liquid crystals. The first is a study of the monomolecular liquid crystal 8-barS5 (C8H17O-phi-COS-phi-C5H11, where phi denotes a benzene ring). The second experimental study is one of the reentrance phenomenon in the ternary mixture: 5CTsub(.09):7CBsub(.x):80CBsub(.91-x); where 5CT(C5H11-phi-phi-phi-CN) and 7CB(C7H15-phi-phi-CN) have only a nematic phase and not the smectic-A phase. The results are interpreted in terms of Landau theory. Finally, a frame is given for discussing the nature of the smectic-A phase and an experiment is proposed to explore the nature of the smectic-A phase together with detailed calculations of (001)- and (002)-lineshapes for the smectic-A phase. (Auth.)

  11. Velocity-dependent emission factors of benzene, toluene and C{sub 2}-benzenes of a passenger car equipped with and without a regulated 3-way catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Heeb, N.V.; Forss, A.-M.; Bach, C.; Mattrel, P. [Swiss Federal Laboratories for Materials Testing and Research, Duebendorf (Switzerland)

    2000-07-01

    Time-resolved chemical ionization mass spectrometry (Cl-MS) has been used to investigate the velocity-dependent emission factors for benzene, toluene, the C{sub 2}-benzenes (xylenes and ethyl benzene) and nitrogen monoxide of a gasoline-driven passenger car (1.4 l, model year 1995) driven with or without catalytic exhaust gas treatment. A set of seven different driving cycles - including the European Driving Cycle (EDC), the US Urban (FTP 75) and the Highway driving cycles - with a total driving time of 12,000 s have been studied. From the obtained emission data, two sets of 15,300 and 17,200 data points which represent transient driving in the velocity range of 0-150 km h{sup -1} and in an acceleration window of - 2-3 m s{sup -2} were explored to gain velocity-dependent emission factors. The passenger car, equipped with a regulated rhodium-platinum based three-way catalyst, showed optimal conversion efficiency (> 95%) for benzene in the velocity range of 60-120 km h{sup -1}. The conversion of benzene was reduced (< 80%) when driving below 50 km h{sup -1} and the BTXE emissions significantly increased when driven at higher speed and engine load (> 130 km h{sup -1}). Whereas the conversion efficiency for the class of C{sub 2}-benzenes was reduced to 10%, no net conversion could be found for toluene and benzene when driven above 130 km h{sup -1}. In contrast, the benzene and toluene emissions exceeded those of the untreated exhaust gas in the velocity range of 130-150 km h{sup -1} by 50-92% and by 10-34%, respectively. Thus, benzene and toluene were formed across the examined three-way catalyst if the engine is operated for an extended time in a fuel-rich mode (lambda < 1). (author)

  12. EXPERIMENTAL STUDIES ON FELDSPAR ORE CONCENTRATION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A series of Fe2O3-elimination experiments were conducted on feldspar samples from Tangshan Stone-powder Plant. These experimental methods include scrubbing desliming, flotation, rod milling and high gradient magnetic separation. Some technical factors of feldspar concentration and a new technological flow-sheet of ceramics raw material concentration were put forward.

  13. Blast mitigation experimental and numerical studies

    CERN Document Server

    2013-01-01

    Presents experimental methods of material and structural response to dynamic blast loads Includes computational analysis of material and structural response to dynamic blast loads Offers mitigation measures for structures in various environments Relates lab experiments to larger field tests Features more than 150 illustrations

  14. An experimental study of passive regenerator geometries

    DEFF Research Database (Denmark)

    Engelbrecht, Kurt; Nielsen, Kaspar Kirstein; Pryds, Nini

    2011-01-01

    experimental uncertainty associated with magnetocaloric material properties, all regenerators are made of aluminum. The performance of corrugated plates and dimpled plates are compared to traditional flat plate regenerators for a range of cycle times and utilizations. Each regenerator is built using 18...

  15. Use of radiation sources with mercury isotopes for real-time highly sensitive and selective benzene determination in air and natural gas by differential absorption spectrometry with the direct Zeeman effect

    International Nuclear Information System (INIS)

    A new analytical portable system is proposed for the direct determination of benzene vapor in the ambient air and natural gas, using differential absorption spectrometry with the direct Zeeman effect and innovative radiation sources: capillary mercury lamps with different isotopic compositions (196Hg, 198Hg, 202Hg, 204Hg, and natural isotopic mixture). Resonance emission of mercury at a wavelength of 254 nm is used as probing radiation. The differential cross section of benzene absorption in dependence on wavelength is determined by scanning of magnetic field. It is found that the sensitivity of benzene detection is enhanced three times using lamp with the mercury isotope 204Hg in comparison with lamp, filled with the natural isotopic mixture. It is experimentally demonstrated that, when benzene content is measured at the Occupational Exposure Limit (3.2 mg/m3 for benzene) level, the interference from SO2, NO2, O3, H2S and toluene can be neglected if concentration of these gases does not exceed corresponding Occupational Exposure Limits. To exclude the mercury effect, filters that absorb mercury and let benzene pass in the gas duct are proposed. Basing on the results of our study, a portable spectrometer is designed with a multipath cell of 960 cm total path length and detection limit 0.5 mg/m3 at 1 s averaging and 0.1 mg/m3 at 30 s averaging. The applications of the designed spectrometer to measuring the benzene concentration in the atmospheric air from a moving vehicle and in natural gas are exemplified. - Highlights: • Portable benzene analyser is designed for direct benzene detection in air and gas. • Zeeman effect absorption spectrometry ensures very low benzene detection limits. • The Hg 2537 nm emission line from capillary mercury lamp is used for absorption. • The best sensitivity and selectivity is found using Hg 204 isotope light source. • Mercury influence is eliminated by using a sorption filter at the inlet

  16. Use of radiation sources with mercury isotopes for real-time highly sensitive and selective benzene determination in air and natural gas by differential absorption spectrometry with the direct Zeeman effect

    Energy Technology Data Exchange (ETDEWEB)

    Revalde, Gita, E-mail: gitar@latnet.lv [Institute of Technical Physics, Riga Technical University, P.Valdena 3, Riga LV 1050 (Latvia); Sholupov, Sergey; Ganeev, Alexander; Pogarev, Sergey; Ryzhov, Vladimir [St. Petersburg State University, Universitetskaya nab., 7/9, St. Petersburg 199034 (Russian Federation); Skudra, Atis [Institute of Atomic Physics and Spectroscopy, University of Latvia, Skunu 4, Riga (Latvia)

    2015-08-05

    A new analytical portable system is proposed for the direct determination of benzene vapor in the ambient air and natural gas, using differential absorption spectrometry with the direct Zeeman effect and innovative radiation sources: capillary mercury lamps with different isotopic compositions ({sup 196}Hg, {sup 198}Hg, {sup 202}Hg, {sup 204}Hg, and natural isotopic mixture). Resonance emission of mercury at a wavelength of 254 nm is used as probing radiation. The differential cross section of benzene absorption in dependence on wavelength is determined by scanning of magnetic field. It is found that the sensitivity of benzene detection is enhanced three times using lamp with the mercury isotope {sup 204}Hg in comparison with lamp, filled with the natural isotopic mixture. It is experimentally demonstrated that, when benzene content is measured at the Occupational Exposure Limit (3.2 mg/m{sup 3} for benzene) level, the interference from SO{sub 2}, NO{sub 2}, O{sub 3}, H{sub 2}S and toluene can be neglected if concentration of these gases does not exceed corresponding Occupational Exposure Limits. To exclude the mercury effect, filters that absorb mercury and let benzene pass in the gas duct are proposed. Basing on the results of our study, a portable spectrometer is designed with a multipath cell of 960 cm total path length and detection limit 0.5 mg/m{sup 3} at 1 s averaging and 0.1 mg/m{sup 3} at 30 s averaging. The applications of the designed spectrometer to measuring the benzene concentration in the atmospheric air from a moving vehicle and in natural gas are exemplified. - Highlights: • Portable benzene analyser is designed for direct benzene detection in air and gas. • Zeeman effect absorption spectrometry ensures very low benzene detection limits. • The Hg 2537 nm emission line from capillary mercury lamp is used for absorption. • The best sensitivity and selectivity is found using Hg 204 isotope light source. • Mercury influence is

  17. N2- and (H2+He)-broadened cross sections of benzene (C6H6) in the 7-15 μm region for the Titan and jovian atmospheres

    Science.gov (United States)

    Sung, Keeyoon; Toon, Geoffrey C.; Crawford, Timothy J.

    2016-06-01

    In support of atmospheric remote sensing of Titan and jovian planets, we measured absorption cross sections of benzene (C6H6) in the 7-15 μm region at temperatures between 235 K and 297 K. For this, high-resolution laboratory spectra of C6H6 were obtained using two cold cells (80 cm and 2.07 cm path length) configured to a high resolution Fourier-transform infrared (FT-IR) spectrometer, Bruker IFS-125HR, at the Jet Propulsion Laboratory (JPL). The spectrum sets include 15 pure and 15 N2-broadened benzene spectra in the 630-1534 cm-1 region, along with four additional spectra broadened by an H2(85%) and He(15%) gas mixture for the 630-740 cm-1 region. From these spectra, temperature dependent benzene cross sections were obtained for gas phase benzene in the presence of N2 and (H2+He) at ambient pressures and temperatures down to 235 K. In addition, we generated two independent sets of pseudolines: one of N2-broadened benzene for Titan and the other of (H2+He)-broadened benzene for jovian planets. It is shown that the benzene pseudolines can reproduce the observed features to ˜ 5% in transmittance, including the continuum-like absorption formed by numerous overlapping weak and hot band transitions. Based on the pseudoline parameters, the integrated band intensities at 296 K for the three strongest bands in the region were measured to be 177.0(73), 14.0(10), 27.2(9)×10-17 cm-1/(molecule·cm-2) in the region of v4 at 674 cm-1, v14 at 1038.267, and v13 at 1483.985 cm-1, respectively, from the combined set of pure and N2-broadened benzene spectra. For the (H2+He) mixture-broadened benzene spectra, the integrated band intensity for v4 band in the 630-735 cm-1 region was measured to be 168.8(17)×10-17 cm-1/(molecule·cm-2) at 296 K, which is in agreement with the intensity derived from the N2-broadened benzene spectra within the combined measurement uncertainties. The results from this work show an excellent agreement (2%) with one of the latest experimental studies by

  18. Biodegradation of methane, benzene, and toluene by a consortium MBT14 enriched from a landfill cover soil.

    Science.gov (United States)

    Lee, Eun-Hee; Park, Hyunjung; Cho, Kyung-Suk

    2013-01-01

    In this study, landfill cover soil was used as an inoculum source to enrich a methane, benzene, and toluene-degrading consortium MBT14. Under a single substrate, the maximum degradation rates of methane, benzene and toluene were 1.96, 0.15, and 0.77 mmole g-DCW(-1) h(-1), respectively. Although the coexistence of benzene and toluene inhibited the methane degradation rates, the consortium was able to simultaneously degrade methane, benzene and toluene. Methane had an insignificant effect on benzene or toluene degradation. Based on 16S rDNA sequencing analysis, Cupriavidus spp. are dominant in the consortium MBT14. The combined results of this study indicate that the consortium MBT 14 is a promising bioresource for removing CH(4), benzene, and toluene from a variety of environments. PMID:23245302

  19. Experimental studies of Steel Corrugated Constructions

    Directory of Open Access Journals (Sweden)

    Lazarev Yuriy

    2016-01-01

    Full Text Available The purpose of this particular article is to assess existing calculations of steel corrugated constructions. Steel Corrugated Construction is a perspective type of constructions, which is exhibiting numerous advantages in comparison with one that currently applied in automobile and railroad networks (reinforced concrete water-throughput pipes, reinforced concrete frame bridges. The evaluation of experimental data on models of constructions of this particular type has been carried out in order to improve calculations of Steel Corrugated Constructions.

  20. Experimental study of single span railway bridges

    OpenAIRE

    Rigueiro, Constança; Rebelo, C.; Silva, L. Simões da

    2007-01-01

    The main purpose of this paper is to present some results concerning the investigation that has been done by the authors regarding the dynamic response of small to médium span railway bridges using response acceleration data colleted during the measurements carried out on single span bridges on the railway track Linz-Wels, in Austria. Using output-only methods in this experimental program, it was possible to have an estimation of the igenfrequencies, mode shapes and the corresponding viscous ...

  1. Experimental and numerical study on scratching test

    OpenAIRE

    Öpöz, Tahsin; Chen, Xun

    2013-01-01

    This paper presents recent investigation of the material removal mechanism in single grit grinding test. Single grit scratches were generated experimentally by using CBN grit on En24T steel and compared with numerical simulation by using finite element modelling (FEM). The material removal mechanism was observed along the scratch length to understand the effectiveness of ploughing and cutting mechanism throughout the scratch. Experiments showed that cutting is efficient at first half of the s...

  2. Experimental studies of Steel Corrugated Constructions

    OpenAIRE

    Lazarev Yuriy; Akhatuly Alisher; Alzhanova Raushan; Panfilova Alla

    2016-01-01

    The purpose of this particular article is to assess existing calculations of steel corrugated constructions. Steel Corrugated Construction is a perspective type of constructions, which is exhibiting numerous advantages in comparison with one that currently applied in automobile and railroad networks (reinforced concrete water-throughput pipes, reinforced concrete frame bridges). The evaluation of experimental data on models of constructions of this particular type has been carried out in orde...

  3. Experimental Studies of Overconfidence in Financial Markets

    OpenAIRE

    Michailova, Julija

    2010-01-01

    This doctoral thesis investigates the influence of overconfidence on the outcomes in experimental asset markets, both on the market and individual levels. Thesis consists of three parts. In the first part an instrument (test) is developed that is later used in economic experiments to measure subjects’ overconfidence. The second part investigates the role of market overconfidence in the occurrence of bubbles in asset prices and the emergence of other stylized facts of financial markets, namely...

  4. Testing for Team Spirit - An Experimental Study

    OpenAIRE

    Rupert Sausgruber

    2005-01-01

    It is often suggested that team spirit counteracts free-riding. Testing for team spirit with field data is difficult, however, due to an inherent identification problem. In this paper test for team spirit experimentally. In a team work task we vary subjects' information about relative team performance while we leave unchanged the structure of explicit incentives. We find that subjects contribute more to their team's project when teams observe each others' performance. We attribute this result...

  5. EXPERIMENTAL METHODS IN CONSUMER PREFERENCE STUDIES

    OpenAIRE

    Fox, John A.; Hayes, Dermot J.; Shogren, Jason F.; Kliebenstein, James B.

    1996-01-01

    Controlled experimental auctions can be used to elicit preferences for food products. We describe results from two series of experiments in which subjects revealed their willingness-to-pay for safer food. In one series, the risk reduction technology was not specified; in the other, it was identified as food irradiation. The results provide some evidence on the acceptability of food irradiation as a risk reduction technology.

  6. On the formation of new reverse micelles: a comparative study of benzene/surfactants/ionic liquids systems using UV-visible absorption spectroscopy and dynamic light scattering.

    Science.gov (United States)

    Falcone, R Darío; Correa, N Mariano; Silber, Juana J

    2009-09-15

    The microenvironment of the polar core generated in different ionic liquid reverse micelle (IL RM) systems were investigated using the solvatochromic behavior of 1-methyl-8-oxyquinolinium betaine (QB) as an absorption probe and dynamic light scattering (DLS) technique. The novel RM systems consist of two different ILs--1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (bmimTf2N)--sequestrated by two different surfactants--Triton X-100 (TX-100) and benzyl-n-hexadecyldimethylammonium chloride (BHDC)--in order to make IL/surfactant/benzene RMs. The effect of the variation of Ws (Ws=[IL]/[surfactant]) on the QB spectroscopy was used to characterize these nonaqueous RMs. DLS results confirm the formation of these IL RM systems because increasing Ws increases the droplet sizes. Moreover it is demonstrated that the structure of the sequestrated ILs depends strongly on the type of surfactant use to create the RMs. PMID:19678620

  7. Use of radiation sources with mercury isotopes for real-time highly sensitive and selective benzene determination in air and natural gas by differential absorption spectrometry with the direct Zeeman effect.

    Science.gov (United States)

    Revalde, Gita; Sholupov, Sergey; Ganeev, Alexander; Pogarev, Sergey; Ryzhov, Vladimir; Skudra, Atis

    2015-08-01

    A new analytical portable system is proposed for the direct determination of benzene vapor in the ambient air and natural gas, using differential absorption spectrometry with the direct Zeeman effect and innovative radiation sources: capillary mercury lamps with different isotopic compositions ((196)Hg, (198)Hg, (202)Hg, (204)Hg, and natural isotopic mixture). Resonance emission of mercury at a wavelength of 254 nm is used as probing radiation. The differential cross section of benzene absorption in dependence on wavelength is determined by scanning of magnetic field. It is found that the sensitivity of benzene detection is enhanced three times using lamp with the mercury isotope (204)Hg in comparison with lamp, filled with the natural isotopic mixture. It is experimentally demonstrated that, when benzene content is measured at the Occupational Exposure Limit (3.2 mg/m(3) for benzene) level, the interference from SO2, NO2, O3, H2S and toluene can be neglected if concentration of these gases does not exceed corresponding Occupational Exposure Limits. To exclude the mercury effect, filters that absorb mercury and let benzene pass in the gas duct are proposed. Basing on the results of our study, a portable spectrometer is designed with a multipath cell of 960 cm total path length and detection limit 0.5 mg/m(3) at 1 s averaging and 0.1 mg/m(3) at 30 s averaging. The applications of the designed spectrometer to measuring the benzene concentration in the atmospheric air from a moving vehicle and in natural gas are exemplified. PMID:26320799

  8. Upstream petroleum industry glycol dehydrator benzene emissions status report

    International Nuclear Information System (INIS)

    The population of dehydrators referred to are located in the Western Sedimentary Basin in northeast British Columbia, Alberta and Saskatchewan, and includes units installed at wellsites, compressor stations, gas plants, central crude oil treating facilities, and reservoir or salt cavern gas storage facilities. Benzene emissions from the still column vent on glycol dehydrators occur as a result of glycol's strong affinity for aromatic hydrocarbons, including benzene. A study was carried out to: 1) develop a list of oil and gas companies operating in Canada, 2) develop an equipment and benzene emissions inventory of glycol dehydrators, 3) develop a database in Microsoft Access format to gather and maintain inventory and emission data, 4) evaluate and validate at least 10% of the reported data, 5) develop a list of companies that manufacture dehydrators and incinerators to determine how many new dehydrators were sold for use in Canada in 1998, and 6) prepare a report summarizing findings and recommendations. The companies included in the survey were the oil and gas companies identified by the Nickels' Oil and Gas Index and others provided by CAPP, CGA, and SEPAC. The project was carried out to gather glycol dehydrator equipment and still column vent benzene emissions information. 8 refs

  9. Fluid Phase Topology of Benzene + Cyclohexane + 1-Propanol at 101.3 kPa

    Science.gov (United States)

    Andrade, R. S.; Iglesias, M.

    2015-07-01

    Isobaric vapor-liquid equilibria for the benzene + cyclohexane + 1-propanol ternary mixture were experimentally investigated at atmospheric pressure. Data were tested and considered thermodynamically consistent by means of the McDermott and Ellis method. The experimental results showed that this ternary mixture is completely miscible and exhibits three binary minimum homogeneous azeotropes and a ternary minimum azeotrope at the studied conditions. Satisfactory results were obtained for correlation of equilibrium compositions with the UNIQUAC equation and also for prediction with the UNIFAC method. In both cases, low root-mean-square deviations of the vapor mole fraction and temperature were calculated. The capability of 1-propanol as a modified distillation agent at atmospheric conditions is discussed in terms of thermodynamic topological analysis. However, because of the complex topology of the ternary mixture, it leads to a distillation scheme with two columns specifying ternary azeotrope recycling and difficult operation. Thus, this compound is not recommended as a separation agent for the binary benzene + cyclohexane azeotrope.

  10. Evaluation of Trans, Trans-Muconic Acid in Urine of Exposed Workers to Benzene in a Cokery Plant

    OpenAIRE

    M. Rahiminejad; S.Gh. Mirsattari; A. Bahrami; B. Akbari

    2006-01-01

    Introduction & Objective: Benzene is a light yellow liquid with aromatic odor and has effects to human body. The main and dangerous health effect of chronic exposure to benzene in workplace is hematopoetic system disease or blood cancer that it's primarily clinical figures are anemia, leucopenia, thrombocytopenia. The objective of this study was evaluation of benzene exposure by analysis of urinary trans, trans-muconic acid (t,t-ma) in post shift of workers.Materials & Methods: A case-contro...

  11. Experimental studies of coaxial plasma gun current

    International Nuclear Information System (INIS)

    In this investigation of a coaxial plasma gun, plasma sheath currents and related behavior are examined. Plasma behavior in the gun affects gun characteristics. Plasma gun applications are determined by the plasma behavior. The AFWL PUFF capacitor bank (72 μF, 29 nH, 120 kV) drives the plasma gun using a deuterium fill gas. The gas breakdown site is isolated from the dielectric/vacuum interface in the AFWL system. Two gas values deliver gas in the system. The first delivers gas from the gun breech and the second optional valve delivers gas to the gun muzzle. Currents and voltages are measured by Rogowski coils, B probes and capacitive voltage probes. A O-D slug model is used to predict the current, inductance, gun voltage and plasma sheath velocity. The slug model assumes the sheath transits the gun with all mass in the sheath. In the snowplow mode, the plasma sheath is thin with a sharp current rise and drop. Our system operated in a transition mode between the snowplow and deflagration modes with early snowplow behavior and late deflagration behavior. Neutrons are produced in a plasma pinch at the gun muzzle, indicating snowplow behavior. The slug theory models overall gun behavior to experimental accuracy. Experimental results are compared to four theories for plasma sheath velocities: the Alfven collisionally limited model, the Rosenbluth model, the Fishbine saturated model and a single particle drift model. Experimental velocities vary from 105 to 106 m/s. Only the single particle drift and the slug model calculations are of the right magnitude (8 x 105 m/s). The Fishbine and the Rosenbluth models predict slower velocities (2 x 105 m/s). The Alfven model is not applicable to this system

  12. Experimental study of the nucleon spin structure

    Energy Technology Data Exchange (ETDEWEB)

    Litmaath, M.F.

    1996-05-07

    After introducing the theoretical framework, which includes DIS, the Quark Parton Model (QPM) and QCD, we describe the implementation of the experiment. The SMC uses a beam of 190 GeV naturally polarized muons, scattering off nucleons in a large cryogenic target containing protons or deuterons that are polarized through Dynamic Nuclear Polarization (DNP). The target material is located in two cells in a row, with opposite polarizations. Every 5 hours the polarizations of both cells are reversed. The target polarization is measured by an NMR system. The polarization of the beam is measured in a polarimeter, located downstream of the main experimental setup. (orig.).

  13. Experimental study of the nucleon spin structure

    International Nuclear Information System (INIS)

    After introducing the theoretical framework, which includes DIS, the Quark Parton Model (QPM) and QCD, we describe the implementation of the experiment. The SMC uses a beam of 190 GeV naturally polarized muons, scattering off nucleons in a large cryogenic target containing protons or deuterons that are polarized through Dynamic Nuclear Polarization (DNP). The target material is located in two cells in a row, with opposite polarizations. Every 5 hours the polarizations of both cells are reversed. The target polarization is measured by an NMR system. The polarization of the beam is measured in a polarimeter, located downstream of the main experimental setup. (orig.)

  14. Experimental studies of Generalized Parton Distributions

    Science.gov (United States)

    Niccolai, Silvia

    2015-12-01

    Generalized Parton Distributions (GPDs) are nowadays the object of an intense effort of research, in the perspective of understanding nucleon structure. They describe the correlations between the longitudinal momentum and the transverse spatial position of the partons inside the nucleon and they can give access to the contribution of the orbital momentum of the quarks to the nucleon spin. Deeply Virtual Compton scattering (DVCS), the electroproduction on the nucleon, at the quark level, of a real photon, is the process more directly interpretable in terms of GPDs of the nucleon. Depending on the target nucleon (proton or neutron) and on the DVCS observable extracted (cross-sections, target- or beam-spin asymmetries, etc.), different sensitivity to the various GPDs for each quark flavor can be exploited. This article is focused on recent promising results, obtained at Jefferson Lab, on cross-sections and asymmetries for DVCS, and their link to GPDs. These data open the way to a “tomographic” representation of the structure of the nucleon, allowing the extraction of transverse-space densities of the quarks at fixed longitudinal momentum. The extensive experimental program to measure GPDs at Jefferson Lab with the 12 GeV-upgraded electron accelerator and the complementary detectors that will be housed in three experimental Halls (A, B and C), will also be presented.

  15. Feasibility study of the AOSTA experimental campaign

    Directory of Open Access Journals (Sweden)

    Carta M.

    2016-01-01

    Full Text Available The reduction of the nuclear waste is one of the most important nuclear issues. The high radiotoxicity of the spent fuel is due to plutonium and some minor actinides (MAs such as neptunium, americium and curium, above all. One way to reduce their hazard is to destroy by fission MAs in appropriate nuclear reactors. To allow the MAs destruction an important effort have been done on the nuclear data due to the poor knowledge in this field. In the framework of one of the NEA Expert Group on Integral Experiments for Minor Actinide Management an analysis of the feasibility of MAs irradiation campaign in the TAPIRO fast research reactor is carried out. This paper provides preliminary results obtained by calculations modelling the irradiation, in different TAPIRO irradiation channels, of some CEA samples coming from the French experimental campaign OSMOSE, loaded with different contents of MAs, in order to access, through particular peak spectrometry, to their capture cross section. On the basis of neutron transport calculation results, obtained by both deterministic and Monte Carlo methods, an estimate of the irradiated samples counting levels from the AOSTA (Activation of OSMOSE Samples in TAPIRO experimental campaign is provided.

  16. Feasibility study of the AOSTA experimental campaign

    Science.gov (United States)

    Carta, M.; Blaise, P.; Bethaz, C.; Boccia, F.; Fabrizio, V.; Geslot, B.; Grossi, A.; Gruel, A.

    2016-03-01

    The reduction of the nuclear waste is one of the most important nuclear issues. The high radiotoxicity of the spent fuel is due to plutonium and some minor actinides (MAs) such as neptunium, americium and curium, above all. One way to reduce their hazard is to destroy by fission MAs in appropriate nuclear reactors. To allow the MAs destruction an important effort have been done on the nuclear data due to the poor knowledge in this field. In the framework of one of the NEA Expert Group on Integral Experiments for Minor Actinide Management an analysis of the feasibility of MAs irradiation campaign in the TAPIRO fast research reactor is carried out. This paper provides preliminary results obtained by calculations modelling the irradiation, in different TAPIRO irradiation channels, of some CEA samples coming from the French experimental campaign OSMOSE, loaded with different contents of MAs, in order to access, through particular peak spectrometry, to their capture cross section. On the basis of neutron transport calculation results, obtained by both deterministic and Monte Carlo methods, an estimate of the irradiated samples counting levels from the AOSTA (Activation of OSMOSE Samples in TAPIRO) experimental campaign is provided.

  17. Excited state of protonated benzene and toluene

    International Nuclear Information System (INIS)

    We present photo-fragmentation electronic spectra of the simplest protonated aromatic molecules, protonated benzene and toluene, recorded under medium resolution conditions and compared with the photo-fragmentation spectrum of protonated pyridine. Despite the resolution and cold temperature achieved in the experiment, the electronic spectra of protonated benzene and toluene are structure-less, thus intrinsically broadened. This is in agreement with the large geometrical changes and the fast dynamic toward internal conversion predicted by ab initio calculations for protonated benzene [Rode et al., J. Phys. Chem. A 113, 5865–5873 (2009)

  18. Theoretical and experimental studies of elementary physics

    Energy Technology Data Exchange (ETDEWEB)

    Bodek, A.; Ferbel, T.; Melissinos, A.C.; Olsen, S.; Slattery, P.; Tipton, P.; Das, A.; Hagen, C.R.; Rajeev, S.G.; Okubo, S.

    1992-04-30

    The experimental high energy physics program is directed toward the execution of experiments that probe the basic constituents of matter and the forces between them. These experiments are carried out at national and international accelerator facilities. At the current time, we are primarily concentrating on the following projects: Direct photon production in hadronic reactions (Fermilab E706); Production of hybrid mesons in the nuclear Coulomb field; The D-Zero experiment at the Tevatron collider; Deep inelastic neutrino- and electron-nucleon scattering at FNAL and SLAC; Nonlinear QED at critical field strengths at SLAC; The Experiments at KEK (AMY, 17keV neutrino); The CDF experiment at the Tevatron collider; and SSC-related detector R D on scintillating tile- and diamond-based calorimetry and microstrip tracking detectors.

  19. Experimental Study of the Sampled Labyrinth Chaos

    Directory of Open Access Journals (Sweden)

    J. Petrzela

    2011-12-01

    Full Text Available In this paper, some new numerical as well as experimental results connected with the so-called labyrinth chaos are presented. This very unusual chaotic motion can be generated by mathematical model involving the scalar goniometrical functions which makes a three-dimensional autonomous dynamical system strongly nonlinear. Final circuitry implementation with analog core and digital parts can be used for modeling Brownian motion. From the viewpoint of generating chaotic motion by some electronic circuit, first step is to solve problems associated with the two-port nonlinear transfer functions synthesis. In the case of labyrinth chaos the finite dynamical range of the input variables introduced by the used active elements usually limits the performance greatly, similarly as it holds for the multi-grid spiral attractors. This paper shows an elegant way how to remove these obstacles by using uni-versal multiple-port with internal digital signal processing.

  20. Experimental Study of Pollutant Transfer within Dwellings

    CERN Document Server

    Koffi, Juslin; Allard, Francis; Husaunndee, Ahmad

    2010-01-01

    A mechanical ventilation principle used in French residential buildings was tested in the experimental house of the CSTB research centre. The experiments dealt with pollutant removal efficiency of this ventilation principle, mainly with air tightness and the influence of internal doors. Tracer gas constant injection method was used to simulate the pollution source in the living room. SF6 concentrations were measured in several rooms. The results showed that the air flow routes were in agreement with the theory as long as internal doors were closed. When doors were open, the air pattern was disturbed a lot; a great quantity of the emitted pollutant was measured in the bedrooms. Besides, stack effect promotes the pollutant moving towards the bedrooms under higher indoor-outdoor air temperature differences. In addition, the results showed that if the opening of the bedroom window increases the air change rate, it does not guarantee a good indoor air quality.

  1. Theoretical and experimental studies of elementary physics

    International Nuclear Information System (INIS)

    The experimental high energy physics program is directed toward the execution of experiments that probe the basic constituents of matter and the forces between them. These experiments are carried out at national and international accelerator facilities. At the current time, we are primarily concentrating on the following projects: Direct photon production in hadronic reactions; production of hybrid mesons in the nuclear Coulomb field; the D-Zero experiment at the Tevatron collider; deep inelastic neutrino- and electron-nucleon scattering at FNAL and SLAC; nonlinear QED at critical field strengths at SLAC; the experiments at KEK (AMY, 17keV neutrino); the CDF experiment at the Tevatron collider; and SSC-related detector R ampersand D on scintillating tile- and diamond-based calorimetry and microstrip tracking detectors

  2. Theoretical and experimental studies of elementary physics

    International Nuclear Information System (INIS)

    The experimental high energy physics program is directed toward the execution of experiments that probe the basic constituents of matter and the forces between them. These experiments are carried out at national and international accelerator facilities. At the current time, we are primarily concentrating on the following projects: Direct photon production in hadronic reactions (Fermilab E706); Production of hybrid mesons in the nuclear Coulomb field; The D-Zero experiment at the Tevatron collider; Deep inelastic neutrino- and electron-nucleon scattering at FNAL and SLAC; Nonlinear QED at critical field strengths at SLAC; The Experiments at KEK (AMY, 17keV neutrino); The CDF experiment at the Tevatron collider; and SSC-related detector R ampersand D on scintillating tile- and diamond-based calorimetry and microstrip tracking detectors

  3. Computational and experimental study of laminar flames

    Energy Technology Data Exchange (ETDEWEB)

    Smooke, Mitchell [Yale Univ., New Haven, CT (United States)

    2015-05-29

    During the past three years, our research has centered on an investigation of the effects of complex chemistry and detailed transport on the structure and extinction of hydrocarbon flames in coflowing axisymmetric configurations. We have pursued both computational and experimental aspects of the research in parallel on both steady-state and time-dependent systems. The computational work has focused on the application of accurate and efficient numerical methods for the solution of the steady-state and time-dependent boundary value problems describing the various reacting systems. Detailed experimental measurements were performed on axisymmetric coflow flames using two-dimensional imaging techniques. Previously, spontaneous Raman scattering, chemiluminescence, and laser-induced fluorescence were used to measure the temperature, major and minor species profiles. Particle image velocimetry (PIV) has been used to investigate velocity distributions and for calibration of time-varying flames. Laser-induced incandescence (LII) with an extinction calibration was used to determine soot volume fractions, while soot surface temperatures were measured with three-color optical pyrometry using a color digital camera. A blackbody calibration of the camera allows for determination of soot volume fraction as well, which can be compared with the LII measurements. More recently, we have concentrated on a detailed characterization of soot using a variety of techniques including time-resolved LII (TiRe-LII) for soot primary particles sizes, multi-angle light scattering (MALS) for soot radius of gyration, and spectrally-resolved line of sight attenuation (spec-LOSA). Combining the information from all of these soot measurements can be used to determine the soot optical properties, which are observed to vary significantly depending on spatial location and fuel dilution. Our goal has been to obtain a more fundamental understanding of the important fluid dynamic and chemical interactions in

  4. Electrochemical degradation of benzene in natural water using silver nanoparticle-decorated carbon nanotubes

    International Nuclear Information System (INIS)

    In this study, a novel methodology for the electrochemical degradation of benzene in natural water using silver nanoparticle-decorated carbon nanotubes has been investigated. The morphology, the structure, and the electrochemical performance of the multi-walled carbon nanotubes-silver (MWCNT-Ag) nanocomposite film were characterised by transmission electron microscopy (TEM), X-ray diffraction (XRD), and cyclic voltammetry (CV), respectively. Electrocatalytic oxidation of benzene in an aqueous solution was studied to evaluate potential applications of the MWCNT-Ag modified glassy carbon (GC) electrode in environmental science. The benzene removal efficiency in natural water containing 10 mg L−1 benzene yielded 77.9% at an applied potential of +2.0 V for 2 h using the MWCNT-Ag-GC electrode. In comparison, the removal efficiency reached only 8.0% with the bare GC electrode, showing the suitability of the MWCNT-Ag nanocomposite modified GC electrode for electro-oxidation of benzene in natural water. - Graphical abstract: Display Omitted - Highlights: • A novel methodology for the electrochemical degradation of benzene was developed. • Sensor based on silver nanoparticle-decorated carbon nanotubes was used. • The proposed method is suitable and efficient for the removal of benzene

  5. Biodegradation of high concentrations of benzene vapors in a two phase partition stirred tank bioreactor

    Directory of Open Access Journals (Sweden)

    Karimi Ali

    2013-01-01

    Full Text Available Abstract The present study examined the biodegradation rate of benzene vapors in a two phase stirred tank bioreactor by a bacterial consortium obtained from wastewater of an oil industry refinery house. Initially, the ability of the microbial consortium for degrading benzene was evaluated before running the bioreactor. The gaseous samples from inlet and outlet of bioreactor were directly injected into a gas chromatograph to determine benzene concentrations. Carbone oxide concentration at the inlet and outlet of bioreactor were also measured with a CO2 meter to determine the mineralization rate of benzene. Influence of the second non-aqueous phase (silicon oil has been emphasized, so at the first stage the removal efficiency (RE and elimination capacity (EC of benzene vapors were evaluated without any organic phase and in the second stage, 10% of silicon oil was added to bioreactor media as an organic phase. Addition of silicon oil increased the biodegradation performance up to an inlet loading of 5580 mg/m3, a condition at which, the elimination capacity and removal efficiency were 181 g/m3/h and 95% respectively. The elimination rate of benzene increased by 38% in the presence of 10% of silicone oil. The finding of this study demonstrated that two phase partition bioreactors (TPPBs are potentially effective tools for the treatment of gas streams contaminated with high concentrations of poorly water soluble organic contaminant, such as benzene.

  6. Electrochemical degradation of benzene in natural water using silver nanoparticle-decorated carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Cesarino, Ivana, E-mail: ivana@iqsc.usp.br [Instituto de Química de São Carlos, Universidade de São Paulo, C.P. 780, 13560-970, São Carlos, SP (Brazil); Cesarino, Vivian; Moraes, Fernando C.; Ferreira, Tanare C.R.; Lanza, Marcos R.V. [Instituto de Química de São Carlos, Universidade de São Paulo, C.P. 780, 13560-970, São Carlos, SP (Brazil); Mascaro, Lucia H. [Departamento de Química, Universidade Federal de São Carlos, C.P. 676, 13560-970, São Carlos, SP (Brazil); Machado, Sergio A.S. [Instituto de Química de São Carlos, Universidade de São Paulo, C.P. 780, 13560-970, São Carlos, SP (Brazil)

    2013-08-15

    In this study, a novel methodology for the electrochemical degradation of benzene in natural water using silver nanoparticle-decorated carbon nanotubes has been investigated. The morphology, the structure, and the electrochemical performance of the multi-walled carbon nanotubes-silver (MWCNT-Ag) nanocomposite film were characterised by transmission electron microscopy (TEM), X-ray diffraction (XRD), and cyclic voltammetry (CV), respectively. Electrocatalytic oxidation of benzene in an aqueous solution was studied to evaluate potential applications of the MWCNT-Ag modified glassy carbon (GC) electrode in environmental science. The benzene removal efficiency in natural water containing 10 mg L{sup −1} benzene yielded 77.9% at an applied potential of +2.0 V for 2 h using the MWCNT-Ag-GC electrode. In comparison, the removal efficiency reached only 8.0% with the bare GC electrode, showing the suitability of the MWCNT-Ag nanocomposite modified GC electrode for electro-oxidation of benzene in natural water. - Graphical abstract: Display Omitted - Highlights: • A novel methodology for the electrochemical degradation of benzene was developed. • Sensor based on silver nanoparticle-decorated carbon nanotubes was used. • The proposed method is suitable and efficient for the removal of benzene.

  7. Biodegradation of High Concentrations of Benzene Vapors in a Two Phase Partition Stirred Tank Bioreactor

    Directory of Open Access Journals (Sweden)

    Ali Karimi

    2013-01-01

    Full Text Available The present study examined the biodegradation rate of benzene vapors in a two phase stirred tank bioreactor by a bacterial consortium obtained from wastewater of an oil industry refinery house. Initially, the ability of the microbial consortium for degrading benzene was evaluated before running the bioreactor. The gaseous samples from inlet and outlet of bioreactor were directly injected into a gas chromatograph to determine benzene concentrations. Carbone oxide concentration at the inlet and outlet of bioreactor were also measured with a CO2 meter to determine the mineralization rate of benzene. Influence of the second non-aqueous phase (silicon oil has been emphasized, so at the first stage the removal efficiency (RE and elimination capacity (EC of benzene vapors were evaluated without any organic phase and in the second stage, 10% of silicon oil was added to bioreactor media as an organic phase. Addition of silicon oil increased the biodegradation performance up to an inlet loading of 5580?mg/m3, a condition at which, the elimination capacity and removal efficiency were 181?g/m3/h and 95% respectively. The elimination rate of benzene increased by 38% in the presence of 10% of silicone oil. The finding of this study demonstrated that two phase partition bioreactors (TPPBs are potentially effective tools for the treatment of gas streams contaminated with high concentrations of poorly water soluble organic contaminant, such as benzene.

  8. The effect of dose, dose rate, route of administration, and species on tissue and blood levels of benzene metabolites.

    OpenAIRE

    Henderson, R F; Sabourin, P J; Bechtold, W E; Griffith, W. C.; Medinsky, M A; Birnbaum, L S; Lucier, G W

    1989-01-01

    Studies were completed in F344/N rats and B6C3F1 mice to determine the effect of dose, dose rate, route of administration, and rodent species on formation of total and individual benzene metabolites. Oral doses of 50 mg/kg or higher saturated the capacity for benzene metabolism in both rats and mice, resulting in an increased proportion of the administered dose being exhaled as benzene. The saturating air concentration for benzene metabolism during 6-hr exposures was between 130 and 900 ppm. ...

  9. Experimental studies of lower hybrid wave propagation

    International Nuclear Information System (INIS)

    Experimental measurements of the dispersion and damping of externally excited lower hybrid waves are presented. A multiple-ring slow-wave antenna, having 2π/k/sub z/ = 23 cm, is used to excite these waves in the Princeton L3 or L4 linear devices (B = 0.5 -- 2.8 kG uniform to +- 1 percent for 1.6 m, n approximately 1010, T/sub e/ approximately 3-5 eV, T/sub i/ less than or equal to 0.1 eV, He gas, plasma diameter approximately 10 cm). The waves are localized in a spatial wave packet that propagates into the plasma along a conical trajectory which makes a small angle with respect to the confining magnetic field. Measurements of the dependence of wavelength on frequency are in good agreement with the cold plasma dispersion relation. Measured values of the wave damping are in good agreement with Landau damping by the combination of the main body of the electron distribution and a approximately 30 percent high energy (T/sub e/ approximately 15-30 eV) electron tail

  10. 46 CFR 197.565 - Notifying personnel of benzene hazards.

    Science.gov (United States)

    2010-10-01

    ... appendices A and B of this subpart or a MSDS on benzene meeting the requirements of 29 CFR 1910.1200(g) is... 46 Shipping 7 2010-10-01 2010-10-01 false Notifying personnel of benzene hazards. 197.565 Section... AND HEALTH STANDARDS GENERAL PROVISIONS Benzene § 197.565 Notifying personnel of benzene hazards....

  11. Modulation of phase-II enzyme activities in benzene treated ovariectomized rats.

    Science.gov (United States)

    Verma, Yeshvandra; Rana, S V S

    2011-05-01

    The aim of the study was to determine the influence of ovariectomy on phase II enzymes viz. glutathione-S-transferase (GST), glutathione peroxidase (GPX) and catalase (CAT) in liver and kidney of female rats treated with benzene. The results showed the significant decrease of the GST and GPX activity in benzene treated rats after ovariectomy. However progesterone supplementation stimulated the activity of GST and GPX in liver and kidney of benzene treated non ovariectomized and ovariectomized rats. Progesterone supplementation to benzene treated ovariectomized rats helps to gain in CAT activity. Our results on DNA damage using single cell gel electrophoresis also confirmed our findings on antioxidant enzymes. The results showed that lack of protective progesterone against benzene toxicity is reflected in alterations in antioxidant enzyme activities. However progesterone therapy to benzene treated ovariectomized rats results in activating the antioxidant defence system. Since female workers are engaged in industrial sector, these results are important from occupational health point of view. Benzene exposure affects their reproductive health. Nevertheless, it could be modulated by suitable hormonal therapy. PMID:21787707

  12. Benzene derivatives adsorbed to the Ag(111) surface: Binding sites and electronic structure

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Daniel P.; Tymińska, Nina; Zurek, Eva, E-mail: ezurek@buffalo.edu [Department of Chemistry, State University of New York at Buffalo, Buffalo, New York 14260-3000 (United States); Simpson, Scott [Department of Chemistry, State University of New York at Buffalo, Buffalo, New York 14260-3000 (United States); School of Science, Penn State Erie, The Behrend College, 4205 College Drive, Erie, Pennsylvania 16563 (United States)

    2015-03-14

    Dispersion corrected Density Functional Theory calculations were employed to study the adsorption of benzenes derivatized with functional groups encompassing a large region of the activated/deactivated spectrum to the Ag(111) surface. Benzenes substituted with weak activating or deactivating groups, such as methyl and fluoro, do not have a strong preference for adsorbing to a particular site on the substrate, with the corrugations in the potential energy surface being similar to those of benzene. Strong activating (N(CH{sub 3}){sub 2}) and deactivating (NO{sub 2}) groups, on the other hand, possess a distinct site preference. The nitrogen in the former prefers to lie above a silver atom (top site), but in the latter a hollow hexagonal-closed-packed (H{sub hcp}) site of the Ag(111) surface is favored instead. Benzenes derivatized with classic activating groups donate electron density from their highest occupied molecular orbital to the surface, and those functionalized with deactivating groups withdraw electron density from the surface into orbitals that are unoccupied in the gas phase. For benzenes functionalized with two substituents, the groups that are strongly activating or deactivating control the site preference and the other groups assume sites that are, to a large degree, dictated by their positions on the benzene ring. The relative stabilities of the ortho, meta, and para positional isomers of disubstituted benzenes can, in some cases, be modified by adsorption to the surface.

  13. Benzene derivatives adsorbed to the Ag(111) surface: Binding sites and electronic structure

    International Nuclear Information System (INIS)

    Dispersion corrected Density Functional Theory calculations were employed to study the adsorption of benzenes derivatized with functional groups encompassing a large region of the activated/deactivated spectrum to the Ag(111) surface. Benzenes substituted with weak activating or deactivating groups, such as methyl and fluoro, do not have a strong preference for adsorbing to a particular site on the substrate, with the corrugations in the potential energy surface being similar to those of benzene. Strong activating (N(CH3)2) and deactivating (NO2) groups, on the other hand, possess a distinct site preference. The nitrogen in the former prefers to lie above a silver atom (top site), but in the latter a hollow hexagonal-closed-packed (Hhcp) site of the Ag(111) surface is favored instead. Benzenes derivatized with classic activating groups donate electron density from their highest occupied molecular orbital to the surface, and those functionalized with deactivating groups withdraw electron density from the surface into orbitals that are unoccupied in the gas phase. For benzenes functionalized with two substituents, the groups that are strongly activating or deactivating control the site preference and the other groups assume sites that are, to a large degree, dictated by their positions on the benzene ring. The relative stabilities of the ortho, meta, and para positional isomers of disubstituted benzenes can, in some cases, be modified by adsorption to the surface

  14. The role of C-H$\\ldots$ interaction in the stabilization of benzene and adamantane clusters

    Indian Academy of Sciences (India)

    R Mahesh Kumar; M Elango; R Parthasarathi; Dolly Vijay; V Subramanian

    2012-01-01

    In this investigation, a systematic attempt has been made to understand the interaction between adamantane and benzene using both ab initio and density functional theory methods. C-H$\\ldots$ type of interaction between C-H groups of adamantane and cloud of benzene is found as the important attraction for complex formation. The study also reveals that the methylene (-CH2) and methine (-CH) groups of adamantane interact with benzene resulting in different geometrical structures. And it is found that the former complex is stronger than the later. The diamondoid structure of adamantane enables it to interact with a maximum of four benzene molecules, each one along the four faces. The stability of the complex increases with increase in the number of benzene molecules. The energy decomposition analysis of adamantane-benzene complexes using DMA approach shows that the origin of the stability primarily arises from the dispersive interaction. The theory of atoms in molecules (AIM) supports the existence of weak interaction between the two systems. The electrostatic topography features provide clues for the mode of interaction of adamantane with benzene.

  15. Survey of Recycled Nano Magnetic Particle in Benzene Removal from Aqueous Solution

    OpenAIRE

    Amin M.M.; Bina B.; Samani Majd A.M.; Pourzamani H.

    2013-01-01

    The removal of benzene, a hazardous monoaromatic compound, from aqueous solution by recycled nano magnetic particle (NM) Fe3O4 in batch condition was evaluated. Regeneration studies verified that the benzene adsorbed by the NM could be easily desorbed by temperature. So that the benzene removal effi-ciency was 98.7% for raw NM, 97.8% for first recycled NM and 97.4 percent for second recycled NM. It is expected that the Fe3O4 nanoparticles with fine grain size (20-30 nm) will be used as one of...

  16. Spin Polarization Inversion at Benzene-Absorbed Fe4N Surface

    KAUST Repository

    Zhang, Qian

    2015-05-27

    We report a first-principle study on electronic structure and simulation of the spin-polarized scanning tunneling microscopy graphic of a benzene/Fe4N interface. Fe4N is a compound ferromagnet suitable for many spintronic applications. We found that, depending on the particular termination schemes and interface configurations, the spin polarization on the benzene surface shows a rich variety of properties ranging from cosine-type oscillation to polarization inversion. Spin-polarization inversion above benzene is resulting from the hybridizations between C pz and the out-of-plane d orbitals of Fe atom.

  17. Experimental study of oxidative DNA damage

    DEFF Research Database (Denmark)

    Loft, S; Deng, Xiaohong; Tuo, J;

    1998-01-01

    compounds have been studied in animal experiments mainly in rats and mice, and generally with measurement of 8-oxodG with HPLC-EC. A large number of well-known carcinogens induce 8-oxodG formation in liver and/or kidneys. Moreover several animal studies have shown a close relationship between induction of...

  18. Density functional theory study of the interaction of vinyl radical, ethyne, and ethene with benzene, aimed to define an affordable computational level to investigate stability trends in large van der Waals complexes

    Energy Technology Data Exchange (ETDEWEB)

    Maranzana, Andrea, E-mail: andrea.maranzana@unito.it, E-mail: anna.giordana@hotmail.com, E-mail: vincenzo.barone@sns.it, E-mail: mauro.causa@unina.it, E-mail: mipavone@unina.it; Giordana, Anna, E-mail: andrea.maranzana@unito.it, E-mail: anna.giordana@hotmail.com, E-mail: vincenzo.barone@sns.it, E-mail: mauro.causa@unina.it, E-mail: mipavone@unina.it; Indarto, Antonius, E-mail: antonius.indarto@che.itb.ac.id; Tonachini, Glauco, E-mail: glauco.tonachini@unito.it [Dipartimento di Chimica, Università di Torino, Corso Massimo D’Azeglio 48, I-10125 Torino (Italy); Barone, Vincenzo, E-mail: andrea.maranzana@unito.it, E-mail: anna.giordana@hotmail.com, E-mail: vincenzo.barone@sns.it, E-mail: mauro.causa@unina.it, E-mail: mipavone@unina.it [Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126, Pisa (Italy); Causà, Mauro, E-mail: andrea.maranzana@unito.it, E-mail: anna.giordana@hotmail.com, E-mail: vincenzo.barone@sns.it, E-mail: mauro.causa@unina.it, E-mail: mipavone@unina.it [Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università di Napoli “Federico II,” Via Cintia, 80126 Napoli (Italy); Pavone, Michele, E-mail: andrea.maranzana@unito.it, E-mail: anna.giordana@hotmail.com, E-mail: vincenzo.barone@sns.it, E-mail: mauro.causa@unina.it, E-mail: mipavone@unina.it [Dipartimento di Scienze Chimiche, Università di Napoli “Federico II,” Complesso Universitario di Monte Sant’Angelo, Via Cintia, I-80126 Napoli (Italy)

    2013-12-28

    Our purpose is to identify a computational level sufficiently dependable and affordable to assess trends in the interaction of a variety of radical or closed shell unsaturated hydro-carbons A adsorbed on soot platelet models B. These systems, of environmental interest, would unavoidably have rather large sizes, thus prompting to explore in this paper the performances of relatively low-level computational methods and compare them with higher-level reference results. To this end, the interaction of three complexes between non-polar species, vinyl radical, ethyne, or ethene (A) with benzene (B) is studied, since these species, involved themselves in growth processes of polycyclic aromatic hydrocarbons (PAHs) and soot particles, are small enough to allow high-level reference calculations of the interaction energy ΔE{sub AB}. Counterpoise-corrected interaction energies ΔE{sub AB} are used at all stages. (1) Density Functional Theory (DFT) unconstrained optimizations of the A−B complexes are carried out, using the B3LYP-D, ωB97X-D, and M06-2X functionals, with six basis sets: 6-31G(d), 6-311 (2d,p), and 6-311++G(3df,3pd); aug-cc-pVDZ and aug-cc-pVTZ; N07T. (2) Then, unconstrained optimizations by Møller-Plesset second order Perturbation Theory (MP2), with each basis set, allow subsequent single point Coupled Cluster Singles Doubles and perturbative estimate of the Triples energy computations with the same basis sets [CCSD(T)//MP2]. (3) Based on an additivity assumption of (i) the estimated MP2 energy at the complete basis set limit [E{sub MP2/CBS}] and (ii) the higher-order correlation energy effects in passing from MP2 to CCSD(T) at the aug-cc-pVTZ basis set, ΔE{sub CC-MP}, a CCSD(T)/CBS estimate is obtained and taken as a computational energy reference. At DFT, variations in ΔE{sub AB} with basis set are not large for the title molecules, and the three functionals perform rather satisfactorily even with rather small basis sets [6-31G(d) and N07T], exhibiting

  19. Density functional theory study of the interaction of vinyl radical, ethyne, and ethene with benzene, aimed to define an affordable computational level to investigate stability trends in large van der Waals complexes.

    Science.gov (United States)

    Maranzana, Andrea; Giordana, Anna; Indarto, Antonius; Tonachini, Glauco; Barone, Vincenzo; Causà, Mauro; Pavone, Michele

    2013-12-28

    Our purpose is to identify a computational level sufficiently dependable and affordable to assess trends in the interaction of a variety of radical or closed shell unsaturated hydro-carbons A adsorbed on soot platelet models B. These systems, of environmental interest, would unavoidably have rather large sizes, thus prompting to explore in this paper the performances of relatively low-level computational methods and compare them with higher-level reference results. To this end, the interaction of three complexes between non-polar species, vinyl radical, ethyne, or ethene (A) with benzene (B) is studied, since these species, involved themselves in growth processes of polycyclic aromatic hydrocarbons (PAHs) and soot particles, are small enough to allow high-level reference calculations of the interaction energy ΔEAB. Counterpoise-corrected interaction energies ΔEAB are used at all stages. (1) Density Functional Theory (DFT) unconstrained optimizations of the A-B complexes are carried out, using the B3LYP-D, ωB97X-D, and M06-2X functionals, with six basis sets: 6-31G(d), 6-311 (2d,p), and 6-311++G(3df,3pd); aug-cc-pVDZ and aug-cc-pVTZ; N07T. (2) Then, unconstrained optimizations by Møller-Plesset second order Perturbation Theory (MP2), with each basis set, allow subsequent single point Coupled Cluster Singles Doubles and perturbative estimate of the Triples energy computations with the same basis sets [CCSD(T)//MP2]. (3) Based on an additivity assumption of (i) the estimated MP2 energy at the complete basis set limit [EMP2/CBS] and (ii) the higher-order correlation energy effects in passing from MP2 to CCSD(T) at the aug-cc-pVTZ basis set, ΔECC-MP, a CCSD(T)/CBS estimate is obtained and taken as a computational energy reference. At DFT, variations in ΔEAB with basis set are not large for the title molecules, and the three functionals perform rather satisfactorily even with rather small basis sets [6-31G(d) and N07T], exhibiting deviation from the computational

  20. Recommended sublimation pressure and enthalpy of benzene

    International Nuclear Information System (INIS)

    Highlights: • Sublimation pressures of benzene were measured. • Benzene thermodynamic properties in the state of ideal gas were calculated. • Recommended sublimation pressure and enthalpy of benzene were developed. -- Abstract: Recommended vapor pressures of solid benzene (CAS Registry Number: 71-43-2) which are consistent with thermodynamically related crystalline and ideal-gas heat capacities as well as with properties of the liquid phase at the triple point temperature (vapor pressure, enthalpy of vaporization) were established. The recommended data were developed by a multi-property simultaneous correlation of vapor pressures and related thermal data. Vapor pressures measured in this work using the static method in the temperature range from 233 K to 260 K, covering pressure range from 99 Pa to 1230 Pa, were included in the simultaneous correlation. The enthalpy of sublimation was established with uncertainty significantly lower than the previously recommended values

  1. Studies of experimental bladder tumors, 3

    International Nuclear Information System (INIS)

    Enzymatologic, histochemical and histologic investigations were performed on the effects of SLA, a β-glucoronidase inhibitor, and Linaic irradiation in an experimental BBN bladder tumor of rats. Bladder tumors were macroscopically thumb-head size in the cases with no treatment of with SLA application, but were shrunk by roentgen irradiation. The number of the rats with reduced tumor was respectively 3 in the group with roentgen irradiation. S-LDH activity of the cancer-carrying animals was markedly elevated as compared with that of the normal rat. SLA application caused no change in S-LDH activity of cancer-carrying animals, but roentgen irradiation resulted in a marked decrease in S-LDH activity of the similar animals with bladder tumors. The level of this decrease was dependent on the dosage of one time irradiation; no change was observed by 200, 300 and 500 rad, little decrease was seen by 750 rad, and marked decrease was observed after 1,000 and 1,500 rad radiation. Histological observation of the effects of irradiation could be summarized as follows. Histological changes were seen in the cases of macroscopic shrinkage by 3,000 rad irradiation. In this group, an individual variation was noticed not only macroscopically but microscopically. One time irradiation of 200, 300 and 500 rad resulted in no histological change, but that of 750, 1,000, and 1,500 rad caused a slight, but not marked, histological change. Tissue distribution of β-glucuronidase was examined by means of Naphthol-AS-BI-glucuronide method in the group without any treatment and the group with SLA administration. β-glucuronidase activity was noticed in the epithelial cells and interstitial stroma of the tumor tissue, but the effect of SLA on β-glucuronidase activity was not observed histochemically. (author)

  2. Low-pressure phase diagram of crystalline benzene from quantum Monte Carlo

    CERN Document Server

    Azadi, Sam

    2016-01-01

    We study the low-pressure (0 to 10 GPa) phase diagram of crystalline benzene using quantum Monte Carlo (QMC) and density functional theory (DFT) methods. We consider the $Pbca$, $P4_32_12$, and $P2_1/c$ structures as the best candidates for phase I and phase II. We perform diffusion quantum Monte Carlo (DMC) calculations to obtain accurate static phase diagrams as benchmarks for modern van der Waals density functionals. We use density functional perturbation theory to compute phonon contribution in the free-energy calculations. Our DFT enthalpy-pressure phase diagram indicates that the $Pbca$ and $P2_1/c$ structures are the most stable phases within the studied pressure range. The DMC Gibbs free-energy calculations predict that the room temperature $Pbca$ to $P2_1/c$ phase transition occurs at 2.1(1) GPa. This prediction is consistent with available experimental results at room temperature. Our DMC calculations show an estimate of 50.6$\\pm$0.5 kJ/mol for crystalline benzene lattice energy.

  3. Biodegradation kinetics of benzene, toluene and xylene compounds: microbial growth and evaluation of models.

    Science.gov (United States)

    Feisther, Vódice Amoroz; Ulson de Souza, Antônio Augusto; Trigueros, Daniela Estelita Goes; de Mello, Josiane Maria Muneronde; de Oliveira, Déborade; Guelli Ulson de Souza, Selene M A

    2015-07-01

    The biodegradation kinetics of BTX compounds (benzene, toluene, and xylene) individually and as mixtures was studied using models with different levels of sophistication. To compare the performance of the unstructured models applied in this work we used experimental data obtained here and some results published in the literature. The system description was based on the material balances of key components for batch operations, where the Monod and Andrews models were applied to predict the biodegradation of individual substrates. To simulate the biodegradation kinetics of substrate mixtures, models of substrate inhibition were applied along with the Sum Kinetics with Interaction Parameters (SKIP) models, where for two-component association toluene-xylene SKIP model presented better performance and for tri-component association benzene-toluene-xylene, the uncompetitive inhibition model was better. The kinetic parameters were estimated via a global search method known as Particle Swarm Optimization (PSO). The main result of this study is that the sophisticated biodegradation kinetics of BTX mixtures can be successfully described by applying the SKIP model, with the main advantage being the consideration of the substrate interactions. PMID:25627469

  4. Theoretical & Experimental Studies of Elementary Particles

    Energy Technology Data Exchange (ETDEWEB)

    McFarland, Kevin

    2012-10-04

    Abstract High energy physics has been one of the signature research programs at the University of Rochester for over 60 years. The group has made leading contributions to experimental discoveries at accelerators and in cosmic rays and has played major roles in developing the theoretical framework that gives us our ``standard model'' of fundamental interactions today. This award from the Department of Energy funded a major portion of that research for more than 20 years. During this time, highlights of the supported work included the discovery of the top quark at the Fermilab Tevatron, the completion of a broad program of physics measurements that verified the electroweak unified theory, the measurement of three generations of neutrino flavor oscillations, and the first observation of a ``Higgs like'' boson at the Large Hadron Collider. The work has resulted in more than 2000 publications over the period of the grant. The principal investigators supported on this grant have been recognized as leaders in the field of elementary particle physics by their peers through numerous awards and leadership positions. Most notable among them is the APS W.K.H. Panofsky Prize awarded to Arie Bodek in 2004, the J.J. Sakurai Prizes awarded to Susumu Okubo and C. Richard Hagen in 2005 and 2010, respectively, the Wigner medal awarded to Susumu Okubo in 2006, and five principal investigators (Das, Demina, McFarland, Orr, Tipton) who received Department of Energy Outstanding Junior Investigator awards during the period of this grant. The University of Rochester Department of Physics and Astronomy, which houses the research group, provides primary salary support for the faculty and has waived most tuition costs for graduate students during the period of this grant. The group also benefits significantly from technical support and infrastructure available at the University which supports the work. The research work of the group has provided educational opportunities

  5. Experimental studies of actinides in molten salts

    Energy Technology Data Exchange (ETDEWEB)

    Reavis, J.G.

    1985-06-01

    This review stresses techniques used in studies of molten salts containing multigram amounts of actinides exhibiting intense alpha activity but little or no penetrating gamma radiation. The preponderance of studies have used halides because oxygen-containing actinide compounds (other than oxides) are generally unstable at high temperatures. Topics discussed here include special enclosures, materials problems, preparation and purification of actinide elements and compounds, and measurements of various properties of the molten volts. Property measurements discussed are phase relationships, vapor pressure, density, viscosity, absorption spectra, electromotive force, and conductance. 188 refs., 17 figs., 6 tabs.

  6. Experimental studies of actinides in molten salts

    International Nuclear Information System (INIS)

    This review stresses techniques used in studies of molten salts containing multigram amounts of actinides exhibiting intense alpha activity but little or no penetrating gamma radiation. The preponderance of studies have used halides because oxygen-containing actinide compounds (other than oxides) are generally unstable at high temperatures. Topics discussed here include special enclosures, materials problems, preparation and purification of actinide elements and compounds, and measurements of various properties of the molten volts. Property measurements discussed are phase relationships, vapor pressure, density, viscosity, absorption spectra, electromotive force, and conductance. 188 refs., 17 figs., 6 tabs

  7. Experimental Studies on Glass Fiber Concrete

    Directory of Open Access Journals (Sweden)

    J.D.Chaitanya kumar

    2016-06-01

    Full Text Available Concrete is one of the most widely recognized development material for the most part delivered by utilizing locally accessible ingredients. The development of concrete has brought about the essential need for additives both chemical and mineral to improve the performance of concrete. Hence varieties of admixtures such as fly ash, coconut fibre have been used so far. Hence an attempt has been made in the present investigation to study the behaviour of glass fibre in concrete. The present trend in concrete technology is towards increasing the strength and durability of concrete to meet the demands of the modern construction. The main aim of the study is to study the effect of glass fibre in the concrete. Glass fibre has the high tensile strength and fire resistant properties thus reducing the loss of damage during fire accidents. The addition of these fibres into concrete can dramatically increase the compressive strength, tensile strength and split tensile strength of the concrete. In this study, tests have done for the concrete with glass fibre of 0.5%, 1%, 2% and 3% of cement by adding as an admixture

  8. Trust in triads: an experimental study

    OpenAIRE

    V.W. Buskens; Raub, W.; Veer, J. van der

    2010-01-01

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

  9. Hepatic encephalopathy: clinical and experimental studies

    OpenAIRE

    Rijt, Carin

    1991-01-01

    textabstractThe pathogenesis of hepatic encephalopathy is still unsolved. Therapy, therefore, is often insufficient. For the development of effective, new therapies insight into the disease-inducing substrates and the mechanisms of its toxic actions in the central nervous system ·are required. For both studies on pathogenesis and therapy of hepatic encephalopathy, methods for the quantitation of its severity are needed. For the measurement of hepatic encephalopathy clinical grading, conventio...

  10. Experimental study on a simplified crossflow turbine

    Directory of Open Access Journals (Sweden)

    Chiyembekezo S. Kaunda, Cuthbert Z. Kimambo, Torbjorn K. Nielsen

    2014-01-01

    Full Text Available The main aim of the study is to enhance the design of a Crossflow turbine, as an appropriate technology for small-scale power generation. This study evaluates the performance of a simplified Crossflow turbine at conditions other than the ‘best efficiency point’. It also explores the ‘reaction’ behavior of the Crossflow turbine as well as characterizes the torque transfer in the two stages of the turbine. The experiments were conducted on a physical simplified Crossflow turbine model using the test facilities in the Waterpower Laboratory at the Norwegian University of Science and Technology. The results show that the maximum turbine efficiency is 79%, achieved at a head of 5m and reduced speed of 13.4; making it a low speed turbine. This turbine efficiency compares well with some reported efficiency values. The result also show that the turbine is efficient when it operates with a degree of reaction and this is achieved at large valve openings; validating observations that the Crossflow turbine is not a pure impulse turbine. Performance evaluation outside the best efficiency point shows that the efficiency decreases with increase in head above the best efficiency head. The turbine efficiency is not sensitive to flow variations: except at a head of 3m, at all tested heads, 25% of the flow at best efficiency point still generates efficiency of above 50%. Torque characterization shows that the second stage plays a significant role in torque transfer, especially when at large valve openings. Therefore, design efforts must also look at how the flow inside the runner interior space can be controlled so that the jet enters the second stage with optimum flow angles. The use of strain gauge to characterize the torque produced using momentum principle as employed in this study presents an additional opportunity to analyze the trends in the torque transfer.

  11. Experimental and modelling studies of infiltration

    International Nuclear Information System (INIS)

    This presentation describes a study of infiltration in the unsaturated soil with the objective of estimating the recharge to a phreatic aquifer. The study area is at the border of the city of Milan (Northern Italy), which draws water for both domestic and industrial purposes from ground water resources located beneath the urban area. The rate of water pumping from the aquifer system has been varying during the XX century, depending upon the number of inhabitants and the development of industrial activities. This caused variations with time of the depth of the water table below the ground surface and in turn some emergencies: the two most prominent episodes correspond to the middle '70s, when the water table in the city centre was about 30 m below the undisturbed natural conditions, and to the last decade, when the water table has raised at a rate of approximately 1 m/year and caused infiltrations in deep constructions (garages and building foundations, the underground railways, etc.). We have developed four ground water flow models at different scales, which share some characteristics: they are based on quasi-3D approximation (horizontal flow in the aquifers and vertical flow in the aquitards), conservative finite-differences schemes for regular grid with square cells in the horizontal plane and are implemented with proprietary computer codes. Among the problems that were studied for the development of these models, I recall some numerical problems, related to the behaviour of the phreatic aquifer under conditions of strong exploitation. Model calibration and validation for ModMil has been performed with a two-stage process, i.e., using some of the available data for model calibration and the remaining data for model validation. The application of geophysical exploration techniques, in particular seismic and geo-electrical prospecting, has been very useful to complete the data and information on the hydro-geological structure obtained from stratigraphic logs

  12. An experimental study of rip channel flow

    DEFF Research Database (Denmark)

    Drønen, Nils Kjetil; Karunarathna, H.; Fredsøe, Jørgen;

    2002-01-01

    of the three-dimensional structure of the flow in the area where the rip channel, the bar and the trough meet and well inside the rip channel are presented. These measurements reveal that 3D effects play an important role, and that a depth-integrated viewpoint may not always be sufficient for......A laboratory study of the flow over a bar with a single rip channel has been performed. First, the well-known pattern of a bar circulation cell with a strong offshore-directed current out through the rip channel and a weaker onshore-directed return flow over the bar is documented. Then measurements...

  13. Experimental study of isovector spin sum rules

    Energy Technology Data Exchange (ETDEWEB)

    Alexandre Deur; Peter Bosted; Volker Burkert; Donald Crabb; Kahanawita Dharmawardane; Gail Dodge; Tony Forest; Keith Griffioen; Sebastian Kuhn; Ralph Minehart; Yelena Prok

    2008-02-04

    We present the Bjorken integral extracted from Jefferson Lab experiment EG1b for $0.05<2.92$ GeV$^2$. The integral is fit to extract the twist-4 element $f_{2}^{p-n}$ which is large and negative. Systematic studies of this higher twist analysis establish its legitimacy at $Q^{2}$ around 1 GeV$^{2}$. We also extracted the isovector part of the generalized forward spin polarizability $\\gamma_{0}$. Although this quantity provides a robust test of Chiral Perturbation Theory, our data disagree with the calculations.

  14. Experimental Study of Fractal Image Compression Algorithm

    Directory of Open Access Journals (Sweden)

    Chetan R. Dudhagara

    2012-08-01

    Full Text Available Image compression applications have been increasing in recent years. Fractal compression is a lossy compression method for digital images, based on fractals. The method is best suited for textures and natural images, relying on the fact that parts of an image often resemble other parts of the same image. In this paper, a study on fractal-based image compression and fixed-size partitioning will be made, analyzed for performance and compared with a standard frequency domain based image compression standard, JPEG. Sample images will be used to perform compression and decompression. Performance metrics such as compression ratio, compression time and decompression time will be measured in JPEG cases. Also the phenomenon of resolution/scale independence will be studied and described with examples. Fractal algorithms convert these parts into mathematical data called "fractal codes" which are used to recreate the encoded image. Fractal encoding is a mathematical process used to encode bitmaps containing a real-world image as a set of mathematical data that describes the fractal properties of the image. Fractal encoding relies on the fact that all natural, and most artificial, objects contain redundant information in the form of similar, repeating patterns called fractals.

  15. Peroxidase-dependent metabolism of benzene's phenolic metabolites and its potential role in benzene toxicity and carcinogenicity.

    OpenAIRE

    Smith, M T; Yager, J W; Steinmetz, K L; Eastmond, D A

    1989-01-01

    The metabolism of two of benzene's phenolic metabolites, phenol and hydroquinone, by peroxidase enzymes has been studied in detail. Studies employing horseradish peroxidase and human myeloperoxidase have shown that in the presence of hydrogen peroxide phenol is converted to 4,4'-diphenoquinone and other covalent binding metabolites, whereas hydroquinone is converted solely to 1,4-benzoquinone. Surprisingly, phenol stimulates the latter conversion rather than inhibiting it, an effect that may ...

  16. Experimental Studies of Dynamics at Solid Surfaces

    Science.gov (United States)

    Germer, Thomas Avery

    1992-01-01

    Measurements of thermal and photoinduced processes on metal surfaces point to the importance of transient intermediate species in the understanding of dynamics. Experiments were performed using photoinduced desorption (PID), thermal desorption spectroscopy (TDS), high-resolution and time -resolved electron-energy-loss spectroscopy (HREELS and TREELS), and femtosecond multiphoton photoemission spectroscopy. The thermal and photoinduced reactions of Mo(CO)_6 adsorbed on Rh(100) were studied to better understand energy transfer between a photoexcited molecule and a metal surface. The Mo(CO)_6 partially dissociated upon adsorption, allowing a comparison to be made between Mo(CO)_6 adsorbed on the fragment-covered surface and a more ordered CO-covered surface. The energy transfer rate was found to be larger on the fragment-covered surface. The thermal reaction of hydrogen gas with oxygen adsorbed on Pt(111) was studied with TREELS between 130 and 160 K, observing the modes associated with hydroxyl adsorbed on the surface as a function of time while the sample, preadsorbed with atomic oxygen, was exposed to hydrogen gas. In coordination between Monte Carlo calculations and kinetic simulations, a model was developed whereby the reaction to form hydroxyl occurred between a molecular hydrogen precursor and oxygen at island boundaries. The photoinduced reaction of adsorbed atomic hydrogen and molecular oxygen to form hydroxyl and water on Pt(111) was studied in order to understand the reactivity of the hot oxygen atoms produced by photodissociation of molecular oxygen. The final products of the two oxygen -hydrogen reactions were the same. A measurement was made of the cross section for NO photodesorption from Pt(111) at 90 K. All of these experiments pointed to a need to make transient measurements on the ultrashort time scale in order to develop a more microscopic understanding of the dynamical processes that are occurring. As a result, a novel time-of-flight analyzer was

  17. Patterns of power communication: an experimental study

    Directory of Open Access Journals (Sweden)

    Kali Prasad

    1958-07-01

    Full Text Available "Communication in one form or others is the basis of all social interaction. This paper deals with a particular aspect of communication namely, the effect of power and authority on the communication patterns that are set up between individuals. In such situation usually a power differential exists between the individuals as in the case of an employer and an employee, and this is responsible for setting up different attitudes in the mind of the people. The aim of the experiment described here is to study the reactions in individuals to expression of praise and hostility. The main finding is that those who are in power e.g. the employers are not so susceptible to praise as those who are subordinate to them. Also, a superior power person is less disturbed by hostile act of a subordinate than vice versa.

  18. Experimental study of diffuse auroral precipitations

    International Nuclear Information System (INIS)

    First chapter is devoted to low energy electron precipitation in the evening sector of the auroral magnetosphere, during quiet and disturbed magnetic periods. Four subjects are studied in detail: the latitude distribution of the varied auroral forms and their relations to external magnetosphere; the time coefficients related to precipitations, the form and the dynamic of the diffuse precipitation equatorial frontier; the precipitation effect on the ionosphere concentration. The last part of the chapter shows that the plasma convection in the magnetosphere, associated to wave-particle interactions near the equatorial accounts for the principal characteristics of the evening sector diffuse electronic precipitations. The second chapter deals with subauroral precipitations of low energy ions, after the magnetospheric substorms, in the high latitude regions of the morning sector

  19. Experimental Studies of Top Quark Production

    CERN Document Server

    Wagner-Kuhr, Jeannine

    2016-01-01

    In this review article three promising aspects of top quark production are discussed: the charge asymmetry in top quark pair production, the search for resonant top quark pair production, and electroweak single top quark production. First, an overview of the theoretical predictions of top quark pair and single top quark production is given. Then, for each topic the general analysis strategy and improvements are exemplarily explained using selected analyses and are put into the context of the global status at the beginning of LHC Run II and progress in this field. The example analyses discussed in more detail in this article use data from the LHC experiment CMS and for the charge asymmetry studies also data from the Tevatron experiment CDF have been used.

  20. Experimental study on phase perception in speech

    Institute of Scientific and Technical Information of China (English)

    BU Fanliang; CHEN Yanpu

    2003-01-01

    As the human ear is dull to the phase in speech, little attention has been paid tophase information in speech coding. In fact, the speech perceptual quality may be degeneratedif the phase distortion is very large. The perceptual effect of the STFT (Short time Fouriertransform) phase spectrum is studied by auditory subjective hearing tests. Three main con-clusions are (1) If the phase information is neglected completely, the subjective quality of thereconstructed speech may be very poor; (2) Whether the neglected phase is in low frequencyband or high frequency band, the difference from the original speech can be perceived by ear;(3) It is very difficult for the human ear to perceive the difference of speech quality betweenoriginal speech and reconstructed speech while the phase quantization step size is shorter thanπ/7.

  1. Experimental techniques for cement hydration studies

    Directory of Open Access Journals (Sweden)

    Andreas Luttge

    2011-10-01

    Full Text Available Cement hydration kinetics is a complex problem of dissolution, nucleation and growth that is still not well understood, particularly in a quantitative way. While cement systems are unique in certain aspects they are also comparable to natural mineral systems. Therefore, geochemistry and particularly the study of mineral dissolution and growth may be able to provide insight and methods that can be utilized in cement hydration research. Here, we review mainly what is not known or what is currently used and applied in a problematic way. Examples are the typical Avrami approach, the application of Transition State Theory (TST to overall reaction kinetics and the problem of reactive surface area. Finally, we suggest an integrated approach that combines vertical scanning interferometry (VSI with other sophisticated analytical techniques such as atomic force microscopy (AFM and theoretical model calculations based on a stochastic treatment.

  2. Experimental study on the adiabatic shear bands

    International Nuclear Information System (INIS)

    Four martensitic steels (Z50CDV5 steel, 28CND8 steel, 35NCDV16 steel and 4340 steel) with different hardness between 190 and 600 Hsub(B) (Brinell hardness), have been studied by means of dynamic compressive tests on split Hopkinson pressure bar. Microscopic observations show that the fracture are associated to the development of adiabatic shear bands (except 4340 steel with 190 Hsub(B) hardness). By means of tests for which the deformation is stopped at predetermined levels, the measurement of shear and hardness inside the band and the matrix indicates the chronology of this phenomenon: first the localization of shear, followed by the formation of adiabatic shear band and ultimatly crack initiation and propagation. These results correlated with few simulations by finite elements have permitted to suggest two mecanisms of deformation leading to the formation of adiabatic shear bands in this specific test

  3. Experimental study of relative, turbulent diffusion

    DEFF Research Database (Denmark)

    Mann, J.; Ott, Søren; Andersen, J.S.

    1999-01-01

    The purpose is to study relative turbulent diffusion under controlled, reproducible conditions in the laboratory in order to estimate the constant C in Richardson-Obukhov's law. We get C #approx# 0.4 -- 0.6. We furthermore measure the distance-neighbourfunction, which is the probability density...... function of the separation of two fluid particles that are initially close to each other. We find that the model proposed by Richardson is far superior to the one suggested by Batchelor. To obtain these resultswe use the Particle Tracking (PT) technique to measure trajectories of fluid particles in a water...... tank with two oscillating grids generating turbulence. In the experiments reported here we have obtained Reynolds numbers based on Taylor's microscale ofabout one hundred. The PT system, which is also described in this report, consists of four CCD cameras, a synchronous light source and a recording...

  4. Thinned fibre Bragg grating as a fuel adulteration sensor: simulation and experimental study

    Science.gov (United States)

    Agarwal, S.; Prajapati, Y. K.; Mishra, V.

    2015-12-01

    This paper presents the implementation of a thinned fibre Bragg grating as a fuel adulteration sensor for volatile organic compounds. The proposed sensor can detect upto 10% adulteration of benzene, toluene and xylene: hydrocarbons precisely, whereas traditional methods can detect only upto 20% adulteration. The results obtained from the experiments are verified using Finite Difference Time Domain method. It is found that experimental results have very less deviation from simulation results. The proposed sensor provides us with the new possibility that may have commercial application, as well.

  5. Experimental and clinical studies with intraoperative radiotherapy

    International Nuclear Information System (INIS)

    Studies of normal tissue tolerance to intraoperative radiotherapy were done upon 65 dogs subjected to laparotomy and 11 million electron volt electron irradiation in doses ranging from zero to 5,000 rads. Results of studies indicated that intact aorta and vena cava tolerate up to 5,000 rads without loss of structural integrity. Ureteral fibrosis and stenosis develop at doses of 3,000 rads or more. Arterial anastomoses heal after doses of 4,500 rads, but fibrosis can lead to occlusion. Intestinal suture lines heal after doses of 4,500 rads. Bile duct fibrosis and stenosis develop at doses of 2,000 rads or more. Biliary-enteric anastomoses fail to heal at any dose level. A clinical trial of intraoperative radiotherapy combined with radical surgery was performed upon 20 patients with advanced malignant tumors which were considered unlikely to be cured by conventional therapies and which included carcinomas of the stomach, carcinomas of the pancreas, carcinomas involving the hilus of the liver, retroperitoneal sarcomas and osteosarcomas of the pelvis. All patients underwent resection of gross tumor, followed by intraoperative irradiation of the tumor bed and regional nodal basins. Some patients received additional postoperative external beam radiotherapy. Treatment mortality for combined operation and radiotherapy occurred in four of 20 patients. Postoperative complications occurred in four of the 16 surviving patients. Local tumor control was achieved in 11 of the 16 surviving patients, with an over-all median follow-up period of 18 months. The clinical trial suggested that intraoperative radiotherapy is a feasible adjunct to resection in locally advanced tumors, that the resulting mortality and morbidity is similar to that expected from operation alone and that local tumor control may be improved

  6. Adsorption from n-heptane/benzene liquid mixture on acid leached bentonite powders

    International Nuclear Information System (INIS)

    In this study, adsorption excess isotherms of n-heptane/benzene liquid mixture on hydrochloric acid leached bentonite powders were determined. Adsorptions were conducted at 25 °C for 48 h. Experimental results were evaluated with both Schay–Nagy (SN) and Everett (E) methods. Specific surface areas (SSN and SE) of the powders were calculated regarding monolayer adsorption capacity of the preferentially adsorbed benzene. Adsorption equilibrium constants (K ≫ 1) were obtained by the E-method. The SE and SSN values are closed to each other. SE-values were found much lower than the corresponding Brunauer, Emmett and Teller (BET)-values. This difference was discussed with respect to the interaction of adsorbed molecules with solid surface, their collision diameter, molar cross sectional surface area and orientation in dense monolayer. Even the maximum for the SE was not associated with the maxima for K and nanopore volume (V), their values changed approximately parallel to each other with respect to the HCl% by the leaching.

  7. The benzene radical anion: A computationally demanding prototype for aromatic anions

    International Nuclear Information System (INIS)

    The benzene radical anion is studied with ab initio coupled-cluster theory in large basis sets. Unlike the usual assumption, we find that, at the level of theory investigated, the minimum energy geometry is non-planar with tetrahedral distortion at two opposite carbon atoms. The anion is well known for its instability to auto-ionization which poses computational challenges to determine its properties. Despite the importance of the benzene radical anion, the considerable attention it has received in the literature so far has failed to address the details of its structure and shape-resonance character at a high level of theory. Here, we examine the dynamic Jahn-Teller effect and its impact on the anion potential energy surface. We find that a minimum energy geometry of C2 symmetry is located below one D2h stationary point on a C2h pseudo-rotation surface. The applicability of standard wave function methods to an unbound anion is assessed with the stabilization method. The isotropic hyperfine splitting constants (Aiso) are computed and compared to data obtained from experimental electron spin resonance experiments. Satisfactory agreement with experiment is obtained with coupled-cluster theory and large basis sets such as cc-pCVQZ

  8. Very low-energy electron scattering from benzene: experiment and theory

    International Nuclear Information System (INIS)

    Low-energy collision studies have shown that the scattering cross section for electrons by benzene rises sharply at electron impact energies below ∼200 meV. This was attributed in earlier work to electron attachment and formation of benzene anions with lifetimes τ≥1 μs. A detailed study of electron attachment to benzene is reported here that makes use of Rydberg atom techniques. The data provide no evidence for the formation of long-lived benzene anions, although a small collisional ionization signal is observed which is consistent with the formation of short-lived excited anions (τ≤3 ps). An alternative explanation for the rapid rise in cross section at low energy is presented, based on ab initio scattering calculations. These calculations indicate that virtual state scattering takes place at low energies. Possible implications of this are briefly discussed. (author)

  9. Radiolysis of Aqueous Benzene Solutions

    International Nuclear Information System (INIS)

    Aerated and deaerated aqueous solutions of benzene have been irradiated with 60Co γ-rays. The products of radiolysis in deaerated, unbuffered or acid, solutions were phenol, biphenyl, hydrogen and in acid solutions also hydrogen peroxide with the following yields: G(phenol) = 0. 37 (0. 37), G(biphenyl) = 1.3 (1.7), G(H2) = 0.44 (0. 43) and G(H2O2) = 0 (0.60), the figures in brackets giving the results for acid solutions. The results are shown to agree with the conclusion that k(e-aq + H2O2) >> k(H + H2O2). Furthermore, the results indicate that a competition takes place between the reactions: 2 C6H6OH · -> dimer -> biphenyl. C6H7 · + C6H6OH · -> dimer -> biphenyl. The yields in aerated, unbuffered or acid, solutions were: G(phenol) = 2.1 (2.3), G(biphenyl) = 0 (0), and G(H2O2) = 2.2 (3.1), the figures in brackets being valid for acid solutions. The ratio k(H + C6H6)/k(H + O2) was 1.4x10-2. The results indicate that peroxides, or more probably hydroperoxides, take part in the reactions. After the addition of Fe2+ or Fe3+ to aerated acid solutions G(phenol) was increased to 6.6 and 3.4 respectively. Oxygen was consumed more rapidly in the presence of Fe. Reaction mechanisms are discussed

  10. Experimental study of high beta toroidal plasmas

    International Nuclear Information System (INIS)

    Experiments on the Wisconsin Levitated Toroidal Octupole have produced a wide range of stable high β plasmas with β significantly above single fluid MHD theory predictions. A stable β approx. 8% plasma, twice the fluid limit, is obtained with 5 rho/sub i/ approx. L/sub n/ and tau/sub β/ approx. = 6000 tau/sub Alfven/ = 600 μsec. The enhanced stability is explained with a kinetic treatment that includes the effect of finite ion gyroradius which couples the ballooning mode to an ion drift wave. In a more collisional, large gyroradius (2 rho/sub i/ approx. L/sub n/) regime, a stable β approx. 35% plasma is obtained with a decay time of 1000 Alfven times. Measurement of the equilibrium magnetic field in this regime indicates that the diamagnetic current density is five times smaller than predicted by ideal MHD, probably due to ion gyroviscosity. Particle transport is anomalous and ranges from agreement with the classical diffusion rate at the highest beta, lowest field plasma (B/sub P/ = 200 G), to thirteen times the classical rate in a β=11%, high field plasma (B/sub P/ = 860 G) where the level of enhancement increase with magnetic field. Fluctuations in density, electrostatic potential, and magnetic field have been studied in plasmas with β from 0.1% to 40%

  11. Experimental Study on Hydrocarbon Fuel Thermal Stability

    Institute of Scientific and Technical Information of China (English)

    J.S.Chin; A.H.Lefebvre

    1992-01-01

    The-thermal stability characteristics of kerosine-type fuels are examined using a heated-tube apparatus which allows independent control of fuel pressure,fuel temperature,tube-wall temperature and fuel flow rate.This method is identified simply as a "constant wall temperature method”,It is different from a previous widely used method ,which is identified as a “Constant heat flux method”,It is a single-pass system.Rate of deposition on the tube walls are measured by weighing the test tube before and after each test.For a fuel temperature of 250℃,it is found that deposition rates increease continuously with increase in tubewall temperature.This finding contradicts the results of previous studies which had led to the conclusion that deposition rates increase with increase in wall temperature up to a certain value(around 650K) beyond which any further increase in wall temperature causes the rate of deposition to decline.The present results show clearly that the constant wall temperature method is more suitable for assessing the thermal stability of gas turbine fuels.

  12. Experimental Studies of Electrothermal Plasma Gun

    International Nuclear Information System (INIS)

    The aim of the present work is to study the capillary plasma discharge dynamics and characteristics. The capillary plasma device is a new technology for producing high density plasma after ablating the capillary wall using a pulsed electric power. An Electrothermal Plasma Gun (ETG) is composed of a capillary discharge tube made of Teflon operated with simple RLC circuit. The device called Electrothermal Gun (ETG) which is composed of 4 capacitors (70 μF, 10 kV, 1.28 μH) connected in parallel to a plasma source by means of one high power supply. The gun was operated in open air at discharge energies between 35 J - 3.5 kJ according to charging voltage. The work presented in this thesis covers the following items, 1- Measurements of the basic parameters and characterizations of the pretest results of the electrical circuits and capillary plasma discharge using Rogowski coil, voltage probe and Photomultiplier. 2- Material processing including (physics of the surface modifications, the morphology of the surface by using Scanning Electron Microscope (SEM) at different conditions, compositions of the materials by using X-ray Fluorescence (XRF), Micro hardness test and material particle deposition.

  13. Experimental thermochemical study of two chlorodinitroaniline isomers

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro da Silva, Manuel A.V., E-mail: risilva@fc.up.p [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687 P-4169-007 (Portugal); Ribeiro da Silva, Maria D.M.C.; Santos, Ana Filipa L.O.M.; Ferreira, Ana I.M.C. Lobo; Galvao, Tiago L.P. [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687 P-4169-007 (Portugal)

    2010-04-15

    The standard (p{sup 0}=0.1MPa) molar enthalpies of formation of 2-chloro-4,6-dinitroaniline and 4-chloro-2,6-dinitroaniline, in the gaseous phase, at T = 298.15 K, were derived from the combination of the values of the standard molar enthalpies of formation, in the crystalline phase, and of the standard molar enthalpies of sublimation, at the same temperature. The standard molar enthalpies of formation, in the crystalline phase, were derived from the standard massic energies of combustion, in oxygen, measured by rotating-bomb combustion calorimetry. The standard molar enthalpies of sublimation were calculated, by the application of the Clausius-Clapeyron equation, to the vapour pressures at several temperatures, measured by Knudsen effusion technique. The values of the standard molar enthalpies of formation of 2-chloro-4,6-dinitroaniline and 4-chloro-2,6-dinitroaniline, in the gaseous phase, at T = 298.15 K, are discussed in terms of enthalpic increments, and the enthalpy of isomerization between the two compounds is compared with the same parameter for two isomers of chloronitroaniline, studied in previous works.

  14. An experimental study of radiation pneumonitis

    International Nuclear Information System (INIS)

    The study was undertaken to evaluate the radiological and microscopic findings of radiation penumonitis. All 50 rats, which were used for the experiment, received a single dose of 2,000 rads of radiation on right lung using 60Co teletherapy. Chest teleroentgenograms were checked weekly for 13 weeks and microscopic examinations of irradiated lung were performed monthly after irradiation. The results obtained are summarized as follows. 1. In roentgenologic examination, radiation pneumonitis began to appear 4 weeks after irradiation and progressed with time intervals and began to resolve after 11 weeks. 2. Chest roentgenologic findings were pneumonic consolidation, atelectasis, and pleural effusion of irradiated right lung with compensatory hyper-inflation of left lung. 3. In the microscopic examination, pneumonitis appeared 2 weeks after irradiation and progressed with time intervals and began to resolve after 8 weeks. 4. The microscopic findings were fibrin deposit in alveoli and increased cellularity, vascular thickening, edema and congestion. After septal fibrosis and hyperplasia of bronchial mucosa, suggesting early regenerative change of radiation fibrosis, were noted 12 weeks after irradiation

  15. Experimental and clinical studies on CT lymphography

    International Nuclear Information System (INIS)

    Indirect lymphography using computed tomographic apparatus (CT Lymphography) was attempted in 15 dogs with newly devised contrast medium for the opacification of hilar and mediastinal lymphnodes. Clinical application was performed in 2 cases of lung cancer. Newly devised contrast material is an emulsion, which consists of oily contrast medium, non-ionic surfactant and glucose solution. The contrast medium was injected percutaneously into subdiaphragmatic space, or into bronchial walls by bronchofiberscopic technique. CT was able to demonstrate the opacified hilar and mediastinal nodes much more in number than demonstrated in conventional radiograms. It was true in 6 to 11 cases when injected into subdiaphragmatic spaces, and in 2 of 4 cases with an injection into bronchial walls. In clinical studies, CT revealed opacification of mediastinal nodes in one case of lung cancer. Although the procedure is still inferior to the demonstrability of routine indirect lymphography for the evaluation of the fine structure of each node, it showed no remarkable side effects. As the satisfactory method of opacifying hilar and mediastinal nodes has not yet been established, our method is thought to be of value in applying for detection of the metastatic lymphnodes. (author)

  16. Hydrogeologic characterization and assessment of bioremediation of chlorinated benzenes and benzene in wetland areas, Standard Chlorine of Delaware, Inc. Superfund Site, New Castle County, Delaware, 2009-12

    Science.gov (United States)

    Lorah, Michelle M.; Walker, Charles W.; Baker, Anna C.; Teunis, Jessica A.; Majcher, Emily H.; Brayton, Michael J.; Raffensperger, Jeff P.; Cozzarelli, Isabelle M.

    2014-01-01

    Wetlands at the Standard Chlorine of Delaware, Inc. Superfund Site (SCD) in New Castle County, Delaware, are affected by contamination with chlorobenzenes and benzene from past waste storage and disposal, spills, leaks, and contaminated groundwater discharge. In cooperation with the U.S. Environmental Protection Agency, the U.S. Geological Survey began an investigation in June 2009 to characterize the hydrogeology and geochemistry in the wetlands and assess the feasibility of monitored natural attenuation and enhanced bioremediation as remedial strategies. Groundwater flow in the wetland study area is predominantly vertically upward in the wetland sediments and the underlying aquifer, and groundwater discharge accounts for a minimum of 47 percent of the total discharge for the subwatershed of tidal Red Lion Creek. Thus, groundwater transport of contaminants to surface water could be significant. The major contaminants detected in groundwater in the wetland study area included benzene, monochlorobenzene, and tri- and di-chlorobenzenes. Shallow wetland groundwater in the northwest part of the wetland study area was characterized by high concentrations of total chlorinated benzenes and benzene (maximum about 75,000 micrograms per liter [μg/L]), low pH, and high chloride. In the northeast part of the wetland study area, wetland groundwater had low to moderate concentrations of total chlorinated benzenes and benzene (generally not greater than 10,000 μg/L), moderate pH, and high sulfate concentrations. Concentrations in the groundwater in excess of 1 percent of the solubility of the individual chlorinated benzenes indicate that a contaminant source is present in the wetland sediments as dense nonaqueous phase liquids (DNAPLs). Consistently higher contaminant concentrations in the shallow wetland groundwater than deeper in the wetland sediments or the aquifer also indicate a continued source in the wetland sediments, which could include dissolution of DNAPLs and

  17. Markets and morals: an experimental survey study.

    Directory of Open Access Journals (Sweden)

    Julio J Elias

    Full Text Available Most societies prohibit some market transactions based on moral concerns, even when the exchanges would benefit the parties involved and would not create negative externalities. A prominent example is given by payments for human organs for transplantation, banned virtually everywhere despite long waiting lists and many deaths of patients who cannot find a donor. Recent research, however, has shown that individuals significantly increase their stated support for a regulated market for human organs when provided with information about the organ shortage and the potential beneficial effects a price mechanism. In this study we focused on payments for human organs and on another "repugnant" transaction, indoor prostitution, to address two questions: (A Does providing general information on the welfare properties of prices and markets modify attitudes toward repugnant trades? (B Does additional knowledge on the benefits of a price mechanism in a specific context affect attitudes toward price-based transactions in another context? By answering these questions, we can assess whether eliciting a market-oriented approach may lead to a relaxation of moral opposition to markets, and whether there is a cross-effect of information, in particular for morally controversial activities that, although different, share a reference to the "commercialization" of the human body. Relying on an online survey experiment with 5,324 U.S. residents, we found no effect of general information about market efficiency, consistent with morally controversial markets being accepted only when they are seen as a solution to a specific problem. We also found some cross-effects of information about a transaction on the acceptance of the other; however, the responses were mediated by the gender and (to a lesser extent religiosity of the respondent--in particular, women exposed to information about legalizing prostitution reduced their stated support for regulated organ payments. We

  18. Uremic pruritus. Clinical and experimental studies.

    Science.gov (United States)

    Ståhle-Bäckdahl, M

    1989-01-01

    The aim of the study was to investigate clinical aspects of pruritus in maintenance hemodialysis patients and to evaluate factors of putative pathogenic importance. 60-65% of the patients in a maintenance hemodialysis program during a two-year period suffered from itching. Patients with pruritus tended to have been on dialysis treatment longer than those without pruritus (p = 0.05), otherwise there was no difference in clinical data or routine laboratory tests. Measurement of itch intensity continuously over one week in 28 patients using a computerized method showed that itching peaked at night after two days without dialysis, was relatively high during treatment and lowest during the day following dialysis. Our results suggest that the accumulation of pruritogens between dialysis sessions influences the intensity of itching. Most patients had "dry" skin. Recording of the stratum corneum water content by measurement of electrical capacitance, in 31 patients (19 with pruritus) and 12 controls, disclosed no significant difference between dialysis patients and controls, but a tendency that pruritic patients had a lower water content than the other subjects. In different body areas, there was a positive correlation in all groups between the clinical estimation of xerosis and hydration. Serum concentrations of parathyroid hormone (PTH) were significantly higher in dialysis patients with pruritus than in those without, but there was no correlation between the degree of symptoms and the PTH level. Indirect immunohistochemistry revealed no immunoreactivity for different parts of the PTH molecule in skin biopsies from uremic patients. Intradermal injections of PTH fragments did not evoke itching or other cutaneous reactions in patients or controls. Our results do not support PTH as a peripheral mediator of uremic itching. Flare reactions induced by intradermal histamine injections were significantly smaller in 26 dialysis patients (18 with pruritus) than in 9 healthy

  19. An experimental study on pump clogging

    International Nuclear Information System (INIS)

    For sewage pump that various foreign substance is flowed into, anti-clogging performance is a factor as important as pump efficiency in order to avoid clogging trouble by foreign substance. Many investigations about pump inner flow and pump efficiency estimation have been carried out conventionally in order to realize coexistence with anti-clogging performance and pump performance. And these results have been reflected in construction of the running water section design method. As a index of anti-clogging performance, ''impeller passage diameter'' which is diameter of spherical solid that can pass through the pump is used widely. And there are various type of the sewage pump which have large impeller passage diameter. However real cause of clog is not a solid, and it is fibrous material such as towel and clothes, vinyl and paper diaper. In most case these material accumulate in the pump, so that clog is occurred. In this study, for the purpose of quantification of anti-clogging performance against fibrous materials, the factor that affect to clogging of pump was investigated by pump model test using a string. The test is done based on Taguchi method. In this test, type of the pump model, diameter of the string, material of the string, length of the string and flow rate are selected for the factor, and the effect that they have on the clogging of the pump was investigated. As a result of this test, it was made clear that length of the string has a strong influence on the clogging of the pump. And from the result of this test, evaluation method of anti-clogging performance of the pump against fibrous material by using string was considered. According to the result of above test based on Taguchi method, it was assumed that quantification of anti-clogging performance against fibrous materials is possible by flowing plural strings into the pump and calculating the probability of passing. Plurality sewage pumps of different types were evaluated based

  20. Genotoxic and histotoxic effects of air pollutants at a benzene station on albino rats

    OpenAIRE

    Mohamed Abousalem; Amer Elgerwi; Abdel Baset El-Mashad

    2014-01-01

    Background: This study was designed to explore the hazardous effects of occupational exposure to air pollutants arising from benzene stations. Methods: A total of 48 albino rats were divided into three groups each of sixteen animals. Groups-I and II were kept at a benzene station for 60 and 120 days, respectively; while group-III was kept as a control under normal laboratory conditions. At the end of the experiment, animals were sacrificed and bone marrow samples were taken to investigate ...

  1. Application of nuclear reaction analysis to the study of hydrogen and benzene adsorption on monocrystals of nickel and of the alloy Pt{sub 50}Ni{sub 50}; Application de l`analyse par reactions nucleaires a l`etude de l`adsorption de l`hydrogene et du benzene sur des monocristaux de nickel et d`alliage Pt{sub 50}Ni{sub 50}

    Energy Technology Data Exchange (ETDEWEB)

    Benmansour, M.

    1992-02-01

    Contribution of nuclear reaction analysis to studies of gas adsorption on surfaces comes from their ability to measure adsorbate concentrations lower than one monolayer with high accuracy. Study of hydrogen analysis by {sup 1}H({sup 15}N, {alpha}{gamma}){sup 12}C reaction has allowed to define the analytical characteristics of these methods. Deuterium analysis by {sup 2}D({sup 15}N, p{gamma}{sup 16}N and {sup 2}D({sup 15}N, n{gamma}){sup 16}O reactions has allowed a study of coadsorption of benzene and H using D-labelled molecules, the carbon concentration being determined from the {sup 12}C(d, p{sub 0}){sup 13}C and {sup 13}C(p, {gamma}){sup 14}N reactions. The nuclear reaction on H has been firstly applied to the measurement of room temperature H coverage of Ni (111). The maximum surface coverage of 0.6 ({+-} 0.05) monolayer is in good agreement with previously published values. Then, H adsorption on (111) and (110) faces of Pt{sub 50} Ni{sub 50} alloy has been studied at 115 to 400 K and 10{sup -8} to 10{sup -4} mbar. H coverage at saturation, obtained for low temperature adsorption, is 0.92 ({+-} 0.1) monolayer on (110) face and 0.18 ({+-} 0.04) monolayer on (111) face. These values are notably lower than saturation coverages of Ni and Pt single crystals. For (110) surface, H adsorption energy has been deduced from adsorption isobares and its variation with coverage determined. An interpretation of the results, taking into account the different segregation profiles of the metallic atoms for these two faces, is proposed. In a benzene - H coadsorption study on Ni (111), the measurement of H, D, and C concentrations on the surface was used to show the room temperature predominant surface reaction.

  2. MODELING AND SIMULATION OF A BENZENE RECOVERY PROCESS BY EXTRACTIVE DISTILLATION

    Directory of Open Access Journals (Sweden)

    L. B. Brondani

    2015-03-01

    Full Text Available Abstract Extractive distillation processes with N-formylmorpholine (NFM are used industrially to separate benzene from six carbon non-aromatics. In the process studied in this work, the stream of interest consists of nearly 20 different hydrocarbons. A new set of NRTL parameters was correlated based on literature experimental data. Both vapor-liquid equilibrium as well as infinite dilution activity coefficient data were taken into account; missing parameters were estimated with the UNIFAC group contribution model. The extractive distillation process was simulated using ASPEN Plus®. Very good agreement with plant data was obtained. The influences of the main operational parameters, solvent to feed ratio and solvent temperature, were studied. Theoretical optimum operating values were obtained and can be implemented to improve the industrial process. Extreme static sensitivity with respect to reboiler heat was observed, indicating that this can be the source of instabilities.

  3. Spectroscopic and computational studies of 1,4-bis[β-(6-tertbutyl-2-benzoxazolyl)vinyl]benzene(BTBVB) laser dye

    International Nuclear Information System (INIS)

    The electronic absorption, fluorescence spectra and photophysical parameters such as, molar absorptivity (ε), oscillator strength (f), transition dipole moment (μ12), and fluorescence quantum yield (φf) of BTBVB were determined in different solvents and micelles. Both electronic absorption and emission spectra are less sensitive to medium polarity which indicates little change in the dipole moment of singlet (S0) ground and excited state (S1) of BTBVB molecule upon excitation. The quantum yield for photochemical transformation (φc) of BTBVB was calculated in different organic solvents such as DMSO, DMF, EtOH and CHCl3 at room temperature. The dye solutions in DMSO, DMF, CHCl3 and EtOH give laser emission in the blue–green region upon excitation by a 337.1 nm nitrogen pulse. The tuning range, gain coefficient (α) and emission cross-section (σe) have been determined. Excitation energy transfer from BTBVB to rhodamine B was studied in n-butanol, methanol and ethylene glycol to improve the laser emission from RB dye when excited by nitrogen laser. Such an energy transfer dye laser system (ETDL) obeys a long range columbic energy transfer mechanism with a critical transfer distance, R0, of 36 Å and kET equal 6×1012 M−1 s−1. The density functional theory (DFT) was used to optimize the ground and excited state geometry of the dye, the computed peaks of absorption and emission spectra are in a reasonable agreement with the experimental results. -- Highlights: • BTBVB dye gives laser emission in blue–green region of visible spectrum with emission maximum at 460 nm, BTBVB dye displays trans–cis isomerisation with low photochemical quantum yield. • BTBVB acts as good energy donor for laser days which have low molar absorptivity at 337 nm (nitrogen laser pulse) and the energy transfer obey Forster mechanism. • BTBVB has the lower λ(e) than that of the λ(h), so it might be good electron transport materials

  4. Spectroscopic and computational studies of 1,4-bis[β-(6-tertbutyl-2-benzoxazolyl)vinyl]benzene(BTBVB) laser dye

    Energy Technology Data Exchange (ETDEWEB)

    El-Daly, Samy A., E-mail: samyeldaly@Yahoo.com [Chemistry Department, Faculty of Science, King Abdulaziz University, PO Box 80203, Jeddah 21589 (Saudi Arabia); Chemistry Department, Faculty of Science, Tanta University, Tanta (Egypt); Asiri, Abdullah M. [Chemistry Department, Faculty of Science, King Abdulaziz University, PO Box 80203, Jeddah 21589 (Saudi Arabia); Center of Excellence for Advanced Materials Research, King Abdulaziz University, PO Box 80203, Jeddah 21589 (Saudi Arabia); Hussein, Mahmoud A. [Chemistry Department, Faculty of Science, King Abdulaziz University, PO Box 80203, Jeddah 21589 (Saudi Arabia); Chemistry Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt); Al-Sehemi, Abdullah G. [Chemistry Department, Faculty of Science, King Khalid University, Abha (Saudi Arabia)

    2014-04-15

    The electronic absorption, fluorescence spectra and photophysical parameters such as, molar absorptivity (ε), oscillator strength (f), transition dipole moment (μ{sub 12}), and fluorescence quantum yield (φ{sub f}) of BTBVB were determined in different solvents and micelles. Both electronic absorption and emission spectra are less sensitive to medium polarity which indicates little change in the dipole moment of singlet (S{sub 0}) ground and excited state (S{sub 1}) of BTBVB molecule upon excitation. The quantum yield for photochemical transformation (φ{sub c}) of BTBVB was calculated in different organic solvents such as DMSO, DMF, EtOH and CHCl{sub 3} at room temperature. The dye solutions in DMSO, DMF, CHCl{sub 3} and EtOH give laser emission in the blue–green region upon excitation by a 337.1 nm nitrogen pulse. The tuning range, gain coefficient (α) and emission cross-section (σ{sub e}) have been determined. Excitation energy transfer from BTBVB to rhodamine B was studied in n-butanol, methanol and ethylene glycol to improve the laser emission from RB dye when excited by nitrogen laser. Such an energy transfer dye laser system (ETDL) obeys a long range columbic energy transfer mechanism with a critical transfer distance, R{sub 0}, of 36 Å and k{sub ET} equal 6×10{sup 12} M{sup −1} s{sup −1}. The density functional theory (DFT) was used to optimize the ground and excited state geometry of the dye, the computed peaks of absorption and emission spectra are in a reasonable agreement with the experimental results. -- Highlights: • BTBVB dye gives laser emission in blue–green region of visible spectrum with emission maximum at 460 nm, BTBVB dye displays trans–cis isomerisation with low photochemical quantum yield. • BTBVB acts as good energy donor for laser days which have low molar absorptivity at 337 nm (nitrogen laser pulse) and the energy transfer obey Forster mechanism. • BTBVB has the lower λ(e) than that of the λ(h), so it might be

  5. Catalytic transformation of methyl benzenes over zeolite catalysts

    KAUST Repository

    Al-Khattaf, S.

    2011-02-01

    Catalytic transformation of three methyl benzenes (toluene, m-xylene, and 1,2,4-trimethyl benzene) has been investigated over ZSM-5, TNU-9, mordenite and SSZ-33 catalysts in a novel riser simulator at different operating conditions. Catalytic experiments were carried out in the temperature range of 300-400 °C to understand the transformation of these alkyl benzenes over large pore (mordenite and SSZ-33) in contrast to medium-pore (ZSM-5 and TNU-9) zeolite-based catalysts. The effect of reaction conditions on the isomerization to disproportionation product ratio, distribution of trimethylbenzene (TMB) isomers, and p-xylene/o-xylene ratios are reported. The sequence of reactivity of the three alkyl benzenes depends upon the pore structure of zeolites. The zeolite structure controls primarily the diffusion of reactants and products while the acidity of these zeolites is of a secondary importance. In the case of medium pore zeolites, the order of conversion was m-xylene > 1,2,4-TMB > toluene. Over large pore zeolites the order of reactivity was 1,2,4-TMB > m-xylene > toluene for SSZ-33 catalyst, and m-xylene ∼ 1,2,4-TMB > toluene over mordenite. Significant effect of pore size between ZSM-5 and TNU-9 was observed; although TNU-9 is also 3D 10-ring channel system, its slightly larger pores compared with ZSM-5 provide sufficient reaction space to behave like large-pore zeolites in transformation of aromatic hydrocarbons. We have also carried out kinetic studies for these reactions and activation energies for all three reactants over all zeolite catalysts under study have been calculated. © 2011 Elsevier B.V.

  6. LED Irradiation of a Photocatalyst for Benzene, Toluene, Ethyl Benzene,and Xylene Decomposition%LED Irradiation of a Photocatalyst for Benzene,Toluene,Ethyl Benzene,and Xylene Decomposition

    Institute of Scientific and Technical Information of China (English)

    JO Wan-Kuen; KANG Hyun-Jung

    2012-01-01

    Studies on the use of gas phase applications of light emitting diodes (LEDs) in photocatalysis are scarce although their photocatalytic decomposition kinetics of environmental pollutants are likely different from those in aqueous solutions.The present study evaluated the use of chips of visible light LEDs to irradiate nitrogen doped titania (N-TiO2) prepared by hydrolysis to decompose gaseous benzene,toluene,ethyl benzene,m-xylene,p-xylene,and o-xylene.Photocatalysts calcined at different temperatures were characterized by various analytical instruments.The degradation efficiency of benzene was close to zero for all conditions.For the other compounds,a conventional 8 W daylight lamp/N-TiO2 unit gave a higher photocatalytic degradation efficiency as compared with that of visible-LED/N-TiO2 units.However,the ratios of degradation efficiency to electric power consumption were higher for the photocatalytic units that used two types of visible-LED lamps (blue and white LEDs).The highest degradation efficiency was observed with the use of a calcination temperature of 350 ℃.The average degradation efficiencies for toluene,ethyl benzene,m-xylene,p-xylene,and o-xylene were 35%,68%,94%,and 93%,respectively.The use of blue-and white-LEDs,high light intensity,and low initial concentrations gave high photocatalytic activities for the photocatalytic units using visible-LEDs.The morphological and optical properties of the photocatalysts were correlated to explain the dependence of photocatalytic activity on calcination temperature.The results suggest that visible-LEDs are energy efficient light source for photocatalytic gas phase applications,but the activity depends on the operational conditions.

  7. Influence of Benzene on the Optical Properties of Titan Haze Laboratory Analogs in the Mid-Visible

    Science.gov (United States)

    Yoon, Y. Heidi; Trainer, Melissa G.; Tolbert, Margaret A.

    2012-01-01

    The Cassini Ion and Neutral Mass Spectrometer (Waite, Jr., et al., 2007) and the Composite Infrared Spectrometer (Coustenis, A., et al., 2007) have detected benzene in the upper atmosphere and stratosphere of Titan. Photochemical reactions involving benzene in Titan's atmosphere may influence polycyclic aromatic hydrocarbon formation, aerosol formation, and the radiative balance of Titan's atmosphere. We measure the effect of benzene on the optical properties of Titan analog particles in the laboratory. Using cavity ring-down aerosol extinction spectroscopy, we determine the real and imaginary refractive index at 532 nm of particles formed by benzene photolysis and Titan analog particles formed with ppm-levels of benzene. These studies are compared to the previous study by Hasenkopf, et a1. (2010) of Titan analog particles formed by methane photolysis.

  8. Protective effects of zinc and selenium against benzene toxicity in rats.

    Science.gov (United States)

    Ibrahim, Khadiga S; Saleh, Zeinab A; Farrag, Abdel-Razik H; Shaban, Eman E

    2011-07-01

    The presented study investigates the protective role of zinc (Zn) and selenium (Se) in attenuating benzene-induced toxicity in rats. Male Sprague-Dawley rats were injected with benzene (0.5 mL/kg body weight ip) and received a diet supplement containing Zn and Se. Several hematological and biochemical parameters (representing antioxidant status) were estimated. Histopathological examinations were performed. Results showed that food intake and body weight gain of benzene-injected rats were significantly lower than that of the control rats. Benzene-injected rats showed increased plasma malondialdehyde (MDA) and decreased activity of: glutathione peroxidase (GSH-Px), catalase, superoxide dismutase (SOD) enzymes, as well as reduced glutathione (GSH) when compared to the control group. Histopathological investigations revealed structural changes in benzene-injected rats' liver. Supplementation with Zn and Se resulted in a significant decrease in MDA, elevation in GSH, GSH-Px, SOD and catalase levels. This study shows that Zn and Se supplementation can improve the activity of antioxidant enzymes in rats and decrease the histological anomalies induced by benzene toxicity as well. PMID:21511895

  9. Experimental geothermal research facilities study (Phase 0). Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    1974-01-01

    The study comprises Phase 0 of a project for Experimental Geothermal Research Facilities. The study focuses on identification of a representative liquid-dominated geothermal reservoir of moderate temperature and salinity, preliminary engineering design of an appropriate energy conversion system, identification of critical technology, and planning for implementation of experimental facilities. The objectives included development of liaison with the industrial sector, to ensure responsiveness to their views in facility requirements and planning, and incorporation of environmental and socioeconomic factors. This Phase 0 report covers problem definition and systems requirements. Facilities will incorporate capability for research in component, system, and materials technology and a nominal 10 MWe experimental, binary cycle, power generating plant.

  10. Experimental Study on the Langlee Wave Energy Converter

    DEFF Research Database (Denmark)

    Lavelle, John; Kofoed, Jens Peter

    This report concerns the experimental study of the 1:20 scale model of the Langlee Wave Energy Converter (WEC) carried out at Aalborg University’s wave basin during the summer of 2010.......This report concerns the experimental study of the 1:20 scale model of the Langlee Wave Energy Converter (WEC) carried out at Aalborg University’s wave basin during the summer of 2010....

  11. Adsorption Of Water And Benzene Vapour In Mesoporous Materials

    Directory of Open Access Journals (Sweden)

    Paulina Taba

    2008-11-01

    Full Text Available Mesoporous materials have attracted the attention of many researchers due to the potential applications promised by the materials. This article discusses adsorption of water and benzene vapour in mesoporous materials (mesoporous silica: MCM-41, MCM-48 and their modification. MCM-41 and MCM-48 were synthesized hydrothermally at 100 oC using cethyltrimethylammonium chloride or dodecyltrimethylammonium bromide for MCM-41 (C16 or MCM-41 (C12 respectively and a mixture of cethyltrimethylammonium bromide and Triton X-100 for MCM-48 as templates. Their modifications were conducted by silylation of MCM-41 (C16 and MCM-48 with trimethylchloro silane (MCM16-TMCS and MCM48-TMCS and t-butyldimethylchloro silane (MCM16-TBDMCS and MCM48-TBDMCS. Results showed that MCM-41 and MCM-48 materials had hydrophobic features which were shown in the small amount of water adsorption at low P/P0. The hydrophobicity of samples used in this study decrease in the sequence: MCM-41 (C16 > MCM-48 > MCM-41 (C12. The hydrophobicity increased when MCM-41 and MCM-48 were silylated with TMCS or TBDMCS. All unsilylated MCM materials show higher affinity to benzene at low P/P0 than the silylated samples. The results of water and benzene adsorption showed that silylated samples are promising candidates as selective adsorbents for organic compounds.

  12. Standard reference data for the air-liquid and vapor-liquid surface tension of benzene

    Czech Academy of Sciences Publication Activity Database

    Součková, Monika; Klomfar, Jaroslav; Pátek, Jaroslav

    2013-01-01

    Roč. 356, October (2013), s. 329-337. ISSN 0378-3812 R&D Projects: GA ČR GA101/09/0010 Institutional support: RVO:61388998 Keywords : benzene * surface tension * experimental data * standard reference data Subject RIV: BJ - Thermodynamics Impact factor: 2.241, year: 2013 http://www.sciencedirect.com/science/article/pii/S0378381213004196

  13. Kinetic model of deactivation of a nickel catalyst in the reaction of hydrogenation of benzene

    Energy Technology Data Exchange (ETDEWEB)

    Masagutov, R.M.; Spivak, S.I.; Kovaleva, L.V.; Morozov, B.V.; Yaropolova, E.A.

    1988-12-01

    The kinetics of hydrogenation of benzene on a nickel catalyst in conditions of poisoning with thiophene were investigated. A mechanism of deactivation of the catalyst was proposed. A kinetic model of the process was constructed. The numerical values of the constants of the deactivation stages which satisfactorily describe the experimental data were found.

  14. The pyrolysis of toluene and ethyl benzene

    Science.gov (United States)

    Sokolovskaya, V. G.; Samgin, V. F.; Kalinenko, R. A.; Nametkin, N. S.

    1987-01-01

    The pyrolysis of toluene at 850 to 950 C gave mainly H2, CH4, and benzene; PhEt at 650 to 750 C gave mainly H2, CH4, styrene, benzene, and toluene. The rate constants for PhEt pyrolysis were 1000 times higher than those for toluene pyrolysis; the chain initiation rate constants differed by the same factor. The activation energy differences were 46 kJ/mole for the total reaction and 54 kJ/mole for chain initiation. The chain length was evaluated for the PhEt case (10 + or - 2).

  15. Experimental study on the characteristics of semiconductor opening switch

    CERN Document Server

    Su Jian Cang; Ding Yong Zhong; Song Zhi Min; Ding Zhen Jie; Liu Guo Zhi

    2002-01-01

    An experimental set-up is developed to measure the characteristics of semiconductor opening switch (SOS). The parameters, such as interruption impedance, current int eruption time, voltage gain, pulse duration and energy transfer efficiency, are studied experimentally. The experimental results show that forward pumping time and reverse pumping time are important parameters for semiconductor opening switches. The influences of forward pumping time and reverse pumping time on interruption time, voltage gain, and energy transfer efficiency are obtained. In the interruption process, the impedance variation is divided into three phases: that is rapid increasing phase, slow change phase and completely interruption phase

  16. Experimental Method For Studying Habitual Behavior In Food Consumption

    OpenAIRE

    Naziha Kasraoui

    2015-01-01

    Abstract To investigate the process of habit formation in everyday life a sample of 126 participants students chooses an eating and drinking for three periods weeks. They completed the self-report habit each period and we have recorded their choices. All participants provided sufficient data for analysis and collected experimental data were examined over the study periods 3 weeks. Experimental analysis was used to examine the persistence of habit formation process in the behavior of participa...

  17. The false memory syndrome: Experimental studies and comparison to confabulations

    OpenAIRE

    Mendez, M F; Fras, I.A.

    2010-01-01

    False memories, or recollections that are factually incorrect but strongly believed, remain a source of confusion for both psychiatrists and neurologists. We propose model for false memories based on recent experimental investigations, particularly when analyzed in comparison to confabulations, which are the equivalent of false memories from neurological disease. Studies using the Deese/Roedinger–McDermott experimental paradigm indicate that false memories are associated with the need for com...

  18. Intermediates in the hydrogenation of benzene to cyclohexene on Pt(1 1 1) and Pd(1 1 1): A comparison from DFT calculations

    Science.gov (United States)

    Morin, C.; Simon, D.; Sautet, P.

    2006-03-01

    Catalytic hydrogenation of aromatic compounds is an important process in petroleum industry. Understanding it through experimental or theoretical research can help to improve its efficiency. This work presents a first principles density functional theory study of the intermediates for the first four hydrogenations steps of the smallest aromatic compound, benzene, into C 6H 10 species, on two popular catalytic metals, palladium and platinum, described by periodic models. Different structures have been studied for the intermediate C 6H 6+ n species, with a various degree of conservation of the conjugation. Some intermediates would present in gas phase a closed-shell conjugated structure, while other would correspond to multiple radicals with a massive destruction of the benzene π system. The Pd and Pt(1 1 1) surfaces strongly differ in terms of most stable structure for the intermediates. On Pd the most conjugated intermediates, i.e. the most stable in gas phase, is clearly preferred. In contrast, on Pt, multiple radical species, highly unstable in gas phase, are strongly stabilized by coupling with the surface. This thermodynamic study indicates a different trend for the hydrogenation mechanism: a clear successive 1-2-3… hydrogenation of neighboring carbon atoms on Pd keeping the largest conjugated fragment, and a nonconsecutive attack, with a maximum breaking of benzene conjugation on Pt.

  19. Recommended sublimation pressure and enthalpy of benzene

    Czech Academy of Sciences Publication Activity Database

    Růžička, K.; Fulem, Michal; Červinka, C.

    2014-01-01

    Roč. 68, Jan (2014), s. 40-47. ISSN 0021-9614 Institutional support: RVO:68378271 Keywords : benzene * vapor pressure * heat capacity * ideal-gas thermodynamic properties * sublimation enthalpy * recommended vapor pressure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.679, year: 2014

  20. 46 CFR 153.1060 - Benzene.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Benzene. 153.1060 Section 153.1060 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Special Cargo Procedures § 153.1060...

  1. Formation of Benzene in the Interstellar Medium

    Science.gov (United States)

    Jones, Brant M.; Zhang, Fangtong; Kaiser, Ralf I.; Jamal, Adeel; Mebel, Alexander M.; Cordiner, Martin A.; Charnley, Steven B.; Crim, F. Fleming (Editor)

    2010-01-01

    Polycyclic aromatic hydrocarbons and related species have been suggested to play a key role in the astrochemical evolution of the interstellar medium, but the formation mechanism of even their simplest building block-the aromatic benzene molecule-has remained elusive for decades. Here we demonstrate in crossed molecular beam experiments combined with electronic structure and statistical calculations that benzene (C6H6) can be synthesized via the barrierless, exoergic reaction of the ethynyl radical and 1,3- butadiene, C2H + H2CCHCHCH2 --> C6H6, + H, under single collision conditions. This reaction portrays the simplest representative of a reaction class in which aromatic molecules with a benzene core can be formed from acyclic precursors via barrierless reactions of ethynyl radicals with substituted 1,3-butadlene molecules. Unique gas-grain astrochemical models imply that this low-temperature route controls the synthesis of the very first aromatic ring from acyclic precursors in cold molecular clouds, such as in the Taurus Molecular Cloud. Rapid, subsequent barrierless reactions of benzene with ethynyl radicals can lead to naphthalene-like structures thus effectively propagating the ethynyl-radical mediated formation of aromatic molecules in the interstellar medium.

  2. An experimental study into the bilinear oscillator close to grazing

    Energy Technology Data Exchange (ETDEWEB)

    Ing, J; Pavlovskaia, E; Wiercigroch, M [Centre for Applied Dynamics Research, Department of Engineering, King' s College, University of Aberdeen, Aberdeen, AB24 3UE (United Kingdom)], E-mail: j.ing@abdn.ac.uk

    2008-02-15

    A linear oscillator undergoing impact with a secondary support is studied experimentally. Smooth as well as nonsmooth bifurcations are observed. The bifurcations are explained with help from simulations based on mapping solutions between locally smooth subspaces. Experimental stability studies are also presented, justifying the normal form maps used to show the response close to grazing for systems with and without prestress of the secondary spring. The high degree of correspondence lends support to the modelling approach, and the highly complicated response justifies continued study of this system.

  3. An experimental study into the bilinear oscillator close to grazing

    International Nuclear Information System (INIS)

    A linear oscillator undergoing impact with a secondary support is studied experimentally. Smooth as well as nonsmooth bifurcations are observed. The bifurcations are explained with help from simulations based on mapping solutions between locally smooth subspaces. Experimental stability studies are also presented, justifying the normal form maps used to show the response close to grazing for systems with and without prestress of the secondary spring. The high degree of correspondence lends support to the modelling approach, and the highly complicated response justifies continued study of this system

  4. An experimental study into the bilinear oscillator close to grazing

    Science.gov (United States)

    Ing, J.; Pavlovskaia, E.; Wiercigroch, M.

    2008-02-01

    A linear oscillator undergoing impact with a secondary support is studied experimentally. Smooth as well as nonsmooth bifurcations are observed. The bifurcations are explained with help from simulations based on mapping solutions between locally smooth subspaces. Experimental stability studies are also presented, justifying the normal form maps used to show the response close to grazing for systems with and without prestress of the secondary spring. The high degree of correspondence lends support to the modelling approach, and the highly complicated response justifies continued study of this system.

  5. Contrastive Analysis of the Raman Spectra of Polychlorinated Benzene: Hexachlorobenzene and Benzene

    Directory of Open Access Journals (Sweden)

    Zhengjun Zhang

    2011-12-01

    Full Text Available Detection of persistent pollutants such as polychlorinated benzene in environment in trace amounts is challenging, but important. It is more difficult to distinguish homologues and isomers of organic pollutantd when present in trace amounts because of their similar physical and chemical properties. In this work we simulate the Raman spectra of hexachlorobenzene and benzene, and figure out the vibration mode of each main peak. The effect on the Raman spectrum of changing substituents from H to Cl is analyzed to reveal the relations between the Raman spectra of homologues and isomers of polychlorinated benzene, which should be helpful for distinguishing one kind of polychlorinated benzene from its homologues and isomers by surface enhanced Raman scattering.

  6. 40 CFR 721.1350 - Benzene, (1-methylethyl)(2-phenylethyl)-.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, (1-methylethyl)(2-phenylethyl... Substances § 721.1350 Benzene, (1-methylethyl)(2-phenylethyl)-. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified as benzene,...

  7. 40 CFR 721.1210 - Benzene, (2-chloroethoxy)-.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, (2-chloroethoxy)-. 721.1210... Substances § 721.1210 Benzene, (2-chloroethoxy)-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as benzene, (2-chloroethoxy)- (PMN P-87-1471) is subject...

  8. 40 CFR 721.1187 - Bis(imidoethylene) benzene.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Bis(imidoethylene) benzene. 721.1187... Substances § 721.1187 Bis(imidoethylene) benzene. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance bis(imidoethylene)benzene (PMN P-93-1447) is subject to...

  9. Characterization of a 1:1 Methanol-Benzene Complex Using Matrix Isolation Infrared Spectroscopy

    Science.gov (United States)

    Amicangelo, Jay C.; Romano, Natalie C.; Demay, Geoffrey R.

    2013-06-01

    Matrix isolation infrared spectroscopy was used to characterize a 1:1 complex of methanol (CH_{3}OH) with benzene (C_{6}H_{6}). Co-deposition experiments with CH_{3}OH and C_{6}H_{6} were performed at 17 - 20 K using nitrogen and argon as the matrix gases. New infrared bands attributable to the CH_{3}OH-C_{6}H_{6} complex were observed near the O-H and C-O stretching vibrations of CH_{3}OH and near the hydrogen out-of-plane bending vibration of C_{6}H_{6}. The initial identification of the new infrared bands observed was established by performing a conentration study (1:200 to 1:2000 S:M ratios), by comparing the co-deposition spectra with the spectra of the individual monomers, by matrix annealing experiments, and by performing experiments using isotopically labeled methanol (CD_{3}OD) and benzene (C_{6}D_{6}). Quantum chemical calculations were also performed for the CH_{3}OH-C_{6}H_{6} complex using density functional theory and ab initio methods. Two stable minima were found for the complex: one in which the CH_{3}OH is above the C_{6}H_{6} ring with the hydroxyl hydrogen interacting with the π cloud of the ring (H-π complex) and the other in which the CH_{3}OH is in the plane of the C_{6}H_{6} ring with the hydroxyl oxygen interacting with one of the C-H bonds of the ring (CH-O complex). Comparing the calculated shifts of the vibrational frequencies for both complexes to the observed experimental frequency shifts, it is found that the H-π complex is in best agreement with the experimental shifts in both magnitude and direction. Therefore, it is concluded that the geometry of the CH_{3}OH-C_{6}H_{6} complex observed in the matrix isolation experiments is the H-π complex.

  10. PDMS渗透蒸发膜分离稀水溶液中苯的模型研究%Modeling of Pervaporation Separation Benzene from Dilute Aqueous Solutions Through Polydimethylsiloxane Membranes

    Institute of Scientific and Technical Information of China (English)

    彭福兵; 姜忠义

    2005-01-01

    A modified solution-diffusion model was established based on Flory-Huggins thermodynamic theory and Fujita's free volume theory. This model was used for description of the mass transfer of removal benzene from dilute aqueous solutions through polydimethylsiloxane (PDMS) membranes. The effect of component concentration on the interaction parameter between components, that of the polymer membrane on the selectivity to benzene, and that of feed concentration and temperature on the permeation flux and separation factor of benzene/water through PDMS membranes were investigated. Calculated pervaporation fluxes of benzene and water were compared with the experimental results and were in good agreement with the experimental data.

  11. Analytical and Experimental Study of Residual Stresses in CFRP

    Directory of Open Access Journals (Sweden)

    Chia-Chin Chiang

    2013-01-01

    Full Text Available Fiber Bragg Grating sensors (FBGs have been utilized in various engineering and photoelectric fields because of their good environment tolerance. In this research, residual stresses of carbon fiber reinforced polymer composites (CFRP were studied using both experimental and analytical approach. The FBGs were embedded inside middle layers of CFRP to study the formation of residual stress during curing process. Finite element analysis was performed using ABAQUS software to simulate the CFRP curing process. Both experimental and simulation results showed that the residual stress appeared during cooling process and the residual stresses could be released when the CFRP was machined to a different shape.

  12. Experimental study of interband and intraband crosstalk in WDM networks

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The impacts of interband and intraband crosstalk are studied and compared experimentally. Results show that interband crosstalk can be removed with narrow-band filters and has no influence on signal. Intraband crosstalk will result in signal eye diagram close and BER increasing. When the polarization states of signal and crosstalk align, intraband crosstalk seriously decreases signal quality. But when they misalign, it has little influence. Coherent and incoherent crosstalk are studied experimentally. Results show that coherent crosstalk is less harmful to system performance than incoherent crosstalk.

  13. Diffusion in liquids a theoretical and experimental study

    CERN Document Server

    Tyrrell, H J V

    1984-01-01

    Diffusion in Liquids: A Theoretical and Experimental Study aims to discuss the principles, applications, and advances in the field of diffusion, thermal diffusion, and thermal conduction in liquid systems. The book covers topics such as the principles of non-equilibrium thermodynamics; diffusion in binary and multicompetent systems; and experimental methods of studying diffusion processes in liquids. Also covered in the book are topics such as the theoretical interpretations of diffusion coefficients; hydrodynamic and kinetic theories; and diffusion in electrolyte systems. The text is recommen

  14. Experimental studies of antikaon mediated bound nuclear systems

    International Nuclear Information System (INIS)

    Recent experimental studies of the synthesis and properties of deeply bound antikaon mediated nuclear systems are reviewed. Following a brief introduction in the basic properties of the antikaon–nucleon interaction which may lead to cold and dense antikaonic nuclear systems, we review the results of very first experiments which give indications of the existence of such exotic clusters of matter. Then ongoing efforts to substantiate the early findings are presented and future experimental approaches which will allow a very detailed study of the decay modes, the sizes and density distributions of these kaonic nuclear clusters are discussed including their relevance for possible phase transitions in cold dense matter. (author)

  15. Benzene and lead exposure assessment among occupational bus drivers in Bangkok traffic

    Institute of Scientific and Technical Information of China (English)

    SHING TET LEONG; PREECHA LAORTANAKUL

    2004-01-01

    Four environmental and biological monitoring sites were strategically established to evaluate benzene and lead exposure assessment at various traffic zones of Bangkok Metropolitan Region(BMR). Biological measurement of 48 non air-conditioned, male bus drivers was carried to study the relationship between individual exposure levels and exposure biomarkers. The study group was further subdivided into four age groups( 16-25, 26-35, 36-45 and 46-55 years old) to monitor the age-related exposure effects. A total of 12unexposed persons were deliberately chosen as the control group. Measurement of unmetobolized benzene in blood and analysis of urinary tt-Muconic acid urine and urinary creatinine are recommended as biomarkers of benzene exposure. Measurement of lead in blood and urine is also recommended for the biological monitoring of lead exposure.During the monitoring period, benzene and lead levels at Yaowarat Road was C6H6: 42.46 + 3.88 μg/m3 , Pb: 0.29 + 0.03 μg/m3 and decreased to C6 H6: 33.5 ± 1.35 μg/m3 , Pb: O. 13 + 0.01 μg/m3 at Phahonyothin Road. Significant difference was established between the nonsmoking exposed group and nonsmoking control group for blood benzene concentrations ( P < 0.001, two-tailed, Mann-Whiteney U test). Strong correlations were also found between trans-trans-Muconic acid concentrations in post shift samples and atmospheric benzene concentrations. Similarly, good correlation between all of biomarkers and lead level in air is established from automobile emissions.The analysis revealed that among the occupational population in the urban sites, the driver groups were found to have the highest risk of benzene and lead exposures derived from automobile emission.

  16. Benzene and lead exposure assessment among occupational bus drivers in Bangkok traffic.

    Science.gov (United States)

    Muttamara, S; Leong, Shing Tet; Arayasiri, M

    2004-01-01

    Four environmental and biological monitoring sites were strategically established to evaluate benzene and lead exposure assessment at various traffic zones of Bangkok Metropolitan Region(BMR). Biological measurement of 48 non air-conditioned, male bus drivers was carried to study the relationship between individual exposure levels and exposure biomarkers. The study group was further subdivided into four age groups(16-25, 26-35, 36-45 and 46-55 years old) to monitor the age-related exposure effects. A total of 12 unexposed persons were deliberately chosen as the control group. Measurement of unmetobolized benzene in blood and analysis of urinary tt-Muconic acid urine and urinary creatinine are recommended as biomarkers of benzene exposure. Measurement of lead in blood and urine is also recommended for the biological monitoring of lead exposure. During the monitoring period, benzene and lead levels at Yaowarat Road was C6H6: 42.46 +/- 3.88 microg/m3 , Pb: 0.29 +/- 0.03 microg/m3 and decreased to C6H6: 33.5 +/- 1.35 microg/m3, Pb: 0.13 +/- 0.01 microg/m3 at Phahonyothin Road. Significant difference was established between the nonsmoking exposed group and nonsmoking control group for blood benzene concentrations (P < 0.001, two-tailed, Mann-Whiteney U test). Strong correlations were also found between trans-trans-Muconic acid concentrations in post shift samples and atmospheric benzene concentrations. Similarly, good correlation between all of biomarkers and lead level in air is established from automobile emissions. The analysis revealed that among the occupational population in the urban sites, the driver groups were found to have the highest risk of benzene and lead exposures derived from automobile emission. PMID:14971454

  17. Characterization of changes in gene expression and biochemical pathways at low levels of benzene exposure.

    Directory of Open Access Journals (Sweden)

    Reuben Thomas

    Full Text Available Benzene, a ubiquitous environmental pollutant, causes acute myeloid leukemia (AML. Recently, through transcriptome profiling of peripheral blood mononuclear cells (PBMC, we reported dose-dependent effects of benzene exposure on gene expression and biochemical pathways in 83 workers exposed across four airborne concentration ranges (from 10 ppm compared with 42 subjects with non-workplace ambient exposure levels. Here, we further characterize these dose-dependent effects with continuous benzene exposure in all 125 study subjects. We estimated air benzene exposure levels in the 42 environmentally-exposed subjects from their unmetabolized urinary benzene levels. We used a novel non-parametric, data-adaptive model selection method to estimate the change with dose in the expression of each gene. We describe non-parametric approaches to model pathway responses and used these to estimate the dose responses of the AML pathway and 4 other pathways of interest. The response patterns of majority of genes as captured by mean estimates of the first and second principal components of the dose-response for the five pathways and the profiles of 6 AML pathway response-representative genes (identified by clustering exhibited similar apparent supra-linear responses. Responses at or below 0.1 ppm benzene were observed for altered expression of AML pathway genes and CYP2E1. Together, these data show that benzene alters disease-relevant pathways and genes in a dose-dependent manner, with effects apparent at doses as low as 100 ppb in air. Studies with extensive exposure assessment of subjects exposed in the low-dose range between 10 ppb and 1 ppm are needed to confirm these findings.

  18. Diffusion and adsorption of benzene in Regina clay

    International Nuclear Information System (INIS)

    Surface or near-surface spills of hydrocarbons such as gasoline and diesel often occur in clay soils which are fractured and unsaturated. For cost-effective remediation, the extent of contamination and the distribution of the various phases should be determined before the development of remediation methods. The four volatile compounds that are commonly associated with gasoline leaking from underground fuel storage tanks are benzene, toluene, ethlybenzene and xylene. Existing diffusion test methods have been used successfully for inorganic species, but the successful application of these methods to volatile organic compounds is limited. The main difficulty with experiments using volatile organics is that there is a need for careful sample handling and sensitive analytical methods to accurately measure the aqueous concentration. Work was carried out to develop an apparatus that could be used to measure the diffusion and adsorption of volatile organics in clay. The best visual fit to the experimental data for the single reservoir test was an effective diffusion coefficient of 0.01 mL/g, and an adsorption coefficient of 0.1 mL/g. Based on diffusion cell tests, there are relatively low levels of retardation for benzene as it moves in clay soils with low organic carbon content. The implications for remediation are summarized. 28 refs., 16 figs., 5 tabs

  19. RC Columns Strengthened with Novel CFRP Systems: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Annalisa Napoli

    2015-10-01

    Full Text Available This paper presents an experimental study undertaken to investigate the seismic behavior of full scale square (300 mm × 300 mm reinforced concrete (RC columns strengthened with novel systems employing carbon fiber-reinforced polymers (CFRP wraps. Experimental tests were carried out by subjecting specimens to a constant axial load and a cyclically reversed horizontal force applied in displacement control. Results have allowed for investigating the influence of the used strengthening systems on the specimens’ performance in terms of flexural strength and ductility as well as on the exhibited failure modes. The effectiveness of the studied techniques is also evaluated by comparing the performance of tested specimens with that of companion columns strengthened with alternative CFRP systems investigated in a previous experimental campaign.

  20. Experimental studies of electron-phonon interactions in gallium nitride

    OpenAIRE

    Stanton, Nicola Marie

    2001-01-01

    This thesis presents an experimental investigation of the electron-phonon interaction in GaN. Bulk epilayers, grown by MBE, and AIGaN/GaN heterostructures, grown by MOCVD, have been studied. The energy relaxation rate for hot electrons has been measured over a wide range of temperatures, allowing both acoustic and optic phonon emission to be studied in GaN epilayers. Direct phonon measurements, both studying the emission and absorption processes, have been performed. Detection of phonons e...

  1. Computational and Experimental Study of an Industrial Centrifugal Compressor Volute

    Institute of Scientific and Technical Information of China (English)

    HarriPitkanen; HannuEsa; 等

    2000-01-01

    A centrifugal compressor with a vaneless diffuser was studied experimentally and numericallly.The main target of the study was to analyze the volute flow.Two different volute geometries was studied.The numerical solution was done by using a steady-state RANS code at both design and off-design conditions.Both calculated and measured pressure and velocity distributions are presented.

  2. Experimental study of bulk storage ignition by hot points

    OpenAIRE

    Janes, Agnès; Carson, Douglas

    2013-01-01

    International audience An experimental study of ignition risk due to hot points in the storage of bulk materials is required to ensure fire safety. Many parameters are involved in this phenomenon: nature of the material, storage volume and temperature, type and size of hot point, etc. The aim of this study is to determine critical ignition temperatures of hot spots embedded in powder materials for different conditions and with several types of hot points. Materials selected for this study ...

  3. Treatment of helicobacter pylori infection : Experimental and clinical studies

    OpenAIRE

    Sörberg, Mikael

    1997-01-01

    Treatment of Helicobacter Pylori Infection Experimental and Clinical Studies Mikael Sörberg, Division of Infectious Diseases, Karolinska Institutet Danderyd Hospital, S-182 88 Danderyd, Sweden The general aims of the present study were to investigate the reason for failed H. pylori eradication, and to improve the recommendations for treating H. pylori infection. Our in vitro studies are based on microscopy, viable count and bioluminescence assay of bacterial adenos...

  4. Study of application of alumina-coated carbon nanotube for removal of Hydroxy Benzene from aqueous solutions: Adsorption and determination of equilibrium and kinetics parameters

    Directory of Open Access Journals (Sweden)

    M Malakootian

    2015-08-01

    Full Text Available Background and Objective: Phenol and phenol derivatives in industrial wastewater are among the pollutants with priorities. The high cost and low efficiency of some routine treatment processes of industrial wastewater has limited their use. One of the new methods under consideration is, nowadays, adsorption using carbon nanotubes. This study was conducted in order to evaluate the application of alumina-coated multiwall carbon nanotubes in eliminating phenol from synthetic wastewater. Materials and Methods: This study was performed in laboratory at batch scale. Multi-wall carbon nanotubes were coated with Alumina. The concentration of phenol was determined by spectrophotometer through photometry. The effect of pH changes, dosage of adsorbent, contact time, the initial concentration of phenol, temperature, and the concentrations of different salts on the efficiency of absorption was evaluated. Then, the absorption results were described using the Langmuir and Freundlich isotherms and the synthetics of absorption. Results: It was found that absorption efficiency increased significantly by decreasing the initial concentration of phenol and pH and by increasing the carbon nanotube dosage, temperature, and contact time. On the other hand, the maximum elimination of phenol from the solution (98.86% occurred at 4 mg/l phenol concentration, under acidic conditions (pH=3, at adsorbent dosage of 0.05 g/l, at temperature of 45°C, and contact time of 10 min. Evaluation of the regressions isotherms showed that the process follows the Langmuir model and second-degree synthetic absorption. Conclusion: The high efficacy (98% of the adsorption process in this study showed that alumina-coated multiwall carbon nanotubes have a good capability in eliminating phenol and can be used as an appropriate and new method for eliminating phenol and its derivatives from wastewater.

  5. Comparison of hematological alterations and markers of B-cell activation in workers exposed to benzene, formaldehyde and trichloroethylene.

    Science.gov (United States)

    Bassig, Bryan A; Zhang, Luoping; Vermeulen, Roel; Tang, Xiaojiang; Li, Guilan; Hu, Wei; Guo, Weihong; Purdue, Mark P; Yin, Songnian; Rappaport, Stephen M; Shen, Min; Ji, Zhiying; Qiu, Chuangyi; Ge, Yichen; Hosgood, H Dean; Reiss, Boris; Wu, Banghua; Xie, Yuxuan; Li, Laiyu; Yue, Fei; Freeman, Laura E Beane; Blair, Aaron; Hayes, Richard B; Huang, Hanlin; Smith, Martyn T; Rothman, Nathaniel; Lan, Qing

    2016-07-01

    Benzene, formaldehyde (FA) and trichloroethylene (TCE) are ubiquitous chemicals in workplaces and the general environment. Benzene is an established myeloid leukemogen and probable lymphomagen. FA is classified as a myeloid leukemogen but has not been associated with non-Hodgkin lymphoma (NHL), whereas TCE has been associated with NHL but not myeloid leukemia. Epidemiologic associations between FA and myeloid leukemia, and between benzene, TCE and NHL are, however, still debated. Previously, we showed that these chemicals are associated with hematotoxicity in cross-sectional studies of factory workers in China, which included extensive personal monitoring and biological sample collection. Here, we compare and contrast patterns of hematotoxicity, monosomy 7 in myeloid progenitor cells (MPCs), and B-cell activation biomarkers across these studies to further evaluate possible mechanisms of action and consistency of effects with observed hematologic cancer risks. Workers exposed to benzene or FA, but not TCE, showed declines in cell types derived from MPCs, including granulocytes and platelets. Alterations in lymphoid cell types, including B cells and CD4+ T cells, and B-cell activation markers were apparent in workers exposed to benzene or TCE. Given that alterations in myeloid and lymphoid cell types are associated with hematological malignancies, our data provide biologic insight into the epidemiological evidence linking benzene and FA exposure with myeloid leukemia risk, and TCE and benzene exposure with NHL risk. PMID:27207665

  6. Bioremediation of benzene-, MTBE- and ammonia-contaminated groundwater with pilot-scale constructed wetlands

    International Nuclear Information System (INIS)

    In this pilot-scale constructed wetland (CW) study for treating groundwater contaminated with benzene, MTBE, and ammonia-N, the performance of two types of CWs (a wetland with gravel matrix and a plant root mat) was investigated. Hypothesized stimulative effects of filter material additives (charcoal, iron(III)) on pollutant removal were also tested. Increased contaminant loss was found during summer; the best treatment performance was achieved by the plant root mat. Concentration decrease in the planted gravel filter/plant root mat, respectively, amounted to 81/99% for benzene, 17/82% for MTBE, and 54/41% for ammonia-N at calculated inflow loads of 525/603 mg/m2/d, 97/112 mg/m2/d, and 1167/1342 mg/m2/d for benzene, MTBE, and ammonia-N. Filter additives did not improve contaminant depletion, although sorption processes were observed and elevated iron(II) formation indicated iron reduction. Bacterial and stable isotope analysis provided evidence for microbial benzene degradation in the CW, emphasizing the promising potential of this treatment technique. - Highlights: → BTEX compounds contaminated groundwater can be efficiently treated by CWs. → The removal efficiency depended on CW type, season and contaminant. → The plant root mat revealed better treatment results than the gravel filter CW. → Best results achieved by the plant root mat (99% benzene concentration decrease). → Stable isotope analysis and MPN indicated high benzene remediation potential. - Gravel bed constructed wetlands and a plant root mat system efficiently eliminated fuel hydrocarbons (benzene, MTBE) and ammonia-N from groundwater at a pilot-scale.

  7. Electronic Texts or Learning through Textbooks: An Experimental Study

    Science.gov (United States)

    Cartes-Enriquez, Ninette; Rodriguez, M. I. Solar; Letelier, R. Quintana

    2004-01-01

    This is an experimental study in the area of Didactics applied to the learning of English as a foreign language and complemented by CALL. The main objective of this work is to know the degree of incidence existing between two groups of students: one, based on conference-style classes where students, guided by the teacher, have to search for…

  8. SMS as a Learning Tool: An Experimental Study

    Science.gov (United States)

    Plana, Mar Gutiérrez-Colon; Torrano, Pere Gallardo; Grova, M. Elisa

    2012-01-01

    The aim of this experimental study was to find out the potential of using mobile phones in teaching English as a foreign language (EFL), specifically the use of Short Message Service (SMS) as a support tool in the EFL class. The research questions formulated for this project are the following: (1) Is using SMS messages via a mobile phone an…

  9. Theoretical and experimental studies of a plasma- and particle accelerator

    International Nuclear Information System (INIS)

    Using the combination of a coaxial plasma accelerator with a compression coil a dense and fast plasma flow can be produced and applied for gas-dynamical acceleration of particles. The theoretical and experimental studies presented here contribute to a better understanding of the acceleration process and to the operational application of the system as a micrometeor simulator. (orig.)

  10. Can Facebook Make Students Remember? An Experimental Study from Japan

    Science.gov (United States)

    Acar, Adam

    2014-01-01

    This study experimentally manipulated the way students submit their assignments and tested the number of new words that are learned in each condition. The results showed that students who submitted their assignments through Facebook learned as much as those who submitted their assignment in a traditional way. In the light of these findings, we can…

  11. Real versus Simulated Mobile Phone Exposures in Experimental Studies

    Directory of Open Access Journals (Sweden)

    Dimitris J. Panagopoulos

    2015-01-01

    Full Text Available We examined whether exposures to mobile phone radiation in biological/clinical experiments should be performed with real-life Electromagnetic Fields (EMFs emitted by commercially available mobile phone handsets, instead of simulated EMFs emitted by generators or test phones. Real mobile phone emissions are constantly and unpredictably varying and thus are very different from simulated emissions which employ fixed parameters and no variability. This variability is an important parameter that makes real emissions more bioactive. Living organisms seem to have decreased defense against environmental stressors of high variability. While experimental studies employing simulated EMF-emissions present a strong inconsistency among their results with less than 50% of them reporting effects, studies employing real mobile phone exposures demonstrate an almost 100% consistency in showing adverse effects. This consistency is in agreement with studies showing association with brain tumors, symptoms of unwellness, and declines in animal populations. Average dosimetry in studies with real emissions can be reliable with increased number of field measurements, and variation in experimental outcomes due to exposure variability becomes less significant with increased number of experimental replications. We conclude that, in order for experimental findings to reflect reality, it is crucially important that exposures be performed by commercially available mobile phone handsets.

  12. Experimental study of the breakdown phase in coaxial plasma guns

    International Nuclear Information System (INIS)

    The problem of the dielectric breakdown of gases and its relevance in plasma devices is discussed, and preliminary results of an experimental study upon the spatial location and time evolution of the breakdown phase in a plasma focus device are given

  13. MODEL METHODS FOR THE ANALYSIS OF MESOCOSM EXPERIMENTAL STUDIES

    NARCIS (Netherlands)

    BRINKMAN, AG; PHILIPPART, CJM; ZUUR, AF

    1995-01-01

    The response of experimental ecosystem dynamics to varying nutrient loads was studied by analysing oxygen time-series. Time-series had been continuously recorded, and the data were analysed on a daily basis using a computer model which describes basic oxygen processes. The resulting sets of producti

  14. Experimental Study on a Rotor for WEPTOS Wave Energy Converter

    DEFF Research Database (Denmark)

    Pecher, Arthur; Kofoed, Jens Peter; Marchalot, Tanguy

    This report presents the results of an experimental study of the power conversion capabilities of one single rotor of the WEPTOS wave energy converter. The investigation focuses mainly on defining the optimal weight distribution in the rotor in order to improve the hydraulic performance through...

  15. Mono, bi- and trinuclear metal complexes derived from new benzene-1,4-bis(3-pyridin-2-ylurea) ligand. Spectral, magnetic, thermal and 3D molecular modeling studies

    Science.gov (United States)

    El-ghamry, Mosad A.; Saleh, Akila A.; Khalil, Saied M. E.; Mohammed, Amira A.

    2013-06-01

    New bis (pyridylurea) ligand, H2L, was synthesized by the reaction of ethylpyridine-2-carbamate (EPC) and p-phenylenediamine. The ligand was characterized by elemental analysis, IR, 1H NMR, electronic and mass spectra. Reaction of the prepared ligand with Co2+, Ni2+, Cu2+, Fe3+, VO2+ and UO22+ ions afforded mono, bi- and trinuclear metal complexes. Also, new mixed ligand complexes of the ligand H2L and 8-hydroxyquinoline (8-HQ) with Co2+, Ni2+, Cu2+ and Fe3+ ions were synthesized. The ligand behaves as bi- and tetradentate toward the transition metal ions, coordination via the pyridine sbnd N, the carbonyl sbnd O and/or the amidic sbnd N atoms in a non, mono- and bis-deprotonated form. The complexes were characterized by elemental and thermal analyses, IR, electronic and mass spectra as well as conductance and magnetic susceptibility measurements. The results showed that the metal complexes exhibited different geometrical arrangements such as square planar, tetrahedral, octahedral and square pyramidal arrangements. The Coats-Redfern equation was used to calculate the kinetic and thermodynamic parameters for the different thermal decomposition steps of some complexes. 3D molecular modeling of the ligand, H2L and a representative complex were studied.

  16. Glucagon in intravenous cholangiography - an experimental study on dogs

    International Nuclear Information System (INIS)

    The present study reports on the effect of glucagon on the excretion of ioglycamate in experimental intravenous cholangiography on dogs. Glucagon increased the bile flow rate highly significantly (p < 0.001). At the same time the concentration of the contrast medium decreased highly significantly (p < 0.001). The biliary tree output of the contrast medium also increased, this increase was not statistically significant. This investigation suggests that glucagon seems to have effect on the bile flow as well as on the output of contrast medium in experimental cholangiography. (orig.)

  17. Theoretical and Experimental Study of Time Reversal in Cubic Crystals

    Institute of Scientific and Technical Information of China (English)

    陆铭慧; 张碧星; 汪承灏

    2004-01-01

    The self-adaptive focusing of the time reversal in anisotropic media is studied theoretically and experimentally. It is conducted for the compressional wave field in the cubic crystal silicon. The experimental result is in agreement with our theoretical analysis. The focusing gain and the displacement distributions of the time reversal field are analysed in detail. It is shown that the waves from different elements of the transducer array arrive at the original place of the source simultaneously after the time reversal operation. The waveform distortions caused by the velocity anisotropy can automatically be compensated for after the time reversal processing.

  18. Simultaneous removal of formaldehyde and benzene in indoor air with a combination of sorption- and decomposition-type air filters.

    Science.gov (United States)

    Sekine, Yoshika; Fukuda, Mitsuru; Takao, Yosuke; Ozano, Takahiro; Sakuramoto, Hikaru; Wang, Kuan Wei

    2011-12-01

    Urgent measures for indoor air pollution caused by volatile organic compounds are required in urban areas of China. Considering indoor air concentration levels and hazardous properties, formaldehyde and benzene should be given priority for pollution control in China. The authors proposed the use of air-cleaning devices, including stand-alone room air cleaners and in-duct devices. This study aimed to find the best combination of sorption and decomposition filters for the simultaneous removal of formaldehyde and benzene, employing four types of air filter units: an activated charcoal filter (ACF), an ACF impregnated with a trapping agent for acidic gases (ACID), a MnO2 filter (MDF) for oxidative decomposition of formaldehyde at room temperature and a photocatalyst filter (PHOTO) coupled with a parallel beam ultraviolet (UV) irradiation device. The performance of the combined systems under air flow rates of 35-165 m3 h(-1) was evaluated in a test chamber (2 m3) with a constant gas generation system. The experimental results and data analysis using a kinetic approach showed the combined system of ACF, PHOTO and MDF significantly reduced both concentrations of formaldehyde and benzene in air without any unpleasant odours caused by the UV-induced photocatalytic reaction. The system was then evaluated in a full-size laboratory (22 m3). This test proved the practical performance of the system even at full scale, and also suggested that the filters should be arranged in the order of PHOTO/ACF/MDF from upstream to downstream. The proposed system has the potential of being used for improving indoor air quality of houses and buildings in China. PMID:22439587

  19. An experimental and numerical study of water jet cleaning process

    CERN Document Server

    Guha, Anirban; Balachandar, Ram

    2010-01-01

    In this paper, we have experimentally, numerically and theoretically investigated the water jet cleaning process. Very high speed water jets (~80-200 m/s) are used in such cleaning operations. These jets diffuse in the surrounding atmosphere by the process of air entrainment and this contributes to the spreading of the jet and subsequent decay of pressure. Estimation of this pressure decay and subsequent placement of the cleaning object is of paramount importance in manufacturing and material processing industries. Also, the pressure distribution on the cleaning surface needs to be assessed in order to understand and optimize the material removal process. Experimental study is performed to understand the pressure characteristics. A Semi-empirical model for capturing the air entrainment has been added to the commercial CFD package FLUENT. The simulation results are validated against ours as well as previous experimental findings. The numerical results have shown that the optimal stand-off distance in cleaning ...

  20. Mechanical properties of jennite: A theoretical and experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Juhyuk, E-mail: juhyuk.moon@stonybrook.edu [Civil Engineering Program, Department of Mechanical Engineering, Stony Brook University, NY 11794 (United States); Yoon, Seyoon [School of Engineering, Kings College, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom); Monteiro, Paulo J.M. [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)

    2015-05-15

    The objective of this study is to determine the mechanical properties of jennite. To date, several hypotheses have been proposed to predict the structural properties of jennite. For the first time as reported herein, the isothermal bulk modulus of jennite was measured experimentally. Synchrotron-based high-pressure x-ray diffraction experiments were performed to observe the variation of lattice parameters under pressure. First-principles calculations were applied to compare with the experimental results and predict additional structural properties. Accurately measured isothermal bulk modulus herein (K{sub 0} = 64(2) GPa) and the statistical assessment on experimental and theoretical results suggest reliable mechanical properties of shear and Young's modulus, Poisson's ratio, and elastic tensor coefficients. Determination of these fundamental structural properties is the first step toward greater understanding of calcium–silicate–hydrate, as well as provides a sound foundation for forthcoming atomic level simulations.

  1. Experimental and numerical study on condensation in transonic steam flow

    Science.gov (United States)

    Majkut, Mirosław; Dykas, Sławomir; Strozik, Michał; Smołka, Krystian

    2015-09-01

    The present paper describes an experimental and numerical study of steam condensing flow in a linear cascade of turbine stator blades. The experimental research was performed on the facility of a small scale steam power plant located at Silesian University of Technology in Gliwice, Poland. The test rig of the facility allows us to perform the tests of steam transonic flows for the conditions corresponding to these which prevail in the low-pressure (LP) condensing steam turbine stages. The experimental data of steam condensing flow through the blade-to- blade stator channel were compared with numerical results obtained using the in-house CFD numerical code TraCoFlow. Obtained results confirmed a good quality of the performed experiment and numerical calculations.

  2. Mechanical properties of jennite: A theoretical and experimental study

    International Nuclear Information System (INIS)

    The objective of this study is to determine the mechanical properties of jennite. To date, several hypotheses have been proposed to predict the structural properties of jennite. For the first time as reported herein, the isothermal bulk modulus of jennite was measured experimentally. Synchrotron-based high-pressure x-ray diffraction experiments were performed to observe the variation of lattice parameters under pressure. First-principles calculations were applied to compare with the experimental results and predict additional structural properties. Accurately measured isothermal bulk modulus herein (K0 = 64(2) GPa) and the statistical assessment on experimental and theoretical results suggest reliable mechanical properties of shear and Young's modulus, Poisson's ratio, and elastic tensor coefficients. Determination of these fundamental structural properties is the first step toward greater understanding of calcium–silicate–hydrate, as well as provides a sound foundation for forthcoming atomic level simulations

  3. Experimental models used for the study of antihepatotoxic agents

    Institute of Scientific and Technical Information of China (English)

    Feroz Ahmad; Nahida Tabassum

    2012-01-01

    Both in vitro and in vivo liver models have been developed in the past years to study the hepatoprotective agents. These systems measure the ability of the test drug to prevent or cure liver toxicity (induced by various hepatotoxins) in experimental animals. In in vitro models fresh hepatocytes are treated with hepatotoxin and the effect of the test drug on the same is evaluated. In in vivo models, a toxic dose or repeated doses of a known hepatotoxin are administered to induce liver damage in experimental animals. The test substance is administered along with, prior to and/or after the toxin treatment. Various chemical agents normally used to induce hepatotoxicty in experimental animals for the evaluation of hepatoprotective agents include carbon tetrachloride, paracetamol, Acrylamide, adriamycin, alcohol, antitubercular drugs etc. The present article explains the mechanism of action of various hepatotoxic chemical/drugs, their dosage and route of administration.

  4. STUDY OF CNS EFFECTS OF MACROLIDE ANTIBIOTICS: AN EXPERIMENTAL STUDY

    Directory of Open Access Journals (Sweden)

    Deshmukh

    2013-02-01

    Full Text Available ABSTRACT: Macrolides are an old, well established class of an tibacterial agents which play an important role in the management of infectious dise ases. The present study was undertaken to study the CNS effects of some of the macrolides ant ibiotics namely erythromycin, clarithromycin, azithromycin and roxithromycin in r ats. 30 healthy adult albino rats of either sex of Haffkine’s strain weighing 100-200g were use d for the study. Each group consists of six animals. Various tests were used for screening of drugs on CNS activity. Amongst the macrolides namely erythromycin claritromycin, azith romycin and roxithromycin, only roxithromycin showed CNS depressant activity in rat s. Similarly only roxithromycin and azithromycin showed anti-inflammatory property.

  5. Maternal Exposure to Ambient Levels of Benzene and Neural Tube Defects among Offspring: Texas, 1999–2004

    OpenAIRE

    Lupo, Philip J.; Symanski, Elaine; Waller, D. Kim; Chan, Wenyaw; Langlois, Peter H; Canfield, Mark A.; Mitchell, Laura E

    2010-01-01

    Background Previous studies have reported positive associations between maternal exposure to air pollutants and several adverse birth outcomes. However, there have been no studies assessing the association between environmental levels of hazardous air pollutants, such as benzene, and neural tube defects (NTDs), a common and serious group of congenital malformations. Objective Our goal was to conduct a case–control study assessing the association between ambient air levels of benzene, toluene,...

  6. Experimental study of curved guide tubes for pellet injection

    International Nuclear Information System (INIS)

    The use of curved guide tubes for transporting frozen hydrogen pellets offers great flexibility for pellet injection into plasma devices. While this technique has been previously employed, an increased interest in its applicability has been generated with the recent ASDEX Upgrade experimental data for magnetic high-field side (HFS) pellet injection. In these innovative experiments, the pellet penetration appeared to be significantly deeper than for the standard magnetic low-field side injection scheme, along with corresponding greater fueling efficiencies. Thus, some of the major experimental fusion devices are planning experiments with HFS pellet injection. Because of the complex geometries of experimental fusion devices, installations with multiple curved guide tube sections will be required for HFS pellet injection. To more thoroughly understand and document the capability of curved guide tubes, an experimental study is under way at the Oak Ridge National Laboratory (ORNL). In particular, configurations and pellet parameters applicable for the DIII-D tokamak and the International Thermonuclear Experimental Reactor (ITER) were simulated in laboratory experiments. Initial test results with nominal 2.7- and 10-mm-diam deuterium pellets are presented and discussed

  7. Lack of correlation between environmental or biological indicators of benzene exposure at parts per billion levels and micronuclei induction

    International Nuclear Information System (INIS)

    Despite growing concern for possible carcinogenic effects associated with environmental benzene exposure in the general population, few studies exist at parts per billion (ppb) levels. We investigated the existence of a relationship between airborne/biological measurements of benzene exposure i.e., personal/area sampling and unmodified urinary benzene/trans,trans-muconic acid; t,t-MA) and micronuclei induction cytochalasin B technique) among exposed chemical laboratory workers (n=47) and traffic wardens (n=15). Although urinary t,t-MA (106.9±123.17 μg/Lurine) correlated (R2=0.37) with urinary benzene (0.66±0.99 μg/Lurine), neither biological measurement correlated with environmental benzene exposure (14.04±9.71 μg/m3; 4.39±3.03 ppb), suggesting that, at ppb level (1 ppb=3.2 μg/m3), airborne benzene constitutes a fraction of the total intake. Traffic wardens and laboratory workers had comparable numbers of micronuclei (4.70±2.63 versus .76±3.11; n.s.), similar to levels recorded in the general population. With univariate/multivariate analysis, no association was found between micronuclei induction and air/urinary benzene exposure variables. Notably, among the personal characteristics examined (including age, gender, smoking, drinking, etc.), high body mass index correlated with micronuclei induction while, among females, use of hormonal medication was associated with less micronuclei. Thus the present study provides no evidence that ppb levels of environmental benzene exposure appreciably affect micronuclei incidence against the background of other relevant factors). However, this should not be taken as an argument against efforts aiming to reduce environmental benzene pollution

  8. Effect of Operating Conditions on CSTR performance: an Experimental Study

    OpenAIRE

    Mohd. Danish; Mohammed K. Al Mesfer

    2015-01-01

    In this work, Saponification reaction of ethyl acetate by sodium hydroxide is studied experimentally in a continuous stirred tank reactor at 1 atmospheric pressure. The aim of this study is to investigate the influence of operating conditions on the conversion and specific rate constant. The parameters considered for analysis are temperature, feed flow rate, residence time, volume of reactor and stirrer rate. The steady state conversion of 0.45 achieved after a period of 30 minute...

  9. Design study of blanket structure for tokamak experimental fusion reactor

    International Nuclear Information System (INIS)

    Design study of the blanket structure for JAERI Experimental Fusion Reactor (JXFR) has been carried out. Studied here were fabrication and testing of the blanket structure (blanket cells, blanket rings, piping and blanket modules), assembly and disassembly of the blanket module, and monitering and testing technique. Problems in design and fabrication of the blanket structure could be revealed. Research and development problems for the future were also disclosed. (author)

  10. An Experimental Study on Hypothyroid Using Rotation Forest

    OpenAIRE

    Sheetal Gaikwad; Nitin Pise

    2014-01-01

    This paper majorly focuses on hypothyroid medical diseases caused by underactive thyroid glands. The dataset used for the study on hypothyroid is taken from UCI repository. Classification of this thyroid disease is a considerable task. An experimental study is carried out using rotation forest using features selection methods to achieve better accuracy. An important step to gain good accuracy is a pre- processing step, thus here two feature selection techniques are used. A filter method, Corr...

  11. Experimental and Analytical Studies of Solar System Chemistry

    Science.gov (United States)

    Burnett, Donald S.

    2003-01-01

    The cosmochemistry research funded by this grant resulted in the publications given in the attached Publication List. The research focused in three areas: (1) Experimental studies of trace element partitioning. (2) Studies of the minor element chemistry and O isotopic compositions of MgAlO4 spinels from Ca-Al-Rich Inclusions in carbonaceous chondrite meteorites, and (3) The abundances and chemical fractionations of Th and U in chondritic meteorites.

  12. Design and experimental studies of a novel circularly polarized antenna

    OpenAIRE

    Zhang Hai; Zhang Wei Guo; Ge Yue He

    2016-01-01

    A circularly polarized antenna with patches on the top is studied in this paper. The antenna is composed of two printed dipoles and four radiation patches which are loaded on top of the dipoles. The antenna is fed by microstrip balum in the middle of dielectric slab. And the balum is connected to a Wilkinson power divider which owns 90 degree phase shift. Numerical simulations of proposed antenna are performed using the 3D electromagnetic simulation software HFSS. The experimental studies of ...

  13. Experimental Studies of Cold Roll Bonded Aluminum Alloys

    OpenAIRE

    Lauvdal, Steinar

    2011-01-01

    This master’s thesis is based on experimental studies of the parameters influencing cold roll bonding (CRB) of the aluminum alloys AA1200 and AA3103,in the work hardened and annealed condition. The effect on the bond strength from the preparations parameters as degreasing agent, scratch brushing and exposure time for oxide growth is investigated in comparison to former studies. Further the effect of rolling speed and effect from contributing factors from the different testing methods is ...

  14. Vortex formation behind movable leaflet: experimental and numerical studies

    OpenAIRE

    Vukicevic, Marija

    2011-01-01

    Fluid structure interaction (FSI) is one of fundamental phenomena encountered everywhere in nature or in industrial systems as well as one of the most studied and the most challenging topics in the fluid mechanics. Its research presents the core objective of this dissertation, along with experimental study of artificial heart devices. Better understanding of FSI could turn the still unexploited phenomenon into a powerful tool for resolving wealthy of multi-physics problems. Recently computati...

  15. A Combined Molecular Dynamics and Experimental Study of Doped Polypyrrole

    OpenAIRE

    Fonner, John M.; Schmidt, Christine E; Ren, Pengyu

    2010-01-01

    Polypyrrole (PPy) is a biocompatible, electrically conductive polymer that has great potential for battery, sensor, and neural implant applications. Its amorphous structure and insolubility, however, limit the experimental techniques available to study its structure and properties at the atomic level. Previous theoretical studies of PPy in bulk are also scarce. Using ab initio calculations, we have constructed a molecular mechanics force field of chloride-doped PPy (PPyCl) and undoped PPy. Th...

  16. Benzene activation and H/D isotope effects in reactions of size selected iron, cobalt and nickel cluster ions

    International Nuclear Information System (INIS)

    A Penning ion trap served to investigate the reaction of size selected transition metal cluster ions in the size range 3< n<30 with benzene and benzene-d6 under single collision conditions. We performed kinetic studies by Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) mass spectrometry on anionic and cationic iron, cobalt and nickel clusters. Kinetic Isotope Effects KIE(n) in total reaction rates are inverse, Dehydrogenation Isotope Effects DIE(n) are predominantly normal. A multistep model of adsorption and stepwise dehydrogenation from the precursor adsorbate proves suitable to rationalize the found KIEs and DIEs in principle.

  17. Benzene activation and H/D isotope effects in reactions of size selected iron, cobalt and nickel cluster ions

    Energy Technology Data Exchange (ETDEWEB)

    Merkert, Christine; Mohrbach, Jennifer; Tombers, Matthias; Barzen, Lars; Gaffga, Maximilian; Niedner-Schatteburg, Gereon [Fachbereich Chemie and Forschungszentrum OPTIMAS, Technische Universitaet Kaiserslautern, 67663 Kaiserslautern (Germany)

    2013-07-01

    A Penning ion trap served to investigate the reaction of size selected transition metal cluster ions in the size range 3benzene and benzene-d6 under single collision conditions. We performed kinetic studies by Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) mass spectrometry on anionic and cationic iron, cobalt and nickel clusters. Kinetic Isotope Effects KIE(n) in total reaction rates are inverse, Dehydrogenation Isotope Effects DIE(n) are predominantly normal. A multistep model of adsorption and stepwise dehydrogenation from the precursor adsorbate proves suitable to rationalize the found KIEs and DIEs in principle.

  18. Benzene-induced genotoxicity in mice in vivo detected by the alkaline comet assay

    DEFF Research Database (Denmark)

    Tuo, J; Loft, S; Thomsen, M S;

    1996-01-01

    The myelotoxic and genotoxic effects of benzene have been related to oxidative DNA damage after metabolism by CYP2E1. Single cell gel electrophoresis (alkaline comet assay) detects DNA damage and may thus be a convenient method for the study of benzene genotoxicity. Benzene exposure to NMRI mice as...... a single oral gavage at 40, 200 or 450 mg/kg resulted in dose-related DNA damage indicated by an increased comet tail length of peripheral blood lymphocytes and bone marrow nucleated cells sampled 6 h after exposure. After a dose of 40 mg/kg, there was a 1.6-fold increase of 'tail length' in bone...... types (p < 0.01). By comparing our data with those from genotoxicity studies on benzene using other methods, we conclude that the 'alkaline comet assay' is a sensitive method to detect DNA damage induced by benzene. We also infer that CYP2E1 contributes, at least partly, to the formation of the 'comet...

  19. Measurement of Benzene in Air by Iranian Single-Wall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Athena Rafieepour

    2012-01-01

    Full Text Available Background: Nanotechnology is a new approach that has been lionized in recentyears. One of its applications is its consumption as an absorbent. In this study, thesingle-wall carbon nanotubes (SWCNTs were used as an absorbent for samplingbenzene in the air.Materials and Methods: For this study, SWCNTs manufactured by Iran and SKC’sactivated charcoal were used for sampling benzene vapors. Preparation and analysis ofthe samples were done by carbon disulfide and GC-FID (gas chromatography-flameionization detector, respectivelyResults: The results indicated that the performance of SWCNTs is less thanconventional activated charcoal for sampling benzene vapors in the airConclusion: The findings of this study showed that the performance of SWCNTs inthe sampling of benzene vapors in the air is very poor and, therefore, cannot be a goodalternative to SKC’s activated charcoal.

  20. Highly selective ethylbenzene production through alkylation of dilute ethylene with gas phase-liquid phase benzene and transalkylation feed

    Institute of Scientific and Technical Information of China (English)

    Shenglin Liu; Fucun Chen; Sujuan Xie; Peng Zeng; Xiyan Du; Longya Xu

    2009-01-01

    A novel industrial process was designed for the highly selective production of ethylbenzene.It comprised of a reactor vessel,vapor phase ethylene feed stream,benzene and transalkylation feed stream.Especially the product stream containing ethylbenzene was used to heat the reactor vessel,which consisted of an alkylation section,an upper heat exchange section,and a bottom heat exchange section.In such a novel reactor,vapor phase benzene and liquid phase benzene were coexisted due to the heat produced by isothermal reaction between the upper heat exchange section and the bottom heat exchange section.The process was demonstrated by the thermodynamic analysis and experimental results.In fact,during the 1010 hour-life-test of gas phase ethene with gas phase-liquid phase benzene alkylation reaction,the ethene conversion was above 95%,and the ethylbenzene selectivity was above 83% (only benzene feed) and even higher than 99% (benzene plus transalkylation feed).At the same time,the xylene content in the ethylbenzene was less than 100 ppm when the reaction was carried out under the reaction conditions of 140-185℃ of temperature,1.6-2.1 MPa of pressure,3.0-5.5 of benzene/ethylene mole ratio,4-6 v% of transalkylation feed/(benzene+transalkylation feed),0.19-0.27 h-1 of ethene space velocity,and 1000 g of 3998 catalyst loaded.Thus,compared with the conventional ethylbenzene synthesis route,the transalkylation reactor could be omitted in this novel Industrial process.

  1. Experimental and Theoretical Study on Pyrolysis of Isopsoralen

    Institute of Scientific and Technical Information of China (English)

    Jiu-zhong Yang; Feng Zhang; Liang-yuan Jia; Li-dong Zhang; Fei Qi; Hai-yan Fan; Ji-bao Cai

    2012-01-01

    The pyrolysis of isopsoralen was studied by synchrotron vacuum ultraviolet photoionization mass spectrometry at low pressure.The pyrolysis products were detected at different photon energies,the ratios of products to precursor were measured at various pyrolysis temperatures.The experimental results demonstrate that the main pyrolysis products are primary CO and sequential CO elimination products (C10H6O2 and C9H6O).The decomposition channels of isopsoralen were also studied by the density functional theory,then rate constants for competing pathways were calculated by the transition state theory.The dominant decomposition channels of isopsoralen and the molecular structures for corresponding products were identified bv combined experimental and theoretical studies.

  2. Experimental Studies of the Transport Parameters of Warm Dense Matter

    Energy Technology Data Exchange (ETDEWEB)

    Chouffani, Khalid [Idaho State Univ., Pocatello, ID (United States)

    2014-12-01

    There is a need to establish fundamental properties of matter and energy under extreme physical conditions. Although high energy density physics (HEDP) research spans a wide range of plasma conditions, there is one unifying regime that is of particular importance and complexity: that of warm dense matter, the transitional state between solid state condensed matter and energetic plasmas. Most laboratory experimental conditions, including inertial confinement implosion, fall into this regime. Because all aspects of laboratory-created high-energy-density plasmas transition through the warm dense matter regime, understanding the fundamental properties to determine how matter and energy interact in this regime is an important aspect of major research efforts in HEDP. Improved understanding of warm dense matter would have significant and wide-ranging impact on HEDP science, from helping to explain wire initiation studies on the Sandia Z machine to increasing the predictive power of inertial confinement fusion modeling. The central goal or objective of our proposed research is to experimentally determine the electrical resistivity, temperature, density, and average ionization state of a variety of materials in the warm dense matter regime, without the use of theoretical calculations. Since the lack of an accurate energy of state (EOS) model is primarily due to the lack of experimental data, we propose an experimental study of the transport coefficients of warm dense matter.

  3. A statistical study of the correlation between k` or log k` and log P{sub OW} for a group of benzene and naphthalene derivatives in micellar liquid chromatography using a C-18 column

    Energy Technology Data Exchange (ETDEWEB)

    Marina, M.L. [Dept. de Quimica Analitica, Facultad de Ciencias, Univ. de Alcala de Henares (Spain); Garcia, M.A. [Dept. de Quimica Analitica, Facultad de Ciencias, Univ. de Alcala de Henares (Spain); Pastor, M. [Dept. de Quimica Organica, Facultad de Farmacia, Univ. de Alcala de Henares (Spain); Vera, S. [Dept. de Quimica Analitica, Facultad de Ciencias, Univ. de Alcala de Henares (Spain)

    1995-02-01

    It is shown that the logarithm of the capacity factor (log k`) for fifteen benzene and naphthalene derivatives in micellar liquid chromatogrphy with forty nine different mobile phases generally correlates better with the logarithm of the octanol-water partition coefficient (log P{sub ow}) than the capacity factor (k`). Optimum conditions are established to obtain the best linear correlations of log k`-log P{sub ow}. (orig.)

  4. Test of electron beam technology on Savannah River Laboratory low-activity aqueous waste for destruction of benzene, benzene derivatives, and bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Dougal, R.A. [Univ. of South Carolina, Columbia, SC (United States). Dept. of Electrical and Computer Engineering

    1993-08-01

    High energy radiation was studied as a means for destroying hazardous organic chemical wastes. Tests were conducted at bench scale with a {sup 60}Co source, and at full scale (387 l/min) with a 1.5 MV electron beam source. Bench scale tests for both benzene and phenol included 32 permutations of water quality factors. For some water qualities, as much as 99.99% of benzene or 90% of phenol were removed by 775 krads of {sup 60}Co irradiation. Full scale testing for destruction of benzene in a simulated waste-water mix showed loss of 97% of benzene following an 800 krad dose and 88% following a 500 krad dose. At these loss rates, approximately 5 Mrad of electron beam irradiation is required to reduce concentrations from 100 g/l to drinking water quality (5 {mu}g/l). Since many waste streams are also inhabited by bacterial populations which may affect filtering operations, the effect of irradiation on those populations was also studied. {sup 60}Co and electron beam irradiation were both lethal to the bacteria studied at irradiation levels far lower than were necessary to remove organic contaminants.

  5. Test of electron beam technology on Savannah River Laboratory low-activity aqueous waste for destruction of benzene, benzene derivatives, and bacteria

    International Nuclear Information System (INIS)

    High energy radiation was studied as a means for destroying hazardous organic chemical wastes. Tests were conducted at bench scale with a 60Co source, and at full scale (387 l/min) with a 1.5 MV electron beam source. Bench scale tests for both benzene and phenol included 32 permutations of water quality factors. For some water qualities, as much as 99.99% of benzene or 90% of phenol were removed by 775 krads of 60Co irradiation. Full scale testing for destruction of benzene in a simulated waste-water mix showed loss of 97% of benzene following an 800 krad dose and 88% following a 500 krad dose. At these loss rates, approximately 5 Mrad of electron beam irradiation is required to reduce concentrations from 100 g/l to drinking water quality (5 μg/l). Since many waste streams are also inhabited by bacterial populations which may affect filtering operations, the effect of irradiation on those populations was also studied. 60Co and electron beam irradiation were both lethal to the bacteria studied at irradiation levels far lower than were necessary to remove organic contaminants

  6. Modeling Biodegradation Kinetics on Benzene and Toluene and Their Mixture

    Directory of Open Access Journals (Sweden)

    Aparecido N. Módenes

    2007-10-01

    Full Text Available The objective of this work was to model the biodegradation kinetics of toxic compounds toluene and benzene as pure substrates and in a mixture. As a control, Monod and Andrews models were used. To predict substrates interactions, more sophisticated models of inhibition and competition, and SKIP (sum kinetics interactions parameters model were applied. The models evaluation was performed based on the experimental data from Pseudomonas putida F1 activities published in the literature. In parameter identification procedure, the global method of particle swarm optimization (PSO was applied. The simulation results show that the better description of the biodegradation process of pure toxic substrate can be achieved by Andrews' model. The biodegradation process of a mixture of toxic substrates is modeled the best when modified competitive inhibition and SKIP models are used. The developed software can be used as a toolbox of a kinetics model catalogue of industrial wastewater treatment for process design and optimization.

  7. Isolated benzene and dichlorobenzene on the Ge(1 0 0)-c(4 × 2) surface

    International Nuclear Information System (INIS)

    Adsorption of isolated benzene and dichlorobenzene molecules on the Ge(1 0 0) surface is studied based on total energy and electronic structure density functional theory calculations. It is found that the most stable configuration for benzene on Ge(1 0 0) is the symmetric on-top single dimer bonding structure, with the asymmetric tight bridge configuration being the second lowest energy geometry. This is in contrast to benzene on Si(1 0 0) where the asymmetric tight bridge structure is the most stable structure. For dichlorobenzene on Ge(1 0 0) it is found that the on-top single dimer bonding structure is the most stable. We also show that while the stability of the adsorbed dichlorobenzene is significantly enhanced with respect to the adsorbed benzene on Ge(1 0 0), presumably due to the presence of the chlorine atoms, its electronic structure is similar to that in the gas phase. The latter was found to be similar to the weakly interacting benzene molecule with Ge(1 0 0).

  8. Thermal behaviors and grafting process of LDH/benzene derivative hybrid systems

    International Nuclear Information System (INIS)

    Highlights: ► Orientation of the organic entities between the layers of the mineral network. ► Influence of the organics functional group on the stability of the hybrid material. ► Demonstration of three different behaviors in terms of the grafting process. - Abstract: Thermal behaviors of four hybrid layered double hydroxide (LDH) phases have been studied by thermogravimetric analyses coupled with mass spectroscopy, temperature dependence of X-ray powder diffraction measurements, and temperature dependence of infrared spectroscopy measurements. Inorganic zinc–aluminium LDH main layers (with a Zn2+/Al3+ cationic ratio of 2) inserted the following four organic anions: benzene carboxylate, 4-hydroxy-benzene carboxylate, benzene sulfonate and 4-hydroxy-benzene sulfonate. The four LDH hybrids have been synthesized by the coprecipitation method. The as-prepared samples have been characterized and their compositions were determined. Thermal evolution of the crystalline phases during the dehydration (occurring before 200 °C) and the dehydroxylation (occurring between 200 and 300 °C) gave evidence for organic anion grafting onto the inorganic main layer. The thermal stability of the LDH hybrid system depends on the nature of the intercalated aromatic anion. The thermal grafting process can be monitored, as well as its thermal reversibility, by choosing the functionalizations of the benzenic anion and the temperature of the applied heat treatment.

  9. THE INFLUENCE OF BENZENE AS A TRACE REACTANT IN TITAN AEROSOL ANALOGS

    International Nuclear Information System (INIS)

    Benzene has been detected in Titan's atmosphere by Cassini instruments, with concentrations ranging from sub-ppb in the stratosphere to ppm in the ionosphere. Sustained levels of benzene in the haze formation region could signify that it is an important reactant in the formation of Titan's organic aerosol. To date, there have not been laboratory investigations to assess the influence of benzene on aerosol properties. We report a laboratory study on the chemical composition of organic aerosol formed from C6H6/CH4/N2 via far ultraviolet irradiation (120-200 nm). The compositional results are compared to those from aerosol generated by a more ''traditional Titan'' mixture of CH4/N2. Our results show that even a trace amount of C6H6 (10 ppm) has significant impact on the chemical composition and production rates of organic aerosol. There are several pathways by which photolyzed benzene may react to form larger molecules, both with and without the presence of CH4, but many of these reaction mechanisms are only beginning to be explored for the conditions at Titan. Continued work investigating the influence of benzene in aerosol growth will advance understanding of this previously unstudied reaction system.

  10. Incense, sparklers and cigarettes are significant contributors to indoor benzene and particle levels

    Directory of Open Access Journals (Sweden)

    Werner Tirler

    2015-03-01

    Full Text Available Introduction. The increased use of incense, magic candles and other flameless products often produces indoor pollutants that may represent a health risk for humans. Today, in fact, incense and air fresheners are used inside homes as well as in public places including stores, shopping malls and places of worship. As a source of indoor contamination, the impact of smoke, incense and sparklers on human health cannot be ignored. Aim. In the present work, we report the results of an emission study regarding particles (PM10 and particle number concentration, PNC and benzene, produced by various incense sticks and sparklers. Results and discussion.The results obtained for benzene, PM10 and PNC, showed a strong negative influence on air quality when these products were used indoors. Various incense sticks gave completely different benzene results: from a small increase of the benzene concentration in the air, just slightly above the background levels of ambient air, to very high concentrations, of more than 200 µg/m³ of benzene in the test room after the incense sticks had been tested.

  11. THE INFLUENCE OF BENZENE AS A TRACE REACTANT IN TITAN AEROSOL ANALOGS

    Energy Technology Data Exchange (ETDEWEB)

    Trainer, Melissa G. [Planetary Environments Laboratory, Code 699, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Sebree, Joshua A. [NASA Postdoctoral Program Fellow, Code 699, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Heidi Yoon, Y.; Tolbert, Margaret A., E-mail: melissa.trainer@nasa.gov [Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Box 216 UCB, Boulder, CO 80309 (United States)

    2013-03-20

    Benzene has been detected in Titan's atmosphere by Cassini instruments, with concentrations ranging from sub-ppb in the stratosphere to ppm in the ionosphere. Sustained levels of benzene in the haze formation region could signify that it is an important reactant in the formation of Titan's organic aerosol. To date, there have not been laboratory investigations to assess the influence of benzene on aerosol properties. We report a laboratory study on the chemical composition of organic aerosol formed from C{sub 6}H{sub 6}/CH{sub 4}/N{sub 2} via far ultraviolet irradiation (120-200 nm). The compositional results are compared to those from aerosol generated by a more ''traditional Titan'' mixture of CH{sub 4}/N{sub 2}. Our results show that even a trace amount of C{sub 6}H{sub 6} (10 ppm) has significant impact on the chemical composition and production rates of organic aerosol. There are several pathways by which photolyzed benzene may react to form larger molecules, both with and without the presence of CH{sub 4}, but many of these reaction mechanisms are only beginning to be explored for the conditions at Titan. Continued work investigating the influence of benzene in aerosol growth will advance understanding of this previously unstudied reaction system.

  12. Low-energy structures of benzene clusters with a novel accurate potential surface.

    Science.gov (United States)

    Bartolomei, M; Pirani, F; Marques, J M C

    2015-12-01

    The benzene-benzene (Bz-Bz) interaction is present in several chemical systems and it is known to be crucial in understanding the specificity of important biological phenomena. In this work, we propose a novel Bz-Bz analytical potential energy surface which is fine-tuned on accurate ab initio calculations in order to improve its reliability. Once the Bz-Bz interaction is modeled, an analytical function for the energy of the Bzn clusters may be obtained by summing up over all pair potentials. We apply an evolutionary algorithm (EA) to discover the lowest-energy structures of Bzn clusters (for n=2-25), and the results are compared with previous global optimization studies where different potential functions were employed. Besides the global minimum, the EA also gives the structures of other low-lying isomers ranked by the corresponding energy. Additional ab initio calculations are carried out for the low-lying isomers of Bz3 and Bz4 clusters, and the global minimum is confirmed as the most stable structure for both sizes. Finally, a detailed analysis of the low-energy isomers of the n = 13 and 19 magic-number clusters is performed. The two lowest-energy Bz13 isomers show S6 and C3 symmetry, respectively, which is compatible with the experimental results available in the literature. The Bz19 structures reported here are all non-symmetric, showing two central Bz molecules surrounded by 12 nearest-neighbor monomers in the case of the five lowest-energy structures. PMID:26422699

  13. Annoyance Caused by Noise and Air Pollution during Pregnancy: Associated Factors and Correlation with Outdoor NO2 and Benzene Estimations.

    OpenAIRE

    Ana Fernández-Somoano; Sabrina Llop; Inmaculada Aguilera; Ibon Tamayo-Uria; María Dolores Martínez; Maria Foraster; Ferran Ballester; Adonina Tardón

    2015-01-01

    This study aimed to describe the degree of annoyance among pregnant women in a Spanish cohort and to examine associations with proximity to traffic, NO2 and benzene exposure. We included 2457 participants from the Spanish Childhood and Environment study. Individual exposures to outdoor NO2 and benzene were estimated, temporally adjusted for pregnancy. Interviews about sociodemographic variables, noise and air pollution were carried out. Levels of annoyance were assessed using a scale from 0 (...

  14. Experimental and theoretical studies of highly emissive dinuclear Cu(I) halide complexes with delayed fluorescence.

    Science.gov (United States)

    Kang, Liju; Chen, Jin; Teng, Teng; Chen, Xu-Lin; Yu, Rongmin; Lu, Can-Zhong

    2015-07-01

    A series of luminescent homo-dinuclear Cu(I) halide complexes, [PPh2PAr2Cu(μ-X)2CuPPh2PAr2] (X = I (1), Br (2), Cl (3)) (PPh2PAr2 = (1-bis(2-methylphenyl)phosphino-2-diphenylphosphino)benzene) were synthesized from the reaction of the corresponding cuprous halide and the chelating bisphosphine ligand PPh2PAr2 in CH3CN. The complexes were structurally characterized by X-ray single crystal analysis. Their photophysical properties were studied in detail. The Cu(I) atoms in these complexes are four-coordinated and adopt a tetrahedral coordination geometry. In each complex, the copper centers are bridged by two halide anions and each Cu(I) is chelated further terminally by a PPh2PAr2 ligand. The[Cu(μ-X)2Cu] cores have similar butterfly-type configurations. The distances between the Cu(I) atoms in each complex are over 2.94 Å. In the solid state, these complexes are highly emissive and exhibit bluish-green photoluminescence (emission peaks, λmax = 488 nm (1), 482 nm (2), 490 nm (3)) with short lifetimes (4.9-5.9 μs) and high quantum yields (ϕ = 0.42-0.95) at room temperature. In this series of complexes, the ligand-field strengths of the ions (I(-) complexes indicate that the mechanism of their emissions involves two thermal-equilibrium excited states. At room temperature, the complexes display thermally activated delayed fluorescences with short decay lifetimes. With a decrease of the temperature, a significant increase of emission decay times by almost 2 orders of magnitude is observed. At temperatures below T ≈ 100 K, the decay times of the studied complexes are over one hundred microseconds long, which indicates that the emission originates mainly from the triplet state (T1 state). To interpret the varied temperature photophysics of these complexes, an equilibrated 2 excited states model S0 ← T1 ↔ S1 → S0 was used. The results of the experimental and DFT calculations suggest that the emission in the solid state originates from the (1,3)(MLCT + XLCT

  15. Risk estimation of benzene-induced leukemia by radiation equivalent dose

    International Nuclear Information System (INIS)

    Based on the Hiroshima and Nagasaki epidemiological study, risk assessment system for radiation has been well developed and is practically applied to the international protection standards. Hence, defining the radiation equivalent dose for chemical agents could place in the order of their risk. As well as the radiation, benzene causes leukemia to humans. Therefore, we evaluated the radiation-equivalent dose for benzene based on chromosome aberration rates induced by its metabolites and low-dose rate radiation because chromosome aberration is thought to be closely related to the leukemogenesis. Using radiation risk coefficient, the leukemia risk caused by 1 mg/m3 benzene inhalation was estimated 5.5 - 7.3 x 10-8, which is underestimated compared to other studies based on human epidemiological researches. (author)

  16. The Role of Acid Strength of Modified NaX Zeoliteson Gas Phase Ethylation of Benzene

    Directory of Open Access Journals (Sweden)

    Sanghamitra Barman

    2010-01-01

    Full Text Available The role of acid strength of modified NaX zeolites in gas phase ethylation of benzene were studied over Ce exchanged NaX zeolite of different types. Acidity of the modified zeolite was investigated by means of adsorbing ammonia at different temperature. The conversion of reactantsvaries with the acid strength as well as the different types of the zeolites. The strong acid sites are active centers while the weak acid sites are inactive. The influences of various process parameters such as temperature, space-time and the feed ratio of benzene to ethanol on benzene conversion over most acidic zeolite were studied. The kinetic and adsorption constants of the rate equations were estimated by the best fit. From the estimated kinetic constants, the activation energies and frequency factors for various reactions were determined. The activation energy values compared well with those reported by other investigators for same reactions over similar catalysts.

  17. Experimental study of elementary collection efficiency of aerosols by spray: Design of the experimental device

    Energy Technology Data Exchange (ETDEWEB)

    Ducret, D.; Vendel, J.; Garrec. S.L.

    1995-02-01

    The safety of a nuclear power plant containment building, in which pressure and temperature could increase because of a overheating reactor accident, can be achieved by spraying water drops. The spray reduces the pressure and the temperature levels by condensation of steam on cold water drops. The more stringent thermodynamic conditions are a pressure of 5.10{sup 5} Pa (due to steam emission) and a temperature of 413 K. Moreover its energy dissipation function, the spray leads to the washout of fission product particles emitted in the reactor building atmosphere. The present study includes a large program devoted to the evaluation of realistic washout rates. The aim of this work is to develop experiments in order to determine the collection efficiency of aerosols by a single drop. To do this, the experimental device has to be designed with fundamental criteria:-Thermodynamic conditions have to be representative of post-accident atmosphere. Thermodynamic equilibrium has to be attained between the water drops and the gaseous phase. Thermophoretic, diffusiophoretic and mechanical effects have to be studied independently. Operating conditions have to be homogenous and constant during each experiment. This paper presents the design of the experimental device. In practice, the consequences on the design of each of the criteria given previously and the necessity of being representative of the real conditions will be described.

  18. Experimental Vibration Study on the Healthy and Delaminated Composite Plates

    International Nuclear Information System (INIS)

    Vibration based damage, in particular delamination detection, in the composite structures is an active research area. The present study is also on the dynamics of the composite plates with and without delamination based on the experimental study. The test plate made of E-glass fibre and epoxy resins has been used here. A piezo-electric shaker has been used to excite the composite plate and the acceleration responses were measured using the number of accelerometers. The dynamics of the delaminated composite plates were then compared with a healthy composite plate when the vibration experiments have been conducted at the lower modes. The paper will discuss the observations made on the measured vibration responses from both the healthy and the delaminated plates and the possibility of the delamination detection from the experimental vibration data.

  19. An Experimental Study of a Pulsed Electromagnetic Plasma Accelerator

    Science.gov (United States)

    Thio, Y. C. Francis; Eskridge, Richard; Lee, Mike; Smith, James; Martin, Adam; Markusic, Tom E.; Cassibry, Jason T.; Rodgers, Stephen L. (Technical Monitor)

    2002-01-01

    Experiments are being performed on the NASA Marshall Space Flight Center (MSFC) pulsed electromagnetic plasma accelerator (PEPA-0). Data produced from the experiments provide an opportunity to further understand the plasma dynamics in these thrusters via detailed computational modeling. The detailed and accurate understanding of the plasma dynamics in these devices holds the key towards extending their capabilities in a number of applications, including their applications as high power (greater than 1 MW) thrusters, and their use for producing high-velocity, uniform plasma jets for experimental purposes. For this study, the 2-D MHD modeling code, MACH2, is used to provide detailed interpretation of the experimental data. At the same time, a 0-D physics model of the plasma initial phase is developed to guide our 2-D modeling studies.

  20. Experimental study on self-modulation of ion plasma oscillations

    International Nuclear Information System (INIS)

    Experimental study on the self-modulation of externally amplitude-modulated ion plasma oscillations is described. Oscillations were excited by applying an rf voltage with a frequency near the ion plasma frequency to a grid being a wall of the plasma container. The envelopes of such oscillations were observed to break up into several spikes if their amplitudes were above a value. Individual spikes thus formed were found to have similar properties to those of envelope solitons, although the spikes were observed not to move in the laboratory frame. The number of spikes per group was observed to depend strongly on various parameters. Frequency spectra of excited oscillations were studied over various amplitudes of the applied rf voltage. Comparison of these experimental results with theoretical ones indicates that the self-modulation of oscillations observed here occurs due to the modulational instability. (auth.)