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Sample records for benzene experimental study

  1. Mineral-assisted production of benzene under hydrothermal conditions: Insights from experimental studies on C6 cyclic hydrocarbons

    Science.gov (United States)

    Venturi, Stefania; Tassi, Franco; Gould, Ian R.; Shock, Everett L.; Hartnett, Hilairy E.; Lorance, Edward D.; Bockisch, Christiana; Fecteau, Kristopher M.; Capecchiacci, Francesco; Vaselli, Orlando

    2017-10-01

    Volatile Organic Compounds (VOCs) are ubiquitously present at low but detectable concentrations in hydrothermal fluids from volcanic and geothermal systems. Although their behavior is strictly controlled by physical and chemical parameters, the mechanisms responsible for the production of most VOCs in natural environments are poorly understood. Among them, benzene, whose abundances were found to be relatively high in hydrothermal gases, can theoretically be originated from reversible catalytic reforming processes, i.e. multi-step dehydrogenation reactions, involving saturated hydrocarbons. However, this hypothesis and other hypotheses are difficult to definitively prove on the basis of compositional data obtained by natural gas discharges only. In this study, therefore, laboratory experiments were carried out to investigate the production of benzene from cyclic hydrocarbons at hydrothermal conditions, specifically 300 °C and 85 bar. The results of experiments carried out in the presence of water and selected powdered minerals, suggest that cyclohexane undergoes dehydrogenation to form benzene, with cyclohexene and cyclohexadiene as by-products, and also as likely reaction intermediates. This reaction is slow when carried out in water alone and competes with isomerization and hydration pathways. However, benzene formation was increased compared to these competing reactions in the presence of sulfide (sphalerite and pyrite) and iron oxide (magnetite and hematite) minerals, whereas no enhancement of any reaction products was observed in the presence of quartz. The production of thiols was observed in experiments involving sphalerite and pyrite, suggesting that sulfide minerals may act both to enhance reactivity and also as reactants after dissolution. These experiments demonstrate that benzene can be effectively produced at hydrothermal conditions through dehydrogenation of saturated cyclic organic structures and highlight the crucial role played by minerals in this

  2. Experimental and theoretical study of surface tension of binary mixtures of (n-alkyl acetates + heptane, benzene, and toluene)

    International Nuclear Information System (INIS)

    Rafati, Amir Abbas; Ghasemian, Ensieh

    2009-01-01

    Surface properties of binary mixtures of (n-alkyl acetates + heptane, benzene, and toluene) have been measured by surface tension method at T = 298.15 K and atmospheric pressure. Also, the surface tension has been predicted based on the Suarez method. This method combines a model for the description of surface tension of liquid mixtures with a group contribution method for the calculation of activity coefficient. The mean relative standard deviations obtained from the comparison of experimental (measured) and calculated surface tension values for the eight binary systems are less than 1.5%, which leads to concluding that the model shows a good accuracy in different situations in comparison with other predicted equations. In addition, the relative Gibbs adsorption and the surface mole fraction have been evaluated using this model. The surface tension deviations were calculated from experimental results and have been fitted to the Redlich-Kister type polynomial relation

  3. Molecular and electronic structures of oxo-bis(benzene-1,2-dithiolato)chromate(V) monoanions. A combined experimental and density functional study.

    Science.gov (United States)

    Kapre, Ruta; Ray, Kallol; Sylvestre, Isabelle; Weyhermüller, Thomas; DeBeer George, Serena; Neese, Frank; Wieghardt, Karl

    2006-05-01

    Two oxo-bis(benzene-1,2-dithiolato)chromate(V) complexes, namely, [CrO(L(Bu))2]1- and [CrO(L(Me))2]1-, have been synthesized and studied by UV-vis, EPR, magnetic circular dichroism (MCD), and X-ray absorption spectroscopy and by X-ray crystallography; their electro- and magnetochemistries are reported. H2L(Bu) represents the pro-ligand 3,5-di-tert-butylbenzene-1,2-dithiol, and H2L(Me) is the corresponding 4-methyl-benzene-1,2-dithiol. A structural feature of interest for both the complexes is the folding of the dithiolate ligands about the S-S vector providing Cs symmetry to the complexes. Geometry optimizations using all-electron density functional theory with scalar relativistic corrections at the second-order Douglas-Kroll-Hess (DKH2) and zeroth-order regular approximation (ZORA) levels result in excellent agreement with the experimentally determined structures and electronic and S K-edge X-ray absorption spectra. From DFT calculations, the Cs instead of C2v symmetry for the complexes is attributed to the strong S(3p) --> Cr(3d(x2-y2)) pi-donation in Cs geometry providing additional stability to the complexes.

  4. 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.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Faust, Rudiger [Univ. of California, Berkeley, CA (United States)

    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.

  6. Benzene degradation coupled with chlorate reduction in soil column study

    NARCIS (Netherlands)

    Tan, N.C.G.; Doesburg, van W.C.J.; Langenhoff, A.A.M.; Stams, A.J.M.

    2006-01-01

    Perchlorate and chlorate are electron acceptors that during reduction result in the formation of molecular oxygen. The produced oxygen can be used for activation of anaerobic persistent pollutants, like benzene. In this study chlorate was tested as potential electron acceptor to stimulate benzene

  7. Draft Benzene Case Study Review - Second Prospective Report Study Science Advisory Board Review, March 2008

    Science.gov (United States)

    EPA developed a methodology for estimating the health benefits of benzene reductions and has applied it in a metropolitan-scale case study of the benefits of CAA controls on benzene emissions to accompany the main 812 analysis.

  8. Benzene Case Study Final Report - Second Prospective Report Study Science Advisory Board Review, July 2009

    Science.gov (United States)

    EPA developed a methodology for estimating the health benefits of benzene reductions and has applied it in a metropolitan-scale case study of the benefits of CAA controls on benzene emissions to accompany the main 812 analysis.

  9. (Liquid + liquid) equilibria of (sulfolane + benzene + n-hexane), (N-formylmorpholine + benzene + n-hexane), and (sulfolane + N-formylmorpholine + benzene + n-hexane) at temperatures ranging from (298.15 to 318.15) K: Experimental results and correlation

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoudi, Jafar [School of Chemical, Gas and Petroleum Engineering, Semnan University, Semnan 35195-363 (Iran, Islamic Republic of); Lotfollahi, Mohammad Nader, E-mail: mnlotfollahi@semnan.ac.i [School of Chemical, Gas and Petroleum Engineering, Semnan University, Semnan 35195-363 (Iran, Islamic Republic of)

    2010-04-15

    The experimental (liquid + liquid) equilibrium (LLE) properties for two ternary systems containing (N-formylmorpholine + benzene + n-hexane), (sulfolane + benzene + n-hexane) and a quaternary mixed solvent system (sulfolane + N-formylmorpholine + benzene + n-hexane) were measured at temperature ranging from (298.15 to 318.15) K and at an atmospheric pressure. The experimental distribution coefficients and selectivity factors are presented to evaluate the efficiency of the solvents for extraction of benzene from n-hexane. The LLE results obtained indicate that increasing temperature decreases selectivity for all solvents. The LLE results for the systems studied were used to obtain binary interaction parameters in the UNIQUAC model by minimizing the root mean square deviations (RMSD) between the experimental and calculated results. Using the interaction parameters obtained, the phase equilibria in the systems were calculated and plotted. The calculated compositions based on the UNIQUAC model were found to be in good agreement with the experimental values. The result of the RMSD obtained by comparing the calculated and experimental two-phase compositions is 0.0163 for (N-formylmorpholine + benzene + n-hexane) system and is 0.0120 for (sulfolane + benzene + n-hexane) system.

  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. Interim report: Study of benzene release from Savannah River in-tank precipitation process slurry simulant

    International Nuclear Information System (INIS)

    Rappe, K.G.; Gauglitz, P.A.

    1997-09-01

    At the Savannah River Site, the in-tank precipitation (ITP) process uses sodium tetraphenylborate (NaTPB) to precipitate radioactive cesium from alkaline wastes. During this process, potassium is also precipitated to form a 4-wt% KTPB/CsTPB slurry. Residual NaTPB decomposes to form benzene, which is retained by the waste slurry. The retained benzene is also readily released from the waste during subsequent waste processing. While the release of benzene certainly poses both flammability and toxicological safety concerns, the magnitude of the hazard depends on the rate of release. Currently, the mechanisms controlling the benzene release rates are not well understood, and predictive models for estimating benzene release rates are not available. The overall purpose of this study is to obtain quantitative measurements of benzene release rates from a series of ITP slurry stimulants. This information will become a basis for developing a quantitative mechanistic model of benzene release rates. The transient benzene release rate was measured from the surface of various ITP slurry (solution) samples mixed with benzene. The benzene release rate was determined by continuously purging the headspace of a sealed sample vessel with an inert gas (nitrogen) and analyzing that purged headspace vapor for benzene every 3 minutes. The following 75-mL samples were measured for release rates: KTPB slurry with 15,000 ppm freshly added benzene that was gently mixed with the slurry, KTPB slurry homogenized (energetically mixed) with 15,000 ppm and 5,000 ppm benzene, clear and filtered KTPB salt solution saturated with benzene (with and without a pure benzene layer on top of the solution), and a slurry sample from a large demonstration experiment (DEMO slurry) containing-benzene generated in situ

  12. Study of benzene release from Savannah River in-tank precipitation process slurry simulant

    International Nuclear Information System (INIS)

    Rappe, K.G.; Gauglitz, P.A.

    1998-08-01

    At the Savannah River Site, the in-tank precipitation (ITP) process uses sodium tetraphenylborate (NaTPB) to precipitate radioactive cesium from alkaline wastes. During this process, potassium is also precipitated to form 4-wt% KTPB/CsTPB slurry. Residual NaTPB decomposes to form benzene, which is retained by the waste slurry. The retained benzene is also readily released from the waste during subsequent waste processing. While the release of benzene certainly poses flammability and toxicological safety concerns, the magnitude of the hazard depends on the rate of release. Currently, the mechanisms controlling the benzene release rates are not well understood, and predictive models for estimating benzene release rates are not available. The overall purpose of this study is to obtain quantitative measurements of benzene release rates from a series of ITP slurry simulants. This information will become a basis for developing a quantitative mechanistic model of benzene release rates. The transient benzene release rate was measured from the surface of various ITP slurry (solution) samples mixed with benzene. The benzene release rate was determined by continuously purging the headspace of a sealed sample vessel with an inert gas (nitrogen) and analyzing that purged headspace vapor for benzene every minute

  13. Adsorptive Removal of Benzene and Toluene from Aqueous Environments by Cupric Oxide Nanoparticles: Kinetics and Isotherm Studies

    Directory of Open Access Journals (Sweden)

    Leili Mohammadi

    2017-01-01

    Full Text Available Removal of benzene and toluene, as the major pollutants of water resources, has attracted researchers’ attention, given the risk they pose to human health. In the present study, the potential of copper oxide nanoparticles (CuO-NPs in eliminating benzene and toluene from a mixed aqueous solution was evaluated. For this, we performed batch experiments to investigate the effect of solution pH (3–13, dose of CuO-NPs (0.1–0.8 g, contact time (5–120 min, and concentration of benzene and toluene (10–200 mg/l on sorption efficiency. The maximum removal was observed at neutral pH. By using the Langmuir model, we measured the highest adsorption capacity to be 100.24 mg/g for benzene and 111.31 mg/g for toluene. Under optimal conditions, adsorption efficiency was 98.7% and 92.5% for benzene and toluene, respectively. The sorption data by CuO-NPs well fitted into the following models: Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich model. The experimental information well fitted in the Freundlich for benzene and Langmuir for toluene. Based on the results, adsorption followed pseudo-second-order kinetics with acceptable coefficients. The findings introduced CuO-NPs as efficient compounds in pollutants adsorption. In fact, they could be used to develop a simple and efficient pollutant removal method from aqueous solutions.

  14. Small-angle neutron scattering studies of sodium butyl benzene ...

    Indian Academy of Sciences (India)

    shape and size of the aggregates of sodium n-butyl benzene sulfonate in aqueous solutions. To the best of our knowledge this is the first SANS report on the aggre- gation behaviour of a hydrotrope in aqueous solutions. 2. Materials and methods n-Butyl benzene, procured from Herdilia Chemicals, Mumbai, was sulfonated ...

  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

    2016-03-15

    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. 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

  17. 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. Copyright © 2015. Published by Elsevier B.V.

  18. Chromosome-wide aneuploidy study (CWAS) in workers exposed to an established leukemogen, benzene

    Science.gov (United States)

    Zhang, Luoping; Lan, Qing; Guo, Weihong; Hubbard, Alan E.; Li, Guilan; Rappaport, Stephen M.; McHale, Cliona M.; Shen, Min; Ji, Zhiying; Vermeulen, Roel; Yin, Songnian; Rothman, Nathaniel; Smith, Martyn T.

    2011-01-01

    Evidence suggests that de novo, therapy-related and benzene-induced acute myeloid leukemias (AML) occur via similar cytogenetic and genetic pathways, several of which involve aneuploidy, the loss or gain of chromosomes. Aneuploidy of specific chromosomes has been detected in benzene-related leukemia patients as well as in healthy benzene-exposed workers, suggesting that aneuploidy precedes and may be a potential mechanism underlying benzene-induced leukemia. Here, we analyzed the peripheral blood lymphocytes of 47 exposed workers and 27 unexposed controls using a novel OctoChrome fluorescence in situ hybridization (FISH) technique that simultaneously detects aneuploidy in all 24 chromosomes. Through this chromosome-wide aneuploidy study (CWAS) approach, we found heterogeneity in the monosomy and trisomy rates of the 22 autosomes when plotted against continuous benzene exposure. In addition, statistically significant, chromosome-specific increases in the rates of monosomy [5, 6, 7, 10, 16 and 19] and trisomy [5, 6, 7, 8, 10, 14, 16, 21 and 22] were found to be dose dependently associated with benzene exposure. Furthermore, significantly higher rates of monosomy and trisomy were observed in a priori defined ‘susceptible’ chromosome sets compared with all other chromosomes. Together, these findings confirm that benzene exposure is associated with specific chromosomal aneuploidies in hematopoietic cells, which suggests that such aneuploidies may play roles in benzene-induced leukemogenesis. PMID:21216845

  19. [Studies of ozone formation potentials for benzene and ethylbenzene using a smog chamber and model simulation].

    Science.gov (United States)

    Jia, Long; Xu, Yong-Fu

    2014-02-01

    Ozone formation potentials from irradiations of benzene-NO(x) and ethylbenzene-NO(x) systems under the conditions of different VOC/NO(x) ratios and RH were investigated using a characterized chamber and model simulation. The repeatability of the smog chamber experiment shows that for two sets of ethylbenzene-NO(x) irradiations with similar initial concentrations and reaction conditions, such as temperature, relative humidity and relative light intensity, the largest difference in O3 between two experiments is only 4% during the whole experimental run. On the basis of smog chamber experiments, ozone formation of photo-oxidation of benzene and ethylbenzene was simulated in terms of the master chemical mechanism (MCM). The peak ozone values for benzene and ethylbenzene simulated by MCM are higher than the chamber data, and the difference between the MCM-simulated results and chamber data increases with increasing RH. Under the conditions of sunlight irradiations, with benzene and ethylbenzene concentrations being in the range of (10-50) x 10(-9) and NO(x) concentrations in the range of (10-100) x 10(-9), the 6 h ozone contributions of benzene and ethylbenzene were obtained to be (3.1-33) x 10(-9) and (2.6-122) x 10(-9), whereas the peak O3 contributions of benzene and ethylbenzene were (3.5-54) x 10(-9) and (3.8-164) x 10(-9), respectively. The MCM-simulated maximum incremental reactivity (MIR) values for benzene and ethylbenzene were 0.25/C and 0.97/C (per carbon), respectively. The maximum ozone reactivity (MOR) values for these two species were obtained to be 0.73/C and 1.03/C, respectively. The MOR value of benzene from MCM is much higher than that obtained by carter from SAPRC, indicating that SAPRC may underestimate the ozone formation potential of benzene.

  20. 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.

  1. The use of biomonitoring data in exposure and human health risk assessment: benzene case study.

    Science.gov (United States)

    Arnold, Scott M; Angerer, Juergen; Boogaard, Peter J; Hughes, Michael F; O'Lone, Raegan B; Robison, Steven H; Schnatter, A Robert

    2013-02-01

    Abstract A framework of "Common Criteria" (i.e. a series of questions) has been developed to inform the use and evaluation of biomonitoring data in the context of human exposure and risk assessment. The data-rich chemical benzene was selected for use in a case study to assess whether refinement of the Common Criteria framework was necessary, and to gain additional perspective on approaches for integrating biomonitoring data into a risk-based context. The available data for benzene satisfied most of the Common Criteria and allowed for a risk-based evaluation of the benzene biomonitoring data. In general, biomarker (blood benzene, urinary benzene and urinary S-phenylmercapturic acid) central tendency (i.e. mean, median and geometric mean) concentrations for non-smokers are at or below the predicted blood or urine concentrations that would correspond to exposure at the US Environmental Protection Agency reference concentration (30 µg/m(3)), but greater than blood or urine concentrations relating to the air concentration at the 1 × 10(-5) excess cancer risk (2.9 µg/m(3)). Smokers clearly have higher levels of benzene exposure, and biomarker levels of benzene for non-smokers are generally consistent with ambient air monitoring results. While some biomarkers of benzene are specific indicators of exposure, the interpretation of benzene biomonitoring levels in a health-risk context are complicated by issues associated with short half-lives and gaps in knowledge regarding the relationship between the biomarkers and subsequent toxic effects.

  2. The use of biomonitoring data in exposure and human health risk assessment: benzene case study

    Science.gov (United States)

    Angerer, Juergen; Boogaard, Peter J.; Hughes, Michael F.; O’Lone, Raegan B.; Robison, Steven H.; Robert Schnatter, A.

    2013-01-01

    A framework of “Common Criteria” (i.e. a series of questions) has been developed to inform the use and evaluation of biomonitoring data in the context of human exposure and risk assessment. The data-rich chemical benzene was selected for use in a case study to assess whether refinement of the Common Criteria framework was necessary, and to gain additional perspective on approaches for integrating biomonitoring data into a risk-based context. The available data for benzene satisfied most of the Common Criteria and allowed for a risk-based evaluation of the benzene biomonitoring data. In general, biomarker (blood benzene, urinary benzene and urinary S-phenylmercapturic acid) central tendency (i.e. mean, median and geometric mean) concentrations for non-smokers are at or below the predicted blood or urine concentrations that would correspond to exposure at the US Environmental Protection Agency reference concentration (30 µg/m3), but greater than blood or urine concentrations relating to the air concentration at the 1 × 10−5 excess cancer risk (2.9 µg/m3). Smokers clearly have higher levels of benzene exposure, and biomarker levels of benzene for non-smokers are generally consistent with ambient air monitoring results. While some biomarkers of benzene are specific indicators of exposure, the interpretation of benzene biomonitoring levels in a health-risk context are complicated by issues associated with short half-lives and gaps in knowledge regarding the relationship between the biomarkers and subsequent toxic effects. PMID:23346981

  3. 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.

  4. 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

    2016-01-01

    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.

  5. CCDC 1427127: Experimental Crystal Structure Determination : bis(1,10-Phenanthroline)-copper heptafluorobutanoate benzene solvate

    KAUST Repository

    Huang, Yangjie

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  6. Experimental studies

    International Nuclear Information System (INIS)

    Cowser, K.E.; Stansbury, P.S.; Poston, J.W.; Deus, S.F.; Chen, W.L.; Roswell, R.L.; Goans, R.E.; Cantrell, J.H. Jr.

    1978-01-01

    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

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

    International Nuclear Information System (INIS)

    Norinaga, Koyo; Yang, Huamei; Tanaka, Ryota; Appari, Srinivas; Iwanaga, Keita; Takashima, Yuka; Kudo, Shinji; Shoji, Tetsuya; Hayashi, Jun-ichiro

    2014-01-01

    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. C 3 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

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

    Indian Academy of Sciences (India)

    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 ...

  9. 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.

  10. CCDC 1063885: Experimental Crystal Structure Determination : (2-(bis(2-methoxyphenyl)phosphanyl)benzene-1-sulfonato)-(1-(furan-2-yl)ethan-1-ido)-palladium benzene solvate

    KAUST Repository

    Jian, Zhongbao

    2017-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  11. Benzene oxidation coupled to sulfate reduction

    Science.gov (United States)

    Lovley, D.R.; Coates, J.D.; Woodward, J.C.; Phillips, E.J.P.

    1995-01-01

    Highly reduced sediments from San Diego Bay, Calif., that were incubated under strictly anaerobic conditions metabolized benzene within 55 days when they were exposed initially to I ??M benzene. The rate of benzene metabolism increased as benzene was added back to the benzene-adapted sediments. When a [14C]benzene tracer was included with the benzene added to benzene-adapted sediments, 92% of the added radioactivity was recovered as 14CO2. Molybdate, an inhibitor of sulfate reduction, inhibited benzene uptake and production of 14CO2 from [14C]benzene. Benzene metabolism stopped when the sediments became sulfate depleted, and benzene uptake resumed when sulfate was added again. The stoichiometry of benzene uptake and sulfate reduction was consistent with the hypothesis that sulfate was the principal electron acceptor for benzene oxidation. Isotope trapping experiments performed with [14C]benzene revealed that there was no production of such potential extracellular intermediates of benzene oxidation as phenol, benzoate, p-hydroxybenzoate, cyclohexane, catechol, and acetate. The results demonstrate that benzene can be oxidized in the absence of O2, with sulfate serving as the electron acceptor, and suggest that some sulfate reducers are capable of completely oxidizing benzene to carbon dioxide without the production of extracellular intermediates. Although anaerobic benzene oxidation coupled to chelated Fe(III) has been documented previously, the study reported here provides the first example of a natural sediment compound that can serve as an electron acceptor for anaerobic benzene oxidation.

  12. A retrospective cohort study of cause-specific mortality and incidence of hematopoietic malignancies in Chinese benzene-exposed workers.

    Science.gov (United States)

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

    2015-11-01

    Benzene exposure has been causally linked with acute myeloid leukemia (AML), but inconsistently associated with other hematopoietic, lymphoproliferative and related disorders (HLD) or solid tumors in humans. Many neoplasms have been described in experimental animals exposed to benzene. We used Poisson regression to estimate adjusted relative risks (RR) and the likelihood ratio statistic to derive confidence intervals for cause-specific mortality and HLD incidence in 73,789 benzene-exposed compared with 34,504 unexposed workers in a retrospective cohort study in 12 cities in China. Follow-up and outcome assessment was based on factory, medical and other records. Benzene-exposed workers experienced increased risks for all-cause mortality (RR = 1.1, 95% CI = 1.1, 1.2) due to excesses of all neoplasms (RR = 1.3, 95% CI = 1.2, 1.4), respiratory diseases (RR = 1.7, 95% CI = 1.2, 2.3) and diseases of blood forming organs (RR = ∞, 95% CI = 3.4, ∞). Lung cancer mortality was significantly elevated (RR = 1.5, 95% CI = 1.2, 1.9) with similar RRs for males and females, based on three-fold more cases than in our previous follow-up. Significantly elevated incidence of all myeloid disorders reflected excesses of myelodysplastic syndrome/acute myeloid leukemia (RR = 2.7, 95% CI = 1.2, 6.6) and chronic myeloid leukemia (RR = 2.5, 95% CI = 0.8, 11), and increases of all lymphoid disorders included excesses of non-Hodgkin lymphoma (RR = 3.9, 95%CI = 1.5, 13) and all lymphoid leukemia (RR = 5.4, 95%CI = 1.0, 99). The 28-year follow-up of Chinese benzene-exposed workers demonstrated increased risks of a broad range of myeloid and lymphoid neoplasms, lung cancer, and respiratory diseases and suggested possible associations with other malignant and non-malignant disorders. © 2015 UICC.

  13. Occupational Exposure to Benzene and Non-Hodgkin Lymphoma in a Population-Based Cohort: The Shanghai Women's Health Study.

    Science.gov (United States)

    Bassig, Bryan A; Friesen, Melissa C; Vermeulen, Roel; Shu, Xiao-Ou; Purdue, Mark P; Stewart, Patricia A; Xiang, Yong-Bing; Chow, Wong-Ho; Zheng, Tongzhang; Ji, Bu-Tian; Yang, Gong; Linet, Martha S; Hu, Wei; Zhang, Heping; Zheng, Wei; Gao, Yu-Tang; Rothman, Nathaniel; Lan, Qing

    2015-10-01

    The association between benzene exposure and non-Hodgkin lymphoma (NHL) has been the subject of debate as a result of inconsistent epidemiologic evidence. An International Agency for Research on Cancer (IARC) working group evaluated benzene in 2009 and noted evidence for a positive association between benzene exposure and NHL risk. We evaluated the association between occupational benzene exposure and NHL among 73,087 women enrolled in the prospective population-based Shanghai Women's Health Study. Benzene exposure estimates were derived using a previously developed exposure assessment framework that combined ordinal job-exposure matrix intensity ratings with quantitative benzene exposure measurements from an inspection database of Shanghai factories collected between 1954 and 2000. Associations between benzene exposure metrics and NHL (n = 102 cases) were assessed using Cox proportional hazard models, with study follow-up occurring from December 1996 through December 2009. Women ever exposed to benzene had a significantly higher risk of NHL [hazard ratio (HR) = 1.87, 95% CI: 1.19, 2.96]. Compared with unexposed women, significant trends in NHL risk were observed for increasing years of benzene exposure (p(trend) = 0.006) and increasing cumulative exposure levels (p(trend) = 0.005), with the highest duration and cumulative exposure tertiles having a significantly higher association with NHL (HR = 2.07, 95% CI: 1.07, 4.01 and HR = 2.16, 95% CI: 1.17, 3.98, respectively). Our findings, using a population-based prospective cohort of women with diverse occupational histories, provide additional evidence that occupational exposure to benzene is associated with NHL risk.

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

    International Nuclear Information System (INIS)

    Barega, Esayas W.; Zondervan, Edwin; Haan, André B. de

    2013-01-01

    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

  15. A retrospective cohort study of leukemia and other cancers in benzene workers

    Energy Technology Data Exchange (ETDEWEB)

    Yin, S.N.; Li, G.L.; Tain, F.D.; Fu, Z.I.; Jin, C. (Chinese Academy of Preventive Medicine, Beijing (China)); Chen, Y.J. (Station for Health and Prevention of Infection of Shanghai (China)); Luo, S.J. (Station for Health and Prevention of Infection of Sichuan (China)); Ye, P.Z. (Station for Health and Prevention of Infection of Tianjin (China)); Zhang, J.Z. (Station for Health and Prevention of Infection of Nanchang (China)); Wang, G.C. (China Institute for Prevention and Treatment of Occupational Disease of Heilongjing (China)); Zhang, X.C. (China Institute for Prevention and Treatment of Occupational Disease of Shenyang (China)); Wu, H.N. (China Institute for Prevention and Treatment of Occupational Disease of Helan (China)); Zhong, Q.C. (China Institute for Prevention and Treatment of Occupational Disease of Guangzhou (China))

    1989-07-01

    A retrospective cohort study was carried out in 1982-1983 among 28,460 benzene-exposed workers (15,643 males, 12,817 females) from 233 factories and 28,257 control workers (16,621 males, 12,366 females) from 83 factories in 12 large cities in China. All-cause mortality was significantly higher among the exposed than among the unexposed, as was mortality from all malignant neoplasms. For certain cancers, increased mortality was noted among benzene-exposed males in comparison with that among unexposed males; the standardized mortality ratios (SMR) were elevated for leukemia, lung cancer, primary hepatocarcinoma, and stomach cancer. For females only leukemia occurred in excess among the exposed. Risk of leukemia rose as duration to exposure to benzene increased up to 15 years, and then declined with additional years of exposure. Leukemia occurred among some workers with as little as 6 to 10 ppm average exposure and 50 ppm-years (or possibly less) cumulative lifetime exposure. During 1972 to 1981, the annual incidence of leukemia ranged from 5.83 to 28.33 per 100,000 with higher rates occurring in the interval 1977 to 1981 than in the earlier years of the study period. Future studies should evaluate more precisely the relationship between exposure levels, job title, and development of leukemia among cases and noncases within the exposed cohort.

  16. Aromaticity in benzene-like rings – An experimental electron density ...

    Indian Academy of Sciences (India)

    Unknown

    multitude of experimental and theoretical methods.1 Experimental methods include spectroscopic techniques such as NMR,2 X-ray crystallography and magnetic measure- ments,3 while theoretical approaches mainly pertain to resonance energy calculations4 and graph-topological evaluations.5 Although there are a ...

  17. Benzene exposure among auto-repair workers from workplace ambience: a pioneer study from Pakistan.

    Science.gov (United States)

    Kamal, Atif; Rashid, Audil

    2014-10-01

    In Pakistan, the reports on benzene exposure among workers in chemical industries are almost non-existing due to limited research work in the field of exposure science. This study aimed to investigate such exposure in a widely adopted occupation in Rawalpindi city. In this cross-sectional study, 60 blood samples (N = 20/group) of mechanics (MCs), spray painters (PNs) and control participants (CN) were analyzed. The socio-economic and demographic information of workers and that of workplaces was documented using a short questionnaire. We identified that the workers in spray-painting occupation are highly at risk of benzene exposure. The results showed that PNs were more at risk of exposure to benzene than MCs, and this exposure was significantly correlated with long working hours (r = 0.68, p chemicals, other identified predictors of exposure included active and passive smoking, poor workplace hygiene and substandard ventilation. To mitigate workplace exposure, it is necessary to reduce working hours and encourage regular use of self-protective equipments and adoption of proper hygiene in chemical workplaces.

  18. 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.

  19. 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)

    Almeida, Kelly Cristina Santana de

    2006-01-01

    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 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 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)

  20. Collision lifetimes of polyatomic molecules at low temperatures: benzene-benzene vs benzene-rare gas atom collisions.

    Science.gov (United States)

    Cui, Jie; Li, Zhiying; Krems, Roman V

    2014-10-28

    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.

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

    International Nuclear Information System (INIS)

    Bahadar, Haji; Mostafalou, Sara; Abdollahi, Mohammad

    2014-01-01

    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

  2. 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

  3. Studies on cytogenetic effects induced by chronic γ-radiation combined with benzene, toluene and carbon monoxide inhalation in animals

    International Nuclear Information System (INIS)

    Zhang Hongyuan; Wang Yuexing; Wang Lanjin; Pan Yan

    1998-01-01

    8 experimental groups were conducted according to four factors two doses orthogonal layout [L8(2 7 )] in present investigation. 90 healthy male rabbits and 90 healthy male mice were equally divided into 8 experimental groups and control group. Exprimental animals were exposed to γ-radiation combined with benzene, toluene and CO vapour for 2h per day, 5 days per week for 8 weeks. Two doses of γ-radiation, benzene, toluene and CO were 0.0375 and 0.0075 Gy/d (for rabbits, 0.0473 and 0.0095 Gy/d for mice), 182 +- 33 and 40 +- 15 mg/m 3 , 407 +- 68 and 90 +- 39 mg/m 3 as well as 278 +- 18 mg/m 3 , respectively. The main results were showed as follows: (1) γ-radiation, benzene and toluene could all induce chromosome aberration, SCEs and micronuclei of lymphocytes in rabbits and chromosome aberrations of bone marrow cells in rabbits and mice, but those was no observed in carbon monoxide. (2) γ-radiation and benzene induced chromosome aberrations and micronuclei of lymphocytes in rabbits as well as chromosome aberrations of bone marrow cells in mice, γ-radiation and toluene induced chromosome aberrations of lymphocytes (in rabbits) and bone marrow cells (in mice), benzene and toluene induced chromosome aberrations of lymphocytes (in rabbits) and bone marrow cells (in mice). They showed all significantly interaction. (3) In combined effects, the yield of chromosome aberrations, SCEs and micronuclei induced by (1) experimental groups which four factors are all high doses were highest, however, those by induced (8) experimental groups which four factors are all low doses also were higher than those of control group and there were statistical difference except SCEs

  4. Benzene Monitor System report

    International Nuclear Information System (INIS)

    Livingston, R.R.

    1992-01-01

    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/PRclose 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 ampersand 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)

  5. Retrospective benzene and total hydrocarbon exposure assessment for a petroleum marketing and distribution worker epidemiology study.

    Science.gov (United States)

    Armstrong, T W; Pearlman, E D; Schnatter, A R; Bowes, S M; Murray, N; Nicolich, M J

    1996-04-01

    A quantitative exposure-estimating algorithm for benzene and total hydrocarbons was developed for a case control study of petroleum marketing and distribution workers. The algorithm used a multiplicative model to adjust recently measured quantitative exposure data to past scenarios for which representative exposure measurement data did not exist. This was accomplished through the development of exposure modifiers to account for differences in the workplace, the materials handled, the environmental conditions, and the tasks performed. Values for exposure modifiers were obtained empirically and through physical/chemical relationships. Dates for changes that altered exposure potential were obtained from archive records, retired employee interviews, and from current operations personnel. Exposure modifiers were used multiplicatively, adjusting available measured data to represent the relevant exposure scenario and time period. Changes in exposure modifiers translated to step changes in exposure estimates. Though limited by availability of data, a validation exercise suggested that the algorithm provided accurate exposure estimates for benzene (compared with measured data in industrial hygiene survey reports); the estimates generally differed by an average of less than 20% from the measured values. This approach is proposed to quantify exposures retrospectively where there are sufficient data to develop reliable current era estimates and where a historical accounting of key exposure modifiers can be developed, but where there are insufficient historic exposure measurements to directly assess historic exposures.

  6. Exposure to benzene in a pooled analysis of petroleum industry case-control studies.

    Science.gov (United States)

    Glass, D C; Schnatter, A R; Tang, G; Armstrong, T W; Rushton, L

    2017-11-01

    Cases of lymphohematopoietic cancer from three petroleum industry cohorts, matched to controls from the respective cohort, were pooled into single study. Average benzene exposure was quantitatively estimated in ppm for each job based on measured data from the relevant country, adjusted for the specific time period, site and job exposure characteristics and the certainty of the exposure estimate scored. The probability of dermal exposure and of peak exposure was also assessed. Before risk was examined, an exposure estimate comparison and rationalisation exercise was performed across the studies to ensure accuracy and consistency of approach. This article evaluates the final exposure estimates and their use in the risk assessments. Overall benzene exposure estimates were low: 90% of participants accumulated less than 20 ppm-years. Mean cumulative exposure was estimated as 5.15 ppm-years, mean duration was 22 years, and mean exposure intensity was 0.2 ppm. 46% of participants were allocated a peak exposure (>3 ppm at least weekly). 40% of participants had a high probability of dermal exposure (based on the relative probability of at least weekly exposure). There were differences in mean intensity of exposure, probability of peak, and/or dermal exposure associated with job category, job site, and decade of exposure. Terminal Operators handling benzene-containing products were the most highly exposed group, followed by Tanker Drivers carrying gasoline. Exposures were higher around 1940-1950 and lower in more recent decades. Overall confidence in the exposure estimates was highest for recently held jobs and for white-collar jobs. We used sensitivity analyses, which included and excluded case-sets on the basis of exposure certainty scores, to inform the risk assessment. The above analyses demonstrated that the different patterns of exposure across the three studies are largely attributable to differences in jobs, site types, and time frames rather than study. This

  7. [Study on repair capacity of DNA damage associated with chronic benzene poisoning].

    Science.gov (United States)

    Xing, Cai-hong; Ji, Zhi-ying; Li, Gui-lan; Yin, Song-nian

    2006-07-01

    To explore the repair capacity of DNA damage associated with chronic benzene poisonings. 63 workers suffered from chronic benzene poisonings and 45 workers exposed to benzene, who were engaged in the same job title, were investigated. Comet assay and cytokinesis-block micronucleus (CBMN) detection were used to evaluate gamma-radiation-induced DNA and chromosomal damage and repair capacity in peripheral blood lymphocyte. The comet tail length difference of the benzene poisoning group (4.64 +/- 1.57 microm) was significantly higher than that of the control group (3.77 +/- 1.30 microm) (P = 0.0029). There was no significant difference of the 3AB index between the poisoning group and the control group. The relative risk of benzene poisoning in the subject with comet tail length difference > 3.81 was significantly higher than that in the subject with comet tail length difference poisoning in the subject with 3AB index or = 0.20. DNA repair capacity on DNA-strand level might tightly associate with chronic benzene poisoning. The DNA repair capacity on DNA-strand level would be worse, and the benzene poisoning risk could be higher. There was no clear relation between the DNA repair capacity on chromosome level and the benzene poisoning risk.

  8. Urinary benzene biomarkers and DNA methylation in Bulgarian petrochemical workers: study findings and comparison of linear and beta regression models.

    Directory of Open Access Journals (Sweden)

    Wei Jie Seow

    Full Text Available Chronic occupational exposure to benzene is associated with an increased risk of hematological malignancies such as acute myeloid leukemia (AML, but the underlying mechanisms are still unclear. The main objective of this study was to investigate the association between benzene exposure and DNA methylation, both in repeated elements and candidate genes, in a population of 158 Bulgarian petrochemical workers and 50 unexposed office workers. Exposure assessment included personal monitoring of airborne benzene at work and urinary biomarkers of benzene metabolism (S-phenylmercapturic acid [SPMA] and trans,trans-muconic acid [t,t-MA] at the end of the work-shift. The median levels of airborne benzene, SPMA and t,t-MA in workers were 0.46 ppm, 15.5 µg/L and 711 µg/L respectively, and exposure levels were significantly lower in the controls. Repeated-element DNA methylation was measured in Alu and LINE-1, and gene-specific methylation in MAGE and p15. DNA methylation levels were not significantly different between exposed workers and controls (P>0.05. Both ordinary least squares (OLS and beta-regression models were used to estimate benzene-methylation associations. Beta-regression showed better model specification, as reflected in improved coefficient of determination (pseudo R(2 and Akaike's information criterion (AIC. In beta-regression, we found statistically significant reductions in LINE-1 (-0.15%, P<0.01 and p15 (-0.096%, P<0.01 mean methylation levels with each interquartile range (IQR increase in SPMA. This study showed statistically significant but weak associations of LINE-1 and p15 hypomethylation with SPMA in Bulgarian petrochemical workers. We showed that beta-regression is more appropriate than OLS regression for fitting methylation data.

  9. CCDC 897158: Experimental Crystal Structure Determination : (2-(bis(2-methoxyphenyl)phosphino)benzenesulfonato)(hydrido)(tri-t-butylphosphine)palladium benzene solvate

    KAUST Repository

    Rünzi, Thomas

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  10. CCDC 1440203: Experimental Crystal Structure Determination : dodecakis(mu-benzene-1,3-dithiolato)-tetrakis(triphenylphosphine)-gold-octacosa-silver

    KAUST Repository

    Soldan, Giada

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  11. 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...

  12. Fuel Dependence of Benzene Pathways

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H; Eddings, E; Sarofim, A; Westbrook, C

    2008-07-14

    The relative importance of formation pathways for benzene, an important precursor to soot formation, was determined from the simulation of 22 premixed flames for a wide range of equivalence ratios (1.0 to 3.06), fuels (C{sub 1}-C{sub 12}), and pressures (20 to 760 torr). The maximum benzene concentrations in 15 out of these flames were well reproduced within 30% of the experimental data. Fuel structural properties were found to be critical for benzene production. Cyclohexanes and C{sub 3} and C{sub 4} fuels were found to be among the most productive in benzene formation; and long-chain normal paraffins produce the least amount of benzene. Other properties, such as equivalence ratio and combustion temperatures, were also found to be important in determining the amount of benzene produced in flames. Reaction pathways for benzene formation were examined critically in four premixed flames of structurally different fuels of acetylene, n-decane, butadiene, and cyclohexane. Reactions involving precursors, such as C{sub 3} and C{sub 4} species, were examined. Combination reactions of C{sub 3} species were identified to be the major benzene formation routes with the exception of the cyclohexane flame, in which benzene is formed exclusively from cascading fuel dehydrogenation via cyclohexene and cyclohexadiene intermediates. Acetylene addition makes a minor contribution to benzene formation, except in the butadiene flame where C{sub 4}H{sub 5} radicals are produced directly from the fuel, and in the n-decane flame where C{sub 4}H{sub 5} radicals are produced from large alkyl radical decomposition and H atom abstraction from the resulting large olefins.

  13. Disproportionation of Trimethyl Benzenes over Large Pore Zeolites: Catalytic and Adsorption Study

    Czech Academy of Sciences Publication Activity Database

    Čejka, Jiří; Kotrla, Josef; Krejčí, Andrea

    2004-01-01

    Roč. 277, 1/2 (2004), s. 191-199 ISSN 0926-860X R&D Projects: GA ČR GA104/99/0840; GA AV ČR IBS4040015 Institutional research plan: CEZ:AV0Z4040901 Keywords : trimethyl benzenes * xylenes * tetramethyl benzenes * disproportionation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.378, year: 2004

  14. Leukemia and Benzene

    Science.gov (United States)

    Snyder, Robert

    2012-01-01

    Excessive exposure to benzene has been known for more than a century to damage the bone marrow resulting in decreases in the numbers of circulating blood cells, and ultimately, aplastic anemia. Of more recent vintage has been the appreciation that an alternative outcome of benzene exposure has been the development of one or more types of leukemia. While many investigators agree that the array of toxic metabolites, generated in the liver or in the bone marrow, can lead to traumatic bone marrow injury, the more subtle mechanisms leading to leukemia have yet to be critically dissected. This problem appears to have more general interest because of the recognition that so-called “second cancer” that results from prior treatment with alkylating agents to yield tumor remissions, often results in a type of leukemia reminiscent of benzene-induced leukemia. Furthermore, there is a growing literature attempting to characterize the fine structure of the marrow and the identification of so called “niches” that house a variety of stem cells and other types of cells. Some of these “niches” may harbor cells capable of initiating leukemias. The control of stem cell differentiation and proliferation via both inter- and intra-cellular signaling will ultimately determine the fate of these transformed stem cells. The ability of these cells to avoid checkpoints that would prevent them from contributing to the leukemogenic response is an additional area for study. Much of the study of benzene-induced bone marrow damage has concentrated on determining which of the benzene metabolites lead to leukemogenesis. The emphasis now should be directed to understanding how benzene metabolites alter bone marrow cell biology. PMID:23066403

  15. High level theoretical study of binding and of the potential energy surface in benzene-hydride system

    Energy Technology Data Exchange (ETDEWEB)

    Coletti, Cecilia, E-mail: ccoletti@unich.it [Dipartimento di Scienze del Farmaco, Universita ' G. d' Annunzio' Chieti-Pescara, Via dei Vestini 31, 66100 Chieti (Italy); Re, Nazzareno [Dipartimento di Scienze del Farmaco, Universita ' G. d' Annunzio' Chieti-Pescara, Via dei Vestini 31, 66100 Chieti (Italy)

    2012-04-04

    Graphical abstract: In-plane minimum geometries for benzene-H{sup -} non-covalent adducts: linear adduct (left) with the hydride ion hydrogen bonded to one aromatic hydrogen; bifurcated adduct (right), with the hydride ion hydrogen bonded to two adjacent aromatic hydrogens. Highlights: Black-Right-Pointing-Pointer Theoretical study on covalent and non-covalent binding in benzene-hydride. Black-Right-Pointing-Pointer Two non-covalent stable adducts were characterized in the in-plane geometry. Black-Right-Pointing-Pointer Significant sections of the potential energy surface were determined. Black-Right-Pointing-Pointer Formation of a very stable C{sub 6}H{sub 7}{sup -} anion upon covalent binding to carbon. - Abstract: High level ab initio calculations were performed on the interaction of the hydride anion with benzene, a system of potential interest for modelling the interactions occurring in hydrogen rich planetary atmospheres. We investigated both non-covalent and covalent binding, exploring the complete basis set limit using highly correlated MP2 and CCSD(T) levels of theory. Two non-covalent minima on the potential energy surface have been characterized, and found to correspond to moderately strong hydrogen bonding interactions. To gain further insight on the nature of binding, the total interaction energy was decomposed into its physically meaningful components and selected sections of the potential energy surface were calculated. Moreover, we found that H{sup -} can easily covalently bind to one of the carbon atoms of benzene to form a stable C{sub 6}H{sub 7}{sup -} anion, a global minimum on the potential energy surface, characterized by a puckered geometry, with a carbon atom bending out of the benzene plane. A slightly less stable planar C{sub 6}H{sub 7}{sup -} structure was also identified, corresponding to the transition state for the flipping motion of the puckered species.

  16. Benzene degradation in a denitrifying biofilm reactor

    OpenAIRE

    Waals, van der, Marcelle J.; Atashgahi, Siavash; Rocha, da, Ulisses Nunes; Zaan, van der, Bas M.; Smidt, Hauke; Gerritse, Jan

    2017-01-01

    Benzene is an aromatic compound and harmful for the environment. Biodegradation of benzene can reduce the toxicological risk after accidental or controlled release of this chemical in the environment. In this study, we further characterized an anaerobic continuous biofilm culture grown for more than 14 years on benzene with nitrate as electron acceptor. We determined steady state degradation rates, microbial community composition dynamics in the biofilm, and the initial anaerobic benzene degr...

  17. 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.

  18. Structures and energetics of complexation of metal ions with ammonia, water, and benzene: A computational study.

    Science.gov (United States)

    Sharma, Bhaskar; Neela, Y Indra; Narahari Sastry, G

    2016-04-30

    Quantum chemical calculations have been performed at CCSD(T)/def2-TZVP level to investigate the strength and nature of interactions of ammonia (NH3 ), water (H2 O), and benzene (C6 H6 ) with various metal ions and validated with the available experimental results. For all the considered metal ions, a preference for C6 H6 is observed for dicationic ions whereas the monocationic ions prefer to bind with NH3 . Density Functional Theory-Symmetry Adapted Perturbation Theory (DFT-SAPT) analysis has been employed at PBE0AC/def2-TZVP level on these complexes (closed shell), to understand the various energy terms contributing to binding energy (BE). The DFT-SAPT result shows that for the metal ion complexes with H2 O electrostatic component is the major contributor to the BE whereas, for C6 H6 complexes polarization component is dominant, except in the case of alkali metal ion complexes. However, in case of NH3 complexes, electrostatic component is dominant for s-block metal ions, whereas, for the d and p-block metal ion complexes both electrostatic and polarization components are important. The geometry (M(+) -N and M(+) -O distance for NH3 and H2 O complexes respectively, and cation-π distance for C6 H6 complexes) for the alkali and alkaline earth metal ion complexes increases down the group. Natural population analysis performed on NH3 , H2 O, and C6 H6 complexes shows that the charge transfer to metal ions is higher in case of C6 H6 complexes. © 2015 Wiley Periodicals, Inc.

  19. Parental occupational exposure to benzene and the risk of childhood cancer: A census-based cohort study.

    Science.gov (United States)

    Spycher, Ben Daniel; Lupatsch, Judith Eva; Huss, Anke; Rischewski, Johannes; Schindera, Christina; Spoerri, Adrian; Vermeulen, Roel; Kuehni, Claudia Elisabeth

    2017-11-01

    Previous studies on occupational exposures in parents and cancer risks in their children support a link between solvents and paints with childhood leukaemia. Few studies have focused specifically on benzene. To examine whether parental occupational exposure to benzene is associated with an increased cancer risk in a census-based cohort of children. From a census-based cohort study in Switzerland, we included children aged benzene using a job exposure matrix. We identified incident cancer cases through record linkage with the Swiss Childhood Cancer Registry. We fitted Cox proportional-hazards models to assess associations between exposures and the following outcomes: any cancer, leukaemia, acute lymphoid leukaemia (ALL), acute myeloid leukaemia (AML), lymphoma, non-Hodgkin lymphoma, central nervous system (CNS) tumours, and glioma. We adjusted models for a range of socio-economic, perinatal and environmental factors. Analyses of maternal (paternal) exposure were based on 9.0 (13.2)millionperson years at risk and included 1004 (1520) cases of cancer, of which 285 (438) had leukaemia, 186 (281) lymphoma, 227 (339) a CNS tumour. Maternal exposure was associated with an increased risk of childhood leukaemia (hazard ratio 1.73, 95% CI 1.12-2.67) and ALL (1.88, 1.16-3.04). We found little evidence of an association for other outcomes or for paternal exposure. Adjusting for potential confounders did not materially affect the results. This nationwide cohort study suggests an increased risk of leukaemia among children whose mothers were exposed to benzene at work. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Comparative study of the LLE of the quaternary and ternary systems involving benzene, n-octane, n-decane and the ionic liquid [BMpyr][NTf2

    International Nuclear Information System (INIS)

    Requejo, Patricia F.; Calvar, Noelia; Domínguez, Ángeles; Gómez, Elena

    2016-01-01

    Highlights: • The ionic liquid BMpyrNTf 2 was evaluated as solvent to extract benzene from alkanes. • The quaternary system {octane + decane + benzene + BMpyrNTf 2 } was determined. • A comparison of results for ternary and quaternary systems was performed. • Experimental data were successfully correlated using the NRTL model. - Abstract: In this work, the suitability of the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [BMpyr][NTf 2 ], as an extraction agent to replace the traditional organic solvents in the separation of aromatic/aliphatic hydrocarbons was evaluated. Following this aim, the (liquid + liquid) equilibrium (LLE) of the quaternary system {n-octane (1) + n-decane (2) + benzene (3) + [BMpyr][NTf 2 ] (4)} and its corresponding ternary systems {n-octane or n-decane (1) + benzene (2) + [BMpyr][NTf 2 ] (3)} was determined at T = 298.15 K and at 101.3 kPa. Solute distribution ratio and selectivity were calculated from the experimental LLE values in order to evaluate the capability of this ionic liquid to accomplish the separation of benzene from its mixtures with n-octane and n-decane. A comparison of the results obtained from the LLE results of the ternary and quaternary systems was carried out. Finally, the experimental tie-lines compositions were correlated using the NRTL thermodynamic model.

  1. Structural study of a novel acetylide-thiourea derivative and its evaluation as a detector of benzene

    Science.gov (United States)

    Khairul, Wan M.; Daud, Adibah Izzati; Mohd Hanifaah, Noor Azura; Arshad, Suhana; Razak, Ibrahim Abdul; Zuki, Hafiza Mohamed; Erben, Mauricio F.

    2017-07-01

    The new derivative 1-hexanoyl-3-(4-p-tolylethynyl-phenyl)-thiourea (APHX) was synthesised by the addition reaction between 4[4-aminophenyl] ethynyltoluene and hexanoyl isothiocyanate in acetone. The acetylide group was incorporated by using Sonogashira cross-coupling reaction allowing for the preparation of acetylide-thiourea compound. APHX was then elucidated via single crystal X-ray crystallography analysis, spectroscopic and elemental analysis by Fourier Transform Infrared (FT-IR) spectroscopy, 1H and 13C Nuclear Magnetic Resonance (NMR), UV-visible analysis, CHNS-elemental analysis. APHX was also evaluated theoretically via density functional theory (DFT) approach. APHX was fabricated onto glass substrate via drop-cast technique prior to act as optical thin-film and its performance as volatile organic compounds (VOCs) sensor was investigated through the difference in UV-vis profile before and after exposure towards benzene. Preliminary findings revealed that APHX showed interaction towards benzene with about 48% sensitivity. According to thermogravimetric studies, APHX showed good thermal stability, without decomposition up to ca. 190 °C. Whilst, crystal structure of APHX consists in a nearly planar acylthiourea moiety with the Cdbnd O and Cdbnd S bonds utilizing trans position, favoring by an intramolecular Nsbnd H⋯Odbnd C hydrogen bonds. The alkyl chain is oriented 90° with respect to acylthiourea group. The phenyls group in the 1-methyl-4-(phenylethynyl)benzene moieties are mutually planar and slightly twisted with respect to the acylthiourea plane. Centrosymmetric dimers generated by intermolecular Nsbnd H⋯Sdbnd C and Csbnd H⋯Sdbnd C hydrogen bonds forming R22 (8) and R21(6) motifs are present in the crystals. The interaction between APHX with benzene has been modelled and calculated using density functional theory (DFT) via Gaussian 09 software package and the preferred sites of binding are located at the acylthiourea group.

  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. An Experimental Study

    African Journals Online (AJOL)

    The Role of the Learner's Native Culture in EFL Dictionaries: An Experimental Study. 567 strued. Many studies in ... that nativize texts have found that cultural familiarity (i.e. making use of the students' prior cultural ..... edge) when confronted with new information (in this case, when trying to understand the meaning of new ...

  4. Adsorption selectivity of benzene and propene mixtures for various zeolites

    NARCIS (Netherlands)

    Ban, S.|info:eu-repo/dai/nl/304837288; van Laak, A.N.C.|info:eu-repo/dai/nl/304833223; de Jongh, P.E.|info:eu-repo/dai/nl/186125372; van der Eerden, J.P.J.M.|info:eu-repo/dai/nl/068420471; Vlugt, T.J.H.|info:eu-repo/dai/nl/205040187

    2007-01-01

    The nine-site benzene model of Zhao et al. (J. Phys. Chem. B 2005, 109, 5368-5374) has been used to systematically study the adsorption of benzene, propene, and benzene-propene mixtures in zeolites mordenite, Y, , silicalite, and MCM22. Interaction parameters for the benzene-zeolite interactions

  5. Spectroscopic study on reaction mechanism of laser-ablated silicon ions and neutrals with benzene molecules

    Energy Technology Data Exchange (ETDEWEB)

    Saeki, M; Ohba, H; Yokoyama, A [Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan)

    2007-04-15

    Reaction of benzene molecules with ablated silicon ions and neutrals were investigated by space- and time-resolved optical emission spectroscopy. The time-resolved emission spectrum showed production of excited C{sub 2} and CH radicals after 180-ns delay from laser irradiation. Comparing the temporal evolution of C{sub 2}* with that of Si*, we concluded that the neutral Si atoms contribute to the production of the C{sub 2} radicals. The emission in a mixture of benzene vapor and neon gas suggested that the neutral Si atoms could excite the buffer atoms and molecules to high-energy levels. Based on the result, the production process of the C{sub 2} radicals is discussed.

  6. On the magnetic circular dichroism of benzene. A density-functional study

    Czech Academy of Sciences Publication Activity Database

    Kaminský, Jakub; Kříž, Jan; Bouř, Petr

    2017-01-01

    Roč. 146, č. 14 (2017), č. článku 144301. ISSN 0021-9606 R&D Projects: GA ČR GA13-03978S; GA ČR(CZ) GA16-05935S Institutional support: RVO:61388963 Keywords : magnetic circular dichroism * benzene * DFT Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 2.965, year: 2016

  7. Occupational Exposure to Benzene and Non-Hodgkin Lymphoma in a Population-Based Cohort: The Shanghai Women’s Health Study

    Science.gov (United States)

    Friesen, Melissa C.; Vermeulen, Roel; Shu, Xiao-Ou; Purdue, Mark P.; Stewart, Patricia A.; Xiang, Yong-Bing; Chow, Wong-Ho; Zheng, Tongzhang; Ji, Bu-Tian; Yang, Gong; Linet, Martha S.; Hu, Wei; Zhang, Heping; Zheng, Wei; Gao, Yu-Tang; Rothman, Nathaniel; Lan, Qing

    2015-01-01

    Background The association between benzene exposure and non-Hodgkin lymphoma (NHL) has been the subject of debate as a result of inconsistent epidemiologic evidence. An International Agency for Research on Cancer (IARC) working group evaluated benzene in 2009 and noted evidence for a positive association between benzene exposure and NHL risk. Objective We evaluated the association between occupational benzene exposure and NHL among 73,087 women enrolled in the prospective population-based Shanghai Women’s Health Study. Methods Benzene exposure estimates were derived using a previously developed exposure assessment framework that combined ordinal job-exposure matrix intensity ratings with quantitative benzene exposure measurements from an inspection database of Shanghai factories collected between 1954 and 2000. Associations between benzene exposure metrics and NHL (n = 102 cases) were assessed using Cox proportional hazard models, with study follow-up occurring from December 1996 through December 2009. Results Women ever exposed to benzene had a significantly higher risk of NHL [hazard ratio (HR) = 1.87, 95% CI: 1.19, 2.96]. Compared with unexposed women, significant trends in NHL risk were observed for increasing years of benzene exposure (ptrend = 0.006) and increasing cumulative exposure levels (ptrend = 0.005), with the highest duration and cumulative exposure tertiles having a significantly higher association with NHL (HR = 2.07, 95% CI: 1.07, 4.01 and HR = 2.16, 95% CI: 1.17, 3.98, respectively). Conclusions Our findings, using a population-based prospective cohort of women with diverse occupational histories, provide additional evidence that occupational exposure to benzene is associated with NHL risk. Citation Bassig BA, Friesen MC, Vermeulen R, Shu XO, Purdue MP, Stewart PA, Xiang YB, Chow WH, Zheng T, Ji BT, Yang G, Linet MS, Hu W, Zhang H, Zheng W, Gao YT, Rothman N, Lan Q. 2015. Occupational exposure to benzene and non-Hodgkin lymphoma in a population

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

    International Nuclear Information System (INIS)

    Sabourin, P.J.; Sun, J.D.; MacGregor, J.T.; Wehr, C.M.; Birnbaum, L.S.; Lucier, G.; Henderson, R.F.

    1990-01-01

    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

  9. Validation of Armadillo officinalis Dumèril, 1816 (Crustacea, Isopoda, Oniscidea) as a bioindicator: in vivo study of air benzene exposure.

    Science.gov (United States)

    Agodi, A; Oliveri Conti, G; Barchitta, M; Quattrocchi, A; Lombardo, B M; Montesanto, G; Messina, G; Fiore, M; Ferrante, M

    2015-04-01

    This study tests the potential for using Armadillo officinalis as a bioindicator of exposure to and activation of benzene metabolic pathways using an in vivo model. A. officinalis specimens collected in a natural reserve were divided into a control and three test groups exposed to 2.00, 5.32 or 9.09 µg/m(3) benzene for 24h. Three independent tests were performed to assess model reproducibility. Animals were dissected to obtain three pooled tissue samples per group: hepatopancreas (HEP), other organs and tissues (OOT), and exoskeleton (EXO). Muconic acid (MA), S-phenylmercapturic acid (S-PMA), two human metabolites of benzene, and changes in mtDNA copy number, a human biomarker of benzene exposure, were determined in each sample; benzene was determined only in EXO. MA was measured by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection, S-PMA by triple quadrupole mass spectrometer liquid chromatography with electro spray ionization (LC-MS-ESI-TQD), mtDNA by real-time quantitative PCR and end-point PCR, and benzene by quadrupole mass spectrometer head-space gas chromatography (HSGC-MS). MA and S-PMA levels rose both in HEP and OOT; EXO exhibited increasing benzene concentrations; and mtDNA copy number rose in HEP but not in OOT samples. Overall, our findings demonstrate that A. officinalis is a sensitive bioindicator of air benzene exposure and show for the first time its ability to reproduce human metabolic dynamics. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. 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.

  11. Solvatochromic effect studies on the absorption spectra of 4-((2-ethylphenyl)diazenyl)benzene-1,3-diol and 2-((2-ethylphenyl)diazenyl)benzene-1,3,5-triol molecules

    Energy Technology Data Exchange (ETDEWEB)

    Guelseven, Yadigar; Tasal, Erol; Sidir, Isa [Department of Physics, Faculty of Arts and Sciences, Eskisehir Osmangazi University, Eskisehir 26480 (Turkey); Guengoer, Tayyar [Department of Physics, Faculty of Arts and Sciences, Akdeniz University, Antalya (Turkey); Berber, Halil [Department of Chemistry, Faculty of Sciences, Anadolu University, Eskisehir (Turkey); Oegretir, Cemil [Department of Chemistry, Faculty of Arts and Sciences, Eskisehir Osmangazi University, Eskisehir (Turkey)

    2009-06-15

    The electronic absorption spectra of 4-((2-ethylphenyl)diazenyl)benzene-1,3-diol and 2-((2-ethylphenyl)diazenyl)benzene-1,3,5-triol molecules in the nine different solvent variable electronic characters have been recorded. The solvent dependent maximum absorption band ({pi}-{pi}* transitions) shifts, {nu}{sub max}, were analyzed using a wide range of parameters such as refractive index, dielectric constant and Kamlet-Taft parameters [hydrogen bond donating ability ({alpha}) and hydrogen bond accepting ability ({beta})]. The electronic transitions are assigned and the solvent-induced spectral shifts have been analyzed in relation to the different solute-solvent interaction mechanism using computational chemistry. The intermolecular interaction types in the azobenzene derivatives solutions have been established on the basis of a multiple linear regression analysis. The fitting coefficients obtained from this analysis allowed us to estimate the contribution of each type of interactions to the total spectral shifts in the studied solutions. (author)

  12. CCDC 932109: Experimental Crystal Structure Determination : catena-[(mu~6~-benzene-1,3,5-tricarboxylato)-(mu~4~-benzene-1,3,5-tricarboxylato)-tetrapyridine-di-copper-di-nickel

    KAUST Repository

    Gao, Junkuo

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  13. CCDC 932108: Experimental Crystal Structure Determination : catena-[(mu~6~-benzene-1,3,5-tricarboxylato)-(mu~4~-benzene-1,3,5-tricarboxylato)-tetrapyridine-di-copper-di-cobalt

    KAUST Repository

    Gao, Junkuo

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  14. Acetyl-l-carnitine partially prevents benzene-induced hematotoxicity and oxidative stress in C3H/He mice.

    Science.gov (United States)

    Sun, Rongli; Zhang, Juan; Wei, Haiyan; Meng, Xing; Ding, Qin; Sun, Fengxia; Cao, Meng; Yin, Lihong; Pu, Yuepu

    2017-04-01

    Benzene is an environmental pollutant and occupational toxicant which induces hematotoxicity. Our previous metabonomics study suggested that acetyl-l-carnitine (ALCAR) decreased in the mouse plasma and bone marrow (BM) cells due to benzene exposure. In the present study, the topic on whether ALCAR influences hematotoxicity caused by benzene exposure was explored. Thirty-two male C3H/He mice were divided into four groups: control group (C: vehicle, oil), benzene group (150mg/kg body weight (b.w.) benzene), benzene+A1 group (150mg/kg b.w. benzene+100mg/kg b.w. ALCAR), and benzene+A2 group (150mg/kg b.w. benzene+200mg/kg b.w. ALCAR). Benzene was injected subcutaneously, and ALCAR was orally administrated via gavage once daily for 4 weeks consecutively. After the experimental period, the blood routine, BM cell number and frequency of hematopoietic stem/progenitor cell (HS/PC) were assessed. The mitochondrial membrane potential and ATP level were determined to evaluate the mitochondrial function. Reactive oxygen species (ROS), hydrogen peroxide (H 2 O 2 ) and malondialdehyde (MDA) levels were also examined, and the comet assay was performed to measure oxidative stress. Results showed that ALCAR intervention can partially reduce the benzene-induced damage on BM and HS/PCs and can simultaneously alleviate the DNA damage by reducing benzene-induced H 2 O 2, ROS, and MDA. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. 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.

  16. Furan-based benzene mono- and dicarboxylic acid derivatives as multiple inhibitors of the bacterial Mur ligases (MurC-MurF): experimental and computational characterization

    Science.gov (United States)

    Perdih, Andrej; Hrast, Martina; Pureber, Kaja; Barreteau, Hélène; Grdadolnik, Simona Golič; Kocjan, Darko; Gobec, Stanislav; Solmajer, Tom; Wolber, Gerhard

    2015-06-01

    Bacterial resistance to the available antibiotic agents underlines an urgent need for the discovery of novel antibacterial agents. Members of the bacterial Mur ligase family MurC-MurF involved in the intracellular stages of the bacterial peptidoglycan biosynthesis have recently emerged as a collection of attractive targets for novel antibacterial drug design. In this study, we have first extended the knowledge of the class of furan-based benzene-1,3-dicarboxylic acid derivatives by first showing a multiple MurC-MurF ligase inhibition for representatives of the extended series of this class. Steady-state kinetics studies on the MurD enzyme were performed for compound 1, suggesting a competitive inhibition with respect to ATP. To the best of our knowledge, compound 1 represents the first ATP-competitive MurD inhibitor reported to date with concurrent multiple inhibition of all four Mur ligases (MurC-MurF). Subsequent molecular dynamic (MD) simulations coupled with interaction energy calculations were performed for two alternative in silico models of compound 1 in the UMA/ d-Glu- and ATP-binding sites of MurD, identifying binding in the ATP-binding site as energetically more favorable in comparison to the UMA/ d-Glu-binding site, which was in agreement with steady-state kinetic data. In the final stage, based on the obtained MD data novel furan-based benzene monocarboxylic acid derivatives 8- 11, exhibiting multiple Mur ligase (MurC-MurF) inhibition with predominantly superior ligase inhibition over the original series, were discovered and for compound 10 it was shown to possess promising antibacterial activity against S. aureus. These compounds represent novel leads that could by further optimization pave the way to novel antibacterial agents.

  17. 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

  18. Biomarkers of susceptibility following benzene exposure: influence of genetic polymorphisms on benzene metabolism and health effects.

    Science.gov (United States)

    Carbonari, Damiano; Chiarella, Pieranna; Mansi, Antonella; Pigini, Daniela; Iavicoli, Sergio; Tranfo, Giovanna

    2016-01-01

    Benzene is a ubiquitous occupational and environmental pollutant. Improved industrial hygiene allowed airborne concentrations close to the environmental context (1-1000 µg/m(3)). Conversely, new limits for benzene levels in urban air were set (5 µg/m(3)). The biomonitoring of exposure to such low benzene concentrations are performed measuring specific and sensitive biomarkers such as S-phenylmercapturic acid, trans, trans-muconic acid and urinary benzene: many studies referred high variability in the levels of these biomarkers, suggesting the involvement of polymorphic metabolic genes in the individual susceptibility to benzene toxicity. We reviewed the influence of metabolic polymorphisms on the biomarkers levels of benzene exposure and effect, in order to understand the real impact of benzene exposure on subjects with increased susceptibility.

  19. Structural and vibrational study of a neurotransmitter molecule: Dopamine [4-(2-aminoethyl) benzene-1,2-diol

    Science.gov (United States)

    Jha, Omkant; Yadav, T. K.; Yadav, R. A.

    2018-01-01

    Structural and vibrational studies for the most stable conformer of dopamine {4-(2-Aminoethyl) benzene-1, 2-diol} have been carried out at the DFT/B3LYP/6-311 ++G** level using the Gaussian 09 software. The IR and Raman spectra have been recorded and analyzed in light of the computed vibrational parameters using the DFT and the PEDs computed with the help of the GAR2PED software. Some of the fundamentals have considerably changed frequencies in going from benzene to dopamine. Except the rocking and wagging modes of the NH2 group the other four modes are pure group modes. The rocking and wagging modes of the NH2 group show mixing with the other modes. The two Osbnd H stretching vibrations are highly localized modes. The Kekule phenyl ring stretching mode is found to remain almost unchanged. The HOMO-LUMO study suggests the existence of charge transfer within the molecule and the energy gap supports the pharmacological active property of the dopamine molecule. The NBO analysis has been carried out to understand the proper and improper hydrogen bonding.

  20. Evaluating Occupational Exposure to Carcinogenic Volatile Organic Compounds in an Oil-Dependent Chemical Industry: a Case Study on Benzen and Epichlorohydrin

    Directory of Open Access Journals (Sweden)

    Amir Reza Negahban

    2014-04-01

    Full Text Available Background & Objectives: Exposure of workers to carcinogenic compounds in chemical industries during a long period might cause irreversible health effects. This study evaluated workers exposure to benzene and epichlorohydrin in breathing air in one of the oil-dependent chemical industries of Iran. Methods: This descriptive-analytic study was performed in one of the oil-dependent chemical industries of south of Iran, winter, 2012. A total of 173 workers were examined in this study. NIOSH 1501 and 1010 methods were used to assess personal exposure to benzene and epichlorohydrin, correspondingly. Collected samples were analyzed with gas chromatography-mass spectrophotometry method. Results: Among 346 collected samples, benzene was identified in all cases (100% and epichlorohydrin in 156 samples (45%. A significant difference was found in the mean of exposure to benzene and epichlorohydrin in various workshops (Pvalue 0.05. Conclusion: It seems that work nature of employees in chemical industry affects their exposure to volatile organic compounds in workplace. According to the results, due to the proximity of compounds concentration to the action level, especially benzene and also the workers exposure to less than the maximum limit in the long-term, reducing exposure through appropriate control measures are necessary.

  1. [The study on behaviour of protective equipment utilization of workers exposed to benzene and factors based on Planned Behavior Theory].

    Science.gov (United States)

    Huang, J Y; Liu, C D; Zhang, W M; Fu, Y K; Ma, H Y

    2018-02-20

    Objective: To investigate and predict the behavioral intention and mode of the protective equipment utilization selection of the workers who used Benzene, the Theory of Planned Behavior (TPB) was applied to establish the behavioral model to enhance the theoretical foundation for long-term intervention. Methods: Questionnaires were used to survey the 707 workers, and all the behaviors of using protective equipment were investigated. Evaluate the relationships between each variable and obtain the influence affects by structural equation model. Results: The investigation showed that 38.47% of the total workers (272 cases) used whole body protection, 13.58% used partially, and 16.69% didn't use any body protection. There were significant difference between the varying degrees in the four dimensions (behavioral attitude, perceived behavior control, subjective norm, and behavioral intention) (Pbehavior control was the most important influencing factor, subjective norm, positive attitude, negative attitude were the other three respects in sequence. The path co-efficient were 0.600、0.215、0.141 and 0.046 respectively. Conclusion: The study show that the theory of planned behavior can effectively explain the behavioral intention and behavior of protective equipment utilization. Therefore, combining the subjective initiative of individuals with the supervision of enterprises, In order to effectively enhance the protective equipment utilization of benzene workers.

  2. Theoretical studies on the structures and detonation properties of nitramine explosives containing benzene ring.

    Science.gov (United States)

    Zhao, GuoZheng; Lu, Ming

    2012-06-01

    The nitramine compounds containing benzene ring were optimized to obtain their molecular geometries and electronic structures at DFT-B3LYP/6-31+G(d) level. The theoretical molecular density (ρ), heat of formation (HOF), energy gap (ΔE(LUMO-HOMO)), charge on the nitro group (-Q(NO2)), detonation velocity (D) and detonation pressure (P), estimated using Kamlet-Jacobs equations, showed that the detonation properties of these compounds were excellent. It is found that there are good linear relationships between density, heat of formation, detonation velocity, detonation pressure and the number of nitro group. The simulation results reveal that molecule G performs similarly to famous explosive HMX, and molecule H outperforms HMX. According to the quantitative standard of energetics as an HEDC (high energy density compound), molecule H essentially satisfies this requirement. These results provide basic information for molecular design of novel high energetic density compounds.

  3. The electronic structure of the isoelectronic, square-planar complexes [FeII(L)2]2- and [CoIII(L Bu)2]- (L2- and (L Bu)2-=benzene-1,2-dithiolates): an experimental and density functional theoretical study.

    Science.gov (United States)

    Ray, Kallol; Begum, Ameerunisha; Weyhermüller, Thomas; Piligkos, Stergios; van Slageren, Joris; Neese, Frank; Wieghardt, Karl

    2005-03-30

    The electronic structures of two formally isoelectronic transition-metal dithiolato complexes [Fe(L)2]2- (1) and [Co(L Bu)2]1- (2) both possessing a spin triplet ground state (St=1) have been investigated by various spectroscopic and density functional methods; H2L Bu represents the pro-ligand 3,5-di-tert-butylbenzene-1,2-dithiol and H2L is the corresponding unsubstituted benzene-1,2-dithiol. An axial zero-field splitting (D) of +32 cm(-1) for 2 has been measured independently by SQUID magnetometry, far-infrared absorption, and variable-temperature and variable-field (VTVH) magnetic circular dichroism spectroscopies. A similar D value of +28 cm(-1) is obtained for 1 on the basis of VTVH SQUID measurements. The absorption spectra of 1 and 2 are found, however, to be very different. Complex 1 is light yellow in color with no intense transition in the visible region, whereas 2 is deep blue. DFT calculations establish that the electronic structures of the [Fe(L)2](2-) and [Co(L)2]1- anions are very different and explain the observed differences in their absorption spectra. On the basis of these spectroscopic and theoretical analyses, 1 is best described as containing an intermediate spin FeII ion, whereas for the corresponding cobalt complex, oxidation states describing a d6 (CoIII) or d7 (CoII) electron configuration cannot be unambiguously assigned. The physical origin of the large zero-field splitting in both 1 and 2 is found to be due to the presence of low-energy spin-conserved d-d excitations which lead to a large Dzz through efficient spin-orbit coupling. Differential covalency effects appear to be of limited importance for this property.

  4. Investigating the effects of in utero benzene exposure on epigenetic modifications in maternal and fetal CD-1 mice

    International Nuclear Information System (INIS)

    Philbrook, Nicola A.; Winn, Louise M.

    2015-01-01

    Exposure to the ubiquitous environmental pollutant benzene is positively correlated with leukemia in adults and may be associated with childhood leukemia following in utero exposure. While numerous studies implicate oxidative stress and DNA damage as playing a role in benzene-mediated carcinogenicity, emerging evidence suggests that alterations in epigenetic regulations may be involved. The present study aimed to determine whether DNA methylation and/or various histone modifications were altered following in utero benzene exposure in CD-1 mice. Global DNA methylation and promoter-specific methylation of the tumor suppressor gene, p15, were assessed. Additionally, levels of acetylated histones H3, H4, and H3K56, as well as methylated histones H3K9 and H3K27 were assessed by Western blotting. A significant decrease in global DNA methylation of maternal bone marrow was observed following benzene exposure; however no effect on global DNA methylation was detected in fetal livers. Additionally, no effect of benzene exposure was observed on p15 promoter methylation or any measured histone modifications in both maternal bone marrow and fetal livers. These results suggest that the methodology used in the present study did not reveal alterations in DNA methylation and histone modifications following in utero exposure to benzene; however further experimentation investigating these modifications at the whole genome/epigenome level, as well as at later stages of benzene-induced carcinogenesis, are warranted. - Highlights: • Benzene exposure in pregnant mice decreased global DNA methylation in maternal bone marrow. • Benzene exposure in pregnant mice had no effect on global DNA methylation in fetal livers. • No effect of benzene exposure was observed on p15 promoter methylation. • No effect of benzene on measured histone modifications in both maternal bone marrow and fetal livers was observed.

  5. Benzene: questions and answers

    International Nuclear Information System (INIS)

    1999-01-01

    This information booklet is intended to inform residents near natural gas dehydration facilities about benzene and its levels in the atmosphere. It was issued following the federal government's decision to place benzene on its Priority Substances List and to require industry to establish means for reducing benzene emissions from natural gas dehydrators and to inform residents about benzene emissions from glycol dehydration facilities. Accordingly, the booklet explains what benzene is (a colourless flammable liquid component of hydrocarbons) how it gets into the air (during gasoline refining, vehicle refueling and the production of steel and petrochemicals), the associated health hazards (a recognized carcinogen, causing an increased incidence of leukemia in concentrations of 100 parts per million), defines a glycol dehydrator (a facility built at or near some natural gas fields for the removal of water from the natural gas to prevent corrosion and freezing of pipelines), and enumerates the steps that are being taken to reduce benzene levels in the air (benzene levels in gasoline have been reduced, along with benzene emissions from petrochemical plants, refineries, steel plants and glycol dehydrators by 54 per cent to date; this will rise to 90 per cent by 2005). In addition to these actions, industry plans call for all existing glycol dehydrators within 750 metres of any permanent residence to be limited to benzene emissions of no more than three tonnes per year before 2001; new glycol dehydrators after that date will be expected to have benzene emissions reduced to the lowest level that can be practically achieved

  6. Benzene derivatives produced by Fusarium graminearum - Short communication.

    Science.gov (United States)

    Ntushelo, Khayalethu; Setshedi, Itumeleng

    2015-06-01

    Using NMR spectroscopy benzene derivatives were detected in mycelia of Fusarium graminearum, a pathogen of wheat and maize. In previous studies F. graminearum was found to cause cancer to humans and benzene derivatives were detected in breath of cancer sufferers. Surprisingly, no study found benzene derivatives to be the cancerous agents in F. graminearum. In this study we detected benzene derivatives in F. graminearum and propose to study their role as cancer agents.

  7. Synthesis and Thermal-Stability Study of Polybutylene Itaconate Modified with Divinyl Benzene and Glycerol

    Directory of Open Access Journals (Sweden)

    Atmanto Heru Wibowo

    2014-10-01

    Full Text Available Polybutylene itaconate (PBI for modification with divinyl benzene (DVB and glycerol has been synthesized at 180 °C for 3 h via polycondensation of itaconic acid (IA and butanediols using catalyst of Ti(OBu4. Modification on PBI was done with addition of 15%, 20% and 25% DVB (w/w using benzoyl peroxide. With glycerol, weight variations of glycerol:1,4-butanediol (BDO in the synthesis were 10%, 30%, and 50% (mole/mole. PBI and PBI modified with DVB and glycerol were characterized with FTIR and TG-DTA. PBI showed a wavenumber shift from 1703 cm-1 to 1728 cm-1 of the C=O functional group from acid to esther. The DVB modification on PBI also showed that the intensity decrease of C=C stretching was due to the formation of crosslinking on the double bond. In the modification with glycerol, three dimensional networking on the polyester occurred through bonding between hydroxyl of glycerol and acid group of IA. Constant intensity of C=C stretching on polyester was seen. The thermal stability of PBI modified with DVB increased, accompanied by rigidity change of the structure. The thermal stability of PBI modified with glycerol decreased, caused by the decrease of regularity degree and the elasticity increase of the three dimensional structure of polyester.

  8. A review of the data quality and comparability of case-control studies of low-level exposure to benzene in the petroleum industry

    NARCIS (Netherlands)

    Miller, B.G.; Fransman, W.; Heederik, D.; Hurley, J.F.; Kromhout, H.; Fitzsimons, E.

    2010-01-01

    Purpose Published case–control studies of risks of leukaemia following low exposures to benzene in the distribution of petroleum (gasoline) have not all identiWed the same level of risk, but the studies have had diVerences in cohort inclusion, case determination and availability of occupational and

  9. A review of the data quality and comparability of case-control studies of low-level exposure to benzene in the petroleum industry.

    NARCIS (Netherlands)

    Miller, B.G.; Fransman, W.|info:eu-repo/dai/nl/314000461; Heederik, D.|info:eu-repo/dai/nl/072910542; Hurley, J.F.; Kromhout, H.|info:eu-repo/dai/nl/074385224; Fitzsimons, E.

    2010-01-01

    PURPOSE: Published case-control studies of risks of leukaemia following low exposures to benzene in the distribution of petroleum (gasoline) have not all identified the same level of risk, but the studies have had differences in cohort inclusion, case determination and availability of occupational

  10. Benzene degradation in a denitrifying biofilm reactor

    NARCIS (Netherlands)

    Waals, van der Marcelle J.; Atashgahi, Siavash; Rocha, da Ulisses Nunes; Zaan, van der Bas M.; Smidt, Hauke; Gerritse, Jan

    2017-01-01

    Benzene is an aromatic compound and harmful for the environment. Biodegradation of benzene can reduce the toxicological risk after accidental or controlled release of this chemical in the environment. In this study, we further characterized an anaerobic continuous biofilm culture grown for more

  11. Anaerobic Benzene Oxidation by Geobacter Species

    Science.gov (United States)

    Bain, Timothy S.; Nevin, Kelly P.; Barlett, Melissa A.; Lovley, Derek R.

    2012-01-01

    The abundance of Geobacter species in contaminated aquifers in which benzene is anaerobically degraded has led to the suggestion that some Geobacter species might be capable of anaerobic benzene degradation, but this has never been documented. A strain of Geobacter, designated strain Ben, was isolated from sediments from the Fe(III)-reducing zone of a petroleum-contaminated aquifer in which there was significant capacity for anaerobic benzene oxidation. Strain Ben grew in a medium with benzene as the sole electron donor and Fe(III) oxide as the sole electron acceptor. Furthermore, additional evaluation of Geobacter metallireducens demonstrated that it could also grow in benzene-Fe(III) medium. In both strain Ben and G. metallireducens the stoichiometry of benzene metabolism and Fe(III) reduction was consistent with the oxidation of benzene to carbon dioxide with Fe(III) serving as the sole electron acceptor. With benzene as the electron donor, and Fe(III) oxide (strain Ben) or Fe(III) citrate (G. metallireducens) as the electron acceptor, the cell yields of strain Ben and G. metallireducens were 3.2 × 109 and 8.4 × 109 cells/mmol of Fe(III) reduced, respectively. Strain Ben also oxidized benzene with anthraquinone-2,6-disulfonate (AQDS) as the sole electron acceptor with cell yields of 5.9 × 109 cells/mmol of AQDS reduced. Strain Ben serves as model organism for the study of anaerobic benzene metabolism in petroleum-contaminated aquifers, and G. metallireducens is the first anaerobic benzene-degrading organism that can be genetically manipulated. PMID:23001648

  12. 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 usi...

  13. Occupational exposure to benzene in South Korea.

    Science.gov (United States)

    Kang, Seong-Kyu; Lee, Mi-Young; Kim, Tae-Kyun; Lee, Jeong-Oh; Ahn, Yeon Soon

    2005-05-30

    Benzene has been used in various industries as glues or solvents in Korea. Since 1981, a preparation containing more than 1% benzene is not allowed to be manufactured, used or dealt with in the workplace, except in laboratories and in those situations benzene must be used in a completely sealed process as specified in Industrial Safety and Health Act (ISHA). Claims for compensation of hematopoietic diseases related to benzene have been rising even though the work environment has been improved. This study was conducted to assess the status of benzene exposure in different industries in Korea. We reviewed the claimed cases investigated by the Korea Occupational Safety and Health Agency (KOSHA) between 1992 and 2000. The Survey of National Work Environment Status in 1998 was analyzed to assume the number of workers and factories exposed to benzene. In 2000, six factories were investigated to evaluate benzene exposure. Personal air monitoring was performed in 61 workers and urine samples were collected from 57 workers to measure trans,trans-muconic acid (t,t-MA). Hematologic examination has performed. Thirty-four cases of hematopoietic diseases were investigated by KOSHA including eight cases of myelodysplastic syndrome and eight cases of acute myelocytic leukemia. Eight cases were accepted as related to benzene exposure. The number of workers possibly exposed to benzene can be estimated to be 196,182 workers from 6219 factories based on the database. The geometric mean of benzene in air was 0.094 (0.005-5.311) ppm. Seven samples were higher than 1 ppm but they did not go over the 10 ppm occupational exposure limit (OEL) value in Korea. The geometric mean of trans,trans-muconic acid in urine was 0.966 (0.24-2.74) mg/g creatinine. The benzene exposure level was low except in a factory where benzene was used to polymerize other chemicals. The ambient benzene from 0.1 to 1 ppm was significantly correlated with urine t,t-MA concentration (r=0.733, p<0.01). Hematologic

  14. Aromaticity of benzene in condensed phases. A case of a benzene-water system

    Science.gov (United States)

    Zborowski, Krzysztof K.

    2014-05-01

    A theoretical Density Functional Theory study was performed for a benzene molecule in water cages. Two DFT functionals (B3LYP and BLYP) were employed. The optimized geometries of the studied clusters were used to calculate the aromaticity of benzene in a condensed phase using the aromaticity indices: HOMA, NICS, PDI, and H. The results were compared with aromaticity of a single benzene molecule in the gas phase and in the solvent environment provided by the PCM continuum model. It is argued that high aromaticity of benzene in the gas phase is retained in the water environment.

  15. 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

  16. Experimental studies o

    Directory of Open Access Journals (Sweden)

    Mohammad Mohsen Sarafraz

    2014-06-01

    Full Text Available Experimental investigations on the influences of different contaminants to deionized water have been conducted under the sub-cooled flow boiling heat transfer inside the vertical annulus. Many experiments have been performed to investigate the influence of different operating parameters on the flow boiling heat transfer coefficient in the upward flow of contaminated water under the atmospheric pressure. The experimental apparatus provides the particular conditions to investigate the influence of heat flux (up to 132 kW/m2, flow rate (1.5–3.5 l/min, sub-cooling level (Max. 30 °C, and concentration of contaminants (1–5% by volume. According to the results, with increasing the heat flux and flow rate, the flow boiling heat transfer coefficient and rate of bubble formation significantly increase. Results also demonstrated that adding contaminants to the deionized water causes the flow boiling heat transfer coefficient to be deteriorated. Likewise, sub-cooling level may only influence on the onset of nucleate boiling and heat flux corresponding to beginning of nucleate boiling phenomenon which is called inception heat flux.

  17. Story of skeletally substituted benzenes

    Indian Academy of Sciences (India)

    Unknown

    corresponds to the out-of-plane distortion of the hydrogen atom connected to the heteroatoms, which is then ..... etc. exhibits significant localization.24 The skeletally substituted benzenes considered in the study with a wide ... involving cationic and anionic systems are expected to show considerable localization. In. Table 3.

  18. Benzene and its Isomers

    Indian Academy of Sciences (India)

    instantly brings benzene to mind. Benzene is one of the most basic structural units of thousands of the so-called aromatic compounds, which include dyes, drugs, polymers and many more types of compounds that are very useful for our existence and progress. The whole gamut of the chemistry of aromatic compounds, ...

  19. Benzene and its Isomers

    Indian Academy of Sciences (India)

    present vast knowledge of extremely complex structures of thou- sands of organic compounds, the structure of benzene now appears ridiculously simple, but it had taken nearly half a century of effort by some of the greatest ever scientists to arrive at it correctly. Benzene was discovered by Michael Faraday in the year 1825 ...

  20. Variability of cytometric parameters in various clusters of interstitial endocrine cells of testicles in CBA × C57Bl6 mice during experimental chrome-benzene intoxication.

    Science.gov (United States)

    Bokov, D A; Shevlyuk, N N; Abdil'danova, A M

    2014-05-01

    Chromium-benzene intoxication was associated with not only damage to tissue elements of the testicles, but also realization of the adaptive mechanisms protecting endocrine active structures in male CBA × C57Bl6 mice. Quantitative substantiation of the transformation processes, their direction, relationships, and attained levels were obtained.

  1. 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 of the GC...

  2. Benzene and lymphohematopoietic malignancies in humans.

    Science.gov (United States)

    Hayes, R B; Songnian, Y; Dosemeci, M; Linet, M

    2001-08-01

    Quantitative evaluations of benzene-associated risk for cancer have relied primarily on findings from a cohort study of highly exposed U.S. rubber workers. An epidemiologic investigation in China (NCI/CAPM study) extended quantitative evaluations of cancer risk to a broader range of benzene exposures, particularly at lower levels. We review the evidence implicating benzene in the etiology of hematopoietic disorders, clarify methodologic aspects of the NCI/CAPM study, and examine the study in the context of the broader literature on health effects associated with occupational benzene exposure. Quantitative relationships for cancer risk from China and the U.S. show a relatively smooth increase in risk for acute myeloid leukemia and related conditions over a broad dose range of benzene exposure (below 200 ppm-years mostly from the China study and above 200 ppm-years mostly from the U.S. study). Risks of acute myeloid leukemia and other malignant and nonmalignant hematopoietic disorders associated with benzene exposure in China are consistent with other information about benzene exposure, hematotoxicity, and cancer risk, extending evidence for hematopoietic cancer risks to levels substantially lower than had previously been established. Published 2001 Wiley-Liss, Inc.

  3. Thermal C–H-Bond Activation of Benzene with Cationic [Pt(CX3)(L)]+ Complexes in the Gas Phase: A Experimental/Theoretical Study (X = H, D; L = 1,10-Phenanthroline, 2,2’-Bipyrimidine, 2,2’-Bipyridine, and (o,o’-Cl2C6H3)N=C(CH3)–C(CH3)=N(o,o’-Cl2C6H3))

    Czech Academy of Sciences Publication Activity Database

    Butschke, B.; Schröder, Detlef; Schwarz, H.

    2009-01-01

    Roč. 28, č. 15 (2009), s. 4340-4349 ISSN 0276-7333 Institutional research plan: CEZ:AV0Z40550506 Keywords : benzene * C-H activation * mass spectrometry * nitrogen ligands * platinum Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.204, year: 2009

  4. CCDC 1056509: Experimental Crystal Structure Determination : dodecakis(mu5-Benzene-1,3-dithiolato)-tetrakis(triphenylphosphine)-nonacosa-silver N,N-dimethylformamide solvate

    KAUST Repository

    AbdulHalim, Lina G.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  5. CCDC 1006896: Experimental Crystal Structure Determination : 1,3,5-tris(4-(2,4-Diamino-1,3,5-triazin-6-yl)phenyl)benzene unknown solvate

    KAUST Repository

    Li, Peng

    2014-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  6. CCDC 1050931: Experimental Crystal Structure Determination : phenyl-(N,N'-(pyridine-2,6-diyl)-bis(P,P-di-t-butyl(phosphinous amide)))-rhodium benzene solvate

    KAUST Repository

    Wang, Yuan

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  7. CCDC 1044642: Experimental Crystal Structure Determination : catena-[(mu-5-[(pyridin-4-ylcarbonyl)amino]benzene-1,3-dicarboxylato)-copper unknown solvate

    KAUST Repository

    Chen, Zhijie

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  8. CCDC 866711: Experimental Crystal Structure Determination : catena-((mu~12~-5,5',5''-(Benzene-1,3,5-triyltris(methyleneoxy))-tri-isophthalato)-hexa-aqua-hexa-copper)

    KAUST Repository

    Eubank, J.F.

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  9. An experimental study

    Directory of Open Access Journals (Sweden)

    Zohreh Zare

    2017-12-01

    Full Text Available Background: Oocyte developmental competence is one of the key factors for determining the success rate of assisted reproductive technique. Objective: The aim of the current study was to investigate the effect of L-carnitine (LC supplementation during in vitro maturation (IVM, on preimplantation embryo development and expression of genes involved in embryo competence derived from oocytes selected with brilliant cresyl blue (BCB test. Materials and Methods: Cumulus-oocyte complexes (COCs were obtained from NMRI mice ovaries. COCs were stained with BCB and then BCB+ (colored cytoplasm oocytes cultured in IVM medium supplemented with 0.3 or 0.6 mg/ml LC. COCs untreated with LC were used as control. Fertilization rate and blastocyst development rate were determined after in vitro fertilization. In addition, quantitative reverse transcriptase polymerase chain reaction was used to measure relative genes expression related with development (Ccnb1, Mos, Ces5, and Dppa2 and apoptosis (Bax and Bcl-xL in oocytes and embryos. Results: Oocytes treated with both LC concentrations showed higher blastocyst development rate compared with untreated oocytes (p<0.01. Moreover, fertilization rate was increased in oocytes treated with 0.6 mg/ml LC (p<0.01. Treatment of oocytes with both LC concentrations increased (p<0.01 the level of Ccnb1 mRNA in MII oocytes. The two-cell stage embryos and blastocysts derived from LC-treated oocytes (0.6 mg/ml showed increased the expression levels of Dppa2 and Bcl-xl mRNA, respectively (p<0.01. Conclusion: The results of the present study show that adding of LC to the IVM medium of BCB+ oocytes can ameliorate reproductive success following in vitro fertilization.

  10. Benzene from Traffic

    DEFF Research Database (Denmark)

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

    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...... in petrol from 1998 and the increasing number of vehicles with catalysts will probably lead to compliance with this limit value...

  11. Dielectric properties of liquid systems: study of interactions in the systems carbon tetrachloride with benzene, toluene, and p-xylene

    Directory of Open Access Journals (Sweden)

    Adrián H. Buep

    2014-12-01

    Full Text Available Intermolecular associations in liquid systems of non-polar and slightly polar compounds were studied through excess molar volumes (VEM and excess dielectric properties (εE and n2ED for mixtures of carbon tetrachloride (CCl4 with benzene (C6H6, toluene (C6H5CH3, and p-xylene (p-(CH32C6H4. These excess properties were calculated from measurements of density (ρ, static permittivity (ε, and refractive index (nD over the whole range of concentrations at 298.15 K. The values of the excess dielectric properties for these mixtures were fitted in two different ways, one through least squares using the Redlich–Kister equation and the other using a model developed to explain deviations from ideality. The first fit was found to be descriptive while the second gave the equilibrium constant values for the interaction products actually formed in the mixtures and the respective electronic polarizabilities and dipole moments, indicating the existence of interaction products.

  12. 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

    2006-01-01

    on the 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...... 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....... Furthermore, H2S is observed not to interact strongly with these sites. The present results have also provided insight into the nitrogen compound inhibition of the direct desulturization DDS pathway. The difference in the poisoning by benzene and pyridine is observed to be related to the ease with which...

  13. Natural Attenuation and Anaerobic Benzene Detoxification Processes at a Chlorobenzene-Contaminated Industrial Site Inferred from Field Investigations and Microcosm Studies.

    Science.gov (United States)

    Qiao, Wenjing; Luo, Fei; Lomheim, Line; Mack, Elizabeth Erin; Ye, Shujun; Wu, Jichun; Edwards, Elizabeth A

    2018-01-02

    A five-year site investigation was conducted at a former chemical plant in Nanjing, China. The main contaminants were 1,2,4-trichlorobenzene (TCB) reaching concentrations up to 7300 μg/L, dichlorobenzene (DCB) isomers, monochlorobenzene (MCB), and benzene. Over time, these contaminants naturally attenuated to below regulatory levels under anaerobic conditions. To confirm the transformation processes and to explore the mechanisms, a corresponding laboratory microcosm study was completed demonstrating that 1,2,4-TCB was dechlorinated to 1,2-DCB, 1,3-DCB, and 1,4-DCB in approximately 2%/10%/88% molar proportions. The DCB isomers were dechlorinated via MCB to benzene, and, finally, benzene was degraded under prevailing sulfate-reducing conditions. Dechlorination could not be attributed to known dechlorinators Dehalobacter or Dehalococcoides, while anaerobic benzene degradation was mediated by microbes affiliated to a Deltaproteobacterium ORM2, previously associated with this activity. Unidentified organic compounds, possibly aromatic compounds related to past on-site production processes, were fueling the dechlorination reactions in situ. The microcosm study confirmed transformation processes inferred from field data and provided needed assurance for natural attenuation. Activity-based microcosm studies are often omitted from site characterization in favor of rapid and less expensive molecular surveys. However, the value of microcosm studies for confirming transformation processes, establishing electron balances, assessing cocontaminant inhibition, and validating appropriate monitoring tools is clear. At complex sites impacted by multiple compounds with poorly characterized transformation mechanisms, activity assays provide valuable data to incorporate into the conceptual site model to most effectively inform remediation alternatives.

  14. Does maternal exposure to benzene and PM10 during pregnancy increase the risk of congenital anomalies? A population-based case-control study

    Science.gov (United States)

    Vinceti, Marco; Malagoli, Carlotta; Malavolti, Marcella; Cherubini, Andrea; Maffeis, Giuseppe; Rodolfi, Rossella; Heck, Julia E.; Astolfi, Gianni; Calzolari, Elisa; Nicolini, Fausto

    2015-01-01

    A few studies have suggested an association between maternal exposure to ambient air pollution from vehicular traffic and risk of congenital anomalies in the offspring, but epidemiologic evidence is neither strong nor entirely consistent. In a population-based case-control study in a Northern Italy community encompassing 228 cases of birth defects and 228 referent newborns, we investigated if maternal exposure to PM10 and benzene from vehicular traffic during early pregnancy, as estimated through a dispersion model, was associated with excess teratogenic risk. In conditional logistic regression analysis, and with adjustment for the other pollutant, we found that higher exposure to PM10 but not benzene was associated with increased risk of birth defects overall. Anomaly categories showing the strongest dose-response relation with PM10 exposure were musculoskeletal and chromosomal abnormalities but not cardiovascular defects, with Down syndrome being among the specific abnormalities showing the strongest association, though risk estimates particularly for the less frequent defects were statistically very unstable. Further adjustment in the regression model for potential confounders did not considerably alter the results. All the associations were stronger for average levels of PM10 than for their maximal level. Findings of this study give some support for an excess teratogenic risk following maternal exposure during pregnancy to PM10, but not benzene. Such association appears to be limited to some birth defect categories. PMID:26410719

  15. Benzene formation in Titan's lower atmosphere

    Science.gov (United States)

    Plane, J. M. C.; Douglas, K.; Blitz, M. A.; Heard, D. E.; Seakins, P. W.; Feng, W.; Willacy, K.

    2017-09-01

    The most distinctive feature of Saturn's moon Titan is that it is covered in a thick haze. The haze consists of organic particles called tholins, of which benzene is thought to be an important precursor. Here we examine two pathways to form benzene. The first involves reactions on cosmic dust particles, which mostly do not ablate when entering Titan's atmosphere and accumulate in the lower atmosphere. We have shown in the laboratory that acetylene molecules stick on synthetic cosmic dust at low temperatures, and react efficiently to make benzene. The second pathway is through gas phase reactions involving radical species formed through methane photochemistry. A new lab study shows that the rates of critical reactions involving these radicals vary unexpectedly at low temperatures, leading to significant changes in important benzene precursors.

  16. How carbo-benzenes fit molecules in their inner core as do biologic ion carriers?

    KAUST Repository

    Turias, Francesc

    2015-09-25

    The present computational study complements experimental efforts to describe and characterize carbo-benzene derivatives as paradigms of aromatic carbo-mers. A long-lasting issue has been the possibility of the π-electron crown of the C18 carbo-benzene ring to fit metals or any chemical agents in its core. A systematic screening of candidate inclusion complexes was carried out by density functional theory calculations. Mayer bond order, aromaticity indices, and energy decomposition analyses complete the understanding of the strength of the host-guest interaction. The change in steric and electronic properties induced by the guest agent is investigated by means of steric maps. Substitution of H atoms at the carbo-benzene periphery by electron-withdrawing or electron-donating groups is shown to have a determining influence on the stability of the inclusion complex ions: while electronegative substituents enhance the recognition of cations, electropositive substituents do the same for anions. The results confirm the experimental failure hitherto to evidence a carbo-benzene complex. Nevertheless, the affinity of carbo-benzene for the potassium cation appears promising for the design of planar hydrocarbon analogues of biologic ion carriers. © 2015 Springer Science+Business Media New York.

  17. Study of CeO₂ Modified AlNi Mixed Pillared Clays Supported Palladium Catalysts for Benzene Adsorption/Desorption-Catalytic Combustion.

    Science.gov (United States)

    Li, Jingrong; Zuo, Shufeng; Yang, Peng; Qi, Chenze

    2017-08-15

    A new functional AlNi-pillared clays (AlNi-PILC) with a large surface area and pore volume was synthesized. The performance of adsorption/desorption-catalytic combustion over CeO 2- modified Pd/AlNi-PILC catalysts was also studied. The results showed that the d 001 -value and specific surface area ( S BET ) of AlNi-PILC reached 2.11 nm and 374.8 m²/g, respectively. The large S BET and the d 001 -value improved the high capacity for benzene adsorption. Also, the strong interaction between PdCe mixed oxides and AlNi-PILC led to the high dispersion of PdO and CeO₂ on the support, which was responsible for the high catalytic performance. Especially, 0.2% Pd/12.5% Ce/AlNi-PILC presented high performance for benzene combustion at 240 °C and high CO₂ selectivity. Also, the combustion temperatures were lower compared to the desorption temperatures, which demonstrated that it could accomplish benzene combustion during the desorption process. Furthermore, its activity did not decrease after continuous reaction for 1000 h in dry air, and it also displayed good resistance to water and the chlorinated compound, making it a promising catalytic material for the elimination of volatile organic compounds.

  18. The adsorption of Benzene-Ethylene Dichloride Mixtures on Activated Carbon

    Science.gov (United States)

    Miao, T.; Tang, H. M.; Cheng, Z. X.

    2018-02-01

    The single component adsorption of benzene and ethylene dichloride and also the adsorption of binary mixtures of benzene and ethylene dichloride have been studied in a small fixed isothermal bed containing activated carbon (AC). Results indicate that an empirical Langmuir isotherm fits the experimental data for single components. An extended form of the empirical Langmuir isotherm, in which the parameters are obtained from single component data, satisfactorily describes the adsorption of binary mixtures. Breakthrough curves of both components could be predicted with good precision studied. This paper analyses the adsorption behaviour of a mixture of VOCs (benzene–ethylene dichloride) on AC, due to the lack of information regarding the adsorption of mixtures.

  19. Adsorption of Benzene by “Green” functionalization of Montmorillonite

    Directory of Open Access Journals (Sweden)

    Anjum Hirra

    2018-01-01

    Full Text Available The capacity of organically modified Montmorillonite (MMT clay to adsorb nonpolar organic compound (benzene in an aqueous solution, was investigated under the batch process. MMT was pretreated (centrifuged and then functionalized with green intercalating agent i.e. 1-hexyl-3-methyl imadazolium chloride [HMim][Cl]. The characterization through Fourir Transoform Infrared Spectroscopy (FTIR, Differential Scanning Calorimeter (DSC and Field Emission Scanning Electron Microscope (FE-SEM confirmed the presence of the oxygen containing functional groups, changes in melting point and variation in the morphological properties. The governing parameters for the sorption of benzene such as the effect of contact time, pH, adsorbent dose and rotation were studied. The kinetic data conformed to pseuodo 2nd order kinetic model and the isotherm experimental data were a better fit to Langmuir model with maximum adsorption capacity of 588.23mg/g under experimental conditions. Overall, MMT intercalated with 1-hexyl-3-methyl imadazolium chloride is a promising environmental friendly adsorbent for the abatement of benzene in an aqueous solution.

  20. Tokamak experimental power reactor studies

    International Nuclear Information System (INIS)

    1975-06-01

    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.)

  1. Benzene and superior counterpart; Benzene et homologues superieurs

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    A century ago, the first case of purpura and acute anemia provoked by benzene was described. Afterwards, others important toxic effects in relation with the exposure to this solvent were known: medullar aplasia, acute leukemia,carcinogenesis. The chronic intoxication by benzene is called benzenism, the term of benzolism is devoted to the intoxication provoked by the mixture of benzene and superior counterparts: toluene, xylenes. (N.C.)

  2. Reactions of iron atoms with benzene.

    Science.gov (United States)

    Parker, Stewart F

    2010-02-04

    The reaction of iron atoms with benzene has been studied for nearly 40 years. Despite this, there is no agreement as to the nature of the products. With the aid of density functional theory calculations of the energetics and the infrared spectra of the various species, the present work provides a rationalization of the conflicting reports regarding the nature of the products of the reaction of iron atoms with benzene in low-temperature matrices. At low temperature in dilute benzene matrices, Fe(eta(6)-C(6)H(6)) and Fe(eta(6)-C(6)H(6))(2) are the major products. At high iron concentrations, Fe(2)(eta(2)-C(6)H(6)) is also formed. In pure benzene at low temperature, Fe(eta(6)-C(6)H(6))(2) and Fe(eta(6)-C(6)H(6))(eta(4)-C(6)H(6)) are formed. None of the species undergo photoexcitation to give insertion products HFe(C(6)H(5)). In pure benzene at 77 K, Fe(eta(6)-C(6)H(6))(eta(4)-C(6)H(6)) is the major product, together with small amounts of Fe(eta(6)-C(6)H(6))(2) and iron clusters. The infrared spectra of pure benzene are complicated by the activation of infrared forbidden modes by the presence of the metal atom.

  3. Studies on Photochemical Reactions of Air Pollutants. IX. Formation of o-Nitrophenol and p-Nitrophenol by Reaction of Benzene Oxide with NO2 in Air

    OpenAIRE

    野島, 一宏; 大谷, 武司; 菅野, 三郎; 広部, 雅昭

    1982-01-01

    When benzene oxide was brought into contact with nitrogen dioxide in air, o-nitro-phenol and p-nitrophenol were formed together with fog. Benzene oxide seems to be an intermediate in the photochemical reaction of benzene with nitrogen dioxide in air.

  4. Benzene patterns in different urban environments and a prediction model for benzene rates based on NOx values

    Science.gov (United States)

    Paz, Shlomit; Goldstein, Pavel; Kordova-Biezuner, Levana; Adler, Lea

    2017-04-01

    Exposure to benzene has been associated with multiple severe impacts on health. This notwithstanding, at most monitoring stations, benzene is not monitored on a regular basis. The aims of the study were to compare benzene rates in different urban environments (region with heavy traffic and industrial region), to analyse the relationship between benzene and meteorological parameters in a Mediterranean climate type, to estimate the linkages between benzene and NOx and to suggest a prediction model for benzene rates based on NOx levels in order contribute to a better estimation of benzene. Data were used from two different monitoring stations, located on the eastern Mediterranean coast: 1) a traffic monitoring station in Tel Aviv, Israel (TLV) located in an urban region with heavy traffic; 2) a general air quality monitoring station in Haifa Bay (HIB), located in Israel's main industrial region. At each station, hourly, daily, monthly, seasonal, and annual data of benzene, NOx, mean temperature, relative humidity, inversion level, and temperature gradient were analysed over three years: 2008, 2009, and 2010. A prediction model for benzene rates based on NOx levels (which are monitored regularly) was developed to contribute to a better estimation of benzene. The severity of benzene pollution was found to be considerably higher at the traffic monitoring station (TLV) than at the general air quality station (HIB), despite the location of the latter in an industrial area. Hourly, daily, monthly, seasonal, and annual patterns have been shown to coincide with anthropogenic activities (traffic), the day of the week, and atmospheric conditions. A strong correlation between NOx and benzene allowed the development of a prediction model for benzene rates, based on NOx, the day of the week, and the month. The model succeeded in predicting the benzene values throughout the year (except for September). The severity of benzene pollution was found to be considerably higher at the

  5. 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

    2016-10-02

    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.

  6. Study of polar and nonpolar substituted benzenes and aromatic isomers on carbon-coated zirconia and alkyl bonded phases.

    Science.gov (United States)

    Jackson, Paul T; Carr, Peter W

    2002-06-07

    Retention factors of polar and non-polar mono- and di-substituted benzene derivatives were measured on carbon coated zirconia (C/ZrO2) and an alkyl modified silica using water-acetonitrile mobile phases. Published data on porous graphitic carbon phases (PGC) were used to facilitate comparisons between the two types of carbon media. This work showed that retention on both C/ZrO2 and PGC is much more sensitive to the solute polarizability, dipolarity, and shape than on aliphatic phases. For simple disubstituted benzenes there was no general clear cut advantage in terms of chromatographic selectivity to using a carbon-based phase over a bonded phase silica; however, the selectivities towards such isomers are quite different on the two types of media. In contradistinction to their effect on alkyl bonded phase retention, addition of a dipolar substituent and weak hydrogen bond acceptor to a benzene ring almost always increases the solute's retention on C/ZrO2 and PGC.

  7. EXPERIMENTAL STUDY IN NATURAL CONVECTION

    African Journals Online (AJOL)

    PROF. BARTH EKWEME

    The study of thermal and ventilation parameters, obtained in a transient, laminar solar chimney of reduced dimensions, (1 < m <3) m with a square collector (side = 2m) is presented. Experimental measurements has been made to determine the temperature of the absorber and the fluid in the collector, it is shown that at the ...

  8. Anaerobic benzene degradation by bacteria

    OpenAIRE

    Vogt, Carsten; Kleinsteuber, Sabine; Richnow, Hans‐Hermann

    2011-01-01

    Summary Benzene is a widespread and toxic contaminant. The fate of benzene in contaminated aquifers seems to be primarily controlled by the abundance of oxygen: benzene is aerobically degraded at high rates by ubiquitous microorganisms, and the oxygen‐dependent pathways for its breakdown were elucidated more than 50 years ago. In contrast, benzene was thought to be persistent under anoxic conditions until 25 years ago. Nevertheless, within the last 15 years, several benzene‐degrading cultures...

  9. Separation of benzene from alkanes using 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid at several temperatures and atmospheric pressure: Effect of the size of the aliphatic hydrocarbons

    International Nuclear Information System (INIS)

    Gonzalez, Emilio J.; Calvar, Noelia; Gomez, Elena; Dominguez, Angeles

    2010-01-01

    The ionic liquid 1-ethyl-3-methylpyridinium ethylsulfate, [EMpy][ESO 4 ], was studied for the separation of benzene from aliphatic hydrocarbons (octane or nonane) by solvent extraction through the determination of the (liquid + liquid) equilibrium (LLE) of the ternary systems: {octane (1) + benzene (2) + [EMpy][ESO 4 ] (3)} and {nonane (1) + benzene (2) + [EMpy][ESO 4 ] (3)} at T = (283.15 and 298.15) K and atmospheric pressure. Binodal curves were determined using the 'cloud point' method, and tie-line compositions were obtained by density measurements. The values of selectivity and distribution coefficient, derived from the tie-line data, were used to decide if this ionic liquid can be used as potential solvent for the separation of benzene from aliphatic hydrocarbons using liquid extraction. These results were analyzed and compared to those previously reported for the systems {hexane + benzene + [EMpy][ESO 4 ]} and {heptane + benzene + [EMpy][ESO 4 ]}. The experimental results show that this ionic liquid is suitable for the extraction of benzene from mixtures containing octane and nonane. The consistency of tie-line data was ascertained by applying the Othmer-Tobias and Hand equations. The experimental results for the ternary systems were well correlated with the NRTL model. No literature data were found for the mixtures discussed in this paper.

  10. Anaerobic benzene degradation by bacteria.

    Science.gov (United States)

    Vogt, Carsten; Kleinsteuber, Sabine; Richnow, Hans-Hermann

    2011-11-01

    Benzene is a widespread and toxic contaminant. The fate of benzene in contaminated aquifers seems to be primarily controlled by the abundance of oxygen: benzene is aerobically degraded at high rates by ubiquitous microorganisms, and the oxygen-dependent pathways for its breakdown were elucidated more than 50 years ago. In contrast, benzene was thought to be persistent under anoxic conditions until 25 years ago. Nevertheless, within the last 15 years, several benzene-degrading cultures have been enriched under varying electron acceptor conditions in laboratories around the world, and organisms involved in anaerobic benzene degradation have been identified, indicating that anaerobic benzene degradation is a relevant environmental process. However, only a few benzene degraders have been isolated in pure culture so far, and they all use nitrate as an electron acceptor. In some highly enriched strictly anaerobic cultures, benzene has been described to be mineralized cooperatively by two or more different organisms. Despite great efforts, the biochemical mechanism by which the aromatic ring of benzene is activated in the absence of oxygen is still not fully elucidated; methylation, hydroxylation and carboxylation are discussed as likely reactions. This review summarizes the current knowledge about the 'key players' of anaerobic benzene degradation under different electron acceptor conditions and the possible pathway(s) of anaerobic benzene degradation. © 2011 The Authors; Journal compilation © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  11. Benzene and its Isomers

    Indian Academy of Sciences (India)

    part of an assignment given by a gas company. The gas obtained by thermal decomposition of whale oil used to be stored in cylinders under pressure for illuminating streetlights. Faraday succeeded in isolating benzene by distillation and crystalliza- tion of the light mobile oil left behind in the gas cylinders. He was also able ...

  12. Benzene and its Isomers

    Indian Academy of Sciences (India)

    Benzene and its Isomers atomic weights and availability of improved analytical methods. At this time the .... geometry. Forcing them in cyclic structures would lead to signifi- cant strain. Bicyclic structures do not easily accommodate double bonds at bridgehead positions (Bredt's rule). Many of the polycy- clic isomers clearly ...

  13. On Benzene and Aromaticity

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 4. On Benzene and Aromaticity History and Some Folklore. M V Bhatt. General Article Volume 3 Issue 4 April 1998 pp 88-93. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/003/04/0088-0093 ...

  14. Benzene and its Isomers

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 5. Benzene and its Isomers - How many Structures can we Draw for C6H6? Gopalpur Nagendrappa. General Article Volume 6 Issue 5 May 2001 pp 74-78. Fulltext. Click here to view fulltext PDF. Permanent link:

  15. Survey the Efficiency of Catalytic Ozonation Process with Carbosieve in the Removal of Benzene from Polluted Air Stream

    Directory of Open Access Journals (Sweden)

    M. Samarghandi

    2014-01-01

    Full Text Available Introduction & Objective: Benzene is one of the most common volatile organic compounds in the indoor and outdoor environments that has always been considered as one of the causes of air pollution. Thus before being discharged to the environment, it must be treated from pol-luted air stream. The aim of this study was to determine the efficiency of catalytic ozonation process with carbosieve in the removal of benzene from polluted air stream. Materials & Methods: The study was experimental in which catalytic ozonation process with carbosieve was used in the removal of benzene from polluted air stream. The experiments were carried out in a reactor with continuous system and the results of catalytic ozonation were compared with the results of single ozonation and carbosieve adsorbent .The sampling, benzene analyzing and determining of ozone concentration in samples were done with 1501 NMAM method by GC equipped with FID detector and iodometry , respectively. Results: The results of this study showed that the removal effectiveness of single ozonation process is averagely less than 19%. Also the efficiency of absorbent decreased with the con-centration increase of benzene.The increase ratio of efficiency in catalytic ozonation process to efficiency of carbosieve adsorbent was averagely 45%. Conclusion: With regard to high efficiency of catalytic ozonation process and increasing the benzene removal , the catalytic ozonation process is suggested as a promising and alternative technology for elimination of VOCs from the polluted air stream. (Sci J Hamadan Univ Med Sci 2014; 20 (4:303-311

  16. Benzene and childhood acute leukemia in Oklahoma.

    Science.gov (United States)

    Janitz, Amanda E; Campbell, Janis E; Magzamen, Sheryl; Pate, Anne; Stoner, Julie A; Peck, Jennifer D

    2017-10-01

    Although childhood cancer is a leading cause of childhood mortality in the US, evidence regarding the etiology is lacking. The goal of this study was to evaluate the association between benzene, a known carcinogen, and childhood acute leukemia. We conducted a case-control study including cases diagnosed with acute leukemia between 1997 and 2012 (n = 307) from the Oklahoma Central Cancer Registry and controls matched on week of birth from birth certificates (n = 1013). We used conditional logistic regression to evaluate the association between benzene, measured with the 2005 National-Scale Air Toxics Assessment (NATA) at census tract of the birth residence, and childhood acute leukemia. We observed no differences in benzene exposure overall between cases and controls. However, when stratified by year of birth, cases born from 2005 to 2010 had a three-fold increased unadjusted odds of elevated exposure compared to controls born in this same time period (4th Quartile OR: 3.53, 95% CI: 1.35, 9.27). Furthermore, the estimates for children with acute myeloid leukemia (AML) were stronger than those with acute lymphoid leukemia, though not statistically significant. While we did not observe an association between benzene and childhood leukemia overall, our results suggest that acute leukemia is associated with increased benzene exposure among more recent births, and children with AML may have increased benzene exposure at birth. Using the NATA estimates allowed us to assess a specific pollutant at the census tract level, providing an advantage over monitor or point source data. Our study, however, cannot rule out the possibility that benzene may be a marker of other traffic-related exposures and temporal misclassification may explain the lack of an association among earlier births. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Extraction of benzene and cyclohexane using [BMIM][N(CN)2] and their equilibrium modeling

    Science.gov (United States)

    Ismail, Marhaina; Bustam, M. Azmi; Man, Zakaria

    2017-12-01

    The separation of aromatic compound from aliphatic mixture is one of the essential industrial processes for an economically green process. In order to determine the separation efficiency of ionic liquid (IL) as a solvent in the separation, the ternary diagram of liquid-liquid extraction (LLE) 1-butyl-3-methylimidazolium dicyanamide [BMIM][N(CN)2] with benzene and cyclohexane was studied at T=298.15 K and atmospheric pressure. The solute distribution coefficient and solvent selectivity derived from the equilibrium data were used to evaluate if the selected ionic liquid can be considered as potential solvent for the separation of benzene from cyclohexane. The experimental tie line data was correlated using non-random two liquid model (NRTL) and Margules model. It was found that the solute distribution coefficient is (0.4430-0.0776) and selectivity of [BMIM][N(CN)2] for benzene is (53.6-13.9). The ternary diagram showed that the selected IL can perform the separation of benzene and cyclohexane as it has extractive capacity and selectivity. Therefore, [BMIM][N(CN)2] can be considered as a potential extracting solvent for the LLE of benzene and cyclohexane.

  18. Benzene and its Health Effects

    Directory of Open Access Journals (Sweden)

    Mustafa Tozun

    2008-12-01

    Full Text Available Benzene is an aromatic hydrocarbon, colorless, sweet-smelling liquid. It is an important industrial solvent, is used in the manufacture of plastics, detergents, pesticides, and other chemicals. Benzene is a carcinogen. Short-term and high level benzene exposure causes symptoms of the central nervous system. Long-term benzene exposure may affect to bone marrow and blood production. Additionally, genotoxic, immunological, and urogenital negative effects may occur with chronicle benzene exposure. [TAF Prev Med Bull 2008; 7(6.000: 541-546

  19. Benzene monitoring at CPPI service stations

    International Nuclear Information System (INIS)

    Davis, C.S.

    1996-01-01

    A study was conducted in which ambient airborne concentration levels of benzene were measured at a representative set of gasoline service stations in Toronto and Vancouver. Benzene is considered to be toxic under the Canadian Environmental Protection Act (CEPA). It is a component in gasoline (0.1 to 4.7 per cent by volume) and is present in vehicle evaporative and exhaust emissions. Measurements were made every 18 days at each station for one year. The objective of the study was to assess the ambient and employee exposure levels of benzene at service stations and to determine whether the levels were typical of those published in the literature. In a 1986 PACE (Petroleum Association for Conservation of the Canadian Environment) survey of exposure to gasoline hydrocarbon vapours at Canadian service stations, airborne benzene concentration data was inconsistent with similar ambient and personal exposure data in the international literature. It was concluded that both the mean ambient benzene concentration and the personal exposure level measurements in this study were generally lower than similar measurements made in other countries. The same observation was made with respect to ambient and personal exposure levels measured in this study vis-a-vis those measured during the PACE study conducted in 1985/86. . 31 refs., 24 tabs., 5 figs

  20. 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)

  1. In vitro study of DNA adduct 8-OHDG formation from 2'-deoxyguanosine-5'-monophosphate with benzene through Fenton reaction

    Science.gov (United States)

    Budiawan, Erlindah, R.; Handayani, S.; Dani, I. C.

    2017-07-01

    Carcinogenic compounds from air pollution such as benzene could tend to generate free radicals and lead to DNA-radicals interaction producing 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a biomarker of oxidative DNA damage. This research was conducted by reacting DNA base 2'-deoxyguanosine-5'-monophosphate (dGMP) with benzene in the variation of temperature 37 °C and 60 °C, variation of pH 7.4 and 8.4 during 5 hours of incubation time, and in the variation of Fe(II) and H2O2 as reagent of Fenton reaction. The result of adduct was analyzed by using HPLC reversed phase with UV detector at a wavelength 254 nm. In this research, the retention time of dGMP standard was measured at 7.3 minutes and 8-OHdG was measured at 9.0 minutes. The formation of 8-OHdG from dGMP and benzene interaction in addition of Fe(II) at pH 8.4 and temperature 60 °C were higher than their interaction in the condition of pH 7.4 and temperature 37 °C. The presence of hydrogen peroxide under incubation condition at pH 8.4 and at temperature 60 °C can trigger the higher formation of 8-OHdG compared to the incubation condition at pH 7.4 and temperature 37 °C.

  2. Anaerobic benzene degradation by bacteria

    Science.gov (United States)

    Vogt, Carsten; Kleinsteuber, Sabine; Richnow, Hans‐Hermann

    2011-01-01

    Summary Benzene is a widespread and toxic contaminant. The fate of benzene in contaminated aquifers seems to be primarily controlled by the abundance of oxygen: benzene is aerobically degraded at high rates by ubiquitous microorganisms, and the oxygen‐dependent pathways for its breakdown were elucidated more than 50 years ago. In contrast, benzene was thought to be persistent under anoxic conditions until 25 years ago. Nevertheless, within the last 15 years, several benzene‐degrading cultures have been enriched under varying electron acceptor conditions in laboratories around the world, and organisms involved in anaerobic benzene degradation have been identified, indicating that anaerobic benzene degradation is a relevant environmental process. However, only a few benzene degraders have been isolated in pure culture so far, and they all use nitrate as an electron acceptor. In some highly enriched strictly anaerobic cultures, benzene has been described to be mineralized cooperatively by two or more different organisms. Despite great efforts, the biochemical mechanism by which the aromatic ring of benzene is activated in the absence of oxygen is still not fully elucidated; methylation, hydroxylation and carboxylation are discussed as likely reactions. This review summarizes the current knowledge about the ‘key players’ of anaerobic benzene degradation under different electron acceptor conditions and the possible pathway(s) of anaerobic benzene degradation. PMID:21450012

  3. A review of the data quality and comparability of case-control studies of low-level exposure to benzene in the petroleum industry.

    Science.gov (United States)

    Miller, B G; Fransman, W; Heederik, D; Hurley, J F; Kromhout, H; Fitzsimons, E

    2010-01-01

    Published case-control studies of risks of leukaemia following low exposures to benzene in the distribution of petroleum (gasoline) have not all identified the same level of risk, but the studies have had differences in cohort inclusion, case determination and availability of occupational and lifestyle data. We reviewed the quality and comparability of the data from three (of four) studies. Through site visits, discussions with the investigators and reading study reports, we reviewed and audited the methods used for selecting cases and controls, for estimating individual exposures and for analysing and interpreting the data. Case-control comparisons of exposures were examined using customized graphs. We found that there were no issues of subject selection, methods or general data quality that were likely to have distorted their internal comparisons; we could not check in detail whether the metric for exposure assessments was the same across the studies; the exposure assessments for the Australian study required the least backward estimation, and the Canadian, which also had fewest cases, the most; evidence of an increased risk at higher exposures in Australia was convincing. The findings are consistent with some effect of benzene at higher lifetime exposures. A proposed pooled analysis should improve quantification of any exposure-response relationship.

  4. Local radiolytic effectiveness of Auger electrons of iodine-125 in benzene-iodine solutions

    International Nuclear Information System (INIS)

    Uenak, P.; Uenak, T.

    1987-01-01

    High radiotoxicity of iodine-125 has been mainly attributed to the local radiolytic effects of Auger electrons on biological systems. In the present study, experimental and theoretical results are compared. The agreement between the experimental and theoretical results explains that the energy absorption of iodine aggregates has an important role in the radiolytic effectiveness of Auger electrons and iodine-125 in benzene-iodine solutions. (author) 18 refs.; 3 figs

  5. Uptake of aromatic hydrocarbon vapors (benzene and phenanthrene) at the air-water interface of micron-size water droplets.

    Science.gov (United States)

    Raja, Suresh; Valsaraj, Kalliat T

    2004-12-01

    Uptake of aromatic hydrocarbon vapors (benzene and phenanthrene) by typical micrometer-sized fog-water droplets was studied using a falling droplet reactor at temperatures between 296 and 316 K. Uptake of phenanthrene vapor greater than that predicted by bulk (air-water)-phase equilibrium was observed for diameters less than 200 microm, and this was attributed to surface adsorption. The experimental values of the droplet-vapor partition constant were used to obtain the overall mass transfer coefficient and the mass accommodation coefficient for both benzene and phenanthrene. Mass transfer of phenanthrene was dependent only on gas-phase diffusion and mass accommodation at the interface. However, for benzene, the mass transfer was limited by liquid-phase diffusion and mass accommodation. A large value of the mass accommodation coefficient, alpha = (1.4 +/- 0.4) x 10(-2) was observed for the highly surface-active (hydrophobic) phenanthrene, whereas a small alpha = (9.7 +/- 1.8) x 10(-5) was observed for the less hydrophobic benzene. Critical cluster numbers ranging from 2 for benzene to 5.7 for phenanthrene were deduced using the critical cluster nucleation theory for mass accommodation. The enthalpy of mass accommodation was more negative for phenanthrene than it was for benzene. Consequently, the temperature effect was more pronounced for phenanthrene. A linear correlation was observed for the enthalpy of accommodation with the excess enthalpy of solution. A natural organic carbon surrogate (Suwannee Fulvic acid) in the water droplet increased the uptake for phenanthrene and benzene, the effect being more marked for phenanthrene. A characteristic time constant analysis showed that uptake and droplet scavenging would compete for the fog deposition of phenanthrene, whereas deposition would be unimpeded by the uptake rate for benzene vapor. For both compounds, the characteristic atmospheric reaction times were much larger and would not impact fog deposition.

  6. Ensuring comparability of benzene exposure estimates across three nested case-control studies in the petroleum industry in support of a pooled epidemiological analysis.

    Science.gov (United States)

    Glass, D C; Armstrong, T W; Pearlman, E D; Verma, D K; Schnatter, A R; Rushton, L

    2010-03-19

    Three case-control studies each nested within a cohort of petroleum workers assessed exposure to benzene in relation to risk of haematopoietic cancers. These studies have each been updated and the cases will be pooled to derive a more powerful study. The benzene exposure of new leukemia cases and controls was estimated in accordance with each respective study's original methods. An essential component of the process of pooling the data was comparison and rationalisation of the exposure estimates to ensure accuracy and consistency of approach. This paper describes this process and presents comparative estimates before and after appropriate revision took place. The original petroleum industry studies, in Canada, the UK and Australia, were conducted at different points in time by different study teams, but the industry used similar technology in similar eras in each of these countries. A job history for each subject giving job title, dates of starting and leaving the job and location of work, was assembled. For each job or task, the average benzene exposure (Base Estimate (BE) in ppm) was derived from measurements collected at applicable worksites. Estimates of exposure intensity (workplace exposure estimates (WE)) were then calculated for each line of work history by adjusting the BEs for site- and era-specific exposure-related variables such as loading technology and percentage benzene in the product. To ensure that the exposure estimates were comparable among the studies, the WEs were allocated to generic Job Categories, e.g. Tanker Driver (by technology used e.g. bottom loading), Motor Mechanic. The WEs were stratified into eras, reflecting technological changes in the industry. The arithmetic mean (AM), geometric mean (GM) and range of the stratified WEs were calculated, by study, for each generic Job Category. These were then compared. The AMs of the WEs were regarded as substantially similar if they were within 20% in all three studies in one era or for at

  7. Three Experimental Studies on Entrepreneurship

    DEFF Research Database (Denmark)

    Barirani, Ahmad

    Do entrepreneurs differ from others with regard to their behavioral traits, and can beliefs held by employers about these differences lead to self-employedworkers being stigmatized in the labor market? Although central to the study of entrepreneurship, the literature does not provide a clear answer...... on the premise that reliance on multiple methodological approaches can contribute to the credibility of empirical results, this thesis explores the above questions by resorting to experimental techniques. It first tests the hypothesis of whether entrepreneurs are more action-oriented than other occupational...

  8. Experimental study of neoclassical currents

    International Nuclear Information System (INIS)

    Zarnstorff, M.C.; Prager, S.C.

    1985-05-01

    A detailed experimental study is presented of the bootstrap and Pfirsch-Schlueter currents that are predicted by neoclassical transport theory. In a toroidal octupole, on magnetic surfaces within the separatrix, the observed parallel plasma currents are in excellent quantitative agreement with neoclassical theory with regard to the spatial structure (along a magnetic surface), collisionality dependence and toroidal magnetic field dependence. On magnetic surfaces outside the separatrix, the ion portion of the parallel current is in agreement with neoclassical theory but the electron parallel current is observed to obtain a unidirectional component which deviates from and exceeds the theoretical prediction

  9. Benzene and cyclohexane separation using 1-butyl-3-methylimidazolium thiocyanate

    Science.gov (United States)

    Gonfa, Girma; Ismail, Marhaina; Bustam, Mohamad Azmi

    2017-09-01

    Cyclohexane is mainly produced by catalytic hydrogenation of benzene. Removal of unreacted benzene from the product stream is very important in this process. However, due to their close boiling points and azeotrope formation, it is very difficult to separate cyclohexane and benzene by conventional distillation. Currently, special separation processes such as processes extractive distillation is commercially used for this separation. However, this extractive distillation suffers from process complexity and higher energy consumption due to their low extractive selectivity of molecular entrainers used. The aim of the present work is to investigate the applicability of ionic liquids as entrainer in extractive distillation of benzene and cyclohexane mixture. In this study, we investigated 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) ionic liquid for separation of benzene and cyclohexane by measuring the Vapor Liquid Equilibrium data of the two components in the presence of the ionic liquid. As green and potential environmentally friendly solvents, ionic liquids have attracted increasing attention as alternative conventional entrainers in extractive distillation. Isothermal Vapor Liquid Equilibrium for the benzene + cyclohexane + [BMIM][SCN] ternary system was obtained at 353.15 K using a Head Space Gas Chromatography. The addition of [BMIM][SCN] breaks the benzene-cyclohexane azeotrope and increased the relative volatility cyclohexane to benzene in the mixture. The effect of [BMIM][SCN] on the relative volatility cyclohexane to benzene was studied at various benzene and cyclohexane compositions and solvent to feed ratios. The performance of [BMIM][SCN] was compared with typical conventional solvents, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The results show that the relative volatility of cyclohexane to benzene in the presence of [BMIM][SCN] is higher compared that of DMSO and DMF.

  10. Biodegradation and kinetic study of benzene in bioreactor packed with PUF and alginate beads and immobilized with Bacillus sp. M3.

    Science.gov (United States)

    Kureel, M K; Geed, S R; Giri, B S; Rai, B N; Singh, R S

    2017-10-01

    Benzene removal in free and immobilized cells on polyurethane foam (PUF) and polyvinyl alcohol (PVA)-alginate beads was studied using an indigenous soil bacterium Bacillus sp. M3 isolated from petroleum-contaminated soil. The important process parameters (pH, temperature and inoculums size) were optimized and found to be 7, 37°C and 6.0×10 8 CFU/mL, respectively. Benzene removals were observed to be 70, 84 and 90% within 9days in a free cell, immobilized PVA-alginate beads and PUF, respectively under optimum operating conditions. FT-IR and GC-MS analysis confirm the presence of phenol, 1,2-benzenediol, hydroquinone and benzoate as metabolites. The important kinetic parameter ratios (µ max /K s ; L/mg·day ) calculated using Monod model was found to be 0.00123 for free cell, 0.00159 for immobilized alginate beads and 0.002016 for immobilized PUF. Similarly inhibition constants (K i ; mg/L) calculated using Andrew-Haldane model was found to be 435.84 for free cell, 664.25 for immobilized alginate beads and 724.93 for immobilized PUF. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Experimental studies of pneumococcal meningitis.

    Science.gov (United States)

    Brandt, Christian T

    2010-01-01

    This thesis summarizes experimental meningitis research conducted at Statens Serum Institut in collaboration with the Copenhagen HIV programme and the Danish Research Centre for Magnetic Resonance between 2001 and 2007. Previous experimental studies had shown that the host inflammatory response in invasive infections contributed significantly to an extremely poor outcome despite initiation of efficient antimicrobial chemotherapy. Consequently, we aimed to investigate and clarify how the course of disease in pneumococcal meningitis was modulated by local meningeal inflammation and concomitant systemic infection and inflammation. Experimental studies were based on the development of a rat model of pneumococcal meningitis, refined and optimized to closely resemble the human disease, mimicking disease severity, outcome, focal- and global brain injury and brain pathophysiology. These endpoints were evaluated by the development of a clinical score system, definition of outcomes and measurement of hearing loss by otoacoustic emission. The investigation of in-vitro and in-vivo brain pathology with histology and MRI revealed an injury pattern similar to that found clinically. Additionally, MRI enabled the study of parameters closely related to the cerebral pathophysiology of meningitis (brain oedema, blood brain barrier (BBB) permeability, focal brain injury and hydrocephalus). Modulation of the inflammatory host response was achieved by initiation of treatment prior to infection: 1) G-CSF treatment increased the peripheral availability of leukocytes, 2) Selectin blocker fucoidin attenuated meningeal leukocyte accumulation and 3) A serotype specific Ab augmented systemic pneumococcal phagocytosis. The studies revealed a dual role of the inflammatory response in pneumococcal meningitis. Whilst focal brain injury appeared to result from local meningeal infectious processes, clinical disease severity and outcome appeared determined by systemic infection. Furthermore systemic

  12. Mode-coupling study on the dynamics of hydrophobic hydration II: Aqueous solutions of benzene and rare gases.

    Science.gov (United States)

    Yamaguchi, T; Matsuoka, T; Koda, S

    2006-02-14

    The dynamic properties of both the solute and solvent of the aqueous solution of benzene, xenon and neon are calculated by the mode-coupling theory for molecular liquids based on the interaction-site model. The B-coefficients of the reorientational relaxation and the translational diffusion of the solvent are evaluated from their dependence on the concentration of the solute, and the reorientational relaxation time of water within the hydration shell is estimated based on the two-state model. The reorientational relaxation times of water in the bulk and within the hydration shell, that of solute, and the translational diffusion coefficients of solute and solvent, are calculated at 0-30 degrees C. The temperature dependence of these dynamic properties is in qualitative agreement with that of NMR experiment reported by Nakahara et al. (M. Nakahara, C. Wakai, Y. Yoshimoto and N. Matubayasi, J. Phys. Chem., 1996, 100, 1345-1349, ref. 36), although the agreement of the absolute values is not so good. The B-coefficients of the reorientational relaxation times for benzene, xenon and neon solution are correlated with the hydration number and the partial molar volume of the solute. The proportionality with the latter is better than that with the former. These results support the mechanism that the retardation of the mobility of water is caused by the cavity formation of the solute, as previously suggested by us (T. Yamaguchi, T. Matsuoka and S. Koda, J. Chem. Phys., 2004, 120, 7590-7601, ref. 34), rather than the conventional one that the rigid hydration structure formed around the hydrophobic solute reduces the mobility of water.

  13. A Comparative Study of Mn/Co Binary Metal Catalysts Supported on Two Commercial Diatomaceous Earths for Oxidation of Benzene

    Directory of Open Access Journals (Sweden)

    Marco Tomatis

    2018-03-01

    Full Text Available Two commercial diatomaceous earths were used as supports for the preparation of Mn/Co binary metal catalysts at different metal loads (5 to 10 wt % Mn and 5 to 15 wt % Co by incipient wetness deposition. The activity of the prepared catalysts towards the complete oxidation of benzene to CO2 and water was investigated between 100 and 400 °C. Raw supports and synthesized catalysts were characterized by XRD, N2 physisorption, SEM-EDS, H2-TPR, and TPD. The purification treatment of food-grade diatomite significantly affected the crystallinity of this support while reducing its specific surface area (SSA. A loss of SSA, associated with the increase in the metal load, was observed on samples prepared on natural diatomite, while the opposite trend occurred with food-grade diatomite-supported catalysts. Metal nanoparticles of around 50 nm diameter were observed on the catalysts’ surface by SEM analysis. EDS analysis confirmed the uniform deposition of the active phases on the support’s surface. A larger H2 consumption was found by TPR analysis of natural diatomite-based samples in comparison to those prepared at the same metal load on food-grade diatomite. During the catalytic oxidation experiment, over 90% conversion of benzene were achieved at a reaction temperature of 225 °C by all of the prepared samples. In addition, the formation of coke during the oxidation tests was demonstrated by TGA analysis and the soluble fraction of the produced coke was characterized by GC-MS.

  14. Nonthermal plasma assisted photocatalytic oxidation of dilute benzene

    Indian Academy of Sciences (India)

    to utilize the UV light for photocatalytic decomposition of chlorinated VOCs.23. Benzene, a commonly used industrial solvent, whose abatement under dilute concentrations (<1000 ppm) may not be economical by conventional techniques. The present study was aimed at the total oxidation of dilute benzene in a DBD reactor.

  15. Benzene exposures in urban areas

    International Nuclear Information System (INIS)

    Valerio, F.; Pala, M.; Cipolla, M.; Stella, A.

    2001-01-01

    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/m 3 , current European air quality guideline for this carcinogenic compound [it

  16. Experimental study of snow friction

    Science.gov (United States)

    Cohen, Caroline; Canale, Luca; Siria, Alessandro; Quere, David; Bocquet, Lyderic; Clanet, Christophe

    2017-11-01

    Snow friction results from the interplay of different physical processes: solid friction of granular material, phase change and lubrication, heat transport, capillarity, elasticity and plasticity. The multiple conditions of temperature, humidity and density of the snow result in different regimes of friction. In particular, there is an optimal amount of melted water to lubricate the contact between the ski sole and the snow grains. The thickness of the water layer depends on temperature, speed... A huge variety of waxes have been empirically developed to adapt the amount of water to the conditions of skiing, but remain mysterious. In these study, we investigate experimentally the mechanisms of snow friction at different scales: first, the friction of a ski on snow is measured on a test bench, depending on the snow characteristics and for different waxes. Then microscopic experiments are led in order to understand the friction at the ice crystals scale.

  17. 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.

  18. 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.

  19. Metagenomic and proteomic analyses to elucidate the mechanism of anaerobic benzene degradation

    Energy Technology Data Exchange (ETDEWEB)

    Abu Laban, Nidal [Helmholtz (Germany)

    2011-07-01

    This paper presents the mechanism of anaerobic benzene degradation using metagenomic and proteomic analyses. The objective of the study is to find out the microbes and biochemistry involved in benzene degradation. Hypotheses are proposed for the initial activation mechanism of benzene under anaerobic conditions. Two methods for degradation, molecular characterization and identification of benzene-degrading enzymes, are described. The physiological and molecular characteristics of iron-reducing enrichment culture are given and the process is detailed. Metagenome analysis of iron-reducing culture is presented using a pie chart. From the metagenome analysis of benzene-degrading culture, putative mobile element genes were identified in the aromatic-degrading configurations. Metaproteomic analysis of iron-reducing cultures and the anaerobic benzene degradation pathway are also elucidated. From the study, it can be concluded that gram-positive bacteria are involved in benzene degradation under iron-reducing conditions and that the catalysis mechanism of putative anaerobic benzene carboxylase needs further investigation.

  20. 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.

  1. 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

  2. Experimental study of virtual impactors

    International Nuclear Information System (INIS)

    Yule, T.J.; Broniarck, C.G.

    1979-01-01

    Virtual impactors are currently being used in a number of instruments to separate an aerosol into different size ranges. The virtual impactor is a variation of the standard impactor in which the impaction surface is replaced by an orifice into which particles can pass and be collected or counted. We have made an experimental study of the collection characteristics of virtual impactors. The parameters varied included: acceleration nozzle-to-collection probe distance, the ratio of the collection probe-to-acceleration nozzle diameters, and the ratio of collection probe-to-inlet flows. Measurements were also made with different collection probe geometries. It was found that it is possible to parameterize much of the data by introduction of the Stokes number and an effective minor flow collection efficiency. One disadvantage of the virtual impactor is that in the transition region particles are collected on the inside walls of the collection probe near the probe tip. The amount that is collected is a sensitive function of the probe geometry

  3. Substituent Effect in Benzene Dication

    NARCIS (Netherlands)

    Palusiak, M.; Domagala, M.; Dominikowska, J.E.; Bickelhaupt, F.M.

    2014-01-01

    It was recently postulated that the benzene ring and its 4n + 2 π-electron analogues are resistant to the substituent effect due to the fact that such systems tend to retain their delocalized character. Therefore, the 4n π-electron dicationic form of benzene should appear to be less resistant to the

  4. Influence of benzene emission from motorcycle on Bangkok air quality

    Science.gov (United States)

    Leong, Shing Tet; Muttamara, S.; Laortanakul, Preecha

    This study investigated the influence of benzene concentration from motorcycle exhaust emissions on ambient air quality in Bangkok Metropolitan Region (BMR). Measurement of benzene concentration in exhaust emissions is performed on a standard test driving cycle through which each motorcycle to be tested is driven. The test result revealed that average benzene concentrations in exhaust emission for the test motorcycles ranged from 3.02 to 109.68 mg/m 3. The finding also indicated that two-stroke motorcycles emitted five times more benzene than that of four-stroke motorcycles. Four air monitoring sites were strategically established to determine the relationship between average benzene concentrations with different traffic configurations in each traffic zone of BMR during peak/non-peak hours, day/night times and weekday/weekend. The shape of the curve for benzene level usually shows two peaks corresponding to the morning and evening traffic rush or commuter rush hours. The finding shows that the mean concentrations for benzene in all monitoring stations in the ambient air for peak hours (07:00-09:00 and 16:00-18:00 h) ranged from 15.1 to 42.4 μg/m 3. For non-peak hour (11:30-15:00 h), benzene levels were found in the range 16.3-30.9 μg/m 3. It is observed that higher levels of benzene are found among roadside stations with slow moving traffic while lower levels are found among roadside stations with fast traffic movement. Additional factors such as temperature, wind speed, rainfall, etc. are also considered in this study to determine the relationship between traffic conditions and ambient benzene levels.

  5. Benzene Oxidation Coupled to Sulfate Reduction

    OpenAIRE

    Lovley, D. R.; Coates, J. D.; Woodward, J. C.; Phillips, E.

    1995-01-01

    Highly reduced sediments from San Diego Bay, Calif., that were incubated under strictly anaerobic conditions metabolized benzene within 55 days when they were exposed initially to 1 (mu)M benzene. The rate of benzene metabolism increased as benzene was added back to the benzene-adapted sediments. When a [(sup14)C]benzene tracer was included with the benzene added to benzene-adapted sediments, 92% of the added radioactivity was recovered as (sup14)CO(inf2). Molybdate, an inhibitor of sulfate r...

  6. The tissue distribution and excretion study of paeoniflorin-6'-O-benzene sulfonate (CP-25) in rats.

    Science.gov (United States)

    Zhao, Mingyi; Zhou, Peng; Yu, Jun; James, Asenso; Xiao, Feng; Wang, Chun; Wei, Wei

    2018-03-09

    Paeoniflorin-6'-O-benzene sulfonate (code: CP-25) is a novel ester derivative of paeoniflorin (Pae). Compared to Pae, CP-25 has higher lipid solubility, bioavailability and better bioactivity. However, the tissue distribution and excretion of CP-25 still remain unknown. The LC-MS method was applied to investigate the tissue distribution and excretion of CP-25 in rats. As such, 50 mg/kg of CP-25 and Pae were administered to rats in multiple doses via an oral route. CP-25 and Pae were distributed widely and rapidly in all the tested tissues. Compared with Pae, the concentrations of CP-25 were almost increased evidently in most tissues. The highest CP-25 level was found in the liver (1476.33 ± 535.20 ng/g, male; 1970.38 ± 177.21 ng/g, female) at 3 h, and a high concentration of CP-25 was detected in male and female intestine, synovium, muscle, lung, and brain. Following a single oral dose of 50 mg/kg of CP-25 in rats, the total excretion of CP-25 was merely 21.8% (18.40, 3.19 and 0.22% for feces, bile and urine, respectively) in males; and was approximately 21.3% (14.04, 7.16 and 0.14% for feces, bile and urine, respectively) in females. The results indicated that the CP-25 concentration was higher in major tissues than Pae; CP-25 was primarily excreted through the feces; and there were gender-related differences in the tissue distribution and excretion.

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

    International Nuclear Information System (INIS)

    Geng, Chen; Yong, Chi; Chunpeng, Pan; Yan, Jian-hua; Ni, Ming-Jian

    2010-01-01

    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)

  8. Anaerobic Oxidation of Benzene by the Hyperthermophilic Archaeon Ferroglobus placidus▿†

    Science.gov (United States)

    Holmes, Dawn E.; Risso, Carla; Smith, Jessica A.; Lovley, Derek R.

    2011-01-01

    Anaerobic benzene oxidation coupled to the reduction of Fe(III) was studied in Ferroglobus placidus in order to learn more about how such a stable molecule could be metabolized under strict anaerobic conditions. F. placidus conserved energy to support growth at 85°C in a medium with benzene provided as the sole electron donor and Fe(III) as the sole electron acceptor. The stoichiometry of benzene loss and Fe(III) reduction, as well as the conversion of [14C]benzene to [14C]carbon dioxide, was consistent with complete oxidation of benzene to carbon dioxide with electron transfer to Fe(III). Benzoate, but not phenol or toluene, accumulated at low levels during benzene metabolism, and [14C]benzoate was produced from [14C]benzene. Analysis of gene transcript levels revealed increased expression of genes encoding enzymes for anaerobic benzoate degradation during growth on benzene versus growth on acetate, but genes involved in phenol degradation were not upregulated during growth on benzene. A gene for a putative carboxylase that was more highly expressed in benzene- than in benzoate-grown cells was identified. These results suggest that benzene is carboxylated to benzoate and that phenol is not an important intermediate in the benzene metabolism of F. placidus. This is the first demonstration of a microorganism in pure culture that can grow on benzene under strict anaerobic conditions and for which there is strong evidence for degradation of benzene via clearly defined anaerobic metabolic pathways. Thus, F. placidus provides a much-needed pure culture model for further studies on the anaerobic activation of benzene in microorganisms. PMID:21742914

  9. Experimental investigation of electron and positron interactions with monosubstituted and disubstituted benzene derivatives: fluorobenzene, 1, 3-difluorobenzene and 1, 4-difluorobenzene molecules

    International Nuclear Information System (INIS)

    Makochekanwa, C; Sueoka, O; Kimura, M

    2004-01-01

    Electron and positron scattering from fluorobenzene (C 6 H 5 F), 1, 3-difluorobenzene (1, 3-C 6 H 4 F 2 ) and 1, 4-difluorobenzene (1, 4-C 6 H 4 F 2 ) molecules have been investigated experimentally using the linear transmission time-of-flight method. Total cross sections (TCSs) were measured and determined for 0.8-600 eV and 0.7-600 eV, respectively, for electron and positron scattering from 1, 3-C 6 H 4 F 2 and 1, 4-C 6 H 4 F 2 molecules, and 0.4-1000 eV and 0.2-1000 eV, respectively, for electron and positron scattering from C 6 H 5 F molecules. A broad resonance structure has been observed in the C 6 H 5 F electron TCSs at 0.8-1.6 eV, corresponding to the 1.6 eV 2 E 2u C 6 H 6 resonance structure. This broad structure seems to be made of two structures at 0.8 eV and 1.4 eV, which should mean that the original single 1.6 eV resonance peak in the C 6 H 6 parent molecule has split into two upon the monosubstitution of its H atom by the F atom. 1, 3-C 6 H 4 F 2 electron TCSs show a rising trend below 2 eV, a feature attributed to the polar nature of these molecules. Above 4 eV for all these three molecules, electron TCSs are greater than positron TCSs by a factor of ∼2 at energies up to 40 eV

  10. Alkyl-benzene-sulfonates; Alkylbenzenesulfonates

    Energy Technology Data Exchange (ETDEWEB)

    Marcou, L. [Ecole Superieure de Physique et Chimie Industrielles, 75 - Paris (France)]|[CEN, Comite europeen de normalisation (France)]|[Syndicat francais des producteurs d`agents de surface et produits auxiliaires industriels (ASPA) (France)

    1998-03-01

    The alkyl-benzene-sulfonates, or sulfophenyl-4-alkanes salts, (ABS) are anionic surface agents whose chemical formula is R-C{sub 6} H{sub 4}-SO{sub 3} M (where R is an aliphatic hydro-carbonated radical and M a metal). Like most of the surface agents, the ABS are complicated mixtures of isomers and homologues, the most usual products having 10 or 13 atoms of carbons. Their chemical preparation is carried out in two steps: 1)the alkyl-benzenes production by the alkanes or alkenes condensation on benzene 2)the alkyl-benzenes sulfonation and the neutralization of the sulfonic acids. The environmental impacts of these compounds are also given. (O.M.) 11 refs.

  11. Experimental studies of morphology development

    International Nuclear Information System (INIS)

    Whitton, J.L.

    1986-01-01

    This contribution is a resume of the approximately eight years of experimental investigation of ion beam-induced modification of metal surfaces. The aim, from the beginning, was to make a detailed series of experiments with well defined controllable parameters in an attempt to establish the mechanism responsible for the production of the topographical features observed so frequently on ion-bombarded surfaces of metals. Typically, for the initial system, 40 keV argon ions directed on to copper, the sputtering yield is fairly constant from normal angle of incidence to about 30 0 , rising fairly smoothly to a maximum at 80 0 , then dropping rapidly to zero at around 82 0 . A very strong grain orientation effect was observed in the early experiments. (Auth.)

  12. Experimental studies on cancer chemotherapy

    International Nuclear Information System (INIS)

    1976-08-01

    The further development of the chemotherapy of cancer in the experimental and clinical fields necessitates a profound knowledge of its chemical, biochemical and pharmacological fundamentals and the mechanism of physiological and pathological growth processes. The 'Arbeitsgemeinschaft Zytostatika' includes chemists, biochemists, pharmacologists, molecular biologists, physicians and immunologists of various scientific institutes and clinics in the Federal Republic of Germany and in West Berlin. It is their aim to carry out basic research as well as clinical-orientated research in the field of the chemotherapy of cancer. In the 15 years of cooperation, fundamental knowledge was gained, especially in the field of the cytotoxic specificity and cancerotoxic selectivity of alkylating cytostatics. New cytostatics with a greater oncostatic selectivity and an altered spectrum of activity were tested and greater knowledge was won on the molecular-biological prerequisites of a rational drug design. (orig.) [de

  13. Benzene exposure is associated with cardiovascular disease risk.

    Directory of Open Access Journals (Sweden)

    Wesley Abplanalp

    Full Text Available Benzene is a ubiquitous, volatile pollutant present at high concentrations in toxins (e.g. tobacco smoke known to increase cardiovascular disease (CVD risk. Despite its prevalence, the cardiovascular effects of benzene have rarely been studied. Hence, we examined whether exposure to benzene is associated with increased CVD risk. The effects of benzene exposure in mice were assessed by direct inhalation, while the effects of benzene exposure in humans was assessed in 210 individuals with mild to high CVD risk by measuring urinary levels of the benzene metabolite trans,trans-muconic acid (t,t-MA. Generalized linear models were used to assess the association between benzene exposure and CVD risk. Mice inhaling volatile benzene had significantly reduced levels of circulating angiogenic cells (Flk-1+/Sca-1+ as well as an increased levels of plasma low-density lipoprotein (LDL compared with control mice breathing filtered air. In the human cohort, urinary levels of t,t-MA were inversely associated several populations of circulating angiogenic cells (CD31+/34+/45+, CD31+/34+/45+/AC133-, CD34+/45+/AC133+. Although t,t-MA was not associated with plasma markers of inflammation or thrombosis, t,t-MA levels were higher in smokers and in individuals with dyslipidemia. In smokers, t,t-MA levels were positively associated with urinary metabolites of nicotine (cotinine and acrolein (3-hydroxymercapturic acid. Levels of t,t-MA were also associated with CVD risk as assessed using the Framingham Risk Score and this association was independent of smoking. Thus, benzene exposure is associated with increased CVD risk and deficits in circulating angiogenic cells in both smokers and non-smokers.

  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. Reactions of benzene oxide with thiols including glutathione.

    Science.gov (United States)

    Henderson, Alistair P; Barnes, Martine L; Bleasdale, Christine; Cameron, Richard; Clegg, William; Heath, Sarah L; Lindstrom, Andrew B; Rappaport, Stephen M; Waidyanatha, Suramya; Watson, William P; Golding, Bernard T

    2005-02-01

    S-Phenylmercapturic acid is a minor metabolite of benzene used as a biomarker for human benzene exposures. The reaction of intracellular glutathione with benzene oxide-oxepin, the initial metabolite of benzene, is presumed to give 1-(S-glutathionyl)-cyclohexa-3,5-dien-2-ol, which undergoes dehydration to S-phenylglutathione, the precursor of S-phenylmercapturic acid. To validate the proposed route to S-phenylglutathione, reactions of benzene oxide-oxepin with glutathione and other sulfur nucleophiles have been studied. The reaction of benzene oxide with an excess of aqueous sodium sulfide, followed by acetylation, gave bis-(6-trans-5-acetoxycyclohexa-1,3-dienyl)sulfide, the structure of which was proved by X-ray crystallography. Reactions of benzene oxide-oxepin in a 95:5 (v/v) mixture of phosphate buffer in D2O with (CD3)2SO were monitored by 1H NMR spectroscopy. In the absence of glutathione, the half-life of benzene oxide-oxepin was ca. 34 min at 25 degrees C and pD 7.0. The half-life was not affected in the range of 2-15 mM glutathione in the presence and absence of a commercial sample of human glutathione S-transferase (at pH 7.0, 8.0, 8.5, or 10.0). The adduct 1-(S-glutathionyl)-cyclohexa-3,5-diene-2-ol was identified in these reaction mixtures, especially at higher pH, by mass spectrometry and by its acid-catalyzed decomposition to S-phenylglutathione. Incubation of benzene oxide with N-acetyl-L-cysteine at 37 degrees C and pH 10.0 and subsequent mass spectrometric analysis of the mixture showed formation of pre-S-phenylmercapturic acid and the dehydration product, S-phenylmercapturic acid. The data validate the premise that benzene oxide-oxepin can be captured by glutathione to give (1R,2R)- and/or (1S,2S)-1-(S-glutathionyl)-cyclohexa-3,5-dien-2-ol, which dehydrate to S-phenylglutathione. The capture is a relatively inefficient process at pH 7 that is accelerated at higher pH. These studies account for the observation that the metabolism of benzene is

  16. 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...

  17. Benzene degradation in a denitrifying biofilm reactor: activity and microbial community composition.

    Science.gov (United States)

    van der Waals, Marcelle J; Atashgahi, Siavash; da Rocha, Ulisses Nunes; van der Zaan, Bas M; Smidt, Hauke; Gerritse, Jan

    2017-06-01

    Benzene is an aromatic compound and harmful for the environment. Biodegradation of benzene can reduce the toxicological risk after accidental or controlled release of this chemical in the environment. In this study, we further characterized an anaerobic continuous biofilm culture grown for more than 14 years on benzene with nitrate as electron acceptor. We determined steady state degradation rates, microbial community composition dynamics in the biofilm, and the initial anaerobic benzene degradation reactions. Benzene was degraded at a rate of 0.15 μmol/mg protein/day and a first-order rate constant of 3.04/day which was fourfold higher than rates reported previously. Bacteria belonging to the Peptococcaceae were found to play an important role in this anaerobic benzene-degrading biofilm culture, but also members of the Anaerolineaceae were predicted to be involved in benzene degradation or benzene metabolite degradation based on Illumina MiSeq analysis of 16S ribosomal RNA genes. Biomass retention in the reactor using a filtration finger resulted in reduction of benzene degradation capacity. Detection of the benzene carboxylase encoding gene, abcA, and benzoic acid in the culture vessel indicated that benzene degradation proceeds through an initial carboxylation step.

  18. 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.

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

    International Nuclear Information System (INIS)

    Vonk, W.F.M.

    1980-01-01

    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 NO 2 is determined. (C.F.)

  20. EXPERIMENTAL STUDY IN NATURAL CONVECTION

    African Journals Online (AJOL)

    PROF. BARTH EKWEME

    (collector) is made of a transparent cover (made of glass or plastic or a .... Glass. 1.3. 11.05. 2013. Amir and Hadi, (2015) brought an innovation to the design of a solar tower of 2.6m in height, with a cylindrical collector of 0.92m in height and 0.9m in diameter. ... mass flow to study the friction phenomena inside the chimney ...

  1. Vacuum ultraviolet photoabsorption spectroscopy of crystalline and amorphous benzene

    DEFF Research Database (Denmark)

    Dawes, Anita; Pascual, Natalia; Hoffmann, Soren V.

    2017-01-01

    We present the first high resolution vacuum ultraviolet photoabsorption study of amorphous benzene with com parisons to annealed crystalline benzene and the gas phase. Vapour deposited benzene layers w ere grow n at 25 K and annealed to 90 K under conditions pertinent to interstellaricy dust grains...... and icy planetary bodies in our solar system. Three single t-single t electronic transitions in solid benzene correspond to the B-1(2u), B-1(1u) and E-1(1u) states, redshifted by 0.05, 0.25 and 0.51 eV respectively with respect to the gas phase. The symmetry forbidden B-1(2u)...

  2. Formation of reactive metabolites from benzene

    International Nuclear Information System (INIS)

    Snyder, R.; Jowa, L.; Witz, G.; Kalf, G.; Rushmore, T.

    1986-01-01

    Rat liver mitoplasts were incubated first with [ 3 H]dGTP, to form DNA labeled in G, and then with [ 14 C]benzene. The DNA was isolated and upon isopycnic density gradient centrifugation in CsCl yielded a single fraction of DNA labeled with both [ 3 H] and [ 14 C]. 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. [ 3 H]Deoxyguanosine was reacted with [ 14 C]hydroquinone or benzoquinone. The product was characterized using uv, fluorescence, mass and NMR spectroscopy. A proposed structure is described. (orig.)

  3. Experimental study of urea granulation

    International Nuclear Information System (INIS)

    Irshad, U.; Sharif, M.N.; Rabbani, F.; Rauf, A.; Saleem, M.

    2009-01-01

    Urea is a nitrogenous fertilizer available in two commercial forms, prills and granules, in Pakistan. Prills are more common in Pakistan, however, it has some problems associated with it. Those are moisture, biuret contents of urea prills, prill size, hardness of prills, caking of prills and urea dust emission. Due to these problems urea granulation is favoured over prilling. Urea granulation is studied on laboratory scale using pan granulator and effect of different parameters like binders (water and urea solution), quantity of binders, rpm of pan granulator, time of granulation and angle of inclination on granulation yield is studied. Water and urea solutions of different concentrations are used and results reveal that concentration of urea solution is proportional to rate of granulation. A threshold quantity of binder is required for optimum granulation yield. RPM of pan is inversely proportional to rate of granulation. Granulation yield is also proportional to time of granulation however it becomes critical at a certain point. Angle of inclination of pan has no significant effects on granulation yield. (author)

  4. Benzene formation in electronic cigarettes.

    Directory of Open Access Journals (Sweden)

    James F Pankow

    Full Text Available The heating of the fluids used in electronic cigarettes ("e-cigarettes" used to create "vaping" aerosols is capable of causing a wide range of degradation reaction products. We investigated formation of benzene (an important human carcinogen from e-cigarette fluids containing propylene glycol (PG, glycerol (GL, benzoic acid, the flavor chemical benzaldehyde, and nicotine.Three e-cigarette devices were used: the JUULTM "pod" system (provides no user accessible settings other than flavor cartridge choice, and two refill tank systems that allowed a range of user accessible power settings. Benzene in the e-cigarette aerosols was determined by gas chromatography/mass spectrometry. Benzene formation was ND (not detected in the JUUL system. In the two tank systems benzene was found to form from propylene glycol (PG and glycerol (GL, and from the additives benzoic acid and benzaldehyde, especially at high power settings. With 50:50 PG+GL, for tank device 1 at 6W and 13W, the formed benzene concentrations were 1.9 and 750 μg/m3. For tank device 2, at 6W and 25W, the formed concentrations were ND and 1.8 μg/m3. With benzoic acid and benzaldehyde at ~10 mg/mL, for tank device 1, values at 13W were as high as 5000 μg/m3. For tank device 2 at 25W, all values were ≤~100 μg/m3. These values may be compared with what can be expected in a conventional (tobacco cigarette, namely 200,000 μg/m3. Thus, the risks from benzene will be lower from e-cigarettes than from conventional cigarettes. However, ambient benzene air concentrations in the U.S. have typically been 1 μg/m3, so that benzene has been named the largest single known cancer-risk air toxic in the U.S. For non-smokers, chronically repeated exposure to benzene from e-cigarettes at levels such as 100 or higher μg/m3 will not be of negligible risk.

  5. Benzene formation in electronic cigarettes.

    Science.gov (United States)

    Pankow, James F; Kim, Kilsun; McWhirter, Kevin J; Luo, Wentai; Escobedo, Jorge O; Strongin, Robert M; Duell, Anna K; Peyton, David H

    2017-01-01

    The heating of the fluids used in electronic cigarettes ("e-cigarettes") used to create "vaping" aerosols is capable of causing a wide range of degradation reaction products. We investigated formation of benzene (an important human carcinogen) from e-cigarette fluids containing propylene glycol (PG), glycerol (GL), benzoic acid, the flavor chemical benzaldehyde, and nicotine. Three e-cigarette devices were used: the JUULTM "pod" system (provides no user accessible settings other than flavor cartridge choice), and two refill tank systems that allowed a range of user accessible power settings. Benzene in the e-cigarette aerosols was determined by gas chromatography/mass spectrometry. Benzene formation was ND (not detected) in the JUUL system. In the two tank systems benzene was found to form from propylene glycol (PG) and glycerol (GL), and from the additives benzoic acid and benzaldehyde, especially at high power settings. With 50:50 PG+GL, for tank device 1 at 6W and 13W, the formed benzene concentrations were 1.9 and 750 μg/m3. For tank device 2, at 6W and 25W, the formed concentrations were ND and 1.8 μg/m3. With benzoic acid and benzaldehyde at ~10 mg/mL, for tank device 1, values at 13W were as high as 5000 μg/m3. For tank device 2 at 25W, all values were ≤~100 μg/m3. These values may be compared with what can be expected in a conventional (tobacco) cigarette, namely 200,000 μg/m3. Thus, the risks from benzene will be lower from e-cigarettes than from conventional cigarettes. However, ambient benzene air concentrations in the U.S. have typically been 1 μg/m3, so that benzene has been named the largest single known cancer-risk air toxic in the U.S. For non-smokers, chronically repeated exposure to benzene from e-cigarettes at levels such as 100 or higher μg/m3 will not be of negligible risk.

  6. 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.

  7. Synthesis, characterization and computational studies of 3-{(E)-[(2-hydroxyphenyl)imino]methyl}benzene-1,2-diol and molecular structure of its zwitterionic form

    Science.gov (United States)

    Ezeorah, Julius Chigozie; Ossai, Valentine; Obasi, Lawrence Nnamdi; Elzagheid, Mohamed I.; Rhyman, Lydia; Lutter, Michael; Jurkschat, Klaus; Dege, Necmi; Ramasami, Ponnadurai

    2018-01-01

    The Schiff base 3-{(E)-[(2-hydroxyphenyl)imino]methyl}benzene-1,2-diol was synthesized by the condensation of 2,3-dihydroxybenzaldehyde and 2-aminophenol in water at room temperature. The crystal was grown using two solvents (dry methanol and 60% methanol). The compound was characterized using elemental microanalysis, IR, NMR, UV spectroscopies and single-crystal X-ray diffraction crystallography. The X-ray structure reveals that the Schiff base crystallizes as a methanol solvate in dry methanol with triclinic crystal system, space group P-1 and Z = 2 in the unit cell and as a non-methanol solvate in 60% methanol with triclinic crystal system, space group P-1 and Z = 4 in the unit cell. The compound showed absorption bands at 272, 389, 473 and 602 nm in DMSO. These bands were assigned as π → π ∗, n → π∗ and n-σ∗ transitions. The 473 and 602 nm bands in DMSO reveal that the compound exists in tautomeric forms. The presence of N-H, C-O and Cdbnd N stretching vibrations in the IR spectrum indicates that the compound is zwitterionic in the solid state. This study was supplemented using density functional theory method.

  8. Normal and Inverse Diffusive Isotope Fractionation of Deuterated Toluene and Benzene in Aqueous Systems

    DEFF Research Database (Denmark)

    Rolle, Massimo; Jin, Biao

    2017-01-01

    Diffusive isotope fractionation of organic contaminants in aqueous solution is difficult to quantify, and only a few experimental data sets are available for compounds of environmental interest. In this study, we investigate diffusive fractionation of perdeuterated and nondeuterated benzene...... of the two monoaromatic hydrocarbons. Toluene showed a normal diffusive isotope effect (DC7D8/DC7H8 = 0.96) with enrichment of the nondeuterated isotopologue in the direction of the diffusive and transverse dispersive fluxes. Conversely, the measured trends for benzene indicate inverse diffusive...... fractionation (DC6D6/DC6H6 = 1.02), with a remarkably faster diffusion rate of the perdeuterated isotopologue that was enriched in the downgradient portion of the diffusion tubes and at the fringes of the contaminant plumes in the flow-through setup. These outcomes can neither be interpreted as mass...

  9. Problem Definition Studies on Potential Environmental Pollutants. 4. Physical, Chemical, Toxicological, and Biological Properties of Benzene; Toluene; Xylenes; and para-Chlorophenyl Methyl Sulfide, Sulfoxide, and Sulfone

    Science.gov (United States)

    1976-06-01

    Amounts of Benzene in the Air of Industrial Facilities," r ’Koks I Khimiya, 5:36-67 (1973); C.A., 79, 34722h (1973). 48. Balint , T., S. Igelewski, E...5:36-37 (1973); C.A., 79:34722H (1973). 26. Balint , T., S. Igelewski, E. Kerenyi, J. Stumpfhauser, G. Kerenyi and T. Molnar, "Apparatus for Measuring...34Detennina- tion of Small Amounts of Benzene in the Air of Industrial Facil-ities," Koks I Khlrn, 5:36-37 (1973); C.A.. 79:34722H1 (1973). 77 23. Balint

  10. On the structure and reactivity of small iron clusters with benzene, [Fen-C6H6]0,+,-, n ⩽ 7: A theoretical study

    Science.gov (United States)

    Valencia, Israel

    2016-09-01

    The structural, energetic, electronic, vibrational, and magnetic properties of iron-benzene clusters, Fen-C6H6, n ⩽ 7, were calculated using an all-electron density functional theory, DFT, with the generalized gradient approximation and the 6-311++G(2d,2p) basis set. A proposal regarding the mechanism of the adsorption of benzene on iron clusters related to the charge transfer model is described. A direct relation between the calculated electron affinity, EA, of the Fen-C6H6 clusters and their reactivity were also determined.

  11. Combined Teaching Method: An Experimental Study

    Science.gov (United States)

    Kolesnikova, Iryna V.

    2016-01-01

    The search for the best approach to business education has led educators and researchers to seek many different teaching strategies, ranging from the traditional teaching methods to various experimental approaches such as active learning techniques. The aim of this experimental study was to compare the effects of the traditional and combined…

  12. 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.

  13. Adverse Health Effects of Benzene Exposure Among Children Following a Flaring Incident at the British Petroleum Refinery in Texas City.

    Science.gov (United States)

    D'Andrea, Mark A; Reddy, G Kesava

    2016-03-01

    This study examined the health effects of benzene exposure among children from a flaring incident at the British Petroleum (BP) refinery in Texas City, Texas. A total of 899 children (benzene exposed, n = 641 and unexposed, n = 258), aged benzene are at a higher risk of developing both hepatic and bone marrow-related disorders. © The Author(s) 2015.

  14. 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...

  15. Bioremediation of Benzene-contaminated Underground Aquifers

    Science.gov (United States)

    Watanabe, Kazuya; Takahata, Yoh

    Contamination of underground aquifers with gasoline occurs frequently. Among the gasoline constituents, benzene is of great environmental concern, since it is carcinogenic, water-soluble and persistent under anaerobic conditions. We have analyzed a gasoline-contaminated underground aquifer undergoing natural attenuation, where benzene was degraded, albeit slowly, under anaerobic conditions. RNA-based stable-isotope probing identified that bacteria affiliated with the genus AZOARCUS was responsible for benzene degradation under nitrate-reducing conditions. This result was confirmed by isolating an anaerobic benzene-degrading bacterium AZOARCUS sp. strain DN11. This strain degraded benzene at relatively low concentrations (as low as 10 ppb). It could also degrade toluene and xylenes. In laboratory bioaugmentation experiments using benzene-contaminated groundwater, it was demonstrated that supplementation with DN11 significantly accelerated benzene degradation under a nitrate-reducing condition. These results indicate that DN11 is potentially useful for degrading benzene that contaminates underground aquifers at relatively low concentrations.

  16. A complete computational and spectroscopic study of 2-bromo-1, 4-dichlorobenzene - A frequently used benzene derivative

    Science.gov (United States)

    Vennila, P.; Govindaraju, M.; Venkatesh, G.; Kamal, C.; Mary, Y. Sheena; Panicker, C. Yohannan; Kaya, S.; Armaković, Stevan; Armaković, Sanja J.

    2018-01-01

    The coupled experimental and theoretical vibrational investigation of 2-bromo-1, 4-dichlorobenzene (BDB) molecule has been carried out and they have been duly compared with standard values in order to produce the reliability of the results. Results of DFT analysis carried out using B3LYP functional with 6-31 + G/6-311++G (d,p) basis set revealed that BDB has higher electronic density. The molecular geometry, 13C &1H Nuclear Magnetic Resonance (NMR), Natural Bond Orbital (NBO) and Natural Atomic Charge analyses have been obtained by DFT calculations. Nonlinear optical (NLO) properties, quantum chemical descriptors and first order hyperpolarizability have been calculated. In addition, Local reactivity properties reflected through average local ionization energies (ALIE), Fukui functions and bond dissociation energies have also been investigated. Besides investigation of docking properties, molecular dynamics simulations were also taken in account with a view to identify atoms that have relatively important interactions with water molecules. The title compound forms a stable complex with isopentenylpyrophosphate transferase with a binding affinity value as -4.6 kCal./Mol. and shows inhibitory activity against isopentenylpyrophosphate transferase.

  17. The resonance energy of benzene: a revisit.

    Science.gov (United States)

    Mo, Yirong

    2009-04-30

    Zielinski and van Lenthe recently extended the block-localized wave function (BLW) method by introducing the resonating BLW (RBLW) method and performed test calculations on hexagonal H(6) and benzene [J. Phys. Chem. A 2008, 112, 13197]. However, the Pauling's resonance energies from their RBLW and ab initio valence bond (VB) calculations were greatly underestimated largely due to the imperfect use of either one-electron orbitals (method = delocal) or resonance structures (method = local). Whereas it has been well recognized that electronic resonance within a molecular system plays a stabilizing role, there are many indirect experimental evidences available to evaluate the resonance energy and, thus, to justify computational results. Here we used the BLW method, which can be regarded as the simplest variant of modern ab initio VB theory, to re-evaluate the resonance energy of benzene at the B3LYP level, following the original definition by Pauling and Wheland, who obtained the resonance energy "by subtracting the actual energy of the molecule in question from that of the most stable contributing structure". The computed vertical resonance energy (or quantum mechanical resonance energy) in benzene is 88.8, 92.2, or 87.9 kcal/mol with the basis sets of 6-31G(d), 6-311+G(d,p), or cc-pVTZ, respectively, while the adiabatic resonance energy (or theoretical resonance energy) is 61.4, 63.2, or 62.4 kcal/mol, exhibiting insignificant basis set dependency for moderate basis sets. In line with predictions, the geometry optimization of the elusive cyclohexatriene (i.e., the Kekule structure) with the BLW method also resulted in carbon-carbon bond lengths (e.g., 1.322 and 1.523 A with the cc-pVTZ basis set) comparable to those in ethylene or ethane.

  18. 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 benzene...

  19. 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 distilled...

  20. CCDC 877428: Experimental Crystal Structure Determination : Deca-nickel oxonium octakis(benzene-1,3,5-tricarboxylate) (5,10,15,20-tetrakis(N-methyl-4-pyridinio)porphyrin)-nickel tetracosahydrate

    KAUST Repository

    Zhang, Zhenjie

    2012-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  1. CCDC 1010338: Experimental Crystal Structure Determination : catena-[hexakis(mu-isonicotinato)-(mu-oxo)-tris(mu-benzene-1,4-dicarboxylato)-hydroxo-diaqua-tri-chromium-tri-zinc unknown solvate

    KAUST Repository

    Schoedel, Alexander

    2014-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  2. CCDC 1408400: Experimental Crystal Structure Determination : catena-(tris(mu-5,5'-(diazene-1,2-diyl)bis(benzene-1,3-dicarboxylato))-bis(mu-oxo)-hexa-aqua-hexa-iron dichloride unknown solvate)

    KAUST Repository

    Cairns, Amy J.

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  3. CCDC 1408399: Experimental Crystal Structure Determination : catena-(tris(mu-5,5'-(diazene-1,2-diyl)bis(benzene-1,3-dicarboxylato))-bis(mu-oxo)-hexa-aqua-hexa-iron dinitrate unknown solvate hydrate)

    KAUST Repository

    Cairns, Amy J.

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  4. CCDC 877430: Experimental Crystal Structure Determination : catena-(octakis(mu~6~-Benzene-1,3,5-tricarboxylato)-dodeca-aqua-dodeca-iron hemikis((5,10,15,20-tetrakis(N-methylpyridinium-4-yl)porphyrinato)-iron) chloride)

    KAUST Repository

    Zhang, Zhenjie

    2012-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  5. CCDC 857933: Experimental Crystal Structure Determination : (eta^3^-1-Phenylallyl)-chloro-(1,3-bis(2,6-bis(diphenylmethyl)-4-methylphenyl)-1,3-dihydro-2H-imidazol-2-ylidene)-palladium benzene solvate

    KAUST Repository

    Chartoire, A.

    2012-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  6. CCDC 953496: Experimental Crystal Structure Determination : catena-[bis(Dimethylammonium) hexakis(mu~6~-1,3,5-tris(4-carboxylatophenyl)benzene)-octakis(mu~3~-hydroxo)-tris(mu~2~-hydroxo)-nona-yttrium(iii) unknown solvate

    KAUST Repository

    Guillerm, Vincent

    2014-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  7. CCDC 939822: Experimental Crystal Structure Determination : catena-[hexakis(mu3-Isonicotinamide)-bis(mu3-benzene-1,3,5-tricarboxylato)-(mu3-oxo)-diaqua-hydroxy-tri-chromium-tri-zinc dimethylformamide solvate

    KAUST Repository

    Schoedel, Alexander

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  8. CCDC 939824: Experimental Crystal Structure Determination : catena-[hexakis(mu3-Isonicotinamido)-bis(mu3-1,3,5-tris(4-carboxylatophenyl)benzene)-(mu3-oxo)-diaqua-hydroxy-tri-chromium-tri-zinc dimethylformamide solvate

    KAUST Repository

    Schoedel, Alexander

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  9. CCDC 939823: Experimental Crystal Structure Determination : catena-[hexakis(mu3-Isonicotinamide)-bis(mu3-benzene-1,3,5-tricarboxylato)-(mu3-oxo)-tripyridyl-tri-chromium-tri-zinc pyridine solvate

    KAUST Repository

    Schoedel, Alexander

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  10. CCDC 1436350: Experimental Crystal Structure Determination : 3,6-difluoro-N,N,N',N',N'',N'',N''',N'''-octakis(4-methoxyphenyl)benzene-1,2,4,5-tetramine dichloromethane solvate

    KAUST Repository

    Chen, Hu

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  11. CCDC 877431: Experimental Crystal Structure Determination : catena-(octakis(mu~6~-Benzene-1,3,5-tricarboxylato)-dodeca-aqua-dodeca-cobalt (5,10,15,20-tetrakis(N-methylpyridinium-4-yl)porphyrinato)-cobalt chloride hydrate)

    KAUST Repository

    Zhang, Zhenjie

    2012-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  12. CCDC 877429: Experimental Crystal Structure Determination : Octadeca-zinc oxonium dodecakis(benzene-1,3,5-tricarboxylate) (5,10,15,20-tetrakis(N-methyl-4-pyridinio)porphyrin)-zinc tetrahydroxide pentadecahydrate

    KAUST Repository

    Zhang, Zhenjie

    2012-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  13. CCDC 877427: Experimental Crystal Structure Determination : catena-(octakis(mu~6~-Benzene-1,3,5-tricarboxylato)-dodeca-aqua-dodeca-manganese (5,10,15,20-tetrakis(N-methylpyridinium-4-yl)porphyrinato)-manganese chloride)

    KAUST Repository

    Zhang, Zhenjie

    2012-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  14. CCDC 1050062: Experimental Crystal Structure Determination : catena-[bis(dimethylammonium) octakis(mu-hydroxo)-tris(mu-1,2,4,5-tetrakis[(4-carboxylato)phenoxymethyl]benzene)-hexaaqua-hexa-yttrium unknown solvate monohydrate

    KAUST Repository

    Luebke, Ryan

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  15. CCDC 1432978: Experimental Crystal Structure Determination : catena-[tris(mu-1,4-bis(4,4''-dicarboxylato-1,1':3',1''-terphenyl-5'-yl)benzene)-bis(mu-oxo)-hexaaqua-hexa-aluminium dichloride

    KAUST Repository

    Alezi, Dalal

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  16. CCDC 866714: Experimental Crystal Structure Determination : catena-(bis(mu~12~-5,5',5''-(Benzene-1,3,5-triyltris(methyleneoxy-4,1-phenylenediazene-2,1-diyl))triisophthalato)-hexa-aqua-hexa-zinc)

    KAUST Repository

    Eubank, J.F.

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  17. CCDC 884451: Experimental Crystal Structure Determination : catena-(hexakis(mu~6~-5'-(4-(1H-tetrazol-5-yl)benzamido)benzene-1,3-dioato)-bis(mu~3~-oxo)-tetracosa-aqua-dodeca-copper)

    KAUST Repository

    Eubank, J.F.

    2013-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  18. On Benzene and Aromaticity

    Indian Academy of Sciences (India)

    intuition, deduction and simple experimentation also need to be retold. The creativity of scientists has an appeal that transcends the subject. Chemistry of aromatic compounds provides ample opportunities for the teacher to cover many of the above aspects. One can move from almost trivial questions to those that require ...

  19. Establishment of a Methanogenic Benzene-Degrading Culture and its Implication in Bioremediation

    Science.gov (United States)

    Qiao, W.; Luo, F.; Bawa, N.; Guo, S.; Ye, S.; Edwards, E.

    2017-12-01

    Benzene is a known human carcinogen and it is a common pollutant in groundwater, mainly resulting from petrochemical industry. Anaerobic degradation of benzene has significant advantages over aerobic processes for in situ bioremediation. In this study, new methanogenic and sulfate-reducing benzene degrading cultures have been enriched. Microbial community composition was characterized with two other previously established benzene-degrading cultures, and their potential use in bioaugmentation is investigated. In this study, a lab microcosm study was conducted anaerobically with contaminated soil and groundwater from a former chemical plant. Benzene degradation was observed in the presence of co-contaminants and electron donor. Through repetitive amendment of benzene, two enrichment cultures have been developed under sulfate and methanogenic conditions. Results from DNA amplicon sequencing and qPCR analysis revealed that an organism similar to previously described benzene-degrading Deltaproteobacterium has been enriched. The microbial community of this culture was compared with other two methanogenic benzene-degrading enrichment cultures that were derived from an oil refinery and a decommissioned gasoline station, and have been maintained for decades. Deltaproteobacterium ORM2-like microbes were dominate in all enrichment cultures, which brought to light benzene-degrading microbes, ORM2 were enriched under different geological conditions distributed around the world. The relative abundance of methanogens was much lower compared to previously established cultures, although substantial amount of methane was produced. The peripheral organisms also vary. To investigate effectiveness of using ORM2-dominant enrichment cultures in bioremediation, microcosm studies were set up using contaminated materials, and a ORM2-dominating methanogenic benzene-degrading culture was used for bioaugmentation. Results revealed that benzene degradation was speeded up under methanogenic or

  20. Stability, structural and electronic properties of benzene molecule adsorbed on free standing Au layer

    Energy Technology Data Exchange (ETDEWEB)

    Katoch, Neha, E-mail: nehakatoch2@gmail.com; Kapoor, Pooja; Sharma, Munish; Ahluwalia, P. K. [Physics Department, Himachal Pradesh University, Shimla, Himachal Pradesh, India 171005 (India); Kumar, Ashok [Center for Physical Sciences, School of Basic and Applied Sciences, Central University of Punjab, Bathinda, India, 151001 (India)

    2016-05-23

    We report stability and electronic properties of benzene molecule adsorbed on the Au atomic layer within the framework of density function theory (DFT). Horizontal configuration of benzene on the top site of Au monolayer prefers energetically over other studied configurations. On the adsorption of benzene, the ballistic conductance of Au monolayer is found to decrease from 4G{sub 0} to 2G{sub 0} suggesting its applications for the fabrications of organic sensor devices based on the Au atomic layers.

  1. Hepatic encephalopathy: experimental studies on the pathogenesis

    NARCIS (Netherlands)

    R.J. de Knegt (Robert)

    1993-01-01

    textabstractAims of this thesis: 1. To study, in rabbits, the suitability of experimental acute liver failure and acute hyperammonemia simulating acute liver failure for the study of hepatic encephalopathy and ammonia toxicity. 2. To study glutamate neurotransmission in rabbits with acute liver

  2. Benzene-contaminated groundwater remediation using calcium peroxide nanoparticles: synthesis and process optimization.

    Science.gov (United States)

    Mosmeri, Hamid; Alaie, Ebrahim; Shavandi, Mahmoud; Dastgheib, Seyed Mohammad Mehdi; Tasharrofi, Saeideh

    2017-08-14

    Nano-size calcium peroxide (nCaO 2 ) is an appropriate oxygen source which can meet the needs of in situ chemical oxidation (ISCO) for contaminant remediation from groundwater. In the present study, an easy to handle procedure for synthesis of CaO 2 nanoparticles has been investigated. Modeling and optimization of synthesis process was performed by application of response surface methodology (RSM) and central composite rotatable design (CCRD) method. Synthesized nanoparticles were characterized by XRD and FESEM techniques. The optimal synthesis conditions were found to be 5:1, 570 rpm and 10 °C for H 2 O 2 :CaSO 2 ratio, mixing rate and reaction temperature, respectively. Predicted values showed to be in good agreement with experimental results (R 2 values were 0.915 and 0.965 for CaO 2 weight and nanoparticle size, respectively). To study the efficiency of synthesized nanoparticles for benzene removal from groundwater, batch experiments were applied in biotic and abiotic (chemical removal) conditions by 100, 200, 400, and 800 mg/L of nanoparticles within 70 days. Results indicated that application of 400 mg/L of CaO 2 in biotic condition was able to remediate benzene completely from groundwater after 60 days. Furthermore, comparison of biotic and abiotic experiments showed a great potential of microbial stimulation using CaO 2 nanoparticles in benzene remediation from groundwater.

  3. 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 butyl...

  4. Experimental design of a waste glass study

    International Nuclear Information System (INIS)

    Piepel, G.F.; Redgate, P.E.; Hrma, P.

    1995-04-01

    A Composition Variation Study (CVS) is being performed to support a future high-level waste glass plant at Hanford. A total of 147 glasses, covering a broad region of compositions melting at approximately 1150 degrees C, were tested in five statistically designed experimental phases. This paper focuses on the goals, strategies, and techniques used in designing the five phases. The overall strategy was to investigate glass compositions on the boundary and interior of an experimental region defined by single- component, multiple-component, and property constraints. Statistical optimal experimental design techniques were used to cover various subregions of the experimental region in each phase. Empirical mixture models for glass properties (as functions of glass composition) from previous phases wee used in designing subsequent CVS phases

  5. Experimental radiation carcinogenesis is studies at NIRS

    International Nuclear Information System (INIS)

    Sado, Toshihiko

    1992-01-01

    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)

  6. Population exposure to benzene: One day cross-sections in six European cities

    Science.gov (United States)

    Ballesta, Pascual Pérez; Field, Robert A.; Connolly, Richard; Cao, Natale; Baeza Caracena, Antonia; De Saeger, Emile

    This paper describes the experimental methodology and basic results of the PEOPLE project (Population Exposure to Air Pollutants in Europe). Simultaneous diffusive measurements of outdoor, indoor and human exposure benzene concentrations were made during one day campaigns. Six cities were assessed, namely: Brussels and Lisbon (22 October 2002), Bucharest and Ljubljana (27 May 2003), Madrid (3 December 2003) and Dublin (28 April 2004). In general, human exposure to benzene was higher than concentrations reported at urban background monitoring sites. Traffic was the dominant source of benzene in all the six cities that were studied. The highest exposure levels from the commuting groups were car users. The control group, with no influence from commuting or smoking, reported concentrations closer to the background level of the city. The smoking group had the highest level of exposure. The level of exposure of school children was similar to that of the commuting groups. Indoor locations that were influenced by smoking sources, or with free access to busy streets, reported relatively high concentrations. The highest indoor concentrations were measured in bars and inside motor vehicles. When considering the six cities together, a linear relationship was evident between ambient levels and human exposure. Daily median values of human exposure for non-smoking commuters were 1.5 times the level of urban background and 0.6 times the maximum outdoor value (hotspot).

  7. 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.

  8. Assessing benzene-induced toxicity on wild type Euglena gracilis Z and its mutant strain SMZ.

    Science.gov (United States)

    Peng, Cheng; Arthur, Dionne M; Sichani, Homa Teimouri; Xia, Qing; Ng, Jack C

    2013-11-01

    Benzene is a representative member of volatile organic compounds and has been widely used as an industrial solvent. Groundwater contamination of benzene may pose risks to human health and ecosystems. Detection of benzene in the groundwater using chemical analysis is expensive and time consuming. In addition, biological responses to environmental exposures are uninformative using such analysis. Therefore, the aim of this study was to employ a microorganism, Euglena gracilis (E. gracilis) as a putative model to monitor the contamination of benzene in groundwater. To this end, we examined the wild type of E. gracilis Z and its mutant form, SMZ in their growth rate, morphology, chlorophyll content, formation of reactive oxygen species (ROS) and DNA damage in response to benzene exposure. The results showed that benzene inhibited cell growth in a dose response manner up to 48 h of exposure. SMZ showed a greater sensitivity compared to Z in response to benzene exposure. The difference was more evident at lower concentrations of benzene (0.005-5 μM) where growth inhibition occurred in SMZ but not in Z cells. We found that benzene induced morphological changes, formation of lipofuscin, and decreased chlorophyll content in Z strain in a dose response manner. No significant differences were found between the two strains in ROS formation and DNA damage by benzene at concentrations affecting cell growth. Based on these results, we conclude that E. gracilis cells were sensitive to benzene-induced toxicities for certain endpoints such as cell growth rate, morphological change, depletion of chlorophyll. Therefore, it is a potentially suitable model for monitoring the contamination of benzene and its effects in the groundwater. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

    Cervantes, Francisco J.; Mancilla, Ana Rosa; Toro, E. Emilia Rios-del; Alpuche-Solis, Angel G.; Montoya-Lorenzana, Lilia

    2011-01-01

    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.

  10. Experimental study on rapid embankment construction methods

    International Nuclear Information System (INIS)

    Hirano, Hideaki; Egawa, Kikuji; Hyodo, Kazuya; Kannoto, Yasuo; Sekimoto, Tsuyoshi; Kobayashi, Kokichi.

    1982-01-01

    In the construction of a thermal or nuclear power plant in a coastal area, shorter embankment construction period has come to be called for recently. This tendency is remarkable where construction period is limited due to meteorological or sea conditions. To meet this requirement, the authors have been conducting basic experimental studies on two methods for the rapid execution of embankment construction, that is, Steel Plate Cellular Bulkhead Embedding Method and Ship Hull Caisson Method. This paper presents an outline of the results of the experimental study on these two methods. (author)

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

    International Nuclear Information System (INIS)

    Medeiros Vinci, Raquel; Canfyn, Michael; De Meulenaer, Bruno; Schaetzen, Thibault de; Van Overmeire, Ilse; De Beer, Jacques; Van Loco, Joris

    2010-01-01

    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 ).

  12. Experimental study of the natural circulation phenomena

    International Nuclear Information System (INIS)

    Sabundjian, Gaiane; Andrade, Delvonei Alves de; Umbehaun, Pedro E.; Torres, Walmir M.; Castro, Alfredo Jose Alvim de; Belchior Junior, Antonio; Rocha, Ricardo Takeshi Vieira da; Damy, Osvaldo Luiz de Almeida; Torres, Eduardo

    2006-01-01

    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)

  13. Sulfur tolerance of Pt/mordenites for benzene hydrogenation. Do Bronsted acid sites participate in hydrogenation?

    NARCIS (Netherlands)

    Simon, L.; van Ommen, J.G.; Jentys, A.; Lercher, J.A.

    2002-01-01

    The comparison of Pt electronic properties studied by in situ XANES and the kinetic study of benzene hydrogenation strongly suggests that the hydrogenation of benzene on Pt/mordenites occurs along two parallel reaction pathways. The routes proposed include (i) the monofunctional hydrogenation of

  14. Benzene-free synthesis of adipic acid.

    Science.gov (United States)

    Niu, Wei; Draths, K M; Frost, J W

    2002-01-01

    Strains of Escherichia coli were constructed and evaluated that synthesized cis,cis-muconic acid from D-glucose under fed-batch fermentor conditions. Chemical hydrogenation of the cis,cis-muconic acid in the resulting fermentation broth has also been examined. Biocatalytic synthesis of adipic acid from glucose eliminates two environmental concerns characteristic of industrial adipic acid manufacture: use of carcinogenic benzene and benzene-derived chemicals as feedstocks and generation of nitrous oxide as a byproduct of a nitric acid catalyzed oxidation. While alternative catalytic syntheses that eliminate the use of nitric acid have been developed, most continue to rely on petroleum-derived benzene as the ultimate feedstock. In this study, E. coli WN1/pWN2.248 was developed that synthesized 36.8 g/L of cis,cis-muconic acid in 22% (mol/mol) yield from glucose after 48 h of culturing under fed-batch fermentor conditions. Optimization of microbial cis,cis-muconic acid synthesis required expression of three enzymes not typically found in E. coli. Two copies of the Klebsiella pneumoniae aroZ gene encoding DHS dehydratase were inserted into the E. coli chromosome, while the K. pneumoniae aroY gene encoding PCA decarboxylase and the Acinetobacter calcoaceticus catA gene encoding catechol 1,2-dioxygenase were expressed from an extrachromosomal plasmid. After fed-batch culturing of WN1/pWN2.248 was complete, the cells were removed from the broth, which was treated with activated charcoal and subsequently filtered to remove soluble protein. Hydrogenation of the resulting solution with 10% Pt on carbon (5% mol/mol) at 3400 kPa of H2 pressure for 2.5 h at ambient temperature afforded a 97% (mol/mol) conversion of cis,cis-muconic acid into adipic acid.

  15. Accumulation of chlorinated benzenes in earthworms

    Science.gov (United States)

    Beyer, W.N.

    1996-01-01

    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. This paper describes a long-term (26 week) experiment relating the concentrations of chlorinated benzenes in earthworms to 1) the length of exposure, and it describes three 8-week experiments relating concentrations of chlorinated benzenes in earthworms to 2) their concentration in soil 3) the soil organic matter content and, 4) the degree of chlorination. In the 26-week experiment, the concentration of 1,2,4 - trichlorobenzene in earthworms fluctuated only slightly about a mean of 0.63 ppm (Fig. 1). Although a statistically significant decrease can be demonstrated over the test (Pearson correlation coefficient, r = -0.62 p earthworms showed a cyclical trend that coincided with replacement of the media, and a slight but statistically significant tendency to increase from about 2 to 3 ppm over the 26 weeks (r = 0.55, p earthworms increased as the concentrations in the soil increased (Fig. 2), but leveled off at the highest soil concentrations. The most surprising result of this study was the relatively low concentrations in earthworms compared to those in soils. The average concentration of each of the six isomers of trichlorobenzene and tetrachlorobenzene in earthworms was only about 1 ppm (Table 2); the isomeric structure did not affect accumulation. The concentration of organic matter in soil had a prominent effect on hexachlorobenzene concentrations in earthworms (Fig. 3). Hexachlorobenzene concentrations decreased steadily from 9.3 ppm in earthworms kept in soil without any peat moss added to about 1 ppm in soil containing 16 or 32% organic matter.

  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. Experimental and computational study of thaumasite structure

    Energy Technology Data Exchange (ETDEWEB)

    Scholtzová, Eva, E-mail: Eva.Scholtzova@savba.sk [Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 36 Bratislava (Slovakia); Kucková, Lenka; Kožíšek, Jozef [Department of Physical Chemistry, Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, 812 37 Bratislava (Slovakia); Pálková, Helena [Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 36 Bratislava (Slovakia); Tunega, Daniel [Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 36 Bratislava (Slovakia); Institute for Soil Science, University of Natural Resources and Life Sciences, Peter-Jordanstrasse 82, A-1190 Wien (Austria)

    2014-05-01

    The structure of thaumasite has been studied experimentally by means of a single crystal X-ray diffraction and FTIR methods, and theoretically using density functional theory (DFT) method. Very good agreement was achieved between calculated and experimental structural parameters. In addition, calculations offered the refinement of the positions of the hydrogen atoms. The detailed analysis of the hydrogen bonds existing in the thaumasite structure has been performed. Several types of hydrogen bonds have been classified. The water molecules coordinating Ca{sup 2+} cation act as proton donors in moderate O-H···O hydrogen bonds formed with CO₃⁻²and SO₄⁻² anions. The multiple O-H···O hydrogen bonds exist among water molecules themselves. Finally, relatively weak hydrogen bonds form water molecules with the OH groups from the coordination sphere of the Si(OH)₆⁻² anion. Further, calculated vibrational spectrum allowed complete assignment of all vibrational modes which are not available from the experimental spectrum that has a complex structure with overlapped bands, especially below 1500 cm⁻¹. Highlights: • The thaumasite structure was studied experimentally and using DFT method. • We used DFT method for the refinement of the positions of hydrogen atoms. • A detailed analysis of the hydrogen bonds was done. • A complete assignment of all bands to particular types of vibrations was done.

  18. Experimental study of structural response to earthquakes

    International Nuclear Information System (INIS)

    Clough, R.W.; Bertero, V.V.; Bouwkamp, J.G.; Popov, E.P.

    1975-01-01

    The objectives, methods, and some of the principal results obtained from experimental studies of the behavior of structures subjected to earthquakes are described. Although such investigations are being conducted in many laboratories throughout the world, the information presented deals specifically with projects being carried out at the Earthquake Engineering Research Center (EERC) of the University of California, Berkeley. A primary purpose of these investigations is to obtain detailed information on the inelastic response mechanisms in typical structural systems so that the experimentally observed performance can be compared with computer generated analytical predictions. Only by such comparisons can the mathematical models used in dynamic nonlinear analyses be verified and improved. Two experimental procedures for investigating earthquake structural response are discussed: the earthquake simulator facility which subjects the base of the test structure to acceleration histories similar to those recorded in actual earthquakes, and systems of hydraulic rams which impose specified displacement histories on the test components, equivalent to motions developed in structures subjected to actual'quakes. The general concept and performance of the 20ft square EERC earthquake simulator is described, and the testing of a two story concrete frame building is outlined. Correlation of the experimental results with analytical predictions demonstrates that satisfactory agreement can be obtained only if the mathematical model incorporates a stiffness deterioration mechanism which simulates the cracking and other damage suffered by the structure

  19. [Benzene in food and human environment].

    Science.gov (United States)

    Jedra, Małgorzata; Starski, Andrzej

    2010-01-01

    Benzene is releasing to environment in cause of industry activities. This compound is known as carcinogenic. This article contains information about benzene occurrence in people environment and sources of people exposition on this compound. Toxicology and metabolism in human organism were discussed. Benzene contamination of various food was presented on the basis of our results and also other European and American investigations and Codex Alimentarius documents. Especially formation and occurrence of benzene in non-alcoholic beverages preserved by benzoates were considered. Article describes also action, which was taken up by non-alcoholic beverages industry to mitigate benzene formation in soft drinks. National regulations concerning maximum levels of benzene in drinking water and air were also presented.

  20. Experimental Study on Permeability of Concrete

    Science.gov (United States)

    Yang, Honglu; Liu, Rentai; Zheng, Zhuo; Liu, Haojie; Gao, Yan; Liu, Yankai

    2018-01-01

    To study the influencing factors on permeability of pervious concrete, by adding inorganic organic composite materials obtained experimental results show that different aggregate size, aggregate cement ratio of different, different water cement ratio on the permeability performance. The permeability of the concrete was tested by using the self - made permeable device. The experimental results showed that the permeation coefficient of the experiment was obtained and the factors influencing the permeability of the concrete were compared and analyzed. At the same time, the porosity of pervious concrete was measured, the influence of various variables on porosity was studied, and the influence of various factors on the permeability of voids was found. Finally, through comprehensive analysis of a variety of factors, the optimal water cement ratio is 0.28. At this time, the pervious performance of concrete is optimal.

  1. Benzene degradation in a denitrifying biofilm reactor : activity and microbial community composition

    NARCIS (Netherlands)

    van der Waals, Marcelle J.; Atashgahi, Siavash; da Rocha, Ulisses Nunes; van der Zaan, Bas M.; Smidt, Hauke; Gerritse, Jan

    2017-01-01

    Benzene is an aromatic compound and harmful for the environment. Biodegradation of benzene can reduce the toxicological risk after accidental or controlled release of this chemical in the environment. In this study, we further characterized an anaerobic continuous biofilm culture grown for more than

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

    NARCIS (Netherlands)

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

    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

  3. The role of CH $\\ldots $ interaction in the stabilization of benzene ...

    Indian Academy of Sciences (India)

    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 ...

  4. 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, ...

  5. Theoretical and experimental studies of elementary particles

    International Nuclear Information System (INIS)

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

    1991-01-01

    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

  6. Experimental Setups for Single Event Effect Studies

    OpenAIRE

    N. H. Medina; V. A. P. Aguiar; N. Added; F. Aguirre; E. L. A. Macchione; S. G. Alberton; M. A. G. Silveira; J. Benfica; F. Vargas; B. Porcher

    2016-01-01

    Experimental setups are being prepared to test and to qualify electronic devices regarding their tolerance to Single Event Effect (SEE). A multiple test setup and a new beam line developed especially for SEE studies at the São Paulo 8 UD Pelletron accelerator were prepared. This accelerator produces proton beams and heavy ion beams up to 107Ag. A Super conducting Linear accelerator, which is under construction, may fulfill all of the European Space Agency requirements to qualify electronic...

  7. Unleaded gasoline with reduction in benzene and aromatics

    International Nuclear Information System (INIS)

    Ahmed, I.

    2003-01-01

    The trend today is towards making gasoline more environment and human friendly or in other words making gasoline a really clean fuel. This paper covers the ill effects of benzene and aromatics and the driving force behind their reduction in gasoline worldwide. It addresses health concerns specifically, and the theme is unleaded gasoline without simultaneously addressing reduction in benzene and aromatics is more harmful. The paper cites worldwide case studies, and also the World Bank (WB), Government of Pakistan (GoP), and United Nations (UN) efforts in this area in Pakistan. (author)

  8. Experimental studies of gravitation and feebler forces

    International Nuclear Information System (INIS)

    Cowsik, R.

    1993-01-01

    The theoretical motivations and the experimental context pertaining to the recent experimental studies of the Weak equivalence Principle and the open-quotes Fifth Forceclose quotes are reviewed briefly. With such a backdrop, the innovative design and the technical details of the several new experiments in this area are presented with a special emphasis on the experiments underway at Gauribidanur, situated on the Deccan Plateau. These experiments jointly rule out the existence of any new forces coupling to baryon or lepton number with a coupling greater than about 10 -4 of gravitation per a.m.u. at ranges of about 0.5m and longer. In a few years the author hopes to test the weak equivalence principle with sensitivity exceeding 10 -13

  9. 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)

  10. Experimental study of natural circulation circuit

    International Nuclear Information System (INIS)

    Lemos, Wanderley F.; Su, Jian; Faccini, Jose L.H.

    2011-01-01

    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)

  11. 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

  12. Comparison of personal air benzene and urine t,t-muconic acid as a benzene exposure surrogate during turnaround maintenance in petrochemical plants.

    Science.gov (United States)

    Koh, Dong-Hee; Lee, Mi-Young; Chung, Eun-Kyo; Jang, Jae-Kil; Park, Dong-Uk

    2018-04-12

    Previous studies have shown that biomarkers of chemicals with long half-lives may be better surrogates of exposure for epidemiological analyses, leading to less attenuation of the exposure-disease association, than personal air samples. However, chemicals with short half-lives have shown inconsistent results. In the present study, we compared pairs of personal air benzene and its short-half-life urinary metabolite trans,trans-muconic acid (t,t-MA), and predicted attenuation bias of theoretical exposure-disease association. Total 669 pairs of personal air benzene and urine t,t-MA samples were taken from 474 male workers during turnaround maintenance operations held in seven petrochemical plants. Maintenance jobs were classified into 13 groups. Variance components were calculated for personal air benzene and urine t, t-MA separately to estimate the attenuation of the theoretical exposure-disease association. Personal air benzene and urine t, t-MA showed similar attenuation of the theoretical exposure-disease association. Analyses for repeated measurements showed similar results, while in analyses for values above the limits of detection (LODs), urine t, t-MA showed less attenuation of the theoretical exposure-disease association than personal air benzene. Our findings suggest that there may be no significant difference in attenuation bias when personal air benzene or urine t,t-MA is used as a surrogate for benzene exposure.

  13. 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...

  14. Utilization of alternative fuels and materials in cement kiln towards emissions of benzene, toluene, ethyl-benzene and xylenes (BTEX)

    OpenAIRE

    Muliane Ulfi; Lestari Puji

    2018-01-01

    Co-processing in cement industry has benefits for energy conservation and waste recycling. Nevertheless, emissions of benzene, toluene, ethyl-benzene, and xylenes (BTEX) tend to increase compared to a non co-processing kiln. A study was conducted in kiln feeding solid AFR (similar to municipal solid waste, MSW) having production capacity 4600-ton clinker/day (max. 5000 ton/day) and kiln feeding biomass having production capacity 7800-ton clinker/day (max. 8000 ton/day). The concentration of V...

  15. Experimental studies on mushroom and pollen drying

    Energy Technology Data Exchange (ETDEWEB)

    Midilli, Adnan; Olgun, Hayati; Ayhan, Teoman [Karadeniz Technical Univ., Mechanical Engineering Dept., Trabzon (Turkey)

    1999-07-01

    In this study, drying periods of mushrooms and pollens (for Anzer honey) were investigated. The experiments of mushrooms were carried out under both laboratory and shady- and sunny-atmospheric conditions and those of pollens were conducted in the drying cupboard heated by electric heater and under sunny atmospheric conditions. The temperature of the drying cupboard was regulated at 45degC during the drying experiment of pollen. The mass loss of pollens and the temperature of each shelf including pollens in the drying cupboard were measured. Drying curves of mushrooms and pollens for each experiment and the variation of the mass change ratio, the moisture ratio of pollens and the temperatures in the shelves with drying time were presented, respectively. Furthermore, their equations of drying curves and the average experimental uncertainty ratios were calculated based on the experimental results. It was concluded that mushrooms can be dried in the cupboards by using hot air at 50degC in a time period of 5-6 h, and the dried must be protected in vacuum, and the pollens also must be dried at temperatures between 40 and 45degC in a time period of 2.5-3 h without their losing the colour, flavour, smell and structure. The average experimental uncertainty ratio of mushrooms and pollens during the drying process were calculated to be 22 and 18% respectively. (Author)

  16. Experimental percolation studies of random networks

    Science.gov (United States)

    Feinerman, A.; Weddell, J.

    2017-06-01

    This report establishes an experimental method of studying electrically percolating networks at a higher resolution than previously implemented. This method measures the current across a conductive sheet as a function of time as elliptical pores are cut into the sheet. This is done utilizing a Universal Laser System X2-600 100 W CO2 laser system with a 76 × 46 cm2 field and 394 dpc (dots/cm) resolution. This laser can cut a random system of elliptical pores into a conductive sheet with a potential voltage applied across it and measures the current versus time. This allows for experimental verification of a percolation threshold as a function of the ellipse's aspect ratio (minor/major diameter). We show that as an ellipse's aspect ratio approaches zero, the percolation threshold approaches one. The benefit of this method is that it can experimentally measure the effect of removing small pores, as well as pores with complex geometries, such as an asterisk from a conductive sheet.

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

    International Nuclear Information System (INIS)

    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 B6C3F 1 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. At the highest exposure concentration, rats exhaled approximately half of the internal dose retained at the end of the 6-hr exposure as benzene; mice exhaled only 15% as benzene. Mice were able to convert more of the inhaled benzene to metabolites than were rats. In addition, mice metabolized more of the benzene by pathways leading to the putative toxic metabolites, benzoquinone and muconaldehyde, than did rats. In both rats and mice, the effect of increasing dose, administered orally or by inhalation, was to increase the proportion of the total metabolites that were the products of detoxification pathways relative to the products of pathways leading to putative toxic metabolites. This indicates low-affinity, high-capacity pathways for detoxification and high-affinity, low-capacity pathways leading to putative toxic metabolites. If the results of rodent studied performed at high doses were used to assess the health risk at low-dose exposures to benzene, the toxicity of benzene would be underestimated

  18. Benzene-Induced Aberrant miRNA Expression Profile in Hematopoietic Progenitor Cells in C57BL/6 Mice.

    Science.gov (United States)

    Wei, Haiyan; Zhang, Juan; Tan, Kehong; Sun, Rongli; Yin, Lihong; Pu, Yuepu

    2015-11-12

    Benzene is a common environmental pollutant that causes hematological alterations. MicroRNAs (miRNAs) may play a role in benzene-induced hematotoxicity. In this study, C57BL/6 mice showed significant hematotoxicity after exposure to 150 mg/kg benzene for 4 weeks. Benzene exposure decreased not only the number of cells in peripheral blood but also hematopoietic progenitor cells in the bone marrow. Meanwhile, RNA from Lin(-) cells sorted from the bone marrow was applied to aberrant miRNA expression profile using Illumina sequencing. We found that 5 miRNAs were overexpressed and 45 miRNAs were downregulated in the benzene exposure group. Sequencing results were confirmed through qRT-PCR. Furthermore, we also identified five miRNAs which significantly altered in Lin(-)c-Kit⁺ cells obtained from benzene-exposed mice, including mmu-miR-34a-5p; mmu-miR-342-3p; mmu-miR-100-5p; mmu-miR-181a-5p; and mmu-miR-196b-5p. In summary, we successfully established a classical animal model to induce significant hematotoxicity by benzene injection. Benzene exposure may cause severe hematotoxicity not only to blood cells in peripheral circulation but also to hematopoietic cells in bone marrow. Benzene exposure also alters miRNA expression in hematopoietic progenitor cells. This study suggests that benzene induces alteration in hematopoiesis and hematopoiesis-associated miRNAs.

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

    International Nuclear Information System (INIS)

    Palmgren, F.; Hansen, A.B.; Berkowicz, R.; Skov, H.

    2001-01-01

    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. (Author)

  20. MGMT hypomethylation is associated with DNA damage in workers exposed to low-dose benzene.

    Science.gov (United States)

    Li, Jie; Zhang, Xinjie; He, Zhini; Sun, Qing; Qin, Fei; Huang, Zhenlie; Zhang, Xiao; Sun, Xin; Liu, Linhua; Chen, Liping; Gao, Chen; Wang, Shan; Wang, Fangping; Li, Daochuan; Zeng, Xiaowen; Deng, Qifei; Wang, Qing; Zhang, Bo; Tang, Huanwen; Chen, Wen; Xiao, Yongmei

    2017-07-01

    This study aims to assess the effects of low-dose benzene on DNA damage and O 6 -methylguanine-DNA methyltransferase (MGMT) methylation in occupational workers. We recruited 96 nonsmoking male petrochemical industry workers exposed to low-dose benzene and 100 matched control workers. Urinary S-phenylmercapturic acid (SPMA) and S-benzylmercapturic acid (SBMA) were measured for indicating internal exposure of benzene and toluene. The degree of DNA damage was determined by the Comet assay. The levels of MGMT methylation were detected quantitatively by bisulphite-PCR pyrosequencing assay. The benzene-exposed workers had significantly higher levels of urinary SPMA, degree of DNA damage but decreased MGMT methylation than the controls (all p benzene-exposed workers and the controls. In all participants, MGMT methylation was negatively associated with the urinary SPMA and the degree of DNA damage, indicating that epigenetic regulation might be involved in response to low-dose benzene exposure-induced genetic damage. MGMT methylation could be a potent biomarker associated with low-dose benzene exposure and benzene-induced DNA damage.

  1. Alternatives for Benzene in the Extraction of Bitumen Fume from Exposure Sample Media.

    Science.gov (United States)

    Sutter, Benjamin; Ravera, Christel; Hussard, Caroline; Langlois, Eddy

    2016-01-01

    Benzene is frequently used to extract collected bitumen fumes from personal sampler substrates. However, this solvent is particularly dangerous because of its carcinogenicity (group 1 of the International Agency for Research on Cancer classification). Therefore, to prevent the exposure of laboratory technicians to benzene during the fume extraction step from samplers, a compromise had to be found to identify a less toxic solvent with the same extraction capacity. To compare the extraction capacities of selected solvents, bitumen fumes were generated in the laboratory from three different batches of road surfacing bitumen collected on dedicated bitumen fume samplers. The samplers were then extracted by benzene and the solvents tested. Of 11 selected solvents less toxic than benzene and used in studies on bitumen and bitumen fume analyses, n-hexane and n-heptane were identified as alternatives to benzene. In particular, the results demonstrated that n-heptane was the best candidate solvent for benzene replacement, due to its extraction efficiency comparable to benzene for the three bitumen fumes tested and its low toxicity, which is highly compatible with benzene replacement. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  2. Antioxidant Compounds in Traditional Indian Pickles May Prevent the Process-Induced Formation of Benzene.

    Science.gov (United States)

    Kharat, Mahesh M; Adiani, Vanshika; Variyar, Prasad; Sharma, Arun; Singhal, Rekha S

    2016-01-01

    Pickles in the Indian market contain ascorbic acid from the raw material used and benzoate as an added preservative that are involved in the formation of benzene in soft drinks. In this work, 24 market pickle samples were surveyed for benzene content, as well as its precursors and other constituents that influence its formation. The analysis showed that pickle samples were high in acid content (low pH) and showed significant amount of ascorbic acid, minerals (Cu and Fe), and benzoic acid present in them. Also, most samples exhibited high antioxidant activity that might be attributed to the ingredients used, such as fruits and spices. The solid-phase microextraction headspace gas chromatography-mass spectrometry method was developed in-house for benzene analysis. Eleven of 24 samples had benzene, with the highest concentration of 4.36 ± 0.82 μg of benzene per kg of pickle for a lime pickle that was also reported to have highest benzoic acid and considerably less hydroxyl radical ((•)OH) scavenging activity. However, benzene levels for all 11 samples were considerably below the World Health Organization regulatory limit of 10 μg/kg for benzene in mineral water. Studies on model systems revealed that the high antioxidant activity of Indian pickles may have had a strong inhibitory effect on benzene formation.

  3. Modeling benzene permeation through drinking water high density polyethylene (HDPE) pipes.

    Science.gov (United States)

    Mao, Feng; Ong, Say Kee; Gaunt, James A

    2015-09-01

    Organic compounds such as benzene, toluene, ethyl benzene and o-, m-, and p-xylene from contaminated soil and groundwater may permeate through thermoplastic pipes which are used for the conveyance of drinking water in water distribution systems. In this study, permeation parameters of benzene in 25 mm (1 inch) standard inside dimension ratio (SIDR) 9 high density polyethylene (HDPE) pipes were estimated by fitting the measured data to a permeation model based on a combination of equilibrium partitioning and Fick's diffusion. For bulk concentrations between 6.0 and 67.5 mg/L in soil pore water, the concentration-dependent diffusion coefficients of benzene were found to range from 2.0×10(-9) to 2.8×10(-9) cm2/s while the solubility coefficient was determined to be 23.7. The simulated permeation curves of benzene for SIDR 9 and SIDR 7 series of HDPE pipes indicated that small diameter pipes were more vulnerable to permeation of benzene than large diameter pipes, and the breakthrough of benzene into the HDPE pipe was retarded and the corresponding permeation flux decreased with an increase of the pipe thickness. HDPE pipes exposed to an instantaneous plume exhibited distinguishable permeation characteristics from those exposed to a continuous source with a constant input. The properties of aquifer such as dispersion coefficients (DL) also influenced the permeation behavior of benzene through HDPE pipes.

  4. 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

  5. 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. Note...

  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 a...

  7. 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 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 to...

  9. Experimental study of rf pulsed heating

    CERN Document Server

    Laurent, L; Nantista, C; Dolgashev, V; Higashi, Y; Aicheler, M; Tantawi, S; Wuensch, W

    2011-01-01

    Cyclic thermal stresses produced by rf pulsed heating can be the limiting factor on the attainable reliable gradients for room temperature linear accelerators. This is especially true for structures that have complicated features for wakefield damping. These limits could be pushed higher by using special types of copper, copper alloys, or other conducting metals in constructing partial or complete accelerator structures. Here we present an experimental study aimed at determining the potential of these materials for tolerating cyclic thermal fatigue due to rf magnetic fields. A special cavity that has no electric field on the surface was employed in these studies. The cavity shape concentrates the magnetic field on one flat surface where the test material is placed. The materials tested in this study have included oxygen free electronic grade copper, copper zirconium, copper chromium, hot isostatically pressed copper, single crystal copper, electroplated copper, Glidcop (R), copper silver, and silver plated co...

  10. Laparoscopic ureterocalicostomy in pigs - experimental study

    Directory of Open Access Journals (Sweden)

    Paulo Fernando de Oliveira Caldas

    2015-07-01

    Full Text Available This study aimed to evaluated laparoscopic ureterocalicostomy as treatment of experimental ureteropelvic junction (UPJ obstruction in pigs. Ten male Large White pigs weighting approximately 28.4 (±1.43 kg were used in the current study. The UPJ obstruction was created laparoscopically by double-clipping of the left ureter. After 14 days the animals underwent laparoscopic ureterocalicostomy f The animals were sacrificed for subsequent retrograde pyelography in order to assess the anastomotic patency on the 28th day. The laparoscopic procedure for experimental obstruction of UPJ was successfully performed in all animals, as well as the laparoscopic ureterocalicostomy. There was intestinal iatrogenic injury in one animal. Satisfactory UPJ patency was noted in 75% of the animals. There was no stenosis of the proximal anastomosis between the ureter and the lower pole of the kidney in 37.5%, mild stenosis in 37.5% and severe stenosis in 25% of the animals. The laparoscopic approach for reestablishment he urinary flow by ureterocalicostomy was feasible in the porcine model. The ascending pyelography revealed satisfactory results of the laparoscopic ureterocalicostomy

  11. Experimental study of unsteady thermally stratified flow

    International Nuclear Information System (INIS)

    Lee, Sang Jun; Chung, Myung Kyoon

    1985-01-01

    Unsteady thermally stratified flow caused by two-dimensional surface discharge of warm water into a oblong channel was investigated. Experimental study was focused on the rapidly developing thermal diffusion at small Richardson number. The basic objectives were to study the interfacial mixing between a flowing layer of warm water and an underlying body of cold water and to accumulate experimental data to test computational turbulence models. Mean velocity field measurements were carried out by using NMR-CT(Nuclear Magnetic Resonance-Computerized Tomography). It detects quantitative flow image of any desired section in any direction of flow in short time. Results show that at small Richardson number warm layer rapidly penetrates into the cold layer because of strong turbulent mixing and instability between the two layers. It is found that the transfer of heat across the interface is more vigorous than that of momentum. It is also proved that the NMR-CT technique is a very valuable tool to measure unsteady three dimensional flow field. (Author)

  12. Vascularized nerve grafts: an experimental study.

    Science.gov (United States)

    Donzelli, Renato; Capone, Crescenzo; Sgulò, Francesco Giovanni; Mariniello, Giuseppe; Maiuri, Francesco

    2016-08-01

    The aim of this study is to define an experimental model in order to promote the functional recovery of the nerves using grafts with vascular support (Vascular Nerve Grafts - VNG). The aim of this study is to define, on an experimental model in normal recipient bed, whether the functional recovery with VNG is superior to that obtained non-vascularized graft (NNG). Twenty male rabbits, which underwent dissection of sciatic nerve, were later treated by reinnervation through an autograft. In 10 animals the reconstruction of sciatic nerve was realized with VNG; in 10 control animals the reconstruction of sciatic nerve was realized with NNG. The VNG group showed a better axonal organization and a significantly higher number of regenerated axons in the early phases (after 30 days) than the NNG group, whereas the difference in the axonal number at day 90 was less significant; besides, the axon diameter and the myelin thickness were not significantly improved by VNG group. Our data suggests that the use of VNG leads to a faster regeneration process and a better functional recovery, although the final results are comparable to those of the NNG. VNG improve the quality of the axonal regeneration (axonal diameter and Schwann cells), although the increase in the axonal number is not significant and does not improve the long-term functional outcome.

  13. Spectroscopic Studies of Fluorescence Effects in Bioactive 4-(5-Heptyl-1,3,4-Thiadiazol-2-yl)Benzene-1,3-Diol and 4-(5-Methyl-1,3,4-Thiadiazol-2-yl)Benzene-1,3-Diol Molecules Induced by pH Changes in Aqueous Solutions.

    Science.gov (United States)

    Matwijczuk, Arkadiusz; Kluczyk, Dariusz; Górecki, Andrzej; Niewiadomy, Andrzej; Gagoś, Mariusz

    2017-07-01

    This paper presents the results of stationary fluorescence spectroscopy and time-resolved spectroscopy analyses of two 1,3,4-thiadiazole analogues, i.e. 4-(5-methyl-1,3,4-thiadiazol-2-yl)benzene-1,3-diol (C1) and 4-(5-heptyl-1,3,4-thiadiazol-2-yl)benzene-1,3-diol (C7) in an aqueous medium containing different concentrations of hydrogen ions. An interesting dual florescence effect was observed when both compounds were dissolved in aqueous solutions at pH below 7 for C1 and 7.5 for C7. In turn, for C1 and C7 dissolved in water at pH higher than the physiological value (mentioned above), single fluorescence was only noted. Based on previous results of investigations of the selected 1,3,4-thiadiazole compounds, it was noted that the presented effects were associated with both conformational changes in the analysed molecules and charge transfer (CT) effects, which were influenced by the aggregation factor. However, in the case of C1 and C7, the dual fluorescence effects were visible in a higher energetic region (different than that observed in the 1,3,4-thiadiazoles studied previously). Measurements of the fluorescence lifetimes in a medium characterised by different concentrations of hydrogen ions revealed clear lengthening of the excited-state lifetime in a pH range at which dual fluorescence effects can be observed. An important finding of the investigations presented in this article is the fact that the spectroscopic effects observed not only are interesting from the cognitive point of view but also can help in development of an appropriate theoretical model of molecular interactions responsible for the dual fluorescence effects in the analysed 1,3,4-thiadiazoles. Furthermore, the study will clarify a broad range of biological and pharmaceutical applications of these compounds, which are more frequently used in clinical therapies. Graphical Abstract Upper left corner - C7 molecule at high pH, right upper corner - fluorescence emission spectrum for C7 dissolved in H

  14. 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.

  15. Experimental studies of the magnetized friction force

    International Nuclear Information System (INIS)

    Fedotov, A. V.; Litvinenko, V. N.; Gaalnander, B.; Lofnes, T.; Ziemann, V.; Sidorin, A.; Smirnov, A.

    2006-01-01

    High-energy electron cooling, presently considered as an essential tool for several applications in high-energy and nuclear physics, requires an accurate description of the friction force which ions experience by passing through an electron beam. Present low-energy electron coolers can be used for a detailed study of the friction force. In addition, parameters of a low-energy cooler can be chosen in a manner to reproduce regimes expected in future high-energy operation. Here, we report a set of dedicated experiments in CELSIUS aimed at a detailed study of the magnetized friction force. Some results of the accurate comparison of experimental data with the friction force formulas are presented

  16. Experimental Studies of quasi-fission reactions

    International Nuclear Information System (INIS)

    Back, B.B.

    1989-01-01

    A large number of recent experimental studies have shown that a substantial fraction of the total reaction cross section in heavy-ion reactions is found in fission-like processes, which do not result from the fission decay of a completely fused system. Following the suggestion of Swiatecki such processes, which represents a complete relaxation of the relative kinetic energy and a substantial amount of net mass transfer between the two fragments, are denoted quasi-fission reactions. They are distinct from compound fission reactions by bypassing the stage of a completely fused system. This typically means that they are associated with short reaction times, which results in several measurable characteristics such as broken forward-backward symmetries, large anisotropies of the angular distributions and increased widths of the fragment mass distributions. The distinction between quasi-fission and deep inelastic reactions is less stringent and has the character of a gradual evolution from one reaction type to the other, as found also as quasi-elastic reaction evolves into deeply inelastic processes as a function of the total kinetic energy loss. In the present paper some of the experimental data characterizing quasi-fission reactions are reviewed and discussed. (author)

  17. Overview of experimental studies on vapor explosions

    International Nuclear Information System (INIS)

    Moriyama, Kiyofumi; Yamano, Norihiro; Maruyama, Yu; Kudo, Tamotsu; Sugimoto, Jun

    1994-12-01

    Experimental studies of vapor explosions were overviewed and currently available knowledge was summarized with emphasis on the large scale experiments. Since 1970s, quite a few large scale experiments have been performed, which have included several types such as pin geometry experiments simulating the early stages of severe accidents in nuclear reactors, and melt-coolant interaction experiments with drop/jet geometry or stratified geometry simulating the phenomena expected to take place after a large scale core melt-down. According to previous experimental results, following facts are clarified ; spontaneous explosions are not likely with saturated coolant and/or with high pressures ; the energy conversion ratio in large scale systems is in the range 0.1∼several percents ; if the coolant is sodium generally benign interaction is expected compared with the case of water coolant ; etc. Recently, accompanied with the development of numerical simulation codes for vapor explosions, considerable efforts are devoted into premixing experiments and one dimensional geometry experiments oriented to provide data for the comparison with numerical simulations. (author) 87 refs

  18. Experimental study on low pressure flow instability

    International Nuclear Information System (INIS)

    Jiang Shengyao; Wu Xinxin; Wu Shaorong; Bo Jinhai; Zhang Youjie

    1997-05-01

    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.)

  19. Metabolic Desynchronization in Critical Conditions: Experimental Study

    Directory of Open Access Journals (Sweden)

    G. V. Livanov

    2006-01-01

    Full Text Available Objective. To conduct an experimental study of the impact of the time of administration of succinic acid preparations on central nervous system (CNS function and gas exchange while simulating metabolic therapy for severe poisoning by ethyl alcohol. The study was performed on 74 male albino rats weighing 140—180 g. Acute severe and very severe intoxication was simulated, by intraabdominally administering 30% ethanol to the rats. Cytoflavin was used to simulate experimental therapy. The rate of gas exchange was estimated by the oxygen uptake determined by the closed chamber method in a Regnault apparatus (Germany. Spontaneous bioelectrical activity was recorded in the frontooccipital lead by the routine procedure. External pain stimulation and rhythmical photostimulation were employed to evaluate cerebral responsiveness. Heterodirectional EEG changes in the «early» and «late» administration of succinate were not followed by the similar alterations of gas exchange: oxygen consumption in both the «early» and «late» administration of succinate remained significantly lower than in the control animals. With the late administration of succinate to the animals with mixed (toxic and hypoxic coma, the so-called discrepancy between the noticeably increased energy production and brutally diminished metabolism occurred. It may be just the pathological mechanism that was the basis for higher mortality in the late succinate administration group. The findings and their analysis make it possible to advance a hypothesis that succinate may cause metabolic desynchronization if activation of metabolic processes takes place under severe tissue respiratory tissue depression. In these cases, there is a severe damage to tissue and chiefly the brain. This manifests itself as EEG epileptiform activity splashes preceding the animals’ death. Therefore, resuscitation aimed at restoring the transport of oxygen and its involvement in tissue energy processes should

  20. Contribution to the experimental study of the hydraulic jump in ...

    African Journals Online (AJOL)

    The purpose of this study is to study experimentally the hydraulic jump evolving in a symmetric trapezoidal channel with a positive slope, requires the use of an experimental protocol, and to find experimental relations linking the characteristics of the formed projection. The experimental study investigated the variation of the ...

  1. Reactions between aromatic hydrocarbons and heterocycles: covalent and proton-bound dimer cations of benzene/pyridine.

    Science.gov (United States)

    El-Shall, M Samy; Ibrahim, Yehia M; Alsharaeh, Edreese H; Meot-Ner Mautner, Michael; Watson, Simon P

    2009-07-29

    Despite the fact that benzene (Bz) and pyridine (Py) are probably the most common and extensively studied organic molecules, the observation of a covalent adduct in the ionized benzene/pyridine system has never been reported. This Article reports the first experimental and theoretical evidence of a covalent (Bz x Py)(*+) adduct that results from the reaction of Bz(*+) with pyridine or Py(*+) with benzene. These reactions are studied using mass-selected ion mobility, chemical reactivity, collisional dissociation, and ab initio calculations. The (Bz x Py)(*+) adduct does not exchange ligands with Bz to form Bz(2)(*+) or with Py to form (Py)(2)H(+) despite the strong bonds in these homodimers. The thermochemistry then suggests that the (Bz x Py)(*+) heterodimer is bonded covalently with a bonding energy of >33 kcal/mol. Correspondingly, ab initio calculations identify covalently bonded propeller-shaped isomers of (Bz x Py)(*+) with bonding energies of 31-38 kcal/mol, containing a C-N bond. The mobility of the (Bz x Py)(*+) adduct in helium is consistent with these covalent dimers. As to noncovalent adducts, the computations identify novel distonic hydrogen-bonded complexes (C(5)H(5)NH(+) x C(6)H(5)(*)) where the charge resides on one component (PyH(+)), while the radical site resides on the other component (C(6)H(5)(*)). Collisional dissociation suggests that the covalent and distonic dimers may interconvert at high energies. The most stable distonic (C(5)H(5)NH(+) x C(6)H(5)(*)) complex contains a hydrogen bond to the phenyl radical carbon site with a calculated dissociation energy of 16.6 kcal/mol. This bond is somewhat stronger than the NH(+) x pi hydrogen bonds of PyH(+) to the pi system of the phenyl radical and of the benzene molecule. For this NH(+) x pi bond in the PyH(+) x Bz dimer, the measured binding energy is 13.4 kcal/mol, and ab initio calculations identify two T-shaped isomers with the NH(+) pointing to the center of the benzene ring or to the

  2. Experimental study of capillary-assisted evaporators

    Energy Technology Data Exchange (ETDEWEB)

    Sabir, H.M.; ElHag, Y.B.M.; Benhadj-Djilali, R. [Faculty of Engineering, Kingston University, Friars Avenue, London SW15 3DW (United Kingdom)

    2008-07-01

    The paper presents the results of experimental work aimed at studying the effect of porous layer parameters on the thermal performance of water evaporators. The results show that there are optimum particle sizes that are associated with maximum boiling heat rates and heat transfer coefficients. The results also show that the layer thickness has monotonic effect on the evaporators' performance but its impact is less pronounced compared to that of the particle size. The trends are explained in terms of the contradicting effects that exist within the layer. The research also showed that the effect of the heat load, represented by temperature and velocity of the load air, was negligible. Boiling heat transfer coefficients of up to 5 kW/m{sup 2} C were achieved. (author)

  3. Pulley reconstruction with different materials: experimental study.

    Science.gov (United States)

    Oruç, Melike; Ulusoy, M Gürhan; Kankaya, Yüksel; Koçer, Uğur; Serbetçi, Kemal; Hasrc, Nesrin

    2008-08-01

    The digital fibroosseous pulley system is essential for optimum function of the flexor tendons and the continuation of normal hand functions. Different materials have been used for pulley reconstruction in the literature but the ideal material is still controversial. In this study, after the excision of the A2 pulley, pulley reconstructions were performed by using acellular dermal matrix, solvent dehydrated bovine pericardium, fascia lata, and free tendon graft in the rabbit model. The animals were killed at the 8th and 12th weeks and subjected to biomechanical testing. Tendon excursion and work of flexion values were calculated for each digit of the rabbits. As a result, all the reconstructed pulleys were functioning well without a statistically significant difference between the experimental groups. Pulleys reconstructed with acellular dermal matrix and solvent-dehydrated bovine pericardium appear to have the potential to function as effective pulley substitutes.

  4. [Endodontics in horses. An experimental study].

    Science.gov (United States)

    Garcia, F; Sanromán, F; Llorens, M P

    1990-04-01

    A total of 44 experimental endodontic treatments were performed in incisors of eight horses of different ages. Four different endodontic pastes were used: Cloropercha, AH26 De Trey, Eugenol-Endometasone, and Universal N2. Gutta-percha points were also included in the last two treatments. Access to the pulp cavity of incisors was gained through their vestibular and occlusal faces. Holes drilled in vestibular faces were sealed with composite and those drilled in occlusal faces were sealed with Amalgama. Animals were observed during eighteen months at least after endodontics. Radiographic controls were done just after surgery and before slaughtering. Treated incisors and alveoli were studied histopathologically. During the experiment all animals were in good condition. They ate apparently without trouble, and neither clinical nor radiological signs were present.

  5. Experimental Study of Factors Affecting Soil Erodibility

    Science.gov (United States)

    Larionov, G. A.; Bushueva, O. G.; Gorobets, A. V.; Dobrovolskaya, N. G.; Kiryukhina, Z. P.; Krasnov, S. F.; Litvin, L. F.; Maksimova, I. A.; Sudnitsyn, I. I.

    2018-03-01

    The effect of different factors and preparation conditions of monofraction samples from the arable horizon of leached chernozem on soil erodibility and its relationship with soil tensile strength (STS) has been studied. The exposure of samples at 38°C reduces their erodibility by two orders of magnitude. The drying of samples, on the contrary, increases their erodibility. It has been shown that erodibility decreases during the experiment. It has been found that the inoculation of soil with yeast cultures ( Naganishia albida, Lipomyces tetrasporus) reliably increases the STS value in 1.5-1.9 times. The sterile soil is eroded more intensively than the unsterile soil: at 4.9 and 0.3 g/(m2 s), respectively. The drying of soil followed by wetting to the initial water content (30%) has no significant effect on the STS value in almost all experimental treatments.

  6. Experimental study of crossing angle collision

    International Nuclear Information System (INIS)

    Chen, T.; Rice, D.; Rubin, D.; Sagan, D.; Tigner, M.

    1993-05-01

    The non-linear coupling due to the beam-beam interaction with crossing angle has been studied. The major effect of a small (∼12mrad) crossing angle is to excite 5Q x ±Q s =integer coupling resonance family on large amplitude particles, which results in bad lifetime. On the CESR, a small crossing angle (∼2.4mr) was created at the IP and a reasonable beam-beam tune-shift was achieved. The decay rate of the beam is measured as a function of horizontal tune with and without crossing angle. The theoretical analysis, simulation and experimental measurements have a good agreement. The resonance strength as a function of crossing angle is also measured

  7. Experimental study of crossing angle collision

    International Nuclear Information System (INIS)

    Chen, T.; Rice, D.; Rubin, D.; Sagan, D.; Tigner, M.

    1993-01-01

    The non-linear coupling due to the beam-beam interaction with crossing angle has been studied. The major effect of a small (∼12mrad) crossing angle is to excite 5Q x ±Q s =integer coupling resonance family on large amplitude particles, which results in bad lifetime. On the CESR, a small crossing angle (∼2.4mr) was created at the IP and a reasonable beam-beam tune-shift was achieved. The decay rate of the beam is measured as a function of horizontal tune with and without crossing angle. The theoretical analysis, simulation and experimental measurements have a good agreement. The resonance strength as a function of crossing angle is also measured

  8. 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.

  9. Benzene electro-oxidation in a PEMFC for phenol and electricity cogeneration

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Rui; Ji, Baofeng; Yang, Weishen; Xin, Qin [State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, CAS, P.O. Box 110, 116023 Dalian (China); Song, Shuqin; Douvartzides, Savvas; Tsiakaras, Panagiotis [Department of Mechanical Engineering, School of Engineering, University of Thessalia, Pedion Areos, 383 34 Volos (Greece); Sun, Gongquan [Direct Alcohol Fuel Cell Lab, Dalian Institute of Chemical Physics, CAS, P.O. Box 110, 116023 Dalian (China)

    2005-11-09

    In the present investigation, the electrochemically-assisted oxidation of benzene in a H{sub 2}-O{sub 2} proton exchange membrane fuel cell (PEMFC), for electricity and phenol cogeneration is studied. Experiments were carried out in a PEMFC electrochemical reactor using Pd black as cathode electrocatalyst at 60 and 80{sup o}C, respectively and 1atm back pressure. Indeed, it was found that the only product detected under the examined experimental conditions was phenol. The online GC product analysis revealed that it is impossible to produce phenol when the fuel cell circuit is open (I=0) under all the examined experimental conditions. When the fuel cell circuit was closed, however, the phenol yield was found to follow a volcano-type dependence on the current of the external circuit. It was found that the maximum phenol yield was 0.35% at 100mA/cm{sup 2} at 80{sup o}C. At the same time, the PEMFC performance was also investigated during the phenol generation process. Furthermore, experiments with the rotating ring disc electrode (RRDE) technique showed that the intermediate oxidation product, i.e. H{sub 2}O{sub 2} existed during the oxygen electro-reduction process. The cyclic voltammograms showed that benzene was strongly adsorbed on the Pd surface, leading to a degradation of the PEMFC performance.

  10. Leukemia risk in caprolactam workers exposed to benzene.

    Science.gov (United States)

    Swaen, Gerard M H; Scheffers, Theo; de Cock, Johan; Slangen, Jos; Drooge, Hinkelien

    2005-01-01

    To investigate the leukemia risk in a group of benzene exposed workers. We conducted a retrospective cohort mortality study on 311 men who worked between January 1, 1951 and December 31, 1968 in a Caprolactam plant in the Netherlands. In the production of Caprolactam (the Nylon 6 monomer) pure benzene is used as an extracting agent and the workers at this plant have been exposed to substantial concentrations of benzene. The cohort was followed for mortality until January 1, 2001. The total mortality was below the expected number, which was mainly caused by a deficit of cardiovascular disease mortality. In the total group, there was one death from leukemia, compared with an expected number of 1.17. Despite the substantial exposures to benzene (on average 159 ppm-years per person) there was no indication for increased leukemia mortality within the cohort. We have applied earlier quantitative risk assessments to our cohort and conclude that some of these assessments overestimate the risk observed in our cohort of Caprolactam workers.

  11. Upstream petroleum industry glycol dehydrator benzene emissions status report

    International Nuclear Information System (INIS)

    1999-07-01

    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

  12. An experimental study of mixed convection

    International Nuclear Information System (INIS)

    Saez, Manuel

    1998-01-01

    The aim of our study is to establish a reliable data base for improving thermal-hydraulic codes, in the field of turbulent flows with buoyancy forces. The flow considered is mixed convection in the Reynolds and Richardson number range: Re=10 3 to 6*10 4 and Ri=10 -4 to 1. Experiments are carried out in an upward turbulent flow between vertical parallel plates at different wall temperatures. Part 1 gives a detailed data base of turbulent mixed flow of free and forced convection. Part II presents the installation and the calibration system intended for probes calibration. Part III describes the measurement technique (constant-temperature probe and cold-wire probe) and the method for measuring the position of the hot-wire anemometer from the wall surface. The measurement accuracy is within 0.001 mm in the present system. Part IV relates the development of a method for near wall measurements. This correction procedure for hot-wire anemometer close to wall has been derived on the basis of a two-dimensional numerical study. The method permits to obtain a quantitative correction of the wall influence on hot-wires and takes into account the velocity profile and the effects the wall material has on the heat loss. Part V presents the experimental data obtained in the channel in forced and mixed convection. Results obtained in the forced convection regime serve as a verification of the measurement technique close to the wall and give the conditions at the entrance of the test section. The effects of the buoyancy force on the mean velocity and temperature profiles are confirmed. The buoyancy strongly affects the flow structure and deforms the distribution of mean velocity. The velocity profiles are asymmetric. The second section of part V gives an approach of analytical wall functions with buoyancy forces, on the basis of the experimental data obtained in the test section. (author) [fr

  13. Benzene exposure assessed by metabolite excretion in Estonian oil shale mineworkers: influence of glutathione s-transferase polymorphisms

    DEFF Research Database (Denmark)

    Sørensen, Mette; Poole, Jason; Autrup, Herman

    2004-01-01

    Measurement of urinary excretion of the benzene metabolites S-phenylmercapturic acid (S-PMA) and trans,trans-muconic acid (t,t-MA) has been proposed for assessing benzene exposure, in workplaces with relatively high benzene concentrations. Excretion of S-PMA and t,t-MA in underground workers...... the last shift of the week. Personal benzene exposure was 114 +/- 35 mug/m(3) in surface workers (n = 15) and 190 +/- 50 mug/m(3) in underground workers (n = 15) in measurements made prior to the study. We found t,t-MA excretion to be significantly higher in underground workers after the end of shifts 1...... of benzene metabolites as biomarkers for assessment of exposure at modest levels and warrant for further investigations of health risks of occupational benzene exposure in shale oil mines....

  14. Simulation of the (vapor + liquid) equilibria of binary mixtures of benzene, cyclohexane, and hydrogen

    International Nuclear Information System (INIS)

    Carrero-Mantilla, J.

    2008-01-01

    Molecular simulations of the (vapor + liquid) equilibria (VLE) for benzene, cyclohexane, and (benzene + hydrogen) and (cyclohexane + hydrogen) were carried out using the Gibbs-ensemble Monte Carlo method with configurational bias. The Buckingham exponential six (exp-6) potential was used for the site-site interactions with no binary interaction parameters; benzene and cyclohexane were described with six interaction sites, and hydrogen with a single site. Simulation results, density, pressure, and vaporization enthalpy for benzene and cyclohexane were in reasonable agreement with experimental data, but critical pressures obtained from extrapolation of the VLE results did not match the experimental values. For (benzene + hydrogen) and (cyclohexane + hydrogen) mixtures mole fractions from simulation were compared with experimental data, the results for liquid phase were in closer agreement with experiment than the results for vapor phase. For the mixtures, results from the PSRK equation of state (PSRK-EOS) predicted the mole fractions for both phases, also vapor densities from molecular simulation were in close agreement with PSRK-EOS. Additionally, the Henry's law constant (K H ) for hydrogen was calculated in separate simulations using test particle insertions, and qualitative agreement with values from experimental VLE data was obtained. For the (benzene + hydrogen) system K H results from PSRK-EOS were closer to experiment than the results from simulation, but, for the (cyclohexane + hydrogen) system results from both methods had similar deviations from experiment. The results for pure substance and mixtures indicate that the combination of the three molecular models used for benzene, cyclohexane, and hydrogen is valid for the simulation of the VLE of their mixtures

  15. Reactions of benzene oxide, a reactive metabolite of benzene, with model nucleophiles and DNA.

    Science.gov (United States)

    Míčová, Kateřina; Linhart, Igor

    2012-10-01

    1. Reactivity of benzene oxide (BO), a reactive metabolite of benzene, was studied in model reactions with biologically relevant S- and N-nucleophiles by LC-ESI-MS. 2. Reaction with N-acetylcysteine (NAC) in aqueous buffer solutions gave N-acetyl-S-(6-hydroxycyclohexa-2,4-dien-1-yl)cysteine (pre-phenylmercapturic acid, PPhMA), which was easily dehydrated in acidic solutions to phenylmercapturic acid (PhMA). The yield of PPhMA + PhMA increased exponentially with pH up to 11% in the pH range from 5.5 to 11.4. 3. Primary 6-hydroxycyclohexa-2,4-dien-1-yl (HC) adducts were detected also in reactions of purine nucleosides and nucleotides under physiological conditions. After a vigorous acidic hydrolysis, all HC adducts were converted to corresponding phenyl purines, which were identified as 7-phenylguanine (7-PhG), 3-phenyladenine (3-PhA) and N(6)-phenyladenine (6-PhA). The yield of 7-PhG amounted to 14 ± 5 and 16 ± 7 ppm for 2'-deoxyguanosine and 2'-deoxyguanosine-5'-monophosphate, respectively, that of 6-PhA was 500 ± 70 and 455 ± 75 ppm with 2'-deoxyadenosine and 2'-deoxyadenosine-5'-phosphate, respectively, with only traces of 3-PhA. 4. Reactions with the DNA followed by acidic hydrolysis yielded 26 ± 11 ppm (mean ± SD; n = 9) of 7-PhG as the sole adduct detected. 5. In contrast to the reactions with S-nucleophiles, the reactivity of BO with nucleophilic sites in the DNA is very low and can therefore hardly account for a significant DNA damage caused by benzene.

  16. Benzene observations and source appointment in a region of oil and natural gas development

    Science.gov (United States)

    Halliday, Hannah Selene

    source, a diesel/compressed natural gas emissions source, a fugitive emissions source, and two sources that have the characteristics of a mix of fresh vehicle emissions and condensate fugitive emissions. 70% of the benzene measured at PAO on the PTR-QMS is attributed to fugitive emissions, primarily located to the SW of PAO. Comparing the PMF source attribution to source calculations done with a source array configured from the literature returns a contradictory result, with the expected sources indicting that aged vehicle emissions are the primary benzene source. However, analysis of the contradictory result indicates that the toluene to benzene ratio measured for PAO is much lower than the literature values, suggesting that the O&NG source emissions have a lower ratio of toluene to benzene than anticipated based on studies of other regions. Finally, we propose and investigate an alternative form of the source receptor model using a constrained optimization. Poor results of the proposed method are described with tests on a synthetic testing dataset, and further testing with the observation data from PAO indicate that the proposed method is not able to converge the best global solution to the system.

  17. Experimental study of rf pulsed heating

    Directory of Open Access Journals (Sweden)

    Lisa Laurent

    2011-04-01

    Full Text Available Cyclic thermal stresses produced by rf pulsed heating can be the limiting factor on the attainable reliable gradients for room temperature linear accelerators. This is especially true for structures that have complicated features for wakefield damping. These limits could be pushed higher by using special types of copper, copper alloys, or other conducting metals in constructing partial or complete accelerator structures. Here we present an experimental study aimed at determining the potential of these materials for tolerating cyclic thermal fatigue due to rf magnetic fields. A special cavity that has no electric field on the surface was employed in these studies. The cavity shape concentrates the magnetic field on one flat surface where the test material is placed. The materials tested in this study have included oxygen free electronic grade copper, copper zirconium, copper chromium, hot isostatically pressed copper, single crystal copper, electroplated copper, Glidcop®, copper silver, and silver plated copper. The samples were exposed to different machining and heat treatment processes prior to rf processing. Each sample was tested to a peak pulsed heating temperature of approximately 110°C and remained at this temperature for approximately 10×10^{6} rf pulses. In general, the results showed the possibility of pushing the gradient limits due to pulsed heating fatigue by the use of copper zirconium and copper chromium alloys.

  18. Theoretical and experimental studies of elementary physics

    International Nuclear Information System (INIS)

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

    1993-01-01

    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

  19. Benzene exposure in the shoemaking industry in China, a literature survey, 1978-2004.

    Science.gov (United States)

    Wang, Laiming; Zhou, Yimei; Liang, Youxin; Wong, Otto; Armstrong, Thomas; Schnatter, A Robert; Wu, Qiangen; Fang, Jinbin; Ye, Xibiao; Fu, Hua; Irons, Richard D

    2006-11-01

    trend of benzene exposure levels over the years, particularly after the introduction of the new lower OEL in 2002. Even though substantially lower when compared to levels in the past, current benzene exposure measurements from the literature review suggest that many facilities in the shoemaking industry in China have benzene concentrations that are still above the new OEL. The reported data, stratified by job, year and survey reason, can be used as part of the information and analysis for developing a job-exposure matrix in retrospective exposure assessment and thus may be part of the information used in developing historical exposure estimates in epidemiologic studies of shoe workers.

  20. Quasi-experimental study designs series-paper 9: collecting data from quasi-experimental studies.

    Science.gov (United States)

    Aloe, Ariel M; Becker, Betsy Jane; Duvendack, Maren; Valentine, Jeffrey C; Shemilt, Ian; Waddington, Hugh

    2017-09-01

    To identify variables that must be coded when synthesizing primary studies that use quasi-experimental designs. All quasi-experimental (QE) designs. When designing a systematic review of QE studies, potential sources of heterogeneity-both theory-based and methodological-must be identified. We outline key components of inclusion criteria for syntheses of quasi-experimental studies. We provide recommendations for coding content-relevant and methodological variables and outlined the distinction between bivariate effect sizes and partial (i.e., adjusted) effect sizes. Designs used and controls used are viewed as of greatest importance. Potential sources of bias and confounding are also addressed. Careful consideration must be given to inclusion criteria and the coding of theoretical and methodological variables during the design phase of a synthesis of quasi-experimental studies. The success of the meta-regression analysis relies on the data available to the meta-analyst. Omission of critical moderator variables (i.e., effect modifiers) will undermine the conclusions of a meta-analysis. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Monitoring benzene formation from benzoate in model systems by proton transfer reaction-mass spectrometry

    Science.gov (United States)

    Aprea, Eugenio; Biasioli, Franco; Carlin, Silvia; Märk, Tilmann D.; Gasperi, Flavia

    2008-08-01

    The presence of benzene in food and in particular in soft drinks has been reported in several studies and should be considered in fundamental investigations about formation of this carcinogen compound as well as in quality control. Proton transfer reaction-mass spectrometry (PTR-MS) has been used here for rapid, direct quantification of benzene and to monitor its formation in model systems related to the use of benzoate, a common preservative, in presence of ascorbic acid: a widespread situation that yields benzene in, e.g., soft drinks and fruit juices. Firstly, we demonstrate here that PTR-MS allows a rapid determination of benzene that is in quantitative agreement with independent solid phase micro-extraction/gas chromatography (SPME/GC) analysis. Secondly, as a case study, the effect of different sugars (sucrose, fructose and glucose) on benzene formation is investigated indicating that they inhibit its formation and that this effect is enhanced for reducing sugars. The sugar-induced inhibition of benzene formation depends on several parameters (type and concentration of sugar, temperature, time) but can be more than 80% in situations that can be expected in the storage of commercial soft drinks. This is consistent with the reported observations of higher benzene concentrations in sugar-free soft drinks.

  2. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Increased leukemia-associated gene expression in benzene-exposed workers

    Science.gov (United States)

    Li, Keqiu; Jing, Yaqing; Yang, Caihong; Liu, Shasha; Zhao, Yuxia; He, Xiaobo; Li, Fei; Han, Jiayi; Li, Guang

    2014-01-01

    Long-term exposure to benzene causes several adverse health effects, including an increased risk of acute myeloid leukemia. This study was to identify genetic alternations involved in pathogenesis of leukemia in benzene-exposed workers without clinical symptoms of leukemia. This study included 33 shoe-factory workers exposed to benzene at levels from 1 ppm to 10 ppm. These workers were divided into 3 groups based on the benzene exposure time, 1- benzene exposure history were recruited as controls. Cytogenetic analysis using Affymetrix Cytogenetics Array found copy-number variations (CNVs) in several chromosomes of benzene-exposed workers. Expression of targeted genes in these altered chromosomes, NOTCH1 and BSG, which play roles in leukemia pathogenesis, was further examined using real-time PCR. The NOTCH1 mRNA level was significantly increased in all 3 groups of workers, and the NOTCH1 mRNA level in the 12- benzene-exposed workers. PMID:24993241

  4. 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.

  5. Mechanisms of Laser-Induced Reactions of Stacked Benzene Molecules: A Semiclassical Dynamics Simulation and CASSCF Calculation

    OpenAIRE

    Shu, Kunxian; Zhao, Jie; Yuan, Shuai; Dou, Yusheng; Lo, Glenn V.

    2014-01-01

    The response to ultrashort laser pulses of two stacked benzene molecules has been studied by semiclassical dynamics simulation; two typical pathways were found following excitation of one of the benzene molecules by a 25 fs (FWHM), 4.7 eV photon. With a fluence of 40.49 J/m2, the stacked molecules form a cyclobutane benzene dimer; the formation of the two covalent bonds linking two benzenes occurs asynchronously after the excimer decays to electronic ground state. With a fluence of 43.26 J/m2...

  6. Lipid Peroxidation in Brain Injury (Experimental Study

    Directory of Open Access Journals (Sweden)

    V. N. Yelsky

    2009-01-01

    Full Text Available Objective: to study the general mechanisms responsible for the formation and stepwise development of the endogenous intoxication syndrome in the injury. Material and methods. One hundred and thirty animals with experimental brain injury (a blow upon the calvarium delivered by a free weight falling were examined to study the pro- and antioxidant systems, the enzymatic activity in the blood and brain tissue homogenates; the markers of endogenous intoxication, such as medium-weight molecules, were determined. According to the neurological deficit scale developed by A. Ya. Yevtushenko (1989, the animals were divided into 2 groups: 1 those with a good (compensated posttraumatic course and 2 those with a poor (decompensated one. A package of the applied statistical programs «STADIA.6.1/prof» and «STATISTIKA» was employed. Results. Brain injury was used as an example to show how the posttraumatic endogenous intoxication syndrome developed. The latter developed on the cascade principle with the stepwise involvement of the homeostatic systems and with the more aggravated injury. The syndrome is determined by the initiation of processes of lipid peroxidation with the accumulation of its products and by the exhausted spares of antioxidant systems. This leads to hyperenzymemia (the enhanced activity of cathepsin D, acid phosphatase in the brain tissues and blood and to the blood accumulation of toxic substances (medium-weight molecules (toxemia. Key words: posttraumatic endogenous intoxication syndrome, lipid peroxidation, brain injury.

  7. 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

  8. Occupational exposure to carcinogens: Benzene, pesticides and fibers (Review).

    Science.gov (United States)

    Falzone, Luca; Marconi, Andrea; Loreto, Carla; Franco, Sabrina; Spandidos, Demetrios A; Libra, Massimo

    2016-11-01

    It is well known that the occupational exposure to contaminants and carcinogens leads to the development of cancer in exposed workers. In the 18th century, Percivall Pott was the first to hypothesize that chronic exposure to dust in the London chimney sweeps was associated with an increased risk of developing cancer. Subsequently a growing body of evidence indicated that other physical factors were also responsible for oncogenic mutations. Over the past decades, many carcinogens have been found in the occupational environment and their presence is often associated with an increased incidence of cancer. Occupational exposure involves several factors and the association between carcinogens, occupational exposure and cancer is still unclear. Only a fraction of factors is recognized as occupational carcinogens and for each factor, there is an increased risk of cancer development associated with a specific work activity. According to the International Agency for Research on Cancer (IARC), the majority of carcinogens are classified as 'probable' and 'possible' human carcinogens, while, direct evidence of carcinogenicity is provided in epidemiological and experimental studies. In the present review, exposures to benzene, pesticides and mineral fibers are discussed as the most important cancer risk factors during work activities.

  9. Occupational exposure to carcinogens: Benzene, pesticides and fibers

    Science.gov (United States)

    Falzone, Luca; Marconi, Andrea; Loreto, Carla; Franco, Sabrina; Spandidos, Demetrios A.; Libra, Massimo

    2016-01-01

    It is well known that the occupational exposure to contaminants and carcinogens leads to the development of cancer in exposed workers. In the 18th century, Percivall Pott was the first to hypothesize that chronic exposure to dust in the London chimney sweeps was associated with an increased risk of developing cancer. Subsequently a growing body of evidence indicated that other physical factors were also responsible for oncogenic mutations. Over the past decades, many carcinogens have been found in the occupational environment and their presence is often associated with an increased incidence of cancer. Occupational exposure involves several factors and the association between carcinogens, occupational exposure and cancer is still unclear. Only a fraction of factors is recognized as occupational carcinogens and for each factor, there is an increased risk of cancer development associated with a specific work activity. According to the International Agency for Research on Cancer (IARC), the majority of carcinogens are classified as ‘probable’ and ‘possible’ human carcinogens, while, direct evidence of carcinogenicity is provided in epidemiological and experimental studies. In the present review, exposures to benzene, pesticides and mineral fibers are discussed as the most important cancer risk factors during work activities. PMID:27748850

  10. Determination and correlation of (liquid + liquid) equilibria of ternary and quaternary systems with octane, decane, benzene and [BMpyr][DCA] at T = 298.15 K and atmospheric pressure

    International Nuclear Information System (INIS)

    Requejo, Patricia F.; Calvar, Noelia; Domínguez, Ángeles; Gómez, Elena

    2016-01-01

    Highlights: • The ionic liquid BMpyrDCA was studied as solvents to extract aromatics from alkanes. • (Liquid + liquid) equilibrium data were measured at T = 298.15 K for quaternary system and ternary systems. • Selectivity and solute distribution ratio were calculated and compared. • The comparison of results obtained on LLE data of ternary and quaternary systems was analyzed. • Experimental data were satisfactorily correlated using NRTL model. - Abstract: The suitability of the ionic liquid 1-butyl-1-methylpyrrolidinium dicyanamide, [BMpyr][DCA], as extraction solvent of benzene from its mixtures with octane and decane has been analyzed. (Liquid + liquid) equilibrium (LLE) data for the quaternary system {octane (1) + decane (2) + benzene (3) + [BMpyr][DCA] (4)} and for the ternary systems {octane (1) + benzene (2) + [BMpyr][DCA] (3)} and {decane (1) + benzene (2) + [BMpyr][DCA] (3)} were determined at T = 298.15 K and atmospheric pressure. Solute distribution ratios and selectivities were calculated from the experimental LLE data in order to evaluate the capability of [BMpyr][DCA] as extraction solvent. Finally, experimental results for the ternary and quaternary systems were correlated using the Non-Random Two-Liquid (NRTL) thermodynamic model.

  11. Environmental and biological monitoring of benzene during self-service automobile refueling.

    Science.gov (United States)

    Egeghy, P P; Tornero-Velez, R; Rappaport, S M

    2000-12-01

    Although automobile refueling represents the major source of benzene exposure among the nonsmoking public, few data are available regarding such exposures and the associated uptake of benzene. We repeatedly measured benzene exposure and uptake (via benzene in exhaled breath) among 39 self-service customers using self-administered monitoring, a technique rarely used to obtain measurements from the general public (130 sets of measurements were obtained). Benzene exposures averaged 2.9 mg/m(3) (SD = 5.8 mg/m(3); median duration = 3 min) with a range of values falling within a 274-fold range, and was comprised entirely of the within-person component of variance (representing exposures of the same subject at different times of refueling). The corresponding range for benzene concentrations in breath was 41-fold and was comprised primarily of the within-person variance component (74% of the total variance). Our results indicate that environmental rather than interindividual differences are primarily responsible for benzene exposure and uptake during automobile refueling. The study also demonstrates that self-administered monitoring can be efficiently used to measure environmental exposures and biomarkers among the general public.

  12. Anaerobic benzene degradation by Gram-positive sulfate-reducing bacteria.

    Science.gov (United States)

    Abu Laban, Nidal; Selesi, Drazenka; Jobelius, Carsten; Meckenstock, Rainer U

    2009-06-01

    Despite its high chemical stability, benzene is known to be biodegradable with various electron acceptors under anaerobic conditions. However, our understanding of the initial activation reaction and the responsible prokaryotes is limited. In the present study, we enriched a bacterial culture that oxidizes benzene to carbon dioxide under sulfate-reducing conditions. Community analysis using terminal restriction fragment length polymorphism, 16S rRNA gene sequencing and FISH revealed 95% dominance of one phylotype that is affiliated to the Gram-positive bacterial genus Pelotomaculum showing that sulfate-reducing Gram-positive bacteria are involved in anaerobic benzene degradation. In order to get indications of the initial activation mechanism, we tested the substrate utilization, performed cometabolism tests and screened for putative metabolites. Phenol, toluene, and benzoate could not be utilized as alternative carbon sources by the benzene-degrading culture. Cometabolic degradation experiments resulted in retarded rates of benzene degradation in the presence of phenol whereas toluene had no effect on benzene metabolism. Phenol, 2-hydroxybenzoate, 4-hydroxybenzoate, and benzoate were identified as putative metabolites in the enrichment culture. However, hydroxylated aromatics were shown to be formed abiotically. Thus, the finding of benzoate as an intermediate compound supports a direct carboxylation of benzene as the initial activation mechanism but additional reactions leading to its formation cannot be excluded definitely.

  13. The immunotoxicological pattern of subchronic and chronic benzene exposure in rats.

    Science.gov (United States)

    Karaulov, Alexander V; Mikhaylova, Irina V; Smolyagin, Alexander I; Boev, Viktor M; Kalogeraki, Alexandra; Tsatsakis, Aristides M; Engin, Ayse Basak

    2017-06-05

    Exposure to benzene and its inevitable metabolites can result in deleterious effects on human health, including lymphocytopenia, hematotoxicity and cancer. However, the duration of exposure might alter the effects including immune consequences. The aim of this study was to determine whether benzene could modulate lymphocyte proliferation induced by the T cell mitogen concanavalin A, in rats, at different exposure durations. 386 Wistar rats were assigned into control and treatment groups which were subdivided into groups for 45, 90 and 135days for 0,6mL/kg of drinking water mixed benzene treatment. The percentage of CD3+, CD4+, CD8+ spleen lymphocytes was defined using the flow cytometer. Interleukin (IL)-4, IL-6, IL-10 and interferon-gamma, in supernatants of splenocyte cultures stimulated with Concanavalin A, were assessed by enzyme-linked immunosorbent assay (ELISA) technique. The decrease in the total lymphocyte and T cell counts were associated with increased benzene exposure duration. Th2-type cytokine, IL-4 significantly increased, whereas IL-6, CD4+T cells, CD4+/CD8+ ratio and CD3+ T cells decreased. Despite the positive correlation between benzene toxicity and indicated increased immune responses, 45-day exposure to benzene appeared to be the most sensitive time point for evaluating benzene cytotoxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Thymic Atrophy: Experimental Studies and Therapeutic Interventions.

    Science.gov (United States)

    Majumdar, S; Nandi, D

    2018-01-01

    The thymus is essential for T cell development and maturation. It is extremely sensitive to atrophy, wherein loss in cellularity of the thymus and/or disruption of the thymic architecture occur. This may lead to lower naïve T cell output and limited TCR diversity. Thymic atrophy is often associated with ageing. What is less appreciated is that proper functioning of the thymus is critical for reduction in morbidity and mortality associated with various clinical conditions including infections and transplantation. Therefore, therapeutic interventions which possess thymopoietic potential and lower thymic atrophy are required. These treatments enhance thymic output, which is a vital factor in generating favourable outcomes in clinical conditions. In this review, experimental studies on thymic atrophy in rodents and clinical cases where the thymus atrophies are discussed. In addition, mechanisms leading to thymic atrophy during ageing as well as during various stress conditions are reviewed. Therapies such as zinc supplementation, IL7 administration, leptin treatment, keratinocyte growth factor administration and sex steroid ablation during thymic atrophy involving experiments in animals and various clinical scenarios are reviewed. Interventions that have been used across different scenarios to reduce the extent of thymic atrophy and enhance its output are discussed. This review aims to speculate on the roles of combination therapies, which by acting additively or synergistically may further alleviate thymic atrophy and boost its function, thereby strengthening cellular T cell responses. © 2017 The Foundation for the Scandinavian Journal of Immunology.

  15. Experimental study of trimethyl aluminum decomposition

    Science.gov (United States)

    Zhang, Zhi; Pan, Yang; Yang, Jiuzhong; Jiang, Zhiming; Fang, Haisheng

    2017-09-01

    Trimethyl aluminum (TMA) is an important precursor used for metal-organic chemical vapor deposition (MOCVD) of most Al-containing structures, in particular of nitride structures. The reaction mechanism of TMA with ammonia is neither clear nor certain due to its complexity. Pyrolysis of trimethyl metal is the start of series of reactions, thus significantly affecting the growth. Experimental study of TMA pyrolysis, however, has not yet been conducted in detail. In this paper, a reflectron time-of-flight mass spectrometer is adopted to measure the TMA decomposition from room temperature to 800 °C in a special pyrolysis furnace, activated by soft X-ray from the synchrotron radiation. The results show that generation of methyl, ethane and monomethyl aluminum (MMA) indicates the start of the pyrolysis process. In the low temperature range from 25 °C to 700 °C, the main product is dimethyl aluminum (DMA) from decomposition of TMA. For temperatures larger than 700 °C, the main products are MMA, DMA, methyl and ethane.

  16. Experimental study of finite Larmor radius effects

    International Nuclear Information System (INIS)

    Struve, K.W.

    1980-08-01

    Linear Z-pinches in Ar, Kr, Xe, N 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 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 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

  17. Experimental studies of fiber concrete creep

    Directory of Open Access Journals (Sweden)

    Korneeva Irina

    2017-01-01

    Full Text Available The results of two-stage experimental studies of the strength and deformation characteristics of fibrous concrete reinforced with steel fiber. In the experiments we used steel fiber with bent ends, which practically does not form "hedgehogs", which allows to achieve an even distribution of the fiber by volume. At the first stage, the cube and prismatic strength, deformability at central compression, a number of special characteristics are determined: water absorption, frost resistance, abrasion; the optimal percentage of fiber reinforcement and the maximum size of the coarse aggregate fraction were selected. Fiber reinforcement led to an increase in the strength of concrete at compression by 1,35 times and an increase in the tensile strength at bending by 3,4 times. At the second stage, the creep of fibrous concrete and plain concrete of similar composition at different stress levels was researched. Creep curves are plotted. It is shown that the use of fiber reinforcement leads to a decrease in creep strain by 21 to 30 percent, depending on the stress level.

  18. An experimental study on pedestrian classification.

    Science.gov (United States)

    Munder, S; Gavrila, D M

    2006-11-01

    Detecting people in images is key for several important application domains in computer vision. This paper presents an in-depth experimental study on pedestrian classification; multiple feature-classifier combinations are examined with respect to their ROC performance and efficiency. We investigate global versus local and adaptive versus nonadaptive features, as exemplified by PCA coefficients, Haar wavelets, and local receptive fields (LRFs). In terms of classifiers, we consider the popular Support Vector Machines (SVMs), feed-forward neural networks, and k-nearest neighbor classifier. Experiments are performed on a large data set consisting of 4,000 pedestrian and more than 25,000 nonpedestrian (labeled) images captured in outdoor urban environments. Statistically meaningful results are obtained by analyzing performance variances caused by varying training and test sets. Furthermore, we investigate how classification performance and training sample size are correlated. Sample size is adjusted by increasing the number of manually labeled training data or by employing automatic bootstrapping or cascade techniques. Our experiments show that the novel combination of SVMs with LRF features performs best. A boosted cascade of Haar wavelets can, however, reach quite competitive results, at a fraction of computational cost. The data set used in this paper is made public, establishing a benchmark for this important problem.

  19. Evapotranspiration studies for protective barriers: Experimental plans

    International Nuclear Information System (INIS)

    Link, S.O.; Waugh, W.J.

    1989-11-01

    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

  20. Evapotranspiration studies for protective barriers: Experimental plans

    Energy Technology Data Exchange (ETDEWEB)

    Link, S.O.; Waugh, W.J.

    1989-11-01

    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.

  1. Experimental study of the pile EL3

    International Nuclear Information System (INIS)

    1958-01-01

    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) [fr

  2. 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.

  3. Three coordination compounds based on benzene tetracarboxylate ...

    Indian Academy of Sciences (India)

    YUNLONG WU

    Three coordination compounds based on benzene tetracarboxylate ligand: syntheses, structures, thermal behaviors and luminescence properties. YUNLONG WU, CHANGKUN XIA, JUN QIAN and JIMIN XIE. ∗. School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013,. People's Republic of ...

  4. Radiocarbon dating methods using benzene liquid scintillation

    International Nuclear Information System (INIS)

    Togashi, Shigeko; Matsumoto, Eiji

    1983-01-01

    The radiocarbon dating method using benzene liquid scintillation is reported in detail. The results of measurement of NBS oxalic acid agree with the recommended value, indicating that isotopic fractionation during benzene synthesis can be negligible. Ten samples which have been already measured by gas counter are dated by benzene liquid scintillation. There is no significant difference in age for the same sample between benzene liquid scintillation and gas counters. It is shown that quenching has to be corrected for the young sample. Memory effect in stainless steel reaction vessel can be removed by using an exchangeable inner vessel and by baking it in the air. Using this method, the oldest age that can be measured with 2.3 g carbon is 40,000 years B.P. (author)

  5. An experimental and modeling study of the low- and high-temperature oxidation of cyclohexane

    Science.gov (United States)

    Serinyel, Zeynep; Herbinet, Olivier; Frottier, Ophélie; Dirrenberger, Patricia; Warth, Valérie; Glaude, Pierre Alexandre; Battin-Leclerc, Frédérique

    2013-01-01

    The experimental study of the oxidation of cyclohexane has been performed in a jet-stirred reactor at temperatures ranging from 500 to 1100 K (low- and intermediate temperature zones including the negative temperature-coefficient area), at a residence time of 2 s and for dilute mixtures with equivalence ratios of 0.5, 1, and 2. Experiments were carried out at quasi-atmospheric pressure (1.07 bar). The fuel and reaction product mole fractions were measured using online gas chromatography. A total of 34 reaction products have been detected and quantified in this study. Typical reaction products formed in the low-temperature oxidation of cyclohexane include cyclic ethers (1,2-epoxycyclohexane and 1,4-epoxycyclohexane), 5-hexenal (formed from the rapid decomposition of 1,3-epoxycyclohexane), cyclohexanone, and cyclohexene, as well as benzene and phenol. Cyclohexane displays high low-temperature reactivity with well-marked negative temperature-coefficient (NTC) behavior at equivalence ratios 0.5 and 1. The fuel-rich system (ϕ = 2) is much less reactive in the same region and exhibits no NTC. To the best of our knowledge, this is the first jet-stirred reactor study to report NTC in cyclohexane oxidation. Laminar burning velocities were also measured by the heated burner method at initial gas temperatures of 298, 358, and 398 K and at 1 atm. The laminar burning velocity values peak at ϕ = 1.1 and are measured as 40 and 63.1 cm/s for Ti = 298 and 398 K, respectively. An updated detailed chemical kinetic model including low-temperature pathways was used to simulate the present (jet-stirred reactor and laminar burning velocity) and literature experimental (laminar burning velocity, rapid compression machine, and shock tube ignition delay times) data. Reasonable agreement is observed with most of the products observed in our reactor, as well as the literature experimental data considered in this paper. PMID:24124264

  6. An analysis of violations of Osha's (1987) occupational exposure to benzene standard.

    Science.gov (United States)

    Williams, Pamela R D

    2014-01-01

    The Occupational Safety and Health Administration (OSHA), which was formed by the Occupational Safety and Health Act of 1970 (OSH Act), establishes enforceable health and safety standards in the workplace and issues violations and penalties for non-compliance with these standards. The purpose of the current study was to evaluate the number and type of violations of the OSHA (1987) Occupational Exposure to Benzene Standard. Violations of the OSHA Hazard Communication Standard (HCS), particularly those that may pertain to specific provisions of the benzene standard, were also assessed. All analyses were based on OSHA inspection data that have been collected since the early 1970s and that are publicly available from the U.S. Department of Labor enforcement website. Analysis of these data shows that fewer than a thousand OSHA violations of the benzene standard have been issued over the last 25+ years. The results for benzene are in contrast to those for some other toxic and hazardous substances that are regulated by OSHA, such as blood-borne pathogens, lead, and asbestos, for which there have been issued tens of thousands of OSHA violations. The number of benzene standard violations also varies by time period, standard provision, industry sector, and other factors. In particular, the greatest number of benzene standard violations occurred during the late 1980s to early/mid 1990s, soon after the 1987 final benzene rule was promulgated. The majority of benzene standard violations also pertain to noncompliance with specific provisions and subprovisions of the standard dealing with initial exposure monitoring requirements, the communication of hazards to employees, and medical surveillance programs. Only a small fraction of HCS violations are attributed, at least in part, to potential benzene hazards in the workplace. In addition, most benzene standard violations are associated with specific industries within the manufacturing sector where benzene or benzene

  7. Experimental studies of octahedral tilting in perovskites

    International Nuclear Information System (INIS)

    Howard, C.J.; Kennedy, B.J.; Chakoumakos, B.C.

    1999-01-01

    Full text: Structures of the perovskite family, ABX 3 , have interested crystallographers over many years, and continue to attract attention on account of their fascinating electrical and magnetic properties, and their significance in the earth sciences. The ideal perovskite (cubic) is a particularly simple structure, but also a demanding one, since aside from the lattice parameter there are no variable parameters in the structure. Consequently, the majority of perovskite structures show departures from the ideal, the most common distortion being the comer-linked tilting of the practically rigid BX 6 octahedral units. Following a group theoretical study in 1997, a number of experimental investigations of octahedral tilting have been undertaken in 1998, and these are reported in this presentation. The studies are of the perovskites, SrZrO 3 , SrHfO 3 , CaTiO 3 , NaTaO 3 and LaGaO 3 . In each case, the crystal structures have been followed at high temperatures, with particular attention being paid to temperature regimes in which only the simplest octahedral tilt (only one tilt axis) pertains. Neutron powder diffraction patterns have been recorded on the medium/high resolution diffractometer installed at beam port HB4 at the High Flux Isotope Reactor, at the Oak Ridge National Laboratory. Crystal structures have been refined by the Rietveld method, and angles of tilt of the oxygen octahedra derived from the atomic position parameters. Each of the first four perovskites listed above transforms from tetragonal (with a single tilt axis) to cubic, and in each case, as far as can be determined from our measurements, the tilt angle in the tetragonal phase decreases continuously towards zero. There are interesting differences, however, in the functional form of this variation. The LaGaO 3 transforms at modest temperature to a rhombohedral phase, also characterised by a single tilt axis, but though the tilt angle decreases slowly with increasing temperature, the sample

  8. Acclimation of aerobic-activated sludge degrading benzene derivatives and co-metabolic degradation activities of trichloroethylene by benzene derivative-grown aerobic sludge.

    Science.gov (United States)

    Wang, Shizong; Yang, Qi; Bai, Zhiyong; Wang, Shidong; Wang, Yeyao; Nowak, Karolina M

    2015-01-01

    The acclimation of aerobic-activated sludge for degradation of benzene derivatives was investigated in batch experiments. Phenol, benzoic acid, toluene, aniline and chlorobenzene were concurrently added to five different bioreactors which contained the aerobic-activated sludge. After the acclimation process ended, the acclimated phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic-activated sludge were used to explore the co-metabolic degradation activities of trichloroethylene (TCE). Monod equation was employed to simulate the kinetics of co-metabolic degradation of TCE by benzene derivative-grown sludge. At the end of experiments, the mixed microbial communities grown under different conditions were identified. The results showed that the acclimation periods of microorganisms for different benzene derivatives varied. The maximum degradation rates of TCE for phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic sludge were 0.020, 0.017, 0.016, 0.0089 and 0.0047 mg g SS(-1) h(-1), respectively. The kinetic of TCE degradation in the absence of benzene derivative followed Monod equation well. Also, eight phyla were observed in the acclimated benzene derivative-grown aerobic sludge. Each of benzene derivative-grown aerobic sludge had different microbial community composition. This study can hopefully add new knowledge to the area of TCE co-metabolic by mixed microbial communities, and further the understanding on the function and applicability of aerobic-activated sludge.

  9. 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

  10. Leukemia mortality by cell type in petroleum workers with potential exposure to benzene.

    OpenAIRE

    Raabe, G K; Wong, O

    1996-01-01

    Workers in the petroleum industry are potentially exposed to a variety of petrochemicals, including benzene or benzene-containing liquids. Although a large number of studies of petroleum workers have been conducted to examine leukemia and other cancer risks, few existing studies have investigated cell-type-specific leukemias. One of the major reasons for the lack of cell-type-specific analysis was the small number of deaths by cell type in individual studies. In the present investigation, all...

  11. Benzene and naphthalene in air and breath as indicators of exposure to jet fuel

    OpenAIRE

    Egeghy, P; Hauf-Cabalo, L; Gibson, R; Rappaport, S

    2003-01-01

    Aims: To estimate exposures to benzene and naphthalene among military personnel working with jet fuel (JP-8) and to determine whether naphthalene might serve as a surrogate for JP-8 in studies of health effects.

  12. Experimental study of UFT with concomitant radiotherapy

    International Nuclear Information System (INIS)

    Tanaka, Juichi; Inuyama, Yukio; Fujii, Masato; Takaoka, Tetsuro; Hosoda, Hyonosuke; Kawaura, Mitsuhiro

    1987-01-01

    It has been reported that the combination therapy of 5-FU and radiation is more effective than radiation therapy alone in the treatment of head and neck cancer. This fact probably results from the increased sensitivity of cancer cells to radiation when given in conjunction with administration of 5-FU. UFT is an anticancer agent which is mixture of futraful and uracil in a molar ratio of 1 : 4. UFT showed a higher response rate than 5-FU alone in the treatment of head and neck cancer. 5-FU concentration increases markedly in cancer tissue but remains at a low level in blood. Therefore, the combination of UFT and radiation is expected to show a higher response rate than the combination of 5-FU and radiation, because the efficacy of radiation against cancer tissue is thought to be further enhanced in tissues which contain high concentrations of 5-FU. In order to test the effectiveness of the combination of UFT and radiation, an experimental study was designed by using C57BL mice and YM12 fibrosarcoma. 5-FU and UFT were administered orally for twelve consecutive days and radiation was given for five consecutive days concomitantly. Results obtained are as follows: 1) the combination therapy of 5-FU and radiation was more effective than radiation therapy alone on YM12 fibrosarcoma but it did not reach statistical significance, 2) there was a statistically significant increase in efficacy of the combination therapy of UFT and radiation as opposed to radiation therapy alone or 5-FU plus radiation therapy, 3) no toxic effects were seen in the mice, and 4) the concentration of 5-FU in the tumor tissue was extremely higher in the UFT group than in 5-FU group. This result may explain the higher response to the tumor in the combination of UFT and radiation than in the 5-FU and radiation treatment. (author)

  13. Experimental microangiographic study in normal rabbit liver

    International Nuclear Information System (INIS)

    Kim, Yoon Gyoo; Park, Jong Yeon; Han, Kook Sang; Moon, Ki Ho; Choi, Chang Ho; Han, Koon Taek; Lee, Suck Hong; Kim, Byung Soo

    1994-01-01

    Microangiography is an experimental radiologic technique for evaluation of the morphology and the function of small vessels. The purpose of this study is to introduce a good microangiographic technique and to present the microangiographic appearance of normal hepatic vascular pattern. Five white rabbits weighing 2.5-2.9Kg were objected. Polyethylene catheters were inserted in portal vein and then in IVC. Heparin mixed normal saline (2cc/1000cc) was infused through portal vein and blood was drained to IVC. Barium suspension was infused via the catheter placed in portal vein until the liver surface showed satisfactory finding in barium filling. The liver was removed and this preparation was fixed in 10% formaline for 7 days. After fixation, the liver was sectioned on 1-2mm thickness. The slices were radiographed on high resolution plate using Faxitron. H-E staining of liver tissue was also done. The microbrium was well distributed in all small vessels without filling defect. And we could find the hexagonal shaped classic liver lobule, in which the central vein was located at central portion and portal vein at periphery. The enlargement was showed numerous sinusoids, but there was less dye in the central portion of lobule, but the central vein was well filled by microbarium. The peripheral portion of lobule was well filled with microbarium. So, we could find diamond shaped liver acinus, in which central vein was located at priperal portion and the center of liver acinus was terminal portal vein that growed out from a small portal space. The three acini made the complex acinus and acinar agglomerate was composed of three or four complex acini. It is considered that the liver acinus pattern of Rapparport is more acceptable on microangiography than the classic concept of hepatic lobule

  14. Water-clay interactions. Experimental study

    International Nuclear Information System (INIS)

    Gaucher, Eric

    1998-01-01

    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) [fr

  15. Solar pond conception - experimental and theoretical studies

    Energy Technology Data Exchange (ETDEWEB)

    Kurt, Huseyin [Zonguldak Karaelmas Univ., Technical Education Faculty, Karabuk (Turkey); Halici, Fethi [Sakarya Univ., Mechanical Engineering Dept., Adapazari (Turkey); Binark, A. Korhan [Marmara Univ., Technical Education Faculty, Istanbul (Turkey)

    2000-07-01

    A one dimensional transient mathematical model for predicting the thermal performance of the salt gradient solar pond is developed and presented. In this paper, the natural solar ponds and different artificial solar pond systems found in the literature are introduced. Necessary modifications are made on the experimental stand located in Istanbul Technical University, the experimental stand is introduced and natural phenomena produced in the pond by the different solar pond variations under natural conditions are observed. In the theoretical work based on a one dimensional unsteady state heat conduction model with internal heat generation, the energy and mass balance equations for the upper convective zone, the non-convective zone and the lower convective zone, all of which form the solar pond, are written in terms of differential equations. These equations are solved analytically and numerically. The results obtained from the analysis are compared with the experimental results. The temperature and the concentration profiles are separately presented in the figures. (Author)

  16. Experimental and Numerical Study of Damaged Cantilever

    DEFF Research Database (Denmark)

    Rytter, A.; Krawczuk, M.; Kirkegaard, Poul Henning

    2000-01-01

    of the results from experimental and numerical tests with hollow section cantileves containing fatigue cracks. Two different finite-element (FE) models have been used to estimate the modal parameters numerically. The first FE model consists of beam elements. The second FE model consists of traditional...... rectangular shell elements and one rectangular shell element with a transverse, internal, open crack. The analytical results from the numerical models are compared with data obtained from experimental tests. The numerical models give good agreements with the experimental data. The beam model takes...... into account only the first mode of the crack evaluation. In the shell model all three modes of the crack growth are taken into account. Nevertheless, the results obtained for both models are satisfactory because the beam is subjected to bending. It can be concluded that it is sufficient to use crack models...

  17. Development of a Control Strategy for Benzene Impurity in HPMCAS-Stabilized Spray-Dried Dispersion Drug Products Using a Science-Based and Risk-Based Approach.

    Science.gov (United States)

    Yue, Hongfei; Nicholson, Sarah J; Young, Joel D; Hsieh, Daniel; Ketner, Rodney J; Hall, Robert G; Sackett, Jeremy; Banks, Elizabeth C; Castoro, John A; Randazzo, Michael E

    2015-08-01

    To develop a strategy to control benzene, an ICH Q3C Class 1 impurity that may be present in spray solvents at ppm concentration, in amorphous polymer-stabilized spray-dried dispersion (SDD) products. Risk assessments included determining the probability for benzene concentration in primary spray solvents, the physical properties of volatiles, and the potential enrichment of benzene from solution to solid. Mechanistic understanding of benzene removal was gained through a benzene-spiked fate and tolerance (F&T) study simulating worst-case spray-drying conditions and application of diffusion models for secondary drying. The mass ratio of spray solution to solid presented the highest risk of benzene enrichment. With slow spray-drying kinetics, benzene was reduced about 700-fold. Under standard secondary-drying conditions to remove residual solvents, residual benzene was further removed. Using diffusion models, the maximum benzene concentration was approximated for SDDs dried to the in-process control (IPC) limit of primary solvents. Two critical control points were established to eliminate any risk of residual benzene reaching patients: (1) upstream control of benzene in solvents (≤10 ppm) and (2) IPC of residual solvents in polymer-stabilized SDDs.

  18. 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.

  19. Environmental, Occupational Exposures to Benzene and Cancer: a Meta –analysis

    Directory of Open Access Journals (Sweden)

    Onny Setiani

    2015-12-01

    Full Text Available ABSTRACT Background: Many epidemiological studies have been able to address the relationships between benzene exposure in the environment  and  the level of risk. Incidence has risen in industrialized countries since the 1960s and is highly and rapidly fatal and represent the fifth leading cause of deaths from cancer  and 50%-100%  more  common in men than women. To identify, appraising and synthesizing  the risk of cancer from benzene exposure in environment or workplace,  a meta analysis is conducted. Method: Epidemiological studies were identified through a computerized Medline and search on follow up and case control studies.  The risk were identified as Standardized Mortality Ratios (SMRs, Standardized Incidence Ratios (SIRs, Relative Risk (RR and Odd Ratio (OR.   Data extraction covered characteristic of the study (publication year, country, study type, case definition, sources of cases, reference population, follow up period, risk measures and  risk estimates. The extracted data were checked for consistency and entered into a database and checked for correctness. Summary of  relative risk was calculated from log(RR and log(upper and lower limit of 95% CI of log RR. SE and weight of all studies were estimated by fixed effect model. Results: The identified studies  were industrial-based (n=6, community-based (n=2,  and multicentre hospital-based study (n=2. RR of each study were also show benzene exposure was favour to risk of malignancy. This findings indicated workers who were exposed to benzene have risk to get malignancy 2 times higher than  person who were not exposed to benzene. The excess risk found for Benzene was based on 8 population that were exposed with benzene from oil or petroleum  industry. The risk of soft tissue carcinoma due to benzene exposure was highest  with RR=15,59 (95% CI= 1.74-139.3.  The lowest risk was  stomach carcinoma RR 2,51  (95% CI= 1,60-2,94 and hemopoetic malignancy in general with RR

  20. Optimization of a novel method for determination of benzene, toluene, ethylbenzene, and xylenes in hair and waste water samples by carbon nanotubes reinforced sol-gel based hollow fiber solid phase microextraction and gas chromatography using factorial experimental design.

    Science.gov (United States)

    Es'haghi, Zarrin; Ebrahimi, Mahmoud; Hosseini, Mohammad-Saeid

    2011-05-27

    A novel design of solid phase microextraction fiber containing carbon nanotube reinforced sol-gel which was protected by polypropylene hollow fiber (HF-SPME) was developed for pre-concentration and determination of BTEX in environmental waste water and human hair samples. The method validation was included and satisfying results with high pre-concentration factors were obtained. In the present study orthogonal array experimental design (OAD) procedure with OA(16) (4(4)) matrix was applied to study the effect of four factors influencing the HF-SPME method efficiency: stirring speed, volume of adsorption organic solvent, extraction and desorption time of the sample solution, by which the effect of each factor was estimated using individual contributions as response functions in the screening process. Analysis of variance (ANOVA) was employed for estimating the main significant factors and their percentage contributions in extraction. Calibration curves were plotted using ten spiking levels of BTEX in the concentration ranges of 0.02-30,000ng/mL with correlation coefficients (r) 0.989-0.9991 for analytes. Under the optimized extraction conditions, the method showed good linearity (0.3-20,000ng/L), repeatability, low limits of detections (0.49-0.7ng/L) and excellent pre-concentration factors (185-1872). The best conditions which were estimated then applied for the analysis of BTEX compounds in the real samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Experimental Study of a Thermoelectric Generation System

    DEFF Research Database (Denmark)

    Zhu, Junpeng; Gao, Junling; Chen, Min

    2011-01-01

    . 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....

  2. Experimental methods to study tokamak plasma stability

    International Nuclear Information System (INIS)

    Perez-Navarro, A.

    1978-01-01

    Experimental devices to measure external instability modes with small pick-up coils to detect poloidal magnetic field fluctuations, and internal modes with soft-X-ray detectors are discussed. The characteristics of these devices are calculated for a small tokamak (R 0 = 30 cm, a = 10 cm, I 0 50 KA). (author)

  3. 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

  4. Experimental study of chemotherapy related leukocytopenia treated ...

    African Journals Online (AJOL)

    ... the positive control drug is G-CSF, respectively fill five kinds of peroal Leucocyte increasing drugs (Qijiao Shengbai Capsule, Weixuening Granule, Compound Zaofan Pill, Berbamine and Leucogen Tablets) in the stomach, the experimental group was divided into normal control group (group A), model group (group B), ...

  5. Economic principles in communication: An experimental study

    NARCIS (Netherlands)

    De Jaegher, K.; Rosenkranz, S.; Weitzel, G.U.

    2014-01-01

    This paper experimentally investigates how economic principles affect communication. In a simple sender–receiver game with common interests over payoffs, the sender can send a signal without a pre-given meaning in an infrequent or frequent state of the world. When the signal is costly, several

  6. 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...

  7. Simulating Retention in Gas-Liquid Chromatography: Benzene, Toluene, and Xylene Solutes

    Energy Technology Data Exchange (ETDEWEB)

    WICK,COLLIN D.; MARTIN,MARCUS G.; SIEPMANN, J. ILJA; SCHURE,MARK R.

    2000-07-12

    Accurate predictions of retention times, retention indices, and partition constants are a long sought-after goal for theoretical studies in chromatography. Although advances in computational chemistry have improved the understanding of molecular interactions, little attention has been focused on chromatography, let alone calculations of retention properties. Configurational-bias Monte Carlo simulations in the isobaric-isothermal Gibbs ensemble were used to investigate the partitioning of benzene, toluene, and the three xylene isomers between a squalane liquid phase and a helium vapor phase. The united-atom representation of the TraPPE (Transferable Potentials for Phase Equilibria) force field was used for all solutes and squalane. The Gibbs free energies of transfer and Kovats retention indices of the solutes were calculated directly from the partition constants (which were averaged over several independent simulations). While the calculated Kovats indices of benzene and toluene at T = 403 K are significantly higher than their experimental counterparts, much better agreement is found for the xylene isomers at T = 365 K.

  8. Subpicosecond pulse radiolysis in liquid methyl-substituted benzene derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Kazumasa [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)]. E-mail: kazu62@sanken.osaka-u.ac.jp; Kozawa, Takahiro [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Saeki, Akinori [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Yoshida, Yoichi [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Tagawa, Seiichi [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)]. E-mail: tagawa@sanken.osaka-u.ac.jp

    2007-05-15

    The early processes of radiation chemistry in the picosecond time region in methyl-substituted benzene derivatives have been investigated using subpicosecond pulse radiolysis. In o-xylene, a fairly slow geminate ion recombination was observed within 50 ps after the electron beam irradiation; this is due to the smaller electron mobility. The kinetic traces were analyzed using the Smoluchowski equation with exponential and modified-Gaussian (YGP) functions as the distribution of thermalized electrons. Only exponential functions well reproduced the experimental data within 50 ps after the electron pulse.

  9. The (p, ρ, T) of (methanol + benzene) and (methanol + ethylbenzene)

    International Nuclear Information System (INIS)

    Naziev, Yashar M.; Shahverdiyev, Astan N.; Hasanov, Vaqif H.

    2005-01-01

    The (p, ρ, T) of methanol, ethylbenzene and (methanol + benzene) and (methanol + ethylbenzene) at temperatures between (290 and 500) K and pressures in the range (0.1 to 60) MPa have been measured with a magnetic suspension densimeter with an uncertainty of ±0.1%. Our measurements with methanol deviate from the literature values by less than 0.2%. The (p, ρ, T) measurements were fitted with experimental uncertainties by an empirical equation. The temperature and mole fraction dependence of the coefficients of the equation of state are presented

  10. Subpicosecond pulse radiolysis in liquid methyl-substituted benzene derivatives

    International Nuclear Information System (INIS)

    Okamoto, Kazumasa; Kozawa, Takahiro; Saeki, Akinori; Yoshida, Yoichi; Tagawa, Seiichi

    2007-01-01

    The early processes of radiation chemistry in the picosecond time region in methyl-substituted benzene derivatives have been investigated using subpicosecond pulse radiolysis. In o-xylene, a fairly slow geminate ion recombination was observed within 50 ps after the electron beam irradiation; this is due to the smaller electron mobility. The kinetic traces were analyzed using the Smoluchowski equation with exponential and modified-Gaussian (YGP) functions as the distribution of thermalized electrons. Only exponential functions well reproduced the experimental data within 50 ps after the electron pulse

  11. Method to deterministically study photonic nanostructures in different experimental instruments

    NARCIS (Netherlands)

    Husken, B.H.; Woldering, L.A.; Blum, Christian; Tjerkstra, R.W.; Vos, Willem L.

    2009-01-01

    We describe an experimental method to recover a single, deterministically fabricated nanostructure in various experimental instruments without the use of artificially fabricated markers, with the aim to study photonic structures. Therefore, a detailed map of the spatial surroundings of the

  12. 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

  13. Model refinement for offshore platforms: Experimental study

    Science.gov (United States)

    Zhang, Min; Chen, Zongli; Wu, Yanjian

    2017-08-01

    Offshore jacket platforms are widely used in offshore oil and gas exploitation. Finite element models of such structures need to have many degrees of freedom (DOFs) to represent the geometrical detail of complex structures, thereby leading to incompatibility in the number of DOFs of experimental models. To bring them both to the same order while ensuring that the essential eigen- properties of the refined model match those of experimental models, an extended model refinement procedure is presented in this paper. Vibration testing of an offshore jacket platform model is performed to validate the applicability of the proposed approach. A full-order finite element model of the platform is established and then tuned to meet the measured modal properties identified from the acceleration signals. Both model reduction and modal expansion methods are investigated, as well as various scenarios of sensor arrangements. Upon completion of the refinement, the updated jacket platform model matches the natural frequencies of the measured model well.

  14. Radiolysis of Aqueous Benzene Solutions

    International Nuclear Information System (INIS)

    Christensen, H.

    1964-05-01

    Aerated and deaerated aqueous solutions of benzene have been irradiated with 60 Co 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(H 2 ) = 0.44 (0. 43) and G(H 2 O 2 ) = 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 + H 2 O 2 ) >> k(H + H 2 O 2 ). Furthermore, the results indicate that a competition takes place between the reactions: 2 C 6 H 6 OH · -> dimer -> biphenyl. C 6 H 7 · + C 6 H 6 OH · -> dimer -> biphenyl. The yields in aerated, unbuffered or acid, solutions were: G(phenol) = 2.1 (2.3), G(biphenyl) = 0 (0), and G(H 2 O 2 ) = 2.2 (3.1), the figures in brackets being valid for acid solutions. The ratio k(H + C 6 H 6 )/k(H + O 2 ) was 1.4x10 -2 . The results indicate that peroxides, or more probably hydroperoxides, take part in the reactions. After the addition of Fe 2+ or Fe 3+ 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

  15. 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.

  16. Anaerobic Benzene Oxidation via Phenol in Geobacter metallireducens

    Science.gov (United States)

    Tremblay, Pier-Luc; Chaurasia, Akhilesh Kumar; Smith, Jessica A.; Bain, Timothy S.; Lovley, Derek R.

    2013-01-01

    Anaerobic activation of benzene is expected to represent a novel biochemistry of environmental significance. Therefore, benzene metabolism was investigated in Geobacter metallireducens, the only genetically tractable organism known to anaerobically degrade benzene. Trace amounts (benzene to carbon dioxide with the reduction of Fe(III). Phenol was not detected in cell-free controls or in Fe(II)- and benzene-containing cultures of Geobacter sulfurreducens, a Geobacter species that cannot metabolize benzene. The phenol produced in G. metallireducens cultures was labeled with 18O during growth in H218O, as expected for anaerobic conversion of benzene to phenol. Analysis of whole-genome gene expression patterns indicated that genes for phenol metabolism were upregulated during growth on benzene but that genes for benzoate or toluene metabolism were not, further suggesting that phenol was an intermediate in benzene metabolism. Deletion of the genes for PpsA or PpcB, subunits of two enzymes specifically required for the metabolism of phenol, removed the capacity for benzene metabolism. These results demonstrate that benzene hydroxylation to phenol is an alternative to carboxylation for anaerobic benzene activation and suggest that this may be an important metabolic route for benzene removal in petroleum-contaminated groundwaters, in which Geobacter species are considered to play an important role in anaerobic benzene degradation. PMID:24096430

  17. Mechanisms of free radical chemistry and biochemistry of benzene

    International Nuclear Information System (INIS)

    Karam, L.R.; Simic, M.G.

    1989-01-01

    o-Tyrosine (o-Tyr) was used as a specific biomarker for OH radicals generated in biosystems. Specificity of o-Tyr as an OH biomarker was based on previous studied in systems exposed to ionizing radiations. Fresh muscle tissue incubated with benzene for 1 hr at 38 degree C exhibits formation of o-Tyr as seen in the cases of ethanol- and carbon tetrachloride-exposed systems. Gas chromatography/mass spectrometry selective ion monitoring measurements of o-Tyr yields in chicken breast muscle incubated with water or benzene indicate levels of less than 0.1 ppm and 3.0 ± 0.5 ppm of o-Tyr, respectively. Formation of OH is presumed to originate via a Haber-Weiss reaction of H 2 O 2 with Fe (II) preceded by the formation of O 2 and H 2 O 2 from distorted mitochondria

  18. Anaerobic Degradation of Benzene and Polycyclic Aromatic Hydrocarbons.

    Science.gov (United States)

    Meckenstock, Rainer U; Boll, Matthias; Mouttaki, Housna; Koelschbach, Janina S; Cunha Tarouco, Paola; Weyrauch, Philip; Dong, Xiyang; Himmelberg, Anne M

    2016-01-01

    Aromatic hydrocarbons such as benzene and polycyclic aromatic hydrocarbons (PAHs) are very slowly degraded without molecular oxygen. Here, we review the recent advances in the elucidation of the first known degradation pathways of these environmental hazards. Anaerobic degradation of benzene and PAHs has been successfully documented in the environment by metabolite analysis, compound-specific isotope analysis and microcosm studies. Subsequently, also enrichments and pure cultures were obtained that anaerobically degrade benzene, naphthalene or methylnaphthalene, and even phenanthrene, the largest PAH currently known to be degradable under anoxic conditions. Although such cultures grow very slowly, with doubling times of around 2 weeks, and produce only very little biomass in batch cultures, successful proteogenomic, transcriptomic and biochemical studies revealed novel degradation pathways with exciting biochemical reactions such as for example the carboxylation of naphthalene or the ATP-independent reduction of naphthoyl-coenzyme A. The elucidation of the first anaerobic degradation pathways of naphthalene and methylnaphthalene at the genetic and biochemical level now opens the door to studying the anaerobic metabolism and ecology of anaerobic PAH degraders. This will contribute to assessing the fate of one of the most important contaminant classes in anoxic sediments and aquifers. © 2016 S. Karger AG, Basel.

  19. Experimental studies of coaxial plasma gun current

    International Nuclear Information System (INIS)

    Price, D.W.

    1988-01-01

    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 10 5 to 10 6 m/s. Only the single particle drift and the slug model calculations are of the right magnitude (8 x 10 5 m/s). The Fishbine and the Rosenbluth models predict slower velocities (2 x 10 5 m/s). The Alfven model is not applicable to this system

  20. Experimental study of helicopter fuselage drag

    OpenAIRE

    Stepanov, Robert; Zherekov, Vladimir; Pakhov, Vladimir; Mikhailov, Sergey; Garipov, Aleksey; Yakubov, Walter; Barakos, George N.

    2016-01-01

    Experimental data are presented for the parasite drag of various helicopter fuselage components, such as skids, external fuel tanks, and tailplane. The experiments were conducted at the Kazan National Research Technical University (Kazan Aviation Institute) T-1K wind tunnel, investigating four versions of a fuselage similar to the Ansat helicopter. It was found that, for the range of pitch angles −10≤α≤10  deg−10≤α≤10  deg, the skids added 80% to the drag of the bare fuselage, whereas the tai...

  1. Experimental study of the nucleon spin structure

    International Nuclear Information System (INIS)

    Litmaath, M.F.

    1996-01-01

    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.)

  2. Experimental Studies of Coaxial Plasma Gun Current

    Science.gov (United States)

    1988-09-01

    insertion into experimental systems (117-133), fueling for proposed thermonuclear reactors (134-138], breeding fissionable material [139, 140] and...Center Top Level Linear Exponential Yield Current Current Extrap . Extrap . (MA) (MA) Current Current (MA) (MA) 02901 2.8106 0.18 0.05 D3001 1.2x107...Exponential Yield Current Current Extrap . Extrap . (MA) (MA) Current Current (MA) (MA) 30703 1.610 8 1.57 0.64 0.54 0.59 J0706 4.040O 1.46 0.85 0.80 0.82 J

  3. Investigation on minimum ignition energy of mixtures of α-pinene-benzene/air.

    Science.gov (United States)

    Coudour, B; Chetehouna, K; Rudz, S; Gillard, P; Garo, J P

    2015-01-01

    Minimum ignition energies (MIE) of α-pinene-benzene/air mixtures at a given temperature for different equivalence ratios and fuel proportions are experimented in this paper. We used a cylindrical chamber of combustion using a nanosecond pulse at 1,064 nm from a Q-switched Nd:YAG laser. Laser-induced spark ignitions were studied for two molar proportions of α-pinene/benzene mixtures, respectively 20-80% and 50-50%. The effect of the equivalence ratio (Φ) has been investigated for 0.7, 0.9, 1.1 and 1.5 and ignition of fuel/air mixtures has been experimented for two different incident laser energies: 25 and 33 mJ. This study aims at observing the influence of different α-pinene/benzene proportions on the flammability of the mixture to have further knowledge of the potential of biogenic volatile organic compounds (BVOCs) and smoke mixtures to influence forest fires, especially in the case of the accelerating forest fire phenomenon (AFF). Results of ignition probability and energy absorption are based on 400 laser shots for each studied fuel proportions. MIE results as functions of equivalence ratio compared to data of pure α-pinene and pure benzene demonstrate that the presence of benzene in α-pinene-air mixture tends to increase ignition probability and reduce MIE without depending strongly on the α-pinene/benzene proportion. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Multi-scale simulation on solid benzene

    Science.gov (United States)

    Liu, Hua; Heinz, Hendrik

    2009-03-01

    Solid Benzene is used in organic semiconductors for photovoltaics, which often include pi-conjugated systems. We use MD simulations method to explore the relationship between the structure and interaction energy of two kinds of solid benzene, with the Pbca and P21c crystallgraphic structures respectively. Simple relevant force fields (PCFF and CVFF) are examined with regard to their performance on the structure and energetics of benzene dimers and benzene crystals which serve as well characterized model systems. However, MD simulations cannot get the transport properties. So the combination of reliable classical atomistic simulations and quantum-mechanical methods is needed to understand the dynamics of charge transport and self-assembly processes involving pi-conjugated oligomers and polymers. As alternative and accurate models, we explore atomistic models with additional sites which represent the location of the pi electrons and are characterized by suitable charges and van-der-Waals parameters. With these parameters, it will be possible to reproduce the dimer geometries and energies, the crystal structure of solid benzene, as well as pi-stacking forces and free energies for similar systems.

  5. 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.

  6. 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.

  7. 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.

  8. Disturbance response indicators of Impatiens walleriana exposed to benzene and chromium.

    Science.gov (United States)

    Campos, V; Lessa, S S; Ramos, R L; Shinzato, M C; Medeiros, T A M

    2017-08-03

    The purpose of this study was to evaluate the remediation potential and disturbance response indicators of Impatiens walleriana exposed to benzene and chromium. Numerous studies over the years have found abundant evidence of the carcinogenicity of benzene and chromium (VI) in humans. Benzene and chromium are two toxic industrial chemicals commonly found together at contaminated sites, and one of the most common management strategies employed in the recovery of sites contaminated by petroleum products and trace metals is in situ remediation. Given that increasing interest has focused on the use of plants as depollution agents, direct injection tests and benzene misting were performed on I. walleriana to evaluate the remediation potential of this species. I. walleriana accumulated hexavalent chromium, mainly in the root system (164.23 mg kg -1 ), to the detriment of the aerial part (39.72 mg kg -1 ), and presented visible damage only at the highest concentration (30 mg L -1 ). Unlike chromium (VI), chromium (III) was retained almost entirely by the soil, leaving it available for removal by phytotechnology. However, after the contamination stopped, I. walleriana responded positively to the detoxification process, recovering its stem stiffness and leaf color. I. walleriana showed visible changes such as leaf chlorosis during the ten days of benzene contamination. When benzene is absorbed by the roots, it is translocated to and accumulated in the plant's aerial part. This mechanism the plant uses ensures its tolerance to the organic compound, enabling the species to survive and reproduce after treatment with benzene. Although I. walleriana accumulates minor amounts of hexavalent chromium in the aerial part, this amount suffices to induce greater oxidative stress and to increase the amount of hydrogen peroxide when compared to that of benzene. It was therefore concluded that I. walleriana is a species that possesses desirable characteristics for phytotechnology.

  9. 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.

  10. Combined experimental and theoretical studies on the photophysical properties of cycloparaphenylenes.

    Science.gov (United States)

    Segawa, Yasutomo; Fukazawa, Aiko; Matsuura, Sanae; Omachi, Haruka; Yamaguchi, Shigehiro; Irle, Stephan; Itami, Kenichiro

    2012-08-14

    We studied the UV-vis absorption and fluorescence in solution/solid states of [n]cycloparaphenylene ([n]CPP: n = 9, 12, 14, 15, and 16), and conducted theoretical studies to better understand the experimental results. The representative experimental findings include (i) the most intense absorption maxima (λ(abs1)) display remarkably close values (338-339 nm), (ii) the longest-wavelength absorption maxima (λ(abs2)) are blue-shifted with increasing the ring size (395 → 365 nm), (iii) the emission maxima (λ(em)) are blue-shifted with increasing the ring size (494 → 438 nm for longest-wavelength maxima), (iv) the fluorescent quantum yields (Φ(F)) in solution are high (0.73-0.90), (v) the fluorescence lifetimes (τ(s)) of [9]- and [12]CPP are 10.6 and 2.2 ns, respectively, and (vi) the Φ(F) values slightly increase in polymer matrix but significantly decrease in the crystalline state. According to TD-DFT calculations, the longest-wavelength absorption (λ(abs2)) corresponds to a forbidden HOMO → LUMO transition and the most intense absorption (λ(abs1)) corresponds to degenerate HOMO - 1 → LUMO and HOMO → LUMO + 1 transitions with high oscillator strength. The interesting and counterintuitive optical properties of CPPs (constant λ(abs1) and blue shift of λ(abs2)) could be ascribed mainly to the ring-size effect in frontier molecular orbitals (in particular the increase of the HOMO-LUMO gap as the number of benzene rings increases). On the basis of comparative calculations using hypothetical model geometries, we conclude that the unique behavior of HOMO and LUMO of CPPs is due mainly to their lack of a conjugation length dependence in combination with a significant bending effect (particularly to HOMO) and a torsion effect (particularly to LUMO).

  11. 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.

  12. Percutaneous penetration of benzene in hairless mice: an estimate of dermal absorption during tire-building operations.

    Science.gov (United States)

    Susten, A S; Dames, B L; Burg, J R; Niemeier, R W

    1985-01-01

    Repeated skin contact with solvents containing as much as 0.5% benzene is common in workers building regular bias passenger tires. To estimate the amount of benzene absorbed through the skin of these workers, a series of in vivo studies was conducted in hairless mice. Percutaneous absorption, following single dermal applications of 14C-benzene contained in rubber solvent at a concentration of 0.5% (v/v), was calculated directly from the sums of radioactivity found in excreta, expired breath, and the carcass. Data from the study, together with observations made during tire-building operations, suggest that a worker could absorb 4-8 mg of benzene daily through the skin. This compares to 14 mg per day via inhalation at the NIOSH recommended standard of 1 ppm. Thus dermal absorption could contribute from 20-40% of the total benzene dose of these workers.

  13. Understanding the properties of inorganic benzenes based on π-electron densities.

    Science.gov (United States)

    Wu, Wenjie; Li, Xiaoyan; Meng, Lingpeng; Zheng, Shijun; Zeng, Yanli

    2015-03-12

    The properties of inorganic benzenes have been investigated by means of second-order Møller-Plesset perturbation theory (MP2) calculations and quantum theory of atoms in molecules (QTAIM) studies. In this work, the σ- and π-electron densities were separated from the total electron densities, and it was therefore possible to evaluate the contributions of σ and π electrons to the chemical bonds and properties of inorganic benzenes. The following conclusions are given: (1) The π-attractors' positions correlate to their respective atomic radii. With increasing atomic number in the same period, the attractor of π-electron densities becomes closer to its respective nucleus. With increasing atomic number in the main group, the position of the π attractor becomes farther from its respective nucleus. (2) The strength of the chemical bonds of the inorganic benzene rings is determined by σ-electron densities, not π-electron densities; their bonding character is mainly determined by the σ-electron density; however, the role of the π-electron density cannot be neglected. (3) For the inorganic benzenes studied, the electron localization function for π (ELFπ) values are related to the differences of the electronegativity between the neighboring atoms of the inorganic benzene rings, Δχ(X,Y). The smaller the difference of Δχ(X,Y), the higher the value of ELFπ, resulting in more aromatic properties of the inorganic benzenes.

  14. 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.

  15. Theoretical and experimental studies of elementary physics

    International Nuclear Information System (INIS)

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

    1992-01-01

    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

  16. 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

  17. Experimental and modeling study on pyrolysis of n-decane initiated by nitromethane

    KAUST Repository

    Jia, Zhenjian

    2016-01-15

    Initiator could accelerate the rate of hydrocarbon pyrolysis and reduce the required material temperatures for a hypersonic aircraft heat exchanger/reactor. Nitroalkanes were proposed as the effective initiator because of the lower CN bond dissociation energy. In order to investigate the initiation mechanism of nitroalkanes on hydrocarbon pyrolysis, the pyrolysis of n-decane, nitromethane and their binary mixture were carried out at 30, 150 and 760 Torr in a flow reactor with synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). The identified and quantified pyrolysis species include C1C2 alkanes, C2C10 alkenes, C3C6 dialkenes, C2C3 alkynes, nitrogen oxides such as NO and NO2, benzene, and radicals including CH3, C3H3, and C3H5, which shed light on the mechanism of n-decane and nitromethane pyrolysis, as well as the interactions of these two fuels. The experimental results indicate that the addition of nitromethane decreases the initial decomposition temperature of n-decane, and a stronger promotion effect could be obtained as the experimental pressure increases. The distributions of alkanes, alkenes, dialkenes, alkynes and benzene are also influenced by the addition of nitromethane. A detailed kinetic model with 266 species and 1648 reactions was developed and validated against the mole fraction profiles of reactants, major products and important intermediates during the pyrolysis of each fuel and their binary mixture. The satisfactory model prediction to the experimental measurements permits the analysis of the kinetic effect of nitromethane initiation on the pyrolysis of n-decane. So that, the increase of the conversion rate at a lower temperature, the selectivity of decomposition products, and reduction of benzene formation are better understood.

  18. 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

  19. para-Benzene disulfonic acid and its tetrachloro and tetrafluoro derivatives--studies towards polyhalogenated metal-organic-frameworks with sulfo analogues of terephthalic acid.

    Science.gov (United States)

    Muesmann, Thomas W T; Zitzer, Christina; Mietrach, Andrea; Klüner, Thorsten; Christoffers, Jens; Wickleder, Mathias S

    2011-04-07

    We developed convenient synthetic routes for the preparation of para-benzene disulfonic acid (H(2)BDS) and its tetrachloro (H(2)BDSCl(4)) and tetrafluoro (H(2)BDSF(4)) derivatives. The reaction of these acids with zinc nitrate in DMF led to single crystals of [Zn(BDS)(DMF)(2)] (triclinic, P ̄1[combining macron], Z=2, a=976.62(4), b=986.85(4), c=1014.40(4), α=69.106(2)°, β=68.746(2)°, γ=86.295(2)°, wR(2)=0.0627), [Zn(BDSCl(4))(DMF)(4)] (triclinic, P ̄1[combining macron], Z=1, a=831.5(1), b=905.2(1), c=989.6(1), α=90.44(2)°, β=91.41 (2)°, γ=106.72(2)°, wR(2)=0.0635), and [Zn(BDSF(4))(DMF)(4)] (monoclinic, P2(1)/c, Z=2, a=889.01(3), b=968.91(3), c=1633.07(5) pm, β=106.524(2)°, wR(2)=0.0948). While [Zn(BDS)(DMF)(2)] exhibits a layer structure, the disulfonate linkers connect the zinc ions into chains in the crystal structures of [Zn(BDSCl(4))(DMF)(4)] and [Zn(BDSF(4))(DMF)(4)]. Thermoanalytical investigations revealed that desolvation of the compounds occurs in a temperature range between 100 and 200 °C. The solvent free sulfonates show remarkably high stabilities, [Zn(BDS)(DMF)(2)] is stable up to nearly 600 °C. The halogenated acids were also used to prepare copper salts from aqueous solutions and Cu(2)(OH)(2)(CO(3)) (malachite) as a copper source. The crystal structure of [Cu(H(2)O)(6)](BDSF(4)) (triclinic, P ̄1[combining macron], Z=1, a=510.45(2), b=744.68(3), c=1077.77(4) pm, α=85.627 (2)°, β=77.449 (2)°, γ=76.015 (2)°) exhibits complex cations and uncoordinated sulfonate anions, while in [Cu(BDSCl(4))(H(2)O)(4)] (orthorhombic, Pnma, Z=4, a=721.27(2), b=2147.81(6), c=979.42(3) pm) the Cu(2+) ions are linked to infinite chains in the crystal structure. The most interesting structural feature of [Cu(BDSCl(4))(H(2)O)(4)] is the significant deviation from planarity of the disulfonate dianion. Theoretical investigations revealed that a boat conformation is favoured due to steric hindrance in cases where a syn coordination of the sulfonate

  20. 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.

  1. 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

    Density functional theory has become a popular methodology for the analysis of molecular adsorption on surfaces. Despite this popularity, there exist adsorption systems for which commonly used exchange-correlation functionals fail miserably. Particularly those systems where binding is due to van...... 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....

  2. Early hematological and immunological alterations in gasoline station attendants exposed to benzene.

    Science.gov (United States)

    Moro, Angela M; Brucker, Natália; Charão, Mariele F; Sauer, Elisa; Freitas, Fernando; Durgante, Juliano; Bubols, Guilherme; Campanharo, Sarah; Linden, Rafael; Souza, Ana P; Bonorino, Cristina; Moresco, Rafael; Pilger, Diogo; Gioda, Adriana; Farsky, Sandra; Duschl, Albert; Garcia, Solange C

    2015-02-01

    Elucidation of effective biomarkers may provide tools for the early detection of biological alterations caused by benzene exposure and may contribute to the reduction of occupational diseases. This study aimed to assess early alterations on hematological and immunological systems of workers exposed to benzene. Sixty gasoline station attendants (GSA group) and 28 control subjects were evaluated. Environmental and biological monitoring of benzene exposure was performed in blood and urine. The potential effect biomarkers evaluated were δ-aminolevulinate dehydratase (ALA-D) activity, CD80 and CD86 expression in lymphocytes and monocytes, and serum interleukin-8 (IL-8). The influence of confounding factors and toluene co-exposure were considered. Although exposures were below ACGIH (American Conference of Governmental Industrial Hygienists) limits, reduced ALA-D activity, decreased CD80 and CD86 expression in monocytes and increased IL-8 levels were found in the GSA group compared to the control subjects. Furthermore, according to multiple linear regression analysis, benzene exposure was associated to a decrease in CD80 and CD86 expression in monocytes. These findings suggest, for the first time, a potential effect of benzene exposure on ALA-D activity, CD80 and CD86 expression, IL-8 levels, which could be suggested as potential markers for the early detection of benzene-induced alterations. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Molecular simulations and experimental studies of zeolites

    Science.gov (United States)

    Moloy, Eric C.

    Zeolites are microporous aluminosilicate tetrahedral framework materials that have symmetric cages and channels with open-diameters between 0.2 and 2.0 nm. Zeolites are used extensively in the petrochemical industries for both their microporosity and their catalytic properties. The role of water is paramount to the formation, structure, and stability of these materials. Zeolites frequently have extra-framework cations, and as a result, are important ion-exchange materials. Zeolites also play important roles as molecular sieves and catalysts. For all that is known about zeolites, much remains a mystery. How, for example, can the well established metastability of these structures be explained? What is the role of water with respect to the formation, stabilization, and dynamical properties? This dissertation addresses these questions mainly from a modeling perspective, but also with some experimental work as well. The first discussion addresses a special class of zeolites: pure-silica zeolites. Experimental enthalpy of formation data are combined with molecular modeling to address zeolitic metastability. Molecular modeling is used to calculate internal surface areas, and a linear relationship between formation enthalpy and internal surface areas is clearly established, producing an internal surface energy of approximately 93 mJ/m2. Nitrate bearing sodalite and cancrinite have formed under the caustic chemical conditions of some nuclear waste processing centers in the United States. These phases have fouled expensive process equipment, and are the primary constituents of the resilient heels in the bottom of storage tanks. Molecular modeling, including molecular mechanics, molecular dynamics, and density functional theory, is used to simulate these materials with respect to structure and dynamical properties. Some new, very interesting results are extracted from the simulation of anhydrous Na6[Si6Al 6O24] sodalite---most importantly, the identification of two distinct

  4. Azeotropic behaviour of (benzene + cyclohexane + chlorobenzene) ternary mixture using chlorobenzene as entrainer at 101.3 kPa

    Energy Technology Data Exchange (ETDEWEB)

    Silva, L.M.C. [Departamento de Engenharia Quimica, Escola Politecnica, Universidade Federal da Bahia, 40210 Salvador de Bahia (Brazil); Mattedi, S. [Departamento de Engenharia Quimica, Escola Politecnica, Universidade Federal da Bahia, 40210 Salvador de Bahia (Brazil); Gonzalez-Olmos, R. [Departament d' Enginyeria Quimica, Escola Tecnica Superior d' Enginyeria Quimica, Universitat Rovira i Virgili, Avinguda Paisos Catalans 26, Campus Sescelades, 43007 Tarragona (Spain); Iglesias, M. [Departament d' Enginyeria Quimica, Escola Tecnica Superior d' Enginyeria Quimica, Universitat Rovira i Virgili, Avinguda Paisos Catalans 26, Campus Sescelades, 43007 Tarragona (Spain)]. E-mail: miguelangel.iglesias@urv.net

    2006-12-15

    In this paper, the azeotropic behaviour of the (benzene + cyclohexane + chlorobenzene) ternary mixture was experimentally investigated with the aim of enhancing the knowledge for the feasible use of chlorobenzene as an entrainer for the azeotropic distillation of the binary azeotrope. Such a study has not been reported in the literature to the best of the authors' knowledge. (Vapour + liquid) equilibria data for (benzene + cyclohexane + chlorobenzene) at 101.3 kPa were obtained with a Othmer-type ebulliometer. Data were tested and considered thermodynamically consistent. The experimental results showed that this ternary mixture is completely miscible and exhibits an unique binary homogeneous azeotrope, an unstable node at the conditions studied, and the propitious topological characteristics (residual curve map and relative volatility) to be separated. Satisfactory results were obtained for the correlation of equilibrium compositions with the UNIQUAC activity coefficients model and also for prediction with the UNIFAC method. In both cases, low root mean square deviations of the vapour mole fraction and temperature were calculated. The capability of chlorobenzene as a modified distillation agent at atmospheric condition is discussed in terms of the thermodynamic topological analysis. A conceptual distillation scheme with reversed volatility is proposed to separate the azeotropic mixture. In order to reduce the operational cost requirements of the sequence of columns proposed, the range for optimal reflux and the ratio for feed flow conditions were studied.

  5. Experimental study of asymmetric heart valve prototype

    Science.gov (United States)

    Vukicevic, M.; Fortini, S.; Querzoli, G.; Cenedese, A.; Pedrizzetti, G.

    2011-11-01

    The mechanical heart valves (MHVs) are extremely important medical devices, commonly used for diseased heart valves replacement. Despite the long term of use and constant design refinement, the MHVs are very far from ideal and their performance is very diverse from that of the native ones. It has been approved that small variations in geometry of valvular leaflets influence the significant change in the intraventricular vortical flow, known as one of the most important factors for the overall functionality of the heart. We have experimentally examined the home-made heart valve prototypes, exclusively modeled for the mitral valve replacement. The performance and energetic properties of the prototypes have been compared with those in the presence of standard MHVs. The analysis was based on the testing of intraventricular fluid dynamics, usually missing criteria for the quality of the valve performance. It has been shown that the asymmetric prototype, with unequal leaflets and D-shaped orifice produces flow patterns and energetic properties close to those found in the healthy subjects. Thus, the break of symmetry in the standard bi-leaflet MHV prosthesis, at least from the fluid dynamics point of view, is worthwhile to be considered for the design of MHVs for the mitral valve replacement.

  6. Experimental studies on fast reactor upper shuttings

    International Nuclear Information System (INIS)

    Lemercier, G.; Sauvage, M.

    1980-04-01

    Super-Phenix -integrated pool type power reactor- requires large dimension upper shuttings, as compared to Phenix, and development of new solutions had to be undertaken, such as the use of metallic thermal insulations above the liquid sodium. A large number of tests have been fulfilled to adjust these solutions, and their validation for Super-Phenix has lead to the construction of a large mock up (diameter 6m), named 'Gulliver', representative of the upper shuttings, as far as geometrical similitude is concerned. These experiments, covering a lapse of 10700 hours concern essentially: - thermal insulations associated with cooled structures; - thermal problems concerning the crossings in the upper structure for large components, the cover gas, the link between the reactor vessel and the slab; - problems in relation with liquid sodium condensation on the structures. Presently, endurance tests on components are going on. This paper follows the one presented at the first conference, its object being the presentation of the experimental results obtained on Gulliver as well as a description of the envisaged future programs

  7. Inelastic X-ray scattering on liquid benzene analyzed using a generalized Langevin equation

    Science.gov (United States)

    Yoshida, Koji; Fukuyama, Nami; Yamaguchi, Toshio; Hosokawa, Shinya; Uchiyama, Hiroshi; Tsutsui, Satoshi; Baron, Alfred Q. R.

    2017-07-01

    The dynamic structure factor, S(Q,ω), of liquid benzene was measured by meV-resolved inelastic X-ray scattering (IXS) and analyzed using a generalized Langevin model with a memory function including fast, μ-relaxation and slow, structural, α-relaxation. The model well reproduced the experimental S(Q,ω) of liquid benzene. The dispersion relation of the collective excitation energy yields the high-frequency sound velocity for liquid benzene as related to the α-relaxation. The ratio of the high-frequency to the adiabatic sound velocity is approximately 1.5, larger to that of carbon tetrachloride and smaller than those of methanol and water, reflecting the nature of intermolecular interactions.

  8. Peer Review Comments on the IRIS Assessment of Benzene

    Science.gov (United States)

    Attachment to IRIS file for benzene, January 19, 2000, RESPONSE TO THE PEER REVIEW COMMENTS, II. Extrapolation of the Benzene Inhalation Unit Risk Estimate to the Oral Route of Exposure (EPA/NCEA-W-0517, July 1999)

  9. Economic principles in communication: an experimental study.

    Science.gov (United States)

    De Jaegher, Kris; Rosenkranz, Stephanie; Weitzel, Utz

    2014-12-21

    This paper experimentally investigates how economic principles affect communication. In a simple sender-receiver game with common interests over payoffs, the sender can send a signal without a pre-given meaning in an infrequent or frequent state of the world. When the signal is costly, several theories (focal point theory, the intuitive criterion, evolutionary game theory) predict an efficient separating equilibrium, where the signal is sent in the infrequent state of the world (also referred to as Horn׳s rule). To analyze whether Horn׳s rule applies, and if so, which theory best explains it, we develop and test variants of the sender-receiver game where the theories generate discriminatory hypotheses. In costly signaling variants, our participants follow Horn׳s rule most of the time, in a manner that is best explained by focal point theory. In costless signaling variants, evolutionary game theory best explains our results. Here participants coordinate significantly more (less) often on a separating equilibrium where the signal is sent in the frequent state if they are primed to associate the absence of a signal with the infrequent (frequent) state of the world. We also find indications that a similar priming effect applies to costly signals. Thus, while the frequency with which participants follow Horn׳s rule in costly signaling variants is best explained by Horn׳s rule, the priming effect shows that some of our participants׳ behavior is best explained by evolutionary game theory even when signals are costly. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Searching for DFT-based methods that include dispersion interactions to calculate the physisorption of H2 on benzene and graphene.

    Science.gov (United States)

    Cabria, I; López, M J; Alonso, J A

    2017-06-07

    Simulations of the hydrogen storage capacities of nanoporous carbons require an accurate treatment of the interaction of the hydrogen molecule with the graphite-like surfaces of the carbon pores, which is dominated by the dispersion forces. These interactions are described accurately by high level quantum chemistry methods, like the Coupled Cluster method with single and double excitations and a non-iterative correction for triple excitations (CCSD(T)), but those methods are computationally very expensive for large systems and for massive simulations. Density functional theory (DFT)-based methods that include dispersion interactions at different levels of complexity are less accurate, but computationally less expensive. In order to find DFT-methods that include dispersion interactions to calculate the physisorption of H 2 on benzene and graphene, with a reasonable compromise between accuracy and computational cost, CCSD(T), Møller-Plesset second-order perturbation theory method, and several DFT-methods have been used to calculate the interaction energy curves of H 2 on benzene and graphene. DFT calculations are compared with CCSD(T) calculations, in the case of H 2 on benzene, and with experimental data, in the case of H 2 on graphene. Among the DFT methods studied, the B97D, RVV10, and PBE+DCACP methods yield interaction energy curves of H 2 -benzene in remarkable agreement with the interaction energy curve obtained with the CCSD(T) method. With regards to graphene, the rev-vdW-DF2, PBE-XDM, PBE-D2, and RVV10 methods yield adsorption energies of the lowest level of H 2 on graphene, very close to the experimental data.

  11. Utilization of alternative fuels and materials in cement kiln towards emissions of benzene, toluene, ethyl-benzene and xylenes (BTEX

    Directory of Open Access Journals (Sweden)

    Muliane Ulfi

    2018-01-01

    Full Text Available Co-processing in cement industry has benefits for energy conservation and waste recycling. Nevertheless, emissions of benzene, toluene, ethyl-benzene, and xylenes (BTEX tend to increase compared to a non co-processing kiln. A study was conducted in kiln feeding solid AFR (similar to municipal solid waste, MSW having production capacity 4600-ton clinker/day (max. 5000 ton/day and kiln feeding biomass having production capacity 7800-ton clinker/day (max. 8000 ton/day. The concentration of VOCs emissions tends to be higher at the raw mill on rather than the raw mill off. At the raw mill on, concentration of total volatile organic carbon (VOCs emission from cement kiln stack feeding Solid AFR 1, biomass, Solid AFR 2, and mixture of Solid AFR and biomass is 16.18 mg/Nm3, 16.15 mg/Nm3, 9.02 mg/Nm3, and 14.11 mg/Nm3 respectively. The utilization of biomass resulted in the lower fraction of benzene and the higher fraction of xylenes in the total VOCs emission. Operating conditions such as thermal substitution rate, preheater temperature, and kiln speed are also likely to affect BTEX emissions.

  12. Theoretical & Experimental Studies of Elementary Particles

    Energy Technology Data Exchange (ETDEWEB)

    McFarland, Kevin [Univ. of Rochester, NY (United States)

    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

  13. Experimental studies on urea degradation in seawater

    Digital Repository Service at National Institute of Oceanography (India)

    Rajendran, A.; Joseph, T.; Reddy, C.V.G.

    The rate of urea degradation in seawater was studied under various conditions and the kinetics of urea degradation was evaluated. Urea decomposition experiments showed that the rates and quantity of ammonium oxidation were slower in the relatively...

  14. [Experimental study of a gentamycin ointment].

    Science.gov (United States)

    Kagan, E Z; Vasil'ev, V K; Bykova, M A; Berezina, E K

    1978-03-01

    Technology of 0.1 per cent gentamicin ointment production was developed. The ointment base consisted of vaseline and parafin (95:5). Pharmacokinetics and innocuousness of the gentamicin ointment were studied. It was shown that the ointment provided gentamicin diffusion through the skin utegument during a long period of time. Histological studies showed no local irritating effect of the ointment on the skin in its local use.

  15. 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 reporting...

  16. 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, (1-methylethyl)(2...

  17. 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 to...

  18. Experimental study of yttrium barium copper oxide superconducting ...

    Indian Academy of Sciences (India)

    667–676. Experimental study of yttrium barium copper oxide ... In the present study, torsional strain dependence of the critical current of the coated conductor is investigated experimentally for different current ramp rates. Again, the .... An empirical formula was proposed and established using a curve fit expressed in eq. (1).

  19. Modeling mechanisms of unusual benzene imine n6 adduct formation in carcinogenic reactions of arylnitrenium ions with adenosine.

    Science.gov (United States)

    Qi, Shi-Fei; Yang, Zhong-Zhi

    2007-12-21

    Reaction mechanisms of the unusual benzene imine N6 adduct formation in carcinogenic reactions of arylnitrenium ions with adenosine have been investigated with density functional theory (DFT) and high-level ab initio methods. The DFT calculations indicate that the reaction pathways initiated by attack of adenine at the ortho C site of 4-biphenylylnitrenium ion are favored. However, high-level MP2 and QCISD calculations provide a contrary conclusion, that is the reaction pathways initiated by attack of adenine at the para C site of 4-biphenylylnitrenium ion are more feasible. Comparing with experimental results, the conclusion from high-level ab initio calculations is ultimately supported. The present study makes a theoretical prediction on the final products in the studied reaction, which is in agreement with experimental observations. In addition, this study provides some inspirations to the attacks of arylnitrenium ions at amino group of purines and pyrimidines in similar carcinogenic reactions.

  20. Experimental studies of auroral arc generators

    Energy Technology Data Exchange (ETDEWEB)

    Suszcynsky, D.M.; Borovsky, J.E.; Thomsen, M.F. [and others

    1997-08-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). An all-sky video camera system was deployed in Eagle, Alaska at the foot of the magnetic field line that threads geosynchronous satellite 1989-046 as part of a campaign to study correlations of ground-based auroral activity with satellite-based plasma and energetic particle measurements. The overall intent of the project was to study magnetosphere-ionosphere coupling as it relates to the aurora, and, in particular, to look for signatures that may help to identify various auroral generator mechanism(s). During this study, our efforts were primarily directed towards identifying the generator mechanism(s) for pulsating aurora. Our data, though not conclusive, are found to support theories that propose a cyclotron resonance mechanism for the generation of auroral pulsations.

  1. Experimental study of oxidative DNA damage

    DEFF Research Database (Denmark)

    Loft, S; Deng, Xiaohong; Tuo, J

    1998-01-01

    of the use of 2-nitropropane as a model for oxidative DNA damage relate particularly to formation of 8-aminoguanine derivatives that may interfere with HPLC-EC assays and have unknown consequences. Other model compounds for induction of oxidative DNA damage, such as ferric nitriloacetate, iron dextran...... studies provide powerful tools to investigate agents inducing and preventing oxidative damage to DNA and its role in carcinogenesis. So far, most animal experiments have concerned 8-oxodG and determination of additional damaged bases should be employed. An ideal animal model for prevention of oxidative......Animal experiments allow the study of oxidative DNA damage in target organs and the elucidation of dose-response relationships of carcinogenic and other harmful chemicals and conditions as well as the study of interactions of several factors. So far the effects of more than 50 different chemical...

  2. 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

  3. Three coordination compounds based on benzene tetracarboxylate ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 129; Issue 8. Three coordination compounds based on benzene tetracarboxylate ligand: syntheses, structures, thermal behaviors and luminescence properties. YUNLONG WU CHANGKUN XIA JUN QIAN JIMIN XIE. REGULAR ARTICLE Volume 129 Issue 8 August ...

  4. 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.

  5. Organocalcium-mediated nucleophilic alkylation of benzene.

    Science.gov (United States)

    Wilson, Andrew S S; Hill, Michael S; Mahon, Mary F; Dinoi, Chiara; Maron, Laurent

    2017-12-01

    The electrophilic aromatic substitution of a C-H bond of benzene is one of the archetypal transformations of organic chemistry. In contrast, the electron-rich π-system of benzene is highly resistant to reactions with electron-rich and negatively charged organic nucleophiles. Here, we report that this previously insurmountable electronic repulsion may be overcome through the use of sufficiently potent organocalcium nucleophiles. Calcium n -alkyl derivatives-synthesized by reaction of ethene, but-1-ene, and hex-1-ene with a dimeric calcium hydride-react with protio and deutero benzene at 60°C through nucleophilic substitution of an aromatic C-D/H bond. These reactions produce the n- alkyl benzenes with regeneration of the calcium hydride. Density functional theory calculations implicate an unstabilized Meisenheimer complex in the C-H activation transition state. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  6. 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.

    2011-01-01

    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-butadiene 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. PMID:21187430

  7. 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.

  8. Experimental studies of actinides in molten salts

    International Nuclear Information System (INIS)

    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

  9. Experimental study on (vapor + liquid) equilibria of ternary systems of hydrocarbons/ionic liquid using headspace gas chromatography

    International Nuclear Information System (INIS)

    Mokhtarani, Babak; Valialahi, Leila; Heidar, Kurosh Tabar; Mortaheb, Hamid Reza; Sharifi, Ali; Mirzaei, Mojtaba

    2012-01-01

    Highlights: ► The ionic liquid [Omim][SCN] is considered as an appropriate entrainer for separation of five binary hydrocarbon systems. ► VLE data for the ternary systems consisting [Omim][SCN] and hydrocarbons were measured using headspace gas chromatography. ► The experimental VLE data are correlated using the thermodynamic model of NRTL with a good accuracy. ► The experimental results are compared with the VLE data using other ionic liquids as the entrainer. ► [Omim][SCN] can significantly improve the separation factors of these systems. - Abstract: (Vapor + liquid) equilibrium (VLE) data for ternary systems of (hexane + benzene), (hexane + cyclohexane), (benzene + cyclohexane), (1-hexene + cyclohexane), and (1-hexene + benzene) with an ionic liquid were measured by headspace gas chromatography. The applied ionic liquid 1-methyl 3-octylimidazolium thiocyanate, [Omim][SCN], acts as an entrainer. The comparison of the measured VLE data with the equilibrium data for the binary mixtures without ionic liquid show that [Omim][SCN] significantly improves the separation factor of these systems. The NRTL thermodynamic model is applied for correlating the experimental data. The modeling results show the NRTL model can correlate the experimental data with a good accuracy.

  10. Diallyl trisulfide (DATS) suppresses benzene-induced cytopenia by modulating haematopoietic cell apoptosis.

    Science.gov (United States)

    Han, Wenting; Wang, Shuo; Jiang, Lulu; Wang, Hui; Li, Ming; Wang, Xujing; Xie, Keqin

    2017-12-01

    Benzene is a well-known occupational and environmental toxicant associated with cytopenia, which is characterized by a disorder in the peripheral blood cell counts. However, no effective preventive strategy has been developed yet to tackle the exposure to benzene in daily life. The aim of this study was to evaluate the protective effects of diallyl trisulfide (DATS) on benzene-induced haematopoietic damage and to reveal its potential mechanisms of action. In our study, male Sprague-Dawley rats were divided into six groups. Rats were administered with benzene (1.3 g/kg BW by gavage) to establish the benzene poisoning model, while the DATS treatment groups were treated with benzene plus DATS (15 mg/kg, 30 mg/kg, 45 mg/kg, respectively, by gavage) for 28 days. Our results demonstrated that the counts of peripheral blood WBC and RBC decreased to 31.0% and 79.2%, respectively, in the benzene poisoning model group compared to the control. However, blood cell counts were restored by DATS treatment (30 mg/kg, 45 mg/kg). The apoptosis rates of peripheral blood mononuclear cells (PBMCs) and bone marrow cells (BMCs) were increased to 274% and 284%, respectively, following benzene exposure. Furthermore, expression levels of Bcl-2, PI3K and p-Akt were downregulated and those of Bax were upregulated in both cell types. Moreover, the oxidative parameters (oxygen species, malonaldehyde) were significantly increased, while the non-enzymatic GSH/GSSG ratios and the activities of enzymatic antioxidants (superoxide dismutase, glutathione peroxidase and catalase) were decreased. Interestingly, DATS treatment can restore the WBC number by 267.1% and 304.8% while RBC number by 108.6% and 117.7% in 30,45 mg/k DATS treated groups. In summary, we demonstrated that benzene-induced cytopenia was related to the apoptosis of PBMCs and BMCs, and DATS treatment could prevent benzene-induced cytopenia by suppressing oxidative stress-mediated cell apoptosis via the PI3K/Akt pathway. Copyright

  11. An Experimental Study of the Relationship between ...

    African Journals Online (AJOL)

    ... Test. It was predicted that the degree of separation of representational systems is significantly related to field dependence/independence. The results of this preliminary study are interpreted to indicate that the degree of separation of the bilingual's representational systems may be related to his/her degree of psychological ...

  12. EXPERIMENTAL STUDY OF THE PRODUCTION OF SOLAR ...

    African Journals Online (AJOL)

    Centre de développement des Energies Renouvelables, Alger, Algérie. Received: 01 February 2010 / Accepted: 02 June 2010 / Published online: 30 June 2010. ABSTRACT. Hydrogen is a sustainable fuel option and one of the potential solutions for the current energy and environmental problems. In this study hydrogen is ...

  13. Litigation and audit quality; two experimental studies

    NARCIS (Netherlands)

    Dijk, M. van

    1998-01-01

    This study examines the effect of litigation risk on auditors' willingness to yield to management pressure and to omit audit steps of the audit program in case of budget pressure. The results show that litigation risk has a significant impact on audit quality.

  14. Incisional Hernia: An Experimental and Clinical Study

    NARCIS (Netherlands)

    M. van 't Riet (Martijne)

    2004-01-01

    markdownabstract__Abstract__ Incisional hernia is one of the most common long-term complications of abdominal surgery. In prospective studies with sufficient follow-up, incidences of incisional hernia after laparotomy up to 20% are reported. Incisional hernia can be defined as an internal

  15. Experimental Study of Flow Through Carotid Aneurysms

    Science.gov (United States)

    Masoomi, Faezeh; Mejia-Alvarez, Ricardo

    2017-11-01

    There is evidence that traditional endovascular techniques like coiling are not effective for treatment of wide-neck cerebral aneurysms. Flow Diverter Stents (FDS) have emerged as promising devices for treating complex aneurysms since they enable treatment of aneurysms that were considered untreatable before. Recent studies suggest a number of associated risks with FDS, including in-stent thrombosis, perianeurysmal edema, delayed hemorrhage, and perforator occlusions. Chong et al. simulated hemodynamic behavior using patient-specific data. From their study, it is possible to infer that the standard deviation of energy loss could be a good predictor for intervention success. The aim of this study is to investigate the flow in models of cerebral aneurysms before and after FDS insertion using PIV. These models will be based on actual clinical studies and will be fabricated with advanced additive manufacturing techniques. These data will then be used to explore flow parameters that could inform the likelihood of post-intervention aneurysm rupture, and help determine FDS designs that better suit any particular patient before its procedure.

  16. CONTRIBUTION TO THE EXPERIMENTAL STUDY OF THE ...

    African Journals Online (AJOL)

    31 déc. 2010 ... This study aims to investigate the threshold-controlled hydraulic jump, moving in channel profile 'U' fully rough for a ... 'LARHYSS, University of Biskra. Key words: Hydraulic jump, channal-shaped in U, stilling basin, channel bottom rough. 1. ..... [7] Hager W. H. J. Hydraulic Engineering. 1989, 115, 667-675.

  17. Experimental Study on Gastric Juice Secretion by ...

    African Journals Online (AJOL)

    管理平台

    2012-05-29

    May 29, 2012 ... reduced (P < 0.05) when acupuncture at zusanli was applied after treatment with cimetidine. Therefore, our study shows that when electroacupuncture at zusanli is applied, the gastric electrical frequency increased and gastric electrical amplitude reduced, while the flux of gastric juice secretion increased.

  18. Self-diffusion in benzene-toluene and benzene-cyclohexane solutions

    International Nuclear Information System (INIS)

    Reimschuessel, W.; Hawlicka, E.

    1977-01-01

    The self-diffusion in benzene-toluene and benzene-cyclohexane solutions have been measured at different temperatures. The capillary-cell method was employed. The activation parameters of self-diffusion for the systems are presented. The data have been used to test the validity of various diffusion equations proposed in the literature. The hypothesis that the self-diffusion was realized by movement of aggregates of molecules is suggested. (orig.) [de

  19. Experimental study of highly viscous impinging jets

    International Nuclear Information System (INIS)

    Gomon, M.

    1998-12-01

    The objective of this research is to study the behavior of highly viscous gravity-driven jets filling a container. Matters of interest are the formation of voids in the fluid pool during the filling process and the unstable behavior of the fluid in the landing region which manifests itself as an oscillating motion. The working fluids used in this research are intended to simulate the flow behavior of molten glass. Qualitative and quantitative results are obtained in a parametric study. The fraction of voids present in the fluid pool after the filling of the container is measured for different parameter values of viscosity and mass flow rate. Likewise, frequencies of the oscillating jet are measured. Results are inconclusive with regard to a correlation between parameter settings and void fractions. As for frequencies, power law correlations are established

  20. Color transparency in the deuterium: experimental study

    International Nuclear Information System (INIS)

    Voutier, E.; Pastor, A.; Russew, Th.; Breton, V.; Mathiot, J.F.; Laget, J.M.; Marchand, C.; Marroncle, J.

    1996-01-01

    The description of exclusive reactions at high momentum transfer relies on the Hard Scattering Picture of Quantum Chromodynamics. Particularly, the electromagnetic interaction with a nucleon at high enough Q 2 is predicted to select small transverse size components of the valence wave function. The evolution of these small components in a nuclear medium is characterized by a reduced interaction significant of the occurrence of color transparency. The present report is a feasibility study of a color transparency experiment in the deuterium in the context of the ELFE/DESY project. It is shown that the availability of such an electron facility allows uniquely to study accurately color transparency and therefore contributes to the understanding of the non-perturbative mechanisms of Quantum Chromodynamics. (authors)

  1. Theoretical and experimental studies of thermolysin inhibition

    OpenAIRE

    Wuxiuer, Yimingjiang

    2008-01-01

    Zinc-metalloproteinases play a key role in the biosythesis and metabolism of different bioactive peptides. As a member of zinc-metalloproteinases, thermolysin has served as a model system to study the inhibition mechanism of other metalloproteinases. Inhibitors of thermolysin have considerable potential as therapeutic agents. In the present master thesis, docking calculations were performed and reported for 25 potent non-peptidal thermolysin inhibitors retrieved from literatures. Docking sof...

  2. UV-visible and Raman investigations of matrix isolated adducts between metal vapors of chromium and benzene: selective photo-irradiations effects

    Science.gov (United States)

    Dalibart, M.; Derouault, J.

    1989-03-01

    The UV-visible absorption and the Raman spectra of chromium vapors trapped either in Ar-benzene mixtures or in neat benzene have been investigated. The data give evidence for the formation of the well-known dibenzene chromium sandwich complex but show also the formation of benzene complexes with the dimer Cr2 and with the cluster Cr3 photo-irradiations effects have been studied.

  3. Experimental studies in non-equilibrium physics

    Science.gov (United States)

    Cressman, John Robert, Jr.

    This work is a collection of three experiments aimed at studying different facets of non-equilibrium dynamics. Chapter I concerns strongly compressible turbulence, which turns out to be very different from incompressible turbulence. The focus is on the dispersion of contaminants in such a flow. This type of turbulence can be studied, at very low mach number, by measuring the velocity fields of particles that float on a turbulently stirred body of water. It turns out that in the absence of incompressibility, the turbulence causes particles to cluster rather than to disperse. The implications of the observations are far reaching and include the transport of pollutants on the oceans surface, phytoplankton growth, as well as industrial applications. Chapter II deals with the effects of polymer additives on drag reduction and turbulent suppression, a well-known phenomenon that is not yet understood. In an attempt to simplify the problem, the effects of a polymer additive were investigated in a vortex street formed in a flowing soap film. Measurements suggest that an increase in elongational viscosity is responsible for a substantial reduction in periodic velocity fluctuations. This study also helps to illuminate the mechanism responsible for vortex separation in the wake of a bluff body. Chapter III describes an experiment designed to test a theoretical approach aimed at generalizing the classical fluctuation dissipation theorem (FDT). This theorem applies to systems driven only slightly away from thermal equilibrium, whereas ours, a liquid crystal under-going electroconvection, is so strongly driven, that the FDT does not apply. Both theory and experiment focus on the flux in global power fluctuations. Physical limitations did not permit a direct test of the theory, however it was possible to establish several interesting characteristics of the system: the source of the fluctuations is the transient defect structures that are generated when the system is driven hard

  4. Experimental study of a solar still

    Science.gov (United States)

    Hassoun, Z. Sari; Aliane, K.; Berrezoug, H. I.

    2016-07-01

    This work concerns the study of a solar distiller. Particular attention is paid to the different operating characteristics such as: temperature, global and internal efficiency, performance and the performance factor during the distillation process. We have also established the overall heat balance in transition. A series of tests was carried out during the summer under the sea water to see the evolution of different parameters of the distiller. The daily output of solar still is 1.8litre / day. All the dissolved solids (TDS), conductivity and pH of the water were measured.

  5. 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...... system with two computers each equipped with a frame grabber card. In the search for the best experimentalmethods we have revised the concept of local homogeneity and derived a law for the velocity--acceleration structure function. A second by-product of this effort is a relatively simple derivation...

  6. Experimental study of isovector spin sum rules

    International Nuclear Information System (INIS)

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

    2008-01-01

    We present the Bjorken integral extracted from Jefferson Lab experiment EG1b for 0.05 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 γ 0 . Although this quantity provides a robust test of Chiral Perturbation Theory, our data disagree with the calculations

  7. Experimental and modelling studies of infiltration

    International Nuclear Information System (INIS)

    Giudici, M.

    2004-01-01

    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

  8. Theoretical and experimental study of thermoacoustic engines

    Science.gov (United States)

    Raspet, Richard; Bass, Henry E.; Arnott, W. P.

    1992-12-01

    A three year study of thermoacoustic engines operating as prime movers and refrigerators was completed. The major thrust of this effort was the use and theoretical description of ceramic honeycomb structures as the active element in thermoacoustic engines. An air-filled demonstration prime mover was constructed and demonstrated at Acoustical Society of America and IEE meetings. A helium-filled test prime mover was designed and built an is being employed in studies of the threshold of oscillation as a function of temperature difference and pressure. In addition, acoustically based theories of the thermoacoustic engine have been developed and tested for a parallel plate stack at the Naval Postgraduate School and for a honeycomb stack at the University of Mississippi. Most of this work is described in detail in the attached publications. In this report we will give an overview of the research completed to date and its relationship to work performed at the Naval Postgraduate School and to future work at the University of Mississippi.

  9. Field experimentation in isotope-aided studies

    International Nuclear Information System (INIS)

    Zapata, F.

    1990-01-01

    Isotopic-aided studies involve the application of isotopically labelled fertilizer as tracers for the quantitative and precise determination of the fate of specific nutrient elements in the soil/plant system. The planning of isotopic-aided studies requires a different approach from that followed in the design of normal fertilizer trials because of the cost and supply of isotopically labelled materials, the use of highly specialized equipment and the need for skillful trained staff in the use of isotope techniques both in the field/greenhouse and the laboratory. This report is intended to highlight the main points to be considered while applying those techniques in the field or greenhouse. It has been well established that nuclear techniques are a powerful tool in agricultural research. One should take advantage of the use of such techniques if the following criteria are met: The isotope method is the only way to solve a particular question or to obtain a specific piece of information. There are other methods available for such a purpose but the nuclear method provides a direct and quick means to obtain the needed information resulting in higher economic return

  10. An experimental study of coal gasification

    Energy Technology Data Exchange (ETDEWEB)

    Dervisoglu, M.; Hortacsu, O. [Bogazici University, Istanbul (Turkey). Dept. of Chemical Engineering

    1998-12-01

    The paper describes 64 experiments carried out on a 2 m diameter gas generator for a ceramics factory to study the effects of air-supply pressure, steam-saturation temperature and generator-gas exit temperature on fuel heating value. Gaseous fuels with heating values ranging from 1100 to 1400 cal/liter were obtained. The heating value of the gas could be raised by up to 27% by maintaining the three process variables close to their optimum values, i.e. air supply pressure 43 cm of H{sub 2}O, steam-saturation temperature of 55{degree}C, and generator gas-exit temperature of 160{degree}C.

  11. 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.

  12. Experimental study of diffuse auroral precipitations

    International Nuclear Information System (INIS)

    Mouaia, K.

    1983-01-01

    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 [fr

  13. Experimental study on the adiabatic shear bands

    International Nuclear Information System (INIS)

    Affouard, J.

    1984-07-01

    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 [fr

  14. ESP Teaching for Tourism. An Experimental Study

    Directory of Open Access Journals (Sweden)

    Buzarna-Tihenea (Gălbează Alina

    2017-01-01

    Full Text Available This paper is focused on those teaching and learning methods and techniques which can improve the practical use of English for work-related purposes, this giving the students the opportunity to develop their language skills by means of attractive, motivating and useful learning activities. The paper aims at providing an in-depth knowledge about ways of studying and applying English for Specific Purposes in the Tourism field, as well as types of activities to be used in the classroom in order to assist learners overcome language difficulties. It is of great importance to emphasize the specific tasks and strategies used while teaching ESP for Tourism classes, strategies that differ from the ones used in a traditional English language classroom. The main purpose of all these ESP methods and approaches is to prepare students for their future jobs so that they can perform effectively in their area of work.

  15. Experimental study of a capillary discharge

    International Nuclear Information System (INIS)

    Kania, D.R.; Jones, L.A.

    1984-01-01

    A Z-pinch plasma can be ohmically heated to kilovolt temperatures if instabilities can be prevented and the amount of mass heated is held fixed. The gas embedded laser initiated Z-pinch was an attempt to do this. It was found that the disruptive instabilities did not occur, but that the discharge column accreted mass, probably because of the strong shock which ionizes the embedding gas. In an attempt to overcome this problem a capillary channel has been formed in an insulator so that a solid replaces the embedding gas. The authors have studied the plasma formed by discharging a Marx-water line system through an evacuated 2 cm long 10-25 μm diameter capillary in polyethylene. The Marx-water line system used was a 72 kJ - 600 kV Marx bank which is capable of pulse charging a 1Ω-90 ns water line to 900 kV

  16. Mortar alteration: experimental study and ancient analogues

    International Nuclear Information System (INIS)

    Rassineux, Francois

    1987-01-01

    As the durability of cemented matrices is a matter of great importance in numerous domains, notably for the long term reliability of surface storages of radioactive wastes, the objective of this research thesis is to define mechanisms of evolution of cemented matrices when in contact with diluted aqueous solutions. The author notably studied the influence of the lixiviation mode on the evolution of two mortars having different compositions (pH, CO 2 pressure, system containment, and cement mineralogical nature appear to be the main governing parameters), the alteration (dissolution is the prevailing process in the interaction between cemented matrices and a diluted solution such as rain water), and ancient binders (archaeological binders containing mineral phases such as hydrated calcium silicates or hydro-grossulars). The obtained results lead to the definition of alteration mechanisms in modern cements, and highlight factors governing the durability of these materials when submitted to meteoric alteration [fr

  17. Experimental and clinical studies with intraoperative radiotherapy

    International Nuclear Information System (INIS)

    Sindelar, W.F.; Kinsella, T.; Tepper, J.; Travis, E.L.; Rosenberg, S.A.; Glatstein, E.

    1983-01-01

    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

  18. Preliminary experimental studies of waste coal gasification

    Energy Technology Data Exchange (ETDEWEB)

    Su, S.; Jin, Y.G.; Yu, X.X.; Worrall, R. [CSIRO, Brisbane, QLD (Australia). Advanced Coal Technology

    2013-07-01

    Coal mining is one of Australia's most important industries. It was estimated that coal washery rejects from black coal mining was approximately 1.82 billion tonnes from 1960 to 2009 in Australia, and is projected to produce another one billion tonnes by 2018 at the current production rate. To ensure sustainability of the Australian coal industry, we have explored a new potential pathway to create value from the coal waste through production of liquid fuels or power generation using produced syngas from waste coal gasification. Consequently, environmental and community impacts of the solid waste could be minimized. However, the development of an effective waste coal gasification process is a key to the new pathway. An Australian mine site with a large reserve of waste coal was selected for the study, where raw waste coal samples including coarse rejects and tailings were collected. After investigating the initial raw waste coal samples, float/sink testing was conducted to achieve a desired ash target for laboratory-scale steam gasification testing and performance evaluation. The preliminary gasification test results show that carbon conversions of waste coal gradually increase as the reaction proceeds, which indicates that waste coal can be gasified by a steam gasification process. However, the carbon conversion rates are relatively low, only reaching to 20-30%. Furthermore, the reactivity of waste coal samples with a variety of ash contents under N{sub 2}/air atmosphere have been studied by a home-made thermogravimetric analysis (TGA) apparatus that can make the sample reach the reaction temperature instantly.

  19. Experimental Studies of Electrothermal Plasma Gun

    International Nuclear Information System (INIS)

    Diab, F.B.A.

    2013-01-01

    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.

  20. A bioresorbable urethral stent. An experimental study.

    Science.gov (United States)

    Kemppainen, E; Talja, M; Riihelä, M; Pohjonen, T; Törmälä, P; Alfthan, O

    1993-05-01

    The aim of the present study was to examine the suitability of biodegradable polymers as materials for a urethral stent. A new urethral stent made of biodegradable self-reinforced poly-L-lactide (SR-PLLA) was implanted in 16 male rabbits after urethrotomy. Seven stents of stainless steel served as controls. The dimensions of the two types of stents were identical: length 15 mm, diameter 8.2 mm. The mechanical construction was a helical spiral. The SR-PLLA spiral was sustained with three microspirals, and the whole device was coated with DL-lactide to achieve an active initial tissue reaction and better tissue penetration. The SR-PLLA stent showed more favourable implantation properties than the steel one. Within 6 months all PLLA stents had implanted, and the tissue reaction around the stent material was minimal. The helical spiral of stainless steel induced a remarkable inflammatory reaction due to poor implantation properties. We suggest that biodegradable SR-PLLA is a promising material for a urethral stent to prevent re-stenosis of urethral strictures.

  1. EXPERIMENTAL STUDY OF MINIMUM IGNITION TEMPERATURE

    Directory of Open Access Journals (Sweden)

    Igor WACHTER

    2015-12-01

    Full Text Available The aim of this scientific paper is an analysis of the minimum ignition temperature of dust layer and the minimum ignition temperatures of dust clouds. It could be used to identify the threats in industrial production and civil engineering, on which a layer of combustible dust could occure. Research was performed on spent coffee grounds. Tests were performed according to EN 50281-2-1:2002 Methods for determining the minimum ignition temperatures of dust (Method A. Objective of method A is to determine the minimum temperature at which ignition or decomposition of dust occurs during thermal straining on a hot plate at a constant temperature. The highest minimum smouldering and carbonating temperature of spent coffee grounds for 5 mm high layer was determined at the interval from 280 °C to 310 °C during 600 seconds. Method B is used to determine the minimum ignition temperature of a dust cloud. Minimum ignition temperature of studied dust was determined to 470 °C (air pressure – 50 kPa, sample weight 0.3 g.

  2. Experimental study of acoustic vibration in BWRs

    International Nuclear Information System (INIS)

    Kumagai, Kosuke; Someya, Satoshi; Okamoto, Koji

    2009-01-01

    In recent years, the power uprate of Boiling Water Reactors have been conducted at several existing power plants as a way to improve plant economy. In one of the power uprated plants (117.8% uprates) in the United States, the steam dryer breakages due to fatigue fracture occurred. It is conceivable that the increased steam flow passing through the branches caused a self-induced vibration with the propagation of sound wave into the steam-dome. The resonance among the structure, flow and the pressure fluctuation resulted in the breakages. To understand the basic mechanism of the resonance, previous researches were done by a point measurement of the pressure and by a phase averaged measurement of the flow, while it was difficult to detect the interaction among them by the conventional method. In this study, Dynamic Particle Image Velocimetry (PIV) System was applied to investigate the effect of sound on natural convection and forced convection. Dynamic PIV system is the newest entrant to the field of fluid flow measurement. Its paramount advantage is the instantaneous global evaluation of conditions over plane extended across the whole velocity field. Also, to evaluate the coupling between the acoustic wave and structure (simulated as tuning fork vibrator in this experiment), in the resonance frequency of tuning fork vibrator, fluid behavior and the motion of tuning fork vibrator are measured simultaneously. (author)

  3. Injury Based on Its Study in Experimental Models

    Directory of Open Access Journals (Sweden)

    M. Mendes-Braz

    2012-01-01

    Full Text Available The present review focuses on the numerous experimental models used to study the complexity of hepatic ischemia/reperfusion (I/R injury. Although experimental models of hepatic I/R injury represent a compromise between the clinical reality and experimental simplification, the clinical transfer of experimental results is problematic because of anatomical and physiological differences and the inevitable simplification of experimental work. In this review, the strengths and limitations of the various models of hepatic I/R are discussed. Several strategies to protect the liver from I/R injury have been developed in animal models and, some of these, might find their way into clinical practice. We also attempt to highlight the fact that the mechanisms responsible for hepatic I/R injury depend on the experimental model used, and therefore the therapeutic strategies also differ according to the model used. Thus, the choice of model must therefore be adapted to the clinical question being answered.

  4. Markets and morals: an experimental survey study.

    Science.gov (United States)

    Elias, Julio J; Lacetera, Nicola; Macis, Mario

    2015-01-01

    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 relate these

  5. 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

  6. Experimental study of flow through compressor Cascade

    Directory of Open Access Journals (Sweden)

    Satyam Panchal

    2017-09-01

    Full Text Available The objective of this research work is to study the behaviour of flow at the inlet, within the blade passage and at the exit of a compressor cascade. For this purpose, a cascade with six numbers of aerofoil blades was designed and constructed. The cascade was fitted on the cascade test tunnel. Out of six blades two were instrumented for measuring the pressure distribution on the pressure and suction surface. The blades had a parabolic camber line, with a maximum camber position at 40% of the chord from the leading edge of the blade. The profile of the blade was C4, height of the blade was 160 mm, chord length was 80 mm, camber angle was 45° and stagger angle was 30°. Similarly, the length of the cascade was 300 mm, span was 160 mm, pitch was 60 mm, the actual chord of the cascade was 80 mm, the axial chord of the cascade was 70 mm, the stagger angle of the cascade was 30° and the pitch-chord ratio was 0.75. The data was taken and analyzed at −500% of the axial chord before the cascade, −25% of the axial chord before the leading edge, 25%, 50%, 75% and 150% of the axial chord from the leading edge of the blade. The readings were taken from the cascade wall to the mid span position along the pitch wise direction. The angle of incidence was also changed during the experiment and varied from i=−50°, −30°, −10° to 5°.

  7. Medical waste to energy: experimental study.

    Science.gov (United States)

    Arcuri, C; Luciani, F; Piva, P; Bartuli, F N; Ottria, L; Mecheri, B; Licoccia, S

    2013-04-01

    Although waste is traditionally assessed as a pollutant which needs to be reduced or lessened, its management is certainly necessary. Nowadays, biological fuel cells, through the direct conversion of organic matter to electricity using biocatalysts, represent a technology able to produce sustainable energy by means of waste treatment. This study aims to propose a mean to generate energy from blood and saliva, that are common risk-infectious medical waste. Material employed (purchased by Sigma-Aldrich) were: Glucose oxidase (GOx), Nafion perfluorinated resin solution at 5% in a mixture of lower aliphatic alcohols and water, Polyethylene oxide. Stock solutions of D (+) glucose were prepared in a 0.1 M phosphate buffer solution and stored at 4 °C for at least 24 h before use. Carbon cloth electrode ELAT HT 140 E-W with a platinum loading of 5 gm-2 was purchased by E-Tek. Electrospun Nafion fibers were obtained as follows. Scanning electron microscopy was used to characterize the electrode morphologies. In order to develop an effective immobilization strategy of GOx on the electrode surface, Nafion fibers (a fully fluorinated ion conducting polymer used as a membrane material in enzymatic fuel cells - EFC) were selected as immobilizing polymer matrix. In this work, exploiting the nafion fibers capability of being able to cathalize Gox activity, we have tried to produce an enzymatic fuel cell which could produce energy from the blood and the saliva within medical-dental waste. Medical waste refers to all those materials produced by the interaction among doctor and patient, such as blood and saliva. During our research we will try to complete an EFC prototype able to produce energy from blood and saliva inside the risk-infectious medical waste in order to contribute to the energy requirements of a consulting room.

  8. Markets and Morals: An Experimental Survey Study

    Science.gov (United States)

    Elias, Julio J.; Lacetera, Nicola; Macis, Mario

    2015-01-01

    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 relate

  9. 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.

  10. Characterization of Changes in Gene Expression and Biochemical Pathways at Low Levels of Benzene Exposure

    Science.gov (United States)

    Thomas, Reuben; Hubbard, Alan E.; McHale, Cliona M.; Zhang, Luoping; Rappaport, Stephen M.; Lan, Qing; Rothman, Nathaniel; Vermeulen, Roel; Guyton, Kathryn Z.; Jinot, Jennifer; Sonawane, Babasaheb R.; Smith, Martyn T.

    2014-01-01

    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. PMID:24786086

  11. Theoretical and Experimental Studies in Accelerator Physics

    Energy Technology Data Exchange (ETDEWEB)

    Rosenzweig, James [Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy

    2017-03-08

    . We note also that PBPL graduates remain as close elaborators for the program after leaving UCLA. The UCLA PBPL program is a foremost developer of on-campus facilities, such as the Neptune and Pegasus Laboratories, providing a uniquely strong environment for student-based research. In addition, the PBPL is a strong user of off-campus national lab facilities, such as SLAC FACET and NLCTA, and the BNL ATF. UCLA has also vigorously participated in the development of these facilities. The dual emphases on off- and on-campus opportunities permit the PBPL to address in an agile way a wide selection of cutting-edge research topics. The topics embraced by this proposal illustrate this program aspect well. These include: GV/m dielectric wakefield acceleration/coherent Cerenkov radiation experiments at FACET (E-201) and the ATF; synergistic laser-excited dielectric accelerator and light source development; plasma wakefield (PWFA) experiments on “Trojan horse” ionization injection (FACET E-210), quasi-nonlinear PWFA at BNL and the production at Neptune high transformer ratio plasma wakes; the inauguration of a new type of RF photoinjector termed “hybrid” at UCLA, and application to PWFA; space-charge dominated beam and cathode/near cathode physics; the study of advanced IFEL systems, for very high energy gain and utilization of novel OAM modes; the physcis of inverse Compton scattering (ICS), with applications to e+ production and γγ colliders; electron diffraction; and advanced beam diagnostics using coherent imaging techniques. These subjects are addressed under the leadership of PBPL director Prof. James Rosenzweig in Task A, and Prof. Pietro Musumeci in Task J, which was initiated following his OHEP Outstanding Junior Investigator award.

  12. Experimental studies on caisson-type porous seawalls

    Science.gov (United States)

    Zhu, Shutang; Chwang, A. T.

    2002-08-01

    This paper presents experimental studies on the reflection characteristics of caisson-type porous seawalls under designed wave conditions. The results of physical model experiments are plotted and discussed. Comparisons between experimental results and analytical predictions are also made and the agreement is found to be very good.

  13. Experimental studies on an indigenous coconut shell based ...

    Indian Academy of Sciences (India)

    Experimental studies are carried out to characterize an indigenous, coconut shell based, activated carbon suitable for storage of natural gas. Properties such as BET surface area, micropore volume, average pore diameter and pore size distribution are obtained by using suitable instruments and techniques. An experimental ...

  14. Molecular dynamics simulation of gas-phase ozone reactions with sabinene and benzene.

    Science.gov (United States)

    Ridgway, H F; Mohan, B; Cui, X; Chua, K J; Islam, M R

    2017-06-01

    Gas-phase reactions of ozone (O 3 ) with volatile organic compounds were investigated both by experiment and molecular simulations. From our experiments, it was found ozone readily reacts with VOC pure components and reduces it effectively. By introducing ozone intermittently, the reaction between VOC and ozone is markedly enhanced. In order to understand the relationship between intermediate reactions and end products, ozone reaction with benzene and alicyclic monoterpene sabinene were simulated via a novel hybrid quantum mechanical/molecular mechanics (QM/MM) algorithm that forced repeated bimolecular collisions. Molecular orbital (MO) rearrangements (manifested as bond dissociation or formation), resulting from the collisions, were computed by semi-empirical unrestricted Hartree-Fock methods (e.g., RM1). A minimum of 975 collisions between ozone and targeted organic species were performed to generate a distribution of reaction products. Results indicated that benzene and sabinene reacted with ozone to produce a range of stable products and intermediates, including carbocations, ring-scission products, as well as peroxy (HO 2 and HO 3 ) and hydroxyl (OH) radicals. Among the stable sabinene products observed included formaldehyde and sabina-ketone, which have been experimentally demonstrated in gas-phase ozonation reactions. Among the benzene ozonation products detected composed of oxygen mono-substituted aromatic C 6 H 5 O, which may undergo further transformation or rearrangement to phenol, benzene oxide or 2,4-cyclohexadienone; a phenomenon which has been experimentally observed in vapor-phase photocatalytic ozonation reactions. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Indicators of benzene emissions and exposure in Bangkok street

    International Nuclear Information System (INIS)

    Leong, S.T.; Laortanakul, Preecha

    2003-01-01

    Ambient benzene measurements were conducted for the first time at four air monitoring sites in the Bangkok metropolitan region (BMR), from January to December 2001. Analytical results show that the mean benzene concentrations range from 42.4 μg/m 3 at the Din Daeng urban site to 15.1 μg/m 3 at the Chaeng Wattana suburban site. The monitoring results show that at a larger distance from the roadside or a higher level from the street surface, the level of benzene decreases. Analysis of the ambient benzene concentrations was carried out with reference to meteorological influences and traffic density. In traffic analysis, the combined effects of street topography and traffic flows established high impact on the overall benzene concentration in Bangkok. Statistical analysis shows good correlations of blood benzene levels and trans, trans-muconic acid with ambient benzene and demonstrated substantial exposure from traffic

  16. Benzene and naphthalene in air and breath as indicators of exposure to jet fuel

    Science.gov (United States)

    Egeghy, P; Hauf-Cabalo, L; Gibson, R; Rappaport, S

    2003-01-01

    Aims: To estimate exposures to benzene and naphthalene among military personnel working with jet fuel (JP-8) and to determine whether naphthalene might serve as a surrogate for JP-8 in studies of health effects. Methods: Benzene and naphthalene were measured in air and breath of 326 personnel in the US Air Force, who had been assigned a priori into low, moderate, and high exposure categories for JP-8. Results: Median air concentrations for persons in the low, moderate, and high exposure categories were 3.1, 7.4, and 252 µg benzene/m3 air, 4.6, 9.0, and 11.4 µg benzene/m3 breath, 1.9, 10.3, and 485 µg naphthalene/m3 air, and 0.73, 0.93, and 1.83 µg naphthalene/m3 breath, respectively. In the moderate and high exposure categories, 5% and 15% of the benzene air concentrations, respectively, were above the 2002 threshold limit value (TLV) of 1.6 mg/m3. Multiple regression analyses of air and breath levels revealed prominent background sources of benzene exposure, including cigarette smoke. However, naphthalene exposure was not unduly influenced by sources other than JP-8. Among heavily exposed workers, dermal contact with JP-8 contributed to air and breath concentrations along with several physical and environmental factors. Conclusions: Personnel having regular contact with JP-8 are occasionally exposed to benzene at levels above the current TLV. Among heavily exposed workers, uptake of JP-8 components occurs via both inhalation and dermal contact. Naphthalene in air and breath can serve as useful measures of exposure to JP-8 and uptake of fuel components in the body. PMID:14634191

  17. Bioremediation of benzene-, MTBE- and ammonia-contaminated groundwater with pilot-scale constructed wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, Eva M., E-mail: eva.seeger@ufz.de [Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany); Kuschk, Peter; Fazekas, Helga [Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany); Grathwohl, Peter [Center of Applied Geoscience, University of Tuebingen, Hoelderlinstr. 12, 72074 Tuebingen (Germany); Kaestner, Matthias [Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany)

    2011-12-15

    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/m{sup 2}/d, 97/112 mg/m{sup 2}/d, and 1167/1342 mg/m{sup 2}/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.

  18. 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.; Emily Majcher,; Brayton, Michael J.; Raffensperger, Jeff P.; Cozzarelli, Isabelle M.

    2015-01-01

    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

  19. Study of TXRF experimental system by Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Ana Cristina M.; Leitao, Roberta G.; Lopes, Ricardo T., E-mail: ricardo@lin.ufrj.br [Nuclear Instrumentation Laboratory, Nuclear Engineering Program/COPPE Federal University of Rio de Janeiro (UFRJ), RJ (Brazil); Anjos, Marcelino J., E-mail: marcelin@uerj.br [State University of Rio de Janeiro (UERJ/IFADT/DFAT), RJ (Brazil); Conti, Claudio C., E-mail: ccconti@ird.gov.br [Instituto de Radioprotecao e Dosimetria, (IRD/CNEN-RJ), Rio de janeiro, RJ (Brazil)

    2011-07-01

    The Total-Reflection X-ray Fluorescence (TXRF) technique offers unique possibilities to study the concentrations of a wide range of trace elements in various types of samples. Besides that, the TXRF technique is widely used to study the trace elements in biological, medical and environmental samples due to its multielemental character as well as simplicity of sample preparation and quantification methods used. In general the TXRF experimental setup is not simple and might require substantial experimental efforts. On the other hand, in recent years, experimental TXRF portable systems have been developed. It has motivated us to develop our own TXRF portable system. In this work we presented a first step in order to optimize a TXRF experimental setup using Monte Carlo simulation by MCNP code. The results found show that the Monte Carlo simulation method can be used to investigate the development of a TXRF experimental system before its assembly. (author)

  20. Subclinical effects of groundwater contaminants. Pt. 3. Effects of repeated oral exposure to combinations of benzene and toluene on immunologic responses in mice

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, G.C.; Parker, R.D.R. (Utah State Univ., Logan (USA). Dept. of Biology); Sharma, R.P.; Hughes, B.J. (Utah Univ., Logan, UT (USA). Dept. of Animal, Dairy and Veterinary Sciences)

    1990-06-01

    Toxicity of environmental pollutants may be expressed as combined effects of chemicals. Benzene, a proven hematotoxic agent, frequently occurs with toluene in cocontaminated groundwater. Groups of CD-1 male mice were exposed continuously for 4 weeks to benzene (166 mg/l), toluene (80 and 325 mg/l), and combinations of benzene (166 mg/l) + toluene (80 mg/l or 325 mg/l) in drinking water. Benzene-induced anemia was alleviated by simultaneous toluene treatment. Leukopenia and lymphopenia were observed in the case of benzene only and benzene + toluene (80 mg/l)-treated mice. The cytopenia, however, was less severe in the benzen + toluene (325 mg/l)-treated group. Immunotoxicity induced by benzene treatment alone was characterized by involution of thymic mass and suppressions of both B- and T-cell mitogeneses, mixed lymphocyte culture response to alloantigens, the tumor lytic ability of cytotoxic T-lymphocytes as determined by {sup 51}Cr-release assay, and antibody production response to T-dependent antigen (sheep red blood cells). IL-2 secretion by Con A-stimulated mouse T-cells was decreased in the benzene-treated group. Toluene (325 mg/l) completely inhibited these adverse effects when it was coadministered with benzene, while the low dose of toluene (80 mg/l) did not protect against benzene-induced depressions of immune functions. Toluene administered alone at levels up to 325 mg/l showed no abvious immunotoxic effects. Results of this study demonstrated that toluene, in sufficient amounts, has an antagonistic effect on benzene immunotoxicity. (orig.).

  1. VUV photo-oxidation of gaseous benzene combined with ozone-assisted catalytic oxidation: Effect on transition metal catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Haibao, E-mail: seabao8@gmail.com [School of Environmental Science and Engineering, Sun Yat-Sen University (China); Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University) (China); Lu, Haoxian; Zhan, Yujie; Liu, Gaoyuan; Feng, Qiuyu; Huang, Huiling; Wu, Muyan; Ye, Xinguo [School of Environmental Science and Engineering, Sun Yat-Sen University (China)

    2017-01-01

    Graphical abstract: Mn nanoparticles are highly dispersed on ZSM-5 and most efficient in benzene degradation in the VUV-OZCO process. - Highlights: • Vacuum UV irradiation is well combined with O{sub 3} catalytic oxidation. • O{sub 3} byproducts was used to enhance catalytic oxidation of VOCs. • Mn/ZSM-5 achieved the best catalytic activity for benzene degradation. - Abstract: Volatile organic compounds (VOCs) cause the major air pollution concern. In this study, a series of ZSM-5 supported transition metals were prepared by impregnation method. They were combined with vacuum UV (VUV) photo-oxidation in a continuous-flow packed-bed reactor and used for the degradation of benzene, a typical toxic VOCs. Compared with VUV photo-oxidation alone, the introduction of catalysts can greatly enhance benzene oxidation under the help of O{sub 3}, the by-products from VUV irradiation, via ozone-assisted catalytic oxidation (OZCO). The catalytic activity of transition metals towards benzene oxidation followed the order: Mn > Co > Cu > Ni > Fe. Mn achieved the best catalytic activity due to the strongest capability for O{sub 3} catalytic decomposition and utilization. Benzene and O{sub 3} removal efficiency reached as high as 97% and 100% after 360 min, respectively. O{sub 3} was catalytically decomposed, generating highly reactive oxidants such as ·OH and ·O for benzene oxidation.

  2. Metatranscriptome of an Anaerobic Benzene-Degrading, Nitrate-Reducing Enrichment Culture Reveals Involvement of Carboxylation in Benzene Ring Activation

    Science.gov (United States)

    Luo, Fei; Gitiafroz, Roya; Devine, Cheryl E.; Gong, Yunchen; Hug, Laura A.; Raskin, Lutgarde

    2014-01-01

    The enzymes involved in the initial steps of anaerobic benzene catabolism are not known. To try to elucidate this critical step, a metatranscriptomic analysis was conducted to compare the genes transcribed during the metabolism of benzene and benzoate by an anaerobic benzene-degrading, nitrate-reducing enrichment culture. RNA was extracted from the mixed culture and sequenced without prior mRNA enrichment, allowing simultaneous examination of the active community composition and the differential gene expression between the two treatments. Ribosomal and mRNA sequences attributed to a member of the family Peptococcaceae from the order Clostridiales were essentially only detected in the benzene-amended culture samples, implicating this group in the initial catabolism of benzene. Genes similar to each of two subunits of a proposed benzene-carboxylating enzyme were transcribed when the culture was amended with benzene. Anaerobic benzoate degradation genes from strict anaerobes were transcribed only when the culture was amended with benzene. Genes for other benzoate catabolic enzymes and for nitrate respiration were transcribed in both samples, with those attributed to an Azoarcus species being most abundant. These findings indicate that the mineralization of benzene starts with its activation by a strict anaerobe belonging to the Peptococcaceae, involving a carboxylation step to form benzoate. These data confirm the previously hypothesized syntrophic association between a benzene-degrading Peptococcaceae strain and a benzoate-degrading denitrifying Azoarcus strain for the complete catabolism of benzene with nitrate as the terminal electron acceptor. PMID:24795366

  3. Benzene Exposure Alters Expression of Enzymes Involved in Fatty Acid β-Oxidation in Male C3H/He Mice

    Directory of Open Access Journals (Sweden)

    Rongli Sun

    2016-10-01

    Full Text Available Benzene is a well-known hematotoxic carcinogen that can cause leukemia and a variety of blood disorders. Our previous study indicated that benzene disturbs levels of metabolites in the fatty acid β-oxidation (FAO pathway, which is crucial for the maintenance and function of hematopoietic and leukemic cells. The present research aims to investigate the effects of benzene on changes in the expression of key enzymes in the FAO pathway in male C3H/He mice. Results showed that benzene exposure caused reduced peripheral white blood cell (WBC, red blood cell (RBC, platelet (Pit counts, and hemoglobin (Hgb concentration. Investigation of the effects of benzene on the expression of FA transport- and β-oxidation-related enzymes showed that expression of proteins Cpt1a, Crat, Acaa2, Aldh1l2, Acadvl, Crot, Echs1, and Hadha was significantly increased. The ATP levels and mitochondrial membrane potential decreased in mice exposed to benzene. Meanwhile, reactive oxygen species (ROS, hydrogen peroxide (H2O2, and malondialdehyde (MDA levels were significantly increased in the benzene group. Our results indicate that benzene induces increased expression of FA transport and β-oxidation enzymes, mitochondrial dysfunction, and oxidative stress, which may play a role in benzene-induced hematotoxicity.

  4. Glucagon in intravenous cholangiography - an experimental study on dogs

    International Nuclear Information System (INIS)

    Toetterman, S.; Santavirta, S.; Antila, H.

    1980-01-01

    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 [de

  5. Experimental Study of Blood Laminar Flow Through a Stented Artery

    National Research Council Canada - National Science Library

    Benard, N

    2001-01-01

    .... That is why, to study the flow disturbances through a stented section, we built an in vitro model reproducing the struts shapes of a marketed endoprothesis, The experimental artery, is composed...

  6. an experimental study on the use of polypropylene waste

    African Journals Online (AJOL)

    HOD

    PM) asphalt concrete. The specimens ... as poor materials selection and quality, design and construction lapses, climatic ... AN EXPERIMENTAL STUDY ON THE USE OF POLYPROPYLENE WASTE IN BITUMINOUS MIX. H. S. Otuoze & A. A. ...

  7. 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.

  8. Δg: The new aromaticity index based on g-factor calculation applied for polycyclic benzene rings

    Science.gov (United States)

    Ucun, Fatih; Tokatlı, Ahmet

    2015-02-01

    In this work, the aromaticity of polycyclic benzene rings was evaluated by the calculation of g-factor for a hydrogen placed perpendicularly at geometrical center of related ring plane at a distance of 1.2 Å. The results have compared with the other commonly used aromatic indices, such as HOMA, NICSs, PDI, FLU, MCI, CTED and, generally been found to be in agreement with them. So, it was proposed that the calculation of the average g-factor as Δg could be applied to study the aromaticity of polycyclic benzene rings without any restriction in the number of benzene rings as a new magnetic-based aromaticity index.

  9. 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 marrow.......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'-inducing metabolites...

  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. Association between Promoter Methylation of Gene ERCC3 and Benzene Hematotoxicity.

    Science.gov (United States)

    Zheng, Min; Lin, Feiliang; Hou, Fenxia; Li, Guilan; Zhu, Caiying; Xu, Peiyu; Xing, Caihong; Wang, Qianfei

    2017-08-16

    Benzene is a primary industrial chemical and a ubiquitous environmental pollutant. ERCC3 is a key player in nucleotide excision repair. Recent studies suggested that site-specific methylation is a possible mechanism of the transcriptional dysregulation by blocking transcription factors binding. We previously found that the average promoter methylation level of ERCC3 was increased in benzene-exposed workers. In order to test whether specific CpG sites of ERCC3 play an important role in benzene-induced epigenetic changes and whether the specific methylation patterns are associated with benzene hematotoxicity, we analyzed the promoter methylation levels of individual CpG sites, transcription factor binding motif and the correlation between aberrant CpG methylation and hematotoxicity in 76 benzene-exposed workers and 24 unexposed controls in China. Out of all the CpGs analyzed, two CpG units located 43 bp upstream and 99 bp downstream of the transcription start site of ERCC3 (CpG 2-4 and CpG 17-18, respectively), showed the most pronounced increase in methylation levels in benzene-exposed workers, compared with unexposed controls (Mean ± SD: 5.86 ± 2.77% vs. 4.92 ± 1.53%, p = 0.032; 8.45 ± 4.09% vs. 6.79 ± 2.50%, p = 0.024, respectively). Using the JASPAR CORE Database, we found that CpG 2-4 and CpG 17-18 were bound by three putative transcription factors (TFAP2A, E2F4 and MZF1). Furthermore, the methylation levels for CpG 2-4 were correlated negatively with the percentage of neutrophils ( β = -0.676, p = 0.005) in benzene-exposed workers. This study demonstrates that CpG-specific DNA methylation in the ERCC3 promoter region may be involved in benzene-induced epigenetic modification and it may contribute to benzene-induced hematotoxicity.

  12. Benzene and toluene in the surface air of northern Eurasia from TROICA-12 campaign along the Trans-Siberian Railway

    Science.gov (United States)

    Skorokhod, Andrey I.; Berezina, Elena V.; Moiseenko, Konstantin B.; Elansky, Nikolay F.; Belikov, Igor B.

    2017-05-01

    Volatile organic compounds (VOCs) were measured by proton transfer reaction mass spectrometry (PTR-MS) on a mobile laboratory in a transcontinental TROICA-12 (21 July-4 August 2008) campaign along the Trans-Siberian Railway from Moscow to Vladivostok. Surface concentrations of benzene (C6H6) and toluene (C7H8) along with non-methane hydrocarbons (NMHCs), CO, O3, SO2, NO, NO2 and meteorology are analyzed in this study to identify the main sources of benzene and toluene along the Trans-Siberian Railway. The most measurements in the TROICA-12 campaign were conducted under low-wind/stagnant conditions in moderately ( ˜ 78 % of measurements) to weakly polluted ( ˜ 20 % of measurements) air directly affected by regional anthropogenic sources adjacent to the railway. Only 2 % of measurements were identified as characteristic of highly polluted urban atmosphere. Maximum values of benzene and toluene during the campaign reached 36.5 and 45.6 ppb, respectively, which is significantly less than their short-term exposure limits (94 and 159 ppb for benzene and toluene, respectively). About 90 % of benzene and 65 % of toluene content is attributed to motor vehicle transport and 10 and 20 %, respectively, provided by the other local- and regional-scale sources. The highest average concentrations of benzene and toluene are measured in the industrial regions of the European Russia (up to 0.3 and 0.4 ppb for benzene and toluene, respectively) and south Siberia (up to 0.2 and 0.4 ppb for benzene and toluene, respectively). Total contribution of benzene and toluene to photochemical ozone production along the Trans-Siberian Railway is about 16 % compared to the most abundant organic VOC - isoprene. This contribution, however, is found to be substantially higher (up to 60-70 %) in urbanized areas along the railway, suggesting an important role of anthropogenic pollutant sources in regional ozone photochemistry and air quality.

  13. Urban benzene pollution and population exposure

    Energy Technology Data Exchange (ETDEWEB)

    Cocheo, V.; Sacco, P.; Boaretto, C. [Fondazione Salvatore, Maugeri-IRCCS, Padova (Italy); Saeger, E. de; Ballesta, P.P. [Joint Research Centre, Ispra (Italy); Skov, H. [National Environmental Research Institute, Frederiksborgvej (Denmark); Goelen, E. [Vlaamse Instelling voor Technologisch Onderzoek, Mol (Belgium); Gonzalez, N. [Institut National de l' environnement Industriel et des Risques, 60 - Verneuil en Halatte (France); Caracena, A.B. [Universidad de Murcia, Dept. de Ingenieria Quimica-Murcia (Spain)

    2001-07-01

    Benzene is among the gasoline components and is airborne by vehicular traffic. It is a myelo-toxic and leukaemia-inducing compound. The risk level, expressed as myeloid leukaemia cases increment estimate among the population not professionally exposed to benzene, has been stated to range 3.8 to 7.5 cases every million people exposed during the lifetime to 1 {mu}g/m{sup 3}. All the estimates deal with exposure, not with environmental concentration. Since the two parameters can be not coincident, the citizens' risk level, which depends on actual exposure, can not be simply estimated by means of urban pollution. Therefore, once a socially acceptable exposure risk level is stated by a political decision, one can set a limiting value for benzene concentration in urban air only if the relationship between personal exposure and urban pollution is known. We find the citizens' exposure level, whatever their occupation or the fraction of time spent outdoors, is higher than urban average level and is equal, on average in Europe, to twice its value. To establish this relationship, six towns and a sample of their citizens and their homes have undergone environmental monitoring for an entire year. The towns were distributed among the Northern, Central and Southern European countries, comprising a wide range of different lifestyles, climates and development features. (authors)

  14. Synthesis, spectral and quantum chemical studies and use of (E)-3-[(3,5-bis(trifluoromethyl)phenylimino)methyl]benzene-1,2-diol and its Ni(II) and Cu(II) complexes as an anion sensor, DNA binding, DNA cleavage, anti-microbial, anti-mutagenic and anti-cancer agent

    Science.gov (United States)

    Ünver, Hüseyin; Boyacıoğlu, Bahadır; Zeyrek, Celal Tuğrul; Yıldız, Mustafa; Demir, Neslihan; Yıldırım, Nuray; Karaosmanoğlu, Oğuzhan; Sivas, Hülya; Elmalı, Ayhan

    2016-12-01

    We report the synthesis of a novel Schiff base (E)-3-[(3,5-bis(trifluoromethyl) phenylimino)methyl] benzene-1,2-diol from the reaction of 2,3-dihydroxybenzaldehyde with 3,5-bis(trifluoromethyl)aniline, and its Ni(II) and Cu(II) complexes. The molecular structure of the Schiff base was experimentally determined using X-ray single-crystal data and was compared to the structure predicted by theoretical calculations using density functional theory (DFT), Hartree-Fock (HF) and Möller-Plesset second-order perturbation (MP2). In addition, nonlinear optical (NLO) effects of the compound was predicted using DFT. The antimicrobial activities of the compounds were investigated for their minimum inhibitory concentration. UV-Vis spectroscopy studies of the interactions between the compounds and calf thymus DNA (CT-DNA) showed that the compounds interacts with CT-DNA via intercalative binding. A DNA cleavage study showed that the Cu(II) complex cleaved DNA without any external agents. The compounds inhibited the base pair mutation in the absence of S9 with high inhibition rate. In addition, in vitro cytotoxicity of the Ni(II) complex towards HepG2 cell line was assayed by the MTT method. Also, the colorimetric response of the Schiff base in DMSO to the addition of equivalent amount of anions (F-, Br-, I-, CN-, SCN-, ClO4-, HSO4-, AcO-, H2PO4-, N3- and OH-) was investigated. In this regard, while the addition of F-, CN-, AcO- and OH- anions into the solution containing Schiff base resulted in a significant color change, the addition of Br-, I-, SCN-, ClO4-, HSO4-, H2PO4- and N3- anions resulted in no color change. The most discernable color change in the Schiff base was caused by CN-, which demonstrated that the ligand can be used to selectively detect CN-.

  15. 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.

  16. Incense, sparklers and cigarettes are significant contributors to indoor benzene and particle levels.

    Science.gov (United States)

    Tirler, Werner; Settimo, Gaetano

    2015-01-01

    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. 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. 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/m of benzene in the test room after the incense sticks had been tested.

  17. THE INFLUENCE OF BENZENE AS A TRACE REACTANT IN TITAN AEROSOL ANALOGS

    International Nuclear Information System (INIS)

    Trainer, Melissa G.; Sebree, Joshua A.; Heidi Yoon, Y.; Tolbert, Margaret A.

    2013-01-01

    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 6 H 6 /CH 4 /N 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 4 /N 2 . Our results show that even a trace amount of C 6 H 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 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.

  18. Evaluation of inflammatory reactions and genotoxic effects after exposure of nasal respiratory epithelia to benzene.

    Science.gov (United States)

    Gosepath, Jan; Grebneva, Nina; Brieger, Juergen; Mann, Wolf J

    2003-01-01

    The aim of this study was to identify inflammatory changes as well as genotoxic effects in cultivated human respiratory epithelial cells after in vitro exposure to benzene. Primary cell cultures of nasal respiratory mucosa were exposed to synthetic air enriched with 5,000 microg/m(3) of benzene at an air/liquid interface over 8 h and then to synthetic air only over the following 24 h. Controls were continuously exposed to synthetic air over 32 h. To detect inflammatory reactions, release of prostaglandin E(2) was quantified using a competitive enzyme immunoassay. The Comet Assay was used to quantify the ratio of apoptotic cells with benzene-induced DNA fragmentation. Prostaglandin release as well as DNA fragmentation increased after 8 h of exposure and remained elevated throughout the following 24 h but did not increase in controls. High concentrations of benzene induce an inflammatory response and possibly fragmentation of DNA in respiratory epithelial cells. These findings have to be discussed with respect to possible mutagenic or carcinogenic effects of benzene in nasal respiratory cells. Copyright 2003 S. Karger AG, Basel

  19. Removal efficiencies of constructed wetland and efficacy of plant on treating benzene

    Directory of Open Access Journals (Sweden)

    Florencio Ballesteros, Jr.

    2016-03-01

    Full Text Available Leaking underground petroleum storage poses human and environmental health risks as it contaminates the soil and the groundwater. Of the many contaminants, benzene – a major constituent of gasoline, is of primary concern. It is an identified carcinogen with a permissible limit set at a low level of 0.005 mg L−1. This poses technical and regulatory challenge to remediation of contaminated sites. Various specialized treatment methods are available, but despite of the high removal efficiencies of sophisticated treatments, the residual level still poses health risks. Thus, additional alternative ways that are cost effective and require minimum technical expertise are necessary, and a constructed wetland (CW is a potential alternative. This study evaluates the performance of a surface flow type CW for the removal of benzene from the contaminated water. It further determines the efficacy of a common reed plant Phragmites karka in treating benzene. Planted and unplanted CW were acclimated with benzene for 16 wk and tested for an 8-d hydraulic retention time at benzene levels of 66 and 45 mg L−1. Results indicate that the planted CW performed better and gave reliable and stable results.

  20. Molecular Self-Assembly of Group 11 Pyrazolate Complexes as Phosphorescent Chemosensors for Detection of Benzene

    Science.gov (United States)

    Ghazalli, N. F.; Yuliati, L.; Lintang, H. O.

    2018-01-01

    We highlight the systematic study on vapochromic sensing of aromatic vapors such as benzene using phosphorescent trinuclear pyrazolate complexes (2) with supramolecular assembly of a weak intermolecular metal-metal interaction consisting of 4-(3,5-dimethoxybenzyl)-3,5-dimethyl pyrazole ligand (1) and group 11 metal ions (Cu(I), Ag(I), Au(I)). The resulting chemosensor 2(Cu) revealed positive response to benzene vapors in 5 mins by blue-shifting its emission band in 44 nm (from 616 to 572 nm) and emitted bright orange to green, where this change cannot be recovered even with external stimuli. Comparing to 2(Ag) with longer metal-metal distance (473 nm) with same sensing time and quenching in 37%, 2(Au) gave quenching in 81% from its original intensity at 612 nm with reusability in 82% without external stimuli and emitted less emissive of red-orange from its original color. The shifting phenomenon in 2(Cu) suggests diffusion of benzene vapors to inside molecules for formation of intermolecular interaction with Cu(I)-Cu(I) interaction while quenching phenomenon in 2(Au) suggests diffusion of benzene vapors to between the Au(I)-Au(I) interaction. These results indicate that suitable molecular structure of ligand and metal ion in pyrazolate complex is important for designing chemosensor in the detection of benzene vapors.

  1. Assisted bioremediation tests on three natural soils contaminated with benzene

    Directory of Open Access Journals (Sweden)

    Maria Manuela Carvalho

    2015-07-01

    Full Text Available Bioremediation is an attractive and useful method of remediation of soils contaminated with petroleum hydrocarbons because it is simple to maintain, applicable in large areas, is economic and enables an effective destruction of the contaminant. Usually, the autochthone microorganisms have no ability to degrade these compounds, and otherwise, the contaminated sites have inappropriate environmental conditions for microorganism’s development. These problems can be overcome by assisted bioremediation (bioaugmentation and/or biostimulation. In this study the assisted bioremediation capacity on the rehabilitation of three natural sub-soils (granite, limestone and schist contaminated with benzene was evaluated. Two different types of assisted bioremediation were used: without and with ventilation (bioventing. The bioaugmentation was held by inoculating the soil with a consortium of microorganisms collected from the protection area of crude oil storage tanks in a refinery. In unventilated trials, biostimulation was accomplished by the addition of a nutrient mineral media, while in bioventing oxygen was also added. The tests were carried out at controlled temperature of 25 ºC in stainless steel columns where the moist soil contaminated with benzene (200 mg per kg of soil occupied about 40% of the column’s volume. The processes were daily monitored in discontinued mode. Benzene concentration in the gas phase was quantified by gas chromatography (GC-FID, oxygen and carbon dioxide concentrations were monitored by respirometry. The results revealed that the three contaminated soils were remediated using both technologies, nevertheless, the bioventing showed faster rates. With this work it was proved that respirometric analysis is an appropriate instrument for monitoring the biological activity.

  2. Low-energy structures of benzene clusters with a novel accurate potential surface.

    Science.gov (United States)

    Bartolomei, M; Pirani, F; Marques, J M C

    2015-12-05

    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. © 2015 Wiley Periodicals, Inc.

  3. An experimental study on superplastic behaviors of magnesium alloy sheet

    Energy Technology Data Exchange (ETDEWEB)

    Jin Quanlin; Wu Huiying [Beijing Research Inst. of Mechanical and Electrical Technology (China)

    2005-07-01

    An experimental study on superplastic forming behaviors and microstructure characters of commercial magnesium alloy sheet AZ31B is presented in this paper. The main experimental results show that the commercial magnesium alloy AZ31B sheet has superplastic capability. For the received sheet without any pre-processing, the maximum elongation is 295%. The dynamic recrystallization and grain refinement can be found. The superplastic behaviors can be improved by controlling the dynamic recrystallization and grain refinement. Some experimental results of free superplastic bulging are presented in this paper. The results show that influence of temperature on forming capability is much less than the influences of temperature on elongation. (orig.)

  4. Using an experimental model for the study of therapeutic touch.

    Science.gov (United States)

    dos Santos, Daniella Soares; Marta, Ilda Estéfani Ribeiro; Cárnio, Evelin Capellari; de Quadros, Andreza Urba; Cunha, Thiago Mattar; de Carvalho, Emilia Campos

    2013-02-01

    to verify whether the Paw Edema Model can be used in investigations about the effects of Therapeutic Touch on inflammation by measuring the variables pain, edema and neutrophil migration. this is a pilot and experimental study, involving ten male mice of the same genetic strain and divided into experimental and control group, submitted to the chemical induction of local inflammation in the right back paw. The experimental group received a daily administration of Therapeutic Touch for 15 minutes during three days. the data showed statistically significant differences in the nociceptive threshold and in the paw circumference of the animals from the experimental group on the second day of the experiment. the experiment model involving animals can contribute to study the effects of Therapeutic Touch on inflammation, and adjustments are suggested in the treatment duration, number of sessions and experiment duration.

  5. CdFe2O4 thin films for the detection of benzene vapors

    Science.gov (United States)

    Nagarajan, V.; Thayumanavan, A.

    2018-02-01

    Spinel cadmium ferrite thin films were prepared using spray pyrolysis technique. The structural analysis of synthesized CdFe2O4 thin films shows the spinel structure, which exhibits polycrystalline nature. Morphological study confirms that the crystallites of CdFe2O4 thin film have island-like nature. The size of the crystallite is recorded to be around 13.0-37 nm. Energy-dispersion spectroscopy confirms the presence of oxygen, iron and cadmium in cadmium ferrites film. The prepared CdFe2O4 thin film is extremely sensitive towards toxic benzene vapor molecules at ambient temperature. The resistance of synthesized CdFe2O4 thin film decreases considerably when this material is exposed to benzene vapor molecules. The selectivity, stability, recovery time, sensitivity and response time of CdFe2O4 thin film towards benzene vapor molecules were explored in the present study.

  6. 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...

  7. Effects of the presence of ethylacetate or benzene on the densities and volumetric properties of mixture (styrene + N,N-dimethylformamide)

    International Nuclear Information System (INIS)

    Li Fanli; Tang Rencheng

    2007-01-01

    Densities have been measured as a function of composition for a ternary-pseudobinary mixture of {(styrene + ethyl acetate or benzene) + (N,N-dimethylformamide + ethyl acetate or benzene)} by means of a vibrating-tube densimeter at atmospheric pressure and the temperature 298.15 K. The excess molar volumes V m E were calculated from the densities and correlated using the Redlich-Kister equation to estimate the coefficients and standard errors. The experimental and calculated quantities are used to discuss the mixing behaviour of the components. The results show the third component, ethyl acetate or benzene, have a significant influence on the interaction between styrene and N,N-dimethylformamide

  8. Room Temperature Detection of Benzene Vapours by Tin Oxide Nano Clusters

    Directory of Open Access Journals (Sweden)

    J. N. PANCHAL

    2015-07-01

    Full Text Available Thin films of tin oxide with nano clusters were deposited using Chemical Vapour Transport technique. The annealed films were used as sensor to detect benzene vapours at room temperature. The response was studied for the concentration range 300-1000 ppm. A comparative study of the response of the nano clustered films to benzene vapours in this range with the response of thin films of Indium tin oxide and tin oxide deposited by the physical vapour deposition method was taken up.

  9. Synthesis, antimicrobial, anticancer, antiviral evaluation and QSAR studies of 4-(1-aryl-2-oxo-1,2-dihydro-indol-3-ylideneamino-N-substituted benzene sulfonamides

    Directory of Open Access Journals (Sweden)

    Mahesh Kumar

    2014-09-01

    Full Text Available A series of 4-(1-aryl-2-oxo-1,2-dihydro-indol-3-ylideneamino-N-substituted benzenesulfonamide derivatives (1–32 was synthesized and evaluated for its in vitro antimicrobial, antiviral and cytotoxic activities. Antimicrobial results indicated that compounds (11 and (18 were found to be the most effective ones. In general, the synthesized compounds were bacteriostatic and fungistatic in their action. The cytotoxic screening results indicated that the compounds were less active than the standard drug 5-fluorouracil (5-FU. None of the compounds inhibited viral replication at subtoxic concentrations. In general, the presence of a pyrimidine ring with electron releasing groups and an ortho- and para-substituted benzoyl moiety favored antimicrobial activities. The results of QSAR studies demonstrated the importance of topological parameters, valence zero order molecular connectivity index (0χv and valence first order molecular connectivity index (1χv in describing the antimicrobial activity of synthesized compounds.

  10. 4-(1-Aryl-5-chloro-2-oxo-1,2-dihydro-indol-3-ylideneamino-N-substituted benzene sulfonamides: Synthesis, antimicrobial, anticancer evaluation and QSAR studies

    Directory of Open Access Journals (Sweden)

    Mahesh Kumar

    2014-09-01

    Full Text Available A series of 4-(1-aryl-5-chloro-2-oxo-1,2-dihydro-indol-3-ylideneamino-N-substituted benzenesulfonamide derivatives (1–20 was synthesized and evaluated for its in vitro antimicrobial and anticancer activities. Antimicrobial results indicated that compounds N-(4-(1-benzoyl-5-chloro-2-oxoindolin-3-ylideneamino phenylsulfonyl-4-isopropoxy benzamide (9 and N-(4-(5-chloro-1-(2-chlorobenzoyl-2-oxoindolin-3-ylideneamino phenylsulfonyl-4-isopropoxybenzamide (19 were found to be the most effective ones. The anticancer results indicated that almost all the synthesized compounds were more active than the standard drug carboplatin but less active than the standard drug 5-fluorouracil (5-FU against both the cell lines (HCT116 and RAW 264.7. 4-(1-Benzoyl-5-chloro-2-oxoindolin-3-ylideneamino-N-(pyrimidin-2-yl benzenesulfonamide (3 was found to be most potent and exhibited selectivity toward HCT 116. QSAR studies indicated that antimicrobial activity of isatin derivatives against different microbial strains was governed by lipophilic parameter, log P and topological parameters valance zero and third order molecular connectivity indices (0χv and 3χv.

  11. OH-initiated oxidation of benzene - Part II. Influence of elevated NOx concentrations

    DEFF Research Database (Denmark)

    Klotz, B; Volkamer, R; Hurley, MD

    2002-01-01

    The present work represents a continuation of part I of this series of papers, in which we investigated the phenol yields in the OH-initiated oxidation of benzene under conditions of low to moderate concentrations of NOx, to elevated NOx levels. The products of the OH-initiated oxidation of benzene...... in 700 760 Torr of N-2/O-2 diluent at 297 +/- 4 K were investigated in 3 different photochemical reaction chambers. In situ spectroscopic techniques were employed for the detection of products, and the initial concentrations of benzene, NOx, and O-2 were widely varied (by factors of 6300, 1500, and 13......, respectively). In contrast to results from previous studies, a pronounced dependence of the product distribution on the NOx concentration was observed. The phenol yield decreases from approximately 50-60% in the presence of low concentrations (10 000 ppb) NOx concentrations. In the presence of high...

  12. A new dietary model to study colorectal carcinogenesis: experimental design, food preparation, and experimental findings.

    Science.gov (United States)

    Rozen, P; Liberman, V; Lubin, F; Angel, S; Owen, R; Trostler, N; Shkolnik, T; Kritchevsky, D

    1996-01-01

    Experimental dietary studies of human colorectal carcinogenesis are usually based on the AIN-76A diet, which is dissimilar to human food in source, preparation, and content. The aims of this study were to examine the feasibility of preparing and feeding rats the diet of a specific human population at risk for colorectal neoplasia and to determine whether changes in the colonic morphology and metabolic contents would differ from those resulting from a standard rat diet. The mean daily food intake composition of a previously evaluated adenoma patient case-control study was used for the "human adenoma" (HA) experimental diet. Foods were prepared as for usual human consumption and processed by dehydration to the physical characteristics of an animal diet. Sixty-four female Sprague-Dawley rats were randomized and fed ad libitum the HA or the AIN-76A diet. Every eight weeks, eight rats from each group were sacrificed, and the colons and contents were examined. Analysis of the prepared food showed no significant deleterious changes; food intake and weight gain were similar in both groups. Compared with the controls, the colonic contents of rats fed the HA diet contained significantly less calcium, concentrations of neutral sterols, total lipids, and cholic and deoxycholic acids were increased, and there were no colonic histological changes other than significant epithelial hyperproliferation. This initial study demonstrated that the HA diet can be successfully processed for feeding to experimental animals and is acceptable and adequate for growth but induces significant metabolic and hyperproliferative changes in the rat colon. This dietary model may be useful for studies of human food, narrowing the gap between animal experimentation and human nutritional research.

  13. Computer simulations of homogeneous nucleation of benzene from the melt.

    Science.gov (United States)

    Shah, Manas; Santiso, Erik E; Trout, Bernhardt L

    2011-09-08

    Nucleation is the key step in crystallization by which the molecules (or atoms or ions) aggregate together, find the right relative orientations, and start to grow to form the final crystal structure. Since nucleation is an activated step involving a large gap in time scales between molecular motions and the nucleation event itself, nucleation must be studied using rare events methods. We employ a technique developed previously in our group known as aimless shooting [Peters, B.; Trout, B. L. J. Chem. Phys., 2006, 125, 054108], which is based on transition path sampling, to generate reactive trajectories between the disordered and ordered phases of benzene. Using the likelihood maximization algorithm, we analyze the aimless shooting trajectories to identify the key order parameters or collective variables to describe the reaction coordinate for the nucleation of benzene from the melt. We find that the local bond orientation and local relative orientation order parameters are the most important collective variables in describing the reaction coordinate for homogeneous nucleation from the melt, as compared to cluster size and space-averaged order parameters. This study also demonstrates the utility of recently developed order parameters for molecular crystals [Santiso, E. E.; Trout, B. L. J. Chem. Phys., 2011, 134, 064109].

  14. Physiological and phylogenetic characterization of a stable benzene-degrading, chlorate-reducing microbial community

    NARCIS (Netherlands)

    Weelink, S.A.B.; Tan, N.C.G.; Broeke, H. ten; Doesburg, W. van; Langenhoff, A.A.M.; Gerritse, J.; Stams, A.J.M.

    2007-01-01

    A stable anoxic enrichment culture was obtained that degraded benzene with chlorate as an electron acceptor. The benzene degradation rate was 1.65 mM benzene per day, which is similar to reported aerobic benzene degradation rates but 20-1650 times higher than reported for anaerobic benzene

  15. What Shapes the Intention to Study Abroad? An Experimental Approach

    Science.gov (United States)

    Petzold, Knut; Moog, Petra

    2018-01-01

    In contrast to previous studies, this investigation aims to get deeper insights into the causes of the intention to study abroad by using an experimental approach. Although international experience is often considered as important, many students at German universities do not even consider abroad. Referring to the Theory of Rational Choice (RCT)…

  16. Experimental study of mechanical properties of friction welded AISI ...

    Indian Academy of Sciences (India)

    Friction welding is widely used as a mass production method in various industries. In the present study, an experimental set-up was designed in order to achieve friction welding of plastically deformed AISI 1021 steels. In this study, low alloy steel (AISI 1021) was welded under different welding parameters and afterwards ...

  17. Experimental and theoretical study of precast beam-slab construction

    African Journals Online (AJOL)

    Part of the experimental program was dedicated to the study of mix design for the production of suitable hollow concrete beam tiles which bridge the space between the precast beam elements. The second part of the test program included the study of the precast beam element alone in order to investigate the response ...

  18. Infections in orthopaedic surgery : clinical and experimental studies

    NARCIS (Netherlands)

    Vogely, Henri Charles

    2000-01-01

    The diagnostic difficulties, variability in outcome and the heterogeinity of the problem of orthopaedic infections stimulated the author to a study of the literature, and several clinical and experimental studies. The diagnosis prosthesis-related infection can only be reached with an acceptable

  19. Experimental studies on the flow through soft tubes and channels

    Indian Academy of Sciences (India)

    studies were designed to examine whether the compliance of dolphin skins could cause either transition delay, that is, an increase in the Reynolds number for laminar-turbulent transition or a reduction in the turbulence intensities. The first experimental studies on internal flows through conduits bounded by soft walls was.

  20. Experimental studies on an indigenous coconut shell based ...

    Indian Academy of Sciences (India)

    Satyabrata Sahoo

    studies on material characteristics, adsorption isotherms and kinetics of a coconut shell based activated carbon are presented. It is expected that these results will promote large scale use of the indigenous material that is also environment friendly and inexpensive. 2. Experimental studies. 2.1 Materials used. 2.1a Activated ...